Redefining gastroesophageal reflux (GER)

The effects of exogenous lipid on THP-1 cells: an in vitro model of airway aspiration?

Chronic inflammatory diseases of the airways are associated with gastro-oesophageal reflux (GOR) and aspiration events. The observation of lipid-laden macrophages (LLMs) within the airway may indicate aspiration secondary to GOR. The proposed mechanism, that lipid droplets from undigested or partially digested food are aspirated leading to accumulation in scavenging macrophages, led us to hypothesise that an activated population of LLMs could interact with other immune cells to induce bronchial inflammation. To test this, we generated an in vitro model using differentiated THP-1 cells, which were treated with a high-fat liquid feed. Here, we show that THP-1 cells can take up lipid from the high-fat feed independent of actin polymerisation or CD36-dependent phagocytosis. These cells did not exhibit M1 or M2 polarisation. Gene array analysis confirmed over 8000 genes were upregulated by at least twofold following high fat exposure, and IL-8 was the most upregulated gene. Pathway analysis revealed upregulation of genes known to be involved in chronic obstructive pulmonary disease (COPD) pathophysiology. We suggest that aspiration and macrophage phagocytosis may be important mechanisms in the aetiology of diseases such as COPD and cystic fibrosis that are characterised by high levels of IL-8 within the airways.

Liquid-containing Refluxes and Acid Refluxes May Be Less Frequent in the Japanese Population Than in Other Populations: Normal Values of 24- hour Esophageal Impedance and pH Monitoring

Background/Aims

Twenty-four-hour esophageal impedance and pH monitoring allows detection of all types of reflux episodes and is considered the best technique for identifying gastroesophageal refluxes. However, normative data for the Japanese population are lacking. This multicenter study aimed to establish the normal range of 24-hour esophageal impedance and pH data both in the distal and the proximal esophagus in Japanese subjects.

Methods

Forty-two healthy volunteers (25 men and 17 women) with a mean ± standard deviation age of 33.3 ± 12.4 years (range: 22–72 years) underwent a combined 24-hour esophageal impedance and pH monitoring. According to the physical and pH properties, distal or proximal esophageal reflux events were categorized.

Results

Median 45 reflux events occurred in 24 hours, and the 95th percentile was 85 events. Unlike previous reports, liquid-containing reflux events are median 25/24 hours with the 95th percentile of 62/24 hours. Acidic reflux events were median 11/24 hours with the 95th percentile of 39/24 hours. Non-acidic gas reflux events were median 15/24 hours with the 95th percentile of 39/24 hours. Proximal reflux events accounted for 80% of the total reflux events and were mainly non-acidic gas refluxes. About 19% of liquid and mixed refluxes reached the proximal esophagus.

Conclusions

Unlike previous studies, liquid-containing and acidic reflux events may be less frequent in the Japanese population. Non-acidic gas reflux events may be frequent and a cause of frequent proximal reflux events. This study provides important normative data for 24-hour impedance and pH monitoring in both the distal and the proximal esophagus in the Japanese population.

Surgical management of gastroesophageal reflux disease

Antireflux surgery has become a well-established therapy for gastroesophageal reflux disease (GERD) and its complications. The popularization of minimally invasive surgical techniques has brought about a revolution in the use of fundoplication for the long-term management of GERD. A reliable and objective understanding of the outcomes following fundoplication is important for all physicians treating GERD, so that informed decisions can be made regarding the optimal treatment strategy for a given patient. With ongoing study, the appropriate indications for surgical intervention among the array of potential antireflux therapies will continue to be elucidated.

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.

Critical analysis of esophageal multichannel intraluminal impedance monitoring 20 years later

Multichannel intraluminal impedance (MII) for the evaluation of esophageal diseases was created in 1991 trying to solve previous limitations of esophageal function test. MII-pH is able to determine the physical characteristics of the refluxate (liquid, gas, or mixed) and nonacidic GER. MII-manometry can determine the presence of bolus and its relation with peristalsis. This paper makes a critical analysis of the clinical applications of MII 20 years after its creation. Literature review shows that MII made great contributions for the understanding of esophageal physiology; however, direct clinical applications are few. MII-pH was expected to identify patients with normal acid reflux and abnormal nonacidic reflux. These patients are rarely found off therapy, that is, nonacidic reflux parallels acid reflux. Furthermore, the significance of isolated nonacidic reflux is unclear. Contradictory MII-manometry and conventional manometry findings lack better understanding and clinical implication as well as the real significance of bolus transit.

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.

Evaluating outcomes of endoscopic full-thickness plication for gastroesophageal reflux disease (GERD) with impedance monitoring

BACKGROUND

Endoscopic full-thickness plication allows transmural suturing at the gastroesophageal junction to recreate the antireflux barrier. Multichannel intraluminal impedance monitoring (MII) can be used to detect nonacid or weakly acidic reflux, acidic swallows, and esophageal clearance time. This study used MII to evaluate the outcome of endoscopic full-thickness plication.

