Postconditioning for salvage of ischemic skeletal muscle from reperfusion injury: efficacy and mechanism

2008 ◽  
Vol 295 (2) ◽  
pp. R681-R689 ◽  
Author(s):  
Sandra E. McAllister ◽  
Homa Ashrafpour ◽  
Neil Cahoon ◽  
Ning Huang ◽  
Michael A. Moses ◽  
...  

We tested our hypothesis that postischemic conditioning (PostC) is effective in salvage of ischemic skeletal muscle from reperfusion injury and the mechanism involves inhibition of opening of the mitochondrial permeability transition pore (mPTP). In bilateral 8 × 13 cm pig latissimus dorsi muscle flaps subjected to 4 h ischemia, muscle infarction increased from 22 ± 4 to 41 ± 1% between 2 and 24 h reperfusion and remained unchanged at 48 (38 ± 6%) and 72 (40 ± 1%) h reperfusion ( P < 0.05; n = 4 pigs). PostC induced by four cycles of 30-s reperfusion/reocclusion at the onset of reperfusion after 4 h ischemia reduced muscle infarction from 44 ± 2 to 22 ± 2% at 48 h reperfusion. This infarct protective effect of PostC was mimicked by intravenous injection of the mPTP opening inhibitor cyclosporin A or NIM-811 (10 mg/kg) at 5 min before the end of 4 h ischemia and was abolished by intravenous injection of the mPTP opener atractyloside (10 mg/kg) at 5 min before PostC ( P < 0.05; n = 4–5 pigs). PostC or intravenous cyclosporin A injection at 5 min before reperfusion caused a decrease in muscle myeloperoxidase activity and mitochondrial free Ca2+ concentration and an increase in muscle ATP content after 4 h ischemia and 2 h reperfusion compared with the time-matched controls. These effects of PostC were abolished by intravenous injection of atractyloside at 5 min before PostC ( P < 0.05; n = 6 pigs). These observations support our hypothesis that PostC is effective in salvage of ischemic skeletal muscle from reperfusion injury and the mechanism involves inhibition of opening of the mPTP.

2009 ◽  
Vol 106 (1) ◽  
pp. 20-28 ◽  
Author(s):  
Sandra E. McAllister ◽  
Michael A. Moses ◽  
Kunaal Jindal ◽  
Homa Ashrafpour ◽  
Neil J. Cahoon ◽  
...  

Administration of Na+/H+ exchange isoform-1 (NHE-1) inhibitors before ischemia has been shown to attenuate myocardial infarction in several animal models of ischemia-reperfusion injury. However, controversy still exists as to the efficacy of NHE-1 inhibitors in protection of myocardial infarction when administered at the onset of reperfusion. Furthermore, the efficacy of NHE-1 inhibition in protection of skeletal muscle from infarction (necrosis) has not been studied. This information has potential clinical applications in prevention or salvage of skeletal muscle from ischemia-reperfusion injury in elective and trauma reconstructive surgery. The objective of this research project is to test our hypothesis that the NHE-1 inhibitor cariporide is effective in protection of skeletal muscle from infarction when administered at the onset of sustained ischemia or reperfusion and to study the mechanism of action of cariporide. In our studies, we observed that intravenous administration of cariporide 10 min before ischemia (1 or 3 mg/kg) or reperfusion (3 mg/kg) significantly reduced infarction in pig latissimus dorsi muscle flaps compared with the control, when these muscle flaps were subjected to 4 h of ischemia and 48 h of reperfusion ( P < 0.05; n = 5 pigs/group). Both preischemic and postischemic cariporide treatment (3 mg/kg) induced a significant decrease in muscle myeloperoxidase activity and mitochondrial-free Ca2+ content and a significant increase in muscle ATP content within 2 h of reperfusion ( P < 0.05; n = 4 pigs/group). Preischemic and postischemic cariporide treatment (3 mg/kg) also significantly inhibited muscle NHE-1 protein expression within 2 h of reperfusion after 4 h of ischemia, compared with the control ( P < 0.05; n = 3 pigs/group). These observations support our hypothesis that cariporide attenuates skeletal muscle infarction when administered at the onset of ischemia or reperfusion, and the mechanism involves attenuation of neutrophil accumulation and mitochondrial-free Ca2+ overload and preservation of ATP synthesis in the early stage of reperfusion.


