As they report in the international open-access medical journal PLoS Medicine, they have engineered mice to continuously produce Abeta in their brains. The production can be switched off by giving the mice the antibiotic tetracycline in their drinking water. This switch-off at a certain point is similar to what would happen to human patients who would receive enzyme inhibitors once diagnosed with AD. Without tetracycline, the brains of the mice at six months of age are loaded with amyloid plaques. When the researchers switched the system off after some initial plaques had formed, they found two things: the existing plaques didn't grow or spread to other areas of the brain, but they did not go away either.
As always, results from animal models cannot simply be extrapolated to human disease. However, this study suggests that treatment with drugs that lower production of Abeta can prevent progression of AD but not reverse the disease. While overall encouraging, the results emphasize the importance of early treatment with drugs that inhibit Abeta production.
Citation: Jankowsky JL, Slunt HH, Gonzales V, Savonenko AV, Wen JC, et al. (2005) Persistent amyloidosis following suppression of Ab production in a transgenic model of Alzheimer disease. PLoS Med 2(12): e355.
California Institute of Technology
Mail Code 156-29
1200 E. California Blvd.
Pasadena, CA USA 91125
Johns Hopkins University School of Medicine
558 Ross Research Building
1721 E. Madison Ave.
Baltimore, MD USA 21205
PLEASE MENTION THE OPEN-ACCESS JOURNAL PLoS MEDICINE (www.plosmedicine.org) AS THE SOURCE FOR THESE ARTICLES AND PROVIDE A LINK TO THE FREELY-AVAILABLE TEXT. THANK YOU.
All works published in PLoS Medicine are open access. Everything is immediately available without cost to anyone, anywhere--to read, download, redistribute, include in databases, and otherwise use--subject only to the condition that the original authorship is properly attributed. Copyright is retained by the authors. The Public Library of Science uses the Creative Commons Attribution License.