The moral status of human embryo-like structures: potentiality matters?: The moral status of human synthetic embryos

Stem cell-derived embryo models: moral advance or moral obfuscation?

Stem cell-derived embryo models (SCEMs) are model embryos used in scientific research to gain a better understanding of early embryonic development. The way humans develop from a single-cell zygote to a complex multicellular organism remains poorly understood. However, research looking at embryo development is difficult because of restrictions on the use of human embryos in research. Stem cell embryo models could reduce the need for human embryos, allowing us to both understand early development and improve assisted reproductive technologies. There have been several rapid advances in creating SCEMs in recent years. These advances potentially provide a new avenue to study early human development. The benefits of SCEMs are predicated on the claim that they are different from embryos and should, therefore, be exempt from existing regulations that apply to embryos (such as the 14-day rule). SCEMs are proposed as offering a model that can capture the inner workings of the embryo but lack its moral sensitivities. However, the ethical basis for making this distinction has not been clearly explained. In this current controversy, we focus on the ethical justification for treating SCEMs differently to embryos, based on considerations of moral status.

Potentiality switches and epistemic uncertainty: the Argument from Potential in times of human embryo-like structures

Recent advancements in developmental biology enable the creation of embryo-like structures from human stem cells, which we refer to as human embryo-like structures (hELS). These structures provide promising tools to complement-and perhaps ultimately replace-the use of human embryos in clinical and fundamental research. But what if these hELS-when further improved-also have a claim to moral status? What would that imply for their research use? In this paper, we explore these questions in relation to the traditional answer as to why human embryos should be given greater protection than other (non-)human cells: the so-called Argument from Potential (AfP). According to the AfP, human embryos deserve special moral status because they have the unique potential to develop into persons. While some take the development of hELS to challenge the very foundations of the AfP, the ongoing debate suggests that its dismissal would be premature. Since the AfP is a spectrum of views with different moral implications, it does not need to imply that research with human embryos or hELS that (may) have 'active' potential should be completely off-limits. However, the problem with determining active potential in hELS is that this depends on development passing through 'potentiality switches' about the precise coordinates of which we are still in the dark. As long as this epistemic uncertainty persists, extending embryo research regulations to research with specific types of hELS would amount to a form of regulative precaution that as such would require further justification.

Human blastoid as an in vitro model of human blastocysts

Human development is a highly coordinated process, with any abnormalities during the early embryonic stages that can often have detrimental consequences. The complexity and nuances of human development underpin its significance in embryo research. However, this research is often hindered by limited availability and ethical considerations associated with the use of donated blastocysts from in vitro fertilization (IVF) surplus. Human blastoids offer promising alternatives as they can be easily generated and manipulated in the laboratory while preserving key characteristics of human blastocysts. In this way, they hold the potential to serve as a scalable and ethically permissible resource in embryology research. By utilizing such human embryo models, we can establish a transformative platform that complements the study with IVF embryos, ultimately enhancing our understanding of human embryogenesis.

[Some present and future ethical dilemmas surrounding advancements in in vitro fertilization.]

The growing field of assisted human reproduction has achieved unimaginable milestones. Its continuous development and the innovations it generates at times pose both ethical and legal dilemmas. This essay aims to elucidate the progressive changes occurring in the realm of the origin of life due to the development of new options and strategies in assisted human reproduction. First, it constructs an interdisciplinary reflection on human nature and the changes society faces from the perspectives of science, ethics, and law, particularly from the perspective of Spain. Second, it provides a brief overview of current or future biomedical techniques in the field of human reproduction. It concludes with a discussion of the need to reflect on the rapid advancement of science in assisted human reproduction.

