Reduced Posology of an Ophthalmic Hydrogel Containing Dexamethasone/Netilmicin to Prevent and Treat Ocular Inflammation After Cataract Surgery: Efficacy and Tolerability.

INTRODUCTION: To demonstrate efficacy and safety of an ophthalmic hydrogel formulation of netilmicin/dexamethasone, containing xanthan gum twice a day (b.i.d.) versus netilmicin/dexamethasone eye drops four times a day (q.i.d) to treat inflammation and prevention of infection after cataract surgery. METHODS: Patients undergoing phacoemulsification with intraocular lens implantation (IOL) were randomised in two groups: group 1, twice daily (b.i.d.) dexamethasone 0.1%/netilmicin 0.3% (Netildex) ophthalmic gel; group 2, four times daily (q.i.d.) dexamethasone 0.1%/netilmicin 0.3% (Netildex) eye drops. Both treatments were administered for 14 days after surgery. Patients were evaluated before surgery, on the day of surgery and at 1, 7, 15 and 60 postoperative days. The primary efficacy endpoint was evaluation of cellularity and flare in the anterior chamber through slit-lamp biomicroscopy 7 days after surgery. Secondary endpoints included: presence of signs/symptoms of postoperative ocular inflammation and incidence of infection. RESULTS: One hundred seventy-three patients were randomised and 168 were evaluable. Flare and cellularity were resolved at day 7 in 92.5% of patients and almost completely by day 15. In both intent to treat (ITT) and per-protocol (PP) populations, the efficacy analysis demonstrated that the gel formulation administered twice a day was non-inferior to the eye drops administered four times a day. For ITT analysis, the lower limit of the 97.5% confidence interval (- 0.0535) was greater than the non-inferiority limit of -0.10. For the PP analysis, the lower limit of the 97.5% confidence interval (- 0.0526) was greater than the non-inferiority limit of - 0.10. The patient's global tolerability and reported symptoms were similar between treatment groups. No microbial load and no safety events were observed. CONCLUSIONS: Efficacy of the gel reduced posology (twice a day) is not inferior to four times a day eye drops. Both treatments were well tolerated and efficacious. The new reduced posology hydrogel formulation may improve patient compliance and quality of life. TRIAL REGISTRATION: Eudract: 2016-0021138-63; ClinicalTrial.gov: NCT029738880.

Do Nutrients and Nutraceuticals Play a Role in Diabetic Retinopathy? A Systematic Review.

Diabetic retinopathy (DR) is a multifactorial neuro-microvascular disease, whose prevalence ranges from 25% to 60% of subjects affected by diabetes mellitus, representing the main cause of legal blindness in adults of industrialized countries. The treatment of advanced stage of DR is based on invasive and expensive therapies, while few strategies are available for the early stage or prevention. The mechanisms underlying DR involve a complex interplay between the detrimental effects of hyperglycemia, dyslipidemia, hypoxia, and oxidative stress, providing several pathways potentially targeted by nutrients and nutraceuticals. In this study, we conducted a systematic review of observational and interventional studies, evaluating the effect of nutrients and/or nutraceuticals on the risk of DR and their potential use for the treatment of patients with DR. The analysis of the 41 included studies (27 observational and 14 interventional studies) suggests a promising preventive role of some nutrients, in particular for vitamins B (i.e., B1 and B12), D, and E. However, further investigations are necessary to clarify the potential clinical application of nutraceuticals in the prevention and treatment of DR.

Preclinical study of a new matrix to help the ocular surface in dry eye disease.

