Targeting YAP/TAZ mechanosignaling to ameliorate stiffness-induced Schlemm's canal cell pathobiology.

Pathological alterations in the biomechanical properties of the Schlemm's canal (SC) inner wall endothelium and its immediate vicinity are strongly associated with ocular hypertension in glaucoma due to decreased outflow facility. Specifically, the underlying trabecular meshwork is substantially stiffer in glaucomatous eyes compared with that from normal eyes. This raises the possibility of a critical involvement of mechanotransduction processes in driving SC cell dysfunction. Yes-associated protein (YAP) has emerged as a key contributor to glaucoma pathogenesis. However, the molecular underpinnings of SC cell mechanosignaling via YAP and transcriptional coactivator with PDZ-binding motif (TAZ) in response to glaucomatous extracellular matrix (ECM) stiffening are not well understood. Using a novel biopolymer hydrogel that facilitates dynamic and reversible stiffness tuning, we investigated how ECM stiffening modulates YAP/TAZ activity in primary human SC cells, and whether disruption of YAP/TAZ mechanosignaling attenuates SC cell pathobiology and increases ex vivo outflow facility. We demonstrated that ECM stiffening drives pathologic YAP/TAZ activation and cytoskeletal reorganization in SC cells, which was fully reversible by matrix softening in a distinct time-dependent manner. Furthermore, we showed that pharmacologic or genetic disruption of YAP/TAZ mechanosignaling abrogates stiffness-induced SC cell dysfunction involving altered cytoskeletal and ECM remodeling. Finally, we found that perfusion of the clinically used, small molecule YAP/TAZ inhibitor verteporfin (without light activation) increases ex vivo outflow facility in normal mouse eyes. Collectively, our data provide new evidence for a pathologic role of aberrant YAP/TAZ mechanosignaling in SC cell dysfunction and suggest that YAP/TAZ inhibition has therapeutic value for treating ocular hypertension in glaucoma.NEW & NOTEWORTHY Pathologically altered biomechanical properties of the Schlemm's canal (SC) inner wall microenvironment were recently validated as the cause for increased outflow resistance in ocular hypertensive glaucoma. However, the involvement of specific mechanotransduction pathways in these disease processes is largely unclear. Here, we demonstrate that Yes-associated protein (YAP)/transcriptional coactivator with PDZ-binding motif (TAZ) are central regulators of glaucoma-like SC cell dysfunction in response to extracellular matrix stiffening and that targeted disruption of YAP/TAZ mechanosignaling attenuates SC cell pathobiology and enhances outflow function.

Association between ADHD and vision problems. A systematic review and meta-analysis.

AIM: To conduct the first systematic review and meta-analysis assessing whether attention-deficit/hyperactivity disorder (ADHD) is associated with disorders of the eye, and/or altered measures of visual function. METHOD: Based on a pre-registered protocol (PROSPERO: CRD42021256352), we searched PubMed, Web of Knowledge/Science, Ovid Medline, Embase and APA PsycINFO up to 16th November 2021, with no language/type of document restrictions. We included observational studies reporting at least one measure of vision in people of any age meeting DSM/ICD criteria for ADHD and in people without ADHD; or the prevalence of ADHD in people with and without vision disorders. Study quality was assessed with the Appraisal tool for Cross-Sectional Studies (AXIS). Random effects meta-analyses were used for data synthesis. RESULTS: We included 42 studies in the narrative synthesis and 35 studies in the meta-analyses (3,250,905 participants). We found meta-analytic evidence of increased risk of astigmatism (OR = 1.79 [CI: 1.50, 2.14]), hyperopia and hypermetropia (OR = 1.79 [CI: 1.66, 1.94]), strabismus (OR = 1.93 [CI: 1.75, 2.12]), unspecified vision problems (OR = 1.94 [CI: 1.38, 2.73]) and reduced near point of convergence (OR = 5.02 [CI: 1.78, 14.11]); increased lag (Hedge's g = 0.63 [CI: 0.30, 0.96]) and variability (Hedge's g = 0.40 [CI: 0.17, 0.64]) of the accommodative response; and increased self-reported vision problems (Hedge's g = 0.63 [CI: 0.44, 0.82]) in people with ADHD compared to those without ADHD (with no significant heterogeneity). We also found meta-analytic evidence of no differences between people with and without ADHD on retinal nerve fiber layer thickness (Hedge's g = -0.19 [CI: -0.41, 0.02]) and refractive error (Hedge's g = 0.08 [CI: -0.26, 0.42]) (with no significant heterogeneity). DISCUSSION: ADHD is associated with some self-reported and objectively ascertained functional vision problems, but not with structural alterations of the eye. Further studies should clarify the causal relationship, if any, between ADHD and problems of vision. TRIAL REGISTRATION: PROSPERO registration: CRD42021256352.

