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Download fileAlginate Microencapsulation of Human Islets Does Not Increase Susceptibility to Acute Hypoxia
journal contribution
posted on 2016-04-04, 00:00 authored by I. K. Hals, A. M. Rokstad, B. L. Strand, J. Oberholzer, V. GrillIslet transplantation in diabetes is hampered by the need of life-long immunosuppression. Encapsulation provides partial
immunoprotection but could possibly limit oxygen supply, a factor that may enhance hypoxia-induced beta cell death in the early
posttransplantation period. Here we tested susceptibility of alginate microencapsulated human islets to experimental hypoxia (0.1–
0.3% O2 for 8 h, followed by reoxygenation) on viability and functional parameters. Hypoxia reduced viability as measured by
MTT by 33.8 ± 3.5% in encapsulated and 42.9 ± 5.2% in nonencapsulated islets (𝑃 < 0.2). Nonencapsulated islets released 37.7%
(median) more HMGB1 compared to encapsulated islets after hypoxic culture conditions (𝑃 < 0.001). Glucose-induced insulin
release was marginally affected by hypoxia. Basal oxygen consumption was equally reduced in encapsulated and nonencapsulated
islets, by 22.0 ± 6.1% versus 24.8 ± 5.7%. Among 27 tested cytokines/chemokines, hypoxia increased the secretion of IL-6 and
IL-8/CXCL8 in both groups of islets, whereas an increase of MCP-1/CCL2 was seen only with nonencapsulated islets. Conclusion.
Alginate microencapsulation of human islets does not increase susceptibility to acute hypoxia.This is a positive finding in relation
to potential use of encapsulation for islet transplantation.