Homocysteine and methylmalonic acid concentrations in cerebrospinal fluid: relation with age and Alzheimer's disease.
BACKGROUND
Homocysteine may be involved in the pathogenesis of late onset Alzheimer's disease. It is implicated in the metabolism of several important pathways in the brain. Methylmalonic acid (MMA) is related to the metabolism of branched chained amino acids and fatty acids.


OBJECTIVE
To compare cerebrospinal fluid (CSF) total homocysteine and MMA in elderly subjects, patients with Alzheimer's disease, and younger healthy controls.


METHODS
CSF samples were obtained from 33 patients under 20 years of age; 28 patients aged 21 to 60 years; 22 normal elderly subjects aged over 60; and 38 Alzheimer patients aged over 60.


RESULTS
CSF total homocysteine increased with age (mean (SD): 57 (35) nmol/l in the youngest group v 123 (89) nmol/l in the elderly group (p<0.001)). There was no difference between the elderly group and Alzheimer patients (115 (62) nmol/l). CSF MMA did not differ in the elderly group and the Alzheimer group (38 (13) v 35 (14) ng/ml). In the youngest group, it was significantly higher (60 (15) ng/ml).


CONCLUSIONS
CSF total homocysteine is not increased in Alzheimer's disease compared with age matched controls. CSF total homocysteine was correlated with age. The decrease in CSF MMA levels with age eliminates a lack of vitamin B-12 at neuronal level.
Serot
J-M
JM
Department of Geriatric Medicine, Hôpital Sud, Amiens, France. serot.jean-marie@chu-amiens.fr
Barbé
F
F
Arning
E
E
Bottiglieri
T
T
Franck
P
P
Montagne
P
P
Nicolas
J-P
JP
D000328:Adult; D000368:Aged; D000544:Alzheimer Disease / Q000134:cerebrospinal fluid* / Q000503:physiopathology*; D005260:Female; D006710:Homocysteine / Q000134:cerebrospinal fluid*; D006801:Humans; D008297:Male; D008764:Methylmalonic Acid / Q000134:cerebrospinal fluid*; D008875:Middle Aged
D006710:Homocysteine; D008764:Methylmalonic Acid