bluuebunny/crossref_metadata_2025 huggingface dataset:
HIP/PAP is an adhesive protein expressed in hepatocarcinoma, normal Paneth, and pancreatic cells
Authors: Christa L. , Carnot F. , Simon M. T. , Levavasseur F. , Stinnakre M. G. , Lasserre C. , Thepot D. , Clement B. , Devinoy E. , Brechot C.
Published: December 2017

Human hepatocarcinoma-intestine-pancreas (HIP) cDNA, isolated from a hepatocellular carcinoma, encodes a C-type lectin. According to published cDNA sequences, HIP protein is identical to human pancreatitis-associated protein (PAP). In these sequences, a putative signal peptide and the carbohydrate recognition domain (CRD) can be recognized. In the present study, we established transgenic mice to drive the production of soluble recombinant HIP/PAP protein in the milk of lactating animals; using this model, we showed that HIP/PAP protein was secreted after suitable cleavage of the potential signal peptide. Moreover, we also produced HIP/PAP protein by Escherichia coli cultures performed to generate specific antibodies. These antibodies enabled the detection of HIP/PAP protein in normal intestine and pancreas (both in endocrine and exocrine cells), e.g., intestinal neuroendocrine and Paneth cells, pancreatic islets of Langerhans, and acinar cells. HIP/PAP protein was also identified in the cytoplasm of tumoral hepatocytes but not in nontumoral hepatocytes. Finally, HIP/PAP protein activity was tested and we showed that HIP/PAP induced the adhesion of rat hepatocytes and bound strongly to extracellular matrix proteins (laminin-1, fibronectin), less strongly to type I and IV collagen, and not at all to heparan sulfate proteoglycan. In conclusion, these results showed that HIP/PAP protein was matured on secretion. We also demonstrated that HIP/PAP protein was specifically expressed in hepatocarcinoma cells and interacted with rat hepatocytes and the extracellular matrix. Taken overall, these results suggest that HIP/PAP protein may be of potential importance to liver cell differentiation/proliferation.
Incrimination of anaerobic bacteria in the induction of experimental colitis
Authors: Garcia-Lafuente A. , Antolin M. , Guarner F. , Crespo E. , Salas A. , Forcada P. , Laguarda M. , Gavalda J. , Baena J. A. , Vilaseca J. , Malagelada J. R.
Published: December 2017

Commensal bacteria may participate in the pathogenesis of bowel inflammation. We studied the role of bacteria from the rat colonic flora on transmural inflammation induced by 2,4,6-trinitrobenzenesulfonic acid (TNBS). First, bacterial translocation to the colonic wall after induction of colitis was assessed by microbiological and histological methods. Second, rats with a colonic segment excluded from fecal transit were prepared for recolonization with preselected bacteria and used to test the effects of different species on inflammation (eicosanoid release, tissue myeloperoxidase) and damage (histology). Six strains (three aerobes and three anaerobes) were identified in colonic tissue 24 h after induction of colitis. Acridine staining showed bacteria in necrotic areas of the mucosa and invading the submucosa. Rats with excluded colon and sterile culture of luminal washings showed mild inflammation and low mucosal damage in response to TNBS. Rats colonized with anaerobes showed significantly higher eicosanoid release than rats colonized with aerobes only. Moreover, submucosal-lesions were mostly observed in rats with anaerobes. Our findings suggest that colonic anaerobes play a key role in transmural inflammation.
Endogenous CCK disrupts the MMC pattern via capsaicin-sensitive vagal afferent fibers in the rat
Authors: Rodriguez-Membrilla A. , Vergara P.
Published: December 2017

A meal disrupts migrating motor complexes (MMC) in the rat intestine through stimulation of peripheral cholecystokinin (CCK)-B and central CCK-A receptors. The aim of this study was to determine pathways implicated in postprandial disruption of the MMC mediated by CCK. Sprague-Dawley rats were prepared with electrodes for electromyography in the small intestine, and ablation of vagal afferent C-fibers by capsaicin was carried out. Endogenous release of CCK was induced by oral administration of soybean trypsin inhibitor (SBTI). In control rats SBTI disrupted MMC and generated an irregular spiking activity that lasted longer than 3 h. Intravenous infusion of L-365,260 (2 x 10(-7) mol/kg) but not of L-364,718 (3 x 10(-9) mol/kg) restored the MMC pattern. In capsaicin-treated rats, SBTI did not modify fasting activity. Infusion of CCK octapeptide (CCK-8) at 3 x 10(-9) mol.kg-1.h-1 disrupted the MMC, although the response was quantitatively and qualitatively different from SBTI. The effect was reversed by intravenous infusion of L-364,718 or L-365,260 and intracerebroventricular infusion of L-364,718. In capsaicin-treated rats, the intracerebroventricular or intravenous infusion of L-364,718 inhibited CCK-8 effects. However, the intravenous infusion of L-365,260 did not reverse the MMC pattern. These results suggest that the disruption of the MMC mediated by CCK is due to stimulation of peripheral CCK-B receptors located in vagal afferent fibers. This initiates a reflex including stimulation of central CCK-A receptors. Exogenous CCK also stimulates peripheral CCK-A receptors not located in capsaicin-sensitive vagal afferent fibers.
Vasoactive intestinal peptide modulates T lymphocyte migration in Peyer's patches of rat small intestine
Authors: Miura S. , Serizawa H. , Tsuzuki Y. , Kurose I. , Suematsu M. , Higuchi H. , Shigematsu T. , Hokari R. , Hirokawa M. , Kimura H. , Ishii H.
Published: December 2017

