The Role of the Gut Microbiota in the Relationship Between Diet and Human Health.

The interplay between diet, the gut microbiome, and host health is complex. Diets associated with health have many similarities: high fiber, unsaturated fatty acids, and polyphenols while being low in saturated fats, sodium, and refined carbohydrates. Over the past several decades, dietary patterns have changed significantly in Westernized nations with the increased consumption of calorically dense ultraprocessed foods low in fiber and high in saturated fats, salt, and refined carbohydrates, leading to numerous negative health consequences including obesity, metabolic syndrome, and cardiovascular disease. The gut microbiota is an environmental factor that interacts with diet and may also have an impact on health outcomes, many of which involve metabolites produced by the microbiota from dietary components that can impact the host. This review focuses on our current understanding of the complex relationship between diet, the gut microbiota, and host health, with examples of how diet can support health, increase an individual's risk for disease, and be used as a therapy for specific diseases.

Evaluation of the Microbiome in Men Taking Pre-exposure Prophylaxis for HIV Prevention.

Tenofovir-based regimens as pre-exposure prophylaxis (PrEP) are highly effective at preventing HIV infection. The most common side-effect is gastrointestinal (GI) distress which may be associated with changes in the microbiome. Dysbiosis of the microbiome can have numerous health-related consequences. To understand the effect of PrEP on dysbiosis, we evaluated 27 individuals; 14 were taking PrEP for an average of 171 weeks. Sequencing of 16S rRNA was performed using self-collected rectal swabs. Mixed beta diversity testing demonstrated significant differences between PrEP and non-PrEP users with Bray-Curtis and unweighted UniFrac analyses (p = 0.05 and 0.049, respectively). At the genus level, there was a significant reduction in Finegoldia, along with a significant increase in Catenibacterium and Prevotella in PrEP users. Prevotella has been associated with inflammatory pathways, insulin resistance and cardiovascular disease, while Catenibacterium has been associated with morbid obesity and metabolic syndrome. Overall, these results suggest that PrEP may be associated with some degree of microbiome dysbiosis, which may contribute to GI symptoms. Long-term impact of these changes is unknown.

RESUMEN: Los regímenes basados en tenofovir como profilaxis previa a la exposición (PPrE) son muy eficaces en prevenir la infección por VIH. El efecto secundario más común es el malestar gastrointestinal (GI) que puede estar asociado con cambios en el microbioma. La disbiosis del microbioma puede tener numerosas consecuencias relacionadas con la salud. Para comprender el efecto de la PPrE sobre la disbiosis, evaluamos a 27 individuos; 14 de los individuos tomaron PPrE durante un promedio de 171 semanas. La secuenciación del ARNr 16S se realizó utilizando hisopos rectales recolectados por los propios pacientes. Las pruebas beta de diversidad mixta demostraron diferencias significativas entre los usuarios de PPrE y los que no utilizaron PPrE al analizarlos mediente Bray­Curtis y UniFrac no ponderados (p = 0,05 y 0,049, respectivamente). A nivel de género, hubo una reducción significativa de Finegoldia, junto con un aumento significativo de Catenibacterium y Prevotella en usuarios de PPrE. Prevotella se ha asociado con trayectorias inflamatorias, resistencia a insulina y enfermedades cardiovasculares, mientras que Catenibacterium se ha asociado con enfermedades como obesidad mórbida y padecimientos de síndrome metabólico. En general, estos resultados sugieren que la PPrE puede estar asociada con cierto grado de disbiosis del microbioma, lo que puede contribuir a los síntomas gastrointestinales. El impacto a largo plazo de estos cambios se desconoce.

Correction to: Presenting symptoms in inflammatory bowel disease: descriptive analysis of a community-based inception cohort.

An amendment to this paper has been published and can be accessed via the original article.

Long-Term Efficacy and Safety of Fecal Microbiota Transplantation for Treatment of Recurrent Clostridioides difficile Infection.

GOALS: We investigated the long-term efficacy and safety of fecal microbiota transplant (FMT) for the treatment of recurrent Clostridioides difficile infection (rCDI). BACKGROUND: FMT has emerged as a promising therapy for patients with rCDI unresponsive to standard medical therapy, though long-term efficacy and safety data are scarce. MATERIALS AND METHODS: A multicenter retrospective study was performed on patients treated with FMT for rCDI with ≥6 months of clinical follow-up post-FMT. Patients were contacted to document sustained efficacy, potential adverse events, and antibiotic exposure. The electronic medical record was reviewed to confirm patient-reported outcomes and obtain additional data. The primary outcome was sustained cure, as defined by the absence of Clostridioides difficile infection (CDI) at any timepoint after FMT. RESULTS: Of 528 patients treated, 207 were successfully contacted. The mean follow-up post-FMT was 34 (range: 6 to 84) months. One hundred fifty-seven patients (75.8%) reported sustained cure at the time of follow-up. One hundred patients (48%) reported the use of antibiotics for non-CDI indications post-FMT, of whom 11 (11%) had experienced CDI post-FMT. Fifty-two of the original 528 patients (9.8%) treated with FMT had died at the time of follow-up contact; none were felt attributable to the procedure. New medical conditions or diagnoses post-FMT were reported in 105 patients (50.5%). Fifteen reported improvement post-FMT in previously diagnosed medical conditions. CONCLUSIONS: In this largest and longest study to date on efficacy and safety after FMT for treatment of rCDI, we found that the majority of patients experienced long-term cure. Although a number of new conditions developed post-FMT, there was no clustering of diseases associated with dysbiosis.

