cytochrome-c-t and Cardiomyopathy--Dilated

Edaravone, a novel antioxidant, acts by trapping hydroxyl radicals, quenching active oxygen and so on. Its cardioprotective activity against experimental autoimmune myocarditis (EAM) was reported. Nevertheless, it remains to be determined whether edaravone protects against cardiac remodelling in dilated cardiomyopathy (DCM). The present study was undertaken to assess whether edaravone attenuates myocardial fibrosis, and examine the effect of edaravone on cardiac function in rats with DCM after EAM. Rat model of EAM was prepared by injection with porcine cardiac myosin 28 days after immunization, we administered edaravone intraperitoneally at 3 and 10 mg/kg/day to rats for 28 days. The results were compared with vehicle-treated rats with DCM. Cardiac function, by haemodynamic and echocardiographic study and histopathology were performed. Left ventricular (LV) expression of NADPH oxidase subunits (p47(phox), p67(phox), gp91(phox) and Nox4), fibrosis markers (TGF-β(1) and OPN), endoplasmic reticulum (ER) stress markers (GRP78 and GADD 153) and apoptosis markers (cytochrome C and caspase-3) were measured by Western blotting. Edaravone-treated DCM rats showed better cardiac function compared with those of the vehicle-treated rats. In addition, LV expressions of NADPH oxidase subunits levels were significantly down-regulated in edaravone-treated rats. Furthermore, the number of collagen-III positive cells in the myocardium of edaravone-treated rats was lower compared with those of the vehicle-treated rats. Our results suggest that edaravone ameliorated the progression of DCM by modulating oxidative and ER stress-mediated myocardial apoptosis and fibrosis.

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Antioxidants; Antipyrine; Apoptosis; Autoimmune Diseases; Blotting, Western; Cardiac Myosins; Cardiomyopathy, Dilated; Caspase 3; Cytochromes c; Down-Regulation; Edaravone; Endomyocardial Fibrosis; Endoplasmic Reticulum Stress; Heart Ventricles; In Situ Nick-End Labeling; Male; Myocarditis; NADPH Oxidases; Oxidative Stress; Rats; Rats, Inbred Lew; Swine

Cytochrome P450 2E1 (CYP2E1) is a cytochrome P450 enzyme that catalyzes the metabolism of toxic substrates. CYP2E1 is upregulated in heart disease, including the dilated cardiomyopathy (DCM) mouse model. Here, knockdown of CYP2E1 significantly ameliorated the dilated left ventricle, thin wall, and dysfunctional contraction in the cTnT(R141W) and adriamycin-induced DCM mouse models. Interstitial fibrosis, poorly organized myofibrils, and swollen mitochondria with loss of cristae were improved in the myocardium of α-myosin heavy chain (MHC)-cTnT(R141W)×CYP2E1-silence double-transgenic mice when compared with the cTnT(R141W) transgenic mice. Oxidative stress, the activation of caspase 3 and caspase 9, the release of cytochrome c, and the apoptosis in the myocardium were significantly decreased in double-transgenic mice compared with the cTnT(R141W) transgenic mice. In summary, the expression of CYP2E1 is upregulated in heart disease and might be induced by hypoxemia in cardiomyopathy. The overexpression of CYP2E1 can enhance the metabolism of endogenous ketones to meet the energy demand of the heart in certain disease states, but the overexpression of CYP2E1 can also increase oxidative stress and apoptosis in the DCM heart. Knockdown or downregulation of CYP2E1 might be a therapeutic strategy to control the development of DCM after mutations of cTnT(R141W) or other factors, because DCM is the third most common cause of heart failure and the most frequent cause of heart transplantation.

