Down-expression of the NLRP3 inflammasome delays the progression of diabetic retinopathy.

The investigation aimed to evaluate the effects of Mcc950, an inhibitor of the NLRP3 inflammasome, on diabetic retinopathy (DR) mice. The general physiological condition of each group of mice was recorded. Retinal blood vessels were stained for observation of the density of blood vessels, and retinas were used for further morphological examination and fluorescent staining after the intravitreal injection of Mcc950. Mcc950 partially reversed hyperglycemia-induced vascular damage and had reduced histological changes compared to DR mice. IL-1ß production in mice retinas in the diabetic model (DM) group increased, but pretreatment with Mcc950 significantly reversed these changes. Additionally, Mcc950 engineered reduced FITC dextran extravasation and vascular leakage. Therefore, it played an apparent protective role in DR and could be a new treatment strategy for DR.

Label-free imaging of immune cell dynamics in the living retina using adaptive optics.

Our recent work characterized the movement of single blood cells within the retinal vasculature (Joseph et al. 2019) using adaptive optics ophthalmoscopy. Here, we apply this technique to the context of acute inflammation and discover both infiltrating and tissue-resident immune cells to be visible without any labeling in the living mouse retina using near-infrared light alone. Intravital imaging of immune cells can be negatively impacted by surgical manipulation, exogenous dyes, transgenic manipulation and phototoxicity. These confounds are now overcome, using phase contrast and time-lapse videography to reveal the dynamic behavior of myeloid cells as they interact, extravasate and survey the mouse retina. Cellular motility and differential vascular responses were measured noninvasively and in vivo across hours to months at the same retinal location, from initiation to the resolution of inflammation. As comparable systems are already available for clinical research, this approach could be readily translated to human application.

Role of CD 20+ T cells and related cytokines in mediating retinal microvascular changes and ocular complications in chronic-plaque type psoriasis.

OBJECTIVE: To assess the role of CD3+ CD20+ CD4- CD8- double-negative (DN) or CD3+CD20+ CD4/CD8+ T cells and the related pro-inflammatory cytokines in the humor aqueous, in mediating retinal microvascular changes in patients with chronic plaque-type moderate to severe psoriasis. DESIGN: A total of 76 patients (57.6 ± 11.7 years) with chronic plaque-type psoriasis were initially evaluated. Nineteen patients (19 eyes) and 19 healthy volunteers (19 eyes) were subjected to dermatological evaluation with Psoriasis Area Severity Index (PASI) and the Dermatology life quality index (DLQI). Retinal images were processed using an automatized software. On the same day, a venous sample was collected and analyzed using multiparametric flow cytometry. Three out of 6 patients who presented cataract, consented to perform surgery with humor aqueous collection. The samples were analyzed using a Multi-Analyte ELISA kit for the simultaneous quantification of IL1α, IL1ß, IL2, IL4, IL6, IL8, IL10, IL12, IL17A, IFNγ, TNF-α, GMCSF. RESULTS: The CD3+CD4+/CD8+CD20+CD56- T cells expression was greater in the psoriatic patients (+73.9%, P < 0.001) compared to controls, but not the DN T cells (-8.2%, P = 0.30). Ocular complications were diagnosed in 61.1% of patients, microvascular parameters including artero-venous ratio (P = 0.04), subfoveal choriocapillaris/Sattler's layer, and choroidal thickness (CT, both P < 0.001) were significantly altered in psoriasis subgroup. The increased circulating levels of the CD3+CD4+/CD8+CD20+CD56- T cells were associated with thinning of subfoveal CT (P = 0.03) and Haller's layer (P = 0.01). Instead, the DN T cells presented an inverse relationship with disease duration (P = 0.02), DLQI score (P = 0.02), and the use of biological therapy (P = 0.05). The related cytokine patterns possibly modified in this cellular context have been investigated. No significant differences were observed in cytokines levels between psoriasis and controls, the most significant difference was detected on IL-6, without reaching statistical significance (fold change of 1.4, P = 0.13). CONCLUSION: Our findings demonstrated that CD20+ T cell subpopulation is highly represented in psoriasis regardless of the use of immunomodulatory therapies, and the diffuse microvascular alterations suggested possible endothelial damage as mainstream for the genesis of psoriatic-mediated complications as further supported by the comparable concentrations of cytokines, at least as humor aqueous content, with respect to healthy eyes.

Neutrophil extracellular traps target senescent vasculature for tissue remodeling in retinopathy.

