Racial and Ethnic Minorities With Acute Pancreatitis Live in Neighborhoods With Higher Social Vulnerability Scores.

OBJECTIVES: The primary objective was to determine differences in Social Vulnerability Index (SVI) scores among minorities (African-Americans and Hispanics) with acute pancreatitis (AP) compared with non-Hispanic whites (NHWs) with AP. The secondary objectives were to determine differences in diet, sulfidogenic bacteria gene copy numbers (gcn) and hydrogen sulfide (H2S) levels between the 2 groups. MATERIALS AND METHODS: Patients with AP were enrolled during hospitalization (n = 54). Patient residential addresses were geocoded, and the Centers for Disease Control and Prevention's SVI scores were appended. Dietary intake and serum H2S levels were determined. Microbial DNAs were isolated from stool, and gcn of sulfidogenic bacteria were determined. RESULTS: Minorities had higher SVI scores compared with NHWs ( P = 0.006). They also had lower consumption of beneficial nutrients such as omega-3 fatty acids [stearidonic ( P = 0.019), and eicosapentaenoic acid ( P = 0.042)], vitamin D ( P = 0.025), and protein from seafood ( P = 0.031). Lastly, minorities had higher pan-dissimilatory sulfite reductase A ( pan-dsrA ) gcn ( P = 0.033) but no significant differences in H2S levels ( P = 0.226). CONCLUSION: Minorities with AP have higher SVI compared with NHWs with AP. Higher SVI scores, lower consumption of beneficial nutrients, and increased gcn of pan-dsrA in minorities with AP suggest that neighborhood vulnerability could be contributing to AP inequities.

Post-traumatic stress disorder symptoms are frequent among inflammatory bowel disease patients of South Asian descent-A case-control study.

BACKGROUND: Post-traumatic stress (PTS) is the psycho-physiological response to a traumatic or life-threatening event and is implicated in inflammatory bowel disease (IBD). IBD-PTS is present in up to 30% of white, non-Hispanic patients. The rates of IBD in Asian populations are expanding, making the exploration of IBD-PTS in this population imperative. METHODS: Adult patients of South/Southeast (S/SE) Asian decent with IBD for more than 6 months were recruited online via social media and patient-support groups. Participants completed the post-traumatic stress disorder (PTSD) Checklist-5 (PCL-5), the United States National Institutes of Health's Patient-Reported Outcomes Measurement Information System (NIH-PROMIS) -43 profile and demographics. S/SE Asian participants were age and sex matched (1:2) with randomly selected white, non-Hispanic controls. Statistical analyses evaluated differences in IBD-PTS symptoms between groups, the relationship between disease severity and health-related quality of life (HRQoL) and predictors of IBD-PTS severity. RESULTS: Forty-seven per cent of the 51 S/SE Asian participants met the diagnostic cut-off for PTSD on the PCL-5 compared to 13.6% of 110 IBD controls. The mean global score on the PCL-5 was three times higher in S/SE Asians. Patients of S/SE Asian decent were over five times more likely to have PTSD due to their IBD experiences than controls, nearly doubling when controlling for disease activity. More severe IBD-PTS was present in S/SE Asian patients with active disease and those with extraintestinal manifestations. Higher global levels of IBD-PTS were associated with poorer HRQoL in S/SE Asians where increased hyperarousal from IBD-PTS predicted more sleep disturbance. CONCLUSIONS: S/SE Asian patients are five times more likely to experience IBD-PTS than their white, non-Hispanic counterparts. Several cultural factors lead to IBD-PTS in S/SE Asian patients that must be considered by IBD providers. Preventing, screening for and treating IBD-PTS in this population appears warranted.

Modulating microbiome-immune axis in the deployment-related chronic diseases of Veterans: report of an expert meeting.

