Diabetic macular edema: new concepts in patho-physiology and treatment

The Optimization of an Anti-VEGF Therapeutic Regimen for Neovascular Glaucoma

This study investigates the safety and efficacy of conbercept injection through different routes for neovascular glaucoma (NVG) treatment, in which seventy-four patients (81 eyes) with NVG caused by ischemia retinopathy had participated. Patients were divided into three stages according to the progression of NVG and were randomly assigned to receive intracameral or intravitreal conbercept injection. After conbercept injection, patients experienced improved best-corrected visual acuity (BCVA), good intraocular pressure (IOP) control, and neovascularization of Iris (NVI) regression. In stage III, patients required trabeculectomy with mitomycin C plus pan-retinal photocoagulation (PRP) to achieve complete NVI regression. Compared to the intravitreal group, the intracameral group had significantly lower IOP in 2 days in stage III and 1 day in stages I and II after injection, complete NVI regression before PRP in stages I and II, and better NVI regression in stage III. The rates of hyphema after trabeculectomy and malfunction filtering bleb suffering needle bleb revision were lower in the intracameral group, but only the hyphema rate was significantly different. Injections through different routes are all safe. We recommend intravitreal injections for patients in stages I and II, but for stage III, intracameral injection is better, and trabeculectomy with mitomycin C should be conducted within 2 days after injection to maximally reduce the risk of perioperative hyphema.

Trial Registration:ClinicalTrials.gov, identifier NCT03154892.

Vitreous microparticles contain apoptotic signals suggesting a diabetic vitreopathy

AIM

To evaluate differences in microparticle profiles in vitreous samples between diabetic and non-diabetic eyes undergoing vitrectomy.

METHODS

Un-masked cross-sectional series of 34 eyes undergoing vitrectomy. Vitreous specimens were collected and processed to evaluate for membrane integrity (DAPI), apoptosis (Annexin-V), and endothelial-cell origin (V-Cadherin). A BD LSR II flow cytometer was used for analysis and standardized sub-micron-sized beads were used for size comparison.

RESULTS

Thirty-four specimens underwent analysis. Greater levels of Annexin-V were found on microparticles from specimens in which blood had entered the vitreous (n=12) compared to those without blood (n=22; 52.3%±30.7% vs 19.6%±27.2%, P=0.002). Patients with diabetes having surgery with hemorrhage (n=7) had greater expression of Annexin-V than those without hemorrhage (n=8; 62.1%±31.7% vs 18.9%±20.9%, P=0.009). However, in patients with non-diabetic vitreous hemorrhage, the level of Annexin-V expression was not significantly different compared to other disease processes (38.6%±25.7%, n=5 vs 20.0%±30.9%, n=14, P=0.087).

CONCLUSION

Increased expression of the apoptotic marker, Annexin-V is detected on vitreous microparticles in diabetes-related vitreous hemorrhage. When evaluating vitreous hemorrhage in patients without diabetes, the apoptotic signal is not significantly different. Vitrectomy in patients with diabetes, and improvement in visual outcomes, may be related to the removal of a serum-derived, pro-apoptotic vitreous. Further investigation is warranted in order to identify the molecular characteristics of microparticles that regulate disease.

Associations Between Diabetic Retinal Microvasculopathy and Neuronal Degeneration Assessed by Swept-Source OCT and OCT Angiography

Purpose: To provide clinical evidence of the associations between retinal neuronal degeneration and microvasculopathy in diabetic retinopathy (DR). Methods: This case-control study included 76 patients (76 eyes) with type 2 diabetes mellitus (DM), and refraction error between -3.0 and +3.0 D. The eyes were assigned into DM (without DR), non-proliferative DR (NPDR), and proliferative DR (PDR) groups. Age-, sex-, and refractive error-matched normal subjects were enrolled as controls. The mean retinal thickness (mRT), the relative mean thickness of the retinal nerve fiber layer (rmtRNFL, mtRNFL/mRT), ganglion cell layer (rmtGCL), ganglion cell complex (rmtGCC) layer, foveal avascular zone area (FAZa), FAZ perimeter (FAZp), FAZ circularity index (FAZ-CI), and vessel density (VD) in superficial capillary plexus (SCP) and deep capillary plexus (DCP) were assessed by swept-source optical coherence tomography (OCT) and OCT angiography (OCTA). Group comparison and Spearman's partial correlation coefficient analysis were applied to evaluate the correlation between these morphological parameters. Results: rmtRNFL, FAZa, and FAZp in SCP and DCP increased with the DR severity (p _rmtRNFL < 0.001; p _{FAZa, SCP} = 0.001; p _FAZa , _DCP = 0.005; p _FAZp , _SCP < 0.001; p _FAZp , _DCP < 0.001). The rmtGCL, FAZ-CI in SCP and DCP, and VD in DCP decreased with the DR severity (p _rmtGCL = 0.002, p _FAZ-CI , _SCP = 0.002; p _{FAZ-CI, DCP} < 0.001, p _VD , _DCP < 0.001). After controlling age, sex, duration of diabetes, and hypertension, the rmtRNFL, FAZa in SCP and DCP, and FAZp in SCP and DCP were correlated with the severity of DR (p < 0.05), while VD in SCP and DCP, FAZ-CI, and rmtGCL were negatively correlated with the severity of DR (p < 0.05). The rmtGCL was negatively correlated with the FAZa in SCP (r = -0.34, p = 0.002) and DCP (r = -0.23, p = 0.033), and FAZp in SCP (r = -0.37, p = 0.001) and DCP (r = -0.32, p = 0.003), but positively correlated with VD in SCP (r = 0.26, p = 0.016), VD in DCP (r = 0.28, p = 0.012), and FAZ-CI in DCP (r = 0.31, p = 0.006). Conclusions: rmtRNFL, FAZ-CI in SCP and DCP, and FAZp in SCP are strong predictors of the severity of DR. The ganglion cell body loss is highly correlated with increased FAZp and FAZa, decreased FAZ-CI, and reduced VD with the severity of DR.

Intravitreal Tissue Plasminogen Activator Injection for Treatment-Resistant Diabetic Macular Edema of the Vitrectomized Eye

Diabetic macular edema (DME) is the main cause of visual loss in patients with diabetic retinopathy. DME has been treated using intravitreal anti-vascular endothelial growth factor (VEGF) drugs, steroids, laser photocoagulation, vitreoretinal surgery, and their combinations. These modalities are generally effective in preserving vision, but they sometimes produce only limited responses in patients with persistent or refractory DME. The levels of various inflammatory factors, including cytokines, chemokines, and extracellular matrices, as well as VEGF in the vitreous fluid, are increased in patients with DME. Excessive fibrinogen/fibrin levels in the vitreous fluid or fibrin deposition in the retina also contribute to DME pathogenesis. Tissue plasminogen activator (t-PA) promotes the degradation of fibrinogen or fibrin. Intravitreal t-PA injection is a commonly used treatment for subretinal hemorrhage secondary to age-related macular degeneration. Intravitreal t-PA injections have previously been used to restore vision by inducing posterior vitreous detachment in patients with DME. Herein, we describe the visual outcomes of intravitreal t-PA injection in a 78-year-old woman with treatment-resistant DME in her vitrectomized eye after several previous treatments. Before the injection, her best-corrected visual acuity (BCVA) was 0.7 logMAR and central foveal retinal thickness (CRT) was 735 μm. At 1 month after the injection, her BCVA was 0.8 logMAR and CRT was 558 μm, and 3 months later, her BCVA was 0.8 logMAR and CRT was 207 μm. Her BCVA was sustained, and CRT showed gradual improvements. These findings suggested the effectiveness of intravitreal t-PA injections for DME in the vitrectomized eye.

Histopathological assessments reveal retinal vascular changes, inflammation, and gliosis in patients with lethal COVID-19

Purpose

The purpose of this study is to assess for histopathological changes within the retina and the choroid and determine the long-term sequelae of the SARS-CoV-2 infection.

Methods

Eyes from seven COVID-19-positive and six similar age-matched control donors with a negative test for SARS-CoV-2 were assessed. Globes were evaluated ex vivo with macroscopic, SLO and OCT imaging. Macula and peripheral regions were processed for Epon embedding and immunocytochemistry.

