Racial differences in attitudes to clinical pig organ Xenotransplantation

Construction and Validation of a Predictive Model for the Acceptance of Kidney Xenotransplantation by Medical Staff

With gene editing technology and immunosuppressive drugs, kidney xenotransplantation has developed rapidly in recent years. However, as the most cutting-edge medical personnel, there are few reports on the acceptance and awareness of kidney xenotransplantation. This study conducted an online questionnaire survey on medical staff and constructed the first predictive model for the acceptance of kidney xenotransplantation by medical staff through univariate and multivariate analysis of each variable. Their acceptance rate is 72.8%, and it was found that the willingness to donate organs, awareness of kidney xenotransplantation, and residential areas are independent factors affecting their acceptance rate. In addition, the study also found that although healthcare workers have a high acceptance and willingness to share, their awareness of kidney xenotransplantation is relatively low. This reminds us that in order to increase public acceptance of xenotransplantation, the first step is to start with promoting xenotransplantation among medical personnel.

Engineering organs, hopes and hybridity: considerations on the social potentialities of xenotransplantation

The development of replacing human organs with those from genetically modified pigs holds immense potential for alleviating the shortage of organs necessary for patients in need of transplants. This medical advancement is also accompanied by significant social changes, including the emergence of a bioeconomy, new modes of biotechnology governance, altered human-animal relations and increased public engagement. Some aspects, such as the impact on the transplant allocation system, effects on clinical practice and healthcare provision, global trajectories and most importantly the consequences for patients and their families remain unpredictable. Given that xenotransplantation occurs within a societal context and its success or failure will not be confined to technical feasibility alone, it is essential to engage a social sciences perspective to highlight the social implications and emphasise the importance of social research in accompanying future developments.

Transplant Patients' Perceptions About Participating in First-in-Human Pig Kidney Xenotransplant Clinical Trials: A Mixed Methods Study

First-in-human pig xenotransplant clinical trials may soon begin, which raises ethical concerns about patients' decision-making to participate in such trials. We assessed kidney transplant candidates' attitudes and hypothetical decision-making about participating in xenotransplant trials through semi-structured telephone interviews and an online survey. We analyzed qualitative data by thematic analysis and quantitative data by descriptive statistics. Twenty-eight patients participated in interviews; 142 patients participated in the survey. Most interview and survey respondents were male (68%, 56%), White (54%, 61%), or Black (36%, 22%). Although interview participants appreciated xenotransplantation research's potential to advance science, they expressed concerns about infection transmission and graft function. Few survey respondents were willing to participate in a pig kidney trial to test the safety of pig kidneys (12.6%) or pig kidney function (16.9%). Interview participants would be more likely to participate in a first-in-human pig kidney trial if receiving a human kidney was unlikely and their health status declined. Willingness would also depend on how long the pig kidney would function. Most interview participants were receptive to long-term monitoring, but not to family monitoring. Transplant programs planning xenotransplant trials should anticipate these types of concerns for optimizing human subject protections and conducting a robust informed consent process.

Public attitudes to xenotransplantation: A national survey in the United States

Xenotransplantation (XTx) presents a potential clinical alternative to the shortage of human organs for transplantation. Before clinical trials occur in the United States, public assessments are crucial to understand potential barriers to acceptance. The purpose of this study was to explore barriers and identify characteristics associated with attitudes toward XTx. A survey assessing demographic characteristics and attitudes toward XTx was distributed to a nationally representative sample of adults aged ≥18 years in the United States. Regression analysis was employed to identify characteristics associated with attitudes toward XTx. Between May 25 and June 14, 2023, 5008 respondents completed the survey. Importantly, half of the respondents expressed low or no knowledge of either transplantation or XTx. Approximately 40% expressed discomfort with receiving a pig organ for themselves or a loved one. Despite a lack of xenotransplant outcome data, 36% were open to experimental XTx if they needed a transplant. However, 57% rated lack of current evidence of success or fear of complications as top concerns. Regression models consistently associated being younger, female, not needing an organ, or being a member of a racial minority group with lower acceptance. This survey is the largest to date exploring public attitudes toward XTx. Despite overall acceptance, concerns persist. Increasing public acceptance is key as the field advances.

