title: Alterations in mucosal neuropeptides in patients with irritable bowel syndrome and ulcerative colitis in remission: a role in pain symptom generation?
abstract: BACKGROUND
  Irritable bowel syndrome (IBS) is a functional gastrointestinal disorder characterized by chronic abdominal pain. The transient receptor potential vanilloid 1 (TRPV1) channel, which is involved in visceral pain signalling, has been shown to be up-regulated in IBS. Activation of TRPV1 leads to the release of neuropeptides, such as somatostatin and substance P (SP). We hypothesized that increased pain perception in IBS could be explained by increased transcription in TRPV1 and/or altered levels of neuropeptides. We therefore assessed the transcription of TRPV1 and the mucosal concentration of somatostatin and SP in IBS in comparison to healthy volunteers and patients with ulcerative colitis (UC) in remission as disease controls, and to ascertain their relationship to pain symptoms.
  
  
  METHODS
  Sigmoid colonic mucosal samples were collected from 12 patients with IBS, 34 patients with UC in remission and 9 healthy volunteers, in which groups TRPV1 mRNA levels were determined using quantitative polymerase chain reaction and neuropeptide concentrations by radioimmunoassay. Pain symptom intensity was determined by questionnaires.
  
  
  RESULTS
  Transcription of TRPV1 as well as the concentration of neuropeptides were significantly higher in IBS, but only the former correlated with pain symptom severity.
  
  
  CONCLUSIONS
  Increased transcription of TRPV1 may provide a possible explanation for pain generation in IBS. While the neuropeptides SP and somatostatin were both found to be increased in IBS, these changes are not sufficient to explain pain generation. Pain generation in IBS is probably explained by a complex redundancy in the regulation of local nociceptive mechanisms, which remains a subject of intensive investigation.
authors.affiliation: Top Institute Food and Nutrition, Wageningen, The Netherlands. daniel.keszthelyi@maastrichtuniversity.nl
authors.forename: D
authors.initials: D
authors.lastname: Keszthelyi
authors.forename: F J
authors.initials: FJ
authors.lastname: Troost
authors.forename: D M
authors.initials: DM
authors.lastname: Jonkers
authors.forename: Z
authors.initials: Z
authors.lastname: Helyes
authors.forename: H M
authors.initials: HM
authors.lastname: Hamer
authors.forename: S
authors.initials: S
authors.lastname: Ludidi
authors.forename: S
authors.initials: S
authors.lastname: Vanhoutvin
authors.forename: K
authors.initials: K
authors.lastname: Venema
authors.forename: J
authors.initials: J
authors.lastname: Dekker
authors.forename: J
authors.initials: J
authors.lastname: Szolcsányi
authors.forename: A A
authors.initials: AA
authors.lastname: Masclee
mesh_terms: D015746:Abdominal Pain / Q000209:etiology* / Q000378:metabolism / Q000503:physiopathology; D003093:Colitis, Ulcerative / Q000150:complications / Q000378:metabolism* / Q000503:physiopathology; D012809:Colon, Sigmoid / Q000378:metabolism* / Q000503:physiopathology; D005260:Female; D006801:Humans; D007413:Intestinal Mucosa / Q000378:metabolism* / Q000503:physiopathology; D043183:Irritable Bowel Syndrome / Q000150:complications / Q000378:metabolism* / Q000503:physiopathology; D008297:Male; D013004:Somatostatin / Q000378:metabolism*; D013373:Substance P / Q000378:metabolism*; D050916:TRPV Cation Channels / Q000235:genetics / Q000378:metabolism
chemical_list: D050916:TRPV Cation Channels; C494482:TRPV1 protein, human; D013373:Substance P; D013004:Somatostatin