New Thinking About Alzheimer's Treatment
Current therapies are the triumph of hope over experience.
Plaque Attacks and Tangled Webs continued...
One experimental drug, called Alzhemed, has been shown in
animal and human studies to clear significant amounts of beta amyloid deposits
from the brain. A similar drug, known only as LY450139, has shown similar
effects in humans.
Several companies are also working on vaccines that can
stimulate the body to make antibodies that attack and dissolve beta-amyloid
deposits. Other experimental drugs and vaccines are aimed at treating another
suspected cause of AD, a different protein known as tau, which normally serves
as a building block of nerves. In the brains of people with advanced AD,
strands of twisted tau proteins, called fibrillary tangles, can be found inside
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.