INJECTION FREQUENCY OF AFLIBERCEPT VERSUS RANIBIZUMAB IN A TREAT-AND-EXTEND REGIMEN FOR CENTRAL RETINAL VEIN OCCLUSION: A Randomized Clinical Trial.

PURPOSE: To prospectively investigate the injection frequency of aflibercept and ranibizumab in the treatment of macular edema in central retinal vein occlusion. METHODS: Patients with treatment-naive central retinal vein occlusion and macular edema were randomized to receive intravitreal injections with aflibercept (n = 22) or ranibizumab (n = 23) in a treat-and-extend regimen with a follow-up time of 18 months. After 3 loading doses, the treatment intervals were extended by 2 weeks to a maximum of 12 weeks. Intervals were shortened by 2 weeks if macular edema recurred. RESULTS: The number of injections was significantly lower in the aflibercept group with a mean of 10.9 injections (95% confidence interval, 9.6-12.3) compared with 14.4 in the ranibizumab group (95% confidence interval 12.7-16.1) at study completion (P = 0.0017). The mean treatment interval was significantly longer in the aflibercept group compared with the ranibizumab group 10.0 (95% confidence interval, 8.7-11.3) and 6.6 (95% confidence interval, 5.2-8.0) weeks, respectively (P < 0.001). No significant difference between the groups regarding visual acuity or central retinal thickness was observed. CONCLUSION: Patients with macular edema secondary to central retinal vein occlusion required significantly fewer intravitreal injections of aflibercept compared with ranibizumab when treated with a treat-and-extend regimen. This may reduce the treatment burden and, to some extent, the need for close monitoring of patients.

Regulation of trabecular meshwork cell contraction and intraocular pressure by miR-200c.

Lowering intraocular pressure (IOP) delays or prevents the loss of vision in primary open-angle glaucoma (POAG) patients with high IOP and in those with normal tension glaucoma showing progression. Abundant evidence demonstrates that inhibition of contractile machinery of the trabecular meshwork cells is an effective method to lower IOP. However, the mechanisms involved in the regulation of trabecular contraction are not well understood. Although microRNAs have been shown to play important roles in the regulation of multiple cellular functions, little is known about their potential involvement in the regulation of IOP. Here, we showed that miR-200c is a direct postranscriptional inhibitor of genes relevant to the physiologic regulation of TM cell contraction including the validated targets Zinc finger E-box binding homeobox 1 and 2 (ZEB1 and ZEB2), and formin homology 2 domain containing 1 (FHOD1), as well as three novel targets: lysophosphatidic acid receptor 1 (LPAR1/EDG2), endothelin A receptor (ETAR), and RhoA kinase (RHOA). Consistently, transfection of TM cells with miR-200c resulted in strong inhibition of contraction in collagen populated gels as well as decreased cell traction forces exerted by individual TM cells. Finally, delivery of miR-200c to the anterior chamber of living rat eyes resulted in a significant decrease in IOP, while inhibition of miR-200c using an adenoviral vector expressing a molecular sponge led to a significant increase in IOP. These results demonstrate for the first time the ability of a miRNA to regulate trabecular contraction and modulate IOP in vivo, making miR-200c a worthy candidate for exploring ways to alter trabecular contractility with therapeutic purposes in glaucoma.

Endogenous production of extracellular adenosine by trabecular meshwork cells: potential role in outflow regulation.

