Current treatments in diabetic macular oedema: systematic review and meta-analysis

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.

Diabetic Macular Edema Management: A Review of Anti-Vascular Endothelial Growth Factor (VEGF) Therapies

Diabetic macular edema (DME) is a major cause of vision impairment in diabetic individuals, characterized by fluid accumulation in the macula due to a breakdown of the blood-retinal barrier (BRB). This review article explores the role of anti-vascular endothelial growth factor (anti-VEGF) therapies in the management of DME. Anti-VEGF treatments, including ranibizumab, bevacizumab, and aflibercept, have revolutionized DME management by targeting VEGF, a key mediator in DME pathogenesis. We critically examined the efficacy of these therapies in reducing macular edema and improving visual acuity, assessed their safety and tolerability, and explored the variability in treatment response. The review highlights the latest advancements and future directions in anti-VEGF therapy, including novel drug delivery systems and emerging treatment paradigms. By providing a comprehensive overview of current anti-VEGF therapies, this review seeks to inform clinical practice, guide future research, and contribute to improved patient outcomes in DME management.

Microbiome and Retinal Vascular Diseases

The gut microbiome consists of more than a thousand different microbes and their associated genes and microbial metabolites. It influences various host metabolic pathways and is therefore important for homeostasis. In recent years, its influence on health and disease has been extensively researched. Dysbiosis, or imbalance in the gut microbiome, is associated with several diseases. Consequent chronic inflammation may lead to or promote inflammatory bowel disease, obesity, diabetes mellitus, atherosclerosis, alcoholic and non-alcoholic liver disease, cirrhosis, hepatocellular carcinoma, and other diseases. The pathogenesis of the three most common retinal vascular diseases, diabetic retinopathy, retinal vein occlusion, and retinal artery occlusion, may also be influenced by an altered microbiome and associated risk factors such as diabetes mellitus, atherosclerosis, hypertension, and obesity. Direct cause-effect relationships remain less well understood. A potential prevention or treatment modality for these diseases could be targeting and modulating the individual's gut microbiome.

Diabetes more than retinopathy, it’s effect on the anterior segment of eye

Diabetes mellitus (DM) is one of the chronic metabolic noncommunicable diseases that has attained worldwide epidemics. It threatens healthy life around the globe, with mild-to-severe secondary complications and leads to significant illness including nephropathy, neuropathy, retinopathy, and macrovascular abnormalities including peripheral vasculopathy, and ischaemic heart disease. Research into diabetic retinopathy (DR), which affects one-third of persons with diabetes, has made considerable strides in recent years. In addition, it can lead to several anterior segment complications such as glaucoma, cataract, cornea, conjunctiva, lacrimal glands and other ocular surface diseases. Uncontrolled DM also caused gradual damage to corneal nerves and epithelial cells, which raises the likelihood of anterior segment diseases including corneal ulcers, dry eye disease, and chronic epithelial abnormalities. Although DR and other associated ocular complications are well-known, the complexity of its aetiology and diagnosis makes therapeutic intervention challenging. Strict glycaemic control, early detection and regular screening, and meticulous management is the key to halting the progression of the disease. In this review manuscript, we aim to provide an in-depth understanding of the broad spectrum of diabetic complications in the anterior segment of the ocular tissues and illustrate the progression of diabetes and its pathophysiology, epidemiology, and prospective therapeutic targets. This first such review article will highlight the role of diagnosing and treating patients with a plethora of anterior segment diseases associated with diabetes, which are often neglected.

Reduced expression of Basigin gene products in response to chronic inflammation may contribute to vision loss

Chronic inflammation of the retina, like that of diabetic retinopathy, disrupts the blood-retina barrier (BRB). Disruption of the BRB increases vascular permeability and leads to vision loss. Basigin gene products, cell-adhesion molecules and members of the immunoglobulin superfamily, are expressed on endothelial cells, photoreceptor cells and Müller glial cells. Basigin variant-1 on photoreceptors interacts with Basigin variant-2 on Müller glial cells and to rod-derived cone viability factor (RdCVF) to form metabolic support mechanisms necessary for the survival of photoreceptor neurons. The goal of the current study was to determine the gene expression changes of Basigin gene products in ex vivo neonatal, adolescent, and adult retina when exposed to an inflammatory insult in acute and chronic phases. Retinas extracted from mice at postnatal day (P) 7, 30, and 180 were incubated with either phosphate-buffered saline (PBS), as a control, or lipopolysaccharide (LPS), an endotoxin, for 3, 6, 12, or 24 h. RNA was then extracted and Basigin gene products were quantified by qPCR. Analyses indicate both gene products are influenced by LPS exposure in a time and age dependent manner. Specifically, P180 retinas exposed to LPS showed significant decreases in both Basigin gene products, suggesting older retinas may be susceptible to chronic inflammation and subsequent vision loss.

Diagnostic circulating biomarkers to detect vision-threatening diabetic retinopathy: Potential screening tool of the future?

With the increasing prevalence of diabetes in developing and developed countries, the socio-economic burden of diabetic retinopathy (DR), the leading complication of diabetes, is growing. Diabetic retinopathy (DR) is currently one of the leading causes of blindness in working-age adults worldwide. Robust methodologies exist to detect and monitor DR; however, these rely on specialist imaging techniques and qualified practitioners. This makes detecting and monitoring DR expensive and time-consuming, which is particularly problematic in developing countries where many patients will be remote and have little contact with specialist medical centres. Diabetic retinopathy (DR) is largely asymptomatic until late in the pathology. Therefore, early identification and stratification of vision-threatening DR (VTDR) is highly desirable and will ameliorate the global impact of this disease. A simple, reliable and more cost-effective test would greatly assist in decreasing the burden of DR around the world. Here, we evaluate and review data on circulating protein biomarkers, which have been verified in the context of DR. We also discuss the challenges and developments necessary to translate these promising data into clinically useful assays, to detect VTDR, and their potential integration into simple point-of-care testing devices.

Proteome changes associated with the VEGFR pathway and immune system in diabetic macular edema patients at different diabetic retinopathy stages

PURPOSE

Diabetic macular edema (DME) is a major cause of vision loss in all stages of diabetic retinopathy (DR). However, there is limited recognition of aqueous humor (AH) proteome profiles of DME patients at different DR stages. In this study, we aimed to investigate the AH proteome changes between DME patients at the nonproliferative diabetic retinopathy (NPDR) stage and those at the proliferative diabetic retinopathy (PDR) stage.

METHODS

A label-free data-independent acquisition based liquid chromatography tandem mass spectrometry (LC-MS/MS) analysis was performed to profile the abundances of AH proteins in 73 eyes from DME patients at different DR stages. Enzyme-linked immunosorbent assay (ELISA) was used to confirm the proteomics results with AH samples from non-diabetic patients and DME patients at the NPDR or PDR stage.

RESULTS

LC-MS/MS results showed significantly changed expression of 308 proteins between DME patients in the NPDR and PDR groups. Compared to the NPDR group, the proteins relatively up-regulated in the PDR group are involved in the immune system and/or negative regulation of the cell cycle, while proteins relatively down-regulated in the PDR group are associated with the vascular endothelial growth factor receptor (VEGFR) pathway and/or metabolism. ELISA results further verified the proteomic result of down-regulated expression of the immune-associated protein cystatin C (CST3) in the PDR group compared to that in the NPDR and non-diabetic groups.

CONCLUSIONS

In this study, we reported for the first time the decreased abundances of AH proteins associated with the VEGFR pathway and both down- and up-regulated expression of AH proteins associated with the immune system in the PDR group compared to that in the NPDR group. Furthermore, we found negative correlations of immune-associated protein, CST3 concentration in AH with DR severity and central retinal thickness, suggesting CST3 as a promising target independent of the VEGFR pathway in DME-involved DR treatment.

