Mechanisms of resistance to oncogenic KRAS inhibition in pancreatic cancer.

KRAS inhibitors demonstrate clinical efficacy in pancreatic ductal adenocarcinoma (PDAC); however, resistance is common. Among patients with KRASG12C-mutant PDAC treated with adagrasib or sotorasib, mutations in PIK3CA and KRAS, and amplifications of KRASG12C, MYC, MET, EGFR, and CDK6 emerged at acquired resistance. In PDAC cell lines and organoid models treated with the KRASG12D inhibitor MRTX1133, epithelial-to-mesenchymal transition and PI3K-AKT-mTOR signaling associate with resistance to therapy. MRTX1133 treatment of the KrasLSL-G12D/+;Trp53LSL-R172H/+;p48-Cre (KPC) mouse model yielded deep tumor regressions, but drug resistance ultimately emerged, accompanied by amplifications of Kras, Yap1, Myc, and Cdk6/Abcb1a/b, and co-evolution of drug-resistant transcriptional programs. Moreover, in KPC and PDX models, mesenchymal and basal-like cell states displayed increased response to KRAS inhibition compared to the classical state. Combination treatment with KRASG12D inhibition and chemotherapy significantly improved tumor control in PDAC mouse models. Collectively, these data elucidate co-evolving resistance mechanisms to KRAS inhibition and support multiple combination therapy strategies.

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.

Knowledge gaps in heart and lung donation after the circulatory determination of death: Report of a workshop of the National Heart, Lung, and Blood Institute.

In a workshop sponsored by the U.S. National Heart, Lung, and Blood Institute, experts identified current knowledge gaps and research opportunities in the scientific, conceptual, and ethical understanding of organ donation after the circulatory determination of death and its technologies. To minimize organ injury from warm ischemia and produce better recipient outcomes, innovative techniques to perfuse and oxygenate organs postmortem in situ, such as thoracoabdominal normothermic regional perfusion, are being implemented in several medical centers in the US and elsewhere. These technologies have improved organ outcomes but have raised ethical and legal questions. Re-establishing donor circulation postmortem can be viewed as invalidating the condition of permanent cessation of circulation on which the earlier death determination was made and clamping arch vessels to exclude brain circulation can be viewed as inducing brain death. Alternatively, TA-NRP can be viewed as localized in-situ organ perfusion, not whole-body resuscitation, that does not invalidate death determination. Further scientific, conceptual, and ethical studies, such as those identified in this workshop, can inform and help resolve controversies raised by this practice.

The American Society of Transplant Surgeons Consensus Statement on Normothermic Regional Perfusion.

On June 3, 2023, the American Society of Transplant Surgeons convened a meeting in San Diego, California to (1) develop a consensus statement with supporting data on the ethical tenets of thoracoabdominal normothermic regional perfusion (NRP) and abdominal NRP; (2) provide guidelines for the standards of practice that should govern thoracoabdominal NRP and abdominal NRP; and (3) develop and implement a central database for the collection of NRP donor and recipient data in the United States. National and international leaders in the fields of neuroscience, transplantation, critical care, NRP, Organ Procurement Organizations, transplant centers, and donor families participated. The conference was designed to focus on the controversial issues of neurological flow and function in donation after circulatory death donors during NRP and propose technical standards necessary to ensure that this procedure is performed safely and effectively. This article discusses major topics and conclusions addressed at the meeting.

Researching COVID to enhance recovery (RECOVER) tissue pathology study protocol: Rationale, objectives, and design.

IMPORTANCE: SARS-CoV-2 infection can result in ongoing, relapsing, or new symptoms or organ dysfunction after the acute phase of infection, termed Post-Acute Sequelae of SARS-CoV-2 (PASC), or long COVID. The characteristics, prevalence, trajectory and mechanisms of PASC are poorly understood. The objectives of the Researching COVID to Enhance Recovery (RECOVER) tissue pathology study (RECOVER-Pathology) are to: (1) characterize prevalence and types of organ injury/disease and pathology occurring with PASC; (2) characterize the association of pathologic findings with clinical and other characteristics; (3) define the pathophysiology and mechanisms of PASC, and possible mediation via viral persistence; and (4) establish a post-mortem tissue biobank and post-mortem brain imaging biorepository. METHODS: RECOVER-Pathology is a cross-sectional study of decedents dying at least 15 days following initial SARS-CoV-2 infection. Eligible decedents must meet WHO criteria for suspected, probable, or confirmed infection and must be aged 18 years or more at the time of death. Enrollment occurs at 7 sites in four U.S. states and Washington, DC. Comprehensive autopsies are conducted according to a standardized protocol within 24 hours of death; tissue samples are sent to the PASC Biorepository for later analyses. Data on clinical history are collected from the medical records and/or next of kin. The primary study outcomes include an array of pathologic features organized by organ system. Causal inference methods will be employed to investigate associations between risk factors and pathologic outcomes. DISCUSSION: RECOVER-Pathology is the largest autopsy study addressing PASC among US adults. Results of this study are intended to elucidate mechanisms of organ injury and disease and enhance our understanding of the pathophysiology of PASC.

