Diabetic retinopathy: research to clinical practice

Non-invasive blood glucose monitoring technology in diabetes management: review

Diabetes is one of the leading non-communicable diseases globally, adversely impacting an individual's quality of life and adding a considerable burden to the healthcare systems. The necessity for frequent blood glucose (BG) monitoring and the inconveniences associated with self-monitoring of BG, such as pain and discomfort, has motivated the development of non-invasive BG approaches. However, the current research progress is slow, and only a few BG self-monitoring devices have made considerable progress. Hence, we evaluate the available non-invasive glucose monitoring technologies validated against BG recordings to provide future research direction to design, develop, and deploy self-monitoring of BG with integrated emerging technologies. We searched five databases, Embase, MEDLINE, Proquest, Scopus, and Web of Science, to assess the non-invasive technology's scope in the diabetes management paradigm published from 2000 to 2020. A total of three approaches to non-invasive screening, including saliva, skin, and breath, were identified and discussed. We observed a statistical relationship between BG measurements obtained from non-invasive methods and standard clinical measures. Opportunities exist for future research to advance research progress and facilitate early technology adoption for healthcare practice. The results promise clinical validity; however, formulating regulatory guidelines could foresee the deployment of approved non-invasive BG monitoring technologies in healthcare practice. Further, research prospects are there to design, develop, and deploy integrated diabetes management systems with mobile technologies, data analytics, and the internet of things (IoT) to deliver a personalised monitoring system.

Glucagon-like peptide-1 receptor agonists and diabetic retinopathy: nationwide cohort and Mendelian randomization studies

BACKGROUND

The ability of glucagon-like peptide-1 receptor agonists (GLP-1 RAs) to decrease certain microvascular events has called for the investigation of GLP-1 RAs against diabetic retinopathy (DR), but the evidence is limited. By combining data from observational and Mendelian randomization (MR) studies, we aimed to investigate whether GLP-1 RAs decrease the risk of DR.

METHODS

We combined data from several Swedish Registers and identified patients with incident type 2 diabetes being treated with GLP-1 RAs between 2006 and 2015, and matched them to diabetic patients who did not use GLP-1 RAs as the comparisons. The Cox proportional hazards models were applied to assess the risk of DR. We further performed the summary-data-based MR (SMR) analyses based on the Genotype-Tissue Expression databases and the Genome-Wide Association Study of DR from the FinnGen consortium.

RESULTS

A total of 2390 diabetic patients were treated with GLP-1 RAs and the incidence of DR was 5.97 per 1000 person-years. Compared with diabetic patients who did not use GLP-1 RAs having an incidence of 12.85 per 1000 person-years, the adjusted hazard ratio (HR) of DR was 0.42 [95% confidence interval (CI), 0.29-0.61]. Genetically-predicted GLP1R expression (the target of GLP-1 RAs) showed an inverse association with background [odds ratio (OR)=0.83, 95% CI, 0.71-0.97] and severe nonproliferative DR (OR=0.72, 95% CI, 0.53-0.98), and a non-significant association with overall (OR=0.97, 95% CI, 0.92-1.03) and proliferative DR (OR=0.98, 95% CI, 0.91-1.05).

CONCLUSIONS

Both observational and mendelian randomization analyses showed a significantly lower risk of DR for patients treated with GLP-1 RAs, which calls for further studies to validate these findings.

An Assessment on the Awareness of Diabetic Retinopathy Among Participants Attending the Diabetes Awareness Camp in Saudi Arabia

Aim The objective of this study is to assess the level of awareness of the effect of diabetes and diabetic retinopathy (DR) on the eye among a sample of the Jeddah community. Methods A cross-sectional study was conducted among those attending a diabetes awareness camp in Jeddah, Saudi Arabia, in November 2021. Participants were asked to answer questions in a structured questionnaire that was already used in a previous study. Responses were analyzed using Statistical Package for the Social Sciences (SPSS) version 25 (IBM SPSS Statistics, Armonk, NY, USA). Results A total of 352 participants were included in this study, 184 (52.3%) of them were females. Of the participants, only 74 (21%) had diabetes mellitus (DM). The vast majority (94%) of the participants believed that diabetes could affect the eyes, and 94.3% believed that maintaining the level of blood sugar could maintain the eye and the level of vision. Moreover, 77.3% were aware that diabetes could lead to visual impairment and blindness. Around one-third of the total participants and less than half of the diabetic group were found familiar with DR. Although 96% of diabetic participants reported the need for diabetics to get their eyes checked annually, only 70% did so. Lack of awareness of the effect of diabetes on the retina was the main barrier preventing diabetic groups from getting their eye checked. Conclusion Despite the good level of awareness among the community and diabetics about diabetes and its effect on the eyes, there is less awareness that DR is one of the most dangerous complications that lead to visual impairments. These findings assure the importance to raise awareness of DR among the community and diabetics and increase awareness of the importance of annual eye examinations.

