Adenocarcinoma of oesophagus: what exactly is the size of the problem and who is at risk?

The incidence of oesophageal adenocarcinoma is increasing and the prognosis is poor. There is a strong predominance of white males, and heredity plays a minor role. The established risk factors are Barrett's oesophagus, gastro-oesophageal reflux, and obesity. Infection with Helicobacter pylori and use of non-steroidal anti-inflammatory drugs might reduce the risk. Medications that relax the lower oesophageal sphincter might contribute to increasing the risk. Among dietary factors, low intake of fruit, vegetables, and cereal fibres seem to increase the risk of oesophageal adenocarcinoma. The role of tobacco smoking is probably limited and alcohol consumption is not a risk factor. It is uncertain which factors cause the increasing incidence. Increasing prevalences of reflux and obesity, and decreasing prevalence of H pylori infection may contribute to this development; however, the sex distributions of these factors do not match the incidence trends well. Endoscopic surveillance for oesophageal adenocarcinoma among persons with reflux and obesity is discussed, but presently there is no evidence that strongly supports such a strategy.

Body mass index and chronic unexplained gastrointestinal symptoms: an adult endoscopic population based study

BACKGROUND

We aimed to determine whether obese subjects experience more gastro-oesophageal reflux (GORS) symptoms than normal subjects, and further to determine if this association was explained by oesophagitis or medications that lower oesophageal sphincter pressure.

METHODS

In a representative Swedish population, a random sample (n = 1001, mean age 53.5 years, 51% women) had upper endoscopy. GORS was defined as any bothersome heartburn or acid regurgitation.

RESULTS

The prevalence of obesity (body mass index > or =30) was 16%; oesophagitis was significantly more prevalent in obesity (26.5%) than in normal subjects (9.3%). There were associations between obesity and GORS (odds ratio (OR) 2.05 (95% confidence interval (CI) 1.39, 3.01)), epigastric pain (OR 1.63 (95% CI 1.05, 2.55)), irritable bowel symptoms (OR 1.58 (95% CI 1.05, 2.38)), any abdominal pain (OR 1.59 (95% CI 1.08, 2.35)), vomiting (OR 3.11 (95% CI 1.18, 8.20)), retching (OR 1.74 (95% CI 1.1.3, 2.67)), diarrhoea (OR 2.2 (95% CI 1.38, 3.46)), any stool urgency (OR 1.60 (95% CI 1.04, 2.47)), nocturnal urgency (OR 2.57 (95% CI 1.33, 4.98)), and incomplete rectal evacuation (OR 1.64 (95% CI 1.09, 2.47)), adjusting for age, sex, and education. When subjects with oesophagitis and peptic ulcer were excluded, only diarrhoea, incomplete evacuation, and vomiting were significantly associated with obesity. The association between GORS and obesity remained significant adjusting for medication use (OR 1.9 (95% CI 1.3, 3.0)).

CONCLUSIONS

GORS is associated with obesity; this appears to be explained by increased upper endoscopy findings in obesity.

Transient lower esophageal sphincter relaxations in dogs are inhibited by a metabotropic glutamate receptor 5 antagonist

Transient lower esophageal sphincter relaxation is the major mechanism for gastroesophageal reflux. The present study was initiated to investigate the potential effect of the metabotropic glutamate 5 (mGlu5) receptor antagonist, 2-methyl-6-(phenylethynyl)-pyridine (MPEP), on transient lower esophageal sphincter relaxations in the conscious dog. MPEP (1.4-8.7 micromol/kg i.v.) produced a dose-dependent inhibition of transient lower esophageal sphincter relaxations (59+/-11% inhibition at 8.7 micromol/kg). In addition, there was a reduction of the number of reflux episodes and an increase in latency time to the occurrence of the first transient lower esophageal sphincter relaxation. No effect was seen on basal lower esophageal sphincter pressure or on swallowing. It is concluded that the mGlu5 receptor antagonist MPEP potently inhibits transient lower esophageal sphincter relaxations and that the mGlu5 receptor is a potential target for treatment of gastroesophageal reflux disease.

Cannabinoids and the digestive tract

In the digestive tract there is evidence for the presence of high levels of endocannabinoids (anandamide and 2-arachidonoylglycerol) and enzymes involved in the synthesis and metabolism of endocannabinoids. Immunohistochemical studies have shown the presence of CB1 receptors on myenteric and submucosal nerve plexuses along the alimentary tract. Pharmacological studies have shown that activation of CB1 receptors produces relaxation of the lower oesophageal sphincter, inhibition of gastric motility and acid secretion, as well as intestinal motility and secretion. In general, CB1-induced inhibition of intestinal motility and secretion is due to reduced acetylcholine release from enteric nerves. Conversely, endocannabinoids stimulate intestinal primary sensory neurons via the vanilloid VR1 receptor, resulting in enteritis and enhanced motility. The endogenous cannabinoid system has been found to be involved in the physiological control of colonic motility and in some pathophysiological states, including paralytic ileus, intestinal inflammation and cholera toxin-induced diarrhoea. Cannabinoids also possess antiemetic effects mediated by activation of central and peripheral CB1 receptors. Pharmacological modulation of the endogenous cannabinoid system could provide a new therapeutic target for the treatment of a number of gastrointestinal diseases, including nausea and vomiting, gastric ulcers, secretory diarrhoea, paralytic ileus, inflammatory bowel disease, colon cancer and gastro-oesophageal reflux conditions.

