Fisetin modulates the gut microbiota alongside biomarkers of senescence and inflammation in a DSS-induced murine model of colitis

Colitis, a subtype of inflammatory bowel disease (IBD), is a multifactorial disorder characterized by chronic inflammation of the colon. Among various experimental models used in the study of IBD, the chemical colitogenic dextran sulfate sodium (DSS) is most commonly employed to induce colitis in vivo. In the search for new therapeutic strategies, Fisetin, a flavonoid found in many fruits and vegetables, has recently garnered attention for its senolytic properties. Female mice were administered 2.5% DSS in sterile drinking water and were subsequently treated with Fisetin or vehicle by oral gavage. DSS significantly upregulated beta-galactosidase activity in colonic proteins, while Fisetin remarkably inhibited its activity to baseline levels. Particularly, qPCR revealed that the senescence and inflammation markers Vimentin and Ptgs2 were elevated by DSS exposure with Fisetin treatment inhibiting the expression of p53, Bcl2, Cxcl1, and Mcp1, indicating that the treatment reduced senescent cell burden in the DSS targeted intestine. Alongside, senescence and inflammation associated miRNAs miR-149-5p, miR-96-5p, miR-34a-5p, and miR-30e-5p were significantly inhibited by DSS exposure and restored by Fisetin treatment, revealing novel targets for the treatment of IBDs. Metagenomics was implemented to assess impacts on the microbiota, with DSS increasing the prevalence of bacteria in the phyla Bacteroidetes. Meanwhile, Fisetin restored gut health through increased abundance of Akkermansia muciniphila, which is negatively correlated with senescence and inflammation. Our study suggests that Fisetin mitigates DSS-induced colitis by targeting senescence and inflammation and restoring beneficial bacteria in the gut indicating its potential as a therapeutic intervention for IBDs.

Dynamics of serum exosome microRNA profile altered by chemically induced estropause and rescued by estrogen therapy in female mice

The decline in the ovarian reserve leads to menopause and reduced serum estrogens. MicroRNAs are small non-coding RNAs, which can regulate gene expression and be secreted by cells and trafficked in serum via exosomes. Serum miRNAs regulate tissue function and disease development. Therefore, the aim of this study was to identify miRNA profiles in serum exosomes of mice induced to estropause and treated with 17β-estradiol (E2). Female mice were divided into three groups including control (CTL), injected with 4-Vinylcyclohexene diepoxide (VCD), and injected with VCD plus E2 (VCD + E2). Estropause was confirmed by acyclicity and a significant reduction in the number of ovarian follicles (p < 0.05). Body mass gain during estropause was higher in VCD and VCD + E2 compared to CTL females (p = 0.02). Sequencing of miRNAs was performed from exosomes extracted from serum, and 402 miRNAs were detected. Eight miRNAs were differentially regulated between CTL and VCD groups, seven miRNAs regulated between CTL and VCD + E2 groups, and ten miRNAs regulated between VCD and VCD + E2 groups. Only miR-200a-3p and miR-200b-3p were up-regulated in both serum exosomes and ovarian tissue in both VCD groups, suggesting that these exosomal miRNAs could be associated with ovarian activity. In the hepatic tissue, only miR-370-3p (p = 0.02) was up-regulated in the VCD + E2 group, as observed in serum. Our results suggest that VCD-induced estropause and E2 replacement have an impact on the profile of serum exosomal miRNAs. The miR-200 family was increased in serum exosomes and ovarian tissue and may be a candidate biomarker of ovarian function.

Association of Common Foods with Inflammation and Mortality: Analysis from a Large Prospective Cohort Study

Some dietary patterns are associated with inflammation, while others lower inflammation and improve health. However, many people cannot follow a complete, healthy diet. Therefore, this study's aim was to identify specific foods associated chronic inflammation and mortality. The study used Multi-Ethnic Study of Atherosclerosis (MESA) research materials from the NHLBI Biologic Specimen and Data Repository Information Coordinating Center. Three plant-based and three animal-based MESA food categories were chosen based on perceived availability in the western diet. The assessed food categories were avocado, ham, sausage, eggs, greens, and broccoli. Inflammatory markers assessed were interleukin-6 (IL-6), fibrinogen antigen, C-reactive protein, D-Dimer, interleukin-2, matrix metalloproteinase 3, necrosis factor-a soluble receptors, oxidized LDL (oxLDL), and total homocysteine. The primary outcome was the multivariable association of foods and inflammatory markers with all-cause mortality. All inflammatory makers, except oxLDL, were associated with mortality in univariate analysis. The effect was largest with IL-6 and D-dimer. The category of broccoli had the most consistent association in univariate analyses with lower inflammation and lower mortality odds. Low and high broccoli consumption versus no consumption were associated with lower mortality odds in the multivariable models with IL-6 and D-dimer. Consumption of the MESA-defined food category "broccoli" (i.e., broccoli, cabbage, cauliflower, brussels sprouts, sauerkraut, and kimchee) was associated with lower inflammation and lower mortality odds. These findings should be validated in randomized controlled trials testing a "food is medicine" approach to identify which, if any, of these foods may have potential as an herbal therapeutic for chronic inflammation.

Abnormalities in microbiota/butyrate/FFAR3 signaling in aging gut impair brain function

Aging-related abnormalities in gut microbiota are associated with cognitive decline, depression, and anxiety, but underlying mechanisms remain unstudied. Here, our study demonstrated that transplanting old gut microbiota to young mice induced inflammation in the gut and brain coupled with cognitive decline, depression, and anxiety. We observed diminished mucin formation and increased gut permeability ("leaky gut") with a reduction in beneficial metabolites like butyrate because of decline in butyrate-producing bacteria in the aged gut microbiota. This led to suppressed expression of butyrate receptors, free fatty acid receptors 2 and 3 (FFAR2/3). Administering butyrate alleviated inflammation, restored mucin expression and gut barriers, and corrected brain dysfunction. Furthermore, young mice with intestine-specific loss of FFAR2/3 exhibited gut and brain abnormalities akin to those in older mice. Our results demonstrate that reduced butyrate-producing bacteria in aged gut microbiota result in low butyrate levels and reduced FFAR2/3 signaling, leading to suppressed mucin formation that increases gut permeability, inflammation, and brain abnormalities. These findings underscore the significance of butyrate-FFAR2/3 agonism as a potential strategy to mitigate aged gut microbiota-induced detrimental effects on gut and brain health in older adults.

Oro-Respiratory Dysbiosis and Its Modulatory Effect on Lung Mucosal Toxicity during Exposure or Co-Exposure to Carbon Nanotubes and Cigarette Smoke

The oro-respiratory microbiome is impacted by inhalable exposures such as smoking and has been associated with respiratory health conditions. However, the effect of emerging toxicants, particularly engineered nanoparticles, alone or in co-exposure with smoking, is poorly understood. Here, we investigated the impact of sub-chronic exposure to carbon nanotube (CNT) particles, cigarette smoke extract (CSE), and their combination. The oral, nasal, and lung microbiomes were characterized using 16S rRNA-based metagenomics. The exposures caused the following shifts in lung microbiota: CNT led to a change from Proteobacteria and Bacteroidetes to Firmicutes and Tenericutes; CSE caused a shift from Proteobacteria to Bacteroidetes; and co-exposure (CNT+CSE) had a mixed effect, maintaining higher numbers of Bacteroidetes (due to the CNT effect) and Tenericutes (due to the CSE effect) compared to the control group. Oral microbiome analysis revealed an abundance of the following genera: Acinetobacter (CNT), Staphylococcus, Aggregatibacter, Allobaculum, and Streptococcus (CSE), and Alkalibacterium (CNT+CSE). These proinflammatory microbial shifts correlated with changes in the relative expression of lung mucosal homeostasis/defense proteins, viz., aquaporin 1 (AQP-1), surfactant protein A (SP-A), mucin 5b (MUC5B), and IgA. Microbiota depletion reversed these perturbations, albeit to a varying extent, confirming the modulatory role of oro-respiratory dysbiosis in lung mucosal toxicity. This is the first demonstration of specific oro-respiratory microbiome constituents as potential modifiers of toxicant effects in exposed lungs.

