TNFRSF10A downregulation induces retinal pigment epithelium degeneration during the pathogenesis of age-related macular degeneration and central serous chorioretinopathy.

Age-related macular degeneration (AMD) and central serous chorioretinopathy (CSC) are common diseases that can cause vision loss in older and younger populations. These diseases share pathophysiological conditions derived from retinal pigment epithelium (RPE) dysfunction. Tumor necrosis factor receptor superfamily 10A (TNFRSF10A)-LOC389641 with the same lead single-nucleotide polymorphism (SNP) (rs13278062) is the only overlapped susceptibility locus found in both AMD and CSC through genome-wide association studies. This lead SNP has been reported to alter the transcriptional activity of TNFRSF10A. This study aimed to elucidate the function of TNFRSF10A in RPE degeneration using human primary RPE cells and Tnfrsf10 knockout (Tnfrsf10-/-) mice. TNFRSF10A was found to be localized in human RPE. In vitro assays revealed that a T allele of rs13278062, the risk allele for AMD and CSC, downregulated TNFRSF10A transcription in RPE, leading to decreased cell viability and increased apoptosis through protein kinase C-α (PKCA) downregulation. Treatment with phorbol 12-myristate 13-acetate, a PKC activator, rescued the cell viability. Morphological RPE abnormality was found in the retina of Tnfrsf10-/- mice. Our data suggest that downregulation of TNFRSF10A expression inactivates PKCA signaling and causes cellular vulnerability of the RPE, which may contribute to the pathogenesis of AMD and CSC.

The factors associated with retinal pigment epithelium tear development in the early phase after treatment initiation for age-related macular degeneration.

PURPOSE: This study aimed to evaluate the factors associated with retinal pigment epithelium (RPE) tear development in the early phase after anti-vascular endothelial growth factor (VEGF) drug initiation in eyes with neovascular age-related macular degeneration (nAMD) and retinal pigment epithelial detachment (PED). METHODS: Treatment-naive eyes with nAMD and PED for which anti-VEGF drug injections had been initiated and followed up for at least 3 months after the 1st anti-VEGF drug injection, were retrospectively investigated. Baseline characteristics of the PEDs, including type, height, and area, were evaluated using fundus photographs, fluorescein angiography, and optical coherence tomography images. The association between patient age, sex, medical history, PED characteristics, and the development of RPE tears within 3 months of starting anti-VEGF therapy was examined. RESULTS: This study included 244 eyes (230 patients; mean age 75.0 years, 159 males and 71 females). RPE tears occurred in 13 eyes (5.3%) within 3 months of the start of anti-VEGF therapy. Multivariate analysis showed an association of the development of RPE tears with PED height (every 100 µm, odds ratio [OR]: 1.50, 95% confidence interval [CI]: 1.07-2.12, p = 0.019), PED area (every 10 mm2, OR: 3.02, CI: 1.22-7.46, p = 0.016), and the presence of fibrovascular PED (OR: 59.22, CI: 4.12-850.59, p = 0.002). Eyes with cleft (the hypo-reflective space beneath the fibrovascular PED) were more likely to develop an RPE tear (p = 0.01, χ-square test). CONCLUSIONS: Fibrovascular PED, large PED area, high PED height, and the cleft finding are independent risk factors for the development of RPE tears early after the administration of anti-VEGF drugs.

Increased vitreous levels of B cell activation factor (BAFF) and soluble interleukin-6 receptor in patients with macular edema due to uveitis related to Behçet's disease and sarcoidosis.