Results

Fundus analysis shows hemorrhagic spots and increased vitreous debris in several of the COVID-19 eyes compared to the controls. OCT-based measurements indicated an increased trend in retinal thickness in the COVID-19 eyes; however, the difference was not statistically significant. Histology of the retina showed presence of hemorrhages and central cystoid degeneration in several of the donors. Whole mount analysis of the retina labeled with markers showed changes in retinal microvasculature, increased inflammation, and gliosis in the COVID-19 eyes compared to the controls. The choroidal vasculature displayed localized changes in density and signs of increased inflammation in the COVID-19 samples.

Conclusions

In situ analysis of the retinal tissue suggests that there are severe subclinical abnormalities that could be detected in the COVID-19 eyes. This study provides a rationale for evaluating the ocular physiology of patients that have recovered from COVID-19 infections to further understand the long-term effects caused by this virus.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00417-021-05460-1.

The Effect of Ranibizumab Loading Treatment on Vision-Related Quality of Life in Diabetic Macular Edema

AIMS

To investigate the changes in vision-related quality of life after a loading dose of three consecutive intravitreal ranibizumab (IVR) injections in patients with unilateral diabetic macular edema (DME).

MATERIALS AND METHODS

Fifty-two eyes of 52 patients who received IVR injections in only one eye with DME were included in our study. The following characteristics of the patients were recorded: gender, education status, marital status, work status, presence of chronic disease. The changes in best-corrected visual acuity (BCVA) and central macular thickness (CMT) were evaluated at baseline (before treatment) and 1 month after the third intravitreal injection (after treatment). Patients were administered the Turkish form of the National Eye Institute 25-Item Visual Functions Questionnaire (NEI VFQ-25 TR). The quality of life scores assessed by the NEI VFQ-25 TR, the BCVA, intraocular pressure (IOP), and CMT measurements were compared at baseline (before treatment) and 1 month after the third intravitreal injection (after treatment).

RESULTS

We enrolled 52 patients (25 females, 27 males) in our study; mean age was 64.35 ± 9.26 years. After treatment, BCVA improved significantly (p = 0.001), and macular thickness decreased significantly (p < 0.001). All NEI VFQ-25 TR subscale scores were significantly higher after treatment (p < 0.05). However, no significant correlation was found between the change in BCVA and CMT and the change in NEI VFQ-25 TR subscale and composite scores. The increase in near activities scores was significantly higher in males (p = 0.020) and in the retired group (p = 0.022). There were no significant differences in the changes in NEI VFQ-25 TR subscale and composite scores in relation to educational status.

DISCUSSION

Significant improvements in BCVA, macular edema, and vision-related quality of life were found in DME patients who received IVR injections with a loading dose, as shown by the NEI VFQ-25 TR. Interestingly, a significant improvement in quality of life was observed even though the patients could see well with the fellow eye. In conclusion, the NEI VFQ-25 TR is a useful scale to evaluate the changes in visual function and psychosocial characteristics of DME patients after treatment.

Recent Advancements in the Medical Treatment of Diabetic Retinal Disease

Diabetic retinal disease remains one of the most common complications of diabetes mellitus (DM) and a leading cause of preventable blindness. The mainstay of management involves glycemic control, intravitreal, and laser therapy. However, intravitreal therapy commonly requires frequent hospital visits and some patients fail to achieve a significant improvement in vision. Novel and long-acting therapies targeting a range of pathways are warranted, while evidence to support optimal combinations of treatments is currently insufficient. Improved understanding of the molecular pathways involved in pathogenesis is driving the development of therapeutic agents not only targeting visible microvascular disease and metabolic derangements, but also inflammation and accelerated retinal neurodegeneration. This review summarizes the current and emerging treatments of diabetic retinal diseases and provides an insight into the future of managing this important condition.

Comparison of multicolor scanning laser ophthalmoscopy and optical coherence tomography angiography for detection of microaneurysms in diabetic retinopathy

This study aimed to evaluate the usefulness of multicolor (MC) scanning laser ophthalmoscopy (MC-SLO) in detecting microaneurysm (MA) in eyes with diabetic retinopathy (DR). This was a retrospective cross-sectional study. Eyes with DR underwent fluorescein angiography (FA), MC-SLO, optical coherence tomography angiography (OCTA), and color fundus photography (CFP) were analyzed. The foveal region was cut in an 6 × 6 mm image and the number of MA in each image was counted by retina specialists to determine the sensitivity and positive predictive value. FA results were used as the ground standard. MAs were classified as those with early, late, or no dye leakage based on FA images. Fifty-four eyes of 35 patients with an average age of 64.5 ± 1.24 years were included. The sensitivity of MA detection was 37.3%, 15.3%, and 4.12% in MC-SLO, OCTA, and CFP, respectively (P < 0.01 in each pair).The positive predictive value was 66.4%, 46.4%, and 27.6% in MC, OCTA, and CFP, respectively (P < 0.01 in each pair). Sensitivity for MAs with early leakage was 36.4% in MC-SLO, which was significantly higher than 4.02% in OCTA. MC-SLO was more useful in detecting MA in eyes with DR than OCTA.

ERM Complex, a Therapeutic Target for Vascular Leakage Induced by Diabetes

BACKGROUND

Ezrin, radixin, and moesin (the ERM complex) interact directly with membrane proteins regulating their attachment to actin filaments. ERM protein activation modifies cytoskeleton organization and alters the endothelial barrier function, thus favoring vascular leakage. However, little is known regarding the role of ERM proteins in diabetic retinopathy (DR).

OBJECTIVE

This study aimed to examine whether overexpression of the ERM complex exists in db/db mice and its main regulating factors.

METHOD

9 male db/db mice and 9 male db/+ aged 14 weeks were analyzed. ERM proteins were assessed by western blot and by immunohistochemistry. Vascular leakage was determined by the Evans blue method. To assess ERM regulation, HRECs were cultured in a medium containing 5.5 mM D-glucose (mimicking physiological conditions) and 25 mM D-glucose (mimicking hyperglycemia that occurs in diabetic patients). Moreover, treatment with TNF-α, IL-1β, or VEGF was added to a high glucose condition. The expression of ERM proteins was quantified by RT-PCR. Cell permeability was evaluated by measuring movements of FITC-dextran.

RESULTS

A significant increase of ERM in diabetic mice in comparison with non-diabetic mice was observed. A high glucose condition alone did not have any effect on ERM expression. However, TNF-α and IL-1β induced a significant increase in ERM proteins.

CONCLUSIONS

The increase of ERM proteins induced by diabetes could be one of the mechanisms involved in vascular leakage and could be considered as a therapeutic target. Moreover, the upregulation of the ERM complex by diabetes is induced by inflammatory mediators rather than by high glucose itself.

Melatonin prevents blood-retinal barrier breakdown and mitochondrial dysfunction in high glucose and hypoxia-induced in vitro diabetic macular edema model

Diabetic macular edema (DME) is a leading cause of blindness in diabetic retinopathy. Prolonged hyperglycemia plus hypoxia contributes to DME pathogenesis. Retinal pigmented epithelial cells comprise the outer blood-retinal barrier and are essential for maintaining physiological functioning of the retina. Melatonin acts as an antioxidant and regulator of mitochondrial bioenergetics and has a protective effect against ocular diseases. However, the role of mitochondrial dysfunction and the therapeutic potential of melatonin in DME remain largely unexplored. Here, we used an in vitro model of DME to investigate blood-retinal barrier integrity and permeability, angiogenesis, mitochondrial dynamics, and apoptosis signaling to evaluate the potential protective efficacy of melatonin in DME. We found that melatonin prevents cell hyper-permeability and outer barrier breakdown by reducing HIF-1α, HIF-1β and VEGF and VEGF receptor gene expression. In addition, melatonin reduced the expression of genes involved in mitochondrial fission (DRP1, hFis1, MIEF2, MFF), mitophagy (PINK, BNip3, NIX), and increased the expression of genes involved in mitochondrial biogenesis (PGC-1α, NRF2, PPAR-γ) to maintain mitochondrial homeostasis. Moreover, melatonin prevented apoptosis of retinal pigmented epithelial cells. Our results suggest that mitochondrial dysfunction may be involved in DME pathology, and melatonin may have therapeutic value in DME, by targeting signaling in mitochondria.

DIABETIC MACULAR EDEMA AND CATARACT SURGERY: Phacoemulsification Combined With Dexamethasone Intravitreal Implant Compared With Standard Phacoemulsification

PURPOSE

To compare functional and anatomical results of combined phacoemulsification and dexamethasone intravitreal implant (Ozurdex; DEX-I) with standard phacoemulsification in diabetic patients with cataract.

