Retinal microglia initiate neuroinflammation in ocular autoimmunity.

Autoimmune uveitis is a sight-threatening ocular inflammatory condition in which the retina and uveal tissues become a target of autoreactive immune cells. While microglia have been studied extensively in autoimmune uveitis, their exact function remains uncertain. The objective of the current study was to determine whether resident microglia are necessary and sufficient to initiate and amplify retinal inflammation in autoimmune uveitis. In this study, we clearly demonstrate that microglia are essential for initiating infiltration of immune cells utilizing a murine model of experimental autoimmune uveoretinitis (EAU) and the recently identified microglia-specific marker P2ry12. Initiating disease is the primary function of microglia in EAU, since eliminating microglia during the later stages of EAU had little effect, indicating that the function of circulating leukocytes is to amplify and sustain destructive inflammation once microglia have triggered disease. In the absence of microglia, uveitis does not develop, since leukocytes cannot gain entry through the blood-retinal barrier, illustrating that microglia play a critical role in regulating infiltration of inflammatory cells into the retina.

Microglia inhibit photoreceptor cell death and regulate immune cell infiltration in response to retinal detachment.

Retinal detachment (RD) is a sight-threatening complication common in many highly prevalent retinal disorders. RD rapidly leads to photoreceptor cell death beginning within 12 h following detachment. In patients with sustained RD, progressive visual decline due to photoreceptor cell death is common, leading to significant and permanent loss of vision. Microglia are the resident immune cells of the central nervous system, including the retina, and function in the homeostatic maintenance of the neuro-retinal microenvironment. It is known that microglia become activated and change their morphology in retinal diseases. However, the function of activated microglia in RD is incompletely understood, in part because of the lack of microglia-specific markers. Here, using the newly identified microglia marker P2ry12 and microglial depletion strategies, we demonstrate that retinal microglia are rapidly activated in response to RD and migrate into the injured area within 24 h post-RD, where they closely associate with infiltrating macrophages, a population distinct from microglia. Once in the injured photoreceptor layer, activated microglia can be observed to contain autofluorescence within their cell bodies, suggesting they function to phagocytose injured or dying photoreceptors. Depletion of retinal microglia results in increased disease severity and inhibition of macrophage infiltration, suggesting that microglia are involved in regulating neuroinflammation in the retina. Our work identifies that microglia mediate photoreceptor survival in RD and suggests that this effect may be due to microglial regulation of immune cells and photoreceptor phagocytosis.

Cytochrome P450 monooxygenase lipid metabolites are significant second messengers in the resolution of choroidal neovascularization.

Age-related macular degeneration (AMD) is the most common cause of blindness for individuals age 50 and above in the developed world. Abnormal growth of choroidal blood vessels, or choroidal neovascularization (CNV), is a hallmark of the neovascular (wet) form of advanced AMD and leads to significant vision loss. A growing body of evidence supports a strong link between neovascular disease and inflammation. Metabolites of long-chain polyunsaturated fatty acids derived from the cytochrome P450 (CYP) monooxygenase pathway serve as vital second messengers that regulate a number of hormones and growth factors involved in inflammation and vascular function. Using transgenic mice with altered CYP lipid biosynthetic pathways in a mouse model of laser-induced CNV, we characterized the role of these lipid metabolites in regulating neovascular disease. We discovered that the CYP-derived lipid metabolites epoxydocosapentaenoic acids (EDPs) and epoxyeicosatetraenoic acids (EEQs) are vital in dampening CNV severity. Specifically, overexpression of the monooxygenase CYP2C8 or genetic ablation or inhibition of the soluble epoxide hydrolase (sEH) enzyme led to increased levels of EDP and EEQ with attenuated CNV development. In contrast, when we promoted the degradation of these CYP-derived metabolites by transgenic overexpression of sEH, the protective effect against CNV was lost. We found that these molecules work in part through their ability to regulate the expression of key leukocyte adhesion molecules, on both leukocytes and endothelial cells, thereby mediating leukocyte recruitment. These results suggest that CYP lipid signaling molecules and their regulators are potential therapeutic targets in neovascular diseases.

