What's Wrong with Human/Nonhuman Chimera Research?

Debates on humanization of human-animal brain chimeras - are we putting the cart before the horses?

Research on human-animal chimeras have elicited alarms and prompted debates. Those involving the generation of chimeric brains, in which human brain cells become anatomically and functionally intertwined with their animal counterparts in varying ratios, either via xenografts or embryonic co-development, have been considered the most problematic. The moral issues stem from a potential for "humanization" of the animal brain, as well as speculative changes to the host animals' consciousness or sentience, with consequential alteration in the animal hosts' moral status. However, critical background knowledge appears to be missing to resolve these debates. Firstly, there is no consensus on animal sentience vis-à-vis that of humans, and no established methodology that would allow a wholesome and objective assessment of changes in animal sentience resulting from the introduction of human brain cells. Knowledge in interspecies comparative neuropsychology that could allow effective demarcation of a state of "humanization" is also lacking. Secondly, moral status as a philosophical construct has no scientific and objective points of reference. Either changes in sentience or humanization effects would remain unclear unless there are some neuroscientific research grounding. For a bioethical stance based on moral status of human-animal brain chimera to make meaningful contributions to regulatory policies, it might first need to be adequately informed by, and with its arguments constructed, in a manner that are factually in line with the science. In may be prudent for approved research projects involving the generation of human-animal brain chimera to have a mandatory component of assessing plausible changes in sentience.

ISSCR guidelines for the transfer of human pluripotent stem cells and their direct derivatives into animal hosts

The newly revised 2021 ISSCR Guidelines for Stem Cell Research and Clinical Translation includes scientific and ethical guidance for the transfer of human pluripotent stem cells and their direct derivatives into animal models. In this white paper, the ISSCR subcommittee that drafted these guidelines for research involving the use of nonhuman embryos and postnatal animals explains and summarizes their recommendations.

Mapping the Ethical Issues of Brain Organoid Research and Application

In 2008, researchers created human three-dimensional neural tissue - known as the pioneering work of "brain organoids." In recent years, some researchers have transplanted human brain organoids into animal brains for applicational purposes. With these experiments have come many ethical concerns. It is thus an urgent task to clarify what is ethically permissible and impermissible in brain organoid research. This paper seeks (1) to sort out the ethical issues related to brain organoid research and application and (2) to propose future directions for additional ethical consideration and policy debates in the field. Toward (1), this paper first outlines the current state of brain organoid research, and then briefly responds to previously raised related ethical concerns. Looking next at anticipated scientific developments in brain organoid research, we will discuss (i) ethical issues related to in vitro brain organoids, (ii) ethical issues raised when brain organoids form complexes or have relationships with other entities, and (iii) ethical issues of research ethics and governance. Finally, in pursuit of (2), we propose research policies that are mindful of the ethics of brain organoid research and application and also suggest the need for an international framework for research and application of brain organoids.

[Comments on Relationships with Artificial Emotional Intelligence - from "Here and Now" to "There and Then"]

The structure of relationships in the past, the present and the future is shaped by the idea of humanism. Based on this construct, the article illuminates various aspects and configurations of humanism on a timeline from "here and now" to "there and then". The current reality of care goes hand in hand with an emotional alienation of relationships. Advances in technology and reductionist neurobiological ideas can make it difficult to look at a person's mental illness as a whole. Any (communication) technology that has been developed in the past or will be developed in the future will sooner or later find its way into psychiatry and psychotherapy and change relationships. Transhumanism runs the risk that people will become alienated from each other and their species. Neural networks are algorithms that work regardless of the hardware used, be it based on organic carbon units such as humans or non-organic silicon units such as the computer/cyborg. There will be different ways to achieve super intelligence. Intelligence is a "must" and consciousness is a "can". If there is a change from a homocentric to a data-centered world view and the power of humans is transferred to the algorithms, humans could lose their economic value and the humanistic goals of health and happiness would be lost.

The new Japanese regulation on human/non-human chimeras: should we worry?

In March 2019 Japan modified its norms regarding research with human/non-human chimeras. The amended rules allow the creation of chimeras with human brain cells, and the subsequent transfer of the resulting creature to an uterus, where it can develop for more than 14 days, eventually until term. At this moment, the real consequences of this new regulation in actual research are still uncertain. However, many concerning issues have already been identified. This paper will start by addressing traditional topics involving this practice: the use of non-human animals in research, the use of human stem cells in scientific experimentation and the creation of human/non-human chimeras. Subsequently, it will analyze the new concerning issues brought on by the 2019 amendment: the use of human brain cells, the transfer of the chimera to an uterus and its development for more than 14 days, and the possibility of using animals which present close similarities with humans. In the end, the paper will conclude that in spite of the legal and ethical hazards that this new regulation might carry, it should be allowed under strict scrutiny.

