Discovery of specific protein may lead to future Alzheimer's treatment

• The protein, P-glycoprotein (Pgp), has long been known to obstruct chemotherapy drugs and other drugs used in treating brain disorders.
• But, by creating drugs that alter the natural levels of Pgp, it may be possible to prevent and treat Alzheimer's disease, the researchers suggest.
• "We found a new way of getting amyloid out of the brain," said lead author John Cirrito, a postdoctorate research fellow at Washington University School of Medicine in St. Louis.
• "Now there are avenues we can explore to try to find a treatment.
• Pgp is one of several molecular transporters that form the blood-brain barrier, a layer of cells that limits the ability of many types of molecules -- including many drugs -- to enter the brain through the circulatory system, Cirrito said.
• "In the blood-brain barrier, it normally acts to keep molecules out of the brain," he explained, adding the protein actually pumps molecules out of brain cells.
• Earlier research had hinted that Pgp could also transport amyloid beta molecules out of the brain, Cirrito said.
• "We basically show that if we inject amyloid beta into the brains of mice, Pgp can pump amyloid beta out of the brain," he said.
• The researchers also found that when specially bred mice were given a Pgp inhibitor, amyloid beta levels significantly increased in just a few hours.
• Cirrito believes these findings might be used one day to both treat and prevent Alzheimer's disease.
• "If you could enhance Pgp activity, perhaps you could get amyloid beta out of the brain and not let it build up," he said.
• "There are drugs that are used to inhibit Pgp in cancer therapy to help chemotherapy drugs get into tumor cells," Cirrito said.