Interstitial cells of Cajal and human colon motility in health and disease

Anorectal physiology and colonic motility in children with a history of tethered cord syndrome

OBJECTIVES

The understanding of the impact of tethered cord syndrome (TCS) on the physiology of the colorectal area is limited. Our aim was to describe anorectal and colonic motility in children with TCS and compare the findings to those of children with functional constipation (FC).

METHODS

We conducted a retrospective review of children with TCS who had an anorectal manometry (ARM) performed at our institution from January 2011 to September 2023. We recorded demographics, medical and surgical history, clinical symptoms, and treatment at time of ARM, ARM findings (resting pressure, push maneuver, rectal sensation, rectoanal inhibitory reflex [RAIR], and RAIR duration), and the final interpretation of colonic manometry (CM) if performed. We identified age and sex-matched control groups of children with FC.

RESULTS

We included 24 children with TCS (50% female) who had ARM testing (median age at ARM 6.0 years, interquartile range 4.0-11.8 years). All children had constipation at time of ARM. Nineteen children had detethering surgery before ARM was performed. No significant differences in ARM parameters were found between children who had detethering surgery before ARM and children with FC. Among the 24 children, 14 also had a CM performed (13/14 after detethering surgery). No significant differences in colonic motility were found between children with a history of TCS and children with FC.

CONCLUSIONS

Anorectal physiology and colonic motility are similar between children with a history of TCS and children with FC, suggesting that the underlying pathophysiology of defecatory disorders in children with and without history of TCS is similar.

Advances in the study of polysaccharides from Anemarrhena asphodeloides Bge.: A review

Anemarrhena asphodeloides Bge. (AA), a traditional Chinese medicine, is used clinically to treat inflammation, diabetes, osteoporosis, and tumors. Polysaccharides are the most abundant components in AA, and have antioxidant, immunomodulatory, anti-inflammatory, hypoglycemic, anti-osteoporosis, and laxative effects. It is necessary to conduct a comprehensive analysis on the structure and pharmacological activity of the polysaccharides from AA (PAAs). This review systematically summarizes the structural characteristics of PAAs, including the monosaccharide compositions, molecular weights, and backbone structures. We discuss the relationship between the structure and pharmacological activities of PAAs. The chemical modification methods of PAAs, including zinc chelation, carboxymethylation, and sulfation, are then reviewed. This review may offer new insights for research on the PAAs and polysaccharides with similar structures.

The human colon: Evidence for degenerative changes during aging and the physiological consequences

BACKGROUND

The incidence of constipation increases among the elderly (>65 years), while abdominal pain decreases. Causes include changes in lifestyle (e.g., diet and reduced exercise), disease and medications affecting gastrointestinal functions. Degenerative changes may also occur within the colo-rectum. However, most evidence is from rodents, animals with relatively high rates of metabolism and accelerated aging, with considerable variation in time course. In humans, cellular and non-cellular changes in the aging intestine are poorly investigated.

PURPOSE

To examine all available studies which reported the effects of aging on cellular and tissue functions of human isolated colon, noting the region studied, sex and age of tissue donors and study size. The focus on human colon reflects the ability to access full-thickness tissue over a wide age range, compared with other gastrointestinal regions. Details are important because of natural human variability. We found age-related changes within the muscle, in the enteric and nociceptor innervation, and in the submucosa. Some involve all regions of colon, but the ascending colon appears more vulnerable. Changes can be cell- and sublayer-dependent. Mechanisms are unclear but may include development of "senescent-like" and associated inflammaging, perhaps associated with increased mucosal permeability to harmful luminal contents. In summary, reduced nociceptor innervation can explain diminished abdominal pain among the elderly. Degenerative changes within the colon wall may have little impact on symptoms and colonic functions, because of high "functional reserve," but are likely to facilitate the development of constipation during age-related challenges (e.g., lifestyle, disease, and medications), now operating against a reduced functional reserve.

NF-κB pathway as a molecular target for curcumin in diabetes mellitus treatment: Focusing on oxidative stress and inflammation

Diabetes mellitus (DM) is a collection of metabolic disorder that is characterized by chronic hyperglycemia. Recent studies have demonstrated the crucial involvement of oxidative stress (OS) and inflammatory reactions in the development of DM. Curcumin (CUR), a natural compound derived from turmeric, exerts beneficial effects on diabetes mellitus through its interaction with the nuclear factor kappa B (NF-κB) pathway. Research indicates that CUR targets inflammatory mediators in diabetes, including tumor necrosis factor α (TNF-α) and interleukin-6 (IL-6), by modulating the NF-κB signaling pathway. By reducing the expression of these inflammatory factors, CUR demonstrates protective effects in DM by improving pancreatic β-cells function, normalizing inflammatory cytokines, reducing OS and enhancing insulin sensitivity. The findings reveal that CUR administration effectively lowered blood glucose elevation, reinstated diminished serum insulin levels, and enhanced body weight in Streptozotocin -induced diabetic rats. CUR exerts its beneficial effects in management of diabetic complications through regulation of signaling pathways, such as calcium-calmodulin (CaM)-dependent protein kinase II (CaMKII), peroxisome proliferator-activated receptor gamma (PPAR-γ), NF-κB, and transforming growth factor β1 (TGFB1). Moreover, CUR reversed the heightened expression of inflammatory cytokines (TNF-α, Interleukin-1 beta (IL-1β), IL-6) and chemokines like MCP-1 in diabetic specimens, vindicating its anti-inflammatory potency in counteracting hyperglycemia-induced alterations. CUR diminishes OS, avert structural kidney damage linked to diabetic nephropathy, and suppress NF-κB activity. Furthermore, CUR exhibited a protective effect against diabetic cardiomyopathy, lung injury, and diabetic gastroparesis. Conclusively, the study posits that CUR could potentially offer therapeutic benefits in relieving diabetic complications through its influence on the NF-κB pathway.

