Renaissance in Medicine
Part 4 of 5
2017/03/24 Mayo Clinic By – Megan McKenzie
Renaissance means rebirth or regeneration. Every few generations, medicine takes a major turn. We’re at one of those junctures now with regenerative medicine — where healing is triggered from within the human body. It’s bringing a whole new universe to how physicians provide care.
Three approaches to regenerative medicine
Diseases, injuries and birth defects are treated using three approaches by the Center — regeneration, rejuvenation and replacement.
1 Regeneration — delivering specific types of cells or cell products to diseased tissues or organs, where they will ultimately restore function.
Regeneration can be achieved using cell-based therapies or by using molecules made by cells, like growth factors or antibodies.
Bone marrow transplant is a cell-based therapy that’s been in use for half a century. Similarly, umbilical cord blood transplants have helped patients for decades. Both of these sources of blood-forming stem cells are useful for treating diseases like blood cell-related cancers.
More than half of the clinical trials that fall under the Center for Regenerative Medicine’s purview involve the use of stem cell-based therapies of one kind or another. Dennis Wigle, M.D., Ph.D., a thoracic surgeon at Mayo Clinic in Minnesota, is performing one such trial aimed at regenerating lung tissue. He and his team are working to develop new therapies for people with a wide range of lung diseases, including chronic obstructive pulmonary disease and cystic fibrosis. First they collect cells from the skin of people with various end-stage lung diseases and then they turn them into patient-specific stem cells, and grow them into lung cells with a view towards delivering them back to the patient.
In a cell product-based therapy trial, Morie Gertz, M.D., a hematologist also at Mayo Clinic in Minnesota, is treating a disease called amyloidosis, in which abnormal proteins are deposited in tissues. Usually, all the proteins in the body are biodegradable and recyclable, but amyloid proteins cannot be broken down, and as a consequence, they build up in the heart, kidney, liver and nerves, sometimes causing multiple organ failure. Dr. Gertz’s team is using monoclonal antibodies, a cell product made in the Cellular Therapy Laboratory, to mimic the body’s own immune system and to dissolve these deposits.
2 Rejuvenation — boosting the body’s natural ability to heal.
Regenerative medicine uses rejuvenation to remodel cells and tissues, promoting self-healing processes, something like the way bones mend themselves.
One illness Mayo Clinic is treating by rejuvenation is renal artery stenosis, a narrowing of the blood vessels carrying blood to the kidneys, usually due to hardening of the arteries. In a patient with renal artery stenosis, less blood reaches the kidneys, which the body misinterprets as low blood pressure. This signals the release of hormones from the kidneys, leading to an increase in blood pressure (hypertension) that can damage one or both kidneys. Renal artery stenosis may account for up to ten percent of the 50 million people in the U.S. who have hypertension.
Even if the high blood pressure is addressed, kidney function does not usually return on its own. “The problem is that once the inflammation gets started, it gets kind of hard to put it out,” explains Stephen Textor, M.D., a hypertension specialist at Mayo Clinic in Minnesota. His team, composed of nephrologists, radiologists, laboratory medicine specialists and molecular biologists, is using adult stem cells to boost tissue repair in kidneys damaged by renal artery stenosis. In a clinical trial, they have observed blood flow and function returning to rejuvenated kidneys. “It’s steering tissues away from inflammation and wedging them into repair mode,” says Dr. Textor.
3 Replacement — using healthy cells, tissues or organs to replace damaged ones.
While formidable, organ transplantation is in great demand. Right now, more than 120,000 Americans are waiting for a transplant from a living or deceased donor.
Transplants engineered from a patient’s own cells offer opportunities to overcome the donor shortage, and minimize the risks associated with organ rejection.
Engineered transplants start with patient-specific anatomical data, which is already used routinely to 3D print complex, computer-designed medical devices. Information is taken from a computerized tomography (CT) scan and, layer by layer, it’s printed out as a perfect model of, for example, a patient’s hip joint. That model can then be sent to a manufacturer to make a custom-designed implant.
Taking it to the next level, 3D printers can also make scaffolds for tissue engineering. The idea is basically to seed cells into a matrix to generate a patient-specific implant — this is called bioprinting.
Because tissues and organs are made up of many cell types in varying patterns, scientists are using bioprinters to mimic living tissue by varying the scaffold properties and the cell types seeded within them. Bioprinting is still experimental, but soon tissues like skin, bone, cartilage, muscles, valves, vessels and even nerves will be (re)generated routinely by combining natural or engineered stem cells with custom, 3D scaffolds. Eventually, transplantable organs like the liver will also be grown in the lab. “It sounds like science fiction,” says Dr. Wigle, “but the truth is that we’re within inches of clinical reality.”
Also at Mayo Clinic in Minnesota, cardiologist Amir Lerman, M.D. is working towards bioprinting heart valves. Heart valve problems can be present at birth or caused by infections, heart attacks, or heart disease or damage; valves can be too tight and not allow enough blood to flow through them, or they can prolapse and leak. In the U.S. alone, about 65,000 heart valves are replaced every year, mostly using prosthetics built from materials like plastic and metal.
Among other problems, blood tends to stick to these valves, creating dangerous blood clots. If successful, the valves Dr. Lerman’s team is working on will be a big improvement over even the best possible prosthetic valve, because they’ll have the ability to remodel, regenerate and grow.
Hand in hand with bioprinting, Dr. Lerman’s team is also developing bioreactors to test the valves in a physiologically-relevant environment in the lab, making it possible for the cells seeded into their printed scaffolds to proliferate, migrate, align and differentiate, and thus to become a fully functional tissue system upon implantation.
Stem Cell Centers in India, affiliated with Global Stem Cells Group of Miami, Florida, has been in the forefront of regenerative medicine and cellular therapies for several years. We are a unique network of highly skilled physicians. Our mission is to bring innovative stem cell therapy to the forefront of medicine and enhance the quality of life for our patients around the world. To learn more about stem cells and how you can take the first step towards recovery, call +91 9888936107 or write us at email@example.com