Activity of platelet in patients with high level of LDL and the effect of LDL on platelet glycoproteins.

OBJECTIVE: To investigate the activity of platelet in patients with high level of low density lipoproteins (LDL) and the effect of LDL on platelet glycoproteins (GP). METHODS: Platelet glycoproteins, whose platelet were activated or unactivated, were measured by flow cytometry. RESULTS: The amount of the platelet membrane GP II b/III a in patients was not significantly different from that of the control when platelet was unactivated (P > 0.05); when platelet was activated by adenosine diphosphate (ADP), the amount of patients' platelet GP II b/III a was increased markedly in comparison with that in the control (P < 0.01). Having been preincubated with LDL, the platelets were activated by ADP and the amounts of GP II b/III a of patients group and the control were all increased obviously as compared with those in the platelets which were not incubated with LDL (P < 0.01; P < 0.01). There was no significant difference of the amount of granule membrane protein-140 (GMP-140) between patients and the control when platelet was activated by thrombin (P > 0.05). Having been preincubated with LDL, platelet was activated by thrombin, the amounts of GMP-140 on patients' and control platelet were all increased markedly (P < 0.01, P < 0.01). CONCLUSION: The activity of platelet in patients with high level of LDL is increased significantly. LDL can increase the expression of platelet glycoproteins.