Melatonin Shows Promise for Application in Alzheimer's Treatment

INDIANAPOLIS--Melatonin may have the potential to treat Alzheimer's disease (AD) because of its capacity to reduce the development of a protein complex that is a hallmark of the disease. The results of this in vitro study were published in the American Chemical Society's Biochemistry (40,49: 14995-5001, 2001) (http://pubs.acs.org/journals/bichaw).

Researchers from the Indiana University School of Medicine added melatonin to animal and human cell cultures that contained the building blocks of abnormal brain amyloid fibrils as well as human apoE4--a protein associated with strong risk for developing AD. "Inheritance of apoE4 is a strong risk factor for the development of late-onset sporadic AD," the researchers wrote. "Several lines of evidence suggest that apoE4 promotes formation of beta-sheet structures and amyloid fibrils. Deposition of amyloid fibrils is a critical step in the development of AD."

Researchers reported that the addition of melatonin to brain cells in the presence of apoE inhibited fibril formation more effectively than with melatonin alone. This result was, however, structure-dependent upon melatonin, but not related to melatonin's antioxidant properties.

"Our results clearly demonstrate the ability of melatonin to inhibit the process of forming the 'signature' amyloid protein bundles seen in Alzheimer's disease," said Miguel Pappolla, M.D., study researcher. "This activity attributed to the 'indole' structure of melatonin appears to be specific. These exciting findings, however, mandate much more research before we can convincingly state melatonin can halt or prevent Alzheimer's disease."

This study was supported by a grant from the National Institute on Aging (www.nia.nih.gov).