In developed countries, the leading causes of blindness such as diabetic retinopathy are characterized by disorganized vasculature that can become fibrotic. Although many such pathological vessels often naturally regress and spare sight-threatening complications, the underlying mechanisms remain unknown. Here, we used orthogonal approaches in human patients with proliferative diabetic retinopathy and a mouse model of ischemic retinopathies to identify an unconventional role for neutrophils in vascular remodeling during late-stage sterile inflammation. Senescent vasculature released a secretome that attracted neutrophils and triggered the production of neutrophil extracellular traps (NETs). NETs ultimately cleared diseased endothelial cells and remodeled unhealthy vessels. Genetic or pharmacological inhibition of NETosis prevented the regression of senescent vessels and prolonged disease. Thus, clearance of senescent retinal blood vessels leads to reparative vascular remodeling.

STAT3 activation in circulating myeloid-derived cells contributes to retinal microvascular dysfunction in diabetes.

BACKGROUND: Leukostasis is a key patho-physiological event responsible for capillary occlusion in diabetic retinopathy. Circulating monocytes are the main cell type entrapped in retinal vessels in diabetes. In this study, we investigated the role of the signal transducer and activator of transcription 3 (STAT3) pathway in diabetes-induced immune cell activation and its contribution to retinal microvascular degeneration. METHODS: Forty-one patients with type 1 diabetes (T1D) [mild non-proliferative diabetic retinopathy (mNPDR) (n = 13), active proliferative DR (aPDR) (n = 14), inactive PDR (iPDR) (n = 14)] and 13 age- and gender-matched healthy controls were recruited to the study. C57BL/6 J WT mice, SOCS3fl/fl and LysMCre/+SOCS3fl/fl mice were rendered diabetic by Streptozotocin injection. The expression of the phosphorylated human and mouse STAT3 (pSTAT3), mouse LFA-1, CD62L, CD11b and MHC-II in circulating immune cells was evaluated by flow cytometry. The expression of suppressor of cytokine signalling 3 (SOCS3) was examined by real-time RT-PCR. Mouse plasma levels of cytokines were measured by Cytometric Beads Array assay. Retinal leukostasis was examined following FITC-Concanavalin A perfusion and acellular capillary was examined following Isolectin B4 and Collagen IV staining. RESULTS: Compared to healthy controls, the expression of pSTAT3 in circulating leukocytes was statistically significantly higher in mNPDR but not aPDR and was negatively correlated with diabetes duration. The expression of pSTAT3 and its inhibitor SOCS3 was also significantly increased in leukocytes from diabetic mice. Diabetic mice had higher plasma levels of IL6 and CCL2 compared with control mice. LysMCre/+SOCS3fl/fl mice and SOCS3fl/fl mice developed comparative levels of diabetes, but leukocyte activation, retinal leukostasis and number of acellular capillaries were statistically significantly increased in LysMCre/+SOCS3fl/fl diabetic mice. CONCLUSION: STAT3 activation in circulating immune cells appears to contribute to retinal microvascular degeneration and may be involved in DR initiation in T1D.

The CD40-ATP-P2X 7 Receptor Pathway: Cell to Cell Cross-Talk to Promote Inflammation and Programmed Cell Death of Endothelial Cells.

Extracellular adenosine 5'-triphosphate (ATP) functions not only as a neurotransmitter but is also released by non-excitable cells and mediates cell-cell communication involving glia. In pathological conditions, extracellular ATP released by astrocytes may act as a "danger" signal that activates microglia and promotes neuroinflammation. This review summarizes in vitro and in vivo studies that identified CD40 as a novel trigger of ATP release and purinergic-induced inflammation. The use of transgenic mice with expression of CD40 restricted to retinal Müller glia and a model of diabetic retinopathy (a disease where the CD40 pathway is activated) established that CD40 induces release of ATP in Müller glia and triggers in microglia/macrophages purinergic receptor-dependent inflammatory responses that drive the development of retinopathy. The CD40-ATP-P2X7 pathway not only amplifies inflammation but also induces death of retinal endothelial cells, an event key to the development of capillary degeneration and retinal ischemia. Taken together, CD40 expressed in non-hematopoietic cells is sufficient to mediate inflammation and tissue pathology as well as cause death of retinal endothelial cells. This process likely contributes to development of degenerate capillaries, a hallmark of diabetic and ischemic retinopathies. Blockade of signaling pathways downstream of CD40 operative in non-hematopoietic cells may offer a novel means of treating diabetic and ischemic retinopathies.