2007 ◽  
Vol 292 (3) ◽  
pp. E748-E755 ◽  
Author(s):  
Peter J. Adhihetty ◽  
Vladimir Ljubicic ◽  
David A. Hood

Chronic contractile activity of skeletal muscle induces an increase in mitochondria located in proximity to the sarcolemma [subsarcolemmal (SS)] and in mitochondria interspersed between the myofibrils [intermyofibrillar (IMF)]. These are energetically favorable metabolic adaptations, but because mitochondria are also involved in apoptosis, we investigated the effect of chronic contractile activity on mitochondrially mediated apoptotic signaling in muscle. We hypothesized that chronic contractile activity would provide protection against mitochondrially mediated apoptosis despite an elevation in the expression of proapoptotic proteins. To induce mitochondrial biogenesis, we chronically stimulated (10 Hz; 3 h/day) rat muscle for 7 days. Chronic contractile activity did not alter the Bax/Bcl-2 ratio, an index of apoptotic susceptibility, and did not affect manganese superoxide dismutase levels. However, contractile activity increased antiapoptotic 70-kDa heat shock protein and apoptosis repressor with a caspase recruitment domain by 1.3- and 1.4-fold ( P < 0.05), respectively. Contractile activity elevated SS mitochondrial reactive oxygen species (ROS) production 1.4- and 1.9-fold ( P < 0.05) during states IV and III respiration, respectively, whereas IMF mitochondrial state IV ROS production was suppressed by 28% ( P < 0.05) and was unaffected during state III respiration. Following stimulation, exogenous ROS treatment produced less cytochrome c release (25–40%) from SS and IMF mitochondria, and also reduced apoptosis-inducing factor release (≈30%) from IMF mitochondria, despite higher inherent cytochrome c and apoptosis-inducing factor expression. Chronic contractile activity did not alter mitochondrial permeability transition pore (mtPTP) components in either subfraction. However, SS mitochondria exhibited a significant increase in the time to Vmax of mtPTP opening. Thus, chronic contractile activity induces predominantly antiapoptotic adaptations in both mitochondrial subfractions. Our data suggest the possibility that chronic contractile activity can exert a protective effect on mitochondrially mediated apoptosis in muscle.


Circulation ◽  
2007 ◽  
Vol 116 (suppl_16) ◽  
Author(s):  
Jinkun Xi ◽  
Huihua Wang ◽  
Guillaume Chanoit ◽  
Guang Cheng ◽  
Robert A Mueller ◽  
...  

Although resveratrol has been demonstrated to be cardioprotective, the detailed cellular and molecular mechanisms that mediate the protection remain elusive. We aimed to determine if resveratrol protects the heart at reperfusion by modulating the mitochondrial permeability transition pore (mPTP) opening through glycogen synthase kinase 3β (GSK-3β). Resveratrol (10μM) given at reperfusion reduced infarct size (12.2 ± 2.5 % of risk zone vs. 37.9 ± 3.1 % of risk zone in control, n = 6) in isolated rat hearts subjected to 30 min regional ischemia followed by 2 h of reperfusion, an effect that was abrogated by the mPTP opener atractyloside (30.9 ± 8.1 % of risk zone), implying that resveratrol may protect the heart at reperfusion by modulating the mPTP opening. To define the signaling mechanism underlying the action of resveratrol, we determined GSK-3β activity by measuring its phosphorylation at Ser 9 . Resveratrol significantly enhanced GSK-3β phosphorylation upon reperfusion (225.2 ± 30.0 % of control at 5 min of reperfusion). Further experiments showed that resveratrol induces translocation of GSK-3β to mitochondria and translocated GSK-3β interacts with the mPTP component cyclophilin D but not VDAC (the voltage-dependent anion channel) or ANT (the adenine nucleotide translocator) in cardiac mitochondria. Taken together, these data suggest that resveratrol prevents myocardial reperfusion injury by targeting the mPTP opening via GSK-3β. Translocation of GSK-3β to mitochondria and its interaction with the mPTP component cyclophilin D may serve as an essential mechanism that mediates the protective effect of resveratrol on reperfusion injury.