Sociodemographic variables associated with risk for diabetic retinopathy

BACKGROUND

Several systemic and sociodemographic factors have been associated with the development and progression of diabetic retinopathy (DR). However, there is limited investigation of the potential role sociodemographic factors may play in augmenting systemic risk factors of DR. We hypothesize that age, sex, race, ethnicity, income, and insurance payor have an impact on hemoglobin A1c (HbA1c), body mass index, and systolic blood pressure, and therefore an upstream effect on the development of DR and vision-threatening forms of DR (VTDR).

METHODS

Multivariable analysis of longitudinal electronic health record data at a large academic retina clinic was performed. Sociodemographic factors included race, ethnicity, income, and insurance payor. Systemic risk factors for DR included hemoglobin A1c (HbA1c), systolic blood pressure (SBP), and body mass index (BMI). VTDR was identified from encounter diagnostic codes indicating proliferative retinopathy or diabetic macular edema. Patient-reported primary address zip codes were used to approximate income level, stratified into quartiles.

RESULTS

From 2016 to 2018, 3,470 patients with diabetes totaled 11,437 visits were identified. Black patients had higher HbA1c and SBP compared to White patients. White patients had higher BMI and SBP compared to patients of unknown/other race and greater odds of VTDR than the latter. Patients of Hispanic ethnicity had significantly higher SBP than non-Hispanic patients. Low-income patients had higher BMI and SBP than high-income patients and greater odds of VTDR than the latter. Medicaid recipients had greater odds of VTDR than those with Blue Care Network (BCN) and Blue Cross Blue Shield (BCBS) insurance. Medicaid and Medicare recipients had higher SBP compared to BCBS recipients. Finally, both higher HbA1c and SBP had greater odds of VTDR. There were no differences in odds of VTDR between White and Black patients or between Hispanic and non-Hispanic patients.

CONCLUSION

Significant associations exist between certain sociodemographic factors and well-known risk factors for DR. Income and payor were associated with increased severity of systemic risk factors and presence of VTDR. These results warrant further investigation of how risk factor optimization and disease prevention may be further improved by targeted intervention of these modifiable sociodemographic factors.

Effect of the COVID-19 Pandemic Lockdown on the Management of Diabetic Retinopathy: A Cross-Sectional Study

Introduction

Worldwide, diabetic retinopathy (DR) is one of the leading causes of vision loss. Early treatment and screening for DR have a major role in reducing the rate of the disease and the coronavirus disease 2019 (COVID-19) pandemic-related restrictions have altered real-world practice patterns in managing DR.

Aims and objectives

To evaluate the impact of the COVID-19 pandemic on the management of DR amongst patients presenting to a tertiary eye care center in Gujarat, India.

Methods

This is a cross-sectional study comparison of ophthalmic findings of 72 patients who presented to a tertiary care hospital with the manifestation of DR before and after the COVID-19 outbreak and subsequent lockdown. All the patients underwent detailed ophthalmic examinations, including optical coherence tomography (OCT) and fundus fluorescein angiography (FFA).

Results

The mean age of participants was 54.5 years, with the mean duration of diabetes being five years since first detected. Diabetes was present in 26 patients out of 72. The number of follow-up visits to an ophthalmologist before COVID-19 was at least every one to three months, which significantly decreased after the lockdown of COVID-19. We found a significant progression of DR and clinically significant macular edema (CSME) in patients with diabetes. Before COVID-19, there were two mild non-proliferative diabetic retinopathy (NPDR), seven moderate NPDR, 15 severe NPDR, and 15 very severe NPDR, which were increased post lockdown to three, nine, 27, and 21, respectively. The proliferative diabetic retinopathy (PDR) vitreous hemorrhage (VH) and tractional retinal detachment (TRD) were also increased to 12 after lockdown as compared to only six before the COVID-19 lockdown. The causes for progression are inability to attend regular check-ups, inability to take proper treatment of diabetes and DR, poor control of diabetes, episode of COVID-19, history of high dose of steroid use, poor kidney function, and not knowing that there is a progression of the disease. A common reason for not visiting an ophthalmologist was fear of the unknown due to COVID-19.

Conclusions

COVID-19 has severely impacted the routine follow-up of DR and, in the subsequent years, there might be an increased incidence of severe outcomes due to DR. The second wave of COVID-19 and its lockdown have had very significant effects on the visual outcome of untreated DR patients.

Balancing Data through Data Augmentation Improves the Generality of Transfer Learning for Diabetic Retinopathy Classification

The incidence of diabetes in Mauritius is amongst the highest in the world. Diabetic retinopathy (DR), a complication resulting from the disease, can lead to blindness if not detected early. The aim of this work was to investigate the use of transfer learning and data augmentation for the classification of fundus images into five different stages of diabetic retinopathy. The five stages are No DR, Mild nonproliferative DR, Moderate nonproliferative DR, Severe nonproliferative DR and Proliferative. To this end, deep transfer learning and three pre-trained models, VGG16, ResNet50 and DenseNet169, were used to classify the APTOS dataset. The preliminary experiments resulted in low training and validation accuracies, and hence, the APTOS dataset was augmented while ensuring a balance between the five classes. This dataset was then used to train the three models, and the best three models were used to classify a blind Mauritian test datum. We found that the ResNet50 model produced the best results out of the three models and also achieved very good accuracies for the five classes. The classification of class-4 Mauritian fundus images, severe cases, produced some unexpected results, with some images being classified as mild, and therefore needs to be further investigated.