LRG1: an emerging player in disease pathogenesis

The secreted glycoprotein leucine-rich α-2 glycoprotein 1 (LRG1) was first described as a key player in pathogenic ocular neovascularization almost a decade ago. Since then, an increasing number of publications have reported the involvement of LRG1 in multiple human conditions including cancer, diabetes, cardiovascular disease, neurological disease, and inflammatory disorders. The purpose of this review is to provide, for the first time, a comprehensive overview of the LRG1 literature considering its role in health and disease. Although LRG1 is constitutively expressed by hepatocytes and neutrophils, Lrg1-/- mice show no overt phenotypic abnormality suggesting that LRG1 is essentially redundant in development and homeostasis. However, emerging data are challenging this view by suggesting a novel role for LRG1 in innate immunity and preservation of tissue integrity. While our understanding of beneficial LRG1 functions in physiology remains limited, a consistent body of evidence shows that, in response to various inflammatory stimuli, LRG1 expression is induced and directly contributes to disease pathogenesis. Its potential role as a biomarker for the diagnosis, prognosis and monitoring of multiple conditions is widely discussed while dissecting the mechanisms underlying LRG1 pathogenic functions. Emphasis is given to the role that LRG1 plays as a vasculopathic factor where it disrupts the cellular interactions normally required for the formation and maintenance of mature vessels, thereby indirectly contributing to the establishment of a highly hypoxic and immunosuppressive microenvironment. In addition, LRG1 has also been reported to affect other cell types (including epithelial, immune, mesenchymal and cancer cells) mostly by modulating the TGFβ signalling pathway in a context-dependent manner. Crucially, animal studies have shown that LRG1 inhibition, through gene deletion or a function-blocking antibody, is sufficient to attenuate disease progression. In view of this, and taking into consideration its role as an upstream modifier of TGFβ signalling, LRG1 is suggested as a potentially important therapeutic target. While further investigations are needed to fill gaps in our current understanding of LRG1 function, the studies reviewed here confirm LRG1 as a pleiotropic and pathogenic signalling molecule providing a strong rationale for its use in the clinic as a biomarker and therapeutic target.

Dexamethasone intravitreal implant (Ozurdex) in diabetic macular edema: real-world data versus clinical trials outcomes

AIM

To investigate the safety and efficacy of intravitreal dexamethasone implants (Ozurdex^®/DEX) in patients with diabetic macular edema (DME) either naïve or non-naïve to anti-VEGF therapies who switched to DEX implant independent of response to anti-vascular endothelial growth factors (anti-VEGFs).

METHODS

This was an audit retrospective review of medical records of patients with DME who switched to the DEX intravitreal implant. Patients were divided into 2 groups: patients naïve to antiangiogenic therapy and patients who were previously treated with anti-VEGFs. Data regarding demographics, changes in mean best-corrected visual acuity (BCVA), central macular thickness (CMT), and intraocular pressure (IOP) was collected over 6mo. The demographic data mean changes in BCVA, CMT, and IOP were compared. Six-month follow-up data of 47 patients (57 eyes), who either switched to DEX implant irrespective of response to previous treatments or were treatment naïve before receiving DEX implant, was collected.

RESULTS

Improvement in mean BCVA was observed from 1-4mo after injection with a decreased effect at month 6 as expected, with better outcomes in naïve compared to non-naïve patients. A statistically relevant decrease in mean CMT was observed during the follow-up period. An increase in mean IOP was observed in the first 2mo after DEX therapy. The mean number of injections of the overall population during the 6mo was 1.3. A subgroup analysis showed no relevant difference between phakic versus pseudophakic patients relative to measured outcomes. There was no cataract progression during the follow-up period and no adverse events reported.

CONCLUSION

This real-life setting study shows that intravitreal DEX implant is effective and safe. The timings of greater therapeutic impact are concordant with previous studies and suggest that earlier treatment with corticosteroids may have an additional benefit in naïve patients.

IL-17A Damages the Blood-Retinal Barrier through Activating the Janus Kinase 1 Pathway

Blood-retinal barrier (BRB) dysfunction underlies macular oedema in many sight-threatening conditions, including diabetic macular oedema, neovascular age-related macular degeneration and uveoretinitis. Inflammation plays an important role in BRB dysfunction. This study aimed to understand the role of the inflammatory cytokine IL-17A in BRB dysfunction and the mechanism involved. Human retinal pigment epithelial (RPE) cell line ARPE19 and murine brain endothelial line bEnd.3 were cultured on transwell membranes to model the outer BRB and inner BRB, respectively. IL-17A treatment (3 days in bEnd.3 cells and 6 days in ARPE19 cells) disrupted the distribution of claudin-5 in bEnd.3 cells and ZO-1 in ARPE19 cells, reduced the transepithelial/transendothelial electrical resistance (TEER) and increased permeability to FITC-tracers in vitro. Intravitreal (20 ng/1 μL/eye) or intravenous (20 ng/g) injection of recombinant IL-17A induced retinal albumin leakage within 48 h in C57BL/6J mice. Mechanistically, IL-17A induced Janus kinase 1 (JAK1) phosphorylation in bEnd.3 but not ARPE19 cells. Blocking JAK1 with Tofacitinib prevented IL-17A-mediated claudin-5 dysmorphia in bEnd.3 cells and reduced albumin leakage in IL-17A-treated mice. Our results suggest that IL-17A can damage the BRB through the activating the JAK1 signaling pathway, and targeting this pathway may be a novel approach to treat inflammation-induced macular oedema.

Recent trends in drug-delivery systems for the treatment of diabetic retinopathy and associated fibrosis

Diabetic retinopathy is a frequent microvascular complication of diabetes and a major cause of visual impairment. In advanced stages, the abnormal neovascularization can lead to fibrosis and subsequent tractional retinal detachment and blindness. The low bioavailability of the drugs at the target site imposed by the anatomic and physiologic barriers within the eye, requires long term treatments with frequent injections that often compromise patient's compliance and increase the risk of developing more complications. In recent years, much effort has been put towards the development of new drug delivery platforms aiming to enhance their permeation, to prolong their retention time at the target site and to provide a sustained release with reduced toxicity and improved efficacy. This review provides an overview of the etiology and pathophysiology of diabetic retinopathy and current treatments. It addresses the specific challenges associated to the different ocular delivery routes and provides a critical review of the most recent developments made in the drug delivery field.

An overview of diabetic retinopathy and other ocular complications of diabetes mellitus

Diabetic retinopathy is a major cause of preventable sight loss in the working-age population and a major global health issue. It is caused by chronic hyperglycaemia, which also predisposes patients with diabetes mellitus to a range of other ocular complications including diabetic macular oedema, eye infections, diabetic cataract, and dry eye and corneal complications. Ocular complications of diabetes can significantly affect people's quality of life, so regular eye screening from the point of diabetes diagnosis, as well as a multidisciplinary team approach, are required to identify these complications early, manage them effectively, and support patients to achieve glycaemic control. This article provides an overview of diabetic retinopathy and other ocular complications of diabetes, and explains the role of the nurse in providing health promotion, patient education and support.

Polymer-free corticosteroid dimer implants for controlled and sustained drug delivery

Polymeric drug carriers are widely used for providing temporal and/or spatial control of drug delivery, with corticosteroids being one class of drugs that have benefitted from their use for the treatment of inflammatory-mediated conditions. However, these polymer-based systems often have limited drug-loading capacity, suboptimal release kinetics, and/or promote adverse inflammatory responses. This manuscript investigates and describes a strategy for achieving controlled delivery of corticosteroids, based on a discovery that low molecular weight corticosteroid dimers can be processed into drug delivery implant materials using a broad range of established fabrication methods, without the use of polymers or excipients. These implants undergo surface erosion, achieving tightly controlled and reproducible drug release kinetics in vitro. As an example, when used as ocular implants in rats, a dexamethasone dimer implant is shown to effectively inhibit inflammation induced by lipopolysaccharide. In a rabbit model, dexamethasone dimer intravitreal implants demonstrate predictable pharmacokinetics and significantly extend drug release duration and efficacy (>6 months) compared to a leading commercial polymeric dexamethasone-releasing implant.

Galectins in the Pathogenesis of Common Retinal Disease

Diseases of the retina are major causes of visual impairment and blindness in developed countries and, due to an ageing population, their prevalence is continually rising. The lack of effective therapies and the limitations of those currently in use highlight the importance of continued research into the pathogenesis of these diseases. Vascular endothelial growth factor (VEGF) plays a major role in driving vascular dysfunction in retinal disease and has therefore become a key therapeutic target. Recent evidence also points to a potentially similarly important role of galectins, a family of β-galactoside-binding proteins. Indeed, they have been implicated in regulating fundamental processes, including vascular hyperpermeability, angiogenesis, neuroinflammation, and oxidative stress, all of which also play a prominent role in retinopathies. Here, we review direct evidence for pathological roles of galectins in retinal disease. In addition, we extrapolate potential roles of galectins in the retina from evidence in cancer, immune and neuro-biology. We conclude that there is value in increasing understanding of galectin function in retinal biology, in particular in the context of the retinal vasculature and microglia. With greater insight, recent clinical developments of galectin-targeting drugs could potentially also be of benefit to the clinical management of many blinding diseases.

