title: Visceral sensitivity and symptoms in patients with constipation- or diarrhea-predominant irritable bowel syndrome (IBS): effect of a low-fat intraduodenal infusion.
abstract: BACKGROUND
  Visceral hypersensitivity is common in Irritable Bowel Syndrome (IBS) patients, and symptoms exacerbate postprandially. Yet the effects of nutrients on visceral sensitivity and symptoms in these patients have not been fully explored.
  
  
  OBJECTIVE
  To evaluate the differences of visceral sensitivity and symptoms in healthy subjects and IBS patients during fasting and intraduodenal lipids infusion.
  
  
  METHODS
  Graded rectal distensions at fixed tension levels were performed in 16 IBS patients (8 IBS-C and 8 IBS-D) and 6 healthy subjects before and during intraduodenal lipids infusion at 0.5 kcal/min. Tension levels were increased in 4 gr increments up to 64 gr or discomfort during both conditions. At each step, perception and symptoms were measured by means of a validated questionnaire.
  
  
  RESULTS
  In basal conditions, perception thresholds in IBS patients and health were, respectively, 8 +/- 2 gr versus 32 +/- 9 gr (p < 0.001) with no changes during lipids. Intraduodenal lipids infusion significantly lowered threshold of discomfort in IBS patients in comparison to fasting (24 +/- 6 gr vs 34 +/- 4 gr; p < 0.05), while health tolerated all distension without discomfort. No differences of compliance, perception, or discomfort were observed between the two subgroups of patients at each tension step. The predominant symptom elicited in patients with IBS-C was abdominal pain (54%), while patients with IBS-D exhibited urgency (63%, p < 0.005); this pattern was maintained during lipids.
  
  
  CONCLUSIONS
  Intraduodenal lipids increase visceral sensitivity in both IBS-C and IBS-D; symptoms specificity in response to rectal distension is maintained in the postprandial period. Lipids may be responsible for the postprandial symptoms exacerbation in IBS.
authors.affiliation: Department of Medicine and Ageing Sciences, Section of Internal Medicine and Gastroenterology, Gabriele D'Annunzio University and Foundation, 66100 Chieti, Italy.
authors.forename: Maria Pia
authors.initials: MP
authors.lastname: Caldarella
authors.forename: Angelo
authors.initials: A
authors.lastname: Milano
authors.forename: Francesco
authors.initials: F
authors.lastname: Laterza
authors.forename: Flora
authors.initials: F
authors.lastname: Sacco
authors.forename: Crysanthi
authors.initials: C
authors.lastname: Balatsinou
authors.forename: Domenico
authors.initials: D
authors.lastname: Lapenna
authors.forename: Sante Donato
authors.initials: SD
authors.lastname: Pierdomenico
authors.forename: Franco
authors.initials: F
authors.lastname: Cuccurullo
authors.forename: Matteo
authors.initials: M
authors.lastname: Neri
mesh_terms: D000328:Adult; D003248:Constipation / Q000503:physiopathology*; D003967:Diarrhea / Q000503:physiopathology*; D004386:Duodenum; D005217:Fat Emulsions, Intravenous / Q000008:administration & dosage*; D005260:Female; D006801:Humans; D043183:Irritable Bowel Syndrome / Q000503:physiopathology*; D008297:Male; D010465:Perception; D011312:Pressure; D012007:Rectum / Q000503:physiopathology*; D012684:Sensory Thresholds; D014781:Viscera / Q000503:physiopathology*
chemical_list: D005217:Fat Emulsions, Intravenous