A unique proteomic signature of extracellular vesicles secreted from mesenchymal stromal cells from epicardial fat of patients with and without ischemic heart disease - The 67th Annual Conference of the Israel Heart Society

Rafael Brzezinski ^1,2 Olga Tepper-Shaihov ^1,2 Nili Naftali-Shani ^1,2 Elchanan Zuroff ³ David Volvovitch ³ Sergei Amunts ³ Eilon Ram ³ Ehud Raanani ³ Ehud Grossman ⁴ Jonathan Leor ^1,2

¹Neufeld Cardiac Research Institute, Sackler Faculty of Medicine, Tel Aviv University, Israel
²Tamman Cardiovascular Research Institute, Leviev Heart Center, Sheba Medical Center, Israel
³Department of Cardiac Surgery, Sheba Medical Center, Israel
⁴Internal Medicine Wing and Hypertension Unit, Sheba Medical Center, Israel

Background: Obesity, adipose tissue and extracellular vesicles (EVs) have been linked to metabolic syndrome and cardiovascular disease. The role of EVs secreted from human mesenchymal stromal cells (hMSCs) from epicardial fat (eFat) in the pathogenesis of ischemic heart disease (IHD) has never been studied. We sought to characterize EVs from eFat-hMSCs of patients with and without IHD.

Materials and methods: We collected eFat specimens from 12 patients with (n=7) and without (n=5) IHD who underwent open heart surgery. We isolated and cultured hMSCs by enzymatic digestion and adherence to plastic. EVs were separated from the culture media by differential ultra-centrifugation. We assessed EV size and structure by electron microscopy and nanoparticle tracking analysis. Finally, we evaluated the proteomic profile of EVs from ischemic and non-ischemic patients (n=3) by mass spectrometry.

Results: eFat-hMSCs from ischemic patients, secreted higher amounts of small EVs (size range of 70-200 nm) compared with non-ischemic controls (Figure 1A+B). Proteomic analysis identified over 1,000 proteins inside isolated EVs with 13 proteins that were significantly differentially expressed between the two groups of patients, including apolipoprotein E, transforming growth factor –β and collagen α-1 (Figure 1C). We performed an enrichment analysis which showed that EVs from eFat-hMSCs of ischemic patients encapsulated functional protein networks that associate with immune activation. Unlike IHD patients, EVs from non-ischemic patients carried functional protein networks that regulate angiogenesis.

Conclusions: eFat-hMSCs of patients with IHD secrete higher amounts of small EVs with a unique proteomic signature related to immune activation. EVs derived from eFat-hMSCs should be further studied for their potential role in the initiation and progression of cardiovascular diseases, such as coronary artery disease, heart failure and arrhythmias.

Figure 1: