cyclic-gmp and Ocular-Hypertension

Glaucoma is a neurodegenerative disease of the eye with an estimated prevalence of more than 111.8 million patients worldwide by 2040, with at least 6 to 8 million projected to become bilaterally blind. Clinically, the current method of slowing glaucomatous vision loss is to reduce intraocular pressure (IOP). In this manuscript, we describe the in vitro cytoprotective and in vivo long lasting IOP-lowering activity of the poly D, L-lactic-co-glycolic acid (PLGA) nanoparticle-encapsulated hybrid compound SA-2, possessing nitric oxide (NO) donating and superoxide radical scavenging functionalities.. Hybrid compound SA-2 upregulated cGMP in hTM cells, increased outflow facility and decreased IOP in rodent models of OHT. Compound SA-2 possessing an antioxidant moiety provided additive cytoprotective activity to oxidatively stressed hTM cells by scavenging reactive oxygen species (ROS) and increasing SOD enzyme activity. Additionally, the PLGA nanosuspension formulation (SA-2 NPs) provided longer duration of IOP-lowering activity (up to 3 days) in comparison with the free non-encapsulated SA-2 drug. The data have implications for developing novel, non-prostaglandin therapeutics for IOP-lowering and cytoprotective effects with the possibility of an eye drop dosing regimen of once every 3 days for patients with glaucoma.

Topics: Administration, Ophthalmic; Adult; Aged, 80 and over; Animals; Antihypertensive Agents; Aqueous Humor; Biological Availability; Cells, Cultured; Cyclic GMP; Disease Models, Animal; Drug Carriers; Female; Free Radical Scavengers; Glycolates; Humans; Intraocular Pressure; Male; Mice, Inbred C57BL; Nitric Oxide Donors; Ocular Hypertension; Ophthalmic Solutions; Piperidines; Rats; Rats, Inbred BN; Rats, Sprague-Dawley; Reactive Oxygen Species; Sclera; Superoxide Dismutase; Tissue Distribution; Trabecular Meshwork; Venous Pressure

NCX 667, a novel nitric oxide (NO) donor with an isomannide core, was characterized for its IOP-lowering ability in animal models of ocular hypertension and glaucoma. Bioengineered human trabecular meshwork/Schlemm's canal (HTM/HSC) constructs were used to explore the mode of action.. Ocular normotensive New Zealand white (NZW) rabbits (ONT-rabbits), spontaneously ocular hypertensive pigmented Dutch-belted rabbits (sOHT-rabbits), hypertonic saline (5%)-induced transient ocular hypertensive NZW rabbits (tOHT-rabbits), ocular normotensive Beagle dogs (ONT-dogs), and laser-induced ocular hypertensive cynomolgus monkeys (OHT-monkeys) were used. NCX 667 or vehicle (30 µL) was instilled in a crossover, masked fashion and intraocular pressure (IOP) measured before dosing (baseline) and for several hours thereafter. The ONT-rabbits were used for cyclic guanosine monophosphate (cGMP) determination in ocular tissues after ocular dosing with NCX 667. Transforming growth factor-beta2 (TGFβ2) (2.5 ng/mL, six days)-treated HTM/HSC constructs were used to address changes in outflow facility.. NCX 667 resulted in robust and dose-dependent IOP decrease in all models used. Maximal IOP-lowering efficacy at 1% was -4.1 ± 0.6, -12.2 ± 2.7, -10.5 ± 2.0, -5.3 ± 0.8, and -6.6 ± 1.9 mmHg, respectively, in ONT-dogs, sOHT-rabbits, tOHT-rabbits, ONT-rabbits, and OHT-monkeys. In ONT-rabbits NCX 667 (1%) increased cGMP in aqueous humor (AH) but not in retina and iris/ciliary body. NCX 667 concentration-dependently increased outflow facility in TGFβ2-treated HTM/HSC constructs (outflow facility, 0.10 ± 0.06 and 0.30 ± 0.10 µL/min/mmHg/mm2, respectively, in vehicle- and NCX 667-treated constructs).. NCX 667 leads to robust IOP lowering in several animal models. Evidence in HTM/HSC constructs indicate that the IOP reduction likely results from NO-mediated increase of the conventional outflow pathway. Other mechanisms including changes in AH production and episcleral vein pressure may not be excluded at this time.