PURPOSE: Uveitis accounts for 10-15% of all cases of blindness in the developed world. Uveitic macular edema (UME) is a primary cause of permanent visual impairment in patients with uveitis. Because proinflammatory mediators elicit inflammation and lead to UME, we determined the profiles of proinflammatory mediators associated with complications, such as ME, in the vitreous humor of patients with panuveitis related to Behçet's disease (BD) and sarcoidosis. METHODS: In this retrospective study, we enrolled 21 patients with uveitis, including 6 with BD and 15 with sarcoidosis, and 15 patients with idiopathic epiretinal membrane (iERM) at the Department of Ophthalmology, Kyushu University Hospital, between January 2008 and April 2016. Vitreous concentrations of 32 proinflammatory mediators, including cytokines and soluble receptors of tumor necrosis factor (TNF) and interleukin (IL)-6 families, were assessed using a bead-based multiplex assay and their association with clinical data was examined. RESULTS: The levels of proinflammatory mediators, including a proliferation-inducing ligand (APRIL), B cell activating factor belonging to the TNF family (BAFF), soluble cluster of differentiation 30 (sCD30), soluble TNF receptor-1 (sTNFR1), sTNFR2, TNF-α, IL-6, and soluble IL-6 receptor-α (sIL-6Rα), were significantly higher in patients with uveitis. With regard to clinical parameters in patients with uveitis, vitreous levels of BAFF and sIL-6Rα were prominently elevated in patients with UME compared to in those without UME (P < 0.01, respectively). CONCLUSIONS: Our results suggest that elevated vitreous levels of BAFF and sIL-6Rα are associated with the pathogenesis of UME in patients with panuveitis related to BD and sarcoidosis.

One-year efficacy of "rescue photodynamic therapy" for patients with typical age-related macular degeneration, polypoidal choroidal vasculopathy, and pachychoroid neovasculopathy refractory to anti-vascular endothelial growth factor therapy.

PURPOSE: This study aimed to evaluate the one-year outcomes of photodynamic therapy (PDT) as a rescue treatment for age-related macular degeneration (AMD) refractory to anti-vascular endothelial growth factor (VEGF) therapy. METHODS: Patients with AMD refractory to anti-VEGF therapy, treated with "rescue-PDT" were retrospectively investigated. The time of PDT was defined as the baseline value. Baseline characteristics including sex, age, best-corrected visual acuity (BCVA), central macular thickness (CMT), and foveal choroidal thickness (FCT) were examined. The changes in BCVA, CMT, and recurrence were also assessed at the 1-year follow-up. The logMAR VA change of 0.3 or more was defined as "improved" or "declined." RESULTS: Twenty-three consecutive eyes (typical AMD: 10 eyes, polypoidal choroidal vasculopathy: 10 eyes, and pachychoroid neovasculopathy: 3 eyes), which underwent "rescue-PDT," were analyzed in this study. The BCVA was improved in three patients and maintained in 20 patients at 12 months after PDT (mean BCVA change: 0.11 ± 0.19). The CMT improved in 19 patients (82.6%), and the mean CMT changed from 318.5 ± 93.7 µm to 225.9 ± 51.6 µm (p < 0.01) 12 months after PDT. "Retreatment" of anti-VEGF drug injections was considered if the retinal fluid or retinal hemorrhage recurred after PDT. The baseline FCT of the "retreatment group (15 eyes)" was significantly lower than that of the "no retreatment group (8 eyes)" (206.3 ± 50.7 µm vs 293.9 ± 85.7 µm: p = 0.033). CONCLUSIONS: PDT could be an effective treatment option for anti-VEGF refractory AMD to maintain visual acuity and control retinal fluid for up to 12 months.

Characteristics of retinal pigment epithelium elevations preceding exudative age-related macular degeneration in Japanese.

