Faculty Bibliography

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: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.).

Donation after circulatory determination of death (DCDD) has increased organ donation rates in the US over the past decade within an established legal framework, which is consistent with and supports individual and family decisions regarding organ donation in the context of end-of-life care. A new application, controlled DCDD donation utilizing thoracoabdominal normothermic regional perfusion (NRP) protocols (cDCDD-NRP), provides the opportunity to maximize a donation decision by recovering additional organs for transplant, including the heart, and to limit the detrimental impact of warm ischemic time by perfusing organs in situ following the declaration of circulatory death. In this viewpoint, we narrate our rationale for why cDCDD-NRP is consistent within the existing legal framework for organ donation in the United States and recommend no changes to the Uniform Determination of Death Act.

This paper responds to the position statement released by the American College of Physicians (ACP) entitled "Ethics, Determination of Death, and Organ Transplantation in Normothermic Regional Perfusion (NRP) with Controlled Donation after Circulatory Determination of Death (cDCD): American College of Physicians Statement of Concern." The ACP's statement engages with critical ethical issues surrounding cDCD NRP, but several of their conclusions are flawed. Contrary to the statement, the practice respects the dead donor rule and the legal definition of death while honoring the wishes of the deceased and their loved ones to help save the lives of those in need of organ transplants. cDCD NRP is well established in many countries, it can enhance trust in medical practice and organ donation, and will increase the availability of optimal organs for life-saving transplants.

Innovative research in deceased donation and transplantation often presents ethical challenges for researchers and those responsible for ethical governance of research. These challenges have been recognized as potential barriers to the conduct of research. We review the literature to identify and describe ethical considerations that may cause confusion or uncertainty in the context of research involving potential deceased donors or deceased donor transplantation. We normatively examine these considerations and discuss their implications for the ethical conduct of research. In addition to the complexities of research involving critically ill, dying or recently deceased individuals, uncertainty may arise regarding the ethical status of various individuals who may be involved in research aimed at improving availability and outcomes of organ transplantation. Consequently, routine ethical guidelines for clinical research may fail to provide clear guidance with regards to the design, conduct and governance of some deceased donation or transplantation studies. Ethical uncertainty may result in delays or barriers to research, or neglect of important ethical considerations. Specific ethical guidance is needed to support research in deceased donation and transplantation as the ethical considerations that arise in the design and conduct of such research may not be addressed in the existing guidelines for human research.

Solid organ transplant (SOT) candidates and recipients were not included in the COVID-19 vaccine trials that have justified vaccine administration to millions worldwide and will be critical to ending the pandemic. The risks of COVID-19 for SOT candidates and recipients combined with data about this population's response to other vaccines has led to transplant centers recommending vaccination for their candidates and recipients in accordance with guidance from major transplant organizations. Relevant ethics considerations include: weighing the low risk of vaccination causing transplant complications against potentially limited antibody response of vaccines for transplant recipients; the equitable distribution of vaccines among vulnerable populations; the duty to steward and respect organs as limited resources; the duty to support vaccination; and patient autonomy. Vaccinated transplant patients and candidates should also consider participating in research studies to better understand the efficacy and potential long-term risks in this patient population. There are difficult scenarios, like timing transplant after second vaccine dose, when to administer the second dose to a partially vaccinated candidate who gets an organ match, whether to vaccinate a recent transplant recipient with low exposure risk and which vaccine to use. Here we provide ethics considerations for vaccinating different groups within the transplant population.