IDF Diabetes Atlas: A review of studies utilising retinal photography on the global prevalence of diabetes related retinopathy between 2015 and 2018

Diabetes and the associated complications: The role of antioxidants in diabetes therapy and care

Diabetes mellitus (DM) is a chronic metabolic disorder characterized by high blood sugar levels (hyperglycemia). Poorly managed diabetes can lead to complications affecting multiple organ systems. Antioxidants play a crucial role in reducing oxidative stress caused by reactive oxygen species (ROS), primarily triggered by uncontrolled high blood sugar levels in diabetes. Antioxidants like vitamin C, E, selenium, and alpha-lipoic acid, when used as supplements, have shown promise in reducing oxidative stress markers and improving antioxidant status in laboratory and animal studies and diabetic patients. Antioxidant supplementation may help reduce the risk of diabetic complications such as neuropathy, nephropathy, retinopathy, and cardiovascular disease. Additionally, antioxidants also have anti-inflammatory properties, which could be beneficial in reducing inflammation associated with diabetes. Antioxidant supplementation has been shown to enhance endothelial function, insulin sensitivity, and glucose metabolism, thereby aiding in glycemic control and overall diabetic management. Combining antioxidants with certain medications may have therapeutic benefits, such as effectively neutralizing free radicals and enhancing the regulation of antioxidant defense systems. This review presents an update on diabetes, the sources of free radical generation, the body's natural defense mechanisms, the clinical evidence regarding using antioxidants in managing diabetic complications, and the potential new therapeutic approaches. Overall, antioxidant supplementation may offer some benefits in managing diabetic complications. However, further studies are needed to understand the mechanisms of action, determine the optimal supplementation, explore potential interactions with other medications, and conduct long-term studies to establish the possible use of antioxidants for optimal benefits in diabetes care.

Müller Cells Harboring Exosomal lncRNA OGRU Modulate Microglia Polarization in Diabetic Retinopathy by Serving as miRNA Sponges

Diabetic retinopathy (DR) is one of the most common complications of diabetes worldwide and is associated with visual loss and blindness. However, effective treatments for both early- and late-stage DR remain lacking. A streptozotocin-induced diabetic mouse model and high glucose (HG)-treated Müller cell model were established. M1/M2 microglia polarization was assessed by immunofluorescence staining and flow cytometry. Expression of long noncoding RNA (lncRNA) OGRU, cytokines, and other key molecules was detected by quantitative RT-PCR or Western blot. ELISA was used to monitor cytokine secretion. Müller cell-derived exosomes were isolated and characterized by nanopartical tracking analysis, Western blot, and transmission electron microscopy, and exosome uptake assay was used to monitor the intercellular transport of exosomes. Associations among lncRNA-miRNA-mRNA networks were validated by RNA pulldown and RNA immunoprecipitation and dual luciferase assays. Increased M1 polarization but decreased M2 polarization of retinal microglia was observed in DR mice. HG-treated Müller cell-derived exosomes transported OGRU into microglia and promoted microglia polarization toward the M1 phenotype. Mechanistically, OGRU served as a competing endogenous RNA for miR-320-3p, miR-221-3p, and miR-574-5p to regulate aldose reductase (AR), PFKFB3, and glucose transporter 1 (GLUT1) expression in microglia, respectively. Loss of miR-320-3p/miR-221-3p/miR-574-5p or reinforced AR/PFKFB3/GLUT1 abrogated OGRU silencing-mediated microglia polarization in vitro. In vivo studies further showed that OGRU/miR-320-3p/AR, OGRU/miR-221-3p/PFKFB3, and OGRU/miR-574-5p/GLUT1 axes regulated microglia polarization in DR mice. Collectively, Müller cell-derived exosomal OGRU regulated microglia polarization in DR by modulating OGRU/miR-320-3p/AR, OGRU/miR-221-3p/PFKFB3, and OGRU/miR-574-5p/GLUT1 axes.

ARTICLE HIGHLIGHTS

New insights on genetic background of major diabetic vascular complications

BACKGROUND

By 2045, it is expected that 693 million individuals worldwide will have diabetes and with greater risk of morbidity, mortality, loss of vision, renal failure, and a decreased quality of life due to the devastating effects of macro- and microvascular complications. As such, clinical variables and glycemic control alone cannot predict the onset of vascular problems. An increasing body of research points to the importance of genetic predisposition in the onset of both diabetes and diabetic vascular complications.

OBJECTIVES

Purpose of this article is to review these approaches and narrow down genetic findings for Diabetic Mellitus and its consequences, highlighting the gaps in the literature necessary to further genomic discovery.

MATERIAL AND METHODS

In the past, studies looking for genetic risk factors for diabetes complications relied on methods such as candidate gene studies, which were rife with false positives, and underpowered genome-wide association studies, which were constrained by small sample sizes.

RESULTS

The number of genetic findings for diabetes and diabetic complications has over doubled due to the discovery of novel genomics data, including bioinformatics and the aggregation of global cohort studies. Using genetic analysis to determine whether diabetes individuals are at the most risk for developing diabetic vascular complications (DVC) might lead to the development of more accurate early diagnostic biomarkers and the customization of care plans.

CONCLUSIONS

A newer method that uses extensive evaluation of single nucleotide polymorphisms (SNP) in big datasets is Genome-Wide Association Studies (GWAS).

Demographic and Systemic Risk Factors for Persistent Corneal Edema Following Cataract Surgery in Patients With and Without Diabetes

PURPOSE

To identify risk factors associated with the development of corneal edema (CE) and the need for corneal transplantation following cataract surgery.

DESIGN

Retrospective cohort study.

METHODS SETTING

Nation-wide sample of Medicare beneficiaries from 2011-2015.

STUDY POPULATION

Medicare beneficiaries aged over 65 years who received cataract surgery between 2011-2014 with at least 1 year of continuous follow-up. Data was retrieved from the Denominator and Physician Supplier Part B file from the Center for Medicare and Medicaid Services.

MAIN OUTCOME(S) AND MEASURE(S)

The main outcome was the association between demographic characteristics (e.g., age, sex, race/ethnicity) and systemic factors including diabetes status, hypertension, and tobacco use on the incidence of CE and the subsequent need for corneal transplantation following cataract surgery.

RESULTS

Among 187,746 beneficiaries, 67,734 had diabetes and 120,012 did not. Beneficiaries with diabetes were more likely to develop CE compared to those without (Odds ratio [OR] 1.19, 95% Confidence Interval [CI] [1.02-1.40]). Compared to those aged 65-74, beneficiaries aged 75-84 and over 85 were more likely to develop CE (OR 1.29 [1.09-1.52]) and OR 1.96 [1.55-2.46], respectively). Asian (OR 2.42 [1.66-3.40]), Hispanic (OR 2.60 [1.73-3.74]), and North American Native (OR 3.59 [1.78-6.39]) race was associated with increased likelihood of developing CE. North American Native beneficiaries had higher risk of requiring corneal transplantation compared to White beneficiaries (OR 9.30 [2.26-25.31]). Female sex decreased likelihood of requiring corneal transplantation post-operatively (OR 0.56 [0.36-0.87]). Amongst those with diabetes, the presence of proliferative diabetic retinopathy increased the likelihood of developing CE (OR 1.94 [1.05-3.39]).

CONCLUSION

Older age, diabetes, and non-White race elevate the risk of CE following cataract surgery, with race incurring the highest risk. Further research is needed to understand the factors underlying the significantly increased risk of CE in racial and ethnic minorities within the United States.

Prior-guided attention fusion transformer for multi-lesion segmentation of diabetic retinopathy

To solve the issue of diagnosis accuracy of diabetic retinopathy (DR) and reduce the workload of ophthalmologists, in this paper we propose a prior-guided attention fusion Transformer for multi-lesion segmentation of DR. An attention fusion module is proposed to improve the key generator to integrate self-attention and cross-attention and reduce the introduction of noise. The self-attention focuses on lesions themselves, capturing the correlation of lesions at a global scale, while the cross-attention, using pre-trained vessel masks as prior knowledge, utilizes the correlation between lesions and vessels to reduce the ambiguity of lesion detection caused by complex fundus structures. A shift block is introduced to expand association areas between lesions and vessels further and to enhance the sensitivity of the model to small-scale structures. To dynamically adjust the model's perception of features at different scales, we propose the scale-adaptive attention to adaptively learn fusion weights of feature maps at different scales in the decoder, capturing features and details more effectively. The experimental results on two public datasets (DDR and IDRiD) demonstrate that our model outperforms other state-of-the-art models for multi-lesion segmentation.

Implementation of Artificial Intelligence-Based Diabetic Retinopathy Screening in a Tertiary Care Hospital in Quebec: Prospective Validation Study

BACKGROUND

Diabetic retinopathy (DR) affects about 25% of people with diabetes in Canada. Early detection of DR is essential for preventing vision loss.

OBJECTIVE

We evaluated the real-world performance of an artificial intelligence (AI) system that analyzes fundus images for DR screening in a Quebec tertiary care center.

METHODS

We prospectively recruited adult patients with diabetes at the Centre hospitalier de l'Université de Montréal (CHUM) in Montreal, Quebec, Canada. Patients underwent dual-pathway screening: first by the Computer Assisted Retinal Analysis (CARA) AI system (index test), then by standard ophthalmological examination (reference standard). We measured the AI system's sensitivity and specificity for detecting referable disease at the patient level, along with its performance for detecting any retinopathy and diabetic macular edema (DME) at the eye level, and potential cost savings.

