Role of Inflammation in Diabetic Retinopathy

METTL3/YTHDC1 mediates up-regulation of lncRNA OGRU in an m6A-dependent manner involving in oxidative stress and inflammation of HG-induced Müller cells

BACKGROUND

Diabetic retinopathy (DR) is a common complication of diabetes, which may cause visual disturbance and even loss of sight. Oxidative stress and inflammation are two crucial pathological factors of DR; however, their specific regulatory mechanisms in DR remain obscure.

METHODS

DR models were established in streptozotocin-challenged rats and high glucose (HG)-stimulated Müller cells. Western blotting and RT-qPCR were performed to determine target molecule levels. ROS release was evaluated by DCFH-DA staining, and the levels of MDA, GSH, SOD, and CAT were detected using commercial kits. The levels of proinflammatory factors (TNF-α, IL-1β, IL-6, MCP-1, and CXCL-1) were analyzed by RT-qPCR and ELISA. The subcellular localization of OGRU was observed by FISH. Molecular interaction was evaluated by RIP. M6A level was assessed by MeRIP and colorimetric quantification kit.

RESULTS

HG stimulation or diabetic stress resulted in an elevation in the overall m6A level, as well as expression level of methyltransferase-like 3 (METTL3) in the experimental models of DR. M6A writer METTL3 stabilized lncRNA OGRU via m6A modification. Functionally, METTL3 deficiency relieved HG-induced oxidative stress damage and inflammation in Müller cells. Rescue assays demonstrated that OGRU overexpression reversed METTL3 silencing-mediated protection against HG-stimulated Müller cells. Furthermore, YTH Domain-Containing Protein 1 (YTHDC1) coordinated with METTL3 to enhance OGRU stability in an m6A-dependent manner.

CONCLUSION

METTL3-mediated m6A modification stabilized OGRU with assistance of YTHDC1, which led to oxidative stress and inflammation during DR progression. Targeting METTL3/YTHDC1/OGRU axis might be a potential therapeutic strategy for DR.

Impact of Selective Peroxisome Proliferator-Activated Receptor (PPAR)-α Modulators and Fibrates on Microvascular Disease: Is There Still Room?

PURPOSE OF REVIEW

This review examines the role of fibrates and the selective PPAR-alpha modulators (SPPARM-α), pemafibrate, in diabetic microvascular disease. It reviews their potential to mitigate residual risk in retinopathy, nephropathy, neuropathy and peripheral vascular disease.

RECENT FINDINGS

These pharmacotherapies, beyond their lipid-lowering effects, may exert anti-inflammatory, antioxidant, and endothelial-protective actions. Secondary analyses of large clinical trials supports their efficacy in slowing retinopathy progression, reducing albuminuria, and preventing minor amputations. Recent analyses suggest that pemafibrate offers an enhanced efficacy and safety profile compared to conventional fibrate and may lower the incidence of diabetic foot ulcers and gangrene. Fibrates and SPPARM-α agonists represent promising therapies to prevent diabetic microvascular complications. Their benefits in reducing microvascular damage support their broader adoption in clinical practice. However, additional dedicated randomized trials are essential to validate the efficacy of those agents in contemporary diabetes care era and to address the growing burden of diabetes-related microvascular complications.

CircTHADA regulates endothelial cell pyroptosis in diabetic retinopathy through miR-494-3p/CASP1/GSDMD-N/IL-1β pathway

Our study aimed to elucidate the mechanism by which circTHADA competitively adsorbs miR-494-3p to regulate CASP1-mediated endothelial cell (EC) pyroptosis in diabetic retinopathy (DR). To be specific, we used high glucose (HG)-induced human retinal microvascular endothelial cells (HRMECs) as DR cell models and streptozotocin (STZ)-treated mice as DR mouse models. The expression levels of circTHADA, miR-494-3p, CASP1, NLRP3, GSDMD-N and IL-1β were detected and flow cytrometry was applied to measure cell pyroptosis rate and dual luciferase reporter assays were utilized to determine the direct binding sites. As a result, exacerbated EC pyroptosis in DR was detected in DR cell and mouse models. Based on differentially expressed circRNA profiles by microarray and experimental verification, circTHADA was filtered and identified to regulate CASP1-mediated EC pyroptosis. miR-494-3p was then proven to be involved in circTHADA-mediated ceRNA network by bioinformatics analysis and experimental verification. Further gain- and loss-of-function experiments and rescue experiments revealed the function of the circTHADA/miR-494-3p/CASP1 axis in pyroptosis.

Role of Tau Protein Hyperphosphorylation in Diabetic Retinal Neurodegeneration

Diabetic retinal neurodegeneration (DRN) is an early manifestation of diabetic retinopathy (DR) characterized by neurodegeneration that precedes microvascular abnormalities in the retina. DRN is characterized by apoptosis of retinal ganglion cells (involves alterations in retinal ganglion cells [RGCs], photoreceptors, amacrine cells and bipolar cells and so on), reactive gliosis, and reduced retinal neuronal function. Tau, a microtubule-associated protein, is a key mediator of neurotoxicity in neurodegenerative diseases, with functions in phosphorylation-dependent microtubule assembly and stabilization, axonal transport, and neurite outgrowth. The hyperphosphorylated tau (p-tau) loses its ability to bind to microtubules and aggregates to form paired helical filaments (PHFs), which further form neurofibrillary tangles (NFTs), leading to abnormal cell scaffolding and cell death. Studies have shown that p-tau can cause degeneration of RGCs in DR, making tau pathology a new pathophysiological model for DR. Here, we review the mechanisms by which p-tau contribute to DRN, including insulin resistance or lack of insulin, mitochondrial damage such as mitophagy impairment, mitochondrial axonal transport defects, mitochondrial bioenergetics dysfunction, and impaired mitochondrial dynamics, Abeta toxicity, and inflammation. Therefore, this article proposes that tau protein hyperphosphorylation plays a crucial role in the pathogenesis of DRN and may serve as a novel therapeutic target for combating DRN.

Functional diabetic retinopathy: A new concept to improve management of diabetic retinal diseases

Multifocal functional tests are not routinely performed in diabetic retinopathy (DR) and diabetic macular edema (DME) management. We emphasise their importance and coin the term functional diabetic retinopathy (FDR). We reviewed current guidelines on management of DR/DME, and literature on diabetic retinal neurodegeneration (DRN) and functional deficits in DR/DME. Functional visual loss due to DRN precedes vasculopathy and clinical DR; however, currently the diagnosis and management of DR/DME are based on classical signs of retinal vasculopathy and structural changes shown by funduscopy, fundus photographs, and optical coherence tomography (OCT). Furthermore, DME can mask DRN-based retinal layer thinning by OCT and is focussed on the macular region. The only functional test recommended in national and international guidelines on DR/DME is best-corrected visual acuity, a test of foveal function (<1 % of retina). Multifocal functional tests can objectively characterize both foveal and extrafoveal, localized and global, function. Current recommendations for DR/DME screening are inadequate to detect FDR affecting the greater retina. Early detection of FDR using multifocal functional tests could bring DR/DME management strategies forward enabling prevention of the later stage vision-threatening complications. After all, the end point of patient care is functional outcomes.

The Role of Diet and Oral Supplementation for the Management of Diabetic Retinopathy and Diabetic Macular Edema: A Narrative Review

Globally, diabetic retinopathy (DR) and diabetic macular edema (DME) are the leading causes of visual loss in working people. Current treatment approaches mostly target proliferative DR and DME, such as intravitreal injections of antivascular endothelial growth factor agents and laser photocoagulation. Before DR progresses into the more severe, sight-threatening proliferative stage, patients with early stages of the disease must get early and appropriate care. It has been suggested that nutraceuticals, which are natural functional foods with minimal adverse effects, may help diabetic patients with DR and DME. Several in vitro and in vivo studies were carried out over the last years, showing the potential benefits of several nutraceuticals in DR due to their neuroprotective, vasoprotective, anti-inflammatory, and antioxidant properties. Although most of the research is restricted to animal models and many nutraceuticals have low bioavailability, these compounds may adjuvate and implement conventional DR therapies. The purpose of this review is (i) to summarize the complex pathophysiology underlying DR and DME and (ii) to examine the main natural-derived molecules and dietary habits that can assist conventional therapies for the clinical management of DR and DME.

Tissue origin of endothelial cells determines immune system modulation and regulation of HIF-1α-, TGF-β-, and VEGF signaling

Tight junctions of vascular endothelial cells in the central nervous system form the blood-brain and inner blood-retinal barriers, the integrity of which are further influenced by neighboring cells such as pericytes, astrocytes/Müller glial processes, and immune cells. In addition, the retina is shielded from the fenestrated endothelium of the choriocapillaris by the epithelial barrier of the retinal pigment epithelium. Dysfunction of the blood retinal barriers and/or proliferation of retinal and choroidal endothelial cells are caused by late stages of diabetic retinopathy (DR) and neovascular age-related macular degeneration (nAMD), the main causes of blindness in western countries. To elucidate endothelial-derived pathomechanisms in DR and nAMD, we established immortalized mouse cell lines of retinal and choroidal endothelial cells and immortalized brain endothelial cells as CNS-derived controls. We then used immunofluorescence staining, state-of-the-art long-range RNA sequencing and monolayer permeability assays to compare the functional state of these cells depending on their tissue origin. We furthermore demonstrate that activation of the wingless-type MMTV integration site (Wnt)/β-catenin signaling pathway restored blood brain/retinal barrier properties in brain and retinal endothelial cells, but unexpectedly increased permeability of choroidal endothelial cells. Transcriptome profiling showed that depending on the tissue origin of endothelial cells, regulation of the immune system was altered and pathways such as hypoxia-inducible factor (HIF)-1/2α, transforming growth factor (TGF)-β, and vascular endothelial growth factor (VEGF) were differentially regulated, strongly indicating their contribution in the molecular pathogenesis of DR and nAMD. These findings significantly increase the understanding of the vascular biology of endothelial cells, highlighting the fact that depending on their tissue origin, their contribution to vascular pathologies varies.

