Precis: Apelin and asymmetric dimethylarginine (ADMA) concentrations, affecting the nitric oxide pathway, were different in the patient group compared with the control subjects. These 2 molecules may have potential effects in vascular pathologies and their possible role in predisposition to vascular comorbidities in exfoliation syndrome (XFS) or exfoliative glaucoma (XFG). Purpose: To evaluate apelin and ADMA levels in serum samples from patients with XFS or XFG compared with healthy control subjects. Methods: Serum ADMA and apelin concentrations were evaluated from 36 and 32 XFS patients; 27 and 24 XFG patients; and 34 and 30 healthy controls, respectively. Subjects without systemic disease (including diabetes mellitus, hypertension, coronary artery disease, obesity) were included in the study and body mass index was calculated in all participants. An enzyme-linked immunosorbent assay and high-performance liquid chromatography were used to determine serum apelin and ADMA concentrations. Independent samplettest, chi(2)test, analysis of variance test, and Pearson test were used for statistical analysis. Results: Mean serum apelin levels of XFG, XFS, and control group were 1063.3 +/- 373.4, 1196.7 +/- 433.7, and 1343.3 +/- 405.1 ng/mL, respectively. Patients with XFG demonstrated significantly lower level of apelin versus controls (P=0.034). Mean serum ADMA concentration was significantly greater in XFS subjects (2.05 +/- 0.98 mu mol/L) compared with normal controls (1.57 +/- 0.58 mu mol/L) (P=0.042). No association was detected between ADMA and apelin concentrations and age, sex, and body mass index for both XFS and XFG groups. Conclusions: Significant alterations in serum levels of apelin and ADMA may suggest potential effects in vascular pathologies and a possible role in predisposition to vascular comorbidities in XFS/XFG.