Integrative Effects and Vagal Mechanisms of Transcutaneous Electrical Acustimulation on Gastroesophageal Motility in Patients With Gastroesophageal Reflux Disease

Unveiling the intricacies: Insight into gastroesophageal reflux disease

Gastroesophageal reflux disease (GERD) poses a substantial global health challenge, with prevalence rates exhibiting geographical variation. Despite its widespread recognition, the exact prevalence and associated risk factors remain elusive. This article comprehensively analyzed the global burden of GERD, shedding light on its risk factors, underlying pathophysiological mechanisms, current diagnostic modalities, evolving management strategies tailored to diverse patient profiles, and complex determinants contributing to treatment failures. A deeper comprehension of GERD is achieved by dissecting these intricate facets, paving the way for enhanced clinical management and improved patient outcomes.

Integrative Effects of Transcutaneous Electrical Acustimulation and Autonomic-Endocrine Mechanisms on Postprocedural Recovery in Patients With Endoscopic Retrograde Cholangio-Pancreatography

OBJECTIVES

This study aimed to investigate the integrative effects and mechanisms of transcutaneous electrical acustimulation (TEA) on postprocedural recovery from endoscopic retrograde cholangio-pancreatography (ERCP).

MATERIALS AND METHODS

A total of 86 patients for elective ERCP were randomly ordered to receive TEA (n = 43) at acupoints PC6 and ST36 or Sham-TEA (n = 43) at sham points from 24 hours before ERCP (pre-ERCP) to 24 hours after ERCP (PE24). Scores of gastrointestinal (GI) motility-related symptoms and abdominal pain, gastric slow waves, and autonomic functions were recorded through the spectral analysis of heart rate variability; meanwhile, circulatory levels of inflammation cytokines of tumor necrosis factor-α (TNF-α) and interleukin (IL)-10 and GI hormones of motilin, ghrelin, cholecystokinin (CCK), and vasoactive intestinal peptide (VIP) were assessed by enzyme-linked immunosorbent assay.

RESULTS

1) TEA, but not Sham-TEA, decreased the post-ERCP GI motility-related symptom score (2.4 ± 2.6 vs 7.9 ± 4.6, p < 0.001) and abdominal pain score (0.5 ± 0.7 vs 4.1 ± 2.7, p < 0.001) at PE24, and decreased the post-ERCP hospital day by 20.0% (p ＜0.05 vs Sham-TEA); 2) TEA improved the average gastric percentage of normal slow waves and dominant frequency by 34.6% and 33.3% at PE24, respectively (both p < 0.001 vs Sham-TEA); 3) TEA, but not Sham-TEA, reversed the ERCP-induced increase of TNF-α but not IL-10 at PE24, reflected as a significantly lower level of TNF-α in the TEA group than in the Sham-TEA group (1.6 ± 0.5 pg/mL vs 2.1 ± 0.9 pg/mL, p ＜ 0.01); 4) compared with Sham-TEA, TEA increased vagal activity by 37.5% (p ＜ 0.001); and 5) TEA caused a significantly higher plasma level of ghrelin (1.5 ± 0.8 ng/ml vs 1.1 ± 0.7 ng/ml, p ＜ 0.05) but not motilin, VIP, or CCK than did Sham-TEA at PE24.

CONCLUSION

TEA at PC6 and ST36 accelerates the post-ERCP recovery, reflected as the improvement in GI motility and amelioration of abdominal pain, and suppression of the inflammatory cytokine TNF-α may mediate through both autonomic and ghrelin-related mechanisms.

Vagus nerve stimulation (VNS): recent advances and future directions

PURPOSE

Vagus nerve stimulation (VNS) is emerging as a unique and potent intervention, particularly within neurology and psychiatry. The clinical value of VNS continues to grow, while the development of noninvasive options promises to change a landscape that is already quickly evolving. In this review, we highlight recent progress in the field and offer readers a glimpse of the future for this bright and promising modality.

