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Platelet-bound stromal cell-derived factor-1 (SDF-1) plays a crucial role in attachment of circulating CD34+ progenitor cells to the vascular wall, facilitating tissue healing after injury. However there is no evidence about expression of platelet-bound SDF-1 in patients with congestive heart failure (CHF). The aim of our study was to evaluate expression of platelet-bound SDF-1 and number of CD34+ progenitor cells in patients with CHF. Forty-eight patients with idiopathic dilated cardiomyopathy (DCM) and 61 patients with ischaemic cardiomyopathy (ICM) were consecutively enrolled into the study. Blood taken from 109 consecutive patients was studied for surface expression of platelet-bound SDF-1 and number of CD34+ progenitor cells by flow cytometry. The highest expression of platelet-bound SDF-1 was observed in patients with severe impairment of left ventricular systolic function compared with patients with mild or moderate impairment of left ventricular systolic function (mild vs. moderate vs. severe impairment of left ventricular systolic function: MFI ± SD: 35.6 ± 34 vs. 101.45 ± 73 vs. 124.86 ± 86.7, Kruskal-Wallis p < 0.001). Similar to platelet-bound SDF-1 number of CD34+ progenitor cells was the highest in severe impairment of left ventricular systolic function (mild vs. moderate vs. severe impairment of left ventricular systolic function: mean ± SD: 260.4 ± 177.5 vs. 580.7 ± 340.5 vs. 640.82 ± 370.6, Kruskal-Wallis p < 0.001). Platelet-bound SDF-1 expression was associated with number of circulating CD34+ progenitor cells ( r = 0.454, p < 0.001) in patients with CHF. Expression of platelet-bound SDF-1 and number of CD34+ cells were higher in patients with DCM compared with patients with ICM ( p < 0.001 for both) and inversely correlated with age and aspirin therapy. Platelet-bound SDF-1 and CD34+ progenitor cells are especially increased in patients with severe impairment of left ventricular systolic function in CHF. [ABSTRACT FROM AUTHOR]

Platelet collagen receptor glycoprotein VI (pGPVI) is elevated in patients with acute coronary syndrome (ACS) and ischemic stroke. Recently, we developed a novel bead-based sandwich immunoassay to determine soluble GPVI (sGPVI), which has been validated in ACS patients. This study aimed to evaluate the plasma levels of sGPVI and pGPVI expression in patients with suspected stroke. We consecutively evaluated 176 patients, who were admitted to the stroke unit. Surface expression of pGPVI was determined by flow cytometry, sGPVI concentrations were determined using our sandwich immunoassay. Unlike patients with TIA, patients with stroke showed significantly decreased plasma levels of sGPVI compared to patients with non-ischemic (NI) events (TIA: mean [µg/L] ± standard deviation): 6.1 ± 2.1 vs. NI: 8 ± 4; p = 0.192; stroke: 5.9 ± 2.3 vs. NI; p = 0.013), whereas for pGPVI, patients with TIA and ischemic stroke revealed a significantly increased platelet surface expression compared to NI patients (TIA: mean fluorescence intensity [MFI] ± standard deviation): 20.9 ± 5.4 vs. NI: 17.6 ± 5.2; p = 0.021; stroke: 20.3 ± 6.2 vs. NI; p = 0.016). Using logistic regression analysis, both sGPVI (p = 0.002) and pGPVI (p = 0.012) are independently associated with ischemic stroke compared to other laboratory markers. To predict the individual risk for ischemic stroke using the plasma levels of sGPVI, receiver operating characteristic (ROC) analysis determined an optimal cutoff value of sGPVI at 6.5 µg/l, thus, patients with decreased plasma levels (<6.5 µg/l) have a 1.5-fold adjusted odds ratio (95%confidence interval, 1.4-2.7). Lower plasma levels of sGPVI are associated with the slightly elevated risk of stroke and may be a promising novel biomarker. [ABSTRACT FROM AUTHOR]

Vascular lesion formation and collagen presentation are key events leading to the development of vulnerable plaques. Glycoprotein VI (GPVI) significantly contributes to plaque-associated collagen binding and thrombus formation. The aim of this study was to image endothelial injury using fluorescence-labelled GPVI-Fc (Fc, fragment crystallized), a soluble form of GPVI that was generated by cloning and fusing GPVI to an Fc-domain, in an ex-vivo rabbit model. This study serves as a proof-of-principle study to demonstrate that GPVI-Fc is a useful tool for detecting endothelial damage. The carotid and femoral arteries and the aorta abdominalis were isolated from rabbits and perfused with phosphate buffered saline (PBS) to remove all blood, and a catheter was placed into the vessels in situ. Endothelial damage was achieved by pulling an inflated balloon approximately 1 inch through the vessels, while control vessels were not balloon-treated. After balloon deflation, the catheter was removed. Fluorescence-labelled GPVI-Fc (50 µg/mL) was injected into the injured and control intact vessels, and the opened vessels were sealed by clamps. After incubation, the vessels were rinsed with PBS, and optical imaging was performed to measure GPVI-Fc binding to injured endothelium. The optical data corresponding to the mean detected optical signal of the regions of interest were corrected by subtracting the mean data of the background fluorescence (arbitrary units). After denudation, fluorescence was enhanced in injured femoral and carotid arteries when compared to intact femoral (41.1 ± 17.5 vs. 14.6 ± 6.5; P == 0.021) and carotid (30.2 ± 7.6 vs. 7.9 ± 3.9; P == 0.005) arteries. This preclinical GPVI-Fc-based vascular lesion imaging approach may be the first step towards a method that allows identification of vascular lesions in vivo. [ABSTRACT FROM AUTHOR]