A bibliometric analysis of interstitial cells of Cajal research

Objective

The significance of interstitial cells of Cajal (ICC) in the gastrointestinal tract has garnered increasing attention. In recent years, approximately 80 articles on ICC have been published annually in various journals. However, no bibliometric study has specifically focused on the literature related to ICC. Therefore, we conducted a comprehensive bibliometric analysis of ICC to reveal dynamic scientific developments, assisting researchers in exploring hotspots and emerging trends while gaining a global perspective.

Methods

We conducted a literature search in the Web of Science Core Collection (WoSCC) from January 1, 2013, to December 31, 2023, to identify relevant literature on ICC. We employed bibliometric software, namely VOSviewer and CiteSpace, to analyze various aspects including annual publication output, collaborations, research hotspots, current status, and development trends in this domain.

Results

A total of 891 English papers were published in 359 journals by 928 institutions from 57 countries/regions. According to the keyword analysis of the literature, researchers mainly focused on "c-Kit," "expression," "smooth muscle," and "nitric oxide" related to ICC over the past 11 years. However, with "SIP syncytium," "ANO1," "enteric neurons," "gastrointestinal stromal tumors (GIST)," and "functional dyspepsia (FD)," there has been a growing interest in the relationship between ANO1, SIP syncytium, and ICC, as well as the role of ICC in the treatment of GIST and FD.

Conclusion

Bibliometric analysis has revealed the current status of ICC research. The association between ANO1, SIP syncytium, enteric neurons and ICC, as well as the role of ICC in the treatment of GIST versus FD has become the focus of current research. However, further research and collaboration on a global scale are still needed. Our analysis is particularly valuable to researchers in gastroenterology, oncology, and cell biology, providing insights that can guide future research directions.

Expression of Calretinin in the Cecal Muscularis Interna: Observation and Hypothetical Relevance to Appendicitis

BACKGROUND

The unexpected observation of calretinin immunoreactivity in smooth muscle cells in the muscularis propria of the cecum led to a more detailed examination of calretinin expression and its possible relationship to propulsive contractile activity around the vermiform appendix.

METHODS

Immunohistochemistry and RNA in situ hybridization were performed to analyze calretinin expression in intestinal samples from 33 patients at ages ranging from mid-gestation fetuses to adults, as well as in some potentially relevant animal models. Dual immunolabeling was done to compare calretinin localization with markers of smooth muscle and interstitial cells of Cajal.

RESULTS

Calretinin expression was observed consistently in the innermost smooth muscle layers of the muscularis interna in the human cecum, appendiceal base, and proximal ascending colon, but not elsewhere in the intestinal tract. Calretinin-positive smooth muscle cells did not co-express markers located in adjacent interstitial cells of Cajal. Muscular calretinin immunoreactivity was not detected in the ceca of mice or macaques, species which lack appendices, nor in the rabbit cecum or appendix.

CONCLUSIONS

Localized expression of calretinin in cecal smooth muscle cells may reduce the likelihood of retrograde, calcium-mediated propulsive contractions from the proximal colon and suppress pro-inflammatory fecal stasis in the appendix.

Ingesting yeast extract causes excitation of neurogenic and myogenic colonic motor patterns in the rat

Fermented foods play a significant role in the human diet for their natural, highly nutritious and healthy attributes. Our aim was to study the effect of yeast extract, a fermented substance extracted from natural yeast, on colonic motility to better understand its potential therapeutic role. A yeast extract was given to rats by gavage for 3 days, and myogenic and neurogenic components of colonic motility were studied using spatiotemporal maps made from video recordings of the whole colon ex vivo. A control group received saline gavages. The yeast extract caused excitation of the musculature by increasing the propagation length and duration of long-distance contractions, the major propulsive activity of the rat colon. The yeast extract also evoked rhythmic propulsive motor complexes (RPMCs) which were antegrade in the proximal and mid-colon and retrograde in the distal colon. RPMC activity was evoked by distention-induced neural activity, but it was myogenic in nature since we showed it to be generated by bethanechol in the presence of tetrodotoxin. In conclusion, ingestion of yeast extract stimulates rat colon motility by exciting neurogenic and myogenic control mechanisms.

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.

Network pharmacology combined with an animal model to reveal the material basis and mechanism of Amomum villosum in alleviating constipation in mice

Constipation is a prevalent gastrointestinal disorder, with its prevalence showing an annual upward trend. There are many factors involved in the occurrence of constipation, such as abnormal smooth muscle contraction and disorders of gastrointestinal hormone secretion. Amomum villosum (A. villosum) has been proven to be effective in improving digestive system diseases, but there is no report on improving constipation. Therefore, we used network pharmacology prediction combined with animal experiments to explore the key active components of A. villosum and their pharmacological mechanisms. The results of network pharmacological prediction showed that β-sitosterol was the key laxative compound of A. villosum, which may play a laxative role by activating the adrenoceptor alpha 1 A-myosin light chain (ADRA1A-MLC) pathway. Further animal experiments showed that β-sitosterol could significantly shorten the time to first black stool; increase faecal weight, faecal number, and faecal water content; and promote gastrointestinal motility. β-sitosterol may promote intestinal motility by upregulating the expression of ADRA1A and myosin light chain 9 (Myl9) mRNA and protein in the colon, thereby activating the ADRA1A-MLC signalling pathway. In addition, it is possible to improve constipation symptoms by regulating serum neurotransmitters and gastrointestinal motility-related factors, such as the serum content of 5-hydroxytryptamine (5-HT) and acetylcholinesterase (AchE) and the mRNA expression of 5-hydroxytryptamine receptor 4 (5-HT4), stem cell factor (SCF), stem cell factor receptor (c-Kit) and smooth muscle myosin light chain kinase (smMLCK) in the colon. These results lay a foundation for the application of A. villosum and β-sitosterol in constipation.

