Purpose: To generate a model of chronic glaucoma in rats, by means of a single injection that simulates the pathology that occurs in humans. Methods: A total of 47 Long‐Evans rats of both sexes were used; 30 rats received an intracameral injection of a suspension of fibronectin‐loaded poly‐lactic‐glycolic acid microspheres into the right eye, and the other 17 served as controls. They were followed up for 24 weeks, evaluating intraocular pressure (IOP) with a rebound tonometer, neuro‐retinal structure by optical coherence tomography (OCT) with segmentation protocols for the analysis of the entire retina, the ganglion cell layer (GCL) and the peripapillary retinal nerve fibre layer (pRNFL); as well as retinal functionality by electroretinography (ERG). Results: The IOP of the induced eyes increased progressively and chronically (11.64 ± 1.43 to 21.89 ± 3.94 mmHg) compared to the controls (p = 0.025) and with higher levels than the contralateral eyes (p < 0.05) until week 20, when this trend reversed. The induced eyes showed fluctuations in OCT retinal thickness over time. A trend of less thickness in the retina and GCL was measured in the induced eye and its contralateral eye; but at the end of the study, greater thicknesses were quantified than in the control eyes (p = 0.036). In addition, a lower ERG signal was recorded in the induced eyes. Ganglion cell functionality progressively decreased and was lower than contralateral eyes and control eyes at 12 and 24 weeks (p < 0.05). Males showed higher IOP (p < 0.05), greater thicknesses in the retina and lesser in the GCL and pRNFL (p < 0.05), with decreased functionality at 12 and 24 weeks compared to females. Conclusions: A minimally invasive chronic glaucoma model was obtained using single‐injection by pharmaceutical technology, which produced a progressive increase in intraocular pressure and structural and functional neuro‐retinal damage.
Purpose: To evaluate the intravitreal injection of PLGA/VitE non‐loaded microspheres as a potential platform to deliver neuroprotective active compounds in a chronic glaucoma animal model. In this model, a gradual increase in intraocular pressure (IOP) is observed due to physical and pharmacological damage to the trabecular meshwork by the intracameral injection of fibronectin‐loaded PLGA microspheres. Methods: Microspheres (Ms) employed to create the animal model were made by a double water‐in‐oil‐in‐water emulsion technique where fibronectin was included in the inner aqueous phase (F‐Ms). PLGA/VitE blank Ms (B‐Ms) were made by a single oil‐in‐water emulsion. Ms were characterized regarding mean particle size, particle size distribution and morphology. In vivo studies were carried out in Long‐Evans rats divided into two groups: control (n = 30) and treated (n = 20). To create the model, both groups received a single intracameral injection of F‐Ms suspension (10% w/v) in the right eye (RE). Two weeks later, a suspension of B‐Ms (5% w/v) was intravitreally injected into the RE (treated group). Clinical signs and IOP were assessed in both groups for 12 weeks. Results: Ms were spherical with a smooth surface and some porous in the case of F‐Ms and with a typical “golf‐ball like” surface in the case of B‐Ms. Size distribution was unimodal with an average size of 16.45 ± 0.37 μm for F‐Ms and 29.95 ± 0.42 μm for B‐Ms. Both ocular injections were well tolerated. In all cases, IOP values significantly increased over time (p < 0.05) with a rise of 6–7 mmHg at 12 weeks. No significant differences were found between the IOP in the treated and the control group. Conclusions: Intravitreal injections of B‐Ms were well tolerated and did not affect the IOP increase of the animal model. These findings underline the suitability of the glaucoma animal model created by the intracameral injection F‐Ms for the evaluation of treatments based on intravitreal injection of PLGA/VitE‐based microsystems.