Pharmacologic characterization of intrinsic mechanisms controlling tone and relaxation of porcine lower esophageal sphincter

The neurotransmitters mediating relaxation of lower esophageal sphincter (LES) were studied using circular LES strips from adult pigs in organ baths. LES relaxation by sodium nitroprusside (1 nM-3 microM), vasoactive intestinal peptide (VIP) and pituitary adenylate cyclase-activating peptide (PACAP; 1 nM-1 microM), ATP (10 microM-30 mM), and tricarbonyldichlororuthenum dimer (1 microM-1 mM) was unaffected by tetrodotoxin (1 microM) or l-N(G)-nitroarginine methyl ester (l-NAME; 100 microM). Calcitonin gene-related peptide (CGRP; 1 nM-1 microM) did not affect LES tone. ATP relaxation was blocked by 1 microM apamin and the P2Y(1) antagonist MRS 2179 (N6-methyl 2'-deoxyadenosine 3',5'-bisphosphate; 10 microM). Apamin inhibited PACAP relaxation. VIP and PACAP relaxation was blocked by 10 U/ml alpha-chymotrypsin. L-NAME (-62.52 +/- 13.13%) and 1H-[1,2,4]oxadiazole-[4,3-alpha]quinoxalin-1-one (ODQ; 10 microM, -67.67 +/- 6.80%) similarly inhibited electrical LES relaxation, and apamin blocked non-nitrergic relaxation. Nicotine relaxation (100 microM) was inhibited by L-NAME (-60.37 +/- 10.8%) and ODQ (-41.90 +/- 7.89%), and apamin also blocked non-nitrergic relaxation. Non-nitrergic and apamin-sensitive LES relaxation by electrical stimulation or nicotine was strongly inhibited by MRS 2179, slightly inhibited by alpha-chymotrypsin and the P2X(1,2,3) receptor antagonist NF 279 (8,8 cent-[carbonylbis(imino-4,1-phenylenecarbonylimino-4,1-phenylenecarbonylimino)]bis-1,3,5-naphthalenetrisulfonic acid hexasodium salt; 10 microM), and unaffected by tin protoporphyrin IX (100 microM). Porcine LES relaxation after stimulation of intrinsic inhibitory motor neurons is mediated by two main neuromuscular pathways: nitric oxide through guanylate cyclase signaling and apamin-insensitive mechanisms and by non-nitrergic apamin-sensitive neurotransmission mainly mediated by ATP, ADP, or a related purine acting on P2Y1 receptors and a minor contribution of purinergic P2X1,2,3 receptors and PACAP. Nitrergic and purinergic co-transmitters show parallel effects of similar magnitude without major interplay. Our study shows no role for CGRP and only a minor one for VIP and carbon monoxide in porcine LES relaxation.

Hydrogen peroxide reduces lower esophageal sphincter tone in human esophagitis

BACKGROUND & AIMS

We have previously used the normal lower esophageal sphincter (N-LES) of human organ donors to examine the physiologic signal transduction of lower esophageal sphincter (LES) circular muscle. Now, for the first time, we have obtained a human LES specimen with esophagitis (E-LES) and characterized its pathophysiologic mechanical and inflammatory profiles.

METHODS

E-LES was examined histologically, and its in vitro circular muscle contraction and production of inflammatory mediators were compared with those of N-LES.

RESULTS

E-LES exhibited scattered erosions and displayed inflammatory cells in the epithelial layer, basal zone hyperplasia, and elongation of lamina propria papillae, characteristic of chronic reflux esophagitis. E-LES muscle strips developed lower in vitro tone (0.78 g) than N-LES (3.3 +/- 0.2 g). E-LES tone was essentially restored to normal by the H2O2 scavenger catalase, suggesting that H2O2 was responsible for reduction of tone. NOX5 cDNA was higher and H2O2 levels were 4 times higher in E-LES circular muscle (0.85 nmol/mg protein) than in N-LES (0.19 +/- 0.05 nmol/mg protein). When N-LES smooth muscle was incubated in H2O2 (70 micromol/L, 2 hours), platelet activating factor (PAF), prostaglandin E2 (PGE2), and F2-isoprostane increased 2.5, 5.2, and 36 times, respectively. In E-LES, levels of PAF, PGE2, and F2-isoprostane were 4, 6, and 40 times, respectively, higher than in N-LES. PAF, PGE2, and F2 isoprostane produced dose-dependent reductions in tone of N-LES muscle strips.

CONCLUSIONS

We conclude that an excessive production of H2O2 triggers an increased production of PAF, PGE2, and F2-isoprostane, which are responsible for reducing LES tone in human esophagitis.

Esophagogastric junction outflow obstruction: Where are we now in diagnosis and management?

Esophagogastric junction outflow obstruction (EGJOO) is a major motility disorder based on the Chicago Classification of esophageal motility disorders. This entity involves a heterogenous group of underlying etiologies. The diagnosis is reached by performing high-resolution manometry. This reveals evidence of obstruction at the esophagogastric junction, manifested by an elevated integrated relaxation pressure (IRP) above a cutoff value (IRP threshold varies by the manometric technology and catheter used), with preserved peristalsis. Further tests like endoscopy, timed barium esophagram, and cross-sectional imaging can help further elucidate the underlying etiology and rule out mechanical causes. Treatment is tailored to the underlying cause. Similar to achalasia, treatment targeting lower esophageal sphincter disruption like pneumatic dilation, peroral endoscopic myotomy, and botulinum injection are used in patients with functional EGJOO and persistent symptoms.