RESULTS

This study included 115 patients. CARA demonstrated a sensitivity of 87.5% (95% CI 71.9-95.0) and specificity of 66.2% (95% CI 54.3-76.3) for detecting referable disease at the patient level. For any retinopathy detection at the eye level, CARA showed 88.2% sensitivity (95% CI 76.6-94.5) and 71.4% specificity (95% CI 63.7-78.1). For DME detection, CARA had 100% sensitivity (95% CI 64.6-100) and 81.9% specificity (95% CI 75.6-86.8). Potential yearly savings from implementing CARA at the CHUM were estimated at CAD $245,635 (US $177,643.23, as of July 26, 2024) considering 5000 patients with diabetes.

CONCLUSIONS

Our study indicates that integrating a semiautomated AI system for DR screening demonstrates high sensitivity for detecting referable disease in a real-world setting. This system has the potential to improve screening efficiency and reduce costs at the CHUM, but more work is needed to validate it.

The incidence and prevalence of diabetic macular edema and proliferative diabetic retinopathy, their progression to visual impairment and patterns in their intravitreal treatment in the Finnish population

PURPOSE

The worldwide prevalence of diabetes mellitus (DM) continues to increase. As DM is linked to various ophthalmological comorbidities, it is crucial to understand the incidence and the treatment patterns of these complications to minimise the treatment burden for the patient and the healthcare system. This study aims to evaluate the incidence and prevalence of diabetic macular oedema (DME) and proliferative diabetic retinopathy (PDR) and to analyse intravitreal (IVT) treatment patterns and responses in the Finnish population with diabetes.

METHODS

A nationwide data register containing details of over 20-year-old individuals with diabetes was used in the analyses.

RESULTS

The incidence and prevalence of DME and PDR among the Finnish population with diabetes either declined or remained stable during 2007-2017 (Incidence rate: DME -40.8%, PDR -65.3%; prevalence rate: DME +4.7%, PDR -11.2%). During the same period, number of persons suffering from diabetes increased by +58.3%. The total number of IVT injections increased by 261.7%; the number of patients receiving IVT treatments increased by 133.6% from 2011 to 2017, reflecting changes in patient numbers in the ophthalmology departments. Furthermore, irrespective of the rising number of patients with diabetes, the numbers with visual impairment declined by 75.8% among DME and by 75.7% among PDR patients in 2007-2017.

CONCLUSIONS

Regardless of the considerable increase in the workload of ophthalmology departments, the healthcare system has been able to reduce both the age and sex standardised incidence of DME and PDR among the diabetic population suffering from a visual impairment associated with this disease.

Referrals for proliferative diabetic retinopathy from two UK diabetic retinopathy screening services: a 10-year analysis of visual outcomes, requirement for vitrectomy, and mortality

BACKGROUND/OBJECTIVES

To determine long-term outcomes of patients referred with proliferative diabetic retinopathy (PDR) from diabetic eye screening programmes (DESP) to tertiary care centres in the United Kingdom (UK).

METHODS

Retrospective multicentre study of patients referred from two DESPs in the UK over a 36-month period (2007-9) and followed-up for 10 years. Critical outcomes included severe vision loss (SVL) and the need for vitrectomy. Other outcomes assessed included moderate vision loss (MVL), and patient survival time. Univariate and multiple variable Cox proportional hazards regressions were used to analyse survival outcomes.

RESULTS

212 eyes of 150 patients were referred with a diagnosis of PDR. 109 eyes of 72 patients were confirmed to have active PDR and included in the study. 61% of patients had low-risk PDR, while 39% exhibited high-risk features in at least one eye. Eight (7.3%) eyes developed SVL and 16 (14.7%) MVL during follow up. Vitrectomy was required in 24% (95% CI: 15 to 31%) of all PDR eyes and was most commonly performed for vitreous haemorrhage (65%). The 10-year survival in all PDR patients was 76% (95% CI: 63 to 85%) with the mean time to death for all deceased patients being 5.4 ± 3.6 years. On multivariable analysis, only age was found to have a significant association with the survival of patients with PDR.

CONCLUSIONS

During the 10 year follow up SVL was uncommon, but MVL occurred in almost one-fifth of the eyes. Approximately 1 in 4 eyes required vitrectomy, highlighting its significance in patient management.

Management of Microcomplications of Diabetes Mellitus: Challenges, Current Trends, and Future Perspectives in Treatment

Diabetes mellitus is a chronic metabolic disorder characterized by high blood sugar levels, which can lead to severe health issues if not managed effectively. Recent statistics indicate a significant global impact, with 463 million adults diagnosed worldwide and this projected to rise to 700 million by 2045. Type 1 diabetes is an autoimmune disorder where the immune system attacks pancreatic beta cells, reducing insulin production. Type 2 diabetes is primarily due to insulin resistance. Both types of diabetes are linked to severe microvascular and macrovascular complications if unmanaged. Microvascular complications, such as diabetic retinopathy, nephropathy, and neuropathy, result from damage to small blood vessels and can lead to organ and tissue dysfunction. Chronic hyperglycemia plays a central role in the onset of these complications, with prolonged high blood sugar levels causing extensive vascular damage. The emerging treatments and current research focus on various aspects, from insulin resistance to the intricate cellular damage induced by glucose toxicity. Understanding and intervening in these pathways are critical for developing effective treatments and managing diabetes long term. Furthermore, ongoing health initiatives, such as increasing awareness, encouraging early detection, and improving treatments, are in place to manage diabetes globally and mitigate its impact on health and society. These initiatives are a testament to the collective effort to combat this global health challenge.

Evaluation of an AI algorithm trained on an ethnically diverse dataset to screen a previously unseen population for diabetic retinopathy

PURPOSE

This study aimed to determine the generalizability of an artificial intelligence (AI) algorithm trained on an ethnically diverse dataset to screen for referable diabetic retinopathy (RDR) in the Armenian population unseen during AI development.

METHODS

This study comprised 550 patients with diabetes mellitus visiting the polyclinics of Armenia over 10 months requiring diabetic retinopathy (DR) screening. The Medios AI-DR algorithm was developed using a robust, diverse, ethnically balanced dataset with no inherent bias and deployed offline on a smartphone-based fundus camera. The algorithm here analyzed the retinal images captured using the target device for the presence of RDR (i.e., moderate non-proliferative diabetic retinopathy (NPDR) and/or clinically significant diabetic macular edema (CSDME) or more severe disease) and sight-threatening DR (STDR, i.e., severe NPDR and/or CSDME or more severe disease). The results compared the AI output to a consensus or majority image grading of three expert graders according to the International Clinical Diabetic Retinopathy severity scale.

RESULTS

On 478 subjects included in the analysis, the algorithm achieved a high classification sensitivity of 95.30% (95% CI: 91.9%-98.7%) and a specificity of 83.89% (95% CI: 79.9%-87.9%) for the detection of RDR. The sensitivity for STDR detection was 100%.

CONCLUSION

The study proved that Medios AI-DR algorithm yields good accuracy in screening for RDR in the Armenian population. In our literature search, this is the only smartphone-based, offline AI model validated in different populations.

Association of Anemia and Diabetic Retinopathy Among Patients With Type 2 Diabetes Mellitus: Retrospective Cross-Sectional Study

Introduction Type 2 diabetes mellitus (T2DM) is a common metabolic disorder characterized by the combination of defective insulin secretion and the inability of insulin-sensitive tissues to respond appropriately to insulin. Diabetic retinopathy (DR) is a common microvascular complication that can result in a preventable cause of blindness. Research to determine the prevalence of anemia among diabetic patients is necessary to assess whether treatment practices should be changed. Anemia is a common complication in patients with T2DM and has been associated with the progression of DR. In this study, our aim is to determine the prevalence of DR and its association with hemoglobin levels in patients diagnosed with T2DM in Dubai, UAE. Methods In this retrospective cross-sectional study, we extracted the data using electronic medical records. The study was performed over a span of three years in Dubai from 2019 to 2022. A total of 368 T2DM patients were included based on retinal exam findings classified into mild, moderate, severe non-proliferative retinopathy, and proliferative retinopathy. Descriptive statistics were used for categorical (frequency, percentage) and continuous variables (mean, SD), with chi-square/Fisher exact tests for categorical associations, ANOVA for continuous variables, and multiple logistic regression to identify DR risk factors, using OR, 95% CI, and p < 0.05 for significance. Results The prevalence of anemia (defined as hemoglobin levels ≤13 mg/dL for men and ≤12 mg/dL for women) was observed in 39.4% of individuals with DR aged between 40 and 88 years; 60.6% of the patients had normal hemoglobin, while 91 individuals (24.7%) exhibited mild anemia, 53 individuals (14.4%) showed moderate anemia, and only one individual (0.3%) had severe anemia. DR grading was as follows: mild non-proliferative DR (16.8%), moderate non-proliferative DR (30.2%), severe non-proliferative DR (13.3%), and proliferative DR (39.7%). Macular edema was present in 59.2% of patients, showing a statistically significant association with more severe DR stages (p < 0.0001). No significant association was found between hemoglobin levels and DR severity (p = 0.568). However, among males, a significant difference in mean hemoglobin levels across DR grades was observed (p = 0.009), with higher hemoglobin levels associated with lower odds of severe DR (OR = 0.775, p = 0.036). Macular edema strongly predicted DR severity, with significant odds ratios across all stages (p < 0.0001). Conclusions There is a significant prevalence of anemia among the examined population. DR severity was notably associated with lower hemoglobin levels in males, and macular edema was significantly linked to more severe stages of DR. Vigilant monitoring and integrated care for both anemia and DR are crucial to optimize patient outcomes and mitigate complications. Regular retinopathy screening is essential for early detection and timely intervention, particularly considering the challenges posed by anemia, such as delayed wound healing and increased infection risk post-screening.

