Back Home (Betsy)
I told Betsy for years that a cure was on it way for her.
And while it would never have made her whole due to her age it would
help. Well here it is! Just a few years late.
Mouse study shows new therapy may reverse muscular dystrophy
Science News Aug 7 2004 Vol 116 Pg 84
For people with the most common type of muscular dystrophy, one faulty
gene wreaks devastating consequences. Researchers have now found a way to
deliver a working copy of the gene to the entire muscular system in mice that
suffer from the muscle-wasting ailment. With one injection into the
bloodstream, the animals' conditions improved markedly.
"No one's been able to get a delivery system to work very well
before," says Jeffrey S. Chamberlain of the University of Washington in
Seattle. "We were able to show a very significant effect in halting and
reversing this disease."
To the genome of a virus that doesn't trigger an immune response or
replicate in mice or people, the researchers added the dystrophin gene, the
faulty version of which causes Duchenne muscular dystrophy. The investigators
also included a promoter gene that ensured that only muscle cells would
manufacture the protein encoded by the dystrophin gene.
That protein acts like a had
received girder in a building, providing structural support to muscle
cells. Without it, muscle tissue develops holes and tears.
The researchers injected the engineered virus, along with a chemical to
facilitate its diffusion through blood vessels, into mice with muscular
dystrophy. Weeks later, the scientists examined these animals' muscles,
including those in the arms, legs, and ribs, and compared them with muscles of
similar mice that hadn't received an injection.
"The [treated] muscles looked tremendously better under the
microscope," says Chamberlain. He and his colleagues report their results
in the August Nature Medicine.
One injection into the bloodstream spread the virus-and the dystrophin
gene it carries-to skeletal muscles and the heart. "This research shows
that it's possible to deliver a therapeutic gene throughout the body,"
comments Thomas A. Rando of Stanford University, who studies muscle diseases.
"That's been a real hurdle."
Because the dystrophin protein in the test functioned only in muscle
cells, the procedure overcomes an additional obstacle to gene therapy-limiting
a therapeutic gene's activity to the desired cells and tissues.
Other experimental attempts at gene therapy for muscular diseases rely on
local injections directly into muscle, and any beneficial effects are limited
to that area. This research sets a new standard for gene delivery to the entire
muscular system, says Rando.
The same gene-delivery method could prove useful for treating a variety
of muscular disorders, including heart disease and muscle wasting associated
with aging, Rando says.
Adding to the technique's promise is evidence that the virus infiltrated
many organ systems. To target genetic therapies to disorders of organs such as
the liver and kidney, investigators might load viruses with different
combinations of healthy genes and promoters Chamberlain speculates.
While the treatment appears to be safe and effective in mice, it's too
soon to say
Whether it will be suitable for use in people. Chamberlain is
embarking on safety studies in larger mammals and hopes to begin human-safety
studies in a few years.
Well before the results become available, this new method will provide
laboratory and clinical researchers with a powerful new means of gene
delivery, says Kevin P. Campbell of the University of Iowa in Iowa City. -C.