Hydrogenated fat consumption affects acylation-stimulating protein levels and cholesterol esterification rates in moderately hypercholesterolemic women

To determine whether hydrogenated fat consumption alters triglyceride metab olism and cholesterol esterification rates, 14 women (65-71 years of age) w ere provided with each of four diets for 5-week periods according to a rand omized cross-over design. The experimental diets contained either soybean o il (SO), low trans squeeze (SQM), medium trans tub (TM), or high trans stic k (SM) margarines. Triglyceride uptake by adipose tissue was determined by measuring plasma acylation-stimulating protein (ASP), FFA, glucose, and ins ulin levels, while rates of transfer and esterification rate of newly synth esized cholesterol (ER) were derived by using plasma CETP levels and the de uterium incorporation methodology. Plasma ASP levels were lowest (P < 0.05) in subjects on the SM diet (33.4 +/- 12.7 nM) compared with the SO (48.7 /- 17.0 nM) and SQM (50.7 +/- 15.7 nM) diets. Conversely, FFA were highest (P < 0.05) on the SM diet (0.86 +/- 0.45 mM) relative to all the other diet s. No differences were observed in plasma glucose and insulin levels among diets. A trend toward higher CETP levels after consumption of the SM diet w as observed. However, the ER was lowest (P < 0.05) after the SM (0.111 +/- 0.062 g.day(-1)) diet and highest after consumption of the SQM (0.216 +/- 0 .123 g.day(-1)) diet. In addition, ASP levels were negatively correlated wi th FFA (r = -0.63, P < 0.05), LDL cholesterol (r = -0.56, P < 0.05), and TG (r = -0.41, P < 0.05), whereas FFA was positively correlated with apolipop rotein B-containing lipoproteins (r = 0.58 and 0.47, for VLDL and LDL chole sterol, P < 0.05), and negatively correlated with HDL cholesterol (r = -0.5 1, P < 0.05). The ER was found to positively correlate with HDL cholesterol and HDL2 subfraction (r = 0.53 and 0.45, respectively, P < 0.05). Taken to gether, these data demonstrate that the alterations in circulating lipid le vels, commonly observed with consumption of hydrogenated fat-rich diets, ca n be explained in part by changes in ASP activity as well as newly synthesi zed cholesterol ER.