Neuro-regulation of lower esophageal sphincter function as treatment for gastroesophageal reflux disease

Effects of dexmedetomidine on pharyngeal swallowing and esophageal motility-A double-blind randomized cross-over study in healthy volunteers

BACKGROUND

Sedative agents increase the risk of pulmonary aspiration, where an intact swallowing function is an important defense mechanism. Dexmedetomidine is an α2 -adrenoceptor agonist widely used during procedural sedation due to beneficial properties with minimal respiratory effects. The effects of dexmedetomidine on pharyngeal swallowing and esophageal motility are not known in detail.

METHODS

To determine the effects of dexmedetomidine on pharyngeal swallowing and esophageal motility, nineteen volunteers were included in this double-blinded, randomized placebo-controlled cross-over study. Study participants received target-controlled dexmedetomidine and placebo infusions. Recordings of pressure and impedance data were acquired using a manometry and impedance solid-state catheter. Data were analyzed from three bolus swallows series: baseline, during dexmedetomidine/placebo infusion at target plasma concentrations 0.6 ng ml-1 and 1.2 ng ml-1 . Subjective swallowing difficulties were also recorded.

KEY RESULTS

On pharyngeal swallowing, dexmedetomidine affected the upper esophageal sphincter with decreased pre- and post-swallow contractile pressures and an increase in residual pressure during swallow-related relaxation. On esophageal function, dexmedetomidine decreased contractile vigor of the proximal esophagus and increased velocity of the peristaltic contraction wave. Residual pressures during swallow-related esophagogastric junction (EGJ) relaxation decreased, as did basal EGJ resting pressure. The effects on the functional variables were not clearly dose-dependent, but mild subjective swallowing difficulties were more common at the higher dose level.

CONCLUSIONS AND INFERENCES

Dexmedetomidine induces effects on pharyngeal swallowing and esophageal motility, which should be considered in clinical patient management and also when a sedative agent for procedural sedation or for manometric examination is to be chosen.

Effects of Coffee on the Gastro-Intestinal Tract: A Narrative Review and Literature Update

The objective of the present research was to review the state of the art on the consequences of drinking coffee at the different levels of the gastrointestinal tract. At some steps of the digestive process, the effects of coffee consumption seem rather clear. This is the case for the stimulation of gastric acid secretion, the stimulation of biliary and pancreatic secretion, the reduction of gallstone risk, the stimulation of colic motility, and changes in the composition of gut microbiota. Other aspects are still controversial, such as the possibility for coffee to affect gastro-esophageal reflux, peptic ulcers, and intestinal inflammatory diseases. This review also includes a brief summary on the lack of association between coffee consumption and cancer of the different digestive organs, and points to the powerful protective effect of coffee against the risk of hepatocellular carcinoma. This review reports the available evidence on different topics and identifies the areas that would most benefit from additional studies.

Chronic REM-sleep deprivation induced laryngopharyngeal reflux in rats: A preliminary study

OBJECTIVE

The aim of this study was to investigate the relationship of chronic REM-sleep deprivation with laryngopharyngeal reflux (LPR) and its mechanism.

METHODS

Forty healthy male SD rats (body weight 250-280 g) were randomly divided into four groups. The first three ones were test group, which underwent REM-sleep deprivation with different duration of time by modified multiplatform water surface method. The last group was the control one having normal sleep. All the animals were performed Dx-pH monitoring when finishing sleep deprivation, and sacrificed to study the gastric residual rate (GRR) and small intestine peristalsis (SPR) rate by charcoal meal method.

RESULTS

At prone position, the reflux incidence in the test groups fairly increased with the duration of sleep deprivation (p<0.05). The total number of reflux episodes at prone position in the test group rats with 3 months duration of sleep deprivation was significantly increased compared with that in the control ones (p<0.05). GRR in rats experiencing sleep deficiency for different duration all reduced significantly when compared to the control group (p<0.05). GRR and SPR presented continuous decline tendency with the duration of sleep deprivation (p>0.05).

CONCLUSIONS

It is suggested that chronic sleep deficiency could cause LPR in rats, which might result from the uncoordinated digestive tract motility caused by dysfunction of central nervous system after chronic REM-sleep deprivation. Our results implied that chronic REM-sleep deprivation might be one of the causes of LPR. Addressing sleep problems might help to decrease the prevalence of LPR and enhance its treatment efficacy.