Dry eye disease (DED), a multifactorial disease of the tears and ocular system, causes loss of tear film homeostasis with damage to the ocular surface. This study aimed to assess whether a peculiar matrix based on sodium hyaluronate (HA), xanthan gum (XNT), glycine (GLY) and betaine (BET) as osmoprotectants, could be involved in biological responses. Wound healing assay on human corneal epithelial (HCE) cells in monolayer showed a synergistic effect of the combination of HA + XNT (**p ≤ 0.01) together with an efficient extracellular matrix remodeling of the formulation in SkinEthic™ HCE 3D-model sought by integrin beta-1 (ITGß1) expression and morphological analysis by hematoxylin and eosin (H&E), compared to a reference marketed product. The synergistic effect of HA + XNT + GLY + BET showed an antioxidant effect on HCE cells (***p ≤ 0.001). Real-time PCR analysis showed that the combination of GLY + BET seemed to ameliorate the effect exhibited by the single osmoprotectants in reducing tumor necrosis factor-alpha (TNFα, #p ≤ 0.05), interleukin-1 beta (IL1ß, ####p ≤ 0.0001) and cyclooxygenases-2 (COX2, ####p ≤ 0.0001) genes in SIRC cells under hyperosmotic stress. Furthermore, pretreatment with XNT, alone and in combination (##p ≤ 0.01), reduced COX2 expression in human non-small cell lung cancer cells (A549). Finally, the formulation was well-tolerated following q.i.d. ocular administration in rabbits during a 28-day study. Due to the synergistic effect of its components, the matrix proved able to repair the ocular surface restoring cell homeostasis and to protect the ocular surface from pro-inflammatory pathways activation and oxidative damage, thus behaving as a reactive oxygen species (ROS) scavenger.

Assessment of a New Nanostructured Microemulsion System for Ocular Delivery of Sorafenib to Posterior Segment of the Eye.

Eye drop formulations allowing topical treatment of retinal pathologies have long been sought as alternatives to intravitreal administration. This study aimed to assess whether a novel nanostructured microemulsions system (NaMESys) could be usefully employed to deliver sorafenib to the retina following topical instillation. NaMESys carrying 0.3% sorafenib (NaMESys-SOR) proved to be cytocompatible in vitro on rabbit corneal cells, and well-tolerated following b.i.d. ocular administration to rabbits during a 3-month study. In rats subject to retinal ischemia-reperfusion, NaMESys-SOR significantly inhibited retinal expression of tumor necrosis factor-alpha (TNFα, 20.7%) and inducible nitric oxide synthase (iNos, 87.3%) mRNAs in comparison to controls. Similarly, in streptozotocin-induced diabetic rats, NaMESys-SOR inhibited retinal expression of nuclear factor kappa B (NFκB), TNFα, insulin like growth factor 1 (IGF1), IGF1 receptor (IGF1R), vascular endothelial growth factor receptor 1 (VEGFR1) and 2 (VEGFR2) mRNAs by three-fold on average compared to controls. Furthermore, a reduction in TNFα, VEGFR1 and VEGFR2 protein expression was observed by western blot. Moreover, in mice subject to laser-induced choroidal neovascularization, NaMESys-SOR significantly inhibited neovascular lesions by 54%. In conclusion, NaMESys-SOR was shown to be a well-tolerated ophthalmic formulation able to deliver effective amounts of sorafenib to the retina, reducing proinflammatory and pro-angiogenic mediators in reliable models of proliferative retinopathies. These findings warrant further investigations on the full therapeutic potential of NaMESys-SOR eye drops, aiming to address unmet needs in the pharmacotherapy of retinal neovascular diseases.

Complement System and Age-Related Macular Degeneration: Implications of Gene-Environment Interaction for Preventive and Personalized Medicine.

Age-related macular degeneration (AMD) is the most common cause of visual loss in developed countries, with a significant economic and social burden on public health. Although genome-wide and gene-candidate studies have been enabled to identify genetic variants in the complement system associated with AMD pathogenesis, the effect of gene-environment interaction is still under debate. In this review we provide an overview of the role of complement system and its genetic variants in AMD, summarizing the consequences of the interaction between genetic and environmental risk factors on AMD onset, progression, and therapeutic response. Finally, we discuss the perspectives of current evidence in the field of genomics driven personalized medicine and public health.

Curcumin Modulates DNA Methyltransferase Functions in a Cellular Model of Diabetic Retinopathy.

