elastin and Emphysema

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

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: Catalase; Connective Tissue; Elastin; Emphysema; Free Radicals; Humans; Lung; Lung Injury; Macrophages; Monocytes; Neutrophils; Nutrition Disorders; Nutritional Physiological Phenomena; Pancreatic Elastase; Protease Inhibitors; Protein Biosynthesis; Superoxide Dismutase

To better define the role of mechanical forces in pulmonary emphysema, we employed methods recently developed in our laboratory to identify microscopic level relationships between airspace size and elastin-specific desmosine and isodesmosine (DID) cross links in normal and emphysematous human lungs. Free DID in wet tissue (a biomarker for elastin degradation) and total DID in formalin-fixed, paraffin-embedded (FFPE) tissue sections were measured using liquid chromatography-tandem mass spectrometry and correlated with alveolar diameter, as determined by the mean linear intercept (MLI) method. There was a positive correlation between free lung DID and MLI (

Topics: Elastin; Emphysema; Humans; Lung; Pulmonary Alveoli; Pulmonary Emphysema

To establish a model of emphysema induced by tobacco smoke combined with elastin peptides (EP), explore the biochemical metabolic processes and signal transduction pathways related to emphysema occurrence and development at the transcriptional level, and identify new targets and signaling pathways for emphysema prevention and treatment.. Mice were randomly divided into the air pseudoexposure group (NORMAL group) and the tobacco smoke + EP group (EP group). The differentially expressed genes (DEGs) in lung tissue between the two groups were identified by RNA-seq, and functional annotation and Gene Ontology (GO)/ Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were performed. The differential expression of the selected genes were verified using qRT‒PCR and immunohistochemistry (IHC).. EP group mice showed emphysema-like changes. The expression levels of 1159 genes in the EP group differed significantly (529 up-regulated and 630 down-regulated) from those in the NORMAL group. GO enrichment analysis showed that the DEGs were significantly enriched in the terms immune system, adaptive immune response, and phosphorylation, while KEGG pathway enrichment analysis showed that the DEGs were enriched mainly in the pathways cytokine‒cytokine receptor interaction, T-cell receptor signaling pathway, MAPK signaling pathway, Rap1 signaling pathway, endocytosis, chemokine signaling pathway, Th17 cell differentiation, and Th1 and Th2 cell differentiation. The differential expression of the selected DEGs were verified by qRT‒PCR and IHC, and the expression trends of these genes were consistent with those identified by RNA-seq.. Emphysema may be related to the inflammatory response, immune response, immune regulation, oxidative stress injury, and other biological processes. The Bmp4-Smad-Hoxa5/Acvr2a signaling pathway may be involved in COPD/ emphysema occurrence and development.

Topics: Animals; Computational Biology; Cytokines; Elastin; Emphysema; Gene Expression Profiling; Mice; Pulmonary Disease, Chronic Obstructive; Pulmonary Emphysema; Sequence Analysis, RNA; Tobacco Smoke Pollution; Transcriptome

To investigate the role of the CD40-CD40 ligand (CD40L) pathway in the regulation of Th1, Th17, and regulatory T (Treg)-cell responses in an elastin peptide (EP)-induced autoimmune emphysema mouse model.. BALB/c mice were transnasally treated with EP on day 0, injected intravenously with anti-CD40 antibody via the tail vein on day 33, and sacrificed on day 40. The severity of emphysema was evaluated by determining the mean linear intercept (MLI) and destructive index (DI) from lung sections. The proportions of myeloid dendritic cells (mDCs) and Th1, Th17, and Treg cells in the blood, spleen, and lungs were determined via flow cytometry. The levels of the cytokines interleukin (IL)-6, IL-17, interferon (IFN)-γ, and transforming growth factor (TGF)-β were detected via enzyme-linked immunosorbent assay.. CD40. The CD40-CD40L pathway could play a critical role in Th1, Th17 and Treg cell dysregulation in EP-mediated emphysema and could be a potential therapeutic target.

Topics: Animals; CD40 Antigens; CD40 Ligand; Cytokines; Elastin; Emphysema; Forkhead Transcription Factors; Interleukin-17; Mice; Nuclear Receptor Subfamily 1, Group F, Member 3; Peptides; Pulmonary Disease, Chronic Obstructive; Pulmonary Emphysema; Th1 Cells; Th17 Cells

Cigarette smoke (CS), a complex chemical indoor air pollutant, induces degradation of elastin, resulting in emphysema. Aberrant cross-talk between macrophages and bronchial epithelial cells is essential for the degradation of elastin that contributes to emphysema, in which extracellular vesicles (EVs) play a critical role. The formation of N6-methyladenosine (m6A) is a modification in miRNA processing, but its role in the development of emphysema remains unclear. Here, we established that production of excess mature microRNA-93 (miR-93) in bronchial epithelial cells via enhanced m6A modification was mediated by overexpressed methyltransferase-like 3 (METTL3) induced by CS. Mature miR-93 was transferred from bronchial epithelial cells into macrophages by EVs. In macrophages, miR-93 activated the JNK pathway by targeting dual-specificity phosphatase 2 (DUSP2), which elevated the levels of matrix metalloproteinase 9 (MMP9) and matrix metalloproteinase 12 (MMP12) and induced elastin degradation, leading to emphysema. These results demonstrate that METTL3-mediated formation of EV miR-93, facilitated by m6A, is implicated in the aberrant cross-talk of epithelium-macrophages, indicating that this process is involved in the smoking-related emphysema. EV miR-93 may use as a novel risk biomarker for CS-induced emphysema.