Mechanistic Pathogenesis of Endothelial Dysfunction in Diabetic Nephropathy and Retinopathy

Diabetic nephropathy (DN) and diabetic retinopathy (DR) are microvascular complications of diabetes. Microvascular endothelial cells are thought to be the major targets of hyperglycemic injury. In diabetic microvasculature, the intracellular hyperglycemia causes damages to the vascular endothelium, via multiple pathophysiological process consist of inflammation, endothelial cell crosstalk with podocytes/pericytes and exosomes. In addition, DN and DR diseases development are involved in several critical regulators including the cell adhesion molecules (CAMs), the vascular endothelial growth factor (VEGF) family and the Notch signal. The present review attempts to gain a deeper understanding of the pathogenesis complexities underlying the endothelial dysfunction in diabetes diabetic and retinopathy, contributing to the development of new mechanistic therapeutic strategies against diabetes-induced microvascular endothelial dysfunction.

Investigation on the Q-markers of Bushen Huoxue Prescriptions for DR treatment based on chemometric methods and spectrum-effect relationship

ETHNOPHARMACOLOGICAL RELEVANCE

Diabetic retinopathy (DR) is a kind of complex complication of late diabetes mellitus with high incidence and risk of blindness. Bushen Huoxue Prescription (BHP), which consists of Rehmanniae radix (RR), Salviae miltiorrhizae radix et rhizoma (SMRR), Ginseng radix et rhizome (GRR) and Puerariae lobatae radix (PLR), has an active effect on the treatment of DR. However, the quality markers (Q-markers) of BHP are not entirely clear.

PURPOSE

This study aimed to screen the Q-markers of BHP for DR treatment based on the establishment of spectrum-effect relationship and verified experiment.

MATERIALS AND METHODS

In this study, 12 BHP samples (S1-S12) for fingerprint analysis and pharmacological evaluation were prepared according to a four-factor and twelve-level uniform design. High performance liquid chromatography-ultraviolet detector-evaporative light scattering detector (HPLC-UV-ELSD) was employed to analyze the fingerprint on the basis of the characteristics of BHP components. The evaluation of sample similarity was carried out by similarity analysis (SA) and hierarchical cluster analysis (HCA). The pharmacological indicators, including expression of vascular endothelial growth factor (VEGF) and hypoxia-inducible factor-1α (HIF-1α) in the retina of Sprague Dawley (SD) rats induced by streptozotocin (STZ), were detected by enzyme-linked immunosorbent assay (ELISA). Besides, the spectrum-effect relationship between common peaks of fingerprints and the pharmacological results was investigated by partial least squares regression (PLSR) and canonical correlation analysis (CCA). The results of spectrum-effect relationship were verified by the expression of VEGF and HIF-1α on primary culture retinal Müller cells induced by hyperglycemia and hypoxia.

RESULTS

In the HPLC-UV-ELSD fingerprint, 23 common peaks in UV and 14 common peaks in ELSD were identified. The pharmacological results indicated that the expression of VEGF and HIF-1α in the retina of SD rats was inhibited by 12 BHP samples to varying degrees compared with the model group. Based on SA and heatmap of HCA, S4 and S8 were clearly distinguished from other samples. The results of PLSR and CCA revealed that the contents of puerarin, daidzin, salvianolic acid B and ginsenoside Rb1 were inversely correlated with the expression of VEGF and HIF-1α. Hence, the four compounds may be the main active components to prevent and treat DR. The results of intervention on primary culture retinal Müller cells showed that puerarin, daidzin, salvianolic acid B, and ginsenoside Rb1 can significantly inhibit the expression of VEGF and HIF-1α.

CONCLUSIONS

The spectrum-effect relationship of BHP was successfully established, and the Q-markers of BHP for the prevention and treatment of DR were preliminarily confirmed. It provides a feasible method for the research of quality control.

White Matter Microstructural Abnormalities of the Visual Pathway in Type 2 Diabetes Mellitus: A Generalized Q-sampling Imaging Study

RATIONALE AND OBJECTIVES

Neurodegeneration is an early event in the pathogenesis of diabetic retinopathy (DR). We assessed the white matter microstructural integrity of the visual pathway in diabetes patients vs. healthy subjects, and investigated the advantages of generalized Q-sampling imaging (GQI) in the assessment of the visual pathway.

