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

The effect of acupuncture on quality of life in patients with irritable bowel syndrome: A systematic review and meta-analysis

BACKGROUND

Acupuncture has been used to improve the quality of life (QoL) of patients in clinical settings. However, the effect of acupuncture on QoL in patients with irritable bowel syndrome (IBS) remains unclear. We conducted a systematic review and meta-analysis of randomized controlled trials (RCTs) to evaluate the effect of acupuncture on the QoL of patients with IBS.

METHOD

PubMed, Cochrane Central Register of Controlled Trials, Embase, and Web of Science were screened from inception to September 2023. RCTs published in English comparing acupuncture with sham acupuncture, usual care, pharmacological interventions, or other therapies were analyzed for QoL in patients with IBS. The primary outcome was QoL and secondary outcomes were the IBS-symptom severity scale (IBS-SSS) and abdominal pain. The Cochrane Collaboration recommendations were used to assess the risk of bias.

FINDINGS

Fourteen articles with 2,038 participants were included. The pooled result showed acupuncture can significantly improve the QoL of patients with IBS compared to the conventional treatment (MD = 6.62, 95% CI, 2.30 to 10.94, P<0.001, I2 = 72.45%). Additionally, acupuncture was superior to other interventions in relieving the symptoms' severity of IBS (MD = -46.58, 95% CI, -91.49 to -1.68, P<0.001, I2 = 90.76%). Nevertheless, acupuncture was not associated with abdominal pain reduction (MD = -0.35, 95% CI, -0.91 to 0.20, P = 0.21, I2 = 0.00%). Lower adverse events were observed in the acupuncture group. Thus, the quality of this study was relatively high.

CONCLUSION

The meta-analysis showed that acupuncture improves QoL and symptom severity in patients with IBS and that the optimal parameters for acupuncture to improve QoL in patients with IBS are 30 minutes of acupuncture per session, less than or equal to five sessions per week, and a 4-week course of treatment. However, more high-quality clinical trials are needed to provide stronger evidence.

Transcutaneous electrical acustimulation promotes wound healing in mice by modulating signaling molecules and mitochondria function

Previous research has identified a variety of factors that contribute to the development and maintenance of wounds. Concurrently, electroacupuncture has been demonstrated to facilitate wound healing. However, the effects of transcutaneous electrical acustimulation (TEA) on wound healing, as well as its relationship with key factors such as Wnt3a, TGF-β, Akt, c-Myc, VEGF-A, SP1, nitric oxide (NO), and mitochondrial function, remain largely unexplored. We hypothesize that TEA will activate the signaling factors and enhance mitochondrial functions to promote the repair of skin wounds in mice. An in vivo experimental study was conducted utilizing mouse models with skin wounds. The study comprised three groups: a TEA treatment with wound group, a skin wound model group, and a control group. Wound areas were measured by calculating the product of the length and width of each wound using calipers. Single-cell suspensions were prepared by excising the wound and the immediately surrounding tissue. These suspensions were stained with Trypan blue to assess cell viability, with specific probes to measure the rate of reactive oxygen species (ROS) positivity, and with reagents to quantify NO content. Western blotting (WB) was employed to evaluate protein levels associated with tissue changes, while quantitative polymerase chain reaction (qPCR) was used to assess RNA expression levels. Immunofluorescence staining was performed to visualize protein content and other relevant cellular structures within tissue sections. TEA exhibited anti-inflammatory properties and promoted wound healing in mice. Western blot analysis revealed that TEA enhanced the expression of proteins associated with Wnt3a, TGF-β, Akt, c-Myc, VEGF-A, and SP1 during the wound healing process. Immunofluorescence staining of tissue sections indicated that TEA upregulated the expression of COL1A1, MFN1, GRP75, GRP78, GRP75/ROS, GRP78/ROS, ISCU, and UCP1 while downregulating FIS1. Additionally, qPCR results demonstrated that TEA promoted the expression of IL-10 and miRNA205-5p while inhibiting MMP9 levels. TEA modulates various signaling molecules, influences chaperone proteins related to stress recovery responses, along with mitochondrial dynamics and metabolism.