Validation of body surface colonic mapping (BSCM) against high resolution colonic manometry for evaluation of colonic motility

Abnormal cyclic motor pattern (CMP) activity is implicated in colonic dysfunction, but the only tool to evaluate CMP activity, high-resolution colonic manometry (HRCM), remains expensive and not widely accessible. This study aimed to validate body surface colonic mapping (BSCM) through direct correlation with HRCM. Synchronous meal-test recordings were performed in asymptomatic participants with intact colons. A signal processing method for BSCM was developed to detect CMPs. Quantitative temporal analysis was performed comparing the meal responses and motility indices (MI). Spatial heat maps were also compared. Post-study questionnaires evaluated participants' preference and comfort/distress experienced from either test. 11 participants were recruited and 7 had successful synchronous recordings (5 females/2 males; median age: 50 years [range 38-63]). The best-correlating MI temporal analyses achieved a high degree of agreement (median Pearson correlation coefficient (Rp) value: 0.69; range 0.47-0.77). HRCM and BSCM meal response start and end times (Rp = 0.998 and 0.83; both p < 0.05) and durations (Rp = 0.85; p = 0.03) were similar. Heat maps demonstrated good spatial agreement. BSCM is the first non-invasive method to be validated by demonstrating a direct spatio-temporal correlation to manometry in evaluating colonic motility.

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.

Effect of acupuncture therapy for postoperative gastrointestinal dysfunction in gastric and colorectal cancers: an umbrella review

Background

Gastrointestinal dysfunction is a prevalent postoperative complication in patients undergoing surgery for gastric cancer and colorectal cancer. Acupuncture holds promise as a great potential therapeutic intervention. The efficacy of acupuncture therapy for postoperative gastrointestinal dysfunction has been assessed in some studies, however, the variability in results and study quality influences practical clinical application. Therefore, it is necessary to summarize and analyze the published clinical research data in this field.

Objective

This study aimed to synthesize evidence from systematic reviews and meta-analyses in order to assess the efficacy of acupuncture therapy for postoperative gastrointestinal dysfunction in patients with gastric and colorectal cancer.

Design

Umbrella review of systematic reviews and meta-analyses.

Methods

We searched China National Knowledge Infrastructure (CNKI), Wanfang Data Knowledge Service Platform (Wanfang), China Science and Technology Journal Database (VIP), Chinese biomedical literature service system (SinoMed), PubMed, Embase, Cochrane Library, and Web of Science for all systematic review/meta-analysis of acupuncture for postoperative gastrointestinal dysfunction in gastric and colorectal cancers. From the establishment of the database to July 8, 2023. Two independent reviewers conducted literature extraction and evaluation. The quality of included studies was assessed using The preferred reporting items for systematic reviews and meta-analysis statements 2020 (PRISMA2020), the quality of the methods was assessed using a measuring tool to assess systematic reviews 2 (AMSTAR 2), and the level of evidence was assessed using the grading of recommendations assessment, development, and evaluation (GRADE). The statistical analysis was conducted using RevMan 5.4, and the effect size was expressed as Odds Ratio (OR), Mean Difference (MD), and 95% confidence interval (CI) based on the extracted data type (test level α= 0.05). The heterogeneity was assessed using the I 2 statistic and Q-test (χ2). The outcome indicators such as time to first defecation and time to first flatus were utilized as endpoints to assess the efficacy of different acupuncture therapies.

Results

A total of six systematic reviews/meta-analyses were included in this study, involving 12 different acupuncture therapies. PRISMA 2020 indicated that the studies all scored between 13-20.5. There were deficiencies in protocol and registration, assessment of the quality of evidence for outcome indicators, risk of bias, and declaration of conflict of interest. The AMSTAR 2 evaluations showed that five studies were very low quality and one was low quality. The level of evidence for various acupuncture interventions varied from very low to moderate.For patients with gastrointestinal dysfunction after gastric cancer surgery, ear acupressure [MD=-11.92, 95% (-14.39,-9.44), P<0.00001], moxibustion [MD=-19.16, 95% (-23.00,-16.22), P<0.00001], warm needling [MD=-12.81, 95% (-17.61,-8.01), P<0.00001], acupoint application [MD=-6.40, 95% (-10.26,-2.54), P=0.001], manual acupuncture [MD=-18.32, 95% (-26.31,-10.39), P<0.00001] and transcutaneous electrical acupoint stimulation (TEAS) [MD=-5.17, 95% (-9.59,-0.74), P=0.02] could promote the recovery of gastrointestinal function after surgery.For postoperative colorectal cancer patients, electroacupuncture [MD=-15.17, 95% (-28.81,-1.54), P<0.05], manual acupuncture [MD=-20.51, 95% (-39.19,-1.84), P<0.05], warm needling [MD=-18.55, 95% (-23.86,-13.24), P<0.05], ear acupressure [MD=-5.38, 95% (-9.80,-0.97), P<0.05], acupoint application [MD=-26.30, 95% (-32.81,-19.79), P<0.05], ear acupressure+acupressure [MD=-9.67, 95% (-13.58,-5.76), P<0.05], ear acupressure+manual acupuncture [MD=-18.70, 95% (-21.01,-16.39), P<0.05], ear acupressure+moxibustion [MD=-22.90, 95% (-30.10,-15.70), P<0.05], moxibustion+acupressure [MD=-14.77, 95% (-20.59,-8.95), P<0.05] improved postoperative gastrointestinal function. In addition, the efficacy of acupressure [MD=-12.00, 95% (-31.60,7.60), P>0.05] needed to be further demonstrated.

