Systemic pharmacomodulation of transient lower esophageal sphincter relaxations

Association between hiatal hernia and Barrett's esophagus: an updated meta-analysis with trial sequential analysis

Background

Barrett's esophagus (BE) is a precursor of esophageal adenocarcinoma. It is critical to recognize the risk factors associated with BE.

Objectives

The present meta-analysis aims to systematically estimate the association of hiatal hernia with the risk of BE.

Design

A meta-analysis with trial sequential analysis.

Data sources and methods

The PubMed, EMBASE, and Cochrane Library databases were searched. The pooled odds ratios (ORs) and adjusted ORs (aORs) with their 95% confidence intervals (CIs) were calculated for the combined estimation of unadjusted data and data adjusted for confounders, respectively. Heterogeneity was quantified using the Cochrane Q test and I² statistics. Subgroup, meta-regression, and leave-one-out sensitivity analyses were employed to explore the sources of heterogeneity.

Results

Forty-seven studies with 131,517 participants were included. Based on the unadjusted data from 47 studies, hiatal hernia was significantly associated with an increased risk of any length BE (OR = 3.91, 95% CI = 3.31-4.62, p < 0.001). The heterogeneity was significant (I² = 77%; p < 0.001) and the definition of controls (p = 0.014) might be a potential contributor to heterogeneity. Based on the adjusted data from 14 studies, this positive association remained (aOR = 3.26, 95% CI = 2.44-4.35, p < 0.001). The heterogeneity was also significant (I² = 65%; p < 0.001). Meta-analysis of seven studies demonstrated that hiatal hernia was significantly associated with an increased risk of long-segment BE (LSBE) (OR = 10.01, 95% CI = 4.16-24.06, p < 0.001). The heterogeneity was significant (I² = 78%; p < 0.001). Meta-analysis of seven studies also demonstrated that hiatal hernia was significantly associated with an increased risk of short-segment BE (OR = 2.76, 95% CI = 2.05-3.71, p < 0.001). The heterogeneity was not significant (I² = 30%; p = 0.201).

Conclusion

Hiatal hernia should be a significant risk factor for BE, especially LSBE.

Registration

PROSPERO registration number CRD42022367376.

Inspiratory muscle training improves antireflux barrier in GERD patients

The crural diaphragm (CD) is an essential component of the esophagogastric junction (EGJ), and inspiratory exercises may modify its function. This study's goal is to verify if inspiratory muscle training (IMT) improves EGJ motility and gastroesophageal reflux (GER). Twelve GER disease [GERD; 7 males, 20-47 yr, 9 esophagitis, and 3 nonerosive reflex disease (NERD)] and 7 healthy volunteers (3 males, 20-41 yr) performed esophageal pH monitoring, manometry, and heart rate variability (HRV) studies. A 6-cm sleeve catheter measured average EGJ pressure during resting, peak inspiratory EGJ pressures during sinus arrhythmia maneuver (SAM) and inhalations under 17-, 35-, and 70-cmH2O loads (TH maneuvers), and along 1 h after a meal. GERD patients entered a 5-days-a-week IMT program. One author scored heartburn and regurgitation before and after IMT. IMT increased average EGJ pressure (19.7 ± 2.4 vs. 29.5 ± 2.1 mmHg; P < 0.001) and inspiratory EGJ pressure during SAM (89.6 ± 7.6 vs. 125.6 ± 13.3 mmHg; P = 0.001) and during TH maneuvers. The EGJ-pressure gain across 35- and 70-cmH2O loads was lower for GERD volunteers. The number and cumulative duration of the transient lower esophageal sphincter relaxations decreased after IMT. Proximal progression of GER decreased after IMT but not the distal acid exposure. Low-frequency power increased after IMT and the higher its increment the lower the increment of supine acid exposure. IMT decreased heartburn and regurgitation scores. In conclusion, IMT improved EGJ pressure, reduced GER proximal progression, and reduced GERD symptoms. Some GERD patients have a CD failure, and IMT may prove beneficial as a GERD add-on treatment.

