Intestinal pH and Gastrointestinal Transit Profiles in Cystic Fibrosis Patients Measured by Wireless Motility Capsule
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Background and Aims
The effect of the cystic fibrosis transmembrane conductance regulator protein (CFTR) defect in pancreatic insufficient (PI) patients with cystic fibrosis (CF) on the gastrointestinal pH profile is poorly defined. Adequate and efficient neutralization of the gastric acidity in the duodenum is important for nutrient absorption and timely release of pancreatic enzyme replacement therapy (PERT). We utilized a wireless motility capsule (WMC) to study intestinal pH profile and gastrointestinal transit profile in CF subjects.
WMC studies were done on ten adult CF patients with PI while off acid suppression medication and ten age, gender and BMI matched healthy controls. Mean pH over 1 min increments and area under the pH curve over 5 min increments was calculated for the first hour post gastric emptying. Paired t-test was used to compare means of the pH recordings, transit profiles and analysis of time interval required to reach and maintain pH >5.5 and 6.0.
A statistically significant difference was observed between mean pH values during the first 23 min of small bowel transit (p < 0.05). In CF subjects, there was a significant delay in time interval required to reach and sustain pH 5.5 and pH 6.0 (p < 0.001), which is required for PERT dissolution. Only small bowel transit in CF subjects was noted to be significantly delayed (p = 0.004) without a compensatory increase in whole gut transit time.
We have demonstrated a significant delay in the small intestinal transit and a deficient buffering capacity required to neutralize gastric acid in the proximal small bowel of patients with CF.
KeywordsCystic fibrosis pH profile CFTR PERT Small bowel transit Wireless motility capsule
Cystic fibrosis transmembrane conductance regulator protein
Pancreatic enzyme replacement therapy
Wireless motility capsule
Area under the curve
Gastric emptying time
Small bowel transit time
Colon transit time
Whole gut transit time
Body mass index
The authors would like to thank Gregory E. Wilding for an early discussion on analytical methods of SmartPill data. This study was funded by a grant from Cystic Fibrosis Foundation Therapeutics, Inc. Funding #: BOROWI08A0.
Conflict of interest
Jack Semler is an employee of SmartPill Corporation and owns stock in the corporation. Daniel Gelfond, Changxing Ma and Drucy Borowitz have no conflict of interest.
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