Butyrate and other short-chain fatty acids as modulators of immunity: what relevance for health?

Short-Chain Fatty Acids and Lipopolysaccharide as Mediators Between Gut Dysbiosis and Amyloid Pathology in Alzheimer's Disease

BACKGROUND

Metagenomic data support an association between certain bacterial strains and Alzheimer's disease (AD), but their functional dynamics remain elusive.

OBJECTIVE

To investigate the association between amyloid pathology, bacterial products such as lipopolysaccharide (LPS) and short chain fatty acids (SCFAs: acetate, valerate, butyrate), inflammatory mediators, and markers of endothelial dysfunction in AD.

METHODS

Eighty-nine older persons with cognitive performance from normal to dementia underwent florbetapir amyloid PET and blood collection. Brain amyloidosis was measured with standardized uptake value ratio versus cerebellum. Blood levels of LPS were measured by ELISA, SCFAs by mass spectrometry, cytokines by using real-time PCR, and biomarkers of endothelial dysfunction by flow cytometry. We investigated the association between the variables listed above with Spearman's rank test.

RESULTS

Amyloid SUVR uptake was positively associated with blood LPS (rho≥0.32, p≤0.006), acetate and valerate (rho≥0.45, p < 0.001), pro-inflammatory cytokines (rho≥0.25, p≤0.012), and biomarkers of endothelial dysfunction (rho≥0.25, p≤0.042). In contrast, it was negatively correlated with butyrate (rho≤-0.42, p≤0.020) and the anti-inflammatory cytokine IL10 (rho≤-0.26, p≤0.009). Endothelial dysfunction was positively associated with pro-inflammatory cytokines, acetate and valerate (rho≥0.25, p≤0.045) and negatively with butyrate and IL10 levels (rho≤-0.25, p≤0.038).

CONCLUSION

We report a novel association between gut microbiota-related products and systemic inflammation with brain amyloidosis via endothelial dysfunction, suggesting that SCFAs and LPS represent candidate pathophysiologic links between the gut microbiota and AD pathology.

Gut microbiota restoration through fecal microbiota transplantation: a new atopic dermatitis therapy

The pathogenesis of atopic dermatitis (AD) involves complex factors, including gut microbiota and immune modulation, which remain poorly understood. The aim of this study was to restore gut microbiota via fecal microbiota transplantation (FMT) to ameliorate AD in mice. FMT was performed using stool from donor mice. The gut microbiota was characterized via 16S rRNA sequencing and analyzed using Quantitative Insights into Microbial Ecology 2 with the DADA2 plugin. Gut metabolite levels were determined by measuring fecal short-chain fatty acid (SCFA) contents. AD-induced allergic responses were evaluated by analyzing blood parameters (IgE levels and eosinophil percentage, eosinophil count, basophil percentage, and monocyte percentage), the levels of Th1 and Th2 cytokines, dermatitis score, and the number of mast cells in the ileum and skin tissues. Calprotectin level was measured to assess gut inflammation after FMT. FMT resulted in the restoration of gut microbiota to the donor state and increases in the levels of SCFAs as gut metabolites. In addition, FMT restored the Th1/Th2 balance, modulated Tregs through gut microbiota, and reduced IgE levels and the numbers of mast cells, eosinophils, and basophils. FMT is associated with restoration of gut microbiota and immunologic balance (Th1/Th2) along with suppression of AD-induced allergic responses and is thus a potential new therapy for AD.

Alterations of the Skin and Gut Microbiome in Psoriasis and Psoriatic Arthritis

Numerous scientific studies in recent years have shown significant skin and gut dysbiosis among patients with psoriasis. A significant decrease in microbiome alpha-diversity (abundance of different bacterial taxa measured in one sample) as well as beta-diversity (microbial diversity in different samples) was noted in psoriasis skin. It has been proven that the representation of Cutibacterium, Burkholderia spp., and Lactobacilli is decreased and Corynebacterium kroppenstedii, Corynebacterium simulans, Neisseria spp., and Finegoldia spp. increased in the psoriasis skin in comparison to healthy skin. Alterations in the gut microbiome in psoriasis are similar to those observed in patients with inflammatory bowel disease. In those two diseases, the F. prausnitzii, Bifidobacterium spp., Lactobacillus spp., Parabacteroides and Coprobacillus were underrepresented, while the abundance of Salmonella sp., Campylobacter sp., Helicobacter sp., Escherichia coli, Alcaligenes sp., and Mycobacterium sp. was increased. Several research studies provided evidence for the significant influence of psoriasis treatments on the skin and gut microbiome and a positive influence of orally administered probiotics on the course of this dermatosis. Further research is needed to determine the influence of the microbiome on the development of inflammatory skin diseases. The changes in microbiome under psoriasis treatment can serve as a potential biomarker of positive response to the administered therapy.