METHODS

Retrospective, comparative, cohort study. Patients with nonproliferative diabetic retinopathy, macular edema, and cataract, treated routinely at the Eye Clinic, Azienda Ospedaliero Universitaria Policlinico, Bari, Italy with phacoemulsification associated with DEX-I (n = 23; Phaco-Dex) or standard phacoemulsification (n = 23; Phaco-alone). Best-correct visual acuity, central subfield thickness, and intraocular pressure were assessed at baseline and monthly for 3 months after surgery, and t-test was used to assess change from baseline. A multilevel regression model with an unstructured correlation-type matrix to account for repeated data measures was used for statistical analysis in and between groups.

RESULTS

With Phaco-Dex, best-correct visual acuity increased significantly from the first month (P = 0.0005 vs. baseline) and remained stable at the following visits; central subfield thickness decreased significantly from Month 2 (P = 0.049 and P = 0.04 vs. baseline, respectively); at each timepoint, central subfield thickness was significantly lower in the Phaco-Dex group versus Phaco-alone. Intraocular pressure increased significantly during follow-up (P = 0.001 at Month 3 vs. baseline) but remained within the normal range. In the Phaco-alone group, best-correct visual acuity, and intraocular pressure did not show any significant changes after surgery, whereas central subfield thickness increased from Month 2 (P = 0.05 vs. baseline).

CONCLUSION

In diabetic patients with macular edema and visually significant cataract, combined treatment with phacoemulsification and DEX-I seemed to be effective, safe, and superior to standard phacoemulsification considering both functional and tomographic parameters.

Outcome of Single Dexamethasone Implant Injection in the Treatment of Persistent Diabetic Macular Edema After Anti-VEGF Treatment: Real-Life Data from a Tertiary Hospital in Jordan

Purpose

To analyze the real-life clinical outcome of a single dexamethasone implant (DEX) injection in the treatment of persistent diabetic macular edema (DME) after anti-vascular endothelial growth factor (anti-VEGF) agents in a sample of the Jordanian population.

Methods

An observational case study design that involved a retrospective chart review analysis in a tertiary hospital in Amman, Jordan. Patients who showed persistent DME after receiving at least six doses of anti-VEGF agents for DME treatment were included.

Results

The study population consisted of 72 participants (29 females, 43 males) having an average age of 66 years. All patients had best-corrected visual acuity (BCVA) less than 0.7 (6/9) and SD-OCT documented center-involved DME. The study results showed that the average baseline BCVA improved from 0.205±0.1 before DEX injection to 0.358±0.1 at 3 months post-injection (p<0.0001). The central mean thickness (CMT) showed significant improvement also (539.347±132.402 to 379.041±99.430, p<0.0001). There was a mean of 3 mmHg increase in intraocular pressure at 3 months post-injection (p<0.0001), however, only 4% of patients required medical treatment. Other inflammatory biomarkers in OCT, such as intraretinal hyper-reflective dots (HRD), showed significant improvement also (23.67±16 to 14.83±13, p<0.0001). No other significant safety concerns were noticed.

Conclusion

A single DEX injection showed significant clinical and anatomical improvement in DME cases that are persistent after anti-VEGF treatment in our sample, with an excellent safety profile. In case of supply shortage of intravitreal injections, which occurs frequently at our center, a single DEX injection may be utilized as an effective DME therapy. Further research is mandated to identify clinical response in a larger sample and more frequent injections.

Comparison of Subthreshold 532 nm Diode Micropulse Laser with Conventional Laser Photocoagulation in the Treatment of Non-Centre Involved Clinically Significant Diabetic Macular Edema

BACKGROUND

The aim of the study was to investigate the effect of the 532 nm (green) diode subthreshold micropulse laser (SML) in the treatment of non-centre involved clinically significant macular edema (CSME) in comparison to the conventional laser photocoagulation (CLP).

METHODS

A total of 60 eyes of patients diagnosed with non-centre involved CSME were randomly divided into two groups. SML photocoagulation was performed in the first group (G1), while CLP in the second one (G2). Central macular thickness (CMT) and best corrected visual acuity (BCVA) were measured prior to treatment and at 3 and 6 months after intervention.

RESULTS

G1 participants had significantly better CMT at 6 months after laser application (p = 0.04) compared to G2. Additionally, CMT in both groups was significantly lower 6 months after laser application in comparison to baseline values (G1: p < 0.001, G2: p = 0.002). Moreover, significant improvement was detected 6 months after SML in G1 regarding BCVA compared to values before laser treatment (p = 0.001).

CONCLUSION

SML was more effective than CLP in reducing CMT and improving BCVA in patients with non-centre involved CSME. Therefore, it seems that SML can be a good substitute for CLP in DME treatment if confirmed in future studies.

Histopathological assessments reveal retinal vascular changes, inflammation and gliosis in patients with lethal COVID-19

PURPOSE

To assess for histopathological changes within the retina and the choroid and determine the long-term sequelae of the SARS-CoV-2 infection.

DESIGN

Comparative analysis of human eyes.

SUBJECTS

Eleven donor eyes from COVID-19 positive donors and similar age-matched donor eyes from patients with a negative test for SARS-CoV-2 were assessed.

METHODS

Globes were evaluated ex-vivo with macroscopic, SLO and OCT imaging. Macula and peripheral regions were processed for epon-embedding and immunocytochemistry.

MAIN OUTCOME MEASURES

Retinal thickness and histopathology, detection of SARS-CoV-2 Spike protein, changes in vascular density, gliosis, and degree of inflammation.

RESULTS

Fundus analysis shows hemorrhagic spots and increased vitreous debris in several of the COVID-19 eyes compared to the control. OCT based measurements indicated an increased trend in retinal thickness in the COVID-19 eyes, however the difference was not statistically significant. Histology of the retina showed presence of hemorrhages and central cystoid degeneration in several of the donors. Whole mount analysis of the retina labeled with markers showed changes in retinal microvasculature, increased inflammation, and gliosis in the COVID-19 eyes compared to the controls. The choroidal vasculature displayed localized changes in density and signs of increased inflammation in the COVID-19 samples.

CONCLUSIONS

In situ analysis of the retinal tissue suggested that there are severe subclinical abnormalities that could be detected in the COVID-19 eyes. This study provides a rationale for evaluating the ocular physiology of patients that have recovered from COVID-19 infections to further understand the long-term effects caused by this virus.

Saudi Arabia Guidelines for diabetic macular edema: A consensus of the Saudi Retina Group

Diabetes mellitus (DM) and its complications are major public health burdens in Saudi Arabia. The prevalence of diabetic retinopathy (DR) is 19.7% and the prevalence of diabetic macular edema (DME) is 5.7% in Saudi Arabia. Diabetic macular edema is a vision-threatening complication of DR and a major cause of vision loss worldwide. Ocular treatments include retinal laser photocoagulation, anti-vascular endothelial growth factor (anti-VEGF) agents, intravitreal corticosteroids, and vitreoretinal surgery when necessary. The present consensus was developed as a part of the Saudi Retina Group's efforts to generate Saudi guidelines and consensus for the management of DME, including recommendations for its diagnosis, treatment, and best practice. The experts' panel stipulates that the treatment algorithm should be categorized according to the presence of central macula involvement. In patients with no central macular involvement, laser photocoagulation is recommended as the first-line option. Patients with central macular involvement and no recent history of cardiovascular (CVS) or cerebrovascular disorders can be offered anti-VEGF agents as the first-line option. In the case of non-responders (defined as an improvement of <20% in optical coherence tomography or a gain of fewer than 5 letters in vision), switching to another anti-VEGF agent or steroids should be considered after 3 injections. Within the class of steroids, dexamethasone implants are recommended as the first choice. In patients with a recent history of CVS events, the use of anti-VEGF agents is not recommended, regardless of their lens status. The experts' panel recommends that a future study be conducted to provide a cut-off point for early switching to steroid implants in pseudo-phakic eyes.

