Are the benefits of stem cells being oversold?

Abstract

Stem cell news dominates the front page nearly every day. The situation is now complicated by the announcement of some scientist-entrepreneurs of their plans to undertake human cloning to help infertile couples, despite clear opposition from scientists and lawmakers. The issues of stem cell research and human cloning at first seem to be unrelated, but in fact are more complex. Take the case of Advanced Cell Technology, a biotech company whose chief executive officer, Michael D. West, has publicly stated that his company would like to create human clones for stem cell research. The idea is to take a nucleus from the patient's skin cell, transfer it to an egg whose nucleus has been removed, and allow the egg to form a blastocyst in a petri dish. This blastocyst contains 200–250 stem cells (each a sort of “blank slate” cell) that can be coaxed to develop into many different cells in the body. Use of this type of “designer” stem cell will most likely avoid immunological rejection, a fate that often awaits other transplanted cells. This approach makes medical sense, but would require the procedures involved in human cloning. Most scientists understand the difference between therapeutic human cloning and reproductive human cloning, but will the public distinguish between these subtleties? The sad reality is that the latest hoopla and furor generated by Drs. Severino Antinori, Panayiotis Michael Zavos, and Brigitte Boisselier, who are hell-bent on human cloning, will undoubtedly influence lawmakers to propose even more stringent legislation. I have another concern — the outlandish promises being made to promote stem cell research. In their desire to prevent a ban on embryonic stem cell research, scientists, advocates, and news media are touting the great medical benefits of this technology for humankind. It is not unusual to read that stem cells can be used to recreate an entire new pancreas for a diabetic patient, generate a “brand new” healthy heart to replace the damaged old heart, make a new liver to replace the nonfunctional liver, repair spinal cord injuries, create dopaminergic neurons for curing Parkinson's or even Alzheimer's, and on and on, stopping just short of generating a new brain. Proponents of adult stem cell research insist that hematopoeitic stem cells can be transdifferentiated into muscle cells, neurons, hepatocytes, and so on, even though the efficiency of this process is so low as to be impractical. Patients read these news items attributed to scientists and are excited at the prospect of a cure. It is true that adult and embryonic stem cells have tremendous potential to alleviate human suffering, but we are running the risk of overhyping the promise. Even the most ardent practitioners of stem cell therapies do not expect stem cells to be converted into a pulsating, functional, three-dimensional heart any time soon. In our zeal to undertake research on the potential benefits of stem cells, we must be careful not to give false hope. It is cruel to the patient and, in the long run, detrimental to the public's support of science. I see some parallels between stem cell hype and the early days of gene therapy, when curing genetic diseases, ameliorating cancer, slowing down the progression of degenerative diseases, and other claims often made the headlines stem cells are making now. I still believe in the potential of gene therapy: the twenty-first century is already known as the “century of the gene” and there is great promise of alleviating suffering from disease and improving human health. But new and highly experimental technologies have inherent risks and uncertainties. Scientists must find a balance between excitement and eagerness, problem and promises, and hopes and hypes. The reality is that the timeline of promises kept is unpredictable, but the reaction to unfulfilled expectations is predictable.