Hyperglycaemia-induced oxidative stress appears to be involved in the aetiology of diabetic retinopathy (DR), a major public health issue, via altering DNA methylation process. We investigated the effect of hyperglycaemia on retinal DNA methyltransferase (DNMT) expression in diabetic mice, using Gene Expression Omnibus datasets. We also evaluated the effect of curcumin both on high glucose-induced reactive oxygen species (ROS) production and altered DNMT functions, in a cellular model of DR. We observed that three months of hyperglycaemia, in insulin-deficient Ins2 Akita mice, decrease DNMT1 and DNMT3a expression levels. In retinal pigment epithelium (RPE) cells, we also demonstrated that high glucose-induced ROS production precedes upregulation of DNMT expression and activity, suggesting that changes in DNMT function could be mediated by oxidative stress via a potential dual effect. The early effect results in decreased DNMT activity, accompanied by the highest ROS production, while long-term oxidative stress increases DNMT activity and DNMT1 expression. Interestingly, treatment with 25 µM curcumin for 6 hours restores ROS production, as well as DNMT functions, altered by the exposure of RPE to acute and chronic high glucose concentration. Our study suggests that curcumin may represent an effective antioxidant compound against DR, via restoring oxidative stress and DNMT functions, though further studies are recommended.

Resveratrol Modulates SIRT1 and DNMT Functions and Restores LINE-1 Methylation Levels in ARPE-19 Cells under Oxidative Stress and Inflammation.

The role of epigenetic alterations in the pathogenesis of retinal degenerative diseases, including age-related macular degeneration (AMD), has been pending so far. Our study investigated the effect of oxidative stress and inflammation on DNA methyltransferases (DNMTs) and Sirtuin 1 (SIRT1) functions, as well as on long interspersed nuclear element-1 (LINE-1) methylation, in human retinal pigment epithelial (ARPE-19) cells. Therefore, we evaluated whether treatment with resveratrol may modulate DNMT and SIRT1 functions and restore changes in LINE-1 methylation. Cells were treated with 25 mU/mL glucose oxidase (GOx) or 10 µg/mL lipopolysaccharide (LPS) to mimic oxidative or inflammatory conditions, respectively. Oxidative stress decreased DNMT1, DNMT3a, DNMT3b, and SIRT1 expression (p-values < 0.05), as well as total DNMTs (-28.5%; p < 0.0001) and SIRT1 (-29.0%; p < 0.0001) activities. Similarly, inflammatory condition decreased DNMT1 and SIRT1 expression (p-values < 0.05), as well as total DNMTs (-14.9%; p = 0.007) and SIRT1 (-20.1%; p < 0.002) activities. Interestingly, GOx- and LPS-treated cells exhibited lower LINE-1 methylation compared to controls (p-values < 0.001). We also demonstrated that treatment with 10 µM resveratrol for 24 h counteracted the detrimental effect on DNMT and SIRT1 functions, and LINE-1 methylation, in cells under oxidative and inflammatory conditions. However, further studies should explore the perspectives of resveratrol as a suitable strategy for the prevention and/or treatment of retinal degenerative diseases.

Effects of a new lipid tear substitute in a mouse model of dry eye.

PURPOSE: The present investigation is aimed to evaluate the effect of a new lipid artificial tear on tear volume and ocular surface signs in a mouse model of dry eye and to test the hypothesis that the combined application with sodium hyaluronate can improve the performance of the treatments. METHODS: A new oil-in-water emulsion, a 0.2% sodium hyaluronate solution, or their combined administration were given to dry eye mice maintained in a controlled environment chamber and treated with scopolamine (0.75-mg transdermal patch). Mice were treated 4 times a day with (a) sodium hyaluronate, (b) emulsion, and (c) sodium hyaluronate followed by emulsion. A control group of mice exposed to controlled environment chamber remained untreated (CTRL+). Tear volume and corneal damage were assessed after 3 and 7 days of treatment by cotton thread test and fluorescein staining. RESULTS: As regards tear volume, sodium hyaluronate did not show a statistically significant effect at either end point; the emulsion was effective after 7 days, whereas their combined administration counteracted the lacrimal decrease induced by the model both at 3 and 7 days. Corneal damage was reduced in all treated groups with respect to CTRL+. This effect was statistically significant after 3 days when the emulsion alone or in combination with sodium hyaluronate was used, while hyaluronate improved this clinical sign after 7 days. CONCLUSIONS: Our data suggest that the new lipid tear substitute can be used to treat clinical signs of dry eye and that the combined administration with hyaluronate can decrease the lag time before the effect, when the evaporative and the aqueous-deficient components are present.