Retinal Cryo-sections, Whole-Mounts, and Hypotonic Isolated Vasculature Preparations for Immunohistochemical Visualization of Microvascular Pericytes.

Retinal pericytes play an important role in many diseases of the eye. Immunohistochemical staining techniques of retinal vessels and microvascular pericytes are central to ophthalmological research. It is vital to choose an appropriate method of visualizing the microvascular pericytes. We describe retinal microvascular pericyte immunohistochemical staining in cryo-sections, whole-mounts, and hypotonic isolated vasculature using antibodies for platelet-derived growth factor receptor ß (PDGFRß) and nerve/glial antigen 2 (NG2). This allows us to highlight advantages and shortcomings of each of the three tissue preparations for the visualization of the retinal microvascular pericytes. Cryo-sections provide transsectional visualization of all retinal layers but contain only a few occasional transverse cuts of the microvasculature. Whole-mount provides an overview of the entire retinal vasculature, but visualization of the microvasculature can be troublesome. Hypotonic isolation provides a method to visualize the entire retinal vasculature by the removal of neuronal cells, but this makes the tissue very fragile.

Endothelial Cell-Specific Inactivation of TSPAN12 (Tetraspanin 12) Reveals Pathological Consequences of Barrier Defects in an Otherwise Intact Vasculature.

Objective- Blood-CNS (central nervous system) barrier defects are implicated in retinopathies, neurodegenerative diseases, stroke, and epilepsy, yet, the pathological mechanisms downstream of barrier defects remain incompletely understood. Blood-retina barrier (BRB) formation and retinal angiogenesis require ß-catenin signaling induced by the ligand norrin (NDP [Norrie disease protein]), the receptor FZD4 (frizzled 4), coreceptor LRP5 (low-density lipoprotein receptor-like protein 5), and the tetraspanin TSPAN12 (tetraspanin 12). Impaired NDP/FZD4 signaling causes familial exudative vitreoretinopathy, which may lead to blindness. This study seeked to define cell type-specific functions of TSPAN12 in the retina. Approach and Results- A loxP-flanked Tspan12 allele was generated and recombined in endothelial cells using a tamoxifen-inducible Cdh5-CreERT2 driver. Resulting phenotypes were documented using confocal microscopy. RNA-Seq, histopathologic analysis, and electroretinogram were performed on retinas of aged mice. We show that TSPAN12 functions in endothelial cells to promote vascular morphogenesis and BRB formation in developing mice and BRB maintenance in adult mice. Early loss of TSPAN12 in endothelial cells causes lack of intraretinal capillaries and increased VE-cadherin (CDH5 [cadherin5 aka VE-cadherin]) expression, consistent with premature vascular quiescence. Late loss of TSPAN12 strongly impairs BRB maintenance without affecting vascular morphogenesis, pericyte coverage, or perfusion. Long-term BRB defects are associated with immunoglobulin extravasation, complement deposition, cystoid edema, and impaired b-wave in electroretinograms. RNA-sequencing reveals transcriptional responses to the perturbation of the BRB, including genes involved in vascular basement membrane alterations in diabetic retinopathy. Conclusions- This study establishes mice with late endothelial cell-specific loss of Tspan12 as a model to study pathological consequences of BRB impairment in an otherwise intact vasculature.

Plasma Exosomes Contribute to Microvascular Damage in Diabetic Retinopathy by Activating the Classical Complement Pathway.

Diabetic retinopathy (DR) is a microvascular complication of diabetes and is the leading cause of vision loss in working-age adults. Recent studies have implicated the complement system as a player in the development of vascular damage and progression of DR. However, the role and activation of the complement system in DR are not well understood. Exosomes, small vesicles that are secreted into the extracellular environment, have a cargo of complement proteins in plasma, suggesting that they can participate in causing the vascular damage associated with DR. We demonstrate that IgG-laden exosomes in plasma activate the classical complement pathway and that the quantity of these exosomes is increased in diabetes. Moreover, we show that a lack of IgG in exosomes in diabetic mice results in a reduction in retinal vascular damage. The results of this study demonstrate that complement activation by IgG-laden plasma exosomes could contribute to the development of DR.

The alternative complement pathway aids in vascular regression during the early stages of a murine model of proliferative retinopathy.

