WASHINGTON (Reuters) -
A Canadian study involving mice
shows that anti-impotence pills might protect the hearts of
people with a common form of muscular dystrophy, researchers
said on Monday.
Canadian researchers gave sildenafil, the active ingredient
in drug maker Pfizer Inc's Viagra, to mice with an animal
version of Duchenne muscular dystrophy, and found that it
improved their heart performance.
They said it would be premature to give Viagra to people
with the disease, but said the results indicate the drug
potentially could be used to prevent or delay heart failure in
children with Duchenne muscular dystrophy.
The mice were given doses of the drug comparable to those
to treat erectile dysfunction in men. The study,
published in the of the National Academy of
Sciences, showed that sildenafil cut the levels of damage to
contracting heart muscle cells.
“If you don't give the sildenafil, the heart of these mice
doesn't function as well as normal mice, and they are more
susceptible to stress-induced cell death,” said researcher
Christine Des Rosiers of the Montreal Heart Institute.
She said in an interview the drug worked to improve heart
performance in the mice by preventing the breakdown of a
naturally occurring chemical. Called cyclic guanosine
monophosphate, or cGMP, it is involved in a number of cellular
signaling pathways, the researchers said.
Other impotence drugs also affect the chemical cGMP,
including vardenafil, sold by Schering Plough under the brand
name Levitra, and tadalafil, sold by Eli Lilly and Co. under
the brand name Cialis.
Duchenne muscular dystrophy is an inherited wasting disease
characterized by weakness and progressive of the
muscles, including the heart muscle. It begins in the legs and
pelvis, and later affects the whole body. Most people with the
disease must use a wheelchair by about age 12.
It is caused by a genetic mutation of dystrophin, a protein
vital to muscle cells.
Heart problems can appear at around age 10 and they
progress quickly, affecting most people with the disease by age
20. These heart problems are an important cause of death among
patients with muscular dystrophy.
Sildenafil was developed as a heart drug and is widely
prescribed for erectile dysfunction as well as pulmonary
. The researchers said discussions are under way
about possible future studies using the drug in patients with
muscular dystrophy.
“There's a lot of information on this drug that shows it
appears to be relatively safe in adults,” Des Rosiers said,
while that future human clinical trials are needed
before doctors prescribe it for heart trouble in these
patients. (Editing by Maggie Fox and Doina Chiacu)
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