Transcutaneous Neuromodulation at ST36 (Zusanli) is More Effective than Transcutaneous Tibial Nerve Stimulation in Treating Constipation

Accelerative Effects of Transcutaneous Electrical Acustimulation on Postoperative Recovery After Thoracolumbar Vertebral Fracture Associated With Suppressed Sympathetic Activity and Interleukin-6

OBJECTIVES

Gastrointestinal (GI) disturbance is a frequent complication in patients with thoracolumbar vertebral fracture (TVF). Transcutaneous electrical acustimulation (TEA) has been reported to effectively accelerate postoperative GI function recovery after abdominal surgery. This study aimed to investigate the effects of TEA on postoperative recovery and the associated mechanisms.

MATERIALS AND METHODS

A total of 81 patients with TVF who underwent elective posterior pedicle screw fixation surgery were randomized to receive TEA or sham-TEA. TEA at ST36 or sham-TEA at nonacupoints was performed for one hour twice daily, from 24 hours before surgery to postoperative day (POD) 3. The effects were then assessed in the form of a diary at different time points.

RESULTS

Compared with sham-TEA, TEA attenuated postoperative impairments associated with lower GI motility, including a reduction in time to defecation by 27.2% (p = 0.002 vs sham-TEA), time to first flatus by 17.2% (p = 0.027), an increase in the Bristol stool score (p = 0.014), and the number of spontaneous bowel movement (p = 0.009). TEA also relieved other GI symptoms including abdominal bloating on POD1 and POD4 (p < 0.001 and p = 0.001, respectively), straining during defecation (p < 0.001), and sensation of anorectal blockage during defecation (p = 0.02). Moreover, TEA reduced the visual analog scale wound pain score on POD1 (p = 0.026), POD2 (p < 0.001), and POD3 (p < 0.001), increased vagal activity, and decreased sympathetic activity (p < 0.001), in addition to suppressing the serum level of norepinephrine on both POD1 (p = 0.047) and POD4 (p = 0.036). TEA caused a higher decrease from POD1 to POD4 in serum interleukin-6 (p = 0.011, vs sham-TEA). The use of TEA was an independent predictor of shortened time to first defecation.

CONCLUSION

Noninvasive TEA at ST36, in comparison with sham-TEA, is effective in promoting postoperative recovery in patients with TVF by enhancing vagal and suppressing sympathetic activities.

CLINICAL TRIAL REGISTRATION

The study was retrospectively registered on www.chictr.org.cn (Chinese Clinical Trial Registry ChiCTR2300078195).

Efficacy and Safety of Noninvasive Electrical Neuromodulation for Treatment of Functional Constipation: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

BACKGROUND

Functional constipation (FC) is a prevalent disorder with large disease burden and high associated cost. Noninvasive electrical neuromodulation (NEN) has been studied for treatment of FC, but its overall efficacy and safety remain unclear. This meta-analysis evaluates the efficacy and safety of NEN for treatment of FC.

MATERIALS AND METHODS

A search of PubMed, Cochrane Library, Embase, and Web of Science data bases was completed for randomized controlled studies assessing the efficacy and safety of NEN in patients with FC through June 2024. We performed a meta-analysis using risk ratios (RRs) for dichotomous outcomes and mean differences (MDs) for continuous outcomes, with 95% CIs.

RESULTS

The analysis included eight randomized controlled trials with 1465 participants. Compared with sham interventions, NEN significantly increased the proportion of patients having ≥three spontaneous bowel movements per week (RR [95% CI] = 2.47 [1.79, 3.40], p < 0.00001), decreased the number of patients using laxative for FC (RR [95% CI] = 0.81 [0.69, 0.95], p = 0.01), decreased the overall constipation severity (MD [95% CI] = -0.58 [-0.81, -0.35], p < 0.00001), and improved the constipation-specific quality of life (MD [95% CI] = -0.24 [-0.32, -0.16], p < 0.00001). There was no significant difference in the frequency of adverse events between NEN and sham interventions (RR [95% CI] = 1.30 [0.77, 2.19], p = 0.32), and participant drop-out rate with NEN was lower (RR [95% CI] = 0.38 [0.17, 0.84], p = 0.02). Mechanistically, NEN was found to modulate the autonomic function (p < 0.00001) and improve the rectal sensation (p = 0.03).

