CNS stem cell transplantation: clinical and ethical perspectives.

Central nervous system disorders evoke special fear though their varied and unrelenting threats to memory, cognition, mobility, and every aspect of personal integrity and independence. Understandably, neurologic patients and their families become desperate for help, making fully free, informed consent problematic but not impossible. This desperation mandates our anticipatory attention to ethical questions related to any aggressive new therapy, including central nervous system grafting. In the United States, the right-to-life issue dominates ethical discussions on neural grafting. A variety of alternative tissue sources may permit technically suitable preparations, at least for some uses. If plentiful supplies of grafting cells can be made commercially, this should reduce problems related to allocating scarce resources, although financial and other scarcity barriers may still raise ethical problems. Many contemporary conceptions of selfhood depend on the identity and intactness of the mind and, by implication, the brain as substrate of mind. How much can we reweave the cerebral tapestry without creating a new self, a new identity? These philosophical questions will probably be approached pragmatically and incrementally, in the context of many other developments in human genetics and biomedicine. Our vision of the self will evolve amidst conflicting religious, ethical and pragmatic perspectives.

Models of repair mechanisms for future treatment modalities of Parkinson's disease.

Parkinson's disease is one of the most likely neurological disorders to be fully treatable by drugs and new therapeutic modalities. The age-dependent and multifactorial nature of its pathogenesis allows for many strategies of intervention and repair. Most data indicate that the selectively vulnerable dopaminergic neurons in the substantia nigra of patients that have developed Parkinson's disease can be modified by protective and reparative therapies. First, the oxidative stress, protein abnormalities, and cellular inclusions typically seen could be dealt with by anti-oxidants, trophic factors, and proteolytic enhancements. Secondly, if the delay of degeneration is not sufficient, then immature dopamine neurons can be placed in the parkinsonian brain by transplantation. Such neurons can be derived from stem cell sources or even stimulated to repair from endogenous stem cells. Novel molecular and cellular treatments provide new tools to prevent and alleviate Parkinson's disease.

[Patients' attitudes to xenotransplantation: "I'll do anything, I don't want to die!"]. / Patientröster om xenotransplantation: "jag skulle göra allt, för jag vill inte dö!"

Transplantation of neural tissue is an effective therapeutical approach in Parkinson's disease, but the method is constrained by the lack of suitable donor material. Embryonic neural tissue from pigs, xenografts, is considered as an alternative source of donor tissue. The attitudes towards neural tissue grafting in general and xenografts in particular were investigated by interviewing a group of patients with Parkinson's disease. The analysis revealed an ambivalence regarding xenografts. A pragmatic view, with priority placed on survival over ethical and other reservations, became apparent.

[Use of embryonal CNS tissue in Parkinson disease from the medical ethics viewpoint]. / Verwendung embryonalen ZNS-Gewebes bei Morbus Parkinson aus medizinethischer Sicht.

UNLABELLED: The transplant therapy discussed here contains ethical problems of some weight. In order to analyse them it is inevitable to distinguish between merely indirectly connected ethical problems and those that are central to this therapy. To the latter belong dilemmas on the individual as well as the social level, problems concerning the model of consent (on part of the pregnant woman) and the application of the 'therapeutic indication' (on part of the Parkinson patient). CONCLUSION: this transplant therapy is ethically highly questionable and should not be generally permitted; limited experiments for research may be necessary and ethically tolerable. More urgent is the pursuit of alternative therapeutic methods some of which are already being explored.

[Legal aspects of neurotransplantation]. / Rechtliche Aspekte der Neurotransplantation.

The use of human embryonic brain tissue for Transplantation has to be orientated in the need of protection for the embryo or fetus. Tissue derived from an abortion can only be used when a connection between the abortion and the application is excluded. The decision for an abortion should not be influenced by a possible usage of the tissue, as is stated in the guidelines of the german medical council for the use of fetal cells and tissue as well as in the guidelines from NECTAR. Criteria for death include brain death and cardiovascular arrest. If brain death can not be ascertained, one has to relay on the irreversible absence of spontaneous breathing and heart beat (after the exclusion of reversible factors like hypothermia or drugs). Authorization for the use of fetal tissue is given by the mother or the parents, their consent is a prerequisite for the use of fetal tissue.

[The legal and ethical aspects of nerve tissue transplantation]. / Pravovye i éticheskie aspekty neirotransplantatsii.

The authors have specified the following criteria for the withdrawal of embryonal tissue at their department: 1) only tissue from dead fetus is allowed to be used in neurotransplantation; 2) embryonal tissue is to be obtained after spontaneous abortions from volunteers or from women asking for artificial abortion; 3) the women should be informed about the curative purposes of embryonal tissue voluntary donorship and they must give a written consent; 4) decision on abortion should be separated from the use of embryonal tissue; 5) women should not know recipients; no payments should be made for tissue; 6) the donor is not permitted to impregnate in order to use embryos for research or clinical purposes; 7) sampling of BWR, HBsAG, anti-HIV, cytomegalovirus, herpes I and II is to be made for serologic examinations and that from the cervix for cultivation and sensitivity, as well as ultrasound verification of a germinal age is done in potential donors; 8) consent should be signed to embryonal brain transplantation by recipient or his legitimate deputy if the recipient is certifiable. The above criteria should protect both the donor and the recipient. The use of embryonal tissue cultures seems to be promising. In addition to legal and ethic problems, immunological problems and problems concerning the aseptic withdrawal of embryonal tissue are falling off.