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The gut mucosal barrier plays a key role in the physiology of gastrointestinal (GI) tract, preventing under homeostatic conditions, the epithelial cells of the gastric mucosa from hydrochloric acid and intestinal mucosa from alkaline secretion, food toxins and pathogenic microbiota. Previous studies have documented that blockade of both isoforms of cyclooxygenase (COX): constitutive (COX-1) and inducible (COX-2), as well NO synthase in the stomach exacerbated the gastric damage induced by various ulcerogens, however, such as effects of non-selective and selective inhibition of COX-1, COX-2 and NOS enzymes on colonic damage have been little studied. The supplementation of NO by intragastric (i.g.) treatment with NO-releasing compound NO-aspirin (NO-ASA) or substrate for NO synthase L-arginine ameliorated the damage of upper GI-tract, but whether similar effect can be observed in colonic mucosa associated with the experimental colitis, and if above mentioned compounds can be effective in aggravation or protection of experimental colitis remains less recognized. In this study rats with experimental colitis induced by intrarectal administration of 2,4,6-trinitrobenzosulphonic acid (TNBS) were daily treated for 7 days with: 1) vehicle (i.g.), 2) ASA 40 mg/kg (i.g.), 3) rofecoxib 10 mg/kg (i.g.), 4) resveratrol 10 mg/kg (i.g.), 5) NO-ASA 40 mg/kg (i.g.), 6) L-arginine 200 mg/kg (i.g.) with or without of L-NNA 20 mg/kg (i.p.). The macroscopic and microscopic area of colonic damage was determined planimetrically, the colonic blood flow (CBF) was assessed by Laser flowmetry, and the oxidative stress biomarkers malondialdehyde and 4-hydroxynonenal (MDA+4-HNE), the antioxidative factors superoxide dismutase (SOD) and glutathione (GSH), as well as proinflammatory cytokines in the colonic mucosa (tumor necrosis factor alpha (TNF-a) and interleukin-1beta (IL-1β)) were measured. We have documented that administration of TNBS produced gross and microscopic colonic damage and significantly decreased CBF (p<0.05). Treatment with ASA significantly increased the area of colonic damage (p<0.05), an effect accompanied by a significant decrease in the CBF, the significant increment of MDA+4- HNE, and the attenuation of the antioxidative properties in colonic mucosa, documented by a significant decrease of SOD activity and GSH concentration, and elevation of the colonic tissue levels of TNF-α and IL-1β comparing to control Veh-treated TNBS rats. Administration of rofecoxib or resveratrol also significantly increased the colonic damage and significantly decreased the CBF, causing an increase in MDA+4-HNE and mucosal content of TNF-α and IL-1α and a significant decrease of the SOD activity and GSH content (p<0.05), however, these changes were significantly less pronounced as compared with ASA. On the contrary, the treatment with NO-ASA, or L-arginine, significantly diminished the area of colonic lesions, the MDA+4-HNE concentration, attenuated the TNF-α and IL- 1β levels, while increasing the CBF, SOD activity and GSH content (p<0.05). The concomitant treatment of L-NNA with rofecoxib or resveratrol reversed an increase in area of colonic damage and accompanying changes in CBF, colonic mucosa TNF-α and IL-1β levels, the MDA+4-HNE concentration, and SOD activity and GSH content comparing to those observed in TNBS rats treated with these COX-inhibitors alone (p<0.05). In contrast, cotreatment with L-NNA and NO-ASA or L-arginine failed to significantly affect the decrease of colonic lesions accompanied by the rise in CBF, the attenuation of MDA+4-HNE concentration, TNF-α and IL-1β levels, SOD activity and GSH content exerted by NO-ASA- or L-arginine treatment of the respective control TNBS-rats without L-NNA administration. These observations suggest that 1) the increase of NO availability either from NO-releasing donors such as NO-ASA or NO precursors such as L-arginine, can inhibit the inflammatory and microvasculature alterations, as well as increase in lipid peroxidation due to the enhanced efficacy of these compounds to increase the antioxidative properties of colonic mucosa, 2) unlike ASA which exacerbated the severity of colitis, the treatment with rofecoxib, the specific 'safer' COX-2 inhibitor or resveratrol, the polyphenolic compound known to act as the dual COX-1 and COX-2 inhibitor, can attenuate the colonic damage during course of TNBS colitis possibly via antiinflammatory and antioxidative properties, and 3) the blockade of endogenous NO activity by L-NNA which also exacerbated the severity of mucosal damage in colitis, can abolish the sparing effect of rofecoxib and resveratrol indicating the NO bioavailability plays an important role in enhanced efficacy of both specific and dual COX inhibitors to ameliorate the experimental colitis. [ABSTRACT FROM AUTHOR]

