CO Improves Mitochondrial Population Figure 1. Effects of CORM-3 on high-fat-induced cardiac dysfunction. (A) Left Ventricular Developed Pressure (LVDP) of hearts isolated from normal diet (ND) or high-fat diet (HFD) mice injected twice with iCORM-3 (10 mg.kg21, intraperitoneally, studied 24 hours after the second injection) or CORM-3 (10 mg.kg21, intraperitoneally, studied 24, 48 or 72 hours after the second injection, or 24 hours after the fifth injection (x5); see Materials and Methods). (B) LVDP first derivatives 6dP/dt and (C) ratio (LVDP x Heart Rate)/MVO2 (see Materials and Methods) obtained from ND, ND + CORM-3, HFD and CORM-3–treated HFD mouse hearts. Evaluation was performed 24 hours after the second injection. (D) Maximal oxygen uptake (VO2) increase of mice subjected to exercise stress test. Data represent means 6 SEM. n = 5–8 in each group. White bars = ND; vertically hatched bars = ND + CORM-3; black bars = HFD; crosshatched bars = HFD + CORM-3. * p,0.05 vs. ND, { p,0.05 vs. HFD. doi:10.1371/journal.pone.0041836.g001 Intrinsic contractile function was evaluated on isolated hearts. Left ventricular developed pressure (LVDP) was significantly decreased in HFD mice as compared with ND animals (Table S2, Figure 1A). There were no differences in the coronary perfusion pressure (CPP) between groups (Table S2). CORM-3 Ameliorated Cardiac Function in Mice with Metabolic Syndrome Compared to HFD, injection of CORM-3 (10 mg.kg21) for 5 consecutive days did not improve cardiac function (Figure 1A). Next, we injected mice twice with CORM-3 (see Materials and Methods) and heart function was evaluated 24, 48 or 72 hours after the last injection. Compared to untreated HFD mice, LVDP was greatly improved in hearts isolated from HFD mice that were studied 24 hours after the last injection of CORM-3 (Figure 1A). Beneficial effect of CORM-3 on cardiac function lessened overtime (Figure 1A). iCORM-3 injections (see Materials and Methods) did not alter LVDP neither in ND mice, nor in HFD mice (Figure 1A). Consequently, we performed all subsequent experiments in CORM-3 -treated animals 24 hours after the last injection (HFD + CORM-3). In addition to LVDP, CORM-3 also ameliorated dP/ dt values compared to HFD hearts (Figure 1B). Ratio (LVDP 6 HR) to MVO2, a proxy measure for cardiac efficiency (see Materials and Methods), was reduced in the HFD hearts and rescued by CORM-3 (Figure 1C). CORM-3 injections in ND mice had no effects (Figure 1). Cardiac output reduction may limit the rate of oxygen exchange to the tissues and would in turn restrict performance to exercise. Thus, we subjected mice to a maximal physical exercise and measured their maximal oxygen consumption (VO2) increase as a surrogate of the cardiovascular adaptation in vivo. The increase in VO2 consecutive to exercise was reduced in HFD mice as compared with ND littermates (Figure 1D). However, VO2 increase was significantly improved in HFD + CORM-3 group compared to HFD mice (Figure 1D). CORM-3 did not Reverse Metabolic Syndrome but Improved Maximal Aerobic Capacity As high-fat diet led to metabolic syndrome and cardiovascular dysfunction, we tested whether the beneficial effects mediated by CORM-3 were related to changes in metabolic parameters. Neither glucose tolerance (Figure 2A) nor insulin resistance (Figure 2B) was restored by CORM-3. Similarly, CORM-3 was unable to reverse plasma cholesterol (Figure 2C) and true triglyceride (Figure 2D) elevations triggered by the high-fat regimen. PLoS ONE | www.plosone.org 4 August 2012 | Volume 7 | Issue 8 | e41836