Wednesday, March 3, 2010

Eyes, brains and sea squirts

In 2005 scientists discovered a way to predict who is at risk of Alzheimer's by looking at the lens inside their eye.  As we age our lenses get cloudy over time leading to the formation of cataracts which we can replace with an artificial lens when things get too murky.  There is another type of cloudiness, however, that is caused by the deposition of the same proteins that are believed to play a major role in the development of Alzheimer's disease (AZ). A special ophthalmoscope is needed to identify the amyloid deposits.  Yet another way to get a hint of the pain to come but what of potential new treatments?

Firstly, the humble sea squirt (Ciona intestinalis) offers a possible model for screening new compounds that might inhibit the formation of plaques and tangles that characterize AZ as we know it.  The marine creatures are likely our closest non-vertebrate relatives and share 80% of our genes  (don't get too excited - we share about 98% with chimps). Sea squirt tadpoles share all the known genes for the formation of plaques and tangles and can be stimulated, with the introduction of a mutant protein, to form not only plaques and tangles in one day, but also behavioral defects that can be reversed with an experimental anti-plaque forming drug.  This novel method, development by Bob Zeller and Mike Verata at the San Diego State University, is one of the most interesting and promising steps forward in the quest for AZ drugs.  I wonder if the little guys (the sea squirt tadpoles that is), can help model Lewy Body Disease too?

In other news, a potential new treatment for Alzheimer's made by Pfizer was nixed today by the FDA. The drug, Dimebon (that sounds  a bit like time-bomb if I am pronouncing it correctly) did not show improved cognition or overall functioning in early- to mid-stage AZ patients.  Analysts had been mixed on their expectations, with The Day article citing anticipated ROI ranging from $1.5 billion to zero. Pfizer was disappointed with the results but not as disappointed as all those folks with the inappropriately cloudy lenses that are now anxiously awaiting news of a cure for their impending AZ...
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