How reflux causes symptoms: reflux perception in gastroesophageal reflux disease

A SIGE-SINGEM-AIGO technical review on the clinical use of esophageal reflux monitoring

Patients with esophageal symptoms potentially associated with gastroesophageal reflux disease such as heartburn, regurgitation, chest pain, or cough represent one of the most frequent reasons for referral to gastroenterological evaluation. The utility of esophageal reflux monitoring in clinical practice is: (1) to accurately define reflux burden, (2) to segregate patients according to reflux monitoring results as true GERD, reflux hypersensitivity and functional heartburn, and (3) to establish a treatment plan. With this in mind, in the last decade, investigations and technical advances, with the introduction of impedance-pH monitoring and wireless pH capsule, have enhanced our understanding and management of GERD. The following recommendations were discussed and approved after a comprehensive review of the medical literature pertaining to reflux testing techniques and their recent application. This review created under the auspices of the Società Italiana di Gastroenterologia ed Endoscopia Digestiva (SIGE), Società Italiana di Neuro-Gastro-Enterologia e Motilità (SINGEM) and Associazione Italiana Gastroenterologi ed Endoscopisti Digestivi Ospedalieri (AIGO) is intended to help clinicians in applying reflux studies in the most fruitful manner within the context of their patients with esophageal symptoms.

Association of serum gastric inhibitory polypeptide and pancreatic polypeptide levels with prolonged esophageal acid exposure time in refractory gastroesophageal reflux disease

BACKGROUND

Acid exposure time (AET) prolongation plays an important role in the pathogenesis of gastroesophageal reflux disease (GERD). Gastric inhibitory polypeptide (GIP) and pancreatic polypeptide (PP) participate in the regulation of gastric acid secretion, blood glucose and lipid levels, and food intake. In this study, we evaluated the serum GIP and PP levels in refractory GERD patients and analyzed their metabolic and motility characteristics.

METHODS

Seventy-three refractory GERD patients were enrolled in this study from September 2015 to September 2017. We investigated the clinical characteristics, severity, and duration of GERD symptoms. High-resolution manometry and 24 hours impedance-pH monitoring were performed to assess esophageal motility and reflux parameters. The patients were divided into the AET- group (AET <4.2%) and AET+ group (AET >4.2%). GIP and PP levels were determined in all subjects and their associations with other parameters evaluated.

RESULTS

Age and GERDQ score were significantly higher (P < .05) and acid reflux and heartburn more frequent in the AET+ group than in the AET- group. The contraction front velocity was increased in the AET- group, while there was no significant difference in the distal contraction integral, peristalsis interruption, distal latency, or resting pressures of the lower and upper esophageal sphincters between the 2 groups (P > .05). The serum levels of GIP (P = .003) and PP (P = .012) were significantly increased in the AET+ group. Increased GIP and PP levels were associated with abnormal upright AET (correlation coefficients 0.307 and 0.233, P = .008 and P = .047). There was a positive correlation between GIP and triglyceride levels (correlation coefficient 0.279, P = .017).

CONCLUSION

The serum levels of GIP and PP in refractory GERD patients with prolongation of AET are significantly elevated, mainly in the upright position.

Ethnobotanical, phytochemical and therapeutic effects of Myrtus communis L. berries seeds on gastrointestinal tract diseases: a review

Medicinal plants have always had an important place in the therapeutic arsenal of humanity and particularly in the treatment of gastrointestinal tract diseases. Myrtus communis L., known as common myrtle, is native to Southern Europe, North Africa, and Western Asia. The different parts of this plant are used as antiinflammatory, antiulcer, antidiabetic, urinary antiseptic, and to treat the respiratory and digestive systems diseases. For the first time, an exhaustive bibliographic research of the seeds of myrtle berries has been carried out. As a result, it has been found that this plant is very rich in biologically active compounds such as phospholipids, polyunsaturated fatty acids, and phenolic compounds. This has made it effective in the treatment of digestive diseases. In order to emphasize the importance of myrtle berries seeds, this review has been established by discussing its botanical, morphological, phytochemical, ethnomedicinal studies as well as its effect on digestive tract diseases.

