Stem cells: shedding light on the debate

Stem cells have great potential.ZoomZoom

Article published in the Courrier Laval on September 27, 2007.

Last month, the United States Congress voted in favor of a law to allow research on embryonic stem cells, but this law was countered the next day by the right of veto of the president, G. W. Bush. At the same time, in Europe, 50 billion euros are invested into adult and embryonic stem cell research. In these times when there are numerous debates on stem cells, it is useful to redefine them and to remember their uses.

Although the cloning of Dolly, the sheep, brought attention to stem cell research, it must be said that this research started long before. "We have been doing skin grafts on burn victims since 1985 at the LOEx" declares Lucie Germain, from the Laboratoire d'Organogenèse Expérimentale, of the Hôpital du Saint-Sacrement in Quebec City. These grafts come from skin biopsies taken from a burn victim, from which epidermal cells containing stem cells are cultured and then re-implanted into the patient. Similarly, transplantation of hematopoietic stem cells (capable of giving various blood cells) is practiced regularly after irradiation on patients treated for tumors. These are postnatal stem cells. There are also: totipotent, embryonic stem cells, capable of recreating an entire human being or pluripotent, embryonic stem cells that can create any kind of tissue in the human organism. In fact, the term stem cell defines a cell able to reproduce indefinitely and to give birth to differentiated cells. In effect, our body is composed of one hundred thousand billion cells from the same genetic pool, but these cells must specialize in order to perform very precise functions.

The therapeutic applications linked to embryonic stem cell research no longer need to be demonstrated. Just imagine if we could create organs or tissues at will. These are controversial methods, "a reduction of the human embryo to the state of an average," (declaration of Cardinal Jean-Pierre Ricard, June 29 of last year). In fact, at this time, the embryonic stem cells used come from unused eggs from in vitro fertilization. The problem of the lack of donors will certainly be resolved, but this is not the case for the problem of rejection. "Embryonic stem cells do not express the rejection (or histocompatibility) antigens, but when they differentiate, they start to express these antigens" specifies Lucie Germain. "We believe that the ideal cells will always be autologous", i.e., the patient's own cells, for which there is no rejection. At the moment, the research group is working on corneal tissue. "Presently, we could start from a small biopsy and have enough cells to cover the other eye". This research is preliminary but very encouraging. Since most organs have postnatal stem cells, we must now define their potential. This area of research would be a good alternative to research on embryonic stem cells, particularly since no side effects have been detected to date.