PURPOSE: To investigate the mechanisms for endogenous production of extracellular adenosine in trabecular meshwork (TM) cells and evaluate its physiological relevance to the regulation of aqueous humor outflow facility. METHODS: Extra-cellular levels of adenosine monophosphate (AMP) and adenosine in porcine trabecular meshwork (PTM) cells treated with adenosine triphosphate (ATP), AMP, cAMP or forskolin with or without specific inhibitors of phosphodiesterases (IBMX) and CD73 (AMPCP) were determined by high-pressure liquid chromatography fluorometry. Extracellular adenosine was also evaluated in cell cultures subjected to cyclic mechanical stress (CMS) (20% stretching; 1 Hz) and after disruption of lipid rafts with methyl-ß-cyclodextrin. Expression of CD39 and CD73 in porcine TM cells and tissue were examined by Q-PCR and Western blot. The effect of inhibition of CD73 on outflow facility was evaluated in perfused living mouse eyes. RESULTS: PTM cells generated extracellular adenosine from extracellular ATP and AMP but not from extracellular cAMP. Increased intracellular cAMP mediated by forskolin led to a significant increase in extracellular adenosine production that was not prevented by IBMX. Inhibition of CD73 resulted, in all cases, in a significant decrease in extracellular adenosine. CMS induced a significant activation of extracellular adenosine production. Inhibition of CD73 activity with AMPCP in living mouse eyes resulted in a significant decrease in outflow facility. CONCLUSIONS: These results support the concept that the extracellular adenosine pathway might play an important role in the homeostatic regulation of outflow resistance in the TM, and suggest a novel mechanism by which pathologic alteration of the TM, such as increased tissue rigidity, could lead to abnormal elevation of IOP in glaucoma.

Benefit from bevacizumab for macular edema in central retinal vein occlusion: twelve-month results of a prospective, randomized study.

PURPOSE: To evaluate the efficacy of intraocular injections with bevacizumab over 12 months in patients with macular edema (ME) secondary to central retinal vein occlusion (CRVO). DESIGN: A prospective study including a randomized 6-month, sham injection-controlled, double-masked clinical trial followed by a 6-month open-label extension. PARTICIPANTS: Sixty patients with ME secondary to CRVO. METHODS: At baseline, patients were randomized 1:1 to receive intraocular injections of bevacizumab or sham injections every 6 weeks for 6 months. From month 6, all patients received intraocular injections of bevacizumab every 6 weeks for 6 months. MAIN OUTCOME MEASURES: The primary outcome measure was the proportion of patients gaining at least 15 letters at 12 months. Secondary outcome measures included mean change from baseline best-corrected visual acuity (BCVA), change in foveal thickness, and development of neovascular glaucoma. RESULTS: At the end of follow-up, 18 of 30 patients (60.0%) in the bevacizumab/bevacizumab (bz/bz) group had gained ≥ 15 letters compared with 10 of 30 patients (33.3%) in the sham/bevacizumab (sh/bz) group (P < 0.05). The BCVA improved by 16.0 letters at 12 months in the bz/bz group compared with 4.6 letters in the sh/bz group (P < 0.05). In an unplanned retrospective analysis, patients aged >70 years had a significantly worse outcome when receiving delayed treatment, losing 1.4 letters (95% confidence interval [CI], -9.7 to 8.4) in the sh/bz group compared with a gain of 20.1 letters (95% CI, 13.9-26.3) in the bz/bz group in patients aged <70 years (P < 0.003). The mean decrease in central retinal thickness (CRT) was 435 µm in the bz/bz group compared with 404 µm in the sh/bz group (P = not significant). No patients developed iris rubeosis during the 6-month open-label extension period. There were no events of endophthalmitis, retinal tear, or retinal detachment during the 12-month treatment period. No serious nonocular adverse events were reported. CONCLUSIONS: Intraocular injections of bevacizumab given every 6 weeks for 12 months improve visual acuity (VA) and reduce ME significantly. Patients receiving delayed treatment have a limited visual improvement. FINANCIAL DISCLOSURE(S): Proprietary or commercial disclosure may be found after the references.

Up-regulated expression of extracellular matrix remodeling genes in phagocytically challenged trabecular meshwork cells.

