Investigating Helicobacter pylori-related pyloric hypomotility: functional, histological, and molecular alterations.

Multiple theories have been proposed describing the pathogenic mechanisms of Helicobacter pylori (H. pylori)-associated gastric motility disorders. We assessed ex vivo pyloric activity in H. pylori-infected rats, and tried to explore the associated ghrelin hormone alteration and pyloric fibrogenesis. In addition, miR-1 was assessed in pyloric tissue samples, being recently accused of having a role in smooth muscle dysfunction. Ninety adult male Wistar albino rats were assigned into nine groups: 1) control group, 2) sterile broth (vehicle group), 3) amoxicillin control, 4) omeperazole control, 5) clarithromycin control, 6) triple therapy control, 7) H. pylori- group, 8) H. pylori-clarithromycin group, and 9) H. pylori-triple therapy group. Urease enzyme activity was applied as an indicator of H. pylori infection. Ex vivo pyloric contractility was evaluated. Serum ghrelin was assessed, and histological tissue evaluation was performed. Besides, pyloric muscle miR-1 expression was measured. The immunological epithelial to mesenchymal transition (EMT) markers; transforming growth factor ß (TGFß), α-smooth muscle actin (α-SMA), and E-cadherin-3 were also evaluated. By H. pylori infection, a significant (P < 0.001) reduced pyloric contractility index was recorded. The miR-1 expression was decreased (P < 0.001) in the H. pylori-infected group, associated with reduced serum ghrelin, elevated TGFß, and α-SMA levels and reduced E-cadherin levels. Decreased miR-1 and disturbed molecular pattern were improved by treatment. In conclusion, H. pylori infection was associated with reduced miR-1, epithelial to mesenchymal transition, and pyloric hypomotility. The miR-1 may be a target for further studies to assess its possible involvement in H. pylori-associated pyloric dysfunction, which might help in the management of human H. pylori manifestations and complications.NEW & NOTEWORTHY This work is investigating functional, histopathological, and molecular changes underlying Helicobacter pylori hypomotility and is correlating these with miR-1, whose disturbance is supposed to be involved in smooth muscle dysfunction and cell proliferation according to literature. Epithelial to mesenchymal transition and reduced ghrelin hormone may contribute to H. pylori infection-associated hypomotility. H. pylori infection was associated with reduced pyloric miR-1 expression. Targeting miR-1 could be valuable in the clinical management of pyloric hypofunction.

Evaluation of In Vivo Antiulcer Activity of Hydro-Methanol Extract and Solvent Fractions of the Stem Bark of Ficus thonningii (Moraceae) on Rodent Models.

INTRODUCTION: The stem bark of Ficus thonningii is used by Ethiopian traditional healers and the community for the treatment of peptic ulcer disease. Thus, the current study was aimed at evaluating the antiulcer effect of hydro-methanol extract and solvent fractions of F. thonningii. METHODS: The stem bark of F. thonningii was collected and shed dried. Then, the stem bark was extracted by 80% hydro-methanol solvents and dried. The part of the dried hydro-methanol extract was further fractionated with n-hexane, chloroform, and distilled water. Dose-dependent pylorus ligation, curative indomethacin-induced, and time-dependent ethanol-induced ulcer models were evaluated for the hydro-methanol extract and solvent fractions. Statistical analysis was done by using the Statistical Package for the Social Sciences (SPSS) version 24. The analyses were carried out using one-way analysis of variance (ANOVA), followed by Tukey's multiple comparison tests. The result was considered significant when p < 0.05. RESULTS: The extract of F. thonningii showed a significant (p < 0.001) reduction in total acidity at all the tested doses (100, 200, and 400 mg/kg). All the tested doses of the hydro-methanol extract significantly reduced the gastric volume as compared to the vehicle (NC) (p < 0.01). The gastric pH was significantly (p < 0.05) increased by 200 and 400 mg/kg. Similarly, 200 mg/kg and 400 mg/kg significantly (p < 0.05) lowered gastric ulceration as compared to the NC. The hydro-methanol extract and aqueous fractions of F. thonningii at 200 mg/kg showed significant (p < 0.05) reduction in the ulcer index on a repeated dose of the hydro-methanol and solvent fractions. Ulcer healing effect on indomethacin-induced ulcer was not significant (p > 0.05) for all tested doses of the hydro-methanol extract. CONCLUSION: The study demonstrated that the stem bark of F. thonningii has a potential antiulcer activity that might be due to antisecretory or cytoprotective effects.

