Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.24.3 (collagenase)
 18,340 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Right ventricular cardiac tissue (10-20 mg wet weight) was obtained from anesthetized adult dogs by endomyocardial biopsy. The biopsy could be repeated in one dog every 2 weeks for up to 3 months. Fifty to 200 cardiomyocytes, dispersed with collagenase and trypsin, were collected by centrifugation of the cells with 50% polysucrose-sodium diatrizoate solution (Ficoll-Paque). Single cardiomyocytes were suspended in a minimum essential medium containing 20% fetal bovine serum and 8-bromoadenosine 3': 5'-cyclic monophosphate (0.1 mM) for up to 3 weeks. Approximately 70-80% of the cultured cardiomyocytes were rod shaped after 24 hours (10-20% after 7 days). Cytoplasmic organelles of the cultured cells, examined with a transmission electron microscope, were within the normal range of canine heart morphology in vivo. Resting membrane potential of the cells was about -80 mV when superfused with a Krebs' solution containing 4.7 mM potassium ions. The action potential lasted for 300 msec and had a peak amplitude of about 120 mV. Voltage-clamp experiments demonstrated the presence of an inward calcium current (congruent to 0.9 nA at +9 mV), which was facilitated by isoproterenol (0.1-1 microMs). The background potassium current showed typical inward rectification at potentials more negative than -80 mV. The results indicate that morphological, electrophysiological, and pharmacological properties of the cultured cardiomyocytes were intact. We propose that the culture techniques we have developed can be useful for repeated investigation on functional aspects of cardiac muscles in myocardial disease.
 ...
PMID:Electrophysiological properties of cultured dog myocytes obtained by endomyocardial biopsy. 291 95

Left ventricular biopsies from 376 patients (including 78 patients undergoing bypass surgery) were analyzed by light microscopy (necrosis, infiltration with or without fibrosis) and by immunohistology (bound antibodies). Circulating antisarcolemmal antibodies (ASA) were determined at the time of biopsy using a double-sandwich technique. Circulating antimyolemmal antibodies were assessed in intact rat and human cardiocytes. Histologic findings, heart catheterization, and echocardiography together with the patient's history established the diagnosis of perimyocarditis, myocarditis, postmyocarditic dilated cardiomyopathy, healed myocarditis, and healed perimyocarditis. Both bound and circulating ASA were found in up to 100% of cases in acute inflammatory heart disease and postmyocarditic cardiomyopathy, indicating a secondary immunopathogenesis of the myocardial disease. Analysis of immunoglobulin subclasses revealed: IgG-binding does not discriminate between acute/healing/healed carditis and postmyocarditic dilated heart disease (61.1%-91.7% positive); IgM binding is diagnostic for acute or healing perimyocarditis but has a relatively low incidence (33.3%); IgA binding occurs in acute or healing myocarditis (45.5%), perimyocarditis (33.3%), and in postmyocarditic heart disease (39.4%), but not in controls; complement fixation was never seen in controls, but was seen in acute myocarditis (45.4%), perimyocarditis (25%), and postmyocarditic heart disease (46%). Pretreatment of cryostat sections with collagenase to avoid "nonspecific" binding of antibodies to collagen considerably reduced the sensitivity but increased the specificity. Thus, endomyocardial biopsy proved a safe and valuable method for the further analysis of patients with carditis and myocardial disease of unknown origin.
 ...
PMID:Four years of experience in endomyocardial biopsy--an immunohistologic approach. 391 79

Cardiomyopathy was produced by isoprenaline injections to healthy and hydrazinophthalazine-treated rats. The activity of leukocyte collagenase and collagenolytic cathepsin was determined on the 2nd, 7th, 19th and 21st day after the last isoprenaline injection. At the same time morphological studies of the heart muscles were carried out. It was found that alterations in enzyme activity were different in healthy and hydrazinophthalazine-treated rats. A negative synergism of isoprenaline as regards the hydrazinophthalazine action was observed in biochemical and morphological studies.
 ...
PMID:Leukocyte collagenolytic activity in normal and hydrazinophthalazine-treated rats during isoprenaline-induced cardiomyopathy. 630 34

