tretinoin and Hypertrophy

The terminally differentiated podocyte, also called glomerular visceral epithelial cell, are highly specialized cells. They function as a critical size and charge barrier to prevent proteinuria. Podocytes are injured in diabetic and non-diabetic renal diseases. The clinical signature of podocyte injury is proteinuria, with or without loss of renal function owing to glomerulosclerosis. There is an exciting and expanding literature showing that hereditary, congenital, or acquired abnormalities in the molecular anatomy of podocytes leads to proteinuria, and at times, glomerulosclerosis. The change in podocyte shape, called effacement, is not simply a passive process following injury, but is owing to a complex interplay of proteins that comprise the molecular anatomy of the different protein domains of podocytes. These will be discussed in this review. Recent studies have also highlighted that a reduction in podocyte number directly causes proteinuria and glomerulosclerosis. This is owing to several factors, including the relative inability for these cells to proliferate, detachment, and apoptosis. The mechanisms of these events are being elucidated, and are discussed in this review. It is the hope that by delineating the events following injury to podocytes, therapies might be developed to reduce the burden of proteinuric renal diseases.

Topics: Adrenal Cortex Hormones; Angiotensin II Type 1 Receptor Blockers; Apoptosis; Cell Adhesion; Cell Count; Cell Cycle; Cell Proliferation; Cytoskeleton; Diabetic Nephropathies; DNA Damage; Endothelium; Glomerular Basement Membrane; Glomerulosclerosis, Focal Segmental; Humans; Hypertrophy; Podocytes; Proteinuria; Tretinoin

Adult kidneys, which are principally composed of tubulointerstitium, do not normally regenerate or expand their working pool of functional cells at a very high rate. Loss of kidney tissue, however, can lead to some compensatory renal enlargement. The catalytic forces initiating such exchanges have not been fully articulated by current experimental endeavors. Increasing evidence, nevertheless, does suggest that factors other than simple changes in renal hemodynamics may be involved in this process. Different cellular elements in the tubulointerstitial microenvironment probably modulate changes in tubular enlargement or size through a complex cytokine network. Autocrine and paracrine stimulation of enlargement by different local growth factors also seem to play a pivotal role. After binding to cellular receptors, these factors activate signal transduction pathways resulting in expression of immediate early genes, which by themselves can synchronize the expression of subsequent genes through the medium of transacting factors. The renal enlargement response can also be modified by endocrine hormones that can activate such genes directly and/or stimulate other adjunctive processes, like receptor expression for the regional binding of growth factors. Furthermore, renal enlargement is under negative feedback of inhibitory factors like TGF beta. It is possible, for example, that special genes exist which are only expressed to arrest enlargement. It has been further suggested that activation of the Na+/H+ antiporter is a common denominator in renal enlargement. Recent findings, however, indicate that the activation of this antiporter is not always necessary, and might rather be a parallel event rather than a key phenomena in tubular enlargement. G0/G1 transition of tubular cells seems to involve similar factors in tubular hypertrophy and hyperplasia. The factors which are responsible for the final determination of the enlargement pattern (hypertrophy vs. proliferation) are unknown. The separation between hypertrophy and hyperplasia, although suggested by striking differences in cellular regulation, may be somewhat artificial, since responses leading to tubular enlargement also exist in circumstances where hyperplasia and hypertrophy are combined events. Recently it has been proposed that growth factors stimulate gluconeogenesis in proximal tubular cells producing hyperplasia, whereas factors inhibiting gluconeogenesis might induce hypertrophy. Whether the common p

Topics: Animals; Carrier Proteins; Cell Cycle; Gene Expression; Growth Substances; Humans; Hydrogen-Ion Concentration; Hyperplasia; Hypertrophy; Kidney; Kidney Tubules; Proto-Oncogenes; Signal Transduction; Sodium-Hydrogen Exchangers; Steroids; Tretinoin

