HCl-induced inflammatory mediators in cat esophageal mucosa and inflammatory mediators in esophageal circular muscle in an in vitro model of esophagitis

2006 ◽  
Vol 290 (6) ◽  
pp. G1307-G1317 ◽  
Author(s):  
Ling Cheng ◽  
Weibiao Cao ◽  
Claudio Fiocchi ◽  
Jose Behar ◽  
Piero Biancani ◽  
...  
Keyword(s):  
Inflammatory Mediators ◽  
Platelet Activating Factor ◽  
Circular Muscle ◽  
Muscle Layer ◽  
Normal Mucosa ◽  
Esophageal Mucosa ◽  
Mrna Levels ◽  
Physiol Gastrointest Liver ◽  
Krebs Buffer

Platelet-activating factor (PAF) and interleukin-6 (IL-6) are produced in the esophagus in response to HCl and affect ACh release, causing changes in esophageal motor function similar to esophagitis (Cheng L, Cao W, Fiocchi C, Behar J, Biancani P, and Harnett KM. Am J Physiol Gastrointest Liver Physiol 289: G418–G428, 2005). We therefore examined HCl-activated mechanisms for production of PAF and IL-6 in cat esophageal mucosa and circular muscle. A segment of normal mucosa was tied at both ends, forming a mucosal sac (Cheng L, Cao W, Fiocchi C, Behar J, Biancani P, and Harnett KM. Am J Physiol Gastrointest Liver Physiol 289: G860–G869, 2005) that was filled with acidic Krebs buffer (pH 5.8) or normal Krebs buffer (pH 7.0) as control and kept in oxygenated Krebs buffer for 3 h. The supernatant of the acidic sac (MS-HCl) abolished contraction of normal muscle strips in response to electric field stimulation. The inhibition was reversed by the PAF antagonist CV3988 and by IL-6 antibodies. PAF and IL-6 levels in MS-HCl and mucosa were significantly elevated over control. IL-6 levels in mucosa and supernatant were reduced by CV3988, suggesting that formation of IL-6 depends on PAF. PAF-receptor mRNA levels were not detected by RT-PCR in normal mucosa, but were significantly elevated after exposure to HCl, indicating that HCl causes production of PAF and expression of PAF receptors in esophageal mucosa and that PAF causes production of IL-6. PAF and IL-6, produced in the mucosa, are released to affect the circular muscle layer. In the circular muscle, PAF causes production of additional IL-6 that activates NADPH oxidase to induce production of H2O2. H2O2 causes formation of IL-1β that may induce production of PAF in the muscle, possibly closing a self-sustaining cycle of production of inflammatory mediators.

In vitro model of acute esophagitis in the cat

2005 ◽  
Vol 289 (5) ◽  
pp. G860-G869 ◽  
Author(s):  
Ling Cheng ◽  
Weibiao Cao ◽  
Claudio Fiocchi ◽  
Jose Behar ◽  
Piero Biancani ◽  
...  
Keyword(s):  
In Vitro Model ◽  
Circular Muscle ◽  
Muscle Layer ◽  
Normal Mucosa ◽  
Esophageal Mucosa ◽  
Acute Esophagitis ◽  
Vitro Model ◽  
Esophageal Contraction

