Intestinal colonization regulates systemic anti-commensal immune sensitivity and hyperreactivity.

Healthy host-microbial mutualism with our intestinal microbiota relies to a large degree on compartmentalization and careful regulation of adaptive mucosal and systemic anti-microbial immune responses. However, commensal intestinal bacteria are never exclusively or permanently restricted to the intestinal lumen and regularly reach the systemic circulation. This results in various degrees of commensal bacteremia that needs to be appropriately dealt with by the systemic immune system. While most intestinal commensal bacteria, except for pathobionts or opportunistic pathogen, have evolved to be non-pathogenic, this does not mean that they are non-immunogenic. Mucosal immune adaptation is carefully controlled and regulated to avoid an inflammatory response, but the systemic immune system usually responds differently and more vigorously to systemic bacteremia. Here we show that germ-free mice have increased systemic immune sensitivity and display anti-commensal hyperreactivity in response to the addition of a single defined T helper cell epitope to the outer membrane porin C (OmpC) of a commensal Escherichia coli strain demonstrated by increased E. coli-specific T cell-dependent IgG responses following systemic priming. This increased systemic immune sensitivity was not observed in mice colonized with a defined microbiota at birth indicating that intestinal commensal colonization also regulates systemic, and not only mucosal, anti-commensal responses. The observed increased immunogenicity of the E. coli strain with the modified OmpC protein was not due to a loss of function and associated metabolic changes as a control E. coli strain without OmpC did not display increased immunogenicity.

Goji berry leaf exerts a comparable effect against colitis and microbiota dysbiosis to its fruit in dextran-sulfate-sodium-treated mice.

Goji berry and mulberry are both popular berries with anti-colitis effects, but their leaves have received less attention. In this study, the anti-colitis effects of goji berry leaf and mulberry leaf were investigated in dextran-sulfate-sodium-induced colitis C57BL/6N mice compared with their fruits. Goji berry leaf and goji berry reduced colitic symptoms and ameliorated tissue damage, while mulberry leaf did not. ELISA and western blotting analysis suggested that goji berry showed the best performance in inhibiting the overproduction of pro-inflammatory cytokines (TNF-α, IL-6 and IL-10) and improving damaged colonic barrier (occludin and claudin-1). Besides, goji berry leaf and goji berry reversed the gut microbiota dysbiosis by increasing the abundance of beneficial bacteria like Bifidobacterium and Muribaculaceae, and decreasing the abundance of harmful bacteria like Bilophila and Lachnoclostridium. Goji berry, mulberry and goji berry leaf could restore acetate, propionate, butyrate and valerate to ameliorate inflammation, while mulberry leaf could not restore butyrate. To the best of our knowledge, this is the first report on the comparison of the anti-colitis effects of goji berry leaf, mulberry leaf and their fruits, which is meaningful for the rational utilization of goji berry leaf as a functional food.

Structure and In Vitro Fermentation Characteristics of Polysaccharides Sequentially Extracted from Goji Berry (Lycium barbarum) Leaves.

Herein, the chelating agent-soluble fraction (CA), sodium carbonate-soluble fraction (SC), and sodium hydroxide-soluble fraction (SH) were sequentially extracted from the cell wall of goji berry (Lycium barbarum) leaves. Furthermore, SC was purified with Q-Sepharose fast flow resin to obtain the neutral sugar fraction (SC-I) and acid sugar fraction (SC-II). Physicochemical properties of polysaccharides were characterized by high-performance anion-exchange chromatography with pulsed amperometry detection, size exclusion chromatography-multi-angle laser light scattering, Fourier transform infrared spectroscopy, nuclear magnetic resonance, and atomic force microscopy analysis. Additionally, the impact of polysaccharides on modulating human gut microbiota was investigated by in vitro fermentation. A high amount of galacturonic acid (GalA) in CA showed that it was an aggregation of linear homogalacturonan. SC was the main pectic polysaccharide fraction and rich in neutral sugars. SC-I was the neutral sugar fraction with an extremely high molecular weight (2.055 × 106 Da), while SC-II was the acid sugar fraction with a low molecular weight (1.766 × 105 Da). SH seemed like a mixture of pectin and hemicellulose. All the five polysaccharides significantly (P < 0.05) increased the abundance of Bacteroides, Bifidobacteria, and Lactobacilli. To the best of our knowledge, this is the first report on the structure and fermentation characteristics of goji berry leaf polysaccharides, which is meaningful to provide a structural basis for further bioactivity research.

Enzyme-extracted raspberry pectin exhibits a high-branched structure and enhanced anti-inflammatory properties than hot acid-extracted pectin.

