Retinal hemangioblastoma vascular detail elucidated on swept source optical coherence tomography angiography.

PURPOSE: To report the distinct vascular pattern of a treatment-naïve retinal hemangioblastoma imaged on swept source optical coherence tomography angiography (SS-OCTA). OBSERVATIONS: A 33-year-old female with a history of Von Hippel-Lindau disease presented for follow-up of bilateral retinal hemangioblastomas. Ultra-widefield fundus photography of the left eye revealed a small, juxtapapillary lesion. SS-OCTA imaging centered at the lesion identified two distinct vascular foci. Centrally, the lesion was composed of a dense capillary meshwork. Peripherally, a pattern of branching vessels with terminal budding was identified. The patient was diagnosed with a new juxtapapillary retinal hemangioblastoma. CONCLUSIONS AND IMPORTANCE: SS-OCTA can visualize the in-vivo vascular structure of retinal hemangioblastomas. Early lesion identification can help in prompt diagnosis and monitoring. Further investigation is needed to assert if the branching and budding pattern described in this case report is broadly characteristic of this tumor entity.

The long-term effects of anti-vascular endothelial growth factor therapy on the optical coherence tomography angiographic appearance of neovascularization in age-related macular degeneration.

BACKGROUND: The short-term effects of anti-vascular endothelial growth factor (anti-VEGF) treatment on macular neovascularization (MNV) morphology is well described, but long-term studies on morphologic changes and correlation of such changes to the type of MNV have not been conducted. This study aims to determine if different types of MNVs in neovascular AMD (nAMD) behave differently with anti-VEGF treatment as visualized on optical coherence tomography angiography (OCTA). METHODS: Treatment-naïve nAMD patients were retrospectively screened for baseline and follow-up OCTA imaging 10 or more months after initial treatment. Images were graded for MNV type, area, activity, mature versus immature vessels, vessel density, presence of atrophy, atrophy location and area. Growth rate was calculated as the percent change in lesion area from baseline over the years of follow-up. In addition, the occurrence of complete regression and the percent of lesions that grew, remained stable, and shrunk per type was also evaluated. RESULTS: Forty-three eyes from 43 patients with a mean follow-up of 2 years were evaluated. On structural OCT, 26 lesions were classified as pure type 1 MNVs, 12 MNVs had a type 2 component, and 5 MNVs had a type 3 component. Of these cases, 2 mixed-type MNVs were considered to have completely regressed. There was no significant differences in MNV area and growth rate between type 1 and type 2 lesions, but all cases of type 3 lesions shrunk in the follow-up period. There was no correlation between the number of injections per year and growth rate, endpoint MNV area or endpoint activity status for any MNV type. There was no significant association between the development of atrophy and the number of injections, baseline MNV area, baseline vessel density, or lesion growth rate. CONCLUSIONS: In nAMD, complete regression of an MNV network exposed to anti-VEGF is rare. This work emphasizes the role of anti-VEGF as anti-leakage rather than vascular regression agents in nAMD.

Macular and Peripapillary Optical Coherence Tomography Angiography Metrics Predict Progression in Diabetic Retinopathy: A Sub-analysis of TIME-2b Study Data.

PURPOSE: To identify optical coherence tomography angiography (OCTA)-derived vessel metrics of the macula and optic nerve head (ONH) that predict diabetic retinopathy (DR) disease progression. DESIGN: Secondary analysis of clinical trial data. METHODS: This was a sub-analysis of prospectively collected data from 73 subjects that participated in the TIME-2b study (Aerpio Pharmaceuticals), a multicenter clinical trial for patients with moderate-to-severe DR treated with AKB-9778 and followed over a 12-month period. Eligible subjects were tested every 3 months with color fundus photography, spectral-domain OCT, and slit-lamp biomicroscopy. OCTA of the macula and ONH was obtained for a subset of patients enrolled at participating sites. En face, full-depth retinal projections centered at the macula were analyzed for multiple metrics including foveal avascular zone (FAZ) area and perimeter, nonperfusion area, vessel density (VD), and presence of intraretinal microvascular abnormalities (IRMA). VD of the radial peripapillary capillaries was evaluated in 4 quadrants surrounding the optic disc for ONH images. Progression was defined as a ≥2-step increase in DR severity scale score or development of diabetic macular edema. RESULTS: Over a follow-up period of 12 months, 15 of 73 (20.5%) subjects progressed. At pretreatment baseline, larger FAZ area, presence of IRMA, and reduced peripapillary VD in the superior temporal and inferior temporal regions were significantly associated with increased odds of progression. CONCLUSIONS: FAZ area and temporal peripapillary VD are predictors of DR progression. OCTA metrics may improve progression risk assessment in DR when compared to established risk factors alone.

RNA helicase DDX21 mediates nucleotide stress responses in neural crest and melanoma cells.

The availability of nucleotides has a direct impact on transcription. The inhibition of dihydroorotate dehydrogenase (DHODH) with leflunomide impacts nucleotide pools by reducing pyrimidine levels. Leflunomide abrogates the effective transcription elongation of genes required for neural crest development and melanoma growth in vivo1. To define the mechanism of action, we undertook an in vivo chemical suppressor screen for restoration of neural crest after leflunomide treatment. Surprisingly, we found that alterations in progesterone and progesterone receptor (Pgr) signalling strongly suppressed leflunomide-mediated neural crest effects in zebrafish. In addition, progesterone bypasses the transcriptional elongation block resulting from Paf complex deficiency, rescuing neural crest defects in ctr9 morphant and paf1(alnz24) mutant embryos. Using proteomics, we found that Pgr binds the RNA helicase protein Ddx21. ddx21-deficient zebrafish show resistance to leflunomide-induced stress. At a molecular level, nucleotide depletion reduced the chromatin occupancy of DDX21 in human A375 melanoma cells. Nucleotide supplementation reversed the gene expression signature and DDX21 occupancy changes prompted by leflunomide. Together, our results show that DDX21 acts as a sensor and mediator of transcription during nucleotide stress.