Metabolic profile of pancreatic acinar and islet tissue in culture

Background. The amount and condition of exocrine impurities may affect the quality of islet preparations, especially during culture. In this study, the objective was to determine the oxygen demand and viability of islet and acinar tissue post-isolation and whether they change disproportionately while in culture. Method. We compared the oxygen consumption rate (OCR) normalized to DNA (OCR/DNA, a measure of fractional viability in units of nmol/min/mg DNA), and the percent change in OCR and DNA recoveries between adult porcine islet and acinar tissue from the same preparation (paired) over 6-9 days of standard culture. Paired comparisons were done to quantify differences in OCR/DNA between islet and acinar tissue from the same preparation, at specified time points during culture. Results. The mean (±SE) OCR/DNA was 74.0 ± 11.7 units higher for acinar (vs islet) tissue on the day of isolation (n = 16, P <.0001), but 25.7 ± 9.4 units lower after 1 day (n = 8, P =.03), 56.6 ± 11.5 units lower after 2 days (n = 12, P =.0004), and 65.9 ± 28.7 units lower after 8 days (n = 4, P =.2) in culture. DNA and OCR recoveries decreased at different rates for acinar versus islet tissue over 6-9 days in culture (n = 6). DNA recovery decreased to 24 ± 7% for acinar and 75 ± 8% for islets (P =.002). Similarly, OCR recovery decreased to 16 ± 3% for acinar and remained virtually constant for islets (P =.005). Conclusion. Differences in the metabolic profile of acinar and islet tissue should be considered when culturing impure islet preparations. OCR-based measurements may help optimize pre-islet transplantation culture protocols.