Once we can coax stem cells to go into places in the body and repair decayed tissue we are well on the way toward achieving the ability to do full body rejuvenation. Granted, we'll need other capabilities as well. But the ability to coax and direct stem cells is going to be one of the key pieces of the rejuvenation puzzle. With that in mind, this report about a special class of adult stem cells which can repair muscles is intriguing. Adult myoendothelial stem cells isolated from blood vessel walls can form muscle strands.
In a study using human muscle tissue, scientists in Children's Stem Cell Research Center - led by Johnny Huard, PhD, and Bruno Péault, PhD - isolated and characterized stem cells taken from blood vessels (known as myoendothelial cells) that are easily isolated using cell-sorting techniques, proliferate rapidly and can be differentiated in the laboratory into muscle, bone and cartilage cells.
These characteristics may make them ideally suited as a potential therapy for muscle injuries and diseases, according to Drs. Huard and Péault. Results of the study are published in the September issue of the journal Nature Biotechnology.
"Finding this population of stem cells in a human source represents a major breakthrough for us because it brings us much closer to a clinical application of this therapy," said Dr. Huard, the Henry J. Mankin Professor and vice chair for Research in the Department of Orthopaedic Surgery at the University of Pittsburgh School of Medicine. "To make this available as a therapy, we would take a muscle biopsy from a patient with a muscle injury or disease, remove the myoendothelial cells and treat the cells in the lab. The stem cells would then be re-injected into the patient to repair the muscle damage. Because this is an autologous transplant, meaning from the patient to himself, there is not the risk of rejection you would have if you took the stem cells from another source."
Muscles shrivel with age. Can myoendothelial stem cells restore muscles to something approaching their youthful glory? One problem is going to be that the myoendothelial stem cells will also age and myoendothelial stem cells isolated from a 70 or 80 year old might grow slowly and form tired muscle fibers.
But combine isolation of myoendothelial stem cells from an old body with some gene therapies to repair those stem cells and youthful stem cells for body repair could become available. How to develop those cellular rejuvenating gene therapies will probably turn out to be the hardest problem to solve to make adult stem cells fully useful in rolling back the ravages of aging.
Other types of adult stem cells can also form muscle. But the other types of adult stem cells form muscle much less efficiently.
Working in dystrophic mice while searching for a cure for Duchenne muscular dystrophy (DMD), Dr. Huard's laboratory team first identified a unique population of muscle-derived stem cells with the ability to repair muscle 8 years ago.
Dr. Péault, a professor in the Department of Pediatrics, Cell Biology and Physiology at the University of Pittsburgh School of Medicine, recognized the importance of determining the origin of these muscle-derived stem cells. His team applied, among others, techniques of confocal microscopy and cell sorting by flow cytometry which led to the discovery in human muscle biopsies that these myoendothelial cells are located adjacent to the walls of blood vessels.
According to their study, myoendothelial cells taken from the blood vessels are much more efficient at forming muscle than other sources of stem cells known as satellite and endothelial cells.A thousand myoendothelial cells transplanted into the injured skeletal muscle of immunodeficient mice produced, on average, 89 muscle fibers, compared with 9 and 5 muscle fibers for endothelial and satellite cells, respectively. Myoendothelial cells also showed no propensity to form tumors, a concern with other stem cell therapies.
These researchers are chasing after better treatments for Duchenne muscular dystrophy (DMD). The development of stem cell treatments for DMD will inevitably lead to stem cell treatments to treat aged muscles. That is the way many rejuvenation therapies will come about. Efforts to repair damage caused by trauma, infection, and genetic defects will produce therapies that work to repair the damage caused by aging.
|Share |||Randall Parker, 2007 September 18 11:37 PM Biotech Stem Cells|