The Study of Serum Asymmetric Dimethylarginine Concentrations in the Different Paraoxonase Phenotypes of Exudative Age-related Macular Degeneration Disease

Age-related macular degeneration (ARMD) is a degenerative retinal disorder that causes progressive loss of central vision in older adults. The study aimed to determine the effect of asymmetric dimethylarginine (ADMA) as oxidizing metabolite and paraoxonase (PON1) activity within its phenotypes as an antioxidant agent in the development of such multifactorial disease.

Forty-five exudative ARMD (E-ARMD) patients and 45 healthy controls were enrolled for this case-control study. Serum PON1 activity was measured using paraoxon and phenylacetate as substrates. PON1 phenotype was determined using the double-substrate method. The ADMA and oxidized LDL (OX-LDL) levels were determined by enzyme-linked immunosorbent assay method. Blood lipid profile was measured, and nontraditional lipid indexes were calculated.

Three phenotypes were determined for PON1 among the participants in the study, including AA, AB, and BB phenotypes with low, moderate, and high activity, respectively. AA phenotype was more frequent among E-ARMD, while AB and BB phenotypes were more common among healthy subjects. The mean ADMA and OX-LDL levels were significantly higher in the patients comparing to the controls (p=0.02 and p=0.01, respectively). No significant differences were found in ADMA and OX-LDL levels between phenotypes in each group and also among similar phenotypes. LDL, cholesterol, and even all comprehensive lipid indexes except (atherogenic index of plasma) were higher in E-ARMD patients compared with the healthy group.

It was concluded that high-risk individuals could be identified by evaluating the blood factors involved in oxidative stress, and antioxidant therapies may reduce the incidence and progression of the disease.