Effects of Lactobacillus rhamnosus GG on early postoperative outcome after pylorus-preserving pancreatoduodenectomy: a randomized trial.

OBJECTIVE: Pancreatoduodenectomy (PPPD) remains one of the most complex surgical procedures with high complication rates. Infectious complications, postoperative ileus and delayed gastric emptying in the perioperative period have a significant impact on the recovery from the treatment. Probiotics (PB) are known to have a beneficial effect as supportive therapy in major abdominal surgery but the evidence in pancreatic surgery is still limited. The aim of the study was to assess the influence of postoperative administration of PB on the early outcomes after PPPD. PATIENTS AND METHODS: Forty patients undergoing pylorus-preserving PPPD were enrolled to prospective trial and randomized in two groups: A - control group (n=20) receiving standard nutrition and B - probiotic group (n=20) treated additionally with Lactobacillus rahmnosus GG (L. rhamnosus GG) in the postoperative period from the day of the surgery for 30 days. Gastrointestinal motility, infection complications, length of hospital stay, and mortality were compared in the perioperative period and during 2 follow-up (i.e., after 14 and 30 days). RESULTS: There were no significant differences in mortality and infectious complications between groups. The length of hospital stay was shorter in the probiotic group compared to control (10 days vs. 8, respectively). The positive effect of L. rhamnosus GG on gastrointestinal tract's motility was observed, including earlier recurrence of postoperative bowel movements (group B: after 3.75 days vs. group A: 2.15 days), passing gasses (group B after 4 days vs. group A 2.9 days) and the first postoperative stool (group B after 5.84 days vs. group A 3.85 days). L. rhamnosus GG improved the appetite in postoperative day 1, 3, 5, 7 and 30 days after the surgery. CONCLUSIONS: L. rhamnosus GG improves the function of the gastrointestinal tract after major pancreatic surgery and may reduce the length of hospital stay.

Role of Daucus carota in Enhancing Antiulcer Profile of Pantoprazole in Experimental Animals.

The carrot plant (Daucus carota) and its components are traditionally reported for the management of gastric ulcers. This study was performed to evaluate the role of carrot when administered concurrently with a conventional antiulcer treatment, pantoprazole, in alleviating gastric and duodenal ulcers in female experimental animals. The study involved standard animal models to determine the ulcer preventive effect using pylorus ligation, ethanol, and stress induced acute gastric ulcer models and duodenal ulcer models involving cysteamine. Acetic acid-induced chronic gastric ulcer and indomethacin-induced gastric ulcer models were used to evaluate the ulcer healing effect. Carrot fruit (500 mg/kg) and its co-administration with pantoprazole produced significant protection in an ethanol- and stress-induced acute gastric ulcer and cysteamine-induced duodenal ulcer. The healing of the acetic acid-induced chronic gastric ulcer was also augmented with this combination. Both total proteins and mucin contents were significantly increased in indomethacin-induced gastric ulcers. Similarly, in pylorus ligation, the pepsin content of gastric juice, total acidity, and free acidity were reduced. Overall, both ulcer preventive effects and ulcer healing properties of the pantoprazole were significantly enhanced in animals who received the co-administration of carrot fruit (500 mg/kg).

Cytoprotective and antisecretory properties of methanolic extract of Distemonanthus benthamianus (Caesalpiniaceae) stem bark on acute gastric ulcer in rats.

OBJECTIVES: In African traditional medicine, Distemonanthus benthamianus (Caesalpiniaceae) is used to treat many diseases including gastric ulcers. We evaluated in this study, the cytoprotective and antisecretory properties of the methanolic extract of the stem bark of this plant using different technics of gastric lesion induction. METHODS: Cytoprotective and antisecretory activity of the methanolic extract of D. benthamianus stem bark was evolved through six methods of gastric lesion induction in experimental Wistar male rats (150-200 g): (1) gastric lesions induced by HCl/ethanol, (2) gastric lesions induced by Indomethacin- HCl/ethanol, (3) gastric lesion induced by Indomethacin, (4) gastric lesions induced by Pylorus ligation, (5) gastric lesions induced by histamine-Pylorus ligation, (6) gastric lesions induced by carbachol-Pylorus ligation. Mucus and gastric mucosal ulceration were evaluated. pH, gastric volume, and acidity were quantified in all pylorus ligation induction technics. Nitric oxide (NO) level was determined in indomethacin induced gastric ulcers. RESULTS: At different doses (125, 250 and 500 mg/kg), extract reduced significantly the ulcer index. In all models used, that is 100.00% with HCl/ethanol; 100.00% with HCl/ethanol/indomethacin; 95.70% with Indomethacin; 74.79% with pylorus ligation, 95.94% histamine-Pylorus ligation, 99.54% carbachol-Pylorus ligation at the highest dose of 500 mg/kg. The lesion formation reduces in all the methods used followed by a significant increase of mucus production. The pylorus ligation technic revealed that the extract has an antisecretory activity. CONCLUSIONS: The methanolic extract of D. benthamianus stem bark has both cytoprotective and antisecretory effects. This extract exerts its antisecretory effect trough cholinergic and histaminergic pathways.

