Long-term efficacy and safety profile of multiple injections of intravitreal dexamethasone implant to manage diabetic macular edema: A systematic review of real-world studies

Pullulan as a sustained release carrier for ocular drug delivery: a review

Pullulan, an exopolysaccharide, obtained from the fungus Aureobasidium pullulans, is a non-ionic, hydrophilic, biodegradable, biocompatible, and tolerogenic polymers that is used for the formulation of bioconjugates in the therapeutic delivery to target different cells and tissues. It is known to possess outstanding film-casting qualities and can produce a clear and biodegradable film. Furthermore, appropriate derivatizing pullulan provides active surfaces that facilitate binding with active pharmaceutical ingredients to the polymer backbone to produce micro/nanoparticulate systems for controlled or sustained drug release. Ophthalmic problems like glaucoma, age-related macular degeneration, and cataracts are very prevalent across the globe, and their treatment options mainly include conventional topical solutions and gels, which possess very low drug-contact time and poor bioavailability, leading to frequent dosing and patient incompliance. Sustained release dosage forms like ocuserts, ocular films, and in-situ gels can help in achieving the intended therapeutic outcomes for an extended duration by minimizing the number of doses. Here, we present a comprehensive critical review of the utilization and application of pullulan, together with its derivatives, to combat problems with ocular medication administration. This article also provides insight for further research on this topic to utilize its advantages to the fullest in the future for improved delivery of therapeutics in the treatment of ocular disorders.

Blockade of P2X7 receptors preserves blood retinal barrier integrity by modulating the plasmalemma vesicle-associated protein: Implications for diabetic retinopathy

BACKGROUND AND PURPOSE

Plasmalemma vesicle-associated protein (PLVAP) regulates transcytosis in vascular endothelial cells. PLVAP expression is increased in pathological conditions, such as diabetic retinopathy. P2X7 receptor antagonists have been shown to preserve blood-retinal barrier (BRB) integrity. Here, we have tested the hypothesis that PLVAP expression is tightly linked to P2X7 receptor activity, leading to breakdown of the BRB in an in vitro model of diabetic retinopathy.

EXPERIMENTAL APPROACH

We integrated network approaches with an in vitro model of diabetic retinopathy using primary human retinal microvascular endothelial cells (HRMECs). Cells were treated with a P2X7 receptor antagonist, JNJ47965567, and expression of several genes predicted to belong to the P2X7 receptor signalling network were assessed. Levels and localisation of PLVAP, VE-cadherin and zonula occludens-1 (ZO-1) in HRMECs were evaluated. In vivo, the effects of JNJ47965567 on PLVAP expression in the retinas of diabetic mice were assessed.

KEY RESULTS

High levels of glucose increased PLVAP expression in HRMECs, which was blocked by JNJ47965567. Furthermore, JNJ47965567 preserved VE-cadherin and ZO-1. In the choroidal vasculature of diabetic mice, PLVAP immunostaining was increased, compared to levels in non-diabetic mice. This increase was significantly attenuated by treatment with JNJ47965567 CONCLUSIONS AND IMPLICATIONS: This study showed that P2X7 receptor signalling is an important component of a complex gene regulatory network, including PLVAP, mediating the pathophysiology of diabetic retinopathy. The P2X7 receptor antagonist JNJ47965567 showed a good pharmacodynamic profile, suggesting that this approach could be of value in the treatment of diabetic retinopathy.

α1D Adrenergic Receptor Antagonism Protects Against High Glucose-Induced Mitochondrial Dysfunction and Blood Retinal Barrier Breakdown in ARPE-19 Cells

Diabetic retinopathy (DR) is a microvascular complication of diabetes mellitus and a leading cause of blindness in the working-age population. Current pharmacological treatments counteract DR's later stages without targeting the earlier disease phases. Using computational approaches, our group previously identified the α1D and α2C adrenoceptors (α1DR and α2CR) as new putative drug targets for DR. Therefore, the aim of this work was to validate the role of these receptors in an in vitro model of DR, i.e., retinal pigmented epithelial cells (ARPE-19) challenged with high glucose (HG, 50 mM). We examined the effects of selective α1DR and α2CR agonists and antagonists on hyperglycemia-induced mitochondrial dysfunction and blood retinal barrier breakdown. Seahorse XFe was employed to assess the oxygen consumption rate and extracellular acidification rate. The integrity of the ARPE-19 barrier was evaluated through transepithelial electrical resistance measurements and a sodium fluorescein permeability test. α1DR pharmacological modulation through the α1DR antagonist BMY 7378 (0.1-1 µM, 24 h), but not α2CR, significantly attenuated HG-induced mitochondrial dysfunction. BMY 7378 (0.1-1 µM, 48 h) also prevented HG-mediated damage to retinal epithelial integrity. In contrast, the α1DR agonist phenylephrine (1-10 μM, 24 h) further reduced ARPE-19 mitochondrial activity compared to HG, indicating that α1D activation is directly implicated in DR-mediated mitochondrial dysfunction. In conclusion, the current in vitro study validated α1DR as a pharmacological target for DR.

Intravitreal dexamethasone implant (Ozurdex®) findings over time: ultrasound and ultra-widefield fundus photography

BACKGROUND

Ozurdex® (Allergan®, AbbVie Company, North Chicago, Illinois, EUA), is composed of 0.7 mg of dexamethasone, fused in a solid biodegradable PLGA polymer, whose degradation occurs naturally in the vitreous cavity, usually in six months after its application.

METHODS

In this study, we included patients aged ≥ 18 years with one or two eyes who had an indication for Ozurdex® implants. Eyes submitted to Ozurdex® application were evaluated in the first hour after the injection via transpalpebral contact B-scan ocular ultrasonography (Aviso® or Compact Touch®, Quantel®) and non-mydriatic ultra-widefield fundus photography (California®, Optos®) performed sequentially. The exams were executed using similar parameters and techniques, by the same ophthalmologist, after every 45 days, until the end of 180 days. The programed visits were the initial (tagged D0) and sequential (D45, D90, D135, and D180) visits, with a possible variance of seven days, before or after. The ultrasonographic Ozurdex® findings evaluated were: non-quantitative: structure, height, reflectivity, artifact production, location, and movement; and quantitative: length and thickness. Ultra-widefield fundus photography parameters were: Ozurdex® visualization, location, and structure.

RESULTS

The B-scan showed the implant initially, at the D0 visit, as a well-delimited and homogeneously highly reflective linear and continuous structure. On D45, Ozurdex® implants presented with low internal reflectivity and irregularity in the limits. On D90, D135, and D180, reductions in the length and thickness progressively lessened, leading to the final appearance of a small highly reflective clust. Over time, all the implants presented reductions in length and thickness. The mean length at D0 was 7.42 ± 0.39 mm and at the final visit (D180) it was 1.50 ± 0.47 mm. The mean thickness at D0 was 0.77 ± 0.13 mm and at the final visit (D180) it was 0.44 ± 0.18 mm.

CONCLUSIONS

Considering implant dimensions, the change in length over time was more evident than the change in thickness. In all the cases where visualization was possible, positive correlations with B-scan findings were found despite changes in patient position. These alterations evidenced in the Ozurdex® implant over time may be related to the degradation of the glucose polymer structure.

Diabetic Macular Oedema - Patient Characteristics and the Reality of Treatment in a German University Hospital

BACKGROUND

Diabetic macular oedema (DME) is associated with significant loss of visual acuity. Intravitreal VEGF inhibitor injection is the gold standard in treating this disease; second-line treatment consists of intravitreal steroid injections. This treatment has already undergone extensive investigation in large randomised controlled trials. The aim of this study is to evaluate patient population and treatment options in a real-world setting.

MATERIAL AND METHODS

A retrospective analysis was conducted on data from 176 eyes in 114 patients diagnosed with diabetic macular oedema who had received at least one intravitreal injection during 2018 at Marburg University Hospital Department of Ophthalmology. The analysis examined demographic characteristics, prior treatment, and treatments performed as well as visual acuity and central retinal thickness development during therapy. Multiple linear regression analyses were used to investigate the influence of different variables on changes in dependent variables in visual acuity (logMAR), changes in retinal thickness (µm), and number of injections, while also taking interactions between the independent variables themselves into account.

RESULTS

Patients were on average 64.45 ± 13.79 years old and predominantly male (61.93%). Most (71.59%) had already been treated for DME. Baseline visual acuity averaged 0.42 logMAR ± 0.34; baseline central retinal thickness averaged 369.1 µm ± 118.81. A total of 688 intravitreal injections were administered at 3.91 ± 2.22 per eye during the study period. Visual acuity improved by 0.04 logMAR ± 0.18 on average; eyes with poorer baseline visual acuity showed a greater increase in visual acuity. CRT values decreased by 44.54 µm ± 133.95 on average. Eyes with higher baseline values showed greater reduction. Using regression analysis, this is the first study to demonstrate that eyes may continue to require additional injections after prior treatment.

CONCLUSION

This study demonstrated the reality of treatment for patients with diabetic macular oedema at a German university clinic as accurately as possible. We were able to demonstrate the differences from RCTs and the characteristics of the patient cohort.

Intravitreal therapy for the management of diabetic retinopathy: A concise review

Diabetic retinopathy (DR) is a serious microvascular complication of diabetes mellitus and may result in irreversible visual loss. Laser treatment has been the gold standard treatment for diabetic macular edema and proliferative diabetic retinopathy for many years. Of late, intravitreal therapy has emerged as a cornerstone in the management of DR. Among the diverse pharmacotherapeutic options, anti-vascular endothelial growth factor agents have demonstrated remarkable efficacy by attenuating neovascularization and reducing macular edema, thus preserving visual acuity in DR patients.

