Treatment Diabetic Retinopathy Research Articles

Autophagy-dependent ferroptosis may play a critical role in early stages of diabetic retinopathy

Diabetic retinopathy (DR), as one of the most common and significant microvascular complications of diabetes mellitus (DM), continues to elude effective targeted treatment for vision loss despite ongoing enrichment of the under-standing of its pathogenic mechanisms from perspectives such as inflammation and oxidative stress. Recent studies have indicated that characteristic neuroglial degeneration induced by DM occurs before the onset of apparent microvascular lesions. In order to comprehensively grasp the early-stage pathological changes of DR, the retinal neurovascular unit (NVU) will become a crucial focal point for future research into the occurrence and progression of DR. Based on existing evidence, ferroptosis, a form of cell death regulated by processes like ferritinophagy and chaperone-mediated autophagy, mediates apoptosis in retinal NVU components, including pericytes and ganglion cells. Autophagy-dependent ferroptosis-related factors, including BECN1 and FABP4, may serve as both biomarkers for DR occurrence and development and potentially crucial targets for future effective DR treatments. The aforementioned findings present novel perspectives for comprehending the mechanisms underlying the early-stage pathological alterations in DR and open up innovative avenues for investigating supplementary therapeutic strategies.

ANTI-VEGF THERAPY FOR DIABETIC RETINOPATHY

Diabetic retinopathy is one of the most severe complications of diabetes mellitus, requiring the participation of doctors of various specialties: endocrinologists, diabetologists, therapists, cardiologists, surgeons, anesthesiologists and others.The task of an ophthalmologist is to identify pathological changes in the eye associated with diabetes mellitus and prescribe appropriate treatment.There are three main methods for treating diabetic retinopathy: laser coagulation of the retina;intravitreal injections of anti-VEGF and glucocorticoids;vitreoretinal surgery.This literature review examines the use of vascular endothelial growth factor inhibitors in the treatment of diabetic retinopathy. In particular, it discusses the most relevant drugs, the most important studies on the therapy of DR and diabetic macular edema, as well as a post hoc analysis of these studies. In addition, the role of these drugs in the therapy of refractory DME is discussed.

Preparation and Characterization of Ozonated Liposomes Loaded with Curcumin: A Potential Approach for Diabetic Retinopathy Treatment

Background: Limitations in drug penetration are overcome by nanotechnology, particularly liposomes, which enhance targeted administration of ocular medications. Liposomes can augment the therapeutic effects of curcumin, a natural compound with positive impacts on the retina. Treatments for eye diseases can also benefit from the antibacterial properties of ozonated oil liposomes. Objectives: This study aims to develop and evaluate ozonated liposomes loaded with curcumin for ocular drug delivery applications, specifically targeting diabetic retinopathy (DR). Methods: Liposomal nanoparticles were prepared using thin-film hydration, incorporating phospholipids, lecithin, cholesterol, ozonated oil, and curcumin. We assessed physicochemical properties including particle size, zeta potential, encapsulation efficiency (EE), and morphology. Drug release profiles and stability studies were also conducted. Results: The optimized liposomes showed a particle size of 84.77 nm, a zeta potential of -16.8 mV, and an EE of 94.73%. The formulation exhibited sustained curcumin release over 24 hours, reaching 82.09% cumulative release. Stability studies indicated minimal changes in key parameters over three months at room temperature. Conclusions: The developed ozonated liposomal formulation demonstrates promising characteristics for curcumin delivery, potentially enhancing its therapeutic efficacy in ocular applications, particularly for DR.

Paeoniflorin-mediated downregulation of VEGFA: unveiling the therapeutic mechanism of buyang huanwu decoction in diabetic retinopathy.