We have shown that IL-1β and IL-6, possibly originating from the mucosa in response to injury, inhibit neurally mediated contraction of esophageal circular muscle but do not affect ACh-induced contraction, reproducing the effect of experimental esophagitis on esophageal contraction. To examine the interaction of mucosa and circular muscle in inflammation, we examined the effect of HCl on in vitro esophageal mucosa and circular muscle. Circular muscle strips, when directly exposed to HCl, contracted normally. However, when circular muscle strips were exposed to supernatants of mucosa incubated in HCl (2–3 h, pH 5.8), contraction decreased, and the inhibition was partially reversed by an IL-6 antibody. Supernatants from the mucosa of animals with in vivo-induced acute esophagitis (AE) similarly reduced contraction. IL-6 levels were higher in mucosal tissue from AE animals than in control mucosa and in AE mucosa supernatants than in normal mucosa supernatants. IL-6 levels increased significantly in normal mucosa and supernatants in response to HCl, suggesting increased production and release of IL-6 by the mucosa. IL-6 increased H2O2 levels in the circular muscle layer but not in mucosa. Exposure of the mucosa to HCl caused IL-1β to increase only in the mucosa and not in the supernatant. These data suggest that HCl-induced damage occurs first in the mucosa, leading to the production of IL-1β and IL-6 but not H2O2. IL-1β appears to remain in the mucosa. In contrast, IL-6 is produced and released by the mucosa, eventually resulting in the production of H2O2 by the circular muscle, with this affecting circular muscle contraction.

scholarly journals HCl-induced inflammatory mediators in esophageal mucosa increase migration and production of H2O2 by peripheral blood leukocytes

2010 ◽  
Vol 299 (3) ◽  
pp. G791-G798 ◽  
Author(s):  
Jie Ma ◽  
Annamaria Altomare ◽  
Suzanne de la Monte ◽  
Ming Tong ◽  
Florian Rieder ◽  
...  
Keyword(s):  
Inflammatory Mediators ◽  
Peripheral Blood ◽  
Platelet Activating Factor ◽  
Esophageal Mucosa ◽  
Leukocyte Activation ◽  
Peripheral Blood Leukocytes ◽  
Blood Leukocytes ◽  
Neurokinin 1 ◽  
Krebs Buffer ◽  
Cgrp Antagonist

Exposure of esophageal mucosa to hydrochloric acid (HCl) is a crucial factor in the pathogenesis of reflux disease. We examined supernatant of HCl-exposed rabbit mucosa for inflammatory mediators enhancing migration of leukocytes and production of H2O2 as an indicator of leukocyte activation. A tubular segment of rabbit esophageal mucosa was tied at both ends to form a sac, which was filled with HCl-acidified Krebs buffer at pH 5 (or plain Krebs buffer as control) and kept oxygenated at 37°C. The medium around the sac (supernatant) was collected after 3 h. Rabbit peripheral blood leukocytes (PBL) were isolated, and sac supernatant was used to investigate PBL migration and H2O2 production. HCl-exposed esophageal mucosa released substance P (SP), CGRP, platelet-activating factor (PAF), and IL-8 into the supernatant. PBL migration increased in response to IL-8 or to supernatant of the HCl-filled mucosal sac. Supernatant-induced PBL migration was inhibited by IL-8 antibodies and by antagonists for PAF (CV3988) or neurokinin 1 (i.e., SP), but not by a CGRP antagonist. Supernatant of the HCl-filled mucosal sac increased H2O2 release by PBL that was significantly reduced by CV3988 and by a SP antagonist but was not affected by IL-8 antibodies or by a CGRP antagonist. We conclude that IL-8, PAF, and SP are important inflammatory mediators released by esophageal mucosa in response to acid that promote PBL migration. In addition, PAF and SP induce production of H2O2 by PBL. These findings provide a direct link between acid exposure and recruitment and activation of immune cells in esophageal mucosa.

scholarly journals HCl-activated neural and epithelial vanilloid receptors (TRPV1) in cat esophageal mucosa

2009 ◽  
Vol 297 (1) ◽  
pp. G135-G143 ◽  
Author(s):  
Ling Cheng ◽  
Suzanne de la Monte ◽  
Jie Ma ◽  
Jie Hong ◽  
Ming Tong ◽  
...  
Keyword(s):  
Substance P ◽  
Epithelial Cells ◽  
Transient Receptor Potential ◽  
Platelet Activating Factor ◽  
Circular Muscle ◽  
Receptor Potential ◽  
Transient Receptor Potential Channel ◽  
Esophageal Mucosa ◽  
Transient Receptor ◽  
Krebs Buffer

