Multi-Time-Point Fecal Sampling in Human and Mouse Reveals the Formation of New Homeostasis in Gut Microbiota after Bowel Cleansing

Effects of Different Bowel Preparation Regimens and Age Factors on the Gut Microbiota: A Prospective Randomized Controlled Study

BACKGROUND

Opinions about the impact of bowel preparation on the gut microbiota are divided. This study investigated the effects of different regimens on the gut microbiota post-bowel preparation and the differences in responses across different age groups.

METHODS

This single-center, prospective, randomized, controlled clinical trial included 194 patients. Patients were categorized into two groups: one group receiving polyethylene glycol (n = 108) and one receiving sodium picosulfate (n = 86) for bowel preparation. Fecal samples were collected at baseline and on days 7 and 14 post-bowel preparation. The microbiota's diversity and composition were analyzed using 16S ribosomal RNA gene sequencing, followed by comparative analyses.

RESULTS

The gut microbiota's abundance and diversity in patients significantly decreased post-bowel preparation, which did not recover to the level of pre-bowel preparation on Day 14. When comparing different regimens, the polyethylene glycol and sodium picosulfate groups recovered faster in richness and diversity, respectively. Patients aged < 65 years had higher richness and diversity of the gut microbiota, whereas the microbiota structure in those aged ≥ 65 years returned to the baseline state faster. The structure of beta diversity is significantly altered and did not return in the short term. However, in the elderly population aged ≥ 65 years, it can rebound quickly. This study also identified a number of significantly altered bacterial genera.

CONCLUSIONS

Following the use of different bowel preparation regimens, the gut microbiota recovers in diverse ways, with older people over 65 experiencing a faster recovery of the microbial structure.

Depressive Symptoms and Gut Microbiota after Bowel Preparation and Colonoscopy: A Pre-Post Intervention Study

Mechanical bowel preparation (MBP) is essential for visualisation of the colon during colonoscopy. Previous studies have identified changes in gut microbiota composition after MBP and colonoscopy. Considering the gut microbiota is increasingly implicated in psychiatry, we explored the potential impact of this intervention on mood and the microbiota-gut-brain axis. We conducted a pre-post intervention study in adults, with timepoints of one week before and one month after MBP and colonoscopy. Our primary outcome was change in average Hospital Anxiety and Depression Scale depression sub-scores. We examined changes in average anxiety, stress, and quality of life scores and gut microbiota composition using 16S rRNA sequencing. We further explored associations between changes in depressive symptoms and gut microbiota and conducted post hoc analyses to explore potential effect modifiers. Average depressive symptom scores decreased one month post-procedure compared to baseline (n = 59; adjusted β = -0.64; 95%CI: -1.18, -0.11). Irritable bowel syndrome (IBS) appeared to moderate this relationship (β = 1.78; 95%CI: 0.292, 3.26); depressive symptoms increased in those with, and decreased in those without, IBS. Reduced alpha diversity, modest effects on beta-diversity, and increases in health-associated genera were observed one month post-procedure. Increases in the CLR-transformed abundances of Ruminococcaceae UCG-009 were associated with improvements in depressive symptoms. There is preliminary evidence of a potential mental health effect of MBP and colonoscopy, particularly for those with IBS, which may be associated with changes to the gut microbiota. Further research is required to confirm these findings and their clinical relevance.

Galacto-Oligosaccharides and the Elderly Gut: Implications for Immune Restoration and Health

The increasing prevalence of noncommunicable diseases in the aging population has been correlated with a decline in innate and adaptive immune responses; hence, it is imperative to identify approaches to improve immune function, prevent related disorders, and reduce or treat age-associated health complications. Prebiotic supplementation is a promising approach to modulate the gut microbiome and immune system, offering a potential strategy to maintain the integrity of immune function in older individuals. This review summarizes the current research on prebiotic galacto-oligosaccharide (GOS) immunomodulatory mechanisms mediated by bacterial-derived metabolites, including short-chain fatty acids and secondary bile acids, to maintain immune homeostasis. The potential applications of GOS as immunotherapy for age-related disease prevention in older individuals are also highlighted. This aligns with the global shift toward proactive healthcare and emphasizes the significance of early intervention in directing an individual's health trajectory.

Induction of autism-related behavior in male mice by early-life vitamin D deficiency: association with disruption of the gut microbial composition and homeostasis

Vitamin D deficiency (VDD) during early life emerges as a potential risk factor for autism spectrum disorder (ASD). Individuals with autism commonly exhibit lower vitamin D (VD) levels compared to the general population, and VD deficiency is prevalent during pregnancy and lactation. Moreover, gastrointestinal comorbidity, prevalent in ASD patients, correlates closely with disruptions in the gut microbiota and altered intestinal permeability. Therefore, it is fascinating and significant to explore the effects of maternal VD deficiency during pregnancy and lactation on the maturation of the gut microbiota of the offspring and its relevance to autism spectrum disorders. In this study, we established maternal pregnancy and lactation VD-deficient mouse models, employed shotgun macrogenomic sequencing to unveil alterations in the gut microbiome of offspring mice, and observed autism-related behaviours. Furthermore, fecal microbial transplantation (FMT) reversed repetitive and anxious behaviours and alleviated social deficits in offspring mice by modulating the gut microbiota and increasing short-chain fatty acid levels in the cecum, along with influencing the concentrations of claudin-1 and occludin in the colon. Our findings confirm that VDD during pregnancy and lactation is a risk factor for autism in the offspring, with disturbances in the structure and function of the offspring's gut microbiota contributing at least part of the effect. The study emphasises the importance of nutrition and gut health early in life. Simultaneously, this study further demonstrates the effect of VDD on ASD and provides potential ideas for early prevention and intervention of ASD.

