Reproducibility of assessing fecal microbiota in chronic constipation

Chronic constipation and gut microbiota: current research insights and therapeutic implications

Chronic constipation is a prevalent clinical condition. Its etiology and pathogenesis have not yet been fully understood. In recent years, mounting evidence suggests a close association between chronic constipation and intestinal dysbiosis, including alterations in the colony structure and metabolites, as well as the modulation of bowel movements via the brain-gut-microbiota axis. With the deepening of related research, probiotic-related therapies are expected to become a potential first-line treatment for chronic constipation in the future. In this review, we summarize the current research insights into the intricate relationships between chronic constipation and the gut microbiota and briefly discuss several different approaches for treating chronic constipation. The findings from this review may advance our understanding of the pathological mechanisms underlying chronic constipation and, ultimately, translate them into improvements in patient care.

Gender Influences Gut Microbiota among Patients with Irritable Bowel Syndrome

Irritable bowel syndrome (IBS) is a chronic functional gastrointestinal disease that affects approximately 11% of the general population. The gut microbiota, among other known factors, plays a substantial role in its pathogenesis. The study aimed to characterize the gut microbiota differences between patients with IBS and unaffected individuals, taking into account the gender aspect of the patients and the types of IBS determined on the basis of the Rome IV Criteria, the IBS-C, IBS-D, IBS-M, and IBS-U. In total, 121 patients with IBS and 70 unaffected individuals participated in the study; the derived stool samples were subjected to 16S rRNA amplicon sequencing. The gut microbiota of patients with IBS was found to be more diverse in comparison to unaffected individuals, and the differences were observed primarily among Clostridiales, Mogibacteriaceae, Synergistaceae, Coriobacteriaceae, Blautia spp., and Shuttleworthia spp., depending on the study subgroup and patient gender. There was higher differentiation of females' gut microbiota compared to males, regardless of the disease status. No correlation between the composition of the gut microbiota and the type of IBS was found. Patients with IBS were characterized by more diverse gut microbiota compared to unaffected individuals. The gender criterion should be considered in the characterization of the gut microbiota. The type of IBS did not determine the identified differences in gut microbiota.

Efficacy of Bacillus coagulans BC01 on loperamide hydrochloride-induced constipation model in Kunming mice

In this study, the laxative effect of Bacillus coagulans BC01 (BC01) in mice was investigated using a functional constipation mouse model. Six-week-old male specific pathogen-free (SPF) Kunming mice were randomly divided into five groups: normal control group (saline), model group (loperamide hydrochloride), drug control group (bisacodyl), BC01 low-dose group (4.0 × 10⁸ CFU/mL) and BC01 high-dose group (4.0 × 10⁹ CFU/mL). Except for the normal group, the functional constipation model was established by administering 0.25 mL of a loperamide hydrochloride suspension (1 mg/mL) twice daily for four consecutive days by oral gavage. After modeling, the BC01 groups were administered 0.25 mL of BC01. The bisacodyl served as a control and was administered orally at a dose of 100 mg/kg, while the other groups were administered 0.25 mL of sterile saline. After 7 days of continuous administration, the experimental mice were again induced by loperamide hydrochloride. During this period, the mechanism of BC01 to improve constipation symptoms in mice was analyzed by measuring the changes in body weight, fecal water content, small intestine propulsion rate, histology of small intestinal tissue sections, fecal microbial diversity, serum indices, as well as mRNA and protein expression levels in the small intestinal tissue. BC01 was found to significantly promote the intestinal propulsion rate and increase the fecal water content in the mice. BC01 could also alleviates constipation by regulating gastrointestinal motility (substance P, motilin, endothelin-1, somatostatin, and vasoactive intestinal peptide), gene expression (c-Kit, SCF, COX-2, NF-κB, iNOS, and eNOS), intestinal inflammation (eNOS, iNOS, NF-κB), and the intestinal microbiota composition in the constipated mice. In addition, the high-dose BC01 treatment had the best preventive effect on constipation. BC01 is a probiotic strain to effectively relieve the adverse effects of constipation.

Functional Gastrointestinal Disorders and the Microbiome-What Is the Best Strategy for Moving Microbiome-based Therapies for Functional Gastrointestinal Disorders into the Clinic?

