Chronic alcohol exposure exacerbates inflammation and triggers pancreatic acinar-to-ductal metaplasia through PI3K/Akt/IKK.

Abstract

Pancreatic acinar-to-ductal metaplasia (ADM) has been identified as an initiating event that can progress to pancreatic intraepithelial neoplasia (PanIN) or pancreatic ductal adenocarcinoma (PDAC). Acini transdifferentiation can be induced by persistent inflammation. Notably, compelling evidence has emerged that chronic alcohol exposure may trigger an inflammatory response of macrophages/monocytes stimulated by endotoxins. In the present study, we aimed to evaluate the role of inflammation induced by chronic alcohol and lipopolysaccharide (LPS) exposure in the progression of pancreatic ADM, as well as to elucidate the possible mechanisms involved. For this purpose, cultured macrophages were exposed to varying doses of alcohol for 1 week prior to stimulation with LPS. Tumor necrosis factor-α (TNF-α) and regulated upon activation, normal T cell expression and secreted (RANTES) expression were upregulated in the intoxicated macrophages with activated nuclear factor-κB (NF-κB). Following treatment with the supernatant of intoxicated macrophages, ADM of primary acinar cells was induced. Furthermore, the expression of TNF-α and RANTES, as well as the phosphatidylinositol-3-kinase (PI3K)/protein kinase B(Akt)/inhibitory κB kinase (IKK) signaling pathway have been proven to be involved in the ADM of acinar cells. Moreover, Sprague-Dawley (SD) rats were employed to further explore the induction of pancreatic ADM by chronic alcohol and LPS exposure in vivo. At the end of the treatment period, a number of physiological parameters, such as body weight, liver weight and pancreatic weight were reduced in the exposed rats. Plasma alcohol concentrations and oxidative stress levels in the serum, as well as TNF-α and RANTES expression in monocytes were also induced following chronic alcohol and LPS exposure. In addition, pancreatic ADM was induced through the PI3K/Akt/IKK signaling pathway by the augmented TNF-α and RANTES expression levels in the exposed rats. Overall, we characterized the link between inflammation induced by chronic alcohol and LPS exposure and pancreatic ADM. However, the mechanisms behind the induction of pancreatic ADM warrant further investigation.