Aqueous immune mediators in malignant uveal melanomas in comparison to benign pigmented intraocular tumors.

BACKGROUND: To examine the usefulness of measuring immune mediators in aqueous humor samples for differentiating malignant uveal melanoma from benign pigmented intraocular tumors. METHODS: Thirteen eyes of 13 patients with uveal melanoma were studied, and 13 eyes of 13 patients with benign pigmented intraocular tumors served as controls. Undiluted samples of aqueous humor were collected, and a cytometric bead array was used to determine the aqueous humor concentrations of 35 immune mediators comprising 14 interleukins (IL), interferon-γ, interferon-γ-inducible protein-10, monocyte chemoattractant protein (MCP)-1, macrophage inflammatory protein (MIP)-1α, MIP-1ß, regulated on activation normal T cell expressed and secreted, monokine induced by interferon-γ, basic fibroblast growth factor, Fas ligand, granzyme A, granzyme B, eotaxin, interferon-inducible T-cell alpha chemoattractant, fractalkine, granulocyte macrophage colony-stimulating factor, granulocyte colony-stimulating factor, vascular endothelial growth factor, angiogenin, tumor necrosis factor-α, lymphotoxin-α, and CD40L. RESULTS: Aqueous humor levels of angiogenin, IL-8, and MCP-1 were significantly higher in eyes with malignant melanoma than in those with benign tumors (p < 0.05). CONCLUSIONS: Angiogenin, IL-8, and MCP-1 levels in aqueous humor may be potential markers for distinguishing malignant uveal melanoma from benign pigmented intraocular tumors, and may be a useful adjunct to histomorphology, diagnostic imaging, and other biomarkers for the diagnosis and appropriate clinical management of malignant uveal melanoma.

Clinical Profile of Anti-Myelin Oligodendrocyte Glycoprotein Antibody Seropositive Cases of Optic Neuritis.

We have studied the clinical picture of anti-aquaporin antibody (AQP4-Ab)- and anti-myelin oligodendrocyte glycoprotein antibody (MOG-Ab)-positive optic neuritis. However, optic neuritis associated with MOG-Abs has not been elucidated using new methods such as cell-based assay. Hence, we conducted a comprehensive investigation on its clinical profile. Serum samples from 70 patients (17 males and 53 females, mean age 43.1 years) with optic neuritis were tested for MOG-Abs by cell-based assay. In MOG-Ab seropositive patients, the disease type, recurrence status, and visual function outcome were analysed. Among 70 patients, 18 were MOG-Ab seropositive. The 18 patients comprised 2 with chronic relapsing inflammatory optic neuropathy, 2 with AQP4-Ab seropositive optic neuritis (neuromyelitis optica), 12 with idiopathic optic neuritis, and 2 with optic neuritis associated with multiple sclerosis. Excluding two cases that were also AQP4-Ab seropositive, MOG-Ab seropositive cases had relatively favourable visual acuity outcome (although not significantly different from seronegative cases) but had significant residual visual field deficit (p = 0.0015). Furthermore, the number of relapses of optic neuritis per year was significantly greater in MOG-Ab seropositive cases than in seronegative cases (0.82 vs. 0.40; p = 0.0005). MOG-Abs may contribute to the heterogeneous clinical picture of optic neuritis, and although visual acuity outcome is favourable, there is a tendency of residual visual field deficit and a possibility of repeated relapses.

Profile of intraocular immune mediators in patients with age-related macular degeneration and the effect of intravitreal bevacizumab injection.