Association between Autism Spectrum Disorder (ASD) and vision problems. A systematic review and meta-analysis.

AIM: To conduct a systematic review and meta-analysis assessing whether vision and/or eye disorders are associated with Autism Spectrum Disorder (ASD). METHOD: Based on a pre-registered protocol (PROSPERO: CRD42022328485), we searched PubMed, Web of Knowledge/Science, Ovid Medline, Embase and APA PsycINFO up to 5th February 2022, with no language/type of document restrictions. We included observational studies 1) reporting at least one measure of vision in people of any age with a diagnosis of ASD based on DSM or ICD criteria, or ADOS; or 2) reporting the prevalence of ASD in people with and without vision disorders. Study quality was assessed with the Appraisal tool for Cross-Sectional Studies (AXIS). Random-effects meta-analyses were used for data synthesis. RESULTS: We included 49 studies in the narrative synthesis and 46 studies in the meta-analyses (15,629,159 individuals distributed across multiple different measures). We found meta-analytic evidence of increased prevalence of strabismus (OR = 4.72 [95% CI: 4.60, 4.85]) in people with versus those without ASD (non-significant heterogeneity: Q = 1.0545, p = 0.7881). We also found evidence of increased accommodation deficits (Hedge's g = 0.68 [CI: 0.28, 1.08]) (non-significant heterogeneity: Q = 6.9331, p = 0.0741), reduced peripheral vision (-0.82 [CI: -1.32, -0.33]) (non-significant heterogeneity: Q = 4.8075, p = 0.4398), reduced stereoacuity (0.73 [CI: -1.14, -0.31]) (non-significant heterogeneity: Q = 0.8974, p = 0.3435), increased color discrimination difficulties (0.69 [CI: 0.27,1.10]) (non-significant heterogeneity: Q = 9.9928, p = 0.1890), reduced contrast sensitivity (0.45 [CI: -0.60, -0.30]) (non-significant heterogeneity: Q = 9.9928, p = 0.1890) and increased retinal thickness (=0.29 [CI: 0.07, 0.51]) (non-significant heterogeneity: Q = 0.8113, p = 0.9918) in ASD. DISCUSSION: ASD is associated with some self-reported and objectively measured functional vision problems, and structural alterations of the eye, even though we observed several methodological limitations in the individual studies included in our meta-analyses. Further research should clarify the causal relationship, if any, between ASD and problems of vision during early life. PROSPERO REGISTRATION: CRD42022328485.

Engineering a 3D hydrogel system to study optic nerve head astrocyte morphology and behavior.

In glaucoma, astrocytes within the optic nerve head (ONH) rearrange their actin cytoskeleton, while becoming reactive and upregulating intermediate filament glial fibrillary acidic protein (GFAP). Increased transforming growth factor beta 2 (TGF ß2) levels have been implicated in glaucomatous ONH dysfunction. A key limitation of using conventional 2D culture to study ONH astrocyte behavior is the inability to faithfully replicate the in vivo ONH microenvironment. Here, we engineer a 3D ONH astrocyte hydrogel to better mimic in vivo mouse ONH astrocyte (MONHA) morphology, and test induction of MONHA reactivity using TGF ß2. Primary MONHAs were isolated from C57BL/6J mice and cell purity confirmed. To engineer 3D cell-laden hydrogels, MONHAs were mixed with photoactive extracellular matrix components (collagen type I, hyaluronic acid) and crosslinked for 5 minutes using a photoinitiator (0.025% riboflavin) and UV light (405-500 nm, 10.3 mW/cm2). MONHA-encapsulated hydrogels were cultured for 3 weeks, and then treated with TGF ß2 (2.5, 5.0 or 10 ng/ml) for 7 days to assess for reactivity. Following encapsulation, MONHAs retained high cell viability in hydrogels and continued to proliferate over 4 weeks as determined by live/dead staining and MTS assays. Sholl analysis demonstrated that MONHAs within hydrogels developed increasing process complexity with increasing process length over time. Cell processes connected with neighboring cells, coinciding with Connexin43 expression within astrocytic processes. Treatment with TGF ß2 induced reactivity in MONHA-encapsulated hydrogels as determined by altered F-actin cytoskeletal morphology, increased GFAP expression, and elevated fibronectin and collagen IV deposition. Our data sets the stage for future use of this 3D biomimetic ONH astrocyte-encapsulated hydrogel to investigate astrocyte behavior in response to injury.