INTRODUCTION: Drusen and pigmentary abnormality are found as the hallmark to predict progression of age-related macular degeneration (AMD). In Asian populations, exudative AMD often appears in the absence of drusen but are rather accompanied by pigmentary abnormality. Recently, shallow irregular retinal-pigment-epithelium (RPE) elevations (SIRE) has been shown as a sign of subclinical non-exudative macular neovascularization. In this study, we aimed to investigate the characteristics of optical coherence tomography (OCT) findings including SIRE before the appearance of exudative AMD. METHODS: We retrospective reviewed 32 cases of exudative AMD that occurred in the fellow eye within the 5-years-observation period. Color fundus photography, OCT, and fluorescein/indocyanine green angiography at the beginning of observation and at the time when exudative AMD appeared were examined to diagnose SIRE and the subtype of exudative AMD. RESULTS: Exudative AMD were found in 19 eyes with large drusen and 13 eyes without large drusen. Mean sub-foveal choroidal thickness without large drusen were significantly thicker than those with large drusen (336 ± 109 and 220 ± 96 µm, respectively; mean± SD). Six eyes with pachychoroid neovasculopathy, 4 eyes with Type 1 macular neovascularization, and 3 eyes with PCV had occurred in the fellow eye without large drusen. Among those, 6 eyes had been accompanied by SIRE with a greatest transverse linear dimension of 1 mm or more at the beginning of observation-period. Besides, small RPE elevations with a longest diameter of less than 1 mm had been observed in other 5 eyes. Three cases of polypoidal choroidal vasculopathy had originated from small RPE elevations. Moreover, pachyvessels, choriocapillaris thinning, or choroidal hyperpermeability were observed with SIRE or small RPE elevation. CONCLUSIONS: There is a non-drusen type of exudative AMD that originates from small RPE elevations as well as SIRE.

RIP1 kinase mediates angiogenesis by modulating macrophages in experimental neovascularization.

Inflammation plays an important role in pathological angiogenesis. Receptor-interacting protein 1 (RIP1) is highly expressed in inflammatory cells and is known to play an important role in the regulation of apoptosis, necroptosis, and inflammation; however, a comprehensive description of its role in angiogenesis remains elusive. Here, we show that RIP1 is abundantly expressed in infiltrating macrophages during angiogenesis, and genetic or pharmacological inhibition of RIP1 kinase activity using kinase-inactive RIP1K45A/K45A mice or necrostatin-1 attenuates angiogenesis in laser-induced choroidal neovascularization, Matrigel plug angiogenesis, and alkali injury-induced corneal neovascularization in mice. The inhibitory effect on angiogenesis is mediated by caspase activation through a kinase-independent function of RIP1 and RIP3. Mechanistically, infiltrating macrophages are the key target of RIP1 kinase inhibition to attenuate pathological angiogenesis. Inhibition of RIP1 kinase activity is associated with caspase activation in infiltrating macrophages and decreased expression of proangiogenic M2-like markers but not M1-like markers. Similarly, in vitro, catalytic inhibition of RIP1 down-regulates the expression of M2-like markers in interleukin-4-activated bone marrow-derived macrophages, and this effect is blocked by simultaneous caspase inhibition. Collectively, these results demonstrate a nonnecrotic function of RIP1 kinase activity and suggest that RIP1-mediated modulation of macrophage activation may be a therapeutic target of pathological angiogenesis.

Genetic LAMP2 deficiency accelerates the age-associated formation of basal laminar deposits in the retina.