To test whether transient receptor potential channel vanilloid subfamily member-1 (TRPV1) mediates acid-induced inflammation in the esophagus, a tubular segment of esophageal mucosa was tied at both ends, forming a sac. The sac was filled with 0.01 N HCl (or Krebs buffer for control) and kept in oxygenated Krebs buffer at 37°C. The medium around the sac (supernatant) was collected after 3 h. Supernatant of the HCl-filled sac abolished contraction of esophageal circular muscle strips in response to electric field stimulation. Contraction was similarly abolished by supernatant of mucosal sac filled with the TRPV1 agonist capsaicin (10−6 M). These effects were reversed by the selective TRPV1 antagonist 5′-iodoresiniferatoxin (IRTX) and by the platelet-activating factor (PAF) receptor antagonist CV9388. Substance P and CGRP levels in mucosa and in supernatant increased in response to HCl, and these increases were abolished by IRTX and by tetrodotoxin (TTX) but not affected by CV9388, indicating that substance P and CGRP are neurally released and PAF independent. In contrast, the increase in PAF was blocked by IRTX but not by TTX. Presence of TRPV1 receptor was confirmed by RT-PCR and by Western blot analysis in whole mucosa and in esophageal epithelial cells enzymatically isolated and sorted by flow cytometry or immunoprecipitated with cytokeratin antibodies. In epithelial cells PAF increased in response to HCl, and the increase was abolished by IRTX. We conclude that HCl-induced activation of TRPV1 receptors in esophageal mucosa causes release of substance P and CGRP from neurons and release of PAF from epithelial cells.

Production of IL-1β, hydrogen peroxide, and nitric oxide by colonic mucosa decreases sigmoid smooth muscle contractility in ulcerative colitis

2005 ◽  
Vol 289 (6) ◽  
pp. C1408-C1416 ◽  
Author(s):  
Weibiao Cao ◽  
Claudio Fiocchi ◽  
Victor E. Pricolo
Keyword(s):  
Nitric Oxide ◽  
Ulcerative Colitis ◽  
Circular Muscle ◽  
Muscle Cells ◽  
Muscle Layer ◽  
Normal Mucosa ◽  
Neurokinin A ◽  
Muscle Contractility ◽  
Smooth Muscle Contractility

We have previously shown that sigmoid circular muscle cells from patients with ulcerative colitis (UC) exhibit reduced contraction and Ca2+ signaling in response to the neurotransmitter neurokinin A (NKA) and that IL-1β and H2O2 may contribute to these reduced responses in UC. In addition, we have found that nitric oxide (NO) levels were significantly increased in UC circular muscle. To establish the site of origin for IL-1β, H2O2, and NO, we assembled an in vitro system in which normal or UC mucosa were sealed between two chambers filled with oxygenated Krebs solution. Because the mucosa consists of full-thickness mucosa and submucosa, it is expected that whatever is released into the undernatant from the submucosal side may diffuse to the circular muscle layer in the intact colon. Treatment of normal sigmoid circular muscle cells for 2 h with undernatants collected from the UC submucosal side (UCS) significantly decreased contraction induced by NKA and thapsigargin and the NKA- and caffeine-induced Ca2+ signal in Ca2+-free medium. In addition, UC mucosa released into the undernatant on its submucosal side significantly more H2O2, IL-1β, and NO than normal mucosa. The reduction in contraction and Ca2+ signal induced by UCS was partially reversed by pretreatment with an IL-1β antibody or with catalase. The NO scavenger hemoglobin partially prevented UCS-induced reduction in contraction and Ca2+ signaling in response to NKA but not the reduced response to thapsigargin or caffeine. Sodium nitroprusside inhibited NKA but not the caffeine-induced Ca2+ signal. We conclude that in UC the mucosa releases IL-1β, H2O2, and NO, which may contribute to the impaired Ca2+ release and altered sigmoid muscle contractility.