Topics: Elastin; Emphysema; Epithelium; Extracellular Vesicles; Humans; Macrophages; Methyltransferases; MicroRNAs; Smoking

Topics: alpha 1-Antitrypsin; Animals; Biomechanical Phenomena; Elastin; Emphysema; Fibroblasts; Gene Expression Regulation, Enzymologic; Humans; Lung; Mice, Knockout; Pancreatic Elastase

Elastin degradation is a key feature of emphysema and may have a role in the pathogenesis of atherosclerosis associated with chronic obstructive pulmonary disease (COPD). Circulating desmosine is a specific biomarker of elastin degradation. We investigated the association between plasma desmosine (pDES) and emphysema severity/progression, coronary artery calcium score (CACS) and mortality.pDES was measured in 1177 COPD patients and 110 healthy control subjects from two independent cohorts. Emphysema was assessed on chest computed tomography scans. Aortic arterial stiffness was measured as the aortic-femoral pulse wave velocity.pDES was elevated in patients with cardiovascular disease (p<0.005) and correlated with age (rho=0.39, p<0.0005), CACS (rho=0.19, p<0.0005) modified Medical Research Council dyspnoea score (rho=0.15, p<0.0005), 6-min walking distance (rho=-0.17, p<0.0005) and body mass index, airflow obstruction, dyspnoea, exercise capacity index (rho=0.10, p<0.01), but not with emphysema, emphysema progression or forced expiratory volume in 1 s decline. pDES predicted all-cause mortality independently of several confounding factors (p<0.005). In an independent cohort of 186 patients with COPD and 110 control subjects, pDES levels were higher in COPD patients with cardiovascular disease and correlated with arterial stiffness (p<0.05).In COPD, excess elastin degradation relates to cardiovascular comorbidities, atherosclerosis, arterial stiffness, systemic inflammation and mortality, but not to emphysema or emphysema progression. pDES is a good biomarker of cardiovascular risk and mortality in COPD.

Topics: Adult; Aged; Biomarkers; Body Composition; Bronchodilator Agents; Calcinosis; Cardiovascular Diseases; Case-Control Studies; Coronary Vessels; Desmosine; Disease Progression; Elastin; Emphysema; Female; Forced Expiratory Volume; Humans; Inflammation; Male; Middle Aged; Pulmonary Disease, Chronic Obstructive; Pulmonary Emphysema; Pulse Wave Analysis; Respiratory Function Tests; Risk Factors; Smoking; Vascular Stiffness

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

Galactosialidosis is a lysosomal storage disorder caused by loss of function of protective protein cathepsin A, which leads to secondary deficiencies of β-galactosidase and neuraminidase-1. Emphysema has not been previously reported as a possible complication of this disorder, but we now describe this condition in a 41-year-old, non-smoking male. Our patient did not display deficiency in α-1-antitrypsin, the most common cause of emphysema in non-smokers, which brings about disseminated elastolysis. We therefore hypothesized that loss of cathepsin A activity was responsible because of previously published evidence showing it is prerequisite for normal elastogenesis. We now present experimental evidence to support this theory by demonstrating impaired primary elastogenesis in cultures of dermal fibroblasts from our patient. The obtained data further endorse our previous finding that functional integrity of the cell surface-targeted molecular complex of cathepsin A, neuraminidase-1 and the elastin-binding protein (spliced variant of β-galactosidase) is prerequisite for the normal assembly of elastic fibers. Importantly, we also found that elastic fiber production was increased after exposure either to losartan, spironolactone, or dexamethasone. Of immediate clinical relevance, our data suggest that surviving patients with galactosialidosis should have periodic assessment of their pulmonary function. We also encourage further experimental exploration of therapeutic potential of the afore-mentioned elastogenesis-stimulating drugs for the alleviation of pathological processes in galactosialidosis that could be mechanistically linked to impaired deposition of elastic fibers.

Topics: Adult; beta-Galactosidase; Cathepsin A; Cells, Cultured; Elastic Tissue; Elastin; Emphysema; Fibrillins; Fibroblasts; Gene Expression; Humans; Lysosomal Storage Diseases; Male; Microfilament Proteins; Neuraminidase

Topics: Elastin; Emphysema; Genetic Predisposition to Disease; Haploinsufficiency; Heart Diseases; Humans

All-trans retinoic acid (ATRA) is controversially discussed in emphysema therapy. We re-evaluated ATRA in the elastase model and hypothesised that beneficial effects should be reflected by increased alveolar surface area, elastin expression and downregulation of inflammatory mediators and matrix metalloproteinases (MMPs). Emphysema was induced by porcine pancreatic elastase versus saline in Sprague-Dawley rats. On days 26-37, rats received daily intraperitoneal injections with ATRA (500 μg · kg(-1) body weight) versus olive oil. Lungs were removed at day 38. Rat alveolar epithelial L2 cells were incubated with/without elastase followed by ATRA- or vehicle-treatment, respectively. ATRA only partially ameliorated structural defects. Alveolar walls exhibited irregular architecture: increased arithmetic mean thickness, reduction in surface coverage by alveolar epithelial cells type II. ATRA only partially restored reduced soluble elastin. It tended to increase the ratio of ED1(+):ED2(+) macrophages. Bronchoalveolar lavage (BAL) cells exhibited a proinflammatory state and high expression of interleukin-1β, cytokine-induced neutrophil chemoattractant-1, tumour necrosis factor-α, nuclear factor-κB, MMP-2, MMP-9, MMP-12, tissue inhibitor of metalloproteinase (TIMP)-1 and TIMP-2 in emphysema, with ATRA exerting only few effects. MMP-7 was highly induced by ATRA in healthy but not in emphysematous lungs. ATRA reduced both MMP-2 and TIMP-1 activity in BAL fluid of emphysematous lungs. ATRA-therapy may bear the risk of unwanted side-effects on alveolar septal architecture in emphysematous lungs.

