Although there have been many breakthrough studies into stem cell therapies, there have also unfortunately been some disappointments as well. One such disappointment has been the aim to provide a large amount of embryonic stem cells from hybrids.
To successfully use hybrid stem cells, there are genes that are vital to stem cell development. These genes have to be turned on but thus far, researchers have been unable to accomplish this task.
At present, embryonic stem cells are only attainable through discarded embryos left from in vitro fertilisation procedures. They are highly controversial and the search for alternate stem cell sources is a major one, namely to avoid the controversy. While there have also been stories of success in ‘reprogramming’ adult stem cells into an embryonic-like state, there are still problems with this source.
Embryonic stem cells are ones that have the ability to form any specialised cell in the body while other kinds of stem cells – although still valuable – don’t have quite the same potential.
One hope was that by taking the nucleus out of an animal egg and then using the nucleus from a cell in an adult human, we could essentially gain an unlimited supply of embryonic stem cells. The hope had been that the egg’s DNA would cause the nucleus to go back to an embryronic state and allow us to extract stem cells that would contain the DNA of the adult who donated the original cells. This would also avoid the risk of immunological rejection in the adult donor, which is another benefit of this therapy if it worked.
Looking at Genes
In experiments, however, it has unfortunately been shown that genes do not behave as they should in the hybrids. They did not mimic the expression of those genes in normal embryos from humans. Another problem was that the hybrids didn’t develop properly to the important stage known as the blastocyst. Here, there is a cluster of approximately a hundred cells, which is vital for obtaining stem cells.
In the hybrids, development seemed to halt early on, generally around the eight to sixteen cell stage. The alerts that are necessary to trigger continued cell development just didn’t seem to be there and the nucleus wasn’t totally reprogrammed as it should have been.
Other scientists, however, are still hopeful that some of these vital genes may eventually be turned on. Scientists in Asia were apparently able to create cybrids from human skin cells and they reported that the blastocyst stage was indeed reached and the critical genes were also turned on. The downside was that the number of cybrids that were able to reach this stage were sparse in number.
Despite the disappointments of some stem cell research, the future does still look very exciting for finding stem cell treatments that can improve and save lives. Most of the research in this area has been promising and shows that we are making progress into this important area. The setbacks only mean that we must continue to fund ethical stem cell research to search for safe, successful ways to treat disease.