Bonior J

Protective effect of melatonin and its precursor L-tryptophan on acute pancreatitis induced by caerulein overstimulation or ischemia/reperfusion

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

Involvement of sensory nerves in the protective effect of growth hormone on acute pancreatitis

UNLABELLED Growth hormone (GH) has been shown to protect the intestinal barrier integrity and to stimulate the production of insulin-like growth factor 1 (IGF-1), which inhibits the development of acute pancreatitis. Sensory nerves are implicated in the protection of pancreatic tissue against acute inflammation. The aim of this study was to investigate the influence of exogenous GH on acute pancreatitis (AP) and to assess the involvement of sensory nerves and IGF-1 in above effect. Studies were performed on Wistar rats. AP was induced by subcutaneous administration of caerulein (25mug/kg) to the conscious animals. GH (1 or 2mg/kg) was administered to the rats as an intraperitoneal injection 30min prior to the start of AP. To deactivate sensory nerves capsaicin was given at total dose of 100mg/kg 10days before the experiments. AP was confirmed by histological examination and manifested by the significant rises of pancreatic weight, and serum activities of lipase, TNFalpha and IL-10 (by 550%, 300% and 50%, respectively), whereas IGF-1 blood concentration was markedly reduced. Administration of GH prior to the caerulein infusion significantly increased GH, IGF-1 and IL-10 blood levels, attenuated harmful effects of AP and reduced histological manifestations of pancreatitis in the rats with intact sensory nerves. This was accompanied by the reduction of serum lipase, and TNFalpha activities. In the AP rats with capsaicin-deactivated sensory nerves GH failed to protect the pancreas against acute damage and, as a consequence of above deactivation, IGF-1 was low. CONCLUSION GH modulates the development of acute pancreatitis in the presence of active sensory nerves probably via stimulation of IGF-1 release.

Exogenous Ghrelin Accelerates the Healing of Acetic Acid-Induced Colitis in Rats

Previous studies have shown that ghrelin reduces colonic inflammation induced by trinitrobenzene sulfonic acid and dextran sodium sulfate. In the present study we determined the effect of treatment with ghrelin on the course of acetic acid-induced colitis in rats. Rectal administration of 3% acetic acid solution led to induction of colitis in all animals. Damage of the colonic wall was accompanied by an increase in mucosal concentration of pro-inflammatory interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α), as well mucosal activity of myeloperoxidase. Moreover, induction of colitis led to a reduction in colonic blood flow and DNA synthesis. Administration of ghrelin after induction of colitis led to faster regeneration of the colonic wall and reduction in colonic levels of IL-1β, TNF-α, and myeloperoxidase. In addition, treatment with ghrelin improved mucosal DNA synthesis and blood flow. Our study disclosed that ghrelin exhibits a strong anti-inflammatory and healing effect in acetic acid-induced colitis. Our current observation in association with previous findings that ghrelin exhibits curative effect in trinitrobenzene sulfonic acid- and dextran sodium sulfate-induced colitis suggest that therapeutic effect of ghrelin in the colon is universal and independent of the primary cause of colitis.

Long-Lasting Effect of Infant Rats Endotoxemia on Heat Shock Protein 60 in the Pancreatic Acinar Cells: Involvement of Toll-Like Receptor 4

Introduction. Lipopolysaccharide endotoxin (LPS) is responsible for septic shock and multiorgan failure, but pretreatment of rats with low doses of LPS reduced pancreatic acute damage. Aim. We investigated the effects of the endotoxemia induced in the early period of life on Toll-like receptor 4 (TLR4), heat shock protein 60 (HSP60) and proapoptotic Bax, caspase-9 and -3 or antiapoptotic Bcl-2 protein expression in the pancreatic acinar cells of adult animals. Material and Methods. Newborn rats (25 g) were injected with endotoxin (Escherichia coli) for 5 consecutive days. Two months later, pancreatic acinar cells were isolated from all groups of animals and subjected to caerulein stimulation (10−8 M). Protein expression was assessed employing Western blot. For detection of apoptosis we have employed DNA fragmentation ladder assay. Results. Preconditioning of newborn rats with LPS increased TLR4, Caspase-9 and -3 levels, but failed to affect basal expression of HSP60, Bax, and Bcl-2. Subsequent caerulein stimulation increased TLR4, Bcl-2, and caspases, but diminished HSP60 and Bax proteins in pancreatic acinar cells. Endotoxemia dose-dependently increased TLR4, Bax, HSP60, and both caspases protein signals in the pancreatic acini, further inhibiting antiapoptotic Bcl-2. Conclusions. Endotoxemia promoted the induction of HSP60 via TLR4 in the infant rats and participated in the LPS-dependent pancreatic tissue protection against acute damage.

Bilateral vagotomy attenuates the severity of secretagogue-induced acute pancreatitis in the rat.

