Faecal Microbiota in Patients with Neurogenic Bowel Dysfunction and Spinal Cord Injury or Multiple Sclerosis-A Systematic Review

Influence of Dietary Quality on Neurogenic Bowel Dysfunction in Individuals With Spinal Cord Injury

Background

Neurogenic bowel dysfunction (NBD) occurs in up to 95% of individuals with spinal cord injury (SCI) and negatively impacts the quality of life. Although diet is an important component in the management of NBD, the relationship between diet quality and NBD is understudied in the SCI population.

Objectives

To assess the diet quality of individuals with chronic SCI and explore possible relationships between diet quality, especially fiber, and symptoms of NBD, and to evaluate whether individuals with SCI themselves recognize relationships between dietary intake and NBD symptoms.

Methods

Individuals with chronic SCI, recruited via their rehabilitation center, completed web-based questionnaires and 24-hour dietary recalls regarding the quality and intake of their diet and the severity of NBD. Ten individuals participated in interviews to explore their views on potential relationships between their diet and NBD.

Results

Twenty-eight participants were recruited, of which ten were interviewed. All participants had symptoms of NBD of varying degrees and a low diet quality, but there was no difference between the NBD groups. The more severe NBD group had a lower intake of vegetables and a higher intake of salt. Almost half of the participants interviewed did not report experiencing an association between dietary intake and their NBD.

Conclusions

A low diet quality was observed among individuals with chronic SCI, irrespective of their NBD symptoms. Many participants were unaware of a potential relationship between their diet and NBD. The sample size is insufficient to draw definitive conclusions; however, a potential hypothesis is that those with more severe NBD may consume not enough vegetables and too much salt. Further longitudinal prospective research is required to enhance nutritional guidelines for individuals with SCI and NBD.

Association of Mucin-Degrading Gut Microbiota and Dietary Patterns with Colonic Transit Time in Constipation: A Secondary Analysis of a Randomized Clinical Trial

BACKGROUND

The relationship between gut microbiota composition, lifestyles, and colonic transit time (CTT) remains poorly understood. This study investigated associations among gut microbiota profiles, diet, lifestyles, and CTT in individuals with subjective constipation.

METHODS

We conducted a secondary analysis of data from our randomized clinical trial, examining gut microbiota composition, CTT, and dietary intake in baseline and final assessments of 94 participants with subjective constipation. Participants were categorized into normal-transit (<36 h) and slow-transit (≥36 h) groups based on CTT at baseline. Gut microbiota composition was measured using 16S rRNA sequencing, and dietary patterns were assessed through semi-quantitative food frequency questionnaires. Enterotype analysis, machine learning approaches, and metabolic modeling were employed to investigate microbiota-diet interactions. The constipated participants primarily belonged to Lachnospiraceae (ET-L).

RESULTS

The slow-transit group showed higher alpha diversity than the normal-transit group. Butyricicoccus faecihominis was abundant in the normal-transit group, while Neglectibacter timonensis, Intestinimonas massiliensis, and Intestinibacter bartlettii were abundant in the slow-transit group, which also had a higher abundance of mucin-degrading bacteria. Metabolic modeling predicted increased N-acetyl-D-glucosamine (GlcNAc), a mucin-derived metabolite, in the slow-transit group. Network analysis identified two microbial co-abundance groups (CAG3 and CAG9) significantly associated with transit time and dietary patterns. Six mucin-degrading species showed differential correlations with GlcNAc and a plant-based diet, particularly, including rice, bread, fruits and vegetables, and fermented beans. In conclusion, an increased abundance of mucin-degrading bacteria and their predicted metabolic products were associated with delayed CTT.

CONCLUSION

These findings suggest dietary modulation of these bacterial populations as a potential therapeutic strategy for constipation. Moreover, our results reveal a potential immunometabolic mechanism where mucin-degrading bacteria and their metabolic interactions may influence intestinal transit, mucosal barrier function, and immune response.

Changes in Gut Microbiota in Patients with Multiple Sclerosis Based on 16s rRNA Gene Sequencing Technology: A Review and Meta-Analysis

BACKGROUND

This meta-analysis explores alterations in the gut microbiota of patients with Multiple Sclerosis (MS) using 16S ribosomal RNA (rRNA) gene sequencing.

