The choroid is a key player in maintaining ocular homeostasis and plays a role in a variety of chorioretinal diseases, many of which are poorly understood. Recent advances in the field of single... Show moreThe choroid is a key player in maintaining ocular homeostasis and plays a role in a variety of chorioretinal diseases, many of which are poorly understood. Recent advances in the field of single-cell RNA sequencing have yielded valuable insights into the properties of choroidal endothelial cells (CECs). Here, we review the role of the choroid in various physiological and pathophysiological mechanisms, focusing on the role of CECs. We also discuss new insights regarding the phenotypic properties of CECs, CEC subpopulations, and the value of measuring transcriptomics in primary CEC cultures derived from post-mortem eyes. In addition, we discuss key phenotypic, structural, and functional differences that distinguish CECs from other endothelial cells such as retinal vascular endothelial cells. Understanding the specific clinical and molecular properties of the choroid will shed new light on the pathogenesis of the broad clinical range of chorioretinal diseases such as age-related macular degeneration, central serous chorioretinopathy and other diseases within the pachychoroid spectrum, uveitis, and diabetic choroidopathy. Although our knowledge is still relatively limited with respect to the clinical features and molecular pathways that underlie these chorioretinal diseases, we summarise new approaches and discuss future directions for gaining new insights into these sight-threatening diseases and highlight new therapeutic strategies such as pluripotent stem cell-based technologies and gene therapy. Show less
Galaris, G.; Thalgott, J.H.; Lebrin, F.P.G.; Birbrair, A. 2019
Hereditary hemorrhagic telangiectasia (HHT) is a genetic disorder characterized by multi-systemic vascular dysplasia affecting 1 in 5000 people worldwide. Individuals with HHT suffer from many... Show moreHereditary hemorrhagic telangiectasia (HHT) is a genetic disorder characterized by multi-systemic vascular dysplasia affecting 1 in 5000 people worldwide. Individuals with HHT suffer from many complications including nose and gastrointestinal bleeding, anemia, iron deficiency, stroke, abscess, and high-output heart failure. Identification of the causative gene mutations and the generation of animal models have revealed that decreased transforming growth factor-beta (TGF-beta)/bone morphogenetic protein (BMP) signaling and increased vascular endothelial growth factor (VEGF) signaling activity in endothelial cells are responsible for the development of the vascular malformations in HHT. Perturbations in these key pathways are thought to lead to endothelial cell activation resulting in mural cell disengagement from the endothelium. This initial instability state causes the blood vessels to response inadequately when they are exposed to angiogenic triggers resulting in excessive blood vessel growth and the formation of vascular abnormalities that are prone to bleeding. Drugs promoting blood vessel stability have been reported as effective in preclinical models and in clinical trials indicating possible interventional targets based on a normalization approach for treating HHT. Here, we will review how disturbed TGF-beta and VEGF signaling relates to blood vessel destabilization and HHT development and will discuss therapeutic opportunities based on the concept of vessel normalization to treat HHT. Show less
Preeclampsia is a syndrome of pregnancy characterised by hypertension and proteinuria and occurs in up to 5 percent of pregnant women. The pathophysiology of preeclampsia has not been fully... Show morePreeclampsia is a syndrome of pregnancy characterised by hypertension and proteinuria and occurs in up to 5 percent of pregnant women. The pathophysiology of preeclampsia has not been fully elucidated yet. The endothelium is known to play a key role in the pathogenesis and levels of vascular endothelial growth factor are decreased due to an angiogenic imbalance. In the first part of this thesis, genes associated with preeclampsia were investigated through meta-analysis; genes within the coagulation and immunology domains remained significantly associated with preeclampsia after meta-analysis. In the second and third part of this thesis, the possible role of a key regulator of coagulation and immunology on the endothelium, thrombomodulin, in preeclampsia was investigated in the placenta and the kidney. Diminished placental thrombomodulin expression was associated with the angiogenic imbalance of preeclampsia. Next, in the fourth part of this thesis the interplay between podocytes and endothelial cells in the glomerulus during the anti-angiogenic conditions in preeclampsia was reviewed. In the final part of this thesis the splicing pattern of vascular endothelial growth factor was investigated throughout different examples of glomerular disease. Show less