Diabetic retinopathy (DR) is a leading cause of blindness globally. Buyang Huanwu decoction (BHD) is a traditional Chinese medicine for treating DR, but its therapeutic mechanisms are not fully understood. This study aimed to elucidate and validate the underlying mechanisms of BHD in DR treatment through network pharmacology and in vitro experiments. We identified active compounds in BHD and their associated targets using the TCMSP and SwissTargetPrediction. DR-related targets were sourced from GeneCards, NCBI, and OMIM databases. The protein-protein interaction (PPI) network and enrichment analyses were employed to predict common targets and pathways. Subsequent molecular docking and in vitro experiments, including cell viability assays, RT-qPCR, flow cytometry, and Western blot, were conducted to validate the anti-DR mechanism of BHD. Network pharmacology identified paeoniflorin as a key active compound in BHD for treating DR, with VEGFA emerging as a central target. Molecular docking suggested a strong binding affinity between paeoniflorin and VEGFA. In vitro experiments confirmed that paeoniflorin attenuated high glucose-induced increases in cell viability, migration, apoptosis, and inflammatory cytokine expression in retinal pigment epithelial cells. The therapeutic effect of paeoniflorin was primarily mediated through the downregulation of VEGFA expression. Our study demonstrates that paeoniflorin, a key active compound in BHD, effectively mitigates DR by downregulating VEGFA expression and reducing high glucose-induced cellular alterations, thereby highlighting its potential as a therapeutic agent for DR.

Patient and Physician Perspectives of Diabetic Retinopathy and Diabetic Macular Edema Diagnosis, Treatment and Progression: A Podcast Article.

Diabetic retinopathy (DR) is one of the leading causes of vision loss among people of working age. However, people with diabetes are often unaware of the importance of DR screening for preserving vision, highlighting the importance of patient education about DR and DR-related ocular and systemic comorbidities. In this podcast, three patients with different stages of DR and two ophthalmologists exchanged their views on diagnosis, treatment, and progression of DR and diabetic macular edema. The discussion revealed that DR affects not only the physical aspects of patients' lives but also their mental wellbeing. The challenges of a DR diagnosis can be compounded by communication gaps that exist between patients, physicians, and the pharmaceutical industry. Development of new therapies is currently informed mainly by physician perspectives. However, the large burden of current treatments calls for new therapeutic approaches that meet patients' needs better. The preferred method of treatment administration can differ from patient to patient and the choices between treatments that necessitate repeated visits, monitoring, and at-home care must be discussed. As such, going forward it is crucial to consider both the physician and patient perspectives in shaping the clinical landscape of DR.

Obtusin ameliorates diabetic retinopathy by inhibiting oxidative stress and inflammation.

Diabetic retinopathy (DR) is linked to an increased risk of psychiatric and neurological conditions, largely due to chronic inflammation, oxidative stress, and microvascular damage associated with the disease. Emerging evidence suggests that Cassia seed extract has significant anti-inflammatory and antioxidant properties. However, the therapeutic potential of obtusin, a major compound in Cassia seed, and its underlying mechanisms remain unclear. This study aimed to evaluate the therapeutic efficacy of obtusin in the treatment of DR. Db/db mice were treated with obtusin (5 and 10mg/kg/day) for 12 weeks. Throughout the study, body weight, blood glucose levels, and lipid profiles were monitored. Retinal histopathology and transmission electron microscopy were used to assess the pharmacological effects of obtusin in vivo. Additionally, in vitro assays were conducted on human retinal microvascular endothelial cells cultured under high glucose conditions to explore obtusin's potential role in mitigating DR. Obtusin treatment in diabetic mice significantly reduced blood glucose levels, improved dyslipidemia, thickened retinal layers, reduced retinal oxidative stress, and inhibited the upregulation of inflammatory cytokines. It also lessened fundus microangiopathy and preserved the retina's normal barrier function. Mechanistic in vitro analysis suggested that obtusin targets the Poldip2-Nox4 oxidative stress axis and the NF-κB-MAPK-VEGFA inflammatory pathway, both of which are implicated in DR. Our findings suggest that the Poldip2-Nox4 oxidative stress axis and the NF-κB-MAPK-VEGFA inflammatory pathway could be therapeutic targets for obtusin in the treatment of DR and its associated psychiatric and neurological conditions.

