New Thinking About Alzheimer's Treatment
Current therapies are the triumph of hope over experience.
Plaque Attacks and Tangled Webs continued...
But whether beta amyloid and tau are the causes of Alzheimer's
disease or a result of it is still unclear.
"Clearly, beta-amyloid and tau pathology are part of the
disease. The question is at what point in the cascade of events these things
come into the picture," Alzheimer's disease research pioneer Zaven
Khatchaturian, PhD, tells WebMD.
Khatchaturian, who is a consultant to other Alzheimer's disease
researchers, formerly headed the Office of Alzheimer's Disease Research at the
National Institute on Aging. He says that while it's encouraging that
anti-amyloid therapies have gotten over the first hump -- safety in humans --
it's still unclear whether these therapies will have a positive effect on the
Khatchaturian says instead of attacking late-stage features of
the disease, it might be possible to intervene at an earlier step, before the
normal brain protein known as amyloid precursor protein (APP) is transformed
into the abnormal form beta amyloid.
"[APP] is a very significant protein in cell-to-cell
communication. It's been around since the fruit fly, and there are different
versions of it, but we don't have any idea about its function. One target may
be that we're looking at the wrong end of the story, that the real story might
be before it gets broken," Khatchaturian says.
Could Stem Cells Stem the Tide of AD?
Although human embryonic stem cells show promise for many
neurological diseases such as Parkinson's disease, Huntington's chorea, spinal
cord injuries, and other conditions, the complexity of Alzheimer's disease and
the difficulty of delivering stem cells to the regions of the brain that are
affected make them impractical for widespread use.
"Stem cells, although they're promising for other diseases,
it's not very likely practically that they'll be used for Alzheimer's disease,
because the way stem cell replacement is practiced in clinical research is by
surgically implanting stem cells into regions of the brain where there has been
degeneration, and that's fairly local in terms of Parkinson's disease and
Huntington's, but for the entire cerebral cortex you're talking about making
dozens of little holes in the skull," says Sam Gandy, MD, PhD, director of
the Farber Institute for Neurosciences at Thomas Jefferson University in
"There is a fairly new area focusing on identification of
stem cells that are still present in the adult brain that weren't thought to be
there," Gandy tells WebMD. "It's conceivable that if there were enough
of those in quantity or you could deliver them, and if they have enough
dividing potential you could stimulate them to replace the dying nerve cells in
their immediate environment, but that still is very complicated."
The job would involve turning on dormant stem cells, getting
them to change into the right kind of cell, and then getting them to move to
the part of the brain where they're needed to repair damage, a series of tasks
that are beyond our current capabilities, Gandy says.
Sheldon L. Goldberg, president and CEO of the Alzheimer's
Association, tells WebMD that few or none of the 800 or so grant applications
for research funding received by the association this year have been for stem