The present report summarizes the United States Department of Veterans Affairs (VA) field-based meeting titled "Modulating microbiome-immune axis in the deployment-related chronic diseases of Veterans." Our Veteran patient population experiences a high incidence of service-related chronic physical and mental health problems, such as infection, irritable bowel syndrome (IBS), inflammatory bowel disease (IBD), various forms of hematological and non-hematological malignancies, neurologic conditions, end-stage organ failure, requiring transplantation, and posttraumatic stress disorder (PTSD). We report the views of a group of scientists who focus on the current state of scientific knowledge elucidating the mechanisms underlying the aforementioned disorders, novel therapeutic targets, and development of new approaches for clinical intervention. In conclusion, we dovetailed on four research areas of interest: 1) microbiome interaction with immune cells after hematopoietic cell and/or solid organ transplantation, graft-versus-host disease (GVHD) and graft rejection, 2) intestinal inflammation and its modification in IBD and cancer, 3) microbiome-neuron-immunity interplay in mental and physical health, and 4) microbiome-micronutrient-immune interactions during homeostasis and infectious diseases. At this VA field-based meeting, we proposed to explore a multi-disciplinary, multi-institutional, collaborative strategy to initiate a roadmap, specifically focusing on host microbiome-immune interactions among those with service-related chronic diseases to potentially identify novel and translatable therapeutic targets.

Comparison of gut microbiome composition in colonic biopsies, endoscopically-collected and at-home-collected stool samples.

Aim: The goal of this study is to compare microbiome composition in three different sample types in women, namely stool brought from home vs. solid stool samples obtained at the time of an unprepped sigmoidoscopy vs. biopsies of the colonic mucosa at the time of an unprepped sigmoidoscopy, using alpha- and beta-diversity metrics following bacterial 16S rRNA sequencing. The findings may have relevance to health and disease states in which bacterial metabolism has a significant impact on molecules/metabolites that are recirculated between the gut lumen and mucosa and systemic circulation, such as estrogens (as in breast cancer) or bile acids. Methods: Concomitant at-home-collected stool, endoscopically-collected stool, and colonic biopsy samples were collected from 48 subjects (24 breast cancer, 24 control.) After 16S rRNA sequencing, an amplicon sequence variant (ASV) based approach was used to analyze the data. Alpha diversity metrics (Chao1, Pielou's Evenness, Faith PD, Shannon, and Simpson) and beta diversity metrics (Bray-Curtis, Weighted and Unweighted Unifrac) were calculated. LEfSe was used to analyze differences in the abundance of various taxa between sample types. Results: Alpha and beta diversity metrics were significantly different between the three sample types. Biopsy samples were different than stool samples in all metrics. The highest variation in microbiome diversity was noted in the colonic biopsy samples. At-home and endoscopically-collected stool showed more similarities in count-based and weighted beta diversity metrics. There were significant differences in rare taxa and phylogenetically-diverse taxa between the two types of stool samples. Generally, there were higher levels of Proteobacteria in biopsy samples, with significantly more Actinobacteria and Firmicutes in stool (all p < 0.001, q-value < 0.05). Overall, there was a significantly higher relative abundance of Lachnospiraceae and Ruminococcaceae in stool samples (at-home collected and endoscopically-collected) and higher abundances of Tisserellaceae in biopsy samples (all p < 0.001, q-value < 0.05). Conclusion: Our data shows that different sampling methods can impact results when looking at the composition of the gut microbiome using ASV-based approaches.

Diet, Gut Microbiome, and Their End Metabolites Associate With Acute Pancreatitis Risk.