BACKGROUND: Cells in the trabecular meshwork (TM), the tissue responsible for draining aqueous humor out of the eye, are known to be highly phagocytic. Phagocytic function in TM cells is thought to play an important role in the normal functioning of the outflow pathway. Dysfunction of phagocytosis could lead to abnormalities of outflow resistance and increased intraocular pressure (IOP). However, the molecular mechanisms triggered by phagocytosis in TM cells are completely unknown. METHODOLOGY/PRINCIPAL FINDINGS: Gene expression profile analysis of human TM cells phagocytically challenged to E. coli or pigment under physiological and oxidative stress environment were performed using Affymetrix U133 plus 2.0 array and analyzed with Genespring GX. Despite the differential biological response elicited by E. coli and pigment particles, a number of genes, including MMP1, MMP3, TNFSF11, DIO2, KYNU, and KCCN2 showed differential expression with both phagocytic ligands in all conditions. Data was confirmed by qPCR in both human and porcine TM cells. Metacore pathway analysis and the usage of recombinant adenovirus encoding the dominant negative mutant of IkB identified NF-κB as a transcription factor mediating the up-regulation of at least MMP1 and MMP3 in TM cells with phagocytosis. In-gel zymography demonstrated increased collagenolytic and caseinolytic activities in the culture media of TM cells challenge to E. coli. In addition, collagenolytic I activity was further confirmed using the self-quenched fluorescent substrate DQ-Collagen I. CONCLUSIONS/SIGNIFICANCE: Here we report for the first time the differential gene expression profile of TM cells phagocytically challenged with either E. coli or pigment. Our data indicate a potential role of phagocytosis in outflow pathway tissue homeostasis through the up-regulation and/or proteolytic activation of extracellular matrix remodeling genes.

Bevacizumab for macular edema in central retinal vein occlusion: a prospective, randomized, double-masked clinical study.

PURPOSE: To evaluate the efficacy of intraocular injections with bevacizumab in patients with macular edema (ME) secondary to central retinal vein occlusion (CRVO). DESIGN: Prospective, randomized, sham injection-controlled, double-masked clinical trial. PARTICIPANTS: Sixty patients with ME secondary to CRVO. METHODS: At baseline, patients were randomized 1:1 to receive intraocular injections of bevacizumab or sham injections every 6 weeks for 6 months. MAIN OUTCOME MEASURES: The primary outcome measure was the proportion of patients gaining at least 15 letters at 6 months. Secondary outcome measures included mean change from baseline best-corrected visual acuity (BCVA), foveal thickness, and neovascular glaucoma. RESULTS: At the end of follow-up, 18 of 30 patients (60.0%) in the study group had gained ≥15 letters compared with 6 of 30 patients (20.0%) in the control group (P=0.003). The BCVA improved by 14.1 letters at 24 weeks compared with a decrease of 2.0 letters in the control group (P < 0.003). The mean decrease in central retinal thickness (CRT) was significantly greater in the study group (426 µm) than in the control group (102 µm) at all time points up to week 24 (P < 0.001). No residual edema, defined as CRT <300 µm at 24 weeks, was found in 26 of 30 patients (86.7%) in the treatment group compared with 6 of 30 patients (20%) in the control group (P < 0.001). In the sham group, 5 of 30 patients (16.7%) had developed iris rubeosis at week 24. No patients in the study group had rubeosis at week 24 (P=0.052). There were no events of endophthalmitis, retinal tear, or retinal detachment during the 24-week treatment period. No serious non-ocular adverse events were reported. CONCLUSIONS: Intraocular injections of bevacizumab given every 6 weeks for 6 months improve visual acuity (VA) and reduce ME significantly compared with sham. FINANCIAL DISCLOSURE(S): Proprietary or commercial disclosure may be found after the references.

Resveratrol prevention of oxidative stress damage to lens epithelial cell cultures is mediated by forkhead box O activity.

