Duodenal lipid-induced symptom generation in gastroesophageal reflux disease: role of apolipoprotein A-IV and cholecystokinin

Vegetal and Animal Food Proteins Have a Different Impact in the First Postprandial Hour of Impedance-pH Analysis in Patients with Heartburn

Background and Aims

By means of 24 h impedance-pH monitoring, we aimed to evaluate the effect of two different meals with a bromatological balanced composition: one with a prevailing component of animal proteins and the other with vegetable proteins.

Patients and Methods

We enrolled 165 patients with heartburn and negative endoscopy, who underwent impedance-pH monitoring off therapy. Patients were allocated to receive a Mediterranean diet with a total caloric intake of about 1694 kcal, divided into two meals: one with a prevailing component of animal proteins and the other with vegetable proteins. We evaluated the total reflux number, acid exposure time (AET), and symptom-reflux association with impedance-pH analysis. Moreover, during the first postprandial hour (at lunch and dinner), we evaluated the total reflux number, number of acid and weakly acidic refluxes, AET, and presence of symptoms.

Results

The male/female ratio was 80/85. Mean age was 51.9 ± 12.1 years. Impedance-pH analysis showed that 55/165 patients had pathological AET or a number of refluxes (nonerosive reflux disease (NERD)), 49/165 had normal AET and a number of refluxes but positive symptom-reflux association (hypersensitive esophagus (HE)), and 61/165 had normal AET and a number of refluxes with negative symptom-reflux association (functional heartburn (FH)). The overall first postprandial hour analysis showed a higher total reflux number, acid reflux number, and AET after the animal protein meal than after the vegetable protein meal. Moreover, more symptoms were reported after the animal protein meal. Similar results have been observed in the three different subcategories of patients (NERD, HE, and FH).

Conclusions

Vegetable proteins are associated with a lower number of refluxes, particularly acid refluxes, and with a reduced number of symptoms during the first postprandial hour. This is a pilot study and future investigations are warranted to confirm these results.

Functional dyspepsia patients have lower mucosal cholecystokinin concentrations in response to duodenal lipid

BACKGROUND

Dyspeptic symptoms are frequently induced, or exacerbated, by fatty food ingestion. Excessive release of, and/or hypersensitivity to, cholecystokinin (CCK) may explain the exaggerated response to lipid in patients with functional dyspepsia (FD). Thus far, plasma CCK response has been evaluated. However, stimulation of CCK1 receptors on duodenal vagal afferents occurs in a paracrine manner, suggesting that mucosal CCK concentrations are relevant to quantify. Apolipoprotein A-IV stimulates mucosal CCK release.

AIM

To investigate the hypothesis that fat-induced release of CCK and apolipoprotein A-IV (apoA-IV) is enhanced in the duodenum of FD patients.

PATIENTS AND METHODS

Sixteen symptomatic FD patients and 10 healthy volunteers (HV) underwent duodenal perfusion with intralipid 20%, 2 kcal/min, for 60 min. Symptoms were scored and blood samples were collected every 15 min during lipid perfusion and 15 min after discontinuation when duodenal biopsies were taken. Plasma and mucosal concentrations of CCK and apoA-IV were quantified.

RESULTS

Abdominal discomfort (P=0.001), nausea (P=0.05), and fullness (P=0.005) in response to duodenal lipid increased significantly only in FD patients. Following lipid infusion, the mean mucosal CCK concentration was lower in FD patients compared with HV (P<0.0001). Fasting concentrations and plasma response of CCK were comparable in FD patients and HV. Plasma apoA-IV response appeared to differ between patients and HV, whereas mucosal apoA-IV concentrations were similar.

CONCLUSION

Our results suggest excessive local release of CCK in response to duodenal lipid in FD. This likely causes exaggerated stimulation of duodenal vagal afferents, explaining dyspeptic symptom generation. The mechanisms underlying elevated mucosal CCK release warrant further investigation.

Dietary lipids and functional gastrointestinal disorders

There is convincing evidence that patients with functional gastrointestinal disorders (FGIDs) exhibit dysfunctions of the gut involving hypersensitivity and abnormal reflexes, so that physiological, normally unperceived, stimuli induce symptoms. The type of symptoms depends on the specific sensory-reflex pathways and region(s) affected. Fat modulates the responses of the gut to various stimuli, and some of these modulatory mechanisms are abnormal in patients with FGIDs. Indeed, laboratory-based studies have shown that the symptoms experienced by these patients can be induced, or exacerbated, by administration of lipids in amounts that are well tolerated by healthy controls, and, thus, demonstrate a hypersensitivity to lipid. Very few studies have evaluated dietary patterns and eating behavior in these patients, with often-conflicting outcomes, and no studies have been performed to evaluate the role of targeted dietary interventions for the relief of symptoms. Given the evidence from laboratory studies, as well as patient experience, such studies, in large cohorts of patients, are needed with the view to develop personalized, cost-effective treatment approaches.

Recent progress in research of gastroesophageal reflux disease: Pathogenesis, diagnosis and treatment

The incidence of gastroesophageal reflux disease has been increasing annually in China. The emergence of new techniques in recent years has not only facilitated the diagnosis of this complex disease but also improved the understanding of the pathogenesis of this disease. Nowadays much attention is paid to adverse reactions of drugs such as proton pump inhibitors and prokinetic agents for gastroesophageal reflux disease, which has promoted the development of new treatments for gastroesophageal reflux disease. In this review, we will summarize recent progress in research of gastroesophageal reflux disease in terms of its pathogenesis, diagnosis and treatment.