INTRODUCTION: Diet and decreased gut microbiome diversity has been associated with acute pancreatitis (AP) risk. However, differences in dietary intake, gut microbiome, and their impact on microbial end metabolites have not been studied in AP. We aimed to determine differences in (i) dietary intake (ii) gut microbiome diversity and sulfidogenic bacterial abundance, and (iii) serum short-chain fatty acid (SCFA) and hydrogen sulfide (H 2 S) concentrations in AP and control subjects. METHODS: This case-control study recruited 54 AP and 46 control subjects during hospitalization. Clinical and diet data and stool and blood samples were collected. 16S rDNA sequencing was used to determine gut microbiome alpha diversity and composition. Serum SCFA and H 2 S levels were measured. Machine learning (ML) model was used to identify microbial targets associated with AP. RESULTS: AP patients had a decreased intake of vitamin D 3 , whole grains, fish, and beneficial eicosapentaenoic, docosapentaenoic, and docosahexaenoic acids. AP patients also had lower gut microbiome diversity ( P = 0.021) and a higher abundance of sulfidogenic bacteria including Veillonella sp. and Haemophilus sp., which were associated with AP risk. Serum acetate and H 2 S concentrations were significantly higher in the AP group ( P < 0.001 and P = 0.043, respectively). ML model had 96% predictive ability to distinguish AP patients from controls. DISCUSSION: AP patients have decreased beneficial nutrient intake and gut microbiome diversity. An increased abundance of H 2 S-producing genera in the AP and SCFA-producing genera in the control group and predictive ability of ML model to distinguish AP patients indicates that diet, gut microbiota, and their end metabolites play a key role in AP.

Hospitalization Experiences and Post-traumatic Stress in Inflammatory Bowel Disease: Opportunities for Change.

INTRODUCTION: Medical trauma related to IBD (IBD-PTS) affects approximately 25% of patients and is associated with poor outcomes. Prior studies identify common hospitalization experiences as potentially traumatic but have not measured risk relationships for the development of IBD-PTS. We aim to investigate what aspects of hospitalizations may increase the chance of medical trauma and IBD-PTS development. METHODS: Adult patients with IBD enrolled in the IBD Partners database were recruited. Study specific questionnaires included PTSD checklist, 5th edition (PCL-5), patient experience questionnaire, and items about the patient's most stressful hospitalization and nonhospital sources of medical trauma. Established criteria for the PCL-5 identified significant IBD-PTS symptoms (re-experiencing, avoidance, mood change, hyperarousal, global diagnosis). Select disease and treatment information was obtained from the main IBD Partners dataset. Univariate and multivariate statistics evaluated the relationships between hospitalization data and IBD-PTS. RESULTS: There were 639 participants with at least 1 hospitalization for IBD included. Approximately two-thirds had Crohn's disease; most were White, non-Hispanic, female, middle-aged, and reported their IBD as being in remission. Forty percent of patients stated a hospitalization was a source of IBD-PTS. Frequent anxiety while hospitalized increased the odds of IBD-PTS 2 to 4 times; similar relationships existed for pain/pain control. Higher quality communication, information, and listening skills reduced the odds of IBD-PTS, albeit marginally. CONCLUSIONS: Patients with IBD consistently cite hospitalizations as potential sources of medical trauma. Poorly managed anxiety and pain demonstrate the greatest chance for IBD-PTS development. Gender and racial/ethnic differences emerged for these risks. Positive interactions with the medical team may help mitigate in-hospital IBD-PTS development.

This study finds IBD patients with the poorest hospital experiences and those with poor pain and anxiety control are at the highest risk of developing post-traumatic stress disorder symptoms due to medical trauma. Medical staff behavior is an important consideration.

Posttraumatic Stress in Patients With Inflammatory Bowel Disease: Prevalence and Relationships to Patient-Reported Outcomes.

