Project description:In patients with severe kidney disease AVF are surgically placed in order to create good access for hemodialysis. In these dialysis patients the failure rates of AVF can be as high as 24% within 6 months after surgery, causing ineffective dialysis and necessitating additional clinical interventions. The pathological processes known to lead to AVF failure are beginning to be unravelled include the formation of venous neointimal hyperplasia (VNIH), thrombosis (Chang et al. PMID 16105066), and venous stenosis (Kanterman et al. PMID7892454, Tang et al. 1998), resulting in a reduced blood flow through the fistula. We established a rat model for AVF failure in human kidney dialysis patients. The characterization of this model has been previously described (Globerman et al. 2011, PubmedID:22002501). In this model the AVFs are surgically constructed in the right leg by connecting the superficial epigastric vein SEV to the common femoral artery (CFA), resulting in exposure of the SEV to arterial pressure with pulsatile and low resistant flow patterns (Globerman et al. 2011, PMID22002501). In the present study we utilized this AVF model in order to assess the effects of arterialized flow, with consequent pathological changes of the vessel wall due to surgical AVF instalment, on the transcriptome of endothelium from the SEV. Within the SEV these pathologies of the vessel wall include the formation of NIH in the main branch, and stenosis in the side branches. By employing this rat model we assessed the changes of the endothelial transcriptome in relation to these pathologies in order to gain mechanistic understanding of the potential roles of venous endothelium in AVF failure, as well as to identify potential biomarkers preceding AVF failure. AVF surgery was performed on N=6 rats, and 13-14 days after surgery the rats were sacrificed. AVFs were extracted from the rats, and microarray transcriptome analyses were performed on luminal endothelial cells that isolated from four different sites of the AVF by employing Laser Capture Microdissection (LCM). These sites included (i) N=5 AVF sections of the superficial epigastric vein (SEV) with neointimal hyperplasia (NIH), (ii) N=3 AVF sections of SEV side branches with luminal stenosis, (iii), N=6 sections of the SEV located distally from a ligation thereby omitting exposure to arterialized flow and consequently preventing the development of NIH or stenosis, and (iv) N=3 sections of the AVF common femoral artery without signs of NIH or stenosis.

Project description:Rationale: Epicardial adipose tissue (EAT) has been independently associated with non-calcified, high-risk coronary plaques in low-to intermediate risk subjects. Recently, a bidirectional communication was shown between EAT and diseased coronary arteries. In high-risk patients it is unknown whether quantitative measures of EAT can capture, and which molecular players are involved in this mutual interplay. Objective: In a high-risk population, we aimed to determine how the volume of EAT is linked to coronary artery disease (CAD) and to identify potential EAT-deregulated pathways in CAD patients specifically related to coronary artery calcification (CAC). Methods and Results: In a prospective cohort of 574 degenerative severe aortic stenosis patients referred to cardiac surgery, we quantified fat depots by computed tomography (CT) and performed a comparative quantitative proteomics of thoracic fat, including EAT, mediastinal (MAT) and subcutaneous (SAT) adipose tissues. We did not find an independent association of EAT volume with the severity, distribution and complexity of coronary stenosis in invasive coronary angiography. Although, EAT volume was correlated with high CAC, its cardiovascular risk factors-adjusted association was not significant. Taking as reference non-CAD matched-patients and compared to MAT and SAT, EAT proteomic signature of CAD was characterized by up-regulation of pro-calcifying annexins (Annexin A2, ANXA2), fatty acid binding transporters (FABP4) and inflammatory signaling proteins, and by down-regulation of fetuin-A and redox state regulatory enzymes. In EAT, ANXA2 regulation was positively correlated with CAC. EAT gene expression studies confirmed overexpression of ANXA2 and FABP4 in CAD, but no expression of FETUA was detected. Compared with non-CAD, fetuin-A circulating levels were higher in CAD, whereas no fetuin-A pericardial fluid differences were found. Conclusions: In this high-risk cohort, EAT presented an imbalance of pro-calcifying, pro-inflammatory and lipid transporters mediators. These local EAT-mediated regulatory mechanisms were not reflected by the CT volume of EAT alone.

Project description:While our understanding of the single-cell gene expression patterns underlying the transformation of vascular cell types during the progression of atherosclerosis is rapidly improving, the clinical and pathophysiological relevance of these changes remain poorly understood. Single cell RNA sequencing (scRNAseq) data generated with SmartSeq2 (~8000 genes/cell) in nearly 19,000 single cells isolated during atherosclerosis progression in mice with human-like plasma lipoproteins and from humans with asymptomatic and symptomatic carotid plaques was clustered into multiple subtypes. For clinical and pathophysiological context, the advanced-stage and symptomatic subtype clusters were integrated with 135 tissue-specific (atherosclerotic aortic wall, mammary artery, liver, skeletal muscle, and visceral and subcutaneous, fat) gene-regulatory networks (GRNs) inferred from 600 coronary artery disease (CAD) patients in the Stockholm-Tartu Atherosclerosis Reverse Network Engineering Task (STARNET) study.Advanced stages of atherosclerosis progression and symptomatic carotid plaques were largely characterized by three smooth-muscle cells (SMC), and three macrophage (MP) subtype clusters with extracellular matrix organization/osteogenic (SMC), and M1-type pro-inflammatory/Trem2-high lipid-associated (MP) phenotypes. Integrative analysis of these 6 clusters with STARNET revealed significant enrichments of three arterial wall GRNs: GRN33 (MP), GRN39 (SMC) and GRN122(MP) with major contributions to CAD heritability and strong associations with clinical scores of coronary atherosclerosis severity (SYNTAX/Duke scores). The presence and pathophysiological relevance of GRN39 was verified in five independent RNAseq datasets obtained from the human coronary and aortic artery, and primary SMCs and by targeting its top-key drivers, FRZB and ALCAM, in cultured human vascular SMCs.By identifying and integrating the most gene-rich single-cell subclusters of atherosclerosis to date with a CAD framework of GRNs, GRN39 was identified and independently validated as being critical for the transformation of contractile SMCs into an osteogenic phenotype promoting advanced-stage, symptomatic atherosclerosis.

Dataset Information

The Stockholm Atherosclerosis Gene Expression (STAGE) study: Global Gene Expression data from coronary and carotid artery disease patients

Publications

Multi-organ expression profiling uncovers a gene module in coronary artery disease involving transendothelial migration of leukocytes and LIM domain binding 2: the Stockholm Atherosclerosis Gene Expression (STAGE) study.

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