Gut Microbiota Modulation as a Potential Target for the Treatment of Lung Infections

Abstract

The gastrointestinal and respiratory systems are colonized by a complex ecosystem of microorganisms called the microbiota. These microorganisms co-evolved over millions of years with the host, creating a symbiotic relationship that is fundamental for promoting host homeostasis by producing bioactive metabolites and antimicrobial molecules, and regulating the immune and inflammatory responses. Imbalance in the abundance, diversity, and function of the gut microbiota (known as dysbiosis) have been shown to increase host susceptibility to infections in the lungs, suggesting crosstalk between these organs. This crosstalk is now referred to as the gut-lung axis. Hence, the use of probiotics, prebiotics, and synbiotics for modulation of gut microbiota has been studied based on their effectiveness in reducing the duration and severity of respiratory tract infections, mainly owing to their effects on preventing pathogen colonization and modulating the immune system. This review discusses the role and responses of probiotics, prebiotics, and synbiotics in the gut-lung axis in the face of lung infections.

Ingestion, Immunity, and Infection: Nutrition and Viral Respiratory Tract Infections

“…The gut and airway microbiota are linked to respiratory tract health and immunity (‘gut-lung axis’) and modulation by pharmacological agents and pro- and synbiotics has in some studies been shown to manage RTIs ( 242 ). One implication of the dynamic bidirectional relationship between gut microbes and the immune system is that changes in the composition and metabolic activity of the gut microbiota can alter immune function, potentially altering host susceptibility to infection including within the pulmonary system.…”

“…A profound imbalance in gut microbiota can drive the progression of COVID-19 symptoms towards the acute respiratory distress syndrome (ARDS), and this development might be reinforced by the use of antiviral medication ( 266 ). Respiratory infectious diseases might thus be affected by gut dysbiosis characterized by a decline in beneficial commensals and enrichment of opportunistic pathogens ( 242 , 267 ). Administration of a Lactobacillus plantarum 06CC2 in mice with influenza-like disease, decreased expression of pro-inflammatory cytokines and increased the mRNA level of IFN-β, IFN-γ, OAS1a, and ISG15 in the lungs underscoring the antiviral activities of this probiotic ( 268 ).…”

A Novel Immunobiotics Bacteroides dorei Ameliorates Influenza Virus Infection in Mice

“…The increasing evidence indicates that alterations of gut microbiota may affect pulmonary immunity relevant to viral infections (41). Emerging experimental data highlight a crucial crosstalk between the gut microbiota and the lungs, termed as the gut-lung axis (42,43). The immune responses in the gut-lung axis depend on balanced gut microbiota composition (44).…”

“…The metabolites generated by intestinal microbiota, such as desaminotyrosine (DAT) and short chain fatty acids, can interact with host to exert immunoregulatory effects (42,43). Steed et al reported that C. orbiscindens protected mice against influenza by metabolizing quercetin substrate to DAT.…”

Shared and Specific Lung Microbiota with Metabolic Profiles in Bronchoalveolar Lavage Fluid Between Infectious and Inflammatory Respiratory Diseases

“…1,2 In particular, CAP is acquired outside of a health care setting, and characterized by alveolar infection and intense acute inflammatory responses. [3][4][5][6] CTD-ILD is a group of respiratory disorders characterized by dyspnea, and/or impaired pulmonary function, 7 and radiological and histopathological evaluation of the lungs shows patterns of chronic inflammation and fibrosis. 8 These pathophysiological disorders alter lung physiology and could be associated with lung microenvironment dysbiosis.…”