Combination of Saffron (Crocus sativus), Elderberry (Sambucus nigra L.) and Melilotus officinalis Protects ARPE-19 Cells from Oxidative Stress

Oxidative stress is considered a common underlying mechanism in many retinal degenerative diseases and is often associated with inflammation. The use of dietary supplements containing Saffron has beneficial effects in ocular diseases, though the molecular mechanisms are still unclear. In this study, we investigated how Saffron can exert protective effects against oxidative damage in retinal pigment epithelial cells (ARPE-19) and whether its combination with Elderberry and Melilotus may have additive beneficial effects. ARPE-19 cells were pretreated with Saffron alone or in a mix containing Saffron, Elderberry and Melilotus, then exposed to hydrogen peroxide (H2O2) for 3 h. Afterwards, we evaluated cell viability, oxidative stress and inflammatory status. Our results showed that H2O2 reduced cell viability and total glutathione levels, while increasing caspase-3, caspase-1 and LDH activity. Moreover, H2O2 triggered ROS production, glutathione oxidation and IL-1β secretion. Pretreatments with Saffron alone or with the mix counteract these damaging effects by improving cell viability, reducing oxidative stress and enhancing SOD2 expression. Pretreatment with the mix activated the NRF2 pathway and was more effective than Saffron alone in preventing caspase-1 activation. These findings suggest that the combination of Saffron, Elderberry and Melilotus could have therapeutic potential in the prevention and treatment of retinal degenerative diseases.

The relationship between different stages of diabetic retinopathy and levels of YKL-40 in aqueous humour and serum

CLINICAL RELEVANCE

Since inflammation plays an important role in the pathogenesis of diabetic retinopathy, serum biomarkers and retinal imaging aimed at evaluating the presence of inflammation have emerged as useful tools to monitor the appearance and progression of diabetic retinopathy.

BACKGROUND

This study aims to investigate the value of YKL-40 levels in patients with diabetes mellitus with different stages of diabetic retinopathy and without diabetic retinopathy, and to compare those findings with results from healthy individuals without diabetes mellitus.

METHODS

This prospective cross-sectional study included 67 diabetic patients with or without diabetic retinopathy who underwent cataract surgery and 23 patients (control group) having no ocular and systemic disease other than senile cataract. Participants with diabetes mellitus were separated into three subgroups: the first group consisted of 26 patients without diabetic retinopathy, the second group included 21 patients with non-proliferative diabetic retinopathy and the third group included 20 patients with proliferative diabetic retinopathy. Serum and aqueous humour YKL-40 levels were analysed and compared between the groups.

RESULTS

The mean serum (p < 0.001) and aqueous humour (p < 0.001) YKL-40 levels were statistically significantly lower in control subjects compared to patients with diabetes mellitus. The aqueous humour YKL-40 levels showed statistically significant elevations with the progression of diabetic retinopathy. Duration of diabetes mellitus was significantly correlated with aqueous humour YKL-40 levels (p = 0.001, r = 0.384).

CONCLUSION

Both serum and aqueous humour YKL-40 levels are higher in patients with diabetes mellitus compared to healthy subjects. Levels of YKL-40 in aqueous humour increase with the progression of diabetic retinopathy.

YAP1 overexpression aggravates the progress of diabetic retinopathy by activating the TUG1/miR-144-3p/VEGFA signaling pathway in the hypoxia-induced DR MRMECs model

Diabetic retinopathy (DR) has been proven to be a leading cause of blindness. This study aimed to investigate the effect of Yes-associated protein 1 (YAP1) on the hypoxia-induced DR mice retinal microvascular endothelial cells (MRMECs) model. The hypoxia-induced DR MRMECs model was generated by treating in hypoxia circumstance (5 % CO2 and 3 % O2) for 48 h. This study constructed YAP1 overexpression and taurine-upregulated gene 1 (TUG1) silencing lentiviral vectors, both of which were used to infect the DR MRMECs model. Quantitative real-time PCR (qRT-PCR) was used to amplify the YAP1, TUG1, vascular endothelial growth factor A (VEGFA), and miR-144-3p gene. Western blot was used to identify the expression of YAP1 and VEGFA. The CCK-8 assay was used to evaluate proliferation and the flow cytometry assay was used to determine apoptosis of MRMECs. Cell migration and tube formation were also evaluated. The results showed that YAP1 overexpression and TUG1 silencing lentivirus were successfully constructed. YAP1 overexpression significantly promoted, but TUG1 silence inhibited cell proliferation and migration compared to DR MRMECs model (P<0.05). YAP1 markedly promoted TUG1/VEGFA and reduced miR-144-3p gene transcription compared to those of the DR MRMECs model (P<0.05). YAP1 overexpression and TUG1 silence demonstrated the opposite effects on VEGFA expression. YAP1 overexpression obviously promoted tube formation of MRMECs. In conclusion, overexpression of YAP1 promoted cell proliferation, cell migration, TUG1 and VEGFA expression, and reduced the transcription of the miR-144-3p gene in DR MRMECs. Overexpression of YAP1 aggravated the progress of DR in MRMECs by activating the TUG1/miR-144-3p/VEGFA signaling pathway.

Ent-pimarane and ent-kaurane diterpenoids from Siegesbeckiapubescens and their anti-endothelial damage effect in diabetic retinopathy

Diabetic retinopathy, a prevalent and vision-threatening microvascular complication of diabetes mellitus, is the leading cause of blindness among middle-aged and elderly individuals. Natural diterpenoids isolated from Siegesbeckia pubescens demonstrate potent anti-inflammatory properties. This study aimed to identify novel bioactive diterpenoids from S. pubescens and investigate their effects on oxidative stress and inflammatory responses in diabetic retinopathy, both in vitro and in vivo. Three new ent-pimarane-type diterpenoids (1-3) and six known compounds (4-9) were isolated from the aerial parts of S. pubescens. Their structures were elucidated through spectroscopic data interpretation, and absolute configurations were determined by comparing calculated and experimental electronic circular dichroism (ECD) spectra. Among these compounds, 14β,16-epoxy-ent-3β,15α,19-trihydroxypimar-7-ene (5) exhibited the most potent protective effect against high glucose and interleukin-1β (IL-1β)-stimulated human retinal endothelial cells. Mechanistically, compound 5 promoted endothelial cell survival while ameliorating oxidative stress and inflammatory response in diabetic retinopathy, both in vivo and in vitro. These findings not only suggest that diterpenoids such as compound 5 are important anti-inflammatory constituents in S. pubescens, but also indicate that compound 5 may serve as a lead compound for preventing or treating vascular complications associated with diabetic retinopathy.

Activated Growth Factor From Platelets as Treatment for Diabetic Retinopathy Through Antioxidant-Oxidative Stress Pathway

Background

Reactive oxygen species (ROS) is known to play a significant role in the activation of chronic inflammatory processes in diabetic retinopathy. This study was aimed to evaluate activated growth factor (AGF) from platelet for diabetic retinopathy treatment, utilizing an in vivo investigation to regulate the antioxidant-oxidative stress pathway.

Methods

The activated growth factor was initially derived by extracting intravenous blood from the rats. Advanced glycation end products (AGEs), p38 mitogen activated protein kinase (p38 MAPK), nuclear factor-κβ (NF-κβ), reactive oxygen species (ROS), tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), vascular cell adhesion molecule-1 (VCAM-1), intercellular adhesion molecule-1 (ICAM-1), superoxide dismutase (SOD) and vascular endothelial growth factor (VEGF) was assessed using enzyme linked immunoassay (ELISA). In vivo, diabetic retinopathy rat models were induced by streptozotocin injection and were evaluated by retinal funduscopy.

Results

The mean diameter of the retinal artery was significantly reduced when activated growth factor with transforming growth factor-β concentration of 10 ng/mL or 100 ng/mL was administered (p<0.05). The retinal tissue of diabetic rats showed a decline in antioxidant activity due to oxidative stress. AGF containing TGF-β (10 ng/mL and 100 ng/mL) significantly increased SOD activity (p<0.05). AGF administration effectively decreased proinflammatory cytokines like TNF-α and IL-1β.

Conclusion

The study shows that AGF, with TGF-β concentrations of 10 ng/mL and 100 ng/mL, can reduce AGEs, p38MAPK, Nf-κβ, ROS, TNF-α, IL-1β, VCAM-1, ICAM-1, and VEGF in diabetic retinopathy rats' retinal tissue, while increasing antioxidant SOD concentration, suggesting AGF may help treat diabetic retinopathy by reducing inflammation and oxidative stress.