METHODS

We compiled a narrative review of VNS literature using PubMed and organized the discussion by disease states with approved indications (epilepsy, depression, obesity, post-stroke motor rehabilitation, headache), followed by a section highlighting novel, exploratory areas of VNS research. In each section, we summarized the current role, recent advancements, and future directions of VNS in the treatment of each disease.

RESULTS

The field continues to gain appreciation for the clinical potential of this modality. VNS was initially developed for treatment-resistant epilepsy, with the first depression studies following shortly thereafter. Overall, VNS has gained approval or clearance in the treatment of medication-refractory epilepsy, treatment-resistant depression, obesity, migraine/cluster headache, and post-stroke motor rehabilitation.

CONCLUSION

Noninvasive VNS represents an opportunity to bridge the translational gap between preclinical and clinical paradigms and may offer the same therapeutic potential as invasive VNS. Further investigation into how VNS parameters modulate behavior and biology, as well as how to translate noninvasive options into the clinical arena, are crucial next steps for researchers and clinicians studying VNS.

The mechanism of transcutaneous gastric pacing treatment on gastrointestinal motility recovery and inflammation improvement in early-stage acute pancreatitis patients

PURPOSE

Acute pancreatitis (AP) is often accompanied by gastrointestinal motility disorders. The purpose of this study was to investigate the efficacy and possible mechanism of transcutaneous gastric pacing (TGP) in early-stage AP patients.

MATERIALS AND METHODS

Sixty-five AP patients were randomly divided into conventional treatment group and TGP group. The serum ghrelin and vasoactive intestinal peptide (VIP) were used to assess the possible gastrointestinal hormonal mechanism involved. The parameters of electrogastrogram (EGG) were used to evaluate the gastric motility in AP patients. The first defecation time was used to assess the recovery of intestinal motility. The heart rate variability (HRV) test was performed to assess autonomic nervous function.

RESULTS

Compared with the conventional treatment group, the TGP treatment significantly improved symptoms in early AP patients, and shortened the first defecation time (p < 0.05) and the hospital days (p < 0.05). The level of VIP (P < 0.05) was also decreased in TGP group. The percentage of normal gastric slow waves (GSWS) (p < 0.05) was increased. The interleukin (IL)-6 level was decreased (P < 0.05). Concurrently, the vagal activity (HF) was increased (p < 0.01), the sympathetic activity (LF) was decreased (p < 0.01), and the ratio of sympathetic vagal (LF/HF) was decreased (p < 0.01).

CONCLUSIONS

The TGP treatment significantly improves the clinical symptoms in early AP patients. It also increases the percentage of normal GSWS. The therapeutic effect of TGP may be caused by autonomic nervous function mechanisms.

The impact of transcutaneous electrical acustimulation (TEA) on rectal distension-induced pain in patients with irritable bowel syndrome (IBS)-A study to determine the optimal TEA delivery modalities and effects on rectal sensation and autonomic function

BACKGROUND

Treatment options for abdominal pain in IBS are inadequate. TEA was reported effective treatment of disorders of gut-brain interaction but its mechanism of action and optimal delivery method for treating pain in IBS are unknown. This study aims to determine the most effective TEA parameter and location to treat abdominal pain in patients with IBS-Constipation and delineate the effect of TEA on rectal sensation and autonomic function.

METHODS

Nineteen IBS-C patients underwent TEA at acupoints ST36 (leg), PC6 (wrist), or sham-acupoint. Each patient was studied in five randomized sessions on separate days: (1) TEA/ST36-100 Hz; (2) TEA/ST36-25 Hz; (3) TEA/PC6-100 Hz; (4) TEA/PC6-25 Hz; (5) TEA/Sham-25 Hz. In each session, barostat-guided rectal distention (RD) was performed before and after TEA. Patients graded the RD-induced pain and recorded three rectal sensation thresholds. A heart rate variability (HRV) signal was derived from the electrocardiogram for autonomic function assessment.