The early stages of age-related macular degeneration (AMD) are characterized by the accumulation of basal laminar deposits (BLamDs). The mechanism for BLamDs accumulating between the retinal pigment epithelium (RPE) and its basal lamina remains elusive. Here we examined the role in AMD of lysosome-associated membrane protein-2 (LAMP2), a glycoprotein that plays a critical role in lysosomal biogenesis and maturation of autophagosomes/phagosomes. LAMP2 was preferentially expressed by RPE cells, and its expression declined with age. Deletion of the Lamp2 gene in mice resulted in age-dependent autofluorescence abnormalities of the fundus, thickening of Bruch's membrane, and the formation of BLamDs, resembling histopathological changes occurring in AMD. Moreover, LAMP2-deficient mice developed molecular signatures similar to those found in human AMD-namely, the accumulation of APOE, APOA1, clusterin, and vitronectin-adjacent to BLamDs. In contrast, collagen 4, laminin, and fibronectin, which are extracellular matrix proteins constituting RPE basal lamina and Bruch's membrane were reduced in Lamp2 knockout (KO) mice. Mechanistically, retarded phagocytic degradation of photoreceptor outer segments compromised lysosomal degradation and increased exocytosis in LAMP2-deficient RPE cells. The accumulation of BLamDs observed in LAMP2-deficient mice was eventually followed by loss of the RPE and photoreceptors. Finally, we observed loss of LAMP2 expression along with ultramicroscopic features of abnormal phagocytosis and exocytosis in eyes from AMD patients but not from control individuals. Taken together, these results indicate an important role for LAMP2 in RPE function in health and disease, suggesting that LAMP2 reduction may contribute to the formation of BLamDs in AMD.

Lysosome-associated membrane protein-2 deficiency increases the risk of reactive oxygen species-induced ferroptosis in retinal pigment epithelial cells.

Lysosome-associated membrane protein-2 (LAMP2), is a highly glycosylated lysosomal membrane protein involved in chaperone mediated autophagy. Mutations of LAMP2 cause the classic triad of myopathy, cardiomyopathy and encephalopathy of Danon disease (DD). Additionally, retinopathy has also been observed in young DD patients, leading to vision loss. Emerging evidence show LAMP2-deficiency to be involved in oxidative stress (ROS) but the mechanism remains obscure. In the present study, we found that tert-butyl hydroperoxide or antimycin A induced more cell death in LAMP2 knockdown (LAMP2-KD) than in control ARPE-19 cells. Mechanistically, LAMP2-KD reduced the concentration of cytosolic cysteine, resulting in low glutathione (GSH), inferior antioxidant capability and mitochondrial lipid peroxidation. ROS induced RPE cell death through ferroptosis. Inhibition of glutathione peroxidase 4 (GPx4) increased lethality in LAMP2-KD cells compared to controls. Cysteine and glutamine supplementation restored GSH and prevented ROS-induced cell death of LAMP2-KD RPE cells.

INTERNAL LIMITING MEMBRANE PEELING-DEPENDENT RETINAL STRUCTURAL CHANGES AFTER VITRECTOMY IN RHEGMATOGENOUS RETINAL DETACHMENT.

PURPOSE: To examine retinal changes after vitrectomy with internal limiting membrane (ILM) peeling, we used 3-dimensional optical coherence tomography (3D-OCT) in rhegmatogenous retinal detachment cases. METHODS: The 68 eyes from 67 patients with rhegmatogenous retinal detachment were studied, including 35 detached macula cases (51%) and 33 attached macula cases. Internal limiting membrane peeling was performed with fine forceps after brilliant blue G staining. The 3D-OCT images were obtained with volume-rendering technologies from cross-sectional OCT images. RESULTS: The 3D-OCT detected 45 eyes (66%) with ILM peeling-dependent retinal changes, including dissociated optic nerve fiber layer appearance, dimple sign, temporal macular thinning, ILM peeling area thinning, or forceps-related retinal thinning. The ILM peeled area was detectable in only 9 eyes with 3D-OCT, whereas it was undetectable in other 59 eyes. The dissociated optic nerve fiber layer appearance was detected in 8 of the total cases (12%), and dimple signs were observed in 14 cases (21%). Forceps-related thinning was also noted in eight cases (24%) of attached macula cases and in four cases (11%) of detached macula cases. No postoperative macular pucker was noted in the observational period. CONCLUSION: The 3D-OCT clearly revealed spatial and time-dependent retinal changes after ILM peeling. The changes occurred in 2 months and remained thereafter.

INCOMPLETE REPAIR OF RETINAL STRUCTURE AFTER VITRECTOMY WITH INTERNAL LIMITING MEMBRANE PEELING.