PURPOSE: To measure intraocular cytokine levels in patients with exudative age-related macular degeneration and analyze changes in the cytokine profile 2 days after intravitreal bevacizumab injection. METHODS: This prospective case-control study enrolled 37 patients (37 eyes) with age-related macular degeneration including polypoidal choroidal vasculopathy. Twenty-eight age-matched patients (28 eyes) who underwent cataract surgery were used as controls. Undiluted aqueous humor samples were collected after intravitreal bevacizumab injection. Two days after intravitreal bevacizumab injection, cataract surgery was performed and undiluted aqueous humor samples were collected at the beginning of surgery (10 eyes). Twenty-three cytokines were measured using flow cytometry. P values were corrected in multiple comparisons using the conservative Bonferroni-Holm method. The level of significance was set at 0.0022 (0.05/23). RESULTS: At baseline, aqueous humor levels of vascular endothelial growth factor, angiogenin, interferon gamma-inducible protein (IP)-10, macrophage inflammatory protein (MIP)-1ß, monokine induced by interferon γ (Mig), and monocyte chemotactic protein (MCP)-1 were significantly higher in the age-related macular degeneration group than in the control group (P < 0.0022). The result of exploratory multivariate analysis showed that elevated angiogenin level was an important factor that discriminates the two groups (P = 0.0004). Two days after intravitreal bevacizumab injection, vascular endothelial growth factor levels tended to be reduced (P = 0.049), whereas interleukin (IL)-6 and IL-8 levels increased significantly (P < 0.0022). CONCLUSION: Vascular endothelial growth factor and also angiogenin, IP-10, MCP-1, MIP-1ß, and Mig may be related to the pathogenesis of age-related macular degeneration. Intravitreal bevacizumab injection increases inflammatory cytokine levels, suggesting the induction of an inflammatory process.

A case of herpes zoster uveitis with severe hyphema.

BACKGROUND: Uveitis sometimes causes hyphema, but severe hyphema as a complication following herpes zoster uveitis has rarely been reported. We report a rare case of zoster sine herpete with unusually severe hyphema. CASE PRESENTATION: A 41-year-old Japanese female developed hyphema filling almost one-half of the depth of the anterior chamber after a two-week history of unilateral anterior uveitis. Hyphema persisted for four weeks while sectorial iris atrophy became gradually apparent. Systemic prednisolone and valaciclovir resulted in prompt resolution of uveitis and hyphema. Serum anti-varicella zoster virus (VZV) IgG measured by enzyme immunoassay was 116 at presentation and decreased to 20.3 four month later. In addition, the antibody level in aqueous humor was almost 10-fold higher than that in serum examined 9 months after presentation. Because there was no skin lesion, this case was diagnosed as zoster sine herpete. The patient underwent cataract operation due to secondary cataract. The final visual acuity in decimal notation was 1.0, but complications such as severe iris atrophy, wide anterior synechiae, corneal opacity, and decrease in corneal endothelial cell count remained. CONCLUSION: Zoster sine herpete is an important differential diagnosis in a case of acute anterior uveitis with severe hyphema, although such cases are quite rare. Measurement of anti-VZV IgG levels by enzyme immunoassay in aqueous humor and serum would be useful in the diagnosis of VZV reactivation. Prompt diagnosis and administration of corticosteroids and anti-herpes virus medication may improve the outcome.

Retinal microglia exacerbate uveitis by functioning as local antigen-presenting cells.

Autoimmune uveitis is a major cause of blindness in the working-age population of developed countries. Experimental autoimmune uveitis (EAU) depends on activation of interphotoreceptor retinoid-binding protein (IRBP) specific CD4 + effector T cells that migrate systemically and infiltrate into the retina. Following systemic induction of retinal antigen-specific T cells, the development of EAU can be broken down into three phases: early phase when inflammatory cells begin to infiltrate the retina, amplification phase, and peak phase. Although studied extensively, the function of local antigen-presenting cells (APCs) within the retina remains unclear. Two potential types of APCs are present during uveitis, resident microglia and infiltrating CD11c + dendritic cells (DCs). MHC class II (MHC II) is expressed within the retina on both CD11c + DCs and microglia during the amplification phase of EAU. Therefore, we used microglia specific (P2RY12 and TMEM119) and CD11c + DC specific MHC II knockout mice to study the function of APCs within the retina using the conventional and adoptive transfer methods of inducing EAU. Microglia were essential during all phases of EAU development: the early phase when microglia were MHC Il negative, and amplification and peak phases when microglia were MHC II positive. Unexpectedly, retinal infiltrating MHC Il + CD11c + DCs were present within the retina but their antigen-presenting function was not required for all phases of uveitis. Our data indicate microglia are the critical APCs within the retina and an important therapeutic target that can prevent and/or diminish uveitis even in the presence of circulating IRBP-specific CD4 + effector T cells.

