Viagra may help protect the hearts of patients suffering from muscular dystrophy, researchers from University of Montreal and Montreal Heart Institute have suggested.
Muscular dystrophy is characterized by weakness and progressive degeneration of the muscles, including the heart muscle. It is caused by a genetic mutation of dystrophin, a protein that acts as the "backbone" of muscular cells.
The study conducted using a mouse model showed that sildenafil protected the heart in mice with Duchenne muscular dystrophy.
"This achievement was a true team initiative and is the culmination of sustained efforts on the part of Dr. Maya Khairallah, who was a doctoral student at the time, and all of the researchers from participating centres," said Dr. Christine Des Rosiers, lead researcher from the Universite de Montreal and the Montreal Heart Institute.
"I'm pleased that my work has sparked interest in an eventual application for humans," says Dr. Khairallah
The researchers explain that the choice of sildenafil was based on their previous studies indicating that the hearts of dystrophic mice do not function as effectively and are more susceptible to stress-induced cell death.
These studies suggested that this might be due to a decrease in the formation of a molecule named cGMP (cyclic guanosine monophosphate).
For the new study, researchers used two different approaches to increase cGMP production in the heart, with the result that the hearts were able to function more effectively and were less susceptible to cell death.
"One of these approaches involved the use of sildenafil, which increased cGMP concentration by preventing its degradation by the phosphodiesterase 5 enzyme," said Dr. Basil Petrof of the Research Institute of the McGill University Health Centre (MUHC)
"Our work had shown for many years the benefits of cGMP on the heart and the present study confirms the therapeutic potential of this molecule", said Dr. Christian Deschepper of the Institut de recherches cliniques de Montréal.
The researchers also made reference of another study showing the beneficial effects of a medication similar to sildenafil on the other muscles of dystrophic mice. Thus, the benefits of this approach may not be limited to the heart.
The study findings are published in the online edition of the Proceedings of the National Academy of Sciences.