elastin and Disease-Models--Animal

Several studies have implicated a causative role for specific matrix metalloproteinases (MMPs) in the development and progression of cigarette smoke-induced chronic obstructive pulmonary disease (COPD) and its severe sequela, emphysema. However, the precise function of any given MMP in emphysema remains an unanswered question. Emphysema results from the degradation of alveolar elastin - among other possible mechanisms - a process that is often thought to be caused by elastolytic proteinases made by macrophages. In this article, we discuss the data suggesting, supporting, or refuting causative roles of macrophage-derived MMPs, with a focus on MMPs-7, -9, -10, -12, and 28, in both the human disease and mouse models of emphysema. Findings from experimental models suggest that some MMPs, such as MMP-12, may directly breakdown elastin, whereas others, particularly MMP-10 and MMP-28, promote the development of emphysema by influencing the proteolytic and inflammatory activities of macrophages.

Topics: Animals; Disease Models, Animal; Elastin; Genetic Predisposition to Disease; Humans; Macrophages; Matrix Metalloproteinases; Mice; Polymorphism, Single Nucleotide; Proteolysis; Pulmonary Emphysema

Obstructive sleep apnea (OSA) is highly prevalent in the USA and is recognized as an independent risk factor for atherosclerotic cardiovascular disease. Identification of atherosclerosis risk factor attributable to OSA may provide opportunity to develop preventive measures for cardiovascular risk reduction. Chronic intermittent hypoxia (CIH) is a prominent feature of OSA pathophysiology and may be a major mechanism linking OSA to arteriosclerosis. Animal studies demonstrated that CIH exposure facilitated high-cholesterol diet (HCD)-induced atherosclerosis, accelerated the progression of existing atherosclerosis, and induced atherosclerotic lesions in the absence of other atherosclerosis risk factors, demonstrating that CIH is an independent causal factor of atherosclerosis. Comparative studies revealed major differences between CIH-induced and the classic HCD-induced atherosclerosis. Systemically, CIH was a much weaker inducer of atherosclerosis. CIH and HCD differentially activated inflammatory pathways. Histologically, CIH-induced atherosclerotic plaques had no clear necrotic core, contained a large number of CD31+ endothelial cells, and had mainly elastin deposition, whereas HCD-induced plaques had typical necrotic cores and fibrous caps, contained few endothelial cells, and had mainly collagen deposition. Metabolically, CIH caused mild, but HCD caused more severe dyslipidemia. Mechanistically, CIH did not, but HCD did, cause macrophage foam cell formation. NF-κB p50 gene deletion augmented CIH-induced, but not HCD-induced atherosclerosis. These differences reflect the intrinsic differences between the two types of atherosclerosis in terms of pathological nature and underlying mechanisms and support the notion that CIH-induced atherosclerosis is a new paradigm that differs from the classic HCD-induced atherosclerosis.

Topics: Animals; Atherosclerosis; Cholesterol, Dietary; Collagen; Diet, Atherogenic; Disease Models, Animal; Elastin; Foam Cells; Gene Knockout Techniques; Humans; Hypoxia; NF-kappa B; Risk Factors; Signal Transduction; Sleep Apnea, Obstructive

Large artery stiffness, as measured by pulse wave velocity, is correlated with high blood pressure and may be a causative factor in essential hypertension. The extracellular matrix components, specifically the mix of elastin and collagen in the vessel wall, determine the passive mechanical properties of the large arteries. Elastin is organized into elastic fibers in the wall during arterial development in a complex process that requires spatial and temporal coordination of numerous proteins. The elastic fibers last the lifetime of the organism but are subject to proteolytic degradation and chemical alterations that change their mechanical properties. This review discusses how alterations in the amount, assembly, organization, or chemical properties of the elastic fibers affect arterial stiffness and blood pressure. Strategies for encouraging or reversing alterations to the elastic fibers are addressed. Methods for determining the efficacy of these strategies, by measuring elastin amounts and arterial stiffness, are summarized. Therapies that have a direct effect on arterial stiffness through alterations to the elastic fibers in the wall may be an effective treatment for essential hypertension.

Topics: Age Factors; Animals; Antihypertensive Agents; Arteries; Blood Pressure; Compliance; Disease Models, Animal; Elastic Tissue; Elastin; Genetic Predisposition to Disease; Hemodynamics; Humans; Hypertension; Mutation; Pulsatile Flow; Risk Factors

Aortic aneurysm is common, accounting for 1-2% of all deaths in industrialized countries. Early theories of the causes of human aneurysm mostly focused on inherited or acquired defects in components of the extracellular matrix in the aorta. Although several mutations in the genes encoding extracellular matrix proteins have been recognized, more recent discoveries have shown important perturbations in cytokine signalling cascades and intracellular components of the smooth muscle contractile apparatus. The modelling of single-gene heritable aneurysm disorders in mice has shown unexpected involvement of the transforming growth factor-β cytokine pathway in aortic aneurysm, highlighting the potential for new therapeutic strategies.

Topics: Angiotensin II; Animals; Aortic Aneurysm; Disease Models, Animal; Elastin; Humans; Muscle, Smooth, Vascular; Transforming Growth Factor beta

Animal models of large artery wall stiffness fall into two categories: firstly those that slowly develop multifactorial vascular dysfunction spontaneously, such as the ageing rat. The second type of model consists of those in which a specific pathology is induced by surgical, chemical, or genetic means. Such models are based on a short-term, highly traumatic insult to the arterial wall of a young animal and its acute reaction to such insult. This is very different from the human situation in which changes in wall stiffness arise from the long-term accumulation of relatively minor episodes of vascular insult in the vulnerable elderly.

Topics: Animals; Arteries; Arteriosclerosis; Calcinosis; Collagen; Disease Models, Animal; Elastin; Humans; Hypertension; Neurotransmitter Agents; Pancreatic Elastase; Renin-Angiotensin System; Vascular Resistance

1. Arterial stiffness, which has independent predictive value for cardiovascular events, seems to have a genetic component, largely independent of the influence of blood pressure and other cardiovascular risk factors. 2. In animal models of essential hypertension (stroke-prone spontaneously hypertensive rats and spontaneously hypertensive rats), structural modifications of the arterial wall include an increase in the number of elastin-smooth muscle cell connections and smaller fenestrations of the internal elastic lamina, possibility leading to redistribution of the mechanical load towards elastic materials. These modifications may give rise to mechanisms explaining why changes in arterial wall material accompanying wall hypertrophy in these animals are not associated with an increase in arterial stiffness. 3. In monogenic connective tissue diseases (Marfan, Williams and Ehlers-Danlos syndromes) and the corresponding animal models, precise characterization of the arterial phenotype makes it possible to determine the influence of abnormal, genetically determined, wall components on arterial stiffness. 4. Such studies have highlighted the role of extracellular matrix signalling in the vascular wall and have shown that elastin and collagen not only display elasticity or rigidity, but are also involved in the control of smooth muscle cell function. 5. These data provide strong evidence that arterial stiffness is affected by the amount and density of stiff wall material and the spatial organization of that material.

Topics: Animals; Arteries; Cardiovascular Diseases; Collagen; Compliance; Disease Models, Animal; Ehlers-Danlos Syndrome; Elastin; Extracellular Matrix; Gene Expression Profiling; Genetic Predisposition to Disease; Humans; Hypertension; Marfan Syndrome; Oligonucleotide Array Sequence Analysis; Polymorphism, Genetic; Risk Factors; Tunica Intima; Tunica Media; Williams Syndrome

Studies of autoimmune diseases have not yet elucidated why certain organs or vessels become the objects of injury while others are spared. This paper explores the hypothesis that important differences exist in regions of the aorta; these regional variations determine vulnerability to such diseases as atherosclerosis, aortitis, giant-cell arteritis, and Takayasu's disease. The reader is invited to reassess two issues: (1) whether the aorta is indeed a single homogeneous structure; and (2) whether the initial stage of aortitis (and indeed other diseases considered "autoimmune") may primarily be the result of acquired alterations of substrate that influence unique immune profiles, but that by themselves may not be pathogenic. Disease susceptibility and patterns are influenced by many factors that are either inborn or acquired. Examples include genetic background, gender, ethnicity, aging, prior and concomitant illnesses, habits, diet, and exposure to toxins and other environmental hazards. Studies of vascular diseases must assess how such variables affect regional anatomic differences in endothelial cells, subendothelial matrix, and vascular smooth muscle, as well as the response of each to a variety of stimuli.

Topics: Aging; Animals; Aortitis; Atherosclerosis; Collagen; Disease Models, Animal; Elastin; Giant Cell Arteritis; Humans; Immune System; Takayasu Arteritis; Vasculitis

Topics: Animals; Biological Factors; Bronchi; Child; Disease Models, Animal; Elastin; Extracellular Matrix; Humans; Hypoxia; Infant; Infant, Newborn; Infant, Premature, Diseases; Lung; Lung Diseases; Lung Transplantation; Mechanotransduction, Cellular; Oxygen; Pluripotent Stem Cells; Pulmonary Alveoli; Pulmonary Artery; Respiration; Species Specificity

Cardiovascular disease is largely a consequence of coronary artery blockage through excessive proliferation of smooth muscle cells. It in turn leads to myocardial infarction and permanent and functionally devastating tissue damage to the heart wall. Our studies have revealed that elastin is a primary player in maintaining vascular smooth muscle cells in their dormant state and thus may be a useful therapeutic in vascular disease. By studying zebrafish, which unlike humans, can repair damage to heart muscle, we have begun to uncover some of the genes that seem necessary to undertake the de-differentiation steps that currently fail and prevent the formation of new proliferating cardiomyocytes at the site of damage in a mammalian heart.

Topics: Animals; Cardiovascular Diseases; Cell Differentiation; Coronary Vessels; Disease Models, Animal; Elastin; Heart; Humans; Muscle, Smooth; Regeneration; Zebrafish

Topics: Animals; Biomechanical Phenomena; Causality; Collagen; Disease Models, Animal; Elastin; Emphysema; Forced Expiratory Volume; Humans; Pancreatic Elastase; Pneumonectomy; Rats; Respiratory Mechanics; Tidal Volume

Topics: Airway Obstruction; Animals; Bronchiolitis; Collagen; Collagenases; Disease Models, Animal; Elastin; Humans; Prognosis; Pulmonary Alveoli; Pulmonary Emphysema; Tretinoin

The inability to study appropriate human tissues at various stages of development has precluded the elaboration of a thorough understanding of the pathogenic mechanisms leading to diseases linked to mutations in genes for elastic fiber proteins. Recently, new insights have been gained by studying mice harboring targeted mutations in the genes that encode fibrillin-1 and elastin. These genes have been linked to Marfan syndrome (MFS) and supravalvular aortic stenosis (SVAS), respectively. For fibrillin-1, mouse models have revealed that phenotype is determined by the degree of functional impairment. The haploinsufficiency state or the expression of low levels of a product with dominant-negative potential from one allele is associated with mild phenotypes with a predominance of skeletal features. Exuberant expression of a dominant-negative-acting protein leads to the more severe MFS phenotype. Mice harboring targeted deletion of the elastin gene (ELN) show many of the features of SVAS in humans, including abnormalities in the vascular wall and altered hemodynamics associated with changes in wall compliance. The genetically altered mice suggest that SVAS is predominantly a disease of haploinsufficiency. These studies have underscored the prominent role of the elastic matrix in the morphogenesis and homeostasis of the vessel wall.

Topics: Animals; Aortic Stenosis, Supravalvular; Connective Tissue Diseases; Disease Models, Animal; Elastin; Extracellular Matrix Proteins; Fibrillin-1; Fibrillins; Humans; Marfan Syndrome; Mice; Microfilament Proteins; Models, Genetic; Mutation

Experimental aortic aneurysm may be evoked in animals by application of chemical compounds disturbing biosynthesis, posttranslating modifications and degradation of elastin and collagen, local damage of the aortic wall by chemical, thermal and mechanical factors and by increased blood pressure. Administration of protease inhibitors, anti-inflammatory drugs, agents enhancing synthesis and formation of elastic and collagen fibers and hypotensive drugs prevent formation enlargement and rupture of aneurysm.

Topics: Aneurysm, Ruptured; Animals; Aortic Aneurysm; Collagen; Disease Models, Animal; Elastin; Hemodynamics; Proline

Topics: Animals; Disease Models, Animal; Elastin; History, 19th Century; History, 20th Century; Humans; Pulmonary Emphysema

Topics: Aerosols; alpha 1-Antitrypsin Deficiency; Animals; Blood Platelets; Cadmium; Collagen; Disease Models, Animal; Elastin; Emphysema; Forecasting; Hexanes; Lathyrism; Macrophages; Mice; Mice, Mutant Strains; Microscopy, Electron; Neutrophils; Nutrition Disorders; Oxygen; Pancreatic Elastase; Papain; Physical Exertion; Pulmonary Fibrosis; Pulmonary Gas Exchange; Pulmonary Heart Disease; Respiration; Trypsin

Topics: Animals; Disease Models, Animal; Elastin; Humans; Lung; Lung Diseases; Pancreatic Elastase

Aging of human skin represents a complex situation where several factors contribute to the age-related changes. One of these factors relates to UV-radiation, but the exact mechanistic details are not well established. Several morphologic studies have indicated definite changes in the quantitative aspects of dermal connective tissue components, collagen and elastin. Also, recent biochemical studies have suggested that UV-irradiation can alter the metabolism of these proteins in the skin. This review summarizes the current state of knowledge of the effects of natural and therapeutic UV-radiation on dermal connective tissue, and further delineates additional research needs necessary for disclosure of the exact mechanistic details of the aging processes in human skin.

Topics: Animals; Collagen; Connective Tissue; Connective Tissue Diseases; Disease Models, Animal; Elastin; Fibroblasts; Humans; Mice; Photochemotherapy; PUVA Therapy; Skin; Ultraviolet Rays

Many studies have been carried out in the past 10 yr dealing with the possible role of elastase in the pathogenesis of pulmonary emphysema. These include newer observations in animal models revealing augmentation of elastase-induced lesions by lathyrogens or by exposure to cigarette smoke. In general, the animal model experiments have focussed attention on repair-processes in the lung and shown that such processes may exert a major influence on the outcome of the initial proteolytic insult. Human studies exploring correlations between elastase levels in neutrophils or serum and development of disease have provided conflicting data; however, measurement of enzymes in pulmonary secretions have yielded more suggestive results. Assessments of lung elastase inhibitors in humans continue to support the importance of alpha-1-proteinase inhibitor in the protection of the lower respiratory tract, but newer information on locally produced, low molecular weight elastase inhibitors indicates that these, too, may play a significant role. Attempts have been made to link cigarette smoking to the development of emphysema at the chemical and cellular levels. These studies have focussed on: (1) the recruitment of elastase-producing leukocytes to smokers' lungs, (2) inactivation of lung elastase-inhibitors by tobacco products or by metabolites released from tobacco-stimulated lung cells, and (3) interference with elastin neosynthesis (repair) in the smoker. Additional information is also available concerning the biochemical properties of neutrophil and macrophage elastases, although it is still unclear which of these enzymes plays the predominant role in chronic lung injury associated with smoking. Perhaps the greatest advance in the emphysema field in recent years involves new discoveries concerning the structure and function of the alpha-1-proteinase (elastase) inhibitor. Applications of recombinant DNA technology and genetic engineering have made it possible to design modified inhibitors with striking new properties. These agents may enjoy significant clinical application in the not too distant future.

Topics: alpha 1-Antitrypsin; Animals; Blood Platelets; Blood Proteins; Disease Models, Animal; Elastin; Fibroblasts; Humans; Leukocytes; Lung; Macrophages; Monocytes; Muscle, Smooth; Neutrophils; Pancreatic Elastase; Pulmonary Emphysema; Respiratory System; Smoking

Topics: Animals; Cadmium; Collagen; Connective Tissue; Disease Models, Animal; Elastin; Humans; Lung; Lung Compliance; Lung Volume Measurements; Nitrogen Dioxide; Pancreatic Elastase; Papain; Phosgene; Pulmonary Alveoli; Pulmonary Circulation; Pulmonary Emphysema; Smoking

Topics: Animals; Brain Diseases; Copper; Deficiency Diseases; Disease Models, Animal; Elastin; Electron Transport Complex IV; Female; Growth; Heart Diseases; Pregnancy; Pregnancy Complications; Rats

We have been concerned in the first section of this review with those diseases that are aging processes, or appear to be so. Some of these (e.g., cardiovascular, pulmonary, neoplasia) cause the death of a large proportion of animals, while others (e.g., osteoporosis, amyloidosis), though clearly progressive with age, are nonfatal. Many diverse factors influence the normal process of aging. Restriction of dietary caloric intake prolongs lifespan and decreases the incidence and severity of diseases associated with aging, probably by depressing anterior pituitary gland function...

Topics: Aging; Animals; Antioxidants; Cells; Collagen; Diet; Disease Models, Animal; Elastin; Hormones; Humans; Immune System Diseases; Mice; Models, Biological; Pigmentation; Progeria; Radiation Effects; Rats; Stress, Physiological; Stress, Psychological; Vitamin D

Topics: Animals; Arteries; Arteriosclerosis; Autoradiography; Collagen; Disease Models, Animal; DNA; Elastin; Endothelium; Female; Glycosaminoglycans; Histocytochemistry; Humans; In Vitro Techniques; Lipid Metabolism; Polysaccharides; Proteins; Proteoglycans; Solubility; Staining and Labeling; Thymidine; Tritium; Vascular Diseases

Topics: Animals; Arteriosclerosis; Blood Platelets; Blood Vessels; Calcium; Cell Division; Cell Membrane Permeability; Collagen; Disease Models, Animal; Elastin; Endothelium; Fibrin; Glycosaminoglycans; Histocytochemistry; Humans; Lipid Metabolism; Microscopy, Electron; Necrosis; Platelet Adhesiveness

Medical therapeutic options to prevent rupture of abdominal aortic aneurysm (AAA), a critical event, must be developed. Moreover, further understanding of the process of AAA development and rupture is crucial. Previous studies have revealed that aortic hypoperfusion can induce the development of AAA, and we successfully developed a hypoperfusion-induced AAA animal model. In this study, we examined the effects of medium-chain triglycerides (MCTs), tricaprylin (C8-TG) and tricaprin (C10-TG), on hypoperfusion-induced AAA rat model. We estimated the effects of MCTs on aortic pathologies, mechanical properties of the aorta, and development of AAA. C10-TG, but not C8-TG, significantly suppressed AAA development and completely prevented the rupture. We observed that C10-TG prevented the development and rupture of AAA, but not C8-TG. Additionally, regression of AAA diameter was observed in the C10-TG group. Pathological analysis revealed C10-TG improved the hypoperfusion-induced increase in hypoxia-inducible factor-1α levels, medial smooth muscle cells (SMCs) loss, degeneration of aortic elastin and collagen fibers, and loss of aortic wall elasticity. In addition, regression of the formed AAA was observed by administration of C10-TG after AAA formation. C10-TG administration after AAA formation improved degeneration of AAA wall including degradation of aortic elastin and collagen fibers, stenosis of vasa vasorum, and loss of medial SMCs. These data suggest C10-TG can prevent AAA by attenuating aortic hypoperfusion and degeneration. Considering the clinical safety of C10-TG, C10-TG can be a promising AAA drug candidate.

Topics: Animals; Aorta, Abdominal; Aortic Aneurysm, Abdominal; Collagen; Disease Models, Animal; Elastin; Rats; Triglycerides

For decades, numerous experimental animal models have been developed to examine the pathophysiologic mechanisms and potential treatments for abdominal aortic aneurysms (AAAs) in diverse species with varying chemical or surgical approaches. This study aimed to create an AAA mouse model by the periarterial incubation with papain, which can mimic human AAA with advantages such as simplicity, convenience, and high efficiency. Eighty C57BL/6J male mice were randomly assigned to 1 of the 4 groups: papain (1.0 or 2.0 mg), porcine pancreatic elastase, and phosphate-buffered solution. The aortic segment was wrapped for 20 minutes, and the diameter was measured using ultrasound preoperatively and postoperative days 7 and 14. Then, the mice were killed for histomorphometric and immunohistochemical analyses. According to ultrasound measurements and histomorphometric analyses, on postoperative day 7, 65% of mice in the 1.0-mg papain group and 60% of mice in the 2.0-mg papain group developed AAA. In both papain groups, 100% of mice developed AAA, and 65% of mice in the porcine pancreatic elastase group developed AAA on postoperative day 14. Furthermore, hematoxylin/eosin, elastin van Gieson, and Masson staining of tissues from the papain group revealed thickened media and intimal hyperplasia, collagen sediments, and elastin destruction, indicating that AAA histochemical alteration was similar to that of humans. In addition, the immunohistochemical analysis was conducted to detect infiltrated inflammatory cells, such as macrophages and leukocytes, in the aortic wall and hyperplasic adventitia. The expression of matrix metalloproteinase 2 and 9 was significantly upregulated in papain and human AAA tissues. Periarterial incubation with 1.0 mg of papain for 20 minutes can successfully create an experimental AAA model in mice for 14 days, which can be used to explore the mechanism and treatment of human AAA.

Topics: Animals; Aorta, Abdominal; Aortic Aneurysm, Abdominal; Disease Models, Animal; Elastin; Humans; Male; Matrix Metalloproteinase 2; Mice; Mice, Inbred C57BL; Pancreatic Elastase; Papain; Swine

Abdominal aortic aneurysm (AAA) is a multifactorial cardiovascular disease with a high risk of death, and it occurs in the infrarenal aorta with vascular dilatation. High blood pressure acts on the aortic wall, resulting in rupture and causing life-threatening intra-abdominal hemorrhage. Vascular smooth muscle cell (VSMC) dysregulation and extracellular matrix (ECM) degradation, especially elastin breaks, contribute to structural changes in the aortic wall. The pathogenesis of AAA includes the occurrence of oxidative stress, inflammatory cell infiltration, elastic fiber fragmentation, VSMC apoptosis, and phenotypic transformation. Tributyrin (TB) is decomposed by intestinal lipase and has a function similar to that of butyrate. Whether TB has a protective effect against AAA remains uncertain. In the present study, we established an AAA murine model by angiotensin II (AngII) induction in low-density lipoprotein receptor knockout (

Topics: Angiotensin II; Animals; Aorta, Abdominal; Aortic Aneurysm, Abdominal; Disease Models, Animal; Elastin; Epigenesis, Genetic; Humans; Mice; Mice, Inbred C57BL; Mice, Knockout

Williams-Beuren syndrome (WBS) is a rare neurodevelopmental disorder that, together with a rather characteristic neurocognitive profile, presents a strong cardiovascular phenotype. The cardiovascular features of WBS are mainly related to a gene dosage effect due to hemizygosity of the elastin (

Topics: Animals; Disease Models, Animal; Elastin; Mice; Mitochondria; Phenotype; Williams Syndrome

Structural, functional and molecular cardiac defects have been reported in spinal muscular atrophy (SMA) patients and mouse models. Previous quantitative proteomics analyses demonstrated widespread molecular defects in the severe Taiwanese SMA mouse model. Whether such changes are conserved across different mouse models, including less severe forms of the disease, has yet to be established. Here, using the same high-resolution proteomics approach in the less-severe Smn2B/- SMA mouse model, 277 proteins were found to be differentially abundant at a symptomatic timepoint (post-natal day (P) 18), 50 of which were similarly dysregulated in severe Taiwanese SMA mice. Bioinformatics analysis linked many of the differentially abundant proteins to cardiovascular development and function, with intermediate filaments highlighted as an enriched cellular compartment in both datasets. Lamin A/C was increased in the cardiac tissue, whereas another intermediate filament protein, desmin, was reduced. The extracellular matrix (ECM) protein, elastin, was also robustly decreased in the heart of Smn2B/- mice. AAV9-SMN1-mediated gene therapy rectified low levels of survival motor neuron protein and restored desmin levels in heart tissues of Smn2B/- mice. In contrast, AAV9-SMN1 therapy failed to correct lamin A/C or elastin levels. Intermediate filament proteins and the ECM have key roles in cardiac function and their dysregulation may explain cardiac impairment in SMA, especially since mutations in genes encoding these proteins cause other diseases with cardiac aberration. Cardiac pathology may need to be considered in the long-term care of SMA patients, as it is unclear whether currently available treatments can fully rescue peripheral pathology in SMA.

Topics: Animals; Desmin; Disease Models, Animal; Elastin; Genetic Therapy; Humans; Lamin Type A; Mice; Motor Neurons; Muscular Atrophy, Spinal; Survival of Motor Neuron 1 Protein

We aimed to investigate the formation and self-healing process of rabbit abdominal aortic aneurysm (AAA) by focus on the degeneration and regeneration of smooth muscle cells (SMCs) in elastase-induced AAA model and enlarging AAA model in rabbits.. Sixty rabbits were equally divided into 2 aneurysm groups (Group A and Group B). Rabbits received a 10-min incubation of elastase in Group A (10 units/µL) and Group B (1 unit/µL). Rabbits underwent aortic stenosis above the incubated segment in Group B. Aortic diameter was measured and rabbits were sacrificed for histopathological and immunohistochemical studies.. The incubated aorta dilated immediately and ran up to maxima by day 21 in Group A. All aneurysms formed by day 21 and enlarged progressively in Group B. SMCs content, elastin content and intima-media thickness decreased significantly by day 0 in Group A. SMCs and elastic fibers were destroyed gradually in Group B, however, SMCs content was significantly lower than Group A by day 70. Intimal thickness increased significantly by day 70 in the Aneurysm groups. MMP2 maintained moderate expression in Group A, which decreased significantly by day 3 in Group B. MMP9 and RAM11 expressions were higher by day 1, but decreased significantly by day 3 in Group B.. Irreversible degeneration of SMCs is critical to a rapid formation of elastase-induced rabbit AAA model, and SMCs excessive regeneration accounts for the selfhealing process. SMCs degradation and regeneration remain relatively stable in an enlarging AAA model. SMCs should be the key target for studying the mechanism of AAA and intervention therapy.

Topics: Animals; Aorta, Abdominal; Aortic Aneurysm, Abdominal; Dilatation, Pathologic; Disease Models, Animal; Elastic Tissue; Elastin; Ligation; Male; Matrix Metalloproteinase 2; Matrix Metalloproteinase 9; Muscle, Smooth, Vascular; Myocytes, Smooth Muscle; Pancreatic Elastase; Rabbits; Regeneration; Time Factors; Vascular Remodeling

Background cGMP-hydrolyzing phosphodiesterase type 5 (PDE5) regulates vascular smooth muscle cell (SMC) contraction by antagonizing cGMP-dependent protein kinase I (PKGI)-dependent SMC relaxation. SMC contractile dysfunction is implicated in the pathogenesis of aortic aneurysm. PDE5 inhibitors have been used for treating erectile dysfunction, such as drug Viagra (sildenafil). However, a few clinical cases have reported the association of Viagra usage with aortic dissection, and reduced PDE5A expression was found in human aortic aneurysm tissues. Therefore, we aimed to investigate the effect of sildenafil on experimental abdominal aortic aneurysm (AAA), the most common form of aortic aneurysm in elderly men. Methods and Results AAA was induced in C57BL/6J male mice by periaortic elastase in combination with blocking elastin/collagen formation via 3-aminopropionitrile fumarate salt for 35 days. PDE5A protein levels detected by immunostaining were significantly reduced in mouse AAA. Sildenafil application in drinking water significantly aggravated aortic wall dilation and elastin degradation with pre-existing moderate AAA. The phosphorylation level of myosin light chain 2 at Ser19, a biochemical marker of SMC contraction, was significantly reduced by sildenafil in AAA. Proximity ligation assay further revealed that the interaction between cGMP and PKGI was significantly increased by sildenafil in AAA, suggesting an elevation of PKGI activation in AAA. Conclusions Sildenafil treatment aggravated the degradation of elastin fibers and progression of experimental AAA by dysregulating cGMP and contractile signaling in SMCs. Our findings may raise the caution of clinical usage of Viagra in aneurysmal patients.

Topics: Aged; Animals; Aorta, Abdominal; Aortic Aneurysm, Abdominal; Disease Models, Animal; Elastin; Humans; Male; Mice; Mice, Inbred C57BL; Sildenafil Citrate

Marfan syndrome (MFS) is associated with TGF (transforming growth factor) β-stimulated ERK (extracellular signal-regulated kinase) activity in vascular smooth muscle cells (VSMCs), which adopt a mixed synthetic/contractile phenotype. In VSMCs, TGFβ induces IL (interleukin) 11) that stimulates ERK-dependent secretion of collagens and MMPs (matrix metalloproteinases). Here, we examined the role of IL11 in the MFS aorta.. We used echocardiography, histology, immunostaining, and biochemical methods to study aortic anatomy, physiology, and molecular endophenotypes in. In MFS, IL11 is upregulated in aortic VSMCs to cause ERK-related thoracic aortic dilatation, inflammation, and fibrosis. Therapeutic inhibition of IL11, imminent in clinical trials, might be considered as a new approach in MFS.

Topics: Animals; Antibodies, Neutralizing; Aorta; Aortic Diseases; Disease Models, Animal; Elastin; Fibrosis; Immunoglobulin G; Inflammation; Interleukin-11; Interleukin-11 Receptor alpha Subunit; Marfan Syndrome; Matrix Metalloproteinase 2; Mice; Muscle, Smooth, Vascular; Receptors, Interleukin-11; Transforming Growth Factor beta

The leading cause of mortality in patients with Marfan syndrome (MFS) is thoracic aortic aneurysm and dissection. Notch signaling is essential for vessel morphogenesis and function. However, the role of Notch signaling in aortic pathology and aortic smooth muscle cell (SMC) differentiation in Marfan syndrome (MFS) is not completely understood.. RNA-sequencing on ascending aortic tissue from a mouse model of MFS,. The murine RNA-sequencing data were validated with mouse and human MFS aortic tissue, demonstrating elevated Notch3 activation in MFS. Data further revealed that upregulation and activation of Notch3 were concomitant with increased expression of SMC contractile markers. Inhibiting Notch3 activation with DAPT attenuated aortic enlargement and improved survival of. Our data demonstrated that matrix abnormalities in the aorta of MFS are associated with increased Notch3 activation. Enhanced Notch3 activation in MFS contributed to aortic aneurysm formation in MFS. This might be mediated by inducing a contractile phenotypic change of SMC. Our results suggest that inhibiting Notch3 activation may provide a strategy to prevent and treat aortic aneurysms in MFS.

Topics: Animals; Aorta; Aortic Aneurysm; Diamines; Disease Models, Animal; Elastin; Fibrillin-1; Humans; Marfan Syndrome; Mice; Mice, Inbred C57BL; Mice, Mutant Strains; Molecular Targeted Therapy; Myocytes, Smooth Muscle; Receptor, Notch3; Thiazoles

The aim of this study was to compare and characterize the structural and ultrastructural organization of the temporomandibular joint (TMJ) between two large animal models for use in the development of tissue engineering strategies.. Whole TMJs from sheep and pigs were evaluated with micro-computed tomography (μCT) for morphology and quantitative analyses of bone parameters. Histological examination was performed on the TMJ disc and its attachments to investigate regional distribution of collagen, elastin, and glycosaminoglycans (GAGs).. μCT analyses demonstrate higher bone mineral density (BMD) in the temporal fossa compared to the mandibular condyle in both species, with this variable being significantly higher in sheep than pig. Quantitative morphometry of the trabecular condyle reveals no statistical differences between the species. Histology demonstrates similar structural organization of collagen and elastin between species. Elastin staining was nearly twofold greater in sheep than in the pig disc. Finally, Safranin-O staining for GAGs in the TMJ disc was localized to the intermediate zone in the sheep but was absent from the porcine disc.. Our findings show some important differences in the pig and sheep TMJ μCT variables and histology and composition of the disc and discal attachment. These disparities likely reflect differences in masticatory and TMJ functional loading patterns between the two species and provide insights into large animal models towards human applications.. As with the established pig model, the sheep is a suitable large animal model for TMJ research such as regenerative strategies, with specific considerations for design parameters appropriate for human-analog applications.

Topics: Animals; Collagen; Disease Models, Animal; Elastin; Glycosaminoglycans; Humans; Mandibular Condyle; Sheep; Swine; Temporomandibular Joint; Temporomandibular Joint Disorders; Tissue Engineering; X-Ray Microtomography

Background The biological mechanism of action for osteoprotegerin, a soluble decoy receptor for the receptor activator of nuclear factor-kappa B ligand in the vascular structure, has not been elucidated. The study aim was to determine if osteoprotegerin affects aortic structural integrity in angiotensin II (Ang II)-induced hypertension. Methods and Results Mortality was higher (

Topics: Angiotensin II; Animals; Aortic Dissection; Aortic Rupture; Disease Models, Animal; Elastin; Hypertension; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Osteoprotegerin; RANK Ligand

Balloon angioplasty, stent implantation, and application of an arterial clamp during surgery can induce artery injury such as elastin breaks and endothelium injury, but there is little research focused on the injury induced by these therapeutic manipulations. We established a simple and reproducible small animal aortic injury model and examined intramural injection as a potential therapeutic method to alleviate injury.. The abdominal aorta of male Sprague Dawley (SD) rats or C57BL/6 J mice was clamped sequentially throughout its length. Transforming growth factor β1 (TGFβ1), SB431542, lipopolysaccharide (LPS), Necrostatin-1 (Nec-1), rapamycin, or MHY1485 contained in Pluronic gel was injected intramurally at day 0 or day 7. Animals were fed with chow containing 0.25% beta-aminopropionitrile (BAPN) to evaluate the influence of BAPN. All samples were harvested and examined by immunohistochemistry and immunofluorescence.. The clamped rat aorta showed luminal dilation, elastin fiber breaks, neointimal hyperplasia, and dissection (days 0-90). Intramural injection of TGFβ1, rapamycin and Nec-1 showed a protective effect on the injured aorta, whereas SB431542, MHY1485 and LPS showed more severe wall damage. The aortic lumen in rats fed with BAPN was significantly larger than in control rats (day 7). Mouse aorta showed similar injury with neointimal hyperplasia and elastin fiber breaks.. The rodent arterial injury model is reproducible and may mimic early changes of arterial injury. The model accommodates intramural injection of different drugs that may show mechanisms of arterial injury. Although this is a preliminary animal model, the intramural injection method may have potential clinical application in the future.

Topics: Aminopropionitrile; Animals; Aorta, Abdominal; Disease Models, Animal; Elastin; Hyperplasia; Lipopolysaccharides; Male; Mice; Mice, Inbred C57BL; Neointima; Poloxamer; Rats; Rats, Sprague-Dawley; Sirolimus

Interleukin-1 (IL-1) signaling has an established role as a cytokine signaling pathway important for progression of abdominal aortic aneurysms (AAAs). While the IL-1β ligand and IL-1R1 have been previously investigated, the role of the IL-1α ligand in AAAs remains unknown. In this study, we sought to examine the role of IL-1α in AAAs using genetic and pharmacologic approaches.. Eight-week-old wild-type (WT) or IL-1α knock-out (KO) male and female mice (n = 10-16/group) underwent experimental AAA and were harvested 14 days following surgery to assess AAA size and characteristics. In separate studies, 8-week-old WT mice were treated with an inhibitor to IL-1α during AAA formation and harvested 14 days following surgery. Finally, WT and IL-1α KO mice were administered Anakinra, an IL-R1 inhibitor, during AAA formation to determine the effect of inhibiting IL-1R1 when IL-1α is knocked out.. Male and female IL-1α KO mice had larger AAAs compared to WT AAAs (male: 153% vs. 89.2%, P = 0.0001; female: 86.6% vs. 63.5%, P = 0.02). IL-1α KO mice had greater elastin breakage (P = 0.01), increased levels of macrophage staining (P = 0.0045), and greater pro-metallo proteinase 2 (P = 0.02). Pharmacologic inhibition of WT male mice with an IL-1α neutralizing antibody resulted in larger AAAs (133.1% vs. 77.0%, P < 0.001). Finally, treatment of IL-1α KO male mice with Anakinra decreased AAA formation compared with vehicle control AAAs (Anakinra + IL-1α KO: 47.7% vs. WT: 147.1%; P = 0.0001).. IL-1α disruption using either genetic or pharmacologic approaches worsens AAAs.

Topics: Animals; Antibodies, Neutralizing; Aorta, Abdominal; Aortic Aneurysm, Abdominal; Disease Models, Animal; Elastin; Female; Interleukin 1 Receptor Antagonist Protein; Interleukin-1alpha; Ligands; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Peptide Hydrolases; Treatment Outcome

Fluoroquinolones are one of the most frequently prescribed antibiotics. However, their use increases the risk of Aortic aneurysm and dissection (AAD). The mechanism underlying this effect remains unclear. AAD are caused by weakening of the aortic wall and loss of vascular smooth muscle cells. Osteopontin is involved in the occurrence and development of AAD. The aim of the present study was to examine the role of moxifloxacin, a fluoroquinolone, in the occurrence of AAD using a moderate-severity AAD mouse model. Four-week-old male C57BL/6J mice were fed a high-fat diet. At 8 weeks of age, the mice were infused with saline or angiotensin II (1000 ng kg

Topics: Angiotensin II; Animals; Anti-Bacterial Agents; Aortic Aneurysm; Aortic Dissection; Disease Models, Animal; Elastin; Eosine Yellowish-(YS); Hematoxylin; Male; Matrix Metalloproteinase 2; Mice; Mice, Inbred C57BL; Moxifloxacin; Muscle Proteins; Myocytes, Smooth Muscle; Osteopontin; Rubber; Water

Abdominal aortic aneurysm (AAA) represents the serious vascular degenerative disorder, which causes high incidence and mortality. Alpha-ketoglutarate (AKG), a crucial metabolite in the tricarboxylic acid (TCA) cycle, has been reported to exert significant actions on the oxidative stress and inflammation. However, its role in AAA still remains elusive. Herein, we examined the effects of AKG on the formation of AAA. The study established an elastase-induced mouse abdominal aortic aneurysms model as well as a TNF-α-mediated vascular smooth muscle cells (VSMCs) model, respectively. We displayed that AKG pre-treatment remarkably prevented aneurysmal dilation assessed by diameter and volume and reduced aortic rupture. In addition, it was also observed that AKG treatment suppressed the development of AAA by attenuating the macrophage infiltration, elastin degradation and collagen fibers remodeling. In vitro, AKG potently decreased TNF-α-induced inflammatory cytokines overproduction, more apoptotic cells and excessive superoxide. Mechanistically, we discovered that upregulation of vpo1 in AAA was significantly suppressed by AKG treatment. By exploring the RNA-seq data, we found that AKG ameliorates AAA mostly though inhibiting oxidative stress and the inflammatory response. PXDN overexpression neutralized the inhibitory effects of AKG on ROS generation and inflammatory reaction in MOVAS. Furthermore, AKG treatment suppressed the expression of p-ERK1/2, 3-Cl Tyr in vivo and in vitro. ERK activator disrupted the protective of AKG on TNF-α-induced VSMCs phenotypic switch. Conclusively, AKG can serve as a beneficial therapy for AAA through regulating PXDN/HOCL/ERK signaling pathways.

Topics: Animals; Aortic Aneurysm, Abdominal; Collagen; Cytokines; Deoxyribonucleosides; Disease Models, Animal; Elastin; Inflammation; Ketoglutaric Acids; MAP Kinase Signaling System; Mice; Mice, Inbred C57BL; Muscle, Smooth, Vascular; Myocytes, Smooth Muscle; Pancreatic Elastase; Purine Nucleosides; Reactive Oxygen Species; Signal Transduction; Superoxides; Tricarboxylic Acids; Tumor Necrosis Factor-alpha

Aortic dissection (AD) is a lethal aortic pathology without effective medical treatments since the underlying pathological mechanisms responsible for AD remain elusive. Matrix metalloproteinase-8 (MMP8) has been previously identified as a key player in atherosclerosis and arterial remodeling. However, the functional role of MMP8 in AD remains largely unknown. Here, we report that an increased level of MMP8 was observed in 3-aminopropionitrile fumarate (BAPN)-induced murine AD. AD incidence and aortic elastin fragmentation were markedly reduced in MMP8-knockout mice. Importantly, pharmacologic inhibition of MMP8 significantly reduced the AD incidence and aortic elastin fragmentation. We observed less inflammatory cell accumulation, a lower level of aortic inflammation, and decreased smooth muscle cell (SMC) apoptosis in MMP8-knockout mice. In line with our previous observation that MMP8 cleaves Ang I to generate Ang II, BAPN-treated MMP8-knockout mice had increased levels of Ang I, but decreased levels of Ang II and lower blood pressure. Additionally, we observed a decreased expression level of vascular cell adhesion molecule-1 (VCAM1) and a reduced level of reactive oxygen species (ROS) in MMP8-knockout aortas. Mechanistically, our data show that the Ang II/VCAM1 signal axis is responsible for MMP8-mediated inflammatory cell invasion and transendothelial migration, while MMP8-mediated SMC inflammation and apoptosis are attributed to Ang II/ROS signaling. Finally, we observed higher levels of aortic and serum MMP8 in patients with AD. We therefore provide new insights into the molecular mechanisms underlying AD and identify MMP8 as a potential therapeutic target for this life-threatening aortic disease.

Topics: Aminopropionitrile; Angiotensin II; Animals; Aortic Dissection; Disease Models, Animal; Elastin; Humans; Inflammation; Matrix Metalloproteinase 8; Mice; Mice, Knockout; Reactive Oxygen Species; Vascular Cell Adhesion Molecule-1

Type I interferon receptor signaling contributes to several autoimmune and vascular diseases such as lupus, atherosclerosis and stroke. The purpose of this study was to assess the influence of type I interferon receptor deficiency on the formation and progression of experimental abdominal aortic aneurysms (AAAs).. AAAs were induced in type I interferon receptor subunit 1 (IFNAR1)-deficient and wild type control male mice via intra-infrarenal aortic infusion of porcine pancreatic elastase. Immunostaining for IFNAR1 was evaluated in experimental and clinical aneurysmal abdominal aortae. The initiation and progression of experimental AAAs were assessed via ultrasound imaging prior to (day 0) and days 3, 7 and 14 following elastase infusion. Aneurysmal histopathology was analyzed at sacrifice.. Increased aortic medial and adventitial IFNAR1 expression was present in both clinical AAAs harvested at surgery and experimental AAAs. Following AAA induction, wild type mice experienced progressive, time-dependent infrarenal aortic enlargement. This progression was substantially attenuated in IFNAR1-deficient mice. On histological analyses, medial elastin degradation, smooth muscle cell depletion, leukocyte accumulation and neoangiogenesis were markedly diminished in IFNAR1-deficient mice in comparison to wild type mice.. IFNAR1 deficiency limited experimental AAA progression in response to intra-aortic elastase infusion. Combined with clinical observations, these results suggest an important role for IFNAR1 activity in AAA pathogenesis.

Topics: Animals; Aortic Aneurysm, Abdominal; Disease Models, Animal; Elastin; Male; Mice; Mice, Inbred C57BL; Pancreatic Elastase; Receptor, Interferon alpha-beta; Swine

Marfan syndrome (MFS) is a connective tissue disorder caused by mutations in the Fibrillin-1 gene. It is associated with formation of thoracic aortic aneurysms that can potentially be a life-threatening condition due to aortic rupture or dissection. Excessive non-canonical transforming growth factor beta signalling, mediated by activation of extracellular signal-regulated kinases 1/2 (ERK1/2), as well as inducible nitric oxide synthase (NOS2)-dependent nitric oxide production, have been identified to drive aortic pathology in MFS through induction of elastin fragmentation and smooth muscle cell apoptosis. Despite promising results in animal studies, specific pharmacological interventions approved for clinical use in patients with MFS-related aortic disease are rare. Nitro-oleic acid (NO2-OA) is an endogenously generated signalling modulator, which is available as an oral compound and has been shown to inhibit ERK1/2 activation and NOS2 expression in different disease models, thereby exerting promising therapeutic effects. In this study, we investigated whether NO2-OA decreases aortic dilation in MFS.. Eight-week-old MFS (Fbn1C1041G/+) mice were treated with NO2-OA or vehicle for 4 weeks via subcutaneously implanted osmotic minipumps. Echocardiography indicated progressive ascending aortic dilation and wall stiffening in MFS mice, which was significantly attenuated by NO2-OA treatment. This protective effect was mediated by inhibition of aortic ERK1/2, Smad2 as well as nuclear factor kappa B overactivation and consequent attenuation of elastin fragmentation by matrix metalloproteinase 2, apoptosis, and collagen deposition. Critically, the therapeutic efficacy of NO2-OA in MFS was further emphasized by demonstrating its capability to reduce lethal aortic complications in Fbn1C1041G/+ mice challenged with Angiotensin II.. NO2-OA distinctly attenuates progression of aortic dilation in MFS via modulation of well-established disease-mediating pathways, thereby meriting further investigation into its application as a therapeutic agent for the treatment of this condition.

Topics: Animals; Aortic Aneurysm; Aortic Aneurysm, Thoracic; Aortic Diseases; Disease Models, Animal; Elastin; Fibrillin-1; Marfan Syndrome; Matrix Metalloproteinase 2; Mice; Nitro Compounds; Oleic Acids

Age-related macular degeneration (AMD), the leading cause of blindness in western populations, is associated with an overactive complement system, and an increase in circulating antibodies against certain epitopes, including elastin. As loss of the elastin layer of Bruch's membrane (BrM) has been reported in aging and AMD, we previously showed that immunization with elastin peptide oxidatively modified by cigarette smoke (ox-elastin), exacerbated ocular pathology in the smoke-induced ocular pathology (SIOP) model. Here we asked whether ox-elastin peptide-based immunotherapy (PIT) ameliorates damage.. Elimination of Fcγ receptors, preventing antigen/antibody-dependent cytotoxicity, protected against SIOP. Mice receiving PIT with low dose ox-elastin (LD-PIT) exhibited reduced humoral immunity, reduced complement activation and IgG/IgM deposition in the RPE/choroid, and largely a preserved BrM. While there is no direct evidence of ox-elastin pathogenicity, LD-PIT reduced IFNγ and increased IL-4 within RPE/choroid. High dose PIT was not protective.. These data further support ox-elastin role in ocular damage in part via elastin-specific antibodies, and support the corollary that PIT with ox-elastin attenuates ocular pathology. Overall, damage is associated with complement activation, antibody-dependent cell-mediated cytotoxicity, and altered cytokine signature.

Topics: Animals; Cigarette Smoking; Complement Activation; Disease Models, Animal; Elastin; Immunotherapy; Macular Degeneration; Mice; Mice, Inbred C57BL; Microscopy, Electron; Peptides; Receptors, IgG; Retinal Pigment Epithelium; Smoke

Abdominal aortic aneurysm (AAA) is a significant medical problem with a high mortality rate. Nevertheless, the underlying mechanism for the progression and regression of AAA is unknown.. Experimental model of AAA was first created by porcine pancreatic elastase incubation around the infrarenal aorta of C57BL/6 mice. Then, AAA progression and regression were evaluated based on the diameter and volume of AAA. The aortas were harvested for hematoxylin-eosin staining (HE), orcein staining, sirius red staining, immunofluorescence analysis and perls' prussian blue staining at the indicated time point. Finally, β-aminopropionitrile monofumarate (BAPN) was used to explore the underlying mechanism of the regression of AAA.. When we extended the observation period to 100 days, we not only observed an increase in the AAA diameter and volume in the early stage, but also a decrease in the late stage. Consistent with AAA diameter and volume, the aortic thickness showed the same tendency based on HE staining. The elastin and collagen content first degraded and then regenerated, which corresponds to the early deterioration and late regression of AAA. Then, endogenous up-regulation of lysyl oxidase (LOX) was detected, accompanying the regression of AAA, as detected by an immunofluorescent assay. BAPN and LOX inhibitor considerably inhibited the regression of AAA, paralleling the degradation of elastin lamella and collagen.. Taken together, we tentatively conclude that endogenous re-generation of LOX played an influential role in the regression of AAA. Therefore, regulatory factors on the generation of LOX exhibit promising therapeutic potential against AAA.

Topics: Aminopropionitrile; Animals; Aortic Aneurysm, Abdominal; Collagen; Disease Models, Animal; Disease Progression; Elastin; Extracellular Matrix Proteins; Mice; Mice, Inbred C57BL; Pancreatic Elastase; Protein-Lysine 6-Oxidase; Up-Regulation

Dysfunctional elastin turnover plays a major role in the progression of atherosclerotic plaques. Failure of tropoelastin cross-linking into mature elastin leads to the accumulation of tropoelastin within the growing plaque, increasing its instability. Here we present Gd

Topics: Animals; Atherosclerosis; Contrast Media; Disease Models, Animal; Elastin; Gadolinium; Magnetic Resonance Imaging; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Molecular Structure; Surface Plasmon Resonance; Tropoelastin

[Figure: see text].

Topics: Animals; Disease Models, Animal; Elastin; Endothelial Cells; Female; Humans; Pre-Eclampsia; Pregnancy; Rats; Rats, Sprague-Dawley; Treatment Outcome; Vascular Endothelial Growth Factor B

Elastase-induced abdominal aortic aneurysm (AAA) model is widely used for aneurysmal pathogenesis and translational research. However, temporal alternations in aneurysmal histologies remain unknown. This study is aimed at analyzing temporal immunopathologies of aneurysmal aorta following experimental AAA induction.. Male C57BL/6J mice at the age of 10-14 weeks received intra-aortic infusion of elastase to induce AAAs. Aortic diameters at the baseline and indicated days after AAA induction were measured, and aortae were collected for histopathological analysis.. Aorta diameters increased from 0.52 mm at the baseline levels to 0.99 mm, 1.34 mm, and 1.41 mm at days 7, 14, and 28, respectively, corresponding 90%, 158%, and 171% increases over the baseline level. Average aortic diameters did not differ between days 14 and 28. Severe elastin degradation and smooth muscle cell depletion were found at days 14 and 28 as compared to the baseline and day 7. No difference in the scores of medial elastin and SMC destruction was noted between days 14 and 28. Consistent results were found for leukocyte accumulation, neoangiogenesis, and matrix metalloproteinase expression. Twenty-eight days after AAA induction, all aneurysmal pathologies showed an attenuated trend, although most histopathological parameters did no differ between days 14 and 28.. Our data suggest that almost aneurysmal immunohistopathologies reach maximal 14 days following AAA induction. Analysis of day 14 histologies is sufficient for AAA pathogenesis and translational studies in elastase-induced mouse experimental AAAs.

Topics: Animals; Aorta; Aortic Aneurysm, Abdominal; Disease Models, Animal; Elastin; Humans; Infusions, Intra-Arterial; Male; Matrix Metalloproteinases; Mice; Mice, Inbred C57BL; Myocytes, Smooth Muscle; Neovascularization, Pathologic; Pancreatic Elastase

Topics: Aneurysm; Angiotensin II; Animals; Disease Models, Animal; DNA-Binding Proteins; Elastin; Inflammation; Matrix Metalloproteinases; Mice; Mice, Transgenic; Muscle, Smooth, Vascular; Myocytes, Smooth Muscle; Nerve Tissue Proteins; Oxidative Stress; Receptors, Steroid; Receptors, Thyroid Hormone; Signal Transduction

Marfan syndrome is one of the most common inherited disorders of connective tissue caused by fibrillin-1 mutations, characterized by enhanced transcription factor AP-1 DNA binding activity and subsequently abnormally increased expression and activity of matrix-metalloproteinases (MMPs). We aimed to establish a novel adeno-associated virus (AAV)-based strategy for long-term expression of an AP-1 neutralizing RNA hairpin (hp) decoy oligonucleotide (dON) in the aorta to prevent aortic elastolysis in a murine model of Marfan syndrome.. Using fibrillin-1 hypomorphic mice (mgR/mgR), aortic grafts from young (9 weeks old) donor mgR/mgR mice were transduced ex vivo with AAV vectors and implanted as infrarenal aortic interposition grafts in mgR/mgR mice. Grafts were explanted after 30 days. For in vitro studies, isolated primary aortic smooth muscle cells (SMCs) from mgR/mgR mice were used. Elastica-van-Giesson staining visualized elastolysis, reactive oxygen species (ROS) production was assessed using dihydroethidine staining. RNA F.I.S.H. verified AP-1 hp dON generation in the ex vivo transduced aortic tissue. MMP expression and activity were assessed by western blotting and immunoprecipitation combined with zymography.Transduction resulted in stable therapeutic dON expression in endothelial and SMCs. MMP expression and activity, ROS formation as well as expression of monocyte chemoattractant protein-1 were significantly reduced. Monocyte graft infiltration declined and the integrity of the elastin architecture was maintained. RNAseq analysis confirmed the beneficial effect of AP-1 neutralization on the pro-inflammatory environment in SMCs.. This novel approach protects from deterioration of aortic stability by sustained delivery of nucleic acids-based therapeutics and further elucidated how to interfere with the mechanism of elastolysis.

Topics: Animals; Aorta; Aortic Aneurysm; Cells, Cultured; Dependovirus; Dilatation, Pathologic; Disease Models, Animal; Elastin; Female; Fibrillin-1; Genetic Therapy; Genetic Vectors; Humans; Marfan Syndrome; Matrix Metalloproteinases; Mice, Transgenic; Oligonucleotides; Reactive Oxygen Species; Transcription Factor AP-1; Transduction, Genetic; Vascular Remodeling

Topics: Animals; Biological Products; Blood Pressure; Body Weight; Breast Neoplasms; Capillary Permeability; Disease Models, Animal; Elastin; Female; Gene Expression; Glomerular Filtration Rate; Heterografts; Humans; Hypotension; Mice; Molecular Mimicry; Neovascularization, Pathologic; Neovascularization, Physiologic; Rats; Rats, Sprague-Dawley; Recombinant Fusion Proteins; Renal Insufficiency, Chronic; Swine; Toxicity Tests, Chronic; Vascular Endothelial Growth Factor A; X-Ray Microtomography

Hepatic radiofrequency ablation (RFA) induces a drastic alteration of the biomechanical environment in the peritumoral liver tissue. The resulting increase in matrix stiffness has been shown to significantly influence carcinogenesis and cancer progression after focal RF ablation. To investigate the potential of an elastin-specific MR agent (ESMA) for the assessment of extracellular matrix (ECM) remodeling in the periablational rim following RFA in a VX2 rabbit liver tumor-model, twelve New-Zealand-White-rabbits were implanted in the left liver lobe with VX2 tumor chunks from donor animals. RFA of tumors was performed using a perfused RF needle-applicator with a mean tip temperature of 70 °C. Animals were randomized into four groups for MR imaging and scanned at four different time points following RFA (week 0 [baseline], week 1, week 2 and week 3 after RFA), followed by sacrifice and histopathological analysis. ESMA-enhanced MR imaging was used to assess ECM remodeling. Gadobutrol was used as a third-space control agent. Molecular MR imaging using an elastin-specific probe demonstrated a progressive increase in contrast-to-noise ratio (CNR) (week 3: ESMA: 28.1 ± 6.0; gadobutrol: 3.5 ± 2.0), enabling non-invasive imaging of the peritumoral zone with high spatial-resolution, and accurate assessment of elastin deposition in the periablational rim. In vivo CNR correlated with ex vivo histomorphometry (ElasticaVanGiesson-stain, y = 1.2x - 1.8, R

Topics: Animals; Catheter Ablation; Disease Models, Animal; Elastin; Extracellular Matrix; Female; Gadolinium; Humans; Liver Neoplasms; Magnetic Resonance Imaging; Male; Mass Spectrometry; Molecular Imaging; Postoperative Care; Rabbits; Radiofrequency Ablation

Cigarette smoke (CS)-induced macrophage activation and airway epithelial injury are both critical for the development of chronic obstructive pulmonary disease (COPD), while the eventual functions of autophagy in these processes remain controversial. We have recently developed a novel COPD mouse model which is based on the autoimmune response sensitized by CS and facilitated by elastin. In the current study, we therefore utilized this model to investigate the roles of autophagy in different stages of the development of bronchitis-like airway inflammation. Autophagic markers were increased in airway epithelium and lung tissues, and

Topics: Animals; Autophagy; Biomarkers; Bronchitis; Cell Line; Cells, Cultured; Disease Models, Animal; Disease Susceptibility; Elastin; Gene Expression; Humans; Immunohistochemistry; Lung; Macrophages, Alveolar; Male; Matrix Metalloproteinase 12; Mice; Tobacco Smoke Pollution

Abdominal aortic aneurysms (AAAs) are characterized histopathologically by compromised elastic fiber integrity, lost smooth muscle cells or their function, and remodeled collagen. We used a recently introduced mouse model of AAAs that combines enzymatic degradation of elastic fibers and blocking of lysyl oxidase, and thus matrix cross-linking, to study progressive dilatation of the infrarenal abdominal aorta, including development of intraluminal thrombus. We quantified changes in biomaterial properties and biomechanical functionality within the aneurysmal segment as a function of time of enlargement and degree of thrombosis. Towards this end, we combined multi-modality imaging with state-of-the art biomechanical testing and histology to quantify regional heterogeneities for the first time and we used a computational model of arterial growth and remodeling to test multiple hypotheses, suggested by the data, regarding the degree of lost elastin, accumulation of glycosaminoglycans, and rates of collagen turnover. We found that standard histopathological findings can be misleading, while combining advanced experimental and computational methods revealed that glycosaminoglycan accumulation is pathologic, not adaptive, and that heightened collagen deposition is ineffective if not cross-linked. In conclusion, loss of elastic fiber integrity can be a strong initiator of aortic aneurysms, but it is the rate and effectiveness of fibrillar collagen remodeling that dictates enlargement. STATEMENT OF SIGNIFICANCE: Precise mechanisms by which abdominal aortic aneurysms enlarge remain unclear, but a recent elastase plus β-aminopropionitrile mouse model provides new insight into disease progression. As in the human condition, the aortic degeneration and adverse remodeling are highly heterogeneous in this model. Our multi-modality experiments quantify and contrast the heterogeneities in geometry and biomaterial properties, and our computational modeling shows that standard histopathology can be misleading. Neither accumulating glycosaminoglycans nor frustrated collagen synthesis slow disease progression, thus highlighting the importance of stimulating adaptive collagen remodeling to limit lesion enlargement.

Topics: Aminopropionitrile; Animals; Aorta, Abdominal; Aortic Aneurysm, Abdominal; Disease Models, Animal; Elastic Tissue; Elastin; Mice; Pancreatic Elastase

Pulmonary hypertension (PH) associated with congenital heart disease is a progressive hemodynamic disease that can lead to increased pulmonary vascular resistance, vascular remodeling, and even right heart failure and death. LF3 is a novel inhibitor of the reporter gene activity of β-catenin/TCF4 interaction in the Wnt/β-catenin signal pathway. However, whether this action of LF3 can prevent PH development remains unclear. In this study, we investigated the therapeutic effect of LF3 in rat primary pulmonary artery smooth muscle cells (PASMCs) of the PH model. We found that LF3 inhibited the decrease in pulmonary artery acceleration time and ejection time by ultra-high-resolution ultrasound imaging and blocked the increase of pulmonary artery systolic pressure by using the BL420 biological function experimental system and right ventricular hypertrophy index by the electronic scales. Simultaneously, it prevented the increase of α-smooth muscle actin and fibronectin and the decrease of elastin in pulmonary arteries of rats in the PH group, as revealed by an immunohistochemical analysis. Moreover, cell proliferation and migration assays showed that LF3 significantly reduced the proliferation and migration of PASMCs. Western blotting and quantitative real-time polymerase chain reaction analyses revealed that LF3 suppressed the expression of proliferating cell nuclear antigens and Bcl-2 and increased the expression of Bax but did not alter the expressions of β-catenin and TCF4. Taken together, LF3 can reduce the migration and proliferation of PASMCs and induce their apoptosis to prevent the development of PH. It would be worthwhile to explore the potential use of LF3 in the treatment of PH.

Topics: Actins; Animals; Apoptosis; Benzenesulfonamides; beta Catenin; Cell Movement; Cell Proliferation; Cells, Cultured; Disease Models, Animal; Elastin; Fibronectins; Hemodynamics; Hypertension, Pulmonary; Male; Myocytes, Smooth Muscle; Proliferating Cell Nuclear Antigen; Pulmonary Artery; Rats, Sprague-Dawley; Sulfonamides; Transcription Factor 4; Vascular Remodeling; Wnt Signaling Pathway

The extrahepatic bile duct is the primary tissue initially affected by biliary atresia. Biliary atresia is a cholangiopathy which exclusively affects neonates. Current animal models suggest that the developing bile duct is uniquely susceptible to damage. In this study, we aimed to define the anatomical and functional differences between the neonatal and adult mouse extrahepatic bile ducts.. We studied mouse passaged cholangiocytes, mouse BALB/c neonatal and adult primary cholangiocytes, as well as isolated extrahepatic bile ducts, and a collagen reporter mouse. The methods used included transmission electron microscopy, lectin staining, immunostaining, rhodamine uptake assays, bile acid toxicity assays, and in vitro modeling of the matrix.. The cholangiocyte monolayer of the neonatal extrahepatic bile duct was immature, lacking the uniform apical glycocalyx and mature cell-cell junctions typical of adult cholangiocytes. Functional studies showed that the glycocalyx protected against bile acid injury and that neonatal cholangiocyte monolayers were more permeable than adult monolayers. In adult ducts, the submucosal space was filled with collagen I, elastin, hyaluronic acid, and proteoglycans. In contrast, the neonatal submucosa had little collagen I and elastin, although both increased rapidly after birth. In vitro modeling of the matrix suggested that the composition of the neonatal submucosa relative to the adult submucosa led to increased diffusion of bile. A Col-GFP reporter mouse showed that cells in the neonatal but not adult submucosa were actively producing collagen.. We identified 4 key differences between the neonatal and adult extrahepatic bile duct. We showed that these features may have functional implications, suggesting the neonatal extrahepatic bile ducts are particularly susceptible to injury and fibrosis.. Biliary atresia is a disease that affects newborns and is characterized by extrahepatic bile duct injury and obstruction, resulting in liver injury. We identify 4 key differences between the epithelial and submucosal layers of the neonatal and adult extrahepatic bile duct and show that these may render the neonatal duct particularly susceptible to injury.

Topics: Animals; Animals, Newborn; Bile Ducts, Extrahepatic; Biliary Atresia; Cell Survival; Cells, Cultured; Collagen Type I; Collagen Type I, alpha 1 Chain; Disease Models, Animal; Elastin; Epithelial Cells; Female; Green Fluorescent Proteins; Humans; Hyaluronic Acid; Immunohistochemistry; Intercellular Junctions; Male; Mice; Mice, Inbred BALB C; Microscopy, Electron, Transmission; Mucous Membrane; Proteoglycans

The most common injury of preterm infants is periventricular leukomalacia (PVL) and to date there is still no safe and effective treatment. In our previous studies, leptin has been found to have neuroprotective effects on the preterm ischemia-hypoxia brain damage model rats in animal behavior. To gain insight into the neuroprotective mechanisms of leptin on preterm brain damage model rats, we constructed a comparative peptidomic profiling of hippocampal tissue between leptin-treated after model and preterm ischemia-hypoxia brain damage model rats using a stable isobaric labeling strategy involving tandem mass tag reagents, followed by nano liquid chromatography tandem mass spectrometry. We identified and quantified 4164 peptides, 238 of which were differential expressed in hippocampal tissue in the two groups. A total of 150 peptides were up regulated and 88 peptides were down regulated. These peptides were imported into the Ingenuity Pathway Analysis (IPA) and identified putative roles in nervous system development, function and diseases. We concluded that the preterm ischemia-hypoxia brain damage model with leptin treatment induced peptides changes in hippocampus, and these peptides, especially for the peptides associated "microtubule-associated protein 1b (MAP1b), Elastin (Eln), Piccolo presynaptic cytomatrix protein (Pclo), Zinc finger homeobox 3(Zfhx3), Alpha-kinase 3(Alpk3) and Myosin XVA(Myo15a) ", could be candidate bio-active peptides and participate in neuroprotection of leptin. These may advance our current understanding of the mechanism of leptin's neuroprotective effect on preterm brain damage and may be involved in the etiology of preterm brain damage. Meanwhile, we found that repression of ILK signaling pathway plays a significant role in neuroprotection of leptin. A better understanding of the role of ILK signaling pathway in neuroprotective mechanisms will help scientists and researchers to develop selective, safe and efficacious drug for therapy against human nervous system disorders.

Topics: Animals; Animals, Newborn; Brain; Carotid Artery, Common; Cytoskeletal Proteins; Disease Models, Animal; Elastin; Hippocampus; Homeodomain Proteins; Hypoxia-Ischemia, Brain; Leptin; Leukomalacia, Periventricular; Ligation; Microtubule-Associated Proteins; Myosins; Neuropeptides; Neuroprotective Agents; Peptides; Protein Serine-Threonine Kinases; Rats; Signal Transduction

Structural changes in collagen and elastin fiber density have been previously evaluated by qualitative histological studies; however, quantitative evaluations are lacking.. To evaluate quantitative changes in collagen and elastin fibers in the vaginal wall in a porcine model after volumetric radiofrequency heating with an intravaginal applicator.. An animal model was used (domestic pig, multipara: 5.67 ± 0.94 deliveries, 3 years of age). Three pigs under general anesthesia were treated (8-minute, vaginal canal area) once per week for the course of three weeks. There were 2 follow-up evaluations at one and four weeks. Histology specimens were obtained via punch biopsy under ultrasound control. Ultrasound video measurements of the vaginal wall thickness were also obtained. Tissue samples were stained by H&E as well as stains for collagen and elastin fibers.. Elastin (P < .001) and collagen (P < .01) fiber density increased after every treatment. The measured increase in fibers was highest at the one-week follow-up. Elastin accounted on average for 51.46 ± 16.86% of the tissue examined (increase of 36.8% points), while collagen accounted on average for 44.83 ± 18.92% (increase of 17.1% points). The number of synthetically active cells was increased by 16%. While vaginal wall thickness did show an increase of 1.66 mm (32%), this tendency was not statistically significant (P > .05).. Results suggest that volumetric heating of vaginal tissue produced quantitative improvement in the connective tissue organization in a porcine study. Neocollagenesis and neoelastogenesis were observed with an increased number of synthetically active cells.

Topics: Animals; Collagen; Connective Tissue; Disease Models, Animal; Elastin; Female; Radiofrequency Therapy; Sus scrofa; Vagina; Vaginal Diseases

Overactivated B cells secrete pathological antibodies, which in turn accelerate the formation of abdominal aortic aneurysms (AAAs). Hyperhomocysteinaemia (HHcy) aggravates AAA in mice; however, the underlying mechanisms remain largely elusive. In this study, we further investigated whether homocysteine (Hcy)-activated B cells produce antigen-specific antibodies that ultimately contribute to AAA formation.. ELISA assays showed that HHcy induced the secretion of anti-beta 2 glycoprotein I (anti-β2GPI) antibody from B cells both in vitro and in vivo. Mechanistically, Hcy increased the accumulation of various lipid metabolites in B cells tested by liquid chromatography-tandem mass spectrometry, which contributed to elevated anti-β2GPI IgG secretion. By using the toll-like receptor 4 (TLR4)-specific inhibitor TAK-242 or TLR4-deficient macrophages, we found that culture supernatants from Hcy-activated B cells and HHcy plasma IgG polarized inflammatory macrophages in a TLR4-dependent manner. In addition, HHcy markedly increased the incidence of elastase- and CaPO4-induced AAA in male BALB/c mice, which was prevented in μMT mice. To further determine the importance of IgG in HHcy-aggravated AAA formation, we purified plasma IgG from HHcy or control mice and then transferred the IgG into μMT mice, which were subsequently subjected to elastase- or CaPO4-induced AAA. Compared with μMT mice that received plasma IgG from control mice, μMT mice that received HHcy plasma IgG developed significantly exacerbated elastase- or CaPO4-induced AAA accompanied by increased elastin degradation, MMP2/9 expression, and anti-β2GPI IgG deposition in vascular lesions, as shown by immunofluorescence histochemical staining.. Our findings reveal a novel mechanism by which Hcy-induced B cell-derived pathogenic anti-β2GPI IgG might, at least in part, contribute to HHcy-aggravated chronic vascular inflammation and AAA formation.

Topics: Animals; Aorta, Abdominal; Aortic Aneurysm, Abdominal; Autoantibodies; B-Lymphocytes; beta 2-Glycoprotein I; Calcium Phosphates; Cells, Cultured; Disease Models, Animal; Elastin; Hyperhomocysteinemia; Macrophages; Male; Matrix Metalloproteinase 2; Matrix Metalloproteinase 9; Mice, Inbred BALB C; Mice, Inbred C57BL; Mice, Knockout; Pancreatic Elastase; Toll-Like Receptor 4

Aortic mural inflammatory damage takes a vital part in abdominal aortic aneurysm (AAA). Recently, ulinastatin (UTI) has attracted attention for its anti-inflammatory function. Our study aimed to evaluate potential influences of UTI on experimental AAA.. A mouse model of AAA was induced by infusion of porcine pancreatic elastase (PPE) into the abdominal aorta. Mice were treated with UTI (50,000 U/kg/day i.p.) beginning either immediately or on the 4th day after PPE infusion, with treatment being continued until the 14th day. UTI effects were assessed by aortic diameter measurements and aortic histopathological analysis.. Significant and time-dependent aortic diameter enlargement persisted in the control mice from day 0. In the UTI group, aortic diameter increased, and depletion of aortic mural smooth muscle cells and elastin was significantly -attenuated. Simultaneously, mural CD68+ macrophages, CD8+ T-cell and B220+ B-cell density, as well as neoangiogenesis were suppressed by UTI. In addition, delayed UTI treatment could still effectively limit aneurysm expansion.. UTI treatment limits the formation and growth of experimental AAA, and UTI may be a potential treatment for early AAA disease.

Topics: Animals; Aortic Aneurysm, Abdominal; Disease Models, Animal; Elastin; Glycoproteins; Male; Mice; Mice, Inbred C57BL; Myocytes, Smooth Muscle; Neovascularization, Physiologic; Toll-Like Receptor 4

Williams-Beuren syndrome (WBS) is a rare disorder caused by a heterozygous deletion of 26-28 contiguous genes that affects the brain and cardiovascular system. Here, we investigated whether WBS affects aortic structure and function in the complete deletion (CD) mouse model harbouring the most common deletion found in WBS patients. Thoracic aortas from 3-4 months-old male CD mice and wild-type littermates were mounted in wire myographs or were processed for histomorphometrical analysis. Nitric oxide synthase (NOS) isoforms and oxidative stress levels were assessed. Ascending aortas from young adult CD mice showed moderate (50%) luminal stenosis, whereas endothelial function and oxidative stress were comparable to wild-type. CD mice showed greater contractions to KCl. However, α1-adrenergic contractions to phenylephrine, but not with a thromboxane analogue, were compromised. Decreased phenylephrine responses were not affected by selective inducible NOS blockade with 1400 W, but were prevented by the non-selective NOS inhibitor L-NAME and the selective neuronal NOS inhibitor SMTC. Consistently, CD mice showed increased neuronal NOS expression in aortas. Overall, aortic stenosis in CD mice coexists with excessive nNOS-derived NO signaling that compromises ascending aorta α1-adrenergic contractions. We suggest that increased neuronal NOS signaling may act as a physiological 'brake' against the detrimental effects of stenosis.

Topics: Animals; Aorta, Thoracic; Aortic Stenosis, Supravalvular; Disease Models, Animal; Elastin; Endothelium, Vascular; Ethidium; Male; Mice, Mutant Strains; Nitric Oxide; Nitric Oxide Synthase Type I; Oxidative Stress; Phenylephrine; Receptors, Adrenergic, alpha-1; Williams Syndrome

Sickle cell anemia (SCA) causes chronic inflammation and multiorgan damage. Less understood are the arterial complications, most evident by increased strokes among children. Proteolytic mechanisms, biomechanical consequences, and pharmaceutical inhibitory strategies were studied in a mouse model to provide a platform for mechanistic and intervention studies of large artery damage due to sickle cell disease. Approach and Results: Townes humanized transgenic mouse model of SCA was used to test the hypothesis that elastic lamina and structural damage in carotid arteries increased with age and was accelerated in mice homozygous for SCA (sickle cell anemia homozygous genotype [SS]) due to inflammatory signaling pathways activating proteolytic enzymes. Elastic lamina fragmentation observed by 1 month in SS mice compared with heterozygous littermate controls (sickle cell trait heterozygous genotype [AS]). Positive immunostaining for cathepsin K, a powerful collagenase and elastase, confirmed accelerated proteolytic activity in SS carotids. Larger cross-sectional areas were quantified by magnetic resonance angiography and increased arterial compliance in SS carotids were also measured. Inhibiting JNK (c-jun N-terminal kinase) signaling with SP600125 significantly reduced cathepsin K expression, elastin fragmentation, and carotid artery perimeters in SS mice. By 5 months of age, continued medial thinning and collagen degradation was mitigated by treatment of SS mice with JNK inhibitor.. Arterial remodeling due to SCA is mediated by JNK signaling, cathepsin proteolytic upregulation, and degradation of elastin and collagen. Demonstration in Townes mice establishes their utility for mechanistic studies of arterial vasculopathy, related complications, and therapeutic interventions for large artery damage due to SCA.

Topics: Anemia, Sickle Cell; Animals; Anthracenes; Carotid Arteries; Carotid Artery Diseases; Cathepsin K; Collagen; Disease Models, Animal; Elastin; Hemoglobins; Homozygote; Humans; JNK Mitogen-Activated Protein Kinases; Mice, Transgenic; Mutation; Protein Kinase Inhibitors; Proteolysis; Signal Transduction; Time Factors; Vascular Remodeling

Age-related macular degeneration (AMD) is the leading cause of blindness in Western populations. While an overactive complement system has been linked to pathogenesis, mechanisms contributing to its activation are largely unknown. In aged and AMD eyes, loss of the elastin layer (EL) of Bruch's membrane (BrM) has been reported. Elastin antibodies are elevated in patients with AMD, the pathogenic significance of which is unclear. Here we assess the role of elastin antibodies using a mouse model of smoke-induced ocular pathology (SIOP), which similarly demonstrates EL loss.. C57BL/6J mice were immunized with elastin or elastin peptide oxidatively modified by cigarette smoke (ox-elastin). Mice were then exposed to cigarette smoke or air for 6 months. Visual function was assessed by optokinetic response, retinal morphology by spectral-domain optical coherence tomography and electron microscopy, and complement activation and antibody deposition by Western blot.. Ox-elastin IgG and IgM antibodies were elevated in ox-elastin immunized mice following 6 months of smoke, whereas elastin immunization had a smaller effect. Ox-elastin immunization exacerbated smoke-induced vision loss, with thicker BrM and more damaged retinal pigment epithelium (RPE) mitochondria compared with mice immunized with elastin or nonimmunized controls. These changes were correlated with increased levels of IgM, IgG2, IgG3, and complement activation products in RPE/choroid.. These data demonstrate that SIOP mice generate elastin-specific antibodies and that immunization with ox-elastin exacerbates ocular pathology. Elastin antibodies represented complement fixing isotypes that, together with the increased presence of complement activation seen in immunized mice, suggest that elastin antibodies exert pathogenic effects through mediating complement activation.

Topics: Animals; Autoantibodies; Blotting, Western; Bruch Membrane; Complement Activation; Complement System Proteins; Contrast Sensitivity; Disease Models, Animal; Elastin; Enzyme-Linked Immunosorbent Assay; Geographic Atrophy; Immunization; Immunoglobulin G; Immunoglobulin M; Mice; Mice, Inbred C57BL; Nystagmus, Optokinetic; Oxidation-Reduction; Retinal Pigment Epithelium; Smoking; Tobacco Products; Visual Acuity

Abdominal aortic aneurysms (AAA) is a life-threatening weakening and expansion of the abdominal aorta due to inflammatory cell infiltration and gradual degeneration of extracellular matrix (ECM). There are no pharmacological therapies to treat AAA. We tested the hypothesis that nanoparticle (NP) therapy that targets degraded elastin and delivers anti-inflammatory, anti-oxidative, and ECM stabilizing agent, pentagalloyl glucose (PGG) will reverse advance stage aneurysm in an elastase-induced mouse model of AAA.. Porcine pancreatic elastase (PPE) was applied periadventitially to the infrarenal aorta in mice and AAA was allowed to develop for 14 days. Nanoparticles loaded with PGG (EL-PGG-NPs) were then delivered via IV route at 14-day and 21-day (10 mg/kg of body weight). A control group of mice received no therapy. The targeting of NPs to the AAA site was confirmed with fluorescent dye marked NPs and gold NPs. Animals were sacrificed at 28-d. We found that targeted PGG therapy reversed the AAA by decreasing matrix metalloproteinases MMP-9 and MMP-2, and the infiltration of macrophages in the medial layer. The increase in diameter of the aorta was reversed to healthy controls. Moreover, PGG treatment restored degraded elastic lamina and increased the circumferential strain of aneurysmal aorta to the healthy levels.. Our results support that site-specific delivery of PGG with targeted nanoparticles can be used to treat already developed AAA. Such therapy can reverse inflammatory markers and restore arterial homeostasis.

Topics: Animals; Antibodies; Aorta, Abdominal; Aortic Aneurysm, Abdominal; Disease Models, Animal; Drug Carriers; Elastin; Extracellular Matrix; Gold; Humans; Hydrolyzable Tannins; Immunoconjugates; Injections, Intravenous; Male; Metal Nanoparticles; Mice; Pancreatic Elastase; Serum Albumin, Bovine; Ultrasonography

Tissue engineering represents a promising alternative for reconstructive surgical procedures especially for the repair of bone defects that do not regenerate spontaneously. The present study aimed to evaluate the effects of the elastin matrix (E24/50 and E96/37) incorporated with hydroxyapatite (HA) or morphogenetic protein (BMP) on the bone repair process in the distal metaphysis of rat femur. The groups were: control group (CG), hydrolyzed elastin matrix at 50°C/24h (E24/50), E24/50 + HA (E24/50/HA), E24/50 + BMP (E24/50/BMP), hydrolyzed elastin matrix at 37°C/96h (E96/37), E96/37 + HA (E96/37/HA), E96/37 + BMP (E96/37/BMP). Macroscopic and radiographic analyses showed longitudinal integrity of the femur in all groups without fractures or bone deformities. Microtomographically, all groups demonstrated partial closure by mineralized tissue except for the E96/37/HA group with hyperdense thin bridge formation interconnecting the edges of the ruptured cortical. Histologically, there was no complete cortical recovery in any group, but partial closure with trabecular bone. In defects filled with biomaterials, no chronic inflammatory response or foreign body type was observed. The mean volume of new bone formed was statistically significant higher in the E96/37/HA and E24/50 groups (71.28 ± 4.26 and 66.40 ± 3.69, respectively) than all the others. In the confocal analysis, it was observed that all groups presented new bone markings formed during the experimental period, being less evident in the CG group. Von Kossa staining revealed intense calcium deposits distributed in all groups. Qualitative analysis of collagen fibers under polarized light showed a predominance of red-orange birefringence in the newly regenerated bone with no difference between groups. It was concluded that the E24/50 and E96/37/HA groups promoted, with greater speed, the bone repair process in the distal metaphysis of rat femur.

Topics: Animals; Bone Morphogenetic Proteins; Bone Regeneration; Disease Models, Animal; Durapatite; Elastin; Femur; Humans; Male; Osteogenesis; Rats; Time Factors; Tissue Engineering; Tissue Scaffolds; X-Ray Microtomography

Alstonia scholaris (L.) R. Br. (Apocynaceae) is a medicinal plant in China traditionally used to treat pulmonary diseases, including bronchitis, whooping cough, asthma and chronic obstructive pulmonary disease.. To provide experimental data supporting clinical adaptation of total indole alkaloids ( TA) from A. scholaris leaves for treating emphysema.. An emphysema model was induced by a single intratracheal instillation of porcine pancreatic elastase followed by administration of TA and four main alkaloid components (scholaricine, 19-epischolaricine, vallesamine, and picrinine) for 30 consecutive days. Cytokine levels, histopathological parameters and protein expression in lung tissues were examined.. Administering the TA, picrinine, scholaricine, 19-epischolaricine and vallesamine for 30 days effectively inhibited inflammatory cell accumulation and invasion in the lung tissue and relieved pulmonary tissue injury. Oxygen saturation was enhanced, and interleukin (IL)-1β, monocyte-chemo attractive peptide 1, IL-11, matrix metalloproteinase-12, transforming growth factor-β and vascular endothelial growth factor levels were significantly reduced, likely by suppressing overactivation of alveolar macrophages and pulmonary fibrosis. The elastin content was markedly elevated, and fibronectin was reduced. Bcl-2 expression was significantly increased, and nuclear factor-κB and β-catenin levels were decreased.. TA can be potentially used as an effective novel drug for pulmonary emphysema and exerts its effects through not only inhibiting inflammation of the airway wall and airflow resistance but also promoting lung elastic recoil and protease/anti-protease balance.