Peroxisome proliferator-activated receptor-γ agonist pioglitazone suppresses experimental autoimmune uveitis.

Peroxisome proliferator-activated receptor (PPAR)-γ agonists are clinically used as anti-diabetes agents. Recent research has discovered that an anti-inflammatory effect of PPAR agonist may have the potential to treat autoimmune disease. In the present study, we investigated the anti-inflammatory effects of PPAR-γ agonist, pioglitazone, on murine model of endogenous uveitis. Experimental autoimmune uveoretinitis (EAU) was induced by immunizing C57BL/6 mice with human interphotoreceptor retinoid binding protein-derived peptide (1-20). Pioglitazone or vehicle was injected intravenously from day -1 (whole phase treatment) or day 8 (effector phase study) until day 20. Severity of EAU was assessed clinically and pathologically on day 21. Immunological status was assessed by measuring intraocular inflammatory factors, and activation and regulatory markers of CD4(+) T cells in draining lymph nodes (LNs). Treatment with pioglitazone suppressed both whole-phase and effector-phase of EAU. In effector-phase treatment, intraocular concentrations of TNF-α and IL-6 were significantly suppressed, and CD4(+)Foxp3(+) regulatory T cells and CD4(+)CD62L(high) naïve T cells increased in draining LNs, although there were no differences in CD4(+)CD44(high) effector T cells and IL-17 producing CD4(+) T cells between pioglitazone- and vehicle-treated mice. Administration of pioglitazone before and after the onset of EAU significantly reduced disease severity. The present results suggest that pioglitazone may be a novel therapeutic agent for endogenous uveitis.

Correlation of complement fragment C5a with inflammatory cytokines in the vitreous of patients with proliferative diabetic retinopathy.

PURPOSE: To determine the vitreous concentration of complement fragment C5a in patients with proliferative diabetic retinopathy (PDR) and the relation between C5a and inflammatory cytokines including vascular endothelial growth factor (VEGF) and monocyte chemotactic protein-1 (MCP-1). METHODS: Vitreous samples were obtained at the time of vitrectomy from 12 eyes of 11 PDR patients and from 11 eyes of 11 patients without diabetes with macular disease (controls). Vitreous and serum concentrations of human C5a, VEGF, and MCP-1 were quantified using FACS Caliber flow cytometer. RESULTS: Vitreous concentration of C5a increased significantly in patients with PDR [median (range): 928.7 (46.6 to 3,319.4) pg/ml] compared with controls [58.7 (22.2 to 1,432.4) pg/ml; p < 0.01]. In PDR patients, vitreous concentration of C5a correlated significantly with those of VEGF (p < 0.05) and MCP-1 (p < 0.05). CONCLUSIONS: Our results suggest that C5a may play an important role in the pathogenesis of PDR and work in concert with inflammatory cytokines such as VEGF and MCP-1 in pathological angiogenesis.

Effects of soluble CD14 and cytokine levels on diabetic macular edema and visual acuity.

