cyclic-gmp and Glaucoma--Open-Angle

The nitric oxide (NO)-cyclic guanosine-3',5'-monophosphate (cGMP) pathway regulates aqueous humor outflow and therefore, intraocular pressure. We investigated the pharmacologic effects of the soluble guanylate cyclase (sGC) stimulator IWP-953 on primary human trabecular meshwork (HTM) cells and conventional outflow facility in mouse eyes.. Cyclic GMP levels were determined in vitro in HEK-293 cells and four HTM cell strains (HTM120/HTM123: predominantly myofibroblast-like phenotype, HTM130/HTM141: predominantly endothelial-like phenotype), and in HTM cell culture supernatants. Conventional outflow facility was measured following intracameral injection of IWP-953 or DETA-NO using a computerized pressure-controlled perfusion system in enucleated mouse eyes ex vivo.. IWP-953 markedly stimulated cGMP production in HEK-293 cells in the presence and absence of DETA-NO (half maximal effective concentrations: 17 nM, 9.5 μM). Similarly, IWP-953 stimulated cGMP production in myofibroblast-like HTM120 and HTM123 cells, an effect that was greatly amplified by the presence of DETA-NO. In contrast, IWP-953 stimulation of cGMP production in endothelial-like HTM130 and HTM141 cells was observed, but was markedly less prominent than in HTM120 and HTM123 cells. Notably, cGMP was found in all HTM culture supernatants, following IWP-953/DETA-NO stimulation. In paired enucleated mouse eyes, IWP-953 at 10, 30, 60, and 100 μM concentration-dependently increased outflow facility. This effect (89.5%) was maximal at 100 μM (P = 0.002) and in magnitude comparable to DETA-NO at 100 μM (97.5% increase, P = 0.030).. These data indicate that IWP-953, via modulation of the sGC-cGMP pathway, increases aqueous outflow facility in mouse eyes, suggesting therapeutic potential for sGC stimulators as novel ocular hypotensive drugs.

Topics: Adult; Animals; Aqueous Humor; Cells, Cultured; Child, Preschool; Cyclic GMP; Disease Models, Animal; Enzyme Inhibitors; Glaucoma, Open-Angle; Guanylate Cyclase; Humans; Infant; Intraocular Pressure; Mice; Mice, Inbred C57BL; Trabecular Meshwork

To investigate the levels of nitric oxide (NO) markers in plasma and aqueous humour of patients with primary open angle glaucoma (POAG) and their relation to ocular perfusion pressure.. Cyclic guanosine monophosphate (cGMP) and nitrite (NO(2)(-)) were determined in plasma and aqueous humour of 38 patients with POAG and 46 controls. Blood pressure and IOP were measured to calculate ocular perfusion pressure (PP).. cGMP and NO(2)(-) plasma levels were significantly decreased in glaucoma patients compared with controls (p = 0.001 v p = 0.004). In the aqueous humour of subjects with POAG, cGMP and NO(2)(-) concentrations were also lower than in normal eyes (p = 0.0001 v p = 0.001). There was a linear association between cGMP in plasma and aqueous humour in glaucomas and controls (r = 0.514, p = 0.029 and r = 0.558, p = 0.004) and this relation differed in the two groups (p = 0.003). Considering glaucoma patients with controls, a positive correlation was found between cGMP and PP (r = 0.379, p = 0.01) and between NO(2)(-) and PP (r = 0.339, p = 0.040). The cGMP/PP correlation was of borderline statistical significance in controls (p = 0.050), whereas it did not attain statistical significance in POAG, as well as the association between NO(2)(-) and PP when glaucomas and controls were considered separately.. The authors found alterations of NO markers in the plasma and aqueous humour of glaucoma patients. Primary or secondary impaired NO balance could alter ocular perfusion pressure.

Topics: Aged; Aqueous Humor; Biomarkers; Case-Control Studies; Chemotherapy, Cancer, Regional Perfusion; Cyclic GMP; Female; Glaucoma, Open-Angle; Humans; Intraocular Pressure; Male; Middle Aged; Nitric Oxide; Nitrites

The authors studied the ocular haemodynamics by means of the Color Doppler Imaging (CDI) technique and the levels of cyclic guanosine monophosphate (cGMP), the intracellular mediator of NO action in plasma and the aqueous humour in a Normal Pressure Glaucoma group and in a normal group. They found significant alterations of both the velocities, systolic and diastolic, in the Ophthalmic Artery and lower cGMP levels in NPGs than in the controls. These data suggest that a disorder of NO regulation processes might be involved in blood supply to the optic nerve and in aqueous humour outflow.

Topics: Aged; Aqueous Humor; Blood Flow Velocity; Ciliary Arteries; Cyclic GMP; Female; Glaucoma, Open-Angle; Humans; Intraocular Pressure; Male; Middle Aged; Nitric Oxide; Ophthalmic Artery; Ultrasonography, Doppler, Color

Cells isolated from the trabecular meshwork (TM) of a male glaucoma patient were transformed by transfection with an origin defective mutant of SV40 virus. Transformation dramatically increased the growth rate of these cells (designated HTM-3 cells), allowing biochemical and pharmacological characterization. The HTM-3 cells had cytoskeletal components that were reported to be present in TM tissue and non-transformed TM cells. Vimentin, tubulin and smooth muscle specific alpha-actin, but not desmin, were localized in these cells by immunocytochemistry. The extracellular matrix components collagen types I, III and IV, fibronectin and laminin were found in HTM-3 cells as well as their non-transformed parental cells. As predicted, the protein profile of the HTM-3 cells revealed by two-dimensional gel electrophoresis was different from that of the non-transformed cells, probably due to the enhanced growth characteristics of these cells. Furthermore, HTM-3 cells had various intracellular second messenger systems that responded to pharmacological agents. Forskolin, prostaglandin E2, beta-adrenergic and adenosine A2 agonists stimulated the adenylyl cyclase in these cells, whereas muscarinic, serotonergic, dopaminergic and other agonists were ineffective. Sodium nitroprusside increased the intracellular concentration of cGMP, demonstrating the presence of a functional guanylyl cyclase. Phospholipase C activity in these cells was also detected. Muscarinic agonists, histamine and bradykinin, but not adrenergic, serotonergic agonists or prostaglandins, increased phosphoinositide turnover. These drug responses of HTM-3 cells agree with published data on primary TM cells and TM tissues, suggesting that the transformed cells may be a valid substitute for certain pharmacological studies of TM.

Topics: Aged; Cell Division; Cell Transformation, Viral; Cells, Cultured; Cyclic GMP; Cytoskeletal Proteins; Extracellular Matrix Proteins; Glaucoma, Open-Angle; Humans; Male; Second Messenger Systems; Simian virus 40; Trabecular Meshwork; Transfection; Type C Phospholipases

Topics: Adolescent; Adult; Aged; Alkaloids; Animals; Cyclic GMP; Depression, Chemical; Double-Blind Method; Drugs, Chinese Herbal; Female; Glaucoma, Open-Angle; Humans; Intraocular Pressure; Male; Middle Aged; Miotics; Pilocarpine; Pupil; Rabbits