Medical Therapy of Gastroesophageal Reflux Disease Beyond Proton Pump Inhibitors: Where Are We Heading?

Proton pump inhibitors (PPI) have greatly improved the treatment of gastroesophageal reflux disease. However, recent investigations have revealed that reflux symptoms persist in a substantial number of patients. Therefore, treatment strategies beyond PPI are urgently required. One such strategy may involve more reliable acid suppression, e.g., with new acid inhibitory drugs. Furthermore, the rapid appearance of an acidic compartment in the proximal stomach after a meal, which is largely responsible for postprandial heartburn, requires a specific kind of therapy in addition to PPI which still needs to be established. Pharmacological augmentation of the lower esophageal sphincter may represent another approach to diminish reflux, but the clinical efficacy of compounds tested so far is limited. Altered e-sophageal perception represents a major component involved in the generation of reflux symptoms, particularly in non-erosive reflux disease, but effective pharmacological intervention is largely lacking. Presumed reflux-induced respiratory symptoms (cough, laryngitis, etc.) in the absence of typical esophageal symptoms (e.g., heartburn) remain a hot topic, but recent research points towards a hypersensitivity syndrome and only a minor role of gastroesophageal reflux. Treatment options for this condition are still pending.

Protective effects of Artemisia campestris extract against gastric acid reflux-induced esophageal mucosa injuries

Artemisia campestris L. has been widely used in alternative medicine to treat digestive system diseases, particularly gastroesophageal disorders. In the present investigation, we studied the putative protective effect of Artemisia campestris aqueous extract (ACAE) against gastro-esophageal reflux (GER)-induced esophagitis in rats. The experimental ophagitis was induced by the ligation of the pylorus as well as the junction between the forestomach and the corpus. We firstly found that ACAE administration at 100, 200 and 400 mg/kg, b.w., p.o. significantly protected GER-induced macroscopic and histological injuries in the esophagus tissue. Our extract also counteracted GER-induced esophagus lipoperoxidation, restored the depletion of antioxidant enzyme activities such as superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) as well as thiol groups levels. Furthermore, we showed that acute GER provoked an increase in esophagus mucosa hydrogen peroxide (H₂O₂), free iron and calcium levels, whereas ACAE treatment reversed all GER-induced intracellular mediators' disturbances. In conclusion, we suggested that ACAE had potent protective effects against esophagitis due, in part, to its antioxidant properties as well as its opposite effect on some intracellular mediators.

The Relationship of the Post-reflux Swallow-induced Peristaltic Wave Index and Esophageal Baseline Impedance with Gastroesophageal Reflux Disease Symptoms

Background/Aims

The post-reflux swallow-induced peristaltic wave (PSPW) index and esophageal baseline impedance (BI) are novel impedance parameters used to evaluate esophageal chemical clearance and mucosal integrity. However, their relationship with reflux symptoms is not known. We aim to evaluate the correlations of PSPW index and esophageal BI with gastroesophageal reflux disease (GERD) symptoms.

Methods

We performed a retrospective review of multichannel intraluminal impedance and pH (MII-pH) tracings in patients with suspected GERD. Reflux symptoms were also analyzed from checklists using ordinal scales. The PSPW index and esophageal BIs in 6 spots (z1–z6) were measured. Bivariate (Spearman) correlation was used to analyze the relationship between the PSPW index or esophageal BI, and the degree of GERD symptoms measured.