MATERIALS AND METHODS

T1-weighted, T2-weighted fluid-attenuated inversion recovery, and simultaneous multislice- diffusion sequences were acquired from 21 DR patients, 29 diabetes patients without DR (NDR group), and 28 age- and gender-matched healthy controls. Diffusion source images were reconstructed to GQI. Region of interest (ROI)-based analysis was utilized to evaluate microstructural alterations in the visual pathway. Multivariate linear regression analysis (forward stepwise method) was performed to investigate associations between clinical data and mean GQI parameters.

RESULTS

ROI-based analyses indicated that the GQI parameters generalized fractional anisotropy, quantitative anisotropy (QA), and normalized QA (NQA) were significantly lower in the NDR group than in the healthy controls, and even lower in the DR group than in the NDR group. Disease duration was significantly and negatively correlated with mean generalized fractional anisotropy and mean NQA.

CONCLUSION

GQI could sensitively and non-invasively evaluate the visual pathway in diabetes patients. The nerve fibers of the visual pathway were damaged before the onset of retinopathy, and this damage was aggravated after retinopathy onset, as a consequence of long exposure to hyperglycemia.

The Related Risk Factors of Diabetic Retinopathy in Elderly Patients with Type 2 Diabetes Mellitus: A Hospital-Based Cohort Study in Taiwan

Diabetic retinopathy (DR), caused by small vessel disease, is the main cause of blindness in persons with diabetes. Taiwan is one of the Asian countries with the highest prevalence rate of DR. The purpose was to investigate the related risk factors of DR in elderly patients with type 2 diabetes mellitus (T2DM), in Lee's Endocrinology Clinic. 792 T2DM patients over 60 years old were invited to have an outpatient visit at least every three months, and all of them were asked to undergo a standardized interview and collect their blood samples. Significant factors were being female (adjusted hazard ratio (HR): 1.287; 95% CI, 1.082-1.531), higher glycated hemoglobin (HbA1c) (HR: 1.067; 95% CI: 1.016-1.119), higher mean low density of lipoprotein cholesterol (LDL-c) (HR: 1.004; 95% CI: 1.001-1.006), and chewing betel nut (HR: 1.788; 95% CI: 1.362-2.347). This study showed that gender, the behavior of chewing betel nut, HbA1c, and LDL-c are important factors for the development of DR in elderly patients with T2DM. It is suggested that patients should control their HbA1c and LDL-c and quit chewing betel nut to prevent DR. This suggestion applies especially to female patients.

Regulation of blood-retinal barrier cell-junctions in diabetic retinopathy

Loss of the blood-retinal barrier (BRB) integrity and subsequent damage to the neurovascular unit in the retina are the underlying reasons for diabetic retinopathy (DR). Damage to BRB eventually leads to severe visual impairment in the absence of prompt intervention. Diabetic macular edema and proliferative DR are the advanced stages of the disease where BRB integrity is altered. Primary mechanisms contributing to BRB dysfunction include loss of cell-cell barrier junctions, vascular endothelial growth factor, advanced glycation end products-induced damage, and oxidative stress. Although much is known about the involvement of adherens and tight-junction proteins in the regulation of vascular permeability in various diseases, there is a significant gap in our knowledge on the junctional proteins expressed in the BRB and how BRB function is modulated in the diabetic retina. In this review article, we present our current understanding of the molecular composition of BRB, the changes in the BRB junctional protein turnover in DR, and how BRB functional modulation affects vascular permeability and macular edema in the diabetic retina.

Gene Therapy Intervention in Neovascular Eye Disease: A Recent Update

Aberrant growth of blood vessels (neovascularization) is a key feature of severe eye diseases that can cause legal blindness, including neovascular age-related macular degeneration (nAMD) and diabetic retinopathy (DR). The development of anti-vascular endothelial growth factor (VEGF) agents has revolutionized the treatment of ocular neovascularization. Novel proangiogenic targets, such as angiopoietin and platelet-derived growth factor (PDGF), are under development for patients who respond poorly to anti-VEGF therapy and to reduce adverse effects from long-term VEGF inhibition. A rapidly advancing area is gene therapy, which may provide significant therapeutic benefits. Viral vector-mediated transgene delivery provides the potential for continuous production of antiangiogenic proteins, which would avoid the need for repeated anti-VEGF injections. Gene silencing with RNA interference to target ocular angiogenesis has been investigated in clinical trials. Proof-of-concept gene therapy studies using gene-editing tools such as CRISPR-Cas have already been shown to be effective in suppressing neovascularization in animal models, highlighting the therapeutic potential of the system for treatment of aberrant ocular angiogenesis. This review provides updates on the development of anti-VEGF agents and novel antiangiogenic targets. We also summarize current gene therapy strategies already in clinical trials and those with the latest approaches utilizing CRISPR-Cas gene editing against aberrant ocular neovascularization.