Going "Green" in the Prevention and Management of Atherothrombotic Diseases: The Role of Dietary Polyphenols

During the 20th century processed and ready-to-eat foods became routinely consumed resulting in a sharp rise of fat, salt, and sugar intake in people's diets. Currently, the global incidence of obesity, raised blood lipids, hypertension, and diabetes in an increasingly aged population contributes to the rise of atherothrombotic events and cardiovascular diseases (CVD) mortality. Drug-based therapies are valuable strategies to tackle and help manage the socio-economic impact of atherothrombotic disorders though not without adverse side effects. The inclusion of fresh fruits and vegetables rich in flavonoids to human diets, as recommended by WHO offers a valuable nutritional strategy, alternative to drug-based therapies, to be explored in the prevention and management of atherothrombotic diseases at early stages. Though polyphenols are mostly associated to color and taste in foods, food flavonoids are emerging as modulators of cholesterol biosynthesis, appetite and food intake, blood pressure, platelet function, clot formation, and anti-inflammatory signaling, supporting the health-promoting effects of polyphenol-rich diets in mitigating the impact of risk factors in atherothrombotic disorders and CVD events. Here we overview the current knowledge on the effect of polyphenols particularly of flavonoid intake on the atherothrombotic risk factors and discuss the caveats and challenges involved with current experimental cell-based designs.

Milk Consumption and Respiratory Function in Asthma Patients: NHANES Analysis 2007-2012

Per the Centers for Disease Control and Prevention, asthma prevalence has steadily risen since the 1980s. Using data from the National Health and Nutrition Examination Survey (NHANES), we investigated associations between milk consumption and pulmonary function (PF). Multivariable analyses were performed, adjusted for a priori potential confounders for lung function, within the eligible total adult population (n = 11,131) and those self-reporting asthma (n = 1,542), included the following variables: milk-consumption, asthma diagnosis, forced vital capacity (FVC), FVC%-predicted (%), forced expiratory volume in one-second (FEV1), FEV1% and FEV1/FVC. Within the total population, FEV1% and FVC% were significantly associated with regular (5+ days weekly) consumption of exclusively 1% milk in the prior 30-days (β:1.81; 95% CI: [0.297, 3.325]; p = 0.020 and β:1.27; [0.16, 3.22]; p = 0.046). Among participants with asthma, varied-regular milk consumption in a lifetime was significantly associated with FVC (β:127.3; 95% CI: [13.1, 241.4]; p = 0.002) and FVC% (β:2.62; 95% CI: [0.44, 4.80]; p = 0.006). No association between milk consumption and FEV1/FVC was found, while milk-type had variable influence and significance. Taken together, we found certain milk consumption tendencies were associated with pulmonary function values among normal and asthmatic populations. These findings propound future investigations into the potential role of dairy consumption in altering lung function and asthma outcomes, with potential impact on the protection and maintenance of pulmonary health.

Bacteroides thetaiotaomicron Ameliorates Experimental Allergic Airway Inflammation via Activation of ICOS+Tregs and Inhibition of Th2 Response

Inhibition of allergic airway diseases (AAD) by immunomodulation of the adaptive immune system through restoration of the enteric dysbiosis is an emerging therapeutic strategy. Patients with allergic rhinitis (n = 6) and healthy controls (n = 6) were enrolled, and gut microbiome composition analysis was performed by 16S rDNA sequencing. We also established an ovalbumin (OVA)-induced allergic airway inflammation murine model. Dysbiosis of the gut flora was observed in both AAD patients and the mice, with the decrease of the biodiversity and the quantity of the Bacteroidetes phylum. Oral application of Bacteroides (B.) thetaiotaomicron ameliorated the symptoms of OVA-induced airway hyperresponsiveness (AHR) and attenuated the airway inflammation in mice. In addition, nasal lavage fluid (NALF) and bronchoalveolar lavage fluid (BALF) from AAD mice orally administered with B. thetaiotaomicron showed reduced numbers of immune cells, and diminished secretion of T helper (Th)-2 cytokines (IL-4, IL-5, and IL-13) compared with the corresponding control mice, whereas the levels of Th1 cytokineIFN-γ was not changed in both the groups. When B. thetaiotaomicron was co-administered with metronidazole in AAD mice, the immunomodulatory effect was weakened and the allergic inflammatory response was aggravated. The ratios of CD4⁺Foxp3⁺ cells, CD4⁺ICOS⁺ T cells, CD4⁺ICOS⁺ Foxp3⁺ regulatory T cells, and IL-10-expressing CD4⁺Foxp3⁺ cells were increased in lymphocytes of spleen, mesenteric, and cervical lymph nodes of AAD mice administrated with B. thetaiotaomicron. Therefore, our data indicate that oral administration of B. thetaiotaomicron effectively inhibited the development of AAD in murine model; inhibition was mediated by the activation of Tregs and inhibition of Th2 response without promoting a Th1 response.

Diesel exhaust particles alter the profile and function of the gut microbiota upon subchronic oral administration in mice

BACKGROUND

Ambient air pollution by particulate matters, including diesel exhaust particles (DEP), is a major cause of cardiovascular and metabolic mortality worldwide. The mechanisms by which DEP cause these adverse outcomes are not completely understood. Because the gut microbiota controls cardiovascular and metabolic health, we hypothesized that the fraction of inhaled DEP which reach the gut after mucociliary clearance and swallowing might induce gut dysbiosis and, in turn, contribute to aggravate or induce cardiovascular and metabolic diseases.