PURPOSE: The pathogenesis of diabetic retinopathy has been suggested to be associated with ocular inflammation. Macrophages and monocytes that infiltrate the eye are known to express CD14. After shedding from the membrane-bound CD14, soluble CD14 (sCD14) is released, which could potentially activate inflammatory signaling. In this study, the authors investigated ocular fluid and serum levels of vascular endothelial growth factor (VEGF), sCD14, and other inflammatory cytokines in patients with diabetic macular edema (DME). Furthermore, the authors determined any potential correlation between these factors and visual acuity. METHODS: Vitreous fluid, aqueous humor, and serum samples from 14 eyes with DME and 24 control eyes were investigated. Soluble CD14, interleukin 8, interferon-inducible protein 10, monocyte chemotactic protein 1, monokine induced by interferon γ, and VEGF were measured simultaneously by FACSCalibur flow cytometer. Visual acuity was measured in all patients with DME before surgery, with the assessors being blinded to the patients' diagnoses. RESULTS: All factors were significantly elevated in vitreous fluid of DME eyes. Soluble CD14 and VEGF levels in vitreous fluid and aqueous humor were significantly higher in patients with DME than in nondiabetic controls (P < 0.05). In patients with DME, vitreous and aqueous humor concentrations of sCD14 correlated significantly. In these patients, vitreous fluid concentration of sCD14 correlated significantly with that of VEGF or interleukin 8 or monocyte chemotactic protein 1. In addition, there was a significant positive correlation between preoperative visual acuity and intraocular sCD14 concentrations. CONCLUSION: Soluble CD14 may act as key regulator of VEGF production and contribute to the pathogenesis of diabetic retinopathy.

Costimulatory molecule expression on human uveal melanoma cells: functional analysis of CD40 and B7-H1.

Costimulatory molecules play important roles in regulating T cell function in tumor immunity. In this study, we investigated costimulatory molecule expression on human uveal melanoma cells (a primary culture, and OCM-1, OMM-1 and 92-1 cell lines) and assessed the functional roles of selected costimulatory molecules. Uveal melanoma cells were incubated in the presence or absence of IFN-γ and expression of costimulatory molecules on the cells was measured by flow cytometry. The costimulatory effect of B7-H1-expressing uveal melanoma cells on cytokine production by purified T cells was studied in uveal melanoma/T cell co-culture experiments using a blocking anti-B7-H1 monoclonal antibody (mAb). The functional role of CD40-mediated interactions in modifying immune responses to uveal melanoma cells was assessed in vitro using recombinant human CD40 ligand (rhCD40L). MHC class I and B7-H1 were consistently detected and further upregulated by IFN-γ stimulation in all human uveal melanoma cell cultures. CD40 was consistently detected and further upregulated by IFN-γ stimulation in primary culture, OCM-1, and OMM-1 but not 92-1. IL-2 production from purified CD3(+) T cells co-stimulated with IFN-γ-treated uveal melanoma cells was significantly enhanced by the addition of anti-B7-H1 mAb. Treatment of primary culture, OCM-1, or OMM-1 with rhCD40L induced or enhanced secretion of chemokines IL-8, MCP-1, IP-10 and RANTES. These results suggest that the expression of B7-H1 on IFN-γ-treated uveal melanoma cells contributes to suppression of T cells by decreasing IL-2 production. In contrast, CD40 expressed on uveal melanoma cells plays an important role in augmenting anti-tumor immunity by stimulating chemokine production. The dual effects of CD40 and B7-H1 may contribute to positive or negative regulation of anti-tumor immune responses to human uveal melanoma.

Increases of vitreous monocyte chemotactic protein 1 and interleukin 8 levels in patients with concurrent hypertension and diabetic retinopathy.