PURPOSE: To evaluate the potential role that FoxO transcription factors play in modulating resveratrol's protective effects against oxidative stress in lens epithelial cells. METHODS: Primary human or porcine lens epithelial cells (LECs) were treated with resveratrol (RES) 25 µM and incubated under either physiologic (5%) or chronic hyperoxic (40%) oxygen conditions. Acute oxidative stress was applied using 600 µM H(2)O(2). Changes in expression of FoxO1A, FoxO3A, and FoxO4 were analyzed. The production of intracellular reactive oxygen species (iROS), SA-ß-galactosidase (SA-ß-gal) activity, and autofluorescence (AF) was assessed by flow cytometry. SiRNAs of FoxO1A, FoxO3A, and FoxO4 were used to study the roles that these transcription factors play in resveratrol's protective effects against cell death induced by oxidative stress. RESULTS: RES incubation under 40% oxygen increased the expression of FoxO1A, FoxO3A, and FoxO4. RES also increases mitochondrial membrane potential under 5% and/or 40% O(2) conditions and significantly decreased iROS, SA-ß-gal, and AF normally induced by hyperoxic conditions. While RES had a mild pro-apoptotic effect in nonstressed cells, it significantly prevented apoptosis induced by H(2)O(2) stress. SiRNA inhibition of FoxO1A, FoxO3A, and FoxO4 not only led to loss of the anti-apoptotic effects of RES in stressed cells but actually exhibited a mild pro-apoptotic effect. CONCLUSIONS: RES exerts a protective effect against oxidative damage in LEC cultures. The levels of expression of FoxO1A, FoxO3A, and FoxO4 appear to play a central role in determining the pro- or anti-apoptotic effects of RES. This has implications for future studies on oxidative stress-related lenticular disorders such as cataract formation.

Cross-talk between miR-29 and transforming growth factor-betas in trabecular meshwork cells.

PURPOSE: To investigate the interactions between microRNA-29 (miR-29), a negative regulator of extracellular matrix (ECM), and transforming growth factors (TGF)ß-1 and TGFß-2. METHODS: Changes in expression of the miR-29 family were analyzed by quantitative-PCR (Q-PCR) after treatment with TGFß1 and TGFß2 (1 ng/mL). TGFß1 and TGFß2 were evaluated at gene expression and protein levels by Q-PCR and ELISA, respectively, in human trabecular meshwork (HTM) cells transfected with miR-29b or scramble control. TGFß1 promoter activity was analyzed using an adenovirus with the reporter SEAP. The effects of miR-29b and TGFß2 on ECM gene expression were evaluated in cells transfected with miR-29b or scramble control and treated with TGFß2, and the expression of ECM genes was analyzed by Q-PCR. RESULTS: TGFß2 but not TGFß1, downregulated the three members of the miR-29 family. Overexpression of miR-29b antagonized the effects of TGFß2 on the expression of several ECM components. MiR-29b decreased the expression of TGFß1 at the promoter, transcript, and protein levels but had only a minor effect on the expression of active TGFß2. The inhibition of TGFß1 by miR-29b was partially recovered after co-transfection with a plasmid-expressing bone morphogenetic protein 1. CONCLUSIONS: Results showed some level of crosstalk between TGFßs and miR-29. Specifically, the downregulation of miR-29 by TGFß2 contributed to the induction of several ECM components by this cytokine in TM cells. This observation, together with the inhibitory effects of miR-29b on the expression of TGFß1, suggests that the miR-29 family could play an important role in modulating TGFßs on the outflow pathway.

LOXL1 expression in lens capsule tissue specimens from individuals with pseudoexfoliation syndrome and glaucoma.

