Effect of Bran Particle Size on Gut Microbiota Community Structure and Function

Gut microbiome composition and function are increasingly known to be linked to host health. Many factors control the gut microbiota, including mode of birth, host health status, genetics, and sanitary conditions, but diet has been one of the most-studied factors as a tool to modulate gut microbiota. Dietary fibers that act as prebiotics escape human digestion and reach the colon, where they become available to the microbes as a source of energy. Gut microbes produce various metabolites that are beneficial to the host health. Among those metabolites thought to be most important are the short-chain fatty acids (SCFAs) acetate, propionate, and butyrate. There is high interest in studying prebiotics that increase the production of these SCFAs as they are thought have many health benefits, such as being anti-inflammatory and anti-carcinogenic. Gut commensal preferences for these prebiotics depend on their chemical and physical properties. Other factors like the quantities of prebiotics and in what combinations they are consumed also influence gut microbial populations. There have been many studies conducted to test the effect of chemical differences amongst prebiotics on the gut microbiota, however, research studying the physical properties of dietary fiber and its effect on gut microbes is relatively scarce. To test the hypothesis that physical size of cereal bran particles influences their fermentation by microbiota, we tested different size fractions of wheat and maize bran in in vitro fermentation by fecal microbial communities. Microbes showed size-dependent bran preferences in the case of both wheat and maize bran, both in terms of community structure and metabolites production. For wheat bran, we tested 180-300, 300-500, 500-800, 850-1000 and \u3e1700 m fractions with fecal microbiota from three healthy donors pooled in equal amounts by weight. We saw clear, size-dependent metabolic outcomes (SCFAs production) which were accompanied by divergent microbial community structures as analyzed by 16S rRNA sequencing. We further also linked these responses to size-dependent chemical differences of wheat bran fractions. In the second study with maize bran, we tested 180-250, 250-300, 300-500 and 500-850 m size fractions. Like in the case of wheat bran fractions, maize bran also showed size-dependent microbial community structure and metabolic outputs. Overall, this work demonstrated that bran particle size has potential as a tool for fine-tuning the gut microbiota, which in turn can alter metabolite production and have potential benefits to host health

Dual-purpose Injectable Doxorubicin Conjugated Alginate Gel Containing Polycaprolactone Microparticles for Anti-Cancer and Anti-Inflammatory Therapy

In situ gel formulations have been widely reported as a carrier for sustained release delivery systems due to certain advantages such as targeted drug delivery, minimal invasiveness and potent therapeutic activity. Herein, in situ gel system for sustained release of doxorubicin and ibuprofen for anti-cancer and anti-inflammatory activity is reported. Doxorubicin-conjugated alginate (dox-alg) gel was prepared using EDC-NHS chemistry and loaded with ibuprofen encapsulated polycaprolactone (PCL) microparticles (dox-alg composite). PCL microparticles were prepared by a solvent evaporation method (size 50 - 100µm). The gel was characterized using SEM, FTIR, XRD and TGA analysis. Dox-alg composite gel showed good syringeability and gel formation properties. Burst release was observed for both drugs within 24 h followed by sustained release till day 21. Doxorubicin released from composite showed considerable cytotoxic effect. Cell uptake was confirmed by confocal microscopy using MDA-MB-231 cells. Anti-inflammatory activity of ibuprofen released from composite gel was compared with the free drug. An injection of dox-alg composite gel in the tissue would fill the void created after tumor removal surgery, prevent the resuscitation of remnant cancerous cells and reduce inflammation. Thus, the dox-alg composite gel could be a potential agent for the dual anti-cancer and anti-inflammatory therapy

Maize Bran Particle Size Governs the Community Composition and Metabolic Output of Human Gut Microbiota in in vitro Fermentations

Differences in the chemical and physical properties of dietary fibers are increasingly known to exert effects on their fermentation by gut microbiota. Here, we demonstrate that maize bran particle size fractions show metabolic output and microbial community differences similar to those we previously observed for wheat brans. As for wheat brans, maize bran particles varied in starch and protein content and in sugar composition with respect to size. We fermented maize bran particles varying in size in vitro with human fecal microbiota as inocula, measuring their metabolic fate [i.e., short-chain fatty acids (SCFAs)] and resulting community structure (via 16S rRNA gene amplicon sequencing). Metabolically, acetate, propionate and butyrate productions were size-dependent. 16S rRNA sequencing revealed that the size-dependent SCFA production was linked to divergent microbial community structures, which exerted effects at fine taxonomic resolution (the genus and species level). These results further suggest that the physical properties of bran particles, such as size, are important variables governing microbial community compositional and metabolic responses

Subtle Variations in Dietary-Fiber Fine Structure Differentially Influence the Composition and Metabolic Function of Gut Microbiota

