Monkeys get human fetal cells.

Monkeys Get Human Fetal Cells

Scientists performing the first reported U.S. transplants of human fetal brain cells into the brains of monkeys found good graft survival after 70 days, according to findings published this week. The experiments sought to prove the feasibility of therapeutic fetal-cell transplants into humans suffering from neurological disorders such as Parkinson's disease. They are the first performed anywhere showing nerve cells from human fetal cadavers can be isolated, frozen, tested for purity and safety, then thawed and implanted successfully into primate brains.

While allaying many of the remaining doubts about the safety and survivability of such transplants, the report may also fan the flames of controversy over researchers' growing use of fetal tissue from induced abortions. The United States has placed a moratorium on all government-sponsored studies of human fetal-tissue transplants pending the results of a policy review by the National Institutes of Health (see story, p.296). The latest transplants, reported by D. Eugene Redmond Jr., and his colleagues at the Yale University School of Medicine, along with researchers at the University of Rochester (N.Y.) School of Medicine, were supported by private funding.

"This is an important advance, as it demonstrates the viability of cryopreserved, cadaverous fetal tissue for use in implants," says Irwin J. Kopin of the Bethesda, Md., National Institute of Neurological and Communicative Disorders and Stroke. A proposal by Kopin and others to perform similar research in humans this past spring had prompted the government moratorium.

Researchers in Sweden, Mexico and elsewhere have already transplanted human fetal neural tissue into the brains of patients with Parkinson's disease, but graft survival in those recipients remains uncertain. Some researchers have criticized those experiments because they involved immediate transplantation of the fetal tissue without thorough testing for bacterial or viral contamination. In Redmond's study, tissue was frozen in liquid nitrogen while scientists checked for contaminants.

Seventy days after transplantation, the grafted cells had formed dense networks of maturing nerve cells (see cover photo), the U.S. researchers say. Two of three grafts showed signs they were producing dopamine, the neurochemical that is in short supply in parkinsonian brains. Similar transplants into monkeys with Parkinson's-like symptoms -- already performed by the team but as yet unreported -- should indicate whether the procedure has therapeutic potential.

In an unusually lengthy footnote to their research, which appears in the Nov. 4 SCIENCE, the researchers spell out the ethical guidelines they followed in obtaining and using the fetal tissue from consenting women who had independently elected to have first-trimester abortions.