Nitric Oxide in the Intestinal Stem Cell Niche: A Spatial Model of Nitrosative Stress and Clonal Evolution in...

Chronic colitis is a major risk factor for colitis-associated colorectal cancer (CAC), but the mechanisms linking recurrent inflammation to crypt-level dysplasia remain incompletely defined. This review examines whether spatially heterogeneous nitric oxide (NO) and reactive nitrogen species (RNS) exposure within the intestinal stem cell (ISC) niche may connect inflammation, DNA damage, stemness, and clonal evolution in CAC.

This narrative, mechanistic review synthesized peer-reviewed English-language studies identified through PubMed/MEDLINE, Web of Science, and Google Scholar through 1 May 2026. Included literature addressed NO/NOS biology, ISC and crypt niche regulation, colitis-associated carcinogenesis, nitrosative DNA damage, cancer stem-like traits, and epithelial, stromal, immune, vascular, lymphatic, microbial, neural, and glial NO sources.

Constitutive NOS-derived NO supports mucosal perfusion, barrier integrity, and homeostasis, whereas colitis-associated NOS upregulation can generate high-flux NO, peroxynitrite, epithelial injury, and mutagenic nitrosative stress. The reviewed evidence supports a spatial NO/RNS-field model in which recurrent crypt-level nitrosative microdomains influence DNA damage, repair stress, Wnt/stemness signaling, immune selection, microbiome-redox interactions, and cancer stem-like programs. However, direct causal evidence in human colitic ISCs remains limited.

Chronic colitis may create recurring NO/RNS-rich crypt microenvironments that favor survival and expansion of damaged or NO-tolerant stem/progenitor clones. This model may guide crypt-resolved biomarker development and locally restricted prevention strategies, but prospective validation is required.