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Oxidative stress has a primary role in the pathogenesis of severe acute pancreatitis. Then, the antioxidant capacity is a critical factor in the progression of this disease. Serum paraoxonase-1 (PON1) is an esterase associated with high-density lipoprotein, which clinical interest resides in its ability to prevent or limit the lipid oxidation. The aim of this study was to investigate changes in PON1 activity in the early stages of acute pancreatitis and to find out if its alteration is related with the severity of the disease. To this purpose, we used an experimental model of taurocholate-induced mild and severe acute pancreatitis. Our results showed that serum activity and PON1 concentration decreased 18 h after the induction of a severe acute pancreatitis. In vitro analysis revealed that incubation with oxidized lipids obtained from pancreatitis samples results in the inactivation of the enzyme in a concentration-dependent manner. In addition to oxidative inactivation, we observed by Western blot, an immunoreactive band suggestive of proteolytic degradation of the enzyme, altogether indicating that during severe acute pancreatitis, there is a significant decrease in serum PON1 activity. This decrease is related with inactivation of the enzyme by oxidized lipids, probably followed by proteolytic degradation of the enzyme.

[Rationale]: Transplantation of stem cells has been proposed as a strategy for repair of lung fibrosis. Nevertheless, many studies have yielded controversial results that currently limit the potential use of these cells as an efficient treatment. Alveolar type II cells are the progenitor cells of the pulmonary epithelium and usually proliferate after epithelial cell injury. During lung fibrosis, however, the altered regeneration process leads to uncontrolled fibroblast proliferation. [Objectives]: To investigate whether intratracheal transplantation of isolated alveolar type II cells can halt and reverse the fibrotic process in an experimental model of bleomycin-induced lung fibrosis in rats. [Methods]: Lung fibrosis was induced in syngeneic female Lewis rats by a single intratracheal instillation of bleomycin (2.5 U/kg). Animals were transplanted with alveolar type II cells from male animals at a dose of 2.5 × 106 cells per animal 3, 7, and 15 days after endotracheal bleomycin instillation. Animals were killed 21 days after the induction of lung fibrosis. [Measurements and Main Results]: Lung fibrosis was assessed by histologic study anddetermination of hydroxyproline content. Engraftment of transplanted cells was measured by real-time polymerase chain reaction for the Y chromosome and by fluorescence in situ hybridization for the Y chromosome. Transplantation of alveolar type II cells into damaged lung 3, 7, or 15 days after bleomycin instillation led to reduced collagen deposition, and reduction in the severity of pulmonary fibrosis. [Conclusions]: This study demonstrates the potential role of alveolar type II cell transplantation in designing future therapies for lung fibrosis., Supported by grant FIS PI060679 from the Spanish Ministry of Health and by grant N-2005-79 from the Sociedad Española de Neumología y Cirugía Torácica (SEPAR).

A frequent complication of acute pancreatitis is the lung damage associated with the systemic inflammatory response. Although various pro-inflammatory mediators generated at both local and systemic levels have been identified, the pathogenic mechanisms of the disease are still poorly understood. In recent years, exosomes have emerged as a new intercellular communication system able to transfer encapsulated proteins and small RNAs and protect them from degradation. Using an experimental model of taurocholate-induced acute pancreatitis in rats, we aimed to evaluate the role of exosomes in the extent of the systemic inflammatory response. Induction of pancreatitis increased the concentration of circulating exosomes, which showed a different proteomic profile to those obtained from control animals. A series of tracking experiments using PKH26-stained exosomes revealed that circulating exosomes effectively reached the alveolar compartment and were internalized by macrophages. In vitro experiments revealed that exosomes obtained under inflammatory conditions activate and polarize these alveolar macrophages towards a pro-inflammatory phenotype. Interestingly, the proteomic analysis of circulating exosomes during acute pancreatitis suggested a multi-organ origin with a relevant role for the liver as a source of these vesicles. Tracking experiments also revealed that the liver retains the majority of exosomes from the peritoneal cavity. We conclude that exosomes are involved in the lung damage associated with experimental acute pancreatitis and could be relevant mediators in the systemic effects of pancreatitis. Copyright © 2016 Pathological Society of Great Britain and Ireland. Published by John WileySons, Ltd.

© 2015, IAP and EPC. Published by Elsevier India, a division of Reed Elsevier India Pvt. Ltd. All rights reserved. Background Necrosis of adipose tissue is a common complication of acute pancreatitis. The areas of steatonecrosis become a source of inflammatory mediators, including chemically modified fatty acids which could influence the progression of the systemic inflammation. In an experimental model of acute pancreatitis we analyzed the effects of lipids generated by two representative areas of adipose tissue on the switch to the M1 phenotype in macrophages. Methods Pancreatitis was induced in rats by intraductal administration of 5% taurocholate and after 6 h, lipids from retroperitoneal, mesenteric or epididymal adipose tissues were collected. Lipid uptake, phenotype polarization and the activation of PPARγ and NFκB were evaluated in macrophages treated with these lipids. Results After induction of pancreatitis, lipids from visceral adipose tissue promote the switch to an increased pro-inflammatory phenotype in macrophages. This effect is not related with a higher activation of NFκB but with an interfering effect on the activation of M2 phenotype. Conclusions During acute pancreatitis, lipids generated by some areas of adipose tissue interfere on the M2 polarization of macrophages, thus resulting in a more intense pro-inflammatory M1 response., This work was supported by the projects SAF 2009-07605 from Ministerio de Ciencia e Innovación, and FIS PI13/00019 from Instituto de Salud Carlos III. L.Bonjoch is supported by a grant from Generalitat de Catalunya (AGAUR, Grant FI DGR 2013)

P-selectin and circulating xanthine oxidase are involved in the process of neutrophil infiltration into the lung associated with acute pancreatitis. This study investigated the mediators that trigger the upregulation of P-selectin in this process. Pancreatitis was induced in rats by intraductal administration of 5% sodium taurocholate. P-selectin expression was measured using radiolabeled antibodies. Neutrophil infiltration and PAF levels were also evaluated. The role of superoxide radical, H(2)O(2), or the enzyme poly (ADP-ribose) synthetase (PARS) on these processes was determined in groups of animals treated with the corresponding inhibitors. Pancreatitis was associated with an increase in P-selectin expression in the lung. Inhibition of PARS or H(2)O(2) abrogated P-selectin upregulation, PAF generation, and neutrophil recruitment. Superoxide dismutation prevented neutrophil recruitment and PAF generation, but had no effect on P-selectin expression. We conclude that during acute pancreatitis, upregulation of P-selectin in the pulmonary endothelium is triggered by H(2)O(2) and PARS activity.

A beneficial effect of flavonoids in Cl(4)C-induced hepatoxicity in rats has been reported. In this communication we have evaluated the protective effect of astilbin, an active flavonoid isolated from a crude extract of Hymenaea martiana, as well as its action on liver arachidonate metabolism in Cl(4)C-treated rats. The following groups of rats were studied: Group I = controls; Group II = Astilbine-treated animals (40 mg/Kg); Group III = Cl(4)C-treated at 1 ml/kg; Group IV = Astilbine + ClC4 and Group V = Vitamine E (50 mg/Kg) + Cl(4)C-treated animals. Histological findings, superoxide dismutase activity, lipoperoxides and prostanoid profiling studies revealed that the hepatoprotective effect of astilbine was higher than that of vitamin E. Astilbine was capable to restore lipoperoxides and tissue prostanoids to basal values.