Design and Experimental Research of Implantable Lower Esophageal Sphincter Stimulator Based on Android Bluetooth

The aim of this study is to design an implantable Lower Esophageal Sphincter (LES) stimulator connected and controlled by an Android Bluetooth for the treatment of the gastroesophageal reflux disease (GERD). Then the animal experiments are carried out to evaluate the function of the system. The LES stimulator is composed of an external controller, an Android application (APP) via a smart phone and an implantable electronic device (IED). The external controller is designed to receive the settings parameters information sent by the Android APP via a Bluetooth module, and then is programmed to generate specific electrical stimulation pulses to the LES. The Android APP controls the start and stop of stimulation and the settings of stimulation parameters. The in vivo IED consists of a bipolar stimulating lead, a bipolar head connector and a receiving module. The bipolar stimulating lead is constructed of biocompatible materials: platinum-iridium electrodes which are coated with parylene and an outer silicone rubber sheathing. The size of the receiving module has been significantly decreased to 20×20×2 mm³, which is packaged by polydimethylsiloxane (PDMS) and proposed to deliver stimulation pulses from the external controller to the implantable lead. The one-month implantation experiment on rabbits has been performed to evaluate the LES stimulator. The results indicate that the proposed LES stimulator meets the requirements of the functions, effectiveness and safety.

Development of scores assessing the refluxogenic potential of diet of patients with laryngopharyngeal reflux

OBJECTIVE

To develop clinical tools assessing the refluxogenic potential of foods and beverages (F&B) consumed by patients with laryngopharyngeal reflux (LPR).

METHODS

European experts of the LPR Study group of the Young-Otolaryngologists of the International Federation of Oto-rhino-laryngological societies were invited to identify the components of Western European F&B that would be associated with the development of LPR. Based on the list generated by experts, four authors conducted a systematic review to identify the F&B involved in the development of esophageal sphincter and motility dysfunctions, both mechanisms involved in the development of gastroesophageal reflux disease and LPR. Regarding the F&B components and the characteristics identified as important in the development of reflux, experts developed three rational scores for the assessment of the refluxogenic potential of F&B, a dish, or the overall diet of the patient.

RESULTS

Twenty-six European experts participated to the study and identified the following components of F&B as important in the development of LPR: pH; lipid, carbohydrate, protein composition; fiber composition of vegetables; alcohol degree; caffeine/theine composition; and high osmolality of beverage. A total of 72 relevant studies have contributed to identifying the Western European F&B that are highly susceptible to be involved in the development of reflux. The F&B characteristics were considered for developing a Refluxogenic Diet Score (REDS), allowing a categorization of F&B into five categories ranging from 1 (low refluxogenic F&B) to 5 (high refluxogenic F&B). From REDS, experts developed the Refluxogenic Score of a Dish (RESDI) and the Global Refluxogenic Diet Score (GRES), which allow the assessment of the refluxogenic potential of dish and the overall diet of the LPR patient, respectively.

CONCLUSION

REDS, RESDI and GRES are proposed as objective scores for assessing the refluxogenic potential of F&B composing a dish or the overall diet of LPR patients. Future studies are needed to study the correlation between these scores and the development of LPR according to impedance-pH 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.

Antidepressant-mediated gastroesophageal reflux disease

Anticholinergic effects of medications are factors in autonomic control of the lower esophageal sphincter function. Changes in sphincter control often lead to gastroesophageal reflux disease (GERD), a chronic disease with a prevalence of up to 25% for adults. This effect is a consideration in the treatment of depression, the fourth-leading disease burden. Lower esophageal-sphincter changes are well documented in association with tricyclic antidepressants. The newer medications, selective serotonin-reuptake inhibitors and serotonin-norepinephrine reuptake inhibitors, are often used as first-line agents. This case report reviews the emergence of GERD in association with the use of newer agents. The patient, a 55-year-old woman, presented to her primary care physician with complaints of low energy, dysphoric mood, and anhedonia of several months' duration. Trials of citalopram and escitalopram were associated with reports of persistent nausea and gastric reflux unresolved by changes in dosing schedule or positioning. Over-the-counter omeprazole on an as-needed basis was added. Ultimately, the patient was successfully managed with desvenlafaxine for dysphoric mood and low energy and scheduled administration of omeprazole for GERD. The adverse drug reaction was evaluated using the Naranjo Adverse Drug Reaction Probability Scale. This methodology indicated a probable relationship (score of 7 out of 12) between initiation of antidepressant therapy and the presentation of GERD symptoms. When evaluating patient response to medication, inquiring about new-onset symptoms may help assess pharmacotherapy, identify potential medication-related effects such as the anticholinergic profile, evaluate the need to add an antisecretory/antispasmodic agent, or consider an alternative treatment strategy.