Association of SDF-1-3' Gene A Variant with Diabetic Retinopathy in the Hungarian Population

We investigated the association between the SDF-1-3' (c801G > A) variant and the development of diabetic macular edema (DME) or proliferative diabetic retinopathy (PDR) in a Hungarian cohort. SDF-1-3' (c801G > A) was genotyped in 103 patients with diabetic retinopathy and 31 age- and sex-matched non-diabetic controls. Central retinal and choroidal thickness was measured by swept-source optical coherence tomography. The distribution of heterozygous and homozygous SDF-1-3' (c801G > A) genotypes was similar in diabetic and control subjects. The SDF-3'(c801AA) genotype was associated with DME (n = 94 eyes, allele distribution p = 0.006, genotype distribution p = 0.01 OR: 2.48, 95% CL: 1.21-5.08) in both univariable and multivariable modelling, independent of duration and type of diabetes, HbA1C, hypertension and microalbuminuria (p = 0.03). DME occurred earlier in patients carrying the SDF-1 (c801A) allele (Kaplan-Meier analysis, log-rank test p = 0.02). A marginally significant association was found between the presence of the SDF-1 (c801A) allele and the development of PDR (n = 89 eyes, p = 0.06). The SDF-1-3' (c801A) allele also showed a correlation with central retinal (p = 0.006) and choroidal (p = 0.08) thickness. SDF-1-3' (c801G > A) is involved in the development of macular complications in DM independent of critical clinical factors, suggesting that SDF-1 may be a future therapeutic target for high-risk patients, especially those carrying the SDF-1 (c801A) allele.

Comparing the efficacy of dexamethasone implant and anti-VEGF for the treatment of macular edema: A systematic review and meta-analysis

OBJECTIVES

To evaluate the clinical efficacy of dexamethasone (DEX) implant, for the treatment of macular edema (ME) caused by retinal vein occlusion (RVO) and diabetic retinopathy (DR) through a systematic review and meta-analysis.

METHODS

The PubMed, Embase and Cochrane Library databases were comprehensively searched from inception to November 21, 2022, for studies evaluating the clinical efficacy of DEX implant for patients with retinal vein occlusion macular edema (RVO-ME) or diabetic macular edema (DME). Randomized controlled trials (RCTs) published in English were considered eligible. The Cochrane Collaboration tool was applied to assess the risk of bias in each study. Effect estimates with 95% confidence intervals (CIs) were pooled using the random effects model. We also conducted subgroup analyses to explore the sources of heterogeneity and the stability of the results.

RESULTS

This meta-analysis included 8 RCTs (RVO-ME [n = 2] and DME [n = 6]) assessing a total of 336 eyes. Compared with anti-VEGF therapy, DEX implant treatment achieved superior outcomes in terms of best corrected visual acuity (BCVA) (mean difference [MD] = -3.68 ([95% CI, -6.11 to -1.25], P = 0.003), and no heterogeneity was observed (P = 0.43, I2 = 0%). DEX implant treatment also significantly reduced central macular thickness (CMT) compared with anti-VEGF treatment (MD = -31.32 [95% CI, -57.92 to -4.72], P = 0.02), and there was a high level of heterogeneity between trials (P = 0.04, I2 = 54%). In terms of severe adverse events, DEX implant treatment had a higher risk of elevated intraocular pressure than anti-VEGF therapy (RR = 6.98; 95% CI: 2.16 to 22.50; P = 0.001), and there was no significant difference in cataract progression between the two groups (RR = 1.83; 95% CI: 0.63 to 5.27, P = 0.31).

CONCLUSIONS

Compared with anti-VEGF therapy, DEX implant treatment is more effective in improving BCVA and reducing ME. Additionally, DEX implant treatment has a higher risk of elevated intraocular pressure. Due to the small number of studies and the short follow-up period, the results should be interpreted with caution. The long-term effects of the two treatments need to be further determined.

TRIAL REGISTRATION

Prospero Registration Number CRD42021243185.

Fasting pancreatic polypeptide predicts incident microvascular and macrovascular complications of type 2 diabetes: An observational study

AIMS

Pancreatic polypeptide (PP) is elevated in people with vascular risk factors such as type 2 diabetes or increased visceral fat. We investigated potential relationships between PP and microvascular and macrovascular complications of diabetes.

MATERIALS AND METHODS

Animal study: Subcutaneous PP infusion for 4 weeks in high fat diet mouse model. Retinal mRNA submitted for Ingenuity Pathway Analysis. Human study: fasting PP measured in 1478 participants and vascular complications recorded over median 5.5 (IQR 4.9-5.8) years follow-up.

RESULTS

Animal study: The retinal transcriptional response to PP was indicative of cellular stress and damage, and this footprint matched responses described in previously published studies of retinal disease. Of mechanistic importance the transcriptional landscape was consistent with upregulation of folliculin, a recently identified susceptibility gene for diabetic retinopathy. Human study: Adjusting for established risk factors, PP was associated with prevalent and incident clinically significant retinopathy (odds ratio (OR) 1.289 (1.107-1.501) p = 0.001; hazard ratio (HR) 1.259 (1.035-1.531) p = 0.0213), albuminuria (OR 1.277 (1.124-1.454), p = 0.0002; HR 1.608 (1.208-2.141) p = 0.0011), and macrovascular disease (OR 1.021 (1.006-1.037) p = 0.0068; HR 1.324 (1.089-1.61), p = 0.0049), in individuals with type 2 diabetes, and progression to diabetes in non-diabetic individuals (HR 1.402 (1.081-1.818), p = 0.0109).

CONCLUSIONS

Elevated fasting PP is independently associated with vascular complications of diabetes and affects retinal pathways potentially influencing retinal neuronal survival. Our results suggest possible new roles for PP-fold peptides in the pathophysiology of diabetes complications and vascular risk stratification.

Effect of a self-care promoting program on engagement in self-care behaviors and health-related outcomes among persons with type 2 diabetes and diabetic retinopathy: A single-blind randomized controlled trial

Background

Diabetic retinopathy (DR) is the most common microvascular complication of diabetes, leading to visual impairment and eventual blindness. Promoting self-care behaviors is crucial in controlling DR progression and preventing blindness.

Objective

This study aimed to investigate the effects of a Self-Care Promoting Program (SCPP) on engagement in self-care behaviors, HbA1c levels, visual acuity (VA), severity of DR, and vision-related quality of life (VRQoL) among individuals with type 2 diabetes and DR.

Methods

This study employed a single-blind randomized controlled trial design to compare SCPP with conventional diabetic care interventions (standard care). The SCPP was based on the Self-Care of Chronic Illness Theory, Self-efficacy theory, and the Association of Diabetic Care and Education Specialist (ADCES) guidelines incorporating health education, self-care maintenance, monitoring, and management skills training over 12 weeks. Ninety-eight participants were randomly allocated to the experimental or control group (n = 49 per group). While the experimental group received SCPP alongside standard care, the control group received standard care alone. Data collection occurred between May 2022 and March 2023 and included demographic information, the Self-Care of Diabetes Index questionnaire (SCODI), the self-care for diabetes eye care questionnaire (SCFDE), the impact of visual impairment questionnaire (IVI-Thai version), and retinal images for DR severity grading. Data analysis utilized descriptive statistics, Chi-Square tests, t-tests, and MANOVA.

Results

Following 8 and 16 weeks of SCPP, the experimental group had significantly higher mean scores in engagement with self-care and eye-care behaviors compared to the control group (p <0.001). The highest scores were observed in self-care and eye-care confidence behaviors, followed by maintenance, monitoring, and management. Furthermore, HbA1c levels and VRQoL significantly decreased and were lower than those of the control group at week 16 (p <0.001 and p <0.05, respectively). However, there were no significant differences in VA, and DR severity increased in both groups by week 16.

Conclusion

SCPP benefits individuals with DR, enhancing their confidence and ability to perform, monitor, and manage self-care behaviors. These strategies contribute to improved diabetes management, enhanced quality of life, and reduced DR-related blindness. Integrating SCPP into routine DR management is recommended, with nurses playing a pivotal role in overseeing and driving this integration, highlighting the critical role of nurses in managing this widespread global disease.

Trial Registry Number

Thai Clinical Trials Registration (TCTR20230302002).

Nuclear proteins and diabetic retinopathy: a review

Diabetic retinopathy (DR) is an eye disease that causes blindness and vision loss in diabetic. Risk factors for DR include high blood glucose levels and some environmental factors. The pathogenesis is based on inflammation caused by interferon and other nuclear proteins. This review article provides an overview of DR and discusses the role of nuclear proteins in the pathogenesis of the disease. Some core proteins such as MAPK, transcription co-factors, transcription co-activators, and others are part of this review. In addition, some current advanced treatment resulting from the role of nuclear proteins will be analyzes, including epigenetic modifications, the use of methylation, acetylation, and histone modifications. Stem cell technology and the use of nanobiotechnology are proposed as promising approaches for a more effective treatment of DR.

Incidence of diabetic retinopathy in anti-tnf treated rheumatic disease patients with type 2 diabetes

OBJECTIVE

This study aimed to evaluate the impact of anti-TNF (biological) therapies on the incidence and progression of diabetic retinopathy.

MATERIALS AND METHODS

A cross-sectional analysis of 50 diabetic patients with rheumatic diseases (group 1) was performed. An age-, sex-, and HbA1c-matched control group (group 2) was formed from a pool of diabetic patients who underwent regular eye examinations. The presence or absence of diabetic retinopathy was also assessed. Comorbidities such as hypertension, coronary artery disease, and hyperlipidemia were also evaluated as possible confounding factors.

RESULTS

Hundred eyes of 50 patients were evaluated in each group. Only three patients in group 1 had non-proliferative retinopathy. The median duration of rheumatic disease was 9 years, whereas that of diabetes was 11 years. The mean duration of anti-TNF therapy was 4 years. In the control group of diabetes-only patients, 13 patients developed some form of newly diagnosed diabetic retinopathy during the last five years. The calculated retinopathy occurrence between the groups was statistically significant (p < 0.05). In this study, the incidence rate ratio for patients receiving anti-TNF treatment was calculated as 0.4 in the study.