Results

The MII-pH records of 143 patients were analyzed. The PSPW index was significantly lower in patients who had heartburn and negatively correlated with the degree of heartburn (r = −0.186, P < 0.05). On the contrary, the PSPW index was not significantly correlated with the degree of dysphagia (r = −0.013, P = 0.874). Distal esophageal BI was not significantly correlated with heartburn, but negatively correlated with the degree of dysphagia (z3: r = −0.328, z4: r = −0.361, z5: r = −0.316, z6: r = −0.273; P < 0.05).

Conclusions

These findings suggest that delayed chemical clearance of the esophagus may induce heartburn, but that it is not related to dysphagia. However, a lack of esophageal mucosal integrity may be related to dysphagia.

Practice guidelines on the use of esophageal manometry - A GISMAD-SIGE-AIGO medical position statement

Patients with esophageal symptoms potentially associated to esophageal motor disorders such as dysphagia, chest pain, heartburn and regurgitation, represent one of the most frequent reasons for referral to gastroenterological evaluation. The utility of esophageal manometry in clinical practice is: (1) to accurately define esophageal motor function, (2) to identify abnormal motor function, and (3) to establish a treatment plan based on motor abnormalities. With this in mind, in the last decade, investigations and technical advances, with the introduction of high-resolution esophageal manometry, have enhanced our understanding and management of esophageal motility disorders. The following recommendations were developed to assist physicians in the appropriate use of esophageal manometry in modern patient care. They were discussed and approved after a comprehensive review of the medical literature pertaining to manometric techniques and their recent application. This position statement created under the auspices of the Gruppo Italiano di Studio per la Motilità dell'Apparato Digerente (GISMAD), Società Italiana di Gastroenterologia ed Endoscopia Digestiva (SIGE) and Associazione Italiana Gastroenterologi ed Endoscopisti Digestivi Ospedalieri (AIGO) is intended to help clinicians in applying manometric studies in the most fruitful manner within the context of their patients with esophageal symptoms.

Mucosal integrity and sensitivity to acid in the proximal esophagus in patients with gastroesophageal reflux disease

Acid reflux episodes that extend to the proximal esophagus are more likely to be perceived. This suggests that the proximal esophagus is more sensitive to acid than the distal esophagus, which could be caused by impaired mucosal integrity in the proximal esophagus. Our aim was to explore sensitivity to acid and mucosal integrity in different segments of the esophagus. We used a prospective observational study, including 12 patients with gastroesophageal reflux disease (GERD). After stopping acid secretion-inhibiting medication, two procedures were performed: an acid perfusion test and an upper endoscopy with electrical tissue impedance spectroscopy and esophageal biopsies. Proximal and distal sensitivity to acid and tissue impedance were measured in vivo, and mucosal permeability and epithelial intercellular spaces at different esophageal levels were measured in vitro. Mean lag time to heartburn perception was much shorter after proximal acid perfusion (0.8 min) than after distal acid perfusion (3.9 min) (P = 0.02). Median in vivo tissue impedance was significantly lower in the distal esophagus (4,563 Ω·m) compared with the proximal esophagus (8,170 Ω·m) (P = 0.002). Transepithelial permeability, as measured by the median fluorescein flux was significantly higher in the distal (2,051 nmol·cm(-2)·h(-1)) than in the proximal segment (368 nmol·cm(-2)·h(-1)) (P = 0.033). Intercellular space ratio and maximum heartburn intensity were not significantly different between the proximal and distal esophagus. In GERD patients off acid secretion-inhibiting medication, acid exposure in the proximal segment of the esophagus provokes symptoms earlier than acid exposure in the distal esophagus, whereas mucosal integrity is impaired more in the distal esophagus. These findings indicate that the enhanced sensitivity to proximal reflux episodes is not explained by increased mucosal permeability.

