Thermal Analysis of Platelet Aggregation Assessed by Differential Scanning Calorimetry

摘要

Calorimetry is an analytical method that measures heat flow between a heat source and sample. The sample gains or losses heat based on physical or chemical composition. Differential scanning calorimetry (DSC) compares the results of heating a sample to those for heating a reference material. DSC then measures internal energy or a sample's calorific capacity. The aim of this study was to examine the thermal characteristics of platelet activation. Blood was obtained from human volunteers by venipuncture and collected in 5 ml siliconised and citronated vacutainer tubes. Platelet counts were measured using a hemocytometer. Platelet-rich (PRP) or platelet-poor plasma (PPP) was obtained by centrifugation. Ten microliters of PRP or PPP were placed into aluminum pans for DSC with or without activation by epinephrine (5.0 muM) or CaCI_2 (50 muM). To avoid a spontaneous activation of platelets samples were kept frozen, after a 5 min period of stabilization, 5 u.1 of aggregation-inducing agent was added. Scans were initiated at a -12degC after stabilization, with an increase of a 5degC/min to a maximum of 60degC. The experiments were performed on a TA Differential Scanning Calorimeter (New Castle, DE, USA). The difference in heat evolved between the PRP and PPP during the process of platelet activation was 253 J/g. The difference of heat flow in the activation of PRP versus PPP may correspond to an exothermic process involved in platelet aggregation.