Topics: Amino Acid Substitution; Animals; Apoptosis; Cardiomyopathy, Dilated; Cytochrome P-450 CYP2E1; Cytochromes c; Doxorubicin; Echocardiography; Glutathione; Heart Ventricles; HEK293 Cells; Humans; Hydrogen Peroxide; Immunoblotting; Kaplan-Meier Estimate; Mice; Mice, Inbred C57BL; Mice, Transgenic; Microscopy, Electron, Transmission; Mitochondria, Heart; Myocardium; Oxidative Stress; Reverse Transcriptase Polymerase Chain Reaction; RNA Interference; Troponin T

Programmed cell death of cardiomyocytes following myocardial ischemia increases biomechanical stress on the remaining myocardium, leading to myocardial dysfunction that may result in congestive heart failure or sudden death. Nogo-A is well characterized as a potent inhibitor of axonal regeneration and plasticity in the central nervous system, however, the role of Nogo-A in non-nervous tissues is essentially unknown. In this study, Nogo-A expression was shown to be significantly increased in cardiac tissue from patients with dilated cardiomyopathy and from patients who have experienced an ischemic event. Nogo-A expression was clearly associated with cardiomyocytes in culture and was localized predominantly in the endoplasmic reticulum. In agreement with the findings from human tissue, Nogo-A expression was significantly increased in cultured neonatal rat cardiomyocytes subjected to hypoxia/reoxygenation. Knockdown of Nogo-A in cardiomyocytes markedly attenuated hypoxia/reoxygenation-induced apoptosis, as indicated by the significant reduction of DNA fragmentation, phosphatidylserine translocation, and caspase-3 cleavage, by a mechanism involving the preservation of mitochondrial membrane potential, the inhibition of ROS accumulation, and the improvement of intracellular calcium regulation. Together, these data demonstrate that knockdown of Nogo-A may serve as a novel therapeutic strategy to prevent the loss of cardiomyocytes following ischemic/hypoxic injury.

Topics: Animals; Apoptosis; Calcium; Cardiomyopathy, Dilated; Caspase 3; Cell Hypoxia; Cytochromes c; Disease Models, Animal; DNA Fragmentation; Endoplasmic Reticulum; Gene Knockdown Techniques; Humans; Membrane Potential, Mitochondrial; Mitochondria; Myelin Proteins; Myocardial Ischemia; Myocytes, Cardiac; Nogo Proteins; Phosphatidylserines; Rats; Reactive Oxygen Species

We investigated whether early combined autologous adipose-derived mesenchymal stem cell (ADMSC) and sildenafil therapy offers an additive benefit in preserving heart function in rat dilated cardiomyopathy (DCM).. Adult Lewis rats (n = 8 per group) were divided into group 1 (normal control), group 2 (saline-treated DCM rats), group 3 [2.0 × 106 ADMSC implanted into left ventricular (LV) myocardium of DCM rats], group 4 (DCM rats with sildenafil 30 mg/kg/day, orally), and group 5 (DCM rats with combined ADMSC-sildenafil). Treatment was started 1 week after DCM induction and the rats were sacrificed on day 90.. The results showed that mitochondrial protein expressions of connexin43 and cytochrome-C were lowest in group 2, and lower in groups 3 and 4 than in group 5 (p < 0.002). Conversely, oxidative index was highest in group 2, and also higher in groups 3 and 4 than in group 5 (p < 0.0003). The mRNA expressions of interleukin (IL)-10, Gro/IL-8, endothelial nitric oxide synthase, and Bcl-2 were lowest in group 2, and lower in groups 3 and 4 compared with group 5 (p < 0.0001). The mRNA expressions of matrix metalloproteinase-9, Bax, caspase 3, and stromal-cell derived factor-1α were highest in group 2, and higher in groups 3 and 4 than in group 5 (p < 0.0004). Apoptosis and fibrosis in LV myocardium were most prominent in group 2 and higher in groups 3 and 4 than in group 5, whereas angiogenesis and LV ejection fraction were lowest in group 2 and lower in groups 3 and 4 than in group 5 (p < 0.003).. Early combined ADMSC/sildenafil is superior to either treatment alone in preserving LV function.

Topics: Adipose Tissue; Animals; Apoptosis; Body Weight; Cardiomyopathy, Dilated; Connexin 43; Cytochromes c; Flow Cytometry; Immunohistochemistry; Male; Mesenchymal Stem Cells; Organ Size; Oxidative Stress; Phosphodiesterase Inhibitors; Piperazines; Purines; Rats; Rats, Inbred Lew; Reverse Transcriptase Polymerase Chain Reaction; Sildenafil Citrate; Sulfones; Ultrasonography