ABSTRACT
We investigated the effect of a specific neurokinin-1 receptor (NK1R) antagonist, CP-96,345, on the regulation of the expression of adhesion molecules ICAM-1, VCAM-1, E-selectin, and P-selectin as well as leukocyte recruitment during acute pancreatitis (AP). AP was induced in male Balb/C mice by 10 consecutive hourly intraperitoneal injections of caerulein. In the treatment groups, CP-96,345 was administered at 2.5 mg/kg ip either 30 min before or 1 h after the first caerulein injection. Animals were killed, and the lungs and pancreas were isolated for RNA extraction and RT-PCR or for immunohistochemical staining. mRNA expression of the four adhesion molecules was upregulated in the pancreas during AP. Treatment with CP-96,345 effectively reduced the mRNA expression of P-selectin and E-selectin but not ICAM-1 and VCAM-1. In the lung, ICAM-1, E-selectin, and P-selectin mRNA expression increased during AP. Antagonist treatment suppressed this elevation. Similar expression patterns were seen in the immunohistochemical stainings. Intravital microscopy of the pancreatic microcirculation revealed the effect of CP-96,345 on leukocyte recruitment. The present study provides important information on the relationship between NK1R activation and the regulation of adhesion molecules. Also, this study points to the differential regulation of inflammation in the pancreas and lung with AP.
Subject(s)
Biphenyl Compounds/pharmacology , Intercellular Adhesion Molecule-1/biosynthesis , Pancreatitis/metabolism , Substance P/antagonists & inhibitors , Vascular Cell Adhesion Molecule-1/biosynthesis , Acute Disease , Amylases/blood , Animals , Cell Adhesion/drug effects , Ceruletide , Immunohistochemistry , Lung/physiopathology , Mice , Mice, Inbred BALB C , Neurokinin-1 Receptor Antagonists , Pancreas/physiopathology , Pancreatitis/chemically induced , Peroxidase/metabolismABSTRACT
Preprotachykinin-A (PPT-A) gene products substance P and neurokinin-A have been shown to play an important role in neurogenic inflammation. To investigate the role of PPT-A gene products in lung injury in sepsis, polymicrobial sepsis was induced by cecal ligation and puncture in PPT-A gene-deficient mice (PPT-A(-/-)) and the wild-type control mice (PPT-A(+/+)). PPT-A gene deletion significantly protected against mortality, delayed the onset of lethality, and improved the long-term survival following cecal ligation and puncture-induced sepsis. PPT-A(-/-) mice also had significantly attenuated inflammation and damage in the lungs. The data suggest that deletion of the PPT-A gene may have contributed to the disruption in recruitment of inflammatory cells resulting in protection against tissue damage, as in these mice the sepsis-associated increase in chemokine levels is significantly attenuated.
Subject(s)
Protein Precursors/genetics , Protein Precursors/metabolism , Respiratory Distress Syndrome/metabolism , Respiratory Distress Syndrome/microbiology , Sepsis/metabolism , Sepsis/microbiology , Tachykinins/genetics , Tachykinins/metabolism , Animals , Cell Proliferation , Cytokines/biosynthesis , Gene Deletion , Male , Mice , Mice, Knockout , Neutrophils/cytology , Neutrophils/metabolism , Protein Precursors/deficiency , Respiratory Distress Syndrome/complications , Respiratory Distress Syndrome/pathology , Sepsis/complications , Sepsis/pathology , Survival Rate , Tachykinins/deficiency , Time FactorsABSTRACT
Acute pancreatitis (AP) is a life-threatening condition that involves an acute inflammatory process in the pancreas. The involvement of tachykinins and neurokinin receptors in acute pancreatitis has been described only recently, despite their long-established role in inflammatory conditions. Among these, substance P (SP) is believed to play a central role in exacerbating the inflammatory process by acting through neurokinin-1 receptor (NK1R). Treatment with the NK1R antagonist, CP96,345, results in protection against caerulein-induced acute pancreatitis in mice. However, the mechanism by which NK1R and SP worsen the condition is still unclear. In the present study, we have investigated the effect of NK1R blockage on the expression of preprotachykinin genes and neurokinin receptors in acute pancreatitis. In the pancreas, CP96,345 treatment resulted in suppression of the elevation of SP concentration, preprotachykinin-A gene (PPT-A) mRNA expression, and NK1R mRNA and protein expression. In the lungs, the antagonist was found to suppress the increase in SP concentration, PPT-A mRNA expression and preprotachykinin-C gene (PPT-C) mRNA expression. However, the antagonist treatment further promoted the accumulation of pulmonary NK1R mRNA and protein expression. Neurokinin-2 receptor (NK2R) mRNA expression was not detected in normal pancreas. However, up-regulated expression of the mRNA for this receptor was observed during acute pancreatitis and treatment with CP96,345 further increased this expression. Pulmonary NK2R mRNA expression was found to be reduced during acute pancreatitis and CP96,345 treatment normalized this reduction. Neurokinin-3 receptor (NK3R) mRNA expression was absent in both pancreas and lung. These data have provided valuable information regarding the regulation of tachykinins and neurokinin receptors during acute pancreatitis.