Topics: Alstonia; Animals; Anti-Inflammatory Agents; Apoptosis; Cytokines; Disease Models, Animal; Elastin; Fibronectins; Indole Alkaloids; Inflammation Mediators; Lung; Male; Matrix Metalloproteinase 12; Mice, Inbred ICR; Oxygen; Plant Leaves; Pulmonary Emphysema; Signal Transduction; Transforming Growth Factor beta; Vascular Endothelial Growth Factor A

Supravalvular aortic stenosis (SVAS) is a narrowing of the aorta caused by elastin (ELN) haploinsufficiency. SVAS severity varies among patients with Williams-Beuren syndrome (WBS), a rare disorder that removes one copy of ELN and 25-27 other genes. Twenty percent of children with WBS require one or more invasive and often risky procedures to correct the defect while 30% have no appreciable stenosis, despite sharing the same basic genetic lesion. There is no known medical therapy. Consequently, identifying genes that modify SVAS offers the potential for novel modifier-based therapeutics. To improve statistical power in our rare-disease cohort (N = 104 exomes), we utilized extreme-phenotype cohorting, functional variant filtration and pathway-based analysis. Gene set enrichment analysis of exome-wide association data identified increased adaptive immune system variant burden among genes associated with SVAS severity. Additional enrichment, using only potentially pathogenic variants known to differ in frequency between the extreme phenotype subsets, identified significant association of SVAS severity with not only immune pathway genes, but also genes involved with the extracellular matrix, G protein-coupled receptor signaling and lipid metabolism using both SKAT-O and RQTest. Complementary studies in Eln+/-; Rag1-/- mice, which lack a functional adaptive immune system, showed improvement in cardiovascular features of ELN insufficiency. Similarly, studies in mixed background Eln+/- mice confirmed that variations in genes that increase elastic fiber deposition also had positive impact on aortic caliber. By using tools to improve statistical power in combination with orthogonal analyses in mice, we detected four main pathways that contribute to SVAS risk.

Topics: Adolescent; Animals; Aortic Stenosis, Supravalvular; Child, Preschool; Constriction, Pathologic; Disease Models, Animal; Elastin; Exome Sequencing; Haploinsufficiency; Homeodomain Proteins; Humans; Male; Mice; Risk Factors; Williams Syndrome

Using maximum diameter of an abdominal aortic aneurysm (AAA) alone for management can lead to delayed interventions or unnecessary urgent repairs. Abdominal aortic aneurysm stiffness plays an important role in its expansion and rupture. In vivo aortic magnetic resonance elastography (MRE) was developed to spatially measure AAA stiffness in previous pilot studies and has not been thoroughly validated and evaluated for its potential clinical value. This study aims to evaluate noninvasive in vivo aortic MRE-derived stiffness in an AAA porcine model and investigate the relationships between MRE-derived AAA stiffness and (1) histopathology, (2) uniaxial tensile test, and (3) burst testing for assessing MRE's potential in evaluating AAA rupture risk.. Abdominal aortic aneurysm was induced in 31 Yorkshire pigs (n = 226 stiffness measurements). Animals were randomly divided into 3 cohorts: 2-week, 4-week, and 4-week-burst. Aortic MRE was sequentially performed. Histopathologic analyses were performed to quantify elastin, collagen, and mineral densities. Uniaxial tensile test and burst testing were conducted to measure peak stress and burst pressure for assessing the ultimate wall strength.. Magnetic resonance elastography-derived AAA stiffness was significantly higher than the normal aorta. Significant reduction in elastin and collagen densities as well as increased mineralization was observed in AAAs. Uniaxial tensile test and burst testing revealed reduced ultimate wall strength. Magnetic resonance elastography-derived aortic stiffness correlated to elastin density (ρ = -0.68; P < 0.0001; n = 60) and mineralization (ρ = 0.59; P < 0.0001; n = 60). Inverse correlations were observed between aortic stiffness and peak stress (ρ = -0.32; P = 0.0495; n = 38) as well as burst pressure (ρ = -0.55; P = 0.0116; n = 20).. Noninvasive in vivo aortic MRE successfully detected aortic wall stiffening, confirming the extracellular matrix remodeling observed in the histopathologic analyses. These mural changes diminished wall strength. Inverse correlation between MRE-derived aortic stiffness and aortic wall strength suggests that MRE-derived stiffness can be a potential biomarker for clinically assessing AAA wall status and rupture potential.

Topics: Animals; Aortic Aneurysm, Abdominal; Collagen; Disease Models, Animal; Elasticity Imaging Techniques; Elastin; Swine; Vascular Calcification; Vascular Stiffness

Pelvic organ prolapse (POP) decreases quality of life for many women, but its pathophysiology is poorly understood. We have previously shown that Lysyl oxidase-like 1 knockout (Loxl1 KO) mice reliably prolapse with age and increased parity, similar to women. Both this model and clinical studies also indicate that altered elastin metabolism in pelvic floor tissues plays a role in POP manifestation, although it is unknown if this is a cause or effect. Using Loxl1 KO mice, we investigated the effects of genetic absence of Loxl1, vaginal parity, and presence of POP on the expression of genes and proteins key to the production and regulation of elastic matrix. Cultured cells isolated from vaginal explants of mice were assayed with Fastin for elastic matrix, as well as RT-PCR and Western blot for expression of genes and proteins important for elastin homeostasis. Elastin synthesis significantly decreased with absence of LOXL1 and increased with parity (p < .001), but not with POP. Cells from prolapsed mice expressed significantly decreased MMP-2 (p < .05) and increased TIMP-4 (p < .05). The results suggest changes to elastin structure rather than amounts in prolapsed mice as well as poor postpartum elastin turnover, resulting in accumulation of damaged elastic fibers leading to abnormal tropoelastin deposition. POP may thus, be the result of an inability to initiate the molecular mechanisms necessary to clear and replace damaged elastic matrix in pelvic floor tissues after vaginal birth.

Topics: Amino Acid Oxidoreductases; Animals; Cells, Cultured; Disease Models, Animal; Elastin; Female; Homeostasis; Mice, Inbred C57BL; Mice, Knockout; Pelvic Organ Prolapse; Vagina

Pulmonary arterial hypertension-congenital heart disease (PAH-CHD) is characterized by systemic to pulmonary arterial shunts and sensitively responds to volume overload and stretch of the vascular wall leading to pulmonary vascular remodeling. We hypothesized that the responses of pulmonary artery smooth muscle cells (PASMCs) to mechanical stress-associated volume overload may promote vascular remodeling in PAH-CHD. Here, we show that significantly increased collagen was in the PA adventitial layer by trichrome staining in PAH-CHD patients and an aortocaval fistula (ACF) rat model in which chronic vascular volume overload induced-PAH. We assessed the gene expression profiles of SMC markers, extracellular matrix, and collagen in isolated SMCs from pulmonary and thoracic vessels with cyclic stretch-triggered responses by real-time PCR analysis. The data corresponded to collagen deposition, which modulated pulmonary vascular remodeling in clinical and experimental PAH-ACF cases as well as in cyclic stretch-triggered SMCs in an in vitro model. We observe that collagen I A2 (COLIA2) is expressed in the control rat, but collagen I A1 (COLIA1) and Notchs remarkably increase in the lungs of ACF rats. Interestingly, closing the left-to-right shunt that leads to a reduced blood volume in the PA system of ACF rats (ACFRs) decreased the expression of COLIA1 and increased that of collagen I A2(COLIA2). This study contributes to the stretch-induced responses of SMCs and provides important future directions for therapies aimed at preventing abnormal matrix protein synthesis in volume overload-induced pulmonary hypertension (PH).

Topics: Animals; Collagen; Disease Models, Animal; Elastin; Humans; Hypertrophy, Right Ventricular; Muscle, Smooth, Vascular; Myocytes, Smooth Muscle; Pulmonary Arterial Hypertension; Pulmonary Artery; Pulmonary Circulation; Rats; Receptors, Notch; Stress, Mechanical; Vascular Remodeling; Vascular Stiffness

Achilles tendon injuries are a frequent problem in orthopaedic surgery due to their limited healing capacity and the controversy surrounding surgical treatment. In recent years, tissue engineering research has focused on the development of biomaterials to improve this healing process. The aim of this study was to analyze the effect of tendon augmentation with a nanostructured fibrin-agarose hydrogel (NFAH) or genipin cross-linked nanostructured fibrin-agarose hydrogel (GP-NFAH), on the healing process of the Achilles tendon in rats.. NFAH, GP-NFAH, and MatriDerm (control) scaffolds were generated (five in each group). A biomechanical and cell-biomaterial-interaction characterization of these biomaterials was then performed: Live/Dead Cell Viability Assay, water-soluble tetrazolium salt-1 (WST-1) assay, and DNA-released after 48 hours. Additionally, a complete section of the left Achilles tendon was made in 24 Wistar rats. Animals were separated into four treatment groups (six in each group): direct repair (Control), tendon repair with MatriDerm, or NFAH, or GP-NFAH. Animals were euthanized for further histological analyses after four or eight weeks post-surgery. The Achilles tendons were harvested and a histopathological analysis was performed.. Tensile test revealed that NFAH and GP-NFAH had significantly higher overall biomechanical properties compared with MatriDerm. Moreover, biological studies confirmed a high cell viability in all biomaterials, especially in NFAH. In addition, in vivo evaluation of repaired tendons using biomaterials (NFAH, GP-NFAH, and MatriDerm) resulted in better organization of the collagen fibres and cell alignment without clinical complications than direct repair, with a better histological score in GP-NFAH.. In this animal model we demonstrated that NFAH and GP-NFAH had the potential to improve tendon healing following a surgical repair. However, future studies are needed to determine the clinical usefulness of these engineered strategies. Cite this article:

Topics: Achilles Tendon; Animals; Biocompatible Materials; Cellular Microenvironment; Collagen; Disease Models, Animal; Elastin; Fibrin; Hydrogels; Male; Nanostructures; Random Allocation; Rats; Rats, Wistar; Regeneration; Tendon Injuries; Tendons; Tissue Engineering; Wound Healing

Thoracic aortic dissection (TAD) is associated with matrix changes, biochemical changes, and inflammatory markers like interleukin-1 beta (IL-1β). However, the exact mechanism remains unknown. This study aimed to investigate the role of IL-1β, matrix metalloproteinase (MMP)-2, MMP-9, smooth muscle cell apoptosis, and elastic fibre fracture in the development of TAD in a rat model.. The TAD rat model was induced by β-aminopropionitrile (BAPN). TAD was investigated in 112 male Sprague-Dawley rats, which were equally divided into four groups of 28 rats (Control, BAPN, BAPN + IL-1β, and BAPN + IL-1β antibody). Systolic blood pressure, survival, and the development of TAD were measured after six weeks. Expression of IL-1β, MMP-2, and MMP-9 was measured by Western blot. Apoptosis, aortic elastin concentration, and biomechanical characteristics were measured by the TdT mediated dUTP nick end labelling assay, Victoria blue staining, and in vitro testing.. During six weeks, the mortality was 0% (0/28) in the control group, 53.6% (15/28) in the BAPN group (p < .001 compared with the control group), 75.0% (21/28) in the BAPN + IL-1β group (p = .007 compared with the BAPN group), and 35.7% (10/28) in the BAPN + IL-1β antibody group (p = .023 compared with BAPN group and p < .001 compared with the BAPN + IL-1β group). IL-1β treatment deteriorates BAPN induced mortality and aneurysm expansion, which were attenuated by anti-IL-1β treatment. In BAPN + IL-1β group, stress and strain parameters were decreased by 13.5%-53.5% and elastin content was decreased by 14%, and IL-1β, MMP-2, and MMP-9 were expressed higher by 117%, 108%, and 75% when compared with the rats in the BAPN group. Contrarily, in the BAPN + IL-1β antibody group, the above changes could be completely (strain, elastin content, and expression of MMP-2) or partly (elasticity modulus, stress, and expression of MMP-9) blocked by anti-IL-1β treatment.. IL-1β plays a critical role in TAD formation by altering the expression of MMP-2 and MMP-9, degrading the aortic wall matrix, causing elastic fibre rupture, and changing the stress or strain of the aortic wall. Anti-IL-1β reduces the later effects and could be one of the molecular targets for prognosis and drug treatment of TAD in the future.

Topics: Aminopropionitrile; Animals; Antibodies; Aorta, Thoracic; Aortic Aneurysm, Thoracic; Aortic Dissection; Apoptosis; Disease Models, Animal; Elastin; Interleukin-1beta; Male; Matrix Metalloproteinase 2; Matrix Metalloproteinase 9; Rats; Rats, Sprague-Dawley; Survival Rate

Chronic renovascular disease (RVD) can lead to a progressive loss of renal function, and current treatments are inefficient. We designed a fusion of vascular endothelial growth factor (VEGF) conjugated to an elastin-like polypeptide (ELP) carrier protein with an N-terminal kidney-targeting peptide (KTP). We tested the hypothesis that KTP-ELP-VEGF therapy will effectively recover renal function with an improved targeting profile. Further, we aimed to elucidate potential mechanisms driving renal recovery.. Unilateral RVD was induced in 14 pigs. Six weeks later, renal blood flow (RBF) and glomerular filtration rate (GFR) were quantified by multidetector CT imaging. Pigs then received a single intrarenal injection of KTP-ELP-VEGF or vehicle. CT quantification of renal hemodynamics was repeated 4 weeks later, and then pigs were euthanized. Ex vivo renal microvascular (MV) density and media-to-lumen ratio, macrophage infiltration, and fibrosis were quantified. In parallel, THP-1 human monocytes were differentiated into naïve macrophages (M0) or inflammatory macrophages (M1) and incubated with VEGF, KTP-ELP, KTP-ELP-VEGF, or control media. The mRNA expression of macrophage polarization and angiogenic markers was quantified (qPCR).. Intrarenal KTP-ELP-VEGF improved RBF, GFR, and MV density and attenuated MV media-to-lumen ratio and renal fibrosis compared to placebo, accompanied by augmented renal M2 macrophages. In vitro, exposure to VEGF/KTP-ELP-VEGF shifted M0 macrophages to a proangiogenic M2 phenotype while M1s were nonresponsive to VEGF treatment.. Our results support the efficacy of a new renal-specific biologic construct in recovering renal function and suggest that VEGF may directly influence macrophage phenotype as a possible mechanism to improve MV integrity and function in the stenotic kidney.

Topics: Animals; Atherosclerosis; Disease Models, Animal; Elastin; Female; Glomerular Filtration Rate; Humans; Kidney; Male; Microvessels; Peptides; Recombinant Fusion Proteins; Recovery of Function; Renal Artery Obstruction; Renal Circulation; Sus scrofa; Vascular Endothelial Growth Factor A

Chronic intermittent hypoxia (CIH) is a major determinant of the cardiovascular morbidity associated with obstructive sleep apnoea (OSA), and the magnitude of CIH impact may be influenced by ageing. Here, we assessed the role of ageing in the early cardiovascular structural remodelling induced by severe CIH in a murine model of OSA.. Early vascular remodelling was observed in young mice exposed to CIH as illustrated by intima-media thickening (mean change: 4.6 ± 2.6 μm; P = 0.02), elastin fibre disorganization (mean change: 9.2 ± 4.5%; P = 0.02) and fragmentation (mean change: 2.5 ± 0.8%; P = 0.03), and collagen (mean change: 3.2 ± 0.6%; P = 0.001) and mucopolysaccharide accumulation (mean change: 2.4 ± 0.8%; P = 0.01). In contrast, vascular remodelling was not apparent in aged mice exposed to CIH. Furthermore, left ventricular perivascular fibrosis (mean change: 0.71 ± 0.1; P < 0.001) and hypertrophy (mean change: 0.17 ± 0.1; P = 0.038) were increased by CIH exposure in young mice, but not in aged mice. Principal component analysis identified similar cardiovascular alterations among the young mice exposed to CIH and both older mouse groups, suggesting that CIH induces premature cardiovascular senescence.. Cardiovascular remodelling induced by severe CIH is affected by the age at which CIH onset occurs, suggesting that the deleterious cardiovascular effects associated with CIH may be more pronounced in younger populations, and such changes resemble chronological age-related declines in cardiovascular structural integrity.

Topics: Age Factors; Aging; Animals; Chronic Disease; Collagen; Disease Models, Animal; Elastin; Female; Glycosaminoglycans; Hypoxia; Mice; Mice, Inbred C57BL; Sleep Apnea, Obstructive; Tunica Intima; Vascular Remodeling

Chronic kidney disease (CKD) universally associates with renal microvascular rarefaction and inflammation, but whether a link exists between these 2 processes is unclear. We designed a therapeutic construct of VEGF (vascular endothelial growth factor) fused to an ELP (elastin-like polypeptide) carrier and show that it improves renal function in experimental renovascular disease. We test the hypothesis that ELP-VEGF therapy will improve CKD, and that recovery will be driven by decreasing microvascular rarefaction partly via modulation of macrophage phenotype and inflammation. CKD was induced in 14 pigs, which were observed for 14 weeks. At 6 weeks, renal blood flow and filtration were quantified using multidetector computed tomography, and then pigs received single intrarenal ELP-VEGF or placebo (n=7 each). Renal function was quantified again 4 and 8 weeks later. Pigs were euthanized and renal microvascular density, angiogenic and inflammatory markers, fibrosis, macrophage infiltration, and phenotype were quantified. Loss of renal hemodynamics in CKD was progressively recovered by ELP-VEGF therapy, accompanied by improved renal microvascular density, fibrosis, and expression of inflammatory mediators. Although renal macrophage infiltration was similar in both CKD groups, ELP-VEGF therapy distinctly shifted their phenotype from proinflammatory M1 to VEGF-expressing M2. Our study unravels potential mechanisms and feasibility of a new strategy to offset progression of CKD using drug-delivery technologies. The results indicate that renal recovery after ELP-VEGF therapy was largely driven by modulation of renal macrophages toward VEGF-expressing M2 phenotype, restoring VEGF signaling and sustaining improvement of renal function and microvascular integrity in CKD.

Topics: Animals; Biopsy, Needle; Cells, Cultured; Disease Models, Animal; Drug Carriers; Elastin; Immunohistochemistry; Injections, Intralesional; Kidney Function Tests; Macrophages; Microcirculation; Multidetector Computed Tomography; Random Allocation; Recovery of Function; Renal Circulation; Renal Insufficiency, Chronic; Sensitivity and Specificity; Sus scrofa; Tissue and Organ Harvesting; Treatment Outcome; Vascular Endothelial Growth Factor A

Molecular MRI is a promising in-vivo modality to detect and quantify morphological and molecular vessel-wall changes in atherosclerosis. The combination of different molecular biomarkers may improve the risk stratification of patients. This study aimed to investigate the feasibility of simultaneous visualization and quantification of plaque-burden and inflammatory activity by dual-probe molecular MRI in a mouse-model of progressive atherosclerosis and in response-to-therapy. Homozygous apolipoprotein E knockout mice (ApoE

Topics: Animals; Contrast Media; Diet, High-Fat; Disease Models, Animal; Elastin; Feasibility Studies; Ferrosoferric Oxide; Gadolinium; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Magnetic Resonance Imaging; Male; Mice; Mice, Knockout, ApoE; Nitric Oxide; Plaque, Atherosclerotic; Pravastatin; Sensitivity and Specificity

Animal models are useful for investigating the genesis of pelvic floor dysfunction and for developing novel therapies for its treatment. There is a need for an alternative large-animal model to the nonhuman primate. Therefore we studied the effects of the first vaginal delivery, ovariectomy and systemic hormonal replacement therapy (HRT) on the biomechanical and structural properties of the ovine vagina.. We examined the gross anatomical properties of nulliparous, primiparous, ovariectomized multiparous, and ovariectomized hormone-replaced multiparous sheep (six animals per group). We also harvested mid-vaginal and distal vaginal tissue to determine smooth muscle contractility and passive biomechanical properties, for morphometric assessment of the vaginal wall layers, to determine collagen and elastin content, and for immunostaining for α-smooth muscle actin and estrogen receptor-α.. There were no regional differences in the nulliparous vagina. One year after the first vaginal delivery, stiffness and contractility of the distal vagina were decreased, whereas the elastin content increased. The mid-vagina of ovariectomized sheep was stiff, and its epithelium was thin and lacked glycogen. HRT decreased the stiffness of the mid-vagina by 45% but had no measurable effect on contractility or elastin content, and increased epithelial thickness and glycogen content. HRT also increased the epithelial thickness and glycogen content of the distal vagina. At this location, there were no changes in morphology or stiffness.. In sheep, life events including delivery and ovariectomy affect the biomechanical properties of the vagina in a region-specific way. Vaginal delivery mainly affects the distal region by decreasing stiffness and contractility. HRT can reverse the increase in stiffness of the mid-vagina observed after surgical induction of menopause. These observations are in line with scanty biomechanical measurements in comparable clinical specimens.

Topics: Actins; Animals; Biomechanical Phenomena; Collagen; Disease Models, Animal; Elastin; Epithelium; Estrogen Receptor alpha; Female; Glycogen; Hormone Replacement Therapy; Muscle Contraction; Muscle, Smooth; Ovariectomy; Parity; Parturition; Pelvic Floor Disorders; Sheep; Vagina

Deterioration of lung functions and degradation of elastin fibers with age are accelerated during chronic obstructive pulmonary disease (COPD). Excessive genesis of soluble elastin peptides (EP) is a key factor in the pathophysiology of COPD. We have previously demonstrated that 6-wk-old mice exhibited emphysematous structural changes associated with proinflammatory immune response after EP instillation. In this study, we investigated the consequences of aging on inflammatory, immune, and histological criteria associated with murine emphysema progression after EP exposure. Young (6 wk old) and elderly (15 mo old) C57BL/6J mice were endotracheally instilled with EP, and, at various time points after treatment, the inflammatory cell profiles from bronchoalveolar lavage fluids (BALF) and the T-lymphocyte phenotypes, at local and systemic levels, were analyzed by flow cytometry. Lungs were also prepared to allow morphological and histological analysis by confocal microscopy. Elderly mice exhibited an earlier development of pulmonary emphysema, characterized by an increase of the inflammatory and lymphocytic infiltrates, extracellular matrix breakdown, and airspace enlargement compared with young mice. This age-dependent parenchymal tissue remodeling was associated with an increase of the matrix metalloproteinase expressions and desmosine levels in BALF and/or sera of EP-treated mice. In addition, both the proportion of CD4

Topics: Aging; Animals; Bronchoalveolar Lavage Fluid; CD4-Positive T-Lymphocytes; CD8-Positive T-Lymphocytes; Desmosine; Disease Models, Animal; Elastin; Female; Inflammation; Lung; Macrophages, Alveolar; Matrix Metalloproteinases; Mice; Mice, Inbred C57BL; Neutrophils; Proteolysis; Pulmonary Emphysema

Molecular magnetic resonance imaging is a promising modality for the characterization of abdominal aortic aneurysms (AAAs). The combination of different molecular imaging biomarkers may improve the assessment of the risk of rupture. This study investigates the feasibility of imaging inflammatory activity and extracellular matrix degradation by concurrent dual-probe molecular magnetic resonance imaging in an AAA mouse model.. Osmotic minipumps with a continuous infusion of Ang II (angiotensin II; 1000 ng/[kg·min]) to induce AAAs were implanted in apolipoprotein-deficient mice (N=58). Animals were assigned to 2 groups. In group 1 (longitudinal group, n=13), imaging was performed once after 1 week with a clinical dose of a macrophage-specific iron oxide-based probe (ferumoxytol, 4 mgFe/kg, surrogate marker for inflammatory activity) and an elastin-specific gadolinium-based probe (0.2 mmol/kg, surrogate marker for extracellular matrix degradation). Animals were then monitored with death as end point. In group 2 (week-by-week-group), imaging with both probes was performed after 1, 2, 3, and 4 weeks (n=9 per group). Both probes were evaluated in 1 magnetic resonance session.. The combined assessment of inflammatory activity and extracellular matrix degradation was the strongest predictor of AAA rupture (sensitivity 100%; specificity 89%; area under the curve, 0.99). Information from each single probe alone resulted in lower predictive accuracy. In vivo measurements for the elastin- and iron oxide-probe were in good agreement with ex vivo histopathology (Prussian blue-stain: R. This study demonstrates the potential of the concurrent assessment of inflammatory activity and extracellular matrix degradation by dual-probe molecular magnetic resonance imaging in an AAA mouse model. Based on the combined information from both molecular probes, the rupture of AAAs could reliably be predicted.

Topics: Angiotensin II; Animals; Aorta, Abdominal; Aortic Aneurysm, Abdominal; Aortic Rupture; Contrast Media; Disease Models, Animal; Disease Progression; Elastin; Extracellular Matrix; Feasibility Studies; Ferrosoferric Oxide; Gadolinium DTPA; Inflammation Mediators; Magnetic Resonance Imaging; Male; Mice, Knockout, ApoE; Molecular Imaging; Predictive Value of Tests; Reproducibility of Results; Time Factors

The USFDA-approved immunosuppressive drug rapamycin (Rapa), despite its potency, is limited by poor bioavailability and a narrow therapeutic index. In this study, we sought to improve bioavailability of Rapa with subcutaneous (SC) administration and to test its therapeutic feasibility and practicality in a murine model of Sjögren's syndrome (SS), a systemic autoimmune disease with no approved therapies. To improve its therapeutic index, we formulated Rapa with a carrier termed FAF, a fusion of the human cytosolic FK506-binding protein 12 (FKBP12) and an elastin-like polypeptide (ELP). The resulting 97 kDa FAF (i) has minimal burst release, (ii) is "humanized", (iii) is biodegradable, (iv) solubilizes two Rapa per FAF, and (v) avoids organic solvents or amphiphilic carriers. Demonstrating high stability, FAF remained soluble and monodisperse with a hydrodynamic radius of 8 nm at physiological temperature. A complete pharmacokinetic (PK) analysis of FAF revealed that the bioavailability of SC FAF was 60%, with significantly higher blood concentration during the elimination phase compared to IV FAF. The plasma concentration of Rapa delivered by FAF was 8-fold higher with a significantly increased plasma-to-whole blood ratio relative to free Rapa, 24 h after injection. To evaluate therapeutic effects, FAF-Rapa was administered SC every other day for 2 weeks to male non-obese diabetic (NOD) mice, which develop an SS-like autoimmune-mediated lacrimal gland (LG) inflammation and other characteristic features of SS. Both FAF-Rapa and free Rapa exhibited immunomodulatory effects by significantly suppressing lymphocytic infiltration, gene expression of IFN-γ, MHC II, type I collagen and IL-12a, and cathepsin S (CTSS) activity in LG compared to controls. Serum chemistry and histopathological analyses in major organs revealed no apparent toxicity of FAF-Rapa. Given its improved PK and equipotent therapeutic efficacy compared to free Rapa, FAF-Rapa is of further interest for systemic treatments for autoimmune diseases like SS.

Topics: Animals; Cathepsins; Disease Models, Animal; Drug Carriers; Drug Compounding; Drug Liberation; Drug Stability; Elastin; Immunosuppressive Agents; Injections, Subcutaneous; Male; Mice; Mice, Inbred NOD; Peptides; Sirolimus; Sjogren's Syndrome; Tacrolimus Binding Protein 1A

Zebrafish (Danio rerio) is widely used as an animal model to understand the pathophysiology of cardiovascular diseases. Here, we present the adult cardiac phenotype of weak atrium, myh6

Topics: Animals; Disease Models, Animal; Elastin; Heart Atria; Hyperplasia; Hypertrophy, Left Ventricular; Hypertrophy, Right Ventricular; Mutation; Myocytes, Cardiac; Myosin Heavy Chains; Zebrafish; Zebrafish Proteins

Loss of immune tolerance to self-antigens can promote chronic inflammation and disrupt the normal function of multiple organs, including the lungs. Degradation of elastin, a highly insoluble protein and a significant component of the lung structural matrix, generates proinflammatory molecules. Elastin fragments (EFs) have been detected in the serum of smokers with emphysema, and elastin-specific T cells have also been detected in the peripheral blood of smokers with emphysema. However, an animal model that could recapitulate T cell-specific autoimmune responses by initiating and sustaining inflammation in the lungs is lacking. In this study, we report an animal model of autoimmune emphysema mediated by the loss of tolerance to elastin. Mice immunized with a combination of human EFs plus rat EFs but not mouse EFs showed increased infiltration of innate and adaptive immune cells to the lungs and developed emphysema. We cloned and expanded mouse elastin-specific CD4

Topics: Adaptive Immunity; Animals; Autoimmunity; Cell Line; Disease Models, Animal; Elastin; Female; HEK293 Cells; Humans; Immune Tolerance; Immunity, Innate; Inflammation; Lung; Mice; Mice, Inbred C57BL; Pulmonary Disease, Chronic Obstructive; Pulmonary Emphysema; Smoking

Interstitial cystitis (IC), also known as painful bladder syndrome, is a debilitating chronic condition with many patients failing to respond to current treatment options. Rapid clearance, mucosal coating, and tight epithelium create strong natural barriers that reduce the effectiveness of many pharmacological interventions in the bladder. Intravesical drug delivery (IDD) is the administration of therapeutic compounds or devices to the urinary bladder via a urethral catheter. Previous work in improving IDD for IC has focused on the sustained delivery of analgesics within the bladder and other small molecule drugs which do not address underlying inflammation and bladder damage. Therapeutic glycosaminoglycans (GAG) function by restoring the mucosal barrier within the bladder, promoting healing responses, and preventing irritating solutes from reaching the bladder wall. There is an unmet medical need for a therapy that provides both acute relief of symptoms while alleviating underlying physiological sources of inflammation and promoting healing within the urothelium. Semi-synthetic glycosaminoglycan ethers (SAGE) are an emerging class of therapeutic GAG with intrinsic anti-inflammatory and analgesic properties. To reduce SAGE clearance and enhance its accumulation in the bladder, we developed a silk-elastinlike protein polymer (SELP) based system to enhance SAGE IDD. We evaluated in vitro release kinetics, rheological properties, impact on bladder function, pain response, and bladder inflammation and compared their effectiveness to other temperature-responsive polymers including Poloxamer 407 and poly(lactic-co-glycolic acid)-poly(ethylene glycol). SAGE delivered via SELP-enhanced intravesical delivery substantially improved SAGE accumulation in the urothelium, provided a sustained analgesic effect 24 h after administration, and reduced inflammation.

Topics: Animals; Anti-Inflammatory Agents; Antimicrobial Cationic Peptides; Behavior, Animal; Cathelicidins; Cystitis, Interstitial; Delayed-Action Preparations; Disease Models, Animal; Drug Delivery Systems; Drug Liberation; Elastin; Female; Gels; Glycosaminoglycans; Mice, Inbred C57BL; Polymers; Silk; Temperature; Urothelium

Synthetic non-absorbable meshes are widely used to augment surgical repair of pelvic organ prolapse (POP) and stress urinary incontinence (SUI), but these meshes are associated with serious complications. This study compares the attachment and extracellular matrix (ECM) production of adipose-derived stem cells (ADSCs) on different biodegradable nanomaterials to develop tissue engineered repair materials.. Rat ADSCs were isolated and cultured on electrospun poly-L-lactic acid (PLA) and electrospun poly(L-lactide)-trimethylene carbonate-gycolide (PLTG) terpolymers for 1 and 2 weeks. Samples were tested for cell proliferation (cell counting kit-8), microstructure, and morphology (scanning electron microscopy), production of ECM components (immunostaining for collagen I, collagen III, and elastin) and biomechanical properties (uniaxial tensile methods).. The ADSCs showed good attachment and proliferation on both PLA and PLTG scaffolds. The production of collagen I and collagen III on both scaffolds was greater at 14 days than at 7 days and was greater on PLTG scaffolds than on PLA scaffolds, but these differences were not significant. The addition of ADSCs onto scaffolds led to a significant increase in the biomechanical properties of both PLA and PLTG scaffolds compared with unseeded scaffolds.. These data support the use of both PLA and PLTG as tissue-engineered repair materials for POP or SUI.

Topics: Adipose Tissue; Animals; Cell Proliferation; Collagen Type I; Collagen Type II; Disease Models, Animal; Elastin; Female; Humans; Pelvic Organ Prolapse; Rats; Rats, Sprague-Dawley; Stem Cells; Tissue Engineering; Tissue Scaffolds; Triglycerides; Urinary Incontinence

Glutaminolysis is the metabolic process of glutamine, aberration of which has been implicated in several pathogeneses. Although we and others recently found a diversity of metabolic dysregulation in organ fibrosis, it is unknown if glutaminolysis regulates the profibrotic activities of myofibroblasts, the primary effector in this pathology. In this study, we found that lung myofibroblasts demonstrated significantly augmented glutaminolysis that was mediated by elevated glutaminase 1 (Gls1). Inhibition of glutaminolysis by specific Gls1 inhibitors CB-839 and BPTES as well as Gls1 siRNA blunted the expression of collagens but not that of fibronectin, elastin, or myofibroblastic marker smooth muscle actin-α. We found that glutaminolysis enhanced collagen translation and stability, which were mediated by glutaminolysis-dependent mTOR complex 1 activation and collagen proline hydroxylation, respectively. Furthermore, we found that the amount of the glutaminolytic end product α-ketoglutarate (α-KG) was increased in myofibroblasts. Similar to glutaminolysis, α-KG activated mTOR complex 1 and promoted the expression of collagens but not of fibronectin, elastin, or smooth muscle actin-α. α-KG also remarkably inhibited collagen degradation in fibroblasts. Taken together, our studies identified a previously unrecognized mechanism by which a major metabolic program regulates the exuberant production of collagens in myofibroblasts and suggest that glutaminolysis is a novel therapeutic target for treating organ fibrosis, including idiopathic pulmonary fibrosis.

Topics: Actins; Animals; Benzeneacetamides; Cells, Cultured; Collagen; Disease Models, Animal; Elastin; Enzyme Activation; Fibronectins; Glutaminase; Glutamine; Humans; Hydroxylation; Ketoglutaric Acids; Mice; Mice, Inbred C57BL; Myofibroblasts; Proline; Pulmonary Fibrosis; RNA Interference; RNA, Small Interfering; Sulfides; Thiadiazoles; TOR Serine-Threonine Kinases

Topics: Angiotensin II; Animals; Aorta, Abdominal; Aortic Aneurysm, Abdominal; Apoptosis; Cell Line; Disease Models, Animal; Elastin; Male; MAP Kinase Signaling System; Matrix Metalloproteinase 2; Matrix Metalloproteinase 9; Mice; Mice, Knockout, ApoE; Myocytes, Smooth Muscle; Neuropeptides; Proteolysis; Reactive Oxygen Species

A critical event in the adaptation to extrauterine life is relaxation of the pulmonary vasculature at birth, allowing for a rapid increase in pulmonary blood flow that is essential for efficient gas exchange. Failure of this transition leads to pulmonary hypertension (PH), a major cause of newborn mortality associated with preterm birth, infection, hypoxia, and malformations including congenital diaphragmatic hernia (CDH). While individual vasoconstrictor and dilator genes have been identified, the coordination of their expression is not well understood. Here, we found that lung mesenchyme-specific deletion of CDH-implicated genes encoding pre-B cell leukemia transcription factors (Pbx) led to lethal PH in mice shortly after birth. Loss of Pbx genes resulted in the misexpression of both vasoconstrictors and vasodilators in multiple pathways that converge to increase phosphorylation of myosin in vascular smooth muscle (VSM) cells, causing persistent constriction. While targeting endothelin and angiotensin, which are upstream regulators that promote VSM contraction, was not effective, treatment with the Rho-kinase inhibitor Y-27632 reduced vessel constriction and PH in Pbx-mutant mice. These results demonstrate a lung-intrinsic, herniation-independent cause of PH in CDH. More broadly, our findings indicate that neonatal PH can result from perturbation of multiple pathways and suggest that targeting the downstream common effectors may be a more effective treatment for neonatal PH.

Topics: Alleles; Animals; Apoptosis; Cell Proliferation; Disease Models, Animal; Echocardiography; Elastin; Female; Gene Deletion; Hernias, Diaphragmatic, Congenital; Homeodomain Proteins; Hypertension, Pulmonary; Lung; Mice; Mice, Knockout; Muscle, Smooth, Vascular; Myocytes, Smooth Muscle; Myosins; Parturition; Phosphorylation; Pre-B-Cell Leukemia Transcription Factor 1; Proto-Oncogene Proteins; Pulmonary Artery; Respiration; Vasoconstriction

Insights into the clinical course of COPD indicate the need for new therapies for this condition. The discovery of alpha-1 antitrypsin deficiency (AATD) led to the protease-antiprotease imbalance hypothesis, which was applied to COPD related to AATD as well as COPD not related to AATD. The discovery of AATD brought recognition to the importance of elastin fibers in maintaining lung matrix structure. Two cross-linking amino acids, desmosine and isodesmosine (DI), are unique to mature elastin and can serve as biomarkers of the degradation of elastin. The intravenous augmentation treatment and lung density in severe alpha-1 antitrypsin deficiency (RAPID) study shows a correlation of an anatomic index of COPD (on CT imaging) correlating with a chemical indicator of matrix injury in COPD, DI. The results suggest that preservation of lung elastin structure may slow the progression of COPD. Hyaluronan aerosol decreases the severity of elastase-induced emphysema in animals and has induced reductions in DI levels in preliminary human studies. Hyaluronan deserves further development as a therapy for COPD.

Topics: Adjuvants, Immunologic; Animals; Biomarkers; Clinical Trials as Topic; Desmosine; Disease Models, Animal; Elastin; Glycosaminoglycans; Humans; Hyaluronic Acid; Immunity, Cellular; Isodesmosine; Pulmonary Disease, Chronic Obstructive; Pulmonary Emphysema; Rats

Abdominal aortic aneurysm (AAA) has high mortality rate when ruptured, but currently, there is no proven pharmacological therapy for AAA because of our poor understanding of its pathogenesis. The current study explored a novel role of smooth muscle cell (SMC) BMAL1 (brain and muscle Arnt-like protein-1)-a transcription factor known to regulate circadian rhythm-in AAA development.. SMC-selective deletion of BMAL1 potently protected mice from AAA induced by (1) MR (mineralocorticoid receptor) agonist deoxycorticosterone acetate or aldosterone plus high salt intake and (2) angiotensin II infusion in hypercholesterolemia mice. Aortic BMAL1 was upregulated by deoxycorticosterone acetate-salt, and deletion of BMAL1 in SMCs selectively upregulated TIMP4 (tissue inhibitor of metalloproteinase 4) and suppressed deoxycorticosterone acetate-salt-induced MMP (matrix metalloproteinase) activation and elastin breakages. Moreover, BMAL1 bound to the. These results reveal an important, but previously unexplored, role of SMC BMAL1 in AAA. Moreover, these results identify TIMP4 as a novel target of BMAL1, which may mediate the AAA protective effect of SMC BMAL1 deletion.

Topics: Aldosterone; Angiotensin II; Animals; Aorta, Abdominal; Aortic Aneurysm, Abdominal; ARNTL Transcription Factors; Binding Sites; Desoxycorticosterone Acetate; Dilatation, Pathologic; Disease Models, Animal; Elastin; Male; Matrix Metalloproteinase 2; Matrix Metalloproteinase 9; Mice, Inbred C57BL; Mice, Knockout; Muscle, Smooth, Vascular; Myocytes, Smooth Muscle; Promoter Regions, Genetic; Sodium Chloride, Dietary; Tissue Inhibitor of Metalloproteinase-4; Tissue Inhibitor of Metalloproteinases; Transcription, Genetic

Abdominal aortic aneurysms (AAA) is a chronic inflammatory disease in which signal transducer and activator of transcription 3 (STAT3), and disintegrin and metalloproteinase 17 (ADAM17) play important roles. However, it remains unclear whether ursolic acid (UA), a natural pentacyclic triterpenoid carboxylic acid, can have an impact on STAT3 and ADAM17 and hence influence the formation of AAA. The objective of this study was to characterize the potential effect of UA on the pathogenesis of AAA and on STAT3 and ADAM17.. UA decreased the incidence of AngII-induced AAA in mice. UA alleviated the degradation of elastin fibers and inflammation and decreased the expression of MMP2, MMP9, ADAM17 and phospho-STAT3 (pSTAT3) in aorta of mice induced with AngII. UA inhibited the constitutive and stimuli-induced (AngII and tumor necrosis factor-α) expression of MMP2, MMP9, ADAM17 and pSTAT3 in vascular smooth muscle cells (VSMCs). Furthermore, UA decreased cell viability, and suppressed colony formation and wound healing in vitro.. We demonstrated that UA ameliorated the severity of AAA and exhibited an inhibitory effect on the expression of pSTAT3 and ADAM17. UA might emerge as a promising agent contributing to the prevention or treatment of AAA.

Topics: ADAM17 Protein; Angiotensin II; Animals; Anti-Inflammatory Agents; Aorta, Abdominal; Aortic Aneurysm, Abdominal; Cell Line; Cell Proliferation; Disease Models, Animal; Elastin; Male; Matrix Metalloproteinase 2; Matrix Metalloproteinase 9; Mice, Knockout, ApoE; Muscle, Smooth, Vascular; Myocytes, Smooth Muscle; Phosphorylation; Signal Transduction; STAT3 Transcription Factor; Triterpenes; Ursolic Acid; Vascular Remodeling; Wound Healing

Topics: Aminopropionitrile; Animals; Aorta, Thoracic; Aortic Aneurysm, Thoracic; Aortic Dissection; Cells, Cultured; Cytokine Receptor Common beta Subunit; Dilatation, Pathologic; Disease Models, Animal; Elastin; Extracellular Signal-Regulated MAP Kinases; Interleukin-3; JNK Mitogen-Activated Protein Kinases; Macrophages; Matrix Metalloproteinase 12; Mice, Inbred C57BL; Mice, Knockout; Signal Transduction; Transcription Factor AP-1; Up-Regulation

Arterial stiffness and wave reflection are important components of the ventricular afterload. Therefore, we aimed to assess the arterial wave characteristics and mechanical properties of the proximal pulmonary arteries (PAs) in the hypoxic pulmonary hypertensive rat model. After 21 days in normoxic or hypoxic chambers (24 animals/group), animals underwent transthoracic echocardiography and PA catheterization with a dual-tipped pressure and Doppler flow sensor wire. Wave intensity analysis was performed. Artery rings obtained from the pulmonary trunk, right and left PAs, and aorta were subjected to a tensile test to rupture. Collagen and elastin content were determined. In hypoxic rats, proximal PA wall thickness, collagen content, tensile strength per unit collagen, maximal elastic modulus, and wall viscosity increased, whereas the elastin-to-collagen ratio and arterial distensibility decreased. Arterial pulse wave velocity was also increased, and the increase was more prominent in vivo than ex vivo. Wave intensity was similar in hypoxic and normoxic animals with negligible wave reflection. In contrast, the aortic maximal elastic modulus remained unchanged, whereas wall viscosity decreased. In conclusion, there was no evidence of altered arterial wave propagation in proximal PAs of hypoxic rats while the extracellular matrix protein composition was altered and collagen tensile strength increased. This was accompanied by altered mechanical properties in vivo and ex vivo. NEW & NOTEWORTHY In rats exposed to chronic hypoxia, we have shown that pulse wave velocity in the proximal pulmonary arteries increased and pressure dependence of the pulse wave velocity was steeper in vivo than ex vivo leading to a more prominent increase in vivo.

Topics: Animals; Aorta; Arterial Pressure; Biomechanical Phenomena; Chronic Disease; Collagen; Disease Models, Animal; Elastic Modulus; Elastin; Hypertension, Pulmonary; Hypoxia; Male; Models, Cardiovascular; Pulmonary Artery; Pulse Wave Analysis; Rats, Sprague-Dawley; Tensile Strength; Time Factors; Vascular Remodeling; Vascular Stiffness; Viscosity

The pathogenesis of aortic aneurysm (AA) is associated with chronic inflammation in the aortic wall with increased levels of matrix metalloproteinases (MMPs). Clarithromycin (CAM) has been reported to suppresses MMP activity. In this study, we investigated whether CAM could prevent the formation and rupture of AA.. Male apolipoprotein E-deficient mice (28-30 weeks of age) were infused with angiotensin II for 28 days. CAM (100 mg/kg/d) or saline (as a control) was administered orally to the mice every day (CAM group, n = 13; control group, n = 13). After the administration period, the aortic diameter, elastin content, macrophage infiltration, MMP levels, and levels of inflammatory cytokines, including nuclear factor κB (NF-κB), were measured.. The aortic diameter was significantly suppressed in the CAM group (P < .001). No rupture death was observed in the CAM group in contrast to five deaths (38%) in the control group (P < .01). CAM significantly suppressed the degradation of aortic elastin (56.3% vs 16.5%; P < .001) and decreased the infiltration of inflammatory macrophages (0.05 vs 0.16; P < .01). Compared with the controls, the enzymatic activity of MMP-2 and MMP-9 was significantly reduced in the CAM group (MMP-2, 0.15 vs 0.56 [P < .01]; MMP-9, 0.12 vs 0.60 [P < .01]), and the levels of interleukin 1β (346.6 vs 1066.0; P < .05), interleukin 6 (128.4 vs 346.2; P < .05), and phosphorylation of NF-κB were also decreased (0.3 vs 2.0; P < .01).. CAM suppressed the progression and rupture of AA through the suppression of inflammatory macrophage infiltration, a reduction in MMP-2 and MMP-9 activity, and the inhibition of elastin degradation associated with the suppression of NF-κB phosphorylation.

Topics: Administration, Oral; Angiotensin II; Animals; Aorta; Aortic Aneurysm; Aortic Rupture; Cells, Cultured; Clarithromycin; Disease Models, Animal; Elastin; Inflammation Mediators; Interleukin-1beta; Interleukin-6; Macrophages; Male; Matrix Metalloproteinases, Secreted; Mice, Inbred C57BL; Mice, Knockout, ApoE; NF-kappa B; Phosphorylation; Vascular Remodeling

Development of right ventricular (RV) hypertension eventually contributes to RV and left ventricular (LV) myocardial fibrosis and dysfunction. The molecular mechanisms are not fully elucidated.. Pulmonary artery banding was used to induce RV hypertension in rats in vivo. Then, we evaluated cardiac function and regional remodeling 6 weeks after pulmonary artery banding. To further elucidate mechanisms responsible for regional cardiac remodeling, we also mimicked RV hypertensive stress by cyclic mechanical stretching applied to confluent cultures of cardiac fibroblasts, isolated from the RV free wall, septal hinge points, and LV free wall. Echocardiography and catheter evaluation demonstrated that rats in the pulmonary artery banding group developed RV hypertension with leftward septal displacement, LV compression, and increased LV end-diastolic pressures. Picrosirius red staining indicated that pulmonary artery banding induced marked RV fibrosis and dysfunction, with prominent fibrosis and elastin deposition at the septal hinge points but less LV fibrosis. These changes were associated with proportionally increased expressions of integrin-β1 and profibrotic signaling proteins, including phosphorylated Smad2/3 and transforming growth factor-β1. Moreover, mechanically stretched fibroblasts also expressed significantly increased levels of α-smooth muscle actin, integrin-β1, transforming growth factor-β1, collagen I deposition, and wrinkle formation on gel assays, consistent with myofibroblast transformation. These changes were not observed in parallel cultures of mechanically stretched fibroblasts, preincubated with the integrin inhibitor (BTT-3033).. Experimentally induced RV hypertension triggers regional RV, hinge-point, and LV integrin β1-dependent mechanotransduction signaling pathways that eventually trigger myocardial fibrosis via transforming growth factor-β1 signaling. Reduced LV fibrosis and preserved global function, despite geometrical and pressure aberrations, suggest a possible elastin-mediated protective mechanism at the septal hinge points.

Topics: Animals; Arterial Pressure; Cells, Cultured; Collagen Type I; Disease Models, Animal; Elastin; Fibrosis; Heart Ventricles; Hypertension, Pulmonary; Hypertrophy, Left Ventricular; Hypertrophy, Right Ventricular; Integrin beta1; Male; Mechanotransduction, Cellular; Pulmonary Artery; Rats, Sprague-Dawley; Transforming Growth Factor beta1; Ventricular Function, Left; Ventricular Function, Right; Ventricular Remodeling

Abdominal aortic aneurysm (AAA) is a vascular disease that results in rupture of the abdominal aorta. The risk factors for the development of AAA include smoking, male sex, hypertension, and age. AAA has a high mortality rate, but therapy for AAA is restricted to surgery in cases of large aneurysms. Clarifying the effect of dietary food on the development of AAA would be helpful for patients with AAAs. However, the relationship between dietary habits and the development of AAA is largely unknown. In our previous study, we demonstrated that adipocytes in vascular wall can induce the rupture of AAA. Therefore, we focused on the diet-induced abnormal triglyceride metabolism, which has the potential to drive AAA development. In this study, we have evaluated the effects of a high-sucrose diet on the development of AAA in a vascular hypoperfusion-induced animal model. A high sucrose diet induced high serum TG level and fatty liver. However, the AAA rupture risk and the AAA diameter were not significantly different between the control and high-sucrose groups. The intergroup differences in the elastin degradation score and collagen-positive area were insignificant. Moreover, matrix metalloproteinases, macrophages, and monocyte chemoattractant protein-1-positive areas did not differ significantly between groups. These results suggest that a high-sucrose diet does not affect the appearance of vascular adipocyte and AAA development under the vascular hypoperfusion condition.

Topics: Adipocytes; Aneurysm, Ruptured; Animals; Aortic Aneurysm, Abdominal; Collagen; Diet, Carbohydrate Loading; Dietary Sucrose; Disease Models, Animal; Elastin; Fatty Liver; Male; Rats, Sprague-Dawley; Risk Factors; Triglycerides

Patients undergoing deep vein thrombosis (VT) have over 30% recurrence, directly increasing their risk of post-thrombotic syndrome. Current murine models of inferior vena cava (IVC) VT model host one thrombosis event.. We aimed to develop a murine model to study IVC recurrent VT in mice.. An initial VT was induced using the electrolytic IVC model (EIM) with constant blood flow. This approach takes advantage of the restored vein lumen 21 days after a single VT event in the EIM demonstrated by ultrasound. We then induced a second VT 21 days later, using either EIM or an IVC ligation model for comparison. The control groups were a sham surgery and, 21 days later, either EIM or IVC ligation. IVC wall and thrombus were harvested 2 days after the second insult and analysed for IVC and thrombus size, gene expression of fibrotic markers, histology for collagen and Western blot for citrullinated histone 3 (Cit-H3) and fibrin.. Ultrasound confirmed the first VT and its progressive resolution with an anatomical channel allowing room for the second thrombus by day 21. As compared with a primary VT, recurrent VT has heavier walls with significant up-regulation of transforming growth factor-β (TGF-β), elastin, interleukin (IL)-6, matrix metallopeptidase 9 (MMP9), MMP2 and a thrombus with high citrullinated histone-3 and fibrin content.. Experimental recurrent thrombi are structurally and compositionally different from the primary VT, with a greater pro-fibrotic remodelling vein wall profile. This work provides a VT recurrence IVC model that will help to improve the current understanding of the biological mechanisms and directed treatment of recurrent VT.

Topics: Animals; Cells, Cultured; Disease Models, Animal; Elastin; Electrolytes; Fibrosis; Humans; Interleukin-6; Matrix Metalloproteinase 2; Matrix Metalloproteinase 9; Mice; Mice, Inbred C57BL; Postthrombotic Syndrome; Recurrence; Risk; Transforming Growth Factor beta; Vena Cava, Inferior; Venous Thrombosis

Aging leads to central artery stiffening and associated hemodynamic sequelae. Because healthy arteries exhibit differential geometry, composition, and mechanical behaviors along the central vasculature, we sought to determine whether wall structure and mechanical function differ across five vascular regions-the ascending and descending thoracic aorta, suprarenal and infrarenal abdominal aorta, and common carotid artery-in 20 versus 100-week-old male wild-type mice. Notwithstanding generally consistent changes across these regions, including a marked thickening of the arterial wall, diminished in vivo axial stretch, and loss of elastic energy storage capacity, the degree of changes tended to be slightly greater in abdominal than in thoracic or carotid vessels. Likely due to the long half-life of vascular elastin, most mechanical changes in the arterial wall resulted largely from a distributed increase in collagen, including thicker fibers in the media, and localized increases in glycosaminoglycans. Changes within the central arteries associated with significant increases in central pulse pressure and adverse changes in the left ventricle, including increased cardiac mass and decreased diastolic function. Given the similar half-life of vascular elastin in mice and humans but very different life-spans, there are important differences in the aging of central vessels across these species. Nevertheless, the common finding of aberrant matrix remodeling contributing to a compromised mechanical homeostasis suggests that studies of central artery aging in the mouse can provide insight into mechanisms and treatment strategies for the many adverse effects of vascular aging in humans.

Topics: Aging; Animals; Aorta, Abdominal; Aorta, Thoracic; Biomechanical Phenomena; Cardiovascular Diseases; Cardiovascular System; Carotid Arteries; Carotid Artery, Common; Diastole; Disease Models, Animal; Elastin; Extracellular Matrix Proteins; Hemodynamics; Homeostasis; Humans; Male; Mice; Models, Cardiovascular; Pressure; Recombinant Proteins; Stress, Mechanical; Time Factors; Vascular Stiffness

Age-related macular degeneration (AMD) is the leading cause of severe and irreversible central vision loss, and the primary site of AMD pathology is the retinal pigment epithelium (RPE). Geographic atrophy (GA) is an advanced form of AMD characterized by extensive RPE cell loss, subsequent degeneration of photoreceptors, and thinning of retina. This report describes the protective potential of a peptide derived from the αB crystallin protein using a sodium iodate (NaIO

Topics: alpha-Crystallin B Chain; Animals; Disease Models, Animal; Elastin; Eye; Intravitreal Injections; Iodates; Macular Degeneration; Mice; Neuroprotection; Neuroprotective Agents; Peptides

Particulate matter 2.5 (PM2.5) has proven to be associated with morbidity and mortality from cardiovascular diseases. However, whether PM2.5 could promote the formation of abdominal aortic aneurysm (AAA) is unclear. Present study aimed to explore the relationship between PM2.5 exposure and AAA development.. Ang Ⅱ-infused apoe. We found that PM2.5 could significantly increase the AAA incidence, the maximal abdominal aortic diameter and could promote the degradation of elastin. Additionally, the expression of senescence markers, P21 and P16 were also enhanced after PM2.5 exposure. We also found that PM2.5 significantly increased the AAA related pathological changes, MMP2 and MCP-1 expression in HASMCs. Meanwhile, PM2.5 could increase the expression of senescence markers P21, P16 and SA-β-gal activity, also the reactive oxygen species levels in vitro.. PM2.5 promoted the formation of AAA in an Ang Ⅱ-induced AAA model. The underlying mechanism might be cellular senescence after PM2.5 exposure.

Topics: Angiotensin II; Animals; Aorta, Abdominal; Aortic Aneurysm, Abdominal; Apolipoproteins E; beta-Galactosidase; Biomarkers; Cell Line; Chemokine CCL2; Cyclin-Dependent Kinase Inhibitor p16; Cyclin-Dependent Kinase Inhibitor p21; Disease Models, Animal; Elastin; Humans; Matrix Metalloproteinase 2; Mice; Mice, Inbred C57BL; Myocytes, Smooth Muscle; Particulate Matter; Reactive Oxygen Species

Uncontrolled hypertension is a primary risk factor for diverse cardiovascular diseases and thus remains responsible for significant morbidity and mortality. Hypertension leads to marked changes in the composition, structure, properties, and function of central arteries; hence, there has long been interest in quantifying the associated wall mechanics. Indeed, over the past 20 years there has been increasing interest in formulating mathematical models of the evolving geometry and biomechanical behavior of central arteries that occur during hypertension. In this paper, we introduce a new mathematical model of growth (changes in mass) and remodeling (changes in microstructure) of the aortic wall for an animal model of induced hypertension that exhibits both mechano-driven and immuno-mediated matrix turnover. In particular, we present a bilayered model of the aortic wall to account for differences in medial versus adventitial growth and remodeling and we include mechanical stress and inflammatory cell density as determinants of matrix turnover. Using this approach, we can capture results from a recent report of adventitial fibrosis that resulted in marked aortic maladaptation in hypertension. We submit that this model can also be used to identify novel hypotheses to guide future experimentation.

Topics: Adventitia; Animals; Aorta; Aorta, Thoracic; Arteries; Biomechanical Phenomena; Collagen; Computer Simulation; Disease Models, Animal; Elastin; Homeostasis; Humans; Hypertension; Immune System; Inflammation; Male; Mice; Models, Cardiovascular; Nonlinear Dynamics; Regression Analysis; Stress, Mechanical; Tunica Media; Vascular Stiffness

Central artery stiffening is recognized as a cardiovascular risk. The effects of hypertension and aging have been shown in human and animal models but the effect of salt is still controversial. We studied the effect of a high-salt diet on aortic stiffness in salt-sensitive spontaneously hypersensitive stroke-prone rats (SHRSP). Distensibility, distension, and β-stiffness were measured at thoracic and abdominal aortic sites in the same rats, using echotracking recording of the aortic diameter coupled with blood pressure (BP), in SHRSP-salt (5% salted diet, 5 weeks), SHRSP, and normotensive Wistar-Kyoto (WKY) rats. Hemodynamic parameters were measured at BP matched to that of WKY. Histological staining and immunohistochemistry were used for structural analysis. Hemodynamic isobaric parameters in SHRSP did not differ from WKY and only those from the abdominal aorta of SHRSP-salt presented decreased distensibility and increased stiffness compared with WKY and SHRSP. The abdominal and thoracic aortas presented similar thickening, increased fibrosis, and remodeling with no change in collagen content. SHRSP-salt presented a specific increased elastin disarray at the abdominal aorta level but a decrease in elastin content in the thoracic aorta. This study demonstrates the pro-stiffening effect of salt in addition to hypertension; it shows that only the abdominal aorta presents a specific pressure-independent stiffening, in which elastin disarray is likely a key mechanism.

Topics: Animals; Aorta, Abdominal; Aorta, Thoracic; Arterial Pressure; Disease Models, Animal; Elastin; Fibrosis; Hypertension; Male; Rats, Inbred SHR; Rats, Inbred WKY; Sodium Chloride, Dietary; Vascular Remodeling; Vascular Stiffness

The self-healing phenomenon can be found in the elastase-induced abdominal aortic aneurysm (AAA) model, and an enlarging AAA model was successfully induced by coarctation. Unfortunately, aortic coarctation in these enlarging models is generally not found in human AAA disease. This study aimed to create an experiment model of enlarging AAA in rabbits to better mimic human aortic aneurysm disease. Eighty-four male New Zealand white rabbits were randomly divided into three equal groups: two aneurysm groups (A and B) and a SHAM group. Aneurysm group rabbits underwent extrinsic aortic stenosis below the right renal artery and received a 10-minute incubation of 60 μl elastase (1 unit/μl). Absorbable suture was used in Group A and nonabsorbable cotton thread was used in Group B. A sham operation was performed in the SHAM group. Aortic diameter was measured after 1, 3, 7, and 15 weeks; thereafter animals were sacrificed for histopathological, immunohistochemical and quantitative studies. Two rabbits died at 29 and 48 days, respectively, after operation in Group B. All aneurysms formed and enlarged progressively by 3 weeks in the Aneurysm groups. However, diameter enlargement in Group A was significantly lower than that in Group B at 7 weeks. Aneurysm groups developed intimal hyperplasia; intima-media thickness (IMT) increased significantly by week 7, and aortic media thickness and intima-media ratio (IMR) increased significantly by week 15. Marked destruction of elastin fibers and smooth muscle cells (SMCs) occurred 1 week later and increased progressively thereafter. Intimal hyperplasia and SMCs content in Group A increased significantly by week 15 compared with Group B. Aneurysm groups exhibited strong expression of matrix metalloproteinases 2 and 9 and RAM11 by week 1, and decreased progressively thereafter. In conclusion, this novel rabbit AAA model enlarges progressively without coarctation and is capable of better mimicking human aortic aneurysm disease.

Topics: Angiography, Digital Subtraction; Animals; Aortic Aneurysm, Abdominal; Carotid Intima-Media Thickness; Disease Models, Animal; Elastic Tissue; Elastin; Humans; Male; Matrix Metalloproteinase 2; Matrix Metalloproteinase 9; Myocytes, Smooth Muscle; Pancreatic Elastase; Rabbits; Time Factors

Tamsulosin, an α. Abdominal aortic aneurysms were induced in WT C57BL/6 male mice (n = 9-18/group), using an established topical elastase abdominal aortic aneurysm model. Osmotic pumps were implanted in mice 5 days before operation to create the model, administering either low dose (0.125 µg/day tamsulosin), high dose (0.250µg/day tamsulosin), or vehicle treatments with and without topical application of elastase. Blood pressures were measured preoperatively and on postoperative days 0, 3, 7, and 14. On postoperative day 14, aortic diameter was measured before harvest. Sample aortas were prepared for histology and cytokine analysis.. Measurements of systolic blood pressure did not differ between groups. Mice treated with the low dose of tamsulosin and with the high dose of tamsulosin showed decreased aortic diameter compared with vehicle-treated control (93% ± 24 versus 94% ± 30 versus 132% ± 24, respectively; P = .0003, P = .0003). Cytokine analysis demonstrated downregulation of pro-inflammatory cytokines in both treatment groups compared with the control (P < .05). Histology exhibited preservation of elastin in both low- and high-dose tamsulosin-treated groups (P = .0041 and P = .0018, respectively).. Tamsulosin attenuates abdominal aortic aneurysm formation with increased preservation of elastin and decreased production of pro-inflammatory cytokines. Further studies are necessary to elucidate the mechanism by which tamsulosin attenuates abdominal aortic aneurysm pathogenesis.

Topics: Adrenergic alpha-1 Receptor Antagonists; Animals; Aorta, Abdominal; Aortic Aneurysm, Abdominal; Blood Pressure; Cytokines; Disease Models, Animal; Down-Regulation; Drug Evaluation, Preclinical; Elastin; Humans; Male; Mice; Mice, Inbred C57BL; Pancreatic Elastase; Tamsulosin; Treatment Outcome

Abdominal aortic aneurysm (AAA) is a vascular disease characterized by chronic inflammation in the infrarenal aorta. Epidemiologic data have clearly linked tobacco smoking to aneurysm formation and a faster rate of expansion. It suggested that nicotine, one of the main ingredients of tobacco, has been suggested to be associated with AAA development and rupture. In the condition where no established drugs are available; therefore, an effective approach to prevent the vascular damage from nicotine consumption may be the use of dietary functional food factors. However, little is known about the relationship between dietary components and AAA. In this study, we estimated the effect of dietary deoxyribonucleic acid (DNA) on the vascular wall. After habituation for 5 d, the mice were divided into four groups: control diet and distilled water group (C), DNA-Na diet and distilled water group (DNA), control diet and 0.5 mg/mL nicotine solution group (C-Nic), DNA-Na diet, and 0.5 mg/mL nicotine solution group (DNA-Nic). The dietary DNA attenuated the degradation of elastin fibers induced by nicotine administration. The areas stained positive for MMP-2 in the DNA-Nic group were significantly suppressed compared to C-Nic mice. These data suggest that the dietary DNA may prevent the weakening of the aortic wall via inhibition of the MMP-2-dependent pathway. In conclusion, we have revealed the protective effect of dietary DNA on the vascular pathology of nicotine-administrated mice. A nucleic acid-rich diet might be useful for people who consume nicotine via smoking, chewing tobacco, or nicotine patches.

Topics: Adventitia; Animals; Anti-Inflammatory Agents, Non-Steroidal; Antioxidants; Aorta, Abdominal; Aortic Aneurysm, Abdominal; Cardiovascular Agents; Dietary Supplements; Disease Models, Animal; DNA; Elastin; Endothelium, Vascular; Immunohistochemistry; Male; Matrix Metalloproteinase 2; Mice, Inbred C57BL; Nicotine; Oxidative Stress; Proteolysis

We have reported that nitrosonifedipine (NO-NIF), a photodegradation product of nifedipine, has strong antioxidant and endothelial protective effects, and can suppress several cardiovascular diseases in animal models. The objective of the present study was to investigate the effects of NO-NIF on aortic aneurysm formation.. The mice were infused with β-aminopropionitrile for 2 weeks and angiotensin II for 6 weeks to induce aortic aneurysm formation. The oxidative stress was measured by dihydroethidium staining and nitrotyrosine staining. The expressions of inflammation-related genes were assessed by quantitative real-time PCR and immunohistochemical staining. To clarify the mechanisms of how NO-NIF suppresses vascular cell adhesion molecule (VCAM)-1, endothelial cells were used in in vitro system.. NO-NIF suppressed pharmacologically induced the aortic aneurysm formation and aortic expansion without blood pressure changes. NO-NIF suppressed elastin degradation and matrix metalloproteinase-2 mRNA expression. NO-NIF suppressed the reactive oxygen species-cyclophilin A positive feedback loop. Upregulated mRNA expressions of inflammation-related genes and endothelial VCAM-1 were suppressed by NO-NIF co-treatment in aortae.. NO-NIF has the potential to be a new, nifedipine-derived therapeutic drug for suppressing aortic aneurysm formation by directly improving aortic structure with its strong ability to reduce oxidative stress and inflammation.

Topics: Aminopropionitrile; Angiotensin II; Animals; Antigens, Differentiation; Antioxidants; Aortic Aneurysm; Chemokine CCL2; Cyclophilins; Disease Models, Animal; Elastin; Endothelial Cells; Human Umbilical Vein Endothelial Cells; Humans; Male; Matrix Metalloproteinase 2; Mice; Nifedipine; Nitroso Compounds; Oxidative Stress; Photolysis; Reactive Oxygen Species; Vascular Cell Adhesion Molecule-1

Elastic fibers provide reversible elasticity to the large arteries and are assembled during development when hemodynamic forces are increasing. Mutations in elastic fiber genes are associated with cardiovascular disease. Mice lacking expression of the elastic fiber genes elastin ( Eln

Topics: Animals; Animals, Newborn; Aorta; Aortic Aneurysm; Arteries; Collagen Type VIII; Disease Models, Animal; Elastic Tissue; Elastin; Extracellular Matrix Proteins; Female; Gene Expression Regulation, Developmental; Insulin-Like Growth Factor Binding Protein 2; Joint Instability; Mice, Knockout; Oligonucleotide Array Sequence Analysis; Protein-Lysine 6-Oxidase; Skin Diseases, Genetic; Thrombospondin 1; Vascular Malformations

Abnormal mechanosensing of smooth muscle cells (SMCs) resulting from the defective elastin-contractile units has been suggested to drive the formation of thoracic aortic aneurysms; however, the precise molecular mechanism has not been elucidated.. The aim of this study was to identify the crucial mediator(s) involved in abnormal mechanosensing and propagation of biochemical signals during the aneurysm formation and to establish a basis for a novel therapeutic strategy.. We used a mouse model of postnatal ascending aortic aneurysms ( Fbln4. Thbs1 is a critical component of mechanotransduction, as well as a modulator of elastic fiber organization. Maladaptive upregulation of Thbs1 results in disruption of elastin-contractile units and dysregulation of actin cytoskeletal remodeling, contributing to the development of ascending aortic aneurysms in vivo. Thbs1 may serve as a potential therapeutic target for treating thoracic aortic aneurysms.

Topics: Actin Cytoskeleton; Aged; Aged, 80 and over; Animals; Aorta, Thoracic; Aortic Aneurysm, Thoracic; Cells, Cultured; Cofilin 2; Dilatation, Pathologic; Disease Models, Animal; Early Growth Response Protein 1; Elastic Tissue; Elastin; Extracellular Matrix Proteins; Female; Humans; Male; Mechanotransduction, Cellular; Mice, Knockout; Middle Aged; Muscle, Smooth, Vascular; Phosphoprotein Phosphatases; Phosphorylation; Pressoreceptors; Rats; Stress, Mechanical; Thrombospondin 1; Vascular Remodeling

Topics: Animals; Cyclophilin A; Cyclosporine; Disease Models, Animal; Drug Carriers; Drug Liberation; Elastin; HeLa Cells; Humans; Immunosuppressive Agents; Interleukin-2; Jurkat Cells; Male; Mice, Inbred BALB C; Mice, Inbred NOD; NFATC Transcription Factors; Peptides; Sjogren's Syndrome; Tears

Half of the female population over age 50 years will experience pelvic organ prolapse. We suggest a new approach based on tissue engineering principles to functionally reconstruct the anatomical structures of the pelvic floor. The aim of this study is to investigate the mechanical performance and effect on collagen and elastin production of a degradable mesh releasing basic fibroblast growth factor (bFGF). Implantation of biodegradable mesh with or without bFGF in their core has been conducted in 40 rats in an abdominal wall defect model. Samples were explanted after 4, 8, and 24 weeks, and tested for mechanical properties and the composition of connective tissue. The study showed an increase in mRNA expression for collagen-I (p = 0.0060) and collagen-III (p = 0.0086) in the 4 weeks group with bFGF. The difference was equalized at 8 and 24 weeks. No difference was found at any time for protein amount for collagen-I, collagen-III, and fibronectin. The amount of collagen decreased from 4 to 24 weeks but the fraction of collagen increased. The maximal load of the newly formed tissue showed no effect of bFGF at any time. Exclusively, histology showed a limited ingrowth of collagen fibers after 4 weeks with bFGF but signs of elastin fibers were seen at 24 weeks. The investigation showed that a biodegradable mesh promotes tissue formation with a promising strength. The mesh with bFGF did not represent any advantage on either long or short term in comparison to the mesh without bFGF. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 680-688, 2018.

Topics: Abdominal Wall; Absorbable Implants; Animals; Collagen Type I; Collagen Type III; Disease Models, Animal; Elastin; Ethylene Oxide; Female; Fibroblast Growth Factor 2; Fibronectins; Lactones; Pelvic Floor; Rats; Rats, Wistar; Surgical Mesh; Tissue Engineering

Abdominal aortic aneurysm (AAA) is a common age-related vascular disease characterized by progressive weakening and dilatation of the aortic wall. Thrombospondin-1 (TSP-1; gene Thbs1) is a member of the matricellular protein family important in the control of extracellular matrix (ECM) remodelling. In the present study, the association of serum TSP-1 concentration with AAA progression was assessed in 276 men that underwent repeated ultrasound for a median 5.5 years. AAA growth was negatively correlated with serum TSP-1 concentration (

Topics: Angiotensin II; Animals; Aorta, Abdominal; Aortic Aneurysm, Abdominal; Apolipoproteins E; Biomarkers; Cells, Cultured; Collagen Type III; Disease Models, Animal; Disease Progression; Elastin; Genetic Predisposition to Disease; Humans; Low Density Lipoprotein Receptor-Related Protein-1; Male; Matrix Metalloproteinase 9; Mice, Knockout; Odds Ratio; Phenotype; Proteolysis; Receptors, LDL; Risk Factors; Thrombospondin 1; Time Factors; Tumor Suppressor Proteins; Ultrasonography; Vascular Remodeling

A primary deficiency in predicting the progression and rupture-risk of abdominal aortic aneurysms (AAAs) is an inability to assign patient-specific, heterogeneous biomechanical properties to the remodelling aortic wall. Toward this end, we investigated possible correlations between three quantities having the potential for non-invasive measurement (diameter, wall thickness, and strain) and local wall microstructure within evolving experimental AAAs. AAAs were initiated in male C57BL/6J mice via in situ adventitial application of elastase and allowed to progress for 1-4 weeks. Regional in vitro Green strain was assessed using custom panoramic digital image correlation and compared to local geometry and histology. Diameter correlated mildly with elastin grade and collagen, when considering all circumferential locations and remodeling times. Normalized wall thickness correlated strongly with normalized collagen area fraction, though with outliers in highly cellular regions. Circumferential Green strain correlated strongly with elastin grade when measured over the range of 20-140 mmHg, though the correlation weakened across a physiologic range of 80-120 mmHg. Axial strain correlated strongly between in vitro and physiologic ranges of pressures. Circumferential heterogeneities render diameter a poor predictor of underlying regional microstructure. Thickness may indicate collagen content, though corrections are needed in regions of increased cellularity. In vitro circumferential strain predicts local functional elastin over large ranges of pressure, but there is a need to extend this correlation to clinically relevant pressures. Axial strain in the aneurysmal shoulder region may reflect the elastic integrity within the apical region of the lesion and should be explored as an indicator of disease severity.

Topics: Abdominal Wall; Animals; Aortic Aneurysm, Abdominal; Aortic Rupture; Collagen; Disease Models, Animal; Disease Progression; Elastin; Humans; Male; Mice; Mice, Inbred C57BL

Regular low-impact physical activity is generally allowed in patients with Marfan syndrome, a connective tissue disorder caused by heterozygous mutations in the fibrillin-1 gene. However, being above average in height encourages young adults with this syndrome to engage in high-intensity contact sports, which unfortunately increases the risk for aortic aneurysm and rupture, the leading cause of death in Marfan syndrome. In this study, we investigated the effects of voluntary (cage-wheel) or forced (treadmill) aerobic exercise at different intensities on aortic function and structure in a mouse model of Marfan syndrome. Four-week-old Marfan and wild-type mice were subjected to voluntary and forced exercise regimens or sedentary lifestyle for 5 mo. Thoracic aortic tissue was isolated and subjected to structural and functional studies. Our data showed that exercise improved aortic wall structure and function in Marfan mice and that the beneficial effect was biphasic, with an optimum at low intensity exercise (55-65% V̇o

Topics: Animals; Aorta, Thoracic; Aortic Aneurysm, Thoracic; Dilatation, Pathologic; Disease Models, Animal; Elasticity; Elastin; Male; Marfan Syndrome; Matrix Metalloproteinase 2; Mice; Mice, Inbred C57BL; Mice, Transgenic; Physical Conditioning, Animal

Aortic root aneurysm formation and subsequent dissection and/or rupture remain the leading cause of death in patients with Marfan syndrome. Our laboratory has reported that miR-29b participates in aortic root/ascending aorta extracellular matrix remodeling during early aneurysm formation in

Topics: Animals; Aortic Aneurysm; Disease Models, Animal; Disease Progression; Echocardiography; Elastin; Extracellular Matrix; Female; Fetal Therapies; Genetic Therapy; Male; Marfan Syndrome; Matrix Metalloproteinases; Mice, Inbred C57BL; Mice, Mutant Strains; MicroRNAs; Molecular Targeted Therapy; Prenatal Care

Thrombomodulin (TM), through its lectin-like domain (TMD1), sequesters proinflammatory high-mobility group box 1 (HMGB1) to prevent it from engaging the receptor for advanced glycation end product (RAGE) that sustains inflammation and tissue damage. Our previous study demonstrated that short-term treatment with recombinant TM containing all the extracellular domains (i.e., rTMD123) inhibits HMGB1-RAGE signaling and confers protection against CaCl. The therapeutic effects of recombinant TMD1 (rTMD1) and recombinant AAV vectors carrying the lectin-like domain of TM (rAAV-TMD1) were evaluated in the CaCl. In the CaCl. These findings corroborate the therapeutic potential of the TM lectin-like domain in AAA. The attenuation of angiotensin II-infused AAA by one-time delivery of rAAV-TMD1 provides a proof-of-concept validation of its application as potential gene therapy for aneurysm development.

Topics: Angiotensin II; Animals; Aorta, Abdominal; Aortic Aneurysm, Abdominal; Calcium Chloride; Cytokines; Dependovirus; Disease Models, Animal; Elastin; Genetic Therapy; Genetic Vectors; HMGB1 Protein; Macrophages; Male; Matrix Metalloproteinases; Mice, Knockout, ApoE; Oxidative Stress; Protein Domains; Receptor for Advanced Glycation End Products; Thrombomodulin; Vascular Remodeling

Autologous free flaps are the criterion standard for reconstructions of complex soft tissue defects; however, they are limited by donor-site morbidities. The arteriovenous (AV) loop model enables the generation of soft tissue constructs based on acellular dermal matrices with a functional microvasculature and minimal donor site morbidity. The ideal scaffold for AV loop-based tissue engineering has not been determined.. AV loops were placed into subcutaneous isolation chambers filled with either a collagen-elastin scaffold or a collagen-glycosaminoglycan scaffold in the thighs of rats. Matrix elasticity, neoangiogenesis, cell migration, and proliferation were compared after 14 and 28 days.. Mean vessel count and area had increased in both matrices at 28 compared with 14 days. Collagen-elastin matrices showed a higher mean vessel count and area compared with collagen-glycosaminoglycan matrices at 14 days. At 28 days, a more homogeneous vascular network and higher cell counts were observed in collagen-elastin matrices. Collagen-glycosaminoglycan matrices, however, exhibited less volume loss at day 28.. Collagen-based scaffolds are suitable for soft tissue engineering in conjunction with the AV loop technique. These scaffolds exhibit distinct patterns of angiogenesis, cell migration, and proliferation and may in the future serve as the basis of tissue-engineered free flaps as an individualized treatment concept for critical wounds.

Topics: Acellular Dermis; Animals; Collagen; Disease Models, Animal; Elastin; Female; Glycosaminoglycans; Graft Survival; Microvessels; Neovascularization, Physiologic; Random Allocation; Rats; Rats, Sprague-Dawley; Reference Values; Sensitivity and Specificity; Surgical Flaps; Tissue Engineering; Tissue Scaffolds; Wound Healing

Mutations in lysyl oxidase (LOX) are associated with thoracic aortic aneurysm and dissection (TAAD). Mice that do not express

Topics: Animals; Animals, Newborn; Aorta, Thoracic; Aortic Aneurysm, Thoracic; Arterial Pressure; Biomechanical Phenomena; Collagen; Dilatation, Pathologic; Disease Models, Animal; Elastin; Extracellular Matrix Proteins; Gene Expression Profiling; Gene Expression Regulation; Genetic Predisposition to Disease; Mechanotransduction, Cellular; Mice, Knockout; Phenotype; Protein-Lysine 6-Oxidase; Stress, Mechanical; Vascular Stiffness

We determined in patients with pulmonary arterial (PA) hypertension (PAH) whether in addition to increased production of elastase by PA smooth muscle cells previously reported, PA elastic fibers are susceptible to degradation because of their abnormal assembly.. Fibrillin-1 and elastin are the major components of elastic fibers, and fibrillin-1 binds bone morphogenetic proteins (BMPs) and the large latent complex of transforming growth factor-β1 (TGFβ1). Thus, we considered whether BMPs like TGFβ1 contribute to elastic fiber assembly and whether this process is perturbed in PAH particularly when the BMP receptor, BMPR2, is mutant. We also assessed whether in mice with. Disrupting BMPR2 impairs TGFβ1- and BMP4-mediated elastic fiber assembly and is of pathophysiologic significance in PAH.

Topics: Animals; Bone Morphogenetic Protein 4; Bone Morphogenetic Protein Receptors, Type I; Bone Morphogenetic Protein Receptors, Type II; Case-Control Studies; Cells, Cultured; Disease Models, Animal; Elastic Tissue; Elastin; Familial Primary Pulmonary Hypertension; Fibrillin-1; Fibroblasts; Genetic Predisposition to Disease; Humans; Hypertension, Pulmonary; Mice, 129 Strain; Mice, Inbred C57BL; Mice, Knockout; Mutation; Myocytes, Smooth Muscle; Phenotype; Pulmonary Artery; RNA Interference; Transfection; Transforming Growth Factor beta; Vascular Remodeling

To explore the role of microRNA (miR)-30a in the development of aortic dissection.. Human aortic specimens of aortic dissections and aneurysms were harvested. Aortic specimens from donors for heart transplantation served as controls. Rat aortic vascular smooth muscle cells (VSMCs) were transfected with agomiR-30a or antagomiR-30a, and control cells were incubated with empty vectors. Rats were pretreated with agomiR-30a or antagomiR-30a (5 × 10. Gene expression of miR-30a was much higher, and protein abundance of LOX and elastin was significantly lower, in the aortic dissection specimens (P < .05 vs controls). Transfection of agomiR-30a markedly decreased the luciferase activity of LOX in VSMCs of wild type, but not of LOX 3'-UTR mutant (P = .002). In cultured VSMCs, transfection of agomiR-30a dramatically enhanced the gene expression of miR-30a and down-regulated the protein abundance of LOX and elastin (P < .05 vs controls). Pretreatment with agomiR-30a in vivo enhanced miR-30a expression and down-regulated the protein abundance of LOX and elastin in rat aortas (P < .05 vs controls). The rate of dissection was significantly higher in rats pretreated with agomiR-30a (P = .003 vs controls).. Overexpression of miR-30a contributes to the development of aortic dissection, possibly by targeting LOX.

Topics: Animals; Aorta; Aortic Aneurysm; Aortic Dissection; Case-Control Studies; Cells, Cultured; Disease Models, Animal; Elastin; Gene Expression Regulation, Enzymologic; Humans; Male; MicroRNAs; Muscle, Smooth, Vascular; Myocytes, Smooth Muscle; Protein-Lysine 6-Oxidase; Rats, Sprague-Dawley; Up-Regulation

Elastin deficiency causes vascular stiffening, a leading risk for hypertension and chronic kidney disease (CKD). The mechanisms mediating hypertension and/or CKD pathogenesis due to elastin deficiency are poorly understood. Using the elastin heterozygous (Eln+/-) mouse model, we tested whether renal dysfunction due to elastin deficiency occurs independently of and precedes the development of hypertension. We assessed blood pressure and renal hemodynamics in 30-day and 12-week-old male and female mice. At P30, blood pressure of Eln+/- mice was similar to wild-type controls; however, renal blood flow was lower, whereas renal vascular resistance was augmented at baseline in Eln+/- mice. At 12 weeks, renal vascular resistance remained elevated while filtration fraction was higher in male Eln+/- relative to wild-type mice. Heterozygous mice showed isolated systolic hypertension that was evident only at nighttime. Acute salt loading with 6% dietary sodium increased daytime systolic blood pressure only in male Eln+/- mice, causing a rightward shift and blunted slope of the pressure-natriuresis curve. Renal interlobar artery basal tone and myogenic response to increasing intraluminal pressure at day 10 were similar, whereas they were augmented at day 30 and at 12 weeks old in Eln+/- mice, and normalized by the AT1R blocker, candesartan. Heterozygous mice also exhibited podocyte foot process damage that persisted even when blood pressure was normalized to wild-type levels with hydralazine. Thus, elastin insufficiency triggers structural defects and abnormal remodeling of renal vascular signaling involving AT1R-mediated vascular mechanotransduction and renal hyperfiltration with increased blood pressure sensitivity to dietary sodium contributing to systolic hypertension.