PURPOSE: To study lysyl oxidase-like 1 (LOXL1) expression in freshly collected lens capsules from pseudoexfoliation syndrome (XFS), pseudoexfoliation glaucoma (XFG), and normal cataract control individuals. We also investigated the effects of four glaucoma drug medications on LOXL1 expression in primary human lens epithelial cell cultures to see if they could affect LOXL1 expression. METHODS: Lens capsules were collected at the time of cataract surgery. Controls were matched to age, sex, and ethnicity. Total RNA was isolated from individual lens capsule samples and real-time PCR was performed on each sample using primers flanking the sixth exon of the LOXL1 gene. Cell cultures were grown to confluence in four separate six-well plates at 37 °C in 5% CO2. Each plate was then treated with one of four different glaucoma drugs (brinzolamide 1%, brimonidine tartrate 0.1%, timolol maleate 0.5%, and latanoprost 0.005%) once daily for seven days (at both 1:1,000 and 1:100 concentrations relative to media). Controls were not treated with any drug but media was changed in the same manner. After one week of treatment, cells were harvested and total RNA isolated. Real-time PCR was performed on each group of cells. RESULTS: Seven XFS, seven XFG, and ten cataract control specimens were analyzed. LOXL1 expression was detected in the lens capsule specimens from each of the four groups. Significant expression differences were found between the control and XFG groups and XFS and XFG groups. No significant difference was observed between the control and XFS group. No significant decrease in LOXL1 expression was seen with drug incubation of the four medications (Brinzolamide, Timolol, Latanoprost, and Brimonidine) at the 1:1,000 drug:media concentrations versus controls. At 10-fold higher concentrations (1:100 drug:media), brinzolamide, timolol maleate, and latanoprost showed small increases in LOXL1 expression relative to controls. This effect was not observed with brimonidine tartrate. CONCLUSIONS: These results establish that LOXL1 expression is reduced in lens capsule specimens from XFG individuals but not XFS. The drug treatment incubation studies suggest that the change in LOXL1 expression observed in XFG is not attributable to glaucoma drug therapy. If a causative functional relationship can be validated, modification of LOXL1 expression in affected tissues may represent a novel treatment strategy for this disorder.

Intralysosomal iron induces lysosomal membrane permeabilization and cathepsin D-mediated cell death in trabecular meshwork cells exposed to oxidative stress.

PURPOSE: To investigate the role of intralysosomal redox-active iron in oxidative stress-induced damage in trabecular meshwork (TM) cells. METHODS: Chronic oxidative stress was applied using the hyperoxic model; acute oxidative stress was applied with H(2)O(2). Microarray analysis was performed using microarrays. mRNA and protein levels were quantified by real-time PCR and Western blot analysis, respectively. Redox-active iron was monitored using calcein-AM. Apoptosis was quantified using double staining. DNA damage was evaluated by single-cell gel electrophoresis assay. Lysosomal permeabilization was monitored using uptake and acridine orange relocation techniques. Intracellular ROS production was quantified using H(2)DCFDA. Cytosolic translocation of cathepsins was visualized with pepstatin-A-BODIPY-FL. Chemical inhibition of cathepsins was achieved with leupeptin and pepstatin A. Silencing of cathepsin expression was accomplished with miRNA sequences. Lysosomal iron chelation was achieved with desferrioxamine. RESULTS: Chronically stressed TM cells showed elevated levels of redox-active iron and altered expression of genes involved in intracellular iron homeostasis. Although iron increased ROS production and lipofuscin levels and sensitized TM cells to H(2)O(2), intralysosomal iron chelation completely protected the cells against H(2)O(2)-induced cell death and apoptosis. The protective effect of desferrioxamine was mediated by the prevention of lysosomal ROS generation and the rupture of lysosomal membrane, with the subsequent release of cathepsin D into the cytosol. CONCLUSIONS: These results indicate that the generation of intralysosomal ROS induces lysosomal membrane permeabilization and the release of cathepsin D into the cytosol, leading to TM cell death. Here, the authors propose a mechanism by which oxidative stress might contribute to the decrease in cellularity reported in the TM tissue with both aging and disease.

Modulation of inflammatory markers by miR-146a during replicative senescence in trabecular meshwork cells.

