Comparison of subjective classification of stool consistency and stool water content

Species-level quantification of Faecalibacterium spp. in faeces of healthy Japanese adults

Faecalibacterium prausnitzii has been considered one of the predominant microbes in the gut microbiota of healthy human adults. Moreover, due to its beneficial metabolites and its reduced population in patients with various disorders, this organism has been regarded as one of the key gut microbes in human health. However, following recent revisions in the taxonomy of the genus Faecalibacterium and F. prausnitzii, the reported population distribution and health benefits of this species have become unclear. In the present study, the population of nine species-level taxonomic groups (hereafter referred to as species) within Faecalibacterium was quantified at the species level in the faeces of healthy Japanese adults (n=88). qPCR, combined with rpoA-based species-specific primers, showed that Faecalibacterium taiwanense had the highest detection rate (prevalence) and copy number among Faecalibacterium spp., followed by Faecalibacterium longum, Faecalibacterium duncaniae and F. prausnitzii, while the remaining five species were detected only occasionally. The population of F. duncaniae varied significantly between age groups, being higher in individuals in their 40s and 50s compared to those in their 20s (P=0.047 and 0.002, respectively). The present study indicates that F. prausnitzii is not the predominant Faecalibacterium species in the healthy Japanese adults included in the present study. Future studies will shed light on the health benefits of the dominant Faecalibacterium spp.

Precision Dietary Intervention: Gut Microbiome and Meta-metabolome as Functional Readouts

Gut microbiome, the group of commensals residing within the intestinal tract, is closely associated with dietary patterns by interacting with food components. The gut microbiome is modifiable by the diet, and in turn, it utilizes the undigested food components as substrates and generates a group of small molecule-metabolites that addressed as "meta-metabolome" in this review. Profiling and mapping of meta-metabolome could yield insightful information at higher resolution and serve as functional readouts for precision nutrition and formation of personalized dietary strategies. For assessing the meta-metabolome, sample preparation is important, and it should aim for retrieval of gut microbial metabolites as intact as possible. The meta-metabolome can be investigated via untargeted and targeted meta-metabolomics with analytical platforms such as nuclear magnetic resonance spectroscopy and mass spectrometry. Employing flux analysis with meta-metabolomics using available database could further elucidate metabolic pathways that lead to biomarker discovery. In conclusion, integration of gut microbiome and meta-metabolomics is a promising supplementary approach to tailor precision dietary intervention. In this review, relationships among diet, gut microbiome, and meta-metabolome are elucidated, with an emphasis on recent advances in alternative analysis techniques proposed for nutritional research. We hope that this review will provide information for establishing pipelines complementary to traditional approaches for achieving precision dietary intervention.

Assessing hard and loose "endpoints": comparison of patient and expert Bristol Stool Scale scoring of 2280 fecal samples

Background

Stool consistency is an important outcome measure to evaluate in the investigation of several gastrointestinal diseases. The Bristol Stool Scale (BSS) is one of the most commonly used tools for evaluation of stool consistency. BSS ranges from 1-7 and each score is assigned to a given consistency of the feces. Self-reported characterizations can differ from an expert evaluation, and the reliability of BSS is unclear. We aimed to evaluate the reliability of BSS by comparing patient scores with expert scores.

Methods

Patients with inflammatory bowel disease collected stool samples throughout a 3-year follow-up. The stool´s consistency was evaluated with BSS by the patients and matched with an expert score. Agreement between patient and expert scores was assessed using Cohen's kappa.

Results

BSS scores from 2280 fecal samples collected from 992 patients at up to five time points were included. When all samples were compared, there was good to substantial agreement between patient and expert scores (Cohen's weighted kappa: 0.66-0.72). When the BSS scores were simplified and categorized as 1 (scores 1-2), 2 (scores 3-5) or 3 (scores 6-7), the agreement improved slightly (Cohen's weighted kappa: 0.73-0.77). When the scores from the first sample per patient were compared, the experts were more likely to assign higher scores compared to the patient. The proportion of the lowest assigned scores (1-2) was 12.1% for patients and 8.1% for experts.

