Biomedical subjects

R Tomaszewska

Publications and source records attributed to R Tomaszewska.

At least 19 recordsLinked to original sources

PubMed2006

Effect of ischemic preconditioning on pancreatic regeneration and pancreatic expression of vascular endothelial growth factor and platelet-derived growth factor-A in ischemia/reperfusion-induced pancreatitis.

UNLABELLED: Ischemic preconditioning has been shown to protect several organs from ischemia/reperfusion-induced injury. In the pancreas, protective effect of ischemic preconditioning has been shown against pancreatitis evoked by ischemia/reperfusion, as well as by caerulein. However, the effect of ischemic preconditioning on the course of acute pancreatic is unclear. The aim of our study was to evaluate the influence of ischemic preconditioning on pancreatic regeneration and pancreatic presence of platelet-derived growth factor-A (PDGF-A) and vascular endothelial growth factor (VEGF) in the course of ischemia/reperfusion-induced pancreatitis. METHODS: In male Wistar rats, ischemic preconditioning of the pancreas was performed by short-term clamping of celiac artery (twice for 5 min with 5 min interval). Acute pancreatitis was induced by clamping of inferior splenic artery for 30 min followed by reperfusion. Rats were sacrificed 1, 5, 12 h or 1, 2, 3, 5, 7, 9 and 21 days after the start of reperfusion. Severity of acute pancreatitis and pancreatic regeneration were determined by biochemical and morphological examination, expression of growth factors was determined by immunohistochemical analysis. RESULTS: In ischemia/reperfusion-induced pancreatitis, the pancreatic damage reached the maximal range between the first and second day of reperfusion, and was followed by subsequent pancreatic regeneration. Ischemic preconditioning alone caused mild passing pancreatic damage and an increase in plasma concentration of pro-inflammatory interleukin-1 and anti-inflammatory interleukin-10. Ischemic preconditioning applied before ischemia/reperfusion-induced pancreatitis reduced morphological and biochemical signs of the pancreatitis-evoked pancreatic damage and accelerated pancreatic regeneration. This effect was associated with improvement of pancreatic blood flow. Ischemic preconditioning, ischemia/reperfusion-induced pancreatitis and their combination increased the presence of VEGF in acinar and islet cells, and immunostaining for PDGF-A in blood vessels. This effect was maximally pronounced after combination of ischemic preconditioning plus pancreatitis and occurred earlier than after pancreatitis alone. CONCLUSIONS: Ischemic preconditioning reduces pancreatic damage and accelerates pancreatic healing in the course of ischemia/reperfusion-induced pancreatitis. This effect is associated with the increase in plasma concentration of anti-inflammatory interleukin-10, improvement of pancreatic blood flow and alteration of pancreatic immunohistochemical expression of PDGF-A and VEGF.

Animals↗

PubMed2006

Cannabinoids in acute gastric damage and pancreatitis.

UNLABELLED: Recent studies have shown that stimulation of cannabinoid 1 (CB1) receptor reduces the area of ischemic myocardial necrosis and affects activity of the digestive tract. The aim of the present study was to check whether the administration of CB1 receptor agonist or antagonist affects the stress-induced gastric ulceration and development of edematous pancreatitis. METHODS: Experiments were performed on rats. Gastric lesions were induced by water immersion and restrain stress (WRS). Acute pancreatitis was induced by cerulein. Prior to WRS or before and during cerulein administration, a natural endogenous ligand for CB1 receptor, anandamide was administered intraperitoneally at the dose of 0.8, 1.5 or 3.0 micromol/kg. A synthetic CB1 receptor antagonist, AM 251 (ALEXIS(R) Biochemicals) was administrated at the dose of 4 micromol/kg i.p. alone or in combination with anandamide at the dose of 1.5 micromol/kg. RESULTS: Administration of anandamide reduced gastric lesions and this effect was associated with am increase in gastric mucosal blood flow and mucosal DNA synthesis; whereas serum level of pro-inflammatory interleukin-1 beta was reduced. Treatment with AM 251 aggravated gastric damage and reversed protective effect of anandamide administration. Opposite effect was observed in the pancreas. Administration of anandamide increased dose-dependently the severity of pancreatitis. In histological examination, we observed an increase in pancreatic edema and inflammatory infiltration. Also, treatment with anandamide augmented the pancreatitis-induced increase in serum level of lipase, amylase, poly-C ribonuclease, and pro-inflammatory interleukin-1 beta; whereas pancreatic DNA synthesis was reduced. Treatment with AM 251 reduced histological and biochemical signs of pancreatic damage and reversed deleterious effect of anandamide in cerulein-induced acute pancreatitis. CONCLUSIONS: Activation of CB1 receptors evokes opposite effects in the stomach and pancreas: in the stomach, exhibits protective effect against stress-induced gastric mucosal lesions; whereas in the pancreas, increases the severity of cerulein-induced pancreatitis.

Acute Disease↗

PubMed2005

Metallothionein stroma reaction in tumor adjacent healthy tissue in head and neck squamous cell carcinoma and breast adenocarcinoma.

