scholarly journals Cardiac Electrophysiological Alterations in Heart/Muscle-Specific Manganese-Superoxide Dismutase-Deficient Mice: Prevention by a Dietary Antioxidant Polyphenol

2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
Tadahiro Sunagawa ◽  
Takahiko Shimizu ◽  
Akio Matsumoto ◽  
Motoyuki Tagashira ◽  
Tomomasa Kanda ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Superoxide Dismutase ◽  
Action Potential ◽  
Heart Muscle ◽  
Chronic Exposure ◽  
Manganese Superoxide Dismutase ◽  
Left Ventricular ◽  
Protective Effects ◽  
Manganese Superoxide ◽  
Dietary Antioxidant

Cardiac electrophysiological alterations induced by chronic exposure to reactive oxygen species and protective effects of dietary antioxidant have not been thoroughly examined. We recorded surface electrocardiograms (ECG) and evaluated cellular electrophysiological abnormalities in enzymatically-dissociated left ventricular (LV) myocytes in heart/muscle-specific manganese-superoxide dismutase-deficient (H/M-Sod2−/−) mice, which exhibit dilated cardiomyopathy due to increased oxidative stress. We also investigated the influences of intake of apple polyphenols (AP) containing mainly procyanidins with potent antioxidant activity. The QRS and QT intervals of ECG recorded in H/M-Sod2−/−mice were prolonged. The effective refractory period in the LV myocardium of H/M-Sod2−/−mice was prolonged, and susceptibility to ventricular tachycardia or fibrillation induced by rapid ventricular pacing was increased. Action potential duration in H/M-Sod2−/−LV myocytes was prolonged, and automaticity was enhanced. The density of the inwardly rectifier K+current (IK1) was decreased in the LV cells of H/M-Sod2−/−mice. The AP intake partially improved these electrophysiological alterations and extended the lifespan in H/M-Sod2−/−mice. Thus, chronic exposure of the heart to oxidative stress produces a variety of electrophysiological abnormalities, increased susceptibility to ventricular arrhythmias, and action potential changes associated with the reduced density ofIK1. Dietary intake of antioxidant nutrients may prevent oxidative stress-induced electrophysiological disturbances.

scholarly journals Heat Shock Protein 72 Enhances Manganese Superoxide Dismutase Activity During Myocardial Ischemia-Reperfusion Injury, Associated With Mitochondrial Protection and Apoptosis Reduction

Circulation ◽  
2002 ◽  
Vol 106 (12_suppl_1) ◽  
Author(s):  
Ken Suzuki ◽  
Bari Murtuza ◽  
Ivan A. Sammut ◽  
Najma Latif ◽  
Jay Jayakumar ◽  
...  
Keyword(s):  
Superoxide Dismutase ◽  
Heat Shock ◽  
Heat Shock Protein ◽  
Reperfusion Injury ◽  
Manganese Superoxide Dismutase ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Left Ventricular ◽  
Heat Shock Protein 72 ◽  
Manganese Superoxide

Background Heat shock protein 72 (HSP72) is known to provide myocardial protection against ischemia-reperfusion injury by its chaperoning function. Target molecules of this effect are presumed to include not only structural proteins but also other self-preservation proteins. The details, however, remain unknown. Manganese superoxide dismutase (Mn-SOD) is an enzyme that preserves mitochondria, a key organelle for cellular respiration, from reperfusion injury and limits mitochondria-related apoptosis. We hypothesized that Mn-SOD would play a role in HSP72-mediated cardioprotection. Methods and Results Rat hearts were transfected with human HSP72 by intra-coronary infusion of Hemagglutinating Virus of Japan-liposome, resulting in global myocardial overexpression of HSP72. After ischemia-reperfusion injury, cardiac function (left ventricular systolic pressure, maximum dP/dt, minimum dP/dt, and coronary flow) was improved in the HSP72-transfected hearts compared with control-transfected ones, corresponding with less leakage of creatine kinase and mitochondrial aspartate aminotransferase. Postischemic Mn-SOD content and activity in the HSP72-transfected hearts were enhanced in comparison with the controls (content: 96.9±4.1 versus 85.5±2.5% to the preischemic level, P =0.038; activity: 93.9±2.2 versus 82.2±3.7%, P =0.022), associated with improved mitochondrial respiratory function (postischemic percent respiratory control index; NAD + -linked: 81.3±3.8 versus 18.5±4.4%; FAD-linked: 71.8±5.5 versus 20.7±5.3%, P <0.001). In addition, incidence of postischemic cardiomyocyte apoptosis was attenuated in the HSP72-transfected hearts (4.0±1.1 versus 10.3±3.3%, P =0.036), correlating with an increased Bcl-2 level and reduced up-regulation of caspase-3. Conclusions These data suggest that the enhanced Mn-SOD activity during ischemia-reperfusion injury, which is associated with mitochondrial protection and apoptosis reduction, is a possible mechanism of HSP72-induced cardioprotection.