Fructus lycii: A Natural Dietary Supplement for Amelioration of Retinal Diseases

Fructus lycii (F. lycii) is an exotic "berry-type" fruit of the plant Lycium barbarum that is characterized by a complex mixture of bioactive compounds distinguished by their high antioxidant potential. F. lycii is used in traditional Chinese home cooking and in the Chinese Pharmacopeia as an aid to vision and longevity as well as a remedy for diabetes to balance "yin" and "yang" in the body for about two centuries. Although a myriad of bioactive compounds have been isolated from F. lycii, polysaccharides, carotenoids, flavonoids, and phenolics represent the key functional components of F. lycii. F. lycii has been shown to exhibit a wide range of biological activities in experimental settings including antioxidant, anti-inflammatory, antiapoptotic, and neuroprotective effects. Despite its medicinal role dating back to the eighteenth century in the Far East and robust evidence of beneficial effects on ocular health and retinal diseases originating mainly from studies in animal models, the role of F. lycii in the clinical management of retinal diseases is yet to be established. This article comprehensively reviews the literature germane to F. lycii and retinal diseases with particular emphasis on age-related macular degeneration, diabetic retinopathy, and retinitis pigmentosa, which are commonly seen in clinical practice.

Foveal Eversion: A Possible Biomarker of Persistent Diabetic Macular Edema

Introduction

We aimed to evaluate the impact of foveal eversion on treatment response and persistent diabetic macular edema (DME).

Methods

The study was designed as interventional and prospective. DME eyes were treated with ranibizumab and/or dexamethasone (DEX) implants, or with fluocinolone acetonide (FAc) implants. FAc-treated eyes were eventually retreated by additional ranibizumab injections. Main outcome measure was the relationship between foveal eversion and both clinical outcome and persistent DME.

Results

Sixty-eight DME eyes (68 patients) treated by anti-VEGF/DEX and 50 FAc-treated eyes (50 patients) were recruited. The follow-up was 16 ± 3 months. The anti-VEGF/DEX group and FAc-treated group were statistically matched for age, sex, DME duration and previous number of injections (p > 0.05). Both groups experienced statistically significant improvements of both BCVA and central macular thickness (p < 0.01) at the end of the follow-up. Persistent DME was shown by 46% of anti-VEGF/DEX eyes and 42% of FAc-treated eyes. Foveal eversion was found in 50% of anti-VEGF/DEX eyes and in 44% of FAc-treated eyes. Its presence was associated with worse anatomical and visual outcome and higher persistence of DME in both groups (p < 0.01) and with higher retreatment percentages in FAc-treated eyes (p < 0.01).

Conclusion

Foveal eversion is associated with worse clinical and morphological outcomes in DME.

Real-World Efficacy and Safety of Fluocinolone Acetonide Implant for Diabetic Macular Edema: A Systematic Review

To assess real-world outcomes of fluocinolone acetonide (FAc) implant in treating diabetic macular edema (DME), a systematic literature review was conducted on PubMed in order to identify publications assessing the efficacy and safety of the FAc implant in DME in daily practice. Case reports and randomized controlled trials were excluded. Twenty-two observational real-world studies analyzing a total of 1880 eyes were included. Mean peak visual gain was +8.7 letters (11.3 months post-FAc injection) and was greater for lower baseline best corrected visual acuity (BCVA) and for more recent DME. Mean central retinal thickness (CRT) decreased 34.3% from baseline. 77.0% of the analyzed studies reported both BCVA improvement of at least five letters and a CRT decrease by 20% or more. Rescue therapy was needed more frequently when FAc was administered for chronic DME. FAc-induced ocular hypertension was reported in 20.1% of patients but only 0.6% needed surgery. Cataract extraction was performed in 43.2% of phakic patients. Adequate patient selection is essential for optimal FAc response and better safety profile. Currently positioned as second- or third-line treatment in the management algorithm, FAc implant decreases treatment burden and provides better letter gain when administered for more recent DME.

Fluorescence lifetime imaging ophthalmoscopy: autofluorescence imaging and beyond

Fluorescence lifetime imaging ophthalmoscopy, FLIO, has gained large interest in the scientific community in the recent years. It is a noninvasive imaging modality that has been shown to provide additional information to conventional imaging modalities. The FLIO device is based on a Heidelberg Engineering Spectralis system. Autofluorescence lifetimes are excited at 473 nm and recorded in two spectral wavelength channels, a short spectral channel (SSC, 498-560 nm) and a long spectral channel (LSC, 560-720 nm). Typically, mean autofluorescence lifetimes in a 30° retinal field are investigated. FLIO shows a clear benefit for imaging different retinal diseases. For example, in age-related macular degeneration (AMD), ring patterns of prolonged FLIO lifetimes 1.5-3.0 mm from the fovea can be appreciated. Macular telangiectasia type 2 (MacTel) shows a different pattern, with prolonged FLIO lifetimes within the typical MacTel zone. In Stargardt disease, retinal flecks can be appreciated even before they are visible with other imaging modalities. Early hydroxychloroquine toxicity appears to be detectable with FLIO. This technique has more potential that has yet to be discovered. This review article focuses on current knowledge as well as pitfalls of this technology. It highlights clinical benefits of FLIO imaging in different ophthalmic and systemic diseases, and provides an outlook with perspectives from the authors.

Quantitative Color Fundus Autofluorescence in Patients with Diabetes Mellitus

A new short wavelength confocal blue-light 450 nm-fundus autofluorescence (color-FAF) allows for visualization of minor fluorophores (e.g., advanced glycation end products, AGEs), besides lipofuscin. The aim of the present pilot study was to quantitatively evaluate color-FAF in patients with diabetes mellitus (DM) and to correlate these data with different stages of retinal disease severity. Optical coherence tomography and color-FAF images of 193 patients/eyes and 18 controls were analyzed using a custom software for quantification of the long (red) and short (green) wavelength components of the emission spectrum (REFC/GEFC). Measurements were performed in nine quadrants of the 6-mm ETDRS macular grid. Foveal GEFC and REFC intensities were higher in patients with DM compared to controls (p = 0.015 and p = 0.006 respectively) and in eyes with center involving diabetic macular edema (DME) compared to eyes without DME (p < 0.001). A positive correlation was found between GEFC and REFC intensities and central retinal thickness, r = 0.37 (p < 0.001) and r = 0.42 (p < 0.001), respectively. No differences were found in color-FAF among different DR severity groups. Quantitative color-FAF could become helpful for the metabolic evaluation of retina in patients with DM and in DME; however, further histologic and immunohistochemical studies on distribution of different retinal fluorophores in DM are needed to better understand its role.

Optical Coherence Tomographic Patterns as Predictors of Structural Outcome After Intravitreal Ranibizumab in Diabetic Macula Edema

Background/Objectives

The purpose of this study was to present an association between the treatment response of diabetic macular edema (DME) to intravitreal ranibizumab (IVR) injections and different morphology patterns using spectral domain optical coherence tomography (SD-OCT).

Subjects/Methods

This retrospective study included 216 eyes of 142 subjects who received IVR for DME and were observed for at least 2 years. Medical charts and SD-OCT images of consecutive patients were reviewed at baseline, 1, 3, 6, 12, and 24 months after first IVR treatment. The OCT patterns were characterized as diffuse retinal thickening (DRT), cystoid macular edema (CME), serous retinal detachment (SRD), and vitreomacular interface abnormalities (VMIAs). All patients were classified into four groups based on the OCT findings.

Results

For a total of 216 eyes, 36 eyes were classified into the DRT group, 76 in the CME group, 42 in the SRD group, and 62 in the VMIA group. There were significant central macula thickness (CMT) improvements in all groups at the 1st month and the 2nd year, except for the DRT group at the 2nd year. Patients with OCT findings of hyperreflective dots (HRDs), metabolic parameters of hyperlipidemia, and coronary artery disease (CAD) had significantly less improvements in CMT at 2-year follow-up (P=0.029, 0.007, <0.001, respectively).

Conclusion

A trend toward decreased effectiveness after long-term IVR treatment was observed in the DRT group. Consistent IVR treatment could still achieve favorable improvement in the reduction of CMT in 2-year follow-up in the VMIA group. Different OCT patterns in DME may affect the therapeutic role of anti-VEGF agents and predict the structure outcome.

Development of a 1-year risk-prediction nomogram for good functional response with anti-VEGF agents in naive diabetic macular oedema

PURPOSE

To develop a risk-prediction nomogram based on baseline variables for good functional response during the 1st year of treatment with anti-VEGF agents in naive diabetic macular oedema (DME).

