Long-Pulse Gastric Electrical Stimulation Repairs Interstitial Cells of Cajal and Smooth Muscle Cells in the Gastric Antrum of Diabetic Rats

Electroceuticals: Unlocking the promise of therapies

OBJECTIVES

Electroceuticals refers to the constantly growing disciplines of bioelectric and bioelectronic medication. These include a broad variety of devices that have been invented and are now being utilized in medical implants, wearable medical electronics, and bioelectronics. The primary aim of this study is to encompass several facets of electroceuticals, their applications, and recent advancements in the field of medical challenges.

EVIDENCE ACQUISITIONS

A complete literature study was conducted, which included a comprehensive review of globally recognized scientific research databases.

RESULTS

The progressive refinement and diminution of technology, in conjunction with swift advancements in comprehending the role of electrical pathways in the human body, have rendered it progressively viable to manipulate these pathways for therapeutic purposes.

DISCUSSION AND CONCLUSION

Electrical stimulation impacts and modifies biological functioning and pathological processes in the body. In the contemporary era of medicine, health care practitioners from a variety of fields utilize electricity to cure disease or injury or to assess and diagnose using a variety of electrically driven medical tools.

Calcium wave dynamics in the embryonic mouse gut mesenchyme: impact on smooth muscle differentiation

Intestinal smooth muscle differentiation is a complex physico-biological process involving several different pathways. Here, we investigate the properties of Ca2+ waves in the developing intestinal mesenchyme using GCamp6f expressing mouse embryos and investigate their relationship with smooth muscle differentiation. We find that Ca2+ waves are absent in the pre-differentiation mesenchyme and start propagating immediately following α-SMA expression. Ca2+ waves are abrogated by CaV1.2 and gap-junction blockers, but are independent of the Rho pathway. The myosine light-chain kinase inhibitor ML-7 strongly disorganized or abolished Ca2+ waves, showing that perturbation of the contractile machinery at the myosine level also affected the upstream Ca2+ handling chain. Inhibiting Ca2+ waves and contractility with CaV1.2 blockers did not perturb circular smooth muscle differentiation at early stages. At later stages, CaV1.2 blockers abolished intestinal elongation and differentiation of the longitudinal smooth muscle, leading instead to the emergence of KIT-expressing interstitial cells of Cajal at the gut periphery. CaV1.2 blockers also drove apoptosis of already differentiated, CaV1.2-expressing smooth muscle and enteric neural cells. We provide fundamental new data on Ca2+ waves in the developing murine gut and their relation to myogenesis in this organ.

Common Pathophysiological Mechanisms and Treatment of Diabetic Gastroparesis

Diabetic gastroparesis (DGP) is a common complication of diabetes mellitus, marked by gastrointestinal motility disorder, a delayed gastric emptying present in the absence of mechanical obstruction. Clinical manifestations include postprandial fullness and epigastric discomfort, bloating, nausea, and vomiting. DGP may significantly affect the quality of life and productivity of patients. Research on the relationship between gastrointestinal dynamics and DGP has received much attention because of the increasing prevalence of DGP. Gastrointestinal motility disorders are closely related to a variety of factors including the absence and destruction of interstitial cells of Cajal, abnormalities in the neuro-endocrine system and hormone levels. Therefore, this study will review recent literature on the mechanisms of DGP and gastrointestinal motility disorders as well as the development of prokinetic treatment of gastrointestinal motility disorders in order to give future research directions and identify treatment strategies for DGP.

Neuromodulation and Functional Gastrointestinal Disease

INTRODUCTION

Functional gastrointestinal disorders (FGIDs) are common, and they severely impair an individual's quality of life. The mechanism of pathogenesis and the effective treatments for FGIDs remain elusive. Neuromodulation-a relatively new treatment-has exhibited a good therapeutic effect on FGIDs, although there are different methods for different symptoms of FGIDs.

MATERIALS AND METHODS

We used PubMed to review the history of neuromodulation for the treatment of FGIDs and to review several recently proposed neuromodulation approaches with improved effects on FGIDs.

CONCLUSION

Electroacupuncture, transcutaneous electroacupuncture, transcutaneous auricular vagal nerve stimulation, sacral nerve stimulation (SNS) (which relies on vagal nerve stimulation), and gastric electrical stimulation (which works through the modulation of slow waves generated by the interstitial cells of Cajal), in addition to the noninvasive neurostimulation alternative approach method of SNS-tibial nerve stimulation and transcutaneous electrical stimulation (which is still in its infancy), are some of the proposed neuromodulation approaches with improved effects on FGIDs. This review has discussed some critical issues related to the selection of stimulation parameters and the underlying mechanism and attempts to outline future research directions backed by the existing literature.

