title: Longitudinal study of CSF biomarkers in patients with Alzheimer's disease.
abstract: BACKGROUND
  The CSF biomarkers tau and Abeta42 can identify patients with AD, even during the preclinical stages. However, previous studies on longitudinal changes of tau and Abeta42 in individual patients with AD and elderly controls report somewhat inconsistent results.
  
  
  RESULTS
  We investigated the levels of tau and Abeta42 at baseline and after 1 year in 100 patients with AD. In a second cohort of 45 AD patients we measured the CSF biomarkers at baseline and after 2 years. Moreover, in 34 healthy elderly controls the CSF biomarkers were followed for 4 years. The baseline levels of tau were increased with >60% in AD patients compared to controls (p<0.001), while baseline Abeta42 levels were decreased with >50% (p<0.001). In the AD group followed for 2 years, tau increased with 16% compared to the baseline levels (p<0.05). However, the levels of tau were stable over 4 years in the controls. The levels of Abeta42 did not change significantly over time in any of the groups. In the patients with AD, tau was moderately associated with worse cognitive performance already at baseline (p<0.05).
  
  
  CONCLUSIONS
  Tau and Abeta42 in CSF seem to reflect the underlying disease state in both early and late stages of AD. The slight increase in tau over time observed in the patients with AD is modest when compared to the relatively large difference in absolute tau levels between AD patients and controls. Therefore, these markers maintain their usefulness as state markers over time and might serve as surrogate markers for treatment efficacy in clinical trials.
authors.affiliation: Clinical Memory Research Unit, Department of Clinical Sciences Malmö, Lund University, Lund, Sweden.
authors.forename: Peder
authors.initials: P
authors.lastname: Buchhave
authors.forename: Kaj
authors.initials: K
authors.lastname: Blennow
authors.forename: Henrik
authors.initials: H
authors.lastname: Zetterberg
authors.forename: Erik
authors.initials: E
authors.lastname: Stomrud
authors.forename: Elisabet
authors.initials: E
authors.lastname: Londos
authors.forename: Niels
authors.initials: N
authors.lastname: Andreasen
authors.forename: Lennart
authors.initials: L
authors.lastname: Minthon
authors.forename: Oskar
authors.initials: O
authors.lastname: Hansson
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000134:cerebrospinal fluid*; D016229:Amyloid beta-Peptides / Q000134:cerebrospinal fluid; D015415:Biomarkers / Q000134:cerebrospinal fluid*; D016022:Case-Control Studies; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D016875:tau Proteins / Q000134:cerebrospinal fluid
chemical_list: D016229:Amyloid beta-Peptides; D015415:Biomarkers; D016875:tau Proteins