INTRODUCTION: An accumulation of genetic alterations forming the field of cancerization is an important event for the transformation from normal to cancer cell in multistep carcinogenesis. Histopathologically healthy tumor adjacent tissue might be considered as a cancerization field which is typified by genetic changes required for the development of cancer. Metallothionein (MT) is considered to be a protective and anti-apoptotic protein. The aim of our study was to evaluate the MT expression in head and neck squamous cells carcinoma and breast adenocarcinoma and their histologically healthy adjacent tissue. MATERIALS AND METHODS: We have sampled 29 tissue samples in total derived from head and neck cancers and 29 samples of their clear surgical margins, 33 breast adenocarcinomas and 33 clear surgical margins. Antibody recognizing MT-1 was used for immunohistochemical analysis. RESULTS: MT expression was revealed in 85,7% of head and neck cancers and 94% of breast adenocarcinomas. It was found in all tumor adjacent tissue. MT expression was statistically significantly higher in tumor adjacent tissue than in cancer tissue in cases with the presence of lymph node metastases in both, breast adenocarcinoma and head and neck squamous cell carcinoma. Generally stroma seems to respond to the presence of cancer by the expression of MT, even in tissues which normally do not express MT. CONCLUSIONS: MT might be a normal or protective reaction of healthy adjacent tissue to the presence of tumor.

Adenocarcinoma↗

PubMed2004

Melatonin precursor; L-tryptophan protects the pancreas from development of acute pancreatitis through the central site of action.

Melatonin, produced from L-tryptophan, protects the pancreas against acute damage by improving the antioxidative status of tissue. Melatonin receptors have been detected in the brain, but the contribution of these receptors to the pancreatic protection is unknown. The aim of our study was to compare the effects of melatonin precursor; L-tryptophan given intracerebroventricularly (i.c.v.) or intraperitoneally (i.p.) on the course of acute pancreatitis. Acute pancreatitis was induced by subcutaneous infusion of caerulein (5 microg/kg-h x 5 h). L-tryptophan was given i.p. (2.5, 25 or 250 mg/kg) or administered into right cerebral ventricle (0.02, 0.2 or 2.0 mg/rat) 30 min prior to the start of caerulein infusion. Plasma amylase, lipase and TNF alpha activities were measured to determine the severity of caerulein-induced pancreatitis (CIP). The lipid peroxidation products: malonylodialdehyde and 4-hydroksynonenal (MDA + 4-HNE) and activity of superoxide dismutase (SOD) were measured in the pancreas of intact or CIP rats with or without L-tryptophan pretreatment. Melatonin blood level was measured by RIA. CIP was confirmed by histological examination and manifested as an edema and rises of plasma levels of amylase, lipase and TNF alpha (by 550%, 1000% and 600%). MDA + 4-HNE was increased by 600%, whereas SOD activity was reduced by 75% in the pancreas of CIP rats. All manifestations of CIP were significantly reduced by pretreatment of the rats with L-tryptophan given i.c.v. at doses of 0.2 or 2.0 mg/rat, or by peripheral administration of this amino acid used at dose of 250 mg/kg i.p. In control rats plasma level of melatonin averaged about 40 +/- 2 pg/ml and was not significantly affected by CIP, by central application of L-tryptophan (0.02, 0.2 or 2.0 mg/rat) or by peripheral administration of this melatonin precursor used at doses of 2.5 or 25 mg/kg i.p. Plasma melatonin level was markedly increased by pretreatment of the rats with L-tryptophan given i.p. at dose of 250 mg/kg. We conclude that central administration of melatonin precursor; L-tryptophan, as well as peripheral application of high dose of this melatonin precursor prevented the pancreatic damage produced by CIP. The favorable effect of peripherally administered L-tryptophan could be related to the rise of melatonin plasma level and to pancreatoprotective action of this indoleamine. The beneficial effect of centrally administered L-tryptophan could be mediated through activation of central receptors for locally produced melatonin.

Acute Disease↗

PubMed2004

Immunohistochemical expression of FGF-2, PDGF-A, VEGF and TGF beta RII in the pancreas in the course of ischemia/reperfusion-induced acute pancreatitis.