Proliferative retinopathic diseases often progress in 2 phases: initial regression of retinal vasculature (phase 1) followed by subsequent neovascularization (NV) (phase 2). The immune system has been shown to aid in vascular pruning in such retinopathies; however, little is known about the role of the alternative complement pathway in the initial vascular regression phase. Using a mouse model of oxygen-induced retinopathy (OIR), we observed that alternative complement pathway-deficient mice (Fb(-/-)) exhibited a mild decrease in vascular loss at postnatal day (P)8 compared with age- and strain-matched controls (P = 0.035). Laser capture microdissection was used to isolate the retinal blood vessels. Expression of the complement inhibitors Cd55 and Cd59 was significantly decreased in blood vessels isolated from hyperoxic retinas compared with those from normoxic control mice. Vegf expression was measured at P8 and found to be significantly lower in OIR mice than in normoxic control mice (P = 0.0048). Further examination of specific Vegf isoform expression revealed a significant decrease in Vegf120 (P = 0.00032) and Vegf188 (P = 0.0092). In conjunction with the major modulating effects of Vegf during early retinal vascular development, our data suggest a modest involvement of the alternative complement pathway in targeting vessels for regression in the initial vaso-obliteration stage of OIR.

Diabetic Retinopathy: Vascular and Inflammatory Disease.

Diabetic retinopathy (DR) is the leading cause of visual impairment in the working-age population of the Western world. The pathogenesis of DR is complex and several vascular, inflammatory, and neuronal mechanisms are involved. Inflammation mediates structural and molecular alterations associated with DR. However, the molecular mechanisms underlying the inflammatory pathways associated with DR are not completely characterized. Previous studies indicate that tissue hypoxia and dysregulation of immune responses associated with diabetes mellitus can induce increased expression of numerous vitreous mediators responsible for DR development. Thus, analysis of vitreous humor obtained from diabetic patients has made it possible to identify some of the mediators (cytokines, chemokines, and other factors) responsible for DR pathogenesis. Further studies are needed to better understand the relationship between inflammation and DR. Herein the main vitreous-related factors triggering the occurrence of retinal complication in diabetes are highlighted.

Silybin reduces obliterated retinal capillaries in experimental diabetic retinopathy in rats.

Silybin has been previously reported to possess anti-inflammatory properties, raising the possibility that it may reduce vascular damage in diabetic retinopathy. Present study was designed to investigate this potential effect of silybin and its underlying mechanisms in experimental diabetic retinopathy. Diabetes was induced with streptozotocin (STZ) plus high-fat diet in Sprague-Dawley rats, and silybin was administrated for 22 weeks after the induction of diabetes. Histochemical and immunofluorescence techniques were used to assess the obliterated retinal capillaries, leukostasis, and level of retinal intercellular adhesion molecule-1 (ICAM-1). Western blot was performed to quantitate the expression of retinal ICAM-1. Results showed that silybin treatment significantly prevented the development of obliterated retinal capillaries in diabetes, compared with vehicle treatment. In addition, leukostasis and level of the retinal ICAM-1 were found to decrease considerably in silybin-treated diabetic groups. In conclusion, these results indicate that silybin reduces obliterated retinal capillaries in experimental diabetes, and the recovered retinal vascular leukostasis and level of ICAM-1 at least partly contributes to the preventive effect of silybin.

Hyperglycemia induces Toll-like receptor-2 and -4 expression and activity in human microvascular retinal endothelial cells: implications for diabetic retinopathy.

Diabetic retinopathy (DR) causes visual impairment in working age adults and hyperglycemia-mediated inflammation is central in DR. Toll-like receptors (TLRs) play a key role in innate immune responses and inflammation. However, scanty data is available on their role in DR. Hence, in this study, we examined TLR2 and TLR4 mRNA and protein expression and activity in hyperglycemic human retinal endothelial cells (HMVRECs). HMVRECs were treated with hyperglycemia (HG) or euglycemia and mRNA and protein levels of TLR-2, TLR-4, MyD88, IRF3, and TRIF as well as NF-κB p65 activation were measured. IL-8, IL-1ß, TNF-α and MCP-1, ICAM-1, and VCAM-1 as well as monocyte adhesion to HMVRECs were also assayed. HG (25 mM) significantly induced TLR2 and TLR4 mRNA and protein in HMVRECs. It also increased both MyD88 and non-MyD88 pathways, nuclear factor-κB (NF-κB), biomediators, and monocyte adhesion. This inflammation was attenuated by TLR-4 or TLR-2 inhibition, and dual inhibition by a TLR inhibitory peptide as well as TLR2 and 4 siRNA. Additionally, antioxidant treatment reduced TLR-2 and TLR4 expression and downstream inflammatory markers. Collectively, our novel data suggest that hyperglycemia induces TLR-2 and TLR-4 activation and downstream signaling mediating increased inflammation possibly via reactive oxygen species (ROS) and could contribute to DR.