KEY RESULTS

Studied patients were predominantly female, young, and Caucasian. Compared with baseline, patients treated with TEA/ST36-100 Hz had significantly decreased pain scores at RD pressure-points 20-50 mmHg (p < 0.04). The average pain reduction was 40%. Post-treatment scores did not change significantly with other TEA modalities except with sham-TEA (lesser degree compared to ST36-100 Hz, p = 0.04). TEA/ST36-100, but not other modalities, increased the rectal sensation threshold (first sensation: p = 0.007; urge to defecate: p < 0.026). TEA/ST36-100 Hz was the only treatment that significantly decreased sympathetic activity and increased parasympathetic activity with and without RD (p < 0.04).

CONCLUSIONS & INFERENCES

TEA at ST36-100 Hz is superior stimulation point/parameter, compared to TEA at PC-6/sham-TEA, to reduce rectal distension-induced pain in IBS-C patients. This therapeutic effect appears to be mediated through rectal hypersensitivity reduction and autonomic function modulation.

Electroceuticals and Magnetoceuticals in Gastroenterology

In the realm of gastroenterology, the inadequacy of current medical treatments for gastrointestinal (GI) motility disorders and inflammatory bowel disease (IBD), coupled with their potential side effects, necessitates novel therapeutic approaches. Neuromodulation, targeting the nervous system's control of GI functions, emerges as a promising alternative. This review explores the promising effects of vagal nerve stimulation (VNS), magnetic neuromodulation, and acupuncture in managing these challenging conditions. VNS offers targeted modulation of GI motility and inflammation, presenting a potential solution for patients not fully relieved from traditional medications. Magnetic neuromodulation, through non-invasive means, aims to enhance neurophysiological processes, showing promise in improving GI function and reducing inflammation. Acupuncture and electroacupuncture, grounded in traditional medicine yet validated by modern science, exert comprehensive effects on GI physiology via neuro-immune-endocrine mechanisms, offering relief from motility and inflammatory symptoms. This review highlights the need for further research to refine these interventions, emphasizing their prospective role in advancing patient-specific management strategies for GI motility disorders and IBD, thus paving the way for a new therapeutic paradigm.

Neuromodulation and the Gut-Brain Axis: Therapeutic Mechanisms and Implications for Gastrointestinal and Neurological Disorders

The gut-brain axis (GBA) represents a complex, bidirectional communication network that intricately connects the gastrointestinal tract with the central nervous system (CNS). Understanding and intervening in this axis opens a pathway for therapeutic advancements for neurological and gastrointestinal diseases where the GBA has been proposed to play a role in the pathophysiology. In light of this, the current review assesses the effectiveness of neuromodulation techniques in treating neurological and gastrointestinal disorders by modulating the GBA, involving key elements such as gut microbiota, neurotrophic factors, and proinflammatory cytokines. Through a comprehensive literature review encompassing PubMed, Google Scholar, Web of Science, and the Cochrane Library, this research highlights the role played by the GBA in neurological and gastrointestinal diseases, in addition to the impact of neuromodulation on the management of these conditions which include both gastrointestinal (irritable bowel syndrome (IBS), inflammatory bowel disease (IBD), and gastroesophageal reflux disease (GERD)) and neurological disorders (Parkinson's disease (PD), Alzheimer's disease (AD), autism spectrum disorder (ASD), and neuropsychiatric disorders). Despite existing challenges, the ability of neuromodulation to adjust disrupted neural pathways, alleviate pain, and mitigate inflammation is significant in improving the quality of life for patients, thereby offering exciting prospects for future advancements in patient care.

The Overlap Subgroup of Functional Dyspepsia Exhibits More Severely Impaired Gastric and Autonomic Functions

GOALS

A combination of multiple tests was introduced to noninvasively investigate the differences in pathophysiologies among functional dyspepsia (FD) subgroups, including postprandial distress syndrome (PDS), epigastric pain syndrome (EPS), and overlap.

BACKGROUND

It has not been extensively evaluated whether different pathophysiologies are involved in FD subgroups.

