Anti-osteoporotic effects of alisol C 23-acetate via osteoclastogenesis inhibition.

Alismatis rhizoma (AR) is the dried rhizome of Alisma orientale (Sam.) Juz. (Alismataceae). This traditional Chinese formula is diuretic, hypoglycemic, and hypolipidemic. Alisol C 23-acetate (AC23A) from AR is anti-inflammatory and ameliorates certain metabolic diseases. However, the mechanism by which AC23A mitigates osteoporosis is unknown. The present study investigated the anti-osteoporotic effects of AC23A in vivo and in vitro. In an ovariectomized (OVX) rat model, AC23A ameliorated OVX-induced organ coefficients and trabecular bone loss. In OVX rats, AC23A treatment lowered serum TRAP5b, CTK, ß-CTX, TNF-α, IL-6, and IL-1ß, raised serum E2, and did not significantly change serum OCN or BALP. AC23A inhibited osteoclast formation in a rat co-culture system without affecting osteoblast activity. RANK (receptor activator of nuclear factor kappaB) signaling channels are vital osteoclastogenesis transcription elements. AC23A inhibited RANK ligand (RANKL)-induced TRAP, c-Fos, MMP9, NFATc1, and CTK expression and JNK phosphorylation. Therefore, AC23A is anti-osteoclastogenic in vitro and in vivo by inhibiting RANKL-induced osteoclast differentiation and function. Moreover, AC23A could help prevent or limit osteoclast-mediated bone diseases by inhibiting osteoclastogenesis.

The Effect of Dietary Vitamin K1 Supplementation on Trabecular Meshwork and Retina in a Chronic Ocular Hypertensive Rat Model.

Purpose: The pathophysiologic relationship between vitamin K and glaucoma remains largely unknown. The aim of the study was to explore the effect of dietary vitamin K supplementation in a rat glaucoma model. Methods: Rats were randomly divided into two groups: standard diet and high vitamin K1 (VitK1) diet (300 mg VitK1/kg diet). Induction of chronic ocular hypertension by episcleral vein cauterization was performed on the right eye. The left eye with sham operation served as controls. Rats received standard or high VitK1 diets for 5 weeks after surgery until the end of experiment. Immunohistochemistry analyses of the retina and trabecular meshwork were performed. The change in coagulation function and IOP were evaluated. Results: We observed a significant declined IOP at 2 weeks after surgery in the high VitK1 group compared with the control group. High VitK1 showed no significant effect on the body weight, rat phenotypes, or coagulation function. High VitK1 significantly inhibited the loss of retinal ganglion cells in the retina and increased the expression of matrix gla protein. High VitK1 also ameliorated the collapsed trabecular meshwork structure and increased collagen staining in the trabecular meshwork. Conclusions: High VitK1 intake inhibited the loss of retinal ganglion cells during glaucomatous injury, probably by increasing the expression of matrix gla protein. A transient decrease in the IOP was observed in the high VitK1 group, implying a potential effect of VitK1 on aqueous outflow. Retinal ganglion cells protection by high VitK1 supplementation may be due to the IOP-lowering effects as well as neuroprotective effect. Further research is required to delineate these processes.

Development of a Novel Intraocular-Pressure-Lowering Therapy Targeting ATX.

Elevated intraocular pressure (IOP) is the major cause of glaucoma, which is the second leading cause of blindness. However, current glaucoma treatments cannot completely regulate IOP and progression of glaucoma. Our group recently found that autotaxin (ATX) activity in human aqueous humor (AH) was positively correlated with increased IOP in various subtypes of glaucoma. To develop new IOP-lowering treatments, we generated a novel ATX inhibitor as an ophthalmic drug by high-throughput screening, followed by inhibitor optimization. Administration of the optimized ATX inhibitor (Aiprenon) reduced IOP in laser-treated mice exhibiting elevated IOP and higher level of ATX activity in AH and normal mice in vivo. The stimulation of ATX induced outflow resistance in the trabecular pathway; however, administration of Aiprenon recovered the outflow resistance in vitro. The in vitro experiments implied that the IOP-lowering effect of Aiprenon could be correlated with the altered cellular behavior of trabecular meshwork (TM) and Schlemm's canal endothelial (SC) cells. Overall, our findings showed that ATX had major impact in regulating IOP as a target molecule, and potent ATX inhibitors such as Aiprenon could be a promising therapeutic approach for lowering IOP.

