Blood–Brain Barrier Integrity in Alzheimer's Disease Patients and Elderly Control Subjects

A defective blood–brain barrier (BBB) has been postulated to be present in Alzheimer's disease (AD), which would allow circulating β-amyloid peptide to enter the brain. The authors tested this hypothesis by studying BBB function in 14 individuals with probable AD and 9 elderly control subjects. A computed tomographic method was used to measure blood-to-brain transport (K₁), tissue-to-blood efflux (k₂), tissue plasma space (V_p), and tissue extracellular space (V_e) of meglumine iothalamate. Repeated-measures analysis of variance indicated no significant differences between the groups for any of the measures. The authors conclude that there is no generalized abnormality of the blood–brain barrier in AD.