Investigation of Antibacterial Coatings Based on Chitosan/Polyacrylic Acid/Chlorhexidine for Orthopedic Implants

Antibacterial coatings on model silicon wafers and implants, based on chitosan (CHI), poly(acrylic acid) (PAA), and the antibacterial agent chlorhexidine digluconate (CHX), were obtained using a layer-by-layer assembly method. The surface roughness and 2D and 3D images of the surfaces of CHI/PAA/CHX coatings obtained from different pH assemblies were investigated by atomic force microscopy, revealing that pH 6 enabled optimal inclusion of CHX in the multilayer film. The structure and elemental composition before and after implementation of CHX into the coating were investigated via scanning electron microscopy and energy-dispersive X-ray spectroscopy. The obtained films exhibited antimicrobial efficacy against Staphylococcus aureus and Staphylococcus epidermidis. The effects of CHX concentration and duration of contact with the coating on bacterial activity were investigated, and the quantitative release of CHX from coated implants in phosphate buffer was determined as a function of the incubation time. The biocompatibility of the PAA/CHI/CHX coatings was investigated using human mononuclear cells (HMNCs) and quantified using an MTT assay. HMNCs demonstrated high viability in eluted solutions obtained from implants coated with PAA/CHI/CHX (0.025%) and PAA/CHI/CHX (0.0125%), while the extract of implants coated with PAA/CHI/CHX (0.05%) induced slight cytotoxicity.

Ophthalmic corticosteroids-related adverse events: the FDA adverse event reporting system (FAERS) database pharmacovigilance study

Background

Corticosteroids are extensively used in ophthalmology, particularly for treating various inflammatory conditions. Despite their effectiveness, prolonged or high-dose corticosteroid use is associated with significant adverse drug reactions (ADRs), such as increased intraocular pressure, cataract formation, and secondary infections. However, there is currently no systematic study comparing the side effects of ophthalmic corticosteroids. This study aims to investigate the safety profiles of ophthalmic corticosteroids through pharmacovigilance analysis using the FDA Adverse Event Reporting System (FAERS) database.

Methods

We conducted a retrospective analysis of ADR reports related to commonly used ophthalmic corticosteroids from the FAERS database, covering the period from Q1 2004 to Q4 2023. Clinical features such as gender, age, administration route, and dosage form were also analyzed. Signal detection methods, including Reporting Odds Ratio (ROR), Proportional Reporting Ratio (PRR), Bayesian Confidence Propagation Neural Network (BCPNN), and the Multi-Item Gamma Poisson Shrinker (MGPS), were used to identify potential safety signals.

Results

A total of 9,854 ADRs related to ophthalmic corticosteroids were retrieved, with the most frequently reported drugs being Ozurdex (1,784 cases), Lotemax (3,239 cases), and Durezol (2,789 cases). Women accounted for a higher proportion of ADRs across most corticosteroids. ADR induction time analysis results showed that ADRs tend to occur in the early stages of drug use. The most common ophthalmic ADRs identified included eye inflammation, cataract, visual impairment, uveitis, eye pain, blurred vision, and retinal detachment. Additionally, Maxidex has been linked to endocrine disorders, while Ozurdex, Iluvien, and Triesence exhibited significant signals for product issues, likely related to their intraocular injection procedures. Notably, cataract was the most common PT among these drugs.

Conclusion

Our study reveals significant safety concerns related to using ophthalmic corticosteroids, particularly regarding adverse reactions that can impact visual function. These findings highlight the need for careful monitoring and individualized treatment plans to minimize the risk of ADRs in patients receiving corticosteroid therapy. Future studies combining FAERS data with large-scale clinical research are needed to explore these safety concerns further.

ILUVIEN® in diabetic macular edema that persists or recurs despite treatment: Results from the Retina.pt® RIVER audit

PURPOSE

Persistent diabetic macular edema (DME) remains a problem in clinical practice, with many patients having a suboptimal response to the standard of care (SOC). Evidence supports the long-term efficacy of intravitreal fluocinolone acetonide (FAc) implant (ILUVIEN®) in patients that have responded sub-optimally, although there is still scarce data from real-world Portuguese practices. We aimed to monitor the current SOC in selected Portuguese practices prior to FAc implantation and then assess the long-term effectiveness and safety of the FAc implant.

SETTINGS

The study included patient data from five Portuguese public hospitals.

DESIGN

This was a non-interventional, multicenter audit of data collected from Retina.pt registry from patients with persistent or recurrent DME despite treatment.

METHODS

Outcome measures included changes in best-corrected visual acuity (BCVA), central macular thickness (CMT), and intraocular pressure (IOP). Results were compared at regular times over 36 months.

RESULTS

This study included 222 eyes from 152 patients. A significant decrease in BCVA (P < 0.001) and a significant increase in CMT (P = 0.013) were observed prior to FAc. A significant increase in BCVA was registered at 6 months after FAc implant administration (P < 0.001), which was maintained during follow-up. No relevant changes in IOP were observed. Treatment burden was reduced as a result of treatment with FAc (P < 0.001 for anti-VEGF, corticosteroids, or both treatments) in the full population.

CONCLUSIONS

In Portuguese practice, data showed that pre-FAc implantation, some patients did not respond to SOC treatment and/or they were undertreated. Following FAc implant administration, there were rapid, sustained, long-term visual and anatomical improvements, and a marked reduction in treatment burden.

Anti-angiogenic and antioxidant effects of axitinib in human retinal endothelial cells: implications in diabetic retinopathy

Diabetic retinopathy is a secondary microvascular complication of diabetes mellitus. This disease progresses from two stages, non-proliferative and proliferative diabetic retinopathy, the latter characterized by retinal abnormal angiogenesis. Pharmacological management of retinal angiogenesis employs expensive and invasive intravitreal injections of biologic drugs (anti-vascular endothelial growth factor agents). To search small molecules able to act as anti-angiogenic agents, we focused our study on axitinib, which is a tyrosine kinase inhibitor and represents the second line treatment for renal cell carcinoma. Axitinib is an inhibitor of vascular endothelial growth factor receptors, and among the others tyrosine kinase inhibitors (sunitinib and sorafenib) is the most selective towards vascular endothelial growth factor receptors 1 and 2. Besides the well-known anti-angiogenic and immune-modulatory functions, we hereby explored the polypharmacological profile of axitinib, through a bioinformatic/molecular modeling approach and in vitro models of diabetic retinopathy. We showed the anti-angiogenic activity of axitinib in two different in vitro models of diabetic retinopathy, by challenging retinal endothelial cells with high glucose concentration (fluctuating and non-fluctuating). We found that axitinib, along with inhibition of vascular endothelial growth factor receptors 1 (1.82 ± 0.10; 0.54 ± 0.13, phosphorylated protein levels in fluctuating high glucose vs . axitinib 1 µM, respectively) and vascular endothelial growth factor receptors 2 (2.38 ± 0.21; 0.98 ± 0.20, phosphorylated protein levels in fluctuating high glucose vs . axitinib 1 µM, respectively), was able to significantly reduce (p < 0.05) the expression of Nrf2 (1.43 ± 0.04; 0.85 ± 0.01, protein levels in fluctuating high glucose vs . axitinib 1 µM, respectively) in retinal endothelial cells exposed to high glucose, through predicted Keap1 interaction and activation of melanocortin receptor 1. Furthermore, axitinib treatment significantly (p < 0.05) decreased reactive oxygen species production (0.90 ± 0.10; 0.44 ± 0.06, fluorescence units in high glucose vs . axitinib 1 µM, respectively) and inhibited ERK pathway (1.64 ± 0.09; 0.73 ± 0.06, phosphorylated protein levels in fluctuating high glucose vs . axitinib 1 µM, respectively) in HRECs exposed to high glucose. The obtained results about the emerging polypharmacological profile support the hypothesis that axitinib could be a valid candidate to handle diabetic retinopathy, with ancillary mechanisms of action.

The Treatment of Diabetic Retinal Edema with Intravitreal Steroids: How and When

Diabetic macular edema (DME) is a common complication of diabetes mellitus and a leading cause of visual impairment worldwide. It is defined as the diabetes-related accumulation of fluid, proteins, and lipids, with retinal thickening, within the macular area. DME affects a significant proportion of individuals with diabetes, with the prevalence increasing with disease duration and severity. It is estimated that approximately 25-30% of diabetic patients will develop DME during their lifetime. Poor glycemic control, hypertension, hyperlipidemia, diabetes duration, and genetic predisposition are recognized as risk factors for the development and progression of DME. Although the exact pathophysiology is still not completely understood, it has been demonstrated that chronic hyperglycemia triggers a cascade of biochemical processes, including increased oxidative stress, inflammation, activation of vascular endothelial growth factor (VEGF), cellular dysfunction, and apoptosis, with breakdown of the blood-retinal barriers and fluid accumulation within the macular area. Early diagnosis and appropriate management of DME are crucial for improving visual outcomes. Although the control of systemic risk factors still remains the most important strategy in DME treatment, intravitreal pharmacotherapy with anti-VEGF molecules or steroids is currently considered the first-line approach in DME patients, whereas macular laser photocoagulation and pars plana vitrectomy may be useful in selected cases. Available intravitreal steroids, including triamcinolone acetonide injections and dexamethasone and fluocinolone acetonide implants, exert their therapeutic effect by reducing inflammation, inhibiting VEGF expression, stabilizing the blood-retinal barrier and thus reducing vascular permeability. They have been demonstrated to be effective in reducing macular edema and improving visual outcomes in DME patients but are associated with a high risk of intraocular pressure elevation and cataract development, so their use requires an accurate patient selection. This manuscript aims to provide a comprehensive overview of the pathology, epidemiology, risk factors, physiopathology, clinical features, treatment mechanisms of actions, treatment options, prognosis, and ongoing clinical studies related to the treatment of DME, with particular consideration of intravitreal steroids therapy.

