Altered amino acid profile in patients with SARS-CoV-2 infection.
Proceedings of the National Academy of Sciences of the United States of America. 2021;(25)
Low plasma arginine bioavailability has been implicated in endothelial dysfunction and immune dysregulation. The role of arginine in COVID-19 is unknown, but could contribute to cellular damage if low. Our objective was to determine arginine bioavailability in adults and children with COVID-19 vs. healthy controls. We hypothesized that arginine bioavailability would be low in patients with COVID-19 and multisystem inflammatory syndrome in children (MIS-C). We conducted a prospective observational study of three patient cohorts; arginine bioavailability was determined in asymptomatic healthy controls, adults hospitalized with COVID-19, and hospitalized children/adolescents <21 y old with COVID-19, MIS-C, or asymptomatic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection identified on admission screen. Mean patient plasma amino acids were compared to controls using the Student's t test. Arginine-to-ornithine ratio, a biomarker of arginase activity, and global arginine bioavailability ratio (GABR, arginine/[ornithine+citrulline]) were assessed in all three groups. A total of 80 patients were included (28 controls, 32 adults with COVID-19, and 20 pediatric patients with COVID-19/MIS-C). Mean plasma arginine and arginine bioavailability ratios were lower among adult and pediatric patients with COVID-19/MIS-C compared to controls. There was no difference between arginine bioavailability in children with COVID-19 vs. MIS-C. Adults and children with COVID-19 and MIS-C in our cohort had low arginine bioavailability compared to healthy adult controls. This may contribute to immune dysregulation and endothelial dysfunction in COVID-19. Low arginine-to-ornithine ratio in patients with COVID-19 or MIS-C suggests an elevation of arginase activity. Further study is merited to explore the role of arginine dysregulation in COVID-19.
COVID-19 and Hartnup disease: an affair of intestinal amino acid malabsorption.
Eating and weight disorders : EWD. 2021;(5):1647-1651
Since the outbreak of COVID-19, clinicians have tried every effort to fight the disease, and multiple drugs have been proposed. However, no proven effective therapies currently exist, and different clinical phenotypes complicate the situation. In clinical practice, many severe or critically ill COVID-19 patients developed gastrointestinal (GI) disturbances, including vomiting, diarrhoea, or abdominal pain, even in the absence of cough and dyspnea. Understanding the mechanism of GI disturbances is warranted for exploring better clinical care for COVID-19 patients. With evidence collected from clinical studies on COVID-19 and basic research on a rare genetic disease (i.e., Hartnup disorder), we put forward a novel hypothesis to elaborate an effective nutritional therapy. We hypothesize that SARS-CoV-2 spike protein, binding to intestinal angiotensin-converting enzyme 2, negatively regulates the absorption of neutral amino acids, and this could explain not only the GI, but also systemic disturbances in COVID-19. Amino acid supplements could be recommended.Level of evidence No level of evidence: Hypothesis article.
Effects of Micronutrients or Conditional Amino Acids on COVID-19-Related Outcomes: An Evidence Analysis Center Scoping Review.
Journal of the Academy of Nutrition and Dietetics. 2021;(7):1354-1363
Recent narrative reviews have described the potential efficacy of providing individuals infected with coronavirus disease 2019 (COVID-19) with additional micronutrients to reduce disease severity. Although there are compelling reasons why providing additional micronutrients or conditional amino acids may affect COVID-19-related outcomes, evidence is lacking. The objective of this scoping review is to explore and describe the literature examining the effect of providing additional micronutrients or conditional amino acids (glutamine, arginine) in adults with conditions or infections similar to COVID-19 infection on COVID-19-related health outcomes. A literature search of the MEDLINE database and hand search of Cochrane Database of systematic reviews retrieved 1,423 unique studies, and 8 studies were included in this scoping review. Four studies examined a target population with ventilator-related pneumonia and acute respiratory distress syndrome, and the other 4 studies included patients who were at risk for ventilator-associated pneumonia. Interventions included intravenous ascorbic acid, intramuscular cholecalciferol, enteral and intramuscular vitamin E, enteral zinc sulfate, and oral and parenteral glutamine. In 6 of the 8 included studies, baseline status of the nutrient of interest was not reported and, thus, it is uncertain how outcomes may vary in the context of nutrient deficiency or insufficiency compared with sufficiency. In the absence of direct evidence examining efficacy of providing additional micronutrients or conditional amino acids to standard care, registered dietitian nutritionists must rely on clinical expertise and indirect evidence to guide medical nutrition therapy for patients infected with COVID-19.