METHODS

Adhering to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, our comprehensive review spanned major databases, including PubMed, Web of Science, Embase, Cochrane, and Ovid, targeting observational studies that implemented 16S rRNA gene sequencing on fecal specimens. The quality of these studies was meticulously evaluated using the Newcastle-Ottawa scale.

RESULTS

Our search yielded 26 relevant studies conducted between 2015-2022, encompassing 2885 participants. No significant differences were observed in alpha diversity indices (Shannon, Chao1, Operational Taxonomic Units (OTU), and Simpson) between MS patients and controls in general. Nonetheless, subgroup analyses according to disease activity using the Shannon index highlighted a significant decrease in microbial diversity during MS's active phase. Similarly, an evaluation focusing on MS phenotype revealed diminished diversity in individuals with relapsing-remitting MS (RRMS). Microbial composition analysis revealed no consistent increase in pro-inflammatory Bacteroidetes or decrease in anti-inflammatory Firmicutes within the MS cohort.

CONCLUSION

The gut microbiome's role in MS presents a complex panorama, where alterations in microbial composition might hold greater significance to disease mechanisms than diversity changes. The impact of clinical factors such as disease activity and phenotype are moderately significant, underscoring the need for further research to elucidate these relationships. Prospective research should employ longitudinal methodologies to elucidate the chronological interplay among gut microbiota, disease evolution, and therapeutic strategies.

Bacillus siamensis Improves the Immune Status and Intestinal Health of Weaned Piglets by Improving Their Intestinal Microbiota

Previous studies on the early interference of gut microbiota by Bacillus siamensis (B. siamensis) in weaned piglets are rarely reported, and the present trial is a preliminary study. This experiment was conducted to investigate the effects of B. siamensis supplementation on the growth performance, serum biochemistry, immune response, fecal short-chain fatty acids and microbiota of weaned piglets. Sixty weaned piglets were randomly divided into a control group (CON) and a B. siamensis group (BS), which were fed a basal diet and the basal diet supplemented with 5 × 1010 CFU B. siamensis per kg, respectively. Each group had 3 replicates and 10 piglets per replicate. The trial lasted for 28 days. The results showed that B. siamensis significantly increased the serum growth hormone (GH) and insulin-like growth factor (IGF) in piglets. Compared with the CON group, the levels of serum immunoglobulin and inflammatory factors in the BS group were significantly improved. In addition, the serum concentrations of zonulin and endotoxin (ET) in the BS group were lower. The dietary addition of B. siamensis significantly increased fecal short-chain fatty acid (SCFA) levels in piglets. Notably, B. siamensis improved the microbial composition by increasing beneficial genera, including Weissella, Lachnospiraceae_NK4A136_group and Bifidobacterium, and decreasing pathogenic genera, including Pantoea, Fusobacterium and Gemella, in piglet feces. Correlation analysis showed that the benefits of dietary B. siamensis supplementation were closely related to its improved microbial composition. In summary, the addition of B. siamensis can improve the immunity function, inflammatory response, gut permeability and SCFA levels of weaned piglets, which may be achieved through the improvement of their microbiota.

Dual-directional regulation of spinal cord injury and the gut microbiota

There is increasing evidence that the gut microbiota affects the incidence and progression of central nervous system diseases via the brain-gut axis. The spinal cord is a vital important part of the central nervous system; however, the underlying association between spinal cord injury and gut interactions remains unknown. Recent studies suggest that patients with spinal cord injury frequently experience intestinal dysfunction and gut dysbiosis. Alterations in the gut microbiota can cause disruption in the intestinal barrier and trigger neurogenic inflammatory responses which may impede recovery after spinal cord injury. This review summarizes existing clinical and basic research on the relationship between the gut microbiota and spinal cord injury. Our research identified three key points. First, the gut microbiota in patients with spinal cord injury presents a key characteristic and gut dysbiosis may profoundly influence multiple organs and systems in patients with spinal cord injury. Second, following spinal cord injury, weakened intestinal peristalsis, prolonged intestinal transport time, and immune dysfunction of the intestine caused by abnormal autonomic nerve function, as well as frequent antibiotic treatment, may induce gut dysbiosis. Third, the gut microbiota and associated metabolites may act on central neurons and affect recovery after spinal cord injury; cytokines and the Toll-like receptor ligand pathways have been identified as crucial mechanisms in the communication between the gut microbiota and central nervous system. Fecal microbiota transplantation, probiotics, dietary interventions, and other therapies have been shown to serve a neuroprotective role in spinal cord injury by modulating the gut microbiota. Therapies targeting the gut microbiota or associated metabolites are a promising approach to promote functional recovery and improve the complications of spinal cord injury.

