Project description:Loeys-Dietz Syndrome (LDS), caused by a spectrum of mutations in the TGF-β signaling cascade, leads to aggressive thoracic aneurysms. Given the ubiquitous nature of TGF-β signaling machinery, the exact cell type(s) responsible for initiation of LDS pathogenesis is poorly understood.
Project description:Loeys-Dietz Syndrome (LDS), caused by a spectrum of mutations in the TGF-β signaling cascade, leads to aggressive thoracic aneurysms. Given the ubiquitous nature of TGF-β signaling machinery, the exact cell type(s) responsible for initiation of LDS pathogenesis is poorly understood.
Project description:Loeys-Dietz Syndrome (LDS), caused by a spectrum of mutations in the TGF-β signaling cascade, leads to aggressive thoracic aneurysms. Given the ubiquitous nature of TGF-β signaling machinery, the exact cell type(s) responsible for initiation of LDS pathogenesis is poorly understood.
Project description:Loeys-Dietz syndrome (LDS) is a hereditary aneurysm disorder caused by mutations that impair transforming growth factor-β (TGF-β) signaling. Although LDS patients develop aneurysms throughout the arterial tree, the aortic root is a site of increased risk. In order to identify molecular determinants of this regional vulnerability, we investigated the transcriptional heterogeneity of vascular smooth muscle cells (VSMCs) in the aorta of Tgfbr1M318R/+ LDS mouse models by single cell RNA sequencing (scRNAseq) and spatial transcriptomics. Downregulation of transcripts coding for components of the extracellular matrix-receptor mechanosensing apparatus and upregulation of transcripts related to stress and inflammation were observed in all Tgfbr1M318R/+ VSMCs. However, regardless of genotype, a subset of Gata4-expressing VSMCs predominantly located in the aortic root intrinsically displayed a less differentiated, pro-inflammatory transcriptional profile. A similar population was also identified in a published scRNAseq dataset of the aorta of LDS patients via the Coordinated Gene Activity in Pattern Sets (CoGAPS)/ProjectR pipeline. Postnatal VSMC-specific Gata4 deletion resulted in reduced aortic root dilation in LDS mice, in association with decreased levels of Agtr1a and other pro-inflammatory regulators. We propose that widespread dysregulation of mechanosensitive pathways may act on regionally restricted factors that “prime” specific aortic locations to increased risk of aneurysm.
Project description:BackgroundLoeys-Dietz syndrome (LDS) is a connective tissue disorder that commonly presents with vascular abnormalities. Owing to the rarity and severity of the condition, consensus guidelines for aortic surgery thresholds vary. In addition, evaluation of coronary arteries in patients with LDS (either routinely or before aortic root surgery) remain undefined. In this case report, we discuss a patient with LDS who found to have an ectatic aortic root and a coronary artery aneurysm and discuss guidelines for evaluation and management in this patient population.Case summaryA 48-year-old woman was incidentally found to have a 45 mm ectatic aortic root during evaluation for a neck mass. As part of pre-operative evaluation for aortic root replacement, left heart catheterization revealed a left main coronary artery aneurysm. Family history revealed aortic aneurysms, sudden cardiac death, and tall height. Physical examination was notable for pectus excavatum and elongated limbs. Workup for inflammatory aetiologies of aortic root dilation was negative. Genetic testing revealed a heterozygous pathogenic TGBF3 variant, consistent with LDS Type 5. She subsequently underwent two-vessel coronary artery bypass, excision of her left main coronary artery aneurysm, and ascending aortic replacement.DiscussionIn this case, we describe a patient with LDS who was noted to have a coronary artery aneurysm, a rare finding in the initial presentation of disease. In addition, we examine guidelines regarding evaluation of management of aortic root disease and coronary aneurysms.
Project description:Loeys-Dietz syndrome (LDS) is a heritable disorder that presents with thoracic aortic aneurysm and/or dissection caused by a mutation in one of the transforming growth factor-B receptor or ligand genes. It is associated with widespread familial arterial aneurysm and rupture. We present a case of a 70-year-old male with a family history of heritable thoracic aortic aneurysm disease who presented to the emergency department with chest pain. His presenting electrocardiogram was significant for ST elevation in the inferior leads with complete heart block. Computed tomography-angiography was done to rule out aortic dissection, which was negative for aortic dissection but did reveal 3.9 cm infrarenal abdominal aortic aneurysm and 2.7 cm bilateral iliac artery aneurysms. He was then taken for invasive angiography and was found to have aneurysmal dilation of the entire right coronary artery measuring up to 6 mm with 100% occlusion secondary to thrombus in the distal segment. He was found to have obstructive disease in the left anterior descending artery and first and second obtuse marginals (OMs). Genetic testing performed confirmed a pathogenic mutation in the TGFBRI gene (TGFBRI c.934G > A p.Gly312Ser) consistent with the diagnosis of LDS. Although LDS is known to cause arterial aneurysms throughout the arterial tree, there have been no other cases of primary coronary aneurysms reported in this patient population. This case represents the first description of a patient with genetically confirmed LDS presenting with coronary artery aneurysm.