Visceral sensitivity and symptoms in patients with constipation- or diarrhea-predominant irritable bowel syndrome (IBS): effect of a low-fat intraduodenal infusion.
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.
Caldarella
Maria Pia
MP
Department of Medicine and Ageing Sciences, Section of Internal Medicine and Gastroenterology, Gabriele D'Annunzio University and Foundation, 66100 Chieti, Italy.
Milano
Angelo
A
Laterza
Francesco
F
Sacco
Flora
F
Balatsinou
Crysanthi
C
Lapenna
Domenico
D
Pierdomenico
Sante Donato
SD
Cuccurullo
Franco
F
Neri
Matteo
M
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*
D005217:Fat Emulsions, Intravenous