Significant Variation of the Elevated Nitric Oxide Levels in Aqueous Humor from Patients with Different Types of Glaucoma
ABSTRACT Though several studies have shown that the biochemical function of nitric oxide (NO) in the eye might play an important role in the regulation of intraocular pressure (IOP), local control of ocular blood flow and loss of retinal ganglion cells by apoptosis, it is unclear whether the role of NO is similar in the pathogenesis of different kinds of glaucoma: primary open-angle glaucoma (POAG), chronic closed-angle glaucoma (CCAG) and neovascular glaucoma (NVG). To further explore this issue, we measured the concentrations of NO in aqueous humor and plasma samples from patients with POAG (n = 31), CCAG (n = 76), NVG (n = 8) and cataract (n = 30). All of the NVG patients suffered from severe proliferative diabetic retinopathy, while other patients were free of any other systemic disease. The NO levels in both aqueous humor and plasma samples were assessed by chemiluminescence assay. We found that the NO levels in aqueous humor samples were greatly varied in patients with POAG (36.2 +/- 3.3 microM), CCAG (47.7 +/- 3.4 microM) and NVG (65.8 +/- 5.4 microM), and all of them were significantly higher than in cataract patients (27.0 +/- 2.9 microM p < 0.05). Except NVG patients whose NO levels in plasma samples were highest (24.1 +/- 3.5 microM) among all groups, the plasma NO levels were not significantly different between the other glaucoma patients and the cataract patients. We therefore concluded that significant variation of the elevated NO levels in aqueous humor samples from the patients with different types of glaucoma may reflect their differences in the pathogenesis.
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- "Significant quantities of NOS-2 have been detected in the astrocytes and microglia at optic nerve head of glaucoma patients. Elevated NO levels have been observed in the aqueous humor of glaucoma patients and a genetic association of iNOS and POAG has also been observed. The animal experiments have also shown an association of elevated ocular NO levels with RGC death. "
ABSTRACT: Glaucoma, the second leading cause of blindness, is characterized by changes in the optic disc and visual field defects. The elevated intraocular pressure was considered the prime factor responsible for the glaucomatous optic neuropathy involving death of retinal ganglion cells and their axons. Extensive investigations into the pathophysiology of glaucoma now reveal the role of multiple factors in the development of retinal ganglion cell death. A better understanding of the pathophysiological mechanisms involved in the onset and progression of glaucomatous optic neuropathy is crucial in the development of better therapeutic options. This review is an effort to summarize the current concepts in the pathophysiology of glaucoma so that newer therapeutic targets can be recognized. The literature available in the National Medical Library and online Pubmed search engine was used for literature review.Indian Journal of Ophthalmology 03/2009; 57(4):257-66. DOI:10.4103/0301-4738.53049 · 0.93 Impact Factor
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ABSTRACT: Multiple biomarker panels of common, multifactorial diseases - such as cardiovascular and Alzheimer’s disease - have recently been described, facilitating the diagnosis and risk management of these diseases. In principle, a biomarker is an indicator of a biochemical feature or facet that can be used to diagnose or monitor the progress of a disease. Detection technology has been identified for possible types of biomarkers in primary open-angle glaucoma (POAG). We will summarize known biomarkers with the intent of cataloging the biomarkers in the aqueous humor, trabecular meshwork (TM), optic nerve, and blood in patients with POAG. To facilitate comparisons and to offer mechanistic clues, biochemical changes such as up- or downregulation of proteins that have been reported in POAG are organized into three categories: namely, extracellular matrix (ECM) changes, cytokine/signaling molecules, and aging/stress (listed respectively in Tables 82.1, 82.2, and 82.3).
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ABSTRACT: Abnormal nitric oxide (NO) synthesis has been implicated in the pathogenesis of diabetes mellitus. The aim of our study was to elucidate the relationship between the stages of diabetic retinopathy (DR) and the NO levels in aqueous humor and plasma. Using the chemiluminescence assay, we measured the concentrations of NO in aqueous humor and plasma samples obtained during intraocular surgery from 45 diabetic patients and 19 nondiabetic cataract patients. The patients with diabetes were classified into 4 groups: proliferative DR (PDR) with active neovascularization (active PDR; 9 cases), PDR with quiescent neovascularization (regressed PDR; 6 cases), background DR (BDR; 16 cases) and no DR (14 cases). We found that the aqueous NO levels (mean +/- SE) of the active PDR group (83.2 +/- 13.9 microM) were significantly higher than those of the BDR group (45.8 +/- 6.0 microM, p = 0.049) and the diabetics without DR (33.3 +/- 5.2 microM, p = 0.011), and, although not statistically significantly, they were also higher than those of the regressed PDR group (52.1 +/- 10.3 microM, p = 0.224). However, no significant differences were observed between any of the diabetic subgroups in the plasma NO levels (p = 0.345). We therefore concluded that NO present in the ocular tissues may play important roles in the progression of DR.Ophthalmologica 09/2003; 217(5):342-6. DOI:10.1159/000071349 · 1.87 Impact Factor