Gut microbiota changes in animal models of spinal cord injury: a preclinical systematic review and meta-analysis

BACKGROUND

An increasing number of studies show that the intestinal flora is closely related to spinal cord injury. Many researchers are exploring the changes in the richness, diversity, and evenness of intestinal flora in spinal cord injury animal models to identify the characteristic bacteria.

METHODS

A comprehensive literature search was conducted using three databases: PubMed, Embase, and Web of Science. A meta-analysis was performed using R 4.3.1 to evaluate the comparison of microbiota diversity, richness, and evenness and the relative abundance of intestinal microbiota in animals with spinal cord injury and blank controls.

RESULTS

Fifteen studies were included in the meta-analysis, of which 12 involved gut microbiota distribution indicators and 11 included intestinal microflora relative abundance indicators. Meta-analysis of high-dimensional indicators describing the distribution of the gut microbiota identified a substantial decline in the evenness and richness of the intestinal flora. In addition, the Actinobacteria phylum and Erysipelotrichales and Clostridiales orders were significantly different between the spinal cord injury and sham groups; therefore, they may be the characteristic bacteria in spinal cord injury models.

CONCLUSION

Our meta-analysis suggested that the gut microbiota in the spinal cord injury animal model group was altered compared with that in the control group, with varying degrees of changes in richness and evenness and potentially pathogenic characteristic flora. More rigorous methodological studies are needed because of the high heterogeneity and limited sample size. Further research is needed to clinically apply intestinal microbiota and potentially guide fecal microbiota transplantation therapy.

Effective bowel management in spinal cord injury during inpatient rehabilitation: data from the Dutch spinal cord injury database

STUDY DESIGN

Retrospective Observational Study.

OBJECTIVES

To describe bowel management in individuals with a recently acquired spinal cord injury (SCI) both at admittance and discharge from first inpatient rehabilitation, and to determine factors that contribute to effective bowel management (EBM) at discharge.

SETTING

Specialized rehabilitation centers in the Netherlands.

METHODS

Data from the Dutch Spinal Cord Injury Database (DSCID) collected between 2015 and 2019 was used. EBM was defined by the variables of stool frequency and fecal incontinence. After univariate analysis, a multivariate regression analysis was conducted.

RESULTS

Of 1,210 participants, 818 (68%) did not have EBM at admittance. At discharge, 308 (38%) did still not have EBM (in total 33% of all participants). The odds of having EBM at discharge was 2.82 times higher for participants with ASIA Impairment Scale (AIS) D compared to those with AIS-A (95% CI: 1.38-5.78). Participants with non-traumatic SCI had higher odds of having EBM than those with traumatic SCI (OR: 0.59, 95% CI 0.38-0.91). Use of suppositories, small enema, medication influencing bowel function, and oral laxatives at admittance did not influence EBM significantly at discharge.

CONCLUSIONS

Bowel management improves during first inpatient rehabilitation. However, realizing EBM after a recently acquired SCI is a challenge. This endorses the importance of bowel management during inpatient rehabilitation, especially for people with AIS-A and non-traumatic etiology.

A comprehensive look at the psychoneuroimmunoendocrinology of spinal cord injury and its progression: mechanisms and clinical opportunities

Spinal cord injury (SCI) is a devastating and disabling medical condition generally caused by a traumatic event (primary injury). This initial trauma is accompanied by a set of biological mechanisms directed to ameliorate neural damage but also exacerbate initial damage (secondary injury). The alterations that occur in the spinal cord have not only local but also systemic consequences and virtually all organs and tissues of the body incur important changes after SCI, explaining the progression and detrimental consequences related to this condition. Psychoneuroimmunoendocrinology (PNIE) is a growing area of research aiming to integrate and explore the interactions among the different systems that compose the human organism, considering the mind and the body as a whole. The initial traumatic event and the consequent neurological disruption trigger immune, endocrine, and multisystem dysfunction, which in turn affect the patient's psyche and well-being. In the present review, we will explore the most important local and systemic consequences of SCI from a PNIE perspective, defining the changes occurring in each system and how all these mechanisms are interconnected. Finally, potential clinical approaches derived from this knowledge will also be collectively presented with the aim to develop integrative therapies to maximize the clinical management of these patients.

