The various physical maladies that affect the human heart are the subject of a great deal of stem cell research. Several of our sector companies are trying therapies using a variety of stem cells from a variety of sources. The race is on to see which works best. But, at this stage, no one is even sure exactly what it is the stem cells are doing when they arrive in the vicinity of the damage they are sent to repair, That said, improvement has been shown for several types of damage. Not the perfect cure as yet, but definitely improved function.
The latest candidate stem cells are called myoendothelial cells, so named by Johnny Huard and Bruno Péault at the University of Pittsburgh's McGowan Institute for Regenerative Medicine. Adult human muscle tissue harbors a population of these unusual progenitor cells that can regenerate skeletal muscle more effectively than other known muscle progenitor cells.
Myoendothelial cells reside in the interstitial spaces between muscle fibres, where blood vessels, which are lined by endothelial cells, are abundant. When purified and injected into damaged muscle in immunodeficient mice, myoendothelial cells generated 10 times more muscle fibres than injected endothelial cells did and 18 times as many as did myogenic cells, also known as satellite cells. Though not as effective as freshly collected cells, myoendothelial cells that had been cultured for up to 6 weeks could still regenerate muscle. New myofibres persisted up to 4 months after transplantation.
Huard and a team of researchers at Children’s Hospital of Pittsburgh (of University of Pennsylvania Medical Center) transplanted myoendothelial stem cells purified from human muscle-derived blood vessels into the hearts of mice that had heart damage similar to that which would occur in people who had suffered a heart attack.
These transplanted myoendothelial cells repaired the injured muscle, stimulated the growth of new blood vessels in the heart and reduced scar tissue from the injury, thereby dramatically improving the function of the injured left ventricle.
“This study confirms our belief that this novel population of stem cells discovered in our laboratory holds tremendous promise for the future of regenerative medicine," said Dr. Huard. "Specifically, myoendothelial cells show potential as a therapy for people who have suffered a myocardial infarction. The important benefit of our approach is that as a therapy, it would be an autologous transplant. This means that for a patient who suffers a heart attack, we would take a muscle biopsy from his or her muscle, isolate and purify the myoendothelial cells, and re-inject them into the injured heart muscle, thereby avoiding any risk of rejection by introducing foreign cells.”
Adapted from the Children's Hospital of Pittsburg announcement.
Comments