Effect of Clopidogrel on Platelet Membrane CD40 Ligand in Coronary Artery Disease Patients Undertaking Percutaneous Coronary Intervention

Objectives To investigate the change and clinical significance of clopidogrel on platelet membrane CD40L in coronary artery disease patients before and after percutaneous coronary intervention(PCI). Methods 30 cases who were diagnosis coronary artery diseases(CAD) by coronary angiography, mean age 56±9 years old. All the patients who had no antiplatelet aggregation contraindication, were treated with standard anti angina pectoris drugs. Before PCI, all the patients took clopidogrel 75 mg per day. Activated platelet membrane CD40L express rate was measured by flow cytometry before and after PCI 6 hours. Results Activated platelet membrane CD40L express rate were 3.73±2.15 and 2.46±0.90, respectively in 30 patients before and after PCI 6 hours. Activated platelet membrane CD40L express rate was significantly decrease after PCI 6 hours than that before PCI(P<0.01). Conclusions Clopidogrel has significance effect on platelet membrane CD40L in coronary artery disease patients undergoing PCI. Clopidogrel can suppression platelet activation and prevent thromboembolism event occurrence.

Role of platelet TLR4 expression in pathogensis of septic thrombocytopenia

BACKGROUND： Infection-induced thrombocytopenia （TCP） is an independent risk factor for death of patients with sepsis, but its mechanism is unknown. This study aimed to explore the underlying mechanism of TCP based on the relationship between TLR4 expression and platelet activation in septic patients. METHODS： A total of 64 patients with sepsis were prospectively studied. Platelet count （PC）, mean platelet volume （MPV）, platelet distribution width （PDW）, platelet TLR4 expression, platelet PAC-1 expression, sCD40L and TNF-a concentrations were compared between the healthy control group （15 volunteers） and sepsis group （64 patients） at admission and on the 3, 5, and 9 days after admission. The changes of MPV and PDW in the TCP and non-TCP subgroups of sepsis before and after treatment were recorded. Prognostic index was analyzed. RESULTS：PC was lower in the sepsis group （P=0.006）, and MPV and PDW were higher in the sepsis group than those in the healthy control group （P=0.046, P=0.001）. Platelet TLR4 and PAC-1 expressions, and sCD40L and TNF-a levels increased more significantly in the sepsis group （P〈0.001）. PAC-1 expression and TNF-a level were higher in the TCP group than in the non-TCP group before and after treatment （P=0.023, P=0.011）. sCD40L concentration and platelet TLR4 expression were significantly higher in the treated TCP group than in the non-TCP group （P=0.047, P=0.001）. Compared to the non-TCP group, the rate of bleeding was higher （P=0.024） and the length of ICU stay was longer （P=0.013）. The APACHE II score and the 28-day mortality were higher in the TCP group （P〈0.01, P=0.048）. CONCLUSIONS：The elevation of platelet TLR4 expression in sepsis along with platelet activation is closely related to the incidence of thrombocytopenia. The occurrence of TCP is a sign of poor prognosis in sepsis patients.

Platelets in Kawasaki disease:Is this only a numbers game or something beyond?

Kawasaki disease(KD)is a medium vessel vasculitis with predilection to cause coronary artery abnormalities.KD is now the most common cause of acquired heart disease in developed countries.Thrombocytosis is consistently found in patients with KD,usually in 2nd to 3rd week of illness.Thrombocytopenia has occasionally been reported in the acute phase of KD.An increase or decrease in platelet number in patients with KD was initially considered to be a benign phenomenon.However,recent literature on platelet biology in KD has suggested that platelets are not only increasing but are rather activated.This phenomenon has been found to increase the risk of thrombosis in these patients.Similarly a fall in platelet counts during acute stage of KD has also been found to be associated with increased severity of disease.In this review,we update on the current best understanding about pathogenic role of platelets in patients with KD.