(R)-(3-amino-2-fluoropropyl) phosphinic acid (AZD3355), a novel GABAB receptor agonist, inhibits transient lower esophageal sphincter relaxation through a peripheral mode of action

Gastroesophageal reflux disease (GERD) affects >10% of the Western population. Conventionally, GERD is treated by reducing gastric acid secretion, which is effective in most patients but inadequate in a significant minority. We describe a new therapeutic approach for GERD, based on inhibition of transient lower esophageal sphincter relaxation (TLESR) with a proposed peripherally acting GABA(B) receptor agonist, (R)-(3-amino-2-fluoropropyl)phosphinic acid (AZD3355). AZD3355 potently stimulated recombinant human GABA(B) receptors and inhibited TLESR in dogs, with a biphasic dose-response curve. In mice, AZD3355 produced considerably less central side effects than the prototypical GABA(B) receptor agonist baclofen but evoked hypothermia at very high doses (blocked by a GABA(B) receptor antagonist and absent in GABA(B)-/- mice). AZD3355 and baclofen differed markedly in their distribution in rat brain; AZD3355, but not baclofen, was concentrated in circumventricular organs as a result of active uptake (shown by avid intracellular sequestration) and related to binding of AZD3355 to native GABA transporters in rat cerebrocortical membranes. AZD3355 was also shown to be transported by all four recombinant human GABA transporters. AR-H061719 [(R/S)-(3-amino-2-fluoropropyl)phosphinic acid], (the racemate of AZD3355) inhibited the response of ferret mechanoreceptors to gastric distension, further supporting its peripheral site of action on TLESR. In summary, AZD3355 probably inhibits TLESR through stimulation of peripheral GABA(B) receptors and may offer a potential new approach to treatment of GERD.

Barrett's esophagus and medications that relax the lower esophageal sphincter

OBJECTIVES

Medications that may increase gastroesophageal reflux could be risk factors for esophageal adenocarcinoma; however, epidemiologic studies present conflicting results. We evaluated patients with a high-risk condition, Barrett's esophagus, to identify risk factors that may act early in the carcinogenic process.

METHODS

We conducted a nested case-control study within a large integrated health-services organization. Electronic databases were used to identify incident diagnoses of Barrett's esophagus (cases); two controls were matched to each case. Electronic databases provided information on the use of medications that may induce reflux (nitrates, calcium channel blockers, xanthines, benzodiazepines, and beta agonists) and potential confounders. A supplemental mailed questionnaire evaluated additional potential confounders.

RESULTS

We identified 421 cases and selected 842 controls. The association between any medication use and a Barrett's esophagus diagnosis was modified by age; an increased risk was observed only among subjects <70 yr of age (adjusted odds ratio [OR] = 2.6; 95% confidence interval [CI] 1.5-4.6). A Barrett's esophagus diagnosis was associated with asthma medication use (OR 5.8; 95% CI 2.2, 14.9), but not with the other medications studied. Subgroup analyses suggested that medication use was not independently associated with reflux symptoms and that adjustment for asthma symptoms substantially reduced the association between medication use and a Barrett's esophagus diagnosis.

CONCLUSION

The use of medications that may induce reflux was associated with a Barrett's esophagus diagnosis among younger persons. This association was only observed with asthma medications; the analyses suggested the possibility of confounding by indication, whereby reflux may cause both asthma and Barrett's esophagus.

The effects of cricoid pressure, remifentanil, and propofol on esophageal motility and the lower esophageal sphincter

Cricoid pressure is the gold standard during the induction of anesthesia when there is a risk of aspiration of gastric contents. However, the effect of cricoid pressure during the different steps of complete anesthesia induction has not been studied. The purpose of this study was to investigate the effects of cricoid pressure, remifentanil, and propofol on lower esophageal sphincter (LES) and esophageal motility. We recorded LES pressure (LESP) and calculated barrier pressure ([BrP] = LESP - gastric pressure) in 10 healthy volunteers using a Dent sleeve device. There was a significant decrease in LESP and BrP when a cricoid pressure of 30 N was performed in the awake volunteers (P < 0.05). However, this effect was not seen during the infusion of remifentanil 0.2 microg . kg(-1) . min(-1). Remifentanil per se or together with a bolus dose of propofol 1 mg/kg IV did not induce any statistical change in LESP or BrP. Remifentanil abolished spontaneous esophageal motility and completely eliminated the experience of discomfort induced by cricoid pressure. In conclusion, cricoid pressure of 30 N induced a decrease of LESP and BrP in awake volunteers. These effects were not seen during the remifentanil infusion. This shows the importance of when to apply cricoid pressure during rapid-sequence induction.

Injection of botulinum toxin before pneumatic dilatation in achalasia treatment: a randomized-controlled trial

BACKGROUND

Pneumatic dilatation is the first line therapy in achalasia, but half of patients relapse within 5 years of therapy and require further dilatations.

AIM

To assess whether botulinum toxin injection before pneumatic dilatation is superior to pneumatic dilatation alone in achalasia patients.