PURPOSE: To investigate the alterations in microRNA (miRNA) expression during replicative senescence (RS) in human trabecular meshwork (HTM) cells. METHODS: Two HTM cell lines were serially passaged until they reached RS. Changes in expression of 30 miRNAs were assessed by real-time quantitative (q)-PCR. The effects of miR-146a on gene expression were analyzed with gene arrays and the results confirmed by real-time q-PCR. Protein levels of IRAK1 and PAI-1 were analyzed by Western blot and those of IL6 and IL8 by ELISA. Senescence-associated markers were monitored by flow cytometry and cell proliferation by BrdU incorporation. RESULTS: RS of HTM cells was associated with significant changes in expression of 18 miRNAs, including the upregulation of miR-146a. miR-146a downregulated multiple genes associated with inflammation, including IRAK1, IL6, IL8, and PAI-1, inhibited senescence-associated beta-galactosidase (SA-beta-gal) activity and production of intracellular reactive species (iROS), and increased cell proliferation. Overexpression of either IRAK1 or PAI-1 inhibited the effects of miR-146a on cell proliferation and iROS production in senescent cells. CONCLUSIONS: RS in HTM cells was associated with changes in miRNA expression that could influence the senescent phenotype. Upregulation of the anti-inflammatory miR-146a may serve to restrain excessive production of inflammatory mediators in senescent cells and limit their deleterious effects on the surrounding tissue. Among the different proteins repressed by miR-146a, the inhibition of PAI-1 may act to minimize the effects of senescence on the generation of iROS and growth arrest and prevent alterations of the extracellular proteolytic activity of the TM.

Targeting of integrin beta1 and kinesin 2alpha by microRNA 183.

MicroRNA 183 (miR-183) has been reported to inhibit tumor invasiveness and is believed to be involved in the development and function of ciliated neurosensory organs. We have recently found that expression of miR-183 increased after the induction of cellular senescence by exposure to H(2)O(2). To gain insight into the biological roles of miR-183 we investigated two potential novel targets: integrin beta1 (ITGB1) and kinesin 2alpha (KIF2A). miR-183 significantly decreased the expression of ITGB1 and KIF2A measured by Western blot. Targeting of the 3'-untranslated region (3'-UTR) of ITGB1 and KIF2A by miR-183 was confirmed by luciferase assay. Transfection with miR-183 led to a significant decrease in cell invasion and migration capacities of HeLa cells that could be rescued by expression of ITGB1 lacking the 3'-UTR. Although miR-183 had no effects on cell adhesion in HeLa cells, it significantly decreased adhesion to laminin, gelatin, and collagen type I in normal human diploid fibroblasts and human trabecular meshwork cells. These effects were also rescued by expression of ITGB1 lacking the 3'-UTR. Targeting of KIF2A by miR-183 resulted in some increase in the formation of cells with monopolar spindles in HeLa cells but not in human diploid fibroblast or human trabecular meshwork cells. The regulation of ITGB1 expression by miR-183 provides a new mechanism for the anti-metastatic role of miR-183 and suggests that this miRNA could influence the development and function in neurosensory organs, and contribute to functional alterations associated with cellular senescence in human diploid fibroblasts and human trabecular meshwork cells.

Alterations in microRNA expression in stress-induced cellular senescence.

We investigated miRNA expression changes associated with stress-induced premature senescence (SIPS) in primary cultures of human diploid fibroblast (HDF) and human trabecular meshwork (HTM) cells. Twenty-five miRNAs were identified by miRNA microarray analysis and their changes in expression were validated by TaqMan real-time RT-PCR in three independent cell lines of HTM and HDF. SIPS in both HTM and HDF cell types was associated with significant down-regulation of four members of the miR-15 family and five miRNAs of the miR-106b family located in the oncogenic clusters miR-17-92, miR-106a-363, and miR-106b-25. SIPS was also associated with up-regulation of two miRNAs (182 and 183) from the miR-183-96-182 cluster. Transfection with miR-106a agomir inhibited the up-regulation of p21(CDKN1A) associated with SIPS while transfection with miR-106a antagomir led to increased p21(CDKN1A) expression in senescent cells. In addition, we identified retinoic acid receptor gamma (RARG) as a target of miR-182 and showed that this protein was down-regulated during SIPS in HDF and HTM cells. These results suggest that changes in miRNA expression might contribute to phenotypic alterations of senescent cells by modulating the expression of key regulatory proteins such as p21(CDKN1A) as well as by targeting genes that are down-regulated in senescent cells such as RARG.

Extracellular release of ATP mediated by cyclic mechanical stress leads to mobilization of AA in trabecular meshwork cells.