Detection of Diabetic Retinopathy Using VGG19 and ResNet 50 Models

Diabetic Retinopathy (DR) is an ocular condition that can manifest in individuals living with Diabetes Mellitus (DM). Retinal fundus examinations must be conducted on DM individuals as early identification and treatment of DR can reduce the risk of impaired vision or blindness. The manual diagnosis of DR conducted by eye-care professionals can be tedious and time-consuming, especially during mass screenings. Deep learning (DL) techniques are being used to provide automated diagnosis of DR. This study adopted two CNN (VGG 19 and ResNet50) models for the binary classification of DR (Non-referable DR and Referable DR). Both models were trained and validated with retinal fundus images from publicly available datasets. After training with Kaggle dataset, VGG 19 and ResNet50 models achieved accuracies of 94.3% and 96.9% respectively. For external validation, varying levels of accuracy, sensitivity and specificity were obtained for the two models on different datasets. The sensitivity of the VGG 19 model for the Messidor 2 dataset was 78.8% while the sensitivity of the ResNet50 model for the Indian Diabetic Retinopathy Image Dataset (IDRiD) was 85.7%. Findings in this study have shown that DR detection with deep learning techniques can serve as an assistive tool for eye-care professionals in the future.

Development of puerarin-loaded poly(lactic acid) microspheres for sustained ocular delivery: In vitro/vivo evaluation

Diabetic retinopathy, an ocular complication of diabetes, is an important cause of blindness in adults. Puerarin is considered to have promising potential for clinical use in treating diabetic retinopathy. In this study, we designed a novel puerarin-loaded poly(lactic acid) sustained-release microspheres suitable for ocular administration, and we assessed itsin vitro and in vivo properties. The preparation of puerarin-loaded microspheres was optimized by Box-Behnken response surface design. The encapsulation efficiency and drug loading of microspheres were 35.71% and 3.85%, respectively. The microspheres exhibited good dispersion and high safety, making it suitable for ocular drug delivery. In vitro release demonstrated that microspheres had a well-sustained release effectiveness, and its release behavior complied with the zero-order kinetic characteristics. The results of ocular tissue distribution revealed that the CmaxandAUC0-∞ of the microspheres group in the retina and choroid were considerably higher than those of the solution group and the intravenous injection group. This research revealed that intravitreal injection of microspheres can significantly prolong the half-life of puerarin in eye tissues and achieve sustained drug release. Therefore, intravitreal injection of microspheres has positive implications for the treatment of diabetic retinopathy.

The application of artificial intelligence in diabetic retinopathy: progress and prospects.

In recent years, artificial intelligence (AI), especially deep learning models, has increasingly been integrated into diagnosing and treating diabetic retinopathy (DR). From delving into the singular realm of ocular fundus photography to the gradual development of proteomics and other molecular approaches, from machine learning (ML) to deep learning (DL), the journey has seen a transition from a binary diagnosis of "presence or absence" to the capability of discerning the progression and severity of DR based on images from various stages of the disease course. Since the FDA approval of IDx-DR in 2018, a plethora of AI models has mushroomed, gradually gaining recognition through a myriad of clinical trials and validations. AI has greatly improved early DR detection, and we're nearing the use of AI in telemedicine to tackle medical resource shortages and health inequities in various areas. This comprehensive review meticulously analyzes the literature and clinical trials of recent years, highlighting key AI models for DR diagnosis and treatment, including their theoretical bases, features, applicability, and addressing current challenges like bias, transparency, and ethics. It also presents a prospective outlook on the future development in this domain.

Structurally Minimalized and Druglike TGase2 Inhibitors Based on 7-Aminoquinoline-5,8-dione Scaffolds for the Treatment of Diabetic Retinopathy.