The effect of ischemic preconditioning on the intestine, as well the implication of nitric oxide and prostacyclin in this process has been evaluated. Thus, intestinal ischemia-reperfusion was induced in rats, and the protection conferred by previous preconditioning was evaluated. In addition, the effect of nitric oxide inhibition and the administration of nitric oxide were determined. Results show that the increases observed in LDH release after ischemia-reperfusion were prevented after preconditioning. Inhibition of nitric oxide synthesis abolished the protective effect of preconditioning, and nitric oxide administration replicated this effect. Also, an increased synthesis of nitric oxide has been detected after preconditioning. Increases in 6 keto PGF(1α) were independent of nitric oxide. Altogether indicates that preconditioning is triggered by an initial increase in nitric oxide synthesis., This work was supported by Grant 95/1009 from the Fondo de Investigaciones Sanitarias

The role of nitric oxide in lipoxygenase metabolism after a process of ischemia-reperfusion in pancreas transplantation has been evaluated in this study. Sprague-Dawley rats were randomized into three groups, as follows: Group I--Control animals not surgically manipulated; Group II.--Pancreas transplantation, after 12 h of organ preservation; Group III.--Same as II but with administration of NG-nitro-L-arginine methyl esther (a nitric oxide synthase inhibitor) (10 mg/Kg) prior to organ revascularization. The results show post-transplantation increases in leukotriene B4 and 12-hydroxyeicosatraenoic acid levels in pancreatic tissue. Nitric oxide synthase inhibition reversed the increases in 12-hydroxyeicosatetraenoic acid, but was unable to modify leukotriene B4 increases suggesting the existence of a direct effect of nitric oxide on the 12-lipoxygenase metabolism in pancreas transplantation.

The role of liver in the respiratory dysfunction associated with acute pancreatitis has been evaluated. For this purpose, an experimental necrohemorrhagic pancreatitis was induced in rats by intraductal administration of 3.5% sodium taurocholate. Additionally, a portocaval shunt was performed before induction of acute pancreatitis to prevent the initial passage through the liver of substances released by the pancreas. Twelve hours after the induction of pancreatitis, increases in lung prostacyclin and thromboxane B2 synthesis, decreased lung superoxide dismutase activity, and increases in plasma phospholipase A2 activity were found. In addition, inflammatory injury was evidenced in lung by histopathological analysis. The portocaval shunt was able to prevent the metabolic changes and ameliorate the inflammatory process in the lung, suggesting that the liver plays an active role in the systemic inflammatory response to acute pancreatitis.

[Objective]: To evaluate the generation of halogenated fatty acids in the areas of fat necrosis during acute pancreatitis and to evaluate the effects of these molecules on the ensuing inflammatory process. [Background]: Lipid mediators derived from adipose tissue have been implicated in the progression of acute pancreatitis, although their precise role remains unknown. [Methods]: Acute pancreatitis was induced in rats by intraductal infusion of 3.5% sodium taurocholate. Fatty acid chlorohydrins (FA-Cl) were measured in adipose tissue, ascitic fluid, and plasma by mass spectrometry. Chlorohydrins were also instilled in the rats' peritoneal cavity, and their effects on peritoneal macrophages activation and in systemic inflammation were evaluated. Finally, they have also been measured in plasma from human patients with acute pancreatitis. [Results]: Induced acute pancreatitis results in a substantial release not only of free fatty acids but also of the chlorohydrins of both oleic and linoleic acids from adipose tissue. In plasma, only the chlorohydrin of oleic acid was detected. Administration of 250-μM lipid chlorohydrins, which is the concentration found in ascitic fluid, induces the expression of TNFα and interleukin-1β in peritoneal macrophages and increases the systemic inflammatory response in pancreatitis. Finally, increased concentrations of oleic acid chlorohydrin have been found in plasma of human patients with pancreatitis. [Conclusions]: During acute pancreatitis, adipose tissue release FA-Cl, which exacerbate the systemic inflammatory response. Copyright © 2013 by Lippincott Williams & Wilkins.

The role of eicosanoid metabolism and its relationship with nitric oxide production in the ischemia-reperfusion associated with pancreas transplantation in the rat is explored in this study. Twenty-six male Sprague-Dawley rats were randomized into 3 groups, as follows: group 1, control animals not surgically manipulated; group 2, pancreas transplantation, after 12 hr of organ preservation in University of Wisconsin solution; group 3, same as group 2 but with administration of NG-nitro-L-arginine methyl ester (a nitric oxide synthase inhibitor) (10 mg/kg) before organ revascularization. The results show posttransplantation increases in edema and in 6-keto-prostaglandin F1 alpha (x1.9), thromboxane B2 (x4), and prostaglandin E2 (x5) levels in pancreatic tissue. Nitric oxide synthase inhibition reversed the increases in edema and eicosanoid production, which suggests that eicosanoid generation in the recipient rat would be mediated, in part, through a nitric oxide-dependent mechanism.

The role of nitric oxide in eicosanoid and oxygen-free radical production in the early stages of sodium taurocholate-induced acute necrotizing pancreatitis has been studied. Male Wistar rats were divided into three groups: group I: control group, a volume of 0.1 ml/100 g body wt saline solution was injected at low pressure in the pancreatic duct; group II: acute pancreatitis was induced by administration of 3.5% sodium taurocholate; and group III: intravenous administration of NG-nitro-L-arginine methyl esther (a nitric oxide synthase inhibitor) 5 min before induction of acute pancreatitis as stated for group II. At 5 and 60 min after induction of pancreatitis, blood and pancreas tissue samples were taken for assays. Increases in 6-keto PGF1 alpha, TXB2, PGE2, PGF2 alpha, and 12-HETE were observed in the pancreatic tissue. Lipoperoxidation was also enhanced and remained unaltered after nitric oxide inhibition. The fact that nitric oxide synthase inhibition could only reverse the increases in 6-keto PGF1 alpha and TXB2 levels indicates that in acute pancreatitis endothelial and platelet eicosanoid generation is mediated through an nitric oxide-dependent mechanism. In contrast, nitric oxide appears to be not related with oxygen free radical damage associated with acute pancreatitis.

Oxygen free radicals (OFR) are postulated to play a role in the pathogenesis of acute pancreatitis. The aim of this work was to examine the role of xanthine oxidase in the generation of OFR and the activity of the endogenous defense mechanisms as reflected by pancreatic superoxide dismutase (SOD) activity in a model of edematous pancreatitis induced in rats by administration of cerulein at supramaximal doses, as well as in necrohemorrhagic model induced by intraductal administration of sodium taurocholate. Comparison between these two models of pancreatitis suggests important differences in origin and importance in the evolution of injury. In necrohemorrhagic pancreatitis OFR can be produced by xanthine oxidase activity probably associated to cell death. By contrast, in cerulein induced pancreatitis, other sources of oxygen free radicals, such as inflammatory cells, can be of more importance.

Core and organ temperatures in the rat have been found to be subject to regular periodic oscillations (with a frequency of ca 12 cycles per day, i.e. 143 mu Hz) within set limits, by using a chronic thermocouple implant procedure. These cycles consisted of consecutive warming (the temperature increased steadily) and cooling periods (the temperature decreased regularly). There were sustained temperature differences between several tissues and that of the aortic blood (core temperature), higher for brown adipose tissue, kidney and liver, and lower for muscle, white adipose tissue and skin. Organ blood flows and cardiac output were measured by a radioactive microsphere retention method applied to unanaesthetized rats. Blood flow measurements were done on unaware rats (see Methods), during either the warming or cooling phases. During the warming phases, there was a higher blood flow across the brown adipose tissue, kidney and skin, with a cardiac output about twice that found in the cooling periods. The haemodynamic changes observed, as well as the organ temperature differences observed with respect to the blood, suggest that periodic changes in blood flow are an essential part of the operation of the thermogenic system.