Topics: Angiotensin II Type 1 Receptor Blockers; Animals; Benzimidazoles; Biphenyl Compounds; Blood Pressure; Disease Models, Animal; Elastin; Female; Humans; Hypertension; Kidney; Male; Mechanotransduction, Cellular; Mice; Mice, Inbred C57BL; Mice, Transgenic; Receptor, Angiotensin, Type 1; Renal Elimination; Renal Insufficiency, Chronic; Signal Transduction; Sodium Chloride, Dietary; Tetrazoles; Vascular Resistance

Spatiotemporal changes in the extracellular matrix (ECM) were studied within abdominal aortic aneurysms (AAAs) generated in rats via elastase infusion. At 7, 14 and 21 days post-induction, AAA tissues were divided into proximal, mid- and distal regions, based on their location relative to the renal arteries and the region of maximal aortic diameter. Wall thicknesses differed significantly between the AAA spatial regions, initially increasing due to positive matrix remodelling and then decreasing due to wall thinning and compaction of matrix as the disease progressed. Histological images analysed using custom segmentation tools indicated significant differences in ECM composition and structure vs healthy tissue, and in the extent and nature of matrix remodelling between the AAA spatial regions. Histology and immunofluorescence (IF) labelling provided evidence of neointimal AAA remodelling, characterized by presence of elastin-containing fibres. This remodelling was effected by smooth muscle α-actin-positive neointimal cells, which transmission electron microscopy (TEM) showed to differ morphologically from medial SMCs. TEM of the neointima further showed the presence of elongated deposits of amorphous elastin and the presence of nascent, but not mature, elastic fibres. These structures appeared to be deficient in at least one microfibrillar component, fibrillin-1, which is critical to mature elastic fibre assembly. The substantial production of elastin and elastic fibre-like structures that we observed in the AAA neointima, which was not observed elsewhere within AAA tissues, provides a unique opportunity to capitalize on this autoregenerative phenomenon and direct it from the standpoint of matrix organization towards restoring healthy aortic matrix structure, mechanics and function. Copyright © 2014 John Wiley & Sons, Ltd.

Topics: Actins; Animals; Aorta; Aorta, Abdominal; Aortic Aneurysm, Abdominal; Disease Models, Animal; Elastic Tissue; Elastin; Extracellular Matrix; Fluorescent Antibody Technique; Muscle, Smooth, Vascular; Myocytes, Smooth Muscle; Pancreatic Elastase; Phenotype; Rats; Rats, Sprague-Dawley; Regeneration; Spatio-Temporal Analysis

Inflammation-mediated elastin destruction in the aortic medial layer is related to progression of abdominal aortic aneurysm (AAA). Epigallocatechin-3-gallate (EGCG), a major component of green tea polyphenols, reportedly increases elastin synthesis in vitro and may possess anti-inflammatory effects. We used a rat model to investigate whether EGCG could prevent AAA progression.. The abdominal aortic diameter was significantly smaller in the EGCG group than in the control group on day 28 (2.9 ± 0.2 vs 2.3 ± 0.1 mm; P < .0001). The medial layer wall thickness and elastin content were significantly greater in the EGCG group than in the control group on day 28 (68.4 ± 13.6 vs 46.7 ± 13.4 μm [P < .001] and 20.3 ± 4.6 vs 9.5 ± 3.6% [P < .0001], respectively). Gene expression levels of tropoelastin and lysyl oxidase were significantly higher in the EGCG group immediately before AAA induction, indicating promoted elastoregeneration by EGCG administration (tropoelastin: 0.59 ± 0.36 control vs 1.24 ± 0.36 EGCG [P < .05], lysyl oxidase: 0.77 ± 0.45 control vs 1.34 ± 0.4 EGCG [P < .05]) (fold increase). Gene expression levels of inflammatory cytokines, including tumor necrosis factor-α and interleukin-1β, were significantly downregulated in the EGCG group (1.82 ± 0.71 vs 0.97 ± 0.59 [P < .05] and 3.91 ± 3.24 vs 0.89 ± 0.59 [P < .05], respectively). On day 7, gene expression levels and gelatinolytic activity of matrix metalloproteinase 9 were significantly lower in the EGCG group (1.41 ± 0.86 vs 0.51 ± 0.42 [P < .05] and 1.00 ± 0.17 vs 0.29 ± 0.12 [P < .0001], respectively), whereas gene expression levels of tissue inhibitors of metalloproteinase-1 were significantly higher in the EGCG group (0.96 ± 0.11 vs 1.14 ± 0.09; P < .05).. EGCG attenuated AAA progression in a rat model by preserving the aortic thickness and elastin content of the medial layer through regeneration of elastin, as mediated by anti-inflammatory effects, and subsequent reduction of matrix metalloproteinase activity.

Topics: Administration, Oral; Animals; Anti-Inflammatory Agents; Aorta, Abdominal; Aortic Aneurysm, Abdominal; Calcium Chloride; Catechin; Collagen; Cytokines; Dilatation, Pathologic; Disease Models, Animal; Disease Progression; Elastin; Gene Expression Regulation; Inflammation Mediators; Male; Matrix Metalloproteinase 1; Matrix Metalloproteinase 9; Pancreatic Elastase; Phytotherapy; Plant Extracts; Plants, Medicinal; Polyphenols; Protein-Lysine 6-Oxidase; Rats, Sprague-Dawley; Tea; Time Factors; Tropoelastin

Ventral hernia repair remains a major clinical need. Herein, we formulated a type I collagen/elastin crosslinked blend (CollE) for the fabrication of biomimetic meshes for ventral hernia repair. To evaluate the effect of architecture on the performance of the implants, CollE was formulated both as flat sheets (CollE Sheets) and porous scaffolds (CollE Scaffolds). The morphology, hydrophylicity and in vitro degradation were assessed by SEM, water contact angle and differential scanning calorimetry, respectively. The stiffness of the meshes was determined using a constant stretch rate uniaxial tensile test, and compared to that of native tissue. CollE Sheets and Scaffolds were tested in vitro with human bone marrow-derived mesenchymal stem cells (h-BM-MSC), and finally implanted in a rat ventral hernia model. Neovascularization and tissue regeneration within the implants was evaluated at 6weeks, by histology, immunofluorescence, and q-PCR. It was found that CollE Sheets and Scaffolds were not only biomechanically sturdy enough to provide immediate repair of the hernia defect, but also promoted tissue restoration in only 6weeks. In fact, the presence of elastin enhanced the neovascularization in both sheets and scaffolds. Overall, CollE Scaffolds displayed mechanical properties more closely resembling those of native tissue, and induced higher gene expression of the entire marker genes tested, associated with de novo matrix deposition, angiogenesis, adipogenesis and skeletal muscles, compared to CollE Sheets. Altogether, this data suggests that the improved mechanical properties and bioactivity of CollE Sheets and Scaffolds make them valuable candidates for applications of ventral hernia repair.. Due to the elevated annual number of ventral hernia repair in the US, the lack of successful grafts, the design of innovative biomimetic meshes has become a prime focus in tissue engineering, to promote the repair of the abdominal wall, avoid recurrence. Our meshes (CollE Sheets and Scaffolds) not only showed promising mechanical performance, but also allowed for an efficient neovascularization, resulting in new adipose and muscle tissue formation within the implant, in only 6weeks. In addition, our meshes allowed for the use of the same surgical procedure utilized in clinical practice, with the commercially available grafts. This study represents a significant step in the design of bioactive acellular off-the-shelf biomimetic meshes for ventral hernia repair.

Topics: Adult; Animals; Biomimetic Materials; Collagen; Disease Models, Animal; Elastin; Female; Hernia, Ventral; Humans; Male; Materials Testing; Mesenchymal Stem Cells; Rats; Rats, Inbred Lew; Surgical Mesh

Vocal fold injury results in severe voice alteration that limits occupational function and social interaction. An ovine model of laryngeal injury has been developed, validated and utilized to examine laryngeal wound healing and the effect of a novel collagen inhibitor (halofuginone) on surgical wound healing. The study design includes basic research and animal model.. An ovine laryngeal model was utilized to study controlled vocal fold injury and healing. Twenty-five sheep were divided into five groups. Sheep underwent right vocal fold injury preceded or followed by administration of halofuginone orally, topically or intralesionally. Biopsies were taken at commencement, 1 month and larynges explanted at 3 months. Specimens were examined for elastin and collagen density and epithelial changes. Pearson correlation statistics and Student's t-tests were used to assess inter-relationships.. All sheep tolerated halofuginone. One sheep death occurred in an untreated sheep. Vocal fold tissue demonstrated a predictable histological response to injury. Elastin was significantly reduced post-injury in the glottis. Halofuginone administered orally for 10 weeks prevented elastin loss and demonstrated a trend of reducing collagen density post-injury.. In an ovine laryngeal injury model, administration of a fibrosis inhibitor resulted in altered elastin and collagen deposition after injury in the glottis. Further investigation is warranted to examine whether these tissue changes affect vocal fold dynamics.

Topics: Administration, Oral; Administration, Topical; Animals; Collagen; Disease Models, Animal; Elastin; Fibrosis; Injections, Intralesional; Piperidines; Quinazolinones; Sheep; Treatment Outcome; Vocal Cords; Wound Healing

Abdominal aortic aneurysm (AAA) is a life-threatening vascular pathology, the pathogenesis of which is closely related to oxidative stress. However, an effective pharmaceutical treatment is lacking because the exact cause of AAA remains unknown. Here, we aimed at delineating the role of the paraoxonases (PONs) gene cluster (PC), which prevents atherosclerosis through the detoxification of oxidized substrates, in AAA formation.. PC transgenic (Tg) mice were crossed to an Apoe. Our findings reveal, for the first time, a protective role of the PC in AAA formation and suggest PONs as promising targets for AAA prevention.

Topics: Angiotensin II; Animals; Aorta, Abdominal; Aortic Aneurysm, Abdominal; Apolipoproteins E; Aryldialkylphosphatase; Cells, Cultured; Disease Models, Animal; Elastin; Extracellular Matrix; Genetic Predisposition to Disease; Humans; Matrix Metalloproteinase 2; Matrix Metalloproteinase 9; Mice; Mice, Inbred C57BL; Mice, Knockout; Mice, Transgenic; Multigene Family; Muscle, Smooth, Vascular; Myocytes, Smooth Muscle; Oxidative Stress; Phenotype; Proteolysis; Reactive Oxygen Species; Signal Transduction

Numerous etiological studies have established positive clinical association between hypertension and vascular dementia (VaD). Lactobacillus paracasei subsp. paracasei NTU 101-fermented products have been shown to decrease vascular risk factors such as hypertension, atherosclerosis, hyperlipidemia and obesity.. This study investigated the effect of ethanol extract of Lactobacillus paracasei subsp. paracasei NTU 101-fermented products (NTU101F) in hypertension-induced VaD in rats.. Hypertension was promoted by subcutaneous injection of deoxycorticosterone acetate (DOCA, 25 mg/kg body weight/day, twice a week) and substitution of drinking water with 1.0% NaCl and 0.2% KCl. The NTU101F groups (0.5, 1.0, and 5.0) administered NTU101F at the concentrations 11, 22, and 110 mg/kg body weight/day, respectively, starting from day 51 day of DOCA-salt treatment. Morris water maze (MWM) was used for testing learning and memory. Different biochemical estimations were used to assess oxidative stress and inflammatory response in hippocampus.. Oral administration of NTU101F in DOCA-salt hypertension-induced VaD rats resulted in a significant decrease in blood pressure by 18.3-23.2% (p < 0.001), which was regulated by increasing eNOS density (about 3-fold) in the aorta, promoting NO production, and decreasing of matrix metallopeptidase 9 activity (about 2-fold) in the hippocampus, in addition to improve the kidney function and structure, decrease escape latency and increase the times spent in the target quadrant by 23.5-27.8% (p < 0.05).. Overall, our findings suggest that NTU101F could exert neuroprotection in the brain and attenuate hypertension-induced VaD.

Topics: Animals; Aorta; Behavior, Animal; Blood Pressure; Cultured Milk Products; Cytokines; Dementia; Desoxycorticosterone Acetate; Dietary Supplements; Disease Models, Animal; Elastin; Escape Reaction; Hippocampus; Hypertension; Inflammation Mediators; Kidney; Lipid Peroxidation; Male; Matrix Metalloproteinase 9; Maze Learning; Memory; Nitric Oxide; Nitric Oxide Synthase Type III; Oxidative Stress; Rats, Wistar; Time Factors

MicroRNA-145 (miR-145) has been implicated in vascular smooth muscle cell differentiation, but the underlying mechanisms have not been fully understood, especially their role in abdominal aortic aneurysm (AAA) expansion. Here, we sought to explore and define the mechanisms of miR-145 function in the experimental AAA models in AngII-infused ApoE. miR-145 was overexpressed in ApoE. In vivo overexpression of miR-145 by lentivirus infection greatly decreased the incidence of AAA, maximum abdominal aortic diameter, and elastin degradation, accompanied with downregulation of MMP2 activation in AngII-infused ApoE. These data suggest that regulation of expression of miR-145 may be a potential therapeutic option for vascular disease progression such as AAA expansion.

Topics: Angiotensin II; Animals; Aortic Aneurysm, Abdominal; Apolipoproteins E; Collagen; Disease Models, Animal; Elastin; Gene Expression Regulation, Enzymologic; Lentivirus; Matrix Metalloproteinase 2; Mice; Mice, Knockout; MicroRNAs; Transduction, Genetic; Up-Regulation

Abdominal aortic aneurysm (AAA) is a common aortic disease with a progressive nature. There is no approved pharmacological treatment to effectively slow aneurysm growth or prevent rupture. Necroptosis is a form of programmed necrosis that is regulated by receptor-interacting protein kinases (RIPs). We have recently demonstrated that the lack of RIP3 in mice prevented aneurysm formation. The goal of the current study is to test whether perturbing necroptosis affects progression of existing aneurysm using the RIP1 inhibitors Necrostatin-1 (Nec-1) and an optimized form of Nec-1, 7-Cl-O-Nec-1 (Nec-1s). Seven days after aneurysm induction by elastase perfusion, mice were randomly administered DMSO, Nec-1 (3.2 mg/kg/day) and Nec-1s (1.6 mg/kg/day) via intraperitoneal injection. Upon sacrifice on day 14 postaneurysm induction, the aortic expansion in the Nec-1s group (64.12 ± 4.80%) was significantly smaller than that of the DMSO group (172.80 ± 13.68%) (P < 0.05). The mean aortic diameter of Nec-1 treated mice appeared to be smaller (121.60 ± 10.40%) than the DMSO group, though the difference was not statistically significant (P = 0.1). Histologically, the aortic structure of Nec-1s-treated mice appeared normal, with continuous and organized elastin laminae and abundant αActin-expressing SMCs. Moreover, Nect-1s treatment diminished macrophage infiltration and MMP9 accumulation and increased aortic levels of tropoelastin and lysyl oxidase. Together, our data suggest that pharmacological inhibition of necroptosis with Nec-1s stabilizes pre-existing aneurysms by diminishing inflammation and promoting connective tissue repair.

Topics: Animals; Anti-Inflammatory Agents; Aortic Aneurysm, Abdominal; Apoptosis; Cardiovascular Agents; Cell Movement; Disease Models, Animal; Elastin; Gene Expression Regulation; GTPase-Activating Proteins; Humans; Imidazoles; Indoles; Injections, Intraperitoneal; Macrophages; Male; Matrix Metalloproteinase 9; Mice; Mice, Inbred C57BL; Myocytes, Smooth Muscle; Necrosis; Pancreatic Elastase; Protein-Lysine 6-Oxidase; Tropoelastin

Williams syndrome is characterized by obstructive aortopathy attributable to heterozygous loss of. We quantified determinants of luminal stenosis in thoracic aortas of. Deficient circumferential growth is the predominant mechanism for moderate obstructive aortic disease resulting from partial elastin deficiency. Our findings suggest that diverse aortic manifestations in Williams syndrome result from graded elastin content, and SMC hyperplasia causing medial expansion requires additional elastin loss superimposed on

Topics: Adult; Animals; Aorta, Thoracic; Aortic Diseases; Cell Proliferation; Cells, Cultured; Collagen; Constriction, Pathologic; Disease Models, Animal; Elastin; Fibrosis; Genetic Predisposition to Disease; Humans; Hyperplasia; Male; Mice, Inbred C57BL; Mice, Knockout; Middle Aged; Muscle, Smooth, Vascular; Myocytes, Smooth Muscle; Phenotype; Time Factors; Vascular Stiffness; Vasoconstriction; Williams Syndrome

Emphysema is the major component of chronic obstructive pulmonary disease (COPD). During emphysema, elastin breakdown in the lung tissue originates from the release of large amounts of elastase by inflammatory cells. Elevated levels of elastin-derived peptides (EP) reflect massive pulmonary elastin breakdown in COPD patients. Only the EP containing the GXXPG conformational motif with a type VIII β-turn are elastin receptor ligands inducing biological activities. In addition, the COOH-terminal glycine residue of the GXXPG motif seems a prerequisite to the biological activity. In this study, we endotracheally instilled C57BL/6J mice with GXXPG EP and/or COOH-terminal glycine deleted-EP whose sequences were designed by molecular dynamics and docking simulations. We investigated their effect on all criteria associated with the progression of murine emphysema. Bronchoalveolar lavages were recovered to analyze cell profiles by flow cytometry and lungs were prepared to allow morphological and histological analysis by immunostaining and confocal microscopy. We observed that exposure of mice to EP elicited hallmark features of emphysema with inflammatory cell accumulation associated with increased matrix metalloproteinases and desmosine expression and of remodeling of parenchymal tissue. We also identified an inactive COOH-terminal glycine deleted-EP that retains its binding-activity to EBP and that is able to inhibit the in vitro and in vivo activities of emphysema-inducing EP. This study demonstrates that EP are key actors in the development of emphysema and that they represent pharmacological targets for an alternative treatment of emphysema based on the identification of EP analogous antagonists by molecular modeling studies.

Topics: Animals; Bronchoalveolar Lavage Fluid; Collagen; Disease Models, Animal; Elastin; Mice, Inbred C57BL; Pancreatic Elastase; Peptides; Pulmonary Emphysema; Receptors, Cell Surface

Antenatal inflammation and preterm birth are associated with the development of airway diseases such as wheezing and asthma. Utilizing a newborn mouse model, we assessed the effects of maternal inflammation and postnatal hyperoxia on the neonatal airway.. Pregnant C57/Bl6 dams were injected with lipopolysaccharide (LPS) or saline on embryonic day 16. Offspring were placed in room air or hyperoxia (50% O2) for 7 d and then returned to normoxia. Airway mechanics, histology, and laser capture micro-dissection (LCM) were performed.. At postnatal day 21, maternal LPS- and 50% O2-exposed pups exhibited increased resistance and decreased compliance compared to 21% O2 pups; however their effects were not synergistic. LPS and hyperoxia each increased the thickness of airway smooth muscle (ASM), but not the airway epithelial layer. Structural changes were largely limited to the conducting airways. Upregulation of inflammatory markers in the lung was observed at birth. LCM revealed increased collagen-3, transforming growth factor β, and connective tissue growth factor expression with LPS and hyperoxia within the ASM layer.. These novel studies provide functional, structural, and molecular evidence that antenatal inflammation is detrimental to the developing airway. Exposure to moderate hyperoxia does not exacerbate LPS effects on the airway.

Topics: Airway Remodeling; Animals; Animals, Newborn; Body Weight; Collagen; Disease Models, Animal; Dose-Response Relationship, Drug; Elastin; Female; Hyperoxia; Inflammation; Lipopolysaccharides; Lung; Methacholine Chloride; Mice; Mice, Inbred C57BL; Oxygen; Pregnancy; Pregnancy, Animal; Respiration; Respiratory System

Atherogenesis is a multifactorial pathologic process influenced by genetics and environmental factors such as diet, exercise, stress, and other exposures. Estrogen receptors (ER) are expressed in cells of the arterial wall, suggesting that estrogen receptor ligands (estradiol, natural and pharmacologic ligands) may directly affect arterial biology and atherogenesis. Ligand bound estrogen receptor alpha and beta (ERα, ERβ) can influence physiology through direct binding to estrogen response elements in the DNA, through interactions with other transcription factors such as NF-κB, or through rapid effects not dependent on gene expression changes but instead through non-nuclear membrane sites involving ERα, ERβ, or G-coupled protein ER (GPER1). Elucidation of potential direct effects of estrogens on the artery wall requires careful evaluation of arterial biologic responses to estrogens. We have developed a comprehensive approach to understand the mechanisms of estrogen action which employs histologic measures of the size and other characteristics of atherosclerotic lesions, immunohistochemical assessments of cellular composition, evaluation of chemical, molecular, and genomic changes in the arterial environment, and determination of the relationships between arterial estrogen receptor expression and atherogenesis. This approach can provide important insights into the mechanisms of action of estrogen and other mediators of atherogenesis.

Topics: Animals; Arteries; Atherosclerosis; Biomarkers; Collagen; Disease Models, Animal; Elastin; Estrogens; Frozen Sections; Gene Expression Regulation; Immunohistochemistry; Lipids; Paraffin Embedding; Plaque, Atherosclerotic; Receptors, Estrogen; Tissue Fixation; Vascular Calcification; Workflow

Marfan syndrome (MFS) is a multi-system connective tissue disorder that results from mutations to the gene that codes the elastin-associated glycoprotein fibrillin-1. Although elastic fibers are compromised throughout the arterial tree, the most severe phenotype manifests in the ascending aorta. By comparing biaxial mechanics of the ascending and descending thoracic aorta in a mouse model of MFS, we show that aneurysmal propensity correlates well with both a marked increase in circumferential material stiffness and an increase in intramural shear stress despite a near maintenance of circumferential stress. This finding is corroborated via a comparison of the present results with previously reported findings for both the carotid artery from the same mouse model of MFS and for the thoracic aorta from another model of elastin-associated glycoprotein deficiency that does not predispose to thoracic aortic aneurysms. We submit that the unique biaxial loading of the ascending thoracic aorta conspires with fibrillin-1 deficiency to render this aortic segment vulnerable to aneurysm and rupture.

Topics: Animals; Aorta, Thoracic; Aortic Aneurysm, Thoracic; Disease Models, Animal; Elastic Tissue; Elastin; Fibrillin-1; Humans; Male; Marfan Syndrome; Mechanical Phenomena; Mice; Stress, Mechanical; Weight-Bearing

Chronic inflammation and degradation of elastin are the main processes in the development of abdominal aortic aneurysm (AAA). Recent studies show that zinc has an anti-inflammatory effect. Based on these, zinc may render effective therapy for the treatment of the AAA. Currently, we want to investigate the effects of zinc on AAA progression and its related molecular mechanism. Rat AAA models were induced by periaortic application of CaCl2. AAA rats were treated by daily intraperitoneal injection of ZnSO4 or vehicle alone. The aorta segments were collected at 4 weeks after surgery. The primary rat aortic vascular smooth muscle cells (VSMCs) were stimulated with TNF-α alone or with ZnSO4 for 3 weeks. The results showed that zinc supplementation significantly suppressed the CaCl2-induced expansion of the abdominal aortic diameter, as well as a preservation of medial elastin fibers in the aortas. Zinc supplementation also obviously attenuated infiltration of the macrophages and lymphocytes in the aortas. In addition, zinc reduced MMP-2 and MMP-9 production in the aortas. Most importantly, zinc treatment significantly induced A20 expression, along with inhibition of the NF-κB canonical signaling pathway in vitro in VSMCs and in vivo in rat AAA. This study demonstrated, for the first time, that zinc supplementation could prevent the development of rat experimental AAA by induction of A20-mediated inhibition of the NF-κB canonical signaling pathway.

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Aorta, Abdominal; Aortic Aneurysm, Abdominal; Cells, Cultured; Disease Models, Animal; DNA-Binding Proteins; Elastin; I-kappa B Kinase; I-kappa B Proteins; Inflammation; Male; Matrix Metalloproteinase 2; Matrix Metalloproteinase 9; Matrix Metalloproteinase Inhibitors; Myocytes, Smooth Muscle; NF-kappa B; NF-KappaB Inhibitor alpha; Rats; Rats, Wistar; Signal Transduction; Tumor Necrosis Factor alpha-Induced Protein 3; Zinc Sulfate

Kawasaki disease (KD) is the most common cause of acquired cardiac disease in US children. In addition to coronary artery abnormalities and aneurysms, it can be associated with systemic arterial aneurysms. We evaluated the development of systemic arterial dilatation and aneurysms, including abdominal aortic aneurysm (AAA) in the Lactobacillus casei cell-wall extract (LCWE)-induced KD vasculitis mouse model.. We discovered that in addition to aortitis, coronary arteritis and myocarditis, the LCWE-induced KD mouse model is also associated with abdominal aorta dilatation and AAA, as well as renal and iliac artery aneurysms. AAA induced in KD mice was exclusively infrarenal, both fusiform and saccular, with intimal proliferation, myofibroblastic proliferation, break in the elastin layer, vascular smooth muscle cell loss, and inflammatory cell accumulation in the media and adventitia. Il1r(-/-), Il1a(-/-), and Il1b(-/-) mice were protected from KD associated AAA. Infiltrating CD11c(+) macrophages produced active caspase-1, and caspase-1 or NLRP3 deficiency inhibited AAA formation. Treatment with interleukin (IL)-1R antagonist (Anakinra), anti-IL-1α, or anti-IL-1β mAb blocked LCWE-induced AAA formation.. Similar to clinical KD, the LCWE-induced KD vasculitis mouse model can also be accompanied by AAA formation. Both IL-1α and IL-1β play a key role, and use of an IL-1R blocking agent that inhibits both pathways may be a promising therapeutic target not only for KD coronary arteritis, but also for the other systemic arterial aneurysms including AAA that maybe seen in severe cases of KD. The LCWE-induced vasculitis model may also represent an alternative model for AAA disease.

Topics: Animals; Aorta, Abdominal; Aortic Aneurysm, Abdominal; Aortitis; Caspase 1; Cell Proliferation; Cell Wall; Dilatation, Pathologic; Disease Models, Animal; Elastin; Female; Gene Expression Profiling; Genotype; Humans; Interleukin 1 Receptor Antagonist Protein; Interleukin-1alpha; Interleukin-1beta; Lacticaseibacillus casei; Macrophages; Male; Mice, Inbred C57BL; Mice, Knockout; Mucocutaneous Lymph Node Syndrome; Muscle, Smooth, Vascular; Myocytes, Smooth Muscle; NLR Family, Pyrin Domain-Containing 3 Protein; Phenotype; Receptors, Interleukin-1 Type I; Signal Transduction; Time Factors

Abdominal aortic aneurysm (AAA) is a major cause of morbidity and mortality; however, the mechanisms that are involved in disease initiation and progression are incompletely understood. Extracellular matrix proteins play an integral role in modulating vascular homeostasis in health and disease. Here, we determined that the expression of the matricellular protein CCN3 is strongly reduced in rodent AAA models, including angiotensin II-induced AAA and elastase perfusion-stimulated AAA. CCN3 levels were also reduced in human AAA biopsies compared with those in controls. In murine models of induced AAA, germline deletion of Ccn3 resulted in severe phenotypes characterized by elastin fragmentation, vessel dilation, vascular inflammation, dissection, heightened ROS generation, and smooth muscle cell loss. Conversely, overexpression of CCN3 mitigated both elastase- and angiotensin II-induced AAA formation in mice. BM transplantation experiments suggested that the AAA phenotype of CCN3-deficient mice is intrinsic to the vasculature, as AAA was not exacerbated in WT animals that received CCN3-deficient BM and WT BM did not reduce AAA severity in CCN3-deficient mice. Genetic and pharmacological approaches implicated the ERK1/2 pathway as a critical regulator of CCN3-dependent AAA development. Together, these results demonstrate that CCN3 is a nodal regulator in AAA biology and identify CCN3 as a potential therapeutic target for vascular disease.

Topics: Angiotensin II; Animals; Aortic Aneurysm, Abdominal; Disease Models, Animal; Elastin; Gene Deletion; Humans; MAP Kinase Signaling System; Mice; Mice, Knockout; Nephroblastoma Overexpressed Protein; Pancreatic Elastase

Although high-mobility group box-1 (HMGB1) levels in tracheal aspirates are associated with the pathological features of bronchopulmonary dysplasia (BPD), the role of HMGB1 in the terminal stage of abnormal alveologenesis has not yet been understood. In this study, we addressed the role of HMGB1 in the elastogenesis disruption in the lungs of newborn mice with BPD. We found that elevations of whole lung HMGB1 level were associated with impaired alveolar development and aberrant elastin production in 85% O2-exposed lungs. HMGB1 neutralizing antibody attenuated the structural disintegration developed in hyperoxia-damaged lungs. Furthermore, HMGB1 inhibition rescued the neutrophil influx in hyperoxia-injured lung and partially abolished the mRNA level of the proinflammatory mediators, interleukin (IL)-1β and transforming growth factor (TGF)-β1. These data suggested that pulmonary HMGB1 plays an important role in the disruption of elastogenesis in the terminal stage of lung development through reduced pulmonary inflammatory response.

Topics: Animals; Animals, Newborn; Antibodies, Neutralizing; Bronchopulmonary Dysplasia; Disease Models, Animal; Elastin; Gene Expression Regulation, Developmental; HMGB1 Protein; Humans; Hyperoxia; Interleukin-1beta; Mice; Mice, Inbred C57BL; Neutrophils; Oxygen; Pulmonary Alveoli; Transforming Growth Factor beta1

Clinical management of abdominal aortic aneurysm (AAA) is currently limited to elective surgical repair because an effective pharmacotherapy is still awaited. Inhibition of histone deacetylase (HDAC) activity could be a promising therapeutic option in cardiovascular diseases. We aimed to characterise HDAC expression in human AAA and to evaluate the therapeutic potential of class I and IIa HDAC inhibitors in the AAA model of angiotensin II (Ang II)-infused apolipoprotein-E-deficient (ApoE(-/-)) mice. Real-time PCR, western blot and immunohistochemistry evidenced an increased expression of HDACs 1, 2 (both class I), 4 and 7 (both class IIa) in abdominal aorta samples from patients undergoing AAA open repair (n=22) compared with those from donors (n=14). Aortic aneurysms from Ang-II-infused ApoE(-/-) mice exhibited a similar HDAC expression profile. In these animals, treatment with a class I HDAC inhibitor (MS-275) or a class IIa inhibitor (MC-1568) improved survival, reduced the incidence and severity of AAA and limited aneurysmal expansion evaluated by Doppler ultrasonography. These beneficial effects were more potent in MC-1568-treated mice. The disorganisation of elastin and collagen fibres and lymphocyte and macrophage infiltration were effectively reduced by both inhibitors. Additionally, HDAC inhibition attenuated the exacerbated expression of pro-inflammatory markers and the increase in metalloproteinase-2 and -9 activity induced by Ang II in this model. Therefore, our data evidence that HDAC expression is deregulated in human AAA and that class-selective HDAC inhibitors limit aneurysm expansion in an AAA mouse model. New-generation HDAC inhibitors represent a promising therapeutic approach to overcome human aneurysm progression.

Topics: Angiotensin II; Animals; Aorta, Abdominal; Aortic Aneurysm, Abdominal; Apolipoproteins E; Biomarkers; Collagen; Disease Models, Animal; Disease Progression; Elastin; Enzyme Induction; Female; Histone Deacetylase Inhibitors; Histone Deacetylases; Humans; Inflammation; Male; Matrix Metalloproteinase 2; Matrix Metalloproteinase 9; Middle Aged; Severity of Illness Index; Up-Regulation

Structural remodeling of the microvasculature occurs during obesity. Based on observations that impaired H2S signaling is associated with cardiovascular pathologies, the current study was designed to test the hypothesis that altered H2S homeostasis is involved in driving the remodeling process in a diet-induced mouse model of obesity. The structural and passive mechanical properties of mesenteric resistance arterioles isolated from 30-wk-old lean and obese mice were assessed using pressure myography, and vessel H2S levels were quantified using the H2S indicator sulfidefluor 7-AM. Remodeling gene expression was assessed using quantitative RT-PCR, and histological staining was used to quantify vessel collagen and elastin. Obesity was found to be associated with decreased vessel H2S concentration, inward hypertrophic remodeling, altered collagen-to-elastin ratio, and reduced vessel stiffness. In addition, mRNA levels of fibronectin, collagen types I and III, matrix metalloproteinases 2 and 9, and tissue inhibitor of metalloproteinase 1 were increased and elastin was decreased by obesity. Evidence that decreased H2S was responsible for the genetic changes was provided by experiments in which H2S levels were manipulated, either by inhibition of the H2S-generating enzyme cystathionine γ-lyase with dl-propargylglycine or by incubation with the H2S donor GYY4137. These data suggest that, during obesity, depletion of H2S is involved in orchestrating the genetic changes underpinning inward hypertrophic remodeling in the microvasculature.

Topics: Alkynes; Animals; Arterioles; Cells, Cultured; Collagen; Collagenases; Cystathionine gamma-Lyase; Diet, High-Fat; Disease Models, Animal; Elastin; Enzyme Inhibitors; Fibronectins; Gene Expression Regulation; Glycine; Hydrogen Sulfide; Hypertrophy; Male; Mesentery; Mice, Inbred C57BL; Morpholines; Obesity; Organothiophosphorus Compounds; Signal Transduction; Vascular Remodeling; Vascular Stiffness

Loss of integrity and massive disruption of elastic fibers are key features of abdominal aortic aneurysm (AAA). Peroxisome proliferator-activated receptor γ (PPARγ) has been shown to attenuate AAA through inhibition of inflammation and proteolytic degradation. However, its involvement in elastogenesis during AAA remains unclear. PPARγ was highly expressed in human AAA within all vascular cells, including inflammatory cells and fibroblasts. In the aortas of transgenic mice expressing PPARγ at 25% normal levels (Pparg(C) (/-) mice), we observed the fragmentation of elastic fibers and reduced expression of vital elastic fiber components of elastin and fibulin-5. These were not observed in mice with 50% normal PPARγ expression (Pparg(+/-) mice). Infusion of a moderate dose of angiotensin II (500 ng/kg per minute) did not induce AAA but Pparg(+/-) aorta developed flattened elastic lamellae, whereas Pparg(C/-) aorta showed severe destruction of elastic fibers. After infusion of angiotensin II at 1000 ng/kg per minute, 73% of Pparg(C/-) mice developed atypical suprarenal aortic aneurysms: superior mesenteric arteries were dilated with extensive collagen deposition in adventitia and infiltrations of inflammatory cells. Although matrix metalloproteinase inhibition by doxycycline somewhat attenuated the dilation of aneurysm, it did not reduce the incidence nor elastic lamella deterioration in angiotensin II-infused Pparg(C/-) mice. Furthermore, PPARγ antagonism downregulated elastin and fibulin-5 in fibroblasts, but not in vascular smooth muscle cells. Chromatin immunoprecipitation assay demonstrated PPARγ binding in the genomic sequence of fibulin-5 in fibroblasts. Our results underscore the importance of PPARγ in AAA development though orchestrating proper elastogenesis and preserving elastic fiber integrity.

Topics: Analysis of Variance; Angiotensin II; Animals; Aorta, Abdominal; Aortic Aneurysm, Abdominal; Cells, Cultured; Disease Models, Animal; Elastin; Gene Expression Regulation; Humans; Inflammation; Male; Matrix Metalloproteinases; Mice; Mice, Knockout; Middle Aged; Muscle, Smooth, Vascular; PPAR gamma

Pelvic floor dysfunction (PFD) is a group of clinical conditions including stress urinary incontinence (SUI) and pelvic organ prolapse (POP). The abnormality of collagen and elastin metabolism in pelvic connective tissues is implicated in SUI and POP.. To reconstitute the connective tissues with normal distribution of collagen and elastin, we transduced elastin to bone marrow-derived mesenchymal stem cells (BMSC). Elastin-expressing BMSCs were then differentiated to fibroblasts using bFGF, which produced collagen and elastin. To achieve the sustained release of bFGF, we formulated bFGF in poly (lactic-co-glycolic acid) (PLGA) nanoparticles (NP).. In an in vitro cell culture system of 7 days, when no additional bFGF was administrated, the initial PLGA-loaded bFGF NP induced prolonged production of collagen and elastin from elastin-expressing BMSCs. In vivo, co-injection of PLGA-loaded bFGF NP and elastin-expressing BMSCs into the PFD rats significantly improved the outcome of urodynamic tests. Together, these results provided an efficient model of connective tissue engineering using BMSC and injectable PLGA-loaded growth factors.. Our results provided the first instance of a multidisciplinary approach, combining both stem cell and nanoparticle technologies, for the treatment of PFD.

Topics: Animals; Bone Marrow Cells; Cell Differentiation; Collagen; Disease Models, Animal; Drug Compounding; Elastin; Female; Fibroblast Growth Factor 2; Fibroblasts; Gene Expression; Lactic Acid; Mesenchymal Stem Cell Transplantation; Mesenchymal Stem Cells; Nanoparticles; Pelvic Organ Prolapse; Polyglycolic Acid; Polylactic Acid-Polyglycolic Acid Copolymer; Rats; Rats, Sprague-Dawley; Transduction, Genetic; Urinary Incontinence

High blood pressure and reduced aortic compliance are associated with increased atherosclerotic plaque accumulation in humans. Animal studies support these associations, but additional factors, such as fragmented elastic fibers, are present in most previous animal studies. Elastin heterozygous (Eln+/-) mice have high blood pressure and reduced aortic compliance, with no evidence of elastic fiber fragmentation and represent an appropriate model to directly investigate the effects of these factors on atherosclerosis.. Eln+/- and Eln+/+ mice were crossed with low density lipoprotein receptor knockout (Ldlr-/-) and wild-type (Ldlr+/+) mice and fed normal or Western diet (WD) for 16 weeks. We hypothesized that on WD, Eln+/-Ldlr-/- mice with high blood pressure and reduced aortic compliance would have increased atherosclerotic plaque accumulation compared to Eln+/+Ldlr-/- mice. We measured serum cholesterol and cytokine levels, blood pressure, aortic compliance, and plaque accumulation. Contrary to our hypothesis, we found that on WD, Eln+/-Ldlr-/- mice do not have increased plaque accumulation compared to Eln+/+Ldlr-/- mice. At the aortic root, there are no significant differences in plaque area between Eln+/-Ldlr-/- and Eln+/+Ldlr-/- mice on WD (p = 0.89), while in the ascending aorta, Eln+/-Ldlr-/- mice on WD have 29% less normalized plaque area than Eln+/+Ldlr-/- mice on WD (p = 0.009).. Using an atherogenic mouse model, we conclude that increased blood pressure and reduced aortic compliance are not direct causes of increased aortic plaque accumulation. We propose that additional insults, such as fragmentation of elastic fibers, are necessary to alter plaque accumulation.

Topics: Animals; Aorta; Aortic Diseases; Atherosclerosis; Blood Pressure; Cholesterol; Cytokines; Disease Models, Animal; Elastin; Female; Genotype; Heterozygote; Hypertension; Male; Mice; Mice, Knockout; Plaque, Atherosclerotic; Receptors, LDL; Stress, Mechanical

A medical treatment for urethral stricture (US) is not yet available.. To evaluate if local injection of human adipose tissue-derived stem cells (hADSC) prevents urethral fibrosis in a rat model of US.. Male rats were divided into three groups: sham, US, and hADSC (n=12 each). Sham rats received a vehicle injection in the urethral wall. US and hADSCs were incised and injected with the fibrosis-inducer transforming growth factor-β1 in the urethral wall.. One day later, hADSCs were injected in the urethral wall of hADSC rats whereas sham and US rats were injected with the vehicle. After 4 wk, the rats underwent cystometries and tissues were then harvested for functional and molecular analyses.. Cystometry, microultrasound, histochemistry, organ bath studies, reverse transcription polymerase chain reaction, and western blot.. US rats exhibited 49-51% shorter micturition intervals, 35-51% smaller micturition volumes and bladder capacity, 33-62% higher threshold pressures and flow pressures, and 35-37% lower bladder filling compliance compared with hADSC-treated rats and sham rats (p<0.05). By ultrasound, US rats had hyperechogenic and thick urethral walls with narrowed lumen compared with sham rats, whereas hADSC rats displayed less extensive urethral changes. Isolated detrusor from US rats exhibited 34-55% smaller contractions than detrusor from sham rats (p<0.05). Corresponding values were 11-35% for isolated detrusors from hADSC rats. Collagen and elastin protein expression were increased in the penile urethras of US rats compared with sham and hADSC groups (p<0.05). Endothelial and inducible nitric oxide synthase expressions were higher (p<0.05) in the hADSC group. Compared with US rats, hADSC rats demonstrated decreased expression of several fibrosis-related genes. Administration of hADSCs was performed at an early stage of US development, which we consider a limitation of the study.. Local injection of hADSCs prevents stricture formation and urodynamic complications in a new rat model for US.. Stem cell therapy is effective for preventing urethral stricture in an experimental setting.

Topics: Adipose Tissue; Animals; Blotting, Western; Collagen; Disease Models, Animal; Elastin; Fibrosis; Humans; Male; Nitric Oxide Synthase Type II; Nitric Oxide Synthase Type III; Rats; Rats, Sprague-Dawley; Reverse Transcriptase Polymerase Chain Reaction; Stem Cell Transplantation; Transforming Growth Factor beta1; Urethra; Urethral Stricture; Urination; Urodynamics

To study the role of lipocalin-2 (Lcn2) and the effect of Lcn2 blockade via anti-Lcn2 antibody in the development of abdominal aortic aneurysm (AAA).. Expression mRNA and protein levels of Lcn2 and its human orthologue neutrophil gelatinase-associated lipocalin (NGAL) in aortic wall samples from experimental mouse and human AAA samples, respectively, were analysed by real-time PCR and immunohistochemistry. Experimental AAA was induced by aortic elastase perfusion in wild-type mice (WT) and Lcn2-deficient mice (Lcn2-/-). NGAL/Lcn2 mRNA and protein levels in human and murine AAA samples were increased compared with healthy aortas. Decreased AAA incidence and reduced aortic expansion were observed in Lcn2-/- mice or mice preoperative treated with a polyclonal anti-Lcn2 antibody compared with WT mice or mice treated with control IgG, respectively, at Day 14 after elastase perfusion. Moreover, immunohistochemical analysis of AAA tissues from Lcn2-/- or anti-Lcn2-treated mice showed diminished elastin damage, reduced microvessels and polymorphonuclear neutrophil (PMN) infiltration, and enhanced preservation of vascular smooth muscle cells compared with WT aortas. Fluorescent molecular tomography revealed decreased MMP activity in AAA of Lcn2-/- mice compared with WT controls. Therapeutic administration of anti-Lcn2 antibody to WT mice 3 days after elastase perfusion decreased aortic dilatation and PMN infiltration compared with WT mice treated with control IgG.. Either Lcn2 deficiency or anti-Lcn2 antibody blockade limits AAA expansion in mice by decreasing PMN infiltration in the aorta. Lcn2 modulation may therefore be a viable new therapeutic option for the treatment of AAA.

Topics: Animals; Antibodies; Aorta, Abdominal; Aortic Aneurysm, Abdominal; Case-Control Studies; Cells, Cultured; Chemotaxis, Leukocyte; Dilatation, Pathologic; Disease Models, Animal; Elastin; Genetic Predisposition to Disease; Humans; Lipocalin-2; Matrix Metalloproteinases; Mice, Inbred C57BL; Mice, Knockout; Microvessels; Muscle, Smooth, Vascular; Neutrophil Infiltration; Phenotype; RNA, Messenger; Time Factors

Statins are prescribed for their preventative effects within atherosclerosis development. To our knowledge, no study focusing on very low-dose (non-hypolipidemic effect) and long-term atorvastatin treatment in vivo was available. Our aim was to assess the effect of such atorvastatin treatment on the mechanical and functional characteristics of arteries in the context of primary prevention.. An atorvastatin treatment (2.5 mg/kg/day) was tested against controls on 34 male 3 to 12 month-old WHHL rabbits. No effect on total cholesterol, triglycerides, HDL or LDL was observed. The arterial stiffness was evaluated on vigil animals by pulse wave velocity (PWV) measurement. Then, in vitro measurements were made to evaluate (1) the endothelial and vascular smooth muscle function, (2) the elasticity of the arterial wall and (3) the composition in collagen and elastin in the aorta.. The PWV increasing observed with age in control group was canceled by treatment, creating a significance difference between groups at 12 months (5.17 ± 0.50 vs 2.14 ± 0.34 m s(-1) in control and treated groups respectively). Vasoreactivity modifications can't explain this result but maintain of elasticity with treatment in large arteries was confirm by a static tensile test. A first possible explanation is the change of wall composition with treatment, validated by the percentage of elastin at 12 months, 4.4% lower in the control group compared to the treated group (p < 0.05).. This study shows that a non-hypocholesterolemic statin treatment could improve vessel elasticity in the atherosclerotic WHHL model. The great novelty of this work is the vessel wall composition changing associated. This first approach in animal opens the reflection on the use of these low doses in humans. This could be interesting in the context of arterial stiffening with aging, non-hyperlipidemic atherosclerosis or with cholesterol reduce by another therapy or lifestyle modification.

Topics: Aging; Animals; Aorta; Arteries; Atherosclerosis; Atorvastatin; Blood Pressure; Collagen; Disease Models, Animal; Elastic Modulus; Elastin; Heart Rate; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Male; Pulse Wave Analysis; Rabbits; Stress, Mechanical; Tensile Strength

Marfan syndrome (MFS) is a connective tissue disorder caused by mutations in the fibrillin-1 gene. Patients with MFS are at risk of aortic aneurysm formation and dissection. Usually, blood pressure-lowering drugs are used to reduce aortic events; however, this is not sufficient for most patients. In the aorta of smooth muscle cell-specific sirtuin-1-deficient mice, spontaneous aneurysm formation and senescence are observed. Resveratrol is known to enhance sirtuin-1 activity and to reduce senescence, which prompted us to investigate the effectiveness of resveratrol in inhibition of aortic dilatation in the Fbn1(C1039G/+) MFS mouse model.. Aortic senescence strongly correlates with aortic root dilatation rate in MFS mice. However, although resveratrol inhibits aortic dilatation, it only shows a trend toward reduced aortic senescence. Resveratrol enhances nuclear localization of sirtuin-1 in the vessel wall and, in contrast to losartan, does not affect leukocyte infiltration nor activation of SMAD2 and extracellular signal-regulated kinases 1/2 (ERK1/2). Interestingly, specific sirtuin-1 activation (SRT1720) or inhibition (sirtinol) in MFS mice does not affect aortic root dilatation rate, although senescence is changed. Resveratrol reduces aortic elastin breaks and decreases micro-RNA-29b expression coinciding with enhanced antiapoptotic Bcl-2 expression and decreased number of terminal apoptotic cells. In cultured smooth muscle cells, the resveratrol effect on micro-RNA-29b downregulation is endothelial cell and nuclear factor κB-dependent.. Resveratrol inhibits aortic root dilatation in MFS mice by promoting elastin integrity and smooth muscle cell survival, involving downregulation of the aneurysm-related micro-RNA-29b in the aorta. On the basis of these data, resveratrol holds promise as a novel intervention strategy for patients with MFS.

Topics: Active Transport, Cell Nucleus; Animals; Aorta; Aortic Aneurysm; Apoptosis; Cells, Cultured; Cellular Senescence; Dilatation, Pathologic; Disease Models, Animal; Elastin; Female; Fibrillin-1; Genetic Predisposition to Disease; Human Umbilical Vein Endothelial Cells; Humans; Male; Marfan Syndrome; Mice, Inbred C57BL; Mice, Mutant Strains; MicroRNAs; Muscle, Smooth, Vascular; Myocytes, Smooth Muscle; Phenotype; Proto-Oncogene Proteins c-bcl-2; Resveratrol; Sirtuin 1; Stilbenes

Brachytherapy is a targeted type of radiotherapy utilized in the treatment of cancers. Elastin-like polypeptides are a unique class of genetically engineered peptide polymers that have several attractive properties for brachytherapy.. To explore the feasibility and application of brachytherapy for VX2 liver tumor using elastin-like polypeptides with (131)I so as to provide reliable experimental evidence for a new promising treatment of liver cancer.. Elastin-like polypeptide as carrier was labeled with (131)I using the iodogen method. Ten eligible rabbits with VX2 liver tumor were randomly divided into the treatment group (n = 5) and control group (n = 5). The treatment group received brachytherapy using elastin-like polypeptide with (131)I, and in the control group, elastin-like polypeptide was injected into the VX2 liver tumor as a control. Periodic biochemical and imaging surveillances were required to assess treatment efficacy.. The stability of elastin-like polypeptide with (131)I in vitro was maintained at over 96.8 % for 96 h. Biochemistry and imaging indicated brachytherapy using elastin-like polypeptide with (131)I for liver tumor can improve liver function and inhibit tumor growth (P < 0.05).. Elastin-like polypeptide can be an ideal carrier of (131)I and have high labeling efficiency, radiochemical purity and stability. Brachytherapy using elastin-like polypeptide with (131)I for liver tumor is a useful therapy that possesses high antitumor efficacy advantages.

Topics: Animals; Brachytherapy; Disease Models, Animal; Elastin; Feasibility Studies; Iodine Radioisotopes; Liver Neoplasms, Experimental; Male; Neoplasm Transplantation; Peptides; Rabbits; Single Photon Emission Computed Tomography Computed Tomography

The aim of this study was to develop and validate a model for pulmonary fibrosis, using ex vivo tissue cultures of lungs from bleomycin treated animals, enabling the investigation of fibrosis remodeling using novel biomarkers for the detection of ECM protein fragments. The combination of in vivo and ex vivo models together with ECM remodeling markers may provide a translational tool for screening of potential treatments for IPF.. Twenty female Sprague-Dawley rats, twelve weeks of age, were administrated either two doses of bleomycin (BLM) (n = 14) or saline (n = 6) I.T., two days apart. Ten rats were euthanized at day seven and the remaining ten rats at day fourteen, after the last dose. Precision-cut lung slices (PCLS) were made and cultured for 48 h. Ten female Sprague-Dawley rats, twelve weeks of age, were administrated either two doses of BLM (n = 7) or saline (n = 3) I.T., two days apart. The rats were euthanized fourteen days after the last dose. PCLS were made and cultured for 48 h in: medium, medium + 100 μM IBMX (PDE inhibitor), or medium + 10 μM GM6001 (MMP inhibitor). Turnover of type I collagen (P1NP, C1M), type III collagen (iP3NP, C3M) and elastin degradation (ELM7) was measured in the supernatant of the cultured PCLS.. P1NP, C1M, iP3NP, C3M and ELM7 were significantly increased in supernatants from BLM animals (P ≤ 0.05 - P ≤ 0.0001) when compared to controls. P1NP, C1M, iP3NP, C3M and ELM7 were significantly increased in supernatants from day seven BLM animals compared to day fourteen BLM animals (P ≤ 0.05 - P ≤ 0.0001). P1NP, C1M, iP3NP, C3M and ELM7 were significantly decreased when adding IBMX to the culture medium of fibrotic lung tissue (P ≤ 0.05 - P ≤ 0.0001). C1M, C3M and ELM7 were significantly decreased when adding GM6001 to the culture medium (P ≤ 0.05 - P ≤ 0.0001). Sirius Red and Orcein staining confirmed the presence of collagen and elastin deposition in the lungs of the animals receiving BLM.. The protein fingerprint technology allows the assessment of ECM remodeling markers in the BLM PCLS model. By combining in vivo, ex vivo models and the protein fingerprint technology in the fibrotic phase of the model, we believe the chance of translation from animal model to human is markedly increased.

Topics: 1-Methyl-3-isobutylxanthine; Airway Remodeling; Animals; Bleomycin; Collagen Type I; Collagen Type III; Disease Models, Animal; Elastin; Female; Idiopathic Pulmonary Fibrosis; Lung; Peptide Fragments; Phosphodiesterase Inhibitors; Procollagen; Proteolysis; Rats, Sprague-Dawley; Time Factors; Tissue Culture Techniques

Degeneration of elastin plays a vital role in the pathology and progression of abdominal aortic aneurysm (AAA). Our previous study showed that pentagalloyl glucose (PGG), a core derivative of tannic acid, hinders the development of AAAs in a clinically relevant animal model when applied locally. In this study, we tested whether targeted nanoparticles (NPs) can deliver PGG to the site of an aneurysm and prevent aneurysmal growth by protecting elastin. PGG-loaded albumin NPs with a surface-conjugated elastin-specific antibody were prepared. Aneurysms were induced by calcium chloride-mediated injury to the abdominal aorta in rats. NPs were injected into the tail vein after 10 days of CaCl

Topics: Animals; Antibodies; Aorta, Abdominal; Aortic Aneurysm, Abdominal; Calcium Chloride; Cells, Cultured; Cytoprotection; Disease Models, Animal; Drug Compounding; Drug Liberation; Elastic Tissue; Elastin; Hydrolyzable Tannins; Injections, Intravenous; Macrophages; Male; Matrix Metalloproteinases; Nanoparticles; Particle Size; Proteolysis; Rats, Sprague-Dawley; Solubility; Vascular Calcification

To investigate the 3-dimensional (3D) cell and extracellular matrix (ECM) structure of mouse peripheral corneas in normal and corneal neovascularization tissues using 2-photon microscopy (TPM) based on both intrinsic and extrinsic moxifloxacin contrasts.. Peripheral corneas in freshly enucleated mouse eyes were imaged by TPM based on both intrinsic and extrinsic contrasts. Intrinsic autofluorescence and second harmonic generation were used to image cells and ECM collagen, respectively. Moxifloxacin ophthalmic solution was applied to image cells. The peripheral cornea, limbus, and sclera were imaged in 3D. In addition to normal mice, mouse models of suture-induced corneal neovascularization were imaged to visualize changes in the microstructure.. Complex 3D cell and ECM structures in the cornea, limbus, and sclera were visualized by TPM. TPM images based on intrinsic contrasts visualized both cell and ECM structures, and TPM images based on moxifloxacin visualized cell structures with enhanced contrast. On the limbus side of the mouse peripheral cornea, TPM images visualized the vasculature in the limbus, the trabecular meshwork/Schlemm canal, iris, and ciliary body. On the scleral side, TPM images visualized cell and ECM structures in the sclera and multiple cell layers below the sclera. TPM images of the peripheral cornea in the corneal neovascularization condition visualized the extension of vasculature from the limbus to the cornea.. TPM imaging based on both intrinsic and external moxifloxacin contrasts visualized detailed 3D cell and ECM microstructures in the mouse peripheral cornea. TPM based on moxifloxacin might be advantageous for studying cell structures by enhancing image contrast.

Topics: Animals; Collagen; Contrast Media; Cornea; Corneal Neovascularization; Disease Models, Animal; Elastin; Extracellular Matrix; Female; Fluoroquinolones; Imaging, Three-Dimensional; Limbus Corneae; Mice; Mice, Inbred BALB C; Microscopy, Fluorescence, Multiphoton; Moxifloxacin; Sclera

The purpose of this study was to evaluate the diameter and thickness-related variations in mechanical properties of degraded arterial wall. To this end, ring tests were performed on 31 samples from the rat xenograft model of abdominal aortic aneurysm (AAA) and failure properties were determined. An inverse finite element method was then employed to identify the material parameters of a hyperelastic and incompressible strain energy function. Correlations with outer diameter and wall thickness of the rings were examined. Furthermore, we investigated the changes in mechanical properties between the grafts, which consist in guinea pig decellularized aortas, native murine aortas and degraded aortas (AAAs). Decellularized aortas presented a significantly lower ultimate strain associated with a higher stiffening rate compared to native aortas. AAAs exhibited a significantly lower ultimate stress than other groups and an extensible-but-stiff behavior. The proposed approach revealed correlations of ultimate stress and material parameters of aneurysmal aortas with outer diameter and thickness. In particular, the negative correlations of the material parameter accounting for the response of the non-collagenous matrix with diameter and thickness (r=-0.67 and r=-0.73, p<0.001) captured the gradual loss of elastin with dilatation observed in histology (r=-0.97, p<0.001). Moreover, it exposed the progressive weakening of the wall with enlargement and thickening (r=-0.64 and r=-0.69, p<0.001), suggesting that wall thickness and diameter may be indicators of rupture risk in the rat xenograft model.

Topics: Animals; Aorta, Abdominal; Aortic Aneurysm, Abdominal; Biomechanical Phenomena; Disease Models, Animal; Elastin; Finite Element Analysis; Guinea Pigs; Heterografts; Male; Models, Biological; Rats; Rats, Inbred F344

Aneurysm-osteoarthritis syndrome characterized by unpredictable aortic aneurysm formation, is caused by SMAD3 mutations. SMAD3 is part of the SMAD2/3/4 transcription factor, essential for TGF-β-activated transcription. Although TGF-β-related gene mutations result in aneurysms, the underlying mechanism is unknown. Here, we examined aneurysm formation and progression in Smad3

Topics: Aneurysm; Animals; Aortic Aneurysm; Cell Proliferation; Connective Tissue; Disease Models, Animal; Echocardiography; Elastin; Extracellular Signal-Regulated MAP Kinases; Female; Immunohistochemistry; Inflammation; Male; Matrix Metalloproteinases; Mice; Mice, Knockout; Models, Biological; Molecular Imaging; Mortality; Muscle, Smooth, Vascular; Signal Transduction; Smad2 Protein; Smad3 Protein; Transcriptional Activation; Transforming Growth Factor beta; X-Ray Microtomography

Pelvic floor dysfunction (PFD) is a condition affecting many women worldwide, with symptoms including stress urinary incontinence (SUI) and pelvic organ prolapse (POP). We have previously demonstrated stable elastin-expressing bone marrow-derived mesenchymal stem cells (BMSCs) attenuated PFD in rats, and aim to further study the effect of microRNA-29a-3p regulation on elastin expression and efficacy of BMSC transplantation therapy.. We inhibited endogenous microRNA-29a-3p in BMSCs and investigated its effect on elastin expression by RT-PCR and Western blot. MicroRNA-29-inhibited BMSCs were then transplanted into PFD rats, accompanied by sustained release of bFGF using formulated bFGF in poly (lactic-co-glycolic acid) (PLGA) nanoparticles (NP), followed by evaluation of urodynamic tests.. MicroRNA-29a-3p inhibition resulted in upregulated expression and secretion of elastin in in vitro culture of BMSCs. After co-injection with PLGA-loaded bFGF NP into the PFD rats in vivo, microRNA-29a-3p-inhibited BMSCs significantly improved the urodynamic test results.. Our multidisciplinary study, combining microRNA biology, genetically engineered BMSCs, and nanoparticle technology, provides an excellent stem cell-based therapy for repairing connective tissues and treating PFD.

Topics: Animals; Bone Marrow; Bone Marrow Cells; Cells, Cultured; Disease Models, Animal; Elastin; Fibroblast Growth Factors; Humans; Lactic Acid; Mesenchymal Stem Cell Transplantation; Mesenchymal Stem Cells; MicroRNAs; Nanoparticles; Pelvic Floor; Pelvic Floor Disorders; Polyglycolic Acid; Polylactic Acid-Polyglycolic Acid Copolymer; Rats

Elastin-like polypeptide (ELP)-based drug delivery has been utilized for various applications including cancer therapies for many years. Genetic incorporation of internalization ligands and cell-targeting peptides along with ELP polymer enhanced tumor accumulation and retention time as well as stability and activities of the drug conjugates. Herein, we described a unique delivery system comprised of genetically engineered ELP incorporated with multiple copies of IL-4 receptor targeting peptide (AP1) periodically and proapoptotic peptide (KLAKLAK)

Topics: Animals; Antimicrobial Cationic Peptides; Antineoplastic Agents; Cell Line, Tumor; Cell Survival; Disease Models, Animal; Drug Carriers; Elastin; Female; Heterografts; Humans; Mice, Inbred BALB C; Mice, Inbred C57BL; Nanoparticles; Neoplasms; Peptides; Protein Multimerization; Treatment Outcome

There is a need for animal models of plaque rupture. We previously reported that elastin fragmentation, due to a mutation (C1039G(+/-)) in the fibrillin-1 (Fbn1) gene, promotes atherogenesis and a highly unstable plaque phenotype in apolipoprotein E deficient (ApoE(-/-)) mice on a Western-type diet (WD). Here, we investigated whether plaque rupture occurred in ApoE(-/-)Fbn1(C1039G+/-) mice and was associated with myocardial infarction, stroke, and sudden death.. Female ApoE(-/-)Fbn1(C1039G+/-) and ApoE(-/-) mice were fed a WD for up to 35 weeks. Compared to ApoE(-/-) mice, plaques of ApoE(-/-)Fbn1(C1039G+/-) mice showed a threefold increase in necrotic core size, augmented T-cell infiltration, a decreased collagen I content (70 ± 10%), extensive neovascularization, intraplaque haemorrhage, and a significant increase in matrix metalloproteinase-2, -9, -12, and -13 expression or activity. Plaque rupture was observed in 70% of ascending aortas and in 50% of brachiocephalic arteries of ApoE(-/-)Fbn1(C1039G+/-) mice. In ApoE(-/-) mice, plaque rupture was not seen in ascending aortas and only in 10% of brachiocephalic arteries. Seventy percent of ApoE(-/-)Fbn1(C1039G+/-) mice died suddenly, whereas all ApoE(-/-) mice survived. ApoE(-/-)Fbn1(C1039G+/-) mice showed coronary plaques and myocardial infarction (75% of mice). Furthermore, they displayed head tilt, disorientation, and motor disturbances (66% of cases), disturbed cerebral blood flow (73% of cases; MR angiograms) and brain hypoxia (64% of cases), indicative of stroke.. Elastin fragmentation plays a key role in plaque destabilization and rupture. ApoE(-/-)Fbn1(C1039G+/-) mice represent a unique model of acute plaque rupture with human-like complications.

Topics: Animals; Aorta; Apolipoproteins E; Biomarkers; Brachiocephalic Trunk; Cardiomegaly; Carotid Artery, Common; Cerebrovascular Circulation; Death, Sudden; Diet, Western; Disease Models, Animal; Elastin; Female; Fibrillin-1; Fibrillins; Hemorrhage; Hypoxia, Brain; Mice; Microfilament Proteins; Microvessels; Myocardial Infarction; Neovascularization, Pathologic; Nervous System Diseases; Plaque, Atherosclerotic; Rupture, Spontaneous; Stroke; Ventricular Dysfunction, Left

Preterm infants are at high risk for long-term abnormalities in cardiopulmonary function. Our objectives were to determine the long-term effects of hypoxia or hyperoxia on cardiopulmonary development and function in an immature animal model. Newborn C57BL/6 mice were exposed to air, hypoxia (12% oxygen), or hyperoxia (85% oxygen) from Postnatal Day 2-14, and then returned to air for 10 weeks (n = 2 litters per condition; > 10/group). Echocardiography, blood pressure, lung function, and lung development were evaluated at 12-14 weeks of age. Lungs from hyperoxia- or hypoxia-exposed mice were larger and more compliant (compliance: air, 0.034 ± 0.001 ml/cm H2O; hypoxia, 0.049 ± 0.002 ml/cm H2O; hyperoxia, 0.053 ± 0.002 ml/cm H2O; P < 0.001 air versus others). Increased airway reactivity, reduced bronchial M2 receptor staining, and increased bronchial α-smooth muscle actin content were noted in hyperoxia-exposed mice (maximal total lung resistance with methacholine: air, 1.89 ± 0.17 cm H2O ⋅ s/ml; hypoxia, 1.52 ± 0.34 cm H2O ⋅ s/ml; hyperoxia, 4.19 ± 0.77 cm H2O ⋅ s/ml; P < 0.004 air versus hyperoxia). Hyperoxia- or hypoxia-exposed mice had larger and fewer alveoli (mean linear intercept: air, 40.2 ± 0. 0.8 μm; hypoxia, 76.4 ± 2.4 μm; hyperoxia, 95.6 ± 4.6 μm; P < 0.001 air versus others; radial alveolar count [n]: air, 11.1 ± 0.4; hypoxia, 5.7 ± 0.3; hyperoxia, 5.6 ± 0.3; P < 0.001 air versus others). Hyperoxia-exposed adult mice had left ventricular dysfunction without systemic hypertension. In conclusion, exposure of newborn mice to hyperoxia or hypoxia leads to cardiopulmonary abnormalities in adult life, similar to that described in ex-preterm infants. This animal model may help to identify underlying mechanisms and to develop therapeutic strategies for pulmonary morbidity in former preterm infants.

Topics: Actins; Age Factors; Animals; Animals, Newborn; Blood Pressure; Bronchial Hyperreactivity; Bronchoconstriction; Cardiovascular System; Collagen; Disease Models, Animal; Elastin; Hyperoxia; Hypoxia; Lung; Lung Compliance; Mice, Inbred C57BL; Receptor, Muscarinic M2; Time Factors; Ventricular Dysfunction, Left; Ventricular Function, Left

Rupture and dissection of aortic root aneurysms remain the leading causes of death in patients with the Marfan syndrome, a hereditary connective tissue disorder that affects 1 in 5000 individuals worldwide. In the present study, we use a Marfan mouse model (Fbn1(C1039G/+)) to investigate the biological importance of apoptosis during aneurysm development in Marfan syndrome.. Using in vivo single-photon emission computed tomographic-imaging and ex vivo autoradiography for Tc99m-annexin, we discovered increased apoptosis in the Fbn1(C1039G/+) ascending aorta during early aneurysm development peaking at 4 weeks. Immunofluorescence colocalization studies identified smooth muscle cells (SMCs) as the apoptotic cell population. As biological proof of concept that early aortic wall apoptosis plays a role in aneurysm development in Marfan syndrome, Fbn1(C1039G/+) mice were treated daily from 2 to 6 weeks with either (1) a pan-caspase inhibitor, Q-VD-OPh (20 mg/kg), or (2) vehicle control intraperitoneally. Q-VD-OPh treatment led to a significant reduction in aneurysm size and decreased extracellular matrix degradation in the aortic wall compared with control mice. In vitro studies using Fbn1(C1039G/+) ascending SMCs showed that apoptotic SMCs have increased elastolytic potential compared with viable cells, mostly because of caspase activity. Moreover, in vitro (1) cell membrane isolation, (2) immunofluorescence staining, and (3) scanning electron microscopy studies illustrate that caspases are expressed on the exterior cell surface of apoptotic SMCs.. Caspase inhibition attenuates aneurysm development in an Fbn1(C1039G/+) Marfan mouse model. Mechanistically, during apoptosis, caspases are expressed on the cell surface of SMCs and likely contribute to elastin degradation and aneurysm development in Marfan syndrome.

Topics: Animals; Aorta; Aortic Aneurysm; Apoptosis; Autoradiography; Caspase Inhibitors; Caspases; Cell Membrane; Cells, Cultured; Disease Models, Animal; Disease Progression; Elastin; Female; Fibrillin-1; Fibrillins; Fluorescent Antibody Technique; Male; Marfan Syndrome; Mice, Inbred C57BL; Mice, Mutant Strains; Microfilament Proteins; Microscopy, Electron, Scanning; Muscle, Smooth, Vascular; Mutation; Myocytes, Smooth Muscle; Time Factors; Tomography, Emission-Computed, Single-Photon; Vascular Remodeling

Low-density lipoprotein receptor-related protein 1 (LRP1), a multifunctional protein involved in endocytosis and cell signaling pathways, leads to several vascular pathologies when deleted in vascular smooth muscle cells (SMCs). The purpose of this study was to determine whether LRP1 deletion in SMCs influenced angiotensin II-induced arterial pathologies.. LRP1 protein abundance was equivalent in selected arterial regions, but SMC-specific LRP1 depletion had no effect on abdominal and ascending aortic diameters in young mice. To determine the effects of LRP1 deficiency on angiotensin II vascular responses, SMC-specific LRP1 (smLRP1(+/+)) and smLRP1-deficient (smLRP1(-/-)) mice were infused with saline, angiotensin II, or norepinephrine. Several smLRP(-/-) mice died of superior mesenteric arterial (SMA) rupture during angiotensin II infusion. In surviving mice, angiotensin II profoundly augmented SMA dilation in smLRP1(-/-) mice. SMA dilation was blood pressure dependent as demonstrated by a similar response during norepinephrine infusion. SMA dilation was also associated with profound macrophage accumulation, but minimal elastin fragmentation. Angiotensin II infusion led to no significant differences in abdominal aorta diameters between smLRP1(+/+) and smLRP1(-/-) mice. In contrast, ascending aortic dilation was exacerbated markedly in angiotensin II-infused smLRP1(-/-) mice, but norepinephrine had no significant effect on either aortic region. Ascending aortas of smLRP1(-/-) mice infused with angiotensin II had minimal macrophage accumulation but significantly increased elastin fragmentation and mRNA abundance of several LRP1 ligands including MMP-2 (matrix metalloproteinase-2) and uPA (urokinase plasminogen activator).. smLRP1 deficiency had no effect on angiotensin II-induced abdominal aortic aneurysm formation. Conversely, angiotensin II infusion in smLRP1(-/-) mice exacerbated SMA and ascending aorta dilation. Dilation in these 2 regions had differential association with blood pressure and divergent pathological characteristics.

Topics: Aneurysm; Angiotensin II; Animals; Aorta, Abdominal; Aortic Aneurysm; Aortic Aneurysm, Abdominal; Arterial Pressure; Cells, Cultured; Dilatation, Pathologic; Disease Models, Animal; Elastin; Gene Deletion; Ligands; Low Density Lipoprotein Receptor-Related Protein-1; Macrophages; Male; Matrix Metalloproteinase 2; Mesenteric Artery, Superior; Mice, Knockout; Muscle, Smooth, Vascular; Myocytes, Smooth Muscle; Norepinephrine; Receptors, LDL; RNA, Messenger; Tumor Suppressor Proteins; Urokinase-Type Plasminogen Activator

Two-day infusion of angiotensin II to apolipoprotein E-deficient (ApoE(-/-)) mice provides a model of pre-abdominal aortic aneurysm. Long chain omega-3 polyunsaturated fatty acids (n-3 PUFAs) have anti-inflammatory effects. This study examined the effect of an eight-week low or high n-3 PUFA diet in ApoE(-/-) mice on matrix metalloproteinase (MMP) expression and elastin degradation.. ApoE(-/-) mice were fed a low or high n-3 PUFA diet for eight weeks prior to two-day infusion with angiotensin II. The omega-3 index, MMP-2, MMP-9, TIMP-1, and TGF-β1 immunoreactivity, and elastin fragmentation were measured.. The omega-3 index with the low and high n-3 PUFA diet was 3.78% and 13.03%, respectively. MMP-9 immunoreactive stain intensity was lower in mice fed the high, compared to the low n-3 PUFA diet in endothelial cells (suprarenal aorta), and inflammatory cells (suprarenal and infrarenal aorta). Inflammatory cells had higher TIMP-1 and TGF-β1 stain intensity in mice fed the high, compared to the low n-3 PUFA diet (suprarenal aorta). MMP-2 immunoreactivity was unaffected by diet. A non-significant trend for reduced elastin fragmentation was observed in mice fed the high n-3 PUFA diet.. Dietary supplementation with n-3 PUFAs may have protective anti-inflammatory effects mediated through modulation of MMPs and TIMPs.

Topics: Animals; Aortic Aneurysm, Abdominal; Apolipoproteins E; Dietary Supplements; Disease Models, Animal; Elastin; Fatty Acids, Omega-3; Gene Expression Regulation, Enzymologic; Matrix Metalloproteinase 2; Matrix Metalloproteinase 9; Mice; Mice, Knockout; Transforming Growth Factor beta1

Interaction of the activating sequence in thrombospondin-1 (TSP-1) with the conserved sequence (leucine-serine-lysine-leucine [LSKL]) in the latency-associated peptide region of latent transforming growth factor (TGF)-β complex is important in regulating TGF-β1 activity. We aimed to assess the effect of blocking peptide LSKL on the progression of pre-established abdominal aortic aneurysm in angiotensin II-infused apolipoprotein E-deficient (ApoE(-/-)) mice.. Abdominal aortic aneurysm was established in 3-month-old male ApoE(-/-) mice with subcutaneous infusion of angiotensin II for 28 days. After this, mice received LSKL peptide or control SLLK (serine-leucine-leucine-lysine) peptide (4 mg/kg) via daily intraperitoneal injection for an additional 2 weeks. Administration of LSKL peptide promoted larger suprarenal aortic diameter, as determined by ultrasound and morphometric analysis, and stimulated more severe atherosclerosis within the aortic arch. In addition, mice receiving LSKL peptide exhibited elevated circulating proinflammatory cytokine levels and greater inflammatory cells within the suprarenal aorta compared with controls. Mice receiving LSKL peptide showed low plasma TGF-β1 activity and low levels of aortic tissue phosphorylated to total Smad2/3. Aortic gene expression of TGF-β receptor 1 (TGFBRI) and receptor 2 (TGFBRII), but not TGF-β1 and thrombospondin-1, were lower in mice receiving LSKL peptide than controls. LSKL peptide administration was associated with greater aortic elastin fragmentation and lower expression and activity of the TGF-β1-target gene lysyl oxidase like 1 (LOXL1).. Attenuation of thrombospondin-1-directed activation of TGF-β1 promotes abdominal aortic aneurysm and atherosclerosis progression in the angiotensin II-infused ApoE(-/-) mouse model.

Topics: Amino Acid Oxidoreductases; Angiotensin II; Animals; Aorta; Aortic Aneurysm, Abdominal; Apolipoproteins E; Atherosclerosis; Cytokines; Disease Models, Animal; Disease Progression; Elastin; Inflammation Mediators; Injections, Intraperitoneal; Male; Mice, Knockout; Peptides; Phosphorylation; Protein Serine-Threonine Kinases; Receptor, Transforming Growth Factor-beta Type I; Receptor, Transforming Growth Factor-beta Type II; Receptors, Transforming Growth Factor beta; Smad2 Protein; Smad3 Protein; Thrombospondin 1; Time Factors; Transforming Growth Factor beta1

TMEM100 was previously identified as a downstream target of activin receptor-like kinase 1 (ALK1; ACVRL1) signalling. Mutations on ALK1 cause hereditary haemorrhagic telangiectasia (HHT), a vascular disorder characterized by mucocutaneous telangiectases and visceral arteriovenous malformations (AVMs). The aims of this study are to investigate the in vivo role of TMEM100 at various developmental and adult stages and to determine the extent to which TMEM100 contributed to the development of AVMs as a key downstream effector of ALK1.. Blood vasculature in Tmem100-null embryos and inducible Tmem100-null neonatal and adult mice was examined. We found that TMEM100 deficiency resulted in cardiovascular defects at embryonic stage; dilated vessels, hyperbranching, and increased number of filopodia in the retinal vasculature at neonatal stage; and various vascular abnormalities, including internal haemorrhage, arteriovenous shunts, and weakening of vasculature with abnormal elastin layers at adult stage. However, arteriovenous shunts in adult mutant mice appeared to be underdeveloped without typical tortuosity of vessels associated with AVMs. We uncovered that the expression of genes encoding cell adhesion and extracellular matrix proteins was significantly affected in lungs of adult mutant mice. Especially Mfap4, which is associated with elastin fibre formation, was mostly down-regulated.. These results demonstrate that TMEM100 has essential functions for the maintenance of vascular integrity as well as the formation of blood vessels. Our results also indicate that down-regulation of Tmem100 is not the central mechanism of HHT pathogenesis, but it may contribute to the development of vascular pathology of HHT by weakening vascular integrity.

Topics: Activin Receptors, Type I; Activin Receptors, Type II; Age Factors; Animals; Arteriovenous Malformations; Carrier Proteins; Disease Models, Animal; Elastin; Extracellular Matrix Proteins; Gene Expression Regulation, Developmental; Genotype; Gestational Age; Glycoproteins; Lung; Membrane Proteins; Mice, 129 Strain; Mice, Inbred C57BL; Mice, Knockout; Morphogenesis; Phenotype; Retinal Vessels; Signal Transduction; Telangiectasia, Hereditary Hemorrhagic

Increased large artery stiffness is a hallmark of arterial dysfunction with advancing age and is also present in other disease conditions such as diabetes. Increased large artery stiffness is correlated with resistance artery dysfunction in humans. Using a mouse model of altered arterial elastin content, this is the first study to examine the cause-and-effect relationship between large artery stiffness and peripheral resistance artery function. Our results indicate that mice with genetically greater large artery stiffness have impaired cerebral artery endothelial function, but generally preserved skeletal muscle feed artery endothelial function. The mechanisms for impaired cerebral artery endothelial function are reduced nitric oxide bioavailability and increased oxidative stress. These findings suggest that interventions that target large artery stiffness may be important to reduce disease risk associated with cerebral artery dysfunction in conditions such as advancing age.. Advancing age as well as diseases such as diabetes are characterized by both increased large artery stiffness and impaired peripheral artery function. It has been hypothesized that greater large artery stiffness causes peripheral artery dysfunction; however, a cause-and-effect relationship has not previously been established. We used elastin heterozygote mice (Eln(+/-) ) as a model of increased large artery stiffness without co-morbidities unrelated to the large artery properties. Aortic stiffness, measured by pulse wave velocity, was ∼35% greater in Eln(+/-) mice than in wild-type (Eln(+/+) ) mice (P = 0.04). Endothelium-dependent dilatation (EDD), assessed by the maximal dilatation to acetylcholine, was ∼40% lower in Eln(+/-) than Eln(+/+) mice in the middle cerebral artery (MCA, P < 0.001), but was similar between groups in the gastrocnemius feed arteries (GFA, P = 0.79). In the MCA, EDD did not differ between groups after incubation with the nitric oxide (NO) synthase inhibitor N(ω) -nitro-l-arginine methyl ester (P > 0.05), indicating that lower NO bioavailability contributed to the impaired EDD in Eln(+/-) mice. Superoxide production and content of the oxidative stress marker nitrotyrosine was higher in MCAs from Eln(+/-) compared with Eln(+/+) mice (P < 0.05). In the MCA, after incubation with the superoxide scavenger TEMPOL, maximal EDD improved by ∼65% in Eln(+/-) (P = 0.002), but was unchanged in Eln(+/+) mice (P = 0.17). These results indicate that greater large artery stiffness has a more profound effect on endothelial function in cerebral arteries compared with skeletal muscle feed arteries. Greater large artery stiffness can cause cerebral artery endothelial dysfunction by reducing NO bioavailability and increasing oxidative stress.

Topics: Animals; Cerebral Arteries; Disease Models, Animal; Elastin; Endothelium, Vascular; Enzyme Inhibitors; Indomethacin; Mice; Mice, Knockout; Muscle, Skeletal; NG-Nitroarginine Methyl Ester; Vascular Resistance; Vascular Stiffness; Vasodilation

Aortic aneurysm, focal dilation of the aorta, results from impaired integrity of aortic extracellular matrix (ECM). Matrix metalloproteinases (MMPs) are traditionally known as ECM-degrading enzymes. MMP2 has been associated with aneurysm in patients and in animal models. We investigated the role of MMP2 in thoracic aortic aneurysm using 2 models of aortic remodeling and aneurysm.. Male 10-week-old MMP2-deficient (MMP2(-/-)) and wild-type mice received angiotensin II (Ang II, 1.5 mg/kg/day) or saline (Alzet pump) for 4 weeks. Although both genotypes exhibited dilation of the ascending aorta after Ang II infusion, MMP2(-/-) mice showed more severe dilation of the thoracic aorta and thoracic aortic aneurysm. The Ang II-induced increase in elastin and collagen (mRNA and protein) was markedly suppressed in MMP2(-/-) thoracic aorta and smooth muscle cells, whereas only mRNA levels were reduced in MMP2(-/-)-Ang II abdominal aorta. Consistent with the absence of MMP2, proteolytic activities were lower in MMP2(-/-)-Ang II compared with wild-type-Ang II thoracic and abdominal aorta. MMP2-deficiency suppressed the activation of latent transforming growth factor-β and the Smad2/3 pathway in vivo and in vitro. Intriguingly, MMP2(-/-) mice were protected against CaCl2-induced thoracic aortic aneurysm, which triggered ECM degradation but not synthesis.. This study reveals the dual role of MMP2 in ECM degradation, as well as ECM synthesis. Moreover, the greater susceptibility of the thoracic aorta to impaired ECM synthesis, compared with vulnerability of the abdominal aorta to aberrant ECM degradation, provides an insight into the regional susceptibility of the aorta to aneurysm development.