Circumferential, not longitudinal, colonic stretch increases synaptic input to mouse prevertebral ganglion neurons

2003 ◽  
Vol 285 (6) ◽  
pp. G1129-G1138 ◽  
Author(s):  
Steven M. Miller ◽  
J. H. Szurszewski
Keyword(s):  
Synaptic Input ◽  
Muscle Tension ◽  
Circular Muscle ◽  
Longitudinal Axis ◽  
Muscle Layer ◽  
Intraluminal Pressure ◽  
Colon Wall ◽  
Mesenteric Ganglion ◽  
Ganglion Neurons

The relationship between longitudinal and circular muscle tension in the mouse colon and mechanosensory excitatory synaptic input to neurons in the superior mesenteric ganglion (SMG) was investigated in vitro. Electrical activity was recorded intracellularly from SMG neurons, and muscle tension was simultaneously monitored in the longitudinal, circumferential, or both axes. Colonic intraluminal pressure and volume changes were also monitored simultaneously with muscle tension changes. The results showed that the frequency of fast excitatory postsynaptic potentials (fEPSPs) in SMG neurons increased when colonic muscle tension decreased, when the colon relaxed and refilled with fluid after contraction, and during receptive relaxation preceding spontaneous colonic contractions. In contrast, fEPSP frequency decreased when colonic muscle tension increased during spontaneous colonic contraction and emptying. Manual stretch of the colon wall to 10-15% beyond resting length in the circumferential axis of flat sheet preparations increased fEPSP frequency in SMG neurons, but stretch in the longitudinal axis to 15% beyond resting length in the same preparations did not. There was no increase in synaptic input when tubular colon segments were stretched in their long axes up to 20% beyond their resting length. The circumferential stretch-sensitive increase in the frequency of synaptic input to SMG neurons persisted when the colonic muscles were relaxed pharmacologically by nifedipine (2 μM) or nicardipine (3 μM). These results suggest that colonic mechanosensory afferent nerves projecting to the SMG function as length or stretch detectors in parallel to the circular muscle layer.

Potential Role for Interleukin-1 in the Pathophysiology of Ulcerative Colitis

1994 ◽  
Vol 86 (5) ◽  
pp. 619-626 ◽  
Author(s):  
T. D. Wardle ◽  
L. A. Turnberg
Keyword(s):  
Ulcerative Colitis ◽  
Prostaglandin E2 ◽  
Inflammatory Mediators ◽  
Colonic Mucosa ◽  
Short Circuit ◽  
Interleukin 1 ◽  
Platelet Activating Factor ◽  
Short Circuit Current ◽  
Normal Mucosa ◽  
Leukotriene C4

1. Biopsies of colonic mucosa from patients with ulcerative colitis liberated more interleukin-1β, prostaglandin E2, leukotriene C4 and platelet-activating factor into the medium in which they were cultured than biopsies from patients with irritable bowel syndrome and histologically normal mucosa. 2. Addition of interleukin-1 stimulated release of greater quantities of all these inflammatory mediators, including interleukin-1 itself, from inflamed and normal mucosa. 3. Blockade of cyclo-oxygenase with indomethacin or of lipoxygenase with ICI 207968 or of phospholipase A2 with mepacrine inhibited release of prostaglandin E2 or leukotriene C4 or both of these plus platelet-activating factor, respectively. 4. Interleukin-1 stimulated the short-circuit current across isolated rat colonic mucosa mounted in flux chambers in a dose-dependent manner (Km 2 × 10−11 mol/l). This stimulation was markedly inhibited by the removal of chloride from the bathing media. 5. Indomethacin or ICI 207968 inhibited the short-circuit current response to interleukin-1 and a combination of these antagonists produced a greater inhibition. Mepacrine caused an even greater inhibition whereas tetrodotoxin plus mepacrine inhibited the current completely. 6. These data indicate that interleukin-1, released in excess from inflamed colonic mucosa, stimulates the release of a range of inflammatory mediators as well as of more interleukin-1. It probably acts by stimulating phospholipase A2 in inflammatory cells, probably lymphocytes, and can do so in normal and inflamed mucosa. Since, in rat colonic mucosa it stimulated an electrical response in very low concentrations, it is feasible that it is involved in the chloride secretion, and hence the diarrhoea, which may occur in inflammatory reactions. Hence treatment with mepacrine seems a prospect worth pursuing.