CONCLUSIONS

NEN relieves constipation symptoms, improves quality of life, and reduces use of pharmacologic remedies in adults with FC. These effects seem to be modulated through improved autonomic function and rectal sensation. NEN is safe, well-tolerated, and has a high level of patient compliance.

Effects of stimulating single acupoint and combination acupoints on diabetic gastroparesis: A randomised controlled trial study

Background and aim

The most effective among the acupoints remains to be determined for treating diabetic gastroparesis (DGP). This study aimed to compare single and combination acupoints for their effectiveness in DGP.

Experimental procedure

A prospective, patient-assessor-blinded randomised controlled trial was designed to compare the efficacy of 8-week acupuncture at a single acupoint (Zhongwan, CV-12), combination acupoints (Zhongwan, CV-12 and Zusanli, ST-36), and a sham-acupoint, in 99 adults with DGP. The primary clinical outcome was measured using the Gastroparesis Cardinal Symptom Index (GCSI), while barium meal examination, fasting plasma glucose, the 2-h plasma glucose, short-form health survey (SF-36), and GCSI subscales were performed for evaluating secondary clinical outcomes. These results were analysed by two factorial analysis of variance (ANOVA) test, Chi-Square, Fisher Exact, Kruskal-Wallis tests and Tukey's Honest Significant Difference (HSD) test.

Results

After randomization, 97 patients completed the study. GCSI scores of all groups decreased during both post-treatment and the follow-up period, they were statistically significant compared to the baseline period (p < 0.01), but there was no significant difference among the groups (p > 0.05) during the post-treatment period. GCSI scores improved more in the combination acupoints group than in the single acupoint group which was better than the sham group after treatment. During the follow-up period, the same trend was observed.

Conclusions

Among patients with DGP, the combination acupoints were more beneficial compared with single and sham acupoints.

Trial registration number

NCT02452489.

Colonic Electrical Stimulation for Chronic Constipation: A Perspective Review

Chronic constipation affects around 20% of the population and there is no efficient solution. This perspective review explores the potential of colonic electric stimulation (CES) using neural implants and methods of bioelectronic medicine as a therapeutic way to treat chronic constipation. The review covers the neurophysiology of colonic peristaltic function, the pathophysiology of chronic constipation, the technical aspects of CES, including stimulation parameters, electrode placement, and neuromodulation target selection, as well as a comprehensive analysis of various animal models highlighting their advantages and limitations in elucidating the mechanistic insights and translational relevance for CES. Finally, the main challenges and trends in CES are discussed.

Transcutaneous electrical acupoint stimulation for cancer-related pain management in patients receiving chronic opioid therapy: a randomized clinical trial

PURPOSE

The opioid crisis resulting from its use disorder and overdose poses additional challenges for cancer pain management. The American Society of Clinical Oncology Practice Guideline recommends acupuncture therapy for the management of adult cancer-related pain (CRP), but the effectiveness of transcutaneous electrical acupoint stimulation (TEAS) on CRP remains uncertain.

METHODS

This 5-week prospective randomized clinical trial was conducted at 2 hospitals in China, and participants with CRP receiving chronic opioid therapy were randomized 1:1 into two groups between December 2014 and June 2018. The true TEAS group underwent 15 sessions of TEAS treatments over 3 consecutive weeks, while the control group received sham stimulation. The primary outcome was the numerical rating scale (NRS) score in the past 24h at week 3. The secondary outcomes included morphine equivalent daily dose, quality of life and adverse events.

