4-hydroxy-2-nonenal and Endotoxemia

Controlled mechanical ventilation and endotoxemia are associated with diaphragm muscle atrophy and dysfunction. Oxidative stress and activation of inflammatory pathways are involved in the pathogenesis of diaphragmatic dysfunction. Levosimendan, a cardiac inotrope, has been reported to possess anti-oxidative and anti-inflammatory properties. The aim of the present study was to investigate the effects of levosimendan on markers for diaphragm nitrosative and oxidative stress, inflammation and proteolysis in a mouse model of endotoxemia and mechanical ventilation.. Three groups were studied: (1) unventilated mice (CON, n =8), (2) mechanically ventilated endotoxemic mice (MV LPS, n =17) and (3) mechanically ventilated endotoxemic mice treated with levosimendan (MV LPS + L, n =17). Immediately after anesthesia (CON) or after 8 hours of mechanical ventilation, blood and diaphragm muscle were harvested for biochemical analysis.. Mechanical ventilation and endotoxemia increased expression of inducible nitric oxide synthase (iNOS) mRNA and cytokine levels of interleukin (IL)-1β, IL-6 and keratinocyte-derived chemokine, and decreased IL-10, in the diaphragm; however, they had no effect on protein nitrosylation and 4-hydroxy-2-nonenal protein concentrations. Levosimendan decreased nitrosylated proteins by 10% (P <0.05) and 4-hydroxy-2-nonenal protein concentrations by 13% (P <0.05), but it augmented the rise of iNOS mRNA by 47% (P <0.05). Levosimendan did not affect the inflammatory response in the diaphragm induced by mechanical ventilation and endotoxemia.. Mechanical ventilation in combination with endotoxemia results in systemic and diaphragmatic inflammation. Levosimendan partly decreased markers of nitrosative and oxidative stress, but did not affect the inflammatory response.

Topics: Aldehydes; Animals; Cardiotonic Agents; Chemokines; Diaphragm; Endotoxemia; Hydrazones; Inflammation; Interleukins; Mice, Inbred C57BL; Models, Animal; Nitric Oxide Synthase; Pyridazines; Respiration, Artificial; RNA, Messenger; Simendan

Bacterial endotoxin (lipopolysaccharide, LPS), at high concentration is responsible for sepsis, and neonatal mortality, however low concentration of LPS protected the pancreas against acute damage. The aim of this study was to investigate the effect of exposition of suckling rats to LPS on the course of acute pancreatitis at adult age. Suckling rat (30-40g) received intraperitoneal (i.p.) injection of saline (control) or LPS from Escherichia coli or Salmonella typhi (5, 10 or 15 mg/kg-day) during 5 consecutive days. Two months later these rats have been subjected to i.p. cearulein infusion (25 microg/kg) to produce caerulein-induced pancreatitis (CIP). The following parameters were tested: pancreatic weight and morphology, plasma amylase and lipase activities, interleukin 1beta (IL-1 beta), interleukin 6 (IL-6), and interleukin 10 (IL-10) plasma concentrations. Pancreatic concentration of superoxide dismutase (SOD) and lipid peroxidation products; malondialdehyde (MDA) and 4-hydroxynonenal (4-HNE) have been also measured. Caerulein infusion produced CIP in all animals tested, that was confirmed by histological examination. In the rats, which have been subjected in the neonatal period of life to LPS at doses 10 or 15 mg/kg-day x 5 days, all manifestations of CIP have been reduced. In these animals acute inflammatory infiltration of pancreatic tissue and pancreatic cell vacuolization have been significantly diminished. Also pancreatic weight, plasma lipase and alpha-amylase activities, as well as plasma concentrations of IL-1beta and IL-6 have been markedly decreased, whereas plasma anti-inflammatory IL-10 concentration was significantly increased in these animals as compared to the control rats, subjected in the infancy to saline injection instead of LPS. Caerulein-induced fall in pancreatic SOD concentration was reversed and accompanied by significant reduction of MDA + 4 HNE in the pancreatic tissue. The effects of LPS derived from E. coli or S. typhi were similar. Pretreatment of suckling rats with LPS at dose of 10 mg/kg-day x 5 days resulted in the most prominent attenuation of acute pancreatitis at adult age, whereas LPS at dose of 5 mg/kg-day x 5 days given to the neonatal rats failed to affect significantly acute pancreatitis induced in these animals 2 months later. We conclude that: 1/ Prolonged exposition of suckling rats to bacterial endotoxin attenuated acute pancreatitis induced in these animals at adult age. 2/ This effect could be related to

Topics: Acute Disease; Aldehydes; alpha-Amylases; Animals; Animals, Newborn; Ceruletide; Disease Models, Animal; Dose-Response Relationship, Drug; Endotoxemia; Interleukins; Lipase; Lipid Peroxidation; Lipopolysaccharides; Male; Malondialdehyde; Organ Size; Pancreas; Pancreatitis; Rats; Rats, Wistar; Severity of Illness Index; Superoxide Dismutase; Time Factors

We have developed a time-resolved fluoroimmunoassay (TR-FIA) for a lipid peroxide 4-hydroxynonenal (HNE), which is 100-fold more sensitive than conventional enzyme-linked immunosorbent assay (ELISA) and is an easier technique to use for a large number of samples without pre-treatment. By this assay, we found that a low dose of bacterial lipo-polysaccharide (LPS), injected intra-peritoneally (0.5 mg/kg), increased serum HNE level by 28-folds, with a peak at 20 min. LPS also increased HNE in vitro to a much higher level in the monocyte-enriched plasma than in the leukocyte-enriched plasma, with a peak at 10 min. The HNE production after LPS treatment was inhibited by apocynin, a specific NADPH oxidase inhibitor in vivo and in vitro, and to a lesser extent by dimethylsulfoxide a solvent for apocynin and a hydroxyl radical scavenger in vitro. These data suggest that monocyte NADPH oxidase is involved in the lipid peroxidation (HNE formation) in the LPS-challenged rat. This is the first clear demonstration of the link between an inflammatory stimulus and lipid peroxidation in the blood.

Topics: Aldehydes; Animals; Blotting, Western; Carrier Proteins; Endotoxemia; Fluoroimmunoassay; Humans; Leukocytes, Mononuclear; Lipid Peroxides; Lipopolysaccharides; Male; Malondialdehyde; Mice; NADPH Oxidases; Rats; Rats, Sprague-Dawley; Sensitivity and Specificity