Endoscopic Botulinum toxin as a treatment for delayed gastric emptying following oesophagogastrectomy.

INTRODUCTION: The incidence of delayed gastric emptying (DGE) following oesophagogastrectomy with gastric conduit reconstruction is reported to be between 1.7% and 50%. This variation is due to differing practices of intraoperative pylorus drainage procedures, which increase the risk of postoperative biliary reflux and dumping syndrome, resulting in significant morbidity. The aim of our study was to establish rates of DGE in people undergoing oesophagogastrectomy without routine intraoperative drainage procedures, and to evaluate outcomes of postoperative endoscopically administered Botulinum toxin into the pylorus (EBP) for people with DGE resistant to systemic pharmacological treatment. METHODS: All patients undergoing oesophagogastrectomy between 1 January 2016 and 31 March 2018 at our unit were included. No intraoperative pyloric drainage procedures were performed, and DGE resistant to systemic pharmacotherapy was managed with EBP. RESULTS: Ninety-seven patients were included. Postoperatively, 29 patients (30%) were diagnosed with DGE resistant to pharmacotherapy. Of these, 16 (16.5%) were diagnosed within 30 days of surgery. The median pre-procedure nasogastric tube aspirate was 780ml; following EBP, this fell to 125ml (p<0.001). Median delay from surgery to EBP in this cohort was 13 days (IQR 7-16 days). Six patients required a second course of EBP, with 100% successful resolution of DGE before discharge. There were no procedural complications. CONCLUSIONS: This is the largest series of patients without routine intraoperative drainage procedures. Only 30% of patients developed DGE resistant to pharmacotherapy, which was managed safely with EBP in the postoperative period, thus minimising the risk of biliary reflux in people who would otherwise be at risk following prophylactic pylorus drainage procedures.

Effects of intraduodenal administration of lauric acid and L-tryptophan, alone and combined, on gut hormones, pyloric pressures, and energy intake in healthy men.

BACKGROUND: The fatty acid, lauric acid ('C12'), and the amino acid, L-tryptophan ('Trp'), modulate gastrointestinal functions including gut hormones and pyloric pressures, which are important for the regulation of energy intake, and both potently suppress energy intake. OBJECTIVE: We hypothesized that the intraduodenal administration of C12 and Trp, at loads that do not affect energy intake individually, when combined will reduce energy intake, which is associated with greater modulation of gut hormones and pyloric pressures. DESIGN: Sixteen healthy, lean males (age: 24 ± 1.5 y) received 90-min intraduodenal infusions of saline (control), C12 (0.3 kcal/min), Trp (0.1 kcal/min), or C12 + Trp (0.4 kcal/min), in a randomized, double-blind, cross-over study. Antropyloroduodenal pressures were measured continuously, and plasma cholecystokinin (CCK), ghrelin, and glucagon-like peptide-1 (GLP-1) concentrations, appetite perceptions, and gastrointestinal symptoms at 15-min intervals. Immediately after the infusions, energy intake from a standardized buffet meal was quantified. RESULTS: C12 + Trp markedly reduced energy intake (kcal; control: 1,232 ± 72, C12: 1,180 ± 82, Trp: 1,269 ± 73, C12 + Trp: 1,056 ± 106), stimulated plasma CCK (AUC(area under the curve)0-90 min, pmol/L*min; control: 21 ± 8; C12: 129 ± 15; Trp: 97 ± 16; C12 + Trp: 229 ± 22) and GLP-1 (AUC0-90 min, pmol/L*min; control: 102 ± 41; C12: 522 ± 102; Trp: 198 ± 63; C12 + Trp: 545 ± 138), and suppressed ghrelin (AUC0-90 min, pg/mL*min; control: -3,433 ± 2,647; C12: -11,825 ± 3,521; Trp: -8,417 ± 3,734; C12 + Trp: -18,188 ± 4,165) concentrations, but did not stimulate tonic, or phasic, pyloric pressures, compared with the control (all P < 0.05), or have adverse effects. C12 and Trp each stimulated CCK (P < 0.05), but to a lesser degree than C12 + Trp, and did not suppress energy intake or ghrelin. C12, but not Trp, stimulated GLP-1 (P < 0.05) and phasic pyloric pressures (P < 0.05), compared with the control. CONCLUSION: The combined intraduodenal administration of C12 and Trp, at loads that individually do not affect energy intake, substantially reduces energy intake, which is associated with a marked stimulation of CCK and suppression of ghrelin. The study was registered as a clinical trial at the Australian and New Zealand Clinical Trial Registry (www.anzctr.org.au,) as 12613000899741.

