Reactivation of Crohn’s colitis in an adolescent following serial autologous fecal transplants for diversion colitis: A case report with multiomic characterization

Autologous fecal transplant (AFT, transfer of ileostomy feces to the colon) for diversion colitis (DC) has not yet been described in children or adolescents. We performed serial AFTs in a 16-year-old with Crohn’s disease and DC. As evidenced by endoscopic, histologic, laboratory, and multiomic profiling of the colon, the first AFT led to interval improvement in DC, whereas the second AFT reactivated Crohn’s colitis. These findings ultimately guided shared decision-making towards total colectomy.

A short chain fatty acid–centric view of Clostridioides difficile pathogenesis

Clostridioides difficile is an opportunistic diarrheal pathogen responsible for significant morbidity and mortality worldwide. A disrupted (dysbiotic) gut microbiome, commonly engendered by antibiotic treatment, is the primary risk factor for C. difficile infection, highlighting that C. difficile–microbiome interactions are critical for determining the fitness of this pathogen. Here, we review short chain fatty acids (SCFAs): a major class of metabolites present in the gut, their production by the gut microbiome, and their impacts on the biology of the host and of C. difficile. We use these observations to illustrate a conceptual model whereby C. difficile senses and responds to SCFAs as a marker of a healthy gut and tunes its virulence accordingly in order to maintain dysbiosis. Future work to learn the molecular mechanisms and genetic circuitry underlying the relationships between C. difficile and SCFAs will help to identify precision approaches, distinct from antibiotics and fecal transplant, for mitigating disease caused by C. difficile and will inform similar investigations into other gastrointestinal pathogens.

Incongruence between dominant commensal donor microbes in recipient feces post fecal transplant and response to anti-PD-1 immunotherapy

Background To understand inter-individual variability of fecal microbe transplantation (FMT) to enhance anti-PD-1 immunotherapy (IT) for melanoma, we analyzed the data sets from two recent publications with a microbial strain-tracking tool to determine if donor strains were dominant in the recipient feces following FMT. Results Analysis of the Baruch et al. data set found that the presence of commensal donor microbes in recipient feces post-FMT did not correlate with the patient response to IT. From the Davar et al., data set, we found 4 patients that responded to IT had donor’s related strain post-FMT, while 2 patients that did not respond to the IT also had donor’s strain post-FMT. Importantly, we identified no donor microbes in the feces in one recipient post-FMT that responded to IT. Furthermore, in depth analysis from two patients who responded to IT revealed both donor and recipient strains at different times post-FMT. Colonization of the gastrointestinal tract niches is important for the interaction with the host immune system. Using a separate data set, we show that mucosa from the cecum, transverse colon, and sigmoid colon share strains, providing a large reservoir of niches containing recipient microbes. Conclusions We demonstrated using strain-tracking analysis individual variation with the respect to the presence of fecal dominant donor microbes in the recipient following FMT that did not correlate with the response to anti-PD-1 immunotherapy. The inter-individual differences of FMT to enhance IT might be explained by the variability of the donor microbes to occupy and outcompete recipient microbes for the gastrointestinal niches. The result from our study supports the use of new approaches to clear the niches in the gastrointestinal tract to promote donor colonization to reduce inter-individual variability of IT for melanoma and potentially other cancers.

Fecal Transplant and Bifidobacterium Treatments Modulate Gut Clostridium Bacteria and Rescue Social Impairment and Hippocampal BDNF Expression in a Rodent Model of Autism

Autism is associated with gastrointestinal dysfunction and gut microbiota dysbiosis, including an overall increase in Clostridium. Modulation of the gut microbiota is suggested to improve autistic symptoms. In this study, we explored the implementation of two different interventions that target the microbiota in a rodent model of autism and their effects on social behavior: the levels of different fecal Clostridium spp., and hippocampal transcript levels. Autism was induced in young Sprague Dawley male rats using oral gavage of propionic acid (PPA) for three days, while controls received saline. PPA-treated animals were divided to receive either saline, fecal transplant from healthy donor rats, or Bifidobacterium for 22 days, while controls continued to receive saline. We found that PPA attenuated social interaction in animals, which was rescued by the two interventions. PPA-treated animals had a significantly increased abundance of fecal C. perfringens with a concomitant decrease in Clostridium cluster IV, and exhibited high hippocampal Bdnf expression compared to controls. Fecal microbiota transplantation or Bifidobacterium treatment restored the balance of fecal Clostridium spp. and normalized the level of Bdnf expression. These findings highlight the involvement of the gut–brain axis in the etiology of autism and propose possible interventions in a preclinical model of autism.

Prospective manipulation of the gut microbiome with Microbial Ecosystem Therapeutic 4 (MET4) in locoregionally advanced oropharyngeal squamous cell carcinoma (LA-OPSCC) undergoing primary chemoradiation (ROMA2).

