Abstract 1099: Reduced Fecal Sterol Excretion in Subjects with Low HDL Cholesterol Levels
Background. High-density lipoprotein (HDL) is generally considered to mediate the transport of cholesterol from the periphery to the liver. Fecal bile acid and neutral sterol excretion are the obligate end points of this reverse cholesterol transport (RCT) pathway. In recent murine studies no evidence was found for a correlation between HDL and fecal sterol excretion, which questioned the regulatory role of this lipoprotein in RCT. In this study, we evaluated the relationship between HDL and fecal sterol excretion in humans with low HDL cholesterol (HDL-c) versus controls.
Methods and Results. Fecal sterol excretion was studied in 6 men with familial hypoalphalipoproteinemia (FHA), 18 men with familial combined hyperlipidemia (FCH), and 7 healthy male controls. In the FHA, FCH and control groups, neutral sterol excretion was low (1.99 mg/kg/day IQR [0.58 –3.60]) medium (4.99 mg/kg/day IQR [1.88 –10.3]) and high (14.94 mg/kg/day IQR [8.2–22.0]), respectively. A similar pattern was identified for fecal bile acid excretion. In the combined group of all study subjects, a strong positive correlation between plasma HDL-c and fecal neutral sterol excretion was found (r=0.41; p=0.02). Interestingly, this correlation was not present in the controls.
Conclusions. This study indicates that at low plasma levels HDL-c correlates with fecal sterol excretion.