THE BRAIN no longer corners the amyloid β-protein market. Sensitive assays have recently detected the notorious protein in several nonneural tissues of patients with Alzheimer's disease, including the skin, intestine, and adrenal gland. Researchers say the discovery has major implications for the pathogenesis and treatment of this disease.
The finding has come as a surprise to investigators, even to the researchers at Harvard Medical School, Boston, Mass, who conducted the experiments. "It has always been assumed, since Alzheimer described the disease in 1906, that it involved only the brain," says Dennis Selkoe, MD, codirector of Brigham and Women's Hospital's Center for Neurologic Diseases and professor of neurology and neuroscience at Harvard.
The subclinical deposition of small amounts of amyloid β-protein in nonneural tissues lends support to the hypothesis, yet to be proven, that this protein originates in the bloodstream, or is produced locally in a variety of organs.