Are Brains with Alzheimer Disease All Gummed Up?

Chronic periodontal disease in humans has been associated with more pronounced progression of Alzheimer disease (AD), and the key pathogen in periodontal disease, Porphyromonas gingivalis, a gram-negative bacterium, and toxic proteases (gingipains) produced by these bacteria have been identified in brains of AD patients. In a manufacturer-funded study, investigators (many employed by the manufacturer) studied human brain-bank samples and mouse models to ascertain whether these gingipains are neurotoxic and potential therapeutic targets.

In postmortem studies, brains of patients with AD showed greater gingipain loads than brains from nondemented controls. In control brains, gingipain load correlated with the extent of tau pathology, suggestiv…