Modification of platelet shape change parameter by oxidized lipoprotein from beta-thalassemia/Hemoglobin E.

BACKGROUND: Beta-thalassemia/Hemoglobin E (beta-thal/Hb E) is a congenital hemolytic anemia that is prevalent in Thailand Pulmonary arterial occlusion is the cause of morbidity and mortality in these patients. Abnormality of platelets has been implicated as pathogenesis of this condition. However the blood-borne factors that induce platelet activation are not identified Recently, oxidized low-density lipoproteins (ox-LDLs) had been identified in thalassemic blood. OBJECTIVE: Identify whether oxidized LDL is the blood bone factor that induce platelet activation in beta-thal/Hb E patients. MATERIAL AND METHOD: Platelet activation was measured by monitoring platelet shape change parameter using plasma-free human platelets. The shape change parameter was monitored following exposure to normal LDL, oxidized LDL, and thalassemic LDL. RESULTS: Oxidized LDL, but not the native LDL and thalassemic LDL, showed platelet activation activity. Oxidation of thalassemic LDL with copper give rise to oxidized LDL with platelet activating activity. However less copper was needed by LDL from splenectomized beta-thal/Hb E patients than those from nonsplencectomized beta-thal/Hb E patients. CONCLUSION: LDL from splenectomized beta-thal/Hb E patients is more susceptible for oxidation and gives rise to oxidized-LDL that plays an important role in thrombosis event in these patients.

Modification of platelet shape change parameter by modified phospholipids in oxidized LDL.

BACKGROUND: It is believed that the oxidatively modified lipoproteins play a critical role in activating platelets and is a contributing factor in the etiology of a number of cardiovascular-related diseases. OBJECTIVE: Identify the active component(s) of oxidized LDL that initiated shape change in plasma-free human platelets prepared by a gel filtration method Material and Method: Shape change parameter of platelets was monitored following exposure platelets to LDL, copper sulfate-oxidized LDL, and different types of lipids extracted of the corresponding LDL. RESULTS: Oxidized LDL, but not native LDL, increased the shape-change parameter in a concentration-dependent manner Specifically, phosphatidyl serine from oxidized LDL was responsible for this effect. CONCLUSION: Oxidized phospholipids generated during the oxidative modification of LDL are likely to be the active components responsible for changes in platelet function.

Pueraria mirifica, phytoestrogen-induced change in synaptophysin expression via estrogen receptor in rat hippocampal neuron.

OBJECTIVE: To examine Pueraria mirifica (Leguminosae) containing-phytoestrogen effect on synaptic density and involvement of estrogen receptor. MATERIAL AND METHOD: The level of synaptophysin, a presynaptic vesicle protein, was measured using Western blot analysis and immunocytochemistry in hippocampal primary cell cultures at 6 days in vitro. RESULTS: P. mirifica and 17beta-estradiol (0.1 microM) treatment for 4 days, but not for 2 days, significantly increased synaptophysin immunoreactivity and level of synaptophysin. P. mirifica up to 60 microg/ml resulted in a dose related increase in the level of synaptophysin immunoreactivity. The classical estrogen receptor antagonist, ICI 182 780, significantly blocked P. mirifica-induced increase in synaptophysin. CONCLUSION: P. mirifica-containing phytoestrogen affects synaptic density by inducing synaptophysin expression via estrogen receptor.