PURPOSE: To investigate whether concurrent hypertension affects vitreous cytokine levels in diabetic retinopathy. METHODS: Vitreous samples from 41 patients with diabetic retinopathy with or without concurrent hypertension, who underwent vitrectomy, were collected. Vitreous cytokine concentrations were simultaneously measured using flow cytometry. Patients were stratified according to hypertension or other clinical conditions, and the differences in vitreous levels of monocyte chemotactic protein 1, interleukin 8, vascular endothelial growth factor, interferon-inducible protein 10, and monokine induced by interferon gamma were examined. RESULTS: Vitreous levels of monocyte chemotactic protein 1 and interleukin 8 were significantly (P < 0.05) higher in hypertensive patients than in nonhypertensive patients and were significantly (P < 0.05) higher in active diabetic retinopathy than in inactive diabetic retinopathy. Vitreous levels of vascular endothelial growth factor, interferon-inducible protein 10, and monokine induced by interferon gamma were not affected by the coexistence of hypertension. In multivariate models, active diabetic retinopathy (P = 0.004 and P = 0.007), systolic blood pressure (P = 0.039 and P = 0.041), and hypertension (P = 0.032 and P = 0.035) were significant and independent predictors for increased vitreous monocyte chemotactic protein 1 and interleukin 8 levels. CONCLUSION: Both monocyte chemotactic protein 1 and interleukin 8 levels were elevated in the vitreous of patients with diabetic retinopathy and concurrent hypertension. These findings may help to explain the epidemiologic and clinical evidence that systemic hypertension exacerbates diabetic retinopathy.

CD47 Deficiency Ameliorates Ocular Autoimmune Inflammation.

Autoimmune uveitis is a sight-threatening ocular inflammatory condition in which the retina and uveal tissues become a target of autoreactive immune cells. The CD47 is a ubiquitously expressed transmembrane protein which plays multiple roles in fundamental cellular functions including phagocytosis, proliferation, and adhesion. Signal regulatory protein alpha (SIRPα), one of the CD47 ligands, is predominantly expressed in myeloid lineage cells such as dendritic cells (DCs) or macrophages, and CD47-SIRPα signaling pathway is implicated in the development of autoimmune diseases. Our current study demonstrates how CD47 depletion is effective in the prevention of experimental autoimmune uveitis (EAU), an animal model of human autoimmune uveitis, in animals deficient of CD47 (CD47-/- ). Systemic suppression of SIRPα+ DCs in animals deficient in CD47 resulted in the inability of autoreactive CD4+ T cells to develop, which is crucial to induction of EAU. Of interest, retinal microglia, the resident immune cell of the retina, express SIRPα, however these cells were not operative in EAU suppression in response to CD47 depletion. These results identify CD47 as a significant regulator in the development of SIRPα+ DCs that is vital to disease induction in EAU.

Human uveal melanoma cells inhibit the immunostimulatory function of dendritic cells.

Dendritic cells are critical for the induction of anti-tumor immunity. Recent studies suggest that some tumors may avoid immune destruction by inhibiting dendritic cell function. In this study, we investigated the effects of uveal melanoma on human dendritic cell phenotype and functions including surface antigen expression, cytokine production, and T cell activation. Dendritic cells were generated in the presence of GM-CSF and IL-4 from peripheral blood mononuclear cells of healthy donors. On day 5 of culture, dendritic cells were co-cultured with human uveal melanoma cells for 24 h, and then purified using magnetic beads. The maturation of dendritic cells was induced by TNF-α and the phenotype of dendritic cells was analyzed by flow cytometry. The expression of dendritic cell markers and antigen presenting cell markers decreased when dendritic cells were co-cultured with uveal melanoma cells. Moreover, co-culture with uveal melanoma cells led to apoptosis of dendritic cells as shown by 1.5-fold increase in surface phosphatidylserine. Also, dendritic cells co-cultured with uveal melanoma showed diminished ability to produce IL-12 and IL-10. Finally, dendritic cells co-cultured with uveal melanoma inhibited the proliferation of allogeneic T cells in mixed lymphocyte reaction. These findings suggest a mechanism by which uveal melanoma escape immune destruction and have significant implications for tumor-pulsed dendritic cell vaccines for the treatment of uveal melanoma.

Correlation of vascular endothelial growth factor with chemokines in the vitreous in diabetic retinopathy.