BACKGROUND: Patients with chronic illness are at increased risk for traumatic stress because of medical trauma. Initial studies of posttraumatic stress (PTS) in patients with inflammatory bowel disease (IBD) have found that approximately one-third of patients may experience significant PTS symptoms including flashbacks, nightmares, hypervigilance, disrupted sleep, and low mood. We aim to better characterize PTS in IBD and its relationship with patient outcomes in a large cohort of patients with IBD. METHODS: Adult patients registered with the Crohn's & Colitis Foundation/University of North Carolina IBD Partners database were invited to complete a supplementary survey between February and July 2020. The Post Traumatic Stress Disorder Checklist-5th edition was administered as a supplemental survey. Additional data from IBD Partners included disease severity, surgery and hospital history, demographics, and health care utilization. RESULTS: A total of 797 patients participated (452 with Crohn disease, 345 with ulcerative colitis). No impacts on response patterns because of the COVID-19 pandemic were found. Although 5.6% of the sample reported an existing PTS diagnosis because of IBD experiences, 9.6% of participants met the full IBD-related PTS diagnostic criteria per the Post Traumatic Stress Disorder Checklist-5th edition. Female patients, younger patients, those with less educational attainment, non-White patients, and Hispanic patients reported higher levels of PTS symptoms. Patients with higher PTS symptoms were more likely to have been hospitalized, have had surgery, have more severe symptoms, and not be in remission. Increased PTS was also associated with increased anxiety, depression, pain interference, fatigue, and health care utilization. CONCLUSIONS: The present findings support prior research that approximately one-quarter to one-third of patients with IBD report significant symptoms of PTS directly from their disease experiences, and certain demographic groups are at higher risk. In addition, PTS is associated with several IBD outcomes. Patients with higher PTS symptoms are less likely to be in remission and may utilize more outpatient gastrointestinal services. Intervention trials to mitigate PTS symptoms in patients with IBD are warranted.

Patient Perspectives on Medical Trauma Related to Inflammatory Bowel Disease.

Post-traumatic stress symptoms (PTSS) in response to medical trauma are understudied in inflammatory bowel disease (IBD). Two studies identify surgery, hospitalizations, and disease severity as risk factors. We aimed to document IBD-related patient experiences and how these relate to PTSS via a qualitative study. Adult patients with confirmed IBD recruited from two gastroenterology clinics underwent a semi-structured interview with a psychologist and completed the Post Traumatic Stress Disorder Symptom Scale for DSM5 (PSSI-5). Interviews were analyzed using an interpretive phenomenological approach. Themes and subthemes with representative quotations were documented based on thematic saturation. 16 participants, five met PSSI-5 criteria for PTSD. Five themes emerged: disease uncertainty, information exchange/quality, medical procedures, surgery, and coping. Patients with IBD may experience medical PTSS from several sources. Information, communication, and trust in clinicians is vital but may be sub-optimal. Both adaptive and maladaptive coping strategies are used to mitigate PTSS.

Comparison between handheld ultrasound and regional and whole-body dual energy x-ray absorptiometry (DXA) for body fat assessment.

OBJECTIVES: To determine the extent of agreement between a handheld ultrasound (US) attached to an android tablet and the reference method dual energy x-ray absorptiometry (DXA) for the measurement of adiposity. METHODS: A whole-body DXA scan and abdominal adipose tissue thickness measurements using a handheld US were obtained from 104 adults (63 females, 41 males). Body fat percent (BF%), total fat mass (kg), and trunk fat mass (kg) were obtained from DXA. Subcutaneous adipose tissue (SAT), superficial subcutaneous adipose tissue (SSAT), and deep subcutaneous adipose tissue (DSAT) thickness were obtained from US. Sex-specific total fat mass, trunk fat mass, and BF% estimates by US were compared with DXA. Spearman's correlations and Bland-Altman plots were used to assess agreement between the methods. RESULTS: US SAT correlated strongly with total fat mass for both females (rs = 0.74) and males (rs = 0.87) as did trunk fat mass (females, rs = 0.81; males, rs = 0.83); as did SSAT and DSAT (females: rs = 0.65 and rs = 0.66; males: rs = 0.63 and rs = 0.85, respectively, all p-values < 0.0001). Bland-Altman plots demonstrated strong agreement for total and trunk fat mass for both males and females. For BF%, acceptable limits of agreement were observed for males but not for females, substantial proportional bias as indicated by a negative slope was noted for BF% using SAT (r = -0.298, p = 0.0177). CONCLUSION: The handheld US and technique to analyze abdominal adipose tissue thickness showed strong agreement with DXA results and generated highly comparable estimates for total and trunk fat mass for both sexes.