Pyloric distensibility measurement predicts symptomatic response to intrapyloric botulinum toxin injection.

BACKGROUND AND AIMS: Recent studies have reported that pyloric distensibility was altered in 30% to 50% of patients with gastroparesis, and this was correlated with gastric emptying and symptom severity. The aim of this study was to assess whether pyloric distensibility measurement was predictive of symptomatic response after intrapyloric botulinum toxin (BT) injection. METHODS: Pyloric distensibility was measured using the EndoFLIP system (Crospon, Galway, Ireland) before intrapyloric BT injection. Altered pyloric distensibility was defined as distensibility below 10 mm2/mm Hg. Total symptomatic score (TSS), dyspeptic symptoms, Gastrointestinal Quality of Life Index (GIQLI), and gastric emptying were investigated prospectively before and 3 months after BT injection. RESULTS: Nineteen of 35 patients had altered pyloric distensibility. In those patients, TSS decreased at 3 months from 13.5 to 10.5 (P < .01), whereas it remained unchanged in patients with normal pyloric distensibility (P = .7). Gastric fullness (from 3.5 to 2.5; P = .03) and bloating (from 3.0 to 2.0; P = .01) were the only symptoms that improved in patients with altered pyloric distensibility, whereas none of them was improved in patients with normal pyloric distensibility. GIQLI score increased from 59.5 to 76.5 in patients with altered pyloric distensibility (P = .02), whereas there was no statistical difference (P = .43) in patients with normal pyloric distensibility. In patients with altered pyloric distensibility, gastric emptying half time was 223 minutes before and 190 minutes 3 months after injection (P = .02), whereas it remained unchanged in patients with normal pyloric distensibility (P = .6). CONCLUSIONS: Pyloric distensibility measurement before intrapyloric BT injection predicted symptomatic and quality of life response 3 months after injection in patients with gastroparesis.

Neuromedin U is a gut peptide that alters oral glucose tolerance by delaying gastric emptying via direct contraction of the pylorus and vagal-dependent mechanisms.

The gut-brain peptide neuromedin U (NMU) decreases food intake and body weight and improves glucose tolerance. Here, we characterized NMU as an enteropeptide and determined how it impacts glucose excursion. NMU was expressed predominantly in the proximal small intestine, and its secretion was triggered by ingestion of a mixed meal. Although a single peripheral injection of NMU in C57BL/6NRj mice prevented the rise of glycemia upon an oral but not an intraperitoneal load of glucose, it unexpectedly prevented insulin secretion, only slightly improved peripheral insulin sensitivity, and barely reduced intestinal glucose absorption. Interestingly, peripheral administration of NMU abrogated gastric emptying. NMU receptors 1 and 2 were detected in pyloric muscles and NMU was able to directly induce pyloric contraction in a dose-dependent manner ex vivo in isometric chambers. Using a modified glucose tolerance test, we demonstrate that improvement of oral glucose tolerance by NMU was essentially, if not exclusively, because of its impact on gastric emptying. Part of this effect was abolished in vagotomized (VagoX) mice, suggesting implication of the vagus tone. Accordingly, peripheral injection of NMU was associated with increased number of c-FOS-positive neurons in the nucleus of the solitary tract, which was partly prevented in VagoX mice. Finally, NMU kept its ability to improve oral glucose tolerance in obese and diabetic murine models. Together, these data demonstrate that NMU is an enteropeptide that prevents gastric emptying directly by triggering pylorus contraction and indirectly through vagal afferent neurons. This blockade consequently reduces intestinal nutrient absorption and thereby results in an apparent improved tolerance to oral glucose challenge.-Jarry, A.-C., Merah, N., Cisse, F., Cayetanot, F., Fiamma, M.-N., Willemetz, A., Gueddouri, D., Barka, B., Valet, P., Guilmeau, S., Bado, A., Le Beyec, J., Bodineau, L., Le Gall, M. Neuromedin U is a gut peptide that alters oral glucose tolerance by delaying gastric emptying via direct contraction of the pylorus and vagal-dependent mechanisms.

