Idiopathic Slow Transit Constipation: Pathophysiology, Diagnosis, and Management

Meta-analysis of Randomized Controlled Trials on the Efficacy of Sacral Neuromodulation in Chronic Constipation

OBJECTIVES

The present systematic review aimed to assess the outcome of sacral neuromodulation (SNM) in adult patients with chronic constipation.

MATERIALS AND METHODS

A systematic review of randomized controlled trials (RCTs) that assessed the efficacy of SNM in chronic constipation was conducted and reported following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2020 guideline. PubMed, Scopus, and Web of Science were screened from their inception through March 2024. The primary outcome was improvement in constipation and quality of life (QoL), and the secondary outcome was adverse events after treatment. The risk of bias and certainty of evidence were assessed by the risk of bias 2 tool and Grading of Recommendations Assessment, Development, and Evaluation approach.

RESULTS

Five RCTs incorporating 187 patients (93.6% female) with a median age of 42.5 years were included; 154 patients underwent SNM whereas 86 patients were crossed over to sham stimulation, and 33 received conservative treatment, amounting to a control group of 119 patients. The odds of relief of constipation after SNM were similar to those in the control group in the random-effect model (odds ratio [OR]: 1.92, 95% CI: 0.68-5.42, p = 0.217). The median percentage of reduction in the Cleveland Clinic Florida/Wexner Constipation Score was 27.9% in the SNM group vs 18.4% in the control group. No significant differences were observed in QoL. Both groups had similar odds of adverse events (OR: 2.22, 95% CI: 0.19-25.53, p = 0.521).

CONCLUSION

Although a relatively safe treatment, SNM was not associated with any tangible improvements in either constipation or QoL.

Poly-γ-glutamic acid alleviates slow transit constipation by regulating aquaporin and gut microbes

Slow transit constipation (STC) is a prevalent gastrointestinal disorder caused by colon dysfunction. Poly-γ-glutamic acid (γ-PGA), an anionic polymer known for its moisture retention, degradability, and food safety, was studied for its effects on loperamide-induced STC in mice. Treatment with γ-PGA for one week significantly increased both defecation frequency and fecal water content, with the high-dose group (10 g/kg/d) restoring fecal water content to 34.23%, outperforming the low- (16.16%) and medium-dose (27.08%) groups and exceeding the positive control, PEG, by 1.35 times. γ-PGA enhanced intestinal peristalsis and reduced the expression of inflammatory markers (IL-1β, IL-6, caspase-1, TLR2) and water-electrolyte transport genes (AQP3, AQP4, ENaC-β), while improving the expression of tight junction proteins (Claudin-1, Occludin, ZO-1) damaged by loperamide. Histopathological analyses confirmed γ-PGA's capacity to repair intestinal damage. Additionally, Western Blot analysis indicated reduced AQP3/4 levels in the colon, and molecular docking showed good binding affinity between γ-PGA and AQPs. γ-PGA also positively altered gut microbiota composition. Overall, γ-PGA shows promise in treating STC by modulating aquaporins and gut microbiota.

Ligustilide improves functional constipation by non-covalently activating TRPA1 in colon tissue

ETHNOPHARMACOLOGICAL RELEVANCE

Angelica sinensis (Oliv.) Diels (AS), a medicinal plant renowned for its constipation-relieving properties, lacks comprehensive studies on its active pharmaceutical ingredients (APIs) and underlying mechanisms. In the gastrointestinal tract, TRP channels enhance colonic mucus secretion, expedite intestinal motility, and regulate gastrointestinal hormones; however, few reports have systematically established the relationship between TRPs and ligustilide (Lig), a key API of AS.

AIM OF THE STUDY

This study aimed to explore the pharmacodynamic properties of AS in alleviating functional constipation, assess the potential of Lig for activating TRPs, and elucidate its mechanism of action.

METHODS

The therapeutic efficacy of AS was assessed in a mouse model of loperamide hydrochloride-induced functional constipation. The APIs were screened via integrated activity-based UPLC profiling through periodic acid-Schiff (PAS) staining of the colon and immunofluorescence staining of HT-29 cells. The potential target was identified via target fishing and colocalization imaging via an alkynyl-modified Lig probe (AM-Lig). Molecular docking, microscale thermophoresis (MST), fluorescence quenching (FQ), and Fluo-4/Ca2+ influx assays were employed to reveal the interaction mode between Lig and the target protein. Finally, we assessed the efficacy of Lig in alleviating constipation in an animal model.

RESULTS

The efficacy of AS in improving functional constipation was demonstrated in a mouse constipation model, with Lig identified as the primary constituent responsible for inducing colon mucus secretion. Lig specifically targets TRPA1 in the colon, leading to calcium influx and subsequent mucus secretion, ultimately ameliorating functional constipation. Furthermore, a binding mode study revealed that Lig attaches to Thr684, located in the pre-S1 region, triggering TRPA1 channel activation.

