Alzheimer's disease (AD) and vascular dementia (VD) are the two most c
ommon causes of dementia. As yet, no definitive biological antemortem
marker has been established for differential diagnosis of AD or VD. In
this study, proteins of cerebrospinal fluid (CSF) from AD, VD and con
trol patients were analyzed by two-dimensional (2-D) electrophoresis w
ith immobilized pH gradients in the first dimension. No specific chang
es for AD or VD could be detected in the 2-D CSF patterns. However, a
spot of haptoglobin alpha-1 chains (13.5 kDa; approximate pI 4.6) was
found to be present in the majority of 2-D CSF maps from the dementia
cases, suggesting a high-molecular-weight transudate type of alteratio
n in the blood-brain barrier with considerable frequency in AD.