Differences in red blood cell choline and lipid-bound choline between patients with Alzheimer disease and control subjects.

The concentrations of red blood cell choline, glycerophosphocholine, phosphocholine and lipid-bound choline were measured in patients with Alzheimer disease (AD) and in normal elderly controls. Red blood cell choline in the Alzheimer group (41.4 +/- 9.2 nmol/ml) was significantly higher (p less than 0.023) than in the elderly controls (18.7 +/- 2.3 nmol/ml). Red blood cell lipid-bound choline (1387 +/- 58 nmol/ml) in the AD group was significantly lower (p less than 0.0022) than in the age-matched controls (1667 +/- 65), while there were no significant differences in glycerophosphocholine or phosphocholine. Plasma choline and lipid-bound choline did not differ significantly between the groups. The mechanisms for these changes still need further study, although the finding of decreased lipid-bound choline supports the concept of altered phospholipid metabolism in patients with AD.