Although vasoactive intestinal peptide (VIP) has been postulated to function in modulation of T cell trafficking, the exact mechanism has not been elucidated in vivo. In the present study, the effects of VIP on T lymphocyte migration were examined in rat Peyer's patches. T lymphocytes collected from intestinal lymph of rats were labeled with carboxyfluorescein diacetate succinimidyl ester and injected into the jugular vein. Peyer's patches of the recipient rats were observed with intravital fluorescence microscopy. In vivo intra-arterial infusion of or in vitro incubation with VIP did not affect the initial lymphocyte interaction with postcapillary venules of Peyer's patches. However, these treatments with VIP significantly inhibited transendothelial migration and also significantly blocked the interstitial migration of T cells and inhibited their subsequent appearance in the interfollicular lymphatics. Treatment with adenosine 3',5'-cyclic monophosphate (cAMP)-inducing agents resulted in similar inhibitory effect on T lymphocyte migration in Peyer's patches. In conclusion, VIP has significant inhibitory effects on T lymphocyte migration in Peyer's patches, possibly mediated by elevation of the intracellular cAMP concentrations.
Effects of chemical sympathectomy and sensory nerve ablation on experimental colitis in the rat
Authors: McCafferty D. M. , Wallace J. L. , Sharkey K. A.
Published: December 2017

We assessed the effects of primary afferent nerve ablation (systemic treatment with capsaicin during adult or neonatal periods), primary afferent nerve activation (intracolonic capsaicin), and sympathectomy [6-hydroxydopamine (6-OHDA)] on the development of colitis induced by 2,4,6-trinitrobenzenesulfonic acid (TNBS) in rats. We also examined whether lidocaine was effective after ablation of primary afferent nerves or sympathectomy. Colitis was assessed by macroscopic scoring, measurement of myeloperoxidase (MPO) activity, and histology. Systemic capsaicin treatment in adults increased the macroscopic damage score. Capsaicin treatment of neonates did not significantly increase damage score or MPO activity compared with vehicle-treated controls. However, all capsaicin-treated groups had a higher mortality. Intracolonic capsaicin treatment did not alter the severity of colitis. Chemical sympathectomy resulted in a decreased damage score and improved histology compared with controls. In 6-OHDA pretreated rats, lidocaine administration reduced the macroscopic and histological scores and MPO activity almost to control levels. However, lidocaine administration in capsaicin-treated rats attenuated the macroscopic damage but did not improve MPO activity or histology. These data suggest that capsaicin-sensitive nerves play a protective role in experimental colitis and sympathetic nerves contribute to the development of colitis. The beneficial effects of lidocaine appear to be due primarily to its action on enteric nerves.
Increased intestinal muscle contractility and worm expulsion in nematode-infected mice
Authors: Vallance B. A. , Blennerhassett P. A. , Collins S. M.
Published: December 2017

Intestinal nematode infections are accompanied by mucosal inflammation and an increase in propulsive motor activity that may contribute to parasite eviction from the gut. To examine whether differences in worm expulsion correspond to the increased intestinal muscle contractility that accompanies nematode infection, we studied mice with genetically determined differences in their ability to expel the nematode parasite Trichinella spiralis. Specifically, we examined isometric contraction of longitudinal muscle, worm counts, and inflammation, as measured by myeloperoxidase activity, in two strains of mice infected with T. spiralis. The strong responder strain, NIH Swiss, expelled the parasites by day 16 postinfection, whereas the poorer responding B10.BR strain was still heavily infected by day 21 postinfection. However, both strains developed similar increases in jejunal myeloperoxidase activity. Both strains demonstrated increased isometric tension development after infection, but peak tension occurred earlier in NIH Swiss mice (day 8 vs. day 12 postinfection) and was of significantly greater magnitude than in B10.BR mice. We conclude that the ability to expel T. spiralis from the small bowel is not related to the degree of granulocyte-dependent mucosal inflammation but is reflected in the magnitude of the accompanying increase in force generation by intestinal smooth muscle.
Protective effects of interleukin-11 in a murine model of ischemic bowel necrosis
Authors: Du X. , Liu Q. , Yang Z. , Orazi A. , Rescorla F. J. , Grosfeld J. L. , Williams D. A.
Published: December 2017

The present study examined the effect of interleukin-11 (IL-11) in a murine model of bowel ischemia (BI). Prophylactic IL-11 administration in BI mice (induced by occluding the superior mesenteric artery for 90 min) was associated with significantly decreased morbidity and mortality. IL-11-treated mice demonstrated rapid recovery of intestinal mucosa as evidenced by an increase in mitotic activity and suppression of apoptosis in intestinal crypt cells as well as increased peripheral platelet and leukocyte counts primarily due to an increase in peripheral lymphocyte number in BI mice. In contrast to vehicle-treated mice, which uniformly developed thrombocytopenia after ischemic injury, no IL-11-treated BI mice developed thrombocytopenia during the experimental period. These data suggest a role for IL-11 in the treatment of gastrointestinal mucosal diseases due to a wide variety of causative injuries.
Prostaglandins induce proliferation of rat hepatocytes through a prostaglandin E2 receptor EP3 subtype
Authors: Hashimoto N. , Watanabe T. , Ikeda Y. , Yamada H. , Taniguchi S. , Mitsui H. , Kurokawa K.
Published: December 2017

