Glycolytic and Proteolytic Metabolism in Erythrocytes from Elderly and Demented Patients

Background: Accumulating evidence implicates a role for altered energy and proteolytic metabolism in the pathogenesis of Alzheimer disease (AD), but the involvement of erythrocytes (RBC) remains to be completely understood. The objective stands to test a hypotheses that erythrocytic glycolytic and proteolytic metabolism is disturbed in the elderly and in AD patients. Methods: This pilot study analyzed the levels of the key glycolytic and proteolytic enzymes and metabolites in RBC from patients with AD and non-Alzheimer’s dementia (NA), from age-matched (AC) and young adult (YC) controls. Results: Glycolytic enzymes displayed lower activities in AC, and similar or higher activities in AD and NA, as compared to those in YC. Caspase-3 and calpain activities in AC were about 3 times those of YC. There were no differences between AC, AD and NA in proteolytic enzymes. Conclusion: Among glycolytic parameters studied in four subject groups, only hexokinase activity specifically increases in AD. Changes in other glycolytic and proteolytic enzyme activities and metabolite concentrations in RBC were not specific to dementias but characteristics for aging.