CONCLUSION

TNF inhibitors, with their anti-inflammatory effects, positively impact diabetic complications by reducing the incidence of retinopathy. To our knowledge, this is the first study to evaluate retinopathy development after anti-TNF therapy.

Serum autoantibodies against hexokinase 1 manifest secondary to diabetic macular edema onset

AIMS

Autoantibodies against hexokinase 1 (HK1) were recently proposed to be associated with diabetic macular edema (DME). We hypothesized that anti-HK1 autoantibodies can be used as DME markers and to predict DME onset.

MATERIALS AND METHODS

Serum from patients with 1) DME, 2) diabetes mellitus (DM), 3) allergies or autoimmunities, and 4) control subjects was tested for anti-HK1 and anti-hexokinase 2 (HK2) autoantibodies by immunoblotting. Patients with DM were prospectively followed for up to nine years, and the association of anti-HK1 antibodies with new-onset DME was evaluated. The vitreous humor was also tested for autoantibodies.

RESULTS

Among patients with DME, 32 % were positive for anti-HK1 autoantibodies (42 % of those with underlying type 1 DM and 31 % of those with underlying type 2 DM), and 12 % were positive for anti-HK2 autoantibodies, with only partial overlap of these two groups of patients. Anti-HK1 positive were also 7 % of patients with DM, 6 % of patients with allergies and autoimmunities, and 3 % of control subjects. The latter three groups were anti-HK2 negative. Only one of seven patients with DM who were initially anti-HK1 positive developed DME.

CONCLUSIONS

Anti-HK1 autoantibodies can be used as DME markers but fail to predict DME onset.

Prevalence and associated factors of proliferative diabetic retinopathy among adult diabetic patients in Northwest Ethiopia, 2023: A cross-sectional multicenter study

BACKGROUND

Proliferative diabetic retinopathy is one of the advanced complications of diabetic retinopathy. If left untreated, almost all eyes could lose a significant portion of their vision within four months. There is limited evidence regarding the magnitude of proliferative diabetic retinopathy and associated factors in the study setting and also in Ethiopia.

PURPOSE

To determine the magnitude and associated factors of proliferative diabetic retinopathy among adult diabetic patients attending Specialized Comprehensive Hospital-Diabetic Care Clinics in Northwest Ethiopia, 2023.

METHODS

A multicenter, hospital-based, cross-sectional study was conducted on 1219 adult diabetic patients selected by systematic random sampling technique. Data were collected through an in-person interview and physical examination. The Statistical Package for Social Science Version 20 was used to analyze the data. Logistic regression methods were used to test the association between predisposing factors and proliferative diabetic retinopathy. The adjusted odds ratio with a 95% confidence interval was used to determine the strength of association.

RESULTS

The prevalence of proliferative diabetic retinopathy was 3.1% (95% CI: 2.10%-4.10%). Hypertension (AOR = 4.35 (95% CI: 1.87-10.12)), peripheral neuropathy (AOR = 3.87 (95% CI: 1.57-9.54)), nephropathy (AOR = 2.58 (95% CI: 1.13-5.87)), ≥10 years duration of diabetes mellitus (AOR = 5.30 (95% CI: 2.32-12.14)), insulin use (AOR = 3.07 (95% CI: 1.08-8.68)), and poor adherence to diabetes mellitus medications (AOR = 3.77 (95% CI: 1.64-8.64)) were confirmed to have statistically significant association with proliferative diabetic retinopathy.

CONCLUSION

The prevalence of proliferative diabetic retinopathy among adult diabetic patients in the diabetes clinic was higher than the global study. Hypertension, peripheral neuropathy, nephropathy, ≥10 year's duration of diabetic mellitus, insulin use and poor adherence to diabetes mellitus medications were among the factors significantly associated with proliferative diabetic retinopathy.

Associated factors of diabetic retinopathy in type 1 and 2 diabetes in Limpopo province in South Africa

Background

Diabetic retinopathy (DR) is the major cause of vision impairment or blindness in individuals who have diabetes. It has accounted for 2.6% of all cases of blindness, and 1.9% of all cases of vision impairments globally. There is a lack of data on the prevalence of diabetic retinopathy and its associated factors amongst diabetic rural populations. Hence, the current study aimed to determine factors associated with diabetic retinopathy (DR) among diabetes mellitus (DM) patients undergoing diabetic therapy.

Methods

The study was cross-sectional in design and the participants were selected using convenient sampling. STATA version 15 software was used for data analysis. Chi-square was used to compare proportions. Logistic regression was used to determine the relationship between DR and associated risk factors.

Results

The prevalence of DR was 35.3%, of which 32% were mild and 3.4% were moderate non-proliferative DR (NPDR). Females were more unemployed than males (32.1% versus 16.8%, p=0.0058). Males were found to drink alcohol (21.8% versus 1.9%, p<0.001) and smoke cigarettes (4% versus 0.3%, p=0.0034) more than females. Being aged ≥ 55 years (OR: 2.7, 95% CI: 1.6-4.4), with matric qualification (OR: 0.6; 95% CI: 0.4-1.0); employed (OR: 1.4, 95% CI: 1.2-1.6); having high systolic blood pressure (OR=1.4, 95%CI=1.1-1.7) were the independent determinants of DR.

Conclusions

The prevalence of diabetic retinopathy was 34%. DR was determined by high systolic blood pressure, old age, and employment. Although not statistically significant, gender, hyperglycemic state, poor glycemic control, smoking, and increased body mass index (BMI) were associated with increased risk of developing DR.

Acute and Chronic Adverse Outcomes of Type 1 Diabetes

Type 1 diabetes is associated with both acute and chronic complications. Acute complications include diabetic ketoacidosis and severe hypoglycemia. Chronic complications can be microvascular or macrovascular. Microvascular complications include retinopathy, nephropathy, and neuropathy. The pathophysiology of microvascular complications is complex. Hyperglycemia is a common underlying risk factor, underscoring the importance of optimizing glycemic management. Patients with type 1 diabetes are also at increased risk of macrovascular complications including coronary artery disease and vascular disease. The American Diabetes Association provides screening guidelines for chronic complications of diabetes. Adherence to these guidelines is an important aspect of diabetes care.

Hexokinase-linked glycolytic overload and unscheduled glycolysis in hyperglycemia-induced pathogenesis of insulin resistance, beta-cell glucotoxicity, and diabetic vascular complications

Hyperglycemia is a risk factor for the development of insulin resistance, beta-cell glucotoxicity, and vascular complications of diabetes. We propose the hypothesis, hexokinase-linked glycolytic overload and unscheduled glycolysis, in explanation. Hexokinases (HKs) catalyze the first step of glucose metabolism. Increased flux of glucose metabolism through glycolysis gated by HKs, when occurring without concomitant increased activity of glycolytic enzymes-unscheduled glycolysis-produces increased levels of glycolytic intermediates with overspill into effector pathways of cell dysfunction and pathogenesis. HK1 is saturated with glucose in euglycemia and, where it is the major HK, provides for basal glycolytic flux without glycolytic overload. HK2 has similar saturation characteristics, except that, in persistent hyperglycemia, it is stabilized to proteolysis by high intracellular glucose concentration, increasing HK activity and initiating glycolytic overload and unscheduled glycolysis. This drives the development of vascular complications of diabetes. Similar HK2-linked unscheduled glycolysis in skeletal muscle and adipose tissue in impaired fasting glucose drives the development of peripheral insulin resistance. Glucokinase (GCK or HK4)-linked glycolytic overload and unscheduled glycolysis occurs in persistent hyperglycemia in hepatocytes and beta-cells, contributing to hepatic insulin resistance and beta-cell glucotoxicity, leading to the development of type 2 diabetes. Downstream effector pathways of HK-linked unscheduled glycolysis are mitochondrial dysfunction and increased reactive oxygen species (ROS) formation; activation of hexosamine, protein kinase c, and dicarbonyl stress pathways; and increased Mlx/Mondo A signaling. Mitochondrial dysfunction and increased ROS was proposed as the initiator of metabolic dysfunction in hyperglycemia, but it is rather one of the multiple downstream effector pathways. Correction of HK2 dysregulation is proposed as a novel therapeutic target. Pharmacotherapy addressing it corrected insulin resistance in overweight and obese subjects in clinical trial. Overall, the damaging effects of hyperglycemia are a consequence of HK-gated increased flux of glucose metabolism without increased glycolytic enzyme activities to accommodate it.

Small-molecule agonist AdipoRon alleviates diabetic retinopathy through the AdipoR1/AMPK/EGR4 pathway

BACKGROUND

Diabetes mellitus (DM) is a progressive disease that involves multiple organs due to increased blood glucose, and diabetic retinopathy (DR) is the main complication of DM in the eyes and causes irreversible vision loss. In the pathogenesis of diabetic vascular disease, oxidative stress caused by hyperglycemia plays an important role in Müller cell impairment. In recent years, AdipoRon, an adiponectin analog that demonstrated important physiological functions in obesity, diabetes, inflammation, and cardiovascular diseases, demonstrated cellular protection from apoptosis and reduced inflammatory damage through a receptor-dependent mechanism. Here, we investigated how AdipoRon reduced oxidative stress and apoptosis in Müller glia in a high glucose environment.