Therapeutic effects of Mudan granules on diabetic retinopathy: Mitigating fibrogenesis caused by FBN2 deficiency and inflammation associated with TNF-α elevation

ETHNOPHARMACOLOGICAL RELEVANCE

Mudan granules (MuD), a time-honored traditional Chinese patent medicine (TCPM), are widely utilized in the clinical treatment of diabetic peripheral neuropathy (DPN). In the field of biomedical diagnostics, both diabetic retinopathy (DR) and DPN are recognized as critical microvascular complications associated with diabetes. According to the principles of traditional Chinese medicine (TCM), these conditions are primarily attributed to a deficiency in Qi and the obstruction of collaterals. Despite this, the protective effects of MuD on DR and the underlying mechanisms remain to be comprehensively elucidated.

AIMS OF THE STUDY

The purpose of this study was to investigate the effect of MuD on DR and to further explore the promising therapeutic targets.

METHODS

A diabetic mouse model was established by administering 60 mg/kg of streptozotocin (STZ) via intraperitoneal injection for five consecutive days. The therapeutic efficacy of MuD was evaluated using a comprehensive approach, which included electroretinogram (ERG) analysis, histopathological examination, and assessment of serum biochemical markers. Then, the pharmacodynamic mechanisms of MuD were systematically analyzed using Tandem Mass Tags-based proteomics. Meanwhile, the candidate compounds of MuD were analyzed by ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS) and molecular docking was applied to estimate the affinity of the active ingredient to their potential key targets. In addition, the functional mechanisms identified through bioinformatics analysis were confirmed by molecular biological methods.

RESULTS

We demonstrated that MuD provided significant protection to retinal function and effectively mitigated the reduction in retinal thickness observed in the animal model. Through proteomic analysis, we identified a substantial regulation by MuD of 70 biomarkers associated with diabetic retinal damage. These proteins were notably enriched in the tumor necrosis factor (TNF) signaling pathway, a critical mediator in inflammatory processes. A particularly intriguing finding was the significant downregulation of fibrillin-2 (FBN2) in the diabetic retina compared to the control group (0.36 times the level), and its most pronounced upregulation (3.26 times) in the MuD treatment group. This suggests that FBN2 may play a pivotal role in the protective effects of MuD. Molecular docking analyses have unveiled a robust interplay between the components of MuD and TNF-α. Further corroboration was provided by molecular biological methods, which confirmed that MuD could suppress TNF-mediated inflammation and prevent retinal neovascularization and fibrogenesis.

CONCLUSION

MuD have the potential to alleviate diabetic retinal dysfunction by effectively curbing the fibrogenesis-associated neoangiogenesis and mitigating the inflammatory response, thereby restoring retinal health and function.

Future Directions in Diabetic Retinopathy Treatment: Stem Cell Therapy, Nanotechnology, and PPARα Modulation

This narrative review focuses on innovative treatment approaches to diabetic retinopathy to meet the urgent demand for advancements in managing both the early and late stages of the disease. Recent studies highlight the potential of adipose stem cells and their secreted factors in mitigating the retinal complications of diabetes, with promising results in improving visual acuity and reducing inflammation and angiogenesis in diabetic retinopathy. However, caution is warranted regarding the safety and long-term therapeutic effects of adipose stem cells transplantation. Bone marrow mesenchymal stem cells can also mitigate retinal damage in diabetic retinopathy. Studies demonstrate that bone marrow mesenchymal stem cells-derived exosomes can suppress the Wnt/β-catenin pathway, reducing oxidative stress, inflammation, and angiogenesis in the diabetic retina, offering promise for future diabetic retinopathy treatments. Nanotechnology has the ability to precisely target the retina and minimize systemic side effects. Nanoparticles and nanocarriers offer improved bioavailability, sustained release of therapeutics, and potential for synergistic effects. They can be a new way of effective treatment and prevention of diabetic retinopathy. Activation and modulation of PPARα as a means for diabetic retinopathy treatment has been widely investigated in recent years and demonstrated promising effects in clinical trials. PPARα activation turned out to be a promising therapeutic method for treating dyslipidemia, inflammation, and insulin sensitivity. The combination of PPARα modulators with small molecules offers an interesting perspective for retinal diseases' therapy.

Correlation Between the Ratio of Uric Acid to High-Density Lipoprotein Cholesterol (UHR) and Diabetic Retinopathy in Patients with Type 2 Diabetes Mellitus:A Cross-Sectional Study

Background/Objective

Considering the uncertain relationship between high-density lipoprotein cholesterol (HDL-C) and uric acid (UA) with diabetic retinopathy (DR),this study investigates the link between Uric Acid to High-Density Lipoprotein Cholesterol (UHR) and DR in T2DM patients, evaluating its potential for DR diagnosis and early prediction.

Study Design and Data Collection

This retrospective study analyzed 1450 type 2 diabetes patients, divided into NDR and DR groups by retinal exams. We gathered demographic and clinical data, calculated UHR, and explored its correlation with DR development.

Outcomes

Individuals diagnosed with diabetic retinopathy (DR) exhibited a markedly elevated uric acid to high-density lipoprotein cholesterol (UHR) ratio when contrasted with those without DR (NDR), achieving statistical significance with a P-value below 0.001. The Mantel-Haenszel chi-square test for linear association validated a pronounced positive correlation between the UHR ratio and the incidence of DR (P<0.001). Binary logistic regression analysis revealed that age, glycated hemoglobin (HbA1c), uric acid (UA), high-density lipoprotein cholesterol (HDL-C), and the UHR ratio were all independent risk factors for the development of DR in patients with type 2 diabetes. Furthermore, the receiver operating characteristic (ROC) curve analysis indicated that the UHR ratio was the most precise predictor for diagnosing DR, with an area under the ROC curve (AUC) of 78.4%, a sensitivity of 87%, and a specificity of 60.6%.

Conclusion

Our research has found that the UHR ratio is an independent risk factor for diabetic retinopathy (DR) in patients with type 2 diabetes and can serve as a readily available indicator that takes into account both metabolic status and inflammatory status for the early detection of DR.

IL-1β-induced pericyte dysfunction with a secretory phenotype exacerbates retinal microenvironment inflammation via Hes1/STAT3 signaling pathway

Retinal pericytes are mural cells surrounding capillaries to maintain the integrity of blood-retina barrier and regulate vascular behaviors. Pericyte loss has been considered as the hallmark of diabetic retinopathy (DR), which is a major complication of diabetes and the leading cause of blindness in adults. However, the precise function of pericytes in regulating the retinal microenvironment and the underlying mechanism remains largely unknown. In this study, we observed a secretory phenotype of pericytes with elevated inflammatory cytokines in response to Interleukin-1β (IL-1β), a canonical inflammatory cytokine which significantly increases during the initial stages of diabetic retinopathy. This phenotype is also accompanied by reduced expression of adherent junction proteins and contractile proteins. Paracrine cytokines derived from pericytes further induce the chemotaxis of microglia cells and trigger detrimental changes in endothelial cells, including reduced expression of tight junction protein Occludin and increased apoptosis. Mechanically, the secretion potential in pericytes is partially mediated by Hes1/STAT3 signaling pathway. Moreover, co-injection of stattic, an inhibitor targeting STAT3 activation, could effectively attenuate IL-1β-induced retinal inflammation and microglial activation in retina tissues. Collectively, these findings demonstrate the potential of retinal pericytes as an initial inflammatory sensor prior to their anatomical pathological loss, via undergoing phenotypic changes and secreting paracrine factors to amplify local inflammation and damage endothelial cells in vitro. Furthermore, inhibition of STAT3 activation by inhibitors significantly ameliorates IL-1β-induced retinal inflammation, suggesting STAT3 in retinal pericytes as a promising target for alleviating DR and other IL-1β-induced ocular diseases.

Retinal OCT-Derived Texture Features as Potential Biomarkers for Early Diagnosis and Progression of Diabetic Retinopathy

Purpose

Diabetic retinopathy (DR) is usually diagnosed many years after diabetes onset. Indeed, an early diagnosis of DR remains a notable challenge, and, thus, developing novel approaches for earlier disease detection is of utmost importance. We aim to explore the potential of texture analysis of optical coherence tomography (OCT) retinal images in detecting retinal changes in streptozotocin (STZ)-induced diabetic animals at "silent" disease stages when early retinal molecular and cellular changes that cannot be clinically detectable are already occurring.

Methods

Volume OCT scans and electroretinograms were acquired before and 1, 2, and 4 weeks after diabetes induction. Automated OCT image segmentation was performed, followed by retinal thickness and texture analysis. Blood-retinal barrier breakdown, glial reactivity, and neuroinflammation were also assessed.

Results

Type 1 diabetes induced significant early changes in several texture metrics. At week 4 of diabetes, autocorrelation, correlation, homogeneity, information measure of correlation II (IMCII), inverse difference moment normalized (IDN), inverse difference normalized (INN), and sum average texture metrics decreased in all retinal layers. Similar effects were observed for correlation, homogeneity, IMCII, IDN, and INN at week 2. Moreover, the values of those seven-texture metrics described above decreased throughout the disease progression. In diabetic animals, subtle retinal thinning and impaired retinal function were detected, as well as an increase in the number of Iba1-positive cells (microglia/macrophages) and a subtle decrease in the tight junction protein immunoreactivity, which did not induce any physiologically relevant effect on the blood-retinal barrier.

