You have all followed the news and debate about stem cells. As a reader of Living Longer and Loving It! you know that the Alliance for Aging Research is urging more research into cellular therapies in hopes of defeating Parkinson's and Alzheimer's, diabetes, cancer and other dread diseases.

In addition to embryonic stem cells, there are other cell-based technologies: fetal cells transplants and cloned stem cells created by a laboratory technique called "somatic cell nuclear transfer." This is when the genetic material is stripped out of a human egg cell and replaced with the nucleus of a donor cell that can come from any part of the body. This creates an embryo-like structure without fertilization that can produce stem cells genetically identical to the donor, and less likely to be rejected when transplanted to treat disease.

Despite the enormous potential of cell-based therapies, all of the research using fetal cells, embryonic stem cells and re-programmed or cloned cells has attracted controversy. The future of these studies is vulnerable to political pressures that could slow or even stop important medical research. Unfortunately, it's all too easy for the opponents of research to misinform and frighten the public about both the science and the ethics of creating new treatments by engineering human cells to act like medicines.

During a televised debate on stem cells, an anti-abortion activist who claimed fetal cell transplants have made Parkinson's patients worse confronted me. She argued that stem cell and fetal cell therapies are too dangerous so research should be stopped.

This person had taken a fragment of information from a news report about negative research results among a group of 40 Parkinson's patients. Thirty-four patients, all of whom had suffered from the disease for at least 14 years, had brain cells obtained from abortion clinics transplanted into the disease-affected areas of their brains.

In five of the patients the transplants worked so well, producing the chemical that is missing in Parkinson's disease, that they were able to stop all their anti-Parkinson drugs after one year. But in the second year of the study, those same five began experiencing involuntary muscle movements such as wriggling and writhing, apparently because the brain cell transplants worked too well. And unlike drugs, you can't easily lower the dose of a chemical that is delivered by an implanted cell.

Both the positive and negative results were published in the New England Journal of Medicine. But some media outlets pounced on the side effects as "proof" that the science had failed. In fact, the transplant study was extremely positive. Transplants survived in 85 percent of patients without immunosuppression (rejection) regardless of age. Younger transplant patients showed significant improvement in standardized measures of Parkinson's. Two years after transplant, 80 percent of all subjects were improved. For the five patients who had the adverse effects of excessive movement, their conditions since have been treated with drugs and with additional surgery including deep brain electrical implants in the brain.

Dr. Curt Freed of the University of Colorado Health Sciences Center, one of the leading researchers, told the Alliance all of the subjects would have been candidates for deep brain stimulation if they had not received the transplants, because conventional drug therapy had failed. Dr. Freed told us that four of the five patients whose side effects were described as "disastrous" and "tragic" by some reporters, now consider themselves much improved compared to before transplant.

Of course, that won't stop scare tactics from those who oppose all cellular therapies for reasons of their own from claiming that these are dangerous and ethically untenable experiments. Scientific progress seldom travels a straight upward path. To receive the benefits who all want from new discoveries in medicine and health, we must grant that research is, after all, a succession of successes and set-backs that gradually will shed light on the unknown.

If you agree with us on this, we hope you will continue following Living Longer & Loving It!, and pass this Alliance view on to your family and friends.