An overview of the role of society and risk in xenotransplantation

The public you want, the public you get: Exploring the relationship between the public and science in the debate on xenotransplantation

The debate that followed the first-in-human cardiac transplantation of a genetically modified pig organ emerged as a discussion of social justice when the patient's criminal record was revealed. This article aims to make sense of this debate by understanding the role of the 'public' today, particularly in relation to the governance of biotechnology. The relationship between the public and science is increasingly mediated through citizen participation. However, the public debate that unfolded on matters of social justice can be seen as an unmediated public discourse, which carries the risk of producing unpredictable outcomes. The content of the debate gains significance due to the functional differentiation of society. The medical subsystem does not consider the patient's history in terms of their involvement in the legal sphere, that is, their criminal record. Nevertheless, normative judgements are transferred across functional systems, allowing for the influence of public opinion and the potential for public scorn.

Organ transplants of the future: planning for innovations including xenotransplantation

The future clinical application of animal-to-human transplantation (xenotransplantation) is of importance to society as a whole. Favourable preclinical data relevant to cell, tissue and solid organ xenotransplants have been obtained from many animal models utilizing genetic engineering and protocols of pathogen-free husbandry. Findings have reached a tipping point, and xenotransplantation of solid organs is approaching clinical evaluation, the process of which now requires close deliberation. Such discussions include considering when there is sufficient evidence from preclinical animal studies to start first-in-human xenotransplantation trials. The present article is based on evidence and opinions formulated by members of the European Society for Organ Transplantation who are involved in the Transplantation Learning Journey project. The article includes a brief overview of preclinical concepts and biology of solid organ xenotransplantation, discusses the selection of candidates for first-in-human studies and considers requirements for study design and conduct. In addition, the paper emphasizes the need for a regulatory framework for xenotransplantation of solid organs and the essential requirement for input from public and patient stakeholders.

Corneal xenotransplantation: Where are we standing?

The search for alternatives to allotransplants is driven by the shortage of corneal donors and is demanding because of the limitations of the alternatives. Indeed, current progress in genetically engineered (GE) pigs, the introduction of gene-editing technology by clustered regularly interspaced short palindromic repeats (CRISPR)-Cas9, and advanced immunosuppressants have made xenotransplantation a possible option for a human trial. Porcine corneal xenotransplantation is considered applicable because the eye is regarded as an immune-privileged site. Furthermore, recent non-human primate studies have shown long-term survival of porcine xenotransplants in keratoplasty. Herein, corneal immune privilege is briefly introduced, and xenogeneic reactions are compared with allogeneic reactions in corneal transplantation. This review describes the current knowledge on special issues of xenotransplantation, xenogeneic rejection mechanisms, current immunosuppressive regimens of corneal xenotransplantation, preclinical efficacy and safety data of corneal xenotransplantation, and updates of the regulatory framework to conduct a clinical trial on corneal xenotransplantation. We also discuss barriers that might prevent xenotransplantation from becoming common practice, such as ethical dilemmas, public concerns on xenotransplantation, and the possible risk of xenozoonosis. Given that the legal definition of decellularized porcine cornea (DPC) lies somewhere between a medical device and a xenotransplant, the preclinical efficacy and clinical trial data using DPC are included. The review finally provides perspectives on the current standpoint of corneal xenotransplantation in the fields of regenerative medicine.

Justifying clinical trials for porcine islet xenotransplantation

The development of the Edmonton Protocol encouraged a great deal of optimism that a cell-based cure for type I diabetes could be achieved. However, donor organ shortages prevent islet transplantation from being a widespread solution as the supply cannot possibly equal the demand. Porcine islet xenotransplantation has the potential to address these shortages, and recent preclinical and clinical trials show promising scientific support. Consequently, it is important to consider whether the current science meets the ethical requirements for moving toward clinical trials. Despite the potential risks and the scientific unknowns that remain to be investigated, there is optimism regarding the xenotransplantation of some types of tissue, and enough evidence has been gathered to ethically justify clinical trials for the most safe and advanced area of research, porcine islet transplantation. Researchers must make a concerted effort to maintain a positive image for xenotransplantation, as a few well-publicized failed trials could irrevocably damage public perception of xenotransplantation. Because all of society carries the burden of risk, it is important that the public be involved in the decision to proceed. As new information from preclinical and clinical trials develops, policy decisions should be frequently updated. If at any point evidence shows that islet xenotransplantation is unsafe, then clinical trials will no longer be justified and they should be halted. However, as of now, the expected benefit of an unlimited supply of islets, combined with adequate informed consent, justifies clinical trials for islet xenotransplantation.

Extracellular Matrix Revisited: Roles in Tissue Engineering

The extracellular matrix (ECM) is a heterogeneous, connective network composed of fibrous glycoproteins that coordinate in vivo to provide the physical scaffolding, mechanical stability, and biochemical cues necessary for tissue morphogenesis and homeostasis. This review highlights some of the recently raised aspects of the roles of the ECM as related to the fields of biophysics and biomedical engineering. Fundamental aspects of focus include the role of the ECM as a basic cellular structure, for novel spontaneous network formation, as an ideal scaffold in tissue engineering, and its essential contribution to cell sheet technology. As these technologies move from the laboratory to clinical practice, they are bound to shape the vast field of tissue engineering for medical transplantations.

Islet Xeno/transplantation and the risk of contagion: local responses from Canada and Australia to an emerging global technoscience

This paper situates the public debate over the use of living animal organs and tissue for human therapies within the history of experimental islet transplantation. Specifically, the paper compares and contrasts the Canadian and Australian responses on xenotransplantation to consider what lessons can be learnt about the regulation of a complex and controversial biotechnology. Sobbrio and Jorqui described public engagement on xenotransplantation in these countries as 'important forms of experimental democracy.' While Canada experimented with a novel nation-wide public consultation, Australia sought public input within the context of a national inquiry. In both instances, the outcome was a temporary moratorium on all forms of clinical xenotransplantation comparable to the policies adopted in some European countries. In addition, the Australian xenotransplantation ban coincided with a temporary global ban on experimental islet allotransplantation in 2007. Through historical and comparative research, this paper investigates how public controversies over organ and tissue transplantation can inform our understanding of the mediation of interspeciality and the regulation of a highly contested technoscience. It offers an alternative perspective on the xenotransplantation controversy by exploring the ways in which coinciding moratoriums on islet allograft and xenograft challenge, complicate and confound our assumptions regarding the relationships between human and animal, between routine surgery and clinical experimentation, between biomedical science and social science, and between disease risks and material contagion.