PURPOSE We assessed the effect of bilateral vagotomy (BV) on the course of acute caerulein-induced pancreatitis (AP) in the rat. MATERIAL/METHODS The study was performed on Wistar rats surgically prepared by subdiaphragmatic BV. Control group underwent sham operation. Four days later, AP was induced by subcutaneous injection of caerulein (25 μg/kg/5h) to the conscious animals with or without BV. After administration of caerulein the blood samples were taken for determination of serum lipase activity and interleukin-10 (IL-10) concentration. Pancreatic tissue samples were subjected to histological examinations and to the measurement of lipid peroxidation products (MDA+4-HNE) concentration and the activity of an antioxidant enzyme - glutathione peroxidase (GPx). After application of caerulein pancreatic blood flow was measured by laser Doppler flowmetry. RESULTS AP was manifested by oedema and neutrophil infiltration of the pancreatic tissue and accompanied by significant increases of serum lipase activity, serum concentration of IL-10 and pancreatic concentration of MDA+4HNE (ca. 50×, 2× and 4× respectively p ≥ 0.05). Pancreatic activity of GPx and pancreatic blood flow were decreased (both by 60%). In vagotomised rats with AP serum lipase activity and pancreatic concentration of MDA+4-HNE were lower whereas Il-10 concentration and pancreatic activity of GPx, as well as pancreatic blood flow were significantly higher as compared to AP rats with intact vagal nerves. In AP rats with vagotomy all histological signs of pancreatitis were significantly reduced. CONCLUSIONS Bilateral vagotomy resulted in the significant attenuation of caerulein-induced pancreatitis in the rat.

MELATONIN AND ITS METABOLITE N1-ACETYL-N2-FORMYL-5-METHOXYKYNURAMINE (AFMK) ENHANCE CHEMOSENSITIVITY TO GEMCITABINE IN PANCREATIC CARCINOMA CELLS (PANC-1)

BACKGROUND Gemcitabine is a standard chemotherapeutic agent for patients suffering from pancreatic cancer. However, the applied therapy is not effective due to the resistance of tumor cells to cytostatics, caused by inefficiency of the apoptotic mechanisms. Herein, we present the hypothesis that melatonin and its metabolite N1-acetyl-N2-formyl-5-methoxykynuramine (AFMK) modify the effect of gemcitabine on PANC-1 cells and that this phenomenon is dependent on the modulation of apoptosis. METHODS PANC-1 cells have been incubated with melatonin, AFMK or gemcitabine alone or in combination to determine the cytotoxity and proliferative effects. In subsequent part of the study, cells were harvested, the proteins were isolated and analyzed employing immunoprecipitation/immunoblotting. RESULTS Incubation of PANC-1 cells with gemcitabine resulted in upregulation of pro-apoptotic bax and caspases proteins expression, downregulation of anti-apoptotic Bcl-2, heat shock proteins (HSPs) and modulation of cellular inhibitors of apoptosis (IAPs). Both melatonin and AFMK administered to PANC-1 in combination with gemcitabine inhibited the production of HSP70 and cIAP-2 as compared to the results obtained with gemcitabine alone. These changes were accompanied by upregulation of Bax/Bcl-2 ratio and reduction of procaspases-9 and -3 abundance, followed by an increase in the formation of active caspase of PANC-1 cells with combination of gemcitabine plus low doses of melatonin or AFMK led to enhanced cytotoxicity and resulted in the inhibition of PANC-1 cells growth as compared to effects of gemcitabine alone. CONCLUSION Melatonin and AFMK could improve the anti-tumor effect of gemcitabine in PANC-1 cells presumably through the modulation of apoptotic pathway.

Czynniki wpływające na strategie radzenia sobie z bólem przewlekłym u chorych z niedokrwieniem kończyn dolnych

Wstep. Osoby z chorobą niedokrwienną konczyn dolnych stanowią okolo 3–10% populacji światowej. Schorzenia przewlekle, ktorym towarzyszy wystepowanie bolu, prowadzą do wyczerpania rezerw mechanizmow obronnych czlowieka. Wystepująca choroba przewlekla wymaga od chorego elastyczności oraz adaptacji. Cel pracy. Analiza wplywu jakości zycia oraz charakteru dolegliwości bolowych na podejmowane strategie radzenia sobie z bolem przewleklym u chorych z niedokrwieniem konczyn dolnych. Material i metody. Badanie przeprowadzono wśrod chorych hospitalizowanych na Oddziale Chirurgii Naczyniowej oraz w Poradni Chirurgii Naczyn Szpitala Uniwersyteckiego w Krakowie w 2015 r. Objeto nim grupe 105 chorych, ktorzy odczuwali bol przewlekly. W badaniu zastosowano metode sondazu diagnostycznego, technike ankietowania, w ktorej wykorzystano narzedzia: kwestionariusz ankiety wlasnej konstrukcji, kwestionariusz WHOQOL-BREF, skale bolu VAS oraz Kwestionariusz Strategii Radzenia Sobie z Bolem (CSQ), skale Fontaine’a. Wyniki. Badania wskazaly na wystepowanie zalezności pomiedzy natezeniem bolu, czasem trwania dolegliwości, jakością zycia i okolicznościami wystepowania bolu, a obieranymi przez badanych strategiami radzenia sobie z bolem. Wnioski. Bol przewlekly jest zjawiskiem dynamicznym. Na podejmowane przez chorych strategie w radzeniu sobie z bolem wplyw mają czynniki związane z klinicznym charakterem odczuwanego bolu. Zachodzi koniecznośc opracowania wytycznych do pracy z chorymi cierpiącymi na bol w przebiegu choroby niedokrwiennej konczyn dolnych.