Angiogenesis mediated by toll-like receptor 4 in ischemic neural tissue.

OBJECTIVE: Activation of the immune system via toll-like receptors (TLRs) is implicated in atherosclerosis, microvascular complications, and angiogenesis. However, the involvement of TLRs in inflammation-associated angiogenesis in ischemic neural tissue has not been investigated. The goal of this study is to determine the role of TLR4 signaling in oxygen-induced neovascularization in retina, a neural tissue. METHODS AND RESULTS: In oxygen-induced retinopathy model, we found that retinal neovascularization was significantly attenuated in TLR4(-/-) mice. The further study revealed that the absence of TLR4 led to downregulation of proinflammatory factors in association with the attenuated activation of glia in the ischemic retina, which was also associated with reduced expression of high-mobility group box-1, an endogenous ligand for TLR4. The application of high-mobility group box-1 to the ischemic retina promoted the production of proinflammatory factors in wild-type but not TLR4(-/-) mice. High-mobility group box-1 treatment in vitro also significantly promoted the production of proinflammatory factors in retinal glial cells from wild-type mice, but much less from TLR4(-/-) mice. CONCLUSIONS: Our results suggest that the release of high-mobility group box-1 in ischemic neural tissue initiates TLR4-dependent responses that contribute to neovascularization. These findings represented a previously unrecognized effect of TLR4 on angiogenesis in association with the activation of glia in ischemic neural tissue.

Antibody-mediated retinal pericyte injury: implications for diabetic retinopathy.

PURPOSE: To test the hypothesis that autoantibodies against retinal pericytes could develop in diabetic retinopathy, and that these autoantibodies could induce retinal pericyte dysfunction/death via complement. METHODS: Human primary retinal pericytes cultured in media containing normal (5 mM) or high (30 mM) glucose concentrations were incubated with normal human sera in the presence of a retinal pericyte-reactive antibody, then their viability was assessed by a BCECF-based cytotoxicity assay, and their function was assessed by a T-cell proliferation assay. The pericytes were also analyzed by RT-PCR and flow cytometry to detect CD38, an established diabetes-associated cell surface autoantigen. The potential of the anti-CD38 antibodies in inducing pericyte cellular injury was evaluated using the same cytotoxicity assays. In addition, autoantibody-mediated cytotoxicity in mouse retinal pericytes sensitized by sera from mice with developing diabetic retinopathy or control normal mice were also studied. RESULTS: Retinal pericyte-reactive antibodies induced cellular damage by activating complement in the serum. The antibody-injured pericytes had reduced efficacy in inhibiting T cells. Hyperglycemic culture conditions rendered pericytes more susceptible to antibody-mediated attack. CD38 was expressed in retinal pericytes, and upregulated by TNF-α and IFN-γ, and anti-CD38 antibodies induced pericyte cytotoxicity. Retinal pericytes sensitized with sera from chronic diabetic mice suffered significantly augmented cytotoxicity compared with those sensitized with sera from the control mice. CONCLUSIONS: The autoantibody-initiated complement activation could be a mechanism underlying the loss of function, and eventually, death of retinal pericytes in diabetic patients, suggesting that inhibiting complement activation could be a novel therapeutic approach.

Crosstalk in the retinal neurovascular unit - lessons for the diabetic retina.

Diabetic retinopathy shares important features with neurodegenerative retinal diseases, including loss of ganglion cells and retinal thinning. The impact on vasoregression and subsequent ischemia-driven changes such as macular edema and proliferative retinopathy are not established. Studies using adult neurodegenerative animal models such as the transgenic TGR(CMV-PKD2(1/703)HA) rat imply early activation of the innate immunity system and the complement system as well as microglia playing a role in the damage of the retinal neurovascular unit.

Vascular cellular adhesion molecule-1 (VCAM-1) expression in mice retinal vessels is affected by both hyperglycemia and hyperlipidemia.