Quantum Contagion: A Quantum-Like Approach for the Analysis of Social Contagion Dynamics with Heterogeneous Adoption Thresholds.

Modeling the information of social contagion processes has recently attracted a substantial amount of interest from researchers due to its wide applicability in network science, multi-agent-systems, information science, and marketing. Unlike in biological spreading, the existence of a reinforcement effect in social contagion necessitates considering the complexity of individuals in the systems. Although many studies acknowledged the heterogeneity of the individuals in their adoption of information, there are no studies that take into account the individuals' uncertainty during their adoption decision-making. This resulted in less than optimal modeling of social contagion dynamics in the existence of phase transition in the final adoption size versus transmission probability. We employed the Inverse Born Problem (IBP) to represent probabilistic entities as complex probability amplitudes in edge-based compartmental theory, and demonstrated that our novel approach performs better in the prediction of social contagion dynamics through extensive simulations on random regular networks.

IL-6 Inhibition in Critically Ill COVID-19 Patients Is Associated With Increased Secondary Infections.

Background: Anti-inflammatory therapies such as IL-6 inhibition have been proposed for COVID-19 in a vacuum of evidence-based treatment. However, abrogating the inflammatory response in infectious diseases may impair a desired host response and pre-dispose to secondary infections. Methods: We retrospectively reviewed the medical record of critically ill COVID-19 patients during an 8-week span and compared the prevalence of secondary infection and outcomes in patients who did and did not receive tocilizumab. Additionally, we included representative histopathologic post-mortem findings from several COVID-19 cases that underwent autopsy at our institution. Results: One hundred eleven patients were identified, of which 54 had received tocilizumab while 57 had not. Receiving tocilizumab was associated with a higher risk of secondary bacterial (48.1 vs. 28.1%; p = 0.029 and fungal (5.6 vs. 0%; p = 0.112) infections. Consistent with higher number of infections, patients who received tocilizumab had higher mortality (35.2 vs. 19.3%; p = 0.020). Seven cases underwent autopsy. In three cases who received tocilizumab, there was evidence of pneumonia on pathology. Of the four cases that had not been given tocilizumab, two showed evidence of aspiration pneumonia and two exhibited diffuse alveolar damage. Conclusions: Experimental therapies are currently being applied to COVID-19 outside of clinical trials. Anti-inflammatory therapies such as anti-IL-6 therapy have the potential to impair viral clearance, pre-dispose to secondary infection, and cause harm. We seek to raise physician awareness of these issues and highlight the need to better understand the immune response in COVID-19.

A stance data set on polarized conversations on Twitter about the efficacy of hydroxychloroquine as a treatment for COVID-19.

At the time of this study, the SARS-CoV-2 virus that caused the COVID-19 pandemic has spread significantly across the world. Considering the uncertainty about policies, health risks, financial difficulties, etc. the online media, especially the Twitter platform, is experiencing a high volume of activity related to this pandemic. Among the hot topics, the polarized debates about unconfirmed medicines for the treatment and prevention of the disease have attracted significant attention from online media users. In this work, we present a stance data set, COVID-CQ, of user-generated content on Twitter in the context of COVID-19. We investigated more than 14 thousand tweets and manually annotated the tweet initiators' opinions regarding the use of "chloroquine" and "hydroxychloroquine" for the treatment or prevention of COVID-19. To the best of our knowledge, COVID-CQ is the first data set of Twitter users' stances in the context of the COVID-19 pandemic, and the largest Twitter data set on users' stances towards a claim, in any domain. We have made this data set available to the research community via the Mendeley Data repository. We expect this data set to be useful for many research purposes, including stance detection, evolution and dynamics of opinions regarding this outbreak, and changes in opinions in response to the exogenous shocks such as policy decisions and events.

