Diet-induced dysbiosis of the intestinal microbiota and the effects on immunity and disease

Dietary resistant starch type 4-derived butyrate attenuates nuclear factor-kappa-B1 through modulation of histone H3 trimethylation at lysine 27

Indigestible resistant starches (RS) are substrates for gut-microbial metabolism and have been shown to attenuate intestinal inflammation but the supporting evidence is inconsistent and lacks mechanistic explanation. We have recently reported dietary RS type 4 (RS4) induced improvements in immunometabolic functions in humans and a concomitant increase in butyrogenic gut-bacteria. Since inflammation is a key component in metabolic diseases, here we investigated the effects of RS4-derived butyrate on the epigenetic repression of pro-inflammatory genes in vivo and in vitro. RS4-fed mice, compared to the control-diet group, had higher cecal butyrate and increased tri-methylation of lysine 27 on histone 3 (H3K27me3) in the promoter of nuclear factor-kappa-B1 (NFκB1) in the colon tissue. The H3K27me3-enrichment inversely correlated with the concentration dependent down-regulation of NFκB1 in sodium butyrate treated human colon epithelial cells. Two additional inflammatory genes were attenuated by sodium butyrate, but were not linked with H3K27me3 changes. This exploratory study presents a new opportunity for studying underlying H3K27me3 and other methylation modifying mechanisms linked to RS4 biological activity.

Environmental triggers in IBD: a review of progress and evidence

A number of environmental factors have been associated with the development of IBD. Alteration of the gut microbiota, or dysbiosis, is closely linked to initiation or progression of IBD, but whether dysbiosis is a primary or secondary event is unclear. Nevertheless, early-life events such as birth, breastfeeding and exposure to antibiotics, as well as later childhood events, are considered potential risk factors for IBD. Air pollution, a consequence of the progressive contamination of the environment by countless compounds, is another factor associated with IBD, as particulate matter or other components can alter the host's mucosal defences and trigger immune responses. Hypoxia associated with high altitude is also a factor under investigation as a potential new trigger of IBD flares. A key issue is how to translate environmental factors into mechanisms of IBD, and systems biology is increasingly recognized as a strategic tool to unravel the molecular alterations leading to IBD. Environmental factors add a substantial level of complexity to the understanding of IBD pathogenesis but also promote the fundamental notion that complex diseases such as IBD require complex therapies that go well beyond the current single-agent treatment approach. This Review describes the current conceptualization, evidence, progress and direction surrounding the association of environmental factors with IBD.

The rumen microbiome as a reservoir of antimicrobial resistance and pathogenicity genes is directly affected by diet in beef cattle

BACKGROUND

The emergence and spread of antimicrobial resistance is the most urgent current threat to human and animal health. An improved understanding of the abundance of antimicrobial resistance genes and genes associated with microbial colonisation and pathogenicity in the animal gut will have a major role in reducing the contribution of animal production to this problem. Here, the influence of diet on the ruminal resistome and abundance of pathogenicity genes was assessed in ruminal digesta samples taken from 50 antibiotic-free beef cattle, comprising four cattle breeds receiving two diets containing different proportions of concentrate.

RESULTS

Two hundred and four genes associated with antimicrobial resistance (AMR), colonisation, communication or pathogenicity functions were identified from 4966 metagenomic genes using KEGG identification. Both the diversity and abundance of these genes were higher in concentrate-fed animals. Chloramphenicol and microcin resistance genes were dominant in samples from forage-fed animals (P < 0.001), while aminoglycoside and streptomycin resistances were enriched in concentrate-fed animals. The concentrate-based diet also increased the relative abundance of Proteobacteria, which includes many animal and zoonotic pathogens. A high ratio of Proteobacteria to (Firmicutes + Bacteroidetes) was confirmed as a good indicator for rumen dysbiosis, with eight cases all from concentrate-fed animals. Finally, network analysis demonstrated that the resistance/pathogenicity genes are potentially useful as biomarkers for health risk assessment of the ruminal microbiome.

CONCLUSIONS

Diet has important effects on the complement of AMR genes in the rumen microbial community, with potential implications for human and animal health.

Preventing subclinical necrotic enteritis through Lactobacillus johnsonii BS15 by ameliorating lipid metabolism and intestinal microflora in broiler chickens

Increasing studies have focused on the beneficial effects of Lactobacillus johnsonii in certain diseases. Here, we studied the prevention ability of a probiotic strain, L. johnsonii BS15 on subclinical necrotic enteritis (SNE), and its underlying mechanism. 180 male Cobb 500 chicks were randomly allotted into three groups and administrated with BS15 (1 × 10⁶ cfu/g) or Man Rogosa Sharpe liquid medium throughout a 28-day experimental period. With the exception of the normal group, SNE infection was treated for the remaining experimental period after the chicks were fed with normal diet 14 days. Results showed that BS15 notably suppressed the SNE-induced loss of average daily gain and liver functional abnormality. Additionally, BS15 facilitated lipid metabolism of SNE boilers when the contents of peroxisome proliferator activated receptor γ and adipose triglyceride lipase in adipose tissue and serum high-density lipoprotein cholesterol decreased. BS15 also attenuated the hepatic lipid accumulation of stricken chicks by suppressing the genes expression of acetyl-CoA carboxylase, fatty acid synthase and sterol regulatory element binding protein-1c as well as stimulating the genes expression of peroxisome proliferator activated receptor α and carnitine palmitoyltransferase-1. Moreover, BS15 enhanced the development of SNE gut by improving the intestinal development and digestion as well as adjusting the gut microflora. Therefore, BS15 may provide a promising natural preventative strategy against SNE, which may be contributed to the amelioration of lipid metabolism and intestinal microflora.

Gut microbiota in early life and its influence on health and disease: A position paper by the Malaysian Working Group on Gastrointestinal Health

The role of gut microbiota in early life and its impact on gut health and subsequent diseases remain unclear. There is a lack of research and awareness in this area, especially in the Asia-Pacific region, including Malaysia. This paper reports the position of a Malaysian Working Group on some key issues surrounding gut microbiota in early life and its role in gut health and diseases, as well as experts' stand on probiotics and prebiotics. The group reached a consensus that certain factors, including elective caesarean; premature deliveries; complementary feeding; use of antibiotics, prebiotics and/or probiotics; and exposure to the external environmental, have an impact on gut microbiota in early life. However, as evidence is lacking, especially from the Asia-Pacific region, further studies are needed to understand how gut microbiota in early life affects subsequent diseases, including allergy, inflammatory bowel disease, obesity and infantile colic. Lastly, although beneficial in acute diarrhoeal disease and probably allergic eczema, probiotics (and/or prebiotics) should be used cautiously in other gut dysbiotic conditions until more data are available.