RESULTS

By binding to adiponectin receptor 1 on Müller glia, AdipoRon activated 5' adenosine monophosphate-activated protein kinase (AMPK)/acetyl-CoA carboxylase phosphorylation downstream, thereby alleviating oxidative stress and eventual apoptosis of cells and tissues. Transcriptome sequencing revealed that AdipoRon promoted the synthesis and expression of early growth response factor 4 (EGR4) and inhibited the cellular protective effects of AdipoRon in a high-glucose environment by reducing the expression of EGR4. This indicated that AdipoRon played a protective role through the EGR4 and classical AMPK pathways.

CONCLUSIONS

This provides a new target for the early treatment of DR.

Association between Gut Microbiota Compositions with MicrovascularComplications in Individuals with Diabetes: A Systematic Review

BACKGROUND

Diabetes is one of the chronic and very complex diseases that can lead to microvascular complications. Recent evidence demonstrates that dysbiosis of the microbiota composition might result in low-grade, local, and systemic inflammation, which contributes directly to the development of diabetes mellitus and its microvascular consequences.

OBJECTIVE

The aim of this systematic review was to investigate the association between diabetes microvascular complications, including retinopathy, neuropathy, nephropathy, and gut microbiota composition.

METHODS

A systematic search was carried out in PubMed, Scopus, and ISI Web of Science from database inception to March 2023. Screening, data extraction, and quality assessment were performed by two independent authors. The Newcastle-Ottawa Quality Assessment Scale was used for quality assessment.

RESULTS

About 19 articles were selected from 590 retrieved articles. Among the included studies, nephropathy has been studied more than other complications of diabetes, showing that the composition of the healthy microbiota is changed, and large quantities of uremic solutes that cause kidney injury are produced by gut microbes. Phyla, including Fusobacteria and Proteobacteria, accounted for the majority of the variation in gut microbiota between Type 2 diabetic patients with and without neuropathy. In cases with retinopathy, an increase in pathogenic and proinflammatory bacteria was observed.

CONCLUSION

Our results revealed that increases in Bacteroidetes, Proteobacteria and Fusobacteria may be associated with the pathogenesis of diabetic nephropathy, neuropathy, and retinopathy. In view of the detrimental role of intestinal dysbiosis in the development of diabetes-related complications, gut microbiota assessment may be used as a biomarker in the future and interventions that modulate the composition of microbiota in individuals with diabetes can be used to prevent and control these complications.

A Robust Machine Learning Model for Diabetic Retinopathy Classification

Ensemble learning is a process that belongs to the artificial intelligence (AI) field. It helps to choose a robust machine learning (ML) model, usually used for data classification. AI has a large connection with image processing and feature classification, and it can also be successfully applied to analyzing fundus eye images. Diabetic retinopathy (DR) is a disease that can cause vision loss and blindness, which, from an imaging point of view, can be shown when screening the eyes. Image processing tools can analyze and extract the features from fundus eye images, and these corroborate with ML classifiers that can perform their classification among different disease classes. The outcomes integrated into automated diagnostic systems can be a real success for physicians and patients. In this study, in the form image processing area, the manipulation of the contrast with the gamma correction parameter was applied because DR affects the blood vessels, and the structure of the eyes becomes disorderly. Therefore, the analysis of the texture with two types of entropies was necessary. Shannon and fuzzy entropies and contrast manipulation led to ten original features used in the classification process. The machine learning library PyCaret performs complex tasks, and the empirical process shows that of the fifteen classifiers, the gradient boosting classifier (GBC) provides the best results. Indeed, the proposed model can classify the DR degrees as normal or severe, achieving an accuracy of 0.929, an F1 score of 0.902, and an area under the curve (AUC) of 0.941. The validation of the selected model with a bootstrap statistical technique was performed. The novelty of the study consists of the extraction of features from preprocessed fundus eye images, their classification, and the manipulation of the contrast in a controlled way.

Underlying mechanisms of diabetes knowledge influencing diabetes self-management behaviors among patients with type II diabetes in rural China: Based on health belief model

OBJECTIVE

To investigate the association between diabetes knowledge and diabetes self-management (DSM) behaviors and to explore the influence mechanism between them among patients with type 2 diabetes mellitus (T2DM) based on health belief model in rural China.

METHODS

This cross-sectional study included 483 participants with T2DM from 8 villages of 3 townships in Jiangsu Province. All participants completed a structured questionnaire, including demographic information, diabetes knowledge, DSM behaviors, health beliefs, and cognitive function. Multiple linear regression and mediation analysis were performed to analyze the association between diabetes knowledge and DSM behaviors, furthermore the mechanism between them.

RESULTS

Diabetes knowledge and self-efficacy positively influenced DSM behaviors. Health beliefs multiply mediated the association between diabetes knowledge and DSM behaviors. Perceived behavioral barriers mediated the relationship between diabetes knowledge and DSM behaviors, where a suppression effect existed. A chain-mediated effect was found: diabetes knowledge affected perceived benefits, followed by self-efficacy, and finally DSM behaviors.

CONCLUSION

Diabetes knowledge acquisition played an important role in improving DSM behaviors, and health beliefs multiply mediated the relationship between them.

PRACTICE IMPLICATIONS

When designing interventions, health systems and health providers should refocus on diabetes knowledge, emphasize the benefits of self-management, and consider the barriers that patients may encounter.

Efficacy and Safety of Brolucizumab for Diabetic Macular Edema: The KINGFISHER Randomized Clinical Trial

Importance

Despite the effectiveness of existing anti-vascular endothelial growth factor (VEGF) therapies, a need remains for further treatment options to improve response rates and/or reduce injection or monitoring frequency in patients with diabetic macular edema (DME).

Objective

To evaluate the efficacy and safety of brolucizumab vs aflibercept dosed every 4 weeks in participants with DME.

Design, Participants, and Setting

This 52-week, double-masked, phase 3 randomized clinical trial included treatment-naive adults and adults who had previously received anti-VEGF therapy. Data were collected from September 2019 to March 2020, and data were analyzed from April 2020 to February 2021.

Intervention

Brolucizumab, 6 mg, intravitreal injection every 4 weeks or aflibercept, 2 mg, intravitreal injection every 4 weeks.

Main Outcomes and Measures

Participants were randomized 2:1 to brolucizumab, 6 mg, or aflibercept, 2 mg. The primary end point was change from baseline in best-corrected visual acuity at week 52. Secondary end points were the proportion of participants with a 2-step improvement or greater from baseline in Diabetic Retinopathy Severity Scale score, the proportion of eyes with absence of both subretinal fluid and intraretinal fluid, change from baseline in central subfield thickness, and safety at week 52.

Results

A total of 517 participants were randomized to brolucizumab (n = 346) or aflibercept (n = 171); 299 (57.8%) were male, and the mean (SD) age was 60.7 (10.2) years. Brolucizumab was noninferior to aflibercept in best-corrected visual acuity (Early Treatment Diabetic Retinopathy Study letter score) change from baseline at week 52 (brolucizumab, 12.2-letter improvement; aflibercept, 11.0-letter improvement; difference, 1.1; 95% CI, -0.6 to 2.9; noninferiority margin, 4; P < .001). Brolucizumab was superior to aflibercept for the proportion of eyes without subretinal and intraretinal fluid (brolucizumab, 144 of 346 [41.6%]; aflibercept, 38 of 171 [22.2%]; difference, 20.0%; 95% CI, 12.5to 28.6; P < .001) and mean central subfield thickness change from baseline at week 52 (brolucizumab, -237.8 μm; aflibercept, -196.5 μm; difference, -41.4; 95% CI, -58.9 to -23.8; P < .001). Incidence of intraocular inflammation was 4.0% (14 of 346) in the brolucizumab arm and 2.9% (5 of 171) in the aflibercept arm, incidence of retinal vasculitis was 0.9% (3 of 346) and 0.6% (1 of 171), respectively, and incidence of retinal vascular occlusion was 0.3% (1 of 346) and 0.6% (1 of 171). One participant in the brolucizumab arm had retinal artery occlusion.

Conclusions and Relevance

In these study participants with DME, no clinically meaningful differences in visual outcomes were noted between the brolucizumab and aflibercept arms; some superior anatomic improvements were noted in the brolucizumab arm. No new safety concerns were identified.

Trial Registration

ClinicalTrials.gov Identifier: NCT03917472.

Predicting the risk of diabetic retinopathy using explainable machine learning algorithms

BACKGROUND AND OBJECTIVE

Diabetic retinopathy (DR) is a global health concern among diabetic patients. The objective of this study was to propose an explainable machine learning (ML)-based system for predicting the risk of DR.

MATERIALS AND METHODS

This study utilized publicly available cross-sectional data in a Chinese cohort of 6374 respondents. We employed boruta and least absolute shrinkage and selection operator (LASSO) based feature selection methods to identify the common predictors of DR. Using the identified predictors, we trained and optimized four widly applicable models (artificial neural network, support vector machine, random forest, and extreme gradient boosting (XGBoost) to predict patients with DR. Moreover, shapely additive explanation (SHAP) was adopted to show the contribution of each predictor of DR in the prediction.

RESULTS

Combining Boruta and LASSO method revealed that community, TCTG, HDLC, BUN, FPG, HbAlc, weight, and duration were the most important predictors of DR. The XGBoost-based model outperformed the other models, with an accuracy of 90.01%, precision of 91.80%, recall of 97.91%, F1 score of 94.86%, and AUC of 0.850. Moreover, SHAP method showed that HbA1c, community, FPG, TCTG, duration, and UA1b were the influencing predictors of DR.

CONCLUSION

The proposed integrating system will be helpful as a tool for selecting significant predictors, which can predict patients who are at high risk of DR at an early stage in China.

Alleviate oxidative stress in diabetic retinopathy: antioxidant therapeutic strategies

OBJECTIVES

This review outlines the function of oxidative stress in DR and discusses therapeutic strategies to treat DR with antioxidants.

METHODS

Published papers on oxidative stress in DR and therapeutic strategies to treat DR with antioxidants were collected and reviewed via database searching on PubMed.

