Asymmetric dimethylarginine is not elevated in exfoliation syndrome but symmetric dimethylarginine is related to exfoliative glaucoma

Association Between the Asymmetric Dimethylarginine Levels and Glaucoma Severity: A Cross-Sectional Analysis of the LIGHT Study

Purpose

Asymmetric dimethylarginine (ADMA), a potent endogenous inhibitor of nitric oxide synthase, may be involved in the pathophysiology of glaucoma by dysfunctioning nitric oxide and oxidative stress. The purpose of this study was to determine whether the serum ADMA level is associated with the severity of glaucoma.

Methods

One hundred twenty-five patients with glaucoma (mean age 69.4 years) were analyzed in this cross-sectional study. The severity of glaucoma was determined by the visual field mean deviation in the worse eye; severe, a mean deviation ≤ -12 dB; and mild, a mean deviation > -12 dB. The serum ADMA levels were classified into three groups according to tertiles; low (T1), intermediate (T2), and high group (T3).

Results

The mean serum ADMA levels in the severe glaucoma group was significantly higher than that in the mild glaucoma group (0.41 vs. 0.39 µmol/L; P = 0.031). A significantly higher prevalence of patients with severe glaucoma was found in the T3 group than that in the T1 group (T1, 44.7% and T3, 68.2%; P = 0.018). In the multivariable logistic regression analysis adjusted for the potential confounders, e.g., age, sex, obesity, smoking, hypertension, diabetes, and renal function, the odds ratio for severe glaucoma in the T3 group was significantly higher than that in the T1 group (odds ratio 3.02; 95% confidence interval 1.04 to 8.79; P = 0.043).

Conclusions

A significant association between higher serum ADMA levels and severe glaucoma was found, and this association remained significant after adjusting for the potential confounders.

Serum Apelin and Asymmetric Dimethylarginine Levels in Patients With Exfoliation Syndrome or Exfoliative Glaucoma

PRéCIS:: 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 sample t test, χ 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 µmol/L) compared with normal controls (1.57±0.58 µmol/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.

Increased Aqueous Humor Symmetric Dimethylarginine Level in Patients with Primary Open Angle Glaucoma

Purpose: To evaluate the asymmetric dimethylarginine (ADMA), symmetric dimethylarginine (SDMA) and L-arginine (L-Arg) levels both in plasma and aqueous humor of primary open angle glaucoma (POAG) patients and matched controls. Patients and Methods: 25 primary open angle glaucoma patients and 42 control cases with senile cataract were included in the study. Plasma and aqueous humor ADMA, SDMA and L-Arg levels of the participants were measured by using liquid chromatography-tandem mass spectrometry. Results: A significant increase in aqueous humor SDMA level was detected in POAG patients compared with controls (p = 0.0115). No significant difference was detected in plasma and aqueous humor ADMA, L-Arg levels. Conclusion: The aqueous humor levels of SDMA are found to be associated with POAG. The result of this current study supports the role of nitric oxide pathway in glaucoma.

Recent advances in the applications of metabolomics in eye research

Metabolomics, the identification and quantitation of metabolites in a system, have been applied to identify new biomarkers or elucidate disease mechanism. In this review, we discussed the application of metabolomics in several ocular diseases and recent developments in metabolomics regarding tear fluids analysis, data acquisition and processing.

Nailfold capillary morphology in exfoliation syndrome

PurposeThe purpose of the study was to investigate nailfold microvascular morphology in exfoliation syndrome with or without glaucoma (XFS/XFG) compared with primary open-angle glaucoma (POAG) and control subjects using nailfold capillary videomicroscopy.Patients and methodsWe used a JH-1004 capillaroscope to perform nailfold capillary videomicroscopy on the fourth and fifth digit of the non-dominant hand. We enrolled 56 XFS/XFG patients, 87 POAG patients, and 75 control subjects. Masked observers graded the videos for hemorrhages, avascular zones ≥200 microns (μm), and degree of microvascular tortuosity on a four-point subjective scale. Multivariable odds ratios, 95% confidence intervals and P-for trends for assessing the relation between morphological changes and POAG or XFS/XFG were obtained from logistic regression analyses. We also assessed this relation with XFS/XFG compared with POAG in multivariable models.ResultsAfter adjusting for multiple covariates, nailfold hemorrhages, avascular zones ≥200 μm, and higher degree of vascular tortuosity were more common in XFS/XFG vs controls (P-for trend ≤0.0001) and in POAG vs controls (P-for trend ≤0.01). For each 100 capillaries, the number of hemorrhages was similar (P-for trend=0.91) between XFS/XFG and POAG patients; however, there were more avascular zones per 100 capillaries with borderline significance (P-for trend=0.04) in the XFS/XFG group. XFS/XFG patients had more tortuosity than POAG patients; specifically, having a tortuosity score ≥1.5 was associated with a 4.4-fold increased odds of XFS/XFG (95% confidence interval: 1.5-13.3) relative to a tortuosity score <1.0 (P-for trend=0.005).ConclusionA high degree of nailfold capillary tortuosity is a distinct non-ocular feature associated with XFS/XFG compared with either POAG or controls.

[Diagnosis and therapy of pseudoexfoliation glaucoma]

Pseudoexfoliation (PEX) glaucoma is the most frequent and most important type of secondary glaucoma, accounting for approximately 25% of open angle glaucoma worldwide and currently representing the most common identifiable cause of glaucoma overall. Due to high intraocular pressure levels, marked diurnal pressure fluctuations and spikes, and rapid optic nerve damage and visual field loss, PEX glaucoma represents a relatively severe and progressive type of glaucoma. Therefore, hard and fast lowering of intraocular pressure is necessary. Fixed combinations in medical therapy and early glaucoma surgery are recommended. When considering a surgical procedure (e.g. selective laser trabeculoplasty, bleb-dependent or bleb-independent surgery) the timing of cataract surgery plays a major role. Pathogenesis, clinical characteristics and therapeutic aspects of PEX glaucoma are described in the following article.