Effect of electrical stimulation of the lower esophageal sphincter using endoscopically implanted temporary stimulation leads in patients with reflux disease

BACKGROUND

Electrical stimulation therapy (EST) has been shown to increase lower esophageal sphincter (LES) pressure in animals; however, data on the effect of EST on LES pressure in patients with gastroesophageal reflux disease (GERD) are lacking.

OBJECTIVE

The aim of our study was to investigate the effect of EST on LES pressure and esophageal function in patients with GERD.

METHODS

Patients with a diagnosis of GERD responsive to proton pump inhibitors (PPIs), increased esophageal acid on 24-h pH monitoring off GERD medications, basal LES pressure >5 mmHg, hernia <2 cm and esophagitis <LA grade B were included. A temporary pacemaker lead was placed endoscopically in the LES by creating a 3 cm submucosal tunnel, secured to the esophagus using endoscopic clips along the body of the lead and exteriorized nasally. EST was delivered 6-12 h post-implant per protocol using (i) short-pulse 200 μs, 20 Hz, and (ii) intermediate-pulse 3 ms, 20 Hz, each for 20 min at varying amplitudes. High-resolution manometry was performed pre-, during and post-EST. Symptoms of heartburn, chest or abdominal pain and dysphagia pre-, during and post-stimulation and 7 days post-procedure were recorded. Continuous cardiac monitoring was performed during and after the EST to evaluate any effect of EST on cardiac rhythm.

RESULTS

Six male patients (mean age 34.6 years) underwent successful endoscopic lead implantation; the first patient had premature lead dislodgement and did not undergo EST. The remaining five patients underwent successful EST. All patients had a significant increase in LES pressure with all sessions of EST. There was no effect on swallow-induced LES relaxation, And there were no EST-related adverse symptoms or any cardiac rhythm abnormalities.

CONCLUSIONS

In patients with GERD, short-term EST delivered using electrodes endoscopically implanted in the LES results in a significant increase in LES pressure without affecting patients' swallow function or causing any adverse symptoms or cardiac rhythm disturbances. EST may offer a novel therapy to patients with GERD.

Increase of lower esophageal sphincter pressure after osteopathic intervention on the diaphragm in patients with gastroesophageal reflux

The treatment of gastroesophageal reflux disease may be clinical or surgical. The clinical consists basically of the use of drugs; however, there are new techniques to complement this treatment, osteopathic intervention in the diaphragmatic muscle is one these. The objective of the study is to compare pressure values in the examination of esophageal manometry of the lower esophageal sphincter (LES) before and immediately after osteopathic intervention in the diaphragm muscle. Thirty-eight patients with gastroesophageal reflux disease - 16 submitted to sham technique and 22 submitted osteopathic technique - were randomly selected. The average respiratory pressure (ARP) and the maximum expiratory pressure (MEP) of the LES were measured by manometry before and after osteopathic technique at the point of highest pressure. Statistical analysis was performed using the Student's t-test and Mann-Whitney, and magnitude of the technique proposed was measured using the Cohen's index. Statistically significant difference in the osteopathic technique was found in three out of four in relation to the group of patients who performed the sham technique for the following measures of LES pressure: ARP with P= 0.027. The MEP had no statistical difference (P= 0.146). The values of Cohen d for the same measures were: ARP with d= 0.80 and MEP d= 0.52. Osteopathic manipulative technique produces a positive increment in the LES region soon after its performance.

WHAT IS THE REAL IMPAIRMENT ON ESOPHAGEAL MOTILITY IN PATIENTS WITH GASTROESOPHAGEAL REFLUX DISEASE?