RESULTS

Female ApoE^-/- mice fed a Western diet, and wild-type (C57Bl/6) mice fed standard diet were gavaged with DEP (SRM2975) doses corresponding to mucociliary clearance from inhalation exposure (200 or 1000 ng/day, 3 times a week for 3 months; and 40, 200 or 1000 ng/day, 3 times a week for 6 months, respectively). No mortality, overt systemic or digestive toxicity was observed. A dose-dependent alteration of the gut microbiota was recorded in both strains. In ApoE^-/-, β-diversity was modified by DEP, but no significant modification of the relative abundance of the phyla, families or genera was identified. In C57BL/6 mice, DEP reduced α-diversity (Shannon and Simpson indices), and modified β-diversity, including a reduction of the Proteobacteria and Patescibacteria phyla, and an increase of the Campylobacterota phylum. In both mouse models, perturbation of the gut microbiota composition was associated with a dose-dependent reduction of bacterial short chain fatty acids (butyrate and propionate) in cecal content. However, DEP ingestion did not aggravate (ApoE^-/-), or induce (C57BL/6 mice) atherosclerotic plaques, and no metabolic alteration (glucose tolerance, resistance to insulin, or lipidemia) was recorded.

CONCLUSIONS

We show here that oral exposure to DEP, at doses relevant for human health, changes the composition and function of the gut microbiota. These modifications were, however, not translated into ultimate atherosclerotic or metabolic outcomes.

Flexibility of Gut Microbiota in Ageing Individuals during Dietary Fiber Long-Chain Inulin Intake

SCOPE

During ageing, dysbiosis in the intestinal microbiota may occur and impact health. There is a paucity of studies on the effect of fiber on the elderly microbiota and the flexibility of the aged microbiota upon prebiotic intake. It is hypothesized that chicory long-chain inulin consumption can change microbiota composition, microbial fermentation products, and immunity in the elderly.

METHODS AND RESULTS

A double-blind, placebo-controlled trial is performed in healthy individuals (55-80 years), in which microbiota composition is studied before, during, and after two months of chicory long-chain inulin consumption. Fecal short chain fatty acid concentrations, T cell subsets, and antibody responses against a Hepatitis B (HB) vaccine are measured as well. Inulin consumption modified the microbiota composition, as measured by 16S rRNA sequencing. Participants consuming inulin have higher microbial diversity and a relatively higher abundance of the Bifidobacterium genus, as well as Alistipes shahii, Anaerostipes hadrus, and Parabacteroides distasonis. While the immune responses remain unchanged, the isobutyric acid levels, an undesired fermentation product, tend to be lower in the inulin group.

CONCLUSIONS

Overall, it is shown that the gut microbiota composition is still sensitive to chicory long-chain inulin induced changes in an ageing population, although this did not translate into an improved immune response to an HB vaccine.

Inverse association between dietary fiber intake and depression in premenopausal women: a nationwide population-based survey

OBJECTIVE

Depression is among the most common neuropsychiatric disorders, and its prevalence is twofold higher in women than in men. This study aimed to investigate the relationship between dietary fiber intake and depression in women by menopause status using data from a nationwide population-based survey conducted in Korea.

METHODS

We utilized the Korea National Health and Nutritional Examination Survey data for 2014, 2016, and 2018 with a complex sampling design. Dietary fiber intake was calculated according to the 24-hour recall method, and we used Patient Health Questionnaire-9 scores to assess depression. A t test based on the general linear model was used to compare mean dietary fiber intake according to the presence of depression by menopause status. A logistic regression analysis was conducted to compute the odds ratio for depression according to the gradually adjusted model.

RESULTS

This study included 5,807 women. Among the premenopausal women, dietary fiber intake was higher in the nondepression group than in the depression group (P < 0.001), while there was no significant difference among postmenopausal women. Accordingly, among the premenopausal women, a significantly inverse relationship was observed between a change in daily dietary fiber intake as 1 g/1,000 kcal and the prevalence of depression in the fully adjusted model with an odds ratio of 0.949 (95% confidence interval, 0.906-0.993; P = 0.03). However, among the postmenopausal women, this significant association was not observed.

CONCLUSIONS

Dietary fiber intake was inversely associated with depression in premenopausal but not postmenopausal women.

Skin and Gut Microbiome in Psoriasis: Gaining Insight Into the Pathophysiology of It and Finding Novel Therapeutic Strategies

Psoriasis affects the health of myriad populations around the world. The pathogenesis is multifactorial, and the exact driving factor remains unclear. This condition arises from the interaction between hyperproliferative keratinocytes and infiltrating immune cells, with poor prognosis and high recurrence. Better clinical treatments remain to be explored. There is much evidence that alterations in the skin and intestinal microbiome play an important role in the pathogenesis of psoriasis, and restoration of the microbiome is a promising preventive and therapeutic strategy for psoriasis. Herein, we have reviewed recent studies on the psoriasis-related microbiome in an attempt to confidently identify the “core” microbiome of psoriasis patients, understand the role of microbiome in the pathogenesis of psoriasis, and explore new therapeutic strategies for psoriasis through microbial intervention.