METHODS

This retrospective study included patients presenting naive-DME treated with anti-VEGF therapy at Dijon University Hospital (France) between 1 February 2012 and 31 March 2015 (derivation cohort). We studied baseline variables that had significant associations with a good functional response to anti-VEGF agents during the 1st year of treatment. We used a program to generate a nomogram based on a binary logistic regression predictive model. Then, this nomogram was tested on data from a separate cohort of naive-DME patients from a multicenter study involving 20 French ophthalmologic centres between January 2014 and June 2015 (validation cohort).

RESULTS

Age, baseline BCVA and ellipsoid zone integrity on spectral-domain optical coherence tomography (SD-OCT) are functional prognostic factors and were used to build a nomogram. The nomogram showed excellent discrimination for good functional responders (area under the curve (AUC) = 0.906, 95% confidence interval (95% CI) = [0.849-0.964], p = 0.004). The discriminative power of this nomogram was tested on the validation cohort data, demonstrating good discrimination of good functional responders (AUC = 0.942, 95% CI = [0.898-0.986], p < 0.001).

CONCLUSION

This nomogram provides a useful estimation of a good functional response in naive-DME patients treated with anti-VEGF agents.

Foveal avascular zone analysis by optical coherence tomography angiography in patients with type 1 and 2 diabetes and without clinical signs of diabetic retinopathy

PURPOSE

To analyze the early macular microvascular alterations in patients with type 1 and 2 diabetes mellitus (DM) without diabetic retinopathy (DR), using optical coherence tomography angiography (OCT-A), and compare these with nondiabetic patients.

METHODS

This prospective study involved 93 patients with type 1 diabetes (DM1), 104 patients with type 2 diabetes (DM2) without signs of DR, and 71 healthy subjects for the control group. The foveal avascular zone (FAZ) area and the vessel density (VD) at the superficial capillary plexus (SCP) and deep capillary plexus (DCP) were evaluated.

RESULTS

The SCP and DCP FAZ areas were significantly larger in the DM1 group in comparison with the controls (p = .001), while no significant differences were observed between the DM2 group and the healthy control group (p = .12). Additionally, no significant differences in FAZ area were found between the DM1 and DM2 groups (p = .26). The VD was significantly reduced in DM1 and DM2 groups compared to controls. A direct correlation was found between the duration of diabetes and SCP FAZ area (r = 0.44; R² = 0.19; p = .0001). Statistically significant differences in the FAZ area at SCP and DCP were observed when comparing patients with a diabetes duration > 10 years and < 10 years in the DM2 group (p = .0001, respectively) and only in the FAZ area at the DCP in the DM1 group (p = .0001).

CONCLUSION

Diabetic patients without DR demonstrate early microvascular alteration in the macular area on OCT-A, which is more pronounced in type I DM, and correlates with the duration of the disease.

Biologic Therapy and Treatment Options in Diabetic Retinopathy with Diabetic Macular Edema

Proliferative diabetic retinopathy and diabetic macular edema can be a potentially sightthreatening disease if not treated correctly. It is directly correlated to the duration of diabetes and how well managed the patients' diabetes is. In the last 15 years, the treatment of diabetic eye disease has taken a quantum leap in methodology due to the group of biological agents named antivascular endothelial growth factor (anti-VEGF). The introduction of the first biological agent has revolutionized the treatment, not only in diabetic eye disease but also across most inflammatory eye diseases, causing leakage of fluid from the blood vessels i.e., in age-related macular degeneration. The availability of these biological agents, despite their considerable costs, have significantly improved the outcomes measured in visual acuity compared to more traditional treatments of diabetic retinopathy in the form of sole laser treatment and glycemic control. The agents demonstrate a favorable safety profile, but if the rarest and most severe side effects occur, there is a potential total loss of vision. This review aims to make an overview of the current pharmaceutical therapeutic options in the treatment of diabetic macular edema. This includes laser therapy, intravitreal steroids, and a primary focus on intravitreal antivascular endothelial growth factors.

New developments in angiography for the diagnosis and management of diabetic retinopathy

The most common microvascular complication of diabetes is diabetic retinopathy, the leading cause of blindness in adults of working age. Our understanding of the vascular changes in diabetic retinopathy was enhanced by the demonstration of fluorescein angiography (FA) in the human retina for the first time in 1961. It was subsequently integrated with digital fundoscopic imaging to become an invaluable technique in evaluation of the retinal vasculature. The recent development of OCT-angiography (OCT-A) has revolutionized the clinician's ability to examine the retinal vasculature without the need for injection of a contrast dye. By coupling OCT, which can provide noninvasive cross-sectional imaging of the central retina, with angiography in OCT-A, one can reveal retinal perfusion by allowing visualization of the depth-resolved retinal capillary plexus. OCT-A has allowed for more precise delineation of changes in the retinal microvasculature, specifically the alterations of retinal vasculature and loss of capillary perfusion from chronic microvascular occlusion in diabetic retinopathy.

Diabetic Macular Edema Management in Asian Population: Expert Panel Consensus Guidelines

PURPOSE

The aim of this consensus article was to provide comprehensive recommendations in the management of diabetic macular edema (DME) by reviewing recent clinical evidence.

DESIGN

A questionnaire containing 47 questions was developed which encompassed clinical scenarios such as treatment response to anti-vascular endothelial growth factor and steroid, treatment side effects, as well as cost and compliance/reimbursement in the management of DME using a Dephi questionnaire as guide.

METHODS

An expert panel of 12 retinal specialists from Singapore, Malaysia, Philippines, India and Vietnam responded to this questionnaire on two separate occasions. The first round responses were compiled, analyzed and discussed in a round table discussion where a consensus was sought through voting. Consensus was considered achieved, when 9 of the 12 panellists (75%) agreed on a recommendation.

RESULTS

The DME patients were initially profiled based on their response to treatment, and the terms target response, adequate response, nonresponse, and inadequate response were defined. The panellists arrived at a consensus on various aspects of DME treatment such as need for classification of patients before treatment, first-line treatment options, appropriate time to switch between treatment modalities, and steroid-related side effects based on which recommendations were derived, and a treatment algorithm was developed.

CONCLUSIONS

This consensus article provides comprehensive, evidence-based treatment guidelines in the management of DME in Asian population. In addition, it also provides recommendations on other aspects of DME management such as steroid treatment for stable glaucoma patients, management of intraocular pressure rise, and recommendations for cataract development.

The ERM Complex: A New Player Involved in Diabetes-induced Vascular Leakage

BACKGROUND

Microvascular complications remain an important cause of morbidity in diabetic patients, and they are associated with a significant economic burden for healthcare systems. Vascular leakage is one of the earlier hallmarks in diabetic microvascular complications. Ezrin, Radixin and Moesin (ERM) proteins have recently been involved in vascular dysfunction under the effect of molecular mediators of diabetes complications. In this review, we will present the available evidence regarding the role of these proteins in vascular leakage and their putative implication in diabetic microvascular complications.

METHODS AND RESULTS

A comprehensive literature search of the electronic MEDLINE database was performed between November 2017 and January 2018. As a result, 36 articles have been reviewed and discussed.

DISCUSSION

ERM proteins are cytoskeleton-membrane linkers, and when activated in endothelial cells are able to induce cytoskeleton reorganization in stress fibers leading to the disassembly of focal adhesions and the formation of paracellular gaps which result in an increase of vascular permeability. The activation of these proteins is induced by mediators involved in diabetic complications such as PKC activation, TNF-α, AGEs and oxidative stress. In conclusion, ERMs play an essential role in endothelium homeostasis and can be envisaged as a new therapeutic molecular target for preventing or arresting diabetes-induced vascular leakage.

Emerging drugs for the treatment of diabetic retinopathy

INTRODUCTION

Diabetic retinopathy (DR) is one of the main pathological features of the diabetes mellitus spectrum. It is estimated that in 2020 about 4 million people worldwide suffered from blindness or visual impairment caused by DR. Many patients cannot access treatment, mostly because of high costs, while others discontinue it prematurely due to the high number of intravitreal administrations required, or the occurrence of ocular complications, or discomfort in quality of life.

AREAS COVERED

The aims of this paper are to summarize the current understanding of the pathogenesis and treatment of diabetic retinopathy, focus on the most promising new approaches to treatment that are being evaluated in clinical trials, and outline the potential financial impact of new drugs in future markets.