Systemic prostacyclin and thromboxane A2 production in rat experimental acute pancreatitis has been evaluated by measuring the urinary excretion of the 2,3-dinor 6-keto prostaglandin F1 alpha and 2,3-dinor thromboxane B2, respectively. Acute pancreatitis was induced by intraductal administration of 4.5% sodium taurocholate (0.1 ml/100 mg body weight) and intravenous cerulein perfusion (5 micrograms/kg/hr) for 6 hr, respectively. Urinary excretion of 2,3-dinor 6-keto prostaglandin F1 alpha and 2,3-dinor thromboxane B2 were much more important in sodium taurocholate- than in cerulein-induced acute pancreatitis. These data confirm an altered prostacyclin and thromboxane metabolism occurring in experimental acute pancreatitis. Phospholipase A2 activity and the effect of gabexate mesilate on the arachidonate metabolism were also evaluated.

Pulmonary macrophages exist in two different anatomical compartments in the lower respiratory tract: alveolar macrophages in the alveoli and interstitial macrophages in the interstitium. Depending on the micro-environmental stimulation, macrophages follow different activation pathways. According to their inflammatory response pattern, activated macrophages have been characterized as pro-inflammatory (M1), wound-healing (M2a) and regulatory (M2b). Since acute pancreatitis occurs in parallel with acute lung injury, the profile of the different macrophage subpopulations could be relevant in the progression of the disease. The activation of lung alveolar and interstitial macrophages was assessed in an experimental model of severe acute pancreatitis induced in rats by intraductal infusion of 3.5% sodium taurocholate. Alveolar and interstitial macrophages were obtained and the expression of markers of different activations was evaluated. Activation of nuclear factors PPARγ and NF-κB, which are involved in the acquisition of different phenoytpes, was also measured. Alveolar macrophages acquired an early M1 phenotype characterized by the expression of inflammatory cytokines and NF-κB activation. In contrast, interstitial macrophages followed the inhibitory M2b pathway. In these macrophages, PPARγ became activated and the anti-inflammatory cytokine IL-10 was expressed. These results suggest that alveolar and interstitial macrophages play different roles in acute lung injury associated with acute pancreatitis. Alveolar macrophages promote an early inflammatory response, whereas interstitial macrophages help resolve inflammation.

Obesity and lipid metabolism are associated with the severity of acute pancreatitis. Fat necrosis appears in the severe acute pancreatitis as a consequence of the release of lipolytic enzymes, but its potential role on the progression of the disease is unclear. In this study, we have examined the role of white adipose tissue as a source of inflammatory mediators that can promote systemic inflammation during experimental taurocholate-induced acute pancreatitis in rats. The inflammatory status and the expression of TNFalpha, iNOS, adiponectin and IL-10 were determined in necrotic and non-necrotic areas of adipose tissue. Samples of adipose tissue were also used to induce the activation of macrophages in vitro. Finally, the release of TNFalpha to mesenterial vessels surrounded by necrotic or non-necrotic fat was evaluated in ex vivo perfused mesenterium. A strong inflammatory infiltrate was observed in the border between necrotic and non-necrotic areas of adipose tissue. In these areas, high expression of TNFalpha and iNOS and a reduced expression of IL-10 were observed, while adiponectin showed only a moderate increase. Necrotic fat strongly activates peritoneal macrophages in vitro. Mesenterial areas with fat necrosis release to the vascular vessels significantly increased amounts of TNFalpha when compared to vessels without necrosis. Altogether, these results indicate that adipose tissue inflammation is a process secondary to acute pancreatitis but also contributes to the generation of mediators potentially involved in the induction of the systemic inflammatory response. In particular, the areas of fat necrosis are important sources of inflammatory mediators.

Prostacyclin metabolism in rat acute pancreatitis was evaluated by measuring the tissue levels of 6-keto-prostaglandin F 1α (6-keto-PGF 1α ) and the urinary excretion of 2, 3-dinor 6-keto-PGF 1α . Acute pancreatitis was induced by i.v. cerulein perfusion and was confirmed by the pancreas enzyme changes and the histological findings. Significantly enhanced tissue and urinary prostacyclin levels were found in acute pancreatitis rats, when compared to the controls. Concomitantly, an enhanced tissue phospholipase A 2 (PLA 2 ) activity was also found. These data show the importance of 2, 3-dinor PGF 1α as an inflammatory marker in cerulein-induced pancreatitis.

[Background]: Pancreatitis-associated ascitic fluid (PAAF) plays a critical role in the pathogenesis of acute pancreatitis. Taking into consideration that damaged pancreas exudates high concentrations of lipolytic enzymes in the peritoneal cavity, large amounts of lipid metabolism derived products could occur in PAAF. In this study, we have examined the involvement of the lipid fraction of PAAF generated in the early stages of experimental acute pancreatitis., [Methods]: Pancreatitis was induced in rats by intraductal administration of 5% sodium taurocholate. After three hours, PAAF was collected and its lipid fraction was obtained. Lipid composition and levels of lipid peroxidation were measured. Toxicity was evaluated by measuring the effects of PAAF lipid fraction on cell viability of hepatic and macrophage cell lines. In vivo effects on the liver were also evaluated. Effects on the inflammatory response were determined by measuring the levels of NFkB activation, the effect on the inhibitory activity of 15-deoxy-PGJ2 and the possible interference on PPARgamma activation., [Results]: High concentrations of oxidized free fatty acids were detected in PAAF. Besides the direct cell toxicity, the PAAF-derived lipid extract interfered with the anti-inflammatory pathway mediated by PPARgamma. Addition of this lipid extract to macrophage cell cultures had no direct effect on NFkB activation, but abolished the inhibitory activity of endogenous PPARgamma agonists such as 15-deoxy-PGJ2., [Conclusions]: Oxidized free fatty acids present in PAAF interfere with the endogenous regulatory mechanism of the inflammatory response, thus promoting an exacerbation of macrophage activation in acute pancreatitis., unding: This work was supported by the projects SAF2006-08449, CSIC 2006-2-0I-013 and FIS PI050599. Ciberhd is funded by the Instituto de Salud Carlos III.

The aim was to assess whether induction of ventilator-induced lung injury (VILI) in one lung triggers a concomitant inflammatory response in the normally ventilated contralateral lung. To this end, a differential ventilator was used in 6 rats. One lung was normally ventilated (3.5 ml/kg b.w.) and the contralateral lung was overstretched (15 ml/kg b.w.). Six control rats were normally ventilated (3.5 ml/kg b.w. each lung). After 3 h, edema and gene expression of MIP-2 in the lung, and plasma and liver TNF-α were assessed. Overexpression of MIP-2 and edema were found in the overventilated lung but not in the normally ventilated contralateral lung. No detectable levels of circulating and liver TNF-α were detected. These data do not support the hypothesis of an early positive feedback in the lung inflammation during the mechanical ventilation.

