ceruletide and Reperfusion-Injury

Melatonin, the main product of the pineal gland, is also released from the gastrointestinal endocrine-neurocrine (EE) cells. The concentrations of melatonin produced in the gut exceeds that originating from central nervous system. In spite of the presence of melatonin receptors in the pancreatic tissue little is known about the role of this indole in the pancreas. Our experimental studies have shown that exogenous melatonin, as well as this produced endogenously from its precursor; L-tryptophan, strongly stimulates pancreatic amylase secretion when given intraperitoneally, or into the gut lumen. This was accompanied by significant increases of CCK plasma level. Above pancreatostimulatory effects of luminal administration of melatonin, were completely reversed by bilateral vagotomy, capsaicin deactivation of sensory nerves or pretreatment of the rats with CCK1 receptor antagonist; tarazepide as well as serotonin antagonist; ketanserin. Melatonin, as well as its precursor; L-tryptophan, effectively protects the pancreas against the damage induced by caerulein overstimulation or ischemia/reperfusion. The beneficial effects of melatonin or L-tryptophan on acute pancreatitis could be related to the ability of melatonin to scavenge the free radicals, to activate antioxidative enzymes and to modulate the cytokine production.

Topics: Acute Disease; Amylases; Animals; Ceruletide; Cholecystokinin; Free Radical Scavengers; Gastrointestinal Tract; Melatonin; Pancreas; Pancreatitis; Receptor, Cholecystokinin A; Reperfusion Injury; Tryptophan

Necroptosis is a caspase-independent form of cell death that is triggered by activation of the receptor interacting serine/threonine kinase 3 (RIPK3) and phosphorylation of its pseudokinase substrate mixed lineage kinase-like (MLKL), which then translocates to membranes and promotes cell lysis. Activation of RIPK3 is regulated by the kinase RIPK1. Here we analyze the contribution of RIPK1, RIPK3, or MLKL to several mouse disease models. Loss of RIPK3 had no effect on lipopolysaccharide-induced sepsis, dextran sodium sulfate-induced colitis, cerulein-induced pancreatitis, hypoxia-induced cerebral edema, or the major cerebral artery occlusion stroke model. However, kidney ischemia-reperfusion injury, myocardial infarction, and systemic inflammation associated with A20 deficiency or high-dose tumor necrosis factor (TNF) were ameliorated by RIPK3 deficiency. Catalytically inactive RIPK1 was also beneficial in the kidney ischemia-reperfusion injury model, the high-dose TNF model, and in A20(-/-) mice. Interestingly, MLKL deficiency offered less protection in the kidney ischemia-reperfusion injury model and no benefit in A20(-/-) mice, consistent with necroptosis-independent functions for RIPK1 and RIPK3. Combined loss of RIPK3 (or MLKL) and caspase-8 largely prevented the cytokine storm, hypothermia, and morbidity induced by TNF, suggesting that the triggering event in this model is a combination of apoptosis and necroptosis. Tissue-specific RIPK3 deletion identified intestinal epithelial cells as the major target organ. Together these data emphasize that MLKL deficiency rather than RIPK1 inactivation or RIPK3 deficiency must be examined to implicate a role for necroptosis in disease.

Topics: Animals; Apoptosis; Ceruletide; Colitis; Dextran Sulfate; Disease Models, Animal; Female; Inflammation; Lipopolysaccharides; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Pancreatitis; Protein Kinases; Receptor-Interacting Protein Serine-Threonine Kinases; Reperfusion Injury; Sepsis; Systemic Inflammatory Response Syndrome; Tumor Necrosis Factor alpha-Induced Protein 3

Severe acute pancreatitis (SAP) is a serious systemic disease with a sustained high mortality rate. Extensive evidence has shown that gut barrier dysfunction plays a critical role in the pathophysiology of SAP.. Investigating the role of intestinal mucosa oxidative stress in gut barrier dysfunction of SAP.. Twenty-four BALB/c mice were randomly divided into two groups with twelve mice each group. The SAP group mice received six intraperitoneal injections of cerulein (50 µg/kg) at 1-hour intervals, then given one intraperitoneal injection of 10 mg/kg lipopolysaccharide (LPS from E. coli) for inducing SAP. Normal saline was given to the mice of control group. The animals of each group were averaged to two batches. Four and eight hours after the final injection, respectively, mice were anesthetized and blood and tissue samples were harvested for examination. The pathological changes of pancreas and gut were observed and scored. The serum levels of diamine oxidase (DAO), amylase and tumor necrosis factor-alpha (TNF-α) were measured. The contents of malondialdehyde (MDA) and reduced glutathione (GSH) and activity of superoxide dismutase (SOD) and xanthine oxidase (XO) in gut mucosa were detected. In gut mucosa, the caspase-3 activity was measured and the cell apoptosis and apoptosis index (AI) were determined by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay. The data were analyzed by ANOVA and t-test.. At four and eight hours after SAP induction, the SAP group mice had significantly higher pancreatic and gut pathological scores (p < 0.01) and increased serum levels of amylase (p < 0.05), DAO and TNF-α (p < 0.01) and increased MDA contents and XO activity of gut mucosa (p < 0.01) compared with those of control mice. There were significantly lower GSH contents (p < 0.05) and SOD activity (p < 0.01) of gut mucosa in the SAP mice. It was also observed that the gut mucosa cells of SAP mice had significantly higher caspase-3 activity and apoptosis index (p < 0.01).. In SAP, waterfall-style release of inflammatory factors such as TNF-α led to ischemia-reperfusion injury of gut mucosa which resulted in serious oxidative stress and activation of caspase-3 pathway and severe apoptosis of gut mucosa. Therefore, intestinal mucosal oxidative stress may play an important role in the mechanism of gut barrier dysfunction.