Effect of transcutaneous electrical nerve stimulation based on wrist-ankle acupuncture theory for pain relief during colonoscopy without anesthesia: a randomized controlled trial

BACKGROUND

Colonoscopy is essential for diagnosing colorectal diseases but can cause pain during the procedure. This study explored the analgesic effects of transcutaneous electrical nerve stimulation based on wrist-ankle acupuncture theory (TENS-WAA) in colonoscopy without anesthesia.

METHODS

This prospective study included 120 participants undergoing colonoscopies without anesthesia. The trial group received low-frequency, high-intensity TENS-WAA adjusted to the maximum tolerable current, while the control group received minimal current. The primary outcome was the retrospective pain score on a visual analog scale (VAS). Secondary outcomes included time, heart rate, and credibility/expectancy questionnaire (CEQ) scores.

RESULTS

Participants who received TENS-WAA reported significantly lower pain VAS scores than the control group (estimated median difference -1.1, 95%CI -2 to -0.4; P = 0.002). Male participants in the trial group experienced significantly lower pain scores than the control group (mean difference -1.4, 95%CI -2.41 to -0.39; P = 0.008). The trial group showed significantly less variation in heart rates (P<0.001) and higher CEQ scores (P = 0.001) than the control group. No adverse events were reported.

CONCLUSION

TENS-WAA effectively reduced pain during colonoscopy without anesthesia, especially in male participants, providing a promising noninvasive analgesic method.

Prospective Evaluation of Autonomic Function and Intestinal Blood Flow in Health and Irritable Bowel Syndrome Shows Differences Limited to Patients With Constipation Predominance

BACKGROUND

Autonomic dysfunction may contribute to symptom generation in irritable bowel syndrome (IBS), possibly driven by psychological morbidity and activation of the hypothalamic-pituitary-adrenal axis. Previous data are conflicting, perhaps due to lack of accounting for differential bowel patterns in IBS (constipation vs. diarrhea) or by diverse methodologies used to measure autonomic function. Our aim was to determine if autonomic response differed between IBS subtypes and healthy controls.

METHODS

Forty female volunteers (20 IBS and 20 healthy) underwent comprehensive autonomic testing, fasting and postprandially, and in response to cold pressor and deep breathing challenges. Pulse transit time (PTT) and ultrasound measurements of intestinal blood flow were used as measures of systemic and local autonomic function, respectively. Outcomes were adjusted for baseline psychological comorbidities and gastric emptying (measured concurrently with scintigraphy).

KEY RESULTS

Findings, confined to IBS patients with predominant constipation (IBS-C), included (1) lower fasting and a trend to larger postprandial increase in superior mesenteric artery end-diastolic velocity; (2) lower fasting PTT, suggesting higher sympathetic tone, but no difference in postprandial PTT change; and (3) attenuated increase in postprandial aortic peak systolic velocity. Response to systemic autonomic challenges did not differ between IBS and health. Some psychological factors mediated differences between groups in the fasting, but not postprandial, state.

CONCLUSIONS AND INFERENCES

IBS-C patients display systemic and local autonomic imbalance providing some support for recent therapies aimed at modulating autonomic state specifically in this patient group (e.g., acustimulation).

The interplay between gut microbiota composition and dementia

Recently, researchers have been interested in the potential connection between gut microbiota composition and various neuropsychological disorders. Dementia significantly affects the socioeconomics of families. Gut microbiota is considered as a probable factor in its pathogenesis. Multiple bacterial metabolites such as short-chain fatty acids, lipopolysaccharides, and various neurotransmitters that are responsible for the incidence and progression of dementia can be produced by gut microbiota. Various bacterial species such as Bifidobacterium breve, Akkermansia muciniphila, Streptococcus thermophilus, Escherichia coli, Blautia hydrogenotrophica, etc. are implicated in the pathogenesis of dementia. Gut microbiota can be a great target for imitating or inhibiting their metabolites as an adjunctive therapy based on their role in its pathogenesis. Therefore, some diets can prevent or decelerate dementia by altering the gut microbiota composition. Moreover, probiotics can modulate gut microbiota composition by increasing beneficial bacteria and reducing detrimental species. These therapeutic modalities are considered novel methods that are probably safe and effective. They can enhance the efficacy of traditional medications and improve cognitive function.