Gastric Electrical Stimulation for the Treatment of Gastroparesis or Gastroparesis-Like Symptoms: A Systemic Review and Meta-Analysis

BACKGROUND

The effects of gastric electrical stimulation are not fully understood. We aimed to assess the efficacy of gastric electrical stimulation (GES) for patients with gastroparesis and gastroparesis-like symptoms.

MATERIALS AND METHODS

We searched PubMed, Scopus, Cochrane, Web of Science, Embase, and Science Direct to identify controlled trials and cohort studies. We used random effects models to estimate pooled effects. A total of nine studies met the criteria and were included for the final qualitative synthesis and the quantitative analysis. We examined the mean absolute differences (MD) and 95% CIs.

RESULTS

Nine studies (n = 730) met the criteria and were included for the final qualitative synthesis and the quantitative analysis. There was significant improvement in gastrointestinal (GI) total symptom score (TSS) with the GES group compared with controls during the randomized blind trials. This effect was sustained at 12 months after treatment compared with before treatment (MD = -6.07; 95% CI, -4.5 to -7.65; p < 0.00001). The pooled effect estimate showed a significant improvement in frequency of weekly vomiting episodes at 12 months compared with before treatment (MD = -15.59; 95% CI, -10.29 to -20.9; p < 0.00001).

CONCLUSION

GES appears beneficial, with significant improvement in GI TSS, weekly vomiting frequency, gastric emptying study, and quality of life.

A systematic review on diagnosis and treatment of gastrointestinal diseases by magnetically controlled capsule endoscopy and artificial intelligence

Background

Magnetically controlled capsule endoscopy (MCCE) is a non-invasive, painless, comfortable, and safe equipment to diagnose gastrointestinal diseases (GID), partially overcoming the shortcomings of conventional endoscopy and wireless capsule endoscopy (WCE). With advancements in technology, the main technical parameters of MCCE have continuously been improved, and MCCE has become more intelligent.

Objectives

The aim of this systematic review was to summarize the research progress of MCCE and artificial intelligence (AI) in the diagnosis and treatment of GID.

Data Sources and Methods

We conducted a systematic search of PubMed and EMBASE for published studies on GID detection of MCCE, physical factors related to MCCE imaging quality, the application of AI in aiding MCCE, and its additional functions. We synergistically reviewed the included studies, extracted relevant data, and made comparisons.

Results

MCCE was confirmed to have the same performance as conventional gastroscopy and WCE in detecting common GID, while it lacks research in detecting early gastric cancer (EGC). The body position and cleanliness of the gastrointestinal tract are the main factors affecting imaging quality. The applications of AI in screening intestinal diseases have been comprehensive, while in the detection of common gastric diseases such as ulcers, it has been developed. MCCE can perform some additional functions, such as observations of drug behavior in the stomach and drug damage to the gastric mucosa. Furthermore, it can be improved to perform a biopsy.

Conclusion

This comprehensive review showed that the MCCE technology has made great progress, but studies on GID detection and treatment by MCCE are in the primary stage. Further studies are required to confirm the performance of MCCE.

Physical organogenesis of the gut

The gut has been a central subject of organogenesis since Caspar Friedrich Wolff’s seminal 1769 work ‘De Formatione Intestinorum’. Today, we are moving from a purely genetic understanding of cell specification to a model in which genetics codes for layers of physical–mechanical and electrical properties that drive organogenesis such that organ function and morphogenesis are deeply intertwined. This Review provides an up-to-date survey of the extrinsic and intrinsic mechanical forces acting on the embryonic vertebrate gut during development and of their role in all aspects of intestinal morphogenesis: enteric nervous system formation, epithelium structuring, muscle orientation and differentiation, anisotropic growth and the development of myogenic and neurogenic motility. I outline numerous implications of this biomechanical perspective in the etiology and treatment of pathologies, such as short bowel syndrome, dysmotility, interstitial cells of Cajal-related disorders and Hirschsprung disease.

Atractylodes chinensis volatile oil up-regulated IGF-1 to improve diabetic gastroparesis in rats

Objectives

Diabetic gastroparesis (DGP) is one of the main complications of diabetes, and more than half of diabetes cases are accompanied by gastroparesis. This study aims to explore the effect of Atractylodes chinensis volatile oil (ACVO) on DGP rats.