Thermosensitive chitosan-gelatin-based hydrogel containing curcumin-loaded nanoparticles and latanoprost as a dual-drug delivery system for glaucoma treatment.

Elevated intraocular pressure (IOP) in glaucoma is due to impairment of aqueous humor drainage via the uveoscleral or trabecular outflow pathway. Latanoprost reduces IOP by increasing the uveoscleral outflow. Despite its potency, long-term daily application of it may cause undesirable side effects and many require more than one medication for IOP control. Recent studies have suggested that oxidative stress in the trabecular meshwork (TM) play an important role in the pathogenesis of impaired trabecular outflow facility. Curcumin, a natural phenolic compound, possesses anti-oxidant and anti-inflammation properties. In this study, we developed a thermosensitive hydrogel containing latanoprost and curcumin-loaded nanoparticles (CUR-NPs), and evaluated its possible therapeutic effects with cultured human TM cells under oxidative stress. The results demonstrated that 20 µM of CUR-NPs might be the optimal concentration to treat TM cells without causing cytotoxicity. Using the newly developed system, both latanoprost and CUR-NPs displayed a sustained-release profile. Treatment with this hydrogel containing CUR-NPs effectively decreased the oxidative stress-mediated damage in TM cells via decreasing inflammation-related gene expression, mitochondrial reactive oxygen stress (ROS) production and apoptosis level. The in vivo biocompatibility revealed no signs of inflammation or damage after topical application of developed hydrogel in rabbits. These results suggest that this dual-drug delivery system might enhance both trabecular and uveoscleral outflow and is promising to develop into a novel treatment for glaucoma.

Role of the water-drinking test in medically treated primary open angle glaucoma patients.

PURPOSE: The water-drinking test (WDT) has recently re-emerged as a possible way to determine the competency of the trabecular meshwork. We performed a prospective interventional study to test the hypothesis that the WDT could be useful in assessing fluctuations in patients undergoing treatment for primary open angle glaucoma (POAG). METHODS: We included 122 patients; 62 on medical treatment for POAG (n=123 eyes) and 60 controls (n=120 eyes). The study group had been on intraocular pressures (IOP) lowering treatment continuously for at least 3months with stable IOP. The WDT was performed during fasting and was considered positive if it fluctuated ≥6mmHg. RESULTS: The patients on medical treatment had a mean age of 50.56±18.45 years vs. 51.35±11.22 for the controls (P=0.34); with 71% being female in the study group and 77% in the control group. In the study group; 52% were on beta blockers (n=64), 27% combination of two or more medications (n=33), 19% prostaglandin analogues (n=24) and 2% alpha agonists (n=2). The WDT was positive in 17.07% (n=21) in the study group and 2.5% (n=3) in the control group (P=0.0001). The mean fluctuation was 7.14±2.15mmHg in the study group and 6.00±0mmHg in the controls (P=0.33). A positive WDT was found in 33.33% (n=11) of those on combination therapy; 12.5% (n=3) prostaglandin analogues and 10.94% (n=7) beta blockers (P=0.03). Combination therapy had the highest positive WDT fluctuation (7.54±2.87) followed by prostaglandin analogues (7.00±1.00) and beta blockers (6.57±0.78) with a P value of 0.44. CONCLUSIONS: The WDT can identify significant fluctuations in eyes with POAG that are medically treated.

Current therapeutic options and treatments in development for the management of primary open-angle glaucoma.

Primary open angle glaucoma (POAG) is the most common type of glaucoma, and is responsible for approximately 90% of glaucoma cases in North America. POAG is characterized by an asymptomatic onset, where patients do not present with symptoms until significant visual loss occurs in late stages of the disease. Importantly, while glaucoma is associated with several risk factors that contribute to damage and disease progression, intraocular pressure (IOP) is the only proven modifiable risk factor at this time. Treatments for POAG include use of pharmacologic and surgical interventions. As of this writing, available pharmacologic options reduce IOP through reduction of aqueous humor production or by facilitating aqueous humor drainage through the uveoscleral outflow pathway (the unconventional pathway). Although cholinergic agonists (eg, pilocarpine) indirectly targets aqueous humor draining through the trabecular meshwork/Schlemm's canal (the conventional outflow pathway), cholinergic agonists are not frequently used, and as of this writing, no agents are currently available that target both the conventional and unconventional outflow pathways. Therapies in late-stage development include trabodenoson, netardsudil, and latanoprostene bunod.