AMP-activated protein kinase is a key regulator of acute neurovascular permeability

Many neuronal and retinal disorders are associated with pathological hyperpermeability of the microvasculature. We have used explants of rodent retinae to study acute neurovascular permeability, signal transduction and the role of AMP-activated protein kinase (AMPK). Following stimulation with either vascular endothelial growth factor (VEGF-A) or bradykinin (BK), AMPK was rapidly and strongly phosphorylated and acted as a key mediator of permeability downstream of Ca2+. Accordingly, AMPK agonists potently induced acute retinal vascular leakage. AMPK activation led to phosphorylation of endothelial nitric oxide synthase (eNOS, also known as NOS3), which in turn increased VE-cadherin (CDH5) phosphorylation on Y685. In parallel, AMPK also mediated phosphorylation of p38 MAP kinases (hereafter p38) and HSP27 (HSPB1), indicating that it regulated paracellular junctions and cellular contractility, both previously associated with endothelial permeability. Endothelial AMPK provided a missing link in neurovascular permeability, connecting Ca2+ transients to the activation of eNOS and p38, irrespective of the permeability-inducing factor used. Collectively, we find that, due to its compatibility with small molecule antagonists and agonists, as well as siRNA, the ex vivo retina model constitutes a reliable tool to identify and study regulators and mechanisms of acute neurovascular permeability.

Targeting RGD-binding integrins as an integrative therapy for diabetic retinopathy and neovascular age-related macular degeneration

Integrins are a class of transmembrane receptors that are involved in a wide range of biological functions. Dysregulation of integrins has been implicated in many pathological processes and consequently, they are attractive therapeutic targets. In the ophthalmology arena, there is extensive evidence suggesting that integrins play an important role in diabetic retinopathy (DR), age-related macular degeneration (AMD), glaucoma, dry eye disease and retinal vein occlusion. For example, there is extensive evidence that arginyl-glycyl-aspartic acid (Arg-Gly-Asp; RGD)-binding integrins are involved in key disease hallmarks of DR and neovascular AMD (nvAMD), specifically inflammation, vascular leakage, angiogenesis and fibrosis. Based on such evidence, drugs that engage integrin-linked pathways have received attention for their potential to block all these vision-threatening pathways. This review focuses on the pathophysiological role that RGD-binding integrins can have in complex multifactorial retinal disorders like DR, diabetic macular edema (DME) and nvAMD, which are leading causes of blindness in developed countries. Special emphasis will be given on how RGD-binding integrins can modulate the intricate molecular pathways and regulate the underlying pathological mechanisms. For instance, the interplay between integrins and key molecular players such as growth factors, cytokines and enzymes will be summarized. In addition, recent clinical advances linked to targeting RGD-binding integrins in the context of DME and nvAMD will be discussed alongside future potential for limiting progression of these diseases.

Efficacy of Intravitreal Dexamethasone Implant in Different Patterns of Diabetic Macular Edema

PURPOSE

Different patterns of diabetic macular edema (DME) suggest different pathogenesis and drug response. We evaluated the outcomes after intravitreal dexamethasone (DEX) implant for DME with or without serous retinal detachment (SRD).

METHODS

In this retrospective study, 22 naïve patients (23 eyes) with DME who underwent a single DEX implant were evaluated. Based on the optical coherence tomographic pattern of DME, 12 eyes had a cystoid macular edema pattern (Group 1) and 11 eyes had an SRD pattern (Group 2). The best-corrected visual acuity (BCVA), central retinal thickness (СRТ), central retinal volume (CRV), SRD height (SRDh), and intraocular pressure (IOP) were recorded before and at two and four months after the treatment.

RESULTS

There were no significant differences between the groups regarding demographic, clinical data and outcomes at baseline. In Group 1, the CRT and CRV significantly decreased at two months (P = 0.002 and P = 0.01, respectively), while the BCVA significantly improved at four months (P = 0.03). In Group 2, the CRT and CRV significantly improved (P < 0.01 and P ≤ 0.01, respectively) during the follow-up period. At four months, both groups showed a recurrence of DME, Group 1 in particular (two-month CRT reduction, -149 ± 127 µm vs four-month CRT reduction, -72 ± 174 µm; P = 0.04). The mean reduction in CRV was significantly different at four months (Group 1, -0.49 ± 1.7 mm3 vs Group 2, -1.3 ± 1.3 mm3 ; P = 0.04). In Group 2, the SRDh significantly decreased at two (P = 0.01) and four months (P = 0.01). Four cases with elevated IOP were managed.

CONCLUSION

DEX implants were found to be effective in different patterns of DME. The SRD pattern may predict a longer-lasting morphologic efficacy.

Sub-clinical thickening of the fovea in diabetes and its relationship to glycaemic control: a study using swept-source optical coherence tomography

Background

Accumulation of multiple pockets of fluid at the fovea, as a complication of poor blood glucose control in diabetes, causes impairment of central vision. A new ability to demonstrate a pre-clinical phase of this maculopathy could be valuable, enabling diabetic individuals to be alerted to the need to improve their glycaemic control. This study aimed to use swept-source optical coherence tomography (SS-OCT) to measure foveal thickness and macular volume in diabetic individuals without cystoid macular oedema, and in non-diabetic individuals, and relate these measures to participants’ glycaemic control.

Methods

Centre point thickness (CPT) and total macular volume (TMV) were measured using SS-OCT (DRI OCT Triton™, Topcon, Tokyo, Japan). Participants’ glycosylated haemoglobin (HbA_1c) level was also assessed (A_1cNow®+ System, PTS Diagnostics, Indianapolis, IN, USA). The diabetic (n = 27) and non-diabetic (n = 27) groups were matched for age (p = 0.100) and sex (p = 0.414), and HbA_1c level differed between diabetic and non-diabetic groups (p < 0.0005). The diabetic group comprised type 1 (n = 7) and type 2 (n = 20) diabetic individuals who were matched for duration of diabetes (p = 0.617) and whose glycaemic control was similar (p = 0.814).

Results

Diabetic individuals had significantly higher CPT (t(37) = 3.859, p < 0.0005) than non-diabetic individuals. In the diabetic group, multiple linear regression analysis revealed a conspicuous relationship between CPT and HbA_1c level (β = 0.501, t(21) = 3.139, p = 0.005): there was a 19-μm increase in CPT for each 1% increase in HbA_1c level. This relationship was not present in the non-diabetic group (β = − 0.068, t(23) = − 0.373, p = 0.712).

Conclusions

SS-OCT is the only way to measure macular thickness in vivo. Diabetic individuals en bloc had higher CPT compared with non-diabetic individuals. Moreover, in the diabetic group, HbA_1c level significantly predicted CPT. Our results suggest that, in diabetes, sub-clinical thickening may occur at the fovea before cystoid macular oedema becomes clinically evident. This could provide diabetic individuals with an early warning of disease progression and motivate them to improve control of their diabetes, with a view to avoiding the need of intra-vitreal injections with their attendant risks.

Adherence of patients with diabetic macular oedema to intravitreal injections: A systematic review

The purpose of this study was to review adherence rates to intravitreal injections in the treatment of diabetic macula oedema and to identify factors associated with adherence. A systematic search of Embase, Medline, PsycINFO and CINAHL was conducted up to May 2020. Two authors independently screened, selected and appraised the studies. Seven articles on anti-VEGF treatment were found to meet the inclusion criteria. No studies were found on intravitreal corticosteroids or dexamethasone implants. Attendance rates varied between studies from 35% to 85%. The rate of missed or delayed attendance ranged from 14% to 51%, whereas 25% of patients were lost to follow-up at 12 months. Non-adherence was found to be multifactorial and included patient related reasons, demographic characteristics and clinical factors. Enablers to adherence included patient understanding of the disease and treatment. Further research in this area is warranted in order to better understand adherence in these patients and to improve patient outcomes.

Baseline SD-OCT characteristics of diabetic macular oedema patterns can predict morphological features and timing of recurrence in patients treated with dexamethasone intravitreal implants

AIMS

To evaluate the timing and spectral-domain optical coherence tomography (SD-OCT) features of diabetic macular oedema (DME) recurrence according to baseline OCT patterns in patients treated with dexamethasone implant (DEX-I).

METHODS

This is a retrospective observational study (72 eyes/65 patients). Best-corrected visual acuity, timing of DME recurrence, and SD-OCT pattern [intraretinal cysts (IRC), IRC plus subretinal fluid (mixed), external limiting membrane (ELM), ellipsoid (IS/OS) layer integrity] were assessed at baseline and monthly until first DME recurrence.

RESULTS

Forty-two (58.3%) and 30 (41.6%) DME eyes had an IRC and mixed DME pattern at baseline, respectively. Twenty-four out of thirty mixed eyes (80%) relapsed without subretinal fluid. At baseline, mixed eyes showed similar changes in ELM and IS/OS (60 and 76.6% of eyes, respectively) versus IRC eyes (42.8 and 80.9% of eyes). After DME recurrence, more mixed eyes at baseline showed ELM and IS/OS changes (63.3 and 86.6%) than IRC eyes (50 and 76.2%). 33.3% of mixed eyes had DME recurrence at ≥ 6 months from first DEX-I implant versus 19% of IRC eyes.