UNLABELLED: Acute pancreatitis leads to pancreatic damage followed by subsequent regeneration. The aim of our study was to evaluate the presence of growth factors in the course of spontaneous pancreatic regeneration after ischemia/reperfusion (I/R)-induced pancreatitis. METHODS: In rats, I/R was evoked by clamping of splenic artery for 30 min followed by reperfusion. Rats were sacrificed 1, 5, 12 h or 1, 2, 3, 5, 7, 9 or 21 days after removal of vascular clips. Pancreatic blood flow (PBF), plasma lipase, interleukin-1beta (IL-1beta), interleukin-10, pancreatic cells proliferation and morphological signs of pancreatitis were determined. Pancreatic presence of fibroblast growth factor-2 (FGF-2), vascular endothelial growth factor (VEGF), platelet-derived growth factor-A (PDGF-A) and transforming growth factor-beta type II receptor (TGFbeta RII) was detected by immunohistochemisty. RESULTS: Exposure to I/R led to the development of acute necrotizing pancreatitis followed by regeneration. Morphological features showed maximal pancreatic damage between the 1(st) and 2(nd) day of reperfusion. It was correlated with a maximal increase in plasma lipase, and pro-inflammatory IL-1beta concentration, as well as, a reduction in PBF and pancreatic DNA synthesis. I/R increased FGF-2 content in pancreatic acinar cells between the 12(th) and 24(th) h, and between 5(th) and 9(th) day of reperfusion. At the 2(nd) day the presence of FGF-2 in pancreatic acinar cells was reduced. After I/R PDGF-A appeared in pancreatic vessels from the 12(th) h to 5 (th) day of reperfusion. PDGF-A was not observed in pancreatic acinar cells in the control or in I/R group. In pancreatic ducts, the presence of PDGF-A was reduced between the 1(st) and 3(rd), and between 7(th) and 9(th) day of reperfusion. In acinar cells, VEGF content was increased after I/R at the time between the 1(st) and 24(th) h, and between 3(rd) and 7(th) day of reperfusion. At the 2(nd) day of reperfusion, VEGF was not detected in the pancreatic acinar cells. Moreover, VEGF was found in the inflammatory infiltration, in the tubular complexes between the 2(nd) and 5(th) day, and in granulation tissue at the 9(th) day of reperfusion. In pancreatic acinar cells, I/R caused an increase in TGFbeta RII presence between the 5(th) and 24(th) h, and between 7(th) and 9(th) day of reperfusion. Between the 2(nd) and 5(th) day of reperfusion the acinar presence of TGFbeta RII was reduced. In the pancreatic ducts, the presence of TGFbeta RII was increased after I/R from the 1(st) h to 9(th) day of observation. Four weeks after induction of acute pancreatitis, the pancreatic regeneration was completed and the presence of growth factors tested returned to control value. CONCLUSIONS: The presence of FGF, VEGF, PDGF-A and TGFbeta RII is modified in the course of I/R-induced acute pancreatitis. Maximal content of FGF, VEGF and TGFbeta RII has been observed in early stage of pancreatic regeneration suggesting the involvement these factors in pancreatic recovery.

Animals↗

PubMed2003

Ghrelin attenuates the development of acute pancreatitis in rat.

BACKGROUND: Ghrelin, a circulating growth hormone-releasing peptide isolated from human and rat stomach, stimulates growth hormone secretion, food intake and exhibits gastroprotective properties. Ghrelin is predominantly produced by a population of endocrine cells in the gastric mucosa, but its presence in bowel, pancreas, pituitary and hypothalamus has been reported. In human fetal pancreas, ghrelin is expressed in a prominent endocrine cell population. In adult pancreatic islets the population of these cell is reduced. The aim of present study was to investigate the influence of ghrelin administration on the development of acute pancreatitis. METHODS: Acute pancreatitis was induced in rat by caerulein injection. Ghrelin was administrated twice (30 min prior to the first caerulein or saline injection and 3 h later) at the doses: 2, 10 or 20 nmol/kg. Immediately after cessation of caerulein or saline injections the following parameters were measured: pancreatic blood flow, plasma lipase activity, plasma interleukin-1beta (IL-1beta) and interleukin 10 (IL-10) concentration, pancreatic DNA synthesis, and morphological signs of pancreatitis. RESULTS: Administration of ghrelin without induction of pancreatitis did not affect significantly any parameter tested. Caerulein led to the development of acute edematous pancreatitis. Treatment with ghrelin at the dose 2 nmol/kg, during induction of pancreatitis, was without effect on pancreatic histology or biochemical and functional parameters. Treatment with ghrelin at the dose 10 and 20 nmol/kg attenuated the development of pancreatitis and the effects of both doses were similar. Administration of ghrelin (10 or 20 nmol/kg) reduced inflammatory infiltration of pancreatic tissue and vacuolization of acinar cells. Also, plasma lipase activity and plasma IL-1beta concentration were reduced, and caerulein-induced fall in pancreatic DNA synthesis was reversed. Administration of ghrelin at the dose 10 and 20 nmol/kg was without effect on caerulein-induced pancreatic edema and pancreatitis-related fall in pancreatic blood flow. CONCLUSIONS: (1) Administration of ghrelin attenuates pancreatic damage in caerulein-induced pancreatitis; (2) Protective effect of ghrelin administration seems Background: Ghrelin, a circulating growth hormone-releasing peptide isolated from human and rat stomach, stimulates growth hormone secretion, food intake and exhibits gastroprotective properties. Ghrelin is predominantly produced by a population of endocrine cells in the gastric mucosa, but its presence in bowel, pancreas, pituitary and hypothalamus has been reported. In human fetal pancreas, ghrelin is expressed in a prominent endocrine cell population. In adult pancreatic islets the population of these cell is reduced. The aim of present study was to investigate the influence of ghrelin administration on the development of acute pancreatitis. Methods: Acute pancreatitis was induced in rat by caerulein injection. Ghrelin was administrated twice (30 min prior to the first caerulein or saline injection and 3 h later) at the doses: 2, 10 or 20 nmol/kg. Immediately after cessation of caerulein or saline injections the following parameters were measured: pancreatic blood flow, plasma lipase activity, plasma interleukin-1beta (IL-1beta) and interleukin 10 (IL-10) concentration, pancreatic DNA synthesis, and morphological signs of pancreatitis. Results: Administration of ghrelin without induction of pancreatitis did not affect significantly any parameter tested. Caerulein led to the development of acute edematous pancreatitis. Treatment with ghrelin at the dose 2 nmol/kg, during induction of pancreatitis, was without effect on pancreatic histology or biochemical and functional parameters. Treatment with ghrelin at the dose 10 and 20 nmol/kg attenuated the development of pancreatitis and the effects of both doses were similar. Administration of ghrelin (10 or 20 nmol/kg) reduced inflammatory infiltration of pancreatic tissue and vacuolization of acinar cells. Also, plasma lipase activity and plasma IL-1beta conc; concentration were reduced, and caerulein-induced fall in pancreatic DNA synthesis was reversed. Administration of ghrelin at the dose 10 and 20 nmol/kg was without effect on caerulein-induced pancreatic edema and pancreatitis-related fall in pancreatic blood flow. Conclusions: (1) Administration of ghrelin attenuates pancreatic damage in caerulein-induced pancreatitis; (2) Protective effect of ghrelin administration seems to be related the inhibition in inflammatory process and the reduction in liberation of pro-inflammatory IL-1beta.

