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.

Insulin inhibits inflammation-induced cone death in retinal detachment.

BACKGROUND: Rhegmatogenous retinal detachment (RD) involving the macula is a major cause of visual impairment despite high surgical success rate, mainly because of cone death. RD causes the infiltration of activated immune cells, but it is not clear whether and how infiltrating inflammatory cells contribute to cone cell loss. METHODS: Vitreous samples from patients with RD and from control patients with macular hole were analyzed to characterize the inflammatory response to RD. A mouse model of RD and retinal explants culture were then used to explore the mechanisms leading to cone death. RESULTS: Analysis of vitreous samples confirms that RD induces a marked inflammatory response with increased cytokine and chemokine expression in humans, which is closely mimicked by experimental murine RD. In this model, we corroborate that myeloid cells and T-lymphocytes contribute to cone loss, as the inhibition of their accumulation by Thrombospondin 1 (TSP1) increased cone survival. Using monocyte/retinal co-cultures and TSP1 treatment in RD, we demonstrate that immune cell infiltration downregulates rod-derived cone viability factor (RdCVF), which physiologically regulates glucose uptake in cones. Insulin and the insulin sensitizers rosiglitazone and metformin prevent in part the RD-induced cone loss in vivo, despite the persistence of inflammation CONCLUSION: Our results describe a new mechanism by which inflammation induces cone death in RD, likely through cone starvation due to the downregulation of RdCVF that could be reversed by insulin. Therapeutic inhibition of inflammation and stimulation of glucose availability in cones by insulin signaling might prevent RD-associated cone death until the RD can be surgically repaired and improve visual outcome after RD. TRIAL REGISTRATION: ClinicalTrials.gov NCT03318588.

Chemokine CXCL-1: activity in the vitreous during proliferative vitreoretinopathy.

The aim of this study was to investigate CXCL-1 chemokine levels in the vitreous during rhegmatogenous retinal detachment (RRD) with and without proliferative vitreoretinopathy (PVR) and identify possible correlations with clinical parameters (extent and duration or RRD and PVR grade). Vitreous samples from patients with primary RRD with or without PVR were collected and assayed using a double antibody enzyme-linked immunosorbent assay (ELISA). Eleven vitreous samples from organ donors were employed as a control group. CXCL-1 levels were measured in 35 vitreous samples from 35 RRD patients. Mean CXCL-1 levels (64·82 ± 6·47 pg/ml) were significantly higher (P = 0·048) compared to controls. There was a significant positive correlation between CXCL-1 levels and the extent of the detachment (r = 0·794, P = 0·006). Peak CXCL-1 levels coincided with 3+ quadrant RRD, an interim of 29-60 days' duration and PVR grade B. Increased CXCL-1 levels may be indicative of mild inflammation in the detached retina and the adjacent vitreous. The results of the present study may provide novel insight into the complex interactions taking place during the early and late stages of RRD complicated by PVR.

[Behcet disease -- case report]. / Boala Behcet -- caz clinic.

Behçet's Disease is a chronic, systemic, relapsing disease, an occlusive vasculitis which is immune complex mediated. Ocular involvement is usually bilateral, often asymmetric, associated with the loss of visual functions. This case presentation is a way to reveal an uncommon debut and evolution of the pathology using diagnostic criteria for Behçet's Disease.

CONGENITAL TOXOPLASMOSIS ASSOCIATED WITH TRACTIONAL RETINAL DETACHMENT.

PURPOSE: We report a case of congenital toxoplasmosis associated with retinal detachment. METHODS: A 9-month-old white boy presented a unilateral tractional retina detachment associated with congenital toxoplasmosis retinochoroiditis. RESULTS: The diagnosis is supported by positive IgG (>400) for toxoplasmosis and intracranial calcification on magnetic resonance imaging, along with positive family history of Toxoplasma infection in the mother. CONCLUSION: Tractional retinal detachment is an infrequent and unconventional presentation of congenital Toxoplasma infection. Inflammatory interference with normal sequence of vitreous development may explain pathogenesis of tractional retinal detachments in the setting of congenital ocular toxoplasmosis.