The relevance of transient lower oesophageal sphincter relaxations in the pathophysiology and treatment of GORD

Gastro-oesophageal reflux disease (GORD) is associated with the passage of gastric contents into the oesophagus resulting in potential oesophageal damage and impaired quality of life. GORD is a frequently encountered problem in today's population, with 25% of people in western populations reporting such symptoms at least once a month. Proton pump inhibitors (PPI) are the drug of choice, with surgery being employed in refractory cases. Although acid suppression is often effective, some patients remain symptomatic despite maximal PPI therapy. By delving into the mechanisms of the disease, it is clear that transient lower oesophageal sphincter relaxations are a key component of its pathophysiology. Research has demonstrated various therapeutic targets for reducing the frequency of such relaxations through GABA and glutamate modulation, for instance. This review highlights such modulations and hopes to explore these mechanisms and therapeutic targets in an area that will no doubt see a change in its pharmacological management in the near future.

Airway reflux, cough and respiratory disease

It is increasingly accepted that the effects of gastro-oesophageal reflux are not limited to the gastrointestinal tract. The adjacent respiratory structures are also at risk from material ejected from the proximal oesophagus as a result of the failure of anatomical and physiological barriers. There is evidence of the influence of reflux on several respiratory and otorhinological conditions and although in many cases the precise mechanism has yet to be elucidated, the association alone opens potential novel avenues of therapy to clinicians struggling to treat patients with apparently intractable respiratory complaints. This review provides a description of the airway reflux syndrome, its effects on the lung and current and future therapeutic options.

Which is the best choice for gastroesophageal disorders: Melatonin or proton pump inhibitors?

Melatonin is used in many countries to improve sleep disorders. Melatonin is a hormone produced by the pineal gland and enterochromaffin cells which control sleep and gastrointestinal motility. Low levels of melatonin lead to gastroesophageal reflux disease (GERD). Most of patients with GERD have a sleep disorder. So, low melatonin levels is the main cause of insomnia. Beyond this, it has an inhibitory action on gastric acid secretion and seems to control the lower esophageal sphincter. Proton pump inhibitors (PPIs) are a group of drugs whose main action is a pronounced and long-lasting reduction of gastric acid production. They are the most potent inhibitors of acid secretion available today. Omeprazole (one of the PPIs) and melatonin have similarities in their chemical structures. Therefore, we could consider omeprazole as a rough copy of melatonin. In this paper, we compare the advantages and disadvantages of the clinical use of melatonin and PPIs.

Relationship between gastro-oesophageal reflux and airway diseases: the airway reflux paradigm

Our understanding of the relationship between gastro-oesophageal reflux and respiratory disease has recently undergone important changes. The previous paradigm of airway reflux as synonymous with the classic gastro-oesophageal reflux disease (GORD) causing heartburn has been overturned. Numerous epidemiological studies have shown a highly significant association of the acid, liquid, and gaseous reflux of GORD with conditions such as laryngeal diseases, chronic rhinosinusitis, treatment resistant asthma, COPD and even idiopathic pulmonary fibrosis. However, it has become clear from studies on cough hypersensitivity syndrome that much reflux of importance in the airways has been missed, since it is either non- or weakly acid and gaseous in composition. The evidence for such a relationship relies on the clinical history pointing to symptom associations with known precipitants of reflux. The tools for the diagnosis of extra-oesophageal reflux, in contrast to the oesophageal reflux of GORD, lack sensitivity and reproducibility. Unfortunately, methodology for detecting such reflux is only just becoming available and much additional work is required to properly delineate its role.

Which is the best choice for gastroesophageal disorders: Melatonin or proton pump inhibitors?

Melatonin is used in many countries to improve sleep disorders. Melatonin is a hormone produced by the pineal gland and enterochromaffin cells which control sleep and gastrointestinal motility. Low levels of melatonin lead to gastroesophageal reflux disease (GERD). Most of patients with GERD have a sleep disorder. So, low melatonin levels is the main cause of insomnia. Beyond this, it has an inhibitory action on gastric acid secretion and seems to control the lower esophageal sphincter. Proton pump inhibitors (PPIs) are a group of drugs whose main action is a pronounced and long-lasting reduction of gastric acid production. They are the most potent inhibitors of acid secretion available today. Omeprazole (one of the PPIs) and melatonin have similarities in their chemical structures. Therefore, we could consider omeprazole as a rough copy of melatonin. In this paper, we compare the advantages and disadvantages of the clinical use of melatonin and PPIs.

