I am very happy for those mice, and this may be a wonderful breakthrough
discovery for humans later on, but until I see it or hear of a new drug
being released for human beings for this purpose, I don't want to get my
hopes all worked up about it.   Sorry to sound a wet blanket about it.

As I understand it, beta amyloid protein forms aggregates or
clumps in the neurons.  These clumps are too large to stay
in solution.  They crystallize out as solids or "plaques".  The
plaques damage structures in the cell, for example the plasma
membrane - which must be intact in order to communicate
signals in the brain.

If the cell is still alive, that is, if the nucleus and some other
vital structures are still functioning, then damage in the periphery
of the cell can be naturally repaired if the plaques can be
disolved.  Neurons are gigantic cells.  They have a small
nucleus like other cells, but great amounts of cytoplasm and
membrane.  So peripheral damage probably occurs for
quite a while before the nucleus and other central organelles
like mitochondria are damaged enough to kill the cell.

Once the cell is dead, it's gone and won't come back,
though other cells may take up the workload for it.  But
dead nerve cells can't be resuscitated and, except for
the partial and poorly understood phenomenon of reserve
stem cell differentiation, can't be replaced by new cells.

However peripheral damage can be repaired, existing neurons
can take up some of the work load, and there is even some
evidence that undifferentiated stem cells still remaining in the
brain can be stimulated to become new neurons - though
no one yet knows when or why that happens.

So, for the mouse or human with mild Alzheimer's damage,
I'd guess that recovery of function is possible.  For later stage
patients who have already experienced significant amounts of
cell death, it's too late to get back to normal - though they might
be stabilized and regain a bit of function if the disease were
cured.

At least that's my non-expert take on all this.

   Alan

I really wish that something like this would ultimately happen, but
there's a heck of a lot of distance between mice and humans.  But let
there be no question, I hope it does become a reality within our
lifetimes.  I just get so tired of hearing such good news and then
seeing that it's really only good news if you're a rodent.

Charles R. Whealton
Charles Whealton @ pleasedontspam.com