Age related macular degeneration (AMD) is the most common cause of irreversible vision loss in the elderly. At present, there are an estimated one million people in Canada with some form of AMD and this number is expected to double to two million by 2031. These estimates are sobering, and it is predicted that costs for treatment and care of individuals who suffer vision loss from AMD will have significant impact on the social and public health systems in Canada in the next two decades. There are treatments to slow the progression of vision loss, but unfortunately, there are currently no cures available for AMD. In order to develop effective second generation therapies and cures, further insights into how and why AMD develops are greatly needed. Recent studies have provided novel insights into the role of inflammation in the pathogenesis of AMD. Inflammation, or swelling of the retinal tissues, causes harmful processes that promote macular degeneration. The proposed studies will focus on the triggers of inflammation in the retina. It is hypothesized that macular degeneration may be slowed or stopped by eliminating the molecules that cause inflammation in the retina. This study will focus on amyloid beta (Aβ), a toxic molecule that has been implicated in retinal inflammation, and the role that it may play in gene expression of the retinal pigment epithelial cell. Amyloid beta is a well studied peptide in another age related disorder, Alzheimer’s disease. It is the major extracellular deposit in Alzheimer’s disease plaques, and has recently been discovered as a component of drusen, the hallmark extracellular deposits in the retina of patients with the ‘dry’ form of AMD. These studies will allow the development of new treatment regimens that target retinal inflammation and thus minimize the processes that ‘trigger’ the onset of macular degeneration. / Medicine, Faculty of / Graduate

PURPOSE. Recessive mutations in CLN7/MFSD8 usually cause variant late-infantile onset neuronal ceroid lipofuscinosis (vLINCL), a poorly understood neurodegenerative condition, though mutations may also cause nonsyndromic maculopathy. A series of 12 patients with nonsyndromic retinopathy due to novel CLN7/MFSD8 mutation combinations were investigated in this study. METHODS. Affected patients and their family members were recruited in ophthalmic clinics at each center where they were examined by retinal imaging and detailed electrophysiology. Whole exome or genome next generation sequencing was performed on genomic DNA from at least one affected family member. Immunofluorescence confocal microscopy of murine retina cross-sections were used to localize the protein. RESULTS. Compound heterozygous alleles were identified in six cases, one of which was always p.Glu336Gln. Such combinations resulted in isolated macular disease. Six further cases were homozygous for the variant p.Met454Thr, identified as a founder mutation of South Asian origin. Those patients had widespread generalized retinal disease, characterized by electroretinography as a rod-cone dystrophy with severe macular involvement. In addition, the photopic single flash electroretinograms demonstrated a reduced b- to a-wave amplitude ratio, suggesting dysfunction occurring after phototransduction. Immunohistology identified MFSD8 in the outer plexiform layer of the retina, a site rich in photoreceptor synapses. CONCLUSIONS. This study highlights a hierarchy of MFSD8 variant severity, predicting three consequences of mutation: (1) nonsyndromic localized maculopathy, (2) nonsyndromic widespread retinopathy, or (3) syndromic neurological disease. The data also shed light on the underlying pathogenesis by implicating the photoreceptor synaptic terminals as the major site of retinal disease.

Age-related macular degeneration (AMD) is the leading cause of blindness inAmerica. The fact that AMD wreaks most of the damage in the center of the retina raises the question of whether light, integrated over long periods, is more concentrated in the macula. A method, based on eye-tracking, was developed to measure the distribution of light in the retina under natural viewing conditions. The hypothesis was that integrated over time, retinal illumination peaked in the macula. Additionally a possible relationship between age and retinal illumination was investigated. The eye tracker superimposed the subject’s gaze position on a video recorded by a scene camera. Five informed subjects were employed in feasibility tests, and 58 naïve subjects participated in 5 phases. In phase 1 the subjects viewed a gray-scale image. In phase 2, they observed a sequence of photographic images. In phase 3 they viewed a video. In phase 4, they worked on a computer; in phase 5, the subjects walked around freely. The informed subjects were instructed to gaze at bright objects in the field of view and then at dark objects. Naïve subjects were allowed to gaze freely for all phases. Using the subject’s gaze coordinates, and the video provided by the scene camera, the cumulative light distribution on the retina was calculated for ~15° around the fovea. As expected for control subjects, cumulative retinal light distributions peaked and dipped in the fovea when they gazed at bright or dark objects respectively. The light distribution maps obtained from the naïve subjects presented a tendency to peak in the macula for phases 1, 2, and 3, a consistent tendency in phase 4 and a variable tendency in phase 5. The feasibility of using an eye-tracker system to measure the distribution of light in the retina was demonstrated, thus helping to understand the role played by light exposure in the etiology of AMD. Results showed that a tendency for light to peak in the macula is a characteristic of some individuals and of certain tasks. In these situations, risk of AMD could be increased. No significant difference was observed based on age.

