By Gudrun Schultz
MINNESOTA, United States, January 16, 2007 (LifeSiteNews.com) – Researchers at the University of Minnesota have successfully used adult stem cells to replace the immune system and bone marrow of mice, in one of the most significant discoveries of the recent acceleration in adult stem cell research breakthroughs.
The research technique isolated adult stem cells (multipotent adult progenitor cells, or MAPCs) from the bone marrow of adult mice. The cells were reproduced in the lab, and then transplanted into mice that had no immune system due to radiation treatments.
“The cells not only survived when transplanted but they completely repopulated the blood system of the mice,” said Catherine Verfaillie, director of the University’s Stem Cell Institute, in a statement released by the University of Minnesota. The cells did not differentiate into other cell types, such as liver or brain cells, nor did they form tumors in any animals, a common problem when using stem cells obtained from embryos.
Verfaillie was responsible for first identifying the existence of MAPCs in 2001. Difficulties in growing the cells and in reproducing the research results in other labs led to skepticism in the scientific community. Now, however, four different scientific publications support the current research, showing the results are consistent and replicable.
“These experiments point to potential precursors of blood forming stem cells in an unexpected population of cultured cells,” said Irving Weissman, who directs Stanford’s Institute for Stem Cell Biology and Regenerative Medicine.
“Scientists must now understand that mouse MAPCs can make normal blood, and we need to explore how they do it,” said Weissman, who was initially highly skeptical of the research proposal. “It is very important to note that MAPCs were not themselves radioprotective, thus they alone could not be used in patients in whom the bone marrow is totally eliminated due to radiation or chemotherapy, but it is still remarkable that they can give rise to blood cells.”
Further research is underway on animals more physically similar to humans, to prepare for potential treatments on people in the future. MAPCs have been isolated from bone marrow in humans, mice, rats and pigs.
In further developments, a team of researchers including participants from Spain, Belgium and the University of Minnesota showed the ability of the cells to differentiate into two types of cells that line the walls of blood vessels, known as endothelial cells. Scientists were able to make human MAPCs differentiate into cells for both arterial and secondary veins, in both lab tests and in mice.
“This work provides the first evidence that human MAPCs can be induced to differentiate into the different types of cells needed to form arteries,” Felipe Prosper, M.D., of Spain said in a study published in the journal Blood, November 2006. “This may suggest future clinical applications for MAPCs in diseases and conditions such as stroke and heart attack.”
Further research, published in the December 2006 issue of the Journal of Clinical Investigation, showed that the cells are capable of producing smooth muscle cells in the laboratory.
“While previous research has demonstrated that various types of stem cells can turn into cells tha t [sic] express the proteins consistent with smooth muscle, this is the first study that shows that the cells we generated have the same functional properties as smooth muscle, as well as express the same proteins,” said Jeffrey Ross, Ph.D., research associate at the Stem Cell Institute.
The research has potential for the future laboratory generation of working tissue, such as blood vessels for use in bypass surgery.
See full release published on Eurekalert:
https://www.eurekalert.org/pub_releases/2007-01/uom-uom011207.php
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