Acute pancreatitis (AP) is the most common gastrointestinal disease leading to hospitalizations and unexpected deaths. The development of AP leads to damage of the pancreatic microcirculation with a cascade of subsequent events resulting, among others, in coagulopathy. Previous research showed that anticoagulants can be important therapeutic agents. Heparin and acenocoumarol can alleviate the course of AP, as well as accelerate healing and post-inflammatory regeneration of the pancreas. The aim of this study was to determine whether warfarin, a drug with more stable effects than acenocoumarol, affects the healing and regeneration of the pancreas in the cerulein-induced AP. AP was evoked in Wistar male rats by intraperitoneal administration of cerulein. The first dose of warfarin (45, 90 or 180 µg/kg) was administered 24 hours after the first dose of cerulein and the doses of warfarin were repeated once a day in subsequent 10 days. The severity of AP was assessed immediately after the last dose of cerulein, as well as at days 1, 2, 3, 5, and 10 after AP induction. Treatment with warfarin dose-dependently increased international normalized ratio (INR) and attenuated the severity of pancreatitis in histological examination and accelerated pancreatic recovery. These effects were accompanied with a faster reduction in the AP-evoked increase in serum activity of amylase and lipase, the serum concentration of pro-inflammatory interleukin-1b, and the plasma level of D-Dimer. In addition, treatment with warfarin decreased pancreatic weight (an index of pancreatic edema) and improved pancreatic blood flow in rats with AP. The therapeutic effect was particularly pronounced after the administration of warfarin at a dose of 90 µg/kg. We conclude that treatment with warfarin accelerated regeneration of the pancreas and recovery in the course of cerulein-induced mild-edematous acute pancreatitis. [ABSTRACT FROM AUTHOR]

Melatonin (MEL) is produced and secreted by the pineal gland as well as the small intestine, liver, retina, lymphocytes, and melanocytes in the skin in both experimental animals as well as in humans. While pineal and retinas MEL is closely related to the light/dark cycle, the production of MEL by other so called extrapineal tissues is independent of such circadian rhythm. Among the primary mechanisms of action of MEL in humans, the most important are interaction of MEL with specific receptors (M1, M2, M3) and the MEL ‘scavenging’ activity against the formation of free oxygen metabolites as a result of MEL’s ability to transfer free electrons and stimulation of the expression of redox reaction enzymes. In addition, MEL binds to intracellular proteins such as calmodulin, thereby affecting the course of cell cycle, and it has been shown to activate of nuclear receptors belonging to the retinoid orphan receptors/retinoid Z receptors (ROR/RZR) subfamily. MEL exerts regulatory effects on the master clock regulating diurnal rhythms. This updated review presents current view on the synthesis and metabolism of MEL and the growing body of experimental evidence transferable to the practical medicine supporting a pleiotropic molecule beneficial effects on the health including protection against various organ abnormalities, including internal organs such as the liver. Although the beneficial effects of MEL in various types of liver damage have been well documented in experimental studies, there are relatively few studies on liver dysfunction in humans. Considering the worldwide obesity pandemic often associated with the occurrence of steatohepatitis and cirrhosis, the beneficial effects of MEL in liver pathology should be proven in randomized trials involving patients presenting with hepatic disorders. [ABSTRACT FROM AUTHOR]

Melatonin (N-acetyl-5-methoxytryptamine) is an indoleamine synthesized in vertebrates mainly in the pineal gland, and is known to be involved mainly in thermoregulation and control of the circadian rhythm. That indoleamine can affect the auto-, para- and endocrine pathways, regulating body functions and affecting the metabolism of animals and humans. In addition to the pineal gland, melatonin can be synthesized in many extra-pineal tissues, mainly in the gastrointestinal tract. Previous studies have shown that melatonin plays an important role in the defense system of the gastrointestinal mucosa, demonstrating a protective effect on the gastrointestinal tract and the acceleration of healing of chronic ulcers through the scavenging of reactive oxygen metabolites (ROS) and the activation of protective nitric oxide (NO) and vasodilator neuropeptides released from the sensory afferent neurons. The process of converting the melatonin precursor L-tryptophan into melatonin is already known, but not all aspects of this process for the synthesis of other metabolites of this pathway have been fully elucidated and this issue remains poorly understood. In this study, the conversion of L-tryptophan to melatonin and other metabolites was determined in gastric mucosa collected from rats with or without intragastric (i.g.) melatonin or L-tryptophan administration, both administered at a single dose of 50 mg/kg. For the determination of five metabolites of L-tryptophan: kynurenine, 5-hydroxytryptamine, 5-hydroxytryptophan, anthranilic acid, indole-3-acetic acid together with melatonin, we have modified the previously developed high-performance liquid chromatography (HPLC) method using a native fluorescence detection system and UV-VIS. The obtained results show that: 1) L-tryptophan is converted into melatonin in the gastric mucosa during the day, e.g. after eating a meal containing L-tryptophan, as it was imitated and confirmed by our study, in which this amino acid was administered directly to the stomach, 2) the gastric mucosa is capable of producing melatonin in much greater amounts than those recorded in the blood serum of rats given a single dose of L-tryptophan, and 3) apart from melatonin, the only serum levels of these five metabolites of the L-tryptophan metabolic pathway are detectable, while their level in the gastric mucosa is low and barely detectable under physiological conditions. Our present observations support the notion that the gastric mucosa is one of the main sources of melatonin production from L-tryptophan outside the pineal gland. [ABSTRACT FROM AUTHOR]