PURPOSE: The purpose of this study was to simultaneously measure the concentrations of multiple cytokines, including vascular endothelial growth factor, in the vitreous of patients with diabetic retinopathy and to examine their relation with clinical findings. METHODS: Vitreous samples from 46 eyes with diabetic retinopathy and 19 eyes with nondiabetic macular disease (controls) were used. Nine cytokines were simultaneously measured using a FACSCalibur flow cytometer. RESULTS: Vascular endothelial growth factor, interleukin-8, monocyte chemotactic protein-1, interferon-inducible protein-10, and monokine induced by interferon-gamma were detected in the vitreous samples, and the concentrations were significantly (P < 0.001) higher in patients with diabetic retinopathy compared with control subjects. Vascular endothelial growth factor, interleukin-8, monocyte chemotactic protein-1, and monokine induced by interferon-gamma concentrations were significantly (P < 0.05) higher in active retinopathy than in inactive retinopathy. Furthermore, a significant (P < 0.01) positive correlation was observed between vascular endothelial growth factor concentration and interleukin-8, monocyte chemotactic protein-1, interferon-inducible protein-10, or monokine induced by interferon-gamma concentration in the vitreous. CONCLUSION: Vascular endothelial growth factor, interleukin-8, monocyte chemotactic protein-1, interferon-inducible protein-10, and monokine induced by interferon-gamma were expressed at high levels locally in ocular tissues in diabetic retinopathy, and these cytokines may form a network and interact to impact the pathogenesis of the disease.

[Pars plana vitrectomy in patients with acute retinal necrosis syndrome: surgical results in 52 patients].

PURPOSE: To analyze results of pars plana vitrectomy for acute retinal necrosis (ARN) syndrome. METHODS: We reviewed the records of 52 eyes with ARN syndrome who underwent pars plana vitrectomy at the Tokyo Medical University Hospital from 1989 to 2007. The mean age was 50.1 +/- 10.2 years and the mean follow-up duration was 75.3 months. The causative virus was herpes simplex virus in 7 cases and varicella zoster virus in 45 cases. In all cases, treatment with acyclovir and corticosteroids was started from presentation. During the follow-up period, vitrectomy was done in patients who developed retinal detachment, and in those who developed posterior vitreous detachment exerting marked traction on the retina, even though retinal detachment had not occurred. In these cases, preoperative and postoperative visual acuities were compared and reoperation, retinal detachment preventive surgery and age-stratified visual prognosis after vitrectomy were analyzed. RESULTS: Visual acuity was improved by 2 lines or more in 13 eyes (25.0%), remained unchanged in 16 eyes (30.8%), and deteriorated by 2 lines or more in 23 eyes (44.2%). Thirty-seven of 52 eyes (71.2%) required re-operation. No significant differences were detected when the patients were stratified according to whether they were treated either with or without combined use of silicon oil, or according to whether they were treated either with or without prophylactic surgery for retinal detachment, as well as by age of vitrectomy. A combination of lens extraction, silicon oil and encircling sclera buckling procedure was associated with a significantly higher frequency of final visual acuity. CONCLUSION: Despite the advances in vitrectomy achieved today, the visual prognosis of acute retinal necrosis remains unsatisfactory. The present study found no significant improvement in the prognostic relevance of prophylactic vitrectomy. Improvement in pharmacotherapy may help improve the prognosis. Further prospective large-scale studies to compare other treatment modalities are also required.

Human iris pigment epithelial cells suppress T-cell activation via direct cell contact.

The purposes of the present study were to investigate whether cultured human iris pigment epithelial (hIPE) cells acquire the ability to modify T-cell activation, and if so, to identify the mechanism. Human IPE cells were prepared from patients who underwent glaucoma surgery, and were cultured in RPMI 1640 medium containing 10% fetal calf serum for 4-7 days. Expression of MHC molecules and co-stimulatory molecules on cultured hIPE cells either unstimulated or stimulated with IFN-gamma was examined by FACS. In addition, peripheral blood T cells were incubated with cultured hIPE cells prepared from the same patients and anti-CD3 antibody in a transwell culture system, or in the presence of anti-PD-L1 and PD-L2 antibodies, and T cell proliferation was assessed by [3H]-thymidine incorporation. The hIPE cells inhibited anti-CD3-driven T-cell activation but the inhibition was diminished when tested in the transwell culture system, indicating that a contact-dependent mechanism is important in the immunoregulatory roles of hIPE. Although cultured hIPE cells expressed Class I and PD-L1 but not Class II or PD-L2, all these molecules were observed on hIPE cells cultured in the presence of IFN-gamma. Blocking antibodies against both PD-L1 and PD-L2 reduced the immunoregulatory activity of hIPE cells. Our data indicates that cultured hIPE cells inhibit T-cell activation by T-cell receptor ligation, which is mediated by cell-to-cell contact in part via the PD-L1 and PD-L2 pathways.