We characterized the proliferative action of prostaglandins (PGs) in relation to their membrane receptors on rat hepatocytes in primary culture. PGs in the order 16,16-dimethyl PGE2 > PGE2 > PGF2alpha >> PGD2 augmented epidermal growth factor (EGF)/insulin-induced DNA synthesis, assessed by [(3)H]thymidine incorporation, in a concentration-dependent manner, whereas PGs alone did not stimulate basal DNA synthesis without EGF and insulin. The cells exhibited [(3)H]PGE2 binding sites that were displaced by unlabeled PGs in the order PGE1 = PGE2 > PGF2alpha > PGD2. PGE2 inhibited glucagon-stimulated adenosine 3',5'-cyclic monophosphate (cAMP) accumulation concentration dependently. The mean effective concentration for DNA synthesis, median inhibitory concentration for cAMP accumulation, and dissociation constant for [(3)H]PGE2 binding at 25 degrees C were almost identical (approximately 70 nM). Treatment of the cells with pertussis toxin (100 ng/ml), which ADP-ribosylated most of the 41-kDa substrate, abolished the proliferative effects of PGs. We detected the expression of mRNA of the EP3 subtype PGE2 receptor using reverse transcription-polymerase chain reaction. Moreover, an EP3 agonist, enprostil, but not the EP1 agonist 17-phenyl-trinor-PGE2 or the EP2/EP4 agonist 11-deoxy-PGE1, stimulated EGF/insulin-induced DNA synthesis. These results indicate that PGs act as comitogenic growth factors through the EP3 subtype PGE2 receptor coupled with G(i) protein in cultured rat hepatocytes.
Gastric emptying and gastrointestinal transit during lactation in rats
Authors: Chen T. S. , Doong M. L. , Wang S. W. , Tsai S. C. , Lu C. C. , Shih H. C. , Chen Y. H. , Chang F. Y. , Lee S. D. , Wang P. S.
Published: December 2017

Female sex hormones can influence gastrointestinal function. To understand whether postpartum changes in female sex hormones may affect such function, gastric emptying and gastrointestinal transit were measured in rats on days 1-2, 10, 15, and 21 of lactation, on day 7 postweaning, and at the nonpregnant diestrous stage. Gastric emptying and gastrointestinal transit were assessed in conscious rats 15 min after intragastric instillation of a test meal containing charcoal and (51)Cr. The results showed that gastric emptying was increased throughout the first 2 wk of lactation, with a gradual decrease as lactation proceeded toward weaning, and returned to the level of the virgin rats by 1 wk postweaning. Gastrointestinal transit was greater in the early stage of lactation and was related to gastric emptying (P < 0.001). Increases in gastric emptying and intestinal length were correlated with lactation (P < 0.001) and plasma prolactin levels (P < 0.05) but not with plasma progesterone or estradiol levels. We concluded that the sex steroid hormones associated with lactation do not mediate a change in gastric emptying and gastrointestinal transit during lactation.
Cellular localization of mRNAs for prostaglandin E receptor subtypes in mouse gastrointestinal tract
Authors: Morimoto K. , Sugimoto Y. , Katsuyama M. , Oida H. , Tsuboi K. , Kishi K. , Kinoshita Y. , Negishi M. , Chiba T. , Narumiya S. , Ichikawa A.
Published: December 2017

Regional and cellular distribution of mRNAs for prostaglandin E (PGE) receptor subtypes was investigated in the mouse gastrointestinal tract by in situ hybridization. Strong signals for EP1 transcripts were detected in cells of the muscularis mucosae layer, especially in the body of the stomach. Intense signals for EP3 transcripts were detected in neurons of the myenteric ganglia throughout the tract. Moderate EP3 mRNA expression was also observed in fundic gland epithelial cells, except for surface mucous cells in the stomach. Expression of EP4 mRNA was moderate in surface epithelial cells of the corpus and in glands from the surface to the base of the antrum. Strong EP4 signals were observed in the epithelium in the duodenum, jejunum, and ileum. In the ileum, signals were only observed in the upper part of the villi. However, no or weak signals for EP2 transcripts were detected. These findings suggest that PGE2 modulates various gastric or intestinal functions via at least three different PGE receptors.
Common bile duct ligation in the rat: a model of intrapulmonary vasodilatation and hepatopulmonary syndrome
Authors: Fallon M. B. , Abrams G. A. , McGrath J. W. , Hou Z. , Luo B.
Published: December 2017

Hepatopulmonary syndrome (HPS) causes impaired oxygenation due to intrapulmonary vasodilatation in patients with cirrhosis. Chronic common bile duct ligation (CBDL) in the rat results in gas-exchange abnormalities similar to HPS, but intrapulmonary vasodilatation has not been evaluated. We assess intrapulmonary vasodilatation, measured in vivo, after CBDL. Sham, 2- and 5-wk CBDL, and 3-wk partial portal vein ligated (PVL) rats had hepatic and lung injury, portal pressure, and arterial blood gases assessed. The pulmonary microcirculation was evaluated by injecting microspheres (size range 5.5-10 microm) intravenously and measuring the size and number of microspheres bypassing the lungs in arterial blood. CBDL animals developed progressive hepatic injury and portal hypertension accompanied by gas-exchange abnormalities and intrapulmonary vasodilatation. PVL animals, with a similar degree of portal hypertension, did not develop intrapulmonary vasodilatation or abnormal gas exchange. No lung injury was observed. CBDL, but not PVL, causes progressive intrapulmonary vasodilatation, which accompanies worsening arterial gas exchange. These findings validate CBDL as a model to study HPS.
Substance P and bradykinin stimulate plasma extravasation in the mouse gastrointestinal tract and pancreas
Authors: Figini M. , Emanueli C. , Grady E. F. , Kirkwood K. , Payan D. G. , Ansel J. , Gerard C. , Geppetti P. , Bunnett N.
Published: December 2017