STUDY

This multicenter study included 364 FD patients fulfilling Rome IV criteria and 47 healthy controls. A combined noninvasive gastric and autonomic function test was performed: The electrogastrogram and electrocardiogram were recorded simultaneously in the fasting state and after a drink test. Symptoms after drinking were recorded using visual analog scale.

RESULTS

(1) Compared with HC, FD patients showed a decreased maximum tolerable volume (MTV) ( P <0.01) and percentage of normal gastric slow waves [normal gastric slow waves (%NSW)] ( P <0.01), and increased postdrinking symptoms, anxiety ( P <0.01), and depression ( P <0.01). The drink reduced %NSW in both FD patients and HC; however, the effect was more potent in patients. (2) The PDS and overlap groups displayed a reduced MTV ( P <0.05). The overlap group exhibited a higher symptom score at 30 minutes after drinking, and higher anxiety and depression scores, and a higher sympathovagal ratio than the EPS ( P <0.05 for all) and PDS ( P <0.01 for all). (3) In the PDS subgroup, the MTV, postprandial sympathovagal ratio, and depression were associated with the overall dyspepsia symptom scale (DSS, P =0.034, 0.021, 0.043, respectively). No significant associations were found in the other 2 subgroups.

CONCLUSIONS

The combination of multiple tests can detect pathophysiological abnormities in FD patients. Overall, patients with overlap symptoms display more severe pathophysiologies.

Noninvasive Transcutaneous Auricular Vagal Nerve Stimulation Improves Gastric Slow Waves Impaired by Cold Stress in Healthy Subjects

BACKGROUND/AIMS

Stress is known to inhibit gastric motility. The aim of this study was to investigate the effects and autonomic mechanisms of transcutaneous auricular vagal nerve stimulation (taVNS) on cold stress (CS)-induced impairment in gastric motility that are relevant to the brain-gut interactions in healthy volunteers.

MATERIALS AND METHODS

Healthy volunteers (eight women; age 28.2 ± 1.8 years) were studied in four randomized sessions (control, CS, CS + taVNS, and CS + sham-electrical stimulation [sham-ES]). Each session was composed of 30 minutes in the fasting state and 30 minutes after a standard test meal. CS was induced during minutes 10 to 30 after the meal, whereas taVNS or sham-ES was performed during minutes 0 to 30 after the meal. The electrogastrogram and electrocardiogram were recorded for assessing gastric slow waves and autonomic functions, respectively.

RESULTS

First, CS decreased the percentage of normal gastric slow waves (59.7% ± 9.8% vs 85.4% ± 4.5%, p < 0.001 vs control); this impairment was dramatically improved by taVNS (75.5% ± 6.3% vs 58.4% ± 12.5%, p < 0.001 vs sham-ES). Second, CS increased the symptom score (22.0 ± 12.1 vs 39.3 ± 11.5, p = 0.001 vs control); taVNS, but not sham-ES, reduced the symptom score (26.0 ± 12.2 vs 38.3 ± 21.6, p = 0.026 vs sham-ES). Third, CS decreased vagal activity assessed from the spectral analysis of heart rate variability (0.21 ± 0.10 vs 0.26 ± 0.11, p < 0.05 vs control) and increased the sympathovagal ratio (4.89 ± 1.94 vs 3.74 ± 1.32, p = 0.048 vs control); taVNS normalized CS-induced suppression in vagal activity (0.27 ± 0.13 vs 0.22 ± 0.10, p = 0.049 vs sham-ES; p > 0.05 vs control) and CS-induced increase in the sympathovagal ratio (3.28 ± 1.61 vs 4.28 ± 2.10, p = 0.042 vs sham-ES; p > 0.05 vs control).

CONCLUSION

The noninvasive taVNS improves the CS-induced impairment in gastric pace-making activity, possibly by reversing the detrimental effect of CS on autonomic functions. taVNS may have a therapeutic potential for stress-induced gastric dysmotility.

Noninvasive electrical neuromodulation for gastrointestinal motility disorders

INTRODUCTION

Gastrointestinal motility disorders are highly prevalent without satisfactory treatment. noninvasive electrical neuromodulation is an emerging therapy for treating various gastrointestinal motility disorders.

