Xenotransplantation and the Future of Organ Supply: A Case for Human-Derived Alternatives
By CriShaun Hardy| March 26th, 2026
With the persistence of a global shortage of transplantable human organs, xenotransplantation has been proposed as a potential response, allowing for the creation of a number of permanent or temporary organs for use in human patients. Since earlier policy discussions first examined xenotransplantation’s potential and risks, the field has progressed from isolated experimental procedures into early clinical trials. However, xenotransplantation is not the only scientific pathway being explored to address organ scarcity and perhaps should not be society’s first choice.
Another emerging area of research has focused on organoid technologies and the potential for organs to be synthesized in a lab setting, using human cells. Organoids are three-dimensional cellular structures derived from human stem cells that self-organize to mimic key structural and functional features of human organs. Currently, organoid systems are being used in disease modeling, toxicology, and regenerative medicine.
This blogpost examines key developments that have emerged in xenotransplantation and highlights lab-grown organs as an alternative, and potentially complementary, pathway. Organs developed from human stem cells have the potential to avoid many of the risks of xenotransplantation, by offering pathways toward compatible patient-specific organs in a manner that reduces reliance on animal sources while avoiding the ethical challenges inherent to xenotransplantation.
The State of Xenotransplantation
Advances in genetic engineering have been central to the progress of xenotransplantation, shifting the science from merely placing unaltered animal organs into human recipients to the targeted modification of donor animal organs, which reduce the likelihood of immunological rejection. While full-scale clinical application is likely several years away, closely monitored clinical trials overseen by the Food and Drug Administration (FDA) are currently being conducted using genetically modified pig kidneys and livers. These trials represent an important proof of concept, potentially demonstrating that modified animal organs can function, at least temporarily, in human recipients. In the short term, such interventions may allow recipients to survive for longer periods while awaiting an organ from a viable human donor or, if further advances can fully address rejection, eliminate the need to rely on human donors entirely.
With these clinical trials underway and the results still pending, outcomes from earlier compassionate-use procedures serve to demonstrate the experimental nature of xenotransplantation. Although some of the previously transplanted organs have demonstrated short-term function, long-term patient survival has not been observed beyond a few months. Ultimately, immunological rejection remains the central challenge to long-term patient survival.
In addition to these biological hurdles, xenotransplantation raises significant regulatory and ethical questions surrounding what a full-scale industry would look like. This uncertainty is especially apparent amid a broader global shift away from animal testing and the increasing scrutiny of animal use in biomedical research. Scaling xenotransplantation would require the breeding, genetic modification, and long-term management of animals specifically for organ procurement, raising concerns as to animal welfare, biosecurity, and regulatory oversight. Regulatory frameworks would also need to address the long-term monitoring of recipients, containment of potential zoonotic risks, and the allocation of resources for this highly specialized area of science.
Taken together, the scientific, regulatory, and ethical constraints suggest that while xenotransplantation has made meaningful progress, its role in addressing organ scarcity may remain limited in scope for the near future, prompting the need for continued exploration of alternative or complementary approaches.
The Potential of Lab-Grown Organs and Organoids
In contrast to xenotransplantation, lab-grown organs and organoid technologies may address the scarcity issue by relying largely on human cells rather than animal sources. These approaches involve a range of strategies, including stem cell-derived organoids and tissue scaffolding. While these technologies are not yet capable of producing fully transplantable organs, recent advances have expanded their scientific relevance and offer a glimpse into a future where such organs will be available.
Organoids, for example, have emerged as a foundational platform in this broader effort towards more human-relevant biomedical research. Derived from human stem cells, organoids self-organize into structures that can reproduce key aspects of human organ formation and function. To date, organoids representing a variety of tissues, including liver, kidney, heart, and brain, have been developed and are widely used in biomedical research. Their ability to model human-specific biology has made them valuable tools for studying disease mechanisms, evaluating drug toxicity, and exploring regenerative processes that are otherwise difficult to replicate in animal models.
From a transplantation perspective, the most significant potential advantage of lab-grown organs is their compatibility with human immune systems. Because these tissues can, in principle, be derived from a patient’s own cells or from immunologically matched human sources, they may reduce or eliminate the risk of rejection that remains a central hurdle to xenotransplantation. At the same time, the use of human-derived cells avoids many of the ethical concerns associated with sourcing organs from animals, including issues related to animal welfare and cross-species disease transmission.
Despite these potential benefits, the clinical application of lab-grown organs still faces its own scientific and regulatory challenges. For example, achieving the necessary sufficient size and vascularization for lab organs remains a significant barrier, especially for complex organs like the heart and liver. In addition, translating organoid and tissue-engineering technologies from research settings into standardized and safe clinical products raises unresolved regulatory questions, including how such products should be classified and monitored by agencies like the FDA.
Ultimately, lab-grown organs and organoids technologies represent a promising but still emerging pathway for addressing organ scarcity. While not necessarily an immediate replacement for traditional organ donation, with the proper resource allocation, these approaches may reshape how transplantation medicine considers organ sourcing, compatibility, and ethical scaling.
Conclusion
In the end, efforts to address the shortage of transplantable organs will likely be shaped by the pursuit of multiple scientific pathways. For policymakers and regulators, these developments illustrate the increasingly complex landscape for the future of transplant policy. Rather than converging on a single solution, emerging technologies are expanding the regulatory questions surrounding safety, oversight, and ethical acceptability. As the science behind transplantation continues to evolve, careful and sustained policy engagement will be needed to ensure that regulatory frameworks remain responsive to innovation while addressing the demands of public health. Advancing the development and use of lab grown organs should be a major part of this discussion because of the promise it holds for addressing this difficult challenge
Sources:
Xenotransplantation experiments in brain-dead human subjects-A critical appraisal
Organoids: A new window into disease, development and discovery
Scientists Take First Steps Toward Growing Organs from Scratch
Lo and Behold, the Lab-Grown Organs Have Arrived!
Human organoids in basic research and clinical applications
Organoids: Expanding Applications Enabled by Emerging Technologies
Organoids: The current status and biomedical applications
Organoids in Tissue Transplantation
The views expressed do not necessarily reflect the official policy or position of Johns Hopkins University or Johns Hopkins Bloomberg School of Public Health.