METHODS

Newly diagnosed achalasia patients were randomly assigned to receive botulinum toxin 1 month before pneumatic dilatation (botulinum toxin-pneumatic dilatation group: 27 patients with median age of 38) or to undergo pneumatic dilatation alone (pneumatic dilatation group: 27 patients with median age of 30). Response to therapy was assessed by clinical and objective methods at various intervals.

RESULTS

One-year remission rate of patients in botulinum toxin-pneumatic dilatation group was 77% compared with 62% in pneumatic dilatation group (P = 0.1). In pneumatic dilatation group, the oesophageal barium volume significantly (P < 0.001) decreased at 1 month, but this reduction did not persist over 1-year follow-up. Botulinum toxin-pneumatic dilatation group showed a significant (P < 0.001) reduction in barium volume at the various times intervals post-treatment. In the botulinum toxin-pneumatic dilatation group, 10/11 (91%) patients over 40 were in remission at 1 year, comparing with only five of nine (55%) cases in pneumatic dilatation group (P = 0.07).

CONCLUSION

Injection of botulinum toxin before pneumatic dilatation does not significantly enhance the efficacy of pneumatic dilatation.

Effects and mechanisms of electroacupuncture at PC6 on frequency of transient lower esophageal sphincter relaxation in cats

AIM: To investigate the effects of electroacupuncture (EA) at neiguan (PC6) on gastric distention-induced transient lower esophageal sphincter relaxations (TLESRs) and discuss the mechanisms of this treatment.

METHODS: ProtocolI: Twelve healthy cats underwent gastric distention for 60 min on the first day. Electrical acupoint stimulation was applied at the neiguan or a sham point on the hip in randomized order before gastric distention, on the third day and fifth day. Those cats that underwent EA at neiguan on the fifth day were named “Neiguan Group” and the cats that underwent EA at a sham acupoint on the fifth day were named “Sham Group” (control group). During the experiment the frequency of TLESRs and lower esophageal sphincter (LES) pressure were observed by a perfused sleeve assembly. Plasma levels of gastrin (GAS) and motilin (MTL) were determined by radioimmunoassay. Nitrite/nitrate concentration in plasma and tissues were measured by Griess reagent. The nuclei in the brain stem were observed by immunohistochemistry method of c-Fos and NADPH-d dyeing. Protocol II: Thirty six healthy cats were divided into 6 groups randomly. We gave saline (2 mL iv. control group), phaclofen (5 mg/kg iv. GABA-B antagonist), cholecystokinin octapeptide (CCK-8) (1 μg/kg per hour iv.), L-Arginine (200 mg/kg iv.), naloxone (2.5 μmol/kg iv.) and tacrine (5.6 mg/kg ip. cholinesterase inhibitor) respectively before EA at Neiguan and gastric distention. And the frequencies of TLESRs in experimental groups were compared with the control group.

RESULTS: ProtocolI: Not only the frequency of gastric distention-induced TLESR in 60 min but also the rate of common cavity during TLESRs were significantly decreased by EA at neiguan compared to that of sham acupoint stimulation. C-Fos immunoreactivity and NOS reactivity in the solitarius (NTS) and dorsal motor nucleus of the vagus (DMV) were significantly decreased by EA at neiguan compared to that of the sham group. However, the positive nuclei of C-Fos and NOS in reticular formation of the medulla (RFM) were increased by EA at neiguan. Protocol II: The inhibited effect of EA at neiguan on TLESR’s frequency was completely restored by pretreatment with CCK (23.5/h vs 4.5/h, P < 0.05), L-arginine (17.5/h vs 4.5/h, P < 0.05) and naloxone(12/h vs 4.5/h, P < 0.05). On the contrary, phaclofen (6/h vs 4.5/h, P > 0.05) and tacrine (9.5/h vs 4.5/h, P > 0.05) did not influence it.

CONCLUSION: Electric acupoint stimulation at Neiguan significantly inhibits the frequency of TLESR and the rate of common cavity during TLESR in cats. This effect appears to act on the brain stem, and may be mediated through nitric oxide (NO), CCK-A receptor and mu-opioid receptors. But the GABAB receptor and acetylcholine may not be involved in it.

Non-steroidal anti-inflammatory drugs, lower oesophageal sphincter-relaxing drugs and oesophageal cancer. A case-control study

BACKGROUND AND AIMS

The incidence of oesophageal cancer has doubled in the last three decades. Non-steroidal anti-inflammatory drugs (NSAIDs) may be protective, whilst bronchodilators and calcium channel blockers that relax the lower oesophageal sphincter (LOS) may increase gastro-oesophageal reflux and the risk of oesophageal adenocarcinoma. We conducted a case-control study to examine the association between the use of NSAIDs and drugs which relax the LOS and the risk of oesophageal cancer.

METHODS

In Norfolk, 411 patients with a primary neoplasm of the oesophagus or cardia were matched with 1,644 controls with non-melanotic skin lesions. Data on the use of NSAIDs, bronchodilators and calcium channel blockers was collected.