In recent years there has been a growing awareness that many of the so-called attributes of aging skin are, instead, a reflection of environmental assault upon exposed areas of the body. Of special import are the deleterious effects of solar radiation on dermal connective tissue, leading to the visible manifestations of photoaging. Often termed "premature aging," the salient features of the process are distinctly different from those found in normal intrinsic aging. In general, chronically irradiated skin is metabolically hyperactive with epidermal hyperplasia and neoplasia, increased production of elastic fibers, GAGs, accelerated breakdown and synthesis of collagen, and enhanced inflammatory processes. In contrast, protected aged skin is usually characterized by a slow decline in many of these components. Experimental studies with animal models have confirmed the notion that the shorter, more energetic portion of the ultraviolet spectrum (UVB) is responsible for the dermal connective tissue destruction observed in photoaged skin. More recently, it has been shown that UVA and infrared radiation contribute significantly to photoaging, producing, among other changes, severe elastosis. Because the three broad wavebands are inseparably linked in terrestrial sunlight, all are of concern in the photoaging of human skin. Photoaged skin has been thought to be irreversibly damaged. However, our findings indicate that destruction and repair go on simultaneously under continued assault by actinic radiation. The balance is shifted toward repair when the radiation stress is relieved. Both epidermis and dermis are capable of moderate self-restoration when exogenous injury ceases, either by avoidance of sunlight or by the use of broad-spectrum, high-SPF sunscreens. Repair of the dermis, characterized by broad regions of new collagen deposited subepidermally, can be pharmacologically enhanced by topical application of retinoic acid. Although early protection from sunlight, before severe photodamage occurs, is most desirable, it is deemed advisable to counsel even older persons with photoaged skin to adopt protective measures, thereby allowing repair processes to occur.

Topics: Aging; Animals; Atrophy; Dose-Response Relationship, Radiation; Drug Evaluation, Preclinical; Elastic Tissue; Guinea Pigs; Humans; Hypertrophy; Infrared Rays; Mice; Skin; Sunlight; Sunscreening Agents; Tretinoin; Ultraviolet Rays

The regulation of adipose deposition in broiler chickens is an important factor for production efficiency to poultry producers and health concerns to customers. Although vitamin A and its metabolite [all-trans retinoic acid (atRA)] have been used for studies on adipogenesis in mammals and avian, effects of embryonic atRA on adipose development in embryonic (E) and posthatch (D) ages in broiler chickens have not been studied yet. Different concentrations of atRA (0 M-2 μM) were injected in broiler eggs at E10, and adipose tissues were sampled at E16. Percentages of adipose tissues in chicken embryos were significantly increased in the group injected with 500 nM of atRA compared to the 0 M group (P < 0.05). In addition, the adipocyte cross-sectional area (CSA) was significantly greater by in ovo injection of 500 nM atRA compared to the injection of 0 M (P < 0.01). Moreover, in ovo atRA-injected embryos were hatched and BWs were measured at D0, D7, and D14. BWs were not different from those of the 0 M group. Percentages of adipose tissues and CSA of the in ovo atRA-injected group (500 nM) were not different from those of the 0 M group at D14. Taken together, the current study clearly showed that in ovo injection of atRA promoted adipose deposition with hypertrophy during embryonic development, but its effects were not maintained in early posthatch age in broiler chickens, implying that embryonic atRA has an important role in the regulation of adipose development in chicken embryos.

Topics: Adipocytes; Animals; Chick Embryo; Chickens; Hypertrophy; Mammals; Ovum; Tretinoin

Airway smooth muscle (ASM) is a dynamic and complex tissue involved in regulation of bronchomotor tone, but the molecular events essential for the maintenance of ASM homeostasis are not well understood. Observational and genome-wide association studies in humans have linked airway function to the nutritional status of vitamin A and its bioactive metabolite retinoic acid (RA). Here, we provide evidence that ongoing RA signaling is critical for the regulation of adult ASM phenotype. By using dietary, pharmacologic, and genetic models in mice and humans, we show that (a) RA signaling is active in adult ASM in the normal lung, (b) RA-deficient ASM cells are hypertrophic, hypercontractile, profibrotic, but not hyperproliferative, (c) TGF-β signaling, known to cause ASM hypertrophy and airway fibrosis in human obstructive lung diseases, is hyperactivated in RA-deficient ASM, (d) pharmacologic and genetic inhibition of the TGF-β activity in ASM prevents the development of the aberrant phenotype induced by RA deficiency, and (e) the consequences of transient RA deficiency in ASM are long-lasting. These results indicate that RA signaling actively maintains adult ASM homeostasis, and disruption of RA signaling leads to aberrant ASM phenotypes similar to those seen in human chronic airway diseases such as asthma.

