Homocysteine, vitamin B6, and vascular disease in AD patients.
BACKGROUND
Cerebrovascular disease is a cause of dementia and is associated with elevated plasma levels of homocysteine. Patients with AD tend to have unexplained elevations of homocysteine concentrations vs healthy control subjects. Vitamin B(6) status, a potential determinant of plasma homocysteine, has not been characterized in patients with AD.


OBJECTIVE
To investigate plasma homocysteine, vitamin B(6) status, and the occurrence of vascular disease in patients with AD.


METHODS
Forty-three patients with AD and 37 control subjects without AD were studied for homocysteine, B vitamin status (folate, vitamin B(12), pyridoxal-5'-phosphate [PLP]), kidney function (creatinine), and thyroid function (thyroid-stimulating hormone, thyroxin). In addition, the presence of vascular disease was assessed by reviewing both medical histories and brain imaging data provided by CT and MRI.


RESULTS
The OR for elevated plasma homocysteine (>12 micromol/L) was only 2.2 (not significant) for subjects with AD. In contrast, the OR was 10.0 (p = 0.03) for subjects with vascular disease (n = 26). The OR for low plasma PLP (<25 nmol/L) was 12.3 (p = 0.01) for patients with AD. No significant relationship was observed between vascular disease and PLP level or between plasma homocysteine and PLP concentrations.


CONCLUSIONS
Elevated plasma homocysteine in patients with AD appears related to vascular disease and not AD pathology. In addition, low vitamin B(6) status is prevalent in patients with AD. It remains to be determined if elevated plasma homocysteine or low vitamin B(6) status directly influences AD pathogenesis or progression.
Miller
J W
JW
Department of Medical Pathology, University of California, Davis, School of Medicine, Sacramento 95817, USA. jwmiller@ucdavis.edu
Green
R
R
Mungas
D M
DM
Reed
B R
BR
Jagust
W J
WJ
D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000097:blood*; D000787:Angina Pectoris / Q000097:blood; D020520:Brain Infarction / Q000097:blood; D003327:Coronary Disease / Q000097:blood; D005260:Female; D006333:Heart Failure / Q000097:blood; D006710:Homocysteine / Q000097:blood*; D006801:Humans; D002546:Ischemic Attack, Transient / Q000097:blood; D008297:Male; D009203:Myocardial Infarction / Q000097:blood; D016017:Odds Ratio; D011732:Pyridoxal Phosphate / Q000097:blood; D020521:Stroke / Q000097:blood; D014652:Vascular Diseases / Q000097:blood*; D025101:Vitamin B 6 / Q000097:blood*
D006710:Homocysteine; D011732:Pyridoxal Phosphate; D025101:Vitamin B 6