title: Serum amyloid p component as a biomarker in mild cognitive impairment and Alzheimer's disease.
abstract: BACKGROUND
  Serum amyloid P component (SAP), present in amyloid-beta (Abeta) plaques in Alzheimer's disease (AD), may protect Abeta deposits against proteolysis, thereby promoting plaque formation. The aim was to investigate if SAP levels in cerebrospinal fluid (CSF) and serum can be used to discriminate controls, AD and mild cognitive impairment (MCI) patients, and to identify incipient AD among MCI patients.
  
  
  METHODS
  SAP levels in CSF and serum were determined in 30 controls, 67 MCI and 144 AD patients. At follow-up, 39 MCI patients had progressed to dementia, while 25 had remained stable (mean follow-up time: 2.6 +/- 1.0 and 2.1 +/- 0.8 years).
  
  
  RESULTS
  Cross-sectionally no differences were found in SAP levels in CSF and serum between the groups. MCI patients that had progressed to dementia at follow-up had lower CSF SAP levels (13 microgram/l, range 3.3-199.3 microgram/l) than MCI nonprogressors (20.2 microgram/l, range 7.0-127.7 microgram/l; p < 0.05) [corrected]. A low CSF SAP level was associated with a 2-fold increased risk of progression to AD (hazard ratio = 2.2; 95% confidence interval = 0.9-5.4).
  
  
  CONCLUSIONS
  Our data suggest that measurement of CSF SAP levels can aid in the identification of incipient AD among MCI patients.
authors.affiliation: Department of Neurology, Alzheimer Center, VU University Medical Center, Amsterdam, The Netherlands. n.verwey@vumc.nl
authors.forename: Nicolaas A
authors.initials: NA
authors.lastname: Verwey
authors.forename: Alie
authors.initials: A
authors.lastname: Schuitemaker
authors.forename: Wiesje M
authors.initials: WM
authors.lastname: van der Flier
authors.forename: Sandra D
authors.initials: SD
authors.lastname: Mulder
authors.forename: Cees
authors.initials: C
authors.lastname: Mulder
authors.forename: C Erik
authors.initials: CE
authors.lastname: Hack
authors.forename: Philip
authors.initials: P
authors.lastname: Scheltens
authors.forename: Marinus A
authors.initials: MA
authors.lastname: Blankenstein
authors.forename: Robert
authors.initials: R
authors.lastname: Veerhuis
mesh_terms: D000368:Aged; D000544:Alzheimer Disease / Q000097:blood* / Q000134:cerebrospinal fluid; D016229:Amyloid beta-Peptides / Q000097:blood / Q000134:cerebrospinal fluid; D015415:Biomarkers; D003072:Cognition Disorders / Q000097:blood* / Q000134:cerebrospinal fluid; D003430:Cross-Sectional Studies; D003937:Diagnosis, Differential; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D010446:Peptide Fragments / Q000097:blood / Q000134:cerebrospinal fluid; D012307:Risk Factors; D000683:Serum Amyloid P-Component / Q000134:cerebrospinal fluid / Q000378:metabolism*
chemical_list: D016229:Amyloid beta-Peptides; D015415:Biomarkers; D010446:Peptide Fragments; D000683:Serum Amyloid P-Component; C075222:amyloid beta-protein (1-42)