Conclusion

Acupuncture therapy has a positive therapeutic impact on postoperative gastrointestinal dysfunction in gastric and colorectal cancers, but this finding should still be taken with caution.

Idiopathic Slow Transit Constipation: Pathophysiology, Diagnosis, and Management

Slow transit constipation (STC) has an estimated prevalence of 2-4% of the general population, and although it is the least prevalent of the chronic constipation phenotypes, it more commonly causes refractory symptoms and is associated with significant psychosocial stress, poor quality of life, and high healthcare costs. This review provides an overview of the pathophysiology, diagnosis, and management options in STC. STC occurs due to colonic dysmotility and is thought to be a neuromuscular disorder of the colon. Several pathophysiologic features have been observed in STC, including reduced contractions on manometry, delayed emptying on transit studies, reduced numbers of interstitial cells of Cajal on histology, and reduced amounts of excitatory neurotransmitters within myenteric plexuses. The underlying aetiology is uncertain, but autoimmune and hormonal mechanisms have been hypothesised. Diagnosing STC may be challenging, and there is substantial overlap with the other clinical constipation phenotypes. Prior to making a diagnosis of STC, other primary constipation phenotypes and secondary causes of constipation need to be ruled out. An assessment of colonic transit time is required for the diagnosis and can be performed by a number of different methods. There are several different management options for constipation, including lifestyle, dietary, pharmacologic, interventional, and surgical. The effectiveness of the available therapies in STC differs from that of the other constipation phenotypes, and prokinetics often make up the mainstay for those who fail standard laxatives. There are few available management options for patients with medically refractory STC, but patients may respond well to surgical intervention. STC is a common condition associated with a significant burden of disease. It can present a clinical challenge, but a structured approach to the diagnosis and management can be of great value to the clinician. There are many therapeutic options available, with some having more benefits than others.

Plasticity of colonic enteric nervous system following spinal cord injury in male and female rats

BACKGROUND

Neurogenic bowel is a dysmotility disorder following spinal cord injury (SCI) that negatively impacts quality of life, social integration, and physical health. Colonic transit is directly modulated by the enteric nervous system. Interstitial Cells of Cajal (ICC) distributed throughout the small intestine and colon serve as specialized pacemaker cells, generating rhythmic electrical slow waves within intestinal smooth muscle, or serve as an interface between smooth muscle cells and enteric motor neurons of the myenteric plexus. Interstitial Cells of Cajal loss has been reported for other preclinical models of dysmotility, and our previous experimental SCI study provided evidence of reduced excitatory and inhibitory enteric neuronal count and smooth muscle neural control.

METHODS

Immunohistochemistry for the ICC-specific marker c-Kit was utilized to examine neuromuscular remodeling of the distal colon in male and female rats with experimental SCI.

KEY RESULTS

Myenteric plexus ICC (ICC-MP) exhibited increased cell counts 3 days following SCI in male rats, but did not significantly increase in females until 3 weeks after SCI. On average, ICC-MP total primary arborization length increased significantly in male rats at 3-day, 3-week, and 6-week time points, whereas in females, this increase occurred most frequently at 6 weeks post-SCI. Conversely, circular muscle ICC (ICC-CM) did not demonstrate post-SCI changes.

CONCLUSIONS AND INFERENCES

These data demonstrate resiliency of the ICC-MP in neurogenic bowel following SCI, unlike seen in other related disease states. This plasticity underscores the need to further understand neuromuscular changes driving colonic dysmotility after SCI in order to advance therapeutic targets for neurogenic bowel treatment.

Understanding the potential causes of gastrointestinal dysfunctions in multiple system atrophy

Multiple system atrophy (MSA) is a rare, progressive neurodegenerative disorder characterised by autonomic, pyramidal, parkinsonian and/or cerebellar dysfunction. Autonomic symptoms of MSA include deficits associated with the gastrointestinal (GI) system, such as difficulty swallowing, abdominal pain and bloating, nausea, delayed gastric emptying, and constipation. To date, studies assessing GI dysfunctions in MSA have primarily focused on alterations of the gut microbiome, however growing evidence indicates other structural components of the GI tract, such as the enteric nervous system, the intestinal barrier, GI hormones, and the GI-driven immune response may contribute to MSA-related GI symptoms. Here, we provide an in-depth exploration of the physiological, structural, and immunological changes theorised to underpin GI dysfunction in MSA patients and highlight areas for future research in order to identify more suitable pharmaceutical treatments for GI symptoms in patients with MSA.

Haustral rhythmic motor patterns of the human large bowel revealed by ultrasound

Effective and widely available strategies are needed to diagnose colonic motility dysfunction. We investigated whether ultrasonography could generate spatiotemporal maps combined with motor pattern frequency analysis, to become a noninvasive method to characterize human colon motor patterns. Abdominal colonic ultrasonography was performed on healthy subjects (N = 7), focusing on the detailed recording of spontaneous haustral activities. We developed image segmentation and frequency analysis software to analyze the motor patterns captured. Ultrasonography recordings of the ascending, transverse, and descending colon identified three distinct rhythmic motor patterns: the 1 cycle/min and the 3 cycles/min cyclic motor pattern were seen throughout the whole colon, whereas the 12 cycles/min cyclic motor pattern was identified in the ascending colon. The rhythmic motor patterns of the human colon that are associated with interstitial cells of Cajal-associated pacemaking activity can be accurately identified and quantified using ultrasound.NEW & NOTEWORTHY Ultrasonography in the clinical field is an underutilized tool for assessing colonic motility; however, with the addition of frequency analysis techniques, it provides a method to identify human colonic motor patterns. Here we report on the 1, 3, and 12 cpm rhythmic motor patterns. Ultrasound has the potential to become a bedside assessment for colonic dysmotility and may reveal the health of interstitial cells of Cajal (ICC) pacemaker activities.