Topics: Adult; Animals; Benzoates; Cells, Cultured; Disease Models, Animal; Female; Fibrosis; Humans; Hypertrophy; Lung; Lung Diseases, Obstructive; Male; Mice; Mice, Transgenic; Muscle, Smooth; Myocytes, Smooth Muscle; Primary Cell Culture; Receptors, Retinoic Acid; Signal Transduction; Stilbenes; Tretinoin

The objective of the present study was to examine the genetically determined differences in the natriuretic peptide receptor-A (NPRA) gene (Npr1) copies affecting the expression of cardiac hypertrophic markers, proinflammatory mediators, and matrix metalloproteinases (MMPs) in a gene-dose-dependent manner. We determined whether stimulation of Npr1 by all-trans retinoic acid (RA) and histone deacetylase (HDAC) inhibitor sodium butyric acid (SB) suppress the expression of cardiac disease markers. In the present study, we utilized Npr1 gene-disrupted heterozygous (Npr1(+/-), 1-copy), wild-type (Npr1(+/+), 2-copy), gene-duplicated (Npr1(++/+), 3-copy) mice, which were treated intraperitoneally with RA, SB, and a combination of RA/SB, a hybrid drug (HB) for 2 wk. Untreated 1-copy mice showed significantly increased heart weight-body weight (HW/BW) ratio, blood pressure, hypertrophic markers, including beta-myosin heavy chain (β-MHC) and proto-oncogenes (c-fos and c-jun), proinflammatory mediator nuclear factor kappa B (NF-κB), and MMPs (MMP-2, MMP-9) compared with 2-copy and 3-copy mice. The heterozygous (haplotype) 1-copy mice treated with RA, SB, or HB, exhibited significant reduction in the expression of β-MHC, c-fos, c-jun, NF-κB, MMP-2, and MMP-9. In drug-treated animals, the activity and expression levels of HDAC were significantly reduced and histone acetyltransferase activity and expression levels were increased. The drug treatments significantly increased the fractional shortening and reduced the systolic and diastolic parameters of the Npr1(+/-) mice hearts. Together, the present results demonstrate that a decreased Npr1 copy number enhanced the expression of hypertrophic markers, proinflammatory mediators, and MMPs, whereas an increased Npr1 repressed the cardiac disease markers in a gene-dose-dependent manner.

Topics: Animals; Biomarkers; Blood Pressure; Butyric Acid; Cytokines; Diastole; Haplotypes; Heart; Hypertrophy; Inflammation; Male; Mice; Receptors, Atrial Natriuretic Factor; Systole; Tretinoin

The mouse aldehyde oxidase AOH2 (aldehyde oxidase homolog 2) is a molybdoflavoenzyme. Harderian glands are the richest source of AOH2, although the protein is detectable also in sebaceous glands, epidermis, and other keratinized epithelia. The levels of AOH2 in the Harderian gland and skin are controlled by genetic background, being maximal in CD1 and C57BL/6 and minimal in DBA/2, CBA, and 129/Sv strains. Testosterone is a negative regulator of AOH2 in Harderian glands. Purified AOH2 oxidizes retinaldehyde into retinoic acid, while it is devoid of pyridoxal-oxidizing activity. Aoh2(-/-) mice, the first aldehyde oxidase knockout animals ever generated, are viable and fertile. The data obtained for this knockout model indicate a significant role of AOH2 in the local synthesis and biodisposition of endogenous retinoids in the Harderian gland and skin. The Harderian gland's transcriptome of knockout mice demonstrates overall downregulation of direct retinoid-dependent genes as well as perturbations in pathways controlling lipid homeostasis and cellular secretion, particularly in sexually immature animals. The skin of knockout mice is characterized by thickening of the epidermis in basal conditions and after UV light exposure. This has correlates in the corresponding transcriptome, which shows enrichment and overall upregulation of genes involved in hypertrophic responses.