Geroprotective potential of microbiome modulators in the Caenorhabditis elegans model

Aging is associated with cellular and physiological changes, which significantly reduce the quality of life and increase the risk for disease. Geroprotectors improve lifespan and slow the progression of detrimental aging-related changes such as immune system senescence, mitochondrial dysfunction, and dysregulated nutrient sensing and metabolism. Emerging evidence suggests that gut microbiota dysbiosis is a hallmark of aging-related diseases and microbiome modulators, such as probiotics (live bacteria) or postbiotics (non-viable bacteria/bacterial byproducts) may be promising geroprotectors. However, because they are strain-specific, the geroprotective effects of probiotics and postbiotics remain poorly understood and understudied. Drosophila melanogaster, Caenorhabditis elegans, and rodents are well-validated preclinical models for studying lifespan and the role of probiotics and/or postbiotics, but each have their limitations, including cost and their translation to human aging biology. C. elegans is an excellent model for large-scale screening to determine the geroprotective potential of drugs or probiotics/postbiotics due to its short lifecycle, easy maintenance, low cost, and homology to humans. The purpose of this article is to review the geroprotective effects of microbiome modulators and their future scope, using C. elegans as a model. The proposed geroprotective mechanisms of these probiotics and postbiotics include delaying immune system senescence, preventing or reducing mitochondrial dysfunction, and regulating food intake (dietary restriction) and metabolism. More studies are warranted to understand the geroprotective potential of probiotics and postbiotics, as well as other microbiome modulators, like prebiotics and fermented foods, and use them to develop effective therapeutics to extend lifespan and reduce the risk of debilitating aging-related diseases.

Intestinal FFA2 promotes obesity by altering food intake in Western diet-fed mice

Short-chain fatty acids (SCFAs) are key nutrients that play a diverse set of roles in physiological function, including regulating metabolic homeostasis. Generated through the fermentation of dietary fibers in the distal colon by the gut microbiome, SCFAs and their effects are partially mediated by their cognate receptors, including free fatty acid receptor 2 (FFA2). FFA2 is highly expressed in the intestinal epithelial cells, where its putative functions are controversial, with numerous in vivo studies relying on global knockout mouse models to characterize intestine-specific roles of the receptor. Here, we used the Villin-Cre mouse line to generate a novel, intestine-specific knockout mouse model for FFA2 (Vil-FFA2) to investigate receptor function within the intestine. Because dietary changes are known to affect the composition of the gut microbiome, and can thereby alter SCFA production, we performed an obesogenic challenge on male Vil-FFA2 mice and their littermate controls (FFA2-floxed, FFA2fl/fl) to identify physiological changes on a high-fat, high-sugar 'Western diet' (WD) compared to a low-fat control diet (CD). We found that the WD-fed Vil-FFA2 mice were transiently protected from the obesogenic effects of the WD and had lower fat mass and improved glucose homeostasis compared to the WD-fed FFA2fl/fl control group during the first half of the study. Additionally, major differences in respiratory exchange ratio and energy expenditure were observed in the WD-fed Vil-FFA2 mice, and food intake was found to be significantly reduced at multiple points in the study. Taken together, this study uncovers a novel role of intestinal FFA2 in mediating the development of obesity.

New horizon to the world of gut microbiome: seeds germination

The second brain of humans has been known as the microbiome. The microbiome is a dynamic network composed of commensal bacteria, archaea, viruses, and fungi colonized in the human gastrointestinal tract. They play a vital role in human health by metabolizing components, maturation of the immune system, and taking part in the treatment of various diseases. Two important factors that can affect the gut microbiome's composition and/or function are the food matrix and methods of food processing. Based on scientific research, the consumption of whole grains can make positive changes in the gut microbiota. Seeds contain different microbiota-accessible substrates that can resist digestion in the upper gastrointestinal tract. Seed germination is one of the simplest and newest food processing approaches to improve seeds' bioavailability and overall nutritional value. During germination, the dormant hydrolytic seed's enzymes have been activated and then metabolize the macromolecules. The quality and quantity of bioactive compounds like prebiotics, fiber, phenolic compounds (PC), total free amino acids, and γ-aminobutyric acid (GABA) can increase even up to 4-10 folds in some cases. These components stimulate the survival and growth of healthful bacteria like probiotics and boost their activity. This effect depends on several parameters, e.g., germination environmental conditions. This review aims to provide up-to-date and latest research about promoting bioactive components during seed germination and investigating their impacts on gut microbiota to understand the possible direct and indirect effects of seed germination on the microbiome and human health.

The Triple Alliance: Microbiome, Mitochondria, and Metabolites in the Context of Age-Related Cognitive Decline and Alzheimer's Disease

Alzheimer's disease (AD) is a progressive, age-related neurodegenerative disorder that affects a large proportion of the older population. It currently lacks effective treatments, placing a heavy burden on patients, families, health care systems, and society. This is mainly due to our limited comprehension of the pathophysiology of AD progression, as well as the lack of effective drug targets and intervention timing to address the underlying pathology. AD is a multifactorial condition, and emerging evidence suggests that abnormalities in the gut microbiota play a significant role as environmental and multifaceted contributors to AD, although the exact mechanisms are yet to be fully explored. Changes in the composition of microbiota influence host neuronal health through their metabolites. These metabolites regulate intestinal epithelia, blood-brain barrier permeability, and neuroinflammation by affecting mitochondrial function. The decline in the proportion of beneficial microbes and their essential metabolites during aging and AD is directly linked to poor mitochondrial function, although the specific mechanisms remain unclear. In this review, we discuss recent developments in understanding the impact of the microbiome and its metabolites on various cell types, their influence on the integrity of the gut and blood-brain barriers, systemic and brain inflammation, and cell-specific effects in AD pathology. This information is expected to pave the way for a new understanding of the interactions between microbiota and mitochondria in AD, providing a foundation for the development of novel treatments for AD.

Poor Oral Health Linked with Higher Risk of Alzheimer's Disease

Alzheimer's disease (AD) is a multifactorial neurodegenerative disease characterized by cognitive and behavioral changes in older adults. Emerging evidence suggests poor oral health is associated with AD, but there is a lack of large-scale clinical studies demonstrating this link. Herein, we used the TriNetX database to generate clinical cohorts and assess the risk of AD and survival among >30 million de-identified subjects with normal oral health (n = 31,418,814) and poor oral health (n = 1,232,751). There was a greater than two-fold increase in AD risk in the poor oral health cohort compared to the normal oral health group (risk ratio (RR): 2.363, (95% confidence interval: 2.326, 2.401)). To reduce potential bias, we performed retrospective propensity score matching for age, gender, and multiple laboratory measures. After matching, the cohorts had no significant differences in survival probability. Furthermore, when comparing multiple oral conditions, diseases related to tooth loss were the most significant risk factor for AD (RR: 3.186, (95% CI: 3.007, 3.376)). Our results suggest that oral health may be important in AD risk, regardless of age, gender, or laboratory measures. However, more large-scale cohort studies are necessary to validate these findings and further evaluate links between oral health and AD.

A mechanism by which gut microbiota elevates permeability and inflammation in obese/diabetic mice and human gut

OBJECTIVE

Ample evidence exists for the role of abnormal gut microbiota composition and increased gut permeability ('leaky gut') in chronic inflammation that commonly co-occurs in the gut in both obesity and diabetes, yet the detailed mechanisms involved in this process have remained elusive.

DESIGN

In this study, we substantiate the causal role of the gut microbiota by use of faecal conditioned media along with faecal microbiota transplantation. Using untargeted and comprehensive approaches, we discovered the mechanism by which the obese microbiota instigates gut permeability, inflammation and abnormalities in glucose metabolism.

