Endotoxin-mediated activation of cytokine production in human PBMCs by collagenase and Ficoll.

Endotoxin-induced early inflammatory reactions may inhibit the function and survival of isolated cells or cell aggregates after transplantation. By the chromogenic Limulus amebocyte lysate assay we found rather high but variable endotoxin concentrations in the chemicals used for islet isolation, i.e. collagenase and Ficoll. Liberase, a special collagenase preparation from Boehringer, was nearly endotoxin-free. Correlating to the endotoxin content, collagenase and Ficoll had the capacity to induce interleukin-1beta release from human peripheral blood mononuclear cells. Because collagenase and density gradient media are needed in most cell isolation procedures from solid organs, each lot of these chemicals should be tested for endotoxin contamination. In pancreatic islet transplantation, the use of endotoxin-free chemicals may diminish early local inflammatory reactions at the graft site and thereby reduce the number of islets needed for successful islet transplantation.