Previous studies suggested that the adipocytokines, adiponectin and leptin, are associated with the progression and prognosis of coronary artery disease (CAD). The aim of this study was to differentially evaluate plasma levels of adiponectin and leptin in patients with CAD and their association with conventional laboratory parameters and markers of platelet activation. We consecutively evaluated 220 patients, who presented with a symptomatic CAD. Among these 83 (37.7%) presented with an acute coronary syndrome (ACS) and 137 (62.3%) with a stable angina pectoris (SAP). All patients have received coronary angiography. Baseline concentrations were determined by enzyme-linked immunosorbent assay (ELISA). Lower detection limits of the assay were 0.079 ng/mL for total adiponectin and 15.6 pg/mL for leptin. Patients with ACS showed significantly enhanced plasma levels of adiponectin and leptin compared with SAP (ACS vs. SAP (mean ± SD): adiponectin: 9.9 ± 7.6 µg/mL vs. 7.2 ± 5.7 µg/mL; P = 0.008; leptin: 20.9 ± 16.4 ng/mL vs. 15.2 ± 10.9 ng/mL; P = 0.012). However, a correlation between plasma total adiponectin and leptin levels has not been observed ( r = 0.038; P = 0.706). Plasma levels of total adiponectin and leptin positively correlated with C-reactive protein (adiponectin: r = 0.277; P = 0.001; leptin: r = 0.248; P = 0.007) and troponin-I (adiponectin: r = 0.219; P = 0.001; leptin: r = 0.190; P = 0.025). Plasma levels of both adipocytokines have shown an inverse correlation with markers of platelet activation such as platelet glycoprotein VI (adiponectin: r = −0.120; P = 0.048; leptin: r = −0.205; P = 0.036), and in a negative trend with P-selectin (adiponectin: r = −0.116; P = 0.073; leptin: r = −0.172; P = 0.078). To support our findings, we determined high-molecular-weight adiponectin in a subgroup of 37 patients, which showed similar results. Increased concentrations of total adiponectin and leptin were associated with ACS. Intriguingly, high plasma levels of both adipocytokines seem to modulate platelet activation. Further studies should elucidate the adipocytokine regulation in CAD. [ABSTRACT FROM AUTHOR]

Platelet-bound stromal cell-derived factor-1 (SDF-1) plays a crucial role in attachment of circulating CD34(+) progenitor cells to the vascular wall, facilitating tissue healing after injury. However there is no evidence about expression of platelet-bound SDF-1 in patients with congestive heart failure (CHF). The aim of our study was to evaluate expression of platelet-bound SDF-1 and number of CD34(+) progenitor cells in patients with CHF. Forty-eight patients with idiopathic dilated cardiomyopathy (DCM) and 61 patients with ischaemic cardiomyopathy (ICM) were consecutively enrolled into the study. Blood taken from 109 consecutive patients was studied for surface expression of platelet-bound SDF-1 and number of CD34(+) progenitor cells by flow cytometry. The highest expression of platelet-bound SDF-1 was observed in patients with severe impairment of left ventricular systolic function compared with patients with mild or moderate impairment of left ventricular systolic function (mild vs. moderate vs. severe impairment of left ventricular systolic function: MFI ± SD: 35.6 ± 34 vs. 101.45 ± 73 vs. 124.86 ± 86.7, Kruskal-Wallis p < 0.001). Similar to platelet-bound SDF-1 number of CD34(+) progenitor cells was the highest in severe impairment of left ventricular systolic function (mild vs. moderate vs. severe impairment of left ventricular systolic function: mean ± SD: 260.4 ± 177.5 vs. 580.7 ± 340.5 vs. 640.82 ± 370.6, Kruskal-Wallis p < 0.001). Platelet-bound SDF-1 expression was associated with number of circulating CD34(+) progenitor cells (r = 0.454, p < 0.001) in patients with CHF. Expression of platelet-bound SDF-1 and number of CD34(+) cells were higher in patients with DCM compared with patients with ICM (p < 0.001 for both) and inversely correlated with age and aspirin therapy. Platelet-bound SDF-1 and CD34(+) progenitor cells are especially increased in patients with severe impairment of left ventricular systolic function in CHF.