Pancreatitis-associated protein (PAP) was discovered in the pancreatic juice of rats with acute pancreatitis. PAP is a 16 kDa secretory protein structurally related to the C-type lectins although classical lectin-related function has not been reported yet. Then, it was demonstrated that PAP expression may be activated in some tissues in a constitutive or injury- and inflammation-induced manner. More recently, it has been found that PAP acts as an anti-inflammatory factor in vitro and in vivo. PAP expression can be induced by several pro- and anti-inflammatory cytokines and by itself through a JAK/STAT3-dependent pathway. PAP is able to activate the expression of the anti-inflammatory factor SOCS3 through the JAK/STAT3-dependent pathway. The JAK/STAT3/ SOCS3 pathway seems to be a common point between PAP and several cytokines. Therefore, it is reasonable to propose that PAP is a new anti-inflammatory cytokine. © 2007 The WJG Press. All rights reserved.

Background: The angiotensin system has a role in the pathogenesis of pulmonary fibrosis. This study examines the antifibrotic effect of losartan, an angiotensin II type 1 receptor antagonist, in bleomycin induced lung fibrosis and its possible implication in the regulation of prostaglandin E2 (PGE2) synthesis and cyclooxygenase-2 (COX-2) expression. Methods: Rats were given a single intratracheal instillation of bleomycin (2.5 U/kg). Losartan (50 mg/kg/day) was administrated orally starting one day before induction of lung fibrosis and continuing to the conclusion of each experiment. Results: Losartan reduced the inflammation induced by bleomycin, as indicated by lower myeloperoxidase activity and protein content in the bronchoalveolar lavage fluid. Collagen deposition induced by bleomycin was inhibited by losartan, as shown by a reduction in the hydroxyproline content and the amelioration of morphological changes. PGE2 levels were lower in fibrotic lungs than in normal lungs. Losartan significantly increased PGE 2 levels at both 3 and 15 days. A reduction in COX-2 expression by bleomycin was seen at 3 days which was relieved by losartan. Conclusions: The antifibrotic effect of losartan appears to be mediated by its ability to stimulate the production of PGE2. Losartan, which is already widely used clinically, could be assessed as a new treatment in lung fibrosis., This study was supported in part by grants from Hospital Clínic de Barcelona (Premi Fi de Residencia, 2003), SEPAR 2003, FIS 02/0186, FUCAP 2004, Red Respira (Fondo de Investigaciones Sanitarias, V-2003-REDC11D-0), and I+D SAF2003-04450

The liver is a source of systemic proinflammatory mediators in acute pancreatitis. We have investigated the effects of blood from the pancreas and intestine in liver activation and lung inflammation during early stages of experimental acute pancreatitis in a rat model. A portosystemic shunt and a mesosystemic shunt were created to prevent the passage of blood coming from the pancreas and the intestine, respectively, to the liver. Pancreatitis was induced by retrograde injection of 5% sodium taurocholate into the biliopancreatic duct. After 3 hours, the inflammatory process in the lung and intestine, plasma levels of tumor necrosis factor (TNF)-α and their soluble receptor, and mRNA expression of inflammatory mediators in the lung were evaluated. Portocaval shunting of blood prevented the inflammatory process in the lung, an increase in plasma TNF-α concentration, and the expression of TNF-α, interleukin (IL)-1β, and heat-shock protein (HSP)-72 in the lung, but had no effect on plasma levels of soluble TNF-α receptor or on expression of inducible nitric oxide synthase (iNOS) and macrophage inflammatory protein (MIP)-2 in the lung. In contrast, mesocaval shunting of blood did not modify any of the parameters evaluated. Pancreatic blood, but not intestinal blood, plays a key role in liver activation during experimental acute pancreatitis., Supported by the 2001 Research Grant Program of the Hospital Clinic, University of Barcelona, and by FIS grant PI020286, and a grant from Institut d'Investigacions Biomèdiques August Pi i Sunyer (S.G.

The Toxic Oil Syndrome (TOS) was a toxic epidemic disease, related to the consumption of rapeseed oil denatured with aniline that affected more than 20,000 people in Spain and resulted in more than 330 deaths after its sudden appearance in 1981. It has been reported that the fatty acid esters of 3-(N-phenylamino)-1,2-propanediol (PAP) have shown a strong association with TOS. These PAP-esters could be absorbed and metabolized in a similar way than phospholipids. This is of interest because some products of phospholipid metabolism are important mediators in downstream pathways involved in the regulation of different nuclear factors. In particular, phospholipase D activity is involved in the activation of c-fos. Thus, we have investigated the effect of different PAP-esters in the induction of c-fos in lung fibroblasts. Results indicate that PAP-esters rapidly induced the expression of c-fos in a dose-dependent manner. In addition, both butanol and propranolol prevent this induction pointing to the involvement of phospholipase D in this activation. These results suggest that deregulation of some nuclear factors such as AP-1 could be involved in the pathogenesis of TOS. © 2004 Elsevier Ireland Ltd. All rights reserved.

To design, implement, and test a selective lung ventilator for setting a rat model of unilateral ventilator-induced lung injury (VILI).Interventional animal study in a university laboratory for animal research.Anesthetized and paralyzed male Wistar rats.A selective ventilator designed to apply varying tidal volume, PEEP, and breathing gas to each lung of the rat was implemented and evaluated. Five control animals were ventilated at 7 ml/kg (3.5 ml/kg each lung). Unilateral VILI was induced in six animals subjected to selective ventilation (3.5 ml/kg in one lung and 15 ml/kg in the other lung). After 3 h of ventilation the animals were killed and the lungs excised.Lung edema was assessed by means of the ratio between wet and dry lung weights. No significant differences were found in lungs of control animals (5.16+/-0.22 and 4.96+/-0.25), but the W/D ratio in the over ventilated lung (8.98+/-3.80) was significantly greater than that in the normally ventilated lung (4.76+/-0.15), indicating selective induction of lung edema by over stretch.This selective ventilator can be implemented into a rat model of unilateral VILI to gain further insight into the mechanisms of pulmonary injury induced by different ventilatory strategies.

During the early stages of acute pancreatitis, acute respiratory distress syndrome often occurs. This is associated with the release of proinflammatory mediators into the blood, but it remains unclear why these mediators induce inflammation especially in the lung. One of the first events occurring during the progression of acute pancreatitis is the induction of P-selectin expression in the endothelial cells of the lung. This expression has been associated with the generation of superoxide radicals by circulating xanthine oxidase. Because this enzyme needs molecular oxygen to perform the reaction, we have hypothesized that oxygen present in the alveolar space favors the generation of free radicals by xanthine oxidase and explains why P-selectin is expressed only in the lung. For this purpose, we evaluated the progression of the inflammatory process in rats with induced acute pancreatitis and one lung breathing nitrogen while the other lung continued breathing air. Acute pancreatitis was induced by intraductal administration of taurocholate and myeloperoxidase; P-selectin expression was measured 3 h after induction. Results indicated that, in the absence of oxygen in the alveolar space, the xanthine oxidase-dependent P-selectin expression did not occur and lung inflammation was significantly reduced. © 2004 Elsevier Inc. All rights reserved., This work was supported by FIS Grant PI020286, Red GIRA-ISCIII-G03/63, and Red Respira-ISCIII-CO3/11; S. Granell is recipient of an IDIBAPS predoctoral grant