Protease-Activated Receptor-2 Up-Regulates Transient Receptor Potential Vanilloid 4 Function in Mouse Esophageal Keratinocyte

BACKGROUND

The reflux of pancreatic-duodenal fluids is implicated in the pathophysiology of proton-pump inhibitor-resistant gastroesophageal reflux disease (GERD). Protease-activated receptor-2 (PAR-2) is activated by proteases, the pancreatic enzyme, trypsin, and the activated PAR-2 enhances transient receptor potential vanilloid 4 (TRPV4) function in neurons. TRPV4 stimulates ATP exocytosis in conjunction with the vesicular nucleotide transporter, which mediates mechano-transduction and vagal stimulation. The aim of the present study was to verify whether the activated PAR-2 up-regulates TRPV4 function in mouse esophageal keratinocytes, which may link to the pathophysiology in PPI-resistant GERD.

METHODS

TRPV4 and PAR-2 expressions were detected by RT-PCR, immunostaining, and western blotting in mouse esophageal keratinocytes. The functional response of TRPV4 to esophageal keratinocytes was analyzed using a Ca(2+) imaging system. Cellular ATP release was examined by luciferase-luciferin reaction. TRPV4 phosphorylation was studied by immunoprecipitation and western blotting.

RESULTS

PAR-2 and TRPV4 mRNAs and proteins were expressed in esophageal keratinocytes. Pre-treatment with trypsin significantly increased the responses to TRPV4 activator in esophageal keratinocytes, probably via the phosphorylation of serine residue of TRPV4 by protein kinase C and resulted in cellular ATP release from the cells.

CONCLUSIONS

Activated PAR-2 with trypsin exposure up-regulated TRPV4 function and increased ATP release in mouse esophageal keratinocytes. This mechanism might be related to the pathophysiology of GERD, especially non-erosive GERD.

Pathophysiology of gastroesophageal reflux disease: new understanding in a new era

BACKGROUND

The prevalence of gastroesophageal reflux disease (GERD) has increased in the last decades and it is now one of the most common chronic diseases. Throughout time our insight in the pathophysiology of GERD has been characterized by remarkable back and forth swings, often prompted by new investigational techniques. Even today, the pathophysiology of GERD is not fully understood but it is now recognized to be a multifactorial disease. Among the factors that have been shown to be involved in the provocation or increase of reflux, are sliding hiatus hernia, low lower esophageal sphincter pressure, transient lower esophageal sphincter relaxation, the acid pocket, obesity, increased distensibility of the esophagogastric junction, prolonged esophageal clearance, and delayed gastric emptying. Moreover, multiple mechanisms influence the perception of GERD symptoms, such as the acidity of the refluxate, its proximal extent, the presence of gas in the refluxate, duodenogastroesophageal reflux, longitudinal muscle contraction, mucosal integrity, and peripheral and central sensitization. Understanding the pathophysiology of GERD is important for future targets for therapy as proton pump inhibitor-refractory GERD symptoms remain a common problem.

PURPOSE

In this review we provide an overview of the mechanisms leading to reflux and the factors influencing perception, in the light of historical developments. It is clear that further research remains necessary despite the recent advances in the understanding of the pathophysiology of GERD.

Patients with refractory reflux symptoms often do not have GERD

BACKGROUND

In patients with typical reflux symptoms that persist despite proton pump inhibitors (PPIs) it is sometimes overlooked that treatment fails due to the presence of other disorders than gastroesophageal reflux disease (GERD). The aim of this study was to determine the underlying cause of reflux symptoms not responding to PPI therapy in tertiary referral patients.

METHODS

Patients with reflux symptoms refractory to PPI therapy who underwent 24-h pH-impedance monitoring were analyzed. Patients in whom a diagnosis was already established before referral, who had previous esophageal or gastric surgery, or who had abnormalities on gastroscopy other than hiatus hernia, were excluded.

KEY RESULTS

In total, 106 patients were included. Esophageal manometry showed achalasia in two patients and distal esophageal spasm in another two. Twenty-four-hour pH-impedance monitoring revealed a total acid exposure time <6% in 60 patients (56.6%) of which 25 had a positive symptom association probability (SAP) while 35 showed a negative SAP. Sixty-nine patients ended up with a final diagnosis of GERD while 32 patients (30.2%) were diagnosed with functional heartburn (FH), two with functional chest pain, two with achalasia, and one with rumination. A trend toward an association with a final diagnosis of FH was found with the atypical symptom epigastric pain (p = 0.059) and with a secondary diagnosis of functional dyspepsia (p = 0.083).

