All the ABC’s of bioethics have returned currently to the issue of embryo research. But first of all, let’s remind what’s the definition of a stem cell.

There are two kinds of stem cells: the totipotent stem cell which has the ability to differentiate into all types of cells, and the pluripotent stem cell which has a capability to give several types of cells. Apparently, the interest of researchers is focused on embryonic stem cells, the only problem is that they may involve the destruction of the embryo.

The researchers are interested by embryonic stem cells, which are extracted from embryos aged 5 to 7 days, i.e., those called pluripotent because they can differentiate into several types of human cell (blood, liver, heart, muscle, etc. ). For Annelise Bennaceur, a french hematologist and director of an INSERM unit on stem cell models:

Knowing how does an embryo form is essential for the understanding of human genetic diseases that form in early stages of development.

In addition, the aim of stem cell research is to treat serious disorders. With embryonic stem cells, the idea is to control their differentiation by forcing them to evolve into the type of cell we want. But there are other sources of stem cells such as the adult stem cell, the cord blood stem cell and the induced pluripotent cells, which are adult cells reprogrammed to treat a specific pathology. Some types of cells have already proven their effectiveness: nearly 10 000 cord blood transplants were carried out in the world to treat blood diseases.

For instance, Nicolas Forraz, a researcher at the Institute for Research on Cord Blood Cell therapy (Lyon Saint-Priest / France) along with Professor Colin McGuckin, at the University of Newcastle, were able to differentiate cord blood stem cells in precursors of nerve cells, liver and pancreas. Furthermore, they identified pluripotent stem cells in the cord blood. Quoting Nicolas Forraz:

I feel sorry that most of the french public funds are invested in embryonic stem cell research. It would take at least a rebalancing of the grants.

Finally, there is another significant problem that those attempting to use embryonic stem cells for therapeutic purposes have to confront, it’s called immune rejection. Because embryonic stem cells will not ordinarily have been derived from the specific patient to be treated, there is a risk that they will be rejected by that patient’s immune system.

Scientists have proposed several different ways of avoiding this difficulty. These include using research cloning (somatic cell nuclear transfer) procedures to generate human embryonic stem cells that are genetically identical to those of the person receiving the transplant, genetically engineering the embryonic stem cells to express certain antigens of the recipient that would counter any possible immune reaction, or developing ”universal” donor stem cell lines that could be used in many different patients. However, each of these methods has its drawbacks.