Clinical and experimental studies have shown increased concentrations of TNF-α and its soluble receptors in serum of patients with acute pancreatitis. In this work, we have investigated the time-course of TNF-α and its soluble receptors during taurocholate-induced acute pancreatitis. In addition, since TNF-α itself could mediate the shedding of its receptors, we have assessed the effect of inhibiting TNF-α production on the release of soluble TNF-α receptors in experimental acute pancreatitis. Our results indicate that soluble receptors are released in the early stages of the disease and this increase is concomitant with the release of TNF-α, which is mainly bound to specific proteins. The increased concentrations of its receptors strongly suggest that they could be these binding proteins. Inhibition of TNF-α generation with pentoxifylline abrogated the shedding of sTNF-αR1, but had no effect on sTNF-αR2. This finding suggests that the shedding of sTNF-αR1 is induced by TNF-α itself, but in the case of sTNF-αR2, the shedding appears to be induced by another mechanism. © 2003 Elsevier Ltd. All rights reserved., This work was supported by grants GV01-137 from Generalitat Valenciana, 1FD1997-1616 from Ministerio de Ciencia y Tecnologı́a and 01/0949 FIS form Ministerio de Sanidad y Consumo; S. Granell was supported by a grant from IDIBAPS

This article is available from: http://www.biomedcentral.com/1471-230X/4/1, [Background] Xanthine oxidoreductase has been proposed to play a role in the development of local and systemic effects of acute pancreatitis. Under physiologic conditions, the enzyme exists mainly as xanthine dehydrogenase (XDH) but can be converted by proteolytic cleavage to its superoxide-generating form xanthine oxidase (XOD). In addition to its intracellular location XDH/XOD is also associated to the polysaccharide chains of proteoglycans on the external endothelial cell membrane. In the early stages of acute pancreatitis, this enzyme seems to be arising from its mobilization from the gastrointestinal endothelial cell surface. Taking into account the ability of α-amylase to hydrolyze the internal α-1,4 linkages of polysaccharides, we wanted to elucidate the involvement of α-amylase in XDH/XOD mobilization from the gastrointestinal endothelial cell surface and the relevance of the ascitic fluid (AF) as the source of α-amylase in experimental acute pancreatitis., [Methods] Acute pancreatitis was induced in male Wistar rats by intraductal administration of 5% sodium taurocholate. In another experimental group 3000 U/Kg α-amylase was i.v. administered. The concentrations of XDH, XOD and α- amylase in plasma and AF and myeloperoxidase (MPO) in lung have been evaluated. In additional experiments, the effect of peritoneal lavage and the absorption of α-amylase present in the AF by an isolated intestine have been determined., [Results] Similar increase in XDH+XOD activity in plasma was observed after induction of acute pancreatitis and after i.v. administration of α-amylase. Nevertheless, the conversion from XDH to XOD was only observed in the pancreatitis group. Lung inflammation measured as MPO activity was observed only in the pancreatitis group. In addition peritoneal lavage prevented the increase in α-amylase and XDH+XOD in plasma after induction of pancreatitis. Finally, it was observed that α-amylase is absorbed from the AF by the intestine., [Conclusions] During the early stages of acute pancreatitis, α-amylase absorbed from AF through the gastrointestinal tract could interfere with the binding of XDH/XOD attached to glycoproteins of the endothelial cells. Proteolytic enzymes convert XDH into its oxidase form promoting an increase in circulating XOD that has been reported to be one of the mechanisms involved in the triggering of the systemic inflammatory process., This work has been supported by FISss grants 01/0949 and PI020286; S.Granell and M.Genesca are recipients of IDIBAPS predoctoral grants.

Javier Pereda et al., Objective: To assess the effects of inhibiting both tumor necrosis factor (TNF)-α production and xanthine oxidase activity on the inflammatory response, mitogen-activated protein kinase (MAPK) activation and mortality in necrotizing acute pancreatitis in rats. Summary Background Data: Pancreatic injury triggers 2 major pathways involved in the systemic effects of severe acute pancreatitis: pro-inflammatory cytokines and oxidative stress. Methods: Pancreatitis was induced by intraductal infusion of 3.5% sodium taurocholate. We examined whether treatment with oxypurinol, a specific inhibitor of xanthine oxidase, and/or pentoxifylline, an inhibitor of TNF-α production, affects pancreatic damage, ascites, lung inflammation, and MAPK phosphorylation. Results: Oxypurinol prevented p38 phosphorylation in the pancreas and partially avoided the rise in lung myeloperoxidase activity. Pentoxifylline prevented erk 1/2 and JNK phosphorylation in the pancreas, and it partially reduced ascites and the rise in lung myeloperoxidase activity. Combined treatment with oxypurinol and pentoxifylline almost completely abolished ascites, MAPK phosphorylation in the pancreas, and the increase in lung myeloperoxidase activity. Histology revealed a reduction in pancreatic and lung damage. These changes were associated with a significant improvement of survival. Conclusions: Simultaneous inhibition of TNF-α production and xanthine oxidase activity greatly reduced local and systemic inflammatory response in acute pancreatitis and decreased mortality rate. These effects were associated with blockade of the 3 major MAPKs., This work was supported by the following Grants: Grant GV01-137 from Generalitat Valenciana, 1FD1997-1616 from Ministerio de Ciencia y Tecnología, and the 1rst Grant for research on exocrine pancreas from Solvay Pharma-Spain funded by Solvay Pharma and sponsored by ANEP to J. S.; and Grant BFI 2001-2849 from CICYT to J.V.

p8 is a transcription cofactor whose expression is strongly and rapidly activated in pancreatic acinar cells during the acute phase of pancreatitis. A p8-deficient mouse strain was generated as a tool to investigate its function. Upon induction of acute pancreatitis, myeloperoxidase activity in pancreas and serum concentrations of amylase and lipase were much higher and pancreatic lesions more severe in p8-deficient mice than in wild-type, indicating that p8 expression decreased pancreatic sensitivity to pancreatitis induction. The protective mechanism might involve the pancreatitis-associated protein (PAP I), whose strong induction during pancreatitis is p8-dependent, because administration of anti-PAP I antibodies to rats increased pancreatic inflammation during pancreatitis. In addition, 100 ng/ml PAP I in the culture medium of macrophages prevented their activation by tumor necrosis factor α, strongly suggesting that PAP I was an anti-inflammatory factor. Finally, PAP I was able to inhibit NFκB activation by tumor necrosis factor α, in macrophages and in the AR42J pancreatic acinar cell line. In conclusion, p8 improves pancreatic resistance to inducers of acute pancreatitis by a mechanism implicating the expression of the anti-inflammatory protein PAP I., This work was supported by grants from Association pour le Recherche sur le Cancer and Ligue Contre le Cancer (to J. L. I.) and Fonds de Investigaciones Sanitories PI020286 (to D. C.)

Oxidative stress is involved in the pathophysiology of inflammatory airway diseases including asthma; therefore, antioxidants might be of clinical benefit in asthma treatment. In the present study, the effects of N-acetylcysteine on sensitised brown Norway rats were examined. N-Acetylcysteine (3 mmol kg body weight(-1) administered orally) was given daily for 1 week before challenge and various antigen-induced pulmonary responses were studied. Antigen exposure increased lipid peroxidation in bronchoalveolar lavage fluid (BALF) and oxidised glutathione levels in lung tissue 2 h after challenge. Lung nuclear transcription factor-KB-binding activity was increased 2 h after challenge, and BALF tumour necrosis factor-alpha and inducible nitric oxide synthase expression in lungs peaked 4 h after challenge. Expression of intercellular adhesion molecule-1 and mucin MUC5AC was also increased 4 h after challenge. These changes in oxidant status, transcription factor activation, and inflammatory cytokine and gene expression were reduced by N-acetylcysteine. This thiol did not affect the immediate bronchospasm reaction to antigen in anaesthetised rats but inhibited airways hyperresponsiveness to 5-hydroxytryptamine and the augmented eosinophil numbers in BALF, which appear 24 h after exposure of conscious rats to antigen aerosol, and abolished antigen-induced extravasation of Evans blue into BALF. These results indicate that oral N-acetylcysteine exerts an antioxidant protective effect and attenuates pulmonary inflammation in experimental asthma.

