The bitter tastant denatonium benzoate has no influence on the number of transient lower esophageal sphincter relaxations in health

BACKGROUND

Administration of a bitter compound can alter the intragastric pressure (IGP) after a meal. Additionally, a negative correlation between IGP and the number of transient lower esophageal sphincter relaxations (TLESRs) has been demonstrated. However, the effect of a bitter tastant on the number of TLESRs and subsequent reflux episodes has never been investigated and it is unclear whether bitter food items should be avoided in gastro-esophageal reflux disease. We hypothesize that bitter administration in healthy volunteers (HVs) will lead to an increase in the number of TLESRs.

METHODS

After an overnight fast, 20 female HVs (36 years [21-63]) underwent a high-resolution impedance manometry (HRiM) measurement. After placement of the HRiM probe, 0.1 ml/kg of a 10 mM denatonium benzoate solution (bitter) or an identical volume of water (placebo) was administered directly into the stomach. The number of TLESRs and reflux episodes was quantified 30 min before and 2 h after consumption of a high caloric meal.

KEY RESULTS

There was no significant difference in the number of TLESRs or reflux episodes between the bitter and placebo condition. Additionally, no differences were observed in the nature (gas or liquid) and extent of reflux events. Lower esophageal sphincter pressures dropped significantly in the first postprandial hour to start recovering slowly back to baseline values during the second postprandial hour (p < 0.0001), without any difference between both conditions.

CONCLUSIONS & INTERFERENCES

Administration of the bitter tastant denatonium benzoate has no influence on the number of TLESRs or reflux episodes.

Effect of citalopram on esophageal motility in healthy subjects-Implications for reflux episodes, dysphagia, and globus

BACKGROUND

Drugs such as citalopram, "targeting" the serotonin pathway, can alter esophageal mechano-chemical sensitivity and gastrointestinal motility. The aim of this study was to clarify the effect of citalopram on esophageal motility and sphincter function, transient lower esophageal sphincter relaxations (TLESRs), and reflux events.

METHODS

Sixteen healthy volunteers (HV) receiving 20 mg citalopram or placebo intravenously, in a randomized cross-over fashion, underwent two high-resolution impedance manometry studies involving liquid swallows and a high-fat, high-caloric meal. Manometric, reflux, and symptom-related parameters were studied.

KEY RESULTS

A lower distal contractile integral was recorded under citalopram, compared with placebo (P = 0.026). Upper esophageal sphincter (UES) resting pressure was significantly higher after citalopram administration throughout the study (P < 0.05, all periods). Similarly, the UES postswallow mean and maximum pressures were higher in the citalopram condition (P < 0.0001, in both cases) and this was also the case for the 0.2 s integrated relaxation pressure (P = 0.04). Esophagogastric junction resting pressures in the citalopram visit were significantly higher during swallow protocol, preprandial period, and the first postprandial hour (P < 0.05, in all cases). TLESRs and total reflux events were both reduced after citalopram infusion (P = 0.01, in both cases). During treatment with citalopram, five participants complained about globus sensation (P = 0.06). This citalopram-induced globus was associated with higher UES postswallow mean and maximum pressure values (P = 0.01 and P = 0.04, respectively).

CONCLUSIONS AND INFERENCES

Administration of citalopram exerts a diversified response on esophageal motility and sphincter function, linked to clinically relevant phenomena: a reduction in postprandial TLESRs and the induction of drug-induced globus.

24-hour monitoring of transient lower esophageal sphincter relaxation events by long-term high-resolution impedance manometry in normal volunteers: The "mirror phenomenon"

BACKGROUND

The aim of this study was to investigate the frequency and circadian changes in transient lower esophageal sphincter relaxations (TLESRs) in normal volunteers using 24-hour high-resolution impedance manometry (HRIM).

METHODS

Fifteen volunteers underwent HRIM. TLESRs were recorded during the mealtime, 2-hour postprandial, daytime, and supine periods. The catheter was firmly secured to the nose, and subjects went home, ate normal meals, and continued routine daily activities.