Building on the success of anti-vascular endothelial growth factor therapy: a vision for the next decade

This article aims to identify key opportunities for improvement in the diagnosis and treatment of retinal disease, and describe recent innovations that will potentially facilitate improved outcomes with existing intravitreal vascular endothelial growth factor (VEGF) therapies and lay the groundwork for new treatment approaches. The review begins with a summary of the key discoveries that led to the development of anti-VEGF therapies and briefly reviews their impact on clinical practice. Opportunities for improvements in diagnosis, real-world outcomes with existing therapies, long-acting therapeutics and personalised health care are discussed, as well as the need to identify new targets for therapeutic intervention. Low-cost, remote patient screening and monitoring using artificial intelligence (AI)-based technologies can help improve diagnosis rates and enable remote disease monitoring with minimal patient burden. AI-based tools can be applied to generate patient-level prognostic data and predict individual treatment needs, reducing the time needed to optimise a patient’s treatment regimen. Long-acting therapeutics can help improve visual outcomes by reducing the treatment burden. When paired with AI-generated prognoses, long-acting therapeutics enable the possibility of vision loss prevention. Dual-acting drugs may help improve efficacy and/or durability beyond what is possible with anti-VEGF agents alone. Recent developments and ongoing innovations will help build upon the success of anti-VEGF therapies to further reduce vision loss owing to retinal disease while lowering the overall burden of care.

Eicosanoids and Oxidative Stress in Diabetic Retinopathy

Oxidative stress is an important factor to cause the pathogenesis of diabetic retinopathy (DR) because the retina has high vascularization and long-time light exposition. Cyclooxygenase (COX), lipoxygenase (LOX), and cytochrome P450 (CYP) enzymes can convert arachidonic acid (AA) into eicosanoids, which are important lipid mediators to regulate DR development. COX-derived metabolites appear to be significant factors causative to oxidative stress and retinal microvascular dysfunction. Several elegant studies have unraveled the importance of LOX-derived eicosanoids, including LTs and HETEs, to oxidative stress and retinal microvascular dysfunction. The role of CYP eicosanoids in DR is yet to be explored. There is clear evidence that CYP-derived epoxyeicosatrienoic acids (EETs) have detrimental effects on the retina. Our recent study showed that the renin-angiotensin system (RAS) activation augments retinal soluble epoxide hydrolase (sEH), a crucial enzyme degrading EETs. Our findings suggest that EETs blockade can enhance the ability of RAS blockade to prevent or mitigate microvascular damage in DR. This review will focus on the critical information related the function of these eicosanoids in the retina, the interaction between eicosanoids and reactive oxygen species (ROS), and the involvement of eicosanoids in DR. We also identify potential targets for the treatment of DR.

A novel interaction between soluble epoxide hydrolase and the AT1 receptor in retinal microvascular damage

Clinical studies have suggested that the renin-angiotensin system (RAS) may be a promising therapeutic target in treating diabetic retinopathy (DR). While AT1 receptor blockade decreased the incidence of DR in the DIRECT trial, it did not reduce the DR progression. Lack of understanding of the molecular mechanism of retinal microvascular damage induced by RAS is a critical barrier to the use of RAS blockade in preventing or treating DR. The purpose of this study is to investigate the interaction between soluble epoxide hydrolase (sEH) and the AT1 receptor in Angiotensin II (Ang II)- and diabetes-induced retinal microvascular damage. We demonstrate that Ang II increases retinal sEH levels, which is blunted by an AT1 blocker; administration of 11,12-epoxyeicosatrienoic acid (EET) exacerbates intravitreal Ang II-induced retinal albumin leakage; while sEH knockout (KO) and blockade reduce Ang II-induced retinal vascular remodeling, sEH KO causes retinal vascular leakage in Ang II-sEH KO mice; and sEH KO potentiates diabetes-induced retinal damage via promoting retinal vascular endothelial growth factor (VEGF) but reducing expression of tight junction proteins (ZO-1 and occludin). Our studies hold the promise of providing a new strategy, the use of combined EETs blockade with AT1 blocker, to prevent or reduce DR.

The Veterans Affairs Continuous Positive Airway Pressure Use and Diabetic Retinopathy Study

SIGNIFICANCE

Obstructive sleep apnea has been linked to the development and progression of diabetic retinopathy. In this study, diabetic patients compliant with continuous positive airway pressure therapy (CPAP) for sleep apnea were less likely to have retinopathy, emphasizing the benefits and potential therapeutic role of CPAP in individuals with both conditions.

PURPOSE

The aim of this study was to compare the prevalence of diabetic retinopathy in type 2 diabetic patients with obstructive sleep apnea who were compliant with CPAP therapy with those who were not compliant with CPAP therapy.

METHODS

A retrospective cross-sectional review of type 2 diabetic patients using CPAP for obstructive sleep apnea was conducted. The prevalence of retinopathy was identified, and groups with and without retinopathy were compared using univariate analyses and multivariate logistic regression.