To characterize the structure of purified raspberry pectin and discuss the impact of different extraction methods on the pectin structure, raspberry pectin was extracted by hot-acid and enzyme method and purified by stepwise ethanol precipitation and ion-exchange chromatography isolation. Enzyme-extracted raspberry pectin (RPE50%-3) presented relatively intact structure with molecular weight of 5 × 104 g/mol and the degree of methylation was 39%. The 1D/2D NMR analysis demonstrated RPE50%-3 was a high-branched pectin mainly containing 50% homogalacturonan, 16% branched α-1,5-arabinan and α-1,3-arabinan, 18% ß-1,4-galactan and ß-1,6-galactan. Acid-extracted raspberry pectin (RPA50%-3) contained less arabinan than RPE50%-3. Moreover, RPE50%-3 inhibited the nitric oxide (NO), TNF-α, IL-6 production of lipopolysaccharide-induced macrophages by 67%, 22% and 46% at the dosage of 200 ug/mL, while the inhibitory rate of RPA50%-3 were 33%, 9%, and 1%, respectively. These results suggested that enzyme-extracted raspberry pectin contained more arabinan sidechains and exhibited better immunomodulatory effect.

A human-origin probiotic cocktail ameliorates aging-related leaky gut and inflammation via modulating the microbiota/taurine/tight junction axis.

Inflammation is a major risk factor of morbidity and mortality in older adults. Although its precise etiology is unknown, low-grade inflammation in older adults is commonly associated with increased intestinal epithelial permeability (leaky gut) and abnormal (dysbiotic) gut microbiota. The increasing older population and lack of treatments to reduce aging-related microbiota dysbiosis, leaky gut, and inflammation culminates in a rise in aging-related comorbidities, constituting a significant public health concern. Here, we demonstrate that a human-origin probiotic cocktail containing 5 Lactobacillus and 5 Enterococcus strains isolated from healthy infant gut prevented high-fat diet-induced (HFD-induced) microbiota dysbiosis, leaky gut, inflammation, metabolic dysfunctions, and physical function decline in older mice. Probiotic-modulated gut microbiota primarily reduced leaky gut by increasing tight junctions, which in turn reduced inflammation. Mechanistically, probiotics modulated microbiota in a way to increase bile salt hydrolase activity, which in turn increased taurine abundance in the gut that stimulated tight junctions and suppressed gut leakiness. Furthermore, in Caenorhabditis elegans, taurine increased life span, reduced adiposity and leaky gut, and enhanced physical function. The results suggest that such probiotic therapies could prevent or treat aging-related leaky gut and inflammation in the elderly.

Metformin Reduces Aging-Related Leaky Gut and Improves Cognitive Function by Beneficially Modulating Gut Microbiome/Goblet Cell/Mucin Axis.

Aging-related illnesses are increasing and effective strategies to prevent and/or treat them are lacking. This is because of a poor understanding of therapeutic targets. Low-grade inflammation is often higher in older adults and remains a key risk factor of aging-related morbidities and mortalities. Emerging evidence indicates that abnormal (dysbiotic) gut microbiome and dysfunctional gut permeability (leaky gut) are linked with increased inflammation in older adults. However, currently available drugs do not 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 Food and Drug Administration-approved antidiabetic drug, decreased leaky gut and inflammation in high-fat diet-fed older obese mice, by beneficially modulating the gut microbiota. In addition, metformin increased goblet cell mass and mucin production in the obese 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 be used as a regimen to prevent and treat aging-related leaky gut and inflammation, especially in obese individuals and people with western-style high-fat dietary lifestyle, by beneficially modulating gut microbiome/goblet cell/mucin biology.

Lipoteichoic acid from the cell wall of a heat killed Lactobacillus paracasei D3-5 ameliorates aging-related leaky gut, inflammation and improves physical and cognitive functions: from C. elegans to mice.

Increased inflammation associated with leaky gut is a major risk factor for morbidity and mortality in older adults; however, successful preventive and therapeutic strategies against these conditions are not available. In this study, we demonstrate that a human-origin Lactobacillus paracasei D3-5 strain (D3-5), even in the non-viable form, extends life span of Caenorhabditis elegans. In addition, feeding of heat-killed D3-5 to old mice (> 79 weeks) prevents high- fat diet-induced metabolic dysfunctions, decreases leaky gut and inflammation, and improves physical and cognitive functions. D3-5 feeding significantly increases mucin production, and proportionately, the abundance of mucin-degrading bacteria Akkermansia muciniphila also increases. Mechanistically, we show that the lipoteichoic acid (LTA), a cell wall component of D3-5, enhances mucin (Muc2) expression by modulating TLR-2/p38-MAPK/NF-kB pathway, which in turn reduces age-related leaky gut and inflammation. The findings indicate that the D3-5 and its LTA can prevent/treat age-related leaky gut and inflammation.