IL6 inhibition in critically ill COVID-19 patients is associated with increased secondary infections.

BACKGROUND: Anti-inflammatory therapies such as IL-6 inhibition have been proposed for COVID-19 in a vacuum of evidence-based treatment. However, abrogating the inflammatory response in infectious diseases may impair a desired host response and predispose to secondary infections. METHODS: We retrospectively reviewed the medical record of critically ill COVID-19 patients during an 8-week span and compared the prevalence of secondary infection and outcomes in patients who did and did not receive tocilizumab. Additionally, we included representative histopathologic post-mortem findings from several COVID-19 cases that underwent autopsy at our institution. RESULTS: 111 patients were identified, of which 54 had received tocilizumab while 57 had not. Receiving tocilizumab was associated with a higher risk of secondary bacterial (48.1% vs. 28.1%, p=0.029 and fungal (5.6% vs. 0%, p=0.112) infections. Consistent with higher number of infections, patients who received tocilizumab had higher mortality (35.2% vs. 19.3%, p=0.020). Seven cases underwent autopsy. In 3 cases who received tocilizumab, there was evidence of pneumonia on pathology. Of the 4 cases that had not been given tocilizumab, 2 showed evidence of aspiration pneumonia and 2 exhibited diffuse alveolar damage. CONCLUSIONS: Experimental therapies are currently being applied to COVID-19 outside of clinical trials. Anti-inflammatory therapies such as anti-IL-6 therapy have the potential to impair viral clearance, predispose to secondary infection, and cause harm. We seek to raise physician awareness of these issues and highlight the need to better understand the immune response in COVID-19.

Effects of taurocholic acid metabolism by gut bacteria: A controlled feeding trial in adult African American subjects at elevated risk for colorectal cancer.

Colorectal cancer (CRC) is the third leading cause of cancer and second leading cause of cancer death in the United States. Recent evidence has linked a high fat and animal protein diet and microbial metabolism of host bile acids as environmental risk factors for CRC development. We hypothesize that the primary bile salt taurocholic acid (TCA) is a key, diet-controlled metabolite whose use by bacteria yields a carcinogen and tumor-promoter, respectively. The work is motivated by our published data indicating hydrogen sulfide (H2S) and secondary bile acid production by colonic bacteria, serve as environmental insults contributing to CRC risk. The central aim of this study is to test whether a diet high in animal protein and saturated fat increases abundance of bacteria that generate H2S and pro-inflammatory secondary bile acids in African Americans (AAs) at high risk for CRC. Our prospective, randomized, crossover feeding trial will examine two microbial mechanisms by which an animal-based diet may support the growth of TCA metabolizing bacteria. Each subject will receive two diets in a crossover design- an animal-based diet, rich in taurine and saturated fat, and a plant-based diet, low in taurine and saturated fat. A mediation model will be used to determine the extent to which diet (independent variable) and mucosal markers of CRC risk and DNA damage (dependent variables) are explained by colonic bacteria and their functions (mediator variables). This research will generate novel information targeted to develop effective dietary interventions that may reduce the unequal CRC burden in AAs.

Diet Therapy for Inflammatory Bowel Diseases: A Call to the Dining Table.

There is vigorous interest among patients, caregivers, clinicians, and scientists to identify useful dietary interventions for inflammatory bowel diseases (IBD). Through the Cochrane Collaboration, we recently performed a systematic review and meta-analysis of dietary interventions for the induction or maintenance of remission in Crohn's disease (CD) and ulcerative colitis (UC) to assess the latest state of research. The current quality of evidence was formally graded to be low or very low for various methodological reasons, such as small sample sizes, heterogeneity among studies, and incomplete reporting. There are nonetheless emerging observational studies that progressively advance our knowledge and provide hope for a role of diet among traditional therapies to improve inflammation and symptoms. Further investments and concerted efforts in research are needed to significantly move the needle in identifying effective dietary therapies for IBD.