RESULTS

We demonstrated that the reduced capacity of the microbiota from both obese mice and humans to metabolise ethanolamine results in ethanolamine accumulation in the gut, accounting for induction of intestinal permeability. Elevated ethanolamine increased the expression of microRNA-miR-101a-3p by enhancing ARID3a binding on the miR promoter. Increased miR-101a-3p decreased the stability of zona occludens-1 (Zo1) mRNA, which in turn, weakened intestinal barriers and induced gut permeability, inflammation and abnormalities in glucose metabolism. Importantly, restoring ethanolamine-metabolising activity in gut microbiota using a novel probiotic therapy reduced elevated gut permeability, inflammation and abnormalities in glucose metabolism by correcting the ARID3a/miR-101a/Zo1 axis.

CONCLUSION

Overall, we discovered that the reduced capacity of obese microbiota to metabolise ethanolamine instigates gut permeability, inflammation and glucose metabolic dysfunctions, and restoring ethanolamine-metabolising capacity by a novel probiotic therapy reverses these abnormalities.

TRIAL REGISTRATION NUMBER

NCT02869659 and NCT03269032.

Unique trans-kingdom microbiome structural and functional signatures predict cognitive decline in older adults

The prevalence of age-related cognitive disorders/dementia is increasing, and effective prevention and treatment interventions are lacking due to an incomplete understanding of aging neuropathophysiology. Emerging evidence suggests that abnormalities in gut microbiome are linked with age-related cognitive decline and getting acceptance as one of the pillars of the Geroscience hypothesis. However, the potential clinical importance of gut microbiome abnormalities in predicting the risk of cognitive decline in older adults is unclear. Till now the majority of clinical studies were done using 16S rRNA sequencing which only accounts for analyzing bacterial abundance, while lacking an understanding of other crucial microbial kingdoms, such as viruses, fungi, archaea, and the functional profiling of the microbiome community. Utilizing data and samples of older adults with mild cognitive impairment (MCI; n = 23) and cognitively healthy controls (n = 25). Our whole-genome metagenomic sequencing revealed that the gut of older adults with MCI harbors a less diverse microbiome with a specific increase in total viruses and a decrease in bacterial abundance compared with controls. The virome, bacteriome, and microbial metabolic signatures were significantly distinct in subjects with MCI versus controls. Selected bacteriome signatures show high predictive potential of cognitive dysfunction than virome signatures while combining virome and metabolic signatures with bacteriome boosts the prediction power. Altogether, the results from our pilot study indicate that trans-kingdom microbiome signatures are significantly distinct in MCI gut compared with controls and may have utility for predicting the risk of developing cognitive decline and dementia- debilitating public health problems in older adults.

The interactive effects of psychosocial stress and diet composition on health in primates

Social disadvantage and diet composition independently impact myriad dimensions of health. They are closely entwined, as social disadvantage often yields poor diet quality, and may interact to fuel differential health outcomes. This paper reviews effects of psychosocial stress and diet composition on health in nonhuman primates and their implications for aging and human health. We examined the effects of social subordination stress and Mediterranean versus Western diet on multiple systems. We report that psychosocial stress and Western diet have independent and additive adverse effects on hypothalamic-pituitary-adrenal and autonomic nervous system reactivity to psychological stressors, brain structure, and ovarian function. Compared to the Mediterranean diet, the Western diet resulted in accelerated aging, nonalcoholic fatty liver disease, insulin resistance, gut microbial changes associated with increased disease risk, neuroinflammation, neuroanatomical perturbations, anxiety, and social isolation. This comprehensive, multisystem investigation lays the foundation for future investigations of the mechanistic underpinnings of psychosocial stress and diet effects on health, and advances the promise of the Mediterranean diet as a therapeutic intervention on psychosocial stress.

Treating Leaky Syndrome in the Over 65s: Progress and Challenges

As we age, our organ functions gradually decline. Circulating factors in the blood and the integrity of organ barriers can become dysfunctional, resulting in a condition known as leaky syndrome. This condition involves the unregulated exchange or leakage of components between organs. However, the triggers of leaky syndrome, as well as its role in aging-related disorders and illnesses, remain largely unknown. In this editorial, we discuss potential mechanisms that originate from the gut and resident microbes (microbiome) to contribute in leaky syndrome. Furthermore, we explore how the food we consume can impact the development of leaky syndrome, potentially influencing the biology of aging and challenges to diagnose the leaky gut condition accurately and clinically.

CDK4-E2F3 signals enhance oxidative skeletal muscle fiber numbers and function to affect myogenesis and metabolism

Understanding how skeletal muscle fiber proportions are regulated is vital to understanding muscle function. Oxidative and glycolytic skeletal muscle fibers differ in their contractile ability, mitochondrial activity, and metabolic properties. Fiber-type proportions vary in normal physiology and disease states, although the underlying mechanisms are unclear. In human skeletal muscle, we observed that markers of oxidative fibers and mitochondria correlated positively with expression levels of PPARGC1A and CDK4 and negatively with expression levels of CDKN2A, a locus significantly associated with type 2 diabetes. Mice expressing a constitutively active Cdk4 that cannot bind its inhibitor p16INK4a, a product of the CDKN2A locus, were protected from obesity and diabetes. Their muscles exhibited increased oxidative fibers, improved mitochondrial properties, and enhanced glucose uptake. In contrast, loss of Cdk4 or skeletal muscle-specific deletion of Cdk4's target, E2F3, depleted oxidative myofibers, deteriorated mitochondrial function, and reduced exercise capacity, while increasing diabetes susceptibility. E2F3 activated the mitochondrial sensor PPARGC1A in a Cdk4-dependent manner. CDK4, E2F3, and PPARGC1A levels correlated positively with exercise and fitness and negatively with adiposity, insulin resistance, and lipid accumulation in human and rodent muscle. All together, these findings provide mechanistic insight into regulation of skeletal muscle fiber-specification that is of relevance to metabolic and muscular diseases.

Sleep deprivation in obesogenic setting alters lipidome and microbiome toward suboptimal inflammation in acute heart failure

Sleep is a fundamental medicine for cardiac homeostasis, and sleep-deprived individuals are prone to higher incidences of heart attack. The lipid-dense diet (obesogenic diet-OBD) is a cumulative risk factor for chronic inflammation in cardiovascular disease; thus, understanding how sleep fragmentation (SF) in an obesity setting impacts immune and cardiac health is an unmet medical need. We hypothesized whether the co-existence of SF with OBD dysregulates gut homeostasis and leukocyte-derived reparative/resolution mediators, thereby impairing cardiac repair. Two-month-old male C57BL/6J mice were randomized first into two groups, then four groups; Control, control + SF, OBD, and OBD + SF mice subjected to myocardial infarction (MI). OBD mice had higher levels of plasma linolenic acid with a decrease in eicosapentaenoic and docosahexaenoic acid. The OBD mice had lower Lactobacillus johnsonii indicating a loss of probiotic microbiota. SF in OBD mice increased Firmicutes/Bacteroidetes ratio indicative of a detrimental change in SF-directed microbiome. OBD + SF group increased in the neutrophil: lymphocyte ratio suggestive of suboptimal inflammation. As a result of SF, resolution mediators (RvD2, RvD3, RvD5, LXA₄ , PD1, and MaR1) decreased and inflammatory mediators (PGD₂ , PGE₂ , PGF_2a , 6k-PGF_1a ) were increased in OBD mice post-MI. At the site of infarction, the proinflammatory cytokines Ccl2, IL1β, and IL-6 were amplified in OBD + SF indicating a robust proinflammatory milieu post-MI. Also, brain circadian genes (Bmal1, Clock) were downregulated in SF-subjected control mice, but remained elevated in OBD mice post-MI. SF superimposed on obesity dysregulated physiological inflammation and disrupted resolving response thereby impaired cardiac repair and signs of pathological inflammation.

