Comparable effects of capsaicin-containing red pepper sauce and hydrochloric acid on secondary peristalsis in humans

The effects of simulated gastroesophageal reflux on infant pig oropharyngeal feeding physiology

The neural connectivity among the oral cavity, pharynx, and esophagus is a critical component of infant feeding physiology. Central integration of oral and pharyngeal afferents alters motor outputs to structures that power swallowing, but the potential effects of esophageal afferents on preesophageal feeding physiology are unclear. These effects may explain the prevalence of oropharyngeal dysphagia in infants suffering from gastroesophageal reflux (GER), though the mechanism underlying this relationship remains unknown. Here we use the validated infant pig model to assess the impacts of simulated GER on preesophageal feeding parameters. We used high-speed videofluoroscopy and electromyography to record bottle-feeding before and following the infusion of a capsaicin-containing solution into the lower esophagus. Sucking parameters were minimally affected by capsaicin exposure, such that genioglossus activity was unchanged and tongue kinematics were largely unaffected. Aspects of the pharyngeal swallow were altered with simulated GER, including increased thyrohyoid muscle activity, increased excursions of the hyoid and thyroid per swallow, decreased swallow frequency, and increased bolus sizes. These results suggest that esophageal afferents can elicit changes in pharyngeal swallowing. In addition, decreased swallowing frequency may be the mechanism by which esophageal pathologies induce oropharyngeal dysphagia. Although recent work indicates that oral or pharyngeal capsaicin may improve dysphagia symptoms, the decreased performance following esophageal capsaicin exposure highlights the importance of designing sensory interventions based upon neurophysiology and the mechanisms underlying disordered feeding. This mechanistic approach requires comprehensive data collection across the entirety of the feeding process, which can be achieved using models such as the infant pig.NEW & NOTEWORTHY Simulated gastroesophageal reflux (GER) in an infant pig model resulted in significant changes in pharyngeal swallowing, which suggests that esophageal afferents are centrally integrated to alter motor outputs to the pharynx. In addition, decreased swallow frequency and increased bolus sizes may be underlying mechanisms by which esophageal pathologies induce oropharyngeal dysphagia. The infant pig model used here allows for a mechanistic approach, which can facilitate the design of intervention strategies based on neurophysiology.

Effects of esophageal acid infusion vs mosapride on distension-induced secondary peristalsis in humans

Secondary peristalsis contributes to the clearance of the refluxate from the esophagus. Acute administration of 5-hydroxytryptamine 4 (5-HT₄ ) receptors agonist, mosapride or esophageal infusion of hydrochloric acid (HCl) facilitates secondary peristalsis. The aim of this study was to determine whether esophageal acid infusion and administration of mosapride had different effects on secondary peristalsis. Secondary peristalsis was performed with esophageal distension with rapid and slow air injections in 16 healthy subjects. We performed two separate sessions with HCl (0.1 N) and 40 mg oral mosapride to compare their influence on secondary peristaltic parameters. The threshold volume of secondary peristalsis was significantly lower with HCl infusion than mosapride (P = 0.01) by slow air injections. The threshold volume to generate secondary peristalsis was significantly lower with HCl infusion than mosapride (P = 0.002) by rapid air injections. More secondary peristalsis was trigged by rapid air injections after HCl infusion than mosapride (P = 0.003). Infusion of HCl or mosapride administration has similar effects on peristaltic wave amplitude and duration of primary and secondary peristalsis. Acute esophageal acid infusion can induce greater mechanosensitivity to distension-induced secondary peristalsis than 5-HT₄ receptors agonist mosapride. The data suggest that acid-sensitive afferents are more likely to contribute to sensory modulation of esophageal secondary peristalsis; however, the motility aspects of secondary peristalsis are comparable between acute esophageal acidification and 5-HT₄ receptors activation via mosapride.