The Crucial Role of the Interstitial Cells of Cajal in Neurointestinal Diseases

Neurointestinal diseases result from dysregulated interactions between the nervous system and the gastrointestinal (GI) tract, leading to conditions such as Hirschsprung's disease and irritable bowel syndrome. These disorders affect many people, significantly diminishing their quality of life and overall health. Central to GI motility are the interstitial cells of Cajal (ICC), which play a key role in muscle contractions and neuromuscular transmission. This review highlights the role of ICC in neurointestinal diseases, revealing their association with various GI ailments. Understanding the functions of the ICC could lead to innovative perspectives on the modulation of GI motility and introduce new therapeutic paradigms. These insights have the potential to enhance efforts to combat neurointestinal diseases and may lead to interventions that could alleviate or even reverse these conditions.

Body Surface Gastrointestinal Potential Mapping: A Simulation Framework to Evaluate Source Separation Algorithms. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2023;2023:1-4. [PMID: 38083102 DOI: 10.1109/embc40787.2023.10340911] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

Gastrointestinal (GI) potential mapping could be useful for evaluating GI motility disorders. Such disorders are found in inflammatory bowel diseases, such as Crohn's disease, or GI functional disorders. GI potential mapping data originate from a mixture of several GI electrophysiological sources (termed ExG) and other noise sources, including the electrocardiogram (ECG) and respiration. Denoising and/or source separation techniques are required, however, with real measurements, no ground truth is available. In this paper we propose a framework for the simulation of body surface GI potential mapping data. The framework is an electrostatic model, based on fecgsyn toolbox, using dipoles as electrical sources for the heart, stomach, small bowel and colon, and an array of surface electrodes. It is shown to generate realistic ExG waveforms, which are then used to compare several ECG and respiration cancellation techniques, based on, fast independent component analysis (FastICA) and pseudo-periodic component analysis (PiCA). The best performance was obtained with PiCA with a median root mean squared error of 0.005.

Arctiin alleviates functional constipation by enhancing intestinal motility in mice

Functional constipation (FC), a common symptom that is primarily associated with intestinal motility dysfunction, is a common problem worldwide. Arctiin (Arc) is a lignan glycoside isolated from the Chinese herbal medicine Arctium lappa L., which is a health food in China. The present study aimed to evaluate the laxative effects of Arc against FC in mice. A model of FC induced by loperamide (5 mg/kg) was established in male Institute of Cancer Research (ICR) mice. Arc was administered at a dose of 100 mg/kg as a protective agent. The faecal status, intestinal motility and histological analyses were evaluated. Furthermore, the levels of gastrointestinal motility-associated neurotransmitters, such as motilin (MTL), nitric oxide (NO), and brain-derived neurotrophic factor (BDNF) and the protective effect of Arc on interstitial cells of Cajal (ICC) were assessed. Arc treatment reversed the loperamide-induced reduction in faecal number and water content and the intestinal transit ratio in ICR mice. Histological analysis confirmed that Arc administration mitigated colonic injury. Moreover, Arc treatment increased levels of motilin and brain-derived neurotrophic factor while decreasing nitric oxide levels and ICC injury in the colon of FC mice. Arc decreased inflammation induction and aquaporin expression levels. Owing to its pro-intestinal motility property, Arc was shown to have a protective effect against FC and may thus serve as a promising therapeutic strategy for the management of FC.

Interstitial cells of Cajal: clinical relevance in pediatric gastrointestinal motility disorders

Interstitial cells of Cajal (ICCs) are pacemaker cells of gastrointestinal motility that generate and transmit electrical slow waves to smooth muscle cells in the gut wall, thus inducing phasic contractions and coordinated peristalsis. Traditionally, tyrosine-protein kinase Kit (c-kit), also known as CD117 or mast/stem cell growth factor receptor, has been used as the primary marker of ICCs in pathology specimens. More recently, the Ca2+-activated chloride channel, anoctamin-1, has been introduced as a more specific marker of ICCs. Over the years, various gastrointestinal motility disorders have been described in infants and young children in which symptoms of functional bowel obstruction arise from ICC-related neuromuscular dysfunction of the colon and rectum. The current article provides a comprehensive overview of the embryonic origin, distribution, and functions of ICCs, while also illustrating the absence or deficiency of ICCs in pediatric patients with Hirschsprung disease intestinal neuronal dysplasia, isolated hypoganglionosis, internal anal sphincter achalasia, and congenital smooth muscle cell disorders such as megacystis microcolon intestinal hypoperistalsis syndrome.

The enteric nervous system

Of all the organ systems in the body, the gastrointestinal tract is the most complicated in terms of the numbers of structures involved, each with different functions, and the numbers and types of signaling molecules utilized. The digestion of food and absorption of nutrients, electrolytes, and water occurs in a hostile luminal environment that contains a large and diverse microbiota. At the core of regulatory control of the digestive and defensive functions of the gastrointestinal tract is the enteric nervous system (ENS), a complex system of neurons and glia in the gut wall. In this review, we discuss 1) the intrinsic neural control of gut functions involved in digestion and 2) how the ENS interacts with the immune system, gut microbiota, and epithelium to maintain mucosal defense and barrier function. We highlight developments that have revolutionized our understanding of the physiology and pathophysiology of enteric neural control. These include a new understanding of the molecular architecture of the ENS, the organization and function of enteric motor circuits, and the roles of enteric glia. We explore the transduction of luminal stimuli by enteroendocrine cells, the regulation of intestinal barrier function by enteric neurons and glia, local immune control by the ENS, and the role of the gut microbiota in regulating the structure and function of the ENS. Multifunctional enteric neurons work together with enteric glial cells, macrophages, interstitial cells, and enteroendocrine cells integrating an array of signals to initiate outputs that are precisely regulated in space and time to control digestion and intestinal homeostasis.