Sepiapterin alleviates impaired gastric nNOS function in spontaneous diabetic female rodents through NRF2 mRNA turnover and miRNA biogenesis pathway.

An impaired nitrergic system and altered redox signaling contribute to gastric dysmotility in diabetics. Our earlier studies show that NF-E2-related factor 2 (NRF2) and phase II antioxidant enzymes play a vital role in gastric neuronal nitric oxide synthase (nNOS) function. This study aims to investigate whether supplementation of sepiapterin (SEP), a precursor for tetrahydrobiopterin (BH4) (a cofactor of NOS) via the salvage pathway, restores altered nitrergic systems and redox balance in spontaneous diabetic (DB) female rats. Twelve-week spontaneous DB and age-matched, non-DB rats, with and without dietary SEP (daily 20 mg/kg body wt for 10 days) treatment, were used in this study. Gastric antrum muscular tissues were excised to investigate the effects of SEP in nitrergic relaxation and the nNOS-nitric oxide (NO)-NRF2 pathway(s). Dietary SEP supplementation significantly ( P < 0.05) reverted diabetes-induced changes in nNOS dimerization and function; nitric oxide (NO) downstream signaling molecules; HSP-90, a key regulator of nNOSα activity and dimerization; miRNA-28 that targets NRF2 messenger RNA (mRNA), and levels of microRNA (miRNA) biogenesis pathway components, such as DGCR8 (DiGeorge Syndrome Critical Region Gene 8) and TRBP (HIV1-1 transactivating response RNA-binding protein). These findings emphasize the importance of the BH4 pathway in regulating gastric motility functions in DB animals by modulating nNOSα dimerization in association with changes in enteric NRF2 and NO downstream signaling. Our results also identify a new pathway, wherein SEP regulates NRF2 mRNA turnover by suppressing elevated miRNA-28, which could be related to alterations in miRNA biogenesis pathway components. NEW & NOTEWORTHY This study is the first to show a causal link between NF-E2-related factor 2 (NRF2) and neuronal nitric oxide synthase (nNOS) in gastric motility function. Our data demonstrate that critical regulators of the miRNA biosynthetic pathway are upregulated in the diabetic (DB) setting; these regulators were rescued by sepiapterin (SEP) treatment. Finally, we show that low dihydrofolate reductase expression may lead to impaired nNOS dimerization/function-reduced nitric oxide downstream signaling and elevate oxidative stress by suppressing the NRF2/phase II pathway through miRNA; SEP treatment restored all of the above in DB gastric muscular tissue. We suggest that tetrahydrobiopterin supplementation may be a useful therapy for patients with diabetes, as well as women with idiopathic gastroparesis.

Intraoperative Pyloric Interventions during Oesophagectomy: a Multicentre Study.

BACKGROUND: Denervation of the pylorus after oesophagectomy is considered the principal factor responsible for delayed gastric emptying. Several studies have attempted to delineate whether surgical or chemical management of the pylorus during oesophagectomy is of benefit, but with conflicting results. The aim of this multicentre study was to assess whether there was any difference in outcomes between different approaches to management of the pylorus. METHODS: A prospectively maintained database was used to identify patients who underwent oesophagectomy for malignancy. They were divided into separate cohorts based on the specific pyloric intervention: intra-pyloric botulinum toxin injection, pyloroplasty and no pyloric treatment. Main outcome parameters were naso-gastric tube duration and re-siting, endoscopic pyloric intervention after surgery both as in- and outpatient, length of hospital stay, in-hospital mortality and delayed gastric emptying symptoms at first clinic appointment. RESULTS: Ninety patients were included in this study, 30 in each group. The duration of post-operative naso-gastric tube placement demonstrated significance between the groups (p = 0.001), being longer for patients receiving botulinum treatment. The requirement for endoscopic pyloric treatment after surgery was again poorer for those receiving botulinum (p = 0.032 and 0.003 for inpatient and outpatient endoscopy, respectively). CONCLUSION: We did not find evidence of superiority of surgical treatment or botulinum toxin of the pylorus, as prophylactic treatment for potential delayed gastric emptying after oesophagectomy, compared to no treatment at all. Based on our findings, no treatment of the pylorus yielded the most favourable outcomes.