PURPOSE: To examine retinal changes after vitrectomy with internal limiting membrane (ILM) peeling, we used a cynomolgus monkey model and focused on surgical damages of ILM peeling for long observational period of 3 years. METHODS: Vitrectomy was performed followed by ILM peeling similar to clinical settings in humans. Ultrastructural changes of the retina were investigated by light, transmission, and scanning electron microscopy at 3 months and 3 years after ILM peeling. RESULTS: Ultrastructural study showed that the ILM peeled area was still clearly recognized after 3 years. The Müller cell processes covered most of the retina; however, the nerve fiber layer was partly uncovered and exposed to the vitreous space. The arcuate linear nerve fiber bundles were observed as comparable with dissociated optic nerve fiber layer appearance. Small round retinal surface defects were also observed around macula, resembling the dimple sign. Forceps-related retinal thinning was also found on the edge of ILM peeling, where we started peeling with fine forceps. CONCLUSION: The ultrastructural studies showed that most of ILM peeling area was covered with glial cells during wound healing processes. Retinal changes were found comparable with dissociated optic nerve fiber layer appearance or dimple sign, which were clinically observed with optical coherence tomography.

Astrocyte-mediated ischemic tolerance.

Preconditioning (PC) using a preceding sublethal ischemic insult is an attractive strategy for protecting neurons by inducing ischemic tolerance in the brain. Although the underlying molecular mechanisms have been extensively studied, almost all studies have focused on neurons. Here, using a middle cerebral artery occlusion model in mice, we show that astrocytes play an essential role in the induction of brain ischemic tolerance. PC caused activation of glial cells without producing any noticeable brain damage. The spatiotemporal pattern of astrocytic, but not microglial, activation correlated well with that of ischemic tolerance. Interestingly, such activation in astrocytes lasted at least 8 weeks. Importantly, inhibiting astrocytes with fluorocitrate abolished the induction of ischemic tolerance. To investigate the underlying mechanisms, we focused on the P2X7 receptor as a key molecule in astrocyte-mediated ischemic tolerance. P2X7 receptors were dramatically upregulated in activated astrocytes. PC-induced ischemic tolerance was abolished in P2X7 receptor knock-out mice. Moreover, our results suggest that hypoxia-inducible factor-1α, a well known mediator of ischemic tolerance, is involved in P2X7 receptor-mediated ischemic tolerance. Unlike previous reports focusing on neuron-based mechanisms, our results show that astrocytes play indispensable roles in inducing ischemic tolerance, and that upregulation of P2X7 receptors in astrocytes is essential.

Factors affecting visual acuity after cataract surgery in patients with retinitis pigmentosa.

PURPOSE: To investigate the factors affecting visual acuity after cataract surgery in patients with retinitis pigmentosa (RP). DESIGN: Retrospective, observational study. PARTICIPANTS: We retrospectively reviewed the charts of a consecutive series of 40 patients with RP who underwent cataract surgery. METHODS: The changes in preoperative and postoperative best-corrected visual acuity (BCVA) were measured. We investigated the relation between preoperative mean deviation (MD) value on the Humphrey Field Analyzer (HFA: the central 10-2 program; Humphrey Instruments, Inc, San Leandro, CA) and final BCVA. We also investigated the relationship between preoperative ellipsoid zone (EZ; also called the inner/outer segment junction) conditions and final BCVA. In addition, we showed the prevalence of macular complications and capsule complications. MAIN OUTCOME MEASURES: The BCVA, slit-lamp biomicroscopic analysis, visual field, and optical coherence tomography (OCT) were obtained. RESULTS: The mean of the BCVA significantly improved after cataract surgery from 0.76 (range, -0.08 to 2.30) to 0.45 (range, -0.18 to 2.00) (P < 0.005). However, final BCVA did not improve in 30 eyes (53.6%). The preoperative MD value and the final BCVA were significantly correlated, and the final BCVA significantly improved in the less advanced RP group (MD was ≥-15 decibels [dB]). The final BCVA was significantly better in the group in which preoperative OCT showed a normal EZ than in the groups in which the EZ was abnormal or not visible. Posterior capsular opacification was observed in 47 eyes (83.9%), and 23 eyes (41.1%) underwent YAG laser capsulotomy within a mean follow-up time of 3 years. CONCLUSIONS: Final BCVA in approximately half of the eyes improved after cataract surgery in patients with RP. The preoperative ophthalmic examinations that may reflect macular (or foveal) function, such as HFA 10-2 program and OCT, are important parameters to assess postoperative visual outcome.