An In Vitro Batch-culture Model to Estimate the Effects of Interventional Regimens on Human Fecal Microbiota.

The emerging role of the gut microbiome in several human diseases demands a breakthrough of new tools, techniques and technologies. Such improvements are needed to decipher the utilization of microbiome modulators for human health benefits. However, the large-scale screening and optimization of modulators to validate microbiome modulation and predict related health benefits may be practically difficult due to the need for large number of animals and/or human subjects. To this end, in vitro or ex vivo models can facilitate preliminary screening of microbiome modulators. Herein, it is optimized and demonstrated an ex vivo fecal microbiota culture system that can be used for examining the effects of various interventions of gut microbiome modulators including probiotics, prebiotics and other food ingredients, aside from nutraceuticals and drugs, on the diversity and composition of the human gut microbiota. Inulin, one of the most widely studied prebiotic compounds and microbiome modulators, is used as an example here to examine its effect on the healthy fecal microbiota composition and its metabolic activities, such as fecal pH and the fecal levels of organic acids including lactate and short-chain fatty acids (SCFAs). The protocol may be useful for studies aimed at estimating the effects of different interventions of modulators on fecal microbiota profiles and at predicting their health impacts.

Prebiotics from acorn and sago prevent high-fat-diet-induced insulin resistance via microbiome-gut-brain axis modulation.

Role of gut microbiome in obesity and type 2 diabetes (T2D) became apparent from several independent studies indicating that gut microbiome modulators like prebiotics may improve microbiome perturbations (dysbiosis) to ameliorate metabolic derangements. We herein isolate water soluble, nondigestible polysaccharides from five plant-based foods (acorn, quinoa, sunflower, pumpkin seeds and sago) and assess their impact on human fecal microbiome and amelioration of high-fat-diet (HFD)-induced obesity/T2D in mice. During polysaccharide isolation, purification, biochemical and digestion resistance characterization, and fermentation pattern by human fecal microbiome, we select acorn- and sago-derived prebiotics (on the basis of relatively higher purity and yield and lower protein contamination) and examine their effects in comparison to inulin. Prebiotics treatments in human fecal microbiome culture system not only preserve microbial diversity but also appear to foster beneficial bacteria and short-chain fatty acids (SCFAs). Feeding of acorn- and sago-derived prebiotics ameliorates HFD-induced glucose intolerance and insulin resistance in mice, with effects comparatively superior to those seen in inulin-fed mice. Feeding of both of novel prebiotics as well as inulin increases SCFAs levels in the mouse gut. Interestingly, gut hyperpermeability and mucosal inflammatory markers were significantly reduced upon prebiotics feeding in HFD-fed mice. Hypothalamic energy signaling in terms of increased expression of pro-opiomelanocortin was also modulated by prebiotics administration. Results demonstrate that these (and/or such) novel prebiotics can ameliorate HFD-induced defects in glucose metabolism via positive modulation of gut-microbiome-brain axis and hence could be useful in preventing/treating diet-induced obesity/T2D.

Effects of different drying methods on the physicochemical properties and antioxidant activities of isolated acorn polysaccharides.

Our earlier studies showed that the Acorn Polysaccharides (AP), as a forest byproduct, have a good prebiotic properties and antioxidant activity, hence can be used as an ingredient to produce functional foods. Three drying methods (freeze, hot air and vacuum drying) in different temperatures were comparatively studied on the physicochemical properties (solubility, water and oil-holding capacity [OHC/WHC]), bioactivity (resistance to acidic and enzymatic digestions, effect on a probiotic strain growth) and antioxidant activity of AP along with the structural changes. Results suggest that the drying methods in combinations of temperatures and time of drying process affect physicochemical properties, antioxidant activity and bioactivities of AP. Freeze dried AP exhibited the highest solubility, WHC, OHC and antioxidant activity, digestibility with simulated gastrointestinal juices and fermentable by a Lactobacillus plantarum. Whereas, hot air dried (80 °C) exhibited second highest antioxidant and functional activities like solubility, WHC, OHC and fermentation. FTIR analysis showed that the changes caused by varying drying methods of AP starch are related to its amorphous or crystallinity structure and differences in functional group. Overall, these results suggest that freeze drying and hot air drying at 80 °C can be appropriately use to obtain a functional polysaccharide from acorn, as a prebiotic (resistant starch).

Microwave reflectometry for noninvasive imaging of skin abnormalities.

