Increased Homocysteine Levels in Tear Fluid of Patients with Primary Open-Angle Glaucoma

Abstract

Aims: We assessed homocysteine (Hcy) levels in tear fluid and plasma of patients with primary open-angle glaucoma (POAG). We determined the association between Hcy levels, dry eye syndrome and B vitamin status. Methods: This prospective case-control study included 36 patients with POAG and 36 controls. Hcy concentrations were measured by high-performance liquid chromatography. Results: Patients with POAG had significantly higher mean Hcy levels both in tear fluid (205 ± 84 nmol/l; p < 0.001, t test) and in plasma (13.43 ± 3.53 µmol/l; p = 0.001, t test) than control subjects (130 ± 53 nmol/l and 10.50 ± 3.33 µmol/l, respectively). Hcy in tear fluid was significantly correlated with plasma Hcy in POAG patients (r = 0.459; p = 0.005, Pearson’s correlation), but not in controls (r = 0.068; p = 0.695). POAG patients with dry eye disease had significantly higher Hcy levels both in tear fluid and plasma than POAG patients without dry eye disease. There was no association between Hcy levels and B vitamin status in subjects with POAG. Conclusions: The study suggests increased Hcy levels in tear fluid and plasma of patients with POAG. Elevated Hcy levels might be a risk factor for POAG and dry eye syndrome in subjects with glaucoma.

Two dimensional electrophoretic analysis of human tears: Collection method in dry eye syndrome

“…The detection of various factors such as lipids [31], growth factors, proteases and cytokines [32] and small molecules such as homocysteine [33] and antioxidants [34] apart from various proteins is supportive of the fact that tear can be a potential specimen for diagnostics and prognostics. Differentially expressed proteins in tear characteristic of the clinical condition especially in corneal disorders are getting reported [23,[35][36][37][38].…”

Lack of Association between Serum Vitamin B6, Vitamin B12, and Vitamin D Levels with Different Types of Glaucoma: A Systematic Review and Meta-Analysis

“…Although many publications have reported a difference in serum vitamin levels between patients with glaucoma and normal subjects, the association between serum vitamin levels and glaucoma in humans remains controversial. Turgut et al [6] showed that the serum vitamin B 6 levels are significantly higher in POAG and NTG patients than in controls, but others reported no significant difference in serum vitamin B 6 levels among these groups [7,8,9]. Several studies have shown that serum vitamin B 12 levels are elevated in NTG, POAG, and EXG [6,10,11], but others have reported decreased levels of serum vitamin B 12 [9,12].…”

Plasma Homocysteine Levels in Patients With Normal Tension Glaucoma

“…The excitatory amino acid homocysteine (Hcy) is a neurotoxin that can induce typical pathologic changes seen in glaucomatous neuropathy such as apoptosis of retinal ganglion cells, 9 extracellular matrix changes, 10 oxidative stress, 11 and vascular dysregulation. 12 Conclusive evidence has already been provided that Hcy levels in plasma, aqueous humor, and tear fluid are elevated in patients with primary open-angle glaucoma and pseudoexfoliation glaucoma [13][14][15][16][17][18][19][20][21][22] and Hcy has been suggested as a possible risk factor in the development of those highpressure glaucoma types.…”