Serum squalene in postmenopausal women without and with coronary artery disease

Squalene, found in earlier studies in human atherosclerotic plaques, was measured in the serum of postmenopausal women with coronary artery disease (CAD) (n=25) and randomly chosen age-matched healthy controls (n=30). The squalene concentrations of the whole population ranged from 37.5 to 115.5 μg/dl, and were higher in serum of the CAD than healthy women (91.4±2.6 versus 65.2±2.6 μg/dl, P=0.000), a finding observed also in relation to cholesterol (43.8±1.8 versus 32.9±1.1 102×mmol/mol of cholesterol, P=0.000). The squalene concentration was also increased in chylomicrons, VLDL and d>1.006 g/ml lipoproteins, and the proportions to cholesterol in VLDL and d>1.006 g/ml lipoproteins. The respective squalene and cholesterol concentrations were related to each other in serum, VLDL and d>1.006 g/ml lipoproteins (r=0.52, 0.85 and 0.55, respectively), whereas the correlation with triglycerides was seen only in VLDL (r=0.84) over the whole population. Besides enhanced intestinal secretion, it remains to be shown whether higher serum squalene in postmenopausal coronary women is due to increased cholesterol synthesis or a defect in squalene conversion to lanosterol.