CONCLUSIONS

Mixed DME eyes were treated with DEX-I relapse later and more frequently without subretinal fluid than IRC eyes. SD-OCT characteristics of different DME patterns at baseline can predict morphological features and timing of DME recurrence.

Two Year Visual Acuity and Structural Outcomes in Patients with Diabetic Macular Oedema Treated with Intravitreal Aflibercept - A Retrospective Cohort Study

Purpose

To assess visual and anatomical outcomes of intravitreal aflibercept for clinically significant diabetic macular oedema (DME).

Methods

For this retrospective single-center cohort study at a tertiary referral center, we performed a data warehouse query to identify 117 treatment-naive patients (139 eyes) undergoing intravitreal treatment with aflibercept for DME between January 2014 and May 2018. Changes in best-corrected visual acuity (BCVA) values (as measured with ETDRS letters), central retinal thickness (CRT) and total macular volume (TVOL) are reported over a two-year period at various time-points.

Results

The total number of injections per study eye was 5.5 ± 1.4 after one and 8.7 ± 2.2 injections after two years. Baseline visual acuity (VA) was 60.1 ± 14.5 letters. A gain of 4.8 and 9.2 letters from baseline was observed after one and two years, respectively (both p ≤ 0.01). In comparison to the mean CRT at baseline (419 ± 174 µm), a CRT decrease was observed after one and two years of treatment (298 ± 115 µm and 319 ± 119 µm, respectively; both p ≤ 0.01). Similarly, TVOL decreased from 10.12 ± 2.05 mm³ to 8.96 ± 0.96 mm³ and 9.01 ± 1.29 mm³ (both p ≤ 0.01).

Conclusion

This study demonstrates that treating DME with intravitreal aflibercept yields positive functional and structural outcomes over a two-year period. However, we observed fewer injection numbers, along with inferior VA and structural outcomes than has been reported in randomized clinical trials. Our results show similar results as in patients treated with ranibizumab due to DME in real-life settings.

Intravitreal dexamethasone implant Ozurdex in the treatment of diabetic macular edema in patients not previously treated with any intravitreal drug: a prospective 12-month follow-up study

Objective: To evaluate the mid-long-term efficacy and safety of the dexamethasone intravitreal (DEX) implant (Ozurdex¹) in naïve patients with diabetic macular edema (DME).Methods: Prospective and single-center study conducted on consecutive patients with a diagnosis of DME, who received a DEX implant and were followed up for at least 12 months. The main outcomes measurements were the mean change in best corrected visual acuity (BCVA) and in foveal thickness (FT) as compared to the baseline values.Results: Of the 84 screened patients 50 were included in the study. The BCVA significantly improved from 52.4 (20.4) letters at baseline to 62.6 (15.6), 61.2 (18.4), 61.6 (18.6), 60.6 (19.0), and 60.6 (18.8) at 2, 4, 6, 12 months and end of follow-up period, respectively (repeated measures ANOVA and the Greenhouse-Geisser correction; p = .0008). At the end of the follow-up period, a gain of BCVA of ≥5, ≥10, and ≥15 letters were observed in 26 (52.0%), 18 (36.0%), and 16 (32.0%) patients, respectively. The mean FT was significantly reduced from 446.0 (139.9) µm at baseline to 327.2 (103.6) at the end of follow-up (repeated measures ANOVA and the Greenhouse-Geisser correction; p = .0008). During the study follow-up, the patients receive a mean of 3.4 (2.9-3.9) implants. Of the 32 phakic eyes at baseline, 17 (53.1%) either developed new lens opacity or progression of an existing opacity.Conclusion: In eyes with DME not previously treated with intravitreal drugs, DEX implants provide meaningful functional and anatomical benefits, and these results are sustained mid-long-term.

[Ranibizumab and aflibercept for diabetic macular edema-retrospective study with real-life data after 12 months]

BACKGROUND

Currently only few data are available on a direct comparison of the treatment reality with ranibizumab and aflibercept in patients with diabetic macular edema (DME). This study assessed best corrected visual acuity (BCVA) outcomes and central retinal thickness (CRT) under treatment with ranibizumab and aflibercept.

MATERIAL AND METHODS

Patients with DME involving the fovea in treatment-naïve eyes and a follow-up period of least 12 months were retrospectively identified. Patients underwent treatment with ranibizumab 0.5 mg or aflibercept 2.0 mg. The findings were obtained using clinical examination, fluorescein angiography and spectral domain optical coherence tomography (SD-OCT, measuring CRT).

RESULTS

A total of 41 treatment-naïve eyes were identified in 29 patients with DME involving the fovea. The mean 12-month improvement was +9.5 letters in 19 eyes treated with ranibizumab and BCVA improving from 0.57 log MAR (95% confidence interval, CI 0.45-0.70 log MAR) to 0.38 log MAR (95% CI 0.25-0.50 log MAR; p < 0.001) and +8.5 letters in the aflibercept group with 22 eyes and BCVA improving from 0.38 log MAR (95% CI 0.25-0.51 log MAR) to 0.21 log MAR (95% CI 0.08-0.34 log MAR; p < 0.001). The difference between the two groups was not statistically significant (p = 0.599). When the initial visual acuity was 0.4 or less, the mean BCVA improved in 14 eyes treated with ranibizumab from 0.62 log MAR (95% CI 0.47-0.79 log MAR) to 0.38 log MAR (95% CI 0.21-0.55 log MAR), an improvement of 12.0 letters (p < 0.001), in 11 eyes treated with aflibercept from 0.63 log MAR (95% CI 0.42-0.84 log MAR) to 0.29 log MAR (95% CI 0.08-0.50 log MAR), an improvement of 17.0 letters (p < 0.001). The difference between the two groups was significant (p < 0.001). The mean number of intravitreal injections was 6.4 (95% CI 5.1-7.7) in the ranibizumab group, 7.5 (95% CI 6.2-8.8) in the aflibercept group (p = 0.199). The mean CRT decreased significantly (p < 0.001) in patients treated with both ranibizumab and aflibercept without any evidence of a significant difference between the two groups (p = 0.514).

DISCUSSION

In the patients studied ranibizumab and aflibercept showed a good safety and efficacy in the treatment of DME regarding BCVA and CRT under real-life conditions after 12 months. In cases of lower initial visual acuity (0.4 or 20/50 or less) aflibercept was more effective at improving vision.

Association of urinary albumin excretion with central foveal thickness and intravitreal conbercept treatment frequency in patients with diabetic macular edema

AIM

To investigate the effect of albuminuria on diabetic macular edema (DME) and the possible association between baseline urinary albumin excretion (UAE) and intravitreal conbercept (IVC) treatment frequency in DME patients.

METHODS

In this hospital-based retrospective study, a total of 350 in-patients with type 2 diabetes mellitus were recruited and their clinical records were reviewed. Thereafter, 52 patients identified with severe non-proliferative diabetic retinopathy (NPDR) combined with albuminuria were divided into the microalbuminuria (UAE 30-300 mg/24h) and macroalbuminuria (UAE>300 mg/24h) groups, which were compared and analyzed by both independent sample t-test and Chi-square test. Correlations between the systemic variables and the central foveal thickness (CFT) were evaluated using Spearman's correlation and linear regression analyses. Of the 52 patients with center-involved DME, 43 received an initial combined injection of conbercept (0.5 mg/0.05 mL) and triamcinolone acetonide (1 mg/0.05 mL), followed by an IVC injection, as needed. The relationship between baseline UAE and number of IVC injections during the first year of treatment was analyzed using Spearman's partial correlation.

RESULTS

Of 350 patients, a higher incidence of DME was observed in severe non-proliferative retinopathy (NPDR) patients than that observed in other groups. By dividing the 52 patients with severe NPDR into the micro- and macro-albuminuria subgroups, significant differences in CFT, systolic blood pressure, total cholesterol and serum creatinine levels, and UAE were revealed. Furthermore, a positive liner correlation between the UAE and CFT was found. Finally, the partial correlation coefficient adjusted for either the CFT or UAE indicated that both parameters directly correlated with the number of IVC injections administered during the 12mo of follow-up.

CONCLUSION

Generally, macular edema occurred in patients with severe NPDR, for whom the UAE is an independent risk predictor of DME. The baseline UAE and CFT predicted the treatment frequency of IVC injections administered in the first year for eyes with DME.