Materials and Methods

The rats were injected with STZ combined with a high-sugar and high-fat diet in an irregular manner to establish the DGP model. ACVO at different doses (9.11 mg/kg, 18.23 mg/kg, and 36.45 mg/kg) were given by intragastric administration. A mixture of cisapride and metformin was used as the positive control. At the end of the experiment, gastric emptying and intestinal propulsion were determined. Then the tissue samples and blood were taken from each group for serum analysis, western blot and immunopathological examination.

Results

After treatment with ACVO, body weight increased and blood glucose decreased when compared with rats in the DGP group. Gastric emptying and intestinal propulsion were accelerated, and gastric acid secretion increased. The serum insulin-like growth factor-1 (IGF-1) level was increased. Protein expressions and positive cells of IGF-1 receptor (IGF-1R), acetylcholine transferase (CHAT), and stem cell factors (SCF) in the stomach were significantly increased determined by western blot and immunofluorescence staining. The morphology and the number of interstitial cells of Cajal (ICCs) in the stomach were restored, determined by hematoxylin and eosin staining and immunohistochemical staining, respectively.

Conclusion

ACVO effectively alleviated DGP in rats, and its mechanism may be related to the up-regulation of IGF-1/IGF-1R signaling.

Molecular Mechanisms of Hawthorn Extracts in Multiple Organs Disorders in Underlying of Diabetes: A Review

Diabetes mellitus (DM) is one of the most important metabolic disorders associated with chronic hyperglycemia and occurs when the body cannot manage insulin secretion, insulin action, or both. Autoimmune destruction of pancreatic beta cells and insulin resistance are the major pathophysiological factors of types 1 and 2 of DM, respectively. Prolonged hyperglycemia leads to multiple organs dysfunctions, including nephropathy, neuropathy, cardiomyopathy, gastropathy, and micro- and macrovascular disorders. The basis of the metabolic abnormalities in carbohydrate, fat, and protein in diabetes is insufficient action of insulin on various target tissues. Medicinal plants are rich sources of bioactive chemical compounds with therapeutic effects. The beneficial effects of leaves, fruits, and flowers extracts of Crataegus oxyacantha, commonly called hawthorn, belonging to the Rosaceae family, are widely used as hawthorn-derived medicines. Data in this review have been collected from the scientific articles published in databases such as Science Direct, Scopus, PubMed, Web of Science, and Scientific Information Database from 2000 to 2021. Based on this review, hawthorn extracts appear both therapeutic and protective effects against diabetic-related complications in various organs through molecular mechanisms, such as decreasing triglyceride, cholesterol, very low density lipoprotein and increasing the antioxidant activity of superoxide dismutase, catalase, glutathione peroxidase, total antioxidant capacity, decreasing malondialdehyde level, and attenuating tumor necrosis factor alpha, interleukin 6 and sirtuin 1/AMP-activated protein kinase (AMPK)/nuclear factor kappa B (NF-κB) pathway and increasing the phosphorylation of glucose transporter 4, insulin receptor substrate 1, AKT and phosphoinositide 3-kinases, and attenuating blood sugar and regulation of insulin secretion, insulin resistance, and improvement of histopathological changes in pancreatic beta cells. Collectively, hawthorn can be considered as one new target for the research and development of innovative drugs for the prevention or treatment of DM and related problems.

Influence of layer separation on the determination of stomach smooth muscle properties

Uniaxial tensile experiments are a standard method to determine the contractile properties of smooth muscles. Smooth muscle strips from organs of the urogenital and gastrointestinal tract contain multiple muscle layers with different muscle fiber orientations, which are frequently not separated for the experiments. During strip activation, these muscle fibers contract in deviant orientations from the force-measuring axis, affecting the biomechanical characteristics of the tissue strips. This study aimed to investigate the influence of muscle layer separation on the determination of smooth muscle properties. Smooth muscle strips, consisting of longitudinal and circumferential muscle layers (whole-muscle strips [WMS]), and smooth muscle strips, consisting of only the circumferential muscle layer (separated layer strips [SLS]), have been prepared from the fundus of the porcine stomach. Strips were mounted with muscle fibers of the circumferential layer inline with the force-measuring axis of the uniaxial testing setup. The force-length (FLR) and force-velocity relationships (FVR) were determined through a series of isometric and isotonic contractions, respectively. Muscle layer separation revealed no changes in the FLR. However, the SLS exhibited a higher maximal shortening velocity and a lower curvature factor than WMS. During WMS activation, the transversally oriented muscle fibers of the longitudinal layer shortened, resulting in a narrowing of this layer. Expecting volume constancy of muscle tissue, this narrowing leads to a lengthening of the longitudinal layer, which counteracted the shortening of the circumferential layer during isotonic contractions. Consequently, the shortening velocities of the WMS were decreased significantly. This effect was stronger at high shortening velocities.