Conclusions

The effects of diabetes on the retina can be spotted through retinal texture analysis in the early stages of the disease. Changes in retinal texture are concomitant with biological retinal changes, thus unlocking the potential of texture analysis for the early diagnosis of DR. However, this requires to be proven in clinical studies.

Induction of a Müller Glial Cell-Specific Protective Pathway Safeguards the Retina From Diabetes-Induced Damage

Diabetes can lead to cell type-specific responses in the retina, including vascular lesions, glial dysfunction, and neurodegeneration, all of which contribute to retinopathy. However, the molecular mechanisms underlying these cell type-specific responses, and the cell types that are sensitive to diabetes have not been fully elucidated. Using single-cell transcriptomics, we profiled the transcriptional changes induced by diabetes in different retinal cell types in rat models as the disease progressed. Rod photoreceptors, a subtype of amacrine interneurons, and Müller glial cells (MGs) exhibited rapid responses to diabetes at the transcript levels. Genes associated with ion regulation were upregulated in all three cell types, suggesting a common response to diabetes. Furthermore, focused studies revealed that although MG initially increased the expression of genes playing protective roles, they cannot sustain this beneficial effect. We explored one of the candidate protective genes, Zinc finger protein 36 homolog (Zfp36), and observed that depleting Zfp36 in rat MGs in vivo using adeno-associated virus-based tools exacerbated diabetes-induced phenotypes, including glial reactivation, neurodegeneration, and vascular defects. Overexpression of Zfp36 slowed the development of these phenotypes. This work unveiled retinal cell types that are sensitive to diabetes and demonstrated that MGs can mount protective responses through Zfp36.

ARTICLE HIGHLIGHTS

Lights and Shadows of Cytokines in Age-Related Eye Diseases: A Narrative Literature Review

The eye is considered to be an immune-privileged region. However, several parts of the eye have distinct mechanisms for delivering immune cells to the injury sites or even in response to aging. Although these immune responses are intended to be protective, the visual acuity can be compromised by the release of pro-inflammatory cytokines by immune cells, which induce chronic inflammation and fibrosis. Age-related eye diseases (AREDs) are the primary cause of vision impairment (VI) in the elderly, with a poor comprehension of their pathophysiology. Age-related eye diseases affect both the anterior and posterior segments, resulting in diminished quality of life and risk of irreversible blindness. Immune system dysregulation and the upregulation of pro-inflammatory cytokines have been linked to AREDs, underscoring the need to comprehend inflammation's impact on ocular disorders to enhance patient symptom management. In this framework, the PubMed database was searched using the medical subject headings (MeSH) terms "Age-related eye diseases," "dry eye syndrome," "glaucoma," "cataract," "diabetic retinopathy," "inflammation," "interleukin," and "cytokine" with the aim of overview the role of cytokines in AREDs and discuss their potential therapeutic approaches.

Unveiling the intricacies of chronic kidney disease: From ocular manifestations to therapeutic frontiers

BACKGROUND

Shared anatomical, histological and physiological pathways between the kidney and the eye are well documented, demonstrating that ocular manifestations serve as valuable prognostic indicators in chronic kidney disease (CKD), providing insights into disease severity and progression. Through non-invasive imaging modalities such as retinal fundus photography, early retinal microvascular alterations indicative of CKD progression can be detected, enabling timely intervention and risk stratification. However, the conclusions drawn from the review primarily demonstrate a strong or independent association between glaucoma or retinopathy and CKD.

RESULTS AND CONCLUSION

Multiple shared pathophysiological events have been implicated in the pathogenesis in the alterations at eye and kidney including renin-angiotensin-aldosterone system. Patients with CKD are more likely to experience glaucoma, age-related macular degeneration, cataracts, uremic optic neuropathy and retinopathy. To establish the role of ocular manifestations in predicting CKD progression, it is crucial to address the limitations of correlation and explore the underlying causality with further research on common disease pathogenesis. Additionally, specific methods for risk stratification based on retinal changes, the effectiveness of timely interventions, and the development of predictive tools combining ocular and renal data are of utmost importance research topics to enlighten the bidirectional causality.

Innovative Hydrogel Design: Tailoring Immunomodulation for Optimal Chronic Wound Recovery

Despite significant progress in tissue engineering, the full regeneration of chronic wounds persists as a major challenge, with the immune response to tissue damage being a key determinant of the healing process's quality and duration. Post-injury, a crucial aspect is the transition of macrophages from a pro-inflammatory state to an anti-inflammatory. Thus, this alteration in macrophage polarization presents an enticing avenue within the realm of regenerative medicine. Recent advancements have entailed the integration of a myriad of cellular and molecular signals into hydrogel-based constructs, enabling the fine-tuning of immune cell activities during different phases. This discussion explores modern insights into immune cell roles in skin regeneration, underscoring the key role of immune modulation in amplifying the overall efficacy of wounds. Moreover, a comprehensive review is presented on the latest sophisticated technologies employed in the design of immunomodulatory hydrogels to regulate macrophage polarization. Furthermore, the deliberate design of hydrogels to deliver targeted immune stimulation through manipulation of chemistry and cell integration is also emphasized. Moreover, an overview is provided regarding the influence of hydrogel properties on immune traits and tissue regeneration process. Conclusively, the accent is on forthcoming pathways directed toward modulating immune responses in the milieu of chronic healing.

[Lipoprotein-associated phospholipase A2 (Lp-PLA2): Relevant biomarker and therapeutic target?]

Over the last fifteen years, numerous studies have sought to decipher the role of lipoprotein-associated phospholipase A2 (Lp-PLA2) in vascular inflammation-related diseases, notably atherosclerosis. Despite the disappointing results of clinical trials using the Lp-PLA2 inhibitor darapladib, new pathophysiological, epidemiological and genetic data have enabled the development of new inhibitors. Recent studies also show that Lp-PLA2 is involved in vascular inflammation-related diseases other than atherosclerosis (ischemic stroke, Alzheimer's disease and vascular dementia, diabetes, cancers…), and inhibition of Lp-PLA2 could have beneficial therapeutic in these diseases. This review aims to present new data on Lp-PLA2 and to evaluate its current interest as a biomarker but also as a therapeutic target.

The IL-12 family of cytokines: pathogenetic role in diabetic retinopathy and therapeutic approaches to correction

One vision-threatening side effect of systematic diabetes mellitus is diabetic retinopathy (DR). Recent studies have revealed that the development and progression of DR depend critically on inflammation resulting from diabetes. By attracting leukocytes to endothelium, the higher production of the inflammatory mediators induces degeneration of retinal capillaries, hence increasing vascular permeability and thrombosis probability. The leukocytes that are recruited eventually generate additional proinflammatory and proangiogenic substances, resulting in the increased infiltration of leukocytes in the retina. This process also leads to changes in the blood retinal barrier and the formation of new blood vessels, which helps to counteract the damage caused by the blockage of blood flow. IL-12 family members, IL-12, IL-23, IL-27, and IL-35, play a crucial role in regulating the responses of T helper (Th)1 and Th17 cell populations. The collected data from studies investigating the levels of IL-12 family members in the blood and eye tissues suggest that IL-12 is linked to DR, indicating that it may have a role in the development of DR as a sequential component of the immune response. This review specifically examines the possibility of using IL-12 family cytokines as a therapeutic approach for diabetes, taking into consideration their involvement in the development of DR.

Serum inflammation biomarkers level in cystoid and diffuse diabetic macular edema

OBJECTIVE

To assess serum inflammatory biomarker levels in patients with different subtypes of diabetic macular edema (DME).

METHODS

We retrospectively analyzed 50 eyes from 37 treatment-naïve DME patients who underwent intravitreal injection therapy between June and December 2023. Based on the morphological characteristics of macular edema in optical coherence tomography (OCT), the eyes were categorized into the cystoid macular edema (CME) group (n = 25) and diffuse retinal thickening (DRT) group (n = 25). Additionally, 25 eyes with diabetes retinopathy but without DME served as the control group. Comprehensive clinical data were reviewed, including best-corrected visual acuity (BCVA), central macular thickness (CMT), macular cube volume (VOL) and hematological examination. The neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and systemic immune-inflammation index (SII) were calculated.

RESULTS

NLR and SII levels were significantly higher in the CME group compared to the DRT group and control group (all P < 0.01). The optimal ROC cutoff value of NLR for CME was 2.27, with 88.0% sensitivity and 68.0% specificity. The optimal ROC cutoff value of SII for CME was 447.33, with 84.0% sensitivity and 60.0% specificity. After initial intravitreal injection therapy, BCVA and VOL significantly improved in each group (all P < 0.01). However, no significant correlation was found between systemic inflammatory marker levels and postoperative changes in BCVA, CMT and VOL (all P > 0.05).

CONCLUSION

Our study suggests that elevated NLR and SII levels are significantly associated with CME. Elevated serum inflammatory biomarkers may indicate a higher incidence of CME in these patients.