Topics: Animals; Bronchoalveolar Lavage Fluid; Cell Line; Ectodysplasins; Elastin; Emphysema; Interleukin-1beta; Lung; Macrophages; Male; Matrix Metalloproteinase 12; Matrix Metalloproteinase 2; Matrix Metalloproteinase 7; Matrix Metalloproteinase 9; Pancreatic Elastase; Pulmonary Alveoli; Rats; Rats, Sprague-Dawley; Tissue Inhibitor of Metalloproteinase-1; Tissue Inhibitor of Metalloproteinase-2; Tretinoin; Tumor Necrosis Factor-alpha

Two unrelated adult patients with MPS I (Hurler-Scheie) demonstrated sub-pleural bullous emphysema. This complication of MPS I should be looked for due to the risk of spontaneous pneumothorax.

Topics: Adult; Elastin; Emphysema; Enzyme Replacement Therapy; Humans; Mucopolysaccharidosis I; Phenotype; Pleura; Tomography, X-Ray Computed

The destruction of elastic fibers has been implicated in the pathogenesis of chronic obstructive pulmonary disease (COPD). Emphysema has been described in autosomal dominant cutis laxa, which can be caused by mutations in the elastin gene. Previously, a rare functional mutation in the terminal exon of elastin was found in a case of severe, early-onset COPD. To test the hypothesis that other similar elastin mutations may predispose to COPD, we screened 90 probands from the Boston Early-Onset COPD Study and 90 smoking control subjects from the Normative Aging Study for mutations in elastin exons using high-resolution DNA melt analysis followed by resequencing. Rare nonsynonymous single-nucleotide polymorphisms (SNPs) seen only in cases were examined for segregation with airflow obstruction within pedigrees. Common nonsynonymous SNPs were tested for association with COPD in a family-based analysis of 949 subjects from the Boston Early-Onset COPD Study, and in a case-control analysis in 389 COPD cases from the National Emphysema Treatment Trial and 472 control subjects from the Normative Aging Study. Of 28 elastin variants found, 3 were nonsynonymous SNPs found only in cases. The previously described Gly773Asp mutation was found in another proband. The other two SNPs did not clearly segregate with COPD within families. Two common nonsynonymous SNPs did not demonstrate significant associations in either a family-based or case-control analysis. Exonic SNPs in the elastin gene do not appear to be common risk factors for severe COPD.

Topics: Adult; Aged; Case-Control Studies; Elastin; Emphysema; Exons; Female; Genetic Variation; Humans; Male; Middle Aged; Pedigree; Polymorphism, Genetic; Polymorphism, Single Nucleotide; Pulmonary Disease, Chronic Obstructive

Topics: Aged; Autoantibodies; Case-Control Studies; Cohort Studies; Elastin; Emphysema; Female; Humans; Male; Middle Aged; Pulmonary Fibrosis; Smoking

Matrix metalloproteinase (MMP)-9 has been consistently identified in the lungs of patients with chronic obstructive pulmonary disease (COPD). However, its role in the development of the disease remains undefined. Mice that specifically express human MMP-9 in their macrophages were generated, and morphometric, biochemical, and histological analyses were conducted on the transgenic and littermate control mice over 1 yr to determine the effect of macrophage MMP-9 expression on emphysema formation and lung matrix content. Lung morphometry was normal in transgenic mice at 2 mo of age (mean linear intercept = 50+/-3 littermate mice vs. 51+/-2 transgenic mice). However, after 12 mo of age, the MMP-9 transgenic mice developed significant air space enlargement (mean linear intercept = 53+/-3 littermate mice vs. 61+/-2 MMP-9 transgenic mice; P<0.04). Lung hydroxyproline content was not significantly different between wild-type and transgenic mice, but MMP-9 did significantly decrease alveolar wall elastin at 1 yr of age (4.9+/-0.3% area of alveolar wall in the littermate mice vs. 3.3+/-0.3% area of alveolar wall in the MMP-9 mice; P<0.004). Thus these results establish a central role for MMP-9 in the pathogenesis of this disease by demonstrating that expression of this protease in macrophages can alter the extracellular matrix and induce progressive air space enlargement in mice.

Topics: Animals; Elastin; Emphysema; Humans; Lung; Matrix Metalloproteinase 9; Mice; Mice, Transgenic; Pulmonary Alveoli; Pulmonary Disease, Chronic Obstructive

Chronic obstructive pulmonary disease and emphysema are common destructive inflammatory diseases that are leading causes of death worldwide. Here we show that emphysema is an autoimmune disease characterized by the presence of antielastin antibody and T-helper type 1 (T(H)1) responses, which correlate with emphysema severity. These findings link emphysema to adaptive immunity against a specific lung antigen and suggest the potential for autoimmune pathology of other elastin-rich tissues such as the arteries and skin of smokers.

Topics: Autoimmunity; B-Lymphocytes; Elastin; Emphysema; Humans; Lung; Pulmonary Disease, Chronic Obstructive; Smoking; T-Lymphocytes; T-Lymphocytes, Regulatory

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

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

Interstitial fibroblasts are an integral component of the alveolar wall. These cells produce matrix proteins that maintain the extracellular scaffold of alveolar structures. Emphysema is characterized by airspace enlargement resulting from the loss of alveolar cellularity and matrix. In this study, we explored the endotracheal delivery of fibroblasts to the lung parenchyma as a means of repairing damaged alveolar structures directly or indirectly for the delivery of transgenes. Fibroblasts were isolated from the lungs of neonatal transgenic mice expressing GFP during the period of rapid alveolarization. These GFP+ cells maintained their myofibroblast phenotype in culture and expressed elastin and alpha-smooth muscle actin mRNA. We administered GFP+ fibroblasts to saline- and elastase-treated mice by endotracheal instillation. We detected more GFP+ fibroblasts in the alveolar walls and in the interstitial areas of elastase-injured lungs than in normal lungs as assessed by immunohistochemistry and fluorescent imaging. The presence of GFP+ fibroblasts in the interstitium demonstrated transepithelial migration of these cells. Expression of GFP+ fibroblasts in recipient lungs was maintained for at least 20 d after endotracheal administration. These cells synthesize matrix components including elastin in vitro and could contribute to restoring the structural integrity of the alveolar wall.

