Absorption and metabolism of cholesterol in familial hypercholesterolaemia

1. The present study investigated the role of intestinal cholesterol absorption in the regulation of cholesterol metabolism and serum lipoprotein levels in 22 patients with heterozygous familial hypercholesterolaemia on low to normal cholesterol intake. 2. The results showed that the higher the dietary cholesterol absorption, the lower was the overall synthesis of cholesterol. Efficient cholesterol absorption actually reduced the elimination of cholesterol as faecal neutral sterols but not consistently as bile acids. 3. In multifactorial analysis, body mass index and dietary plant sterols were negatively associated with cholesterol absorption, but were unrelated to cholesterol synthesis. 4. Fractional cholesterol absorption was related only to the serum very-low-density triacylglycerol level. It was not associated with the total or low-density lipoprotein cholesterol levels. On the other hand, cholesterol synthesis was significantly associated with the serum concentrations of very-low-density lipoprotein and intermediate-density lipoprotein cholesterol and triacylglycerols, and with those of low-density lipoprotein triacylglycerols. 5. In conclusion, dietary cholesterol absorption is an essential regulator of cholesterol homoeostasis in familial hypercholesterolaemia, even in patients on low cholesterol intake.