Underlying mechanisms of traditional Chinese medicine in the prevention and treatment of diabetic retinopathy: Evidences from molecular and clinical studies

As one of the most serious microvascular complications of diabetes mellitus (DM), diabetic retinopathy (DR) can cause visual impairment and even blindness. With the rapid increase in the prevalence of DM, the incidence of DR is also rising year by year. Preventing and effectively treating DR has become a major focus in the medical field. Traditional Chinese medicine (TCM) has a wealth of experience in treating DR and has achieved significant results with various herbs and TCM prescriptions. Traditional Chinese Medicine (TCM) provides a comprehensive therapeutic strategy for diabetic retinopathy (DR), encompassing anti-inflammatory and antioxidant actions, anti-neovascularization, neuroprotection, regulation of glucose metabolism, and inhibition of apoptosis. This review provides an overview of the current status of TCM treatment for DR in recent years, including experimental studies and clinical researches, to explore the clinical efficacy and the underlying modern mechanisms of herbs and TCM prescriptions. Besides, we also discussed the challenges TCM faces in treating DR, such as drug-drug interactions among TCM components and the lack of high-quality evidence-based medicine practice, which pose significant obstacles to TCM's application in DR.

Integrative analysis of PANoptosis-related genes in diabetic retinopathy: machine learning identification and experimental validation

Background

Diabetic retinopathy (DR) is a major complication of diabetes, leading to severe vision impairment. Understanding the molecular mechanisms, particularly PANoptosis, underlying DR is crucial for identifying potential biomarkers and therapeutic targets. This study aims to identify differentially expressed PANoptosis-related genes (DE-PRGs) in DR, offering insights into the disease's pathogenesis and potential diagnostic tools.

Methods

DR datasets were obtained from the Gene Expression Omnibus (GEO) database, while PANoptosis-related genes were sourced from the GeneCards database. Differentially expressed genes (DEGs) were identified using the DESeq2 package, followed by functional enrichment analysis through DAVID and Metascape tools. Three machine learning algorithms-LASSO regression, Random Forest, and SVM-RFE-were employed to identify hub genes. A diagnostic nomogram was constructed and its performance assessed via ROC analysis. The CIBERSORT algorithm analyzed immune cell infiltration. Hub genes were validated through RT-qPCR, Western blotting, immunohistochemistry, and publicly available datasets. Additionally, the impact of FASN and PLSCR3 knockdown on HUVECs behavior was validated through in vitro experiments.

Results

Differential expression analysis identified 1,418 DEGs in the GSE221521 dataset, with 39 overlapping DE-PRGs (29 upregulated, 10 downregulated). Functional enrichment indicated that DE-PRGs are involved in apoptosis, signal transduction, and inflammatory responses, with key pathways such as MAPK and TNF signaling. Machine learning algorithms identified six PANoptosis-related hub genes (BEX2, CASP2, CD36, FASN, OSMR, and PLSCR3) as potential biomarkers. A diagnostic nomogram based on these hub genes showed high diagnostic accuracy. Immune cell infiltration analysis revealed significant differences in immune cell patterns between control and DR groups, especially in Activated CD4 Memory T Cells and Monocytes. Validation confirmed the diagnostic efficiency and expression patterns of the PANoptosis-related hub genes, supported by in vitro and the GSE60436 dataset analysis. Furthermore, experiments demonstrated that knocking down FASN and PLSCR3 impacted HUVECs behavior.

Conclusion

This study provides valuable insights into the molecular mechanisms of DR, particularly highlighting PANoptosis-related pathways, and identifies potential biomarkers and therapeutic targets for the disease.

Letter to Editor: Comment on Ioanna Tsioti et al. "Systemic Lipopolysaccharide Exposure Exacerbates Choroidal Neovascularization in Mice"

This study by Ioanna Tsioti and colleagues delves into the exacerbation of choroidal neovascularization (CNV) through systemic exposure to lipopolysaccharide (LPS) in a mouse model. The research highlights the molecular and cellular mechanisms by which systemic inflammation can influence ocular conditions, particularly in the context of age-related macular degeneration (AMD). Utilizing a combination of in vivo fluorescein angiography, in situ hybridization, and flow cytometry, the study provides critical insights into the dynamic interaction between systemic inflammatory stimuli and CNV progression. Key findings include increased infiltration of monocyte-derived macrophages and enhanced Vegfα mRNA expression in Glul-expressing cells following systemic LPS exposure. These results suggest potential therapeutic targets for mitigating CNV associated with systemic inflammatory responses.

Induction, amplification, and propagation of diabetic retinopathy-associated inflammatory cytokines between human retinal microvascular endothelial and Müller cells and in the mouse retina

Ocular levels of IL-1β, TNFα, IL-8, and IL-6 correlate with progression of diabetic retinopathy (DR). Müller cells (MC), which are crucial to maintaining retinal homeostasis, are targets and sources of these cytokines. We explored the relative capacities of these four DR-associated cytokines to amplify inflammatory signal expression both in and between human MC (hMC) and retinal microvascular endothelial cells (hRMEC) and in the mouse retina. Of the four cytokines, IL-1β was the most potent stimulus of transcriptomic alterations in hMC and hRMEC in vitro, as well as in the mouse retina after intravitreal injection in vivo. Stimulation with IL-1β significantly induced expression of all four transcripts in hMC and hRMEC. TNFα significantly induced expression of some, but not all, of the four transcripts in each cell, while neither IL-8 nor IL-6 showed significant induction in either cell. Similarly, conditioned media (CM) derived from hMC or hRMEC treated with IL-1β, but not TNFα, upregulated inflammatory cytokine transcripts in the reciprocal cell type. hRMEC responses to hMC-derived CM were dependent on IL-1R activation. In addition, we observed a correlation between cytokine expression changes following direct and CM stimulation and NFκB-p65 nuclear translocation in both hMC and hRMEC. Finally, in mice, intravitreal injections of IL-1β, but not TNFα, induced retinal expression of Il1b and CXCL8 homologues Cxcl1, Cxcl2, Cxcl3, and Cxcl5, encoding pro-angiogenic chemokines. Our results suggest that expression of IL-1β, TNFα, IL-8, and IL-6 may be initiated, propagated, and sustained by autocrine and paracrine signals in hRMEC and hMC through a process involving IL-1β and NFκB. Targeting these signals may help thwart inflammatory amplification, preventing progression to vision-threatening stages and preserving sight.

Macromolecules from mushrooms, venoms, microorganisms, and plants for diabetes treatment - Progress or setback?

Diabetes is a substantial public health issue, while its prevalence continues to rise worldwide, affecting millions of persons between the ages of 20 and 80, the development of new therapeutic classes improving glycemic control and consequently micro and macrovascular complications are needed. Today, diabetes treatment is daily for life, and should not be interrupted. However, insulin secretagogues medications, and exogenous self-administration of insulin provide efficient antidiabetic effects, but their misuse leads to hypoglycemic complications besides other risks, hence the need to look for other natural products not to use solely but in concert with others types of medications. In this review, we will highlight briefly the pathophysiology of diabetes and its complications, then we will report the main bioactive macromolecules derived from various sources of natural products providing anti-diabetic properties. However, further researches need to be carried out to face the limitations hampering the development of effective natural drugs for diabetes treatment.

Transcriptome combined with Mendelian randomization to screen key genes associated with mitochondrial and programmed cell death causally associated with diabetic retinopathy

Background

Mitochondrial dysfunction in the retina can induce apoptosis of retinal capillary cells, leading to diabetic retinopathy (DR). This study aimed to explore key genes related to programmed cell death (PCD) and mitochondria in DR via bioinformatic analysis.

Methods

A differential analysis was performed to identify differentially expressed genes (DEGs) between DR and control samples using the GSE94019 dataset from the Gene Expression Omnibus (GEO) database. Pearson correlation analysis was then utilized to select genes linked to mitochondrial function and PCD (M-PCD). Candidate genes were identified by overlapping DR-DEGs and M-PCD genes, followed by functional annotation. Mendelian randomization (MR) analysis was employed to identify genes with causal relationships to DR. Key genes were identified through protein-protein interaction (PPI) analysis using six algorithms (DEgree, DMNC, EPC, MCC, Genes are BottleNeck, and MNC) within Cytoscape software. The expression patterns of these genes were validated using GSE94019 and GSE60436 datasets, as well as RT-qPCR. Enrichment analysis provided insights into the function and pathways of these key genes in DR. Differential immune cell profiles were determined via immune infiltration analysis, followed by exploring the relationships between immune cells, cytokines, and the identified genes. Correlations between key genes and apoptosis genes were also examined. In vivo experiments using RT-PCR, immunohistochemistry (IHC), and western blot analysis confirmed that MYC and SLC7A11 expression was significantly elevated in DR rat retinal tissues.

Results

From 658 candidate genes, 12 showed significant causal associations with DR. MYC and SLC7A11 were particularly notable, showing upregulated expression in DR samples and involvement in apoptosis and diabetes-related pathways. These genes were significantly associated with apoptotic genes and correlated positively with altered immune cell types and cytokines, suggesting a link between immune response and DR pathogenesis. In vivo findings confirmed that MYC and SLC7A11 expression was elevated in DR rat retinal tissues.

Conclusion

Key genes (MYC and SLC7A11) associated with mitochondrial function and PCD in DR were identified, offering insights into DR's pathological mechanisms and potential targets for diagnostic and therapeutic strategies.

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 understanding 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.

