Gastrointestinal neuromuscular pathology in chronic constipation

Analysis of differentially expressed lncRNAs and mRNAs associated with slow‑transit constipation

Slow transit constipation (STC) is a refractory gastrointestinal disease, accounting for approximately 13 ∼ 37 % of chronic constipation. However, the molecular mechanism of STC remains poorly understood. Herein, this study aims to identify the key mRNAs and lncRNAs associated with STC. To this end, we performed high-throughput RNA sequencing to identify differentially expressed (DE) mRNAs and lncRNAs in the whole-layer sigmoid intestinal tissues from 4 STC patients and 4 non-STC patients. The identified DE lncRNAs and mRNAs were validated through quantitative real-time PCR. Weighted gene co-expression network analysis (WGCNA) and Pearson correlation analysis were conducted to determine the significantly correlated DE mRNA-lncRNA pairs. A total of 1420 DE lncRNAs and 1634 DE mRNAs were identified. Kyoto Encyclopedia of Genes and Genomes analysis of DE mRNAs indicated that these DE mRNAs might be associated with systemic lupus erythematosus, alcoholism, intestinal immune network for IgA production, inflammatory bowel disease, NF-kappa B signaling pathway. WGCNA and Pearson correlation analyses jointly identified 16,577 significantly correlated DE mRNA-lncRNA pairs. Furthermore, lncRNAs LINC00641, LINC02268, LINC03013 were identified as hub lncRNAs. The protein-protein interaction (PPI) network of proteins encoded by DE mRNAs was established, and PPI-based analysis revealed that Interleukin 2(IL2), CD80 molecule (CD80), interleukin-17A (IL-17A) might play significant roles in the development of STC. This study analyzes the expression profiles of lncRNAs and mRNAs associated with STC. Our findings will contribute to further understanding of the molecular mechanism of STC and provide potential diagnostic or therapeutic biomarkers for STC.

Efficacy and acceptability of different probiotic products plus laxatives for pediatric functional constipation: a network meta-analysis of randomized controlled trials

The prevalence of pediatric constipation ranges from 0.7 to 29.6% across different countries. Functional constipation accounts for 95% of pediatric constipation, and the efficacy of pharmacotherapy is limited, with a success rate of 60%. Several randomized controlled trials (RCTs) have shown the benefits of probiotic supplements in treating this condition. However, the reported strains of probiotics varied among the RCTs. We aimed to compare the efficacy and acceptability of different probiotic supplements for pediatric functional constipation. The current frequentist model-based network meta-analysis (NMA) included RCTs of probiotic supplements for functional constipation in children. The primary outcome was changes in bowel movement or stool frequency; acceptability outcome was all-cause discontinuation. Nine RCTs were included (N = 710; mean age = 5.5 years; 49.4% girls). Most probiotic products, used either alone or combined with laxatives, were associated with significantly better improvement in bowel movement or stool frequency than placebo/control. Protexin plus laxatives (standardized mean difference (SMD) = 1.87, 95% confidence interval (95% CI) = 0.85 to 2.90) were associated with the greatest improvement in bowel movement or stool frequency among all the investigated probiotic products. For the single probiotic interventions, only Lactobacillus casei rhamnosus Lcr35 was associated with significant efficacy compared to placebo/control treatments (SMD = 1.37, 95% CI: 0.32 to 2.43). All the investigated probiotic products had fecal incontinence and patient drop-out rates similar to those of placebo/control treatments.  Conclusion: The results of our NMA support the application of an advanced combination of probiotics and laxatives for pediatric functional constipation if there is no concurrent contraindication.  Registration: PROSPERO (CRD42022298724). What is Known: • Despite of the high prevalence of pediatric constipation, which ranges from 0.7% to 29.6%, the efficacy of pharmacotherapy is limited, with a success rate of 60%. Several randomized controlled trials (RCTs) have shown the benefits of probiotic supplements in treating this condition. However, the reported strains of probiotics varied among the RCTs. The widely heterogeneous strains of probiotics let the traditional meta-analysis, which pooled all different strains into one group, be nonsense and insignificant. What is New: • By conducting a comprehensive network meta-analysis, we aimed to compare the efficacy and acceptability of different strains of probiotic supplements for pediatric functional constipation. Network meta-analysis of nine randomized controlled trials revealed that the most probiotic products, used either alone or combined with laxatives, were associated with significantly better improvement in bowel movement or stool frequency than placebo/control. Protexin plus laxatives was associated with the greatest improvement in bowel movement or stool frequency among all the investigated probiotic products. For the single probiotic interventions, only Lactobacillus casei rhamnosus Lcr35 was associated with significant efficacy compared to placebo/control treatments. All the investigated probiotic products had fecal incontinence and patient drop-out rates similar to those of placebo/control treatments.

Transverse colon volvulus - a case report and literature review

SUMMARY

Transverse colon volvulus is a rare diagnosis, with less than 100 cases reported up to 2019. The condition is complicated by the absence of characteristic radiological findings and is typically diagnosed intraoperatively. It is a surgical emergency as the condition can lead to bowel necrosis and is associated with a mortality rate of up to 33%. Bowel resection is the treatment of choice, and if a megacolon is present a subtotal colectomy is recommended. Due to the rarity of transverse colon volvulus, limited data is available on the long-term outcome of patients.

Pathophysiological Implications of Interstitial Cajal-like Cells (ICC-like) in Uterus: A Comparative Study with Gastrointestinal ICCs

The main function of interstitial cells of Cajal (ICCs) is to regulate gastrointestinal peristalsis by acting as a "pacemaker" cell by generating spontaneous slow electrical waves. In 2005, electron microscopy revealed a cell type similar to ICCs (ICC-like) outside the gastrointestinal tract, with contractile activity and c-Kit+ immunohistochemistry shared with ICCs. Among the locations where ICC-like cells have been observed, it is in the uterus where they have a significant functional and pathophysiological role. These cells are involved in obstetric phenomena of contractile action, such as ascending sperm transport, embryo implantation, pregnancy, delivery, and the expulsion of menstrual debris. Within the pathophysiology related to these cells, we find obstetric alterations such as recurrent miscarriages, premature deliveries, abolition of uterine contractions, and failures of embryo implantation, in addition to other common conditions in the fertile age, such as endometriosis and leiomyoma.

Tracking Gut Motility in Organ and Cultures

Gastrointestinal (GI) motility is a key component of digestive health, and it is complex, involving a multitude of cell types and mechanisms to drive both rhythmic and arrhythmic activity. Tracking GI motility in organ and tissue cultures across multiple temporal (seconds, minutes, hours, days) scales can provide valuable information regarding dysmotility and to evaluate treatment options. Here, the chapter describes a simple method to monitor GI motility in organotypic cultures, using a single video camera is placed perpendicularly to the surface of the tissue. A cross-correlational analysis is used to track the relative movements of tissues between subsequent frames and subsequent fitting procedures to fit finite element functions to the deformed tissue to calculate the strain fields. Additional motility index measures from the displacement information are used to further quantify the behaviors of the tissues that are maintained in organotypic culture over days. The protocols presented in this chapter can be adapted to study organotypic cultures from other organs.

