The Relationship Between Platelet Concentration And Platelet Aggregation

With the development of our country's economy, people's material living standard is improving; the incidence of coronary heart disease and other thromboembolic diseases are increasing. This is a serious threaten to people's health. When the vulnerable plaque ruptures, the platelet is activated, causing the platelet adhesion, release, aggregation. In that station, the platelets can form white thrombus, and lead to form red thrombus in the vascular. The thrombosis lead to coronary artery stenosis or obstruction, then occur unstable angina pectoris or acute myocardial infarction in clinical. Not only in the formation of thrombosis platelet plays key role, but also in the occurrence of coronary heart disease, development and prognosis play very important role. Platelet volume and count are independent prognostic factors of coronary heart disease. Study found that in the people of the apparently healthy men who had a rapid aggregation had significantly increased coronary heart disease mortality. Platelet aggregation is an important physiological characteristic of platelet. Therefore evaluation of platelet aggregation in judging the prothrombotic state, prevention and monitoring treatment of coronary heart disease and prognosis are very important. Though there are many methods to detect platelet function, platelet aggregation remains the golden standard. Although platelet aggregation is affected by many factors, such as platelet concentration, volume, distribution width, but platelet aggregation is a functional detection that various factors on platelet function can be expressed as changes in platelet aggregation. It is combination manifestation of platelet activation, release reaction, membrane glycoprotein receptors, can reflect the state of platelet activation. In clinic and some studies, turbidimetric platelet aggregometry and impedance platelet aggregometry are the most extensive used methods in recent decades. Turbidimetric platelet aggregometry, due to the need through twice centrifuge to obtain Platelet-rich Plasma and Platelet-poor Plasma, so easy to lose some larger volume platelet and lead some adjustment platelet (eg, prostacyclin, cAMP) decomposition, finally cause the variation of platelet aggregation. Otherwise, some substances in blood sample may effect the result, such as hyperlipidemia and hemolytic.Objective: Platelet aggregation is influenced by platelet concentration. Most present study on platelet aggregation use the average platelet count or titrate the specimen to specific platelet count to exclude the impact of different platelet count on aggregation. In many domestic and foreign researches, PRP concentration was adjusted to 200×109platelets/L to detect platelet aggregation. What kind of relationship between platelet concentration and platelet aggregation? It is still unclear. One research showed that the platelet aggregation had no obvious difference when the platelet concentration was in the 200-600×109platelets/L, which was measured by turbidimetric platelet aggregometry. Some studies showed that the platelet count and aggregation rate was related.To study took whole blood impedance platelet aggregometry to research the relationship between the normal subject's platelet concentration and platelet aggregation.Method: The apheresis platelet as the research object, it was diluted into different concentrations to detect the platelet aggregation. The platelet was indued by different inducing agents. Platelet samples were from blood donors who were strict conform to national standards of health checks. The concentration of apheresis platelet was about 1280×109 platelets/L, a total of 30 samples. Every sample was diluted to four concentration groups: C1 group: 50×109platelets/L, C2 group:150×109platelets/L, C3group:300×109 platelets/L, C4group:600×109platelets/L; four inducers: adenosine diphosphate (terminal concentration: 10umol/L; 20umol/L), AA (terminal concentration: 0.5mmol/L), adrenaline (terminal concentration: 10ug/ml).This research used the whole blood impedance analyzer (Model 590), made by Chrono-Log Corporation, to detect the platelet aggregation of different platelet concentrations and records the maximum aggregation rate and aggregation curve. The datas were expressed as the mean value±standard deviation (SD). The overall comparison in each group was evaluated by Single factor ANOVA variance analysis. If it was statistically significant, the comparisons of any two concentrations in each group would be carried out, using Dunnet's T3 test. A p value of<0.05 was considered statistically significant.Result:Platelet aggregation rate of four different concentrations under four kind inducers were significantly different. Platelet aggregation increased with the concentration in any inducer. It is not a linear relationship. With the concentration increasing, the increasing of the platelet aggregation rate gradually decreased, particularly at the concentrations of 300×109platelets/ L and 600×109 platelets/ L. Using curve fitting method, including of quadratic equations fitting, logarithmic equations fitting, cubic equation fitting, the S-curve model curve, we found that platelet aggregation changes with the platelet concentration of Logarithmic relationship in which Y = b0 + b1㏑ X in each of the four inducers groups. Therefore, platelet aggregation changes with the platelet concentration of logarithmic relationship in normal population.Conclusion: Platelet aggregation and platelet concentration was dependent. It is not a line relationship. As the platelet concentration increased, the aggregation rate increases. However along with the increase in platelet concentration, platelet aggregation rate increases decline. We concluded that: platelet aggregation changes with the platelet concentration of logarithmic relationship in normal population.