INTRODUÇÃO: O tratamento padrão estabelecido pelo Early Treatment Diabetic Retinopathy Study (ETDRS) para retinopatia diabética proliferativa (RDP), com ou sem edema macular clinicamente significativo (EMCS), é a panfotocoagulação com laser. Essa forma de tratamento reduz o risco de perda visual, mas não proporciona ganho de visão. O objetivo deste estudo é avaliar os efeitos do acetonido de triancinolona associado à panfotocoagulação na RDP. MÉTODOS: Realizou-se um ensaio clínico randomizado, prospectivo e aberto com portadores de RDP bilateral e simétrica, submetidos à panfotocoagulação com laser em ambos os olhos. Portadores de EMCS foram tratados com fotocoagulação focal na região macular no primeiro episódio da panfotocoagulação. A injeção intravítrea de acetonido de triancinolona (4 mg/0,1 ml) foi administrada aleatoriamente em um dos olhos (grupo estudo), após último episódio da laserterapia, e o contralateral foi adotado para comparação (grupo controle), sendo seguidos por 6 meses. Os parâmetros adotados para avaliar os efeitos terapêuticos foram: acuidade visual com melhor correção óptica (tabela do ETDRS), medidas de espessura central e de volume macular por meio da tomografia de coerência óptica e taxa de sangramento (hemorragia pré-retiniana ou vítrea). As potenciais complicações da droga foram avaliadas durante o seguimento (pressão intra-ocular, catarata, endoftalmite e pseudo-endoftalmite). RESULTADOS: Foram incluídos 28 (vinte e oito) indivíduos com diabetes melito tipo 2. Quanto ao EMCS, 22 olhos apresentaram no grupo estudo e 23, no grupo controle (p= 0,317). A média de idade foi de 61,36 ± 5,77 anos, com predominância do sexo ferminino (57,1%). A maioria era portadora de hipertensão arterial sistêmica (82,1%) e usuária de insulina (75,0%). Não houve diferença significante nas médias de número de disparos da panfotocoagulação e da fotocoagulação na região macular entre os grupos. Quanto à acuidade visual, o grupo estudo apresentou pior acuidade antes do tratamento em relação ao grupo controle (p= 0,040), não havendo diferença significativa na primeira semana do tratamento. Durante o seguimento, o grupo estudo evoluiu com melhora na acuidade visual no primeiro (p< 0,001), no terceiro (p< 0,001) e no sexto meses (p< 0,001) em relação ao controle. Em relação às medidas de espessura central e de volume macular, os grupos não apresentaram diferença significativa antes do tratamento, no entanto, o grupo estudo apresentou medidas significativamente menores na primeira semana, no primeiro, no terceiro e no sexto meses em relação ao controle. Quanto à taxa de sangramento, 9 olhos (32,1%) do grupo controle evoluíram com sangramento e nenhum do grupo estudo (p< 0,001). Os grupos apresentaram diferença na pressão intra-ocular apenas na primeira semana do tratamento, quando as medidas do grupo estudo foram maiores que as do controle (p< 0,05). Nenhum dos olhos apresentou catarata com indicação cirúrgica, endoftalmite ou pseudo-endoftalmite. CONCLUSÃO: Os resultados deste estudo sugerem que a injeção intravítrea de triancinolona é um procedimento seguro e pode melhorar o prognóstico funcional e estrutural da mácula em olhos com RDP submetidos a panfotocoagulação com laser. / INTRODUCTION: The gold standard treatment for proliferative diabetic retinopahty (PDR) with and without clinically significant macular edema (CSME), as stablished by the Early Treatment Diabetic Retinopathy Study (ETDRS), is panretinal photocoagulation (PRP). This treatment lowers the rate of severe vision loss, but does not increase vision. The aim of this study is to evaluate the efficacy and safety of triamcinolone acetonide associated to PRP for the management of PDR. METHOD: This is a prospective, randomized clinical trial for patients with bilateral and symmetrical PDR who had undergone PRP in both eyes. Patients who had CSME were treated with macular focal photocoagulation on the first episode of the PRP. Intravitreal injection of triamcinolone acetonide (4 mg/0.1 ml) was given to the study eye after the last episode of PRP and the fellow eye was used as control. Follow up was 6 months long. Best-corrected visual acuity (BCVA) using ETDRS charts, central macular thickness and macular volume as measured by the optical coherence tomography software, and the amount of bleeding (both preretinal and vitreous) were the parameters chosen to analyse outcome. Side effects of triamcinolone acetonide such as intraocular pressure, cataracts and severe inflammation, were also followed during the study. RESULTS: Twenty eight diabetes type 2 patients were included. Twenty two study eyes and 23 fellow eyes (controls) presented with CSME (p= 0.317). Mean age was 61.36 ± 5.77 years, with 