Diet, especially with respect to consumption of dietary fibers, is well recognized as one of the most important factors shaping the colonic microbiota composition. Accordingly, many studies have been conducted to explore dietary fiber types that could predictably manipulate the colonic microbiota for improved health. However, the majority of these studies underappreciate the vastness of fiber structures in terms of their microbial utilization and omit detailed carbohydrate structural analysis. In some cases, this causes conflicting results to arise between studies using (theoretically) the same fibers. In this investigation, by performing in vitro fecal fermentation studies using bran arabinoxylans obtained from different classes of wheat, we showed that even subtle changes in the structure of a dietary fiber result in divergent microbial communities and metabolic outputs. This underscores the need for much higher structural resolution in studies investigating interactions of dietary fibers with gut microbiota, both in vitro and in vivo . ABSTRACT The chemical structures of soluble fiber carbohydrates vary from source to source due to numerous possible linkage configurations among monomers. However, it has not been elucidated whether subtle structural variations might impact soluble fiber fermentation by colonic microbiota. In this study, we tested the hypothesis that subtle structural variations in a soluble polysaccharide govern the community structure and metabolic output of fermenting microbiota. We performed in vitro fecal fermentation studies using arabinoxylans (AXs) from different classes of wheat (hard red spring [AX HRS ], hard red winter [AX HRW ], and spring red winter [AX SRW ]) with identical initial microbiota. Carbohydrate analyses revealed that AX SRW was characterized by a significantly shorter backbone and increased branching compared with those of the hard varieties. Amplicon sequencing demonstrated that fermentation of AX SRW resulted in a distinct community structure of significantly higher richness and evenness than those of hard-AX-fermenting cultures. AX SRW favored OTUs within Bacteroides , whereas AX HRW and AX HRS favored Prevotella . Accordingly, metabolic output varied between hard and soft varieties; higher propionate production was observed with AX SRW and higher butyrate and acetate with AX HRW and AX HRS . This study showed that subtle changes in the structure of a dietary fiber may strongly influence the composition and function of colonic microbiota, further suggesting that physiological functions of dietary fibers are highly structure dependent. Thus, studies focusing on interactions among dietary fiber, gut microbiota, and health outcomes should better characterize the structures of the carbohydrates employed. IMPORTANCE Diet, especially with respect to consumption of dietary fibers, is well recognized as one of the most important factors shaping the colonic microbiota composition. Accordingly, many studies have been conducted to explore dietary fiber types that could predictably manipulate the colonic microbiota for improved health. However, the majority of these studies underappreciate the vastness of fiber structures in terms of their microbial utilization and omit detailed carbohydrate structural analysis. In some cases, this causes conflicting results to arise between studies using (theoretically) the same fibers. In this investigation, by performing in vitro fecal fermentation studies using bran arabinoxylans obtained from different classes of wheat, we showed that even subtle changes in the structure of a dietary fiber result in divergent microbial communities and metabolic outputs. This underscores the need for much higher structural resolution in studies investigating interactions of dietary fibers with gut microbiota, both in vitro and in vivo

Fecal Microbiota Responses to Bran Particles Are Specific to Cereal Type and In Vitro Digestion Methods That Mimic Upper Gastrointestinal Tract Passage

Although in vitro studies to identify interactions between food components and the colonic microbiota employ distinct methods to mimic upper gastrointestinal (GI) tract digestion, the effects of differences in protocols on fermentation have not been rigorously addressed. Here, we compared two widely used upper GI tract digestion methods on four different cereal brans in fermentations by fecal microbiota to test the hypotheses that (1) different methods are varyingly efficient in removing accessible starches and proteins from dietary components and (2) these result in cereal-specific differences in fermentation by fecal microbiota. Our results supported both hypotheses, in that the methods differed significantly in bran starch and protein retention and that the effects were cereal-specific. Furthermore, these differences impacted fermentation by the fecal microbiota of healthy donors, altering both short-chain fatty acid production and microbial community composition. These data suggest that digestion methods should be standardized across laboratories for in vitro fiber fermentation studies

Divergent short-chain fatty acid production and succession of colonic microbiota arise in fermentation of variously-sized wheat bran fractions

Abstract Though the physical structuring of insoluble dietary fiber sources may strongly impact their processing by microbiota in the colon, relatively little mechanistic information exists to explain how these aspects affect microbial fiber fermentation. Here, we hypothesized that wheat bran fractions varying in size would be fermented differently by gut microbiota, which would lead to size-dependent differences in metabolic fate (as short-chain fatty acids; SCFAs) and community structure. To test this hypothesis, we performed an in vitro fermentation assay in which wheat bran particles from a single source were separated by sieving into five size fractions and inoculated with fecal microbiota from three healthy donors. SCFA production, measured by gas chromatography, uncovered size fraction-dependent relationships between total SCFAs produced as well as the molar ratios of acetate, propionate, and butyrate. 16S rRNA sequencing revealed that these size-dependent metabolic outcomes were accompanied by the development of divergent microbial community structures. We further linked these distinct results to subtle, size-dependent differences in chemical composition. These results suggest that physical context can drive differences in microbiota composition and function, that fiber-microbiota interaction studies should consider size as a variable, and that manipulating the size of insoluble fiber-containing particles might be used to control gut microbiome composition and metabolic output

