Bioethics of organ transplantation

Ethical analysis of the first porcine cardiac xenotransplantation

In this article, we provide an ethical analysis of the first porcine cardiac xenotransplant, performed in Maryland, USA in early 2022. David Bennett was offered the experimental procedure after he was deemed ineligible for human heart transplantation and mechanical circulatory support, based on a history of non-compliance. It was reported that Mr Bennett's previous instances of non-compliance were for medically non-life-threatening conditions years earlier, where the risks of non-compliance were not as high. We argue that, in Mr Bennett's case, a history of non-compliance in a different context, should not necessarily rule him ineligible for a potentially life-saving treatment now. Furthermore, using previous non-compliance to exclude individuals from donor organs may have the unintended effect of placing the burden of testing xenotransplantation on those who are already disadvantaged. We then argue that it is not enough to rely on patient consent to ethically justify xenotransplantation research. Taking a broad ethical perspective is crucial when mapping a clinical pathway for xenotransplantation.

Pig-to-human heart xenotransplantation in two recently deceased human recipients

Genetically modified xenografts are one of the most promising solutions to the discrepancy between the numbers of available human organs for transplantation and potential recipients. To date, a porcine heart has been implanted into only one human recipient. Here, using 10-gene-edited pigs, we transplanted porcine hearts into two brain-dead human recipients and monitored xenograft function, hemodynamics and systemic responses over the course of 66 hours. Although both xenografts demonstrated excellent cardiac function immediately after transplantation and continued to function for the duration of the study, cardiac function declined postoperatively in one case, attributed to a size mismatch between the donor pig and the recipient. For both hearts, we confirmed transgene expression and found no evidence of cellular or antibody-mediated rejection, as assessed using histology, flow cytometry and a cytotoxic crossmatch assay. Moreover, we found no evidence of zoonotic transmission from the donor pigs to the human recipients. While substantial additional work will be needed to advance this technology to human trials, these results indicate that pig-to-human heart xenotransplantation can be performed successfully without hyperacute rejection or zoonosis.

Modeling and Validation of an Ultra-Compact Regenerative Liver Dialysis Device

The availability of a wearable artificial liver that facilitates extracorporeal dialysis outside of medical facilities would represent a significant advancement for patients requiring dialysis. The objective of this preliminary investigation is to explore, using validated mathematical models based on in vitro data, the feasibility of developing a novel, cost-effective, and highly compact extracorporeal liver support device that can be employed as a transitional therapy to transplantation outside of clinical settings. Such an innovation would offer substantial cost savings to the national healthcare system while significantly improving the patient's quality of life. The experimental components consisted of replacing traditional adsorbent materials with albumin-functionalized silica microspheres due to their capacity to adsorb bilirubin, one of the toxins responsible for liver failure. Two configurations of the dialysis module were tested: one involved dispersing the adsorbent particles in dialysis fluid, while the other did not require dialysis fluid. The results demonstrate the superior performance of the first configuration compared to the second. Although the clinical applicability of these models remains distant from the current stage, further studies will focus on optimizing these models to develop a more compact and wearable device.

Towards machine learning for moral choice analysis in health economics: A literature review and research agenda

BACKGROUND

Discrete choice models (DCMs) for moral choice analysis will likely lead to erroneous model outcomes and misguided policy recommendations, as only some characteristics of moral decision-making are considered. Machine learning (ML) is recently gaining interest in the field of discrete choice modelling. This paper explores the potential of combining DCMs and ML to study moral decision-making more accurately and better inform policy decisions in healthcare.

METHODS

An interdisciplinary literature search across four databases - PubMed, Scopus, Web of Science, and Arxiv - was conducted to gather papers. Based on the Preferred Reporting Items for Systematic and Meta-analyses (PRISMA) guideline, studies were screened for eligibility on inclusion criteria and extracted attributes from eligible papers. Of the 6285 articles, we included 277 studies.