Acute Disease↗

PubMed2003

IGF-1 stimulates production of interleukin-10 and inhibits development of caerulein-induced pancreatitis.

BACKGROUND/AIM: Insulin-like growth factor-1 (IGF-1) and other growth factors overexpression was reported in acute pancreatitis. Previous studies have shown the protective effect of epidermal growth factor (EGF), Hepatocyte Growth Factor (HGF) and Fibroblast Growth Factor (FGF) in the course of experimental acute pancreatitis. The aim of our studies was to determine the effect of IGF-1 administration on the development of caerulein-induced pancreatitis. METHODS: Acute pancreatitis was induced by infusion of caerulein (10 micro/kg/h) for 5 h. IGF-1 was administrated twice at the doses: 2, 10, 50, or 100 micro/kg s.c. RESULTS: Administration of IGF-1 without induction of pancreatitis increased plasma interleukin-10 (IL-10). Infusion of caerulein led to development of acute edematous pancreatitis. Histological examination showed pancreatic edema, leukocyte infiltration and vacuolization of acinar cells. Also, acute pancreatitis led to an increase in plasma lipase and interleukin 1beta (IL-1beta) level, whereas pancreatic DNA synthesis and pancreatic blood flow were decreased. Treatment with IGF-1, during induction of pancreatitis, increased plasma IL-10 and attenuated the pancreatic damage, what was manifested by histological improvement of pancreatic integrity, the partial reversion of the drop in pancreatic DNA synthesis and pancreatic blood flow, and the reduction in pancreatitis-evoked increase in plasma amylase, lipase and IL-1beta level. Protective effect of IGF-1 administration was dose-dependent. Similar strong protective effect was observed after IGF-1 at the dose 2 x 50 and 2 x 100 microg/kg. CONCLUSIONS: (1) Administration of IGF-1 attenuates pancreatic damage in caerulein-induced pancreatitis; (2) This effect is related, at least in part, to the increase in IL-10 production, the reduction in liberation of IL-1beta and the improvement of pancreatic blood flow.

Animals↗

PubMed2002

The influence of epidermal growth factor on the course of ischemia-reperfusion induced pancreatitis in rats.

UNLABELLED: Acute pancreatitis is accompanied by the enhanced expression of EGF in the pancreas and the administration of EGF was found to exhibit the beneficial effect on edematous cerulein-induced pancreatitis. Therefore, we decided to determine the influence of EGF on necro-hemorrhagic pancreatitis induced by ischemia and reperfusion (I/R). Acute pancreatitis was induced in rats by restricting the pancreatic blood flow (PBF) in the inferior splenic artery for 30 min using microvascular clips. EGF was administered three times daily (10 microg/kg per dose s.c.) starting immediately after the clips removal. Rats were sacrificed on day 1, 3, 5, 10 and 21 following ischemia. PBF was measured using a laser Doppler flowmeter. Morphological signs of pancreatitis, as well as the levels of plasma amylase, lipase, interleukin-1beta and interleukin-10 concentration and pancreatic cell proliferation were examined. RESULTS: Ischemia with reperfusion caused acute necro-hemorrhagic pancreatitis with a histological and biochemical manifestation of pancreatic damage, followed by a spontaneous regeneration. The administration of EGF caused the reduction in the histological signs of pancreatic damage, such as necrosis, edema and leukocyte infiltration, and accelerated the pancreatic repair. Also, EGF treatment significantly attenuated the reduction in pancreatic blood flow and DNA synthesis. The activity of plasma amylase and lipase, as well as plasma interleukin-1beta and interleukin-10 concentrations were decreased in EGF treated animals. CONCLUSIONS: EGF exerts beneficial influence on the course of I/R induced pancreatitis and this effect seems to be related to the reduction in the activation of pro-inflammatory interleukin cascade, the improvement of PBF, and the increase in pancreatic cell growth.