Revised spectral metrics for body surface measurements of gastric electrophysiology

BACKGROUND

Electrogastrography (EGG) non-invasively evaluates gastric function but has not achieved common clinical adoption due to several technical limitations. Body Surface Gastric Mapping (BSGM) has been introduced to overcome these limitations, but pitfalls in traditional metrics used to analyze spectral data remain unaddressed. This study critically evaluates five traditional EGG metrics and introduces improved BSGM spectral metrics, with validation in a large cohort.

METHODS

Pitfalls in five EGG metrics were assessed (dominant frequency, percentage time normogastria, amplitude, power ratio, and instability coefficient), leading to four revised BSGM spectral metrics. Traditional and revised metrics were compared to validate performance using a standardized 100-subject database of BSGM tests (30 min baseline; 4-h postprandial) recorded using Gastric Alimetry® (Alimetry).

KEY RESULTS

BMI and amplitude were highly correlated (r = -0.57, p < 0.001). We applied a conservative BMI correction to obtain a BMI-adjusted amplitude metric (r = -0.21, p = 0.037). Instability coefficient was highly correlated with both dominant frequency (r = -0.44, p < 0.001), and percent bradygastria (r = 0.85, p < 0.001), in part due to misclassification of low frequency transients as gastric activity. This was corrected by introducing distinct gastric frequency and stability metrics (Principal Gastric Frequency and Gastric Alimetry Rhythm Index (GA-RI)^TM ) that were uncorrelated (r = 0.14, p = 0.314). Only 28% of subjects showed a maximal averaged amplitude within the first postprandial hour. Calculating Fed:Fasted Amplitude Ratio over a 4-h postprandial window yielded a median increase of 0.31 (IQR 0-0.64) above the traditional ratio.

CONCLUSIONS & INFERENCES

The revised metrics resolve critical pitfalls impairing the performance of traditional EGG, and should be applied in future BSGM spectral analyses.

Luteolin ameliorates loperamide-induced functional constipation in mice

Functional constipation (FC) is one of the most common gastrointestinal disorders characterized by hard stools and infrequent bowel movements, which is associated with dysfunction of the enteric nervous system and intestinal motility. Luteolin, a naturally occurring flavone, was reported to possess potential pharmacological activities on intestinal inflammation and nerve injury. This study aimed to explore the role of luteolin and its functional mechanism in loperamide-induced FC mice. Our results showed that luteolin treatment reversed the reduction in defecation frequency, fecal water content, and intestinal transit ratio, and the elevation in transit time of FC models. Consistently, luteolin increased the thickness of the muscular layer and lessened colonic histopathological injury induced by loperamide. Furthermore, we revealed that luteolin treatment increased the expression of neuronal protein HuC/D and the levels of intestinal motility-related biomarkers, including substance P (SP), vasoactive intestinal polypeptide (VIP), and acetylcholine (ACh), as well as interstitial cells of Cajal (ICC) biomarker KIT proto-oncogene, receptor tyrosine kinase (C-Kit), and anoctamin-1 (ANO1), implying that luteolin mediated enhancement of colonic function and contributed to the anti-intestinal dysmotility against loperamide-induced FC. Additionally, luteolin decreased the upregulation of aquaporin (AQP)-3, AQP-4, and AQP-8 in the colon of FC mice. In summary, our data showed that luteolin might be an attractive option for developing FC-relieving medications.

Myths and misconceptions about childhood constipation

Many widely held beliefs and assumptions concerning childhood constipation continue to interfere with rational management of childhood constipation. Although many still believe that constipation is not a common disease, about 9.5% of the world's children suffer from chronic constipation. Most of these children live in non-Western countries. There are major misconceptions about the etiology of constipation as a significant proportion of clinicians still believe that constipation is caused by some form an organic pathology, whereas in reality, the majority have functional constipation. Contrary to a commonly held belief that children outgrow constipation without long-term problems, there is evidence that constipation leads to significant bowel and psychological consequences and has a major impact on the quality of life which detrimentally affects future health and education. Finally, ineffective management strategies such as increasing fiber and water in the diet, and short duration of treatment owing to the fear that long-term laxative treatment leads to colonic dysfunction, interfere with effective therapeutic strategies.   Conclusions: It is apparent that myths and misconception often lead to wrong assumptions regarding the distribution of the disease, its etiology, pathophysiology, and management leading to ordering incorrect investigations and ineffective therapeutic strategies while spending large sums of public funds unnecessarily. Poorly treated constipation leads to deleterious psychological consequences predisposing children to develop significant psychological damage and bowel dysfunctions. This review aims to challenge these myths about various elements of constipation by exploring the existing literature and encouraging clinicians to have a fresh look at old concepts that could interfere with the well-being of children with constipation. What is Known: • Childhood constipation is a growing problem in the world leading to significant suffering and high healthcare expenditure • Myths and misconceptions lead to poor management strategies causing psychological and bowel damage What is New: • Organic, systemic, and bowel disorders leading to constipation are uncommon, and in the majority, it arises due to deliberate fecal withholding and most investigations ordered by clinicians are not very helpful in the management • Most non-pharmacological interventions are not effective in the day-to-day management of childhood constipation. The use of laxatives is considered to be the first-line management strategy.

Faecal incontinence is associated with an impaired rectosigmoid brake and improved by sacral neuromodulation

BACKGROUND

The rectosigmoid brake, characterised by retrograde cyclic motor patterns on high-resolution colonic manometry, has been postulated as a contributor to the maintenance of bowel continence. Sacral neuromodulation (SNM) is an effective therapy for faecal incontinence, but its mechanism of action is unclear. This study aims to investigate the colonic motility patterns in the distal colon of patients with faecal incontinence, and how these are modulated by SNM.