RESULTS

Intake of NSAIDs was less in cases of oesophageal cancer as compared to the control group. The odds ratios (OR) and 95% confidence intervals (CI) for different NSAIDs were as follows: aspirin 0.35 (0.24-0.51); other NSAIDs 0.25 (0.16-0.40), and Cox-2 inhibitors 0.46 (0.20-0.94). LOS-relaxing drugs were consumed more frequently in cases of oesophageal cancer as compared to the controls. The OR for LOS-relaxing drugs was: inhaled bronchodilators 3.2 (95% CI 2.2-4.7); theophylline 1.9 (95% CI 1.3-5.1), and calcium channel blockers 2.4 (95% CI 1.2-5.0).

CONCLUSION

Within the limitations of a case-control study using patients with non-melanotic skin lesions as controls, our results are consistent with the hypothesis that oesophageal cancer has a negative association with NSAID use, and a positive association with drugs that relax the LOS.

Effects of mosapride on esophageal functions and gastroesophageal reflux

BACKGROUND AND AIM

A substantial number of patients with gastroesophageal reflux disease show symptomatic resistance to high-dose proton pump inhibitors. In those cases, prokinetics are possible candidates for treatment. The aim of the present study was to determine whether mosapride, a prokinetic agent, stimulates esophageal functions, and prevents acidic and non-acidic gastroesophageal reflux.

METHODS

Normal volunteers (nine and 13 for two experiments, respectively) were enrolled. Salivary secretion, esophageal peristaltic contractions, and resting lower esophageal sphincter pressure with and without mosapride administration were recorded using a cross-over protocol. Post-prandial acidic and non-acidic reflux levels were also recorded.

RESULTS

Mosapride at a standard dose of 15 mg/day did not stimulate salivary secretion or any esophageal motor functions. It also failed to prevent acidic and non-acidic post-prandial gastroesophageal reflux.

CONCLUSIONS

Mosapride at 15 mg/day, a standard dose in Japan, did not change the esophageal motility and salivary secretion in healthy volunteers. Future study on a larger number of individuals with higher dose of mosapride is worthwhile.

Effect of an acute intraluminal administration of capsaicin on oesophageal motor pattern in GORD patients with ineffective oesophageal motility

Ineffective oesophageal motility (IOM) is a functional disorder affecting about 50% of gastro-oesophageal reflux disease (GORD) patients. This disease in a severe form limits the clearing ability of the oesophagus and is considered one of the predictive factors for poorer GORD resolution. Capsaicin, the active compound of red pepper, exerts a prokinetic effect on oesophageal motility in healthy subjects by increasing the amplitude of body waves, even if no evidence exists on its possible role in situations of reduced motility. The aim of the study was to evaluate the effect of an acute administration of capsaicin on the oesophageal motor pattern in a group of GORD patients affected by severe IOM. Twelve GORD patients with severe IOM received an intra-oesophageal administration of 2 mL of a red pepper-olive oil mixture and 2 mL of olive oil alone serving as a control during a stationary manometry. The motor patterns of the oesophageal body and lower oesophageal sphincter (LOS) were analysed at baseline and after the infusion of the two stimuli. The administration of capsaicin induced a significant improvement in oesophageal body contractility when compared with baseline. The velocity of propagation of waves and the LOS basal tone remained unchanged. The motor pattern was unaltered by the administration of olive oil alone. An acute administration of capsaicin seems to improve the motor performance of the oesophageal body in patients with ineffective motility. Whether this could represent the basis for further therapeutic approaches of GORD patients needs further study.

Esophagogastric anastomosis in rats: Improved healing by BPC 157 and L-arginine, aggravated by L-NAME

AIM

To cure typically life-threatening esophagogastric anastomosis in rats, lacking anastomosis healing and sphincter function rescue, in particular.

METHODS

Because we assume esophagogastric fistulas represent a particular NO-system disability, we attempt to identify the benefits of anti-ulcer stable gastric pentadecapeptide BPC 157, which was in trials for ulcerative colitis and currently for multiple sclerosis, in rats with esophagocutaneous fistulas. Previously, BPC 157 therapies have promoted the healing of intestinal anastomosis and fistulas, and esophagitis and gastric lesions, along with rescued sphincter function. Additionally, BPC 157 particularly interacts with the NO-system. In the 4 d after esophagogastric anastomosis creation, rats received medication (/kg intraperitoneally once daily: BPC 157 (10 μg, 10 ng), L-NAME (5 mg), or L-arginine (100 mg) alone and/or combined or BPC 157 (10 μg, 10 ng) in drinking water). For rats underwent esophagogastric anastomosis, daily assessment included progressive stomach damage (sum of the longest diameters, mm), esophagitis (scored 0-5), weak anastomosis (mL H₂O before leak), low pressure in esophagus at anastomosis and in the pyloric sphincter (cm H₂O), progressive weight loss (g) and mortality. Immediate effect assessed blood vessels disappearance (scored 0-5) at the stomach surface immediately after anastomosis creation.

RESULTS

BPC 157 (all regimens) fully counteracted the perilous disease course from the very beginning (i.e., with the BPC 157 bath, blood vessels remained present at the gastric surface after anastomosis creation) and eliminated mortality. Additionally, BPC 157 treatment in combination with L-NAME nullified any effect of L-NAME that otherwise intensified the regular course. Consistently, with worsening (with L-NAME administration) and amelioration (with L-arginine), either L-arginine amelioration prevails (attenuated esophageal and gastric lesions) or they counteract each other (L-NAME + L-arginine); with the addition of BPC 157 (L-NAME + L-arginine + BPC 157), there was a marked beneficial effect. BPC 157 treatment for esophagogastric anastomosis, along with NOS-blocker L-NAME and/or NOS substrate L-arginine, demonstrated an innate NO-system disability (as observed with L-arginine effectiveness). BPC 157 distinctively affected corresponding events: worsening (obtained with L-NAME administration that was counteracted); or amelioration (L-arginine + BPC 157-rats correspond to BPC 157-rats).