6059 Background: Therapeutic manipulation of the gut microbiome in cancer patients (pts) is an area of active investigation. MET4 (NuBiyota) is an oral alternative to fecal transplant consisting of a mixture of human gut bacteria associated with immunotherapy (IO) response. We previously reported variation in IO-responsive taxa across stages in human papilloma virus related (HPV+) LA-OPSCC pts treated with chemoradiotherapy (CRT) (Oliva et al., ASCO 2020). ROMA-2 is the first interventional study evaluating the safety, feasibility and ecological effect of MET4, in combination with definitive CRT in HPV+ LA-OPSCC (NCT03838601). Methods: This is an investigator-initiated study of pts with HPV+ LA-OPSCC treated with standard of care CRT. MET4 is administered daily until week 4 of CRT or unacceptable toxicity. Stool samples are collected at baseline, week 4, week 8-10, and 2-months post CRT. Bacterial V4 16S rDNA was extracted from stool and sequenced. Microbiome analyses were conducted in R using DADA2, phyloseq and DESeq2. Results: As of February 11 2021, 25 pts have been enrolled. A total of 50 stool samples from the first 14 pts were collected (98% adherence) and analyzed. Baseline cohort characteristics: median age = 62.5 (range, 48-69); Stage I/II/III = 5/1/8; use of antibiotics = 1pt. 3 pts did not complete the 3-week course of MET4 treatment due to non-compliance (n = 1), withdrawal of consent (n = 1) and grade 2 diarrhea (n = 1). Other reported MET4-related adverse events (all grade 1) included bloating (n = 2), flatulence (n = 1) and belching (n = 1). No longitudinal changes in alpha-diversity were seen from baseline through follow up. Administration of MET4 resulted in a transient trend towards increased cumulative MET4 taxa relative abundance (RA) by week 4. Stage III patients demonstrated the lowest MET4 taxa RA at baseline, and the greatest increase in MET4 taxa RA from baseline to week 4. By week 4 the following taxa in all pts were increased compared to baseline: Eubacterium hallii (21.71 Log2Fold change[L2FC], padj < 0.001) and Parabacteroides johnsonii (23.67 L2FC, padj < 0.001). An increase in the following taxa was observed by weeks 8-10 compared to baseline: Akkermansia muciniphilla (3.75 L2FC, padj = 0.027), Bacteroides fragilis (6.73 L2FC, padj = 0.010), Alistipes onderdonkii (3.30 L2FC, padj = 0.049) and Parabacteroides distasonis (24.43 L2FC, padj < 0.001). Conclusions: Manipulation of the gut microbiota in these pts was feasible and safe. MET4-induced ecological changes are heterogenous and vary by taxa. MET4 taxa implicated in IO-response were increased by week 4 and week 8-10. This increase was higher in pts with stage III disease. These data suggest that specific subgroups may benefit from combination IO therapy and may guide pt selection for further interventional clinical trial design. Clinical trial information: NCT03838601.

Ge-Gen-Jiao-Tai-Wan Affects Type 2 Diabetic Rats by Regulating Gut Microbiota and Primary Bile Acids

The Ge-Gen-Jiao-Tai-Wan (GGJTW) formula has been used to treat type 2 diabetes mellitus (T2DM) in China for a long time. Our previous study has proved that GGJTW could alleviate the type 2 diabetic symptoms, but the underlying mechanisms are still unclear. This study aimed to investigate the changes in gut microbiota and primary bile acids (PBAs) to determine the potential mechanisms of GGJTW in treating T2DM.The fecal transplant method and pseudogerm-free rats were used in our study.The16S rRNA gene sequencing method was used to analyze the changes in the intestinal flora, and PBAs in the colon contents were detected. Finally, the expression of farnesoid X receptor (FXR), G protein-coupled membrane receptor 5 (TGR5), and glucagon-like peptide-1 (GLP-1) was assessed. Following GGJTW treatment, we observed a decrease in blood glucose levels and improvements in glucose tolerance and serum lipid levels. Furthermore, we found that GGJTW could regulate the composition of the gut microbiota and upregulate the diabetic beneficial phylum Firmicutes and bile-acid-related genus Lactobacillus. PBAs in the colon contents were increased in the GGJTW-treated group, accompanied by upregulated expression of the bile acid receptors FXR and TGR5 and increased concentrations of GLP-1. These results indicated that GGJTW could alleviate symptoms of type 2 diabetic rats by regulating the gut microbiota, promoting the production of PBAs, and upregulating the PBA-FXR/TGR5-GLP-1 pathway.

The Role of Gut Microbiota in Duodenal-Jejunal Bypass Surgery-Induced Improvement of Hepatic Steatosis in HFD-Fed Rats

Bariatric surgery including duodenal-jejunal bypass surgery (DJB) improves insulin sensitivity and reduces obesity-associated inflammation. However, the underlying mechanism for such an improvement is still incompletely understood. Our objective was to investigate the role of the gut microbiota in DJB-associated improvement of hepatic steatosis in high fat diet (HFD)-fed rats. To study this, hepatic steatosis was induced in male adult Sprague-Dawley rats by feeding them with a 60% HFD. At 8 weeks after HFD feeding, the rats were subjected to either DJB or sham operation. HFD was resumed 1 week after the surgery for 3 more weeks. In additional groups of animals, feces were collected from HFD-DJB rats at 2 weeks after DJB. These feces were then transplanted to HFD-fed rats without DJB at 8 weeks after HFD feeding. Hepatic steatosis and fecal microbiota were analyzed at 4 weeks after surgery or fecal transplantation. Our results showed that DJB alleviated hepatic steatosis in HFD-fed rats. Fecal microbiota analysis showed that HFD-fed and standard diet-fed rats clustered differently. DJB induced substantial compositional changes in the gut microbiota. The fecal microbiota of HFD-fed rats received fecal transplant from DJB rats overlapped with that of HFD-DJB rats. Treatment of rats with HFD-induced liver lesions by fecal transplant from DJB-operated HFD-fed rats also attenuated hepatic steatosis. Thus, alterations in the gut microbiota after DJB surgery are sufficient to attenuate hepatic steatosis in HFD-fed rats. Targeting the gut microbiota could be a promising approach for preventing or treating human NAFLD.