Plasma prion protein concentration and progression of Alzheimer disease

Background/Objective: Recently, PrPc has been linked to AD pathogenesis. Second, a relation of PrPc plasma levels with cognitive status and decline of healthy elderly subjects has been reported. Therefore, we hypothesized baseline plasma levels of PrPc to be associated with AD progression in cognitive and functional domains. Methods: AD patients (n = 84) were included into an observational study at time of diagnosis. Baseline plasma PrPc levels were determined. Decline was assessed annually (mean follow-up time 3 years) with the aid of different standardized tests (MMSE, iADL, bADL, GDS, UPDRSIII). Multiple regression analyses were used to uncover potential associations between decline and PrPc levels. Results: No association of PrPc and decline could be established. Presence of diabetes mellitus was linked to slower deterioration. Intake of neuroleptic drugs or memantine was associated with faster progression. Conclusion: Plasma PrPc at baseline could not be shown to be related to AD progression in this study. An interesting association of diabetes mellitus and decline warrants further investigation.