CONCLUSION

Innate NO-system disability for esophagogastric anastomoses, including L-NAME-worsening, suggests that these effects could be corrected by L-arginine and almost completely eliminated by BPC 157 therapy.

Feline lower esophageal sphincter sling and circular muscles have different functional inhibitory neuronal responses

The lower esophageal sphincter (LES) has a circular muscle component exhibiting spontaneous tone that is relaxed by nitric oxide (NO) and a low-tone sling muscle that contracts vigorously to cholinergic stimulation but with little or no evidence of NO responsiveness. This study dissected the responses of the sling muscle to nitrergic innervation in relationship to its cholinergic innervation and circular muscle responses. Motor responses were induced by electrical field stimulation (EFS; 1-30 Hz) of muscle strips from sling and circular regions of the feline LES in the presence of cholinergic receptor inhibition (atropine) or NO synthase inhibition [NG-nitro-L-arginine (L-NNA)+/-atropine]. This study showed the following. First, sling muscle developed less intrinsic resting tone compared with circular muscle. Second, with EFS, sling muscle contracted (most at <or=10 Hz), whereas circular muscle relaxed >50% by 5 Hz. Third, on neural blockade with atropine or L-NNA+/-atropine, 1) sling muscle, although predominantly influenced by excitatory cholinergic stimulation, had a small neural NO-mediated inhibition, with no significant non-NO-mediated inhibition and 2) circular muscle, although little affected by cholinergic influence, underwent relaxation predominantly by neural release of NO and some non-NO inhibitory influence (at higher EFS frequency). Fourth, the sling, precontracted with bethanecol, could relax with NO and some non-NO inhibition. Finally, the tension range of both muscles is similar. In conclusion, sling muscle has limited NO-mediated inhibition to potentially augment or replace sling relaxation effected by switching off its cholinergic excitation. Differences within the LES sling and circular muscles could provide new directions for therapy of LES disorders.

Protease-activated receptor-1 (PAR1) and PAR2 but not PAR4 mediate relaxations in lower esophageal sphincter

Protease-activated receptor-1 (PAR1), PAR2 and PAR4 activation can alter the gastrointestinal motility. To investigate effects mediated by PARs in the lower esophageal sphincter, we measured contraction or relaxation of transverse strips from the guinea-pig lower esophageal sphincter caused by PAR1 (TFLLR-NH2 and SFLLRN-NH2), PAR2 (SLIGKV-NH2 and SLIGRL-NH2) and PAR4 peptide agonists (GYPGKF-NH2, GYPGQV-NH2 and AYPGKF-NH2) as well as PAR protease activators (thrombin and trypsin). In resting lower esophageal sphincter strips, TFLLR-NH2 and SFLLRN-NH2 caused moderate concentration-dependent relaxation whereas thrombin did not cause any relaxation or contraction. Furthermore, in carbachol-contracted strips, TFLLR-NH2 and SFLLRN-NH2 caused marked whereas thrombin caused mild concentration-dependent relaxation. These indicate the existence of PAR1 mediating relaxation. Similarly, in resting lower esophageal sphincter strips, trypsin caused moderate concentration-dependent relaxation whereas SLIGRL-NH2 and SLIGKV-NH2 did not cause any relaxation or contraction. In addition, in carbachol-contracted strips, trypsin caused marked whereas SLIGRL-NH2 and SLIGKV-NH2 caused mild concentration-dependent relaxation. These indicate the existence of PAR2 mediating relaxation. The relaxant response of thrombin, TFLLR-NH2, trypsin and SLIGKV-NH2 was insensitive to atropine or tetrodotoxin, suggesting a direct effect. The relaxant response of trypsin was not affected by apamin, charybdotoxin, indomethacin and capsaicin but was attenuated by NG-nitro-L-arginine methyl ester, indicating involvement of NO. FSLLR-NH2, a PAR1 control peptide, and VKGILS-NH2, a PAR2 control peptide, as well as all three PAR4 peptide agonists, GYPGKF-NH2, GYPGQV-NH2 and AYPGKF-NH2, did not cause any relaxation or contraction. Taken together, these results demonstrate that PAR1 and PAR2 but not PAR4 mediate relaxations in the guinea-pig lower esophageal sphincter.

