Panretinal Photocoagulation vs Intravitreous Ranibizumab for Proliferative Diabetic Retinopathy: A Randomized Clinical Trial

Intersession repeatability of visual function and OCTA metrics in eyes with diabetic macular ischaemia

OBJECTIVE

To estimate inter-session coefficient of repeatability (CR) of visual function and OCTA metrics over 3 months in diabetic macular ischaemia (DMI) in stable laser-treated proliferative diabetic retinopathy (PDR) patients.

METHODS

This prospective study recruited patients with stable PDR for at least 6 months following pan-retinal photocoagulation with visual acuity of at least 54 ETDRS letters. DMI was confirmed on OCTA as FAZ area of at least 0.5 mm2 or parafoveal capillary dropout in at least one quadrant if the FAZ area was less than 0.5 mm2. Repeatability was assessed at baseline and 3 months by calculating the coefficients of repeatability (CR) and intraclass correlation coefficient (ICC). The Bland Altman (BA) plots including 95% CI bands for the bias (mean difference) and upper and lower limits of agreement (LOA) were used to visualise the agreement of the measurements.

RESULTS

88 eligible eyes of 63 participants were included in the analysis. The CR for best corrected visual acuity (BCVA) was 10.1 ETDRS letters (95% CI 8.5-11.7 ETDRS letters), and for low luminance visual acuity (LLVA) was 12.4 letters (95% CI 10.4-14.4). The ICC for BCVA and LLVA was 0.81 and 0.75 respectively. For Square Root of Foveal Avascular Zone (SQRT-FAZ) area, CR and ICC was 0.043 mm and 1.00 respectively. The Bland-Altman plots suggest that the level of agreement is wider for vascular density (VD) metrics compared to FAZ parameters.

CONCLUSION

We recommend using the FAZ metrics for quantitative measurements of DMI outcomes due to the excellent repeatability of manually corrected FAZ area.

Current Treatment Options for Diabetic Retinal Disease

The global incidence of diabetes is rising steadily and with it the number of people living with diabetic retinal disease (DRD) is increasing. Like diabetes, DRD can be treated but not cured. In response, therapies to address DRD include targeted ocular and systemic medications. This review discusses diabetes and DRD in terms of current screening recommendations, treatments, and considerations related to those therapies and future drug targets and trials on the horizon. This discourse is targeted at all members of the diabetes care team, including primary care providers, optometrists, and ophthalmologists. The dynamic landscape of diabetic retinopathy treatment is promising for the prevention and improvement of visually significant disease.

Diabetic Retinopathy (DR): Mechanisms, Current Therapies, and Emerging Strategies

Diabetic retinopathy (DR) is one of the most prevalent complications of diabetes, affecting nearly one-third of patients with diabetes mellitus and remaining a leading cause of blindness worldwide. Among the various diabetes-induced complications, DR is of particular importance due to its direct impact on vision and the irreversible damage to the retina. DR is characterized by multiple pathological processes, primarily a hyperglycemia-induced inflammatory response and oxidative stress. Current gold standard therapies, such as anti-VEGF injections and photocoagulation, have shown efficacy in slowing disease progression. However, challenges such as drug resistance, partial therapeutic responses, and the reliance on direct eye injections-which often result in low patient compliance-remain unresolved. This review provides a comprehensive overview of the underlying molecular mechanisms in DR, the current therapies, and their unmet needs for DR treatment. Additionally, emerging therapeutic strategies for improving DR treatment outcomes are discussed.

cGAMP promotes inner blood-retinal barrier breakdown through P2RX7-mediated transportation into microglia

BACKGROUND

Impairment of the inner blood-retinal barrier (iBRB) leads to various blinding diseases including diabetic retinopathy (DR). The cGAS-STING pathway has emerged as a driving force of cardiovascular destruction, but its impact on the neurovascular system is unclear. Here, we show that cGAMP, the endogenous STING agonist, causes iBRB breakdown and retinal degeneration thorough P2RX7-mediated transport into microglia.

METHODS

Extracellular cGAMP and STING pathway were determined in tissue samples from patients with proliferative DR (PDR) and db/db diabetic mice. Histological, molecular, bioinformatic and behavioral analysis accessed effects of cGAMP on iBRB. Single-cell RNA sequencing identified the primary retinal cell type responsive to cGAMP. Specific inhibitors and P2RX7-deficienct mice were used to evaluate P2RX7' role as a cGAMP transporter. The therapeutic effects of P2RX7 inhibitor were tested in db/db mice.

RESULTS

cGAMP was detected in the aqueous humor of patients with PDR and elevated in the vitreous humor with STING activation in db/db mouse retinas. cGAMP administration led to STING-dependent iBRB breakdown and neuron degeneration. Microglia were the primary cells responding to cGAMP, essential for cGAMP-induced iBRB breakdown and visual impairment. The ATP-gated P2RX7 transporter was required for cGAMP import and STING activation in retinal microglia. Contrary to previous thought that mouse P2RX7 nonselectively transports cGAMP only at extremely high ATP concentrations, human P2RX7 directly binds to cGAMP and activates STING under physiological conditions. Clinically, cGAMP-induced microglial signature was recapitulated in fibrovascular membranes from patients with PDR, with P2RX7 being predominantly expressed in microglia. Inhibiting P2RX7 reduced cGAMP-STING activation, protected iBRB and improved neuron survival in diabetic mouse retinas.

CONCLUSIONS

Our study reveals a mechanism for cGAMP-mediated iBRB breakdown and suggests that targeting microglia and P2RX7 may mitigate the deleterious effects of STING activation in retinal diseases linked to iBRB impairment.

Updates on medical and surgical managements of diabetic retinopathy and maculopathy

Diabetic retinopathy (DR) and diabetic macular edema (DME) are leading causes of vision loss globally. This is a comprehensive review focused on both medical and surgical management strategies for DR and DME. This review highlights the epidemiology of DR and DME, with a particular emphasis on the Asia-Pacific region, urban-rural disparities, ethnic variations, and grading methodologies. We examine various risk factors for DR, including glycemic control, hypertension, hyperlipidemia, obesity, chronic kidney disease, sex, myopia, pregnancy, and cataract surgery. Furthermore, we explore potential biomarkers in serum, proteomics, metabolomics, vitreous, microRNA, and genetics that may aid in the detection and management of DR. In addition to medical management, we review the evidence supporting systemic and ocular treatments for DR/DME, including anti-vascular endothelial growth factor (anti-VEGF) agents, anti-inflammatory agents, biosimilars, and integrin inhibitors. Despite advancements in treatment options such as pan-retinal photocoagulation and anti-VEGF agents, a subset of cases still progresses, necessitating vitrectomy. Challenging diabetic vitrectomies pose difficulties due to complex fibrovascular proliferations, incomplete posterior vitreous detachment, and fragile, ischemic retinas, making membrane dissection risky and potentially damaging to the retina. In this review, we address the question of challenging diabetic vitrectomies, providing insights and strategies to minimize complications. Additionally, we briefly explore newer modalities such as 3-dimensional vitrectomy and intra-operative optical coherence tomography as potential tools in diabetic vitrectomy. In conclusion, this review provides a comprehensive overview of both medical and surgical management options for DR and DME. It underscores the importance of a multidisciplinary approach, tailored to the needs of each patient, to optimize visual outcomes and improve the quality of life for those affected by these sight-threatening conditions.

A Markov model assessing the cost-effectiveness of various anti-vascular endothelial growth factor drugs and panretinal photocoagulation for the treatment of proliferative diabetic retinopathy

BACKGROUND

Proliferative diabetic retinopathy (PDR) may lead to vision loss and blindness. The cost-effectiveness of various anti-vascular endothelial growth factor (anti-VEGF) drugs and panretinal photocoagulation (PRP) was assessed to supplement the NICE guideline for treating PDR.

METHODS

A Markov model including eight levels of visual acuity (ranged between >85 and ≤25 letters) was developed to compare the cost-effectiveness of ranibizumab, aflibercept and bevacizumab with PRP (alone or in combination). Clinical inputs in the model were based on literature, while a published network meta-analysis (NMA) informed visual outcomes. Costs were estimated from a UK NHS perspective.

RESULTS

Assuming initial treatment effects from the NMA continued to be applied for the remainder of lifetime, the probabilistic analysis resulted in bevacizumab plus PRP producing the highest net monetary benefit (NMB [95% CI]) of £221,374 [£203,941-£238,388] at £20,000 per quality-adjusted life-year. However, assuming initial treatment effects stabilised over time resulted in PRP alone producing the highest NMB of £223,416 [£209,318-£236,866]. Results were associated with large uncertainty due to wide confidence intervals around vision-based treatment effects of anti-VEGFs versus PRP, particularly for bevacizumab as data were drawn from trials with small sample size and high risk of bias. Using confidential prices for aflibercept and ranibizumab did not change the overall findings.

CONCLUSIONS

PRP is likely to be more cost-effective than anti-VEGFs for PDR. However, the results should be interpreted with caution given the scarcity of long-term visual outcomes with anti-VEGFs in this population. Further research on long-term visual outcomes may resolve these uncertainties.

Early Versus Delayed Vitrectomy for Vitreous Hemorrhage Secondary to Proliferative Diabetic Retinopathy

OBJECTIVE

To compare the clinical outcomes of early pars plana vitrectomy (PPV) versus delayed PPV in patients with first episode of vitreous hemorrhage (VH) secondary to proliferative diabetic retinopathy (PDR).

DESIGN

Retrospective, comparative, interventional study.

