Eleni Konstantinou

PURPOSE To evaluate the utility of a high magnification module (HMM) lens to visualize retinal photoreceptors, nerve fiber layer (NFL) and superficial retinal vasculature in physiologic and pathologic retinal conditions. DESIGN Observational descriptive study. PARTICIPANTS Thirty-two subjects with normal and pathologic retina examinations METHODS: Normal and pathologic maculae were imaged in vivo using still and video HMM lens modes, with fixation and contrast adjustments to enhance visualization. HMM images were qualitatively classified based on structures identified as either good (photoreceptors [PR] seen), average (PR mosaic cannot be clearly visualized, retinal vessels and other retinal changes can be seen) or poor (no identifiable structures). Selected eyes were imaged with fundus photography, optical coherence tomography (OCT), OCT angiography (OCTA), indocyanine green angiography (ICGA) and fluorescein angiography (FA) for comparison for the pathologic maculae. MAIN OUTCOMES MEASURES Description of HMM module obtained macula images. RESULTS From 32 eyes imaged (16 normal and 16 pathologic retinas), 12 of 16 normal and 11 of 16 pathologic retinas demonstrated at least average image quality, in which retinal vasculature and landmarks can be visualized. The mosaic pattern of hexagonal shapes representing photoreceptors could not be resolved in the majority of pathologic retinas. For the retinas in which the photoreceptor mosaics were visualized (12 of 16 normal and 2 of 16 pathologic retinas) parafoveal mosaic patterns appeared denser with better image quality for all subjects compared to foveal photoreceptors. Difficulty in resolving the photoreceptors in the umbo, fovea, and peri-fovea was encountered, similar to what has been reported with adaptive optics (AO) devices. The NFL was seen as arcuate hyperreflective bundles. Flow was observed in the macular microvasculature. Poorly resolved photoreceptors and scattered hyperreflective foci were correlated with changes in the RPE in eyes with age-related macular degeneration or central serous chorioretinopathy. Macular striae were seen in eyes with epiretinal membrane. CONCLUSION In the majority of eyes irrespective of whether retinal pathology was present, it was challenging to obtain average quality (or better) images. In the few cases with good quality imaging, the parafoveal photoreceptor mosaic, vascular flow and various features of pathologic eyes could be visualized.

Previous literature assessing ocular hemorrhagic complications of anticoagulant/antiplatelet medications in routine clinical practice is limited. This study evaluates the prevalence of spontaneous ocular hemorrhagic events associated with anticoagulation/antiplatelet therapy. A retrospective study was performed to identify patients taking anticoagulants (rivaroxaban [Xarelto; Janssen Pharmaceuticals, Beerse, Belgium], bivalirudin [Angiomax; The Medicines Company, Parsippany, NJ], lepirudin [Refludan; Bayer HealthCare Pharmaceuticals, Berlin, Germany], dabigatran [Pradaxa; Boehringer Ingelheim, Ingelheim am Rhein, Germany], and argatroban) and antiplatelet agents (clopidogrel [Plavix; Bristol-Myers Squibb, New York City, NY], prasugrel [Effient; Lilly Medical, Indianapolis, IN], and ticagrelor [Brilinta; AstraZeneca, Cambridge, UK]) who presented for an eye examination. Location of hemorrhage, relevant systemic and ocular comorbidities, baseline demographics, and concomitant aspirin ...

Verteporfin (VP) was first used in Photodynamic therapy, where a non-thermal laser light (689 nm) in the presence of oxygen activates the drug to produce highly reactive oxygen radicals, resulting in local cell and tissue damage. However, it has also been shown that Verteporfin can have non-photoactivated effects such as interference with the YAP-TEAD complex of the HIPPO pathway, resulting in growth inhibition of several neoplasias. More recently, it was proposed that, another non-light mediated effect of VP is the formation of cross-linked oligomers and high molecular weight protein complexes (HMWC) that are hypothesized to interfere with autophagy and cell growth. Here, in a series of experiments, using human uveal melanoma cells (MEL 270), human embryonic kidney cells (HEK) and breast cancer cells (MCF7) we showed that Verteporfin-induced HMWC require the presence of light. Furthermore, we showed that the mechanism of this cross-linking, which involves both singlet oxygen and ra...