[Immunomodulatory role of perfluorane in the preoperative preparation of patients with rhegmatogenous retinal detachment].

The paper presents the results of studying the effect of 10% perfluorane (PF) emulsion intravenously injected 1-2 days before surgical treatment for rhegmatogenous retinal detachment on the levels of the cytokines IL-1beta, TNF-alpha, IL-6, and IL-4 in the serum and subretinal fluid of patients. PF infusion was found to exert an immunomodulatory effect that favored a short-term increase in the serum level of proinflammatory cytokines (IL- 1beta and IL-6) at week 1 and TNF-alpha on day 1) with their gradual normalization. The subretinal fluid showed recovery of the mechanisms for local immunological reactions; eye inflammation reduced due to the decreased production of proinflammatory cytokines and simultaneously the elevated level of the anti-inflammatory cytokine IL-4.

Clinical and molecular markers in retinal detachment-From hyperreflective points to stem cells and inflammation.

PURPOSE: Retinal detachment (RD) is one of the most frequently diagnosed ophthalmologic conditions requiring prompt surgical intervention. Combination of proper surgical technique and new diagnostic markers, both clinical and molecular, can help improve the diagnosis and prognosis of RD treatment. METHODS: 12 patients with rhegmatogenous RD (rRD) were included into the study after obtaining patient consent and Regional Ethical Approval (average age: 58.1 ± 17.4 years). OCT was performed before and after 23G vitrectomy for RD. Pure subretinal fluid (SRF) was collected during surgery and analyzed by protein array profiling on a panel of 105 inflammatory cytokines (Human XL Cytokine Array), while the effect of SRF upon human macrophages-driven phagocytosis of apoptotic retinal pigment epithelial (RPE) cells ex vivo was quantified by flow cytometry. Immunohistochemistry (IHC) of retinectomized tissue due to PVR caused by RD was performed to determine presence of markers for microglial cells (CD34), macrophages and activated microglia (CD68), regulator of the immune response to infection (NFkB), progenitor and stem cell marker (Sox2), pluripotency marker (Oct4) and intermediate filament markers (GFAP and Nestin). RESULTS: OCT of fresh RD patients contained pre-operatively hyper reflective points (HRPs) at the detached neuroretina border and proximal to the RPE layer-their size and number decreased following successful reattachment surgery. IHC of the retinectomized tissue from detached retina due to severe PVR showed presence of cell conglomerates at the detached neuroretina border which were positive for CD68, NFkB, Sox2 and GFAP, less positive for CD47 and Nestin and negative for Oct4 and CD34. The SRF contained at least 37 cytokines with higher, and 4 cytokine with lower concentration compared to that in vitreous from non-RD pathology; when used as conditional medium to human macrophages ex vivo, the SRF doubled their capacity for engulfing dying RPEs. CONCLUSIONS: Fresh RD can be hallmarked by presence of HRPs at the detached neuroretina border on OCT; the HRPs decrease in size and number after successful reattachment surgery, and likely resemble the macrophage conglomerates seen by IHC. The neuroretina in RD contains progenitor/stem-like cells and signs of inflammatory reaction, while the SRF contains inflammatory cytokines and other factors which increase the ability of professional phagocytes to engulf dying RPE, or for that matter, other dying cells in the retina.

Levels of Anti-Retinal Antibodies in Retinal Detachment and Proliferative Vitreoretinopathy.