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.

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.

Efficacy and Safety of Transcutaneous Auricular Vagus Nerve Stimulation in Patients With Constipation-Predominant Irritable Bowel Syndrome: A Single-Center, Single-Blind, Randomized Controlled Trial

INTRODUCTION

Transcutaneous auricular vagus nerve stimulation (taVNS) is a promising therapy for irritable bowel syndrome (IBS). The aims of this clinical trial were to evaluate the influence of taVNS on autonomic functions, rectal sensation, and acetylcholine (Ach) levels and to explore potential mechanisms involving gut microbiota and metabolic profiles.

METHODS

This study was a single-center, single-blind, randomized controlled trial executed at the First Affiliated Hospital of USTC, Anhui, China. Individual patients' constipation-predominant IBS (IBS-C)-related symptoms and mental health were assessed and scored using questionnaires at baseline and at week 4. Levels of serum Ach and nitric oxide, anorectal manometry, and heart rate variability were assessed both before and after the therapy. Fecal samples from each group were assessed to compare the gut microbiota, short-chain fatty acids, and gut microbiota-derived tryptophan metabolites.

RESULTS

Between September 2023 and May 2024, 40 patients (n = 20 in both taVNS and sham-taVNS groups) completed the 4-week study by performing an intention-to-treat analysis. No differences in all parameters between taVNS and sham-taVNS groups at the baseline were found. The taVNS significantly improved the visual analog scale score ( P < 0.001), IBS Severity Scoring System score ( P < 0.001), weekly frequency of spontaneous bowel movements ( P < 0.001), weekly frequency of complete spontaneous bowel movements ( P = 0.004), Bristol Stool Form Scale score ( P < 0.001), Hamilton Anxiety Scale score ( P < 0.001), Hamilton Depression Scale score ( P < 0.001), and IBS Quality of Life score ( P < 0.001). Furthermore, taVNS improved rectal sensation in patients with IBS-C, including improvements in the threshold volume for initial sensation ( P = 0.033), urge to defecate ( P = 0.022), and rectoanal inhibitory reflex ( P = 0.002). Moreover, taVNS elevated serum levels of Ach ( P = 0.005) and reduced nitric oxide ( P = 0.016) while also enhancing vagal activity ( P < 0.001) as determined by spectral analysis of heart rate variability. Three patients in the taVNS group and 2 in the control group had adverse consequences, which were manageable. In addition, taVNS led to a significant rise in the level of the genus Bifidobacterium ( P = 0.038) and increased levels of acetic ( P = 0.003), butyric ( P = 0.011), and propionic ( P = 0.005) acids. It also decreased tryptophan metabolism content, including 3-hydroxyanthranilic acid ( P = 0.007), anthranilic acid ( P = 0.026), and L-tryptophan ( P = 0.002).

DISCUSSION

The study manifested that noninvasive taVNS effectively improved constipation and abdominal pain symptoms in patients with IBS-C. The alleviation of IBS-C symptoms may be attributed to the integrative effects of taVNS on rectal functions, mediated through vagal, cholinergic, and multiomics mechanisms.