Orientador: Mônica Barbosa de Melo / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas / Made available in DSpace on 2018-08-28T01:54:14Z (GMT). No. of bitstreams: 1 Hirata_FabioEndo_M.pdf: 1885791 bytes, checksum: ccde99235ea9bbbcda8608e4c5aaf996 (MD5) Previous issue date: 2015 / Resumo: Introdução: A degeneração macular relacionada à idade (DMRI) é uma doença crônica degenerativa que afeta a área macular da retina causando diminuição da visão central. É a causa mais comum de perda visual irreversível nos países desenvolvidos. A DMRI é caracterizada pela presença de drusas, anormalidades do epitélio pigmentar da retina (EPR), atrofia geográfica, descolamento do EPR, neovascularização de coróide e cicatriz disciforme. Sua etiologia permanece pouco esclarecida, entretanto fatores genéticos associados a fatores ambientais possuem papel na etiologia e na progressão da doença. Dentre as variações gênicas, uma associação entre o polimorfismo Ala69Ser do gene LOC387715/ARMS2 ( rs10490924 C/T ) e o desenvolvimento da DMRI tem sido relatada em diferentes populações. Objetivo: O objetivo deste estudo foi avaliar se o polimorfismo rs10490924 está associado com a DMRI em uma amostra da população brasileira. Métodos: Cento e vinte e seis pacientes, sem parentesco, com DMRI (idade média de 74,17 ± 7,64) foram comparados com 86 controles saudáveis (idade média 71,82 ± 7,12). Os sujeitos do estudo foram classificados de acordo com o tipo de DMRI em DMRI seca e DMRI exsudativa. O polimorfismo LOC387715/ARMS2 rs10490924 foi avaliado através da reação em cadeia da polimerase e sequenciamento direto. Resultados: A frequência do alelo T foi significativamente maior em pacientes com DMRI do que nos controles (39,6% em comparação com 20,3%, p = 0,00002). O odds ratio (OR) para DMRI foi de 2,05 (IC95 % 1,09-3,89 ) para os heterozigotos (TG) e 8,45 ( IC95 % 2,21-37,82 ) para homozigotos (TT). Conclusões: Os resultados sugerem que há uma contribuição do SNP rs10490924 do gene LOC387715/ARMS2 para susceptibilidade à DMRI nesta amostra da população brasileira / Abstract: Introduction: Age-related macular degeneration (AMD) is a chronic degenerative disease that affects the macular area causing decreased central vision. It is the most common cause of irreversible vision loss in developed countries. It is characterized by the presence of drusen, abnormalities of the retinal pigment epithelium (RPE), geographic atrophy, RPE detachment, choroidal neovascularization, and disciform scar. The etiology of AMD remains poorly understood, but genetic factors associated with environmental factors have a role in the etiology and progression of the disease. Among the analyzed genetic variations, an association between LOC387715/ARMS2 (rs10490924) gene polymorphism and AMD has been reported in different populations. Purpose: The aim of this study was to evaluate whether this polymorphism is associated with AMD in a Brazilian cohort. Methods: A hundred and twenty six unrelated AMD patients (mean age 74.17 ± 7.64) were compared with 86 healthy controls (mean age 71.82 ± 7.12). Study subjects were classified according to the type of AMD in dry and wet AMD. The LOC387715/ARMS2 rs10490924 polymorphism was evaluated through polymerase chain reaction and direct sequencing. Results: The T allele frequency was significantly higher in AMD patients than controls (39.6% compared to 20.3%, p = 0,00002). The odds ratio (OR) for AMD was 2.05 (CI95% 1.09-3.89) for heterozygotes (TG) and 8.45 (CI95% 2.21-37.82) for homozygotes (TT). Conclusions: These results suggest that there is a contribution of the rs10490924 SNP of the LOC387715/ARMS2 gene to AMD susceptibility in this sample of Brazilian population / Mestrado / Oftalmologia / Mestre em Ciências Médicas

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Age-related macular degeneration (AMD) is one of the leading causes of blindness in adults over the age of 60. Currently, at least 11 million patients in the United States have some form of macular degeneration and this number is projected to grow as the population ages. The more severe form of the disease – neovascular (wet) AMD, is characterized by intraocular neovascularization, inflammation, and retinal damage; however, the disease progression can be deterred through intraocular injections of anti-angiogenic agents. The complications and burden that arise from repetitive injections as well as the difficulty posed by targeting the posterior segment of the eye make this an interesting territory for the development of novel drug delivery systems. New methods for drug delivery are being investigated exploring the use of nanoparticles and other polymeric materials. The goal of this project is to study the potential use of poly(lactide-co-glycolic acid)-polyethylene glycol (PLGA-PEG) nanoparticles in thermoreversible gels as localized sustained intraocular drug delivery. We prepared stable and reproducible corticosteroid-encapsulated nanoparticles in thermoreversible gels to inhibit vascular endothelial growth factor (VEGF) overexpression characteristic of neovascular AMD. We characterized the drug delivery system by obtaining size, shape, and drug encapsulation data. We also demonstrated that the polymer could be injected into the vitreous as a solution and transition to a gel phase based on the temperature difference between regular indoor environment and the vitreous body. The drug delivery system was tested on human retinal pigment epithelial cells (ARPE-19), for cytotoxicity, uptake and VEGF expression. We also examined the drug delivery system's ability to mitigate the disease progression in a mouse model of choroidal neovascularization (CNV). The effect on blood vessel area was shown and the changes in the mRNA expression of angiogenesis mediators were analyzed by real-time reverse transcription polymerase chain reaction (RT-PCR). These results indicate that the proposed drug delivery systems has the promise to be developed for retinal diseases, involving CNV, including neovascular AMD. Further studies are warranted in developing this promising intraocular drug delivery system for wet AMD and similar ophthalmic diseases. / Ph. D.

