Novel bisindolylmaleimide derivative inhibits mitochondrial permeability transition pore and protects the heart from reperfusion injury.

Despite major advances in treating patients with coronary heart disease, reperfusion injury is still considered to be a major problem, especially in surgical settings. Here, we demonstrate the protective effects of a novel bisindolylmaleimide derivative, MS1 (2-[1-(3-aminopropyl)indol-3-yl]-3-(indol-3-yl)-N-methylmaleimide), against reperfusion injury of the heart. After anesthesia and artificial ventilation, Wistar rats were subjected to 30 min of left coronary artery occlusion followed by 120 min of reperfusion with or without treating the rats with MS1 (2.25 mumol.L-1.kg-1) before left coronary artery occlusion. Compared with the untreated hearts, MS1 treatment significantly reduced myocardial infarct size (35.1% +/- 3% vs. 75.5% +/- 5%, p < 0.001), reduced prevalence of apoptotic cells (2.6% +/- 0.5% vs. 12.2% +/- 2.1%, p < 0.001), prevented mitochondrial swelling and cytochrome c release, inhibited downregulation of antiapoptotic protein Bcl-2 expression, and suppressed caspase-3 activation. In contrast, pretreatment with atractyloside, a mitochondrial permeability transition pore opener, abolished the protective effects of MS1. In conclusion, MS1 inhibits pathologic opening of permeability transition pores and protects the heart against reperfusion injury and pathologic apoptosis.

A novel bisindolylmaleimide derivative enhances functional recovery of heart after long-term hypothermic heart preservation.

BACKGROUND: Functional recovery following heart transplantation mainly depends on the ability of preservative solution in providing the physical and biochemical environment so as to maintain the viability of the tissue during preservation and in reperfusion. Here we demonstrate the protective effects of a novel bisindolylmaleimide derivative, MS1, on enhancing the functional recovery of the heart following long-term hypothermic preservation when added to the preservative solution. METHODS: After anesthesia and artificial ventilation, the hearts were rapidly isolated and perfused with Kreb's Henseleit buffer at 37 degrees C in working mode. After 30 minutes of perfusion, the hearts were arrested with cardioplegic solution and preserved in University of Wisconsin solution with (UW-MS1 group) or without MS1 (UW-Vehicle group) for 12 h at 4 degrees C. After 12 hours, the hearts were reperfused for 60 minutes. RESULTS: MS1 treated hearts showed: a) significant recovery of cardiac functions (P<0.001), b) well-preserved myocardial ATP levels (P<0.001), c) less myocardial water content (P<0.01), d) reduced oxidative stress (P<0.001), e) less intracellular swelling and well-preserved mitochondria, and g) activation of cell survival cascades compared to the control hearts preserved in UW solution without MS1. In contrast, these protective effects of MS1 were abolished on opening the permeability transition pore before MS1 treatment. CONCLUSION: These results altogether indicate the efficacy of this compound in protecting the myocardium against reperfusion injury and thus making this drug a clinically useful tool in patients undergoing reperfusion after cardiac surgeries.

Second window of ischemic preconditioning regulates mitochondrial permeability transition pore by enhancing Bcl-2 expression.

OBJECTIVE: The second window of protection (SWOP) following brief coronary artery occlusion begins at 24 h and may last up to 72 h and occurs via many unknown mechanisms. We investigated the role of the mitochondrial permeability transition pore (PTP), a non specific pore in the inner membrane of the mitochondria in this phenomenon. METHODS: Ischemic preconditioning (IP) was induced in Wistar rats by left coronary artery occlusion (four, 3-min episodes separated by 10 min of reperfusion) on day 1. On day 2, ischemia was induced with 30 min of ischemia and 120 min of reperfusion in IP and control rats. RESULTS: IP rats showed decreased myocardial infarction (MI) area vs. non-IP control rats (15.32 vs. 45.6%). Furthermore, IP rats had preserved cardiac function (heart rate, rate pressure product, coronary flow and aortic flow) and myocardial ATP (P<0.03), decreased tissue water content (73.2 vs. 90.6%), increased expression of Bcl-2, and less mitochondrial swelling, cytochrome C release and apoptosis (2.6 vs. 12.4%) when compared to sham-operated rats. Activation of the permeability transition pore with PTP activators lonidamine (10 mg/kg body weight) or atractyloside (5 mg/kg body weight) before the sustained ischemia on day 2 resulted in complete abolition of SWOP-mediated cytoprotective effects. These agents had no effect on the cytoprotective effects that took place during the first window of preconditioning. CONCLUSION: The cytoprotective effects of SWOP are dependent on PTP activation state and may involve upregulation of Bcl-2 expression.