57.1% females. Many patients had hypertension (82.1%) and used insulin (75.0%). There was no significant difference on the number of spots used for PRP or macular photocoagulation in between the groups. The study eyes had lower BCVA on baseline than the control eyes (p= 0.040). One week after the treatment, there was no difference on BCVA between the study and control eyes. During the follow up, the study group increased their BCVA on the first (p< 0.001), third (p< 0.001) and sixth month (p< 0.001) compared to control. Even thought there was no significant difference on central macular thickness and macular volume between groups on baseline, the study eyes had significant lower measurements on the first week and first, third and sixth months in comparison to controls. Nine control eyes (32.1%) had hemorrhages and none study eyes (p< 0.001). Injected eyes had higher intraocular pressure than controls on the first week of treatment (p< 0.05). None of the eyes developed cataracts that needed surgery, endophthalmits or severe inflammation. CONCLUSION: This study suggests intravitreal injection of triamcinolone is a safe procedure that increases funcional and anatomical prognosis of the macula in PDR eyes that underwent PRP.

INTRODUÇÃO: A retinopatia diabética (RD) é uma das complicações mais frequentes dos diabetes mellitus tipo 1 (DM1). Durante a hiperglicemia, as células endoteliais da retina são expostas a altas concentrações de glicose e são incapazes de conter seu influxo. Isso resulta na ativação de vias deletérias intracelulares que culminam com o aumento de espécies reativas de oxigênio (ROS) e lesão neuronal e vascular. O estado pró inflamatório e pró trombótico ativa vias pró-oxidantes como a da NADPH oxidase. O excesso de ROS não é devidamente tamponado pelas vias antioxidantes (tais como as vias da glutationa e da tiorredoxina) em situações de hiperglicemia crônica, o que contribui para perpetuar o dano. OBJETIVO: Caracterizar uma população de pacientes DM1 quanto ao grau de RD e analisar a associação desta complicação microvascular com cinco polimorfismo de um único nucleotídeo (SNP) em genes pertencentes a vias pró- e antioxidantes. MÉTODOS: Pacientes acompanhados no ambulatório de diabetes de dois hospitais terciários do estado de São Paulo foram submetidos a fotos digitais do fundo de olho que incluíam os sete campos padronizados no estudo Early Treatment Diabetic Retinopathy Study (ETDRS) ou a uma oftalmoscopia binocular indireta; ambos foram avaliados por um único oftalmologista em cada um dos hospitais. A genotipagem dos SNPs foi feita por reação em cadeia de polimerase após transcrição reversa com duas sondas marcadas para cada reação. Os seguintes SNPs foram estudados: rs713041 (gene GPX4), rs17883901 (gene GCLC), rs6610650 (gene CYBB), -675 T/A (gene CYBA) e rs7211 (gene TXNIP). Os dados clínicos foram coletados por consulta ao prontuário médico ou questionário. Foi utilizado o modelo de regressão logística nominal politômica, tendo como categoria de referência a ausência de RD (ARD) ou dicotômica, tendo como categorias de referência a ausência de RD proliferativa (RDP) ou ARD. Após correção de Bonferroni, um valor de p <= 0,02 foi considerado significante. RESULTADOS: Um total de 341 pacientes (62% mulheres; idade média de 35 [±11] anos; com 22 [±9] anos de duração do DM1 e HbA1c de 8,6% [±1,6]) foi incluído. A prevalência de RDP foi de 30%, enquanto 42% dos pacientes apresentavam RD não proliferativa (RDNP). Somente os SNPs cuja distribuição dos genótipos respeitou o equilíbrio de Hardy-Weinberg foram analisados. Após ajuste para potenciais fatores de confusão, a presença do alelo T no SNP rs713041 (+718 C/T) no GPX4 foi inversamente associada à prevalência de RDP em pacientes do sexo feminino, com um odds ratio (OR) de 0,36 (intervalo de confiança [IC] de 95% de 0,17 a 0,75; p = 0,007) na análise dicotômica de RDP versus ausência de RDP. A presença do alelo T no SNP rs17883901 (-129 C/T) no GCLC conferiu risco para RDP na análise politômica (OR de 4,23; IC 95% de 1,38 a 12,93; p=0,01) e conferiu risco para a presença de qualquer grau de RD na análise dicotômica (ARD versus RDNP + RDP; OR de 3,07; IC 95% de 1,22 a 8,95; p=0,02). Não houve associação entre o SNP rs6610650 (gene CYBB) e RD nessa população. CONCLUSÃO: Os SNPs funcionais rs713041 no GPX4 e rs17883901 no GCLC modularam a susceptibilidade a RD na população de pacientes com DM1 estudada / INTRODUCTION: Diabetic retinopathy (DR) is one of the most frequent complications of type 1 diabetes mellitus (T1D). During hyperglycemia, retinal endothelial cells are exposed to high glucose concentrations and are unable to contain their influx. This results in the activation of