Importance of platelet functions in Alzheimer's disease

The function of platelets of patients with Alzheimer's disease has been characterized. The shape of platelets is more spherical and the initial rate of platelet aggregation caused by different agonists measured in plasma is faster in the case of Alzheimer's disease and senile dementia of the Alzheimer-type than that of other demented patients: multi infarct dementia and probable vascular dementia. Although fast aggregation is characteristic of activated platelets but the Alzheimer platelets are not hypersensitive. The activation of Alzheimer platelets makes the velocity of ADP induced aggregation slower and it is different than the behaviour of normal activated platelets. The shape-associated parameter and the initial rate of 50 microM ADP-induced aggregation of platelets non-activated and activated by cytochrome C are recommended for establishing the diagnosis of Alzheimer's disease and senile dementia of the Alzheimer-type. The evaluation of these parameters has been discussed. The cytochrome C may be useful to normalize the function of Alzheimer platelets in plasma, not only in vitro.