PURPOSE: The purpose of the study is to investigate the correlation between intraocular anti-retinal antibodies and clinical measurements in patients with rhegmatogenous retinal detachment (RRD) and proliferative vitreoretinopathy (PVR). MATERIAL AND METHODS: Aqueous humor and vitreous samples were collected from patients with RRD, PVR, and from control subjects with macular hole. The levels of total protein (TP), IgG, and anti-retinal antibodies were determined with a bicinchoninic acid assay, enzyme-linked immunosorbent assay, and dot blot, respectively. Correlations between these measurements were assessed using Pearson's correlation test. Analysis of variance followed by a post-hoc test or the Student t-test was used to compare differences between groups. RESULTS: The levels of anti-retinal antibodies and IgG were correlated with each other (P < 0.010). The IgG concentration was higher in patients with PVR than in controls in both the aqueous humor (P < 0.001) and the vitreous (P < 0.001), but not in patients with RRD. Conversely, TP levels and anti-retinal antibodies in both ocular fluids from RRD and PVR patients did not significantly differ from the controls. In a subgroup analysis, vitreal anti-retinal antibody levels were correlated with average macular thickness in the re-attached macula following surgery for macula-off RRD/PVR (P = 0.012). Furthermore, patients with post-operative cystoid macular edema had a higher level of vitreal anti-retinal antibodies than those without (P = 0.009). CONCLUSIONS: Intravitreal anti-retinal antibodies were increased in the eyes with maculopathy after surgical intervention for RRD/PVR.

IL-10 inhibits retinal pigment epithelium cell proliferation and migration through regulation of VEGF in rhegmatogenous retinal detachment.

Rhegmatogenous retinal detachment (RRD) is a disorder of the eye that affects physical and mental health. Retinal pigment epithelium (RPE) is closely associated with RRD, and it is hypothesized that RPE-secreted inflammatory cytokines may induce early pathological changes of RRD and may participate in RPE proliferation and migration. The present study determined a role for interleukin (IL)­10 as an RPE­secreted immune regulatory factor that contributes to RRD. A rat RRD model was established and RPE cells were isolated and cultivated. RPE cells were randomly divided into four groups, three treated with different concentrations of IL­10 (100, 50, and 20 mM) and one untreated. RPE cell proliferation was evaluated by MTT assay and the activity of caspase­3 was also measured. RPE cell invasion was determined by Transwell assay. Vascular endothelial growth factor A (VEGF) expression was examined by reverse transcription­quantitative polymerase chain reaction and western blotting; IL­1 and IL­6 levels were measured by ELISA. IL­10 treatment suppressed RPE cell proliferation and migration, promoted caspase­3 activity, inhibited VEGF mRNA and protein expression, and downregulated the secretion of inflammatory cytokines IL­1 and IL­6 in RRD group compared with the untreated Model group. The aforementioned effects of IL­10 became more evident with increasing IL­10 concentration. IL­10 suppressed inflammation, facilitated RPE cell apoptosis and inhibited cell proliferation and migration through the regulation of VEGF expression.

Elevated cytokine levels in vitreous as biomarkers of disease severity in infectious endophthalmitis.

PURPOSE: To investigate the immunopathogenesis of endophthalmitis, and determine if cytokine profiles could serve as biomarkers of disease severity in infectious endophthalmitis. MATERIALS AND METHODS: Vitreous samples of 46 patients clinically diagnosed as endophthalmitis (of which 25 were culture positive) and 20 non-infectious controls from patients with Retinal Detachment (RD) or diabetic retinopathy were included in the study. The cytokine and chemokine expression patterns of 40 immune mediators including 6 antiinflammatory cytokines, 15 proinflammatory cytokines, 9 Growth factors and 10 proinflammatory chemokines in the vitreous were were analyzed by multiplex cytokine immunoassay. In addition, significant immune mediators were correlated with initial and final visual acuity (VA). RESULTS: Our results demonstrated elevated expression of 16 mediators such as GCSF, GRO, IFN-γ, IL-1α, IL-1ß, IL-1 RA, IL-6, IL-8, IP-10, MCP-1, MCP-3, MIP-1α, IL-1ß, TGF-α, TNF-α in patients with culture positive endophthalmitis. Cytokine profile expression significantly differed between patients with proven endophthalmitis and the non-infectious controls in heat map analysis. PCoA plot indicated five mediators (IL-1RA, IL-6, IL-8, GRO, G-CSF) as biomarkers that could be Independent Predictors of Disease especially in culture negative cases. Correlation of cytokines with VA revealed strong association between the initial VA and intraocular levels of TGF-α, IL-1ß and IL-8 but there was no correlation with the severity or visual outcome of infection. CONCLUSION: In comparison to non-infectious ocular conditions, the pathogenesis of infectious endophthalmitis correlates with increased expression levels of IL-1RA, IL-6, IL-8, GRO, G-CSF. Understanding cytokine profiles in culture negative endophthalmitis patients could aid in therapy in non-responders to empirical antibiotic therapy.

