Ileal Paneth Cell Phenotype is a Cellular Biomarker for Pouch Complications in Ulcerative Colitis

Area of Science:

• Gastroenterology
• Immunology
• Genetics

Background:

• Complex immune diseases like inflammatory bowel disease (IBD), including Crohn's disease (CD) and ulcerative colitis (UC), require biomarkers integrating genetic and environmental factors for outcome prediction.
• Ileal Paneth cell phenotype (PCP), a measure of Paneth cell function, was previously identified as a cellular biomarker for CD.
• Given shared features between CD and UC, this study investigated PCP's association with molecular/genetic factors and outcomes in UC.

Purpose of the Study:

• To investigate if ileal Paneth cell phenotype (PCP) is associated with molecular/genetic features and clinical outcomes in ulcerative colitis (UC).
• To determine if PCP predicts outcomes in UC patients undergoing total colectomy and ileal pouch-anal anastomosis (IPAA), leveraging the high density of Paneth cells in the ileum.

Main Methods:

• Analysis of uninflamed ileal resection margins from UC patients with colectomy and IPAA for PCP and transcriptomic profiling.
• PCP assessment via defensin 5 immunofluorescence and genotyping using Immunochip.
• Integration of UC data with existing CD data to identify common IBD-related pathways and genes regulating PCP.

Main Results:

• The prevalence of abnormal ileal PCP in UC was 27%, similar to CD.
• Abnormal PCP in combined UC and CD cohorts correlated with secretory granule maturation pathways and innate immunity gene polymorphisms.
• Abnormal ileal PCP at colectomy was linked to increased pouch complications, including de novo CD and earlier onset of pouchitis.

Conclusions:

• Ileal Paneth cell phenotype (PCP) demonstrates biological and clinical significance in ulcerative colitis (UC).
• PCP serves as a valuable biomarker for predicting outcomes and complications in inflammatory bowel disease (IBD).