RESULTS

The abnormal development of DR is a complicated process. The pathogenesis of DR has been reported to involve oxidative stress, despite the fact that the mechanisms underlying this are still not fully understood. Excessive reactive oxygen species (ROS) accumulation can damage retina, eventually leading to DR. Increasing evidence have demonstrated that antioxidant therapy can alleviate the degeneration of retinal capillaries in DR.

CONCLUSION

Oxidative stress can play an important contributor in the pathogenesis of DR. Furthermore, animal experiments have shown that antioxidants are a beneficial therapy for treating DR, but more clinical trial data is needed.

Endothelial progenitor cells as biomarkers of diabetes-related cardiovascular complications

Diabetes mellitus (DM) constitutes a chronic metabolic disease characterized by elevated levels of blood glucose which can also lead to the so-called diabetic vascular complications (DVCs), responsible for most of the morbidity, hospitalizations and death registered in these patients. Currently, different approaches to prevent or reduce DM and its DVCs have focused on reducing blood sugar levels, cholesterol management or even changes in lifestyle habits. However, even the strictest glycaemic control strategies are not always sufficient to prevent the development of DVCs, which reflects the need to identify reliable biomarkers capable of predicting further vascular complications in diabetic patients. Endothelial progenitor cells (EPCs), widely known for their potential applications in cell therapy due to their regenerative properties, may be used as differential markers in DVCs, considering that the number and functionality of these cells are affected under the pathological environments related to DM. Besides, drugs commonly used with DM patients may influence the level or behaviour of EPCs as a pleiotropic effect that could finally be decisive in the prognosis of the disease. In the current review, we have analysed the relationship between diabetes and DVCs, focusing on the potential use of EPCs as biomarkers of diabetes progression towards the development of major vascular complications. Moreover, the effects of different drugs on the number and function of EPCs have been also addressed.

Optical coherence tomography angiography in diabetic retinopathy

There remain many unanswered questions on how to assess and treat the pathology and complications that arise from diabetic retinopathy (DR). Optical coherence tomography angiography (OCTA) is a novel and non-invasive three-dimensional imaging method that can visualize capillaries in all retinal layers. Numerous studies have confirmed that OCTA can identify early evidence of microvascular changes and provide quantitative assessment of the extent of diseases such as DR and its complications. A number of informative OCTA metrics could be used to assess DR in clinical trials, including measurements of the foveal avascular zone (FAZ; area, acircularity, 3D para-FAZ vessel density), vessel density, extrafoveal avascular zones, and neovascularization. Assessing patients with DR using a full-retinal slab OCTA image can limit segmentation errors and confounding factors such as those related to center-involved diabetic macular edema. Given emerging data suggesting the importance of the peripheral retinal vasculature in assessing and predicting DR progression, wide-field OCTA imaging should also be used. Finally, the use of automated methods and algorithms for OCTA image analysis, such as those that can distinguish between areas of true and false signals, reconstruct images, and produce quantitative metrics, such as FAZ area, will greatly improve the efficiency and standardization of results between studies. Most importantly, clinical trial protocols should account for the relatively high frequency of poor-quality data related to sub-optimal imaging conditions in DR and should incorporate time for assessing OCTA image quality and re-imaging patients where necessary.

Prevalence and associated factors of diabetic retinopathy among people with diabetes screened using fundus photography at a community diabetic retinopathy screening program in Nepal

BACKGROUND

This study aimed to assess the prevalence and associated factors of diabetic retinopathy (DR) and vision threatening DR (VTDR) among people with diabetes screened using fundus photography in Nepal.

METHODS

This is a retrospective study among people with diabetes presented for DR screening using fundus photography from 2013 to 2019. Detailed demographics, duration of diabetes, medical history, visual acuity, and grading of DR on fundus photography were analyzed. Fundus camera used in the study were;Topcon digital fundus camera 900 CXR and digital portable fundus cameras (Nidek-10 portable non-mydriatric fundus camera; Versacam & Trade & Alpha, France), and a Zeiss portable fundus camera (Zeiss Visucout 100). Macula centred and disc centred 45 degree two images were taken from each eye. Pupil were dilated in cases where there was media haze in un-dilated cases. DR was graded using early treatment diabetic retinopathy study criteria. The images were graded by fellowship trained retina specialist. DR prevalence included any DR changes in one or both eyes.

RESULTS

Total of 25,196 patients with diabetes were enrolled. Mean age was 54.2 years with Standard Deviation (S.D):12.9 years, ranging from 6 years to 97 years. Type 1 and type 2 diabetes comprised of 451 people (1.79%) and 24,747 (98.21%) respectively. Overall, 1.8% of the images were un-gradable. DR prevalence was 19.3% (95% Confidence Interval (CI): 18.8 - 19.7%). DR prevalence in type 1 and type 2 diabetes was 15.5% (95% CI: 12.5 - 18.6%) and 19.3% (CI: 18.8 - 19.8%) respectively. Clinically significant macular edema (CSME) was found in 5.9% (95% CI: 5.6-6.2%) and VTDR in 7.9% (95% CI: 7.7-8.3%). In multivariate analysis, our study revealed strong evidence to suggest that there is meaningful association between DR and VTDR with duration of diabetes, diabetic foot, diabetic neuropathy, agriculture occupation, those under oral hypoglycaemic agents or insulin or both as compared to those under diet only, and presenting visual acuity > 0.3LogMAR.

CONCLUSION

Prevalence and associated factors for DR and VTDR were similar to other DR screening programs in the region. Emphasis on wider coverage of DR screening could help for timely detection and treatment of STDR to avoid irreversible blindness.

Efficacy and safety of pan retinal photocoagulation combined with intravitreal anti-VEGF agents for high-risk proliferative diabetic retinopathy: A systematic review and meta-analysis

BACKGROUND

High-risk proliferative diabetic retinopathy (HR-PDR) is the advanced stage of diabetic retinopathy progression with poor prior treatment efficacy and high rates of blindness. This meta-analysis aims to compare the efficacy and safety of pan retinal photocoagulation (PRP) combined with intravitreal anti-vascular endothelial growth factor (aVEGF) (PRP + aVEGF) versus PRP monotherapy in HR-PDR patients.

METHODS

A thorough search was performed through PubMed, Web of Science, EMBASE, and the Cochran Library from inception to December 18, 2022. Outcome measures included change in central macular thickness, best-corrected visual acuity, fluorescein angiography, incidence of undergoing vitrectomy, and adverse events during the follow-up period.

RESULTS

Eight studies (6 randomized controlled trials and 2 retrospective studies) with 375 eyes were included in this meta-analysis. There were no obvious differences in the changes of best-corrected visual acuity and fluorescein angiography between the PRP + aVEGF and PRP monotherapy groups. However, PRP + aVEGF group had a significant reduction in the change of central macula thickness (standard mean deviations = -1.44, 95%CI = -2.55 to -0.32, P = .01) and the rate of undergoing vitrectomy (odds ratio = 0.20, 95%CI = 0.05-0.83, P = .01). Additionally, the risks of vitreous hemorrhage and other complications were not significantly different between the 2 groups.

CONCLUSION SUBSECTIONS

Our meta-analysis indicated that PRP + aVEGF might have potential benefits in the treatment of HR-PDR patients. However, given several limitations of this study, more research is needed to confirm our findings.

Isolation of phenolic compound from Lawsonia inermis and its prediction as anti-diabetic agent using molecular docking and molecular dynamic simulation

High blood sugar is a defining feature of chronic disease, diabetes mellitus (DM). There are numerous commercially available medications for the treatment of DM. However, managing the patient's glucose levels remain a challenge because of the gradual reduction in beta-cell function and some side effects from the long-term use of various medications. Previous research has shown that the phenolic compound of henna plant (Lawsonia inermis L.) has the potential as anti-diabetic agent since it is able to suppress the digesting of α-amylase enzyme. In these studies, the plant' phenolic compounds have been isolated and characterized using UV, IR, NMR and LC-MS methods. Furthermore, the compound interaction into the active site of the α-amylase enzyme has been analyzed using molecular docking and molecular dynamics, as well as into α-glucosidase enzyme for predicting of the affinities. The results showed that isolated compound has the molecular formula of C15H10O6 with eleven degrees of unsaturation (DBE; double bond equivalence). The DBE value corresponds to the structure of the luteolin compound having an aromatic ring (8), a carbonyl group on the side chain (1) and a ketone ring with (2). The interaction study of the isolated compound with α-amylase and α-glucosidase enzyme using molecular docking compared to the positive control (acarbose) gave binding energy of -8.03 and -8.95 kcal/mol, respectively. The molecular dynamics simulation using the MM-PBSA method, complex stability based on solvent accessible surface area (SASA), root mean square deviation (RMSD), and root mean square fluctuation (RMSF) revealed that the compound has a high affinity for receptors. The characteristics of skin permeability, absorption, and distribution using ADME-Tox model were also well predicted. The results indicate that the phenolic compound isolated from L. inermis leaf was luteolin and it has the potential as an anti-diabetic agent.Communicated by Ramaswamy H. Sarma.