RESULTS

The prevalence of retinopathy was 19.6% (n = 321). Retinopathy was significantly less prevalent in those compliant with CPAP (odds ratio, 0.54; 95% confidence interval, 0.31 to 0.94; P = .04). The relationship remained statistically significant when adjusting for other factors known to impact the course of diabetic eye disease.

CONCLUSIONS

Increased CPAP compliance may mitigate the risk of developing diabetic retinopathy in type 2 diabetic patients with obstructive sleep apnea.

Intravitreal bevacizumab improves the clearance of vitreous haemorrhage and visual outcomes in patients with proliferative diabetic retinopathy

Objective

To evaluate the occurrence of vitreous haemorrhage (VH) secondary to proliferative diabetic retinopathy (PDR) and the efficacy of intravitreal bevacizumab (IVB) for VH in 5-year real-life data.

Methods and analysis

850 adult patients with type 1 (T1D) or type 2 diabetes (T2D) with PDR were screened for VH. The effect of IVB was evaluated by the clearage of VH and the change in best corrected visual acuity (BCVA). The rates of VHs, reinjections, macular oedema, complications, additional treatments and outcomes of spontaneous resorption, panretinal photocoagulation or pars plana vitrectomy (PPV) for VH were also investigated.

Results

VH occurred in 16% of patients with T1D and 9% of patients with T2D with PDR. 336 VHs in 140 eyes of 103 patients were documented. VH was cleared in 92% of cases in less than 3 months by the initial IVB. IVB was superior to other treatment methods in shortening the time for clearance of VH (Kaplan-Meier, p<0.0001). The average rate of IVB reinjections was 1.7±1.1 and the reinjection interval was 7.2±3.9 weeks. BCVA increased 0.73±0.04 logarithm of the minimum angle of resolution units after IVB (generalised estimating equations, p=0.0004). In 5 years, the patients had 2.2±2.7 recurrence of VHs. A simultaneous 72% decrease in the rate of PPVs was documented (p<0.0001).

Conclusion

VH occurs mostly in patients with T1D. The therapeutic effect of IVB for VH was significant and led to improved clearance of VH and visual outcome. Moreover, IVB prevented persistent and recurrent VHs and decreased the need for costly PPV.

Pharmacotherapy for metabolic and cellular stress in degenerative retinal diseases

Retinal photoreceptors continually endure stresses associated with prolonged light exposure and the metabolic demands of dark adaptation. Although healthy photoreceptors are able to withstand these stresses for several decades, the disease-affected retina functions at a reduced capacity and is at an increased risk for dysfunction. To alleviate cellular and metabolic stressors in degenerative retinal diseases, a new class of drugs that modulate the metabolic activity of the retina have been developed. A clinical candidate in this class (emixustat) has been shown to reduce retinal pathology in various animal models of human retinal disease and is currently under clinical study. Here, we describe the pharmacological properties of emixustat, its mechanisms of action, and potential for use in the treatment of specific retinal diseases.

Impact of Diabetic Retinopathy on Sleep, Mood, and Quality of Life

Purpose

Diabetic retinopathy (DR) is associated with retinal neuronal and vascular damage. DR has previously been shown to affect the photosensitive retinal ganglion cells (pRGCs). PRGCs are essential for the entrainment of circadian rhythms; thus, DR progression could lead to worsening sleep quality and mood. We investigate the relationship between increasing DR severity, and its impact on sleep quality and mood.

Methods

A total of 430 participants with DR, and 303 healthy controls with no ocular disease or preexisting sleep disorders were recruited. DR severity was grouped as follows: 1, mild nonproliferative (NPDR); 2, moderate/severe NPDR; and 3, proliferative diabetic retinopathy (PDR). Sleep, mood, and quality of life were assessed using the Pittsburgh Sleep Quality Index (PSQI), quality of life (SF-36), and Hospital Anxiety and Depression Score (HADS) questionnaires. Data were analyzed by severity of DR, and correlated with sleep, QOL, and mood and compared to controls.

Results

No significant difference between PSQI scores in the DR group or the control group was identified despite severity of DR. Mean anxiety and depression scores were within the normal range for both groups. Despite a lower general health and physical function, the DR group had lower anxiety scores than controls.

Conclusions

These data show that even in severe DR, sleep quality is similar to controls. However, this could be explained by the majority of individuals in this study having good visual acuities in the better eye with a residual population of pRGCs remaining unaffected by DR.

Therapeutic effect of lutein supplement on non-proliferative diabetic retinopathy: A retrospective study

This study retrospectively evaluated the effect of lutein supplement (LS) on patients with non-proliferative diabetic retinopathy (NPDR).A total of 72 patients with NPDR were included in this study. All patients received Zeaxanthin during the study period. In addition, 36 patients also received LS and were assigned to the treatment group, while the other 36 patients did not receive LS and were assigned to the control group. All patients were treated for a total of 4 months. The endpoints included visual acuity (VA), contrast sensitivity (CS), and glare sensitivity (GS). In addition, any adverse events were also assessed. All endpoints were measured before and after 4-month treatment.Before treatment, there were no significant differences in VA (P = .75), CS (P = .71), and GS (P = .73) between two groups. After 4-month treatment, there were still no significant differences in all endpoints of VA (P = .66), CS (P = .58), and GS (P = .61) between two groups. No adverse events were recorded in either group.The results of this retrospective study showed that LS may not benefit for patients with NPDR after 4-month treatment. More high quality randomized controlled trials should still be needed to warrant the results of this study.