Conclusions

The agreement between patient and expert BSS scores is good to substantial, especially when the BSS scores are simplified into three categories.

Optimization of fecal sample homogenization for untargeted metabolomics

INTRODUCTION

Fecal samples are highly complex and heterogeneous, containing materials at various stages of digestion. The heterogeneity and complexity of feces make stool metabolomics inherently challenging. The level of homogenization influences the outcome of the study, affecting the metabolite profiles and reproducibility; however, there is no consensus on how fecal samples should be prepared to overcome the topographical discrepancy and obtain data representative of the stool as a whole.

OBJECTIVES

Various combinations of homogenization conditions were compared to investigate the effects of bead size, addition of solvents and the differences between wet-frozen and lyophilized feces.

METHODS

The homogenization parameters were systematically altered to evaluate the solvent usage, bead size, and whether lyophilization is required in homogenization. The metabolic coverage and reproducibility were compared among the different conditions.

RESULTS

The current work revealed that a combination of mechanical and chemical lysis obtained by bead-beating with a mixture of big and small sizes of beads in an organic solvent is an effective way to homogenize fecal samples with adequate reproducibility and metabolic coverage. Lyophilization is required when bead-beating is not available.

CONCLUSIONS

A comprehensive and systematical evaluation of various fecal matter homogenization conditions provides a profound understanding for the effects of different homogenization methods. Our findings would be beneficial to assist with standardization of fecal sample homogenization protocol.

Multi-Omics Analysis to Generate Hypotheses for Mild Health Problems in Monkeys

Certain symptoms associated with mild sickness and lethargy have not been categorized as definitive diseases. Confirming such symptoms in captive monkeys (Macaca fascicularis, known as cynomolgus monkeys) can be difficult; however, it is possible to observe and analyze their feces. In this study, we investigated the relationship between stool state and various omics data by considering objective and quantitative values of stool water content as a phenotype for analysis. By examining the food intake of the monkeys and assessing their stool, urine, and plasma, we attempted to obtain a comprehensive understanding of the health status of individual monkeys and correlate it with the stool condition. Our metabolomics data strongly suggested that many lipid-related metabolites were correlated with the stool water content. The lipidomic analysis revealed the involvement of saturated and oxidized fatty acids, metallomics revealed the contribution of selenium (a bio-essential trace element), and intestinal microbiota analysis revealed the association of several bacterial species with the stool water content. Based on our results, we hypothesize that the redox imbalance causes minor health problems. However, it is not possible to make a definite conclusion using multi-omics alone, and other hypotheses could be proposed.

A Low-FODMAP Diet Improves the Global Symptoms and Bowel Habits of Adult IBS Patients: A Systematic Review and Meta-Analysis