Effect of delta9-tetrahydrocannabinol, a cannabinoid receptor agonist, on the triggering of transient lower oesophageal sphincter relaxations in dogs and humans

BACKGROUND AND PURPOSE

Transient lower oesophageal sphincter relaxations (TLESRs) are the main mechanism underlying gastro-oesophageal reflux and are a potential pharmacological treatment target. We evaluated the effect of the CB(1)/CB(2) receptor agonist delta(9)-tetrahydrocannabinol (delta(9)-THC) on TLESRs in dogs. Based on these findings, the effect of delta(9)-THC was studied in healthy volunteers.

EXPERIMENTAL APPROACH

In dogs, manometry was used to evaluate the effect of delta(9)-THC in the presence and absence of the CB(1) receptor antagonist SR141716A on TLESRs induced by gastric distension. Secondly, the effect of 10 and 20 mg delta(9)-THC was studied in 18 healthy volunteers in a placebo-controlled study. Manometry was performed before and for 3 h after meal ingestion on three occasions.

KEY RESULTS

In dogs, delta(9)-THC dose-dependently inhibited TLESRs and reduced acid reflux rate. SR141716A significantly reversed the effects of delta(9)-THC on TLESRs. Similarly, in healthy volunteers, delta(9)-THC significantly reduced the number of TLESRs and caused a non-significant reduction of acid reflux episodes in the first postprandial hour. In addition, lower oesophageal sphincter pressure and swallowing were significantly reduced by delta(9)-THC. After intake of 20 mg, half of the subjects experienced nausea and vomiting leading to premature termination of the study. Other side-effects were hypotension, tachycardia and central effects.

CONCLUSIONS AND IMPLICATIONS

Delta(9)-THC significantly inhibited the increase in meal-induced TLESRs and reduced spontaneous swallowing in both dogs and humans. In humans, delta(9)-THC significantly reduced basal lower oesophageal sphincter pressure. These findings confirm previous observations in dogs and indicate that cannabinoid receptors are also involved in the triggering of TLESRs in humans.

The effects of nebulized albuterol on esophageal function in asthmatic patients

PURPOSE

Albuterol reduces lower esophageal sphincter (LES) pressure in normal volunteers, although the effects of albuterol on esophageal function in asthmatic patients are not known. The aim of this study was to evaluate the effects of nebulized albuterol on lower esophageal function in asthmatic patients. Symptoms and a methacholine challenge test were used to identify asthmatic patients who were then enrolled in a prospective, randomized, placebo-controlled, double-blinded, crossover trial. Changes in esophageal function in response to nebulized albuterol or placebo were evaluated over two sessions spaced 1 week apart.

RESULTS

Albuterol induced a dose-dependent drop in lower esophageal sphincter basal pressure with a threshold dose as low as 2.5 mg. Albuterol did not affect the amplitude of esophageal contractions.

CONCLUSIONS

Nebulized albuterol induces a dose-dependent reduction in LES basal pressure in asthmatic patients. These effects raise the possibility that gastroesophageal reflux may occur after bronchodilator therapy.

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

The junction between the esophagus and the stomach is a specialized region, composed of lower esophageal sphincter (LES) and its adjacent anatomical structures, the gastric sling and crural diaphragm. Together these structures work in a coordinated manner to allow ingested food into the stomach while preventing reflux of gastric contents across the esophago-gastric junction (EGJ) into the esophagus. The same zone also permits retrograde passage of air and gastric contents into esophagus during belching and vomiting. The precise coordination required to execute such a complicated task is achieved by a finely-regulated high-pressure zone. This zone keeps the junction between esophagus and stomach continuously closed, but is still able to relax briefly via input from inhibitory neurons that are responsible for its innervation. Alterations of the structure and function of the EGJ and the LES may predispose to gastroesophageal reflux disease (GERD).