Neurogenic inflammation is mediated by release of tachykinins from sensory nerves, which stimulate plasma extravasation from postcapillary venules. Because there are conflicting results regarding the importance of neurogenic inflammation in the gastrointestinal tract, we quantified plasma extravasation using Evans blue and identified sites of the leak using Monastral blue in the mouse. Substance P and bradykinin stimulated extravasation from postcapillary venules in the stomach, small and large intestine, pancreas, urinary bladder, trachea, and skin by two- to sevenfold by interacting with NK1 and B2 receptors, respectively. Stimulation of sensory nerves with capsaicin also induced extravasation. Capsaicin- and bradykinin-stimulated extravasation was attenuated by an NK1-receptor antagonist and is thus mediated by release of tachykinins and activation of the NK1 receptor. We conclude that 1) substance P stimulates extravasation in the gastrointestinal tract and pancreas of mice by interacting with the NK1 receptors, and 2) capsaicin and bradykinin induce plasma extravasation by stimulating tachykinin release from sensory nerves. Thus neurogenic mechanisms mediate inflammation in the gastrointestinal tract and pancreas of the mouse.
Interleukin-4 modulates cholinergic neural control of mouse small intestinal longitudinal muscle
Authors: Goldhill J. , Morris S. C. , Maliszewski C. , Urban J. F. , Funk C. D. , Finkelman F. D. , Shea-Donohue T.
Published: December 2017

Interleukin-4 contributes to expulsion of certain gastrointestinal parasites and causes intestinal mucosal mastocytosis. Because mast cell-derived mediators are spasmogenic, potentially causing parasitic expulsion, we investigated the effect of interleukin-4 on smooth muscle and the mast cell and mediator dependency of this effect. BALB/c, mast cell-deficient W/Wv mice, 5-lipoxygenase-efficient mice, and their littermate controls were injected with interleukin-4-anti-interleukin-4 antibody complexes that chronically increase serum interleukin-4 levels. Mid-small intestinal segments, hung longitudinally in organ baths, were stimulated electrically or by agonists. The cholinergic response to electrical field stimulation was significantly increased by interleukin-4 treatment in BALB/c but not W/Wv mice. The enhanced cholinergic contraction was not due to increased acetylcholine responsiveness but was dependent on leukotriene D4, since it was reversed by leukotriene D4 receptor antagonism, and not observed in 5-lipoxygenase knock-out mice. Leukotriene D4 responsiveness was unaffected by interleukin-4 treatment. We conclude that interleukin-4 amplifies cholinergic excitation through a mast cell and leukotriene D4-dependent mechanism.
Endothelin-activated calcium signaling in enteric glia derived from neonatal guinea pig
Authors: Zhang W. , Sarosi G. , Barnhart D. , Yule D. I. , Mulholland M. W.
Published: December 2017

The ability of guinea pig enteric glia to respond to endothelins was examined using fura 2-based digital microscopy in glial cells derived from guinea pig taenia coli. Each isoform of endothelin (ET-1, ET-2, ET-3) evoked dose-dependent and equipotent increases in intracellular Ca2+ concentration ([Ca2+]i) and in percentage of cells responding, 4alaEt-1, an ETB receptor agonist, elicited similar [Ca2+]i increments. BQ-788, an ETB antagonist, inhibited [Ca2+]i responses to endothelin. Preincubation of glia with U-73122 a phospholipase C inhibitor, abolished the [Ca2+]i response to ET-3 exposure. Thapsigargin also eliminated ET-3-evoked Ca2+ signaling. The inositol 1,4,5-trisphosphate (IP3) receptor antagonist heparin, introduced into glial cells by radio frequency electroporation, blocked [Ca2+]i responses to ET-3 (100 nM) in 63% of glia. Sustained elevation in [Ca2+]i was abolished by removal of Ca2+ from the buffer and inhibited 85. -3% by Ni2+ (1 mM). Preincubation of glia with 100 nM phorbol 12-myristate 13-acetate (24 h) also inhibited sustained increments in [Ca2+]i by 87%. The presence of IP3 receptors in enteric glia was confirmed by immunofluorescent confocal microscopy.
Interleukin-15 signals T84 colonic epithelial cells in the absence of the interleukin-2 receptor beta-chain
Authors: Stevens A. C. , Matthews J. , Andres P. , Baffis V. , Zheng X. X. , Chae D. W. , Smith J. , Strom T. B. , Maslinski W.
Published: December 2017

Interleukin-15 (IL-15) shares many biological functions with interleukin-2 (IL-2) due to common receptor components. IL-15 binds to the IL-2 receptor (IL-2R) beta-chain and the common gamma-chain receptor in addition to one other IL-15 binding receptor protein (IL-15R alpha). Both IL-2R beta- and gamma-chains are required to promote cell growth in hematopoietic cells. The colonic cryptlike epithelial cell line T84 contains the common gamma-chain but lacks the IL-2R beta-chain. We report IL-15R alpha-chain mRNA in T84 cells with the use of reverse transcriptase-polymerase chain reaction. T84 and normal colonic epithelial cells bind a FLAG-IL-15 fusion protein in immunoperoxidase and flow cytometric experiments. In addition, IL-15, but not IL-2, accelerates and enhances the development of transepithelial resistance across T84 monolayers in a dose-dependent fashion. We conclude that normal and T84 colonic epithelial cells express IL-15R alpha and are able to bind IL-15. IL-15 can deliver a nonproliferative functional signal in the absence of IL-2R beta-chain in T84 cells.
Candidate canine enterogastrones: acid inhibition before and after vagotomy
Authors: Lloyd K. C. , Amirmoazzami S. , Friedik F. , Heynio A. , Solomon T. E. , Walsh J. H.
Published: December 2017

