Effect of clopidogrel on platelet CD markers in normal individuals and in patients with untreated type 2 diabetes mellitus

The objective of this study was to evaluate the effect of clopidogrel response in patients with untreated type 2 diabetes mellitus as compared with normal individuals. One hundred and seven subjects i.e. 32 normal and 75 patients with untreated type 2 diabetes mellitus were enrolled in this study. In the first step, normal subjects as well as diabetic patients were selected and tested for various laboratory parameters and platelets flow cytometry. In the second step, an antiplatelet drug [clopidogrel] was administered for 10 days to each individual enrolled in the study. After 10 days blood samples were collected for platelets flow cytometry. CD41 and CD61 did not show any change after the administration of clopidogrel in resting and activated platelets. CD63 and CD62p positivity was increased in normal and in diabetic patients' platelets after activation with ADPbefore clopidogrel. It was decreased in normal resting and ADPstimulated platelets after clopidogrel treatment. CD63 and CD62p positivity in resting and ADP stimulated patients' platelets was also decreased after clopidogrel treatment. The change was, however, not as marked as in normal subjects

Platelet receptors: an instrumental of platelet physiology

Platelets play an important role in hemostasis, inflammation, host defense, tumor growth and metastasis. Platelets receptors are instrumental in platelet-platelet aggregation and interaction of platelets with leukocytes, endothelial cells and coagulation factors. These receptors are also the targets for antiplatelet drugs. This review focuses on the role of platelet receptors in human physiology. Data were extracted from peer-reviewed journals using MEDLINE and EMBASE databases, and the following terms [platelets, platelet receptors, CD markers, integrins, tetraspanins, transmembrane receptors, prostaglandin receptors, immunoglobulin superfamily receptors] were used

New horizons in platelets flow cytometry

Platelet flow cytometry is an emerging tool in diagnostic and therapeutic hematology. It is eminently suited to study the expression of platelet surface receptors both qualitatively as well as quantitatively. It can serve as a useful marker for the documentation of in vivo platelet activation, and thus, fore-warn the risk of thromboembolism in patients with diabetes mellitus, coronary syndromes, peripheral vascular diseases, and pre-eclampsia. This technique can also be extended to study and compare the effect of various antiplatelet drugs on the level of activation of platelets and to establish any dose-effect relationship of these drugs. Topographical localization of platelet granules and study of platelet-platelet and platelet-leukocyte interaction is also possible by this procedure. All these parameters serve as pointers towards the presence of activated platelets in the circulation with its thromboembolic consequences. This is a simple reliable and cost effective technique which has a wide application in the diagnosis of various inherited and acquired platelet disorders. Study of platelet cluster of differentiation (CD) markers in various inherited disorders i.e. Bernard Soulier’s disease, von Willebrand disease, Glanzman’s disease, and Grey platelet syndrome may help categories the molecular lesions in these oft under-studied disorders.

Flow cytometry based chronologic analysis of surface glycoproteins of resting and stimulated platelets in normal individuals

To evaluate the effect of timed incubation on the activation dependent glycoproteins on the surface of unfixed platelets after stimulation with adenosine diphosphate [ADP]. A total of 32 normal subjects were recruited in this study. CBC, Hb A1C, fasting and random blood sugar, urea, creatinine, cholesterol, triglycerides, high density as well as low density lipoproteins were determined. Flow cytometric analysis of platelets was done using FACSCalibur [BD Bioscience]. Two sets of CD markers i.e. platelets CD41and CD61 and CD63 and CD 62p were studied during resting state and after stimulation with ADP. Mean +/- SD values of CD41 and CD61 surface markers of resting and stimulated platelets showed no statistical difference; p value being 0.198 and 0.486 respectively. Comparison of CD41 and CD61 markers at 20 minutes Vs 2 hrs, 20 minutes Vs 3 hrs and 2 hrs Vs 3 hrs didn't show any significant difference after stimulation with ADP. This indicates that these markers remain stable and they are not affected by incubation for up to 3 hours. Activation of platelets with ADP resulted in an increase in the number of CD63 and CD62p positive platelets with a p value of 0.001. Activity of CD63 remained high while that of CD62p progressively decreased after incubation for 2 and 3 hours. CD63 is an ideal marker to evaluate functional status of the platelets while CD62p positivity, though it increases after activation, cannot be used alone as a marker of platelet activation because its positivity decreases with the passage of time. Changes in CD62p positivity when considered in conjunction with increased CD63 positivity lend support to the presence of increased number of activated platelets in the peripheral blood