Rethinking the bile acid/gut microbiome axis in cancer

Dietary factors, probiotic agents, aging and antibiotics/medicines impact on gut microbiome composition leading to disturbances in localised microbial populations. The impact can be profound and underlies a plethora of human disorders, including the focus of this review; cancer. Compromised microbiome populations can alter bile acid signalling and produce distinct pathophysiological bile acid profiles. These in turn have been associated with cancer development and progression. Exposure to high levels of bile acids, combined with localised molecular/genome instability leads to the acquisition of bile mediated neoplastic alterations, generating apoptotic resistant proliferation phenotypes. However, in recent years, several studies have emerged advocating the therapeutic benefits of bile acid signalling in suppressing molecular and phenotypic hallmarks of cancer progression. These studies suggest that in some instances, bile acids may reduce cancer phenotypic effects, thereby limiting metastatic potential. In this review, we contextualise the current state of the art to propose that the bile acid/gut microbiome axis can influence cancer progression to the extent that classical in vitro cancer hallmarks of malignancy (cell invasion, cell migration, clonogenicity, and cell adhesion) are significantly reduced. We readily acknowledge the existence of a bile acid/gut microbiome axis in cancer initiation, however, in light of recent advances, we focus exclusively on the role of bile acids as potentially beneficial molecules in suppressing cancer progression. Finally, we theorise that suppressing aggressive malignant phenotypes through bile acid/gut microbiome axis modulation could uncover new and innovative disease management strategies for managing cancers in vulnerable cohorts.

Role of pregnane X-receptor in regulating bacterial translocation in chronic liver diseases

Bacterial translocation (BT) has been impeccably implicated as a driving factor in the pathogenesis of a spectrum of chronic liver diseases (CLD). Scientific evidence accumulated over the last four decades has implied that the disease pathologies in CLD and BT are connected as a loop in the gut-liver axis and exacerbate each other. Pregnane X receptor (PXR) is a ligand-activated transcription factor and nuclear receptor that is expressed ubiquitously along the gut-liver-axis. PXR has been intricately associated with the regulation of various mechanisms attributed in causing BT. The importance of PXR as the mechanistic linker molecule in the gut-liver axis and its role in regulating bacterial interactions with the host in CLD has not been explored. PubMed was used to perform an extensive literature search using the keywords PXR and bacterial translocation, PXR and chronic liver disease including cirrhosis. In an adequate expression state, PXR acts as a sensor for bile acid dysregulation and bacterial derived metabolites, and in response shapes the immune profile beneficial to the host. Activation of PXR could be therapeutic in CLD as it counter-regulates endotoxin mediated inflammation and maintains the integrity of intestinal epithelium. This review mainly focuses PXR function and its regulation in BT in the context of chronic liver diseases.

Gut Fermentation of Dietary Fibres: Physico-Chemistry of Plant Cell Walls and Implications for Health

The majority of dietary fibre (DF) originates from plant cell walls. Chemically, DF mostly comprise carbohydrate polymers, which resist hydrolysis by digestive enzymes in the mammalian small intestine, but can be fermented by large intestinal bacteria. One of the main benefits of DF relate to its fermentability, which affects microbial diversity and function within the gastro-intestinal tract (GIT), as well as the by-products of the fermentation process. Much work examining DF tends to focus on various purified ingredients, which have been extracted from plants. Increasingly, the validity of this is being questioned in terms of human nutrition, as there is evidence to suggest that it is the actual complexity of DF which affects the complexity of the GIT microbiota. Here, we review the literature comparing results of fermentation of purified DF substrates, with whole plant foods. There are strong indications that the more complex and varied the diet (and its ingredients), the more complex and varied the GIT microbiota is likely to be. Therefore, it is proposed that as the DF fermentability resulting from this complex microbial population has such profound effects on human health in relation to diet, it would be appropriate to include DF fermentability in its characterization-a functional approach of immediate relevance to nutrition.

Small Intestinal Bacterial Overgrowth and Irritable Bowel Syndrome: A Bridge between Functional Organic Dichotomy

The pathogenesis of irritable bowel syndrome (IBS), once thought to be largely psychogenic in origin, is now understood to be multifactorial. One of the reasons for this paradigm shift is the realization that gut dysbiosis, including small intestinal bacterial overgrowth (SIBO), causes IBS symptoms. Between 4% and 78% of patients with IBS and 1% and 40% of controls have SIBO; such wide variations in prevalence might result from population differences, IBS diagnostic criteria, and, most importantly, methods to diagnose SIBO. Although quantitative jejunal aspirate culture is considered the gold standard for the diagnosis of SIBO, noninvasive hydrogen breath tests have been popular. Although the glucose hydrogen breath test is highly specific, its sensitivity is low; in contrast, the early-peak criteria in the lactulose hydrogen breath test are highly nonspecific. Female gender, older age, diarrhea-predominant IBS, bloating and flatulence, proton pump inhibitor and narcotic intake, and low hemoglobin are associated with SIBO among IBS patients. Several therapeutic trials targeting gut microbes using antibiotics and probiotics have further demonstrated that not all symptoms in patients with IBS originate in the brain but rather in the gut, providing support for the micro-organic basis of IBS. A recent proof-of-concept study showing the high frequency of symptom improvement in patients with IBS with SIBO further supports this hypothesis.

Pig models on intestinal development and therapeutics

The gastrointestinal tract plays a vital role in nutrient supply, digestion, and absorption, and has a crucial impact on the entire organism. Much attention is being paid to utilize animal models to study the pathogenesis of gastrointestinal diseases in response to intestinal development and health. The piglet has a body size similar to that of the human and is an omnivorous animal with comparable anatomy, nutritional requirements, and digestive and associated inflammatory processes, and displays similarities to the human intestinal microbial ecosystem, which make piglets more appropriate as an animal model for human than other non-primate animals. Therefore, the objective of this review is to summarize key attributes of the piglet model with which to study human intestinal development and intestinal health through probing into the etiology of several gastrointestinal diseases, thus providing a theoretical and hopefully practical, basis for further studies on mammalian nutrition, health, and disease, and therapeutics. Given the comparable nutritional requirements and strikingly similar brain developmental patterns between young piglets and humans, the piglet has been used as an important translational model for studying neurodevelopmental outcomes influenced by pediatric nutrition. Because of similarities in anatomy and physiology between pigs and mankind, more emphasises are put on how to use the piglet model for human organ transplantation research.

Fusobacterium and colorectal cancer: causal factor or passenger? Results from a large colorectal cancer screening study

Colorectal cancer is a leading cause of morbidity and mortality worldwide in both men and women. The gut microbiome is increasingly recognized as having an important role in human health and disease. Fusobacterium has been identified in former studies as a leading gut bacterium associated with colorectal cancer, but it is still not clear if it plays an oncogenic role. In the current study, fecal samples were collected prior to bowel preparation from participants of screening colonoscopy in the German BliTz study. Using 16S rRNA gene analysis, we examined the presence and relative abundance of Fusobacterium in fecal samples from 500 participants, including 46, 113, 110 and 231 individuals with colorectal cancer, advanced adenomas, non-advanced adenomas and without any neoplasms, respectively. We found that the abundance of Fusobacterium in feces was strongly associated with the presence of colorectal cancer (P-value < 0.0001). This was confirmed by PCR at the species level for Fusobacterium nucleatum. However, no association was seen with the presence of advanced adenomas (P-value = 0.80) or non-advanced adenomas (P-value = 0.80), nor were there any associations observed with dietary or lifestyle habits. Although a causal role cannot be ruled out, our observations, based on fecal microbiome, support the hypothesis that Fusobacterium is a passenger that multiplies in the more favorable conditions caused by the malignant tumor rather than a causal factor in colorectal cancer development.

The Association between Modulating Inflammatory Cytokines and Constipation of Geriatrics in Iran

BACKGROUND

The effect of changes in intestinal microbiota on constipation is contraversial. Constipation is more prevalent in elderly. Therefore, the current study was designed to assess the role of modulating inflammatory cytokines in old age patients with constipation by evaluating the serum levels of tumor necrosis factor alpha (TNF-α), interleukin 1 (IL-l), and interleukin 6 (IL-6).