Endomucin restores depleted endothelial glycocalyx in the retinas of streptozotocin-induced diabetic rats

Endothelial glycocalyx plays a significant role in the development and progression of diabetic complications. Endomucin (EMCN) is an anti-inflammatory membrane glycoprotein that is mainly expressed in venous and capillary endothelial cells. However, the function of EMCN in diabetic retinopathy (DR) progression is still completely unknown. We first investigated the change of EMCN expression in the retina and human retinal microvascular endothelial cells. We then overexpressed EMCN in the retina with adeno-associated virus and induced DR with streptozotocin (STZ). We analyzed EMCN's effect on the integrity of endothelial glycocalyx under conditions of DR. Furthermore, we investigated EMCN's protective effect against inflammation and blood-retinal barrier (BRB) destruction. We found that EMCN is specifically expressed in retinal endothelial cells and that its levels are decreased during hyperglycemia in vitro and in vivo. Overexpression of EMCN can restore the retinal endothelial glycocalyx of STZ-induced diabetic rats. Furthermore, EMCN overexpression can decrease leukocyte-endothelial adhesion to ameliorate inflammation and stabilize the BRB to inhibit vessel leakage in rats with DR. EMCN may protect patients with diabetes from retinal vascular degeneration by restoring the endothelial glycocalyx. EMCN may thus represent a novel therapeutic strategy for DR because it targets endothelial glycocalyx degradation associated with this disease.-Niu, T., Zhao, M., Jiang, Y., Xing, X., Shi, X., Cheng, L., Jin, H., Liu, K. Endomucin restores depleted endothelial glycocalyx in the retinas of streptozotocin-induced diabetic rats.

Primary outcomes of the VIDI study: phase 2, double-masked, randomized, active-controlled study of ASP8232 for diabetic macular edema

Background

ASP8232 is a potent and specific small molecule vascular adhesion protein-1 (VAP-1) inhibitor. This study evaluated the effect of ASP8232 on excess retinal thickness when given alone or in combination with ranibizumab in patients with center-involved diabetic macular edema (CI-DME).

Methods

This was a phase 2a, placebo and sham-injection controlled, double-masked, randomized, parallel-group clinical trial. Participants were patients with CI-DME and central subfield thickness (CST) ≥ 375 µm in the study eye as assessed by spectral domain optical coherence tomography. Eligible patients were randomized to (1) daily oral ASP8232 40 mg monotherapy; (2) combination therapy of daily oral ASP8232 40 mg and monthly intravitreal ranibizumab 0.3 mg; or (3) monthly intravitreal ranibizumab 0.3 mg monotherapy. The treatment period was 12 weeks. CST and best corrected visual acuity (BCVA) were assessed at baseline and at Weeks 2, 4, 8, 12, 16 and 24. The primary outcome was the mean percent change from baseline in excess CST at Week 12. Secondary outcomes were BCVA, safety and tolerability, and pharmacokinetic and pharmacodynamic characteristics of ASP8232.

Results

After 12 weeks, the mean (95% confidence interval) percent change in excess CST was 11.4% (− 15.0%, 37.8%) in the ASP8232 group, − 61.7% (− 86.1%, − 37.2%) in the ASP8232/ranibizumab group, and − 75.3% (− 94.8%, − 55.8%) in the ranibizumab group. The change from baseline in the two ranibizumab arms was statistically significant (P < 0.001) as was the difference between the ranibizumab groups and the ASP8232 group (P < 0.001). Mean (SD) increase in BCVA score from baseline was 3.1 (7.3) in the ASP8232 group, 5.2 (7.1) in the ASP8232/ranibizumab group, and 8.2 (9.5) in the ranibizumab group. The increase from baseline in BCVA score was statistically and clinically significant in the ranibizumab group compared with the ASP8232 group (P = 0.015). ASP8232 resulted in near complete inhibition of plasma VAP-1 activity whilst ranibizumab had no effect.

Conclusions

Near complete inhibition of plasma VAP-1 activity with ASP8232 had no effect on CST in patients with CI-DME. Furthermore, combination therapy did not provide additional benefit to treatment with ranibizumab alone, which significantly reduced CST and improved BCVA.

Trial registration clinicaltrials.gov; NCT02302079. Registered on November 26, 2014

Electronic supplementary material

The online version of this article (10.1186/s40942-019-0178-7) contains supplementary material, which is available to authorized users.

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.

Anti-vascular endothelial growth factor treatment for retinal conditions: a systematic review and meta-analysis

OBJECTIVES

To evaluate the comparative effectiveness and safety of intravitreal bevacizumab, ranibizumab and aflibercept for patients with choroidal neovascular age-related macular degeneration (cn-AMD), diabetic macular oedema (DMO), macular oedema due to retinal vein occlusion (RVO-MO) and myopic choroidal neovascularisation (m-CNV).

DESIGN

Systematic review and random-effects meta-analysis.

METHODS

Multiple databases were searched from inception to 17 August 2017. Eligible head-to-head randomised controlled trials (RCTs) comparing the (anti-VEGF) drugs in adult patients aged ≥18 years with the retinal conditions of interest. Two reviewers independently screened studies, extracted data and assessed risk of bias.

RESULTS

19 RCTs involving 7459 patients with cn-AMD (n=12), DMO (n=3), RVO-MO (n=2) and m-CNV (n=2) were included. Vision gain was not significantly different in patients with cn-AMD, DMO, RVO-MO and m-CNV treated with bevacizumab versus ranibizumab. Similarly, vision gain was not significantly different between cn-AMD patients treated with aflibercept versus ranibizumab. Patients with DMO treated with aflibercept experienced significantly higher vision gain at 12 months than patients receiving ranibizumab or bevacizumab; however, this difference was not significant at 24 months. Rates of systemic serious harms were similar across anti-VEGF agents. Posthoc analyses revealed that an as-needed treatment regimen (6-9 injections per year) was associated with a mortality increase of 1.8% (risk ratio: 2.0 [1.2 to 3.5], 2 RCTs, 1795 patients) compared with monthly treatment in cn-AMD patients.

CONCLUSIONS

Intravitreal bevacizumab was a reasonable alternative to ranibizumab and aflibercept in patients with cn-AMD, DMO, RVO-MO and m-CNV. The only exception was for patients with DME and low visual acuity (<69 early treatment diabetic retinopathy study [ETDRS] letters), where treatment with aflibercept was associated with significantly higher vision gain (≥15 ETDRS letters) than bevacizumab or ranibizumab at 12 months; but the significant effects were not maintained at 24 months. The choice of anti-VEGF drugs may depend on the specific retinal condition, baseline visual acuity and treatment regimen.

PROSPERO REGISTRATION NUMBER

CRD42015022041.

Aflibercept with adjuvant micropulsed yellow laser versus aflibercept monotherapy in diabetic macular edema

PURPOSE

To assess the impact of micropulsed laser (MPL) on modifying the number of aflibercept injections when used as an adjuvant therapy in diabetic macular edema (DME).

METHODS

A prospective randomized interventional clinical study included patients with DME attending Al Hadi Clinic, Kuwait, during the period from May 2017 to December 2018. Patients were allocated in two groups; group A received aflibercept injections alone and group B received combined aflibercept injections followed by MPL within a week. The primary outcome was the number of Aflibercept injections in each group guided by the change in central macular thickness (CMT). All the patients were followed for 18 months. Secondary outcome measures included best corrected visual acuity (BCVA), contrast sensitivity (CS), and any recorded complications.

RESULTS

Fifty-four eyes of 51 patients were included (27 in each group). There was no statistically significant difference between the two groups in baseline characteristics except for the age that was statistically higher in group B (p = 0.001). The number of injections were significantly lower in group B (4.1 ± 1.1) than group A (7.3 ± 1.1) (p < 0.005). At 18th month, there was significant reduction in CMT in both groups (p < 0.005) with no statistical difference between the two groups (p = 0.989). Final BCVA in both groups showed statistically significant improvement (p < 0.005) without statistically significant difference between the two groups (p = 0.082). In both groups, the CS showed significant improvement from baseline (p < 0.005). No ocular or systemic adverse effects were observed in either group.

CONCLUSION

Supplemental MPL in eyes with DME may decrease the burden of the aflibercept injection frequency while resulting in comparable anatomical and visual outcomes.

Correlations of blood lipids with early changes in macular thickness in patients with diabetes

PURPOSE

This study aimed to investigate the correlations of blood lipids with changes in macular volume and thickness in patients with diabetes.

METHODS

Central subfield macular thickness (CSMT) and central subfield macular volume (CSMV) were measured in 85 patients with type 2 diabetes (DM2) using spectral-domain optical coherence tomography (SD-OCT). In addition, serum creatinine (Cr), total cholesterol (TC), triglyceride (TG), high-density lipoprotein cholesterol (HDLC), low-density lipoprotein cholesterol (LDLC), glycated hemoglobin (HbA1c), and proteinuria were measured in all patients.