Retinal S-antigen in human subretinal fluid.

Studies in experimental models of retinal detachment have proposed that the degree of visual recovery following retinal reattachment depends upon the extent of photoreceptor degeneration. A means of assessing this degeneration would help in establishing postoperative prognosis. S-antigen (S-Ag) is a unique retinal protein found in outer segment disc membranes and photoreceptor cells. In 36 cases of human rhegmatogenous retinal detachment, subretinal fluid (SRF) concentrations of S-Ag, measured by radioimmunoassay, ranged from 43 to 170 ng/ml (serum: 1-28 ng/ml). Analysis of variance showed a positive correlation with the duration of detachment (P less than 0.001). There was a two-fold increase in S-Ag concentrations during the first 2 weeks of detachment (P less than 0.005), with constant levels thereafter. These findings reflect progressive photoreceptor degeneration and/or ongoing synthesis of outer segment proteins in the detached retina that stop after the second week of detachment. SRF S-Ag levels may provide a prognostic indicator of visual recovery after reattachment as well as a sensitive measure of retinal metabolic activity during detachment.

Immunoreactive opsin content in subretinal fluid from patients with rhegmatogenous retinal detachments.

We determined the immunoreactive opsin content in the subretinal fluid from 16 patients with rhegmatogenous retinal detachment by enzyme-linked immunosorbent assay. The opsin content decreased, with the duration of the detachment, but there was no correlation between opsin content and the age of the patient or the extent of the retinal detachment.

Histopathological and immunohistochemical findings associated with a null mutation in the Norrie disease gene.

PURPOSE: To determine the clinical, histopathological, and immunohistochemical ocular changes associated with a null mutation in the Norrie disease protein (NDP) gene. METHODS: Tissue from a six-month-old boy with bilateral retrolental membranes and retinal detachment was obtained during vitreoretinal surgery. Histological sections were stained immunohistochemically with specific antibodies. No eye diseases with severe visual impairment or blindness were reported in the parents and their families. The NDP gene was analyzed by standard molecular genetic methods. RESULTS: A severe reduction in the number of retinal ganglion cells and a largely disarranged and hypoplastic inner nuclear layer were visible in the tissue specimen. Areas of the tissue with advanced pathology displayed massive fibrovascular proliferation in the vitreous cavity. Shrinkage and traction resulted in folding and detachment of the outer retina. Immunohistochemical reactivity for MIB(1) antigen demonstrated many proliferating cells in the vitreous, but no proliferative activity in the neuroretina. Retinal neurons showed a high grade of differentiation and expressed uniformly neuron-specific enolase and synaptophysin. A 1-base pair insertion (544/545insA) in the NDP gene was found in the affected boy. This mutation predicts a 'functional null-allele' due to a shift in the reading frame and, thus, a premature termination of mRNA translation after 55 instead of 133 amino acids. CONCLUSIONS: Loss of function of the NDP gene causes marked hypoplasia of the inner retinal cell layers and fibrovascular proliferation in the vitreous cavity, leading to retinal folding and detachment. The NDP therefore seems to play a critical role in terminal differentiation of the inner retinal cell layers and establishment and maintaining of anti-proliferative cellular interactions in the vitreous.

Immunoglobulins in paired specimens of vitreous and subretinal fluids from patients with rhegmatogenous retinal detachment.