SUBJECTS, PARTICIPANTS, AND/OR CONTROLS

Consecutive patients with type 1 or II diabetes diagnosed with new onset VH secondary to PDR who underwent PPV at Moorfields Eye Hospital between December 2014 and December 2016. Exclusions were prior vitrectomy, iris neovascularization, neovascular glaucoma, macular edema, or presence of tractional/rhegmatogenous retinal detachment.

METHODS, INTERVENTION, OR TESTING

Patients were divided into two groups based on the timing of their surgery: early PPV (≤6 weeks) and delayed PPV (>6 weeks). Demographic and clinical features, including best-corrected visual acuity (BCVA), expressed in logMAR at baseline and 12 months were collected. Statistical analyses, including propensity score matching, were performed using Python 3.10, Scikit-learn, Pandas, and GraphPad Prism 10.

MAIN OUTCOME MEASURES

BCVA at 12 months postoperatively, reoperation rates, and severity of complications.

RESULTS

A total of 178 eyes were analyzed (48 early PPV, 130 delayed PPV). The mean (SD) number of weeks before surgery was 3.36 (SD 1.6) for the early PPV group and 22.56 (SD 17.23) for the delayed PPV group (P < .0001). Baseline BCVA prior to PPV was similar between groups (P = .08). At 12 months, the early PPV group had significantly better BCVA (0.40 logMAR vs 0.67 logMAR; P = .02). Patients without evidence of posterior vitreous detachment on ultrasound or OCT showed more pronounced differences (0.3 logMAR vs 0.7 logMAR; P = .001). The early PPV group had fewer sight-threatening complications (P = .005). Multivariable logistic regression identified initial BCVA, early PPV, and absence of preoperative panretinal photocoagulation as significant predictors of better visual outcomes.

CONCLUSIONS

Early PPV significantly improves visual outcomes and reduces severe complications in patients with VH secondary to PDR. These findings support the benefits of early surgical intervention to enhance long-term visual prognosis in these patients. However, a randomized clinical trial is warranted.

Anti-VEGF therapy for proliferative diabetic retinopathy in Kearns-Sayre syndrome

PURPOSE

Multiple mitochondrial syndromes, such as Kearns-Sayre, involve the concurrence of diabetes mellitus and inherited pigmentary retinopathy. It is rare, however, for proliferative disease to develop in these patients as existing inner retinal dysfunction is thought to be protective.

METHODS

To our knowledge this is the first description of proliferative diabetic retinopathy (PDR) in Kearns-Sayre syndrome.

CONCLUSION

A number of additional considerations need to be recognised when treating PDR in Kearns-Sayre syndrome. Given the risk of further visual field losses with panretinal photocoagulation, there should be a preference for primary anti-VEGF therapy in a compliant patient. PDR in inherited retinal disease appears to be very anti-VEGF responsive and may not require the standard monthly frequency of treatment, even from initiation.

A systematic meta-analysis of the prevalence of diabetic retinopathy

BACKGROUND

Diabetic retinopathy (DR), the primary retinal vascular consequence of diabetes mellitus (DM) among people of working age worldwide, is the primary cause of vision impairment and blindness. Despite increasing understanding of the prevalence of DM as a significant public health concern in China, the world's most populous developing nation, there is much to discover about the epidemiology of DR.

OBJECTIVE

This work uses a systematic review and meta-analysis to determine the total prevalence of diabetic retinopathy (DR) in China.

METHODS

Using common keywords, we looked up published research on the prevalence of DR in diabetic patients using Google Scholar, PubMed, and Scopus from their founding until 2023. Using random effects models, pooled estimates of DR prevalence and the associated 95% confidence intervals (CI) were computed. Fifteen articles covering 4837 patients with different forms of diabetes were analyzed. The Egger tests refuted the publication bias assumption for the prevalence of DR (P = 0.825, P = 0.057, respectively). Significant heterogeneity was seen in the prevalence of DR (P < 0.01, I2 = 92% and τ2 = 0.0082), PDR (P < 0.01, I2 = 97% and τ2 = 0.0072), and NPDR (P < 0.01, I2 = 84% and τ2 = 0.0039), according to the results of I2 and τ2 statistics.

RESULTS

The combined prevalence of PDR was 24% (95% CI: 19-28), NPDR was 31% (95% CI: 27-35), and DR was 55% (95% CI: 63-71).

CONCLUSIONS

In summary, DR's prevalence appears slightly higher than that of other studies, with a greater incidence of NPDR. This study emphasises the need for DR screening and treatment in individuals with diabetes.

Cobalt Protoporphyrin Downregulates Hyperglycemia-Induced Inflammation and Enhances Mitochondrial Respiration in Retinal Pigment Epithelial Cells

Diabetic retinopathy is characterized by hyperglycemic retinal pigment epithelial cells that secrete excessive pro-inflammatory cytokines and VEGF, leading to retinal damage and vision loss. Cobalt protoporphyrin (CoPP) is a compound that can reduce inflammatory responses by inducing high levels of HO-1. In the present study, the therapeutic effects of CoPP were examined in ARPE-19 cells under hyperglycemia. ARPE-19 cells were incubated in culture media containing either 5.5 mM (NG) or 25 mM (HG) glucose, with or without the addition of 0.1 µM CoPP. Protein expressions in samples were determined by either Western blotting or immunostaining. A Seahorse metabolic analyzer was used to assess the impact of CoPP treatment on mitochondrial respiration in ARPE-19 cells in NG or HG media. ARPE-19 cells cultured in NG media displayed different cell morphology than those cultured in HG media. CoPP treatment induced high HO-1 expressions and significantly enhanced the viability of ARPE-19 cells under hyperglycemia. Moreover, CoPP significantly downregulated expressions of inflammatory and apoptotic markers and significantly upregulated mitochondrial respiration in APRPE-19 cells under hyperglycemia. CoPP treatment significantly enhanced cell viability in ARPE-19 cells under hyperglycemia. The treatment also downregulated the expressions of pro-inflammatory and upregulated mitochondrial respiration in the hyperglycemic cells.

Investigation of the effect of intravitreal bevacizumab treatment on left heart function using speckle tracking echocardiography

INTRODUCTION AND OBJECTIVES

Vascular endothelial growth factor (VEGF) inhibitors are widely used in oncology and ophthalmology. Although these agents have been shown to increase the risk of cardiovascular events in systemic use, the effect of local applications is unclear. In our study, we aimed to investigate the effects of anti-VEGF agents on left heart functions after intravitreal injection using speckle tracking echocardiography.

METHODS

In this prospectively designed study, 44 patients who were going to start intravitreal anti-VEGF treatment were included in the study. Patients were evaluated with speckle tracking echocardiography before the first anti-VEGF administration and at three months of anti-VEGF treatment.

RESULTS

Global longitudinal strain (GLS) values at three months were lower in the patients who participated in the study and this was statistically significant (-18.77±2.17, -18.60±2.01, p=0.001). Also, there was a statistically significant decrease in the mean values of GLS (GLS4CH) obtained from apical four space image, GLS (GLSAPLAX) obtained from apical long axis image and GLS (GLS2CH) obtained from apical 2 space image at month 0 and month 3 (-19.08±2.39, -18.93±2.26, p=0.004; -18.81±2.29, -18.60±2.12, p=0.001; -18.44±2.31, -18.27±2.12, p=0.013, respectively).

CONCLUSION

The slight decrease in GLS in our study suggests that the use of intravitreal anti-VEGF agents may have cardiac effects.

Macular Capillary Nonperfusion in Eyes With Stable Laser-Treated Proliferative Diabetic Retinopathy

Importance

Some eyes with proliferative diabetic retinopathy (PDR) treated to stability with panretinal photocoagulation (PRP) continue to lose vision without diabetic macular edema. One presumed cause is macular capillary nonperfusion (CNP)-associated ischemia or infarction. Natural history data of macular CNP might guide treatment trials for it.

Objective

To assess visual function and optical coherence tomography angiography (OCTA) changes over 12 months in PRP-treated stable eyes with PDR and macular CNP.

Design, Setting, and Participants

This prospective observational cohort study was conducted in a single center in the United Kingdom. Participants had stable laser-treated PDR in at least 1 eye with macular CNP and a best-corrected visual acuity (BCVA) letter score of at least 54 (Snellen equivalent ≥20/80) using Early Treatment Diabetic Retinopathy Study (ETDRS) chart. Recruitment was from December 2019 to August 2021 and follow-up for 12 months; data were analyzed from May to July 2024.

Main Outcomes and Measures

Changes in BCVA, low-luminance visual acuity (LLVA), and OCTA metrics over 12 months using linear mixed-effects models with unstructured variance accounting for within-participant correlation between the eligible study eye and repeated measures across time.

Results

The cohort included 63 participants and 88 eyes. The mean (SD) age was 57.4 (11.9) years; 41 were male (65.1%) and 22 female (34.9%). Mean BCVA and LLVA ETDRS letter scores were 77.52 (SD, 8.0; approximate Snellen equivalent, 20/32) and 68.33 (SD, 8.9; Snellen, 20/40) at baseline and 78.76 (SD, 8.3; Snellen 20/25) and 70.20 (SD, 8.1; Snellen, 20/40) at 12 months. However, 7 participants (9.3%) lost at least 5 letters of visual acuity at 12 months. Linear mixed-effects analysis showed the foveal avascular zone (FAZ) area deteriorated over 12 months, with a mean increase of 1.80% (95% CI, 0.01%-3.63%; P = .05) at 6 months and 2.26% (95% CI, 0.29%-4.26%; P = .03) from baseline. Eyes that lost 5 or more letters had lower baseline superficial vascular density in both the 3 × 3-mm scan (mean [SD], 36.7 [4.8] vs 33.5 [2.0]; P = .006) and parafoveal area (38.7 [5.6] vs 34.7 [2.6]; P = .005). No association was found between a loss of 5 or more letters at 12 months and any baseline FAZ parameters.

