scholarly journals RORγt Inhibitor-SR1001 Halts Retinal Inflammation, Capillary Degeneration, and the Progression of Diabetic Retinopathy

2020 ◽  
Vol 21 (10) ◽  
pp. 3547
Author(s):  
Thomas E. Zapadka ◽  
Sarah I. Lindstrom ◽  
Brooklyn E. Taylor ◽  
Chieh A. Lee ◽  
Jie Tang ◽  
...  
Keyword(s):  
Diabetic Retinopathy ◽  
Microvascular Disease ◽  
Orphan Receptor ◽  
Vascular Pathology ◽  
Diabetic Mice ◽  
Molecule Inhibitor ◽  
Working Age ◽  
Endothelial Cell Death ◽  
Retinal Inflammation ◽  
Capillary Degeneration

Diabetic retinopathy is a diabetes-mediated retinal microvascular disease that is the leading cause of blindness in the working-age population worldwide. Interleukin (IL)-17A is an inflammatory cytokine that has been previously shown to play a pivotal role in the promotion and progression of diabetic retinopathy. Retinoic acid-related orphan receptor gammaT (RORγt) is a ligand-dependent transcription factor that mediates IL-17A production. However, the role of RORγt in diabetes-mediated retinal inflammation and capillary degeneration, as well as its potential therapeutic attributes for diabetic retinopathy has not yet been determined. In the current study, we examined retinal inflammation and vascular pathology in streptozotocin-induced diabetic mice. We found RORγt expressing cells in the retinal vasculature of diabetic mice. Further, diabetes-mediated retinal inflammation, oxidative stress, and retinal endothelial cell death were all significantly lower in RORγt−/− mice. Finally, when a RORγt small molecule inhibitor (SR1001) was subcutaneously injected into diabetic mice, retinal inflammation and capillary degeneration were ameliorated. These findings establish a pathologic role for RORγt in the onset of diabetic retinopathy and identify a potentially novel therapeutic for this blinding disease.

scholarly journals Diabetic Retinopathy: The Role of Mitochondria in the Neural Retina and Microvascular Disease

Antioxidants ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 905 ◽  
Author(s):  
David J. Miller ◽  
M. Ariel Cascio ◽  
Mariana G. Rosca
Keyword(s):  
Diabetic Retinopathy ◽  
Vision Loss ◽  
Neurovascular Unit ◽  
Microvascular Disease ◽  
Retinal Disease ◽  
Neural Retina ◽  
Vascular Pathology ◽  
Future Research ◽  
Substrate Selection ◽  
Working Age

Diabetic retinopathy (DR), a common chronic complication of diabetes mellitus and the leading cause of vision loss in the working-age population, is clinically defined as a microvascular disease that involves damage of the retinal capillaries with secondary visual impairment. While its clinical diagnosis is based on vascular pathology, DR is associated with early abnormalities in the electroretinogram, indicating alterations of the neural retina and impaired visual signaling. The pathogenesis of DR is complex and likely involves the simultaneous dysregulation of multiple metabolic and signaling pathways through the retinal neurovascular unit. There is evidence that microvascular disease in DR is caused in part by altered energetic metabolism in the neural retina and specifically from signals originating in the photoreceptors. In this review, we discuss the main pathogenic mechanisms that link alterations in neural retina bioenergetics with vascular regression in DR. We focus specifically on the recent developments related to alterations in mitochondrial metabolism including energetic substrate selection, mitochondrial function, oxidation-reduction (redox) imbalance, and oxidative stress, and critically discuss the mechanisms of these changes and their consequences on retinal function. We also acknowledge implications for emerging therapeutic approaches and future research directions to find novel mitochondria-targeted therapeutic strategies to correct bioenergetics in diabetes. We conclude that retinal bioenergetics is affected in the early stages of diabetes with consequences beyond changes in ATP content, and that maintaining mitochondrial integrity may alleviate retinal disease.

scholarly journals Retinal Inflammation, Oxidative Stress, and Vascular Impairment Is Ablated in Diabetic Mice Receiving XMD8-92 Treatment

