P5381Post-prandial remnant lipoprotein metabolism in sitosterolemia

Background: It has been shown that sitosterolemic patients are vulnerable to diet-induced hypercholesterolemia. However, few data exist regarding post-prandial accumulation of lipoproteins in this rare condition. Methods: OFTT cream 50 g was given per body surface area (m2), blood sampling was performed at 2 hour intervals up to 6 hour. Plasma lipoprotein fractions and RLP fractions were determined in four sitosterolemic subjects with double mutations in ATP-binding cassette (ABC) sub-family G member 5 or member 8 (ABCG5 or ABCG8) gene (mean age=18yr, median LDL-C=154mg/dl), six heterozygous carriers (31yr, median LDL-C=105mg/dl), and five subjects with heterozygous FH (mean age=32yr, median LDL-C=221mg/dl). The area under curve (AUC) of lipids, including LDL-C, apolipoprotein B48 (ApoB48), RLP-TG, and RLP-C were evaluated. Results: After oral fat load, the AUC of LDL-C was significantly smaller in sitosterolemia subjects than that in heterozygous FH (977 mg/dl×hour vs. 1,333 mg/dl×hour, p<0.05), whereas, the AUC of ApoB48 was significantly larger in the sitosterolemic subjects compared with that of heterozygous FH (37 mg/dl×hour vs. 9 mg/dl×hour. P<0.05). Under these conditions, the AUCs of RLP-C, and RLP-TG levels were significantly larger in the sitosterolemic subject compared with those of heterozygous FH (92 mg/dl×hour vs. 53 mg/dl×hour, p<0.05, 375 mg/dl×hour vs. 238 mg/dl×hour, p<0.05, respectively), whereas, those of heterozygous carriers were comparable to those with heterozygous FH.