Irizarry_2007_Neurodegener.Dis_4_403

BACKGROUND: Oxidative damage is implicated in the pathophysiology of Alzheimer's disease (AD). F2-isoprostane is a marker of lipid peroxidation which is elevated in AD CSF. Plasma F2-isoprostane has been proposed as a diagnostic marker for AD and mild cognitive impairment (MCI). OBJECTIVE: To determine whether plasma F2-isoprostane levels differ between nondemented control individuals and patients with AD, MCI, or Parkinson's disease (PD).
METHODS: We collected plasma from191 outpatients with a diagnosis of AD (49), MCI (47), nondemented PD (47), and no dementia (48). Plasma levels of the isoprostane iP2alpha-IV (F2A) were determined by gas chromatography/mass spectroscopy.
RESULTS: Mean plasma levels of F2A isoprostane did not differ significantly between the four diagnostic groups. Within the MCI and AD groups, F2A levels did not correlate with duration of memory impairment or with cognitive test scores. F2A levels were marginally lower in users of cholinesterase inhibitors and individuals with an APOE epsilon4 allele.
CONCLUSIONS: While CSF isoprostane levels are elevated in AD, plasma isoprostane measures were neither sensitive nor specific for the clinical diagnosis of MCI or AD.