NLRP3 Upregulation in Retinal Pigment Epithelium in Age-Related Macular Degeneration.

Inflammation and oxidative stress are involved in age-related macular degeneration (AMD) and possibly associated with an activation of neuronal apoptosis inhibitor protein/class II transcription activator of the Major Histocompatibility Complex (MHC)/heterokaryon incompatibility/telomerase-associated protein 1, leucine-rich repeat or nucleotide-binding domain, leucine-rich repeat-containing family, and pyrin domain-containing 3 (NLRP3) inflammasome. In the present study, we used a translational approach to address this hypothesis. In patients with AMD, we observed increased mRNA levels of NLRP3, pro-interleukin-1 beta (IL-1ß) and pro-IL-18 in AMD lesions of the retinal pigment epithelium (RPE) and photoreceptor. In vitro, a similar increase was evoked by oxidative stress or lipopolysaccharide (LPS) stimulation in the adult retinal pigment epithelium (ARPE-19) cell line, and the increase was reduced in siRNA transfected cells to knockdown NLRP3. Ultrastructural studies of ARPE-19 cells showed a swelling of the cytoplasm, mitochondrial damage, and occurrence of autophagosome-like structures. NLRP3 positive dots were detected within autophagosome-like structures or in the extracellular space. Next, we used a mouse model of AMD, Ccl2/Cx3cr1 double knockout on rd8 background (DKO rd8) to ascertain the in vivo relevance. Ultrastructural studies of the RPE of these mice showed damaged mitochondria, autophagosome-like structures, and cytoplasmic vacuoles, which are reminiscent of the pathology seen in stressed ARPE-19 cells. The data suggest that the NLRP3 inflammasome may contribute in AMD pathogenesis.

Wnt signaling in age-related macular degeneration: human macular tissue and mouse model.

BACKGROUND: The wingless-type MMTV integration site (Wnt) signaling is a group of signal transduction pathways. In canonical Wnt pathway, Wnt ligands bind to low-density lipoprotein receptor-related protein 5 or 6 (LRP5 or LRP6), resulting in phosphorylation and activation of the receptor. We hypothesize that canonical Wnt pathway plays a role in the retinal lesion of age-related macular degeneration (AMD), a leading cause of irreversible central visual loss in elderly. METHODS: We examined LRP6 phosphorylation and Wnt signaling cascade in human retinal sections and plasma kallistatin, an endogenous inhibitor of the Wnt pathway in AMD patients and non-AMD subjects. We also used the Ccl2 (-/-) /Cx3cr1 (-/-) /rd8 and Ccl2 (-/-) /Cx3cr1 (gfp/gfp) mouse models with AMD-like retinal degeneration to further explore the involvement of Wnt signaling activation in the retinal lesions in those models and to preclinically evaluate the role of Wnt signaling suppression as a potential therapeutic option for AMD. RESULTS: We found higher levels of LRP6 (a key Wnt signaling receptor) protein phosphorylation and transcripts of the Wnt pathway-targeted genes, as well as higher beta-catenin protein in AMD macula compared to controls. Kallistatin was decreased in the plasma of AMD patients. Retinal non-phosphorylated-ß-catenin and phosphorylated-LRP6 were higher in Ccl2 (-/-) /Cx3cr1 (-/-) /rd8 mice than that in wild type. Intravitreal administration of an anti-LRP6 antibody slowed the progression of retinal lesions in Ccl2 (-/-) /Cx3cr1 (-/-) /rd8 and Ccl2 (-/-) /Cx3cr1 (gfp/gfp) mice. Electroretinography of treated eyes exhibited larger amplitudes compared to controls in both mouse models. A2E, a retinoid byproduct associated with AMD was lower in the treated eyes of Ccl2 (-/-) /Cx3cr1 (-/-) /rd8 mice. Anti-LRP6 also suppressed the expression of Tnf-α and Icam-1 in Ccl2 (-/-) /Cx3cr1 (-/-) /rd8 retinas. CONCLUSIONS: Wnt signaling may be disturbed in AMD patients, which could contribute to the retinal inflammation and increased A2E levels found in AMD. Aberrant activation of canonical Wnt signaling might also contribute to the focal retinal degenerative lesions of mouse models with Ccl2 and Cx3cr1 deficiency, and intravitreal administration of anti-LRP6 antibody could be beneficial by deactivating the canonical Wnt pathway.