Changes in Gut Microbiota and Multiple Sclerosis: A Systematic Review

INTRODUCTION

Multiple sclerosis (MS) is a chronic inflammatory neurodegenerative disease mediated by autoimmune reactions against myelin proteins and gangliosides in the grey and white matter of the brain and spinal cord. It is considered one of the most common neurological diseases of non-traumatic origin in young people, especially in women. Recent studies point to a possible association between MS and gut microbiota. Intestinal dysbiosis has been observed, as well as an alteration of short-chain fatty acid-producing bacteria, although clinical data remain scarce and inconclusive.

OBJECTIVE

To conduct a systematic review on the relationship between gut microbiota and multiple sclerosis.

METHOD

The systematic review was conducted in the first quarter of 2022. The articles included were selected and compiled from different electronic databases: PubMed, Scopus, ScienceDirect, Proquest, Cochrane, and CINAHL. The keywords used in the search were: "multiple sclerosis", "gut microbiota", and "microbiome".

RESULTS

12 articles were selected for the systematic review. Among the studies that analysed alpha and beta diversity, only three found significant differences with respect to the control. In terms of taxonomy, the data are contradictory, but confirm an alteration of the microbiota marked by a decrease in Firmicutes, Lachnospiraceae, Bifidobacterium, Roseburia, Coprococcus, Butyricicoccus, Lachnospira, Dorea, Faecalibacterium, and Prevotella and an increase in Bacteroidetes, Akkermansia, Blautia, and Ruminocococcus. As for short-chain fatty acids, in general, a decrease in short-chain fatty acids, in particular butyrate, was observed.

CONCLUSIONS

Gut microbiota dysbiosis was found in multiple sclerosis patients compared to controls. Most of the altered bacteria are short-chain fatty acid (SCFA)-producing, which could explain the chronic inflammation that characterises this disease. Therefore, future studies should consider the characterisation and manipulation of the multiple sclerosis-associated microbiome as a focus of both diagnostic and therapeutic strategies.

The Role of Gut Microbiota in Various Neurological and Psychiatric Disorders-An Evidence Mapping Based on Quantified Evidence

Methods

We searched PubMed, Cochrane Library, and Epistemonikos to identify systematic reviews and meta-analysis (SRs). We searched for neurological diseases and psychiatric disorders, including Alzheimer's disease (AD), attention deficit hyperactivity disorder (ADHD), amyotrophic lateral sclerosis (ALS), autism spectrum disorder (ASD), anorexia nervosa (AN), bipolar disorder (BD), eating disorder (ED), generalized anxiety disorder (GAD), major depressive disorder (MDD), multiple sclerosis (MS), obsessive compulsive disorder (OCD), Parkinson's disease (PD), posttraumatic stress disorder (PTSD), spinal cord injury (SCI), schizophrenia, and stroke. We used A Measurement Tool to Assess Systematic Reviews (AMSTAR-2) to evaluate the quality of included SRs. We also created an evidence map showing the role of gut microbiota in neurological diseases and the certainty of the evidence.

Results

In total, 42 studies were included in this evidence mapping. Most findings were obtained from observational studies. According to the AMSTAR-2 assessment, 21 SRs scored "critically low" in terms of methodological quality, 16 SR scored "low," and 5 SR scored "moderate." A total of 15 diseases have been investigated for the potential association between gut microbiome alpha diversity and disease, with the Shannon index and Simpson index being the most widely studied. A total of 12 diseases were investigated for potential link between beta diversity and disease. At the phylum level, Firmicutes, Bacteroidetes, Actinobacteria, Proteobacteria, and Verrucomicrobia were more researched. At the genus level, Prevotella, Coprococcus, Parabacteroides, Phascolarctobacterium, Escherichia Shigella, Alistipes, Sutteralla, Veillonella, Odoribacter, Faecalibacterium, Bacteroides, Bifidobacterium, Dialister, and Blautia were more researched. Some diseases have been found to have specific flora changes, and some diseases have been found to have common intestinal microbiological changes.

Conclusion

We found varied levels of evidence for the associations between gut microbiota and neurological diseases; some gut microbiota increased the risk of neurological diseases, whereas others showed evidence of benefit that gut microbiota might be promising therapeutic targets for such diseases.