Mechanosensitive channel inhibition attenuates TGFß2-induced actin cytoskeletal remodeling and reactivity in mouse optic nerve head astrocytes.

Astrocytes within the optic nerve head undergo actin cytoskeletal rearrangement early in glaucoma, which coincides with astrocyte reactivity and extracellular matrix (ECM) deposition. Elevated transforming growth factor beta 2 (TGFß2) levels within astrocytes have been described in glaucoma, and TGFß signaling induces actin cytoskeletal remodeling and ECM deposition in many tissues. A key mechanism by which astrocytes sense and respond to external stimuli is via mechanosensitive ion channels. Here, we tested the hypothesis that inhibition of mechanosensitive channels will attenuate TGFß2-mediated optic nerve head astrocyte actin cytoskeletal remodeling, reactivity, and ECM deposition. Primary optic nerve head astrocytes were isolated from C57BL/6J mice and cell purity was confirmed by immunostaining. Astrocytes were treated with vehicle control, TGFß2 (5 ng/ml), GsMTx4 (a mechanosensitive channel inhibitor; 500 nM), or TGFß2 (5 ng/ml) + GsMTx4 (500 nM) for 48 h. FITC-phalloidin staining was used to assess the formation of f-actin stress fibers and to quantify the presence of crosslinked actin networks (CLANs). Cell reactivity was determined by immunostaining and immunoblotting for GFAP. Levels of fibronectin and collagen IV deposition were also quantified. Primary optic nerve head astrocytes were positive for the astrocyte marker GFAP and negative for markers for microglia (F4/80) and oligodendrocytes (OSP1). Significantly increased %CLAN-positive cells were observed after 48-h treatment with TGFß2 vs. control in a dose-dependent manner. Co-treatment with GsMTx4 significantly decreased %CLAN-positive cells vs. TGFß2 treatment and the presence of f-actin stress fibers. TGFß2 treatment significantly increased GFAP, fibronectin, and collagen IV levels, and GsMTx4 co-treatment ameliorated GFAP immunoreactivity. Our data suggest inhibition of mechanosensitive channel activity as a potential therapeutic strategy to modulate actin cytoskeletal remodeling within the optic nerve head in glaucoma.

A tissue-engineered human trabecular meshwork hydrogel for advanced glaucoma disease modeling.

Abnormal human trabecular meshwork (HTM) cell function and extracellular matrix (ECM) remodeling contribute to HTM stiffening in primary open-angle glaucoma (POAG). Most current cellular HTM model systems do not sufficiently replicate the complex native three dimensional (3D) cell-ECM interface, limiting their use for investigating POAG pathology. Tissue-engineered hydrogels are ideally positioned to overcome shortcomings of current models. Here, we report a novel biomimetic HTM hydrogel and test its utility as a POAG disease model. HTM hydrogels were engineered by mixing normal donor-derived HTM cells with collagen type I, elastin-like polypeptide and hyaluronic acid, each containing photoactive functional groups, followed by UV crosslinking. Glaucomatous conditions were induced with dexamethasone (DEX), and effects of the Rho-associated kinase (ROCK) inhibitor Y27632 on cytoskeletal organization and tissue-level function, contingent on HTM cell-ECM interactions, were assessed. DEX exposure increased HTM hydrogel contractility, f-actin and alpha smooth muscle actin abundance and rearrangement, ECM remodeling, and fibronectin deposition - all contributing to HTM hydrogel condensation and stiffening consistent with glaucomatous HTM tissue behavior. Y27632 treatment produced precisely the opposite effects and attenuated the DEX-induced pathologic changes, resulting in HTM hydrogel relaxation and softening. For model validation, confirmed glaucomatous HTM (GTM) cells were encapsulated; GTM hydrogels showed increased contractility, fibronectin deposition, and stiffening vs. normal HTM hydrogels despite reduced GTM cell proliferation. We have developed a biomimetic HTM hydrogel model for detailed investigation of 3D cell-ECM interactions under normal and simulated glaucomatous conditions. Its bidirectional responsiveness to pharmacological challenge and rescue suggests promising potential to serve as screening platform for new POAG treatments with focus on HTM biomechanics.

