Scientists at UMass Lowell have identified a new mechanism by which a key protein linked to Alzheimer's disease can spread within the human brain. According to the researchers, the finding gives new hope that the disease may someday be cured.

It provides a new explanation of how the protein tau, a normal human protein that becomes toxic in Alzheimer's patients, can appear in their cerebrospinal fluid (CSF).

"My team has discovered two different ways in which tau is secreted by neurons, or brain cells. This might explain how tau-containing lesions seem to propagate between adjacent, interconnected parts of the brain during the development of the disease," UMass Lowell biological sciences professor and study's lead author Garth Hall said.

Until very recently, it was universally assumed by scientists that tau is never secreted from or transferred between neurons, and that CSF-tau only appears after many neurons have died and irreversible harm has been done to the brain.

"That tau secretion can occur via two distinct mechanisms strongly indicates that it is biologically 'real' and is not just tau protein leaking out of dead neurons," said Hall.

"The fact that it occurs in a pattern that reproduces what is seen in the CSF of Alzheimer's patients holds out hope that patients in early stages of the disease might someday be cured.

"If we can distinguish secreted tau from tau that is released from dying neurons in CSF samples, then maybe we can diagnose Alzheimer's in time to stop the disease before the neurons die," Hall added.