Increased capsaicin receptor TRPV1-expressing sensory fibres in irritable bowel syndrome and their correlation with abdominal pain.
Level 4 - case-series / case-control
Case-control study comparing mucosal biopsy markers between IBS patients and controls
PubMed 18252749 · doi:10.1136/gut.2007.138982
What was done
Researchers collected rectosigmoid biopsies from 23 IBS patients (Rome II criteria) and 22 control subjects. Abdominal pain scores were measured via a validated questionnaire. Using immunohistochemistry, investigators quantified TRPV1-, substance P-, and PGP9.5-expressing nerve fibres, mast cells (c-kit), and lymphocytes (CD3 and CD4), and assessed their relationship with abdominal pain scores via multivariate regression.
What was found
Median TRPV1-immunoreactive fibres were increased 3.5-fold in IBS patients compared with controls (p < 0.0001). IBS patients also showed significant increases in substance P fibres (p = 0.01), total PGP9.5 nerve fibres (p = 0.002), c-kit mast cells (p = 0.02), and CD3 lymphocytes (p = 0.03). In multivariate regression analysis, only TRPV1-immunoreactive fibres (p = 0.005) and mast cells (p = 0.008) were significantly related to abdominal pain scores.
Why it matters
This study links sensory nerve receptor changes and mast cell infiltration directly to abdominal pain in IBS, identifying TRPV1 as a potential target for treating visceral hypersensitivity.
Limits
The sample size is small (n = 45 total). The cross-sectional case-control design shows correlation rather than causation, and the abstract lacks absolute cell/fibre counts, confidence intervals, and IBS subtype stratification.
Cited by
- supports In irritable bowel syndrome (IBS), enteric nervous system nerves fire at a lower threshold and there is an increased concentration of pain-signaling TRPV1 receptors in the colon.