Human and murine fibroblast single-cell transcriptomics reveals fibroblast clusters are differentially affected by ageing and serum cholesterol.

AIMS: Specific fibroblast markers and in-depth heterogeneity analysis are currently lacking, hindering functional studies in cardiovascular diseases (CVDs). Here, we established cell-type markers and heterogeneity in murine and human arteries and studied the adventitial fibroblast response to CVD and its risk factors hypercholesterolaemia and ageing. METHODS AND RESULTS: Murine aorta single-cell RNA-sequencing analysis of adventitial mesenchymal cells identified fibroblast-specific markers. Immunohistochemistry and flow cytometry validated platelet-derived growth factor receptor alpha (PDGFRA) and dipeptidase 1 (DPEP1) across human and murine aorta, carotid, and femoral arteries, whereas traditional markers such as the cluster of differentiation (CD)90 and vimentin also marked transgelin+ vascular smooth muscle cells. Next, pseudotime analysis showed multiple fibroblast clusters differentiating along trajectories. Three trajectories, marked by CD55 (Cd55+), Cxcl chemokine 14 (Cxcl14+), and lysyl oxidase (Lox+), were reproduced in an independent RNA-seq dataset. Gene ontology (GO) analysis showed divergent functional profiles of the three trajectories, related to vascular development, antigen presentation, and/or collagen fibril organization, respectively. Trajectory-specific genes included significantly more genes with known genome-wide associations (GWAS) to CVD than expected by chance, implying a role in CVD. Indeed, differential regulation of fibroblast clusters by CVD risk factors was shown in the adventitia of aged C57BL/6J mice, and mildly hypercholesterolaemic LDLR KO mice on chow by flow cytometry. The expansion of collagen-related CXCL14+ and LOX+ fibroblasts in aged and hypercholesterolaemic aortic adventitia, respectively, coincided with increased adventitial collagen. Immunohistochemistry, bulk, and single-cell transcriptomics of human carotid and aorta specimens emphasized translational value as CD55+, CXCL14+ and LOX+ fibroblasts were observed in healthy and atherosclerotic specimens. Also, trajectory-specific gene sets are differentially correlated with human atherosclerotic plaque traits. CONCLUSION: We provide two adventitial fibroblast-specific markers, PDGFRA and DPEP1, and demonstrate fibroblast heterogeneity in health and CVD in humans and mice. Biological relevance is evident from the regulation of fibroblast clusters by age and hypercholesterolaemia in vivo, associations with human atherosclerotic plaque traits, and enrichment of genes with a GWAS for CVD.

A systematic review and meta-analysis of the cerebrovascular event incidence after transcatheter aortic valve implantation.

OBJECTIVE: Periinterventional stroke is one of the most feared potential complication, among patients treated with transcatheter aortic valve implantation (TAVI). The purpose of this review was to investigate the incidence of cerebrovascular events and the influence of postinterventional neurologic check-up in patients undergoing TAVI. METHODS: A systematic review and meta-analysis were conducted according to the PRISMA guideline. Three separate electronic searches of the public domains Medline and Clinicaltrials.gov were performed to identify the 30-day incidence of stroke within randomized controlled trials (RCTs) and registries for patients undergoing a TAVI procedure. A meta-analysis was conducted to evaluate the 30-day incidence of stroke within RCTs. Furthermore, we pooled the RCTs in which a scheduled neurological check-up was conducted or not to investigate the effect of this intervention. RESULTS: Twenty-three studies including 399,491 TAVI patients were included, 6370 from RCTs, 833 from cerebral-embolic protection device RCTs and 392,288 were adopted from registries. The mean 30-day incidence of stroke among all reviewed studies was 2.33%. In RCTs evaluating TAVI the pooled stroke incidence was 3.86%, among RCTs focused CEP the incidence was 6.36% and in registries the incidence was 2.29%. Ten RCTs conducted scheduled neurological check-ups, the incidence in these was 4.03% and among the remaining RCTs it was 2.47%. In the meta-analysis, the pooled 30-day stroke incidence was 3.61% (95% CI 2.57-4.79%). CONCLUSION: This systematic review demonstrates that the stroke incidences following TAVI differ strongly according to the study design and neurological follow-up. Intense neurological testing increases the incidence of a stroke after TAVI.