Conclusions and Relevance

This study found that FAZ area deteriorated over 12 months in eyes with stable laser-treated peripheral retina in eyes and macular CNP. Vision loss was uncommon and more prevalent in eyes with decreased SVD at baseline rather than FAZ parameters. Longer trials may be required to observe more events of change of 5 or more letters.

12. Retinopathy, Neuropathy, and Foot Care: Standards of Care in Diabetes-2025

The American Diabetes Association (ADA) "Standards of Care in Diabetes" includes the ADA's current clinical practice recommendations and is intended to provide the components of diabetes care, general treatment goals and guidelines, and tools to evaluate quality of care. Members of the ADA Professional Practice Committee, an interprofessional expert committee, are responsible for updating the Standards of Care annually, or more frequently as warranted. For a detailed description of ADA standards, statements, and reports, as well as the evidence-grading system for ADA's clinical practice recommendations and a full list of Professional Practice Committee members, please refer to Introduction and Methodology. Readers who wish to comment on the Standards of Care are invited to do so at professional.diabetes.org/SOC.

Ultrastructural imaging biomarkers in diabetic macular edema: A major review

Diabetic macular edema (DME) is a vision-threatening complication of diabetic retinopathy and causes significant morbidity in patients. Anti-vascular endothelial growth factor (VEGF) agents are the mainstay of treatment for DME, with steroid implants being used for the treatment of anti-VEGF resistant eyes. Over the years, several classification systems have been devised to describe the patterns of DME using optical coherence tomography (OCT). With the advent of effective treatments, it has become imperative that imaging cues are not merely used for classifying the disease but also as biomarkers for prognostication of disease activity and treatment response. In this aspect, newer imaging findings such as hyperreflective dots, photoreceptor integrity, and disorganization of retinal inner layers have been characterized in detail by several authors. Macular perfusion analysis using OCT angiography is the latest in the armamentarium for imaging DME. In this narrative review, we have summarized all relevant literature related to the ultrastructural imaging-based biomarkers of DME and their correlation to treatment.

Quantitative ultra-widefield fluorescein angiography biomarkers in diabetic retinopathy and association with treatment and progression

Purpose

To determine if demographic factors and calculated areas of nonperfusion (NP) and neovascularization (NV) on ultra-widefield (UWF) fluorescein angiography (FA) in the eyes of patients with diabetes are associated with treatment with intravitreal injections (IVIs), panretinal photocoagulation (PRP), and diabetic retinopathy (DR) progression.

Patients and Methods

This retrospective, cross-sectional study included 363 patients (651 eyes) treated at the University of Michigan Kellogg Eye Center between January 2009 and May 2018. Eligible participants were 18 years or older diagnosed with diabetes who received UWF FA. Patients with previous PRP or poor-quality images were excluded. Main outcome measures included comparison analyses of measured surface areas in millimeters squared (mm2) of total and regional retinal nonperfusion and neovascularization, number of IVIs and PRP treatments, and DR progression.

Results

Our cohort received 3,041 IVIs and 878 PRP treatments with a mean follow-up of 915 days (SD ±714). IVIs were positively associated with posterior NP (difference, 1.15 mm2; 0.43-1.86; P=0.0017). PRP treatments were positively associated with total NP (difference, 27.24 mm2; 14.68-39.79; P<0.001) and total NV (difference, 1.75 mm2; 0.84-2.65; P<0.001), as well as regional areas. While progression was not associated with NP/NV area, it was positively associated with a pre-existing diagnosis of type 2 as compared to type 1 diabetes (147% increase; 7-373% increase; p=0.03).

Conclusion

Areas of NP and NV on UWF FA demonstrated associations with PRP and IVIs in DR patients.

Diabetic retinopathy: A review on its pathophysiology and novel treatment modalities

Diabetes mellitus (DM) is a chronic metabolic non-communicable disease with the ability to cause serious microvascular and macrovascular complications throughout the body, including in the eye. Diabetic retinopathy (DR), present in one-third of patients with diabetes, is a vision-threatening complication caused by uncontrolled diabetes, which greatly affects the retinal blood vessels and the light-sensitive inner retina, eventually leading to blindness. Several epidemiological studies elucidate that DR can vary by age of onset, duration, types of diabetes, and ethnicity. Recent studies show that the pathogenesis of diabetic retinopathy has spread its roots beyond merely being the result of hyperglycemia. The complexity of its etiopathology and diagnosis makes therapeutic intervention challenging. This review throws light on the pathological processes behind DR, the cascade of events that follow it, as well as the available and emerging treatment options.

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.

The Association of Primary Open Angle Glaucoma and Ocular Hypertension with Anti-VEGF Injections

Purpose

To study the effects of anti-VEGF injections on the prevalence of ocular hypertension (OHT), sustained elevated intraocular pressure (SE-IOP), and primary open-angle glaucoma (POAG) with age-matched controls.

Methods

A retrospective case-control study was performed with neovascular age-related macular degeneration (AMD) or diabetic macular edema (DME) against a control group involving atrophic AMD or diabetic retinopathy (DR) without DME. Bevacizumab, ranibizumab, or a combination of both were used in the treatment group. OHT was defined as IOP>21 mm Hg while SE-IOP was defined as IOP that increased by > 6 mmHg or was >25 mm Hg on two or more visits, 30 days apart. Patients with a pre-existing history of glaucoma, vein occlusions, IVI steroids, and pars plana vitrectomy were excluded.

Results

A total of 1312 eyes of 784 patients were included in the study. Using age-matched controls, the treatment and control group was further refined to 394 eyes of 224 patients compared to 340 eyes from 170 patients respectively. The mean age was 58.4 ± 8.7 for the control versus 58.8 ± 8.8 years for the treatment group. The average IOP was higher in the injection group compared to the control with 25.8 ± 9.3 versus 19.5 ± 5.1 mmHg respectively, P<0.001. Significant increases in POAG (10.7% vs 2.9%, p<0.01), OHT (67.0% vs 22.4%, p<0.001), and SE-IOP (41.1% vs 7.6%, p<0.001) were seen in the injection group compared to the age-matched control group. The rates of POAG and OHT were positively associated with the number of injections, R2=0.856, P<0.01 and R2=0.749, P<0.05, respectively.

Conclusion

Compared to age-matched controls, patients treated with anti-VEGF agents demonstrated an increased rate of OHT, SE-IOP, and POAG which correlated with the number of IVIs. However, additional prospective studies are needed to determine if there is a true association between intravitreal anti-VEGF injections and glaucoma.

Effect of Estimated Individual Vitreous Volume on Intraocular Pressure Spikes after Intravitreal Anti-Vascular Endothelial Growth Factors Injection

INTRODUCTION

The present study aimed to evaluate the effect of estimated individual vitreous volume (VV) on intraocular pressure (IOP) spikes after intravitreal anti-vascular endothelial growth factor injections (IVIs).

METHODS

VVs of eyes were calculated using an axial length (AL)-based formula AL3 × (π/6) × 0.76 + 0.012 × (AL - 24), and study eyes were divided into four groups according to their VVs; <4.5 cm3 (Group 1, n = 52), 4.5-5.0 cm3 (Group 2, n = 60), 5.0-5.50 cm3 (Group 3, n = 60), and >5.50 cm3 (Group 4, n = 35). IOP measurements were taken Pre-IVI, immediately after (Post-IVI-0), 5 min (Post-IVI-5), 15 min (Post-IVI-15), and 30 min after the IVI.

RESULTS

A significant IOP change was found between the five-time points in all groups (p < 0.001 for all). Regarding the same time point measurement comparison between the groups, only a statistically significant change was found in the Post-IVI-0 point (p = 0.001). In a post hoc analysis, Group 1, Group 2, and Group 3 had significantly higher IOP values when compared to Group 4 (p < 0.05 for all). Patients treated with prefilled ranibizumab syringes exhibited lower IOP increases than vial-prepared aflibercept injection at the Post-IVI-0 time point (p = 0.042).

CONCLUSIONS

A similar increase in IOP was observed in eyes with low and intermediate volumes, but the increase was less pronounced in those with high volumes after the IVI. Prefilled syringe form showed a lower IOP increase tendency in comparison with vial-prepared forms of the molecules.

Vitrectomy for cases of diabetic retinopathy

Microvascular complications of diabetic retinopathy (DR) may require surgical intervention in the form of vitrectomy. Since its inception, diabetic vitrectomy has evolved with introduction of better instruments, newer techniques, and smaller port sizes. Common indications for diabetic vitrectomy include nonresolving vitreous hemorrhage, tractional retinal detachment, epiretinal membrane, progression of fibrovascular membranes despite laser therapy, recalcitrant diabetic macular edema, and neovascular glaucoma. Preoperative systemic stabilization is essential prior to planning surgery. Surgical techniques commonly used in diabetic vitrectomy are segmentation, delamination, and rarely en-bloc dissection. Modification in surgical techniques such as chandelier-assisted bimanual dissection and pharmacological adjuvants improve surgical outcomes in these patients. Prognosis in these patients could be improved with early intervention. Studies evaluating the outcome of vitrectomy in patients with early proliferative DR are required to understand the appropriate time of intervention in patients. Treatment aimed at arresting the progression of DR and gene therapy are avenues that need further evaluation. The following review will focus on covering the epidemiology of DR, indications of vitrectomy, preoperative considerations, surgical procedures of diabetic vitrectomy, methods of membrane dissection, pharmacological adjuvants to vitrectomy, outcomes of diabetic vitrectomy, and future directions of diabetic vitrectomy.