Topics: Animals; Cells, Cultured; Elastin; Emphysema; Fibroblasts; Green Fluorescent Proteins; Humans; Lung; Mice; Mice, Inbred C57BL; Mice, Transgenic; Pancreatic Elastase

Mice with lung-specific expression of human matrix metalloproteinase-1 (MMP-1) develop emphysematous changes similar to those seen in smoking-induced emphysema in humans. Morphometric analyses of three transgenic lines [homozygous colony (Col) 34, Col 50, and Col 64] with varying temporal expression of MMP-1 were undertaken to determine the validity of this animal as a model of adult-onset emphysema. Line 50 mice, which have early expression of MMP-1 (14 days postconception), exhibited morphometric changes by 5 days of age. In contrast, homozygous line 34 and 64 with delayed expression (birth and 2 wk of age) were normal up until 4 wk of age when progressive changes in their mean linear intercept were first noted. In contrast, heterozygous mice from line 34 with lower transgene expression did not develop emphysema until 1 yr of age. The changes in mean linear intercept coincided with an increase in lung compliance. Emphysema in these mice was associated with decreased immunostaining for type III collagen within the alveolar septa. This study provides evidence that MMP-1 induces progressive adult-onset emphysema by the selective degradation of type III collagen within the alveolar wall.

Topics: Acute Disease; Age of Onset; Amino Acids; Animals; Bronchoalveolar Lavage Fluid; Collagen Type I; Collagen Type III; Elastin; Emphysema; Extracellular Matrix; Gene Expression Regulation, Enzymologic; Humans; Hydroxyproline; Immunohistochemistry; Leukocyte Count; Lung; Lung Compliance; Matrix Metalloproteinase 1; Mice; Mice, Inbred C57BL; Mice, Inbred CBA; Mice, Transgenic; Transgenes

Pulmonary emphysema is characterized by alveolar wall destruction and airspace enlargement. Recent evidence indicates that epithelial or endothelial apoptosis may be involved in the pathogenesis of emphysema. Here, we describe the induction of emphysematous changes, including airspace enlargement, alveolar wall destruction, and enhanced lung distensibility, in mice receiving a single intratracheal injection of active caspase-3 and Chariot, a newly developed protein transfection reagent. Epithelial apoptosis and enhanced elastolytic activity (optimal at pH 5.5) in bronchoalveolar lavage were noted. Emphysematous changes were also generated in mice receiving an intratracheal injection of nodularin, a proapoptotic serine/threonine kinase inhibitor. This murine model provides direct evidence that confirms that alveolar wall apoptosis causes emphysematous changes. Furthermore, this simple technique for protein transfection of lung tissue can be used in a variety of future applications.

Topics: Amino Acid Chloromethyl Ketones; Animals; Apoptosis; Bronchoalveolar Lavage Fluid; Caspase 3; Caspase Inhibitors; Caspases; Cells, Cultured; Cysteine Proteinase Inhibitors; Elastin; Emphysema; Humans; In Situ Nick-End Labeling; Male; Mice; Mice, Inbred C57BL; Pancreatic Elastase; Pulmonary Alveoli; Rats; Transfection

The cells/proteases responsible for the development of smoke-induced emphysema is an area of intense investigation. Mice with knockout of macrophage metalloelastase genes (MME(-/-)) do not develop emphysema after smoke exposure, but we also observed that neutrophils (PMN) in lavage appeared to be a requirement for acute connective tissue breakdown. In this study we exposed mice to cigarette smoke and examined lavage PMN, macrophages (MAC), desmosine (DES, a measure of elastin breakdown) and hydroxyproline (HP, a measure of collagen breakdown) 24 h afterwards. MME(+/+) mice exposed to smoke showed elevations in PMN, DES, and HP, but no elevations were seen in MME-deficient mice. Both PMN influx and increased levels of DES/HP could be restored by administering MAC from MME(+/+) mice to MME-deficient mice and then exposing them to smoke. RS113456, a metalloprotease inhibitor, also prevented PMN influx and connective tissue breakdown. Western blots against mouse alpha(1)-antitrypsin (alpha(1)AT) showed that alpha(1)AT was not protected in MME-deficient mice, nor by administration of RS113456. We conclude that, in mice, acute smoke-induced connective tissue breakdown, the precursor to emphysema, requires both PMN and MME, that PMN influx appears to be secondary to MAC activation, and that this process initially does not involve protection of alpha(1)AT from metalloprotease attack.

Topics: alpha 1-Antitrypsin; Animals; Bronchoalveolar Lavage Fluid; Cell Count; Collagen; Connective Tissue; Desmosine; Elastin; Emphysema; Enzyme Inhibitors; Hydroxyproline; Macrophages; Matrix Metalloproteinase 12; Metalloendopeptidases; Mice; Mice, Inbred C57BL; Mice, Knockout; Neutrophils; Pyrans; Tobacco Smoke Pollution

The elastic fibre system has a principal role in the structure and function of various types of organs that require elasticity, such as large arteries, lung and skin. Although elastic fibres are known to be composed of microfibril proteins (for example, fibrillins and latent transforming growth factor (TGF)-beta-binding proteins) and polymerized elastin, the mechanism of their assembly and development is not well understood. Here we report that fibulin-5 (also known as DANCE), a recently discovered integrin ligand, is an essential determinant of elastic fibre organization. fibulin-5-/- mice generated by gene targeting exhibit a severely disorganized elastic fibre system throughout the body. fibulin-5-/- mice survive to adulthood, but have a tortuous aorta with loss of compliance, severe emphysema, and loose skin (cutis laxa). These tissues contain fragmented elastin without an increase of elastase activity, indicating defective development of elastic fibres. Fibulin-5 interacts directly with elastic fibres in vitro, and serves as a ligand for cell surface integrins alphavbeta3, alphavbeta5 and alpha9beta1 through its amino-terminal domain. Thus, fibulin-5 may provide anchorage of elastic fibres to cells, thereby acting to stabilize and organize elastic fibres in the skin, lung and vasculature.

