FREE D-AMINO ACIDS IN HUMAN CEREBROSPINAL-FLUID OF ALZHEIMER-DISEASE,MULTIPLE-SCLEROSIS, AND HEALTHY CONTROL SUBJECTS

This is the first report of the presence of free D-amino acids in lumb ar and ventricular human cerebrospinal fluid (CSF) of individuals with Alzheimer disease (AD) compared with CSF of normal control subjects a nd with individuals affected by multiple sclerosis, as an unrelated ne urologic disorder. Free D-amino acids are present at significantly hig her levels in AD CSF than normal CSF, whereas in the CSF of patients a ffected by multiple sclerosis, D-amino acids occurs at the same level as in the normal controls. The total D-amino acid content in ventricul ar CSF was 1.48 times higher in the AD than controls (26.4 vs 17.9 nmo l/ml, p = 0.025). The total D-amino acid content was 1.43 times higher in AD lumbar CSF than controls (1.89 vs 1.32 nmol/mL, p = 0.001). D-A spartate in particular was 2.74 times higher in AD ventricular CSF com pared to normal ventricular CSF (3.34 vs 1.22 nmol/mL, p = 0.029). In lumbar CSF, D-aspartate was 1.5 times higher in AD than controls (0.05 4 vs 0.036 nmol/mL, p = 0.041). Previously we reported that D-amino ac ids are elevated in AD brain proteins associated with neurofibrillary tangles compared to normal brain proteins (D'Aniello et al., 1992c; Fi sher et al., 1992a,b). Thus, the D-amino acids present in CSF may orig inate from degradation of brain proteins.