deleterious intracellular pathways that culminate with the increase of reactive oxygen species (ROS) and neuronal and vascular injury. The pro-inflammatory and prothrombotic state activates pro-oxidant pathways such as NADPH oxidase. The excess of ROS is not adequately buffered by the antioxidant pathways (such as glutathione and thioredoxin pathways) in situations of chronic hyperglycemia, which contributes to perpetuate the damage. OBJECTIVE: To characterize a population of T1D patients regarding DR degree and to analyze the association of this microvascular complication with five single nucleotide polymorphisms (SNP) in genes belonging to pro- and antioxidant pathways. METHODS: Patients followed at the diabetes outpatient clinic of two tertiary hospitals in the state of São Paulo were submitted to digital photos of the eye fundus that included the seven fields standardized in the Early Treatment Diabetic Retinopathy Study (ETDRS) or to binocular indirect ophthalmoscopy; both were evaluated by a single ophthalmologist in each one of the hospitals. SNP genotyping was performed by polymerase chain reaction after reverse transcription with two labeled probes for each reaction. The following SNPs were studied: rs713041 (GPX4 gene), rs17883901 (GCLC gene), rs6610650 (CYBB gene), -675 T/A (CYBA gene) and rs7211 (TXNIP gene). The clinical data were collected by consulting the medical chart or by questionnaire. The polytomous nominal logistic regression model was used, having as reference category the absence of DR (ADR) or the dichotomous nominal logistic regression model was used, having as reference categories the absence of proliferative DR (PDR) or ADR. After Bonferroni correction, a p value <= 0.02 was considered significant. RESULTS: A total of 341 patients (62% female; mean age of 35 [± 11] years-old; diabetes duration of 22 [± 9] years and HbA1c of 8.6% [± 1.6]) was included. The prevalence of PDR was 30%, while 42% of the patients had non-proliferative DR (NPDR). Only SNPs whose distribution of genotypes respected the Hardy-Weinberg equilibrium were analyzed. After adjusting for potential confounding factors, the presence of the T allele at rs713041 (+718 C/T) in GPX4 was inversely associated with the prevalence of PDR in female patients, with an odds ratio (OR) of 0.36 (95% confidence interval [CI] 0.17-0.75; p = 0.007) in the dichotomous analysis of PDR versus absence of PDR. The presence of the T allele at rs17883901 (-129 C/T) in GCLC conferred risk for PDR in the polytomous analysis (OR of 4.23; 95% CI 1.38 to 12.93; p = 0.01) and for any degree of DR in the dichotomous analysis (ADR versus NPDR + PDR; OR of 3.07; 95% CI 1.22-8.95; p = 0.02). There was no association between the SNP rs6610650 (CYBB gene) and DR in this population. CONCLUSION: The functional SNPs rs713041 in GPX4 and rs17883901 in GCLC modulated the susceptibility to DR in the studied population of patients with T1D

The aim for this thesis was to identify prognostic factors for chronic diabetes complications that exist at the time of diabetes diagnosis. Low level of education (&lt;12 years) and low income (&lt;60% of median) was found to increase the risk to have high (&gt;70 mmol/mol) HbA1c at the time of diagnosis with 34 % and 35 %, respectively. Prevalence of diabetic retinopathy (DR) was 12% in a cohort of patients newly diagnosed with diabetes. Diabetic macular edema was present in 11% of patients with type 2 diabetes (T2D) and 13% of those with Latent Autoimmune Diabetes in Adults (LADA). Low beta cell function and low level of education increased the risk for DR with 110% and 43%, respectively. For every unit of increase in body mass index, the risk for DR was reduced by 3%. The cellular immunology of LADA patients was a mixture of that observed in both type 1 (T1D) and T2D patients. Compared to patients with T1D, LADA patients had more B-regulatory lymphocytes and antigen presenting cells capable of producing interleukine-35. This indicates a higher anti-inflammatory capacity in LADA patients compared to type T1D patients. By imputing age, body mass index, HbA1c at diagnosis, beta cell function and insulin resistance in a cluster analysis, five distinct diabetes clusters were identified. The four clusters representing T2D patients differed in incidence of DR, nephropathy and non-alcoholic fatty liver disease. This was replicated with similar results in three geographically separate populations. By studying socioeconomic background and factors present at the time of diagnosis we can better predict prognosis for chronic diabetes complications. These findings may facilitate better-targeted diabetes screening programs and more individually tailored treatment regimes.