Topics: Aging; Aldehyde Oxidoreductases; Animals; Endocytosis; Epidermis; Exocytosis; Female; Flavoproteins; Gene Expression Profiling; Gene Expression Regulation; Harderian Gland; Hypertrophy; Lipids; Male; Mice; Mice, Inbred Strains; Mice, Knockout; Oligonucleotide Array Sequence Analysis; Retinaldehyde; Sebaceous Glands; Sex Characteristics; Testosterone; Tretinoin

Retinoids are important for growth plate chondrocyte maturation, but their downstream effectors remain unclear. Recently, CTGF (CCN2) was found to regulate chondrocyte function, particularly in the hypertrophic zone. The goal of the study was to determine whether CTGF is a retinoid signaling effector molecule, how it is regulated, and how it acts.. Using a combination of in vivo and in vitro approaches, we carried out a series of studies at the cellular, biochemical, and molecular level to determine whether and how retinoid signaling is related to expression and function of connective tissue growth factor (CTGF) in chondrocyte maturation and endochondral ossification.. Limbs of chick embryos in ovo were implanted with retinoic pan-antagonist RO 41-5253-filled beads, and phenotypic changes were assessed by in situ hybridization. CTGF gene expression and roles were tested in primary cultures of immature and hypertrophic chondrocytes. Cross-talk between retinoid signaling and other pathways was tested by determining endogenous levels of active ERK1/2 and p38 MAP kinases and phenotypic modulations exerted by specific antagonists of mitogen-activated protein (MAP) kinases and BMP signaling (Noggin).. Interference with retinoid signaling blocked expression of CTGF and other posthypertrophic markers in long bone anlagen in vivo and hypertrophic chondrocyte cultures, whereas all-trans-retinoic acid (RA) boosted CTGF expression and even induced it in immature proliferating cultures. Exogenous recombinant CTGF stimulated chondrocyte maturation, but failed to do so in presence of retinoid antagonists. Immunoblots showed that hypertrophic chondrocytes contained sizable levels of phosphorylated ERK1/2 and p38 MAP kinases that were dose- and time-dependently increased by RA treatment. Experimental ERK1/2 inhibition led to a severe drop in baseline and RA-stimulated CTGF expression, whereas p38 inhibition increased it markedly. These responses were gene-specific, because the opposite was seen with other hypertrophic chondrocyte genes such as collagen X and RA receptor gamma (RARgamma). Tests with Noggin showed that RA induction of CTGF expression was negatively influenced by BMP signaling, whereas induction of collagen X expression was BMP-dependent.. Retinoids appear to have a preeminent role in controlling expression and function of CTGF in hypertrophic and posthypertrophic chondrocytes and do so with differential cooperation and intervention of MAP kinases and BMP signaling.

Topics: Animals; Blotting, Northern; Chick Embryo; Chondrocytes; Connective Tissue Growth Factor; Dose-Response Relationship, Drug; Gene Expression Regulation; Hypertrophy; Immediate-Early Proteins; Immunoblotting; In Situ Hybridization; Intercellular Signaling Peptides and Proteins; MAP Kinase Signaling System; Mitogen-Activated Protein Kinase 1; Mitogen-Activated Protein Kinase 3; Models, Biological; p38 Mitogen-Activated Protein Kinases; Phenotype; Protein Binding; Retinoids; Signal Transduction; Time Factors; Tretinoin

Altered chondrocyte differentiation, including development of chondrocyte hypertrophy, mediates osteoarthritis and pathologic articular cartilage matrix calcification. Similar changes in endochondral chondrocyte differentiation are essential for physiologic growth plate mineralization. In both articular and growth plate cartilages, chondrocyte hypertrophy is associated with up-regulated expression of certain protein-crosslinking enzymes (transglutaminases (TGs)) including the unique dual-functioning TG and GTPase TG2. Here, we tested if TG2 directly mediates the development of chondrocyte hypertrophic differentiation. To do so, we employed normal bovine chondrocytes and mouse knee chondrocytes from recently described TG2 knockout mice, which are phenotypically normal. We treated chondrocytes with the osteoarthritis mediator IL-1 beta, with the all-trans form of retinoic acid (ATRA), which promotes endochondral chondrocyte hypertrophy and pathologic calcification, and with C-type natriuretic peptide, an essential factor in endochondral development. IL-1 beta and ATRA induced TG transamidation activity and calcification in wild-type but not in TG2 (-/-) mouse knee chondrocytes. In addition, ATRA induced multiple features of hypertrophic differentiation (including type X collagen, alkaline phosphatase, and MMP-13), and these effects required TG2. Significantly, TG2 (-/-) chondrocytes lost the capacity for ATRA-induced expression of Cbfa1, a transcription factor necessary for ATRA-induced chondrocyte hypertrophy. Finally, C-type natriuretic peptide, which did not modulate TG activity, comparably promoted Cbfa1 expression and hypertrophy (without associated calcification) in TG2 (+/+) and TG2 (-/-) chondrocytes. Thus, distinct TG2-independent and TG2-dependent mechanisms promote Cbfa1 expression, articular chondrocyte hypertrophy, and calcification. TG2 is a potential site for intervention in pathologic calcification promoted by IL-1 beta and ATRA.

