Ethyl pyruvate supplemented in drinking water ameliorates experimental nonalcoholic steatohepatitis.

Inflammation and oxidative stress play a significant role in the pathogenesis of nonalcoholic steatohepatitis (NASH). Ethyl pyruvate (EP) is a novel anti-inflammatory agent and a potent reactive oxygen species (ROS) scavenger. Therefore, EP supplemented in drinking water may alleviate experimental NASH in this study (even though 0.3% of EP cannot attenuate the simple non-aggressive fatty liver). The methionine-choline-deficient (MCD) diet was given to the C57BL/6 male mice for 3 weeks to induce NASH. The NASH animals were randomized into 3 treatment groups: animals in the MCD alone group were treated with normal drinking water alone; animals in the delayed EP group were given 3% (v/v) of EP supplemented in normal drinking water, the treatment started 10 days after MCD diet feeding; animals in the early EP therapy group were treated the same as the delayed EP group except that EP treatment started the same day when MCD diet was given; the control mice were fed with normal chow and treated with normal drinking water (n = 10 for each group). Compared to MCD group with normal drinking water, early EP treatment significantly decreased serum ALT and improved NASH histopathology; delayed EP therapy only attenuated NASH in 50% (5/10) of the animals. The beneficial effects were associated with decreased hepatic TNF-a and IL-6 mRNA expression on early 5 days, inhibited NF-kB activation, reduced liver tissue malondialdehyde levels, and decreased intestinal bacterial translocation (BT). In conclusion: EP supplemented in drinking water attenuates experimental NASH.

Ethyl pyruvate ameliorates liver injury secondary to severe acute pancreatitis.

BACKGROUND: Ethyl pyruvate (EP) is capable of significantly decreasing serum alanine aminotransferase and reducing hepatic necrosis in a murine model of severe acute pancreatitis (SAP); however, the working mechanism is still unclear. This study aims to elucidate the underlying mechanism of EP solution ameliorating SAP-induced liver injury and provide a new therapeutic agent to treat liver injury. MATERIALS AND METHODS: Acute necrotizing pancreatitis was induced in C57Bl/6 male mice by feeding the animals a choline-deficient diet supplemented with 0.5% ethionine for 24 h; then the animals were challenged with 7 hourly 50 mug/kg cerulein i.p. injections and a single i.p. injection of Escherichia coli lipopolysaccharide (4 mg/kg). Two hours after the injection of lipopolysaccharide, 40 mg/kg EP, the same volume of Ringers lactate solution (RLS), or saline solution were i.p. injected to animals of EP, RLS, and control groups every 6 h for a total 48-h period. RESULTS: When mice were treated with EP, hepatic mRNA expression of tumor necrosis factor-alpha, interleukin-6, inducible nitric oxide synthase, and cyclooxygenase-2 was significantly lower than that in pancreatitis mice treated with RLS. Compared to RLS treatment, treatment with EP significantly decreased the number of inflammatory cell infiltration and markedly inhibited hepatic nuclear factor-kappa B DNA binding; EP therapy dramatically inhibited high motility group B1 release from inflamed hepatic tissue and significantly decreased the concentration of hepatic tissue malondialdehyde, an oxidative stress parameter. EP treatment also significantly improved body circulating blood volume. CONCLUSION: EP is a potent anti-inflammatory and anti-oxidative agent to ameliorate hepatic local inflammatory response and resultantly decreases liver injury secondary to SAP.

The ethyl pyruvate analogues, diethyl oxaloproprionate, 2-acetamidoacrylate, and methyl-2-acetamidoacrylate, exhibit anti-inflammatory properties in vivo and/or in vitro.

