Wednesday, November 15, 2006

Stem Cell Clarity

From a molecular biologist. His research is in an area of cell biology related to cancer. As such, he is following the findings and debate surrounding stem cell research very closely.

First let's define what stem cells are. There are two major kinds, adult and embryonic.

A stem cell can be roughly defined as a cell that can divide, such that one or both of the resulting daughter cells can go on to become a progenitor (or founder) for a large number of other cells that have a specific functions (brain cells, muscle, bone, etc). In adult tissue the stem cell remains a stem cell, providing new progenitor cells throughout its lifetime, but only dividing slowly when new cells are needed. These are adult stem cells. In the embryo, a stem cell could continue dividing rapidly, producing not only progenitor cells of a particular cell type, but also other stem cells.

As adults, we are likely to carry stem cells in all major tissues of our body, including brain. Much effort has taken place over the last decade in trying to identify and isolate these cells (without compromising the function of the tissue). For example, in skin researchers have shown that the stem cells are located in a small bulge structure that is part of every hair follicle. Thus, if we can isolate enough of these from for example a burn victim, we could theoretically resupply the necessary skin cells in the laboratory using the stem cells as the progenitors. These cells could then be grafted onto the wounded areas, without all the graft-host rejection problems when donor skin is used. One can now imagine similar strategies for replacing damaged brain tissue (Parkinsons, Alzheimers, accidents, etc), lung tissue, liver, kidney, muscle, and so forth.

Why take stem cells from embryos if we can do the above? That is more a practical problem. Right now skin and bone marrow are amongst the few adult tissues where identifying and isolating the stem cells can be done efficiently. And even in these cases it will be some years before these techniques are widely applied clinically. Embryonic stem cells on the other hand are usually easier to propagate in culture (they divide much more rapidly), and often can be directed towards a particular cell type. The holy grail in stem cell research would be to isolate cells that can be directed to become any cell type, using the right culture conditions.

Advances in stem cell technology are coming every day, whether made in the US or abroad. In fact, with the current federal funding restrictions, we can be assured that most of the major advances will not be in America, unless funded by private sources, as is taking place in California and Massachusetts (not coincidently blue states). We need to continue stem cell research if we are ever to advance beyond the need to isolate stem cells from embryos.

Those whose power is based on clinging to tradition and maintaining the status quo (religious leaders, conservative politicians) are once again standing in the way of scientific advancement. And as always, they stand on the wrong side of history.

The children and grandchildren of people like George Bush and Pat Robertson (and the Pope, in a non-literal sense) will live longer and healthier lives, not because of anything they've done, but in spite of their ignorance.


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