We have isolated and characterized the human cardiac mast cell (CMC) and compared this novel mast cell (MC type with MC obtained from uterus, skin, and lung. Heart tissue was obtained from 14 patients with cardiomyopathy (CMP, heart transplantation). CMC were isolated by enzymatic digestion using collagenase, pronase-E, hyaluronidase, and DNAse. Substantial amounts of CMC (0.5% to 1.5% of isolated cells) were found in the atrial appendages but not in ventricular digests or other sites of the heart (< 0.1%). In situ staining of atrial tissue revealed the presence of CMC in the myocardium (2.16 +/- 0.7 MC/mm2), endocardium (2.24 +/- 0.9 MC/mm2), and epicardium. As assessed by combined toluidine blue/immunofluorescence staining with monoclonal antibodies (MoAbs), isolated CMC expressed surface IgE, the receptor for stem cell factor (c-kit receptor/CD117), the p24 antigen (CD9), the Pgp-1 homing receptor (CD44), the pan leukocyte antigen (CD45), and the ICAM-1 antigen (CD54). CMC were not recognized by MoAbs to lymphocyte function associated antigen 2 (LFA-2; CD2), T-cell receptor (TcR; CD3), T4 antigen (CD4), LFA-1 alpha-chain (CD11a), C3biR alpha-chain (CD11b), CR4 alpha-chain (CD11c), LPS-R related Ag (CD14), 3-FAL/x-hapten (CD15), Fc gamma RIII (CD16), lactosylceramid (CDw17), the B-cell antigen CD19, or CR1 (CD35). In situ expression of leukocyte antigens on CMC was demonstrable by indirect immunoperoxidase staining technique and double-labeling immunohistochemistry. Almost all CMC (90%) reacted with MoAbs against tryptase and chymase and thus were MCTC. Cardiac mast cells were also stained by the heparin-binding dye Berberine sulfate and expressed measurable amounts of histamine (4.6 +/- 1.4 pg per cell). Cross linking of either IgE receptor or SCF receptor (c-kit) on CMC resulted in histamine secretion (non-specific release: < 6% of total histamine, alpha IgE induced: 12% to 52%; SCF-induced release: 9% to 18%), whereas neither substance P (a skin MC agonist) nor the basophil agonist FMLP showed an effect on CMC. Together, the CMC is an MCTC primarily located in the appendage of the atrium. This novel type of MC exhibits surface membrane antigen and functional properties similar to those of lung and uterus MC.
 ...
PMID:The human cardiac mast cell: localization, isolation, phenotype, and functional characterization. 752 50

Collagen which is present in the myocardium in relatively small amounts is the most abundant structural protein of the connective tissue network. Its structural organization consists of a complex weave of collagen fibers that surrounds and interconnects myocytes, groups of myocytes, muscle fibers and muscle bundles. The conformation of interstitial fibrillar collagen makes it highly resistant to degradation by all proteinases other than specific collagenases. In hearts with myocardial damage secondary to myocardial infarction, chronic ischemia, inflammation, or cardiomyopathy, a complex sequence of compensatory events occur that eventually result in an adverse left ventricular remodeling. This continual state of remodeling is characterized by persistent collagenase activity, fibrillar collagen degradation, and progressive myocyte loss. The net effect is a shift in the balance between collagen synthesis and degradation which leads to an inadequate fibrillar collagen matrix, progressive ventricular dilatation and sphericalization with wall thinning and eventual congestive heart failure.
 ...
PMID:Ventricular remodeling in heart failure: the role of myocardial collagen. 854 Apr 1

Endothelin (ET-1) is found at elevated concentrations in the plasma of patients with heart failure and in animal models of cardiomyopathy. The peptide is a potent positive inotropic agent, the effects of which are mediated by increases in cytosolic Ca2+ in cardiomyocytes. The object of this study was to investigate at the cellular level, the actions of ET-1 on contractile function and on Ca2+ currents in heart-failed ventricular myocardium. Male New Zealand White rabbits (8 wks) were treated with twice weekly injections of epirubicin (4 mg/kg/wk, n = 7) or with saline (n = 7) for 6 wks, followed by a washout period of 2 wks. Ventricular cardiomyocytes were isolated from rabbit hearts using Langendorff perfusion with collagenase; contractile function was examined using a video microscopy method, and L-type Ca2+ currents were recorded using a whole-cell patch-clamp technique. ET-1 produced a concentration-dependent increase in contractile response (% increase from basal value) to a maximum at 1 nM ET-1 of 69 +/- 11% (mean +/- S.D.) in control cardiomyocytes and 33 +/- 6% in heart-failed cells. However, there was no significant change in the EC50 obtained with ET-1 for healthy (0.31 +/- 0.1 nM) and for failed cardiomyocytes (0.24 +/- 0.1 nM). The effects of ET-1 on L-type Ca2+ channels were similar with a peak amplitude at 1 nM ET-1 of -3.26 +/- 0.8 nA in control cardiomyocytes and -3.32 +/- 0.9 nA in heart-failed cells. The attenuation of the contractile response to ET-1 in heart-failed cells may reflect a desensitization of ET receptors as a consequence of elevated circulating levels of ET and was not reflected by alteration of transmembrane Ca2+ conductance. It is probable, therefore, that multiple signalling pathways are involved in the actions of ET on ventricular myocardium.
 ...
PMID:Mechanical effects of ET-1 in cardiomyocytes isolated from normal and heart-failed rabbits. 873 41