KEY RESULTS

Successful recordings were obtained in 11 volunteers. Overall, 1083 TLESRs were documented; the average occurrence was 4.2/h, and the duration was 21.0 ± 5.2 seconds. The majority of the TLESRs occurred during the 2-hour postprandial (42.7%) and daytime (31.5%) periods, while 10.2% and 15.6% occurred during the mealtime and supine periods, respectively. Eight hundred and eighty-six (81.8%) TLESRs were associated with reflux. Overall, 25.5% of TLESRs were preceded by partial secondary peristalsis (PSP), while 74.5% were preceded by nothing. Terminating events included primary peristalsis (PP; 40.3%), PSP (42.8%), full secondary peristalsis (FSP; 8.2%), or nothing (8.7%). Both preceding and terminating events periodically changed throughout the four periods. One hundred and twelve (10.3%) TLESRs with both preceding and terminating events of PSP, presenting as a "mirror phenomenon," were documented. The majority of these TLESRs occurred during the supine (70.5%).

CONCLUSIONS & INFERENCES

Transient lower esophageal sphincter relaxations are common physiological motor events in normal volunteers; these events have certain circadian rhythms, as do the events that precede and terminate TLESR events. A special "mirror phenomenon" is observed when both the preceding and terminating events are PSP.

The gastric accommodation response to meal intake determines the occurrence of transient lower esophageal sphincter relaxations and reflux events in patients with gastro-esophageal reflux disease

BACKGROUND

Gastro-esophageal reflux (GER), the retrograde flow of gastric contents into the esophagus is a physiologic phenomenon, which can evoke symptoms and/or lesions in the esophagus (=gastro-esophageal reflux disease or GERD). Proton pump inhibitors (PPIs) reduce gastric acidity; however, as they are unable to control transient lower esophageal sphincter relaxations (TLESRs), the main mechanism for reflux in GERD, they do not abolish reflux. TLESRs occur predominantly in the postprandial period, and they are believed to be triggered by gastric distention. Gastric accommodation (GA) is the physiologic response to gastric distention and serves to prevent a rise in gastric wall tension during food intake. We aimed to study the relationship between GA and TLESRs, as they both are triggered by gastric distention.

METHODS

We studied 12 GERD patients (average age 37 years [range 18-62], 7m/5f) and nine healthy volunteers (average age 27 years [range 22-36], 2m/7f) using high resolution manometry-impedance measurement before and after a mixed meal challenge. We determined the number of TLESRs (with or without reflux) and measured pre- and postprandial IGP. The change in IGP between the pre- and postprandial period (ΔIGP) is used as surrogate for GA. We also measured LES pressure before and after the meal and calculated the change (ΔLESp).

KEY RESULTS

There were no statistical differences between pre- and postprandial IGP in GERD and healthy volunteers and similarly, there was no significant difference between pre- and postprandial LES pressures in GERD patients and healthy volunteers. The number of TLESRs (with or without reflux) was similar in GERD and healthy volunteers. More importantly, we did observe a negative correlation between ΔIGP and the number of TLESRs, irrespective of whether they were associated with reflux or not, in the GERD patients (without reflux r = -0.67, p = 0.017; with reflux r = -0.81, p = 0.0014). The same observations were found in healthy volunteers, where ΔIGP and the number of TLESRs are significantly inversely correlated (without reflux r = -0.87, p = 0.0045; with reflux r = -0.75, p = 0.021). We could not establish a correlation between ΔLESp and the number of TLESRs, neither in GERD patients nor in healthy volunteers.

CONCLUSIONS & INFERENCES

This is the first study showing a clear negative correlation between ΔIGP and the number of TLESRs, irrespective of whether they were associated with reflux or not, both in GERD patients and in healthy subjects. These results suggest that TLESRs and GA are closely linked, probably through activation of mechanoreceptors involved in triggering of TLESRs.