RESULTS

A total of 159 participants were included in the modified intention-to-treat population. The baseline characteristics were similar in both groups. The mean NRS scores were 0.98 points at week 3 in the true TEAS group and 1.41 points in the sham group, with the mean difference between groups of -0.43 points (P < 0.001; OR = 0.68, P < 0.05). The proportion of patients with NRS reduction more than thirty percentage at week 3 was 50.00% in the true TEAS group and 35.44% in the sham group (RD = 0.15, P > 0.05; RR = 1.41, P > 0.05). No significant difference in pain intensity between the two groups was observed during the follow-up period without TEAS intervention (week 4, OR = 0.83, P > 0.05; week 5, OR = 0.83, P > 0.05). The Karnofsky Performance Status value suggested that patients in the true TEAS group experienced an improved quality of life (Between-group differences: week 3, 3.5%, P < 0.05; week 4, 4.6%, P < 0.001; week 5, 5.6%, P < 0.001).

CONCLUSIONS

The 3-week application of TEAS in patients with CRP receiving chronic opioid therapy resulted in a statistically significant reduction in pain scores, but the observed reduction was of uncertain clinical significance. The prolonged analgesic effect of TEAS was not confirmed in this trial.

CLINICALTRIAL

GOV: ChiCTR-TRC-13003803.

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.

Functional magnetic resonance imaging studies of acupuncture at ST36: a coordinate-based meta-analysis

Background

Functional magnetic resonance imaging (fMRI) has been widely used to investigate the brain effect of acupuncture point Stomach 36 (ST36, Zusanli). However, inconsistent results have hindered our understanding of the neural mechanisms of acupuncture at ST36.

Objective

To perform a meta-analysis of fMRI studies on acupuncture at ST36 to assess the brain atlas of acupuncture at ST36 from available studies.

Method

Based on a preregistered protocol in PROSPERO (CRD42019119553), a large set of databases was searched up to August 9, 2021, without language restrictions. Peak coordinates were extracted from clusters that showed significant signal differences before and after acupuncture treatment. A meta-analysis was performed using seed-based d mapping with permutation of subject images (SDM-PSI), a newly improved meta-analytic method.

Results

A total of 27 studies (27 ST36) were included. This meta-analysis found that ST36 could activate the left cerebellum, the bilateral Rolandic operculum, the right supramarginal gyrus, and the right cerebellum. Functional characterizations showed that acupuncture at ST36 was mainly associated with action and perception.

Conclusion

Our results provide a brain atlas for acupuncture at ST36, which, besides offering a better understanding of the underlying neural mechanisms, also provides the possibility of future precision therapies.

Nurse-delivered acupressure on early postoperative gastrointestinal function among patients undergoing colorectal cancer surgery

Objective

Postoperative gastrointestinal dysfunction occurred up to 25% of patients who undergo colorectal cancer surgery, which could cause severe complications and increase economic burden. This study aims to evaluate the effectiveness of nurse-delivered acupressure on early postoperative gastrointestinal function among patients undergoing colorectal cancer surgery.

Methods

A total of 112 adult patients (≥ 18 years) scheduled to receive colorectal cancer surgery were randomized into two groups. Acupressure was practiced at ST36 for five days after operation, while the control group used gently rubbing skin. Primary outcomes were the time to first passage of flatus and defecation, while the secondary outcomes were the degree of abdominal distention and bowel motility. The Student's t-test and Mann-Whitney U test or Chi-square test and regression analyses were used, while for repeated measures of outcomes, area under the curve (AUC) was compared between groups and subgroups.

Results

After adjusting for potential confounding variables, acupressure significantly shortened the time to have first flatus passage by 11.08 ​h (95%CI: -19.36 to -2.81; P ​< ​0.01). The first passage time of defecation (mean, 77.00 ​± ​36.27 ​h vs. 80.08 ​± ​28.88 ​h), abdominal distention (AUC, 5.68 ​± ​5.24 vs. 5.92 ​± ​4.03), and bowel motility (AUC, 12.09 ​± ​4.70 vs. 11.51 ​± ​3.00) in the intervention group had some improvement although the differences were not statistically significant (P ​> ​0.05).

Conclusions

This study indicated that acupressure done by trained nurses could be an effective and feasible solution to promote early gastrointestinal function recovery among patients undergoing colorectal cancer surgery.

Trial registration

Chinese Clinical Trial Registry (ChiCTR-IOR-17012460).

