Coronary circulating mononuclear progenitor cells and soluble biomarkers in the cardiovascular prognosis after coronary angioplasty

Abstract Currently, there are no confident prognostic markers in patients with coronary artery disease (CAD) undergoing angioplasty. The present study aimed to explore whether basal coronary circulating Mononuclear Progenitor Cells (MPCs) and vascular injury biomarkers were related to development of major adverse cardiovascular events (MACEs) and may impact clinical prognosis. Methods The number of MPCs and soluble mediators such as IL‐1β, sICAM‐1, MMP‐9, malondialdehyde, superoxide dismutase and nitric oxide were determined in coronary and peripheral circulation. Prognostic ability for MACEs occurring at 6 months follow up was assessed by time‐to‐event and event free survival estimations. Results Lower coronary circulating MPCs subpopulations CD45+CD34+, CD45+CD34+CD133+CD184+, lower MMP‐9 and higher sICAM‐1 significantly associated with MACEs presentation and showed prognostic ability; while peripheral blood increase in malondialdehyde and decreased superoxide dismutase were observed in patients with MACEs. Conclusion Coronary concentration of biomarkers related with vascular repair, such as MPCs subpopulations and adhesion molecules, may predict MACEs and impact prognosis in patients with CAD undergoing angioplasty; whereas peripheral pro‐oxidative condition may be also associated.


| INTRODUC TI ON
Coronary ischemic injury induces early vascular repair mechanisms involving mobilization of cells with vascular repairing abilities like Mononuclear Progenitor Cells (MPCs) and production of soluble mediators of inflammation, remodelling and oxidative stress; with potential role as predictors of adverse cardiovascular events in patients with coronary artery disease (CAD) submitted to coronary angioplasty. 1,2 Intracoronary circulating biomarkers have been postulated as convenient, as they closer reflect vascular damage and repair. 3,4 However, characterization of coronary biomarkers in human studies has been scanty. 4,5 This study aimed to explore whether coronary MPCs and vascular injury biomarkers were related to the development of major adverse cardiovascular events (MACEs) and may have prognostic role in patients submitted to coronary angioplasty.

| Study design
Quasi-experimental, correlational, prospective and observational study, that complied with the ethical guidelines of the 1975 Declaration of Helsinki and approved by the local Institutional Committees (096.2014), registered ClinicalTrials. gov NCT03583047. All participants provided written informed consent.

| Study population and data collection
Fifty-two consecutive candidates for coronary angiography, between March 2015 and February 2017, because of current CAD (chronic stable angina and acute coronary syndrome, including unstable angina, STEMI and NSTEMI). Due to methodological strategy to study variables interactions, and considering 95% CI alpha = 0.05, our sample size render a beta of 0.32; suggesting a careful interpretation of data".
Clinical-Demographic data were collected during study enrollment.
High blood pressure, dyslipidemia and Diabetes Mellitus were defined according to JNC8, NCEP/ATPIII and ADA guidelines, respectively. 8,9
Patients received standard dual antiplatelet therapy previous to Percutaneous Coronary Intervention (PCI) and antiplatelet therapy continued for at least 1 year. For blood sampling, 5 mL coronary blood was collected before angioplasty from the closest location to the atheroma plaque. Brachial peripheral blood sample was also collected.

| Determination of circulating MPCs
Blood sample was submitted to density gradient to obtain lymphocytes, which were washed and fixed in 4% paraformaldehyde.

| RE SULTS
The study population was constituted by 52 patients, mean aged 67.6 years old (31 males, 21 females) whose demographic and clinical characteristics are summarized in Table 1   The study population was further grouped according to timeto-MACEs period; where not MPCs ( Figure 1A), but lower coronary values of sICAM-1 and superoxide dismutase ( Figure 1B) showed prognostic ability for earlier MACEs; whereas lower coronary MPCs (CD45 + CD34 + CD133 + and CD45 + CD34 + CD133 + CD184 + ) and higher concentration of sICAM-1 (dichotomized by the median values) demonstrated prognostic ability for MACEs-free survival ( Figure 1A and B, Kaplan-Meier). Peripheral blood biomarkers showed less significant prognostic performance.

| D ISCUSS I ON
The translational relevance of this study is highlighted by the role of whereas further clinical relevance of progenitor cells in the mentioned meta-analysis is suggested by risk attenuation in cases of acute heart ischemia and stent re-stenosis. 13 The role of soluble adhesion molecules as predictors of MACE and further adverse outcomes in patients submitted to PCI has been previously hypothesized. 7 Our finding of prognostic ability of sICAM-1 and MMP-9 confirms the clinical usefulness of biomarkers of inflammation and vascular repair in the outcomes of patients with ischaemic heart disease submitted to PCI.
In both cases, coronary circulating MPCs and soluble mediators of vascular injury, showed higher prognostic ability than their peripheral distribution. Only few studies have evaluated the potential of coronary sampling for heart diseases. 4

ACK N OWLED G EM ENTS
The authors acknowledge funding from Consejo Nacional para la Ciencia y Tecnología Grant S0008-2014-1 FOSSIS for the Project No. 233947.

CO N FLI C T O F I NTE R E S T
The authors confirm that there is no conflict of interest.