Wednesday October 1, 2003: Poster Session 228 Lipid and lipoprotein metabolism apo E in the plasma and is taken-up by LDL receptors. In the current study, LDE labeled with 3 H-cholesterol (C) and 14 C-cholesteryl oleate (CO) was injected into 15 coronary artery disease patients 24 h before myocardial revas- cularization surgery. Fragments of aortic, radial, internal thoracic arteries, safenous vein and pericardium discarded during surgery were collected and analyzed for radioactivity together with serial plasma samples. Aorta showed the greatest uptake of LDE C. The radioactive counting of LDE CO was greater than that of LDE C in all the plasma samples collected over 24 h, but the uptake of LDE C was markedly greater than that of CO in all vessel fragments (p< 0.05). The uptake of LDE C by aorta was eight-fold greater than that of LDE CO, four-fold greater in the internal thoracic artery, two-fold greater in the radial artery, eight-fold greater in safenous vein and two-fold greater in pericardium. In conclusion, the remarkably greater vessel tissue uptake of C compared with CO suggests that C dissociate from the microemul- sion particles and precipitat in the vessels. Considering LDE as an artificial microemulsion model for LDL, our results suggest that dissociation of C from lipoprotein particles and deposition in the arterial wall may constitute a novel atherogenic mechanism. 3P-0757 Increased circulating malondialdehyde-modified LDL in the patients with familial combined hyperlipidemia and its relation with the hepatic lipase activity K. Yamazaki 1 , H. Bujo 2 , M. Shibasaki 1 , K. Takahashi 1 , Y. Saito 1 . 1 Dept of Clinical Cell Biology; 2 Dept. of Genome Research & Clinical Application, Chiba University Graduate School of Medicine, Japan Recent establishment of sensitive detection system for malondialdehyde- modified (MDA)-LDL, which is one of oxidized lipoproteins, showed its increased circulating level in the patients with CAD. In order to know the atherogenic lipoproteins resulted from the dyslipidemia observed in Familial combined hyperlipidemia (FCHL), we measured the serum MDA-LDL level in the patients. The circulating MDA-LDL level and the ratio of MDA-LDL and LDL-C in FCHL were significantly higher than those in control, which are adjusted about the age, serum TC, LDL-C and HDL-C levels, respectively. The circulating MDA-LDL level and the ratio of MDA-LDL and LDL-C were negatively correlated (R=-0.635, P<0.01 and R=-0.702, P<0.01, respectively) with hepatic lipase activity in FCHL. The serum MDA-LDL level and the ratio of MDA-LDL and LDL-C were in the subjects with T/T genotypes in the hepatic lipase (HL) C-514T polymorphism were significantly increased compared to those with C/C genotype, respectively. The subjects with T/T genotype showed the activities to 65% and 79% of those in the subjects with C/C genotype in male and female, respectively. The intima-media thickness (IMT) of carotid artery was significantly higher (p<0.05) in the subjects with T/T genotype than those with C/C genotype in male. These findings indicate that the circulating MDA-LDL level is possibly contributing the atherogenic process in FCHL. 3P-0758 Single-nucleotide polymorphisms in the acyl-CoA:cholesterol acyltransferase-1 gene in patients with hyperlipidemia K. Katsuren 1 , S. Fukuyama 1 , K. Takata 2 , T. Ohta 1 . 1 Dept. of Pediatrics, Fac. of Medicine, University of the Ryukyus, Okinawa; 2 Dept. of Internal Medicine, Hiroshima Hospital of West-Japan Railway Company, Japan Objective: Acyl-CoA:cholesterol acyltransferase (ACAT) plays important roles in cellular cholesterol homeostasis. Two isoforms of ACAT have been reported (ACAT-1 and ACAT-2). ACAT inhibitors can not only prevent atherosclerosis formation, but may also induce its regression in animals. In humans, an ACAT inhibitor was shown to have a lipid-lowering effect. The present study was carried out to clarify the relationship between ACAT-1 gene variants and hyperlipidemia. Methods and Results: To identify genetic variants, we screened 30 sub- jects with hyperlipidemia by direct sequencing. As a result, a missense variant (R526G), and a variant in the 5’ untranslated region (-77G/A) were identified. The genotype frequencies of each variant were determined in 183 unrelated normolipidemic controls and 174 unrelated hyperlipidemic patients. The alleles frequencies of the R526G variant in normolipidemic controls and hyperlipidemic patients were 0.686 and 0.635, respectively. The alleles fre- quencies of the -77G/A variant in normolipidemic controls and hyperlipidemic patients were 0.505 and 0.506, respectively. Differences in allele frequencies between normolipidemic controls and hyperlipidemic patients were not signif- icant in both variants. R526G variant did not affect plasma concentrations of lipids or apolipoproteins in subjects studied. However, among hyperlipidemic patients, plasma concentrations of HDL-C and apoA-I in patients with -77G/A variant were significantly higher than those in patients without variant. Conclusion: Two variants in ACAT-1 gene were identified in patients with hyperlipidemia. -77G/A variant affects plasma HDL concentrations only in hyperlipidemic patients. These data suggest that the intracellular FC concentration might modulate plasma HDL concentrations. 