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New approach to protect the hearts of patients with muscular dystrophy
May 13, 2008A team of researchers has recently shown that the administration of sildenafil protects the heart in mice with Duchenne muscular dystrophy. This study was led by Dr. Christine Des Rosiers from the Université de Montréal and the Montreal Heart Institute, in collaboration with Dr. Basil Petrof of the Research Institute of the McGill University Health Centre (MUHC) and Dr. Christian Deschepper of the Institut de recherches cliniques de Montréal. The study findings are published today in the online edition of the Proceedings of the National Academy of Sciences.
"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," says Dr. Des Rosiers.
"I'm pleased that my work has sparked interest in an eventual application for humans," says Dr. Khairallah. The study received financial support from the Canadian Institutes of Health Research, the Fonds de la recherche en santé du Québec, the Heart and Stroke Foundation of Canada, the Muscular Dystrophy Association and the National Heart, Lung and Blood Institute in the U.S.
Improved cardiac function and reduced cell death
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 may be due to a decrease in the formation of a molecule named cGMP (cyclic guanosine monophosphate).
In the present 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," explains Dr. Petrof, who works at the MUHC's Meakins-Christie Laboratories. "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", adds Dr. Deschepper.
About muscular dystrophy
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. This disease, whose most common forms are those of Duchenne and Becker, has an incidence of one in 6,000 births and a prevalence of roughly one in 3,600 boys.
The first signs of muscular weakness appear at roughly age 5, leading to a progressive loss in the ability to walk by the age of 13. Cardiac problems can occur at the age of 10 and progress very quickly, affecting the majority of patients by the age of 20. They are also an important cause of death among patients with muscular dystrophy.
"Research on this disease used to focus on the degeneration of skeletal muscles," says Dr. Des Rosiers, "but it is important to take into account all muscular problems, including cardiac problems, when treating these patients so that we can improve their quality of life."
The researchers point to 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. Sildenafil is already prescribed for erectile dysfunction and pulmonary hypertension. However, Dr. Petrof mentions that "further clinical studies will be required before Viagra is prescribed to dystrophic young children."
"These experimental results give us hope that one day it will be possible to treat with this approach cardiac problems in patients with muscular dystrophy, and perhaps even treat other heart diseases," Dr. Jean-Claude Tardif, director of the Montreal Heart Institute Research Centre and professor of medicine at the Université de Montréal. "It also demonstrates our researchers' commitment to conducting basic research that has the potential to transform the practice of medicine."
University of Montreal
Improved cardiac function and reduced cell death
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 may be due to a decrease in the formation of a molecule named cGMP (cyclic guanosine monophosphate).
In the present 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," explains Dr. Petrof, who works at the MUHC's Meakins-Christie Laboratories. "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", adds Dr. Deschepper.
About muscular dystrophy
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. This disease, whose most common forms are those of Duchenne and Becker, has an incidence of one in 6,000 births and a prevalence of roughly one in 3,600 boys.
The first signs of muscular weakness appear at roughly age 5, leading to a progressive loss in the ability to walk by the age of 13. Cardiac problems can occur at the age of 10 and progress very quickly, affecting the majority of patients by the age of 20. They are also an important cause of death among patients with muscular dystrophy.
"Research on this disease used to focus on the degeneration of skeletal muscles," says Dr. Des Rosiers, "but it is important to take into account all muscular problems, including cardiac problems, when treating these patients so that we can improve their quality of life."
The researchers point to 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. Sildenafil is already prescribed for erectile dysfunction and pulmonary hypertension. However, Dr. Petrof mentions that "further clinical studies will be required before Viagra is prescribed to dystrophic young children."
"These experimental results give us hope that one day it will be possible to treat with this approach cardiac problems in patients with muscular dystrophy, and perhaps even treat other heart diseases," Dr. Jean-Claude Tardif, director of the Montreal Heart Institute Research Centre and professor of medicine at the Université de Montréal. "It also demonstrates our researchers' commitment to conducting basic research that has the potential to transform the practice of medicine."