Inflammatory bowel disease-associated intestinal fibrosis

Fibrosis is characterized by a proliferation of fibroblasts and excessive extracellular matrix following chronic inflammation, and this replacement of organ tissue with fibrotic tissue causes a loss of function. Inflammatory bowel disease (IBD) is a chronic inflammation of the gastrointestinal tract, and intestinal fibrosis is common in IBD patients, resulting in several complications that require surgery, such as a stricture or penetration. This review describes the pathogenesis and various factors involved in intestinal fibrosis in IBD, including cytokines, growth factors, epithelial-mesenchymal and endothelial-mesenchymal transitions, and gut microbiota. Furthermore, histopathologic findings and scoring systems used for stenosis in IBD are discussed, and differences in the fibrosis patterns of ulcerative colitis and Crohn's disease are compared. Biomarkers and therapeutic agents targeting intestinal fibrosis are briefly mentioned at the end.

The Effects of Cognitive Behavioral Therapy with Biofeedback Therapy on the Quality of Life, Anxiety, Depression and Somatic Symptoms in Patients with Dyssynergic Defecation: A Randomized Controlled Trial

Background: Dyssynergic defecation (DD) is a major cause of chronic functional constipation. Patients with DD have greater psychological distress and impaired health-related quality of life compared with the general population. This study aimed to evaluate the effectiveness of cognitive-behavioral therapy (CBT) combined with biofeedback therapy (BFT) on the quality of life, anxiety, depression and physical symptoms in patients with DD.

Methods: This randomized controlled trial (IRCT20141115019957N2) was conducted on 45DD patients who were referred to the Rehabilitation Clinic of Iran University of Medical Sciences in 2017. The convenience sampling method was used to select the participants and then they were randomly allocated into three equal groups using RANDBETWEEN function in Excel. The first group received a combination of BFT&CBT and also standard-of-care therapy (SoCT). The second group was treated with BFT and SoCT, and the third group received only SoCT. The patients were assessed by digital rectal examination and the Short Form-36, Spielberger Anxiety, Beck Depression and Constipation Scoring System questionnaires before and after the treatment.The data were analyzed by SPSS-22, ANOVA, ANCOVA and Chi-Square tests.

Results: Patients who received both CBT&BFT had significant improvement in symptoms of constipation, depression, and anxiety.Furthermore, BFT and CBT&BFT groups are valued equivalent only on the mental component of SF36 and the total SF36 questionnaire. But the physical component was significantly different, favoring CBT&BFT (p< 0.001). In CBT&BFT group,67%of patients reached the relaxed stage. In contrast, no patient reached the relaxed neither in BFT nor in SoCT.

Conclusion: According to our study, patients with unfavorable responses to BFT may become better if CBT is added to their treatment plan.

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

Our understanding of human colonic motility, and autonomic reflexes that generate motor patterns, has increased markedly through high-resolution manometry. Details of the motor patterns are emerging related to frequency and propagation characteristics that allow linkage to interstitial cells of Cajal (ICC) networks. In studies on colonic motor dysfunction requiring surgery, ICC are almost always abnormal or significantly reduced. However, there are still gaps in our knowledge about the role of ICC in the control of colonic motility and there is little understanding of a mechanistic link between ICC abnormalities and colonic motor dysfunction. This review will outline the various ICC networks in the human colon and their proven and likely associations with the enteric and extrinsic autonomic nervous systems. Based on our extensive knowledge of the role of ICC in the control of gastrointestinal motility of animal models and the human stomach and small intestine, we propose how ICC networks are underlying the motor patterns of the human colon. The role of ICC will be reviewed in the autonomic neural reflexes that evoke essential motor patterns for transit and defecation. Mechanisms underlying ICC injury, maintenance, and repair will be discussed. Hypotheses are formulated as to how ICC dysfunction can lead to motor abnormalities in slow transit constipation, chronic idiopathic pseudo-obstruction, Hirschsprung's disease, fecal incontinence, diverticular disease, and inflammatory conditions. Recent studies on ICC repair after injury hold promise for future therapies.

Comparative Transcriptome Analysis Reveals Relationship among mRNAs, lncRNAs, and circRNAs of Slow Transit Constipation

Background

Slow transit constipation (STC) is characterized by persistent, infrequent, or incomplete defecation. Systematic analyses of mRNA, lncRNA, and circRNA expression profiling in STC provide insights to understand the molecular mechanisms of STC pathogenesis. The present study is aimed at observing the interaction of mRNAs, lncRNAs, and circRNAs by RNA sequencing in vivo of STC.

Methods

A rat model of STC was induced by loperamide. The expression profiles of both mRNAs and miRNAs were performed by RNA sequencing. Enrichment analyses of anomalous expressed mRNAs, lncRNAs, and circRNAs were performed in order to identify the related biological functions and pathologic pathways through the Gene Ontology (GO) database and Kyoto Encyclopedia of Genes and Genomes (KEGG) database.

Results

In total, 26435 mRNAs, 5703 lncRNAs, and 7708 circRNAs differentially expressed were identified between the two groups. The analyses of GO and KEGG show that (1) upregulated genes were enriched in a positive regulation of GTPase activity, cell migration, and protein binding and lipid binding and (2) GO annotations revealed that most trans-target mRNAs are involved in the regulation process of immune signal together with the proliferation and differentiation of immune cells. Additionally, the protein-protein interaction (PPI) network of differentially expressed (DE) mRNAs was constructed. Interestingly, all of the core lncRNAs and their coexpression mRNAs in this network are downregulated. Moreover, downregulated circRNAs have a set of target mRNAs related to immunoreaction, which was consistent with the overall tendency.

Conclusion

Our investigation enriches the STC transcriptome database and provides a preliminary exploration of novel candidate genes and avenues expression profiles in vivo. The dysregulation of mRNAs, lncRNAs, and circRNAs might contribute to the pathological processes during STC.

Nimodipine inhibits intestinal and aortic smooth muscle contraction by regulating Ca2+-activated Cl- channels

Nimodipine is a clinically used dihydropyridine L-type calcium channel antagonist that effectively inhibits transmembrane Ca2+ influx following the depolarization of smooth muscle cells, but the detailed effect on smooth muscle contraction is not fully understood. Ca2+-activated Cl- channels (CaCCs) in vascular smooth muscle cells (VSMCs) may regulate vascular contractility. We found that nimodipine can inhibit transmembrane protein 16A (TMEM16A) activity in a concentration-dependent manner by cell-based fluorescence-quenching assay and short-circuit current analysis, with an IC50 value of ~5 μM. Short-circuit current analysis also showed that nimodipine prevented Ca2+-activated Cl- current in both HT-29 cells and mouse colonic epithelia accompanied by significantly decreased cytoplasmic Ca2+ concentrations. In the absence of extracellular Ca2+, nimodipine still exhibited an inhibitory effect on TMEM16A/CaCCs. Additionally, the application of nimodipine to CFTR-expressing FRT cells and mouse colonic mucosa resulted in mild activation of CFTR-mediated Cl- currents. Nimodipine inhibited basolateral CCh-activated K+ channel activity with no effect on Na+/K+-ATPase activity. Evaluation of intestinal smooth muscle contraction showed that nimodipine inhibits intestinal smooth muscle contractility and frequency, with an activity pattern that was similar to that of non-specific inhibitors of CaCCs. In aortic smooth muscle, the expression of TMEM16A in thoracic aorta is higher than that in abdominal aorta, corresponding to stronger maximum contractility in thoracic aorta smooth muscle stimulated by phenylephrine (PE) and Eact. Nimodipine completely inhibited the contraction of aortic smooth muscle stimulated by Eact, and partially inhibited the contraction stimulated by PE. In summary, the results indicate that nimodipine effectively inhibits TMEM16A/CaCCs by reduction transmembrane Ca2+ influx and directly interacting with TMEM16A, explaining the mechanisms of nimodipine relaxation of intestinal and aortic smooth muscle contraction and providing new targets for pharmacological applications.

