RESUMO
BACKGROUND: Transient receptor potential vanilloid 1 (TRPV1) cation channels, expressed on nociceptors, are well established as key contributors to abdominal pain in inflammatory bowel disease (IBD). Previous attempts at blocking these channels have been riddled with side effects. Here, we propose a novel treatment strategy, utilizing the large pore of TRPV1 channels as a drug delivery system to selectively inhibit visceral nociceptors. METHODS: We induced colitis in rats using intrarectal dinitrobenzene sulfonic acid. Visceral hypersensitivity, spontaneous pain, and responsiveness of the hind paws to noxious heat stimuli were examined before and after the intrarectal application of membrane-impermeable sodium channel blocker (QX-314) alone or together with TRPV1 channel activators or blockers. RESULTS: Intrarectal co-application of QX-314 with TRPV1 channel activator capsaicin significantly inhibited colitis-induced gut hypersensitivity. Furthermore, in the model of colitis, but not in naïve rats, QX-314 alone was sufficient to reverse gut hypersensitivity. The blockade of TRPV1 channels prevented this effect of QX-314. Finally, applying QX-314 alone to the inflamed gut inhibited colitis-induced ongoing pain. CONCLUSIONS: Selective silencing of gut nociceptors by a membrane-impermeable sodium channel blocker entering via exogenously or endogenously activated TRPV1 channels diminishes IBD-induced gut hypersensitivity. The lack of effect on naïve rats suggests a selective analgesic effect in the inflamed gut. Our results suggest that in the colitis model, TRPV1 channels are tonically active. Furthermore, our results emphasize the role of TRPV1-expressing nociceptive fibers in colitis-induced pain. These findings provide proof of concept for using charged activity blockers for the blockade of IBD-associated abdominal pain.
Here, we show that the selective silencing of a specific subtype of nociceptive neurons innervating the gut mitigates colitis-induced visceral hypersensitivity and pain. Our results provide a basis for developing effective and selective treatments for inflammatory bowel disease pain.
RESUMO
BACKGROUND: Faecal incontinence is a common debilitating condition associated with poor quality of life that generates substantial economic strain on healthcare systems. OBJECTIVES: We aimed to evaluate, in a tertiary referral population presenting with faecal incontinence, the impact of suffering additional disorders of gut-brain interaction (DGBI) on symptom severity, anxiety, depression and quality of life. METHODS: Design: Retrospective cohort study. SETTING: Tertiary referral Neurogastroenterology centre. PATIENTS: All patients presenting with faecal incontinence from 2007 to 2020 were included. MAIN OUTCOME MEASURES: The results from structured medical and surgical questionnaires including Rome III Integrative Questionnaire, Faecal Incontinence Severity Index, Hospital Anxiety and Depression Scale, SF-36, and anorectal physiology were analysed using Stata version 17. Patients were categorised into 3 groups: 0-1 additional DGBI, 2 DGBIs, and 3+ DGBI. Statistical significance was defined as p < 0.05 (two-tailed). KEY RESULTS: Faecal incontinence patients (n = 249; mean age 63.4 ± 12.6 years; 93.6% female, 48.1% urge subtype) met diagnostic criteria for mean 2.2 additional DGBI each, mostly affecting bowel (n = 231, 42.4%) and anorectal (n = 150, 27.5%) regions. A greater number of DGBIs was associated with higher faecal incontinence symptom severity (p < 0.001), higher anxiety (p = 0.002) and depression (p = 0.003), and worse quality of life in areas of mental health (p = 0.037) and social effect (p < 0.001). Patients with a greater number of concurrent DGBI demonstrated a greater family history of gastrointestinal problems (p = 0.004). There were no associations found between a greater amount of DGBIs and anorectal physiology. CONCLUSIONS AND INFERENCES: A greater number of additional DGBIs in faecal incontinence patients was associated with worse faecal incontinence symptoms, higher anxiety and depression scores, and worse quality of life but was unrelated to physiology. This highlights the need to proactively search for comorbid DGBI in patients presenting with faecal incontinence.