Adma-Plasma-Concentration in Progressive and Stable Glaucoma Patients and Ocular Hemodynamics in Patients With Low and High Adma-Plasma-Levels

Abstract

Purpose: : Asymmetric dimethylarginine (ADMA) has emerged as a novel cardiovascular risc factor and as a possible marker for endothelial dysfunction. Elevated ADMA plasma levels have been detected in several diseases linked to endothelial dysfunction. ADMA acts as an endogenous competitive inhibitor of NO-synthase and causes a decrease in endothelial NO synthesis. The aim of this study was to divide a population of glaucoma patients in stable and progressive course and to determine ADMA-plasma-concentration in both groups and to assess whether there is a difference in ocular hemodynamics in patients with low and high ADMA-plasma levels.

Methods: : 32 glaucoma patients were divided by a standardised blinded schema into a progressive and stable group based on their visual fields (Humphrey 30-2). ADMA-plasma-concentration was determined with enzyme linked immunosorbent assay (ELISA). Mean ADMA-plasma-levels and mean deviation (MD) of both groups were compaired with student's t-test. Color Doppler Imaging (CDI) of retrobulbar vessels (short posterior ciliary artery (SPCA), central retinal artery (CRA) and ophthalmic artery (OA) was performed in 30 patients in standard resting position and during posture change.

Results: : Mean ADMA-plasma-level was 0.54 µmol/L (± 0.11 µmol/L) with a range from 0.37 µmol/L to 0.79 µmol/L. Three glaucoma patients presented a high ADMA-plasma-concentration above the reference value of 0.4 - 0.7µmol/L.MD of patients with stable glaucoma patients was -7.8 ± 6.9, MD of patients with progressive disease was -11.2 ± 7.5 (p=0.18). Mean ADMA-level of stable glaucoma patients was 0.52 ± 0.1, of progressive patients was 0.55 ± 0.1 (p=0.57).As described previously (Galambos P. et al. 2006 Ophthalmology), glaucoma patients showed a decrease of blood flow velocities after posture change from supine to sitting position. Comparing glaucoma patients with high and low ADMA-plasma levels there was no significant difference in retrobulbar blood flow velocities during posture change in highest and lowest quartile (n=14).

Conclusions: : Glaucoma is not associated with generally elevated ADMA-levels and there was no correlation between progression of visual field loss and ADMA-plasma-concentration. Only three of the analyzed patients had ADMA-plasma-concentration above the reference value and two of them had restricted kidney function. Patients with high ADMA-levels showed the same abnormal hemodynamic response to posture change as patients with lower ADMA-levels. This study provides no hint to value ADMA as a risk factor for glaucoma patients.

Keywords: blood supply • visual fields