elastin and Cardiomyopathies

Lysosomal carboxypeptidases play important roles in catabolism of proteins and peptides and in posttranslational processing of other lysosomal enzymes. The major lysosomal serine carboxypeptidase A (cathepsin A [CathA]), also known as protective protein, activates and stabilizes two other lysosomal enzymes, beta-galactosidase and neuraminidase/sialidase 1. Genetic deficiency of CathA (galactosialidosis) causes the lysosomal storage of sialylated glycoconjugates and leads to a multiorgan pathology. The galactosialidosis patients also show arterial hypertension and cardiomyopathy, conditions not predicted from the lysosomal storage of glycoconjugates. This review summarizes the experimental data suggesting that both cardiovascular pathologies associate with persisted vasoconstrictions and impaired formation of the elastic fibers triggered by the deficiency of CathA. We also discuss the homologous serine carboxypeptidases, Scpep1 and vitellogenic-like carboxypeptidase, that are secreted from endothelial cells and could potentially affect the cardiovascular system.

Topics: beta-Galactosidase; Carboxypeptidases; Carboxypeptidases A; Cardiomyopathies; Elastic Tissue; Elastin; Enzyme Activation; Glycoconjugates; Humans; Hypertension; Lysosomal Storage Diseases; Neuraminidase; Vasoconstriction

Biodegradable polyurethane patches have been applied as temporary mechanical supports to positively alter the remodeling and functional loss following myocardial infarction. How long such materials need to remain in place is unclear. Our objective was to compare the efficacy of porous onlay support patches made from one of three types of biodegradable polyurethane with relatively fast (poly(ester urethane)urea; PEUU), moderate (poly(ester carbonate urethane)urea; PECUU), and slow (poly(carbonate urethane)urea; PCUU) degradation rates in a rat model of ischemic cardiomyopathy. Microporous PEUU, PECUU or PCUU (n = 10 each) patches were implanted over left ventricular lesions 2 wk following myocardial infarction in rat hearts. Infarcted rats without patching and age-matched healthy rats (n = 10 each) were controls. Echocardiography was performed every 4 wk up to 16 wk, at which time hemodynamic and histological assessments were performed. The end-diastolic area for the PEUU group at 12 and 16 wk was significantly larger than for the PECUU or PCUU groups. Histological analysis demonstrated greater vascular density in the infarct region for the PECUU or PCUU versus PEUU group at 16 wk. Improved left ventricular contractility and diastolic performance in the PECUU group was observed at 16 wk compared to infarction controls. The results indicate that the degradation rate of an applied elastic patch influences the functional benefits associated patch placement, with a moderately slow degrading PECUU patch providing improved outcomes.

Topics: Animals; Biocompatible Materials; Cardiomyopathies; Catheterization; Collagen; Elasticity; Elastin; Female; Heart Ventricles; Hemodynamics; Macrophages; Magnetic Resonance Imaging; Materials Testing; Microscopy, Electron, Scanning; Myocardial Infarction; Myocardial Ischemia; Polyurethanes; Prosthesis Implantation; Rats; Rats, Inbred Lew; Time Factors; Tissue Scaffolds; Ultrasonography

This study aimed to investigate the effect of decellularization plus photooxidative crosslinking and ethanol pretreatment on bioprosthetic tissue calcification. Photooxidatively crosslinked acellular (PCA) bovine jugular vein conduits (BJVCs) and their photooxidized controls (n = 5 each) were sterilized in a graded concentration of ethanol solutions for 4 h, and used to reconstruct dog right ventricular outflow tracts. At 1-year implantation, echocardiography showed similar hemodynamic performance, but obvious calcification for the photooxidized BJVC walls. Further histological examination showed intense calcium deposition colocalized with slightly degraded elastic fibers in the photooxidized BJVC walls, with sparsely distributed punctate calcification in the valves and other areas of walls. But PCA BJVCs had apparent degradation of elastic fibers in the walls, with only sparsely distributed punctate calcification in the walls and valves. Content assay demonstrated comparable calcium content for the two groups at preimplantation, whereas less calcium for the PCA group in the walls and similar calcium in the valvular leaflets compared with the photooxidized group at 1-year retrieval. Elastin content assay presented the conduit walls of PCA group had less elastin content at preimplantation, but similar content at 1-year retrieval compared with the photooxidized group. Phospholipid analysis showed phospholipid extraction by ethanol for the PCA group was more efficacious than the photooxidized group. These results indicate that PCA BJVCs resist calcification in right-side heart implantation owing to decellularization, further photooxidative crosslinking, and subsequent phospholipid extraction by ethanol at preimplantation.

