Autism spectrum disorder (ASD) is a severe brain development disorder that is characterized by deficits in social communication and restricted, repetitive and stereotyped behaviors. Accumulating evidence has suggested that gut microbiota disorders play important roles in gastrointestinal symptoms and neurodevelopmental dysfunction in ASD patients. Manipulation of the gut microbiota by fecal microbiota transplantation (FMT) was recently shown to be a promising therapy for the treatment of various diseases. Here, we performed a clinical trial to evaluate the effect of FMT on gastrointestinal (GI) and ASD symptoms and gut microbiota alterations in children with ASD. We found that there was a large difference in baseline characteristics of behavior, GI symptoms, and gut microbiota between children with ASD and typically developing (TD) control children. FMT could improve GI symptoms and ASD symptoms without inducing any severe complications. Similarly, FMT significantly changed the serum levels of neurotransmitters. We further observed that FMT could promote the colonization of donor microbes and shift the bacterial community of children with ASD toward that of TD controls. The abundance of Eubacterium coprostanoligenes pre-FMT was positively correlated with high GSRS scores, whereas a decrease in Eubacterium coprostanoligenes abundance induced by FMT was associated with the FMT response. Our data suggest that FMT might be a promising therapeutic strategy to improve the GI and behavioral symptoms of patients with ASD, possibly due to its ability to alter gut microbiota and highlight a specific microbiota intervention that targets Eubacterium coprostanoligenes that can enhance the FMT response. This trial was registered at the Chinese Clinical Trial Registry (www.chictr.org.cn) (trial registration number ChiCTR1800014745).

The occurrence and development of Parkinson's disease (PD) have been demonstrated to be related to gut dysbiosis, however, the impact of fecal microbiota transplantation (FMT) on microbiota engraftment in PD patients is uncertain. We performed a randomized, placebo-controlled trial at the Department of Neurology, Army Medical University Southwest Hospital in China (ChiCTR1900021405) from February 2019 to December 2019. Fifty-six participants with mild to moderate PD (Hoehn-Yahr stage 1-3) were randomly assigned to the FMT and placebo group, 27 patients in the FMT group and 27 in the placebo group completed the whole trial. During the follow-up, no severe adverse effect was observed, and patients with FMT treatment showed significant improvement in PD-related autonomic symptoms compared with the placebo group at the end of this trial (MDS-UPDRS total score, group×time effect, B = -6.56 [-12.98, -0.13], P < 0.05). Additionally, FMT improved gastrointestinal disorders and a marked increase in the complexity of the microecological system in patients. This study demonstrated that FMT through oral administration is clinically feasible and has the potential to improve the effectiveness of current medications in the clinical symptoms of PD patients.

The pathogenesis of ulcerative colitis (UC) is unclear, but it is generally believed to be closely related to an imbalance in gut microbiota. Roseburia intestinalis (R. intestinalis) might play a key role in suppressing intestinal inflammation, but the mechanism of its anti-inflammatory effect is unknown. In this study, we investigated the role of R. intestinalis and Toll-like receptor 5 (TLR5) in relieving mouse colitis. We found that R. intestinalis significantly upregulated the transcription of TLR5 in intestinal epithelial cells (IECs) and improved colonic inflammation in a colitis mouse model. The flagellin of R. intestinalis activated the release of anti-inflammatory factors (IL-10, TGF-β) and reduced inflammation in IECs. Furthermore, butyrate, the main metabolic product secreted by R. intestinalis, regulated the expression of TLR5 in IECs. Our data show that butyrate increased the binding of the transcription factor Sp3 (specificity protein 3) to the TLR5 promoter regions, upregulating TLR5 transcription. This work provides new insight into the anti-inflammatory effects of R. intestinalis in colitis and a potential target for UC prevention and treatment.

Ulcerative colitis (UC) is a chronic non-specific inflammatory disease that occurs in the colon and rectum. While fecal microbiota transplantation (FMT) is gaining attention as a clinical treatment of UC, the molecular mechanisms behind this effect have yet to be fully understood. A C57BL/6 mouse model was established to test whether FMT promotes the recovery of colon inflammation. Administration of 2% dextran sulfate sodium (DSS) for 7 days successfully induced acute colitis, as evidenced by diarrhea, hematochezia and colon shortening as well as a decrease in body weight. FMT alleviated the severity of colon mucosa injury and improved histological alterations compared with that of the DSS group. In addition, FMT promoted homeostasis of the intestinal microbiota. Furthermore, FMT upregulated the expression of aryl hydrocarbon receptor (AHR), interleukin-10 (IL-10), and transforming growth factor beta (TGF-β) in colon tissues. These results suggest that the significant anti-inflammatory effect of FMT may be attributed to its promotion of IL-10 and TGF-β production and AHR activation. Based on these results, FMT had a favorable therapeutic effect on DSS-induced colitis.

The community of gut microbes is a key factor controlling the intestinal barrier that communicates with the nervous system through the gut–brain axis. Based on our clinical data showing that populations of Roseburia intestinalis are dramatically decreased in the gut of patients with ulcerative colitis, we studied the efficacy of a strain belonging to this species in the context of colitis and stress using animal models. Dextran sulfate sodium was used to induce colitis in rats, which then underwent an enema with R. intestinalis as a treatment. The disease activity index, fecal changes and body weight of rats were recorded to evaluate colitis, while histological and immunohistochemical analyses were carried out to examine colon function, and 16S rRNA sequencing was performed to evaluate the gut microbiota change. Behavioral assays and immunohistochemical staining of brain were performed to assess the effect of R. intestinalis on the gut–brain axis. Colitis-related symptoms in rats were significantly relieved after R. intestinalis enema, and the stool traits and colon length of rats were significantly recovered after treatment. The gut epithelial integrity and intestinal barrier were restored in treated rats, as evidenced by the higher expression of Zo-1 in colon tissues, accompanied by the restoration of gut microbiota. Meanwhile, depressive-like behaviors of rats were reduced after treatment, and laboratory experiments on neuronal cells also showed that IL-6, IL-7 and 5-HT were downregulated by R. intestinalis treatment in both serum and brain tissue, while Iba-1 expression was reduced in treated rats. The administration of R. intestinalis contributes to restoration of the gut microbiota, promoting colon repair and the recovery of gastrointestinal function. These alterations are accompanied by the relief of depressive-like behaviors through a process modulated by the neuronal network and the regulation of inflammation by the gut–brain axis.

Background: Small intestinal bacterial overgrowth (SIBO) is characterized by the condition that bacteria overgrowth in the small intestine. Fecal microbiota transplantation (FMT) has been applied as an effective tool for reestablishing the structure of gut microbiota. However, whether FMT could be applied as a routine SIBO treatment has not been investigated. Methods: In this trial, 55 SIBO patients were enrolled. All participants were randomized in two groups, and were given FMT capsule or placebo capsules once a week for 4 consecutive weeks. Measurements including the lactulose hydrogen breath test gastrointestinal symptoms, as well as fecal microbiota diversity were assessed before and after FMT therapy. Results: Gastrointestinal symptoms significantly improved in SIBO patients after treatment with FMT compared to participants in placebo group. The gut microbiota diversity of FMT group had a significant increase, while placebo group showed none. Conclusions: This study suggests that applying FMT for patients with SIBO can alleviate gastrointestinal symptoms, indicating that FMT may be a promising and novel therapeutic regimen for SIBO. Trial registry This study was retrospectively registered with the Chinese Clinical Trial registry on 2019.7.10 (ID: ChiCTR1900024409, http://www.chictr.org.cn).