Electroacupuncture combined with Liumotang has beneficial effects on slow transit constipation in rats

BACKGROUND

The morbidity of slow transit constipation (STC) has been increasing year by year, but the efficacy of commonly used clinical treatments is not completely satisfactory. Studies have shown that traditional Chinese medicine, acupuncture, moxibustion, massage, and Chinese medicine application have achieved certain curative effects in the treatment of STC.

AIM

To investigate the therapeutic effects and mechanisms of electroacupunture combined with Liumotang on STC in rats.

METHODS

An STC rat model was established by feeding rats diphenoxylate, and then rats were treated with electroacupunture, Liumotang, or electroacupunture combined with Liumotang. After treatment, the general condition of rats was observed and the number of fecal pellets, fecal water content, and carbon propulsion rate were recorded. ELISA was used to assess the levels of serum nitric oxide (NO) and endothelial nitric oxide synthase (eNOS). The expression of aquaporin 3,8,9 (AQP3,8,9), c-kit, and stem cell factor (SCF) and the activity of PI3K/AKT pathway were evaluated by Western blot assay.

RESULTS

Compared with the electroacupunture group or Liumotang group, the treatment of electroacupunture combined with Liumotang could significantly increase the number of fecal pellets in 24 h, fecal water content, and carbon propulsion rate. Meanwhile, the combined treatment significantly decreased serum NO and eNOS levels in STC rats. Western blot results showed that the treatment of electroacupunture combined with Liumotang could up-regulate the protein expression of c-kit and SCF, while down-regulate the protein expression of AQP3, AQP8, and AQP9 in the colon tissue of STC rats. Furthermore, the phosphorylation of PI3K and AKT was promoted in the colon tissue of STC rats after the combined treatment.

CONCLUSION

Electroacupunture combined with Liumotang could relieve the symptoms of STC rats. And this therapeutic effect involves many targets, which is mainly related to regulating water and fluid metabolism, increasing gastrointestinal motility, and promoting gastrointestinal peristaltic.

Chronic constipation in adults: Contemporary perspectives and clinical challenges. 1: Epidemiology, diagnosis, clinical associations, pathophysiology and investigation

BACKGROUND

Chronic constipation is a prevalent disorder that affects patients' quality of life and consumes resources in healthcare systems worldwide. In clinical practice, it is still considered a challenge as clinicians frequently are unsure as to which treatments to use and when. Over a decade ago, a Neurogastroenterology & Motility journal supplement devoted to the investigation and management of constipation was published (2009; 21 (Suppl.2)). This included seven articles, disseminating all themes covered during a preceding 2-day meeting held in London, entitled "Current perspectives in chronic constipation: a scientific and clinical symposium." In October 2018, the 3rd London Masterclass, entitled "Contemporary management of constipation" was held, again over 2 days. All faculty members were invited to author two new review articles, which represent a collective synthesis of talks presented and discussions held during this meeting.

PURPOSE

This article represents the first of these reviews, addressing epidemiology, diagnosis, clinical associations, pathophysiology, and investigation. Clearly, not all aspects of the condition can be covered in adequate detail; hence, there is a focus on particular "hot topics" and themes that are of contemporary interest. The second review addresses management of chronic constipation, covering behavioral, conservative, medical, and surgical therapies.

Ethanol extract of Centella asiatica alleviated dextran sulfate sodium-induced colitis: Restoration on mucosa barrier and gut microbiota homeostasis

ETHNOPHARMACOLOGICAL RELEVANCE

Ulcerative colitis (UC) is a relapsing inflammatory disease that still demands for effective remedies due to various adverse effects of the current principal treatments. Centella asiatica is a traditional medical herb with long application history in anti-inflammation.

AIM OF THE STUDY

To explore the anti-inflammatory effect and possible mechanism of C. asiatica ethanol extract (CA) in a murine colitis model induced by dextran sulfate sodium (DSS).

MATERIALS AND METHODS

CA was analyzed by high performance liquid chromatograph (HPLC). The colitis model was induced by free access to 3% DSS in distilled water for 7 days. CA (100, 200, and 400 mg/kg) and 5-aminosalicylic acid (5-ASA, 400 mg/kg) were administrated by gavage during the 7-day DSS challenge. At the end of experiment, mice were sacrificed and the brain, colon and cecum contents were harvested for analysis. Colitis was evaluated by disease activity index (DAI), colon length and colon lesion macroscopic score with hematoxylin-eosin staining. Myeloperoxidase (MPO) activity in colon and 5-hydroxytryptamine (5-HT) in brain were determined by ELISA. Tight junction protein expressions (ZO-1, E-Cadherin, Claudin-1) and c-Kit in colon were assessed by western blot and immunohistochemistry, respectively. Microbiota of cecum content was analyzed by 16S rRNA sequencing.

RESULTS

Data showed that with recovery on the colon length and histological structure, CA prominently decreased DAI and macroscopic score for lesion in the suffering mice. CA relieved the colitis by suppressing inflammatory cell infiltration with decreased MPO activity in the colon, and up-regulated the expression of tight junction protein (ZO-1, E-cadherin) to enhance the permeability of intestinal mucosa. Moreover, CA restored intestinal motility by promoting c-Kit expression in the colon and 5-HT in the brain. Moreover, CA was able to reshape the gut microbiota in the suffering mice. It increased the α-diversity and shifted the community by depleting the colitis-associated genera, Helicobacter, Jeotgalicoccus and Staphylococcus, with impact on several metabolism signaling pathways, which possibly contributes to the renovation on the impaired intestinal mucosal barrier.

CONCLUSIONS

CA displayed the anti-inflammatory activity against the DSS-induced colitis, which would possibly rely on the restoration on mucosa barrier and gut microbiota homeostasis, highlights a promising application of C. asiatica in the clinical treatment of UC.

Functional Constipation: Individualising Assessment and Treatment

Chronic constipation is one of the five most common symptoms seen by gastroenterologist. In the absence of alarm symptoms, a confident symptom-based diagnosis can often be made using the Rome criteria. Three different subtypes have been identified to date: normal transit constipation, defaecatory disorders and slow transit constipation. Differentiation between these subtypes can be made through functional testing using tests such as anorectal manometry with balloon expulsion and a radio-opaque marker test. In general, patients are initially advised to increase their fluid and fibre intake. When these general lifestyle recommendations do not improve patients' symptoms, a step-wise and add-on treatment approach should be applied. This review summarises the diagnostic criteria to differentiate functional constipation from other causes of chronic constipation. In addition, current drug treatment options, including discussion of new therapeutic targets are discussed. Further, practical treatment approaches (choice and dosing), include discussion of combination/augmentation, treatment failure (adherence/expectations), and relapse prevention are mentioned. Finally, treatment and management of pain and bloating aspects are included.

The cyclic motor patterns in the human colon

BACKGROUND

High-resolution colonic manometry gives an unprecedented window into motor patterns of the human colon. Our objective was to characterize motor activities throughout the entire colon that possessed persistent rhythmicity and spanning at least 5 cm.

METHODS

High-resolution colonic manometry using an 84-channel water-perfused catheter was performed in 19 healthy volunteers. Rhythmic activity was assessed during baseline, proximal balloon distention, meal, and bisacodyl administration.

