title: Heightened colon motor activity measured by a wireless capsule in patients with constipation: relation to colon transit and IBS.
abstract: Relationships of regional colonic motility to transit in health, constipation, and constipation-predominant irritable bowel syndrome (C-IBS) are poorly characterized. This study aimed to 1) characterize regional differences in colon pressure, 2) relate motor differences in constipation to colon transit, and 3) quantify the role of IBS in altered contractility with constipation. Colon pH and pressure were measured by wireless capsules in 53 healthy and 36 constipated subjects. Numbers of contractions >25 mmHg and areas under curves (AUC) were calculated for colon transit quartiles by time. Constipation was classified as normal transit (<59 h), moderate slow transit (STC) (59-100 h), and severe STC (>100 h). Twelve out of 36 constipated subjects had C-IBS; 24 had functional constipation. Numbers of contractions and AUCs increased from the first to the fourth quartile in health (P < 0.0001). Mean numbers of contractions in constipated subjects were similar to controls. Mean AUCs with normal transit (P = 0.01) and moderate STC (P = 0.004) but not severe STC (P = NS) were higher than healthy subjects. IBS was associated with greater mean numbers of contractions (P = 0.05) and AUCs (P = 0.0006) vs. controls independent of transit. Numbers of contractions increased from the first to fourth quartiles in moderate STC, C-IBS, and functional constipation; AUCs increased from the first to fourth quartiles in all groups (all P < 0.05). In conclusion, colon pressure activity is greater distally than proximally in health. Constipated patients with normal or moderately delayed transit show increased motor activity that is partly explained by IBS. These findings emphasize differential effects on transit and motility in different constipation subtypes.
authors.affiliation: University of Michigan Health System, Ann Arbor, Michigan, USA. whasler@umich.edu
authors.forename: William L
authors.initials: WL
authors.lastname: Hasler
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Saad
authors.forename: Satish S
authors.initials: SS
authors.lastname: Rao
authors.forename: Gregory E
authors.initials: GE
authors.lastname: Wilding
authors.forename: Henry P
authors.initials: HP
authors.lastname: Parkman
authors.forename: Kenneth L
authors.initials: KL
authors.lastname: Koch
authors.forename: Richard W
authors.initials: RW
authors.lastname: McCallum
authors.forename: Braden
authors.initials: B
authors.lastname: Kuo
authors.forename: Irene
authors.initials: I
authors.lastname: Sarosiek
authors.forename: Michael D
authors.initials: MD
authors.lastname: Sitrin
authors.forename: John R
authors.initials: JR
authors.lastname: Semler
authors.forename: William D
authors.initials: WD
authors.lastname: Chey
mesh_terms: D019540:Area Under Curve; D053704:Capsule Endoscopy; D016022:Case-Control Studies; D003106:Colon / Q000503:physiopathology*; D003113:Colonoscopy; D003248:Constipation / Q000175:diagnosis / Q000209:etiology / Q000503:physiopathology*; D005260:Female; D005772:Gastrointestinal Transit; D006801:Humans; D006863:Hydrogen-Ion Concentration; D043183:Irritable Bowel Syndrome / Q000150:complications / Q000175:diagnosis / Q000503:physiopathology*; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D009119:Muscle Contraction; D009130:Muscle, Smooth / Q000503:physiopathology*; D011312:Pressure; D012720:Severity of Illness Index; D011795:Surveys and Questionnaires