Age-related changes in the blood-brain barrier.

Aging of the cerebral microcirculation results in significant alteration in the blood-brain barrier (BBB). The barrier function appears to remain intact in older animals, although it may be more susceptible to disruption by external factors (hypertension) and drugs (haloperidol). While overall transport processes do not change with age, aging animals and humans have altered BBB function of select carrier mediated transport systems including the transport of choline, glucose, butyrate and triiodothyronine. These age-related changes are the result of either alteration in the carrier molecules or the physiochemical properties of the cerebral microvessels. At the present time, it is not known whether changes in the BBB contribute to the age-related neurodegenerative diseases or are merely epiphenomena of aging.