A standardised and reproducible method for en bloc multi-visceral organ retrieval in a porcine model – Barnett

The New Frontier of Organ Preservation: From Static Storage to Active Repair

For decades, the gold standard for organ transplantation has been a race against the clock. Once an organ is retrieved, the focus is on “stopping the clock” through cold storage, hoping the organ remains viable until it reaches the recipient. However, the landscape is shifting toward a more proactive approach: ex vivo perfusion, and resuscitation.

The goal is no longer just to preserve, but to assess and repair. By keeping organs metabolically active outside the body, surgeons can test viability in real-time, ensuring that only the healthiest grafts are transplanted. This shift is critical because the gap between organ supply and demand remains a crisis; in 2024, 31,853 patients died while remaining on the transplant waitlist.

Expanding the Donor Pool: The Rise of Marginal Organs

To address the chronic shortage of organs, the medical community is looking toward “marginal” organs—those from expanded criteria donors (ECD) or donation after circulatory death (DCD). Traditionally, these organs carry a higher risk of early graft failure.

The future lies in Normothermic Regional Perfusion (NRP) and Dual-Hypothermic Oxygenated Perfusion (D-HOPE). These technologies allow clinicians to mitigate the effects of ischemia (lack of blood flow) and potentially “rescue” organs that would have previously been discarded. By moving from controlled to uncontrolled donation models, the medical field can significantly increase the number of usable organs available for patients.

The Concept of Organ Assessment and Reconditioning Centres (ARCs)

Imagine a future where organs aren’t shipped directly from donor to recipient, but instead pass through a specialized “capacitor” center. These proposed ARCs would store and recondition organs ex vivo, releasing them to recipient centers only after their viability is confirmed.

One of the most efficient ways to achieve this is through en bloc retrieval—removing a composite block of organs (such as the liver, pancreas, kidneys, and small bowel) together. This reduces the need for multiple individual perfusion machines and consumables, streamlining the process of maintaining several organs from a single donor simultaneously.

Bridging the Gap: Why Porcine Models are Essential

Before a new preservation technique reaches a human operating theater, it must be proven in a model that mimics human anatomy and physiology. This is where the porcine (pig) model becomes indispensable. Because pigs have a well-characterized major histocompatibility system and a modifiable genome, they serve as the perfect bridge for “bench-to-bedside” research.

Recent advancements in surgical techniques now allow for the safe, reproducible retrieval of a multi-visceral organ block in pigs. This enables researchers to evaluate intact physiological axes—such as the glucose-insulin axis and GLP-1 production—during ex vivo perfusion. This level of functional testing is impossible with single-organ models and is essential for defining the “point of no return” for damaged organs.

The Challenge of the Small Bowel

The small bowel is notoriously immunogenic, making it one of the most difficult organs to transplant successfully. Future trends are focusing on ex vivo graft modification, such as the targeted depletion of gut-associated lymphocytes, to improve immunological outcomes. Large animal models allow scientists to test these customized immunosuppression protocols in a setting that closely replicates the clinical environment of a brain-dead donor.

The Economics of Innovation

Translational research is a high-investment endeavor. For example, a single operation for multi-visceral retrieval in a porcine model can cost approximately $4,692.28 USD. This includes animal procurement, husbandry, and high-cost surgical disposables like ultrasonic dissectors and endoscopic staplers.

While expensive, these costs are a fraction of the long-term societal and medical cost of organ failure and the limitations of current waitlist systems. The investment in these models is what allows the transition from “nebulous criteria” for organ acceptance to precise, data-driven viability markers.

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