Background To examine the baseline morphological characteristics and alterations in intraretinal microvascular abnormalities (IRMAs) in response to anti-vascular endothelial growth factor (anti-VEGF) treatment, documented by optical coherence tomography angiography (OCTA) in diabetic eyes. Methods In this retrospective study, IRMAs were evaluated with multimodal imaging (fundus photography, fluorescein angiography, OCTA) in treatment-naïve diabetic eyes before and after anti-VEGF treatment for diabetic macular edema (DME) and/or proliferative diabetic retinopathy (PDR) and compared to diabetic control eyes with similar diabetic retinopathy (DR) severity that did not receive anti-VEGF therapy. The morphological characteristics of IRMAs on enface OCTA imaging were graded by masked readers at baseline, then after anti-VEGF therapy in treated eyes or after observation in control eyes. Characterization of interval changes in an IRMA were based on the following parameters: branching, vess...

PURPOSE To evaluate the repeatability and reproducibility of photoreceptor density assessment in healthy subjects imaged with the Heidelberg Spectralis High Magnification Module (HMM) with manual cell counting. DESIGN Precision study, evaluation of diagnostic test or technology. PARTICIPANTS Eleven eyes of eight subjects. METHODS Images were acquired using the Spectralis HMM by a single operator during two separate imaging sessions. The three highest-quality images of each eye from each session were selected for analysis and co-registered. For a subset of patients, a second operator acquired images in one session, and images with best quality were selected for analysis. Photoreceptor densities were obtained by manual counts in squares of 0.0625 mm2 located in the parafovea. Repeatability (intragrader and intrasession) and reproducibility (interoperator, intergrader and intersession) were assessed by calculating the intra-class correlation coefficient (ICC) from linear mixed effects models. Bland-Altman plots, coefficients of repeatability and Pearson's correlation results were reported. MAIN OUTCOME MEASURES Intragrader, intrasession, intersession, interoperator and intergrader ICC estimates, and its 95% confidence intervals, for photoreceptor density measurements in the parafovea. RESULTS Twenty-four eyes of thirteen healthy subjects were initially imaged. Of these, eleven eyes (45.83%) of eight subjects that had at least three acceptable images in each session were included in this study. Mean parafoveal photoreceptor density was 14,988 cells/mm2 (SD = 1403.15). Intragrader ICC was 0.84 (95% CI: 0.57, 0.95), intrasession ICC was 0.69 (95% CI: 0.17, 0.86), intersession ICC was 0.88 (95% CI: 0.53, 0.96), interoperator ICC was 0.70 (95% CI: 0, 0.95) and intergrader ICC was 0.22 (95% CI: 0, 0.71). CONCLUSION Images obtained with the HMM allow for photoreceptor mosaic visualization in the macular area, mainly in the parafovea. Although densities obtained are in accordance with other reported methods in the literature, variability within and between images of the apparent cell mosaic were observed and this study did not demonstrate high repeatability and reproducibility for quantitative assessments using the manual counting method.

Significance Extracellular tissue debris accumulates with aging and in the most prevalent central-vision-threatening eye disorder, age-related macular degeneration (AMD). In this work, we discovered that lysosome-associated membrane protein-2 (LAMP2), a glycoprotein that plays a critical role in lysosomal biogenesis and maturation of autophagosomes/phagosomes, is preferentially expressed in the outermost, neuroepithelial layer of the retina, the retinal pigment epithelium (RPE), and contributes to the prevention of ultrastructural changes in extracellular basolaminar deposits including lipids and apolipoproteins. LAMP2 thus appears to play an important role in RPE biology, and its apparent decrease with aging and in AMD specimens suggests that its deficiency may accelerate the basolaminar deposit formation and RPE dysfunction seen in these conditions.

The parasite Toxoplasma can cause birth defects and severe disease in immunosuppressed patients. Strain differences in pathogenicity exist, and these differences are due to polymorphic effector proteins that Toxoplasma secretes into the host cell to coopt host cell functions. The effector protein GRA15 of some Toxoplasma strains activates the nuclear factor kappa B (NF-κB) pathway, which plays an important role in cell death, innate immunity, and inflammation. We show that GRA15 interacts with TNF receptor-associated factors (TRAFs), which are adaptor proteins functioning upstream of the NF-κB transcription factor. Deletion of TRAF-binding sites in GRA15 greatly reduces its ability to activate the NF-κB pathway, and TRAF2 knockout cells have impaired GRA15-mediated NF-κB activation. Thus, we determined the mechanism for GRA15-dependent NF-κB activation.

