NCK1/2 are specific mediators of migration in Pericytes and promising targets in ischemic retinopathies

The particular focus of my dissertation is on pericytes which are mural cells that surround capillaries and control angiogenesis and capillary barrier function. I investigate endothelial cell-derived platelet-derived growth factor-B (PDGF-B) signaling during sprouting angiogenesis in health and disease. With this, I show that “activated” α-SMA-expressing pericytes cover angiogenic sprouts and pathological neovascular tufts (NVTs) in a mouse model of oxygen-induced retinopathy. By genetic lineage tracing experiments, this work demonstrates that pericytes acquire α-SMA expression during pathological NVT formation. Pericyte depletion through inducible endothelial-specific knockout of the ligand Pdgf-b decreases this NVT formation, but also impairs revascularization. Moreover, I demonstrate that loss of Nck1 and Nck2 in mural cells prevents NVT formation and vascular leakage and promotes revascularization, suggesting NCK signaling as a potential target for the treatment of retinopathies

Longitudinal Comparison of Constant Artifacts in Optical Coherence Tomography Angiography in Patients with Posterior Uveitis Compared to Healthy Subjects

Background: Knowledge about artifacts in optical coherence tomography angiography (OCTA) is important to avoid misinterpretations. An overview of possible artifacts in posterior uveitis provides important information for interpretations. Methods: In this monocentric prospective study, OCTA images from a total of 102 eyes of 54 patients with posterior uveitis, and an age-matched control group including 34 healthy subjects (67 eyes), were evaluated (day 0, month 3, month 6). We assigned different artifacts to distinct layers. Various types of artifacts were examined in different retinal layers. The χ2 test for the comparison between the control and uveitis group and Cochran’s Q test for the longitudinal comparison within the uveitis group were used. Results: A total of 2238 images were evaluated; 1836 from uveitis patients and 402 from healthy subjects. A total of 2193 artifacts were revealed. Projection (812 [36.3%]), segmentation (579 [25.9%]), shadowing (404 [18.1%]), and blink artifacts (297 [13.3%]) were the most common artifact types. The uveitis group displayed significantly more segmentation artifacts and projection artifacts (p p > 0.1). Conclusions: The uveitis patients showed more segmentation and projection artifacts than the control group. Within the uveitis group, artifacts remained longitudinally constant in terms of artifact type and pattern. The artifacts therefore appear to be reproducible on an individual level