The multifaceted role of vitreous hyalocytes: Orchestrating inflammation, angiomodulation and erythrophagocytosis in proliferative diabetic retinopathy

BACKGROUND

Despite great advances in proliferative diabetic retinopathy (PDR) therapy over the last decades, one third of treated patients continue to lose vision. While resident vitreous macrophages called hyalocytes have been implicated in the pathophysiology of vitreoretinal proliferative disease previously, little is known about their exact role in PDR. In this study, we address molecular and cellular alterations in the vitreous of PDR patients as a means towards assessing the potential contribution of hyalocytes to disease pathogenesis.

RESULTS

A total of 55 patients were included in this study encompassing RNA-Sequencing analysis of hyalocytes isolated from the vitreous of PDR and control patients, multiplex immunoassay and ELISA analyses of vitreous samples from PDR and control patients, as well as isolation and immunohistochemical staining of cultured porcine hyalocytes. Transcriptional analysis revealed an enhanced inflammatory response of hyalocytes contributing to the cytokine pool within the vitreous of PDR patients by expressing interleukin-6, among others. Further, increased angiopoietin-2 expression indicated that hyalocytes from PDR patients undergo a proangiogenic shift and may thus mediate the formation of retinal neovascularizations, the hallmark of PDR. Finally, RNA-Sequencing revealed an upregulation of factors known from hemoglobin catabolism in hyalocytes from PDR patients. By immunohistochemistry, cultured porcine hyalocytes exposed to red blood cells were shown to engulf and phagocytose these, which reveals hyalocytes' potential to dispose of erythrocytes. Thus, our data suggest a potential role for vitreous macrophages in erythrophagocytosis and, thereby, clearance of vitreous hemorrhage, a severe complication of PDR.

CONCLUSION

Our results strongly indicate a critical role for vitreous hyalocytes in key pathophysiological processes of proliferative diabetic retinopathy: inflammation, angiomodulation and erythrophagocytosis. Immunomodulation of hyalocytes may thus prove an essential novel therapeutic approach in diabetic vitreoretinal disease.

Trends in Medicare Reimbursement and Service Volume of Vitreoretinal Procedures: 2000 to 2021

Purpose: To characterize trends in service volume and inflation-adjusted Medicare reimbursement of vitreoretinal procedures over the past 2 decades. Methods: Medicare Part B National Summary Data Files were accessed to identify the number of allowed services for vitreoretinal procedures. The Medicare Physician Fee Schedule was accessed to identify average annual national reimbursement rates. The Spearman correlation coefficient was used to evaluate time trends for each procedure. All analyses were conducted using Prism 9.5.1 software with 2-sided significance testing and statistical significance set at P ≤ .05. Results: From 2000 to 2021, the 2-tailed Spearman correlation showed that 20 of 38 procedures had statistically significant decreases in service volume over time. Intravitreal injections increased more than 1000-fold, from 2922 in 2000 to 3 444 500 injections in 2021 (ρ = 0.997; P < .001). Panretinal photocoagulation treatments declined from 104 865 to 48 533 procedures (ρ = -0.966; P = .003). Scleral buckling declined from 6502 to 587 procedures (ρ = -0.999; P < .001). Pars plana vitrectomy-associated procedures increased from 71 039 to 95 429 (ρ = 0.691; P < .001). From 2000 to 2021, the 2-tailed Spearman correlation showed that 29 of 38 procedures had statistically significant decreases in reimbursement over time. No procedure had a significant increase in payment. Conclusions: Vitreoretinal practice patterns have changed dramatically over the past 2 decades, with significant declines in inflation-adjusted Medicare reimbursement for most procedures. Awareness of service volume and reimbursement trends is vital to assessing economic viability and patient coverage under the current Medicare payment policies.

Liquid Biopsy for Proliferative Diabetic Retinopathy: Single-Cell Transcriptomics of Human Vitreous Reveals Inflammatory T-Cell Signature

Purpose

Current therapies for proliferative diabetic retinopathy (PDR) do not specifically target VEGF-independent, cell-type-specific processes that lead to vision loss, such as inflammatory pathways. This study aimed to identify targetable cell types and corresponding signaling pathways by elucidating the single-cell landscape of the vitreous of patients with PDR.

Design

Case series.

Subjects

Vitreous and peripheral blood obtained from 5 adult patients (6 eyes) undergoing pars plana vitrectomy for vision-threatening PDR.

Methods

Single-cell RNA sequencing (scRNA-seq) was performed on vitreous cells obtained from diluted cassette washings during vitrectomy from 6 eyes and peripheral blood mononuclear cells (PBMCs, n = 5). Droplet-based scRNA-seq was performed using the Chromium 10x platform to obtain single-cell transcriptomes. Differences in tissue compartments were analyzed with gene ontology enrichment of differentially expressed genes and an unbiased ligand-receptor interaction analysis.

Main Outcome Measures

Single-cell transcriptomic profiles of vitreous and peripheral blood.

Results

Transcriptomes from 13 675 surgically harvested vitreous cells and 22 636 PBMCs were included. Clustering revealed 4 cell states consistently across all eyes with representative transcripts for T cells (CD2, CD3D, CD3E, and GZMA), B cells (CD79A, IGHM, MS4A1 (CD20), and HLA-DRA), myeloid cells (LYZ, CST3, AIF1, and IFI30), and neutrophils (BASP1, CXCR2, S100A8, and S100A9). Most vitreous cells were T cells (91.6%), unlike the peripheral blood (46.2%), whereas neutrophils in the vitreous were essentially absent. The full repertoire of adaptive T cells including CD4+, CD8+ and T regulatory cells (Treg) and innate immune system effectors (i.e., natural killer T cells) was present in the vitreous. Pathway analysis also demonstrated activation of CD4+ and CD8+ memory T cells and ligand-receptor interactions unique to the vitreous.

Conclusions

In the first single-cell transcriptomic characterization of human vitreous in a disease state, we show PDR vitreous is primarily composed of T cells, a critical component of adaptive immunity, with activity and proportions distinct from T cells within the peripheral blood, and neutrophils are essentially absent. These results demonstrate the feasibility of liquid vitreous biopsies via collection of otherwise discarded, diluted cassette washings during vitrectomy to gain mechanistic and therapeutic insights into human vitreoretinal disease.

Financial Disclosures

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Laser-Based Therapy Approaches in the Retina: A Review of Micropulse Laser Therapy for Diabetic Retinopathy

PURPOSE

This review aims to elucidate the mechanisms and clinical utility of subthreshold micropulse laser (SML) therapy in the context of retinal care. Subthreshold or "nondestructive" laser therapy encompasses treatment modalities that induce minimal or no harm to retinal or choroidal tissue and leave no visible sings post-application, while achieving clinical efficacy.

METHODS

A comprehensive review of literature sourced from databases including PubMed, Medline, Embase, Cochrane, and Web of Science was conducted, focusing on articles published before February 2024, and discussing the contemporary use of SML therapy in treating diabetic retinopathy (DR).

RESULTS

The review presents evidence from scientific literature supporting SML therapy as a viable therapeutic approach for management of DR. Across numerous studies, SML therapy has demonstrated safety and additional therapeutic efficacy without causing damage to underlying retinal tissue.

CONCLUSION

Subthreshold laser treatment emerges as a safe strategy for addressing DR. Numerous studies have shown its additional efficacy to anti-VEGF pharmacotherapy, which is the currently approved monotherapy for complications of DR. Ongoing research and clinical investigations aim to further elucidate the mechanisms and optimize the therapeutic advantages of this technology.

Loss to Follow up in Patients with Proliferative Diabetic Retinopathy Treated with Anti-VEGF Therapy and/or Panretinal Photocoagulation in the United States

PURPOSE

To determine the rate of loss to follow up (LTFU) in patients with proliferative diabetic retinopathy (PDR) treated with anti-VEGF therapy and/or panretinal photocoagulation (PRP) in the United States.

DESIGN

Retrospective cohort study using the national IRIS® (Intelligent Research in Sight) Registry data.

SUBJECTS

A total of 73 595 eyes of 56 590 patients with PDR diagnosed between 2013 and 2015 and treated between 2013 and 2018.

METHODS

Multivariable logistic regression models were used to estimate odds ratios (ORs) and 95% confidence intervals (CIs).

MAIN OUTCOME MEASURES

Loss to follow up was no follow up within 12 months from last treatment.

RESULTS

For patient eyes treated for PDR, 11.7% (95% CI, 11.5-12.0) were LTFU. Among patients with PDR treated with anti-VEGF therapy alone, PRP alone, and anti-VEGF and PRP, the rates of LTFU were 12.3% (95% CI, 11.8-12.7), 12.6% (95% CI, 12.1-13.0), and 10.8% (95% CI, 10.4-11.1), respectively. Risk factors for LTFU include Black or African American race/ethnicity (odds ratio [OR], 1.26; 95% CI, 1.13-1.41; P < 0.001), Hispanic ethnicity (OR, 1.28; 95% CI, 1.16-1.42; P < 0.001), Native American/Alaska Native or Native Hawaiian/Other Pacific Islander race/ethnicity (OR, 2.69; 95% CI, 2.14-3.38; P < 0.001), and unilateral disease (OR, 2.05; CI, 1.88-2.23; P < 0.001). Odds for LTFU were higher with patients with baseline vision of 20/50 to 20/200 (OR, 1.25; 95% CI, 1.15-1.36; P < 0.001) and with vision worse than 20/200 (OR, 1.22; 95% CI, 1.05-1.42; P = 0.01) than for patient eyes with a baseline visual acuity of 20/40 or better. Odds for LTFU were lower for Medicare Fee-for-Service (OR, 0.71; 95% CI, 0.64-0.79; P < 0.001) and Medicare Managed (OR, 0.66; 95% CI, 0.56-0.78; P < 0.001) compared with private insurance. Odds for LTFU were lower for patients treated in the Midwest (OR, 0.72; 95% CI, 0.64-0.81; P < 0.001) and West (OR, 0.83; 95% CI, 0.74-0.94; P = 0.003) compared with in the South region.