The relative contributions of several gut-derived peptides as enterogastrones known to be released in response to a fatty meal and to inhibit acid secretion have not previously been compared directly. We determined the acid-inhibitory activities of increasing intravenous doses of several peptides before and after highly selective vagotomy (HSV) during intragastric titration of a peptone meal in dogs. Before HSV, threshold inhibitory doses of peptide YY (PYY), cholecystokinin (CCK), and secretin were 5, 7, and 10 pmol.kg-1.h-1, respectively, whereas neurotensin, glucagon-like peptide-1 (GLP-1), and oxyntomodulin failed to inhibit acid secretion at doses up to 1,000 pmol.kg-1.h-1. The calculated dose producing 50% acid inhibition (ID50) of secretin (62 pmol.kg-1.h-1) was one-half that of PYY (128 pmol.kg-1.h-1). Maximal (90%) acid inhibition was produced by 100 pmol.kg-1.h-1 secretin and 500 pmol.kg-1.h-1 PYY. The highest dose of CCK that did not cause vomiting (100 pmol.kg-1.h-1) inhibited peptone-stimulated acid output by only 60%. After HSV, 500 pmol.kg-1.h-1. PYY and 200 pmol.kg-1.h-1 CCK failed to inhibit acid output by more than 50%. Threshold doses for inhibition by PYY and CCK were 200 and 100 pmol.kg-1.h-1, respectively. Secretin remained a potent inhibitor after HSV, with an ID50 of 80 pmol.kg-1.h-1 and a threshold dose of 10 pmol.kg-1.h-1. HSV also failed to affect inhibition caused by somatostatin. This study has shown that PYY and secretin are somewhat more potent and efficacious inhibitors of acid secretion than CCK but that all three peptides are far more active than GLP-1, neurotensin, and oxyntomodulin. PYY and CCK inhibit acid secretion in large part through vagal innervation of the gastric fundus, but the inhibitory effects of secretin are independent of fundic vagal innervation.
Taurochenodeoxycholic acid ameliorates and ursodeoxycholic acid exacerbates small intestinal inflammation
Authors: Uchida A. , Yamada T. , Hayakawa T. , Hoshino M.
Published: December 2017

Intraluminal bacteria, food intake, and bile play important roles in indomethacin-induced small intestinal inflammation in rats. Tauroursodeoxycholic acid (TUDCA) and ursodeoxycholic acid (UDCA) inhibit hydrophobic bile acid-induced damage in various types of cells. We investigated the effects of these bile acids along with the possible influence of other bile acids on this model of inflammation. Clinical and intestinal inflammatory parameters and bile secretion were assessed after 7-day dietary bile acid pretreatments and subsequent indomethacin injections. UDCA significantly enhanced indomethacin-associated reductions in food intake and body weight, increases in gross inflammatory scores and myeloperoxidase activity, and the shortening of small intestinal length. Taurochenodeoxycholic acid (TCDCA) significantly normalized the clinical inflammatory parameters, prevented indomethacin-induced increases in the biliary contents of secondary bile acids and hydrophobicity index, and tended to attenuate the intestinal inflammation. Although elevated biliary levels of muricholic acids and a decreased hydrophobicity index were evident before indomethacin injection in the TCDCA case, these alterations could not explain the TCDCA-mediated protection. Dietary TCDCA attenuates whereas UDCA exacerbates intestinal inflammation in this model. Alterations in the bile composition (increases in UDCA and chenodeoxycholic acid) may explain the observed modification effects.
Effects of the inflammatory mediator prostaglandin E2 on myenteric neurons in guinea pig ileum
Authors: Dekkers J. A. , Akkermans L. M. , Kroese A. B.
Published: December 2017

The effects of the inflammatory mediator prostaglandin E2 (PGE2) on myenteric neurons were investigated by intracellular recordings in a conventional plexus preparation. Bath application of PGE2 (1-1,000 nM) evoked a concentration-dependent and reversible slow depolarization and an augmentation of excitability in 23 of 26 AH and 12 of 13 S neurons. The amplitude of the slow depolarization ranged from 4 +/- 1 mV at 1 nM to 13 +/- 3 mV at 1 microM in S and AH neurons. In AH neurons, PGE2 evoked an increase in membrane resistance and a reduction of afterhyperpolarization. In S neurons, PGE2 evoked either an increase or a decrease in membrane resistance. PGE2 slightly reduced the amplitude of electrically evoked fast excitatory postsynaptic potentials and had no effect on slow excitatory postsynaptic potentials. Moreover, PGE2 evoked bursts of fast excitatory postsynaptic potentials and action potentials in S neurons, indicative of cyclical neural activity in the myenteric plexus. It is concluded that the inflammatory mediator PGE2 can act as an excitatory neuromodulator of gastrointestinal motility through direct action on neurons in the myenteric plexus.
Adaptive Kupffer cell alterations after femur fracture trauma in rats
Authors: Huynh T. , Baker C. C. , Bracey L. W. , Lemasters J. J.
Published: December 2017

Because Kupffer cells constitute the largest fixed macrophage population and reside at a strategic position in hepatic sinusoids, interacting with hepatocytes, circulating cells, and mediators from the gut, they may be important in the inflammatory response after injury. This study examined the effect of remote tissue injury on Kupffer cell function. Femurs of Sprague-Dawley rats were fractured under anesthesia. Subsequently, their livers were perfused for measurement of oxygen consumption and the isolation and culture of Kupffer cells. At 2 and 48 h after femur fracture, hepatic oxygen consumption increased 17 and 19%, respectively. Gadolinium chloride pretreatment to ablate Kupffer cells blocked this increase of hepatic oxygen consumption after femur fracture but had no effect in sham-operated animals. In Kupffer cells isolated and cultured 2 h after femur fracture, superoxide formation stimulated by phorbol ester increased eightfold, phagocytosis increased fourfold, and lipopolysaccharide (LPS)-stimulated prostaglandin E2 increased sixfold in comparison to sham-operated controls. In contrast, LPS-stimulated tumor necrosis factor-alpha and nitric oxide production decreased 50 and 60%, respectively. These data show that peripheral trauma rapidly induces changes in hepatic macrophages characterized by adaptation to a more antimicrobial and less proinflammatory phenotype.
Somatostatin inhibits gastrin release and acid secretion by activating sst2 in dogs
Authors: Lloyd K. C. , Amirmoazzami S. , Friedik F. , Chew P. , Walsh J. H.
Published: December 2017