Loss or partial loss of eye sight can have major effect on quality of person's life. One of the most common diseases, which causes loss or partial loss of eye sight are diabetic retinopathy and age releated macular degeneration. Both of these diseases can be prevented or mediated by early detection and proper treatment. The fundus camera, which is used to capture eye retina, has had major effect on increasing quality and speed of early detection. Images captured by fundus camera can be automatically analyzed in order to detect any possible signs of retina damage. This thesis proposes one possible way of automating this process. First part of this thesis describes eye, its diseases and capturing technology. Second part then proposes way of automating detection process and its implementation. Lastly, the results are evaluated.

Diabetic retinopathy and age-related macular degeneration are two of the most common retinal diseases in these days, which can lead to partial or full loss of sight. Due to it, it is necessary to create new approaches enabling to detect these diseases and inform the patient about his condition in advance. The main objective of this work is to design and to implement an algorithm for retinal diseases classification based on images of the patient's retina of previously mentioned diseases. In the first part of this work, there is described in detail each stage of each disease and its the most frequent symptoms. In this thesis, there is also a chapter about fundus camera, which is a tool for image creation of human eye retina. In the second part of this thesis, there is proposed an approach for classification of diabetic retinopathy and age-related macular degeneration. There is also a chapter about algorithmic methods which can be used for image processing and object detection in image. The last part of this thesis contains the test results and their evaluation. Assessment of success of proposed and implemented methods is also part of this chapter.

In this work I present conclusions of clinical-laboratory research focused on the patients with diabetic macular edema (DME). We performed biochemical and immunochemical analyses of vitreous samples that were collected during the pars plana vitrectomy. Moreover, at patients with non-proliferative diabetic retinopathy (NPDR) we assessed morphological characteristics of DME using optical coherence tomography (OCT). According to our findings, the vitreous and serum concentrations of uric acid and glucose were significantly higher in patients with diabetic retinopathy and DME compared to controls. Also total ratio (serum/ vitreous concentration) of uric acid and glucose was in diabetics significantly higher than in controls. The most important determinant of increasing concentration of both uric acid and glucose in the vitreous was the grade of diabetic retinopathy. Moreover, we demonstrated significant correlation between vitreous concentration of uric acid and concentration of the vascular endothelial growth factor (VEGF) in patients with DME and NPDR. We found further, that the volume of the macula (cube volume - CV) computed with the software of Cirrus HD-OCT correlates in diabetics significantly with the vitreous VEGF concentration, but not with uric acid. This OCT parameter could be used to...

Introduction: Relation of diabetes mellitus (DM) to the diabetic keratopathy and various stages of corneal nerve fiber damage has been well accepted. A possible association between changes in the cornea of diabetic patients and diabetic retinopathy (DR), DM duration, and age at the time of DM diagnosis were evaluated. Neuropathies are among the most common long-term complications of diabetes mellitus. Good glycemic control is essential in prevention of this complication. DM patients with similar mean glucose levels or glycated hemoglobin (HbA1c) levels often exhibit differences in evaluation of diabetic complications. One reason for these differences may be the differences in glucose variability. DM patients with similar mean glucose levels or HbA1c levels often exhibit differences in glucose variability Hypothesis: Diabetes mellitus damages the subbasal nerve fibers of the corneal and affects the density of epithelial, endothelial and stromal cells. Corneal changes in patients with DM are dependent on the degree of diabetic retinopathy (DR), age at diagnosis, duration of DM, and compensation parameters. Purpose: To compare changes in cell density in individual layers of cornea and status of subbasal nerve fibers in patients with type 1 DM (DM 1) and in healthy subjects. To evaluate the dependence...