Gastroprotective activity of polysaccharide from Hericium erinaceus against ethanol-induced gastric mucosal lesion and pylorus ligation-induced gastric ulcer, and its antioxidant activities.

The gastroprotective activity of Hericium erinaceus polysaccharide was investigated in rats. The antioxidant activities were also evaluated. Pre-treatment of polysaccharide could reduce ethanol-induced gastric mucosal lesion and pylorus ligation-induced gastric ulcer. The polysaccharide exhibited scavenging activities of 1, 1-diphenyl-2-picryl-hydrozyl and hydroxyl radicals, and ferrous ion-chelating ability. In the pylorus ligation-induced model, gastric secretions (volume of gastric juice, gastric acid, pepsin and mucus) of ulcer rats administrated with polysaccharide were regulated. Levels of tumor necrosis factor-α and interleukins-1ß in serum, and myeloperoxidase activity of gastric tissue were reduced, while antioxidant status of gastric tissue was improved. Defensive factors (nitric oxide, prostaglandin E2, epidermal growth factor) in gastric tissue were increased. These results indicate that Hericium erinaceus polysaccharide possess gastroprotective activity, and the possible mechanisms are related to its regulations of gastric secretions, improvements of anti-inflammatory and antioxidant status, as well as increments of defensive factors releases.

Nonsteroidal anti-inflammatory drugs-induced failure of lower esophageal and pyloric sphincter and counteraction of sphincters failure with stable gatric pentadecapeptide BPC 157 in rats.

The sphincters failure is a part of NSAIDs-toxicity that can be accordingly counteracted. We used a safe stable gastric pentadecapeptide BPC 157 (GEPPPGKPADDAGLV, MW 1419), LD1 not achieved, since successful in inflammatory bowel disease trials, and counteracts esophagitis, sphincters failure, gastrointestinal ulcer and skin ulcer, external and internal fistulas in rats, and particularly counteracts all NSAIDs-lesions. We assessed lower esophageal sphincter and pyloric sphincter pressure (cmH2O) in rats treated with various NSAIDs regimens, at corresponding time points, known to produce stomach, small intestine lesions, hepatotoxicity and encephalopathy. Assessment was after diclofenac (12.5 mg/kg, 40 mg/kg intraperitoneal challenge), ibuprofen (400 mg/day/kg intraperitoneally for 4 weeks), paracetamol (5.0 g/kg intraperitoneal challenge), aspirin (400 mg/kg intraperitoneally or intragastrically), celecoxib (0.5 mg/kg, 1.0 mg/kg intraperitoneally). BPC 157 (10 µg/kg, 10 ng/kg) was given immediately after NSAIDs (intraperitoneally or intragastrically) or given in drinking water. Regularly, in all control NSAIDs fall of pressure occurred in both sphincters rapidly and then persisted. By contrast, in all NSAIDs-rats that received BPC 157, initial fall of pressure was minimized and pressure values restored to normal values. All tested NSAIDs decrease pressure in both sphincters, whilst BPC 157 counteracts their effects and restored both sphincters function.

The transient potassium outward current has different roles in modulating the pyloric and gastric mill rhythms in the stomatogastric ganglion.

The crustacean stomatogastric nervous system is a classic model for understanding the effects of modulating ionic currents and synapses at both the cell and network levels. The stomatogastric ganglion in this system contains two distinct central pattern generators: a slow gastric mill network that generates flexible rhythmic outputs (8-20 s) and is often silent, and a fast pyloric network that generates more consistent rhythmic outputs (0.5-2 s) and is always active in vitro. Different ionic conductances contribute to the properties of individual neurons and therefore to the overall dynamics of the pyloric and gastric mill networks. However, the contributions of ionic currents to different dynamics between the pyloric and gastric mill networks are not well understood. The goal of this study is to evaluate how changes in outward potassium current (I A) in the stomatogastric ganglion affect the dynamics of the pyloric and gastric mill rhythms by interfering with normal I A activity. We bath-applied the specific I A blocker 4-aminopyridine to reduce I A's effect in the stomatogastric ganglion in vitro and evaluated quantitatively the changes in both rhythms. We found that blocking I A in the stomatogastric ganglion alters the synchronization between pyloric neurons, and consistently activates the gastric mill rhythm in quiescent preparations.