2021 ◽  
Vol 12 ◽  
Author(s):  
Scott J. Howell ◽  
Chieh A. Lee ◽  
Julia C. Batoki ◽  
Thomas E. Zapadka ◽  
Sarah I. Lindstrom ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Diabetic Retinopathy ◽  
New Drugs ◽  
Type I ◽  
Type Ii ◽  
Diabetic Mice ◽  
Junction Protein ◽  
Type Ii Diabetics ◽  
Retinal Inflammation

The global number of diabetics continues to rise annually. As diabetes progresses, almost all of Type I and more than half of Type II diabetics develop diabetic retinopathy. Diabetic retinopathy is a microvascular disease of the retina, and is the leading cause of blindness in the working-age population worldwide. With such a significant health impact, new drugs are required to halt the blinding threat posed by this visual disorder. The cause of diabetic retinopathy is multifactorial, and an optimal therapeutic would halt inflammation, cease photoreceptor cell dysfunction, and ablate vascular impairment. XMD8-92 is a small molecule inhibitor that blocks inflammatory activity downstream of ERK5 (extracellular signal-related kinase 5) and BRD4 (bromodomain 4). ERK5 elicits inflammation, is increased in Type II diabetics, and plays a pathologic role in diabetic nephropathy, while BRD4 induces retinal inflammation and plays a role in retinal degeneration. Further, we provide evidence that suggests both pERK5 and BRD4 expression are increased in the retinas of our STZ (streptozotocin)-induced diabetic mice. Taken together, we hypothesized that XMD8-92 would be a good therapeutic candidate for diabetic retinopathy, and tested XMD8-92 in a murine model of diabetic retinopathy. In the current study, we developed an in vivo treatment regimen by administering one 100 μL subcutaneous injection of saline containing 20 μM of XMD8-92 weekly, to STZ-induced diabetic mice. XMD8-92 treatments significantly decreased diabetes-mediated retinal inflammation, VEGF production, and oxidative stress. Further, XMD8-92 halted the degradation of ZO-1 (zonula occludens-1), which is a tight junction protein associated with vascular permeability in the retina. Finally, XMD8-92 treatment ablated diabetes-mediated vascular leakage and capillary degeneration, which are the clinical hallmarks of non-proliferative diabetic retinopathy. Taken together, this study provides strong evidence that XMD8-92 could be a potentially novel therapeutic for diabetic retinopathy.

scholarly journals Attenuating Diabetic Vascular and Neuronal Defects by Targeting P2rx7

2019 ◽  
Vol 20 (9) ◽  
pp. 2101 ◽  
Author(s):  
Sofia Pavlou ◽  
Josy Augustine ◽  
Rónán Cunning ◽  
Kevin Harkin ◽  
Alan W. Stitt ◽  
...  
Keyword(s):  
Diabetic Retinopathy ◽  
Therapeutic Potential ◽  
Neuronal Degeneration ◽  
Amacrine Cells ◽  
Oscillatory Potentials ◽  
Transcriptase Inhibitor ◽  
Vascular Pathology ◽  
Vascular Lesions ◽  
Diabetic Mice ◽  
New Treatments

Retinal vascular and neuronal degeneration are established pathological features of diabetic retinopathy. Data suggest that defects in the neuroglial network precede the clinically recognisable vascular lesions in the retina. Therefore, new treatments that target early-onset neurodegeneration would be expected to have great value in preventing the early stages of diabetic retinopathy. Here, we show that the nucleoside reverse transcriptase inhibitor lamivudine (3TC), a newly discovered P2rx7 inhibitor, can attenuate progression of both neuronal and vascular pathology in diabetic retinopathy. We found that the expression of P2rx7 was increased in the murine retina as early as one month following diabetes induction. Compared to non-diabetic controls, diabetic mice treated with 3TC were protected against the formation of acellular capillaries in the retina. This occurred concomitantly with a maintenance in neuroglial function, as shown by improved a- and b-wave amplitude, as well as oscillatory potentials. An improvement in the number of GABAergic amacrine cells and the synaptophysin-positive area was also observed in the inner retina of 3TC-treated diabetic mice. Our data suggest that 3TC has therapeutic potential since it can target both neuronal and vascular defects caused by diabetes.