Metabolome-Based Analysis of Herbal Cough Preparations Via Headspace Solid-Phase Microextraction GC/MS and Multivariate Data Analyses: A Prospect for Its Essential Oil Equivalency

Liquid cough preparations containing essential oils pose a challenge for isolating and quantifying their volatile components from such a complex matrix enriched with nonvolatile constituents and excipients. This study aims to develop a strategy integrating QC analysis of seven natural cough preparations in the Egyptian market and to assess volatile variation among the preparations using multivariate data analyses. Cough preparations were subjected to headspace solid-phase microextraction (HS-SPME) for determination of their essential oil composition mediating for their actions and to assess volatile differences among them. HS-SPME is a suitable technique for sample preparation that allows for extraction and enrichment of volatiles from complex nonvolatile matrices and their direct desorption into the gas chromatography analytical system. A total of 88 volatile components were identified belonging to seven classes, viz. aromatics, aliphatic hydrocarbons, mono/sesquiterpene hydrocarbons, and oxygenated mono/sesquiterpenes. Oxygenated monoterpenes, viz., menthol, cineole, thymol, and (E)-anethole, were the major volatiles identified in five cough preparations (79.5-98.6%), whereas aromatics, chiefly cinnamate derivatives, constituted the second class amounting for 50.5 and 27.4% in the other two cough preparations. Meaningful results regarding the products' efficacy and safety were extrapolated from this analytical procedure, where artificial preservatives (parabens) were detected in five cough preparations. This study established an efficient strategy for exploring volatile profiling and defining different markers among the different cough preparations. Additionally, authenticity of listed herbal ingredients in the cough preparations was also confirmed in certain preparations, while other formulations failed to show representative volatile components. Volatile variation among preparations was assessed using multivariate data analyses in an attempt to prioritize cough preparations for usage, suggesting the preference of Bronchicum and Babetone among examined cough products.

The Gut Microbiota: How Does It Influence the Development and Progression of Liver Diseases

The gut–liver axis plays important roles in both the maintenance of a healthy liver and the pathogenesis of liver diseases, where the gut microbiota acts as a major determinant of this relationship. Gut bacteria-derived metabolites and cellular components are key molecules that affect the function of the liver and modulate the pathology of liver diseases. Accumulating evidence showed that gut microbiota produces a myriad of molecules, including lipopolysaccharide, lipoteichoic acid, peptidoglycan, and DNA, as well as short-chain fatty acids, bile acids, trimethylamine, and indole derivatives. The translocation of these components to the liver exerts beneficial or pathogenic effects by interacting with liver immune cells. This is a bidirectional relationship. Therefore, the existence of crosstalk between the gut and liver and its implications on host health and diseases are essential for the etiology and treatment of diseases. Several mechanisms have been proposed for the pathogenesis of liver diseases, but still, the mechanisms behind the pathogenic role of gut-derived components on liver pathogenesis remain elusive and not understandable. This review discusses the current progress on the gut microbiota and its components in terms of the progression of liver diseases, and in turn, how liver diseases indirectly affect the intestinal function and induce intestinal inflammation. Moreover, this paper highlights the current therapeutic and preventive strategies used to restore the gut microbiota composition and improve host health.

A longitudinal study reveals the alterations of the Microtus fortis colonic microbiota during the natural resistance to Schistosoma japonicum infection

The gut microbiota has been demonstrated to associate with protection against helminth infection and mediate via microbial effects on the host humoral immunity. As a non-permissive host of Schistosoma japonicum, the Microtus fortis provides an ideal animal model to be investigated, because of its natural self-healing capability. Although researches on the systemic immunological responses have revealed that the host immune system contributes a lot to the resistance, the role of gut microbiome remains unclear. In this study, we exposed the M. fortis to the S.japonicum infection, carried out a longitudinal research (uninfected control, infected for 7 days, 14 days, 21 days, and 31 days) on their colonic microbiota based on the 16S rRNA gene amplicon sequencing. The bacterial composition disclosed a disturbance-recovery alteration followed by the resistance to S. japonicum. The alpha diversity of colon microbiota was reduced after the infection, but it gradually recovered along with self-healing process. Further LEfSe analysis revealed that phyla shifted from Firmicutes to Bacteroidetes, which were mainly driven by an increase of Ruminococcaceae and a depletion of Muribaculaceae in the family level along the Control-Infection-Recovery (CIR) process. We identified a temporary blooming of Lactobacillaceae and Lactobacillus in the mid infection stage (D14). As a recognized probiotics repository, we speculate the increased abundance of Lactobacillaceae in M. fortis colonic microbiota might relate to the natural resistance to the schistosome. Besides, potential microbial functions were also significantly changed in the resistance process. These results demonstrate the remarkable alterations of reed vole colonic microbiota in both community structure and potential functions along with the resistance to S. japonicum infection. The identified microbial biomarkers might offer new ways for drug development to conquer human schistosomiasis.