KEY RESULTS

Throughout the entire colon, a cyclic motor pattern occurred either in isolation or following a high-amplitude propagating pressure wave (HAPW), consisting of clusters of pressure waves at a frequency centered on 11-13 cycles/min, unrelated to breathing. The cluster duration was 1-6 minutes; the pressure waves traveled for 8-27 cm, lasting 5-8 seconds. The clusters itself could be rhythmic at 0.5-2 cpm. The propagation direction of the individual pressure waves was mixed with >50% occurring simultaneous. This high-frequency cyclic motor pattern co-existed with the well-known low-frequency cyclic motor pattern centered on 3-4 cpm. In the rectum, the low-frequency cyclic motor pattern dominated, propagating predominantly in retrograde direction. Proximal balloon distention, a meal and bisacodyl administration induced HAPWs followed by cyclic motor patterns.

CONCLUSIONS AND INFERENCES

Within cyclic motor patterns, retrograde propagating, low-frequency pressure waves dominate in the rectum, likely keeping the rectum empty; and mixed propagation, high-frequency pressure waves dominate in the colon, likely promoting absorption and storage, hence contributing to continence. Propagation and frequency characteristics are likely determined by network properties of the interstitial cells of Cajal.

Role of Tenascin-X in regulating TGF-β/Smad signaling pathway in pathogenesis of slow transit constipation

BACKGROUND

Chronic constipation is a gastrointestinal functional disease that seriously harms physical and mental health and impacts the quality of life of patients. Its incidence rate is 2%-27%. Slow transit constipation (STC) is a common type of chronic functional constipation, accounting for 10.3%-45.5% of such cases. Scholars have performed many studies on the pathogenesis of STC. These studies have indicated that the occurrence of STC may be related to multiple factors, such as dysfunction of the enteric nervous system, interstitial cells of Cajal (ICC) damage, and changes in neurotransmitters regulating intestinal peristalsis.

AIM

To investigate the role of Tenascin-X (TNX) in regulating the TGF-β/Smad signaling pathway in the pathogenesis of STC.

METHODS

This study included an experimental group and a control group. The experimental group included 28 patients with severe colonic STC, and the control group included 18 patients with normal colon tissues. Immunohistochemistry (IHC) was used to detect c-Kit, a specific marker of the ICC. Western blot, immunofluorescence, and IHC were used to detect the localization and expression of TNX and TGF-β/Smad.

RESULTS

IHC showed that the number of ICC with positive c-Kit expression was significantly reduced in the colon of STC patients (22.17 ± 3.28 vs 28.69 ± 3.53, P < 0.05) and that the distribution was abnormal. Western blot results showed that c-Kit and Smad7 levels were significantly decreased in the colon of STC patients (c-kit: 0.462 ± 0.099 vs 0.783 ± 0.178, P < 0.01; Smad7: 0.626 ± 0.058 vs 0.799 ± 0.03, P < 0.01) and that TNX and Smad2/3 levels were higher in the STC group (TNX: 0.868 ± 0.028 vs 0.482 ± 0.032, P < 0.01). There was no significant difference in TGF-β between the two groups (0.476 ± 0.028 vs 0.511 ± 0.044, P = 0.272). Pearson correlation analysis showed that the TNX protein exhibited a strong correlation with Smad2/3 and Smad7 (P < 0.05, |R| > 0.8) and TGF-β (P < 0.05, |R| = 0.7).

CONCLUSION

The extracellular matrix protein TNX may activate the TGF-β/Smad signaling pathway by upregulating the Smad 2/3 signaling protein and thereby induce slight or complete epithelial stromal cell transformation, leading to an abnormal distribution and dysfunction of ICC in the diseased colon, which promotes the occurrence and development of STC.

Associations Between Colonic Motor Patterns and Autonomic Nervous System Activity Assessed by High-Resolution Manometry and Concurrent Heart Rate Variability

Abnormal colonic motility may be associated with dysfunction of the autonomic nervous system (ANS). Our aim was to evaluate if associations between colonic motor patterns and autonomic neural activity could be demonstrated by assessing changes in heart rate variability (HRV) in healthy volunteers. A total of 145 colonic motor patterns were assessed in 11 healthy volunteers by High-Resolution Colonic Manometry (HRCM) using an 84-channel water-perfused catheter. Motor patterns were evoked by balloon distention, a meal and luminal bisacodyl. The electrocardiogram (ECG) and cardiac impedance were assessed during colonic manometry. Respiratory sinus arrhythmia (RSA) and root mean square of successive differences of beat-to-beat intervals (RMSSD) served as measures of parasympathetic reactivity while the Baevsky's Stress Index (SI) and the pre-ejection period (PEP) were used as measures of sympathetic reactivity. Taking all motor patterns into account, our data show that colonic motor patterns are accompanied by increased parasympathetic activity and decreased sympathetic activity that may occur without eliciting a significant change in heart rate. Motor Complexes (more than one motor pattern occurring in close proximity), High-Amplitude Propagating Pressure Waves followed by Simultaneous Pressure Waves (HAPW-SPWs) and HAPWs without SPWs are all associated with an increase in RSA and a decrease in SI. Hence RSA and SI may best reflect autonomic activity in the colon during these motor patterns as compared to RMSSD and PEP. SI and PEP do not measure identical sympathetic reactivity. The SPW, which is a very low amplitude pressure wave, did not significantly change the autonomic measures employed here. In conclusion, colonic motor patterns are associated with activity in the ANS which is reflected in autonomic measures of heart rate variability. These autonomic measures may serve as proxies for autonomic neural dysfunction in patients with colonic dysmotility.

Subtotal colectomy and ileorectal anastomosis for slow transit constipation: clinical follow-up at median of 15 years

BACKGROUND

Slow transit constipation is characterised by prolonged colonic transit and reliance on laxatives. The pathophysiology is poorly understood and in its most severe form, total colectomy with ileorectal anastomosis is the final treatment option. We present a follow-up study of the long-term function in patients who had surgery for laxative-resistant slow transit constipation.

METHODS

A postal survey was sent to assess bowel frequency, abdominal pain, St Mark's continence score, satisfaction with procedure, likelihood to choose the procedure again, and long-term rates of small bowel obstruction and ileostomy. Longitudinal data from a subgroup studied 23 years previously are reported.

RESULTS

Forty-two patients (male = 2) were available for follow-up out of an initial cohort of 102. Mean time since surgery was 15.9 years (range 1.7-29.7) years. Fifty percent had < 4 bowel motions per day, most commonly Bristol stool 6, mean St Mark's score 7.45. Twenty-one percent had severe incontinence. Satisfaction and likelihood to choose surgery were high (median 10/10). There was a high rate of small bowel obstruction, suggesting pan-intestinal dysmotility in some cases. Conversion to ileostomy occurred in 8 patients. In the longitudinal follow-up in 15 subjects, continence deteriorated (p < 0.01), stool consistency softened (p < 0.01), and stool frequency fell (p < 0.01).

CONCLUSIONS

Satisfactory stool frequency was achieved in the long term, and although 21% had incontinence scores > 12, patient satisfaction was high. This is the longest reported follow-up of colectomy for slow transit constipation, with longitudinal outcomes reported. There was considerable attrition of patients, so larger, longitudinal studies are required to better ascertain the functional outcomes of these patients.