Is Chemical Pyloroplasty Necessary for Minimally Invasive Esophagectomy?

BACKGROUND: Many centers use botulinum toxin for chemical pyloroplasty in minimally invasive esophagectomies as prophylaxis against delayed gastric emptying. No previous studies have compared botulinum toxin injection with no pyloric intervention for patients treated with a combined laparoscopic and thoracoscopic approach. The authors hypothesized that chemical pyloroplasty does not improve outcomes for these patients. METHODS: The study investigated patients undergoing minimally invasive esophagectomies from September 2009 to June 2015. Delayed gastric emptying was defined as inability to tolerate a soft diet by postoperative day 10, as corroborated by esophagram, upper endoscopy, or both. Data were compared using Student's t test, χ 2 analysis, and Mann-Whitney U test where appropriate. RESULTS: The study identified 71 patients treated with minimally invasive esophagectomy: 35 patients with chemical pyloroplasty treated from September 2009 to January 2014 and 36 patients without pyloric intervention from February 2014 to June 2015. The groups were statistically similar in age, gender distribution, T stage, percentage of patients receiving neoadjuvant therapy, body mass index, preoperative weight loss, preoperative serum albumin, and preoperative placement of feeding tubes (all p > 0.05). The overall incidence of delayed gastric emptying was low in both groups: 8.6% (3/35) of the patients with chemical pyloroplasty versus 5.6% (2/36) of the patients with no pyloric intervention (p = 0.62). The two groups also did not differ significantly in the development of aspiration pneumonia or the need for pyloric intervention. CONCLUSIONS: In a well-matched cohort study with a historical control group, use of botulinum toxin for chemical pyloroplasty in minimally invasive esophagectomies was not associated with improved outcomes related to the pylorus versus no pyloric intervention. Although preliminary, these data suggest that chemical pyloroplasty is not necessary in minimally invasive esophagectomy.

Nitric Oxide and Hydrogen Sulfide Interact When Modulating Gastric Physiological Functions in Rodents.

AIM: The objective was to evaluate the effects of nitric oxide (NO) and hydrogen sulfide (H2S) donors and possible interactions between these two systems in modulating gastric function. METHODS: Mice received saline, sodium nitroprusside (SNP), or sodium hydrosulfite (NaHS), and after 1 h, the animals were killed for immunofluorescence analysis of CSE or eNOS expressions, respectively. Other groups received saline, SNP, NaHS, Lawesson's reagent (H2S donor), PAG + SNP, L-NAME, L-NAME + NaHS, or L-NAME + Lawesson's reagent. Then, the gastric secretions (mucous and acid), gastric blood flow, gastric defense against ethanol, and gastric motility (gastric emptying and gastric contractility) were evaluated. RESULTS: SNP and NaHS increased the expression of CSE or eNOS, respectively. SNP or Lawesson's reagent did not alter gastric acid secretion but increased mucus production, and these effects reverted with PAG and L-NAME treatment, respectively. SNP or NaHS increased gastric blood flow and protected the gastric mucosa against ethanol injury, and these effects reverted with PAG and L-NAME treatments, respectively. SNP delayed gastric emptying when compared with saline, and PAG partially reversed this effect. NaHS accelerate gastric emptying, and L-NAME partially reversed this effect. SNP and NaHS alone induced gastric fundus and pylorus relaxation. However, pretreatment with PAG or L-NAME reversed these relaxant effects only in the pylorus but not in the gastric fundus. CONCLUSION: NO and H2S interact in gastric physiological functions, and this "cross-talk" is important in the control of mucus secretion, gastric blood flow, gastric mucosal defense, and gastric motility, but not in the control of basal gastric acid secretion.

Effect of endoscopic pyloric therapies for patients with nausea and vomiting and functional obstructive gastroparesis.