Diabetic retinopathy is a disease that can cause vision loss leading to blindness in people with diabetes. Improved methods to treat and prevent vision loss in diabetic patients are in high demand owing to limited current treatment procedures. Herein, we report a new class of transglutaminase 2 (TGase2) inhibitors for the treatment of diabetic retinopathy based on 7-aminoquinoline-5,8-dione derivatives. 7-Amino-2-phenylquinoline-5,8-dione 11 and 7-amino-2-{4-[(1-methylpiperidin-4-yl)oxy]phenyl}quinoline-5,8-dione 23 exhibited potent inhibitory activities against TGase2 in a fibrinogen array-based on-chip TGase2 activity assay and in an in situ assay in human retinal microvascular endothelial cells, with IC50 values of 5.88 and 1.12 μM in vitro, and 0.09 and 0.07 μM in situ, respectively. Pharmacokinetically favorable 7-amino-2-{4-[(1-isopropylpiperidin-4-yl)oxy] phenyl}quinoline-5,8-dione 22 inhibited vascular leakage in the retinas of streptozotocin-induced diabetic mice via oral administration. Results from the AL5 kinetic assay and a molecular docking study suggest that the inhibitors may bind to TGase2 remote from the active site.

Molecular Docking and In Silico ADME(T) Evaluation of Selective Phytochemical Inhibitors of VEGF2 Target for the Treatment of Diabetic Retinopathy

Molecular Docking and In Silico ADME(T) Evaluation of Selective Phytochemical Inhibitors of VEGF2 Target for the Treatment of Diabetic Retinopathy

Interleukin-1 receptor-dependent and -independent caspase-1 activity in retinal cells mediated by receptor interacting protein 2.

Inflammation and cell death play an important role in the pathogenesis of diabetic retinopathy. Previously we observed sustained activation of pro-inflammatory caspase-1 in retinas of diabetic animals and patients. In this study, we aimed to look at mechanisms underlying chronic caspase-1 activation in vitro and in vivo. Non-diabetic and diabetic wild type and IL-1 receptor (IL-1R1) knockout mice were used for in vivo experiments. Diabetes was induced using STZ (streptozotocin). Human Müller cells were used for in vitro studies. Cells were treated with either 5mM or 25mM glucose or interleukin-1beta (IL-1β) in the presence or absence of IL-1 receptor antagonist (IL-1ra) or siRNA against RIP2 (receptor interacting protein-2) for up to 96h. Outcome measurements to assess Müller cell functions included measurements of caspase-1 activity using a fluorescence peptide substrate, production of IL-1β by Elisa, and cell death using trypan blue exclusion assays. Our in vivo results demonstrate that caspase-1 activation progresses from an IL-1R1 independent mechanism at 10weeks of diabetes to an IL-1R1 dependent mechanism at 20weeks indicating that feedback through IL-1R1 is crucial for sustained caspase-1 activity in retinas of mice. A similar hyperglycemia-mediated caspase-1/IL-1β/IL-1R1 feedback signaling was detected in vitro in human Müller cells which was prevented by treatment with IL-1ra. Our data also indicate that hyperglycemia induces caspase-1 activation initially but IL-1β sustains caspase-1 activation via caspase-1/IL-1β/IL-1R1 feedback and we identified RIP2 as mediator for both hyperglycemia- and IL-1β-induced caspase-1 activation. Activation of caspase-1/IL-1β/IL-1R1 feedback signaling caused Müller cell death which was prevented by RIP2 knockdown. We conclude that any intervention in caspase-1/IL-1β/IL-1R1 feedback signaling presents novel therapeutic options for the treatment of diabetic retinopathy.

Poly (ADP-Ribose) Polymerase-1 (PARP-1) Inhibitors in Diabetic Retinopathy: An Attractive but Elusive Choice for Drug Development.