EXPERT OPINION

Slow-release systems with steroids, anti-VEGF or sunitinib are promising. Oral imatinib would avoid the ocular complications of intravitreal drugs. Brolucizumab and abicipar pegol may be superior to aflibercept and ranibizumab with the advantage of less frequent administrations. Faricimab, active on Tie-2 receptors, is being evaluated in two phase 3 clinical trials. Further knowledge of the efficacy and safety of these drugs is necessary before their final approval for the treatment of diabetic retinopathy.

The Application of Structural Retinal Biomarkers to Evaluate the Effect of Intravitreal Ranibizumab and Dexamethasone Intravitreal Implant on Treatment of Diabetic Macular Edema

Background: The aim of this study was to compare the therapeutic effect of intravitreal treatment with ranibizumab and dexamethasone using specific swept-source optical coherence tomography retinal biomarkers in patients with diabetic macular edema (DME). Methods: 156 treatment-naïve patients with DME were divided in two groups: 75 patients received 3 monthly intravitreal injections of ranibizumab 0.5 mg (Lucentis^®) (Group 1) and 81 patients received an intravitreal implant of dexamethasone 0.7 mg (Ozurdex^®) (Group 2). Patients were evaluated at baseline (V1), at three months post-treatment in Group 1, and at two months post-treatment in Group 2 (V2). Best-corrected visual acuity (BCVA) and swept source-OCT were recorded at each interval. Changes between V1 and V2 were analyzed using the Wilcoxon test and differences between the two groups of treatment were assessed using the Mann–Whitney test. Multiple regression analysis was performed to evaluate the possible OCT biomarker (CRT, ICR, CT, SND, HRS) as predictive factors for final visual acuity improvement. Results: In both groups, BCVA improved (p-value < 0.0001), and a significant reduction in central retinal thickness, intra-retinal cysts, red dots, hyper-reflective spots (HRS), and serous detachment of neuro-epithelium (SDN) was observed. A superiority of dexamethasone over ranibizumab in reducing the SDN height (p-value = 0.03) and HRS (p-value = 0.01) was documented. Conclusions: Ranibizumab and dexamethasone are effective in the treatment of DME, as demonstrated by functional improvement and morphological biomarker change. DME associated with SDN and HRS represents a specific inflammatory pattern for which dexamethasone appears to be more effective.

Ocular Disease Therapeutics: Design and Delivery of Drugs for Diseases of the Eye

The ocular drug discovery field has evidenced significant advancement in the past decade. The FDA approvals of Rhopressa, Vyzulta, and Roclatan for glaucoma, Brolucizumab for wet age-related macular degeneration (wet AMD), Luxturna for retinitis pigmentosa, Dextenza (0.4 mg dexamethasone intracanalicular insert) for ocular inflammation, ReSure sealant to seal corneal incisions, and Lifitegrast for dry eye represent some of the major developments in the field of ocular therapeutics. A literature survey also indicates that gene therapy, stem cell therapy, and target discovery through genomic research represent significant promise as potential strategies to achieve tissue repair or regeneration and to attain therapeutic benefits in ocular diseases. Overall, the emergence of new technologies coupled with first-in-class entries in ophthalmology are highly anticipated to restructure and boost the future trends in the field of ophthalmic drug discovery. This perspective focuses on various aspects of ocular drug discovery and the recent advances therein. Recent medicinal chemistry campaigns along with a brief overview of the structure-activity relationships of the diverse chemical classes and developments in ocular drug delivery (ODD) are presented.

Choroidal Thickness After Dexamethasone Implant or Aflibercept in Patients with Diabetic Macular Edema Persistent to Ranibizumab

Purpose: This study aims to compare subfoveal choroidal thicknesses (SFCTs) after intravitreal dexamethasone (IVD) or intravitreal aflibercept (IVA) treatment in patients with persistent diabetic macular edema (DME) unresponsive to intravitreal ranibizumab (IVR). Methods: The study consisted of patients with DME unresponsive to IVR treatment in which 37 were administered 1 dose IVD (group A) and 34 patients who were administered 3 doses of IVA (group B), as well as 35 healthy individuals (group C). Detailed ophthalmological examination and optical coherence tomography parameters of group A and group B, including central retinal thickness and SFCT, were retrospectively evaluated before and after treatment. Results from preinjection, and 1, 2, and 3 months after injection were analyzed. Results of group A and group B were compared within themselves and also compared with group C. Results: SFCT measurements were compared within group A and group B (1 = preinjection; 2 = 1 month postinjection; 3 = 2 months postinjection; 4 = 3 months postinjection). There was significant thinning in SFCT between 1-2, 1-3, 1-4, 2-3, 2-4, and 3-4 time intervals within both group A and group B (both P < 0.001). Comparison of SFCT measurements showed preinjection, 1-, and 2-month values of group A were significantly thicker than those of group C (P < 0.001), whereas there was no significant difference between 3-month values (P = 0.09). Preinjection, 1-, and 2-month values of group B were significantly thicker than those of group C (P < 0.001), whereas there was no significant difference between 3-month values (P = 0.06). Conclusions: Three month follow-up showed thinning in SFCT measurements in patients with persistent DME unresponsive to IVR who were applied IVD or IVA treatment.

Outcomes of cataract surgery in eyes with diabetic macular oedema: Data from the Fight Retinal Blindness! Registry

IMPORTANCE

There are limited data on real-world outcomes of cataract surgery in eyes receiving intravitreal treatments for diabetic macular oedema (DMO).

BACKGROUND

Cataract surgery may exacerbate oedema in some eyes with DMO resulting in inferior outcomes.

DESIGN

Matched, case-controlled retrospective study of observational data in routine clinical practice.

PARTICIPANTS

Eyes receiving intravitreal treatments for DMO tracked in the Fight Retinal Blindness! Registry.

METHODS

Eyes that underwent cataract surgery were identified and matched 1:1 with phakic controls also receiving intravitreal injections for DMO. We also assessed potential factors that were associated with better visual acuity (VA) outcomes.

MAIN OUTCOME MEASURES

Change in VA 6 months after cataract surgery.

RESULTS

Cataract surgery was identified in 208 eyes of 156 patients of which 147 eyes had 6 months of observations before and after surgery. The mean VA 6 months after surgery improved by 10.6 letters and was similar to their matched phakic controls (68.8 vs 69.2 letters; P = 0.8). Mean CST both 6 months before (341 μm) and after (360 μm) surgery were similar (P = 0.08). However, these eyes had thicker maculae and they received more injections than their matched phakic controls both before and after surgery. Eyes with worse VA before surgery and those that had received intravitreal treatment in the 4 weeks preceding surgery were more likely to gain vision.

CONCLUSIONS AND RELEVANCE

Visual outcomes of cataract surgery in eyes receiving intravitreal therapy for DMO were reasonably better. Their maculae were thicker and required more injections in the 6 months before and after surgery than their phakic controls.

Corticosteroids for Diabetic Macular Edema

Diabetic macular edema (DME) is a chronic condition with a multifactorial pathogenesis. Vascular endothelial growth factor (VEGF) and several inflammatory mediators are upregulated in eyes with DME. VEGF inhibitors and corticosteroids have all been used successfully in the management of DME. Currently available corticosteroids include triamcinolone acetonide (TA), the dexamethasone (DEX) intravitreal implant, and the fluocinolone acetonide (FA) intravitreal implant. The response to treatment can vary substantially with each treatment modality. Some cases of DME are VEGF driven, and in others, inflammation plays a key role. Chronicity appears to favor corticosteroid treatment. There are no clear guidelines to guide switching from an anti-VEGF to a corticosteroid. Combination therapy of an anti-VEGF drug and a corticosteroid does not appear to provide additional benefit over monotherapy with either drug. The main advantage of corticosteroids over VEGF inhibitors is their longer duration of action. Vitrectomy does not affect the pharmacokinetics of the corticosteroid implants. Common adverse events of corticosteroids include cataract formation, cataract progression, and ocular hypertension. TA may cause a sterile endophthalmitis and pseudoendophthalmitis. Migration of the intravitreal DEX and FA implants into the anterior chamber can be problematic. Because of their less favorable safety profile, corticosteroids are generally used as a second-line treatment for DME. Advantages of using an intravitreal corticosteroid implant include the reduction of treatment burden and predictable pharmacokinetics even in vitrectomized eyes. Pseudophakic eyes, previously vitrectomized eyes and eyes with long-standing DME, particularly of patients who have difficulty in maintaining a monthly appointment, may benefit from primary treatment with a corticosteroid intravitreal implant.