Ethical Aspects of Human Induced Pluripotent Stem Cells and Alzheimer's Disease: Potentials and Challenges of a Seemingly Harmless Method

Dementia currently affects more than 55 million people worldwide, and scientists predict that this number will continue to rise. The most common form is Alzheimer's disease (AD), which is triggered, among other things, by dysfunctional cells in the human brain. Stem cell research attempts to counteract neurodegenerative processes, for example by replacing or treating diseased cells. In addition to human embryonic stem cells, since the successes of Takahashi and Yamanaka in 2006, there has been an increased focus on human induced pluripotent stem cells (hiPS cells). These cells avoid ethically challenging questions about the moral status of human embryos, but there are numerous problems, such as high production costs, side effects from the reprogramming process, or a potentially new moral status. These ethical issues will be examined primarily in relation to AD. The first part will be a discussion of hiPS cells and their importance for stem cell research, after which the focus turns to AD. Based on scientific studies, the relationship between hiPS cells and AD will be outlined as well as ethical implications presented. While potential limitations of hiPS cells have been discussed by numerous authors, an ethical perspective on the link between hiPS cells and AD seems to be neglected in the scientific community. The following risk analysis aims to identify a possible research agenda. In conclusion, the focus on individuals with AD may help to adopt an ethical stance that recognizes existing limitations and constructively engages with the possibilities of research.

The Prospects of Artificial Consciousness: Ethical Dimensions and Concerns

Can machines be conscious and what would be the ethical implications? This article gives an overview of current robotics approaches toward machine consciousness and considers factors that hamper an understanding of machine consciousness. After addressing the epistemological question of how we would know whether a machine is conscious and discussing potential advantages of potential future machine consciousness, it outlines the role of consciousness for ascribing moral status. As machine consciousness would most probably differ considerably from human consciousness, several complex questions must be addressed, including what forms of machine consciousness would be morally relevant forms of consciousness, and what the ethical implications of morally relevant forms of machine consciousness would be. While admittedly part of this reflection is speculative in nature, it clearly underlines the need for a detailed conceptual analysis of the concept of artificial consciousness and stresses the imperative to avoid building machines with morally relevant forms of consciousness. The article ends with some suggestions for potential future regulation of machine consciousness.

Cadaveric Stem Cells: Their Research Potential and Limitations

In the era of growing interest in stem cells, the availability of donors for transplantation has become a problem. The isolation of embryonic and fetal cells raises ethical controversies, and the number of adult donors is deficient. Stem cells isolated from deceased donors, known as cadaveric stem cells (CaSCs), may alleviate this problem. So far, it was possible to isolate from deceased donors mesenchymal stem cells (MSCs), adipose delivered stem cells (ADSCs), neural stem cells (NSCs), retinal progenitor cells (RPCs), induced pluripotent stem cells (iPSCs), and hematopoietic stem cells (HSCs). Recent studies have shown that it is possible to collect and use CaSCs from cadavers, even these with an extended postmortem interval (PMI) provided proper storage conditions (like cadaver heparinization or liquid nitrogen storage) are maintained. The presented review summarizes the latest research on CaSCs and their current therapeutic applications. It describes the developments in thanatotranscriptome and scaffolding for cadaver cells, summarizes their potential applications in regenerative medicine, and lists their limitations, such as donor’s unknown medical condition in criminal cases, limited differentiation potential, higher risk of carcinogenesis, or changing DNA quality. Finally, the review underlines the need to develop procedures determining the safe CaSCs harvesting and use.

Embryoid research calls for reassessment of legal regulations

It is known that in countries, in which basic research on human embryos is in fact prohibited by law, working with imported human embryonic stem cells (hESCs) can still be permitted. As long as hESCs are not capable of development into a complete human being, it might be the case that they do not fulfill all criteria of the local definition of an embryo. Recent research demonstrates that hESCs can be developed into entities, called embryoids, which increasingly could come closer to actual human embryos in future. By discussing the Austrian situation, we want to highlight that current embryoid research could affect the prevailing opinion on the legal status of work with hESCs and therefore calls for reassessment of the regulations in all countries with comparable definitions of the embryo.

Human embryo research, stem cell-derived embryo models and in vitro gametogenesis: Considerations leading to the revised ISSCR guidelines

The ISSCR Guidelines for Stem Cell Research and Clinical Translation were last revised in 2016. Since then, rapid progress has been made in research areas related to in vitro culture of human embryos, creation of stem cell-based embryo models, and in vitro gametogenesis. Therefore, a working group of international experts was convened to review the oversight process and provide an update to the guidelines. This report captures the discussion and summarizes the major recommendations made by this working group, with a specific emphasis on updating the categories of review and engagement with the specialized scientific and ethical oversight process.