Context Impairment of esophageal motility is a common finding in patients with gastroesophageal reflux disease (GERD) as reduced lower esophageal sphincter (LES) basal pressure. A very low LES pressure might facilitate the occurrence of more gastroesophageal reflux whereas abnormal esophageal peristalsis may contribute to impaired esophageal clearance after reflux. Objective Evaluate the esophageal motor function of the lower esophageal sphincter and esophageal body in the various forms of gastroesophageal reflux disease. Methods The manometrics records of 268 patients, who had evaluation of the esophageal motility as part of the diagnostic gastroesophageal reflux disease were split into four groups, as follows: 33 patients who had no esophagitis; 92 patients who had erosive esophagitis; 101 patients who had short Barrett's esophagus and 42 patients who had long Barrett's esophagus. Results The group who had long Barrett's esophagus showed smaller mean LES pressure and higher percentage of marked LES hypotonia; in the distal segment of the esophageal body the this group showed higher percentage of marked hypocontractility of the distal segment (<30 mm Hg); this same group showed higher percentage of esophageal motility disorders. Conclusions The most intense esophageal motility disorders and lower pressure of lower esophageal sphincter were noted in the group with long Barrett's esophagus. Those with reflux esophagitis and short Barrett's esophagus had esophageal motility impairment, intermediate among patients with esophagitis and long Barrett's esophagus. Patients with typical symptoms of gastroesophageal reflux but without esophagitis by endoscopy study showed no impairment of esophageal motility.

The effect of rabeprazole on LES tone in experimental rat model

INTRODUCTION

Despite adequate treatment with proton pump inhibitors (PPIs), symptoms of gastroesophageal reflux disease (GERD) may remain persistent as well as Barrett's esophagus may emerge. It may be proposed that the relaxant effect of PPIs on the smooth muscles may lead to resistance of symptoms. The aim of this study is to investigate effects of rabeprazole on the lower esophageal sphincter (LES) pressure with a rat model.

MATERIALS AND METHODS

Sixteen rats were grouped as control and treatment groups. After obtaining LES tissues followed by a 60 min equilibration period for stabilization, contractile response to carbachol was obtained by application of single dose of carbachol to have a final concentration of 10(-6) M in the organ bath. After the contractions reached a plateau, concentration-response relationships for rabeprazole were obtained in a cumulative manner in the treatment group.

RESULTS

In the carbachol contracted LES preparations; 1.5 × 10(-6) and 1.5×10(-5) M of rabeprazole caused 6.08% and 11.34% relaxations respectively which were not statistically significant. However, mean integral relaxation value for 4.5 × 10(-5) M of rabeprazole was 17.34% and this relaxation was significant compared with controls.

CONCLUSIONS

In the present study, rabeprazole caused no direct significant change in LES tone in the therapeutic dose range applied to the organ bath. However, rabeprazole at the high dose caused a significant decrease in the LES tone.

Clozapine and gastro-oesophageal reflux disease (GORD) - an investigation of temporal association

OBJECTIVE

To establish the temporal relationship between prescription of acid-suppressant therapy, GORD and clozapine prescribing.

METHOD

In this retrospective cohort study, we identified out-patients prescribed clozapine and other atypical antipsychotics (AAP) and compared times and rates of prescribing of acid-suppressant therapy. Odds ratios were calculated.

RESULTS

Of 352 patients on clozapine and 358 patients on other AAP, there were 74 (21.0%) and 23 (6.7%) patients prescribed acid-suppressant therapy respectively [OR = 3.9 (95% CI: 2.4-6.4) P ≤ 0.0001]. In 67 of 74 cases (90.5%) vs. 18 of 23 cases (81.8%), acid-suppressant therapy began after the start of the antipsychotic. Clozapine patients were more likely to be prescribed acid-suppressant therapy within the first 5 years of initiation than those on other AAP (P = 0.039). Where indication for acid-suppressant therapy was known, it was prescribed for GORD in 44 of 62 (71.0%) of the clozapine patients and 6 of 13 (46.2%) of those on other AAP (P = 0.109). Rate of known GORD was 44 of 352 (12.5%) for clozapine and 6 of 358 (1.7%) for other atypicals [OR = 8.4 (95% CI: 3.5-19.9) P ≤ 0.0001].