Integrating Philosophy of Science into Research on Ethical, Legal and Social Issues in the Life Sciences

This paper argues that research on normative issues in the life sciences will benefit from a tighter integration of philosophy of science. We examine research on ethical, legal and social issues in the life sciences (“ELSI”) and discuss three illustrative examples of normative issues that arise in different areas of the life sciences. These examples show that important normative questions are highly dependent on epistemic issues which so far have not been addressed sufficiently in ELSI, RRI and related areas of research. Accordingly, we argue for the integration of research on the epistemic aspects of the relevant areas of science into ELSI research to provide a better basis for addressing normative questions.

Human-Animal Chimeras: The Moral Insignificance of Uniquely Human Capacities

Human-animal chimeras-creatures composed of a mix of animal and human cells-have come to play an important role in biomedical research, and they raise ethical questions. This article focuses on one particularly difficult set of questions-those related to the moral status of human-animal chimeras with brains that are partly or wholly composed of human cells. Given the uncertain effects of human-animal chimera research on chimeric animals' cognition, it would be prudent to ensure we do not overlook or underestimate their moral status. However, to assess moral status, we first need to determine what kinds of capacities are morally relevant. The standard view holds that it matters, morally, if chimeric animals develop uniquely human cognitive capacities. I argue that this view is mistaken, highlighting three problems with it: that we can think of examples of uniquely human cognitive capacities that are not morally significant, that we can think of examples of morally significant cognitive capacities that are not uniquely human, and that evidence that some cognitive capacity is shared with nonhuman animals does not undermine claims that this capacity is morally significant. We need a better framework for thinking about the moral status of part-human beings.

Ethical arguments concerning human-animal chimera research: a systematic review

Background

The burgeoning field of biomedical research involving the mixture of human and animal materials has attracted significant ethical controversy. Due to the many dimensions of potential ethical conflict involved in this type of research, and the wide variety of research projects under discussion, it is difficult to obtain an overview of the ethical debate. This paper attempts to remedy this by providing a systematic review of ethical reasons in academic publications on human-animal chimera research.

Methods

We conducted a systematic review of the ethical literature concerning human-animal chimeras based on the research question: “What ethical reasons have been given for or against conducting human-animal chimera research, and how have these reasons been treated in the ongoing debate?” Our search extends until the end of the year 2017, including MEDLINE, Embase, PhilPapers and EthxWeb databases, restricted to peer-reviewed journal publications in English. Papers containing ethical reasons were analyzed, and the reasons were coded according to whether they were endorsed, mentioned or rejected.

Results

Four hundred thirty-one articles were retrieved by our search, and 88 were ultimately included and analyzed. Within these articles, we found 464 passages containing reasons for and against conducting human-animal chimera research. We classified these reasons into five categories and, within these, identified 12 broad and 31 narrow reason types.

15% of the retrieved passages contained reasons in favor of conducting chimera research (Category P), while 85% of the passages contained reasons against it. The reasons against conducting chimera research fell into four further categories: reasons concerning the creation of a chimera (Category A), its treatment (Category B), reasons referring to metaphysical or social issues resulting from its existence (Category C) and to potential downstream effects of chimera research (Category D). A significant proportion of identified passages (46%) fell under Category C.

Conclusions

We hope that our results, in revealing the conceptual and argumentative structure of the debate and highlighting some its most notable tendencies and prominent positions, will facilitate continued discussion and provide a basis for the development of relevant policy and legislation.

Ethical Challenges of Germline Genetic Enhancement

The new reproductive technologies have opened the door to different processes of germline genetic enhancement by which the characteristics of an individual according to the interests of the agents involved could be selected during its gestation. Although the initiative is apparently oriented towards developing individuals that would excel in society, critical voices raise the concerns about that this approach would generate and need for a reflection on the ethical, social and legal implications of these techniques and their implementation in society. We reviewed the literature about these issues throughout their historical records to date, focusing on the moral arguments and non-clinical aspects that affect the legal and social environment. We have observed various trends of thought with divergent positions (proactive, preventive, and regulatory) as well as a large number of articles that try to reconcile the different approaches. This review illustrates a series of concepts from the ethics and philosophy fields which are frequently used in studies that evaluate the ethical implications of germline genetic enhancement, such as dignity, benefit, autonomy, and identity. In addition, amongst the many unresolved controversies surrounding genetic enhancement, we identify procreative beneficence, genetic disassociation, gender selection, the value of disability, embryo chimerization, and the psychosocial inequality of potentially enhanced individuals as crucial. We also develop possible scenarios for future debate. We consider especially important the definition and specification of three aspects which are essential for the deployment of new reproductive technologies: the moral status of the embryo undergoing enhancement, the legal status of the enhanced individual, and the responsibility of the agents executing the enhancement. Finally, we propose the precautionary principle as a means to navigate ethical uncertainties.