Evidence suggests that there is a net movement of fluid through the retinal break in eyes with rhegmatogenous retinal detachment, this net movement being directed from the vitreous humour into the subretinal space. However, it remains uncertain how much fluid exchange occurs in both directions across such breaks. The concentration ratios of IgG/IgM or IgA/IgM, derived from assay of immunoglobulins in vitreous humour, subretinal fluid, and serum from a group of 19 such patients, suggest a lack of free, two-directional, fluid movement across the retinal break. Furthermore the IgG/IgM ratios for the two intraocular fluids were significantly greater than that of serum, this suggesting that these intraocular fluids are formed, at least in part, by a selective transduction of serum.

Further characterization of epiretinal membranes in human massive periretinal proliferation.

Periretinal membranes obtained at vitrectomy from three patients with massive periretinal proliferation were examined by immunofluorescence and electron microscopy. Immunofluorescent staining on fresh frozen sections showed positive stain with glial fibrillary acidic protein and a weaker stain with antibodies to actin, PBM-1 and laminin. Staining was negative for antibodies to actin, PBM-1 and laminin. Staining was negative for antibodies of collagen types I, III and IV. Electron microscopy revealed abundant glial cells arranged in a tubulo-acinar configuration with junctional complexes, apical microvillous processes and 9-10 nm cytoplasmic filaments.

[Proliferative vitreoretinopathy. Activation of the complement system]. / Die proliferative Vitreoretinopathie. Aktivierung des Komplementsystems.

The complement system is a principal constituent of humoral immune reactions. Because of the multitude of biological effects related to complement activation, we analyzed its potential pathophysiological importance in the development of proliferative vitreoretinopathy (PVR). Vitreous aspirates from patients with idiopathic PVR (n = 7) and traumatic PVR (n = 11) were examined for total vitreal protein, complement components C3, C3d, and C1q-fixed immunoglobulins using enzyme-linked immunosorbent assay (ELISA), SDS-Page and Western blotting. Total vitreal protein and C3 components were significantly elevated both in traumatic and idiopathic PVR. Elevated levels of C3d titers in both PVR forms reflect an activation of the complement system. C1q-fixed IgG suggests complement activation via the classic pathway as a result of a humoral antibody-dependent immune reaction.

[Immunomorphological study of the vitreous body and subretinal fluid in vitreoretinal proliferation]. / Etude immunomorphologique du vitré et du liquide sous-rétinien au cours de la prolifération vitréo-rétinienne.

Proliferative vitreoretinopathy (PVR) is a major complication of rhegmatogenous retinal detachment. Its pathogenesis remains poorly understood and the accurate nature of the growing cells on both surfaces of the detached retina has not been yet determined. We undertook an immunocytological study on 28 specimens of vitreous or subretinal fluid removed from patients with PVR. Five main types of cells could be identified: heavily pigmented cells, poorly pigmented ones, large totally unpigmented macrophage-like ones, smaller unpigmented cells and lymphocytes. Analysis of intravitreal pigment granules showed two different types of pigmented cells, those with lipofuscin and melanin and those with melanin without any granules of lipofuscin, which could originate from ciliary or iris pigment epithelia. Immunostaining procedures confirmed the epithelial non macrophagic lineage of the intravitreal and subretinal cells. Lymphocytes were only B cells. These results confirm the importance of proliferative process during the course of PVR and shows the involvement of other ocular structures other than the retinal pigment epithelium.

[Autoimmunity against the retina in idiopathic retinal detachment. Study of 50 cases]. / Recherche de l'auto-immunité contre la rétine dans les décollements rétiniens idiopathiques. Etude de 50 cas.

Auto-immunity against the retina was studied on fifty patients suffering from retinal detachment. The results of the present study confirm the development of auto-immunity against the retina in long standing retinal detachments, which has already been demonstrated by other authors. In addition, the present study shows a significant correlation between the development of auto-immunity against the retina and the surgical treatment on one hand, and evidence of epiretinal proliferation and retraction on the other hand. It is suggested that auto-immunity against the retina may be the result of endocular inflammation which may be one of the causes of epiretinal proliferation and retraction.