Safety and Effectiveness of a Small Incision Lateral Eyebrow Ptosis Repair Technique Using a Frontalis Muscle Transposition Flap.

PURPOSE: To evaluate the safety and effectiveness of a frontalis muscle transposition flap for treatment of lateral eyebrow ptosis. METHODS: The charts of all patients undergoing frontalis muscle transposition flap eyebrow ptosis repair from December 2013 to September 2014 were reviewed. Charts with inadequate photographs were excluded. Charts were reviewed for demographics, preoperative and postoperative photographs, surgical technique, and complications. The following parameters were assessed on preoperative and postoperative photographs: corneal diameter, central brow height, and lateral brow height. Measurements were normalized to a standard corneal diameter of 11.5 mm. Statistical analysis was performed in conjunction with the Cleveland Health Institute Biostatistics Department. RESULTS: Forty-six total patients underwent frontalis muscle transposition flap eyebrow ptosis repair and the charts of 31 patients (53 cases) were reviewed. There were 20 female and 11 male patients. Average age was 69.1 ± 7.7 years (range: 50 - 86 years). There were 9 unilateral and 22 bilateral cases. Concomitant surgeries included upper blepharoplasty (33 cases), conjunctival-Mullerectomy blepharoptosis repair (3 cases), and intralesional tetracycline injection for festoons (3 cases). Average follow-up interval between surgery and the final postoperative photograph was 10.2 weeks (range: 6-26 weeks). Overall, lateral brow height increased postoperatively by 1.78 mm (p < 0.05). In patients that underwent frontalis muscle transposition flap alone, lateral brow height increased by 2.86 mm (p < 0.05). Scalp hypesthesia was documented in 10/31 patients, and resolved in 8/10 patients at last follow up. CONCLUSIONS: A frontalis muscle transposition flap effectively addresses lateral eyebrow ptosis repair through a small, relatively concealed incision. It produces temporary scalp hypesthesia in a significant number of patients, and long-term results remain unknown.

Simvastatin Attenuates Glucocorticoid-Induced Human Trabecular Meshwork Cell Dysfunction via YAP/TAZ Inactivation.

PURPOSE: Impairment of the trabecular meshwork (TM) is the principal cause of increased outflow resistance in the glaucomatous eye. Yes-associated protein (YAP) and transcriptional coactivator with PDZ binding motif (TAZ) are emerging as potential mediators of TM cell/tissue dysfunction. Furthermore, YAP/TAZ activity was recently found to be controlled by the mevalonate pathway in non-ocular cells. Clinically used statins block the mevalonate cascade and were shown to improve TM cell pathobiology; yet, the link to YAP/TAZ signaling was not investigated. In this study, we hypothesized that simvastatin attenuates glucocorticoid-induced human TM (HTM) cell dysfunction via YAP/TAZ inactivation. METHODS: Primary HTM cells were seeded atop or encapsulated within bioengineered extracellular matrix (ECM) hydrogels. Dexamethasone was used to induce a pathologic phenotype in HTM cells in the absence or presence of simvastatin. Changes in YAP/TAZ activity, actin cytoskeletal organization, phospho-myosin light chain levels, hydrogel contraction/stiffness, and fibronectin deposition were assessed. RESULTS: Simvastatin potently blocked pathologic YAP/TAZ nuclear localization/activity, actin stress fiber formation, and myosin light chain phosphorylation in HTM cells. Importantly, simvastatin co-treatment significantly attenuated dexamethasone-induced ECM contraction/stiffening and fibronectin mRNA and protein levels. Sequential treatment was similarly effective but did not match clinically-used Rho kinase inhibition. CONCLUSIONS: YAP/TAZ inactivation with simvastatin attenuates HTM cell pathobiology in a tissue-mimetic ECM microenvironment. Our data may help explain the association of statin use with a reduced risk of developing glaucoma via indirect YAP/TAZ inhibition as a proposed regulatory mechanism.

Targeting YAP mechanosignaling to ameliorate stiffness-induced Schlemm's canal cell pathobiology.