scholarly journals Loss of CD40 attenuates experimental diabetes-induced retinal inflammation but does not protect mice from electroretinogram defects

2017 ◽  
Vol 34 ◽  
Author(s):  
IVY S. SAMUELS ◽  
JOSE-ANDRES C. PORTILLO ◽  
YANLING MIAO ◽  
TIMOTHY S. KERN ◽  
CARLOS S. SUBAUSTE
Keyword(s):  
Diabetic Retinopathy ◽  
Experimental Diabetes ◽  
Low Grade ◽  
Retinal Dysfunction ◽  
Diabetic Retina ◽  
Inflammatory Processes ◽  
Retinal Inflammation ◽  
Capillary Degeneration ◽  
Inflammatory Molecules ◽  
Low Grade Inflammation

AbstractChronic low grade inflammation is considered to contribute to the development of experimental diabetic retinopathy (DR). We recently demonstrated that lack of CD40 in mice ameliorates the upregulation of inflammatory molecules in the diabetic retina and prevented capillary degeneration, a hallmark of experimental diabetic retinopathy. Herein, we investigated the contribution of CD40 to diabetes-induced reductions in retinal function via the electroretinogram (ERG) to determine if inflammation plays a role in the development of ERG defects associated with diabetes. We demonstrate that diabetic CD40−/− mice are not protected from reduction to the ERG b-wave despite failing to upregulate inflammatory molecules in the retina. Our data therefore supports the hypothesis that retinal dysfunction found in diabetics occurs independent of the induction of inflammatory processes.

scholarly journals Aryl Hydrocarbon Receptor Agonist VAF347 Impedes Retinal Pathogenesis in Diabetic Mice

2021 ◽  
Vol 22 (9) ◽  
pp. 4335
Author(s):  
Thomas E. Zapadka ◽  
Sarah I. Lindstrom ◽  
Julia C. Batoki ◽  
Chieh A. Lee ◽  
Brooklyn E. Taylor ◽  
...  
Keyword(s):  
Diabetic Retinopathy ◽  
Aryl Hydrocarbon Receptor ◽  
Proliferative Diabetic Retinopathy ◽  
Proinflammatory Cytokine ◽  
Primary Source ◽  
Dendritic Cell Maturation ◽  
Diabetic Mice ◽  
Aryl Hydrocarbon ◽  
Aryl Hydrocarbon Receptor Agonist ◽  
Capillary Degeneration

Diabetic retinopathy is the leading cause of blindness in the working-age population worldwide. Although the cause of diabetic retinopathy is multifactorial, IL-17A is a prevalent inflammatory cytokine involved in the promotion of diabetes-mediated retinal inflammation and the progression of diabetic retinopathy. The primary source of IL-17A is Th17 cells, which are T helper cells that have been differentiated by dendritic cells in a proinflammatory cytokine environment. Aryl hydrocarbon receptor (AhR) is a ligand-dependent transcription factor that can manipulate dendritic cell maturation, halt the production of IL-6 (a proinflammatory cytokine), and suppress Th17 cell differentiation. In the current study, we examined the efficacy of an AhR agonist, VAF347, as a potential therapeutic for the onset of non-proliferative diabetic retinopathy in streptozotocin (STZ)-induced diabetic C57BL/6 mice. We determined that diabetes-mediated leukostasis, oxidative stress, and inflammation in the retina of STZ-diabetic mice were all significantly lower when treated with the AhR agonist VAF347. Furthermore, when VAF347 was subcutaneously injected into STZ-diabetic mice, retinal capillary degeneration was ameliorated, which is the hallmark of non-proliferative diabetic retinopathy in this diabetes murine model. Collectively, these findings provide evidence that the AhR agonist VAF347 could be a potentially novel therapeutic for non-proliferative diabetic retinopathy.

scholarly journals Neurovascular unit in diabetic retinopathy: pathophysiological roles and potential therapeutical targets