Central obesity in asymptomatic volunteers is associated with increased intrasphincteric acid reflux and lengthening of the cardiac mucosa

BACKGROUND & AIMS

In the West, a substantial proportion of subjects with adenocarcinoma of the gastric cardia and gastroesophageal junction have no history of reflux. We studied the gastroesophageal junction in asymptomatic volunteers with normal and large waist circumferences (WCs) to determine if central obesity is associated with abnormalities that might predispose individuals to adenocarcinoma.

METHODS

We performed a study of 24 healthy, Helicobacter pylori-negative volunteers with a small WC and 27 with a large WC. Abdominal fat was quantified by magnetic resonance imaging. Jumbo biopsy specimens were taken across the squamocolumnar junction (SCJ). High-resolution pH-metry (12 sensors) and manometry (36 sensors) were performed in upright and supine subjects before and after a meal; the SCJ was visualized fluoroscopically.

RESULTS

The cardiac mucosa was significantly longer in the large WC group (2.5 vs 1.75 mm; P = .008); its length correlated with intra-abdominal (R = 0.35; P = .045) and total abdominal (R = 0.37; P = .034) fat. The SCJ was closer to the upper border of the lower esophageal sphincter (LES) in subjects with a large WC (2.77 vs 3.54 cm; P = .02). There was no evidence of excessive reflux 5 cm above the LES in either group. Gastric acidity extended more proximally within the LES in the large WC group, compared with the upper border (2.65 vs 4.1 cm; P = .027) and peak LES pressure (0.1 cm proximal vs 2.1 cm distal; P = .007). The large WC group had shortening of the LES, attributable to loss of the distal component (total LES length, 3 vs 4.5 cm; P = .043).

CONCLUSIONS

Central obesity is associated with intrasphincteric extension of gastric acid and cardiac mucosal lengthening. The latter might arise through metaplasia of the most distal esophageal squamous epithelium and this process might predispose individuals to adenocarcinoma.

A study of pathophysiological factors associated with gastro-esophageal reflux disease in twins discordant for gastro-esophageal reflux symptoms

BACKGROUND

Differences in lower esophageal sphincter (LES) and peristaltic function and in transient LES relaxations (TLESR) have been described in patients with gastro-esophageal reflux disease (GERD). However, some of these differences may be the result of chronic GERD rather than being an underlying contributory factor.

METHODS

Twins discordant for GERD symptoms, i.e., only one twin had GERD symptoms, underwent standard LES and esophageal body manometry, and then using a sleeve sensor prolonged LES and pH monitoring, 30 min before and 60 min after a 250 mL 1200 kcal lipid meal.

KEY RESULTS

Eight monozygotic and 24 dizygotic female twins were studied. Although there was no difference in preprandial LES pressure (symptomatic 13.2 ± 7.1 mmHg vs asymptomatic 15.1 ± 6.2 mmHg, P = 0.4), LES pressure fell further postprandially in symptomatic twins (LES pressure area under the curve 465 ± 126 vs 331 ± 141 mmHg h, P < 0.01). 12/37 (32%) of acid reflux episodes in symptomatic twins occurred due to low LES pressure or deep inspiration/strain and 0/17 in asymptomatic twins (P = 0.01). There was no difference between symptomatic and asymptomatic twins in: peristaltic amplitude, ineffective esophageal body motility, hiatus hernia prevalence, or LES length. There was also no difference in TLESR frequency preprandially (symptomatic median 1(range 0-2) vs asymptomatic 0(0-2), P = 0.08) or postprandially (2.5(1-8) vs 3(1-6), P = 0.81).

CONCLUSIONS & INFERENCES

Twins with GERD symptoms had lower postprandial LES pressure and given the close genetic link between the twins, it is possible that such differences are caused by GERD. Acid reflux episodes associated with a hypotensive LES were seen in symptomatic, but not in asymptomatic twins.