Gut Microbiome and COVID 19 Role of Probiotics on Gut Lung Axis

Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) has caused the greatest worldwide pandemic called Coronavirus-2019 (COVID-19) disease. The SARS-CoV-2 virus primarily attacks the respiratory tract, but it also disturbs the gastrointestinal system (GIT). The presence of the angiotensin-converting enzyme-2 (ACE-2) receptor in the intestinal epithelial cells, suggest the transmission of SARS-CoV-2 viruses from lungs to gut through systemic circulation. The virus detected in fecal samples of COVID-19 patients causes several gastrointestinal maladies including vomiting, diarrhea, and pain in abdomen. The gastrointestinal symptoms are associated with alterations in gut microbial composition, an increase in inflammatory cytokines and delayed virus clearance. Several studies demonstrated a decreased abundance of beneficial microbial species and increased opportunistic pathogens in the fecal samples of COVID-19 patients. The gut and lungs, share a bi-directional relationship called the “gut-lung axis” which is modulated by imbalanced gut microbiota. Since the gut microbes are suggested to play a vital role in health and disease by maintaining homeostasis of the immune system, therefore targeting the intestinal dysbiosis with beneficial microbial species, seems plausible to eventually diminish the effects of pulmonary infections and diseases. In this review, we have summarized studies demonstrating the gut-lung axis in association with gut dysbiosis in COVID-19 patients. In addition, the review also highlights the studies showing the potential role of probiotic supplementation in the amelioration of various respiratory infections and diseases. Data demonstrate that the restoration of gut microbial communities by probiotic supplementation can enhance lung capacity to combat respiratory viral infections including SARS-CoV-2.