Plasma prion protein concentration and progression of Alzheimer disease.

Background/objective: Recently, PrP(c) has been linked to AD pathogenesis. Second, a relation of PrP(c) plasma levels with cognitive status and decline of healthy elderly subjects has been reported. Therefore, we hypothesized baseline plasma levels of PrP(c) to be associated with AD progression in cognitive and functional domains.

Materials And Methods: AD patients (n = 84) were included into an observational study at time of diagnosis. Baseline plasma PrP(c) 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 PrP(c) levels.

Results: No association of PrP(c) 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 PrP(c) 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.