Reattaching Teeth with Adult Stem Cells
Researchers at the University of Illinois at Chicago have shown that they can anchor teeth back in the jaw using adult stem cells. The technique could be widely applicable for replanting teeth lost through gum disease or an accident.
The scientists used adult stem cells obtained from the periodontal ligament of molars extracted from mice. The cells were grown in culture and then seeded onto clean rat molars, then the molars were placed into the tooth sockets of rats. After two to four months, the stem cells aligned and formed new fibrous attachments between the tooth and bone, firmly attaching the replanted tooth into the animal's mouth. Molars that were replanted without adult stem cells were either lost or loosely attached and were reabsorbed by the jaw.
According to senior author Thomas Diekwisch:
"Our strategy could be used for replanting teeth that were lost due to trauma or as a novel approach for tooth replacement using tooth-shaped replicas."
The study was published recently in the journal Tissue Engineering.
Reversing Aging of Muscle Adult Stem Cells
A Joslin Diabetes Center team has shown that treatment of aged mice with a compound can rejuvenate their muscle stem cells. The lab of senior author Amy Wagers developed a way of screening chemicals that would promote regeneration in muscle stem cells from older mice, and identified a compound, A25, that selectively blocks a protein involved in TGF beta signaling, a cellular signaling pathway important to stem cell growth.
The drug had no effect on muscle stem cells in young mice, but in older mice the compound gave old muscle stem cells the regenerative ability of cells from young mice. Because this compound would stimulate cells throughout the body, it would not be useful in humans, but the results do show that stimulation of old muscle adult stem cells is possible. An appropriate compound could potentially be useful to repair wasted or damaged muscle in older people.
The results were presented at the annual meeting of the American Society for Cell Biology in Philadelphia.
Adult Stem Cell Protein Improves Hearts
Duke researchers have shown that applying a protein secreted by adult stem cells can repair heart function and reduce scarring. The group had previously shown that adult mesenchymal stem cells could reduce heart and restore function in rodent hearts. Their newest study looked at the mechanism behind the success of adult stem cells in treating heart damage.
They found that a natural protein, called "secreted frizzled related protein 2 (sfrp2)", was a key factor in the heart repair seen with adult stem cells. In a rat model, they found that application of the protein after heart attack prevented fibrous scarring within two weeks, and began to restore heart function within four weeks.
Dr. Victor Dzau, senior author of the study, said:
"We found that giving the study rats the protein sfrp2 strongly improved heart function in the critical pumping chamber, the left ventricle, after a myocardial infarction. We observed that sfrp2 at therapeutic doses reduced heart muscle death and also directly prevented deposits of collagen, and thus reduced the scarring that can affect heart function."
The results were published in the Proceedings of the National Academy of Sciences.
A Perpetual Adult Stem Cell?
Scientists at the University at Buffalo have engineered adult stem cells that can grow continuously in culture. Normal adult stem cells have a limited lifespan in the laboratory, which frustrates scientists who want to study them over the long term, but does not prevent their being grown and used for current adult stem cell transplants.
The scientists developed the new cell lines by genetically engineering mesenchymal stem cells, a type of adult stem cell from bone marrow that can form other cell types and repair various tissues. They named the new cells "MSC Universal". The new adult stem cells show no evidence of aging in culture, function as normal mesenchymal stem cells, and do not form tumors in animal testing (unlike embryonic stem cells).
According to the project leader, Dr. Techung Lee, an MSC-Universal cell line could be generated from any donor.
"Our stem cell research is application-driven. If you want to make stem cell therapies feasible, affordable and reproducible, we know you have to overcome a few hurdles. Part of the problem in our health care industry is that you have a treatment, but it often costs too much. In the case of stem cell treatments, isolating stem cells is very expensive. The cells we have engineered grow continuously in the laboratory, which brings down the price of treatments."
One of the mechanisms by which adult stem cells help regenerate or repair damaged tissues is by releasing growth factors that encourage existing cells in the human body to function and grow. Lee has previously published evidence showing that injecting adult stem cells into skeletal muscle can stimulate repair of the heart. More recently his lab has identified some of the factors involved in the stimulation of repair, published in the journal Heart and Circulatory Physiology.
The University of Buffalo has applied for a patent to protect Lee's discovery, so there is as yet no publication about the new cells.
Contact: David Prentice
Source: FRC Blog
Publish Date: December 15, 2010
