Beyond allergic progression: From molecules to microbes as barrier modulators in the gut-lung axis functionality

Area of Science:

• Immunology
• Environmental Health
• Microbiology

Background:

• The epithelial barrier hypothesis links barrier dysfunction to allergy development via tolerance breakdown.
• Environmental factors like pollution and lifestyle changes can compromise epithelial barrier integrity.
• Epithelial cells secrete cytokines (IL-25, IL-33, TSLP) that activate immune cells, promoting allergic responses.

Purpose of the Study:

• To review environmental agents affecting epithelial barrier function and allergic responses.
• To discuss dietary factors influencing allergenicity.
• To explore the role of gut microbiota and metabolites in epithelial barrier integrity, focusing on the gut-lung axis.

Main Methods:

• Literature review of environmental agents impacting epithelial barrier function.
• Analysis of dietary factors and their influence on allergic responses.
• Discussion of gut microbiota composition and its metabolites on distant epithelial barriers.

Main Results:

• Environmental factors (proteases, additives, xenobiotics) can alter epithelial barrier function.
• Dietary elements can modulate allergic responses.
• Gut microbiota and short-chain fatty acids impact both gut and lung epithelial barrier integrity.

Conclusions:

• Epithelial barrier dysfunction is a key factor in allergy development.
• Environmental exposures, diet, and gut microbiota composition significantly influence barrier function and allergic sensitization.
• The gut-lung axis highlights the systemic impact of gut health on respiratory allergies.