Topics: Animals; Calcinosis; Calcium; Cardiomyopathies; Cattle; Cross-Linking Reagents; Dogs; Elastin; Heart Valve Prosthesis; Heart Valves; Heart Ventricles; Immunohistochemistry; Jugular Veins; Light; Oxidation-Reduction; Phospholipids; Prosthesis Implantation; Staining and Labeling; Ultrasonography

In many remodeling tissues, such as the heart, collagen degradation to provide new integrin-binding sites is required for survival. However, complete loss of integrin signaling due to disconnection from extracellular matrix (ECM) leads to apoptosis and dilatation. To test the hypothesis that a mutation in type I collagen gene induces cardiomyopathy, we employed a metalloproteinase-resistant collagen mutant homozygous transgenic male (B6,129-Colla-1) and compared with age-sex matched wildtype C57BL/J6 control mice. At the age of 38-42 weeks, aortic and left ventricle (LV) pressure were measured. The LV wall thickness and diameter were measured by a digital micrometer. The levels of matrix metalloproteinase-2 (MMP-2) activity and cardiospecific tissue inhibitor of metalloproteinase-4 (TIMP-4) were measured by zymography and Western blot analyses, respectively. The levels of collagenolysis were measured by Western blot using anti-collagen antibody. In transgenic and wildtype mice, end-diastolic pressure (EDP) was 8.3 +/- 1.7 and 6.5 +/- 1.1 mmHg; LV diameter was 3.43 +/- 0.07 and 2.94 +/- 0.05 mm; wall thickness was 1.18 +/- 0.03 and 1.28 +/- 0.04 mm; end-diastolic wall stress was 600 +/- 158 and 347 +/- 49 dynes/cm(2), respectively. The increase in LV wall stress was associated with increased MMP-2 activity, increased collagenolysis, and decreased levels of TIMP-4. This leads to reduced elastic compliance in collagen mutant transgenic mice. The occurrence of cardiomyopathy in adult Colla-1 mice may be a significant confounding factor as it may be indicative of increased basal levels of ECM disruption. This phenotype is what would be expected if collagen degradation normally supplies integrin ligands during cardiac muscle remodeling.

Topics: Animals; Cardiomyopathies; Collagen; Elastin; Electrocardiography; Female; Heart Injuries; Male; Matrix Metalloproteinase 2; Mice; Mice, Inbred C57BL; Mice, Transgenic; Mutation; Norepinephrine; Tissue Inhibitor of Metalloproteinases; Ventricular Function, Left

Cardiomyopathy was produced by isoprenaline injections to healthy and hydrazinophthalazine-treated rats. The elastin content in the heart muscle and the aortic wall as well as the level of serum elastolytic activity were determined. An increase of elastin content in both tissues was found, and its progress was concomitant with the development of isoprenaline injury. It was also found that the elastolytic activity increased on the second day after the last isoprenaline injection, and on the seventh day of the experiment it began to decrease. Changes in hydrazinophthalazine-treated rats after dosing them with isoprenaline had a similar tendency but they were significantly lower than those found in healthy animals receiving isoprenaline only.

Topics: Animals; Cardiomyopathies; Collagen Diseases; Elastin; Hydralazine; Isoproterenol; Male; Pancreatic Elastase; Rats; Rats, Inbred Strains

Two groups of human pathological papillary muscle samples were analyzed by 1H-NMR spectroscopy and histology. The first group, mainly characterized by hypertrophy of the myocardial cells, interstitial edema and intracellular lipoperoxide accumulation showed similar T1 as well as T2 values. The second group, mainly characterized by hypertrophy of the myocardial cells, fibrosis and areas of necrosis showed T1 values longer than those of the first group while no appreciable differences were evident in the T2 values. These results suggest that a certain degree of correlation exists between the histologic features of the cardiac tissue examined and the relaxation behavior as defined by nuclear magnetic resonance spectroscopy even if a definite association between them is still not possible.

Topics: Cardiomyopathies; Cardiomyopathy, Hypertrophic; Child, Preschool; Collagen; Elastin; Female; Humans; Magnetic Resonance Spectroscopy; Male; Middle Aged; Papillary Muscles