The Ethics of Fetal Tissue Transplants

Abstract

The Ethics of Fetal Tissue Transplants Heretofore, damage to the brain or spinal cord, whether from injury or disease, has been considered irreversible. There is no satisfactory cure for Parkinson's or Alzheimer's disease, for paraplegia resulting from spinal cord injury, for certain forms of epilepsy, or for a host of other less common but equally grave neurologic disorders. This situation may soon change. Over the last ten years, animal experiments have demonstrated that transplantation of appropriate fetal brain tissue to an impaired adult brain can in certain cases restore normal function. Human fetal brain tissue recently was used in transplants for patients with Parkinson's disease in Mexico and Sweden, and similar procedures are planned or underway in China, Canada and elsewhere. Future uses of fetal tissue may not be restricted to neurosurgery but might include transplanting of fetal pancreas to treat diabetes mellitus or fetal liver for certain blood and metabolic disorders. The prospect of therapeutic use of human fetal tissue has aroused strong emotions. Objections have been raised on several grounds: * The requisite killing and dissection of the fetus both are an abuse to the developing human being and brutalize those who perform them. Further, the therapeutic use of fetal tissue will encourage abortion, may motivate conception with the express intent to abort, and might even lead to the sale of fetuses and fetal material. * Collection of fetal tissue in a medically useful form exposes the mother to unnecessary risk, while transplantation of such tissue exposes the recipient to unacceptable risk. * The medical use of human fetal tissue has unacceptable social consequences. * The legal safeguards necessary to overcome these objections are either undesirable or unenforceable. Such objections raise important issues for the most immediate practical application of fetal tissue, the transplantation of human fetal dopamine-secreting neurons to the brains of patients with medically unresponsive Parkinson's disease. Scientific Grounds Parkinson's disease is a devastating neurologic disorder that occurs when neurons degenerate in the region of the midbrain called the substantia nigra. Normally, fibers from these cells secrete the chemical dopamine in forebrain regions important for regulating movement. In the absence of normal dopamine secretion, the patient suffers from a variety of impairments including rigidity, difficulty initiating movements, and tremor. The underlying causes of the disease are unknown and there is currently no cure. Existing drug treatments inevitably lead to unacceptable side effects, and as the disease itself progresses the patient becomes unable to carry out the essential activities of daily life. Animal experiments over the last decade have demonstrated that fetal dopaminergic neurons can be grafted to the brain, restoring normal movement to rats and monkeys with experimentally induced Parkinson's disease. Similar grafts of tissue from adult adrenal glands, which also produce dopamine have been shown to have beneficial effects in animal experiments. Such a procedure has been performed in at least one hundred patients with Parkinson's disease in Mexico, China, Sweden, and the United States. While it would be premature to draw definitive conclusions about the therapeutic value of this procedure, there appear to be no significant adverse effects. Nonetheless, based on animal experiments, it is likely that grafts of fetal human dopamine-secreting neurons will be substantially more effective than adrenal grafts. Procedures for transplanting human fetal neurons are under development in a number of laboratories, and at least five operations have been performed in Mexico City, Stockholm, and Birmingham, England. [1] Numerous factors influence the success of neuronal transplantation to the brain. …