Effect of caffeine on lower esophageal sphincter pressure in Thai healthy volunteers

Caffeine affects many aspects of body function including the gastrointestinal system. A single-blinded experimental study was performed to evaluate the effect of caffeine on lower esophageal sphincter (LES) and esophageal peristaltic contractions in healthy Thai adults. The volunteers were six men and six women aged 19-31 years. Subjects drank 100 mL of water. Five wet swallows were performed 30 min after the drink. The basal LES pressure was continuously measured using esophageal manometric technique. They then consumed another 100 mL of water containing caffeine at the dose of 3.5 mg/kg body weight. The swallows and basal LES pressure monitoring were repeated. The results showed no change in basal LES pressure after a water drink while caffeine consumption significantly lowered the pressure at 10, 15, 20 and 25 min. The mean amplitude of contractions and peristaltic velocity were decreased at the distal esophagus at 3 and 8 cm above LES. The mean duration of contraction was decreased at the distal part but increased at the more proximal esophagus. The heart rate, systolic and diastolic blood pressures were increased significantly at 10-20 min after caffeine ingestion. This study indicated that caffeine 3.5 mg/kg affected esophageal function, resulting in a decrease in basal LES pressure and distal esophageal contraction, which is known to promote the reflux of gastric contents up into the esophagus.

Etiology and risk factors for oesophageal adenocarcinoma: possibilities for chemoprophylaxis?

The rapid increase in the incidence of oesophageal adenocarcinoma, particularly among white males, seems to be a true increase occurring in many parts of the industrialised world during the last few decades. Some main risk factors have been established: i.e. Barrett's oesophagus, gastrooesophageal reflux, high body mass, male sex, tobacco smoking, and high dietary intake of fruit and vegetables. Several other potential risk factors have been studied for which the evidence is less clear, including medications that relax the lower oesophageal sphincter or diets high in fat or low in nutrients from plant foods. Other factors have been found to be possibly inversely linked with the risk of oesophageal adenocarcinoma, including infection with Helicobacter pylori and anti-inflammatory drugs (such as aspirin and other non-steroidal anti-inflammatory drugs, including cyclo-oxygenase inhibitors). The methodological problem of 'confounding by indication' makes it difficult to interpret the results of anti-inflammatory drugs, and currently such medication cannot be recommended for the prevention of oesophageal adenocarcinoma. Similarly, since there is no strong evidence of a preventive effect of medical or surgical antireflux therapy with regard to risk of oesophageal adenocarcinoma, such therapy cannot be recommended in the prevention of this cancer. Although some of the known risk factors might contribute to the increasing incidence of oesophageal adenocarcinoma, the explanation that can entirely explain this striking trend remains to be identified. Oesophageal adenocarcinoma is a highly deadly cancer, but the overall prognosis and the prognosis after oesophageal cancer surgery has improved during recent years.

Tricyclic antidepressants and the risk of reflux esophagitis

OBJECTIVE

Incompetence of the lower esophageal sphincter (LES) is a key factor in the pathogenesis of gastroesophageal reflux disease (GERD). Drugs with anticholinergic properties, such as tricyclic antidepressants (TCAs), may facilitate GERD by a relaxing effect on the LES.

AIM

To investigate whether the use of TCAs is associated with an increased risk of reflux esophagitis (RE).

METHOD

A population-based case-control study was conducted within a large Dutch primary care database over the period 1996-2005. Cases with endoscopy-confirmed RE were identified and matched with up to 10 controls on gender, age, GP practice, and calendar time. Exposure to TCAs was assessed in the year prior to diagnosis and categorized as current (last prescription covered or ended within one month prior to the index date), past, and no use. The relative risk of RE was estimated by odds ratios (OR) with 95% confidence intervals (95% CI) using multivariate conditional logistic regression analysis.

RESULTS

During the study period, 1,462 cases with endoscopy-confirmed RE were identified. The risk of RE was increased in current TCA users (OR(adj) 1.61, 95% CI 1.04-2.50). Drug-specific analyses revealed that only clomipramine was associated with an increased risk of RE (OR(adj) 4.6, 95% CI 2.0-10.6) in a duration- and dose-dependent manner (OR(adj) 7.1, 95% CI 2.7-19.2 for use >180 days and OR(adj) 9.2, 95% CI 1.6-51.5 for >1 DDD equivalent/day).

CONCLUSION

No association was observed between the risk of RE and the use of TCAs other than clomipramine. The association between RE and clomipramine might be drug-related or a result of the underlying indication.

The GABA(B) receptor agonist AZD9343 inhibits transient lower oesophageal sphincter relaxations and acid reflux in healthy volunteers: a phase I study

BACKGROUND

Transient lower oesophageal sphincter relaxations (TLESRs) represent an interesting target for the treatment of gastro-oesophageal reflux. Baclofen reduces TLESRs and reflux episodes, but is not optimal for clinical application because of its central side effects. Therefore, new agents are required.

AIM

To study the effect of AZD9343, a new selective GABA(B) receptor agonist, in healthy volunteers.

METHODS

A total of 27 subjects participated in a placebo-controlled, randomized, two-centre phase I study. Subjects underwent oesophageal manometry and pH-metry for 3 h postprandially. Before meal ingestion, a single oral dose of placebo, 60 and 320 mg AZD9343 or 40 mg baclofen was given on four separate days.

RESULTS

Somnolence was reported after 320 mg AZD9343 and baclofen. Reversible short-lasting paraesthesia was reported after AZD9343. AZD9343 320 mg and baclofen significantly reduced the number of TLESRs with 32% and 40% respectively. Acid reflux was significantly decreased by AZD9343 and baclofen. Like baclofen, AZD9343 increased LES pressure before meal intake. AZD9343 320 mg and baclofen significantly reduced the swallowing rate.

CONCLUSIONS

Like baclofen, AZD9343 dose-dependently decreases the number of TLESRs and acid reflux episodes, increases LES pressure and reduces swallowing, extending the concept that GABA(B) agonists are potent reflux inhibitors. However, discovery of analogues with an improved side effect profile is warranted.