Association Between Triglyceride-Glucose Index and Diabetic Retinopathy: A Meta-Analysis

The objective of this study was to assess the relationship between the triglyceride-glucose (TyG) index, a recently proposed marker of insulin resistance, and the occurrence of diabetic retinopathy (DR), a complication associated with cardiovascular risk. This systematic review and meta-analysis aimed to evaluate the association between the TyG index and DR. To achieve the objective of the meta-analysis, an extensive search was conducted on databases such as PubMed, Embase, and Web of Science to identify observational studies with longitudinal follow-up. Random-effects models were employed to combine the findings, taking into account the potential influence of heterogeneity. Twelve observational studies from 11 reports were included in the meta-analysis, which involved 16 259 patients with type 2 diabetes (T2D). Among them, 4302 (26.5%) were diagnosed as DR. Pooled results showed that a higher TyG index was associated with a higher risk of DR [odds ratio (OR) for the fourth versus the first quartile of TyG index: 1.91, 95% confidence interval (CI): 1.44 to 2.53, p<0.001; I2=72%]. Meta-analysis of TyG index analyzed in continuous variable showed consistent results (OR for per 1 unit increment of TyG index: 1.41, 95% CI: 1.08 to 1.86, p=0.01; I2=82%). Subgroup analysis showed that adjustment of HbA1c or the duration of diabetes did not significantly affect the results (p for subgroup difference all>0.05). In conclusion, a high TyG index was associated with the risk of DR in T2D patients.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Modulatory Effects of 830 nm on Diabetic Wounded Fibroblast Cells: An In Vitro Study on Inflammatory Cytokines

Background:After skin damage, a complicated set of processes occur for epidermal and dermal wound healing. This process is hindered under diabetic conditions, resulting in nonhealing diabetic ulcers. In diabetes there is an increase in inflammation and proinflammatory cytokines. Modulating cells using photobiomodulation (PBM) may have an effect on inflammation and cell viability, which are crucial for the healing of wounds. Objective: This study explored the impact of PBM in the near-infrared spectrum (830 nm; 5 J/cm2) on inflammation in diabetic wound healing. Materials and Methods: Five cell models, namely normal, wounded, diabetic, diabetic wounded, and wounded with d-galactose were used. Cell morphology and migration rate were assessed, while cellular response measures included viability (Trypan blue and adenosine triphosphate), apoptosis (annexin-V/PI), proinflammatory cytokines interleukin-6, tumor necrosis factor-alpha (TNF-α), and cyclooxygenase-2, nuclear translocation of nuclear factor kappa B (NF-κB), and gene expression of advanced glycation end product receptor (AGER). Results: PBM resulted in increased levels of TNF-α, supported by activation of NF-κB. PBM stimulated translocation of NF-κB and upregulation of AGER. Conclusions: PBM modulates diabetic wound healing in vitro at 830 nm through stimulated NF-κB signaling activated by TNF-α.

Role of inflammation in diabetic macular edema and neovascular age-related macular degeneration

Diabetic macular edema (DME) and neovascular age-related macular degeneration (nAMD) are multifactorial disorders that affect the macula and cause significant vision loss. Although inflammation and neoangiogenesis are hallmarks of DME and nAMD, respectively, they share some biochemical mediators. While inflammation is a trigger for the processes that lead to the development of DME, in nAMD inflammation seems to be the consequence of retinal pigment epithelium and Bruch membrane alterations. These pathophysiologic differences may be the key issue that justifies the difference in treatment strategies. Vascular endothelial growth factor inhibitors have changed the treatment of both diseases, however, many patients with DME fail to achieve the established therapeutic goals. From a clinical perspective, targeting inflammatory pathways with intravitreal corticosteroids has been proven to be effective in patients with DME. On the contrary, the clinical relevance of addressing inflammation in patients with nAMD has not been proven yet. We explore the role and implication of inflammation in the development of nAMD and DME and its therapeutical relevance.

Multimodal imaging in diabetic retinopathy and macular edema: An update about biomarkers

Diabetic macular edema (DME), defined as retinal thickening near, or involving the fovea caused by fluid accumulation in the retina, can lead to vision impairment and blindness in patients with diabetes. Current knowledge of retina anatomy and function and DME pathophysiology has taken great advantage of the availability of several techniques for visualizing the retina. Combining these techniques in a multimodal imaging approach to DME is recommended to improve diagnosis and to guide treatment decisions. We review the recent literature about the following retinal imaging technologies: optical coherence tomography (OCT), OCT angiography (OCTA), wide-field and ultrawide-field techniques applied to fundus photography, fluorescein angiography, and OCTA. The emphasis will be on characteristic DME features identified by these imaging technologies and their potential or established role as diagnostic, prognostic, or predictive biomarkers. The role of artificial intelligence in the assessment and interpretation of retina images is also discussed.

Polysaccharides from Ostrea rivularis alleviate type II diabetes induced-retinopathy and VGEF165-induced angiogenesis via PI3K/AKT signaling pathway

The purpose of this study was to investigate the role of polysaccharides from Ostrea rivularis Gloud (ORPs) in the progression of diabetic retinopathy (DR) and its anti-angiogenic effect on endothelial cell. Transgenic db/db mice with DR model were used to evaluate the protective effect of ORPs on retinal damage. It was found that ORPs could down-regulated levels of random blood glucose and fasting insulin, and further ameliorate retinal structure abnormalities as well as vascular network structure. Moreover, ORPs could reduce the expression of VEGF in retinal tissue and lessen pathological angiogenesis, thus slowing the progression of DR. In vitro, the proliferation, migration and tube formation of VGEF165-induced EA.hy926 cells were inhibited with ORPs administration. Furthermore, the expression of related proteins in the PI3K/AKT pathway and angiogenesis related factors were improved after ORPs intervention. Overall, these findings suggested that ORPs could effectively control the development of DR, and inhibit VGEF165-induced EA.hy926 cells proliferation, migration and tube formation, which effects might work through blocking the activation of PI3K/AKT signaling pathway.

Sex Differences in Inflammation-Related Biomarkers Detected with OCT in Patients with Diabetic Macular Edema

Purpose

To investigate sex-based differences in inflammation-related biomarkers on spectral-domain OCT.

Design

Cross-sectional study.

Participants

Patients with diabetic macular edema (DME) between February 1, 2019, and March 31, 2023, without intravitreal anti-VEGF injection within the previous 6 months.

Methods

We reviewed each patient's medical record for age, biological sex, race and ethnicity, most recent glycated hemoglobin A1c (HbA1c) level, visual acuity (VA), and central macular thickness (CMT). OCT biomarkers that have been found in literature to be associated with inflammation, including disorganization of retinal inner layers (DRIL), retinal hyperreflective retinal foci (HRFs), hyperreflective choroidal foci (HCFs), subfoveal neuroretinal detachment (SND), and perturbation in retinal nerve fiber layer thickness, ganglion cell layer thickness, and inner nuclear layer (INL) thickness were evaluated by graders masked to the clinical characteristics of the patients. We performed multivariable regression analyses with the OCT biomarkers as the outcome variables and sex, age, HbA1c, and CMT as independent variables.

Main Outcome Measures

OCT inflammation-related biomarkers, as listed above.

Results

Female patients were, on average, 2 years older than male patients (P = 0.041). There were no significant differences in race and ethnicity, HbA1c, VA, or CMT between male and female patients. After controlling for age, HbA1c, and CMT, we found male sex to be associated with more HRF (incidence rate ratio [IRR] = 1.19; 95% confidence interval [CI] = 1.10-1.29), more HCF (odds ratio = 2.01; 95% CI = 1.12-3.64), and thicker INL (7 μm thicker in males; 95% CI = 2-12). Sex was not a significant predictor for either DRIL or SND in the multivariable regression models. Patients with higher HbA1c were more likely to have more HRF (IRR = 1.02 per 1 point increase; 95% CI = 1.00-1.04) after controlling for other factors.

Conclusions

Male sex was correlated with more inflammation-related biomarkers on OCT including more HRF, more HCF, and thicker INL, after accounting for age, glycemic control, and amount of DME. Further studies are needed to evaluate the potential implications of these sex-based differences for individualized treatment.

Financial Disclosures

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

Retinal microglia-derived S100A9 incite NLRP3 inflammasome in a Western diet fed Ossabaw pig retina

Purpose

We established S100A9 as a myeloid-derived damage-associated molecular pattern (DAMPs) protein associated with increasing severity of diabetic retinopathy (DR) in type 2 diabetic subjects. The present study investigates the retinal localization, expression, and mechanisms of action for S100A9 in the young obese Ossabaw pig retina.

Methods

Retinae from Ossabaw pigs fed a Western diet for 10 weeks were evaluated for S100 and inflammatory mediator expression using quantitative PCR and Western blot. Double immunohistochemistry was performed to identify the cellular sources of S100A9 in the pig retina. Primary pig retinal microglial cells (pMicroglia) were examined for S100A9 production. S100A9-induced responses were also investigated, and inhibitor studies elucidated the mechanism of action via the NLRP3 inflammasome. A specific inhibitor, Paquinimod (ABR-215757), was administered in vitro to assess the rescue of S100A9-induced NLRP3 inflammasome activation in pMicroglia.