Subject(s)
Anti-Inflammatory Agents, Non-Steroidal/pharmacology , Biphenyl Compounds/pharmacology , Pancreatitis/metabolism , Receptors, Neurokinin-1/metabolism , Tachykinins/metabolism , Acute Disease , Animals , Immunohistochemistry/methods , Lung/chemistry , Mice , Mice, Inbred BALB C , Models, Animal , Pancreas/chemistry , Protein Precursors/genetics , RNA, Messenger/analysis , Receptors, Neurokinin-1/analysis , Receptors, Neurokinin-1/genetics , Receptors, Neurokinin-2/genetics , Receptors, Neurokinin-3/genetics , Reverse Transcriptase Polymerase Chain Reaction , Substance P/analysis , Substance P/antagonists & inhibitors , Substance P/metabolism , Tachykinins/geneticsABSTRACT
Acute pancreatitis is a common clinical condition. It is a disease of variable severity in which some patients experience mild, self-limited attacks while others manifest a severe, highly morbid, and frequently lethal attack. The exact mechanisms by which diverse etiological factors induce an attack are still unclear. It is generally believed that the earliest events in acute pancreatitis occur within acinar cells. Acinar cell injury early in acute pancreatitis leads to a local inflammatory reaction. If this inflammatory reaction is marked, it leads to a systemic inflammatory response syndrome (SIRS). An excessive SIRS leads to distant organ damage and multiple organ dysfunction syndrome (MODS). MODS associated with acute pancreatitis is the primary cause of morbidity and mortality in this condition. Recent studies have established the role played by inflammatory mediators in the pathogenesis of acute pancreatitis and the resultant MODS. At the same time, recent research has demonstrated the importance of acinar cell death in the form of apoptosis and necrosis as a determinant of pancreatitis severity. In this review, we will discuss about our current understanding of the pathophysiology of acute pancreatitis.
Subject(s)
Pancreatitis/immunology , Pancreatitis/physiopathology , Acute Disease , Animals , Humans , Multiple Organ Failure/immunology , Multiple Organ Failure/physiopathologyABSTRACT
Hydrogen sulfide (H2S) is a naturally occurring gas with potent vasodilator activity. Cystathionine-gamma-lyase (CSE) and cystathionine-beta-synthase (CBS) utilize L-cysteine as substrate to form H2S. Of these two enzymes, cystathionine-gamma-lyase (CSE) is believed to be the key enzyme that forms H2S in the cardiovascular system. Whilst H2S has been reported to relax precontracted rat arteries in vitro and to lower blood pressure in the rat, its effect in an inflammatory condition such as acute pancreatitis has not previously been reported. In this paper, we report the presence of H2S synthesizing enzyme activity and CSE (as determined by mRNA signal) in the pancreas. Also, prophylactic, as well as therapeutic, treatment with the CSE inhibitor, DL-propargylglycine (PAG), significantly reduced the severity of caerulein-induced pancreatitis and associated lung injury, as determined by 1) hyperamylasemia [plasma amylase (U/L) (control, 1204+/-59); prophylactic treatment: placebo, 10635+/-305; PAG, 7904+/-495; therapeutic treatment: placebo, 10427+/-470; PAG, 7811+/-428; P<0.05 PAG c.f. placebo; n=24 animals in each group]; 2) neutrophil sequestration in the pancreas [pancreatic myeloperoxidase oxidase (MPO) activity (fold increase over control) (prophylactic treatment: placebo, 5.78+/-0.63; PAG, 2.97+/-0.39; therapeutic treatment: placebo, 5.48+/-0.52; PAG, 3.03+/-0.47; P<0.05 PAG c.f. placebo; n=24 animals in each group)]; 3) pancreatic acinar cell injury/necrosis; 4) lung MPO activity (fold increase over control) [prophylactic treatment: placebo, 1.99+/-0.16; PAG, 1.34+/-0.14; therapeutic treatment: placebo, 2.03+/-0.12; PAG, 1.41+/-0.97; P<0.05 PAG c.f. placebo; n=24 animals in each group]; and 5) histological evidence of lung injury. These effects of CSE blockade suggest an important proinflammatory role of H2S in regulating the severity of pancreatitis and associated lung injury and raise the possibility that H2S may exert similar activity in other forms of inflammation.
Subject(s)
Hydrogen Sulfide/metabolism , Lung Diseases/etiology , Pancreatitis/etiology , Acute Disease , Alkynes/pharmacology , Alkynes/therapeutic use , Amylases/blood , Animals , Cystathionine beta-Synthase/metabolism , Cystathionine gamma-Lyase/genetics , Cystathionine gamma-Lyase/metabolism , Cysteine/metabolism , Enzyme Inhibitors/pharmacology , Enzyme Inhibitors/therapeutic use , Glycine/analogs & derivatives , Glycine/pharmacology , Glycine/therapeutic use , Hydrogen Sulfide/blood , Lung Diseases/pathology , Lung Diseases/prevention & control , Male , Mice , Mice, Inbred BALB C , Pancreas/enzymology , Pancreatitis/pathology , Pancreatitis/prevention & control , Peroxidase/metabolism , Placebos , RNA, Messenger/analysis , Vasodilation/drug effectsABSTRACT
Earlier studies have shown that mice deficient in NK1 receptors or its ligand, substance P, are protected against acute pancreatitis and associated lung injury. In the current study, the protective effect of NK1 receptor blockage against acute pancreatitis and associated lung injury was investigated, using a specific receptor antagonist, CP-96345. Acute pancreatitis was induced in mice by intraperitoneal (i.p.) injections of caerulein. Substance P levels in plasma, pancreas, and lungs were found to be elevated in a caerulein dose-dependent manner. Mice treated with CP-96345, either prophylactically, or therapeutically, were protected against acute pancreatitis and associated lung injury as evident by attenuation in plasma amylase, pancreatic and pulmonary myeloperoxidase activities, and histological evidence of pancreatic and pulmonary injuries. Pulmonary microvascular permeability was also reduced as a result of CP-96345 treatment. These results point to a key role of NK1 receptors in acute pancreatitis and associated lung injury.