Although increased deposition of collagen proteins has been described in cardiomyopathy, little is known of the temporal relationship between events in collagen gene transcription and the occurrence of cardiac fibrosis, the removal of collagen by matrix metalloproteinases (MMPs), or of the regulation of these events by angiotensin AT1 receptors in this disease. We sought to study steady-state collagen mRNA abundance and the deposition of specific collagen subtypes in right and left ventricular muscle of Syrian cardiomyopathic (CMP) hamsters at different stages of cardiomyopathy. Using zymography, we also investigated the gelatinolytic activities of different MMPs to gain some information about collagen removal in experimental hearts. Finally, we investigated the effect of AT1 receptor blockade (losartan) on collagen remodeling. We observed that the mRNA levels of types I and III collagens were significantly increased in all four experimental groups (35, 65, 120, and 200 day) in left ventricular tissue when compared to control (F1-beta strain) values. The mRNA levels of these collagen species in experimental right ventricular tissue samples were only elevated significantly in the 35 and 200 day experimental groups when compared to controls. Fibrillar collagen deposition was elevated in left and right ventricular CMP samples after a lag period from the occurrence of corresponding increases in mRNA abundance. Although 2-week losartan treatment of 65, 120 and 200 day experimental groups had no significant effect on left ventricular fibrillar collagen concentration or collagen mRNA abundance when compared to vehicle-infused CMP hamsters, AT1 receptor blockade was associated with complete regression of cardiac hypertrophy. Both MMP-1 (54 kDa band) and MMP-2 (58 and 62 kDa bands) activities were increased in left ventricular CMP tissues at 65, 120 and 200 days when compared to F1-beta controls. Losartan treatment was associated with significant attenuation of MMP activities in cardiomyopathic samples at 65 and 120 days. Thus, elevation of mRNA abundance of fibrillar collagen genes occurs at very early stages in this model of cardiomyopathy, and corresponding collagen proteins were subsequently deposited in the cardiac interstitium at later stages. As collagen concentration was significantly increased in later stages of cardiomyopathy studied herein (120 and 200 day groups), our data support the hypothesis that collagen synthesis exceeds the capacity of collagen removal during the progression of cardiomyopathy. Nevertheless, cardiac collagen remodeling may be facilitated by elevated MMP activity in cardiomyopathic stages in this experimental model, and we suggested that attenuation of MMP activity in the presence of losartan may be a cardioprotective mechanism of this agent.
 ...
PMID:Cardiac collagen remodeling in the cardiomyopathic Syrian hamster and the effect of losartan. 923 38

The objective of this study was to assess the structural, mechanical and electrophysiological changes associated with chronic administration of epirubicin (Pharmorubicin), which is a cardiotoxic anthracycline antibiotic used in conventional cancer chemotherapy. New Zealand white rabbits (8 weeks) were treated with twice-weekly infusions of epirubicin (2 mg/kg) or saline for a period of 6 weeks, followed by a wash-out period of 2 weeks. Myocardial damage consistent with cardiomyopathy was observed in the epirubicin-treated animals; electron micrographs indicated myofibril loss together with separation of the intercalated disc and dilation of the sarcotubular system. Contractile function, as measured by mechanical shortening, action potentials and L-type Ca2+ currents were examined in ventricular cardiomyocytes, which were isolated by means of enzymatic dissociation using collagenase. There was an attenuation in the contractile response to isoprenaline in cardiomyocytes isolated from the hearts of epirubicin-treated rabbits compared to control rabbits. Cardiomyocytes isolated from epirubicin-treated rabbits had greater basal contractile amplitude (11.0+/-0.3 %dL, n=8) than control myocytes (8.2+/-0.3 %dL, n=9), but had similar maximum responses of 19.1+/-0.6 %dL, and 17.3+/-0.5 %dL, respectively, when stimulated with 1 microM isoprenaline. No differences were noted in the peak L-type Ca2+ current of myocytes isolated from the hearts of control and epirubicin-treated rabbits; however, in the latter, there was a prolongation of the action potential duration (396+/-25 ms) compared to that in controls (321+/-26 ms). These results demonstrate structural and mechanical alterations in ventricular cardiomyocytes which are compatable with a mild cardiomyopathy following chronic treatment with the anthracycline, epirubicin. The increase in basal contraction is likely to be due to more efficient coupling of electrical stimulation, and the depressed inotropic responsiveness following stimulation with isoprenaline indicates that there may be changes in cell membrane properties. Compared to control cardiomyocytes, cells isolated from the hearts of epirubicin-treated rabbits were more heterogeneous, with respect to cell dimensions, and had significantly different electromechanical properties.
 ...
PMID:Characterisation of a cellular model of cardiomyopathy, in the rabbit, produced by chronic administration of the anthracycline, epirubicin. 944 44