Somatostatin is a potent inhibitor of gastrin-stimulated acid secretion by activation of somatostatin receptor type 2 (sst2) in vivo, probably in part by blocking gastrin-stimulated histamine release from enterochromaffin-like cells expressing sst2. We propose that activation of sst2 may also regulate meal-stimulated acid secretion by blocking gastrin release from antral G cells. Using peptide analogs relatively selective for sst2 (NC-8-12), sst3 (BIM-23058), and sst5 (BIM-23052), we tested this hypothesis in two ways: first, in vivo by measuring plasma gastrin release during meal-stimulated acid secretion in dogs, and second, in vitro by measuring bombesin-stimulated gastrin release from an enriched culture of canine antral G cells. In vivo, a low dose (0.05 nmol.kg-1.h-1) of NC-8-12 inhibited acid secretion 56 +/- 16% without blocking gastrin release. A higher dose (1 nmol.kg-1.h-1) of NC-8-12 abolished acid secretion and inhibited gastrin release by 61 +/- 4%, whereas the highest dose (5 nmol.kg-1.h-1) inhibited gastrin release by 84 +/- 3%. Only the highest doses (5 nmol.kg-1.h-1) of BIM-23058 and BIM-23052 significantly inhibited gastrin release and acid secretion. In vitro, NC-8-12 (10(-9) M) reduced bombesin-stimulated gastrin release from antral G cells by 49 +/- 5%, whereas BIM-23058 and BIM-23052 were at least 100-fold less effective. These results indicate that somatostatin activation of sst2, but not sst3 or sst5, is the major pathway for somatostatin-induced inhibition of meal-stimulated gastrin release and acid secretion.
Intestinal absorption of undegraded proteins in men: presence of bromelain in plasma after oral intake
Authors: Castell J. V. , Friedrich G. , Kuhn C. S. , Poppe G. E.
Published: December 2017

The human adult intestinal epithelium has traditionally been described as nonpermeable to proteins. However, indirect evidence suggests that reduced absorption of undegraded proteins might take place under physiological conditions. Using bromelain (an enzyme obtained from pineapple stems) as a model protein, we studied the extent of this mucosal permeation in 19 healthy men. The protein was detected in plasma by immunoassay and by its proteolytic activity after oral administration. The estimated plasma half-life was 6–9 h. After oral multidosing (3 g/day), plasma concentration reached as much as 5,000 pg/ml by 48 h. From the plasma concentration curve, it could be estimated that an average of 10.8 micrograms of bromelain was present in plasma in the 3- to 51-h period. The presence of undegraded bromelain in plasma was shown unequivocally by immunoprecipitation of plasma samples with antibromelain antibodies, followed by gel electrophoresis and immunodetection. Moreover, the enzyme retained its biological activity, at least in part. Circulating bromelain was found associated with alpha 2-macroglobulin and alpha 1-antichymotrypain. The results of this work confirm the existence of a small but significant intestinal transport of undegraded proteins in healthy men.
Bovine pancreatic duct cells express cAMP- and Ca(2+)-activated apical membrane Cl- conductances
Authors: al-Nakkash L. , Cotton C. U.
Published: December 2017

Secretion of salt and water by the epithelial cells that line pancreatic ducts depends on activation of apical membrane Cl- conductance. In the present study, we characterized two types of Cl- conductances present in the apical cell membrane of bovine pancreatic duct epithelial cells. Primary cultures of bovine main pancreatic duct epithelium and an immortalized cell line (BPD1) derived from primary cultures were used. Elevation of intracellular adenosine 3',5'-cyclic monophosphate (cAMP) or Ca2+ in intact monolayers of duct epithelium induced sustained anion secretion. Agonist-induced changes in plasma membrane Cl- permeability were accessed by 36 Cl- efflux, whole cell current recording, and measurements of transepithelial Cl- current across permeabilized epithelial monolayers. Elevation of intracellular cAMP elicited a sustained increase in Cl- permeability, whereas elevation of intracellular Ca2+ induced only a transient increase in Cl- permeability. Ca(2+)- but not cAMP-induced increases in Cl- permeability were abolished by preincubation of cells with the Ca2+ buffer 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid, tetra(acetoxymethyl) ester (BAPTA-AM). N-phenylanthranilic acid (DPC; 1 mM) and glibenclamide (100 microM), but not 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS; 500 microM), inhibited the cAMP-induced increase in Cl- permeability. In contrast, DPC and DIDS, but not glibenclamide, inhibited the Ca(2+)-induced increase in Cl- permeability. We conclude from these experiments that bovine pancreatic duct epithelial cells express at least two types of Cl- channels, cAMP and Ca2+ activated, in the apical cell membrane. Because the Ca(2+)-activated increase in Cl- permeability is transient, the extent to which this pathway contributes to sustained anion secretion by the ductal epithelium remains to be determined.
5-HT-induced colonic contractions: enteric locus of action and receptor subtypes
Authors: Graf S. , Sarna S. K.
Published: December 2017