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Shen Nian ◽  
Amy C. Y. Lo ◽  
Yajing Mi ◽  
Kai Ren ◽  
Di Yang
Keyword(s):  
Diabetic Retinopathy ◽  
Early Stage ◽  
Neurovascular Unit ◽  
Microvascular Disease ◽  
Industrialized Countries ◽  
Novel Treatments ◽  
Microvascular Changes ◽  
Working Age ◽  
Retinal Neurodegeneration ◽  
The Common

AbstractDiabetic retinopathy (DR), one of the common complications of diabetes, is the leading cause of visual loss in working-age individuals in many industrialized countries. It has been traditionally regarded as a purely microvascular disease in the retina. However, an increasing number of studies have shown that DR is a complex neurovascular disorder that affects not only vascular structure but also neural tissue of the retina. Deterioration of neural retina could precede microvascular abnormalities in the DR, leading to microvascular changes. Furthermore, disruption of interactions among neurons, vascular cells, glia and local immune cells, which collectively form the neurovascular unit, is considered to be associated with the progression of DR early on in the disease. Therefore, it makes sense to develop new therapeutic strategies to prevent or reverse retinal neurodegeneration, neuroinflammation and impaired cell-cell interactions of the neurovascular unit in early stage DR. Here, we present current perspectives on the pathophysiology of DR as a neurovascular disease, especially at the early stage. Potential novel treatments for preventing or reversing neurovascular injuries in DR are discussed as well.

scholarly journals Reduced Levels of Drp1 Protect against Development of Retinal Vascular Lesions in Diabetic Retinopathy

Cells ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1379
Author(s):  
Dongjoon Kim ◽  
Hiromi Sesaki ◽  
Sayon Roy
Keyword(s):  
Diabetic Retinopathy ◽  
Cell Loss ◽  
Vascular Lesions ◽  
Protective Effects ◽  
Diabetic Mice ◽  
Wild Type ◽  
Apoptotic Genes ◽  
Retinal Vascular Lesions ◽  
Acellular Capillaries ◽  
Pericyte Loss

High glucose (HG)-induced Drp1 overexpression contributes to mitochondrial dysfunction and promotes apoptosis in retinal endothelial cells. However, it is unknown whether inhibiting Drp1 overexpression protects against the development of retinal vascular cell loss in diabetes. To investigate whether reduced Drp1 level is protective against diabetes-induced retinal vascular lesions, four groups of mice: wild type (WT) control mice, streptozotocin (STZ)-induced diabetic mice, Drp1+/− mice, and STZ-induced diabetic Drp1+/− mice were examined after 16 weeks of diabetes. Western Blot analysis indicated a significant increase in Drp1 expression in the diabetic retinas compared to those of WT mice; retinas of diabetic Drp1+/− mice showed reduced Drp1 level compared to those of diabetic mice. A significant increase in the number of acellular capillaries (AC) and pericyte loss (PL) was observed in the retinas of diabetic mice compared to those of the WT control mice. Importantly, a significant decrease in the number of AC and PL was observed in retinas of diabetic Drp1+/− mice compared to those of diabetic mice concomitant with increased expression of pro-apoptotic genes, Bax, cleaved PARP, and increased cleaved caspase-3 activity. Preventing diabetes-induced Drp1 overexpression may have protective effects against the development of vascular lesions, characteristic of diabetic retinopathy.

Retinal microglia polarization in diabetic retinopathy

2021 ◽  
Vol 38 ◽  
Author(s):  
Xin Li ◽  
Zi-Wei Yu ◽  
Hui-Yao Li ◽  
Yue Yuan ◽  
Xin-Yuan Gao ◽  
...  
Keyword(s):  
Central Nervous System ◽  
Diabetic Retinopathy ◽  
Cytokine Production ◽  
Immune Cell ◽  
Microvascular Disease ◽  
Retinal Diseases ◽  
Microglia Polarization ◽  
Retinal Microglia ◽  
The Central Nervous System ◽  
Retinal Neurodegeneration

Abstract Microglia, the main immune cell of the central nervous system (CNS), categorized into M1-like phenotype and M2-like phenotype, play important roles in phagocytosis, cell migration, antigen presentation, and cytokine production. As a part of CNS, retinal microglial cells (RMC) play an important role in retinal diseases. Diabetic retinopathy (DR) is one of the most common complications of diabetes. Recent studies have demonstrated that DR is not only a microvascular disease but also retinal neurodegeneration. RMC was regarded as a central role in neurodegeneration and neuroinflammation. Therefore, in this review, we will discuss RMC polarization and its possible regulatory factors in early DR, which will provide new targets and insights for early intervention of DR.