Platelet-derived growth factor (PDGF)-C inhibits neuroretinal apoptosis in a murine model of focal retinal degeneration.

Platelet-derived growth factor (PDGF)-C is a member of the PDGF family and is critical for neuronal survival in the central nervous system. We studied the possible survival and antiapoptotic effects of PDGF-C on focal retinal lesions in Ccl2(-/-)/Cx3cr1(-/-) on C57BL/6N [Crb1(rd8)] (DKO rd8) background mice, a model for progressive and focal retinal degeneration. We found no difference in transcript and protein expression of PDGF-C in the retina between DKO rd8 mice and wild type (WT, C57BL/6N). Recombinant PDGF-CC protein (500 ng/eye) was injected intravitreally into the right eye of DKO rd8 mice with phosphate-buffered saline as controls into the left eye. The retinal effects of PDGF-C were assessed by fundoscopy, ocular histopathology, A2E levels, apoptotic molecule analysis, and direct flat mount retinal vascular labeling. We found that the PDGF-CC-treated eyes showed slower progression or attenuation of the focal retinal lesions, lesser photoreceptor and retinal pigment epithelial degeneration resulting in better-preserved photoreceptor structure. Lower expression of apoptotic molecules was detected in the PDGF-CC-treated eyes than in controls. In addition, no retinal neovascularization was observed after PDGF-CC treatment. Our results demonstrate that PDGF-C potently ameliorates photoreceptor degeneration via the suppression of apoptotic pathways without inducing retinal angiogenesis. The protective effects of PDGF-C suggest a novel alternative approach for potential age-related retinal degeneration treatment.

Overexpression of IL-17RC associated with ocular sarcoidosis.

BACKGROUND: Sarcoidosis is a chronic inflammatory disease with a systemic granulomatous disorder affecting multiple organs including the eye. Both CD4+ T cell and macrophage have been linked to the pathogenesis of the disease. METHODS: The expression of IL-17RC was measured using FACS,immunohistochemistry and real-time PCR. Serum level of IL-17 was detected using ELISA. RESULTS: An elevated expression of IL-17RC on CD8+ T cells in peripheral blood was found in patients with ocular sarcoidosis as compared to healthy controls. Interestingly, we found a significant increase in the serum level of IL-17 in patients with ocular sarcoidosis as compared to healthy controls, which may be responsible for the induction of IL-17RC on CD8+ cells. In addition, IL-17RC appeared only in the retinal tissue of the patient with clinically active sarcoidosis. CONCLUSIONS: Our results suggested a potential involvement of IL-17RC+CD8+ T cells in pathogenesis of ocular sarcoidosis.

L-2-oxothiazolidine-4-carboxylic acid attenuates oxidative stress and inflammation in retinal pigment epithelium.

PURPOSE: Oxidant- and inflammation-induced damage to retinal pigment epithelial (RPE) cells is central to the pathogenesis of age-related macular degeneration (AMD). Thus, developing novel strategies to protect these cells is important. We reported previously on the robust antioxidant and therefore cell-protective effects of the cysteine pro-drug L-2-oxothiazolidine-4-carboxylic acid (OTC) in cultured human RPE cells. New reports citing a novel anti-inflammatory role for OTC in addition to the known glutathione-stimulating and antioxidant properties emerged recently; however, this role has not been evaluated in RPE cells or in intact retina. Given the crucial causative roles of oxidative stress and inflammation in AMD pathogenesis, knowing whether OTC might exhibit a similar benefit in this cell and tissue type has high clinical relevance; thus, we evaluated OTC in the present study. METHODS: ARPE-19 and primary RPE cells isolated from wild-type, Gpr109a(-/-) , or Slc5a8(-/-) mouse eyes were exposed to TNF-α in the presence or absence of OTC, followed by analysis of IL-6 and Ccl2 expression with real-time quantitative polymerase chain reaction or enzyme-linked immunosorbent assay. Cellular and molecular markers of inflammation and oxidative stress (i.e., IL-1ß, TGF-ß, ABCG1, ABCA1, reduced glutathione, and dihydroethidium) were evaluated in Ccl2(-/-)/Cx3cr1(-/-) double knockout mice on rd8 background (DKO rd8) treated with OTC (10 mg/ml) in drinking water for a period of 5 months. RESULTS: OTC treatment significantly inhibited the expression and secretion of IL-6 and Ccl2 in TNF-α-stimulated ARPE-19 cells. Studies conducted using DKO rd8 animals treated with OTC in drinking water confirmed these findings. Cellular and molecular markers of inflammation were significantly suppressed in the retinas of the OTC-treated DKO rd8 animals. Subsequent in vitro and in vivo studies of the possible mechanism(s) to explain these actions revealed that although OTC is an agonist of the anti-inflammatory G-protein coupled receptor GPR109A and a transportable substrate of the sodium-coupled monocarboxylate transporter SMCT1 (SLC5A8), these properties may play a role but do not explain entirely the anti-inflammatory effects this compound elicits in cultured RPE cells and the intact mouse retina. CONCLUSIONS: This study represents, to our knowledge, the first report of the suppressive effects of OTC on inflammation in cultured RPE cells and on inflammation and oxidative stress in the retina in vivo.