Chili Peppers, Curcumins, and Prebiotics in Gastrointestinal Health and Disease

There is growing evidence for the role of several natural products as either useful agents or adjuncts in the management of functional GI disorders (FGIDs). In this review, we examine the medical evidence for three such compounds: chili, a culinary spice; curcumin, another spice and active derivative of a root bark; and prebiotics, which are nondigestible food products. Chili may affect the pathogenesis of abdominal pain especially in functional dyspepsia and cause other symptoms. It may have a therapeutic role in FGIDs through desensitization of transient receptor potential vanilloid-1 receptor. Curcumin, the active ingredient of turmeric rhizome, has been shown in several preclinical studies and uncontrolled clinical trials as having effects on gut inflammation, gut permeability and the brain-gut axis, especially in FGIDs. Prebiotics, the non-digestible food ingredients in dietary fiber, may serve as nutrients and selectively stimulate the growth and/or activity of certain colonic bacteria. The net effect of this change on colonic microbiota may lead to the production of acidic metabolites and other compounds that help to reduce the production of toxins and suppress the growth of harmful or disease-causing enteric pathogens. Although some clinical benefit in IBS has been shown, high dose intake of prebiotics may cause more bloating from bacterial fermentation.

Influence of capsaicin infusion on secondary peristalsis in patients with gastroesophageal reflux disease

AIM

To determine whether capsaicin infusion could influence heartburn perception and secondary peristalsis in patients with gastroesophageal reflux disease (GERD).

METHODS

Secondary peristalsis was performed with slow and rapid mid-esophageal injections of air in 10 patients with GERD. In a first protocol, saline and capsaicin-containing red pepper sauce infusions were randomly performed, whereas 2 consecutive sessions of capsaicin-containing red pepper sauce infusions were performed in a second protocol. Tested solutions including 5 mL of red pepper sauce diluted with 15 mL of saline and 20 mL of 0.9% saline were infused into the mid-esophagus via the manometric catheter at a rate of 10 mL/min with a randomized and double-blind fashion. During each study protocol, perception of heartburn, threshold volumes and peristaltic parameters for secondary peristalsis were analyzed and compared between different stimuli.

RESULTS

Infusion of capsaicin significantly increased heartburn perception in patients with GERD (P < 0.001), whereas repeated capsaicin infusion significantly reduced heartburn perception (P = 0.003). Acute capsaicin infusion decreased threshold volume of secondary peristalsis (P = 0.001) and increased its frequency (P = 0.01) during rapid air injection. The prevalence of GERD patients with successive secondary peristalsis during slow air injection significantly increased after capsaicin infusion (P = 0.001). Repeated capsaicin infusion increased threshold volume of secondary peristalsis (P = 0.002) and reduced the frequency of secondary peristalsis (P = 0.02) during rapid air injection.

CONCLUSION

Acute esophageal exposure to capsaicin enhances heartburn sensation and promotes secondary peristalsis in gastroesophageal reflux disease, but repetitive capsaicin infusion reverses these effects.

Sleep disturbance and enhanced esophageal capsaicin sensitivity in patients with gastroesophageal reflux disease

BACKGROUND AND AIM

Esophageal infusion of capsaicin-containing red pepper sauce induced heartburn symptoms in patients with gastroesophageal reflux disease (GERD). We aimed to test the hypothesis whether sleep disturbance modulates esophageal sensitivity to capsaicin infusion in patients with GERD.

METHODS

We enrolled 40 patients with their sleep quality measured by the Pittsburg Sleep Quality Index with > 5 indicating sleep disturbance. Esophageal sensation to capsaicin infusion was documented via measures of lag time to initial heartburn perception, heartburn intensity rating, and sensitivity score by esophageal infusion of capsaicin-containing red pepper sauce. Objective sleep measures were assessed by ambulatory actigraphy.

RESULTS

We found 22 patients with sleep disturbance. The patients with sleep disturbance had shorter lag time to initial heartburn perception (P = 0.03) and greater sensory intensity rating (P = 0.02). The sensitivity score for capsaicin infusion was greater in patients with sleep disturbance when compared with those without sleep disturbance (P = 0.04). Actigraphy measures revealed that patients with sleep disturbance also had poor sleep efficiency (P = 0.04), longer average awakening time (P = 0.03), and greater total activity account (P = 0.04). The lag time for perceiving capsaicin infusion was positively correlated with total sleep time (r = 0.43, P = 0.03).