Understanding the Scope of Do-It-Yourself Fecal Microbiota Transplant.

OBJECTIVES: Fecal microbiota transplantation (FMT) has emerged as an effective treatment option for Clostridioides difficile infection (CDI) and is considered an investigational therapy for a number of other diseases. Social media has facilitated widespread exposure of the public to the gut microbiome and FMT, ultimately acting as a catalyst for the Do-It-Yourself (DIY)-FMT movement. The aims of this study were to identify factors that influenced willingness to pursue DIY-FMT including common indications, screening processes, sample preparation, and self-reported efficacy and safety outcomes. METHODS: A twenty-five-point cross-sectional survey was posted online through the websites and social media pages of the Peggy Lillis Foundation, The Fecal Transplant Foundation, and The Power of Poop. Responses were cataloged through the Research Electronic Data Capture tool, and descriptive analyses were performed. RESULTS: Eighty-four respondents completed the survey between January 2018 and February 2019. The majority were female (71%) and white (92%). Most (80%) reported performing FMT on themselves; 87% used Internet resources to assist in the process, and 92% knew their stool donor. Inflammatory bowel disease (35%) and irritable bowel syndrome (29%) were the 2 most common conditions that respondents attempted to treat. Only 12% reported adverse events, whereas 82% reported improvement in their condition. DISCUSSION: DIY-FMT is being used for many indications, including those for which there is little evidence. There was a high self-reported success rate among respondents with few adverse events. There is a need for increased awareness around DIY-FMT and research around this phenomenon, which may impact public health.

Presenting symptoms in inflammatory bowel disease: descriptive analysis of a community-based inception cohort.

BACKGROUND: Few data are currently available on the initial presenting symptoms of patients with inflammatory bowel disease (IBD). METHODS: We evaluated the initial symptom presentation of patients with IBD in the Ocean State Crohn's and Colitis Area Registry (OSCCAR), a community-based inception cohort that enrolled Rhode Island IBD patients at time of diagnosis with longitudinal follow up. A 41-question symptom inventory was administered at time of enrollment to capture symptoms experienced during the 4 weeks preceding diagnosis of IBD. Frequencies of presenting symptoms were calculated. Principal component analysis (PCA) with promax rotation was used to examine possible symptom profiles among Crohn's disease (CD) and ulcerative colitis (UC) patients, respectively. Using the Scree plot, the 4-component solution was found to be optimal for both CD and UC. RESULTS: A total of 233 CD and 150 UC patients were included. The most common presenting symptoms in CD were tiredness/fatigue (80.6%) and abdominal pain (80.4%) while passage of blood with bowel movements (BM) (86.6%) and loose/watery BMs (86.5%) were most common in UC. The 5 symptoms with greatest differences between UC and CD were passage of blood with BM (UC 86.6%/CD 45.3%), urgent BM (UC 82.5%/CD 63.9%), passage of mucus with BM (UC 67.7%/CD 36.9%), passage of blood from the anus (UC 59.7%/CD 32.1%), and anxiety about distance from bathroom (UC 59%/CD 38.7%). The PCA analysis yielded a 4 symptom components solution for CD and UC. CONCLUSION: The most common presenting symptoms in CD are fatigue and abdominal pain while in UC bloody BM and diarrhea are most common. Distinct symptom phenotypes are seen with PCA analysis. Our study demonstrates symptomatic similarities and differences between CD and UC and suggests that patients may also be classified by symptom phenotype at time of diagnosis.

Targeting pyruvate carboxylase reduces gluconeogenesis and adiposity and improves insulin resistance.

We measured the mRNA and protein expression of the key gluconeogenic enzymes in human liver biopsy specimens and found that only hepatic pyruvate carboxylase protein levels related strongly with glycemia. We assessed the role of pyruvate carboxylase in regulating glucose and lipid metabolism in rats through a loss-of-function approach using a specific antisense oligonucleotide (ASO) to decrease expression predominantly in liver and adipose tissue. Pyruvate carboxylase ASO reduced plasma glucose concentrations and the rate of endogenous glucose production in vivo. Interestingly, pyruvate carboxylase ASO also reduced adiposity, plasma lipid concentrations, and hepatic steatosis in high fat-fed rats and improved hepatic insulin sensitivity. Pyruvate carboxylase ASO had similar effects in Zucker Diabetic Fatty rats. Pyruvate carboxylase ASO did not alter de novo fatty acid synthesis, lipolysis, or hepatocyte fatty acid oxidation. In contrast, the lipid phenotype was attributed to a decrease in hepatic and adipose glycerol synthesis, which is important for fatty acid esterification when dietary fat is in excess. Tissue-specific inhibition of pyruvate carboxylase is a potential therapeutic approach for nonalcoholic fatty liver disease, hepatic insulin resistance, and type 2 diabetes.