The inflammation-aging axis: Shared and distinct mechanisms in physiological gut aging and IBD-associated accelerated gut aging.

Inflammatory bowel disease (IBD) and physiological gut aging present with overlapping clinical features, including impaired barrier functioning, decreased nutrient absorption, and intestinal frailty. Emerging evidence indicates that even young IBD patients can exhibit gut phenotypes akin to those seen with aging. However, the two processes differ substantially in their underlying mechanisms. Gut aging is characterized by low-grade, chronic inflammation and gradual cellular senescence, whereas IBD involves persistent immune activation, cyclical tissue damage, and accelerated degenerative changes. This review systematically contrasts physiological gut aging and IBD-associated accelerated gut aging across several dimensions: cellular senescence and programmed cell death, immune cell remodeling, alterations in gut microbiota, changes in mesenteric adipose tissue, and the evolving role of the appendix. By integrating current advances in basic and translational research, this article highlights both the shared and distinct pathways driving gut dysfunction in aging and IBD, and underscores the importance of early recognition and targeted intervention for premature gut aging in clinical practice.