engleski

The relation of apo E genotypes, lipids and apolipoproteins for coronary heart disease in middle-aged women

Apolipoprotein E (apoE) is a major component of triglycerides-rich lipoprotein and represents plasma protein that modulates the metabolism of apolipoprotein B (apoB). This protein is associated with HDL cholesterol and serves as a ligand for the LDL receptor, or actually the LDL receptor related protein. ApoE synthesizes primarily in the liver. Three common alleles have been identified: E2, E3 and E4, determined by the six apolipoprotein E phenotypes ; E 2/2, E 2/3, E 2/4, E 3/3, E 4/3, E 4/4. ApoE genotype may be involved in development of coronary heart disease (CHD). It is well known that subjects with the apoE4 allele represent persons with an increased risk for CHD, but association of apo E gene polymorphism and CHD is not consistent. The gene for apoE is located in chromosome 19 in a cluster with the apoC-I and apoC-II genes. In our study apoE genotypes and plasma metabolic risk factors were determined in 134 healthy middle-aged (XąSD 49, 62ą4, 83) women. The aim of this study was to investigate metabolic risk markers ; total cholesterol, triglycerides, HDL and LDL cholesterol, total/HDL cholesterol ratio, lipoprotein Lp(a), apolipoprotein A-I, A-II, apoB, and apoE according to various apoE genotypes, and to evaluate a possible risk for coronary heart disease. The results revealed that the frequencies of apo E3/3 are the most frequent (46%), followed by E4/4 (2%), E3/4 (14%), E2/3 (14%), and E2/4 (2%). Higher mean triglycerides, LDL-C and apoB levels were found with apoE3/4, and lower mean levels of HDL-C, i.e. apo A-I than in other analyzed genotypes. Greater mean of total/HDL ratio and lower levels of apo A-II were seen with E2/4. Serum lipoprotein Lp(a) concentration was higher in women with genotypes E3/3. Apo E concentration was the lowest with genotypes E4/4, i.e. the highest with E2/3. Serum total cholesterol tended to be higher in women with genotypes E4/4. Genotype E314 is connected with highest concentrations of (XSąD) triglycerides (1, 74ą 0, 78), LDL (4, 28ą1, 88), apoB (1, 03ą0, 32) and with lowest concentrations of HDL cholesterol (1, 11 ą0, 21 ) in relation to other analyzed genotypes. This group of women could possibly represent high risk women for CHD. Genotype E3/3 is associated with the highest concentration of independent genetic risk marker for CHD, lipoprotein Lp(a) (0, 19ą0, 27). The genotype E4/4 has the highest concentration of total cholesterol (5, 93ą1, 01 ), and has to be taken in account for risk evaluation in women. High level of apoE (0, 1 1 ą0, 05) and low level of apo A-I ( 1, 80ą0, 44) were associated with E2/3 genotypes. The significance of E3/4 with the high total/HDL ratio (5, 52ą2, 21) and low apo A-II (0, 53ą0, 09) is an important indicator, because total/HDL cholesterol ratio represents independent Established Risk Factor (ERF) for CHD. Conclusion: Apolipoprotein E genotypes as a genetic marker in correlation with changes in serum metabolic risk markers play an important role in determining quantitative risk factors for coronary heart disease among middle-aged healthy women.

apo E genotypes; lipids; apolipoproteins; coronary heart disease; anthropology; population genetics

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