The Warburg effect alters amino acid homeostasis in human retinal endothelial cells: implication for proliferative diabetic retinopathy

Proliferative diabetic retinopathy (PDR) remains a leading cause of blindness despite progress in screening and treatment. Recently, the Warburg effect, a metabolic alteration affecting amino acid (AA) metabolism in proliferating cells, has drawn attention regarding its role in PDR. This study aimed to investigate the impact of the Warburg effect on AA metabolism in human retinal endothelial cells (HRECs) subjected to PDR-associated risk factors and validate the findings in patients with PDR. In vitro experiments exposed HRECs to high glucose (HG) and/or hypoxia (Hyp), known inducers of the Warburg effect. The HG + Hyp group of HRECs exhibited significant differences in non-essential AAs with aliphatic non-polar side chains, mainly driven by elevated glycine concentrations. Pathway enrichment analysis revealed several glycine metabolism-related pathways significantly altered due to the Warburg effect induced by HG + Hyp. Crucially, vitreous humor samples from PDR patients displayed higher glycine levels compared to non-diabetic and diabetic patients without PDR. The odds ratio for PDR patients with glycine levels above the cut-off of 0.0836 µM was 28 (p = 0.03) compared to non-PDR controls. In conclusion, this study provides mechanistic insights into how a specific Warburg effect subtype contributes to glycine accumulation in PDR and supports glycine's potential as a biomarker for PDR pathogenesis.

Clinical and Translational Imaging and Sensing of Diabetic Microangiopathy: A Narrative Review

Microvascular changes in diabetes affect the function of several critical organs, such as the kidneys, heart, brain, eye, and skin, among others. The possibility of detecting such changes early enough in order to take appropriate actions renders the development of appropriate tools and techniques an imperative need. To this end, several sensing and imaging techniques have been developed or employed in the assessment of microangiopathy in patients with diabetes. Herein, we present such techniques; we provide insights into their principles of operation while discussing the characteristics that make them appropriate for such use. Finally, apart from already established techniques, we present novel ones with great translational potential, such as optoacoustic technologies, which are expected to enter clinical practice in the foreseeable future.

Prevalence of diabetic retinopathy in patients with diabetes in Alexandria and North-West Delta, Egypt

PURPOSE

The purpose of this research was to estimate the prevalence of DR in Alexandria and the North-West Delta region.

METHODS

All diabetic patients attending the general ophthalmology clinics (Group 1), diabetic internal medicine clinics (Group 2), or reached out in the local communities (Group 3) were eligible to participate. Fundus photographs were graded according to the Scottish DR grading system by three independent UK-certified graders. Adjudication by a consultant was done when needed.

RESULTS

Out of 11,033 screened patients, 10,811 had a gradable fundus photograph in at least one eye and were included. The numbers of cases in groups 1, 2 and 3 were 3940, 2826, and 4045, respectively. Males represented 38.35% of the cases. Mean age was 55 ± 12.63. For the whole sample, groups 1, 2 and 3, the DR prevalence was 32.49, 46.4%, 29.13%, and 21.29%, respectively. The prevalence of proliferative DR (grade R4) was 6.16%, 11.83%, 5.02%, and 1.45%, respectively, and of referable maculopathy (Grade M2) was 19.95%, 31.42%, 15.92%, and 11.59%, respectively. In univariate analysis, older age, higher random blood glucose, and longer DM duration were associated with a higher risk of both DR and referable diabetic maculopathy. This association was maintained in multivariate analysis for the high random blood glucose level and the longer duration of DM (but not for the older age).

CONCLUSION

A significantly higher prevalence of DR, grades R4 and M2 was found in the hospital-recruited patients than in diabetics from the local communities.

Prevalence of diabetic retinopathy and reduced vision among indigenous Australians in the nurse-led integrated Diabetes Education and Eye Screening study in a regional primary care clinic

BACKGROUND

Nationally, Indigenous Australians are more likely to have diabetes and diabetic retinopathy (DR) than non-Indigenous Australians. However, the prevalence of DR and impaired vision in regional primary care settings is unclear.

AIM

To describe the prevalence and severity of DR and presenting vision level among Indigenous Australian adults with diabetes attending an indigenous primary care clinic in regional Australia.

METHODS

Participants underwent nurse-led retinal imaging and DR screening with offsite retinal grading in the integrated Diabetes Education and Eye Screening (iDEES) project implemented at a regional indigenous primary healthcare setting between January 2018 and March 2020.

RESULTS

Of 172 eligible adults, 135 (79%) were recruited and screened for DR and vision level. The median age was 56 (46-67) years, 130 (96%) had type 2 diabetes of median (interquartile range) duration 6 (2-12) years and 48 (36%) were male. Images from 132 (97.8%) participants were gradable. DR was present in 38 (29%) participants: mild non-proliferative in 33 (25%); moderate-severe in three (2.5%); and sight-threatening two (1.5%). Subnormal presenting vision was present in 33%.

CONCLUSIONS

A nurse-led model of care integrating diabetes eye screening and education at a single visit was successful at recruiting Indigenous Australian adults with diabetes, screening their vision and acquiring a high rate of gradable images. Even for a short duration of known diabetes, DR was present in three out of 10 patients screened.

Serum disease-specific IgG Fc glycosylation as potential biomarkers for nonproliferative diabetic retinopathy using mass spectrometry

OBJECTIVE

To explore the potential of serum disease-specific immunoglobulin G (DSIgG) glycosylation as a biomarker for the diagnosis of nonproliferative diabetic retinopathy (NPDR).

METHODS

A total of 387 consecutive diabetic patients presenting in an eye clinic without proliferative diabetic retinopathy (DR) were included and divided into those with nondiabetic retinopathy (NDR) (n = 181) and NPDR (n = 206) groups. Serum was collected from all patients for DSIgG separation. The enriched glycopeptides of the tryptic digests of DSIgG were detected using matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS). Patients were randomly divided into discovery and validation sets (1:1). The differences in glycopeptide ratios between the groups were compared by using Student's t-test or the Mann-Whitney U test. The predictive ability of the model was assessed using the area under the receiver operating characteristic curve (AUC).

RESULTS

DSIgG1 G1FN/G0FN, G2N/G2, G2FN/G2N and DSIgG2 G1F/G0F, G1FN/G0FN, G2N/G1N, G2S/G2 were significantly different between NDR and NPDR patients (p < 0.05) in both the discovery and validation sets. The prediction model that was built comprising the seven glycopeptide ratios showed good NPDR prediction performance with an AUC of 0.85 in the discovery set and 0.87 in the validation set.

CONCLUSION

DSIgG Fc N-glycosylation ratios were associated with NPDR and can be used as potential biomarkers for the early diagnosis of DR.

'I don`t need an eye check-up'. A qualitative study using a behavioural model to understand treatment-seeking behaviour of patients with sight threatening diabetic retinopathy (STDR) in India

Diabetic Retinopathy (DR) affects about 27% of patients with diabetes globally. According to the World Health Organization (WHO), DR is responsible for37 million cases of blindness worldwide. The SMART India study (October 2020-August 2021) documented the prevalence of diabetes, and DR in people40 years and above across ten Indian states and one Union Territory by conducting community screening. About 90% of people with sight threatening diabetic retinopathy (STDR) were referred from this screening study to eye hospitals for management, but failed to attend. This qualitative study, a component of the SMART India study, explored perceptions of referred patients regarding their susceptibility to eye related problems in diabetes and the benefits/barriers to seeking care. Perceived barriers from the viewpoint of ophthalmologists were also explored. Guided by the Health Beliefs Model (HBM), 20 semi structured interviews were carried out with consenting patients diagnosed with STDR. They included nine patients who had sought care recruited from eight eye hospitals across different states in India and eleven patients who did not seek care. Eleven ophthalmologists also participated. Four themes of analysis based on the HBM were, understanding of DR and its treatment, perceptions about susceptibility and severity, perceived barriers, perceived benefits and cues to action. Findings revealed poor understanding of the effects of diabetes on the eye contributing to low risk perception. Prohibitive costs of treatment, difficulties in accessing care services and poor social support were major barriers to seeking care. Ophthalmologists acknowledged that the absence of symptoms and the slow progressive nature of the disease deluded patients into thinking that they were fine. The study attests to the need for greater health literacy around diabetes, DR and STDR; for making treatment more affordable and accessible and for the development of effective patient education and communication strategies towards increasing compliance.

Determinants of diabetic retinopathy in Ethiopia: A systematic review and meta-analysis

INTRODUCTION

Diabetic retinopathy (DR) is the primary retinal vascular complication of diabetes mellitus and a leading cause of visual impairment and blindness. It affects the global diabetic population. In Ethiopia, about one-fifth of diabetic patients were affected by DR, but there were inconsistent finding across studies about the determinants factors of DR. Therefore, we aimed to identify the risk factors for DR among diabetic patients.

METHODS

We have accessed previous studies through an electronic web-based search strategy using PubMed, Google (Scholar), the Web of Science, and the Cochrane Library with a combination of search terms. The quality of each included article was assessed using the Newcastle Ottawa Assessment Scale. All statistical analyses were carried out using Stata version 14 software. The odds ratios of risk factors were pooled using a fixed-effect meta-analysis model. Heterogeneity was assessed using the Cochrane Q statistics and I-Square (I2). Furthermore, publication bias was detected based on the graphic asymmetry test of the funnel plot and/or Egger's test (p< 0.05).

RESULTS

The search strategy retrieved 1285 articles. After the removal of duplicate articles, 249 articles remained. Following further screening, about 18 articles were assessed for eligibility, of which three articles were excluded because of reporting without the outcome of interest, poor quality, and not full text. Finally, fifteen studies were reviewed for the final analysis. Co-morbid hypertension (HTN) (AOR 2.04, 95%CI: 1.07, 3.89), poor glycemic control (AOR = 4.36, 95%CI: 1.47, 12.90), and duration of diabetes illness (AOR = 3.83, 95%CI: 1.17, 12.55) were found to be confirmed associated factors of diabetic retinopathy.

CONCLUSION

In this study, co-morbid HTN, poor glycemic control, and longer duration of diabetes illness were found to be the determinant factors of DR. Aggressive treatment of co-morbid HTN and blood glucose, and regular eye screening should be implemented to reduce the occurrence of DR.

TRIAL REGISTRATION

The review protocol was registered in the international prospective register of systematic reviews (PROSPERO) with registration number PROSPERO: CRD42023416724.