Physiology of Electrolyte Transport in the Gut: Implications for Disease

We now have an increased understanding of the genetics, cell biology, and physiology of electrolyte transport processes in the mammalian intestine, due to the availability of sophisticated methodologies ranging from genome wide association studies to CRISPR-CAS technology, stem cell-derived organoids, 3D microscopy, electron cryomicroscopy, single cell RNA sequencing, transgenic methodologies, and tools to manipulate cellular processes at a molecular level. This knowledge has simultaneously underscored the complexity of biological systems and the interdependence of multiple regulatory systems. In addition to the plethora of mammalian neurohumoral factors and their cross talk, advances in pyrosequencing and metagenomic analyses have highlighted the relevance of the microbiome to intestinal regulation. This article provides an overview of our current understanding of electrolyte transport processes in the small and large intestine, their regulation in health and how dysregulation at multiple levels can result in disease. Intestinal electrolyte transport is a balance of ion secretory and ion absorptive processes, all exquisitely dependent on the basolateral Na⁺ /K⁺ ATPase; when this balance goes awry, it can result in diarrhea or in constipation. The key transporters involved in secretion are the apical membrane Cl^- channels and the basolateral Na⁺ -K⁺ -2Cl^- cotransporter, NKCC1 and K⁺ channels. Absorption chiefly involves apical membrane Na⁺ /H⁺ exchangers and Cl^- /HCO₃ ^- exchangers in the small intestine and proximal colon and Na⁺ channels in the distal colon. Key examples of our current understanding of infectious, inflammatory, and genetic diarrheal diseases and of constipation are provided. © 2019 American Physiological Society. Compr Physiol 9:947-1023, 2019.

Contractile dysfunction and nitrergic dysregulation in small intestine of a primate model of Parkinson's disease

Bowel dysfunction is a common non-motor symptom in Parkinson’s disease (PD). The main contractile neurotransmitter in the GI tract is acetylcholine (ACh), while nitric oxide (NO) causes the relaxation of smooth muscle in addition to modulating ACh release. The aim of this study was to characterise functional and neurochemical changes in the isolated ileum of the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-treated marmoset, an established model of PD motor dysfunction. While NO-synthase inhibitor L-NAME concentration dependently augmented the neurogenically-evoked contractions and inhibited the relaxations in normal tissues, it had no effects on the MPTP ileum. Immunohistochemical analyses of the myenteric plexus showed that ChAT-immunoreactivity (-ir) was significantly reduced and the density of the enteric glial cells as shown by SOX-10-ir was increased. However, no change in TH-, 5-HT-, VIP- or nNOS-ir was observed in the MPTP tissues. The enhancement of the neurogenically-evoked contractions and the inhibition of the relaxation phase by L-NAME in the control tissues is in line with NO’s direct relaxing effect on smooth muscle and its indirect inhibitory effect on ACh release. The absence of the relaxation and the inefficacy of L-NAME in the MPTP tissues suggests that central dopaminergic loss dopamine may eventually lead to the impairment of NO signal coupling that affects bowel function, and this may be the result of a complex dysregulation at the level of the neuroeffector junction.

Manometric recordings bring out post-stimulus refractory states in the anal canal in neonates

Anorectal manometry is a diagnostic technique used to investigate the correct mechanical performance of the internal anal sphincter (IAS). By distending the rectal ampulla while recording changes in the luminal pressure, this method allows for characterizing the anorectal reflex. It can also provide, indirectly, information about the electrical activity of the IAS. In this study, seventeen neonates having 24-hour delayed passage of meconium or presenting distal intestinal obstruction symptoms underwent anorectal manometry to discard Hirschsprung's disease. All patients had normal anorectal reflex. The time delay between stimulation of the rectal ampulla and the relaxation of the anal canal was studied. The average period of the pressure fluctuations was 5.44 ± 0.13s. The overall duration of the relaxation time was 9.71 ± 0.21s. The maximum lag between the onset of the stimulus and the relaxation of the IAS was 2.90 s, and was achieved when the stimulus was applied following a local maximum of the pressure wave. The existence of a refractory period during the suprathreshold depolarization of smooth muscle cells can explain the evidence of a temporal delay between the stimulus and the mechanical response. In occasions, relaxation appeared first distally. This phenomenon can be explained by the arrangement and morphology of bipolar cells, which may evidence the anisotropic propagation of the mechanical activity. These data may contribute to depict the alterations in excitability underlying the relaxation reflex by means of manometric recording of the anal canal.

The "rectosigmoid brake": Review of an emerging neuromodulation target for colorectal functional disorders

The regulation of gastrointestinal motility encompasses several overlapping mechanisms including highly regulated and coordinated neurohormonal circuits. Various feedback mechanisms or "brakes" have been proposed. While duodenal, jejunal, and ileal brakes are well described, a putative distal colonic brake is less well defined. Despite the high prevalence of colonic motility disorders, there is little knowledge of colonic motility owing to difficulties with organ access and technical difficulties in recording detailed motor patterns along its entire length. The motility of the colon is not under voluntary control. A wide range of motor patterns is seen, with long intervals of intestinal quiescence between them. In addition, the use of traditional manometric catheters to record contractile activity of the colon has been limited by the low number of widely spaced sensors, which has resulted in the misinterpretation of colonic motor patterns. The recent advent of high-resolution (HR) manometry is revolutionising the understanding of gastrointestinal motor patterns. It has now been observed that the most common motor patterns in the colon are repetitive two to six cycles per minute (cpm) propagating events in the distal colon. These motor patterns are prominent soon after a meal, originate most frequently in the rectosigmoid region, and travel in the retrograde direction. The distal prominence and the origin of these motor patterns raise the possibility of them serving as a braking mechanism, or the "rectosigmoid brake," to limit rectal filling. This review aims to describe what is known about the "rectosigmoid brake," including its physiological and clinical significance and potential therapeutic applications.

Indian consensus on chronic constipation in adults: A joint position statement of the Indian Motility and Functional Diseases Association and the Indian Society of Gastroenterology

The Indian Motility and Functional Diseases Association and the Indian Society of Gastroenterology developed this evidence-based practice guideline for management of chronic constipation. A modified Delphi process was used to develop this consensus containing 29 statements, which were generated by electronic voting iteration as well as face to face meeting and review of the supporting literature primarily from India. These statements include 9 on epidemiology, clinical presentation, and diagnostic criteria; 8 on pathophysiology; and the remaining 12 on investigations and treatment. When the proportion of those who voted either to accept completely or with minor reservation was 80% or higher, the statement was regarded as accepted. The members of the consensus team believe that this would be useful for teaching, clinical practice, and research on chronic constipation in India and in other countries with similar spectrum of the disorders.

Efficacy and Predictors for Biofeedback Therapeutic Outcome in Patients with Dyssynergic Defecation

Aim

To evaluate the short-term efficacy of biofeedback therapy (BFT) for dyssynergic defecation (DD) and to explore the predictors of the efficacy of BFT.

Methods

Clinical symptoms, psychological state, and quality of life of patients before and after BFT were investigated. All patients underwent lifestyle survey and anorectal physiology tests before BFT. Improvement in symptom scores was considered proof of clinical efficacy of BFT. Thirty-eight factors that could influence the efficacy of BFT were studied. Univariate and multivariate analysis was conducted to identify the independent predictors.

Results

Clinical symptoms, psychological state, and quality of life of DD patients improved significantly after BFT. Univariate analysis showed that efficacy of BFT was positively correlated to one of the 36-item Short-Form Health Survey terms, the physical role function (r = 0.289; P = 0.025), and negatively correlated to the stool consistency (r = −0.220; P = 0.032), the depression scores (r = −0.333; P = 0.010), and the first rectal sensory threshold volume (r = −0.297; P = 0.022). Multivariate analysis showed depression score (β = −0.271; P = 0.032) and first rectal sensory threshold volume (β = −0.325; P = 0.013) to be independent predictors of BFT efficacy.