METHODS

In this study, 12 subsequent patients requiring maintenance proton pump inhibitor therapy underwent endoscopic full-thickness plication for treatment of gastroesophageal reflux disease. With patients off medication, MII was performed before and 6-months after endoscopic full-thickness plication.

RESULTS

The total median number of reflux episodes was significantly reduced from 105 to 64 (p = 0.016). The median number of acid reflux episodes decreased from 73 to 43 (p = 0.016). Nonacid reflux episodes decreased from 23 to 21 (p = 0.306). The median bolus clearance time was 12 s before treatment and 11 s at 6 months (p = 0.798). The median acid exposure time was reduced from 6.8% to 3.4% (p = 0.008), and the DeMeester scores were reduced from 19 to 12 (p = 0.008).

CONCLUSION

Endoscopic full-thickness plication significantly reduced total reflux episodes, acid reflux episodes, and total reflux exposure time. The DeMeester scores and total acid exposure time for the distal esophagus were significantly improved. No significant changes in nonacid reflux episodes and median bolus clearance time were encountered.

From sponges to capsules. The history of esophageal pH monitoring

The understanding of digestive physiology, gastric acid production, and gastroesophageal reflux disease has been evolving since the 16th century. During this time, several methods to detect gastric refluxate were ingeniously developed. Ambulatory esophageal pH monitoring is still the current gold standard test for the diagnosis of gastroesophageal reflux disease. State-of-the-art technologies use catheter-free wireless pH sensors, an idea first conceived in the 1950s. The authors reviewed the history of esophageal pH monitoring.

Gastroesophageal Reflux Disease, Acid Suppression, and Mycobacterium avium Complex Pulmonary Disease

BACKGROUND

Weekly symptoms of gastroesophageal reflux disease (GERD) occur in 20% of the population, and GERD has been implicated in the pathophysiology of many respiratory diseases. Microaspiration of contaminated water is a potential portal of entry for Mycobacterium avium complex (MAC) organisms into the respiratory tract, and acid-suppression therapy may enhance the survival of mycobacteria in the stomach. This study aimed to assess the prevalence of GERD, swallowing disorders, reflux symptoms, and acid-suppression therapy in patients with MAC lung disease (MAC positive [MAC+]), and to compare these patients to control subjects without MAC lung disease (MAC negative [MAC-]).

METHODS

Clinical information was collected on 58 MAC+ patients and 58 age- and sex-matched MAC- patients who were asked to complete a DeMeester questionnaire of reflux symptoms and to identify any acid-suppressive medication consumed.

RESULTS

A clinical diagnosis of GERD was documented in 23 of 52 MAC+ patients (44.2%), compared to 16 MAC- patients (27.6%) [p = 0.019]. MAC+ patients consumed significantly more histamine type 2 receptor antagonists and prokinetic agents, and MAC- patients consumed more antacids. The mean DeMeester questionnaire score (+/- SD) for MAC+ patients was 1.39 +/- 1.8, and for MAC- patients was 0.88 +/- 1.4. (p = 0.098). Aspiration was suspected in nine MAC+ patients (15.5%), compared to three MAC- patients (5.2%) [p = 0.032]. There was no association between GERD and radiologic presentation of MAC disease. Consolidation and nodules > 5 mm were more common in those receiving acid suppression than those who were not.

CONCLUSIONS

GERD, acid suppression, and clinically suspected aspiration are more common in patients with MAC lung disease than in similar patients without MAC disease.

Evaluation of esophageal function for antireflux surgery

Antireflux surgery has become well established as an effective and durable therapy for gastroesophageal reflux disease and its complications. The outcome of antireflux surgery, however, is only as good as the evaluation to document the association between pathologic esophageal acid exposure and the patient's symptoms. This article discusses the well-established diagnostic modalities used to assess foregut structure and function and includes several more sophisticated secondary studies that may aid the clinician in elucidating the cause of the problem in patients in whom standard testing is inadequate.

Review article: gastro-oesophageal reflux disease -- how wide is its span?

Symptoms of gastro-oesophageal reflux disease are highly prevalent in Western countries; however, it is less certain how many individuals with heartburn have clinically relevant disease. Although the prevalence of gastro-oesophageal reflux disease in Asia is substantially lower, the incidence may be increasing. How much of this increase is explained by the increasing recognition of heartburn in clinical practice, dietary changes and increasing obesity, or the eradication of Helicobacter pylori, remains unclear. There has been speculation that endoscopy-negative reflux disease represents a separate entity from reflux oesophagitis (as defined by the Los Angeles classification), but the evidence that might support this proposal is unconvincing. Patients with chronic reflux symptoms have a higher risk of Barrett's oesophagus, and the increased risk of developing oesophageal adenocarcinoma in individuals with a long history of heartburn is also well documented, but whether this always occurs via Barrett's oesophagus is debatable. Moreover, treatment with standard-dose antisecretory therapies and anti-reflux surgery seems unlikely, based on current evidence, to reduce the cancer risk in patients with Barrett's oesophagus. Gastro-oesophageal reflux disease has also been implicated in an increasing array of other conditions, but arguably in these settings it is often over-diagnosed.