ABSTRACT
Atherosclerosis is a complex disease caused by both genetic and environmental factors. Apolipoprotein E polymorphism is believed to confer substantial susceptibility to coronary heart disease risk. This study was performed on sixty five males selected with normal serum glucose, kidney function, liver function and thyroid function tests. They were classified into: Group A: Apparently healthy individuals [40 subjects], with normal blood pressure and ECG. Group B: Patients with atherosclerotic coronary artery disease [CAD] diagnosed by coronary angiography [25 cases]. All the studied persons were subjected to: serum lipogram, apolipoprotems A-I, B and E concentration and apolipoprotein E genotyping. In CAD group, the mean values of serum total cholesterol triglycerides, LDL-c, TC / HDL-c ratio, LDL-c / HDL-c ratio, apolipoprotein B concentration and apo B /A-I showed significant elevation while HDL-c levels revealed significant reduction compared to apparently healthy group. In CAD group, apo E 3/3 represented 68% of cases, followed by apo E 3/4 genotype 24%, apo E 3/2 genotype 4% and the homozygous apo E 2/2 genotype 4%. In apparently healthy group, apo E 3/3 genotype represented 70%, apo E 3/4; 12.5% and apo E 3/2; 17.5% of the studied individuals. CAD patients carrying apo E 3/3 genotype, had elevations of serum triglycerides, total cholesterol, LDL-c apo B and apo B/A-I ratio in 6%, 47%. 71%, 35% and 12% of cases [respectively] while HDL-c was reduced in 65% of cases carrying this genotype compared to the levels in apparently healthy group. Average risk values of TC/HDL-c ratio were found in 65% of cases and moderate risk values in 35% of cases. High risk values of LDL-c/HDL-c ratio were found in 18% of cases and moderate values in 82% of cases. But carriers of apo E 3/4 genotype in CAD patients had elevated triglycerides, total cholesterol in 33%, 67% of cases respectively and in LDL-c, apo B and apo B/A-I ratio in 83% of cases while HDL-c and apo A-I were reduced in 83% and 67% of cases carrying this genotype respectively. High risk values of TC/HDL-c and LDL-c/HDL-c ratios were observed in 17% and 18% of cases respectively. Other genotype carriers [E3/2 and E2/2] showed no difference when compared to the levels in apparently healthy subjects. In apparently healthy group, apo E 3/4 genotype carriers had significant elevation of serum TC, TG, LDL-c, TC/HDL-c ratio, LDL-c/HDL-c ratio, apo B and apo B/A-I ratio and significant reduction of apo A-I and E concentration than apo E 3/3 genotype carriers. Carriers of E 3/4 genotype also had significant elevation of TC, LDL-c, apo B and apo B/A-I ratio and significant reduction of apo E concentration compared to those carrying apo E 3/2 genotype. 1-Apo E 3/3 is the most common genotype in both apparently healthy subjects and atherosclerotic CAD patients. If is followed by apo E 3/2, then apo E 3/4 genotypes in apparently healthy group, and followed by apo E 3/4, then apo E 3/2 and apo E 2/2 in CAD group. None of the studied individuals had either apo E 4/4 or apo E 2/4 genotypes. 2 -Apolipoprotein E 3/4 genotype carriers had elevated levels of serum total cholesterol triglycerides, LDL-c, apolipoprotein B A apo B/A-I ratio, and reduced levels of HDL-c and apo A-I.So, they are susceptible to more atherogenic lipid profile than other genotype carriers, which is considered a predisposing factor for atherosclerotic coronary artery disease. As regard TC/HDL-c and LDL-c/HDL-c ratios, most of the patients carrying apo E3/4 genotype had high and moderate risk values while patients carrying apo E 3/3 genotype had average and moderate risk values