METHODS

A high-resolution fibreoptic colonic manometry catheter, containing 36 sensors spaced at 1-cm intervals, was positioned in patients with faecal incontinence undergoing stage 1 SNM. One hour of pre- and post meal recordings were obtained followed by pre- and post meal recordings with suprasensory SNM. A 700-kcal meal was given. Data were analysed to identify propagating contractions.

RESULTS

Fifteen patients with faecal incontinence were analysed. Patients had an abnormal meal response (fewer retrograde propagating contractions compared to controls; p = 0.027) and failed to show a post meal increase in propagating contractions (mean 17 ± 6/h premeal vs. 22 ± 9/h post meal, p = 0.438). Compared to baseline, SNM significantly increased the number of retrograde propagating contractions in the distal colon (8 ± 3/h premeal vs. 14 ± 3/h premeal with SNM, p = 0.028). Consuming a meal did not further increase the number of propagating contractions beyond the baseline upregulating effect of SNM.

CONCLUSION

The rectosigmoid brake was suppressed in this cohort of patients with faecal incontinence. SNM may exert a therapeutic effect by modulating this rectosigmoid brake.

Immune niches orchestrated by intestinal mesenchymal stromal cells lining the crypt-villus

The mammalian intestine is an organ that can be spatially defined by two axes: longitudinal and vertical. Such anatomical structure ensures the maintenance of a relatively immuno-quiescent and proliferation-promoting crypt for intestinal stem cell differentiation while actively warding off the invading intestinal microbes at the villus tip during digestion and nutrient absorption. Such behavior is achieved by the fine coordination among intestinal epithelial cells, intestinal mesenchymal stromal cells and tissue-resident immune cells like myeloid cells and lymphocytes. Among these cell types resided in the colon, intestinal mesenchymal stromal cells are considered to be the essential link between epithelium, vasculature, neuronal system, and hematopoietic compartment. Recent advancement of single cell and spatial transcriptomics has enabled us to characterize the spatial and functional heterogeneity of intestinal mesenchymal stromal cells. These studies reveal distinctive intestinal mesenchymal stromal cells localized in different regions of the intestine with diverse functions including but not limited to providing cytokines and growth factors essential for different immune cells and epithelial cells which predict niche formation for immune function from the villus tip to the crypt bottom. In this review, we aim to provide an overall view of the heterogeneity of intestinal mesenchymal stromal cells, the spatial distribution of these cells along with their interaction with immune cells and the potential regulatory cytokine profile of these cell types. Summarization of such information may enrich our current understanding of the immuno-regulatory functions of the newly identified mesenchymal stromal cell subsets beyond their epithelial regulatory function.

Investigation of the improving effect of raw and charred hawthorn on functional dyspepsia based on interstitial cells of Cajal

Background

Raw hawthorn (RH) is a traditional Chinese medicine commonly used to treat indigestion. Charred hawthorn (CH) is obtained from RH by charring. It is reported that the effect of CH treatment on dyspepsia is stronger than RH. However, this has not been fully proven. The purpose of this study was to compare the effects of RH and CH on functional dyspepsia (FD) model rats. And contribute to the development of dietary therapy for dyspepsia.

Methods

SPF-grade male SD rats were divided into 5 groups: the control group, the model group, the Mos group, the RH group, and the CH group. The FD rat model was established by using the methods of water restriction, fasting, tilting cage restraint, day and night upside down, swimming, and tail damping. The body weight of rats in each group was recorded. And the gastric emptying rate, intestinal propulsive rate, and the levels of motilin (MTL), gastrin (GAS), and 5-HT in serum were compared in each group. The expression of C-kit in the stomach and small intestine of each group was compared by immunofluorescence and PCR.

Results

RH and CH could increase weight, improve the gastric emptying rate and intestinal propulsive rate, and promote the secretion of motilin (MTL), gastrin (GAS), and 5-HT in the serum of FD rats. RH and CH can upregulate the expression of the characteristic protein c-kit of ICC in the stomach and small intestine of FD model rats, and the effect of CH is stronger than RH.

Conclusion

RH and CH may increase the number of interstitial cells of Cajal (ICC) in the gastrointestinal tract by upregulating c-kit expression, thus improving gastrointestinal motility in FD model rats. And compared with RH, CH has certain advantages.

The role of colonic motility in low anterior resection syndrome

Low anterior resection syndrome (LARS) describes the symptoms and experiences of bowel dysfunction experienced by patients after rectal cancer surgery. LARS is a complex and multifactorial syndrome exacerbated by factors such as low anastomotic height, defunctioning of the colon and neorectum, and radiotherapy. There has recently been growing awareness and understanding regarding the role of colonic motility as a contributing mechanism for LARS. It is well established that rectosigmoid motility serves an important role in coordinating rectal filling and maintaining continence. Resection of the rectosigmoid may therefore contribute to LARS through altered distal colonic and neorectal motility. This review evaluates the role of colonic motility within the broader pathophysiology of LARS and outlines future directions of research needed to enable targeted therapy for specific LARS phenotypes.

