Ethical Issues in Cellular and Molecular Medicine and Tissue Engineering

All theory, dear friend, is gray, but the golden tree of life springs ever green. Motto “omnis cellula e(x) cellula” (“Every cell is derived only from a preexisting cell”). The objective of tissue engineering is to create or recreate living body parts or organs that will fully integrate with the recipient's body. The advent of tissue engineering as a new field of research with a high potential towards the clinical care of patients from bench to bedside has involved numerous different scientists in various fields of cellular and molecular medicine, material research, engineering, physics, chemistry, computational research and allied disciplines [1-5]. Due to a potentially enormous impact on the health of our society – that is as a whole continuously becoming older – tissue-engineered solutions to circumvent natural degenerative processes have become of great interest. They may aid to maintain a high quality of life in the elderly. This issue has been widely acknowledged, but has created numerous debates also. Many of the techniques applied in research and in practical applications of nowadays tissue engineering approaches [3] with direct or indirect relation to the care of human beings seem to be straight forward and do not offer a sufficient potential for ethical debates [6-8]. Nevertheless, innovative medical research and new technologies always raise ethical and policy concerns. In biomedical research, these issues include the ethical conduct of basic and clinical research as well as the equitable distribution of new therapies [7]. While questions of intellectual property have been widely published in this context, there is limited literature on ethics in cellular and molecular medicine and for the field of tissue engineering [6, 9, 10]. With respect to the ethics of tissue engineering, Derksen and Horstman [11] have suggested that one can roughly distinguish two perspectives. On the one hand, this technology could be considered morally good because tissue engineering is ‘copying nature’. On the other hand, tissue engineering could be considered morally dangerous because it defies nature: bodies constructed in the laboratory are seen as unnatural. The tremendous public attraction that the implantation of cultured chondrocytes in the form of a human ear cartilage (which was implanted under the skin of a nude mouse and that was eventually called auriculosaurus [1]) gained rapidly all over the world is a vivid testimony to the perception of people when confronted with such spectacular and obvious research efforts. Based on the discussion of the engineering of heart valves, authors have proposed that the ethics of tissue engineering should be framed not in terms of ‘natural’ or ‘unnatural’ but in terms of ‘good embodied life’ and ‘lived integrity’[11]. While research with stem cells from the very beginning has evoked many controversial debates worldwide not only within the recent years (especially when those cells are derived from embryos), there is comparatively little public debate on ethical issues in cellular and molecular research, when it is not directly correlated to clinical applications. A survey of the literature reveals that the term ‘ethics' in cellular and molecular medicine is not covered in a database such as PubMed, while the term ethics and cellular medicine offers 608 papers published between 1967 and 2008. Decades ago, early papers such as Vogels report on: ‘Can we count on the possibility of manipulation in the field of human genetics? May we and are we permitted to breed people?’[12] or Hirschhorn's comment on ‘re-doing man’[13] were discussing the principle question and the fear of any manipulation of the human genetic information at all. At that time even reproductive medicine was in its childhood as Ramsey's considerations on the medical ethics of in vitro fertilization show [14, 15]. However, it has to be remembered that at the same time the first successful clinical heart transplantation was made public in 1967. The public confusion of transplanting organs from one human being into another – especially the human heart – was considerable. It is widely recognized that despite better knowing about the function of the brain even nowadays feelings are literally more associated with the heart than the brain. The famous quotation of Antoine De Saint Exupery ‘It is only with the heart that one can see rightly; what is essential is invisible to the eye’ may serve as a vivid example of this phenomenon. Looking back into this field of scientific publication nowadays such questions seem to have been more or less answered over the time, although it is clear that they cannot be definitely solved for every opinion and for all times. For instance, the field of in vitro fertilization to overcome human infertility has become a clinical routine worldwide and is currently being financed by many social security systems in developed countries. Genetic manipulation of the human genome seems nothing spectacular today. The human genome has been decoded in many aspects and DNA fingerprint tests are popular practice in many fields of our daily life. This demonstrates that parallel to any progress in cellular and molecular research the debates also are subject to changing perceptions over time. Issues that have been extremely controversial decades ago have become less critical in the public perception today and new challenges arise with the ever-progressing efforts in cellular and molecular research. Ethically of course the acclimatization to habits that have become daily practice does not mean that they are ethically unobjectionable by themselves. However, an ethical reflection should not be addicted to fashions and should keep in thinking critically. Nevertheless, due to the translational character of cellular and molecular medicine [16-19] many critical questions can arise from this field of research that may pose ethical problems. It is always difficult to estimate the true benefits to individuals and to society that are gained by the introduction of new drugs or medical technologies. As an example it may be recognized that the introduction of antibiotics and vaccines has enormously increased our life spans and improved the health conditions of people all over the world. Nevertheless still major illnesses such as cancer, diabetes mellitus, Alzheimer's disease, heart disease are ongoing and challenging conditions, which desire continuous research on a cellular and molecular basis. Research in human developmental biology has led to the discovery of human stem cells that have been described for many decades and that have been subject to multiple investigations. Human stem cells are precursor cells that can give rise to multiple tissue types, including embryonic stem (ES) cells, embryonic germ (EG) cells, and adult stem cells. The discovery of techniques for the in vitro culture of stem cells has provided unprecedented opportunities for studying and understanding more about human biology [20]. In human beings, transplants of haematopoietic stem cells following chemotherapeutic treatments for cancer, for example, have been routinely administered for many years now. It has been proposed by scientific communities that persons considering donating their excess embryos for research purposes should be afforded the highest standards of protection for the informed consent and voluntariness of their decision [21]. But if the human embryo is seen as a human being – and there are a lot of reasons to do this – there remains the question why medicine does not prevent supernumary embryos at all from the ethicist's standpoint. In view of the moral concerns surrounding the uses of embryonic and foetal tissue voiced by a segment of the American population, it has been proposed by the AAAS (American Association for the Advancement of Science, Science magazine) that strengthening federally and privately funded research into alternative sources and/or methods for the derivation of stem cells, including further initiatives on adult stem cells, should be encouraged [21]. According to their statements human stem cell research can be conducted in a fully ethical manner, but it is considered to be true that the extraction of embryonic stem cells from the inner mass of blastocysts raises ethical questions for all those who consider the intentional loss of embryonic life by intentional means to be morally wrong. Also, the derivation of embryonic germ cells from the gonadal tissue of aborted foetuses is problematic for those who oppose abortion [21]. From an ethical point of view there are enough objections at the moment to the process of deriving stem cells to consider AAAS recommending against its public funding. In contrast, adult stem cell research is more broadly acceptable to the population. Generally there seems to be no discussion in the media about the so-called adult stem cells, since the potential benefit appears to be very high and the utilization of the patient's own cells poses no serious ethical conflict. Although it is impossible to predict the potential outcome, momentarily worldwide many experiments carried out that aim towards the determination of the mechanisms underlying the conversion of a single, cell into the different cells the and organs and of the human body. A high potential of has been for this field of research, but is still not or the widely and policy the potential of stem cells to human whole human remains a subject of ongoing public For the of from stem cell research, we to to the literature that is and is from that stem cells could potentially into cells of and it is that these cells in their experiments the transplantation of foetal tissue into the of could that the that stem cell therapies could treatments for many human may be a although this has not been definitely today. 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