Emerging pre-clinical safety assessments for potential probiotic strains: a review

Probiotics are amply studied and applied dietary supplements of greater consumer acceptance. Nevertheless, the emerging evidence on probiotics-mediated potential risks, especially among immunocompromised individuals, necessitates careful and in-depth safety studies. The traditional probiotic safety evaluation methods investigate targeted phenotypic traits, such as virulence factors and antibiotic resistance. However, the rapid innovation in omics technologies has offered an impactful means to ultimately sequence and unknot safety-related genes or their gene products at preliminary levels. Further validating the genome features using an array of phenotypic tests would provide an absolute realization of gene expression dynamics. For safety studies in animal models, the in vivo toxicity evaluation guidelines of chemicals proposed by the Organization for Economic Co-operation and Development (OECD) have been meticulously adopted in probiotic research. Future research should also focus on coupling genome-scale safety analysis and establishing a link to its transcriptome, proteome, or metabolome for a fine selection of safe probiotic strains. Considering the studies published over the years, it can be inferred that the safety of probiotics is strain-host-dose-specific. Taken together, an amalgamation of in silico, in vitro, and in vivo approaches are necessary for a fine scale selection of risk-free probiotic strain for use in human applications.

Intermittent fasting with ketogenic diet: A combination approach for management of chronic diseases

Intermittent Fasting (IF) is the consumption of food and drinks within a defined time, while the ketogenic diet (KD) switches the metabolism from glucose to fats. Continuation of intermittent fasting leads to the generation of ketones, the exact mechanism for a ketogenic diet. This article discusses the types of IF and KD, the monitoring required, and the mechanisms underlying IF and KD, followed by disorders in which the combination strategy could be applied. The strategies for successfully applying combination therapy are included, along with recommendations for the primary care physicians (PCP) which could serve as a handy guide for patient management. This opinion article could serve as the baseline for future clinical studies since there is an utmost need for developing new wholesome strategies for managing chronic disorders.

The effects of prebiotics on gastrointestinal side effects of metformin in youth: A pilot randomized control trial in youth-onset type 2 diabetes

Disclosure summary

Dr. Yadav is Chief Scientific Officer and Co-Founder of Postbiotics Inc and has no conflict of interest with this work. All other authors have no conflicts of interest to disclose.

Background

Metformin is the only approved first-line oral glucose lowering agent for youth with type 2 diabetes mellitus (Y-T2DM) but often causes gastrointestinal (GI) side effects, which may contribute to reduced treatment adherence and efficacy. Prebiotic intake may reduce metformin's side effects by shifting microbiota composition and activity.

Objective

The aims of this study were to determine the feasibility and tolerability of a prebiotic supplement to improve metformin-induced GI symptoms and explore the changes in glycemia and shifts in the microbiota diversity.

Methods

In a two-phase pilot clinical trial, we compared, stool frequency and stool form every 1-2 days, and composite lower GI symptoms (weekly) at initiation of daily metformin combined with either a daily prebiotic or a placebo shake in a 1-week randomized double-blind crossover design (Phase 1), followed by a 1-month open-labeled extension (Phase 2). Plasma glycemic markers and stool samples were collected before and after each phase.

Results

Six Y-T2DM (17.2 ± 1.7y (mean ± SD), 67% male, BMI (42 ± 9 kg/m2), HbA1c (6.4 ± 0.6%)) completed the intervention. Stool frequency, stool composition, and GI symptom scores did not differ by group or study phase. There were no serious or severe adverse events reported, and no differences in metabolic or glycemic markers. After one week Phase 1metformin/placebo Proteobacteria, Enterobacteriaceae, and Enterobacteriales were identified as candidate biomarkers of metformin effects. Principle coordinate analyses of beta diversity suggested that the metformin/prebiotic intervention was associated with distinct shifts in the microbiome signatures at one week and one month.

Conclusion

Administration of a prebiotic fiber supplement during short-term metformin therapy was well tolerated in Y-T2DM and associated with modest shifts in microbial composition. This study provides a proof-of-concept for feasibility exploring prebiotic-metformin-microbiome interactions as a basis for adjunctive metformin therapy.

Clinical trial registration

https://clinicaltrials.gov/, identifier NCT04209075.

SALIVA BASED BIOMARKERS TO IDENTIFY COGNITIVE IMPAIRMENT IN OLDER ADULTS

The prevalence of cognitive decline and dementia is increasing in older adults, their prognosis is poor. Multiple emerging evidence shows that early intervention can delay and /or prevent their progression, however, early-detection markers are invasive, expensive, and not easy to routinely measure. Saliva can be an attractive source of early cognitive decline markers because oral health is linked with cognitive function and oral fluids are connected with brain fluids, and abnormal brain protein markers can leak out to saliva and vice-versa. Using global unbiased LC-MS/MS-based proteomics of 22 saliva samples of cognitively impaired and 39 cognitively healthy older adults (>60 years old) from large, multi-site study called Microbiome in aging Gut and Brain (MiaGB) consortium, revealed that 22 proteins were uniquely for cognitively impaired group while 44 were unique for cognitively healthy controls. In addition, among 78 differentially abundant proteins between cognitively impaired and control groups, half (39) were upregulated, and half (39) were downregulated. Notably, unique proteins in saliva of participants with cognitive impairment were from neurological pathways like NGF signaling, mTOR signaling and LPS-stimulated MAPK signaling. In addition, differentially abundant proteins in participants with cognitive impairment enriched with glucocorticoid receptor signaling, LXR/RXR activation, and L-DOPA degradation-pathways, while they were deficient of pathways like complement C3 and lysozyme pathways. We discovered that the novel saliva proteins and their pathways could blindly differentiate cognitive impaired from healthy older adults. These data suggest that we discovered novel saliva-based proteins that can be used as biomarker to predict/diagnose cognitive-impairment in older adults.

UNIQUE TRANSKINGDOM MICROBIOME SIGNATURES LINKED WITH COGNITIVE DECLINE IN OLDER ADULTS OF MIAGB CONSORTIUM COHORT

The prevalence of age-related cognitive disorders is increasing. Effective prevention and treatment interventions are unavailable due to a poor understanding of aging biology. Multiple emerging evidence indicates that the gut microbiome is linked with age-related disorders; however, their clinical importance in differentiating and predicting the risk of cognitive decline or dementia is largely elusive. Utilizing samples and data of a large, multi-site clinical study across the state of Florida called Microbiome in aging Gut and Brain (MiaGB) Consortium, our whole genome microbiome sequencing revealed that the viral and archaeal population was significantly reduced in the gut of older adults with dementia (n=8) compared to those with mild cognitive impairment (MCI) (n=25) and normal cognition (n=59). Whereas the fungi were exclusively detected in the controls only. Alpha diversity of the participants with MCI and dementia was lower than the cognitively healthy controls. The abundance of Actinobacteria and Verrucomicrobia phyla was higher, and Firmicutes phylum was lower in the participants with dementia. Bacteriophages Lactobacillus prophage Lj771 and Microbacterium phage Min1 were exclusively detected in the gut of the participants with dementia. The study also identifies key metabolic pathways altered in the controls versus the cognitive impairment state. Our biomarker discovery analyses also revealed that these unique microbiome signatures and pathways might have predictive power for cognitive decline and dementia risk and offer new targets for future therapeutic interventions.

Correction: Bioactive peptides derived from milk proteins and their health beneficial potentials: an update

Correction for 'Bioactive peptides derived from milk proteins and their health beneficial potentials: an update' by Ravinder Nagpal et al., Food Funct., 2011, 2, 18-27, DOI: 10.1039/C0FO00016G.

Diet-microbiome-gut-brain nexus in acute and chronic brain injury

In recent years, appreciation for the gut microbiome and its relationship to human health has emerged as a facilitator of maintaining healthy physiology and a contributor to numerous human diseases. The contribution of the microbiome in modulating the gut-brain axis has gained significant attention in recent years, extensively studied in chronic brain injuries such as Epilepsy and Alzheimer’s Disease. Furthermore, there is growing evidence that gut microbiome also contributes to acute brain injuries like stroke(s) and traumatic brain injury. Microbiome-gut-brain communications are bidirectional and involve metabolite production and modulation of immune and neuronal functions. The microbiome plays two distinct roles: it beneficially modulates immune system and neuronal functions; however, abnormalities in the host’s microbiome also exacerbates neuronal damage or delays the recovery from acute injuries. After brain injury, several inflammatory changes, such as the necrosis and apoptosis of neuronal tissue, propagates downward inflammatory signals to disrupt the microbiome homeostasis; however, microbiome dysbiosis impacts the upward signaling to the brain and interferes with recovery in neuronal functions and brain health. Diet is a superlative modulator of microbiome and is known to impact the gut-brain axis, including its influence on acute and neuronal injuries. In this review, we discussed the differential microbiome changes in both acute and chronic brain injuries, as well as the therapeutic importance of modulation by diets and probiotics. We emphasize the mechanistic studies based on animal models and their translational or clinical relationship by reviewing human studies.