Gastric Electrical Pacing Reduces Apoptosis of Interstitial Cells of Cajal via Antioxidative Stress Effect Attributing to Phenotypic Polarization of M2 Macrophages in Diabetic Rats

BACKGROUND

Gastric electrical pacing (GEP) could restore interstitial cells of Cajal in diabetic rats. M2 macrophages contribute to the repair of interstitial cells of Cajal injury though secreting heme oxygenase-1 (HO-1). The aim of the study is to investigate the effects and mechanisms of gastric electrical pacing on M2 macrophages in diabetic models.

METHODS

Sixty male Sprague-Dawley rats were randomized into control, diabetic (DM), diabetic with the sham GEP (DM+SGEP), diabetic with GEP1 (5.5 cpm, 100 ms, 4 mA) (DM+GEP1), diabetic with GEP2 (5.5 cpm, 300 ms, 4 mA) (DM+GEP2), and diabetic with GEP3 (5.5 cpm, 550 ms, 4 mA) (DM+GEP3) groups. The apoptosis of interstitial cells of Cajal and the expression of macrophages were detected by immunofluorescence technique. The expression levels of the Nrf2/HO-1 and NF-κB pathway were evaluated using western blot analysis or immunohistochemical method. Malonaldehyde, superoxide dismutase, and reactive oxygen species were tested to reflect the level of oxidative stress.

RESULTS

Apoptosis of interstitial cells of Cajal was increased in the DM group but significantly decreased in the DM+GEP groups. The total number of macrophages was almost the same in each group. In the DM group, M1 macrophages were increased and M2 macrophages were decreased. However, M2 macrophages were dramatically increased and M1 macrophages were reduced in the DM+GEP groups. Gastric electrical pacing improved the Nrf2/HO-1 pathway and downregulated the phosphorylation of NF-κB. In the DM group, the levels of malonaldehyde and reactive oxygen species were elevated and superoxide dismutase was lowered, while gastric electrical pacing reduced the levels of malonaldehyde and reactive oxygen species and improved superoxide dismutase.

CONCLUSION

Gastric electrical pacing reduces apoptosis of interstitial cells of Cajal though promoting M2 macrophages polarization to play an antioxidative stress effect in diabetic rats, which associates with the activated Nrf2/HO-1 pathway and the phosphorylation of NF-κB pathway.

Electroceuticals in the Gastrointestinal Tract

The field of electroceuticals has attracted considerable attention over the past few decades as a novel therapeutic modality. The gastrointestinal (GI) tract (GIT) holds significant potential as a target for electroceuticals as the intersection of neural, endocrine, and immune systems. We review recent developments in electrical stimulation of various portions of the GIT (including esophagus, stomach, and small and large intestine) and nerves projecting to the GIT and supportive organs. This has been tested with varying degrees of success for several dysmotility, inflammatory, hormonal, and neurologic disorders. We outline a vision for the future of GI electroceuticals, building on advances in mechanistic understanding of GI physiology coupled with novel ingestible technologies. The next wave of electroceutical therapies will be minimally invasive and more targeted than current approaches, making them an indispensable tool in the clinical armamentarium.

Gastric Electrical Stimulation Has an Effect on Gastric Interstitial cells of Cajal (ICC) That is Associated With Mast Cells

Introduction

Gastric electrical stimulation (GES) is an emerging therapy for gastric motility disorders, showing improvement of gastroparesis related symptoms in previous studies. Interstitial cells of Cajal (ICC) and mast cells have been shown to have a relevant role in gastroparesis pathogenesis. However, the exact effects of GES in those cells is relatively unknown.

Methods

Full thickness biopsies (FTBx) of 20 patients with refractory gastroparesis were obtained at the time of GES placement and repeated when the device was exchanged (mean of 22.5 months between biopsies). A patient-reported outcomes survey was obtained during each office visit during this period. All biopsies were stained with cluster of differentiation 117 (CD117), S100, and mast cell tryptase antibodies and were analyzed.

Results

Half of the patients had a significant increase of ICC during the repeated biopsy compared with baseline (p=0.01) and the other half had significant decrease in ICC levels (p=0.006) but there was no noticeable difference in mast cells counts at baseline between groups. Mast cells analysis was performed in two different groups depending on ICC change from the baseline biopsy (CD117 increase vs CD117 decrease). There was only a significant increase of mast cells count within the CD117 worsened ICC group (p=0.007).

Conclusion

No significant increase in the number of mast cells count seen in patients who received a GES may indicate an improvement in overall inflammation in patients with refractory gastroparesis after GES placement.