Abnormal Biliary Lipid Composition in Cystic Fibrosis

Abstract

Because of the increased incidence of gallstones in cystic fibrosis we compared biliary lipid composition in 26 patients with cystic fibrosis, seven children with cholelithiasis but no cystic-fibrosis and 13 controls. Eighteen of the cystic fibrosis group had cholecystograms, and only one had gallstones. In 14 patients with cystic fibrosis who had stopped taking pancreatic enzymes for one week molar percentage of lipid composition accounted for by cholesterol (mean +/- S.E., 16.3 +/- 2.9) and saturation index (2.0 +/- 0.3) were comparable to values of the cholelithiasis group and higher (P less than 0.01) than those of controls. In 12 patients with cystic fibrosis taking pancreatic enzymes, molar percentage of cholesterol (8.6 +/- 1.7) and saturation index (1.0 +/- 0.1) did not differ from those of controls; in cystic fibrosis there was a preponderance of cholic over chenodeoxycholic acid both off (1.7 +/- 0.2) and on (1.9 +/- 0.3) therapy as compared to the cholelithiasis (0.7 +/- 0.1) and control (0.8 +/- 0.0) groups. The glycine/taurine ratio of conjugated bile acids were lower in enzyme-treated patients with cystic fibrosis (3.7 +/- 0.6) than in patients off treatment (6.4 +/- 1.0), but was higher (P less than 0.01) than in controls (1.8 +/- 0.2). Bile is lithogenic in untreated cystic fibrosis and responds to pancreatic enzymes.

Effect of Taurine Supplements on Fat Absorption in Cystic Fibrosis

“…The increased G/T ratio of bile acids found in CF (9) has been confirmed by others (10, 1 1) and attributed to malabsorption of bile acids. Although fasting (1 1) and postcholecystokynin (10) total duodenal bile acids may be above the critical micellar concentration, it is likely that a significant proportion may not be physiologically available for the micellar solubilization of lipolytic products.…”

“…A poor response of the lipolytic phase defect to available pancreatic enzyme supplements (44) and concomitant alterations of bile salt metabolism (9,45), compromising micellar solubilization of lipolytic products, are also important factors. Claims of added efficacy of a conventional pancreatic enzyme preparation with added bile salts have not been substantiated (46).…”

“…The percentage of bile acids conjugated with taurine is closely correlated with the hepatic pool of taurine which in turn is dependent on the dietary intake (4). The G/T ratio of conjugated bile acids increases in newborns on taurine-free formulas (5), in patients on TPN (6, 7), short bowel syndrome (8), and CF (9).…”

Diagnosis and Treatment of Intestinal Malabsorption in Cystic Fibrosis

“…9 In CF, taurine-conjugated bile acids are deficient in plasma and bile. 10 There is some evidence that oral taurine (30 mg/kg/day) will correct the deficiency and improve malabsorption. 107 …”

“…[6][7][8] There is increased fecal loss of bile salts 9 and a relative increase in glycine-conjugated and a decrease in taurine-conjugated bile salts. 10 Glycine-conjugated bile salts are less effective at lipid solubilization. Intestinal mucosal ion transport abnormalities affecting both water and electrolyte transport appear to be related to the basic CFTR defect.…”