Although the natural niche for H. pylori (Hp) is the human stomach, for widespread infection to occur this microorganism may need to survive in the external environment. Molecular techniques such as polymerase (PCR) have revealed the presence of Hp DNA in water, indicating that this environment could act as a reservoir for this bacterium. The aim of this study was to analyse the occurrence of Hp in tap water from Cracow and to examine the relationship between 26 parameters and the presence of Hp DNA due to the lack of such information related to this issue in Poland. Additional aim of this study was to determine whether the correlation between Hp DNA detection and seasonal changes of water quality in 379 water samples collected from various water treatment plants (WTPs), could be found. Water samples were subjected to PCR for glmM and cagA genes. Ionic and organic composition of microelements were determined in accordance to Polish and ISO standards. The data obtained from tests show that 212 (55.96%) objects were Hp DNA (glmM) positive and among them 145 (68.40%) waters samples revealed expression of cagA. Linear Discriminant Analysis and Principal Component Analysis were used and provided that the selected variables (p < 0.05): colour, pH, conductivity at 25ºC, chlorides, nitrites, nitrates, phosphates, chlorates, chlorites, sulphates, free chlorine, sodium, magnesium, potassium, calcium, organic carbon, trichloromethane, bromodichloromethane, dibromochloroethane, total iron, ammonium ion, and ∑TMHs distinguished the water samples that contain Hp DNA and do not contain Hp DNA. We conclude that the ionic and organic composition of microelements in water might influence the presence of Hp. Thus, determination of the selected microelements may indirectly indicate or sometimes predict the presence of Hp in drinking water. [ABSTRACT FROM AUTHOR]

Gut-brain axis plays a central role in the regulation of stress related diseases such as irritable bowel syndrome (iBs) or inflammatory bowel disease (iBD). it is increasingly recognized that stress modulates gut microbiota community structure and activity and represents an important causal factor in dysbiosis. this study was designed to determine the effect of daily treatment with synbiotic (syngut) containing inulin, Lactobacillus acidophilus, Bifidobacterium lactisw51, Lactobacillus plantarumw21 and Lactococcus lactis applied i.g. at a dose of 50 mg/kg i.g. on the colonic damage and colonic mucosal blood flow in rats with experimentally induced tnBs-colitis that were additionally exposed or not to acute stress (episodes of cold restraint stress every other day before colitis induction). Control rats received daily treatment with vehicle (saline, i.g.) or mesalazine (50 mg/kg-d i.g.), the standard drug recommended in therapy of iBD. at the termination of tnBs colitis, the histologic evaluation of colonic mucosa, mucosal malonyldialdehyde (MDa) level and plasma concentrations of proinflammatory cytokines (tnf-a, iL-1ß) and adipokine adiponectin were assessed. the samples of colonic mucosa not involving colonic lesions and surrounding the flared mucosa were excised for the determination of mrna expression for proinflammatory biomarkers tnf-a, iL-1ß, iL-10 and Cox-2 as well as antioxidazing factors soD-1 and soD-2. finally, the gut microbial profiles were analyzed by 16s rrna sequencing at phylum, family and genus level. episodes of cold stress significantly aggravated the course of tnBs colitis, and significantly increased the release of proinflammatory cytokines as well as the significant increase in the MDa concentration has been observed as compared with non-stressed tnBs rats. these changes were followed by the significant fall in the CBf and plasma adiponectin levels and by the overexpression of mrna of proinflammatory biomarkers. synbiotic treatment with syngut significantly reduced the area of colonic lesions observed macroscopically and microscopically in rats with tnBs colitis with or without exposure to cold stress, significantly increased the CBf, normalized plasma adiponectin levels and significantly attenuated the release and colonic expression of proinflammatory cytokines and biomarkers. the analysis of the gut microbiota showed a significant reduction of microbial diversity (shannon index) in rats with tnBs colitis with or without exposure to stress. the therapy with syngut failed to significantly affect the alpha diversity. at the phylum level, the significant rise in Proteobacteria has been observed in stressed rats with tnBs colitis and this effects was attenuated by treatment