Background: A low-fermentable oligo-, di-, monosaccharides, and polyols (FODMAP) diet has been reported to be associated with improving the symptoms of irritable bowel syndrome (IBS); however, its efficacy as evaluated by different studies remains controversial. Objective: A systematic review and meta-analysis of randomized controlled trials (RCTs) were conducted to explore the efficacy of a low-FODMAP diet (LFD) in alleviating the symptoms of IBS. Methods: A search of the literature for RCTs that assessed the efficacy of an LFD in treating IBS patients was conducted using the electronic databases PubMed, Embase, Cochrane Central Register of Controlled Trials, and Web of Science. The searches in each database were conducted from the inception of the database to February 2021. Two independent reviewers screened citations and a third reviewer resolved disagreements. Two independent reviewers also performed eligibility assessments and data extraction. The RCTs that evaluated LFDs vs. a normal IBS or usual diet and assessed changes of IBS symptoms were included in the search. Data were synthesized as the relative risk of global symptoms improvement, mean difference of IBS Severity Scoring System (IBS-SSS) score, sub-items of IBS-SSS irritable bowel syndrome-related quality of life (IBS-QOL), hospital anxiety and depression scale (HADS), stool consistency/frequency, and body mass index (BMI) using a random effects model. The risk of bias was assessed using Risk of Bias Tool 2 (RoB 2). The bias of publication was assessed based on Egger's regression analysis. The quality of evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) methodology. Results: A total of 2,768 citations were identified. After full-text screening, a total of 10 studies were eligible for the systematic review and were subsequently used to compare an LFD with various control interventions in 511 participants. An LFD was associated with the improvement of global symptoms [n = 420; Risk Ratio (RR) = 1.54; 95% Confidence Interval (CI) 1.18 to 2; I 2 = 38%], improvement of stool consistency [n = 434; Mean difference (MD) = -0.25; 95% CI -0.44 to -0.06; I 2= 19%), and a reduction trend of stool frequency (n = 434; MD = -0.28; 95% CI -0.57 to 0.01; I 2 = 68%) compared with control interventions. There was no statistically significant change in IBS-QOL (n = 484; MD = 2.77; 95% CI -2 to 7.55; I 2 = 62%), anxiety score (n = 150; MD = -0.45; 95% CI -3.38 to 2.49; I 2 = 86%), depression score (n = 150; MD = -0.05; 95% CI -2.5 to 2.4; I 2 = 88%), and BMI (n = 110; MD = -0.22; 95% CI -1.89 to 1.45; I 2 = 14%). The overall quality of the data was "moderate" for "global improvement of IBS symptom," "stool consistency," "stool consistency for IBS with diarrhea (IBS-D)," and "stool frequency for IBS-D," and "low" or "very low" for other outcomes according to GRADE criteria. Conclusion: An LFD is effective in reducing the global symptoms and improving the bowel habits of adult IBS patients. The efficacy for IBS-D patients can also be more pronounced. Systematic Review Registration: CRD42021235843.

Discrepancy between self-perceived mycophenolic acid-associated diarrhea and stool water content after kidney transplantation

BACKGROUND

Diarrhea is a well-known side effect of mycophenolic acid (MPA) use in kidney transplant recipients (KTRs). It is unknown whether self-reported diarrhea using the Modified Transplant Symptom Occurrence and Symptom Distress Scale (MTSOSD-59R) corresponds to stool water content and how both relate to MPA usage.

METHODS

MTSOSD-59R questionnaires filled out by 700 KTRs from the TransplantLines Biobank and Cohort Study (NCT03272841) were analyzed and compared with stool water content. Stool samples (N = 345) were freeze-dried, and a water content ≥80% was considered diarrhea.

RESULTS

Self-perceived diarrhea was reported by 46%, while stool water content ≥80% was present in 23% of KTRs. MPA use was not associated with self-perceived diarrhea (odds ratio(OR) 1.32; 95% confidence interval(CI), 0.87-1.99, p = .2), while it was associated with stool water content ≥80% (OR 2.88; 95%CI, 1.41-5.89, p = .004), independent of potential confounders. Adjustment for prior MPA discontinuation because of severe diarrhea, uncovered an association between MPA use and self-perceived diarrhea (OR 1.80; 95%CI, 1.13-2.89, p = .01).

CONCLUSIONS

These results suggest that reporting bias could add to the discrepancy between both methods for diarrhea assessment. We recommend use of objective biomarkers or more extensive questionnaires which assess information on stool frequency and stool consistency, to investigate post-transplantation diarrhea.

The Application of Metabolomics to Probiotic and Prebiotic Interventions in Human Clinical Studies

There is an ever-increasing appreciation for our gut microbiota that plays a crucial role in the maintenance of health, as well as the development of disease. Probiotics are live bacteria that are consumed to increase the population of beneficial bacteria and prebiotics are dietary substrates intended to promote the propagation of beneficial bacteria. In order to optimize the use of probiotics and prebiotics, a more complete biochemical understanding of the impact that these treatments have on the community and functioning of the gut microbiota is required. Nucleic acid sequencing methods can provide highly detailed information on the composition of the microbial communities but provide less information on the actual function. As bacteria impart much of their influence on the host through the production of metabolites, there is much to be learned by the application of metabolomics. The focus of this review is on the use of metabolomics in the study of probiotic and prebiotic treatments in the context of human clinical trials. Assessment of the current state of this research will help guide the design of future studies to further elucidate the biochemical mechanism by which probiotics and prebiotics function and pave the way toward more personalized applications.