Le système kallicréine-kinines est un système peptidergique complexe impliqué dans les processus inflammatoires, le contrôle du tonus et de la perméabilité vasculaire. Les effets biologiques des kinines sont accomplis par l’intermédiaire de deux types de récepteurs couplés aux protéines G, soit le récepteur B1 (B1R) et le récepteur B2 (B2R). Alors que le B2R est un récepteur constitutif, le B1R est faiblement exprimé en situation physiologique; il est induit par le stress oxydatif, les cytokines pro-inflammatoires (interleukine-1β (IL-1β) et le facteur de nécrose tumorale-α (TNF-α)) ou par des endotoxines bactériennes à la fois au niveau systémique et local, notamment dans la rétine. Des études récentes de notre laboratoire ont montré l’implication du B1R dans la pathogenèse et la progression de la rétinopathie diabétique et de la dégénérescence maculaire liée à l’âge (DMLA). Les objectifs des travaux présentés dans cette thèse consistent à déterminer : 1) le mécanisme par lequel le B1R est impliqué dans la rétinopathie diabétique chez le rat; 2) l’implication de la iNOS en aval dans la cascade inflammatoire activée par le B1R; 3) l’expression et la localisation cellulaire du B1R dans les rétines humaines atteintes de DMLA exsudative et atrophique. Nos résultats ont permis de démontrer une implication du B1R dans la rétinopathie diabétique via l’activation de l’enzyme de synthèse du monoxyde d’azote inductible (iNOS) dans un modèle de diabète de type 1 induit par la streptozotocine (STZ) chez le rat. En plus de sa localisation généralisée dans toute la rétine, le B1R est exprimé dans la couche de l’épithélium pigmentaire qui forme la barrière hémato-rétinienne externe. Les taux d’expression (protéique et ARNm) du B1R, de la iNOS, de la carboxypeptidase M (impliquée dans la biosynthèse des agonistes B1R), de l'IL-1β, du TNF-α, du facteur de croissance de l'endothélium vasculaire A (VEGF-A) et de son récepteur, le VEGF-R2, ainsi que des protéines nitrosylées augmentent à deux semaines dans la rétine diabétique. Ces augmentations ainsi que l’hyperperméabilité vasculaire rétinienne induite par le diabète et par l’injection intravitréenne d’un agoniste du B1R (R-838) sont bloquées par un inhibiteur de la iNOS (1400W) appliqué topiquement à la surface de l’œil pendant 1 semaine (premier article). Les résultats du deuxième article montrent une augmentation significative de l'immunoréactivité du B1R dans les rétines humaines prélevées de patients atteints de DMLA exsudative. Toutefois, les changements d’immunoexpression du B1R ne sont pas significatifs dans les rétines des patients atteints de DMLA atrophique. La réactivité des cellules gliales est plus marquée dans la forme exsudative que dans la forme atrophique de DMLA. Une colocalisation du B1R est observée avec des marqueurs des cellules de Müller, des astrocytes, de la microglie, de la iNOS et de la fibrose, suggérant une implication du B1R dans le processus inflammatoire et la formation de fibrose dans la DMLA exsudative. En revanche, l’expression du B2R demeure stable dans les rétines de DMLA exsudative et atrophique par rapport aux rétines témoins; ce résultat ne supporte pas la possibilité que ce récepteur puisse être impliqué dans la DMLA chez l’humain. / The kallikrein-kinins system is a peptidergic system involved in inflammatory processes, the control of the vascular tone and permeability. These effects are mediated by two G proteincoupled receptors, the Bradykinin type 1 (B1R) and type 2 (B2R) receptors. While the B2R is a constitutive receptor, B1R is almost undetectable in physiological condition; it is, however, induced by oxidative stress, pro-inflammatory cytokines (interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α)) or by bacterial endotoxins at both systemic and local levels, notably in the retina. Recent studies from our laboratory supported an implication of B1R in the pathogenesis and progression of diabetic retinopathy and age-related macular degeneration (AMD). This thesis aims at unraveling: 1) the mechanism by which B1R is involved in diabetic retinopathy in rats; 2) the involvement of iNOS in the inflammatory cascade downstream to the B1R; and, 3) the expression and cellular localization of B1R in human retinae with exudative and atrophic AMD. Our results have shown the implication of B1R in diabetic retinopathy via the activation of the inducible nitric oxide synthase (iNOS) in a type 1 model of diabetes induced by streptozotocin (STZ) in rats. In addition to its generalized localization throughout the retina, B1R is expressed in the retinal pigment epithelium which forms the outer blood-retinal barrier. The protein and transcript expression of inflammatory