"Our results show several new findings. We now know that P-glycoprotein plays a pivotal role in clearing beta-amyloid from the brain. Secondly, we know P-glycoprotein levels are reduced in the blood-brain barrier, and that the Alzheimer's mice treated with the chemical to activate PXR were able to reduce their beta-amyloid levels to that of mice without Alzheimer's," said Bjorn Bauer, Ph.D., assistant professor at the University of Minnesota and senior author on the paper.

Anika Hartz, Ph.D., lead author on the study, added that it is also likely that reduced P-glycoprotein expression at the blood-brain barrier may be an early indicator of Alzheimer's disease, even before the cognitive symptoms appear. One of the challenges confronting the diagnosis and treatment of Alzheimer's is being able to clearly diagnose the disease process when brain damage is minimal, before any symptoms occur.

"More research is needed before this animal model discovery can be tested in humans, but the paper suggests some new targets for treatment that offer hope to patients and families dealing with this devastating disease," said NIEHS Director Linda Birnbaum, Ph.D.

The researchers plan to conduct a study where the Alzheimer's mice are fed a PXR-activating compound in their diet for 12-18 months. The cognitive skills of the animals will be monitored regularly, along with their P-glycoprotein levels, to determine whether the feeding regimen delays the onset of cognitive impairment.

Source: NIH/National Institute of Environmental Health Sciences