Nitrogen Mustard-Induced Ex Vivo Human Cornea Injury Model and Therapeutic Intervention by Dexamethasone.

Sulfur mustard (SM), a vesicating agent first used during World War I, remains a potent threat as a chemical weapon to cause intentional/accidental chemical emergencies. Eyes are extremely susceptible to SM toxicity. Nitrogen mustard (NM), a bifunctional alkylating agent and potent analog of SM, is used in laboratories to study mustard vesicant-induced ocular toxicity. Previously, we showed that SM-/NM-induced injuries (in vivo and ex vivo rabbit corneas) are reversed upon treatment with dexamethasone (DEX), a US Food and Drug Administration-approved, steroidal anti-inflammatory drug. Here, we optimized NM injuries in ex vivo human corneas and assessed DEX efficacy. For injury optimization, one cornea (randomly selected from paired eyes) was exposed to NM: 100 nmoles for 2 hours or 4 hours, and 200 nmoles for 2 hours, and the other cornea served as a control. Injuries were assessed 24 hours post NM-exposure. NM 100 nmoles exposure for 2 hours was found to cause optimal corneal injury (epithelial thinning [∼69%]; epithelial-stromal separation [6-fold increase]). In protein arrays studies, 24 proteins displayed ≥40% change in their expression in NM exposed corneas compared with controls. DEX administration initiated 2 hours post NM exposure and every 8 hours thereafter until 24 hours post-exposure reversed NM-induced corneal epithelial-stromal separation [2-fold decrease]). Of the 24 proteins dysregulated upon NM exposure, six proteins (delta-like canonical Notch ligand 1, FGFbasic, CD54, CCL7, endostatin, receptor tyrosine-protein kinase erbB-4) associated with angiogenesis, immune/inflammatory responses, and cell differentiation/proliferation, showed significant reversal upon DEX treatment (Student's t test; P ≤ 0.05). Complementing our animal model studies, DEX was shown to mitigate vesicant-induced toxicities in ex vivo human corneas. SIGNIFICANCE STATEMENT: Nitrogen mustard (NM) exposure-induced injuries were optimized in an ex vivo human cornea culture model and studies were carried out at 24 h post 100 nmoles NM exposure. Dexamethasone (DEX) administration (started 2 h post NM exposure and every 8 h thereafter) reversed NM-induced corneal injuries. Molecular mediators of DEX action were associated with angiogenesis, immune/inflammatory responses, and cell differentiation/proliferation, indicating DEX aids wound healing via reversing vesicant-induced neovascularization (delta-like canonical Notch ligand 1 and FGF basic) and leukocyte infiltration (CD54 and CCL7).

Establishing a Dexamethasone Treatment Regimen To Alleviate Sulfur Mustard-Induced Corneal Injuries in a Rabbit Model.

Sulfur mustard (SM) is an ominous chemical warfare agent. Eyes are extremely susceptible to SM toxicity; injuries include inflammation, fibrosis, neovascularization (NV), and vision impairment/blindness, depending on the exposure dosage. Effective countermeasures against ocular SM toxicity remain elusive and are warranted during conflicts/terrorist activities and accidental exposures. We previously determined that dexamethasone (DEX) effectively counters corneal nitrogen mustard toxicity and that the 2-hour postexposure therapeutic window is most beneficial. Here, the efficacy of two DEX dosing frequencies [i.e., every 8 or 12 hours (initiated, as previously established, 2 hours after exposure)] until 28 days after SM exposure was assessed. Furthermore, sustained effects of DEX treatments were observed up to day 56 after SM exposure. Corneal clinical assessments (thickness, opacity, ulceration, and NV) were performed at the day 14, 28, 42, and 56 post-SM exposure time points. Histopathological assessments of corneal injuries (corneal thickness, epithelial degradation, epithelial-stromal separation, inflammatory cell, and blood vessel counts) using H&E staining and molecular assessments (COX-2, MMP-9, VEGF, and SPARC expressions) were performed at days 28, 42, and 56 after SM exposure. Statistical significance was assessed using two-way ANOVA, with Holm-Sidak post hoc pairwise multiple comparisons; significance was established if P < 0.05 (data represented as the mean ± S.E.M.). DEX administration every 8 hours was more potent than every 12 hours in reversing ocular SM injury, with the most pronounced effects observed at days 28 and 42 after SM exposure. These comprehensive results are novel and provide a comprehensive DEX treatment regimen (therapeutic-window and dosing-frequency) for counteracting SM-induced corneal injuries. SIGNIFICANCE STATEMENT: The study aims to establish a dexamethasone (DEX) treatment regimen by comparing the efficacy of DEX administration at 12 versus 8 hours initiated 2 hours after exposure. DEX administration every 8 hours was more effective in reversing sulfur mustard (SM)-induced corneal injuries. SM injury reversal during DEX administration (initial 28 days after exposure) and sustained [further 28 days after cessation of DEX administration (i.e., up to 56 days after exposure)] effects were assessed using clinical, pathophysiological, and molecular biomarkers.

