Research Reveals How Adult/Progenitor Cells Repair Tissue

Medical News Today, May 3, 2007

Stem/progenitor cells acquired from a patient’s own bone marrow can enhance the repair of damaged tissues within the body. However, the manner in which stem cells are able to accomplish this has been a mystery. Now, Tulane University’s Center for Gene Therapy and Dr. Darwin J. Prockop’s new studies are helping to unveil the process.

It was understood that stem cells could differentiate and replace injured cells in the body. But research has revealed that stem cells that are already present in injured tissue are also coerced into proliferating and differentiating, helping to boost the malfunctioning mitochondria by transferring mitochondrial DNA to the local cells. Dr. Prockop says that new and innovative strategies for developing new treatments for a wide range for diseases should become possible with the understanding of how the different mechanisms of the stem/progenitor cells work. Potential risks could be averted and existing treatments could also be enhanced with the new knowledge.

Two series of experiments were described by Dr. Prockop in Washington D. C. at the Association of Anatomists meeting (part of Experimental Biology 2007).

Using immunodeficient mice, human stem/progenitor cells were injected into the hippocampal region of the brain in the first experiment. Increased differentiation and growth was observed in the stem cells usually found in the brains of mice and other animals. This was due to the introduction of the human stem/progenitor cells in the brain

Human stem/progenitor cells traveled to and engrafted themselves in the pancreas in a second study where the cells were intravenously infused into mice that had been modified to have a disease comparable to human diabetes. An increase in islet cell production was recorded as a direct consequence of the increased growth of stem cells that typically reside in the pancreas. This decreased the blood sugar in the mice since the production of insulin was increased. Within 24 hours, some tissue damage can for the most part disappear thanks to the administered cells conducting their repair actions.

The cells could not be found in normal mice that had received similar injections, but even after a month, they were still present in the mice with diabetes. The stem/progenitor cells also engrafted into the diabetes mice kidneys. This was a pleasing surprise to the researchers. Diabetes frequently results in microscopic damage to the kidney, and the stem/progenitor cells were able to repair the damage.

Approximately 8 million people in the United States alone are afflicted with kidney failure due to their constant and deteriorating diabetic conditions. Acquiring healthy cells form bone marrow is easily done, so Dr. Prockop believes that the outcome of his studies suggest probable new treatments for those suffering from diabetes.

There are more than 1,000 patients presently enrolled in U.S. clinical trials who are using these same cells taken from their own bone marrow to treat cardiovascular conditions as well as may other conditions. Dr. Prockop is happy that his research has helped to clarify how the bone marrow stem cells being used in these trials are actually helping to restore the health of these patients.

“For such patients, the experimental treatment is their only option, but as the treatments are made available to larger numbers of people across a variety of different diseases it will be increasingly necessary to proceed carefully,” says Dr. Prockop

He added that good fundamental science research would be critical to ensure safety and good data.

The only National Institutes of Health-designated center to distribute human and mice stem cells is The Tulane Center for Gene Therapy. The samples are taking from the bone marrow of healthy volunteers. Many research studies all are using well-standardized cells with more than 270 scientists in countries around the world including the United States using Tulane cells.