Anatomy and function of group III metabotropic glutamate receptors in gastric vagal pathways

Metabotropic glutamate receptors (mGluR) are classified into groups I (excitatory), II and III (inhibitory) mGluR. Activation of peripheral group III mGluR (mGluR4, mGluR6, mGluR7, mGluR8), particularly mGluR8, inhibits vagal afferent mechanosensitivity in vitro which translates into reduced triggering of transient lower oesophageal sphincter relaxations and gastroesophageal reflux in vivo. However, the expression and function of group III mGluR in central gastrointestinal vagal reflex pathways is not known. Here we assessed the expression of group III mGluR in identified gastric vagal afferents in the nodose ganglion (NG) and in the dorsal medulla. We also determined the central action of the mGluR8a agonist S-3,4-DCPG (DCPG) on nucleus tractus solitarius (NTS) neurons with gastric mechanosensory input in vivo. Labelling for mGluR4 and mGluR8 was abundant in gastric vagal afferents in the NG, at their termination site in the NTS (subnucleus gelatinosus) and in gastric vagal motorneurons, while labelling for mGluR6 and mGluR7 was weaker in these regions. DCPG (0.1 nmol or 0.001-10 nmol i.c.v.) inhibited or markedly attenuated responses of 8/10 NTS neurons excited by isobaric gastric distension with no effect on blood pressure or respiration; 2 NTS neurons were unaffected. The effects of DCPG were significantly reversed by the group III mGluR antagonist MAP4 (10 nmol, i.c.v.). In contrast, 4/4 NTS neurons inhibited by gastric distension were unaffected by DCPG. We conclude that group III mGluR are expressed in peripheral and central vagal pathways, and that mGluR8 within the NTS selectively reduce excitatory transmission along gastric vagal pathways.

Regression of gastroesophageal reflux disease symptoms using dietary supplementation with melatonin, vitamins and aminoacids: comparison with omeprazole

The prevalence of gastroesophageal reflux disease (GERD) is increasing. GERD is a chronic disease and its treatment is problematic. It may present with various symptoms including heartburn, regurgitation, dysphagia, coughing, hoarseness or chest pain. The aim of this study was to investigate if a dietary supplementation containing: melatonin, l-tryptophan, vitamin B6, folic acid, vitamin B12, methionine and betaine would help patients with GERD, and to compare the preparation with 20 mg omeprazole. Melatonin has known inhibitory activities on gastric acid secretion and nitric oxide biosynthesis. Nitric oxide has an important role in the transient lower esophageal sphincter relaxation (TLESR), which is a major mechanism of reflux in patients with GERD. Others biocompounds of the formula display anti-inflammatory and analgesic effects. A single blind randomized study was performed in which 176 patients underwent treatment using the supplement cited above (group A) and 175 received treatment of 20 mg omeprazole (group B). Symptoms were recorded in a diary and changes in severity of symptoms noted. All patients of the group A (100%) reported a complete regression of symptoms after 40 days of treatment. On the other hand, 115 subjects (65.7%) of the omeprazole reported regression of symptoms in the same period. There was statiscally significant difference between the groups (P < 0.05). This formulation promotes regression of GERD symptoms with no significant side effects.

Signals for nausea and emesis: Implications for models of upper gastrointestinal diseases

Nausea and vomiting are amongst the most common symptoms encountered in medicine as either symptoms of diseases or side effects of treatments. In a more biological setting they are also important components of an organism's defences against ingested toxins. Identification of treatments for nausea and vomiting and reduction of emetic liability of new therapies has largely relied on the use of animal models, and although such models have proven invaluable in identification of the anti-emetic effects of both 5-hydroxytryptamine(3) and neurokinin(1) receptor antagonists selection of appropriate models is still a matter of debate. The present paper focuses on a number of controversial issues and gaps in our knowledge in the study of the physiology of nausea and vomiting including: The choice of species for the study of emesis and the underlying behavioural (e.g. neophobia), anatomical (e.g. elongated, narrow abdominal oesophagus with reduced ability to shorten) and physiological (e.g. brainstem circuitry) mechanisms that explain the lack of a vomiting reflex in certain species (e.g. rats); The choice of response to measure (emesis[retching and vomiting], conditioned flavour avoidance or aversion, ingestion of clay[pica], plasma hormone levels[e.g. vasopressin], gastric dysrhythmias) and the relationship of these responses to those observed in humans and especially to the sensation of nausea; The stimulus coding of nausea and emesis by abdominal visceral afferents and especially the vagus-how do the afferents encode information for normal postprandial sensations, nausea and finally vomiting?; Understanding the central processing of signals for nausea and vomiting is particularly problematic in the light of observations that vomiting is more readily amenable to pharmacological treatment than is nausea, despite the assumption that nausea represents "low" intensity activation of pathways that can evoke vomiting when stimulated more intensely.