CONCLUSION

Clozapine was associated with higher rates of GORD and acid-suppressant therapy prescribing than other AAP. There was a clear temporal relationship between the prescribing of clozapine and the later use of acid-suppressant therapy. These observations strongly suggest that prescription of clozapine was associated with the onset of GORD.

Pentadecapeptide BPC 157 and the esophagocutaneous fistula healing therapy

Esophagocutaneous fistulas are a failure of the NO-system, due to NO-synthase blockage by the NOS-blocker L-NAME consequently counteracted by l-arginine and gastric pentadecapeptide BPC 157 (l-arginine <BPC 157), precipitating a therapeutic benefit. Previously, there was an established BPC 157-NO-system interaction. BPC 157 GEPPPGKPADDAGLV, MW 1419 (LD1 not achieved), is a safe and stable anti-ulcer peptide, successful in inflammatory bowel disease trials, counteracting esophagitis, sphincter failure, gastrointestinal and skin ulcers, gastrocutaneous or colocutaneous fistulas. We treated rats with established cervical esophagocutaneous fistulas throughout four days (both open skin and esophageal defects, with significant leakage) with BPC 157 (parenterally and perorally) and L-NAME (blocking NO genesis) and l-arginine (NO-substrate) alone or in combination. RT-PCR investigated eNOS, iNOS, COX-2 mRNA levels in the fistulas. We evidenced a closely inter-related process of unhealed skin, esophageal defects, unhealed fistulas (up regulated eNOS, iNOS and COX2 mRNA levels), usually lethal, particularly NO-system related and therapy dependent. Generally, the course of fistula healing was accelerated either to a greater extent (with BPC 157 (in particular, less eNOS gene expression) completely counteracting L-NAME effects, in L-NAME+BPC 157 and L-NAME+l-arginine+BPC 157 groups), or to a lesser extent (with l-arginine). Conversely, the process was aggravated, rapidly and prominently (with L-NAME). In particular, BPC 157 was effective either given per-orally/intraperitoneally, in μg- and ng-regimens. Shortly, defects started to heal, with less fistula leakage and no mortality at day 4. Failure of pyloric and lower esophageal sphincter pressure was restored, with practically no esophagitis.

Vagal sensory innervation of the gastric sling muscle and antral wall: implications for gastro-esophageal reflux disease?

BACKGROUND

The gastric sling muscle has not been investigated for possible sensory innervation, in spite of the key roles the structure plays in lower esophageal sphincter (LES) function and gastric physiology. Thus, the present experiment used tracing techniques to label vagal afferents and survey their projections in the lesser curvature.

METHODS

Sprague-Dawley rats received injections of dextran biotin into the nodose ganglia. Fourteen days postinjection, animals were euthanized and their stomachs were processed to visualize the vagal afferent innervation. In different cases, neurons, muscle cells, or interstitial cells of Cajal (ICC) were counterstained.

KEY RESULTS

The sling muscle is innervated throughout its length by vagal afferent intramuscular arrays (IMAs) associated with ICC. In addition, the distal antral attachment site of the sling muscle is innervated by a novel vagal afferent terminal specialization, an antral web ending. The muscle wall of the distal antrum is also innervated by conventional IMAs and intraganglionic laminar endings, the two types of mechanoreceptors found throughout stomach smooth muscle.

CONCLUSIONS & INFERENCES

The innervation of sling muscle by IMAs, putative stretch receptors, suggests that sling sensory feedback may generate vago-vagal or other reflexes with vagal afferent limbs. The restricted distribution of afferent web endings near the antral attachments of sling fibers suggests the possibility of specialized mechanoreceptor functions linking antral and pyloric activity to the operation of the LES. Dysfunctional sling afferents could generate LES motor disturbances, or normative compensatory sensory feedback from the muscle could compromise therapies targeting only effectors.

Research progress of enteric nervous system in esophagus

The functions of esophageal peristalsis and contraction were regulated and controlled by both neural and humoral system at all levels. Esophageal function depends on coordination of all the effectors regulated by enteric nervous system (ENS). Esophageal neurons are generally divided into two groups: the excitatory neurons and the inhibitory neurons. They regulate the tone, peristalsis and contraction of esophagus by interaction of various neurotransmitters. This article reviews recent research advancement of ENS in esophagus.