Dexamethasone targets actin cytoskeleton signaling and inflammatory mediators to reverse sulfur mustard-induced toxicity in rabbit corneas.

PURPOSE: Sulfur mustard (SM), a bi-functional alkylating agent, was used during World War I and the Iran-Iraq war. SM toxicity is ten times higher in eyes than in other tissues. Cornea is exceptionally susceptible to SM-injuries due to its anterior positioning and mucous-aqueous interphase. Ocular SM exposure induces blepharitis, photosensitivity, dry eye, epithelial defects, limbal ischemia and stem cell deficiency, and mustard gas keratopathy leading to temporary or permanent vision impairments. We demonstrated that dexamethasone (Dex) is a potent therapeutic intervention against SM-induced corneal injuries; however, its mechanism of action is not well known. Investigations employing proteomic profiling (LC-MS/MS) to understand molecular mechanisms behind SM-induced corneal injury and Dex efficacy were performed in the rabbit cornea exposed to SM and then received Dex treatment. PEAKS studio was used to extract, search, and summarize peptide identity. Ingenuity Pathway Analysis was used for pathway identification. Validation was performed using immunofluorescence. One-Way ANOVA (FDR < 0.05; p < 0.005) and Student's t-test (p < 0.05) were utilized for analyzing proteomics and IF data, respectively. Proteomic analysis revealed that SM-exposure upregulated tissue repair pathways, particularly actin cytoskeleton signaling and inflammation. Prominently dysregulated proteins included lipocalin2, coronin1A, actin-related protein2, actin-related protein2/3 complex subunit2, actin-related protein2/3 complex subunit4, cell division cycle42, ezrin, bradykinin/kininogen1, moesin, and profilin. Upregulated actin cytoskeleton signaling increases F-actin formation, dysregulating cell shape and motility. Dex reversed SM-induced increases in the aforementioned proteins levels to near control expression profiles. Dex aids corneal wound healing and improves corneal integrity via actin cytoskeletal signaling and anti-inflammatory effects following SM-induced injuries.

Refractive outcomes using Barrett formulas and patient characteristics of cataract surgery patients with and without prior LASIK/PRK.

PURPOSE: The goal of this study is to describe characteristics of cataract surgery patients who previously underwent laser in situ keratomileusis/photorefractive keratectomy (LASIK/PRK) in comparison to non-LASIK/PRK cataract surgery patients including psychiatric comorbidities, as well as describe refractive prediction error after cataract surgery while accounting for axial length (AL) using the Barrett True-K and Barrett Universal II formulas. METHODS: This was a retrospective study of patients from the University of Colorado Cataract Outcomes Registry. The primary outcomes were refraction prediction error (RPE), mean absolute RPE, and median absolute RPE. Outcomes were stratified by five axial length groups. Univariate and multivariate models for RPE were stratified by the AL group. RESULTS: Two hundred eighty-one eyes with prior LASIK/PRK and 3101 eyes without are included in the study. Patients with prior LASIK/PRK were significantly younger: 67.0 vs 69.9 years, p < 0.0001. The LASIK/PRK group had significantly better mean pre-operative BCVA in comparison to the non-LASIK group, logMAR 0.204 vs logMAR 0.288, p = 0.003. The LASIK/PRK group had significantly lower rates of cardiovascular disease (18.5% vs 29.3%, p < 0.001), hypertension (49.1% vs 59.3%, p < 0.012), and type 2 diabetes (10.7% vs 26.0%, p < 0.001), and no significant difference in psychiatric disease. The absolute RPE was higher for the LASIK group for all ALs, but only significantly higher for eyes with AL less than 25 mm. CONCLUSION: Patient eyes with prior LASIK/PRK surgery undergoing cataract surgery were significantly younger, had significantly less comorbidities, and a significantly better pre-operative BCVA. Using the Barrett formulas, absolute prediction error for eyes with longer ALs was not significantly worse for LASIK/PRK eyes than those without and the difference was smaller for eyes with longer AL.