Revisiting the Use of Ulysses Contracts in Xenotransplantation.

BACKGROUND: Xenotransplantation clinical trials may begin soon. A persistent risk of xenotransplantation, known for decades, is the possibility that a xenozoonotic infection could be transferred from a xenograft to its recipient and then to other human contacts. Because of this risk, guidelines and commentators have advocated for xenograft recipients to agree to either long-term or lifelong surveillance mechanisms. METHODS: For the past few decades, one solution that has been proposed to ensure that xenograft recipients will comply with surveillance protocols is the use of a heavily modified Ulysses contract, which we review. RESULTS: These contracts are most often used in psychiatry, and their application to xenotransplantation has been espoused several times with minimal criticism. CONCLUSIONS: In this article, we argue against the applicability of Ulysses contracts in xenotransplantation based upon (1) the telos of the advance directive that may not be applicable to this clinical context, (2) the suspect nature of enforcing Ulysses contracts in xenotransplantation, and (3) the ethical and regulatory hurdles that such enforcement would require. Although our focus is on the US regulatory landscape in preparation for clinical trials, there are applications globally.

Research involving the recently deceased: ethics questions that must be answered.

Research involving recently deceased humans that are physiologically maintained following declaration of death by neurologic criteria-or 'research involving the recently deceased'-can fill a translational research gap while reducing harm to animals and living human subjects. It also creates new challenges for honouring the donor's legacy, respecting the rights of donor loved ones, resource allocation and public health. As this research model gains traction, new empirical ethics questions must be answered to preserve public trust in all forms of tissue donation and in the practice of medicine while respecting the legacy of the deceased and the rights of donor loved ones. This article suggests several topics for immediate investigation to understand the attitudes and experiences of researchers, clinical collaborators, donor loved ones and the public to ensure research involving the recently deceased advances ethically.

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.

Challenges Unique to Transgender Persons in US Correctional Settings: a Scoping Review.

US correctional facilities operate under a binary interpretation of gender, which can yield inherent risks and conflicts for incarcerated transgender people. We conducted a scoping literature review on challenges unique to transgender individuals within US correctional settings. Online databases were searched to identify papers that addressed the challenges of incarcerated transgender adults age 18 + within US correctional institutions. A concurrent analysis of legal literature was reviewed with key policy recommendations extracted. A total of 33 papers (21 scientific studies and 12 legal analyses) met criteria for inclusion. Of the 21 scientific studies, the majority of papers (n = 14) focused on transgender women and most (n = 13) utilized qualitative methods. Emerging themes revealed challenges in key domains of violence, health, healthcare access, housing, and a pervasive culture of transphobia. Legal analyses supported policy changes such as implementing case-by-case housing classification systems, providing all forms of gender-affirming care, and safeguarding gender expression. Transgender persons face distinct obstacles while incarcerated in US correctional facilities and are in need of expanded protections. Working in tandem with efforts to decarcerate and reduce criminal legal involvement, widespread institutional policy change, such as redefining housing assignment policies, ensuring gender-affirming healthcare, and expanding transgender-specific competency trainings for correctional staff, is necessary.

Examining the Ethics and Impacts of Laws Restricting Transgender Youth-Athlete Participation.

As of this writing, twenty-one states have passed laws barring transgender youth-athletes from competing on public-school sports teams in accordance with their gender identity. Proponents of these regulations claim that transgender females in particular have inherent physiological advantages that threaten a "level playing field" for their cisgender competitors. Existing evidence is limited but does not support these restrictions. Gathering more robust data will require allowing transgender youth to compete (rather than preemptively barring them), but even if trans females are shown to retain some advantage, this would not have greater moral significance than the many other "fair" physical and economic advantages found across sports. These regulations deprive transgender youth, an exceptionally vulnerable population, from the vast physical, mental, and social benefits of sports. While we advocate for transgender inclusion under our current, gender-segregated model of sport, we propose changes to the overarching structure that would promote a more inclusive and fairer athletic environment.

Thoracoabdominal normothermic regional perfusion in donation after circulatory death does not restore brain blood flow.

Use of thoracoabdominal normothermic regional perfusion (TA-NRP) during donation after circulatory death (DCD) is an important advance in organ donation. Prior to establishing TA-NRP, the brachiocephalic, left carotid, and left subclavian arteries are ligated, thereby eliminating anterograde brain blood flow via the carotid and vertebral arteries. While theoretical concerns have been voiced that TA-NRP after DCD may restore brain blood flow via collaterals, there have been no studies to confirm or refute this possibility. We evaluated brain blood flow using intraoperative transcranial Doppler (TCD) in two DCD TA-NRP cases. Pre-extubation, anterior and posterior circulation brain blood flow waveforms were present in both cases, similar to the waveforms detected in a control patient on mechanical circulatory support undergoing cardiothoracic surgery. Following declaration of death and initiation of TA-NRP, no brain blood flow was detected in either case. Additionally, there was absence of brainstem reflexes, no response to noxious stimuli and no respiratory effort. These TCD results demonstrate that DCD with TA-NRP did not restore brain blood flow.