AREAS COVERED

In this review, several emerging noninvasive neuromodulation methods are introduced, including transcutaneous auricular vagal nerve stimulation, percutaneous auricular vagal nerve stimulation, transcutaneous cervical vagal nerve stimulation, transcutaneous electrical acustimulation, transabdominal interference stimulation, tibial nerve stimulation, and translumbosacral neuromodulation therapy. Their clinical applications in the most common gastrointestinal motility are discussed, including gastroesophageal reflux disease, functional dyspepsia, gastroparesis, functional constipation, irritable bowel syndrome, and fecal incontinence. PubMed database was searched from 1995 to June 2023 for relevant articles in English.

EXPERT OPINION

Noninvasive neuromodulation is effective and safe in improving both gastrointestinal symptoms and dysmotility; it can be used when pharmacotherapy is ineffective. Future directions include refining the methodology, improving device development and understanding mechanisms of action.

Non-invasive neuromodulation: an emerging intervention for visceral pain in gastrointestinal disorders

Gastrointestinal (GI) disorders, which extend from the esophagus to the anus, are the most common diseases of the GI tract. Among these disorders, pain, encompassing both abdominal and visceral pain, is a predominant feature, affecting the patients' quality of life and imposing a substantial financial burden on society. Pain signals originating from the gut intricately shape brain dynamics. In response, the brain sends appropriate descending signals to respond to pain through neuronal inhibition. However, due to the heterogeneous nature of the disease and its limited pathophysiological understanding, treatment options are minimal and often controversial. Consequently, many patients with GI disorders use complementary and alternative therapies such as neuromodulation to treat visceral pain. Neuromodulation intervenes in the central, peripheral, or autonomic nervous system by alternating or modulating nerve activity using electrical, electromagnetic, chemical, or optogenetic methodologies. Here, we review a few emerging noninvasive neuromodulation approaches with promising potential for alleviating pain associated with functional dyspepsia, gastroparesis, irritable bowel syndrome, inflammatory bowel disease, and non-cardiac chest pain. Moreover, we address critical aspects, including the efficacy, safety, and feasibility of these noninvasive neuromodulation methods, elucidate their mechanisms of action, and outline future research directions. In conclusion, the emerging field of noninvasive neuromodulation appears as a viable alternative therapeutic avenue for effectively managing visceral pain in GI disorders.

Current complementary and alternative therapy forgastroesophageal reflux disease

Gastroesophageal reflux disease (GERD) is a widely prevalent gastrointestinal disorder, affecting ∼13.3% of the global population. There are shortages and limitations of current GERD treatment modalities, and complementary and alternative therapy (CAT) is a promising option to fill in the gap. Dietary and lifestyle modifications might play an important and complementary role in alleviating GERD symptoms. Traditional Chinese medicine and brain-gut behavior therapy, particularly transcutaneous electrical acustimulation and diaphragmatic breathing therapy were shown to be useful adjuncts or alternatives in treating GERD. CAT may help to relieve GERD symptoms, minimize medication dosage, and slow the demand for surgery. The aim of this review was to summarize the existing evidence of some common CATs in treating symptomatic GERD, including dietary modification, lifestyle change, traditional Chinese medicine, and brain-gut behavior therapy.

Acceleration of postoperative recovery with brief intraoperative vagal nerve stimulation mediated via the autonomic mechanism

Introduction

Postoperative recovery is largely dependent on the restoration of gastrointestinal motility. The aim of this study was to investigate the effects and mechanisms of intraoperative vagus nerve stimulation (iVNS) on postoperative recovery from abdominal surgery in rats.

Methods

The Nissen fundoplication surgery was performed on two groups of rats: sham-iVNS group and iVNS group (VNS was performed during surgery). Animal's behavior, eating, drinking and feces' conditions were monitored at specific postoperative days. Gastric slow waves (GSWs) and electrocardiogram (ECG) were recorded; blood samples were collected for the assessment of inflammatory cytokines.

