Eye / Vision

Permanent URI for this collectionhttps://hdl.handle.net/20.500.12503/21654


Recent Submissions

Now showing 1 - 10 of 10
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    Are Smokers More Likely to be Non-Compliant with their Medications? An Examination of Permanent Supportive Housing (PSH) Residents in Fort Worth, Texas
    (2018-03-14) Walters, Scott; Moore, Jonathan; Moore, Jonathan
    Purpose: People with a history of chronic homelessness are disproportionately more likely to smoke and have problems with medication compliance. Moreover, smoking and medication adherence are often related; people who smoke tend to have more trouble taking their medications. However, no studies to our knowledge have investigated this relationship among a group of formerly homeless individuals who have mental health symptoms. The current study utilized a sample of permanent supportive housing (PSH) residents in Ft. Worth, TX who were participating in a health coaching program. It was hypothesized that people who smoked would have more difficulties adhering to their medication regimens. Methods: Data were from m.chat, a technology-enhanced health coaching program for PSH residents with mental health symptoms. Data from November 2014 - March 2017, which consisted of 567 participants, were included. Baseline smoking status was determined by the following question: do you currently smoke cigarettes, or use other forms of tobacco? (yes vs. no). Medication adherence was identified using a modified Morisky Medication Adherence Scale, which categorized people as low vs. medium/high adherence. Covariates were selected based on prior literature and the information available in our data. Logistic regression was used for the analysis. Results: Medication adherence was similar between smokers and non-smokers (aOR: 0.78, 95% CI: 0.41, 1.49). However, drug abuse was significantly associated with medication adherence; people who reported consuming any illicit drug or abusing a prescription medication in the past 90 days had 73% lower odds (aOR: 0.27, 95% CI: 0.12, 0.65) of adhering to medications compared to those who reported no drug abuse. Alcohol consumption was significant in the unadjusted analysis, but was not significant after adjusting for other factors. Conclusions: Among a group of PSH residents with a history of homelessness, smokers and non-smokers had similar rates of medication adherence. Although smoking was not associated with medication adherence, other forms of substance use were related to a poorer medication adherence. This research highlights the role of illicit drug use in predicting medication adherence; programs that attempt to improve rates of medication adherence should take drug use into account as a key predictor of compliance.
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    A Mechanism study toward understanding the protective effects of glutaredoxin 2 (Grx2) on light-induced retinal damage
    (2018-03-14) Liu, Xiaobin; Xavier, Christy; Ananti, Princess; Liu, Yang; Wu, Hongli; Wang, Duen-Shian
    Purpose: Glutaredoxin 2 (Grx2), located mainly in the mitochondria, is a glutathione-dependent oxidoreductase which is known to reduce S-glutathionylated proteins. In previous study, we have found that Grx2 could protect the retina from light-induced retinal degeneration. However, the molecular mechanisms that coordinate mitochondrial energy production with thiol-repair processes in the damaged retina remain largely unknown. To better understand the protective effects of Grx2 in the retina, our study was thus extended to analyze the full transcriptome changes of the retinal tissue in light-exposed Grx2 knockout (KO) mice. Methods: Wild type (WT) and Grx2 KO mice were exposed to white light at 12,000 lux for 1 hour after dark adaptation. The retinal damage was confirmed by the electroretinogram (ERG) recording and spectral domain optical coherence tomography (SD-OCT) measurement. Protein glutathionylation level was evaluated by Western Blot. We then compared the full transcriptome of the retinal tissue in WT and Grx2 KO mice by performed the whole transcriptome shotgun sequencing (RNA-seq). The gene network was analyzed using DESeq2 pathway analysis software and the selected genes of interest were further confirmed by real-time PCR and Western Blot. Results: Light-exposed Grx2 KO mice showed compromised visual function as indicated by severe loss of both a- and b-wave amplitudes and the thinning of the outer nuclear layer (ONL). Protein glutathionylation level was elevated in light-exposed Grx2 KO mice. We identified thousands of genes with statistical significant expression changes in light-exposed Grx2 KO mice and classified them into cellular processes and molecular pathways. Among these pathways, many genes that are related to complement activation and inflammation reaction were significantly upregulated. These genes include complement C3, C4a, C4B (C4B), Bcl-3, NF-kappa B, Jak3, and STAT3. Conclusions: Collectively, our results suggest that Grx2 could protect the retina from light-induced retinal degeneration. It plays an important role in regulating light-induced retinal inflammation which may be associated with its ability to reduce S-glutathionylated substrates.
