Single Cell Landscape of Epicardial Adipose Tissue in Patients with Coronary Artery Disease

Background: Animal studies have demonstrated the role of epicardial adipose tissue (EAT) in coronary artery disease (CAD). Since little is known about the cellular composition of EAT in CAD, we aimed to understand the differences in cell composition between CAD and non-CAD patients. Understanding the cellular composition on a single cell level and uncovering the roles of different cell types can add significant knowledge to the field.

Methods: We analyzed single nucleus (SN) RNA sequencing data from 17 EAT samples. Non-CAD patients undergoing cardiac surgery for aortic disease (n = 8) were compared with CAD patients undergoing coronary artery bypass grafting (CABG) (n = 9). Bioinformatic analysis was performed using the R-based software package Seurat. After filtering, more than 90000 nuclei were analyzed. The Seurat-package “NICHES” was used to understand cell-cell signaling. Cryosections were prepared from EAT of CAD (n = 6) and non-CAD patients (n = 6) and Movat’s pentachrome staining allowed to detect fibrotic tissue. We cultivated adipocytes, stromal cells, and macrophages of EAT from CAD (n = 8) and non-CAD patients (n = 6) and collected conditioned medium (CM) for further assays. NAMPT (Visfatin) in CM was analyzed by ELISA.

Results: EAT is composed of adipocytes (ADPC) (33%), macrophages (MP) (21%), epicardial stromal cells (EpiSC) (18%), lymphocytes (12%), endothelial cells (EC) (11%), smooth muscle cells (SMC) (4%), and epicardial epithelial cells (EPC) (1%). CAD patients had more EpiSC (p < 0.05) and a trend toward less ADPC. ADPC in cryosections of CAD-EAT exhibited signs of hypertrophy. Interestingly, CAD-EAT showed an increased fibrotic area (p < 0.05). Gene set enrichment analysis revealed terms related to inflammation (“TNFalpha pathway via NFKB”) for several cell types in the CAD-group. Inflammatory marker genes such as NAMPT (Visfatin), NFKB1 or ICAM1 were upregulated in CAD cell types (SN data). “NICHES” revealed increased ADPC-ADPC signaling of CAD patients despite a lower cell amount compared to non-CAD patients. MP-MP signaling was also increased in the CAD group. CM from CAD-ADPC contained more NAMPT than CM from non-CAD-ADPCs. No differences were observed for EpiSC and MP.

Conclusion: SN RNA analysis of EAT revealed a complex picture of the cellular composition in CAD patients and non-CAD patients. Upregulation of inflammatory markers was observed in several cell types within the CAD group, potentially playing a role in disease progression.

Publikationsverlauf

Artikel online veröffentlicht:
13. Februar 2024