In this paper, a microwave microscope is presented for characterization of skin abnormalities. A coplanar waveguide probe is designed and fabricated for high-resolution near-field imaging of the biological samples. Several simulations and measurement studies are described to present the capability of the proposed probe in identification of different tissues and the detection of fat masses at different depths. In addition, two methods are used to eliminate the measurement noise which is caused by non-targeted tissues. Then, the contours around the masses are obtained applying an edge detection method. The measurement results show that the proposed probe can detect the fat masses with amplitude contrast about 15 dB at a λ/10 (at 14.36 GHz) standoff distance. The proposed microscope is easy to fabricate, and provides a low-cost solution for fast and accurate skin cancer detection of abnormalities in human body such as early detection of small tumors in breast or skin cancers.

Human-origin probiotic cocktail increases short-chain fatty acid production via modulation of mice and human gut microbiome.

The gut bacteria producing metabolites like short-chain fatty acids (SCFAs; e.g., acetate, propionate and butyrate), are frequently reduced in Patients with diabetes, obesity, autoimmune disorders, and cancers. Hence, microbiome modulators such as probiotics may be helpful in maintaining or even restoring normal gut microbiome composition to benefit host health. Herein, we developed a human-origin probiotic cocktail with the ability to modulate gut microbiota to increase native SCFA production. Following a robust protocol of isolation, characterization and safety validation of infant gut-origin Lactobacillus and Enterococcus strains with probiotic attributes (tolerance to simulated gastric and intestinal conditions, adherence to intestinal epithelial cells, absence of potential virulence genes, cell-surface hydrophobicity, and susceptibility to common antibiotics), we select 10 strains (5 from each genera) out of total 321 isolates. A single dose (oral gavage) as well as 5 consecutive doses of this 10-strain probiotic cocktail in mice modulates gut microbiome and increases SCFA production (particularly propionate and butyrate). Inoculation of these probiotics in human feces also increases SCFA production along with microbiome modulation. Results indicate that human-origin probiotic lactobacilli and enterococci could ameliorate gut microbiome dysbiosis and hence may prove to be a potential therapy for diseases involving reduced SCFAs production in the gut.

Gut microbiome and aging: Physiological and mechanistic insights.

The development of human gut microbiota begins as soon as the neonate leaves the protective environment of the uterus (or maybe in-utero) and is exposed to innumerable microorganisms from the mother as well as the surrounding environment. Concurrently, the host responses to these microbes during early life manifest during the development of an otherwise hitherto immature immune system. The human gut microbiome, which comprises an extremely diverse and complex community of microorganisms inhabiting the intestinal tract, keeps on fluctuating during different stages of life. While these deviations are largely natural, inevitable and benign, recent studies show that unsolicited perturbations in gut microbiota configuration could have strong impact on several features of host health and disease. Our microbiota undergoes the most prominent deviations during infancy and old age and, interestingly, our immune health is also in its weakest and most unstable state during these two critical stages of life, indicating that our microbiota and health develop and age hand-in-hand. However, the mechanisms underlying these interactions are only now beginning to be revealed. The present review summarizes the evidences related to the age-associated changes in intestinal microbiota and vice-versa, mechanisms involved in this bi-directional relationship, and the prospective for development of microbiota-based interventions such as probiotics for healthy aging.

Dietary Polysaccharides in the Amelioration of Gut Microbiome Dysbiosis and Metabolic Diseases.

The prevalence of metabolic diseases including obesity, diabetes, cardiovascular diseases, hypertension and cancer has evolved into a global epidemic over the last century. The rate of these disorders is continuously rising due to the lack of effective preventative and therapeutic strategies. This warrants for the development of novel strategies that could help in the prevention, treatment and/ or better management of such disorders. Although the complex pathophysiology of these metabolic diseases is one of the major hurdles in the development of preventive and/or therapeutic strategies, there are some factors that are or can speculated to be more effective to target than others. Recently, gut microbiome has emerged as one of the major contributing factors in metabolic diseases, and developing positive modulators of gut microbiota is being considered to be of significant interest. Natural non-digestible polysaccharides from plants and food sources are considered potent modulators of gut microbiome that can feed certain beneficial microbes in the gut. This has led to an increased interest in the isolation of novel bioactive polysaccharides from different plants and food sources and their application as functional components to modulate the gut microbiome composition to improve host's health including metabolism. Therefore, polysaccharides, as prebiotics components, are being speculated to confer positive effects in managing metabolic diseases like obesity and diabetes. In this review article, we summarize some of the most common polysaccharides from plants and food that impact metabolic health and discuss why and how these could be helpful in preventing or ameliorating metabolic diseases such as obesity, type 2 diabetes, hypertension and dyslipidemia.