CSF prion protein concentration and cognition in patients with Alzheimer disease

Background/Objective: PrPc has been suggested to play a role in AD pathophysiology. CSF concentrations of PrPc have been shown to be reduced in AD compared with healthy controls. Furthermore, serum levels of PrPc have recently been reported to be associated with the cognitive status of healthy elderly subjects. Therefore, we hypothesized that CSF levels of PrPc could be associated with cognitive function of AD patients at the time of diagnosis. Results: No association of CSF PrPc and cognitive status could be established, while other factors (i.e., use of antipsychotic drugs, use of anti-dementia drugs, female sex, pre-progression time) were related to worse cognitive function in some domains. Methods: AD patients (n = 114) included into an observational study underwent CERAD testing and lumbar puncture at time of diagnosis / study inclusion. CSF PrPc was determined. Generalized linear models were fitted to assess the associations of PrPc plus a variety of possible confounding factors and CERAD subscale measures. Conclusion: CSF PrPc appears not to be a useful biochemical surrogate of cognitive status in AD at the time of diagnosis. Follow-up analyses will examine possible associations with the speed of cognitive decline.