Acute alcohol consumption attenuates interleukin-8 (IL-8) and monocyte chemoattractant peptide-1 (MCP-1) induction in response to ex vivo stimulation

Chemokines MCP-1 and RANTES in isolated rat pancreatic acinar cells treated with CCK and ethanol in vitro

The role of cholecystokinin (CCK) and ethanol on the expression and secretion of monocyte chemoattractant protein-1 (MCP-1) and regulated on activation, normal T-cell expressed and secreted (RANTES) chemokines from isolated rat pancreatic acinar cells was investigated. CCK at concentrations of 1 nM and 100 nM and ethanol at concentrations of 75, 200, 400, and 600 mM were used to stimulate isolated acini. The levels of MCP-1 and RANTES in the incubation medium were determined by enzyme-linked immunoabsorbent assay (ELISA). In the control groups, MCP-1 and RANTES were secreted into the incubation medium, and both increased with time. MCP-1 increased from baseline 17.6 pg/ml to 74.1 pg/ml, whereas RANTES increased from 255.5 to 318.3 pg/ml at 390 min. CCK at 100 nM caused a sustained increase in MCP-1 levels to 89.6 pg/ml at 390 min in the incubation medium, whereas the levels of RANTES gradually decreased after 180 min and reached its lowest level at 390 min. Ethanol at a concentration of 600 mM increased the levels of RANTES in the incubation medium, but inhibited the levels of MCP-1 at all concentrations (75, 200, 400, and 600 mM). In summary, rat pancreatic acinar cells secrete MCP-1 and RANTES, and the stimulation of these chemokines by CCK and ethanol suggests that they may be involved in the pathogenesis of acute pancreatitis.

Increased monocyte nuclear factor-kappaB activation and tumor necrosis factor production in alcoholic hepatitis

Increased tumor necrosis factor-a activity has been reported in patients with alcoholic hepatitis and is implicated in its pathogenesis. The aim of this study was to investigate potential mechanisms of increased tumor necrosis factor-a activity in alcoholic hepatitis. Monocyte nuclear factor-kB activity was assessed by electrophoretic mobility shift assay, monocyte tumor necrosis factor-a mRNA was semi-quantitatively assessed by reverse transcriptase polymerase chain reaction, and tumor necrosis factor-a in monocyte culture supernatants was measured. There was significantly greater spontaneous nuclear factor-kB activity in the monocytes of 6 patients with alcoholic hepatitis as compared with that in the monocytes of control subjects. There was spontaneous tumor necrosis factor-a mRNA and tumor necrosis factor-a release from the monocytes of patients with alcoholic hepatitis but not from the monocytes of normal subjects. Endotoxin increased nuclear factor-kB activity and induced tumor necrosis factor-a mRNA and tumor necrosis factor-a release from normal subjects' monocytes. Endotoxin further increased nuclear factor-kB activity, tumor necrosis factor-a mRNA, and tumor necrosis factor-a release from the monocytes of patients with alcoholic hepatitis. Supershift assays indicate that the monocyte nuclear factor-kB activation involves the p50 and p65 subunits. Dysregulated tumor necrosis factor-a metabolism in alcoholic hepatitis monocytes is associated with increased nuclear factor-kB activity and tumor necrosis factor-a mRNA expression.

Inhibition of lipopolysaccharide-mediated NFkappaB activation by ethanol in human monocytes

Alcohol use is typically associated with impaired immunity and increased host susceptibility to infection, partially due to decreased inflammatory response. Acute ethanol exposure has been shown to down-regulate monocyte production of inflammatory cytokines. Activation of the pluripotent transcription factor NFkappaB is a pivotal step in the induction of inflammatory cytokines, chemokines and growth factors. Therefore, we hypothesized that alcohol may alter NFkappaB activation, thus providing a mechanism for the decreased inflammatory cytokine production by monocytes after acute alcohol treatment. We show here for the first time that alcohol inhibits lipopolysaccharide (LPS)-induced NFkappaB activation in human monocytes by decreasing DNA binding of the p65/p50 heterodimer as seen in electrophoretic mobility shift and supershift assays. We also demonstrate that alcohol prevents LPS-induced nuclear translocation of p65 and to a lesser extent that of the p50 subunits. NFkappaB activation is regulated via phosphorylation and proteolytic degradation of IkappaB. Thus, we investigated the effect of acute ethanol treatment on IkappaB in human monocytes. Alcohol did not prevent LPS-induced IkappaBalpha degradation but decreased the levels of phospho-specific IkappaBalpha (Ser32). Finally, for the first time we show that de novo protein synthesis is necessary to bring about the ethanol-mediated inhibition of LPS-induced NFkappaB activation. Consequently, these results suggest that physiologically relevant concentrations of alcohol interfere with NFkappaB activation and thereby may affect the regulation of NFkappaB-controlled gene activation.