CONCLUSIONS

The rate of LTFU is between 10% and 12% among patients with PDR who were treated with anti-VEGF injections and/or PRP. Risk factors include Black or African American race/ethnicity, Hispanic ethnicity, baseline vision worse than 20/40, private insurance, South region, and unilateral disease.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Initial Therapy of Panretinal Photocoagulation vs Anti-VEGF Injection for Proliferative Diabetic Retinopathy

Importance

While combined treatment of anti-vascular endothelial growth factor (VEGF) injections plus panretinal photocoagulation (PRP) is a common approach for treating proliferative diabetic retinopathy (PDR) in the clinical practice setting, large randomized clinical trials typically use monotherapy. Subsequently, information is limited as to whether the order of treatment when combining PRP and anti-VEGF injections for PDR affects outcomes.

Objective

To compare outcomes of patients with PDR treated with PRP and subsequent anti-VEGF injections with outcomes of matched patients treated with anti-VEGF injections and subsequent PRP.

Design, Setting, and Participants

This retrospective cohort study used data from January 2003 to January 2024 in the TriNetX aggregated electronic health records network, with data analysis performed in January 2024. Patients with PDR treated with PRP and anti-VEGF injections were eligible for inclusion.

Exposures

Patients with new PDR diagnoses stratified by therapy with PRP and subsequent anti-VEGF injections or anti-VEGF injections and subsequent PRP.

Main Outcomes and Measures

The primary outcome was the need for pars plana vitrectomy (PPV), defined by Current Procedural Terminology codes 67040 or 67113. The secondary outcome included incidence of PPV, vitreous hemorrhage (VH), or tractional retinal detachment (TRD). Relative risk ratios, relative risk differences, and 95% CIs were all calculated for univariate comparison of the cohorts and the development of primary outcomes after matching.

Results

Before propensity score matching (PSM), which controlled for baseline demographic characteristics and medical comorbidities, 2167 patients with PDR treated with PRP first and subsequent anti-VEGF injections and 1549 patients with PDR treated with anti-VEGF injections and subsequent PRP were included. Post-PSM, mean (SD) participant age was 63.0 (13.1) years in cohort 1 (PRP and subsequent anti-VEGF injection) and 63.0 (12.4) years in cohort 2 (anti-VEGF injection and subsequent PRP). Of 1377 total participants in each cohort, 641 patients (46.6%) and 663 patients (48.1%) in cohorts 1 and 2 were female, respectively. Treatment with PRP first and subsequent anti-VEGF injection was associated with higher rates of PPV at 5 years compared with patients treated with anti-VEGF injection and subsequent PRP (relative risk [RR], 1.88; 95% CI, 1.55-2.27; risk difference [RD], 8.93%; 95% CI, 6.31%-11.55%; P < .001), with similar associations at 6 months, 1 year, and 3 years. Treatment with PRP and subsequent anti-VEGF injection was associated with higher rates of VH at 5 years (RR, 1.40; 95% CI, 1.09-1.80; RD, 6.47%; 95% CI, 1.66%-11.29%; P < .001) and TRD at 5 years (RR, 1.85; 95% CI, 1.35-2.53; RD, 4.31%; 95% CI, 2.10%-6.52%; P < .001), with similar findings at 6 months, 1 year, and 3 years compared with patients treated with anti-VEGF injection and subsequent PRP.

Conclusions and Relevance

In this retrospective cohort study, findings suggest that patients with PDR treated with PRP first then subsequent anti-VEGF injection are more likely to undergo PPV for VH and TRD compared with matched patients treated with anti-VEGF agents first, then PRP. These findings support the need for further investigations to determine if the order of PRP and anti-VEGF injections should be considered when treating patients with PDR.

Heterotypic macrophages/microglia differentially contribute to retinal ischaemia and neovascularisation

AIMS/HYPOTHESIS

Diabetic retinopathy is characterised by neuroinflammation that drives neuronal and vascular degenerative pathology, which in many individuals can lead to retinal ischaemia and neovascularisation. Infiltrating macrophages and activated retina-resident microglia have been implicated in the progression of diabetic retinopathy, although the distinct roles of these immune cells remain ill-defined. Our aim was to clarify the distinct roles of macrophages/microglia in the pathogenesis of proliferative ischaemic retinopathies.

METHODS

Murine oxygen-induced retinopathy is commonly used as a model of ischaemia-induced proliferative diabetic retinopathy (PDR). We evaluated the phenotype macrophages/microglia by immunostaining, quantitative real-time RT-PCR (qRT-PCR), flow cytometry and scRNA-seq analysis. In clinical imaging studies of diabetic retinopathy, we used optical coherence tomography (OCT) and OCT angiography.

RESULTS

Immunostaining, qRT-PCR and flow cytometry showed expression levels of M1-like macrophages/microglia markers (CD80, CD68 and nitric oxide synthase 2) and M2-like macrophages/microglia markers (CD206, CD163 and macrophage scavenger receptor 1) were upregulated in areas of retinal ischaemia and around neo-vessels, respectively. scRNA-seq analysis of the ischaemic retina revealed distinct ischaemia-related clusters of macrophages/microglia that express M1 markers as well as C-C chemokine receptor 2. Inhibition of Rho-kinase (ROCK) suppressed CCL2 expression and reduced CCR2-positive M1-like macrophages/microglia in areas of ischaemia. Furthermore, the area of retinal ischaemia was reduced by suppressing blood macrophage infiltration not only by ROCK inhibitor and monocyte chemoattractant protein-1 antibody but also by GdCl3. Clinical imaging studies of diabetic retinopathy using OCT indicated potential involvement of macrophages/microglia represented by hyperreflective foci in areas of reduced perfusion.

CONCLUSIONS/INTERPRETATION

These results collectively indicated that heterotypic macrophages/microglia differentially contribute to retinal ischaemia and neovascularisation in retinal vascular diseases including diabetic retinopathy. This adds important new information that could provide a basis for a more targeted, cell-specific therapeutic approach to prevent progression to sight-threatening PDR.

Aflibercept Biosimilar MYL-1701P vs Reference Aflibercept in Diabetic Macular Edema: The INSIGHT Randomized Clinical Trial

Importance

Biosimilars may be lower-cost alternatives to originator biologic products, potentially offering expanded access or reduced economic burden, but have not been evaluated with aflibercept in diabetic macular edema (DME).

Objective

To compare efficacy and safety of MYL-1701P, an aflibercept biosimilar, with reference aflibercept (Eylea [Regeneron]) in DME.

Design, Setting, and Participants

This was a double-masked, randomized clinical trial that included participants at 77 centers across the US, Europe, Japan, and India. Included in the analysis were individuals 18 years and older with type 1 or type 2 diabetes with central DME and best-corrected visual acuity (BCVA) letter score of 73 to 38 in the study eye using an Early Treatment Diabetic Retinopathy Study (ETDRS) chart. Study data were analyzed from October to December 2021.

Interventions

Formulations of MYL-1701P (0.5-mg vial) or reference aflibercept every 4 weeks for 5 consecutive intravitreal injections, followed by every 8 weeks through week 52.

Main Outcomes and Measures

The primary outcome was the adjusted difference in least squares mean (SE) change from baseline BCVA letter score at week 8 with an equivalence margin of -3 to +3 letters. Secondary outcomes included change in central subfield thickness (CST), BCVA, number of injections over 52 weeks, incidence of adverse events (AEs), and antidrug antibodies (ADAs).

Results

A total of 355 participants (mean [SD] age, 62.2 [9.2] years; 216 male [60.8%]) were randomized to MYL-1701P (179 participants [50.4%]) and aflibercept (176 participants [49.6%]). At week 8, mean (SE) change in BCVA was 6.60 (0.55) letters vs 6.56 (0.55) letters in the MYL-1701P vs aflibercept groups. The adjusted mean difference of 0.04 letters (90% CI, -1.16 to 1.24 letters) met the primary outcome. At week 8, mean (SE) change in CST was -112 (7) μm vs -124 (7) μm in the MYL-1701P vs aflibercept groups (adjusted mean difference, 12 μm; 90% CI, -3 to 26 μm). The incidence of treatment-emergent AEs in the MYL-1701P and aflibercept arms were ocular (30.9% [55 of 178] vs 29.5% [52 of 176]), serious ocular (0.6% [1 of 178] vs 1.1% [2 of 176]), nonocular (65.2% [116 of 178] vs 65.3% [115 of 176]), and serious nonocular (16.9% [30 of 178] vs 11.9% [21 of 176]). The mean (SD) total number of injections was 8.4 (2.1) vs 8.7 (1.8) in the MYL-1701P vs aflibercept groups. The incidence of treatment-induced or treatment-boosted ADAs was 2.8% (5 of 177) vs 5.7% (10 of 176) in the MYL-1701P vs aflibercept arms.

Conclusions and Relevance

MYL-1701P demonstrated clinical equivalence in regard to efficacy, with comparable safety and immunogenicity, to reference aflibercept. These findings support use of MLY-1701P as an alternative to reference aflibercept.

Trial Registration

ClinicalTrials.gov Identifier: NCT03610646.

