In a Nut Shell: What are Stem Cells?
Simply put, in your body there are many different kinds of cells, each specialized for its own distinct task. Just as a banker works in a bank and a teacher works in a school, we have cardiac myocytes which are heart muscle cells, and retinal cells that work in eyes and allow us to see. Stem cells are immature cells which have the capability of becoming these more specialized cells. By purifying and amplifying these cells, we have developed an exciting new method to repair organs that are irreversibly damaged by the ravages of disease.
Importantly, adult stem cells can be obtained from adult human bone marrow. When extracted and grown under laboratory conditions, bone marrow stem cells can grow into many different kinds of cells, depending on the laboratory conditions under which they are grown.
How does this work?
Consider this scenario: you have a heart attack. You go to hospital. The doctors treat you and stabilize your condition, but they are unable to actually repair the damage your heart has sustained. Because of this you are at risk for other medical problems.
Doctors at the University of Miami Miller School of Medicine’s Interdisciplinary Stem Cell Institute are working on new therapies to address this specific problem. Using adult stem cells from the bone marrow, early tests have shown that cell-based therapies can reverse the damage your heart has sustained. Because of this, cell-based therapy may in the future improve the quality of life of patients who have had heart attacks. The mission of the Interdisciplinary Stem Cell Institute at the University of Miami is to make this happen as soon as possible and to conduct basic research to help understand exactly how this works.
This scenario, with further research and careful clinical trials, has the potential to be applicable to the repair of damaged liver, lung, spinal cord, and even improve treatments for diabetes.
Will this harm embryos?
These stem cells have never been anywhere near an embryo. They were made and live in adult bone marrow.
More About Stem Cells: Stem Cells 101
Stem Cells are undifferentiated cells that have the potential to differentiate into a variety of different cell types. Most in the news are embryonic stem cells, derived from terminated embryos, but our researchers use stem cells that are isolated from adult bone marrow, with no risk to the donor. In particular, for heart repair, we use mesenchymal stem cells (MSCs) which are found in bone marrow, in muscle, skin and adipose tissue. They are able to differentiate into a number mesenchymal tissues, such as muscle, fibroblasts, bone, tendon, ligament and adipose tissue. They express signature markers that are unique, and easily distinguished from those of hematopoeitic and other types of stem cells.
Following myocardial infarction, heart tissue looses cardiac myocytes, which are irreplaceable nonrenewable cells. To compensate, it undergoes remodeling which results in hypertrophy and scar formation through accumulation of collagen and fibrosis. The heart thus enlarges and this leads to congestive heart failure. The ultimate goal of mesenchymal stem cell therapy is to stimulate repopulation of the damaged region with new heart tissue, and thus delay or prevent the progression from myocardial infarction to total heart failure.
Preliminary experimental and clinical trials have yielded promising results. MSCs, injected into heart tissue using a specialized catheter, were able to differentiate into cardiomyocytes and endothelial cells. In addition, these new cells were able to perform the same function as the cells that were lost due to cardiac infarction. The results thus imply that MSCs are actually differentiating into functional, integrated cardiomyocytes.
The paradigm thus begins to shift , with the emphasis being placed on regenerative medicine. For heart attack, all existing therapies restore blood flow or aim to minimize damage to the heart. Now we can conceive for the first time of reversing the damage caused by the heart attack. Many challenges lie ahead. We need to find the optimal cell, and the best way to deliver it. We must make sure the therapies are safe, and we must fully understand all of the different ways in which cell therapy works. And finally, we need to do the formal and rigorous testing to make sure that the therapies are safe and effective. All of our testing in humans is performed with the approval of the United States Food and Drug Administration.
This strategy is applicable to a wide range of tissue types and diseases. Researchers at the Interdisciplinary Stem Cell Institute are working together not only on finding treatments for heart failure, but also for cancer, diabetes, bone and neurodegenerative diseases.
Stem Cell Therapy – Healing Force of the Future
Some of the millions of people currently living with congestive heart failure could potentially be helped by stem cell therapy, according to the results of a small study presented by researchers at the University of Miami at the American Heart Association‘s annual meeting today.
The study, which was conducted by the Interdisciplinary Stem Cell Institute at the University of Miami Miller School of Medicine, looked at 30 patients with damaged hearts who were treated with stem cell injections.
The study overturned a long-standing medical belief that, heart damage, once incurred, could not be repaired. In fact, the results showed that the innovative treatment reduced the amount of heart damage by a third, built up healthy heart tissue, and remodeled the shape of the ailing heart to look more like a healthy heart.
“Patients who received the cell therapy clearly benefited and the cells from donors are just as safe as those from the recipient,” said Joshua M. Hare, M.D., who is the institute’s and the study’s lead author. The study was significant because it showed stem cell therapy works, “even in patients who had heart attacks several decades before treatment,” he said.
The study looked at stem cells taken from bone marrow. In the research, half of the patients were injected with their own stem cells, and half were given donor stem cells. The study showed that donor cells may turn out to be preferable because using the patient’s own stem cells requires a six-to-eight week delay for harvesting and maturation.
The study, funded by the National Institutes of Health, was the first ever to directly compare the safety and efficiency of this type of cells taken from patients with those provided by a donor.
“If the results of our work continue to hold up in future studies, we can dramatically improve the quality of life for patients who before now had few options,” said Darcy L. DiFede Velazquez, R.N., B.S.N., the institute’s research director, and a study co-author.
Dr. Hare and his team are now planning a larger, placebo-controlled study to determine whether this type of therapy can become a standard treatment people for hearts scarred by heart attacks. Such scarring is the leading cause of debilitating and potentially fatal congestive heart failure and can lead to the need for a heart transplant.
Five million people in the U.S. are currently living with heart failure, and it is listed as a contributor to 287,000 deaths annually. Heart failure is a progressive disease that, in severe cases, can result in the need for a heart transplant.