Upregulation of hypoxia-inducible factors and autophagy in von Hippel-Lindau-associated retinal hemangioblastoma.

PURPOSE: To describe pathological and molecular changes of three patients with clinically severe von Hippel-Lindau (VHL)-associated retinal hemangioblastoma (RH) with rapid progression. METHODS: Medical records, ocular histopathology, and transmission electron microscopy from three cases of VHL-associated RHs at the National Eye Institute were retrospectively reviewed. One eye of each patient was enucleated. Hypoxia-inducible factor (HIF) 1α and HIF2α expressions were identified by quantitative reverse transcription polymerase chain reaction (qRT-PCR) and immunohistochemistry. RESULTS: All three cases had rapidly growing RHs that were resistant to multiple conventional therapies and two (patients 1 and 2) were also resistant to multiple intravitreal anti-vascular endothelial growth factor (VEGF) treatments. Macroscopically, all the enucleated eyes had multiple RHs, serous retinal detachment, severe retinal disorganization and focal hemorrhages. Histopathology showed typical RHs composed of vacuolated foamy VHL cells and capillary networks. Retinal gliosis and hemorrhages were also presented. Additionally, T lymphocytes and macrophages infiltrated in the tumors of two patients resistant to anti-VEGF therapy. Immunohistochemistry, and qRT-PCR found upregulation of HIF1α in the retinal lesions of all eyes. Importantly, upregulation of HIF2α was exclusively detected in the two cases with inflammatory infiltration and resistance to anti-VEGF therapy. Ultrastructural images showed autophagy, lipid droplets, glycogen aggregations, and cytoplasmic degeneration in many VHL cells. CONCLUSIONS: Based on the histopathological and molecular pathological findings, autophagy, inflammation, and/or upregulation of HIF2α could potentially contribute to the aggressive course of RHs, resulting in the resistance to multiple anti-VEGF and radiation therapies in these patients.

Implications of DNA leakage in eyes of mutant mice.

Extranuclear DNA (enDNA) is not well studied ultrastructurally in the retinal pigment epithelium (RPE). We analyzed the retina and vastus medialis muscle of four mouse strains that are related to focal retinal degeneration by transmission electron microscopy (TEM) and EM immunolabeling. Evaluation of enDNA would imply the involvements of enDNA is either limited to the affected tissue or generalized in the whole body. Ultrastructural analysis and EM immunolabeling revealed that enDNA was present in the RPE cells but not in the muscle. These data suggest that enDNA could be unique to unhealthy RPE and a potential biomarker for cellular abnormality.

Molecular identification of bacterial DNA in the chorioretinal scars of chronic granulomatous disease.