Fecal microbiota transplantation for the treatment of irritable bowel syndrome: A systematic review and meta-analysis

BACKGROUND

Irritable bowel syndrome (IBS) is the most prevalent gastrointestinal disorder in developed countries and reduces patients’ quality of life, hinders their ability to work, and increases health care costs. A growing number of trials have demonstrated an aberrant gut microbiota composition in IBS, also known as ‘gut dysbiosis’. Fecal microbiota transplantation (FMT) has been suggested as a treatment for IBS.

AIM

To assess the efficacy and safety of FMT for the treatment of IBS.

METHODS

We searched Cochrane Central, MEDLINE, EMBASE and Web of Science up to 24 October 2022 for randomised controlled trials (RCTs) investigating the effectiveness of FMT compared to placebo (including autologous FMT) in treating IBS. The primary outcome was the number of patients with improvements of symptoms measured using a validated, global IBS symptoms score. Secondary outcomes were changes in quality-of-life scores, non-serious and serious adverse events. Risk ratios (RR) and corresponding 95%CI were calculated for dichotomous outcomes, as were the mean differences (MD) and 95%CI for continuous outcomes. The Cochrane risk of bias tool was used to assess the quality of the trials. GRADE criteria were used to assess the overall quality of the evidence.

RESULTS

Eight RCTs (484 participants) were included in the review. FMT resulted in no significant benefit in IBS symptoms three months after treatment compared to placebo (RR 1.19, 95%CI: 0.68-2.10). Adverse events were reported in 97 participants in the FMT group and in 45 participants in the placebo group (RR 1.17, 95%CI: 0.63-2.15). One serious adverse event occurred in the FMT group and two in the placebo group (RR 0.42, 95%CI: 0.07-2.60). Endoscopic FMT delivery resulted in a significant improvement in symptoms, while capsules did not. FMT did not improve the quality of life of IBS patients but, instead, appeared to reduce it, albeit non significantly (MD -6.30, 95%CI: -13.39-0.79). The overall quality of the evidence was low due to moderate-high inconsistency, the small number of patients in the studies, and imprecision.

CONCLUSION

We found insufficient evidence to support or refute the use of FMT for IBS. Larger trials are needed.

Rationale for Colonic Pre-Habilitation Prior to Restoration of Gastrointestinal Continuity

The emergence of the gut microbiome as a complex ecosystem that plays a key role in human heath and disease has touched virtually every aspect of medical and surgical care. With the advent of next-generation technology to interrogate the microbiome at the level of its membership, community structure and production of metabolites, applying measures by which the gut microbiome can be manipulated to the advantage of both the patient and provider is now possible. Among the many proposed methods, the most practical and promising is dietary pre-habilitation of the gut microbiome prior to high-risk anastomotic surgery. In this review, we will outline the scientific rationale and molecular underpinning that support dietary pre-habilitation as a practical and deliverable method to prevent complications after high-risk anastomotic surgery.

Rationale behind phosphate therapy to modulate the gut microbiome and protect against surgery-related infection

Despite major advances in infection control and the ever increasing use of broader spectrum antibiotics in surgery, postoperative infections continue to occur under the best of care and in the best institutions. Postoperative infections, also termed "surgical site infections (SSIs), can range from superficial wound infections to deep organ space infections. SSIs can be superficial and only require medical treatment (i.e antibiotics), whereas others such as deep organ space infections resulting from an anastomotic leak can require multiple surgeries leading to sepsis and occasionally shock and death. Many if not most stakeholders in the field including surgeons, infectious disease specialists, infection control nurses, etc., in general advocate the use of prophylactic antibiotics and the enforcement of greater levels of sterility reasoning that all postoperative infections must arise from some type of direct contamination event. In this piece, the alternative view is presented that today, in the era of mandated asepsis protocols, enhanced recovery programs, and enforcement of prophylactic antibiotics in all cases, many if not most postoperative infections and SSIs occur from pathogens endogenous to the patient not from sources exogenous to the patient. It is also suggested that applying broader antibiotic coverage in elective surgery is neither an evolutionarily stable strategy nor inexorable in the context of emerging knowledge in the field of gut ecology. Here this concept is reviewed and the rationale behind using agents that preserve the gut microbiome and attenuate pathogen virulence in lieu of applying broader spectrum antibiotics and greater levels of sterility.