CONCLUSIONS & INFERENCES

Approximately one-third of the patients referred with refractory reflux symptoms suffer from disorders other than GERD, predominantly FH. This explains, at least partly, why many patients will not benefit from acid inhibitory treatment.

Farnesoid X receptor signal is involved in deoxycholic acid-induced intestinal metaplasia of normal human gastric epithelial cells

The farnesoid X receptor (FXR) signaling pathway is known to be involved in the metabolism of bile acid, glucose and lipid. In the present study, we demonstrated that 400 µmol/l deoxycholic acid (DCA) stimulation promotes the proliferation of normal human gastric epithelial cells (GES-1). In addition, DCA activated FXR and increased the expression of intestinal metaplasia genes, including caudal-related homeobox transcription factor 2 (Cdx2) and mucin 2 (MUC2). The treatment of FXR agonist GW4064/antagonist guggulsterone (Gug.) significantly increased/decreased the expression levels of FXR, Cdx2 and MUC2 protein in DCA-induced GES-1 cells. GW4064/Gug. also enhanced/reduced the nuclear factor-κB (NF-κB) activity and binding of the Cdx2 promoter region and NF-κB, the most common subunit p50 protein. Taken together, the results indicated that DCA is capable of modulating the expression of Cdx2 and the downstream MUC2 via the nuclear receptor FXR-NF-κB activity in normal gastric epithelial cells. FXR signaling pathway may therefore be involved in the intestinal metaplasia of human gastric mucosa.

Predictive value of routine esophageal high-resolution manometry for gastro-esophageal reflux disease

BACKGROUND

Using conventional manometry, gastro-esophageal reflux disease (GERD) was associated with a reduced lower esophageal sphincter (LES) pressure and impaired peristalsis. However, with a large overlap between GERD patients and controls, these findings are of limited clinical relevance. It is uncertain whether the more detailed information of high-resolution manometry (HRM) can discriminate GERD patients. Therefore, we aimed to determine to which extent HRM findings can predict GERD.

METHODS

HRM measurements in 69 patients with GERD and 40 healthy subjects were compared and the predictive value of HRM for the diagnosis of GERD was explored.

KEY RESULTS

GERD patients had a significantly lower contraction amplitude (55 vs 64 mmHg; p = 0.045) and basal LES pressure (10 vs 13.2 mmHg; p = 0.034) than healthy controls. GERD patients more often had a hiatal hernia than healthy subjects (30% vs 7%; p = 0.005). Patients with reflux esophagitis had a lower DCI than patients without reflux esophagitis (558 vs 782 mmHg cm s; p = 0.045). No significant difference was seen in contractile front velocity, distal latency, number of peristaltic breaks, residual LES pressure and LES length. On multivariate logistic regression analysis, both esophagogastric junction type I (OR 4.971; 95% CI 1.33-18.59; p = 0.017) and mean wave amplitude (OR 0.95; 95% CI 0.90-0.98; p = 0.013) were found to be independent predictors of GERD. However, the sensitivity and specificity of these findings were low.

CONCLUSIONS & INFERENCES

Hiatal hernia, low contraction amplitude and LES pressure are associated with GERD, but do not predict the disease with sufficient accuracy. Routine esophageal HRM can therefore not be used to distinguish GERD patients from healthy subjects.

Does Measurement of Esophagogastric Junction Distensibility by EndoFLIP Predict Therapy- responsiveness to Endoluminal Fundoplication in Patients With Gastroesophageal Reflux Disease?