The myocardium contains a collagen matrix composed primarily of collagen and fibronectin, which are major determinants of the myocardial architecture, structural integrity and mechanical properties. The present study was undertaken to determine the age-related changes of the accumulation and degradation of the collagen matrix in Syrian myopathic hamsters, of the Bio 14.6 and Bio 53.58 strains. Those hamsters were used as models for hypertrophic and dilated cardiomyopathy, respectively. The heart to body weight ratio in the Bio 14.6 strains was higher (P<0.05) than that in the age-matched F1b strains. In the Bio 53.58 strains, the heart to body weight ratio was higher at 8 and 42 weeks of age than that in the F1b strains. The collagen content increased from 22 weeks of age in both Bio hamsters compared with age-matched F1b hamsters (P<0.05). In both cardiomyopathic hamsters, the mRNA expressions for type I and type III collagen and fibronectin all increased with aging; however, the fibronectin expression in the Bio 14.6 strains increased more at 22 weeks of age than at 42 weeks of age. The left ventricular MMP-1, MMP-2 and MMP-9 activities in Bio 53.58 strains increased with aging. However, in the Bio 14.6 strains, although MMP-1 activities increased with aging, MMP-2 and MMP-9 activities decreased at 42 weeks of age in comparison to those at 22 weeks of age. Thus, the MMP activation differed between two cardiomyopathic models at the stage of heart failure, although the collagen synthesis was elevated in both models. In conclusion, it would seem that the relative balance between the synthesis and the removal of collagen may contribute to the changes in the left ventricular geometry in two different types of cardiomyopathy.
 ...
PMID:Extracellular matrix regulation in the development of Syrian cardiomyopathic Bio 14.6 and Bio 53.58 hamsters. 1047 45

The present study was undertaken to determine the effects of AT1 receptor blockade which occurred in response to losartan, on the extracellular matrix (ECM) degradation process in the Bio 14.6 (n = 12) and Bio 53.58 (n = 12) strains which are referred as models of hypertrophic and dilated cardiomyopathy, respectively. The administration of losartan (30 mg/kg/day) in hamsters from 10-20 weeks of age reduced the accumulation of the left ventricular collagen matrix in both of the Bio 14.6 and the Bio 53.58 strains. According to the RT-PCR, the levels of mRNA for matrix metalloproteinase (MMP) and the tissue inhibitor of MMP (TIMP) were examined. MMP-1, -2, -3, and -9 were more enhanced in both myopathic strains than in the control F1beta, strains. With losartan, the levels of MMP-1, -2, -9, TIMP-1 and -2 decreased in the both strains but those for MMP-3 did not in Bio 14.6 strains. TIMP-3 and -4 mRNA levels did not change in any of the experimental hamsters, whether treated or untreated with losartan. The Western blots also showed similar observations in the both strains as seen in mRNA expressions although MMP-2 in the Bio 53.58 strains did not differ between treated and untreated with losartan. Although losartan has an inhibitory effect on collagen accumulation in the development of cardiomyopathy, MMPs (-1, -2, -9) and TIMPs (-1, -2) seem to be susceptible to responding to losartan in Bio cardiomyopathic hamsters.
 ...
PMID:Effects of losartan on the collagen degradative enzymes in hypertrophic and congestive types of cardiomyopathic hamsters. 1169 96


1 2 3 Next >>