Stem cells are unspecialized cells that have the potential to mature into several cell types, such as neurons or cardiac cells. This has made several health and life scientists consider them as a tool for treatment for various types of diseases like cancers. The only catch is that stem cells that appear to have the best potential for treatment or therapy are from embryos (embryonic stem cells or ESCs), which raises ethical issues considering that harvesting ESCs will ultimately destroy the embryo.
However now scientists have found a way to reprogram adult cells into stem cells (induced pluripotent stem cells or iPSCs), avoiding the ethical issue altogether. While some scientists are doubtful whether iPSCs are as good as ESCs, a new study suggests that the two may be more equivalent than previously thought.
What was Done
There are several factors that contribute to the differences between iPSCs and ESCs. One is the source of the cells. The embryo used to derive an ESC is not genetically identical to the donor of the cell coaxed into an iPC. Another is the sex of the cells as gene activity varies between male and female. Thus, for this new study, scientists obtained two lines of male ESCs. These were allowed to mature and were eventually coaxed into iPSCs. Thus, genetically, these iPSCs match the ESCs. The gene activity of the iPSCs was more similar to the predecessor ESCs, suggesting that the source of the cells may in fact cause the disparities scientists previously noted. However the iPSCs still had differences from the parent ESCs, with 49 genes being pinpointed. Two of these genes, those involved in absorbing and digesting glucose,were analyzed. Even though both genes were less active in the iPSCs, the iPSCs were found to be just as efficient as the parent ESCs at absorbing and digesting glucose.
The ultimate test of a stem cell is its ability to produce different cell types. When this test was done on these two cell types, both were equally good at specializing into a variety of nervous system cells. They also ran a standard test that measures the cells’ ability to produce the three major cell lineages in the body and found no differences. The researchers concluded that both were “functionally indistinguishable.”