Results

(1) iVNS shortened initiate times to water and food intake (p = 0.004) and increased the number of fecal pellets (p < 0.05, vs. sham-iVNS) and the percentage of water content in fecal pellets (p < 0.05). (2) iVNS improved gastric pace-making activity at 6 h after surgery reflected as a higher percentage of normal slow waves (p = 0.015, vs. sham-iVNS). (3) iVNS suppressed inflammatory cytokines at 24 h after surgery compared to sham-iVNS (TNF-α: p = 0.001; IL-1β: p = 0.037; IL-6: p = 0.002). (4) iVNS increased vagal tone compared to sham-iVNS group at 6 h and 24 h after the surgery (p < 0.05). Increased vagal tone was correlated with a faster postoperative recovery to start water and food intake.

Conclusion

Brief iVNS accelerates postoperative recovery by ameliorating postoperative animal behaviors, improving gastrointestinal motility and inhibiting inflammatory cytokines mediated via the enhanced vagal tone.

Systemic sclerosis gastrointestinal dysmotility: risk factors, pathophysiology, diagnosis and management

Nearly all patients with systemic sclerosis (SSc) are negatively affected by dysfunction in the gastrointestinal tract, and the severity of gastrointestinal disease in SSc correlates with high mortality. The clinical complications of this dysfunction are heterogeneous and include gastro-oesophageal reflux disease, gastroparesis, small intestinal bacterial overgrowth, intestinal pseudo-obstruction, malabsorption and the requirement for total parenteral nutrition. The abnormal gastrointestinal physiology that promotes the clinical manifestations of SSc gastrointestinal disease throughout the gastrointestinal tract are diverse and present a range of therapeutic targets. Furthermore, the armamentarium of medications and non-pharmacological interventions that can benefit affected patients has substantially expanded in the past 10 years, and research is increasingly focused in this area. Here, we review the details of the gastrointestinal complications in SSc, tie physiological abnormalities to clinical manifestations, detail the roles of standard and novel therapies and lay a foundation for future investigative work.

Clinical efficacy and mechanism of transcutaneous neuromodulation on ineffective esophageal motility in patients with gastroesophageal reflux disease

BACKGROUND

Esophageal motility disorder is one of the pathogenesis of gastroesophageal reflux disease (GERD). The clinical and functional relationship between the ineffective esophageal motility (IEM) and GERD have been found. PPI is a widely used drug of this diaease, but some patients have poor efficacy. The purpose of this study was to investigate the efficacy and possible mechanism of Transcutaneous Neuromodulation in these patients.

METHODS

Fifty-six patients with GERD with IEM were enrolled and randomly divided into two groups, one group was TN ST-36 group, the other group was sham TN group. The GERD questionnaire (GerdQ), quality of life score, MOS item short from health survey (SF-36), Hospital Anxiety and Depression Scale (HADS) were used to assess the severity of symptoms. High-resolution esophageal manometry (HRM) test was performed to assess low esophageal sphincter (LES) pressure and distal contractile integral (DCI). The heart rate variability (HRV) test was performed to assess autonomic nervous function.

KEY RESULTS

Compared with sham TN, chronic TN treatment decreased the GERD-Q score (p < 0.001). The anxiety score (p = 0.058) and depression score (p = 0.156) were decreased, but there were no statistical differences. Chronic TN treatment also significantly improved the quality of life of patients, mainly in physical function, physical pain, overall health, vitality, social function, emotional function, and mental health. Acute TN treatment increased the DCI (p < 0.001) and LES pressure (p < 0.001) significantly and decreased the combined percentage of failed and weak peristalsis (p < 0.001). Concurrently, acute TN enhanced vagal activity (p < 0.001).

CONCLUSIONS AND INFERENCES

IEM is an important link in the pathogenesis of GERD. Chronic TN treatment can significantly improve the clinical symptoms of patients. Acute TN treatment can significantly increase LES pressure and DCI and reduce the frequency of esophageal lost peristalsis and weak peristalsis. The improvement of esophageal motility in GERD patients with IEM by TN treatment may be related to the regulation of autonomic nervous function.

