Gut-lung axis in asthma and obesity: role of the gut microbiome

Asthma is a heterogeneous disease whose severity is exacerbated by obesity. Despite its clinical importance, targeted therapies for asthma in obese patients remain limited. Recent evidence highlights the gut microbiome as a crucial factor linking metabolic and immune pathways involved in both asthma and obesity. This review explores the complex interplay between the gut microbiome, immune responses, and the gut-lung axis, emphasizing how microbial composition, diversity, and metabolites, such as short-chain fatty acids (SCFAs), influence airway hyperresponsiveness (AHR) and airway inflammation. Obesity alters the gut microbiome, contributing to systemic inflammation and metabolic dysfunction. Furthermore, asthma phenotypes related to obesity are associated with specific gut microbial profiles, suggesting a causal relationship. Animal studies have demonstrated that manipulation of the gut microbiome through diet, antibiotics, or microbial transplantation can alter asthma outcomes, particularly in obesity models. Given these findings, targeting the gut microbiome might be a promising therapeutic strategy for asthma in obese individuals. Potential interventions include probiotics, prebiotics and antibiotics, all of which have shown varying degrees of effectiveness in modulating airway inflammation and reducing asthma severity. This review provides a comprehensive overview of current knowledge and proposes future directions for microbiome-targeted therapies in managing severe asthma associated with obesity.