Role of pro-inflammatory cytokines of pancreatic islets and prospects of elaboration of new methods for the diabetes treatment

Abstract

Several relations between cytokines and pathogenesis of diabetes are reviewed. In type 1 and type 2 diabetes an increased synthesis is observed and as well as the release of pro-inflammatory cytokines, which cause the damage of pancreatic islet cells and, in type 2 diabetes, the development of the insulin resistance. That process results in the disturbed balance between pro-inflammatory and protective cytokines. Pro-inflammatory cytokines such as interleukin 1β (IL-1β), tumor necrosis factor-α (TNF-α) and interferon-γ (IFN-γ), as well as recently discovered pancreatic derived factor PANDER are involved in the apoptosis of pancreatic β-cells. Inside β-cells, cytokines activate different metabolic pathways leading to the cell death. IL-1β activates the mitogen-activated protein kinases (MAPK), affects the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) and activates the inducible nitric oxide synthase (iNOS). TNF-α and IFN-γ in a synergic way activate calcium channels, what leads to the mitochondrial dysfunction and activation of caspases. Neutralization of pro-inflammatory cytokines, especially interleukin 1β with the IL-1 receptor antagonist (IL-1Ra) and/or IL-1β antibodies might cause the extinction of the inflammatory process of pancreatic islets, and consequently normalize concentration of glucose in blood and decrease the insulin resistance. In type 1 diabetes interleukin-6 participates in regulation of balance between Th17 and regulatory T cells. In type 2 diabetes and obesity, the long-duration increase of IL-6 concentration in blood above 5 pg/ml leads to the chronic and permanent increase in expression of SOCS3, contributing to the increase in the insulin resistance in cells of the skeletal muscles, liver and adipose tissue.