Use of Embryonic Stem Cells to Treat Severe Eye Diseases

BACKGROUND

The use of stem cells in regenerative medicine has major therapeutic potential. Recent clinical trials using cells derived from human stem cells are showing encouraging results, although these should be assessed with the necessary caution.

DISCUSSION

Some media have reported the results of these trials without due care, perhaps creating expectations that do not match the reality of the facts. This paper describes some of the recent advances in the use of human stem cells, particularly those made in the area of ophthalmology, and more specifically, in Stargardt's disease and age-related macular degeneration (AMD). We also present promising studies with induced pluripotent stem cells (iPS), aimed at obtaining retinal pigmented epithelium and light-sensitive retinal rods in the aforementioned ocular diseases, with encouraging preclinical and clinical results.

CONCLUSIONS

From a medical point of view, we must not forget that the transplanted retinal epithelium cells may cause tumours, since they have been obtained from Embryonic Stem cells, and may trigger immune rejection problems since they are heterologous. These considerations attest to the ethical uncertainty of the results of these clinical trials, but above all, it must be stressed that whenever Embryonic Stem cells are used, a human embryo must be destroyed to obtain them, which of course has objective ethical difficulties.

An ethically justified framework for clinical investigation to benefit pregnant and fetal patients

Research to improve the health of pregnant and fetal patients presents ethical challenges to clinical investigators, institutional review boards, funding agencies, and data safety and monitoring boards. The Common Rule sets out requirements that such research must satisfy but no ethical framework to guide their application. We provide such an ethical framework, based on the ethical concept of the fetus as a patient. We offer criteria for innovation and for Phase I and II and then for Phase III clinical trials to improve the health of pregnant patients and of fetal patients and also criteria to responsibly manage the transition from investigation to clinical practice. Basing ethical criteria for research involving pregnant women on the ethical concept of the fetus as a patient insulates the proposed ethical framework and therefore research on pregnant women from the divisive and politicized concepts and discourses of personhood, fetal rights, and unborn child.

Washington insider

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Human embryo and early fetus research

Studies of human embryos and fetuses have highlighted developmental differences between humans and model organisms. In addition to describing the normal biology of our own species, a justification in itself, studies of early human development have aided identification of candidate disease genes mapped by positional cloning strategies, understanding pathophysiology, where human disorders are not faithfully reproduced by models in other species, and, more recently, potential therapies based on human embryonic stem and embryonic germ cells. In this article, we review these applications. We also discuss when and how to study human embryo and early fetuses and some of the regulations of this research.

Bioethics and the future of humanity

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Draft National Institutes of Health guidelines for research involving human pluripotent stem cells (December 1999)

The National Institutes of Health (NIH) is requesting public comment on a document entitled "Draft National Institutes of Health guidelines for research involving human pluripotent stem cells (December 1999)". The purpose of these draft guidelines is to recommend procedures to help ensure that NIH-funded research in this area is conducted in an ethical and legal manner. The NIH will not fund research using human pluripotent stem cells until final guidelines are published in the Federal Register and an oversight process is in place.

Ethics of research and the pregnant patient

In this chapter, we address ethical issues in research involving fetuses and pregnant women, with particular attention to the emerging issue of gene-transfer research. Ethical analyses and arguments are based on the concept of the fetus as a patient. The implications of this concept for the ethics of fetal research are identified. The discussion of gene-transfer research extends those implications to address issues concerning informed consent, assessment of potential fetal and neonatal morbidity in study design, prenatal diagnosis after gene transfer, selection criteria based on abortion preference, science by press conference, germline risks, and public oversight.

[Dutch Institute for Health Care Improvement's standard code of practice entitled, "Donation of fetal tissue"]

The Dutch Law on Foetal Tissue (Wet Foetaal Weefsel) sets out conditions and regulations concerning the donation, storage and permissibility of use of foetal tissue. Each institution where foetal tissue becomes available has to formulate an in-house code of conduct describing how the law will be applied within that institution. A committee, including abortion physicians and gynaecologists, has formulated a number of rules of conduct within the standard code of conduct under the auspices of the Kwaliteitsinstituut voor de Gezondheidszorg CBO [Dutch Institute for Healthcare Improvement]. Complying with this standard code ensures that the law is upheld. In clinical practice, one may deviate from this standard code in case of solid reasons only. Generally, all women can be asked to donate foetal tissue. A basic prerequisite for the inclusion of non-Dutch women is that oral and written communication is possible. The committee considers the age of 16 as a minimum threshold and mental incompetence as an exclusion criterion. Much attention should be paid to providing the women with information and to requesting permission. The basic principle is that the decision to terminate a pregnancy should be strictly separated from the decision to donate foetal tissue. As a general rule, foetal tissue should be stored anonymously. Adjustment of the abortion method in view of the intended scientific research is not permitted.