Topics: Animals; Aorta; Cells, Cultured; CHO Cells; Cricetinae; Cutis Laxa; Elastic Tissue; Elastin; Emphysema; Extracellular Matrix Proteins; Humans; Integrins; Lung; Mice; Mice, Inbred C57BL; Recombinant Proteins

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

Degradation of extracellular matrix components is central to many pathological features of chronic destructive lung disorders. Desmosine and isodesmosine are elastin-derived cross-linked amino acids whose urine levels are considered representative of elastin breakdown. The aim of this study was to apply a novel methodology, based on high-performance capillary electrophoresis, to the quantification of desmosine and isodesmosine in 11 patients with stable chronic obstructive pulmonary disease (COPD), 10 with an exacerbation of COPD, nine with alpha1-antitrypsin deficiency, 13 with bronchiectasis, and 11 adults with cystic fibrosis, in comparison to 24 controls. It was found that, in patients with stable COPD, urinary desmosine levels were higher than in controls (p=0.03), but lower than in COPD subjects with an exacerbation (p< or =0.05). The highest desmosine levels were found in subjects with alpha1-antitrypsin deficiency, bronchiectasis and cystic fibrosis (p<0.001 versus stable COPD). In a short-term longitudinal study, five stable COPD patients showed a constant rate of desmosine excretion (mean coefficient of variation <8% over three consecutive days). In conclusion, the present method is simple and suitable for the determination of elastin-derived cross-linked amino acid excretion in urine, giving results similar to those obtained using other separation methods. In addition, evidence is presented that urinary desmosine excretion is increased in conditions characterized by airway inflammation, such as exacerbations of chronic obstructive pulmonary disease, bronchiectasis and cystic fibrosis. Results obtained in subjects with alphal-antitrypsin deficiency suggest that this method might be used to evaluate the putative efficacy of replacement therapy.

Topics: Adult; Aged; Aged, 80 and over; alpha 1-Antitrypsin Deficiency; Bronchiectasis; Cross-Linking Reagents; Cross-Sectional Studies; Cystic Fibrosis; Desmosine; Elastin; Electrophoresis, Capillary; Emphysema; Extracellular Matrix; Female; Humans; Isodesmosine; Longitudinal Studies; Lung Diseases, Obstructive; Male; Middle Aged

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

The beige mouse is currently used as a model of elastase and cathepsin G deficiency to demonstrate or exclude the role of these proteases in a variety of pathologic conditions. We recently demonstrated that beige cathepsin G is tightly bound to neutrophil lysosomal membranes but is released in near normal quantities during exocytosis. Also, beige neutrophils contain a latent form of elastase that undergoes spontaneous activation when released under in vitro or in vivo conditions. However, the pathogenic potential of this enzyme in matrix degradation has not been ascertained previously. The possibility that in beige mice elastolytic proteases from neutrophils recruited into the lung have the capability to damage alveolar septa was investigated following an intratracheal instillation of N-formyl-L-methionyl-L-leucyl-L-phenylalanine (200 microg). Neutrophil influx was followed by a decrease in lung elastin content (-18%) and by a significant increase of the mean linear intercept (+30%) and of morphologic emphysema. The onset of pulmonary lesion was preceded by a marked increase of neutrophil elastase burden on the alveolar interstitium. The appearance of emphysema was prevented by administration of the serine protease inhibitor 4-(2-aminoetyl)-benzenesulfonyl fluoride hydrochloride (2. 4 microg/ml saline). These results demonstrate that the lung elastin degradation and emphysema can occur in beige lungs. The fact that the beige mouse does develop lung elastolytic changes after neutrophil recruitment indicates that this mutant cannot be considered a model of neutrophil function deficiency and used as a model of elastase deficiency.

Topics: Animals; Bronchoalveolar Lavage Fluid; Cell Movement; Elastin; Emphysema; Hydrolysis; Leukocyte Elastase; Lung; Male; Mice; Mice, Inbred C57BL; Neutrophils; Serine Proteinase Inhibitors

The aim of this study was to ascertain the putative roles of neutrophils or macrophages in the pathogenesis of cigarette smoking-induced emphysema on the basis of effects of anti-neutrophil (anti-PMN) antibody or anti-monocyte/macrophage (anti-MoMac) antibody on the development of emphysema in cigarette smoke-exposed rats. Rats were treated with rabbit anti-PMN or anti-MoMac antibody and exposed 7 days/wk for 2 mo to cigarette smoke inhalation; rats treated with nonimmunized rabbit IgG (control antibody) and exposed to cigarette smoke or normal room air served as controls. Antibody treatments began 24 h before the start of smoke or air exposure and was continued with 1 treatment/wk. Total and differential cell counts in bronchoalveolar lavage fluid and collagenase-dissociated lung and determinations of the elastinolytic activity of lung neutrophils or macrophages in [(3)H]elastin-coated wells indicated specific suppression of neutrophil accumulation and neutrophil-related elastinolytic burden in the lungs of the anti-PMN antibody-treated smoke-exposed rats, in contrast to specific suppression of macrophage accumulation and macrophage-related elastinolytic burden in the lungs of the anti-MoMac antibody-treated smoke-exposed rats. Cigarette smoke exposure-induced lung elastin breakdown (quantitated by immunologic assay of levels of elastin-derived peptides and desmosine in lavage fluid) and emphysema in the lungs (based on morphometric analysis of alveolar mean linear intercepts and alveolar tissue density in fixed lungs) were not prevented in the lungs of anti-PMN antibody-treated smoke-exposed rats but was clearly prevented in lungs of the anti-MoMac antibody-treated smoke-exposed rats. These findings implicate macrophages rather than neutrophils as the critical pathogenic factor in cigarette smoke-induced emphysema.