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    Discovery of new agents to inhibit scarring and improve the success of glaucoma surgery
    (2018-03-14) McDowell, Colleen; Hoelscher, Callie
    Purpose: Glaucoma is a common ophthalmological condition related to elevated intraocular pressure (IOP). Glaucoma can sometimes be treated surgically with a procedure called a trabeculectomy that allows for increased drainage of the aqueous humor of the eye to reduce the IOP. After this surgery, many patients develop a scar at the surgical site that can reverse the benefits of the surgery. This study aims to compare multiple inhibitors of the TGFβ2-TLR4 signaling pathway against the current standard treatment for scar inhibition to determine if they could be more effective. Less scarring would lead to better maintainence of lower IOP and more successful glaucoma surgeries. Methods: Primary human conjunctiva/tenon fibroblast cell strains were treated with Mitomycin C (MMC), the standard treatment to prevent scarring, TAK-242 (a selective inhibitor of TLR4), or NBP2-29328 (a selective inhibitor of MyD88). NBP2-29328, TAK-242, and untreated cells were incubated with 0.5% FBS for 24 hours, and MMC cells were incubated for 5 minutes. Next, a wound scratch assay was performed. Each well was photographed with a Keyence imager at 0, 6, 24, 48, 72, and 96 hours post-scratch. Using ImageJ software, the 0-hour images were analyzed to get an area value and a ROI (Region of Interest) outline of the 0-hour scratch. The later images were analyzed to get values for the number of cells present and their total area covered. The four treatments were compared for efficacy of inhibition of cell migration and proliferation. This protocol has been performed in two studies. Results: There were significant differences between treatments at 72 and 96 hours. In the first study, inhibition from the MMC treatment was significant compared to control (p Conclusions: The data from the studies suggest that these treatments may be useful for scar inhibition after glaucoma trabeculectomy surgery.
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    Inhibition of chronic endoplasmic reticulum stress rescues myocilin-associated glaucoma via stimulation of autophagic flux in the TM
    (2018-03-14) Maddineni, Prabhavathi; Patel, Pinkal; Zode, Gulab; Kasetti, Ramesh
    Purpose: We have previously demonstrated that expression of mutant myocilin leads to chronic ER-stress induced transcriptional factors such as ATF4 and CHOP, which may lead to TM dysfunction and IOP elevation. Here, we explored whether and how genetic knockdown of ATF4 or CHOP rescues myocilin-associated glaucoma Methods: Autophagic flux was monitored in Tg-MYOCY437H mice and primary human TM cells using adenoviral expression of RFP-GFP-LC3 and analysis of key autophagy markers LC3B and P62. Key mediators of chronic ER stress, ATF4 or CHOP were knocked down using CRISPR-Cas9. Myocilin accumulation and autophagic flux was examined in TM cells and Tg-MYOCY437H mice. We further examined whether stimulation of autophagy via TatBeclin 1 peptide or Torin 2 on glaucoma phenotype and mutant myocilin accumulation using mice and TM cells Results: Expression of mutant myocilin impaired autophagic flux in primary TM cells and in the TM of Tg-MYOC Y437H mice as evident from increased LC3BI/II ratio, p62 and decreased red/yellow puncta of RFP-GFP-LC3B constructs. CRISPR-Cas9 mediated ATF4 or CHOP knockdown in TM cells stably expressing mutant myocilin improved autophagic mediated degradation of mutant myocilin, as evident by an increased LC3II/LC3I ratio, decreased P62, decreased mutant myocilin accumulation. Increased colocalization of LC3 with mutant myocilin in lysosomes was observed in ATF4 or CHOP deleted TM cells demonstrating active autophagic degradation of mutant myocilin. A dose dependent decrease in mutant myocilin accumulation was observed upon Tat-Beclin 1 treatment of TM cells expressing mutant myocilin. Tat-Beclin 1 or Torin 2 (autophagy inducers) treatment reduced intraocular pressure in Tg-MYOCY437H mice. Moreover, Western blot analysis of mice anterior segment lysates demonstrated induction of autophagy markers and reduction of mutant myocilin accumulation Conclusions: Genetic knockdown of ATF4 or CHOP increased autophagy flux, and facilitated autophagy-mediated clearance of accumulated mutant myocilin. Moreover, chemical induction of autophagy reduced mutant myocilin and rescued glaucoma in mice further suggesting the feasibility of targeting autophagy for the treatment of glaucoma
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    TRPV4-mediated regulation of intraocular pressure and outflow facility in mouse model of glucocorticoid-induced ocular hypertension
    (2018-03-14) Millar, Cameron; Kasetti, Ramesh; Maddineni, Prabhavathi; Zode, Gulab; Patel, Pinkal
