Prolonged anoxia has deleterious effects on islets. Gas-permeable cell culture devices can be used to minimize anoxia during islet culture and especially during shipment when elimination of gas-liquid interfaces is required to prevent the formation of damaging gas bubbles. Gas-permeable bags may have several drawbacks, such as propensity for puncture and contamination, difficult islet retrieval, and significantly lower oxygen permeability than silicone rubber membranes (SRM). We hypothesized that oxygen permeability of bags may be insufficient for islet oxygenation. We measured oxygen transmission rates through the membrane walls of three different types of commercially available bags and through SRM currently used for islet shipment. We found that the bag membranes have oxygen transmission rates per unit area about 100-fold lower than SRM. We solved the oxygen diffusion-reaction equation for 150-μm diameter islets seeded at 3000 islet equivalents per cm2, a density adequate to culture and ship an entire human or porcine islet preparation in a single gas-permeable device, predicting that about 40% of the islet volume would be anoxic at 22°C and about 70% would be anoxic at 37°C. Islets of larger size or islets accumulated during shipment would be even more anoxic. The model predicted no anoxia in islets similarly seeded in devices with SRM bottoms. We concluded that commercially available bags may not prevent anoxia during islet culture or shipment; devices with SRM bottoms are more suitable alternatives.
|Original language||English (US)|
|Number of pages||6|
|State||Published - Mar 2008|
Bibliographical noteFunding Information:
We are thankful for the financial support from NIH (NCRR and NIDDK), JDRF, the Iacocca Foundation, the Schott Foundation, and the Carol Olson Memorial Diabetes Research Fund. We also thank Matthew Hanson (University of Wisconsin) for helpful discussions and for providing extra OriGen bags for assessment of thickness variability; American Fluoroseal and OriGen for providing free samples of their commercially available bags; Michael Kragness of MOCON Testing Service for OTR and thickness measurements; and Denice Dudero, Laurie Macleod, Dr. Kristen Maynard, Heather Nelson, Christine Vincent and Gina Wildey (UMN, DIIT) for administrative help.