The effect of alginate and hyaluronate on the viability and function of immunoisolated neonatal rat islets

Recent observations suggest that the extracellular matrix plays a role as r egards the viability and morphological integrity in long-term culture of La ngerhans islets. For the present study we encapsulated neonatal rat islets without extracellular matrix (WEM), with alginate solution (AL) and with hy aluronate solution (HY) into cuprophane hollow fibers. Function was tested after week 1 and 5. The insulin release of WEM encapsulated islets decrease d significantly during the culture period. In contrast to this, AL and HY e mbedded islets had stable secretion values throughout the whole cultivation . Histological examination confirmed that viability of HY and of AL embedde d islets differed significantly from that of WEM encapsulated islets. Furth ermore, HY seems to be a more advantageous environment to immunoisolated is lets than AL. Both the insulin secretion values and the viability of HY emb edded islets were higher than of AL embedded islets. We conclude that an ex tracellular matrix is important for immunoisolated islets, to maintain thei r function and morphological integrity and that HY is especially suitable f or this application. (C) 1999 Elsevier Science Ltd. All rights reserved.