Transforming growth factor-ß2-mediated mesenchymal transition in lens epithelial cells is repressed in the absence of RAGE.

Transforming growth factor-ß2 (TGFß2)-mediated epithelial to mesenchymal transition (EMT) in lens epithelial cells (LECs) has been implicated in fibrosis associated with secondary cataracts. In this study, we investigated whether the receptor for advanced glycation end products (RAGE) plays a role in TGFß2-mediated EMT in LECs. Unlike in the LECs from wild-type mice, TGFß2 failed to elicit an EMT response in LECs from RAGE knockout mice. The lack of RAGE also diminished TGFß2-mediated Smad signaling. In addition, treatment with TGFß2 increased IL-6 levels in LECs from wild-type mice but not in those from RAGE knockout mice. Treatment of human LECs with the RAGE inhibitor FPS-ZM1 reduced TGFß2-mediated Smad signaling and the EMT response. Unlike that in wild-type lenses, the removal of fiber cell tissue in RAGE knockout lenses did not result in elevated levels of α-smooth muscle actin (α-SMA), fibronectin (FN), and integrin ß1 in capsule-adherent LECs. Taken together, these results suggest that TGFß2 signaling is intricately linked to RAGE. Targeting RAGE could be explored as a therapeutic strategy against secondary cataracts.

Aspirin inhibits TGFß2-induced epithelial to mesenchymal transition of lens epithelial cells: selective acetylation of K56 and K122 in histone H3.

Posterior capsule opacification (PCO) is a complication after cataract surgery that can disrupt vision. The epithelial to mesenchymal transition (EMT) of lens epithelial cells (LECs) in response to transforming growth factor ß2 (TGFß2) has been considered an obligatory mechanism for PCO. In this study, we tested the efficacy of aspirin in inhibiting the TGFß2-mediated EMT of human LECs, LECs in human lens capsular bags, and lensectomized mice. In human LECs, the levels of the EMT markers α-smooth muscle actin (α-SMA) and fibronectin were drastically reduced by treatment with 2 mM aspirin. Aspirin also halted the EMT response of TGFß2 when introduced after EMT initiation. In human capsular bags, treatment with 2 mM aspirin significantly suppressed posterior capsule wrinkling and the expression α-SMA in capsule-adherent LECs. The inhibition of TGFß2-mediated EMT in human LECs was not dependent on Smad phosphorylation or MAPK and AKT-mediated signaling. We found that aspirin significantly increased the acetylation of K56 and K122 in histone H3 of human LECs. Chromatin immunoprecipitation assays using acetyl-H3K56 or acetyl-H3K122 antibody revealed that aspirin blocked the TGFß2-induced acetylation of H3K56 and H3K122 at the promoter regions of ACTA2 and COL1A1. After lensectomy in mice, we observed an increase in the proliferation and α-SMA expression of the capsule-adherent LECs, which was ameliorated by aspirin administration through drinking water. Taken together, our results showed that aspirin inhibits TGFß2-mediated EMT of LECs, possibly from epigenetic down-regulation of EMT-related genes.

Human trabecular meshwork cell behavior is influenced by collagen scaffold pore architecture and glycosaminoglycan composition.