The pancreatitis-associated protein (PAP) is a pancreatic stress protein overexpressed during acute pancreatitis, a disease often accompanied by lung inflammation. We investigated whether PAP was involved in the occurrence of this remote complication of pancreatitis and whether the liver might be implicated in the process. PAP was injected into the vena cava of rats (40 or 400 micro g/kg body weight). For comparison, pancreatitis was induced in rats by intraductal administration of sodium taurocholate. Three hours later, parameters of inflammation and mRNA concentrations of TNFalpha, P-selectin, heat shock protein (HSP)-70, and extracellular superoxide dismutase (EC-SOD) were monitored in lung and liver. Significant increases in P-selectin expression, neutrophil infiltration, and oxidative stress revealed that PAP treatment induced lung inflammation in rats and exacerbated inflammation in animals with pancreatitis. Plasma TNFalpha level was increased and TNFalpha mRNA was strongly overexpressed in liver, with concomitant activation of NF-kappaB; in situ hybridization revealed that TNFalpha overexpression was mainly located to hepatocytes. Lung inflammation induced by PAP could be prevented by injection of anti-TNFalpha antibodies. It was concluded that, during pancreatitis, PAP released by the pancreas could mediate lung inflammation through induction of hepatic TNFalpha expression and subsequent increase in circulating TNFalpha.

Objective: To evaluate the effect of low molecular weight heparin on plasma xanthine oxidase concentrations and lung inflammatory response during acute pancreatitis. Design: Randomized, controlled trial. Setting: Experimental laboratory. Subjects: Male Wistar rats. Interventions: Acute pancreatitis was induced by intraductal administration of 5% sodium taurocholate. Low molecular weight heparin (0, 30, 90, or 300 units/kg) was administered immediately after induction of pancreatitis. Measurements and Main Results: Lipase and xanthine oxidase plasma concentrations were measured 3 hrs after pancreatitis induction. Expression of P-selectin messenger RNA and myeloperoxidase activity as a marker of neutrophil infiltration were determined in the lung. An increase in xanthine oxidase plasma concentrations was observed during pancreatitis. Administration of heparin also increased plasma xanthine oxidase activity in both control and pancreatitis animals. Measures of xanthine oxidase present in the endothelial surface indicate that during pancreatitis, the enzyme is released from the gastrointestinal endothelium. By contrast, heparin mobilizes xanthine oxidase from almost all organs evaluated. Neutrophil infiltration was increased in the lung during pancreatitis. Heparin administration further increased, in a dose-dependent manner, myeloperoxidase activity and P-selectin expression in the lung in animals with pancreatitis. By contrast, in control animals, heparin had no effect on myeloperoxidase activity and did not induce P-selectin up-regulation. Conclusion: During acute pancreatitis, heparin administration might mobilize xanthine oxidase attached to endothelial cells, originating a free radical-generating system in the circulation that would trigger an inflammatory response in the lung.

Background: A number of adhesion molecules are involved in the process of neutrophil infiltration into the lung. P-selectin is one of these neutrophil-endothelial cell adhesion molecules. A study was undertaken to examine the involvement of P-selectin in the development of bleomycin induced inflammation and the ability of N-acetyl-L-cysteine to reduce the potential expression of this selectin in rats. Methods: N-acetyl-L-cysteine (3 mmol/kg po) was administered daily for seven days prior to bleomycin administration (2.5 U/kg). The kinetics of P-selectin expression and the effect of N-acetyl-L-cysteine after bleomycin treatment were measured using radiolabelled antibodies. P-selectin localisation was evaluated by immunohistochemistry and neutrophil infiltration was assessed by myeloperoxidase activity. Results: Bleomycin administration resulted in an upregulation of P-selectin at 1 hour, returning to baseline at 3 hours. Myeloperoxidase activity showed a significant increase at 6 hours after bleomycin administration that lasted for 3 days. N-acetyl-L-cysteine treatment completely prevented these increases. Conclusion: Upregulation of P-selectin in the lung is associated with neutrophil recruitment in response to bleomycin. The beneficial effect of N-acetyl-L-cysteine on bleomycin induced lung injury may be explained in part by the prevention of neutrophil recruitment in the inflammatory stage of the disease., This work was supported by grant 1FD97-1143 from the European Union (Regional Development Funds, FEDER) and grant FIS98/1367 (Spanish Ministry of Health)

Toxic Oil Syndrome (TOS) was an epidemic disease related to the consumption of rapeseed oil denatured with aniline that made its sudden appearance in Spain in 1981. The fatty acid esters of 3-(N-phenylamino)-1,2-propanedioI (PAP), which is a chemical class of by-products resulting from the reaction of aniline with oil components, have shown a strong association with TOS-related oils. These compounds also show some structural similarities to platelet-activating factor (PAF). In search of a toxic agent that could explain the widespread systemic effects observed in TOS patients, we investigated the intestinal absorption and biotransformation of the different PAP esters found in TOS-related oil samples and the possible pathophysiological effect of these mediators and their metabolic products if acting as PAF analogs. Results indicate that PAP esters are absorbed in the gastrointestinal tract and are distributed and stored in different organs, particularly in the liver and brown adipose tissue. PAP in these organs showed different patterns of fatty acids, indicating the ability of the gastrointestinal tract to modify the fatty acid composition of the parent PAP. Thus, the fatty acid profile of the PAP esters found in intestine appears to be related to the type of oil used as vehicle. Some of these PAP esters, when a long acyl chain was present in the sn-1 position of the molecule, showed an inhibitory effect on the PAF synthesis. This is an important observation in line with the systemic nature of the disease., This work has been supported by FISss grant 96/1815-SAT; E. Folch is recipient of an IDIBAPS predoctoral grant

Background. Experimental studies have shown that 21-aminosteroids (21- A) are powerful inhibitors of superoxide-mediated iron-dependent lipid peroxidation. This study was aimed at determining how far the blocking effect of one of these substances (lazaroid U74389G) on lipid peroxidation protects intestinal grafts morphologically and biologically in a heterotopic transplant model (SBT) in rats. Animals and methods. Heterotopic LEW were performed using Ringer lactate (4°C) as preservation solution. In Group 1 (n = 7) the donor and recipient animals received 3 and 6 mg/kg of the 21-A U74389G, respectively. Group 2 (n = 7) received the same doses of the vehicle of the drug. Sham group underwent only a laparotomy. Bacterial translocation (BT) was determined in mesenteric lymph nodes (MLN), liver (L), and spleen (S) 60 min after reperfusion. Tissue myeloperoxidase (MPO), malondialdehyde (MDA), and percentage conversion xanthine dehydrogenase/xanthine oxidase (XD/XO) were also determined in the ileal graft. Histological damage was graded according to Park's classification. Results. Tissue MDA (nmol/mg prot) was significantly lower in Group 1 (0.53 ± 0.09) than in Group 2 (3.66 ± 1, P < 0.05) and showed levels similar to those of the sham-operated group (0.40 ± 0.05). Injury grades were also significantly different in both study groups (Group 1, 0-1; Group 2, 2-3, P < 0.05). BT (log CFU/g tissue) in Group 1 were MLN, 0; L, 0.36; and S, 0. In Group 2, MLN, 1.07; L, 0.81; and S, 1.49 (P < 0.05 in MLN). Increase in MPO activity (U/g prot) in comparison with sham-operated animals was similar in the two study groups (Group 1, 1.49 ± 0.58; Group 2, 1.22 ± 0.46; Sham, 0.34 ± 0.37 (P < 0.05 1,2 vs sham). Conversion of XD to XO was unaffected by the supplementation of the drug. Conclusion. 21A U74389G inhibits lipid peroxidation, protects intestinal graft, and reduces BT after heterotopic SBT in rats., This work was supported in part by Pharmacia-Upjohn Company 18. Squadrito, F., Altavilla, D., and Ammendiola, L. et al. Improved (Kalamazoo, MI)