The protective effects of silibinin in the treatment of streptozotocin-induced diabetic osteoporosis in rats.

Diabetic osteoporosis (DO) is a complication of diabetes mellitus. Our previous study showed that silibinin can attenuate high glucose mediated human bone marrow stem cells dysfunction through antioxidant effect. However, no study has yet investigated the effect of silibinin in diabetic rats. Therefore, we assessed the effects of silibinin on bone characteristics in streptozotocin-induced diabetic rats. The aim of our study was to determine whether providing silibinin in the different supplementation could prevent bone loss in diabetic rats or not. Rats were randomly divided into four groups: (1) control group (CG) (n=10); (2) diabetic group (DG) (n=10); (3) diabetic group with 50mgkg-1day-1 of silibinin orally (DG-50) (n=10); and (4) diabetic group with 100mgkg-1day-1 of silibinin orally (DG-100) (n=10). 12 weeks after streptozotocin (STZ) injection, the femora from all rats were assessed and oxidative stress was evaluated. Bone mineral density was significantly decreased in diabetic rats; these effects were prevented by treatment with silibinin (100mgkg-1day-1 orally). Similarly, in the DG and DG-50 groups, changes in microarchitecture of femoral metaphysis assessed by microcomputed tomography demonstrated simultaneous existence of diabetic osteoporosis; these impairments were prevented by silibinin (100mgkg-1day-1 orally). In conclusion, silibinin supplementation may have potential use as a possible therapy for maintaining skeletal health and these results can enhance the understanding of diabetic osteoporosis induced by diabetes.

Discovery of the ROCK inhibitor netarsudil for the treatment of open-angle glaucoma.

Inhibition of Rho kinase (ROCK) to improve fluid outflow through the trabecular meshwork and lower intraocular pressure is a strategy for the development of new anti-glaucoma agents. Alpha-aryl-beta-amino isoquinoline analogs were identified as potent ROCK inhibitors. Compounds that provided a longer duration of intraocular pressure reduction in Dutch Belted rabbits also inhibited norepinephrine transporter. Ester 60 improved bioavailability of its parent ROCK inhibitor, 29 (Ki=0.2nM) and demonstrated an effective and sustained IOP reduction for 24h after dosing. From these studies, netarsudil (a.k.a. AR-13324) was discovered and is currently in clinical trials for the treatment of glaucoma and ocular hypertension.

Tetramethylpyrazine (TMP), an Active Ingredient of Chinese Herb Medicine Chuanxiong, Attenuates the Degeneration of Trabecular Meshwork through SDF-1/CXCR4 Axis.

BACKGROUND: A traditional Chinese medicine, Tetramethylpyrazine (TMP), has been prescribed as a complementary treatment for glaucoma to improve patient prognosis. However, the pharmacological mechanism of action of TMP is poorly understood. In previous studies, we demonstrated that TMP exerts potent inhibitory effects on neovascularization, suppresses the tumorigenic behavior of glioma cells, and protects neural cells by regulating CXCR4 expression. Here, we further investigated whether the SDF-1/CXCR4 pathway is also involved in the TMP-mediated activity in trabecular meshwork cells. METHODOLOGY/PRINCIPAL FINDINGS: CXCR4 expression was examined by quantitative real-time PCR in trabecular and iris specimens from 54 primary open-angle glaucoma (POAG) patients who required surgery and 19 non-glaucomatous donors. Our data revealed markedly elevated CXCR4 expression in the trabecular meshwork of POAG patients compared with that of controls. Consistently, CXCR4 expression was much higher in glaucomatous trabecular meshwork cells than in normal trabecular meshwork cells. Using RT-PCR and western blot assays, we determined that glaucoma-related cytokines and dexamethasone (DEX) also significantly up-regulated CXCR4 expression in primary human trabecular meshwork (PHTM) cells. Moreover, the TGF-ß1-mediated induction of CXCR4 expression in PHTM cells was markedly down-regulated by TMP compared with control treatment (PBS) and the CXCR4 antagonist AMD3100. In addition, TMP could counteract the TGF-ß1-induced effects on stress fiber accumulation and expansion of PHTM cells. TMP markedly suppressed the migration of PHTM cells stimulated by TGF-ß1 in transwell and scratch wound assays. TMP also suppressed the extracellular matrix (ECM) accumulation induced by TGF-ß2. CONCLUSIONS: Our findings demonstrate that CXCR4 might be involved in the pathogenetic changes in the trabecular meshwork of patients with POAG. Additionally, TMP might exert its beneficial effects in POAG patients by down-regulating CXCR4 expression.

