Cholesterol esterase activities in commercial pancreatic enzyme preparations and implications for use in pancreatic insufficient cystic fibrosis

Background: Although clinical symptoms in pancreatic insufficiency are often dramatically improved by pancreatic preparations, these often fail to normalize biochemical indicators of malabsorption. It seemed relevant, therefore, to investigate the amounts of cholesterol esterase in these preparations and, using in‐vitro methods, some of the activities of this enzyme. The enzyme is just as physiologically important as lipase in accomplishing lipid digestion and absorption. Methods: Cholesterol esterase was assayed in commercial pancreatic extract preparations, lyophilized pig pancreas and human duodenal fluid. The in‐vitro activities of the enzyme were also investigated on single and mixed dietary substrates. Results: Other than Creon, the commercial preparations showed negligible cholesterol esterase activities, whereas considerable activities were found in pancreatic tissue and duodenal fluids. In‐vitro, pig cholesterol esterase was confirmed to be dependent on 3‐hydroxy bile salt concentration for hydrolysis and synthesis and that the rate for hydrolysis greatly exceeds that of synthesis in normal concentrations of bile salts. However, with mixed lipid substrates, no bile salt concentration was found at which hydrolysis or synthesis predominates. Conclusions: When pancreatic or hepato‐biliary function is compromised, optimum lipid hydrolysis may not be achieved in therapeutic use, and the pig enzyme may perform differently to the human enzyme. In‐vivo trials may reveal whether augmentation of the commercial products with this enzyme would be worthwhile.