Demystifying science and stem cells

This is the second of a two-part series. Read the first part online at tcextra.com.

Last week we discussed the several types of stem cells and asked whether embryonic stem cells can be replaced by adult stem cells. Do they have the same potential and can the adult forms answer for all of the therapeutic needs that we might want? That would solve a number of practical and ethical dilemmas.

The answer seems to be that the two kinds of stem cells are similar but not identical. The genes expressed in embryonic stem cells are not quite identical to those in adult stem cells, which seem to retain a memory of what they once were. The hope that the adult stem cells can substitute for the embryo derived ones does not seem justified, at least not yet.

Because the first adult embryonic stem cells were derived by a method that employs viruses, there is no prospect of using them in humans and no therapeutic human clinical trials are underway.

They are, however, very valuable for studying the causes of disease in the laboratory. The technology of adult stem cell research is moving fast and it may be that their limitations can be circumvented, but for the moment, from a purely clinical point of view, it is probably wise to work with both.

But what of that clinical test of embryonic stem cells in paralysis patients that we mentioned last week? I learned about this (as can you) by going to the website ClinicalTrials.gov. Search “spinal cord†or any other condition that you want to know about.

This site, maintained by the National Library of Medicine (your tax dollars again) lists all clinical trials in any country. There are 97,253 ongoing. There are 258 clinical trials in progress for spinal cord injuries. Most are palliative, concerned with easing pain or using mechanical devices.

The study we are interested in is No. 21 on the list and is run by the Geron Corporation. It will be conducted at academic medical centers on 10 recently paralyzed patients, the first of whom has been treated in Atlanta.

Neurosurgeons independent of Geron will inject 2 million embryonic stem cells into the sites of the injuries and with luck, the cells will grow and replace injured cells or perhaps they will nurture the injured spinal cord back to health. The patients will be assessed for side effects such as tumors or nerve pain.

In this Phase 1 trial there are no controls — that is, patients who do not receive the stem cells. If there is clinical improvement, that would be excellent, but with so few patients and no control patients (so perhaps any improvement is not due to the stem cells), any conclusions would be tentative. If the Phase I trial looks hopeful, a Phase II with more patients and controls will occur to ask whether the injection of stem cells really helps.

Finally, a much larger Phase III trial will take place and only after its successful completion will the therapeutic use of these stem cells be possible. This process takes a long time (years), there will be setbacks, and it will be expensive. Other trials will tackle a host of other diseases.

Could embryonic stem cell research occur faster?  In 2001, President Bush decreed that only existing stem cell lines could be used and no new ones could be prepared with public money. Private money or state money could be used.

This ruling had the effect of blocking the participation of academic labs in the development of human stem cells for therapy. These institutions — Columbia, UConn and Yale among them — have Ph.D. programs with smart students who do not mind working 12 hours a day if they think their work can help a patient or increase our basic knowledge.

Unless the institutions that train them could get private money and build entirely separate labs, they could not participate, although the students could work on adult stem cells.

The Obama administration relaxed the Bush-era rules and the National Institutes of Health began funding embryonic stem cell research to the tune of tens of millions of dollars. Their scientific review committees are relatively objective (in my experience) and believe that we need embryonic and adult stem cell research.

But in September 2010, Chief Judge Royce Lamberth of the U.S. District Court for the District of Columbia ruled that the work violated the will of Congress and banned it overnight, causing consternation among scientists and researchers. Embryonic stem cells need to be tended every few days, and so unless action was taken, they would die and research (and careers) would be lost.

On Sept. 10, the Justice Department obtained a stay of Judge Lamberth’s order. The matter remains to be adjudicated. The ethical, political and judicial issues are complicated and stir passions. Scientists are no better at moral decisions than other people, but the biology of stem cells is a good place to start a discussion.

Richard Kessin, Ph.D., is professor of pathology and cell biology at Columbia University. He and his wife, Galene, live in Norfolk.

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