Researchers at the University of Texas, Arlington were developing a nanoparticle injection to reduce scar tissue formation at catheter implantation sites when they discovered a 200% increase in stem cell production in these areas. “Our initial focus was to isolate cells which are recruited to the surface of medical implants in the peritoneal cavity,” said lead researcher Liping Tang, a professor of bioengineering, to BioTechniques. “Surprisingly, we later found that many of these immigrated cells possess stem cell properties and were highly proliferative.”
Tang says implantation of medical devices like catheters can cause inflammation and scar tissues that cause the implant to fail. “To do away [with] using catheters, we have developed several groups of nanoparticles which can be injected into animals via syringe that also trigger the recruitment of stem cells,” said Tang. “Stem cells are often recruited to the injured site to facilitate tissue repair. We believe that the implantation of catheters and the nanoparticles somehow trick the body to feel that there is an injury and send in the stem cells to the implantation site.”
In a press release, the University of Texas, Arlington said that bone marrow is an abundant source of adult stem cells, producing 500,000 stem cells per 15 milliliters of bone marrow fluid. Tang’s use of injected nanoparticles yielded more than 100 million stem cells from one subject, and though the research was conducted in mice, a human trial is being prepared. The technique could be used to enhance heart muscle regeneration in patients who have suffered a heart attack or grow new bone for trauma patients, said Tang.
Stem cell research has typically relied on the use of viable embryos, which has inherent ethical drawbacks as well as issues surrounding a recipient's immune response against donated cells. Though adult stem cells do not harm the cell donor, this method is limited due to the differentiated nature of the cells. According to Tang, this serendipitous discovery will provide support to those who believe embryonic stem cell research is unethical.
“It is well documented that the source of embryonic stem cells is controversial and the risk associated with the potential immune responses to embryonic stem cells is huge,” said Tang. “The use of adult stem cells in tissue repair would [likely] generate the best outcome without immune rejection, although [a] limited number and source of adult stem cells has been the bottleneck of adult stem cell therapy. I believe that our method could be the breakthrough needed to further adult stem cell therapy.”
The research was presented at the Society for Biomaterials Annual Meeting and Exposition in April 2009. The University of Texas, Arlington formally announced the research findings on Nov. 3, 2009. A patent on the method is pending. Research was funded by the National Institutes of Health.