METHODS

This case-control study was done on 100 participants, aged 65 years or higher, with and without functional constipation according to ROME III criteria (50 participants in each group). Baseline demographic, clinical characteristics, and serum levels of TNF-α, IL-1, and IL-6 were compared between the case and control groups. Independent t test and Chi-square test were used for analysis of data.

RESULTS

Mean levels of TNF-α, IL-1, and IL-6 were (666.80 ± 101.40 pg/mL vs. 489.20 ± 53.68 pg/mL, p < 0.001), (435.96 ± 52.31 pg/mL vs. 296.44 ± 45.50 pg/mL, p < 0.001) and (438.18 ± 59.57 pg/mL vs. 290.14 ± 36.39 pg/mL, p < 0.001) in the case and control groups, respectively. A reverse correlation was found between the aging process and TNF-α (r = -0.26; p = 0.04), as well as IL-1 level (r = -0.41; p = 0.003) in the control group. A direct correlation was observed between the aging process and TNF-α (r = 0.40; p = 0.004) and IL-6 (r = 0.44; p = 0.002) levels in the case group.

CONCLUSION

This study showed a significant association between the serum level of modulating inflammatory cytokines and age-related constipation in Iranian subjects. It seems that the serum level of modulating inflammatory cytokines can be affected by diversity and abundance in the gut microbiota. The role of diversity in microbial population and their abundance in gut must be evaluated in further studies.

Defensive Mutualism Rescues NADPH Oxidase Inactivation in Gut Infection

NOX/DUOX family of NADPH oxidases are expressed in diverse tissues and are the primary enzymes for the generation of reactive oxygen species (ROS). The intestinal epithelium expresses NOX1, NOX4, and DUOX2, whose functions are not well understood. To address this, we generated mice with complete or epithelium-restricted deficiency in the obligatory NOX dimerization partner Cyba (p22(phox)). We discovered that NOX1 regulates DUOX2 expression in the intestinal epithelium, which magnified the epithelial ROS-deficiency. Unexpectedly, epithelial deficiency of Cyba resulted in protection from C. rodentium and L. monocytogenes infection. Microbiota analysis linked epithelial Cyba deficiency to an enrichment of H2O2-producing bacterial strains in the gut. In particular, elevated levels of lactobacilli physically displaced and attenuated C. rodentium virulence by H2O2-mediated suppression of the virulence-associated LEE pathogenicity island. This transmissible compensatory adaptation relied on environmental factors, an important consideration for prevention and therapy of enteric disease.

Immunomodulatory Properties of Coriolus versicolor: The Role of Polysaccharopeptide

Traditional uses of herbal medicine have depended mostly on anecdotal evidence for much of history. The increasing application of scientific rigor to the study some of these traditional therapies in recent years has revealed potent bioactivity, notably demonstrated by the 2015 Nobel Prize for the discovery of an antimalarial compound from traditional Chinese herbs. Given the recent successes of immunotherapy and checkpoint blockade, there is a renewed interest in identifying new drugs with immunomodulatory effects. As an estimated 45-60% of cancer patients worldwide are reported to use complementary alternative medicine alongside traditional therapy, this review will highlight the literature on the immunomodulatory effects of one of these compounds. We report on the induction of a largely pro-inflammatory cytokine profile by the polysaccharopeptide (PSP) isolated from the Coriolus versicolor (Yun zhi) mushroom, as well as its effects on various immune subsets, and the clinical data that have led to its widespread adoption as an adjunct cancer therapeutic in many Eastern cultures. Particular focus is given to the potential mechanisms underlying the bioactivity of PSP and reports of its ability to promote antitumor immunity by helping overcome tolerogenic tumor microenvironments.

A cross-sectional comparative study of gut bacterial community of Indian and Finnish children

The human gut microbiome plays a crucial role in the compositional development of gut microbiota. Though well documented in western pediatrics population, little is known about how various host conditions affect populations in different geographic locations such as the Indian subcontinent. Given the impact of distinct environmental conditions, our study assess the gut bacterial diversity of a small cohort of Indian and Finnish children and investigated the influence of FUT2 secretor status and birth mode on the gut microbiome of these populations. Using multiple profiling techniques, we show that the gut bacterial community structure in 13-14-year-old Indian (n = 47) and Finnish (n = 52) children differs significantly. Specifically, Finnish children possessed higher Blautia and Bifidobacterium, while genera Prevotella and Megasphaera were predominant in Indian children. Our study also demonstrates a strong influence of FUT2 and birth mode variants on specific gut bacterial taxa, influence of which was noticed to differ between the two populations under study.

Diet, Gut Microbiota, and Colorectal Cancer Prevention: A Review of Potential Mechanisms and Promising Targets for Future Research

Diet plays an important role in the development of colorectal cancer. Emerging data have implicated the gut microbiota in colorectal cancer. Diet is a major determinant for the gut microbial structure and function. Therefore, it has been hypothesized that alterations in gut microbes and their metabolites may contribute to the influence of diet on the development of colorectal cancer. We review several major dietary factors that have been linked to gut microbiota and colorectal cancer, including major dietary patterns, fiber, red meat and sulfur, and obesity. Most of the epidemiologic evidence derives from cross-sectional or short-term, highly controlled feeding studies that are limited in size. Therefore, high-quality large-scale prospective studies with dietary data collected over the life course and comprehensive gut microbial composition and function assessed well prior to neoplastic occurrence are critically needed to identify microbiome-based interventions that may complement or optimize current diet-based strategies for colorectal cancer prevention and management.

Diet, Gut Microbiome and Epigenetics: Emerging Links with Inflammatory Bowel Diseases and Prospects for Management and Prevention

Inflammatory bowel diseases (IBD) represent a growing public health concern due to increasing incidence worldwide. The current notion on the pathogenesis of IBD is that genetically susceptible individuals develop intolerance to dysregulated gut microflora (dysbiosis) and chronic inflammation develops as a result of environmental triggers. Among the environmental factors associated with IBD, diet plays an important role in modulating the gut microbiome, influencing epigenetic changes, and, therefore, could be applied as a therapeutic tool to improve the disease course. Nevertheless, the current dietary recommendations for disease prevention and management are scarce and have weak evidence. This review summarises the current knowledge on the complex interactions between diet, microbiome and epigenetics in IBD. Whereas an overabundance of calories and some macronutrients increase gut inflammation, several micronutrients have the potential to modulate it. Immunonutrition has emerged as a new concept putting forward the importance of vitamins such as vitamins A, C, E, and D, folic acid, beta carotene and trace elements such as zinc, selenium, manganese and iron. However, when assessed in clinical trials, specific micronutrients exerted a limited benefit. Beyond nutrients, an anti-inflammatory dietary pattern as a complex intervention approach has become popular in recent years. Hence, exclusive enteral nutrition in paediatric Crohn’s disease is the only nutritional intervention currently recommended as a first-line therapy. Other nutritional interventions or specific diets including the Specific Carbohydrate Diet (SCD), the low fermentable oligosaccharides, disaccharides, monosaccharides, and polyol (FODMAP) diet and, most recently, the Mediterranean diet have shown strong anti-inflammatory properties and show promise for improving disease symptoms. More work is required to evaluate the role of individual food compounds and complex nutritional interventions with the potential to decrease inflammation as a means of prevention and management of IBD.

