External Factors Affecting Gastrointestinal Barrier and Mucosal Immunity at High Altitude

Abstract

High altitude regions above 2,700 meters pose unique physiological challenges to travellers, including hypoxia caused by decreased oxygen levels. Gastrointestinal issues such as nausea, vomiting, and anorexia are common in high altitude sojourners. The gastrointestinal barrier is composed of epithelial cells connected with tight junctions, desmosomes, and covered with a thick layer of mucous. The mucosal and immunological barriers work together to regulate intestinal homeostasis and prevent harmful pathogens from entering the system. Any damage to the gastrointestinal barrier can lead to an increase in permeability which can cause harmful microbial toxins and unwanted substances to enter the bloodstream, triggering an inflammatory response. External factors such as hypoxia and intense physical workouts at high altitude can disrupt the barrier and lead to inflammation and microbial dysbiosis, which changes the normal population of gut microbiota and can cause gastrointestinal discomfort. This review aims to examine the effects of these external factors on the gastrointestinal barrier and highlights the importance of therapeutic and dietary interventions to manage high altitude induced mucosal barrier dysfunction and restore immunological homeostasis of the gut.