Cardioprotective Function of Green Rooibos (Aspalathus linearis) Extract Supplementation in Ex Vivo Ischemic Prediabetic Rat Hearts

Diabetic patients develop ischemic heart disease and strokes more readily. Following an ischemic event, restoration of blood flow increases oxidative stress resulting in myocardial damage, termed ischemia/reperfusion injury. Aspalathus linearis (rooibos), rich in the antioxidant phenolic compound aspalathin, has been implicated as cardioprotective against ischemia/reperfusion injury with undefined mechanism in control rats. Primarily, the therapeutic potential of Afriplex green rooibos extract to prevent ischemia/reperfusion injury in cardiovascular disease-compromised rats was investigated. Additionally, Afriplex Green rooibos extract's cardioprotective signaling on metabolic markers and stress markers was determined using western blotting. Three hundred male Wistar rats received either 16-wk standard diet or high-caloric diet. During the final 6 wk, half received 60 mg/kg/day Afriplex green rooibos extract, containing 12.48% aspalathin. High-caloric diet increased body weight, body fat, fasting serum triglycerides, and homeostatic model assessment of insulin resistance - indicative of prediabetes. High-caloric diet rats had increased heart mass, infarct size, and decreased heart function. Afriplex green rooibos extract treatment for 6 wk lowered pre-ischemic heart rate, reduced infarct size, and improved heart function pre- and post-ischemia, without significantly affecting biometric parameters. Stabilized high-caloric diet hearts had decreased insulin independence via adenosine monophosphate activated kinase and increased inflammation (p38 mitogen-activated protein kinase), whereas Afriplex green rooibos extract treatment decreased insulin dependence (protein kinase B) and conferred anti-inflammatory effect. After 20 min ischemia, high-caloric diet hearts had upregulated ataxia-telangiectasia mutated kinase decreased insulin independence, and downregulated insulin dependence and glycogen synthase kinase 3 β inhibition. In contrast, Afriplex green rooibos extract supplementation downregulated insulin independence and inhibited extracellular signal-regulated kinase 1 and 2. During reperfusion, all protective signaling was decreased in high-caloric diet, while Afriplex green rooibos extract supplementation reduced oxidative stress (c-Jun N-terminal kinases 1 and 2) and inflammation. Taken together, Afriplex green rooibos extract supplementation for 6 wk preconditioned cardiovascular disease-compromised rat hearts against ischemia/reperfusion injury by lowering inflammation, oxidative stress, and heart rate.

Chaperone-Mediated Autophagy of eNOS in Myocardial Ischemia-Reperfusion Injury

[Figure: see text].

Safety and efficacy of Tirofiban in STEMI-patients

BACKGROUND

Tirofiban is recommended as bail out therapy in patients with ST-elevation myocardial infarction (STEMI). However, evidence regarding safety and efficacy of tirofiban is unclear. Tirofiban has been shown to improve ST-resolution, to decrease infarct size (IS) and to reduce incidence of major adverse cardiac and cerebrovascular events (MACCE). However, bleeding is enhanced in tirofiban treated patients. In this study, we aim to investigate efficacy and safety of Tirofiban in STEMI-patients.

METHODS

610 STEMI patients were analyzed. MACCE (death, myocardial infarction [MI], stroke) and TIMI bleeding events were registered during hospital course and 12 month follow-up.

RESULTS

Tirofiban patients were slightly younger (tirofiban 63 ± 13 years vs. control 65 ± 14 years; p = 0.04). They had higher peak-high-sensitive troponin T [Hs-TnT] (tirofiban 6561 ± 11,065 vs. control 4594 ± 11,200, p-value = 0.047) and peak-creatine kinase [CK] (tirofiban 2742 ± 5097 vs. control 1416 ± 2160, p-value < 0.0001). Percutaneous coronary intervention (PCI) was more complex in tirofiban treated patients as radiation time (tirofiban 18 ± 15 vs. control 14 ± 13; p-value = 0.02) and use of contrast agent (tirofiban 240 ± 106 vs. control 209 ± 99; p-value = 0.01) was higher in tirofiban patients. However, there were no differences in MACCE (HR 0.877, 95% CI 0.62-1.25, p = 0.47) and bleeding (major: HR 1.494, 95% CI 0.65-3.44, p = 0.34; minor: HR 1.294, 95% CI 0.67-2.52, p = 0.45).

CONCLUSION

MACCE and bleeding events were similar. However, PCI was more complex and infarcts larger in tirofiban treated patients.

Reperfusion injury in ST-segment elevation myocardial infarction: the final frontier

ST-segment elevation myocardial infarction is a major cause of morbidity and mortality worldwide. Reperfusion injury (RI) following the opening of an occluded coronary artery mitigates the effect of reperfusion by further accentuating ischemic damage and increasing infarct size. Experimental studies have shown that nearly 50% of final infarct size is attributable to RI, an elusive phenomenon that remains resistant to treatment. This review proposes a hypothesis to explain the failure of strategies that have been used in an attempt to prevent RI. This hypothesis suggests that, after a certain duration of myocardial ischemia in the affected myocardium, three phases of myocardial damage occur: reversible ischemia, irreversible ischemia, and necrosis. In the reversible ischemia phase, cellular adaptive responses remain functional, and cellular repair and thus recovery of cellular functions is possible, whereas in the irreversible ischemia phase protective maneuvers fail to confer cytoprotection. Preventive therapies for RI fail because they cannot prevent cell death once cells have entered the irreversible ischemia phase, although they may succeed in postponing cell death. Failure to salvage myocardium with irreversible ischemia in addition to postponement and change in the mode of cell death (mainly from necrosis to apoptosis) by various RI preventive strategies may be the key to understanding the failure of these strategies in the clinical setting, despite their success in the reduction of infarct size in the experimental setting. Early reperfusion before large amounts of myocardium at risk reach the stage of irreversible ischemia is the best strategy for reduction of RI-related myocardial damage.

Meta-Analysis of the Optimal Percutaneous Revascularization Strategy in Patients With Acute Myocardial Infarction, Cardiogenic Shock, and Multivessel Coronary Artery Disease

The optimal percutaneous coronary intervention (PCI) revascularization strategy in patients with multivessel (MV) coronary artery disease (CAD) who present with acute myocardial infarction (AMI) complicated by cardiogenic shock (CS) has not been systematically addressed. Accordingly, we performed a study-level meta-analysis comparing 2 PCI strategies in these patients-infarct-related artery (IRA) only versus MV revascularization. Studies including patients with AMI and MV CAD complicated with CS who received primary PCI were searched from 2000 to 2016. The primary end points were in-hospital/30-day and mid- to long-term (≥6 month) mortality. Fixed and random effects models were used for analysis. Ten studies (9 prospective and 1 retrospective) involving 6,068 patients met our inclusion criteria. IRA-only PCI was the most frequently used revascularization strategy (4,872 patients, 80%), while MV PCI was performed in 1,196 patients (20%). The MV PCI strategy was associated with higher short-term mortality compared with the IRA-only PCI strategy (odds ratio 1.41, 95% confidence interval 1.15 to 1.71, p = 0.008). There was no difference in mid- to long-term mortality between MV PCI and IRA-only strategies (odds ratio 1.02, 95% confidence interval 0.65 to 1.58, p = 0.94). In conclusion, in patients with AMI and MV CAD complicated by CS, the IRA-only PCI strategy seems to be associated with lower short-term, but not mid- to long-term mortality compared with MV PCI. This finding is different from the revascularization strategy recommended by current professional guidelines and suggests the need for dedicated randomized clinical trials.