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Long-term viability and function of transplanted islets macroencapsulated at high density are achieved by enhanced oxygen supply


Evron, Yoav; Colton, Clark K; Ludwig, Barbara; Weir, Gordon C; Zimermann, Baruch; Maimon, Shiri; Neufeld, Tova; Shalev, Nurit; Goldman, Tali; Leon, Assaf; Yavriyants, Karina; Shabtay, Noa; Rozenshtein, Tania; Azarov, Dimitri; DiIenno, Amanda R; Steffen, Anja; de Vos, Paul; Bornstein, Stefan R; Barkai, Uriel; Rotem, Avi (2018). Long-term viability and function of transplanted islets macroencapsulated at high density are achieved by enhanced oxygen supply. Scientific Reports, 8(1):6508.

Abstract

Transplantation of encapsulated islets can cure diabetes without immunosuppression, but oxygen supply limitations can cause failure. We investigated a retrievable macroencapsulation device wherein islets are encapsulated in a planar alginate slab and supplied with exogenous oxygen from a replenishable gas chamber. Translation to clinically-useful devices entails reduction of device size by increasing islet surface density, which requires increased gas chamber pO Here we show that islet surface density can be substantially increased safely by increasing gas chamber pO to a supraphysiological level that maintains all islets viable and functional. These levels were determined from measurements of pO profiles in islet-alginate slabs. Encapsulated islets implanted with surface density as high as 4,800 islet equivalents/cm in diabetic rats maintained normoglycemia for more than 7 months and provided near-normal intravenous glucose tolerance tests. Nearly 90% of the original viable tissue was recovered after device explantation. Damaged islets failed after progressively shorter times. The required values of gas chamber pO were predictable from a mathematical model of oxygen consumption and diffusion in the device. These results demonstrate feasibility of developing retrievable macroencapsulated devices small enough for clinical use and provide a firm basis for design of devices for testing in large animals and humans.

Abstract

Transplantation of encapsulated islets can cure diabetes without immunosuppression, but oxygen supply limitations can cause failure. We investigated a retrievable macroencapsulation device wherein islets are encapsulated in a planar alginate slab and supplied with exogenous oxygen from a replenishable gas chamber. Translation to clinically-useful devices entails reduction of device size by increasing islet surface density, which requires increased gas chamber pO Here we show that islet surface density can be substantially increased safely by increasing gas chamber pO to a supraphysiological level that maintains all islets viable and functional. These levels were determined from measurements of pO profiles in islet-alginate slabs. Encapsulated islets implanted with surface density as high as 4,800 islet equivalents/cm in diabetic rats maintained normoglycemia for more than 7 months and provided near-normal intravenous glucose tolerance tests. Nearly 90% of the original viable tissue was recovered after device explantation. Damaged islets failed after progressively shorter times. The required values of gas chamber pO were predictable from a mathematical model of oxygen consumption and diffusion in the device. These results demonstrate feasibility of developing retrievable macroencapsulated devices small enough for clinical use and provide a firm basis for design of devices for testing in large animals and humans.

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Item Type:Journal Article, refereed, original work
Communities & Collections:04 Faculty of Medicine > University Hospital Zurich > Clinic for Endocrinology and Diabetology
Dewey Decimal Classification:610 Medicine & health
Scopus Subject Areas:Health Sciences > Multidisciplinary
Language:English
Date:25 April 2018
Deposited On:04 Jul 2018 12:56
Last Modified:08 Apr 2020 23:45
Publisher:Nature Publishing Group
ISSN:2045-2322
OA Status:Gold
Free access at:PubMed ID. An embargo period may apply.
Publisher DOI:https://doi.org/10.1038/s41598-018-23862-w
PubMed ID:29695723

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