RESULTS

The mean CSMT of the 85 patients was 272.8±16.9μm, and CSMV was 215.1±14.6×10^-3mm³. TC, LDLC, HbA1c, and proteinuria were closely correlated to CSMT, and HDLC, HbA1c, and proteinuria were correlated to CSMV. After adjustment for sex, age, DM2 course, proteinuria, and HbA1c, LDLC was significantly correlated to CSMT (95% confidence interval (CI), 1.93-11.05, P=0.008) and CSMV (95% CI, 0.92-8.41, P=0.021); however, HDLC, TC, and TG showed no significant correlation with CSMT or CSMV.

CONCLUSIONS

Increased LDLC was closely correlated to changes in CSMT and CSMV in early diabetic patients, and increased CSMT was also accompanied by increased LDLC; therefore, this type of patient would be more likely to develop macular edema.

Intravitreal dexamethasone implant Ozurdex® in naïve and refractory patients with different subtypes of diabetic macular edema

Background

Diabetic macular edema (DME) can be treated with different alternatives, among them Dexamethasone intravitreal implant 0.7 mg (DEX 0.7) has demonstrated that may improve both central macular thickness (CMT) and best corrected visual acuity (BCVA). This study aimed to evaluate the effect of the intravitreal dexamethasone implant Ozurdex® in patients with different subtypes of diabetic macular edema over a 6-month follow-up period.

Methods

Eighty-four (29 naïve and 55 previously treated) eyes were included in this retrospective study. For each patient, the BCVA [Early Treatment Diabetic Retinopathy Study (ETDRS) charts] and macular thickness on optical coherence tomography (OCT) at baseline visit and within the 2nd, 4th, and 6th months of follow-up were obtained. The main outcomes measurements were the mean change in BCVA and in CMT with respect to the baseline value. The percentage of patients gaining ≥5 letters and ≥ 10 letters in BCVA was also analyzed. Results: A total of 84 eyes, 29 (34.5%) naïve and 55 (65.5%) non-naïve, from 69 patients were included in the study. BCVA at baseline was 58.8 (16.4) and 61.8 (11.6) in naïve and refractory patients, respectively, p = 0.4513. At every visit, BCVA significantly improved from baseline in naïve and non-naïve eyes (p < 0.0001 and p = 0.0003, respectively; Friedman rank sum test). At baseline, the mean CMT was 466.2 (189.7) μm and 448.1 (110.7) μm in the naïve and non-naïve patients, respectively (p = 0.5830); and decreased to 339.3 (92.5) μm and 357.5 (79.1) μm, respectively (p = 0.0004 and p < 0.0001, respectively, Wilcoxon signed-rank test). The proportion of patients gaining ≥10 letters was significantly greater in the naïve group, p = 0.0199.

Conclusion

The intravitreal dexamethasone implant (Ozurdex) is effective for the treatment of diabetic macular edema, even in refractory cases that have failed to respond to previous therapies.

Impacto orçamentário da incorporação de medicamentos para tratamento em segunda linha do edema macular diabético no SUS sob a perspectiva da Secretaria de Estado de Saúde de Minas Gerais, Brasil

Resumo: Os objetivos foram efetuar a análise do impacto orçamentário para a incorporação de segunda linha terapêutica com terapia antiangiogênica de aplicação intravítrea, para tratamento de edema macular diabético, no âmbito do Sistema Único de Saúde (SUS) em Minas Gerais, Brasil, discutindo sua viabilidade à luz do orçamento do estado. A análise do impacto orçamentário com método determinístico, segundo diretriz do Ministério da Saúde. Foram incluídos os pacientes com provável falha ao tratamento de primeira linha, num horizonte temporal de 5 anos para todas as tecnologias avaliadas. Incluíram-se na análise os medicamentos bevacizumabe (uso off-label), ranibizumabe e aflibercepte. As populações foram calculadas tanto por demanda aferida quanto por estimativa epidemiológica. Como análises de sensibilidade efetuaram-se: cenário com difusão de tecnologia mais lenta; cenário com a entrada de bevacizumabe e ranibizumabe biossimilares no mercado; cenário com a desconsideração da inflação no período. O impacto orçamentário incremental, de acordo com as estimativas de demanda aferida e epidemiológica, respectivamente, foi de R$ 69.493.906,95-R$ 473.226.278,78 para bevacizumabe; R$ 349.319.965,60-R$ 2.378.732.103,09 para ranibizumabe e R$543.867.485,47-R$ 3.703.524.490,16 para aflibercepte. Bevacizumabe foi a alternativa financeiramente mais viável em todos os cenários das estimativas e análises de sensibilidade. Estimou-se incremento próximo a 3%, comparando com o orçamento de 2016 (demanda aferida). Avalia-se que a incorporação é viável dentro do SUS em Minas Gerais, mas sujeita às prioridades da gestão. A discrepância de preços entre produtos de eficácia semelhante é intrigante e tema fértil para estudos futuros.

Pathological changes in the cellular structures of retina and choroidea in the early stages of alloxan-induced diabetes

AIM

To investigate the temporal sequence of pathological changes in the cellular structures of retina and choroidea in the early stages of diabetes in laboratory animals.

METHODS

Experimental type 1 diabetes was modeled by three intraperitoneal injections of an alloxan solution into 30 male nonlinear rats at 16 wk of age. The 30^th and 60^th days from the final alloxan injection were chosen as the endpoints. Light and electron microscopy and morphometric and immunohistochemical studies were performed on histological slices of eyeballs from experimental animals.

RESULTS

Diabetic disturbances progressed to 60 d of the experiment. Thus, in the retina, a partial destruction of photoreceptors accompanied by interstitial edema was observed. The morphometric analysis revealed a reduction in the thickness of the retina. A reduction in the number of blood vessels of the choroid with disturbances of the endothelial cells and the vascular walls and a persistent reduction in the number of melanocytes were observed. The number of proliferating Ki-67 positive cells decreased, and the number of macrophages increased with diabetes development.

CONCLUSION

The starting point in the development of destructive changes involves early reduction in the number of melanocytes of the choroidea and alterations in the retinal pigment epithelium.

Inhibition of stromal cell-derived factor-1α/CXCR4 signaling restores the blood-retina barrier in pericyte-deficient mouse retinas

In diabetic retinopathy (DR), pericyte dropout from capillary walls is believed to cause the breakdown of the blood-retina barrier (BRB), which subsequently leads to vision-threatening retinal edema. While various proinflammatory cytokines and chemokines are upregulated in eyes with DR, their distinct contributions to disease progression remain elusive. Here, we evaluated roles of stromal cell-derived factor-1α (SDF-1α) and its receptor CXCR4 in the BRB breakdown initiated by pericyte deficiency. After inhibition of pericyte recruitment to developing retinal vessels in neonatal mice, endothelial cells (ECs) upregulated the expression of SDF-1α. Administration of CXCR4 antagonists, or EC-specific disruption of the CXCR4 gene, similarly restored the BRB integrity, even in the absence of pericyte coverage. Furthermore, CXCR4 inhibition significantly decreased both the expression levels of proinflammatory genes (P < 0.05) and the infiltration of macrophages (P < 0.05) into pericyte-deficient retinas. Taken together, EC-derived SDF-1α induced by pericyte deficiency exacerbated inflammation through CXCR4 in an autocrine or paracrine manner and thereby induced macrophage infiltration and BRB breakdown. These findings suggest that the SDF-1α/CXCR4 signaling pathway may be a potential therapeutic target in DR.

The potent small molecule integrin antagonist THR-687 is a promising next-generation therapy for retinal vascular disorders

Integrins are associated with various eye diseases such as diabetic retinopathy (DR) and wet age-related macular degeneration (AMD) and implicated in main pathologic disease hallmarks like neovascularization, inflammation, fibrosis and vascular leakage. Targeting integrins has the potential to attenuate these vision-threatening processes, independent of anti-vascular endothelial growth factor (VEGF) responsiveness. The current investigation characterized THR-687 as a novel pan RGD (arginylglycylaspartic acid) integrin receptor antagonist able to compete for binding with the natural ligand with nanomolar potency (e.g. α_vβ₃ (IC₅₀ of 4.4 ± 2.7 nM), α_vβ₅ (IC₅₀ of 1.3 ± 0.5 nM) and α₅β₁ (IC₅₀ of 6.8 ± 3.2 nM)). THR-687 prevented the migration of human umbilical vein endothelial cells (HUVECs) into a cell-free area (IC₅₀ of 258 ± 113 nM) as well as vessel sprouting in an ex vivo mouse choroidal explant model (IC₅₀ of 236 ± 173 nM), and was able to induce the regression of pre-existing vascular sprouts. Moreover, combined intravitreal and intraperitoneal administration of THR-687 potently inhibited VEGF-induced leakage in the mouse retina. In addition, THR-687 injected intravitreally at 3 different dose levels (0.45 mg, 2.25 mg or 4.5 mg/eye) potently inhibited neovascularization-induced leakage in the cynomolgus laser-induced choroidal neovascularization (CNV) model. These data suggest that THR-687 is a promising drug candidate for the treatment of vision-threatening retinal vascular eye diseases such as DR and wet AMD.

