Liver disease does not affect lipolysis as measured with the C-13-mixed triacylglycerol breath test in children with cystic fibrosis

Background: Liver disease associated with cystic fibrosis may not only limi t the solubilisation and absorption of the products of fat digestion, but a lso may depress the activity of pancreatic Lipase. The purpose of this stud y was to measure the effect of Liver disease on triacylglycerol Lipolysis u sing the C-13-mixed triacylglycerol breath test. Methods: Forty children with cystic fibrosis took C-13-mixed triacylglycero l with a standard breakfast and the child's normal pancreatic enzyme replac ement therapy. Breath samples were collected before and every 30 minutes af ter ingestion for 6 hours. The cumulative percentage dose of C-13 recovered at 6 hours was calculated from sequential measurements of C-13 enrichment of breath CO2, measured by isotope ratio mass spectrometry. Liver abnormali ties and portal hypertension were defined by ultrasound scan and clinical e xamination. Results: Twenty-four children had liver abnormalities, including 5 with por tal hypertension. No difference was found between cumulative percentage dos e of C-13 recovered at 6 hours in 16 children with no liver abnormality (me an, 21.4% +/- 11.1%), 19 children with liver abnormalities (22.2% +/- 10.0% ) and 5 children with portal hypertension (20.9% +/- 7.1%). Conclusion: Intestinal lipolysis is not reduced in cystic fibrosis Liver di sease when measured using the C-13 mixed triacylglycerol breath test. These findings affirm the test's use as an indirect measure of fat digestion tha t is not affected by inadequate intraluminal bile salts or liver disease.