Topics: Acute Disease; Analysis of Variance; Animals; Apoptosis; Caspase 3; Ceruletide; Disease Models, Animal; In Situ Nick-End Labeling; Inflammation Mediators; Intestinal Mucosa; Male; Mice; Mice, Inbred BALB C; Oxidative Stress; Pancreatitis; Random Allocation; Reperfusion Injury; Severity of Illness Index; Tumor Necrosis Factor-alpha

Cerulenin has been shown to reduce body weight and hepatic steatosis in murine models of obesity by inhibiting fatty acid synthase (FAS). We have shown that attenuating intrahepatocyte lipid content diminished the sensitivity of ob/ob mice to ischemia/reperfusion injury and improved survival after liver transplantation. The mechanism of action is by inhibition of fatty acid metabolism by downregulating PPARalpha, as well as mitochondrial uncoupling protein 2 (UCP2), with a concomitant increase in ATP. A short treatment course of cerulenin prior to I/R injury is ideal for protection of steatotic livers. Cerulenin opens the potential for expanding the use of steatotic livers in transplantation.

Topics: Adenosine Triphosphate; Alanine Transaminase; Animals; Ceruletide; Fatty Acid Synthases; Fatty Acids; Fatty Liver; Graft Survival; Liver Transplantation; Male; Mice; Mice, Obese; Reperfusion Injury

Melatonin, a pineal secretory product, synthesized from l-tryptophan, has received increased attention because of its antioxidative and immunomodulatory properties. It has been detected in the gut and shown to protect the gastric mucosa, and liver from acute damage, but the role of melatonin in the protection of the pancreas against acute inflammation is not clear. The aim of this study was to investigate the effects of melatonin and its precursor, l-tryptophan, on caerulein-induced pancreatitis (CIP) and on ischemia/reperfusion (I/R)-provoked pancreatitis in rats. CIP was induced by subcutaneous infusion of caerulein to the rats (25 microg/kg). I/R was induced by clamping of the inferior splenic artery for 30 min followed by 2 hr of reperfusion. Melatonin (10, 25 or 50 mg/hr) or l-tryptophan (50, 100 or 250 mg/kg) was given as a bolus intraperitoneal (i.p.) injection 30 min prior to the onset of pancreatitis. CIP and I/R were confirmed by histologic examination and manifested by typical pancreatic edema, by an increase of plasma levels of amylase (by 500% in CIP and by 40% in I/R) and the pro-inflammatory tumor necrosis factor alpha (TNFalpha) (by 500%). Lipid peroxidation products such as malondialdehyde (MDA) and 4-hydroxynonenal (4-HNE), were increased several fold in the pancreas CIP and I/R, whereas pancreatic blood flow (PBF) was significantly reduced in these animals. Pretreatment of rats subjected to CIP or to I/R with melatonin (25 or 50 mg/kg i.p.) or l-tryptophan (100 or 250 mg/kg i.p.) significantly reduced pancreatic edema, plasma levels of amylase and TNFalpha and diminished pancreatic MDA + 4-HNE contents, while enhancing PBF, pancreatic integrity and plasma levels of the anti-inflammatory interleukin 10 (IL-10). This was accompanied by a marked and dose-dependent rise of plasma melatonin immunoreactivity. Gene expression of N-acetyl transferase, an enzyme involved in melatonin biosynthesis, was detected in the pancreas of normal rats and was significantly enhanced in the rats with CIP. We conclude that exogenous melatonin, and that produced from l-tryptophan, attenuates pancreatic damage induced by CIP or by I/R and this effect may be attributable to the reduction in lipid peroxidation and TNFalpha release combined with an increase of plasma anti-inflammatory IL-10 in rats with acute pancreatitis.

Topics: Adjuvants, Immunologic; Animals; Ceruletide; Interleukin-10; Ischemia; Male; Melatonin; Pancreas; Pancreatitis; Rats; Rats, Wistar; Reperfusion Injury; Tryptophan; Tumor Necrosis Factor-alpha