The Role of Supplemental Complex Dietary Carbohydrates and Gut Microbiota in Promoting Cardiometabolic and Immunological Health in Obesity: Lessons from Healthy Non-Obese Individuals

Dietary supplementation with complex carbohydrates is known to alter the composition of gut microbiota, and optimal implementation of the use of these so called "prebiotics" could be of great potential in prevention and possibly treatment of obesity and associated cardiometabolic and inflammatory diseases via changes in the gut microbiota. An alternative to this "microbiocentric view" is the idea that health-promoting effects of certain complex carbohydrates reside in the host, and could secondarily affect the diversity and abundance of gut microbiota. To circumvent this potential interpretational problem, we aimed at providing an overview about whether and how dietary supplementation of different complex carbohydrates changes the gut microbiome in healthy non-obese individuals. We then reviewed whether the reported changes in gut bacterial members found to be established by complex carbohydrates would benefit or harm the cardiometabolic and immunological health of the host taking into account the alterations in the microbiome composition and abundance known to be associated with obesity and its associated disorders. By combining these research areas, we aimed to give a better insight into the potential of (foods containing) complex carbohydrates in the treatment and prevention of above-mentioned diseases. We conclude that supplemental complex carbohydrates that increase Bifidobacteria and Lactobacilli, without increasing the deleterious Bacteroides, are most likely promoting cardiometabolic and immunological health in obese subjects. Because certain complex carbohydrates also affect the host's immunity directly, it is likely that host-microbiome interactions in determination of health and disease characteristics are indeed bidirectional. Overall, this review article shows that whereas it is relatively clear in which direction supplemental fermentable carbohydrates can alter the gut microbiome, the relevance of these changes regarding health remains controversial. Future research should take into account the different causes of obesity and its adverse health conditions, which in turn have drastic effects on the microbiome balance.

Pregnancy, Proteinuria, Plant-Based Supplemented Diets and Focal Segmental Glomerulosclerosis: A Report on Three Cases and Critical Appraisal of the Literature

Chronic kidney disease (CKD) is increasingly recognized in pregnant patients. Three characteristics are associated with a risk of preterm delivery or small for gestational age babies; kidney function reduction, hypertension, and proteinuria. In pregnancy, the anti-proteinuric agents (ACE-angiotensin converting enzyme-inhibitors or ARBS -angiotensin receptor blockers) have to be discontinued for their potential teratogenicity, and there is no validated approach to control proteinuria. Furthermore, proteinuria usually increases as an effect of therapeutic changes and pregnancy-induced hyperfiltration. Based on a favourable effect of low-protein diets on proteinuria and advanced CKD, our group developed a moderately protein-restricted vegan-vegetarian diet tsupplemented with ketoacids and aminoacids for pregnant patients. This report describes the results obtained in three pregnant patients with normal renal function, nephrotic or sub-nephrotic proteinuria, and biopsy proven diagnosis of focal segmental glomerulosclerosis, a renal lesion in which hyperfiltration is considered of pivotal importance (case 1: GFR (glomerular filtration rate): 103 mL/min; proteinuria 2.1 g/day; albumin 3.2 g/dL; case 2: GFR 86 mL/min, proteinuria 3.03 g/day, albumin 3.4 g/dL; case 3: GFR 142 mL/min, proteinuria 6.3 g/day, albumin 3.23 g/dL). The moderately restricted diet allowed a stabilisation of proteinuria in two cases and a decrease in one. No significant changes in serum creatinine and serum albumin were observed. The three babies were born at term (38 weeks + 3 days, female, weight 3180 g-62th centile; 38 weeks + 2 days, female, weight 3300 g-75th centile; male, 38 weeks + 1 day; 2770 g-8th centile), thus reassuring us of the safety of the diet. In summary, based on these three cases studies and a review of the literature, we suggest that a moderately protein-restricted, supplemented, plant-based diet might contribute to controlling proteinuria in pregnant CKD women with focal segmental glomerulosclerosis. However further studies are warranted to confirm the potential value of such a treatment strategy.

Human Gut Microbiota: Toward an Ecology of Disease

Composed of trillions of individual microbes, the human gut microbiota has adapted to the uniquely diverse environments found in the human intestine. Quickly responding to the variances in the ingested food, the microbiota interacts with the host via reciprocal biochemical signaling to coordinate the exchange of nutrients and proper immune function. Host and microbiota function as a unit which guards its balance against invasion by potential pathogens and which undergoes natural selection. Disturbance of the microbiota composition, or dysbiosis, is often associated with human disease, indicating that, while there seems to be no unique optimal composition of the gut microbiota, a balanced community is crucial for human health. Emerging knowledge of the ecology of the microbiota-host synergy will have an impact on how we implement antibiotic treatment in therapeutics and prophylaxis and how we will consider alternative strategies of global remodeling of the microbiota such as fecal transplants. Here we examine the microbiota-human host relationship from the perspective of the microbial community dynamics.

Linking rhizosphere microbiome composition of wild and domesticated Phaseolus vulgaris to genotypic and root phenotypic traits

Plant domestication was a pivotal accomplishment in human history, but also led to a reduction in genetic diversity of crop species compared to their wild ancestors. How this reduced genetic diversity affected plant-microbe interactions belowground is largely unknown. Here, we investigated the genetic relatedness, root phenotypic traits and rhizobacterial community composition of modern and wild accessions of common bean (Phaseolus vulgaris) grown in agricultural soil from the highlands of Colombia, one of the centers of common bean diversification. Diversity Array Technology-based genotyping and phenotyping of local common bean accessions showed significant genetic and root architectural differences between wild and modern accessions, with a higher specific root length for the wild accessions. Canonical Correspondence Analysis indicated that the divergence in rhizobacterial community composition between wild and modern bean accessions is associated with differences in specific root length. Along the bean genotypic trajectory, going from wild to modern, we observed a gradual decrease in relative abundance of Bacteroidetes, mainly Chitinophagaceae and Cytophagaceae, and an increase in relative abundance of Actinobacteria and Proteobacteria, in particular Nocardioidaceae and Rhizobiaceae, respectively. Collectively, these results establish a link between common bean domestication, specific root morphological traits and rhizobacterial community assembly.

Dietary Behaviors in Psoriasis: Patient-Reported Outcomes from a U.S. National Survey

INTRODUCTION

Psoriasis patients demonstrate high interest in the role of diet on their skin condition. However, data are lacking to describe dietary interventions among psoriasis patients and associated outcomes. This study aims to identify common dietary habits, interventions and perceptions among patients with psoriasis, and to examine patient-reported skin outcomes in response to these interventions.

METHODS

We administered a 61-question survey to the National Psoriasis Foundation membership asking psoriasis patients about dietary habits, modifications, skin responses, and perceptions.

RESULTS

A total of 1206 psoriasis patients responded to the survey. Compared to age- and sex-matched controls, psoriasis patients consumed significantly less sugar, whole grain fiber, dairy, and calcium (p < 0.001), while consuming more fruits, vegetables, and legumes (p < 0.01). Eighty-six percent of respondents reported use of a dietary modification. The percentage of patients reporting skin improvement was greatest after reducing alcohol (53.8%), gluten (53.4%), nightshades (52.1%), and after adding fish oil/omega-3 (44.6%), vegetables (42.5%), and oral vitamin D (41%). Specific diets with the most patients reporting a favorable skin response were Pagano (72.2%), vegan (70%), and Paleolithic (68.9%). Additionally, 41.8% of psoriasis respondents reported that a motivation for attempting dietary changes was to improve overall health.