There have been numerous human studies reporting associations between the intestinal microbiome and functional gastrointestinal disorders (FGIDs), and independently animal studies have explored microbiome-driven mechanisms underlying FGIDs. However, there is often a disconnect between human and animal studies, which hampers translation of microbiome findings to the clinic. Changes in the microbiota composition of patients with FGIDs are generally subtle, whereas changes in microbial function, reflected in the fecal metabolome, appear to be more precise indicators of disease subtype-specific mechanisms. Although we have made significant progress in characterizing the microbiome, to effectively translate microbiome science in a timely manner, we need concurrent and iterative longitudinal studies in humans and animals to determine the precise microbial functions that can be targeted to address specific pathophysiological processes in FGIDs. A systems approach integrating multiple data layers rather than evaluating individual data layers of symptoms, physiological changes, or -omics data in isolation will allow for validation of mechanistic insights from animal studies while also allowing new discovery. Patient stratification for clinical trials based on functional microbiome alterations and/or pathophysiological measurements may allow for more accurate determination of efficacy of individual microbiome-targeted interventions designed to correct an underlying abnormality. In this review, we outline current approaches and knowledge, and identify gaps, to provide a potential roadmap for accelerating translation of microbiome science toward microbiome-targeted personalized treatments for FGIDs.

Prevention of loperamide induced constipation in mice by KGM and the mechanisms of different gastrointestinal tract microbiota regulation

Constipation is one of the most prevalent gastrointestinal tract diseases. Konjac glucomannan (KGM) dietotherapy can effectively relieve the clinical symptoms of patients with constipation. However, the causal relationship among KGM, constipation and different gastrointestinal microbiome (i.e., the stomach {St}, small intestine {S}, and large intestine {L}) remains poorly understood. In this study, constipated mice were treated with KGM (75, 150, 300 mg/kg bw). Results showed that KGM treatment improved the general physiological state, fecal character, small intestinal propulsive rate, gastric emptying rate, MTL and AchE activities, ET-1, 5-HT, and NO levels, and SCFA concentrations. KGM in the diets of constipated mice reduced the diversity of St and S microbiota, while increased those in the L. The KGM intervention regulated the microbiota profile, which afterwards was closer to the normal mouse group: confirmation was provided by different changes of bacteria like Lactobacillus, Bifidobacterium and Allobaculum spp et al.

Laxative Effects of Yangyin Tongmi Capsule on a Model of Diphenoxylate-Induced Constipation in Mice

Constipation is characterized by reduced number of bowel movements, dry stools, and difficult defecation. Yangyin Tongmi capsule (YTC), a traditional Chinese formula, is used in the treatment of constipation, while the underlying mechanisms remain unknown. Herein, this work attempted to prove the effects of YTC on constipation treatment and its possible mechanisms. KM mice were randomly divided into four groups (n = 10/group) and treated with double distilled water (Control), diphenoxylate (Model: 10 mg/kg), or diphenoxylate plus low-dose YTC (L-YTC: 0.6 g/kg) or high-dose YTC (H-YTC: 1.2 g/kg). The data indicated that YTC can significantly shorten the discharge time of the first black stool, improve intestinal propulsion rate, and increase the water content and quantity of feces in mice. ELISA suggested that YTC regulate the content of intestinal hormones and neurotransmitters, such as motilin (MTL), gastrin (GT), somatostatin (SST), substance P (SP), acetylcholine (Ach), and nitric oxide (NO). The expression levels of aquaporin 3 (AQP3) and aquaporin 8 (AQP8) in the colon were examined by immunohistochemistry. In the meantime, the expression levels of P2X2, C-kit, and stem cell factor (SCF) in the colon were examined by western blot analysis. The results of this study suggest that YTC has mitigative effects on diphenoxylate-induced constipation by regulating the content of intestinal hormones and neurotransmitters and regulating the expression of related proteins in the colon.

GUT MICROBIOTA AND THE USE OF PROBIOTICS IN CONSTIPATION IN CHILDREN AND ADOLESCENTS: SYSTEMATIC REVIEW

Objective:

To perform a systematic review of literature data on gut microbiota and the efficacy of probiotics for the treatment of constipation in children and adolescents.

Data source:

The research was performed in the PubMed, the Scientific Electronic Library Online (SciELO) and the Latin American and Caribbean Health Sciences Literature (LILACS) databases in English, Portuguese and Spanish. All original articles that mentioned the evaluation of the gut microbiota or the use of probiotics in children with constipation in their title and abstract were selected.

Data synthesis:

559 articles were found, 47 of which were selected for reading. From these, 12 articles were included; they studied children and adolescents divided into two categories: a gut microbiota evaluation (n=4) and an evaluation of the use of probiotics in constipation therapy (n=8). The four papers that analyzed fecal microbiota used different laboratory methodologies. No typical pattern of gut microbiota was found. Regarding treatment, eight clinical trials with heterogeneous methodologies were found. Fifteen strains of probiotics were evaluated and only one was analyzed in more than one article. Irregular beneficial effects of probiotics have been demonstrated in some manifestations of constipation (bowel frequency or consistency of stool or abdominal pain or pain during a bowel movement or flatulence). In one clinical trial, a complete control of constipation without the use of laxatives was obtained.

