Hereditary hemorrhagic telangiectasia (HHT), associated with brain arteriovenous malformations, is caused by a loss of function mutation in either the endoglin (HHT1) or activin receptor-like kinase 1 gene (ALK-1, HHT2). Endoglin heterozygous (Eng+/-)mice have been proposed as a disease model. To better understand the role of endoglin in vascular malformation development, we examined the effect of vascular endothelial growth factor (VEGF) hyperstimulation on microvessels in adult endoglin heterozygous (Eng+/-) mice using an adenoviral vector to deliver recombinant human VEGF165 cDNA (AdhVEGF) into basal ganglia. VEGF expression was increased in AdhVEGF mice compared with the AdlacZ and saline group (P < 0.05) and localized to multiple cell types (neurons, astrocytes, endothelial cells, and smooth muscle cells) by double-labeled immunostaining. VEGF overexpression increased microvessel count for up to 4 weeks in both the Eng+/+ and Eng+/- groups (Eng+/+ 185 +/- 14 vs. Eng+/- 201 +/- 10 microvessels/mm2). Confocal microscopic examination revealed grossly abnormal microvessels in eight of nine Eng+/- mouse brains compared with zero of nine in Eng+/+ mice (P < 0.05). Abnormal microvessels featured enlargement, clustering, twist, or spirals. VEGF receptor Flk-1 and TGF-beta receptor 1 (T beta R1) expression were reduced in the Eng+/- mouse brain compared with control. Excessive VEGF stimulation may play a pivotal role in the initiation and development of brain vessel malformations in states of relative endoglin insufficiency in adulthood. These observations are relevant to our general understanding of the maintenance of vascular integrity.
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Hereditary Hemorrhagic Telangiectasia (HHT) is a rare congenital disease in which fragile vascular malformations (VM) - including small telangiectasias and large arteriovenous malformations (AVMs) - focally develop in multiple organs. There are few treatment options and no cure for HHT. Most HHT patients are heterozygous for loss-of-function mutations affecting Endoglin (ENG) or Alk1 (ACVRL1); however, why loss of these genes manifests as VMs remains poorly understood.
View Article and Find Full Text PDFUnlabelled: Hereditary Hemorrhagic Telangiectasia (HHT) is a rare congenital disease in which fragile vascular malformations focally develop in multiple organs. These can be small (telangiectasias) or large (arteriovenous malformations, AVMs) and may rupture leading to frequent, uncontrolled bleeding. There are few treatment options and no cure for HHT.
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Key Laboratory of Epigenetics and Oncology, The Research Center for Preclinical Medicine, Southwest Medical University, Luzhou 646000, China.
Hereditary hemorrhagic telangiectasia (HHT), also called Rendu-Osler syndrome, is a group of rare genetic diseases characterized by autosomal dominance, multisystemic vascular dysplasia, and age-related penetrance. This includes arteriovenous malformations (AVMs) in the skin, brain, lung, liver, and mucous membranes. The correlations between the phenotype and genotype for HHT are not clear.
View Article and Find Full Text PDFEndoglin mutants retained in the endoplasmic reticulum exacerbate loss of function in hereditary hemorrhagic telangiectasia type 1 (HHT1) by exerting dominant negative effects on the wild type allele.
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Department of Genetics and Genomics, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, United Arab Emirates.
Hereditary hemorrhagic telangiectasia (HHT) is an autosomal dominant disorder affecting 1 in 5000-8000 individuals. Hereditary hemorrhagic telangiectasia type 1 (HHT1) is the most common HHT and manifests as diverse vascular malformations ranging from mild symptoms such as epistaxis and mucosal and cutaneous telangiectases to severe arteriovenous malformations (AVMs) in the lungs, brain or liver. HHT1 is caused by heterozygous mutations in the ENG gene, which encodes endoglin, the TGFβ homodimeric co-receptor.
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National Heart and Lung Institute, Imperial College London, London W12 0NN, UK.
Hereditary haemorrhagic telangiectasia (HHT) is a vascular dysplasia inherited as an autosomal dominant trait, due to a single heterozygous loss-of-function variant, usually in (encoding activin receptor-like kinase 1 [ALK1]), (encoding endoglin [CD105]), or . In a consecutive single-centre series of 37 positive clinical genetic tests performed in 2021-2023, a skewed distribution pattern was noted, with 30 of 32 variants reported only once, but c.1231C>T (p.
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