Evaluation of asymmetric dimethylarginine and oxidative stress in patients with coronary artery disease

SUMMARYAtherosclerotic coronary artery disease is a major public health issue worldwide. Endothelial dysfunction is the harbinger of atherosclerosis and many inflammatory and oxidative pathways interact in an elaborate fashion, culminating in full-blown atherosclerotic coronary artery disease.Asymmetric dimethylarginine (ADMA) seems to cause damage to the vascular bed by decreasing nitric oxide (NO) levels and increasing super oxide levels. Oxidized LDL (Ox-LDL) not only induces the PMRT enzyme which catalyzes the synthesis of ADMA, but inhibits the DDAH enzyme which catalyzes the breakdown of ADMA as well. Resultantly, Ox-LDL decreases NO levels by increasing ADMA. Ox-LDL is formed during the lipid peroxidation process, and measurement of MDA levels in biological materials is used as a surrogate of lipid peroxidation.In subjects with normal coronary arteries, mild atherosclerotic coronary artery disease, and severe atherosclerotic coronary artery disease, serum ADMA and SDMA levels were determined using the HPLC method (Eureka Kit). Ox-LDL levels were determined using the ELISA method (Immundiagnostic kit). MDA levels were determined by using the HPLC method (Immuchrom Kit) and the spectrophotometric method separately.According to our results, there was no statistically significant difference between the normal coronary arteries group, minimal coronary artery disease group, and the severe coronary artery disease group with regard to ADMA, SDMA, Ox-LDL, and MDA levels (p>0,05). The fact that total cholesterol and LDL-cholesterol levels are low in severe CAD group has been attributed to the higher incidence of statin use in this group.Statins, which efficiently lowered serum lipid levels in the severe CAD group, may have lowered the ADMA levels as well. Lowering of ADMA levels by statins may result in alleviation of the damage to the vascular wall caused by ADMA. This hypothesis needs to be tested in larger scale studies.