Prolonged esophagitis after primary dysfunction of the pyloric sphincter in the rat and therapeutic potential of the gastric pentadecapeptide BPC 157

Seven or fourteen days or twelve months after suturing one tube into the pyloric sphincter (removed by peristalsis by the seventh day), rats exhibit prolonged esophagitis with a constantly lowered pressure not only in the pyloric, but also in the lower esophageal sphincter and a failure of both sphincters. Throughout the esophagitis experiment, gastric pentadecapeptide BPC 157 (PL 14736) is given intraperitoneally once a day (10 microg/kg, 10 ng/kg, last application 24 h before assessment), or continuously in drinking water at 0.16 microg/ml, 0.16 ng/ml (12 ml/rat per day), or directly into the stomach 5 min before pressure assessment (a water manometer connected to the drainage port of a Foley catheter implanted into the stomach either through an esophageal or duodenal incision). This treatment alleviates i) the esophagitis (macroscopically and microscopically, at either region or interval), ii) the pressure in the pyloric sphincter, and iii) the pressure in the lower esophageal sphincter (cmH2O). In the normal rats it increases lower esophageal sphincter pressure, but decreases the pyloric sphincter pressure. Ranitidine, given using the same protocol (50 mg/kg, intraperitoneally, once daily; 0.83 mg/ml in drinking water; 50 mg/kg directly into the stomach) does not have an effect in either rats with esophagitis or in normal rats.

The effect of Flos Lonicerae Japonicae extract on gastro-intestinal motility function

ETHNOPHARMACOLOGICAL RELEVANCE

Flos Lonicerae Japonicae is a well-known herb of traditional Chinese medicine that has been used for heat-clearing, detoxification, anti-inflammation, throat pain and gastro-intestinal (GI) disorder. In order to verify the effect of Flos Lonicerae Japonicae on GI disorder, we investigated the prokinetic effect of GC-7101 on GI motility function.

MATERIALS AND METHODS

GC-7101 is the standardized extract of Flos Lonicerae Japonicae. The contractile action of GC-7101 on feline esophageal smooth muscle cell (ESMC) was evaluated by measuring dispersed cell length. The isometric tension study was performed to investigate the effect of GC-7101 on feline lower esophageal sphincther (LES). The prokinetic effect of GC-7101 was investigated by gastric emptying (GE) and gastro-intestinal transit (GIT) in rats.

RESULTS

GC-7101 produced concentration-dependent contractions in ESMCs. Pretreatment with 5-HT3 and 5-HT4 receptor blocker (ondansetron and GR113808) inhibited the contractile responses of the GC-7101-induced ESMCs. In isometric tension study, GC-7101 recovered the HCl-induced decreased tone of LES muscle strips. The treatment of GC-7101 enhanced the carbachol-induced contractile responses and the electric field stimulation (EFS)-induced on-contraction. The oral administration of GC-7101 not only significantly accelerated GE and GIT in normal rats but also recovered the delayed GE and GIT, and its effect was more potent than that of conventional prokinetics (e.g., domperidone, a dopamine-receptor antagonist, and mosapride, a 5-HT4-receptor agonist).

CONCLUSION

GC-7101 revealed a prokinetic effect through enhancing the contractile responses of ESMCs, tone increases, enhancing the carbarchol- or EFS-induced contractile responses of LES muscle strips, and the acceleration of GE and GIT. We have identified the significant potential of GC-7101 for the development of new prokinetic drugs through this study.

Effects of cricoid pressure and remifentanil on the esophageal sphincters using high-resolution solid-state manometry

BACKGROUND

Cricoid pressure has been shown to decrease the pressure in the lower esophageal sphincter (LES), increasing the risk of aspiration. Whether this reaction is due to pain associated with the application of cricoid pressure has not been studied. The aim of this study was to compare the effects of cricoid pressure with those of peripheral pain on pressures in the LES, and to study whether remifentanil influences these effects. Data from the upper esophageal sphincter (UES) are also described.

METHODS

Continuous solid-state manometry was performed in 14 healthy volunteers. Initially, the effect of remifentanil (target-controlled infusion with a plasma target concentration of 5.0 ng/ml) was studied, and thereafter, the effects of cricoid pressure and peripheral pain stimulation (cold stimulation). Finally, these two interventions were repeated under ongoing remifentanil infusion.

RESULTS

Remifentanil decreased the LES pressure significantly [ΔP-6.5 mmHg, 95% confidence interval (95% CI) -1.7 to -11.2]. Cricoid pressure application decreased the LES pressure significantly (ΔP-3.7 mmHg, 95% CI -1.4 to 6.1), whereas peripheral pain did not (ΔP 1.2 mmHg, 95% CI -3.5 to 1.1). Under ongoing remifentanil infusion, no cricoid pressure-induced LES relaxation was observed. Cricoid pressure induced high pressures in the area of the UES, 215.7 (±91.2) mmHg without remifentanil vs. 219.4 (±74.2) mmHg with remifentanil.

CONCLUSIONS

Remifentanil as well as cricoid pressure per se induced decreases in LES pressure. However, cricoid pressure-induced changes of the barrier pressure were not significant whether induced with or without an infusion of remifentanil.