Gut Antimicrobial Peptides α-Defensins Are Depleted in Liver Cirrhosis, Linked to Bacterial Toxin Leakage

Prospective study of 40 patients with decompensated cirrhosis, 27 with compensated cirrhosis, and 27 healthy controls. All underwent duodenal biopsy. HD5 and HD6 expression in intestinal crypts was evaluated by immunohistochemistry and immunofluorescence. Serum endotoxin was quantified. Intraepithelial T-lymphocytes and lamina propria B-lymphocytes were counted.

Bacterial translocation (bacteria leaking from the gut into the bloodstream) is a major cause of infection and death in cirrhosis patients. Understanding that antimicrobial peptide depletion underlies this gut barrier failure opens new therapeutic avenues — potentially boosting defensin expression could prevent infections without relying solely on antibiotics, which risk resistance.

This study connects antimicrobial peptide biology with liver disease, showing that the gut's first line of defense — Paneth cell defensins — fails in cirrhosis. This adds to understanding of the gut-liver axis, where gut barrier integrity directly impacts liver disease outcomes. The finding could have implications beyond cirrhosis for any condition where gut barrier function is compromised.

The study is cross-sectional, so it cannot determine whether defensin loss causes gut barrier dysfunction or results from it. The biopsy location (duodenum) may not represent the entire intestinal barrier. The mechanism by which cirrhosis reduces defensin expression was not investigated. Sample sizes, while reasonable, are modest for subgroup analyses.