Ethyl pyruvate (EP) is a simple aliphatic ester derived from the endogenous metabolite, pyruvic acid. EP has been shown to decrease the expression of various pro-inflammatory mediators, including nitric oxide (NO*), tumor necrosis factor (TNF), cyclooxygenase-2, and interleukin (IL)-6, in a variety of in vitro and in vivo model systems. In an effort to better understand the chemical features that might explain the anti-inflammatory properties of EP, we screened 15 commercially available compounds for cytoprotective or anti-inflammatory effects using two in vitro assay systems: TNF and NO* production by lipopolysaccharide (LPS)-stimulated RAW 264.7 murine macrophage-like cells and changes in the permeability of Caco-2 human enterocyte-like monolayers stimulated with a cocktail of pro-inflammatory cytokines called cytomix (1000U/ml IFN-gamma plus 10ng/ml TNF-alpha plus 1ng/ml IL-1beta). Two compounds, namely diethyl oxaloproprionate (DEOP) and 2-acetamidoacrylate (2AA), demonstrated consistent anti-inflammatory or cytoprotective pharmacological properties in this screening process. Treatment of mice with either of these compounds ameliorated LPS-induced ileal mucosal hyperpermeability to the fluorescent probe, fluorescein isothiocyanate-labeled dextran (average molecular mass 4kDa), and bacterial translocation to mesenteric lymph nodes. Treatment with either of these compounds also improved survival in mice challenged with a lethal dose of LPS. Finally, in a study that compared 2AA to its methyl ester, we showed that methyl-2-acetamidoacrylate is at least 100-fold more potent than the parent carboxylate as an inhibitor of LPS-induced NO* production by RAW 264.7 cells. Collectively, these data are consistent with the view that anti-inflammatory activity is demonstrable for a number of compounds that either incorporate an olefinic linkage conjugated to a carbonyl moiety or are capable of undergoing tautomeric rearrangement to form such a structure. Moreover, our findings suggest that esters with these general characteristics, perhaps because of their greater lipophilicity or electrophilicity, are more potent anti-inflammatory agents than are the parent carboxylates.

Ethyl pyruvate ameliorates distant organ injury in a murine model of acute necrotizing pancreatitis.

OBJECTIVE: Ethyl pyruvate has been shown to be an effective anti-inflammatory agent in a variety of in vitro and in vivo model systems. Herein, we used a murine model of acute pancreatitis to compare the effects of treatment with either Ringer's lactate solution or ethyl pyruvate solution on several physiologic and biochemical variables related to disease severity. DESIGN: Experimental animal study. SETTING: University laboratory. SUBJECTS: C57Bl/6 mice. INTERVENTIONS: Pancreatitis was induced by feeding the animals a choline-deficient diet supplemented with 0.5% ethionine for 24 hrs and then challenging the animals with seven hourly 50 microg/kg intraperitoneal injections of cerulein and a single intraperitoneal injection of Escherichia coli lipopolysaccharide (4 mg/kg). MEASUREMENTS AND MAIN RESULTS: When mice were treated with ethyl pyruvate (40 mg/kg intraperitoneally every 6 hrs for 48 hrs) instead of Ringer's lactate solution starting 2 hrs after the injection of lipopolysaccharide, long-term survival was improved from one of ten to six of ten (p =.057). When mice were treated with a 40 mg/kg dose of ethyl pyruvate just before the first dose of cerulein and then injected with a second 40 mg/kg dose 6 hrs later, serum concentrations of alanine aminotransferase measured 10 hrs after the first cerulein dose were significantly lower than in mice with pancreatitis treated with Ringer's lactate solution. In this model of acute pancreatitis, the same dosing regimen for ethyl pyruvate also ameliorated bacterial translocation to mesenteric lymph nodes and leakage of fluorescein isothiocyanate-labeled albumin from blood into bronchoalveolar lavage fluid. Treatment with ethyl pyruvate decreased pancreatic expression of tumor necrosis factor and interleukin-6 messenger RNA and nuclear factor-kappaB DNA binding in nuclear extracts prepared from pancreatic tissue. CONCLUSION: Treatment with ethyl pyruvate ameliorated the local inflammatory response and decreased local and distant organ injury in a murine model of necrotizing pancreatitis.