Preclinical pharmacology, ocular tolerability and ocular hypotensive efficacy of a novel non-peptide bradykinin mimetic small molecule.

We sought to characterize the ocular pharmacology, tolerability and intraocular pressure (IOP)-lowering efficacy of FR-190997, a non-peptidic bradykinin (BK) B2-receptor agonist. FR-190997 possessed a relatively high receptor binding affinity (Ki = 27 nM) and a high in vitro potency (EC50 = 18.3 ± 4.4 nM) for inositol-1-phosphate generation via human cloned B2-receptors expressed in host cells with mimimal activity at B1-receptors. It also mobilized intracellular Ca2+ in isolated human trabecular meshwork (h-TM), ciliary muscle (h-CM), and in immortalized non-pigmented ciliary epithelial (h-iNPE) cells (EC50s = 167-384 nM; Emax = 32-86% of BK-induced response). HOE-140, a selective B2-receptor antagonist, potently blocked the latter effects of FR-190997 (e.g., IC50 = 7.3 ± 0.6 nM in h-CM cells). FR-190997 also stimulated the release of prostaglandins (PGs) from h-TM and h-CM cells (EC50s = 60-84 nM; Emax = 29-44% relative to max. BK-induced effects). FR-190997 (0.3-300 µg t.o.) did not activate cat corneal polymodal nociceptors and did not cause ocular discomfort in Dutch-Belted rabbits, but it was not well tolerated in New Zealand albino rabbits and Hartley guinea pigs. A single topical ocular (t.o.) dose of 1% FR-190997 in Dutch-Belted rabbits and mixed breed cats did not lower IOP. However, FR-190997 efficaciously lowered IOP of conscious ocular hypertensive cynomolgus monkey eyes (e.g., 34.5 ± 7.5% decrease; 6 h post-dose of 30 µg t.o.; n = 8). Thus, FR-190997 is an unexampled efficacious ocular hypotensive B2-receptor non-peptide BK agonist that activates multiple signaling pathways to cause IOP reduction.

Ascorbic acid modulation of iron homeostasis and lysosomal function in trabecular meshwork cells.

PURPOSE: To investigate the antioxidant properties and biological functions of ascorbic acid (AA) on trabecular meshwork (TM) cells. METHODS: Primary cultures of porcine TM cells were supplemented for 10 days with increasing concentrations of AA. Antioxidant properties against cytotoxic effect of H2O2 were evaluated by monitoring cell viability. Redox-active iron was quantified using calcein-AM. Intracellular reactive oxygen species (iROS) production was quantified using H2DCFDA. Ferritin and cathepsin protein levels were analyzed by Western blot. Autophagy was evaluated by monitoring lipidation of LC3-I to LC3-II. Lysosomal proteolysis and cathepsins activities were quantified using specific fluorogenic substrates. RESULTS: AA exerts a dual effect against oxidative stress in TM cells, acting as an anti-oxidant or a pro-oxidant, depending on the concentration used. The pro-oxidant effect of AA was mediated by free intracellular iron and correlated with increased protein levels of ferritin and elevated iROS. In contrast, antioxidant properties correlated with lower ferritin and basal iROS content. Ascorbic acid supplementation also caused induction of autophagy, as well as increased lysosomal proteolysis, with the latter resulting from higher proteolytic activation of lysosomal cathepsins in treated cultures. CONCLUSIONS: Our results suggest that the reported decrease of AA levels in plasma and aqueous humor can compromise lysosomal degradation in the outflow pathway cells with aging and contribute to the pathogenesis of glaucoma. Restoration of physiological levels of vitamin C inside the cells might improve their ability to degrade proteins within the lysosomal compartment and recover tissue function.

Pharmacological regulation of SPARC by lovastatin in human trabecular meshwork cells.