Development of collagenous colitis in inflammatory bowel disease: two case reports and a review of the literature.

The occurrence of collagenous colitis (CC) in patients with pre-existing inflammatory bowel diseases (IBD) is rare, with only seven cases reported in the past. Herein, we report two IBD cases who developed CC after successful treatment of their IBD with two different tumor necrosis factor (TNF)-α inhibitors, which have been previously reported to successfully treat refractory CC. This report highlights the need to do random biopsies of the colon for CC diagnosis in IBD patients with symptoms of diarrhea after complete mucosal healing. The report also reviews plausible mechanisms as to how CC may develop, including the role of multiple medications.

Food-related quality of life in patients with inflammatory bowel disease and irritable bowel syndrome.

BACKGROUND: Food-related quality of life (FRQoL) evaluates the impact of diet, eating behaviors, and food-related anxiety on a person's quality of life. This is the first study to evaluate FRQoL in inflammatory bowel disease (IBD) and irritable bowel syndrome (IBS), two illnesses where food and diet are of importance. METHODS: One hundred seventy-five participants (80 IBS, 95 IBD) participated in the study by completing measures evaluating FRQoL, psychological distress, and health-related quality of life. Primary analyses evaluated differences in FRQoL between IBD and IBS patients. Secondary analyses compared differences based on remission status, dietary use, and dietary consultation, as well as evaluated potential predictors of FRQoL. RESULTS: IBD patients in remission report the highest FRQoL (IBD-remission: 91.2 (26.5) vs. IBD-active: 67.7 (19.6) and IBS-active: 67.6 (18.3), p < .001). Using more dietary treatments is associated with decreased FRQoL for IBS (r = - 0.23, p < .05) and IBD patients (r = - 0.31, p < .01). IBS patients are more likely to use dietary treatments than IBD (IBS = 81% vs. IBD = 64%, p < .01), with self-directed diets being the most commonly used approach. Symptom severity is the strongest predictor of FRQoL in both groups (IBD: R2 = .27, p < .01; IBS: R2 = .23, p < .001). CONCLUSION: FRQoL is a unique construct for IBD and IBS patients that can be influenced by several clinical and dietary factors, including number of diets and type of diet used, depending on the diagnosis. Thus, FRQoL should be considered when working with both IBD and IBS patients.

Physical Inaccessibility of a Resistant Starch Shifts Mouse Gut Microbiota to Butyrogenic Firmicutes.

SCOPE: Resistant starch (RS) is utilized by Gram-negative Bacteroidetes through a starch utilization system (Sus), which requires physical attachment of the bacteria to the substrate. Gram-positive Firmicutes, which include butyrate producers, utilize RS by other mechanisms, such as amylosomes and secreted amylases/glucoamylases. It has been previously shown that fabricated RS [alginate-based starch-entrapped microspheres (SM)] increases butyrate in in vitro human fecal fermentation and was slow fermenting. It has been hypothesized that in vivo SM would disfavor Bacteroidetes and promote Firmicutes, leading to an increase in butyrate production. METHODS AND RESULTS: A C57BL/6J mouse model is used to test type 2 RS (RS2, raw potato) and SM for SCFAs and fecal microbial community structure. Feeding SM for 2 weeks results in 2.4 times higher mol% butyrate in the mouse distal gut than RS2. SM reduces relative abundance of Bacteroidetes and increases Firmicutes in fecal samples at the end of the 2-week feeding. This phylum-level taxonomic shift is not observed in animals fed RS2. CONCLUSION: Through an approach to understand bacterial requirements related to starch utilization, a designed fiber type favors butyrogenic Firmicutes bacteria and provides higher mol% butyrate in the distal gut with potential benefit as an anti-inflammatory agent and to improve gut barrier function.