Topics: Angiotensin II; Animals; Aorta, Thoracic; Aortic Aneurysm, Thoracic; Calcium Chloride; Cells, Cultured; Collagen; Dilatation, Pathologic; Disease Models, Animal; Elastin; Genotype; Male; Matrix Metalloproteinase 2; Mice, Inbred C57BL; Muscle, Smooth, Vascular; Myocytes, Smooth Muscle; Phenotype; RNA, Messenger; Signal Transduction; Smad2 Protein; Smad3 Protein; Transforming Growth Factor beta; Ultrasonography; Vascular Remodeling

Chronic exposure to ultraviolet (UV) radiation causes oxidative stress, which is involved in photoaging and actinic elastosis. UV and reactive oxygen species generate lipid peroxidation products, including the α, β-unsaturated carbonyl compounds such as acrolein or 4-hydroxynonenal (4-HNE). These aldehydes can modify proteins of the extracellular matrix, but their role in the pathogenesis of photoaging is not clarified. The aim of this study was to investigate whether these aldehydes contribute to alter elastin metabolism and whether topical carbonyl scavengers delay UV-induced skin photoaging. Hairless mice (4-6-week old) daily exposed to UV-A (20 J cm(-2) per day, up to 600 J cm(-2)) exhibited the typical features of photoaging, associated with a significant increase in 4-HNE- and acrolein-adduct content, and elastotic material deposition. Immunofluorescence studies showed the accumulation of 4-HNE adducts on elastin in the dermis of UV-A-exposed mice. This was mimicked in vitro by incubating orcein-elastin with 4-HNE or acrolein, which altered its digestion by leukocyte-elastase, a feature possibly involved in the accumulation of elastotic material. A daily topical application of carnosine completely reversed the development of photoaging alterations and 4-HNE-adduct formation on elastin. These data emphasize the role of 4-HNE and acrolein in the mechanism of photoaging, and the preventive effect of carbonyl scavengers.

Topics: Aldehydes; Animals; Carnosine; Disease Models, Animal; Elasticity; Elastin; Lipid Peroxidation; Mice; Mice, Hairless; Oxidative Stress; Photosensitivity Disorders; Random Allocation; Sensitivity and Specificity; Skin Aging; Ultraviolet Rays

Rupture of abdominal aortic aneurysm (AAA), a major cause of death in the aged population, is characterized by vascular inflammation and matrix degradation. Serum amyloid A (SAA), an acute-phase reactant linked to inflammation and matrix metalloproteinase induction, correlates with aortic dimensions before aneurysm formation in humans. We investigated whether SAA deficiency in mice affects AAA formation during angiotensin II (Ang II) infusion.. Plasma SAA increased ≈60-fold in apoE(-/-) mice 24 hours after intraperitoneal Ang II injection (100 μg/kg; n=4) and ≈15-fold after chronic 28-day Ang II infusion (1000 ng/kg per minute; n=9). AAA incidence and severity after 28-day Ang II infusion was significantly reduced in apoE(-/-) mice lacking both acute-phase SAA isoforms (SAAKO; n=20) compared with apoE(-/-) mice (SAAWT; n=20) as assessed by in vivo ultrasound and ex vivo morphometric analyses, despite a significant increase in systolic blood pressure in SAAKO mice compared with SAAWT mice after Ang II infusion. Atherosclerotic lesion area of the aortic arch was similar in SAAKO and SAAWT mice after 28-day Ang II infusion. Immunostaining detected SAA in AAA tissues of Ang II-infused SAAWT mice that colocalized with macrophages, elastin breaks, and enhanced matrix metalloproteinase activity. Matrix metalloproteinase-2 activity was significantly lower in aortas of SAAKO mice compared with SAAWT mice after 10-day Ang II infusion.. Lack of endogenous acute-phase SAA protects against experimental AAA through a mechanism that may involve reduced matrix metalloproteinase-2 activity.

Topics: Angiotensin II; Animals; Aortic Aneurysm, Abdominal; Apolipoproteins E; Biomarkers; Disease Models, Animal; Elastin; Macrophages; Matrix Metalloproteinase 2; Mice; Mice, Inbred C57BL; Mice, Knockout; Random Allocation; Sensitivity and Specificity; Serum Amyloid A Protein

The ductus arteriosus (DA), a fetal arterial connection between the main pulmonary artery and the descending aorta, normally closes immediately after birth. The oxygen concentration in the blood rises after birth, and in the DA this increase in oxygen concentration causes functional closure, which is induced by smooth muscle contraction. Previous studies have demonstrated that hypoxia and/or oxygenation affect vascular remodeling of various vessels. Therefore, we hypothesized that the rise in oxygen concentration would affect the vascular structure of the DA due to production of proteins secreted from DA smooth muscle cells (SMC).. Liquid chromatography-tandem mass spectrometry was used to comprehensively investigate the secreted proteins in the supernatant of rat DA SMC harvested under hypoxic conditions (1% oxygen) or under normoxic conditions (21% oxygen). We found that the rise in oxygen concentration reduced the secretion of elastin from DA SMC. On reverse transcription-polymerase chain reaction, the expression of elastin mRNA was not significantly changed in DA SMC from hypoxic to normoxic conditions.. Given that elastin forms internal elastic lamina and elastic fibers in the vascular muscle layers, and that a rise in oxygen concentration reduced the secretion of elastin, this suggests that the rise in blood oxygen concentration after birth reduces the secretion of elastin, and therefore may play a role in DA structural remodeling after birth.

Topics: Animals; Blotting, Western; Cells, Cultured; Disease Models, Animal; Ductus Arteriosus; Elastin; Female; Gas Chromatography-Mass Spectrometry; Gene Expression Regulation, Developmental; Hypoxia; Muscle, Smooth, Vascular; Oxygen; Oxygen Consumption; Pregnancy; Pregnancy, Animal; Rats; Rats, Wistar; Reverse Transcriptase Polymerase Chain Reaction; RNA; Vascular Remodeling

TGF-β signaling plays critical roles in the pathogenesis of aneurysms; however, it is still unclear whether its role is protective or destructive. In this study, we investigate the role of SMAD3 in the pathogenesis of calcium chloride (CaCl2)-induced abdominal aortic aneurysms (AAA) in Smad3(-/-), Smad3(+/-) and Smad3(+/+) mice. We find that loss of SMAD3 drastically increases wall thickening of the abdominal aorta. Histological analyses show significant vessel wall remodeling with elastic fiber fragmentation. Remarkably, under polarized light, collagen fibers in the hyperplastic adventitia of Smad3(-/-) mice show extensive reorganization accompanied by loosely packed thin and radial collagen fibers. The expressions of matrix metalloproteinases including MMP2, MMP9, and MMP12 and infiltration of macrophage/T cells are drastically enhanced in the vascular wall of Smad3(-/-) mice. We also observe marked increase of NF-κB and ERK1/2 signaling as well as the expression of nuclear Smad2, Smad4 and TGF-β1 in the vessel wall of Smad3(-/-) mice. In addition, we find that SMAD3 expression is reduced in the dedifferentiated medial smooth muscle-like cells of human AAA patients. These findings provide direct in vivo evidence to support the essential roles of SMAD3 in protecting vessel wall integrity and suppressing inflammation in the pathogenesis of AAAs.

Topics: Animals; Aortic Aneurysm, Abdominal; Atrial Remodeling; Calcium Chloride; Collagen; Disease Models, Animal; Elastin; Extracellular Matrix; Gene Expression Regulation; Inflammation; Leukocytes; Matrix Metalloproteinases; Mice; Mice, Knockout; NF-kappa B; Signal Transduction; Smad2 Protein; Smad3 Protein; Transforming Growth Factor beta

To define the inflammatory cell infiltrate preceding fibrosis in a laryngotracheal stenosis (LTS) murine model.. Prospective controlled murine study.. Laboratory.. Chemomechanical injury mice (n = 44) sustained bleomycin-coated wire-brush injury to the laryngotracheal complex while mechanical injury controls (n = 42) underwent phosphate-buffered saline (PBS)-coated wire-brush injury. Mock surgery controls (n = 34) underwent anterior transcervical tracheal exposure only. Inflammatory and fibrosis protein and gene expression were assessed in each condition. Immunohistochemistry served as a secondary outcome.. In chemomechanical injury mice, there was an upregulation of collagen I (P < .0001, P < .0001), Tgf-β (P = .0023, P = .0008), and elastin (P < .0001, P < .0001) on day 7; acute inflammatory gene Il1β (P = .0027, P = .0008) on day 1; and macrophage gene CD11b (P = .0026, P = .0033) on day 1 vs mechanical and mock controls, respectively. M1 marker inducible nitric oxide synthase (iNOS) expression decreased (P = .0014) while M2 marker Arg1 (P = .0002) increased on day 7 compared with mechanical controls. Flow cytometry demonstrated increased macrophages (P = .0058, day 4) and M1 macrophages (P = .0148, day 4; P = .0343, day 7; P = .0229, day 10) compared to mock controls. There were similarities between chemomechanical and mechanical injury mice with an increase in M2 macrophages at day 10 (P = .0196).. The bleomycin-induced LTS mouse model demonstrated increased macrophages involved with the development of fibrosis. Macrophage immunophenotype suggested that dysregulated M2 macrophages have a role in abnormal laryngotracheal wound healing. These data delineate inflammatory cells and signaling pathways in LTS that may potentially be modulated to lessen fibroblast proliferation and collagen deposition.

Topics: Animals; Bleomycin; Collagen; Disease Models, Animal; Elastin; Flow Cytometry; Gene Expression; Immunohistochemistry; Laryngostenosis; Larynx; Macrophages; Mice; Mice, Inbred C57BL; Prospective Studies; Trachea; Tracheal Stenosis; Transforming Growth Factor beta

Endoscopic submucosal dissection (ESD) can successfully resect large lesions en bloc by using a submucosal injection solution, but the cost of currently available submucosal injection solutions is not satisfactory. The authors' aim was to evaluate the feasibility and effectiveness of a thermally sensitive elastin-like polypeptide (ELP) used as submucosal injection solution in ESD.. We conducted an ex vivo study to determine the optimal concentration of ELPs in rabbits, an in vivo study to evaluate the effectiveness of mucosal elevation in rats, and a large animal study to confirm the feasibility of preclinical application by using conventional clinical procedure in pigs.. ELP (500 μM) was proved to be the optimal injectable submucosal injection solution and elevated mucosa more efficiently than any control. The same concentration of ELP exhibited an equivalent effectiveness of mucosal elevation, the retention of the elevation, and minimal bleeding with sodium hyaluronate. The ESD procedure time with 500 μM ELP in a preclinical study with pigs was significantly shorter than with any other concentration of ELP and normal saline solution.. Use of ELP as submucosal injection solution was feasible, with higher and longer-lasting elevation and fewer adverse events.

Topics: Animals; Disease Models, Animal; Dissection; Elastin; Endoscopy, Gastrointestinal; Feasibility Studies; Gastric Mucosa; Injections, Intralesional; Male; Neoplasms, Experimental; Rabbits; Rats; Rats, Sprague-Dawley; Stomach Neoplasms; Swine; Swine, Miniature; Temperature; Treatment Outcome

Autophagy regulates cellular homeostasis and integrates the cellular pro-survival machinery. We investigated the role of autophagy in the natural history of murine abdominal aortic aneurysms (AAA). ApoE(-/-) mice were implanted with saline- or angiotensin II (Ang-II)-filled miniosmotic pumps then treated with either the autophagy inhibitor chloroquine (CQ; 50 mg·(kg body mass)(-1)·day(-1), by intraperitoneal injection) or saline. Ang-II-elicited aneurysmal expansion of the suprarenal aorta coupled with thrombus formation were apparent 8 weeks later. CQ had no impact on the incidence (50% for Ang-II compared with 46.2% for Ang-II + CQ; P = NS) and categorical distribution of aneurysms. The markedly reduced survival rate observed with Ang-II (57.1% for Ang-II compared with 100% for saline; P < 0.05) was unaffected by CQ (61.5% for Ang-II + CQ; P = NS compared with Ang-II). CQ did not affect the mean maximum suprarenal aortic diameter (1.91 ± 0.19 mm for Ang-II compared with 1.97 ± 0.21 mm for Ang-II + CQ; P = NS). Elastin fragmentation, collagen accumulation, and smooth muscle attrition, which were higher in Ang-II-treated mice, were unaffected by CQ treatment. Long-term CQ administration does not affect the natural history and prognosis of experimental AAA, suggesting that global loss of autophagy is unlikely to be a causal factor in the development of aortic aneurysms. Manipulation of autophagy as a mechanism to reduce AAA may need re-evaluation.

Topics: Angiotensin II; Animals; Aorta, Abdominal; Aortic Aneurysm, Abdominal; Apolipoproteins E; Autophagy; Chloroquine; Collagen; Disease Models, Animal; Disease Progression; Elastin; Male; Mice, Inbred C57BL; Mice, Knockout; Time Factors

Well-defined inflammation, proliferation, and maturation phases orchestrate the remodeling of the injured myocardium after myocardial infarction (MI) by controlling the formation of new extracellular matrix. The extracellular matrix consists mainly of collagen but also fractions of elastin. It is thought that elastin is responsible for maintaining elastic properties of the myocardium, thus reducing the risk of premature rupture. An elastin/tropoelastin-specific contrast agent (Gd-ESMA) was used to image tropoelastin and mature elastin fibers for in vivo assessment of extracellular matrix remodeling post-MI.. Gd-ESMA enhancement was studied in a mouse model of myocardial infarction using a 7 T MRI scanner and results were compared to those achieved after injection of a nonspecific control contrast agent, gadolinium-diethylenetriamine pentaacetic acid (Gd-DTPA). In the infarcted tissue, Gd-ESMA uptake (measured as R1 relaxation rate) steadily increased from day 3 to day 21 as a result of the synthesis of elastin/tropoelastin. R1 values were in good agreement with histological findings. A similar R1 behavior was observed in the remote myocardium. No mature cross-linked elastin was found at any time point. In contrast, Gd-DTPA uptake was only observed in the infarct with no changes in R1 values between 3 and 21 days post-MI.. We demonstrate the feasibility of in vivo imaging of extracellular matrix remodeling post-MI using a tropoelastin/elastin binding MR contrast agent, Gd-ESMA. We found that tropoelastin is the main contributor to the increased MRI signal at late stages of MI where its augmentation in areas of infarction was in good agreement with the R1 increase.

Topics: Animals; Biomarkers; Contrast Media; Disease Models, Animal; Elastin; Feasibility Studies; Female; Gadolinium DTPA; Injections, Intravenous; Magnetic Resonance Imaging, Cine; Mice, Inbred C57BL; Myocardial Infarction; Myocardium; Predictive Value of Tests; Protein Binding; Tropoelastin; Ventricular Remodeling

The prevalence of arterial stiffness increases with age, whereas the level of the aging-suppressor protein klotho decreases with age. The objective of this study is to assess whether haplodeficiency of klotho gene causes arterial stiffness and to investigate the underlying mechanism. Pulse wave velocity, a direct measure of arterial stiffness, was increased significantly in klotho heterozygous (klotho(+/-)) mice versus their age-matched wild-type (WT) littermates, suggesting that haplodeficiency of klotho causes arterial stiffening. Notably, plasma aldosterone levels were elevated significantly in klotho(+/-) mice. Treatment with eplerenone (6 mg/kg per day IP), an aldosterone receptor blocker, abolished klotho deficiency-induced arterial stiffening in klotho(+/-) mice. Klotho deficiency was associated with increased collagen and decreased elastin contents in the media of aortas. In addition, arterial matrix metalloproteinase-2, matrix metalloproteinase-9, and transforming growth factor-β1 expression and myofibroblast differentiation were increased in klotho(+/-) mice. These klotho deficiency-related changes can be blocked by eplerenone. Protein expression of scleraxis, a transcription factor for collagen synthesis, and LC3-II/LC3-I, an index of autophagy, were upregulated in aortas of klotho(+/-) mice, which can be abolished by eplerenone. In cultured mouse aortic smooth muscle cells, aldosterone increased collagen-1 expression that can be completely eliminated by small interfering RNA knockdown of scleraxis. Interestingly, aldosterone decreased elastin levels in smooth muscle cells, which can be abolished by small interfering RNA knockdown of Beclin-1, an autophagy-related gene. In conclusion, this study demonstrated for the first time that klotho deficiency-induced arterial stiffening may involve aldosterone-mediated upregulation of scleraxis and induction of autophagy, which led to increased collagen-1 expression and decreased elastin levels, respectively.

Topics: Aldosterone; Animals; Apoptosis Regulatory Proteins; Autophagy; Basic Helix-Loop-Helix Transcription Factors; Beclin-1; Collagen Type I; Disease Models, Animal; Elastin; Glucuronidase; Haploidy; Haploinsufficiency; Klotho Proteins; Matrix Metalloproteinase 2; Matrix Metalloproteinase 9; Mice; Mice, Knockout; Transforming Growth Factor beta1; Up-Regulation; Vascular Stiffness

Thrombomodulin (TM), a glycoprotein constitutively expressed in the endothelium, is well known for its anticoagulant and anti-inflammatory properties. Paradoxically, we recently found that monocytic membrane-bound TM (ie, endogenous TM expression in monocytes) triggers lipopolysaccharide- and gram-negative bacteria-induced inflammatory responses. However, the significance of membrane-bound TM in chronic sterile vascular inflammation and the development of abdominal aortic aneurysm (AAA) remains undetermined.. Implicating a potential role for membrane-bound TM in AAA, we found that TM signals were predominantly localized to macrophages and vascular smooth muscle cells in human aneurysm specimens. Characterization of the CaCl2-induced AAA in mice revealed that during aneurysm development, TM expression was mainly localized in infiltrating macrophages and vascular smooth muscle cells. To investigate the function of membrane-bound TM in vivo, transgenic mice with myeloid- (LysMcre/TM(flox/flox)) and vascular smooth muscle cell-specific (SM22-cre(tg)/TM(flox/flox)) TM ablation and their respective wild-type controls (TM(flox/flox) and SM22-cre(tg)/TM(+/+)) were generated. In the mouse CaCl2-induced AAA model, deficiency of myeloid TM, but not vascular smooth muscle cell TM, inhibited macrophage accumulation, attenuated proinflammatory cytokine and matrix metalloproteinase-9 production, and finally mitigated elastin destruction and aortic dilatation. In vitro TM-deficient monocytes/macrophages, versus TM wild-type counterparts, exhibited attenuation of proinflammatory mediator expression, adhesion to endothelial cells, and generation of reactive oxygen species. Consistently, myeloid TM-deficient hyperlipidemic mice (ApoE(-/-)/LysMcre/TM(flox/flox)) were resistant to AAA formation induced by angiotensin II infusion, along with reduced macrophage infiltration, suppressed matrix metalloproteinase activities, and diminished oxidative stress.. Membrane-bound TM in macrophages plays an essential role in the development of AAA by enhancing proinflammatory mediator elaboration, macrophage recruitment, and oxidative stress.

Topics: Angiotensin II; Animals; Aorta, Abdominal; Aortic Aneurysm, Abdominal; Aortitis; Calcium Chloride; Cell Membrane; Cells, Cultured; Chemotaxis; Disease Models, Animal; Elastin; Human Umbilical Vein Endothelial Cells; Humans; Inflammation Mediators; Macrophages, Peritoneal; Matrix Metalloproteinase 9; Mice, Inbred C57BL; Mice, Knockout; Muscle, Smooth, Vascular; Myocytes, Smooth Muscle; Oxidative Stress; Retrospective Studies; RNA Interference; Signal Transduction; Thrombomodulin; Time Factors; Transfection

Sirtuin-1 (SirT1), a nicotinamide adenine dinucleotide(+)-dependent deacetylase, is a key enzyme in the cellular response to metabolic, inflammatory, and oxidative stresses; however, the role of endogenous SirT1 in the vasculature has not been fully elucidated. Our goal was to evaluate the role of vascular smooth muscle SirT1 in the physiological response of the aortic wall to angiotensin II, a potent hypertrophic, oxidant, and inflammatory stimulus.. Mice lacking SirT1 in vascular smooth muscle (ie, smooth muscle SirT1 knockout) had drastically high mortality (70%) caused by aortic dissection after angiotensin II infusion (1 mg/kg per day) but not after an equipotent dose of norepinephrine, despite comparable blood pressure increases. Smooth muscle SirT1 knockout mice did not show any abnormal aortic morphology or blood pressure compared with wild-type littermates. Nonetheless, in response to angiotensin II, aortas from smooth muscle SirT1 knockout mice had severely disorganized elastic lamellae with frequent elastin breaks, increased oxidant production, and aortic stiffness compared with angiotensin II-treated wild-type mice. Matrix metalloproteinase expression and activity were increased in the aortas of angiotensin II-treated smooth muscle SirT1 knockout mice and were prevented in mice overexpressing SirT1 in vascular smooth muscle or with use of the oxidant scavenger tempol.. Endogenous SirT1 in aortic smooth muscle is required to maintain the structural integrity of the aortic wall in response to oxidant and inflammatory stimuli, at least in part, by suppressing oxidant-induced matrix metalloproteinase activity. SirT1 activators could potentially be a novel therapeutic approach to prevent aortic dissection and rupture in patients at risk, such as those with hypertension or genetic disorders, such as Marfan's syndrome.

Topics: Angiotensin II; Animals; Aorta, Thoracic; Aortic Aneurysm; Aortic Dissection; Cells, Cultured; Cyclic N-Oxides; Disease Models, Animal; Elastic Tissue; Elastin; Free Radical Scavengers; Hypertension; Matrix Metalloproteinases; Mice, Inbred C57BL; Mice, Knockout; Muscle, Smooth, Vascular; Myocytes, Smooth Muscle; Sirtuin 1; Spin Labels; Time Factors

Deep venous thrombosis is a common vascular problem with long-term complications including post-thrombotic syndrome. Post-thrombotic syndrome consists of leg pain, swelling and ulceration that is related to incomplete or maladaptive resolution of the venous thrombus as well as loss of compliance of the vein wall. We examine the role of metalloproteinase-9 (MMP-9), a gene important in extracellular remodeling in other vascular diseases, in mediating thrombus resolution and biomechanical changes of the vein wall.. The effects of targeted deletion of MMP-9 were studied in an in vivo murine model of thrombus resolution using the FVB strain of mice. MMP-9 expression and activity significantly increased on day 3 after DVT. The lack of MMP-9 impaired thrombus resolution by 27% and this phenotype was rescued by the transplantation of wildtype bone marrow cells. Using novel biomechanical techniques, we demonstrated that the lack of MMP-9 significantly decreased thrombus-induced loss of vein wall compliance. Biomechanical analysis of the contribution of individual structural components showed that MMP-9 affected the elasticity of the extracellular matrix and collagen-elastin fibers. Biochemical and histological analyses correlated with these biomechanical effects as thrombi of mice lacking MMP-9 had significantly fewer macrophages and collagen as compared to those of wildtype mice.. MMP-9 mediates thrombus-induced loss of vein wall compliance by increasing stiffness of the extracellular matrix and collagen-elastin fibers during thrombus resolution. MMP-9 also mediates macrophage and collagen content of the resolving thrombus and bone-marrow derived MMP-9 plays a role in resolution of thrombus mass. These disparate effects of MMP-9 on various aspects of thrombus illustrate the complexity of individual protease function on biomechanical and morphometric aspects of thrombus resolution.

Topics: Animals; Biomechanical Phenomena; Bone Marrow; Collagen; Disease Models, Animal; Elastin; Extracellular Matrix; Gene Deletion; Immunohistochemistry; Inflammation; Matrix Metalloproteinase 9; Mice; Veins; Venous Thrombosis

Matrix metalloproteinases (MMPs)-mediated extracellular matrix destruction is the major cause of development and progression of abdominal aortic aneurysms. Systemic treatments of MMP inhibitors have shown effectiveness in animal models, but it did not translate to clinical success either because of low doses used or systemic side effects of MMP inhibitors. We propose a targeted nanoparticle (NP)-based delivery of MMP inhibitor at low doses to the abdominal aortic aneurysms site. Such therapy will be an attractive option for preventing expansion of aneurysms in patients without systemic side effects.. Our previous study showed that poly(d,l-lactide) NPs conjugated with an antielastin antibody could be targeted to the site of an aneurysm in a rat model of abdominal aortic aneurysms. In the study reported here, we tested whether such targeted NPs could deliver the MMP inhibitor batimastat (BB-94) to the site of an aneurysm and prevent aneurysmal growth.. Poly(d,l-lactide) NPs were loaded with BB-94 and conjugated with an elastin antibody. Intravenous injections of elastin antibody-conjugated BB-94-loaded NPs targeted the site of aneurysms and delivered BB-94 in a calcium chloride injury-induced abdominal aortic aneurysms in rats. Such targeted delivery inhibited MMP activity, elastin degradation, calcification, and aneurysmal development in the aorta (269% expansion in control versus 40% elastin antibody-conjugated BB-94-loaded NPs) at a low dose of BB-94. The systemic administration of BB-94 alone at the same dose was ineffective in producing MMP inhibition.. Targeted delivery of MMP inhibitors using NPs may be an attractive strategy to inhibit aneurysmal progression.

Topics: Animals; Aorta, Abdominal; Aortic Aneurysm, Abdominal; Calcium Chloride; Chemistry, Pharmaceutical; Disease Models, Animal; Disease Progression; Drug Carriers; Elastin; Immunoconjugates; Macrophages; Male; Matrix Metalloproteinase Inhibitors; Matrix Metalloproteinases; Mice; Nanoparticles; Phenylalanine; Polyesters; Proteolysis; Rats, Sprague-Dawley; RAW 264.7 Cells; Thiophenes; Time Factors; Vascular Calcification

The passive properties of the venous wall are important for the compliance function of the venous system. The objective of this study was to quantify the passive biomechanical response and structural growth and remodeling of veins subjected to chronic venous reflux and hypertension.. To investigate the effects of venous reflux on venous mechanics, the tricuspid valve was injured in a canine model by disrupting the chordae tendineae. The conventional inflation-extension protocol in conjunction with intravascular ultrasound was used to investigate the passive biomechanical response of both control common iliac veins (n = 9 dogs) and common iliac veins subjected to 8 weeks of venous reflux and hypertension (n = 9 dogs). The changes in vein wall thickness and constituent composition were quantified by multiphoton microscopy and histologic evaluation.. Biomechanical results indicate that the veins became less compliant when exposed to 8 weeks of chronic venous reflux and hypertension. The mechanical stiffening was found to be associated with a significant increase in wall thickness (P < .05) and collagen-to-elastin ratio (P < .05). After 8 weeks of chronic reflux and hypertension, the circumferential vein wall stress was significantly reduced (P < .05) because of wall thickening, although it was not restored to control levels.. The growth and remodeling of the venous wall reduces the wall stress, but the stress remains higher than at baseline at 8 weeks. The compliance of the veins also decreases because of the increase in wall thickness and remodeling of the microstructure of the venous wall. These findings provide insight into potential adaptations of the venous system in reflux and hypertension.

Topics: Animals; Collagen; Compliance; Disease Models, Animal; Dogs; Elastin; Femoral Vein; Hypertension; Iliac Vein; Stress, Mechanical; Venous Insufficiency

Abdominal aortic aneurysms (AAAs) are associated with oxidative stress and inflammatory response. We investigated the hypothesis that the known antioxidant ascorbic acid, which can also promote elastin and collagen production by smooth muscle cells, would prevent AAA formation in a rat model.. An intraluminal elastase and extraluminal calcium chloride-induced rat AAA model was used, and the animals were divided into three groups: control (group C, n = 18), the aorta wrapped with a saline-impregnated gelatin hydrogel sheet (group G, n = 18), and the aorta wrapped with a gelatin hydrogel sheet incorporating ascorbic acid (group A, n = 18). Wrapping of the sheet was completed at the end of treatment for AAA creation. The aortic dilatation ratio was measured, and aortic tissues were further examined for oxidative stress and oxidative DNA damage using biochemical and histologic techniques.. Aortic dilatation at both 4 and 8 weeks was inhibited in group A (dilatation ratio [%] at 4 weeks: 186.2 ± 21.8 in group C, 152.3 ± 10.2 in group G, 126.8 ± 11.6 in group A; P < .0001; dilatation ratio [%] at 8 weeks: 219.3 ± 37.5 in group C, 194.0 ± 11.6 in group G, 145.7 ± 8.3 in group A; P = .0002). Elastin and collagen content were significantly preserved in group A (elastin, P = .0015; collagen, P < .0001). The messenger RNA expressions of matrix metalloproteinase (MMP)-9, monocyte chemotactic protein-1, interleukin-1β, and tissue necrosis factor-α (P = .0024, P < .0001, P < .0001, and P < .0001, respectively) were downregulated in group A (P = .0024), whereas tissue inhibitors of metalloproteinase (TIMP)-1 and TIMP-2 were both upregulated in group A (TIMP-1, P = .0014; TIMP-2, P < .0001). Gelatin zymography showed activities of pro-MMP-2, MMP-2, and MMP-9 were significantly suppressed in group C (P < .0001 for each). Reactive oxygen species expression and 8-hydroxydeoxyguanosine and cluster of differentiation 68 staining were significantly suppressed in group A (reactive oxygen species expression, P < .0001; 8-hydroxydeoxyguanosine-positive cells, P < .0001; cluster of differentiation 68 positive cells, P < .0001).. Controlled release of ascorbic acid using gelatin hydrogel sheet-attenuated AAA formation through antioxidant and anti-inflammatory effect, regulation of MMP-2, TIMP-1, and TIMP-2, and preserving elastin and collagen in this animal model.

Topics: Animals; Antioxidants; Aorta, Abdominal; Aortic Aneurysm, Abdominal; Ascorbic Acid; Calcium Chloride; Chemistry, Pharmaceutical; Chemokine CCL2; Collagen; Delayed-Action Preparations; Dilatation, Pathologic; Disease Models, Animal; DNA Damage; Drug Carriers; Elastin; Gelatin; Gene Expression Regulation; Hydrogels; Inflammation Mediators; Interleukin-1beta; Male; Matrix Metalloproteinase 9; Oxidative Stress; Pancreatic Elastase; Rats; Rats, Sprague-Dawley; RNA, Messenger; Time Factors; Tissue Inhibitor of Metalloproteinase-1; Tissue Inhibitor of Metalloproteinase-2; Tumor Necrosis Factor-alpha

Aortic stiffening commonly occurs in hypertension and further elevates systolic pressure. Hypertension is also associated with vascular inflammation and increased mechanical stretch. The interplay between inflammation, mechanical stretch, and aortic stiffening in hypertension remains undefined.. Our aim was to determine the role of inflammation and mechanical stretch in aortic stiffening.. Chronic angiotensin II infusion caused marked aortic adventitial collagen deposition, as quantified by Masson trichrome blue staining and biochemically by hydroxyproline content, in wild-type but not in recombination activating gene-1-deficient mice. Aortic compliance, defined by ex vivo measurements of stress-strain curves, was reduced by chronic angiotensin II infusion in wild-type mice (P<0.01) but not in recombination activating gene-1-deficient mice (P<0.05). Adoptive transfer of T-cells to recombination activating gene-1-deficient mice restored aortic collagen deposition and stiffness to values observed in wild-type mice. Mice lacking the T-cell-derived cytokine interleukin 17a were also protected against aortic stiffening. In additional studies, we found that blood pressure normalization by treatment with hydralazine and hydrochlorothiazide prevented angiotensin II-induced vascular T-cell infiltration, aortic stiffening, and collagen deposition. Finally, we found that mechanical stretch induces the expression of collagen 1α1, 3α1, and 5a1 in cultured aortic fibroblasts in a p38 mitogen-activated protein kinase-dependent fashion, and that inhibition of p38 prevented angiotensin II-induced aortic stiffening in vivo. Interleukin 17a also induced collagen 3a1 expression via the activation of p38 mitogen-activated protein kinase.. Our data define a pathway in which inflammation and mechanical stretch lead to vascular inflammation that promotes collagen deposition. The resultant increase in aortic stiffness likely further worsens systolic hypertension and its attendant end-organ damage.

Topics: Adoptive Transfer; Angiotensin II; Animals; Aortic Diseases; CD4 Antigens; CD8 Antigens; Cells, Cultured; Collagen; Disease Models, Animal; Elastin; Fibroblasts; Homeodomain Proteins; Hypertension; Inflammation; Interleukin-17; Male; Mice; Mice, Knockout; p38 Mitogen-Activated Protein Kinases; Stress, Mechanical; T-Lymphocytes; Vascular Stiffness; Vasculitis; Vasoconstrictor Agents

To prospectively evaluate an elastin-specific MR contrast agent (ESMA) for in vivo targeting of elastic fibers in myocardial infarction (MI) and postinfarction scar remodeling.. MI was induced in C57BL/6J mice (n=40) by permanent ligation of the left anterior descending coronary artery. MRI was performed at 7 and 21 days after MI. The merits of gadolinium-based ESMA (Gd-ESMA) were compared with gadopentetic acid (Gd-DTPA) for infarct size determination, contrast-to-noise ratio (CNR), and enhancement kinetics. Specific binding in vivo was evaluated by blocking the molecular target using nonparamagnetic lanthanum-ESMA. In vivo imaging results were confirmed by postmortem triphenyltetrazolium chloride staining, elastica van Gieson staining, and Western blotting. Delayed enhancement MRI revealed prolonged enhancement of Gd-ESMA in the postischemic scar compared with Gd-DTPA. Infarct size measurements showed good agreement between Gd-ESMA and Gd-DTPA and were confirmed by ex vivo triphenyltetrazolium chloride staining. Preinjection of the blocking lanthanum-ESMA resulted in significantly lower CNR of Gd-ESMA at the infarct site (P=0.0019). Although no significant differences in CNR were observed between delayed enhancement imaging and Gd-DTPA between days 7 and 21 (1.8± versus 3.8; P=ns), Gd-ESMA showed markedly higher CNR on day 21 after MI (14.1 versus 4.9; P=0.0032), which correlated with increased synthesis of tropoelastin detected by Western blot analysis and histology. Higher CNR values for Gd-ESMA further correlated with improved ejection fraction of the mice on day 21 after MI.. Gd-ESMA enables targeting of elastin within the infarct scar in a mouse model of MI. The imaging properties of Gd-ESMA allow quantification of intrascar elastin content in vivo and thereby provide potential for noninvasive characterization of postinfarction scar remodeling.

Topics: Animals; Cicatrix; Contrast Media; Coronary Vessels; Disease Models, Animal; Elastic Tissue; Elastin; Female; Follow-Up Studies; Gadolinium DTPA; Magnetic Resonance Imaging, Cine; Mice; Mice, Inbred C57BL; Myocardial Infarction; Myocardium; Predictive Value of Tests; Prospective Studies; Time Factors

The purpose of this research was to study the effects of age and genetic alterations in key connective tissue proteins on susceptibility to experimental glaucoma in mice. We used mice haploinsufficient in the elastin gene (EH) and mice without both alleles of the fibromodulin gene (FM KO) and their wild type (WT) littermates of B6 and CD1 strains, respectively. FM KO mice were tested at two ages: 2 months and 12 months. Intraocular pressure (IOP) was measured by Tonolab tonometer, axial lengths and widths measured by digital caliper post-enucleation, and chronic glaucoma damage was measured using a bead injection model and optic nerve axon counts. IOP in EH mice was not significantly different from WT, but FM KO were slightly lower than their controls (p = 0.04). Loss of retinal ganglion cell (RGC) axons was somewhat, but not significantly greater in young EH and younger or older FM KO strains than in age-matched controls (p = 0.48, 0.34, 0.20, respectively, multivariable regression adjusting for IOP exposure). Older CD1 mice lost significantly more RGC axons than younger CD1 (p = 0.01, multivariable regression). The CD1 mouse strain showed age-dependence of experimental glaucoma damage to RGC in the opposite, and more expected, direction than in B6 mice in which older mice are more resistant to damage. Genetic alteration in two genes that are constituents of sclera, fibromodulin and elastin do not significantly affect RGC loss.

Topics: Aging; Animals; Axons; Biomechanical Phenomena; Cell Count; Connective Tissue; Disease Models, Animal; DNA; Elastin; Extracellular Matrix Proteins; Eye Proteins; Fibromodulin; Genetic Predisposition to Disease; Glaucoma; Intraocular Pressure; Mice; Mice, Knockout; Mutation; Optic Nerve; Proteoglycans; Retinal Ganglion Cells; Sclera

Elastin (Eln) insufficiency in mice and humans is associated with hypertension and altered structure and mechanical properties of large arteries. However, it is not known to what extent functional or structural changes in resistance arteries contribute to the elevated blood pressure that is characteristic of Eln insufficiency. Here, we investigated how Eln insufficiency affects the structure and function of the resistance vasculature. A functional profile of resistance vasculature in Eln(+/-) mice was generated by assessing small mesenteric artery (MA) contractile and vasodilatory responses to vasoactive agents. We found that Eln haploinsufficiency had a modest effect on phenylephrine-induced vasoconstriction, whereas ANG II-evoked vasoconstriction was markedly increased. Blockade of ANG II type 2 receptors with PD-123319 or modulation of Rho kinase activity with the inhibitor Y-27632 attenuated the augmented vasoconstriction, whereas acute Y-27632 administration normalized blood pressure in Eln(+/-) mice. Sodium nitroprusside- and isoproterenol-induced vasodilatation were normal, whereas ACh-induced vasodilatation was severely impaired in Eln(+/-) MAs. Histologically, the number of smooth muscle layers did not change in Eln(+/-) MAs; however, an additional discontinuous layer of Eln appeared between the smooth muscle layers that was absent in wild-type arteries. We conclude that high blood pressure arising from Eln insufficiency is due partly to permanent changes in vascular tone as a result of increased sensitivity of the resistance vasculature to circulating ANG II and to impaired vasodilatory mechanisms arising from endothelial dysfunction characterized by impaired endothelium-dependent vasodilatation. Eln insufficiency causes augmented ANG II-induced vasoconstriction in part through a novel mechanism that facilitates contraction evoked by ANG II type 2 receptors and altered G protein signaling.

Topics: Angiotensin II; Animals; Arterial Pressure; Calcium; Disease Models, Animal; Dose-Response Relationship, Drug; Elastin; Endothelium, Vascular; Genetic Predisposition to Disease; Haploinsufficiency; Hemizygote; Hypertension; Male; Mesenteric Arteries; Mice; Mice, Inbred C57BL; Mice, Knockout; Phenotype; Protein Kinase Inhibitors; Receptor, Angiotensin, Type 2; rho-Associated Kinases; Signal Transduction; Vascular Resistance; Vasoconstriction; Vasoconstrictor Agents; Vasodilation; Vasodilator Agents

Development of thoracic aortic aneurysms is the most significant clinical phenotype in patients with Marfan syndrome. An inflammatory response has been described in advanced stages of the disease. Because the hallmark of vascular inflammation is local interleukin-6 (IL-6) secretion, we explored the role of this proinflammatory cytokine in the formation of aortic aneurysms and rupture in hypomorphic fibrillin-deficient mice (mgR/mgR).. MgR/mgR mice developed ascending aortic aneurysms with significant dilation of the ascending aorta by 12 weeks (2.7 ± 0.1 and 1.3 ± 0.1 for mgR/mgR versus wild-type mice, respectively; P<0.001). IL-6 signaling was increased in mgR/mgR aortas measured by increases in IL-6 and SOCS3 mRNA transcripts (P<0.05) and in cytokine secretion of IL-6, MCP-1, and GM-CSF (P<0.05). To investigate the role of IL-6 signaling, we generated mgR homozygous mice with IL-6 deficiency (DKO). The extracellular matrix of mgR/mgR mice showed significant disruption of elastin and the presence of dysregulated collagen deposition in the medial-adventitial border by second harmonic generation multiphoton autofluorescence microscopy. DKO mice exhibited less elastin and collagen degeneration than mgR/mgR mice, which was associated with decreased activity of matrix metalloproteinase-9 and had significantly reduced aortic dilation (1.0 ± 0.1 versus 1.6 ± 0.2 mm change from baseline, DKO versus mgR/mgR, P<0.05) that did not affect rupture and survival.. Activation of IL-6-STAT3 signaling contributes to aneurysmal dilation in mgR/mgR mice through increased MMP-9 activity, aggravating extracellular matrix degradation.

Topics: Animals; Aorta; Aortic Aneurysm, Thoracic; Aortic Rupture; Chemokine CCL2; Collagen; Dilatation, Pathologic; Disease Models, Animal; Elastin; Extracellular Matrix; Fibrillin-1; Fibrillins; Granulocyte-Macrophage Colony-Stimulating Factor; Interleukin-6; Marfan Syndrome; Matrix Metalloproteinase 9; Mice; Mice, Inbred C57BL; Mice, Knockout; Microfilament Proteins; RNA, Messenger; Severity of Illness Index; Signal Transduction; STAT3 Transcription Factor; Suppressor of Cytokine Signaling 3 Protein; Suppressor of Cytokine Signaling Proteins; Time Factors; Up-Regulation

To compare delayed-enhancement (DE) magnetic resonance (MR) imaging with an elastin-specific contrast agent and unenhanced black-blood (BB) MR imaging with regard to vessel wall delineation and assessment of vascular remodeling and to test the prospective value for predicting plaque disruption in a rabbit model of atherosclerosis.. All procedures were approved by the animal ethics committee. Atherosclerosis was induced in 14 New Zealand White rabbits by means of a 1% cholesterol diet and endothelial denudation. Plaque disruption was triggered with Russell's viper venom and histamine. Animals with atherosclerosis were imaged before triggering to identify plaques and vascular remodeling and after triggering to identify thrombus. Plaques were classified as nondisrupted (stable) or disrupted (vulnerable). Control rabbits fed a regular diet were imaged twice. Unenhanced T1-weighted BB MR imaging, DE MR imaging with an elastin-specific contrast agent, and T1 mapping were used to assess vascular remodeling and calculate the plaque area and vessel wall relaxation rate (R1 = 1/T1). Elastin was quantified by using elastica-van Gieson stain. Group comparisons were analyzed with the Mann-Whitney or paired t test. Agreement between methods was performed with Bland-Altman analysis.. Unenhanced T1-weighted BB MR imaging and DE MR imaging showed that, compared with nondisrupted plaques, disrupted plaques had larger plaque area (T1-weighted BB MR imaging: 5.1 mm(2) vs 5.7 mm(2); DE MR imaging: 6.0 mm(2) vs 7.9 mm(2); P < .001) and vessel area (T1-weighted BB MR imaging: 11.8 mm(2) vs 14.3 mm(2); DE MR imaging: 10.8 mm(2) vs 13.9 mm(2); P < .001) and underwent positive remodeling. Assessment of positive remodeling with DE MR imaging enabled better prediction of plaque disruption compared to that with unenhanced T1-weighted BB imaging (sensitivity: 83.7% vs 58.1%). DE MR imaging showed a stronger agreement with histologic findings, whereas the vessel area was overestimated with unenhanced T1-weighted BB imaging.. Compared with unenhanced T1-weighted BB MR imaging, DE MR imaging with an elastin-specific contrast agent enables more accurate assessment of vascular remodeling in the prediction of vulnerable plaque.

Topics: Animals; Aorta, Abdominal; Cholesterol, Dietary; Contrast Media; Disease Models, Animal; Elastin; Image Processing, Computer-Assisted; Magnetic Resonance Angiography; Plaque, Atherosclerotic; Prospective Studies; Rabbits

An aortic aneurysm (AA) is caused by atherosclerosis with chronic inflammation. Mesenchymal stem cells (MSCs) have potential anti-inflammatory properties. In this study, we examined whether an already-formed AA can be treated by intravenous injection of bone marrow-derived (BM)-MSCs in a mouse model.. AA was induced in apolipoprotein E-deficient mice by angiotensin II-infusion for 28 days through sub-cutaneous osmotic mini-pumps. After that, 1 × 10(6) BM-MSCs (in 0.2 ml saline) or 0.2 ml saline as a control was injected via the tail vein. Mice were sacrificed at 2 (saline group n = 10, BM-MSC group n = 10), 4 (saline group n = 6, BM-MSC group n = 7) or 8 weeks (saline group n = 5, BM-MSC group n = 6) after injection. The aortic tissues of each group were dissected. Aortic diameter, elastin content, matrix metalloproteinase (MMP)-2 and -9 enzymatic activity and cytokine concentrations were measured, as was macrophage infiltration, which was also evaluated histologically.. The incidence of AA in the BM-MSC group was reduced at 2 weeks (BM-MSC 40% vs saline 100%, P < 0.05), and aortic diameter was reduced at 2 and 4 weeks (2 weeks: 1.40 vs 2.29 mm, P < 0.001; 4 weeks: 1.73 vs 2.32 mm, P < 0.05). The enzymatic activities of MMP-2 and -9 were reduced in the BM-MSC group at 2 weeks (active-MMP-2: 0.28 vs 0.45 unit/ml, P < 0.05; active-MMP-9: 0.16 vs 0.34 unit/ml, P < 0.05). Inflammatory cytokines were down-regulated in the BM-MSC group (interleukin-6: 2 weeks: 1475.6 vs 3399.5 pg/ml, P < 0.05; 4 weeks: 2184.7 vs 3712.8 pg/ml, P < 0.05 and monocyte chemotactic protein-1: 2 weeks: 208.0 vs 352.7 pg/ml, P < 0.05) and insulin-like growth factor (IGF)-1 and tissue inhibitor of metalloproteinase (TIMP)-2 were up-regulated in the BM-MSC group at 2 weeks (IGF-1: 4.7 vs 2.0 ng/ml, P < 0.05; TIMP-2: 9.5 vs 4.0 ng/ml, P < 0.001). BM-MSC injection inhibited infiltration of M1 macrophages and preserved the construction of elastin.. Our results suggest that BM-MSCs might be an effective treatment for AA. Further investigation is necessary to optimize the injected dosage and the frequency of BM-MSCs to prevent a transient effect.

Topics: Administration, Intravenous; Animals; Aorta; Aortic Aneurysm; Bone Marrow Transplantation; Disease Models, Animal; Elastin; Male; Matrix Metalloproteinase 2; Matrix Metalloproteinase 9; Mesenchymal Stem Cell Transplantation; Mice; Mice, Transgenic

Postnatal lung development requires coordination of three processes (surface area expansion, microvascular growth, and matrix remodeling). Because normal elastin structure is important for lung morphogenesis, because physiological remodeling of lung elastin has never been defined, and because elastin remodeling is angiogenic, we sought to test the hypothesis that, during lung development, elastin is remodeled in a defined temporal-spatial pattern, that a novel protease is associated with this remodeling, and that angiogenesis is associated with elastin remodeling. By elastin in situ zymography, lung elastin remodeling increased 24-fold between embryonic day (E) 15.5 and postnatal day (PND) 14. Remodeling was restricted to major vessels and airways on PND1 with a sevenfold increase in alveolar wall elastin remodeling from PND1 to PND14. By inhibition assays and literature review, we identified chymotrypsin-like elastase 1 (CELA1) as a potential mediator of elastin remodeling. CELA1 mRNA levels increased 12-fold from E15.5 to PND9, and protein levels increased 3.4-fold from E18.5 to PND9. By costaining experiments, the temporal-spatial pattern of CELA1 expression matched that of elastin remodeling, and 58-85% of CELA1(+) cells were <10 μm from an elastase signal. An association between elastin remodeling and angiogenesis was tested by similar methods. At PND7 and PND14, 60-95% of angiogenin(+) cells were associated with elastin remodeling. Both elastase inhibition and CELA1 silencing impaired angiogenesis in vitro. Our data defines the temporal-spatial pattern of elastin remodeling during lung development, demonstrates an association of this remodeling with CELA1, and supports a role for elastin remodeling in regulating angiogenesis.

Topics: Animals; Animals, Newborn; Chymases; Disease Models, Animal; Elastin; Lung; Mice; Mice, Inbred C57BL; Mice, Transgenic; Pancreatic Elastase; Pulmonary Alveoli

Ascending aortic dissection and rupture remain a life-threatening complication in patients with Marfan syndrome. The extracellular matrix provides strength and elastic recoil to the aortic wall, thereby preventing radial expansion. We have previously shown that ascending aortic aneurysm formation in Marfan mice (Fbn1(C1039G/+)) is associated with decreased aortic wall elastogenesis and increased elastin breakdown. In this study, we test the feasibility of quantifying aortic wall elastin content using MRI with a gadolinium-based elastin-specific magnetic resonance contrast agent in Fbn1(C1039G/+) mice.. Ascending aorta elastin content was measured in 32-week-old Fbn1(C1039G/+) mice and wild-type (n=9 and n=10, respectively) using 7-T MRI with a T1 mapping sequence. Significantly lower enhancement (ie, lower R1 values, where R1=1/T1) was detected post-elastin-specific magnetic resonance contrast agent in Fbn1(C1039G/+) compared with wild-type ascending aortas (1.15±0.07 versus 1.36±0.05; P<0.05). Post-elastin-specific magnetic resonance contrast agent R1 values correlated with ascending aortic wall gadolinium content directly measured by inductively coupled mass spectroscopy (P=0.006).. Herein, we demonstrate that MRI with elastin-specific magnetic resonance contrast agent accurately measures elastin bound gadolinium within the aortic wall and detects a decrease in aortic wall elastin in Marfan mice compared with wild-type controls. This approach has translational potential for noninvasively assessing aneurysm tissue changes and risk, as well as monitoring elastin content in response to therapeutic interventions.

Topics: Animals; Aorta, Thoracic; Aortic Aneurysm, Thoracic; Aortic Dissection; Chelating Agents; Contrast Media; Disease Models, Animal; Elastin; Feasibility Studies; Heterocyclic Compounds, 1-Ring; Magnetic Resonance Imaging; Male; Marfan Syndrome; Mice; Mice, Inbred C57BL; Reproducibility of Results

Pulmonary vascular remodeling, the pathological hallmark of pulmonary arterial hypertension, is attributed to proliferation, apoptosis resistance, and migration of vascular cells. A role of dysregulated matrix cross-linking and stability as a pathogenic mechanism has received little attention. We aimed to assess whether matrix cross-linking enzymes played a causal role in experimental pulmonary hypertension (PH).. All 5 lysyl oxidases were detected in concentric and plexiform vascular lesions of patients with idiopathic pulmonary arterial hypertension. Lox, LoxL1, LoxL2, and LoxL4 expression was elevated in lungs of patients with idiopathic pulmonary arterial hypertension, whereas LoxL2 and LoxL3 expression was elevated in laser-capture microdissected vascular lesions. Lox expression was hypoxia-responsive in pulmonary artery smooth muscle cells and adventitial fibroblasts, whereas LoxL1 and LoxL2 expression was hypoxia-responsive in adventitial fibroblasts. Lox expression was increased in lungs from hypoxia-exposed mice and in lungs and pulmonary artery smooth muscle cells of monocrotaline-treated rats, which developed PH. Pulmonary hypertensive mice exhibited increased muscularization and perturbed matrix structures in vessel walls of small pulmonary arteries. Hypoxia exposure led to increased collagen cross-linking, by dihydroxylysinonorleucine and hydroxylysinonorleucine cross-links. Administration of the lysyl oxidase inhibitor β-aminopropionitrile attenuated the effect of hypoxia, limiting perturbations to right ventricular systolic pressure, right ventricular hypertrophy, and vessel muscularization and normalizing collagen cross-linking and vessel matrix architecture.. Lysyl oxidases are dysregulated in clinical and experimental PH. Lysyl oxidases play a causal role in experimental PH and represent a candidate therapeutic target. Our proof-of-principle study demonstrated that modulation of lung matrix cross-linking can affect pulmonary vascular remodeling associated with PH.

Topics: Adult; Aged, 80 and over; Animals; Antihypertensive Agents; Case-Control Studies; Cell Hypoxia; Cells, Cultured; Collagen; Disease Models, Animal; Elastin; Enzyme Inhibitors; Familial Primary Pulmonary Hypertension; Female; Fibroblasts; Gene Expression Regulation, Enzymologic; Humans; Hypertension, Pulmonary; Hypertrophy, Right Ventricular; Hypoxia; Isoenzymes; Male; Mice; Middle Aged; Monocrotaline; Muscle, Smooth, Vascular; Myocytes, Smooth Muscle; Protein-Lysine 6-Oxidase; Pulmonary Artery; Rats; RNA, Messenger; Ventricular Dysfunction, Right; Young Adult

This study investigated the effects of hypertension on regional aortic biomechanical and structural properties in three rat models of vascular calcification: the hypertensive Lewis polycystic kidney (LPK; n = 13) model of chronic kidney disease, spontaneously hypertensive rats (SHRs; n = 12), and calcification in normotensive Lewis rats induced by vitamin D3 and nicotine (VDN; n = 8). Lewis and Wistar-Kyoto rats were controls. Thoracic and abdominal aortic stiffness parameters were assessed by tensile testing. In models where aortic stiffness differences compared with controls existed in both thoracic and abdominal segments, an additional cohort was quantified by histology for thoracic and abdominal aortic elastin, collagen, and calcification. LPK and VDN animals had higher thoracic breaking strain than control animals (P < 0.01 and P < 0.05, respectively) and lower energy absorption within the tensile curve of the abdominal aorta (P < 0.05). SHRs had a lower abdominal breaking stress than Wistar-Kyoto rats. LPK and VDN rats had more elastic lamellae fractures than control rats (P < 0.001), which were associated with calcium deposition (thoracic R = 0.37, P = 0.048; abdominal: R = 0.40, P = 0.046). LPK rats had higher nuclear density than control rats (P < 0.01), which was also evident in the thoracic but not abdominal aorta of VDN rats (P < 0.01). In LPK and VDN rats, but not in control rats, media thickness and cross-sectional area were at least 1.5-fold greater in thoracic than abdominal regions. The calcification models chronic kidney disease and induced calcification in normotension caused differences in regional aortic stiffness not seen in a genetic form of hypertension. Detrimental abdominal aortic remodeling but lower stiffness in the thoracic aorta with disease indicates possible compensatory mechanisms in the proximal aorta.

Topics: Animals; Aorta, Abdominal; Aorta, Thoracic; Biomechanical Phenomena; Cholecalciferol; Collagen; Disease Models, Animal; Elastin; Female; Hemodynamics; Hypertension; Male; Oxazines; Rats; Rats, Inbred Lew; Rats, Inbred SHR; Rats, Inbred WKY; Renal Insufficiency, Chronic; Tensile Strength; Vascular Calcification; Vascular Stiffness

The incidence of abdominal aortic aneurysms (AAAs) has increased during the last decades. However, there is still controversy about the management of medium-sized AAAs. Therefore, novel biomarkers, besides aneurysmal diameter, are needed to assess aortic wall integrity and risk of rupture. Elastin is the key protein for maintaining aortic wall tensile strength and stability. The progressive breakdown of structural proteins, in particular, medial elastin, is responsible for the inability of the aortic wall to withstand intraluminal hemodynamic forces. Here, we evaluate the usefulness of elastin-specific molecular MRI for the in vivo characterization of AAAs.. To induce AAAs, ApoE(-/-) mice were infused with angiotensin-II. An elastin-specific magnetic resonance molecular imaging agent (ESMA) was administered after 1, 2, 3, and 4 weeks of angiotensin-II infusion to assess elastin composition of the aorta (n=8 per group). The high signal provided by ESMA allowed for imaging with high spatial resolution, resulting in an accurate assessment of ruptured elastic laminae and the compensatory expression of elastic fibers. In vivo contrast-to-noise ratios and R1-relaxation rates after ESMA administration were in good agreement with ex vivo histomorphometry (Elastica van Gieson stain) and gadolinium concentrations determined by inductively coupled plasma mass spectroscopy. Electron microscopy confirmed colocalization of ESMA with elastic fibers.. Changes in elastin content could be readily delineated and quantified at different stages of AAAs by elastin-specific molecular magnetic resonance imaging. ESMA-MRI offers potential for the noninvasive detection of the aortic rupture site prior to dilation of the aorta and the subsequent in vivo monitoring of compensatory repair processes during the progression of AAAs.

Topics: Animals; Aorta, Abdominal; Aortic Aneurysm, Abdominal; Disease Models, Animal; Elasticity; Elastin; Magnetic Resonance Imaging; Male; Mass Spectrometry; Mice; Mice, Inbred C57BL; Microscopy, Electron; Molecular Imaging

Remodeling in chronic obstructive pulmonary disease (COPD) has at least two dimensions: small airway wall thickening and destruction of alveolar walls. Recently we showed comparable alterations of the extracellular matrix (ECM) compounds collagen, hyaluoran, and elastin in alveolar and small airway walls of COPD patients. The aim of this study was to characterize and assess similarities in alveolar and small airway wall matrix remodeling in chronic COPD models. From this comparative characterization of matrix remodeling we derived and elaborated underlying mechanisms to the matrix changes reported in COPD. Lung tissue sections of chronic models for COPD, either induced by exposure to cigarette smoke, chronic intratracheal lipopolysaccharide instillation, or local tumor necrosis factor (TNF) expression [surfactant protein C (SPC)-TNFα mice], were stained for elastin, collagen, and hyaluronan. Furthermore TNF-α matrix metalloproteinase (MMP)-2, -9, and -12 mRNA expression was analyzed using qPCR and localized using immunohistochemistry. Both collagen and hyaluronan were increased in alveolar and small airway walls of all three models. Interestingly, elastin contents were differentially affected, with a decrease in both alveolar and airway walls in SPC-TNFα mice. Furthermore TNF-α and MMP-2 and -9 mRNA and protein levels were found to be increased in alveolar walls and around airway walls only in SPC-TNFα mice. We show that only SPC-TNFα mice show changes in elastin remodeling that are comparable to what has been observed in COPD patients. This reveals that the SPC-TNFα model is a suitable model to study processes underlying matrix remodeling and in particular elastin breakdown as seen in COPD. Furthermore we indicate a possible role for MMP-2 and MMP-9 in the breakdown of elastin in airways and alveoli of SPC-TNFα mice.

Topics: Airway Remodeling; Animals; Disease Models, Animal; Elastin; Extracellular Matrix; Fibrillar Collagens; Gene Expression; Hyaluronic Acid; Lipopolysaccharides; Male; Matrix Metalloproteinase 2; Matrix Metalloproteinase 9; Mice; Mice, Inbred C57BL; Pulmonary Alveoli; Pulmonary Disease, Chronic Obstructive; Smoking; Tumor Necrosis Factor-alpha

Unique innate immunity-linked γδT cells have been seen in early human artery lesions, but their role in lesion development has received little attention. Here we investigated whether γδT cells modulate atherogenesis in apolipoprotein E-deficient (ApoE KO) mice. We found that γδT cell numbers were markedly increased in the proximal aorta of ApoE-deficient vs. wild-type mice during early atherogenesis, particularly in the aortic root and arch, where they comprised most of the T cells and lesion progression is most rapid. γδT cells infiltrated intimal lesions in ApoE KO mice, but only the adventitia in wild-type mice, and were more prevalent than CD4+ T cells in early nascent lesions, as evaluated by en face confocal microscopy. These aortic γδT cells produced IL-17, but not IFN-γ, analyzed by ex vivo FACS. Furthermore, aortic arch lipid accumulation correlated strongly with abundance of IL-17-expressing splenic γδT cells in individual ApoE KO mice. To investigate the role of these γδT cells in early atherogenesis, we analyzed ApoE/γδT double knockout (DKO) compared to ApoE KO mice. We observed reduced early intimal lipid accumulation at sites of nascent lesion formation, both in chow-fed (by 40%) and Western diet-fed (by 44%) ApoE/γδT DKO mice. In addition, circulating neutrophils were drastically reduced in these DKO mice on Western diet, while expansion of inflammatory monocytes and splenic Th1 or Th17 lymphocytes was not affected. These data reveal, for the first time, a pathogenic role of γδT cells in early atherogenesis in ApoE KO mice, by mechanisms likely to involve their IL-17 production and induction of neutrophilia. Targeting γδT cells thus might offer therapeutic benefit in atherosclerosis or other inflammatory vascular diseases.

Topics: Animals; Antigens, CD; Antigens, Differentiation, Myelomonocytic; Aorta; Aorta, Thoracic; Apolipoproteins E; Atherosclerosis; Diet, High-Fat; Disease Models, Animal; Disease Progression; Elastin; Hypercholesterolemia; Interleukin-17; Leukocyte Disorders; Lipids; Male; Mice; Mice, Knockout; Receptors, Antigen, T-Cell, gamma-delta; Spleen; T-Lymphocytes; Th17 Cells

Persistent pulmonary hypertension of the newborn (PPHN) is a clinical syndrome that is characterized by high pulmonary vascular resistance due to changes in lung vascular growth, structure, and tone. PPHN has been primarily considered as a disease of the small pulmonary arteries (PA), but proximal vascular stiffness has been shown to be an important predictor of morbidity and mortality in other diseases associated with pulmonary hypertension (PH). The objective of this study is to characterize main PA (MPA) stiffness in experimental PPHN and to determine the relationship of altered biomechanics of the MPA with changes in extracellular matrix (ECM) content and orientation of collagen and elastin fibers. MPAs were isolated from control and PPHN fetal sheep model and were tested by planar biaxial testing to measure stiffness in circumferential and axial vessel orientations. Test specimens were fixed for histological assessments of the vascular wall ECM constituents collagen and elastin. MPAs from PPHN sheep had increased mechanical stiffness (P < 0.05) and altered ECM remodeling compared with control MPA. A constitutive mathematical model and histology demonstrated that PPHN vessels have a smaller contribution of elastin and a greater role for collagen fiber engagement compared with the control arteries. We conclude that exposure to chronic hemodynamic stress in late-gestation fetal sheep increases proximal PA stiffness and alters ECM remodeling. We speculate that proximal PA stiffness further contributes to increased right ventricular impedance in experimental PPHN, which contributes to abnormal transition of the pulmonary circulation at birth.

Topics: Adventitia; Animals; Collagen; Disease Models, Animal; Elastin; Embryo, Mammalian; Extracellular Matrix; Hemodynamics; Humans; Infant, Newborn; Lung; Persistent Fetal Circulation Syndrome; Pulmonary Artery; Pulmonary Circulation; Sheep; Vascular Resistance; Vascular Stiffness

The progression of abdominal aortic aneurysm (AAA) involves a sustained influx of proinflammatory macrophages, which exacerbate tissue injury by releasing cytokines, chemokines, and matrix metalloproteinases. Previously, we showed that Notch deficiency reduces the development of AAA in the angiotensin II-induced mouse model by preventing infiltration of macrophages. Here, we examined whether Notch inhibition in this mouse model prevents progression of small AAA and whether these effects are associated with altered macrophage differentiation.. Treatment with pharmacological Notch inhibitor (DAPT [N-(N-[3,5-difluorophenacetyl]-L-alanyl)-S-phenylglycine t-butyl ester]) at day 3 or 8 of angiotensin II infusion arrested the progression of AAA in Apoe(-/-) mice, as demonstrated by a decreased luminal diameter and aortic width. The abdominal aortas of Apoe(-/-) mice treated with DAPT showed decreased expression of matrix metalloproteinases and presence of elastin precursors including tropoelastin and hyaluronic acid. Marginal adventitial thickening observed in the aorta of DAPT-treated Apoe(-/-) mice was not associated with increased macrophage content, as observed in the mice treated with angiotensin II alone. Instead, DAPT-treated abdominal aortas showed increased expression of Cd206-positive M2 macrophages and decreased expression of Il12-positive M1 macrophages. Notch1 deficiency promoted M2 differentiation of macrophages by upregulating transforming growth factor β2 in bone marrow-derived macrophages at basal levels and in response to IL4. Protein expression of transforming growth factor β2 and its downstream effector pSmad2 also increased in DAPT-treated Apoe(-/-) mice, indicating a potential link between Notch and transforming growth factor β2 signaling in the M2 differentiation of macrophages.. Pharmacological inhibitor of Notch signaling prevents the progression of AAA by macrophage differentiation-dependent mechanisms. The study also provides insights for novel therapeutic strategies to prevent the progression of small AAA.

Topics: Aged; Angiotensin II; Animals; Aorta, Abdominal; Aortic Aneurysm, Abdominal; Apolipoproteins E; Cell Differentiation; Cells, Cultured; Collagen; Dipeptides; Disease Models, Animal; Disease Progression; Elastin; Gene Expression Regulation; Humans; Macrophages; Male; Matrix Metalloproteinases; Mice, Knockout; Middle Aged; Receptor, Notch1; Signal Transduction; Time Factors; Transforming Growth Factor beta2

Coronary artery damage from Kawasaki disease (KD) is closely linked to the dysfunction of the endothelial progenitor cells (EPCs). The aim of the present study was to evaluate the modulatory effect of granulocyte colony-stimulating factor (G-CSF) on EPCs and elastin breakdown of coronary arteries in a KD mouse model.. A Lactobacillus casei cell wall extract (LCWE)-induced KD model was established in C57BL/6 mice that were subsequently administrated with recombinant human G-CSF (rhG-CSF). Nω-nitro-L-arginine methyl ester (L-NAME) was administrated for the negative intervention. Evaluations included coronary artery lesions, EPC number and functions, and the plasma concentration of nitric oxide (NO).. Elastin breakdown was found in the coronary arteries of model mice 56 days after injection of LCWE. The number of circulating EPCs, plasma concentration of NO, and functions of bone marrow EPCs, including proliferation, adhesion, and migration abilities, were all lower in the KD model group compared with those in the control group. After administration of rhG-CSF, the number of circulating EPCs and plasma concentration of NO were increased significantly compared with those in the KD model group. There were also increases in the functional indexes of EPCs. Furthermore, rhG-CSF administration improved the elastin breakdown effectively. However, these protective effects of rhG-CSF on coronary arteries were attenuated by L-NAME.. The present study indicated that the administration of G-CSF prevents elastin breakdown of the coronary arteries by enhancing the number and functions of EPCs via the NO system, and then accelerates the repair of coronary artery lesions in the KD.

Topics: Animals; Coronary Vessels; Disease Models, Animal; Elastin; Endothelial Progenitor Cells; Granulocyte Colony-Stimulating Factor; Male; Mice; Mice, Inbred C57BL; Mucocutaneous Lymph Node Syndrome; NG-Nitroarginine Methyl Ester; Nitrogen Oxides

One potential mechanism through which obesity exerts adverse effects on the vascular system is by increasing aortic stiffness, a change known to be predictive of increased cardiovascular mortality. The aim of this study was to investigate the pathophysiology that links obesity to aortic stiffening.. Obese (ob/ob) mice were used to examine physical, morphological, and molecular changes in the aorta in response to obesity. ob/ob mice had increased aortic pulse wave velocity and tissue rigidity. ob/ob aorta exhibited decreases of lysyl oxidase (LOX) activity and cross-linked elastin, and increases of elastin fragmentation and elastolytic activity. The aortas of ob/ob mice were surrounded by a significant amount of proinflammatory and pro-oxidative perivascular adipose tissue. In vitro studies revealed that the conditioned medium from differentiated adipocytes or the perivascular adipose tissue of ob/ob mice attenuated LOX activity. Furthermore, inhibition of LOX in wild-type lean mice caused elastin fragmentation and induced a significant increase in pulse wave velocity. Finally, we found that obese humans had stiffer arteries and lower serum LOX levels than do normal-weight humans.. Our results demonstrated that obesity resulted in aortic stiffening in both humans and mice, and established a causal relationship between LOX downregulation and aortic stiffening in obesity.

Topics: Adipocytes; Adipose Tissue; Adult; Aminopropionitrile; Animals; Aorta, Abdominal; Case-Control Studies; Cell Line; Culture Media, Conditioned; Cytokines; Disease Models, Animal; Dose-Response Relationship, Drug; Down-Regulation; Elastic Modulus; Elastin; Enzyme Inhibitors; Female; Humans; Inflammation Mediators; Male; Mice; Mice, Inbred C57BL; Middle Aged; Obesity; Oxidative Stress; Protein-Lysine 6-Oxidase; Pulse Wave Analysis; Time Factors; Vascular Stiffness

Hypertension is accompanied by structural remodelling of vascular extracellular matrix (ECM). Tissue inhibitor of metalloproteinases (TIMPs) inhibits matrix metalloproteinases (MMPs) that degrade the matrix structural proteins. In response to a hypertensive stimulus, the balance between MMPs and TIMPs is altered. We examined the role of TIMPs in agonist-induced hypertension.. We subjected TIMP-knockout mice to angiotensin II (Ang II) infusion, and found that Ang-II-induced hypertension in TIMP1(-/-), TIMP2(-/-), and TIMP4(-/-) mice was comparable to wild-type (WT) mice, but significantly suppressed in TIMP3(-/-) mice. Ex vivo pressure myography analyses on carotid and mesenteric arteries revealed that Ang-II-infused TIMP3(-/-) arteries were more distensible with impaired elastic recoil compared with the WT group. The acute response to vasoconstriction and vasodilation was intact in TIMP3(-/-) mesenteric and carotid arteries. Mesenteric arteries from TIMP3(-/-)-Ang II mice exhibited a reduced media-to-lumen ratio, suppressed collagen and elastin levels, elevated elastase and gelatinase proteolytic activities compared with WT-Ang II. TIMP3(-/-)-Ang II carotid arteries also showed adverse structural remodelling. Treatment of mice with doxycycline, a matrix metalloproteinase inhibitor, improved matrix integrity in mesenteric and carotid arteries in TIMP3(-/-)-Ang II and differentially regulated elastin and collagen levels in WT-Ang II vs. TIMP3(-/-)-Ang II.. Our study demonstrates a critical role for TIMP3, among all TIMPs, is preserving arterial ECM in response to Ang II. It is critical to acknowledge that the suppressed Ang-II-induced hypertension in TIMP3(-/-) mice is not a protective mechanism but owing to adverse remodelling in arterial matrix.

Topics: Angiotensin II; Animals; Arterial Pressure; Carotid Arteries; Collagen; Disease Models, Animal; Elastin; Gelatinases; Hypertension; Matrix Metalloproteinase Inhibitors; Mesenteric Arteries; Mice; Mice, Inbred C57BL; Mice, Knockout; Time Factors; Tissue Inhibitor of Metalloproteinase-1; Tissue Inhibitor of Metalloproteinase-2; Tissue Inhibitor of Metalloproteinase-3; Tissue Inhibitor of Metalloproteinase-4; Tissue Inhibitor of Metalloproteinases; Vasoconstriction; Vasodilation

Elevated plasma aldosterone concentrations in patients have been linked to a spectrum of cardiovascular diseases. Mineralocorticoid receptor antagonists provide additional benefits in patients with heart failure. However, whether aldosterone and the mineralocorticoid receptor are involved in aortic aneurysm is unknown.. We report that administration of deoxycorticosterone acetate (DOCA) and salt or aldosterone and salt, but not DOCA or salt alone, to C57BL/6 male mice induced abdominal and thoracic aortic aneurysm formation and rupture in an age-dependent manner. DOCA and salt- or aldosterone and salt-induced aortic aneurysm mimicked human aortic aneurysm with respect to elastin degradation, inflammatory cell infiltration, smooth muscle cell degeneration and apoptosis, and oxidative stress. Aortic aneurysm formation did not correlate with the increase in blood pressure induced by DOCA and salt. Systemic administration of the angiotensin-converting enzyme inhibitor, enalapril, or angiotensin type 1 receptor antagonist, losartan, did not affect DOCA and salt-induced aortic aneurysm. In contrast, the mineralocorticoid receptor antagonists, spironolactone or eplerenone, significantly attenuated DOCA and salt- or aldosterone and salt-induced aortic aneurysm.. The current study describes a novel aortic aneurysm animal model induced by mineralocorticoid receptor agonist and high salt, and reveals a previously unrecognized but potentially significant role of aldosterone in the pathogenesis of aortic aneurysm. These findings imply that mineralocorticoid receptor antagonists may be effective in the treatment of some aortic aneurysms.

Topics: Aldosterone; Angiotensin II Type 1 Receptor Blockers; Angiotensin-Converting Enzyme Inhibitors; Animals; Aorta; Aortic Aneurysm, Abdominal; Aortic Aneurysm, Thoracic; Aortic Rupture; Apoptosis; Blood Pressure; Desoxycorticosterone; Disease Models, Animal; Elastin; Enalapril; Eplerenone; Losartan; Male; Mice; Mice, Inbred C57BL; Mineralocorticoid Receptor Antagonists; Muscle, Smooth, Vascular; Oxidative Stress; Receptors, Mineralocorticoid; Sodium Chloride, Dietary; Spironolactone; Time Factors

Bronchopulmonary dysplasia (BPD) is one of the most common complications after preterm birth and is associated with intrauterine exposure to bacteria. Transforming growth factor-β (TGFβ) is implicated in the development of BPD.. We hypothesized that different and/or multiple bacterial signals could elicit divergent TGFβ signaling responses in the developing lung.. Time-mated pregnant Merino ewes received an intra-amniotic injection of lipopolysaccharide (LPS) and/or Ureaplasma parvum serovar 3 (UP) at 117 days' and/or 121/122 days' gestational age (GA). Controls received an equivalent injection of saline and or media. Lambs were euthanized at 124 days' GA (term = 150 days' GA). TGFβ1, TGFβ2, TGFβ3, TGFβ receptor (R)1 and TGFβR2 protein levels, Smad2 phosphorylation and elastin deposition were evaluated in lung tissue.. Total TGFβ1 and TGFβ2 decreased by 24 and 51% after combined UP+LPS exposure, whereas total TGFβ1 increased by 31% after 7 days' LPS exposure but not after double exposures. Alveolar expression of TGFβR2 decreased 75% after UP, but remained unaltered after double exposures. Decreased focal elastin deposition after single LPS exposure was prevented by double exposures.. TGFβ signaling components and elastin responded differently to intrauterine LPS and UP exposure. Multiple bacterial exposures attenuated TGFβ signaling and normalized elastin deposition.

Topics: Amnion; Animals; Chorioamnionitis; Disease Models, Animal; Elastin; Female; Gestational Age; Inflammation; Lipopolysaccharides; Lung; Phosphorylation; Pregnancy; Pregnancy Complications; Receptors, Transforming Growth Factor beta; Sheep; Signal Transduction; Smad2 Protein; Transforming Growth Factor beta; Transforming Growth Factor beta1; Transforming Growth Factor beta2; Transforming Growth Factor beta3; Ureaplasma

The purpose of this study was to introduce a novel, simple and effective technique for creating a reliable rabbit model of abdominal aortic aneurysm (AAA) via a combination of periaortic calcium chloride (CaCl2) and elastase incubation.. Forty-eight New Zealand white rabbits were divided into four groups. The AAA model was developed via a 20-minute periaortic incubation of CaCl2 (0.5 mol/L) and elastase (1 Unit/µL) in a 1.5-cm aortic segment (Group CE). A single incubation of CaCl2 (Group C) or elastase (Group E) and a sham operation group (Sham Group) were used for the controls. Diameter was measured by serial digital subtraction angiography imaging on days 5, 15 and 30. Animals were sacrificed on day 5 and day 30 for histopathological and immunohistochemical studies.. All animals in Group CE developed aneurysm, with an average dilation ratio of 65.3% ± 8.9% on day 5, 86.5% ± 28.7% on day 15 and 203.6% ± 39.1% on day 30. No aneurysm was found in Group C, and only one aneurysm was seen on day 5 in Group E. Group CE exhibited less intima-media thickness, endothelial recovery, elastin and smooth muscle cell (SMC) content, but stronger expression of matrix metalloproteinase-2, matrix metalloproteinase-9 and RAM11 compared to the controls.. The novel rabbit model of AAA created by using a combination of periaortic CaCl2 and elastase incubation is simple and effective to perform and is valuable for elucidating AAA mechanisms and therapeutic interventions in experimental studies.

Topics: Angiography, Digital Subtraction; Animals; Aorta, Abdominal; Aortic Aneurysm, Abdominal; Calcium Chloride; Carotid Intima-Media Thickness; Disease Models, Animal; Elastin; Humans; Intubation; Matrix Metalloproteinase 2; Matrix Metalloproteinase 9; Pancreatic Elastase; Rabbits

Bipolar energy ligation of vessels in surgery is common. Although rare, serious failures occur. Atherosclerosis may contribute to seal failures by altering vascular compressibility and collagen content; however, no data exist.. Femoral and iliac arteries of six Yucatan swine with an identified genetic locus predisposing them to atherosclerosis were denuded with a Fogarty catheter. Animals were fed a high-fat diet for 28 wk. A Yorkshire pig was used as a normal control and fed a standard diet. At 28 wk, arteries were measured for their diameters, sealed, and divided in vivo with LigaSure. The sealed artery sections were excised and subjected to burst pressure testing. Half of the seal distal to the aorta was kept intact for histology and collagen and elastin quantification. A multiple linear regression model was used to assess variables contributing to burst pressure. Covariates included were vessel diameter, degree of atherosclerosis, and collagen content.. Experimental animals were hypercholesterolemic. Atherosclerosis occurred in 90% of seals in induced animals, with severe atherosclerosis in 62% of seals. There was site-selective deposition of atherosclerotic plaques in larger diameter iliac vessels. A model including collagen and size best predicted burst pressure. Every 10-U increase in collagen resulted in 15% increase in burst pressure (95% confidence interval = 0.2%-32%, P = 0.047, R(2) = 0.36). Atherosclerosis was unrelated to burst pressure controlling for collagen and size.. Collagen and size provide the best model fit for predicting burst pressure. Quantitative research in human vasculature is warranted to better understand the influence of atherosclerosis and collagen content on seal failures.

Topics: Animals; Atherosclerosis; Balloon Embolectomy; Collagen; Disease Models, Animal; Elastin; Female; Femoral Artery; Hemostatic Techniques; Hypercholesterolemia; Iliac Artery; Plaque, Atherosclerotic; Swine; Swine, Miniature; Vascular Surgical Procedures

Abdominal aortic aneurysm (AAA) is a life-threatening disease affecting almost 10% of the population over the age of 65. Nitrogen-containing bisphosphonates (N-BPs) have been shown to exert anti-atherogenic and anti-angiogenic effects, but the potential effects of N-BPs on AAA remain unclear. Here, we tested whether a potent N-BP, zoledronate, can attenuate the formation of Angiotensin II (Ang II)-induced AAA in hyperlipidaemic mice.. Low-density lipoprotein receptor(-/-) (LDLR(-/-)) mice infused for 28 days with Ang II were treated with placebo and 100 μg/kg/day zoledronate. Continuous Ang II infusion in LDLR(-/-) mice exhibited a 59% incidence of AAA formation, and treatment with zoledronate decreased AAA formation (21%). Compared with the saline group, administration of zoledronate in Ang II-infused LDLR(-/-) mice attenuated the expansion of the suprarenal aorta (maximal aortic diameter), reduced elastin degradation in the media layer of the aorta, and significantly diminished vascular inflammation by reduction in vascular cell adhesion molecule expression and macrophage accumulation. Treatment with zoledronate decreased matrix metalloproteinase-2 (MMP-2) in aortic tissues. Zoledronate-treated mice had significant down-regulation of JNK, NF-κB, and reduced Ang II-induced Rho/ROCK activation. Zoledronate reduced monocytes adherence to human aortic endothelial cells in vitro.. Zoledronate-attenuated Ang II induced AAA formation by suppression of MMP-2 activity and suppressed vascular inflammation and Ang II-induced Rho/ROCK activities.

Topics: Angiotensin II; Animals; Anti-Inflammatory Agents; Aorta, Abdominal; Aortic Aneurysm, Abdominal; Cell Adhesion; Cell Line; Coculture Techniques; Dilatation, Pathologic; Diphosphonates; Disease Models, Animal; Dose-Response Relationship, Drug; Elastin; Endothelial Cells; Enzyme Activation; Humans; Imidazoles; JNK Mitogen-Activated Protein Kinases; Macrophages; Male; Matrix Metalloproteinase 2; Mice; Mice, Inbred C57BL; Mice, Knockout; Monocytes; NF-kappa B; Phosphorylation; Receptors, LDL; rho GTP-Binding Proteins; rho-Associated Kinases; rhoA GTP-Binding Protein; Signal Transduction; Vascular Cell Adhesion Molecule-1; Zoledronic Acid

Elastase incubation was performed in the LCCA in 13 New Zealand white rabbits. Three weeks after incubation, DSA demonstrated that 10 (10/13, 77%) bifurcation-type aneurysms at the origin of the LCCA were present; mean aneurysm neck, width, and height values were 3.7 ± 1.1, 3.8 ± 0.9, and 8.7 ± 2.3 mm, respectively. The LCCA can be used to create bifurcation aneurysms in rabbits.

Topics: Aneurysm; Angiography, Digital Subtraction; Animals; Aorta, Thoracic; Aortic Aneurysm, Thoracic; Carotid Artery Diseases; Carotid Artery, Common; Disease Models, Animal; Elastin; Ligation; Rabbits

Hypoplastic left heart syndrome (HLHS) is one of the most common severe congenital cardiac anomalies, characterized by a marked hypoplasia of left-sided structures of the heart, which is commonly accompanied by a thick layer of fibroelastic tissue, termed endocardial fibroelastosis (EFE). Because human EFE develops only in fetal or neonatal hearts, and often in association with reduced blood flow, we sought to mimic these conditions by subjecting neonatal and 2-wk-old rat hearts to variations of the heterotopically transplanted heart model with either no intracavitary or normal flow and compare endocardium with human EFE tissue.. Hearts obtained from neonatal and 2-wk-old rats were heterotopically transplanted in young adult Lewis rats in a working (loaded) or nonworking (unloaded) mode. After 2-wk survival, hearts were explanted for histologic analysis by staining for collagen, elastin, and cellular elements. These sections were compared with human EFE tissue from HLHS.. EFE, consisting of collagen and elastin with scarce cellular and vascular components, developed only in neonatal unloaded transplanted hearts and displayed the same histopathologic findings as EFE from patients with HLHS. Loaded hearts and 2-wk-old hearts did not show these alterations.. This animal model for EFE will serve as a tool to study the mechanisms of EFE formation, such as fluid forces, in HLHS in a systematic manner. A better understanding of the underlying cause of the EFE formation in HLHS will help to develop novel treatment strategies to better preserve growth of the hypoplastic left ventricle.