CONCLUSIONS

Our findings demonstrate that Lig, the API in AS for constipation treatment, activates TRPA1 through non-covalent interactions, increasing mucus secretion and improving functional constipation. These findings advance our understanding of the therapeutic mechanism of AS and Lig on constipation and suggest a new approach for developing TRPA1 agonists.

Interferential Current Stimulation Enhances Rectal Motor Activity: Insights from an Isolated Perfused Porcine Model

INTRODUCTION

 Interferential current (IFC) has been studied in several clinical trials for the treatment of bowel motility disorders, most often in children. However, only moderate effects are reported, and in contrast to IFC, the so-called placebo application is indiscernible. The mechanisms and neuroanatomic points of action remain elusive. Therefore, this therapy remains being questioned.

METHODS

 To gain objective experimental data about IFC stimulation, we examined this method ex vivo in an isolated perfused porcine rectum including the mesorectum. To elucidate the role of plexus nerve fibers and enteric ganglia, we performed IFC stimulation also in the presence of tetrodotoxin (TTX) or hexamethonium (HXN). We applied the commonly used stimulation modes with a beat frequency sweeping between 5 and 25 Hz (IFCd5-25) and 80 and 150 Hz (IFCd80-150). We monitored intraluminal pressure and motility by online barometry and video recording, respectively. Motor activity, reflected by changes in the intraluminal pressure (cm H2O·s-1) and longitudinal movements (pixels·s-1), was quantified over time as root mean squares (RMSs).

RESULTS

 After IFCd5-25, we observed a 30% increase in the rectal motility in the pressure changes which was sustained over 30 minutes post-stimulation (p < 0.02); only a minor effect was detected for IFCd80-150. Both TTX and HTX abolished the stimulation. This suggests neuronal modulation.

CONCLUSION

 IFCd5-25 stimulates rectal motor activity in the isolated perfused porcine rectum. Ganglia in the enteric nervous system are modulated to allow increased activity for at least 30 minutes. Therefore, the isolated porcine rectum is a suitable tool to study the effectiveness of various IFC settings in the rectum.

Examining linaclotide for the treatment of chronic idiopathic constipation

INTRODUCTION

Chronic idiopathic constipation (CIC) is characterized by infrequent bowel movements and hard stools lasting for at least three months or longer. This disease affects 8-12% of the US population and 10-17% of the world population. Treatment and management involve identifying the primary cause, changing dietary habits, and adequate physical activity. Linaclotide is a guanylate cyclase-agonist acting locally in the luminal surface of the intestinal enterocyte leading to a signal transduction cascade, activation of the cystic fibrosis transmembrane conductance regulator (CFTR), thus increasing secretion of chloride and bicarbonate into the intestinal lumen with eventual increased intestinal fluid and faster transit time.

AREAS COVERED

We reviewed multiple studies and did a thorough literature review on CIC including its pathophysiology. Through this literature review, we were able to discuss and give the context and rationale for drug regimens indicated for CIC.

EXPERT OPINION

The era we live in right now is akin to nutrient-rich and fertilized soil as knowledge and resources are abundant. The opportunities and potential are endless. Constipation being more extensively studied, our understanding of medications and diseases broadens, leading to novel medications being discovered. Linaclotide is a pioneer in this aspect and can pave the way for future generations.

Effects of Liqi Tongbian decoction on gut microbiota, SCFAs production, and 5-HT pathway in STC rats with Qi Stagnation Pattern

Slow transit constipation (STC) is a common and debilitating condition characterized by delayed colonic transit and difficulty in fecal expulsion, significantly impacting patients' physical and mental wellbeing as well as their overall quality of life. This study investigates the therapeutic potential of Liqi Tongbian Decoction (LTD) in the treatment of STC, especially in cases involving the context of Qi stagnation, through a multifaceted approach involving the modulation of intestinal flora and short-chain fatty acids (SCFAs). We employed a rat model of STC with Qi Stagnation Pattern, established using the "loperamide + tail-clamping provocation method," to explore the effects of LTD on fecal characteristics, intestinal motility, and colonic pathology. Importantly, LTD exhibited the ability to increase the richness, diversity, and homogeneity of intestinal flora while also modulating the composition of microorganisms. It significantly increased the production of SCFAs, especially butyric acid. Moreover, LTD exerted a substantial influence on the synthesis of serotonin (5-HT) by modulating the expression of tryptophan hydroxylase (TPH) and interacting with the 5-HT4 receptor (5-HT4R), resulting in enhanced colonic motility. Correlation analyses revealed a positive correlation between certain bacterial genera, such as Lachnospiraceae_NK4A136 spp. and Clostridiales spp. and the concentrations of butyric acid and 5-HT. These results suggest a mechanistic link between microbiome composition, SCFAs production, and 5-HT synthesis. These findings highlight the potential of LTD to alleviate STC by facilitating a beneficial interplay among intestinal flora, SCFAs production, and 5-HT-mediated colonic motility, providing novel insights into the management of STC with Qi Stagnation Pattern.