Adult Stem Cell Technologies
Stem cells can now be harvested from embryos, umbilical cord blood and tissue, amniotic fluid, bone marrow, adipose tissue, peripheral circulation, and even brain tissue and stem cell niches in the eye and the liver. Once thought extremely rare in the adult body, stem cells are now found in more and more places each year with increasing potential for developing specific stem cell therapies that address diseases affecting specific tissue types.
Induced pluripotent stem cells (iPSCs) are a significant achievement in stem cell research which, again, shows the ways in which science can find a way around legislation and funding issues. At first believed to be capable only of differentiating into the type of tissue in which they were originally found, adult stem cells have now been able to be ‘regressed’ back to an embryo-like state where pluripotency is possible and the adult stem cells are unlimited in the types of cell they can form. This stem cell technology uses skin stem cells, adipose-derived stem cells, or other adult stem cell source, and inserts four specific genes from a tissue cell for the purposes of extending the repertoire of the adult stem cell as it differentiates. There is no embryo created in this technique and, thus, no ethical concern in this regard.
Consistency in Stem Cell Pluripotency
A persistent problem for those working with adult stem cells is the difficulty encountered when trying to make adult stem cells pluripotent consistently. Researchers investigating the role of the Tet protein in stem cell function discovered last year that the particular protein Tet1 is key to maintaining the pluripotency of stem cells with ramifications for creating pluripotent stem cells from adult tissues. New research has uncovered the same protein’s surprising role in the mechanisms behind stem cell differentiation and cancer development. Biochemist Yi Zhang and his team at UNC are investigating the ‘sixth base’ of DNA, 5-hydroxymethylcytosine, which results from the protein as it figures in leukaemia and other forms of cancer. The research may be helpful in developing ways to prevent unwanted differentiation from implanted stem cells as well as furthering progress towards an effective strategy for turning multipotent adult stem cells into pluripotent stem cells more consistently.
The use of adult stem cells evades the moral debate to some extent although concerns do exist here too over stem cell technologies and their potential applications. The insertion of human neural stem cells into the brains of mice in research on neurodegenerative diseases has been highlighted as a concern for many. This is not due to animal rights issues, but instead, the development of human brain tissue in animals, thus blurring the line between species in an ‘unnatural’ fashion. Research concentrating on bioengineering human organs and tissues in animals for transplantation has also raised concerns, meaning that the rapid progression of stem cell technologies has been flagged by some as needing more stringent regulation to take into account those things which have become possible in recent years which were not even conceived of when original stem cell legislation was outlined in many countries.
Continue Reading –> Embryonic Stem Cell Technologies