Conclusions:

There is no specific pattern of fecal microbiota abnormalities in constipation. Despite the probiotics’ positive effects on certain characteristics of the intestinal habitat, there is still no evidence to recommend it in the treatment of constipation in pediatrics.

Establishing a donor stool bank for faecal microbiota transplantation: methods and feasibility

Faecal microbiota transplantation (FMT) is a promising treatment, but donor selection and implementation in clinical practice are difficult. Here, we describe the establishment of a donor stool bank based on the Tissue Act. Stool donors were recruited among blood donors and asked to donate five times in a month. A screening questionnaire, a medical interview and testing of blood and stool were conducted before and after donations. Donations were made at home and transported to the lab, where 50 g of stool was suspended and filtered in saline and 20-mL glycerol (final concentration of 10%) to a volume of 170 mL. The processed stool was assigned a batch number, frozen within 2 h after defecation and stored at - 80 °C for up to 1 year. All steps were documented and cross-checked before donor stool were released for clinical use. Thirteen donors were eligible at the first interview and started donations. Two donors were excluded due to a positive Helicobacter pylori test, two withdrew consent and one was lost to follow-up. One donor took a single dose of NSAIDs 2 days prior to a donation, which was discarded. There were no other excluding findings at the second interview or testing. Eight of the 13 donors were approved as stool donors. All donated five times with each donation yielding 1-6 portions. Eighty-four portions were released for clinical use. Recruiting stool donors among blood donors is safe and effective. The Tissue Act yields an appropriate regulative framework for FMT.

The Gut Microbiome in Adult and Pediatric Functional Gastrointestinal Disorders

The importance of gut microbiota in gastrointestinal (GI) physiology was well described, but our ability to study gut microbial ecosystems in their entirety was limited by culture-based methods prior to the sequencing revolution. The advent of high-throughput sequencing opened new avenues, allowing us to study gut microbial communities as an aggregate, independent of our ability to culture individual microbes. Early studies focused on association of changes in gut microbiota with different disease states, which was necessary to identify a potential role for microbes and generate novel hypotheses. Over the past few years the field has moved beyond associations to better understand the mechanistic implications of the microbiome in the pathophysiology of complex diseases. This movement also has resulted in a shift in our focus toward therapeutic strategies, which rely on better understanding the mediators of gut microbiota-host cross-talk. It is not surprising the gut microbiome has been implicated in the pathogenesis of functional gastrointestinal disorders given its role in modulating physiological processes such as immune development, GI motility and secretion, epithelial barrier integrity, and brain-gut communication. In this review, we focus on the current state of knowledge and future directions in microbiome research as it pertains to functional gastrointestinal disorders. We summarize the factors that help shape the gut microbiome in human beings. We discuss data from animal models and human studies to highlight existing paradigms regarding the mechanisms underlying microbiota-mediated alterations in physiological processes and their relevance in human interventions. While translation of microbiome science is still in its infancy, the outlook is optimistic and we are advancing in the right direction toward precise mechanism-based microbiota therapies.

Non-isoflavones Diet Incurred Metabolic Modifications Induced by Constipation in Rats via Targeting Gut Microbiota

Isoflavones, presenting in leguminous plants and the normal chow diet, are known to alter intestinal microbiota, yet their deficiency has not been widely studied for its effect on constipation in biochemical state of rats. Our previous study discovered the differences in pharmacokinetic traits of isoflavones from Semen sojae praeparatum fed with normal chow diet (ISO) and non-isoflavones diet (NISO). To gain insight into the key role of intestinal microbiota in constipation and metabolic differences caused by isoflavones deficiency, we observed a significant decrease in fecal pellet numbers, fecal water content, intestinal transit rate together with the serum concentrations of substance P (SP) and vasoactive intestinal peptide (VIP) in NISO group, compared with those in the ISO group. Following 16S rRNA compositional sequencing, results excluded the changes in intestinal microbiota over time and highlighted that a total of 5 phyla and 21 genera changed significantly, among which Firmicutes, Bacteroidetes, Blautia, Prevotella, Lactobacillus and Bifidobacterium were closely related to constipation. In addition, Lactobacillus, produceing β-glucosidase which contribute to biotransform glycosides into aglycons and exert the bioactivities consequently, was decreased after non-isoflavones diet intake. Meanwhile, predicted metagenomics indicated that the pathway of glycan biosynthesis and metabolism was markedly down-regulated after non-isoflavones diet intake. Taken together, the findings suggested that the changes in the dietary components could alter the biochemical state of rats, which may be triggered by the abnormal modifications facilitated by β-glucosidase-producing bacteria. Our study shed a new strategy to explore the relationship among disease phenotypes (D), intestinal microbiota (I), enzymes (E) and traits of metabolism (T) named as "DIET," which can provide a reference for further study of the mechanism in regulation of intestinal bacteria-mediated diet on diseases.