Owing to its promiscuous roles, poly (ADP-ribose) polymerase-1 (PARP-1) is involved in various neurological disorders including several retinal pathologies. Diabetic retinopathy (DR) is the most common microvascular complication of diabetes mellitus affecting the retina. In the present review, we highlight the importance of PARP-1 participation in pathophysiology of DR and discuss promising potential inhibitors for treatment. A high glucose level enhances PARP-1 expression; PARP inhibitors have gained attention due to their potential therapeutic effects in DR. They target different checkpoints (blocking nuclear transcription factor (NF-κB) activation; oxidative stress protection, influence on vascular endothelial growth factor (VEGF) expression, impacting neovascularization). Nowadays, there are several improved clinical PARP-1 inhibitors with different allosteric effects. Combining PARP-1 inhibitors with other compounds is another promising option in DR treatments. Besides pharmacological inhibition, genetic disruption of the PARP-1 gene is another approach in PARP-1-initiated therapies. In terms of future treatments, the limitations of single-target approaches shift the focus onto combined therapies. We emphasize the importance of multi-targeted therapies, which could be effective not only in DR, but also in other ischemic conditions.

Predicting vision-threatening diabetic retinopathy in patients with type 2 diabetes mellitus: Systematic review, meta-analysis, and prospective validation study.

Delayed diagnosis and treatment of vision-threatening diabetic retinopathy (VTDR) is a common cause of visual impairment in individuals with type 2 diabetes mellitus (T2DM). Identification of VTDR predictors is the key to early prevention and intervention, but the predictors from previous studies are inconsistent. This study aims to conduct a systematic review and meta-analysis of the existing evidence for VTDR predictors, then to develop a risk prediction model after quantitatively summarising the predictors across studies, and finally to validate the model with two Chinese cohorts. We systematically retrieved cohort studies that reported predictors of VTDR in T2DM patients from PubMed, Ovid, Embase, Scopus, Cochrane Library, Web of Science, and ProQuest from their inception to December 2023. We extracted predictors reported in two or more studies and combined their corresponding relative risk (RRs) using meta-analysis to obtain pooled RRs. We only selected predictors with statistically significant pooled RRs to develop the prediction model. We also prospectively collected two Chinese cohorts of T2DM patients as the validation set and assessed the discrimination and calibration performance of the prediction model by the time-dependent ROC curve and calibration curve. Twenty-one cohort studies involving 622 490 patients with T2DM and 57 107 patients with VTDR were included in the meta-analysis. Age of diabetes onset, duration of diabetes, glycosylated haemoglobin (HbA1c), estimated glomerular filtration rate (eGFR), hypertension, high albuminuria and diabetic treatment were used to construct the prediction model. We validated the model externally in a prospective multicentre cohort of 555 patients with a median follow-up of 52 months (interquartile range = 39-77). The area under the curve (AUC) of the prediction model was all above 0.8 for 3- to 10-year follow-up periods and different cut-off value of each year provided the optimal balance between sensitivity and specificity. The data points of the calibration curves for each year closely surround the corresponding dashed line. The risk prediction model of VTDR has high discrimination and calibration performance based on validation cohorts. Given its demonstrated effectiveness, there is significant potential to expand the utilisation of this model within clinical settings to enhance the detection and management of individuals at high risk of VTDR.

Diabetic Retinopathy Image Lesion Segmentation with Feature Fusion Relation Transformer Network

Diabetes is a common disease that affects different vital organs of the human body, including the eyes. In diabetic patients, a change in blood sugar level leads to eye problems. Around 80% of the patients who have diabetes for more than 10 years have severe eye-related pathological disorders such as retinopathy and maculopathy. Proper detection, diagnosis, and treatment of eye-related pathologies prevent damage to the eye during the earliest stages of diabetic disease—the developed stage findings in patients losing their vision. The retinal damage due to diabetes is termed Diabetic Retinopathy (DR). The treatment of DR involves detecting the presence of the disease in the form of microaneurysms (MA), hemorrhages (HE), and exudates (EX) in the retinal area. The process of segmenting a massive segment of Retinal Images (RI) performs a prominent role in DR classification. The existing research concentrates on Optic Disc (OD) segmentation. This article focuses on the segmentation of MA, HE, and EX using a Feature Fusion Relation Transformer Network (FFRTNet). In this research, the benchmark dataset, the Indian Diabetic Retinopathy Image Dataset (IDRID), is used for the ablation study to evaluate the use of every module. The proposed method, FFRTNet, is compared with state-of-the-art methods. The evaluation of FFRTNet enhances the segmentation by 3.56%, 4.34%, and 3.75% on metrics, namely sensitivity, Intersection-over-Union (IoU), and Dice coefficient (DICE). The qualitative and quantitative results proved the superiority of FFRTNet in segmenting lesions in DR.