Glaucoma is a degenerative eye disease in which damage to the optic nerve leads to a characteristic loss of vision. The primary risk factor for glaucoma is an increased intraocular pressure that is caused by an imbalance of aqueous humor generation and subsequent drainage through the trabecular meshwork (TM) drainage system. The small size, donor tissue limitations, and high complexity of the TM make it difficult to research the relationship between the TM cells and their immediate environment. Thus, a biomaterial-based approach may be more appropriate for research manipulations and in vitro drug development platforms. In this work, human TM (hTM) cells were cultured on various collagen scaffolds containing different glycosaminoglycans (GAGs) and different pore architectures to better understand how hTM cells respond to changes in their extracellular environment. Cellular response was measured by quantifying cellular proliferation and expression of an important extracellular matrix protein, fibronectin. The pore architecture of the scaffolds was altered using freeze-casting technique to make both large and small pores that were aligned or with a non-aligned random structure. The composition of the scaffolds was altered with the addition of chondroitin sulfate and/or hyaluronic acid. It was found that the hTM cells grown on large pore scaffolds proliferate more than those grown on small pores. There was an increase in the fibronectin expression with the incorporation of GAGs, and its morphology was changed by the underlying pore architecture. This work will help provide an insight into the behavior of hTM cells when introducing changes in their microenvironment.

Kynurenic Acid Protects Against Ischemia/Reperfusion-Induced Retinal Ganglion Cell Death in Mice.

BACKGROUND: Glaucoma is an optic neuropathy and involves the progressive degeneration of retinal ganglion cells (RGCs), which leads to blindness in patients. We investigated the role of the neuroprotective kynurenic acid (KYNA) in RGC death against retinal ischemia/reperfusion (I/R) injury. METHODS: We injected KYNA intravenously or intravitreally to mice. We generated a knockout mouse strain of kynurenine 3-monooxygenase (KMO), an enzyme in the kynurenine pathway that produces neurotoxic 3-hydroxykynurenine. To test the effect of mild hyperglycemia on RGC protection, we used streptozotocin (STZ) induced diabetic mice. Retinal I/R injury was induced by increasing intraocular pressure for 60 min followed by reperfusion and RGC numbers were counted in the retinal flat mounts. RESULTS: Intravenous or intravitreal administration of KYNA protected RGCs against I/R injury. The I/R injury caused a greater loss of RGCs in wild type than in KMO knockout mice. KMO knockout mice had mildly higher levels of fasting blood glucose than wild type mice. Diabetic mice showed significantly lower loss of RGCs when compared with non-diabetic mice subjected to I/R injury. CONCLUSION: Together, our study suggests that the absence of KMO protects RGCs against I/R injury, through mechanisms that likely involve higher levels of KYNA and glucose.

Collagen and collagen-chondroitin sulfate scaffolds with uniaxially aligned pores for the biomimetic, three dimensional culture of trabecular meshwork cells.

Glaucoma is a disease in which damage to the optic nerve leads to progressive, irreversible vision loss. The intraocular pressure (IOP) is the only modifiable risk factor for glaucoma and its lowering is considered a useful strategy for preventing or slowing down the progression of glaucomatous neuropathy. Elevated intraocular pressure associated with glaucoma is due to increased aqueous humor outflow resistance, primarily through the trabecular meshwork (TM) of the eye. Current in vitro models of the trabecular meshwork are oversimplified and do not capture the organized and complex three-dimensional nature of this tissue that consists primarily of collagen and glycoasaminoglycans. In this work, collagen and collagen-chondroitin sulfate (CS) scaffolds were fabricated via unidirectional freezing and lyophilization to induce the formation of aligned pores. Scaffolds were characterized by scanning electron microscopy, dynamic mechanical analysis, and a chondroitin sulfate quantification assay. Scaffold characterization confirmed the formation of aligned pores, and also that the CS was leaching out of the scaffolds over time. Primary porcine trabecular meshwork (TM) cells were seeded onto the surface of scaffolds and their gene expression, proliferation, viability, migration into the scaffolds, and morphology were examined. The TM cells were viable and proliferated 2 weeks after seeding. The cells migrated down into the internal scaffold structure and their morphology reflected the topography and alignment of the scaffold structure. This work is a promising step toward the development of a three dimensional in vitro model of the TM that can be used for testing of glaucoma pharmacological agents in future experimentation and to better our understanding of the trabecular meshwork and its complex physiology. Biotechnol. Bioeng. 2017;114: 915-923. © 2016 Wiley Periodicals, Inc.

