Wednesday 1 October 2014

From Cloning Animals to Cloned Human Organs

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From Cloning Animals to Cloned Human Organs
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From Cloning Animals to Cloned Human Organs: The Social and Economic Benefits in Light of the Ethical Considerations

Shadi Farhangrazi

This past summer, audiences in movie theaters watched “The Island”, a fictional tale of a future world with cloned humans whose sole purpose was providing their organs for body parts. From the alarming and dramatic summer movies to the long debates on the floor of the US House of Representatives to the President threatening to veto a bill, we are in no doubt facing unprecedented times. What is happening is a great introduction to the events of the future. As history has shown, scientific and technological developments will move forward (if not in the US in other countries) at high speed, leaving society in the dust, to deal with the aftermath. There will be great economic potential as well as tremendous advances in medicine coupled with the societal and ethical challenges. As scientists take the path to research for new cures for many diseases, there will be cautionary notes and warnings. What is and will be required is open dialogue about the challenges and how we, as a society, will come to common ground and reap the benefits. We must achieve balance between scientific advancement and ethical issues.


From “Dolly” to “Therapeutic Cloning”

In 1997, the creation of the cloned sheep "Dolly" at the Rosalin Institute of Scotland not only started a new era in science and medicine but also sparked some of the most heated ethical debates of our time. “Cloning” [a general term used by scientists for common procedures or processes for duplicating biological materials] is also a word used most commonly in all the debates on stem cell research. The verb “to clone” means to make an identical or nearly identical copy. Every day in laboratories, scientists utilize various cloning procedures to produce clones of molecules, DNA and cells, i.e., making copies of the originals (DNA, molecules or cells). So, let's define and understand just what is meant by “cloning” in the case of Dolly and stem cell research.

The process of “asexual reproduction” which was used to create Dolly is different from “sexual reproduction” in which an egg and sperm join together. In sexual production, the resulting embryo will have half of its chromosomes from the mother (the female), and half from the father (the male). The process of cloning an organism requires two important components: an egg cell and the genetic material from a somatic cell (a cell from any part of the body). “Somatic Cell Nuclear Transfer (SCNT)” or “Nuclear Transplantation” is the term used for one type of cloning which creates an embryo through asexual production. The process of enucleation, which is the first step of this process, requires the removal of the nucleus containing the genetic material (the chromosomes) from the egg. The second step requires the transfer of the genetic material from the somatic cell (its nucleus) into the enucleated egg resulting in the production of an embryo which has all the chromosomes from the transferred nucleus (1, for a good reference). In a laboratory environment, the re-nucleated egg is placed in a dish with the essential nutrients and allowed to grow for a few days. The cloned embryo, at this point, would be placed into the uterus of a female host to grow and become a fetus. This is also the stage when stem cells could be isolated from the cloned embryo.

At the center of the discussions and public debates on “cloning” and “stem cell research” are the two terms “reproductive” and “therapeutic” cloning. In both reproductive and therapeutic cloning, the process of SCNT as described above is used to create an embryo. The way they differ is that reproductive cloning is a technology used to generate an animal (or human) that has the same nuclear DNA as another currently or previously existing animal. Dolly was created using reproductive cloning technology. Therapeutic cloning, also called "embryo cloning," uses exactly the same first steps in producing the human embryos for use in research but is done with the goal of harvesting stem cells that can be used to study human development and to treat disease. The embryo created asexually in the lab is taken at this stage and treated to produce cells that grow into a specific type (eg, heart, spinal cord, or pancreatic) of cell.

Many researchers hope that one day stem cells can be used to serve as replacement cells to treat heart disease, diabetes, Parkinson's disease, and other diseases. The promise of therapeutic cloning is that it offers the option of having the perfect match: an embryo cloned using a patient's cells could yield implantable cells or solid organs without risk of rejection or the need to take immunosuppressing drugs. The goal of research in the area of stem cell research is to use embryonic cells to create cells which could then potentially differentiate to become specific types of healthy cells and organs. Those cells or organs would in turn be transplanted into the patient to replace the diseased or damaged cells.

Reproductive cloning has been used to clone other animals since Dolly was cloned 1 . These include: mice, goats, pigs, cattle, rabbits, cats, dogs, and monkeys with varying degrees of success. In each case, as was done to produce Dolly, several clones were made and the cloned embryo was implanted in a female host (surrogate mother) and then brought to term. The process is extremely inefficient. In fact, it took the researchers over 250 tries to get to Dolly, thus highlighting a very important problem with reproductive cloning. In the best cases only less than 10 percent of clones could be implanted and then most of the implanted embryos do not survive the gestation period. At that point there is still the question of whether the clones which have survived are physiologically normal.

In addition to the significant and crucial problems related to the science of reproductive cloning, there are major ethical issues that are of concern. Almost all scientists and the public are not in favor of reproductive cloning of humans and agree that it is unethical to clone humans. However, it is “Therapeutic Cloning” which creates so much emotional reaction, and political and social opposition. It is the fact that the lines between reproductive cloning and therapeutic cloning have been blurred which makes it hard for many people to understand the issues and deal with the noisy public debate.

From the Halls of Congress to the Public

In the summer of 2001, after President Bush started his first term, he was faced with making a decision to outline his administration's position on “stem cell research.” It was only three years after the isolation of the first stem cells from embryonic cells, when the progress of science pushed the federal government to create new guidelines for funding research. President Clinton's administration was in fact the first administration to provide funding for stem cell research but both the science and the questions were too new to be addressed in broader terms and several guidelines had to be put into place.

In November 1998, the report of the isolation of human embryonic stem (ES) cells by Dr. James A. Thomson, from the University of Wisconsin , Madison , changed the path of science. Thomson's group derived ES cells from four-day old embryos (donated by couples through IVF clinics to science) which theoretically could differentiate into virtually any type of human cell (2). A few years prior to his discovery, Thomson had learned that his work was not eligible for federal funding from National Institutes of Health (NIH). Thomson and University of Wisconsin , therefore, had to seek private funding to set up a separate lab to work on human ES cells. Geron, a biotechnology company in Menlo Park , California , agreed to fund Dr. Thomson's research with certain rights to the patents and results of the research

It is important to understand the reason why the work was ineligible for federal funding, and the sequence of events that had led to that period in time. Dr. Thomson's work was not eligible for public funding because of a ban placed on NIH-funded human embryo research by Congress. However, in 1999, President Clinton asked the National Bioethics Advisory Commission (NBAC) to review the issues surrounding human ES cell research and NIH sought legal counsel from the Department of Health and Human Services (HHS) which at that time was led by Secretary Donna Shalala. HHS concluded that public funds could be used for ES cell research as long as the funds were not being used for derivation of the cells from human embryos. In addition, NBAC released its report in September 1999, concluding that the Federal government should fund ES cell research, specifically proposing that the Congress design an exception to its embryo research ban for the derivation of ES cells and soon after NIH started drafting guidelines for funding of ES cell research in the midst of all the controversy (2).

The guidelines allowed research on cells derived only from embryos leftover from fertility treatments and donated with the consent of the progenitors. In addition, if a fertility clinic were to profit from the sale of embryos used for stem cell derivation, research on those cells would not be allowed. NIH finally released the final guidelines in August 25, 2000 . During the next few months, NIH accepted new grant applications on ES cells, but the country was getting closer to the presidential elections, creating new uncertainties. However, as soon as President Bush came into office, he ordered a review of the guidelines and as a result, NIH cancelled the first scheduled meeting of its committee reviewing the grant applications which they had received based on previous guidelines.

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