The dysfunction of the renin-angiotensin system (RAS) has been observed in coronavirus infection disease patients, but whether RAS inhibitors, such as angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin II type 1 receptor blockers (ARBs), are associated with clinical outcomes remains unknown. COVID-19 patients with hypertension were enrolled to evaluate the effect of RAS inhibitors. We observed that patients receiving ACEI or ARB therapy had a lower rate of severe diseases and a trend toward a lower level of IL-6 in peripheral blood. In addition, ACEI or ARB therapy increased CD3 and CD8 T cell counts in peripheral blood and decreased the peak viral load compared to other antihypertensive drugs. This evidence supports the benefit of using ACEIs or ARBs to potentially contribute to the improvement of clinical outcomes of COVID-19 patients with hypertension.

Background: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) could cause virulent infection leading to Corona Virus Disease 2019 (COVID-19)-related pneumonia as well as multiple organ injuries. Hypothesis: COVID-19 infection may result in cardiovascular manifestations leading to worse clinical outcome. Methods: Fifty four severe and critical patients with confirmed COVID-19 were enrolled. Risk factors predicting the severity of COVID-19 were analyzed.Results: Of the 54 patients (56.1 ± 13.5 years old, 66.7% male) with COVID-19, 39 were diagnosed as severe and 15 as critical cases. The occurrence of diabetes, the level of D-dimer, inflammatory and cardiac markers in critical cases were significantly higher. Troponin I (TnI) elevation occurred in 42.6% of all the severe and critical patients. Three patients experienced hypotension at admission and were all diagnosed as critical cases consequently. Hypotension was found in one severe case and seven critical cases during hospitalization. Sinus tachycardia is the most common type of arrythmia and was observed in 23 severe patients and all the critical patients.Atrioventricular block and ventricular tachycardia were observed in critical patients at end stage while bradycardia and atrial fibrillation were less common. Mild pericardial effusion was observed in one severe case and five critical cases. Three critical cases suffered new onset of heart failure. Hypotension during treatment, severe myocardial injury and pericardial effusion were independent risk factors predicting the critical status of COVID-19 infection.

The peroxisome proliferator-activated receptor γ (PPARγ) coactivator-1s (PGC-1s) can induce the expression of several downstream genes that play pivotal roles in the regulation of mitochondrial biogenesis and metabolism in the heart. Moreover, PGC-1 signaling pathways have also been reported to play a critical role in cardioprotection. Given the significance of PGC-1 coactivators, we summarize the current literature on the molecular mechanisms and roles of PGC-1s in cardiac metabolism. Thus, in this review, we first introduce the basic knowledge regarding PGC-1 signaling pathways. We then discuss their roles in heart metabolism. Moreover, we describe several significant treatments that target the PGC-1 signaling pathway. This review presents the significant roles of PGC-1s in cardiac metabolism and may contribute to the promotion of PGC-1 signaling pathway as a novel therapeutic target.

It has been demonstrated that the anti-oxidative and cardioprotective effects of melatonin are, at least in part, mediated by its membrane receptors. However, the direct downstream signaling remains unknown. We previously found that melatonin ameliorated myocardial ischemia-reperfusion (MI/R) injury in diabetic animals, although the underlying mechanisms are also incompletely understood. This study was designed to determine the role of melatonin membrane receptors in melatonin's cardioprotective actions against diabetic MI/R injury with a focus on cGMP and its downstream effector PKG. Streptozotocin-induced diabetic Sprague-Dawley rats and high-glucose medium-incubated H9c2 cardiomyoblasts were utilized to determine the effects of melatonin against MI/R injury. Melatonin treatment preserved cardiac function and reduced oxidative damage and apoptosis. Additionally, melatonin increased intracellular cGMP level, PKGIα expression, p-VASP/VASP ratio and further modulated myocardial Nrf-2-HO-1 and MAPK signaling. However, these effects were blunted by KT5823 (a selective inhibitor of PKG) or PKGIα siRNA except that intracellular cGMP level did not changed significantly. Additionally, our in vitro study showed that luzindole (a nonselective melatonin membrane receptor antagonist) or 4P-PDOT (a selective MT receptor antagonist) not only blocked the cytoprotective effect of melatonin, but also attenuated the stimulatory effect of melatonin on cGMP-PKGIα signaling and its modulatory effect on Nrf-2-HO-1 and MAPK signaling. This study showed that melatonin ameliorated diabetic MI/R injury by modulating Nrf-2-HO-1 and MAPK signaling, thus reducing myocardial apoptosis and oxidative stress and preserving cardiac function. Importantly, melatonin membrane receptors (especially MT receptor)-dependent cGMP-PKGIα signaling played a critical role in this process.