No abstract

Growing evidence has shown that acute exercise impairs erythrocyte membrane structure and function as a consequence of increased physical and chemical stress. Erythrocyte-synthesized nitric oxide (NO) is known to modulate membrane fluidity, and its bioavailability depends on the balance between its production and scavenging by reactive oxygen species. Here, we investigated whether a maximal exercise test could affect erythrocyte NO bioavailability and oxidative stress. Twelve men (26±4 years old, V̇O2peak 44.1±4.3 mL·kg-1·min-1) performed a treadmill maximal cardiopulmonary exercise test. Blood was collected at rest and immediately after exercise for erythrocytes isolation. Maximal exercise caused an increase in erythrocytes count, haemoglobin and haematocrit levels. There was no change in L-arginine influx into erythrocytes after exercise. Yet, nitric oxide synthase activity, and thus, NO production, was increased after maximal test, as well cyclic GMP levels. In relation to biomarkers of oxidative stress, maximal test resulted in increased levels of lipid peroxidation, and diminished superoxide dismutase activity. Neither glutathione peroxidase nor catalase activity was affected by maximal test. Our findings demonstrate that the increased erythrocyte membrane rigidity caused by an acute bout of exercise may be caused, in part, by an increased lipid oxidative damage caused by ROS produced exogenously.

Six months of aerobic exercise training performed with high frequency is preferable to low frequency aiming endothelium microvascular function increases in patients with coronary artery disease. The mechanisms involved in this response are unclear and warrant additional research.

Coronavirus disease 2019 (COVID-19) is a viral pneumonia that can lead to acute respiratory distress syndrome (ARDS). Until the commercialization of a vaccine, pharmacological treatment still represents an important strategy to fight against the ongoing pandemic. Glucocorticoids (GC) were widely used in the past coronavirus pandemics and have been used against the coronavirus 2 severe acute respiratory syndrome (SARS-CoV-2). This article aimed to review the studies that described the treatment with GC in COVID-19 patients. Randomized or nonrandomized clinical trials and retrospective or prospective-controlled longitudinal studies were screened for this systematic review. Studies in English, Portuguese, and Spanish published since 2019, with participants of any clinical status, geographic location, age, and sex were included. The most significant interest was related to the length of stay, radiological profile changes, viremia, and mortality. The research was done electronically on the Pubmed database using the following terms: "corticosteroids", "glucocorticoids", "dexamethasone", "methylprednisolone", "COVID-19", "SARS-CoV-2", "ADRS". We identified 6332 publications, and at the end, 14 retrospective observational studies that met all the inclusion criteria were selected. These studies included only patients infected with SARS-CoV-2 confirmed by RT-PCR, involving 2,713 participants. The results showed great heterogeneity in their designs and results, which precludes a reliable conclusion on the use of GCs in the treatment of COVID-19.

This study compared macro‐ and microvascular endothelial function and redox status in active vs inactive HIV‐infected patients (HIVP) under antiretroviral therapy. Using a cross‐sectional design, macro‐ and microvascular reactivity, systemic microvascular density, and oxidative stress were compared between 19 HIVP (53.1 ± 6.1 year) enrolled in a multimodal training program (aerobic, strength and flexibility exercises) for at least 12 months (60‐minutes sessions performed 3 times/wk with moderate intensity) vs 25 sedentary HIVP (51.2 ± 6.3 year). Forearm blood flow during reactive hyperemia (521.7 ± 241.9 vs 361.4% ± 125.0%; P = 0.04) and systemic microvascular density (120.8 ± 21.1 vs 105.6 ± 25.0 capillaries/mm2; P = 0.03) was greater in active than inactive patients. No significant difference between groups was detected for endothelium‐dependent and independent skin microvascular vasodilation (P > 0.05). As for redox status, carbonyl groups (P = 0.22), lipid peroxidation (P = 0.86), catalase activity (P = 0.99), and nitric oxide levels (P = 0.72) were similar across groups. However, superoxide dismutase activity was greater in active vs inactive HIVP (0.118 ± 0.013 vs 0.111 ± 0.007 U/mL; P = 0.05). Immune function reflected by total T CD4 and T CD8 counts (cell/mm3) did not differ between active and inactive groups (P > 0.82). In conclusion, physically active HIVP exhibited similar immune function, but greater macrovascular reactivity, systemic microvascular density, and superoxide dismutase activity than inactive patients of similar age.