PURPOSE: Statins have been shown to increase aqueous outflow facility. The matricellular protein SPARC (secreted protein acidic and rich in cysteine) is a critical mediator of aqueous outflow and intraocular pressure (IOP). Here, we examine the effects of lovastatin on SPARC expression in trabecular meshwork (TM) cells, exploring the molecular mechanisms involved. METHODS: Primary cultured human TM cells were incubated for 24, 48, and 72 hours with 10 µM lovastatin. In separate cultures, media was supplemented with either farnesyl pyrophosphate (FPP) or geranylgeranyl pyrophosphate (GGPP) for the duration of the 72-hour time point experiment. Trabecular meshwork cells were also pretreated for 24 hours with lovastatin followed by 24-hour stimulation with 3 ng/mL TGF-ß2. Cell lysates and media were harvested and relative mRNA and protein level changes were determined. Krüppel-like factor 4 (KLF4) localization in normal human anterior segments was examined by immunofluorescence. Adenovirus expressing human KLF4 was used and relative changes in SPARC mRNA and protein levels were assessed. RESULTS: Incubating TM cells with lovastatin suppressed SPARC mRNA and protein levels. This effect was reversed upon media supplementation with GGPP but not FPP. Pretreating cells with lovastatin inhibited TGF-ß2 induction of SPARC. The KLF4 transcription factor was expressed throughout the TM and the inner and outer walls of Schlemm's canal. Lovastatin treatment upregulated KLF4 mRNA and protein levels. Overexpression of KLF4 downregulated SPARC expression. CONCLUSIONS: Collectively, our data identify lovastatin as an important pharmacological suppressor of SPARC expression in TM cells, and provide further insight into the molecular mechanisms mediating statin enhancement of aqueous outflow facility.

Mitomycin C versus 5-fluorouracil as an adjunctive treatment for trabeculectomy: a meta-analysis of randomized clinical trials.

Mitomycin C (MMC) and 5-fluorouracil (5-FU) are the most frequently utilized adjuvant therapies in trabeculectomy (TRAB), but there is no general consensus as to the direct comparative efficacy and safety of these two adjuvants. In this study, the authors conducted a meta-analysis to compare the efficacy and safety of augmenting TRAB with MMC or 5-FU. A systematic review with meta-analysis was conducted and five randomized controlled clinical trials comparing MMC versus 5-FU as adjunctive therapies were identified, totaling 416 participants. A lower pooled mean IOP and higher complete and qualified success rates were observed in the MMC arm than in the 5-FU arm. Epithelial corneal defects were the unique complication reported more frequently with 5-FU compared to MMC treatment. Compared to TRAB with 5-FU, TRAB with MMC was associated with higher rates of complete and qualified surgical success and was not associated with increased incidences of postoperative complications.

[Multikinase inhibitors as a new approach in neovascular age-related macular degeneration (AMD) treatment: in vitro safety evaluations of axitinib, pazopanib and sorafenib for intraocular use]. / Multikinase-inhibitoren als therapeutischer ansatz bei neovaskulärer AMD: in-vitro-evaluation der sicherheit von axitinib, pazopanib und sorafenib zur intraokularen anwendung.

BACKGROUND: Multikinase inhibitors (MKI) interfere effectively at different levels of the neovascularisation cascade. Early clinical and experimental data suggest that MKIs represent a promising novel approach for the treatment of neovascular age-related macular degeneration (AMD). However, so far little is known about the biocompatibility of MKIs regarding human ocular cells. This in vitro study investigates and compares the biocompatibility of three MKIs, axitinib, pazopanib, and sorafenib regarding ocular cells of the anterior and posterior segments, as well as organ-cultured donor corneas. METHODS: Primary human optic nerve head astrocytes (ONHA), trabecular meshwork cells (TMC), and retinal pigment epithelium (RPE), human corneal endothelial and lens epithelial cells (CEC and LEC) were treated with different concentrations of axitinib, pazopanib, or sorafenib (0.1 to 100 µg/mL). To simulate oxidative stress, the cells were additionally co-incubated with 400 µM hydrogen peroxide. Induction of cell death and cellular viability were examined by live-dead assay and tetrazolium dye reduction assay (MTT). In addition, the influence of the three substances on human corneal endothelium was evaluated in seropositive donor corneas in organ culture by phase contrast microscopy. RESULTS: Up to a concentration of 7.5 mg/mL of the substances tested in any cell type examined, no toxic effects were found. Even after 10 days of incubation of organ-cultured donor corneas with 7.5 µg/mL, axitinib, pazopanib, or sorafenib, no evidence for endothelial toxicity was found. CONCLUSION: All three MKIs tested, axitinib, pazopanib, and sorafenib showed a good biocompatibility on the investigated ocular cells. Even under conditions of oxidative stress, there were no toxic effects up to a concentration of 7.5 µg/mL. Only at higher concentrations, there was a dose-dependent decrease in cellular viability and pronounced induction of cell death. These effects on cellular viability and induction of cell death appeared to be stronger with pazopanib, followed by sorafenib, than with axitinib.