Age related macular degeneration is the leading cause of blindness in the developed world. Although its precise cause remains elusive, dysfunction of the retinal pigment epithelium (RPE) and dysregulation of complement have been implicated in its pathogenesis. The goal of this study was to evaluate the role of an AMP-dependent kinase (AMPK) activator, 5-aminoimidazole-4-carboxamide riboside (AICAR), on tumor necrosis factor alpha (TNF-α) induction of complement factor B (CFB) in RPE cells. We found that AICAR inhibited TNF-α-induced CFB expression in ARPE-19 and human primary RPE cells in a dose-dependent fashion. Treatment of cells with dipyridamole, which blocks AICAR cellular uptake abolished these effects. In contrast, the adenosine kinase inhibitor, 5-iodotubericidin, which inhibits the conversion of AICAR to the direct activator of AMPK, ZMP, did not reverse the effects on TNF-α-induced CFB expression, suggesting AMPK-independent effects. Indeed, knockout of AMPK in RPE cells ...

Rationale Age-related macular degeneration (AMD) is the most prevalent form of irreversible blindness in the developed world. Aging, inflammation and complement dysregulation affecting the retinal pigment epithelium (RPE), are considered significant contributors in its pathogenesis and several evidences have linked tumor necrosis factor alpha (TNF-α) and complement component 3 (C3) with AMD. Acadesine, an analog of AMP and an AMP-activated protein kinase (AMPK) activator, has been shown to have cytoprotective effects in human clinical trials as well as having anti-inflammatory and anti-vascular exudative effects in animals. The purpose of this study was to evaluate if acadesine is able to suppress TNF-α induced C3 in RPE cells. Methods ARPE-19 and human primary RPE cells were cultured and allowed to grow to confluence. TNF-α was used for C3 induction in the presence or absence of acadesine. Small molecule inhibitors and siRNA were used to determine if acadesine exerts its effect via...

PURPOSE To report a rare case of Birt-Hogg-Dubé Syndrome (BHD) with progressive chorioretinopathy. METHODS Case report. RESULTS A 55-year-old woman presented with longstanding nyctalopia attributed to a congenital retinal dystrophy, but no prior genetic testing. Her posterior pole examination demonstrated retinal pigment epithelium (RPE) mottling with extensive macular drusen and paracentral chorioretinal atrophy, consistent with a fleck retinopathy. Her past medical history was remarkable for nephrectomy for unilateral renal malignancy, parotid tumors and thyroid nodules. Dark adaptation time was prolonged, and electroretinography (ERG) revealed abnormal waveforms with depressed amplitudes. Genetic testing confirmed a deletion mutation in the folliculin (FLCN) gene and was negative for other relevant mutations, including EFEMP1 responsible for autosomal dominant macular and peripapillary drusen in Doyne honeycomb retinal dystrophy and TIMP3 responsible for Sorsby Fundus Dystrophy. CONCLUSION BHD is a rare autosomal-dominant disorder with multi-systemic clinical manifestations caused by a mutation in the FLCN gene. Affected individuals are prone to renal and pulmonary cysts, renal cancer, and fibrofolliculomas. Reports on ocular manifestations of BHD include eyelid fibrofolliculomas, flecked chorioretinopathy, choroidal melanoma, choroidal melanoma with sector melanocytosis, and retinal pigment epithelial micro-detachments. In this case of BHD, we note a fleck retinopathy with bilateral chorioretinal atrophy, displaying a phenotype of extensive chorioretinopathy associated with impaired dark adaptation and ERG abnormalities. ABBREVIATIONS BHD: Birt-Hogg-Dubé syndrome; FLCN: Folliculin. RPE: retinal pigment epithelium; OD: Oculus dexter (right eye); OS: Oculus sinister (left eye). OU: Oculus uterque (both eyes); ERG: electroretinogram; mfERG: multifocal electroretinography. ffERG: full-field electroretinography; FAF: fundus autofluorescence; OCT: optical coherence tomography; FA: fluorescein angiography; DA: dark-adapted; LA: light-adapted; mTOR: mammalian target of rapamycin; EFEMP1: epithelial growth factor-containing fibulin-like extracellular matrix protein 1; VPS13B: Vacuolar Protein Sorting 13 Homolog B; AGBL5: AATP/GTP-Binding Protein Like 5; ALMS1: Alstrom Syndrome 1; COL1BA1: Collagen Type I Beta, Alpha Chain 1; PDE6A: Rod Phosphodiesterase 6-alpha; USH2A: Usherin 2a; VCAN: Versican; RP: Retinitis pigmentosa; AR: Autosomal recessive.