This study was the first to investigate the vascular implications of contracting SARS-CoV-2 among young, otherwise healthy adults. Using a cross-sectional design, this study assessed vascular function 3–4 wk after young adults tested positive for SARS-CoV-2. The main findings from this study were a strikingly lower vascular function and a higher arterial stiffness compared with healthy controls. Together, these results suggest rampant vascular effects seen weeks after contracting SARS-CoV-2 in young adults.

 The impact of SARS-CoV-2 infection on autonomic and cardiovascular function in otherwise healthy individuals is unknown. We show for the first time that young adults recovering from SARS-CoV-2 have elevated resting sympathetic activity, but similar heart rate and blood pressure, compared with control subjects. Survivors of SARS-CoV-2 also exhibit suppressed sympathetic nerve activity and pain perception during a cold pressor test compared with healthy controls.  Further, these individuals display higher sympathetic nerve activity throughout an orthostatic challenge, as well as an exaggerated heart rate response to orthostasis. If similar autonomic dysregulation, like that found here in young individuals, is present in older adults following SARS-CoV-2 infection, there may be substantial adverse implications for cardiovascular health.

Contracting severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been observed to cause decrements in vascular function of young adults. However, less is known about the impact of SARS-CoV-2 on arterial stiffness and structure, which might have additional implications for cardiovascular health. The purpose of this study was to assess the carotid artery stiffness and structure using ultrasound and the aortic augmentation index (AIx) using applanation tonometry in young adults after they tested positive for SARS-CoV-2. We hypothesized that carotid artery stiffness, carotid intima-media thickness (cIMT) and aortic AIx would be elevated in young adults with SARS-CoV-2 compared with healthy young adults. We evaluated 15 young adults (six male and nine female; 20 ± 1 years of age; body mass index, 24 ± 3 kg m −2 ) 3-4 weeks after a positive SARS-CoV-2 test result compared with young healthy adults (five male and 10 female; 23 ± 1 years of age; body mass index, 22 ± 2 kg m −2 ) who were evaluated before the coronavirus 2019 pandemic. Carotid stiffness, Young's modulus and cIMT were assessed using ultrasound, whereas aortic AIx and aortic AIx standardized to 75 beats min −1 (AIx@HR75) were assessed from carotid pulse wave analysis using SphygmoCor. Group differences were observed for carotid stiffness (control, 5 ± 1 m s −1 ; SARS-CoV-2, 6 ± 1 m s −1 ), Young's modulus (control, 396 ± 120 kPa; SARS-CoV-2, 576 ± 224 kPa), aortic AIx (control, 3 ± 13%; SARS-CoV-2, 13 ± 9%) and aortic AIx@HR75 (control, −3 ± 16%; SARS-CoV-2, 10 ± 7%; P < 0.05). However, cIMT was similar between groups (control, 0.42 ± 0.06 mm; SARS-CoV-2, 0.44 ± 0.08 mm; P > 0.05). This cross-sectional analysis revealed higher carotid artery stiffness and aortic stiffness among young adults with SARS-CoV-2.These results provide further evidence of cardiovascular impairments among young adults recovering from SARS-CoV-2 infection, which should be considered for cardiovascular complications associated with SARS-CoV-2.

Total knee arthroplasty (TKA) utilizes a tourniquet to reduce blood loss, maintain a clear surgical “bloodless” field, and to ensure proper bone-implant cementing. In 2007, over 600,000 TKAs were performed in the United States, and this number is projected to increase to 3.48 million procedures performed annually by 2030. The acute effects of tourniquet-induced ischemia-reperfusion (I/R) on human skeletal muscle cells are poorly understood and require critical investigation, as muscle atrophy following this surgery is rapid and represents the most significant clinical barrier to long-term normalization of physical function. To determine the acute effects of I/R on skeletal muscle cells, biopsies were obtained at baseline, maximal ischemia (prior to tourniquet release), and reperfusion (following tourniquet release). Quadriceps volume was determined before and 2 wk post-TKA by MRI. We measured a 36% decrease in phosphorylation of Akt Ser473during ischemia and 37% during reperfusion ( P < 0.05). 4E-BP1 Thr37/46phosphorylation decreased 29% during ischemia and 22% during reperfusion ( P < 0.05). eEF2 Thr56phosphorylation increased 25% during ischemia and 43% during reperfusion ( P < 0.05). Quadriceps volume decreased 12% in the TKA leg ( P < 0.05) and tended to decrease (6%) in the contralateral leg ( P = 0.1). These data suggest cap-dependent translation initiation, and elongation may be inhibited during and after TKA surgery. We propose that cap-dependent translational events occurring during surgery may precipitate postoperative changes in muscle cells that contribute to the etiology of muscle atrophy following TKA.

Common cyclooxygenase (COX)-inhibiting drugs enhance resistance exercise induced muscle mass and strength gains in older individuals. The purpose of this investigation was to determine whether the underlying mechanism regulating this effect was specific to Type I or Type II muscle fibers, which have different contractile and metabolic profiles. Muscle biopsies (vastus lateralis) were obtained before and after 12 weeks of knee-extensor resistance exercise (3 days/week) from healthy older men who consumed either a placebo (n = 8; 64±2 years) or COX inhibitor (acetaminophen, 4 gram/day; n = 7; 64±1 years) in double-blind fashion. Muscle samples were examined for Type I and II fiber cross-sectional area, capillarization, and metabolic enzyme activities (glycogen phosphorylase, citrate synthase, β-hydroxyacyl-CoA-dehydrogenase). Type I fiber size did not change with training in the placebo group (304±590 μm(2)) but increased 28% in the COX inhibitor group (1,388±760 μm(2), p < .1). Type II fiber size increased 26% in the placebo group (1,432±499 μm(2), p < .05) and 37% in the COX inhibitor group (1,825±400 μm(2), p < .05). Muscle capillarization and enzyme activity were generally maintained in the placebo group. However, capillary to fiber ratio increased 24% (p < .1) and citrate synthase activity increased 18% (p < .05) in the COX inhibitor group. COX inhibitor consumption during resistance exercise in older individuals enhances myocellular growth, and this effect is more pronounced in Type I muscle fibers.