386838 Pancreas Digestion Using an Automated Tissue Digester
Pancreatic digestion is the primary step in preparing islets of Langerhans for clinical transplantation for restoring euglycemia in Type-1 diabetes patients. The yield of islets from the traditional method developed by Ricordi et al. tends to be variable and depends on several parameters. Operator function (shaking the vessel by hand) also produces variability from case to case and can cause damage to the recovered islets. An automated horizontally rotating digester (MDR) capable of producing reproducible operating parameters is needed for the consistent preparation of islets. The characteristics of the newly designed digester can be applied to an automatic mode (controlled rotation speed) instead of manual (shaking) operation.
A pig pancreas infused intraductally with collagenase enzyme blend was digested by using both the MDR and the Ricordi chamber in order to compare the islet yield and other relevant parameters. The MDR was operated at optimized differential rotation rate of 50 rpm, allowing complete tissue suspension in a favorable digestion environment. Enhanced turbulent effects and maximized contact area increased the probability of collision and mixing between tissue fragments and vanes. The experimental data, including mean islet diameter and islet equivalent quantification (IEQ), are categorized and presented as two-series histograms for comparison. The MDR digestion proceeded more rapidly, uniformly and extensively than that in the Ricordi chamber, with clear evidence that excessive digestion occurred in the MDR. Exocrine tissue is digested to smaller fragments and no islets remained attached to exocrine tissue in the MDR while 32.61 per cent of the islets are still embedded in or mantled by larger tissue pieces in the Ricordi chamber digests. The MDR yielded extensive digestion of the pancreas leaving 29% less undigested tissue and cleaner islets.