Moral uncertainty and the farming of human-pig chimeras

It may soon be possible to generate human organs inside of human-pig chimeras via a process called interspecies blastocyst complementation. This paper discusses what arguably the central ethical concern is raised by this potential source of transplantable organs: that farming human-pig chimeras for their organs risks perpetrating a serious moral wrong because the moral status of human-pig chimeras is uncertain, and potentially significant. Those who raise this concern usually take it to be unique to the creation of chimeric animals with 'humanised' brains. In this paper, we show how that the same style of argument can be used to critique current uses of non-chimeric pigs in agriculture. This reveals an important tension between two common moral views: that farming human-pig chimeras for their organs is ethically concerning, and that farming non-chimeric pigs for food or research is ethically benign. At least one of these views stands in need of revision.

Ethical issues in genetic modification and why application matters

Advances in genome editing techniques have generated renewed interest in the ethical implications of genetic modification. In this article, we review the recent literature and discuss in detail ethical issues pertaining to the application of this technology to five areas; human embryo research, organoid research, the prospect of genetically modified babies, mitochondrial replacement therapy and the creation of chimeric organisms. We point to a central issue which cuts through these different areas: the need to clearly frame how using the technology provides benefit that cannot be met by other means. Failure to provide reasonable justification, and address how risks-if any-will be mitigated, is likely to erode public trust and undermine progress in medical research and its clinical translation.

The contribution of human/non-human animal chimeras to stem cell research

Chimeric animals are made up of cells from two separate zygotes. Human/non-human animal chimeras have been used for a number of research purposes, including human disease modeling. Pluripotent stem cell (PSC) research has relied upon the chimera approach to examine the developmental potential of stem cells, to determine the efficacy of cell replacement therapies, and to establish a means of producing human organs. Based on ethical issues, this work has faced pushback from various sources including funding agencies. We discuss here the essential role these studies have played, from gaining a better understanding of human biology to providing a stepping stone to human disease treatments. We also consider the major ethical issues, as well as the current status of support for this work in the United States.

Public attitudes in Japan towards human-animal chimeric embryo research using human induced pluripotent stem cells

AIM

To understand the steps and objectives for which Japanese people are willing to accept human-animal chimeric embryo research using human induced pluripotent stem cells.

METHODS

An internet-based survey was conducted for the general public and researchers in Japan in 2016.

RESULTS

Over 60% of the public and 83.8% of researchers supported the creation of human-swine chimeras and 81.0% of the public and 92.4% of researchers supported the creation of human-swine chimeric embryos.

DISCUSSION

When presented with a graded view of human-swine chimeric embryo research with concomitant, specific objectives, a large majority of the general public as well as researchers are willing to accept this research with the aims of disease study, novel drug and treatment development, and transplantation.

Balancing Ethical Pros and Cons of Stem Cell Derived Gametes

In this review we aim to provide an overview of the most important ethical pros and cons of stem cell derived gametes (SCD-gametes), as a contribution to the debate about reproductive tissue engineering. Derivation of gametes from stem cells holds promising applications both for research and for clinical use in assisted reproduction. We explore the ethical issues connected to gametes derived from embryonic stem cells (both patient specific and non-patient specific) as well as those related to gametes derived from induced pluripotent stem cells. The technology of SCD-gametes raises moral concerns of how reproductive autonomy relates to issues of embryo destruction, safety, access, and applications beyond clinical infertility.

Emerging ethical perspectives in the clustered regularly interspaced short palindromic repeats genome-editing debate

This paper provides an overview of the ethical issues in the international clustered regularly interspaced short palindromic repeats (CRISPR) genome editing debate from March 2015 to September 2016. We present the regulatory framework for embryo research in the UK, and explain why CRISPR is not a significant break with the past. We discuss the ethical issues arising from CRISPR applications beyond human embryos, namely the use of gene drive-engineered mosquitoes to eradicate diseases, engineering nonhuman animals to harvest organs for human transplant and engineering crops. We discuss the experiments that have demonstrated the technical feasibility of cultivating embryos in vitro for up to 14 days, and possibly beyond this limit, and the ethical issues arising from the proposal to extend the limit beyond 14 days.