CONCLUSIONS

We have shown that GERD patients with sleep disturbance have significantly enhanced heartburn perception to capsaicin infusion as compared with those with normal sleep. Our findings suggest that sleep disturbance is associated with esophageal hypersensitivity to capsaicin infusion in patients with GERD.

Effects of esophageal capsaicin instillation on acid induced excitation of secondary peristalsis in humans

BACKGROUND/AIM

Esophageal instillation of capsaicin or hydrochloric acid enhances secondary peristalsis. Our aim was to investigate whether intra-esophageal capsaicin infusion can influence symptom perception and physiological alteration of secondary peristalsis subsequent to acid infusion.

METHODS

Secondary peristalsis was induced by mid-esophagus injections of air in 18 healthy subjects. Two different sessions including esophageal infusion of hydrochloric acid (0.1 N) following pretreatment with saline or capsaicin-containing red pepper sauce were randomly performed at least one week apart. Symptoms of heartburn and secondary peristalsis were determined and compared between each study session.

RESULTS

The intensity of heartburn symptom subsequent to acid infusion was significantly reduced after capsaicin infusion as compared with saline infusion (54 ± 3 vs 61 ± 3; P = 0.03). Capsaicin infusion significantly increased the threshold volume of secondary peristalsis to rapid air injections subsequent to esophageal acid infusion (8.0 ± 0.5 mL vs 4.4 ± 0.3 mL; P < 0.0001). The frequency of secondary peristalsis subsequent to acid infusion was significantly decreased after capsaicin infusion as compared to saline infusion (70% [60-82.5%] vs 80% [70-90%]; P = 0.03). Capsaicin infusion significantly decreased the pressure wave amplitude of secondary peristalsis subsequent to acid infusion during rapid air injections (90.6 ± 8.7 mmHg vs 111.1 ± 11.1 mmHg; P = 0.03).

CONCLUSIONS

Capsaicin appears to desensitize the esophagus to acid induced excitation of secondary peristalsis in humans, which is probably mediated by rapidly adapting mucosal mechanoreceptors. High capsaicin-containing diet might attenuate normal physiological response to abrupt acid reflux by inhibiting secondary peristalsis.

Influence of repeated infusion of capsaicin-contained red pepper sauce on esophageal secondary peristalsis in humans

BACKGROUND

The transient receptor potential vanilloid 1 has been implicated as a target mediator for heartburn perception and modulation of esophageal secondary peristalsis. Our aim was to determine the effect of repeated esophageal infusion of capsaicin-contained red pepper sauce on heartburn perception and secondary peristalsis in healthy adults.

METHODS

Secondary peristalsis was performed with mid-esophageal injections of air in 15 healthy adults. Two separate protocols including esophageal infusion with saline and capsaicin-contained red pepper sauce and 2 consecutive sessions of capsaicin-contained red pepper sauce were randomly performed.

KEY RESULTS

After repeated infusion of capsaicin-contained red pepper sauce, the threshold volume to activate secondary peristalsis was significantly increased during slow (p < 0.001) and rapid air injections (p = 0.004). Acute infusion of capsaicin-contained red pepper sauce enhanced heartburn perception (p < 0.001), but the intensity of heartburn perception was significantly reduced after repeated capsaicin-contained red pepper sauce infusion (p = 0.007). Acute infusion of capsaicin-contained red pepper sauce significantly increased pressure wave amplitudes of distal esophagus during slow (p = 0.003) and rapid air injections (p = 0.01), but repeated infusion of capsaicin-contained red pepper sauce significantly decreased pressure wave amplitude of distal esophagus during slow (p = 0.0005) and rapid air injections (p = 0.003).

CONCLUSIONS & INFERENCES

Repeated esophageal infusion of capsaicin appears to attenuate heartburn perception and inhibit distension-induced secondary peristalsis in healthy adults. These results suggest capsaicin-sensitive afferents in modulating sensorimotor function of secondary peristalsis in human esophagus.