3P-0759 LRP-1B, a LDL receptor family member, reduces the migration of smooth muscle cells in vitro K. Tanaga 1 , H. Bujo 2 , K. Takahashi 1 , W.J. Schneider 3 , Y. Saito 1 . 1 Dept of Clinical Cell Biology, 2 Dept. of Genome Research & Clinical Application, Chiba University Graduate School of Medicine, Japan; 3 Dept. of Molecular Genetics, Biocenter, University of Vienna, Austria The low-density lipoprotein receptor (LDLR) family play key roles in the cellular migration and proliferation in a variety of tissues including arterial wall. LRP-1B (/LR32), is a recently identified membrane protein, and contains 32 LDLR ligand binding repeats, showing the highest homology to LRP among the LDLR family members. In order to know the receptor function in the progression of atherosclerosis, we analyzed the receptor expression in cultured SMCs, and the effects of inhibition of the receptor function on the proliferation and migration of SMCs in vitro. The LRP-1B mRNA and protein were under detectable at the beginning of proliferation, faintly observed in the log-phase period, and drastically induced before the confluent stage of the cultured SMCs. The incubation with anti-LRP-1B antibodies, which competitively inhibit the binding of apo E-rich lipoproteins to the receptor, increased the migration and invasion activities to 1.8- and 2.1- folds of those in control cells in the presence of PDGF. Finally, the immunohistochemical analysis showed that the induced expression of LRP-1B protein in the SMCs localized in the thickened intima as well as media. These results suggest that LRP-1B plays a role in the inhibition of cellular migration and invasion in vitro, possibly contributing the determination of the plaque stability through the inhibitory effects of migration of SMCs in the process of atherosclerosis. 3P-0760 Regulatory mechanism of autosomal recessive hypercholesterolemia (ARH) protein expression E. Abe 1 , M. Ohira 1 , Y. Miyamoto 1 , Y. Asada 2 , M. Harada-Shiba 1 . 1 National Cardiovascular Center Research Institute; 2 Miyazaki Medical College, Japan Background: We have reported on siblings with severe hypercholesterolemia, xanthomas, and premature atherosclerosis without any impairment of LDL receptor in their fibroblasts, as the first clinical characterization of autosomal recessive hypercholesterolemia (ARH), and mutation of ARH was identified in these patients. ARH is thought to be an adaptor protein of LDL receptor, but its function has not been fully understood. In this study, the mechanism of regulation in ARH protein expression was studied in the cultured cells. Materials and Methods: Human skin fibroblasts, vascular endothelial cells, smooth muscle cells and THP-1 cells were used in this study. Lipoprotein deficient serum (LPDS) was obtained from fetal calf serum by ultracentrifu- gation. After the treatment, the cells were collected and subjected to western blot analysis using antibody against C-terminal portion of ARH protein. The bands were detected by the method of ECL. THP-1 cells were stimulated for differentiation by incubation with 50ng/ml of phorbor ester. Results: Significant amounts of ARH protein were detected in fibroblasts, vascular endothelial cells, smooth muscle cells and THP-1 cells. The amount of this protein was not changed in the fibroblasts by preincubation with 10% LPDS or 50 mg/ml of LDL. The amount of the ARH protein expression was not changed after the differentiation of THP-1 cells. Conclusion: The amount of ARH protein expression is stable in several conditions. 3P-0761 Characterization of intermediate density lipoprotein particles that do and do not bind to chondroitin sulphate B. Meyer 1 , L. Duvillard 2 , A. Owen 3 , C. Muriel 4 , C. Packard 4 . 1 Dept. of Biomedical Science, University of Wollongong, NSW, Australia; 2 Laboratory of Biochemistry of Lipoproteins, INSERM, Dijon, France; 3 Smart Foods Centre, University of Wollongong, NSW, Australia; 4 Dept. of Pathological Biochemistry, Glasgow Royal Infirmary, Scotland Objective: The aim of this study was to assess the interaction of IDL particles with chondroitin sulphate (CS) and to characterise the IDL particles that did bind (bound) and did not bind (unbound) to CS. XIIIth International Symposium on Atherosclerosis, September 28–October 2, 2003, Kyoto, Japan