αB-crystallin is essential for the TGF-ß2-mediated epithelial to mesenchymal transition of lens epithelial cells.

Transforming growth factor (TGF)-ß2-mediated pathways play a major role in the epithelial to mesenchymal transition (EMT) of lens epithelial cells (LECs) during secondary cataract formation, which is also known as posterior capsule opacification (PCO). Although αB-crystallin is a major protein in LEC, its role in the EMT remains unknown. In a human LEC line (FHL124), TGF-ß2 treatment resulted in changes in the EMT-associated proteins at the mRNA and protein levels. This was associated with nuclear localization of αB-crystallin, phosphorylated Smad2 (pSmad2) (S245/250/255), pSmad3 (S423/425), Smad4 and Snail and the binding of αB-crystallin to these transcription factors, all of which were reduced by the down-regulation of αB-crystallin. Expression of the functionally defective R120G mutant of αB-crystallin reduced TGF-ß2-induced EMT in LECs of αB-crystallin knockout (KO) mice. Treatment of bovine lens epithelial explants and mouse LEC with TGF-ß2 resulted in changes in the EMT-associated proteins at the mRNA and protein levels. This was accompanied by increase in phosphorylation of p44/42 mitogen-activated protein kinases (MAPK) (T202/Y204), p38 MAPK (T180/Y182), protein kinase B (Akt) (S473) and Smad2 when compared with untreated cells. These changes were significantly reduced in αB-crystallin depleted or knocked out LEC. The removal of the fibre cell mass from the lens of wild-type (WT) mice resulted in the up-regulation of EMT-associated genes in the capsule-adherent epithelial cells, which was reduced in the αB-crystallin KO mice. Together, our data show that αB-crystallin plays a central role in the TGF-ß2-induced EMT of LEC. αB-Crystallin could be targeted to prevent PCO and pathological fibrosis in other tissues.

Aflibercept for the treatment of neovascular glaucoma.

BACKGROUND: Neovascular glaucoma (NVG) is a potentially blinding disease associated with ocular ischaemia. Use of an anti-vascular endothelial growth factor agent has been reported as a treatment option for NVG. The purpose of this study was to investigate initial results regarding the treatment of NVG with intravitreal aflibercept. DESIGN: This study employed a prospective, interventional case series study design. PARTICIPANTS: Patients with newly diagnosed stage 1 or 2 neovascular glaucoma were eligible to participate in this study. METHODS: Four patients with newly diagnosed stage 1 or 2 NVG were treated with intravitreal aflibercept at the time of diagnosis, with planned repeat injection at 4 weeks, 8 weeks and then every 8 weeks thereafter up until 52 weeks after study initiation. MAIN OUTCOME MEASURES: Primary outcomes were regression of neovascularization of the iris and angle (NVI, NVA). Secondary outcome measurements included visual acuity and intraocular pressure (IOP). RESULTS: Intravitreal aflibercept resulted in rapid regression of NVI and NVA. IOP was stable or reduced in all patients at the 52-week study visit. CONCLUSIONS: These results suggest that intravitreal aflibercept may be an effective treatment for stage 1 and 2 NVG, resulting in rapid and sustained regression of NVI and NVA as well as control of IOP. Further research is needed to determine the full duration of effect and the optimal dose and timing of administration.

Outcomes of Micropulse Transscleral Cyclophotocoagulation in Uveitic Glaucoma.