Topics: Animals; Antibodies; Bronchoalveolar Lavage Fluid; Elastin; Emphysema; Lung; Macrophages; Male; Neutrophils; Nicotiana; Plants, Toxic; Rats; Rats, Sprague-Dawley; Smoke

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 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

It is hypothesized that emphysema develops in some severely alpha 1-antitrypsin (AAT)-deficient persons because endogenous elastases are not adequately controlled by AAT, and accelerated elastin degradation occurs. It is not known whether augmentation therapy with AAT diminishes degradation of lung elastin in severely deficient persons with lung disease. Two severely deficient, PiZ patients were studied, a 63-year-old never-smoking woman with bronchiectasis and a 41-year-old smoking man with emphysema. Urinary desmosine (DES) was determined before and after augmentation therapy with AAT, 260 mg/kg/month. Mean +/- SEM pretreatment urinary DES was elevated in both patients, 19.7 +/- 0.9 (n = 2) and 10.8 +/- 0.2 (n = 2) micrograms/g creatinine, respectively, compared to normal values of 7.5 +/- 0.3 (n = 22) micrograms/g creatinine. Following augmentation therapy, urinary DES values decreased 40 and 36%, respectively, to 11.9 +/- 0.3 (n = 8) and 6.9 +/- 0.4 (n = 7) microgram/g creatinine (p < 0.05). We conclude that monthly AAT augmentation therapy decreased DES excretion in the urine of these PiZ patients. We speculate that since there was lung disease in both patients, a decrease in degradation of lung elastin is the most likely explanation for this observation.

Topics: Adult; alpha 1-Antitrypsin; alpha 1-Antitrypsin Deficiency; Amino Acids; Bronchiectasis; Desmosine; Elastin; Emphysema; Female; Humans; Isodesmosine; Lung; Male; Middle Aged; Smoking

We have previously shown that chronic cigarette smoke exposure produces emphysema and airflow obstruction in the guinea pig. To further examine the changes in the connective tissue matrix associated with emphysema in this model, we used ultrastructural morphometry to determine the volume proportions of collagen and elastin in the alveolar walls of animals exposed to smoke or air (control) for 1, 3, 6, and 12 mo. After 1 mo of smoke exposure, there was a statistically significant (P < 0.001) decrease in the volume proportion of collagen in the smoke-exposed animals, whereas by 6 and 12 mo of smoke exposure, the proportion of collagen had significantly (P < 0.02, P < 0.03, respectively) increased. The volume proportion of elastin was increased in the smoke-exposed animals at the 12-mo time period. While our results do not exclude reorganization of elastin within the alveolar wall, we conclude that, in this model, cigarette smoke-induced emphysema appears to be associated with collagen breakdown and repair. We suggest that the currently accepted proteolysis-antiproteolysis theory is too narrow in its focus on elastin destruction as the major contributor to emphysema and should be broadened to the concept that smoke-induced emphysema reflects breakdown and resynthesis (possibly overproduction in the form of scarring) of a variety of connective tissue proteins in addition to elastin.

Topics: Animals; Collagen; Elastin; Emphysema; Guinea Pigs; Microscopy, Electron; Nicotiana; Plants, Toxic; Pulmonary Alveoli; Smoke

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 determine whether human neutrophil cathepsin G can act by itself or in concert with human neutrophil elastase to destroy elastic fibers in vivo, we used cryostat sections of human skin as an ex vivo substrate for these leukoproteinases. Specifically stained dermal elastic fibers were quantitated using an accurate and almost entirely automatic morphometric procedure that included computerized threshold selection and elimination of non-elastic dark elements. AA, the area fraction occupied by the dermal elastic fibers, was found to be 0.100 +/- 0.014 (mean +/- SD) for 21 control skin sections originating from a single donor. Measurement of the fiber diameters in these control sections (2.4 +/- 0.8 microns [mean +/- SD]) allowed calculation of the Weibel factor used to convert AA into Vv, the volume fraction occupied by the elastic fibers: Vv was 0.028 +/- 0.004 (mean +/- SD). Incubation of skin sections with elastase, cathepsin G, or mixtures of the two enzymes resulted in an important decrease in AA accompanied by a slight increase in the average fiber diameter. The largest increase (14%) was noticed for cathepsin G and was due to a preferential attack of thin fibers and to fiber fragmentation. The AA of fibers remaining after elastolytic activity of cathepsin G was 20 to 30% that of elastase in this ex vivo assay. On the other hand, cathepsin G stimulated the elastolytic activity of elastase. For instance, the activity of a mixture of 1.1 microM elastase and 1.5 microM cathepsin G was 1.9-fold higher than the sum of the activities of the individual proteinases. The stimulation increased with the cathepsin G concentration.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Adult; Cathepsin G; Cathepsins; Elastin; Emphysema; Histocytochemistry; Humans; Image Processing, Computer-Assisted; Neutrophils; Pancreatic Elastase; Serine Endopeptidases; Skin; Solubility; Staining and Labeling

To study the pulmonary structural remodeling in pulmonary lymphangiomyomatosis, electron microscopy and light and electron microscopic immunohistochemical observations for elastin and alpha 1-antitrypsin were performed on five open lung biopsy samples. Lung specimens showed emphysema-like changes in areas of abnormally accumulated smooth muscle cells. In the alveolar walls having accumulated smooth muscle cells, elastic fibers were decreased in number, disrupted, granular, and occasionally accumulated. Ultrastructurally, elastic fibers in areas of smooth muscle cell accumulation showed poorly outlined amorphous components and a few microfibrils, and occasionally showed electron-dense granular deposits in and around the amorphous components. Spiraling collagen fibrils were frequently found associated with these abnormal elastic fibers. Immunohistochemistry for elastin showed even staining of amorphous components of elastic fibers in the areas of smooth muscle cell accumulation. alpha 1-Antitrypsin was also detected evenly in amorphous components of elastic fibers in the areas of smooth muscle cell accumulation. It is proposed that the emphysema-like lesions of lymphangiomyomatosis are mediated by the degradation of elastic fibers, and these degraded elastic fibers are related to an imbalance of the elastase/alpha 1-antitrypsin system similar to the probable pathogenesis of emphysema.

