title: Normalization of substance P levels in rectal mucosa of patients with faecal incontinence treated successfully by sacral nerve stimulation.
abstract: BACKGROUND
  Sacral nerve stimulation (SNS) may improve faecal incontinence by modulating rectal sensation. This study measured changes in the peripheral expression of various neural epitopes in response to SNS.
  
  
  METHODS
  Rectal mucosal biopsies were taken from 12 patients before and after temporary SNS, and from ten responders at 90 days after permanent stimulation. Sections were immunostained for substance P, transient receptor potential vanilloid (TRPV) 1, vasoactive intestinal peptide (VIP) and calcitonin gene-related peptide (CGRP). Levels were compared with those in nine continent controls.
  
  
  RESULTS
  Baseline levels of percentage area immunoreactivities of substance P (median 0.51 (95 per cent confidence interval 0.31 to 0.73) versus 0.13 (0.07 to 0.27) per cent; P < 0.001) and TRPV1 (0.76 (0.41 to 1.11) versus 0.09 (0.04 to 0.14) per cent; P < 0.001), but not of VIP (1.26 (0.37 to 2.15) versus 1.28 (0.39 to 2.17); P = 0.943), were significantly greater than in controls. Successful SNS resulted in a significant decrease in substance P immunostaining after temporary (0.15 (0.06 to 0.51) per cent; P = 0.051) and permanent (0.17 (0 to 0.46) per cent; P = 0.051) stimulation. Immunoreactivity of TRPV1, VIP, CGRP and neural markers showed no qualitative change.
  
  
  CONCLUSIONS
  Patients with faecal incontinence demonstrate normalization of raised rectal mucosal substance P levels following successful SNS.
authors.affiliation: Gastrointestinal Physiology Unit, Centre for Academic Surgery, Barts and The London, Queen Mary's School of Medicine and Dentistry, London, UK. m.gooneratne@qmul.ac.uk
authors.forename: M L
authors.initials: ML
authors.lastname: Gooneratne
authors.forename: P
authors.initials: P
authors.lastname: Facer
authors.forename: C H
authors.initials: CH
authors.lastname: Knowles
authors.forename: C L
authors.initials: CL
authors.lastname: Chan
authors.forename: P J
authors.initials: PJ
authors.lastname: Lunniss
authors.forename: S M
authors.initials: SM
authors.lastname: Scott
authors.forename: P
authors.initials: P
authors.lastname: Anand
authors.forename: N S
authors.initials: NS
authors.lastname: Williams
mesh_terms: D000328:Adult; D000368:Aged; D015740:Calcitonin Gene-Related Peptide / Q000378:metabolism; D004599:Electric Stimulation Therapy / Q000379:methods*; D004567:Electrodes, Implanted; D005242:Fecal Incontinence / Q000378:metabolism / Q000503:physiopathology / Q000628:therapy*; D006801:Humans; D007150:Immunohistochemistry; D007413:Intestinal Mucosa / Q000737:chemistry*; D008160:Lumbosacral Plexus; D008875:Middle Aged; D012007:Rectum / Q000737:chemistry*; D012677:Sensation / Q000502:physiology; D013373:Substance P / Q000378:metabolism*; D050916:TRPV Cation Channels / Q000378:metabolism
chemical_list: D050916:TRPV Cation Channels; C494482:TRPV1 protein, human; D013373:Substance P; D015740:Calcitonin Gene-Related Peptide