Intestinal FFA3 mediates obesogenic effects in mice on a Western diet

Free fatty acid receptor 3 (FFA3) is a recently-deorphanized G-protein-coupled receptor. Its ligands are short-chain fatty acids (SCFAs), which are key nutrients derived from the gut microbiome fermentation process that play diverse roles in the regulation of metabolic homeostasis and glycemic control. FFA3 is highly expressed within the intestine, where its role and its effects on physiology and metabolism are unclear. Previous in vivo studies involving this receptor have relied on global knockout mouse models, making it difficult to isolate intestine-specific roles of FFA3. To overcome this challenge, we generated an intestine-specific knockout mouse model for FFA3, Villin-Cre-FFA3 (Vil-FFA3). Model validation and general metabolic assessment of male mice fed a standard chow diet revealed no major congenital defects. Because dietary changes are known to alter gut microbial composition, and thereby SCFA production, an obesogenic challenge was performed on male Vil-FFA3 mice and their littermate controls to probe for a phenotype on a high-fat, high-sugar "Western diet" (WD) compared with a low-fat control diet (CD). Vil-FFA3 mice versus FFA3fl/fl controls on WD, but not CD, were protected from the development of diet-induced obesity and exhibited significantly less fat mass as well as smaller adipose depositions and adipocytes. Although overall glycemic control was unchanged in the WD-fed Vil-FFA3 group, fasted glucose levels trended lower. Intestinal inflammation was significantly reduced in the WD-fed Vil-FFA3 mice, supporting protection from obesogenic effects. Furthermore, we observed lower levels of gastric inhibitory protein (GIP) in the WD-fed Vil-FFA3 mice, which may contribute to phenotypic changes. Our findings suggest a novel role of intestinal FFA3 in promoting the metabolic consequences of a WD, including the development of obesity and inflammation. Moreover, these data support an intestine-specific role of FFA3 in whole body metabolic homeostasis and in the development of adiposity.NEW & NOTEWORTHY Here, we generated a novel intestine-specific knockout mouse model for FFA3 (Vil-FFA3) and performed a comprehensive metabolic characterization of mice in response to an obesogenic challenge. We found that Vil-FFA3 mice fed with a Western diet were largely protected from obesity, exhibiting significantly lower levels of fat mass, lower intestinal inflammation, and altered expression of intestinal incretin hormones. Results support an important role of intestinal FFA3 in contributing to metabolism and in the development of diet-induced obesity.

Abstract P3067: Sleep Deprivation In Obesogenic Setting Alters Lipidome And Microbiome Toward Suboptimal Inflammation In Acute Heart Failure

Introduction: Sleep is fundamental medicine for cardiac homeostasis and the immune fitness of human health. Sleep-deprived individuals are prone to higher incidences of a heart attack. The lipid-dense diet (obesogenic diet-OBD) is a cumulative risk factor for chronic inflammation in cardiovascular disease, thus understanding how sleep fragmentation (SF) in obesity setting impacts immune and cardiac health is an unmet medical need to develop novel therapeutics. Hypothesis: We hypothesized whether the co-existence of SF with OBD dysregulates gut homeostasis and leukocyte-derived reparative mediators thereby impairing cardiac repair.

Methods: Two months old male C57BL/6J mice were randomized into two main groups; control (fed standard lab chow) and OBD (fed 10% w/w safflower oil-enriched diet) for 2 months. For SF, mice were subjected to SF chamber (2-minute interval bar sweep in light period (0700–1900 h) for 3 days. Mice of control, control+SF, OBD control, OBD+SF groups were further subjected to permanent coronary artery ligation to induce acute heart failure.

Results: OBD fed mice had higher levels of plasma linolenic acid with a decrease in eicosapentaenoic acid and docosahexaenoic acid. The OBD mice had lower levels of Lactobacillus johnsonii indicating loss of probiotic microbiota. SF in OBD mice increased Firmicutes/Bacteroidetes (F/B) ratio indicative of a detrimental change in SF-directed microbiome signatures. OBD+SF group increased in the neutrophil: lymphocyte ratio suggestive of suboptimal inflammation. As a result of SF, resolution mediators (RvD2, RvD3, RvD5, LXA 4 , PD1, and MaR1) decreased and inflammatory mediators (PGD 2 , PGE 2 , PGF 2a , 6k-PGF 1a ) were increased post- MI in OBD fed mice. At the site of infarction, the proinflammatory cytokines; Ccl2, IL1β , and IL-6 were amplified in OBD+SF indicating a robust proinflammatory milieu. OBD+SF group showed signs of neutropenia in the spleen with pre-activation of CD169 macrophages. Also, brain circadian genes ( Bmal1, Clock) were downregulated in SF subjected control mice but remained elevated in OBD mice post-MI.

Conclusion: SF superimposed on obesity dysregulated physiological inflammation and disrupted resolving response thereby impaired cardiac repair and signs of pathological inflammation.

Increasing the use of perioperative risk scoring in emergency laparotomy: nationwide quality improvement programme

Background

Emergency laparotomy is associated with high morbidity and mortality. The early identification of high-risk patients allows for timely perioperative care and appropriate resource allocation. The aim of this study was to develop a nationwide surgical trainee-led quality improvement (QI) programme to increase the use of perioperative risk scoring in emergency laparotomy.

Methods

The programme was structured using the active implementation framework in 15 state-funded Irish hospitals to guide the staged implementation of perioperative risk scoring. The primary outcome was a recorded preoperative risk score for patients undergoing an emergency laparotomy at each site.

Results

The rate of patients undergoing emergency laparotomy receiving a perioperative risk score increased from 0–11 per cent during the exploratory phase to 35–100 per cent during the full implementation phase. Crucial factors for implementing changes included an experienced central team providing implementation support, collaborator engagement, and effective communication and social relationships.

Conclusions

A trainee-led QI programme increased the use of perioperative risk assessment in patients undergoing emergency laparotomy, with the potential to improve patient outcomes and care delivery.

Gut microbiome/metabolome predicts response to immune checkpoint blockers (ICB) in patients with recurrent metastatic head and neck squamous cell cancer (RM HNSCC)

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Background: Gut microbiome has emerged as an important predictor of response to ICB therapy in various cancers, most notably in melanoma. Due to functional redundancy of microbiota, there has been lack of consistency in gut microbial signature associated with ICB response. Microbial metabolites in addition to taxonomy may play a superior role in predicting response to ICB. Gut microbiome/metabolome signatures of ICB response is unknown in RM HNSCC patients. Methods: Two cohorts of patients were included (stool and plasma samples were collected)- cohort 1, newly diagnosed RM HNSCC patients starting first line ICB, for whom samples were collected before ICB initiation (baseline) and post-treatment at 3, 6, and 12 months. Cohort 2 with durable response (disease control lasting ≥ 6 months), with single sample collected at study entry. 16s rRNA sequencing was performed on stool samples while plasma metabolites were quantitated using Q Exactive plus Orbitrap mass spectrometer. Response was defined as partial response (PR) or complete response (CR) as per RECIST 1.1 Results: The 16-S sequence was carried on 31 samples (cohort 1- 16 baseline, 7 post treatment; cohort 2- 8 durable responders). Targeted metabolomics was completed on 92 plasma samples [cohort 1-27 baseline and 50 post-treatment, cohort 2- 15]. Responders had a significantly higher Shannon’s diversity index, lower Fermicutes to Bacteroidetes ratio, and were enriched with genus Bacteroides and Lachnospiracea incerate sedis at baseline and post treatment, compared to non-responders (p < 0.05). At species level, baseline and post treatment microbiome of responders was enriched with Eubacterium oxidoreducens and Bacteroides uniformis. Ruminococcus was preferentially enriched in durable responders. Targeted analysis of plasma metabolites (associated with gut microbial metabolism) showed that responders had a significantly lower baseline adenosine, Inosine and xanthine level as compared to non responders. Further, Inosine levels decreased with response, while levels increased in non-responders (p < 0.05), suggestive of consumption by re-activated T cells Further, ICB responders had significantly lower Kynurenine to tryptophan ratio compared to non responders Conclusions: This is the first study evaluating association of gut microbiome and metabolome on response to first line ICB, in RM HNSCC patients. We found higher diversity and specific gut microbial signatures associated with ICB response. Interestingly, we found that inosine and kynurenine/tryptophan pathways, both which play a crucial role in host as well as gut microbial metabolism were differentially expressed in ICB responders. Our results if validated in larger cohort, lays groundwork for gut microbiome and importantly microbial metabolite modulation to improve response to ICB in RM HNSCC.