Preventive effects of omega-3 and omega-6 Fatty acids on peroxide mediated oxidative stress responses in primary human trabecular meshwork cells.

Pathologic processes in glaucoma include increased apoptosis, accumulation of extracellular material in the trabecular meshwork and optic nerve, condensations of the cytoskeleton and precocious cellular senescence. Oxidative stress was shown to generate these alterations in primary ocular cells. Fatty acids omega-3 and -6 are alleged to constitute a prophylaxis against these deleterious effects. Here, we tested actual preventive effects omega-3 and -6 against peroxide induced stress responses in primary human trabecular meshwork cells. Changes of mitochondrial activity, proliferation, heat shock proteins, extracellular matrix components, and inflammatory markers were evaluated. Alterations of the cytoskeleton were evaluated by phalloidin labeling. Here we report a repressive effect of omega-6 on metabolic activity and proliferation, which was not detected for omega-3. Both agents were able to prevent the anti-proliferative effect of H2O2, but only omega-3 prevented metabolic repression. Expression of heat shock protein 27 was unaltered by both fatty acids, whereas heat shock protein 90 was significantly induced by both. Omega-6 increased fibronectin and connective tissue growth factor synthesis, as well as the amount of secreted fibronectin. Omega-3, instead, induced plasminogen activator inhibitor 1 synthesis. H2O2 further increased fibronectin production in omega-6 supplemented cells, which was not the case in omega-3 treated cells. H2O2 stimulation of plasminogen activator inhibitor 1 and connective tissue growth factor was repressed by both fatty acids. Both fatty acids appeared to abolish H2O2 mediated stimulation of nuclear factor κB and IL-6, but not IL-1α and IL-8. H2O2 induced formation of cross-linked actin networks and stress fibers, which was reduced by preemptive application of omega-3. Omega-6, in contrast, had no protective effect on that, and even seemed to promote condensation. Based on the observed side effects of omega-6, omega-3 appears to be the more beneficial fatty acid in respect of prophylactic intake for prevention of a glaucomatous disease.

Intracameral voriconazole: in vitro safety for human ocular cells.

Fungal keratitis is a sight-threatening infection of the cornea. It sometimes leads to loss of the eye. Despite an expanding range of fungal pathogens, there are only few therapeutic agents for its treatment available. Voriconazole is a second-generation synthetic triazole with a broad action against yeasts and molds. The current study investigates the safety of voriconazole for intracameral application in a cell culture model. Endothelial toxicity of voriconazole was evaluated in cultured human corneas. Possible toxic effects of voriconazole (10 microg /mL-10mg/mL) in corneal endothelial cells (CEC), primary human trabecular meshwork cells (TMC), and primary human retinal pigment epithelium (RPE) cells were evaluated after 24h and under conditions of inflammatory stress by treatment with tumor-necrosis-factor alpha (TNF-alpha), lipopolysaccharides (LPS), or interleukin-6 (IL-6) and hydrogen peroxide. Toxicity was evaluated by tetrazolium dye-reduction assay, and cell viability was quantified by a microscopic live-dead assay. No corneal endothelial toxicity could be detected after 30 days of treatment with 250 microg /mL of voriconazole. Concentrations up to 1mg/mL had no influence on CEC, TMC, or RPE cell proliferation, or on cell viability when administered for 24h. Hydrogen peroxide exposure did not increase cellular toxicity of voriconazole at concentrations from 10 to 250 microg /mL. After preincubation with TNF-alpha, LPS, or IL-6 for 24h and subsequent voriconazole treatment for 24h, no significant decrease in proliferation or viability was observed. This study showed no significant toxicity for voriconazole on CEC, TMC, RPE cells, or human corneal endothelium when administered in therapeutic concentrations up to 250 microg /mL.

Relationship between glaucoma and selenium levels in plasma and aqueous humour.

