Cytosolic calcium alterations in platelets of patients with early stages of Alzheimer's disease.

ABSTRACT

Alterations in calcium homeostasis might be implicated in the neuropathology of Alzheimer's disease (AD). To date it is not clear whether changes in cytosolic calcium level ([Ca2+ ]i) are the result or the cause of pathogenic effects. In platelets of patients with early stages of AD, the basal values of [Ca2+]i in the absence of extracellular Ca2+ were significantly lower in comparison with age-matched and young controls. After the addition of 1 mM calcium into the incubation medium the [Ca2+]i markedly increased in platelets of AD patients whereas the increase only to a smaller extent was observed in control age-matched and young subjects. The present study proposes that calcium dysregulation during the whole disease period could not be uniform and according to our results the [Ca2+]i is reduced in the first stages of AD. We suggest that the disturbed calcium homeostasis in AD is an "early defect."