Topics: Animals; Aqueous Humor; Bridged Bicyclo Compounds, Heterocyclic; Cyclic GMP; Disease Models, Animal; Dogs; Female; Intraocular Pressure; Limbus Corneae; Macaca fascicularis; Nitric Oxide Donors; Ocular Hypertension; Rabbits; Trabecular Meshwork; Transforming Growth Factor beta2

The aim of the study was to investigate the ocular hypotensive activity of a nitric oxide (NO)-donating latanoprost, BOL-303259-X, following topical administration. The effect of BOL-303259-X (also known as NCX 116 and PF-3187207) on intraocular pressure (IOP) was investigated in monkeys with laser-induced ocular hypertension, dogs with naturally-occurring glaucoma and rabbits with saline-induced ocular hypertension. Latanoprost was used as reference drug. NO, downstream effector cGMP, and latanoprost acid were determined in ocular tissues following BOL-303259-X administration as an index of prostaglandin and NO-mediated activities. In primates, a maximum decrease in IOP of 31% and 35% relative to baseline was achieved with BOL-303259-X at doses of 0.036% (9 μg) and 0.12% (36 μg), respectively. In comparison, latanoprost elicited a greater response than vehicle only at 0.1% (30 μg) with a peak effect of 26%. In glaucomatous dogs, IOP decreased from baseline by 44% and 10% following BOL-303259-X (0.036%) and vehicle, respectively. Latanoprost (0.030%) lowered IOP by 27% and vehicle by 9%. Intravitreal injection of hypertonic saline in rabbits increased IOP transiently. Latanoprost did not modulate this response, whereas BOL-303259-X (0.036%) significantly blunted the hypertensive phase. Following BOL-303259-X treatment, latanoprost acid was significantly elevated in rabbit and primate cornea, iris/ciliary body and aqueous humor as was cGMP in aqueous humor. BOL-303259-X lowered IOP more effectively than latanoprost presumably as a consequence of a contribution by NO in addition to its prostaglandin activity. The compound is now in clinical development for the treatment of glaucoma and ocular hypertension.

Topics: Administration, Topical; Animals; Antihypertensive Agents; Aqueous Humor; Cell Line; Ciliary Body; Cyclic GMP; Dinoprost; Disease Models, Animal; Dogs; Drug Evaluation, Preclinical; Female; Glaucoma; Guanylate Cyclase; Intraocular Pressure; Iris; Latanoprost; Macaca fascicularis; Male; Nitric Oxide; Nitric Oxide Donors; Ocular Hypertension; Prostaglandins F, Synthetic; Rabbits; Rats; Tonometry, Ocular

Nitric oxide (NO) is involved in a variety of physiological processes including ocular aqueous humor dynamics by targeting mechanisms that are complementary to those of prostaglandins. Here, we have characterized a newly synthesized compound, NCX 125, comprising latanoprost acid and NO-donating moieties.. NCX 125 was synthesized and tested in vitro for its ability to release functionally active NO and then compared with core latanoprost for its intraocular pressure (IOP)-lowering effects in rabbit, dog, and nonhuman primate models of glaucoma.. NCX 125 elicited cGMP formation (EC(50) = 3.8 + or - 1.0 microM) in PC12 cells and exerted NO-dependent iNOS inhibition (IC(50) = 55 + or - 11 microM) in RAW 264.7 macrophages. NCX 125 lowered IOP to a greater extent compared with equimolar latanoprost in: (a) rabbit model of transient ocular hypertension (0.030% latanoprost, not effective; 0.039% NCX 125, Delta(max) = -10.6 + or - 2.3 mm Hg), (b) ocular hypertensive glaucomatous dogs (0.030% latanoprost, Delta(max)= -6.7 + or - 1.2 mm Hg; 0.039% NCX 125, Delta(max) = -9.1 + or - 3.1 mm Hg), and (c) laser-induced ocular hypertensive non-human primates (0.10% latanoprost, Delta(max) = -11.9 + or - 3.7 mm Hg, 0.13% NCX 125, Delta(max) = -16.7 + or - 2.2 mm Hg). In pharmacokinetic studies, NCX 125 and latanoprost resulted in similar latanoprost-free acid exposure in anterior segment ocular tissues.. NCX 125, a compound targeting 2 different mechanisms, is endowed with potent ocular hypotensive effects. This may lead to potential new perspectives in the treatment of patients at risk of glaucoma.