AIM: The aim of the study was to compare selenium levels in plasma and aqueous humour in subjects with and without primary open-angle glaucoma (POAG). METHODS: Forty-seven POAG cases and 54 controls in this case-control study were recruited from surgery patients at the University Physician's Ophthalmology Clinic in Tucson, Arizona, USA. Aqueous humour and plasma selenium were determined by high-performance liquid chromatography ion channel plasma mass spectrometry (HPLC ICP-MS). Potential confounders were assessed via a questionnaire. Biological samples were collected and processed at surgery and analysed for selenium content after collection was complete. Outcome measures included the odds of glaucoma in relationship to plasma selenium, aqueous humour selenium, and the ratio of levels of aqueous humour selenium to plasma selenium. RESULTS: Tertile of selenium and its relationship to POAG was examined. After adjustment for common glaucoma risk factors, the odds of glaucoma in the highest tertile of plasma selenium (OR = 11.3; p = 0.03) and the middle tertile of aqueous humour selenium (OR = 0.06; p = 0.02) was significantly associated with glaucoma. CONCLUSION: Although a causal pathway cannot be inferred from our analysis, our data, added to that of others, suggest that the pathology is selenium-related.

Effect of topical Ginkgo biloba extract on steroid-induced changes in the trabecular meshwork and intraocular pressure.

OBJECTIVE: To study the effects of Ginkgo biloba extract (GBE) on dexamethasone (DEX)-induced ocular hypertension. METHODS: Rabbits aged 7 weeks received topical TobraDEX (Alcon Labs, Hünenberg, Switzerland) and/or 5 microg of GBE four times daily for 14 days. Intraocular pressure (IOP) was recorded every 3 days. After enucleation, trabecular meshwork (TM) cellularity and extracellular matrix deposition were graded. The effect of GBE on apoptosis and expression of myocilin and cell stress-related genes in DEX-treated human TM cells were studied by immunofluorescence, Western blotting, and quantitative polymerase chain reaction. RESULTS: Ginkgo biloba extract suppressed DEX-induced IOP elevation in rabbits. It reduced the DEX-associated accumulation of extracellular materials within the cribriform layers of the TM and achieved better TM cellularity. In cultured human TM cells, GBE substantially attenuated anti-Fas ligand-induced apoptosis and reduced DEX-induced myocilin expression. Ginkgo biloba extract modulated the expression of alphaB-crystallin and heat-shock proteins 70 and 90alpha but not other stress-related genes. Furthermore, changes associated with DEX were found less in GBE-treated or GBE-primed TM cells. CONCLUSION: We showed that GBE, a nontoxic, antiapoptotic, herbal compound significantly suppressed steroid-induced IOP elevation in rabbits and it seems to prevent the adverse effects of DEX on TM cells. CLINICAL RELEVANCE: Ginkgo biloba extract could be a therapeutic agent or dietary supplement to prevent steroid-induced ocular hypertension.

Electron probe X-ray microanalysis of intact pathway for human aqueous humor outflow.

Intraocular pressure (IOP) is regulated by the resistance to outflow of the eye's aqueous humor. Elevated resistance raises IOP and can cause glaucoma. Despite the importance of outflow resistance, its site and regulation are unclear. The small size, complex geometry, and relative inaccessibility of the outflow pathway have limited study to whole animal, whole eye, or anterior-segment preparations, or isolated cells. We now report measuring elemental contents of the heterogeneous cell types within the intact human trabecular outflow pathway using electron-probe X-ray microanalysis. Baseline contents of Na(+), K(+), Cl(-), and P and volume (monitored as Na+K contents) were comparable to those of epithelial cells previously studied. Elemental contents and volume were altered by ouabain to block Na(+)-K(+)-activated ATPase and by hypotonicity to trigger a regulatory volume decrease (RVD). Previous results with isolated trabecular meshwork (TM) cells had disagreed whether TM cells express an RVD. In the intact tissue, we found that all cells, including TM cells, displayed a regulatory solute release consistent with an RVD. Selective agonists of A(1) and A(2) adenosine receptors (ARs), which exert opposite effects on IOP, produced similar effects on juxtacanalicular (JCT) cells, previously inaccessible to functional study, but not on Schlemm's canal cells that adjoin the JCT. The results obtained with hypotonicity and AR agonists indicate the potential of this approach to dissect physiological mechanisms in an area that is extremely difficult to study functionally and demonstrate the utility of electron microprobe analysis in studying the cellular physiology of the human trabecular outflow pathway in situ.