Objective Assessment of the mobilization of non-hematopoietic very small embryonic-like stem cells (VSEL) in acute myocardial infarction (MI). Background Acute MI induces mobilization of bone marrow stem cells. Recently rare population of VSELs, expressing markers of embryonic pluripotent stem cells (PSC) was identified in adult murine bone marrow and human umbilical cord blood. Methods 31 pts with acute MI and 30 healthy subjects (CTRL) were enrolled. Blood was sampled on admission, after 24 hours and 5 days later. Erythrocytes were lysed and lin-CD45- VSELs were isolated using a live cell sorting system (FACSAria). Results In healthy subjects the median number of circulating VSEL was very low [0.8 (0-1.3] cells/μL. In acute MI VSELs were mobilized early [2.7 (0.2-3.9) cells/μL; p<0.001), and remained elevated after 24 hrs and 5 days [4.7 (0.2-6.4); p<0.003 and 2.6 (0.3-3.6) cells/μL; p<0.03, respectively). The mobilization of VSEL was significantly reduced in patients older than 50 years and with diabetes in comparison to younger and non-diabetic patients. Circulating VSELs were small (7-8 μm) and enriched in mRNA of PSC markers (Oct-4, Nanog), cardiac lineage (GATA-4, Nkx2.5/Csx, MEF2C) and endothelial (VE-cadherin) markers. The presence of PSC markers (Oct-4, SSEA-4) and chemokine receptor CXCR4 in circulating VSELs was confirmed at the protein level by immunofluorescent staining and ImageStream system (ISS) analysis. Conclusion Acute MI induced mobilization of very small embryonic-like stem cells expressing pluripotent markers, early cardiac and endothelial markers and chemokine receptor CXCR4.

Bone marrow-derived cells which may be involved in cardiac repair/regeneration after ischaemic injury must undergo mobilisation into peripheral blood with subsequent homing and engraftment into the target organ. Mobilisation of the heterogeneous population of stem/progenitor cells in endothelial injury or myocardial ischaemia has been described recently. The number of circulating stem/progenitor cells reflects the endothelial damage, and turnover may be a surrogate marker reflecting the burden of cardiovascular risk factors and prognostic markers in stable coronary heart disease and acute coronary syndromes. Acute coronary syndromes are associated with increased levels of inflammatory and haematopoietic cytokines which, in turn, can mobilise progenitor cells from the bone marrow. Myocardial infarction increases the number of endothelial progenitor cells and other less well-defined subpopulations, such as CD34/c-kit(+) and CD34/CXCR4(+) cells, which may take part in cardiac repair after ischaemic injury. Data on mobilisation of stem/progenitor cells in acute coronary syndromes are summarised here. Cell types, mechanisms of mobilisation, homing and engraftment are discussed and their relevance to clinical outcomes.

Very small embryonic-like cells (VSELs) are a population of stem cells residing in the bone marrow (BM) and several organs, which undergo mobilization into peripheral blood (PB) following acute myocardial infarction and stroke. These cells express markers of pluripotent stem cells (PSCs), such as Oct-4, Nanog, and SSEA-1, as well as early cardiac, endothelial, and neural tissue developmental markers. VSELs can be effectively isolated from the BM, umbilical cord blood, and PB. Peripheral blood and BM-derived VSELs can be expanded in co-culture with C2C12 myoblast feeder layer and undergo differentiation into cells from all three germ layers, including cardiomyocytes and vascular endothelial cells. Isolation of VSLEs using fluorescence-activated cell sorting multiparameter live cell sorting system is dependent on gating strategy based on their small size and expression of PSC and absence of hematopoietic lineage markers. VSELs express early cardiac and endothelial lineages markers (GATA-4, Nkx2.5/Csx, VE-cadherin, and von Willebrand factor), SDF-1 chemokine receptor CXCR4, and undergo rapid mobilization in acute MI and ischemic stroke. Experiments in mice showed differentiation of BM-derived VSELs into cardiac myocytes and effectiveness of expanded and pre-differentiated VSLEs in improvement of left ventricular ejection fraction after myocardial infarction.

1. Circulating EPC count at rest is comparable between subjects with premature atherosclerosis and healthy volunteers. 2. A single bout of physical exercise causes a significant increase in circulating EPC count in both groups, but the dynamics of exercise-induced EPC mobilisation is different, with delayed exercise-induced EPC mobilisation in subjects with premature CAD. 3. The extent of atherosclerotic coronary lesions does not influence circulating EPC count at rest.

Background: Diagnosis of myocardial infarction with non-obstructive coronary arteries (MINOCA) requires both clinical evidence of acute myocardial infarction (AMI) and demonstration of non-obstructive coronary arteries using angiography. We compared the clinical features, treatments, and three-year outcomes in patients with MINOCA and myocardial infarction with obstructive coronary artery disease (MI-CAD). Methods: We retrospectively analyzed data for 205,606 hospitalized patients with AMI. MINOCA was indicated as a working diagnosis in 6063 patients (2.94% of all AMI patients). For the control group we included 160,886 patients with MI-CAD. We evaluated the baseline characteristics, medication management options, outcomes, and readmission causes at 36 months follow-up. Results: Patients in the MINOCA group were younger. Females constituted a greater proportion of patients in the MINOCA group when compared to MI-CAD patients. STEMI during admission was diagnosed less frequently in the MINOCA group when compared to the MI-CAD group. All-cause mortality at 12 months was higher in the MINOCA group (10.94% vs. 9.54%, p < 0.001). At 36 months, there was no difference in the all-cause mortality rates (MINOCA 16.18% vs. MI-CAD 14.93%, p = 0.081). All-cause readmission rates were lower in the MINOCA group when compared to the MI-CAD group at both 12 months (45.19% vs. 54.33%, p < 0.001) and 36 months follow-up (56.42% vs. 66.66%, p < 0.001). Conclusions: This is the first description of the clinical features, treatments, and three-year outcomes in a large population of Polish patients. The main finding of this study was a relatively low rate of MINOCA, with high rates of adverse events both at 12 and 36 months follow-up.