Personalized Management of Patients with Proliferative Diabetic Vitreoretinopathy

Purpose: To evaluate prognostic factors for visual outcome in patients with diabetes who have undergone vitrectomy (PPV) for severe proliferative diabetic vitreoretinopathy (PDVR) in at least one eye in the past 15 years. Methods: Medical records of 132 eyes of 66 patients were analyzed (median age 52 years 21-80; patients with type 1/2 diabetes 40/26; median follow-up 38 months 9-125). Correlations between final favorable visual outcome defined as 0.5≤ best-corrected visual acuity (BCVA) and prognostic factors (age, sex, type and duration of diabetes, metabolic status, BCVA, diabetic retinopathy status, data of preoperative management, data of vitrectomy, and postoperative complications) were analyzed. Results: BCVA improved significantly in the entire study cohort (from median 0.05 min-max 0.001-1 to 0.32, 0.001-1, p < 0.001). Visual stabilization was achieved in the majority of patients, and good visual acuity (0.5 ≤ BCVA) was maintained in more than one-third of the eyes. Multivariable GEE statistics showed that in addition to the duration of diabetes and stable HbA1c values, only preoperative tractional macular detachment proved to be an independent significant predictor of visual outcome. Conclusions: Pars plana vitrectomy is a useful tool when performed early before tractional macular detachment. However, long-term visual stability can only be achieved with good metabolic control.

Intravitreal Antiangiogenic Treatment for Diabetic Retinopathy: A Mexican Real-Life Scenario Experience

The objective of this study was to analyze the effectiveness of two intravitreal antiangiogenic drugs, ranibizumab and aflibercept, in a Mexican population over a period of 5 years, evaluating the improvement in visual acuity (VA) and central retinal thickness (CRT) in a real-world scenario. This is a retrospective study with subjects diagnosed with diabetic retinopathy (DR), proliferative diabetic retinopathy (PDR), and diabetic macular edema (DME) receiving intravitreal injections of ranibizumab and/or aflibercept. In this study, we analyzed 588 eyes of 294 patients who received intravitreal antiangiogenic injections. The results showed an improvement regardless of antiangiogenic treatment or diagnosis in both VA and CRT. We found that both aflibercept and ranibizumab improved VA, while subjects with DME responded less to antiangiogenic treatment (p < 0.05), and that this difference did not correspond to the CRT measured by OCT. These results support evidence that intravitreal antiangiogenic medications are effective for ophthalmic complications of diabetes in our population; however, damage to visual structures is not reversed in most patients. And that the perception by the patient (VA) and that of the ophthalmologist (CRT) do not completely correlate in our study.

Enhanced Ocular Delivery of Beva via Ultra-Small Polymeric Micelles for Noninvasive Anti-VEGF Therapy

Pathological ocular neovascularization resulting from retinal ischemia constitutes a major cause of vision loss. Current anti-VEGF therapies rely on burdensome intravitreal injections of Bevacizumab (Beva). Herein ultrasmall polymeric micelles encapsulating Beva (P@Beva) are developed for noninvasive topical delivery to posterior eye tissues. Beva is efficiently loaded into 11 nm micelles fabricated via self-assembly of hyperbranched amphiphilic copolymers. The neutral, brush-like micelles demonstrate excellent drug encapsulation and colloidal stability. In vitro, P@Beva enhances intracellular delivery of Beva in ocular cells versus free drug. Ex vivo corneal and conjunctival-sclera-choroidal tissues transport after eye drops are improved 23-fold and 7.9-fold, respectively. Anti-angiogenic bioactivity is retained with P@Beva eliciting greater inhibition of endothelial tube formation and choroid sprouting over Beva alone. Remarkably, in an oxygen-induced retinopathy (OIR) model, topical P@Beva matching efficacy of intravitreal Beva injection, is the clinical standard. Comprehensive biocompatibility verifies safety. Overall, this pioneering protein delivery platform holds promise to shift paradigms from invasive intravitreal injections toward simplified, noninvasive administration of biotherapeutics targeting posterior eye diseases.

Glucagon-like Peptide 1 Receptor Agonist use and the effect on diabetic retinopathy: An uncertain relationship

Glucagon-like Peptide 1 Receptor Agonists (GLP-1 RAs) are a group of relatively novel medications for the treatment of diabetes mellitus. These medications can mimic the naturally occurring incretins of the body, which promote the release of insulin in response to hyperglycaemia. The anti-glycaemic effects of these medications can be profound and carry other metabolic benefits such as promoting weight loss. Clinical trials have shown GLP-1 RAs are safe to use from a cardiovascular perspective. However, some trials have suggested a link between GLP-1 RA use and worsening diabetic retinopathy. The conclusions surrounding this link are poorly established as data is drawn primarily from cardiovascular outcome trials. If an association does exist, a possible explanation might be the observed phenomenon of early worsening diabetic retinopathy with rapid correction of hyperglycaemic states. Trials which look at diabetic retinopathy as a primary outcome in relation to use of GLP-1 RAs are sparse and warrant investigation given the growing use of this group of medications. Therefore currently, it is uncertain what effect, beneficial or adverse, GLP-1 RA use has on diabetic retinopathy. This article provides an overview of GLP-1 RA use as a treatment for diabetes mellitus and the current understanding of their relationship with diabetic retinopathy.

Evaluation of Foveal Vasculature by Optical Coherence Tomography Angiography after Pan-Retinal Photocoagulation versus Intravitreal Anti-VEGF Injections

Purpose

This study aimed to compare macular vascular changes one and three months after treatment with either panretinal photocoagulation (PRP) or intravitreal bevacizumab (IVB).

Methods

A total of 62 eyes with very severe non-proliferative diabetic retinopathy or early proliferative diabetic retinopathy without center-involved diabetic macular edema, were included in this retrospective study. Thirty-nine eyes were allocated to the PRP group, while 23 eyes were treated with IVB. Optical coherence tomography angiography (OCTA) was performed to measure foveal avascular zone (FAZ) characteristics as well as the densities of superficial and deep capillary plexuses (SCP and DCP).

Results

In the IVB group, the FAZ area and perimeter expanded at month one but returned to baseline level after three months. In the PRP group, however, the FAZ area and perimeter were rather steady. Changes in the FAZ area were significantly different between the treatment groups at month one (P = 0.02), but not at month three (P = 0.31). There was no significant difference in the change in FAZ circularity index between the two groups at each time point (P = 0.55 and P = 0.31). Similarly, changes in SCP density were not statistically significant between the two groups at both time points (all Ps > 0.05). A comparison of the two treatment arms based on the mean change in DCP density revealed a significant difference at month one, but not at month three (P = 0.01 and P = 0.49, respectively).

Conclusion

Although bevacizumab and PRP have different short-term macular vascular responses, both therapies have the ability to normalize or stabilize vascular measures over time.

Morphology, Fundus Autofluorescence, and Retinal Sensitivity of Photocoagulated Lesions in Proliferative Diabetic Retinopathy

Purpose

To evaluate the relationships among morphology, fundus autofluorescence (FAF), and retinal sensitivity of photocoagulated lesions more than 1 year after panretinal photocoagulation in patients with proliferative diabetic retinopathy and good vision.

Methods

This retrospective cohort study included patients with proliferative diabetic retinopathy who had undergone panretinal photocoagulation more than 1 year ago. The photocoagulated lesions were classified according to FAF levels: group A, no FAF; group B, diffuse FAF; group C, white-dotted centers with diffuse FAF; group D, white-dotted centers without FAF; and group E, controls. The main outcome measures were FAF, retinal sensitivity, and morphology of the photocoagulated lesions.

Results

The median sensitivity values and number of photocoagulated lesions in groups A (n = 37), B (n = 39), C (n = 4), D (n = 15), and E (n = 39) were 0 dB, 18.0 dB, 13.9 dB, 0.3 dB, and 21.5 dB, respectively. EZ lines were absent in 93.5%, 18.1%, 50%, 93.3%, and 0% of lesions in groups A, B, C, D, and E, respectively. The inner retinal layer was damaged in 45.2%, 3.0%, 50%, 73.3%, and 0% lesions in groups A, B, C, D, and E, respectively. Statistically significant between-group differences were observed in the retinal sensitivities of the photocoagulated lesions, presence of EZ lines, and damage to the inner retinal layer (p < 0.05).

Conclusions

The photoreceptors in most photocoagulated lesions with diffuse FAF retain their morphology and function.

Translational Relevance

Using fundus autofluorescence, the damage to photoreceptors after panretinal photocoagulation in patients with diabetes can be estimated in a noninvasive manner. This process can help in determining the need for additional panretinal photocoagulation.

Progression to Pars Plana Vitrectomy in Patients With Proliferative Diabetic Retinopathy

Importance

The Diabetic Retinopathy Clinical Research Network Protocol S suggested that vitrectomy for vitreous hemorrhage (VH) or tractional retinal detachment (TRD) was more common among eyes assigned initially to panretinal photocoagulation (PRP) vs anti-vascular endothelial growth factor (anti-VEGF) for proliferative diabetic retinopathy (PDR). These clinical implications warrant further evaluation in the clinical practice setting.

Objective

To explore outcomes of PDR treated with PRP monotherapy compared with matched patients treated with anti-VEGF monotherapy.

Design, Setting, and Participants

Retrospective cohort study using an aggregated electronic health records research network. Patients with PDR who received PRP or anti-VEGF monotherapy between January and September 2023 were included before propensity score matching. Patients were excluded with 6 or fewer months' follow-up after monotherapy or with a combination of PRP and anti-VEGF. Data were analyzed in September 2023.

Exposures

Patients with new PDR diagnoses stratified by monotherapy with PRP or anti-VEGF agents using Current Procedural Terminology code.