Background/Aims

In patients with gastroesophageal reflux disease (GERD), an increased esophagogastric junction (EGJ) distensibility has been described. Assessment of EGJ distensibility with the endoscopic functional luminal imaging probe (EndoFLIP) technique might identify patients responsive to transoral incisionless fundoplication (TIF), whereas postoperative measurement of EGJ distensibility might provide insight into the antireflux mechanism of TIF. Therefore, we investigated the value of the EndoFLIP technique in GERD patients treated by TIF.

Methods

Forty-two GERD patients underwent EGJ distensibility measurement before TIF using the EndoFLIP technique. In a subgroup of 25 patients, EndoFLIP measurement was repeated both postoperative and at 6 months follow-up. Treatment outcome was assessed according to esophageal acid exposure time (AET; objective outcome) and symptom scores (clinical outcome) 6 months after TIF.

Results

Multiple logistic regression analysis showed that preoperative EGJ distensibility (OR, 0.16; 95% CI, 0.03–0.78; P = 0.023) and preoperative AET (OR, 0.62; 95% CI, 0.42–0.90; P = 0.013) were independent predictors for objective treatment outcome but not for clinical outcome after TIF. The best cut-off value for objective outcome was 2.3 mm²/mmHg for preoperative EGJ distensibility and 11% for preoperative AET. EGJ distensibility decreased direct postoperative from 2.0 (1.2–3.3) to 1.4 (1.0–2.2) mm²/mmHg (P = 0.014), but increased to 2.2 (1.5–3.0) at 6 months follow-up (P = 0.925, compared to preoperative).

Conclusions

Preoperative EGJ distensibility and preoperative AET were independent predictors for objective treatment outcome but not for clinical outcome after TIF. According to our data, the EndoFLIP technique has no added value either in the preoperative diagnostic work-up or in the post-procedure evaluation of endoluminal antireflux therapy.

Effect of laparoscopic antireflux surgery on esophageal motility

BACKGROUND/AIMS

The effect of laparoscopic antireflux surgery on esophageal motility is incompletely understood, and any indication for this procedure in patients with motility disorder is disputed in literature. We evaluated the influence of laparoscopic Nissen fundoplication on impaired esophageal motility.

METHODS

In this pathological manometric study, we divided the patients into two groups preoperatively: the hypomotility group (mean amplitude of esophageal contraction wave <40 mm Hg; HYPO group, n = 11) and the normal group (mean amplitude of esophageal contraction wave >40 mm Hg; NORM group, n = 43). The amplitudes of esophageal contraction waves 3 and 8 cm above the lower esophageal sphincter and the percentage of peristaltic contraction waves of the tubular esophagus were analyzed pre- and postoperatively.

RESULTS

In total, 54 patients with GERD underwent esophageal manometry before and 6 months after Nissen fundoplication. The length and pressure of the lower esophageal sphincter were increased in both groups postoperatively (p < 0.01). Patients in the HYPO group (n = 11) showed a statistically significant increase of mean amplitude of esophageal contraction (32.8 vs. 57.3 mm Hg; p < 0.01), while no change was found in the NORM group (n = 43). A total of 72% of patients with preoperative motility disorder showed normal postoperative manometry.

CONCLUSION

Nissen fundoplication normalizes esophageal motility, especially in patients with preoperative hypomotility. Patients with impaired esophageal motility should not per se be excluded from antireflux surgery.

Pathophysiology of gastroesophageal reflux disease

Gastroesophageal reflux disease (GERD) is one of the most common digestive diseases in the Western world, with typical symptoms, such as heartburn, regurgitation, or retrosternal pain, reported by 15% to 20% of the general population. The pathophysiology of GERD is multifactorial. Our understanding of these factors has significantly improved in recent years, with increased understanding of the acid pocket and hiatal hernia and how these factors interact. Although our insight has significantly increased over the past years, more studies are required to better understand symptom generation in GERD, especially in patients with therapy-resistant symptoms.