Oxidation has been proposed to be an important factor in the pathogenesis o
f Alzheimer's disease (AD) and amyloid beta is considered to induce oxidati
on. In biological fluids, including cerebrospinal fluid (CSF), amyloid beta
is found complexed to lipoproteins. On the basis of these observations, we
investigated the potential role of lipoprotein oxidation in the pathology
of AD. Lipoprotein oxidizability was measured in vitro in CSF and plasma fr
om 29 AD patients and found to be significantly increased in comparison to
29 nondemented controls. The levels of the hydrophilic antioxidant ascorbat
e were significantly lower in CSF and plasma from AD patients. In plasma, a
lpha-carotene was significantly lower in AD patients compared to controls w
hile alpha-tocopherol levels were indistinguishable between patients and co
ntrols. In CSF, a nonsignificant trend to lower alpha-tocopherol levels amo
ng AD patients was found. Polyunsaturated fatty acids, the lipid substrate
for oxidation, were significantly lower in the CSF of AD patients. Our find
ings suggest that (i) lipoprotein oxidation may be important in the develop
ment of AD and (ii) the in vitro measurement of lipid peroxidation in CSF m
ight become a useful additional marker for diagnosis of AD. (C) 2000 Elsevi
er Science Inc.