In the present investigation we studied the concerted role of superoxide anion, platelet activating factor (PAF) and leukotriene B4 (LTB4) in the mechanism that results in polymorphonuclear leucocyte accumulation induced by oxygen free radicals in rat pancreas. This was done by comparing the effects of a PAF antagonist (BN-52021), a LTB4 inhibitor (MK-886) and superoxide dismutase (SOD) in a experimental rat model of inflammation elicited by the oxygen free radicals induced via infusion of xanthine/xanthine oxidase. Also, the effect of independent LTB4 infusion has been studied. The results show that increases in polymorphonuclear cell infiltration (evaluated by tissue histology), myeloperoxidase and LTB4 levels induced in pancreas by infusion of xanthine/xanthine oxidase were abolished by the administration of either the PAF antagonist, the LTB4 inhibitor, or SOD. The fact that BN-52021 could prevent neutrophil recruitment and LTB4 synthesis suggests that PAF is a necessary step for subsequent LTB4 synthesis and polymorphonuclear leucocyte accumulation., This work was supported by grant: 95/1009. Fondo de Investigaciones Sanitarias

The concerted involvement of both NO and endothelin in the protective effect of preconditioning against hepatic ischemia-reperfusion induced injury has been evaluated in this study. Thus hepatic ischemia-reperfusion or preconditioning plus ischemia-reperfusion was induced in rats and the effect of nitric oxide administration or inhibition with addition of the endothelin antagonist Bosentan was evaluated. Results show that the increases in plasma GPT release after ischemia-reperfusion were prevented after preconditioning. Inhibition of nitric oxide abolished the effect of preconditioning, addition of the endothelin antagonist abolished the injurious effect of NO inhibition. Also, increased synthesis of endothelin has been detected after ischemia-reperfusion, and addition of NO or preconditioning prevented this increase, suggesting that increases of NO inhibit endothelin synthesis. Altogether this indicates that hepatic preconditioning is mediated by the inhibitory action of nitric oxide on endothelin levels.

The effect of verapamil administration on the changes of prostanoid synthesis, and on free radical production associated with acute pancreatitis, has been evaluated. A necrohemorrhagic model of pancreatitis was induced in Wistar rats by intraductal administration of sodium taurocholate (3.5%). This model is associated with initial increases in prostanoid synthesis and peroxidative damage. Verapamil, administered before pancreatitis induction, prevented initial increases in 6-keto prostaglandin F 1α (PGF 1α ) and thromboxane B 2 (TXB 2 ) but had no effect on PGF 2α or PGE 2 or on lipoperoxidative damage. These results indicate that verapamil administration prevents the increases in pancreatic vasoactive prostanoids (TXB 2 and 6-keto PGF 1α ) without affecting the increased levels of PGE 2 and PGF 2α and has no effect on oxygen free radical production in the initial stages of experimental acute pancreatitis.

The effect of bradykinin on nitric oxide generation and eicosanoid production in the early stage of an experimental model of acute necrotizing pancreatitis induced by sodium taurocholate has been evaluated. We have compared the effect of administering a long-acting bradykinin antagonist, HOE 140, and an inhibitor of nitric oxide synthase, NG-nitro- l -arginine methyl esther l ,-NAME) on pancreatic prostanoid synthesis. Plasma lipase levels were increased after acute pancreatitis induction, and reduced after HOE 140 or l ,-NAME administration. Nitric oxide production and thromboxane B2 levels were increased after pancreatitis induction and the increases were reduced by l -NAME or HOE 140 administration. In contrast, increased prostacyclin production, reflected as 6-keto-PGF1α levels, was not modified by l -NAME or HOE 140. Bradykinin seems to be involved in nitric oxide and thromboxane synthesis during the initial phases of acute necrohemorrhagic pancreatitis.

We have studied the liver 15-hydroxyeicosatetraenoic acid (15-HETE) and leukotriene B4 (LTB4) levels in streptozotocin- (ST)-induced diabetes in rats using liquid chromatography and radioimmunological techniques. Diabetic rats showed significant alterations of liver lipoxygenase metabolites when compared to controls. These 15-HETE and LTB4 increases were concomitant with raised levels of plasma and tissue thromboxane B2 (TXB2) and also urinary 2,3-dinor-TXB2 in plasma and urine, respectively. These changes confirm an activation of 5- and 15-lipoxygenase in the liver 3 days after i.p. ST administration.

The aim of this work is to establish a relationship between prostanoids and oxygen free radicals in the early stages of acute pancreatitis induced by sodium taurocholate and to study the possible cytoprotective effects of exogenous prostaglandin administration. Tissue prostanoid production (6-keto-prostaglandin F1 alpha, thromboxane B2, and prostaglandin E2) was studied after induction of an acute pancreatitis by intraductal administration of 3.5% sodium taurocholate (0.1 ml/100 mg). The effect of previous administrations of 16,16-dimethyl prostaglandin E2 (0.5 microgram/kg), indomethacin (20 mg/kg), or superoxide dismutase (13 mg/kg) was evaluated. Early pancreatitis induced significant increases of the three prostanoid levels as soon as 5 min after taurocholate administration. The administration of 16,16-dimethyl prostaglandin E2 was able to maintain the tissue prostanoid production at basal levels while superoxide dismutase treatment only partially prevented the increase of 6-keto-prostaglandin F1 alpha. On the other hand, indomethacin pretreatment, as expected, prevented the taurocholate-induced early prostanoid biosynthesis but increased the mortality, suggesting that endogenous prostanoids play a role in cellular defense mechanisms. The effect of superoxide dismutase suggests that oxygen free radicals are responsible, in part, for prostanoid enhanced biosynthesis in the earlier stages of necrohemorrhagic pancreatitis.

This paper describes the application of a combined high-performance liquid chromatography and radioimmunological assay method for the measurement of prostaglandins E1(PGE1) and E2(PGE2). Samples were acidified to pH 3.15, extracted twice with ethyl acetate and further processed through C18 solid-phase extraction cartridges. After HPLC purification, PGE1 and PGE2 were measured by radioimmunological techniques. The limit of detection for PGE1 was 3.9 pg/ml and the intra-assay relative standard deviation was 7.8% for n = 5. The accuracy of the assay procedure was also verified. The method has been applied to the determination of PGE1 and PGE2 in embryo incubates from 10-day pregnant rats.