Gut Microbiota and Immune System Interactions

Dynamic interactions between gut microbiota and a host’s innate and adaptive immune systems play key roles in maintaining intestinal homeostasis and inhibiting inflammation. The gut microbiota metabolizes proteins and complex carbohydrates, synthesize vitamins, and produce an enormous number of metabolic products that can mediate cross-talk between gut epithelial and immune cells. As a defense mechanism, gut epithelial cells produce a mucosal barrier to segregate microbiota from host immune cells and reduce intestinal permeability. An impaired interaction between gut microbiota and the mucosal immune system can lead to an increased abundance of potentially pathogenic gram-negative bacteria and their associated metabolic changes, disrupting the epithelial barrier and increasing susceptibility to infections. Gut dysbiosis, or negative alterations in gut microbial composition, can also dysregulate immune responses, causing inflammation, oxidative stress, and insulin resistance. Over time, chronic dysbiosis and the translocation of bacteria and their metabolic products across the mucosal barrier may increase prevalence of type 2 diabetes, cardiovascular disease, inflammatory bowel disease, autoimmune disease, and a variety of cancers. In this paper, we highlight the pivotal role gut microbiota and their metabolites (short-chain fatty acids (SCFAs)) play in mucosal immunity.

Modulation of the Microbiome in Parkinson's Disease: Diet, Drug, Stool Transplant, and Beyond

The gastrointestinal microbiome is altered in Parkinson's disease and likely plays a key role in its pathophysiology, affecting symptoms and response to therapy and perhaps modifying progression or even disease initiation. Gut dysbiosis therefore has a significant potential as a therapeutic target in Parkinson's disease, a condition elusive to disease-modifying therapy thus far. The gastrointestinal environment hosts a complex ecology, and efforts to modulate the relative abundance or function of established microorganisms are still in their infancy. Still, these techniques are being rapidly developed and have important implications for our understanding of Parkinson's disease. Currently, modulation of the microbiome can be achieved through non-pharmacologic means such as diet, pharmacologically through probiotic, prebiotic, or antibiotic use and procedurally through fecal transplant. Novel techniques being explored include the use of small molecules or genetically engineered organisms, with vast potential. Here, we review how some of these approaches have been used to date, important areas of ongoing research, and how microbiome modulation may play a role in the clinical management of Parkinson's disease in the future.

Sodium butyrate promotes lipopolysaccharide-induced innate immune responses by enhancing mitogen-activated protein kinase activation and histone acetylation in bovine mammary epithelial cells

The innate immune response plays a crucial role in recovery from infectious diseases by promoting the clearance of pathogens. Sodium butyrate (NaB) is an energy source for cellular processes with the potential to regulate the innate immune response. The present study aimed to evaluate the effect of NaB on the innate immune response in a bovine mammary alveolar cell line (MAC-T) initiated by lipopolysaccharides (LPS). Thus, treatments were conducted as follows: treated with 1× PBS for 24 h (control), pretreated with 1 mM NaB (optimized by cell viability assays and dose-dependent experiment) for 18 h followed by treatment of 1× PBS for 6 h (NaB), pretreated with 1× PBS for 18 h followed by stimulation with LPS (1 µg/mL) for 6 h (LPS), and pretreated with 1 mM NaB for 18 h followed by stimulation with LPS (1 µg/mL) for 6 h (NaB + LPS). Different inhibitors were also used to elucidate the underlying mechanism. Furthermore, cells were treated with NaB and heat-inactivated Escherichia coli to test the effect of NaB on transcription of genes related to the innate immune response triggered by the major causative pathogen of mastitis. Each treatment had 3 replicates and was repeated 3 times. Proinflammatory cytokines, chemokines, and β-defensins are crucial secretion factors in innate immunity, and transcription of these factors was increased by NaB during challenge with LPS or heat-inactivated E. coli in MAC-T cells. Acetylation of histone H3 protein, which promotes gene expression by affecting the structure of chromatin, was also upregulated by NaB in response to LPS stimulation. P38 mitogen-activated protein kinases (MAPK), JNK, and Erk 1 and 2 are key upstream regulators of the expression of proinflammatory cytokines, chemokines, and β-defensins, and their activity was enhanced by NaB during LPS stimulation. Furthermore, inhibitors were used to assess the role of MAPK signaling in the effects of NaB. The results showed that inhibitors of p38 MAPK, Erk, and JNK attenuated the NaB-induced upregulation of TNF and β-defensin 5 (DEFB5) transcription, and that the inhibitor of Erk attenuated the NaB-induced upregulation of IL1B transcription during LPS challenge. Enhanced transcription of CXCL8 by NaB was blocked by the inhibitor of Erk and p38 MAPK during LPS stimulation. Overall, NaB boosted the LPS-induced innate immune response by promoting the expression of proinflammatory cytokines, chemokines, and β-defensins, which was associated with enhanced MAPK signaling activation and histone H3 acetylation.