Extracorporeal cardiopulmonary resuscitation dissemination and integration with organ preservation in the USA: ethical and logistical considerations.

Use of extracorporeal membrane oxygenation (ECMO) in cardiopulmonary resuscitation, termed eCPR, offers the prospect of improving survival with good neurological function after cardiac arrest. After death, ECMO can also be used for enhanced preservation of abdominal and thoracic organs, designated normothermic regional perfusion (NRP), before organ recovery for transplantation. To optimize resuscitation and transplantation outcomes, healthcare networks in Portugal and Italy have developed cardiac arrest protocols that integrate use of eCPR with NRP. Similar dissemination of eCPR and its integration with NRP in the USA raise novel ethical issues due to a non-nationalized health system and an opt-in framework for organ donation, as well as other legal and cultural factors. Nonetheless, eCPR investigations are ongoing, and both eCPR and NRP are selectively employed in clinical practice. This paper delineates the most pressing relevant ethical considerations and proposes recommendations for implementation of protocols that aim to promote public trust and reduce conflicts of interest. Transparent policies should rely on protocols that separate lifesaving from organ preservation considerations; robust, centralized eCPR data to inform equitable and evidence-based allocations; uniform practices concerning clinical decision-making and resource utilization; and partnership with community stakeholders, allowing patients to make decisions about emergency care that align with their values. Proactively addressing these ethical and logistical challenges could enable eCPR dissemination and integration with NRP protocols in the USA, with the potential to maximize lives saved through both improved resuscitation with good neurological outcomes and increased organ donation opportunities when resuscitation is unsuccessful or not in accordance with individuals' wishes.

Unique problems for the design of the first trials of transplanting porcine kidneys into humans.

Over the past year, 3 scientific teams conducted experiments of genetically edited porcine organs into human recipients, 3 of whom were deceased and 1 living. In this editorial, we describe challenges for the design of initial xenotransplantation clinical trials and focus on patient selection, consent, and requisite post-transplant follow-up. Given the uncertain clinical benefit of xenotransplantation, we propose that patient selection criteria might include novel elements, such as approaching patients who have a low quality of life and a strong aversion to continued dialysis therapy. We set expectations related to the importance of informing and protecting family members and medical teams who could be exposed to zoonotic viral infection from the donor organ and/or receive unwanted publicity. Meeting these challenges in trial design and oversight will require multidisciplinary expertise, a conceptual model that extends beyond the individual patient, and creative collaboration between scientists and regulatory agencies.

Human, Nonhuman, and Chimeric Research: Considering Old Issues with New Research.

Human-nonhuman chimeric research-research on nonhuman animals who contain human cells-is being used to understand human disease and development and to create potential human treatments such as transplantable organs. A proposed advantage of chimeric models is that they can approximate human biology and therefore allow scientists to learn about and improve human health without risking harms to humans. Among the emerging ethical issues being explored is the question of at what point chimeras are "human enough" to have human rights and thus be owed higher standards of research protection than that currently afforded to nonhuman animals. However, this question and other related questions assume that the ethics of experimenting on nonhuman animals have been settled, which they have not. In this essay, we argue that it is imperative to give adequate attention to familiar questions about nonhuman animal research as well as new questions about chimera research and that failure to do so will result in a distorted understanding of the ethics of chimera research.

Clarifying the Ethics and Oversight of Chimeric Research.

This article is the lead piece in a special report that presents the results of a bioethical investigation into chimeric research, which involves the insertion of human cells into nonhuman animals and nonhuman animal embryos, including into their brains. Rapid scientific developments in this field may advance knowledge and could lead to new therapies for humans. They also reveal the conceptual, ethical, and procedural limitations of existing ethics guidance for human-nonhuman chimeric research. Led by bioethics researchers working closely with an interdisciplinary work group, the investigation focused on generating conceptual clarity and identifying improvements to governance approaches, with the goal of helping scholars, funders, scientists, institutional leaders, and oversight bodies (embryonic stem cell research oversight [ESCRO] committees and institutional animal care and use committees [IACUCs]) deliver principled and trustworthy oversight of this area of science. The article, which focuses on human-nonhuman animal chimeric research that is stem cell based, identifies key ethical issues in and offers ten recommendations regarding the ethics and oversight of this research. Turning from bioethics' previous focus on human-centered questions about the ethics of "humanization" and this research's potential impact on concepts like human dignity, this article emphasizes the importance of nonhuman animal welfare concerns in chimeric research and argues for less-siloed governance and oversight and more-comprehensive public communication.