Plasma Exosome Profile in ST-Elevation Myocardial Infarction Patients with and without Out-of-Hospital Cardiac Arrest

Abstract

The identification of new biomarkers allowing an early and more accurate characterization of patients with ST-segment elevation myocardial infarction (STEMI) is still needed, and exosomes represent an attractive diagnostic tool in this context. However, the characterization of their protein cargo in relation to cardiovascular clinical manifestation is still lacking. To this end, 35 STEMI patients (17 experiencing resuscitated out-of-hospital cardiac arrest (OHCA-STEMI) and 18 uncomplicated) and 32 patients with chronic coronary syndrome (CCS) were enrolled. Plasma exosomes were characterized by the nanoparticle tracking analysis and Western blotting. Exosomes from STEMI patients displayed a higher concentration and size and a greater expression of platelet (GPIIb) and vascular endothelial (VE-cadherin) markers, but a similar amount of cardiac troponin compared to CCS. In addition, a difference in exosome expression of acute-phase proteins (ceruloplasmin, transthyretin and fibronectin) between STEMI and CCS patients was found. GPIIb and brain-associated marker PLP1 accurately discriminated between OHCA and uncomplicated STEMI. In conclusion, the exosome profile of STEMI patients has peculiar features that differentiate it from that of CCS patients, reflecting the pathophysiological mechanisms involved in STEMI. Additionally, the exosome expression of brain- and platelet-specific markers might allow the identification of patients experiencing ischemic brain injury in STEMI.

Keywords: ST-elevation myocardial infarction; brain-associated marker; exosomes; platelets; resuscitated out-of-hospital cardiac arrest.

Figure 1

Exosome concentration and dimension are different between CCS and STEMI patients. Exosomes were isolated from plasma of CCS (N = 32) and STEMI (N = 18) patients and analyzed by NTA. (a) Representative NTA traces of exosomes isolated from plasma of CCS and STEMI patients. (b,c) Analysis of exosome dimension (mode) (b) and concentration (number of particles/mL) (c) as assessed by NTA. For each box plot, the center line illustrates the median and box limits indicate the 25th and 75th percentiles. ** p < 0.01, *** p < 0.001.

Figure 2

Plasma exosomes of STEMI patients display a different expression of specific proteins. Plasma exosomes from CCS and STEMI patients were lysed, and the expression of selected proteins was investigated. (a–g) Densitometric quantification and representative images of Western blot analysis of GPIIb (a), VE-cadherin (b), troponin (c), ceruloplasmin (d), transthyretin (e), fibronectin (f) and galectin-3-binding protein (g). For each box plot, the center line illustrates the median and box limits indicate the 25th and 75th percentiles. ns: not significant, * p < 0.05, ** p < 0.01, *** p < 0.001.

Figure 3

Exosomes isolated from plasma of STEMI with out-of-hospital cardiac arrest (OHCA-STEMI) have a higher dimension compared to uncomplicated STEMI. (a) Representative NTA traces of exosomes isolated from plasma of uncomplicated STEMI (n = 18) and OHCA-STEMI (n = 17). (b,c) Analysis of exosome concentration (number of particles/mL) (b) and dimension (mode) (c) as assessed by NTA. For each box plot, the center line illustrates the median and box limits indicate the 25th and 75th percentiles. ns: not significant, * p < 0.05.

Figure 4

Plasma exosomes of OHCA-STEMI patients display a greater expression of platelet and brain-associated markers. (a–f) Densitometric quantification and representative images of Western blot analysis of GPIIb (a), VE-cadherin (b), fibronectin (c), ceruloplasmin (d), transthyretin (e) and PLP1 (f). For each box plot, the center line illustrates the median and box limits indicate the 25th and 75th percentiles. ns: not significant, * p < 0.05, ** p < 0.01.

Figure 5

ROC curve analysis of exosomes versus cardiovascular clinical manifestation. Receiver operating characteristic (ROC) curve analysis was used to evaluate the ability of exosome to discriminate between STEMI (overall) and CCS patients (a–e) and between OHCA-STEMI and uncomplicated STEMI (f,g) in terms of dimension (mode) (a), GPIIb (b–f), VE-cadherin (c), ceruloplasmin (d), transthyretin (e) and/or PLP1 (g). Areas under the curve (AUCs), p values for AUC differences, cut-off values, sensitivity, and specificity are reported.