    Purpose: Increased intraocular pressure (IOP) due to increased outflow resistance to aqueous humor at the trabecular meshwork (TM) is one of the major risk factor associated with glaucoma. Transient receptor potential channel vanilloid isoform 4 (TRPV4), a polymodal cation-permeable channel, has been implicated in mechanotransduction. Increased IOP and reduced outflow of aqueous humor may compromise the mechanosensory signaling in the trabecular meshwork. We hypothesize a dysfunction in the mechanotransduction pathway in the TM of hypertensive eyes, and propose a physiological role for TRPV4 channels in regulation of IOP and outflow facility. Methods: The effects of TRPV4 activation was studied using recently developed mouse model of glucocorticoid-induced ocular hypertension. 20 mL of 10 mg/mL dexamethasone-21-acetate (Dex-Ac) formulation was administered weekly to both eyes of C57BL/6J mice via periocular conjunctival fornix injections. Ocular hypertensive mice were topically administered 1 mM GSK1016790A (TRPV4 agonist) in one eye and DMSO vehicle in the contralateral eye. The subsequent effect on IOP was recorded 15, 30, and 60 min intervals after the eye drops and weekly in isoflurane anesthetized mice. Outflow facility was further examined in ocular hypertensive mice treated with 1 mM GSK1016790A eye drops 1 hour prior to the measurements. Results: Weekly periocular injections of Dex-Ac showed significant increase in IOP greater than 5 mmHg, when compared to vehicle control (P. In ocular hypertensive mice, topical administration of TRPV4 activator caused significant and sustained decrease in IOP back to baseline levels, when compared to vehicle treated contralateral eyes (P. IOP measurement at different time points following TRPV4 activation showed a rapid effect on IOP within 60 minutes (P. Measurement of outflow facility via the constant-flow infusion method shows a significant increase in outflow facility one hour after topical administration of TRPV4 agonist when compared to the vehicle treated contralateral eyes (P=0.026). Conclusion: Our data provides physiological evidence for the positive effect of TRPV4 activation on IOP and outflow facility. Further work is required to elucidate the underlying molecular mechanisms behind TRPV4-mediated effect on IOP and outflow facility.
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    Using Grapes as a Magic Bullet to Fight Against Free Radicals in the Eye: Application for Cataract Prevention
    (2018-03-14) Xavier, Christy; Wang, Duen-Shian; Ananti, Princess; Liu, Yang; Wu, Hongli; Liu, Xiaobin
    Purpose: The main purpose of this study is to investigate if grape powder could protect against in vivo ultraviolet (UV) radiation-induced cataract and to study its mechanism of action and identify its targets in the lens. Methods: The grape powder was provided by the California Table Grape Commission (CTGC). C57BL/6J mice were feed with the regular diet, regular diet supplemented with glucose and fructose, or the grape diet (regular diet supplemented with 5%, 10%, and 15% grape powder) for 3 months. The animals were then exposed to 20.6 kJ/m2 UV radiation for 15 min to induce cataracts. Two days later, the degree of the cataract and lens morphology was evaluated under dissecting microscope. Glutathione (GSH), free protein thiol (PSH), and protein glutathionylation (PSSG) levels were measured to reflect the oxidative markers. Finally, we also examined the effects of grape powder on the nuclear factor erythroid 2–related factor 2 (Nrf2) pathway and its downstream antioxidant genes in the lens. Results: We found that 15% grape powder diet could significantly inhibit the onset as well as the severity of UV-induced cataracts. All mice in the regular diet control group developed severe epithelial and superficial anterior subcapsular cataracts two days after the UV radiation. On the other hand, grape powder diet in a dose-dependent manner prevented the lens from UV radiation-induced cataract progression. In the 15% grape powder diet group, the majority of lenses remained largely transparent. The GSH and PSH levels were much higher in the 15% grape powder diet group compared with that of the regular diet control group. The accumulation of PSSG, a marker for protein thiol oxidation, was largely inhibited in the 15% grape powder diet group. Interestingly, we also found that Nrf2 and its downstream targets including SOD, catalase, thioredoxin (Trx), and glutaredoxin 1 (Grx1) were significantly elevated in regular diet control groups due to the UV exposure. However, this UV-induced Nrf2 activation was largely inhibited in all three grape powder diet groups. Conclusions: Grape powder dose-dependently protected the lens from UV radiation-induced cataract development in mice. Its protective effects may involve directly regulating endogenous Nrf2 and its downstream target detoxifying/antioxidant genes, including SOD2, Catalase, Trx1 and Grx1.
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    Glucocorticoid-induced ocular hypertension leads to progressive retinal ganglion cell loss, impaired axonal transport and optic nerve degeneration in mice
    (2018-03-14) Kasetti, Ramesh; Patel, Pinkal; Sope, Amit; Zode, Gulab; Maddineni, Prabhavathi
    Purpose: Ocular hypertension (OHT) and secondary iatrogenic open angle glaucoma are the serious side effects of glucocorticoid (GC) therapy, which is used widely to treat various immune mediated diseases. We have previously developed a novel mouse model of GC-induced OHT using weekly periocular injections of potent GC, dexamethasone (Dex). The purpose of this study is to examine whether sustained Dex-induced OHT leads to glaucoma phenotype in mice. Methods: Three-month old C57BL/6J mice (n=30) were injected with either Dex-Acetate (200µg/eye) or vehicle suspension via periocular route, once in a week for 10-weeks. IOP was measured every week and pattern electro retinogram (pERG) was used to measure RGC function at 10-weeks post injections. Alexa Flour 594-cholera toxin B (CTB) was injected intravitreally, to trace the deficits in anterograde axon transport. Abnormal extracellular matrix (ECM) deposition in trabecular meshwork (TM) was assessed by immunostaining. RGC loss was analyzed by whole mount retina staining with RBPMS antibody and axon degeneration was examined by PPD staining. Results: Weekly injections of Dex but not vehicle caused sustained and pronounced IOP elevation in mice, starting from 1-week of injection (Δ ≥3.5mmHg IOP). In addition, Dex reduced the outflow facility (~30%) and also induced abnormal ECM proteins (fibronectin and collagen I) deposition in TM. pERG revealed significant deficits in RGCs function as evident from reduced pERG amplitudes (10µV v/s 25 µV) with increased N1 latency periods (140ms v/s 100ms) in Dex-injected mice compared to vehicle injected mice. Importantly, we observed a highly significant RGC loss in Dex-mice (loss was ~60% in periphery and ~50% in mid-periphery). Axon anterograde transport tracer CTB accumulated in ONH of Dex-mice, indicating deficits in axonal transport. PPD-stained cross sections of optic nerves showed severe axonal damage in Dex-mice, whereas no damage was observed in vehicle injected mice. Conclusions: These data suggest that our novel mouse model of periocular Dex-induced OHT develops glaucoma phenotype. Also, there are many clinical, morphological, and molecular similarities between our Dex-induced glaucoma model and POAG, making this mice model as an attractive model to study the specific aspects of POAG, including TM and RGCs pathology in glaucoma.
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    Crosstalk Between TGFβ2 and TLR4 in the Trabecular Meshwork
    (2018-03-14) McDowell, Colleen; Roberts, Amanda
    Purpose: The trabecular meshwork (TM) regulates aqueous humor outflow and intraocular pressure (IOP). The effects of TGFβ signaling pathways on the TM extracellular matrix (EÇM) have been extensively studied. Recently, we identified TGFβ2 and toll-like receptor 4 (TLR4) signaling crosstalk regulates changes in the TM ECM and mutation in Tlr4 rescues TGFβ2 -induced ocular hypertension in mice. Here, we investigated the role of an endogenous TLR4 ligand, FN-EDA, and a downstream signaling molecule of TLR4, NFκB, in TGFβ2 -induced ocular hypertension in mice. Methods: B6.FN-EDA-/- (n=18), B6.FN-EDA+/+/TLR4-/- (n=7), B6.FN-EDA-/-/ TLR4-/- (n=15), and C57BL/6J (n=11) mice were intravitreally injected with 2.0 μL Ad5.TGFβ2 (2.5x107 pfu) in one eye and the contralateral uninjected eye was used as a negative control. Likewise, we tested mice lacking the p50 subunit of NFκB (B6.Cg-NFκB1tm1Bal/J) (n=7) and C57BL/6J (n=10) mice. IOP was measured using a TonoLab rebound tonometer on isoflurane-anesthetized mice for 42 days post-injection. Significance determined by one-way ANOVA at each time point. Results: Ad5.TGFβ2 significantly induced ocular hypertension in C57BL/6J mice in both experiments. In the first experimental cohort, Ad5.TGFβ2 significantly induced ocular hypertension in C57BL/6J mice starting at 7-days post injection and remained significant until 42 days post-injection (p Conclusions: These findings demonstrate that TLR4, the endogenous TLR4 ligand FN-EDA, and NFκB are necessary for TGFβ2 induced ocular hypertension in mice. These data provide potential new targets to lower IOP and to further explore the molecular mechanisms involved in the development of glaucomatous TM damage.