scholarly journals Neutral Sphingomyelinase Modulation in the Protective/Preventive Role of rMnSOD from Radiation-Induced Damage in the Brain

2019 ◽  
Vol 20 (21) ◽  
pp. 5431 ◽  
Author(s):  
Samuela Cataldi ◽  
Antonella Borrelli ◽  
Maria Rachele Ceccarini ◽  
Irina Nakashidze ◽  
Michela Codini ◽  
...  
Keyword(s):  
Superoxide Dismutase ◽  
Manganese Superoxide Dismutase ◽  
Nuclear Research ◽  
Protective Effects ◽  
Manganese Superoxide ◽  
Additional Group ◽  
Gene And Protein Expression ◽  
Radiation Induced ◽  
The Brain ◽  
Preventive Role

Studies on the relationship between reactive oxygen species (ROS)/manganese superoxide dismutase (MnSOD) and sphingomyelinase (SMase) are controversial. It has been demonstrated that SMase increases the intracellular ROS level and induces gene expression for MnSOD protein. On the other hand, some authors showed that ROS modulate the activation of SMase. The human recombinant manganese superoxide dismutase (rMnSOD) exerting a radioprotective effect on normal cells, qualifies as a possible pharmaceutical tool to prevent and/or cure damages derived from accidental exposure to ionizing radiation. This study aimed to identify neutral SMase (nSMase) as novel molecule connecting rMnSOD to its radiation protective effects. We used a new, and to this date, unique, experimental model to assess the effect of both radiation and rMnSOD in the brain of mice, within a collaborative project among Italian research groups and the Joint Institute for Nuclear Research, Dubna (Russia). Mice were exposed to a set of minor γ radiation and neutrons and a spectrum of neutrons, simulating the radiation levels to which cosmonauts will be exposed during deep-space, long-term missions. Groups of mice were treated or not-treated (controls) with daily subcutaneous injections of rMnSOD during a period of 10 days. An additional group of mice was also pretreated with rMnSOD for three days before irradiation, as a model for preventive measures. We demonstrate that rMnSOD significantly protects the midbrain cells from radiation-induced damage, inducing a strong upregulation of nSMase gene and protein expression. Pretreatment with rMnSOD before irradiation protects the brain with a value of very high nSMase activity, indicating that high levels of activity might be sufficient to exert the rMnSOD preventive role. In conclusion, the protective effect of rMnSOD from radiation-induced brain damage may require nSMase enzyme.

scholarly journals Role of reduced manganese superoxide dismutase in ischemia-reperfusion injury: a possible trigger for autophagy and mitochondrial biogenesis?

2013 ◽  
Vol 304 (3) ◽  
pp. F257-F267 ◽  
Author(s):  
Nirmala Parajuli ◽  
Lee Ann MacMillan-Crow
Keyword(s):  
Oxidative Stress ◽  
Superoxide Dismutase ◽  
Renal Function ◽  
Mitochondrial Biogenesis ◽  
Renal Damage ◽  
Manganese Superoxide Dismutase ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Manganese Superoxide ◽  
Oxidant Production

Excessive generation of superoxide and mitochondrial dysfunction has been described as being important events during ischemia-reperfusion (I/R) injury. Our laboratory has demonstrated that manganese superoxide dismutase (MnSOD), a major mitochondrial antioxidant that eliminates superoxide, is inactivated during renal transplantation and renal I/R and precedes development of renal failure. We hypothesized that MnSOD knockdown in the kidney augments renal damage during renal I/R. Using newly characterized kidney-specific MnSOD knockout (KO) mice the extent of renal damage and oxidant production after I/R was evaluated. These KO mice (without I/R) exhibited low expression and activity of MnSOD in the distal nephrons, had altered renal morphology, increased oxidant production, but surprisingly showed no alteration in renal function. After I/R the MnSOD KO mice showed similar levels of injury to the distal nephrons when compared with wild-type mice. Moreover, renal function, MnSOD activity, and tubular cell death were not significantly altered between the two genotypes after I/R. Interestingly, MnSOD KO alone increased autophagosome formation, mitochondrial biogenesis, and DNA replication/repair within the distal nephrons. These findings suggest that the chronic oxidative stress as a result of MnSOD knockdown induced multiple coordinated cell survival signals including autophagy and mitochondrial biogenesis, which protected the kidney against the acute oxidative stress following I/R.

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