Incidence of Lipoprotein Lipase Gene Polymorphism and Correlation with Severity of Coronary Artery Disease in Korean

Chung, Joon Yong; Kim, Jung Hee; Lee, Min Soo; Sung, Bo Young; Kim, Yoon Cheol; Kim, Joon Kyung; Ryu, Jung Kon; Sung, In Hwan; Kwon, Gye Cheol; Jeon, Eun Seok

Abstract

BACKGROUND
Lipoprotein lipase(LPL) is a key enzyme in the metabolism of serum triglyceride(TG) which is utilized in the peripheral tissue as free fatty acid and stored in adipose tissue. LPL gene consists of 10 exons which encode 475 amino acids and more than 9 LPL gene polymorphisms have been reported. LPL gene polymorphism is related to lipids level and the severity of atherosclerosis in coronary artery disease. In Korea, LPL polymorphism has not been reported yet. The purpose of this study is to konw the incidences of LPL gene polymorphism and it's relationship with blood lipids level and the severity of atherosclerosis.
METHODS
Subjects were divided into three groups; normal controls(n=50), coronary artery disease(CAD, n=51) and cerebrovascular disease(CVD, n=52). The PCR- amplified genomic DNA from peripheral white blood cell was analyzed with restriction fragment length polymorphism(RFLP) by two different restriction enzymes(Pvu II, Hind III).
RESULTS
Total cholesterol(TC) was higher in CVD than in controls and CAD (203+/-60mg/dl vs 188+/-37, 167+/-42, p<0.01). Triglyceride(TG) was also elevated in CAD(166+/-65mg/dl vs 122+/-62 in controls, p<0.05). HDL cholesterol(HDL-C) was higher in controls than in CVD and CAD(49+/-9mg/dl vs 36+/-10, 44+/-9, p<0.05). The incidence of Hind III RFLP and Pvu II RFLP was not different among groups. There was no correlation between LPL gene RFLP and lipid profile. There was no correlation between LPL gene RFLP and severity of coronary arterial stenosis. The incidence of Hind III RFLP (-/-) homozygotes was lower in Korean than in other country(5% vs 7-10%). The incidence of Pvu II RFLP (-/-) homozygotes was lower in Korean than in other country(10.3% vs 18-29%).
CONCLUSIONS
The LPL gene mutations in intron 6 and 8 have no direct effects on the lipid profiles and the severity of coronary artery disease. Although LPL is a key enzyme in TG metabolism, two mutations in this study could not change the activity of LPL, nor were a marker linked to other site of mutation(s). The mutation(s) in exon which encode amino acid for enzyme activity should be detected to dissect the pathphysiologic mechanism in the atherogenesis.