Capturing human trophoblast development with naive pluripotent stem cells in vitro

Trophoblasts are extraembryonic cells that are essential for maintaining pregnancy. Human trophoblasts arise from the morula as trophectoderm (TE), which, after implantation, differentiates into cytotrophoblasts (CTs), syncytiotrophoblasts (STs), and extravillous trophoblasts (EVTs), composing the placenta. Here we show that naïve, but not primed, human pluripotent stem cells (PSCs) recapitulate trophoblast development. Naive PSC-derived TE and CTs (nCTs) recreated human and monkey TE-to-CT transition. nCTs self-renewed as CT stem cells and had the characteristics of proliferating villous CTs and CTs in the cell column of the first trimester. Notably, although primed PSCs differentiated into trophoblast-like cells (BMP4, A83-01, and PD173074 [BAP]-treated primed PSCs [pBAPs]), pBAPs were distinct from nCTs and human placenta-derived CT stem cells, exhibiting properties consistent with the amnion. Our findings establish an authentic paradigm for human trophoblast development, demonstrating the invaluable properties of naive human PSCs. Our system provides a platform to study the molecular mechanisms underlying trophoblast development and related diseases.

The ethics of human-embryoids model: a call for consistency

In this article, we discuss the ethics of human embryoids, i.e., embryo-like structures made from pluripotent stem cells for modeling natural embryos. We argue that defining our social priorities is critical to design a consistent ethical guideline for research on those new entities. The absence of clear regulations on these emerging technologies stems from an unresolved debate surrounding natural human embryo research and one common opinion that one needs to solve the question of the moral status of the human embryo before regulating their surrogate. The recent NIH funding restrictions for research on human embryoids have made scientists even more unlikely to raise their voices. As a result, the scientific community has maintained a low profile while longing for a more favorable socio-political climate for their research. This article is a call for consistency among biomedical research on human materials, trying to position human embryoids within a spectrum of existing practice from stem cell research or IVF to research involving human subjects. We specifically note that the current practices in infertility clinics of freezing human embryos or disposing of them without any consideration for their potential benefits contradicts the assumption of special consideration for human material. Conversely, creating human embryoids for research purposes could ensure that no human material be used in vain, always serving humankind. We argue here that it is time to reconsider the full ban on embryo research (human embryos and embryoids) beyond the 14-day rule and that research on those entities should obey a sliding scale combining the completeness of the model (e.g., complete vs. partial) and the developmental stage: with more advanced completeness and developmental stage of the considered entity, being associated with more rigorous evaluation of societal benefits, statements of intention, and necessity of such research.

Modeling human embryo development with embryonic and extra-embryonic stem cells

Early human post-implantation development involves extensive growth combined with a series of complex morphogenetic events. The lack of precise spatial and temporal control over these processes leads to pregnancy loss. Given the ethical and technical limitations in studying the natural human embryo, alternative approaches are needed to investigate mechanisms underlying this critical stage of human development. Here, we present an overview of the different stem cells and stem cell-derived models which serve as useful, albeit imperfect, tools in understanding human embryogenesis. Current models include stem cells that represent each of the three earliest lineages: human embryonic stem cells corresponding to the epiblast, hypoblast-like stem cells and trophoblast stem cells. We also review the use of human embryonic stem cells to model complex aspects of epiblast morphogenesis and differentiation. Additionally, we propose that the combination of both embryonic and extra-embryonic stem cells to form three-dimensional embryo models will provide valuable insights into cell-cell chemical and mechanical interactions that are essential for natural embryogenesis.

The moral status of human embryo-like structures: potentiality matters?: The moral status of human synthetic embryos

New techniques to generate and culture embryo-like structures from stem cells require a more fine-grained distinction of potential to define the moral status of these structures.