Update on the ethical, legal and technical challenges of translating xenotransplantation

This manuscript reports on a landmark symposium on the ethical, legal and technical challenges of xenotransplantation in the UK. King's College London, with endorsement from the British Transplantation Society (BTS), and the European Society of Organ Transplantation (ESOT), brought together a group of experts in xenotransplantation science, ethics and law to discuss the ethical, regulatory and technical challenges surrounding translating xenotransplantation into the clinical setting. The symposium was the first of its kind in the UK for 20 years. This paper summarises the content of the expert lectures showcasing the progress which has been made in xenotransplantation including-the history of xenotransplantation, advances in gene edited animals and progress towards clinical xenotransplantation. We then set out the ethical and legal issues still to be resolved. Finally, we report the themes of the roundtable discussion highlighting areas of consensus and controversy. While the detail of the legal discussion was directed towards the UK, the principles and summary reported here are intended to be applicable to any jurisdiction seeking to implement clinical xenotransplantation.

Research opportunities and ethical considerations for heart and lung xenotransplantation research: A report from the National Heart, Lung, and Blood Institute workshop

Xenotransplantation offers the potential to meet the critical need for heart and lung transplantation presently constrained by the current human donor organ supply. Much was learned over the past decades regarding gene editing to prevent the immune activation and inflammation that cause early organ injury, and strategies for maintenance of immunosuppression to promote longer-term xenograft survival. However, many scientific questions remain regarding further requirements for genetic modification of donor organs, appropriate contexts for xenotransplantation research (including nonhuman primates, recently deceased humans, and living human recipients), and risk of xenozoonotic disease transmission. Related ethical questions include the appropriate selection of clinical trial participants, challenges with obtaining informed consent, animal rights and welfare considerations, and cost. Research involving recently deceased humans has also emerged as a potentially novel way to understand how xeno-organs will impact the human body. Clinical xenotransplantation and research involving decedents also raise ethical questions and will require consensus regarding regulatory oversight and protocol review. These considerations and the related opportunities for xenotransplantation research were discussed in a workshop sponsored by the National Heart, Lung, and Blood Institute, and are summarized in this meeting report.

Exploring attitudes toward xenotransplantation: A scoping review of healthcare workers, healthcare students, and kidney patients

BACKGROUND

Recent advances mean that formal clinical trials of solid organ xenotransplantation are increasingly likely to begin and patients requiring a kidney transplant could be the first participants. Healthcare workers and healthcare students constitute the current and future workforce that will influence public opinion of xenotransplantation. The attitudes of these populations are important to consider before recruitment for formal clinical trials begins.

METHODS

This scoping review was reported according to the PRISMA extensions for scoping reviews checklist and the Joanna Briggs Institute methodology for scoping reviews. The Scopus, PubMed, and ScienceDirect databases were searched to identify articles that studied the attitudes of healthcare workers, healthcare students, or kidney patients toward xenotransplantation.

RESULTS

The search generated 816 articles, of which 27 met the eligibility criteria. The studies were conducted in 14 different countries on five different continents. Participants from the 27 studies totaled 29,836-this was constituted of 6,223 (21%) healthcare workers, 21,067 (71%) healthcare students, and 2,546 (8%) kidney patients. All three groups had an overall positive attitude toward xenotransplantation. However, in studies where participants were asked to consider xenotransplantation when the risks and results were not equal to allotransplantation-the overall attitude switched from positive to negative. The results also found that Spanish-speaking populations expressed more favorable views toward xenotransplantation compared to English-speaking populations.

CONCLUSION

The results of this review suggest that while attitudes of the three groups toward xenotransplantation are-on the face of it-positive, this positivity deteriorates when the risks and outcomes are framed in more clinically realistic terms. Only formal clinical trials can determine how the risks and outcomes of xenotransplantation compare to allotransplantation.