Results

The expression of the S100 family in the obese Ossabaw pig retina showed a significant elevation of S100A9, consistent with increased levels of circulating S100A9. Moreover, the retina had elevated levels of inflammatory mediators IL-6, IL-8, MCP-1, IL-1β and NLRP3. Retinal microglia in obese Ossabaw were activated and accompanied by an increased expression of intracellular S100A9. pMicroglia isolated from pig retina transformed from ramified to amoeboid state when activated with LPS and produced high S100A9 transcript and protein levels. The S100A9 protein, in turn, further activated pMicroglia by heightened production of S100A9 transcripts and secretion of pro-inflammatory IL-1β protein. Inhibition of TLR4 with TAK242 and NLRP3 with MCC950 attenuated the production of IL-1β during S100A9 stimulus. Finally, pre-treatment with Paquinimod successfully reduced S100A9-driven increases of glycosylated-TLR4, NLRP3, ASC, Caspase-1, and IL-1β production.

Conclusion

We demonstrated that microglial-derived S100A9 perpetuates pro-inflammatory responses via the NLRP3 inflammasome in the retina of young Western-diet-fed Ossabaw pigs exhibiting diabetic retinopathy.

The Role of Immune Cells and Signaling Pathways in Diabetic Eye Disease: A Comprehensive Review

Diabetic eye disease (DED) encompasses a range of ocular complications arising from diabetes mellitus, including diabetic retinopathy, diabetic macular edema, diabetic keratopathy, diabetic cataract, and glaucoma. These conditions are leading causes of visual impairments and blindness, especially among working-age adults. Despite advancements in our understanding of DED, its underlying pathophysiological mechanisms remain incompletely understood. Chronic hyperglycemia, oxidative stress, inflammation, and neurodegeneration play central roles in the development and progression of DED, with immune-mediated processes increasingly recognized as key contributors. This review provides a comprehensive examination of the complex interactions between immune cells, inflammatory mediators, and signaling pathways implicated in the pathogenesis of DED. By delving in current research, this review aims to identify potential therapeutic targets, suggesting directions of research for future studies to address the immunopathological aspects of DED.

hsa_circ_0000047 targeting miR-6720-5p/CYB5R2 axis alleviates inflammation and angiogenesis in diabetic retinopathy

Context: Diabetic retinopathy (DR) is a common complication of diabetes mellitus (DM). Circular RNAs (circRNAs) act as key regulators of DR development by regulating inflammation and angiogenesis.Objective: This study aimed to elucidate the function and mechanism of hsa_circ_0000047 in DR.Materials and methods: High glucose (HG) was used to induce human retinal microvascular endothelial cells (hRMECs) to construct a DR model in vitro. Qualitative real-time polymerase chain reaction (qRT-PCR) or western blotting were used to detected the levels of hsa_circ_0000047, miR-6720-5p, and CYB5R2 in DR and HG-indeced hRMECs. Cell functional experiments were performed to detect the change of viability, inflammation, migration, invasion, and angiogenesis of HG-induced hRMECs. Besides, the correlation between miR-6720-5p and hsa_circ_0000047/CYB5R2 was confirmed by luciferase assay and Pearson correlation analysis.Results: hsa_circ_0000047 and CYB5R2 were downregulated in DR, whereas miR-6720-5p was upregulated in DR. Cell functional experiments showed that hsa_circ_0000047 overexpression restrained viability, inflammation, migration, invasion, and angiogenesis of HG-induced hRMECs. Regarding mechanism, hsa_circ_0000047 could sponge miR-6720-5p to regulate CYB5R2 expression in hRMECs. Additionally, CYB5R2 knockdown reversed the effects of hsa_circ_0000047 overexpression on HG-induced hRMECs.Conclusion: Our study revealed that hsa_circ_0000047 alleviated inflammation and angiogenesis in HG-induced hRMECs by targeting the miR-6720-5p/CYB5R2 axis, which may be a novel biomarker for DR therapy.

Indoxyl sulfate induces retinal microvascular injury via COX-2/PGE2 activation in diabetic retinopathy

BACKGROUND

Diabetic retinopathy (DR), the principal cause of acquired blindness among the working-age population, is the most frequent microvascular complication of diabetes. Although metabolic disorders are hypothesized to play a role in its pathogenesis, the underlying mechanism remains largely elusive.

METHODS

To elucidate the mechanism, we initially compared metabolite profiles of vitreous fluid between 23 patients with DR and 12 non-diabetic controls using liquid chromatography/tandem mass spectrometry, identifying the distinct metabolite indoxyl sulfate (IS). Subsequently, streptozotocin (STZ)-induced diabetic and IS-injected rat models were established to examine the effects of IS on retinal microvasculature. RNA sequencing was conducted to identify potential regulatory mechanisms in IS-treated human retinal endothelial cells (HREC). Finally, target gene knockdown in HREC and treatment of IS-injected rats with inhibitors (targeting IS production or downstream regulators) were employed to elucidate the detailed mechanisms and identify therapeutic targets for DR.

RESULTS

Metabolomics identified 172 significantly altered metabolites in the vitreous humor of diabetics, including the dysregulated tryptophan metabolite indoxyl sulfate (IS). IS was observed to breach the blood-retinal barrier and accumulate in the intraocular fluid of diabetic rats. Both in vivo and in vitro experiments indicated that elevated levels of IS induced endothelial apoptosis and disrupted cell junctions. RNA sequencing pinpointed prostaglandin E2 (PGE2) synthetase-cyclooxygenase 2 (COX-2) as a potential target of IS. Validation experiments demonstrated that IS enhanced COX-2 expression, which subsequently increased PGE2 secretion by promoting transcription factor EGR1 binding to COX-2 DNA following entry into cells via organic anion transporting polypeptides (OATP2B1). Furthermore, inhibition of COX-2 in vivo or silencing EGR1/OATP2B1 in HREC mitigated IS-induced microcapillary damage and the activation of COX-2/PGE2.

CONCLUSION

Our study demonstrated that indoxyl sulfate (IS), a uremic toxin originating from the gut microbiota product indole, increased significantly and contributed to retinal microvascular damage in diabetic retinopathy (DR). Mechanistically, IS impaired retinal microvascular integrity by inducing the expression of COX-2 and the production of PGE2. Consequently, targeting the gut microbiota or the PGE2 pathway may offer effective therapeutic strategies for the treatment of DR.

Preoperative Intravitreal Conbercept Injection Reduced Both Angiogenic and Inflammatory Cytokines in Patients With Proliferative Diabetic Retinopathy

Aims: To investigate the impact of intravitreal injection of conbercept, a recombinant fusion protein with decoy receptors for the vascular endothelial growth factor (VEGF) family, on intraocular concentrations of angiogenic and inflammatory mediators in patients with proliferative diabetic retinopathy (PDR), analyzed its potential impact on surgical outcomes. Methods: Forty eyes from 40 patients with PDR were included in this prospective study. Patients received intravitreal injection of conbercept followed by vitrectomy or phacovitrectomy in 1 week. Aqueous humor samples were collected before and 1 week after the conbercept injection. The concentrations of angiogenic and inflammatory cytokines and chemokines were measured by flow cytometry. Follow-up clinical data were collected and analyzed. Results: Intravitreal conbercept injection significantly decreased aqueous concentrations of VEGF (325.5 (baseline) versus 22.3 pg/mL (postinjection), p < 0.0001), PlGF (39.5 versus 24.5 pg/mL, p < 0.0001), and PDGF-A (54.1 versus 47.0 pg/mL, p = 0.0016), while no impact on bFGF levels. For inflammatory mediators, the concentration of TNF-α (0.79 versus 0.45 pg/mL, p = 0.0004) and IL-8 (180.6 versus 86 pg/mL, p < 0.0001) were decreased, while IL-6 (184.1 versus 333.7 pg/mL, p = 0.0003) and IL-10 (1.1 versus 1.5 pg/mL, p = 0.0032) were increased. No significant changes in IFN-γ or MCP-1 were detected. Three months after surgery, the mean best-corrected visual acuity improved from a baseline of 1.8 ± 0.1 logMAR to 0.7 ± 0.1 logMAR (p < 0.0001), with 36 eyes (90%) achieving an improvement of visual function. Conclusions: Intravitreal conbercept injection presents dual effects of antiangiogenesis and anti-inflammation and can be served as an adjuvant treatment to vitrectomy for PDR patients.

TNFα and IL-8 vitreous concentrations variations with two antidiabetic therapies in patients with proliferative diabetic retinopathy: an observational study

BACKGROUND

Antidiabetic therapies are effective, but could indirectly modify the inflammatory response in the ocular microenvironment; therefore, a study was developed to evaluate the inflammatory cytokine profile in the vitreous humor of diabetic patients with retinopathy under treatment with antidiabetic drugs.

METHODS

Observational, comparative, retrospective, cross-sectional study. Interleukins 1β, 6, 8, 10, and tumor necrosis factor-alpha (TNFα) were evaluated in the vitreous humor obtained from patients with type 2 diabetes mellitus, proliferative diabetic retinopathy, and concomitant retinal detachment or vitreous hemorrhage, and who were already on antidiabetic treatment with insulin or metformin + glibenclamide. The quantification analysis of each cytokine was performed by the cytometric bead array (CBA) technique; medians and interquartile ranges were obtained, and the results were compared between groups using the Mann-Whitney U test, where a p-value < 0.05 was considered significant.