CONCLUSION

This national survey is among the first to report the dietary behaviors of patients with psoriasis. The data provided from this large cohort may benefit patients and clinicians as they discuss the role of diet in managing both psoriasis and associated cardiometabolic comorbidities.

The ecological community of commensal, symbiotic, and pathogenic gastrointestinal microorganisms - an appraisal

The human gastrointestinal tract is inhabited by a vast population of bacteria, numbering ~100 trillion. These microorganisms have been shown to play a significant role in digestion, metabolism, and the immune system. The aim of this study was to review and discuss how the human body interacts with its gut microbiome and in turn the effects that the microorganisms have on its host, overall resulting in a true mutualistic relationship.

Inulin with different degrees of polymerization modulates composition of intestinal microbiota in mice

The study aimed to analyze the global influences of dietary inulin with different degrees of polymerization (DP) on intestinal microbial communities. Six-week-old male C57BL/6J mice were treated with fructo-oligosaccharides and inulin for 6 weeks. Fecal samples were obtained at time point 0 and 6th week. 16S rRNA sequence analysis was used to measure intestinal microbiota performed on the Illumina MiSeq platform. Influences of dietary inulin on intestinal microbiota were more complex effects than bifidogenic effects, relative abundance of butyrate-producing bacteria increased after interventions. Akkermansia muciniphila, belonging to mucin-degrading species, became a dominant species in Verrucomicrobia phylum after treatment with fructo-oligosaccharides and inulin. Modulation effects of intestinal microbiota were positively correlated with DP. Lower DP interventions exhibited better effects than higher DP treatment on stimulation of probiotics. We hypothesized that Akkermansia muciniphila played an important role on maintaining balance between mucin and short chain fatty acids.

Predictors of response to a low-FODMAP diet in patients with functional gastrointestinal disorders and lactose or fructose intolerance

BACKGROUND

Diets low in fermentable sugars (low-FODMAP diets) are increasingly adopted by patients with functional gastrointestinal disorders (FGID), but outcome predictors are unclear.

AIM

To identify factors predictive of an efficacious response to a low-FODMAP diet in FGID patients with fructose or lactose intolerance thereby gaining insights into underlying mechanisms.

METHODS

Fructose and lactose breath tests were performed in FGID patients to determine intolerance (positive symptom score) and malabsorption (increased hydrogen or methane concentrations). Patients with fructose or lactose intolerance consumed a low-FODMAP diet and global adequate symptom relief was assessed after 6-8 weeks and correlated with pre-diet clinical symptoms and breath test results.

RESULTS

A total of 81% of 584 patients completing the low-FODMAP diet achieved adequate relief, without significant differences between FGID subgroups or types of intolerance. Univariate analysis yielded predictive factors in fructose intolerance (chronic diarrhoea and pruritus, peak methane concentrations and fullness during breath tests) and lactose intolerance (peak hydrogen and methane concentrations and flatulence during breath tests). Using multivariate analysis, symptom relief was independently and positively predicted in fructose intolerance by chronic diarrhoea [odds ratio (95% confidence intervals): 2.62 (1.31-5.27), P = 0.007] and peak breath methane concentrations [1.53 (1.02-2.29), P = 0.042], and negatively predicted by chronic nausea [0.33 (0.16-0.67), P = 0.002]. No independent predictive factors emerged for lactose intolerance.

CONCLUSIONS

Adequate global symptom relief was achieved with a low-FODMAP diet in a large majority of functional gastrointestinal disorders patients with fructose or lactose intolerance. Independent predictors of a satisfactory dietary outcome were only seen in fructose intolerant patients, and were indicative of changes in intestinal host or microbiome metabolism.

A randomized trial to determine the impact of a digestion resistant starch composition on the gut microbiome in older and mid-age adults

BACKGROUND

The elderly often have a diet lacking resistant starch (RS) which is thought to lead to gut microbiome dysbiosis that may result in deterioration of gut colonocytes.

OBJECTIVE

The primary objective was to assess if elderly (ELD; ≥ 70 years age) had microbiome dysbiosis compared to mid-age (MID; 30-50 years age) adults and then determine the impact of daily consumption of MSPrebiotic^® (a RS) or placebo over 3 months on gut microbiome composition. Secondary objectives included assessment of stool short-chain fatty acids (SCFA) and inflammatory markers in ELD and MID Canadian adults.

DESIGN

This was a prospective, placebo controlled, randomized, double-blinded study. Stool was collected at enrollment and 6, 10 and 14 weeks after randomization to placebo or MSPrebiotic^®. Microbiome analysis was done using 16S rRNA sequencing of DNA extracted from stool. SCFA analysis of stool was performed using gas chromatography.

RESULTS

There were 42 ELD and 42 MID participants randomized to either placebo or MSPrebiotic^® who completed the study. There was significantly higher abundance of Proteobacteria (Escherichia coli/Shigella) in ELD compared to MID at enrollment (p < 0.001) that was not observed after 12 weeks of MSPrebiotic^® consumption. There was a significant increase in Bifidobacterium in both ELD and MID compared to placebo (p = 0.047 and 0.006, respectively). There was a small but significant increase in the stool SCFA butyrate levels in the ELD on MSPrebiotic^® versus placebo.

CONCLUSIONS

The study data demonstrated that MSPrebiotic^® meets the criteria of a prebiotic and can stimulate an increased abundance of endogenous Bifidobacteria in both ELD and MID without additional probiotic supplementation. MSPrebiotic^® consumption also eliminated the dysbiosis of gut Proteobacteria observed in ELD at baseline.

CLINICAL TRIAL REGISTRY NUMBER

NCT01977183 listed on NIH website: ClinicalTrials.gov. The full trial protocol is available on request from the corresponding author.

NUCLEOTIDE SEQUENCE ACCESSION NUMBERS

The 16S rRNA sequencing data and metadata generated in this study have been submitted to the NCBI Sequence Read Archive (SRA: http://www.ncbi.nlm.nih.gov/bioproject/381931).

Evidence for a causal relationship between low vitamin D, high BMI, and pediatric-onset MS

OBJECTIVE

To utilize Mendelian randomization to estimate the causal association between low serum vitamin D concentrations, increased body mass index (BMI), and pediatric-onset multiple sclerosis (MS) using genetic risk scores (GRS).

METHODS

We constructed an instrumental variable for vitamin D (vitD GRS) by computing a GRS for 3 genetic variants associated with levels of 25(OH)D in serum using the estimated effect of each risk variant. A BMI GRS was also created that incorporates the cumulative effect of 97 variants associated with BMI. Participants included non-Hispanic white individuals recruited from over 15 sites across the United States (n = 394 cases, 10,875 controls) and Sweden (n = 175 cases, 5,376 controls; total n = 16,820).

RESULTS

Meta-analysis findings demonstrated that a vitD GRS associated with increasing levels of 25(OH)D in serum decreased the odds of pediatric-onset MS (odds ratio [OR] 0.72, 95% confidence interval [CI] 0.55, 0.94; p = 0.02) after controlling for sex, genetic ancestry, HLA-DRB1*15:01, and over 100 non-human leukocyte antigen MS risk variants. A significant association between BMI GRS and pediatric disease onset was also demonstrated (OR 1.17, 95% CI 1.05, 1.30; p = 0.01) after adjusting for covariates. Estimates for each GRS were unchanged when considered together in a multivariable model.