RESULTS

DCMs have shortcomings in studying moral decision-making. Whilst the DCMs' mathematical elegance and behavioural appeal hold clear interpretations, the models do not account for the 'moral' cost and benefit in an individual's utility calculation. The literature showed that ML obtains higher predictive power, model flexibility, and ability to handle large and unstructured datasets. Combining the strengths of ML methods with DCMs has the potential for studying moral decision-making.

CONCLUSIONS

By providing a research agenda, this paper highlights that ML has clear potential to i) find and deepen the utility specification of DCMs, and ii) enrich the insights extracted from DCMs by considering the intrapersonal determinants of moral decision-making.

Standing on Both Sides: Analysis of a Transplant Coordinator's Ethical Position Between the Recipient and the Donor's Family

BACKGROUND

When an organ is harvested from a deceased donor, how should transplant coordinators handle the issue of contact between the donor's family and the organ recipient?

METHODS

The authors-qualified both by their own considerable practical experience and theoretical investigation-discussed various aspects of the problem, relating to the bioethical issues as well as the practical dilemmas that must be clarified and decided.

RESULTS

They proposed a strategy whereby transplant coordinators can analyze their own philosophical attitude toward the issue and respond accordingly in their work to the needs and preferences of both parties.

CONCLUSIONS

The professionals handling the transplant process need training tailored to the bioethical issues relevant to the challenges they are likely to confront. This training must consist not only of theoretical and ethical guidance but also simulations designed to clarify the clinician's own personal belief system and raise awareness and self-reflection of their own biases.

Results of Two Cases of Pig-to-Human Kidney Xenotransplantation

BACKGROUND

Xenografts from genetically modified pigs have become one of the most promising solutions to the dearth of human organs available for transplantation. The challenge in this model has been hyperacute rejection. To avoid this, pigs have been bred with a knockout of the alpha-1,3-galactosyltransferase gene and with subcapsular autologous thymic tissue.

METHODS

We transplanted kidneys from these genetically modified pigs into two brain-dead human recipients whose circulatory and respiratory activity was maintained on ventilators for the duration of the study. We performed serial biopsies and monitored the urine output and kinetic estimated glomerular filtration rate (eGFR) to assess renal function and xenograft rejection.

RESULTS

The xenograft in both recipients began to make urine within moments after reperfusion. Over the 54-hour study, the kinetic eGFR increased from 23 ml per minute per 1.73 m² of body-surface area before transplantation to 62 ml per minute per 1.73 m² after transplantation in Recipient 1 and from 55 to 109 ml per minute per 1.73 m² in Recipient 2. In both recipients, the creatinine level, which had been at a steady state, decreased after implantation of the xenograft, from 1.97 to 0.82 mg per deciliter in Recipient 1 and from 1.10 to 0.57 mg per deciliter in Recipient 2. The transplanted kidneys remained pink and well-perfused, continuing to make urine throughout the study. Biopsies that were performed at 6, 24, 48, and 54 hours revealed no signs of hyperacute or antibody-mediated rejection. Hourly urine output with the xenograft was more than double the output with the native kidneys.

CONCLUSIONS

Genetically modified kidney xenografts from pigs remained viable and functioning in brain-dead human recipients for 54 hours, without signs of hyperacute rejection. (Funded by Lung Biotechnology.).

Ethics of Organ Transplantation in Persons with Intellectual Disability

Historically, individuals with intellectual disability and end-stage organ disease were discriminated against by transplant professionals and often excluded from transplantation waitlists. Despite antidiscrimination legislation, some transplant programs continue to include intellectual disability as a relative, if not an absolute, contraindication to listing for an organ; this is true for both pediatric and adult individuals in end-stage organ disease. This commentary opposes the absolute exclusion of patients with intellectual disability and end-stage organ disease from transplantation waitlists provided that the candidates are expected to gain a predefined minimum benefit threshold of life-years and quality-adjusted-life years. Intellectual disability is one of many factors that should be considered in determining transplant eligibility and each candidate should have an individualized interdisciplinary assessment.