Topics: Animals; Animals, Newborn; Collagen; Disease Models, Animal; Elastin; Endocardial Fibroelastosis; Heart Transplantation; Hemodynamics; Humans; Hypoplastic Left Heart Syndrome; Rats; Rats, Inbred Lew; Transplantation, Heterotopic

Marfan syndrome (MFS) is an inherited disorder of connective tissue caused by mutations in the gene for fibrillin-1 (FBN1). The complex pathogenesis of MFS involves changes in transforming growth factor beta (TGF-β) signaling and increased matrix metalloproteinase (MMP) expression. Fibrillin-1 and elastin have repeated Gly-x-x- Pro-Gly (GxxPG) motifs that can induce a number of effects including macrophage chemotaxis and increased MMP activity by induction of signaling through the elastin-binding protein (EBP). In this work, we test the hypothesis that antagonism of GxxPG fragments can suppress disease progression in the Marfan aorta. Fibrillin-1 underexpressing mgR/mgR Marfan mice were treated with weekly intraperitoneal (i.p.) injections of an antibody directed against GxxPG fragments. The treatment was started at 3 weeks of age and continued for 8 weeks. The treatment significantly reduced MMP-2, MMP-9 and pSmad2 activity, as well as fragmentation and macrophage infiltration in the aorta of the mgR/mgR mice. Additionally, airspace enlargement and increased pSmad2 activity in the lungs of mgR/mgR animals were prevented by the treatment. Our findings demonstrate the important role of secondary cellular events caused by GxxPG-containing fragments and matrix-induced inflammatory activity in the pathogenesis of thoracic aortic aneurysm (TAA) in mgR/mgR mice. Moreover, the results of the current study suggest that antagonism of the effects of GxxPG fragments may be a fruitful therapeutic strategy in MFS.

Topics: Amino Acid Motifs; Animals; Antibodies, Monoclonal; Aortic Aneurysm, Thoracic; Aortic Diseases; Blotting, Western; Disease Models, Animal; Elastin; Enzyme-Linked Immunosorbent Assay; Fibrillin-1; Fibrillins; Immunohistochemistry; Latent TGF-beta Binding Proteins; Macrophages; Marfan Syndrome; Matrix Metalloproteinase 2; Matrix Metalloproteinase 9; Mice; Microfilament Proteins; Mutation; Peptides; Signal Transduction; Smad2 Protein; Transforming Growth Factor beta; Up-Regulation

Fetal intrauterine growth restriction (IUGR) results in increased placental resistance to blood flow, fetal hypertension, and increased pulsatility stresses shown to lead to vascular remodeling. We tested our hypothesis that IUGR causes decreased compliance in the carotid and umbilical arteries due to altered extracellular matrix (ECM) composition and structure.. A sheep model of placental insufficiency-induced IUGR (PI-IUGR) was created by exposure of the pregnant ewe to elevated ambient temperatures. Umbilical and carotid arteries from near-term fetuses were tested with pressure-diameter measurements to compare passive compliance in control and PI-IUGR tissues. ECM composition was measured via biochemical assay, and the organization was determined by using histology and second-harmonic generation imaging.. We found that PI-IUGR increased arterial stiffness with increased collagen engagement, or transition stretch. PI-IUGR carotid arteries exhibited increased collagen and elastin quantity, and PI-IUGR umbilical arteries exhibited increased sulfated glycosaminoglycans. Histomorphology showed altered collagen-to-elastin ratios with altered cellular proliferation. Increased stiffness indicates altered collagen-to-elastin ratios with less elastin contribution leading to increased collagen engagement.. Because vessel stiffness is a significant predictor in the development of hypertension, disrupted ECM deposition in IUGR provides a potential link between IUGR and adult hypertension.

Topics: Animals; Carotid Arteries; Cell Proliferation; Collagen; Compliance; Disease Models, Animal; Elastin; Extracellular Matrix; Female; Fetal Growth Retardation; Gestational Age; Glycosaminoglycans; Hypertension; Male; Pregnancy; Sheep; Umbilical Arteries; Vascular Stiffness

Atherosclerotic plaque rupture is a major cause of myocardial infarction and ischemic stroke. The adhesive strength of the bond between a plaque and the vascular wall, measured as local energy release rate, G, is used for quantitative plaque stability estimation. We tested the hypothesis that adhesive strength varies with plaque composition. Matrix metalloproteinase-12 (MMP12) deficiency was previously reported to alter lesion composition. To estimate G values, peeling experiments are performed on aortic plaques from apolipoprotein E knockout (apoE KO) and apoE MMP12 double knockout (DKO) male mice after 8 months on high-fat diet. For plaques in apoE KO and apoE MMP12 DKO mice, experimental values for G differ significantly (p<0.002) between genotypes, averaging 19.2J/m(2) and 12.1J/m(2), respectively. Histology confirms that plaques delaminate along their interface with the underlying internal elastic lamina (IEL) in both genotypes. Quantitative image analysis of stained tissue sections demonstrates a significant positive correlation (p<0.05) between local collagen content of lesions and G values in both genotypes, indicating that adhesive strength of plaques depends on local collagen content. Surprisingly, macrophage content of aortic plaques is neither significantly correlated with G values nor significantly different between genotypes. The IEL underlying plaques in apoE KO mice is significantly more fragmented (number of breaks and length of breaks) than in apoE MMP12 DKO mice, suggesting that elastin fragmentation also influences adhesion strength of plaques. Overall, our results suggest that plaques adhere more strongly to the underlying IEL in apoE KO mice than in apoE MMP12 DKO mice.

Topics: Adhesiveness; Animals; Apolipoproteins E; Biomechanical Phenomena; Collagen; Diet, High-Fat; Disease Models, Animal; Elastic Tissue; Elastin; Humans; Macrophages; Male; Matrix Metalloproteinase 12; Mice; Mice, Knockout; Plaque, Atherosclerotic

Little is known about tendons and tenocyte biological behaviour during aging and, especially, oestrogen deficiency. The aim of this study was to evaluate in vitro the proliferation and metabolism of tenocytes isolated from the Achilles tendons of ovariectomised (OVX), middle-aged (OLD) and young (YOUNG) rats. An in vitro model of micro-wound healing was also used to assess age and oestrogen deficiency differences in tendon healing. In standard culture condition, OLD and OVX tenocytes showed a significantly lower proliferation rate, collagen I, aggrecan and elastin than YOUNG ones. In OVX group, fibronectin and elastin significantly decreased in comparison to YOUNG and OLD groups, respectively, whereas vascular endothelial growth factor and metalloproteinases-13 increased than those of both YOUNG and OLD groups. In the micro-wound healing model, tenocytes from both OVX and OLD showed a significantly lower healing rate, proliferation rate, collagen I and nitrix oxide in comparison to YOUNG. OVX elastin value was significantly lower than YOUNG one and OVX healing rate and cell migration speed, proliferation rate and fibronectin results were lower, whereas collagen III and metalloproteinase-13 higher in comparison to both YOUNG and OLD groups. These results highlighted how aging and, more significantly, oestrogen deficiency negatively affect tendon metabolism and healing. Our work improves the body of knowledge on the effects of senescence and oestrogen deficiency on tenocyte behaviour and allows further studies to find solution for the prevention of tendon injuries in aging and menopause.

Topics: Achilles Tendon; Aggrecans; Aging; Animals; Cell Movement; Cell Proliferation; Cells, Cultured; Collagen Type I; Disease Models, Animal; Elastin; Estrogens; Female; Follow-Up Studies; Ovariectomy; Rats; Rats, Sprague-Dawley; Tendon Injuries

A single instillation of porcine pancreatic elastase (PPE) results in significant airspace enlargement on the 28th day after instillation, whereas cigarette smoke (CS) exposure requires 6 months to produce mild emphysema in rodents. Considering that there are differences in the pathogenesis of parenchymal destruction in these different experimental models, it is likely that there may be different patterns of extracellular matrix (ECM) remodeling. To evaluate ECM remodeling, C57BL/6 mice were submitted to either a nasal drop of PPE (PPE 28 Days) or exposed for 6 months to cigarette smoke (CS 6 months). Control groups received either an intranasal instillation of saline solution (Saline 28 Days) or remained without any smoke inhalation for six months (Control 6 months). We measured the mean linear intercept and the volume proportion of collagen type I, collagen type III, elastin and fibrillin. We used emission-scanning confocal microscopy to verify the fiber distribution. Both models induced increased mean linear intercept in relation to the respective controls, being larger in the elastase model in relation to the CS model. In the CS model, emphysema was associated with an increase in the volume proportion of fibrillin, whereas in the PPE model there was an increase in the parenchymal elastin content. In both models, there was an increase in collagen type III, which was higher in the CS-exposed mice. We concluded that ECM remodeling is different in the two most used experimental models of emphysema.

Topics: Animals; Collagen Type I; Collagen Type III; Disease Models, Animal; Elastin; Emphysema; Extracellular Matrix; Fibrillins; Immunohistochemistry; Lung; Male; Mice; Mice, Inbred C57BL; Microfilament Proteins; Microscopy, Confocal; Pancreatic Elastase; Smoking; Swine

To modify the method for creating an abdominal aortic aneurysm in rabbits, and to study its performance.. A total of 24 New Zealand white rabbits were induced topically with 10 μl of porcine elastase (0, 0.1, 5 and 10 units μl(-1)) to define the optimal concentration (groups A-D). Twelve aneurysms were induced with 10 units μl(-1) of 10 μl elastase to serve as a follow-up group (group E) to serve as a follow-up. A 1.5-cm aortic segment was isolated and induced with elastase solution for 30 min.. All animals in groups D and E developed AAA by day 5. Aneurysms in Group E were stable over 100 days. Partial destruction to disappearance of elastic lamellae and smooth muscle cells (SMCs) was seen in elastase-treated animals by day 5. Regenerated elastin and proliferated SMCs were present in group E. Matrix metalloproteinases 2 and 9 and RAM11 showed strong expression in group D, but expression decreased in group E after day 15.. The rabbit AAA model induced via topical application of porcine elastase at 10 units μl(-1) for 30 min appears easy and simple, with shorter induction and more rapid aortic dilation. The model is stable over 100 days and is useful to study the formation and progress of AAAs.

Topics: Administration, Topical; Angiography, Digital Subtraction; Animals; Aorta, Abdominal; Aortic Aneurysm, Abdominal; Aortography; Biomarkers; Cell Proliferation; Dilatation, Pathologic; Disease Models, Animal; Disease Progression; Elastic Tissue; Elastin; Immunohistochemistry; Male; Matrix Metalloproteinase 2; Matrix Metalloproteinase 9; Muscle, Smooth, Vascular; Pancreatic Elastase; Rabbits; Swine; Time Factors

Abdominal aortic aneurysms (AAAs) are common, but their exact pathogenesis remains unknown and no specific medical therapies are available. We sought to evaluate interleukin-1β (IL-1β) and interleukin-1 receptor (IL-1R) in an experimental AAA model to identify novel therapeutic targets for AAA treatment.. IL-1β mRNA and protein levels were significantly elevated in abdominal aortas of 8- to 12-week-old male C57Bl/6 mice after elastase aortic perfusion (wild-type [WT]) compared with saline perfusion. Mice with genetic deletion of IL-1β (IL-1β knockout [KO]) or IL-1R (IL-1R KO) that underwent elastase perfusion demonstrated significant protection against AAA formation, with maximal aortic dilations of 38.0±5.5% for IL-1β KO and 52.5±4.6% for IL-1R KO, compared with 89.4±4.0% for WT mice (P<0.005). Correspondingly, IL-1β KO and IL-1R KO aortas had reduced macrophage and neutrophil staining with greater elastin preservation compared with WT. In WT mice pretreated with escalating doses of the IL-1R antagonist anakinra, there was a dose-dependent decrease in maximal aortic dilation (R=-0.676; P<0.0005). Increasing anakinra doses correlated with decreasing macrophage staining and elastin fragmentation. Lastly, WT mice treated with anakinra 3 or 7 days after AAA initiation with elastase demonstrated significant protection against AAA progression and had decreased aortic dilation compared with control mice.. IL-1β is critical for AAA initiation and progression, and IL-1β neutralization through genetic deletion or receptor antagonism attenuates experimental AAA formation. Disrupting IL-1β signaling offers a novel pathway for AAA treatment.

Topics: Animals; Aorta, Abdominal; Aortic Aneurysm, Abdominal; Dilatation, Pathologic; Disease Models, Animal; Dose-Response Relationship, Drug; Elastin; Gene Expression Regulation; Humans; Interleukin 1 Receptor Antagonist Protein; Interleukin-1beta; Macrophages; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Neutrophils; Pancreatic Elastase; Receptors, Interleukin-1; RNA, Messenger; Signal Transduction; Time Factors

Cathepsin K (CatK) is one of the most potent mammalian elastases. We have previously shown increased expression of CatK in human abdominal aortic aneurysm (AAA) lesions. Whether this protease participates directly in AAA formation, however, remains unknown.. Mouse experimental AAA was induced with aortic perfusion of a porcine pancreatic elastase. Using this experimental model, we demonstrated that absence of CatK prevented AAA formation in mice 14 days postperfusion. CatK deficiency significantly reduced lesion CD4(+) T-cell content, total lesion and medial cell proliferation and apoptosis, medial smooth muscle cell (SMC) loss, elastinolytic CatL and CatS expression, and elastin fragmentation, but it did not affect AAA lesion Mac-3(+) macrophage accumulation or CD31(+) microvessel numbers. In vitro studies revealed that CatK contributed importantly to CD4(+) T-cell proliferation, SMC apoptosis, and other cysteinyl cathepsin and matrix metalloproteinase expression and activities in SMCs and endothelial cells but played negligible roles in microvessel growth and monocyte migration. AAA lesions from CatK-deficient mice showed reduced elastinolytic cathepsin activities compared with those from wild-type control mice.. This study demonstrates that CatK plays an essential role in AAA formation by promoting T-cell proliferation, vascular SMC apoptosis, and elastin degradation and by affecting vascular cell protease expression and activities.

Topics: Animals; Aortic Aneurysm, Abdominal; Apoptosis; Cathepsin K; CD4-Positive T-Lymphocytes; Cell Proliferation; Disease Models, Animal; Elastin; Humans; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Myocytes, Smooth Muscle; Neovascularization, Physiologic; Pancreatic Elastase

Group X secretory PLA(2) (sPLA(2)-X) is expressed in neutrophils and plays a role in the pathogenesis of neutrophil-mediated tissue inflammation and injury. This study tested the hypothesis that sPLA(2)-X in neutrophils may contribute to the pathogenesis of abdominal aortic aneurysms (AAA) using sPLA(2)-X(-/-) mice. AAA was created by application of CaCl(2) to external surface of aorta. As a result, the aortas of sPLA(2)-X(-/-) mice had smaller diameters (percent increase from baseline; 24.8 ± 3.5% vs. 49.9 ± 9.1%, respectively; P < 0.01), a reduced grade of elastin degradation, and lower activities of elastase and gelatinase (26% and 19% lower, respectively) after CaCl(2) treatment compared with sPLA(2)-X(+/+) mice. In sPLA(2)-X(+/+) mice, immunofluorescence microscopic images showed that the immunoreactivity of sPLA(2)-X was detected only in neutrophils within aortic walls 3 days, 1, 2, and 6 wk after CaCl(2) treatment, whereas the immunoreactivity was not detected in macrophages or mast cells in aortic walls. sPLA(2)-X immunoreactivity also was colocalized in cells expressing matrix metalloproteinase (MMP)-9. Neutrophils isolated from sPLA(2)-X(-/-) mice had lower activities of elastase, gelatinase, and MMP-9 in response to stimuli compared with sPLA(2)-X(+/+) mice. The attenuated release of elastase and gelatinase from sPLA(2)-X(-/-) neutrophils was reversed by exogenous addition of mouse sPLA(2)-X protein. The adoptive transfer of sPLA(2)-X(+/+) neutrophils days 0 and 3 after CaCl(2) treatment reversed aortic diameters and elastin degradation grades in the lethally irradiated sPLA(2)-X(+/+) mice reconstituted with sPLA(2)-X(-/-) bone marrow to an extent similar to that seen in sPLA(2)-X(+/+) mice. In conclusion, sPLA(2)-X in neutrophils plays a pathogenic role in AAA in a mice model.

Topics: Adoptive Transfer; Animals; Aorta; Aortic Aneurysm, Abdominal; Bone Marrow Transplantation; Calcium Chloride; Disease Models, Animal; Elastin; Gelatinases; Group X Phospholipases A2; Male; Matrix Metalloproteinase 9; Mice; Mice, Inbred C57BL; Mice, Knockout; Microscopy, Fluorescence; Neutrophils; Pancreatic Elastase; Time Factors

Dermal templates, such as Matriderm® and Integra®, are widely used in plastic and reconstructive surgery, often as two-step procedures. A recent development is the application of thin dermal templates covered with split thickness skin grafts in one-step procedures. In this experimental study, we compare the two thin matrices Matriderm® 1 mm and Integra® Single Layer in a one-step procedure with particular focus on neodermis formation.. Matriderm® 1 mm and Integra® Dermal Regeneration Template-Single Layer (1.3 mm) were compared in a rat model. In three groups of five animals each, a full thickness wound was covered with (a) Matriderm® 1 mm and neonatal rat epidermis, (b) Integra® Single Layer and neonatal rat epidermis, or, (c) neonatal rat epidermis only (control). Histological sections 2 weeks post transplantation were analyzed with regard to take of template and epidermis, neodermal thickness, collagen deposition, vascularization, and inflammatory response.. Take of both templates was complete in all animals. The Matriderm®-based neodermis was thinner but showed a higher cell density than the Integra®-based neodermis. The other parameters were similar in both matrices.. The two templates demonstrate a comparable biological behavior early after transplantation. The only difference was found regarding neodermal thickness, probably resulting from faster degradation of Matriderm®. These preliminary data suggest that both dermal templates appear similarly suitable for transplantation in a one-step procedure.

Topics: Animals; Animals, Newborn; Chondroitin Sulfates; Collagen; Dermatologic Surgical Procedures; Disease Models, Animal; Elastin; Epidermis; Female; Follow-Up Studies; Plastic Surgery Procedures; Rats; Rats, Nude; Skin; Skin Transplantation; Skin, Artificial; Wound Healing; Wounds and Injuries

Intrauterine growth restriction (IUGR) increases the risk of respiratory compromise throughout postnatal life. However, the molecular mechanism(s) underlying the respiratory compromise in offspring following IUGR is not known. We hypothesized that IUGR following maternal food restriction (MFR) would affect extracellular matrix deposition in the lung, explaining the long-term impairment in pulmonary function in the IUGR offspring. Using a well-established rat model of MFR during gestation to produce IUGR pups, we found that at postnatal day 21, and at 9 months (9M) of age the expression and abundance of elastin and alpha smooth muscle actin (αSMA), two key extracellular matrix proteins, were increased in IUGR lungs when compared to controls (P < 0.05, n = 6), as determined by both Western and immunohistochemistry analyses. Compared to controls, the MFR group showed no significant change in pulmonary resistance at baseline, but did have significantly decreased pulmonary compliance at 9M (P < 0.05 vs. control, n = 5). In addition, MFR lungs exhibited increased responsiveness to methacholine challenge. Furthermore, exposing cultured fetal rat lung fibroblasts to serum deprivation increased the expression of elastin and elastin-related genes, which was blocked by serum albumin supplementation, suggesting protein deficiency as the predominant mechanism for increased pulmonary elastin deposition in IUGR lungs. We conclude that accompanying the changes in lung function, consistent with bronchial hyperresponsiveness, expression of the key alveolar extracellular matrix proteins elastin and αSMA increased in the IUGR lung, thus providing a potential explanation for the compromised lung function in IUGR offspring.

Topics: Actins; Animals; Animals, Newborn; Caloric Restriction; Disease Models, Animal; Elastin; Extracellular Matrix; Female; Fetal Growth Retardation; Lung; Methacholine Chloride; Pregnancy; Prenatal Nutritional Physiological Phenomena; Rats; Rats, Sprague-Dawley

Marfan syndrome (MFS) is a systemic connective tissue disorder notable for the development of aortic root aneurysms and the subsequent life-threatening complications of aortic dissection and rupture. Underlying fibrillin-1 gene mutations cause increased transforming growth factor-β (TGF-β) signaling. Although TGF-β blockade prevents aneurysms in MFS mouse models, the mechanisms through which excessive TGF-β causes aneurysms remain ill-defined.. We investigated the role of microRNA-29b (miR-29b) in aneurysm formation in MFS.. Using quantitative polymerase chain reaction, we discovered that miR-29b, a microRNA regulating apoptosis and extracellular matrix synthesis/deposition genes, is increased in the ascending aorta of Marfan (Fbn1(C1039G/+)) mice. Increased apoptosis, assessed by increased cleaved caspase-3 and caspase-9, enhanced caspase-3 activity, and decreased levels of the antiapoptotic proteins, Mcl-1 and Bcl-2, were found in the Fbn1(C1039G/+) aorta. Histological evidence of decreased and fragmented elastin was observed exclusively in the Fbn1(C1039G/+) ascending aorta in association with repressed elastin mRNA and increased matrix metalloproteinase-2 expression and activity, both targets of miR-29b. Evidence of decreased activation of nuclear factor κB, a repressor of miR-29b, and a factor suppressed by TGF-β, was also observed in Fbn1(C1039G/+) aorta. Furthermore, administration of a nuclear factor κB inhibitor increased miR-29b levels, whereas TGF-β blockade or losartan effectively decreased miR-29b levels in Fbn1(C1039G/+) mice. Finally, miR-29b blockade by locked nucleic acid antisense oligonucleotides prevented early aneurysm development, aortic wall apoptosis, and extracellular matrix deficiencies.. We identify increased miR-29b expression as key to the pathogenesis of early aneurysm development in MFS by regulating aortic wall apoptosis and extracellular matrix abnormalities.

Topics: Age Factors; Angiotensin II Type 1 Receptor Blockers; Animals; Aorta; Aortic Aneurysm; Apoptosis; Apoptosis Regulatory Proteins; Cells, Cultured; Disease Models, Animal; Elastin; Female; Fibrillin-1; Fibrillins; Genetic Therapy; Losartan; Male; Marfan Syndrome; Matrix Metalloproteinase 2; Mice; Mice, Inbred C57BL; Mice, Transgenic; Microfilament Proteins; MicroRNAs; NF-kappa B; Oligonucleotides, Antisense; Real-Time Polymerase Chain Reaction; Reverse Transcriptase Polymerase Chain Reaction; Transforming Growth Factor beta; Up-Regulation

Age-related aortic stiffness is an independent risk factor for cardiovascular diseases. Although oxidative stress is implicated in aortic stiffness, the underlying molecular mechanisms remain unelucidated. Here, we examined the source of oxidative stress in aging and its effect on smooth muscle cell (SMC) function and aortic compliance using mutant mouse models.. Pulse wave velocity, determined using Doppler, increased with age in superoxide dismutase 2 (SOD2)+/- but not in wild-type, p47phox-/- and SOD1+/- mice. Echocardiography showed impaired cardiac function in these mice. Increased collagen I expression, impaired elastic lamellae integrity, and increased medial SMC apoptosis were observed in the aortic wall of aged SOD2+/- versus wild-type (16-month-old) mice. Aortic SMCs from aged SOD2+/- mice showed increased collagen I and decreased elastin expression, increased matrix metalloproteinase-2 expression and activity, and increased sensitivity to staurosporine-induced apoptosis versus aged wild-type and young (4-month-old) SOD2+/- mice. Smooth muscle α-actin levels were increased with age in SOD2+/- versus wild-type SMCs. Aged SOD2+/- SMCs had attenuated insulin-like growth factor-1-induced Akt and Forkhead box O3a phosphorylation and prolonged tumor necrosis factor-α-induced Jun N-terminal kinase 1 activation. Aged SOD2+/- SMCs had increased mitochondrial superoxide but decreased hydrogen peroxide levels. Finally, dominant-negative Forkhead box O3a overexpression attenuated staurosporine-induced apoptosis in aged SOD2+/- SMCs.. Mitochondrial oxidative stress over a lifetime causes aortic stiffening, in part by inducing vascular wall remodeling, intrinsic changes in SMC stiffness, and aortic SMC apoptosis.

Topics: Actins; Age Factors; Aging; Animals; Aorta; Aortic Diseases; Apoptosis; Cells, Cultured; Collagen Type I; Compliance; Disease Models, Animal; Elastin; Forkhead Transcription Factors; Genotype; Hydrogen Peroxide; Insulin-Like Growth Factor I; Matrix Metalloproteinase 2; Mice; Mice, Inbred C57BL; Mice, Knockout; Mitochondria; Mitogen-Activated Protein Kinase 8; Muscle, Smooth, Vascular; Myocytes, Smooth Muscle; NADPH Oxidases; Oxidative Stress; Phenotype; Proto-Oncogene Proteins c-akt; Pulsatile Flow; Stroke Volume; Superoxide Dismutase; Superoxide Dismutase-1; Superoxides; Transfection; Ultrasonography, Doppler, Pulsed; Vasodilation; Ventricular Function, Left; Ventricular Pressure

The occurrence of PFD is closely related with elasticity, toughness, and functional changes of the connective tissue of the pelvic support tissue. This study aims to evaluate the effect of mechanical stretch on the differentiation of BMSCs with a co-culture with pelvic ligament fibroblasts. BMSCs was isolated and identified from 7 day SPF SD rats. Rat pelvic ligament fibroblasts were obtained from rat pelvic ligament. The fourth passage of fibroblasts was subjected to 10% deformation with 1 Hz, 12 h periodic one-way mechanical stretch stimulation, and the cells were then co-cultured with BMSCs. The longer co-culture and co-culture with mechanical stretch (i.e. 6 and 12 days) induced more expression of elastin, LOX, and Fibulin-5, compared to the groups without stimulation. Compared to co-culture group each, Co-culture with mechanical stretch stimulation group induced significant expression of elastin, LOX, and Fibulin-5, both in 3, 6 and 12 days co-culture groups (P < 0.05). However, there were no significant differences among 3, 6, and 12 days control groups. These results suggest that in an indirect co-culture system, pelvic ligament fibroblasts with mechanical stretch stimulation can promote BMSCs differentiation, reflecting in the increased expression of elastin, LOX, and Fibulin-5.

Topics: Adipogenesis; Animals; Bone Marrow Cells; Cell Shape; Cells, Cultured; Coculture Techniques; Disease Models, Animal; Elastin; Extracellular Matrix Proteins; Fibroblasts; Gene Expression Regulation; Ligaments; Mesenchymal Stem Cells; Microscopy, Confocal; Osteoblasts; Pelvis; Protein-Lysine 6-Oxidase; Rats; Rats, Sprague-Dawley; Recombinant Proteins; RNA, Messenger; Stress, Mechanical

Preterm birth affects 8-12% of live births and is associated with the development of elevated arterial blood pressure and aortic narrowing in later life; this suggests that preterm birth may alter the development of arteries. Our objective was to determine the effects of preterm birth, accompanied by antenatal corticosteroid administration, on the structure of the aorta and pulmonary artery, which experience different alterations in pressure flow at birth.. At 11 wk, preterm lambs had significantly thicker aortic walls and a smaller lumen, whereas the morphometry of the pulmonary artery was unaffected. Elastin deposition was markedly increased in the aorta and pulmonary artery and smooth muscle content was reduced in the aorta only. In preterm lambs we found injury in the aorta only; controls were unaffected.. We conclude that moderate preterm birth after antenatal betamethasone can cause injury and persistent alterations in the structure and composition of the aorta, with lesser effects in the pulmonary artery. Our findings suggest that preterm birth may increase the risk of atherosclerosis and aortic aneurysms in later life.. Using an established ovine model of preterm birth, lambs were born at 0.9 of gestation and underwent necropsy at 11 wk after birth; controls were born at term.

Topics: Adrenal Cortex Hormones; Androstenols; Animals; Aorta; Betamethasone; Cardiovascular Diseases; Collagen; Disease Models, Animal; Drug Administration Schedule; Elastin; Female; Gestational Age; Pregnancy; Premature Birth; Pulmonary Artery; Sheep

Aortic valve disease (AVD) occurs in 2.5% of the general population and often requires surgical intervention. Aortic valve malformation (AVM) underlies the majority of cases, suggesting a developmental etiology. Elastin haploinsufficiency results in complex cardiovascular problems, and 20-45% of patients have AVM and/or AVD. Elastin insufficient (Eln+/-) mice demonstrate AVM and latent AVD due to abnormalities in the valve annulus region. The objective of this study was to examine extracellular matrix (ECM) remodeling and biomechanical properties in regional aortic valve tissue and determine the impact of early AVM on late AVD in the Eln+/- mouse model. Aortic valve ECM composition and remodeling from juvenile, adult, and aged stages were evaluated in Eln+/- mice using histology, ELISA, immunohistochemistry and gelatin zymography. Aortic valve tissue biomechanical properties were determined using micropipette aspiration. Cartilage-like nodules were demonstrated within the valve annulus region at all stages identifying a developmental abnormality preceding AVD. Interestingly, maladaptive ECM remodeling was observed in early AVM without AVD and worsened with late AVD, as evidenced by increased MMP-2 and MMP-9 expression and activity, as well as abnormalities in ADAMTS-mediated versican processing. Cleaved versican was increased in the valve annulus region of aged Eln+/- mice, and this abnormality correlated temporally with adverse alterations in valve tissue biomechanical properties and the manifestation of AVD. These findings identify maladaptive ECM remodeling in functional AVM as an early disease process with a progressive natural history, similar to that seen in human AVD, emphasizing the importance of the annulus region in pathogenesis. Combining molecular and engineering approaches provides complementary mechanistic insights that may be informative in the search for new therapeutic targets and durable valve bioprostheses.

Topics: ADAM Proteins; ADAMTS9 Protein; Animals; Aortic Diseases; Aortic Valve; Biomechanical Phenomena; Disease Models, Animal; Elastin; Enzyme Activation; Enzyme-Linked Immunosorbent Assay; Extracellular Matrix; Female; Haploinsufficiency; Heart Valve Diseases; Immunohistochemistry; Male; Matrix Metalloproteinase 9; Mice; Mice, Inbred C57BL; Structure-Activity Relationship; Tensile Strength; Versicans

MicroRNAs (miRs) regulate gene expression at the posttranscriptional level and play crucial roles in vascular integrity. As such, they may have a role in modifying abdominal aortic aneurysm (AAA) expansion, the pathophysiological mechanisms of which remain incompletely explored. Here, we investigate the role of miRs in 2 murine models of experimental AAA: the porcine pancreatic elastase (PPE) infusion model in C57BL/6 mice and the AngII infusion model in Apoe-/- mice. AAA development was accompanied by decreased aortic expression of miR-29b, along with increased expression of known miR-29b targets, Col1a1, Col3a1, Col5a1, and Eln, in both models. In vivo administration of locked nucleic acid anti-miR-29b greatly increased collagen expression, leading to an early fibrotic response in the abdominal aortic wall and resulting in a significant reduction in AAA progression over time in both models. In contrast, overexpression of miR-29b using a lentiviral vector led to augmented AAA expansion and significant increase of aortic rupture rate. Cell culture studies identified aortic fibroblasts as the likely vascular cell type mediating the profibrotic effects of miR-29b modulation. A similar pattern of reduced miR-29b expression and increased target gene expression was observed in human AAA tissue samples compared with that in organ donor controls. These data suggest that therapeutic manipulation of miR-29b and its target genes holds promise for limiting AAA disease progression and protecting from rupture.

Topics: Adolescent; Aged; Aneurysm, Ruptured; Angiotensin II; Animals; Aortic Aneurysm, Abdominal; Apolipoproteins E; Collagen; Disease Models, Animal; Disease Progression; Elastin; Gene Expression; Humans; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; MicroRNAs; Middle Aged; Pancreatic Elastase; Protein Isoforms; Swine; Young Adult

A hallmark feature of Williams-Beuren Syndrome (WBS) is a generalized arteriopathy due to elastin deficiency, presenting as stenoses of medium and large arteries and leading to hypertension and other cardiovascular complications. Deletion of a functional NCF1 gene copy has been shown to protect a proportion of WBS patients against hypertension, likely through reduced NADPH-oxidase (NOX)-mediated oxidative stress. DD mice, carrying a 0.67 Mb heterozygous deletion including the Eln gene, presented with a generalized arteriopathy, hypertension, and cardiac hypertrophy, associated with elevated angiotensin II (angII), oxidative stress parameters, and Ncf1 expression. Genetic (by crossing with Ncf1 mutant) and/or pharmacological (with ang II type 1 receptor blocker, losartan, or NOX inhibitor apocynin) reduction of NOX activity controlled hormonal and biochemical parameters in DD mice, resulting in normalized blood pressure and improved cardiovascular histology. We provide strong evidence for implication of the redox system in the pathophysiology of the cardiovascular disease in a mouse model of WBS. The phenotype of these mice can be ameliorated by either genetic or pharmacological intervention reducing NOX activity, likely through reduced angII-mediated oxidative stress. Therefore, anti-NOX therapy merits evaluation to prevent the potentially serious cardiovascular complications of WBS, as well as in other cardiovascular disorders mediated by similar pathogenic mechanism.

Topics: Acetophenones; Angiotensin II; Angiotensin II Type 1 Receptor Blockers; Animals; Arteries; Blood Pressure; Cardiomegaly; Constriction, Pathologic; Disease Models, Animal; Elastin; Enzyme Activation; Enzyme Inhibitors; Humans; Hypertension; Losartan; Mice; NADPH Oxidases; Oxidative Stress; Sequence Deletion; Williams Syndrome

An ideal pharmaceutical treatment for abdominal aortic aneurysm (AAA) is to prevent aneurysm formation and development (further dilatation of pre-existing aneurysm). Recent studies have reported that oxidative stress with reactive oxygen species (ROS) is crucial in aneurysm formation. We hypothesized that edaravone, a free-radical scavenger, would attenuate vascular oxidative stress and inhibit AAA formation and development.. An AAA model induced with intraluminal elastase and extraluminal calcium chloride was created in 42 rats. Thirty-six rats were divided three groups: a low-dose (group LD; 1 mg/kg/d), high-dose (group HD; 5 mg/kg/d), and control (group C, saline). Edaravone or saline was intraperitoneally injected twice daily, starting 30 minutes before aneurysm preparation. The remaining six rats (group DA) received a delayed edaravone injection (5 mg/kg/d) intraperitoneally, starting 7 days after aneurysm preparation to 28 days. AAA dilatation ratio was calculated. Pathologic examination was performed. ROS expression was semi-quantified by dihydroethidium staining and the oxidative product of DNA induced by ROS, 8-hydroxydeoxyguanosine (8-OHdG), by immunohistochemical staining.. At day 7, ROS expression and 8-OHdG-positive cells in aneurysm walls were decreased by edaravone treatment (ROS expression: 3.0 ± 0.5 in group LD, 1.7 ± 0.3 in group HD, and 4.8 ± 0.7 in group C; 8-OHdG-positive cells: 106.2 ± 7.8 cells in group LD, 64.5 ± 7.7 cells in group HD, and 136.6 ± 7.4 cells in group C; P < .0001), compared with group C. Edaravone treatment significantly reduced messenger RNA expressions of cytokines and matrix metalloproteinases (MMPs) in aneurysm walls (MMP-2: 1.1 ± 0.5 in group LD, 0.6 ± 0.1 in group HD, and 2.3 ± 0.4 in group C; P < .001; MMP-9: 1.2 ± 0.1 in group LD, 0.2 ± 0.6 in group HD, and 2.4 ± 0.2 in group C; P < .001). At day 28, aortic walls in groups LD and HD were less dilated, with increased wall thickness and elastin content than those in group C (dilatation ratio: 204.7% ± 16.0% in group C, 156.5% ± 6.6% in group LD, 136.7% ± 2.0% in group HD; P < .0001). Delayed edaravone administration significantly prevented further aneurysm dilatation, with increased elastin content (155.2% ± 2.9% at day 7, 153.1% ± 11.6% at day 28; not significant).. Edaravone inhibition of ROS can prevent aneurysm formation and expansion in the rat AAA model. Free-radical scavenger edaravone might be an effective pharmaceutical agent for AAA in clinical practice.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Animals; Antipyrine; Aorta, Abdominal; Aortic Aneurysm, Abdominal; Apoptosis; Biomarkers; Calcium Chloride; Deoxyguanosine; Dilatation, Pathologic; Disease Models, Animal; Disease Progression; Drug Administration Schedule; Edaravone; Elastin; Free Radical Scavengers; Gene Expression Regulation; Immunohistochemistry; Injections, Intraperitoneal; Interleukin-1beta; Male; Matrix Metalloproteinase 2; Matrix Metalloproteinase 9; Oxidative Stress; Pancreatic Elastase; Rats; Rats, Sprague-Dawley; Reactive Oxygen Species; Time Factors; Tumor Necrosis Factor-alpha

A variety of polymeric nanoparticles have been developed for bioimaging applications. This study reports on the use of a 50 nm recombinant protein nanoparticle with a multivalent surface as a vehicle for functionalization with a model imaging agent. Multiple fluorescent probes were covalently conjugated to surface amines of crosslinked amphiphilic elastin-mimetic protein micelles using N-hydroxysuccinimide ester chemistry. In vivo fluorescence imaging confirmed that protein micelles selectively accumulated at sites of angioplasty induced vessel wall injury, presumably via an enhanced permeability and retention effect. This investigation demonstrates the potential of amphiphilic protein micelles to be used as a vehicle for selective imaging of sites associated with a disrupted or leaky endothelium.

Topics: Amino Acid Sequence; Angioplasty, Balloon; Animals; Aorta; Disease Models, Animal; Elastin; Evans Blue; Fluorescent Dyes; Imaging, Three-Dimensional; Micelles; Molecular Sequence Data; Particle Size; Rats; Rats, Wistar; Scattering, Radiation; Staining and Labeling; Surface Properties; Surface-Active Agents; Ultraviolet Rays

Elastin-like polypeptides (ELP) aggregate in response to mild hyperthermia, but remain soluble under normal physiologic conditions. ELP macromolecules can accumulate in solid tumors because of the enhanced permeability and retention effect. Tumor retention of ELPs can be further enhanced through hyperthermia-induced aggregation of ELPs by local heating of the tumor. We evaluated the therapeutic potential of ELPs in delivering doxorubicin in the E0771 syngeneic mouse breast cancer model. The ELP-Dox conjugate consisted of a cell-penetrating peptide at the N-terminus and the 6-maleimidocaproyl hydrazone derivative of doxorubicin at the C-terminus of ELP. The acid-sensitive hydrazone linker ensured release of doxorubicin in the lysosomes/endosomes after cellular uptake of the drug conjugate. ELP-Dox dosed at 5 mg doxorubicin equivalent/kg, extended the plasma half-life of doxorubicin to 5.5 hours. In addition, tumor uptake of ELP-Dox increased 2-fold when hyperthermia was applied, and was also enhanced compared to free doxorubicin. Although high levels of doxorubicin were found in the heart of animals treated with free doxorubicin, no detectable levels of doxorubicin were found in ELP-Dox-treated animals, indicating a correlation between tumor targeting and reduction of potential cardiac toxicity by ELP-Dox. At an optimal dose of 12 mg doxorubicin equivalent/kg, ELP-Dox in combination with hyperthermia induced a complete tumor growth inhibition, which was distinctly superior to free drug that only moderately inhibited tumor growth. In summary, our findings show that thermal targeting of ELP increases the potency of doxorubicin underlying the potential of exploiting ELPs to enhance the therapeutic efficacy of conventional anticancer drugs.

Topics: Animals; Biological Transport; Cell Line, Tumor; Cell-Penetrating Peptides; Combined Modality Therapy; Disease Models, Animal; Doxorubicin; Elastin; Female; Humans; Hyperthermia, Induced; Maximum Tolerated Dose; Mice; Mice, Inbred C57BL; Neoplasms

The aim of this study was to demonstrate the feasibility of high-resolution 3-dimensional aortic vessel wall imaging using a novel elastin-specific magnetic resonance contrast agent (ESMA) in a large animal model.. The thoracic aortic vessel wall of 6 Landrace pigs was imaged using a novel ESMA and a nonspecific control agent. On day 1, imaging was performed before and after the administration of a nonspecific control agent, gadolinium diethylenetriamine pentaacetic acid (Gd-DTPA; Bayer Schering AG, Berlin, Germany). On day 3, identical scans were repeated before and after the administration of a novel ESMA (Lantheus Medical Imaging, North Billerica, Massachusetts). Three-dimensional inversion recovery gradient echo delayed-enhancement imaging and magnetic resonance (MR) angiography of the thoracic aortic vessel wall were performed on a 1.5-T MR scanner (Achieva; Philips Medical Systems, the Netherlands). The signal-to-noise ratio and the contrast-to-noise ratio of arterial wall enhancement, including the time course of enhancement, were assessed for ESMA and Gd-DTPA. After the completion of imaging sessions, histology, electron microscopy, and inductively coupled plasma mass spectroscopy were performed to localize and quantify the gadolinium bound to the arterial vessel wall.. Administration of ESMA resulted in a strong enhancement of the aortic vessel wall on delayed-enhancement imaging, whereas no significant enhancement could be measured with Gd-DTPA. Ninety to 100 minutes after the administration of ESMA, significantly higher signal-to-noise ratio and contrast-to-noise ratio could be measured compared with the administration of Gd-DTPA (45.7 ± 9.6 vs 13.2 ± 3.5, P < 0.05 and 41.9 ± 9.1 vs 5.2 ± 2.0, P < 0.05). A significant correlation (0.96; P < 0.01) between area measurements derived from ESMA scans and aortic MR angiography scans could be found. Electron microscopy and inductively coupled plasma mass spectroscopy confirmed the colocalization of ESMA with elastic fibers.. We demonstrate the feasibility of aortic vessel wall imaging using a novel ESMA in a large animal model under conditions resembling a clinical setting. Such an approach could be useful for the fast 3-dimensional assessment of the arterial vessel wall in the context of atherosclerosis, aortic aneurysms, and hypertension.

Topics: Animals; Aorta, Thoracic; Aortic Diseases; Contrast Media; Disease Models, Animal; Elastin; Feasibility Studies; Female; Imaging, Three-Dimensional; Molecular Imaging; Swine

Age-associated arterial remodeling involves arterial wall collagen deposition and elastin fragmentation, as well as an increase in arterial pressure. This arterial remodeling is linked to proinflammatory signaling, including transforming growth factor-β1, monocyte chemoattractant protein 1, and proendothelin 1, activated by extracellular matrix metalloproteinases (MMPs) and orchestrated, in part, by the transcriptional factor ets-1. We tested the hypothesis that inhibition of MMP activation can decelerate the age-associated arterial proinflammation and its attendant increase in arterial pressure. Indeed, chronic administration of a broad-spectrum MMP inhibitor, PD166739, via a daily gavage, to 16-month-old rats for 8 months markedly blunted the expected age-associated increases in arterial pressure. This was accompanied by the following: (1) inhibition of the age-associated increases in aortic gelatinase and interstitial collagenase activity in situ; (2) preservation of the elastic fiber network integrity; (3) a reduction of collagen deposition; (4) a reduction of monocyte chemoattractant protein 1 and transforming growth factor-β1 activation; (5) a diminution in the activity of the profibrogenic signaling molecule SMAD-2/3 phosphorylation; (6) inhibition of proendothelin 1 activation; and (7) downregulation of expression of ets-1. Acute exposure of cultured vascular smooth muscle cells in vitro to proendothelin 1 increased both the transcription and translation of ets-1, and these effects were markedly reduced by MMP inhibition. Furthermore, infection of vascular smooth muscle cells with an adenovirus harboring a full-length ets-1 cDNA increased activities of both transforming growth factor-β1 and monocyte chemoattractant protein 1. Collectively, our results indicate that MMP inhibition retards age-associated arterial proinflammatory signaling, and this is accompanied by preservation of intact elastin fibers, a reduction in collagen, and blunting of an age-associated increase in blood pressure.

Topics: Aging; Animals; Arteritis; Blood Pressure; Chemokine CCL2; Collagen; Disease Models, Animal; Elastin; Endothelin-1; Enzyme Inhibitors; Gelatinases; Hydroxamic Acids; Hypertension; Male; Matrix Metalloproteinase Inhibitors; Matrix Metalloproteinases; Oligopeptides; Protein Precursors; Proto-Oncogene Protein c-ets-1; Rats; Rats, Inbred BN; Rats, Inbred F344; Transforming Growth Factor beta1

An in vitro biomechanical and imaging study generated from an in vivo porcine model of early stage degenerative disc disease was used to evaluate mechanical property restoration, comparing 2 minimally invasive injection techniques.. To evaluate the ability of an injectable hydrogel to restore the mechanical properties of spinal motion segments with early stage disc degeneration, comparing 2 minimally invasive injection techniques.. Treatment of early-stage disc degeneration may benefit from a combination of tissue engineering and minimally invasive therapeutic approaches. A recently developed hydrogel, thiol-modified hyaluronan elastin-like polypeptide (TMHA/EP) composite, has demonstrated potential as an injectable nucleus replacement.. From a total of thirteen 35-kg Yorkshire boars, early-stage lumbar disc degeneration was introduced into 10 pigs via injection of chondroitinase ABC. After degeneration, 8 pigs received TMHA/EP augmentation; 1 disc via direct needle injection and a second using a modified kyphoplasty approach. High-resolution magnetic resonance images were acquired of the excised spinal motion segments, followed by biomechanical testing in axial compression, flexion-extension, lateral bending, and torsion.. The degenerate control motion segments were generally less stiff and more flexible than healthy controls. The injection of TMHA/EP into the degenerated nucleus produced similar mechanical stiffness to healthy controls. The direct-injected discs showed a dispersive pattern of TMHA/EP within the nucleus, whereas the modified kyphoplasty method yielded a bolus of hydrogel. Yet, mechanical behavior was comparable considering the 2 minimally invasive augmentation techniques.. The TMHA/EP composite can restore initial mechanical behavior in early-stage disc degeneration. Although both augmentation methods yielded mechanical properties comparable with healthy controls, direct injection represents a simpler technique, uses a smaller-gauge needle, does not introduce air into the disc, and yields a dispersive pattern that may be beneficial for future delivery of cells or growth factors.

Topics: Animals; Biomechanical Phenomena; Disease Models, Animal; Elastin; Humans; Hyaluronic Acid; Hydrogel, Polyethylene Glycol Dimethacrylate; Intervertebral Disc; Intervertebral Disc Degeneration; Lumbar Vertebrae; Minimally Invasive Surgical Procedures; Peptides; Range of Motion, Articular; Sulfhydryl Compounds; Swine; Time Factors; Tissue Engineering; Total Disc Replacement; Treatment Outcome; Viscosupplements

Mast cells participate importantly in abdominal aortic aneurysms (AAAs) by releasing inflammatory cytokines to promote vascular cell protease expression and arterial wall remodelling. Mast cells accumulate in AAA lesions during disease progression, but the exact chemokines by which mast cells migrate to the site of vascular inflammation remain unknown. This study tested the hypothesis that mast cells use chemokine (C-C motif) receptor 2 (CCR2) for their accumulation in experimental mouse AAA lesions.. We generated mast cell and apolipoprotein E double-deficient (Apoe(-/-)Kit(W-sh/W-sh)) mice and found that they were protected from angiotensin II (Ang II) chronic infusion-induced AAAs compared with Apoe(-/-) littermates. Using bone-marrow derived mast cells (BMMC) from Apoe(-/-) mice and CCR2 double-deficient (Apoe(-/-)Ccr2(-/-)) mice, we demonstrated that Apoe(-/-)Kit(W-sh/W-sh) mice receiving BMMC from Apoe(-/-)Ccr2(-/-) mice, but not those from Apoe(-/-) mice, remained protected from AAA formation. Adoptive transfer of BMMC from Apoe(-/-) mice into Apoe(-/-)Kit(W-sh/W-sh) mice also increased lesion content of macrophages, T cells, and MHC class II-positive cells; there was also increased apoptosis, angiogenesis, cell proliferation, elastin fragmentation, and medial smooth muscle cell loss. In contrast, adoptive transfer of BMMC from Apoe(-/-)Ccr2(-/-) mice into Apoe(-/-)Kit(W-sh/W-sh) mice did not affect these variables.. The increased AAA formation and associated lesion characteristics in Apoe(-/-)Kit(W-sh/W-sh) mice after receiving BMMC from Apoe(-/-) mice, but not from Apoe(-/-)Ccr2(-/-) mice, suggests that mast cells use CCR2 as the chemokine receptor for their recruitment in Ang II-induced mouse AAA lesions.

Topics: Adoptive Transfer; Angiotensin II; Animals; Aorta, Abdominal; Aortic Aneurysm, Abdominal; Apolipoproteins E; Apoptosis; Cell Proliferation; Cells, Cultured; Chemotaxis; Disease Models, Animal; Elastin; Male; Mast Cells; Mice; Mice, Inbred C57BL; Mice, Knockout; Muscle, Smooth, Vascular; Myocytes, Smooth Muscle; Neovascularization, Pathologic; Proto-Oncogene Proteins c-kit; Receptors, CCR2

Abdominal aortic aneurysm (AAA) is characterized by extensive aortic wall matrix degradation that contributes to the remodelling and eventual rupture of the arterial wall. Elastinolytic cathepsin S (Cat S) is highly expressed in human aneurysmal lesions, but whether it contributes to the pathogenesis of AAA remains unknown.. AAAs were induced in apolipoprotein E (ApoE) and Cat S compound mutant (Apoe(-/-)Ctss(-/-)) mice and in ApoE-deficient Cat S wild-type littermates (Apoe(-/-)Ctss(+/+)) by chronic angiotensin II infusion, and AAA lesions were analysed after 28 days. We found that Cat S expression increased significantly in mouse AAA lesions. The AAA incidence in Apoe(-/-)Ctss(-/-) mice was much lower than that in Apoe(-/-)Ctss(+/+) mice (10 vs. 80%). Cat S deficiency significantly reduced external and luminal abdominal aortic diameters, medial elastin fragmentation, and adventitia collagen content. Cat S deficiency reduced aortic lesion expression and the activity of matrix metalloproteinase (MMP)-2, MMP-9, and Cat K, but not the activity of other major cathepsins, such as Cat B and Cat L. Absence of Cat S significantly reduced AAA lesion media smooth muscle cell (SMC) apoptosis, lesion adventitia microvessel content, and inflammatory cell accumulation and proliferation. In vitro studies proved that Cat S helps promote SMC apoptosis, angiogenesis, monocyte and T-cell transmigration, and T-cell proliferation--all of which are essential to AAA pathogenesis.. These data provide direct evidence that Cat S plays an important role in AAA formation and suggest that Cat S is a new therapeutic target for human AAA.

Topics: Angiotensin II; Animals; Aorta, Abdominal; Aortic Aneurysm, Abdominal; Apolipoproteins E; Apoptosis; Cathepsin K; Cathepsins; CD3 Complex; Cells, Cultured; Collagen; Disease Models, Animal; Elastin; Inflammation; Male; Matrix Metalloproteinase 2; Matrix Metalloproteinase 9; Mice; Mice, Inbred C57BL; Mice, Knockout; Muscle, Smooth, Vascular; Myocytes, Smooth Muscle; Neovascularization, Pathologic; T-Lymphocytes; Time Factors

Coronary artery damage from Kawasaki disease (KD) is closely linked to the dysfunction of endothelial progenitor cells (EPCs). The aim of the present study was to evaluate the therapeutic effect of EPCs transplantation in KD model.. Lactobacillus casei cell wall extract (LCWE)-induced KD model in C57BL/6 mice was established. The model mice were injected intravenously with bone marrow-derived in vitro expanded EPCs. Histological evaluation, number of circulating EPCs and the function of bone marrow EPCs were examined at day 56.. Inflammation was found around the coronary artery of the model mice after 14 days, Elastin breakdown was observed after 56 days. CM-Dil labeled EPCs incorporated into vessel repairing foci was found. At day 56, the number of peripheral EPCs in the KD model group was lower than in EPCs transplanted and control group. The functional index of bone marrow EPCs from the KD model group decreased in proliferation, adhesion and migration. Increased number of circulating EPCs and improved function were observed on the EPCs transplanted group compared with model group.. Exogenously administered EPCs, which represent a novel strategy could prevent the dysfunction of EPCs, accelerate the repair of coronary artery endothelium lesion and decrease the occurrence of aneurysm.

Topics: Animals; Cell Adhesion; Cell Proliferation; Disease Models, Animal; Elastin; Endothelial Cells; Male; Mice; Mucocutaneous Lymph Node Syndrome; Stem Cell Transplantation; Stem Cells

Inhibiting the growth of small abdominal aortic aneurysms (AAAs) is a clinically valuable goal and fills an important therapeutic void. Based on studies in animals and humans, inhibition of the activity of elastolytic matrix metalloproteinases (MMPs) has the potential to slow AAA expansion and limit morbidity and the need for surgery. Previous attempts to make use of the synthetic MMP inhibitors in the treatment of chronic conditions have been limited by intolerable side effects. The limited-spectrum synthetic MMP inhibitor, XL784, was well tolerated and devoid of side-effects associated with other nonspecific MMP inhibitors in phase I studies. We hypothesized that clinically relevant doses of XL784 would be effective at inhibiting aneurysm development in a mouse model.. The 14-day elastase-perfusion model of AAA in mice was used. An initial screening study of XL784 (50 [n = 17], 125 [n = 17], and 250 mg/kg [n = 18]) administered via gavage daily until harvest. Controls received diluent alone (n = 18) or doxycycline in drinking water (n = 19). Aortic diameter was measured pre-perfusion (AD(pre)) and at harvest (AD(har)). A second study used XL784 (250 [n = 9]; 375 [n = 9], and 500 mg/kg [n = 14]) and diluent alone (n = 9) administered via gavage. The percentage dilatation [%ΔAD = [(AD(har) - AD(pre))/AD(pre)] ×100] was calculated and elastin and inflammatory content was scored.. All mice tolerated the treatments similarly. Control mice all developed aneurysms with a mean %ΔAD of 158.5% ± 4.3%. Treatment with all doses of XL784 and doxycycline were effective in inhibiting aortic dilatation. There was a clear dose-response relationship between XL784 and reductions in aortic dilatation at harvest (50 mg/kg 140.4% ± 3.2%; 125 mg/kg 129.3% ± 5.1%; 250 mg/kg 119.2% ± 3.5%; all Ps < .01 compared to control). This continued with the higher doses (375 mg/kg 88.6% ± 4.4%; 500 mg/kg 76.0% ± 3.5%). The highest 2 doses of XL784 tested were more effective than doxycycline (112.2% ± 2.0%, P < .05) in inhibiting maximal dilatation of the aorta after elastase perfusion.

Topics: Administration, Oral; Animals; Anti-Inflammatory Agents, Non-Steroidal; Aorta, Abdominal; Aortic Aneurysm, Abdominal; Aortic Rupture; Dilatation, Pathologic; Disease Models, Animal; Disease Progression; Dose-Response Relationship, Drug; Elastin; Half-Life; Male; Matrix Metalloproteinase 2; Matrix Metalloproteinase Inhibitors; Mice; Mice, Inbred C57BL; Pancreatic Elastase; Random Allocation; Severity of Illness Index

Vascular calcification is common in chronic kidney disease, where cardiovascular mortality remains the leading cause of death. Patients with kidney disease are often prescribed vitamin D receptor agonists (VDRAs) that confer a survival benefit, but the underlying mechanisms remain unclear. Here we tested two VDRAs in a mouse chronic kidney disease model where dietary phosphate loading induced aortic medial calcification. Mice were given intraperitoneal calcitriol or paricalcitol three times per week for 3 weeks. These treatments were associated with half of the aortic calcification compared to no therapy, and there was no difference between the two agents. In the setting of a high-phosphate diet, serum parathyroid hormone and calcium levels were not significantly altered by treatment. VDRA therapy was associated with increased serum and urine klotho levels, increased phosphaturia, correction of hyperphosphatemia, and lowering of serum fibroblast growth factor-23. There was no effect on elastin remodeling or inflammation; however, the expression of the anticalcification factor, osteopontin, in aortic medial cells was increased. Paricalcitol upregulated osteopontin secretion from mouse vascular smooth muscle cells in culture. Thus, klotho and osteopontin were upregulated by VDRA therapy in chronic kidney disease, independent of changes in serum parathyroid hormone and calcium.

Topics: Animals; Aorta; Aortic Diseases; Calcitriol; Calcium; Cells, Cultured; Diet; Disease Models, Animal; Elastin; Ergocalciferols; Female; Fibroblast Growth Factor-23; Fibroblast Growth Factors; Glucuronidase; Injections, Intraperitoneal; Klotho Proteins; Mice; Mice, Inbred C57BL; Mice, Inbred DBA; Muscle, Smooth, Vascular; Myocytes, Smooth Muscle; Osteopontin; Parathyroid Hormone; Phosphates; Receptors, Calcitriol; Renal Insufficiency, Chronic; Time Factors; Up-Regulation; Vascular Calcification

Pseudoxanthoma elasticum (PXE) is a heritable disorder characterized by mineralization of connective tissue, which leads to pathology in eye, skin and blood vessels. The disease is caused by mutations in ABCC6. To learn more about PXE eye pathology, we analyzed Bruch's membrane (BM) of the eye of an Abcc6 knockout mouse. With age, BM differences between Abcc6-/- and wild type mice became apparent. At two years of age, von Kossa staining indicated clear calcification of BM in Abcc6-/- mice, and not in healthy controls. Electron microscopy revealed BM changes as early as at 10 months of age: Fibrous structures with abnormal high electron-density were present in the central layers of BM of Abcc6-/- mice. EDX (Energy Dispersive X-ray) analysis demonstrated that these structures contained elevated levels of Ca, P and O. Since some of these electron-dense structures showed a banding pattern with periodicity of about 50 nm, they most likely represent calcified collagen fibers. Immunoelectron microscopy showed that the calcified structures were positive for collagen III. Remarkably, the elastic layer of BM appeared to have a normal ultrastructure, even in 2.5 year old Abcc6-/- mice. Our results suggest that Abcc6 deficiency in the mouse causes calcification of BM. While PXE is considered to affect primarily the elastic fibers, we found predominantly mineralization of collagen fibers.

Topics: Animals; ATP-Binding Cassette Transporters; Bruch Membrane; Calcinosis; Collagen Type III; Disease Models, Animal; Elastin; Female; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Microscopy, Immunoelectron; Multidrug Resistance-Associated Proteins; Pseudoxanthoma Elasticum; Spectrometry, X-Ray Emission

Tumour necrosis factor (TNF) is a major pro-inflammatory cytokine involved in multiple inflammatory diseases. The detrimental activity of TNF can be blocked by various antagonists, and commercial therapeutics based upon this principle have been approved for treatment of diseases including rheumatoid arthritis, Crohn's disease and psoriasis. In a search for new, improved anti-inflammatory therapeutics we have designed a single-domain monoclonal antibody (V(H) H), which recognizes TNF. The antibody component (TNF-V(H) H) is based upon an anti-human TNF Camelidae heavy-chain monoclonal antibody, which was linked to an elastin-like polypeptide (ELP). We demonstrate that ELP fusion to the TNF-V(H) H enhances accumulation of the fusion protein during biomanufacturing in transgenic tobacco plants. With this study, we show for the first time that this plant-derived anti-human TNF-V(H) H antibody was biologically active in vivo. Therefore, therapeutic application of TNF-V(H) H-ELP fusion protein was tested in humanized TNF mice and was shown to be effective in preventing death caused by septic shock. The in vivo persistence of the ELPylated antibody was ∼24 fold longer than that of non-ELPylated TNF-V(H) H.

Topics: Animals; Antibodies, Monoclonal; Disease Models, Animal; Elastin; Escherichia coli; Galactose; Gene Expression; Humans; L Cells; Lipopolysaccharides; Mice; Nicotiana; Peptides; Plants, Genetically Modified; Recombinant Fusion Proteins; Shock, Septic; Tumor Necrosis Factor-alpha

This study sought to determine the effect of combined treatment of hypoxia plus indomethacin on pulmonary vascular remodeling in fetal rats.. Hypoxia and indomethacin were used to treat pregnant rats during 19-21 days of gestation. The adventitia, media, and intima of pulmonary arteries from fetal rats were assessed. Western blots were used for determining the abundance of smooth muscle specific alpha-actin protein (α-SMA), elastin, and endothelial nitric oxide synthase (eNOS) in lung tissues. Plasma brain-type natriuretic peptide (BNP) levels, reflecting the increased right ventricular load or pulmonary arterial pressure, were detected.. The ratio of left ventricular free wall plus septum to right ventricular weight significantly increased in hypoxia plus indomethacin-treated group. The medial thickness percentage of pulmonary arteries of < 100 μm and ≥100 μm in diameter from hypoxia plus indomethacin-treated group was higher than that from control or single treatment group. Vascular elastin area percentage and immunostaining density of eNOS from the combined-treated group were higher than other groups. The relative abundance of α-SMA, elastin, and eNOS and plasma BNP levels in hypoxia plus indomethacin-treated group also significantly increased compared with other groups.. Hypoxia and indomethacin had synergistic effect on fetal pulmonary vascular remodeling. This rat model induced by combined treatments can mimic human persistent pulmonary hypertension of the newborn.

Topics: Actins; Animals; Animals, Newborn; Blotting, Western; Cardiovascular Agents; Disease Models, Animal; Elastin; Female; Humans; Hypoxia; Indomethacin; Infant, Newborn; Lung; Myocardium; Natriuretic Peptide, Brain; Nitric Oxide Synthase Type III; Persistent Fetal Circulation Syndrome; Pulmonary Artery; Rats; Rats, Sprague-Dawley

Treatment of congenital tracheal stenosis/atresia remains essentially unresolved. Previous models of this disease entity have been restricted to rodents and the chick. We sought to establish the principles of a large, surgical animal model of this spectrum of fetal anomalies.. Fetal lambs (n = 8) underwent open surgery at 90-112 days gestation. Their cervical tracheas were encircled by a biocompatible polytetrafluoroethylene wrap, so as to extrinsically restrict their external diameter by 25%. Survivors (n = 7) were killed at different time points post-operatively before term. The manipulated tracheal segments were compared with their respective proximal portions (controls). Analyses included morphometry, histology and quantitative extracellular matrix measurements.. At necropsy, the typical gross appearance of tracheal stenosis/atresia was present in all manipulated tracheal segments. Histological findings included the virtual disappearance of the membranous portion of the trachea, along with infolding, fragmentation, and/or posterior fusion of cartilaginous rings, often with disappearance of the airway mucosa. There were significant decreases in diameter (P < 0.001) and total collagen levels (P = 0.005) on the manipulated trachea compared with the control portions. No significant differences were observed in overall elastin or glycosaminoglycan contents. A significant time-dependent increase in elastin was noted on the control, but not the experimental side.. In a surgical ovine model, controlled extrinsic compression of the fetal trachea leads to morphological and biochemical findings compatible with the congenital tracheal stenosis/atresia spectrum. This simple and easily reproducible prenatal model can be instrumental in the development of emerging therapies for these congenital anomalies.

Topics: Animals; Biocompatible Materials; Collagen; Disease Models, Animal; Elastin; Extracellular Matrix; Female; Fetus; Fluorocarbon Polymers; Organogenesis; Pregnancy; Sheep; Trachea; Tracheal Stenosis

The Williams-Beuren syndrome (WBS) is a genetic disorder caused by a heterozygous ~1.5-Mb deletion. The aim of this study was to determine how the genetic changes in a Wbs mouse model alter Eln expression, blood pressure, vessel structure, and abdominal aortic wall dynamics in vivo.. Elastin (ELN) transcript levels were quantified by qRT-PCR and blood pressure was measured with a tail cuff system. M-mode ultrasound was used to track pulsatile abdominal aortic wall motion. Aortas were sectioned and stained to determine medial lamellar structure.. ELN transcript levels were reduced by 38-41% in Wbs mice lacking one copy of the ELN gene. These mice also had a 10-20% increase in mean blood pressure and significantly reduced circumferential cyclic strain (p < 0.001). Finally, histological sections showed disorganized and fragmented elastin sheets in Wbs mice, but not the characteristic increase in lamellar units seen in Eln(+/-) mice.. The deletion of Eln in this Wbs mouse model results in lower gene expression, hypertension, reduced cyclic strain, and fragmented elastin sheets. The observation that the number of medial lamellar units is normal in Wbs deletion mice, which is in contrast to Eln(+/-) mice, suggests other genes may be involved in vascular development.

Topics: Animals; Aorta, Abdominal; Blood Pressure; Cardiovascular Abnormalities; Chromosome Deletion; Disease Models, Animal; Elasticity; Elastin; Female; Gene Expression; Male; Mice; Mice, Inbred C57BL; Phenotype; Ultrasonography; Williams Syndrome

Remodeling by its very nature implies synthesis and degradation of extracellular matrix components (such as elastin, collagen, and connexins). Most of the vascular matrix metalloproteinase (MMP) are latent because of the presence of constitutive nitric oxide (NO). However, during oxidative stress peroxinitrite (ONOO-) activates the latent MMPs and instigates vascular remodeling. Interestingly, in mesenteric artery, homocysteine (Hcy) decreases the NO bio-availability, and folic acid (FA, an Hcy-lowering agent) mitigates the Hcy-mediated mesentery artery dysfunction. Dimethylarginine dimethylaminohydrolase-2 (DDAH-2) and endothelial nitric oxide synthase (eNOS) increases NO production. The hypothesis was that the Hcy decreased NO bio-availability, in part, activating MMP, decreasing elastin, DDAH-2, eNOS and increased vasomotor response by increasing connexin. To test this hypothesis,the authors used 12-week-old C57BJ/L6 wild type (WT) and hyperhomocysteinemic (HHcy)-cystathione beta synthase heterozygote knockout (CBS+/-) mice. Blood pressure measurements were made by radio-telemetry. WT and MMP-9 knockout mice were administered with Hcy (0.67 mg/ml in drinking water). Superior mesenteric artery and mesenteric arcade were analyzed with light and confocal microscopy. The protein expressions were measured by western blot analysis. The mRNA levels for MMP-9 were measured by RT-PCR. The data showed decreased DDAH-2 and eNOS expressions in mesentery in CBS-/+ mice compared with WT mice. Immuno-fluorescence and western blot results suggest increased MMP-9 and connexin-40 expression in mesenteric arcades of CBS-/+ mice compared with WT mice. The wall thickness of third-order mesenteric artery was increased in CBS-/+ mice compared to WT mice. Hcy treatment increased blood pressure in WT mice. Interestingly, in MMP-9 KO, Hcy did not increase blood pressure. These results may suggest that HHcy causes mesenteric artery remodeling and narrowing by activating MMP-9 and decreasing DDAH-2 and eNOS expressions, compromising the blood flow, instigating hypertension, and acute abdomen pain.

Topics: Abdominal Pain; Amidohydrolases; Animals; Blood Pressure; Blood Pressure Monitoring, Ambulatory; Blotting, Western; Connexins; Cystathionine beta-Synthase; Disease Models, Animal; Elasticity; Elastin; Extracellular Matrix Proteins; Fluorescent Antibody Technique; Gap Junction alpha-5 Protein; Homocysteine; Hyperhomocysteinemia; Hypertension; Male; Matrix Metalloproteinase 9; Mesenteric Artery, Superior; Mice; Mice, Inbred C57BL; Mice, Knockout; Microscopy, Confocal; Microscopy, Video; Nitric Oxide Synthase Type III; Nitrites; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Splanchnic Circulation; Telemetry; Vascular Resistance

Cathepsin-L (CTSL) is a member of the lysozomal cysteine protease family, which participates in remodelling of various tissues. Herein, we sought to examine the potential regulation of CTSL in cardiac remodelling post-infarction.. Experimental myocardial infarction (MI) was created in CTSL-deficient (Ctsl(-/-)) mice (B6 × FSB/GnEi a/a Ctsl(fs)/J) and wild-type littermates (Ctsl(+/+)) by left coronary artery ligation. At days 3, 7, 14, and 28 post-MI, we monitored survival rate and evaluated cardiac function, morphology, and molecular endpoints of repair and remodelling. Survival was 56% in Ctsl(-/-) mice in contrast to 80% (P < 0.05) in Ctsl(+/+) mice post-MI by day 28. The Ctsl(-/-) mice exhibited greater scar dilatation, wall thinning, and worse cardiac dysfunction when compared with Ctsl(+/+) mice. Cardiac matrix metallopeptidase-9 (MMP-9) activity was also diminished, and c-kit-positive cells, natural killer cells, fibrocytes, and monocytes mobilized to peripheral blood and deposited to the infarcted myocardium were significantly decreased in Ctsl(-/-) mice. Furthermore, the local inflammatory response, and granulocyte-colony stimulating factor, stem cell factor (SCF), and stromal cell-derived factor-1 (SDF-1α) expression, as well as cell proliferation, revascularization, and myofibroblast deposition were significantly decreased in Ctsl(-/-) mice compared with Ctsl(+/+) mice.. Our data indicate that CTSL regulates cardiac repair and remodelling post-MI through a mechanism with multiple pathways.

Topics: Animals; Bone Marrow; Cathepsin L; Cell Proliferation; Collagen; Cytokines; Disease Models, Animal; Elastin; Endothelial Cells; Enzyme Activation; Male; Matrix Metalloproteinase 9; Mice; Mice, Knockout; Myocardial Infarction; Myocardium; Myofibroblasts; Neovascularization, Physiologic; Proto-Oncogene Proteins c-kit; Time Factors; Ventricular Function, Left; Ventricular Remodeling

Biomechanical, in vitro, and initial in vivo evaluation of a thiol-modified hyaluronan (TM-HA) and elastin-like polypeptide (ELP) composite hydrogel for nucleus pulposus (NP) tissue engineering.. To investigate the utility of a TM-HA and ELP composite material as a potential tissue-engineering scaffold to reconstitute the NP in early degenerative disc disease (DDD) on the basis of both biomechanical and biologic parameters.. DDD is a common ailment with enormous medical, psychosocial, and economic ramifications. Only end-stage surgical therapies are currently widely available. A less invasive, early stage therapy may provide a clinically relevant treatment option.. TM-HA and ELP were combined in various concentrations and cross-linked using poly (ethylene glycol) diacrylate. Resulting materials were evaluated biomechanically using confined compression to determine biphasic material properties. In vitro cell culture with human intervertebral disc (IVD) cells seeded within TM-HA/ELP scaffolds was analyzed for cell viability and phenotype. The hydrogels' materials were evaluated in an established New Zealand White (NZW) rabbit model of DDD.. The addition of ELP to TM-HA-based hydrogels resulted in a stiffer construct, which is less stiff than native NP but has time-dependant loading characteristics that may be desirable when injected into the IVD. In vitro experiments demonstrated 70% cell viability at 3 weeks with apparent maintenance of phenotype on the basis of morphologic and immunohistochemical data. The addition of ELP had a positive desirable biomechanical effect but did not have a significant positive or negative biologic effect on cell activity. The in vivo feasibility study demonstrated favorable material characteristics and biocompatibility for application as a minimally invasive injectable NP supplement.. TM-HA-based hydrogels provide a hospitable environment for human IVD cells and have material characteristics, particularly when supplemented with ELPs that are attractive for potential application as an injectable NP supplement.

Topics: Animals; Biocompatible Materials; Biomechanical Phenomena; Cell Survival; Cells, Cultured; Cross-Linking Reagents; Disease Models, Animal; Elasticity; Elastin; Feasibility Studies; Humans; Hyaluronic Acid; Hydrogels; Intervertebral Disc; Intervertebral Disc Degeneration; Magnetic Resonance Imaging; Materials Testing; Peptides; Phenotype; Polyethylene Glycols; Rabbits; Sulfhydryl Compounds; Time Factors; Tissue Engineering; Tissue Scaffolds

Currently, percutaneous aortic valve (PAV) replacement devices are being investigated to treat aortic stenosis in patients deemed to be of too high a risk for conventional open-chest surgery. Successful PAV deployment and function are heavily reliant on the tissue-stent interaction. Many PAV feasibility trials have been conducted with porcine models under the assumption that these tissues are similar to human; however, this assumption may not be valid. The goal of this study was to characterize and compare the biomechanical properties of aged human and porcine aortic tissues.. The biaxial mechanical properties of the left coronary sinus, right coronary sinus, non-coronary sinus, and ascending aorta of eight aged human (90.1 ± 6.8 years) and 10 porcine (6-9 months) hearts were quantified. Tissue structure was analyzed via histological techniques.. Aged human aortic tissues were significantly stiffer than the corresponding porcine tissues in both the circumferential and longitudinal directions (p < 0.001). In addition, the nearly linear stress-strain behavior of the porcine tissues, compared with the highly nonlinear response of the human tissues at a low strain range, suggested structural differences between the aortic tissues from these two species. Histological analysis revealed that porcine samples were composed of more elastin and less collagen fibers than the respective human samples.. Significant material and structural differences were observed between the human and porcine tissues, which raise questions on the validity of using porcine models to investigate the biomechanics involved in PAV intervention.

Topics: Aged; Aged, 80 and over; Aging; Animals; Aorta; Aortic Valve Stenosis; Collagen; Disease Models, Animal; Elasticity; Elastin; Female; Heart Valve Prosthesis Implantation; Humans; Male; Models, Cardiovascular; Sinus of Valsalva; Species Specificity; Stress, Mechanical; Sus scrofa

We hypothesized that fetal innate immune responses to lipopolysaccharide-induced chorioamnionitis would alter postnatal systemic immune and airway responsiveness.. Ewes received intraamniotic injections with saline or lipopolysaccharide at 90, 100, and 110 days of gestation. Immune status and airway responsiveness were evaluated at term and at 7 weeks of age.. At term, lymphocytes, monocytes, and neutrophils were significantly increased (respectively, 24-fold, 127-fold, and 31,000-fold) in lungs and blood monocytes became Toll-like receptor 2 responsive after lipopolysaccharide exposures. Furthermore, CD4 and CD4/CD25 lymphocytes were increased in thymus and lymph nodes. At 7 weeks, airway reactivity decreased and concentrations of CD8 cytotoxic T lymphocytes changed in the lungs and thymus relative to controls.. Early gestational lipopolysaccharide exposure increased leukocyte responsiveness at term. Decreased airway reactivity and changes in lymphocytes at 7 weeks postnatal demonstrate persistent effects of fetal exposure to LPS.

Topics: Animals; Bronchoalveolar Lavage Fluid; Chorioamnionitis; Disease Models, Animal; Elastin; Escherichia coli Infections; Female; Immunity, Innate; Interleukin-2 Receptor alpha Subunit; Leukocytes; Lipopolysaccharides; Lung; Pregnancy; Sheep; Thymus Gland; Toll-Like Receptor 2; Transforming Growth Factor beta1

Arterial medial calcification (AMC), a hallmark of vascular disease in uremic patients, is highly correlated with serum phosphate levels and cardiovascular mortality. To determine the mechanisms of AMC, mice were made uremic by partial right-side renal ablation (week 0), followed by left-side nephrectomy at week 2. At 3 weeks, mice were switched to a high-phosphate diet, and various parameters of disease progression were examined over time. Serum phosphate, calcium, and fibroblast growth factor 23 (FGF-23) were up-regulated as early as week 4. Whereas serum phosphate and calcium levels declined to normal by 10 weeks, FGF-23 levels remained elevated through 16 weeks, consistent with an increased phosphate load. Elastin turnover and vascular smooth muscle cell (VSMC) phenotype change were early events, detected by week 4 and before AMC. Both AMC and VSMC loss were significantly elevated by week 8. Matrix metalloprotease 2 (MMP-2) and cathepsin S were present at baseline and were significantly elevated at weeks 8 and 12. In contrast, MMP-9 was not up-regulated until week 12. These findings over time suggest that VSMC phenotype change and VSMC loss (early phosphate-dependent events) may be necessary and sufficient to promote AMC in uremic mice fed a high-phosphate diet, whereas elastin degradation might be necessary but is not sufficient to induce AMC (because elastin degradation occurred also in uremic mice on a normal-phosphate diet, but they did not develop AMC).

Topics: Animals; Calcinosis; Cell Death; Diet; Disease Models, Animal; Disease Progression; Elastin; Enzyme Activation; Fibroblast Growth Factor-23; Immunohistochemistry; Kidney Failure, Chronic; Matrix Metalloproteinases; Mice; Muscle, Smooth, Vascular; Myocytes, Smooth Muscle; Phenotype; Phosphates; Time Factors; Tunica Media; Uremia

Although abdominal aortic aneurysms (AAA) can be potentially stabilized by inhibiting inflammatory cell recruitment and their release of proteolytic enzymes, active AAA regression is not possible without regeneration of new elastic matrix structures. Unfortunately, postneonatal vascular smooth muscle cells (SMCs), healthy, and likely more so, diseased cells, poorly synthesize or remodel elastic fibers, impeding any effort directed at regenerative AAA treatment. Previously, we determined the eleastogenic benefits of oligomers (HA-o; 4-6 mers) of the glycosaminoglycan, hyaluronan (HA) and transforming growth factor-β1 (TGF-β1) to healthy SMCs. Since AAAs are often diagnosed only late in development when matrix disruption is severe, we now determine if elastogenic upregulation of SMCs from late-stage AAAs (>100% diameter increase) is possible. AAAs were induced by perfusion of rat infrarenal aortae with porcine pancreatic elastase. Elastic matrix degradation, vessel expansion (∼120%), inflammatory cell infiltration, and enhanced activity of matrix-metalloproteases (MMPs) 2 and 9 resulted, paralleling human AAAs. Aneurysmal SMCs (EaRASMCs) maintained a diseased phenotype in 2D cell culture and exhibited patterns of gene expression different from healthy rat aortic SMCs (RASMCs). Relative to passage-matched healthy RASMCs, unstimulated EaRASMCs produced far less tropoelastin and matrix elastin. Exogenous TGF-β and HA-o (termed "factors") significantly decreased EaRASMC proliferation and enhanced tropoelastin synthesis, though only at the highest provided dose combination (20 mg/mL of HA-o, 10 ng/mL of TGF-β); despite such enhancement, tropoelastin amounts were only ∼40% of amounts synthesized by healthy RASMC cultures. Differently, elastic matrix synthesis was enhanced beyond amounts synthesized by healthy RASMCs (112%), even at lower doses of factors (2 mg/mL of HA-o and 5 ng/mL of TGF-β). The factors also enhanced elastic fiber deposition over untreated EaRASMC cultures and restored several genes whose expression was altered in EaRASMC cultures back to levels expressed by healthy RASMCs. However, the activity of MMPs 2 and 9 generated by EaRASMC cultures was unaffected by the factors/factor dose. The study confirms that SMCs from advanced AAAs can be elastogenically induced, although much higher doses of elastogenic factors are required for induction relative to healthy SMCs. Also, the factors do not appear to inhibit MMP activity, vital to preserve existing

Topics: Animals; Aorta; Aortic Aneurysm, Abdominal; Cell Proliferation; Disease Models, Animal; Disease Progression; Elastin; Extracellular Matrix; Fluorescent Antibody Technique; Gene Expression Profiling; Gene Expression Regulation; Humans; Male; Myocytes, Smooth Muscle; Oligonucleotide Array Sequence Analysis; Pancreatic Elastase; Perfusion; Phenotype; Protein Processing, Post-Translational; Rats; Rats, Sprague-Dawley; Staining and Labeling; Sus scrofa; Transforming Growth Factor beta

Kawasaki disease (KD) is an acute inflammatory illness marked by coronary arteritis. However, the factors increasing susceptibility to coronary artery lesions are unknown. Because transforming growth factor (TGF) β increases elastin synthesis and suppresses proteolysis, we hypothesized that, in contrast to the benefit observed in aneurysms forming in those with Marfan syndrome, inhibition of TGF-β would worsen inflammatory-induced coronary artery lesions. By using a murine model of KD in which injection of Lactobacillus casei wall extract (LCWE) induces coronary arteritis, we show that LCWE increased TGF-β signaling in the coronary smooth muscle cells beginning at 2 days and continuing through 14 days, the point of peak coronary inflammation. By 42 days, LCWE caused fragmentation of the internal and external elastic lamina. Blocking TGF-β by administration of a neutralizing antibody accentuated the LCWE-mediated fragmentation of elastin and induced an overall loss of medial elastin without increasing the inflammatory response. We attributed these increased pathological characteristics to a reduction in the proteolytic inhibitor, plasminogen activator inhibitor-1, and an associated threefold increase in matrix metalloproteinase 9 activity compared with LCWE alone. Therefore, our data demonstrate that in the coronary arteritis associated with KD, TGF-β suppresses elastin degradation by inhibiting plasmin-mediated matrix metalloproteinase 9 activation. Thus, strategies to block TGF-β, used in those with Marfan syndrome, are unlikely to be beneficial and could be detrimental.

