Vaccines May Work Best in Early Stage Alzheimer's Patients
November 16, 2011 – Patients just starting to experience the effects of Alzheimer’s disease will likely benefit most from vaccine therapies now being tested in human clinical trials, say researchers from Georgetown University Medical Center (GUMC).
Active immunization involves injecting amyloid protein in patients so they can mount an antibody response (similar to getting a flu shot). Amyloid is the protein that builds up in the brains of Alzheimer’s patients and is thought to be the primary cause of the disease.
The researchers, who recently presented the study at the annual meeting of the Society for Neuroscience, are the first to show that mice with a large brain burden of amyloid protein were much more likely to experience significant brain inflammation.
Such inflammation interferes with the effectiveness of the vaccine, while mice with less amyloid protein in their brains showed a significant benefit from the immunization.
While patients often don’t know they have brain inflammation and have no symptoms, the swelling appears on MRI scans routinely performed on patients enrolled in clinical trials, says Dr. R. Scott Turner, the study’s lead investigator.
“Excessive inflammation … is counter-productive because it will limit the benefits of the vaccine treatment,” he says, “and in a few cases, will cause new problems.”
Turner is director of the Georgetown University Memory Disorders Program and a lead investigator of new therapies for neurological disorders, including vaccines.
Based on the study, he says vaccines now being tested in patients with Alzheimer’s may work better in patients with mild cognitive impairment, a precursor of Alzheimer’s.
GUMC is now recruiting volunteers for a new clinical trial testing a vaccine in mildly cognitive-impaired patients with low levels of amyloid protein.
“We may find that in the future, we will have to tailor immunization therapies based on amyloid burden in individual patients,” Turner says.
Researchers at the National Institutes of Health and Case Western Reserve University participated in the study, which was funded by the National Institutes of Health.