Stem cell research and the cloning wars.

• Author: Korobkin, Russell

In the 1976 novel The Boys from Brazil, (1) the infamous Nazi concentration camp doctor, Josef Mengele, who disappeared after World War II, never to be found, has created ninety-four clones of Adolph Hitler. The children, sent to live with German families around the globe, are being raised in circumstances that Mengele has chosen to mimic Hitler's upbringing. Now that the clones have reached the age at which Hitler's father died, Mengele sets out to have each of the ninety-four stepfathers murdered. The stoic Mengele thinks nothing of the bloodshed, of course. It is just one more necessary step in his plan to breed a new "Fuehrer" who will lead a reconstructed "Fourth Reich." In the movie version, an icy Gregory Peck portrays Mengele, while Laurence Olivier plays the Nazi hunter, a character based loosely on Simon Wiesenthal, who successfully foils the plot. (2)

There would seem to be a great distance between a man called "the Angel of Death" bent on recreating history's most evil man and academic scientists trying to create new kinds of disease treatments that will not set off immune system reactions in patients. The scientific distance, however, is not so great. The consequence of this similarity, unfortunately, is the potential enactment of legislation that could severely undermine the medical potential of stem cell research, which offers hope for finding cures for debilitating diseases and injuries. This article explains how a revolutionary biomedical technology became entangled in the cloning wars and why Congress should not permit it to become a casualty.

Part I explains the scientific basis for the unfortunate rhetorical linkage between cloning human beings and potentially revolutionary medical research. Part II describes the state-level legislation that prohibits both and the congressional bill that would do the same. Part III describes and responds to the policy arguments for enacting a cloning ban that would extend to the use of cloning technology in stem cell research rather than stop at prohibiting cloning for reproductive purposes. This Part concludes that, although there are plausible arguments for the broader ban, the fears that they seek to address are not sufficient to justify the costs to medical research. Part IV evaluates three sets of constitutional problems raised by a broad congressional cloning ban: the breadth of federal regulatory power under the Commerce Clause, individual rights to reproductive liberty, and individual rights to pursue medical treatment. This Part concludes that none of these concerns would likely be sufficient for federal courts to strike down a cloning ban as unconstitutional, but that they are sufficiently serious to provide an independent basis for Congress to reject the ban.

1. STEM CELL RESEARCH AND CLONING

   1. THE POTENTIAL OF STEM CELL RESEARCH

      Each human cell contains forty-six chromosomes, half inherited from the mother and half from the father, that together contain the person's entire genome--that is, every one of his or her genes. According to the findings of the Human Genome Project, the genome of each human consists of about 25,000 genes.(3) Different types of cells have different characteristics and different functions: skin cells, blood cells, bone cells, and brain cells, for example. In order to be able to serve such different functions, different genes are activated, or "expressed," in different types of cells, while the remaining genes in any particular type of cell lie dormant. Through "gene expression," the cell creates particular proteins that, working together with proteins created by other cells, build and maintain the organism and enable it to function. (4)

      When a specialized cell is created, its function is decided and is fixed. In the lingo of cell biology, such a specialized cell is "fully differentiated." The genes that are expressed will remain expressed, while the others will lie dormant. A stem cell, in contrast, is one that is not fully differentiated. It can divide into two identical copies of itself, but it also can divide into one copy of itself and one different, more specialized cell, with a different gene expression pattern. (5)

      The least differentiated of stem cells, embryonic stem cells (ESCs), are found in very early stage embryos, called blastocysts. (6) ESCs have the potential to develop into all of the types of tissues found in the human body. (7) More differentiated stem cells, often collectively called adult stem cells (ASCs), are found in fetuses and persons. (8) ASCs can develop into one or more kinds of specialized cells, usually within the same tissue type--for example, hematopoietic stem cells have the ability to develop into nine types of blood cells (9)--but lack the flexibility of ESCs. (10) Most scientists believe that ESCs have greater scientific potential because they are easier to harvest, are more stable, and can replicate for longer periods of time than ASCs, (11) and because many types of specialized cells cannot be developed from any known ASCs. (12) ESC research is far more controversial, however, and is mostly ineligible for federal research funding at this time (13) because the destruction of the blastocyst is a necessary side effect of harvesting ESCs, given technology currently in use.(14)