Topics: Animals; Cell Wall; Collagen Type I; Complex Mixtures; Coronary Artery Disease; Coronary Vessels; Disease Models, Animal; Elastin; Lacticaseibacillus casei; Matrix Metalloproteinase 9; Mice; Mucocutaneous Lymph Node Syndrome; Plasminogen Activator Inhibitor 1; Protein Processing, Post-Translational; Signal Transduction; Transforming Growth Factor beta; Tropoelastin

The extracellular matrix (ECM) plays an important role in the pathogenesis of atherosclerosis and in-stent restenosis. Elastin is an essential component of the ECM. ECM degradation can lead to plaque destabilization, whereas enhanced synthesis typically leads to vessel wall remodeling resulting in arterial stenosis or in-stent restenosis after stent implantation. The objective of this study was to demonstrate the feasibility of MRI of vascular remodeling using a novel elastin-binding contrast agent (BMS-753951).. Coronary injury was induced in 6 pigs by endothelial denudation and stent placement. At day 28, delayed-enhancement MRI coronary vessel wall imaging was performed before and after injection of gadolinium-diethylene triamine pentaacetic acid (Gd-DTPA). Two days later, DE-MRI was repeated after administration of BMS-753951. Contrast-to-noise-ratio and areas of enhancement were determined. Delayed-enhancement MRI with BMS-753951 caused strong enhancement of the aortic, pulmonary artery, and injured coronary artery walls, whereas Gd-DTPA did not. Delayed-enhancement MRI of the stented coronary artery with BMS-753951 yielded a 3-fold higher contrast-to-noise-ratio when compared with the balloon-injured and control coronary artery (21±6 versus 7±3 versus 6±4; P<0.001). The area of enhancement correlated well with the area of remodeling obtained from histological data (R(2)=0.86, P<0.05).. We demonstrate the noninvasive detection and quantification of vascular remodeling in an animal model of coronary vessel wall injury using an elastin-specific MR contrast agent. This novel approach may be useful for the assessment of coronary vessel wall remodeling in patients with suspected coronary artery disease. Further studies in atherosclerotic animal models and degenerative ECM disease are now warranted.

Topics: Angioplasty, Balloon, Coronary; Animals; Contrast Media; Coronary Angiography; Coronary Restenosis; Coronary Vessels; Disease Models, Animal; Elastin; Feasibility Studies; Female; Gadolinium DTPA; Heart Injuries; Magnetic Resonance Imaging; Predictive Value of Tests; Stents; Swine; Time Factors; Vascular System Injuries

Pelvic organ prolapse (POP) is a disabling disorder in women characterized by a loss of pelvic floor support leading to the herniation of the uterus into or through the vagina. POP is a complex problem that likely involves multiple mechanisms, and available therapies are limited. In this issue of the JCI, Budatha et al. explore the dual role carried out by fibulin-5 in facilitating the assembly of normal elastic fibers and inhibiting MMP-9 activity, revealing a new mechanism critical to the maintenance of pelvic organ support.

Topics: Animals; Disease Models, Animal; Elastic Tissue; Elastin; Extracellular Matrix Proteins; Female; Humans; Matrix Metalloproteinase 9; Mice; Mice, Transgenic; Pelvic Floor; Pelvic Organ Prolapse; Protein Structure, Tertiary; Tropoelastin; Vagina

The causality of the associations between cellular and mechanical mechanisms of abdominal aortic aneurysm (AAA) formation has not been completely defined. Because reactive oxygen species are established mediators of AAA growth and remodeling, our objective was to investigate oxidative stress-induced alterations in aortic biomechanics and microstructure during subclinical AAA development. We investigated the mechanisms of AAA in an angiotensin II (ANG II) infusion model of AAA in apolipoprotein E-deficient (apoE(-/-)) mice that overexpress catalase in vascular smooth muscle cells (apoE(-/-)xTg(SMC-Cat)). At baseline, aortas from apoE(-/-)xTg(SMC-Cat) exhibited increased stiffness and the microstructure was characterized by 50% more collagen content and less elastin fragmentation. ANG II treatment for 7 days in apoE(-/-) mice altered the transmural distribution of suprarenal aortic circumferential strain (quantified by opening angle, which increased from 130 ± 1° at baseline to 198 ± 8° after 7 days of ANG II treatment) without obvious changes in the aortic microstructure. No differences in aortic mechanical behavior or suprarenal opening angle were observed in apoE(-/-)xTg(SMC-Cat) after 7 days of ANG II treatment. These data suggest that at the earliest stages of AAA development H(2)O(2) is functionally important and is involved in the control of local variations in remodeling across the vessel wall. They further suggest that reduced elastin integrity at baseline may predispose the abdominal aorta to aneurysmal mechanical remodeling.

Topics: Analysis of Variance; Angiotensin II; Animals; Aorta, Abdominal; Aortic Aneurysm, Abdominal; Apolipoproteins E; Biomechanical Phenomena; Blood Pressure; Catalase; Collagen; Disease Models, Animal; Elastin; Hydrogen Peroxide; Mice; Mice, Knockout; Mice, Transgenic; Stress, Mechanical; Time Factors; Up-Regulation

Liver growth factor (LGF) is an endogenous albumin-bilirubin complex with antihypertensive effects in spontaneously hypertensive rats (SHR). We assessed the actions of LGF treatment on SHR mesenteric resistance and intramyocardial arteries (MRA and IMA, respectively), heart, and vascular smooth muscle cells (VSMC). SHR and Wistar-Kyoto (WKY) rats treated with vehicle or LGF (4.5 μg LGF/rat, 4 ip injections over 12 days) were used. Intra-arterial blood pressure was measured in anesthetized rats. The heart was weighted and paraffin-embedded. Proliferation, ploidy, and fibronectin deposition were studied in carotid artery-derived VSMC by immunocytochemistry. In MRA, we assessed: 1) geometry and mechanics by pressure myography; 2) function by wire myography; 3) collagen by sirius red staining and polarized light microscopy, and 4) elastin, cell density, nitric oxide (NO), and superoxide anion by confocal microscopy. Heart sections were used to assess cell density and collagen content in IMA. Left ventricular hypertrophy (LVH) regression was assessed by echocardiography. LGF reduced blood pressure only in SHR. LGF in vitro or as treatment normalized the alterations in proliferation and fibronectin in SHR-derived VSMC with no effect on WKY cells. In MRA, LGF treatment normalized collagen, elastin, and VSMC content and passive mechanical properties. In addition, it improved NO availability through reduction of superoxide anion. In IMA, LGF treatment normalized perivascular collagen and VSMC density, improving the wall-to-lumen ratio. Paired experiments demonstrated a partial regression of SHR LVH by LGF treatment. The effective cardiovascular antifibrotic and regenerative actions of LGF support its potential in the treatment of hypertension and its complications.

Topics: Analysis of Variance; Animals; Antihypertensive Agents; Bilirubin; Blood Pressure; Cell Proliferation; Cells, Cultured; Collagen; Coronary Vessels; Disease Models, Animal; Dose-Response Relationship, Drug; Elastin; Extracellular Matrix; Fibronectins; Fibrosis; Hypertension; Hypertrophy, Left Ventricular; Immunohistochemistry; Male; Mesenteric Arteries; Microscopy, Confocal; Microscopy, Polarization; Muscle, Smooth, Vascular; Myocardium; Myocytes, Smooth Muscle; Myography; Nitric Oxide; Nitric Oxide Synthase; Rats; Rats, Inbred SHR; Rats, Inbred WKY; Serum Albumin; Serum Albumin, Human; Superoxides; Ultrasonography; Vascular Resistance; Vasodilation; Vasodilator Agents; Ventricular Remodeling

Surface-associated and secreted proteins represent primarily exposed components of Aspergillus fumigatus during host infection. Several secreted proteins are known to be involved in defense mechanisms or immune evasion, thus, probably contributing to pathogenicity. Furthermore, several secreted antigens were identified as possible biomarkers for the verification of diseases caused by Aspergillus species. Nevertheless, there is only limited knowledge about the composition of the secretome and about molecular functions of particular proteins. To identify secreted proteins potentially essential for virulence, the core secretome of A. fumigatus grown in minimal medium was determined. Two-dimensional gel electrophoretic separation and subsequent MALDI-TOF-MS/MS analyses resulted in the identification of 64 different proteins. Additionally, secretome analyses of A. fumigatus utilizing elastin, collagen or keratin as main carbon and nitrogen source were performed. Thereby, the alkaline serine protease Alp1 was identified as the most abundant protein and hence presumably represents an important protease during host infection. Interestingly, the Asp-hemolysin (Asp-HS), which belongs to the protein family of aegerolysins and which was often suggested to be involved in fungal virulence, was present in the secretome under all growth conditions tested. In addition, a second, non-secreted protein with an aegerolysin domain annotated as Asp-hemolysin-like (HS-like) protein can be found to be encoded in the genome of A. fumigatus. Generation and analysis of Asp-HS and HS-like deletion strains revealed no differences in phenotype compared to the corresponding wild-type strain. Furthermore, hemolysis and cytotoxicity was not altered in both single-deletion and double-deletion mutants lacking both aegerolysin genes. All mutant strains showed no attenuation in virulence in a mouse infection model for invasive pulmonary aspergillosis. Overall, this study provides a comprehensive analysis of secreted proteins of A. fumigatus and a detailed characterization of hemolysin mutants.

Topics: Animals; Aspergillus fumigatus; Carbon; Collagen; Culture Media; Disease Models, Animal; Elastin; Electrophoresis, Gel, Two-Dimensional; Female; Fungal Proteins; Gene Deletion; Hemolysin Proteins; Invasive Pulmonary Aspergillosis; Keratins; Mice; Nitrogen; Proteome; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Virulence; Virulence Factors

Elastin is the primary component of elastic fibres in arteries, which contribute significantly to the structural integrity of the wall. Fibrillin-1 is a microfibrillar glycoprotein that appears to stabilize elastic fibres mechanically and thereby to delay a fatigue-induced loss of function due to long-term repetitive loading. Whereas prior studies have addressed some aspects of ageing-related changes in the overall mechanical properties of arteries in mouse models of Marfan syndrome, we sought to assess for the first time the load-carrying capability of the elastic fibres early in maturity, prior to the development of ageing-related effects, dilatation, or dissection.. We used elastase to degrade elastin in common carotid arteries excised, at 7-9 weeks of age, from a mouse model (mgR/mgR) of Marfan syndrome that expresses fibrillin-1 at 15-25% of normal levels. In vitro biaxial mechanical tests performed before and after exposure to elastase suggested that the elastic fibres exhibited a nearly normal load-bearing capability. Observations from nonlinear optical microscopy suggested further that competent elastic fibres not only contribute to load-bearing, they also increase the undulation of collagen fibres, which endows the normal arterial wall with a more compliant response to pressurization.. These findings support the hypothesis that it is an accelerated fatigue-induced damage to or protease-related degradation of initially competent elastic fibres that render arteries in Marfan syndrome increasingly susceptible to dilatation, dissection, and rupture.

Topics: Age Factors; Animals; Biomechanical Phenomena; Carotid Artery, Common; Disease Models, Animal; Disease Progression; Elastic Tissue; Elastin; Fibrillin-1; Fibrillins; Male; Marfan Syndrome; Mice; Mice, Knockout; Microfilament Proteins; Pancreatic Elastase

Quantifying the time course of load-induced changes in arterial wall geometry, microstructure, and properties is fundamental to developing mathematical models of growth and remodeling. Arteries adapt to altered pressure and flow by modifying wall thickness, inner diameter, and axial length via marked cell and matrix turnover. To estimate particular biomaterial implications of such adaptations, we used a 4-fiber family constitutive relation to quantify passive biaxial mechanical behaviors of mouse carotid arteries 0 (control), 7-10, 10-14, or 35-56 days after an aortic arch banding surgery that increased pulse pressure and pulsatile flow in the right carotid artery. In vivo circumferential and axial stretches at mean arterial pressure were, for example, 11% and 26% lower, respectively, in hypertensive carotids 35-56 days after banding than in normotensive controls; this finding is consistent with observations that hypertension decreases distensibility. Interestingly, the strain energy W stored in the carotids at individual in vivo conditions was also less in hypertensive compared with normotensive carotids. For example, at 35-56 days after banding, W was 24%, 39%, and 47% of normal values at diastolic, mean, and systolic pressures, respectively. The energy stored during the cardiac cycle, W(sys)-W(dias), also tended to be less, but this reduction did not reach significance. When computed at normal in vivo values of biaxial stretch, however, W was well above normal for the hypertensive carotids. This net increase resulted from an overall increase in the collagen-related anisotropic contribution to W despite a decrease in the elastin-related isotropic contribution. The latter was consistent with observed decreases in the mass fraction of elastin.

Topics: Animals; Biomechanical Phenomena; Carotid Artery Diseases; Carotid Artery, Common; Collagen; Disease Models, Animal; Elastin; Hypertension; Male; Mice; Mice, Inbred C57BL; Pulsatile Flow; Stress, Mechanical

The sequelae of aortic root dilation are the lethal consequences of Marfan syndrome. The root dilation is attributable to an imbalance between deposition of matrix elements and metalloproteinases in the aortic medial layer as a result of excessive transforming growth factor-beta signaling. This study examined the efficacy and mechanism of statins in attenuating aortic root dilation in Marfan syndrome and compared effects to the other main proposed preventative agent, losartan.. Marfan mice heterozygous for a mutant allele encoding a cysteine substitution in fibrillin-1 (C1039G) were treated daily from 6 weeks old with pravastatin 0.5 g/L or losartan 0.6 g/L. The end points of aortic root diameter (n=25), aortic thickness, and architecture (n=10), elastin volume (n=5), dp/dtmax (maximal rate of change of pressure) (cardiac catheter; n=20), and ultrastructural analysis with stereology (electron microscopy; n=5) were examined. The aortic root diameters of untreated Marfan mice were significantly increased in comparison to normal mice (0.161 ± 0.001 cm vs 0.252 ± 0.004 cm; P<0.01). Pravastatin (0.22 ± 0.003 cm; P<0.01) and losartan (0.221 ± 0.004 cm; P<0.01) produced a significant reduction in aortic root dilation. Both drugs also preserved elastin volume within the medial layer (pravastatin 0.23 ± 0.02 and losartan 0.29 ± 0.03 vs untreated Marfan 0.19 ± 0.02; P=0.01; normal mice 0.27 ± 0.02). Ultrastructural analysis showed a reduction of rough endoplasmic reticulum in smooth muscle cells with pravastatin (0.022 ± 0.004) and losartan (0.013 ± 0.001) compared to untreated Marfan mice (0.035 ± 0.004; P<0.01).. Statins are similar to losartan in attenuating aortic root dilation in a mouse model of Marfan syndrome. They appear to act through reducing the excessive protein manufacture by vascular smooth muscle cells, which occurs in the Marfan aorta. As a drug that is relatively well-tolerated for long-term use, it may be useful clinically.

Topics: Angiotensin II Type 1 Receptor Blockers; Animals; Aorta; Aortic Diseases; Dilatation, Pathologic; Disease Models, Animal; Elastin; Endoplasmic Reticulum; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Losartan; Male; Marfan Syndrome; Mice; Mice, Mutant Strains; Muscle, Smooth, Vascular; Pravastatin; Treatment Outcome; Tunica Media

We have performed multi-photon image reconstructions as well as polarization state analyses inside an artery wall affected by atherosclerosis to investigate the changes in collagen structure. Mice, either healthy or affected by spontaneous atherosclerosis, have been used for this purpose. A two-photon imaging system has been used to investigate atherosclerotic lesions in the ascending aorta of mice. Second harmonic imaging has been performed alternatively on healthy samples and on affected region. The reconstructed images show that the spatial distribution of the collagen network seems disorganized by the disease. The polarization state studies reveal however that the apparent disorganization of the collagen is related to its spatially diffuse distribution and that the internal structure of the collagen fibers is not affected by the disease. In addition, a theoretical simulation of the second harmonic polarization states shows that they are consistent with the known 3D structure of the collagen network.

Topics: Animals; Aorta; Arteries; Atherosclerosis; Collagen; Disease Models, Animal; Elastin; Humans; Image Processing, Computer-Assisted; Mice; Mice, Inbred C57BL; Mice, Knockout; Microscopy, Confocal; Microscopy, Polarization; Models, Statistical; Normal Distribution

Abdominal aortic aneurysms (AAAs) expand as a consequence of extracellular matrix destruction, and vascular smooth muscle cell (VSMC) depletion. Transforming growth factor (TGF)-beta 1 overexpression stabilizes expanding AAAs in rat. Cyclosporine A (CsA) promotes tissue accumulation and induces TGF -beta1 and, could thereby exert beneficial effects on AAA remodelling and expansion. In this study, we assessed whether a short administration of CsA could durably stabilize AAAs through TGF-beta induction. We showed that CsA induced TGF-beta1 and decreased MMP-9 expression dose-dependently in fragments of human AAAs in vitro, and in animal models of AAA in vivo. CsA prevented AAA formation at 14 days in the rat elastase (diameter increase: CsA: 131.9±44.2%; vehicle: 225.9±57.0%, P = 0.003) and calcium chloride mouse models (diameters: CsA: 0.72±0.14 mm; vehicle: 1.10±0.11 mm, P = .008), preserved elastic fiber network and VSMC content, and decreased inflammation. A seven day administration of CsA stabilized formed AAAs in rats seven weeks after drug withdrawal (diameter increase: CsA: 14.2±15.1%; vehicle: 45.2±13.7%, P = .017), down-regulated wall inflammation, and increased αSMA-positive cell content. Co-administration of a blocking anti-TGF-beta antibody abrogated CsA impact on inflammation, αSMA-positive cell accumulation and diameter control in expanding AAAs. Our study demonstrates that pharmacological induction of TGF-beta1 by a short course of CsA administration represents a new approach to induce aneurysm stabilization by shifting the degradation/repair balance towards healing.

Topics: Animals; Aortic Aneurysm, Abdominal; Calcium Chloride; Cyclosporine; Disease Models, Animal; Elastin; Humans; Inflammation; Male; Matrix Metalloproteinase 9; Mice; Mice, Inbred C57BL; Muscle, Smooth, Vascular; Myocytes, Smooth Muscle; Pancreatic Elastase; Rats; Rats, Wistar; Tissue Inhibitor of Metalloproteinase-1; Transforming Growth Factor beta

Treatment of cerebral aneurysms by endovascular deployment of liquid embolic agents has been proposed as an alternative strategy to conventional coiling, and new materials are being developed for embolization. In this study, the authors used a single-injection, biocompatible, biodegradable and pH-responsive acrylated chitosan (aCHN) with conjugated vascular endothelial growth factor (rhVEGF) in a rat aneurysm model.. The efficacy of the aCHN formulation with rhVEGF was tested using a common carotid artery occlusion model in rats, and the extent of embolization was evaluated using quantitative, qualitative, and histopathological techniques after 14 days of implantation.. The mean occlusion was significantly greater for the rhVEGF/aCHN-treated group (96.8 +/- 3.0%) than for the group receiving aCHN (74.7 +/- 5.6%) (p < 0.01). Through qualitative evaluation, intimal and medial proliferation were significantly greater with rhVEGF/aCHN than with aCHN and controls (p < 0.001). Degradation of the aCHN filler was monitored in concert with the production of extracellular matrix components. Macrophages migrated in and proliferated inside the occluded carotid artery lumens were identified by histological and immunostainings. Results showed resorption of chitosan with concurrent development of collagen and elastin into the vessel lumen, suggesting clot maturation into fibrosis.. Chitosan with a bioactive agent such as rhVEGF showed excellent results in occluding aneurysms in a rat model.

Topics: Animals; Biocompatible Materials; Brain; Carotid Artery Diseases; Carotid Artery, Common; Chitosan; Collagen; Disease Models, Animal; Elastin; Embolization, Therapeutic; Extracellular Matrix; Fibrosis; Hydrogen-Ion Concentration; Intracranial Aneurysm; Macrophages; Mitogens; Rats; Rats, Sprague-Dawley; Vascular Endothelial Growth Factor A

Preterm infants are at high risk of developing ventilator-induced lung injury. We have used an animal model of in utero ventilation (IUV) to investigate the separate effects of ventilation and acute oxygen exposure on the very immature lung. Fetal sheep were ventilated in utero at 110 d gestation for 6 h with 100, 21, or 0% (100% nitrogen) oxygen (n = 5 each) and survived in utero, without further ventilation, until tissue collection at 118 d. Nonventilated 110 d and 118 d fetuses were used as controls. All IUV exposed fetuses had reduced secondary septal crest densities and increased elastin staining irrespective of the inspired oxygen concentration. IUV with 100% and 21% oxygen, but not 100% nitrogen, increased lung tissue volumes and myofibroblast differentiation and apoptosis within the distal lung parenchyma in a dose-dependent manner. This study shows that IUV without oxygen can reduce alveolarization, whereas ventilation with oxygen (6 h), even at levels found in air (21%), increases distal lung tissue volumes, elastin deposition, myofibroblast differentiation, and apoptosis.

Topics: Animals; Apoptosis; Carbon Dioxide; Caspase 3; Cell Differentiation; Collagen; Disease Models, Animal; Dose-Response Relationship, Drug; Elastin; Female; Fetal Blood; Fibroblasts; Gestational Age; Lung; Oxygen; Oxygen Inhalation Therapy; Positive-Pressure Respiration; Pregnancy; Sheep; Time Factors; Ventilator-Induced Lung Injury

To determine the role of multinucleated giant cells (MGCs) in cardiovascular diseases.. MGCs are a hallmark of giant cell arteritis. They are also described in atherosclerotic plaques from aortic aneurysms and carotid and coronary arteries. Herein, we demonstrate that the cholate-containing Paigen diet yields many MGCs in atherosclerotic plaques of apolipoprotein E-/- mice. These mice revealed a 4-fold increase in MGC numbers when compared with mice on a Western or Paigen diet without cholate. Most of the MGCs stained intensively for cathepsin K and were located at fibrous caps and close to damaged elastic laminae, with associated medial smooth muscle cell depletion. During in vitro experiments, MGCs demonstrated a 6-fold increase in elastolytic activity when compared with macrophages and facilitated transmigration of smooth muscle cells through a collagen-elastin matrix. An elastin-derived hexapeptide (Val-Gly-Val-Ala-Pro-Gly [VGVAPG]) significantly increased the rate of macrophage fusion, providing a possible mechanism of in vivo MGC formation. Comparable to the mouse model, human specimens from carotid arteries and aortic aneurysms contained cathepsin K-positive MGCs.. Apolipoprotein E-/- mice fed a Paigen diet provide a model to analyze the tissue-destructive role of MGCs in vascular diseases.

Topics: Animals; Antigens, Differentiation; Aortic Aneurysm; Apolipoproteins E; Atherosclerosis; Carotid Artery Diseases; Cathepsin K; Cell Fusion; Cell Movement; Cells, Cultured; Cholates; Collagen; Dietary Fats; Disease Models, Animal; Elastin; Endotoxins; Giant Cells, Foreign-Body; Humans; Immunohistochemistry; Interleukin-4; Macrophages, Peritoneal; Mice; Mice, Knockout; Muscle, Smooth, Vascular; Myocytes, Smooth Muscle; Oligopeptides; Time Factors; Toll-Like Receptor 4

Discoidin domain receptor (DDR)1 is a collagen receptor expressed on both smooth muscle cells (SMCs) and macrophages, where it plays important roles regulating cell and matrix accumulation during atherogenesis. Systemic deletion of DDR1 resulted in attenuated plaque growth but accelerated matrix accumulation in LDLR-deficient mice. Deletion of DDR1 solely on bone marrow-derived cells resulted in decreased macrophage accumulation and plaque growth but no change in matrix accumulation.. These findings led us to hypothesize that accelerated matrix accumulation was attributable to the increased synthetic ability of Ddr1(-/-) resident vascular wall SMCs.. We used bone marrow transplantation to generate chimeric mice and investigate the role of SMC DDR1 during atherogenesis. Mice with deficiency of DDR1 in vessel wall-derived cells (Ddr1(+/+-->-/-)) or control mice (Ddr1(+/+-->+/+)) were fed an atherogenic diet for 12 weeks. We observed a 3.8-fold increase in the size of aortic sinus plaques in Ddr1(+/+-->-/-) compared to Ddr1(+/+-->+/+) mice. This was attributed to pronounced accumulation of collagen, elastin, proteoglycans, and fibronectin and resulted in a thickened fibrous cap. The enhanced matrix accumulation decreased the proportion of plaque area occupied by cells but was associated with a shift in the cellular composition of the lesions toward increased numbers of vessel wall-derived SMCs compared to bone marrow-derived macrophages. In vitro studies confirmed that Ddr1(-/-) SMCs expressed more matrix, proliferated more, and migrated farther than Ddr1(+/+) SMCs.. DDR1 expression on resident vessel wall SMCs limits proliferation, migration and matrix accumulation during atherogenesis.

Topics: Animals; Aortic Diseases; Atherosclerosis; Bone Marrow Transplantation; Cell Movement; Cell Proliferation; Collagen; Discoidin Domain Receptor 1; Disease Models, Animal; Elastin; Extracellular Matrix Proteins; Female; Fibronectins; Fibrosis; Macrophages; Male; Matrix Metalloproteinases; Mice; Mice, Knockout; Mitogen-Activated Protein Kinases; Muscle, Smooth, Vascular; Myocytes, Smooth Muscle; Proteoglycans; Receptor Protein-Tyrosine Kinases; RNA, Messenger; Time Factors; Transplantation Chimera; Up-Regulation

The effect of cold low-pressure plasma treatment on neovascularization of a dermis substitute was evaluated in a mouse model.. Collagen-elastin matrices (Matriderm(®)) were used as scaffolds. Low-pressure argon/hydrogene plasma-treated scaffolds were transplanted into the dorsal skinfold chambers of balb/c mice (group 1, n=10). Untreated scaffolds served as controls (group 2, n=10). Intravital fluorescence microscopy was performed within the border zone of the scaffolds on days 1, 5 and 10. Functional vessel density (FVD), vessel diameter, intervascular distance, microvascular permeability, and leukocyte-endothelium interaction were analyzed.. An increase of FVD associated with a reduction of the intervascular distance was observed. Statistical analysis revealed that the functional vessel density in the border zone of the scaffolds was significantly enhanced in the plasma-treated group compared to controls. For group 1, an increase of FVD from 282±8 cm/cm(2) on days 5 to 315±8 cm/cm(2) on day 10 was observed. Whereas values of 254±7 cm/cm(2) on day 5 and 275±13 cm/cm(2) on day 10 have resulted in group 2 (mean±S.E.M., Student's t-test, p<0.05).. The surface treatment by cold low-pressure plasma intensifies the angiogenesis and accelerates the neovascularization of collagen-elastin matrix.

Topics: Animals; Biocompatible Materials; Burns; Collagen; Disease Models, Animal; Elastin; Mice; Neovascularization, Physiologic; Pressure; Skin; Skin, Artificial; Tissue Engineering; Tissue Scaffolds

Mouse experimental models are commonly utilized tools in biomedical research but remain underrepresented in vocal fold biology, presumably due to the small size of the larynx and limited description of the anatomical, cellular and extracellular composition of the vocal folds. In this study, we provide a whole-mount serial section-based histological description of vocal fold morphology of wild-type FVB strain mice, alongside a histological and immunohistochemical (IHC)-based quantitative analysis of extracellular matrix (ECM) alteration 1, 7, 14, 28, 42 and 56 days following unilateral vocal fold injury. IHC was specific for procollagen type I, collagen type I, collagen type III, collagen type IV, elastin, decorin, fibronectin and hyaluronic acid binding protein 2. The histological description confirmed the presence of a laryngeal alar structural complex in the mouse, which appears to be a morphological feature unique to rodents. The lamina propria appeared uniform without evidence of a distinct layer structure as has been reported in larger animals and humans. Time-dependent alterations in vocal fold morphology, ECM organization and ECM protein/glycoconjugate abundance were observed in injured vocal folds compared to control. The presence of a mature scar was observed between 28 and 42 days postinjury. Morphological and ECM changes following vocal fold injury in the mouse were generally consistent with those reported in other animal models, particularly the rat, although wound repair in the mouse appears to occur at a faster rate.

Topics: Animals; Cicatrix; Collagen Type I; Collagen Type III; Collagen Type IV; Decorin; Disease Models, Animal; Elastin; Extracellular Matrix; Extracellular Matrix Proteins; Fibronectins; Immunohistochemistry; Mice; Rats; Rats, Sprague-Dawley; Serine Endopeptidases; Vocal Cords; Wound Healing

Elastin is a ubiquitous extracellular matrix protein that is highly organized in heart valves and arteries. Because elastic fiber abnormalities are a central feature of degenerative valve disease, we hypothesized that elastin-insufficient mice would manifest viable heart valve disease.. To analyze valve structure and function in elastin-insufficient mice (Eln(+/-)) at neonatal, juvenile, adult, and aged adult stages.. At birth, histochemical analysis demonstrated normal extracellular matrix organization in contrast to the aorta. However, at juvenile and adult stages, thin elongated valves with extracellular matrix disorganization, including elastin fragment infiltration of the annulus, were observed. The valve phenotype worsened by the aged adult stage with overgrowth and proteoglycan replacement of the valve annulus. The progressive nature of elastin insufficiency was also shown by aortic mechanical testing that demonstrated incrementally abnormal tensile stiffness from juvenile to adult stages. Eln(+/-) mice demonstrated increased valve interstitial cell proliferation at the neonatal stage and varied valve interstitial cell activation at early and late stages. Gene expression profile analysis identified decreased transforming growth factor-beta-mediated fibrogenesis signaling in Eln(+/-) valve tissue. Juvenile Eln(+/-) mice demonstrated normal valve function, but progressive valve disease (predominantly aortic regurgitation) was identified in 17% of adult and 70% of aged adult Eln(+/-) mice by echocardiography.. These results identify the Eln(+/-) mouse as a model of latent aortic valve disease and establish a role for elastin dysregulation in valve pathogenesis.

Topics: Animals; Aortic Valve; Disease Models, Animal; Disease Progression; Elastin; Haploidy; Heart Valve Diseases; Mice; Mice, Inbred C57BL; Mice, Mutant Strains

We imaged the protease activity of matrix metalloproteinases (MMPs) upregulated during aneurysm formation, using protease-activatable near-infrared fluorescence probes. We tested whether these protease-activatable sensors can directly report the in vivo activity of the key biomarkers in aneurysm, using our genetically modified fibulin-4 mouse models for aneurysm formation. Mice homozygous for the fibulin-4 reduced-expression allele (fibulin-4(R/R)) show dilatation of the ascending aorta and a tortuous, stiffened aorta resulting from disorganized elastic fiber networks. Strikingly, even a moderate reduction in expression of fibulin-4 in the heterozygous fibulin-4(+/R) mice occasionally results in modest aneurysm formation.. Aorta transcriptome and protein expression analysis of fibulin-4(+/R) and fibulin-4(R/R) animals identified excessive transforming growth factor-β signaling as the critical event in the pathogenesis of aneurysm formation. To determine whether a perturbed elastin lamellar structure arose from induction of transforming growth factor-β-regulated MMPs, we performed gelatin zymography and used a protease-activatable near-infrared fluorescence probe to monitor and quantify MMP upregulation in animals, using various in vivo optical imaging modules and coregistration of the fluorescence signal with CT images of the same animals. Gelatin zymography demonstrated a significant increase in the presence of the active form of MMP-9 in the aortic arch of fibulin-4(R/R) mice. In vivo analysis of MMP upregulation using the near-infrared fluorescence probe and subsequent isosurface concentration mapping from reconstructed tomographic images from fibulin-4(+/R) and fibulin-4(R/R) mice revealed a graded increase in activation of MMPs within the aneurysmal lesions.. We aimed to develop molecular imaging procedures for faster, earlier, and easier recognition of aortic aneurysms. We show that in vivo coregistration of MMP activity by noninvasive tomographic imaging methods allows the detection of increased MMP activity, even before the aneurysm has actually formed.

Topics: Animals; Aorta, Thoracic; Aortic Aneurysm, Thoracic; Aortography; Biomarkers; Biosensing Techniques; Disease Models, Animal; Disease Progression; Early Diagnosis; Elastin; Enzyme Activation; Extracellular Matrix Proteins; Fluorescence; Magnetic Resonance Angiography; Matrix Metalloproteinase 9; Matrix Metalloproteinases; Mice; Mice, Inbred C57BL; Mice, Knockout; Molecular Imaging; Predictive Value of Tests; Signal Transduction; Spectroscopy, Near-Infrared; Tomography, X-Ray Computed; Transforming Growth Factor beta; Up-Regulation

Heterozygous elastin gene mutations cause autosomal dominant cutis laxa associated with emphysema and aortic aneurysms. To investigate the molecular mechanisms leading to cutis laxa in vivo, we generated transgenic mice by pronuclear injection of minigenes encoding normal human tropoelastin (WT) or tropoelastin with a cutis laxa mutation (CL). Three independent founder lines of CL mice showed emphysematous pulmonary airspace enlargement. No consistent dermatological or cardiovascular pathologies were observed. One CL and one WT line were selected for detailed studies. Both mutant and control transgenic animals showed elastin deposition into pulmonary elastic fibers, indicated by increased desmosine levels in the lung and by colocalization of transgenic and endogenous elastin by immunostaining. CL mice showed increased static lung compliance and decreased stiffness of lung tissue. In addition, markers of transforming growth factor-β (TGFβ) signaling and the unfolded protein response (UPR) were elevated together with increased apoptosis in the lungs of CL animals. We conclude that the synthesis of mutant elastin in CL activates multiple downstream disease pathways by triggering a UPR, altered mechanical signaling, increased release of TGFβ and apoptosis. We propose that the combined effects of these processes lead to the development of an emphysematous pulmonary phenotype in CL.

Topics: Animals; Apoptosis; Cutis Laxa; Desmosine; Disease Models, Animal; Elastic Modulus; Elastin; Eukaryotic Initiation Factor-2; Frameshift Mutation; Gene Expression; Genes, Reporter; Genetic Vectors; Green Fluorescent Proteins; Humans; Lung; Mice; Mice, Inbred C57BL; Mice, Transgenic; Phosphorylation; Pulmonary Emphysema; Respiratory Mechanics; Smad2 Protein; Transforming Growth Factor beta; Tropoelastin; Unfolded Protein Response

Peroxisome proliferator-activated receptor-γ (PPARγ) plays an important role in the vasculature; however, the role of PPARγ in abdominal aortic aneurysms (AAA) is not well understood. We hypothesized that PPARγ in smooth muscle cells (SMCs) attenuates the development of AAA. We also investigated PPARγ-mediated signaling pathways that may prevent the development of AAA.. We determined whether periaortic application of CaCl(2) renders vascular SMC-selective PPARγ knockout (SMPG KO) mice more susceptible to destruction of normal aortic wall architecture.. There is evidence of increased vessel dilatation in the abdominal aorta 6 weeks after 0.25M periaortic CaCl(2) application in SMPG KO mice compared with littermate controls (1.4 ± 0.3 mm [n = 8] vs 1.1 ± 0.2 mm [n = 7]; P = .000119). Results from SMPG KO mice indicate medial layer elastin degradation was greater 6 weeks after abluminal application of CaCl(2) to the abdominal aorta (P < .01). Activated cathepsin S, a potent elastin-degrading enzyme, was increased in SMPG KO mice vs wild-type controls. To further identify a role of PPARγ signaling in reducing the development of AAA, we demonstrated that adenoviral-mediated PPARγ overexpression in cultured rat aortic SMCs decreases (P = .022) the messenger RNA levels of cathepsin S. In addition, a chromatin immunoprecipitation assay detected PPARγ bound to a peroxisome proliferator-activated receptor response element (PPRE) -141 to -159 bp upstream of the cathepsin S gene sequence in mouse aortic SMCs. Also, adenoviral-mediated PPARγ overexpression and knockdown in cultured rat aortic SMCs decreases (P = .013) and increases (P = .018) expression of activated cathepsin S. Finally, immunohistochemistry demonstrated a greater inflammatory infiltrate in SMPG KO mouse aortas, as evidenced by elevations in F4/80 and tumor necrosis factor-α expression.. In this study, we identify PPARγ as an important contributor in attenuating the development of aortic aneurysms by demonstrating that loss of PPARγ in vascular SMCs promotes aortic dilatation and elastin degradation. Thus, PPARγ activation may be potentially promising medical therapy in reducing the risk of AAA progression and rupture.

Topics: Animals; Aorta, Abdominal; Aortic Aneurysm, Abdominal; Binding Sites; Calcium Chloride; Cathepsins; Cells, Cultured; Dilatation, Pathologic; Disease Models, Animal; Elastin; Enzyme Activation; Inflammation; Mice; Mice, Knockout; Muscle, Smooth, Vascular; Myocytes, Smooth Muscle; PPAR gamma; Promoter Regions, Genetic; Rats; RNA Interference; RNA, Messenger; Signal Transduction; Time Factors; Transfection

Hypoxic pulmonary hypertension (HPH) causes extralobar pulmonary artery (PA) stiffening, which potentially impairs right ventricular systolic function. Changes in the extracellular matrix proteins collagen and elastin have been suggested to contribute to this arterial stiffening. We hypothesized that vascular collagen accumulation is a major cause of extralobar PA stiffening in HPH and tested our hypothesis with transgenic mice that synthesize collagen type I resistant to collagenase degradation (Col1a1(R/R)). These mice and littermate controls that have normal collagen degradation (Col1a1(+/+)) were exposed to hypoxia for 10 days; some were allowed to recover for 32 days. In vivo PA pressure and isolated PA mechanical properties and collagen and elastin content were measured for all groups. Vasoactive studies were also performed with U-46619, Y-27632, or calcium- and magnesium-free medium. Pulmonary hypertension occurred in both mouse strains due to chronic hypoxia and resolved with recovery. HPH caused significant PA mechanical changes in both mouse strains: circumferential stretch decreased, and mid-to-high-strain circumferential elastic modulus increased (P < 0.05 for both). Impaired collagen type I degradation prevented a return to baseline mechanical properties with recovery and, in fact, led to an increase in the low and mid-to-high-strain moduli compared with hypoxia (P < 0.05 for both). Significant changes in collagen content were found, which tended to follow changes in mid-to-high-strain elastic modulus. No significant changes in elastin content or vasoactivity were observed. Our results demonstrate that collagen content is important to extralobar PA stiffening caused by chronic hypoxia.

Topics: Animals; Biomechanical Phenomena; Blood Pressure; Chronic Disease; Collagen Type I; Collagen Type I, alpha 1 Chain; Disease Models, Animal; Elastic Modulus; Elastin; Hydroxyproline; Hypertension, Pulmonary; Hypoxia; Mechanotransduction, Cellular; Mice; Mice, Transgenic; Mutation; Pulmonary Artery; Recovery of Function; Time Factors; Vasoconstriction; Vasoconstrictor Agents

Elucidating early time courses of biomechanical responses by arteries to altered mechanical stimuli is paramount to understanding and eventually predicting long-term adaptations. In a previous study, we reported marked long-term (at 35-56 days) consequences of increased pulsatile hemodynamics on arterial structure and mechanics. Motivated by those findings, we focus herein on arterial responses over shorter periods (at 7, 10, and 14 days) following placement of a constrictive band on the aortic arch between the innominate and left carotid arteries of wild-type mice, which significantly increases pulsatility in the right carotid artery. We quantified hemodynamics in vivo using noninvasive ultrasound and measured wall properties and composition in vitro using biaxial mechanical testing and standard (immuno)histology. Compared with both baseline carotid arteries and left carotids after banding, right carotids after banding experienced a significant increase in both pulse pressure, which peaked at day 7, and a pulsatility index for velocity, which continued to rise over the 42-day study despite a transient increase in mean flow that peaked at day 7. Wall thickness and inner diameter also increased significantly in the right carotids, both peaking at day 14, with an associated marked early reduction in the in vivo axial stretch and a persistent decrease in smooth muscle contractility. Glycosaminoglycan content also increased within the wall, peaking at day 14, whereas increases in monocyte chemoattractant protein-1 activity and the collagen-to-elastin ratio continued to rise. These findings confirm that pulsatility is an important modulator of wall geometry, structure, and properties but reveal different early time courses for different microscopic and macroscopic metrics, presumably due to the separate degrees of influence of pressure and flow.

Topics: Animals; Biomechanical Phenomena; Blood Pressure; Carotid Artery, Common; Chemokine CCL2; Collagen; Disease Models, Animal; Elasticity; Elastin; Glycosaminoglycans; Hypertension; Immunohistochemistry; Male; Mechanotransduction, Cellular; Mice; Mice, 129 Strain; Mice, Inbred C57BL; Muscle, Smooth, Vascular; Pulsatile Flow; Regional Blood Flow; Time Factors; Ultrasonography

The pathogenesis of aortic aneurysm (AA) is characterized by degradation of extracellular matrix with increased matrix metalloproteinases (MMPs) and inflammatory reaction. Doxycycline (DOXY) has been reported to control the extension of AA by regulation of MMP. However, systemic administration may cause adverse side effects. In this study, we demonstrated the possibility of local administration of DOXY controlled-release biodegradable fiber (DCRBF) for AA in mice. DCRBF was fabricated by biodegradable polymer (polylactic acid; PLA) mixed with DOXY using an electrospinning technique. DCRBF was cocultured with SMCs, macrophages and aortic tissue, and placed on an abdominal aortic aneurysm which induced apolipoprotein E-deficient mice. We evaluated gene and protein expression of proteases, elastin and inflammatory markers. In the presence of DCRBF, MMP-12 was significantly decreased, TGF-β1 and Lox were significantly increased in SMC gene expression, MMP-9 and -12 significantly decreased gene expression of macrophages. The DCRBF preserved elastin content and decreased MMP-2 and -9 in aortic tissue. In addition, IGF-1 and TIMP-1 were significantly increased and IL-6 and TNF-α were significantly decreased with DCRBF in vivo. In conclusion, our results suggested that local administration of DCRBF may become a promising alternative therapeutic strategy for AA.

Topics: Animals; Aorta; Aortic Aneurysm; Biocompatible Materials; Chemokines; Coculture Techniques; Delayed-Action Preparations; Disease Models, Animal; Doxycycline; Elasticity; Elastin; Gene Expression Regulation; Intercellular Signaling Peptides and Proteins; Lactic Acid; Macrophages; Matrix Metalloproteinases; Mice; Mice, Inbred C57BL; Microscopy, Electron, Scanning; Myocytes, Smooth Muscle; Polyesters; Polymers; Tissue Culture Techniques; Tissue Inhibitor of Metalloproteinases

Smoking is the major etiologic factor in COPD, yet the exact underlying pathogenetic mechanisms have not been elucidated. Since a few years, there is mounting evidence that a specific immune response, partly present as an autoimmune response, contributes to the pathogenesis of COPD. Increased levels of anti-Hep-2 epithelial cell and anti-elastin autoantibodies as well as antibodies against airway epithelial and endothelial cells have been observed in COPD patients. Whether the presence of these autoantibodies contributes to the pathogenesis of COPD is unclear.. To test whether induction of autoantibodies against lung matrix proteins can augment the smoke-induced inflammatory response, we immunized mice with a mixture of the lung extracellular matrix (ECM) proteins elastin, collagen, and decorin and exposed them to cigarette smoke for 3 or 6 months. To evaluate whether the immunization was successful, the presence of specific antibodies was assessed in serum, and presence of specific antibody producing cells in spleen and lung homogenates. In addition, the presence of inflammatory cells and cytokines was assessed in lung tissue and emphysema development was evaluated by measuring the mean linear intercept.. We demonstrated that both ECM immunization and smoke exposure induced a humoral immune response against ECM proteins and that ECM immunization itself resulted in increased macrophage numbers in the lung. The specific immune response against ECM proteins did not augment the smoke-induced inflammatory response in our model.. By demonstrating that smoke exposure itself can result in a specific immune response and that presence of this specific immune response is accompanied by an influx of macrophages, we provide support for the involvement of a specific immune response in the smoke-induced inflammatory response as can be seen in patients with COPD.

Topics: Animals; Autoantibodies; Collagen; Cytokines; Decorin; Disease Models, Animal; Elastin; Extracellular Matrix Proteins; Female; Immunization; Lung; Mice; Mice, Inbred C57BL; Pneumonia; Pulmonary Emphysema; Smoking

During arterial aneurysm formation, levels of the membrane-anchored matrix metalloproteinase, MT1-MMP, are elevated dramatically. Although MT1-MMP is expressed predominately by infiltrating macrophages, the roles played by the proteinase in abdominal aortic aneurysm (AAA) formation in vivo remain undefined. Using a newly developed chimeric mouse model of AAA, we now demonstrate that macrophage-derived MT1-MMP plays a dominant role in disease progression. In wild-type mice transplanted with MT1-MMP-null marrow, aneurysm formation induced by the application of CaCl2 to the aortic surface was almost completely ablated. Macrophage infiltration into the aortic media was unaffected by MT1-MMP deletion, and AAA formation could be reconstituted when MT1-MMP+/+ macrophages, but not MT1-MMP+/+ lymphocytes, were infused into MT1-MMP-null marrow recipients. In vitro studies using macrophages isolated from either WT/MT1-MMP-/- chimeric mice, MMP-2-null mice, or MMP-9-null mice demonstrate that MT1-MMP alone plays a dominant role in macrophage-mediated elastolysis. These studies demonstrate that destruction of the elastin fiber network during AAA formation is dependent on macrophage-derived MT1-MMP, which unexpectedly serves as a direct-acting regulator of macrophage proteolytic activity.

Topics: Animals; Aorta; Aortic Aneurysm, Abdominal; Calcium Chloride; Disease Models, Animal; Elastin; Humans; Macrophages; Matrix Metalloproteinase 13; Matrix Metalloproteinase 2; Matrix Metalloproteinase 9; Mice; Mice, Knockout

UVB irradiation has been reported to induce photoaging and suppress systemic immune function that could lead to photocarcinogenesis. However, because of the paucity of an UVB-induced photodamaged skin model, precise and temporal mechanism(s) underlying the deleterious effects of long-term UVB exposure on human skin have yet to be delineated. In this study, we established a model using human skin xenografted onto severe combined immunodeficient mice, which were subsequently challenged by repeated UVB irradiation for 6 weeks. Three-dimensional optical image analysis of skin replicas and noninvasive biophysical measurements illustrated a significant increase in skin surface roughness, similar to premature photoaging, and a significant loss of skin elasticity after long-term UVB exposure. Resembling authentically aged skin, UVB-exposed samples exhibited significant increases in epithelial keratins (K6, K16, K17), elastins, and matrix metalloproteinases (MMP-1, MMP-9, MMP-12) as well as degradation of collagens (I, IV, VII). The UVB-induced deterioration of fibrous keratin intermediate filaments was also observed in the stratum corneum. Additionally, similarities in gene expression patterns between our model and chronologically aged skin substantiated the plausible relationship between photodamage and chronological age. Furthermore, severe skin photodamage was observed when neutralizing antibodies against TIMP-1, an endogenous inhibitor of MMPs, were administered during the UVB exposure regimen. Taken together, these findings suggest that our skin xenograft model recapitulates premature photoaged skin and provides a comprehensive tool with which to assess the deleterious effects of UVB irradiation.

Topics: Adult; Animals; Blotting, Western; Collagen; Dermis; Disease Models, Animal; Elasticity; Elastin; Epidermis; Female; Gene Expression Profiling; Humans; Immunohistochemistry; Keratins; Matrix Metalloproteinases; Mice; Mice, SCID; Microscopy, Electron, Transmission; Middle Aged; Reverse Transcriptase Polymerase Chain Reaction; Skin Aging; Tissue Inhibitor of Metalloproteinase-1; Transplantation, Heterologous; Ultraviolet Rays

Nitric oxide (NO) plays an important role in lung development and perinatal lung function, and pulmonary NO synthases (NOS) are decreased in bronchopulmonary dysplasia (BPD) following preterm birth. Fetal estradiol levels increase during late gestation and estradiol up-regulates NOS, suggesting that after preterm birth estradiol deprivation causes attenuated lung NOS resulting in impaired pulmonary function.. To test the effects of postnatal estradiol administration in a primate model of BPD over 14 days after delivery at 125 days of gestation (term = 185 d).. Cardiopulmonary function was assessed by echocardiography and whole body plethysmography. Lung morphometric and histopathologic analyses were performed, and NOS enzymatic activity and abundance were measured.. Estradiol caused an increase in blood pressure and ductus arteriosus closure. Expiratory resistance and lung compliance were also improved, and this occurred before spontaneous ductal closure. Furthermore, both oxygenation and ventilation indices were improved with estradiol, and the changes in lung function and ventilatory support requirements persisted throughout the study period. Whereas estradiol had negligible effect on indicators of lung inflammation and on lung structure assessed after the initial 14 days of ventilatory support, it caused an increase in lung neuronal and endothelial NOS enzymatic activity.. In a primate model of BPD, postnatal estradiol treatment had favorable cardiovascular impact, enhanced pulmonary function, and lowered requirements for ventilatory support in association with an up-regulation of lung NOS. Estradiol may be an efficacious postnatal therapy to improve lung function and outcome in preterm infants.

Topics: Animals; Animals, Newborn; Blood Pressure; Bronchoalveolar Lavage Fluid; Bronchopulmonary Dysplasia; Disease Models, Animal; Ductus Arteriosus; Elastin; Estradiol; Estrogens; Female; Humans; Infant, Newborn; Lung; Lung Compliance; Male; Nitric Oxide Synthase; Oxygen; Papio; Pulmonary Surfactants; Random Allocation; Receptors, Estradiol; Respiration, Artificial; RNA, Messenger; Up-Regulation

The goal of this study was to develop a surgical method for the creation of vocal fold injuries in mice, as a precursor to the use of genetically engineered mouse models in the study of vocal fold wound healing and scar formation.. Seven FVB strain mice were used in this study. A laryngoscope and 3 micro-instruments were designed and fabricated to facilitate endoscopic vocal fold visualization and the creation of vocal fold surgical injuries. The larynges were harvested 1 and 7 days after surgery, and the vocal fold injury sites were evaluated by routine hematoxylin and eosin staining. Additional immunohistochemical analysis of collagen type I and elastin distribution in the lamina propria was performed for an uninjured control larynx.. Endoscopic visualization and vocal fold stripping resulting in thyroarytenoid muscle exposure were successful in all animals. Histologic and immunohistochemical analyses revealed a simple lamina propria structure with relatively even collagen type I and elastin distribution in the control vocal fold, obliteration of vocal fold mucosa 1 day after surgery, and complete reepithelialization by 7 days.. These results demonstrate the feasibility of creating reproducible vocal fold injuries via an endoscopic approach in mice. The observation that the mouse lamina propria may have a relatively simple histologic structure indicates that additional characterization should be performed and caution used in translating findings between this and other model systems.

Topics: Animals; Cicatrix; Collagen Type I; Disease Models, Animal; Elastin; Follow-Up Studies; Immunohistochemistry; Laryngeal Diseases; Laryngoscopy; Male; Mice; Mice, Inbred Strains; Mucous Membrane; Vocal Cords; Wound Healing

Arteries experience marked variations in blood pressure and flow during the cardiac cycle that can intensify during exercise, in disease, or with aging. Diverse observations increasingly suggest the importance of such pulsatility in arterial homeostasis and adaptations. We used a transverse aortic arch banding model to quantify chronic effects of increased pulsatile pressure and flow on wall morphology, composition, and biaxial mechanical properties in paired mouse arteries: the highly pulsatile right common carotid artery proximal to the band (RCCA-B) and the nearly normal left common carotid artery distal to the band (LCCA-B). Increased pulsatile mechanical stimuli in RCCA-B increased wall thickness compared with LCCA-B, which correlated more strongly with pulse (r* = 0.632; P < 0.01) than mean (r* = 0.020; P = 0.47) or systolic (r* = 0.466; P < 0.05) pressure. Similarly, inner diameter at mean pressure increased in RCCA-B and correlated slightly more strongly with a normalized index of blood velocity pulsatility (r* = 0.915; P < <0.001) than mean flow (r* = 0.834; P < 0.001). Increased wall thickness and luminal diameter in RCCA-B resulted from significant increases in cell number per cross-sectional area (P < 0.001) and collagen-to-elastin ratio (P < 0.05) as well as a moderate (1.7-fold) increase in glycosaminoglycan content, which appears to have contributed to the significant decrease (P < 0.001) in the in-vivo axial stretch in RCCA-B compared with LCCA-B. Changes in RCCA-B also associated with a signficant increase in monocyte chemoattractant protein-1 (P < 0.05) whereas LCCA-B did not. Pulsatile pressure and flow are thus important stimuli in the observed three-dimensional arterial adaptations, and there is a need for increased attention to the roles of both axial wall stress and adventitial remodeling.

Topics: Animals; Aorta, Thoracic; Blood Pressure; Carotid Artery Diseases; Carotid Artery, Common; Chemokine CCL2; Collagen; Disease Models, Animal; Elastin; Heart Rate; Hypertension; Mice; Mice, Inbred C57BL; Pulsatile Flow; Stress, Mechanical

Even though elastin and fibrillin-1 are the major structural components of elastic fibers, mutations in elastin and fibrillin-1 lead to narrowing of large arteries in supravalvular aortic stenosis and dilation of the ascending aorta in Marfan syndrome, respectively. A genetic approach was therefore used here to distinguish the differential contributions of elastin and fibrillin-1 to arterial development and compliance.. Key parameters of cardiovascular function were compared among adult mice haploinsufficient for elastin (Eln(+/-)), fibrillin-1 (Fbn1(+/-)), or both proteins (dHet). Physiological and morphological comparisons correlate elastin haploinsufficiency with increased blood pressure and vessel length and tortuosity in dHet mice, and fibrillin-1 haploinsufficiency with increased aortic diameter in the same mutant animals. Mechanical tests confirm that elastin and fibrillin-1 impart elastic recoil and tensile strength to the aortic wall, respectively. Additional ex vivo analyses demonstrate additive and overlapping contributions of elastin and fibrillin-1 to the material properties of vascular tissues. Lastly, light and electron microscopy evidence implicates fibrillin-1 in the hypertension-promoted remodeling of the elastin-deficient aorta.. These results demonstrate that elastin and fibrillin-1 have both differential and complementary roles in arterial wall formation and function, and advance our knowledge of the structural determinants of vascular physiology and disease.

Topics: Animals; Aortic Stenosis, Supravalvular; Arteries; Biomechanical Phenomena; Compliance; Disease Models, Animal; Elastic Tissue; Elastin; Extracellular Matrix; Fibrillin-1; Fibrillins; Humans; Marfan Syndrome; Mice; Mice, Inbred C57BL; Mice, Mutant Strains; Microfilament Proteins; Phenotype

A cerebral aneurysm (CA) causes catastrophic subarachnoid hemorrhage. Degradation of extracellular matrix in arterial walls is a prominent feature of cerebral aneurysms. We investigated the expression and role of cysteine cathepsins, collagen- and elastin- degrading proteinases, in CA progression.. CAs were induced in Sprague-Dawley rats with or without cysteine cathepsin inhibitor, NC-2300. Expression of cathepsin B, K, S, and cystatin C, an endogenous inhibitor of cysteine cathepsins, in aneurysmal walls was examined in quantitative RT-PCR and immunohistochemistry. The activity of cysteine cathepsins and collagenase I and IV in aneurysmal walls was also assessed. Finally, expression of cysteine cathepsins and cystatin C in human CAs was examined.. Quantitative RT-PCR and immunohistochemistry revealed upregulated expression of cathepsin B, K, and S in the late stage of aneurysm progression. In contrast, cystatin C expression was reduced with aneurysm progression. Treatment with NC-2300 resulted in the decreased incidence of advanced CAs. The activity of cysteine cathepsins and collagenase I and IV in aneurysmal walls was reduced and elastin content was increased in the NC-2300-treated group. Finally, immunohistochemistry for cysteine cathepsins and cystatin C expression in human CAs showed the same expression pattern as in the rat study.. Data obtained by using NC-2300 revealed an important role of cysteine cathepsins in the progression of CAs. Our findings strongly suggest that an imbalance between cysteine cathepsins and their inhibitor may cause the excessive breakdown of extracellular matrix in the arterial walls leading to the progression and rupture of CAs.

Topics: Animals; Brain; Cathepsin B; Cathepsin K; Cathepsins; Cerebral Arteries; Collagenases; Cystatin C; Cystatins; Disease Models, Animal; Disease Progression; Elastin; Enzyme Inhibitors; Epoxy Compounds; Extracellular Matrix; Immunohistochemistry; Intracranial Aneurysm; Male; Rats; Rats, Sprague-Dawley; RNA, Messenger; Subarachnoid Hemorrhage

Persistent endoleak and endotension, complications after endovascular aortic repair, may be caused by an unorganized thrombus inside the aneurysm. The experimental study was designed to evaluate the effectiveness of stent grafts (S/Gs) with slow release of basic fibroblast growth factor (bFGF) for the organization.. The S/Gs were constructed of self-expanding Z stent covered with expanded polytetra fluoroethylene graft, and coated with elastin to be able to bind and slowly release bFGF. Five elastin-coated S/Gs with bFGF (bFGF-S/Gs) and without bFGF (C-S/Gs) were placed in the normal canine aorta respectively. The thoracic aortic aneurysm models were surgically created with a jugular vein patch in 12 beagles. S/Gs with six holes, for creating endoleaks, were used in the experiment of aneurysmal repair. The bFGF-S/Gs (n = 6) and C-S/Gs (n = 6) were implanted. The beagles were sacrificed at two weeks after the endovascular procedure and examined histologically.. The bFGF-S/Gs induced six times the intimal proliferation of the C-S/Gs in normal aorta. Twelve animals had successfully created aneurysms, and had endoleaks just after the endovascular procedure. At two weeks after the endovascular procedure, the percentage of fibrous area in the aneurysmal cavity treated with bFGF-S/G (35.7 +/- 4.3%) was significantly greater than C-S/G (13.6 +/- 2.2%) (P < .01).. bFGF-S/Gs are effective for accelerating organization of the aneurysm cavity and developing neointima. Further research on bFGF-S/Gs would clarify the association of endoleaks.

Topics: Animals; Aorta, Thoracic; Aortic Aneurysm, Thoracic; Blood Vessel Prosthesis Implantation; Cardiovascular Agents; Cell Proliferation; Delayed-Action Preparations; Disease Models, Animal; Dogs; Drug-Eluting Stents; Elastin; Feasibility Studies; Fibroblast Growth Factor 2; Fibrosis; Humans; Polytetrafluoroethylene; Prosthesis Design; Recombinant Proteins; Tunica Intima

Extracellular matrix remodeling has been proposed as one mechanism by which proximal pulmonary arteries stiffen during pulmonary arterial hypertension (PAH). Although some attention has been paid to the role of collagen and metallomatrix proteins in affecting vascular stiffness, much less work has been performed on changes in elastin structure-function relationships in PAH. Such work is warranted, given the importance of elastin as the structural protein primarily responsible for the passive elastic behavior of these conduit arteries. Here, we study structure-function relationships of fresh arterial tissue and purified arterial elastin from the main, left, and right pulmonary artery branches of normotensive and hypoxia-induced pulmonary hypertensive neonatal calves. PAH resulted in an average 81 and 72% increase in stiffness of fresh and digested tissue, respectively. Increase in stiffness appears most attributable to elevated elastic modulus, which increased 46 and 65%, respectively, for fresh and digested tissue. Comparison between fresh and digested tissues shows that, at 35% strain, a minimum of 48% of the arterial load is carried by elastin, and a minimum of 43% of the change in stiffness of arterial tissue is due to the change in elastin stiffness. Analysis of the stress-strain behavior revealed that PAH causes an increase in the strains associated with the physiological pressure range but had no effect on the strain of transition from elastin-dominant to collagen-dominant behavior. These results indicate that mechanobiological adaptations of the continuum and geometric properties of elastin, in response to PAH, significantly elevate the circumferential stiffness of proximal pulmonary arterial tissue.

Topics: Adaptation, Physiological; Animals; Blood Pressure; Cattle; Disease Models, Animal; Elasticity; Elastin; Hyperbaric Oxygenation; Hypertension; Male; Models, Cardiovascular; Protein Conformation; Pulmonary Artery; Stress, Mechanical; Structure-Activity Relationship

All-trans retinoic acid (RA) is a potent modulator of lung development. Chorioamnionitis, which is frequently associated with preterm birth, causes fetal lung inflammation and improves lung function but also results in alveolar simplification and microvascular injury. Endotoxin-mediated chorioamnionitis reduces RA concentration in the fetal lung to 16% of control values. We hypothesized that administration of RA to the fetus before induction of chorioamnionitis would preserve septation of the distal airspaces. Time-mated ewes with singletons were assigned to receive a fetal intramuscular treatment with 20,000 IU of RA in olive oil (or olive oil only) 3 hr prior to intra-amniotic injection of endotoxin (20 mg, E. coli 055:B5) or saline, at 124-day gestational age and 7 days after the fetal treatment. The right cranial lung lobe was processed for morphometric analysis. RA treatment did not affect chorioamnionitis-induced fetal and systemic inflammation or interleukin-8 concentrations in lung tissue. RA administration alone did not alter lung structure. Relative to control lungs (5 +/- 3 mL/kg), lung volume increased similarly with endotoxin (22 +/- 4 mL/kg) or RA plus endotoxin (20 +/- 3 mL/kg; P < 0.05). Alveolar wall thickness was 4.2 +/- 0.3 mum after endotoxin-induced chorioamnionitis, 6.0 +/- 0.4 mum in controls (P < 0.05 versus endotoxin) and 5.5 +/- 0.2 mum after RA and endotoxin (P < 0.05 versus control, n.s. versus endotoxin). The ratio of airspace versus tissue was 4.6 +/- 0.3 in endotoxin-induced chorioamnionitis, 2.1 +/- 0.3 in controls and 4.1 +/- 0.5 after RA and endotoxin. We conclude that fetal treatment with RA did not prevent inflammation-induced alveolar simplification.

Topics: Animals; Bronchopulmonary Dysplasia; Chorioamnionitis; Disease Models, Animal; Elastin; Endotoxins; Female; Fetus; Humans; Infant, Newborn; Interleukin-8; Lung; Pregnancy; Pulmonary Alveoli; Sheep; Tretinoin

To study how the balance between tacrolimus elution and polymer degradation from drug-eluting stents (DES) affects neointimal thickening (NIT) in swine coronary arteries.. We assessed a fast-degrading high dose (2 microg/mm2), a slow degrading low dose (1 microg/mm2) or polymer-only coated DES (Pol) versus bare metal stent (BMS). Coronary segments were pre-injured with a balloon/artery ratio of 1.1 to 1.3. Then stents were implanted at that site with a stent/artery ratio of 1.1, with a follow-up period of 5 to 180 days. Histology showed a well endothelialised neointima (82 +/- 1% in high dose DES vs. 93 +/- 8% in BMS) already at five days, without differences in eNOS expression. Morphometry indicated that neointimal thickness in DES was significantly reduced as compared to BMS and Pol at 28 and 90 days. Polymer degradation products induced a distinct inflammatory response which was effectively suppressed in DES. Between 90 and 180 days, however, the slow degrading low-dose stent showed catch-up of NIT.. Tacrolimus eluted from a biodegradable stent coating can suppress the inflammatory effect of the coating degradation products if the balance between the drug levels and the degradation products is favorable.

Topics: Angioplasty, Balloon, Coronary; Animals; Coated Materials, Biocompatible; Coronary Vessels; Disease Models, Animal; Drug-Eluting Stents; Elastin; Endothelium, Vascular; Immunohistochemistry; Immunosuppressive Agents; Lactic Acid; Metals; Nitric Oxide Synthase Type III; Polyglycolic Acid; Polylactic Acid-Polyglycolic Acid Copolymer; Sus scrofa; Swine; Swine, Miniature; Tacrolimus; Tunica Intima; Tunica Media; Vasculitis

This study was undertaken to establish a Peyronie's disease model with penile curvature by using recombinant transforming growth factor-beta1 (TGF-beta1) protein or adenovirus (ad-TGF-beta1). Four-month-old male Sprague-Dawley rats were divided into seven groups (n = 18 per group): G1 received a single injection of saline into the tunica albuginea (0.1 mL); G2, repeated injections of ad-LacZ (days 0, 3, and 6; 1 x 10(10) particles/0.1 mL respectively); G3, a single injection of recombinant TGF-beta1 protein (700 ng/0.1 mL); G4, repeated injections of recombinant TGF-beta1 protein (days 0, 3 and 6; 700 ng/0.1 mL respectively); G5, a single injection of low-dose ad-TGF-beta1 (1 x 10(10) particles/0.1 mL); G 6, a single injection of high-dose ad-TGF-beta1 (3 x 10(10) particles/0.1 mL); and G7, repeated injections of low-dose ad-TGF-beta1 (days 0, 3, and 6; 1 x 10(10) particles/0.1 mL respectively). Penile curvature was evaluated 30, 45 and 60 days after treatment, and the penis was then harvested for histological examination. Repeated injection of low-dose ad-TGF-beta1 not only induced fibrous scar in the tunica, which lasted up to 60 days after injection, but also resulted in significant penile curvature by artificial erection test 45 days after treatment. A peculiar histological finding in this group was trapping of inflammatory cells in the tunica, subsequent fibrosis, and formation of cartilage and calcification as well as loss of elastin fibres. This model involving repeated injection of ad-TGF-beta1 may contribute to further investigation of the pathogenesis of Peyronie's disease and the development of new therapeutics targeting this pathway.

Topics: Adenoviridae; Animals; Calcinosis; Cartilage; Disease Models, Animal; Disease Progression; Elastin; Fibrosis; Gene Transfer Techniques; Genetic Vectors; Injections; Male; Penile Erection; Penile Induration; Penis; Rats; Rats, Sprague-Dawley; Recombinant Proteins; Swine; Time Factors; Transforming Growth Factor beta1

Expansive vascular remodeling is considered a feature of vulnerable plaques. Although inflammation is upregulated in the media and adventitia of atherosclerotic lesions, its contribution to expansive remodeling is unclear. We investigated this issue in injured femoral arteries of normo- and hyperlipidemic rabbits fed with a conventional (CD group; n=20) or a 0.5% cholesterol (ChD group; n=20) diet. Four weeks after balloon injury of the femoral arteries, we examined vascular wall alterations, localization of macrophages and matrix metalloproteases (MMP)-1, -2, -9, and extracellular matrix. Neointimal formation with luminal stenosis was evident in both groups, while expansive remodeling was observed only in the ChD group. Areas immunopositive for macrophages, MMP-1, -2 and -9 were larger not only in the neointima, but also in the media and/or adventitia in the injured arterial walls of the ChD, than in the CD group. Areas containing smooth muscle cells (SMCs), elastin and collagen were smaller in the injured arterial walls of the ChD group. MMP-1, -2 and -9 were mainly localized in infiltrating macrophages. MMP-2 was also found in SMCs and adventitial fibroblasts. Vasa vasorum density was significantly increased in injured arteries of ChD group than in those of CD group. These results suggest that macrophages in the media and adventitia play an important role in expansive atherosclerotic remodeling via extracellular matrix degradation and SMC reduction.

Topics: Animals; Atherosclerosis; Biomarkers; Catheterization; Cholesterol, Dietary; Collagen; Connective Tissue; Disease Models, Animal; Elastin; Extracellular Matrix; Femoral Artery; Macrophages; Male; Metalloproteases; Muscle, Smooth, Vascular; Myocytes, Smooth Muscle; Rabbits; Tunica Intima; Tunica Media

Hypoxia impairs normal neonatal pulmonary artery remodeling and alveolar development. Matrix metalloproteinase-2 (MMP-2), which regulates collagen breakdown, is important during development. Our objective was to test the hypothesis that hypoxia attenuates the normal postnatal increase in MMP-2 and evaluate alveolar development and pulmonary arterial remodeling in Mmp2 mice. C57BL/6 wild-type (WT), Mmp2, Mmp2, and MMP-inhibited (with doxycycline) mice were exposed to hypoxia (12% O2) or air from birth to 2 wk of age. Pulmonary arterial remodeling, alveolar development, and vascular collagen and elastin were evaluated. MMP-2 was estimated by quantitative real-time polymerase chain reaction, enzyme-linked immunosorbent assay, immunohistochemistry, and zymography. We observed that 1) in WT mice, hypoxia led to thicker-walled pulmonary arteries and impaired alveolarization, accompanied by decreased MMP-2 and increased tissue inhibitor of metalloproteinases-2 (TIMP-2); 2) Mmp2 mice in air had thicker-walled arteries, impaired alveolarization, and increased perivascular collagen and elastin compared with WT; 3) hypoxia further inhibited alveolarization but did not alter arterial thickening in Mmp2 mice. Mmp2 and MMP-inhibited mice also had thicker-walled arteries than WT in air, but alveolarization was not different. We conclude that hypoxia reduces the postnatal MMP-2 increase in the lung, which may contribute to abnormal pulmonary arterial remodeling and impaired alveolarization.

Topics: Animals; Animals, Newborn; Collagen; Disease Models, Animal; Down-Regulation; Doxycycline; Elastin; Gene Expression Regulation, Enzymologic; Hypoxia; Lung; Matrix Metalloproteinase 2; Matrix Metalloproteinase Inhibitors; Mice; Mice, Inbred C57BL; Mice, Knockout; Mice, Transgenic; Protease Inhibitors; Pulmonary Alveoli; Pulmonary Artery; RNA, Messenger; Time Factors; Tissue Inhibitor of Metalloproteinase-2

Very-low-density lipoprotein receptor (VLDLR) in knockout mice (vldlr(-/-)) has been reported to induce subretinal neovascularization. Therefore, VLDLR expression in the wild-type mouse retina was investigated and the retinal angiogenic process in vldlr(-/-) mice was characterized.. VLDLR expression in the retina and in purified retinal vascular endothelial cells (RECs) and retinal pigment epithelial (RPE) cells was determined by reverse transcription-polymerase chain reaction (RT-PCR) and immunohistochemistry. Angiogenic evolution in vldlr(-/-) mice was examined by fundus fluorescein angiography, histology, double-staining of FITC-dextran perfusion and elastin immunohistochemistry, isolectin staining, and confocal fluorescence microscopy.. VLDLR mRNA was detected in the wild-type mouse retina and in purified RECs and RPE cells. The VLDLR protein was localized in the RPE layer, vessels in the ganglion cell layer, and around the outer limiting membrane of the retina. The retinal pathogenic process in vldlr(-/-) mice recapitulates key features of retinal angiomatous proliferation (RAP) in humans, a subtype of neovascular age-related macular degeneration (AMD). These include neovascular growth originating from retinal vessels and progressing to the subretinal space with intraretinal, subretinal, and choroidal angiogenic stages, RPE disruption and Bruch membrane exposure, retinal-choroidal anastomosis, subsequent photoreceptor degeneration, RPE hyperplasia, and subretinal fibrosis at the end stage.. VLDLR is expressed in the wild-type mouse retina, especially in RECs and RPE cells. The vldlr(-/-) mouse exhibits histologic and angiographic characteristics of RAP and is a reproducible animal model facilitating studies of the molecular mechanisms of RAP.

Topics: Animals; Disease Models, Animal; Elastin; Endothelium, Vascular; Female; Fluorescein Angiography; Fluorescent Antibody Technique, Indirect; Gene Expression; Gene Silencing; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Microscopy, Confocal; Pigment Epithelium of Eye; Receptors, LDL; Retina; Retinal Neovascularization; Retinal Vessels; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger

Isolated systolic hypertension is associated with increased elastase activity, vascular calcification, and vascular stiffness. We sought to determine the importance of elastase activity and matrix degradation in the development of elastocalcinosis.. Elastocalcinosis was induced in vivo and ex vivo using warfarin. Hemodynamic parameters, calcium deposition, elastin degradation, transforming growth factor (TGF)-beta signaling, and elastase activity were evaluated at different time points in the in vivo model. Metalloproteinases, serine proteases, and cysteine proteases were blocked to measure their relative implication in elastin degradation. Gradual elastocalcinosis was obtained, and paralleled the elastin degradation pattern. Matrix metalloproteinase (MMP)-9 activity was increased at 5 days of warfarin treatment, whereas TGF-beta signaling was increased at 7 days. Calcification was significantly elevated after 21 days. Blocking metalloproteinases activation with doxycycline and TGF-beta signaling with SB-431542 were able to prevent calcification.. Early MMP-9 activation precedes the increase of TGF-beta signaling, and overt vascular elastocalcinosis and stiffness. Modulation of matrix degradation could represent a novel therapeutic avenue to prevent the gradual age-related stiffening of large arteries, leading to isolated systolic hypertension.

Topics: Animals; Aorta, Abdominal; Calcinosis; Collagen; Disease Models, Animal; Durapatite; Elastin; Femoral Artery; Male; Matrix Metalloproteinase 9; Osteopontin; Rats; Rats, Wistar; Signal Transduction; Transforming Growth Factor beta; Vascular Diseases; Warfarin

Kawasaki disease (KD) is a multisystem vasculitis leading to damage in the coronary circulation and aneurysm formation. Because cardiac tissue from affected children is not available, investigation of the mechanisms responsible for coronary artery damage in KD requires use of a disease model. The present study was undertaken to examine, in an experimental model, the role of matrix metalloproteinase 9 (MMP-9) on coronary artery inflammation and vascular damage.. C57BL/6 mice were injected with Lactobacillus casei cell wall extract to induce coronary arteritis. Hearts were isolated and assayed for MMP-9 protein expression and enzymatic activity by immunoblotting or confocal microscopy and zymography, respectively. MMP-9-deficient mice were used to examine the necessity of MMP-9 for disease development.. Localized inflammation at the coronary artery led to elastin breakdown and aneurysm formation. This occurred in the absence of smooth muscle cell apoptosis. Following disease induction, there was an increase in the amount and enzymatic activity of MMP-9, an elastolytic protease. MMP-9 was up-regulated by tumor necrosis factor alpha (TNFalpha) and produced primarily by vascular smooth muscle cells. In MMP-9-deficient animals, vascular inflammation continued to develop, but the incidence of elastin breakdown was significantly reduced. Elastin breakdown in the coronary artery was virtually eliminated by ablation of MMP-9.. These findings show that TNFalpha up-regulates expression of MMP-9, an important proteinase responsible for extracellular matrix breakdown, leading to coronary artery damage in this model of KD. These results have important implications regarding treatments for improving coronary outcome in affected children.

Topics: Animals; Apoptosis; Bacterial Proteins; Coronary Artery Disease; Coronary Vessels; Disease Models, Animal; Elasticity; Elastin; Gene Expression Regulation, Enzymologic; Lacticaseibacillus casei; Matrix Metalloproteinase 9; Mice; Mice, Inbred C57BL; Mice, Knockout; Mucocutaneous Lymph Node Syndrome; Muscle, Smooth, Vascular; Tumor Necrosis Factor-alpha

The number of men with type II diabetes-associated erectile dysfunction (ED) continues to grow rapidly; however, the majority of basic science studies has examined mechanisms of ED in animal models of type I diabetes. In this study, we first establish an in vivo mouse model of type II diabetic ED using the leptin receptor mutated db/db and wild-type control BKS mouse. Furthermore, we hypothesized that dual mechanistic impairments contribute to the impaired erectile function in the type II diabetic mouse, altered vasoreactivity, and venoocclusive disorder. In vivo erectile function was measured as intracavernosal pressure (ICP) normalized to mean arterial pressure (MAP) following electrical stimulation of the cavernosal nerve. Venoocclusion was assessed by the maintenance of elevated in vivo ICP following intracorporal saline infusion. Vasoreactivity of isolated cavernosum in response to contractile and dilatory stimulation was examined in vitro by myography. Collagen and elastin content were evaluated by quantification of hydroxyproline and desmosine, respectively, as well as by quantitative PCR and histological analysis of isolated cavernosum. Erectile function was significantly decreased in db/db vs. BKS mice in a manner consistent with impairments in venoocclusive ability and decreased inflow. Heightened vasoconstriction and attenuated dilation in cavernosum of db/db vs. BKS mice suggest an overall lowered relaxation ability and thus impaired filling of the cavernosal spaces. A decrease in desmosine and hydroxyproline as well as lowered mRNA levels for tropoelastin, fibrillin-1, and alpha1(I) collagen were detected. These vasoreactive and sinusoidal matrix alterations may alter tissue compliance dispensability, preventing the normal expansion necessary for erection.

Topics: Acetylcholine; Animals; Blood Glucose; Blood Pressure; Body Weight; Collagen; Desmosine; Diabetes Mellitus, Type 2; Disease Models, Animal; Elastin; Electric Stimulation; Erectile Dysfunction; Extracellular Matrix; Hydroxyproline; Male; Mice; Mice, Inbred C57BL; Mice, Mutant Strains; Myography; Organ Size; Penis; Phenylephrine; Polymerase Chain Reaction; Receptors, Leptin; Regional Blood Flow; RNA, Messenger; Vasoconstriction; Vasoconstrictor Agents; Vasodilation; Vasodilator Agents; Veins

Collagens are abundant within the atherosclerotic plaque, where they contribute to lesion volume and mechanical stability and influence cell signaling. The discoidin domain receptor 1 (DDR1), a receptor tyrosine kinase that binds to collagen, is expressed in blood vessels, but evidence for a functional role during atherogenesis is incomplete. In the present study, we generated Ddr1(+/+);Ldlr(-/-) and Ddr1(-/-);Ldlr(-/-) mice and fed them an atherogenic diet for 12 or 24 weeks. Targeted deletion of Ddr1 resulted in a 50% to 60% reduction in atherosclerotic lesion area in the descending aorta at both 12 and 24 weeks. Ddr1(-/-);Ldlr(-/-) plaques exhibited accelerated deposition of fibrillar collagen and elastin at 12 weeks compared with Ddr1(+/+);Ldlr(-/-) plaques. Expression analysis of laser microdissected lesions in vivo, and of Ddr1(-/-) smooth muscle cells in vitro, revealed increased mRNA levels for procollagen alpha1(I) and alpha1(III) and tropoelastin, suggesting an enhancement of matrix synthesis in the absence of DDR1. Furthermore, whereas plaque smooth muscle cell content was unchanged, Ddr1(-/-);Ldlr(-/-) plaques had a 49% decrease in macrophage content at 12 weeks, with a concomitant reduction of in situ gelatinolytic activity. Moreover, mRNA expression of both monocyte chemoattractant protein-1 and vascular cell adhesion molecule-1 was reduced in vivo, and Ddr1(-/-);Ldlr(-/-) macrophages demonstrated impaired matrix metalloproteinase expression in vitro. These data suggest novel roles for DDR1 in macrophage recruitment and invasion during atherogenesis. In conclusion, our data support a role for DDR1 in the regulation of both inflammation and fibrosis early in plaque development. Deletion of DDR1 attenuated atherogenesis and resulted in the formation of matrix-rich plaques.

Topics: Animals; Aorta, Thoracic; Atherosclerosis; Chemokine CCL2; Collagen; Diet, Atherogenic; Discoidin Domain Receptors; Disease Models, Animal; Elastin; Extracellular Matrix; Female; Fibrosis; Lipids; Macrophages; Male; Mice; Mice, Mutant Strains; Muscle, Smooth, Vascular; Mutagenesis; Receptor Protein-Tyrosine Kinases; Receptors, LDL; Receptors, Mitogen; Vascular Cell Adhesion Molecule-1; Vasculitis

Female pelvic floor dysfunction (FPFD) is a complex group of conditions that include urinary incontinence and pelvic organ prolapse (POP). In humans, elastin homeostasis has been implicated in the pathophysiology of FPFD. Lysyl oxidase-like 1 knockout (LOXL1-KO) mice demonstrate abnormal elastic fiber homeostasis and develop FPFD after parturition. We compared the lower urogenital tract (LUT) anatomy and function in LOXL1-KO mice with and without POP. LUT anatomy was assessed in LOXL1-KO mice over 28 wk. Pelvic visceral anatomy in LOXL1-KO was evaluated with a 7-Tesla magnetic resonance imaging (MRI) scanner. LUT function was assessed using conscious cystometry and leak point pressure (LPP) testing. Quantitative histological analysis of elastic fibers was performed on external urethral sphincter (EUS) cross sections. By 25 wk of age, 50% of parous LOXL1-KO mice developed POP. LOXL1-KO mice with POP had greater variability in the size and location of the bladder on MRI compared with mice without POP. Parity and POP were associated with lower LPP. Elastin clusters were significantly increased in the EUS of LOXL1-KO mice with POP. Because parity triggers POP in LOXL1-KO mice, LOXL1-KO mice with POP have variable internal pelvic anatomy, and both parity and POP are associated with a decrease in LPP, we conclude that LOXL1 LUT anatomical and functional phenotype resembles FPFD in humans. The increase in elastin clusters in the urethra of LOXL1-KO mice with POP suggests that elastin disorganization may lead to functional abnormalities. We conclude that LOXL1 warrants further investigation in the pathphysiology of FPFD.

Topics: Amino Acid Oxidoreductases; Animals; Disease Models, Animal; Elastin; Female; Homeostasis; Magnetic Resonance Imaging; Mice; Mice, Knockout; Pelvic Floor; Phenotype; Urethra; Urinary Bladder; Urinary Incontinence; Urogenital System; Uterine Prolapse

Pulmonary inflammation and increased production of the inflammatory cytokine IL-1beta are associated with the development of bronchopulmonary dysplasia (BPD) in premature infants. To study the actions of IL-1beta in the fetal and newborn lung in vivo, we developed a bitransgenic mouse in which IL-1beta is expressed under conditional control in airway epithelial cells. Perinatal pulmonary expression of IL-1beta caused respiratory insufficiency that was associated with increased postnatal mortality. While intrauterine growth of IL-1beta-expressing mice was normal, their postnatal growth was impaired. IL-1beta disrupted alveolar septation and caused abnormalities in alpha-smooth muscle actin and elastin deposition in the septa of distal airspaces. IL-1beta disturbed capillary development and inhibited the production of vascular endothelial growth factor in the lungs of infant mice. IL-1beta induced the expression of CXC chemokines KC (CXCL1) and macrophage inflammatory protein-2 (CXCL2) and of CC chemokines monocyte chemotactic protein (MCP)-1 (CCL2) and MCP-3 (CCL7), consistent with neutrophilic and monocytic infiltration of the lungs. IL-1beta caused goblet cell metaplasia and bronchial smooth muscle hyperplasia. Perinatal expression of IL-1beta in epithelial cells of the lung caused a lung disease that was clinically and histologically similar to BPD.