Retinal Cell Damage in Diabetic Retinopathy

Diabetic retinopathy (DR), the most common microvascular complication that occurs in diabetes mellitus (DM), is the leading cause of vision loss in working-age adults. The prevalence of diabetic retinopathy is approximately 30% of the diabetic population and untreated DR can eventually cause blindness. For decades, diabetic retinopathy was considered a microvascular complication and clinically staged by its vascular manifestations. In recent years, emerging evidence has shown that diabetic retinopathy causes early neuronal dysfunction and neurodegeneration that may precede vascular pathology and affect retinal neurons as well as glial cells. This knowledge leads to new therapeutic strategies aiming to prevent dysfunction of retinal neurons at the early stage of DR. Early detection and timely treatment to protect retinal neurons are critical to preventing visual loss in DR. This review provides an overview of DR and the structural and functional changes associated with DR, and discusses neuronal degeneration during diabetic retinopathy, the mechanisms underlying retinal neurodegeneration and microvascular complications, and perspectives on current and future clinic therapies.

Predictive factors for treatment outcomes with intravitreal anti-vascular endothelial growth factor injections in diabetic macular edema in clinical practice

BACKGROUND

Intravitreal anti-vascular endothelial growth factor (anti-VEGF) injections are the standard of care for diabetic macular edema (DME), a common complication of diabetes. This study aimed to identify factors influencing DME intravitreal anti-VEGF treatment outcomes in real-world practice.

METHODS

This was a multi-center retrospective observational study using medical chart review of participants receiving anti-VEGF injections for DME (N = 248). Demographic and clinical variables were assessed for association with best corrected visual acuity (BCVA) and central macular thickness (CMT) outcomes using regression models.

RESULTS

There was a significant improvement in BCVA (p < 0.001) and CMT (p < 0.001) after 12 months of treatment, although 21% of participants had decreased BCVA, and 41% had a < 10% CMT reduction at 12 months. Higher baseline BCVA (p = 0.022, OR=-0.024, 95% CI=-0.046,-0.004) and longer duration of diabetic retinopathy (p = 0.048, OR=-0.064, 95% CI=-0.129,-0.001) were negative predictors for BCVA response, whereas Aflibercept treatment (p = 0.017, OR = 1.107, 95% CI = 0.220,2.051) compared with other drugs and a positive "early functional response" (p < 0.001, OR=-1.393, 95% CI=-1.946,-0.857) were positive predictors. A higher baseline CMT (p < 0.001, OR = 0.019, 95% CI = 0.012,0.0261) and an "early anatomical response", (p < 0.001, OR=-1.677, 95% CI=-2.456, -0.943) were predictors for greater reduction in CMT. Overall, the variables could predict only 23% of BCVA and 52% of CMT response.

CONCLUSIONS

The study shows a significant proportion of DME patients do not respond to anti-VEGF therapy and identifies several clinical predictors for treatment outcomes.

TRIAL REGISTRATION

The study was approved through the Human Research Ethics Committee, University of Tasmania (approval number H0012902), and the Southern Adelaide Clinical Human Research Ethics Committee (approval number 86 - 067).

Emerging roles of oxyntomodulin-based glucagon-like peptide-1/glucagon co-agonist analogs in diabetes and obesity

Oxyntomodulin (OXM) is an endogenous peptide hormone secreted from the intestines following nutrient ingestion that activates both glucagon-like peptide-1 (GLP-1) and glucagon receptors. OXM is known to exert various effects, including improvement in glucose tolerance, promotion of energy expenditure, acceleration of liver lipolysis, inhibition of food intake, delay of gastric emptying, neuroprotection, and pain relief. The antidiabetic and antiobesity properties have led to the development of biologically active and enzymatically stable OXM-based analogs with proposed therapeutic promise for metabolic diseases. Structural modification of OXM was ongoing to enhance its potency and prolong half-life, and several GLP-1/glucagon dual receptor agonist-based therapies are being explored in clinical trials for the treatment of type 2 diabetes mellitus and its complications. In the present article, we provide a brief overview of the physiology of OXM, focusing on its structural-activity relationship and ongoing clinical development.

Progress in genetics of type 2 diabetes and diabetic complications

Type 2 diabetes results from a complex interaction between genetic and environmental factors. Precision medicine for type 2 diabetes using genetic data is expected to predict the risk of developing diabetes and complications and to predict the effects of medications and life-style intervention more accurately for individuals. Genome-wide association studies (GWAS) have been conducted in European and Asian populations and new genetic loci have been identified that modulate the risk of developing type 2 diabetes. Novel loci were discovered by GWAS in diabetic complications with increasing sample sizes. Large-scale genome-wide association analysis and polygenic risk scores using biobank information is making it possible to predict the development of type 2 diabetes. In the ADVANCE clinical trial of type 2 diabetes, a multi-polygenic risk score was useful to predict diabetic complications and their response to treatment. Proteomics and metabolomics studies have been conducted and have revealed the associations between type 2 diabetes and inflammatory signals and amino acid synthesis. Using multi-omics analysis, comprehensive molecular mechanisms have been elucidated to guide the development of targeted therapy for type 2 diabetes and diabetic complications.

Manual and Application-Based Carbohydrate Counting and Glycemic Control in Type 1 Diabetes Subjects: A Narrative Review

Type 1 diabetes (T1DM) is the most common chronic disease in young adults and children, which is treated with insulin, usually given as basal and boluses. Carbohydrate counting (CHOC) helps patients to determine the correct meal doses. The aim of this review is to study the effect of CHOC on glucose control, body weight, insulin dose and quality of life (QoL). The literature search was conducted using PubMed from January 2010 to October 2022. Studies included in this review are limited to randomized controlled studies involving an intervention group undergoing CHOC and a control group following the usual practice, measuring glycosylated hemoglobin (HbA1c) as a parameter of glucose control and involving only T1DM subjects. A total of ten articles were found to fulfill the criteria involving 1034 patients. Most of the studies showed a positive impact of CHOC on glucose control, especially in adults, where five out of six studies were statistically positive. However, in pediatrics, only two out of four showed a positive outcome. In all four studies using mobile applications, CHOC was better at controlling glucose. No difference was seen between the CHOC group and the control regarding the risk of severe hypoglycemia. In fact, two studies have shown lower hypoglycemia rates. No change in weight was observed in most of the studies (six out of eight). In subjects with T1DM, CHOC might provide better glucose control than traditional care without a significant increment in severe hypoglycemia or weight gain. Mobile application-based models showed promising results in glucose control.

An Overview towards Zebrafish Larvae as a Model for Ocular Diseases

Despite the obvious morphological differences in the visual system, zebrafish share a similar architecture and components of the same embryonic origin as humans. The zebrafish retina has the same layered structure and cell types with similar metabolic and phototransduction support as humans, and is functional 72 h after fertilization, allowing tests of visual function to be performed. The zebrafish genomic database supports genetic mapping studies as well as gene editing, both of which are useful in the ophthalmological field. It is possible to model ocular disorders in zebrafish, as well as inherited retinal diseases or congenital or acquired malformations. Several approaches allow the evaluation of local pathological processes derived from systemic disorders, such as chemical exposure to produce retinal hypoxia or glucose exposure to produce hyperglycemia, mimicking retinopathy of prematurity or diabetic retinopathy, respectively. The pathogenesis of ocular infections, autoimmune diseases, or aging can also be assessed in zebrafish larvae, and the preserved cellular and molecular immune mechanisms can be assessed. Finally, the zebrafish model for the study of the pathologies of the visual system complements certain deficiencies in experimental models of mammals since the regeneration of the zebrafish retina is a valuable tool for the study of degenerative processes and the discovery of new drugs and therapies.

The link between glycemic control measures and eye microvascular complications in a clinical cohort of type 2 diabetes with microRNA-223-3p signature

BACKGROUND

Type 2 diabetes (T2D) is a critical healthcare challenge and priority in Qatar which is listed amongst the top 10 countries in the world, with its prevalence presently at 17% double the global average. MicroRNAs (miRNAs) are implicated in the pathogenesis of (T2D) and long-term microvascular complications including diabetic retinopathy (DR).

METHODS

In this study, a T2D cohort that accurately matches the characteristics of the general population was employed to find microRNA (miRNA) signatures that are correlated with glycemic and β cell function measurements. Targeted miRNA profiling was performed in (471) T2D individuals with or without DR and (491) (non-diabetic) healthy controls from the Qatar Biobank. Discovery analysis identified 20 differentially expressed miRNAs in T2D compared to controls, of which miR-223-3p was significantly upregulated (fold change:5.16, p = 3.6e-02) and positively correlated with glucose and hemoglobin A1c (HbA1c) levels (p-value = 9.88e-04 and 1.64e-05, respectively), but did not show any significant associations with insulin or C-peptide. Accordingly, we performed functional validation using a miR-223-3p mimic (overexpression) under control and hyperglycemia-induced conditions in a zebrafish model.

RESULTS

Over-expression of miR-223-3p alone was associated with significantly higher glucose (42.7 mg/dL, n = 75 vs 38.7 mg/dL, n = 75, p = 0.02) and degenerated retinal vasculature, and altered retinal morphology involving changes in the ganglion cell layer and inner and outer nuclear layers. Assessment of retinal angiogenesis revealed significant upregulation in the expression of vascular endothelial growth factor and its receptors, including kinase insert domain receptor. Further, the pancreatic markers, pancreatic and duodenal homeobox 1, and the insulin gene expressions were upregulated in the miR-223-3p group.

CONCLUSION

Our zebrafish model validates a novel correlation between miR-223-3p and DR development. Targeting miR-223-3p in T2D patients may serve as a promising therapeutic strategy to control DR in at-risk individuals.