A bibliometric analysis of 100 top-cited journal articles related to acupuncture regulation of the autonomic nervous system

Purpose

Research on the effects of acupuncture on autonomic function has been conducted for several decades, and a few notable studies have emerged in recent years. This study used bibliometric analysis to assess 100 top-cited articles to characterize the current status and research trends over the last three decades.

Methods

The 100 top-cited publications were identified from the Web of Science Core Collection database. The bibliometrix package in R was used for quantitative and qualitative analyses of the publication patterns and the country/region, institution, and author contributions. VOSviewer was used to construct networks based on co-citation analysis of the journals and the keyword co-occurrence.

Results

The 100 top-cited articles were identified with a total of 8,123 citations (range: 37-345). The majority of the articles came from the USA (n = 42), followed by Japan (n = 14) and mainland China (n = 13). Articles from the USA exhibited the largest number of citations (3,582 citations), followed by articles from Japan (1,189 citations), then articles from mainland China (755 citations). Neurosciences/Neurology was the most studied research area (n = 41). The Autonomic Neuroscience: Basic and Clinical published the largest number of papers (n = 14), while Brain Research received the largest number of citations (205 citations). Longhurst JC was the most productive author (10 publications), and Sato A was first among the cited authors (87 citations). The most frequently cited articles that focused on gastrointestinal, cardiovascular, or gynecologic responses to acupuncture regulation of the autonomic nervous system first appeared in the 1990s, peaked in the 2000s, then decreased after 2010. Publication of articles focused on the anti-inflammatory effects of acupuncture associated with autonomic function demonstrated an increasing trend over the last three decades.

Conclusion

From the initial studies focusing on the autonomic mechanism of visceral responses to acupuncture, researchers concentrated on exploring the autonomic mechanism of acupuncture in the control of systemic inflammation. Non-invasive electrical methods that activate somato-autonomic reflexes are current translational directions in clinical practice. Additional investigation of the underlying neuroanatomical basis of somato-autonomic reflexes also is needed.

Sustained ameliorating effects and autonomic mechanisms of transcutaneous electrical acustimulation at ST36 in patients with chronic constipation

BACKGROUND AND AIMS

The treatment of chronic constipation is still a great challenge in clinical practice. This study aimed to determine the efficacy and sustained effects of transcutaneous electrical acustimulation (TEA) at acupoint ST36 on the treatment of chronic constipation and explore possible underlying mechanisms.

METHODS

Forty-four patients with chronic constipation were recruited and randomly assigned to a TEA group or sham-TEA group. A bowel diary was recorded by the patients. The Patient Assessment of Constipation Symptom (PAC-SYM) and the Patient Assessment of Constipation Quality of Life (PAC-QoL) questionnaires were administered during each visit. Anal and rectal functions were evaluated with anorectal manometry. Autonomic functions were assessed by the special analysis of heart rate variability derived from the ECG recording.

RESULTS

Compared with sham-TEA, 2-week TEA treatment significantly increased the number of spontaneous bowel movements (SBMs) (5.64 ± 0.54 vs. 2.82 ± 0.36, P < 0.001) and lowered the total scores of PAC-SYM (0.90 ± 0.14 vs. 1.35 ± 0.13, P < 0.001) and PAC-QoL (0.89 ± 0.13 vs. 1.32 ± 0.14, P < 0.05). TEA improved symptoms, as reflected by a reduction in the straining (P < 0.001), the incomplete defecation (P < 0.05), the frequency of emergency drug use (P < 0.05), the days of abdominal distension (P < 0.01) and an increase in intestinal satisfaction (P < 0.01). Interestingly, the effects of TEA on the improvement of weekly SBMs sustained four weeks after the cessation of treatment (P < 0.001). Anorectal manometry indicated that 2-week treatment of TEA lowered the threshold of first sensation (P < 0.05), desire of defecation (P < 0.01) and maximum tolerable volume (P < 0.001) compared with sham-TEA group. TEA also significantly enhanced vagal activity, reflected by high-frequency band of heart rate variability, compared with sham-TEA (57.86 ± 1.83 vs. 48.51 ± 2.04, P < 0.01).