1998 ◽  
Vol 143 (1) ◽  
pp. 217-224 ◽  
Author(s):  
Robert Eskes ◽  
Bruno Antonsson ◽  
Astrid Osen-Sand ◽  
Sylvie Montessuit ◽  
Christoph Richter ◽  
...  

Bcl-2 family members either promote or repress programmed cell death. Bax, a death-promoting member, is a pore-forming, mitochondria-associated protein whose mechanism of action is still unknown. During apoptosis, cytochrome C is released from the mitochondria into the cytosol where it binds to APAF-1, a mammalian homologue of Ced-4, and participates in the activation of caspases. The release of cytochrome C has been postulated to be a consequence of the opening of the mitochondrial permeability transition pore (PTP). We now report that Bax is sufficient to trigger the release of cytochrome C from isolated mitochondria. This pathway is distinct from the previously described calcium-inducible, cyclosporin A–sensitive PTP. Rather, the cytochrome C release induced by Bax is facilitated by Mg2+ and cannot be blocked by PTP inhibitors. These results strongly suggest the existence of two distinct mechanisms leading to cytochrome C release: one stimulated by calcium and inhibited by cyclosporin A, the other Bax dependent, Mg2+ sensitive but cyclosporin insensitive.


2019 ◽  
Vol 20 (2) ◽  
pp. 404 ◽  
Author(s):  
Rebekka Jensen ◽  
Ioanna Andreadou ◽  
Derek Hausenloy ◽  
Hans Bøtker

Ischemia reperfusion injury (IR injury) associated with ischemic heart disease contributes significantly to morbidity and mortality. O-linked β-N-acetylglucosamine (O-GlcNAc) is a dynamic posttranslational modification that plays an important role in numerous biological processes, both in normal cell functions and disease. O-GlcNAc increases in response to stress. This increase mediates stress tolerance and cell survival, and is protective. Increasing O-GlcNAc is protective against IR injury. Experimental cellular and animal models, and also human studies, have demonstrated that protection against IR injury by ischemic preconditioning, and the more clinically applicable remote ischemic preconditioning, is associated with increases in O-GlcNAc levels. In this review we discuss how the principal mechanisms underlying tissue protection against IR injury and the associated immediate elevation of O-GlcNAc may involve attenuation of calcium overload, attenuation of mitochondrial permeability transition pore opening, reduction of endoplasmic reticulum stress, modification of inflammatory and heat shock responses, and interference with established cardioprotective pathways. O-GlcNAcylation seems to be an inherent adaptive cytoprotective response to IR injury that is activated by mechanical conditioning strategies.


2005 ◽  
Vol 280 (16) ◽  
pp. 15579-15586 ◽  
Author(s):  
Victor V. Lemeshko ◽  
Mauricio Arias ◽  
Sergio Orduz

Bacillus thuringiensissubsp.medellinis known to produce the Cry11Bb protein of 94 kDa, which is toxic for mosquito larvae due to permeabilization of the plasma membrane of midgut epithelial cells. Earlier we found that a 2.8-kDa novel peptide BTM-P1, which was artificially synthesized taking into account the primary structure of Cry11Bb endotoxin, is active against several species of bacteria. In this work we show that BTM-P1 induces cyclosporin A-insensitive swelling of rat liver mitochondria in various salt solutions but not in the sucrose medium. Inorganic phosphate and Ca2+significantly increased this effect of the peptide. The uncoupling action of BTM-P1 on oxidative phosphorylation was stronger in the potassium-containing media and correlated with a decrease of the inner membrane potential of mitochondria. In isotonic KNO3, KCl, or NH4NO3media, a complete drop of the inner membrane potential was observed at 1–2 μg/ml of the peptide. The peptide-induced swelling was increased by energization of mitochondria in the potassium-containing media, but it was inhibited in the NaNO3, NH4NO3, and Tris-NO3media. All mitochondrial effects of the peptide were completely prevented by adding a single N-terminal tryptophan residue to the peptide sequence. We suggest a mechanism of membrane permeabilization that includes a transmembrane- and surface potential-dependent insertion of the polycation peptide into the lipid bilayer and its oligomerization leading to formation of ion channels and also to the mitochondrial permeability transition pore opening in a cyclosporin A-insensitive manner.


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