Molecular And Immunopathology Of Experimental And Clinical Ocular Diseases

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We identify and topographically localize inflammatory, degenerative, and malignant cells, as well as their products in patient specimens and animal tissues. We analyze the cells and their products mainly by routine pathology, immunohistochemistry, and molecular pathology. The application of cutting-edge technology, such as microdissection combined with molecular techniques including PCR, RT-PCR, RQ-PCR and genotyping, allows us to provide more accurate pathological diagnosis (assessment) and pathogenesis of the disease. It also guides us in selecting the most appropriate treatment for patients. We learn a great deal about the mechanisms of different ocular diseases from various animal models. Using animal models, we can also assess the efficacy of different therapeutic agents for various ocular diseases. This helps us better understand disease mechanisms and select specific therapies targeting particular diseases for our patients. In FY2011, we accomplished the following in our research: 1. Molecular Pathology of Age-Related Macular Degeneration (AMD): AMD is the leading cause of vision loss among the elderly in the United States, and the number of individuals affected is expected to increase 50% by the year 2020. The pathology of AMD is characterized with the accumulation of drusen, RPE and photoreceptor degeneration, geographic atrophy, and/or exudation with choroidal neovascularization. While several risk factors, including age, race, smoking, and diet have been linked to AMD, the etiology and pathogenesis of the disease remain largely unclear. Treatment options for geographic atrophy AMD are extremely limited and for exudative/neovascular AMD include intravitreal injections of anti-vascular endothelial growth factor (VEGF). Current knowledge has revealed that AMD development is strongly influenced by genetic factors. We and other investigators have reported significant associations between AMD and single nucleotide polymorphisms in CFH, CX3CR1, and ARMS2/HtrA1 over the past few years. Growing evidence also suggests that inflammatory and immunological elements (e.g., macrophages and microglia), apoptosis, cholesterol trafficking, angiogenesis (e.g., VEGF expression), and oxidative stress (e.g., the role of mitochondria) play an important role in AMD development. In FY2011, using a duplex RT-PCR copy number genotyping approach, we evaluated copy number variations in 131 patients with exudative/neovascular AMD, but did not find definitive associations in 8 highly associated AMD candidate genes. We reported an increase of tissue factor expression in our murine model (Ccl2/Cx3cr1 double deficient mice) and human AMD lesions. We demonstrated that naloxone ameliorated retinal lesions of the Ccl2/Cx3cr1 double deficient mice via its inhibitory effect on microglia, and that AAV-5 mediated sFLT01 gene therapy arrested retinal lesions of these mice. In addition, we published a comprehensive review on the role of anti-inflammatory agents in AMD treatment. Conventional therapy that focuses solely on inhibiting angiogenesis may not be optimal because of the inflammatory involvement in AMD. Anti-inflammatory agents, which target specific inflammatory pathways and molecules, could be used as promising adjunct agents combined with anti-VEGF therapy for exudative neovascular AMD and potential therapies for geographic atrophy AMD. More studies are required to evaluate the efficacy and safety of the anti-inflammatory agents. 2. Ocular Lymphoma: We retrospectively reviewed a series of systemic metastatic retinal lymphoma cases at the NEI from 1991 to 2009. They had similar clinical presentations as primary vitreoretinal lymphoma. Systemic T-cell lymphomas that invade the retina and vitreous are more aggressive than systemic B-cell lymphoma. Molecular analysis is more useful than vitreous cytokine levels for the diagnosis of this metastasis. We reported ocular manifestations and pathology of adult T-cell leukemia/lymphoma associated with human T-cell lymphotropic virus type 1 (HTLV-1). 3. New Pathology and Pathogenesis of Ocular Diseases: We reported ophthalmic manifestations and histopathology including novel retinal degenerative findings of xeroderma pigmentosa. The new findings illustrate the role of DNA repair in protection of the eyes from UV damage and neurodegeneration of the retina. We conducted the first investigation of inflammatory cytokines and chemokines in 15 eyes with sympathetic ophthalmia (SO) and revealed predominant M1 macrophages in choroidal granulomas and Dalen-Fuchs nodules. High levels of Il-17 were expressed within granulomas and presence of Th1 in non-granulomatous inflammation. Targeting Th1, M1 and IL-17 may represent effective therapy for SO. 4. Experimental Models for Various Ocular Diseases: In collaboration with Drs. Caspi, Egwuagu, Hejtmancik, and Nussenblatt of the NEI, Drs. Robert Adelstein and Warren Leonard of NHLBI, Dr. Nicholas Restifo of NCI, Dr. Philip Murphy of NIAID, and Dr. Charles Venditti of NHGRI, different models and mechanisms of ocular inflammation and genetic diseases have been evaluated and published. The data is further described in the annual reports of these senior investigators.