Main Outcome Measures

Incidence of pars plana vitrectomy (PPV), VH, or TRD.

Results

Among 6020 patients (PRP cohort: mean [SD] age, 64.8 [13.4]; 6424 [50.88%] female; 3562 [28.21%] Black, 6180 [48.95%] White, and 2716 [21.51%] unknown race; anti-VEGF cohort: mean [SD] age, 66.1 [13.2]; 5399 [50.52%] male; 2859 [26.75%] Black, 5377 [50.31%] White, and 2382 [22.29%] unknown race) who received treatment, PRP monotherapy was associated with higher rates of PPV when compared with patients treated with anti-VEGF monotherapy at 5 years (RR, 1.18; 95% CI, 1.05-1.36; RD, 1.37%; 95% CI, 0.39%-2.37%; P < .001), with similar associations at 1 and 3 years. PRP monotherapy was associated with higher rates of VH at 5 years (relative risk [RR], 1.72; 95% CI, 1.52-1.95; risk difference [RD], 7.05; 95% CI, 5.41%-8.69%; P < .001) and higher rates of TRD at 5 years (RR, 2.76; 95% CI, 2.26-3.37; RD, 4.25%; 95% CI, 3.45%-5.05%; P < .001), with similar magnitudes of associations at 6 months, 1 year, and 3 years, when compared with patients treated with anti-VEGF monotherapy.

Conclusions and Relevance

These findings support the hypothesis that patients with PDR treated with PRP monotherapy are more likely to develop VH, TRD, and undergo PPV when compared with matched patients treated with anti-VEGF monotherapy. However, given the wide range in relative risk, confounding factors may account for some of the association between PRP vs anti-VEGF monotherapy and outcomes evaluated.

Erythropoiesis-Stimulating Agents and the Risk of Vision-Threatening Diabetic Retinopathy

PURPOSE

Animal studies have suggested that Erythropoiesis-Stimulating Agents (ESAs) may increase vascular endothelial growth factor (VEGF)-related retinopathies, but this effect is unclear in humans. This study evaluates the risk of vision-threatening diabetic retinopathy (VTDR), defined as either diabetic macular edema (DME) or proliferative diabetic retinopathy (PDR), in patients exposed to an ESA.

METHODS

Two analyses were performed. First, a retrospective matched-cohort study was designed using a de-identified commercial and Medicare Advantage medical claims database. The ESA cohort of non-proliferative diabetic retinopathy patients who were new users of an ESA from 2000 to 2022 was matched to controls up to a 3:1 ratio. Exclusion criteria included less than 2 years in the plan, history of VTDR or history of other retinopathy. Multivariable Cox proportional hazards regression with inverse proportional treatment weighting (IPTW) was used to assess the hazard of developing VTDR, DME, and PDR. The second analysis was a self-controlled case series (SCCS) evaluating the incidence rate ratios (IRR) of VTDR during 30-day periods before and after initiating an ESA.

RESULTS

After inclusion of 1502 ESA-exposed patients compared with 2656 controls, IPTW-adjusted hazard ratios found the ESA cohort had an increased hazard of progressing to VTDR (HR = 3.0 95%CI:2.3-3.8;p < .001) and DME (HR = 3.4,95%CI:2.6-4.4,p < .001), but not PDR (HR = 1.0,95%CI:0.5-2.3,p = .95). Similar results were found within the SCCS which demonstrated higher IRRs for VTDR (IRRs = 1.09-1.18;p < .001) and DME (IRRs = 1.16-1.18;p < .001), but not increased IRRs in PDR (IRR = 0.92-0.97,p = .02-0.39).

CONCLUSION

ESAs are associated with higher risks for VTDR and DME, but not PDR. Those studying ESAs as adjunctive therapy for DR should be cautious of possible unintended effects.

Practical Utility of Widefield OCT Angiography to Detect Retinal Neovascularization in Eyes with Proliferative Diabetic Retinopathy

PURPOSE

To assess the real clinical utility of widefield OCT angiography (WF-OCTA) for detecting retinal neovascularization (RNV) in eyes with proliferative diabetic retinopathy (PDR).

DESIGN

A retrospective cross sectional study.

PARTICIPANTS

Consecutive eyes clinically suspected of PDR by physicians at a tertiary eye center between March 2021 and November 2022.

METHODS

All eyes underwent ultrawidefield fluorescein angiography (UWF-FA) (California, Optos) and WF-OCTA (S1, Canon) with a 23 × 20 mm scan area. Two independent graders detected individual RNV lesions using UWF-FA and used them as the ground truth. Widefield OCT angiography images were first evaluated to determine whether the images successfully illustrated retinal vasculature, regardless of the image quality index or the presence of vitreous hemorrhage. The graders then identified the RNV lesions with WF-OCTA. We detected RNV by utilizing both the entire retinal slab, including flow signals in the retina, and the custom vitreoretinal interface slab, defined as flow signals from 20 μm below the internal limiting membrane (ILM) to 2000 μm above the ILM. We evaluated the applicability to real clinical practice by not correcting segmentation errors.

MAIN OUTCOME MEASURES

The success rate of imaging and the detection rate of RNV using WF-OCTA.

RESULTS

Initially, 69 consecutive patients who underwent UWF-FA were identified. Of these, 114 eyes from 57 (83%) patients underwent both UWF-FA and WF-OCTA. Of the 114 eyes, 108 (95%) produced gradable WF-OCTA images. Using UWF-FA, the graders identified 175 RNV lesions in 40 eyes. Widefield OCT angiography achieved a sensitivity of 95% and specificity of 88% for detecting eyes with RNV. At the level of individual RNV lesions, graders detected 156 RNV lesions with WF-OCTA, with 118 of these confirmed by UWF-FA (true positive). Among the 57 false-negative lesions, the primary causes were being out of the scan range (26 lesions) and segmentation errors (21 lesions).

CONCLUSIONS

Widefield OCT angiography imaging had a high success rate, achieving a sensitivity of 95% and a specificity of 88% for detecting eyes with RNV in a real clinical setting. Despite a 67% detection rate for individual RNV lesions, WF-OCTA may serve as a valuable noninvasive method for RNV detection in eyes with diabetic retinopathy.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Diabetic Disease of the Eye in Canada: Consensus Statements from a Retina Specialist Working Group

Despite advances in systemic care, diabetic disease of the eye (DDE) remains the leading cause of blindness worldwide. There is a critical gap of up-to-date, evidence-based guidance for ophthalmologists in Canada that includes evidence from recent randomized controlled trials. Previous guidance has not always given special consideration to applying treatments and managing DDE in the context of the healthcare system. This consensus statement aims to assist practitioners in the field by providing a spectrum of acceptable opinions on DDE treatment and management from recognized experts in the field. In compiling evidence and generating consensus, a working group of retinal specialists in Canada addressed clinical questions surrounding the four themes of disease, patient, management, and collaboration. The working group reviewed literature representing the highest level of evidence on DDE and shared their opinions on topics surrounding the epidemiology and pathophysiology of diabetic retinopathy and diabetic macular edema; diagnosis and monitoring; considerations around diabetes medication use; strategic considerations for management given systemic comorbidities, ocular comorbidities, and pregnancy; treatment goals and modalities for diabetic macular edema, non-proliferative and proliferative diabetic retinopathy, and retinal detachment; and interdisciplinary collaboration. Ultimately, this work highlighted that the retinal examination in DDE not only informs the treating ophthalmologist but can serve as a global index for disease progression across many tissues of the body. It highlighted further that DDE can be treated regardless of diabetic control, that a systemic approach to patient care will result in the best health outcomes, and prevention of visual complications requires a multidisciplinary management approach. Ophthalmologists must tailor their clinical approach to the needs and circumstances of individual patients and work within the realities of their healthcare setting.

COMPARISON OF THE EFFICACY AND SAFETY OF RANIBIZUMAB 0.5 MG VERSUS 1.0 MG WITH PARS PLANA VITRECTOMY FOR THE TREATMENT OF PROLIFERATIVE DIABETIC RETINOPATHY: A Randomized Controlled Trial

PURPOSE

To investigate the effectiveness of two regimens of ranibizumab-assisted pars plana vitrectomy in the treatment of patients with proliferative diabetic retinopathy.

METHODS

This is a prospective, 6-month, randomized controlled trial. Eighty patients with 87 eyes requiring pars plana vitrectomy treatment for proliferative diabetic retinopathy were included and randomly divided into a 1.0-mg injection group and a 0.5-mg injection group. The ranibizumab was delivered intraoperatively, at the close of surgery. The vitreous hemorrhage grade, best-corrected visual acuity, central macular thickness, and safety data were assessed to Month 6.

RESULTS

The 1.0-mg injection group had a milder grade and a lower reoccurrence rate of early postoperatively vitreous hemorrhage than the 0.5-mg injection group (35.0% and 63.4%, respectively, P = 0.0195). The mean best-corrected visual acuity of two groups was significantly improved from baseline to 6 months after surgery, 1.60 ± 0.72 Logarithm of the Minimum Angle of Resolution (LogMAR) (<20/200) to 0.47 ± 0.49 LogMAR (20/59) for the 1.0-mg injection group and 1.51 ± 0.69 LogMAR (<20/200) to 0.50 ± 0.31 LogMAR (20/63) for the 0.5-mg injection group, but there was no significant difference between the two groups ( P = 0.74). There was no significant difference in the mean decrease in central macular thickness and probability of postoperative adverse events between the two groups.

CONCLUSION

Intravitreal injection of 1.0 mg of ranibizumab after pars plana vitrectomy compared with the recommended dose of 0.5 mg significantly reduced the recurrence and severity of early postoperative vitreous hemorrhage in patients with proliferative diabetic retinopathy. It also contributed to the early recovery of visual acuity after surgery and did not increase postoperative adverse events.