University of Montreal
Muscular Dystrophy Current Events and Muscular Dystrophy News RSSExon-skipping drug prevents muscle wasting, maintains muscle function in dystrophin deficient mice
An exon skipping PPMO has demonstrated dramatic effects in the prevention and treatment of severely affected, dystrophin and utrophin-deficient mice, preventing severe deterioration of the treated animals and extending their lifespan.
To regenerate muscle, cellular garbage men must become builders
For scientists at the European Molecular Biology Laboratory (EMBL) in Monterotondo, Italy, what seemed like a disappointing result turned out to be an important discovery.
Zoo volunteers help explain mysteries of the genome
As the University of Leicester approaches the 25th anniversary of the discovery of DNA fingerprinting (September 10), Leicester geneticists interested in a particular type of DNA are receiving some help from an unusual band of assistants.
Small molecule inhibits pathology associated with myotonic dystrophy type 1
Researchers at the University of Illinois have designed a small molecule that blocks an aberrant pathway associated with myotonic dystrophy type 1, the most common form of muscular dystrophy.
Researchers identify new function for protein missing in Duchenne muscular dystrophy
Researchers at the University of Minnesota and National Institutes of Health have identified a new function for the protein missing in people with the most common and ultimately lethal form of childhood muscular dystrophy.
Sticky protein helps reinforce fragile muscle membranes
A new study by scientists at the University of Iowa shows why muscle membranes don't rupture when healthy people exercise.
Stem cell surprise for tissue regeneration
Scientists working at the Carnegie Institution's Department of Embryology, with colleagues, have overturned previous research that identified critical genes for making muscle stem cells.
Researchers make progress toward early identification of muscular dystrophy
The saying "Knowing is half the battle" is never more true than when discussing early treatment of disease. Muscular dystrophy is one such disease where patients can benefit from early treatment. Now, new research is moving doctors and scientists closer to disease diagnosis in advance of patient symptoms.
Jumping genes discovery 'challenges current assumptions'
Jumping genes do most of their jumping, not during the development of sperm and egg cells, but during the development of the embryo itself.
New therapy substitutes missing protein in those with muscular dystrophy
Researchers at the University of Minnesota Medical School have discovered a new therapy that shows potential to treat people with Duchenne muscular dystrophy, a fatal disease and the most common form of muscular dystrophy in children.
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Muscular Dystrophy (The Facts) by Alan E.H. Emery (Author) The muscular dystrophies are a group of genetic diseases that severely affect children and adults. For sufferers and their family, the illness presents enormous physical and psychological challenges. Written specifically for people with muscular dystrophy and their families, this book answers many of the questions asked about how and why muscular dystrophy occurs, and how it will affect the life of a recently diagnosed child. As well as presenting the reader with advice and an explanation of muscular dystrophy, the book also guides the reader towards further information on societies and support groups around the world, and reliable internet resources. It also contains a full glossary to aid the reader in their understanding of the disease. The different types of... |
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Muscular Dystrophy in Children: A Guide for Families by Irwin M. Siegel (Author) Written for children with muscular dystrophy (MD) and their families, friends and teachers, this book is a guide through the often-frightening labyrinth of medical care that follows the diagnosis of MD. Forthright, clear, supportive and empowering, the book helps readers understand the significance of the signs and symptoms of the disease, treatment options, the disease's probable course and what may affect it, and choices in directing therapy. This incomparable guide covers: * The diagnosis of childhood muscular dystrophy Early childhood Prepuberty Fractures Adolescence Late problems Caregiver's self-help guide New research Suggestions for further reading. |
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Muscular Dystrophy: theFacts by Alan Emery (Author) European Neuromuscular Centre, Baarn, The Netherlands. Discusses living with muscular dystrophy and coping with its physical effects. Written for people with this illness and their families, it answers many questions asked by those diagnosed with muscular dystrophy. Previous edition: c1994. Softcover. |
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