Pathologic alterations in the biomechanical properties of the Schlemm's canal (SC) inner wall endothelium and its immediate vicinity are strongly associated with ocular hypertension in glaucoma due to decreased outflow facility. Specifically, the underlying trabecular meshwork is substantially stiffer in glaucomatous eyes compared to that from normal eyes. This raises the possibility of a critical involvement of mechanotransduction processes in driving SC cell dysfunction. Yes-associated protein (YAP) has emerged as a key contributor to glaucoma pathogenesis. However, the molecular underpinnings of SC cell YAP mechanosignaling in response to glaucomatous extracellular matrix (ECM) stiffening are not well understood. Using a novel biopolymer hydrogel that facilitates dynamic and reversible stiffness tuning, we investigated how ECM stiffening modulates YAP activity in primary human SC cells, and whether disruption of YAP mechanosignaling attenuates SC cell pathobiology and increases ex vivo outflow facility. We demonstrated that ECM stiffening drives pathologic YAP activation and cytoskeletal reorganization in SC cells, which was fully reversible by matrix softening in a distinct time-dependent manner. Furthermore, we showed that pharmacologic or genetic disruption of YAP mechanosignaling abrogates stiffness-induced SC cell dysfunction involving altered cytoskeletal and ECM remodeling. Lastly, we found that perfusion of the clinically-used, small molecule YAP inhibitor verteporfin (without light activation) increases ex vivo outflow facility in normal mouse eyes. Collectively, our data provide new evidence for a pathologic role of aberrant YAP mechanosignaling in SC cell dysfunction and suggest that YAP inhibition has therapeutic value for treating ocular hypertension in glaucoma.

YAP/TAZ Mediate TGFß2-Induced Schlemm's Canal Cell Dysfunction.

Purpose: Elevated transforming growth factor beta2 (TGFß2) levels in the aqueous humor have been linked to glaucomatous outflow tissue dysfunction. Potential mediators of dysfunction are the transcriptional coactivators, Yes-associated protein (YAP) and transcriptional coactivator with PDZ binding motif (TAZ). However, the molecular underpinnings of YAP/TAZ modulation in Schlemm's canal (SC) cells under glaucomatous conditions are not well understood. Here, we investigate how TGFß2 regulates YAP/TAZ activity in human SC (HSC) cells using biomimetic extracellular matrix hydrogels, and examine whether pharmacological YAP/TAZ inhibition would attenuate TGFß2-induced HSC cell dysfunction. Methods: Primary HSC cells were seeded atop photo-cross-linked extracellular matrix hydrogels, made of collagen type I, elastin-like polypeptide and hyaluronic acid, or encapsulated within the hydrogels. HSC cells were induced with TGFß2 in the absence or presence of concurrent actin destabilization or pharmacological YAP/TAZ inhibition. Changes in actin cytoskeletal organization, YAP/TAZ activity, extracellular matrix production, phospho-myosin light chain levels, and hydrogel contraction were assessed. Results: TGFß2 significantly increased YAP/TAZ nuclear localization in HSC cells, which was prevented by either filamentous-actin relaxation or depolymerization. Pharmacological YAP/TAZ inhibition using verteporfin without light stimulation decreased fibronectin expression and actomyosin cytoskeletal rearrangement in HSC cells induced by TGFß2. Similarly, verteporfin significantly attenuated TGFß2-induced HSC cell-encapsulated hydrogel contraction. Conclusions: Our data provide evidence for a pathologic role of aberrant YAP/TAZ signaling in HSC cells under simulated glaucomatous conditions and suggest that pharmacological YAP/TAZ inhibition has promising potential to improve outflow tissue dysfunction.

TGFß2 Regulates Human Trabecular Meshwork Cell Contractility via ERK and ROCK Pathways with Distinct Signaling Crosstalk Dependent on the Culture Substrate.

