Appendix and Ulcerative Colitis: a Key to Explaining the Pathogenesis and Directing Novel Therapies?

Area of Science:

• Gastroenterology
• Immunology
• Microbiology

Background:

• The vermiform appendix, once deemed redundant, is increasingly implicated in inflammatory bowel diseases, particularly ulcerative colitis (UC).
• Mechanisms linking the appendix to UC pathogenesis and potential therapeutic roles remain largely unelucidated.

Approach:

• A comprehensive literature search was performed using PubMed and PubMed Central (inception to Nov 2021) with keywords including "Appendix," "UC," "Appendectomy," and "Peri-appendicular patch."
• Manual searching of reference lists from selected studies was conducted to identify additional relevant reports.

Key Points:

• Peri-appendicular inflammation is frequently observed in UC patients and may precede disease onset.
• Epidemiological studies suggest appendectomy might reduce UC risk or flares, though this is debated.
• Altered host-microbe interactions within the appendix are implicated in UC pathogenesis, potentially acting as a disease priming site.

Conclusions:

• Recent evidence points to a potential role for appendix microbes and immune cells in UC.
• The precise role of the appendix in ulcerative colitis pathogenesis requires further investigation.
• Understanding the appendix's involvement may reveal novel therapeutic strategies for UC.