Impact of Islet Purification in Canine Pancreas Islet Cell Transplantation

ABSTRACT

Purification of islets in pancreas islet cell transplantation has some potential advantages ,such as more safety, improved islet cell implantation, and reduced immunogenicity, compared with an unpurified pancreas islet cell transplantation. We evaluated the effect of islet cell purification on islet yields, hemodynamics, and graft outcome following intraportal canine pancreas islet cell transplantation. The baseline characteristics, including body weight, pancreas weight and collagenase recirculation time for the unpurified group(n=12) and the purified group(n=17) did not show any significant difference(P>0.05). The mean cell pellet volume before intraportal injection was 25.4 ml in the unpurified group and 7.2ml in the purified group(P0.05). Mean recovery rate of islet after purification was 66.8%. The portal pressure change after intraportal islet injection was significantly less in the purified group(16.2+/-11.3 cmH2O vs 6.2+/-2.0 cmH2O, P OR =70%, n=4 vs low purity <70%, n=13) in the purified group, showed significant hemodynamic stability in the high purity group, but no significant difference in the islet recovery rate between the low and high purity group(58.6% vs 61.7%). Glucose was controlled in 3 cases(25.0%) in the unpurified group and 7 cases(41.2%) in the purified group. Death due to portal hypertension occurred in 2 cases(16.7%) in unpurified group and 2 cases(11.7%) in the purified group. Interestingly, in the highly purified group, all the animals were alive with normoglycemia during the follow up period. We conclude that purified pancreas islet cell transplantation, especially in a highly purified group, has distinct hemodynamic advantages compared with unpurified islet transplantation following intraportal islet injection. However further research to develop the methods that will minimize the loss of islet yields during purification and enhance the purity is neccessary to achieve a successful islet transplantation with a long-term good result.