markers; iNOS, carboxypeptidase M, IL-1β, TNF-α, vascular endothelium growth factor A (VEGF-A) and its receptor, VEGF-R2, including B1R as well as nitrosylated proteins are increased in the retina of diabetic rats at 2 weeks post-STZ. These upregulations, as well as the retinal vascular hyperpermeability induced by diabetes and by the intravitreal injection of an B1R agonist (R-838) are blocked by a topical one-week treatment by eye-drop with the selective iNOS inhibitor (1400W) (first manuscript). The results of the second manuscript show significant increases in the immunoreactivity of B1R in exudative AMD retinae. Despite a slight increase, B1R immunostaining does not reach statistical significance in the retina of donors with atrophic AMD. The reactivity of glial cells is more impressive in the exudative than in the atrophic form of AMD. B1R is co-expressed with markers of Müller cells, astrocytes, microglia, iNOS and fibrosis, suggesting an involvement of B1R in the inflammatory events and the formation of fibrosis in exudative AMD. On the other hand, the expression of B2R remains stable in the retinae of exudative and atrophic AMD, supporting a secondary role of this receptor in AMD in humans.

In this work I present conclusions of clinical-laboratory research focused on the patients with diabetic macular edema (DME). We performed biochemical and immunochemical analyses of vitreous samples that were collected during the pars plana vitrectomy. Moreover, at patients with non-proliferative diabetic retinopathy (NPDR) we assessed morphological characteristics of DME using optical coherence tomography (OCT). According to our findings, the vitreous and serum concentrations of uric acid and glucose were significantly higher in patients with diabetic retinopathy and DME compared to controls. Also total ratio (serum/ vitreous concentration) of uric acid and glucose was in diabetics significantly higher than in controls. The most important determinant of increasing concentration of both uric acid and glucose in the vitreous was the grade of diabetic retinopathy. Moreover, we demonstrated significant correlation between vitreous concentration of uric acid and concentration of the vascular endothelial growth factor (VEGF) in patients with DME and NPDR. We found further, that the volume of the macula (cube volume - CV) computed with the software of Cirrus HD-OCT correlates in diabetics significantly with the vitreous VEGF concentration, but not with uric acid. This OCT parameter could be used to...

Indiana University-Purdue University Indianapolis (IUPUI) / Prevention of pathological angiogenesis is a key strategy for treatment of common blinding ocular diseases such as retinopathy of prematurity, proliferative diabetic retinopathy, and wet age-related macular degeneration. The current treatment strategies are associated with partial vision loss and are ineffective in a significant patient population. Hence novel drugs as well as new ways to target ocular angiogenesis are needed for treating these diseases. I pursued a natural antiangiogenic compound, cremastranone, to develop novel drug leads and to find new targets. The objective of my doctoral thesis project was to elucidate cremastranone’s molecular mechanism of action and optimize its structureactivity relationship (SAR). In order to achieve this goal, with the help of chemistry collaborators cremastranone was synthesized for the first time. I showed that cremastranone has 50-fold more potency against endothelial cells as compared to nonendothelial cells, and also tested a novel active isomer, SH-11052. By SAR studies I identified a potent molecule, SH-11037, that has 10-fold more selectivity against retinal endothelial cells as compared to macrovascular endothelial cells. I then elucidated cremastranone’s molecular mechanism using a chemical proteomic approach. I identified ferrochelatase (FECH) as a specific interacting protein partner of cremastranone using photoaffinity chromatography. Hence, I hypothesized that cremastranone exerts its antiangiogenic activities through modulation of the functions of FECH. Cremastranone inhibited the enzymatic activity FECH in endothelial cells. Therefore, I investigated the role of FECH in ocular angiogenesis. Partial loss of FECH, using a siRNA-based knock down approach, decreased retinal angiogenesis both in vitro and in vivo in mouse models. Knock down of FECH decreased the expression levels of key proangiogenic proteins HIF-1α, eNOS, and VEGFR2. This work suggests that ferrochelatase plays an important, previously undocumented role in angiogenesis and that targeting of this enzyme by cremastranone might be exploited to inhibit pathological angiogenesis in ocular diseases.