PURPOSE: Chronic granulomatous disease (CGD) is an inherited disorder characterized by defects in phagocyte-derived nicotinamide adenine dinucleotide phosphate oxidase. It is typically diagnosed in childhood and leads to severe, recurrent bacterial or fungal infections. Chorioretinal lesions are the most common ocular manifestation. We sought to determine whether there are infectious agents in CGD-associated chorioretinopathy. METHODS: Medical records and ocular histopathology from CGD cases from January 1983 to January 2012 at the National Institutes of Health were retrospectively reviewed. Chorioretinal cells from normal and lesional tissues of the same eye were microdissected. Primers for Staphylococcus epidermidis, Staphylococcus aureus, Pseudomonas aeruginosa, Burkholderia sp., and a panbacterial 16S ribosomal DNA were used for polymerase chain reaction. RESULTS: Seventeen CGD patients had ocular tissues (16 autopsied cases and 1 chorioretinal biopsy) examined. Of these 17, 8 demonstrated CGD-associated chorioretinal lesions in at least one eye on histopathology. Of these 8, 7 showed amplification of 16S ribosomal DNA within the lesion; of these 7, two also amplified S. epidermidis and one P. aeruginosa. One had no bacterial DNA amplified. Importantly, no microbial DNA was amplified from the normal, non-lesional ocular tissues of these 8 cases. Furthermore, only 1 of the 9 eyes without chorioretinopathy had amplified Burkholderia DNA, that patient had a history of Burkholderia infection. CONCLUSIONS: We detected bacterial DNA in 7 of 8 (88%) cases with CGD-associated chorioretinopathy and only in 1 normal ocular tissue of 17 CGD cases. Bacterial infection may play a role in the pathogenesis of CGD-associated chorioretinal lesions.

Early degeneration of photoreceptor synapse in Ccl2/Cx3cr1-deficient mice on Crb1(rd8) background.

Photoreceptor ribbon synapse releases glutamate to postsynaptic targets. The synaptic ribbon may play multiple roles in ribbon synapse development, synaptic vesicle recycling, and synaptic transmission. Age-related macular degeneration (AMD) patients appear to have fewer or no detectable synaptic ribbons as well as abnormal swelling in the photoreceptor terminals in the macula. However, reports on changes of photoreceptor synapses in AMD are scarce and photoreceptor type and quantity affected in early AMD is still unclear. Here, we employed multiple anatomical techniques to investigate these questions in Ccl2⁻/⁻/Cx3cr1⁻/⁻ mouse on Crb1(rd8) background (DKO rd8) at one month of age. We found that approximately 17% of photoreceptors over the focal lesion were lost. Immunostaining for synapse-associated proteins (CtBP2, synaptophysin, and vesicular glutamate transporter 1) showed significantly reduced expression and ectopic localization. Cone opsins demonstrated dramatic reduction in expression (S-opsins) and extensive mislocalization (M-opsins). Quantitative ultrastructural analysis confirmed a significant decrease in the number of cone terminals and nuclei, numerous vacuoles in remaining cone terminals, reduction in the number of synaptic ribbons in photoreceptor terminals, and ectopic rod ribbon synapses. In addition, glutamate receptor immunoreactivity on aberrant sprouting of rod bipolar cells and horizontal cells were identified at the ectopic synapses. These results indicate that synaptic alterations occur at the early stages of disease and cones are likely more susceptible to damage caused by DKO rd8 mutation. They provide a new insight into potential mechanism of vision function lost due to synaptic degeneration before cell death in the early stages of AMD.

Enhanced apoptosis in retinal pigment epithelium under inflammatory stimuli and oxidative stress.

Age-related macular degeneration (AMD) is a neurodegenerative disease that causes irreversible central vision loss in the elderly. Retinal pigment epithelium (RPE) has been found to be a key component in AMD pathogenesis. The Ccl2(-/-)/Cx3cr1(-/-) (DKO) mouse on Crb1(rd8) background is created as an AMD model, developing AMD-like retinal lesions. Our study aimed to examine RPE apoptosis in DKO mouse and human ARPE-19 cell line. DKO RPE expressed higher apoptotic proteins when compared with age-matched wild type (WT) RPE in physiological conditions. Apoptosis of primary cultured mouse RPE was evaluated under stimulation with lipopolysaccharide for inflammatory stimulation and 2,3,7,8-tetrachlorodibenzo-p-dioxin or H(2)O(2) for oxidative stress. Compared with WT RPE, DKO RPE was more susceptible to Fas ligand (FasL)-mediated apoptosis under both inflammatory and oxidative stress, with less cell viability and higher expression of apoptotic transcripts and proteins. Decreased cell viability was also observed in ARPE-19 cells under each stimulus. Furthermore, we also investigated the anti-apoptotic effects of decoy receptor 3 (DcR3), a decoy receptor for FasL, on ARPE-19 cells under inflammatory and oxidative stress. DcR3 pre-incubated ARPE-19 cells showed decreased apoptosis, with increased cell viability and decreased expression of apoptotic transcripts and proteins under the stimuli. On the contrary, knockdown of DcR3 in ARPE-19 cells showed totally opposite results. Our study demonstrates that FasL-mediated RPE apoptosis may play a pivotal role in AMD pathogenesis.