Topics: Actins; Animals; Animals, Newborn; Bronchopulmonary Dysplasia; Chemokine CCL2; Chemokine CCL7; Chemokine CXCL1; Chemokines, CXC; Disease Models, Animal; Elastin; Epithelial Cells; Humans; Infant, Newborn; Interleukin-1beta; Lung; Mice; Mice, Transgenic; Monocyte Chemoattractant Proteins; Vascular Endothelial Growth Factor A

White carneau (WC) pigeons develop spontaneous atherosclerosis in contrast to atherosclerosis-resistant show racer (SR) pigeons. In this study, cellular and extracellular components and smooth muscle cell (SMC) proliferation rates of specific aortic sites were assessed in both breeds of pigeons prior to lesion development. The atherosclerosis-susceptible site of the WC aorta was characterized by larger lumen diameter without accompanying increase in wall thickness, as well as by SMC hypocellularity, increased proteoglycan content and higher elastin content. For both breeds, cells derived from the lesion site had lower proliferation rates compared to proximal aortic control sites. WC cells had greater proliferation rates than SR cells (109% greater at the atherosclerosis-prone site and 133% greater at the control site). Fibroblast growth factor (FGF) increased the proliferation of WC lesion site cells compared to SR cells (79% vs. 35%); whereas, transforming growth factor beta (TGFbeta) reduced growth in SR but not in WC cells. Differences in hemodynamic properties, in cell-matrix, elastin, proteoglycan and proliferation rates of cells and responses to FGF and TGFbeta in cells of the atherosclerosis-prone area have been identified as potential contributors to the enhanced atherosclerosis potential of this site in WC pigeons.

Topics: Animals; Aorta; Atherosclerosis; Cell Count; Cell Proliferation; Cells, Cultured; Columbidae; Disease Models, Animal; Disease Susceptibility; Elastin; Fibroblast Growth Factors; Humans; Muscle, Smooth, Vascular; Proteoglycans; Recombinant Proteins; Transforming Growth Factor beta

Cigarette smoking is the strongest risk factor for emphysema. However, sensitivity to cigarette smoke-induced emphysema is highly variable, and numerous genetic and environmental factors are thought to mitigate lung response to injury. We report that the quantity of functional elastin in the lung is an important modifier of both lung development and response to injury. In mice with low levels of elastin, lung development is adversely affected, and mice manifest with congenital emphysema. Animals with intermediate elastin levels exhibit normal alveolar structure but develop worse emphysema than normal mice following cigarette smoke exposure. Mechanical testing demonstrates that lungs with low levels of elastin experience greater tissue strains for any given tissue stress compared with wild-type lungs, implying that force-mediated propagation of lung injury through alveolar wall failure may worsen the emphysema after an initial enzymatic insult. Our findings suggest that quantitative deficiencies in elastin predispose to smoke-induce emphysema in animal models and suggest that humans with altered levels of functional elastin could have relatively normal lung function while being more susceptible to smoke-induced lung injury.

Topics: Animals; Disease Models, Animal; Elastin; Female; Genetic Predisposition to Disease; Humans; Immunoenzyme Techniques; Lung; Male; Mice; Mice, Knockout; Mice, Transgenic; Pulmonary Alveoli; Pulmonary Emphysema; Smoke

Lung hypoplasia in congenital diaphragmatic hernia (CDH) seems to involve impaired alveolar septation. We hypothesized that disturbed deposition of elastin and expression of fibroblast growth factor 18 (FGF18), an elastogenesis stimulus, occurs in CDH.. To document FGF18 and elastin in human CDH and ovine surgical and rat nitrofen models and to use models to evaluate the benefit of treatments.. Human CDH and control lungs were collected post mortem. Diaphragmatic hernia was created in sheep at 85 days; fetal lungs were collected at 139 days (term = 145 days). Pregnant rats received nitrofen at 12 days; fetal lungs were collected at 21 days (term = 22 days). Some of the sheep fetuses with hernia underwent tracheal occlusion (TO); some of the nitrofen-treated pregnant rats received vitamin A. Both treatments are known to promote lung growth.. Coincidental with the onset of secondary septation, FGF18 protein increased threefold in control human lungs, which failed to occur in CDH. FGF18 labeling was found in interstitial cells of septa. Elastin staining demonstrated poor septation and markedly decreased elastin density in CDH lungs. Consistently, lung FGF18 transcripts were diminished 60 and 83% by CDH in sheep and rats, respectively, and elastin density and expression were diminished. TO and vitamin A restored FGF18 and elastin expression in sheep and rats, respectively. TO restored elastin density.. Impaired septation in CDH is associated with decreased FGF18 expression and elastic fiber deposition. Simultaneous correction of FGF18 and elastin defects by TO and vitamin A suggests that defective elastogenesis may result, at least partly, from FGF18 deficiency.

Topics: Amino Acid Sequence; Animals; Base Sequence; Disease Models, Animal; Elastin; Female; Fibroblast Growth Factors; Hernia, Diaphragmatic; Humans; Infant; Infant, Newborn; Lung; Male; Molecular Sequence Data; Pulmonary Alveoli; Rats; Rats, Wistar; RNA, Messenger; Sheep; Trachea; Vitamin A

Despite extensive strides in understanding pressure overload induced heart failure, there is very little known about oxidative stress induced matrix metalloproteinase (MMP) activation, collagen degradation and remodeling in pressure overload heart failure. We hypothesize that pressure overload leads to redox imbalance causing increased expression/activity of MMP-2/9 producing collagen degradation and heart failure. To test this hypothesis, we created pressure overload heart failure by abdominal aortic stenosis (AS) in wild-type C57BL/6J and collagen mutant (Col1a1 with 129 s background) mice. At 4 weeks, post surgery, functional parameters were measured. Left ventricle (LV) tissue sections were analyzed by histology, Western Blot and PCR. The results suggest an increase in iNOS with a decrease in eNOS, an increase in nitrated protein modification and depletion of antioxidants thioredoxin and SOD in pressure overload. MMP-2/9 expression/activity and collagen degradation were increased in the AS animals. To determine whether a mutation in the collagen gene at the site of MMP cleavage mitigates cardiac hypertrophy, we used Col1a1 mice. In these mice, the AS induced LV hypertrophy (LVH) was ameliorated. In conclusion, our results suggest that AS leads to increased oxidative stress, expression/activity of MMP-2/9 and a decrease in antioxidant expression producing collagen degradation and heart failure.

Topics: Analysis of Variance; Animals; Aortic Valve Stenosis; Blood Pressure; Blotting, Western; Chronic Disease; Collagen; Disease Models, Animal; Echocardiography; Elastin; Electrocardiography; Enzyme Activation; Heart Failure; Hypertrophy, Left Ventricular; Male; Matrix Metalloproteinase 2; Matrix Metalloproteinase 9; Mice; Mice, Inbred C57BL; Mice, Mutant Strains; Nitric Oxide Synthase Type II; Nitric Oxide Synthase Type III; Oxidative Stress; Research Design; Reverse Transcriptase Polymerase Chain Reaction; Stroke Volume; Ventricular Dysfunction, Left

Maintaining the integrity of arterial elastin is vital for the prevention of abdominal aortic aneurysm (AAA) development. We hypothesized that in vivo stabilization of aortic elastin with pentagalloyl glucose (PGG), an elastin-binding polyphenol, would interfere with AAA development.. Safety and efficacy of PGG treatment were first tested in vitro using cytotoxicity, elastin stability, and PGG-elastin interaction assays. For in vivo studies, the efficacy of PGG was evaluated within a well-established AAA model in rats on the basis of CaCl2-mediated aortic injury. With this model, PGG was delivered periadventitially at 2 separate time points during the course of AAA development; aortic diameter, elastin integrity, and other pathological aspects were monitored and evaluated in PGG-treated aortas compared with saline-treated control aortas. Our results show that a one-time periadventitial delivery of noncytotoxic levels of PGG inhibits elastin degeneration, attenuates aneurysmal expansion, and hinders AAA development in rats without interfering with the pathogenic mechanisms typical of this model, namely inflammation, calcification, and high metalloproteinase activities. PGG binds specifically to arterial elastin and, in doing so, preserves the integrity of elastic lamellae despite the presence of high levels of proteinases derived from inflammatory cells.. Periadventitial administration of PGG hinders the development of AAA in a clinically relevant animal model. Stabilization of aortic elastin in aneurysm-prone arterial segments offers great potential toward the development of safe and effective therapies for AAAs.

Topics: Administration, Topical; Animals; Aorta, Abdominal; Aortic Aneurysm, Abdominal; Calcinosis; Calcium Chloride; Cells, Cultured; Disease Models, Animal; Disease Progression; Drug Evaluation, Preclinical; Elastin; Fibroblasts; Hydrolyzable Tannins; Male; Matrix Metalloproteinase 2; Matrix Metalloproteinase 9; Muscle, Smooth, Vascular; Myocytes, Smooth Muscle; Protein Denaturation; Rats; Rats, Sprague-Dawley

To evaluate the effects of experimental oligohydramnios on lung growth, expression of platelet-derived growth factor (PDGF) and its receptors, and lung morphology in fetal rats.. On day 16 of gestation, we anesthetized timed pregnant Sprague-Dawley dams and punctured uterine wall and fetal membranes of each uterine sac which resulted in oligohydramnios. The fetuses in the opposite uterine horn served as controls. On days 19 and 21 of gestation, the fetuses were delivered by cesarean section and weighed, and the lungs were dissected free and weighed.. Rats exposed to oligohydramnios exhibited significantly lower lung/body weight ratios on days 19 and 21 of gestation and significantly lower radial saccular counts on day 21 of gestation than did the control rats. Lung PDGF-A and PDGF-B gene and protein expression and elastin level were significantly decreased in rats exposed to oligohydramnios on days 19 and 21 of gestation. The PDGF receptor alpha and beta gene expression levels were significantly decreased in rats exposed to oligohydramnios on day 19 of gestation.. A decreased PDGF expression may be important in the pathogenesis of oligohydramnios-induced pulmonary hypoplasia and suggests that supplementation may provide useful therapeutic strategies.

Topics: Animals; Blotting, Western; Disease Models, Animal; Elastin; Female; Fetal Organ Maturity; Fetal Weight; Gene Expression Regulation, Developmental; Gestational Age; Immunoenzyme Techniques; Lung; Oligohydramnios; Organ Size; Platelet-Derived Growth Factor; Pregnancy; Proto-Oncogene Proteins c-sis; Rats; Rats, Sprague-Dawley; RNA, Messenger

Thin-slice videomicroscopy was used to examine the kinetics of constriction in small airways in situ. Balb/C mice inhaled elastase (0-20 IU), and were then left to recover for 14 days before euthanisation and lung removal. Cholinergic responsiveness was assessed in thin lung slices. Magnitude and velocity of narrowing in response to 10(-5) M acetylcholine (ACh), as well as the full concentration-response relationship for ACh (10(-8)-10(-5) M) were assessed. In vivo exposure to elastase was accompanied by statistically significantly decreased magnitudes and velocities of contraction, but no change in the ACh concentration-response relationship. Conversely, overnight, in vitro exposure of slices from control animals to elastase (2.5 microg.mL(-1)) resulted in increased magnitudes and velocities of airway narrowing, with impaired relaxation, as well as marked tearing of the airways from the surrounding parenchyma. These changes are characteristic of decreased tethering forces on the airway wall. Thus, the lung slice technique coupled with videomicroscopic analysis of airway contraction velocities provides a powerful tool to study airway-parenchymal interactions. The elastolytic model of emphysema, which manifests with airspace enlargement and loss of parenchymal attachments, is accompanied by decreased airway contraction kinetics. The mechanism(s) underlying this loss of function remain to be elucidated.

Topics: Acetylcholine; Animals; Bronchoconstriction; Collagen; Disease Models, Animal; Elastin; Female; In Vitro Techniques; Kinetics; Lung; Mice; Mice, Inbred BALB C; Microscopy, Video; Muscle, Smooth; Pancreatic Elastase; Pulmonary Emphysema; Receptors, Cholinergic; Trachea

Increased numbers of T lymphocytes are observed in the lungs of patients with chronic obstructive pulmonary disease, but their role in the disease process is not known. We investigated the role of CD8+ T cells in inflammatory cell recruitment and lung destruction in a cigarette smoke-induced murine model of emphysema. In contrast to wild-type C57BL/6J mice that displayed macrophage, lymphocyte, and neutrophil recruitment to the lung followed by emphysema in response to cigarette smoke, CD8+ T cell-deficient (CD8-/-) mice had a blunted inflammatory response and did not develop emphysema when exposed to long-term cigarette smoke. Further studies supported a pathogenetic pathway whereby the CD8+ T cell product, IFN-gamma-inducible protein-10, induces production of macrophage elastase (matrix metalloproteinase 12) that degrades elastin, both causing lung destruction directly and generating elastin fragments that serve as monocyte chemokines augmenting macrophage-mediated lung destruction. These studies demonstrate a requirement for CD8+ T cells for the development of cigarette smoke-induced emphysema and they provide a unifying pathway whereby CD8+ T cells are a central regulator of the inflammatory network in chronic obstructive pulmonary disease.

Topics: Animals; CD4-Positive T-Lymphocytes; CD8-Positive T-Lymphocytes; Chemotaxis, Leukocyte; Disease Models, Animal; Elastin; Lung; Matrix Metalloproteinase 12; Mice; Mice, Inbred Strains; Monocytes; Nicotiana; Pneumonia; Pulmonary Emphysema; Smoke

Myofibroblasts derived from portal fibroblasts are important fibrogenic cells in the early stages of biliary fibrosis. In contrast to hepatic stellate cells, portal fibroblasts have not been well studied in vitro, and little is known about their myofibroblastic differentiation. In this article we report the isolation and characterization of rat portal fibroblasts in culture. We demonstrate that primary portal fibroblasts undergo differentiation to alpha-smooth muscle actin-expressing myofibroblasts over 10-14 days. Marker analysis comparing portal fibroblasts to hepatic stellate cells demonstrated that these are distinct populations and that staining with elastin and desmin can differentiate between them. Portal fibroblasts expressed elastin at all stages in culture but never expressed desmin, whereas hepatic stellate cells consistently expressed desmin but never elastin. Immunostaining of rat liver tissue confirmed these results in vivo. Characterization of portal fibroblast differentiation in culture demonstrated that these cells required transforming growth factor-beta (TGF-beta): cells remained quiescent in the presence of a TGF-beta receptor kinase inhibitor, whereas exogenous TGF-beta1 enhanced portal fibroblast alpha-smooth muscle actin expression and stress fiber formation. In contrast, platelet-derived growth factor inhibited myofibroblastic differentiation. Portal fibroblasts were also dependent on mechanical tension for myofibroblastic differentiation, and cells cultured on polyacrylamide supports of variable stiffness demonstrated an increasingly myofibroblastic phenotype as stiffness increased.. Portal fibroblasts are morphologically and functionally distinct from hepatic stellate cells. Portal fibroblast myofibroblastic differentiation can be modeled in culture and requires both TGF-beta and mechanical tension.

Topics: Actins; Animals; Biomechanical Phenomena; Cell Adhesion; Cell Differentiation; Cell Proliferation; Cells, Cultured; Disease Models, Animal; Elastin; Fibroblasts; Hepatocytes; Liver Cirrhosis; Male; Platelet-Derived Growth Factor; Rats; Rats, Sprague-Dawley; Transforming Growth Factor beta1; Vitamin A

Diseases linked to the elastin gene arise from loss-of-function mutations leading to protein insufficiency (supravalvular aortic stenosis) or from missense mutations that alter the properties of the elastin protein (dominant cutis laxa). Modeling these diseases in mice is problematic because of structural differences between the human and mouse genes. To address this problem, we developed a humanized elastin mouse with elastin production being controlled by the human elastin gene in a bacterial artificial chromosome. The temporal and spatial expression pattern of the human transgene mirrors the endogenous murine gene, and the human gene accurately recapitulates the alternative-splicing pattern found in humans. Human elastin protein interacts with mouse elastin to form functional elastic fibers and when expressed in the elastin haploinsufficient background reverses the hypertension and cardiovascular changes associated with that phenotype. Elastin from the human transgene also rescues the perinatal lethality associated with the null phenotype. The results of this study confirm that reestablishing normal elastin levels is a logical objective for treating diseases of elastin insufficiency such as supravalvular aortic stenosis. This study also illustrates how differences in gene structure and alternative splicing present unique problems for modeling human diseases in mice.

Topics: Alternative Splicing; Animals; Aorta; Aortic Stenosis, Subvalvular; Chromosomes, Artificial, Bacterial; Cutis Laxa; Disease Models, Animal; DNA; Elastin; Female; Gene Expression Regulation; Humans; Mice; Mice, Inbred C57BL; Mice, Transgenic; Phenotype

Bronchopulmonary dysplasia (BPD) is a chronic lung disease that adversely affects long-term pulmonary function as well as neurodevelopmental outcomes of preterm infants. Elastolytic proteases have been implicated in the pathogenesis of BPD. Cathepsin S (cat S) is a cysteine protease with potent elastolytic activity. Increased levels and activity of cat S have been detected in a baboon model of BPD.. To investigate whether deficiency of cat S alters the course of hyperoxia-induced neonatal lung injury in mice.. Newborn wild-type and cat S-deficient mice were exposed to 80% oxygen for 14 days. Histologic and morphometric analysis were performed and bronchoalveolar lavage protein and cells were analyzed. Lung elastin was assessed by real-time polymerase chain reaction, in situ hybridization, desmosine analysis, and Hart's stain. Distribution of myofibroblasts was analyzed by immunofluorescence. Hydroxyproline content of lung tissues was measured.. Hyperoxia-exposed cat S-deficient mice were protected from growth restriction and had improved alveolarization, decreased septal wall thickness, lower number of macrophages, and lower protein concentration in bronchoalveolar lavage fluid. alpha-Smooth muscle actin-expressing myofibroblasts accounted for at least some of the increased interstitial cellularity in hyperoxia-exposed mouse lungs and were significantly less in cat S-deficient lungs. Lung hydroxyproline content was increased in hyperoxia-exposed wild-type, but not in cat S-deficient lungs. Desmosine content was significantly reduced in both genotypes with hyperoxia.. Cathepsin S deficiency improves alveolarization, and attenuates macrophage influx and fibroproliferative changes in hyperoxia-induced neonatal mouse lung injury.

Topics: Animals; Animals, Newborn; Bronchoalveolar Lavage Fluid; Bronchopulmonary Dysplasia; Cathepsins; Collagen; Desmosine; Disease Models, Animal; Elastin; Humans; Hydroxyproline; Hyperoxia; Infant, Newborn; Lung; Lung Injury; Macrophages, Alveolar; Mice; Proteins; Pulmonary Alveoli; RNA, Messenger

Because current therapy to treat abdominal aortic aneurysm (AAA), and particularly to manage small AAA, is limited to elective surgical repair, we explored less invasive molecular therapy by simultaneous inhibition of the transcription factors nuclear factor (NF)kappaB and ets using a decoy strategy. Both NFkappaB and ets were shown to be markedly activated in human AAA. In addition, NFkappaB- and ets-positive cells were increased in the aneurysm wall, and a part of the expression of NFkappaB and ets was detected in migrating macrophages. Thus, we used chimeric decoy oligodeoxynucleotides (ODNs) containing consensus sequences of both NFkappaB and ets binding sites to treat AAA. Inhibitory effects of chimeric decoy ODNs on matrix metalloproteinase-1 and -9 expression were confirmed by ex vivo experiments using a human aorta organ culture. To examine the regressive effect in a rabbit already-formed AAA model, transfection by wrapping a delivery sheet containing chimeric decoy ODNs around the aneurysm was performed 1 week after incubation with elastase. Importantly, treatment with chimeric decoy ODNs significantly decreased the size of AAA. Interestingly, significant preservation of elastic fibers was observed with chimeric decoy ODN treatment, accompanied by a reduction of matrix metalloproteinase-2 and -9 and induction of macrophage apoptosis. Regression of AAA was also associated with an increase in elastin and collagen type I and III synthesis in the aneurysm wall. Minimally invasive molecular therapy targeted to the inhibition of NFkappaB and ets is expected to be useful for AAA through the rebalance of matrix synthesis and degradation.

Topics: Animals; Aorta; Aortic Aneurysm, Abdominal; Apoptosis; Binding Sites; Collagen; Consensus Sequence; Disease Models, Animal; Elastin; Humans; Macrophages; Matrix Metalloproteinase 2; Matrix Metalloproteinase 9; Molecular Mimicry; NF-kappa B; Oligodeoxyribonucleotides; Proto-Oncogene Protein c-ets-1; Rabbits

Calcification of vascular elastin occurs in patients with arteriosclerosis, renal failure, diabetes, and vascular graft implants. We hypothesized that pathological elastin calcification is related to degenerative and osteogenic mechanisms. To test this hypothesis, the temporal expression of genes and proteins associated with elastin degradation and osteogenesis was examined in the rat subdermal calcification model by quantitative real-time reverse transcription-polymerase chain reaction and specific protein assays. Purified elastin implanted subdermally in juvenile rats exhibited progressive calcification in a time-dependent manner along with fibroblast and macrophage infiltration. Reverse transcription-polymerase chain reaction analysis showed that relative gene expression levels of matrix metalloproteinases (MMP-2 and MMP-9) and transforming growth factor-beta1 were increased in parallel with calcification. Gelatin zymography showed strong MMP activities at early time points, which were associated with high levels of soluble elastin peptides. Gene expression of core binding factor alpha-1, an osteoblast-specific transcription factor, increased in parallel with elastin calcification and attained approximately 9.5-fold higher expression at 21 days compared to 3 days after implantation. Similarly, mRNA levels of the bone markers osteopontin and alkaline phosphatase also increased progressively, but osteocalcin levels remained unchanged. We conclude that degenerative and osteogenic processes may be involved in elastin calcification.

Topics: Alkaline Phosphatase; Animals; Calcinosis; Core Binding Factor Alpha 1 Subunit; Disease Models, Animal; Elastin; Fibroblasts; Gene Expression Regulation; Heart; Macrophages; Male; Matrix Metalloproteinase 2; Matrix Metalloproteinase 9; Osteogenesis; Osteopontin; Rats; Rats, Sprague-Dawley; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Sialoglycoproteins; Swine; Transforming Growth Factor beta; Transforming Growth Factor beta1; Up-Regulation

Mice lacking macrophage elastase (matrix metalloproteinase-12, or MMP-12) were previously shown to be protected from the development of cigarette smoke-induced emphysema and from the accumulation of lung macrophages normally induced by chronic exposure to cigarette smoke. To determine the basis for macrophage accumulation in experimental emphysema, we now show that bronchoalveolar lavage fluid from WT smoke-exposed animals contained chemotactic activity for monocytes in vitro that was absent in lavage fluid from macrophage elastase-deficient mice. Fractionation of the bronchoalveolar lavage fluid demonstrated the presence of elastin fragments only in the fractions containing chemotactic activity. An mAb against elastin fragments eliminated both the in vitro chemotactic activity and cigarette smoke-induced monocyte recruitment to the lung in vivo. Porcine pancreatic elastase was used to recruit monocytes to the lung and to generate emphysema. Elastin fragment antagonism in this model abrogated both macrophage accumulation and airspace enlargement.

Topics: Animals; Bronchoalveolar Lavage Fluid; Chemotaxis, Leukocyte; Disease Models, Animal; Disease Progression; Elastin; Emphysema; Macrophages, Alveolar; Matrix Metalloproteinase 12; Metalloendopeptidases; Mice; Mice, Inbred C57BL; Mice, Knockout; Monocytes; Peptide Fragments; Pulmonary Alveoli; Smoking

Diabetes is an independent risk factor for the development of neointimal hyperplasia and subsequent vein graft failure after coronary or peripheral artery bypass grafting. We evaluate a new mouse model of surgical vein grafting to investigate the mechanisms of neointimal formation in the setting of type 2 diabetes.. Surgical vein grafts were created by inserting vein segments from age-matched C57BL/KsJ wild-type mice into the infra-renal aorta of lepr(db/db) diabetic and C57BL/KsJ wild-type mice. Mice were euthanized &4 weeks later, and vein grafts were analyzed using morphometric and immunohistochemical techniques. A significant increase in neointimal formation was noted in lepr(db/db) mice (139+/-64 versus 109+/-62 mm2; P=0.008) after 4 weeks. This difference was mainly secondary to an increase in collagen formation within the lesion in the vein grafts from lepr(db/db) mice (0.53+/-0.4 versus 0.44+/-0.05; P<0.001), whereas only slight increases (P=not significant) in alpha actin-stained smooth muscle cells were noted in the lepr(db/db) mice.. We established a new physiologically relevant model of surgical vein grafting in mice. In this report, type 2 diabetes was associated with significant increase in extracellular matrix deposition in addition to increased smooth muscle cell deposition. This new model may allow mechanistic studies of cellular and molecular pathways of increased neointimal formation in the setting of diabetes.

Topics: Actins; Animals; Aorta, Abdominal; Bioprosthesis; Blood Vessel Prosthesis; Blood Vessel Prosthesis Implantation; Collagen; Diabetes Mellitus, Type 2; Disease Models, Animal; Elastin; Extracellular Matrix; Hyperplasia; Male; Mice; Mice, Inbred C57BL; Mice, Mutant Strains; Muscle, Smooth, Vascular; Receptors, Cell Surface; Receptors, Leptin; Transplantation, Heterotopic; Tunica Intima; Vena Cava, Inferior

The primary cause of early death in untreated Marfan syndrome (MFS) patients is aortic dilatation and dissection.. We investigated whether ascending aortic samples from the fibrillin-1-underexpressing mgR mouse model for MFS or a recombinant fibrillin-1 fragment containing an elastin-binding protein (EBP) recognition sequence can act as chemotactic stimuli for macrophages. Both the aortic extracts from the mgR/mgR mice and the fibrillin-1 fragment significantly increased macrophage chemotaxis compared with extracts from wild-type mice or buffer controls. The chemotactic response was significantly diminished by pretreatment of macrophages with lactose or with the elastin-derived peptide VGVAPG and by pretreatment of samples with a monoclonal antibody directed against an EBP recognition sequence. Mutation of the EBP recognition sequence in the fibrillin-1 fragment also abolished the chemotactic response. These results indicate the involvement of EBP in mediating the effects. Additionally, investigation of macrophages in aortic specimens of MFS patients demonstrated macrophage infiltration in the tunica media.. Our findings demonstrate that aortic extracts from mgR/mgR mice can stimulate macrophage chemotaxis by interaction with EBP and show that a fibrillin-1 fragment possesses chemotactic stimulatory activity similar to that of elastin degradation peptides. They provide a plausible molecular mechanism for the inflammatory infiltrates observed in the mgR mouse model and suggest that inflammation may represent a component of the complex pathogenesis of MFS.

Topics: Animals; Aorta; Cattle; Chemotactic Factors; Chemotaxis; Disease Models, Animal; Elastin; Fibrillin-1; Fibrillins; Macrophages; Marfan Syndrome; Mice; Mice, Mutant Strains; Microfilament Proteins; Peptide Fragments; Recombinant Fusion Proteins; Tissue Extracts

Cardiovascular disease (CVD) is the leading cause of death in the United States, with 70% of CVD mortalities the result of sequelae of atherosclerosis. An urgent need for enhanced delineation of vulnerable plaques has catalyzed the development of novel atherosclerosis imaging strategies that use X-ray computed tomography, magnetic resonance and ultrasound modalities. As suggested by the pathophysiology of plaque development and progression to vulnerability, insight to the focal material, i.e., mechanical, properties of arterial walls and plaques may enhance atherosclerosis characterization. We present acoustic radiation force impulse (ARFI) ultrasound in application to mechanically characterizing a raised focal atherosclerotic plaque in an iliac artery extracted from a relevant pig model. ARFI results are correlated to matched immunohistochemistry, indicating elastin and collagen composition. In regions of degraded elastin, slower recovery rates from peak ARFI-induced displacements were observed. In regions of collagen deposition, lower ARFI-induced displacements were achieved. This work demonstrates ARFI for characterizing the material nature of an atherosclerotic plaque.

Topics: Animals; Atherosclerosis; Cardiovascular Diseases; Collagen; Disease Models, Animal; Elasticity; Elastin; Hyperlipoproteinemia Type II; Iliac Artery; Swine; Ultrasonography

Enlargement of the respiratory air spaces is associated with the breakdown and reorganization of the connective tissue fiber network during the development of pulmonary emphysema. In this study, a mouse (C57BL/6) model of emphysema was developed by direct instillation of 1.2 IU of porcine pancreatic elastase (PPE) and compared with control mice treated with saline. The PPE treatment caused 95% alveolar enlargement (P = 0.001) associated with a 29% lower elastance along the quasi-static pressure-volume curves (P < 0.001). Respiratory mechanics were measured at several positive end-expiratory pressures in the closed-chest condition. The dynamic tissue elastance was 19% lower (P < 0.001), hysteresivity was 9% higher (P < 0.05), and harmonic distortion, a measure of collagen-related dynamic nonlinearity, was 33% higher in the PPE-treated group (P < 0.001). Whole lung hydroxyproline content, which represents the total collagen content, was 48% higher (P < 0.01), and alpha-elastin content was 13% lower (P = 0.16) in the PPE-treated group. There was no significant difference in airway resistance (P = 0.7). The failure stress at which isolated parenchymal tissues break during stretching was 40% lower in the PPE-treated mice (P = 0.002). These findings suggest that, after elastolytic injury, abnormal collagen remodeling may play a significant role in all aspects of lung functional changes and mechanical forces, leading to progressive emphysema.

Topics: Animals; Collagen; Computer Simulation; Disease Models, Animal; Elastin; Emphysema; Forced Expiratory Volume; Humans; Lung; Male; Mice; Mice, Inbred C57BL; Models, Biological; Nonlinear Dynamics; Pancreatic Elastase; Respiratory Mechanics; Swine

This study tested the hypotheses that chronic allergic inflammation induces not only bronchial but also lung parenchyma remodeling, and that these histologic changes are associated with concurrent changes in respiratory mechanics. For this purpose, airway and lung parenchyma remodeling were evaluated by quantitative analysis of collagen and elastin, immunohistochemistry (smooth-muscle actin expression, eosinophil, and dendritic cell densities), and electron microscopy. In vivo (airway resistance, viscoelastic pressure, and static elastance) and in vitro (tissue elastance, resistance, and hysteresivity) respiratory mechanics were also analyzed. BALB/c mice were sensitized with ovalbumin and exposed to repeated ovalbumin challenges. A marked eosinophilic infiltration was seen in lung parenchyma and in large and distal airways. Neutrophils, lymphocytes, and dendritic cells also infiltrated the lungs. There was subepithelial fibrosis, myocyte hypertrophy and hyperplasia, elastic fiber fragmentation, and increased numbers of myofibroblasts in airways and lung parenchyma. Collagen fiber content was increased in the alveolar walls. The volume proportion of smooth muscle-specific actin was augmented in distal airways and alveolar duct walls. Airway resistance, viscoelastic pressure, static elastance, and tissue elastance and resistance were significantly increased. In conclusion, prolonged allergen exposure induced remodeling not only of the airway wall but also of the lung parenchyma, leading to in vivo and in vitro mechanical changes.

Topics: Actins; Airway Resistance; Animals; Asthma; Bronchi; Collagen; Disease Models, Animal; Elastin; Hyperplasia; Hypertrophy; In Vitro Techniques; Lung; Mice; Mice, Inbred BALB C; Microscopy, Electron; Muscle, Smooth; Pulmonary Alveoli; Pulmonary Eosinophilia; Pulmonary Fibrosis; Respiratory Hypersensitivity; Respiratory Mechanics

The production of the inflammatory cytokine interleukin (IL)-1 is increased in lungs of patients with chronic obstructive pulmonary disease (COPD) or asthma. To characterize the in vivo actions of IL-1 in the lung, transgenic mice were generated in which human IL-1beta was expressed in the lung epithelium with a doxycycline-inducible system controlled by the rat Clara cell secretory protein (CCSP) promoter. Induction of IL-1beta expression in the lungs of adult mice caused pulmonary inflammation characterized by neutrophil and macrophage infiltrates. IL-1beta caused distal airspace enlargement, consistent with emphysema. IL-1beta caused disruption of elastin fibers in alveolar septa and fibrosis in airway walls and in the pleura. IL-1beta increased the thickness of conducting airways, enhanced mucin production, and caused lymphocytic aggregates in the airways. Decreased immunostaining for the winged helix transcription factor FOXA2 was associated with goblet cell hyperplasia in IL-1beta-expressing mice. The production of the neutrophil attractant CXC chemokines KC (CXCL1) and MIP-2 (CXCL2), and of matrix metalloproteases MMP-9 and MMP-12, was increased by IL-1beta. Chronic production of IL-1beta in respiratory epithelial cells of adult mice causes lung inflammation, enlargement of distal airspaces, mucus metaplasia, and airway fibrosis in the adult mouse.

Topics: Animals; Asthma; Base Sequence; Bronchoalveolar Lavage Fluid; Chemokines, CXC; Collagen; Disease Models, Animal; DNA, Complementary; Elastin; Gene Expression; Humans; Inflammation; Interleukin-1; Lymphocytes; Matrix Metalloproteinases; Mice; Mice, Transgenic; Organ Size; Organ Specificity; Pulmonary Disease, Chronic Obstructive; Pulmonary Emphysema; Respiratory System; RNA, Messenger; Tumor Necrosis Factor-alpha

Diabetes is a risk factor for the development of cardiovascular diseases associated with impaired angiogenesis or increased endothelial cell apoptosis.. Here it is shown that angiogenic repair of ischemic hindlimbs was impaired in Lepr(db/db) mice, a leptin receptor-deficient model of diabetes, compared with wild-type (WT) C57BL/6 mice, as evaluated by laser Doppler flow and capillary density analyses. To identify molecular targets associated with this disease process, hindlimb cDNA expression profiles were created from adductor muscle of Lepr(db/db) and WT mice before and after hindlimb ischemia using Affymetrix GeneChip Mouse Expression Set microarrays. The expression patterns of numerous angiogenesis-related proteins were altered in Lepr(db/db) versus WT mice after ischemic injury. These transcripts included neuropilin-1, vascular endothelial growth factor-A, placental growth factor, elastin, and matrix metalloproteinases implicated in blood vessel growth and maintenance of vessel wall integrity.. These data illustrate that impaired ischemia-induced neovascularization in type 2 diabetes is associated with the dysregulation of a complex angiogenesis-regulatory network.

Topics: Animals; Diabetes Mellitus, Type 2; Diabetic Angiopathies; Disease Models, Animal; Elastin; Gene Expression Profiling; Hindlimb; Ischemia; Leptin; Mice; Mice, Inbred C57BL; Mice, Mutant Strains; Microcirculation; Muscle, Skeletal; Neovascularization, Physiologic; Neuropilin-1; Oligonucleotide Array Sequence Analysis; Reverse Transcriptase Polymerase Chain Reaction; Transcription, Genetic

It has been suggested that aortic valve sclerosis (AVS) is an atherosclerotic disease process that can proceed to aortic stenosis. The absence of reports studying an animal model of the early stages of this disease has precluded the development of preventive therapeutic strategies. A cholesterol-fed (0.25% cholesterol in chow) rabbit model of atherosclerosis that is characterized by a moderate level of hypercholesterolemia was studied to determine its efficacy as a model of early AVS. Cellular, structural and morphological changes in the aortic valves of these rabbits were studied.. Twenty rabbits were assigned randomly to four experimental groups: Group 1 received normal chow for 40 weeks; group 2 received 0.25% cholesterol-supplemented chow for 20 weeks; group 3 received 0.25% cholesterol-supplemented chow for 40 weeks; and group 4 received 0.25% cholesterol-supplemented chow for 20 weeks followed by normal chow for an additional 20 weeks. The aortas and aortic valves were analyzed using immunohistochemical and histological methods to detect cellular and structural components of the developing lesions.. All rabbits in groups 2, 3 and 4 developed atherosclerotic lesions in their aortas. Aortic valves from these animals demonstrated thickening, lipid deposition, a change in collagen content and organization, a reorganization of elastin, and the presence of both macrophage infiltrate and osteopontin.. These findings were consistent with the suggestion of a link between atherosclerosis and AVS. Results were also similar to changes reported in human sclerotic aortic valves, suggesting the suitability of this rabbit model of atherosclerosis as a model for AVS.

Topics: Animals; Aorta; Aortic Valve; Arteriosclerosis; Cholesterol, Dietary; Collagen; Diet, Atherogenic; Disease Models, Animal; Elastin; Humans; Hypercholesterolemia; Immunohistochemistry; Lipids; Macrophages; Male; Osteopontin; Phosphoproteins; Rabbits; Random Allocation; Sclerosis; Sialoglycoproteins

A general formula (Oka and Azuma's equation) has been rigorously derived for the circumferential wall tension in a hollow cylindrical tube in equilibrium. To evaluate the validity and usefulness of Oka and Azuma's equation, T = P(1) x r(1) - P(2) x r(2) (T, circumferential wall tension; P(1) and P(2), internal and external pressures of the tube; r(1) and r(2), the corresponding internal and external radii), we experimentally investigated changes in circumferential wall tension of noninjured (control) and injured dog common carotid arteries by using a newly developed apparatus with a photo- and X-ray-sensitive image sensor. We also studied histological features of the control and injured arteries with special reference to the relation of biomechanical properties. Two types of animal models with injured arteries--balloon-induced neointima or external collar-induced intimal thickening--were adopted in the present study. In the control arteries, the circumferential wall tension was experimentally confirmed to change from negative to positive by an increase in intraluminal pressure ranging from 50 to 180 mmHg. The critical intraluminal pressure that produced 0 dyne/cm of the circumferential wall tension was around 135 mmHg. The activation of arterial smooth muscles caused a significant increase in the critical pressure in the control arteries. In the arteries injured by neointima, the critical intraluminal pressure was significantly lower than that in the control. The activation of smooth muscles also significantly increased the critical pressure in the injured arteries. Histological examination demonstrated the existence of a circumferential neointimal formation along with a shortening of the internal diameter. In other arteries injured by intimal thickening, the circumferential wall tension was always negative at intraluminal pressure ranging from 50 to 180 mmHg. Newly developed structures consisted of elastic and collagen fibers, smooth muscles, and extracellular matrix in the intima and media of the injured arteries. These experimental findings suggest that the circumferential wall tension of dog common carotid arteries has been confirmed experimentally to become negative. We have also concluded that circumferential wall tension calculated with Oka-Azuma's equation may be one of the best parameters for evaluating changes in the biomechanical and histological properties of pathologically injured arteries.

Topics: Animals; Biomechanical Phenomena; Carotid Artery Injuries; Carotid Artery, Common; Catheterization; Collagen; Diagnostic Imaging; Disease Models, Animal; Dogs; Elastin; Female; Male; Mathematics; Muscle, Smooth, Vascular; Tunica Intima

The matrix-degrading activity of several proteases are involved in the accelerated breakdown of extracellular matrix associated with vascular remodeling during the development of atherosclerosis and vascular injury-induced neointimal formation. Previous studies have shown that the potent elastolytic cysteine proteases, cathepsins S and K, are overexpressed in atherosclerotic lesions in human and animal models. However, the role of these cathepsins in vascular remodeling remains unclear. In the present study, the expressions of cathepsin S and K and their inhibitor cystatin C were examined during arterial remodeling using a rat carotid artery balloon-injury model. The increase in both cathepsin S and K mRNA levels was observed from day 1 and day 3 through day 14 following the induction of balloon injury, respectively. Western blotting analysis revealed that both cathepsin S and K protein levels also increased in the carotid arteries during neointima formation, coinciding with an increase elastolytic activity assayed using Elastin-Congo red, whereas, no significant change in the expressions of cystatin C mRNA and protein was observed during follow-up periods after injury. Immunohistochemistry, Western blot, and in situ hybridization showed that the increase of cathepins S and K and the decrease of cystatin C occurred preferentially in the developing neointima. These findings suggest that cathepsin S and K may participate in the pathological arterial remodeling associated with restenosis.

Topics: Angioplasty, Balloon; Animals; Blotting, Western; Carotid Artery Injuries; Cathepsins; Cystatin C; Cystatins; Cysteine Endopeptidases; Disease Models, Animal; Elastin; Endothelium, Vascular; Enzyme Induction; Immunohistochemistry; In Situ Hybridization; Male; Polymerase Chain Reaction; Rats; Rats, Wistar

We have investigated the long-term effect of aluminum chloride (AlCl(3)) treatment on the calcification and inflammatory reaction of a porcine elastin-derived biomaterial (PEB) in a novel subdermal adult mouse model. Untreated PEB disks and PEB treated with AlCl(3) were implanted subdermally in BALB/c mice for 30, 60, and 180 days. The calcification of the elastin disks was examined with histological analysis and atomic absorption analysis of calcium content. The inflammatory reaction was evaluated both with histological analysis of explants and by an enzyme-linked immunosorbent assay of the serum in each mouse to determine the production of antielastin antibodies. Robust calcification was evident in all untreated PEBs with calcium levels of 107.1 +/- 11.8, 151.4 +/- 14.4, and 227.2 +/- 23.8 microg/mg for 30, 60, and 180 days, respectively. AlCl(3) treatment only temporarily prevented the calcification of the elastin disks for 30 days. By 60 and 180 days, the AlCl(3)-treated materials had significant calcification with 88.7 +/- 17.4 and 105.3 +/- 27.0 microg/mg calcium, respectively. The inflammatory reaction was moderate for both types of implants. The AlCl(3)-treated implants displayed significantly more macrophage and lymphocyte infiltration at 180 days after implantation, and a trend to higher humoral responses at 30 and 60 days when compared with untreated PEBs. We conclude that PEBs extensively calcify in the adult mice model. AlCl(3) treatment of elastin enhances the long-term immunological response to xenogenic elastin implants and merely delays the onset of calcification.

Topics: Aluminum Chloride; Aluminum Compounds; Amino Acids; Animals; Aorta; Biocompatible Materials; Calcinosis; Chlorides; Disease Models, Animal; Elastin; Female; Implants, Experimental; Mice; Mice, Inbred BALB C; Random Allocation; Skin; Swine

The purpose of the current study was to assess the histologic and rheologic properties of the scarred vocal fold lamina propria during a chronic phase of wound repair in a rabbit model. Eighteen rabbit larynges were scarred using a procedure that involved stripping the vocal fold lamina propria down to the thyroarytenoid muscle, using 3-mm microforceps. The approximate dimension of injury to the vocal fold was 3 x 1.5 x 0.5 mm [length x width x depth]. At 6 months postoperatively, histologic analysis of the scarred and control lamina propria in eight of these rabbits was completed for collagen, procollagen, elastin, and hyaluronic acid. Compared with control samples, scarred tissue samples revealed fragmented and disorganized elastin fibers. Additionally, collagen was significantly increased, organized, and formed thick bundles in the scarred vocal fold lamina propria. Measurements of the viscoelastic shear properties of the scarred and control lamina propria in the remaining 10 rabbits revealed increased elastic shear modulus (G') in 8 of 10 scarred samples and increased dynamic viscosity (eta') in 9 of 10 scarred samples. Although rheologic differences were not statistically significant, they revealed that on average, scarred samples were stiffer and more viscous than the normal controls. Histologic data are interpreted as indicating that by 6 months postinjury, the scarred rabbit vocal fold has reached a mature phase of wound repair, characterized by an increased, organized, and thick bundle collagen matrix. Rheologic data are interpreted as providing support for the potential role of increased, thick bundle collagen, and a disorganized elastin network on shear stiffness and dynamic viscosity in the chronic vocal fold scar. Based on these results, a 6-month postoperative time frame is proposed for future studies of chronic vocal fold scarring using the rabbit animal model.

Topics: Animals; Chronic Disease; Cicatrix; Collagen; Disease Models, Animal; Elastin; Hyaluronic Acid; Image Processing, Computer-Assisted; Immunohistochemistry; Male; Procollagen; Rabbits; Rheology; Viscosity; Vocal Cords; Wound Healing

Elevated plasma homocysteine has been associated with cardiovascular disease, although a causal relationship is unclear. The purpose of this study was to evaluate whether mild hyperhomocysteinemia (H-Hcy) may increase vascular stiffness of small arteries.. Wild-type (+/+) and heterozygous (+/-) methylenetetrahydrofolate reductase (Mthfr) knockout mice, a new model of mild H-Hcy, were treated with vehicle or angiotensin (Ang) II infusion (400 ng/kg per min s.c.). Second-order mesenteric arteries were studied on pressurized myograph. They were exposed to intraluminal pressures ranging from 3 to 140 mmHg. Media thickness and lumen diameter were measured at each pressure level to determine wall mechanical properties. Collagen type I/III and elastin deposition in the vascular wall were evaluated by confocal immunofluorescence microscopy.. Media-to-lumen ratio was similar in Mthfr and Mthfr mice, and significantly increased by Ang II. The stress-strain relationship was shifted to the left in small mesenteric arteries from Mthfr compared to Mthfr mice, indicating that mild H-Hcy is associated with stiffer vessels. Ang II treatment in Mthfr mice enhanced the leftward shift in the stress-strain relationship and significantly increased the elastic modulus, suggesting the presence of stiffer wall components in small arteries in these animals. Increased collagen type I/III accumulation and decreased elastin content in the media of mesenteric arteries was noted in Mthfr compared to Mthfr mice. Ang II infusion augmented vascular collagen deposition in both groups, more substantially in Mthfr mice.. Mild hyperhomocysteinemia is associated with stiffer small arteries with increased collagen deposition in the media. These changes are accentuated by Ang II-induced blood pressure elevation.

Topics: Angiotensin II; Animals; Blood Pressure; Collagen; Disease Models, Animal; Elastin; Female; Homocysteine; Hyperhomocysteinemia; Male; Mesenteric Arteries; Methylenetetrahydrofolate Reductase (NADPH2); Mice; Mice, Inbred BALB C; Mice, Knockout; Vasoconstrictor Agents

Babies with congenital diaphragmatic hernia (CDH) suffer from pulmonary hypoplasia and pulmonary hypertension. Elastin is a critical component of the extracellular matrix (EM) involved in pulmonary development and mechanics. Because CDH lungs are developmentally immature and have reduced compliance, the authors hypothesized that elastin deposition would be reduced and disorganized in the nitrofen rat model of CDH.. Time-dated pregnant Sprague-Dawley rats were fed 100 mg of nitrofen on day 9 of gestation. Control rats did not receive nitrofen. The authors analyzed three groups of rats (n = 10 for each group): (1) control (C), (2) nitrofen no CDH (NC), and (3) nitrofen-induced CDH (CDH). On day 21.5 (term, 22 days), the fetuses were delivered by cesarean section, and the fetal lung was harvested. Elastin content, mRNA expression, and distribution were assessed with desmosine analysis, Northern blot analysis, and Hart's staining, respectively.. The mean desmosine content in picomole desmosine per milligram protein (pmD/mgP) +/- SD was 30 +/- 6.8 (C, n = 10), 25.1 +/- 10.1 (NC, n = 10), and 21.6 +/- 6.4 (CDH, n = 10). The comparison between CDH and controls was statistically significant (P =.026). Northern blot analysis showed decreased mRNA expression in the CDH sample. Hart's staining showed developmentally immature CDH lungs with less elastin deposition and disorganized distribution.. Pulmonary elastin expression is decreased and disorganized in the nitrofen-induced rat model of CDH. The decreased expression appears to be regulated at the level of transcription. Altered mechanical forces may be responsible for mediating the expression of elastin in CDH.

Topics: Animals; Desmosine; Disease Models, Animal; Elastin; Female; Hernia, Diaphragmatic; Lung; Phenyl Ethers; Pregnancy; Rats; Rats, Sprague-Dawley; RNA, Messenger

This study examined the effects of amniocyte-based engineered tendons on partial diaphragmatic replacement.. Ovine mesenchymal amniocytes were labeled with green fluorescent protein (GFP), expanded, and seeded into a collagen hydrogel. Composite grafts (20 to 25 cm2) based on acellular dermis (group I), or acellular small intestinal submucosa (group II) received either a cell-seeded or an acellular hydrogel within their layers. Newborn lambs (n = 20) underwent partial diaphragmatic replacement with either an acellular or a cellular autologous construct from either group. At 3 to 12 months' postoperatively, implants were subjected to multiple analyses.. Diaphragmatic hernia recurrence was significantly higher in animals with acellular grafts (5 of 5) then in animals with cellular ones (1 of 4) in group I (P <.05) but not in group II (3 of 6 and 4 of 5, respectively). Cellular grafts had higher modular (5.27 +/- 1.98 v. 1.27 +/- 0.38 MPa) and ultimate (1.94 +/- 0.70 v. 0.29 +/- 0.05 MPa) tensile strength than acellular implants in group I (P <.05), but not in group II. Quantitative analyses showed no differences in extracellular matrix components between cellular and acellular implants in either group. All cellular implants showed GFP-positive cells.. Diaphragmatic repair with an autologous tendon engineered from mesenchymal amniocytes leads to improved mechanical and functional outcomes when compared with an equivalent acellular bioprosthetic repair, depending on scaffold composition. The amniotic fluid may be a preferred cell source for engineered diaphragmatic reconstruction.

Topics: Amniotic Fluid; Animals; Animals, Newborn; Cell Differentiation; Cells, Cultured; Collagen; Collagen Type I; Diaphragm; Disease Models, Animal; Elastin; Genes, Reporter; Glycosaminoglycans; Hernia, Diaphragmatic; Hernia, Diaphragmatic, Traumatic; Hernias, Diaphragmatic, Congenital; Hydrogels; Laparotomy; Mesenchymal Stem Cell Transplantation; Mesenchymal Stem Cells; Sheep; Tendons; Tensile Strength; Tissue Engineering; Transplantation, Autologous

Laser-assisted end-to-end vascular anastomosis of an elastin heterograft to native artery may avoid the problems associated with currently available vascular synthetic grafts and conventional suture anastomosis.. A total of 21 anastomoses in the carotid arteries of seven domestic pigs were performed with an 800-nm laser and an albumin stent plus solder. There were five artery to artery and 16 elastin heterograft to native artery anastomoses. Operative parameters, vascular patency, and histology of the anastomoses were evaluated.. Out of 21 anastomoses, 20 were patent at 3 h. The average amount of total energy used was 212 Joules in artery to artery anastomosis and 273 Joules in elastin heterograft to native artery. Histology shows coagulative necrosis of the adventitia, hypereosinophilic contraction band in the media in native artery, and no change in elastin heterografts.. Laser-assisted vascular anastomosis of elastin heterograft to medium size vessel is possible. Albumin stent played an important role in strength of the anastomosis. Chronic studies are warranted to determine long-term patency and histology of the laser-assisted vascular anastomosis.

Topics: Albumins; Anastomosis, Surgical; Animals; Carotid Arteries; Disease Models, Animal; Elastin; Female; Laser Therapy; Male; Sensitivity and Specificity; Stents; Sus scrofa; Transplantation, Heterologous; Tunica Media; Vascular Patency; Vascular Surgical Procedures

Isolated systolic hypertension is the predominant form of hypertension in the elderly population. Reduction of arterial compliance appears to contribute to the elevation of pulse pressure (PP) and among potential mechanisms, gradual vascular calcification, fragmentation of elastic lamellae, and augmentation of rigid component like collagen could contribute to increase aortic stiffening. Few experimental models of the disease are currently available.. To induce large artery calcification, rats were treated with warfarin and vitamin K(1) (WK) for 4 and 8 weeks, to inhibit the maturation of matrix Gla protein. The impact of chronic PP elevation was determined on large artery and cardiac remodeling and on aortic endothelial function.. The WK treatment led to aortic medial calcification and a proportional elevation of PP, attributable mainly to a selective elevation of systolic blood pressure. The chronic treatment also increased collagen, whereas elastin decreased in the aorta. Pulse wave velocity, an index of aortic stiffening, increased in rats treated with WK. However, indices of left ventricular and aortic hypertrophy and remodeling remained normal. In addition, the WK treatment did not modify the vasoconstriction to norepinephrine and endothelin-1, and the vasodilatory response to acetylcholine and sodium nitroprusside.. Chronic treatment with WK represents a new model of isolated systolic hypertension with several characteristics of the human disease. The relative ease to induce calcification in this model may help to foster more fundamental research, which is lacking in this type of hypertension.

Topics: Animals; Anticoagulants; Antifibrinolytic Agents; Aorta; Calcinosis; Calcium; Collagen; Disease Models, Animal; Drug Administration Schedule; Elastin; Hemodynamics; Hypertension; Male; Rats; Rats, Wistar; Renin; Systole; Vascular Diseases; Vasomotor System; Vitamin K 1; Warfarin

Calcification of bioprosthetic heart valves fabricated from glutaraldehyde (GA)-pretreated heterograft tissue is frequently responsible for the clinical failure of these devices. Stentless bioprostheses fabricated from GA-fixed porcine aortic valves pose an important challenge in this regard, as pathologic calcification can affect not only the bioprosthetic cusps, but also the aortic wall segment.. A synergistic approach was used to prevent bioprosthetic cusp and aortic wall calcification. Ethanol pretreatment of bioprosthetic heart valves was shown to inhibit cuspal calcification due to multiple mechanisms, including alterations of collagen structure and lipid extraction. AlCl3 pretreatment of bioprostheses to prevent calcification was also investigated; this alters elastin structure, inhibits alkaline phosphatase, and complexes with phosphoesters, thereby inhibiting aortic wall mineralization.. Experimental data from rat subdermal implants and sheep mitral replacements showed successful synergism with co-pretreatment of porcine aortic valve bioprostheses with ethanol and AlCl3. Significant inhibition of both cusp and aortic wall calcification was achieved by differential pretreatments that restrict AlCl3 to only the aortic wall, and not the cusp, accompanied by ethanol cuspal exposure. Sequential exposure of bioprostheses, first to AlCl3 and then to ethanol, led to unexpectedly severe cuspal calcification.. Differential pretreatment of stentless bioprostheses with ethanol and AlCl3 can effectively inhibit both cuspal and aortic wall calcification.

Topics: Aluminum; Animals; Aortic Valve; Bioprosthesis; Calcinosis; Coated Materials, Biocompatible; Collagen Type I; Disease Models, Animal; Dose-Response Relationship, Drug; Drug Synergism; Drug Therapy, Combination; Elastin; Ethanol; Heart Valve Diseases; Heart Valve Prosthesis; Lipid Metabolism; Magnetic Resonance Spectroscopy; Male; Models, Cardiovascular; Rats; Rats, Sprague-Dawley; Sheep; Solvents

Clinical evidence indicates that hemodynamic conditions influence abdominal aortic aneurysm (AAA) disease. We modified blood flow to evaluate the effects of wall shear stress (WSS) and relative wall strain (RWS) on aneurysm structure and cellularity.. Rodent AAAs were created with porcine pancreatic elastase infusion. In group 1 AAA WSS was increased with left femoral arteriovenous fistula creation, whereas in group 2 AAA WSS was decreased with left iliac artery ligation. Aortic flow, wall motion, and blood pressure were recorded in both groups. AAA diameter, endothelial and smooth muscle cellularity (CD31 and alpha-smooth muscle actin immunostaining), markers for cell proliferation (5-bromodeoxyuridine), endothelial and smooth muscle cell growth factor production (vascular endothelial growth factor-D and platelet-derived growth factor-beta, respectively), and apoptosis (deoxyuridine triphosphate nick end-labeled [TUNEL] stain) were compared between groups when the animals were killed.. Arteriovenous fistula creation increased WSS (high-flow AAA) by 300% and RWS by 150%. Iliac ligation reduced WSS (low-flow AAA) by 60%. Neither procedure significantly altered systolic, diastolic, or mean aortic pressure. When the animals were killed 7 days after elastase infusion, low-flow AAAs were significantly larger than high-flow AAAs. High-flow AAAs also contained more endothelial cells and smooth muscle cells, and evidence of increased growth factor production, cell proliferation, and decreased apoptosis. No difference in type or severity of AAA inflammatory cell infiltrate was noted between groups.. High flow conditions stimulate endothelial cell and smooth muscle cell proliferation in experimental aneurysms. Enhanced cellularity may stabilize aortic integrity, limiting aneurysm growth. Increased lower extremity activity may prevent or retard AAA disease through salutary effects on aortic remodeling mediated by endothelial cells and smooth muscle cells.

Topics: Animals; Aorta, Abdominal; Aortic Aneurysm, Abdominal; Blood Flow Velocity; Blood Pressure; Cell Differentiation; Collagen; Disease Models, Animal; Disease Progression; Elastin; Endothelial Growth Factors; Endothelium, Vascular; Models, Cardiovascular; Myocytes, Smooth Muscle; Rats; Rats, Inbred Strains; Receptors, Vascular Endothelial Growth Factor; Shear Strength; Vascular Endothelial Growth Factor D

To evaluate the effects doxycycline (Dox) in animal models of early abdominal aortic aneurysm.. Of 43 male Wistar rats, 33 underwent intraluminal perfusion of the abdominal aorta with thioglycolate plus plasmin to reproduce early aortic aneurysm. These rats then were treated for 7 days with subcutaneous injections of Dox or saline. The 10 remaining rats underwent intra-aortic perfusion with saline and were injected subcutaneously with saline. On day 7, the rats were killed after abdominal aortic diameters were measured. Some aortic specimens were examined microscopically after elastica van Gieson (EVG) and hematoxylin-eosin (H&E) staining. In other specimens, the matrix metalloproteinase (MMP) activity in tissue extracts was evaluated by gelatin zymography.. Among the thioglycolate plus plasmin-perfused rats, the degree of aortic dilation was less in Dox-treated than in saline-treated rats. EVG staining indicated that Dox maintained a nearly normal pattern of elastic lamellae and normal medial elastin thickness. The aortic inflammatory response was not suppressed by Dox in H&E staining. In gelatin zymography, Dox reduced the MMP-9 activity, but did not significantly change either MMP-2 or the percentage of activated MMP-2.. Dox inhibited experimental aneurysmal dilation by preserving medial elastin. This effect involved the suppression of MMP-9 but not of the MMP-2 activity.

Topics: Animals; Anti-Bacterial Agents; Aorta, Abdominal; Aortic Aneurysm, Abdominal; Disease Models, Animal; Doxycycline; Elastin; Male; Rats; Rats, Wistar

To establish the relationship between elastin degradation and aneurysm growth in New Zealand white rabbit model aneurysms, and to explore the potential for pharmacologic inhibition of elastinolysis and aneurysm growth with use of the matrix metalloproteinase (MMP) inhibitor doxycycline.. Elastase-induced, saccular aneurysms created in the right common carotid artery in 30 animals randomly divided into controls (n = 16) and doxycycline treated (n = 14) were studied. Aneurysm growth was determined by angiography and aneurysm specimens were collected at 7 and 14 days for histologic and immunohistochemical analysis.. Aneurysms were characterized by marked elastin degradation and thickening of the arterial wall media in the absence of inflammatory cell markers. There was no evidence for expression of MMPs in the aneurysm wall at any time point. Aneurysm formation and growth were not prevented by the systemic administration of doxycycline. Mean aneurysm width increased from 3.1 +/- 0.7 mm at 3 days to 3.7 +/- 0.8 mm at 7 days and 4.2 +/- 0.8 mm at 14 days (P =.012 and P =.017, respectively). There was no statistically significant difference in aneurysm size and elastin content at any time point between doxycycline treated and control animals.. Elastase-induced rabbit aneurysm formation is accompanied by total elastin destruction that was not inhibited by the administration of doxycycline. Aneurysms in this model may be caused by the initial infusion of elastase, rather than by ongoing degradation from endogenous proteases released by inflammatory cells.

Topics: Animals; Carotid Artery Diseases; Disease Models, Animal; Doxycycline; Elastin; Intracranial Aneurysm; Matrix Metalloproteinase Inhibitors; Pancreatic Elastase; Rabbits; Random Allocation

Topics: Animals; Body Weight; Collagen Type I; Collagen Type III; Disease Models, Animal; Elastin; Extracellular Matrix Proteins; Female; Fetal Diseases; Fibrillins; Fibronectins; Gene Expression; Hydronephrosis; Ligation; Male; Microfilament Proteins; Organ Size; Pregnancy; RNA, Messenger; Sex Factors; Sheep; Ultrasonography; Urinary Bladder; Urinary Bladder Neck Obstruction

The macular mouse is a mutant mouse with the same gene abnormality as that of Menkes' disease, and it exhibits symptoms and abnormalities similar to those of Menkes' disease. In an electron microscopic study, we examined morphological changes in the internal elastic lamina (IEL) of the elastic arteries (EA) and the muscular arteries (MA) in a patient with Menkes' disease and in the macular mouse, an animal model of this disease. The IEL of the EA was significantly thinner in the macular mouse than that in controls, but the IEL of the MA in the macular mouse was significantly thicker than that of the controls. These contrary results for the thickness of the IEL in the MA and the EA in this animal model of Menkes' disease may reflect differences in the anatomical and pathophysiological properties of the two types of vessels.

Topics: Animals; Blood Vessels; Child, Preschool; Disease Models, Animal; Elastic Tissue; Elastin; Female; Humans; Immunohistochemistry; Male; Menkes Kinky Hair Syndrome; Mice; Mice, Mutant Strains; Microscopy, Electron

Isolated systolic hypertension (ISH) is the predominant form of hypertension in the elderly population and drug treatment is unsatisfactory. We compared the efficacy of an endothelin-receptor antagonist (darusentan), an angiotensin-receptor blocker (irbesartan) and a thiazide diuretic (hydrochlorothiazide, HCTZ) to prevent and regress pulse pressure (PP) elevation and remodeling of large and small arteries, in a rat model of ISH obtained by the chronic administration of warfarin and vitamin K1 (WK).. Warfarin and vitamin K1 treatment for 4 or 8 weeks led to an elevation of PP, associated with increases in aortic calcium deposition and the ratio of collagen to elastin (C/E). Despite these changes in the composition of the aortic wall, the global structure of the aorta was unchanged. In contrast, an outward hypertrophic remodeling was observed in the middle cerebral artery. An early treatment with all drugs (darusentan, irbesartan, HCTZ) prevented PP elevation, changes of aortic media composition and the development of vascular remodeling. However, after 4 weeks of ISH, only darusentan and irbesartan reduced PP when administered from week 4 to 8. Darusentan was the most effective to regress existent aortic calcification, while only irbesartan reversed small artery hypertrophic remodeling.. During the development of ISH, drug treatment appears more beneficial when started early. Indeed, the three agents prevented PP elevation, aortic calcification and C/E increase in the aorta, and hypertrophy in small arteries. In contrast, once the disease is established, endothelin appears crucial in the maintenance of aortic calcification, while angiotensin II sustains small artery hypertrophy.

Topics: Animals; Antihypertensive Agents; Aorta, Thoracic; Arteries; Biphenyl Compounds; Calcinosis; Collagen; Disease Models, Animal; Elastin; Hydrochlorothiazide; Hypertension; Irbesartan; Male; Middle Cerebral Artery; Phenylpropionates; Pyrimidines; Rats; Rats, Wistar; Tetrazoles

The Dahl sodium-sensitive hypertensive rat exhibits atherogenic lesions after the initiation of a high-sodium/high-fat diet. This study was designed to gauge the effect of a preadolescent high-fat diet on the postadolescent rate of atherogenesis after supplementation of the diet with sodium.. Fifty-three Dahl S male rats were assigned to 2 dietary groups for the postweaning to early adolescence period (3 to 12 weeks): 29 to a standard diet (low-fat/low-sodium) and 24 to a high-fat/low-sodium diet. At age 9 weeks (just after puberty), animals from the high-fat group exhibited a relatively diminished density of coronary elastic fibers. There was no evidence of either lipid or monocytic infiltration of the subendothelial space. At age 12 weeks, most or all of the remaining animals in both groups were switched to a high-sodium/high-fat diet and were sampled through the following 8 weeks for the appearance of arterial lipid. After the switch, the high-fat-conditioned animals developed more extensive atherosclerotic pathological lesions more rapidly than their prepubertal standard-diet counterparts. The importance of the animal's stage of maturation in this effect was underscored by the observation that delaying onset of the high-fat diet to early adolescence resulted in no ultimate difference from the pubertal controls in elastic fiber density.. The maturation-dependent high-fat conditioning of these postweanling rats correlated with an accelerated rate of atherogenesis on the initiation of the high-sodium/high-fat diet, possibly as a direct result of an alteration in arterial elasticity.

Topics: Aging; Animals; Coronary Artery Disease; Coronary Vessels; Diet, Atherogenic; Diet, Sodium-Restricted; Dietary Fats; Disease Models, Animal; Disease Progression; Elastic Tissue; Elastin; Lipids; Male; Rats; Rats, Inbred Dahl; Sexual Maturation; Sodium, Dietary

We examined effects of hyperhomocysteinemia on structure and mechanics of cerebral arterioles. We measured plasma total homocysteine (tHcy) and pressure, diameter, and cross-sectional area of the vessel wall in maximally dilated cerebral arterioles in heterozygous cystathionine beta-synthase-deficient (CBS(+/-)) mice and wild-type (CBS(+/+)) littermates that were provided with drinking water that was unsupplemented (control diet) or supplemented with 0.5% L-methionine (high-methionine diet). Plasma tHcy was 5.0+/-1.1 micro mol/L in CBS(+/+) mice and 8.3+/-0.9 micro mol/L in CBS(+/-) mice (P<0.05 versus CBS(+/+) mice) fed the control diet. Plasma tHcy was 17.2+/-4.6 micro mol/L in CBS(+/+) mice and 21.2+/-3.9 micro mol/L in CBS(+/-) mice (P<0.05) fed the high-methionine diet. Cross-sectional area of the vessel wall was significantly increased in CBS(+/-) (437+/-22 micro m(2)) mice fed control diet and CBS(+/+) (442+/-36 micro m(2)) and CBS(+/-) (471+/-46 micro m(2)) mice fed high-methionine diet relative to CBS(+/+) (324+/-18 micro m(2)) mice fed control diet (P<0.05). During maximal dilatation, the stress-strain curves in cerebral arterioles of CBS(+/-) mice on control diet and CBS(+/+) and CBS(+/-) mice on high-methionine diet were shifted to the right of the curve in cerebral arterioles of CBS(+/+) mice on control diet, an indication that distensibility of cerebral arterioles was increased in mice with elevated levels of plasma tHcy. Thus, hyperhomocysteinemia in mice was associated with hypertrophy and an increase in distensibility of cerebral arterioles. These findings suggest that hyperhomocysteinemia promotes cerebral vascular hypertrophy and altered cerebral vascular mechanics, both of which may contribute to the increased incidence of stroke associated with hyperhomocysteinemia.

Topics: Animals; Arterioles; Basement Membrane; Blood Pressure; Brain; Collagen; Cystathionine beta-Synthase; Diet; Disease Models, Animal; Elastin; Genotype; Heterozygote; Hyperhomocysteinemia; Hypertrophy; Methionine; Mice; Mice, Inbred C57BL; Mice, Mutant Strains; Vascular Patency

Previous studies have demonstrated the development of cardiac fibrosis in aldosterone (Aldo)-salt hypertensive rats. Our aim was to determine the effects of Aldo and the Aldo receptor antagonist eplerenone (Epl) on in vivo mechanical properties of the carotid artery using echo-tracking system.. Aldo was administered (1 microg/h) in uninephrectomized Sprague-Dawley rats (SD) receiving a high-salt diet from 8 to 12 weeks of age. Uninephrectomized control SD rats received a normal salt diet without Aldo. Three groups of Aldo-salt rats were treated with 1, 10, or 30 mg/kg(-1) x d(-1) of Epl by gavage. Elasticity was measured by elastic modulus (Einc)-wall stress curves using medial cross-sectional area (MCSA). The structure of the arterial wall was analyzed by histomorphometry (elastin and collagen), immunohistochemistry (EIIIA fibronectin, Fn), and Northern blot (collagens I and III). Aldo produced increased systolic arterial pressure, pulse pressure, Einc, MCSA, and EIIIA Fn with no change in wall stress or elastin and collagen densities compared with controls without Aldo. No differences in collagen mRNA levels were detected between groups. Epl blunted the increase in pulse pressure in Aldo rats and normalized Einc-wall stress curves, MCSA, and EIIIA Fn. These effects were dose dependent and not accompanied by a reduction in wall stress.. Aldo is able to increase arterial stiffness associated with Fn accumulation, independently of wall stress. The preventive effects of Epl suggest a direct role for mineralocorticoid receptors in mechanical and structural alterations of large vessels in rat hyperaldosteronism.

Topics: Aldosterone; Animals; Blood Pressure; Blotting, Northern; Carotid Arteries; Collagen; Collagen Type I; Collagen Type III; Disease Models, Animal; Dose-Response Relationship, Drug; Elasticity; Elastin; Eplerenone; Fibronectins; Hyperaldosteronism; Immunohistochemistry; Injections, Subcutaneous; Male; Mineralocorticoid Receptor Antagonists; Nephrectomy; Rats; Rats, Sprague-Dawley; RNA, Messenger; Sodium, Dietary; Spironolactone; Ultrasonography; Vascular Patency

The form and function of the heart are the final result of an integration of cells, tissues, and extracellular material. The extracellular matrix (ECM) is a complex array of different molecular components, and it plays an important role for the transfer of mechanical force in both contraction and relaxation phases in the cardiac cycle. ECM plays also a significant role in the development of the heart. The aim of this study was to evaluate the expression of important ECM components in the heart of rats with induced CDH to test the hypothesis that an alteration of ECM may contribute to the cardiac maldevelopment, which recently has been identified as a contributive factor for the high mortality rate in babies with congenital diaphragmatic hernia (CDH).. CDH model was induced in pregnant rats after administration of 100 mg of nitrofen on day 9.5 of gestation (term, 22 days). In control animals the same dose of olive oil was given without nitrofen. Cesarean section was performed on day 21 of gestation. The fetuses were divided into 2 groups: normal control (n = 10) and nitrofen-induced CDH (n = 10). Reverse transcription polymerase chain reaction (RT-PCR) was performed to evaluate the relative amount of tropoelastin and alpha1 (I) procollagen mRNA expression. Elastin protein content was measured using enzyme-linked immunosorbent assay (ELISA).. There was a reduction in tropoelastin mRNA (P <.05) and procollagen mRNA (P <.05) in CDH compared with controls. The cardiac alpha-elastin content also was reduced in CDH (P <.01).. The reduced cardiac tropoelastin and procollagen gene expression and the reduced alpha-elastin content indicate that the heart in CDH structurally is immature. The reduced production of cardiac ECM may contribute to a contractile dysfunction, which makes the heart unable to respond to the hemodynamic load accompanying persistent pulmonary hypertension (PPH).

Topics: Abnormalities, Multiple; Actins; Animals; Disease Models, Animal; Elastin; Enzyme-Linked Immunosorbent Assay; Fetal Organ Maturity; Heart; Heart Defects, Congenital; Hernia, Diaphragmatic; Hernias, Diaphragmatic, Congenital; Phenyl Ethers; Procollagen; Rats; Rats, Sprague-Dawley; Reverse Transcriptase Polymerase Chain Reaction; Tropoelastin

Intimal hyperplasia is one of the main responses of the vascular wall to injury. In the current study, we tested the hypothesis that endoluminal seeding of host syngeneic vascular cells could limit intimal hyperplasia induced by either mechanical deendothelialization or chronic allograft rejection in rat aorta.. An experimental model of in situ seeding of syngeneic endothelial cells, smooth muscle cells (SMCs), and fibroblasts (FIBs) was used in mechanically deendothelialized and allografted aortas. In a preliminary study, the ability of the three cell types (n = 5 per group) to seed on the deendothelialized luminal surface of the aortic wall was evaluated after 2 days, with the use of fluorescent PKH as marker. In the first model, the abdominal aorta of Lewis rats was deendothelialized (n = 6) or deendothelialized and seeded with either SMCs (n = 6) or FIBs (n = 6) before flow was restored. In the allograft model, aortas were harvested from dark agouti rats and orthotopically grafted in Lewis receivers, directly (n = 6) or after deendothelialization. Deendothelialization was performed alone (n = 6) or associated with the seeding of similar host (Lewis) syngeneic SMCs (n = 6) or FIBs (n = 6). Results were evaluated at 2 months with histologic and morphometric methods.. SMCs and FIBs were able to adhere in situ to the deendothelialized aortic wall, whereas endothelial cells were not. In mechanically deendothelialized aortas, the seeding of syngeneic SMCs led to a significant reduction in intimal thickness compared with deendothelialized aortas or FIB-seeded aortas (26.9 +/- 1.7 microm vs 55.5 +/- 1.7 and 56.7 +/- 1.7 microm, respectively), and a lower nuclear content (382.2 +/- 35.7 microm(2) vs 779.6 +/- 65.9 and 529.6 +/- 24.3 microm(2), respectively) of neointima. After SMC seeding, intimal hyperplasia was richer in elastin, whereas after FIB seeding it was richer in collagen. In allografts, the seeding of syngeneic SMC led to a significant reduction in intimal thickness compared with control aortas, deendothelialized aortas, or FIB-seeded aortas (31.6 +/- 1.1 microm vs 88.55 +/- 2.8, 74.6 +/- 2.9, and 85.7 +/- 2.6 microm, respectively), and a reduced nuclear content of the neointima (444.9 +/- 23.4 microm(2) vs 1529.1 +/- 116, 972.3 +/- 50, and 645.2 +/- 32.4 microm(2), respectively). Differences observed in the extracellular matrix composition were equivalent to those observed in the mechanically deendothelialized model.. Our results suggest that endoluminal seeding of syngeneic SMCs can be effective in reducing intimal hyperplasia both in a deendothelialization model and in arterial allografts. SMC and FIB endoluminal seeding led to a significatively different accumulation of extracellular matrix in the intima.

Topics: Analysis of Variance; Animals; Aorta, Abdominal; Cell Adhesion; Cell Division; Cell Movement; Chronic Disease; Collagen; Disease Models, Animal; Elastin; Fibroblasts; Graft Rejection; Hyperplasia; Inflammation; Male; Muscle, Smooth, Vascular; Rats; Rats, Inbred Lew; Rats, Inbred Strains; Time Factors; Transplantation, Homologous; Transplantation, Isogeneic; Tunica Intima; Wound Healing

Emphysema causes a permanent destruction of alveolar walls leading to airspace enlargement, loss of elastic recoil, decrease in surface area for gas exchange, lung hyperexpansion, and increased work of breathing. The most accepted hypothesis of how emphysema develops is based on an imbalance of protease and antiprotease activity leading to the degradation of elastin within the fiber network of the extracellular matrix. Here we report novel roles for mechanical forces and collagen during the remodeling of lung tissue in a rat model of elastase-induced emphysema. We have developed a technique to measure the stress-strain properties of tissue sections while simultaneously visualizing the deformation of the immunofluorescently labeled elastin-collagen network. We found that in the elastase treated tissue significant remodeling leads to thickened elastin and collagen fibers and during stretching, the newly deposited elastin and collagen fibers undergo substantially larger distortions than in normal tissue. We also found that the threshold for mechanical failure of collagen, which provides mechanical stability to the normal lung, is reduced. Our results indicate that mechanical forces during breathing are capable of causing failure of the remodeled extracellular matrix at loci of stress concentrations and so contribute to the progression of emphysema.

Topics: Analysis of Variance; Animals; Biomechanical Phenomena; Bone Remodeling; Collagen; Disease Models, Animal; Disease Progression; Elastin; Emphysema; Functional Residual Capacity; Immunohistochemistry; Linear Models; Male; Pancreatic Elastase; Pulmonary Gas Exchange; Rats; Rats, Sprague-Dawley; Respiratory Mechanics; Stress, Mechanical; Work of Breathing

In a mouse model, we investigated whether different exposure protocol of ultraviolet-B with the same total doses could induce a different degree of photodamage in mouse skin. Two different exposure frequencies, three times or six times a week, were applied under the condition of weekly same cumulative irradiation dose equally for 10 weeks. Then the photodamage parameters such as skin wrinkling, histochemical dermal change and epidermal and dermal thickness were evaluated. Wrinkle grade, histological assessment by score, and dermal thickness did not reveal any difference between the two groups. However, at irradiation week 10 epidermal thickness of the three times a week irradiation group was significantly thicker than that of the six times a week irradiation group. The same cumulative dose resulted in different epidermal thickness. Our results suggested that exposure frequency or scheduling could influence the epidermal damage by ultraviolet radiation even though the cumulative dose is equal.

Topics: Animals; Biopsy; Collagen; Coloring Agents; Dermis; Disease Models, Animal; Elastic Tissue; Elastin; Environmental Exposure; Epidermis; Female; Glycosaminoglycans; Histocytochemistry; Image Processing, Computer-Assisted; Mice; Mice, Hairless; Radiation Dosage; Skin; Skin Aging; Ultraviolet Rays

Fluorescence emission analysis (FEA) has proven to be very sensitive for the detection of elastin, collagen and lipids, which are recognized as the major sources of autofluorescence in vascular tissues. FEA has also been reported to detect venous thromboemboli. In this paper we have tested the hypothesis that FEA can reproducibly detect in vivo and in vitro triggered plaque disruption and thrombosis in a rabbit model. Fluorescence emission (FE) spectra, recorded in vivo, detected Russell's viper venom (RVV)-induced transformation of atherosclerotic plaque. FE intensity at 410-490 nm 4 weeks after angioplasty was significantly lower (P < 0.0033 by analysis of variance) in RVV-treated rabbits when compared to control animals with stable plaque. FE spectral profile analyses also demonstrated a significant change in curve shape as demonstrated by polynomial regression analysis (R2 from 0.980 to 0.997). We have also demonstrated an excellent correlation between changes in FE intensity and the structural characteristics detected at different stages of "unstable atherosclerotic plaque" development using multiple regression analysis (R2 = 0.989). Thus, FEA applied in vivo is a sensitive and highly informative diagnostic technique for detection of triggered atherosclerotic plaque disruption and related structural changes, associated with plaque transformation, in a rabbit model.

Topics: Angioplasty, Balloon; Animals; Arteriosclerosis; Collagen; Daboia; Disease Models, Animal; Elastin; Fluorescence; Rabbits; Spectrometry, Fluorescence; Thrombosis; Viper Venoms

Previous findings vary regarding the timing and cause of elastin fiber degeneration in the elastase-induced rat abdominal aortic aneurysm model. We examined the timing and cause of elastin fiber degeneration after elastase infusion using two different elastase infusion times. Twenty-four Sprague-Dawley rats were divided into two groups. The infrarenal abdominal aorta was infused with 15 U of elastase for 15 min (n = 12, 15-min infusion group) or 30 min (n = 12, 30-min infusion group). In each group, three rats were killed immediately and 1, 3, and 7 days after infusion, and then the aortas were excised for a histologic examination. Elastin fibers did not stain, even immediately after elastase infusion, in the 30-min infusion group. The degeneration of elastin fibers did not progress in the 15-min infusion group during the period of observation. Inflammatory cells infiltrated mainly to the adventitia near regions where the degeneration of elastin fibers spread totally through the aortic media. Elastin fibers degenerate immediately after elastase infusion and thus seem to degenerate not due to endogenous proteinases that are produced by the infiltrating cells, but due to the exogenously infused elastase itself. Inflammatory cell infiltration was thus found to be a result of the degeneration of elastin fibers in this model.

Topics: Animals; Aortic Aneurysm, Abdominal; Disease Models, Animal; Elastin; Pancreatic Elastase; Rats; Rats, Sprague-Dawley

Elastin, a major extracellular matrix protein present in arterial walls provides elastic recoil and resilience to arteries. Elastin is prone to calcification in a number of cardiovascular diseases including atherosclerosis and bioprosthetic heart valve mineralization. We have recently shown that purified elastin when implanted subdermally in rats undergoes severe calcification. In the present study, we used this elastin implant model to investigate the molecular mechanisms underlying elastin calcification. Intense matrix metalloproteinase (MMP-2) and tenascin-C (TN-C) expression were seen in the proximity of the initial cal-cific deposits at 7 days. Gelatin zymography studies showed both MMP-2 (latent and active form) and MMP-9 expression within the implants. To investigate the role of MMPs in calcification, rats were administered a MMP inhibitor, (2S:-allyl-N:-hydroxy-3R:-isobutyl-N:-(1S:-methylcarbamoyl-2-ph enylet hyl)-succinamide (BB-1101) by daily injection, either systemically or at the implant site. The site-specific BB-1101 administration almost completely suppressed TN-C expression, as shown by immunohistochemical staining, within the implants. The systemic BB-1101 injections also significantly reduced TN-C expression within the elastin implants. Moreover, calcification of elastin implants was significantly reduced in the site-specific administration group (5.43 +/- 1.03 microg/mg Ca for BB-1101 group versus 21.71 +/- 1.19 for control group, P: < 0.001). Alizarin Red staining clearly showed that the elastin fibers were heavily calcified in the control group, whereas in BB-1101 group the calcification was scarce with few fibers showing initial calcification deposits. The systemic administration of BB-1101 also significantly reduced elastin calcification (28.07 +/- 5.81 control versus 16.92 +/- 2.56 in the BB-1101 group, P: < 0.05), although less than the site-specific administration. Thus, the present studies indicate that MMPs and TN-C play a role in elastin-oriented calcification.