Microvascular Changes after Epiretinal Membrane Vitrectomy with Intraoperative Intravitreal Dexamethasone Implant: An OCT Angiography Analysis

BACKGROUND

We aimed to explore microvascular changes evaluated with optical coherence tomography angiography (OCTA) in patients undergoing epiretinal membrane (ERM) pars-plana vitrectomy (PPV) combined with intravitreal Ozurdex implantation, compared with standard PPV. (2) Methods: Prospective interventional analysis on 25 eyes undergoing PPV + Ozurdex (Group A) and 25 eyes undergoing PPV alone. Best corrected visual acuity (BCVA) and OCTA parameters, such as vessel density (VD) of the superficial and deep capillary plexi (SCP and DCP) in the whole 6.4 mm × 6.4 mm and fovea area, were evaluated preoperatively and 3 months after surgery. (3) Results: Postoperative BCVA significantly improved in both groups. No cases of post-operative cystoid macular edema (CME) were reported in Group A vs. two eyes in Group B. In Group A we found a statistically significant increase of SCP's VD in either the whole image (from 42.1 ± 4.1 to 45.6 ± 4.3%, p = 0.01) and the fovea image (from 38.5 ± 7.5 to 41.7 ± 4.2%, p = 0.03). In Group B, we reported no significant variations in the SCP's VDs. In the DCP, VD significantly increased only in the whole image in Group A. Stage 4 ERMs showed the greatest improvement in VD, especially in Group A. (4) Conclusions: Intraoperative Ozurdex prompted a significant BCVA recovery and limited the occurrence of postoperative CME compared to the standard procedure. Moreover, Ozurdex implant is associated with a better restoration of microvascular structure in SCP and DCP.

Hyperglycemia-induced miR182-5p drives glycolytic and angiogenic response in Proliferative Diabetic Retinopathy and RPE cells via depleting FoxO1

PURPOSE

Diabetic Retinopathy (DR) is associated with metabolic dysfunction in cells such as retinal pigmented epithelium (RPE). Small molecular weight microRNAs can simultaneously regulate multiple gene products thus having pivotal roles in disease pathogenesis. Since miR182-5p is involved in regulating glycolysis and angiogenesis, two pathologic processes of DR, we investigated its status in DR eyes and in high glucose model in vitro.

METHOD

ology: Total RNA was extracted from vitreous humor of PDR (n = 48) and macular hole (n = 22) subjects followed by quantification of miR182-5p and its target genes. ARPE-19 cells, cultured in DMEM under differential glucose conditions (5 mM and 25 mM) were used for metabolic and biochemical assays. Cells were transfected with miRNA182 mimic or antagomir to evaluate the gain and loss of function effects.

RESULTS

PDR patient eyes had high levels of miR182-5p levels (p < 0.05). RPE cells under high glucose stress elevated miR182-5p expression with altered glycolytic pathway drivers such as HK2, PFKP and PKM2 over extended durations. Additionally, RPE cells under high glucose conditions exhibited reduced FoxO1 and enhanced Akt activation. RPE cells transfected with miR182-5p mimic phenocopied the enhanced basal and compensatory glycolytic rates observed under high glucose conditions with increased VEGF secretion. Conversely, inhibiting miR182-5p reduced Akt activation, glycolytic pathway proteins, and VEGF while stabilizing FoxO1.

CONCLUSION

Glycolysis-associated proteins downstream of the FoxO1-Akt axis were regulated by miR182-5p. Further, miR182-5p increased expression of VEGFR2 and VEGF levels, likely via inhibition of ZNF24. Thus, the FoxO1-Akt-glycolysis/VEGF pathway driving metabolic dysfunction with concurrent angiogenic signaling in PDR may be potentially targeted for treatment via miR182-5p modulation.

Safety and Efficacy of Dexamethasone Intravitreal Implant Given Either First-Line or Second-Line in Diabetic Macular Edema

Diabetic macular edema (DME) is a common sight-threatening complication of diabetic retinopathy (DR) and the leading cause of severe visual impairment among the working-age population. Several therapeutic options are available for the management of DME, including intravitreal corticosteroids. They have been traditionally used as second-line treatment, due to the risk of intraocular pressure increase and cataract-related adverse events. However, attention has recently been focused on the primary or early use of intravitreal corticosteroids, due to growing evidence of the crucial role of inflammation in the pathogenesis of DME. Furthermore, intravitreal steroid implants offer the additional advantage of a longer duration of action compared to anti-vascular endothelial growth factor agents (anti-VEGF). This review aims to summarize the available evidence on the efficacy and safety profile of dexamethasone (DEX) intravitreal implant, with a specific focus on clinical scenarios in which it might be considered or even preferred as first-line treatment option by adequate selection of patients, considering both advantages and possible adverse events. Patients with contraindications to anti-VEGF, DME with high inflammatory OCT biomarkers, pseudophakic patients and phakic patients' candidates to cataract surgery as well as vitrectomized eyes may all benefit from first-line DEX implant. Additionally, DME not responders to anti-VEGF should be considered for a switch to DEX implant and a combination therapy of DEX implant and anti-VEGF could be a valid option in severe and persistent DME.

Association of trabecular meshwork height with steroid-induced ocular hypertension

It is important to identify at-risk patients prior to administering steroid injections to prevent avoidable irreversible blindness inducted by steroid-induced ocular hypertension (SIOH). We aimed to investigate the association of SIOH following intravitreal dexamethasone implantation (OZURDEX) using anterior segment optical coherence tomography (AS-OCT). We conducted a retrospective case control study to assess the association between trabecular meshwork and SIOH. A total of 102 eyes that underwent both AS-OCT and intravitreal dexamethasone implant injection were divided into the post-steroid ocular hypertension and normal intraocular pressure groups. Ocular parameters that can contribute to intraocular pressure were measured using AS-OCT. Univariable logistic regression analysis was used to calculate the odds ratio of the SIOH and significant variables were further analyzed using a multivariable model. Trabecular meshwork (TM) height was significantly shorter in the ocular hypertension group (716.13 ± 80.55 μm) than that in the normal intraocular pressure group (784.27 ± 82.33 μm) (p < 0.001). The receiver operating characteristic curve technique analysis showed that the optimal cut-off of ≥ 802.13 μm for TM height specificity was 96.2%, and TM height with < 646.75 μm had a sensitivity of 94.70%. The odds ratio of the association was 0.990 (p = 0.001). TM height was identified as a newly observed association with SIOH. TM height can be assessed using AS-OCT, with acceptable sensitivity and specificity. Caution must be exercised while injecting steroids in patients with short TM height (especially < 646.75 μm) as it may cause SIOH and irreversible blindness.

Current Treatments for Diabetic Macular Edema

Diabetic retinopathy is a major retinal disorder and a leading cause of blindness. Diabetic macular edema (DME) is an ocular complication in patients with diabetes, and it can impair vision significantly. DME is a disorder of the neurovascular system, and it causes obstructions of the retinal capillaries, damage of the blood vessels, and hyperpermeability due to the expression and action of vascular endothelial growth factor (VEGF). These changes result in hemorrhages and leakages of the serous components of blood that result in failures of the neurovascular units (NVUs). Persistent edema of the retina around the macula causes damage to the neural cells that constitute the NVUs resulting in diabetic neuropathy of the retina and a reduction in vision quality. The macular edema and NVU disorders can be monitored by optical coherence tomography (OCT). Neuronal cell death and axonal degeneration are irreversible, and their development can result in permanent visual loss. Treating the edema before these changes are detected in the OCT images is necessary for neuroprotection and maintenance of good vision. This review describes the effective treatments for the macular edema that are therefore neuroprotective.

The 0.19-mg Fluocinolone Acetonide Intravitreal Implant Reduces Treatment Burden in Diabetic Macular Edema

PURPOSE

To assess treatment burden in patients with diabetic macular edema (DME) after the 0.19-mg fluocinolone acetonide (FAc) intravitreal implant (ILUVIEN).

DESIGN

Prospective and retrospective analyses of a 36-month, phase 4, open-label, observational study.

METHODS

Setting: Multicenter.

PATIENT POPULATION

Included patients had DME and previously received corticosteroid treatment without a clinically significant rise in intraocular pressure (IOP) (N = 202 eyes in 159 patients). Patients were not randomized.

OBSERVATION PROCEDURES

Prospective, observational treatment burden data were analyzed for their relationship to safety and functional efficacy outcomes across 36 months.

MAIN OUTCOME MEASURES

Outcomes included the mean number of yearly treatments, supplemental-free probability over time, best-corrected visual acuity, and monitoring of IOP-related events.

RESULTS

Over 36 months, the mean number of yearly treatments decreased from 3.5 before FAc to 1.7 after FAc; at 36 months, 68.3% of patients required 0 to 2 treatments per year. After FAc, the percentage of eyes requiring supplemental therapy decreased vs before FAc (P < .0001 for each). Through 36 months, 25% of FAc-treated eyes did not require supplemental treatment. At 36 months, mean best-corrected visual acuity increased by 4.5 letters vs a decline of 6.4 letters in the 36 months before FAc. IOP elevations >25 mm Hg occurred in 18.2% of eyes that did not receive supplemental treatment after FAc vs 27.2% of eyes that received supplemental treatments, which included additional intraocular steroids.

CONCLUSIONS

Over 36 months, the FAc implant is associated with improved visual outcomes and better disease control as measured by a significant reduction in yearly treatment burden in patients with DME.

Systemic Outcomes of Intravitreal Injections of Dexamethasone and Anti-Vascular Endothelial Growth Factor

INTRODUCTION

Intravitreal dexamethasone and anti-vascular endothelial growth factor (anti-VEGF) medications have revolutionized ocular disease management and favorable ocular safety profiles, but few studies have compared their systemic adverse events (SAEs). This study investigated the SAEs of intravitreal dexamethasone and anti-VEGFs by using real-world data.