Green Tea Liquid Consumption Alters the Human Intestinal and Oral Microbiome

SCOPE

GTPs (green tea polyphenols) exert anti-CRC (colorectal cancer) activity. The intestinal microbiota and intestinal colonization by bacteria of oral origin has been implicated in colorectal carcinogenesis. GT modulates the composition of mouse gut microbiota harmonious with anticancer activity. Therefore, the effect of green tea liquid (GTL) consumption on the gut and oral microbiome is investigated in healthy volunteers (n = 12).

METHODS AND RESULTS

16S sequencing and phylogenetic investigation of communities by reconstruction of unobserved states (PICRUSt) analysis of both fecal and saliva samples (collected before intervention, after 2 weeks of GTL (400 mL per day) and after a washout period of one week) in healthy volunteers show changes in microbial diversity and core microbiota and difference in clear classification (partial least squares-discriminant analysis [PLS-DA]). An irreversible, increased FIR:BAC (Firmicutes to Bacteroidetes ratio), elevated SCFA producing genera, and reduction of bacterial LPS synthesis in feces are discovered in response to GTL. GTL alters the salivary microbiota and reduces the functional pathways abundance relevance to carcinogenesis. Similar bacterial networks in fecal and salivary microbiota datasets comprising putative oral bacteria are found and GTL reduces the fecal levels of Fusobacterium. Interestingly, both Lachnospiraceae and B/E (Bifidobacterium to Enterobacteriacea ratio-markers of colonization resistance [CR]) are negatively associated with the presence of oral-like bacterial networks in the feces.

CONCLUSION

These results suggest that GTL consumption causes both oral and gut microbiome alterations.

Naringenin induces laxative effects by upregulating the expression levels of c-Kit and SCF, as well as those of aquaporin 3 in mice with loperamide-induced constipation

Constipation is a common affliction which causes discomfort and affects the quality of life of affected individuals. Naringenin (NAR), a natural flavonoid widely found in citrus fruits and tomatoes, has been reported to exhibit various pharmacological effects, such as anti-inflammatory, anti-atherogenic, anti-mutagenic, hepatoprotective and anticancer effects. Increasing evidence has indicated that NAR has potential for use in the treatment of constipation. Thus, the aim of this study was to evaluate the laxative effects of NAR in mice with loperamide-induced (Lop-induced) constipation. The data indicated that NAR relieved Lop-induced constipation in mice based on the changes of fecal parameters (numbers, weight and water content), the intestinal charcoal transit ratio and the histological alteration. ELISA revealed that NAR regulated the production levels of gastrointestinal metabolic components, such as motilin (MTL), gastrin (Gas), endothelin (ET), substance P (SP), acetylcholinesterase (AChE) and vasoactive intestinal peptide (VIP) in serum. The expression levels of enteric nerve-related factors, glial cell line-derived neurotrophic factor (GDNF), transient receptor potential vanilloid 1 (TRPV1), nitric oxide synthase (NOS), c-Kit, stem cell factor (SCF) and aquaporin 3 (AQP3) were examined by western blot analysis and RT-PCR analysis. The results of this study suggest that NAR relieves Lop-induced constipation by increasing the levels of interstitial cells of Cajal markers (c-Kit and SCF), as well as AQP3. Thus, NAR may be effective as a candidate in patients suffering from lifestyle-induced constipation.

Role of microbiota in the pathogenesis of functional disorders of the lower GI tract: Work in progress

Functional bowel disorders affect a significant proportion of people word wide. Patients suffer from longstanding symptoms of abdominal pain or discomfort in combination with abnormal bowel habits. The evidence for role of microbiota is currently contradictory and descriptive. This review aims to summarize the reasons which include methodological differences in DNA extraction and sample handling along with other factors such as diet, prior antibiotic use and transit, all important major determinants of microbiota which are difficult to control. Randomized studies of specific intervention in which such factors are varied may improve reproducibility and consistency of findings in future research.