Modified method of human islet isolation and purification for clinical transplantation

ObjectiveTo investigate the methods of islet isolation and purification so as to get more islet cells with high purity and good function for clinical transplantation.MethodsHuman pancreas was digested with Liberase HI.The islets were isolated by the improved Recordi's automated islet isolation system,followed by purification in a Ficoll continuous gradient centrifugation using Cobe 2991 cell separator.After purification,the islet cell yield and purity were evaluated by DTZ staining under microscope and the activity was evaluated by AO-PI staining under fluorescence microscope.The islet's function was assessed by insulin release assay in vitro.ResultsThe islets were isolated from thirty pancreases.After purification,an average of(316 626±191 972) islet equivalents(IEQ) was obtained from each pancreas,with an average purity of(74.70±7.84)% and activity of(94.10±2.19)%.The islets responded well to glucose stimulation with a 3.68-fold increase of insulin secretion over the basal level.Seven patients with type 1 diabetes accepted islet transplantation with expected outcomes.ConclusionThe improved Recordi's automated islet isolation system can provide high-purity islet cells for clinical transplantation.