The role of 5-hydroxytryptamine (5-HT), its enteric locus of action, and the receptor subtypes involved in the stimulation of in vivo phasic contractions in the colon were investigated by close intra-arterial infusions in conscious dogs. The contractile response to 5-HT was blocked completely by prior close intra-arterial infusion of atropine and reduced significantly by prior close intra-arterial infusions of tetrodotoxin and hexamethonium. The contractile response was, however, enhanced by the inhibition of nitric oxide (NO) synthase by a prior close intra-arterial infusion of N omega-nitro-L-arginine methyl ester. Prior close intra-arterial infusions of 5-HT1A/5-HT1B, 5-HT2A, 5-HT2C, and 5-HT4 receptor antagonists had no significant effect on the contractile response to 5-HT. By contrast, 5-HT3 receptor antagonist significantly and dose dependently inhibited the contractile response to 5-HT. We conclude that the in vivo phasic contractile response to 5-HT in the colon is mediated mainly by 5-HT3 receptors located on pre- and postsynaptic cholinergic enteric neurons. 5-HT receptors may also be localized on nonadrenergic, noncholinergic inhibitory motoneurons that use NO as a neurotransmitter.
Role of kinases and phosphatases in the regulation of fluid secretion and Cl-/HCO3- exchange in cholangiocytes
Authors: Alvaro D. , Mennone A. , Boyer J. L.
Published: December 2017

The role of protein kinase A (PKA), protein kinase C (PKC), and protein phosphatases in the process of secretin stimulation of fluid and bicarbonate secretion from biliary epithelium was examined using a novel isolated bile duct unit (IBDU) model from rat liver. Sp-adenosine 3',5'-cyclic monophosphothiolate (Sp-cAMPS), 100 microM, a PKA-specific agonist, significantly increased secretion during a 30-min perfusion (+61%, P < 0.01). In contrast, preincubation and perfusion of Rp-cAMPS, 100 microM, a specific PKA inhibitor, reduced the ability of secretin to stimulate both fluid secretion (111 vs. 25%; P < 0.01) and Cl-/HCO3- exchanger activity (80 vs. 28%). Neither the PKC agonist phorbol 12-myristate 13-acetate, 10 microM, nor the PKC antagonist staurosporine showed any effect on either basal or secretin-stimulated fluid secretion or Cl-/HCO3- exchange activity in IBDU. Okadaic acid, a specific inhibitor of protein phosphatases 1 and 2A, also had no effect on basal fluid secretion or on the basal activity of the Cl-/HCO3- exchanger. However, okadaic acid resulted in persistence of secretion after removal of secretin, in contrast to the reduction in secretion observed in controls. These findings indicate that PKA but not PKC is involved in the signal transduction of secretin-stimulated fluid secretion and Cl-/HCO3- exchange activity in rat bile duct epithelium, a process inactivated by dephosphorylation by protein phosphatases 1 and/or 2A.
Survival of human pancreatic enzymes during small bowel transit: effect of nutrients, bile acids, and enzymes
Authors: Holtmann G. , Kelly D. G. , Sternby B. , DiMagno E. P.
Published: December 2017

The activity of pancreatic enzymes declines during aboral intestinal transit. We tested the hypothesis that survival of pancreatic enzyme activities during intestinal transit is affected by amounts or concentrations of calories, nutrients, bile acids, or pancreatic enzymes entering the segments of the small intestine. An oroileal tube was placed in 26 healthy humans. The tube had duodenal, jejunal, and ileal infusion ports for nonabsorbable markers and aspiration ports in the distal duodenum, distal jejunum, and distal ileum. Four infusates of different proportions of protein, fat, and carbohydrate were infused continuously into the duodenum at 40, 90, and 160 kcal/h. Of the nutrients infused into the proximal duodenum, 21 +/- 3, 51 +/- 7, and 39 +/- 5% of fat, protein, and carbohydrate, respectively, were delivered to the distal duodenum. During duodenoileal transit, lipase, chymotrypsin, amylase, and trypsin lost 71 +/- 5, 63 +/- 5, 43 +/- 7, and 38 +/- 9% of activity, respectively (P < 0.01 vs. distal duodenum). During duodenojejunal transit, the activity of each enzyme decreased more than 35% (P < 0.01 vs. distal duodenum), and infusion of more calories into the duodenum improved survival of all enzymes except trypsin (P < 0.05). During jejunoileal transit, greater amounts and concentrations of calories and carbohydrate improved survival of only lipolytic activity (P < 0.01, P < 0.05, respectively), and loss of lipolytic activity correlated directly with delivery of bile acids (r = 0.56, P = 0.05) and chymotrypsin (r = 0.80, P = 0.001) to the distal jejunum. We conclude that intraluminal nutrients increase survival of enzyme activities in the proximal intestine. After absorption of nutrients, the action of chymotrypsin and bile acids decrease lipolytic activity more than activity of other enzymes.
IV. Controlled spatiotemporal expression of transgenes: new tools to study normal and pathological states
Authors: Robine Sylvie , Jaisser Frédéric , Louvard Daniel
Published: December 2017

The gut epithelium represents a dynamic, well-organized developmental system for examining self-renewal, differentiation, repair, and tumorigenesis. The apical pole of the enterocytes, the brush border, is composed of an array of well-organized actin microfilaments that support the plasma membrane. Villin, one actin-binding protein that contributes to the assembly and dynamics of the microvillus bundle, exhibits special features such as restricted tissue specificity and early expression in the immature crypt cells. The regulatory elements of the villin gene are suitable to control the expression of transgenes in intestinal cells. Engineering genetically modified animals by classic transgenesis using the villin promoter or by gene targeting in the villin locus will allow the establishment of animal models that may recapitulate human intestinal disorders.
Fibronectin and cytokines increase JNK, ERK, AP-1 activity, and transin gene expression in rat hepatic stellate cells
Authors: Poulos John E. , Weber Jason D. , Bellezzo Joseph M. , Di Bisceglie Adrian M. , Britton Robert S. , Bacon Bruce R. , Baldassare Joseph J.
Published: December 2017

