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Saturday, November 29, 2008
By David Templeton, Pittsburgh Post-Gazette
A local doctor and his research team are ready to test a repair kit for the human heart, now that they've proved that a similar stem-cell procedure helped repair human bladders.
If similar results occur in humans as happened in mice, the process could be used to prevent scar tissue from forming after a heart attack occurs. It also could bolster blood flow to the injured area to promote healing.
Success in repairing heart muscle by using human stem cells in mice is outlined in a study to be published Tuesday in the Journal of the American College of Cardiology. The team led by Johnny Huard, director of the Stem Cell Research Center at the John G. Rangos Sr. Research Center at Children's Hospital of Pittsburgh of UPMC, not only discovered the myoendothelial stem cell in question but also performed the research in mice.
"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, who's also a professor and vice chairman for research in the Department of Orthopaedic Surgery at the University of Pittsburgh School of Medicine.
The use of myoendothelial stem cells also shows potential to repair muscle, bone and cartilage and in time could be used to treat Duchenne muscular dystrophy, sports and military injuries, and even arthritis.
Adding to the pluses, the stem cells in question exist inside the patient's blood vessels of skeletal muscle, which prevents rejection. Stem cells can be recovered from a small biopsy of the patient's bicep, quadricep or other skeletal muscle, then isolated, purified and allowed to proliferate in vast quantities before being injected into that patient's heart muscle.
"When you inject them into the heart, it blocks scar tissue and promotes blood vessel formation because [the stem cells] come from the blood vessels of muscles," Dr. Huard said.
The site of heart attack damage is a harsh environment for muscle cells because the injured area lacks enough blood vessels to repair the damage. "That's why repair doesn't occur and most cells die," Dr. Huard said.
But myoendothelial stem cells -- adult stem cells, rather than those taken from human embryos -- can be injected in great numbers, which survive in the site damaged by a myocardial infarction, or heart attack. They prevent scar tissue from forming and help sustain blood vessels in the damaged area.
In mouse studies, six weeks after the injection of the stem cells, hearts functioned 40 to 50 percent more effectively than those treated with myoblasts, another type of muscle cell. The procedure went a long way to returning the heart to its condition prior to the heart attack, Dr. Huard said.
Already the procedure of injecting similar stem cells into the neck of the human bladder has been used to repair bladder damage that causes incontinence. That research, Dr. Huard said, proves that the treatment is safe, which should help expedite getting Food and Drug Administration approval to begin clinical trials for the heart procedure.
"That's why we're going into human clinical trials, because it significantly improved cardiac function, and you don't get a scar in the heart," Dr. Huard said. "That's the result we want."
If the success bears out in human hearts, he said, those facing a high risk of a heart attack could have their own stem cells harvested and kept in frozen storage in case they suffer problems later in life. Because the most robust stem cells most likely are found in umbilical cords, or from small muscle biopsies in newborns, it could prove beneficial to harvest those cells at birth and put them into long-term storage.
Having a full supply of myoendothelial stem cells available in advance is important because the sooner the treatment occurs after a heart attack, the better the results, he said.
"We're very excited about this," Dr. Huard said. While human clinical trials are needed to prove its effectiveness in humans, "we are as hopeful as we can be," he said.
By David Templeton, Pittsburgh Post-Gazette
A local doctor and his research team are ready to test a repair kit for the human heart, now that they've proved that a similar stem-cell procedure helped repair human bladders.
If similar results occur in humans as happened in mice, the process could be used to prevent scar tissue from forming after a heart attack occurs. It also could bolster blood flow to the injured area to promote healing.
Success in repairing heart muscle by using human stem cells in mice is outlined in a study to be published Tuesday in the Journal of the American College of Cardiology. The team led by Johnny Huard, director of the Stem Cell Research Center at the John G. Rangos Sr. Research Center at Children's Hospital of Pittsburgh of UPMC, not only discovered the myoendothelial stem cell in question but also performed the research in mice.
"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, who's also a professor and vice chairman for research in the Department of Orthopaedic Surgery at the University of Pittsburgh School of Medicine.
The use of myoendothelial stem cells also shows potential to repair muscle, bone and cartilage and in time could be used to treat Duchenne muscular dystrophy, sports and military injuries, and even arthritis.
Adding to the pluses, the stem cells in question exist inside the patient's blood vessels of skeletal muscle, which prevents rejection. Stem cells can be recovered from a small biopsy of the patient's bicep, quadricep or other skeletal muscle, then isolated, purified and allowed to proliferate in vast quantities before being injected into that patient's heart muscle.
"When you inject them into the heart, it blocks scar tissue and promotes blood vessel formation because [the stem cells] come from the blood vessels of muscles," Dr. Huard said.
The site of heart attack damage is a harsh environment for muscle cells because the injured area lacks enough blood vessels to repair the damage. "That's why repair doesn't occur and most cells die," Dr. Huard said.
But myoendothelial stem cells -- adult stem cells, rather than those taken from human embryos -- can be injected in great numbers, which survive in the site damaged by a myocardial infarction, or heart attack. They prevent scar tissue from forming and help sustain blood vessels in the damaged area.
In mouse studies, six weeks after the injection of the stem cells, hearts functioned 40 to 50 percent more effectively than those treated with myoblasts, another type of muscle cell. The procedure went a long way to returning the heart to its condition prior to the heart attack, Dr. Huard said.
Already the procedure of injecting similar stem cells into the neck of the human bladder has been used to repair bladder damage that causes incontinence. That research, Dr. Huard said, proves that the treatment is safe, which should help expedite getting Food and Drug Administration approval to begin clinical trials for the heart procedure.
"That's why we're going into human clinical trials, because it significantly improved cardiac function, and you don't get a scar in the heart," Dr. Huard said. "That's the result we want."
If the success bears out in human hearts, he said, those facing a high risk of a heart attack could have their own stem cells harvested and kept in frozen storage in case they suffer problems later in life. Because the most robust stem cells most likely are found in umbilical cords, or from small muscle biopsies in newborns, it could prove beneficial to harvest those cells at birth and put them into long-term storage.
Having a full supply of myoendothelial stem cells available in advance is important because the sooner the treatment occurs after a heart attack, the better the results, he said.
"We're very excited about this," Dr. Huard said. While human clinical trials are needed to prove its effectiveness in humans, "we are as hopeful as we can be," he said.