scholarly journals Bone Morphogenetic Proteins and Diabetic Retinopathy

Biomolecules ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 593
Author(s):  
Khaled Elmasry ◽  
Samar Habib ◽  
Mohamed Moustafa ◽  
Mohamed Al-Shabrawey
Keyword(s):  
Diabetic Retinopathy ◽  
Bone Morphogenetic Proteins ◽  
Potential Role ◽  
Microvascular Dysfunction ◽  
Cardiovascular Complications ◽  
Bmp Signaling ◽  
Age Related Macular Degeneration ◽  
Age Related ◽  
Retinal Inflammation ◽  
Underlying Mechanisms

Bone morphogenetic proteins (BMPs) play an important role in bone formation and repair. Recent studies underscored their essential role in the normal development of several organs and vascular homeostasis in health and diseases. Elevated levels of BMPs have been linked to the development of cardiovascular complications of diabetes mellitus. However, their particular role in the pathogenesis of microvascular dysfunction associated with diabetic retinopathy (DR) is still under-investigated. Accumulated evidence from our and others’ studies suggests the involvement of BMP signaling in retinal inflammation, hyperpermeability and pathological neovascularization in DR and age-related macular degeneration (AMD). Therefore, targeting BMP signaling in diabetes is proposed as a potential therapeutic strategy to halt the development of microvascular dysfunction in retinal diseases, particularly in DR. The goal of this review article is to discuss the biological functions of BMPs, their underlying mechanisms and their potential role in the pathogenesis of DR in particular.

scholarly journals A Systematic Review of Carotenoids in the Management of Diabetic Retinopathy

Nutrients ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 2441
Author(s):  
Drake W. Lem ◽  
Dennis L. Gierhart ◽  
Pinakin Gunvant Davey
Keyword(s):  
Diabetic Retinopathy ◽  
Vision Loss ◽  
Therapeutic Potential ◽  
Microvascular Disease ◽  
Age Related Macular Degeneration ◽  
Cell Degeneration ◽  
Neuroprotective Effects ◽  
Age Related ◽  
Induced Changes ◽  
Dietary Carotenoid

Diabetic retinopathy, which was primarily regarded as a microvascular disease, is the leading cause of irreversible blindness worldwide. With obesity at epidemic proportions, diabetes-related ocular problems are exponentially increasing in the developed world. Oxidative stress due to hyperglycemic states and its associated inflammation is one of the pathological mechanisms which leads to depletion of endogenous antioxidants in retina in a diabetic patient. This contributes to a cascade of events that finally leads to retinal neurodegeneration and irreversible vision loss. The xanthophylls lutein and zeaxanthin are known to promote retinal health, improve visual function in retinal diseases such as age-related macular degeneration that has oxidative damage central in its etiopathogenesis. Thus, it can be hypothesized that dietary supplements with xanthophylls that are potent antioxidants may regenerate the compromised antioxidant capacity as a consequence of the diabetic state, therefore ultimately promoting retinal health and visual improvement. We performed a comprehensive literature review of the National Library of Medicine and Web of Science databases, resulting in 341 publications meeting search criteria, of which, 18 were found eligible for inclusion in this review. Lutein and zeaxanthin demonstrated significant protection against capillary cell degeneration and hyperglycemia-induced changes in retinal vasculature. Observational studies indicate that depletion of xanthophyll carotenoids in the macula may represent a novel feature of DR, specifically in patients with type 2 or poorly managed type 1 diabetes. Meanwhile, early interventional trials with dietary carotenoid supplementation show promise in improving their levels in serum and macular pigments concomitant with benefits in visual performance. These findings provide a strong molecular basis and a line of evidence that suggests carotenoid vitamin therapy may offer enhanced neuroprotective effects with therapeutic potential to function as an adjunct nutraceutical strategy for management of diabetic retinopathy.

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