Diabetes and seeds: New horizon to promote human nutrition and anti-diabetics compounds in grains by germination

Type 2 diabetes (T2D) is a complex and heterogeneous chronic metabolic disorder disease that is associated with high blood sugar. Because of the side effects of synthetic drugs on T2D patients and their economic burden, interest in plant-derived functional foods like grains with biological activities has developed. Based on scientific reports, whole grains are rich sources of energy, nutrients, and bioactive compounds and are assumed to have beneficial health effects on glucose enzymes regulation or hyperglycemia. Nowadays, different methods have been applied to enhance whole seed healthful properties and anti-diabetic compounds, and germination is one of them. Germination (sprouting) is a cost-effective method for boosting the activity of endogenous seed enzymes and modifying the structure of macromolecules. Some of these macromolecules like bioactive peptides, polyphenols, dietary fiber, and vitamins are related to diabetes management. Determining the best germination condition can help to promote these anti-diabetics properties of compounds. This study presents relevant information about diabetes, the effect of seed germination on releasing bioactive compounds, and optimizing environmental germination conditions to improve the anti-diabetic compounds in seeds for reaching functional food.

Microbiome in aging of Gut and Brain (MiaGB): paving the ways to understand gut-brain axis in aging

Decades of aging research established several well-characterized theories of aging, yet as the studies often focus on different cellular mechanisms there is overall agreement that organismal aging is characterized by multi-factorial degenerative processes resulting from multiple alterations of different molecular pathways compromising cellular or tissues functions. Due to this complexity aging is a major risk factor for multiple diseases including cardiovascular diseases, cancers, diabetes, and neurological diseases such as Alzheimer’s disease. It is well known that this multi-factorial process in some cases might be accelerated by the dysfunction of one organ as a source of chronic low-grade inflammation. Importantly, most recent studies provide strong evidence that the gut microbiome represents a new independent organ system mainly composed of a variety of microorganisms recognized as the microbiome. The high integrity of the microbiome with the host physiology and biochemical interactions between specific bacteria and cellular processes supports its organ-like function in organismal health and the process of aging. However, it is important to better understand what causes potential cellular stress to accelerate a variety of pathological changes, what is the specific role of our gut microbiome in process of human aging, and how we could use this knowledge to prevent or delay aging pathology.

The Impact of a Mediterranean Diet on the Gut Microbiome in Healthy Human Subjects: A Pilot Study

BACKGROUND AND AIMS

Despite the reported salutary benefits of a Mediterranean diet (MD) on a wide variety of health conditions, the specific microbial changes associated with an MD within the gastrointestinal (GI) tract are not well studied. Specifically, although population and survey-based studies have shown microbial changes, there are no published data on how an MD alters the gut flora in a controlled setting.

METHODS

We recruited 10 healthy subjects, each of whom gave a stool sample at baseline and then was provided with prepared meals of a "typical" American diet; after 2 weeks, a second stool sample was collected. All subjects were then provided with prepared meals based on the MD for another 2 weeks, followed by a final stool sample collection. Stool samples were batch analyzed with DNA extraction, and sequencing libraries were generated. Measures of bacterial diversity, species richness, and enterotypes were performed.

RESULTS

All ten subjects tolerated the diets well. Bacterial diversity increased with an MD, as measured by alpha diversity via the Simpson index. Furthermore, there were significant differences in 5 bacterial genera between the 2 diets.

CONCLUSION

This small pilot study of controlled diets demonstrates that the MD can rapidly alter the gut microbiome in healthy subjects at the level of global microbial diversity and individual genera. These data confirm the findings of previous observational studies and establish the feasibility of conducting longer term studies on the impact of the MD on the flora of the GI tract and its relationship to digestive diseases.

Gut-Brain Axis as a Pathological and Therapeutic Target for Neurodegenerative Disorders

Human lifestyle and dietary behaviors contribute to disease onset and progression. Neurodegenerative diseases (NDDs), considered multifactorial disorders, have been associated with changes in the gut microbiome. NDDs display pathologies that alter brain functions with a tendency to worsen over time. NDDs are a worldwide health problem; in the US alone, 12 million Americans will suffer from NDDs by 2030. While etiology may vary, the gut microbiome serves as a key element underlying NDD development and prognosis. In particular, an inflammation-associated microbiome plagues NDDs. Conversely, sequestration of this inflammatory microbiome by a correction in the dysbiotic state of the gut may render therapeutic effects on NDDs. To this end, treatment with short-chain fatty acid-producing bacteria, the main metabolites responsible for maintaining gut homeostasis, ameliorates the inflammatory microbiome. This intimate pathological link between the gut and NDDs suggests that the gut-brain axis (GBA) acts as an underexplored area for developing therapies for NDDs. Traditionally, the classification of NDDs depends on their clinical presentation, mostly manifesting as extrapyramidal and pyramidal movement disorders, with neuropathological evaluation at autopsy as the gold standard for diagnosis. In this review, we highlight the evolving notion that GBA stands as an equally sensitive pathological marker of NDDs, particularly in Alzheimer’s disease, Parkinson’s disease, amyotrophic lateral sclerosis and chronic stroke. Additionally, GBA represents a potent therapeutic target for treating NDDs.

Corrigendum to "Cholesterol-Lowering Probiotics as Potential Biotherapeutics for Metabolic Diseases"

[This corrects the article DOI: 10.1155/2012/902917.].

A novel probiotics therapy for aging-related leaky gut and inflammation

Inflammaging characterized with increased low grade inflammation in older adults is common determinant of unhealthy aging; and is a major risk factor of morbidity and mortality in older adults. The precise origin of inflammation in older adults is not known, however, emerging evidence indicate that increased intestinal epithelial permeability (leaky gut) and abnormal (dysbiotic) gut microbiota could be one of the key source. However, no preventive and treatment therapies are available to reverse the leaky gut and microbiome dysbiosis in older adults. Here, we presented the evidence that a human-origin probiotics cocktail containing 5 Lactobacillus and 5 Enterococcus strains isolated from healthy human infant gut can ameliorate aging-related metabolic, physical and cognitive dysfunctions in older mice. We show that the Feeding this probiotic cocktail prevented high-fat diet–induced (HFD-induced) abnormalities in glycose metabolism and physical functions in older mice and reduced microbiota dysbiosis, leaky gut, inflammation. Probiotic-modulated gut microbiota reduced leaky gut by increasing tight junctions on intestinal epithelia, which in turn reduced inflammation. Mechanistically, probiotics increased bile salt hydrolase activity in older microbiota, which in turn increased taurine deconjugation from bile acids to increase free taurine abundance in the gut. We further show that taurine stimulated tight junctions and suppressed gut leakiness. Further, taurine increased life span, reduced adiposity and leaky gut, and enhanced physical function in Caenorhabditis elegans. Whether this novel human origin probiotic therapy could prevent or treat aging-related leaky gut and inflammation in the elderly by reversing microbiome dysbiosis requires evaluation.

