Scientists confirm reprogrammed adult stem cells are identical to embryonic stem cells.
Adam Rifkin stashed this in Stem Cells
Researchers from the Vavilov Institute of General Genetics, Research Institute of Physical Chemical Medicine and Moscow Institute of Physics and Technology (MIPT) have concluded that reprogramming does not create differences between reprogrammed and embryonic stem cells. The results have been published in the journal Cell Cycle.
Stem cells are specialized, undifferentiated cells that can divide and have the remarkable potential to develop into many different cell types in the body during early life and growth. In addition, they serve as a sort of internal repair system in many tissues, dividing essentially without limit to replenish other cells. When a stem cell divides, each new cell has the potential either to remain a stem cell or become another a more specialized cell type, such as a muscle cell, a red blood cell, or a brain cell (Fig 1). Scientists distinguish several types of stem cells. Stem cells that can potentially produce any cell in the body are called pluripotent stem cells. There are no pluripotent stem cells in an adult body; they are found naturally in early embryos.
There are two ways to get pluripotent stem cells. The first is to extract them from the excess embryos produced during the in vitro fertilization procedure. But this practice is still controversial technically and ethically because it does destroy an embryo which could have been implanted. This is why researchers came up with the second way to get pluripotent stem cells – reprogramming adult cells.
The process of "turning on" genes that are active in a stem cell and "turning off" genes that are responsible for cell specialization is called reprogramming. This technology was pioneered by Shinya Yamanaka, who showed that the introduction of four specific proteins that are essential during early embryonic development could be used to convert adult cells into pluripotent cells. He was awarded the 2012 Nobel Prize along with Sir John Gurdon "for the discovery that mature cells can be reprogrammed to become pluripotent."(Fig.2).
Thanks to their unique regenerative abilities, stem cells offer potential for treating any disease. For example, there have been cases of transplanting retinal pigment epithelium and spine cells from stem cells. Another experiment showed that stem cells were able to regenerate teeth in mice. Reprogramming holds great potential for new medical applications, because reprogrammed pluripotent stem cells (or induced pluripotent stem cells) can be made from a patient's own cells instead of using pluripotent cells from embryos.
However, the extent of the similarity between induced pluripotent stem cells and human embryonic stem cells is still unclear. Recent studies highlighted significant differences between these two types of stem cells, although only a limited number of cell lines of different origins were analyzed.
As far as I know, and I'm just a graduate with a bachelor's in biochemistry so it's not a whole lot, this article pretty much just spells out what we already know. And that the title is pretty misleading. The article states that the transcriptomes and the genomes are identical. While that's true that does not mean that the cells themselves are identical. Much of the differences between induced pluripotent stem cells (iPSCs) and embryonic stem cells (ESCs) lie in the nature of their chromatin. As cells differentiate, they acquire methylation in their DNA, as well as various histone modifications to condense and expand relative sections of DNA, all affecting the probability a gene will be expressed.
This article doesn't argue that. It just states that the genes present are the same, which they are--this is really nothing novel. The key component to the future of iPSCs is getting rid of these methylation markers and post-translational markers on histones to really bring back the full stemmyness of these cells.
That being said, this technology represents a great potential to future clinical treatments and would overcome a lot of the problems, morally and scientifically, of using embryonic stem cells.