Physiology of reflux disease: role of the lower esophageal sphincter

The function of the lower esophageal sphincter (LES) has historically been elucidated by two major manometric methods: the one concentrating on static parameters including resting pressure, overall length, and intraabdominal length, and the other concentrating on the episodic loss of sphincter tone, termed "transient lower esophageal sphincter relaxations" (TLESRs). Both approaches yield valuable insights, but neither is all-encompassing. Both resting characteristics and the production of TLESRs are affected by many features in the typical western diet, including carbonated beverages. The authors hypothesize that repetitive distention resulting from such substances causes the LES to become transiently defective and reduces the threshold for the occurrence of TLESRs. Long-term defects of the resting parameters may reflect secondary damage to underlying muscle caused by increased reflux. The coexistence of hiatal hernia compounds the mechanical deficiency, and obesity also may contribute. Despite much research to reduce the frequency of TLESRs pharmacologically, restoration of the LES remains primarily within the realm of the surgeon.

Inhibition of transient lower esophageal sphincter relaxation and gastroesophageal reflux by metabotropic glutamate receptor ligands

BACKGROUND & AIMS

Transient lower esophageal sphincter relaxation (TLESR) is the major mechanism of gastroesophageal acid reflux. TLESR is mediated via vagal pathways, which may be modulated by metabotropic glutamate receptors (mGluRs). Group I mGluRs (mGluR1 and 5) have excitatory effects on neurons, whereas group II (mGluR2 and 3) and group III (mGluR4, 6, 7, and 8) are inhibitory. This study determined the effect of mGluRs on triggering of TLESR and reflux in an established conscious ferret model.

METHODS

Esophageal manometric/pH studies were performed in ferrets with chronic esophagostomies. TLESR were induced by a gastric load of 25 mL glucose (pH 3.5) and 30 mL air.

RESULTS

In control treated animals, gastric load induced 3.52 +/- 0.46 TLESRs per 47-minute study, 89.7% of which were associated with reflux episodes (n = 16). The mGluR5 antagonist MPEP inhibited TLESR dose dependently, with maximal 71% +/- 7% inhibition at 35 micromol/kg (n = 9; P < .0001). MPEP also significantly reduced reflux episodes (P < .001) and increased basal lower esophageal sphincter pressure (P < .05). MPEP inhibited swallowing dose dependently, suggesting a common action on trigger mechanisms for swallowing and TLESR. The more selective analogue, MTEP, had more potent effects (90% +/- 6% inhibition TLESR at 40 micromol/kg; n = 8; P < .0001). In contrast, the group I agonist DHPG tended to increase TLESR. The group II agonist (2R, 4R)-APDC was ineffective, whereas the group III agonist L-(AP4 slightly reduced TLESR (33% at 11 micromol/kg; P < .05). The selective mGluR8 agonist (S)-3, 4-DCPG inhibited TLESR by 54% at 15 micromol/kg (P < .01).

CONCLUSIONS

mGluR5 antagonists potently inhibit TLESR and reflux in ferrets, implicating mGluR5 in the mechanism of TLESR. mGluR5 antagonists are therefore promising as therapy for patients with GERD.

The endocannabinoid system in the physiology and pathophysiology of the gastrointestinal tract

Numerous investigations have recently demonstrated the important roles of the endocannabinoid system in the gastrointestinal (GI) tract under physiological and pathophysiological conditions. In the GI tract, cannabinoid type 1 (CB1) receptors are present in neurons of the enteric nervous system and in sensory terminals of vagal and spinal neurons, while cannabinoid type 2 receptors are located in immune cells. Activation of CB1 receptors was shown to modulate several functions in the GI tract, including gastric secretion, gastric emptying and intestinal motility. Under pathophysiological conditions induced experimentally in rodents, the endocannabinoid system conveys protection to the GI tract (e.g. from inflammation and abnormally high gastric and enteric secretions). Such protective activities are largely in agreement with anecdotal reports from folk medicine on the use of Cannabis sativa extracts by subjects suffering from various GI disorders. Thus, the endocannabinoid system may serve as a potentially promising therapeutic target against different GI disorders, including frankly inflammatory bowel diseases (e.g. Crohn's disease), functional bowel diseases (e.g. irritable bowel syndrome) and secretion- and motility-related disorders. As stimulation of this modulatory system by CB1 receptor agonists can lead to unwanted psychotropic side effects, an alternative and promising avenue for therapeutic applications resides in the treatment with CB1 receptor agonists that are unable to cross the blood-brain barrier, or with compounds that inhibit the degradation of endogenous ligands (endocannabinoids) of CB1 receptors, hence prolonging the activity of the endocannabinoid system.