METHODS

This retrospective cohort study sourced medical records from the largest multi-institutional database in Taiwan. Patients who received intravitreal dexamethasone (n = 137) or anti-VEGFs (n = 10,345) between 2014 and 2019 were enrolled. Propensity score matching was performed to achieve homogeneity between the two groups. Subdistribution hazard ratios (SHRs) and 95% confidence intervals (CIs) were calculated using the Fine-Gray model. Systemic as well as ocular clinical events and systemic biomarkers after 1-year follow-up were compared.

RESULTS

Both groups demonstrated comparable risks of major cardiac adverse events (SHR 1.57, 95% CI 0.29-8.55), heart failure (SHR 0.62, 95% CI 0.07-5.33), major bleeding (SHR 0.23, 95% CI 0.03-1.77), all-cause admission (SHR 0.73, 95% CI 0.41-1.30), and all-cause death (SHR 2.11, 95% CI 0.35-12.71). There were no significant differences in longitudinal changes in systolic and diastolic blood pressure, glycated hemoglobin, low-density lipoprotein, estimated glomerular filtration rate, or alanine aminotransferase between the groups. Both groups had a similar incidence of cataract surgery. Although the dexamethasone group exhibited a relatively high prevalence of antiglaucomatous medication use, there was not a significantly higher incidence of glaucoma surgery.

CONCLUSION

Intravitreal dexamethasone and anti-VEGF medications had comparable systemic safety profiles in our study. Both drugs represent efficacious and safe therapies for ocular diseases.

Intravitreal Dexamethasone Implant at the Time of Silicon Oil Removal to Treat Persistent Macular Edema after Rhegmatogenous Retinal Detachment Repair

BACKGROUND

An intravitreal dexamethasone implant (DEX-I) was found to be effective and safe for the treatment of cystoid macular edema (CME) after vitrectomy for rhegmatogenous retinal detachment (RRD) and in silicone oil (SO)-filled eyes. We aimed to investigate the efficacy and safety of DEX-I at the time of SO removal for the treatment of recalcitrant CME after successful RRD repair.

METHODS

A retrospective review of the medical records was performed on 24 consecutive patients (24 eyes) with recalcitrant CME after RRD repair who were treated with a single 0.7-mg DEX-I at the time of SO removal. The main outcome measures were changes in best-corrected visual acuity (BCVA) and central macular thickness (CMT). A regression model was performed to assess the relationship between BCVA and CMT at 6 months and independent variables.

RESULTS

In all 24 patients, CME occurred after RRD repair and remained despite topical therapy. The mean time of CME onset was 27.4 ± 7.7 days after vitrectomy. The mean time between vitrectomy and DEX-I was 106.8 ± 10.1 days. The mean CMT was significantly decreased from 429.6 ± 59.1 µm at baseline to 294 ± 46.4 µm at month 6 (p < 0.0001). The mean BCVA significantly improved from 0.99 ± 0.3 at baseline to 0.60 ± 0.3 at month 6 (p < 0.0001). An elevation of intraocular pressure was observed in one (4.1%) eye, which was medically managed. A univariate regression model revealed a relationship between month-6 BCVA after DEX-I and gender (β = -0.27; p = 0.03) and macular status (β = -0.45; p = 0.001) when RRD occurred. No relationship between month-6 CMT and independent variables was found.

CONCLUSIONS

DEX-I at the time of SO removal had an acceptable safety profile and achieved favorable outcomes in eyes affected by recalcitrant CME that occurred after RRD repair. RRD-related macular status is significantly associated with visual acuity after DEX-I.

Flavoprotein fluorescence elevation is a marker of mitochondrial oxidative stress in patients with retinal disease

Purpose

Recent studies of glaucoma, age-related macular degeneration, and diabetic retinopathy have demonstrated that flavoprotein fluorescence (FPF) can be utilized non-invasively as an indicator of mitochondrial oxidative stress in the retina. However, a comprehensive assessment of the validity and reliability of FPF in differentiating between healthy and diseased eyes across multiple disease states is lacking. Here, we evaluate the sensitivity and specificity of FPF in discriminating between healthy and diseased eyes in four leading causes of visual impairment worldwide, one of which has not been previously evaluated using FPF. We also evaluate the association between FPF and visual acuity.

Methods

A total of 88 eyes [21 eyes of 21 unaffected controls, 20 eyes from 20 retinal vein occlusion (RVO) patients, 20 eyes from 20 diabetic retinopathy (DR) patients, 17 eyes from 17 chronic exudative age-related macular degeneration (exudative AMD) patients, and 10 eyes from 10 central serous retinopathy (CSR) patients] were included in the present cross-sectional observational study. Eyes were imaged non-invasively using a specially configured fundus camera OcuMet Beacon® (OcuSciences, Ann Arbor, MI). The macula was illuminated using a narrow bandwidth blue light (455 - 470 nm) and fluorescence was recorded using a narrow notch filter to match the peak emission of flavoproteins from 520 to 540 nm. AUROC analysis was used to determine the sensitivity of FPF in discriminating between diseased eyes and healthy eyes. Nonparametric Kruskal-Wallis Tests with post-hoc Mann Whitney U tests with the Holm-Bonferroni correction were performed to assess differences in FPF intensity, FPF heterogeneity, and best corrected visual acuity (BCVA) between the five groups. Spearman rank correlation coefficients were calculated to assess the relationship between FPF and BCVA.

Results

AUROC analysis indicated that FPF intensity is highly sensitive for detecting disease, particularly for exudative AMD subjects (0.989; 95% CI = 0.963 - 1.000, p=3.0 x 107). A significant difference was detected between the FPF intensity, FPF heterogeneity, and BCVA in all four disease states compared to unaffected controls (Kruskal-Wallis Tests, p = 1.06 x 10-8, p = 0.002, p = 5.54 x 10-8, respectively). Compared to healthy controls, FPF intensity values were significantly higher in RVO, DR, exudative AMD, and CSR (p < 0.001, p < 0.001, p < 0.001, and p = 0.001, respectively). Spearman rank correlation coefficient between FPF intensity and BCVA was ρ = 0.595 (p = 9.62 x 10-10).

Conclusions

Despite variations in structural retinal findings, FPF was found to be highly sensitive for detecting retinal disease. Significant FPF elevation were seen in all four disease states, with the exudative AMD patients exhibiting the highest FPF values compared to DR, CSR, and RVO subjects. This is consistent with the hypothesis that there is elevated oxidative stress in all of these conditions as previously demonstrated by blood studies. FPF intensity is moderately correlated with the late-in disease-marker BCVA, which suggests that the degree of FPF elevation can be used as a metabolic indicator of disease severity.

Dexamethasone intravitreal implant in treatment-naïve diabetic macular oedema: findings from the prospective, multicentre, AUSSIEDEX study

AIM

To evaluate the effectiveness of dexamethasone intravitreal implant 0.7 mg (DEX; Ozurdex) monotherapy in the patient subgroup of the AUSSIEDEX study with treatment-naïve diabetic macular oedema (DME).

METHODS

The open-label, prospective, phase 4, real-world study included pseudophakic eyes and phakic eyes scheduled for cataract surgery that were treatment-naïve or non-responsive to antivascular endothelial growth factors. No eyes were excluded based on baseline best-corrected visual acuity (BCVA) or central subfield retinal thickness (CRT). After the initial DEX injection at the baseline visit, reinjection was permitted at ≥16-week intervals. Week-16 and week-52 visits were mandatory. Primary endpoints were changes in mean BCVA and CRT from baseline to 52 weeks.

RESULTS

Of 200 eyes enrolled in the AUSSIEDEX study, 57 were treatment-naïve. Baseline mean BCVA was 58.8 letters and baseline mean CRT was 418.6 µm; changes in mean BCVA and CRT from baseline to 52 weeks in this subgroup were 3.4 letters (p=0.042) and -89.6 µm (p<0.001), respectively, with a mean 2.5 injections. The change in mean CRT from baseline was -55.8 µm at week 16 (p<0.001). The most common adverse event was increased intraocular pressure (IOP), with 20.0% of eyes requiring IOP-lowering medication. One patient was discontinued due to increased IOP. No eyes required filtration surgery. No serious, treatment-related ocular adverse events were reported.

CONCLUSION

In this largest prospective, real-world study of DEX monotherapy for DME to date, DEX significantly improved CRT and BCVA at 52 weeks in treatment-naïve eyes, without new safety concerns, supporting DEX use in treatment-naïve DME.

TRIAL REGISTRATION NUMBER

NCT02731911.

Novel therapies for proliferative retinopathies

Proliferative retinopathies, such as neovascular age-related macular degeneration and proliferative diabetic retinopathy, are a special health issue due to their contribution to irreversible blindness. Although the promoting conditions and physiopathology of proliferative retinopathies are different, these feature a highly detrimental angiogenesis driven by the overproduction of vascular endothelial growth factor (VEGF). This article describes the mechanism of action of ocular antiangiogenic therapies currently found in clinical development. Systems classify accordingly as (a) novel anti-VEGF systems, (b) molecules targeting non-VEGF pathways, and (c) gene therapies. Whereas most therapies are designed to neutralize VEGF, there is a significant set of products with diverse complexity and mechanism of action. Anti-VEGF therapies are still the most studied approach to tackle angiogenesis. Therapies targeting non-VEGF pathways, however, are highlighted because they could be an option for patients nonresponsive to anti-VEGF therapies. Finally, gene therapy is a promissory technology platform but still is subject to demonstrate safety and efficacy.

The ghrelin-GHSR-1a pathway inhibits high glucose-induced retinal angiogenesis in vitro by alleviating endoplasmic reticulum stress

Background

To investigate the effect of ghrelin, a brain-gut peptide hormone, on high glucose-induced retinal angiogenesis in vitro and explore its association with endoplasmic reticulum (ER) stress.