Conclusion

BFT improves the clinical symptoms of DD patients. Depression state and elevated first rectal sensory threshold volume were independent predictors of poor outcome with BFT.

Intractable Constipation in the Elderly

OPINION STATEMENT

Chronic constipation is a common gastrointestinal disorder disproportionately affecting the elderly. Immobility, polypharmacy, and physiologic changes contribute to its increased prevalence in this population. Unidentified and undertreated constipation leads to a significant negative impact on quality of life and an increase in healthcare spending. Careful physical examination and exploration of the clinical history can unmask primary and secondary forms of constipation, guiding diagnostic and therapeutic considerations. Non-pharmacologic treatment options include bowel training and biofeedback as well as the addition of fiber. Laxatives are safe and can be used long term; thus, they remain the mainstay of therapy. Newer agents with specific physiologic targets have proven to be effective in adults with chronic constipation, but data is lacking for safety profile in the elderly. Consideration for surgery in medically refractory cases should be entertained, while use of neuromodulation is not ready for prime time. This is a review of the currently available treatment options for chronic constipation in adults and specifically tailored towards the elderly.

Luminally Acting Agents for Constipation Treatment: A Review Based on Literatures and Patents

Constipation is one of the most frequently reported gastrointestinal (GI) disorders that negatively impacts quality of life and is associated with a significant economic burden to the patients and society. Traditional treatments including lifestyle modification and laxatives are often ineffective in the more severe forms of constipation and over the long term. New medications targeting at intestinal chloride channels and colonic serotonin receptors have been demonstrated effective in recent years. Emerging agents focusing on improving intestinal secretion and/or colonic motility have been shown effective in animal models and even in clinical trials. Recognization of the role of cystic fibrosis transmembrane regulator (CFTR) and calcium-activated chloride channels (CaCCs) in intestine fluid secretion and motility modulation makes CFTR and CaCCs promising molecule targets for anti-constipation therapy. Although there are multiple choices for constipation treatment, there is still a recognized need for new medications in anti-constipation therapy. The present review covers the discovery of luminally acting agents for constipation treatment described in both patents (2011–present) and scientific literatures.

Acute large bowel pseudo-obstruction due to atrophic visceral myopathy: A case report

PURPOSE

Atrophic visceral myopathy is a pathological diagnosis characterized by atrophy of the smooth muscle layers of the viscera with intact ganglia. Rarely, it can present acutely as an intestinal pseudo-obstruction. We describe a rare case report and explore how this diagnosis can be distinguished from other forms of intestinal obstruction.

CASE DESCRIPTION

A 60-year-old male with a past medical history of hypothyroidism presented to the emergency department with a two-day history of worsening abdominal distention and pain associated with nausea and vomiting. Upon evaluation patient was found to have tachycardia, with abdominal distention and localized tenderness with peritonitis. Computed tomography demonstrated large bowel obstruction, likely caused by sigmoid volvulus. The patient underwent emergent laparotomy. Intra-operatively, the entire colon was found to be extremely dilated and redundant. With a working diagnosis of recurrent sigmoid volvulus causing intermittent large bowel obstruction, a sigmoid colectomy and primary anastomosis was performed. Pathology revealed atrophic visceral myopathy, with an extremely thin colonic wall and atrophic circumferential and longitudinal muscularis propria without inflammation or fibrosis. The ganglion cells and myenteric plexus were unaffected. Post-operatively, the patient developed prolonged ileus requiring nasogastric decompression and parenteral nutrition. The ileus resolved with pro-kinetic agents, and patient was discharged home on post-operative day fifteen.

CONCLUSIONS

Atrophic visceral neuropathy is a rare cause of intestinal pseudo-obstruction. While often presenting with chronic obstruction in younger populations, we present a rare late-onset acute presentation that may have been secondary to underlying hypothyroidism.

Functional constipation in children: challenges and solutions

This review intends to update what is known about and what is still a challenge in functional constipation (FC) in children regarding epidemiology, pathophysiology, diagnosis, and management. Although FC is a common childhood problem, its global burden remains unknown as data from parts of the world are missing. Another problem is that there is a large variation in prevalence due to differences in study methods and defining age groups. The pathophysiology of FC remains unclear to date but is probably multifactorial. Withholding behavior is likely to be the most important factor in toddlers and young children. Genetics may also play a role since many patients have positive family history, but mutations in genes associated with FC have not been found. Over the past years, different diagnostic criteria for FC in infants and children have been proposed. This year, Rome IV criteria have been released. Compared to Rome III, it eliminates two diagnostic criteria in children under the age of 4 who still wear diapers. Physical examination and taking a thorough medical history are recommended, but other investigations such as abdominal radiography, transabdominal recto-ultrasonography, colonic transit time, rectal biopsies, and colon manometry are not routinely recommended. Regarding treatment, guidelines recommend disimpaction and maintenance therapy with polyethylene glycol (PEG) with or without electrolytes. But experience shows that acceptability, adherence, and tolerance to PEG are still a challenge. Counseling of parents and children about causes of FC is often neglected. Recent studies suggest that behavior therapy added to laxative therapy improves the relief of symptoms. Further homogeneous studies, better-defined outcomes, and studies conducted in primary care are needed.

Intraluminal pressure patterns in the human colon assessed by high-resolution manometry

Assessment of colonic motor dysfunction is rarely done because of inadequate methodology and lack of knowledge about normal motor patterns. Here we report on elucidation of intraluminal pressure patterns using High Resolution Colonic Manometry during a baseline period and in response to a meal, in 15 patients with constipation, chronically dependent on laxatives, 5 healthy volunteers and 9 patients with minor, transient, IBS-like symptoms but no sign of constipation. Simultaneous pressure waves (SPWs) were the most prominent propulsive motor pattern, associated with gas expulsion and anal sphincter relaxation, inferred to be associated with fast propagating contractions. Isolated pressure transients occurred in most sensors, ranging in amplitude from 5–230 mmHg. Rhythmic haustral boundary pressure transients occurred at sensors about 4–5 cm apart. Synchronized haustral pressure waves, covering 3–5 cm of the colon occurred to create a characteristic intrahaustral cyclic motor pattern at 3–6 cycles/min, propagating in mixed direction. This activity abruptly alternated with erratic patterns resembling the segmentation motor pattern of the small intestine. High amplitude propagating pressure waves (HAPWs) were too rare to contribute to function assessment in most subjects. Most patients, dependent on laxatives for defecation, were able to generate normal motor patterns in response to a meal.

Genetics of enteric neuropathies

Abnormal development or disturbed functioning of the enteric nervous system (ENS), the intrinsic innervation of the gastrointestinal tract, is associated with the development of neuropathic gastrointestinal motility disorders. Here, we review the underlying molecular basis of these disorders and hypothesize that many of them have a common defective biological mechanism. Genetic burden and environmental components affecting this common mechanism are ultimately responsible for disease severity and symptom heterogeneity. We believe that they act together as the fulcrum in a seesaw balanced with harmful and protective factors, and are responsible for a continuum of symptoms ranging from neuronal hyperplasia to absence of neurons.