Origin of Motion in the Human Ureter: Mechanics, Energetics and Kinetics of the Myosin Molecular Motors

2012 ◽  
Vol 79 (2) ◽  
pp. 123-129 ◽  
Author(s):  
Romina Vargiu ◽  
Anna Perinu ◽  
Antonello De Lisa ◽  
Frank Tintrup ◽  
Francesco Manca ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Molecular Motors ◽  
Circular Muscle ◽  
Muscle Layer ◽  
Shortening Velocity ◽  
Smooth Muscle Layer ◽  
Circular Smooth Muscle ◽  
Longitudinal Smooth Muscle ◽  
Human Ureter

Background Ureteral peristalsis is the result of coordinated mechanical motor performance of longitudinal and circular smooth muscle layer of the ureter wall. The main aim of this study was to characterize in smooth muscle of proximal segments of human ureter, the mechanical properties at level of muscle tissue and at level of myosin molecular motors. Methods Ureteral samples were collected from 15 patients, who underwent nephrectomy for renal cancer. Smooth muscle strips longitudinally and circularly oriented from proximal segments of human ureter were used for the in vitro experiments. Mechanical indices including the maximum unloaded shortening velocity (Vmax), and the maximum isometric tension (P0) normalized per cross-sectional area, were determined in vitro determined in electrically evoked contractions of longitudinal and circular smooth muscle strips. Myosin cross-bridge (CB) number per mm2 (Ψ) the elementary force per single CB (Ψ) and kinetic parameters were calculated in muscle strips, using Huxley's equations adapted to nonsarcomeric muscles. Results Longitudinal smooth muscle strips exhibited a significantly (p<0.05) faster Vmax (63%) and a higher P0 (40%), if compared to circular strips. Moreover, longitudinal muscle strips showed a significantly higher unitary force (Ψ) per CB. However, no significant differences were observed in CB number, the attachment (f1) and the detachment (g2) rate constants between longitudinal and circular muscle strips. Conclusions The main result obtained in the present work documents that the mechanical, energetic and unitary forces per CB of longitudinal layer of proximal ureter are better compared to the circular one; these preliminary findings suggested, unlike intestinal smooth muscle, a major role of longitudinal smooth muscle layer in the ureter peristalsis.

scholarly journals Paradoxical regulation of ChAT and nNOS expression in animal models of Crohn's colitis and ulcerative colitis

2013 ◽  
Vol 305 (4) ◽  
pp. G295-G302 ◽  
Author(s):  
John H. Winston ◽  
Qingjie Li ◽  
Sushil K. Sarna
Keyword(s):  
Ulcerative Colitis ◽  
Inflammatory Mediators ◽  
Distal Colon ◽  
Trinitrobenzene Sulfonic Acid ◽  
Mrna Levels ◽  
Functional Changes ◽  
Protein Gene Product ◽  
Dss Colitis ◽  
Nnos Expression

