Visceral fat positively correlates with cholesterol synthesis in dyslipidaemic patients.

BACKGROUND: Quantification of plasma noncholesterol sterols allows the study of cholesterol absorption and synthesis. A pattern of low cholesterol absorption and high synthesis has been demonstrated in patients with obesity and insulin resistance. To understand the relationship between cholesterol absorption/synthesis and visceral obesity, we investigated surrogate markers of cholesterol absorption (campesterol and sitosterol) and synthesis (lathosterol) in dyslipidaemic patients with different representation of abdominal fat, estimated by ultrasonographic measurement of visceral fat area (VFA).
METHODS: In 126 patients with primary hyperlipaemias, plasma sitosterol, campesterol and lathosterol were determined by gas chromatography coupled with mass spectrometry. Visceral and subcutaneous fats were evaluated by ultrasonography. The study population was divided into two groups on the basis of VFA median values, below/equal and above 154 cm(2) . RESULTS Patients with higher VFA had significantly higher lathosterol levels (median 109 vs. 76 × 10(2) μmol/mmol cholesterol P < 0·004), body mass index, waist circumference, blood pressure, triglycerides, insulin, homoeostatic model assessment (HOMA)-IR and lower high-density lipoprotein (HDL)-C. VFA was positively correlated with lathosterol (ρ = 0·35, P < 0·001) and negatively with HDL-C (ρ = -0·43, P < 0·001), campesterol (ρ = -0·23, P = 0.01) and sitosterol (ρ = -0·35, P < 0·001). VFA was an independent predictor of lathosterol values (β = 0·389, P < 0·0001, P of the model < 0·0001);age, systolic blood pressure, BMI, waist circumference, triglycerides, HDL-C and HOMA failed to enter the final equation.
CONCLUSIONS: In hyperlipidaemic patients, the amount of visceral fat correlates with cholesterol synthesis; the use of ultrasonographic detection of abdominal adiposity allows a better characterization of cholesterol pathway, potentially useful for a tailored therapeutic approach.