Abstract

Successful pancreatic islet transplantation depends on the number of islets
transplanted, islet viability and extent of early islet loss due to ischaemia reperfusion
injury. Novel pancreas preservation techniques which can improve these variables can
increase the utilisation of non-heart-beating-donor pancreases for islet transplantation.
A non-heart-beating-donor rat pancreas preservation model was developed.
Pancreases preserved by either static cold storage, hypothermic machine perfusion or
portal venous oxygen persufflation underwent islet isolation and purification. The yield,
viability and in vitro function of isolated islets were compared. Portal venous oxygen
persufflation improved the islet yield, viability and morphology as compared to static
cold storage. The percentage of pancreases with functional islets (stimulation index
greater than 1.0) was also higher after oxygen persufflation as compared to static cold
storage.
Severity of reperfusion injury in pancreases preserved by static cold storage or portal
venous oxygen persufflation was compared after in vitro warm reperfusion. Amylase,
lipase and glycerol levels in the portal effluent were measured. Lipid peroxidation and
apoptosis in reperfused pancreas were measured using thio-barbituric acid reactive
substances assay and caspase 3 assay respectively. Expression of genes relevant to
ischaemia reperfusion was compared using RNA microarrays.
Severity of ischaemia reperfusion injury was similar in both groups. Microarray analysis
revealed increased expression of genes related to apoptosis in the portal venous
oxygen persufflation group. This group also showed up-regulation of pro-survival cellular pathways and over-expression of genes related to cellular repair as compared
to static cold storage.
This project has for the first time evaluated oxygen persufflation as a method of
pancreas preservation and investigated changes in global gene expression after this
form of preservation. Overall, the project suggests that portal venous oxygen
persufflation improves the recovery of non-heart-beating-donor rat pancreas. Further
investigation to examine its role in the preservation of large animal pancreases is
needed.