The Combinatorial Effect of Acetate and Propionate on High-Fat Diet Induced Diabetic Inflammation or Metaflammation and T Cell Polarization

High-fat diet (HFD) alters the gut microbiota and its fermentation products mainly acetate, propionate, and butyrate. Butyrate is well studied as a regulator of host metabolism and inflammation while acetate and propionate still need to be studied. Therefore, we aim to decipher the role of acetate and propionate alone and in combination in HFD-induced diabetic mice. HFD was given to mice for 4 months followed by treatment of butyrate, acetate, and propionate as well as acetate + propionate in combination for 1 month. Diabetic outcome was confirmed by evaluating fasting glucose, lipid profile, oral glucose tolerance test, % HbA1c, fasting insulin, and glucagon. To check the immune response, spleen and mesenteric lymph node-specific T cell polarization and serum cytokine profile were studied. HFD-fed mice showed increased body weight and diabetic characteristics while treatment with acetate and propionate regulated their levels in a healthy manner similar to butyrate. In HFD-fed mice, Th1 and Th17 cells were increased while Treg cells were decreased along with increased pro-inflammatory cytokines and decreased IL-10 in serum. The T cell polarization and cytokine profile was reversed by the treatment of acetate and propionate alone and in combination. Acetate reduced the levels of IL-1β and IL-6 and acetate + propionate reduced IL-6 more significantly than butyrate. Although, we did not find any synergistic effect in combination group, the results were better compared with acetate, propionate, and butyrate. In conclusion, acetate + propionate effectively reduced inflammation and improved insulin sensitivity in HFD-induced diabetic mice.

Analysis of the diversity of intestinal microbiome and its potential value as a biomarker in patients with schizophrenia: A cohort study

Exploring the gut microbiota characteristics of patients with acute and remission schizophrenia (SCZ) and evaluating the potential of the gut microbiome as a non-invasive biomarker for SCZ. A total of 87 fecal samples were collected, including a total of 58 samples from 29 SCZ patients over two different periods (remission and onset period) and 29 samples from the control group for 16S rRNA Miseq.The changes of intestinal microbiota in SCZ patients from remission to onset were analyzed, and a random forest model was constructed to recognize biomarkers. The optimal three genus-level diagnosis biomarkers were identified through an AUC validation on a random forest model, furthermore, an AUC of 0.76 (95% CI (0.63, 0.89)) was achieved between 29 aSCZ and 29 HCs. Compared with the control group, the first 11 OUT-level' biomarkers were identified in rSCZ group. As a status marker of the disease, the AUC of 0.7 (95% CI (0.56, 0.84)) was achieved between 29 rSCZ and 29 HCs. There were differences between SCZ patients and HCs, acute and remission patients as well, suggesting that the potential of the gut microbiota as a non-invasive diagnostic tool. Moreover, the features of the gut microbiome of SCZ provide clues for disease prognosis assessment and targeted intervention.

Long-Term Consumption of 2-O-β-d-Glucopyranosyl-l-ascorbic Acid from the Fruits of Lycium barbarum Modulates Gut Microbiota in C57BL/6 Mice

The modulating effect of 2-O-β-d-glucopyranosyl-l-ascorbic acid (AA-2βG), a natural derivative of ascorbic acid from the fruits of Lycium barbarum, on mice gut microbiota was investigated in the present study. It was found that AA-2βG was able to adjust the structure of mice gut microbiota, elevated the relative abundances of Verrucomicrobia, Porphyromonadaceae, Verrucomicrobiaceae, and Erysipelotrichaceae, and meanwhile reduced the relative abundances of Firmicutes, Lachnospiraceae, Rikenellaceae, Ruminococcaceae, Bdellovibrionaceae, Anaeroplasmataceae, and Peptococcaceae. Through the linear discriminant analysis effect size analysis, the key microbiota that were found to be significantly changed after long-term consumption of AA-2βG were Ruminococcaceae, Porphyromonadaceae, Lachnospiraceae, and Rikenellaceae. In addition, AA-2βG could upregulate pro-inflammatory cytokines, promote tight junctions between intestinal cells, facilitate the generation of short-chain fatty acids (SCFAs), and upregulate the mRNA expression level of SCFAs receptors, indicating that AA-2βG might promote organism health. The results demonstrated that AA-2βG might maintain organism health by modulating gut microbiota.

H. pylori Eradication Treatment Causes Alterations in the Gut Microbiota and Blood Lipid Levels

Background: The gut microbiome plays an important role in the lipid metabolism. Antibiotic treatment causes changes in the intestinal microbiota. Our objective was to explore the relationship between changes in the intestinal microbiota and the level of plasma high density lipoprotein cholesterol (HDL) and low density lipoprotein cholesterol (LDL).

Methods: Prospective case-control study with Helicobacter pylori-positive patients undergoing eradication therapy with omeprazole, clarithromycin, and amoxicillin. Stool and blood samples were obtained from 20 controls (H. pylori negative) and 40 patients before and 2 months after antibiotic treatment. Gut microbiota was determined through 16S rRNA amplicon sequencing (Illumina MiSeq).

Results: Eradication treatment for H. pylori increased the HDL levels, and caused changes in gut microbiota profiles. An unfavorable lipid profiles (high LDL and low HDL levels) was associated with a low microbial richness and an increase of the Bacteroidetes phylum. Prevotella copri, Lachonobacterium, and Delsufovibrio were positively associated with HDL while Rikenellaceae was negatively associated with HDL after completing antibiotic treatment.

Conclusions:Helicobacter pylori eradication treatment could improve lipid metabolism in relation with an increase in the HDL. Changes in the abundance of specific bacteria, such as P. copri, Lachonobacterium, Delsufovibrio, and Rikenellaceae could be associated with change in the plasma HDL levels.