CONCLUSIONS

We provide evidence supporting independent and causal effects of decreased vitamin D levels and increased BMI on susceptibility to pediatric-onset MS.

The role of diet in multiple sclerosis: A review

Multiple sclerosis (MS) is a multifactorial, inflammatory, and neurodegenerative disease of the central nervous system, where environmental factors interact with genetic susceptibility. The role of diet on MS has not been comprehensively elucidated; therefore, through an extensive search of relevant literature, this review reports the most significant evidence regarding nutrition as a possible co-factor influencing the inflammatory cascade by acting on both its molecular pathways and gut microbiota. Since nutritional status and dietary habits in MS patients have not been extensively reported, the lack of a scientific-based consensus on dietary recommendation in MS could encourage many patients to experiment alternative dietetic regimens, increasing the risk of malnutrition. This work investigates the health implications of an unbalanced diet in MS, and collects recent findings on nutrients of great interest among MS patients and physicians. The aim of this review is to elucidate the role of an accurate nutritional counseling in MS to move toward a multidisciplinary management of the disease and to encourage future studies demonstrating the role of a healthy diet on the onset and course of MS.

The Role of Intestinal Alkaline Phosphatase in Inflammatory Disorders of Gastrointestinal Tract

Over the past few years, the role of intestinal alkaline phosphatase (IAP) as a crucial mucosal defence factor essential for maintaining gut homeostasis has been established. IAP is an important apical brush border enzyme expressed throughout the gastrointestinal tract and secreted both into the intestinal lumen and into the bloodstream. IAP exerts its effects through dephosphorylation of proinflammatory molecules including lipopolysaccharide (LPS), flagellin, and adenosine triphosphate (ATP) released from cells during stressful events. Diminished activity of IAP could increase the risk of disease through changes in the microbiome, intestinal inflammation, and intestinal permeability. Exogenous IAP exerts a protective effect against intestinal and systemic inflammation in a variety of diseases and represents a potential therapeutic agent in diseases driven by gut barrier dysfunction such as IBD. The intestinal protective mechanisms are impaired in IBD patients due to lower synthesis and activity of endogenous IAP, but the pathomechanism of this enzyme deficiency remains unclear. IAP has been safely administered to humans and the human recombinant form of IAP has been developed. This review was designed to provide an update in recent research on the involvement of IAP in intestinal inflammatory processes with focus on IBD in experimental animal models and human patients.

Causal Effect of Genetic Variants Associated With Body Mass Index on Multiple Sclerosis Susceptibility

Multiple sclerosis (MS) is an autoimmune disease with both genetic and environmental risk factors. Recent studies indicate that childhood and adolescent obesity double the risk of MS, but this association may reflect unmeasured confounders rather than causal effects of obesity. We used separate-sample Mendelian randomization to estimate the causal effect of body mass index (BMI) on susceptibility to MS. Using data from non-Hispanic white members of the Kaiser Permanente Medical Care Plan of Northern California (KPNC) (2006-2014; 1,104 cases of MS and 10,536 controls) and a replication data set from Sweden (the Epidemiological Investigation of MS (EIMS) and the Genes and Environment in MS (GEMS) studies, 2005-2013; 5,133 MS cases and 4,718 controls), we constructed a weighted genetic risk score using 97 variants previously established to predict BMI. Results were adjusted for birth year, sex, education, smoking status, ancestry, and genetic predictors of MS. Estimates in KPNC and Swedish data sets suggested that higher genetically induced BMI predicted greater susceptibility to MS (odds ratio = 1.13, 95% confidence interval: 1.04, 1.22 for the KPNC sample; odds ratio = 1.09, 95% confidence interval: 1.03, 1.15 for the Swedish sample). Although the mechanism remains unclear, to our knowledge, these findings support a causal effect of increased BMI on susceptibility to MS for the first time, and they suggest a role for inflammatory pathways that characterize both obesity and the MS disease process.

Gut Microbiota in a Rat Oral Sensitization Model: Effect of a Cocoa-Enriched Diet

Increasing evidence is emerging suggesting a relation between dietary compounds, microbiota, and the susceptibility to allergic diseases, particularly food allergy. Cocoa, a source of antioxidant polyphenols, has shown effects on gut microbiota and the ability to promote tolerance in an oral sensitization model. Taking these facts into consideration, the aim of the present study was to establish the influence of an oral sensitization model, both alone and together with a cocoa-enriched diet, on gut microbiota. Lewis rats were orally sensitized and fed with either a standard or 10% cocoa diet. Faecal microbiota was analysed through metagenomics study. Intestinal IgA concentration was also determined. Oral sensitization produced few changes in intestinal microbiota, but in those rats fed a cocoa diet significant modifications appeared. Decreased bacteria from the Firmicutes and Proteobacteria phyla and a higher percentage of bacteria belonging to the Tenericutes and Cyanobacteria phyla were observed. In conclusion, a cocoa diet is able to modify the microbiota bacterial pattern in orally sensitized animals. As cocoa inhibits the synthesis of specific antibodies and also intestinal IgA, those changes in microbiota pattern, particularly those of the Proteobacteria phylum, might be partially responsible for the tolerogenic effect of cocoa.

The advancement of probiotics research and its application in fish farming industries

Fish are always susceptible to a variety of lethal diseases caused by different types of bacterial, fungal, viral and parasitic agents. The unscientific management practises such as, over feeding, high stock densities and destructive fishing techniques increase the probability of disease symptoms in aquaculture industries. According to Food and Agriculture Association (FAO), each and every year several countries such as China, India, Norway, Indonesia, etc. face a huge loss in aquaculture production due to mainly bacterial and viral diseases. The use of antibiotics is a common practise in fish farming sectors to control the disease outbreak. However, the antibiotics are not long term friend because it creates selective pressure for emergence of drug resistant bacteria. Probiotics are live microorganisms that confer several beneficial effects to host (enhances immunity, helps in digestion, protects from pathogens, improves water quality, promotes growth and reproduction) and can be used as an alternative of antibiotics. In recent year, a wide range of bacteria have reported as potential probiotics candidates in fish farming sectors, however, Lactobacillus sp. and Bacillus sp. gain special attention due to their high antagonistic activities, extracellular enzyme production and availability. In this present review, we have summarized the recent advancement in aquaculture probiotics research and its impact on fish health, nutrition, immunity, reproduction and water quality.

Support for the microgenderome invites enquiry into sex differences

The microgenderome defines the interaction between microbiota, sex hormones and the immune system. Our recent research inferred support for the microgenderome by showing sex differences in microbiota-symptom associations in a clinical sample of patients with myalgic encephalomyelitis / chronic fatigue syndrome (ME/CFS). This addendum expands upon the sex-specific pattern of associations that were observed. Interpretations are hypothesized in relation to genera versus species-level analyses and D-lactate theory. Evidence of sex-differences invites future research to consider sex comparisons in microbial function even when microbial abundance is statistically similar. Pairing assessment of clinical symptoms with microbial culture, DNA sequencing and metabolomics methods will help advance our current understandings of the role of the microbiome in health and disease.

Immunology of Gut-Bone Signaling

In recent years a link between the gastrointestinal tract and bone health has started to gain significant attention. Dysbiosis of the intestinal microbiota has been linked to the pathology of a number of diseases which are associated with bone loss. In addition modulation of the intestinal microbiota with probiotic bacteria has revealed to have both beneficial local and systemic effects. In the present chapter, we discuss the intestinal and bone immune systems, explore how intestinal disease affects the immune system, and examine how these pathologic changes could adversely impact bone health.