BACKGROUND: Inflammation has been proposed to be important in the pathogenesis of diabetic retinopathy. An early feature of inflammation is the release of cytokines leading to increased expression of endothelial activation markers such as vascular cellular adhesion molecule-1 (VCAM-1). Here we investigated the impact of diabetes and dyslipidemia on VCAM-1 expression in mouse retinal vessels, as well as the potential role of tumor necrosis factor-α (TNFα). METHODOLOGY/PRINCIPAL FINDINGS: Expression of VCAM-1 was examined by confocal immunofluorescence microscopy in vessels of wild type (wt), hyperlipidemic (ApoE(-/-)) and TNFα deficient (TNFα(-/-), ApoE(-/-)/TNFα(-/-)) mice. Eight weeks of streptozotocin-induced diabetes resulted in increased VCAM-1 in wt mice, predominantly in small vessels (<10 µm). Diabetic wt mice had higher total retinal TNFα, IL-6 and IL-1ß mRNA than controls; as well as higher soluble VCAM-1 (sVCAM-1) in plasma. Lack of TNFα increased higher basal VCAM-1 protein and sVCAM-1, but failed to up-regulate IL-6 and IL-1ß mRNA and VCAM-1 protein in response to diabetes. Basal VCAM-1 expression was higher in ApoE(-/-) than in wt mice and both VCAM-1 mRNA and protein levels were further increased by high fat diet. These changes correlated to plasma cholesterol, LDL- and HDL-cholesterol, but not to triglycerides levels. Diabetes, despite further increasing plasma cholesterol in ApoE(-/-) mice, had no effects on VCAM-1 protein expression or on sVCAM-1. However, it increased ICAM-1 mRNA expression in retinal vessels, which correlated to plasma triglycerides. CONCLUSIONS/SIGNIFICANCE: Hyperglycemia triggers an inflammatory response in the retina of normolipidemic mice and up-regulation of VCAM-1 in retinal vessels. Hypercholesterolemia effectively promotes VCAM-1 expression without evident stimulation of inflammation. Diabetes-induced endothelial activation in ApoE(-/-) mice seems driven by elevated plasma triglycerides but not by cholesterol. Results also suggest a complex role for TNFα in the regulation of VCAM-1 expression, being protective under basal conditions but pro-inflammatory in response to diabetes.

Targeting the kallikrein-kinin system as a new therapeutic approach to diabetic retinopathy.

Diabetic retinopathy (DR) is a major microvascular complication of diabetes mellitus that can lead to visual impairment and blindness. There is no approved pharmacological treatment for DR; however, laser therapy, steroids and anti-VEGF agents appear to provide some benefit. Hyperglycemia, advanced glycation end products, growth factors, and elevated levels of circulating and vitreous cytokines and chemokines can all trigger an inflammatory response of the retinal vasculature. Features of DR can include diabetic macular edema, microhemorrhage, loss of capillaries, development of avascular areas and the vitreo-retinal proliferation of neovessels. The kallikrein-kinin system (KKS) has long been recognized as a key player of inflammatory processes in various organs. Intravitreally administered recombinant plasma kallikrein has been demonstrated to produce retinal vascular leakage and hemorrhage, while both kinin B1 and B2 receptor agonists have induced retinal edema. Furthermore, kallikrein inhibitors and peptide-based B1 receptor antagonists could reduce or block retinal vascular permeability in diabetic rats. In a diabetic rat model, FOV-2304 (Fovea Pharmaceuticals SA), a non-peptide selective B1 receptor antagonist, consistently blocked retinal vascular permeability, inhibited leukocyte adhesion and abolished the retinal mRNA expression of several inflammatory mediators. Although additional studies are required to investigate the role of the KKS in early capillary loss and late-stage neovascularization processes, the blockade of the KKS is a promising therapeutic strategy for DR.

Comparison between stereo angiographic findings and histopathologic findings in endotoxin-induced uveitis.

PURPOSE: To carry out a three-dimensional analysis of uveitis using stereo angiography. MATERIALS AND METHODS: Endotoxin-induced uveitis was induced by injecting lipopolysaccharide into the rat footpad, and the findings of stereo angiography with a scanning laser ophthalmoscope were compared to histopathologic results. RESULTS: On day 2, multiple hyperfluorescent spots were observed by indocyanine green stereo angiography, which appeared to be in the superficial layer of the retina. Histopathologic findings showed infiltration of leukocytes into the corresponding area, which was the retinal nerve fiber layer. CONCLUSIONS: Stereo angiography was considered useful for three-dimensional analysis of uveitis lesions in the retina and choroid.