Stem cell interventions for treating Parkinson's disease

Stem Cell Research / Parkinson's

Since Barack Obama has become president, the field of stem cell research has been given new life. One of Obama's campaign pledges

was to allow deeper research -- including the use of federal research funds -- into the use of pluripotent stem cells in order to find solutions for some of the terrible diseases Americans suffer from. Among those medical problems is Parkinson Disease (PD). This paper reviews and delves into the literature in terms of the potential of stem cell interventions into Parkinson Disease (also called "Parkinson's Disease").

Who is the leading authority on stem cell research?

There is no one "leading authority" reflected in the literature; however there are renowned scientists that are considered pathfinders in this field. Dr. Diane S. Krause, Associate Professor of Laboratory Medicine and Associate Director of Stem Processing at Yale University is "…one of the discoverers of previously unknown innate sources of adult stem cells" (Gene Therapy, 2002). Krause is credited with contributing to the discovery of "recent revolutionary findings" that humans and other adult mammals process stem cells "…with the potential to differentiate into mature cells of the heart, liver, kidney, lungs, GI tract, skin, bone, muscle, cartilage, fat, endothelium and brain" (Gene Therapy).

Dr. Haifan Lin, who recently joined with Krause in the Yale Stem Cell Program, is also considered a preeminent scientists noted for his research on "…the most basic mechanisms of stem cell biology," according to Medicine at Yale. Lin has been at the forefront of the discovery that stem cells can "…both self-renew and produce daughter cells," having the ability to "differentiate into many distinct cell types" (Medicine At Yale). Lin established the stem cells from fruit flies as useful research tools, a first in the field.

The University of Melbourne has launched a major initiative to repair the brain cell damage vis-a-vis Parkinson's Disease, and the head of their team is "…internationally renowned stem cell expert Professor Martin Pera," according to the university's press release. Pera will be focused specifically on using stem cells to "rejuvenate and repair damaged and diseased cells…" in Parkinson's and others (Melbourne Newsroom). Pera is leading a team that is addressing the "progressive and permanent loss of a group of dopamine-producing brain cells," cells that should in normal conditions from the "essential pathway in the brain circuitry controlling movement" (Melbourne Newsroom). Those dopamine-producing brain cells must be replaced in order to relieve the Parkinson's patient of the tremors and other debilitating outcomes of PD.

What impact does stem cell research have on society?

Presently there has been no major breakthroughs vis-a-vis the use of stem cells in research that could find cures, therapies, or partial solutions for PD or other health-related issues. But the research is having an impact on public opinion, which is an important indicator for elected officials. In August, 2001, according to the Gallup Poll, 60% of respondents approved of President Bush's decision to cut off funding for stem cell research.

However in October 2004 when Bush announced that he would veto a bill from Congress that called for expanded federal funding for embryonic stem cell research, 64% responded that he should not veto that bill. And when Bush in fact did veto the legislation, 36% of those polled were "very upset" and 44% were "somewhat upset" that he vetoed the bill. In 2011, Gallop's poll showed a great deal of public support for medical research that involves "…using stem cells obtained from human embryos"; 62% of those polled said this research is "Morally acceptable" while 30% said it was "Morally wrong" (Gallup, 2011).

Meanwhile the most profound impact is yet to come, as therapies for medical problems like PD, and Alzheimer's, diabetes and other diseases are developed. That having been said, there is no doubt that the latest reports on the quality and quantity of stem cell research has given citizens -- especially those who suffer from PD, Alzheimer's, and other diseases, and the loved ones and family members of those sufferers -- a sense of realistic hope for therapies.

What does the current literature report about the importance of the issue?

One important component of the issue of stem cell research and Parkinson's is the significant need for an ethical approach that must be used in the research. In the peer-reviewed Journal of Law, Medicine & Ethics, the authors assert that within the genre of clinical trials there are critical ethical issues that need to be addressed and resolved. While patients and other advocates are pressing to see that stem cell science continue "moving expeditiously," the authors assert that "caution is appropriate" due to the "risk of adverse events" (Lo, et al., 2010, p. 257).

For example, the authors point to the incident where a boy who suffered from ataxia-telangiectasia, and who had received "repeated transplants of fetally-derived neural stem cells" had the misfortune during these medical procedures of developing "multiple tumors in his brain and spinal cord" that were brought into his system from donor cell lines used in the transplants (Lo, 257).

The specific ethical issues that Lo alludes to regarding Parkinson's research and other stem cell research (259) include the fact that there must be an "acceptable balance of benefits and risks, informed and voluntary consent" and the selection of subjects must be "equitable." Any findings must be "valid" and must be shared with others in the scientific community, and moreover, extreme safeguards must be in place due to the "…highly innovative nature of the interventions," because of the limited experience researchers have had in this genre, and because of the "permanent nature" of transplantation (Lo, 259).

Another ethical aspect to this research is referred to by Lo as "therapeutic misconception" (259). For example, in previous clinical research with cancer patients it was quite common for a cancer patient to expect that he/she "…will benefit personally from the trial, even though the primary purpose" of the clinical trials was "…to test safety rather than efficacy," Lo points out. The thought that a patient in a clinical trial expects to benefit personally is a misconception, and in some gene transfer clinical trials the researchers were giving out hope that there may be direct benefits to the participants (apparently this was part of the persuasive strategy to get the participants involved).

Lo (259) notes that the researchers' descriptions of potential "direct benefits" were "…vague, ambiguous, and indeterminate," which gave the misconceptions some reinforcement. This kind of behavior in a clinical environment is unethical. In terms of what is ethically proper in a clinical trial regarding stem cells and Parkinson's, Lo refers to the ethically acceptable design as an "add on" design: participants are assured of receiving the expected level of care in addition to "either the investigational agent or a placebo" (260).

In the case of PD, standard medications used (in addition to the investigational agent) include "L-dopa and dopa-decarboxylase inhibitors," which work to increase the levels of dopamine in the patient's brain. Another intervention vis-a-vis Parkinson's research involves the use of "deep rain stimulation (DBS)," which is known to be a good treatment for PD albeit DBS is relative new, Lo continues. Typically it would be ethical to employ DBS, however the clinical improvement of the PD patient -- following the introduction of DBS -- would be expected to be less than another participant in a control group that did not receive the DBS intervention (Lo, 260).

Why should this topic be studied further and deeper?

Parkinson's disease is a disorder that causes about half a million people in the United States to suffer severely. The disease hits sufferers with "…classical motor symptoms of bradykinesia, rigidity and tremor," according to Marios Politis and Olle Lindvall in the journal BMC Medicine. Moreover, those motor symptoms (though they are initially "subtle") build up to become significant, changing "cognition and mood," causing sleep disturbances and "autonomic dysfunction" (NINDS).

Clearly if there is an opportunity for science -- through the use of embryonic stem cells -- to find a therapy for Parkinson's, then more studies are justified. It was a setback when the previous presidential administration cut off the ability for legitimate science to use stem cells in research, but now that the door is open for this important research, all possible efforts should be made to continue until solutions are found for debilitating diseases such as Parkinson's.