Anti-inflammatory recombinant TSG-6 stabilizes the progression of focal retinal degeneration in a murine model.

BACKGROUND: Inflammatory responses are detected in the retina of patients with age-related macular degeneration and Ccl2-/-/Cx3cr1-/- mice on rd8 background,(Ccl2-/-/Cx3cr1-/- mice) a model that develops progressive age-related macular degeneration-like retinal lesions including focal photoreceptor degeneration, abnormal retinal pigment epithelium and A2E accumulation. Tumor necrosis factor-inducible gene 6 protein is an anti-inflammatory protein and has been shown to improve myocardial infarction outcome and chemically injured cornea in mice by suppressing inflammation. In this study, we evaluated the effect of an intravitreous injection of recombinant TSG-6 on the retinal lesions of Ccl2-/-/Cx3cr1-/- mice. METHODS: Recombinant TSG-6 (400 ng) was administered by intravitreous injection into the right eye of six-week-old Ccl2-/-/Cx3cr1-/- mice. Their left eye was injected with phosphate-buffered saline as a control. Funduscopic pictures were taken before injection and sequentially once a month after injection. The mice were killed two months after injection and the ocular histology examined. Retinal A2E, a major component of lipofuscin, was measured by high performance liquid chromatography. The microarray of ocular mRNA of 92 immunological genes was performed. The genes showing differentiated expression in microarray were further compared between the injected right eye and the contralateral (control) eye by [real-time quantitative reverse transcription polymerase chain reaction] qRT-PCR. RESULTS: The continuous monitoring of the fundus for two months showed a slower progression or alleviation of retinal lesions in the treated right eyes as compared with the untreated left eyes. Among 23 pairs of eyes, the lesion levels improved in 78.3%, stayed the same in 8.7% and progressed in 13.0%. Histology confirmed the clinical observation. Even though there was no difference in the level of A2E between the treated and the untreated eyes, microarray analysis of 92 immune genes showed that IL-17a was substantially decreased after the treatment. Expression of TNF-α showed a similar pattern to IL-17a. The results were consistent in duplicated arrays and confirmed by qRT-PCR. CONCLUSIONS: We concluded that intravitreous administration of recombinant TSG-6 might stabilize retinal lesions in Ccl2-/-/Cx3cr1-/- mice on rd8 background. Modulation of ocular immunological gene expressions, especially IL-17a, could be one of the mechanisms.

Evidence for enhanced tissue factor expression in age-related macular degeneration.

Tissue factor (TF) is the primary initiator of blood coagulation. In addition to hemostasis, TF can initiate intracellular signaling and promote inflammation and angiogenesis, the key processes underlying the pathogenesis of age-related macular degeneration (AMD). AMD, the leading cause of irreversible blindness among the elderly, involves many genetic and environmental risk factors, including oxidative stress and inflammation. In this study, TF expression was examined in human AMD tissue and in the eyes of a model of AMD, the Ccl2(-/-)/Cx3cr1(-/-) (DKO) mouse, as well as in the ARPE-19 cell line after lipopolysaccharide (LPS) and H(2)O(2) stimulation. Total RNA was extracted from tissue samples and further analyzed by real-time RT-PCR. Immunohistochemistry was performed to evaluate TF protein expression. In the human retina, a 32-fold increase of TF mRNA expression was detected in AMD macular lesions compared with normal maculae. TF protein expression was also enhanced in human AMD maculae. Similarly, TF transcript and protein expression were moderately increased in retinal lesions, neuroretinal tissue, and cultured RPE cells of DKO mice compared with age-matched wild-type mice. TF expression level correlated with age in both wild-type and DKO mice. In order to better understand how AMD might lead to enhanced TF expression, 1, 5, and 10 µg/ml LPS as well as 100 and 200 µM H(2)O(2) were used to stimulate ARPE-19 cells for 24 and 2 h, respectively. LPS treatment consistently increased TF transcript and protein expression. H(2)O(2) alone or in combination with LPS also moderately enhanced TF expression. These results indicate that upregulated TF expression may be associated with AMD, and inflammatory and oxidative stress may contribute to TF expression in AMD eyes.