Microbiota Analysis Using Two-step PCR and Next-generation 16S rRNA Gene Sequencing

The human gut is colonized by trillions of bacteria that support physiologic functions such as food metabolism, energy harvesting, and regulation of the immune system. Perturbation of the healthy gut microbiome has been suggested to play a role in the development of inflammatory diseases, including multiple sclerosis (MS). Environmental and genetic factors can influence the composition of the microbiome; therefore, identification of microbial communities linked with a disease phenotype has become the first step towards defining the microbiome's role in health and disease. Use of 16S rRNA metagenomic sequencing for profiling bacterial community has helped in advancing microbiome research. Despite its wide use, there is no uniform protocol for 16S rRNA-based taxonomic profiling analysis. Another limitation is the low resolution of taxonomic assignment due to technical difficulties such as smaller sequencing reads, as well as use of only forward (R1) reads in the final analysis due to low quality of reverse (R2) reads. There is need for a simplified method with high resolution to characterize bacterial diversity in a given biospecimen. Advancements in sequencing technology with the ability to sequence longer reads at high resolution have helped to overcome some of these challenges. Present sequencing technology combined with a publicly available metagenomic analysis pipeline such as R-based Divisive Amplicon Denoising Algorithm-2 (DADA2) has helped advance microbial profiling at high resolution, as DADA2 can assign sequence at the genus and species levels. Described here is a guide for performing bacterial profiling using two-step amplification of the V3-V4 region of the 16S rRNA gene, followed by analysis using freely available analysis tools (i.e., DADA2, Phyloseq, and METAGENassist). It is believed that this simple and complete workflow will serve as an excellent tool for researchers interested in performing microbiome profiling studies.

An MRI-guided HIFU-triggered wax-coated capsule for supertargeted drug release: a proof-of-concept study

BACKGROUND

Externally controlling and monitoring drug release at a desired time and location is currently lacking in the gastrointestinal tract. The aim of the study was to develop a thermoresponsive wax-coated capsule and to trigger its release upon applying a magnetic resonance imaging (MRI)-guided high-intensity focused ultrasound (HIFU) pulse.

METHODS

Capsules containing a lyophilised gadolinium-based contrast agent (GBCA) were coated with a 1:1 (mass/mass) mixture of lanolin and cetyl alcohol (melting point ≈43 °C) and exposed to simulated gastric and intestinal fluids (United States Pharmacopoeia) at 37 °C for 2 and 24 h, respectively. In a HIFU gel phantom, wax-coated capsules (n = 3) were tracked based on their T1- and T2-hypointensity by 1.5-T T1- and T2-weighted MRI pre- and post-exposure to an MRI-guided HIFU pulse.

RESULTS

Lanolin/cetyl alcohol-coated capsules showed high resistance to simulated gastrointestinal fluids. In a gel phantom, an MRI-guided HIFU pulse punctured the wax coating, resulting in the hydration and release of the encapsulated lyophilised GBCA and yielding a T1-hyperintense signal close to the wax-coated capsule.

CONCLUSION

We provide the proof-of-concept of applying a non-invasive MRI-guided HIFU pulse to actively induce the disintegration of the wax-coated capsule, and a method to monitor the release of the cargo via T1-weighted MRI based on the hydration of an encapsulated lyophilised GBCA. The wax-coated capsule platform enables temporally and spatially supertargeted drug release via the oral route and promises to address a currently unmet clinical need for personalised local therapy in gastrointestinal diseases such as inflammatory bowel diseases and cancer.

Incidence and Characteristics of Incontinence-Associated Dermatitis in Community-Dwelling Persons With Fecal Incontinence

PURPOSE

Little is known about the incidence and characteristics of incontinence-associated dermatitis (IAD) in community-living individuals with fecal incontinence. The primary aim of this study was to describe the incidence and characteristics of self-reported IAD among community-living individuals with fecal incontinence. The study also examined whether IAD was associated with older age, sex, presence of urinary incontinence, or fecal incontinence severity.