Roles of Sirt1 and its modulators in diabetic microangiopathy: A review

Diabetic vascular complications include diabetic macroangiopathy and diabetic microangiopathy. Diabetic microangiopathy is characterised by impaired microvascular endothelial function, basement membrane thickening, and microthrombosis, which may promote renal, ocular, cardiac, and peripheral system damage in diabetic patients. Therefore, new preventive and therapeutic strategies are urgently required. Sirt1, a member of the nicotinamide adenine dinucleotide-dependent histone deacetylase class III family, regulates different organ growth and development, oxidative stress, mitochondrial function, metabolism, inflammation, and aging. Sirt1 is downregulated in vascular injury and microangiopathy. Moreover, its expression and distribution in different organs correlate with age and play critical regulatory roles in oxidative stress and inflammation. This review introduces the background of diabetic microangiopathy and the main functions of Sirt1. Then, the relationship between Sirt1 and different diabetic microangiopathies and the regulatory roles mediated by different cells are described. Finally, we summarize the modulators that target Sirt1 to ameliorate diabetic microangiopathy as an essential preventive and therapeutic measure for diabetic microangiopathy. In conclusion, targeting Sirt1 may be a new therapeutic strategy for diabetic microangiopathy.

Multidimensional sleep health and diabetic retinopathy: Systematic review and meta-analysis

Diabetic retinopathy (DR) is one of the most prevalent microvascular diabetic complications. Poor sleep health and obstructive sleep apnea (OSA) are risk factors for diabetes and poor glycemic control. Recent studies have suggested associations between poor sleep health/OSA and DR. Furthermore, there have been suggestions of melatonin dysregulation in the context of DR. We conducted a systematic review and meta-analysis exploring the associations between multidimensional sleep health (duration, satisfaction, efficiency, timing/regularity and alertness), OSA and melatonin with DR. Forty-two studies were included. Long, but not short sleep, was significantly associated with DR, OR 1.41 (95%CI 1.21, 1.64). Poor sleep satisfaction was also significantly associated with DR, OR 2.04 (1.41, 2.94). Sleep efficiency and alertness were not associated with DR, while the evidence on timing/regularity was scant. Having OSA was significantly associated with having DR, OR 1.34 (1.07, 1.69). Further, those with DR had significantly lower melatonin/melatonin metabolite levels than those without DR, standardized mean difference -0.94 (-1.44, -0.44). We explored whether treating OSA with continuous positive airway pressure (CPAP) led to improvement in DR (five studies). The results were mixed among studies, but potential benefits were observed in some. This review highlights the association between poor multidimensional sleep health and DR.

The Economic Burden of Diabetic Retinopathy in Jordan: Cost Analysis and Associated Factors

Objective

Diabetic retinopathy (DR) is the leading cause of visual loss worldwide in patients with diabetes mellitus (DM). The aims of our study are to describe the costs associated with (DR) and to evaluate its economic impact in Jordan.

Methods

Retrospectively, we included all patients with DM and classified them according to the severity of DR. Data regarding medical history, ophthalmic history, stage of DR, presence of DME, and the ophthalmic procedures and operations were collected. The total DR-related cost was measured as a direct medical cost for the outpatient and inpatient services.

Results

Two hundred and twenty-nine patients were included in the study. Only 49.7% of the patients presented without DR, and 21% presented with diabetic macular edema (DME) unilaterally or bilaterally. The DR-related cost was significantly associated with insulin-based regimens, longer duration of DM, higher HbA1c levels, worse stage of DR at presentation, the presence of DME at presentation, the presence of glaucoma, and increased mean number of intravitreal injections, laser sessions, and surgical operations. Multivariate analysis should the presenting stage of DR, presence of DME, and the presence of DME be the independent factors affecting the DR-related cost.

Conclusion

This study is the first study to be conducted in Jordan and encourages us to establish a screening program for DR for earlier detection and treatment. DM control and treatment compliance will reduce the heavy costs of the already exhausted healthcare and financial system.

Longitudinal Quantitative Ultrawidefield Angiographic Features in Diabetic Retinopathy Treated with Aflibercept from the Intravitreal Aflibercept as Indicated by Real-Time Objective Imaging to Achieve Diabetic Retinopathy Improvement Trial

OBJECTIVE

To report longitudinal trends of quantitative ultrawidefield fluorescein angiography (qUWFA) biomarkers in the Intravitreal Aflibercept as Indicated by Real-Time Objective Imaging to Achieve Diabetic Retinopathy Improvement (PRIME) diabetic retinopathy (DR) clinical trial.

DESIGN

Post hoc analysis of the PRIME prospective randomized DR clinical trial comparing intravitreal aflibercept treatment based on the DR severity score (DRSS) or quantitative leakage index for DR improvement (ClinicalTrials.gov identifier: NCT03531294).

PARTICIPANTS

Patients were enrolled with a DRSS level of 47A to 71A and best-corrected visual acuity of 20/800 or better. Key exclusion criteria were previous intravitreal injection, panretinal photocoagulation, vitrectomy, central-involving macular edema, or vitreous hemorrhage.

METHODS

A previously validated, machine learning-based qUWFA analysis platform was used for panretinal leakage index assessment and differentiation of generalized and perivascular leakage phenotypes. Additionally, microaneurysm count and ischemic index were quantified in panretinal and macular regions. The trends in these biomarkers and therapeutic response were studied over 1 year.

MAIN OUTCOME MEASURES

Longitudinal trends of qUWFA biomarkers. The impact of these qUWFA metrics on treatment response was assessed by studying their associations with time to 2-step DRSS improvement and number of treatment-free days.

RESULTS

Forty eyes from 40 subjects with DR were enrolled. Lower baseline generalized leakage was noted in eyes that attained the 2-step DRSS improvement in < 16 weeks (1.9% vs. 2.8%; P = 0.026). Baseline macular perivascular-generalized leakage ratio had a significant correlation with the number of treatment-free days (r = 0.4; P = 0.012). At the end of 1 year, therapy significantly reduced the mean panretinal (3.9% vs. 5.8%; P = 0.002) and macular (6.2% vs. 12.2%; P = 0.008) generalized leakage indices compared with baseline, as well as the mean panretinal perivascular leakage index (1.5% vs. 2.3%; P = 0.002). The mean panretinal ischemic index demonstrated a small but likely clinically insignificant decrease from 12.5% at baseline to 11.6% at year 1 (P = 0.016).

CONCLUSIONS

Down-trending leakage indices and microaneurysm counts were demonstrated over 1 year of anti-VEGF therapy. At baseline, DR eyes with lower generalized leakage responded to therapy more rapidly. Eyes with greater perivascular leakage relative to generalized leakage showed a longer-lasting anti-VEGF treatment response.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Requirement of Site-Specific Tyrosine Phosphorylation of Cortactin in Retinal Neovascularization and Vascular Leakage

BACKGROUND

Retinal neovascularization is a major cause of vision impairment. Therefore, the purpose of this study is to investigate the mechanisms by which hypoxia triggers the development of abnormal and leaky blood vessels.

METHODS

A variety of cellular and molecular approaches as well as tissue-specific knockout mice were used to investigate the role of Cttn (cortactin) in retinal neovascularization and vascular leakage.

RESULTS

We found that VEGFA (vascular endothelial growth factor A) stimulates Cttn phosphorylation at Y421, Y453, and Y470 residues in human retinal microvascular endothelial cells. In addition, we observed that while blockade of Cttn phosphorylation at Y470 inhibited VEGFA-induced human retinal microvascular endothelial cell angiogenic events, suppression of Y421 phosphorylation protected endothelial barrier integrity from disruption by VEGFA. In line with these observations, while blockade of Cttn phosphorylation at Y470 negated oxygen-induced retinopathy-induced retinal neovascularization, interference with Y421 phosphorylation prevented VEGFA/oxygen-induced retinopathy-induced vascular leakage. Mechanistically, while phosphorylation at Y470 was required for its interaction with Arp2/3 and CDC6 facilitating actin polymerization and DNA synthesis, respectively, Cttn phosphorylation at Y421 leads to its dissociation from VE-cadherin, resulting in adherens junction disruption. Furthermore, whereas Cttn phosphorylation at Y470 residue was dependent on Lyn, its phosphorylation at Y421 residue required Syk activation. Accordingly, lentivirus-mediated expression of shRNA targeting Lyn or Syk levels inhibited oxygen-induced retinopathy-induced retinal neovascularization and vascular leakage, respectively.

CONCLUSIONS

The above observations show for the first time that phosphorylation of Cttn is involved in a site-specific manner in the regulation of retinal neovascularization and vascular leakage. In view of these findings, Cttn could be a novel target for the development of therapeutics against vascular diseases such as retinal neovascularization and vascular leakage.

A Review on Diabetic Retinopathy

Diabetic retinopathy is a well-recognised microvascular complication of diabetes and is among the leading cause of blindness all over the world. Over the last decade, there have been advances in the diagnosis of diabetic retinopathy and diabetic macular edema. At the same time, newer therapies for the management of diabetic retinopathy have evolved. As a result of these advances, a decline in severe vision loss due to diabetes has been witnessed in some developing countries. However, there is a steady increase in the number of people affected with diabetes, and is expected to rise further in the coming years. Therefore, it is prudent to identify diabetic retinopathy, and timely intervention is needed to decrease the burden of severe vision loss. An effort has been made to review all the existing knowledge regarding diabetic retinopathy in this article and summarize the present treatment options for diabetic retinopathy.