Methods

Human retinal microvascular endothelial cells (HRMECs) were first divided into control and high-glucose groups, and the mRNA and protein expression levels of the receptor for ghrelin [growth hormone secretin receptor 1a, (GHSR-1a)] in cells were determined. HRMECs were then treated with high glucose alone or in combination with ghrelin or siGHSR-1a, and cell viability, migration, tube formation and the expression of the ER stress-related proteins PERK, ATF4 and CHOP were detected. Finally, to clarify whether the effects of ghrelin are related to ER stress, tunicamycin, an inducer of ER stress, was used to treat HRMECs, and cell viability, cell migration, and tube formation were evaluated.

Results

GHSR-1a expression in HRMECs at both the mRNA and protein levels was inhibited by high-glucose treatment. Under high-glucose conditions, ghrelin promoted cell viability and inhibited migration and tube formation, which were blocked by siGHSR-1a treatment. Ghrelin inhibited the increases in the protein levels of p-PERK, ATF4 and CHOP induced by high-glucose treatment, and combination treatment with siGHSR-1a reversed this effect of ghrelin. When tunicamycin was added, the effects of ghrelin on cell viability, migration and tube formation were all weakened.

Conclusions

This study experimentally revealed that ghrelin can inhibit high glucose-induced retinal angiogenesis in vitro through GHSR-1a, and alleviation of ER stress may be one of the mechanisms underlying this effect.

Management of Patients with Diabetic Macular Edema Switched from Dexamethasone Intravitreal Implant to Fluocinolone Acetonide Intravitreal Implant

To assess anatomical and functional outcomes after switching from dexamethasone implant (DEXi) to fluocinolone acetonide implant (FAci) in 113 diabetic macular edema eyes, a multicentric retrospective observational study was conducted. Seventy-five eyes (73.5%) were switched 1−8 weeks after their last DEXi. The mean best-corrected visual acuity improved to 59.8 letters at month 4 and remained stable during the follow-up. The mean central macular thickness (CMT) significantly decreased during the follow-up, with a minimum of 320.9 μm at month 3. The baseline CMT was higher in eyes that received the last DEXi >8 weeks versus <8 weeks before the first FAci (p < 0.021). After FAci injection, additional treatments were needed in 37 (32.7%) eyes. A longer diabetes duration (p = 0.009), a longer time between the last DEXi and the first FAci (p = 0.035), and a high baseline CMT (p = 0.003) were risk factors for additional treatments. The mean intraocular pressure was <19 mmHg at all timepoints, with no difference between eyes receiving the last DEXi ≤8 weeks or >8 weeks before the switch. Switching from DEXi to FAci in DME is effective and safe. A short time between the last DEXi and the first FAci reduced CMT fluctuations and the need for early additional treatments.

Describing Adverse Events Associated with Bilateral Same-Day Intravitreal Dexamethasone Implants

BACKGROUND AND OBJECTIVES

To explore the incidence of adverse events after bilateral same-day intravitreal 0.7-mg dexamethasone implant (SDIDI) injections.

MATERIALS AND METHODS

We performed an IRB approved, single-center, retrospective review of patients receiving bilateral SDIDI injections from January 1, 2016 to October 31, 2021 and reviewed adverse events that occurred within 3 months of injection.

RESULTS

A total of 206 bilateral (412 eyes) SDIDI injections were performed in 59 patients. Ocular hypertension or the addition of intraocular pressure (IOP) lowering drops occurred in 121 (29.4%) eyes after IDI. Two (0.5%) eyes required glaucoma drainage surgeries. Of the 117 phakic eyes, 32 (27.4%) had progression of cataract or cataract extraction. There were two (0.5%) episodes of vitreous hemorrhage and one (0.2%) retinal tear with retinal detachment. There were no cases of endophthalmitis.

CONCLUSION

Serious complication rates after bilateral same-day IDI injections appears low. Increased IOP that requires intervention can occur. [Ophthalmic Surg Lasers Imaging Retina 2022;53:612-618.].

Real-World Evidence in the Management of Diabetic Macular Edema with Intravitreal Anti-VEGFs in Asia: A Systematic Literature Review

Purpose

To evaluate the visual outcomes and safety profile of intravitreal anti-vascular endothelial growth factor (anti-VEGF) therapy in the treatment of diabetic macular edema (DME) in real-world studies in Asian countries.

Methods

A systematic review of electronic literature databases (Embase, Medline, and the Cochrane Library from January 1, 2010, to March 16, 2021) was conducted to identify observational studies that reported clinical and safety outcomes of anti-VEGF treatments for DME in Asia. We analyzed baseline patient characteristics, treatment patterns, mean number of injections, best-corrected visual acuity (BCVA), retinal thickness, and safety outcomes.

Results

Seventy-one studies were included in this review. Most studies reported treatment of DME with ranibizumab (n = 33), followed by aflibercept (n = 13), bevacizumab (n = 28), and conbercept (n = 9). At 12 months, the cumulative mean number of injections for ranibizumab, aflibercept, and conbercept was 5.2, 4.6, and 6, respectively. At the 12-month follow-up, the cumulative mean BCVA gain was 6.8 letters (ranibizumab), 4.6 letters (aflibercept), 4.9 letters (bevacizumab), and 8.3 letters (conbercept). The cumulative mean reduction in retinal thickness at 12 months was 116.9 μm (ranibizumab), 105.9 μm (aflibercept), 81.7 μm (bevacizumab), and 135.2 μm (conbercept). A strong positive correlation (r = 0.78) was observed between mean number of injections and change in BCVA at 12 months. A moderate positive correlation (r = 0.54) was observed between mean number of injections and mean reduction in retinal thickness at 12 months. A weak positive correlation was observed between baseline retinal thickness and visual acuity at 12 months. Baseline BCVA and mean number of injections were predictors of BCVA at 12 months.

Conclusion

All anti-VEGFs were effective in the treatment of DME in Asia. The data suggest that a greater number of anti-VEGF injections was associated with better improvement in BCVA and moderate reduction in retinal thickness at the 1-year follow-up.

Diabetic retinopathy: Involved cells, biomarkers, and treatments

Diabetic retinopathy (DR), a leading cause of vision loss and blindness worldwide, is caused by retinal neurovascular unit dysfunction, and its cellular pathology involves at least nine kinds of retinal cells, including photoreceptors, horizontal and bipolar cells, amacrine cells, retinal ganglion cells, glial cells (Müller cells, astrocytes, and microglia), endothelial cells, pericytes, and retinal pigment epithelial cells. Its mechanism is complicated and involves loss of cells, inflammatory factor production, neovascularization, and BRB impairment. However, the mechanism has not been completely elucidated. Drug treatment for DR has been gradually advancing recently. Research on potential drug targets relies upon clear information on pathogenesis and effective biomarkers. Therefore, we reviewed the recent literature on the cellular pathology and the diagnostic and prognostic biomarkers of DR in terms of blood, protein, and clinical and preclinical drug therapy (including synthesized molecules and natural molecules). This review may provide a theoretical basis for further DR research.

The Correlation Between MicroRNAs and Diabetic Retinopathy

Micro ribonucleic acids (miRNAs), as a category of post-transcriptional gene inhibitors, have a wide range of biological functions, are involved in many pathological processes, and are attractive therapeutic targets. Considerable evidence in ophthalmology indicates that miRNAs play an important role in diabetic retinopathy (DR), especially in inflammation, oxidative stress, and neurodegeneration. Targeting specific miRNAs for the treatment of DR has attracted much attention. This is a review focusing on the pathophysiological roles of miRNAs in DR, diabetic macular edema, and proliferative DR complex multifactorial retinal diseases, with particular emphasis on how miRNAs regulate complex molecular pathways and underlying pathomechanisms. Moreover, the future development potential and application limitations of therapy that targets specific miRNAs for DR are discussed.

Reciprocal Regulation between lncRNA ANRIL and p15 in Steroid-Induced Glaucoma

Steroid-induced glaucoma (SIG) is the most common adverse steroid-related effect on the eyes. SIG patients can suffer from trabecular meshwork (TM) dysfunction, intraocular pressure (IOP) elevation, and irreversible vision loss. Previous studies have mainly focused on the role of extracellular matrix turnover in TM dysfunction; however, whether the cellular effects of TM cells are involved in the pathogenesis of SIG remains unclear. Here, we found that the induction of cellular senescence was associated with TM dysfunction, causing SIG in cultured cells and mouse models. Especially, we established the transcriptome landscape in the TM tissue of SIG mice via microarray screening and identified ANRIL as the most differentially expressed long non-coding RNA, with a 5.4-fold change. The expression level of ANRIL was closely related to ocular manifestations (IOP elevation, cup/disc ratio, and retinal nerve fiber layer thickness). Furthermore, p15, the molecular target of ANRIL, was significantly upregulated in SIG and was correlated with ocular manifestations in an opposite direction to ANRIL. The reciprocal regulation between ANRIL and p15 was validated using luciferase reporter assay. Through depletion in cultured cells and a mouse model, ANRIL/p15 signaling was confirmed in cellular senescence via cyclin-dependent kinase activity and, subsequently, by phosphorylation of the retinoblastoma protein. ANRIL depletion imitated the SIG phenotype, most importantly IOP elevation. ANRIL depletion-induced IOP elevation in mice can be effectively suppressed by p15 depletion. Analyses of the single-cell atlas and transcriptome dynamics of human TM tissue showed that ANRIL/p15 expression is spatially enriched in human TM cells and is correlated with TM dysfunction. Moreover, ANRIL is colocalized with a GWAS risk variant (rs944800) of glaucoma, suggesting its potential role underlying genetic susceptibility of glaucoma. Together, our findings suggested that steroid treatment promoted cellular senescence, which caused TM dysfunction, IOP elevation, and irreversible vision loss. Molecular therapy targeting the ANRIL/p15 signal exerted a protective effect against steroid treatment and shed new light on glaucoma management.

