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A putative anti-inflammatory role for TRPM8 in IBS 111 5 CGRP TRPM8 CD11c A B TRPM8 CD103 C D CGRP TRPM8 CM LM * * * * * * TRPM8 CD11c C IBS 0 2 4 6 8 10 TRPM8 +ve cells/field of view * E were increased in the IBS-D and IBS-M groups compared to IBS-C and IBS-undefined ( Supplementary Figure S5.2 ). Figure 5.1 TRPM8 expressed on human immune cell populations is increased in IBS patients and TRPM8 agonism reduces inflammatory cytokine release. A: In human colon (uninflamed), TRPM8 is expressed on CGRP immunoreactive fibers within the myenteric plexus. B: In inflamed colonic mucosa (Crohn’s disease), TRPM8 (purple) is expressed on CD11c (red) positive cells that are in close apposition to CGRP immunoreactive nerve endings. C & D: In IBS patient biopsies, high levels of TRPM8 are observed in the mucosa which co-label with CD11c+ and CD103+ abundantly. E: IBS patients (IBS) had significantly higher levels of TRPM8-immunoreactive cells compared to controls (C) ( N =28 IBS, N =7 C, * P =0.045). Data shown as median and IQR, with P <0.05 deemed significant. Circular (CM) and longitudinal muscular (LM) layers. Scale bar=10 μm. These results should be interpreted with caution due to the relatively small number of patients in each IBS-subtype. Interestingly, in IBS patients, mRNA expression of TRPM8 in the right-sided proximal colon was comparatively higher to that of the sigmoid colon ( N =24, P <0.001) ( Figure 5.2B ). In addition, sigmoid TRPM8 mRNA expression showed a significant positive association with abdominal pain scores as determined using a 2- week diary ( E =48.2, 95% CI 11.5;85.0, P =0.015, Figure 5.2C ).