Increased proteolytic activity in lymphocytes from patients with early onset Alzheimerʹs disease

The levels of calpains (m-calpain and μ-calpain) in peripheral blood lymphocytes from patients with Alzheimerʹs disease were determined via Western blotting. The Ca-dependent proteolytic activity and the calpastatin activity were estimated using incubation with exogenous substrate. Evidence was obtained for an increased Ca-dependent proteolytic activity in lymphocytes from patients with early onset Alzheimerʹs disease. There was also an increased level of membrane-bound μ-calpain in this group of patients. The observed changes may be caused by a general dysregulation of Ca homeostasis in peripheral cells of early onset Alzheimer victims.