Brilliant Blue G double staining enhances successful internal limiting membrane peeling with minimal adverse effect by low cellular permeability into live cells.

PURPOSE: Brilliant Blue G is used as a surgical adjuvant for retinal surgery. Although BBG double or multiple staining was reported, the effectiveness and safety of repeated staining is still elusive. To further examine the effectiveness and safety, we examined BBG in clinical cases in vivo, primary cell culture in vitro, and surgically resected specimen ex vivo. METHODS: A retrospective interventional case series with in vitro and ex vivo studies were performed. Vitrectomy was performed in 28 cases of epiretinal membrane with BBG single to multiple staining. The surgically resected membranes were stained by BBG with or without cellular fixation. Primary cell cultures were examined with BBG and live/death cell markers, such as Calcein AM and TUNEL. RESULTS: Single staining provided satisfactory staining in seven cases. Double or multiple staining substantially visualized internal limiting membrane (21 cases), especially the edges of remaining internal limiting membrane (11 cases). Adverse retinal staining was not noted and the final visual acuity showed no difference with multiple staining. The live cells barely stained with BBG, while some dead cells were stained. CONCLUSION: Brilliant Blue G multiple staining substantially enhanced the visualization of internal limiting membrane. The absence of abnormal staining supports the safety of repeated BBG staining.

Wide-Field Choroidal Thickness Analysis after Half-Fluence Photodynamic Therapy Combined with Intravitreal Aflibercept Injection in Pachychoroid Neovasculopathy.

Background: Pachychoroid neovasculopathy (PNV) is a pachychoroid-spectrum disease. As blood circulation throughout the choroid may be involved in PNV pathogenesis, analysis using ultra-wide-field (UWF) fundus imaging is crucial. We evaluated choroidal thickness after half-fluence photodynamic therapy (PDT) combined with intravitreal aflibercept injection for PNV using UWF swept-source optical coherence tomography. Methods: Seventeen eyes with PNV that underwent half-fluence PDT with an adjuvant single intravitreal aflibercept injection were analyzed. To compare choroidal thicknesses in the central and peripheral choroids, we set subfields <3, <9, and 9-18 mm from the fovea. The <9 and 9-18 mm subfields were divided into four quadrants. Results: Choroidal thickness in each subfield decreased significantly after half-fluence PDT (p < 0.001); this reduction was more pronounced in the central area. We also investigated the relationship between the dominant side of the deep choroidal veins that harbor choroidal vein efflux from the macula. When choroidal thickness in the supratemporal and infratemporal 9 mm subfields were evaluated, the ratio of choroidal thickness reduction was not significantly different between the dominant and non-dominant sides. The dominant side was not associated with the extent of choroidal thickness reduction in PNV. Conclusions: Half-fluence PDT caused thinning of the entire choroid, especially in the central area, in PNV.

Factors at the initial visit associated with poor visual outcomes in patients with acute retinal necrosis.