The role of Müller cell glucocorticoid signaling in diabetic retinopathy

Diabetic retinopathy (DR) is a sight-threatening complication associated with the highly prevalent diabetes disorder. Both the microvascular damage and neurodegeneration detected in the retina caused by chronic hyperglycemia have brought special attention to Müller cells, the major macroglia of the retina that are responsible for retinal homeostasis. Given the role of glucocorticoid signaling in anti-inflammatory responses and the almost exclusive expression of glucocorticoid receptors (GRs) in retinal Müller cells, administration of corticosteroid agonists as a potential treatment option has been widely studied. Although these approaches have been moderately efficacious in treating or de-escalating DR pathomechanisms, there are various side effects and gaps of knowledge with regard to introducing exogenous glucocorticoids to the diseased retina. In this paper, we provide a review of the literature concerning the available evidence for the role of Müller cell glucocorticoid signaling in DR and we discuss previously investigated approaches in modulating this system as possible treatment options. Furthermore, we propose a novel alternative to the available choices of treatment by using gene therapy as a tool to regulate the expression of GR in retinal Müller cells. Upregulating GR expression allows for induced glucocorticoid signaling with more enduring effects compared to injection of agonists. Hence, repetitive injections would no longer be required. Lastly, side effects of glucocorticoid therapy such as glucocorticoid resistance of GR following chronic exposure to excess ligands or agonists can be avoided.

Vitreous Proteomics Provides New Insights into Antivascular Endothelial Growth Factor Therapy for Pathologic Myopia Choroid Neovascularization

This study aimed to investigate the protein expression profile of vitreous humor (VH) from pathologic myopic retinoschisis (PMRS) patients with or without intravitreal antivascular endothelial growth factor (anti-VEGF) therapy. VH samples from PMRS patients were subjected to proteomic analysis. Clinical data, including visual acuity, refractive error, and axial length, were recorded, and the fundus optical coherence tomography was performed. Seven PMRS patients were enrolled: 3 PMRS patients as control group, 3 PMRS patients with coexisting choroidal neovascularization (CNV) who developed retinoschisis aggravation after multiple intravitreal conbercept (IVC) injections, and one PMRS patient with coexisting CNV without leakage CNV (CNV-). A total of 310 differentially expressed proteins were identified in these VH samples. The expression of 28 proteins, related to cellular adhesion, protease inhibitors, proangiogenic factors, and antiangiogenic factors, was significantly downregulated in the IVC-treated eyes than in control- and CNV-eyes. α-smooth muscle actin (α-SMA) expression was significantly upregulated in the IVC-treated eyes. Furthermore, the expression of αA-crystallin and fibrillin-1 was significantly upregulated in both IVC and CNV-eyes than in control eyes. These suggest that multiple IVC injections may increase the VH αSMA concentration, which may contribute to posterior hyaloid membrane or retinal inner limiting membrane contraction. Label-free proteomics is an efficient method to provide further insight into the pathogenesis of vitreoretinal diseases.

Factors Predicting Treatment Response in Anti-Vascular Endothelial Growth Factor Naïve Diabetic Macular Edema Patients Treated with Intravitreal Bevacizumab

Purpose: To identify factors that affect the therapeutic response of intravitreal bevacizumab in diabetic macular edema (DMO) and explore the correlation between the functional and anatomical outcomes observed. Methods: A retrospective, noncomparative, consecutive case series design was used. Baseline imaging data and clinical records of 65 eyes with DMO, secondary to type II diabetes mellitus, which received intravitreal bevacizumab for the first time in 2016, were analyzed. The central macular thickness (CMT), macular volume, and best-corrected visual acuity (BCVA), following the initial 3 injection loading phase were recorded. Outcomes were compared to multiple variables including glycemic control, diabetic retinopathy grade, DMO subtype on optical coherence tomography, and use of past macular laser therapy. Results: The participants' age ranged from 46 to 84 of which 63% were men and 37% were women. The mean baseline CMT was 443.21 μm. A mean reduction of 11.23% (P < 0.0005) in CMT was observed following the loading phase. Women exhibited a greater reduction in CMT (P = 0.032). Participants with diffuse retinal thickening (DRT) and with cystoid macular edema (CMO) showed a net reduction in CMT of 17.39% (P = 0.047) and 8.24% (P = 0.04) respectively. Eyes with proliferative diabetic retinopathy demonstrated a mean gain in CMT of 16.86% (P = 0.001). Conclusions: Female patients and DRT demonstrated a positive anatomical response. Patients with CMO and proliferative diabetic retinopathy displayed a negative therapeutic response. Such observations may be considered in clinical decision-making when opting for anti-vascular endothelial growth factor (VEGF) therapy for DMO.

Ocular Carotenoid Status in Health and Disease

Retinal carotenoids are dietary nutrients that uniquely protect the eye from light damage and various retinal pathologies. Their antioxidative properties protect the eye from many retinal diseases, such as age-related macular degeneration. As many retinal diseases are accompanied by low carotenoid levels, accurate noninvasive assessment of carotenoid status can help ophthalmologists identify the patients most likely to benefit from carotenoid supplementation. This review focuses on the different methods available to assess carotenoid status and highlights disease-related changes and potential nutritional interventions.

A review of the putative causal mechanisms associated with lower macular pigment in diabetes mellitus

Macular pigment (MP) confers potent antioxidant and anti-inflammatory effects at the macula, and may therefore protect retinal tissue from the oxidative stress and inflammation associated with ocular disease and ageing. There is a body of evidence implicating oxidative damage and inflammation as underlying pathological processes in diabetic retinopathy. MP has therefore become a focus of research in diabetes, with recent evidence suggesting that individuals with diabetes, particularly type 2 diabetes, have lower MP relative to healthy controls. The present review explores the currently available evidence to illuminate the metabolic perturbations that may possibly be involved in MP's depletion. Metabolic co-morbidities commonly associated with type 2 diabetes, such as overweight/obesity, dyslipidaemia, hyperglycaemia and insulin resistance, may have related and independent relationships with MP. Increased adiposity and dyslipidaemia may adversely affect MP by compromising the availability, transport and assimilation of these dietary carotenoids in the retina. Furthermore, carotenoid intake may be compromised by the dietary deficiencies characteristic of type 2 diabetes, thereby further compromising redox homeostasis. Candidate causal mechanisms to explain the lower MP levels reported in diabetes include increased oxidative stress, inflammation, hyperglycaemia, insulin resistance, overweight/obesity and dyslipidaemia; factors that may negatively affect redox status, and the availability, transport and stabilisation of carotenoids in the retina. Further study in diabetic populations is warranted to fully elucidate these relationships.

Disorganization of retinal inner layers correlates with ellipsoid zone disruption and retinal nerve fiber layer thinning in diabetic retinopathy

PURPOSE

To study the correlation between disorganization of inner retinal layer (DRIL) and macular thickness parameters, ellipsoid zone (EZ) disruption and retinal nerve fiber layer (RNFL) thickness on spectral domain optical coherence tomography (SD-OCT) in diabetic retinopathy (DR), for the first time.

METHODS

A tertiary care center-based cross-sectional study was undertaken. One hundred and four consecutive study subjects of type 2 diabetes mellitus were included: diabetes mellitus with no retinopathy (No DR) (n = 26); non-proliferative DR (NPDR) (n = 26); proliferative DR (PDR) (n = 26) and healthy controls (n = 26). Best Corrected Visual Acuity (BCVA) was measured on the logarithm of the minimum angle of resolution (logMAR) scale. Clinician-friendly, SD-OCT based, grading systems were created for DRIL and EZ disruption, within the macular cube. DRIL was graded as: grade 0, DRIL absent; and grade 1, DRIL present. EZ disruption was graded as; Grade 0: Intact EZ; Grade 1: Focal disruption and Grade 2: Global disruption. Every study subject underwent RNFL thickness analysis.

RESULTS

DRIL was significantly associated with increase in severity of DR.Pearson correlation analysis showed significant positive correlation between DRIL and CST CAT and grades of EZ disruption . However, a significant negative correlation was found between DRIL and RNFL thickness .

CONCLUSION

Presence of DRIL correlates with severity of DR, EZ disruption and RNFL thinning.

Development and characterization of an in vitro system of the human retina using cultured cell lines

BACKGROUND

Previously developed in vitro cultures of the human retina have been solo or dual cell cultures. We developed a triple-cell culture in vitro model utilizing a membrane system to produce a better representation of a functional and morphological human retina.