Psychosocial considerations in the assessment of hand transplant candidates: A single-center experience and brief literature review

Vascularized composite allograft, including hand transplantation (HT), has gained wider usage as a reconstructive treatment over the past 30 years. HT recipients face unique psychosocial challenges compared to their solid organ and/or bone marrow transplant counterparts. Accordingly, the psychosocial evaluation among HT candidates continues to evolve, leaving a lack of consensus as to the critical psychosocial domains and psychometric testing instruments to help evaluate individuals considering HT. The present manuscript describes the psychosocial evaluation process within the Duke HT program, which been contacted by 80 potential candidates since 2014. The Duke HT evaluation process incorporates a comprehensive psychosocial assessment within domains including personality, cognitive function, mood, behavioral adherence, social support, and substance use history, among others. Our experience underscores the potential utility of collecting thorough psychosocial evaluations, supplemented by psychometric test data, to comprehensively assess potential HT candidates.

Chimeric Humanized Vasculature and Blood: The Intersection of Science and Ethics

The only curative therapy for diseases such as organ failure is orthotopic organ transplantation. Organ transplantation has been limited due to the shortage of donor organs. The huge disparity between those who need and those who receive transplantation therapy drives the pursuit of alternative treatments. Therefore, novel therapies are warranted. Recent studies support the feasibility of generating human-porcine chimeras that one day would provide humanized vasculature and blood for transplantation and serve as important research models. The ethical issues they raise require open discussion and dialog lest promising lines of inquiry flounder due to unfounded fears or compromised public trust.

The Role of the Family in Deceased Organ Procurement: A Guide for Clinicians and Policymakers

Families play an essential role in deceased organ procurement. As the person cannot directly communicate his or her wishes regarding donation, the family is often the only source of information regarding consent or refusal. We provide a systematic description and analysis of the different roles the family can play, and actions the family can take, in the organ procurement process across different jurisdictions and consent systems. First, families can inform or update healthcare professionals about a person's donation wishes. Second, families can authorize organ procurement in the absence of deceased's preferences and the default is not to remove organs, and oppose donation where there is no evidence of preference but the default is to presume consent; in both cases, the decision could be based on their own wishes or what they think the deceased would have wanted. Finally, families can overrule the known wishes of the deceased, which can mean preventing donation, or permitting donation when the deceased refused it. We propose a schema of 4 levels on which to map these possible family roles: no role, witness, surrogate, and full decisional authority. We conclude by mapping different jurisdictions onto this schema to provide a more comprehensive understanding of the consent system for organ donation and some important nuances about the role of families. This classificatory model aims to account for the majority of the world's consent systems. It provides conceptual and methodological guidance that can be useful to researchers, professionals, and policymakers involved in organ procurement.

Organ Transplantation in Iran; Current State and Challenges with a View on Ethical Consideration

Organ transplantation is a new issue in medical science. It is an important achievement and a sign of the progression and ability of medical centers around the world. Governments, populations, the medical community and people involved in culture, art, and media all have a decisive role in the culture of organ donation, which is the only way to guarantee that the healthy organs of a brain-dead person can continue to work and save the lives of people in need of organ transplantation. The brain death phenomenon and its possible application in organ transplantation, while offering new hope for the salvation of a number of patients, has led to many ethical, cultural, and legal issues. Ethical issues in organ transplantation are very complicated due to many social factors such as religion, culture, and traditions of the affected communities. The ethical and legal points of removing organs from the body of a living or cadaveric source, the definition of brain death, the moral and legal conditions of the donor and the recipient, and the financial relationship between them and many others, are all critical issues in organ transplantation. While there may be no available explicit solution to these issues, they should be rigorously considered by the experts. Efforts to systematically eliminate barriers and solve problems in organ transplantation, can not only reduce the costs of maintaining brain-dead patients and encourage patients that need organ transplantation but can also prevent immoral and illegal activities. In this paper, we have reviewed the most important and current challenges in organ transplantation with a view to the ethical considerations, and we have suggested some strategies to extend it in Iran.