BACKGROUND/OBJECTIVE: Acute retinal necrosis (ARN) is a vision-threatening disease caused by herpesvirus infection. This study aimed to investigate the visual prognostic factors that could be determined at the initial visit. SUBJECTS AND METHODS: This retrospective study included 34 patients with ARN. Logistic regression analysis was employed to evaluate the associations between poor final visual outcomes and various factors, including poor initial visual acuity, presence of retinal detachment at the initial visit, posterior extension of necrotizing retinitis, and circumferential extension of necrotizing retinitis. Posterior extension was evaluated with three zonings, from the periphery (zone 3), mid-periphery (zone 2), and macula (zone 1). Circumferential extension was evaluated according to the degree of necrotizing retinitis lesions using ultra-wide fundus imaging. RESULTS: The mean logarithm of the minimum angle of resolution was 0.63 ± 0.68 at the initial visit and 0.83 ± 0.65 at 12 months after the initial visit. Seven patients had a retinal detachment. The distribution of posterior extension at the initial visit was 5 in zone 1, 20 in zone 2, and 9 in zone 3. The average of necrotizing retinitis lesion angle was 249 ± 115°. The logistic regression analysis revealed that participants with wide angles of necrotizing retinitis were associated with final poor vision, with an odds ratio of 1.28 per 30° increase (95%CI: 1.00-1.65, p = 0.03). CONCLUSIONS: Assessment of the widespread circumferential extension of white necrotizing retinal lesions at the initial visit is a crucial risk factor for the visual prognosis in ARN.

MutT homolog-1 attenuates oxidative DNA damage and delays photoreceptor cell death in inherited retinal degeneration.

Retinitis pigmentosa (RP) is a genetically heterogenous group of inherited retinal degenerative diseases resulting from photoreceptor cell death and affecting >1 million persons globally. Although oxidative stress has been implicated in the pathogenesis of RP, the mechanisms by which oxidative stress mediates photoreceptor cell death are largely unknown. Here, we show that oxidation of nucleic acids is a key component in the initiation of death-signaling pathways in rd10 mice, a model of RP. Accumulation of 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxo-dG) increased in photoreceptor cells, and especially within their nuclei, in rd10 mice as well as in Royal College of Surgeons rats, another model of RP caused by different genetic mutations. Vitreous samples from humans with RP contained higher levels of 8-oxo-dG excreted than samples from nondegenerative controls. Transgenic overexpression of human MutT homolog-1, which hydrolyzes oxidized purine nucleoside triphosphates in the nucleotide pool, significantly attenuated 8-oxo-dG accumulation in nuclear DNA and photoreceptor cell death in rd10 mice, in addition to suppressing DNA single-strand break formation, poly(ADP-ribose) polymerase activation, and nuclear translocation of apoptosis-inducing factor. These findings indicate that oxidative DNA damage is an important process for the triggering of photoreceptor cell death in rd10 mice and suggest that stimulation of DNA repair enzymes may be a novel therapeutic approach to attenuate photoreceptor cell loss in RP.

The regulatory roles of apoptosis-inducing factor in the formation and regression processes of ocular neovascularization.

The role of apoptosis in the formation and regression of neovascularization is largely hypothesized, although the detailed mechanism remains unclear. Inflammatory cells and endothelial cells both participate and interact during neovascularization. During the early stage, these cells may migrate into an angiogenic site and form a pro-angiogenic microenvironment. Some angiogenic vessels appear to regress, whereas some vessels mature and remain. The control mechanisms of these processes, however, remain unknown. Previously, we reported that the prevention of mitochondrial apoptosis contributed to cellular survival via the prevention of the release of proapoptotic factors, such as apoptosis-inducing factor (AIF) and cytochrome c. In this study, we investigated the regulatory role of cellular apoptosis in angiogenesis using two models of ocular neovascularization: laser injury choroidal neovascularization and VEGF-induced corneal neovascularization in AIF-deficient mice. Averting apoptosis in AIF-deficient mice decreased apoptosis of leukocytes and endothelial cells compared to wild-type mice and resulted in the persistence of these cells at angiogenic sites in vitro and in vivo. Consequently, AIF deficiency expanded neovascularization and diminished vessel regression in these two models. We also observed that peritoneal macrophages from AIF-deficient mice showed anti-apoptotic survival compared to wild-type mice under conditions of starvation. Our data suggest that AIF-related apoptosis plays an important role in neovascularization and that mitochondria-regulated apoptosis could offer a new target for the treatment of pathological angiogenesis.