PURPOSE: Transforming growth factor-beta 2 (TGFß2) is a major contributor to the pathologic changes occurring in human trabecular meshwork (HTM) cells in primary open-angle glaucoma (POAG). TGFß2 activates extracellular-signal-regulated kinase (ERK) and Rho-associated kinase (ROCK) signaling pathways, both affecting HTM cell behavior. However, exactly how these signaling pathways converge to regulate HTM cell contractility is unclear. Here, we investigated the molecular mechanism underlying TGFß2-induced pathologic HTM cell contractility, and the crosstalk between ERK and ROCK signaling pathways with different culture substrates. METHODS: Hydrogels were engineered by mixing collagen type I, elastin-like polypeptide, and hyaluronic acid, each containing photoactive functional groups, followed by UV crosslinking. Primary HTM cells were seeded atop pre-formed hydrogels for comparisons with glass, or encapsulated within the hydrogels. Changes in actin cytoskeleton, extracellular matrix (ECM) production, phospho-myosin light chain (p-MLC) levels, and hydrogel contraction were assessed. RESULTS: HTM cell morphology and filamentous (F)-actin organization were affected by the underlying culture substrates. TGFß2 increased HTM cell contractility via ERK and ROCK signaling pathways by differentially regulating F-actin, α-smooth muscle actin (αSMA), fibronectin (FN), and p-MLC in HTM cells. ERK inhibition, even as short as 4 h, further increased TGFß2-induced p-MLC in HTM cells on hydrogels, but not on glass. This translated into hypercontractility of HTM cell-laden hydrogels. ROCK inhibition had precisely the opposite effects and potently relaxed the TGFß2-induced hydrogels. CONCLUSIONS: Our data suggest that ERK signaling negatively regulates ROCK-mediated HTM cell contractility. These findings emphasize the critical importance of using tissue-mimetic ECM substrates for investigating HTM cell physiology and glaucomatous pathophysiology in vitro.

Extracellular Matrix Stiffness and TGFß2 Regulate YAP/TAZ Activity in Human Trabecular Meshwork Cells.

Primary open-angle glaucoma progression is associated with increased human trabecular meshwork (HTM) stiffness and elevated transforming growth factor beta 2 (TGFß2) levels in the aqueous humor. Increased transcriptional activity of Yes-associated protein (YAP) and transcriptional coactivator with PDZ-binding motif (TAZ), central players in mechanotransduction, are implicated in glaucomatous HTM cell dysfunction. Yet, the detailed mechanisms underlying YAP/TAZ modulation in HTM cells in response to alterations in extracellular matrix (ECM) stiffness and TGFß2 levels are not well understood. Using biomimetic ECM hydrogels with tunable stiffness, here we show that increased ECM stiffness elevates YAP/TAZ nuclear localization potentially through modulating focal adhesions and cytoskeletal rearrangement. Furthermore, TGFß2 increased nuclear YAP/TAZ in both normal and glaucomatous HTM cells, which was prevented by inhibiting extracellular-signal-regulated kinase and Rho-associated kinase signaling pathways. Filamentous (F)-actin depolymerization reversed TGFß2-induced YAP/TAZ nuclear localization. YAP/TAZ depletion using siRNA or verteporfin decreased focal adhesions, ECM remodeling and cell contractile properties. Similarly, YAP/TAZ inactivation with verteporfin partially blocked TGFß2-induced hydrogel contraction and stiffening. Collectively, our data provide evidence for a pathologic role of aberrant YAP/TAZ signaling in glaucomatous HTM cell dysfunction, and may help inform strategies for the development of novel multifactorial approaches to prevent progressive ocular hypertension in glaucoma.

Consensus Recommendation for Mouse Models of Ocular Hypertension to Study Aqueous Humor Outflow and Its Mechanisms.

Due to their similarities in anatomy, physiology, and pharmacology to humans, mice are a valuable model system to study the generation and mechanisms modulating conventional outflow resistance and thus intraocular pressure. In addition, mouse models are critical for understanding the complex nature of conventional outflow homeostasis and dysfunction that results in ocular hypertension. In this review, we describe a set of minimum acceptable standards for developing, characterizing, and utilizing mouse models of open-angle ocular hypertension. We expect that this set of standard practices will increase scientific rigor when using mouse models and will better enable researchers to replicate and build upon previous findings.

Aggressive Initial Presentation of HLA-B27 Uveitis in Older Individuals: A Case Series.

PURPOSE: HLA-B27-associated uveitis is classically thought to be a disease of the young, with a median age of onset in the 30s. There is a paucity of literature reporting on older individuals with HLA-B27 uveitis. Here, we describe cases of HLA-B27 uveitis presenting initially at age ≥70. METHODS: Retrospective review of patients with HLA-B27-associated uveitis that presented initially at ≥70 years of age. RESULTS: Three patients were identified. All presented with aggressive inflammation (hypopyon in two cases) and two were treated for suspected endophthalmitis. All cases were controlled sufficiently with prolonged topical anti-inflammatory therapy. One patient who was lost to follow-up demonstrated one recurrence over a 3-year period. CONCLUSIONS: This series highlights the aggressive initial presentation of HLA-B27-associated uveitis in the older population, and demonstrates the favorable response, and limitation of recurrences, with topical immunosuppressive therapy.