      Stem cell research potentially could lead to cures for a wide range of diseases with a genetic component (and also treatments for injuries that damage or destroy cell populations, such as paralysis) in three different ways. First, by studying the ways that stem cells differentiate and create specialized cells, researchers hope to better understand the causes and development of a range of diseases that result from abnormal cell division or differentiation or from cell injury or death. (15) Second, if scientists can prompt stem cells to differentiate and develop in ways that mimic the progression of diseases, researchers can test the efficacy and toxicity of pharmaceuticals and other medical treatments on the stem cells. (16)

      Third, and most significant, is the potential of stem cells to directly cure diseases and repair injuries. In theory, stem cells, prompted to differentiate into healthy specialized cells, can be used to replace diseased or dead cells. In other words, medical science can harness the body's natural healing powers to cure disease rather than relying on blunt, external force that fights against the body's biology, such as surgery, chemicals, or radiation. One approach is to inject stem cells into the diseased or damaged area of the body and allow them to regenerate healthy cells inside the body. (17) Another is to prompt stem cells to actually grow replacement cells or tissues outside of the diseased body and then surgically rep, lace the diseased tissues with the specially constructed replacements. (18) For example, heart cells destroyed by a heart attack could be grown with stem cells and used to patch the organ.

   2. THE ROLE OF SOMATIC CELL NUCLEAR TRANSFER (SCNT) IN STEM CELL RESEARCH

      If and when researchers learn how to use stem cells therapeutically to replace or repair dead or damaged cells, they likely will still face the problem of the patient's body rejecting the presence of foreign cells. (19) This has always been a problem in the context of bone marrow and organ transplants, skin grafts, and the like that attempt to place tissue from one individual into the body of another individual. Proteins on the surfaces of donor cells called human leukocyte antigens (HLA) alert the immune system of the recipient to the presence of foreign cells. (20) Because foreign cells could be harmful viruses or bacteria, the immune system of the host responds by attacking (and killing) the cells of the donor. (21) The donor tissue can also sense that the cells of the host are foreign to it, and attack those cells. This side effect of transplants is known as "graft versus host" disease. (22)

      In modern practice, physicians attempt to match transplant donors and recipients with similar HLA profiles, which reduces the rejection problem but does not solve it entirely. (23) Recipients of organ transplants also must take immunosuppressive drugs, which produce side effects. (24) If stem cell treatments could be developed using only cells that match those of the patient however, the tissues will be a perfect HLA match, and the problem of rejection could be avoided without the need for high doses of dangerous drugs.

      Scientists hope to one day create individualized, rejection-proof stem cell therapies through a process called somatic cell nuclear transfer (SCNT). The process requires one human egg cell and one adult "somatic" cell, which could theoretically originate from any part of a donor's body. The nucleus of the egg cell is removed and replaced with the nucleus of the somatic cell, resulting in an egg that is genetically virtually identical to the somatic cell donor. (25) The trick, at this point, is to stimulate the egg in a way that convinces the genes in the transplanted nucleus to express as if the cell were a zygote rather than an adult cell. If this feat is accomplished, the egg will begin the long process of cell division that could lead eventually to the birth of an organism. (26) After several days, scientists would harvest ESCs from the developing embryo exactly as they would harvest ESCs from an embryo created through the normal process of fertilizing an egg cell with a sperm cell, and use those ESCs to develop therapeutically useful cells. (27) But because these cells would be virtually identical to those of the donor, the problem of immune system rejection should, in theory, be solved. (28)

      In 2004, South Korean scientist Woo Suk Hwang announced that he had used the SCNT process to create a human ESC line. (29) The following year, he claimed to have improved his laboratory's efficiency and created eleven lines. (30) Months later, however, rumors began to circulate that Hwang's data and...