Macrophage polarization in the maculae of age-related macular degeneration: a pilot study.

Macrophages can be polarized to exhibit either pro-inflammatory M1 or pro-angiogenic M2 phenotypes, but have high phenotypic plasticity. This pilot study investigated macrophage polarization in the macular retina and choroid of age-related macular degeneration (AMD) and non-AMD subjects, as well as in AMD choroidal neovascular membranes (CNVM). All specimens were evaluated for routine histopathology. Quantitative real-time polymerase chain reaction for representative M1 (CXCL11) and M2 (CCL22) transcripts were performed on macular choroidal trephines (MCT) of 19 AMD and nine non-AMD eye bank eyes, on the microdissected macular retinal cells from the archived slides of five geographic atrophic AMD, five exudative/neovascular AMD, and eight normal autopsied eyes, and on microdissected inflammatory cells from two surgically removed CNVM that did not respond to anti-vascular endothelial growth factor (VEGF) therapy. High M2-chemokine transcript and a low ratio of M1 to M2 chemokine transcript were found in aging non-AMD MCT. Advanced AMD maculae had a higher M1 to M2 chemokine transcript ratio compared to normal autopsied eyes. Macrophages in the two CNVM of patients unresponsive to anti-VEGF therapy were polarized toward either M1 or M2 phenotypes. The number of M2 macrophages was increased compared to M1 macrophages in normal aging eyes. A pathological shift of macrophage polarization may play a potential role in AMD pathogenesis.

Molecular biomarkers for the diagnosis of primary vitreoretinal lymphoma.

Primary vitreoretinal lymphoma (PVRL) or primary intraocular lymphoma, a subtype of primary central nervous system lymphoma, often masquerades as uveitis. The diagnosis of PVRL requires identification of lymphoma cells inside the eye, which is often challenging due to the frequent necrosis and admixing of PVRL cells with reactive lymphocytes. Therefore, detection of immunoglobulin heavy chain (IgH) and T-cell receptor (TCR) gene rearrangements provide molecular diagnosis of B- and T-cell lymphoma, respectively. We retrospectively evaluated 208 cases with a clinical diagnosis of masquerade syndrome from 1998 to 2010. In 200 cases with molecular analyses using microdissection and polymerase chain reaction, we found that 110 cases had IgH gene rearrangement, 5 cases had TCR gene rearrangement, and 85 cases were negative for these two gene arrangements. The molecular data corroborated the cytopathological diagnoses of PVRL and uveitis in the majority of cases. Cytokine above the detected levels in the specimens were also measured in 80 of the 208 cases. A ratio of vitreous IL-10 to IL-6 greater than 1, suggesting PVRL, was found in 56/80 cases; 53/56 had the correct diagnosis. A ratio less than 1, suggesting uveitis, was found in 24/80 cases; 17/24 correctly confirmed the diagnosis. Moreover, the molecular data corresponded well with the clinical course of the diseases. The sensitivity and specificity of these molecular biomarkers for the diagnosis of PVRL are higher than 95%.

A high omega-3 fatty acid diet reduces retinal lesions in a murine model of macular degeneration.

Age-related macular degeneration (AMD) is one of the leading cause of blindness among the elderly; however, current therapy options are limited. Epidemiological studies have shown that a diet that is high in omega-3 polyunsaturated (n-3) fatty acids can slow disease progression in patients with advanced AMD. In this study, we evaluated the effect of such a diet on the retinas of Ccl2(-/-)/Cx3cr1(-/-) mice, a model that develops AMD-like retinal lesions that include focal deep retinal lesions, abnormal retinal pigment epithelium, photoreceptor degeneration, and A2E accumulation. Ccl2(-/-)/Cx3cr1(-/-) mice that ingested a high n-3 fatty acid diet showed a slower progression of retinal lesions compared with the low n-3 fatty acids group. Some mice that were given high levels of n-3 fatty acids had lesion reversion. We found a shunted arachidonic acid metabolism that resulted in decreased pro-inflammatory derivatives (prostaglandin E(2) and leukotriene B(4)) and an increased anti-inflammatory derivative (prostaglandin D(2)). We also measured lower ocular TNF-alpha and IL-6 transcript levels in the mice fed a diet of high n-3 fatty acids. Our findings in these mice are in line with human studies of AMD risk reduction by long-chain n-3 fatty acids. This murine model provides a useful tool to evaluate therapies that might delay the development of AMD.