Diagnosis and management of chronic constipation in adults

Constipation is a heterogeneous, polysymptomatic, multifactorial disease. Acute or transient constipation can be due to changes in diet, travel or stress, and secondary constipation can result from drug treatment, neurological or metabolic conditions or, rarely, colon cancer. A diagnosis of primary chronic constipation is made after exclusion of secondary causes of constipation and encompasses several overlapping subtypes. Slow-transit constipation is characterized by prolonged colonic transit in the absence of pelvic floor dysfunction. This subtype of constipation can be identified using either the radio-opaque marker test or wireless motility capsule test, and is best treated with laxatives such as polyethylene glycol or newer agents such as linaclotide or lubiprostone. If unsuccessful, subspecialist referral should be considered. Dyssynergic defecation results from impaired coordination of rectoanal and pelvic floor muscles, and causes difficulty with defecation. The condition can be identified using anorectal manometry and balloon expulsion tests and is best managed with biofeedback therapy. Opioid-induced constipation is an emerging entity, and several drugs including naloxegol, methylnaltrexone and lubiprostone are approved for its treatment. In this Review, we provide an overview of the burden and pathophysiology of chronic constipation, as well as a detailed discussion of the available diagnostic tools and treatment options.

Clinical aspects of neurointestinal disease: Pathophysiology, diagnosis, and treatment

The enteric nervous system (ENS) is involved in the regulation of virtually all gut functions. Conditions referred to as enteric neuropathies are the result of various mechanisms including abnormal development, degeneration or loss of enteric neurons that affect the structure and functional integrity of the ENS. In the past decade, clinical and molecular research has led to important conceptual advances in our knowledge of the pathogenetic mechanisms of these disorders. In this review we consider ENS disorders from a clinical perspective and highlight the advancing knowledge regarding their pathophysiology. We also review current therapies for these diseases and present potential novel reparative approaches for their treatment.

The origin of segmentation motor activity in the intestine

The segmentation motor activity of the gut that facilitates absorption of nutrients, was first described in the late 19th century but the fundamental mechanisms underlying it remain poorly understood. The dominant theory suggests alternate excitation and inhibition from the enteric nervous system. Here we demonstrate that typical segmentation can occur after total nerve blockade. The segmentation motor pattern emerges when the amplitude of the dominant pacemaker, the slow wave generated by ICC associated with the myenteric plexus (ICC-MP), is modulated by the phase of induced lower frequency rhythmic transient depolarizations, generated by ICC associated with the deep muscular plexus (ICC-DMP), resulting in a waxing and waning of the amplitude of the slow wave and a rhythmic checkered pattern of segmentation motor activity. Phase amplitude modulation of the slow waves points to an underlying system of coupled nonlinear oscillators originating in ICC.

Chronic constipation in the elderly: a primer for the gastroenterologist

Constipation is a frequently reported bowel symptom in the elderly with considerable impact on quality of life and health expenses. Disease-related morbidity and even mortality have been reported in the affected frail elderly. Although constipation is not a physiologic consequence of normal aging, decreased mobility, medications, underlying diseases, and rectal sensory-motor dysfunction may all contribute to its increased prevalence in older adults. In the elderly there is usually more than one etiologic mechanism, requiring a multifactorial treatment approach. The majority of patients would respond to diet and lifestyle modifications reinforced by bowel training measures. In those not responding to conservative treatment, the approach needs to be tailored addressing all comorbid conditions. In the adult population, the management of constipation continues to evolve as well as the understanding of its complex etiology. However, the constipated elderly have been left behind while gastroenterology consultations for this common conditions are at a rise for the worldwide age increment. Aim of this review is to provide an update on epidemiology, quality of life burden, etiology, diagnosis, current approaches and limitations in the management of constipation in the older ones to ease the gastroenterologists’ clinic workload.

Molecular and Cellular Characteristics of the Colonic Pseudo-obstruction in Patients With Intractable Constipation

BACKGROUND/AIMS

Chronic intestinal pseudo-obstruction (CIPO) is a disorder characterized by recurrent symptoms suggestive of obstruction such as abdominal pain, proximal distension with extremely suppressed motility in the absence of lumen-occluding lesion, whose etiology/ pathophysiology is poorly understood. In this study we investigated a functionally obstructive lesion that could underlie symptoms of CIPO.

METHODS

We studied colons surgically removed from 13 patients exhibiting clinical/pathological features of pseudo-obstruction but were unresponsive to standard medical treatments. The colons were characterized morphologically, functionally and molecularly, which were compared between regions and to 28 region-matched controls obtained from colon cancer patients.

RESULTS

The colons with pseudo-obstruction exhibited persistent luminal distension proximally, where the smooth muscle was hypertrophied with changes in the cell phenotypes. Distinct luminal narrowing was observed near the distal end of the dilated region, close to the splenic flexure, previously referred to as the "transition zone (TZ)" between the dilated and non-dilated loops. Circular muscles from the TZ responded less to depolarization and cholinergic stimulation, which was associated with downregulation of L-type calcium channel expression. Smooth muscle contractile protein was also downregulated. Myenteric ganglia and neuronal nitric oxide synthase (nNOS) positive cells were deficient, more severely in the TZ region. Interstitial cells of Cajal was relatively less affected.

CONCLUSIONS

The TZ may be the principal site of functional obstruction, leading to proximal distension and smooth muscle hypertrophy, in which partial nNOS depletion could play a key role. The neuromuscular abnormalities probably synergistically contributed to the extremely suppressed motility observed in the colonic pseudo-obstruction.

Comparison of two types of colectomy in treating slow transit constipation with or without melanosis coli

AIM: To compare the follow-up outcomes of ileosigmoidal anastomosis (ISA) and caecorectal anastomosis (CRA) in patients with slow transit constipation (STC) with or without melanosis coli (MC).

METHODS: We collected the clinical data of 48 STC patients with or without MC from May 2002 to May 2007. Twenty-six patients underwent CRA (14 with MC) and 22 cases received ISA (14 with MC). A 3-year postoperative follow-up was conducted.

RESULTS: CRA improved the quality of life [evaluated by the gastrointestinal quality of life index (GIQLI)] in patients without MC, but was inferior to ISA in stool frequency and Wexner and GIQLI scores for MC patients. In the CRA group, patients with MC suffered worse outcomes than those without MC.

CONCLUSION: CRA is more suitable for STC patients without MC; however, for STC patients with MC, ISA is a better choice.

Sigmoid volvulus is associated with a decrease in enteric plexuses and ganglion cells: a case-control study

PURPOSE

Although sigmoid volvulus (SV) causes acute obstruction, its pathogenesis and mechanism of torsion are unknown, and few reports have described its pathological findings. Here, we evaluated the clinicopathological characteristics of volvulus and factors contributing to volvulus of the sigmoid colon.

METHODS

We compared 14 patients with SV (10 men and 4 women; median age, 78.5 years) with 14 age- and sex-matched control patients for differences in clinical characteristics, focusing on dysmotility (enteric visceral myopathy, neuropathy, and mesenchymopathy).

RESULTS

Of the 14 SV patients, 7 had recurrent volvulus, 11 had an associated condition, and 5 required emergency surgery. Atrophy and fibrosis of the inner muscle were more prevalent in the SV than control patients (p = 0.041). Median extent (per centimeter of muscularis propria) of the myenteric plexus (12.5 versus 17.5, p < 0.001) and submucous plexus (15.0 versus 25.5, p < 0.001) was lower in the SV patients, as were the median numbers of myenteric (9.7 versus 30.4, p < 0.001) and submucous ganglion cells (10.0 versus 23.2, p < 0.001). Inflammatory neuropathy was more prevalent in the SV than control patients (p = 0.046); whereas, the prevalence of mesenchymopathy did not differ (p = 0.481).

