Tissue factor in ulcerative colitis, with and without concomitant primary sclerosing cholangitis.

Area of Science:

• Gastroenterology
• Immunology
• Oncology

Background:

• Ulcerative colitis (UC) with primary sclerosing cholangitis (PSC) presents a unique phenotype (PSC-UC) associated with increased colorectal cancer risk.
• Current PSC-UC diagnosis relies solely on clinical observation.
• Tissue factor (TF) shows promise in UC diagnostics and colorectal cancer prognostication.

Purpose of the Study:

• To investigate TF expression in an inflammatory bowel disease (IBD) cohort.
• To differentiate TF expression patterns between UC and PSC-UC patients.

Main Methods:

• Immunohistochemistry was used to analyze TF expression in colonic biopsies from UC, PSC, and healthy control groups.
• Flow cytometry was employed to confirm mononuclear cell contribution to TF expression.

Main Results:

• TF was localized in subepithelial pericryptal sheath cells, mononuclear cells, and intestinal stroma.
• Unlike UC, PSC-UC showed low TF activity despite inflammation.
• Stromal TF positivity was specifically observed during active inflammation.

Conclusions:

• The findings suggest a distinct pathogenesis in PSC-UC compared to classical UC, characterized by a different inflammatory environment.
• Stromal TF is identified as a potential new biomarker for colonic inflammation.