PURPOSE: To report a case series of patients with uveitic glaucoma who were treated with micropulse transscleral cyclophotocoagulation (mpCPC). METHODS: This retrospective case series consists of patients from the University of Colorado Sue Anschutz-Rodgers Eye Center from 2015 to 2020 who were diagnosed with uveitic glaucoma. Information collected includes demographic data, type of uveitis, glaucoma severity, and prior glaucoma surgeries. Pre- and postoperative best corrected visual acuity, intraocular pressure (IOP), glaucoma medications, degree of inflammation, and uveitis therapies were included up to 36 months postoperatively. Surgical success was defined as an IOP reduction of 30% with achievement of IOP goal using the same number of glaucoma medications or less at 6 months or 1 year. Uveitis success was defined as the absence of persistent anterior uveitis at 3 months. RESULTS: Six patients and seven eyes with uveitic glaucoma underwent mpCPC. Types of uveitis included idiopathic anterior uveitis, HLA-B27-associated anterior uveitis, varicella zoster virus anterior uveitis, juvenile idiopathic arthritis-associated chronic anterior uveitis, lichen planus-associated intermediate uveitis, and sarcoidosis-associated panuveitis. Two of six eyes (33.3%) at 6 months and three of five eyes (60%) at 1 year achieved surgical success. Around 6 months postoperatively, two out of seven eyes (28.6%) required Ahmed glaucoma valve placement (n = 1) or repeat mpCPC (n = 1). One eye (14.3%) required phacoemulsification with goniotomy followed by an Ahmed glaucoma valve 18 months after mpCPC. There were no cases of persistent anterior uveitis, hypotony, or phthisis after mpCPC in this cohort. CONCLUSIONS: Micropulse transscleral cyclophotocoagulation may safely reduce intraocular pressure in some patients with uveitic glaucoma without exacerbation of intraocular inflammation. Multiple treatments may be required to achieve longer-term success.

Outcomes and Risk Factors for Complications in Cataract Patients with Hepatitis C Virus Infection.

PURPOSE: To describe outcomes of patients with hepatitis C virus (HCV) seropositivity undergoing cataract surgery, as well as investigate risk factors for surgical complications. METHODS: This is a retrospective cohort study of all consecutive patients who underwent cataract surgery at a tertiary care hospital in the United States between 2014 and 2019. The exposure of interest was HCV seropositivity and outcomes included surgical complications and associated risk factors, visual acuity, and post-operative complications. RESULTS: A total of 11,276 eyes of 6,858 patients were included in the study, of which 122 patients (1.78%) and 210 eyes (1.86%) were HCV positive. Average age at surgery was 63.4 (8.4) years for HCV positive patients and 69.1 (10.6) years for HCV negative patients. Patients with HCV were more likely to suffer a complication during cataract surgery, 2.9% versus 1.2% (OR 2.27, 95% CI 1.03 to 5.01, p = .0415). Postoperative best corrected visual acuity was excellent: median and range 0.00 (-0.13, 3.00) logMAR for HCV positive eyes versus 0.00 (-0.30, 3.00) logMAR for HCV negative eyes. Among HCV positive patients, elevated alanine transaminase (>52 U/L) was associated with a higher intraoperative complication rate (10.0% vs 1.8%, OR 5.53, 95% CI 1.05 to 29.2, p = .044). CONCLUSION: While patients with HCV are more likely to have complications during cataract surgery, final best corrected visual acuity was excellent regardless of HCV status. Patients with HCV are more likely to undergo cataract surgery at a younger age, and those with elevated alanine transaminase are at highest risk for complications.

Comparison of Outcomes of Phacoemulsification Combined with Endoscopic Cyclophotocoagulation, iStent, or Both in the Management of Open-Angle Glaucoma.