Electroacupuncture Improves Intestinal Motility through Exosomal miR-34c-5p Targeting SCF/c-Kit Signaling Pathway in Slow Transit Constipation Model Rats

Background. The pathogenesis of slow transit constipation (STC) is associated with exosomal miR-34c-5p. Electroacupuncture (EA) improves gastrointestinal motility in gastrointestinal disorders, especially STC. Our study aimed to explore the mechanism by which EA improves intestinal motility by modulating the release of exosomes and the transmission of exosomal miR-34c-5p. Methods. Fifty rats were randomly divided into five groups. STC model rats were induced, and GW4869, the exosome release inhibitor, was used to inhibit the release of exosome. The serum exosomes were authenticated under a transmission electron microscope and nanoparticle tracking analysis. RT-qPCR detected the expression of miR-34c-5p in serum exosomes and colonic tissues. The fecal number in 24 hours, Bristol scores, and intestinal transit rates were used to assess intestinal motility. Subsequently, hematoxylin and eosin (H&E) staining was used to examine the colonic mucosal histology. Finally, the expression of stem cell factor (SCF) and receptor tyrosine kinase (c-Kit) protein was measured using immunohistochemistry staining. Results. We found that EA upregulated exosomal miR-34c-5p in serum and downregulated miR-34c-5p in colonic tissues ( $P<0.01$ ). EA improved fecal numbers in 24 hours, Bristol scores, and intestinal transit rates in STC rats ( $P<0.01$ ). EA recovered the colonic histological structure and enhanced the expression of SCF and c-Kit protein ( $P<0.01$ ). The therapeutic effect of EA was attenuated after inhibiting the release of the exosome. Conclusion. Our results indicated that EA improves intestinal motility in STC rats by transporting of exosomal miR-34c-5p targeting the SCF/c-Kit signaling pathway.

Diagnosis of colonic dysmotility associated with autonomic dysfunction in patients with chronic refractory constipation

We report the first study assessing human colon manometric features and their correlations with changes in autonomic functioning in patients with refractory chronic constipation prior to consideration of surgical intervention. High-resolution colonic manometry (HRCM) with simultaneous heart rate variability (HRV) was performed in 14 patients, and the resulting features were compared to healthy subjects. Patients were categorized into three groups that had normal, weak, or no high amplitude propagating pressure waves (HAPWs) to any intervention. We found mild vagal pathway impairment presented as lower HAPW amplitude in the proximal colon in response to proximal colon balloon distention. Left colon dysmotility was observed in 71% of patients, with features of (1) less left colon HAPWs, (2) lower left colon HAPW amplitudes (69.8 vs 102.3 mmHg), (3) impaired coloanal coordination, (4) left colon hypertonicity in patients with coccyx injury. Patients showed the following autonomic dysfunction: (1) high sympathetic tone at baseline, (2) high sympathetic reactivity to active standing and meal, (3) correlation of low parasympathetic reactivity to the meal with absence of the coloanal reflex, (4) lower parasympathetic and higher sympathetic activity during occurrence of HAPWs. In conclusion, left colon dysmotility and high sympathetic tone and reactivity, more so than vagal pathway impairment, play important roles in refractory chronic constipation and suggests sacral neuromodulation as a possible treatment.

Distribution of interstitial cells of Cajal in the Esophagus and change in distribution after thoracic trauma

Interstitial cells of Cajal (ICCs) function as pacemaker cells in the gastrointestinal tract. Acute thoracic trauma is a common and lethal cause of death due to physical trauma caused by traffic accidents. This study aimed to explore the distribution of esophageal ICCs and distribution changes observed after acute thoracic trauma. Thirty rabbits were randomly divided into a control group and two study groups. The control group animals underwent an esophagectomy. All animals in the study groups underwent right chest puncture using the Hopkinson bar technique. The study groups were subjected to esophagectomy 24 and 72 h after chest puncture. Distribution, morphology, and density of esophageal ICCs were detected using transmission electron microscopy, toluidine blue staining, and immunohistochemistry. Apoptosis of esophageal ICCs was evaluated using the terminal deoxynucleotidyl transferase (TdT) dUTP Nick-End Labeling assay. Western blotting and reverse transcription polymerase chain reaction were used to detect changes in the SCF/c-kit signaling pathway. Esophageal ICCs distribution and SCF/c-kit signal pathway decreased from the upper part to the lower part in both physiological state and after thoracic trauma. In contrast, death of ICCs increased from the upper part to the lower part, both in physiological and injured state (P < 0.05). After thoracic trauma, increased ICCs and decreased death of ICCs in all parts of the esophagus (P < 0.05) were observed. The observed distribution and changes in esophageal ICCs would have an impact on motility and motility disorders of the esophagus.

Long non-coding RNA MEG3 promotes tumor necrosis factor-alpha induced oxidative stress and apoptosis in interstitial cells of cajal via targeting the microRNA-21 /I-kappa-B-kinase beta axis

Interstitial Cells of Cajal (ICC) plays a critical role in the peristaltic contractions of the gastrointestinal and urinary tract. The dysfunction and loss of ICC contributes to hypokinetic disease, such as gallstoneand ureteropelvic junction obstruction . In the present study, we identified the underlying driving molecular signals of oxidative stress and apoptosis in ICC. ICC was isolated from small intestine of Balb/c mice, and stimulated with tumor necrosis factor-alpha (TNF-α). MTT and flow cytometry were performed to assess cell viability, apoptosis, and the level of reactive oxygen species in ICC, respectively. The level of malondialdehyde, superoxide dismutase, and glutathione peroxidase in cells were measured to assess oxidative stress. The expression of inflammatory factors (interleukin, IL-1 and IL-6) and apoptosis-related proteins were detected by western blot. We observed that TNF-αinduced inflammation, oxidative stress and cell apoptosis in ICC. By using quantitative real-time PCR , we verified that the expression of long non-coding RNAMEG3 was elevated by TNF-α in ICC. Silencing MEG3 reversed inflammation, oxidative stress, and cell apoptosisin TNF-α-treated ICC. Subsequently, we confirmed that MEG3 sponged cytoprotective miR-21 to upregulate the expression of I-kappa-B-kinase beta (IKKB) and activate the nuclear factor kappa-B (NF-κB) pathway. Both miR-21 overexpression and IKKB knockdown reduced TNF-α-induced above symptoms in ICC. Taken together, we can conclude that MEG3 mediates inflammation, oxidative stress and apoptosis in TNF-α-treated ICC via the miR-21/IKKB-NF-κB axis. The study improves our understanding of the molecular mechanism of ICC reduction related diseases.