PURPOSE: To investigate the mechanisms that mediate the release of ATP induced by cyclic mechanical stress (CMS) and the role of extracellular ATP in the mobilization of arachidonic acid (AA) and prostaglandin secretion. METHODS: Porcine trabecular meshwork (pTM) cells were subjected to CMS. Extracellular ATP was detected with a luciferin-luciferase assay in the presence or absence of transport inhibitors and a lipid raft disrupter. ATP vesicles were visualized with quinacrine. The release of AA (AA 1-14C) was measured with and without ATP, ATP inhibitors, and phospholipase-A and -C inhibitors. Prostaglandin E2 (PGE2) and viability were measured with ELISA and a lactate dehydrogenase assay, respectively. RESULTS: CMS induced ATP release that was inhibited by the vesicle inhibitors N-ethylmaleimide (NEM) and monensin. Lipid raft disruption significantly increased the extracellular ATP induced by CMS. CMS induced AA release (1-4-fold increase) and its metabolic product PGE2 (3.9-fold increase). The AA mobilization induced by CMS could be mimicked by the addition of extracellular ATP and was partially inhibited by a P2 antagonist, by an ATP inhibitor, and by inhibitors of phospholipase-A2 and -C. Addition of PGE2 (10 microM) to the media exerted cytoprotective effects against long-term CMS. CONCLUSIONS: Extracellular release of ATP induced by CMS in TM cells is mediated by exocytosis of ATP-enriched vesicles into lipid rafts. The resulting activation of purinergic receptors leads to mobilization of AA from the plasma membrane. The subsequent release of PGE could exert protective effects by preventing TM cell loss that may result from chronic exposure to CMS.

Eyedrops containing SA9000 prodrugs result in sustained reductions in intraocular pressure in rabbits.

AIM: Poor topical bioavailability and ocular irritation have impeded the development of the diuretic, ethacrynic acid (ECA) as a clinically useful ocular hypotensive for the treatment of glaucoma. Thus, the development of analogs and prodrugs of analogs with improved ocular penetration, potency, and tolerability is required. The aim of this work is to evaluate the corneal penetration and ocular distribution of SA9000, an ECA analog. Novel SA9000 prodrugs intended to further improve ocular pharmacodynamic effect were also evaluated. RESULTS: SA9000 penetrated porcine corneas more effectively than ECA in corneal diffusion studies. In vivo studies in Dutch-belted (DB) rabbits indicated that topical application of a single dose (0.3%) of SA9000 could significantly reduce intraocular pressure (IOP) (approximately 25% vs. fellow untreated eye) but caused significant conjunctival hyperemia. Since this hyperemia was likely the result of its inherent thiol reactivity, SA9000 was formulated with equimolar cysteine, an exogenous thiol donor. The administration of increasing SA9000-cysteine adduct concentrations (0.3%, 0.6%, 0.9%) demonstrated that they cause less ocular irritation than unadducted SA9000 but could still significantly reduce IOP (0.3%: 8.7 +/- 2%; 0.6%: 14.4 +/- 5%; 0.9%: 23.3 +/- 4.4%) versus untreated contralateral control eyes. CONCLUSIONS: These data suggest that novel thiol donor adduction can improve the ocular bioavailability and tolerability of SA9000. SA9000-cysteine prodrugs may represent a new option for the topical treatment of glaucoma.

Cross-talk between TGF-beta1 and IL-6 in human trabecular meshwork cells.