Clinical evidence of sustained chronic inflammatory reaction in retinitis pigmentosa.

PURPOSE: To study the nature of inflammatory reaction in eyes of patients with retinitis pigmentosa (RP) and its possible role in the pathogenesis of RP. DESIGN: Retrospective, observational study. PARTICIPANTS AND CONTROLS: Three hundred seventy-one consecutive patients diagnosed with typical RP were included in this study. We included 165 patients without active inflammatory diseases, including 20 patients diagnosed with cataract, and 36 patients diagnosed with idiopathic epiretinal membrane as controls. METHODS: Density of the inflammatory cells in the anterior vitreous cavity was measured and graded by slit-lamp biomicroscopy. A multiplex enzyme-linked immunosorbent assay (ELISA) was performed to evaluate the concentration of cytokines and chemokines in aqueous humor and vitreous fluid of patients with RP and controls. In addition, we investigated the relationship between visual function and anterior vitreous cells in these patients. MAIN OUTCOME MEASURES: Slit-lamp biomicroscopic analysis, best-corrected visual acuity, visual field analysis, and multiplex ELISA. RESULTS: In 190 of 509 eyes with RP (37.3%), "1+" (5-9 cells per field) or more cells were observed in the anterior vitreous cavity. Strong inflammatory reaction with "2+" cells (10-30 cells per field) was associated with younger age. In the elderly patients with RP, significantly decreased visual function was seen in a group with "1+" or more cells (P<0.05). Moreover, the levels of a variety of proinflammatory cytokines and chemokines, including monocyte chemotactic protein-1, were increased both in the aqueous humor and vitreous fluid of RP patients compared with the levels in control patients. CONCLUSIONS: Sustained chronic inflammatory reaction may underlie the pathogenesis of RP, suggesting interventions for ocular inflammatory reaction as a potential treatment for patients with RP. FINANCIAL DISCLOSURE(S): The authors have no proprietary or commercial interest in any of the materials discussed in this article.

Laboratory evidence of sustained chronic inflammatory reaction in retinitis pigmentosa.

PURPOSE: To study the nature of retinal inflammatory response in rd10 mice, an animal model of retinitis pigmentosa (RP), and to investigate the effect of an antioxidant on retinal inflammation and photoreceptor apoptosis. DESIGN: Experimental study. PARTICIPANTS AND CONTROLS: This study included 42 untreated rd10 mice, 30 N-acetylcysteine (NAC)-treated rd10 mice, and 20 C57BL/6 mice as controls. METHODS: Real-time polymerase chain reaction (PCR) was performed to evaluate the expression levels of inflammatory factors (proinflammatory cytokines and chemokines) in rd10 mouse retinas. Rd10 mice were treated with an antioxidant NAC, and its effect on retinal inflammation and photoreceptor apoptosis were examined by immunohistochemistry. MAIN OUTCOME MEASURES: Real-time PCR and immunohistochemistry. RESULTS: We demonstrated sequential events involving increased expression of proinflammatory cytokines and chemokines, activation of microglia, and photoreceptor apoptosis during retinal degeneration of rd10 mice. Furthermore, antioxidant treatment with NAC prevented the photoreceptor cell death along with suppression of inflammatory factors and microglial activation. CONCLUSIONS: Sustained chronic inflammatory reaction may contribute to the pathogenesis of retinal degeneration in rd10 mice, suggesting interventions for ocular inflammatory reaction using antioxidants as a potential treatment for patients with RP. FINANCIAL DISCLOSURE(S): The authors have no proprietary or commercial interest in any of the materials discussed in this article.