Analysis of resorbable mesh implants in short-term human muscular fascia cultures: a pilot study

PURPOSE

Alteration in fascial tissue collagen composition represents a key factor in hernia etiology and recurrence. Both resorbable and non-resorbable meshes for hernia repair are currently used in the surgical setting. However, no study has investigated so far the role of different implant materials on collagen deposition and tissue remodeling in human fascia. The aim of the present study was to develop a novel ex vivo model of human soft tissue repair mesh implant, and to test its suitability to investigate the effects of different materials on tissue remodeling and collagen composition.

METHODS

Resorbable poly-4-hydroxybutyrate and non-resorbable polypropylene mesh implants were embedded in human abdominal fascia samples, mimicking common surgical procedures. Calcein-AM/Propidium Iodide vital staining was used to assess tissue vitality. Tissue morphology was evaluated using Mallory trichrome and hematoxylin and eosin staining. Collagen type I and III expression was determined through immunostaining semi-quantification by color deconvolution. All analyses were performed after 54 days of culture.

RESULTS

The established ex vivo model showed good viability at 54 days of culture, confirming both culture method feasibility and implants biocompatibility. Both mesh implants induced a disorganization of collagen fibers pattern. A statistically significantly higher collagen I/III ratio was detected in fascial tissue samples cultured with resorbable implants compared to either non-resorbable implants or meshes-free controls.

CONCLUSION

We developed a novel ex vivo model and provided evidence that resorbable polyhydroxybutyrate meshes display better biomechanical properties suitable for proper restoration in surgical hernia repair.

Liver Cirrhosis and Sarcopenia from the Viewpoint of Dysbiosis

Sarcopenia in patients with liver cirrhosis (LC) has been attracting much attention these days because of the close linkage to adverse outcomes. LC can be related to secondary sarcopenia due to protein metabolic disorders and energy metabolic disorders. LC is associated with profound alterations in gut microbiota and injuries at the different levels of defensive mechanisms of the intestinal barrier. Dysbiosis refers to a state in which the diversity of gut microbiota is decreased by decreasing the bacterial species and the number of bacteria that compose the gut microbiota. The severe disturbance of intestinal barrier in LC can result in dysbiosis, several bacterial infections, LC-related complications, and sarcopenia. Here in this review, we will summarize the current knowledge of the relationship between sarcopenia and dysbiosis in patients with LC.

Gut-organ axis: a microbial outreach and networking

Human gut microbiota (GM) includes a complex and dynamic population of microorganisms that are crucial for well-being and survival of the organism. It has been reported as diverse and relatively stable with shared core microbiota, including Bacteroidetes and Firmicutes as the major dominants. They are the key regulators of body homeostasis, involving both intestinal and extra-intestinal effects by influencing many physiological functions such as metabolism, maintenance of barrier homeostasis, inflammation and hematopoiesis. Any alteration in GM community structures not only trigger gut disorders but also influence other organs and cause associated diseases. In recent past, the GM has been defined as a 'vital organ' with its involvement with other organs; thus, establishing a link or a bi- or multidirectional communication axis between the organs via neural, endocrine, immune, humoral and metabolic pathways. Alterations in GM have been linked to several diseases known to humans; although the exact interaction mechanism between the gut and the organs is yet to be defined. In this review, the bidirectional relationship between the gut and the vital human organs was envisaged and discussed under several headings. Furthermore, several disease symptoms were also revisited to redefine the communication network between the gut microbes and the associated organs.

Interactions of dietary polyphenols with epithelial lipids: advances from membrane and cell models in the study of polyphenol absorption, transport and delivery to the epithelium

Currently, diet-related diseases such as diabetes, obesity, hypertension, and cardiovascular diseases account for 70% of all global deaths. To counteract the rising prevalence of non-communicable diseases governments are investing in persuasive educational campaigns toward the ingestion of fresh fruits and vegetables. The intake of dietary polyphenols abundant in Mediterranean and Nordic-type diets holds great potential as nutritional strategies in the management of diet-related diseases. However, the successful implementation of healthy nutritional strategies relies on a pleasant sensory perception in the mouth able to persuade consumers to adopt polyphenol-rich diets and on a deeper understanding on the chemical modifications, that affect not only their chemical properties but also their physical interaction with epithelial lipids and in turn their permeability, location within the lipid bilayer, toxicity and biological activity, and fate during absorption at the gastro-intestinal epithelium, transport in circulation and delivery to the endothelium. In this paper, we review the current knowledge on the interactions between polyphenols and their metabolites with membrane lipids in artificial membranes and epithelial cell models (oral, stomach, gut and endothelium) and the findings from polyphenol-lipid interactions to physiological processes such as oral taste perception, gastrointestinal absorption and endothelial health. Finally, we discuss the limitations and challenges associated with the current experimental approaches in membrane and cell model studies and the potential of polyphenol-rich diets in the quest for personalized nutritional strategies ("personalized nutrition") to assist in the prevention, treatment, and management of non-communicable diseases in an increasingly aged population.

