Background— Polymorphonuclear neutrophils (PMNs) have gained attention as critical mediators of acute coronary syndromes (ACS). Myeloperoxidase (MPO), a hemoprotein abundantly expressed by PMNs and secreted during activation, possesses potent proinflammatory properties and may contribute directly to tissue injury. However, whether MPO also provides prognostic information in patients with ACS remains unknown. Methods and Results— MPO serum levels were assessed in 1090 patients with ACS. We recorded death and myocardial infarctions during 6 months of follow-up. MPO levels did not correlate with troponin T, soluble CD40 ligand, or C-reactive protein levels or with ST-segment changes. However, patients with elevated MPO levels (>350 μg/L; 31.3%) experienced a markedly increased cardiac risk (adjusted hazard ratio [HR] 2.25 [1.32 to 3.82]; P =0.003). In particular, MPO serum levels identified patients at risk who had troponin T levels below 0.01 μg/L (adjusted HR 7.48 [95% CI 1.98 to 28.29]; P =0.001). In a multivariate model that included other biochemical markers, troponin T (HR 1.99; P =0.023), C-reactive protein (1.25; P =0.044), vascular endothelial growth factor (HR 1.87; P =0.041), soluble CD40 ligand (HR 2.78; P <0.001), and MPO (HR 2.11; P =0.008) were all independent predictors of the patient’s 6-month outcome. Conclusions— In patients with ACS, MPO serum levels powerfully predict an increased risk for subsequent cardiovascular events and extend the prognostic information gained from traditional biochemical markers. Given its proinflammatory properties, MPO may serve as both a marker and mediator of vascular inflammation and further points toward the significance of PMN activation in the pathophysiology of ACS.

Evaluation of patients with acute chest pain in emergency rooms is time-consuming and expensive, and it often results in uncertain diagnoses. We prospectively investigated the usefulness of bedside tests for the detection of cardiac troponin T and troponin I in the evaluation of patients with acute chest pain.

Background— Several studies have suggested that stem cells are present in the stroma-vascular fraction (SVF) of adipose tissue (AT). Methods and Results— To characterize the cell populations that compose the SVF of human AT originating from subcutaneous and visceral depots, fluorescence-activated cell sorter analysis was performed by use of fluorescent antibodies directed against the endothelial and stem cell markers CD31, CD34, CD133, and ABCG2. The freshly harvested SVF contained large numbers of CD34 ⁺ cells as well as cells expressing CD133 and ABCG2. Further analysis of the CD34 ⁺ cells revealed 2 CD34 ⁺ cell populations with differential expression of the endothelial cell marker CD31. Selection of the CD34 ⁺ /CD31 ⁻ cells by use of magnetic microbeads, followed by cell culture, demonstrated that this cell population could differentiate under appropriate conditions into endothelial cells. Moreover, in mouse ischemic hindlimb, intravenous injection of CD34 ⁺ /CD31 ⁻ cells was associated with an increase in the blood flow and the capillary density and an incorporation of the cells in the leg vasculature. Conclusions— Our data indicate the presence of a cell population within the SVF of human AT characterized as CD34 ⁺ /CD31 ⁻ exhibiting characteristics of endothelial progenitor cells. Therefore, human AT might represent a source of stem/progenitor cells useful for cell therapy to improve vasculogenesis in adults.