Development and Novel Therapeutics in Diabetic Retinopathy.

Diabetic retinopathy (DR) is a complication of diabetes mellitus which causes retinal damage which when left untreated will cause visual problems. As the prevalence of DR increases over the years, there is a need to optimise the currently available treatments as well as developing novel drugs to improve the therapy provided for the patients in the clinical practice. Several pharmacological therapies like, anti-vascular endothelial growth factor and anti-inflammatory therapies which include intravitreal, and implant of corticosteroids are significant in the management to decrease the risk of DR-related vision impairment. Clinical trials for novel drug therapies are still ongoing till this day to enhance the efficacy of DR treatment. Even though there are also modern treatments such as laser therapy for the patients, prevention should be done to lower the number of individuals affected by DR. Due to the complexity of DR, there are numerous obstacles to develop new medications for DR which include the increasing healthcare cost of DR treatment. New insights such as utilisation of artificial intelligence will be implemented into the management of DR as it has proved its potential in aiding the screening process. In parallel with the increase in DR prevalence and the number of treatments developed, extensive understanding of the mechanism of action of DR should be further improved to prevent more complications in the future. This review summarises the epidemiological trend, prevention strategies, challenges in treatment, current novel therapeutics (including drugs under clinical trials), future therapeutic trends and possibilities for implementing AI in the early diagnosis and management of DR.

Neuritin alleviates Diabetic Retinopathy by Regulating Endoplasmic Reticulum Stress in Rats.

Neuritin, a small-molecule neurotrophic factor, maintains neuronal cell activity, inhibits apoptosis, promotes process growth, and regulates neural progenitor cell differentiation, migration, and synaptic maturation. Neuritin helps retinal ganglion cells (RGCs) survive optic nerve injury in rats and regenerate axons. However, the role of Neuritin in Diabetic retinopathy (DR) is unclear. This study is intended to investigate the effect and mechanism of Neuritin in DR. For this purpose, we established DR rat models and injected Neuritin into them. This study provides a potential treatment for diabetic retinopathy. The rat model of DR was established by streptozotocin (STZ) injection, and the effect of Neuritin on DR was detected by intravitreal injection. Histological analysis was performed by H&E and TUNEL methods. The mRNA and protein expressions of endoplasmic reticulum stress (ERS) pathway-related transcription factors were detected by qRT-PCR and western blot. The blood-retinal barrier (BRB) function was assessed using the patch-clamp technique and Evans blue leakage assay. Neuritin significantly improved the retinal structure, restrained the apoptosis of retinal cells, and protected the normal function of BRB in DR model rats. Mechanistically, Neuritin may function by inhibiting the expression of GRP78, ASK1, Caspase-12, VEGF, and so on. Our results indicate that Neuritin alleviates retinal damage in DR rats via the inactive endoplasmic reticulum pathway. Our study provides a potential treatment for DR.

Prevalence and Risk Factors of Diabetic Retinopathy among Type 2 Diabetic Patients in Tertiary Care Hospital of Gandaki Province of Nepal

