Britain urged to expand embryo studies.

Abstract

BIOETHICS Biologists in Britain who want to use human stem cells to develop new medical therapies say the chances for government support are looking brighter. They're encouraged by an opinion issued in London by a senior advisory panel urging the U.K. government to enact a new law to ban “reproductive cloning” of humans while permitting a limited type of cloning for research on new methods of treating disease. The recommendations, written by a joint working group of the two agencies that regulate the use of human reproductive technology in the country—the Human Genetics Advisory Commission (HGAC) and the Human Fertilisation and Embryology Authority (HFEA)–are expected to carry substantial weight in the U.K. The report could also become a model for other countries, say U.S. researchers, including developmental geneticist John Gearhart of Johns Hopkins University in Baltimore, who has cultivated human stem cells from fetal tissue. The joint HGAC and HFEA working group, headed by the Reverend Dr. John Polkinghorne—an Anglican minister and mathematical physicist—began reviewing U.K. policy last January at a time when the press was full of speculation that humans might soon be cloned. The working group drew up a summary of key issues and sought public comment. On cloning for reproductive purposes, the outcome was “conclusive,” says legal philosopher Sir Colin Campbell, HGAC's chair and vice chancellor of the University of Nottingham: “86% of the people who commented supported a ban on human reproductive cloning.” The working group also endorsed a total ban. But a fraction of respondents also favored limited research that involves DNA transfer into oocytes, the process that produced the sheep Dolly. Besides offering a way to copy an organism, cloning might enable researchers to transfer DNA from a defective to a healthy embryo, and it might also allow them to create new tissue for transplants. The working group, says Campbell, supports research in these two areas. In the first, aimed at studying diseases rooted in the mitochondria—the cells' energy-producing organelles—DNA might be transferred from a cell with deficient mitochondria into a healthy oocyte, creating an embryo that could develop into a healthy child. The goal of the second line of research would be to clone a patient's DNA in stem cells derived from an embryo and coax those cells to develop into tissues that would be accepted by the patient's immune system. “The eventual clinical use of such [transplantation] procedures,” the report notes, “would be to provide immunologically compatible tissues for the treatment of degenerative diseases of, for example, the heart, liver, kidneys, and cerebral tissue, or repair damage to skin or bone.” The potential medical value, it adds, is “enormous.” The report recommends that research licenses be granted for these areas of research. “This seems like a very positive signal that may open the door to research” on new methods of human cell therapies, says developmental biologist Austin Smith of Edinburgh University in Scotland. Existing U.K. guidelines allow researchers to obtain a license for research on human embryos up to the 14th day of development, but only for narrow applications such as improving fertilization methods. (At present, Britain has licensed 24 such projects at 18 centers.) Under the proposed new rules, however, these early embryos could be used for broader purposes, such as developing stem cells that can grow into a full range of specialized tissues—one of Smith's goals. The HGAC-HFEA report lets agencies know that they should now give serious consideration to grant requests in these areas, says Smith. In the past, he says, restrictive legal policies have made it difficult to obtain funding even for research that would lay the groundwork for stem cell experiments. The new approach would “allow the science to move forward,” Smith says. The decision on whether to accept these recommendations, however, rests with the health ministry and the HFEA, which have not announced what they plan to do.