Treatment Duration and Side Effect Profile of Long-Term Use of Intravitreal Preservative-Free Triamcinolone Acetonide in Uveitis.

PURPOSE: Noninfectious uveitis has been treated historically with corticosteroid therapy in varying doses and routes. Triesence, a preservative-free sterile formulation of triamcinolone acetonide, has been used in a wide spectrum of ocular pathologies, but there have been few large studies validating its dosing or detailing long-term side effects in uveitic disease. The primary aim of this study was to describe the relative duration of action and side effects of 2 doses of preservative-free intravitreal triamcinolone acetonide (PF-IVTA) in uveitis. DESIGN: Retrospective, comparative consecutive case series. METHODS: Charts of all patients receiving PF-IVTA (2 mg or 4 mg) in a defined time period (2012-2014) at the Cole Eye Institute were examined for patient demographics, time to treatment failure (TTF), use of systemic immunosuppression, use of intraocular pressure-lowering therapies, date of cataract surgery and glaucoma filtration surgery, and adverse events. RESULTS: The final data set examined 514 injections in 214 eyes. Mean duration of follow-up was 1.5 years. There was similar demographic distribution between eyes that received 2 mg PF-IVTA only and eyes that received a combination of 4 + 2 mg PF-IVTA. No statistically significant difference in TTF between injection dosages was observed. There was a higher incidence of glaucoma filtering surgery and cataract surgery in eyes that received 4 + 2 mg PF-IVTA as well as a shorter time to glaucoma surgery, when compared to eyes that received 2 mg PF-IVTA alone. CONCLUSIONS: This retrospective study supports that 2 mg PF-IVTA displayed noninferior treatment duration to 4 mg PF-IVTA, and may carry a significantly lower side-effect profile of cataract development and glaucoma filtering surgery.

Conjunctival squamous papilloma refractory to interferon α-2b in a patient on systemic immunosuppression (tacrolimus).

PURPOSE: To describe a case of diffuse conjunctival papilloma in an immunocompromised individual on tacrolimus that was refractory to treatment with interferon α-2b, but responded to topical mitomycin-c. OBSERVATIONS: A 79-year-old Caucasian female with a history of a liver transplant twenty years ago, who was immunosuppressed with tacrolimus (2 mg daily) presented with a diffuse conjunctival and corneal squamous papilloma. Following treatment with four weekly subconjunctival interferon-α2b injections (3 million units/0.5 mL) and 3 months of topical interferon-α2b therapy (1 million units/mL), four times daily, slow progression was documented. The patient was switched to topical mitomycin-c drops (0.04%) administered four times daily (one week on and one week off) with dramatic regression of the tumor. CONCLUSIONS AND IMPORTANCE: In cases of conjunctival squamous papilloma that do not respond readily to topical interferon, topical mitomycin-c is an alternate therapeutic option. We hypothesize that use of tacrolimus may have contributed to the lack of response to topical interferon-α2b.

Alterations of retinal vasculature in cystathionine-Beta-synthase mutant mice, a model of hyperhomocysteinemia.

PURPOSE: Mice with moderate/severe hyperhomocysteinemia due to deficiency or absence of the cbs gene encoding cystathionine-beta-synthase (CBS) have marked retinal disruption, ganglion cell loss, optic nerve mitochondrial dysfunction, and ERG defects; those with mild hyperhomocysteinemia have delayed retinal morphological/functional phenotype. Excess homocysteine is a risk factor for cardiovascular diseases; however, it is not known whether excess homocysteine alters retinal vasculature. METHODS: Cbs(+/+), cbs(+/-), and cbs(-/-) mice (age ∼3 weeks) were subjected to angiography; retinas were harvested for cryosections, flat-mount preparations, or trypsin digestion and subjected to immunofluorescence microscopy to visualize vessels using isolectin-B4, to detect angiogenesis using anti-VEGF and anti-endoglin (anti-CD105) and activated glial cells (anti-glial fibrillary acidic protein [anti-GFAP]) and to investigate the blood-retinal barrier using the tight junction markers zonula occludens-1 (ZO-1) and occludin. Expression of vegf was determined by quantitative RT-PCR (qRT-PCR) and immunoblotting. Human retinal endothelial cells (HRECs) were treated with excess homocysteine to analyze permeability. RESULTS: Angiography revealed vascular leakage in cbs(-/-) mice; immunohistochemical analysis demonstrated vascular patterns consistent with ischemia; isolectin-B4 labeling revealed a capillary-free zone centrally and new vessels with capillary tufts midperipherally. This was associated with increased vegf mRNA and protein, CD105, and GFAP in cbs(-/-) retinas concomitant with a marked decrease in ZO-1 and occludin. Homocysteine-treated HRECs showed increased permeability. CONCLUSIONS: Severe elevation of homocysteine in cbs(-/-) mutant mice is accompanied by alterations in retinal vasculature (ischemia, neovascularization, and incompetent blood-retinal barrier). The marked disruption of retinal structure and decreased visual function reported in cbs(-/-) mice may reflect vasculopathy as well as neuropathy.