Comparisons of different electrical stimulation modalities for treating visceral pain in a rodent model of irritable bowel syndrome

The purpose of this study was to investigate the effects of different electrical stimulation methods (bilateral electroacupuncture (BEA), unilateral EA (UEA), transcutaneous electrical acustimulation (TEA, stimulation via surface electrodes placed at acupoints), and sacral nerve stimulation (SNS)) on visceral pain in a rodent model of irritable bowel syndrome (IBS). Ten-day-old male and female pups were treated with 0.2 ml of 0.5% acetic acid (AA) solution. Visceral sensitivity was assessed using an electromyogram (EMG) in response to graded colorectal distension. In the first experiment, bilateral EA at ST36 acupoint was performed with different parameters in male rats to determine the best stimulation parameters. In the second experiment, male rats were randomly assigned into the Sham, BEA, UEA, TEA, and SNS groups to determine the best stimulation method. Lastly, the AA-treated female rats were randomly assigned into the BEA and sham groups to investigate a potential treatment difference between the sexes. Two distinct sets of stimulation parameters were used: Set 1 (100 Hz, 0.5 ms pulse width, 0.1 s ON, 0.4 s OFF, 0.4-3.0 mA current) and Set 2 (25 Hz, 0.5 ms pulse width, 2 s ON, 3 s OFF, 0.4-3.0 mA current).Results (1) The parameter set of 100Hz was found to be most effective in reducing visceral pain. (2) Both acute UEA and TEA effectively relieved visceral pain, whereas acute SNS did not exhibit such an effect. (3) Acute BEA improved visceral pain in both male and female rats.Conclusions These findings suggest that transcutaneous ST36 stimulation is as effective as direct ST36 stimulation and unilateral ST36 stimulation is comparable to bilateral stimulation. Development of a novel therapy using unilateral transcutaneous ST36 stimulation is warranted.

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.

Ameliorating effects of transcutaneous auricular vagus nerve stimulation on a mouse model of constipation-predominant irritable bowel syndrome

Limited treatment options have been shown to alter the natural course of constipation-predominant irritable bowel syndrome (IBS-C). Therefore, safer and more effective approaches are urgently needed. We investigated the effects of transcutaneous auricular vagus nerve stimulation (taVNS) in a mouse model of IBS-C. In the current study, C57BL/6 mice were randomly divided into normal control, IBS-C model control, sham-electrostimulation (sham-ES), taVNS, and drug treatment groups. The effects of taVNS on fecal pellet number, fecal water content, and gastrointestinal transit were evaluated in IBS-C model mice. We assessed the effect of taVNS on visceral hypersensitivity using the colorectal distention test. 16S rRNA sequencing was used to analyze the fecal microbiota of the experimental groups. First, we found that taVNS increased fecal pellet number, fecal water content, and gastrointestinal transit in IBS-C model mice compared with the sham-ES group. Second, taVNS significantly decreased the abdominal withdrawal reflex (AWR) score compared with the sham-ES group, thus relieving visceral hyperalgesia. Third, the gut microbiota outcomes showed that taVNS restored Lactobacillus abundance while increasing Bifidobacterium probiotic abundance at the genus level. Notably, taVNS increased the number of c-kit-positive interstitial cells of Cajal (ICC) in the myenteric plexus region in IBS-C mice compared with the sham-ES group. Therefore, our study indicated that taVNS effectively ameliorated IBS-C in the gut microbiota and ICC.

Transcutaneous Auricular Vagal Nerve Stimulation Is Effective for the Treatment of Functional Dyspepsia: A Multicenter, Randomized Controlled Study

INTRODUCTION

Vagal nerve stimulation (VNS) can be used to modulate gastrointestinal motility, inflammation, and nociception. However, it remains unclear whether VNS is effective in adult patients with functional dyspepsia (FD). We investigated the effectiveness of transcutaneous auricular VNS (taVNS) in patients with FD.

METHODS

Consecutive patients with FD meeting Rome IV criteria with modified FD Symptom Diary score ≥10 were enrolled. Patients were randomly allocated to 10-Hz taVNS (V10 group), 25-Hz taVNS (V25 group), or sham group, with 30 minutes of treatment twice a day for 4 weeks. The primary outcome was the response rate at week 4, defined as the proportion of patients whose modified FD Symptom Diary score was reduced ≥5 when compared with the baseline. Secondary outcomes included adequate relief rate and adverse events.

