Ranolazine reduces Ca2+ overload and oxidative stress and improves mitochondrial integrity to protect against ischemia reperfusion injury in isolated hearts

Abstract

Ranolazine is a clinically approved drug for treating cardiac ventricular dysrhythmias and angina. Its mechanism(s) of protection is not clearly understood but evidence points to blocking the late Na+ current that arises during ischemia, blocking mitochondrial complex I activity, or modulating mitochondrial metabolism. Here we tested the effect of ranolazine treatment before ischemia at the mitochondrial level in intact isolated hearts and in mitochondria isolated from hearts at different times of reperfusion. Left ventricular (LV) pressure (LVP), coronary flow (CF), and O2 metabolism were measured in guinea pig isolated hearts perfused with Krebs-Ringer’s solution; mitochondrial (m) O2•−, Ca2+, NADH/FAD (redox state), and cytosolic (c) Ca2+ were assessed on-line in the LV free wall by fluorescence spectrophotometry. Ranolazine (5 µM), infused for 1 min just before 30 min of global ischemia, itself did not change O2•−, cCa2+, mCa2+ or redox state. During late ischemia and reperfusion (IR) O2•− emission and m[Ca2+] increased less in the ranolazine group vs. the control group. Ranolazine decreased c[Ca2+] only during ischemia while NADH and FAD were not different during IR in the ranolazine vs. control groups. Throughout reperfusion LVP and CF were higher, and ventricular fibrillation was less frequent. Infarct size was smaller in the ranolazine group than the control group. Mitochondria isolated from ranolazine-treated hearts had mild resistance to permeability transition pore (mPTP) opening and less cytochrome c release than control hearts. Ranolazine may provide functional protection of the heart during IR injury by reducing cCa2+ and mCa2+ loading secondary to its effect to block the late Na+ current. Subsequently it indirectly reduces O2•− emission, preserves bioenergetics, delays mPTP opening, and restricts loss of cytochrome c, thereby reducing necrosis and apoptosis.

Sarcoendoplasmic Reticulum Ca2+ ATPase. A Critical Target in Chlorine Inhalation–Induced Cardiotoxicity

“…Others previously found preservation of intracellular ATP content and mitochondrial function by ranolazine during protection against ischemiareperfusion (20). Because ranolazine may impact other pathways, we also used istaroxime, a more specific SERCA activator (56).…”

“…We have previously shown chlorine-induced apoptotic cell death in primary rat cardiomyocytes (10). Ranolazine can protect against calcium overload and preserve mitochondrial integrity in an ischemia-reperfusion model of isolated guinea pig heart (20). Because ranolazine preserves SERCA function, we determined its effect on mitochondrial function.…”

Is the Pleotropic Effect of Ranolazine is Due to its Antioxidant Action

“…In a study published by Tocchetti CG [4] et al in animal experiments it was shown that Ranolazine protects against experimental doxorubicin cardio toxicity. Such protection is accompanied by a reduction in oxidative stress [5,6] suggesting that INa modulates cardiac redox [7] balance. In our study we used malonaldehyde [8] as on oxidative stress maker which was shown to decreased from baseline in cases in comparison to controls.…”

Genetically determined mitochondrial preservation and cardioprotection against myocardial ischemia-reperfusion injury in a consomic rat model

“…Our methods have been described in detail previously (1,12,(21)(22)(23). Unless otherwise indicated, all drugs were purchased from Sigma (St. Louis, MO).…”

“…Hearts were immediately removed from the setup and immersed in 4°C cold isolation buffer containing (in mM) 200 mannitol, 50 sucrose, 5 KH 2PO4, 5 3-(N-morpholino)propanesulfonic acid (MOPS), and 1 EGTA, with 0.1% bovine serum albumin (BSA), pH 7.15 (adjusted with KOH) (1,21). The atria were discarded, and the ventricles were minced into 1 mm 3 pieces.…”