Diabetic retinopathy in Ethiopia: A systematic review and meta-analysis

AIMS

this systemic review and meta-analysis was aimed at determining the level of diabetic retinopathy among diabetes mellitus patients in Ethiopia.

MATERIALS AND METHODS

PubMed, Science Direct, Google Scholar and Excerpta Medica Database (EMBASE) were searched. The data were extracted using Microsoft Excel and analyzed by using STATA version 11. Publication bias was checked by funnel plot and more objectively through Egger's regression test, with P < 0.05 considered to indicate potential publication bias. Heterogeneity of studies was checked using the I² test. Pooled analysis was conducted. Subgroup analysis was done by region. Sensitivity analysis was employed to see the effect of single study on the overall estimation. STATA version 11 statistical software was used for meta-analysis.

RESULTS

The overall prevalence of retinopathy was 19.48% (95% CI: 15.95, 23.01) Based on the subgroup analysis the prevalence of retinopathy was 12.48% in SNNPR, 24.8% in Oromia, 19.99% in Amhara, and 16.29% in Addis Ababa.

CONCLUSION

The prevalence of diabetic retinopathy among Diabetes mellitus patients is high. Therefore, close monitoring of the patient prognosis and appropriate prevention techniques is essential.

Efficacy of fenofibrate for diabetic retinopathy: A systematic review protocol

BACKGROUND

Numerous studies have reported the efficacy of fenofibrate for patients with diabetic retinopathy (DRP). No systematic review has, however, addressed its efficacy for DRP. Thus, this systematic review will firstly evaluate the efficacy and safety of fenofibrate for patients with DRP.

METHODS

This study will search the following databases: PUMBED, EMBASE, CINAHI, ACMD, CENTRAL, CBM, CNKI, VIP, and WANGFANG, along with grey literature from inception to the present. We will accept randomized controlled trials on evaluating the efficacy and safety of fenofibrate for DRP. The primary outcome is the progression of DRP. The secondary outcomes are vision loss, development of diabetic macular edema, aggravation of hard exudates, quality of life, and any adverse events. Methodological quality of each included study will be assessed by using Cochrane Collaboration risk of bias tool. In addition, Grading of Recommendations Assessment, Development and Evaluation tool will also be used to evaluate the overall strength of the evidence. Two independent reviewers will conduct all procedures of study selection, data extraction, and methodological assessment. Any disagreements will be consulted with a third reviewer. RevMan 5.3 software will be used to pool data and to carry out the meta-analysis if it is possible.

RESULTS

In present study, we anticipate to find a considerable number of published studies presenting evidence on efficacy and safety of fenofibrate for DRP.

CONCLUSION

The findings of this systematic review will provide latest evidence of fenofibrate for patients with DRP.

DISSEMINATION AND ETHICS

The findings of this scoping review will be disseminated in print, conferences, or by peer-reviewed journals. No ethical approval is needed for this systematic review, because it is a literature-based study.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42019121869.

[Screening for diabetic retinopathy by non-mydriatic fundus photography: First national campaign in Lebanon]

INTRODUCTION

Diabetic retinopathy (DR) is a leading cause of blindness worldwide. Non-mydriatic fundus photography (NMFP) has been adopted as a screening tool for this disease. We aim to determine the prevalence of DR through this method in Lebanese diabetic patients and to evaluate the impact of such screening in this population.

MATERIALS AND METHODS

This study explores data from an awareness and screening campaign conducted in Lebanon. Diabetic patients from multiple regions were referred by their endocrinologists to undergo NMFP using the Optomed SmartScope^® handheld fundus camera. Photographs were interpreted by a remote observer, and recommendations were given accordingly. The prevalence of DR was calculated, and statistical analyses were performed on the clinical characteristics, fundus findings and number of referrals to ophthalmologists.

RESULTS

The campaign lasted 11 months, during which 2205 patients were examined in 37 screening locations. Out of the 97.41% of patients with type 2 diabetes mellitus, 12.56% had signs of DR, with no significant difference between the regions. 6.28% of the photos were uninterpretable. Positive results were associated with a longer duration of diabetes (P<0.01), treatment with insulin (P<0.01), as well as the presence and chronicity of systemic hypertension (P=0.01). 25% of patients with positive testing were retrospectively asked about their follow-up; only one third had an ophthalmologic examination as per the recommendation, among whom 68.18% underwent treatment for proliferative DR and/or diabetic macular edema.