The effects of quercetin in cultured human RPE cells under oxidative stress and in Ccl2/Cx3cr1 double deficient mice.

Quercetin, a member of the flavonoid family, is one of the most prominent dietary antioxidants. This study investigates the mechanisms for the effects of quercetin on cultured human RPE cells and in Ccl2/Cx3cr1 double knock-out (DKO) mice, which spontaneously develop progressive retinal lesions mimicking age-related macular degeneration (AMD). In the in vitro experiment, cultured ARPE-19 cells were exposed to 1 mM H(2)O(2) with or without 50 muM quercetin for 2 h. Cellular viability, mitochondrial function, and apoptosis were assessed using crystal violet staining, MTT assay, and comet assay, respectively. Apoptotic molecular transcripts of BCL-2, BAX, FADD, CASPASE-3 and CASPASE-9 were measured by RQ-PCR. COX activity and nitric oxide (NO) level were determined in the supernatant of the culture medium. Quercetin treatment protected ARPE-19 cells from H(2)O(2)-induced oxidative injury, enhanced BCL-2 transcript levels, increased the BCL-2/BAX ratio, suppressed the transcription of pro-apoptotic factors such as BAX, FADD, CASPASE-3 and CASPASE-9, inhibited the transcription of inflammatory factors such as TNF-alpha, COX-2 and INOS, and decreased the levels of COX and NO in the culture medium. In the in vivo experiment, DKO and C57/B6 mice were treated with 25 mg/kg/day quercetin by intraperitoneal injection daily for two months. Funduscopy was performed monthly. After two months, serum was collected to measure NADP(+)/NADPH, COX, PGE-2, and NO levels. The eyes were harvested for histology and A2E measurement. Ocular transcripts of Bcl-2, Bax, Cox-2, Inos, Tnf-alpha, Fas, FasL and Caspase-3 were detected by RQ-PCR. Quercetin treatment did not reverse the progression of retinal lesions in DKO mice funduscopically or histologically. Although quercetin treatment could recover systemic anti-oxidative capacity, suppress the systemic expression of NO, COX and PGE-2, and decrease ocular A2E levels, it could not effectively suppress the transcripts of the ocular inflammatory factors Tnf-alpha, Cox-2 and Inos, or the pro-apoptotic factors Fas, FasL and Caspase-3 in DKO mice. Our data demonstrate that quercetin can protect human RPE cells from oxidative stress in vitro via inhibition of pro-inflammatory molecules and direct inhibition of the intrinsic apoptosis pathway. However, quercetin (25 mg/kg/day) does not improve the retinal AMD-like lesions in the Ccl2(-/-)/Cx3cr1(-/-) mice, likely due to its insufficient suppression of the inflammatory and apoptosis pathways in the eye.

Ocular involvement in nasal natural killer T-cell lymphoma.

PURPOSE: To describe the clinical, morphologic, and immunohistochemical features of a case of paranasal natural killer/T-cell lymphoma (NKTL) with ocular involvement. CASE REPORT: In March 2005 the patient presented with a maxillary sinusitis and upper nasal obstruction. In July she underwent a nasal computed tomography (CT) scan and multiple biopsies of the granulomatous tissue in the nasal fossae. The diagnosis was NK/T non-Hodgkin's lymphoma nasal type, stage IV A. Afterwards she presented anterior uveitis. In September after the diagnosis of lymphoma the patient underwent a bone marrow biopsy and thoracic and abdominal CT scan. An ophthalmic examination including visual acuity assessment and fundoscopic examination was made. In October she started chemotherapy cycles. Maxillary CT scan and ophthalmic examinations were performed during the cycles. In January 2006 after severe recurrences of panuveitis a diagnostic vitrectomy was performed. RESULTS: A diagnosis of T-lymphoma cells in the vitreous was made; the tumor was most likely originating from her paranasal NKTL. The condition of the patient deteriorated rapidly and she expired on February 2006. CONCLUSIONS: Nasal and paranasal sinus lymphomas are rare, but aggressive diseases with a tendency to invade tissues and spread to CNS, including the eye. Ocular manifestations prior to systemic ones may be useful to monitor the response to therapy.