Morphological and functional changes in the enteric nervous system (ENS) have been reported in inflammatory bowel disease. We examined the effects of inflammation on the expression of choline acetyltransferase (ChAT) and nNOS in the muscularis externae of two models of colonic inflammation, trinitrobenzene sulfonic acid (TNBS)-induced colitis, which models Crohn's disease-like inflammation, and DSS-induced colitis, which models ulcerative Colitis-like inflammation. In TNBS colitis, we observed significant decline in ChAT, nNOS, and protein gene product (PGP) 9.5 protein and mRNA levels. In DSS colitis, ChAT and PGP9.5 were significantly upregulated while nNOS levels did not change. The nNOS dimer-to-monomer ratio decreased significantly in DSS- but not in TNBS-induced colitis. No differences were observed in the percentage of either ChAT (31 vs. 33%)- or nNOS (37 vs. 41%)-immunopositive neurons per ganglia or the mean number of neurons per ganglia (55 ± 5 vs. 59 ± 5, P > 0.05). Incubation of the distal colon muscularis externae in vitro with different types of inflammatory mediators showed that cytokines decreased ChAT and nNOS expression, whereas H2O2, a component of oxidative stress, increased their expression. NF-κB inhibitor MG-132 did not prevent the IL-1β-induced decline in either ChAT or nNOS expression. These findings showed that TNBS- and DSS-induced inflammation differentially regulates the expression of two critical proteins expressed in the colonic myenteric neurons. These differences are likely due to the exposure of the myenteric plexus neurons to different combinations of Th1-type inflammatory mediators and H2O2 in each model.

Longitudinal contractions in the duodenum: their fluid-mechanical function

1975 ◽  
Vol 228 (6) ◽  
pp. 1887-1892 ◽  
Author(s):  
J Melville ◽  
E Macagno ◽  
J Christensen
Keyword(s):  
Longitudinal Muscle ◽  
Circular Muscle ◽  
Muscle Layer ◽  
Slow Waves ◽  
Longitudinal Muscle Layer ◽  
Circular Muscle Layer ◽  
Model Flow ◽  
Displacement Wave ◽  
Marked Points

The hypothesis examined was that contractions of the longitudinal muscle layer occurin the duodenum which are independent of those of the circular muscle layer and that they induce flow of duodenal contents. A segment of opossum duodenum isolated in vitro was marked and photographed during periods of longitudinal muscle contraction, when the circular muscle layer appeared inactive. The prequency of longitudinal oscillation of the marked points was 20.5 cycles/min. The longitudinal displacement wave spread caudad with an average velocity of 3.27 cm/s. Frequency and velocity of electrical slow waves were determined in similiar duodenal segments. Slow-wave frquencywas 18.9 cycles/min. In a two-dimensional mechanical model, flow induced by simulatedlongitudinal muscle layer appear to be driven by the electrical slow waves of the duodenum. They are capable of inducing a pattern of flow in which ocntents flow betweenthe core and the periphery of the intestinal conduit.

Pylorectomy reduces the satiety action of cholecystokinin

1988 ◽  
Vol 255 (6) ◽  
pp. R1059-R1063 ◽  
Author(s):  
T. H. Moran ◽  
L. Shnayder ◽  
A. M. Hostetler ◽  
P. R. McHugh
Keyword(s):  
Binding Sites ◽  
Contractile Response ◽  
Behavioral Responses ◽  
Circular Muscle ◽  
Muscle Layer ◽  
Pyloric Sphincter ◽  
Cck Receptors ◽  
Physiological Assessment ◽  
Significant Attenuation

Rat gastric cholecystokinin (CCK) receptors are localized to the circular muscle layer of the pyloric sphincter, and a role for these receptors in the mediation of CCK satiety has been proposed. To directly assess the contribution of this receptor population in CCK satiety, the area of the pyloric sphincter containing these receptors was surgically removed, and the behavioral responses to CCK were compared pre- and postpylorectomy. The presence of CCK receptors in the gastroduodenal junction was assessed by either in vitro CCK receptor autoradiography or in vitro contractile response to CCK. The results depended on the time after pylorectomy during which testing occurred. Two to 3 wk after pylorectomy rats demonstrated a significant attenuation of CCK satiety such that while the response to 1 and 2 micrograms/kg was intact, any additional inhibition by 4 and 8 micrograms/kg was eliminated. At this time, no evidence of CCK receptors around the gastroduodenal junction was found. In contrast, 2-3 mo after pylorectomy, the normal dose-response inhibition to CCK was intact. Evidence for the presence of CCK binding sites at the gastroduodenal junction was found by both autoradiography and physiological assessment. These results indicate a role for pyloric CCK receptors in the mediation of CCK satiety.

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