RESULTS

A total of 300 patients were randomized to V10 (n = 101), V25 (n = 99), and sham groups (n = 100). After 4 weeks of treatment, V10 and V25 groups had a higher response rate (81.2% vs 75.9% vs 47%, both P < 0.001) and adequate relief rate (85.1% vs 80.8% vs 67%, both P < 0.05) compared with the sham group. There was no significant difference between V10 and V25 in response rate and adequate relief rate (both P > 0.05). The efficacy of taVNS (both 10 and 25 Hz) lasted at week 8 and week 12 during follow-up period. Adverse events were all mild and comparable among the 3 groups (1%-3%).

DISCUSSION

Our study firstly showed that 4-week taVNS (both 10 and 25 Hz) was effective and safe for the treatment of adult FD ( clinicaltrials.gov number: NCT04668534).

Fenchone Ameliorates Constipation-Predominant Irritable Bowel Syndrome via Modulation of SCF/c-Kit Pathway and Gut Microbiota

In this study we sought to elucidate the therapeutic effects of fenchone on constipation-predominant irritable bowel syndrome (IBS-C) and the underlying mechanisms. An IBS-C model was established in rats by administration of ice water by gavage for 14 days. Fenchone increased the reduced body weight, number of fecal pellets, fecal moisture, and intestinal transit rate, and decreased the enhanced visceral hypersensitivity in the rat model of IBS-C. In addition, fenchone increased the serum content of excitatory neurotransmitters and decreased the serum content of inhibitory neurotransmitters in the IBS-C rat model. Meanwhile, western blot and immunofluorescence experiments indicated that fenchone increased the expressions of SCF and c-Kit. Furthermore, compared with the IBS-C model group, fenchone increased the relative abundance of Lactobacillus, Blautia, Allobaculum, Subdoligranulum, and Ruminococcaceae_UCG-008, and reduced the relative abundance of Bacteroides, Enterococcus, Alistipes, and Escherichia-Shigella on the genus level. Overall, fenchone ameliorates IBS-C via modulation of the SCF/c-Kit pathway and gut microbiota, and could therefore serve as a novel drug candidate against IBS-C.

Transcutaneous Electrical Acustimulation Improves Constipation Symptoms and Accelerates Colonic Transit in Patients With Slow Transit Constipation Through Autonomic Mechanism

OBJECTIVES

Nearly half of patients with slow transit constipation (STC) are not completely satisfied with their traditional remedies. We aimed to evaluate the therapeutic value and possible involved mechanism of transcutaneous electrical acustimulation (TEA) at ST36 in patients with STC.

MATERIALS AND METHODS

Seventy patients with STC were randomly divided into TEA (n = 35) and sham-TEA (n = 35) to undergo a two-week treatment with TEA at ST36 or sham point. After the two-week treatment, 18 patients from each group randomly underwent a few physiological tests, including the electrocardiogram (ECG), anorectal manometry, colon transit test, and blood drawing. After a two-week washout period, TEA was performed in both groups for two weeks.

RESULTS

Spontaneous bowel movements per week were increased, and scores of constipation symptoms were decreased, after a two-week blind TEA but not sham-TEA, which were sustained after a two-week washout period. Improvement in quality of life and psychologic states also was observed with blind TEA treatment. Mechanistically, the two-week blind TEA accelerated colon transit assessed by barium strip excretion rate (the effect was sustained after a two-week washout period), enhanced vagal nerve activity evaluated by the spectral analysis of heart rate variability derived from the ECG, and decreased circulating vasoactive intestinal peptide.

CONCLUSIONS

Noninvasive TEA relieves constipation and improves quality of life and psychologic states in patients with STC, and the effects are sustained for ≥two weeks. The therapeutic effects of TEA may be attributed to the acceleration of colon transit and decrease of vasoactive intestinal peptide mediated through the vagal mechanism.