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    Transcorneal Permeability Pilot Studies
    (2018-03-14) Nguyen, Vien; Johnston, Joseph; Prokai-Tatrai, Katalin; Rahlouni, Fatima
    Purpose: Permeability of potential ocular agents across the cornea is important in evaluating their ability to enter the eye by the transcorneal route. Accordingly, the purpose of this study was to set up a transcorneal permeability protocol and develop the necessary analytical methods to evaluate flux differences among test agents across cornea from different species. Methods: Corneas from rat, pig and rabbit were used. Jacketed vertical diffusion cells were used to test transcorneal permeability. Two test compounds of comparable molecular volume but differing in lipophilicity (measured by the logarithm of the n-octanol/water partition coefficient, logP) by approximately two log units were chosen for this pilot study. Once cornea and cell chambers were equilibrated to 35°C, cornea was mounted and test compounds at a given concentration either in saline or in saline containing a permeability enhancer excipient were placed in the donor chamber. The amount of test agents in the receiver chamber versus time was measured based on methods developed in our laboratory and using LC-MS/MS selected reaction monitoring on a TSQ Quantum Ultra (Thermo) connected to a Surveyor HPLC system (Thermo). Quantification of each test compound was performed based on the principles of stable isotope dilution. Flux was calculated, based on the principles of diffusion testing. Results: We were able to establish the transcorneal permeability procedure for testing the diffusion of compounds across the cornea. In addition, selected reaction monitoring LC-MS/MS quantification methods were developed for the test compounds. Of our two test compounds in this pilot study, we were able to show that the flux across the cornea for test compound with intermediate lipophilicity was approximately one log unit higher for all species when saline vehicle was used and about 0.5 log unit higher when a permeability enhancer excipient was used, compared to those of test agent with high lipophilicity (logP about 4). Conclusions: This pilot study showed the establishment of a protocol for a convenient evaluation of the transcorneal permeability of test compounds quantified by LC-MS/MS analyses. This study was supported by NIH grant R01EY027005 (KPT)
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    Bi-functional small molecule with both IOP lowering and neuroprtective activity to treat glaucoma.
    (2018-03-14) Stankowska, Dorota; Millar, Cameron; Chaphalkar, Renuka; Li, Linya; Ellis, Dorette; Yorio, Thomas; Acharya, Suchismita
    Purpose: The multifaceted pathology associated with glaucoma is difficult to treat by monotherapy such as lowering intraocular pressure (IOP). Oxidative stress is involved in IOP elevation and retinal ganglion cell (RGC) death possibly via decreased activity of antioxidant enzymes. Our hypothesis is that, a small hybrid molecule SA-2 and its PLGA encapsulated nanoparticle (NP) drug delivery vehicle (SA-2-NPs) possessing a nitric oxide (NO) donating group and a redox antioxidant moiety will lower IOP as well as possess neuro/cytoprotective potential. Methods: IOP-independent neuroprotection of RGCs: Mice (C57BL6, 12 weeks, n=8) were anesthetized and the optic nerve crush (ONC) was performed on one eye followed by intravitreal injection of 2ml of 2% SA-2 formulated in PBS or vehicle to the crushed eye at day 0 and 3. At day 7, pattern electroretinogram (PERG) was performed, following which retinas were flat mounted. Number of surviving, RBPMS positive RGCs were counted. IOP lowering effect: Nine Brown Norway normotensive rats (n=3 per each group) were used to evaluate the IOP-lowering properties of SA-2-NPs under a masked protocol. Topical eye drops (30 µL/drop) containing: A) Vehicle (PBS), B) Travoprost (0.004%)-positive control or C) SA-2-NPs (100 µg/mL) formulated in PBS were administered in three rats and IOP was measured using the TonoLab rebound tonometer at various time points: 0, 3, 6, 24, 48 and 72 h post-dosing. The entire dosing schedule was repeated 3 times in each rat. Results: Compound SA-2 treatment was significantly (t-test, p 2 vs SA-2 treated group (2100 cells/cm2) and was comparable to the untreated control (2650 cells/cm2). The data are given as the mean ± SEM; n= 3-4. PLGA encapsulated SA-2-NPs (100mg) statistically (t-test, p Conclusion: Taken together, our results are consistent with our hypothesis that this novel class of hybrid compound and its PLGA encapsulated nanoparticles will decrease IOP and protect RGCs from cell death. Further structure optimization of the lead compound, dose optimization, IOP lowering study in ocular hypertensive rodent models are underway.