HELENA VETORAZZOThe evidence that research with embryonic progenitor cells (stem cells) has achieved over the last few months is a result of progress and of controversy. The progress attained in this area indicates that research into them is going to produce countless practical applications for medicine and biology, but at the same time it is generating a lively controversy in the terrain of ethics, leading governments, parliaments and religious leaders to opine. It has to be said that many of the discussions are based on speculations that are distant from current scientific reality, edging on the field of science fiction, while the multiplicity of stem cells in the organism helps to confuse the issue.
The ethical reservations concern only one category of these cells: totipotent embryonic cells, derived from the inner mass of the blastocyst, obtained from the ovum fertilized in the laboratory or from fetal tissues obtained by premature termination of a pregnancy. The similarity between transferring a nucleus into a somatic cell represents an alternative method for producing an embryonic stem cell, and the similarity of this approach to the initial steps of cloning mammals has contributed towards increasing the confusion.
The possible applications of these cells in medicine include the regeneration of tissues (like the myocardium after a heart attack, the pancreas in diabetics, the muscular tissue of those suffering from muscular dystrophy, and even the nervous tissue, until a short time ago thought as being impossible to regenerate). These lineages may also serve for testing medicines and to understand the complex mechanisms involved in human development and the factors that control the formation of specialized cells, with important effects for cancer research.
Another beneficial consequence of these studies is that they encourage research into adult stem cells, multipotent cells present into several human tissues, the most well known and explored of which are hematopoietic cells. In parallel, the blood from the umbilical cord may prove to be a source for less mature progenitor cells, as it has already happened in the case of hematopoietic lineage.
The scientific community has a central role to keep up research in this area, and to encourage dialogue with society, to avert fears and to help define the limits for interference. We ought to encourage basic and applied research into the use of progenitor cells from different sources, and, at the same time, to spur off a debate based on scientific research and on the interest of society, to allow researchers to participate in the great progress that will be taking place in this area in the immediate future. In this regard, the ethical debate on experimenting with embryonic cells very often seems to be misplaced.
What, for example, is the destination given to the frozen supernumerary embryos, obtained from laboratory fertilization, kept in fertility clinics, which will no longer be used for implantation and for the development of fetuses? The ethical debate should be concentrated on their production. If society and medical organizations regard it as ethical to produce them for reproduction (and they are produced in the thousands) and they are not capable of finding a useful end for them, their use for medical purposes and for research does not seem to be indefensible.
Marco Antonio Zago teaches at the Faculty of Medicine of USP in Ribeirão Preto and is the coordinator of the Cellular Therapy Center Cepid
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