DESIGN

Secondary data analysis was performed using a prospective cohort design.

SUBJECTS AND SETTING

Data were drawn from community-living adults (n = 98) with fecal incontinence (76% female, 34% aged ≥65 years, 90% white) who participated in a study about dietary fiber supplementation and were free of IAD at the start. Thirty five percent also had urinary incontinence.

METHODS

Subjects assessed their skin for IAD daily for 52 days, reporting types of IAD damage (redness, rash/fungal infection, and skin loss), location of IAD, and symptoms. They reported fecal incontinence on a diary for the first and last 14 study days.

RESULTS

The incidence of IAD was 41% (40 of the 98). The fecal incontinence severity score for subjects developing IAD was 1.2 higher than those who never had IAD (P < .001). There was no significant association of IAD with age, sex, or dual fecal and urinary incontinence. Incontinence-associated dermatitis developed within 2 weeks and healed in approximately 1 week. The most common sign and symptom were redness (60% patients) and soreness (78% patients), respectively. Most subjects (85%) had IAD in one location.

CONCLUSIONS

Assessing for IAD in community-living patients with fecal incontinence is important as IAD is common and causes discomfort. The relatively mild severity of IAD offers WOC nurses the opportunity for improving patient outcomes by preventing and managing this problem.

Ecophysiological consequences of alcoholism on human gut microbiota: implications for ethanol-related pathogenesis of colon cancer

Chronic consumption of excess ethanol increases the risk of colorectal cancer. The pathogenesis of ethanol-related colorectal cancer (ER-CRC) is thought to be partly mediated by gut microbes. Specifically, bacteria in the colon and rectum convert ethanol to acetaldehyde (AcH), which is carcinogenic. However, the effects of chronic ethanol consumption on the human gut microbiome are poorly understood, and the role of gut microbes in the proposed AcH-mediated pathogenesis of ER-CRC remains to be elaborated. Here we analyse and compare the gut microbiota structures of non-alcoholics and alcoholics. The gut microbiotas of alcoholics were diminished in dominant obligate anaerobes (e.g., Bacteroides and Ruminococcus) and enriched in Streptococcus and other minor species. This alteration might be exacerbated by habitual smoking. These observations could at least partly be explained by the susceptibility of obligate anaerobes to reactive oxygen species, which are increased by chronic exposure of the gut mucosa to ethanol. The AcH productivity from ethanol was much lower in the faeces of alcoholic patients than in faeces of non-alcoholic subjects. The faecal phenotype of the alcoholics could be rationalised based on their gut microbiota structures and the ability of gut bacteria to accumulate AcH from ethanol.

Dietary fiber supplementation for fecal incontinence: a randomized clinical trial

Dietary fiber supplements are used to manage fecal incontinence (FI), but little is known about the fiber type to recommend or the level of effectiveness of such supplements, which appears related to the fermentability of the fiber. The aim of this single-blind, randomized controlled trial was to compare the effects of three dietary fiber supplements (carboxymethylcellulose [CMC], gum arabic [GA], or psyllium) with differing levels of fermentability to a placebo in community-living individuals incontinent of loose/liquid feces. The primary outcome was FI frequency; secondary outcomes included FI amount and consistency, supplement intolerance, and quality of life (QoL). Possible mechanisms underlying supplement effects were also examined. After a 14-day baseline, 189 subjects consumed a placebo or 16 g total fiber/day of one of the fiber supplements for 32 days. FI frequency significantly decreased after psyllium supplementation versus placebo, in both intent-to-treat and per-protocol mixed model analyses. CMC increased FI frequency. In intent-to-treat analysis, the number of FI episodes/week after supplementation was estimated to be 5.5 for Placebo, 2.5 for Psyllium, 4.3 for GA, and 6.2 for CMC. Only psyllium consumption resulted in a gel in feces. Supplement intolerance was low. QoL scores did not differ among groups. Patients with FI may experience a reduction in FI frequency after psyllium supplementation, and decreased FI frequency has been shown to be an important personal goal of treatment for patients with FI. Formation of a gel in feces appears to be a mechanism by which residual psyllium improved FI.