Skeletal Muscle Damage in COVID-19: A Call for Action

Abstract

Both laboratory investigations and body composition quantification measures (e.g., computed tomography, CT) portray muscle loss in symptomatic Coronavirus disease 2019 (COVID-19) patients. Muscle loss is associated with a poor prognosis of the disease. The exact mechanism of muscle damage in COVID-19 patients, as well as the long-term consequences of muscle injury in disease survivors, are unclear. The current review briefly summarizes the literature for mechanisms, assessment measures, and interventions relevant to skeletal muscle insult in COVID-19 patients. Muscle injury is likely to be attributed to the cytokine storm, disease severity, malnutrition, prolonged physical inactivity during intensive care unit (ICU) stays, mechanical ventilation, and myotoxic drugs (e.g., dexamethasone). It has been assessed by imaging and non-imaging techniques (e.g., CT and electromyography), physical performance tests (e.g., six-minute walk test), anthropometric measures (e.g., calf circumference), and biomarkers of muscle dystrophy (e.g., creatine kinase). Interventions directed toward minimizing muscle loss among COVID-19 patients are lacking. However, limited evidence shows that respiratory rehabilitation improves respiratory function, muscle strength, quality of life, and anxiety symptoms in recovering older COVID-19 patients. Neuromuscular electrical stimulation may restore muscle condition in ICU-admitted patients, albeit empirical evidence is needed. Given the contribution of malnutrition to disease severity and muscle damage, providing proper nutritional management for emaciated patients may be one of the key issues to achieve a better prognosis and prevent the after-effects of the disease. Considerable attention to longer-term consequences of muscle injury in recovering COVID-19 patients is necessary.

Physical Frailty/Sarcopenia as a Key Predisposing Factor to Coronavirus Disease 2019 (COVID-19) and Its Complications in Older Adults

“…Poor muscle mass and strength negatively correlate with the respiratory muscle strength, which is reflected by maximum expiratory pressure [65]. Therefore, sarcopenia may exacerbate pulmonary function in older COVID-19 patients [36,66]. Furthermore, longitudinal data denote that low skeletal mass and sarcopenic obesity are associated with an increased risk for renal injury-indicated by developing albuminuria [67].…”

“…Malnutrition either protein-energy or micronutrient deficiency disintegrates the immune system and triggers chronic inflammation [66,77]. Therefore, emaciated individuals including nutritionally frail older adults are highly vulnerable to COVID-19 and are more likely to develop severe adverse effects of the disease [23].…”

“…Moreover, frailty is a key predictive factor for poor prognosis and mortality in patients with COVID-19 [28,29]. It is suggested that the use of frailty as a predictor of poor prognosis can be more informative than the use of age or comorbidities for this purpose because frailty in COVID-19 has been also noted in young individuals [31,32,36,66]. In this regard, elders with higher Frailty Index (FI) are at high risk for intensive care unit (ICU) admission [31].…”

The Effects of Royal Jelly Acid, 10-Hydroxy-trans-2-decenoic Acid, on Neuroinflammation and Oxidative Stress in Astrocytes Stimulated with Lipopolysaccharide and Hydrogen Peroxide

“…Recovering patients experience persistent symptoms several months following hospital/ICU discharge [3,4]: depression (in up to 30% of patients) [5], sleep disorders (in up to 100% of patients), post-traumatic stress disorders (in up to 32% of patients) [3], and mild to moderate cognitive impairment (in up to 81% of patients) in patients who were cognitively intact before contracting COVID-19 [6,7]. Steroids are reported to foster tissue damage in COVID-19 patients [8]; mania and psychosis induced by steroids have been reported in a few COVID-19 patients [3]. In addition, the cytokine storm associated with COVID-19 is to blame for the inflammatory reactions and tissue damage that accompany COVID-19 infection [8][9][10].…”

“…Steroids are reported to foster tissue damage in COVID-19 patients [8]; mania and psychosis induced by steroids have been reported in a few COVID-19 patients [3]. In addition, the cytokine storm associated with COVID-19 is to blame for the inflammatory reactions and tissue damage that accompany COVID-19 infection [8][9][10]. Although presence of the virus causing COVID-19 in neurons does not cause neurodegeneration [1], evidence supports cytokine involvement in COVID-19-related neuropsychiatric disorders [1,7].…”