[Comments on the Dutch Institute for Health Care Improvement's standard code of practice entitled, "Donation of fetal tissue"]

Under the auspices of the Kwaliteitsinstituut voor de Gezondheidszorg CBO [Dutch Institute for Healthcare Improvement] a standard code of practice was developed as a template for local institutional codes to implement the Law on Foetal Tissue. It is a useful model code, but arguments should have been outlined more explicitly, notably in instances where the code adopts a somewhat stricter position than the Law. The following remarks pertain to the model code: 1. It may be argued that the inclusion or exclusion of 12-15-year-old pregnant girls should be relative to the privacy-related sensitivity of the use of foetal tissue. 2. Transplantation requires additional tests for the safety of the recipient, including testing for HIV/AIDS. A pregnant woman's permission for such testing should not be taken for granted. 3. The abortion technique may be modified in view of the subsequent use of foetal tissue if the woman consents to the modification, with the prerequisites that the modification does not harm the woman and that any potential sensation of pain by the foetus must be minimised.

Maternal-fetal research and human research protections policy

It may be that the current system of formal definitions, ethical theories, and voluntary professional guidelines to protect patients from unwittingly becoming subjects of research is inadequate to meet the challenge of surgical innovation. Important questions, such as when surgical innovation becomes research involving human subjects or how to distinguish between variations on an existing technique and true innovations, are key. These questions also apply to MFS as an innovative surgical therapy. Now that MFS has been recognized as experimental and formal clinical trials will be conducted, it is important to ensure adequate protection of the pregnant women and fetuses involved as human research subjects. This issue is even more pertinent in light of the new regulations regarding fetuses as research subjects. Those responsible for reviewing study protocols will have to be especially careful when examining the new version of DHHS regulations as they apply to future studies in the field of MFS.

Embryonic stem cell research: one small step for science or one giant leap back for mankind?

At the forefront of modern debate over the ethical use of biotechnology is embryonic stem cell research. In this poignant analysis of its legitimacy, the author examines the history of this research in light of the United States' policy favoring the protection of human beings over scientific progress. Stem cells, which can divide in culture to create specialized cells in the human body, possess significant potential for curing disease, particularly when taken from human embryos. However, as evidenced by the research atrocities committed under the Nazi regime, the benefits of human research do not come without a cost to humanity. Recognizing this, the later trial of these scientists produced the Nuremberg Code, a set of natural law principles guiding future research on humans that continues to influence health policy decisions. Drawing on this background, the author first considers the appropriate legal status for a human embryo. Biologically, the characteristics of a human embryo place it between human tissue and a constitutional person. Judicially, the answer is even less clear. The author analyzes case law in the context of abortion and in vitro fertilization, as well as classifications by the common law, state legislation, and the National Bioethics Advisory Commission, to conclude that a human embryo should be subject to the same legal and ethical restrictions as any other "human subject." Accordingly, the author argues that embryonic stem cell research violates the ethical standards and purposes of the Nuremberg Code and should be banned by federal legislation. Such a prohibition will fulfill the societal policy choice of protecting potential life and vulnerable human subjects.

Lengthening the stem: allowing federally funded researchers to derive human pluripotent stem cells from embryos

Recent developments in fetal tissue research and stem cell research have led to dramatic breakthroughs in the search for cures for Parkinson's disease, Alzheimer's disease, diabetes, and a host of neurological disorders. Because this research involves fetal tissue and stem cells from human embryos, many complicated ethical and legal implications surround it. This Note explores the history of fetal tissue research and stem cell research, examines the surrounding ethical and legal issues, looks at the current state of federal law, and concludes that Congress should allow federally funded researchers to derive stem cells from discarded human embryos obtained from in vitro fertilization clinics.