Oxygen free radicals and prostaglandins are implicated in the pathophysiology of acute pancreatitis, although their mechanisms of action remain unclear. We have studied the effect of administration of exogenous 16,16-dimethyl prostaglandin E2 and superoxide dismutase on oxygen free radical production in acute pancreatitis. For this purpose, five experimental rat groups were studied: group I, control; group II, sodium taurocholate-induced acute pancreatitis; group III, same as group II but with previous administration of 16,16-dimethyl prostaglandin E2; group IV, same as group II but with previous administration of indomethacin; and group V, same as group II but with previous administration of superoxide dismutase. In sodium taurocholate-treated rats, xanthine dehydrogenase is completely converted to xanthine oxidase within the first 5 min with subsequent oxygen free radical production while in 16,16-dimethyl prostaglandin E2-treated rats this enzyme transformation does not occur. In the superoxide dismutase-treated group xanthine oxidase activation is partially prevented. These data suggest that xanthine oxidase is the main source of oxygen free radicals, which contribute to extending the cellular damage in sodium taurocholate-induced acute pancreatitis.

Several studies have reported that prostanoids are involved in many of the physiopathological mechanisms underlying acute pancreatitis but their precise role in this disease remains to be established. The objective of this work is to evaluate the variation of local tissue production of prostanoids and lipoxygenase metabolites of arachidonic acid in acute pancreas inflammation induced by intraductal administration of 3.5 % sodium taurocholate (0.1 ml/100 mg body weight) in rats. Pancreatic tissue levels of leukotriene B 4 (LTB 4 ), 15 hydroxyeicosatetraenoic acid (15-HETE), 6-keto prostaglandin F 1α (6-keto PGF 1α ), thromboxane B 2 (TXB 2 ) and prostaglandin E 2 (PGE 2 ) were determined by HPLC-RIA techniques at 5 and 60 minutes after induction of acute pancreatitis (AP). Prostanoids increased significantly at 5 minutes and LTB 4 and 15-HETE at 60 minutes. These data confirm that the prostanoid imbalance could be considered as an early specific response of the pancreas to the inflammatory events characteristic of induced AP while the altered levels of the lipoxygenase products (LTB 4 and 15-HETE) would be more of a nonspecific organ response associated to the high cellular infiltration rate and necrosis observed in the late phases of acute pancreatitis.

The rhythms of aortic core temperature and overall heat production in Wistar rats was analyzed by using long series of recordings of temperature obtained from implanted thermocouple probes and heat release values from a chamber calorimeter. There was a very high degree of repetitiveness in the presentation of actual heat rhythms, with high cross-correlation values ascertained wit paired periodograms. No differences were observed between heat production between male and female adult rats. The cross-correlation for temperature gave similar figures. The cross-correlation study between heat production and aortic core temperature in the same animals was significant and showed a displacement of about 30 minutes between heat release and aortic core temperature. The analysis of heat production showed a strong predominance of rhythms with periods of 24 hours (frequencies11.6 microHz) or more; other rhythms detected (of roughly the same relative importance) had periods of 8 or 2.2 hours (35 or 126 microHz, respectively). The analysis of aortic core temperature showed a smaller quantitative contribution of the 8 or 2.2 hours (35 or 126 microHz) rhythms, with other harmonic rhythms interspersed (5.1 and 4.0 hours, i.e. 54 and 69 microHz). The proportion of 'noise' or cycles lower than 30 minutes (550 microHz) was higher in internal temperature than in the actual release of heat. The results are in agreement with the existence of a basic period of about 130 minutes (126 microHz) of warming/cooling of the blood, with a number of other harmonic rhythms superimposed upon the basic circadian rhythm.

To study the activation of pancreatic and pulmonary mast cells and the effect of mast cell inhibition on the activation of peritoneal and alveolar macrophages during acute pancreatitis. METHODS: Pancreatitis was induced by intraductal infusion of 5% sodium taurodeoxycholate in rats. The mast cell inhibitor cromolyn was administered intraperitoneally (i.p.) 30 min before pancreatitis induction. The pancreatic and pulmonary tissue damage was evaluated histologically and mast cells and their state of activation were evaluated. Peritoneal and alveolar macrophages were obtained and the expression of tumor necrosis factor α was determined. Myeloperoxidase activity was measured to evaluate the effect of mast cell inhibition on the progression of the inflammatory process. Finally, the effect of plasma on cultured mast cells or macrophages was evaluated in vitro. RESULTS: The mast cell stabilizer significantly reduced inflammation in the pancreas and lung and the activation of alveolar macrophages but had no effect on peritoneal macrophages. Mast cell degranulation was observed in the pancreas during pancreatitis but no changes were observed in the lung. Plasma from rats with pancreatitis could activate alveolar macrophages but did not induce degranulation of mast cells in vitro. CONCLUSION: Pancreatic mast cells play an important role in triggering the local and systemic inflammatory response in the early stages of acute pancreatitis. In contrast, lung mast cells are not directly involved in the inflammatory response related to pancreatic damage., Supported by The Project SAF2006-08449 and a grant from Fundación para la Investigación del Hospital General Universitario de Alicante; Inmaculada Lopez-Font has a Juan de la Cierva contract supported by the Spanish Ministry of Science and Innovation.

Small thermocouple sensors were surgically implanted in the liver, kidney, hind leg muscle, interscapular brown adipose tissue, small and large intestines, dorso-lumbar internal side of the skin, periovaric adipose tissue and the lower aorta of Wistar rats. The aortic temperature was taken as core temperature. The sensors allowed continuous long-term monitoring of the temperatures of these organs. A period of 18 hours of food deprivation resulted in an overall decrease of mean core and organ temperature, brown adipose tissue temperature dropping to values lower than those of the aorta in the fed state. Liver, kidney and small intestine maintained higher temperatures than the aorta both in fed and starved states. Refeeding overshot the core temperature with increases in most organs versus both the fed and food-deprived situations. The results are concordant with an active role of brown adipose tissue in dietary induced thermogenesis. Three days of food deprivation did not alter the basic circadian rhythm of core temperatures in the rat kept at 22 degrees C, whereas it did modulate both nightly maximum and diurnal minimum temperatures to much lower settings than either in the fed or refed situations. The rat adapts to starvation by decreasing core and organ temperatures and widening the amplitude of the daily temperature cycle.

A modification of the usual microsphere injection method is presented which is appropriate for rat lung blood flow measurement. The injection of microspheres into the abdominal cava vein, together with the sampling of a reference flow from the right ventricle, allowed to calculate pulmonary blood flows in the same range than the cardiac output. The differences between the two figures (about 30%) are attributed to arterio-venous shunts. The tissue distribution of the microspheres bypassing the lung capillary beds agree with this interpretation.

This study was carried out to investigate the proportion of the 6-keto prostaglandin F1 alpha (6-keto PGF1 alpha) and thromboxane B2 (TXB2) alteration that is due to ischemia in pancreas transplantation against the proportion due to reperfusion. For this purpose, Lewis rats were divided in three experimental groups: Group I = Control, Group II = Donor pancreas subjected to 15 minutes of cold ischemia, Group III = Same as group II but pancreas were transplanted to the recipient individual and then subjected to reperfusion. The results indicate that increases in pancreas 6-keto PGF1 alpha occur as a consequence of cold ischemia while TXB2 remains unchanged. When blood flow was restored, 6-keto PGF1 alpha remained unchanged compared to the ischemic group while pancreatic levels of TXB2 were significantly increased. These results suggest a different induction of prostanoid metabolism during ischemia and reperfusion in pancreatic tissue.