Diabetes, Vol 36, Issue 5 641-647, Copyright © 1987 by American Diabetes Association
Islet cytotoxicity of interleukin 1. Influence of culture conditions and islet donor characteristics
T Mandrup-Poulsen, GA Spinas, SJ Prowse, BS Hansen, DW Jorgensen, K Bendtzen, JH Nielsen and J Nerup
We recently demonstrated that the macrophage product interleukin 1 (IL-1)
is cytotoxic to isolated pancreatic islets and hypothesized that IL-1 is
responsible for beta-cell destruction in insulin-dependent diabetes
mellitus (IDDM). We studied whether the variation in IDDM preponderance
with age, sex, and genetic background in vivo is reflected in different
susceptibility to IL-1 toxicity of islets in vitro. In addition, we studied
the effect of preculture conditions that support endocrine islet cell
function and decrease nonendocrine passenger-cell survival on the
susceptibility of beta-cells to IL-1 because it is unknown whether IL-1
acts directly on beta-cells or via passenger cells. No differences in
susceptibility to various doses of IL-1-containing mononuclear cell
supernatants were found between islets isolated from newborn or adult rats,
male or female rats, or rats of four inbred strains, indicating that age,
sex, and genetic background do not influence the susceptibility of the
beta-cell to IL-1. Preculture of islets for 1-7 days in normal atmosphere
and preculture of islet clusters in 95% O2 to delete passenger cells did
not affect IL-1-mediated cytotoxicity, suggesting that IL-1 acts directly
on beta-cells. Increasing the glucose concentration (22 mM) in the culture
medium, which is known to protect beta-cells against alloxan toxicity,
reduced IL-1 toxicity. Five or 25% normal human serum as well as 5% normal
rat serum, but not equivalent concentrations of human serum albumin,
inhibited IL-1 toxicity, indicating the presence of IL-1 inhibitors, IL-1
antagonists, or beta-cell-protecting factors in normal serum.(ABSTRACT
TRUNCATED AT 250 WORDS)