Biomarkers as Predictive Factors of Anti-VEGF Response

Age-related macular degeneration is the main cause of irreversible vision in developed countries, and intravitreal anti-vascular endothelial growth factor (anti-VEGF) injections are the current gold standard treatment today. Although anti-VEGF treatment results in important improvements in the course of this disease, there is a considerable number of patients not responding to the standardized protocols. The knowledge of how a patient will respond or how frequently retreatment might be required would be vital in planning treatment schedules, saving both resource utilization and financial costs, but today, there is not an ideal biomarker to use as a predictive response to ranibizumab therapy. Whole blood and blood mononuclear cells are the samples most studied; however, few reports are available on other important biofluid samples for studying this disease, such as aqueous humor. Moreover, the great majority of studies carried out to date were focused on the search for SNPs in genes related to AMD risk factors, but miRNAs, proteomic and metabolomics studies have rarely been conducted in anti-VEGF-treated samples. Here, we propose that genomic, proteomic and/or metabolomic markers could be used not alone but in combination with other methods, such as specific clinic characteristics, to identify patients with a poor response to anti-VEGF treatment to establish patient-specific treatment plans.

Early Screening for Diabetic Retinopathy in Newly Diagnosed Type 2 Diabetes and Its Effectiveness in Terms of Morbidity and Clinical Treatment: A Nationwide Population-Based Cohort

PURPOSE

To characterize the association between the frequency of screening for diabetic retinopathy (DR) and the detection of DR in patients with newly diagnosed type 2 diabetes mellitus (T2DM).

METHODS

This nationwide population-based cohort study used data from the National Health Insurance Research Database to identify adult patients who were newly diagnosed with T2DM between 2000 and 2004. Data from their follow-up Diabetic retinopathy (DR) treatments over the next 10 years following diagnosis were also analyzed.

RESULTS

The 41,522 subjects were respectively assigned to a periodic screening group (n = 3850) and nonperiodic screening group (n = 37,672). Significant differences were observed between the two groups in terms of age, Charlson Comorbidity Index (CCI), sex, DR treatment, and the prevalence of DR. The association between periodic screening and DR treatment, only the elderly, female, and patient with severe CCI status showed the significance in the further stratified analysis.

CONCLUSION

Periodic screening (annual or biannual screening in the first 5 years) was more effective than nonperiodic screening in detecting instances of DR in the middle-to-advanced aged group but not among younger patients. Screening pattern did not have a significant effect on the likelihood of DR-related treatment during the 5-year follow-up. It appears that a tight screening schedule for the first 5 years after diagnosis with diabetes is not necessary.

MiR-192 attenuates high glucose-induced pyroptosis in retinal pigment epithelial cells via inflammasome modulation

Diabetic retinopathy is one of the most characteristic complications of diabetes mellitus, and pyroptosis plays acrucial role in the onset and development of diabetic retinopathy. Although microRNA-192 (miR-192) has been demonstrated to be involved in diabetic retinopathy progression, to the best of our knowledge, its potential and mechanism in cell pyroptosis in diabetic retinopathy have not been studied. The present study demonstrated that high glucose (HG) contributes to the pyroptosis of retinal pigment epithelial (RPE) cells in a dose-dependent manner. The results revealed that miR-192 was weakly expressed in HG-induced RPE cells. Furthermore, overexpression of miR-192 abrogated the role of HG in RPE cell pyroptosis. Based on the bioinformatics analysis, a dual-luciferase reporter assay, and an RNA pull-down assay, FTO α-ketoglutarate-dependent dioxygenase (FTO) was demonstrated to be a direct target of miR-192. Additionally, upregulation of FTO abolished the effects of miR-192 on RPE cells treated with HG. Nucleotide-binding domain leucine-rich repeat family protein 3 (NLRP3) inflammasome activation is vital for cell pyroptosis, and FTO functions as a pivotal modulator in the N⁶-methyladenosine modifications of various genes. Mechanistically, FTO enhanced NLRP3 expression by facilitating demethylation of NLRP3. In conclusion, the present results demonstrate that miR-192 represses RPE cell pyroptosis triggered by HG via regulation of the FTO/NLRP3 signaling pathway.

Efficacy and Safety of Subthreshold Micropulse Yellow Laser for Persistent Diabetic Macular Edema After Vitrectomy: A Pilot Study

Aim: To examine the effect of subthreshold micropulse yellow laser (SMYL) on best-corrected visual acuity (BCVA), central macular thickness (CMT), and optical coherence tomography angiography (OCT-A) changes in eyes with persistent diabetic macular edema (DME) after pars plana vitrectomy (PPV) for tractional DME (TDME).

Patients and Methods: In a comparative study, 95 eyes of 95 consecutive patients with persistent DME were prospectively enrolled. The SMYL group (54 eyes) was treated with SMYL 6 months after PPV, while the control group (41 eyes) was followed up without treatment. BCVA and CMT by OCT were analyzed at baseline and 3 and 6 months. Additionally, parameters such as the vessel density (VD) in the superficial capillary plexus (SCP) and deep capillary plexus (DCP), respectively, and the area of the foveal avascular zone (FAZ) were also evaluated on OCT-A.

Results: There were no significant differences between both groups in demographic data. In the SMYL group, mean BCVA was significantly increased [F(2,106) = 17.25; p &lt; 0.001; ηp2 = 0.246] from 51.54 ± 13.81 ETDRS letters at baseline to 57.81 ± 12.82 ETDRS letters at 3 months (p &lt; 0.001) and 57.83 ± 13.95 EDTRS letters at 6 months (p &lt; 0.001), respectively. In comparison to the control group, BCVA values were statistically significantly higher in the SMYL group at 3 and 6 months, respectively. Mean CMT significantly decreased [F(2,106) = 30.98; p &lt; 0.001; ηp2 = 0.368] from the baseline value 410.59 ± 129.91 μm to 323.50 ± 89.66 μm at 3 months (p &lt; 0.001) and to 283.39 ± 73.45 μm at 6 months (p &lt; 0.001). CMT values were significantly lower in the SMYL group (p &lt; 0.001), especially at 6 months follow-up time (p &lt; 0.001) compared with the control group. Parafoveal VD in the SCP and DCP was significantly higher in the SMYL group in comparison to the control group, respectively, at 3-month (SCP p &lt; 0.001; DCP p &lt; 0.001) and 6-month follow-up (SCP p &lt; 0.001; DCP p &lt; 0.001). FAZ area was also significantly smaller in the SMYL group at 6-month follow-up (p = 0.001). There were no adverse SMYL treatment effects.

Conclusion: SMYL therapy may be a safe and effective treatment option in eyes with persistent macular edema following PPV for TDME.

The Efficacy of Simultaneous Injection of Dexamethasone Implant and Ranibizumab Into Vitreous Cavity on Macular Edema Secondary to Central Retinal Vein Occlusion

The purpose of this study was to determine the safety and effectiveness of simultaneous vitreous injection of dexamethasone implant and ranibizumab on macular edema secondary to central retinal vein occlusion (CRVO). We conducted a 6-month retrospective self-control study. Twenty-five patients diagnosed with macular edema secondary to CRVO were enrolled in this study. The patients received intravitreal injection of dexamethasone implant and ranibizumab. The changes in best corrected visual acuity (BCVA), central retinal thickness (CRT) and interocular pressure (IOP) before and at 2w, 1, 2, 3, 4, 5, 6 m after injection were recorded and compared. The adverse reactions in eyes and whole body were observed. The BCVA of all patients at 2 w (61.8 ± 5.42), 1 m (68.68 ± 5.23), 2 m (70.8 ± 5.8), 3 m (68.44 ± 5.61), 4 m (65.76 ± 5.76), 5 m (67.08 ± 5.57), and 6 m (70.12 ± 5.46) after surgery were significantly higher than that before surgery (52.2 ± 5.06,p < 0.01), and CRT of all patients at 2w (393.36 ± 52.66 um), 1 m (334.52 ± 32.95 um), 2 m (298.800 ± 29.97 um), 3 m (309.080 ± 28.78 um), 4 m (345.48 ± 39.81 um), 5 m (349.080 ± 29.88 um), and 6 m (309.76 ± 30.41 um) after surgery were significantly reduced than that before surgery (583.76 ± 121.09 um, p < 0.01). Macular edema recurred in an average of 4.44 ± 0.51 months after treatment, and those patients received combined treatment again. During follow-up, the most common adverse reactions were subconjunctival hemorrhage and increased intraocular pressure, with the incidence of 22% (11/50) and 18% (9/50) respectively. In all cases, the increased intraocular pressure could be controlled by a single intraocular pressure reducing drug. No patient needed to receive anti-glaucoma surgery. The overall incidence of lens opacity was 4% (2/50). After the first injection, no case showed lens opacity. After re-injection, 2 patients (2 eyes) (8%) developed lens opacity. None of the patients showed serious ocular adverse reactions or systemic complications such as vitreous hemorrhage, retinal detachment, endophthalmitis, uveitis or ocular toxicity. The simultaneous vitreous injection of dexamethasone implant and ranibizumab can significantly improve the visual acuity and anatomical prognosis in macular edema secondary to central retinal vein occlusion (CRVO-ME) patients, exhibiting good safety and effectiveness.

Steroid Treatment in Macular Edema: A Bibliometric Study and Visualization Analysis

The use of steroids to treat macular edema (ME) is a research hotspot in ophthalmology. We utilized CiteSpace and VOSviewer software to evaluate the Web of Science Core Collection publications and to build visualizing maps to describe the research progress in this topic. There were 3,252 publications for three decades during 1988–2021. The number of studies was low during the first 14 years but has risen consistently in the following two decades. The average publications per year were only 4.8 during 1988–2002, which jumped to 113 per year during 2003–2012, and 227 per year during 2013–2021. These publications came from 83 countries/regions, with the United States, Germany, and Italy leading positions. Most studies were published in Investigative Ophthalmology Visual Science, and Ophthalmology was the most cited journal. We found 9,993 authors, with Bandello F having the most publications and Jonas JB being the most frequently co-cited. According to our research, the most popular keyword is triamcinolone acetonide (TA). Macular edema, diabetic macular edema (DME), retinal vein occlusion (RVO), dexamethasone (DEX), fluocinolone acetonide (FA), and some other keywords were commonly studied in this field. In conclusion, the bibliometric analysis provides a comprehensive overview of steroid hotspots and developmental tendencies in the macular edema study. While anti-VEGF therapy is the first-line treatment for DME and RVO-induced macular edema, steroids implant is a valid option for these DME patients not responding to anti-VEGF therapy and non-DME patients with macular edema. Combined therapy with anti-VEGF and steroid agents is vital for future research.