Feeding the microbiota-gut-brain axis: diet, microbiome, and neuropsychiatry

The microbial population residing within the human gut represents one of the most densely populated microbial niche in the human body with growing evidence showing it playing a key role in the regulation of behavior and brain function. The bidirectional communication between the gut microbiota and the brain, the microbiota-gut-brain axis, occurs through various pathways including the vagus nerve, the immune system, neuroendocrine pathways, and bacteria-derived metabolites. This axis has been shown to influence neurotransmission and the behavior that are often associated with neuropsychiatric conditions. Therefore, research targeting the modulation of this gut microbiota as a novel therapy for the treatment of various neuropsychiatric conditions is gaining interest. Numerous factors have been highlighted to influence gut microbiota composition, including genetics, health status, mode of birth, and environment. However, it is diet composition and nutritional status that has repeatedly been shown to be one of the most critical modifiable factors regulating the gut microbiota at different time points across the lifespan and under various health conditions. Thus the microbiota is poised to play a key role in nutritional interventions for maintaining brain health.

Role of Vitamin D in the Hygiene Hypothesis: The Interplay between Vitamin D, Vitamin D Receptors, Gut Microbiota, and Immune Response

The hygiene hypothesis postulates that higher levels of cleanliness and improper exposure to microorganisms early in childhood could disturb the intestinal microbiome resulting in abnormal immune responses. Recently, more attention has been put on how a lack of sun exposure and consequently vitamin D deficiency could lead to less immune tolerance and aberrant immune responses. Moreover, vitamin D receptor (VDR) function has been positioned to be a critical aspect of immune response and gut homeostasis. Therefore, this review focuses on the role that the interaction between vitamin D, VDR function, and gut microbiome might have on autoimmune diseases in the context of the hygiene hypothesis. Literature shows that there is a high correlation between vitamin D deficiency, VDR dysfunction, gut microbiota composition, and autoimmune diseases. The biologically active form of vitamin D, 1,25(OH)₂D₃, serves as the primary ligand for VDRs, which have been shown to play a fundamental role in reducing autoimmune disease symptoms. Although the biological functions of VDR, the effects of its genetic variants, and the effects of epigenetic profiles in its promoter region are largely unknown in humans, studies in murine models are increasingly demonstrating that VDRs play a crucial role in attenuating autoimmune disease symptoms by regulating autophagy and the production of antimicrobial peptides, such cathelicidin and β-defensin, which are responsible for modifying the intestinal microbiota to a healthier composition. Remarkably, evidence shows that hormonal compounds and byproducts of the microbiota such as secondary bile acids might also activate VDR. Therefore, understanding the interaction between VDR and gut microbiota is of the utmost importance toward understanding the rise in autoimmune diseases in Western countries. We have gained insights on how the VDR functions affects inflammation, autophagy, and microbiota composition that could lead to the development of pathogenesis of autoimmune diseases, while confirming the role vitamin D and VDRs have in the context of hygiene hypothesis.

A Possible Role of Intestinal Microbiota in the Pathogenesis of Ankylosing Spondylitis

Ankylosing spondylitis (AS) is a chronic inflammatory disease primarily affecting the sacroiliac joints and the spine, for which the pathogenesis is thought to be a result of the combination of host genetic factors and environmental triggers. However, the precise factors that determine one’s susceptibility to AS remain to be unraveled. With 100 trillion bacteria residing in the mammalian gut having established a symbiotic relation with their host influencing many aspects of host metabolism, physiology, and immunity, a growing body of evidence suggests that intestinal microbiota may play an important role in AS. Several mechanisms have been suggested to explain the potential role of the microbiome in the etiology of AS, such as alterations of intestinal permeability, stimulation of immune responses, and molecular mimicry. In this review, the existing evidence for the involvement of the microbiome in AS pathogenesis was discussed and the potential of intestinal microbiome-targeting strategies in the prevention and treatment of AS was evaluated.

Dietary Changes Impact the Gut Microbe Composition in Overweight and Obese Men with Prostate Cancer Undergoing Radical Prostatectomy

BACKGROUND

Diet and obesity influence prostate cancer risk and progression-effects that may be mediated through the gut microbiome.

OBJECTIVE

Our aim was to explore relationships among diet, gut microbes, and Gleason sum in overweight and obese prostate cancer patients enrolled in a presurgical weight-loss trial.

DESIGN

Randomized controlled trial (NCT01886677) secondary analysis.

PARTICIPANTS/SETTING

In 2013-2014, 40 prostate cancer patients in the southeastern United States were randomized and allocated equally to weight-loss and wait-list control arms while they awaited prostatectomy; stool samples were collected on a subset of 22 patients.

INTERVENTION

Registered dietitian nutritionists and exercise physiologists provided semi-weekly in-person and telephone-based guidance on calorie-restricted diets and exercise to promote an approximate weight loss of 0.91 kg/wk.

MAIN OUTCOME MEASURES

Baseline and follow-up 24-hour dietary recalls were conducted and analyzed (using the Automated Self-Administered 24-hour dietary recall system; National Cancer Institute, Bethesda, MD) for macronutrients, micronutrients, and food groups. Microbiome analysis targeting the V4 region of the 16S ribosomal RNA gene was performed on fecal samples. Biopsy Gleason sum data were accessed from diagnostic pathology reports.

STATISTICAL ANALYSES PERFORMED

Associations between dietary factors and operational taxonomic units were determined by β-diversity analysis. Wilcoxon signed rank, and Mann-Whitney U testing assessed within- and between-arm differences. Associations between Gleason sum and operational taxonomic units, and diet and operational taxonomic units, were analyzed using Spearman correlations.

RESULTS

At baseline, Proteobacteria (median 0.06, interquartile range 0.01 to 0.16) were abundant, with four orders positively associated with Gleason sum. Gleason sum was associated with Clostridium (ρ=.579; P=0.005) and Blautia (ρ=-0.425, P=0.049). Increased red meat consumption from baseline was associated with Prevotella (ρ=-.497; P=0.018) and Blautia (ρ=.422; P=0.039). Men who increased poultry intake had decreased Clostridiales abundance (P=0.009).

CONCLUSIONS

This hypothesis-generating study provides a starting point for investigating the relationships between the fecal microbiome, diet, and prostate cancer. Adequately powered studies are required to further explore and validate these findings.

Vendor effects on murine gut microbiota influence experimental abdominal sepsis

BACKGROUND

Experimental animal models are indispensable components of preclinical sepsis research. Reproducible results highly rely on defined and invariant baseline conditions. Our hypothesis was that the murine gut microbiota varies among different distributors of laboratory animals and that these variations influence the phenotype of abdominal sepsis derived from a bacterial inoculum model (intraperitoneal stool injection).

MATERIALS AND METHODS

Male C57BL/6 mice (8-wk old) purchased from Charles River (CR), Janvier (J), and Harlan (H) were sacrificed, and the bacterial composition of feces was analyzed using CHROMagar orientation medium. Stool was injected intraperitoneally into CR mice, followed by clinical observation and gene expression analysis. Experiments were repeated 16 mo later under the same conditions.