Activation of Microbiota Sensing - Free Fatty Acid Receptor 2 Signaling Ameliorates Amyloid-β Induced Neurotoxicity by Modulating Proteolysis-Senescence Axis

Multiple emerging evidence indicates that the gut microbiota contributes to the pathology of Alzheimer's disease (AD)-a debilitating public health problem in older adults. However, strategies to beneficially modulate gut microbiota and its sensing signaling pathways remain largely unknown. Here, we screened, validated, and established the agonists of free fatty acid receptor 2 (FFAR2) signaling, which senses beneficial signals from short chain fatty acids (SCFAs) produced by microbiota. The abundance of SCFAs, is often low in the gut of older adults with AD. We demonstrated that inhibition of FFAR2 signaling increases amyloid-beta (Aβ) stimulated neuronal toxicity. Thus, we screened FFAR2 agonists using an in-silico library of more than 144,000 natural compounds and selected 15 of them based on binding with FFAR2-agonist active sites. Fenchol (a natural compound commonly present in basil) was recognized as a potential FFAR2 stimulator in neuronal cells and demonstrated protective effects against Aβ-stimulated neurodegeneration in an FFAR2-dependent manner. In addition, Fenchol reduced AD-like phenotypes, such as Aβ-accumulation, and impaired chemotaxis behavior in Caenorhabditis (C.) elegans and mice models, by increasing Aβ-clearance via the promotion of proteolysis and reduced senescence in neuronal cells. These results suggest that the inhibition of FFAR2 signaling promotes Aβ-induced neurodegeneration, while the activation of FFAR2 by Fenchol ameliorates these abnormalities by promoting proteolytic Aβ-clearance and reducing cellular senescence. Thus, stimulation of FFAR2 signaling by Fenchol as a natural compound can be a therapeutic approach to ameliorate AD pathology.

Diet Alters Entero-Mammary Signaling to Regulate the Breast Microbiome and Tumorigenesis

Obesity and poor diet often go hand-in-hand, altering metabolic signaling and thereby impacting breast cancer risk and outcomes. We have recently demonstrated that dietary patterns modulate mammary microbiota populations. An important and largely open question is whether the microbiome of the gut and mammary gland mediates the dietary effects on breast cancer. To address this, we performed fecal transplants between mice on control or high-fat diets (HFD) and recorded mammary tumor outcomes in a chemical carcinogenesis model. HFD induced protumorigenic effects, which could be mimicked in animals fed a control diet by transplanting HFD-derived microbiota. Fecal transplants altered both the gut and mammary tumor microbiota populations, suggesting a link between the gut and breast microbiomes. HFD increased serum levels of bacterial lipopolysaccharide (LPS), and control diet-derived fecal transplant reduced LPS bioavailability in HFD-fed animals. In vitro models of the normal breast epithelium showed that LPS disrupts tight junctions (TJ) and compromises epithelial permeability. In mice, HFD or fecal transplant from animals on HFD reduced expression of TJ-associated genes in the gut and mammary gland. Furthermore, infecting breast cancer cells with an HFD-derived microbiome increased proliferation, implicating tumor-associated bacteria in cancer signaling. In a double-blind placebo-controlled clinical trial of patients with breast cancer administered fish oil supplements before primary tumor resection, dietary intervention modulated the microbiota in tumors and normal breast tissue. This study demonstrates a link between the gut and breast that mediates the effect of diet on cancer. SIGNIFICANCE: This study demonstrates that diet shifts the microbiome in the gut and the breast tumor microenvironment to affect tumorigenesis, and oral dietary interventions can modulate the tumor microbiota in patients with breast cancer. GRAPHICAL ABSTRACT: http://cancerres.aacrjournals.org/content/canres/81/14/3890/F1.large.jpg.

Diet, obesity, and the gut microbiome as determinants modulating metabolic outcomes in a non-human primate model

BACKGROUND

The objective of this study was to increase understanding of the complex interactions between diet, obesity, and the gut microbiome of adult female non-human primates (NHPs). Subjects consumed either a Western (n=15) or Mediterranean (n=14) diet designed to represent human dietary patterns for 31 months. Body composition was determined using CT, fecal samples were collected, and shotgun metagenomic sequencing was performed. Gut microbiome results were grouped by diet and adiposity.

RESULTS

Diet was the main contributor to gut microbiome bacterial diversity. Adiposity within each diet was associated with subtle shifts in the proportional abundance of several taxa. Mediterranean diet-fed NHPs with lower body fat had a greater proportion of Lactobacillus animalis than their higher body fat counterparts. Higher body fat Western diet-fed NHPs had more Ruminococcus champaneliensis and less Bacteroides uniformis than their low body fat counterparts. Western diet-fed NHPs had significantly higher levels of Prevotella copri than Mediterranean diet NHPs. Western diet-fed subjects were stratified by P. copri abundance (P. copri^HIGH versus P. copri^LOW), which was not associated with adiposity. Overall, Western diet-fed animals in the P. copri^HIGH group showed greater proportional abundance of B. ovatus, B. faecis, P. stercorea, P. brevis, and Faecalibacterium prausnitzii than those in the Western P. copri^LOW group. Western diet P. copri^LOW subjects had a greater proportion of Eubacterium siraeum. E. siraeum negatively correlated with P. copri proportional abundance regardless of dietary consumption. In the Western diet group, Shannon diversity was significantly higher in P. copri^LOW when compared to P. copri^HIGH subjects. Furthermore, gut E. siraeum abundance positively correlated with HDL plasma cholesterol indicating that those in the P. copri^LOW population may represent a more metabolically healthy population. Untargeted metabolomics on urine and plasma from Western diet-fed P. copri^HIGH and P. copri^LOW subjects suggest early kidney dysfunction in Western diet-fed P. copri^HIGH subjects.

CONCLUSIONS

In summary, the data indicate diet to be the major influencer of gut bacterial diversity. However, diet and adiposity must be considered together when analyzing changes in abundance of specific bacterial taxa. Interestingly, P. copri appears to mediate metabolic dysfunction in Western diet-fed NHPs. Video abstract.

Diet-Microbiota-Brain Axis in Alzheimer's Disease

BACKGROUND

Alzheimer's disease (AD) is the most common form of dementia, particularly in older adults, with clinical manifestations of progressive cognitive decline and functional impairment. The prevalence of AD and related dementia is mounting worldwide, but its etiology remains unresolved, with no available preventative or ameliorative therapy. Emerging evidence suggests that the gut microbiota of patients with AD is different from cognitively normal counterparts.

SUMMARY

Communication between gut and brain (gut-brain axis) plays a crucial role in AD pathology. Bacteria inhabiting the gut strongly influence this gut-brain axis and thus may participate in AD pathology. Diet, one of the strongest modulators of gut microbiota, also strongly influences brain health and AD pathology. Gut microbiota metabolites including short-chain fatty acids, pro-inflammatory factors, and neurotransmitters may also affect AD pathogenesis and associated cognitive decline. Therefore, investigation of diet-microbiota-brain axis is important to better understand its contribution in AD pathology and its potential use as a target to prevent and treat AD. Herein, we discuss the link between AD and gut microbiota and ponder how microbiota modulation through nutritional approaches may offer avenues for discovering novel preventive and therapeutic strategies against AD. Key Message: A strong association exists between lifestyle factors and AD prevalence wherein unhealthy dietary factors have been linked to neurodegeneration. Specific prudent dietary patterns might help in preventing or delaying AD progression by affecting β-amyloid production and tau processing and regulating AD-associated inflammation, metabolism and oxidative stress, plausibly via modulating gut microbiota.

New Horizons in Microbiota and Metabolic Health Research

Decade-old studies have demonstrated that microbes living in our gut (microbiota) contribute to both maintaining normal metabolic function and to the pathology of metabolic diseases, such as obesity and diabetes. Emerging evidence suggests that gut microbiota influences the personalized effects of diets and drugs and impact the gut-brain axis and leaky gut inflammation to control metabolic function/diseases. Gut microbiota can be an ideal source of prognostic markers and therapies for metabolic diseases. Here we discuss the emerging concepts in the area of microbiota and metabolic interactions in personalized nutrition, drug response, and disease prognosis.

