COVID-19 Causes Ferroptosis and Oxidative Stress in Human Endothelial Cells.

Oxidative stress and endothelial dysfunction have been shown to play crucial roles in the pathophysiology of COVID-19 (coronavirus disease 2019). On these grounds, we sought to investigate the impact of COVID-19 on lipid peroxidation and ferroptosis in human endothelial cells. We hypothesized that oxidative stress and lipid peroxidation induced by COVID-19 in endothelial cells could be linked to the disease outcome. Thus, we collected serum from COVID-19 patients on hospital admission, and we incubated these sera with human endothelial cells, comparing the effects on the generation of reactive oxygen species (ROS) and lipid peroxidation between patients who survived and patients who did not survive. We found that the serum from non-survivors significantly increased lipid peroxidation. Moreover, serum from non-survivors markedly regulated the expression levels of the main markers of ferroptosis, including GPX4, SLC7A11, FTH1, and SAT1, a response that was rescued by silencing TNFR1 on endothelial cells. Taken together, our data indicate that serum from patients who did not survive COVID-19 triggers lipid peroxidation in human endothelial cells.

miR-142 Targets TIM-1 in Human Endothelial Cells: Potential Implications for Stroke, COVID-19, Zika, Ebola, Dengue, and Other Viral Infections.

T-cell immunoglobulin and mucin domain 1 (TIM-1) has been recently identified as one of the factors involved in the internalization of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in human cells, in addition to angiotensin-converting enzyme 2 (ACE2), transmembrane serine protease 2 (TMPRSS2), neuropilin-1, and others. We hypothesized that specific microRNAs could target TIM-1, with potential implications for the management of patients suffering from coronavirus disease 2019 (COVID-19). By combining bioinformatic analyses and functional assays, we identified miR-142 as a specific regulator of TIM-1 transcription. Since TIM-1 has been implicated in the regulation of endothelial function at the level of the blood-brain barrier (BBB) and its levels have been shown to be associated with stroke and cerebral ischemia-reperfusion injury, we validated miR-142 as a functional modulator of TIM-1 in human brain microvascular endothelial cells (hBMECs). Taken together, our results indicate that miR-142 targets TIM-1, representing a novel strategy against cerebrovascular disorders, as well as systemic complications of SARS-CoV-2 and other viral infections.

L-Arginine Enhances the Effects of Cardiac Rehabilitation on Physical Performance: New Insights for Managing Cardiovascular Patients During the COVID-19 Pandemic.

Cardiac rehabilitation (CR) following acute myocardial infarction (AMI) improves physical capacities and decreases hospitalizations and cardiovascular mortality. L-arginine is the substrate used by nitric oxide (NO) synthase to generate NO and it has been shown to exert its beneficial effects on endothelium driving vasodilatation, reducing inflammation, and ameliorating physical function. We hypothesized that L-arginine could enhance physical capacities in patients who underwent CR after AMI. We designed a study aimed to assess the effects of L-arginine administration on the physical capacity of patients who underwent coronary revascularization after AMI. The trial was carried out amid the COVID-19 pandemic. Patients were assigned, with a 2:1 ratio, to add to their standard therapy one bottle containing 1.66 g of L-arginine or one bottle of identical aspect apart from not containing L-arginine, twice a day orally for 3 weeks. Patients performed a 6-minute walking test (6MWT), and their Borg modified 0-10 rating of perceived exertion (BRPE) was assessed before starting and at the end of the treatment. Seventy-five patients receiving L-arginine, and 35 receiving placebo successfully completed the study. The 6MWT distance increased significantly in the L-arginine group compared with both baseline and placebo (P < 0.0001). Additionally, we observed a significant improvement in the BRPE in patients treated with L-arginine but not in the placebo group. Taken together, our data indicate that L-arginine potentiates the response to CR independently of age, sex, baseline functional capacity, and comorbid conditions. SIGNIFICANCE STATEMENT: This study shows for the first time that oral supplementation of L-arginine potentiates the response to cardiac rehabilitation after myocardial infarction and cardiac revascularization. Indeed, we observed a significant improvement in two fundamental parameters, namely, the 6-minute walking test and the Borg modified 0-10 rating of perceived exertion. Strikingly, the beneficial effects of L-arginine were independent of age, sex, comorbid conditions, and baseline functional capacity.

l-Arginine and COVID-19: An Update.

l-Arginine is involved in many different biological processes and recent reports indicate that it could also play a crucial role in the coronavirus disease 2019 (COVID-19), caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Herein, we present an updated systematic overview of the current evidence on the functional contribution of L-Arginine in COVID-19, describing its actions on endothelial cells and the immune system and discussing its potential as a therapeutic tool, emerged from recent clinical experimentations.