Transport of the synthetic opioid peptide DADLE ([D-Ala2,D-Leu5]-enkephalin) in neuronal cells.

The sodium-coupled oligopeptide transporters 1 and 2 (SOPT1 and SOPT2) transport peptides consisting of at least five amino acids and show potential for the delivery of therapeutically relevant peptides/peptidomimetics. Here, we examined the expression of these two transporters in the retinal neuronal cell line RGC-5. These cells showed robust uptake activity for the synthetic pentapeptide DADLE ([D-Ala(2),D-Leu(5)]-Enkephalin). The uptake was Na(+) dependent and saturable (K(t), 6.2 ± 0.6 µM). A variety of oligopeptides inhibited DADLE uptake. The uptake of the competing oligopeptides was directly demonstrated with fluorescein isothiocyanate-labeled Tyr-Gly-Gly-Phe-Leu-Arg-Arg-Ile-Arg-Pro-Lys-Leu-Lys in RGC-5 cells and primary mouse retinal ganglion cells. The characteristics of DADLE uptake matched those of SOPT2. We then examined the expression of SOPT1 in these cells with deltorphin II (Tyr-D-Ala-Phe-Glu-Val-Val-Gly-NH(2)) as the substrate and found that RGC-5 cells also expressed SOPT1. As it is already known that SOPT1 is expressed in the neuronal cell line SK-N-SH, we investigated SOPT2 expression in these cells to determine whether the presence of both oligopeptide transporters is a common feature of neuronal cells. These studies showed that SK-N-SH cells also expressed SOPT2. This constitutes the first report on the functional characterization of SOPT1 and SOPT2 in retinal neuronal cells and on the expression of SOPT2 in nonretinal neuronal cells.

The role of N-methyl-D-aspartate receptor activation in homocysteine-induced death of retinal ganglion cells.

PURPOSE: Elevated plasma homocysteine has been implicated in glaucoma, a vision disorder characterized by retinal ganglion cell death. The toxic potential of homocysteine to ganglion cells is known, but the mechanisms are not clear. A mechanism of homocysteine-induced death of cerebral neurons is via N-methyl-D-aspartate (NMDA) receptor overstimulation, leading to excess calcium influx and oxidative stress. This study examined the role of the NMDA receptor in homocysteine-mediated ganglion cell death. METHODS: Primary mouse ganglion cells were used for these experiments. NMDA receptor stimulation by homocysteine was determined by patch clamp analysis and fluorescent detection of intracellular calcium. NMDA receptor involvement in homocysteine-mediated cell death was determined through assessment of lactate dehydrogenase release and TUNEL analysis. These experiments used the NMDA receptor blocker MK-801. Induction of reactive species superoxide, nitric oxide, and peroxynitrite was measured by electron paramagnetic resonance spectroscopy, chemiluminescent nitric oxide detection, and immunoblotting for nitrotyrosine, respectively. RESULTS: 50 µM homocysteine stimulated the NMDA receptor in presence of 100 µM glycine. Homocysteine induced 59.67 ± 4.89% ganglion cell death that was reduced to 19.87 ± 3.03% with cotreatment of 250 nM MK-801. Homocysteine elevated intracellular calcium ∼7-fold, which was completely prevented by MK-801. Homocysteine treatment increased superoxide and nitric oxide levels by ∼40% and ∼90%, respectively, after 6 hours. Homocysteine treatment elevated peroxynitrite by ∼85% after 9 hours. CONCLUSIONS: These experiments provide compelling evidence that homocysteine induces retinal ganglion cell toxicity through direct NMDA receptor stimulation and implicate, for the first time, the induction of oxidative stress as a potent mechanism of homocysteine-mediated ganglion cell death.