Cytokines, growth factors, and alterations in the extracellular matrix composition may play a role in maintaining hepatic stellate cells (HSC) in the activated state that is responsible for hepatic fibrogenesis. However, the signal transduction pathways that are stimulated by these factors in HSC remain to be fully elucidated. Recent evidence indicates that the mitogen-activated protein kinase (MAPK) family, including c-Jun NH2-terminal kinase (JNK) and extracellular signal-regulated kinase (ERK), plays an important role in the cellular response to stress. The aims of this study were to investigate whether fibronectin (FN) or the inflammatory cytokines interleukin-1α (IL-1α) and tumor necrosis factor-α (TNF-α) activate JNK, ERK, and AP-1 activity in HSC and induce the gene expression of the matrix metalloproteinase transin. Treatment of HSC with FN resulted in an up to 4.5-fold increase in ERK activity and a 2.1-fold increase in JNK activity. IL-1α and TNF-α produced up to a fourfold increase in JNK activity and a twofold increase in ERK activity. We then compared the effects of FN, IL-1α, and TNF-α on AP-1 activity and metalloproteinase mRNA induction. All three compounds increased AP-1 binding and promoter activity, and transin mRNA levels were increased 1.8-fold by FN, 2.2-fold by IL-1α, and 2.8-fold by TNF-α. Therefore, FN and inflammatory cytokines increase MAPK activity, stimulate AP-1 activity, and increase transin gene expression in HSC. Signal transduction pathways involving the MAPK family may play an important role in the regulation of matrix metalloproteinase expression by cytokines and FN in HSC.
Epithelial cell kinase-B61: an autocrine loop modulating intestinal epithelial migration and barrier function
Authors: Rosenberg Ian M. , Göke Michael , Kanai Michiyuki , Reinecker Hans-Christian , Podolsky Daniel K.
Published: December 2017

Epithelial cell kinase (Eck) is a member of a large family of receptor tyrosine kinases whose functions remain largely unknown. Expression and regulation of Eck and its cognate ligand B61 were analyzed in the human colonic adenocarcinoma cell line Caco-2. Immunocytochemical staining demonstrated coexpression of Eck and B61 in the same cells, suggestive of an autocrine loop. Eck levels were maximal in preconfluent cells. In contrast, B61 levels were barely detectable in preconfluent cells and increased progressively after the cells reached confluence. Caco-2 cells cultured in the presence of added B61 showed a significant reduction in the levels of dipeptidyl peptidase and sucrase-isomaltase mRNA, markers of Caco-2 cell differentiation. Cytokines interleukin-1β (IL-1β), basic fibroblast growth factor, IL-2, epidermal growth factor, and transforming growth factor-β modulated steady-state levels of Eck and B61 mRNA and regulated Eck activation as assessed by tyrosine phosphorylation. Functionally, stimulation of Eck by B61 resulted in increased proliferation, enhanced barrier function, and enhanced restitution of injured epithelial monolayers. These results suggest that the Eck-B61 interaction, a target of regulatory peptides, plays a role in intestinal epithelial cell development, migration, and barrier function, contributing to homeostasis and preservation of continuity of the epithelial barrier.
Morphometry and strain distribution in guinea pig duodenum with reference to the zero-stress state
Authors: Gregersen H. , Kassab G. , Pallencaoe E. , Lee C. , Chien S. , Skalak R. , Fung Y. C.
Published: December 2017

The aim of the present study is to determine the distribution of residual circumferential strains along the duodenum in anesthetized guinea pigs. A silicone elastomer was allowed to harden in the duodenal lumen under a pressure of 0.7 kPa. The duodenum was excised with the cast and photographed. The zero-stress state was obtained by cutting rings of duodenum radially. The geometric configuration at the zero-stress state is of fundamental importance, because it is the basic state with respect to which the physical stresses and strains are defined. A basic piece of information is the way the tangent vector rotates from one end of the circumference to the other. In the duodenum at zero-stress state, the total rotation of the tangent from one tip to the other is −500 to −850°, with the lowest absolute value in the proximal duodenum. In other words, the duodenum usually turns itself inside out on changing from a loaded state to the zero-stress state. The serosal circumference, the duodenal wall thickness, and the ratio of wall thickness to mucosal circumference decreased in the distal direction. In the pressurized state, the serosal Cauchy strain was tensile and increased in the distal direction; the mucosal Cauchy strain was compressive in the proximal half of the duodenum and tensile in the distal half. The large circumferential residual strains must be taken into account in a study of physiological problems in which the stresses and strains are important, e.g., the bolus transport function.
Responsiveness to growth factors in aortic vascular smooth muscle cells from rats with cirrhosis
Authors: Tazi Khalid A. , Trombino Concetta , Moreau Richard , Lebrec Didier
Published: December 2017

Hemodynamic changes in cirrhosis may be associated with alterations in aortic vascular smooth muscle cell (AVSMC) function. The present study compared the proliferative response to serum and growth factors in cirrhotic and control AVSMC. Serum from cirrhotic rats, cirrhotic cell lysates, and the conditioned medium of cultured cirrhotic AVSMC induced an increase in [3H]thymidine incorporation in control but not in cirrhotic AVSMC. Platelet-derived growth factor-β (PDGF-BB) induced a greater increase in [3H]thymidine incorporation in cirrhotic than in control cells. [3H]thymidine incorporation induced by cirrhotic conditioned medium was blocked by anti-PDGF antibody. Immunoblot studies showed that the anti-PDGF antibody recognized a 30-kDa protein in the conditioned medium of cirrhotic AVSMC culture, a protein corresponding to PDGF. Binding studies of PDGF-BB indicated a twofold increase in receptor density in cirrhotic AVSMC with no alteration in affinity for PDGF-BB. We conclude that an increased responsiveness of cirrhotic AVSMC to the PDGF could contribute to alterations in AVSMC and muscle cell tone that may play a role in the hemodynamic changes in cirrhosis.