Roles of Heart Rate Variability in Assessing Autonomic Nervous System in Functional Gastrointestinal Disorders: A Systematic Review

Functional gastrointestinal disorders (FGID) and gastroesophageal reflux (GERD) disease affect a large global population and incur substantial health care costs. Impairment in gut-brain communication is one of the main causes of these disorders. The central nervous system (CNS) provides its inputs to the enteric nervous system (ENS) by modulating the autonomic nervous system (ANS) to control the gastrointestinal functions. Therefore, GERD and FGID's might be associated with autonomic dysfunction, which can be identified via heart rate variability (HRV). FGIDs may be treated by restoring the autonomic dysfunction via neuromodulation. This article reviews the roles of HRV in the assessment of autonomic function and dysfunction in (i) gastroesophageal reflux (GERD), and the following FGIDs: (ii) functional dyspepsia (FD) and gastroparesis, (iii) irritable bowel syndrome (IBS) and (iv) constipation. The roles of HRV in the assessment of autonomic responses to various interventions were also reviewed. We used PUBMED, Web of Science, Elsevier/Science direct and Scopus to search the eligible studies for each disorder, which also included the keyword 'heart rate variability'. The retrieved studies were screened and filtered to identify the most suitable studies using HRV parameters to associate the autonomic function with any of the above disorders. Studies involving both human and animal models were included. Based on analyses of HRV, GERD as well as the FGIDs were found to be associated with decreased parasympathetic activity and increased sympathetic nervous system activity with the autonomic balance shifted towards the sympathetic nervous system. In addition, the HRV methods were also reported to be able to assess the autonomic responses to various interventions (mostly neuromodulation), typically the enhancement of parasympathetic activity. In summary, GERD and FGIDs are associated with impaired autonomic dysfunction, mainly due to suppressed vagal and overactive sympathetic tone, which can be assessed noninvasively using HRV.

Transcutaneous Electrical Acupoint Stimulation Accelerates the Recovery of Patients Undergoing Laparoscopic Myomectomy: A Randomized Controlled Trial

Purpose

To evaluate transcutaneous electrical acupoint stimulation (TEAS) on the perioperative rehabilitation of patients undergoing laparoscopic myomectomy.

Patients and Methods

One hundred and five women undergoing laparoscopic hysteromyomectomy were randomly divided into TEAS group (Group T) and control group (Group C). Propofol and remifentanil were used to stabilize patient blood pressure and keep BIS between 40 and 60. Group T patients received TEAS at LI4/PC6 30 minutes before the operation and lasting until the end of anesthesia, followed by TEAS at ST36/SP6 for 30 minutes in PACU. All required indicators were recorded.

Results

Group T patients required lower dosages of remifentanil and vasoactive drugs, and had a reduced incidence of propofol injection pain and intraoperative hypotension compared to Group C. Group T also had a lower maximum NRS score in PACU, lower NRS scores at 1 hour and 24 hours, and a lower incidence of vomiting within 24 hours. In addition, the QoR-40 score for Group T at 24 hours after operation was higher in terms of physical comfort, emotional state, pain and total score.

Conclusion

TEAS can reduce the amount of anesthetic, maintain hemodynamic stability, reduce postoperative pain, reduce postoperative vomiting, enhance the recovery of gastrointestinal function, increase the quality of postoperative recovery and thus accelerate overall patient recovery.

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].

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.

Transcutaneous Electrical Acustimulation Improves Constipation by Enhancing Rectal Sensation in Patients With Functional Constipation and Lack of Rectal Sensation

INTRODUCTION

Reduced rectal sensation is involved in the pathophysiology of constipation. The aim of this study was to investigate the effects of transcutaneous electrical acustimulation (TEA) at acupuncture point ST36 on constipation and rectal sensation as well as autonomic functions in patients with constipation and reduced rectal sensation.

METHODS

In an acute study, anorectal motility and sensation tests were performed in constipation patients (N = 53) who were treated with TEA at ST36 or sham points. In a chronic study, patients (N = 18) underwent 2 weeks of TEA or sham-TEA in a crossover design.