RESULTS

Thirty-eight samples; quantification of TNFα concentrations was higher in the group of patients administered insulin, while interleukin-8 was lower; in the metformin + glibenclamide combination therapy group, it occurred inversely. In the stratified analysis, the highest concentrations of interleukin-8 and TNFα occurred in patients with vitreous hemorrhage; however, the only statistical difference existed in patients with retinal detachment, whose TNFα concentration in the combined therapy group was the lowest value found (53.50 (33.03-86.66), p = 0.03). Interleukins 1β, 6, and 10 were not detected.

CONCLUSION

Interleukin-8 and TNFα concentrations are opposite between treatment groups; this change is more accentuated in patients with proliferative diabetic retinopathy and vitreous hemorrhage, where the highest concentrations of both cytokines are found, although only TNFα have statistical difference.

Severity of Disorganization of Retinal Layers and Visual Function Impairment in Diabetic Retinopathy

PURPOSE

To evaluate best-corrected visual acuity (BCVA), retina sensitivity (RS), and fixation impairment by microperimetry (MP) due to the presence and severity of disorganization of retinal inner and outer layers (DRIL/DROL) and ischemia in OCT/OCT angiography (OCTA) in diabetic retinopathy (DR).

DESIGN

Retrospective case-control study.

SUBJECTS

Seventy-six eyes (65 patients) with DR were analyzed. Major exclusion criteria were: center-involving diabetic macular edema (DME), significant media opacity, nondiabetic macular pathology, and active proliferative DR. Patients with DRIL and DROL within central 3 mm were enrolled as cases. Patients with DR and no retina disorganization were considered as controls.

METHODS

A detailed grading of MP and OCT/OCTA images using Image J software, and specific Image Manipulation Program was applied to colocalize the presence of retina disorganization and RS. Best-corrected visual acuity and RS were correlated with the disorganization of retina layers' characteristics and grading (grade 1-DRIL; grade 2-DROL; grade 3-DROL plus, with involvement of the ellipsoid zone). The same procedure of colocalization was applied to the vascular layers on OCTA using MATLAB.

MAIN OUTCOME MEASURES

Correlation between BCVA and MP parameters with disorganization of retina layers grading and OCTA parameters.

RESULTS

Best-corrected visual acuity, mean RS within 1 mm and central 3 mm (overall RS [oRS]), perfusion density, vessel density, and geometric perfusion deficit in intermediate and deep capillary plexuses were lower in cases versus controls (P < 0.001). Mean RS within 1 mm (21.4 decibels [dB] ± 2.4 vs. 13.8 dB ± 5.4, P = 0.002), oRS (22.0 dB ± 2.1 vs. 14.4 dB ± 4.6, P < 0.001), and BCVA (76.1 ± 7.4 vs. 61.2 ± 20.4 ETDRS letters; P = 0.02), had a significant decrease from grade 1 to grade 3 retina disorganization. Choriocapillaris flow voids (CC-FVs) increased from grade 1 to grade 3 (DROL plus) (P = 0.004). Overall retina sensitivity and CC-FV were identified as significant predictors of retina disorganization grade with an adjusted coefficient of determination, R2 = 0.45. Cases had more dense scotomas (P = 0.03) than controls with a positive correlation between the worsening of fixation stability and the severity of DRIL/DROL (P = 0.04).

CONCLUSIONS

Microperimetry and BCVA documented a reduction in visual function in patients with DR and disorganization of retina layers at different grades, with greater functional impairment when outer retina layers and photoreceptors are involved. The severity of retina disorganization and the presence of ischemia could serve as a potential biomarker of functional impairment.

FINANCIAL DISCLOSURES

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

Diabetes, Diabetic Retinopathy, and Inflammatory Disorders

This review summarizes the impact of systemic and ocular inflammatory disorders on diabetes mellitus (DM) and diabetic retinopathy (DR). Local inflammation is a key pathology in diabetic retinopathy (DR) and is also an evolving target for clinical therapy. The legacy effects of local inflammation at the intracellular level make DR a persistent self-driven vicious process. Ocular inflammation is accompanied as well as incited by systemic inflammation due to diabetes mellitus (DM) itself. Over the years, a multitude of studies have evaluated the impact of systemic inflammatory disorders (SIDs, like rheumatoid arthritis, lupus, psoriasis, etc.) and anti-inflammatory drugs prescribed for managing them on manifestations of DM. Recent studies have indicated increased insulin resistance to be a result of chronic inflammation, and the anti-inflammatory drugs to have a protective effect towards DM. Very few studies have evaluated the impact of SIDs on DR. Furthermore, the evidence from these studies is conflicting, and while local anti-inflammatory therapy has shown a lot of clinical potential for use in DR, the results of systemic anti-inflammatory therapies have been inconsistent. The impact of local ocular inflammation due to uveitis on DR is a crucial aspect that has not been evaluated well at present. Initial pre-clinical studies and small-sized clinical reports have shown a strong and positive relationship between the presence of uveitis and the severity of DR as well as its progression, while larger cross-sectional patient surveys have refuted the same. The long term impact of ocular inflammation due to uveitis on DR needs to be studied while adjusting for confounders.

Complement Factor C1q Mediates Vascular Endothelial Dysfunction in STZ-Induced Diabetic Mice

Diabetes is a significant global public health issue with implications for vascular endothelial cells (ECs) dysfunction and the subsequent development and advancement of diabetes complications. This study aims to compare the cellular and molecular properties of the aorta in normal and streptozotocin (STZ)-induced diabetic mice, with a focus on elucidating potential mechanism underlying EC dysfunction. Here, we performed a single-cell RNA sequencing survey of 32,573 cells from the aorta of normal and STZ-induced diabetic mice. We found a compendium of 10 distinct cell types, mainly ECs, smooth muscle cells, fibroblast, pericyte, immune cells, and stromal cells. As the diabetes condition progressed, we observed a subpopulation of aortic ECs that exhibited significantly elevated expression of complement (C) molecule C1qa compared with their healthy counterparts. This increased expression of C1qa was found to induce reactive oxygen species (ROS) production, facilitate EC migration and increased permeability, and impair the vasodilation within the aortic segment of mice. Furthermore, AAV-Tie2-shRNA-C1qa was administered into diabetic mice by tail vein injection, showing that inhibition of C1qa in the endothelium led to a reduction in ROS production, decreased vascular permeability, and improved vasodilation. Collectively, these findings highlight the crucial involvement of C1qa in endothelial dysfunction associated with diabetes.

ARTICLE HIGHLIGHTS

Photobiomodulation in Ophthalmology: A Comprehensive Review of Bench-to-Bedside Research and Clinical Integration

Photobiomodulation (PBM), also known as low-level laser therapy, is an emerging therapeutic modality in ophthalmology, attracting increasing interest for its potential to manage a variety of ocular conditions. PBM employs low-energy light within the red and near-infrared spectrum to penetrate biological tissues, where it interacts with cellular chromophores. This interaction is believed to enhance mitochondrial function, boost adenosine triphosphate (ATP) production, and reduce oxidative stress, leading to improved cellular repair and tissue regeneration. Recent bench research has demonstrated PBM's efficacy in cellular and animal models, showing its ability to modulate inflammatory processes and promote healing in retinal and corneal diseases. For instance, in retinal models, PBM has been observed to reduce apoptosis and support cell survival under stress conditions. Similarly, studies in corneal models suggest that PBM can accelerate wound healing and reduce scarring. Clinical trials further corroborate these findings, revealing that PBM can enhance treatment outcomes in several ocular diseases, including age-related macular degeneration, diabetic retinopathy, and dry eye disease. Patients undergoing PBM have reported improvements in visual acuity, reduced retinal inflammation, and better tear film stability, highlighting its potential as an adjunctive therapy. This review also explores the integration of PBM into clinical practice, discussing current treatment protocols, safety considerations, and the latest advancements in PBM technology. By offering a holistic overview, the review aims to provide clinicians and researchers with valuable insights into PBM's role in modern ophthalmic care, emphasizing its potential to enhance treatment strategies and improve patient outcomes.

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.

Therapeutic potential of flavopiridol in diabetic retinopathy: Targeting DDX58

Diabetic retinopathy (DR), a common complication of diabetes, is characterized by inflammation and neovascularization, and is intricately regulated by the ubiquitin-proteasome system (UPS). Despite advancements, identifying ubiquitin-related genes and drugs specifically targeting DR remains a significant challenge. In this study, bioinformatics analyses and the Connectivity Map (CMAP) database were utilized to explore the therapeutic potential of genes and drugs for DR. Through these methodologies, flavopiridol was identified as a promising therapeutic candidate. To evaluate flavopiridol's therapeutic potential in DR, an in vitro model using Human Umbilical Vein Endothelial Cells (HUVECs) induced by high glucose (HG) conditions was established. Additionally, in vivo models using mice with streptozotocin (STZ)-induced DR and oxygen-induced retinopathy (OIR) were employed. The current study reveals that flavopiridol possesses robust anti-inflammatory and anti-neovascularization properties. To further elucidate the molecular mechanisms of flavopiridol, experimental validation and molecular docking techniques were employed. These efforts identified DDX58 as a predictive target for flavopiridol. Notably, our research demonstrated that flavopiridol modulates the DDX58/NLRP3 signaling pathway, thereby exerting its therapeutic effects in suppressing inflammation and neovascularization in DR. This study unveils groundbreaking therapeutic agents and innovative targets for DR, and establishes a progressive theoretical framework for the application of ubiquitin-related therapies in DR.