Relevance of Peptide Homeostasis in Metabolic Retinal Degenerative Disorders: Curative Potential in Genetically Modified Mice

The mammalian retina contains approximately 30 neuropeptides that are synthetized by different neuronal cell populations, glia, and the pigmented epithelium. The presence of these neuropeptides leaves a mark on normal retinal molecular processes and physiology, and they are also crucial in fighting various pathologies (e.g., diabetic retinopathy, ischemia, age-related pathologies, glaucoma) because of their protective abilities. Retinal pathologies of different origin (metabolic, genetic) are extensively investigated by genetically manipulated in vivo mouse models that help us gain a better understanding of the molecular background of these pathomechanisms. These models offer opportunities to manipulate gene expression in different cell types to help reveal their roles in the preservation of retinal health or identify malfunction during diseases. In order to assess the current status of transgenic technologies available, we have conducted a literature survey focused on retinal disorders of metabolic origin, zooming in on the role of retinal neuropeptides in diabetic retinopathy and ischemia. First, we identified those neuropeptides that are most relevant to retinal pathologies in humans and the two clinically most relevant models, mice and rats. Then we continued our analysis with metabolic disorders, examining neuropeptide-related pathways leading to systemic or cellular damage and rescue. Last but not least, we reviewed the available literature on genetically modified mouse strains to understand how the manipulation of a single element of any given pathway (e.g., signal molecules, receptors, intracellular signaling pathways) could lead either to the worsening of disease conditions or, more frequently, to substantial improvements in retinal health. Most attention was given to studies which reported successful intervention against specific disorders. For these experiments, a detailed evaluation will be given and the possible role of converging intracellular pathways will be discussed. Using these converging intracellular pathways, curative effects of peptides could potentially be utilized in fighting metabolic retinal disorders.

Runx1 regulates Tff1 expression to expedite viability of retinal microvascular endothelial cells in mice with diabetic retinopathy

Diabetic retinopathy (DR) represents a major complication of diabetes, and molecular mechanisms related to vascular dysfunction, particularly endothelial dysfunction, in DR remains unclear. In the present work, we generated a DR animal model using mice and a cell model in mouse retinal microvascular endothelial cells (mRMECs) to examine the role of Trefoil factor family 1 (Tff1) in DR. Tff1 was poorly expressed in DR mice and high glucose (HG)-treated mRMECs. Overexpression of Tff1 significantly attenuated streptozotocin-induced retinal proliferation and angiogenesis in DR mice and reduced the secretion of inflammatory factors. In HG-treated mRMECs, overexpression of Tff1 remarkably reduced the proliferation and angiogenesis of mRMECs. In further experiments, we found that Tff1 was transcriptionally repressed by Runt-related transcription factor 1 (Runx1) directly, and Tff1 expression was indirectly modulated by Runx1 via the core-binding factor subunit beta (CBF-β)/nuclear factor, erythroid 2/microRNA-423-5p axis and the CBF-β/estrogen receptor 1 (ESR1) axis. Moreover, Tff1 could inhibit the activation of NF-κB signaling pathway, which in turn attenuated retinal endothelial cell proliferation and angiogenesis. It was thus proposed that Runx1/Tff1/NF-κB axis may be a potential target for the treatment strategy of DR, and further studies are needed.

Caffeine Protects Against Retinal Inflammation

Caffeine, one of the most consumed central nervous system (CNS) stimulants, is an antagonist of A₁ and A_2A adenosine receptors. In this study, we investigated the potential protective effects of this methylxanthine in the retinal tissue. We tested caffeine by using in vitro and in vivo paradigms of retinal inflammation. Human retinal pigment epithelial cells (ARPE-19) were exposed to lipopolysaccharide (LPS) with or without caffeine. This latter was able to reduce the inflammatory response in ARPE-19 cells exposed to LPS, attenuating the release of IL-1β, IL-6, and TNF-α and the nuclear translocation of p-NFκB. Additionally, caffeine treatment restored the integrity of the ARPE-19 monolayer assessed by transepithelial electrical resistance (TEER) and the sodium fluorescein permeability test. Finally, the ischemia reperfusion (I/R) injury model was used in C57BL/6J mice to induce retinal inflammation and investigate the effects of caffeine treatment. Mouse eyes were treated topically with caffeine, and a pattern electroretinogram (PERG) was used to assess the retinal ganglion cell (RGC) function; furthermore, we evaluated the levels of IL-6 and BDNF in the retina. Retinal BDNF dropped significantly (p < 0.05) in the I/R group compared to the control group (normal mice); on the contrary, caffeine treatment maintained physiological levels of BDNF in the retina of I/R eyes. Caffeine was also able to reduce IL-6 mRNA levels in the retina of I/R eyes. In conclusion, these findings suggest that caffeine is a good candidate to counteract inflammation in retinal diseases.

Preventive Efficacy of an Antioxidant Compound on Blood Retinal Barrier Breakdown and Visual Dysfunction in Streptozotocin-Induced Diabetic Rats

In diabetic retinopathy (DR), high blood glucose drives chronic oxidative stress and inflammation that trigger alterations of the neurovascular balance finally resulting in vascular abnormalities and retinal cell death, which converge towards altered electroretinogram (ERG). In the last years, a growing body of preclinical evidence has suggested that nutrients with anti-inflammatory/antioxidant properties can be able to hamper DR progression since its very early stages. In the present study, we used a streptozotocin-induced rat model of DR, which mimics most aspects of the early stages of human DR, to test the preventive efficacy of a novel compound containing cyanidin-3-glucoside (C3G), verbascoside and zinc as nutrients with antioxidant and anti-inflammatory properties. Western blot, immunofluorescence and electroretinographic analyses demonstrated a dose-dependent inhibition of oxidative stress- and inflammation-related mechanisms, with a significant counterpart in preventing molecular mechanisms leading to DR-associated vasculopathy and its related retinal damage. Preventive efficacy of the compound on dysfunctional a- and b-waves was also demonstrated by electroretinography. The present demonstration that natural compounds, possibly as a consequence of vascular rescue following ameliorated oxidative stress and inflammation, may prevent the apoptotic cascade leading to ERG dysfunction, adds further relevance to the potential application of antioxidants as a preventive therapy to counteract DR progression.

Nanotechnology-based formulations to amplify intraocular bioavailability

Conventional drug delivery formulations, such as eye drops and ointments, are mainly administered by topical instillation. The topical delivery of ophthalmic drugs is a challenging endeavor despite the eye is easily accessible. Unique and complex barriers, serving as protection against extrinsic harmful factors, hamper therapeutic intraocular drug concentrations. Bioavailability for deeper ocular tissues of the anterior segment of the eye is exceptionally low. As the bioavailability of the active substance is the major hurdle to overcome, dosing is increased, so the side effects do. Both provoke patient poor compliance, confining the desired therapeutic outcome. The incidence and severity of adverse reactions amplify evenly in the case of chronic treatments. Current research focuses on the development of innovative delivery strategies to address low ocular bioavailability and provide safe and convenient dosing schemes. The main objective of this review is to explore and present the latest developments in ocular drug delivery formulations for the treatment of the pathology of the anterior segment of the eye. Nanotechnology-based formulations, that is, organic nanoparticles (liposomes, niosomes/discosomes, dendrimers, nanoemulsions, nanosuspensions, nanoparticles/nanospheres) and inorganic nanoparticles, nanoparticle-laden therapeutic contact lenses, in situ gelling systems, and ocular inserts, are summarized and presented accordingly.

Impact of Injection Protocol Selection by Retina Specialists on Clinical Outcomes in Patients with Diabetic Macular Edema

Intravitreal anti-VEGF injections are the current gold standard for treating diabetic macular edema (DME). However, injection practice patterns of retina specialists have varied markedly based on physician discretion. This retrospective study analyzes the impact of injection protocol selection on change in best-corrected visual acuity (BCVA) and central macular thickness (CMT) in 170 eyes treated by 4 retina specialists practicing a pro re nata (PRN) strategy between 2010 and 2020. DME patients received an average of 7.25 injections every 6.24 weeks over 56.6 weeks. There were significant differences between retina specialists in mean number of injections (p = 0.0001) and mean length of treatment (p = 0.0007) but not in mean interval between injections. Over the treatment period, average change in BCVA was −0.053 logMAR, and average change in CMT was −51.1 µm, neither of which had significant differences between retina specialists. BCVA and CMT at initial visit were found to be significantly associated with improved BCVA and CMT over the treatment period (p < 0.001). Number of injections administered and interval between injections were not found to be significant factors affecting change in BCVA or CMT. Despite significant differences in injection dosing regimen, retina specialists achieved similar outcomes in change in BCVA and CMT over the treatment period.

Cost-effectiveness of dexamethasone and triamcinolone for the treatment of diabetic macular oedema in Finland: A Markov-model

PURPOSE

Diabetic macular oedema (DMO), a complication of diabetes, causes vision loss and blindness. Corticosteroids are usually used as a second-line treatment. The aim of this study was to analyse the cost-effectiveness of dexamethasone implants compared to cheaper and more frequently applied triamcinolone injections.