Amylases↗

PubMed2002

Role of endogenous melatonin and its MT2 receptor in the modulation of caerulein-induced pancreatitis in the rat.

The present study investigated the involvement of endogenous melatonin in the prevention of pancreatic damage provoked by caerulein-induced pancreatitis (CIP) by using the luzindole, the antagonist of melatonin MT2 receptors. CIP was produced by subcutaneous infusion of caerulein to conscious rats (25 microg/kg). Luzindole (1, 2 or 4 mg/kg) was given as an intraperitoneal bolus injection 30 min prior to the start of CIP. Lipid peroxidation products, malondialdehyde (MDA) and 4-hydroxynonenal (4-HNE) were measured in the pancreas by LPO-584 commercial kit. CIP was confirmed by histological examination and manifested by significant increases of plasma activities of amylase, lipase and tumor necrosis factor alpha (TNFalpha) (by 500%, 1000% and 600%, respectively) comparing to the control values. This was accompanied by a 40% limitation in pancreatic blood flow (PBF) and by 200% increase of MDA+4-HNE in the pancreas of CIP rats. Administration of luzindole to the CIP rats reduced PBF, aggravated the histological manifestations of pancreatitis, resulted in the significant augmentation of pancreatic MDA + 4-HNE content, and produced the marked increases of plasma levels of lipase, amylase and TNFalpha, comparing to the values observes in the rats with CIP alone. These results suggest that endogenous melatonin through its receptor MT2 plays an important role in the attenuation of pancreatic damage produced by overstimulation with caerulein.

Amylases↗

PubMed2001

Hepatocyte growth factor attenuates pancreatic damage in caerulein-induced pancreatitis in rats.

Hepatocyte growth factor (HGF) overexpression was reported in experimental and clinical acute pancreatitis. These observations prompted us to determine the effect of HGF administration on the development of caerulein-induced pancreatitis in rats. Acute pancreatitis was induced by s.c. infusion of caerulein (10 microg/kg/h) for 5 h. HGF was administrated twice (30 min before caerulein or saline infusion and 3 h later) at the doses: 0.4, 2, 10 or 50 microg/kg s.c. Immediately after cessation of caerulein or saline infusion, the pancreatic blood flow, plasma amylase and lipase activity, plasma cytokines concentration, cell proliferation, and morphological signs of pancreatitis were examined. Caerulein administration induced acute edematous pancreatitis manifested by 41% decrease in DNA synthesis, 53% inhibition of pancreatic blood flow, a significant increase in plasma amylase and lipase activity, plasma interleukin-1beta and interleukin-6 concentration, as well as, the development of the histological signs of pancreatic damage (edema, leukocyte infiltration, and vacuolization). Administration of HGF without induction of pancreatitis increased plasma interleukin-10. Treatment with HGF, during induction of pancreatitis, increased plasma interleukin-10 and attenuated the pancreatic damage, what was manifested by histological improvement of pancreatic integrity, the partial reversion of the drop in DNA synthesis and pancreatic blood flow, and the reduction in pancreatitis evoked increase in plasma amylase, lipase, and interleukin-1beta and interleukin-6 levels. HGF administrated at the dose 2 microg/kg exhibited a similar beneficial effect as administration of HGF at the doses 10 or 50 microg/kg. Treatment with HGF at the dose 0.4 microg/kg was less effective. We conclude that: (1) administration of HGF attenuates pancreatic damage in caerulein-induced pancreatitis; (2) this effect seems to be related to the increase in production of interleukin-10, the reduction in release of interleukin-1beta and interleukin-6, and the improvement of pancreatic blood flow.

Amylases↗

PubMed2001

Application of neural networks to the classification of pancreatic intraductal proliferative lesions.

The aim of the study was to test applycability of neural networks to classification of pancreatic intraductal proliferative lesions basing on nuclear features, especially chromatin texture. Material for the study was obtained from patients operated on for pancreatic cancer, chronic pancreatitis and other tumours requiring pancreatic resection. Intraductal lesions were classified as low and high grade as previously described. The image analysis system consisted of a microscope, CCD camera combined with a PC and AnalySIS v. 2.11 software. The following texture characteristics were measured: variance of grey levels, features extracted from the grey levels correlation matrix and mean values, variance and standard deviation of the energy obtained from Laws matrices. Furthermore we used moments derived invariants and basic geometric data such as surface area, the minimum and maximum diameter and shape factor. The sets of data were randomly divided into training and testing groups. The training of the network using the back-propagation algorithm, and the final classification of data was carried out with a neural network simulator SNNS v. 4.1. We studied the efficacy of networks containing from one to three hidden layers. Using the best network, containing three hidden layers, the rate of correct classification of nuclei was 73%, and the rate of misdiagnosis was 3%; in 24% the network response was ambiguous. The present findings may serve as a starting point in search for methods facilitating early diagnosis of ductal pancreatic carcinoma.

Adenocarcinoma↗

PubMed2001

Involvement of cyclooxygenase-derived prostaglandin E2 and nitric oxide in the protection of rat pancreas afforded by low dose of lipopolysaccharide.

