Serum heart-type fatty acid-binding protein and cerebrospinal fluid tau: Marker candidates for dementia with Lewy bodies

Background: The measurement of biomarkers in cerebrospinal fluid
(CSF) has gained increasing acceptance in establishing the
diagnosis of some neurodegenerative diseases. Heart-type fatty
acid-binding protein (H-FABP) was recently discovered in CSF and
serum of patients with neurodegenerative diseases. Objective: We
investigated H-FABP in CSF and serum alone and in combination with
CSF tau protein to evaluate these as potential biomarkers for the
differentiation between dementia with Lewy bodies (DLB) and
Alzheimer's disease (AD). Methods: We established H-FABP and tau
protein values in a set of 144 persons with DLB (n = 33), Parkinson
disease with dementia (PDD; n = 25), AD (n = 35) and nonclemented
neurological controls (NNC; n = 51). Additionally, serum H-FABP
levels were analyzed in idiopathic Parkinson disease patients
without evidence of cognitive decline (n = 45) using commercially
available enzyme-linked immunosorbent assays. We calculated
absolute values of HFABP and tau protein in CSF and serum and
established relative ratios between the two to obtain the best
possible match for the clinical working diagnosis. Results: Serum
HFABP levels were elevated in DLB and PDD patients compared with
NNC and AD subjects. To better discriminate between DLB and AD, we
calculated the ratio of serum H-FABP to CSF tau protein levels. At
the arbitrary chosen cutoff ratio >= 8 this quotient reached a
sensitivity of 91% and a specificity of 66%. Conclusion: Our
results suggest that the measurement of CSF tau protein, together
with H-FABP quantification in serum and CSF, and the ratio of serum
H-FABP to CSF tau protein represent marker candidates for the
differentiation between AD and DLB. Copyright (c) 2007 S. Karger
AG, Basel.