METHODS

Retinal microvascular endothelial cells (HRMVEC/ACBRI181, cell systems), retinal pigment epithelium cells (RPE/ARPE-19, ATCC) and Müller glial cells (Moorfield Institute of Ophthalmology-Müller 1, UCL) were grown in a triple culture. Our optimized triple-culture media contained a mix of specific endothelial medium and high glucose Dulbecco's Modified Eagle's medium, where all three layers were viable for up to 5 days. Co-culture effect on morphological changes (cell staining) and gene expression of functional genes (pigment epithelium derived factor [PEDF] and vascular endothelial growth factor [VEGF]) were measured from RNA via real-time polymerase chain reaction. Expression of tight junction protein 1 (TJP1) was measured in RNA isolated from ARPE-19s, to assess barrier stability.

RESULTS

The triple-culture promotes certain cell functionality through up-regulation of TJP1, increasing PEDF and decreasing VEGF expression highlighting its importance for the assessment of disease mechanisms distinct from a solo culture which would not allow the true effect of the native microenvironment to be elucidated.

CONCLUSIONS

This model's novelty and reliability allows for the assessment of singular cellular function within the retinal microenvironment and overall assessment of retinal health, while eliminating the requirement of animal-based models.

BMP9 (Bone Morphogenetic Protein-9)/Alk1 (Activin-Like Kinase Receptor Type I) Signaling Prevents Hyperglycemia-Induced Vascular Permeability

Objective- Diabetic macular edema is a major cause of visual impairment. It is caused by blood-retinal barrier breakdown that leads to vascular hyperpermeability. Current therapeutic approaches consist of retinal photocoagulation or targeting VEGF (vascular endothelial growth factor) to limit vascular leakage. However, long-term intravitreal use of anti-VEGFs is associated with potential safety issues, and the identification of alternative regulators of vascular permeability may provide safer therapeutic options. The vascular specific BMP (bone morphogenetic protein) receptor ALK1 (activin-like kinase receptor type I) and its circulating ligand BMP9 have been shown to be potent vascular quiescence factors, but their role in the context of microvascular permeability associated with hyperglycemia has not been evaluated. Approach and Results- We investigated Alk1 signaling in hyperglycemic endothelial cells and assessed whether BMP9/Alk1 signaling could modulate vascular permeability. We show that high glucose concentrations impair Alk1 signaling, both in cultured endothelial cells and in a streptozotocin model of mouse diabetes mellitus. We observed that Alk1 signaling participates in the maintenance of vascular barrier function, as Alk1 haploinsufficiency worsens the vascular leakage observed in diabetic mice. Conversely, sustained delivery of BMP9 by adenoviral vectors significantly decreased the loss of retinal barrier function in diabetic mice. Mechanistically, we demonstrate that Alk1 signaling prevents VEGF-induced phosphorylation of VE-cadherin and induces the expression of occludin, thus strengthening vascular barrier functions. Conclusions- From these data, we suggest that by preventing retinal vascular permeability, BMP9 could serve as a novel therapeutic agent for diabetic macular edema.

First-line treatment algorithm and guidelines in center-involving diabetic macular edema

Management of center-involving diabetic macular edema represents a real therapeutic challenge. Diabetic macular edema is the leading cause of visual acuity impairment in diabetic patients. Since the advent of intravitreal drugs, management of diabetic macular edema has significantly evolved. The historical grid laser photocoagulation is no longer recommended as first-line treatment of diabetic macular edema owing to the findings of the pivotal randomized controlled trials, and anti-vascular endothelial growth factor therapy has emerged as first-line therapy. Steroids also represent a valid treatment option in the management of naïve diabetic macular edema and their efficacy has also been confirmed in several studies. The optimal treatment for diabetic macular edema should consider both general and ophthalmological comorbidities. Patient compliance and motivation should also be carefully evaluated as some treatments require monthly follow-up. Based on recent literature evidence, the present review provides clinicians with a first-line treatment algorithm for center-involving diabetic macular edema tailored to the patient’s individual characteristics.

The subthreshold micropulse laser treatment of the retina restores the oxidant/antioxidant balance and counteracts programmed forms of cell death in the mice eyes

PURPOSE

Subthreshold micropulse laser (SMPL) has been increasingly used for the treatment of different retinal and choroidal macular disorders. However, the exact mechanisms of action have not yet been clearly defined. Therefore, we aimed to examine the role of SMPL treatment in the modulation of oxidant/antioxidant systems, apoptosis and autophagy in the mice eyes.

METHODS

A specific laser contact lens for retina was positioned on the cornea of 40 mice (20 young and 20 old) in order to focus the laser on the eye fundus for SMPL treatment. Within 6 months, 20 animals received one treatment only, whereas the others were treated three times. Eye specimens underwent histological analysis and were used for thiobarbituric acid reactive substances (TBARS) and glutathione (GSH) quantification, as well as for the superoxide dismutase 1 (SOD1) and the selenoprotein thioredoxin reductase 1 (TrxR1) expression evaluation. Western blot was performed for nitric oxide synthase (NOS) subtypes detection and to examine changes in apoptotic/autophagy proteins expression.

RESULTS

SMPL treatment reduced TBARS and increased GSH and SOD1 in the mice eyes. It also reduced cytochrome c, caspase 3 expression and activity and cleaved caspase 9, and increased Beclin 1, p62 and LC3β. The effects were more relevant in the elderly animals.

CONCLUSION

Our results showed that SMPL therapy restored the oxidant/antioxidant balance within retinal layers and modulated programmed forms of cell death. Further studies may confirm these data and could evaluate their relevance in clinical practice.

Lipoprotein-associated phospholipase A2: The story continues

Inflammation is thought to play an important role in the pathogenesis of vascular diseases. Lipoprotein-associated phospholipase A2 (Lp-PLA2) mediates vascular inflammation through the regulation of lipid metabolism in blood, thus, it has been extensively investigated to identify its role in vascular inflammation-related diseases, mainly atherosclerosis. Although darapladib, the most advanced Lp-PLA2 inhibitor, failed to meet the primary endpoints of two large phase III trials in atherosclerosis patients cotreated with standard medical care, the research on Lp-PLA2 has not been terminated. Novel pathogenic, epidemiologic, genetic, and crystallographic studies regarding Lp-PLA2 have been reported recently, while novel inhibitors were identified through a fragment-based lead discovery strategy. More strikingly, recent clinical and preclinical studies revealed that Lp-PLA2 inhibition showed promising therapeutic effects in diabetic macular edema and Alzheimer's disease. In this review, we not only summarized the knowledge of Lp-PLA2 established in the past decades but also emphasized new findings in recent years. We hope this review could be valuable for helping researchers acquire a much deeper insight into the nature of Lp-PLA2, identify more potent and selective Lp-PLA2 inhibitors, and discover the potential indications of Lp-PLA2 inhibitors.

Human vitreous in proliferative diabetic retinopathy: Characterization and translational implications

Diabetic retinopathy (DR) is one of the leading causes of visual impairment in the working-age population. DR is a progressive eye disease caused by long-term accumulation of hyperglycaemia-mediated pathological alterations in the retina of diabetic patients. DR begins with asymptomatic retinal abnormalities and may progress to advanced-stage proliferative diabetic retinopathy (PDR), characterized by neovascularization or preretinal/vitreous haemorrhages. The vitreous, a transparent gel that fills the posterior cavity of the eye, plays a vital role in maintaining ocular function. Structural and molecular alterations of the vitreous, observed during DR progression, are consequences of metabolic and functional modifications of the retinal tissue. Thus, vitreal alterations reflect the pathological events occurring at the vitreoretinal interface. These events are caused by hypoxic, oxidative, inflammatory, neurodegenerative, and leukostatic conditions that occur during diabetes. Conversely, PDR vitreous can exert pathological effects on the diabetic retina, resulting in activation of a vicious cycle that contributes to disease progression. In this review, we recapitulate the major pathological features of DR/PDR, and focus on the structural and molecular changes that characterize the vitreal structure and composition during DR and progression to PDR. In PDR, vitreous represents a reservoir of pathological signalling molecules. Therefore, in this review we discuss how studying the biological activity of the vitreous in different in vitro, ex vivo, and in vivo experimental models can provide insights into the pathogenesis of PDR. In addition, the vitreous from PDR patients can represent a novel tool to obtain preclinical experimental evidences for the development and characterization of new therapeutic drug candidates for PDR therapy.