CONCLUSION

Tele-ophthalmology is useful in mass screening for DR. The importance of dilated fundus examinations still needs to be highlighted for diabetic patients, and better collaboration between endocrinologists and ophthalmologists is required to improve screening outcomes.

Chrysin Ameliorates Malfunction of Retinoid Visual Cycle through Blocking Activation of AGE-RAGE-ER Stress in Glucose-Stimulated Retinal Pigment Epithelial Cells and Diabetic Eyes

Diabetes-associated visual cycle impairment has been implicated in diabetic retinopathy, and chronic hyperglycemia causes detrimental effects on visual function. Chrysin, a naturally occurring flavonoid found in various herbs, has anti-inflammatory, antioxidant, and neuroprotective properties. The goal of the current study was to identify the retinoprotective role of chrysin in maintaining robust retinoid visual cycle-related components. The in vitro study employed human retinal pigment epithelial (RPE) cells exposed to 33 mM of glucose or advanced glycation end products (AGEs) in the presence of 1–20 μM chrysin for three days. In the in vivo study, 10 mg/kg of chrysin was orally administrated to db/db mice. Treating chrysin reversed the glucose-induced production of vascular endothelial growth factor, insulin-like growth factor-1, and pigment epithelium-derived factor (PEDF) in RPE cells. The outer nuclear layer thickness of chrysin-exposed retina was enhanced. The oral gavage of chrysin augmented the levels of the visual cycle enzymes of RPE65, lecithin retinol acyltransferase (LRAT), retinol dehydrogenase 5 (RDH5), and rhodopsin diminished in db/db mouse retina. The diabetic tissue levels of the retinoid binding proteins and the receptor of the cellular retinol-binding protein, cellular retinaldehyde-binding protein-1, interphotoreceptor retinoid-binding protein and stimulated by retinoic acid 6 were restored to those of normal mouse retina. The presence of chrysin demoted AGE secretion and AGE receptor (RAGE) induction in glucose-exposed RPE cells and diabetic eyes. Chrysin inhibited the reduction of PEDF, RPE 65, LRAT, and RDH5 in 100 μg/mL of AGE-bovine serum albumin-exposed RPE cells. The treatment of RPE cells with chrysin reduced the activation of endoplasmic reticulum (ER) stress. Chrysin inhibited the impairment of the retinoid visual cycle through blocking ER stress via the AGE-RAGE activation in glucose-stimulated RPE cells and diabetic eyes. This is the first study demonstrating the protective effects of chrysin on the diabetes-associated malfunctioned visual cycle.

Clinical and experimental study on angiopoietin-like protein 8 associated with proliferative diabetic retinopathy

AIM

To confirm the role of angiopoietin-like protein 8 (Angptl 8) in proliferative diabetic retinopathy (PDR).

METHODS

The sera and aqueous humor of 10 PDR patients and 10 non-diabetic retinopathy (NDR) patients (idiopathic macular hole patients) were collected and the expression of Angptl 8 was detected by enzyme linked immune-sorbent assay (ELISA). Experimental diabetes mice model was induced with streptozotocin. The expression of glycosylated hemoglobin and Angptl 8 in sera was detected. Recombinant Angptl 8 was re-infused into wild type (WT) diabetic mice and spatial frequency threshold and contrast sensitivity were measured. In vitro retinal pigment epithelium (RPE) were stimulated by recombinant Angptl 8 for 24h. MMT assay were used to detect cell proliferation. At the same time, qRT-PCR and Western blot was used to measure the expression of proliferation-related factors in PRE cells.

RESULTS

The expression of Angptl 8 was markedly increased in the sera and aqueous humor of PDR patients (F=99.02, P<0.0001 in sera; t=10.42, P<0.0001 in aqueous). After successfully establishing the diabetic mice model, we found that glycosylated hemoglobin and Angptl 8 expression levels were increased. Re-infusion of recombinant Angptl 8 into WT diabetic mice could further decrease spatial frequency threshold and contrast sensitivity (P<0.01). In vitro, RPE cells stimulated by recombinant Angptl 8 could increase the relative absorbance of MMT assay (1.486±0.042 vs 1.000±0.104, P<0.05) and proliferating cell nuclear antigen (PCNA) expression (0.55±0.01 vs 0.29±0.03, P<0.05). The proliferative effect of Angptl 8 is mainly mediated by increasing the expression of proliferation-activating factors cyclin A1 (4.973±0.205 vs 2.720±0.197, P<0.05), cyclin F (5.690±0.219 vs 4.297±0.292, P<0.05) and E2F2 (2.297±0.102 vs 1.750±0.146, P<0.05), and reducing the expression of proliferation-inhibiting factors cdkn1 (2.370±0.074 vs 3.317±0.135, P<0.05) and cdkn2 (4.793±0.065 vs 5.387±0.149, P<0.05).

CONCLUSION

The expression of Angptl 8 is increased in PDR, and the increased Angptl 8 can promote proliferation and increase proliferation-related factors.