Improvement in Glucose Regulation Using a Digital Tracker and Continuous Glucose Monitoring in Healthy Adults and Those with Type 2 Diabetes

Introduction While continuous glucose monitoring (CGM) has been shown to decrease both hyper- and hypoglycemia in insulin-treated diabetes, its value in non-insulin-treated type 2 diabetes (T2D) and prediabetes is unclear. Studies examining the reduction in hyperglycemia with the use of CGM in non-insulin-treated T2D are limited. Methods We investigated the potential benefit of CGM combined with a mobile app that links each individual's glucose tracing to meal composition, heart rate, and physical activity in a cohort of 1022 individuals, ranging from nondiabetic to non-insulin-treated T2D, spanning a wide range of demographic, geographic, and socioeconomic characteristics. The primary endpoint was the change in time in range (TIR), defined as 54-140 mg/dL for healthy and prediabetes, and 54-180 mg/dL for T2D, from the beginning to end of a 10-day period of use of the Freestyle Libre CGM. Logged food intake, physical activity, continuous glucose, and heart rate data were captured by a smartphone-based app that continuously provided feedback to participants, overlaying daily glucose patterns with activity and food intake, including macronutrient breakdown, glycemic load (GL), and glycemic index (GI). Results A total of 665 participants meeting eligibility and data requirements were included in the final analysis. Among self-reported nondiabetic participants, CGM identified glucose excursions in the diabetic range among 15% of healthy and 36% of those with prediabetes. In the group as a whole, TIR improved significantly (p < 0.001). Among the 51.4% of participants who improved, TIR increased by an average of 6.4% (p < 0.001). Of those with poor baseline TIR, defined as TIR below comparable A1c thresholds for T2D and prediabetes, 58.3% of T2D and 91.7% of healthy/prediabetes participants improved their TIR by an average of 22.7% and 23.2%, respectively. Predictors of improved response included no prior diagnosis of T2D and lower BMI. Conclusions These results indicate that 10-day use of CGM as a part of multimodal data collection, with synthesis and feedback to participants provided by a mobile health app, can significantly reduce hyperglycemia in non-insulin-treated individuals, including those with early stages of glucose dysregulation

Comparative genomics of the genus Roseburia reveals divergent biosynthetic pathways that may influence colonic competition among species

Roseburia species are important denizens of the human gut microbiome that ferment complex polysaccharides to butyrate as a terminal fermentation product, which influences human physiology and serves as an energy source for colonocytes. Previous comparative genomics analyses of the genus Roseburia have examined polysaccharide degradation genes. Here, we characterize the core and pangenomes of the genus Roseburia with respect to central carbon and energy metabolism, as well as biosynthesis of amino acids and B vitamins using orthology-based methods, uncovering significant differences among species in their biosynthetic capacities. Variation in gene content among Roseburia species and strains was most significant for cofactor biosynthesis. Unlike all other species of Roseburia that we analysed, Roseburia inulinivorans strains lacked biosynthetic genes for riboflavin or pantothenate but possessed folate biosynthesis genes. Differences in gene content for B vitamin synthesis were matched with differences in putative salvage and synthesis strategies among species. For example, we observed extended biotin salvage capabilities in R. intestinalis strains, which further suggest that B vitamin acquisition strategies may impact fitness in the gut ecosystem. As differences in the functional potential to synthesize components of biomass (e.g. amino acids, vitamins) can drive interspecies interactions, variation in auxotrophies of the Roseburia spp. genomes may influence in vivo gut ecology. This study serves to advance our understanding of the potential metabolic interactions that influence the ecology of Roseburia spp. and, ultimately, may provide a basis for rational strategies to manipulate the abundances of these species

Outcome of Stem Cell Transplantation in HTLV-1-Associated North American Adult T-Cell Leukemia/Lymphoma.

Adult T-cell leukemia/lymphoma (ATLL) remains challenging to treat and has dismal outcome. Allogeneic stem-cell transplantation (allo-SCT) has promising results, but data remain scarce. In this single-center retrospective analysis of 100 patients with ATLL from north America (67 acute, 22 lymphomatous), 17 underwent allo-SCT and 5 autologous SCT (ASCT), with a median follow-up of 65&nbsp;months. Post-transplant 3-years relapse incidence (RI) and non-relapse mortality (NRM) were 51% and 37%, respectively, and 3-year progression-free survival (PFS) and overall survival (OS) were 31% and 35%, respectively. ASCT 1-year RI was 80% compared to 30% in allo-SCT (p = 0.03). After adjusting for immortal-time bias, allo-SCT had significantly improved OS (HR = 0.4, p = 0.01). In exploratory multivariate analysis, patients achieving first complete response and Karnofsky score ≥ 90 had significantly better outcomes, as did Black patients, compared to Hispanics, who had worse outcome. In transplanted patients, 14 died within 2&nbsp;years, 4 of which ASCT recipients. Our data are the largest ATLL transplant cohort presented to date outside of Japan and Europe. We show that allo-SCT, but not ASCT, is a valid option in select ATLL patients, and can induce long term survival, with 40% of patients alive after more than 5&nbsp;years