Short-term preexposure of mononuclear cells to epinephrine inhibits LPS-induced production of TNF, whereas preexposure for 24 h results in increased TNF production. To assess the effects of epinephrine infusions of varying duration on in vivo responses to LPS, the following experiments were performed: ( a ) Blood obtained from eight subjects at 4-24 h after the start of a 24-h infusion of epinephrine (30 ng/kg per min) produced less TNF after ex vivo stimulation with LPS compared with blood drawn before the start of the infusion, and ( b ) 17 healthy men who were receiving a continuous infusion of epinephrine (30 ng/kg per min) started either 3 h (EPI-3; n ϭ 5) or 24 h (EPI-24; n ϭ 6) before LPS injection or an infusion of normal saline (LPS; n ϭ 6) were studied after intravenous injection of LPS (2 ng/kg, lot EC-5). EPI-3 inhibited LPS-induced in vivo TNF appearance and also increased IL-10 release (both P Ͻ 0.005 versus LPS), whereas EPI-24 only attenuated TNF secretion ( P ϭ 0.05). In separate in vitro experiments in whole blood, epinephrine increased LPS-induced IL-10 release by a combined effect on ␣ and ␤ adrenergic receptors. Further, in LPS-stimulated blood, the increase in IL-10 levels caused by epinephrine only marginally contributed to concurrent inhibition of TNF production. Epinephrine, either endogenously produced or administered as a component of sepsis treatment, may have a net antiinflammatory effect on the cytokine network early in the course of systemic infection. ( J. Clin. Invest. 1996. 97:713-719.)

The aim of the present study was to analyze the action of metformin on short-term memory, glial cell activation and neuroinflammation caused by experimental diabetic encephalopathy in C57BL/6 mice. Diabetes was induced by the intraperitoneal injection of a dose of 90mg/kg of streptozotocin on two successive days. Mice with blood glucose levels ≥200dl/ml were considered diabetic and were given metformin hydrochloride at doses of 100mg/kg and 200mg/kg (by gavage, twice daily) for 21 days. On the final day of treatment, the mice underwent a T-maze test. On the 22nd day of treatment all the animals were anesthetized and euthanized. Diabetic animals treated with metformin had a higher spatial memory score. The hippocampus of the diabetic animals presented reactive gliosis, neuronal loss, NF-kB signaling activation, and high levels of IL-1 and VEGF. In addition, the T-maze test scores of these animals were low. Treatment with metformin reduced the expression of GFAP, Iba-1 (astrocyte and microglial markers) and the inflammation markers (p-IKB, IL-1 and VEGF), while enhancing p-AMPK and eNOS levels and increasing neuronal survival (Fox-1 and NeuN). Treatment with metformin also improved the spatial memory scores of diabetic animals. In conclusion, the present study showed that metformin can significantly reduce neuroinflammation and can decrease the loss of neurons in the hippocampus of diabetic animals, which can subsequently promote improvements in spatial memory.

Leukocytes rapidly lose their surface receptors for tumor necrosis factor (TNF) after exposure to various stimuli in vitro. To assess the effect of endotoxin on cellular TNF receptors in humans in vivo, binding of biotinylated TNF to circulating monocytes and granulocytes was determined by fluorescence-activated cell sorter analysis in six healthy subjects after intravenous injection of endotoxin (lot EC-5, 20 U/kg). Endotoxin administration was associated with a transient decrease in monocyte TNF receptors, reaching a nadir after 2 hours (P < .0001), and a more sustained decrease in granulocyte TNF receptors (P < .001). Although the decrease in cellular TNF receptors coincided with increases in soluble TNF receptors types I and II, no correlations were observed between trough monocyte or granulocyte TNF receptors and peak plasma concentrations of soluble TNF receptors. Stimulation of human whole blood with endotoxin resulted in reduced expression of both type I and type II TNF receptors on monocytes and granulocytes. Endotoxin induces downmodulation of monocyte and granulocyte TNF surface receptors in humans in vivo, which may represent a mechanism to reduce excessive activity of TNF during systemic infection.

This study investigated the anti-inflammatory effects of DEC on the CCl4-induced hepatotoxicity in C57BL/6 mice. Chronic inflammation was induced by i.p. administration of CCl4 0.5 μL/g of body weight through two injections a week for 6 weeks. DEC (50 mg/kg) was administered by gavage for 12 days before finishing the CCl4 induction. Histological analyses of the DEC-treated group exhibited reduced inflammatory process and prevented liver necrosis and fibrosis. Immunohistochemical and immunofluorescence analyses of the DEC-treated group showed reduced COX-2, IL1β, MDA, TGF-β, and αSMA immunopositivity, besides exhibiting decreased IL1β, COX-2, NFκB, IFNγ, and TGFβ expressions in the western blot analysis. The DEC group enhanced significantly the IL-10 expression. The reduction of hepatic injury in the DEC-treated group was confirmed by the COX-2 and iNOS mRNA expression levels. Based on the results of the present study, DEC can be used as a potential anti-inflammatory drug for chronic hepatic inflammation.

Some pharmacological studies showed that diethylcarbamazine (DEC) interferes with the arachidonic acid metabolism, acting as an anti-inflammatory drug. The chronic alcohol consumption activates the hepatic inflammatory response associated to T-cell activation and overproduction of pro-inflammatory cytokines. The present work analyzed the anti-inflammatory effect of DEC on hepatic cells of alcoholic mice. Thirty-two male C57BL/6 mice were equally divided in the following groups: (a) control group (C), which received only water, (b) DEC-treated group, which received 50 mg/kg for 12 day (DEC50), (c) the alcoholic group (EtOH), submitted to only alcohol and (d) the alcohol-DEC treated group (EtOH50), submitted to alcohol plus DEC treatment after the induction of chronic alcoholism for 5 weeks. Biochemical analyses were performed and liver fragments were processed for light microscopy, transmission electron microscopy, immunohistochemical and western blot. The level of AST increased significantly in alcoholic group whereas a significant reduction of serum AST was detected in the EtOH50 group. Histological and ultrastructural analysis of alcoholic group showed evident hepatocellular damage, which was strikingly reduced in the alcoholic DEC-treated group. Immunohistochemistry results revealed highly expression of inflammatory markers as MDA, NF-κB, TNF-α, IL-6, VCAM and ICAM by the hepatic cells of the EtOH group; however no immunoreactivity for any of these cytokines was detected after DEC treatment. Western blot analyses showed increased MCP-1 and iNOS expression in EtOH group, which was significantly inhibited by DEC treatment. According to the present results, DEC can be a potential drug for the treatment of chronic inflammation induced by chronic alcoholism.