PURPOSE: To investigate the relationship between transforming growth factor beta-1 (TGF-beta1) and interleukin-6 (IL-6) in human trabecular meshwork (HTM) cells as well as to identify the signaling pathway/s involved in the increased IL-6 expression that occurs in response to mechanical stress and TGF-beta1. METHODS: All experiments were performed in confluent monolayers of HTM cells at passage 3. Secreted IL-6 was quantified by ELISA. Levels of IL-6 mRNA were evaluated by polymerase chain reaction (PCR) analysis. Activation of the IL-6 and TGF-beta1 promoters was monitored by measuring secreted alkaline phosphatase protein (SEAP) released into the culture medium by HTM cells infected with an adenovirus expressing the SEAP reporter gene that was controlled by either the IL-6 promoter (AdIL6-SEAP) or the TGF-beta1 promoter (AdTGFbeta1-SEAP). Cyclic mechanical stress (5% elongation, one cycle per second) was applied using the Flexcell System. Reagents used in this study included human TGF-beta1, human IL-6, and the inhibitors for the p38 mitogen-activated protein kinase (MAPK; SB202190), c-jun NH2-terminal kinase (JNK; SP600125), extracellular-regulating kinase (ERK; PD98059), and TGF type I activin receptor (SB431542). RESULTS: Incubation of HTM cells with TGF-beta1 (5 ng/ml) resulted in a significant increase in the protein and mRNA levels of IL-6, which was significantly diminished in the presence of the inhibitors for p38 MAPK or JNK. No transcriptional activation of the exogenous IL-6 promoter was observed following TGF-beta1 treatment. In addition, the presence of inhibitors for the p38 MAPK, ERK, and TGF-beta1 pathways significantly decreased the increased expression of IL-6 by cyclic mechanical stress. Furthermore, exposure of HTM cells to IL-6 (100 ng/ml) demonstrated the transcriptional activation of TGF-beta1 promoter, which was severely impaired by blocking the p38 MAPK pathway. CONCLUSIONS: Our results indicate that TGF-beta1 participates in the regulation of basal expression and the stretch-induced expression of IL-6 and suggest the possible existence in cultured HTM cells of an autocrine loop between IL-6 and TGF-beta1. We also found that p38 MAPK might play a contributing role in the maintenance of such a loop.

Induction of IL-6 expression by mechanical stress in the trabecular meshwork.

The trabecular meshwork (TM)/Schlemm's canal (SC) outflow pathway is the tissue responsible for maintaining normal levels of intraocular pressure. In the present study, we investigate the effects of mechanical stress on the expression of IL-6 in the TM meshwork, as well as the effects of this cytokine on outflow pathway function. Application of cyclic mechanical stress to human TM primary cultures resulted in a statistically significant increase in both secretion and transcription of IL-6, compared to nonstressed controls. Addition of TGF-beta1, which has been reported to be upregulated in TM cells under mechanical stress, also induced a significant activation of both the transcription and secretion of IL-6. Moreover, anti-TGF-b1 antibodies partially blocked the stretch-induced IL-6 production. Injection of IL-6 into perfused porcine anterior segments resulted in a 30% increase in outflow facility, as well as increased permeability through SC cell monolayers. These results suggest a role for IL-6 in the homeostatic modulation of aqueous humor outflow resistance.

High failure rate associated with 180 degrees selective laser trabeculoplasty.

PURPOSE: To determine the efficacy of selective laser trabeculoplasty (SLT) in a tertiary care referral center. PATIENTS AND METHODS: In this retrospective study of selective laser trabeculoplasty performed by five physicians, 94 eyes from 94 patients were included. A majority (83/92, 90%) underwent 180 degrees selective laser trabeculoplasty. Selective laser trabeculoplasty failure was defined in two ways: (1) IOP decrease <3 mm Hg (definition one), or (2) IOP decrease <20% (definition two), on two successive visits > or =4 weeks after SLT. RESULTS: Overall failure rates were 68% (64/94) and 75% (70/94) (by definitions one and two, respectively). By survival/life-table analysis, mean time to failure was 6 months and 5.5 months, by definitions one and two, respectively. By the end of the study (14.5 months), the failure rates were 86% and 92% by definitions one and two, respectively. By each definition, in both univariable and multivariable analysis, only lower baseline IOP was a significant predictor of failure. CONCLUSIONS: Selective laser trabeculoplasty had an overall low success rate in our tertiary clinic population, with overall failure rates of 68% to 74% in those who underwent 180 degrees selective laser trabeculoplasty.