Topics: Adult; alpha 1-Antitrypsin; Elastic Tissue; Elastin; Emphysema; Female; Humans; Lung Neoplasms; Lymphangiomyoma; Middle Aged

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

Pulmonary elastic fibers in a patient with panacinar emphysema due to alpha-1-antitrypsin deficiency and three patients with centriacinar emphysema related to anthracosis were studied by electron microscopy and by light and electron microscopic immunohistochemistry for elastin. Four types of abnormal elastic fibers were found: (1) finely disrupted fibers, (2) fibers with vacuolar changes and deposits of electron-dense granular material, (3) accumulations of small, rounded amorphous components of elastic fibers near bundles of microfibrils, and (4) large, confluent masses consisting mainly of aggregates of irregularly and compactly arranged, small-sized amorphous components. The amorphous components in these four types of abnormal elastic fibers tended to stain evenly with antielastin antibody. This is attributed to greater penetration of antielastin antibody into fibers that were incompletely polymerized because of immaturity or hydrolytic damage. Finely disrupted fibers were frequently found in the patient with panacinar emphysema and were presumed to have been damaged by elastase. The other three types of elastic fibers were frequently found in the patients with centriacinar emphysema. The vacuoles and electron-dense deposits in elastic fibers probably represented the consequence of damage to elastic fibers. The small round amorphous components in elastic fibers might be formed from abnormal elastogenesis. The large, confluent elastic masses were thought to be formed by the aggregation of elastic fibers in areas of coalescence of alveolar walls undergoing structural remodeling.

Topics: Adult; Aged; alpha 1-Antitrypsin Deficiency; Elastic Tissue; Elastin; Emphysema; Humans; Immunoenzyme Techniques; Lung; Male; Microscopy, Electron; Middle Aged; Models, Biological

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

Topics: Elastin; Emphysema; Humans; Lung

Studies were designed to explore the possibility that human polymorphonuclear leukocyte granule constituents in addition to elastase (HLE) had the potential to cause emphysema. A two-step purification of three serine proteinases was developed. Granule extract proteins were initially separated by dye-ligand affinity chromatography. Fractions eluted were divided into four pools. Hamsters were given a single intratracheal instillation of saline +/- 0.1 mg protein of each pool. While pool 2 contained HLE and cathepsin G, the most dramatic bullous emphysema developed in animals treated with pool 4. The esterase from pool 4, designated proteinase 3 (PR-3) was purified, characterized in vitro, and tested for its ability to cause emphysema. PR-3 is a neutral serine proteinase with isoenzyme forms. Its ability to degrade elastin at pH 6.5 is slightly greater than that of HLE, but it is less active than HLE at pH 7.4 or 8.9. PR-3 has weak activity against azocasein. Its ability to degrade hemoglobin is intermediate to that of HLE and cathepsin G at pH 7.4. PR-3 has no activity against chromogenic substrates specific for HLE or cathepsin G. Its pI is substantially less than HLE or cathepsin G. It is also immunologically distinct from HLE. It induces emphysema in hamsters commensurate with that of HLE. We conclude that PR-3 may be important in the pathogenesis of human emphysema.

Topics: Animals; Cathepsin G; Cathepsins; Cricetinae; Elastin; Emphysema; Humans; Leukocyte Elastase; Myeloblastin; Naphthols; Neutrophils; Pancreatic Elastase; Serine Endopeptidases

To cause emphysema, proteases that are instilled into the air spaces must first be transported across the alveolar epithelium, a barrier that is normally quite impermeable to macromolecules. It was postulated that phospholipase A2 (PLA2) exposure would potentiate porcine pancreatic elastase (PPE)-induced epithelial solute permeability in a manner similar to that which was previously shown with lysophosphatidylcholine (lysoPC), a naturally occurring, membrane-perturbing agent that is formed principally through the hydrolysis of phosphatidylcholine by PLA2. Groups of hamsters were given intratracheal injections of PLA2 (0.3 units) or one of the expected hydrolytic products of PLA2 in equimolar concentrations, lysoPC (135 micrograms), arachidonic acid (AA) (100 micrograms), or palmitic acid (PA) (70 micrograms) with or without PPE (4 units). Epithelial permeability surface area products (PS) of the alveolar epithelium to [14C]sucrose and 125I-labeled neutral dextran (MW, 70,000) were measured in isolated perfused lungs 30 min after instillation, and emphysema severity was assessed at 3 wk by pressure-volume relationships and by mean linear intercepts. Additionally, the effects of lysoPC, PA, and AA on the functions of PPE and alpha 1-antiprotease (alpha 1 PI) in vitro were evaluated. Sucrose and dextran 70 PS differed significantly from controls only in those groups of hamsters that received PLA2 of lysoPC (p less than 0.05). LysoPC and PLA2 also potentiated the severity of PPE-induced emphysema to a similar degree (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: alpha 1-Antitrypsin; Animals; Blood Proteins; Cricetinae; Drug Interactions; Elastin; Emphysema; Epithelium; Female; Hydrolysis; Lysophosphatidylcholines; Mesocricetus; Pancreatic Elastase; Permeability; Phospholipases; Phospholipases A; Phospholipases A2; Pulmonary Alveoli; Swine

