Calpain-mediated TnI proteolysis can be dissociated from stunning and arises from elevations in preload rather than ischemia. This raises the possibility that ongoing preload-induced TnI degradation could impair myocardial function long-term.

Sodium sulfide is efficacious in reducing apoptosis in response to I/R injury. Along with its known effects on reducing necrosis, sulfide's effects on apoptosis may partially contribute to providing myocardial protection. Exogenous sulfide may have therapeutic utility in clinical settings in which I/R injury is encountered.

Introduction Hydrogen sulfide (H2S) is produced endogenously in response to myocardial ischemia and thought to be cardioprotective. The mechanism underlying this protection has yet to be fully elucidated, but may be related sulfide’s ability to limit inflammation. This study investigates the cardioprotection provided by exogenous H2S, and its potential anti-inflammatory mechanism of action. Methods The mid-LAD coronary artery in 14 Yorkshire swine was acutely occluded for 60 minutes, followed by reperfusion for 120 minutes. Controls(7) received placebo, and treatment animals(7) received sulfide 10 minutes prior to and throughout reperfusion. Hemodynamic and functional measurements were obtained. Evans blue and TTC staining identified the area-at-risk and infarction. Coronary microvascular reactivity was assessed. Tissue was assayed for myeloperoxidase activity and pro-inflammatory cytokines. Results Pre-I/R hemodynamics were similar between groups, whereas post-I/R mean arterial pressure (mmHg) was reduced by 28.7±5.0 in controls vs. 6.7±6.2 in treatment animals (p=0.03). +LV dP/dt (mmHg/sec) was reduced by 1325±455 in controls vs. 416±207 in treatment animals (p=0.002). Segmental shortening in the area-at-risk was better in treatment animals. Infarct size (% of area-at-risk) in controls was 41.0±7.8% vs. 21.2±2.5% in the treated group (p=0.036). Tissue levels of IL-6, IL-8, and TNFα and MPO activity decreased in the treatment group. Treated animals demonstrated improved microvascular reactivity. Conclusions Therapeutic sulfide provides protection in response to I/R injury, improving myocardial function, reducing infarct size, and improving coronary microvascular reactivity, potentially through its anti-inflammatory properties. Exogenous sulfide may have therapeutic utility in clinical settings in which I/R injury is encountered.

Background— Resveratrol may provide protection against coronary artery disease. We hypothesized that supplemental resveratrol will improve cardiac perfusion in the ischemic territory of swine with hypercholesterolemia and chronic myocardial ischemia. Methods and Results— Yorkshire swine were fed either a normal diet (control, n=7), a hypercholesterolemic diet (HCC, n=7), or a hypercholesterolemic diet with supplemental resveratrol (100 mg/kg/d orally, HCRV, n=7). Four weeks later, an ameroid constrictor was placed on the left circumflex artery. Animals underwent cardiac MRI and coronary angiography 7 weeks later before euthanasia and tissue harvest. Total cholesterol was lowered about 30% in HCRV animals ( P <0.001). Regional wall motion analysis demonstrated a significant decrease in inferolateral function from baseline to 7 weeks in HCC swine ( P =0.04). There was no significant change in regional function in HCRV swine from baseline to 7 weeks ( P =0.32). Tissue blood flow during stress was 2.8-fold greater in HCRV swine when compared with HCC swine ( P =0.04). Endothelium-dependent microvascular relaxation response to Substance P was diminished in HCC swine, which was rescued by resveratrol treatment ( P =0.004). Capillary density (PECAM-1 staining) demonstrated fewer capillaries in both HCC and HCRV swine versus control swine ( P =0.02). Immunoblot analysis demonstrated significantly greater expression in HCRV versus HCC swine of the following markers of angiogenesis: VEGF ( P =0.002), peNOS (ser1177) ( P =0.04), NFkB ( P =0.004), and pAkt (thr308) ( P =0.001). Conclusions— Supplemental resveratrol attenuates regional wall motion abnormalities, improves myocardial perfusion in the collateral dependent region, preserves endothelium-dependent coronary vessel function, and upregulates markers of angiogenesis associated with the VEGF signaling pathway.