Modulation of Gut Microbiota as a Potential Therapeutic Strategy in Asthma: A Scoping Review

Abstract

Asthma is a chronic inflammatory airway disease with a multifactorial origin, resulting from interactions between genetic and environmental factors. The diversity of the respiratory epithelial microbiota contributes to asthma development through epigenetic mechanisms, regulation of pro-inflammatory cytokines, modulation of T-cell tolerance, and overall immune responses. This process is influenced by interactions between the gut and lung microbiomes via the gut–lung axis. Aim: This review aims to map and evaluate the pharmacological activities, effectiveness, and safety of probiotics based on evidence from preclinical and clinical studies. This study was conducted as a scoping review to map existing evidence on the pharmacological activity, effectiveness, and safety of probiotics in asthma. The administration of probiotics in asthma patients shows therapeutic potential as an adjuvant therapy through the production of secondary metabolites in the gut, such as short-chain fatty acids (SCFAs) and indoles. Bacterial strains from the genera Bifidobacterium and Lactobacillus have demonstrated beneficial effects in clinical trials; however, the outcomes remain inconsistent. These variations may be attributed to differences in probiotic strains, colony-forming unit (CFU) counts, sample sizes, and the allergic phenotypes of the subjects. Evidence from preclinical and clinical studies indicates that probiotic therapy in asthma yields variable clinical outcomes but remains a promising therapeutic candidate that warrants further well-controlled, dose-ranging, and strain-specific studies. 

Keywords: asthma, probiotic, gut-lung axis.