This seems like important news. Here are excerpts:

"But for more than a quarter-century, researchers have been unable to decide between two explanations. One is that the spread may mean that the disease is transmitted from neuron to neuron, perhaps along the paths that nerve cells use to communicate with one another. Or it could simply mean that some brain areas are more resilient than others and resist the disease longer. The new studies provide an answer. And they indicate it may be possible to bring Alzheimer’s disease to an abrupt halt early on by preventing cell-to-cell transmission, perhaps with an antibody that blocks tau."

"The question of which hypothesis was correct — tau spreading cell to cell, or a bad neighborhood in the brain and cells with different vulnerabilities to it — remained unanswerable. Dr. Hyman said he tried for 25 years to find a good way to address it."

"He and others are also asking if other degenerative diseases spread through the brain because proteins pass from nerve cell to nerve cell. Dr. Hardy thought he saw provocative human evidence that it might be happening in Parkinson’s disease."

Robin


http://www.nytimes.com/2012/02/02/healt ... -find.html

February 1, 2012
Faulty Protein Is Like a Virus in Alzheimer’s
By Gina Kolata
New York Times

It's an extremely important finding, and the studies are very elegant, methodologically. Even more important than the direct findings, they open some possibilities for pre-clinical drug testing in an animal model, for meds that directly attack the tau mechanism.
Laurel

Laurel,

You probably know that there are two clinical trials underway that address tau, not in AD but in PSP (progressive supranuclear palsy). Of course they are addressing tau after lots of damage has already occurred but at least they're going after tau.

Haven't we seen lots of mouse studies that prove to have totally different results once the compounds are tested in humans? Similarly, have we seen mouse studies that show a different mechanism than is seen in humans?

Robin

Hi Robin,

Yes, I'm very interested in the studies of tau modification. But as you say, pretty late in the process.

The interesting thing about these mouse models is that they are using "humanized" mice, so that in principle the findings should generalize more readily. But there have been a lot of disappointments in that world, too. One of my colleagues wrote a paper some years back titled "From Mouse to Man", essentially listing all the reasons why it is so hard to extrapolate from mouse models. We have all sorts of cool new ways to do generate very specific disease models now, but it's still hard to anticipate all the barriers to clinical translation to human treatment.

We keep feeling as if we are just on the edge of tremendous breakthroughs. Big gap, though, between understanding the basic science and having a working drug.
Laurel