Inhibition of transient lower esophageal sphincter relaxations by electrical acupoint stimulation

Acupuncture has been shown to modulate visceral sensation and function. Traditionally, stimulation at the Neiguan (pericardial meridian) has been used to treat upper gastrointestinal symptoms. Some of the effects of acupuncture may be mediated through release of endogenous opioids and are reversed by naloxone. Gastric distension is the major trigger for transient lower esophageal sphincter (LES) relaxations (TLESRs). The aim of this study was to investigate the effect of electric stimulation at the Neiguan and naloxone on the TLESRs. In 14 healthy volunteers, electrical acupoint stimulation was applied at the Neiguan and a sham point on the hip in randomized order on the same day. In 12 healthy volunteers, the effects of naloxone (80 microg/kg iv bolus injection) and saline on electrical acupoint stimulation were compared on separate days at least 1 wk apart. Esophageal motility was measured during distension of the proximal stomach with 500 ml of air using a barostat balloon. Electric acupoint stimulation at the Neiguan decreased the rate of TLESRs by approximately 40% from a median of 6/h to 3.5/h (P < 0.02). Acupoint stimulation had no effect on basal LES pressure, the residual LES pressure during TLESRs, the duration of TLESRs, or gastrointestinal symptoms of fullness, bloating, discomfort, or nausea. The effect of acupoint stimulation was not inhibited by naloxone. Electric acupoint stimulation at the Neiguan significantly inhibits the frequency of TLESRs in response to gastric distention in healthy subjects. This effect does not appear to be mediated through mu-opioid receptors.

Sleeve sensor versus high-resolution manometry for the detection of transient lower esophageal sphincter relaxations

Transient lower esophageal sphincter relaxations (TLESRs) are the most important mechanism by which gastroesophageal reflux occurs, and sleeve sensor manometry is the gold standard for detection of TLESRs. The aim of this study was to evaluate manometry with closely spaced sideholes (high-resolution manometry) for the detection of TLESRs as an alternative. In 12 patients with gastroesophageal reflux disease, a 90-min postprandial manometry was performed by using a catheter incorporating both a sleeve sensor and closely spaced sideholes in the esophagogastric junction. TLESRs recorded with both techniques were scored. Reflux during TLESRs was detected by using manometry (common cavity), intraluminal impedance, and pH monitoring. A total of 145 TLESRs were detected by using both techniques, 117 with high-resolution manometry and 108 with sleeve sensor manometry [not significant (NS)]. Manometric signs of reflux during TLESRs detected with high-resolution and sleeve sensor manometry were found in 62.4 and 56.5%, NS, respectively, versus 38.5 and 35.2%, NS on pH-metry and 70.1 and 60.2%, NS on impedance monitoring. TLESRs recognized only with high-resolution manometry were more often accompanied by reflux, as detected with manometry (59.5%) and impedance monitoring (67.6%), than TLESRs recognized only with sleeve sensor manometry (32.1 and 28.6%). High-resolution manometry is at least as accurate as sleeve sensor manometry for the detection of TLESRs.

Clinical presentation, diagnosis, and management of gastroesophageal reflux disease

GERD is ubiquitous throughout the adult population in the United States. It commonly adversely affects quality of life and occasionally causes life-threatening complications. The new and emerging medical and endoscopic therapies for GERD and the new management strategies for BE should dramatically reduce the clinical toll of this disease on society.

The effect of total and anterior partial fundoplication on antireflux mechanisms of the gastroesophageal junction

BACKGROUND

The effect of total (Nissen) and anterior partial fundoplication (APF) for the surgical treatment of gastroesophageal reflux disease (GERD) on the motor behavior of the esophagogastric axis has not been fully assessed. The purpose of this study was to assess any alterations in lower esophageal sphincter (LES) and gastric fundus motor parameters in GERD patients after Nissen or APF fundoplication.