Mouse model of ocular hypertension with retinal ganglion cell degeneration.

OBJECTIVES: Ocular hypertension is a primary risk factor for glaucoma and results in retinal ganglion cell (RGC) degeneration. Current animal models of glaucoma lack severe RGC cell death as seen in glaucoma, making assessment of physiological mediators of cell death difficult. We developed a modified mouse model of ocular hypertension whereby long-lasting elevation of intraocular pressure (IOP) is achieved, resulting in significant reproducible damage to RGCs. RESULTS: In this model, microbeads are mixed with hyaluronic acid and injected into the anterior chamber of C57BL/6J mice. The hyaluronic acid allows for a gradual release of microbeads, resulting in sustained blockage of Schlemm's canal. IOP elevation was bimodal during the course of the model's progression. The first peak occurred 1 hours after beads injection, with an IOP value of 44.69 ± 6.00 mmHg, and the second peak occurred 6-12 days post-induction, with an IOP value of 34.91 ± 5.21 mmHg. RGC damage was most severe in the peripheral retina, with a loss of 64.1% compared to that of untreated eyes, while the midperiphery exhibited a 32.4% loss, 4 weeks following disease induction. CONCLUSIONS: These results suggest that sustained IOP elevation causes more RGC damage in the periphery than in the midperiphery of the retina. This model yields significant and reproducible RGC degeneration.

Proteomic surveillance of retinal autoantigens in endogenous uveitis: implication of esterase D and brain-type creatine kinase as novel autoantigens.

PURPOSE: Various retinal proteins are newly exposed to immune system in a process of tissue destructive endogenous uveitis. Some of such proteins could be autoantigens that extend the ocular inflammation in human endogenous uveitis. In this study, we aimed to investigate the possibility of such spreading of autoantigens in endogenous uveoretinitis using a proteomic approach. METHODS: Experimental autoimmune uveoretinitis (EAU) was induced in mice by inoculation with a peptide consisting of amino acids 1-20 (GPTHLFQPSLVLDMAKVLLP) of interphotoreceptor retinoid binding protein (IRBP). Six weeks after immunization, the presence of autoantibodies against the retinal proteins in mice with EAU were examined by two-dimensional electrophoresis followed by western blotting (2D-WB). Retinal proteins targeted by the autoantibodies were identified by mass spectrometry (MS) and their autoantigenicity in patients with endogenous uveitis, such as Behcet's disease (BD, n=36), Vogt-Koyanagi-Harada disease (VKH, n=16), and sarcoidosis (n=17) were examined by enzyme-linked immunosorbent assay. RESULTS: Six new candidate autoantigens, which were detected in mice with EAU using 2D-WD were identified by MS as beta-actin, esterase D (EsteD), tubulin beta-2, brain-type creatine kinase (BB-CK), voltage-dependent anion-selective channel protein, and aspartate aminotransferase. Among the patients with endogenous uveitis, 25% of BD and 25% of VKH patients were positive for anti-EsteD antibody, and 25% of VKH and 38.4% of sarcoidosis patients were positive for anti-BB-CK antibody. CONCLUSIONS: Autoantibodies to EsteD and BB-CK produced in EAU-induced mice were also detected in some endogenous uveitis patients, suggesting that these proteins might be autoantigens spreading in a process of endogenous uveoretinitis.