INTRODUCTION: To compare outcomes of phacoemulsification combined with endoscopic cyclophotocoagulation (phaco/ECP), first generation iStent implantation (phaco/iStent), or both (phaco/iStent/ECP) in patients with open-angle glaucoma. METHODS: A retrospective chart review was performed on patients at the University of Colorado Department of Ophthalmology. Outcomes included intraocular pressure (IOP), medication use, best corrected visual acuity (BCVA), and surgical complications were analyzed. Success was defined as IOP reduction of ≥ 20% and/or reduction by at least one glaucoma medication. RESULTS: A total of 394 eyes were included in the study. There were 170 eyes (43.1%) in the phaco/ECP group, 175 eyes (44.4%) in the phaco/iStent group, and 49 eyes (12.4%) in the phaco/iStent/ECP group. The mean pre-operative IOP was 15.9 mmHg for phaco/ECP, 15.8 mmHg for phaco/iStent, and 15.2 mmHg for phaco/iStent/ECP. At 24 months, the mean IOP was 13.7 mmHg (p < 0.0001), 14.2 mmHg (p = 0.0001), and 13.0 mmHg (p = 0.0007), respectively. The mean pre-operative number of glaucoma medications was 2.0 for phaco/ECP, 1.4 for phaco/iStent, and 2.2 for phaco/iStent/ECP and at 24 months post-surgery decreased to, 1.8 (p = 0.011), 0.9 (p < 0.0001), and 1.7 (p = 0.01), respectively. The success rate at 24 months was 54.4% for phaco/ECP, 75.3% for phaco/iStent, and 55.6% for phaco/iStent/ECP. CONCLUSION: Phacoemulsification when combined with ECP, iStent, or both, lowered IOP and glaucoma medication reliance at 24 months. The success rate for phaco/iStent was significantly higher than phaco/ECP. When iStent was added to phaco/ECP, the success rate was higher at earlier postoperative visits compared to the phaco/ECP alone.

Subjective and Objective Measurement of Sleep Quality and Activity in Glaucoma.

PRCIS: Glaucoma patients exhibit worse indices of sleep function by both objective and subjective metrics compared with controls. PURPOSE: The purpose of this study is to characterize the sleep parameters and physical activity levels of glaucoma patients compared with controls. PATIENTS AND METHODS: A total of 102 patients with a diagnosis of glaucoma in at least 1 eye and 31 control subjects were enrolled in the study. Participants completed the Pittsburgh Sleep Quality Index (PSQI) during enrollment and then wore wrist actigraphs for 7 consecutive days to characterize circadian rhythm, sleep quality, and physical activity. The primary outcomes of the study were subjective and objective metrics of sleep quality using the PSQI and actigraphy devices, respectively. The secondary outcome was physical activity, measured by the actigraphy device. RESULTS: From the PSQI survey, glaucoma patients had higher (worse) scores compared with controls for sleep latency, sleep duration, and subjective sleep quality, whereas scores for sleep efficiency were lower (better), suggesting more time spent in bed asleep. By actigraphy, time in bed was significantly higher in glaucoma patients as was time awake after sleep onset. Interdaily stability, quantifying the synchronization to the 24-hour light-dark cycle, was lower in glaucoma patients. There were no other significant differences between glaucoma and control patients with regard to rest-activity rhythms or physical activity metrics. In contrast to the survey data, findings from the actigraphy demonstrated that there were no significant associations between the study group and controls regarding sleep efficiency, onset latency, or total sleep time. CONCLUSIONS: In this study, patients with glaucoma demonstrated several subjective and objective differences in sleep function when compared with controls, whereas physical activity metrics were similar.

Glycosaminoglycans Influence Extracellular Matrix of Human Trabecular Meshwork Cells Cultured on 3D Scaffolds.

Glaucoma is a multifactorial progressive optic neuropathy characterized by the loss of retinal ganglion cells leading to irreversible blindness. It is the leading cause of global irreversible blindness and is currently affecting over 70 million people. Elevated intraocular pressure (IOP) is considered the only modifiable risk factor and is a target of numerous treatment modalities. Researchers have assigned this elevation of IOP to accumulation of extracellular matrix (ECM) components in the aqueous humor (AH) outflow pathway. The major drainage structure for AH outflow is the trabecular meshwork (TM). The ECM of the TM is important in regulating IOP in both normal and glaucomatous eyes. In this work, we have studied the role of exogeneous glycosaminoglycans (GAGs), glucocorticoids, and culture conditions on the expression of the ECM gene and proteins by human TM (hTM) cells cultured on biomaterial scaffolds. Gene and protein expression levels of elastin, laminin, and matrix metalloproteinase-2 (MMP-2) were evaluated using quantitative PCR and immunohistochemistry. Pressure gradient changes in cell-laden scaffolds in perfusion cultures were also monitored. Our findings show that GAGs and dexamethasone play an influencing role in hTM ECM turnover at both transcriptional and translational levels by altering expression levels of elastin, laminin, and MMP-2. Understanding the role of exogeneous factors on hTM cell behavior is helpful in gaining insights on glaucoma pathogenesis and ultimately pivotal in development of novel therapeutics against the disease.