Topics: Animals; Antihypertensive Agents; Aqueous Humor; Ciliary Body; Cyclic GMP; Disease Models, Animal; Dogs; Female; Glaucoma; Intraocular Pressure; Iris; Macaca fascicularis; Macrophages; Male; Nitric Oxide; Nitric Oxide Synthase Type II; Ocular Hypertension; Ophthalmic Solutions; Prostaglandins F, Synthetic; Prostaglandins, Synthetic; Rabbits; Tumor Cells, Cultured

Understanding the mechanisms of neuronal cell death in glaucoma is important for devising new treatments. Excitatory amino acids, excessive Ca(2+) influx, and formation of nitric oxide (NO) via NO synthase (NOS)-1 could be involved in glaucomatous neuropathy. The purpose of the present study was to examine the retinal nitridergic pathway activity in rats exposed to experimentally elevated intraocular pressure.. Weekly injections of HA were performed unilaterally in the rat anterior chamber, whereas the contralateral eye was injected with saline solution. At 3 or 6 weeks of treatment, retinal NOS activity was assessed through the conversion of (3)H-L-arginine to (3)H-L-citrulline, whereas NOS-1, -2, and -3 levels were assessed by Western blotting. L-Arginine uptake was measured using (3)H-l-arginine, whereas mRNA levels of L-arginine transporters were determined by semiquantitative RT-PCR. In addition, cyclic guanosine monophosphate (cGMP) levels were quantified by radioimmunoassay.. At both 3 and 6 weeks of treatment, NOS activity significantly increased in HA-injected eyes although no changes in retinal NOS-1, -2, or -3 levels were observed in eyes injected with HA. L-Arginine influx and mRNA levels of cationic amino acid transporter type (CAT)-1 and -2 significantly increased in retinas from hypertensive eyes. Retinal cGMP levels significantly increased in eyes injected with HA for 3 but not 6 weeks.. These results suggest a significant activation of the retinal nitridergic pathway in hypertensive eyes.

Topics: Amino Acid Transport Systems, Basic; Animals; Anterior Chamber; Arginine; Blotting, Western; Citrulline; Cyclic GMP; Disease Models, Animal; Hyaluronic Acid; Intraocular Pressure; Male; Nitric Oxide; Nitric Oxide Synthase; Nitric Oxide Synthase Type I; Nitric Oxide Synthase Type II; Nitric Oxide Synthase Type III; Ocular Hypertension; Radioimmunoassay; Rats; Rats, Wistar; Retina; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger

To study the relationship between the levels of cyclic adenosine monophosphate (cAMP), cyclic guanosine monophos-phate (cGMP) in the plasma, iris and aqueous humor and high intraocular pressure in rabbits.. The quantitative tests of cAMP and cGMP from rabbits were carried out by radioimmunoassay technique.. The results showed that there were 72.81 +/- 7.67, 141.08 +/- 16.70 and 28.40 +/- 0.49 of cAMP (nmol/L), and there were 10.37 +/- 6.15, 35.64 +/- 7.02 and 12.90 +/- 0.61 of cGMP (nmol/L) in the plasma, iris and aqueous humor respectively. The levels of cAMP were higher than those in the same samples from the animals as controls (P < 0.01), while the levels of cGMP were less than controls (P < 0.01).. High intraocular pressure may be significantly associated with the levels of cAMP and cGMP.

Topics: Animals; Aqueous Humor; Cyclic AMP; Cyclic GMP; Female; Iris; Male; Ocular Hypertension; Rabbits

To determine whether a new cyclic GMP analog, 2'-O-(4-benzoyl)benzoylguanosine 3',5' cyclic monophosphate (BB-cGMP), significantly reduces intraocular pressure in either normotensive or hypertensive eyes of rabbits.. Intraocular pressure of normal adult rabbits and/or rabbits with alpha-chymotrypsin-induced ocular hypertension was measured after topical application of BB-cGMP for up to 72 hours after treatment.. Data indicate that topical application of solutions containing BB-cGMP can significantly reduce intraocular pressure in normotensive eyes and, to a greater extent, hypertensive eyes for periods up to 12 hours for a single dose.. BB-cGMP holds interest both as a clinical agent in the management of intraocular pressure and for in vitro biochemical studies on the regulation of intraocular pressure.

Topics: Administration, Topical; Animals; Chymotrypsin; Cyclic GMP; Intraocular Pressure; Ocular Hypertension; Ophthalmic Solutions; Phosphodiesterase Inhibitors; Rabbits; Tonometry, Ocular