Prostaglandins (PG), the products of arachidonate metabolism through cyclooxygenase (COX) pathway, protect the pancreas from the acute damage. The existence of two isoforms of COX was documented including: COX-1, present in normal tissues and COX-2, expressed at the site of inflammation, such as induced by bacterial lipopolysaccharide (LPS). Pretreatment with low dose of LPS and activation of nitric oxide (NO) synthase (NOS) has been shown to prevent the injury caused by caerulein-induced pancreatitis (CIP) in the rat. The aim of this study was to investigate the role of COX-1 and COX-2 in the LPS-induced protection of the pancreas against CIP and the involvement of NOS in the activation of COX-PG system in the rats with CIP. CIP was produced by subcutaneous (s.c.) infusion of caerulein (5 microg/kg-h for 5 h) to the conscious rats. Protective dose of LPS, from Escherichia coli, (1 mg/kg) was given intraperitoneally (i.p.) 15 min prior to the start of CIP. Nonselective inhibitor of COX; indomethacin (5 or 10 mg/kg), selective inhibitor of COX-1: resveratrol, or a highly selective inhibitors of COX-2: rofecoxib or NS-398 (2 or 10 mg/kg) were injected i.p. 15 min prior to the administration of LPS. COX-1 or COX-2 mRNA was determined by reverse transcription-polimerase chain reaction (RT-PCR) in the pancreatic tissue. Pancreatic blood flow (PBF) was measured by a laser Doppler flowmetry. PGE2 content in the pancreas was measured by radioimmunoassay. CIP was manifested by an increase of pancreatic weight and plasma amylase activity (by 500% and 700%, respectively) and it was confirmed by histological examination. CIP slightly increased pancreatic PGE2 generation (by 12%) and diminished PBF (by about 40%). LPS (1 mg/kg i.p.), given prior to the start of CIP, increased PGE2 generation in the pancreas (by 45%), reversed the histological manifestations of pancreatitis, reduced the rise in amylase blood level and improved PBF. Administration of nonselective inhibitor of COX; indomethacin (5 or 10 mg/kg i.p.) prior to the injection of LPS abolished its protective effects on CIP and reduced pancreatic PGE2 generation. Selective inhibitor of COX-1; resveratrol (10 mg/kg i.p.) given prior to the injection of LPS reversed its protective effects against CIP. Pretreatment with a selective inhibitors of COX-2: rofecoxib or NS-398 (10 mg/kg) attenuated LPS-induced pancreatic protection in the CIP rats. COX-1 expression was detected in the intact pancreas and was not significantly changed by CIP, LPS, indomethacin, NS-389 and their combination, while COX-2 mRNA expression appeared in the pancreas of ratssubjected to CIP and was significantly increased after LPS injection to these rats. Addition of selective COX-2 inhibitor; NS-389, or nonselective inhibitor of COX; indomethacin, enhanced COX-2 mRNA expression in the rats with CIP pretreated with LPS. Pretreatment of the rats with inhibitor of NOS; L-NNA (20 mg/kg i.p.), given together with LPS, 15 min prior to the start of caerulein overstimulation, resulted in complete reversion of LPS-induced pancreatic protection and decreased PGE2 generation stimulated by LPS. Addition to L-NNA of the substrate for NOS; L-arginine (100 mg/kg i.p.), restored pancreatic protection afforded by low dose of LPS and increased pancreatic PGE2 level in the rats with CIP. We conclude that: 1. increased pancreatic PGE2 generation, induced by low dose LPS pretreatment, contributes to the pancreatic resistance to acute damage produced by caerulein overstimulation and 2. the NO-system is involved in above stimulation of PGE2 generation and pancreatic protection against acute damage.

Acute Disease↗

PubMed2001

Pancreatic damage and regeneration in the course of ischemia-reperfusion induced pancreatitis in rats.

The objective of this study was to assess the biochemical and histological signs of pancreatic damage development and pancreatic recovery in the course of ischemia-reperfusion induced pancreatitis. Acute pancreatitis was induced in rats by limitation of pancreatic blood flow (PBF) in inferior splenic artery for 30 min using microvascular clips, followed by reperfusion. Rats were sacrificed at the time: 1 h, 12 h, 24 h, and 2, 3, 5, 7, 10, 14, 21 and 28 days after ischemia. PBF was measured using laser Doppler flowmeter. Plasma amylase, interleukin 1beta (IL-1beta) and interleukin 10 (IL-10) concentration, pancreatic DNA synthesis, as well as, morphological features of pancreatic damage were examined. Ischemia with reperfusion caused acute necrotizing pancreatitis followed by pancreatic regeneration. After removal of microvascular clips, PBF was reduced and the maximal fall of PBF was observed 24 h after ischemia, then PBF grew reaching the control value at 28th day. Plasma amylase activity was increased between 12th h and 3rd day with maximum at 24 h after ischemia. Also plasma IL-1beta and IL-10 were elevated with maximal value at the first and second day after ischemia, respectively. DNA synthesis was maximally reduced at the first day (by 70%) and from second day the reversion of this tendency was observed with full restoration of pancreatic DNA synthesis within four weeks. Morphological features of pancreatic tissue showed necrosis, strongly pronounced edema and leukocyte infiltration. Maximal intensity of morphological signs of pancreatic damage was observed between first and second day of reperfusion. During pancreatic regeneration between second and tenth day after ischemia the temporary appearance of chronic pancreatitis-like features such as fibrosis, acinar cell loss, formation of tubular complexes and dilatation of ducts was observed. The regeneration was completed within four weeks after pancreatitis development. We conclude that partial and temporary pancreatic ischemia followed by reperfusion causes acute necrotizing pancreatitis with subsequent regeneration within four weeks. Pancreatic repair after necrotizing pancreatitis is connected with the increase in plasma IL-10 concentration and transitory formation of tubular complexes.