The importance of public engagement in clinical xenotransplantation

Over the past several decades, significant scientific progress in xenotransplantation has brought the field to the threshold of clinical trials. In the past 3 years in the United States, experimental pig kidney and heart xenotransplantation have been performed on human subjects recently declared dead by neurological criteria (decedents). In addition, two pig heart transplants have been carried out in living patients under the United States Food and Drug Administration's expanded access guidelines. However, though there has been a flurry of activity there remain unanswered questions regarding how the public views xenotransplantation, what concerns may exist, and how to address these concerns in a meaningful way. This paper aims to underscore the importance of public engagement in xenotransplantation, emphasizing the ongoing need for studies to assess public opinions. The current evidence on public engagement studies is reviewed and gaps in our understanding are identified. We propose practical steps to advance this field. Additional studies to determine the extent of racial/ethnic differences in attitudes to xenotransplantation should be conducted. Empirical and descriptive analysis of certain religious viewpoints-especially minority faiths-would be valuable. As public engagement is an important aspect of public acceptance of novel research that is accompanied by risk, we suggest that xenotransplantation biotechnology companies might consider leading the way in funding this research.

Evaluation of knowledge, attitude, and awareness of liver transplant patients toward xenotransplantation

BACKGROUND

Xenotransplantation (XTx) is an alternative treatment for organ scarcity. Investigating the acceptance of XTx among patients from diverse cultural and religious backgrounds is essential. This study aimed to evaluate the knowledge, attitudes, and awareness of XTx among patients undergoing liver transplant (LT).

METHODS

This descriptive study was conducted between November 2022 and August 2023. The study population comprised LT patients aged ≥18 years who were admitted to the hepatology clinic of a university hospital in Turkey. Of the 360 patients (n = 360) interviewed, 351 were deemed eligible for inclusion. A questionnaire was used to collect data. The Kolmogorov-Smirnov test, median, standard deviation, minimum-maximum, number, percentage, and Pearson's chi-square test were used for statistical analysis.

RESULTS

Of the patients, 78.3% were religious and adhered to religious requirements, and 87.2% considered their religious beliefs when making important decisions. In all, 41.3% of the participants believed that organ or tissue transplantation from animals to humans is ethical, while 70.1% of the participants believed that organ and tissue transplantation from non-halal animals to humans was impossible. Specifically, 56.7% would not allow organ or tissue transplantation from a non-halal animal to themselves or a relative. Knowledge and attitude towards XTx were not affected by transplantation type (p > .05), but were affected by sex and educational level (p < .05).

CONCLUSION

This study found that LT patients generally oppose XTx. To enhance knowledge and awareness, religious leaders and healthcare professionals should organize comprehensive and effective seminars on this topic.

Pressing ethical issues relating to clinical pig organ transplantation studies

Clinical pig heart transplant experiments have been undertaken, and further clinical experiments and/or clinical trials of gene-edited pig organ xenotransplantation are anticipated. The ethical issues relating to xenotransplantation have been discussed for decades but with little resolution. Consideration of certain ethical issues is more urgent than others, and the need to attain consensus is important. These issues include: (i) patient selection criteria for expanded access and/or clinical trials; (ii) appropriate protection of the patient from xenozoonoses, that is, infections caused by pig microorganisms transferred with the organ graft, (iii) minimization of the risk of a xenozoonosis to bystanders, and (iv) the need for additional public perception studies. We discuss why it is important and urgent to achieve consensus on these ethical issues prior to carrying out further expanded access experiments or initiating formal clinical trials. The ways forward on each issue are proposed.

Attitudes of patients with renal disease on xenotransplantation: A systematic review

BACKGROUND

Recent years have seen major advancements in xenotransplantation: the first pig-to-human heart transplant, the development of a brain-dead recipient model for kidney xenotransplantation, and the registration of the first xenokidney clinical trial. The attitudes of patients with kidney disease or transplants on xenotransplantation and an assessment of their reservations and considerations regarding the technology are crucial to successful clinical translation and eventual widespread implementation.