METHODS

Markov-modelling, which incorporated both eyes, was used for economic evaluation. The model consisted of five health states based on visual acuity, illustrating the progression of DMO. A cycle length of five months was chosen for dexamethasone and four months for triamcinolone. Time horizons of two and five years were applied. Transition probabilities and health state utilities were sourced from previous studies. The perspective used in this analysis was the hospital perspective. The health care costs were acquired from Kuopio University Hospital in Finland.

RESULTS

In this cost-effectiveness analysis, the incremental cost-effectiveness ratio ICER with 3% discount rate was €56 591/QALY for a two-year follow-up and -€1 110 942/QALY for a five-year follow-up. In order to consider dexamethasone as cost-effective over a 2-year time horizon, the WTP needs to be around €55 000/QALY. Over the five-year follow-up, triamcinolone is clearly a dominant treatment. Sensitivity analyses support the cost-effectiveness of dexamethasone over a 2-year time horizon.

CONCLUSIONS

Since the sensitivity analyses support the results, dexamethasone would be a cost-effective treatment during the first two years with WTP threshold around €55 000/QALY, and triamcinolone would be a convenient treatment after that. This recommendation is in line with the guidelines of EURETINA.

Impact of Different Clinical Baseline Characteristics on Intravitreal Dexamethasone Implant Ozurdex® Outcomes

Purpose

To determine the impact of different baseline clinical characteristics on the improvement in best corrected visual acuity (BCVA) in patients with diabetic macular edema (DME) who underwent the intravitreal dexamethasone implant (DEX) Ozurdex^®.

Methods

This was a single center retrospective study conducted on patients with DME, either naïve or previously treated, who were treated with one or more DEX and had a follow-up of at least 6 months. The main outcome measure was the proportion of DEX achieving an improvement ≥15 letters in BCVA.

Results

The study analyzed 192 DEX implants administered to 97 eyes (65 patients). Among the 192 DEX analyzed, 57 (29.7%) implants achieved a BCVA improvement ≥15 letters (ETDRS) from baseline, with a mean time for achieving such improvement of 89.2 (39.7) days. Eyes who received an additional DEX and those with a duration of DME < 6 months had a greater probability of achieving a BCVA improvement ≥15 letters (odds-ratio: 2.55, p = 0.0028 and odds-ratio: 1.93, p = 0.0434). The mean (standard deviation) change in BCVA from baseline was 7.5 (14.5) letters, p < 0.0001. The mean change in central macular thickness (CMT) from baseline was -128.0 (151.0) µm, p < 0.0001. The mean number of DEX implanted was 1.9 (0.8). Four (2.1%) DEX experienced an intraocular pressure increased ≥10 mm Hg; all the cases were successfully managed with topical antiglaucoma medication.

Conclusion

The results of this study confirmed previous evidence suggesting that DEX is effective for improving BCVA and CMT in patients with DME.

Fingolimod and Diabetic Retinopathy: A Drug Repurposing Study

This study aimed to investigate the interactions between fingolimod, a sphingosine 1-phosphate receptor (S1PR) agonist, and melanocortin receptors 1 and 5 (MCR1, MCR5). In particular, we investigated the effects of fingolimod, a drug approved to treat relapsing-remitting multiple sclerosis, on retinal angiogenesis in a mouse model of diabetic retinopathy (DR). We showed, by a molecular modeling approach, that fingolimod can bind with good-predicted affinity to MC1R and MC5R. Thereafter, we investigated the fingolimod actions on retinal MC1Rs/MC5Rs in C57BL/6J mice. Diabetes was induced in C57BL/6J mice through streptozotocin injection. Diabetic and control C57BL/6J mice received fingolimod, by oral route, for 12 weeks and a monthly intravitreally injection of MC1R antagonist (AGRP), MC5R antagonist (PG20N), and the selective S1PR1 antagonist (Ex 26). Diabetic animals treated with fingolimod showed a decrease of retinal vascular endothelial growth factor A (VEGFA) and vascular endothelial growth factor receptors 1 and 2 (VEGFR1 and VEGFR2), compared to diabetic control group. Fingolimod co-treatment with MC1R and MC5R selective antagonists significantly (p < 0.05) increased retinal VEGFR1, VEGFR2, and VEGFA levels compared to mice treated with fingolimod alone. Diabetic animals treated with fingolimod plus Ex 26 (S1PR1 selective blocker) had VEGFR1, VEGFR2, and VEGFA levels between diabetic mice group and the group of diabetic mice treated with fingolimod alone. This vascular protective effect of fingolimod, through activation of MC1R and MC5R, was evidenced also by fluorescein angiography in mice. Finally, molecular dynamic simulations showed a strong similarity between fingolimod and the MC1R agonist BMS-470539. In conclusion, the anti-angiogenic activity exerted by fingolimod in DR seems to be mediated not only through S1P1R, but also by melanocortin receptors.

Au-O-MWCNTs and TiO2-O-MWCNTs as Efficient Nanocarriers for Dexamethasone: Adsorption Isotherms and Kinetic Studies

In this research, the fabrication of drug delivery systems based on oxidized multiwall carbon nanotubes (O-MWCNTs) was studied. Herein, TiO2 and Au were conjugated with O-MWCNTs to prepare efficient nanocarriers for dexamethasone (dex). The samples were characterized by Fourier transform infrared (FTIR), scanning electron microscopy (SEM), and X-ray diffraction (XRD). In addition, dex loading was studied using adsorption isotherms including Langmuir, Freundlich, Temkin, and Dubinin–Radushkevich. The results show that dex adsorption agreed well with the Freundlich isotherm. Increasing the TiO2 to O-MWCNT ratio from (1 : 4) to (1 : 2) can improve the adsorption capacity from $290\text{mg}\cdot {\text{g}}^{-1}$ to 320 $320\text{mg}\cdot {\text{g}}^{-1}$ . The increasing Au amount increases the adsorption capacity from $437.78\text{mg}\cdot {\text{g}}^{-1}$ (SA1) to maximum $476.19\text{mg}\cdot {\text{g}}^{-1}$ (SA6). The maximum equilibrium binding energy $A_T$ $\left(1.67\text{L}\cdot {\text{mg}}^{-1}\right)$ was obtained for SA2, and SA7 shows high binding strength between dex and the nanoadsorbent. Carbon nanotubes (CNTs) show good affinity with high loading capabilities for dexamethasone adsorption. The synthesized TiO2-O-MWCNTs:1/2 with the maximum removal percent (80%) was proposed as an appropriate nanocarrier for dexamethasone. Pseudo-first order, pseudo-second order, Elovich, and intraparticle diffusion models were investigated for all synthesized drug nanocarriers. According to regression coefficients, experimental data are in good agreement with the pseudo-second order model for all adsorbents except O-MWCNT/CTAB. Experimental results revealed that the Elovich model could account for the O-MWCNT/CTAB adsorbent.

Place of intravitreal dexamethasone implant in the treatment armamentarium of diabetic macular edema

Diabetic macular edema (DME) is a very important and well-known cause of visual loss in diabetics. Blood–retina barrier disruption and consequent intraretinal fluid accumulation may lead to retinal thickening at the posterior pole namely DME. Even though it is not clearly understood, current evidence suggests that chronic low-grade inflammation characterized with various cytokines has a major role in the occurrence of DME. Clinical trials are continuously shaping our treatment approaches for the eyes with DME. Today, vascular endothelial growth factor (VEGF) inhibitor and steroid administrations are the main alternatives in DME treatment. Dexamethasone (DEX) implant (Ozurdex^®; Allergan, Inc., Irvine, CA, United States) was approved by the United States Food & Drug Administration in 2014 for DME treatment. The implant is made up of a biodegradable solid copolymer that is broken down by releasing its active ingredient into the vitreous cavity over time. Biphasic release feature of this sustained-release drug delivery system ensures its efficacy for up to 6 mo with an acceptable and manageable safety profile. DEX implant provides a favorable anatomical and functional outcome in DME as shown in several randomized-controlled studies but has a relatively higher ocular side-effect profile such as increased risk of cataract formation and raised intraocular pressure when compared to the gold standard anti-VEGF agents. Thus, DEX implant becomes the second-line treatment option demonstrating inadequate clinical response to anti-VEGF therapy. However, it can be preferred as the first-line treatment in vitrectomized and pseudophakic eyes. Even in some selected conditions DEX implant is favored over anti-VEGF agents where the use of VEGF-inhibitors is either inappropriate or contraindicated such as the patients with a recent history of a major cardiovascular or cerebrovascular event, pregnancy and noncompliant to frequent visits. This mini-review briefly overviews the efficacy, safety profile and complications of DEX implant and summarizes the outcome of DEX implant administration in major clinical studies on DME treatment.

Attenuation of High Glucose-Induced Damage in RPE Cells through p38 MAPK Signaling Pathway Inhibition

This study aimed to investigate the high glucose damage on human retinal pigment epithelial (RPE) cells, the role of p38 MAPK signaling pathway and how dimethyl fumarate can regulate that. We carried out in vitro studies on ARPE-19 cells exposed to physiological and high glucose (HG) conditions, to evaluate the effects of DMF on cell viability, apoptosis, and expression of inflammatory and angiogenic biomarkers such as COX-2, iNOS, IL-1β, and VEGF. Our data have demonstrated that DMF treatment attenuated HG-induced apoptosis, as confirmed by reduction of BAX/Bcl-2 ratio. Furthermore, in RPE cells exposed to HG we observed a significant increase of iNOS, COX-2, and IL-1β expression, that was reverted by DMF treatment. Moreover, DMF reduced the VEGF levels elicited by HG, inhibiting p38 MAPK signaling pathway. The present study demonstrated that DMF provides a remarkable protection against high glucose-induced damage in RPE cells through p38 MAPK inhibition and the subsequent down-regulation of VEGF levels, suggesting that DMF is a small molecule that represents a good candidate for diabetic retinopathy treatment and warrants further in vivo and clinical evaluation.