Animals↗

PubMed2001

Effect of sensory nerves and CGRP on the development of caerulein-induced pancreatitis and pancreatic recovery.

The function of primary sensory neurons is to receive and transmit information from external environment and these neurons are able to release neuromediators from the activated peripheral endings. The aim of this study was to determine the influence of sensory nerves and administration of their mediator--calcitonin gene related peptide (CGRP) on the course of acute pancreatitis (AP). Ablation of sensory nerves was performed by neurotoxic dose of capsaicin (100 mg/kg). Single or repeated episodes of AP were induced by caerulein infusion (10 microg/kg/h for 5 h). Five repeated AP were performed once a week. Capsaicin at the dose which stimulates sensory nerves (0.5 mg/kg/dose) or CGRP (10 microg/kg/dose) was administrated before and during or after single induction of AP, as well as, after each induction of repeated AP. Rats were killed at the time 0, 3 or 9 h after single induction of AP or two weeks after last induction of repeated AP. Ablation of sensory nerves aggravated pancreatic damage in caerulein-induced AP. Treatment with stimulatory doses of capsaicin or CGRP before and during single induction of AP attenuated the pancreatic damage in morphological examination. This effect was also manifested by partial reversion of AP evoked drop in DNA synthesis and pancreatic blood flow (PBF). Administration of CGRP after single AP induction aggravated histologically manifested pancreatic damage. The further decrease in PBF and DNA synthesis was also observed. Animals with five episodes of AP showed almost full pancreatic recovery two weeks after last induction of AP concerning all parameters tested. In stimulatory doses of capsaicin treated rats, we observed the decrease in pancreatic amylase and fecal chymotrypsin activity, as well as, the drop in DNA synthesis. Similar but less pronounced effects were observed after treatment with CGRP. We conclude that effect of sensory nerves and CGRP on AP is two-phase and time dependent. Stimulation of sensory nerves or the administration of CGRP during development of AP exhibits protective effects against pancreatic damage induced by caerulein overstimulation. After induction of AP, persistent activity of sensory nerves and presence of CGRP aggravate pancreatic damage and lead to functional insufficiency typical for chronic pancreatitis.

Acute Disease↗

PubMed2001

[Lateral cervical cyst in 13-year-old girl].

We present a clinical description of a 13-year-old girl with lateral cervical cyst. We particularly emphasize the need for ultrasonographic examination during routine diagnostics of so-called cervical tumors.

Adolescent↗

PubMed2000

Epidermal growth factor accelerates pancreatic recovery after caerulein-induced pancreatitis.

We examined the influence of endogenous and exogenous epidermal growth factor (EGF) on pancreatic repair after acute pancreatitis. Caerulein-induced pancreatitis was evoked in rats with intact or removed salivary glands and EGF (10 microg/kg) was administered starting 24 h after cessation of caerulein infusion. The dose of EGF 10 microg/kg was chosen because it was the most effective in preliminary experiments when 1, 10 or 50 microg/kg of EGF was used. Caerulein administration caused acute edematous pancreatitis with biochemical and histological manifestation of pancreatic damage, followed by spontaneous regeneration. The effect of salivectomy on the course of acute pancreatitis was slight, resulting in additional reduction in pancreatic blood flow, DNA synthesis and in an increase in plasma interleukin 1beta level. Treatment with EGF accelerated the healing of pancreatic damage, causing an increase in pancreatic blood flow and DNA synthesis. EGF caused faster normalization of plasma amylase and lipase activity and plasma interleukin 1beta concentration, as well as, this peptide accelerated the restoration of pancreatic amylase activity. On histological examination, EGF caused reduction of pancreatic damage and acceleration of tissue repair. We conclude that EGF reduces the severity of pancreatic damage evoked by caerulein-induced pancreatitis-related pancreatic damage and accelerates tissue repair. The beneficial effects of EGF appear to depend, at least in part, on the improvement of pancreatic blood flow, as well as on an increase of pancreatic cell growth and limitation of the activation cytokine release.

Amylases↗

PubMed2000

Protective action of lipopolysaccharidesin rat caerulein-induced pancreatitis: role of nitric oxide.

