Evaluation of the viability and energy metabolism of canine pancreas graft subjected to significant warm ischemia damage during preservation by UW solution cold storage method

Pancreas Transplantation from Donors after Circulatory Death: an Irrational Reluctance?

PURPOSE OF REVIEW

Beta-cell replacement is the best therapeutic option for patients with type 1 diabetes. Because of donor scarcity, more extended criteria donors are used for transplantation. Donation after circulatory death donors (DCD) are not commonly used for pancreas transplantation, because of the supposed higher risk of complications. This review gives an overview on the pathophysiology, risk factors, and outcome in DCD transplantation and discusses different preservation methods.

RECENT FINDINGS

Studies on outcomes of DCD pancreata show similar results compared with those of donation after brain death (DBD), when accumulation of other risk factors is avoided. Hypothermic machine perfusion is shown to be a safe method to improve graft viability in experimental settings. DCD should not be the sole reason to decline a pancreas for transplantation. Adequate donor selection and improved preservation techniques can lead to enhanced pancreas utilization and outcome.

Current state of pancreas preservation and implications for DCD pancreas transplantation

One of the main factors limiting potential uptake of pancreas transplantation, particularly in the United Kingdom, is the shortage of grafts. There has therefore been a recent expansion, particularly in the United Kingdom, in the utilization of grafts from donation after cardiac death (DCD) donors. These grafts are subjected to a greater ischemic insult and are arguably at higher risk of poor functional outcome. Although conventional preservation techniques may be adequate for donation after brain death (DBD) and low-risk DCD pancreases, as the number of DCD pancreas transplants increase and the threshold for rejecting organs decreases, the importance of optimal preservation techniques is going to increase. Over recent years, there have been significant advances in preservation techniques for DCD kidneys, improving the outcome of these marginal grafts. However, the use of such techniques for pancreas preservation is extremely limited and mainly historical. This overview describes the background and results of the established method of pancreas preservation for DBD, namely, cold static storage, and describes the use of the two-layer method. It also reviews pulsatile machine perfusion and normothermic perfusion for pancreas preservation techniques, which have shown promise in the preservation of DCD kidney grafts. The use of these techniques in pancreas preservation is predominantly historical but warrants reevaluation as to the feasibility of applying these techniques to DCD pancreas grafts not only for preservation but also for viability assessment. Further areas for development of pancreas preservation are discussed.

Expanding the donor pool in pancreas transplantation

PURPOSE OF REVIEW

The current era of organ shortage has necessitated expansion of the currently available organ donor pool, to increase the number of pancreases available for transplant. This review summarizes the cumulative efforts of various centers in making this possible.

RECENT FINDINGS

Various centers are consistently reporting their experience with marginal donors; recent additions to the cohort have been increase in pancreases from donors after cardiac death (controlled and uncontrolled), update on long-term outcomes of live pancreas donors, as well as efforts at objectively assessing donor risk.

SUMMARY

It has become important for the transplanting surgeon to make difficult decisions on organ suitability and appropriateness depending upon the recipient's status. Further more, limiting further damage to these vulnerable grafts is important in improving utilization as well as successful transplantation.

Pancreatic ischemia/reperfusion injury: impact of different preservation temperatures

OBJECTIVES

Pancreatic ischemia/reperfusion injury (IRI) can influence the results after transplantation. Temperature during ischemia can affect IRI. A temperature of 4 degrees C is assumed as optimal for graft preservation. There are no data about the impact of different ischemia temperatures in pancreatic IRI.

METHODS

Ischemia/reperfusion injury was induced in pancreatic tail segments (2-hour ischemia, 2-hour reperfusion), with rats (7/group) without ischemia served as control. Animals were randomized to the different experimental groups. To achieve the desired temperature (4, 18, or 37 degrees C and 37 degrees C control), pancreatic tail segments were superfused with temperated saline. After reperfusion, microcirculation was observed by intravital fluorescence microscopy. Functional capillary density (FCD), leukocyte adherence in post-capillary venules, and histological damage were analyzed.

RESULTS

In IRI groups, decrease of FCD 1 and 2 hours after reperfusion compared with baseline measurements was significant. Functional capillary density in 4 degrees C was better as compared with 18 and 37 degrees C after reperfusion. Lower adherent leukocytes were seen in 4 and 18 degrees C, compared with 37 degrees C and also to CO. In 4 degrees C, histological damage was lower as compared with 18 and 37 degrees C.

CONCLUSIONS

We could demonstrate that also in pancreatic IRI, tissue injury is temperature dependent. Compared with 37 degrees C, although a protective effect is established already at 18 degrees C, more protection is achieved with storage at 4 degrees C. Our data suggest that 4 degrees C has the best protective effect on pancreatic IRI.