Iris Retraction Without Hypotony.

PURPOSE: All published cases of iris retraction syndrome have been associated with low intraocular pressure. We report here a case clinically indistinguishable from iris retraction syndrome except for the absence of hypotony, which has not been previously described in the literature. OBSERVATIONS: A 35-year-old woman with a history of atopic dermatitis developed a rapidly progressive anterior subcapsular cataract and acute uveitis. During follow-up, the presence of bilateral iris retraction was noted, while ocular pressure was either normal or elevated, and the position did not normalize with pupillary dilation. The clinical course was complicated by retinal detachment and posterior cyclitic membrane, which was managed with pars plana vitrectomy, lensectomy, and dissection of cyclitic membrane. The case was further complicated by ocular hypertension attributed to steroid response and formation of an epiretinal membrane. Following micropulse cyclophotocoagulation, placement of an Ahmed tube shunt, epiretinal membrane peel, and placement of secondary intraocular lens, our patient eventually had a good visual outcome. CONCLUSIONS AND IMPORTANCE: Hypotony is generally recognized as a key physiological step in the development of iris retraction syndrome. Our case demonstrates that posterior bowing of the iris can occur in the absence of hypotony, and suggests that an alternative mechanism involving posterior cyclitic membrane may be responsible.

Hydrus Microstent malposition with uveitis-glaucoma-hyphema syndrome.

Intraocular implants, specifically those used in the treatment of glaucoma, are each associated with various implant related risks and complications of which surgeons placing these devices must be aware. Here we present a case of uveitis-glaucoma-hyphema (UGH) syndrome associated with the Hydrus Microstent.

AAV2-Mediated Expression of HspB1 in RGCs Prevents Somal Damage and Axonal Transport Deficits in a Mouse Model of Ocular Hypertension.

Purpose: Ocular hypertension is a significant risk factor for vision loss in glaucoma caused by the death of retinal ganglion cells (RGCs). We investigated whether small heat shock proteins (sHsps) expressed in RGCs protect those cells against ocular hypertension in mice. Methods: AAV2 vectors encoding genes for one of the following four human sHsps: HSPB1, HSPB4, HSPB5, or HSPB6 were constructed for RGC-specific expression. Ischemia/reperfusion was induced by elevating the intraocular pressure (IOP) to 120 mm Hg for one hour, followed by a rapid return to normal IOP. Microbeads (MB) were injected into the anterior chamber of mice to induce ocular hypertension. RGC death and glial activation were assessed by immunostaining for Brn3a, RBPMS, Iba1, and glial fibrillary acid protein in retinal flat mounts. RGC axonal defects were evaluated by anterograde transport of intravitreally injected cholera toxin-B. RGC function was assessed by pattern electroretinography. Results: Among the sHsps, HspB1 offered the best protection against RGC death from ischemia/reperfusion injury in the mouse retina. Intravitreal administration of AAV2-HSPB1 either two weeks before or one week after instituting ocular hypertension resulted in significant prevention of RGC loss. The MB-injected mice showed RGC axonal transportation defects, but AAV2-HSPB1 administration significantly inhibited this defect. AAV2-HSPB1 prevented glial activation caused by ocular hypertension. More importantly, a single injection of AAV2-HSPB1 protected RGCs long-term in MB-injected eyes. Conclusions: The administration of AAV2-HSPB1 inhibited RGC death and axonal transport defects and reduced glial activation in a mouse model of ocular hypertension. Translational Relevance: Our results suggested that the intravitreal delivery of AAV2-HSPB1 could be developed as a gene therapy to prevent vision loss on a long-term basis in glaucoma patients.