Topics: Alkaline Phosphatase; Animals; Benzyl Compounds; Calcinosis; Dexamethasone; Disease Models, Animal; Drug Combinations; Elastin; Enzyme Inhibitors; Immunoenzyme Techniques; Implants, Experimental; Male; Matrix Metalloproteinase 2; Matrix Metalloproteinase 9; Matrix Metalloproteinase Inhibitors; Pentoxifylline; Protease Inhibitors; Rats; Rats, Sprague-Dawley; Succinates; Tenascin

Leukocyte infiltration and serine elastase activity lead to smooth muscle cell proliferation in association with posttransplant coronary arteriopathy and may also be involved in vein graft neointimal formation. A number of therapies have targeted cellular proliferation, but the inhibition of serine elastase-mediated extracellular matrix remodeling has not been investigated as a potential strategy to prevent neointimal formation and subsequent atherosclerotic degeneration in vein grafts.. We studied jugular vein grafts 48 hours after interposition into the carotid arteries of rabbits and demonstrated inflammatory cell infiltration and elevated serine elastase activity, a stimulus for matrix remodeling and deposition of elastin. Therefore, elastolytic activity in vein grafts was targeted through transient expression of the selective serine elastase inhibitor elafin with hemagglutinating virus of Japan liposome-mediated gene transfer. Elafin transfection reduced inflammation by 60% at 48 hours and neointimal formation by approximately 50% at 4 weeks after implantation. At 3 months, a 74% decrease in neointimal elastin deposition correlated with protection against cholesterol-induced macrophage infiltration and lipid accumulation, which were both reduced by approximately 50% in elafin-transfected grafts relative to controls.. Gene transfer of the selective serine elastase inhibitor elafin in vein grafts is effective in reducing the early inflammatory response. Although transient expression of elafin delays neointimal formation, it is also sufficient to cause an alteration in elastin content of the extracellular matrix, making it relatively resistant to atherosclerotic degeneration.

Topics: Animals; Arteriosclerosis; Carotid Arteries; Disease Models, Animal; Elastin; Extracellular Matrix; Gene Transfer Techniques; Graft Occlusion, Vascular; Immunohistochemistry; Jugular Veins; Liposomes; Proteinase Inhibitory Proteins, Secretory; Proteins; Rabbits; Respirovirus; Serine Proteinase Inhibitors; Transfection; Tunica Intima

Topics: Animals; Disease Models, Animal; Elastin; Emphysema; Humans; Interleukin-13; Matrix Metalloproteinase Inhibitors; Matrix Metalloproteinases; Mice; Mice, Transgenic

Extracellular matrix, particularly type I fibrillar collagen, provides tensile strength that allows cardiac muscle to perform systolic and diastolic functions. Collagen is induced during the transition from compensatory hypertrophy to heart failure. We hypothesized that cardiac stiffness during decompensatory hypertrophy is partly due to a decreased elastin:collagen ratio.. We prepared left ventricular tissue homogenates from spontaneously hypertensive rats (SHR) aged 30-36 weeks, which had compensatory hypertrophy with no heart failure, and from SHR aged 70-92 weeks, which had decompensatory hypertrophy with heart failure. Age- and sex-matched Wistar-Kyoto (WKY) rats were used as normotensive controls. In both SHR groups, increased levels of collagen were detected by immuno-blot analysis using type I collagen antibody. Elastin and collagen were quantitated by measuring desmosine/isodesmosine and hydroxyproline spectrophometrically, respectively. To determine whether the decrease in elastin content was due to increased elastinolytic activity of matrix metalloproteinase-2, we performed gelatin and elastin zymography on left ventricular tissue homogenates from control rats, SHR with compensatory hypertrophy and SHR with heart failure.. The elastin:collagen ratio was 0.242 +/- 0.008 in hearts from WKY rats. In SHR without heart failure, the ratio was decreased to 0.073 +/- 0.003 and in decompensatory hypertrophy with heart failure, the ratio decreased to 0.012 +/- 0.005. Matrix metalloproteinase-2 activity was increased significantly in SHR with heart failure compared with controls (P < 0.001). The level of tissue inhibitor of metalloproteinase-4 was increased in compensatory hypertrophy and markedly reduced in heart failure. Decorin was strongly reduced in decompensatory heart failure compared with control hearts.. Since collagen was induced in SHR with heart failure, decorin and elastin were decreased and the ratios of gelatinase A and elastase to tissue inhibitor of metalloproteinase-4 were increased, we conclude that heart failure is associated with adverse extracellular matrix remodeling.

Topics: Animals; Blotting, Western; Collagen; Decorin; Disease Models, Animal; Disease Progression; Elastin; Extracellular Matrix; Extracellular Matrix Proteins; Follow-Up Studies; Gelatinases; Heart Failure; Heart Ventricles; Hypertrophy, Left Ventricular; Matrix Metalloproteinase 2; Metalloendopeptidases; Myocardial Contraction; Proteoglycans; Rats; Rats, Inbred SHR; Rats, Inbred WKY; Spectrophotometry; Tensile Strength; Tissue Inhibitor of Metalloproteinases; Transforming Growth Factor beta

Abdominal aortic aneurysms (AAAs) are associated with chronic inflammation, disruption of medial elastin, and increased local production of elastolytic matrix metalloproteinases (MMPs). The purpose of this study was to investigate how treatment with a hydroxamate-based MMP antagonist (RS 132908) might affect the development of experimental AAAs.. Male Wistar rats underwent intraluminal perfusion of the abdominal aorta with 50 units of porcine pancreatic elastase followed by treatment for 14 days with RS 132908 (100 mg/kg/day subcutaneously; n = 8) or with vehicle alone (n = 6). The external aortic diameter (AD) was measured in millimeters before elastase perfusion and at death, with AAA defined as an increase in AD (DeltaAD) of at least 100%. Aortic wall elastin and collagen concentrations were measured with assays for desmosine and hydroxyproline, and fixed aortic tissues were examined by light microscopy.. AAAs developed in all vehicle-treated rats, with a mean AD (+/- SE) that increased from 1.60 +/- 0.03 mm before perfusion to 5.98 +/- 1.02 mm on day 14 (DeltaAD = 276.4 +/- 67.7%). AAAs developed in only five of eight animals (62.5%) after MMP inhibition, with a mean AD that increased from 1.56 +/- 0.05 mm to 3.59 +/- 0.34 mm (DeltaAD = 128.1 +/- 18.7%; P <.05, vs vehicle). The overall inhibition of aortic dilatation attributable to RS 132908 was 53.6 +/- 6.8%. Aortic wall desmosine fell by 85.4% in the vehicle-treated rats (1210.6 +/- 87.8 pmol/sample to 176.7 +/- 33.4 pmol/sample; P <.05) but only by 65.6% in the animals treated with RS 312908 (416.2 +/- 120.5 pmol/sample). In contrast, hydroxyproline was not significantly affected by either elastase perfusion or drug treatment. Microscopic examination revealed the preservation of pericellular elastin and a greater degree of fibrocollagenous wall thickening after MMP inhibition, with no detectable difference in the extent of inflammation.. Systemic MMP inhibition suppresses aneurysmal dilatation in the elastase-induced rodent model of AAA. Consistent with its direct inhibitory effect on various MMPs, RS 132908 promotes the preservation of aortic elastin and appears to enhance a profibrotic response within the aortic wall. Hydroxamate-based MMP antagonists may therefore be useful in the development of pharmacologic approaches to the suppression of AAAs.

Topics: Animals; Aorta, Abdominal; Aortic Aneurysm, Abdominal; Collagen; Desmosine; Disease Models, Animal; Elastin; Hydroxamic Acids; Hydroxyproline; Injections, Intra-Arterial; Injections, Subcutaneous; Male; Metalloendopeptidases; Pancreatic Elastase; Pharmaceutical Vehicles; Protease Inhibitors; Rats; Rats, Wistar

Serine elastases degrade elastin, stimulate vascular smooth muscle cell migration and proliferation, and are associated with myocardial damage. To evaluate the impact of elastase inhibition on cardiovascular development and disease, transgenic mice were created in which the mouse preproendothelin-1 promoter was used to target elafin overexpression to the cardiovascular system. To distinguish the transgene from endogenous elafin, constructs were made incorporating a FLAG sequence; the COOH-terminus FLAG-tagged elafin construct produced a stable, functionally active gene product and was used to create transgenic mice. Consistent with endothelin expression, abundant elafin mRNA was observed in transgenic F1 embryos (embryonic day 13.5) and in adult transgenic mice heart, trachea, aorta, kidney, lung, and skin, but not in liver, spleen, and intestine. Functional activity of the transgene was confirmed by heightened myocardial elastase inhibitory activity. No tissue abnormalities were detected by light microscopy or elastin content. However, injection of 10 plaque-forming units (PFU) of encephalomyocarditis virus resulted in death within 11 days in 10 out of 12 nontransgenic mice compared with one out of nine transgenic littermates. This reduced mortality was associated with better cardiac function and less myocardial inflammatory damage. Thus, elafin expression may confer a protective advantage in myocarditis and other inflammatory diseases.

Topics: Animals; Cardiovirus Infections; Cattle; Cells, Cultured; Disease Models, Animal; Elastin; Encephalomyocarditis virus; Endothelin-1; Endothelins; Endothelium, Vascular; Gene Expression; Humans; Mice; Mice, Transgenic; Myocarditis; Myocardium; Pancreatic Elastase; Protein Precursors; Proteinase Inhibitory Proteins, Secretory; Proteins; Pulmonary Artery; Recombinant Fusion Proteins; Serine Proteinase Inhibitors; Sheep; Tissue Distribution

Elastin, an abundant structural protein present in the arterial wall, is prone to calcification in a number of disease processes including porcine bioprosthetic heart valve calcification and atherosclerosis. The mechanisms of elastin calcification are not completely elucidated. In the present work, we demonstrated calcification of purified elastin in rat subdermal implants (Ca(2+) = 89.73 +/- 9.84 microgram/mg after 21 days versus control, unimplanted Ca(2+) = 0.16 +/- 0.04 microgram/mg). X-ray diffraction analysis along with resolution enhanced FTIR spectroscopy demonstrated the mineral phase to be a poorly crystalline hydroxyapatite. We investigated the time course of calcification, the effect of glutaraldehyde crosslinking on calcification, and mechanisms of inhibition of elastin calcification by pretreatment with aluminum chloride (AlCl(3)). Glutaraldehyde pretreatment did not affect calcification (Ca(2+) = 89.06 +/- 17.93 microgram/mg for glutaraldehyde crosslinked elastin versus Ca(2+) = 89.73 +/- 9.84 microgram/mg for uncrosslinked elastin). This may be explained by radioactive ((3)H) glutaraldehyde studies showing very low reactivity between glutaraldehyde and elastin. Our results further demonstrated that AlCl(3) pretreatment of elastin led to complete inhibition of elastin calcification using 21-day rat subdermal implants, irrespective of glutaraldehyde crosslinking (Ca(2+) = 0.73-2.15 microgram/mg for AlCl(3) pretreated elastin versus 89.73 +/- 9.84 for untreated elastin). The AlCl(3) pretreatment caused irreversible binding of aluminum ions to elastin, as assessed by atomic emission spectroscopy. Moreover, aluminum ion binding altered the spatial configuration of elastin as shown by circular dichroism (CD), Fourier transform infrared (FTIR), and (13)C nuclear magnetic resonance (NMR) spectroscopy studies, suggesting a net structural change including a reduction in the extent of beta sheet structures and an increase in coil-turn conformations. Thus, it is concluded that purified elastin calcifies in rat subdermal implants, and that the AlCl(3)-pretreated elastin completely resists calcification due to irreversible aluminum ion binding and subsequent structural alterations caused by AlCl(3).

Topics: Aluminum Chloride; Aluminum Compounds; Amino Acids; Animals; Calcinosis; Cattle; Chlorides; Circular Dichroism; Disease Models, Animal; Durapatite; Elastin; Glutaral; Implants, Experimental; Magnetic Resonance Spectroscopy; Rats; Skin; Spectroscopy, Fourier Transform Infrared; X-Ray Diffraction

We designed an effective quadruple staining protocol that combines histochemistry (HC) and double-labeling immunohistochemistry (IHC: IHC) to stain simultaneously several different morphological features and cell types in vascular lesions. Morphometric image analysis to quantitate vascular wall thickening, lumen area, and proliferating smooth muscle cells on consecutive serial sections is adequate, but morphometric precision and dependable cellular characterization and co-localization could be obtained if analyses are performed on one tissue section. The development of a neointima in the rat carotid artery was induced by angioplasty with a balloon catheter. Tissues were stained for elastin by a modified van Gieson method, then processed for double-labeling IHC:IHC for proliferating cell nuclear antigen and smooth muscle actin followed by hematoxylin staining. The four resulting tissue stains labeled elastin filaments black, proliferating nuclei brown, smooth muscle actin red and nonproliferating nuclei blue. Our staining protocol improved the descriptive and quantitative analysis of relation between smooth muscle cell proliferation and protein expression. Also, neointimal thickening could be measured to analyze its relation to cellular proliferation. Providing one slide with four stains maximizes the information from a single slice of tissue, reduces slide preparation and analysis time, and overcomes the restriction of tissue sample availability. This technique can be applied to a wide spectrum of morphologic and morphometric studies.

Topics: Actins; Alkaline Phosphatase; Angioplasty, Balloon; Angioplasty, Balloon, Coronary; Animals; Biomarkers; Carotid Arteries; Carotid Stenosis; Disease Models, Animal; Elastin; Endothelium, Vascular; Hematoxylin; Immunohistochemistry; Indicators and Reagents; Male; Muscle Fibers, Skeletal; Muscle, Smooth, Vascular; Proliferating Cell Nuclear Antigen; Rats; Rats, Sprague-Dawley; Staining and Labeling

Evidence from in vitro and in vivo studies indicates that damaged elastic fibers can be repaired.. Lipid interstitial pulmonary fibroblasts were cultured for 6 weeks. Cultures were then exposed to 25 microg of porcine pancreatic elastase and fixed in pairs (control, elastase-treated) immediately after exposure and at 1, 2, 3, 4, 7, 10, 14, and 22 days for ultrastructural examination. Elastin was also analyzed biochemically for resistance to hot alkali, an indicator of repair. Steady-state levels of tropoelastin and lysyl oxidase mRNA at 2, 4, and 7 days after elastase treatment were determined by Northern blot analysis.. Immediately after exposure to elastase, damaged elastic fibers exhibited a frayed, porous appearance and a granular texture. Through day 4, fibers showed no evidence of repair. By day 7, the granular texture of damaged fibers was no longer evident and a gradual filling-in of porous areas appeared to be taking place. By 22 days, elastic fibers were indistinguishable from elastic fibers in control cultures. The ultrastructural changes were paralleled by changes in hot alkali resistance. Through day 4, there was no change in the level of hot alkali resistant elastin. Between day 4 and day 7, resistance to hot alkali increased sharply and continued to increase at a slower rate, reaching 84% of the control level by day 22. Steady-state levels of tropoelastin and lysyl oxidase mRNA showed no increase over control levels at 2, 4, and 7 days after elastase treatment.. Elastic fibers synthesized by lipid interstitial pulmonary fibroblasts in culture were repaired after damage by elastase. This type of repair may have relevance to the prevention of pathological conditions, such as emphysema.

Topics: Animals; Cells, Cultured; Disease Models, Animal; Elastic Tissue; Elastin; Fibroblasts; Lung; Lung Injury; Microscopy, Electron; Pancreatic Elastase; Protein-Lysine 6-Oxidase; Pulmonary Emphysema; Rats; RNA, Messenger; Time Factors; Tropoelastin

Treatment of hamster lungs with porcine pancreatic elastase (PPE) causes emphysema and a decrease in lung elastin content, which returns to control level by Day 30. To explore the mechanism of alveolar wall remodeling after elastolytic injury, we examined the expression of elastin and alpha1(I) collagen mRNAs by in situ hybridization at 1, 2, 3, 5, 7, and 30 d after intratracheal PPE. The lungs of control animals displayed weak signals for elastin and alpha1(I) collagen mRNA in pleura, large arteries, veins, and airways. There was little or no signal in respiratory air space walls. Increased expression of elastin and alpha1(I) collagen mRNA began by Day 1 after PPE and reached an asymptote by Day 3 that was maintained by elastin until Day 7; expression of alpha1(I) collagen mRNA waned earlier. Elastin and, to a lesser extent, alpha1(I) collagen mRNA were heavily expressed in pleura, blood vessels, and airways. Analysis of serial sections showed elastin message was minimal in the walls of respiratory air spaces and when present, at 3, 5, and 7 d, was primarily found at the free margins of alveolar septa. Collagen message was very sparse in respiratory air space walls. By 30 d, elastin mRNA expression was reduced but still above control levels and emphysema was widespread and severe. Rank score of elastin mRNA expression in individual subpleural air spaces showed a positive correlation with air space size. In conclusion, most expression of elastin and alpha1(I) collagen mRNA occurs in the pleura, airway, and vascular walls. In respiratory air space walls, expression of elastin mRNAs occurs in damaged tissue at free septal margins.

Topics: Animals; Collagen; Cricetinae; Disease Models, Animal; Elastin; In Situ Hybridization; Lung; Male; Pancreatic Elastase; Pulmonary Alveoli; Pulmonary Emphysema; RNA, Messenger

Abdominal aortic aneurysms are characterised by changes in the extracellular matrix of the arterial media, in particular a reduction in elastin concentration. These changes are mediated by increased levels of endogenous matrix metalloproteinases (MMPs). Recently, calcium channel blockers have been shown to increase the proteolytic activity of MMP-2 secreted by vascular smooth muscle cells. It may therefore by hypothesised that calcium antagonists may potentiate the activity of MMPs in aneurysmal disease and thus accelerate AAA expansion. In this study, the ability of amlodipine--a calcium antagonist--to influence elastin degradation, was assessed in a previously described model of aneurysmal disease.. Porcine aortic segments (n = 8) were pre-incubated in exogenous pancreatic elastase for 24 h prior to culture in standard conditions for 6 days with 10 and 100 micrograms/l amlodipine. Control segments were cultured both with and without amlodipine and without elastase. At the termination of culture MMPs were extracted from the tissue and quantified by a combination of substrate gel enzymography and immunoblotting. The volume fractions of elastin and collagen were determined by stereological analysis of EVG stained sections.. Gel enzymography demonstrated significantly increased MMP-9 activity in the amlodipine treated segments, median 4.218 vs. 2.809 arbitrary units (p < 0.01) and this elevated activity was reflected in a significant destruction of medial elastin 27.0 vs. 40.5% (p < 0.05).. Therapeutic ranges of amlodipine significantly enhanced elastin degradation and potentiated MMP-9 activity within the aortic organ cultures.

Topics: Amlodipine; Animals; Aorta; Aortic Aneurysm; Calcium Channel Blockers; Collagenases; Disease Models, Animal; Elastin; In Vitro Techniques; Matrix Metalloproteinase 9; Swine

Hyperhomocysteinemia is a risk factor for arterial diseases, and the deterioration of the arterial elastic structures is one of the possible mechanisms underlying this epidemiological association. The aim of this paper is to quantitatively characterize such structural alterations and to explore their causes in a previous model of dietary induced mild hyperhomocysteinemia in minipigs. After four months, both a morphodensitometrical analysis of the elastic structure and a biochemical analysis of elastin and elastase activities were performed on the infrarenal abdominal aorta (IRAA) and the proximal left interventricular coronary artery (LIVCA) of control (C), hyperhomocysteinemic (H) and captopril-hydrochlorothiazide (Cp-Htz, 25 + 12.5 mg/d)-treated (H+/-Cp) minipigs (n = 8/group). Hyperhomocysteinemia was found to induce an increase in parietal elastolytic metalloproteinase activities. It resulted in opening and enlargement of fenestrae through the medial elastic laminae and in a decrease in medial elastin content (p < 10(-3)), expressed as well as volume density (%) as weight concentration (microg elastin/mg dry tissue). The thickness of the media and its basic lamellar organization was unchanged. The reduction in volume density was more dramatic in LIVCA (H: 4.7 +/- 0.9 vs C: 8.8 +/- 2.4), where it was evenly distributed within the media, than in IRAA (H: 6.7 +/- 1.1 vs C: 9.3 +/- 1.2), where the deep medial layers were less affected. Cp-Htz partly prevented the hyperhomocysteinemia-induced reduction of the medial elastin content in LIVCA (5.7 +/- 1.2) and IRAA (7.9 +/- 1.4). This effect, occurring in the subintimal layers of the media in both arteries but not in the deeper layers, resulted in a less beneficial effect in LIVCA than in IRAA. This result parallels the moderate beneficial therapeutic effect of ACE inhibitors against coronary atherosclerosis in humans. This paper reports for the first time a quantitative analysis of the arterial site-dependent deterioration of the elastic structure caused by mild hyperhomocysteinemia and the involvement of metalloproteinases in this process. These results confirm that the plaque-independent damage to elastic structure previously described in hyperhomocysteinemic-atherosclerotic minipigs was mainly due to homocysteine. This highlights that the metalloproteinase-related elastolysis and the subsequent structural deterioration is one of the major events underlying the epidemiological association between mild hyp

Topics: Animals; Antihypertensive Agents; Aorta, Abdominal; Captopril; Coronary Vessels; Disease Models, Animal; Elastic Tissue; Elasticity; Elastin; Hydrochlorothiazide; Hyperhomocysteinemia; Swine; Swine, Miniature

Topics: alpha 1-Antitrypsin; alpha 1-Antitrypsin Deficiency; Animals; Animals, Newborn; Disease Models, Animal; Elastin; Emphysema; Humans; Leukocyte Elastase; Mice; Mice, Inbred BALB C; Mice, Inbred C57BL; Mice, Mutant Strains; Microscopy, Immunoelectron; Pulmonary Alveoli

The structure of porcine skin as examined by light microscopy is reviewed and its similarities to and differences from human skin are highlighted. Special imaging techniques and staining procedures are described and their use in gathering morphological information in porcine skin is discussed. Confocal laser scanning microscopy (CLSM) was employed to examine the structure of porcine skin and the findings are presented as an adjunct to the information already available in the literature. It is concluded that CLSM provides valuable additional morphological information to material examined by conventional microscopy and is useful for wound healing studies in the porcine model.

Topics: Animals; Collagen; Coloring Agents; Disease Models, Animal; Elastin; Epidermis; Female; Macrophages; Mast Cells; Microscopy, Confocal; Muscle, Smooth; Skin; Swine; Wound Healing

Infusion of the abdominal aorta with pancreatic elastase induces aneurysms in a rat model (Anidjar/Dobrin). Because elastolysis liberates elastin degradation products (EDPs), the present experiment was carried out to test the hypothesis that an EDP alone could induce features of aneurysm disease.. The EDP val/gly/val/ala/pro/gly (VGVAPG), elastase, or saline solution was infused into infrarenal aorta (n = 4/group). After 1 week aortic diameters were measured, and the tissues were prepared for histologic examination. Adventitial capillaries (vessels per high-power field) were counted over a standardized preparation of aorta. Wall thickness was measured by means of computer-aided planimetry.. There was an increase of greater than 100-fold in mean vessels per high-power field in aortas receiving VGVAPG or elastase versus saline controls (4.10 +/- 0.68 SEM or 4.48 +/- 0.49 SEM versus 0.03 +/- 0.03 SEM, respectively, p < 0.05). The VGVAPG-perfused group had a 26% +/- 4% SEM increase in diameter from baseline that was statistically significant (p < 0.01), but the aortas did not reach aneurysmal dimensions.. Although no aneurysms occurred at 1 week after the infusion of EDP, the results demonstrate that the EDP VGVAPG can induce a characteristic feature of aneurysm disease. The model permits study of the earliest stages of experimental aneurysm formation and raises interesting questions regarding the role of the vasa vasorum in this pathologic process.

Topics: Animals; Aortic Aneurysm, Abdominal; Disease Models, Animal; Elastin; Muscle, Smooth, Vascular; Neovascularization, Pathologic; Oligopeptides; Rats; Rats, Wistar

A novel amino acid named aldosine was isolated from acid hydrolysates of bovine aorta elastin. The mass spectral analysis of aldosine indicated a parent compound with a mass of 256 (C12H20N2O4). From the structure identified by spectroscopy of aldosine and its derivatives, it was deduced that aldosine was derived from aldol crosslink and dehydromerodesmosine of elastin and collagen. The aldosine content in aorta of newborn rats was very low, but increased markedly with growth. After maturity was reached, the aldosine content decreased. The aldosine content in bovine aorta decreased gradually from 7 months to 16 years of age. Aldosine was also quantified in the aorta and tail tendon of rats in two models of hyperglycemia: diabetes and galactosemia. Hyperglycemias were significantly affected on aldosine content of organs. In both diabetic and galactosemic animals, aldosine was remarkably lower relative to controls (about one-half and one-sixth, respectively).

Topics: Aging; Amino Acids; Animals; Aorta; Cattle; Collagen; Cross-Linking Reagents; Diabetes Mellitus, Experimental; Disease Models, Animal; Elastin; Galactosemias; Hyperglycemia; Magnetic Resonance Spectroscopy; Male; Molecular Structure; Piperidines; Pyridines; Rats; Rats, Sprague-Dawley; Tendons; Tissue Distribution

Increased local production of matrix metalloproteinases (MMPs) is a potential mechanism underlying structural protein degradation in abdominal aortic aneurysms (AAA). With an elastase-induced rodent model of AAA, we determined whether pharmacologic treatment with an MMP-inhibiting tetracycline might limit the development of experimental AAA in vivo.. Forty-eight Wistar rats underwent a 2-hour perfusion of the abdominal aorta with 50 U porcine pancreatic elastase and were then treated with either subcutaneous doxycycline (25 mg/day; n=24) or saline solution vehicle (n=24). Aortic diameter was measured before and after elastase perfusion was performed and before the rats were killed at 0, 2, 7, or 14 days, and AAAs were defined as an increase in aortic diameter to at least twice that before perfusion. At death the aortic tissues were either perfusion-fixed for histologic evaluation or extracted for substrate zymographic evaluation.. Aortic diameter was not different between groups at 0 or 2 days, but it was significantly less in animals treated with doxycycline at both 7 and 14 days (mean+/-SEM, p<0.01). After day 2 the incidence of AAA was reduced from 83% (10 of 12 rats treated with saline solution) to 8% (1 of 12 animals treated with doxycycline). By histologic assessment doxycycline prevented the structural deterioration of aortic elastin without decreasing the influx of inflammatory cells. Increased aortic wall production of 92 kD gelatinase observed in a saline solution-treated control group was markedly suppressed in animals treated with doxycycline.. Treatment with an MMP-inhibiting tetracycline inhibits the development of experimental AAA in vivo. This inhibition may be due to selective blockade of elastolytic MMP expression in infiltrating inflammatory cells. Additional experiments, however, are necessitated to fully delineate this process.

Topics: Animals; Anti-Bacterial Agents; Aorta, Abdominal; Aortic Aneurysm, Abdominal; Disease Models, Animal; Disease Progression; Doxycycline; Elastin; Enzyme Inhibitors; Gelatinases; Injections, Subcutaneous; Male; Pancreatic Elastase; Rats; Rats, Wistar; Sodium Chloride; Swine

The relationship between elastin degradation and emphysema is well known. Recent evidence suggests that a complex process of pulmonary remodeling occurs within the emphysematous lung. The aim of this study was to assess the extent of extracellular matrix remodeling in emphysema by ultrastructural examination of elastin and collagen templates in an animal model of emphysema and in human emphysematous lungs. Emphysema was induced in rats by the intratracheal administration of porcine pancreatic elastase. Human lung samples were obtained at surgical resection for lung carcinoma. Emphysema was confirmed morphometrically and quantitated using the mean linear intercept. Matching sections were treated with sodium hydroxide and formic acid to expose collagen and elastin templates, respectively. Scanning electron microscopy with stereo-pair imaging allowed three-dimensional visualization of the exposed templates. In emphysematous lungs from both sources, sheets of elastin were disrupted and perforated with multiple fenestrations. In elastase-induced emphysema, this disintegration was accompanied by a marked increase in thickness of collagen fibrils, which contrasted with the fine fibrillar network of control lungs. Similarly, a pattern of thickened fibrils and disorganized deposition of collagen was observed in human lungs. In conclusion, these findings support the novel concept of increased collagen deposition and aberrant collagen remodeling in the pathogenesis of emphysema.

Topics: Animals; Bronchoalveolar Lavage Fluid; Collagen; Disease Models, Animal; Elastin; Emphysema; Female; Humans; Lung; Microscopy, Electron, Scanning; Pancreatic Elastase; Rats; Rats, Sprague-Dawley

The Ishibashi (IS) rat, established from cross-breeding between Wistar and wild rats, has a unique skin appearance, with wrinklings and furrows indicative of skin aging appearing at the age of 12 weeks. To understand the underlying mechanism of the formation of wrinkles, macromolecular components of connective tissue, collagen and elastin, in the young (5-6-week-old) and the aged (23-30-week-old) IS rat skins were biochemically analyzed. Hydroxyproline and isodesmosine contents in the aged IS rats were reduced 22% (P < 0.05) and 37% (P < 0.05) compared to the young rats, whereas no significant differences in the contents of both macromolecules in control Sprague-Dawley (SD) rats were seen. The relative content of type III collagen was unaltered between the young and aged skins of both IS and SD rats. A relative decrease in the intact elastin molecule (65 kDa) and a relative increase in the elastin fragments with lower molecular weights were observed in the aged IS rat skin by immunoblotting method. These results indicate that the reduction in collagen and elastin contents and increased degradation of elastin molecules in the aged IS rat skin could be related to the formation of wrinkles. Thus, the IS rat may provide a useful model for the study of skin aging.

Topics: Aging; Animals; Animals, Wild; Collagen; Connective Tissue; Disease Models, Animal; Elastin; Macromolecular Substances; Male; Rats; Rats, Sprague-Dawley; Rats, Wistar; Skin

Topics: Aging; Amino Acids; Animals; Aortic Rupture; Cartilage, Articular; Collagen; Collagen Diseases; Disease Models, Animal; Disease Progression; Elastin; Enzyme-Linked Immunosorbent Assay; Female; Femur; Male; Mice; Mice, Inbred C57BL; Osteoarthritis; Protein-Lysine 6-Oxidase; Stifle; Tibia

Topics: Animals; Aortic Aneurysm, Abdominal; Disease Models, Animal; Elastin; Neovascularization, Pathologic; Oligopeptides; Rats; Rats, Wistar; Vasa Vasorum

Hairless (SKH-1) mice were mated with Beige (C57B/bb) mice to produce a hairless mouse deficient in neutrophil elastase (hhbb). These mice were exposed to 0.09J UVB irradiation for 5 months to see if neutrophil elastase was an important factor in elastin remodeling and development of solar elastoses. Analysis of peritoneal neutrophils confirmed that the hhbb mouse was deficient in elastase, retaining only 10% as much activity as the normal littermates (hhHb). Skin MPO activity was equally elevated in all the mice receiving UVB suggesting an equal influx of inflammatory cells. The absolute breaking strength of the skin in both the hhBb and hhbb mice was not altered by UVB treatment over the 5 month exposure period. Elastin quantitated biochemically as desmosine, or visualized histologically, was increased following UVB exposure in the normal mice. In the elastase deficient mice, however, the elastin fibers appeared to be unaffected by exposure to UVB irradiation at this level. The results suggest that neutrophil elastase is an important mediator in the development of solar elastosis resulting from continued exposure to UVB irradiation.

Topics: Animals; Chemotaxis, Leukocyte; Desmosine; Disease Models, Animal; Disease Progression; Elasticity; Elastin; Female; Male; Mice; Mice, Hairless; Neutrophils; Pancreatic Elastase; Skin; Skin Aging; Skin Diseases; Ultraviolet Rays; Up-Regulation

The purpose of this study was to determine whether the presence of bowel in the chest during development in the fetal lamb model of congenital diaphragmatic hernia (CDH) results in structural and/or biochemical hypoplasia of the left venticle.. The model was created at 80 days' gestation and delivered at term. The hearts were fixed in 4% formaldehyde solution, components weighed, and right ventricular (RV) and left ventricular (LV) wall thicknesses and both aortic (Ao) and pulmonary artery (PA) root diameters were measured. Fresh specimens were analyzed for protein, DNA, hydroxyproline, and elastin content. All CDH measurements are compared with littermate control tissues.. There were no differences in body weight (kg) between CDH and control littermates (4.25 +/- 0.26 versus 3.71 +/- 0.24, P = NS). CDH lambs have significantly decreased total heart (4.88 +/- .25 versus 6.75 +/- .49, P < .05), left ventricular (1.65 +/- .11 versus 2.15 +/- .19, P < .05), septal (1.29 +/- .11 versus 1.99 +/- .21, P < .05), and combined atrial (0.68 +/- .06 versus 1.14 +/- .15, P < .05) weights (g/kg lamb) without differences in RV weights (1.26 +/- .07 versus 1.57 +/- .17, P = NS). LV and RV wall thickness, and Ao root diameters (cm) were found to be identical in both CDH and control lambs. However, PA root diameters (0.47 +/- .01 versus 0.38 +/- .01, P < .005) and ductus arteriosus diameters were increased in CDH (0.35 +/- .01 versus 0.22 +/- .02, P < .005). Total protein, DNA collagen, and elastin content and DNA/total protein ratios were identical in RV and LV in both CDH and control lambs.. Newborn lambs with left-sided CDH have a significantly lower total heart, LV, septal, and atrial weights without differences of RV weight or ventricular wall thicknesses. Given these findings, the unchanged DNA/protein ratio implies that the left ventricle is hypoplastic in CDH. Ao/PA root ratios suggest that LV hypoplasia in utero may result in increased left atrial pressures, decreased right-to-left shunting through the foramen ovale, and increased PA pressures and flow, resulting in increased PA root and ductus arteriosus diameters. This model simulates the clinical data from human fetuses/neonates with CDH. Further investigations are necessary to determine the functional significance of these findings.

Topics: Animals; Aorta; Blood Pressure; Collagen; Disease Models, Animal; DNA; Ductus Arteriosus, Patent; Elastin; Female; Heart Atria; Heart Defects, Congenital; Heart Septal Defects, Atrial; Heart Septum; Heart Ventricles; Hernia, Diaphragmatic; Hernias, Diaphragmatic, Congenital; Humans; Hydroxyproline; Organ Size; Pregnancy; Proteins; Pulmonary Artery; Sheep

The pathophysiologic features of congenital diaphragmatic hernia (CDH) include pulmonary hypoplasia, pulmonary hypertension, surfactant deficiency, and decreased pulmonary compliance. When the surfactant deficiency is corrected using exogenous surfactant therapy, the pulmonary compliance improves, but does not reach normal values. Quasistatic saline pressure-volume measurements, which eliminate the air-liquid interface, confirm that CDH lungs are intrinsically less compliant than control lungs. The authors hypothesized that this abnormal lung compliance results from elevated concentrations of collagen and/or elastin in the lung. Therefore, they measured the collagen and elastin concentrations in CDH and control lung tissue. Also measured was the collagen concentration in the kidney, intestine, and dissected third-generation arterioles, venules, and bronchioles, to characterize further the pathology of CDH. The CDH model was created on the left side of fetuses in pregnant ewes at 80 days' gestation. The fetuses were delivered and killed at 140 days (full term, 145). The concentrations of collagen (as hydroxyproline), elastin, DNA, and total protein were measured using standard techniques. Although there was significantly more collagen per gram of lung tissue in the CDH lungs (1.334 mg/g v 0.885 mg/g in the controls) the elastin concentrations were not different. The elevated collagen concentration was not associated specifically with the conducting airways or vasculature. The collagen concentrations in CDH kidneys and intestines were the same as those of controls. The DNA/total protein ratios in the CDH and control lungs were identical. The results suggest that the elevated collagen concentration was present only in the lungs of CDH lambs, and that it was not attributable to atrophy or hypertrophy of the lungs. Thus, increased collagen in the lung parenchyma may be responsible for the intrinsic stiffness and decreased compliance of the CDH lungs.

Topics: Animals; Arterioles; Bronchi; Collagen; Disease Models, Animal; DNA; Elastin; Female; Gestational Age; Hernia, Diaphragmatic; Hernias, Diaphragmatic, Congenital; Humans; Hydroxyproline; Infant, Newborn; Intestines; Kidney; Lung; Lung Compliance; Persistent Fetal Circulation Syndrome; Pregnancy; Proteins; Pulmonary Surfactants; Sheep; Venules

According to a current hypothesis, pulmonary emphysema results from damage to the elastic fiber network caused by an imbalance within the lower respiratory tract between elastase(s) and protease inhibitors. This hypothesis is based largely on studies of persons with genetic deficiency of serum alpha 1-proteinase inhibitor. We recently reported a spontaneously occurring emphysema in the pallid mouse with an inherited deficiency of serum alpha 1-proteinase inhibitor. This animal reproduces important features of the human condition. We describe here the changes in alveolar elastolytic burden and in the bronchoalveolar lavage (BAL) cell population, which precede and accompany the development of emphysema in pallid mice.. A possible correlation between the levels of lung elastase burden and the loss of lung elastin content was investigated in the period of development of emphysema in pallid mice. Changes in alveolar cells were investigated for specimens from BAL fluids and lung tissue by cytologic, histologic, and immunogold-electron microscopic methods.. An immunogold-positive reaction for elastase was observed on elastin within the alveolar walls of pallid mice from 2 months onward. The average of gold particle density progressively increased with age, reaching high values at 12 and 16 months of age, the age at which parenchymal destruction was previously reported to occur. Lung elastin content had normal values at 2, 4, and 8 months of age. However, it was significantly lower at 12 and 16 months of age. The immunogold values of elastase burden correlated inversely with the decrease in lung elastin content. Total and differential cell counts from BAL fluids of pallid mice did not differ significantly at any time in life and were similar to age-matched controls. However, in pallid mice from 8 months of life onward, pulmonary macrophages contained characteristic intracytoplasmic crystalloid inclusions, which were electrondense and bounded by a single membrane. Using electron microscopy and an immunogold-labeling technique with anti-mouse I-III collagen IgG, these inclusions were identified as collagen-derived products.. The data reported in this paper suggest that emphysematous lesions in pallid mice are associated with a progressive increase of elastase in alveolar intestitium and with loss of lung elastin. Surprisingly, the number of neutrophils in BAL fluids does not increase with the increase of lung elastolytic burden. However, intracytoplasmic crystalloid inclusions related to collagen degradation were observed in pulmonary macrophages of pallid mice at the time of septal disruption. The presence of similar structures in alveolar macrophages from mice or other animal species may be indicative of connective tissue breakdown or remodeling of tissue collagen.

Topics: alpha 1-Antitrypsin Deficiency; Animals; Bronchoalveolar Lavage Fluid; Disease Models, Animal; Elastin; Leukocyte Elastase; Lung; Male; Mice; Mice, Inbred C57BL; Pancreatic Elastase; Pulmonary Emphysema

We developed a new biomaterial designed to replaced loss of tympanic tissue. This new material has an original collagen-elastin structure which can be used to create an new artificial conjunctive matrix. The concept and the first experimental results are reported.

Topics: Animals; Biocompatible Materials; Collagen; Disease Models, Animal; Elastin; Materials Testing; Rabbits; Tympanoplasty

An elastin peptide (kE57) obtained from organoalkaline hydrolysis of calf ligamentum nuchae insoluble elastin, was isolated by gel permeation on Sephadex G150 and high performance liquid chromatography on a TSK G 3000 SW column. It possessed an average Mr = 57,000 and similar amino acids composition as its insoluble counterpart. kE57 behave as a competitive inhibitor of human neutrophil elastase (HNE) with Ki = 1.4 microM; it also inhibited porcine pancreatic elastase (PPE) but less efficiently Ki = 180 microM. Identification of elastic fibres in rat gingiva was ascertained by light and electron microscopic studies. Morphometric studies indicated that rat gingiva contained similar levels of elastic fibres (= 2%) as human skin; elastic fibres networks from both tissues also displayed high structural analogy. Gingival chronic inflammation was induced in rats by mechanical impaction associated with an hyperglucidic diet. After 5 weeks, the levels of rat gingiva elastic fibres, decreased from Vv = 1.94 +/- 0.1% to Vv = 1.02 +/- 0.06%. Local injections of kE57: 100 micrograms per day, 5 days a week for 5 weeks did restore the integrity of the gingiva elastic fibres network: Vv = 1.84 +/- 0.1. Without influencing leucocyte infiltration, it is proposed that elastin-derived peptides, acting as potent competitive inhibitor of neutrophil elastase involved in periodontitis, might be of therapeutic value.

Topics: Animals; Cattle; Chronic Disease; Connective Tissue; Disease Models, Animal; Elastic Tissue; Elastin; Gingivitis; Humans; Leukocyte Elastase; Pancreatic Elastase; Peptide Fragments; Rats; Swine

The evaluation of various techniques to diagnose or exclude ventilator-associated bacterial pneumonia has been a focus of much research. One such technique involves elastin fiber detection. It has been inferred from previous work that 40% potassium hydroxide preparations of respiratory secretions that demonstrate elastin fibers have a 100% specificity in diagnosing bacterial pneumonia in intubated, mechanically ventilated patients without acute diffuse lung injury. The purpose of this investigation was to ascertain if elastin fibers might be detected in respiratory secretions in acute, diffuse lung injury in the absence of pneumonia (i.e., assess specificity).. An animal model using a standardized smoke inhalation protocol to cause acute, diffuse lung injury was used.. Respiratory secretions collected from the endotracheal tubes from eight sheep that underwent the standardized smoke inhalation protocol and were examined with 40% potassium hydroxide. Histologic data were obtained from autopsy to diagnose or exclude lung injury and pneumonia.. We found six (false) positive elastin fiber preparations in the absence of histologic pneumonia. Specificity was 0.25.. We concluded that seeing these results, given a true specificity of 0.99 inferred from previous work, is highly improbable with a probability of 2.74 x 10(-7). Thus, elastin fiber analysis is likely to be highly nonspecific for diagnosing pneumonia in the setting of acute diffuse lung injury.

Topics: Acute Disease; Animals; Disease Models, Animal; Elastin; False Positive Reactions; Lung; Pneumonia, Bacterial; Respiratory Distress Syndrome; Sensitivity and Specificity; Sheep; Smoke Inhalation Injury

The effect of exogenous surfactant treatment on lung and type II cell structure of ventilated lambs of 137-138 days gestational age was studied. Thirty-four lambs were delivered and randomized to control or 100 mg/kg of natural sheep surfactant treatment groups. Lungs from one group of lambs not treated with surfactant were fixed before ventilation, and the other animals were ventilated to maintain normal blood gas values for 3, 24, or 48 h. Morphometric assessment of the inflation-fixed lung parenchyma of ventilated lungs was compared with the architectural appearance of alveoli and alveolar ducts in the unventilated lungs. Mechanical ventilation resulted in distension of alveolar ducts accompanied by the shallowing and loss of well-defined alveoli and areas of atelectasis at 3 h. These abnormalities increased in severity after 24 and 48 h of ventilation. Surfactant treatment before ventilation significantly reduced the extent and degree of dilatation and concomitant atelectasis. The fraction of normal parenchyma was 38 +/- 7% in untreated lambs vs. 64 +/- 6% in treated lambs after 24 h of ventilation. After 48 h of ventilation, significant differences between control (39 +/- 6%) and surfactant-treated (55 +/- 6%) lambs were still evident. Alveolar type II cells contained approximately 15% lamellar bodies by volume. Neither surfactant treatment nor time of ventilation altered the volume density of lamellar bodies or other organelles, except for a decrease in glycogen from 8% in nonventilated lungs to 2.5% in lungs ventilated for 24 h. These findings indicate that a surfactant treatment at birth results in the maintenance of more normal parenchyma with less atelectasis during prolonged ventilation of the immature lung.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animals; Animals, Newborn; Blood Gas Analysis; Collagen; Disease Models, Animal; Elastin; Humans; Infant, Newborn; Lung; Microscopy, Electron, Scanning; Pulmonary Alveoli; Pulmonary Atelectasis; Pulmonary Surfactants; Random Allocation; Respiration, Artificial; Respiratory Distress Syndrome, Newborn; Sheep

The Watanabe hereditary hyperlipidemic (WHHL) rabbit is an animal model that resembles humans with familial hyperlipidemia. In the thoracic aortae, there is also morphologic evidence of marked destruction of medial lamellar elastin fibers. Herein is provided the chemical evidence of elastolytic degradation. The levels of lysyl oxidase (L.Ox.), soluble elastin (SE) and insoluble elastin (IE) were estimated in thoracic aortae samples from New Zealand white (NZW) and WHHL rabbits at 6 months of age or 5 WHHL rabbits at 2.5 years of age. Enzyme-linked immunosorption assays (ELISA) were used in the L.Ox. and SE measurements. IE was measured following alkali extraction of aortae. There was a decrease in IE in thoracic aortae from Watanabe rabbits compared to NZW controls at 6 months of age (P < 0.1), and a further loss of IE in aortae from 2.5-year-old WHHL rabbits relative to the values at 6 months (P < 0.05). Average values for IE were: 130 mg/g for 6-month-old NZW, 100 mg/g for 6-month-old WHHL, and 60 mg/g for 2.5-year-old WHHL rabbits. Moreover, SE was only observed in aorta extracts from the older WHHL rabbits, a sign of elastolytic damage. There was also a five- to sixfold decrease in L.Ox. in the older vs. younger rabbits.

Topics: Aging; Animals; Aorta; Disease Models, Animal; Elastin; Enzyme-Linked Immunosorbent Assay; Hyperlipidemias; Protein-Lysine 6-Oxidase; Rabbits; Solubility

Elastin is an important component of normal blood vessels and the extracellular matrix of atherosclerotic plaques, but its role in intimal thickening in the arteries of transplanted organs has not been defined. We have looked at elastin gene expression (by in situ mRNA hybridization) in an animal model using an abdominal aortic transplant between 2 strains of rats disparate for MHC class I antigens. The normal aortic wall of adult rats lacks elastin mRNA. Aortic allografts at 7 days after transplantation exhibit increased elastin mRNA in the medial vascular smooth muscle cells. This medial elastin mRNA expression is present only until 20 days after transplantation, and at later times, only the juxtaluminal cells of the neointima express elastin mRNA. Stainable elastin is detectable only in regions that previously demonstrated high levels of elastin mRNA. Combined in situ hybridization and immunocytochemistry reveals that most elastin mRNA-expressing cells in the media are alpha-actin-positive smooth muscle cells. In the neointima, elastin mRNA-expressing cells do not stain with antibodies to either smooth muscle alpha-actin or macrophage proteins. This cell population may represent a "synthetic" phenotype of vascular smooth muscle cell lacking alpha-actin protein. We presume there is immune cell-mediated injury leading to a vascular smooth muscle cell response and part of the vascular smooth muscle cell response may be increased elastin mRNA expression and elastin deposition in the allografts.

Topics: Actins; Animals; Aorta, Abdominal; Arteries; Disease Models, Animal; Elastin; Gene Expression; Graft Rejection; Immunohistochemistry; In Situ Hybridization; Male; Muscle, Smooth, Vascular; Rats; RNA, Messenger; Time Factors

One-month-old male New Zealand White rabbits were fed either a cholesterol-free casein diet (n = 10) or low-level cholesterol-supplemented chow (n = 10) for 24 weeks, during which total plasma cholesterol levels were matched. After perfusion fixation, aortic tissue samples were taken from six predetermined locations and embedded in epoxy resin for examination by light and electron microscopy. Frozen sections were also obtained for histochemical demonstration of collagen and elastin. Lesion morphology was classified in toluidine blue-stained, semithin epoxy sections as early fatty streaks (round foam cells with little intervening extracellular matrix); advanced fatty streaks (foam cells with extracellular lipid); fibrous plaques (spindle-shaped cells within extracellular matrix); or atheromatous lesions (presence of an atheromatous core). In representative specimens, electron microscopy showed that the ultrastructure of round foam cells was consistent with macrophage derivation, whereas most spindle-shaped cells were clearly smooth muscle cells. Fibrous plaques were more common in the distal than the proximal aorta. Lesions in the casein-fed animals were essentially equally distributed among the four morphological categories, whereas lesions in the cholesterol-fed rabbits were predominantly of the atheromatous type. Thus, cholesterol-fed rabbits had, in general, more advanced lesions than casein-fed rabbits with matched total plasma cholesterol levels. Moreover, the feeding of a low-level cholesterol diet (0.125% to 0.5% by weight) to rabbits for a relatively short time (6 months) led to the development of advanced lesions similar to those seen in humans.

Topics: Animals; Aorta; Arteriosclerosis; Caseins; Cholesterol; Cholesterol, Dietary; Collagen; Dietary Proteins; Disease Models, Animal; Elastin; Histocytochemistry; Male; Microscopy, Electron; Rabbits

Sprague-Dawley rats were exposed for 6 h daily to 0.8 ppm of ozone and 14.4 ppm of nitrogen dioxide. Approximately 7 to 10 wk after the initiation of exposure, animals began to demonstrate respiratory insufficiency and severe weight loss. About half of the rats died between Days 55 and 78 of exposure; no overt ill effects were observed in animals exposed to filtered air, to ozone alone, or to nitrogen dioxide. Biochemical findings in animals exposed to ozone and nitrogen dioxide included increased lung content of DNA, protein, collagen, and elastin, which was about 300% higher than the control values. The collagen-specific crosslink hydroxy-pyridinium, a biomarker for mature collagen in the lung, was decreased by about 40%. These results are consistent with extensive breakdown and remodeling of the lung parenchyma and its associated vasculature. Histopathologic evaluation showed severe fibrosis, alveolar collapse, honeycombing, macrophage and mast cell accumulation, vascular smooth muscle hypertrophy, and other indications of severe progressive interstitial pulmonary fibrosis and end-stage lung disease. This unique animal model of progressive pulmonary fibrosis resembles the final stages of human idiopathic pulmonary fibrosis and should facilitate studying underlying mechanisms and potential therapy of progressive pulmonary fibrosis.

Topics: Administration, Inhalation; Animals; Collagen; Desmosine; Disease Models, Animal; DNA; Elastin; Environmental Exposure; Hydroxyproline; Lung; Male; Nitrogen Dioxide; Ozone; Proteins; Pulmonary Fibrosis; Pyridines; Rats; Rats, Sprague-Dawley; Survival Rate

The current hypothesis of pulmonary emphysema is based on an alteration of the protease-antiprotease balance within the lower respiratory tract. This hypothesis derives largely from studies in emphysema patients with genetic deficiency in serum alpha 1-antitrypsin. In animals, naturally occurring deficiency in serum elastase inhibitory capacity associated with early development of emphysema has been reported in the tight-skin mouse. We describe here a mouse model of genetic deficiency of alpha 1-antitrypsin in which emphysema occurs late in life.. A genetic deficiency in serum alpha 1-antitrypsin was investigated in pallid mice, a strain with spontaneous occurring emphysema. Additionally, the possible pathogenetic role of an elastase-anti-elastase imbalance in pallid mice was investigated using molecular biologic, biochemical, histologic, ultrastructural, and immunoelectron microscopic methods.. Pallid mice have markedly low levels of serum alpha 1-antitrypsin associated with a severe deficiency in serum elastase inhibitory capacity. However, they have normal alpha 1-antitrypsin mRNA levels in the liver. At ultrastructural examination, disruption of alveolar septa is first seen at 8 months of age. At histologic examination, some patchy areas of air-space enlargement with destruction of alveolar septa are seen from 12 months of age onward. These histologic changes are paralleled by a decrease in lung elastin content. The development of the pulmonary lesions is preceded by an alveolar elastolytic burden detected by an immunogold technique.. All these data suggest that the lung changes in pallid mice are the result of an elastolytic process due to a severe inborn deficiency of serum alpha 1-antitrypsin. This animal model reproduces important features of the human condition and may provide new insights into the pathogenesis of emphysema.

Topics: alpha 1-Antitrypsin; alpha 1-Antitrypsin Deficiency; Animals; Base Sequence; Disease Models, Animal; Elastin; Lung; Male; Mice; Mice, Inbred BALB C; Mice, Inbred C57BL; Microscopy, Electron; Microscopy, Immunoelectron; Molecular Sequence Data; Pancreatic Elastase; Pulmonary Alveoli; Pulmonary Emphysema

Topics: Animals; Chromosome Mapping; Collagen; Collagen Diseases; Disease Models, Animal; Elastin; Genes; Humans; Mice; Phenotype; Research Design; United States

We have previously studied the process of calcification in bioprosthetic porcine heart valves crosslinked with glutaraldehyde. Observations using light microscopy had indicated that calcification of elastic fibers occurs in implanted heart valves, in addition to calcification associated with collagen fibers. To determine the contribution of elastin to the process of calcification, small pieces of rabbit aorta were cross-linked with 0.2% glutaraldehyde, rinsed in buffer, and implanted subcutaneously in young adult male rats. Cross-linked jugular vein implants were included as controls. After an implantation period of 1 month or longer, we observed many areas of calcification in the aortic media associated with elastin and fewer such areas associated with collagen. The elastin-rich aortic tissues accumulated more calcium than venous tissues. Calcium deposits appeared similar in both allogenic and xenogeneic implants. Calcified areas viewed under the electron microscope included intercellular nonfibrous material. Calcified areas involved predominantly the outer layers of elastic fibers. Calcific deposits included needle-like crystals of hydroxyapatite but often consisted of an amorphous flocculant material surrounded by crystals. The close spatial relationship of hydroxyapatite crystals and elastic membranes seen in this study may be relevant to the initiation of dystrophic calcification in glutaraldehyde cross-linked aortic grafts.

Topics: Animals; Calcinosis; Calcium; Cross-Linking Reagents; Disease Models, Animal; Elastin; Glutaral; Male; Microscopy, Electron; Prostheses and Implants; Rabbits; Rats; Vascular Diseases

Transgenic mice were generated that expressed a human collagenase transgene in their lungs under the direction of the haptoglobin promoter. Histological analysis demonstrated disruption of the alveolar walls and coalescence of the alveolar spaces with no evidence of fibrosis or inflammation. This pathology is strikingly similar to the morphological changes observed in human emphysema and therefore implicates interstitial collagenase as a possible etiological agent in the disease process. Although elastase has been proposed as the primary enzyme responsible for emphysematous lung damage, this study provides evidence that other extracellular matrix proteases could play a role in emphysema. In addition, these transgenic mice are a defined genetic animal model system to study the pathogenesis of emphysema.

Topics: Animals; Cells, Cultured; Collagen; Collagenases; Disease Models, Animal; Elastin; Emphysema; Haptoglobins; Humans; Lung; Mice; Mice, Transgenic; Promoter Regions, Genetic

To elucidate whether tissue fibronectin increases in the early stages of atherogenesis induced by hypercholesterolemia without mechanical trauma, we investigated sequential changes in the distribution of tissue fibronectin during fatty streak initiation and maturation in the aortas of hypercholesterolemic fat-fed rabbits. The presence of fibronectin was examined on immunoperoxidase stained tissue specimens with the aid of a microscope-photometric technique. Twenty male albino rabbits were used. Cholesterol supplemented chow (1%) was given for 4 weeks (n = 6), 8 (n = 5) or 14 weeks (n = 5). A membrane-like layer positive for fibronectin was observed along the endothelium in the normal aorta. After 4 weeks of the cholesterol-feeding, fatty streaks were initiated in the intima, where fibronectin was more densely accumulated than the normal intima. After 8 weeks of the cholesterol-feeding, fatty streaks were expanding, associated with the dense staining for fibronectin. After 14 weeks, fibronectin was still concentrated in the endothelial layer and also in the superficial areas of the thickened intima, but decreased in the deep areas of the thickened intima where collagen and elastin appeared as bundles. The photometric data of fibronectin supported these visual observations. Thus, fibronectin appeared early and disappeared later in the intima during the process of fatty streak initiation and maturation. These findings suggest that in hypercholesterolemia without mechanical endothelial injury, fibronectin may play an important role in an early process of atherogenesis.

Topics: Animals; Aorta; Arteriosclerosis; Collagen; Diet, Atherogenic; Disease Models, Animal; Elastin; Endothelium, Vascular; Fibronectins; Hypercholesterolemia; Immunohistochemistry; Male; Rabbits

Using light microscopic immunohistochemistry, we studied the immunolocalization and immunoreactivity of the extracellular matrix, including collagen types III, IV, VI, laminin, and alpha elastin in the lamina cribrosa of monkey eyes with normal and experimentally chronic glaucoma. Our results showed: (1) abnormal linearlike immunodeposits of both collagen type IV and laminin in the margin of the lamina cribrosa with significant density in the glaucomatous eyes; (2) the immunoreactivity of collagen type III resembled that of the normal eye, but was slightly stronger at the laminar surface; (3) findings with collagen type VI resembled those of type III with an enhanced linearlike staining surrounding the nerve-fiber bundles. Furthermore, staining of alpha elastin demonstrated dramatic changes in both reactivity and localization. The lamina cribrosa of glaucomatous eyes showed a markedly reduced immunoreactivity as well as an irregular, interrupted pattern. These observations suggest that the changes might be a secondary to the long-standing elevation of intraocular pressure. The alteration of these macromolecules may modify the course of glaucomatous optic damage.

Topics: Animals; Chronic Disease; Collagen; Disease Models, Animal; Elastin; Extracellular Matrix; Fundus Oculi; Glaucoma; Immunoenzyme Techniques; Intraocular Pressure; Laminin; Laser Therapy; Macaca fascicularis; Optic Disk

Current theories of pathogenesis suggest that pulmonary emphysema develops in humans because of progressive loss or derangement of lung elastin through a process mediated by elastolytic enzymes released by inflammatory cells. Neutrophils are considered primary etiologic factors because these cells produce and release two potent serine proteinases that cause emphysema when instilled into the lungs of animals. It has been suggested that alveolar macrophages also contribute to the development of emphysema through production of several enzymes with elastolytic activity, including the lysosomal cysteine proteinases cathepsin B and cathepsin L, but this has not been verified experimentally. In the current study, we instilled 115 micrograms of active cathepsin B into the lungs of hamsters three times at 48-h intervals. After 6 wk microscopic evaluation revealed that lung sections of five of seven animals given cathepsin B contained focal areas of enlarged and distorted alveoli, in the absence of fibrosis, which were similar to changes seen in the lungs of animals given papain intratracheally. Morphometrically, mean linear intercept (micron) values were significantly higher (p less than 0.025) in animals given cathepsin B (204.4 +/- 20.8) as compared with control animals (173.2 +/- 7.8), and internal surface area (sqcm) values were significantly lower (935 +/- 120 versus 1,083 +/- 56 in control animals), thereby confirming that airspace enlargement had developed after instillation of the enzyme. Lung volumes (ml) and compliance (ml/cm H2O) were not significantly higher in animals given cathepsin B.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animals; Bronchoalveolar Lavage Fluid; Cathepsin B; Cricetinae; Disease Models, Animal; Elastin; Instillation, Drug; Lung; Male; Mesocricetus; Papain; Pulmonary Emphysema; Trachea

Topics: Animals; Disease Models, Animal; Elastin; Enzyme-Linked Immunosorbent Assay; Humans; Peptide Fragments; Pulmonary Emphysema

Disruption and degradation of interstitial elastic fibers are significant characteristics of pulmonary emphysema. In order to examine the responses of elastogenic cells to the conditions mimicking degradation of interstitial pulmonary elastin, rat pulmonary fibroblast cultures were used as an in vitro model. Second passage fibroblasts were divided into two different environmental situations to represent cells adjacent to and remote from the site of elastase-digested matrix. One set of cell cultures was briefly digested with pancreatic elastase. The resultant digest was then added back incrementally to the medium of elastase-digested cell cultures and to the medium of a second set of undigested cultures. Both sets of cell cultures remained viable and metabolically active during these treatments (96 h of incubation) as judged by protein synthesis, cell number, and steady-state levels of beta-actin mRNA. However, the two sets of cultures exhibited opposite responses in elastin gene expression with addition of increasing amounts of the elastase digest. The elastase-digested cultures exhibited a 200% increase in extractable soluble elastin and a 186% increase in tropoelastin mRNA with the addition of increasing amounts of the elastase digest to the medium. Conversely, the amount of soluble elastin recovered from the undigested cultures decreased 75%, and the steady-state level of tropoelastin mRNA decreased 63%. Soluble elastin peptides generated from oxalic acid treatment of purified elastin were shown to decrease tropoelastin mRNA in undigested cell cultures in the same manner as the elastase digest. Based on these data, we propose that pulmonary fibroblast elastin gene expression can be controlled coordinately by the state of the extracellular matrix and solubilized peptides derived from that matrix. Such integrated regulation may serve to localize elastin repair mechanisms.

Topics: Actins; Animals; Animals, Newborn; Cells, Cultured; Disease Models, Animal; DNA; Elastin; Emphysema; Fibroblasts; Gene Expression Regulation; Lung; Rats; RNA, Messenger; Tropoelastin

The occluded canine tail artery, which comes off in the same plane as the aortoiliac junction, has been used as a flow model for cerebral aneurysms. These experiments were designed to determine if it is a realistic distensible model of human intracranial aneurysms. Distensibility studies were done on the aorta, and the iliac and tail arteries of four dogs. From these pressure-volume studies, tension-strain curves, elastances, and collagen slack were obtained. The tail artery is stiffer longitudinally and more distensible circumferentially than the other vessels. The iliac arteries and the aorta are not significantly different. The elastance of elastin and collagen is lower in the tail artery, and the collagen is more wavy circumferentially. Longitudinally, the collagen slack is least for the tail artery, and the elastance of elastin is not different in all three vessels. The number of elastin layers in the iliac and tail arteries seen in cross section is not significantly different, but the aorta is different from both these vessels. In another four dogs the aorta proximal to the trifurcation was cannulated and infused with saline to increase pressure. India ink marks were put on the surface to measure changes in length. Photographs were taken at intervals of 10 mmHg(1 mmHg = 133.3 Pa). This was done with the vessels tethered and untethered in the body and then taken out and studied with the same method in vitro. Arteries tethered in the body expanded circumferentially more than longitudinally. The tail artery becomes less distensible if untethered in the body and therefore acts more like an aneurysm.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animals; Aorta; Arteries; Collagen; Disease Models, Animal; Dogs; Elasticity; Elastin; Iliac Artery; Intracranial Aneurysm; Microscopy, Electron, Scanning; Regional Blood Flow; Staining and Labeling; Tail

The tight-skin (Tsk) mouse has recently been proposed as a genetic model of emphysema. In the present study, the development of emphysema was investigated in these mice with histological, biochemical, and ultrastructural methods at 4 days and at 1 and 2 months of life. At 4 days after birth, histological examination of the lungs revealed only a mild enlargement of the primary sacculi. Neither biochemical nor ultrastructural changes were seen however at this time. At 1 month of age, the histological examination showed marked emphysema-like changes, characterized by enlargment of air spaces accompanied by destruction of alveolar walls. Biochemical analysis showed a marked decrease in insoluble elastin content and a significant increase in salt-extractable collagen. Ultrastructural investigation revealed edema fluid in the interstitium and broken and disorganized elastic fibers. All these findings strikingly resemble the changes which occur in the lungs early after an instillation of elastase. In the 2-month-old Tsk mice the histological lesion progressed in severity. The ultrastructural findings were similar to those observed at 1 month, and the biochemical changes showed no signs of recovery. Thus, in these mice, the emphysematous lesion develops very rapidly between 4 days and 1 month of life and shows the characteristics of an elastolytic process which is still ongoing at 2 months of age.

Topics: Animals; Collagen; Disease Models, Animal; Elastin; Emphysema; Female; Lung; Male; Mice; Mice, Inbred C57BL; Microscopy, Electron

We evaluated the effect of beta-aminopropionitrile (beta APN) on the nitrogen dioxide (NO2) animal model of emphysema. Rats maintained on a beta APN-supplemented or a regular diet were exposed to 30 ppm NO2 for intervals ranging from 1 to 8 wk. Emphysema development was assessed by histologic evaluation and by changes in lung volume and mean linear intercept values. Evidence of pathologic changes were also documented by clinical and radiographic findings of osteolathyrism. The induction of centriacinar emphysema was attributed specifically to NO2 exposure. Neither the severity of the emphysema nor the time course of its development was altered by the beta APN-supplemented diet. These findings are in marked contrast to those observed with the exogenous elastase model of the disease, and they suggest that elastin synthesis and repair may not modulate elastin destruction in the NO2 model of emphysema.

Topics: Aminopropionitrile; Analysis of Variance; Animals; Diet; Disease Models, Animal; Elastin; Germ-Free Life; Lathyrism; Lung; Male; Nitrogen Dioxide; Organ Size; Pulmonary Emphysema; Rats; Rats, Inbred Strains; Time Factors

We suggest that hypoxia-induced pulmonary hypertension in the newborn calf is an attractive model for studying the mechanisms underlying alterations in extracellular matrix accumulation which occur in pulmonary vascular disease. Our data support a model (Fig 7) in which the SMC, perhaps as a result of hypoxic and/or pressure-induced vessel wall injury, becomes phenotypically altered. This phenotypically altered SMC generates a factor, termed smooth muscle derived extracellular matrix factor (SMEF), and possibly other factors. SMEF, in turn, stimulates or induces elastin and collagen synthesis in fibroblasts and endothelial cells. SMEF, or an associated activity derived from phenotypically altered smooth muscle cells, also induces elastin receptor expression on the cell surface and affects the chemotactic responsiveness of vascular cells. Thus, the SMC may be able to affect both the secretory and responsive properties of cell types in the vascular wall. The SMC may be critical in the vascular remodeling in pulmonary hypertension. The possible autocrine or paracrine alteration of cellular phenotypes by smooth muscle-derived mediators provides an important new direction for future research into molecular and cellular mechanisms of connective tissue regulation in diseased vessels.

Topics: Altitude; Animals; Animals, Newborn; Cattle; Cattle Diseases; Collagen; Disease Models, Animal; Elastin; Hypertension, Pulmonary; Hypoxia; Muscle, Smooth, Vascular; Phenotype; Pulmonary Artery

To study the morphologic alterations of pulmonary elastic fibers in cynomolgus monkeys with paraquat toxicity, peroxidase- and ferritin-labeled antielastin antibodies were used for the light and electron microscopic localization of elastin. One week after paraquat, alveolitis, tissue damage and alveolar dilatation were present; elastic fibers were frayed and more diffusely and intensely stained than those of control animals. In the latter, staining was localized in peripheral regions of the amorphous components and, to a lesser extent, in some microfibrils of elastic fibers. At 3 to 4 weeks, diffuse staining was evident in damaged interstitial elastic fibers and in newly formed elastic fibers in areas of intraalveolar fibrosis. At 8 weeks, the interstitium contained many elastic fibers which showed staining only in peripheral regions of the amorphous components. These observations suggest that: 1) preembedding immunohistochemical staining for elastin is localized in peripheral regions of normal elastic fibers because the antielastin antibody can penetrate into mature and undamaged amorphous components only to a very limited extent; 2) in early stages of paraquat toxicity this staining is more diffuse and intense because elastase from inflammatory cells partially degrades the elastic fibers and permits greater penetration of the antibody into the amorphous materials; 3) in later stages the staining pattern returns to normal as inflammation subsides and elastic fibers are repaired; however, newly formed elastic fibers in areas of intraalveolar fibrosis stain diffusely, reflecting increased penetration of the antibody because of immaturity and incomplete cross-linking, and 4) degeneration of elastic fibers of alveolar walls in paraquat lung may lead to alveolar dilatation, which is associated with irregular fibrosis and constitutes one of the processes of pulmonary structural remodeling in paraquat lung.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animals; Disease Models, Animal; Elastin; Immunohistochemistry; Lung; Macaca fascicularis; Microscopy, Electron; Paraquat; Pulmonary Fibrosis

Pulmonary emphysema is a major public health problem and is primarily a disease of smokers. The pathogenesis of emphysema in smokers is likely to be multifactorial and may involve protease-antiprotease imbalance, abnormal host response to injury, the inactivation of antiproteases by oxidants, and direct damage of lung tissue by pulmonary phagocytes. The data regarding current concepts of pathogenesis of emphysema in smokers are reviewed in this article.

Topics: alpha 1-Antitrypsin; Blood Proteins; Disease Models, Animal; Elastin; Humans; Lung; Monocytes; Neutrophils; Pancreatic Elastase; Protease Inhibitors; Pulmonary Emphysema; Smoking

Abnormal accumulation of connective tissue in blood vessels contributes to alterations in vascular physiology associated with disease states such as hypertension and atherosclerosis. Elastin synthesis was studied in blood vessels from newborn calves with severe pulmonary hypertension induced by alveolar hypoxia in order to investigate the cellular stimuli that elicit changes in pulmonary arterial connective tissue production. A two- to fourfold increase in elastin production was observed in pulmonary artery tissue and medial smooth muscle cells from hypertensive calves. This stimulation of elastin production was accompanied by a corresponding increase in elastin messenger RNA consistent with regulation at the transcriptional level. Conditioned serum harvested from cultures of pulmonary artery smooth muscle cells isolated from hypertensive animals contained one or more low molecular weight elastogenic factors that stimulated the production of elastin in both fibroblasts and smooth muscle cells and altered the chemotactic responsiveness of fibroblasts to elastin peptides. These results suggest that connective tissue changes in the pulmonary vasculature in response to pulmonary hypertension are orchestrated by the medial smooth muscle cell through the generation of specific differentiation factors that alter both the secretory phenotype and responsive properties of surrounding cells.

Topics: Animals; Cattle; Connective Tissue; Disease Models, Animal; Elastin; Humans; Hypertension, Pulmonary; Hypoxia; Muscle, Smooth, Vascular; RNA, Messenger; Transcription, Genetic

The nonelastolytic proteases trypsin and chymotrypsin were administered to hamsters 24 hours after intratracheal injection of elastase. Severity of the disease, extent of degradation and resynthesis, new cross-link formation, and the levels of the enzyme lysyl oxidase, which mediates the cross-link formation, were compared with the same parameters measured in hamsters with experimental emphysema induced by elastase alone. Increases in mean linear intercept indicated that a more severe form of the disease was produced. Although elastin degradation after 1 week was similar in both groups, resynthesis of the elastin destroyed by the elastolytic insult was significantly impaired in the animals injected sequentially with elastase and trypsin or chymotrypsin. Formation of new elastin as monitored by 14C-lysine incorporation into the elastin specific cross-links desmosine and isodesmosine was reduced approximately 40%, although there was no significant difference in the levels of lysyl oxidase activity. It is suggested that the most likely mechanism compatible with the recorded observations involves destruction of the microfibrillar component of the elastic fiber by trypsin or chymotrypsin, resulting in the absence of the requisite template for resynthesis of the pulmonary elastin.

Topics: Animals; Chymotrypsin; Cricetinae; Desmosine; Disease Models, Animal; Elastin; Female; Isodesmosine; Lung; Lysine; Mesocricetus; Pancreatic Elastase; Protein-Lysine 6-Oxidase; Pulmonary Emphysema; Trypsin

A mild form of emphysema was produced in pigs raised on a copper-deficient, zinc-supplemented diet. The copper-requiring enzyme, lysyl oxidase, catalyzes the cross-linking of tropoelastin into mature elastin. Zinc further inhibits the activity of lysyl oxidase. Lungs from animals raised on copper-deficient, zinc-supplemented diets of demonstrate perforations in alveolar walls and diminished amounts of elastin bronchi and pulmonary arteries. Mean linear intercepts are greater and alveolar internal surface areas are less than those in control animals, fulfilling the generally accepted definition of emphysema. Physiologic confirmation is provided by a leftward shift of the saline volume-pressure curves when compared with those in control animals. Ultrastructurally, the alveolar walls are effaced and pores of Kohn are enlarged. There are areas in which elastin is absent leaving remnant microfibrils, and there are other changes consistent with active elastin synthesis. Biochemical data demonstrate no difference in elastin content as micrograms/ml of fat-free dry weight but do demonstrate increased collagen content in experimental animal lungs compared with that in control lungs. Ultrastructural similarities to enzyme-induced models of emphysema suggest the presence of elastin degradation in our model. We speculate that although the copper-deficient, zinc-supplemented state may stimulate protein synthesis in general, elastin is being degraded by endogenous means, but collagen is not.

Topics: Air Pressure; Animals; Collagen; Copper; Diet; Disease Models, Animal; Elastin; Lung; Lung Volume Measurements; Organ Size; Protein-Lysine 6-Oxidase; Pulmonary Emphysema; Swine; Zinc

Vascular structural changes were studied during the development of two-kidney one-clip renal hypertension. The weight of the arteries and the concentration and total amount of ribonucleic acid, deoxyribonucleic acid, alkali-soluble proteins, collagen and elastin of the vascular wall were measured. Tritiated thymidine uptake was also determined 15 and 30 days after clipping. Hypertension developed in 58% of the animals while the rest remained normotensive. A significant increase in artery weight and in the total amount of nucleic acids and proteins was found in hypertensive rats. The uptake of 3H thymidine by the arteries of hypertensive rats was significantly increased 15 days after clipping. This increment showed a significant correlation with blood pressure levels. Present data seem to indicate that the increase in vessel wall dimensions observed is partly due to an increase in the number of smooth muscle cells during the acute phase; this alteration appears to be mainly due to the rise in blood pressure.

Topics: Animals; Blood Pressure; Cardiomegaly; Collagen; Disease Models, Animal; DNA; Elastin; Hyperplasia; Hypertension, Renal; Hypertension, Renovascular; Male; Muscle, Smooth, Vascular; Myocardium; Rats; Rats, Inbred Strains; RNA; Thymidine

Topics: Animals; Cricetinae; Disease Models, Animal; Dose-Response Relationship, Drug; Elastin; Lung; Pancreatic Elastase; Pulmonary Emphysema; Time Factors

Fibromuscular dysplasia (FMD) was found in 24 of 31 turkeys studied. This is the first species other than man in which FMD has been reported. FMD in turkeys simulates lesions variously known as fibromuscular dysplasia, fibromuscular hyperplasia, and medial hyperplasia in man. It occurred in turkeys from 8 weeks to 1 year of age and was evenly distributed between the sexes (11 males, 13 females). FMD in turkeys is a disease of arterioles and small arteries 44 mu to 666 mu in diameter. A lesion of more than 2.6 mm in length (in an artery 0.1 mm in diameter) was encountered. An adherent thrombus over 670 mu long was seen attached to an FMD lesion. Angiopathy appears to be basic to the pathogenesis of FMD and is characterized by endothelial hyperplasia, smooth-muscle vacuolization, and patchy necrosis of the media.

Topics: Animals; Arterial Occlusive Diseases; Arteries; Disease Models, Animal; Elastin; Female; Fibromuscular Dysplasia; Male; Muscles; Musculoskeletal System; Turkeys

Topics: Animals; Cobalt Radioisotopes; Collagen; Disease Models, Animal; DNA; Elastin; Haplorhini; Lung; Lung Volume Measurements; Papio; Pulmonary Alveoli; Pulmonary Fibrosis; Radiation Injuries, Experimental

Based on the hypothesis that cross-linked elastin is critical for normal lung structure, lung tissue from copper-deficient rats was studied. Copper deficiency was induced in the second generation by feeding dams a milk-based diet low in copper (less than 1 ppm) during gestation and lactation. The weanlings were fed the same diet until they showed severe signs of deficiency between 6 and 10 weeks of age. Controls animals received the basal diet supplemented with 10 ppm copper. Liver cytochrome oxidase activity, which served as the chief index of deficiency, decreased from a normal level of approximately 80 to 15 mumole/min/g. The lungs of the deficient animals contained 17% less elastin and had 35% larger alveolar spaces (34.7 vs 47.7 intercepts), as determined by the mean alveolar intercept method. The ultrastructure of elastin in the bronchi, arterioles, and alveolar ducts had a "washed out" appearance. To determine the reversibility of the pathology, deficient animals, 5 to 10 weeks of age, were repleted by feeding a copper-supplemented diet for 1, 2, and 3 months. During this period growth resumed, anemia disappeared, and liver cytochrome oxidase returned to normal. There was no improvement in lung structure with regard to alveolar size (28.4 intercepts compared with 43.6 in controls and 35.1 in deficient littermates killed at the start of repletion). The ultrastructure and electron density of pulmonary elastin was restored to near normal. The lung of the copper-deficient rat is proposed as a model for developmental pulmonary emphysema.

Topics: Animals; Arterioles; Bronchi; Copper; Diet; Disease Models, Animal; Elastin; Electron Transport Complex IV; Female; Liver; Lung; Male; Pulmonary Alveoli; Pulmonary Emphysema; Rats; Rats, Inbred Strains

Topics: Animals; Collagen; Disease Models, Animal; Elastin; Hemorrhage; Inflammation; Intubation, Intratracheal; Lung; Lung Diseases; Papain; Pulmonary Edema; Pulmonary Emphysema; Rabbits

Young growing rats were intraperitoneally injected with mixtures of homocystine and methionine for several weeks. The growth of the animals was inhibited. After 3 weeks 25% of the rats died and isolation of tail tendon collagen and aorta elastin showed that these proteins were deficient in chemical cross-links. Seventy-five % of the rats survived further injections for another 3 weeks and isolated collagen and elastin were found to be normal in cross-linking. The variability in susceptibility of these rats to homocystine-methionine treatment is discussed in relationship to human homocystinuria. It is speculated that the variability is due to variability in in vivo homocysteine levels.

Topics: Animals; Collagen; Connective Tissue; Disease Models, Animal; Elastin; Female; Homocystine; Homocystinuria; Humans; Male; Methionine; Peptides; Rats; Solubility

Full-thickness square wounds were made in the webs of fruit bats. Elastin was laid down in the healing scars of these wounds in two forms--as single fibers under the regenerated epidermis, and as bundles of fine fibers taking their origin and orientation from the cut ends of the web elastin bundles. This process continued over a period of 6 months, during which time other components of the scar became reduced in amount. The arrangement of the new elastin in the scar tissue was thus a replica of that seen in the normal web. There are indications in this study that elastin imparts elasticity to the scar.

Topics: Animals; Chiroptera; Cicatrix; Disease Models, Animal; Elastin; Regeneration; Skin; Skin Physiological Phenomena; Wound Healing; Wounds and Injuries

Topics: alpha 1-Antitrypsin; Animals; Apgar Score; Disease Models, Animal; Elastin; Female; Fetal Hypoxia; Fetal Membranes, Premature Rupture; Gestational Age; Guinea Pigs; Haplorhini; Humans; Hyaline Membrane Disease; Infant, Newborn; Lung; Pregnancy; Pulmonary Surfactants; Respiratory Distress Syndrome, Newborn; Retrospective Studies; Sheep

Japanese quail were investigated for their utility as a model for the discovery and evaluation of anti-atherosclerosis compounds. Although they possessed suitable characteristics for a screening animal, their development of atherosclerosis was too variable to make them a practical model. A search was conducted to find a means to make quail uniformly atherosclerotic. To this end a line of quail susceptible to experimental atherosclerosis (SEA) were selectively bred. Thus, the SEA Japanese quail is a new animal model for atherosclerosis research.

Topics: Animals; Arteriosclerosis; Cholesterol, Dietary; Cholic Acids; Coturnix; Disease Models, Animal; Elastin; Female; Humans; Male; Quail; Sex Factors; Species Specificity

Vascular collagen and elastin contents and the ratio of collagen/elastin (C/E) were studied in racing greyhound dogs, a breed which exhibits increased cardiac output. As compared to mongrel dogs, vascular C/E was lower, suggesting a greater distensibility of vessels as an adaptive response to hemodynamic stress.

Topics: Animals; Arteries; Collagen; Disease Models, Animal; Dogs; Elastin; Hydroxyproline; Running

Topics: Animals; Aorta, Thoracic; Aortic Diseases; Arteriosclerosis; Collagen; Coronary Disease; Coronary Vessels; Diet, Atherogenic; Disease Models, Animal; Eggs; Elastin; Endothelium; Female; Femoral Artery; Hypercholesterolemia; Iliac Artery; Inclusion Bodies; Male; Marsupialia; Meat; Microscopy, Electron

Topics: Alanine; Animals; Arginine; Benzoates; Butanols; Cricetinae; Disease Models, Animal; Elastic Tissue; Elastin; Esters; Ethanol; Injections; Lung; Nitrophenols; Papain; Pulmonary Emphysema; Spectrometry, Fluorescence; Trachea

Topics: Aminopropionitrile; Animals; Aorta, Abdominal; Arteries; Body Weight; Collagen; Disease Models, Animal; Edema; Elastin; Female; Ferrocyanides; Haplorhini; Hemorrhage; Hemosiderosis; Iliac Artery; Lathyrism; Macaca; Male; Sternum; Thoracic Arteries

Topics: Aerosols; Animals; Disease Models, Animal; Elastin; Histocytochemistry; Lung; Lung Compliance; Male; Microscopy, Electron; Microscopy, Interference; Papain; Pulmonary Emphysema; Rats; Reticulin

Topics: Animals; Aorta, Abdominal; Arteries; Arteriosclerosis; Basement Membrane; Disease Models, Animal; Elastic Tissue; Elastin; Epithelium; Hydrochloric Acid; Microscopy, Electron; Muscle, Smooth; Rats