Abnormal levels of neuropeptide Y and peptide YY in the colon in irritable bowel syndrome.
OBJECTIVE
To assess the levels of gut peptides involved in gastrointestinal motor, secretory and sensory function in colonic biopsies in irritable bowel syndrome (IBS) patients and healthy controls.


METHODS
We studied 34 patients with IBS and 15 subjects without gastrointestinal symptoms. The predominant bowel pattern in the IBS patients was constipation in 17 patients (IBS-C) and diarrhoea in 17 patients (IBS-D). With radioimmunoassay, the levels of vasoactive intestinal peptide (VIP), substance P, neuropeptide Y (NPY) and peptide YY (PYY) were analysed in biopsies from the descending colon and ascending colon obtained during colonoscopy.


RESULTS
The IBS patients had lower levels of PYY in the descending colon than the controls, but the levels in the ascending colon did not differ. The NPY levels were lower in IBS-D than in IBS-C, both in the ascending colon and in the descending colon. Low levels of VIP were more common in IBS patients, but mean levels did not differ between groups. No group differences were observed for substance P. The levels of VIP, substance P and NPY were higher in the ascending colon than in the descending colon, whereas the opposite pattern was seen for PYY.


CONCLUSIONS
IBS patients demonstrate lower levels of PYY in the descending colon than controls. Colonic NPY levels differ between IBS subgroups based on the predominant bowel pattern. These findings may reflect the pathophysiology of IBS and the symptom variation within the IBS population.
Simrén
Magnus
M
Section of Gastroenterology, Department of Internal Medicine, Sahlgrenska University Hosptial, Göteborg, Sweden. magnus.simren@medicine.gu.se
Stotzer
Per-Ove
PO
Sjövall
Henrik
H
Abrahamsson
Hasse
H
Björnsson
Einar S
ES
D000328:Adult; D000368:Aged; D001706:Biopsy / Q000379:methods; D016022:Case-Control Studies; D003106:Colon / Q000737:chemistry*; D003109:Colonic Diseases, Functional / Q000150:complications / Q000378:metabolism*; D003248:Constipation / Q000209:etiology / Q000378:metabolism; D003967:Diarrhea / Q000209:etiology / Q000378:metabolism; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009478:Neuropeptide Y / Q000032:analysis*; D019894:Peptide YY / Q000032:analysis*; D013373:Substance P / Q000032:analysis; D014660:Vasoactive Intestinal Peptide / Q000032:analysis
D009478:Neuropeptide Y; D019894:Peptide YY; D013373:Substance P; D014660:Vasoactive Intestinal Peptide