CONCLUSIONS

A decrease in the extent of enteric plexus and ganglion cells precedes the clinical manifestation of SV. Although further elucidation is needed, this decrease may play an important role in the diagnosis of SV and in identifying the mechanism leading to torsion in SV.

Interstitial cells: regulators of smooth muscle function

Smooth muscles are complex tissues containing a variety of cells in addition to muscle cells. Interstitial cells of mesenchymal origin interact with and form electrical connectivity with smooth muscle cells in many organs, and these cells provide important regulatory functions. For example, in the gastrointestinal tract, interstitial cells of Cajal (ICC) and PDGFRα(+) cells have been described, in detail, and represent distinct classes of cells with unique ultrastructure, molecular phenotypes, and functions. Smooth muscle cells are electrically coupled to ICC and PDGFRα(+) cells, forming an integrated unit called the SIP syncytium. SIP cells express a variety of receptors and ion channels, and conductance changes in any type of SIP cell affect the excitability and responses of the syncytium. SIP cells are known to provide pacemaker activity, propagation pathways for slow waves, transduction of inputs from motor neurons, and mechanosensitivity. Loss of interstitial cells has been associated with motor disorders of the gut. Interstitial cells are also found in a variety of other smooth muscles; however, in most cases, the physiological and pathophysiological roles for these cells have not been clearly defined. This review describes structural, functional, and molecular features of interstitial cells and discusses their contributions in determining the behaviors of smooth muscle tissues.

Interstitial cells of Cajal: update on basic and clinical science

The basic science and clinical interest in the networks of interstitial cells of Cajal (ICC) keep growing, and here, research from 2010 to mid-2013 is highlighted. High-resolution gastrointestinal manometry and spatiotemporal mapping are bringing exciting new insights into motor patterns, their function and their myogenic and neurogenic origins, as well as the role of ICC. Critically important knowledge is emerging on the partaking of PDGFRα+ cells in ICC pacemaker networks. Evidence is emerging that ICC and PDGFRα+ cells have unique direct roles in muscle innervation. Chronic constipation is associated with loss and injury to ICC, which is stimulating extensive research into maintenance and repair of ICC after injury. In gastroparesis, high-resolution electrical and mechanical studies are beginning to elucidate the pathophysiological role of ICC and the pacemaker system in this condition. Receptors and ion channels that play a role in ICC function are being discovered and characterized, which paves the way for pharmacological interventions in gut motility disorders through ICC.

Neural stem cell therapies for enteric nervous system disorders

The enteric nervous system is vulnerable to a range of congenital and acquired disorders that disrupt the function of its neurons or lead to their loss. The resulting enteric neuropathies are some of the most challenging clinical conditions to manage. Neural stem cells offer the prospect of a cure given their potential ability to replenish missing or dysfunctional neurons. This article discusses diseases that might be targets for stem cell therapies and the barriers that could limit treatment application. We explore various sources of stem cells and the proof of concept for their use. The critical steps that remain to be addressed before these therapies can be used in patients are also discussed. Key milestones include the harvesting of neural stem cells from the human gut and the latest in vivo transplantation studies in animals. The tremendous progress in the field has brought experimental studies exploring the potential of stem cell therapies for the management of enteric neuropathies to the cusp of clinical application.

Histopathologic findings in patients with idiopathic megacolon: a comparison between dilated and non-dilated loops

BACKGROUND

Idiopathic megacolon (IMC) is an intractable motility disorder in which chronic symptoms of colonic dysmotility appear with no mechanical cause. Although a pathological analysis is essential to understand the mechanism of IMC, no study has compared the histopathologic findings between dilated and non-dilated loops in IMC cases, and little is known about the proportion of each disease subtype.

METHODS

Fifty-three full-thickness samples (dilated loops, n = 31; non-dilated loops, n = 22) from 31 IMC cases and 16 samples (dilated loops; n = 8, non-dilated loops; n = 8) from eight controls were collected. All the samples were stained with hematoxylin-eosin (HE), Hu C/D antibody, and CD117 antibody to assess degenerative myopathy, degenerative neuropathy, inflammatory neuropathy, hypoganglionosis, and mesenchymopathy according to the London Classification. Findings of the dilated and non-dilated loop samples were compared, and the proportions of each subtype were analyzed.

KEY RESULTS

Based on a control study, <60 ganglion cells/cm was defined as hypoganglionosis in our series. Myopathy was observed in 11 patients (35.5%), neuropathy was in 19 patients (61.3%), and mesenchymopathy was in 10 patients (32.2%). An overlap between subtypes was observed in some cases. Surprisingly, the non-dilated loop samples exhibited very similar histopathologic abnormalities to those observed in the dilated loop samples in most cases.

CONCLUSIONS & INFERENCES

Our study is the first to compare the histopathologic findings between dilated and non-dilated loops in IMC patients. Histopathologic abnormalities precede the clinical manifestation of IMC, and may consequently lead to gradual colonic dilatation; however, detailed mechanism including dilation triggering factor needs further elucidation.

A modified total colonic exclusion for elderly patients with severe slow transit constipation

BACKGROUND

The aim of this study was to evaluate outcomes of total colonic exclusion with antiperistaltic ileorectal anastomosis (TCE-AIA) for elderly patients with slow transit constipation (STC).

METHODS

Elderly patients (defined as age >65) who underwent TCE-AIA for severe idiopathic STC between 2009 and 2012 at our institution were identified. Postoperative outcomes and routine follow-up were assessed using the Wexner constipation score (WCS), gastrointestinal quality of life index (GIQLI) and four-point postoperative satisfaction scales.

RESULTS

A total of 13 elderly patients were met the inclusion criteria. Five patients (38.5%) were male, and eight patients (61.5%) were female. The mean age of this population was 74 years (range 63-82 years). The mean operative time was 55 min (range 28-32), and blood loss was minimal. The mean postoperative hospital stay was 6.7 days (range 5-12 days). The mean time until the first postoperative bowel movement was 4 days (range 2-8 days). There was no procedure-related mortality and no major in-hospital complications. The median duration of follow-up was 12.4 months (range 6-29 months). None of the 13 patients had fecal incontinence or recurrence of constipation at the follow-up end point. However, eight patients underwent colonoscopy during follow-up, and four patients presented with diversion colitis. The patients' preoperative WCS was 22.8 ± 3.3, and it had significantly improved to 5.4 ± 2.1 on 6 months after operation (p < 0.05). The preoperative GIQLI of 93.6 ± 20.5 had significantly increased to 120.8 ± 13.0 on 6 months after surgery (p < 0.05). Patient satisfaction at 6 months was very high in 11 patients and high in two patients.

CONCLUSIONS

TCE-AIA is a relatively simple procedure. It might be an effective surgical intervention for the selected elderly patients with STC.

Chronic constipation in the elderly: an unusual presentation of colonic dysmotility in an elderly patient

Introduction. Chronic constipation is common in the elderly, and often no underlying pathology is found. Primary colonic dysmotility has been described in children but is rare in the elderly. Case report. We present an 82-year-old female with long standing constipation presenting acutely with large bowel obstruction. Laparotomy and Hartman's procedure was performed, and a grossly distended sigmoid colon was resected. Histology revealed a primary myopathic process. Conclusion. Primary colonic myopathy should be considered in elderly patients presenting with large bowel obstruction and a long preceding history of constipation, particularly when previous endoscopic examinations were normal.