PurposeTo quantify changes in visual function parameters and the macular neuroretina of patients with Fibromyalgia (FM) over a period of 5 years, and to compare with changes in healthy controls.MethodsEighty patients with FM and 38 age and sex‐matched healthy controls were recruited for the study. Only one eye per subject was randomly selected and included. All subjects underwent evaluation of visual acuity (VA) by ETDRS charts, contrast sensitivity vision (CSV) using CSV 1000E test and retinal evaluation using Spectralis Optical coherence tomography (OCT). All subjects were re‐evaluated after 5 years to quantify changes in visual function parameters and ganglion cell layer (GCL) and retinal nerve fiber layer (RNFL) thickness. Association between progressive structural, functional and disease severity changes was analysed. Additionally, in order to analyse progression depending on disease phenotype, the patients were classified into three different groups and compared.ResultsAfter a period of 5 years of follow‐up, patients with FM showed worse low contrast VA (p = 0.024), and low frequency CSV (p = 0.004). Furthermore, they presented a progressive decrease affecting the GCL thickness (nasal 1, p = 0.004; temporal 1, p < 0.001; inferior 1, p = 0.001) and the RNFL (nasal 1 and 2, p < 0.001; superior 1, p < 0.001; and inferior 1, p = 0.002). Changes affecting the GCL were correlated with progression in disease severity scores (EQ‐5D, r = 0.560, p < 0.001; FIQ, r = −0.470, p = 0.003). Correlations between structural changes and disease severity scores were only observed in the atypical and biologic phenotypes.ConclusionsPatients with FM present progressive retinal neurodegeneration and visual function changes with time. The evaluation of visual parameters and GCL/RNFL thickness using SD‐OCT could constitute a useful tool in monitoring FM progression.
Purpose: The subclinical immune response mediates a homeostatic role in healthy situations, but in pathological situations it misbalances. Glaucoma is a multifactorial pathology in which immunity is involved. Optical coherence tomography (OCT) detects the immune response in vitreous as hyperreflective opacities. The aim of this study is to monitor vitreous parainflammation in two steroid induced glaucoma (SIG) animal models, comparing both sexes and healthy controls over 6 months. Methods: Two SIG models were induced by injecting a suspension of PLGA‐Ms loaded with dexamethasone or dexamethasone/fibronectine into the anterior chamber of rat eyes. Intraocular pressure (IOP) was measured by rebound tonometer every week and vitreous‐retinal interface was evaluated with OCT at 0, 4, 8, 12, 18 and 24 weeks of follow‐up. Vitreous images were exported as AVI videos and then we designed a computational analysis that characterizes and classifies the vitreous hyperreflective opacities based on their size into isolated cells (10 microns2), non‐activated cells (10–50 microns2), activated cells (50–250 microns2) and complexes (>250 microns2). Vitreous/retinal pigment epithelium (VIT/RPE) relative intensity, opacity/cell intensity, eccentricity and orientation were analysed. Results: SIG eyes showed tendency of greater intensity, and number of vitreous opacities (p < 0.05) with dynamic fluctuations. Both SIG models showed an antinflammatory profile, with non‐activated cells as the highest population over the study. However, smaller opacities (isolated cells) seems to be the first responder to noxa since they were the most rounded (recruitment) coinciding with IOP peak increase, showed the highest mean intensity (intracellular machinery) even in contralateral eye, and the greatest change in orientation (motility). Conclusions: Study the features of hyper‐reflective opacities in vitreous using OCT could be a biomarker of glaucoma onset and progression.
Purpose: To evaluate changes in visual function and anatomical structures in the neuroretina of patients diagnosed with Alzheimer's disease (AD) in comparison with healthy controls. Methods: A total of 25 eyes of 13 AD patients and 80 eyes of 40 healthy subjects were analysed. Best corrected visual acuity (BCVA) was assessed in different contrast situations (100%, 2.5%, 1.25%) with ETDRS chart (Early Treatment Diabetic Retinopathy Study). Also, retinal nerve fibre layer (RNFL) and ganglion cell layer (GCL) thickness were analysed using Spectralis and Triton optical coherence tomography (OCT), globally and by sectors, both in peripapillary and macular area. Results: A statistically significant decrease was found in BCVA in AD patients in comparison with controls (p < 0.001), specifically in 100% and 1.25% contrast charts. Regarding structural analysis, a significant reduction in retinal thickness was found in AD patients in comparison with controls. Global thickness was found to be significantly thinner in peripapillary retina in Triton OCT (p < 0.001). In a similar way, macular GCL, both in Triton and Spectralis OCT, showed a significant thinning (p < 0.001) in global and sectorial analysis. RNFL showed a significant tendency towards thinning, but specifically in infero‐temporal sector of macular area in Spectralis OCT (p < 0.001). Conclusions: The neurodegeneration that AD produces to the brain affects the retina in a parallel way, and that can be objectified by measuring BCVA parameters and thickness measurements in OCT. Compared to healthy controls, AD has a significant thinning in several neuroretinal layers, which can be considered a potential diagnostic tool considering that OCT is a quick, reproducible, non‐invasive test.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.