Heat-shock protein 70 levels in brain of patients with Down Syndrome and Alzheimer's disease

Heat-shock proteins are proteins serving as molecular chaperones, involved in the protection of cells from various forms of stress. Since the expressi on of these proteins is closely related to that of amyloid precursor protei n (APP), heat-shock protein has been studied in brain of patients with Alzh eimer's disease (AD) and furthermore, brain Hsp70 mRNA levels were related to the agonal state. The aim of our study was to demonstrate the presence o f Hsp70 - immunoreactive protein in brain of controls, patients with AD and Down Syndrome (DS) in individual brain regions. The rationale for the stud y was to test the hypothesis that expression of Hsp70, a protein involved i n apoptosis would be altered in brain of these patients with neurodegenerat ive disorders where (neuronal) apoptosis is a hallmark of the disease. Brai n immunoreactive-Hsp70 - protein (Hsp70) was determined by Western blotting using specific monoclonal antibody in five different brain regions (fronta l, parietal, occipital, temporal cortex and cerebellum) from controls, DS a nd AD patients. Hsp70 expression was significantly increased in temporal co rtex of patients with AD (arbitrary units: means +/- SD; 0.35 +/- 0.49 for controls, 0.97 +/- 0.70 for DS patients, 1.16 +/- 0.56 for AD patients). In frontal and parietal cortex from DS patients, there was a strong correlati on between Hsp70 levels and the length of post-mortem interval (r = 0.95, P < 0.01 and r = 0.82, P < 0.021).