CONCLUSION

TEA ameliorates constipation with sustained effects, which may be mediated via improvement of rectal sensitivity and enhancement of vagal activity.

CLINICAL TRIAL REGISTRATION

[https://clinicaltrials.gov/], identifier [ChiCTR210004267].

Updates in interaction of gastroesophageal reflux disease and extragastroesophageal digestive diseases

INTRODUCTION

Gastroesophageal reflux disease (GERD) is one of the common chronic diseases with prevalence increasing in the last decades. Because of its prevalence and chronicity, GERD affects the quality of life and increases health-care costs. Gastroesophageal diseases leading to GERD have been thoroughly studied, while extragastroesophageal digestive diseases (EGEDDs) may coexist with GERD and affect the occurrence and persistence of GERD symptoms and therapeutic effect.

AREAS COVERED

In this review, we aim to summarize the EGEDDs correlated with GERD and explore the potential mechanisms of this interaction.

EXPERT OPINION

Individuals with troublesome GERD symptoms may have some common gastroesophageal etiologies, but EGEDDs may also overlap and impact on the progression of GERD, which are often ignored in clinic. The lesions in the small intestine, colon, and hepatobiliary tract as well as functional bowel disorders had positive or negative associations with GERD through potential mechanisms. These diseases aggravate GERD symptoms, increase the esophageal acid burden, cause esophageal hypersensitivity, and finally affect the response to therapy in GERD patients. Therefore, it is necessary to clear the interaction between GERD and EGEDDs and their mechanisms.

Transcutaneous Electrical Acustimulation Improves Irritable Bowel Syndrome With Constipation by Accelerating Colon Transit and Reducing Rectal Sensation Using Autonomic Mechanisms

INTRODUCTION

Slow colon transit and visceral hypersensitivity are recognized as major pathophysiological mechanisms in irritable bowel syndrome with constipation (IBS-C). However, there is a lack of therapies targeting both abdominal pain and colonic motility. This study was designed to investigate the long-term effects and possible mechanisms of transcutaneous electrical acustimulation (TEA) in patients with IBS-C.

METHODS

Fifty-two patients with IBS-C were randomized into 2 groups: daily TEA for 4 weeks (n = 26) and daily sham-TEA for 4 weeks (n = 26). The number of complete spontaneous bowel movements per week (CSBMs/week, primary outcome), Irritable Bowel Syndrome Severity Scoring System, Patient Assessment of Constipation Quality of Life, visual analog scale (VAS) pain score, colonic transit time, and anorectal physiology were evaluated before treatment and at the end of the treatment. Colonic transit was assessed with radiopaque markers. Electrocardiograms were recorded for assessing autonomic functions.

RESULTS

(i) TEA improved constipation and abdominal pain. After the treatment, the number of CSBMs/week during the last week in the TEA group was higher than that in the sham-TEA group (3.5 ± 1.6 vs 2.3 ± 0.6, P = 0.002). Similar effects were also noted in the visual analog scale pain score ( P = 0.002) and Irritable Bowel Syndrome Severity Scoring System score ( P = 0.025). In addition, there was a significant improvement in the quality of life of patients with constipation. The Patient Assessment of Constipation Quality of Life total score was significantly decreased in the TEA group ( P = 0.004). (ii) Compared with sham-TEA, TEA improved colon transit ( P = 0.002) and increased the threshold of rectal sensation (desire to defecate, P = 0.004; maximum tolerability, P &lt; 0.001). (iii) TEA increased vagal activity, compared with sham-TEA ( P &lt; 0.05); at the end of the treatment, the vagal activity was significantly correlated with colon transit and the CSBMs/week.

DISCUSSION

TEA improves constipation and symptoms of IBS by accelerating colon transit and reducing rectal sensation, possibly mediated by using the autonomic mechanisms.