Lipopolysaccharides (LPS), the component of the cell wall of gram-negative bacteria, have been implicated in the pathogenesis of acute pancreatitis, but the mechanism of their action on the pancreas has not been fully explored. The aim of this study was to investigate the effects of various doses of LPS on the integrity of intact pancreas and that involved in acute caerulein-induced pancreatitis (CIP) in the rat and to compare these effects with those of nitric oxide (NO) donor, S-nitrose-acetylpenicillamine (SNAP). The expression of constitutive NO synthase (cNOS) and inducible NO synthase (iNOS) mRNA was also examined in the isolated pancreatic acini obtained from the inflamed pancreas of rats treated with LPS. CIP was produced by subcutaneous (s.c.) infusion of caerulein (5 microg/kg.h for 5 h) to conscious rats. Bolus injections of various doses of LPS (0.1, 1, 10, 20 or 40 mg/kg) or SNAP (1.5, 3 or 6 mg/kg) were made intraperitoneally (i.p.) either alone or 30 min prior to s.c. infusion of caerulein to induce CIP. Infusion of caerulein produced acute pancreatitis confirmed by histological examination and manifested by an increase of pancreatic mass (by about 200%). Blood levels of amylase and lipase were augmented by 400 and 800% respectively, whereas the pancreatic blood flow (PBF) was decreased by 50% in rats with CIP. Injection of low doses of LPS (0.1-1 mg/kg i.p.) or SNAP (1.5-3 mg/kg i.p.) 30 min prior to caerulein infusion reversed the harmful effects of pancreatic overstimulation with caerulein and reduced significantly the histological manifestations of CIP such as edema, neutrophil infiltration and vacuolization of the acinar cells. These protective effects of low doses of LPS pretreatment on the pancreas were completely antagonized by the suppression of the activity of NO synthase (NOS) with N(G)-nitro-L-arginine (L-NNA) applied (20 mg/kg i.p.) 15 min prior to the LPS injection. Combination of L-arginine (100 mg/kg i.p.), a substrate for NOS, with L-NNA given prior to low doses of LPS, restored the LPS-induced protection of the pancreas in rats with CIP. In contrast, higher doses of LPS (20-40 mg/kg i.p.) or SNAP (6 mg/kg i.p.), which produced a significant fall of the PBF, did not protect the pancreas against CIP. Administration of various doses of LPS to rats with CIP resulted in significant and dose-dependent stimulation of NO biosynthesis in the isolated acini obtained from the pancreas of these animals. LPS enhanced the expression of both cNOS and iNOS in the pancreatic acini obtained from rats subjected to CIP. The signal for cNOS mRNA was detected in all samples, reaching peak at the protective dose of LPS (1 mg/kg i. p.), while iNOS was overexpressed only at the highest doses of LPS that failed to exhibit the protective activity. We conclude that the pretreatment with low doses of LPS protects the pancreas against the damage provoked by CIP and this effect could be attributed, at least in part, to the activation of L-arginine-NO system in the pancreas.

Animals↗

PubMed2000

Protective role of endogenous nitric oxide (NO) in lipopolysaccharide--induced pancreatic damage (a new experimental model of acute pancreatitis).

Lipopolysaccharide (LPS) derived from the bacterial cell wall activates the inflammatory response in the tissue but the role of LPS in the pathogenesis of pancreatic damage and in the activation of NO system in the pancreas has not been fully explained. The aim of this study was to investigate the effect of repeated administration of LPS to the rats on the integrity of the pancreas, on the ability of isolated pancreatic acini to secrete the amylase and on the plasma level of tumor necrosis factor alpha (TNFalpha). The role of NO in the pancreatic resistance to the damage was assessed in animals subjected to repeated administration of LPS. To induce pancreatic damage one group of rats received intraperitoneal (i.p.) injection of LPS (from E. coli) every day during 5 consecutive days (10 mg/kg--day). Another groups of animals were given N(G)-nitro-L-arginine (L-NNA), an inhibitor of NO synthase (NOS) (20 mg/kg i.p.) alone or in combination with L-arginine (100 mg/kg i.p.), 30 min prior to each LPS injection. Plasma level of TNFalpha was determined by ELISA kit. Repeated administration of LPS produced mild pancreatic inflammation that was most pronounced at day 5 of LPS treatment and manifested as edema, neutrophil infiltration and hemorrhage of the pancreas. The survival rate after 5 days treatment with LPS was 87.5%. Pancreatic weight, plasma levels of TNFalpha and amylase, pancreatic blood flow (PBF) and NO generation by pancreatic acini were markedly increased in rats subjected to repeated administration of LPS whereas the amylase response of isolated pancreatic acini to pancreatic secretagogues was significantly attenuated. Suppression of NOS by L-NNA resulted in a dramatic increase in the mortality of the animals reaching 50% and significantly increased inflammatory changes in the pancreatic tissue, decreased PBF, abolished the ability of pancreatic acini to release NO and to secrete amylase. Pancreatic weight and plasma levels of amylase and TNFalpha significantly increased in the group of rats treated with combination of LPS+L-NNA as compared to the animals received LPS alone. Addition of L-arginine to L-NNA+LPS administration reversed all harmful effects produced by L-NNA in the pancreas. We conclude that repeated administration of high doses of bacterial LPS to the rats could induce pancreatic tissue damage by itself, however, it is not able to produce severe pancreatitis. Suppression of NO generation significantly aggravates the pancreatic lesion produced by LPS leading to the dramatic mortality in treated rats. The rise of plasma level of TNFalpha corresponds to the severity of pancreatic inflammation.

Acute Disease↗