Polymorphonuclear neutrophil depletion in ileal tissues reduces the immunopathology induced by Clostridioides difficile toxins.

Abstract

Introduction: Clostridioides difficile, a leading cause of healthcare-associated infections, causes significant morbidity and mortality. Its pathogenesis centers on TcdA and TcdB toxins, which disrupt intestinal integrity, trigger inflammation, and promote extensive neutrophil infiltration.

Objective: The main objective of this study was to evaluate the role of PMNs in CDI using neutrophil depletion using a murine-ileal-ligated loop.

Methods: Mice were treated with C. difficile toxins TcdA, TcdB, and TcdBv, with PMN depletion achieved via intraperitoneal injections of Ly6G/Ly6C antibody. Histopathological analysis, cytokine quantification, and MPO activity assays were performed to assess the inflammatory and tissue damage responses.

Results: PMN depletion significantly reduced histopathological damage and proinflammatory responses. TcdA induced the highest inflammation and epithelial damage, while TcdB showed lower activity, except for MPO. TcdBv_NAP1's activity was comparable to that of TcdB_NAP1 but less than TcdA. The findings indicate that TcdA's enterotoxin effects are more damaging than TcdBs from different strains and confirm the critical role of PMNs in CDI pathogenesis.

Conclusion: Our results show that PMN depletion reduced inflammatory responses and tissue damage, highlighting potential therapeutic strategies targeting PMN regulation. Further research on PMN extracellular traps (NETs) and their role in CDI is necessary to develop comprehensive treatments. Future studies should focus on combined in vivo and in vitro approaches to fully understand the pathological mechanisms and identify effective biomarkers for CDI therapy.