RESULTS

Chronic TEA increased spontaneous bowel movements (3.72 vs 2.00 per week with sham-TEA, P < 0.0001) and significantly reduced constipation symptoms and increased quality of life in comparison with sham-TEA (P < 0.05). Acute TEA reduced the sensation threshold in response to rectal distention for the urge of defecation and maximum tolerable volume (P < 0.05, vs baseline); chronic TEA reduced the sensation thresholds for first sensation and desire of defecation, and decreased the threshold volume to an elicit rectal anal inhibitory reflex (P < 0.05). Both acute and chronic TEA increased parasympathetic activity (P < 0.05).

DISCUSSION

TEA at ST36 improves chronic constipation by enhancing rectal sensation possibly mediated by the reinforcement of parasympathetic activity in patients with functional constipation and reported lack/absence of rectal sensation.

Integrative effects of transcutaneous electrical acustimulation on abdominal pain, gastrointestinal motility, and inflammation in patients with early-stage acute pancreatitis

BACKGROUND/AIMS

Gastrointestinal (GI) dysmotility in acute pancreatitis (AP) aggravates inflammation and results in severe complications. This study aimed to explore effects and possible mechanisms of transcutaneous electrical acustimulation (TEA) on abdominal pain, GI dysmotility, and inflammation in AP patients.

METHODS

Forty-two AP patients were blindly randomized to receive TEA (n = 21) at acupoints PC6 and ST36 or Sham-TEA (n = 21) at sham points for 2 days. Symptom scores, gastric slow waves, autonomic functions (assessed by spectral analysis of heart rate variability), circulatory levels of motilin, ghrelin, and TNF-α were measured before and after the treatment. Sixteen healthy controls (HCs) were also included without treatment for the assessment of gastric slow waves and biochemistry.

KEY RESULTS

Compared with Sham-TEA, TEA decreased abdominal pain score (2.57 ± 1.78 vs. 1.33 ± 1.02, p < 0.05), bloating score (5.19 ± 1.21 vs. 0.76 ± 0.99, p < 0.001), the first defecation time (65.79 ± 19.51 h vs. 51.38 ± 17.19 h, p < 0.05); TEA, but not Sham-TEA, improved the percentage of normal gastric slow waves by 41.6% (p < 0.05), reduced AP severity score (5.52 ± 2.04 vs. 3.90 ± 1.90, p < 0.05) and serum TNF-α (7.59 ± 4.80 pg/ml vs. 4.68 ± 1.85 pg/ml, p < 0.05), and upregulated plasma ghrelin (0.85 ± 0.96 ng/ml vs. 2.00 ± 1.71 ng/ml, p = 0.001) but not motilin (33.08 ± 22.65 pg/ml vs. 24.12 ± 13.95 pg/ml, p > 0.05); TEA decreased sympathetic activity by 15.0% and increased vagal activity by 18.3% (both p < 0.05).

CONCLUSIONS & INFERENCES

TEA at PC6 and ST36 administrated at early stage of AP reduces abdominal pain, improves GI motility, and inhibits inflammatory cytokine, TNF-α, probably mediated via the autonomic and ghrelin mechanisms.

Transcutaneous auricular vagal nerve stimulation improves functional dyspepsia by enhancing vagal efferent activity