RESULTS

Stool analysis revealed profound intervendor differences in bacterial composition, mainly regarding Staphylococcus aureus and Bacillus licheniformis. Mice challenged with CR as well as H feces developed significantly higher severity of disease and died within the observation period, whereas stool from J mice did not induce any of these symptoms. Real-time polymerase chain reaction revealed corresponding results with significant upregulation of proinflammatory cytokines and vascular leakage-related mediators in CR and H injected animals. Sixteen months later, the bacterial fecal composition had significantly shifted. The differences in clinical phenotype of sepsis after intraperitoneal stool injection had vanished.

CONCLUSIONS

We are the first to demonstrate vendor and time effects on the murine fecal microbiota influencing sepsis models of intraabdominal stool contamination. The intestinal microbiota must be defined and standardized when designing and interpreting past and future studies using murine abdominal sepsis models.

Onset of Ulcerative Colitis during a Low-Carbohydrate Weight-Loss Diet and Treatment with a Plant-Based Diet: A Case Report

Overweight and obesity are global health concerns. Various effective weight-loss diets have been developed, including the Atkins diet. The Atkins diet is known as an extreme low-carbohydrate diet. This diet reduces body weight and has gained widespread popularity. However, the metabolite profiles of such a diet have been shown to be detrimental to colonic health. Therefore, a concern for the long-term health effects of this diet exists. We encountered a case in which ulcerative colitis developed while the patient was following the Atkins diet.A man, 172 cm in height and weighing 72 kg, at age 36 years followed a low-carbohydrate weight-loss diet. His weight decreased to 66 kg as desired. Thereafter he noticed bloody stool. Colonoscopy revealed diffuse inflammation limited to the rectum, and he was diagnosed with ulcerative colitis. He underwent an educational hospitalization for ulcerative colitis. A plant-based/semivegetarian diet was provided during hospitalization. Bloody stool disappeared during hospitalization and he achieved remission without medication for inflammatory bowel disease.This case indicates that an onset of ulcerative colitis can be an adverse event to a low-carbohydrate weight-loss diet.

Duodenal endoluminal barrier sleeve alters gut microbiota of ZDF rats

BACKGROUND/OBJECTIVES

The combination of energy dense diets and reduced energy expenditure in modern society has escalated the prevalence of obesity and obesity-related comorbidities. Among these disease states, type-2 diabetics (T2D) are disproportionately associated with obesity, suggesting a shared etiology. In conjunction with defects in hormonal and inflammatory states, obesity and T2D are also characterized by dysbiosis.

METHODS

We have recently described the beneficial effects of duodenal nutrient exclusion, as induced by the duodenal endoluminal sleeve (DES); including body weight loss, prevented fat mass accumulation, and improved glucose tolerance in the ZDF rat, a rodent model of obesity and type-2 diabetes (T2D). To assess the relative role of DES on hindgut microbiota in the context of these metabolic changes, we analyzed cecal samples from rats implanted with a duodenal endoluminal sleeve (DES), or a sham control of this procedure. A group of pair-fed (pf) sham controls was also included to account for changes induced by reduced body weight and food intake.

RESULTS

Analysis of hindgut microbiota following DES in the ZDF rat elucidated discrete changes in several microbial populations including a reduction in Paraprevotella family members of the Clostridiales order along with an increase in Akkermansia muciniphila and species of the Allobaculum and Bifidobacterium genera.

CONCLUSIONS

Altogether, these observations suggest that like Roux-en Y gastric bypass (RYGB) and Metformin, regulation of gut microbiota may be a contributing factor to the therapeutic effects of DES.

Duodenal endoluminal barrier sleeve alters gut microbiota of ZDF rats

BACKGROUND/OBJECTIVES

The combination of energy dense diets and reduced energy expenditure in modern society has escalated the prevalence of obesity and obesity-related comorbidities. Among these disease states, type-2 diabetics (T2D) are disproportionately associated with obesity, suggesting a shared etiology. In conjunction with defects in hormonal and inflammatory states, obesity and T2D are also characterized by dysbiosis.

METHODS

We have recently described the beneficial effects of duodenal nutrient exclusion, as induced by the duodenal endoluminal sleeve (DES); including body weight loss, prevented fat mass accumulation, and improved glucose tolerance in the ZDF rat, a rodent model of obesity and type-2 diabetes (T2D). To assess the relative role of DES on hindgut microbiota in the context of these metabolic changes, we analyzed cecal samples from rats implanted with a duodenal endoluminal sleeve (DES), or a sham control of this procedure. A group of pair-fed (pf) sham controls was also included to account for changes induced by reduced body weight and food intake.

RESULTS

Analysis of hindgut microbiota following DES in the ZDF rat elucidated discrete changes in several microbial populations including a reduction in Paraprevotella family members of the Clostridiales order along with an increase in Akkermansia muciniphila and species of the Allobaculum and Bifidobacterium genera.

CONCLUSIONS

Altogether, these observations suggest that like Roux-en Y gastric bypass (RYGB) and Metformin, regulation of gut microbiota may be a contributing factor to the therapeutic effects of DES.

Light/Dark Shifting Promotes Alcohol-Induced Colon Carcinogenesis: Possible Role of Intestinal Inflammatory Milieu and Microbiota

Background: Colorectal cancer (CRC) is associated with the modern lifestyle. Chronic alcohol consumption—a frequent habit of majority of modern societies—increases the risk of CRC. Our group showed that chronic alcohol consumption increases polyposis in a mouse mode of CRC. Here we assess the effect of circadian disruption—another modern life style habit—in promoting alcohol-associated CRC. Method: TS4Cre × adenomatous polyposis coli (APC)^lox468 mice underwent (a) an alcohol-containing diet while maintained on a normal 12 h light:12 h dark cycle; or (b) an alcohol-containing diet in conjunction with circadian disruption by once-weekly 12 h phase reversals of the light:dark (LD) cycle. Mice were sacrificed after eight weeks of full alcohol and/or LD shift to collect intestine samples. Tumor number, size, and histologic grades were compared between animal groups. Mast cell protease 2 (MCP2) and 6 (MCP6) histology score were analyzed and compared. Stool collected at baseline and after four weeks of experimental manipulations was used for microbiota analysis. Results: The combination of alcohol and LD shifting accelerated intestinal polyposis, with a significant increase in polyp size, and caused advanced neoplasia. Consistent with a pathogenic role of stromal tryptase-positive mast cells in colon carcinogenesis, the ratio of mMCP6 (stromal)/mMCP2 (intraepithelial) mast cells increased upon LD shifting. Baseline microbiota was similar between groups, and experimental manipulations resulted in a significant difference in the microbiota composition between groups. Conclusions: Circadian disruption by Light:dark shifting exacerbates alcohol-induced polyposis and CRC. Effect of circadian disruption could, at least partly, be mediated by promoting a pro-tumorigenic inflammatory milieu via changes in microbiota.

Glycoside Hydrolases across Environmental Microbial Communities

Across many environments microbial glycoside hydrolases support the enzymatic processing of carbohydrates, a critical function in many ecosystems. Little is known about how the microbial composition of a community and the potential for carbohydrate processing relate to each other. Here, using 1,934 metagenomic datasets, we linked changes in community composition to variation of potential for carbohydrate processing across environments. We were able to show that each ecosystem-type displays a specific potential for carbohydrate utilization. Most of this potential was associated with just 77 bacterial genera. The GH content in bacterial genera is best described by their taxonomic affiliation. Across metagenomes, fluctuations of the microbial community structure and GH potential for carbohydrate utilization were correlated. Our analysis reveals that both deterministic and stochastic processes contribute to the assembly of complex microbial communities.