Cytokine-induced functional suppression of microencapsulated rat pancreatic islets in vitro.
BACKGROUND
It is likely that inflammatory cytokines are released near microencapsulated islets in vivo.


METHODS
Rates of insulin release or glucose oxidation were measured after culture of microencapsulated rat islets with interleukin (IL)-1beta and tumor necrosis factor-(TNF-alpha). Their ability to recover from IL-1beta-induced suppression was also investigated.


RESULTS
Microencapsulated islets were suppressed after exposure to IL-1beta, which was potentiated by TNF-alpha. After exposure to lower IL-1beta concentrations, microencapsulated islets had similar oxidation rates as corresponding controls. At higher concentrations, microencapsulated islets were more suppressed than nonencapsulated islets. Microencapsulated and control islets were able to recover from suppression after exposure to 2.5 U/ml of IL-1beta.


CONCLUSIONS
Microencapsulation using the present alginate/poly-L-lysine/alginate capsules does not protect islets against the detrimental effects of IL-1beta and TNF-alpha. Indeed, microencapsulated islets seem to be more susceptible to suppression at higher concentrations of IL-1beta. However, after exposure to a lower concentration of IL-1beta, microencapsulated islets can recover.
Department of Medical Cell Biology, Biomedicum, Uppsala University, Sweden. aileen.king@medcellbiol.uu.SE
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King
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Andersson
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Sandler
D000818:Animals; D002478:Cells, Cultured; D003470:Culture Media / Q000737:chemistry; D016207:Cytokines / Q000494:pharmacology*; D004339:Drug Compounding; D005947:Glucose / Q000378:metabolism; D007108:Immune Tolerance / Q000187:drug effects; D007328:Insulin / Q000378:metabolism; D000078790:Insulin Secretion; D007375:Interleukin-1 / Q000494:pharmacology; D007515:Islets of Langerhans / Q000502:physiology*; D008297:Male; D009573:Nitrites / Q000378:metabolism; D010084:Oxidation-Reduction; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
D003470:Culture Media; D016207:Cytokines; D007328:Insulin; D007375:Interleukin-1; D009573:Nitrites; D014409:Tumor Necrosis Factor-alpha; D005947:Glucose