The role of infectious agents in the etiology of ocular adnexal neoplasia.

Given the fact that infectious agents contribute to around 18% of human cancers worldwide, it would seem prudent to explore their role in neoplasms of the ocular adnexa: primary malignancies of the conjunctiva, lacrimal glands, eyelids, and orbit. By elucidating the mechanisms by which infectious agents contribute to oncogenesis, the management, treatment, and prevention of these neoplasms may one day parallel what is already in place for cancers such as cervical cancer, hepatocellular carcinoma, gastric mucosa-associated lymphoid tissue lymphoma and gastric adenocarcinoma. Antibiotic treatment and vaccines against infectious agents may herald a future with a curtailed role for traditional therapies of surgery, radiation, and chemotherapy. Unlike other malignancies for which large epidemiological studies are available, analyzing ocular adnexal neoplasms is challenging as they are relatively rare. Additionally, putative infectious agents seemingly display an immense geographic variation that has led to much debate regarding the relative importance of one organism versus another. This review discusses the pathogenetic role of several microorganisms in different ocular adnexal malignancies, including human papilloma virus in conjunctival papilloma and squamous cell carcinoma, human immunodeficiency virus in conjunctival squamous carcinoma, Kaposi sarcoma-associated herpes virus or human herpes simplex virus-8 (KSHV/HHV-8) in conjunctival Kaposi sarcoma, Helicobacter pylori (H. pylori,), Chlamydia, and hepatitis C virus in ocular adnexal mucosa-associated lymphoid tissue lymphomas. Unlike cervical cancer where a single infectious agent, human papilloma virus, is found in greater than 99% of lesions, multiple organisms may play a role in the etiology of certain ocular adnexal neoplasms by acting through similar mechanisms of oncogenesis, including chronic antigenic stimulation and the action of infectious oncogenes. However, similar to other human malignancies, ultimately the role of infectious agents in ocular adnexal neoplasms is most likely as a cofactor to genetic and environmental risk factors.

Ophthalmic manifestations, cytology, immunohistochemistry, and molecular analysis of intraocular metastatic T-cell lymphoma: report of a case and review of the literature.

We report a case of T-cell lymphoma metastatic to the eye, with an accompanying review of the literature. A 78-year-old white male with bilateral vitritis was diagnosed with primary cutaneous peripheral T-cell lymphoma unspecified, via vitreous biopsy. The tumor was found to be clonally related to the prior cutaneous malignancy using cytology, immunophenotyping, and molecular analysis. The vast majority of primary intraocular lymphomas are malignant B-cells, whereas intraocular T-cell lymphomas are uncommon. This case demonstrates the utility of immunophenotyping and molecular analysis with microdissection and polymerase chain reaction, as critical adjunctive studies, in patients presenting with a masquerade syndrome, and later diagnosed with T-cell intraocular lymphomas. Vitreo-retinal without uveal involvement in this case, similar to many ocular metastatic T-cell lymphomas reported in the literature, is particularly intriguing because the uvea, not retina, is the typical ocular tissue involvement in the majority of metastatic B-cell lymphomas.

Ccl2/Cx3cr1-deficient mice: an animal model for age-related macular degeneration.

BACKGROUND/AIMS: Senescent Ccl2-/- mice develop cardinal features of human age-related macular degeneration (AMD). Loss-of-function single-nucleotide polymorphisms within CX3CR1 are associated with AMD. METHODS: We generated Ccl2-/-/Cx3cr1-/- [double-knockout (DKO)] mice and evaluated the eyes using fundoscopy routine histology, immunochemistry, biochemistry and proteomics. RESULTS: At 6 weeks old, all DKO mice developed AMD-like retinal lesions such as abnormal retinal pigment epithelium cells, drusen, photoreceptor atrophy and choroidal neovascularization, which progressed with age and reversed with high omega-3 long-chain polyunsaturated fatty acid diet. N-retinylidene-N-retinylethanolamine (A2E), a major lipofuscin fluorophore, illustrated by an emission peak at approximately 600 nm, was significantly higher in DKO retinal pigment epithelium. Decreased ERp29 was found in the retina of DKO mice. CONCLUSION: A broad spectrum of AMD pathologies with early onset and high penetrance in these mice implicate certain chemokines, A2E and endoplasmic reticulum proteins in AMD pathogenesis.