This study was designed to investigate whether transcutaneous auricular vagal nerve stimulation (taVNS) would be able to improve major pathophysiologies of functional dyspepsia (FD) in patients with FD. Thirty-six patients with FD (21 F) were studied in two sessions (taVNS and sham-ES). Physiological measurements, including gastric slow waves, gastric accommodation, and autonomic functions, were assessed by the electrogastrogram (EGG), a nutrient drink test and the spectral analysis of heart rate variability derived from the electrocardiogram (ECG), respectively. Thirty-six patients with FD (25 F) were randomized to receive 2-wk taVNS or sham-ES. The dyspeptic symptom scales, anxiety and depression scores, and the same physiological measurements were assessed at the beginning and the end of the 2-wk treatment. In comparison with sham-ES, acute taVNS improved gastric accommodation (P = 0.008), increased the percentage of normal gastric slow waves (%NSW, fasting: P = 0.010; fed: P = 0.007) and vagal activity (fasting: P = 0.056; fed: P = 0.026). In comparison with baseline, 2-wk taVNS but not sham-ES reduced symptoms of dyspepsia (P = 0.010), decreased the scores of anxiety (P = 0.002) and depression (P < 0.001), and improved gastric accommodation (P < 0.001) and the %NSW (fasting: P < 0.05; fed: P < 0.05) by enhancing vagal efferent activity (fasting: P = 0.015; fed: P = 0.048). Compared with the HC, the patients showed increased anxiety (P < 0.001) and depression (P < 0.001), and decreased gastric accommodation (P < 0.001) and %NSW (P < 0.001) as well as decreased vagal activity (fasting: P = 0.047). The noninvasive taVNS has a therapeutic potential for treating nonsevere FD by improving gastric accommodation and gastric pace-making activity via enhancing vagal activity.NEW & NOTEWORTHY Treatment of functional dyspepsia is difficult due to various pathophysiological factors. The proposed method of transcutaneous auricular vagal nerve stimulation improves symptoms of both dyspepsia and depression/anxiety, and gastric functions (accommodation and slow waves), possibly mediated via the enhancement of vagal efferent activity. This noninvasive and easy-to-implement neuromodulation method will be well received by patients and healthcare providers.

Auricular Vagal Nerve Stimulation Improves Constipation by Enhancing Colon Motility via the Central-Vagal Efferent Pathway in Opioid-Induced Constipated Rats

OBJECTIVES

Constipation and opioid-induced constipation (OIC) are common with limited treatment options. We investigated whether a noninvasive method of auricular vagal nerve stimulation (aVNS) could be used for treating OIC and explored its potential mechanisms and neural pathways in a rodent model of OIC.

MATERIALS AND METHODS

Sprague-Dawley were chronically implanted with one pair of auricular electrodes for aVNS. Sixteen rats were treated with loperamide for a week while another 16 rats received bilateral vagotomy, then randomly treated with aVNS or sham-aVNS for a week. In addition, eight normal rats were implanted with a polyethylene catheter in the proximal colon for assessing whole colon transit.

RESULTS

1) The number of fecal pellets and water content in feces increased after aVNS, compared with sham-aVNS. 2) aVNS accelerated colon transit and whole gut transit, compared with sham-aVNS. 3) In colon tissues, aVNS increased the protein expression of choline acetyltransferase, glial cell line-derived neurotrophic factor and the c-kit expression in myenteric interstitial cells of Cajal but decreased the protein expression of neural nitric oxide synthase (p < 0.05 for all, vs. sham-VNS). 4) The prokinetic effects of aVNS were abolished by both subdiaphragmatic vagotomy and atropine. 5) aVNS increased the c-fos expression in both nucleus tractus solitarius and dorsal motor nucleus of vagus, and increased vagal efferent activity (p < 0.05, vs. sham-VNS).

CONCLUSIONS

aVNS improves OIC by enhancing colon motility and restoring enteric neural functions mediated via the central and vagal efferent pathway.

Ameliorating Effects of Transcutaneous Electrical Acustimulation at Neiguan (PC6) and Zusanli (ST36) Acupoints Combined with Adaptive Biofeedback Training on Functional Outlet Obstruction Constipation

BACKGROUND

Stimulant laxatives are still considered the most common treatment for functional outlet obstruction constipation (FOOC). However, the effectiveness of laxatives is unsatisfactory, and the long-term use of laxatives may cause certain adverse events. With this in mind, it is, however, paramount that novel complementary treatment(s) and/or other forms of alternative medicine are adequately investigated.

AIMS

The study aims to explore the effects and potential mechanism(s) of transcutaneous electrical acustimulation (TEA) combined with adaptive biofeedback training (ABT) on FOOC.