Experiences and perceptions of patients undergoing treatment and quality of life impact of diabetic macular edema: a systematic review

Diabetic macular edema (DME) is a common cause of visual impairment. Current treatments for DME include laser photocoagulation, corticosteroids and Vascular Endothelial Growth Factor (VEGF) antagonists, which are administered via intravitreal injection. The purpose of this systematic review is to explore the experiences and perceptions of patients undergoing laser, corticosteroid implants and intravitreal injection treatment for DME and the impact on Quality of Life (QoL). A systematic search of the Embase, Medline, PsycINFO and Cinahl electronic databases was conducted to identify all studies with an unlimited date range, published in the English language, full text and incorporating human participants. Hand searching identified two articles. Following the application of the Critical Appraisal Skills Programme (CASP) Quantitative and Qualitative Research Checklist 21 articles were selected for inclusion, as they were deemed pertinent for the purpose of this review. Limited studies have examined DME patients' experiences and perceptions of treatment and QoL. The outcomes of these studies lack agreement on the effectiveness of treatment, treatment preferences and impact of QoL in patients with DME. Future research which enhances current knowledge will therefore serve to improve treatment outcomes and QoL in these patients.

Vision Outcomes Following Anti-Vascular Endothelial Growth Factor Treatment of Diabetic Macular Edema in Clinical Practice

PURPOSE

To determine monitoring and treatment patterns and vision outcomes in real-world patients initiating anti-vascular endothelial growth factor (anti-VEGF) therapy for diabetic macular edema (DME).

DESIGN

Retrospective interventional cohort study.

METHODS

Setting: Electronic medical record analysis of Geisinger Health System data.

STUDY POPULATION

A total of 110 patients (121 study eyes) initiating intravitreal ranibizumab or bevacizumab for DME during January 2007‒May 2012, with baseline corrected visual acuity of 20/40 to 20/320, and ≥1 ophthalmologist visit during follow-up.

MAIN OUTCOME MEASURES

Intravitreal injections per study eye during the first 12 months; corrected visual acuity, change in corrected visual acuity from baseline, proportions of eyes with ≥10 or ≥15 approximate Early Treatment Diabetic Retinopathy Study letter gain/loss at 12 months; number of ophthalmologist visits.

RESULTS

Over 12 months, mean number of ophthalmologist visits was 9.2; mean number of intravitreal injections was 3.1 (range, 1-12), with most eyes (68.6%) receiving ≤3 injections. At 12 months, mean corrected visual acuity change was +4.7 letters (mean 56.9 letters at baseline); proportions of eyes gaining ≥10 or ≥15 letters were 31.4% and 24.0%, respectively; proportions of eyes losing ≥10 or ≥15 letters were 10.8% and 8.3%, respectively. Eyes receiving adjunctive laser during the first 6 months (n = 33) showed similar change in corrected visual acuity to non-laser-treated eyes (n = 88) (+3.1 vs +5.3 letters at 12 months).

CONCLUSIONS

DME patients receiving anti-VEGF therapy in clinical practice undergo less frequent monitoring and intravitreal injections, and achieve inferior vision outcomes to patients in landmark clinical trials.

Management of diabetic macular edema with intravitreal dexamethasone implants: Expert recommendations using a Delphi-based approach

OBJECTIVES:

Despite being approved and effective, steroids, and especially dexamethasone intravitreal implants, still have a poorly-defined role in management of diabetic macular edema. In order to overcome some of the limitations in current recommendations, a group of experts met to define consensus on some of the most controversial issues on the use of dexamethasone intravitreal implants in daily management of diabetic macular edema.

METHODS:

A Delphi-based approach was utilized to develop clinically relevant statements applicable to routine treatment settings. A Steering Committee composed of four experts formulated 30 relevant statements, which were voted upon by a panel of 40 ophthalmologists/retinal specialists from across Italy.

RESULTS:

Dexamethasone intravitreal implants were considered to be a valid first-line alternative to treatment with an anti-vascular endothelial growth factor agent and should be the first choice in pseudophakic and vitrectomized patients. A Pro Re Nata regimen was felt to be appropriate for retreatment with dexamethasone intravitreal implants while a 6-month waiting period was not considered suitable. Among steroid treatments, dexamethasone intravitreal implants were considered to have the best ocular tolerability. In patients with persistent macular edema after the loading-phase treatment with an anti-vascular endothelial growth factor, consensus was reached that clinicians should consider switching therapy to dexamethasone intravitreal implants. Moreover, dexamethasone intravitreal implants can reduce the treatment burden for individuals who are not able to cope with the more intensive treatment regimen required by anti-vascular endothelial growth factor therapy.

CONCLUSIONS:

While further studies are needed, this survey provides some key recommendations for clinicians treating diabetic macular edema that may be useful when choosing dexamethasone intravitreal implants in daily practice.

The Role of Microglia in Diabetic Retinopathy: Inflammation, Microvasculature Defects and Neurodegeneration

Diabetic retinopathy is a common complication of diabetes mellitus, which appears in one third of all diabetic patients and is a prominent cause of vision loss. First discovered as a microvascular disease, intensive research in the field identified inflammation and neurodegeneration to be part of diabetic retinopathy. Microglia, the resident monocytes of the retina, are activated due to a complex interplay between the different cell types of the retina and diverse pathological pathways. The trigger for developing diabetic retinopathy is diabetes-induced hyperglycemia, accompanied by leukostasis and vascular leakages. Transcriptional changes in activated microglia, mediated via the nuclear factor kappa-light-chain-enhancer of activated B cells (NFκB) and extracellular signal–regulated kinase (ERK) signaling pathways, results in release of various pro-inflammatory mediators, including cytokines, chemokines, caspases and glutamate. Activated microglia additionally increased proliferation and migration. Among other consequences, these changes in microglia severely affected retinal neurons, causing increased apoptosis and subsequent thinning of the nerve fiber layer, resulting in visual loss. New potential therapeutics need to interfere with these diabetic complications even before changes in the retina are diagnosed, to prevent neuronal apoptosis and blindness in patients.

Current research into brain barriers and the delivery of therapeutics for neurological diseases: a report on CNS barrier congress London, UK, 2017

This is a report on the CNS barrier congress held in London, UK, March 22–23rd 2017 and sponsored by Kisaco Research Ltd. The two 1-day sessions were chaired by John Greenwood and Margareta Hammarlund-Udenaes, respectively, and each session ended with a discussion led by the chair. Speakers consisted of invited academic researchers studying the brain barriers in relation to neurological diseases and industry researchers studying new methods to deliver therapeutics to treat neurological diseases. We include here brief reports from the speakers.

Action on diabetic macular oedema: achieving optimal patient management in treating visual impairment due to diabetic eye disease

This paper identifies best practice recommendations for managing diabetes and sight-threatening diabetic eye disease. The authors provide an update for ophthalmologists and allied healthcare professionals on key aspects of diabetes management, supported by a review of the pertinent literature, and recommend practice principles for optimal patient management in treating visual impairment due to diabetic eye disease. In people with diabetes, early optimal glycaemic control reduces the long-term risk of both microvascular and macrovascular complications. The authors propose more can and should be done to maximise metabolic control, promote appropriate behavioural modifications and encourage timely treatment intensification when indicated to ameliorate diabetes-related complications. All people with diabetes should be screened for sight-threatening diabetic retinopathy promptly and regularly. It is shown that attitudes towards treatment adherence in diabetic macular oedema appear to mirror patients' views and health behaviours towards the management of their own diabetes. Awareness of diabetic macular oedema remains low among people with diabetes, who need access to education early in their disease about how to manage their diabetes to delay progression and possibly avoid eye-related complications. Ophthalmologists and allied healthcare professionals play a vital role in multidisciplinary diabetes management and establishment of dedicated diabetic macular oedema clinics is proposed. A broader understanding of the role of the diabetes specialist nurse may strengthen the case for comprehensive integrated care in ophthalmic practice. The recommendations are based on round table presentations and discussions held in London, UK, September 2016.

Diabetic retinopathy and the use of laser photocoagulation: is it cost-effective to treat early?

