Cholesterol malabsorption in pancreatic insufficiency: Effects of enzyme substitution

Abstract

Defective lipolysis, steatorrhea, and hypocholesterolemia characterize pancreatic insufficiency. Lipid metabolism in pancreatic insufficiency was studied by measuring serum lipoproteins, cholesterol absorption with double labels and serum plant sterols, and bile acid and cholesterol synthesis with fecal and dietary steroid analysis and cholesterol precursor sterols before and during exogenous pancreatic enzyme substitution. Baseline fecal fat, masses, bile acids and neutral steroids, and cholesterol synthesis were increased, whereas cholesterol absorption was markedly reduced. In fact, the present data suggest that sterol absorption may be disturbed more sensitively than fat absorption in pancreatic insufficiency. Enzyme substitution significantly reduced fecal fat, masses, bile acids and neutral steroids, and synthesis of cholesterol and improved cholesterol absorption in relation to serum cholesterol, although normal values were not obtained. Serum level of high-density lipoprotein cholesterol was significantly elevated by exogenous enzymes, whereas levels of cholesterol or triglycerides in other lipoproteins remained unchanged. Improved sterol absorption increased also serum levels of plant sterols and reduced levels of cholesterol precursors and cholesterol synthesis and precursor sterol-plant sterol ratios. Thus, reduced intestinal lipolysis with expanded oil phase appears to be a major reason for impaired cholesterol absorption, causing enhanced cholesterol and, consequently, bile acid synthesis and reduced serum cholesterol level. Exogenous enzyme substitution seems partly to correct these abnormalities, improvements of which can be monitored by the gas-liquid chromatographic determination of serum plant sterols or cholesterol precursor-plant sterol ratios.