Gastroparesis (GP) is associated with loss of interstitial cells of Cajal (ICCs) and gastric dysrhythmias such as tachygastria. We hypothesized that a subset of patients with GP, normal 3cycles per minute (cpm) gastric myoelectrical activity (GMA), and normal upper endoscopy may respond to pyloric therapies. AIMS: To determine the effect of botulinum toxin A (btA) injection or balloon dilation (BD) of the pylorus on symptoms and body weight in patients with GP and 3cpm GMA. METHODS: Patients were identified who had GP, normal 3cpm GMA, and normal endoscopy that excluded mechanical obstruction of the pylorus. Electrogastrograms (EGG) with water load tests (WLT) were recorded to determine GMA. Gastric emptying was measured with 4h scintigraphy. Each patient underwent up to three pyloric treatments with btA or BD. RESULTS: Thirty-three patients (29 women) with an average age of 42years were studied. Seventy-nine percent had idiopathic GP and 21% had diabetic GP. The average percent meal retained at 4h was 42% and each EGG test showed normal 3cpm GMA. Nausea was the major symptom in 76% of patients. Complete or partial symptom response occurred in 75%, 72%, and 88% of patients after the first, second, or third endoscopic pyloric treatment, respectively. Overall, 78% of the 33 patients reported improvement in symptoms and average weight gain was 1.54lb from baseline to final treatment (p<0.04). CONCLUSION: Pyloric therapies appear to be effective treatments in symptomatic patients with GP and 3cpm GMA and controlled trials are warranted.

Inhibitory Effects of Botulinum Toxin Type A on Pyloric Cholinergic Muscle Contractility of Rat.

Botulinum toxin type A (BTX-A) selectively cleaves synaptosomal-associated protein of 25 kDa (SNAP-25) and results in inhibition of the fusion of synaptic vesicles containing neurotransmitters with the presynaptic membrane to undergo exocytosis and release. The aim of this study was to investigate whether BTX-A inhibited the pyloric smooth muscle contractility induced by acetylcholine (ACh) after BTX-A-mediated cleavage of SNAP-25 antagonized by toosendanin (TSN). Three groups of rat pyloric muscle strips were studied in vitro. All strips were allowed to equilibrate for 52 min under a basal loading tension of 1 g in Krebs solution and spontaneous contractile waves were recorded as their own controls before adding each drug. According to experimental protocols, 100 µM ACh, 1 µM atropine, 29.6 µM TSN and 10 U/ml BTX-A was added, respectively. BTX-A directly inhibited pyloric spontaneous contraction and ACh-induced contractile response. Addition of 10 U/ml BTX-A still inhibited pyloric smooth muscle contractility following incubation of TSN, while subsequent administration of 100 µM ACh had no effect. BTX-A inhibits pyloric smooth muscle contractility in our study suggesting BTX-A inhibits not only ACh release from cholinergic nerves but also muscarinic cholinergic muscular transmission.

The Inhibitory Effect of Botulinum Toxin Type A on Rat Pyloric Smooth Muscle Contractile Response to Substance P In Vitro.

A decrease in pyloric myoelectrical activity and pyloric substance P (SP) content following intrasphincteric injection of botulinum toxin type A (BTX-A) in free move rats have been demonstrated in our previous studies. The aim of the present study was to investigate the inhibitory effect of BTX-A on rat pyloric muscle contractile response to SP in vitro and the distributions of SP and neurokinin 1 receptor (NK1R) immunoreactive (IR) cells and fibers within pylorus. After treatment with atropine, BTX-A (10 U/mL), similar to [D-Arg¹, D-Phe5, D-Trp(7,9), Leu(11)]-SP (APTL-SP, 1 µmol/L) which is an NK1R antagonist, decreased electric field stimulation (EFS)-induced contractile tension and frequency, whereas, subsequent administration of APTL-SP did not act on contractility. Incubation with BTX-A at 4 and 10 U/mL for 4 h respectively decreased SP (1 µmol/L)-induced contractions by 26.64% ± 5.12% and 74.92% ± 3.62%. SP-IR fibers and NK1R-IR cells both located within pylorus including mucosa and circular muscle layer. However, fewer SP-fibers were observed in pylorus treated with BTX-A (10 U/mL). In conclusion, BTX-A inhibits SP release from enteric terminals in pylorus and EFS-induced contractile responses when muscarinic cholinergic receptors are blocked by atropine. In addition, BTX-A concentration- and time-dependently directly inhibits SP-induced pyloric smooth muscle contractility.