with syngut. at family level, tnBs colitis alone or in combination with stress led to a significant decrease of sCfa producing bacterial taxa such as Ruminococaceae and Lachnospiraceae and syngut counteracted this effect. we conclude that: 1) cold stress exacerbates the gastrointestinal inflammation in experimental colitis; 2) the synbiotic therapy with syngut ameliorates the gut inflammation in rats with tnBs colitis combined with cold stress; 3) the beneficial effect of syngut is accompanied by increase of anti-inflammatory taxa such as Ruminococaceae and Lachnospiraceae, and 4) the modulation of gut microbiota with syngut alleviates stressrelated intestinal inflammation suggesting a potential usefulness of synbiotic therapy in intestinal disorders accompanied by stress in patients with iBD. [ABSTRACT FROM AUTHOR]

Gastric cancer (GC) originating from the lining of the stomach is one of the most frequent malignancies in humans. The most efficient method giving hope of full recovery from GC is gastric resection combined with adjuvant chemotherapy and radiotherapy. However, over 50% of patients after treatment suffer from recurrence and peritoneal metastasis. The bacteria Helicobacter pylori (Hp) is nowadays considered as the major pathogen capable of colonizing gastric mucosa. This bug causes deregulation of multiple signaling pathways including the activation of nuclear factor kappaB (NFκB) and Janus kinase/signal transducers and activators of transcription (JAK/STAT) responsible for inflammation and development of carcinogenic cascade. The pathomechanism of these changes remains little understood, but the Hp virulence factors affecting mainly gastric epithelium have been postulated. Nevertheless, the changes associated with inflammation progressing to cancer are not only limited to epithelial cells. The cells surrounding the tumor, mainly activated fibroblasts (CAFs - cancer-associated fibroblasts) create molecular microenvironment promoting tumorigenesis and cancer invasion. The downstream targets of STAT3, epithelial-mesenchymal transition-inducing transcription factors (EMT-TFs) are expressed in activated fibroblasts providing them with additional properties. Thus, our aim was to determine if the Hp strain expressing CagA and VacA cytotoxins may result in the activation/differentiation of rat gastric fibroblasts resulting in NFκB and STAT3 signaling, which could lead to EMTTFs expression and secretome responsible for inflammatory and EMT inducing microenvironment. In this study, gastric samples were harvested from 8-week-old Spraque-Dowley rats and the primary and secondary fibroblast cultures were established. The 70% confluent secondary fibroblast cultures were infected with 1 × 109 of live Hp expressing cytotoxins CagA VacA per dish and incubated in humidified atmosphere for 3, 24, 48 and 72 hours, before the conditioned media or the cells were used for endpoint experiments. As the control, fibroblast culture in DMEM with 10% FBS and antibiotics, free from Hp infection was used. The expression of mRNA for 18S (control), toll-like receptors: TLR2 and TLR4, STAT3, NFκB p65/Rel A, inhibitor of NF-κB (Iß), Snail and Twist was determined by RT-PCR. The protein expression of Snail and Twist was assessed by Western blot technique. The fibroblast supernatant was collected at 72 hours from non-infected and Hp (cagA+ vacA+)-infected culture and the concentrations of interleukin 8 (IL-8), hepatocyte growth factor (HGF) and stromal derived factor-1 (SDF-1) were measured by ELISA. In fibroblasts infected with Hp (cagA+ vacA+), the significant increase of mRNA expression for both, TLR2 and TLR4, as well as STAT3, NFκB/RelA subunit was observed already after 3 hours of fibroblasts infection with Hp strain compared with control non-infected fibroblasts. Simultaneously, the significant decrease of Iß mRNA has been noticed starting from 48 hours after the Hp infection of fibroblasts was carried out. The strong increase in the expression of Snail1 and Twist mRNA was recorded already at 3 hours in Hp-infected fibroblasts comparing to control non-infected fibroblasts and this increase persisted at 24 and 48 hours being the most pronounced at 72 hours post incubation with Hp. The expression of Snail1 protein was observed after 3 hours post Hp infection and this increase persisted throughout entire time periods upon Hp infection. In contrast, no detectable level of Twist protein expression was observed up to 72 hours postinfection neither in control conditions nor in fibroblasts co-infected with Hp. These changes in fibroblasts were accompanied by a significant increase in the release of HGF, SDF-1 and IL-8 determined in cell supernatants collected from Hp-infected fibroblasts. These data indicate that the activation/differentiation of rat gastric fibroblasts can occur directly by Hp releasing CagA and indirectly through TLR2 and TLR4 and these effects can be mediated by transcription factors NFκB and STAT3 signaling leading to rapid Snail1 protein expression. We conclude that NFκB and STAT3 signaling together with Snail1 protein expression may activate the secretome responsible for fibroblasts inflammatory and EMT-inducing microenvironment likely serving as prerequisite for GC development. [ABSTRACT FROM AUTHOR]