Effects of chronic unpredictable mild stress on gut sensation and function in male mice

Stress has been linked to the development of irritable bowel syndrome (IBS), and various methods have been explored to model IBS in combination with other stimuli. However, it remains unclear whether stress alone can induce IBS in animals. This study aimed to investigate the impact of chronic unpredictable mild stress (CUMS) on gastrointestinal sensation and function in mice and assess the potential of CUMS as a modeling approach for IBS. To evaluate the mice's behavior, we conducted open field test, sucrose preference test and weighed the mice, revealing that CUMS indeed induced anxiety and depression in the mice and caused weight loss. Further analyses, including fecal analysis, a total gastrointestinal transport test, and a colon propulsion test, demonstrated that CUMS led to abnormal defecation and disruptions in gastrointestinal motility in the mice. Additionally, the abdominal withdrawal reflex test indicated an increase in visceral sensitivity in CUMS-exposed mice. Histological examination using hematoxylin and eosin staining revealed no significant histological alterations in the colons of CUMS-exposed mice, but it did show a minor degree of inflammatory cell infiltration. In summary, the findings suggest that CUMS can replicate IBS-like symptoms in mice, offering a novel top-down approach to modeling IBS.

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.

Transcutaneous electrical stimulation for gastrointestinal motility disorders

BACKGROUND/PURPOSE

Gastrointestinal (GI) dysmotility is categorized by muscle or nerve dysfunctions in any portion of the GI tract, which leads to abnormalities in GI motor and sensory function. Symptoms may vary depending on the organ affected and can be debilitating. Treatment usually involves diet and lifestyle changes. Pharmacotherapy is limited in effectiveness with various side effects. Transcutaneous electrical stimulation (TES), a noninvasive, needleless technique that provides electrical stimulation using cutaneous non-needle electrodes, has become increasingly popular. It has been shown to be beneficial in treating GI motility disorders.

METHODS

This review paper navigates through the different TES techniques, including transcutaneous peripheral nerve (vagal/sacral/tibial nerves) electrical stimulation, transcutaneous electrical acustimulation (stimulation via acupuncture point), transcutaneous interferential current therapy, and transcutaneous electrical nerve stimulation.

KEY RESULTS

As we delve deeper, we explore the promising effects of TES on dysphagia, gastroesophageal reflux disease, functional dyspepsia, gastroparesis, postoperative ileus, constipation, and irritable bowel syndrome. The literature at hand speaks volumes about the therapeutic prowess of this noninvasive technique.

CONCLUSION & INFERENCES

The time is ripe to evaluate further the full therapeutic potential of TES, a noninvasive, nonpharmaceutical, nonsurgical, and home-based self-administrative technique in managing GI motility disorders.

Review article: Functional dyspepsia and pregnancy-Effects and management in a special population

BACKGROUND

Around 10% of Americans meet the Rome IV criteria for functional dyspepsia (FD), with a significantly higher rate in women. FD also has a higher prevalence in women below the age of 50, suggesting that women who are affected are likely to be of reproductive age. Unfortunately, there is a lack of research or evidence-based guidelines on managing FD in pregnancy.

AIMS AND METHODS

To address this issue, we aimed to perform a systematic review of the interactions between FD and pregnancy and managing pre-existing FD in the peripartum and post-partum phases using current lifestyle, pharmacological, non-pharmacological and alternative medicine interventions.

RESULTS

Due to the lack of Rome IV FD-specific data in pregnancy, we instead performed a narrative review on how existing FD interventions could be extrapolated to the pregnant population. Where possible we use the highest level of available evidence or official guidelines to answer these questions, which often involves synthesising treatment and safety evidence of these interventions in other diseases during pregnancy. Finally, we highlight current substantial knowledge gaps requiring further research for the safe management of a pregnant patient with pre-existing FD.

CONCLUSIONS

Overall, despite the paucity of knowledge of treating FD during pregnancy, providers can mitigate this uncertainty by planning ahead with the patient. Patients should ideally minimise treatment until after breastfeeding. However, interdisciplinary resources are available to ensure that minimal-risk interventions are maximised, while interventions with more risks, if necessary, are justifiable by both the patient and the care team. Future investigations should continue to elicit the mechanistic relationship between FD and pregnancy while cautiously expanding prospective research on promising and safe therapies in pregnant patients with pre-existing FD.