METHODS

Twenty four patients with documented GERD underwent either laparoscopic Nissen fundoplication (n = 12) or laparoscopic APF (n = 12). Preoperative and postoperative stationary esophageal manometry included assessment of LES resting and postdeglutition relaxation pressures, intragastric pressure, and LES transient relaxations in the left lateral and upright positions and after gastric distension.

RESULTS

Both types of fundoplication resulted in significant increases in LES resting (P <0.001) and postdeglutition relaxation pressure (P <0.001) in both positions and after gastric distention. Intragastric pressure increased only after Nissen fundoplication in the postgastric distention state (P = 0.01). Transient LES relaxations were equally abolished after both procedures. All postoperative changes were to a similar level after either procedure with the exception of intragastric pressure after gastric distention, which was significantly higher after total than after partial fundoplication (P = 0.04).

CONCLUSIONS

Both procedures equally increase LES resting and postdeglutition relaxation pressures and abolish transient LES relaxations at all states. The significantly higher intragastric pressure at the postgastric distention state after Nissen fundoplication could possibly explain the higher incidence of epigastric fullness and discomfort after this type of antireflux surgery.

Effect of hyperglycemia on triggering of transient lower esophageal sphincter relaxations

Acute changes in blood glucose concentration have major effects on gastrointestinal motor function. Patients with diabetes mellitus have an increased prevalence of gastroesophageal reflux. Transient lower esophageal sphincter (LES) relaxation (TLESR) is the most common sphincter mechanism underlying reflux. The aim of this study was to investigate the effect of acute hyperglycemia on triggering TLESRs evoked by gastric distension in healthy volunteers. TLESRs were stimulated by pressure-controlled and volume-controlled (500 ml) gastric distension using an electronic barostat and performed on separate days. On each day, esophageal manometry was performed in the sitting position during gastric distension for 1 h under euglycemia (5 mM), and either marked hyperglycemia (15 mM) or physiological hyperglycemia (8 mM) in randomized order was maintained by a glucose clamp. Marked hyperglycemia doubled the rate of TLESRs in response to both pressure-controlled [5 (3-10.5, median or interquartile range) to 10 (9.5-14.5) per hour, P < 0.02] and volume-controlled [4 (2.5-7.5) to 10.5 (7-12.5) per hour, P < 0.02] gastric distension but had no effect on basal LES pressure. Physiological hyperglycemia had no effect on the triggering of TLESRs or basal LES pressure. In healthy human subjects, marked hyperglycemia increases the rate of TLESRs. Increase in the rate of TLESRs is independent of proximal gastric wall tension. Mechanisms underlying the effect remain to be determined. Hyperglycemia may be an important factor contributing to the increased esophageal acid exposure in patients with diabetes mellitus.

Does laparoscopic antireflux surgery prevent the occurrence of transient lower esophageal sphincter relaxation?

BACKGROUND

Transient lower esophageal sphincter relaxation (TLESR) is the most common mechanism underlying gastroesophageal reflux disease (GERD), causing 70% to 100% of the reflux episodes in normal subjects and 63% to 74% of the reflux episodes in patients with reflux disease. This study aimed to evaluate the effect of laparoscopic Nissen fundoplication on TLESR in patients with proven GERD.

METHODS

We prospectively followed 73 consecutive patients (13 men and 60 women; mean age, 43.7 +/- 1.72 years) with proven diagnosis of GERD and reported TLESRs found during a 40-min esophageal manometric study. These patients had repeat testing 6 months after undergoing laparoscopic Nissen fundoplication.

RESULTS

Laparoscopic Nissen fundoplication increased the basal and nadir lower esophageal sphincter (LES) pressure and significantly reduced the number of TLESRs during the manometric study. No patients after surgery exhibited TLESR with nadir less than 2 mmHg. However, 8 of the 73 patients (11%) exhibited TLESR to a nadir exceeding 50% of basal pressure (mean nadir, 5.0 +/- 1.07 mmHg).

CONCLUSIONS

The number of TLESRs is reduced significantly by antireflux surgery. Even accounting for increased basal and nadir pressures, the incidence of TLESR is reduced, suggesting that there may be additional mechanisms involved in this process.