Stem Cell Control
Stem Cell Control
A barrier to fully exploring the potential of embryonic stem cells, the much-discussed but little understood fons et origo of all other cells in the human body, is the rapid pace at which these cells differentiate.
Unlike most cells in our bodies, stem cells have the ability to "self-renew," or divide indefinitely. This means that, given the right set of biochemical circumstances, they can develop into any of the hundreds of adult tissue types -- from groups of pancreatic cells that could slow the advance of diabetes, to out-of-control cells that form malignant tumors.
Stem cells from embryos, charged with creating the vast array of mature cell varieties that could potentially become a fully formed person, show the greatest range of differentiation. Hence their value to scientists. But when grown in a laboratory, embryonic stem cells often differentiate spontaneously, leading to a mixed cell-type population. This makes it difficult for scientists to effectively observe and manage the tissue-formation process.
Researchers at MU say they have come up with a solution. By controlling the oxygen level of the cell's environment, they say, it is possible to mimic conditions found in the mammalian reproductive tract, thus helping to maintain the stem cells in an undifferentiated state.
R. Michael Roberts, Distinguished Curators' Professor of Animal Sciences and director of MU's Life Sciences Center, along with research assistant professor Toshihiko Ezashi and doctoral candidate Padmalaya Das, described their method for preventing stem cell differentiation in a paper published earlier this spring in the Proceedings of the National Academy of Sciences.
"We found that the trick to growing human embryonic stem cells is to maintain them under the same conditions under which embryos develop naturally," Roberts said. "In low-oxygen conditions, the cells differentiate much less rapidly. They still grow at the same rate, but the differentiation is much slower."
The insight should save much labor in the lab, Roberts says, by making it easier to grow stem cells with a specific outcome in mind. "This is just a way of manipulating these cells in a way to make them more useful," Roberts says. "The real value is in the area of tissue replacement."