Background Diabetic retinopathy (DR) is one of the commonest causes of blindness in Nepal. This study aimed to determine the prevalence and risk factors of diabetic retinopathy in type 2 diabetic patients in a tertiary care hospital of Gandaki Province of Nepal. Methods This was a hospital based cross-sectional study conducted among 162 patients of type 2 diabetes aged 30 years and above. Standard proforma was used to collect socio-demographic and clinical variables of the patients. Detailed eye examination including fundus evaluation under mydriasis was done on all patients and diabetic retinopathy was classified according to Early Treatment of Diabetic Retinopathy Study Classification. Results The mean ±SD of age of the study sample was 61.99 ±11.69 years. The prevalence of diabetic retinopathy was 41.98%. Among the patients with diabetic retinopathy, the prevalence of mild NPDR, moderate NPDR, severe NPDR, very severe NPDR and PDR were 51.47%, 25%, 11.76%, 1.47%, and 10.29% respectively. There was statistically significant association of diabetic retinopathy with duration of diabetes and chronic kidney disease. However, there was no statistically significant association of diabetic retinopathy with gender, family history, hypertension, history of smoking, history of alcohol, treatment history and physical activity. Conclusions There is high prevalence of diabetic retinopathy among the diabetic patients. Longer duration of diabetes and chronic kidney disease were the significant risk factors for diabetic retinopathy. Early diagnosis and treatment of diabetic retinopathy is essential to reduce blindness in diabetic patients.

Therapeutic potential of histamine H4 receptor antagonist as a preventive treatment for diabetic retinopathy in mice

Diabetic retinopathy (DR) is a prevalent complication of diabetes, often resulting in vision loss and blindness. Existing treatments primarily aim to control blood sugar levels and inhibit angiogenesis. However, current therapies for DR, such as anti-VEGF and laser photocoagulation, are frequently invasive, and can cause adverse side effects. Consequently, there is a critical need for new preventive therapeutics to address DR more effectively. This study aimed to examine the therapeutic potential of a histamine H4 receptor (HRH4) antagonist as a preventive treatment for DR in mice. A mouse model of DR was established by intraperitoneally injecting 200 mg/kg of streptozotocin (STZ). Immune cell infiltration into the retina of mice with STZ-induced diabetes was measured using fluorescence-activated cell sorting (FACS) 12 weeks after STZ injection. The preventive effects of the HRH4 antagonist on inflammation and pathological retinal vessel leakage were determined in a mouse model of DR. Infiltration of HRH4-expressing macrophages increased in the retina of mice with STZ-induced DR. The HRH4 antagonist prevented macrophage infiltration and retinal vascular leakage to prevent STZ-induced DR in mice without causing any retinal toxicity. The infiltration of macrophages increased in the retina of mice with STZ-induced diabetes through HRH4, indicating that HRH4 is potentially a novel preventative therapeutic target in DR. These findings suggest that targeting HRH4 is a promising strategy for the prevention and treatment of DR.

Crosstalk between MIR-96 and IRS/PI3K/AKT/VEGF cascade in hRPE cells; A potential target for preventing diabetic retinopathy.

Regulation of visual system function demands precise gene regulation. Dysregulation of miRNAs, as key regulators of gene expression in retinal cells, contributes to different eye disorders such as diabetic retinopathy (DR), macular edema, and glaucoma. MIR-96, a member of the MIR-183 cluster family, is widely expressed in the retina, and its alteration is associated with neovascular eye diseases. MIR-96 regulates protein cascades in inflammatory and insulin signaling pathways, but further investigation is required to understand its potential effects on related genes. For this purpose, we identified a series of key target genes for MIR-96 based on gene and protein interaction networks and utilized text-mining resources. To examine the MIR-96 impact on candidate gene expression, we overexpressed MIR-96 via adeno-associated virus (AAV)-based plasmids in human retinal pigment epithelial (RPE) cells. Based on Real-Time PCR results, the relative expression of the selected genes responded differently to overexpressed MIR-96. While the expression levels of IRS2, FOXO1, and ERK2 (MAPK1) were significantly decreased, the SERPINF1 gene exhibited high expression simultaneously. pAAV-delivered MIR-96 had no adverse effect on the viability of human RPE cells. The data showed that changes in insulin receptor substrate-2 (IRS2) expression play a role in disrupted retinal insulin signaling and contribute to the development of diabetic complications. Considered collectively, our findings suggest that altered MIR-96 and its impact on IRS/PI3K/AKT/VEGF axis regulation contribute to DR progression. Therefore, further investigation of the IRS/PI3K/AKT/VEGF axis is recommended as a potential target for DR treatment.