Background/aims

The aim of the study was to explore whether it would be cost-effective to apply panretinal photocoagulation (PRP) at the severe non-proliferative diabetic retinopathy (NPDR) (early treatment) stage, compared with waiting until high-risk proliferative diabetic retinopathy (HR-PDR) characteristics (deferred treatment) developed.

Methods

A Markov model with a 30-year time horizon was developed, in which patients presenting with moderate NPDR could progress through all stages of DR (severe NPDR>early PDR>HR-PDR>severe PDR) to severe vision loss and blindness (and to death). A National Health Service and personal social services perspective was adopted. Transition probabilities were mainly derived from the Early Treatment Diabetic Retinopathy Study. Health state utilities, costs and complications were based on information from the literature, supplemented by expert opinion. Costs and outcomes were discounted at 3.5%. Both deterministic and probabilistic sensitivity analyses were conducted.

Results

Administering PRP at the severe NPDR stage could be more effective and less costly than waiting until HR-PDR developed. Sensitivity analyses gave similar results, with early treatment continuing to dominate deferred treatment. The probabilistic sensitivity analysis suggests that at willingness-to-pay threshold of £20–£30 000 per quality-adjusted life year, the probability of early treatment being cost-effective is 60%.

Conclusion

PRP administered at the severe NPDR stage is likely to be cost-effective compared with delaying photocoagulation until HR-PDR develops. However, given the limitations of the evidence, these results need to be interpreted with caution. A trial of early versus deferred laser therapy is needed to provide better data based on modern treatments.

Diabetic retinopathy: current understanding, mechanisms, and treatment strategies

Diabetic retinopathy (DR) causes significant visual loss on a global scale. Treatments for the vision-threatening complications of diabetic macular edema (DME) and proliferative diabetic retinopathy (PDR) have greatly improved over the past decade. However, additional therapeutic options are needed that take into account pathology associated with vascular, glial, and neuronal components of the diabetic retina. Recent work indicates that diabetes markedly impacts the retinal neurovascular unit and its interdependent vascular, neuronal, glial, and immune cells. This knowledge is leading to identification of new targets and therapeutic strategies for preventing or reversing retinal neuronal dysfunction, vascular leakage, ischemia, and pathologic angiogenesis. These advances, together with approaches embracing the potential of preventative or regenerative medicine, could provide the means to better manage DR, including treatment at earlier stages and more precise tailoring of treatments based on individual patient variations.

Efficiency and safety of laser photocoagulation with or without intravitreal ranibizumab for treatment of diabetic macular edema: a systematic review and Meta-analysis

AIM

To compare the therapeutic effect and safety of laser photocoagulation along with intravitreal ranibizumab (IVR) versus laser therapy in treatment of diabetic macular edema (DME).

METHODS

Pertinent publications were identified through comprehensive searches of PubMed, EMBASE, Web of Science, Cochrane Library, and ClinicalTrials.gov to identify randomized clinical trials (RCTs) comparing IVR+laser to laser monotherapy in patients with DME. Therapeutic effect estimates were determined by weighted mean differences (WMD) of change from baseline in best corrected visual acuity (BCVA) and central retinal thickness (CRT) at 6, 12, or 24mo after initial treatment, and the risk ratios (RR) for the proportions of patients with at least 10 letters of improvement or reduction at 12mo. Data regarding major ocular and nonocular adverse events (AEs) were collected and analyzed. The Review Manager 5.3.5 was used.

RESULTS

Six RCTs involving 2069 patients with DME were selected for this Meta-analysis. The results showed that IVR+laser significantly improved BCVA compared with laser at 6mo (WMD: 6.57; 95% CI: 4.37-8.77; P<0.00001), 12mo (WMD: 5.46; 95% CI: 4.35-6.58; P<0.00001), and 24mo (WMD: 3.42; 95% CI: 0.84-5.99; P=0.009) in patients with DME. IVR+laser was superior to laser in reducing CRT at 12mo from baseline with statistical significance (WMD: -63.46; 95% CI: -101.19 to -25.73; P=0.001). The pooled RR results showed that the proportions of patients with at least 10 letters of improvement or reduction were in favor of IVR+laser arms compared with laser (RR: 2.13; 95% CI: 1.77-2.57; P<0.00001 and RR: 0.37; 95% CI: 0.22-0.62; P=0.0002, respectively). As for AEs, the pooled results showed that a significantly higher proportion of patients suffering from conjunctival hemorrhage (study eye) and diabetic retinal edema (fellow eye) in IVR+laser group compared to laser group (RR: 3.29; 95% CI: 1.53-7.09; P=0.002 and RR: 3.02; 95% CI: 1.24-7.32; P=0.01, respectively). The incidence of other ocular and nonocular AEs considered in this Meta-analysis had no statistical difference between IVR+laser and laser alone.

CONCLUSION

The results of our analysis show that IVR+laser has better availability in functional (improving BCVA) and anatomic (reducing CRT) outcomes than laser monotherapy for the treatment of DME. However, the patients who received the treatment of IVR+laser may get a higher risk of suffering from conjunctival hemorrhage (study eye) and diabetic retinal edema (fellow eye).

Fundamental principles of an anti-VEGF treatment regimen: optimal application of intravitreal anti-vascular endothelial growth factor therapy of macular diseases

BACKGROUND

Intravitreal anti-vascular endothelial growth factor (VEGF) therapy is now considered the gold standard for the treatment of various retinal disorders. As therapy has evolved, so too have the treatment regimens employed by physicians in clinical practice; however, visual outcomes observed in the real world have typically not reflected those reported in clinical trials. Possible reasons for this include a lack of consensus on treatment regimens and a lack of clarity about what the aims of treatment should be.

METHODS

The Vision Academy Steering Committee met to discuss the principles of an ideal treatment regimen, using evidence from the literature to substantiate each point. Literature searches were performed using the MEDLINE/PubMed database (cut-off date: March 2016) and restricted to English-language publications. Studies with fewer than ten patients were excluded from this review.

RESULTS

The Steering Committee identified the following four key principles for the ideal treatment regimen for anti-VEGF management of retinal diseases: 1. Maximize and maintain visual acuity (VA) benefits for all patients 2. Decide when to treat next, rather than whether to treat now 3. Titrate the treatment intervals to match patients' needs 4. Treat at each monitoring visit.

CONCLUSIONS

It is proposed that the adoption of a proactive and more personalized approach in the clinic such as a treat-and-extend regimen will lead to benefits for both the patient and the physician, through a reduction in the associated treatment burden and better utilization of clinic resources. Implementation of the four principles should also lead to better VA outcomes for each patient, with a minimized risk of vision loss.

The pathology associated with diabetic retinopathy

This review summarizes the pathological features of diabetic retinopathy. The lesions occurring in the diabetic retina have been described over many decades using descriptive and experimental approaches based on clinical studies on patients, human post-mortem material, animal models and various in vitro systems. We have also accumulated a wealth of knowledge about basic molecular mechanisms and key pathogenic processes that drive these abnormalities in diabetic retina. Despite these advances, there are still limited therapeutic options for diabetic retinopathy with those currently available only addressing late-stage disease. With a particular focus on the earlier stages of diabetes, there is growing appreciation the complex neuronal, glial and microvascular abnormalities which progressively disrupt retinal function. This is especially true from the perspective of the neurovascular unit during health and disease. Based on a strong appreciation of cellular and molecular pathology that underpins diabetic retinopathy, further advances are anticipated as we drive towards development of efficacious therapeutic options that can address all stages of disease.

Gene therapy for diabetic retinopathy: Are we ready to make the leap from bench to bedside?

Diabetic retinopathy (DR), a chronic and progressive complication of diabetes mellitus, is a sight-threatening disease characterized in the early stages by neuronal and vascular dysfunction in the retina, and later by neovascularization that further damages vision. A major contributor to the pathology is excess production of vascular endothelial growth factor (VEGF), a growth factor that induces formation of new blood vessels and increases permeability of existing vessels. Despite the recent availability of effective treatments for the disease, including laser photocoagulation and therapeutic VEGF antibodies, DR remains a significant cause of vision loss worldwide. Existing anti-VEGF agents, though generally effective, are limited by their short therapeutic half-lives, necessitating frequent intravitreal injections and the risk of attendant adverse events. Management of DR with gene therapies has been proposed for several years, and pre-clinical studies have yielded enticing findings. Gene therapy holds several advantages over conventional treatments for DR, such as a longer duration of therapeutic effect, simpler administration, the ability to intervene at an earlier stage of the disease, and potentially fewer side-effects. In this review, we summarize the current understanding of the pathophysiology of DR and provide an overview of research into DR gene therapies. We also examine current barriers to the clinical application of gene therapy for DR and evaluate future prospects for this approach.