New Embryonic Stem Cell Lines Avoid Animal Products

Researchers at Stanford University School of Medicine derived new human embryonic stem cell lines using minimal animal products. Although numerous groups have derived stem cell lines, most were generated in the presence of animal serum and animal-derived feeder cells. These animal products are a concern because they may cause the stem cells to produce an immune response when transplanted into humans and may induce biological changes especially to the genome. In this study, the team characterized six lines that were derived with minimal use of animal products.  The researchers verified that the lines behave like normal ES cells in their ability to both self-renew and differentiate to the major cell types.  These lines may be useful for future studies that help move the field toward clinical-grade cell therapy.

Stem Cells and Development: June 17, 2008
CIRM funding: Renee Reijo Pera (RC1-00137)

Related Information: Stanford Stem Cell Biology and  Regenerative Medicine Institute, Pera lab page

Fly Stem Cells Create their Home

Researchers at the Salk Institute of Biological Studies discovered that stem cells in the testes of fruit flies are able to generate their own support cells. This work in flies could help guide researchers hoping to understand the environment surrounding resident populations of human stem cells - called the niche. The niche is difficult to study in humans but is an area of great interest because any therapy based on transplanting stem cells into a tissue will require those cells to be paced in a niche where they will thrive. This work raises the possibility that some transplanted stem cells may be able to produce their own niche.

Nature: July 20, 2008
CIRM funding: Justin Voog (T1-00003)

Related Information: Salk press release, Salk Institute for Biological Studies

Aging Muscles Inhibit Stem Cells, Prevent Repair

Researchers at UC, Berkeley identified a signaling molecule that interferes with the ability of older skeletal muscle to regenerate. After injury, adult skeletal muscle regenerates by activating muscle stem cells that fuse with the existing muscle cells to repair the damage. This ability to regenerate diminishes with age, not because of a decline in the number of resident stem cells, but because stem cells in the older muscle don’t respond when damage occurs. It turns out that older muscles release molecules that actively inhibit the resident stem cells. In this study, the team identified one of those molecules and showed that interfering with that molecule’s function restores the ability of muscle in older mice to regenerate after injury. This research illustrates the potential for recruiting adult resident stem cells in tissue repair.

Nature: June 15, 2008.
CIRM funding: Morgan Carlson (T1-00007)

Related Information: Press release, Berkeley Stem Cell Center