Development of a Novel Oral Delivery Vehicle for Probiotics

BACKGROUND

There is a significant interest in effective oral drug delivery of therapeutic substances. For probiotics, there is a particular need for a delivery platform that protects the bacteria from destruction by the acidic stomach while enabling targeted delivery to the intestine where microbiota naturally reside. The use of probiotics and how they impact the gut microbiota is a growing field and holds promise for the treatment of a variety of gastrointestinal diseases, including irritable bowel disease Crohn's disease and C. diff and other diseases, such as obesity, diabetes, Parkinson's, and Alzheimer's diseases.

OBJECTIVE

The aim of this research was to use our newly developed chemically-modified alginate hydrogel with the characteristic feature of stability in acidic environments but disintegration under neutral-basic pH conditions to design a novel system for effective targeted delivery of ingested probiotics.

METHODS AND RESULTS

We have used the approach of encapsulation of bacterial cells in the hydrogel of the modified alginate with in vitro studies in both simulated stomach acid and intestinal fluid conditions to demonstrate the potential application of this novel platform in oral delivery of probiotics. Our data provide a proof-of-concept that enables further studies in vivo with this delivery platform.

CONCLUSION

We have demonstrated in the present study that our chemically modified alginate hydrogel is resistant to acidic conditions and protects bacterial cells encapsulated in it, but it is sensitive to neutral-basic pH conditions under which it disintegrates and releases its viable bacteria cell payload. Our data provide a proof-ofconcept that enables further studies in vivo with this delivery platform for the efficacy of therapeutic bacteria in various disease conditions.

Senolytic combination of Dasatinib and Quercetin alleviates intestinal senescence and inflammation and modulates the gut microbiome in aged mice

Cellular senescence contributes to age-related disorders including physical dysfunction, disabilities and mortality caused by tissue inflammation and damage. Senescent cells accumulate in multiple tissues with aging and at etiological sites of multiple chronic disorders. The senolytic drug combination, Dasatinib plus Quercetin (D+Q), is known to reduce senescent cell abundance in aged mice. However, the effects of long-term D+Q treatment on intestinal senescent cell and inflammatory burden and microbiome composition in aged mice remain unknown. Here, we examine the effect of D+Q on senescence (p16 Ink4a and p21 Cip1) and inflammation (Cxcl1, Il1β, Il6, Mcp1, and Tnfα) markers in small (ileum) and large (caecum and colon) intestine in aged mice (n=10) compared to age-matched placebo-treated mice (n=10). Additionally, we examine microbial composition along the intestinal tract in these mice. D+Q-treated mice show significantly lower senescent cell (p16 and p21 expression) and inflammatory (Cxcl1, Il1β, Il6, Mcp1 and Tnfα expression) burden in small and large intestine compared with control mice. Further, we find specific microbial signatures in ileal, cecal, colonic and fecal regions that are distinctly modulated by D+Q, with modulation being most prominent in small intestine. Further analyses reveal specific correlation of senescence and inflammation markers with specific microbial signatures. Together, these data demonstrate that the senolytic treatment reduces intestinal senescence and inflammation while altering specific microbiota signatures and suggest that the optimized senolytic regimens might improve health via reducing intestinal senescence, inflammation and microbial dysbiosis in older subjects.

Metformin Improves Cognition by Reducing Leaky Gut and Benefiting Gut Microbiome–Goblet Cell–Mucin Axis

Older adults are suffering from several aging-related illnesses including cognitive decline and effective strategies to prevent and/or treat them are lacking, because of a poor understanding of therapeutic targets. Low-grade inflammation is a key risk factor of aging-related morbidities and mortalities, and it is often higher in older adults. Although, precise reasons for increased inflammation remain unknown, however, emerging evidence indicates that abnormal (dysbiotic) gut microbiome and dysfunctional gut permeability (leaky gut) are linked with increased inflammation in older adults. However, no drugs are available to treat aging-related microbiome dysbiosis and leaky gut, and little is known about the cellular and molecular processes that can be targeted to reduce leaky gut in older adults. Here, we demonstrated that metformin, a safe FDA approved antidiabetic drug, decreased leaky gut and inflammation in older obese mice, by beneficially modulating the gut microbiota. In addition, metformin increased goblet cell mass and mucin production in the older gut, thereby decreasing leaky gut and inflammation. Mechanistically, metformin increased the goblet cell differentiation markers by suppressing Wnt signaling. Our results suggest that metformin can prevent and treat aging-related leaky gut and inflammation, by beneficially modulating gut microbiome/goblet cell/mucin biology.

Health-promoting role of dietary bioactive compounds through epigenetic modulations: a novel prophylactic and therapeutic approach

The epigenome is an overall epigenetic state of an organism, which is as important as that of the genome for normal development and functioning of an individual. Epigenetics involves heritable but reversible changes in gene expression through alterations in DNA methylation, histone modifications and regulation of non-coding RNAs in cells, without any change in the DNA sequence. Epigenetic changes are owned by various environmental factors including pollution, microbiota and diet, which have profound effects on epigenetic modifiers. The bioactive compounds present in the diet mainly include curcumin, resveratrol, catechins, quercetin, genistein, sulforaphane, epigallocatechin-3-gallate, alkaloids, vitamins, and peptides. Bioactive compounds released during fermentation by the action of microbes also have a significant effect on the host epigenome. Besides, recent studies have explored the new insights in vitamin's functions through epigenetic regulation. These bioactive compounds exert synergistic, preventive and therapeutic effects when combined as well as when used with chemotherapeutic agents. Therefore, these compounds have potential of therapeutic agents that could be used as "Epidrug" to treat many inflammatory diseases and various cancers where chemotherapy results have many side effects. In this review, the effect of diet derived bioactive compounds through epigenetic modulations on in vitro and in vivo models is discussed.

Role of TRP Channels in Shaping the Gut Microbiome

Transient receptor potential (TRP) channel family proteins are sensors for pain, which sense a variety of thermal and noxious chemicals. Sensory neurons innervating the gut abundantly express TRPA1 and TRPV1 channels and are in close proximity of gut microbes. Emerging evidence indicates a bi-directional gut–brain cross-talk in several entero-neuronal pathologies; however, the direct evidence of TRP channels interacting with gut microbial populations is lacking. Herein, we examine whether and how the knockout (KO) of TRPA1 and TRPV1 channels individually or combined TRPA1/V1 double-knockout (dKO) impacts the gut microbiome in mice. We detect distinct microbiome clusters among the three KO mouse models versus wild-type (WT) mice. All three TRP-KO models have reduced microbial diversity, harbor higher abundance of Bacteroidetes, and a reduced proportion of Firmicutes. Specifically distinct arrays in the KO models are determined mainly by S24-7, Bacteroidaceae, Clostridiales, Prevotellaceae, Helicobacteriaceae, Rikenellaceae, and Ruminococcaceae. A1KO mice have lower Prevotella, Desulfovibrio, Bacteroides, Helicobacter and higher Rikenellaceae and Tenericutes; V1KO mice demonstrate higher Ruminococcaceae, Lachnospiraceae, Ruminococcus, Desulfovibrio and Mucispirillum; and A1V1dKO mice exhibit higher Bacteroidetes, Bacteroides and S24-7 and lower Firmicutes, Ruminococcaceae, Oscillospira, Lactobacillus and Sutterella abundance. Furthermore, the abundance of taxa involved in biosynthesis of lipids and primary and secondary bile acids is higher while that of fatty acid biosynthesis-associated taxa is lower in all KO groups. To our knowledge, this is the first study demonstrating distinct gut microbiome signatures in TRPA1, V1 and dKO models and should facilitate prospective studies exploring novel diagnostic/ therapeutic modalities regarding the pathophysiology of TRP channel proteins.