Yes / PURPOSE. To compare microperimetric sensitivity around the monocular preferred retinal locus (mPRL) in age-related macular degeneration (AMD) to normative data, and to describe the characteristics of visual field defects around the mPRL in AMD. METHODS. Participants with AMD (total n ¼ 185) were either prospectively recruited (n ¼ 135) or retrospectively reviewed from an existing database (n ¼ 50). Participants underwent microperimetry using a test pattern (37 point, 58 radius) centered on their mPRL. Sensitivities were compared to normative data by spatial interpolation, and conventional perimetric indices were calculated. The location of the mPRL relative to the fovea and to visual field defects was also investigated. RESULTS. Location of mPRL varied approximately 158 horizontally and vertically. Visual field loss within 58 of the mPRL was considerable in the majority of participants (median mean deviation 14.7 dB, interquartile range [IQR] 19.6 to 9.6 dB, median pattern standard deviation 7.1 dB [IQR 4.8–9.0 dB]). Over 95% of participants had mean total deviation worse than 2 dB across all tested locations and similarly within 18 of their mPRL. A common pattern of placing the mPRL just foveal to a region of normal pattern deviation was found in 78% of participants. Total deviation was outside normal limits in this region in 68%. CONCLUSIONS. Despite altering fixation to improve vision, people with AMD exhibit considerable visual field loss at and around their mPRL. The location of the mPRL was typically just foveal to, but not within, a region of relatively normal sensitivity for the individual, suggesting that a combination of factors drives mPRL selection. / This report presents independent research funded by the NIHR

Yes / Purpose: Frequency-of-seeing (FoS) curves (psychometric functions) for perimetric stimuli have been widely used in computer simulations of new visual field test procedures. FoS curves for age-related macular degeneration (AMD) are not available in the literature and are needed for the development of improved microperimetry test procedures, which are of particular interest for use as clinical trial endpoints. Methods: Data were refitted from a previous study to generate FoS curves for 20 participants with AMD, each tested at nine locations within the central 10°. Stimulus parameters, background luminance and dB scale were matched to the MAIA-2 microperimeter, and stimuli were presented in a method of constant stimuli to build up FoS curves over multiple runs. FoS curves were fitted with a modified cumulative Gaussian function. The relationship between sensitivity and slope of fitted FoS curves was modelled by robust linear regression, producing models both with and without an eccentricity parameter. Results: FoS curves were satisfactorily fitted to data from 174 visual field locations in 20 participants (age 65–83 years, 11 female). Each curve was made up of a median of 243 (range 177–297) stimulus presentations over a median of 12 (range 9–32) levels. Median sensitivity was 25.5dB (range 3.8–31.4dB). The median slope (SD of fitted function) was 1.6dB (range 0.5–8.5dB). As in previous studies of other conditions, the slope of fitted FoS curves increased as sensitivity decreased (p<0.001). Conclusions: FoS are provided for participants with AMD, as well as models of the relationship between sensitivity and slope. These fitted models and data may be useful for computer simulation studies of microperimetry procedures. Full details of the fitted curves are provided as supporting information.

Yes / We investigated whether perceptual learning could be used to improve peripheral word identification speed. The relationship between the magnitude of learning and age was established in normal participants to determine whether perceptual learning effects are age invariant. We then investigated whether training could lead to improvements in patients with age-related macular degeneration (AMD). Twenty-eight participants with normal vision and five participants with AMD trained on a word identification task. They were required to identify three-letter words, presented 10° from fixation. To standardize crowding across each of the letters that made up the word, words were flanked laterally by randomly chosen letters. Word identification performance was measured psychophysically using a staircase procedure. Significant improvements in peripheral word identification speed were demonstrated following training (71% ± 18%). Initial task performance was correlated with age, with older participants having poorer performance. However, older adults learned more rapidly such that, following training, they reached the same level of performance as their younger counterparts. As a function of number of trials completed, patients with AMD learned at an equivalent rate as age-matched participants with normal vision. Improvements in word identification speed were maintained at least 6 months after training. We have demonstrated that temporal aspects of word recognition can be improved in peripheral vision with training across a range of ages and these learned improvements are relatively enduring. However, training targeted at other bottlenecks to peripheral reading ability, such as visual crowding, may need to be incorporated to optimize this approach. / This work was supported by a National Institute of Health Research (NIHR) Post Doctoral Fellowship awarded to ATA, an Age UK Studentship awarded to AJB, and a Wellcome Trust Career Development Fellowship awarded to BSW. This article presents independent research funded by the NIHR.