In Butterfield's study, which was funded by the National Institutes of Health, he focused on amyloid beta peptide, a compound known to contribute to the senile plaques seen in the brains of Alzheimer's patients. The study compared amyloid beta peptide in an animal model to the same compound in humans and found both forms of the compound cause loss of connections between neurons and decreased cell viability as well as other damage associated with Alzheimer's.
Butterfield's study identified methionine in the human amyloid beta peptide as a key contributor to Alzheimer's disease. A previous theory held that it was the copper binding sites in the human peptide that contributed to Alzheimer's. His study found the animal form of the peptide, which does not have the copper binding sites, still causes damage. Butterfield says this indicates the damage to neurons caused by the human peptide in an Alzheimer's disease patient is related to the peptide's methionine residue.
Butterfield also demonstrated that in the animal form of the peptide, the introduction of the antioxidant vitamin E slowed the destruction of brain cells as it appears to in the human form. These results provide new insights into the mechanisms of action of human amyloid beta peptide, which many researchers believe causes the damage seen in the brains of Alzheimer's disease patients.
Butterfield's complete paper is in the October issue of the Journal of Alzheimer's Disease.