METHODS

This systematic review was registered through PROSPERO (CRD42022344581) prior to initiation of the study and reported using the Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) guidelines. We included studies that evaluated attitudes towards and willingness to undergo xenotransplantation in patients with end-stage renal disease (ESRD), including those who had already undergone transplantation. MEDLINE (via Ovid), Embase (via Elsevier), and Web of Science (via Clarivate) were searched from database inception to July 15, 2022 by an experienced medical librarian for studies on xenotransplantation and attitudes. Abstracts and full text were screened using Covidence software and data items regarding study methodology, patient demographics, and attitudes regarding xenotransplantation were extracted using Microsoft Excel. Risk of bias assessments were performed using the Critical Appraisal Skills Programmed and National Institute of Health study quality assessment tools.

RESULTS

Of 1992 studies identified, 14 studies met the inclusion criteria. These studies were conducted across eight countries, four in the United States, for a total of 3114 patients on the kidney waitlist or with a kidney transplant. All patients were over 17 years old and 58% were male. Acceptance of a xenotransplant was assessed using surveys in 12 studies. Sixty-three percent (n = 1354) of kidney patients reported that they would accept a xenotransplant with function comparable to that of an allotransplant. Acceptance of xenografts with inferior function to allografts (15%) or as bridge organs (35%) to allotransplantation was lower. Specific concerns expressed by patients included graft function, infection, social stigma, and animal rights. Subgroup analyses showed higher acceptance in already transplanted compared to waitlist patients and white compared to Black Americans.

CONCLUSION

An understanding of patient attitudes and reservations is key to the successful execution of the first xenotransplantation clinical trials. This study compiles important factors to consider, such as patient concerns, attitudes regarding practical clinical scenarios for the use of xenotransplantation, and the impact of demographic factors on acceptance of this emerging technology.

Practical ethical concerns in allocation of pig kidneys to humans

The fundamental ethical question of whether pig organs should be transplanted into humans has been settled, as recent surgeries demonstrating proof of concept demonstrate. Other issues need to be considered and reconciled before xenotransplantation of pig kidneys becomes a solution to the organ shortage for people waiting for a kidney transplant or as a viable alternative to the deceased donor or living donor human kidneys. Human trials will be needed beyond brain-dead individuals to show that xenotransplantation is safe from immunologic and infectious standpoints. Transplant centers will need to show that xenotransplantation provides a long-term benefit to recipients and is financially viable. If trials are successful and receive regulatory approval, pig xenotransplants may become another option for people waiting for a kidney. Before patients are discharged with a functioning xenograft, practical issues with ethical implications remain.

Informed Consent for Potential Recipients of Pig Kidney Xenotransplantation in the United States

Clinical trials of kidney xenotransplantation are being considered in the United States. Before this novel procedure can take place, investigators will have to obtain approval from the institutional review board. The consent form that will be used for such a trial and that will receive approval from the institutional review board will be complex. Informed consent-the process by which a research participant provides his/her permission to participate in a clinical trial-is a staple of the research process and most commonly is in the form of a physical document. In the case of a novel procedure with uncertain benefits and risks and a participant population in acute need of a transplant, the consent process is crucial. These complexities may raise several ethical considerations for the initial pig kidney xenotransplantation recipients in the United States that will require adaptations of the required elements of the informed consent process by the US Department of Human and Health Services. The ethical issues include (1) a subject's ability to withdraw from the trial, (2) restrictions on their reproductive rights, and (3) the possibility of the need for quarantine if there is a perceived risk of xenozoonosis. This article aims to discuss ethical considerations that may challenge the general required elements of the informed consent form stipulated by the 45 Code of Federal Regulations 46 of the US Department of Health and Human Services and to suggest recommendations for deliberation.

