Courtesy Mike Jones
Embryonic stem (ES) cells are like blank cells that give rise to every type of cell and tissue in the body.
In Nov., 2007, scientists reprogrammed human skin into stem cells. That technique used cancer causing viruses which remained in the created stem cells.
Such genetic baggage posed safety concerns for potential therapies like cell transplants, and confounded work in the lab, as the introduced genes sometimes spurred mutations that interfered with the normal function of induced cells.
Now, by using a plasmid rather than a virus, James Thompson and Junying Yu have converted adult skin cells into pluripotent stems cells that are completely free of vector and transgene sequences.
The resulting cells, says Thomson, are remarkably similar to embryonic stem cells and show the same capacity to proliferate indefinitely in culture and diversify into all the cell types of the human body. Univ of Wisconsin News
This is a major advance toward safely reprogramming cells for clinical use. The new viral vector-free iPS cells will be available to researchers almost immediately through the International Stem Cell Bank at the WiCell Research Institute.
Research paper abstract in Science:
Human Induced Pluripotent Stem Cells Free of Vector and Transgene Sequences
Cut spinal cords, destroyed brain tissue, or damaged heart muscle can be repaired by injecting stem cells into the damaged area. Embryonic stem (ES) cells are like blank cells that give rise to every type of cell and tissue in the body. Using human embryos or unfertilized human eggs as a source of stem cells raised show-stopping opposition. Now stem cells have been produced from skin.
Two separate teams of researchers announced on Tuesday they had transformed ordinary skin cells into batches of cells that look and act like embryonic stem cells -- but without using cloning technology and without making embryos.
Both teams call the new cells induced pluripotent stem (iPS) cells and say they look and act like embryonic stem cells.
The research was published online Tuesday by two journals, Cell and Science. The Cell paper is from a team led by Dr. Shinya Yamanaka of Kyoto University; the team published by Science was led by Junying Yu, working in the lab of stem-cell pioneer James Thomson of the University of Wisconsin-Madison.
Thompson said the technique is so simple that "thousands of labs in the United States can do this, basically tomorrow." In contrast, the cloning approach is so complex and expensive that many scientists say it couldn't be used routinely to supply stem cells for therapy.