To determine whether lung elastin is lost during the evolution of cadmium-induced air-space enlargement with pulmonary fibrosis, the lung elastin of 5- to 7-day-old golden Syrian hamster pups was radiolabeled by giving [3H]valine. At maturity, a single intratracheal instillation of 0.5 ml of 0.025% CdCl2 solution was given. Lung mechanics, histologic examination, and biochemistry were studied 5, 10, 21, 42, 105, and 180 days after the cadmium treatment. The animals developed fibrosis and air-space enlargement with decreased lung volumes, compliance, and forced expiratory flow; their functional residual capacity was increased. The total lung collagen and total lung elastin were increased, but there was no loss of radiolabel in lung elastin. We conclude that CdCl2-induced air-space enlargement with pulmonary fibrosis is not accompanied by loss of neonatally formed lung elastic fibers. We hypothesize that air-space enlargement with fibrosis represents a stereotyped response of the lung to fibrosing injuries, which we hypothesize is due to forces from more fibrotic and atelectatic areas causing overdistension of less abnormal air spaces. The air-space enlargement of fibrosing human diseases such as sarcoidosis and eosinophilic granuloma may have a similar basis. Evidence is reviewed that human centrilobular emphysema may be a form of focal air-space enlargement with interstitial fibrosis; there may be mechanisms in addition to elastase-antielastase imbalance that cause human emphysema.

Topics: Animals; Cadmium; Cadmium Chloride; Elastin; Emphysema; Forced Expiratory Flow Rates; Humans; Lung; Organ Size; Pulmonary Fibrosis; Total Lung Capacity; Vital Capacity

We studied damage and repair of lung connective tissue in rats exposed to toxic amounts of oxygen by measuring lung content of collagen and elastin and the number of collagen fragments in lung lavage fluid after exposure to 98% O2 for 60 h. Lung collagen was decreased 17%, and collagen fragments in lavage fluid were increased 4- to 5-fold in O2-exposed rats compared with those in control rats. No biochemical evidence of elastin degradation was found. Mild emphysematous changes and a leftward shift of fluid-filled, pressure-volume curves were induced within 2 wk after recovery from exposure to O2. Administration of the lathyrogen beta-aminopropionitrile worsened the emphysematous lesion produced by hyperoxia, suggesting that replacement of connective tissue during repair limits the extent of emphysema. We conclude that lung collagen is degraded and an emphysematous lesion is produced by relatively short exposure to toxic amounts of oxygen.

Topics: Aging; Aminopropionitrile; Animals; Biomechanical Phenomena; Body Weight; Bronchi; Collagen; Connective Tissue; Elastin; Emphysema; Lung; Male; Oxygen; Proteins; Pulmonary Alveoli; Rats; Rats, Inbred Strains; Therapeutic Irrigation; Wound Healing

Topics: Cells, Cultured; Connective Tissue; Elastin; Emphysema; Humans; Lung Injury; Pulmonary Fibrosis

Topics: alpha 1-Antitrypsin; Animals; Bronchi; Cricetinae; Elastin; Emphysema; Epithelium; Humans; Lung; Microscopy, Electron; Nitrogen Dioxide; Pancreatic Elastase

Topics: Animals; Cathepsin G; Cathepsins; Cattle; Chymotrypsin; Elastin; Emphysema; Endopeptidases; Humans; Kinetics; Leukocytes; Lung; Pancreatic Elastase; Serine Endopeptidases; Substrate Specificity

Elastase-induced emphysema is associated with changes in all components of connective tissue, including elastin. The abnormal restructuring of lung parenchyma that occurs after elastase administration in hamsters might reflect an abnormal balance of elastin, collagen, and glycosaminoglycan in lung parenchyma. To test this hypothesis, we measured total amounts and levels of accumulation over 24 hr of connective tissue elements in lung explants at several points over a 1-year period after a single elastase treatment in hamsters. We found acute, early changes in the metabolism of elastin, collagen, and glycosaminoglycan consistent with degradation of elastin and increased turnover of collagen and glycosaminoglycan. By day 21 after elastase treatment, lung elastin had returned to control values, then rose and stayed elevated throughout the remainder of the study period. Total collagen levels rose in both control and elastase-treated lungs by the same amount over the year period. However, incorporation of 14C-proline into collagen hydroxyproline was elevated only in elastase-treated lungs over the period of 21 to 360 days. Incorporation of 14C-glucosamine into glycosaminoglycan was greatest over the period of 1 to 5 days after treatment and total levels also peaked at this time. By day 21 both incorporation of glucosamine and total levels of glycosaminoglycan had returned to normal, where they remained. The ratios of glycosaminoglycan to elastin and glycosaminoglycan to collagen were calculated over the period of 21 to 360 days to determine whether the long-term relative balance of these components had changed in elastase-treated lungs. We found that a steady-state imbalance existed between heparan sulfate and collagen and heparan sulfate and elastin, suggesting that an inappropriate amount of heparan sulfate was present relative to the amounts of collagen and elastin. We conclude that administration of elastase results in changes in the long-term balance of lung connective tissue components.

Topics: Animals; Collagen; Cricetinae; Elastin; Emphysema; Glycosaminoglycans; Hydroxyproline; Lung; Mesocricetus; Organ Culture Techniques; Pancreatic Elastase; Time Factors

Topics: Adult; Elastin; Emphysema; Enzyme Repression; Humans; Leukocytes; Metabolism, Inborn Errors; Pancreatic Elastase; Peptide Hydrolases; Trypsin Inhibitors; Ventilation-Perfusion Ratio

Topics: Adult; Age Factors; Aged; Aged, 80 and over; Aging; Amino Acids; Child; Chromatography, Gel; Collagen; Connective Tissue; Elastin; Emphysema; Female; Humans; Infant; Lung; Male; Middle Aged; Sex Factors

Topics: Collagen; Connective Tissue; Elastin; Emphysema; Humans; Lung; Pulmonary Emphysema