The potential of genetically engineered pig heart transplantation in infants with complex congenital heart disease

Despite advances in surgical and medical techniques, complex congenital heart disease in neonates and infants continues to be associated with significant mortality and morbidity. More than 500 infants in the USA are placed on the cardiac transplantation wait-list annually. However, there remains a critical shortage of deceased human donor organs for transplantation with a median wait-time of 4 months. Hence, infant mortality on the heart transplant wait-list in the USA is higher than for any other solid organ transplant group. Orthotopic transplantation of a pig heart as a bridge to allotransplantation might offer the best prospect of long-term survival of these patients. In recent years, there have been several advances in genetic engineering of pigs to mitigate the vigorous antibody-mediated rejection of a pig heart transplanted into a nonhuman primate. In this review, we briefly highlight (i) the history of clinical heart xenotransplantation, (ii) current advances and techniques of genetically engineering pigs, (iii) the current status of pig orthotopic cardiac graft survival in nonhuman primates, and (iv) progress toward pursuing clinical trials of cardiac xenotransplantation. Ultimately, we argue that pig heart xenotransplantation should initially be used as a bridge to cardiac allotransplantation in neonates and infants.

Genetically engineered pig kidney transplantation in a brain-dead human subject

In September 2021, a kidney (with donor-specific thymic tissue) from an α1, 3-galactosyltransferase gene-knockout (GTKO) pig was transplanted into the groin (with anastomoses to the femoral vessels) of a brain-dead subject by a surgical team at New York University Langone Health (NYU). It was reported to function immediately, passing urine and excreting creatinine. The experiment was terminated after 54 h and, during this period, the kidney did not show macroscopic features of rejection. Does this experiment provide information not available to us previously and does it move the field forward to clinical trials? The information provided was very limited, but the following points are worthy of note. (i) Numerous in vivo studies in nonhuman primates have predicted that the pig kidney would function immediately. (ii) Numerous in vitro studies have predicted that a GTKO pig kidney would not be rejected within the first few days after transplantation into a human subject. (iii) GTKO kidneys are not optimal for clinical transplantation, and the transplantation of a triple-knockout (TKO) pig kidney would have been more relevant. (iv) There was no purpose in transplanting a "thymokidney" without pre-transplant conditioning therapy and follow-up for several months. (v) Because the native kidneys were retained, it is difficult to determine whether the function of the graft was sufficient to support life. (vi) The experiment was announced to the media rather than published in a peer-reviewed medical journal (although hopefully this will follow), suggesting that it was primarily carried out to gain attention to the great potential of xenotransplantation (and/or possibly to NYU). In this respect the experiment was successful. Because of the very limited period of time for which a brain-dead subject can be maintained in a metabolically and hemodynamically stable state, the value of experiments in such subjects will remain very limited. It is hoped that any future similar experiments will be planned to be more relevant to the clinical situation. Nevertheless, the report has stimulated public attention towards xenotransplantation which, unless there is an adverse response to what some might consider to be a bizarre experiment, should be of significant benefit to future progress.

"You cannot stay in the laboratory forever"*: Taking pig kidney xenotransplantation from the laboratory to the clinic

Progress in life-supporting kidney transplantation in the genetically-engineered pig-to-nonhuman primate model has been encouraging, with pig kidneys sometimes supporting life for > 1 year. What steps need to be taken by (i) the laboratory team, and (ii) the clinical team to prepare for the first clinical trial? The major topics include (i) what currently-available genetic modifications are optimal to reduce the possibility of graft rejection, (ii) what immunosuppressive therapeutic regimen is optimal, and (iii) what steps need to be taken to minimize the risk of transfer of an infectious microorganism with the graft. We suggest that patients who are unlikely to live long enough to receive a kidney from a deceased human donor would benefit from the opportunity of a period of dialysis-free support by a pig kidney, and the experience gained would enable xenotransplantation to progress much more rapidly than if we remain in the laboratory.

Don't pig(!) the wrong heart!

Cardiac xenotransplantation is believed to have approached clinical application. However, this approach to advanced heart failure is burdened with a multitude of ethical issues. These issues need to be addressed openly and be broadly discussed in public. Only through an honest and transparent approach, it will be possible to engage the lay audience in the evaluation of pig to human transplant.