Update on treatment of abdominal pain in irritable bowel syndrome: A narrative review

The objectives of this narrative review are to update readers on the current state-of-the-art regarding diverse approaches for the treatment of pain, global symptoms, or adequate relief in irritable bowel syndrome (IBS). The article appraises medications, dietary interventions including low fermentable oligosaccharides, disaccharides, and monosaccharides and polyols (FODMAP) diet, fecal microbial transplantation (FMT), electrical approaches, and behavioral therapies including cognitive behavioral therapy (CBT), gut-directed hypnotherapy (GDH), mindfulness, and open-label placebo. Current evidence demonstrates only modest benefit in global IBS symptoms and pain relief. A future approach that identifies pathophysiological mechanisms of IBS through validated biomarkers has the potential to individualize treatment of patients rather than sequential therapeutic trial and error approaches.

Electrical devices for functional visceral pain

Several studies have documented correction of dysmotility in several regions of the gastrointestinal tract based on electrical stimulation of extrinsic nerves supplying those regions. In this issue of Neurogastroenterology and Motility, Ma et al. (2023) document the effect of transcutaneous neuromodulation applied by acustimulation at ST36 for ineffective esophageal motility in patients with gastroesophageal reflux disease. In addition to motor effects, there were also significant effects on GERD symptoms, raising the question whether extrinsic electrical nerve stimulation of the gut can reduce symptoms through effects that target sensation. This brief review summarizes evidence regarding the application of electrical acustimulation, transauricular electrical stimulation, and sacral electrical or magnetic stimulation to reduce abdominal or pelvic pain.

Electrophysiology as a Tool to Decipher the Network Mechanism of Visceral Pain in Functional Gastrointestinal Disorders

Abdominal pain, including visceral pain, is prevalent in functional gastrointestinal (GI) disorders (FGIDs), affecting the overall quality of a patient's life. Neural circuits in the brain encode, store, and transfer pain information across brain regions. Ascending pain signals actively shape brain dynamics; in turn, the descending system responds to the pain through neuronal inhibition. Pain processing mechanisms in patients are currently mainly studied with neuroimaging techniques; however, these techniques have a relatively poor temporal resolution. A high temporal resolution method is warranted to decode the dynamics of the pain processing mechanisms. Here, we reviewed crucial brain regions that exhibited pain-modulatory effects in an ascending and descending manner. Moreover, we discussed a uniquely well-suited method, namely extracellular electrophysiology, that captures natural language from the brain with high spatiotemporal resolution. This approach allows parallel recording of large populations of neurons in interconnected brain areas and permits the monitoring of neuronal firing patterns and comparative characterization of the brain oscillations. In addition, we discussed the contribution of these oscillations to pain states. In summary, using innovative, state-of-the-art methods, the large-scale recordings of multiple neurons will guide us to better understanding of pain mechanisms in FGIDs.

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].

Similarities between Ashi acupoints and myofascial trigger points: Exploring the relationship between body surface treatment points

Although acupuncture points and myofascial trigger points (TPs) are based in different medical fields, the two points share important attributes. We explored the relationship between acupuncture points and TPs based on their characteristics and the results of previous studies. We outlined the relationship between acupuncture points and TPs by examining their similarities and differences. Among the acupuncture point subgroups, TPs mostly corresponded to Ashi points. Based on the common features of TPs and Ashi points, we suggest that TPs are more closely related to Ashi points than to other acupoints. However, TPs also share some features, such as pain indication and location, with classical acupuncture points (CA) and extra acupuncture points (EA), which makes it difficult to elucidate their relationship with other subgroups. Therefore, we suggest to understand the relationship of CAs, EAs, Ashi points, and TPs. In this report, we concluded that concerning muscular pain symptoms Ashi points and TPs are indistinguishable.