Role Of NPC1L1 Gene And Its V55L Polymorphism In The Artherosclerosis

Background and Objectives:Atherosclerosis affects 79.9%of the adult population with age more than 60 year old,which makes it an important project.There is a close relationship between atherosclerosis and blood lipid,both hyperlipemia and hype rcholes teremia are major risks of atherosclerosis.As compared with hyperlipemia, hypercholesteremia plays a much more important role.Therefore,the intervention of cholesterol absorption or metabolic pathway might be an alternative method for prevention of atherosclerosis.Previous study shows that Niemann-Pick C1 like1(NPC1L1) gene plays an important role on the cholesterol absorption in the enteric epithelium;moreover,the NPC1L1 gene is also a target of cholesterol absorption inhibitor(ezetimibe).Based on the above-mentioned evidences,it's reasonable to prospect the cholesterol absorption inhibitor would take more and more important position in the prevention of atherosclerosis and the cardiovascular disease in the future.The genetic cause(s) of coronary atherosclerotic heart disease(CHD) has been difficult to decipher.It is likely that in any CHD individual,more than one effector gene is engaged in a complex network of gene-gene and gene-environment.More and more studies are focusing on the relationship between CHD and gene polymorphisms.Due to the important role of lipid metabolic disorder on CHD and atherosclerosis,more research studies are working on the gene polymorphisms related with lipid metabolic disorder.To check the role of NPC1L1 on CHD and atherosclerosis,we examined the expression NPC1L1 mRNA in intestines from rats with hyperlipemia and atherosclerosis in this study;moreover,we also investigated the V55L gene polymorphism in patients with CHD and lipid metabolic disorder to uncover the role of V55L in Chinese patients.Subjects and MethodsSubjects1.The health Wistar male rats,with weight 250±50g,were randomly divided into three groups.Each group had 10 rats.The hyperlipemia rats and atherosclerostic rats were used in this study,the control rats were fed with normal rat food.2.The patients with Atherosclerosis in our hospital from May to November in 2005 and other patients without CHD or other cardiovascular diseases,including 129 cases with CHD and 107 cases without CHD,among whom 147 are male and 89 are female ranging from 41 to 72(56.1+12.6).Patient with CHD have been conformed according to the CHD diagnosis standards published in 1981 with 29 cases conformed by coronary arteriongraphy.Methods1).Animal study1.Hyperlipemia rat model was established by feeding the rat with high fat food, atherosclerostic rat model with high fat food together with intraperitoneal injection of vitamine D,the control rats with normal rat food.2.The aortas and coronary arteries and serum biochemical examinations were examined in all three groups.3.The expressions of the NPC1L1 mRNA were investigated by semi-quantitative RT-PCR method.4.Statistical analysis was done to check the differences of NPCIL1 mRNA expressions among three groups.2) Clinical study1.Serum biochemical examinations were investigated in 129 CHD patients and 107 controls.2.Two hundred and thirty-six clinical samples were checked by RT-PCR.3.The NPC1PL1 gene was amplified by restriction enzyme method.4.DNA sequencing was checked in this study.Results1) Animal study1.Pathologic results:Atheromatous plaques were found in 14 week-old rats in atheromatous rats,not in hyperlipemia rats and control rats.2.Biochemical results:As compared with control rats,the levels of TC,TG,and LDL-C were higher;the level of HDL-C was lower in atherosclerostic rats and hyperlipemia rats.There was no significant difference between atherosclerostic rats and hyperlipemia rats.3.Gene analysis:There were NPC1L1 gene expressions in small intestines from all three animals.As compared with control rats,the levels of NPC1L1 gene expressions in small intestines were higher in atherosclerostic rats and hyperlipemia rats.There was no significant difference between atherosclerostic rats and hyperlipemia rats.2) Clinical study1.Biochemical results:The levels of HDL-C were lower in CHD patients than controls; with respect to TG,TC,LDL-C,ApoA and ApoB,there were no differences.2.Gene analysis:All three V55L polymorphisms were checked by PCR-RFLP method in our selected patients.Only VV type(no polymorphism) was found in those Chinese patients,ConclusionThe animal study1.The atherosclerostic rat models are established by feed with high fat food together with intraperitoneal injection of vitamine D.2.With regard to TC,TG,HDL-C and LDL-C,there are significant differences in atherosclerostic rats and hyperlipemia rats as compared with control rats,in contrast,no differences between atherosclerostic rats and hyperlipemia rats.3.The high expression of NPC1L1 in small intestines,which accelerates the cholesterol absorption,plays an important role on serum lipid disorder.4.The NPC1 L1 expression is higher in atherosclerostic rats than controls.However, there is no significant difference between atherosclerostic rats and hyperlipemia rats.The role of NPC1 L1 on atherosclerosis needs to be checked in the further study.Clinical research1.The serum HDL-C levels are lower in CHD patients than controls.The low level of HDL-C leads to a serious consequence in CHD patients.2.There is no V55L polymorphism in our selected patients.