Influence of platelet count on the expression of platelet collagen receptor glycoprotein VI (GPVI) in patients with acute coronary syndrome

Abstract

Platelets play a key role in the development of an acute coronary syndrome (ACS) and contribute to cardiovascular events. Platelet collagen receptor glycoprotein VI (GPVI) contributes significantly to platelet adhesion and thrombus formation in ACS. We consecutively investigated both the platelet count and the platelet surface expression of GPVI in 843 patients with a symptomatic coronary artery disease verified by coronary angiography. Four hundred fourteen patients presented with stable angina pectoris and 429 patients with ACS. Platelet surface expression of GPVI and CD62P was determined by flow cytometry and platelet count with a coulter counter, plasmatic soluble GPVI was measured by ELISA. Platelet GPVI expression in patients with ACS was compared to platelet count. Patients with ACS showed significantly elevated GPVI expression levels in the first and second quartiles of platelet count compared to patients with higher platelet count [mean fluorescence intensity (MFI) +/- standard deviation): 1(st) vs. 4(th): 20.44 +/- 6.1 vs. 18.62 +/- 3.7; p=0.012; 2(nd)vs.3(rd):21.2+/-8.5vs.18.76+/-3.7;P=0.03; 2(nd)vs.4(th): 21.2+/-8.5vs.18.62+/-3.7;P=0.004], which was paralleled in trend for the CD62P expression [MFI: 1(st) vs. 4(th): 11.2 +/- 6.8 vs. 12.3 +/- 9; p=0.057; 2(nd) vs. 3(rd): 16.3 +/- 16 vs.12.7 +/- 5.3; p=0.138; 2(nd) vs. 4(th): 16.3 +/- 16 vs.11 +/- 4.4; p=0.043]. In a subgroup of 48 patients with ACS, determination of soluble GPVI showed similar results [plasma GPVI (ng/ml): 1(st)vs.4(th): 1.6 +/- 0.6 vs. 1.2 +/- 0.4; p=0.046; 1(st) vs. 3(rd): 1.6 +/- 0.6 vs. 1.1 +/- 0.5; p=0.038; 2(nd) vs. 3(rd): 1.9 +/- 0.8 vs. 1.1 +/- 0.5; p=0.04; 2(nd) vs. 4(th): 1.9 +/- 0.8 vs. 1.2 +/- 0.4; p=0.056]. Thus, a lower platelet count comes along with a higher GPVI surface expression and plasma concentration in patients with ACS, which potentially reflects increased activation and enhanced recruitment of platelets to the site of vascular injury.

Value of Platelet Indices in Identifying Complete Resolution of Thrombus in Deep Venous Thrombosis Patients

“…Young et al [5] suggested that residual thrombus in DVT may be a marker for a generalized procoagulant diathesis. Higher thrombogenic state of the patients may be the possible mechanism responsible for platelet activation and MPVand PDW elevation in patients with RVT [19][20][21]. Large platelets are metabolically and enzimatically more active than small platelets.…”

Predictive Value of Mean Platelet Volume/Platelet Count for Prognosis in Acute Myocardial Infarction

“…The possible biological function for our finding may be as follows: higher MPV/PC ratio means higher MPV and lower PC; higher MPV reflects more thrombogenic and active platelets 6,7) and more severe inflammatory reactions; 30) lower PC related to higher expression of glycoprotein VI and inflammatory biomarkers in patients with acute coronary syndrome. 32,33) Considering these results presented, and the fact that MPV and PC are easily, cheaply, and routinely assessed parameters of a complete blood count, it is worth emphasizing the prognostic impact of MPV/PC ratio. Limitations: This study had several limitations.…”

Sandwich Immunoassay for Soluble Glycoprotein VI in Patients with Symptomatic Coronary Artery Disease

“…Subsequent studies showed that pGPVI may also be helpful as a biomarker for the early identification of an imminent myocardial infarction in patients with ambiguous electrocardiogram (ECG) and in patients with chest pain (6,7 ). Further research analyzed differences in pGPVI expression in atrial fibrillation as well as in platelet count (8,9 ). Apart from its predictive value, pGPVI may be used for the prediction of clinical outcome (10 ); moreover, we have shown that pGPVI may help to identify patients with transient ischemic attack or ischemic stroke (11 ).…”

“…Therefore, the development and validation of an ELISA or sandwich immunoassay would be desirable to reliably detect platelet-specific plasmatic soluble GPVI (sGPVI). Thus, we and others began to determine the concentration of sGPVI in smaller groups of patients (8,9,12,13 ).…”