METHODS

A total of forty-five patients with FOOC were recruited and were randomly assigned to receive either Macrogol 4000 Powder (MAC, 10 g bid) (group A, n = 15) only, ABT + MAC + Sham-TEA (group B, n = 15), or TEA + ABT + MAC (group C, n = 15) in a six-week study. Individual patients' constipation-symptoms (PAC-SYM) and constipation-quality of life (PAC-QOL) were both assessed and scored. Serum acetylcholine (Ach) and nitric oxide (NO) were measured from drawn blood samples while individual patients' heart rate variability (HRV) was calculated at baseline and after each corresponding therapy. Anorectal manometry and balloon expulsion test were both performed before and after treatment.

RESULTS

Firstly, participants in group C had significantly lower scores of PAC-SYM, PAC-QOL, and a decreased anal defecating pressure (ADP) as compared to participants in group B (all p < 0.050). These results, however, suggest the TEAs effect. Secondly, the low-frequency band (LF)/(LF + HF) ratio in groups B and C were decreased as compared to group A (p=0.037, p=0.010, respectively) regarding HRV. On the other hand, the high-frequency band (HF)/(LF + HF) ratio in groups B and C showed an opposite outcome. Finally, the serum Ach in groups B and C was significantly higher as compared to group A (p=0.023, p=0.012, respectively). Of significant importance, the serum NO in groups B and C were notably low as compared to group A (p=0.001, p < 0.001, respectively).

CONCLUSIONS

TEA, combined with ABT, effectively improves constipation symptoms as well as QOL in FOOC patients. It is, however, achieved by decreasing ADP, which mechanisms are mediated via the autonomic and enteric mechanisms.

Transcutaneous Electrical Acustimulation Improves Gastrointestinal Disturbances Induced by Transcatheter Arterial Chemoembolization in Patients With Liver Cancers

BACKGROUND

Gastrointestinal (GI) disturbances occur in patients who receive chemotherapy via transcatheter arterial chemoembolization (TACE) and could last for an extended period of time in some cases. Antiemetic drugs have a potential risk of developing hepatic failure and are ineffective for delayed nausea and emesis. Transcutaneous electrical acustimulation (TEA) has recently been reported to exert antiemetic and prokinetic effects, but it is unknown whether it has an ameliorating effect on TACE-induced GI disturbances.

AIM

This study was designed to evaluate effects and mechanisms of noninvasive TEA on GI symptoms in patients treated with TACE.

MATERIALS AND METHODS

Seventy-four patients with liver cancers (eighteen female; age 63.4 ± 1.1 years) scheduled for TACE were randomized to TEA (n = 37) or sham-TEA (n = 37). TEA was performed via acupoints, ST36 and PC6 using parameters previously optimized for GI motility (1 h, bid) from the postoperative day 0 (POD0) to POD2. Sham-TEA was performed using the same parameters via non-acupoints. Symptom questionnaires were completed daily. The electrogastrogram (EGG) and electrocardiogram (ECG) were recorded in the fasting state for 30 mins to assess gastric slow waves and autonomic functions, respectively, before and after the 3-day treatment.

RESULTS

1) In the acute phase (<24 h), TEA showed no effects on any of GI symptoms, compared with sham-TEA. 2) In the delayed phase (>24 h), TEA, compared with sham-TEA, decreased the percentage of patients who experienced nausea on POD3 (0% vs. 13.5%, p = 0.021), the nausea score on POD3 (p = 0.022), the anorexia score on POD2 (p = 0.040) and POD3 (p = 0.004), and the bloating score (POD1-3: p < 0.01). 3) In comparison with sham-TEA, TEA increased the number of spontaneous bowel movements (p = 0.001) and the Bristol score of the first stool (p = 0.014) and decreased the number of patients with the use of laxatives (p = 0.022). 4) Physiologically, the 3-day TEA but not sham-TEA increased the percentage of normal gastric slow waves (p < 0.001) and vagal activity (p = 0.006). The vagal activity was negatively correlated with the anorexia score (r = -0.267, p = 0.026). It was found that the sympathovagal ratio and tumor size>5 cm were independent risk factors predicting the occurrence of nausea in patients after TACE.

CONCLUSION

TEA improves major TACE-induced GI disturbances in the delayed phase, including nausea, bloating, impaired gastric pace-making activity, and constipation in patients with liver cancers via the autonomic pathway.