Topics: Alkaline Phosphatase; Animals; Calcinosis; Cartilage, Articular; Cattle; Cells, Cultured; Chondrocytes; Collagen Type X; Collagenases; Core Binding Factor Alpha 1 Subunit; Extremities; Gene Expression; GTP-Binding Proteins; Hypertrophy; Interleukin-1; Matrix Metalloproteinase 13; Mice; Mice, Inbred C57BL; Mice, Knockout; Natriuretic Peptide, C-Type; Neoplasm Proteins; Osteoarthritis; Protein Glutamine gamma Glutamyltransferase 2; Transcription Factors; Transglutaminases; Tretinoin

There are in vitro data linking all-trans retinoic acid (atRA) with inhibition of hypertrophy and hyperplasia in cardiomyocytes, vascular smooth muscle cells, and fibroblasts. In the present study, we tested the hypothesis that chronic treatment with atRA may blunt the process of myocardial remodeling in spontaneously hypertensive rats (SHR). Four-week-old male SHR were treated with atRA (5 or 10 mg.kg-1.day-1) given daily for 3 mo by gavage; age- and sex-matched Wistar-Kyoto rats (WKY) and placebo-treated SHR served as controls. At the end of the treatment period, cardiac geometry and function were assessed by Doppler echocardiography. Histological examination and RIA were performed to evaluate medial thickening of intramyocardial and renal arteries, perivascular and interstitial collagen content, and atrial natriuretic peptide (ANP) and IGF-I in the heart, respectively. The novel finding of the present study is that atRA prevented hypertrophy of intramyocardial and intrarenal arteries and ventricular fibrosis. However, atRA treatment did not lower blood pressure or left ventricular weight and left ventricular weight-to-body weight ratio in SHR. atRA did not change cardiac geometry and function as assessed by Doppler echocardiography. atRA showed no influence on either ANP or IGF-I levels. In conclusion, the present study suggests that chronic atRA treatment prevents medial thickening of intramyocardial and intrarenal arteries and ventricular fibrosis during the development of hypertension. Left ventricular hypertrophy and cardiac geometry and function are not changed by atRA treatment.

Topics: Animals; Body Weight; Coronary Vessels; Drug Administration Schedule; Fibrosis; Heart; Heart Ventricles; Hemodynamics; Hypertension; Hypertrophy; Male; Myocardium; Organ Size; Rats; Rats, Inbred SHR; Rats, Inbred WKY; Renal Artery; Tretinoin; Tunica Media

The relationship between interscapular brown adipose tissue (IBAT) thermogenic potential and vitamin A status was investigated by studying the effects of feeding a vitamin A-deficient diet and all-trans retinoic acid (tRA) treatment on body weight and IBAT parameters in mice. Feeding a vitamin A-deficient diet tended to trigger opposite effects to those of tRA treatment, namely increased body weight, IBAT weight, adiposity and leptin mRNA expression, and reduced IBAT thermogenic potential in terms of uncoupling protein 1 (UCP1) mRNA and UCP2 mRNA expression. The results emphasize the importance of retinoids as physiological regulators of brown adipose tissue.

