Organ Preservation and Reperfusion Injury
Organ preservation is the set of techniques that keep a donor organ viable between procurement and implantation, and reperfusion injury is the paradoxical tissue damage that can occur when blood flow is restored to that organ. Together they define a central problem of transplantation surgery: an organ must survive a period without normal circulation, and the period of ischemia plus the act of reperfusion jointly determine how well the graft will work afterwards.
Definition
Organ preservation comprises the methods used to maintain the viability of an organ removed from a donor until it is transplanted into a recipient; reperfusion injury is the cellular and microvascular damage triggered when oxygenated blood is reintroduced to tissue that has been ischemic.
Scope
This area orients the reader to how organs are kept and reperfused rather than to the surgical anastomosis itself. It groups the preservation modalities (cold static storage and the spectrum of machine perfusion), the underlying injury process (ischemia-reperfusion injury), and the clinical states that follow when preservation and reperfusion fall short (delayed graft function and primary nonfunction). It is a reference overview; the detailed essentials live in the topic entries below.
Sub-topics
Core questions
- How can a procured organ be kept viable during the interval between donor and recipient?
- Why does restoring blood flow itself cause injury, and not only the preceding ischemia?
- How do preservation choices and ischemic times translate into graft function or failure after transplantation?
Key concepts
- Cold ischemia time
- Warm ischemia time
- Static cold storage
- Machine perfusion (hypothermic and normothermic)
- Ischemia-reperfusion injury
- Delayed graft function
- Primary nonfunction
- Donation after circulatory death versus brain death
Mechanisms
Hypothermia slows metabolism and the depletion of cellular energy stores, which is why cold storage in specialized preservation solutions became the foundation of organ preservation (Southard & Belzer, 1989). During ischemia, oxygen and substrate deprivation derange cellular ion handling and energy metabolism; on reperfusion, the abrupt return of oxygen drives a burst of reactive oxygen species, complement and innate-immune activation, and microvascular dysfunction that can extend rather than relieve the injury (Eltzschig & Eckle, 2011). Machine perfusion seeks to limit this cascade by maintaining flow through the organ during storage, either cold (hypothermic) or at near-physiologic temperature (normothermic), and has been tested against conventional cold storage in randomized trials (Moers et al., 2009; Nasralla et al., 2018).
Clinical relevance
Preservation strategy and ischemic times are among the modifiable determinants of how a transplanted organ behaves, so they bear on graft and recipient outcomes across kidney, liver, heart, and lung transplantation. This entry describes the concepts and the evidence base; it is not a protocol and does not direct device selection, solution choice, or individual patient management.
Evidence & guidelines
Randomized trials have compared machine perfusion with static cold storage, including hypothermic machine perfusion in deceased-donor kidney transplantation (Moers et al., 2009) and normothermic machine perfusion in liver transplantation (Nasralla et al., 2018). The mechanistic literature on ischemia-reperfusion injury connects these clinical findings to a shared biology (Eltzschig & Eckle, 2011). Definitions of the downstream clinical states are treated in the topic entries.
History
Practical organ preservation began with simple cold flushing and storage; the introduction of the University of Wisconsin solution made longer cold storage of abdominal organs routine and reshaped transplant logistics (Southard & Belzer, 1989). As donor pools widened to include more marginal and circulatory-death donors, interest returned to machine perfusion, and randomized trials in kidney and liver transplantation moved perfusion from concept toward clinical adoption (Moers et al., 2009; Nasralla et al., 2018).
Key figures
- Folkert Belzer
- James Southard
- Holger Eltzschig
Related topics
Seminal works
- southard-belzer-1989
- eltzschig-eckle-2011
- moers-2009
- nasralla-2018
Frequently asked questions
- What is the difference between organ preservation and reperfusion injury?
- Preservation is what keeps the organ viable while it has no normal circulation; reperfusion injury is the damage that can occur when circulation is restored. They are linked because the duration and conditions of preservation influence how severe the reperfusion injury becomes.
- Why is machine perfusion of interest if cold storage already works?
- Cold static storage is simple and effective for many organs, but machine perfusion can maintain flow and, in normothermic form, allow the organ to function and be assessed during storage. Randomized trials have examined whether this improves outcomes relative to cold storage, especially for marginal grafts.