A new report out says that all federally approved lines of embryonic stem cells are contaminated with a non-human sialic acid molecule. New research now suggests those lines may not prove useful as therapeutic agents.
The sialic acid, Neu5Gc, is found on the surface of some animal cells, e.g., pigs, dogs, and mice, and human immune systems recognize the molecule as foreign and automatically attack Neu5Gc-bearing cells. Inspection in the laboratory proved that all U.S. embryonic stem cell lines currently used in research have picked up Neu5Gc during the culturing process
While the federally approved lines remain useful for in vitro or animal studies in the lab, it points out a reason to look at non-embryonic [adult] stem cell sources, such as umbilical cord blood, bone marrow, fat cells, other types, which can be harvested and transplanted whole, without the need for culturing. Researchers are also working to develope new methods of culturing stem cells without animal-cell contamination.
The full details of the study are published in the Jan. 23 issue of Nature Medicine after being outlined to a panel of stem cell experts at the National Academies of Science in October. More here.