Topics: Adipose Tissue, Brown; Animals; Blotting, Northern; Body Temperature Regulation; Body Weight; Carrier Proteins; Hypertrophy; Ion Channels; Leptin; Male; Membrane Proteins; Membrane Transport Proteins; Mice; Mice, Inbred Strains; Mitochondrial Proteins; Proteins; RNA, Messenger; Tretinoin; Uncoupling Protein 1; Uncoupling Protein 2; Vitamin A Deficiency

Numerous studies of experimental hypo- and hypervitaminosis A have long suggested that retinoic acid (RA) is involved in chondrocyte maturation during endochondral ossification and skeletogenesis. However, the specific and direct roles of RA in these complex processes remain unclear. Based on recent studies from our laboratories, we tested the hypothesis that RA induces the expression of genes associated with the terminal mineralization phase of chondrocyte maturation and promotes apatite deposition in the extracellular matrix. Cell populations containing chondrocytes at advanced stages of maturation were isolated from the upper portion of Day 18 chick embryo sterna and grown for 2 weeks in monolayer until confluent. The cells were then treated with low doses (10-100 nM) of RA for up to 6 days in the presence of a phosphate donor (beta-glycerophosphate) but in the absence of ascorbic acid. Within 4 days of treatment, RA dramatically induced expression of the alkaline phosphatase (APase), osteonectin, and osteopontin genes, caused a several-fold increase in APase activity, and provoked massive mineral formation while it left type X collagen gene expression largely unchanged. The mineral had a mean Ca/Pi molar ratio of 1.5; Fourier transform infrared spectra confirmed that it represented hydroxyapatite. Mineralization was completely abolished by treatment with parathyroid hormone; this profound effect confirmed that RA induced cell-mediated mineralization and not nonspecific precipitation. When cultures were treated with both RA and ascorbic acid, there was a slight further increase in APase activity and increased calcium accumulation. The effects of RA were also studied in cultures of immature chondrocytes isolated from the caudal portion of sternum; however, RA only had minimal effects on mineralization and gene expression in these cells. Thus, RA appears to be a rapid, potent, maturation-dependent, ascorbate-independent promoter of terminal maturation and matrix calcification in chondrocytes.

Topics: Alkaline Phosphatase; Animals; Apatites; Ascorbic Acid; Calcification, Physiologic; Calcium; Cartilage; Cells, Cultured; Chick Embryo; Collagen; Dose-Response Relationship, Drug; Extracellular Matrix; Fluorescent Antibody Technique; Gene Expression; Hypertrophy; Minerals; Osteonectin; Osteopontin; Parathyroid Hormone; Sialoglycoproteins; Time Factors; Tretinoin

We present a case of hypertrophic lupus erythematosus treated with topical tretinoin. To date, we believe this is the first description of such treatment of this disease.

Topics: Acute Disease; Administration, Cutaneous; Adult; Female; Humans; Hypertrophy; Lupus Erythematosus, Cutaneous; Skin; Sunscreening Agents; Tretinoin

Topics: Acne Vulgaris; Adolescent; Granulation Tissue; Humans; Hypertrophy; Isotretinoin; Male; Tretinoin

Topics: Animals; DNA; Epidermis; Female; Hyperplasia; Hypertrophy; Mice; Skin; Time Factors; Tretinoin; Ultraviolet Rays

After treatment of pachydermias of the larynx with aromatic retinoid (Hoffmann-La Roche, Basel, Switzerland), an increased number of large vacuoles interpreted as cytolysosomes in cells predominantly of the stratum basale and spinosum is found. In the superficial cell layers an enhanced number of necrotic cells can be detected. It is assumed that retinoids lead to a cell damage and a stimulation of the lysosomal system.

Topics: Epithelium; Etretinate; Humans; Hypertrophy; Laryngeal Mucosa; Larynx; Necrosis; Tretinoin; Vocal Cords

In a clinical trial twenty-eight intractable cases with scars were treated with daily applications of a 0.05% solution of retinoic acid. The results were evaluated objectively and subjectively. Slight to marked reduction of the size of these scars and decrease of such complaints as itching were noted in the majority of the cases. A favourable result was obtained according to the patients in 79%, and according to the opinion of the medical examiner in 77% of the patients.

Topics: Administration, Topical; Adolescent; Adult; Aged; Child; Child, Preschool; Cicatrix; Female; Humans; Hypertrophy; Keloid; Male; Middle Aged; Tretinoin

Topics: Cicatrix; Female; Humans; Hypertrophy; Time Factors; Tretinoin