Intestinal Flora as a Potential Strategy to Fight SARS-CoV-2 Infection

The coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has spread rapidly worldwide, seriously endangering human health. In addition to the typical symptoms of pulmonary infection, patients with COVID-19 have been reported to have gastrointestinal symptoms and/or intestinal flora dysbiosis. It is known that a healthy intestinal flora is closely related to the maintenance of pulmonary and systemic health by regulating the host immune homeostasis. Role of the "gut-lung axis" has also been well-articulated. This review provides a novel suggestion that intestinal flora may be one of the mediators of the gastrointestinal responses and abnormal immune responses in hosts caused by SARS-CoV-2; improving the composition of intestinal flora and the proportion of its metabolites through probiotics, and personalized diet could be a potential strategy to prevent and treat COVID-19. More clinical and evidence-based medical trials may be initiated to determine the strategy.

Comparative assessment of faecal microbial composition and metabonome of swine, farmers and human control

The gastrointestinal tract of humans and swine consist of a wide range of bacteria which interact with hosts metabolism. Due to the differences in co-evolution and co-adaptation, a large fraction of the gut microbiome is host-specific. In this study, we evaluated the effect of close human-animal interaction to the faecal metagenome and metabonome of swine, farmer and human control. Three distinct clusters were observed based on T-RFLP-derived faecal microbial composition. However, 16S-inferred faecal microbiota and metabolic profiles showed that only human control was significantly different from the swine (P < 0.05). The metabonome of farmers and human controls were highly similar. Notably, higher trimethylamine N-oxide (TMAO) and butyrate were detected in human control and swine, respectively. The relative abundance of TMAO was positively correlated with Prevotella copri. Overall, we compared and established the relationship between the metabolites and microbiota composition of swine, farmers and human control. Based on the data obtained, we deduced that long term occupational exposure to swine and farm environment had affected the gut bacterial composition of farmers. Nonetheless, the effect was less prominent in the metabolite profiles, suggesting the gut bacteria expressed high functional plasticity and are therefore resilience to the level of community shift detected.

Amoxicillin-induced gut dysbiosis influences estrous cycle in mice and cytokine expression in the ovary and the caecum

PROBLEM

Gut dysbiosis is caused by several factors, including the use of antibiotics. Since intestinal dysbiosis is associated with a wide range of immunopathological and reproductive conditions, the main goal of this study was to evaluate amoxicillin-induced gut dysbiosis and its influence on the oestrous cycle in mice.

METHOD OF STUDY

Mice were treated with amoxicillin or PBS, and faecal microbiota was evaluated by 16S rDNA metagenomic sequencing. The oestrous cycle was evaluated by vaginal cytology, vaginal opening and flow cytometry. After the induction of gut dysbiosis, the ovaries and the caecum were analysed to differential expression of IL-1β and IL-10 genes and histological analysis.

RESULTS

Amoxicillin-treated mice presented differing bacterial groups in the faecal microbiota when compared to the PBS-treated group indicating that amoxicillin treatment-induced gut dysbiosis and they gained weight. The vaginal cytology analysis showed that amoxicillin-induced gut dysbiosis decreased the number of cells but increased the relative number of leucocytes and altered the oestrous cycle. IL-1β was shown to be upregulated in the caecum and in the ovary of the dysbiotic mice. On the other hand, IL-10 expression was shown to be diminished in both organs of the dysbiotic mice. The oocyte area from dysbiotic group presented lower than non-dysbiotic mice with increasing thickness of the pellucid zone. The follicular teak from dysbiotic mice showed lower thickness than non-dysbiotic mice.

CONCLUSION

The results indicate that amoxicillin induces gut dysbiosis and influences the oestrous cycle and the inflammatory status of the ovary and the caecum.

Systemic short chain fatty acids limit antitumor effect of CTLA-4 blockade in hosts with cancer

Gut microbiota composition influences the clinical benefit of immune checkpoints in patients with advanced cancer but mechanisms underlying this relationship remain unclear. Molecular mechanism whereby gut microbiota influences immune responses is mainly assigned to gut microbial metabolites. Short-chain fatty acids (SCFA) are produced in large amounts in the colon through bacterial fermentation of dietary fiber. We evaluate in mice and in patients treated with anti-CTLA-4 blocking mAbs whether SCFA levels is related to clinical outcome. High blood butyrate and propionate levels are associated with resistance to CTLA-4 blockade and higher proportion of Treg cells. In mice, butyrate restrains anti-CTLA-4-induced up-regulation of CD80/CD86 on dendritic cells and ICOS on T cells, accumulation of tumor-specific T cells and memory T cells. In patients, high blood butyrate levels moderate ipilimumab-induced accumulation of memory and ICOS + CD4 + T cells and IL-2 impregnation. Altogether, these results suggest that SCFA limits anti-CTLA-4 activity.

The gut microbiota has been reported to regulate the efficacy of cancer therapy. Here, the authors show that short-chain fatty acids, which are generated through bacterial fermentation, increases immune tolerance leading to resistance to anti-CTLA-4 immunotherapy in mice and patients with metastatic melanoma.

The Role of Gut Dysbiosis in the Bone-Vascular Axis in Chronic Kidney Disease

Patients with chronic kidney disease (CKD) are at increased risk of bone mineral density loss and vascular calcification. Bone demineralization and vascular mineralization often concur in CKD, similar to what observed in the general population. This contradictory association is commonly referred to as the 'calcification paradox' or the bone-vascular axis. Mounting evidence indicates that CKD-associated gut dysbiosis may be involved in the pathogenesis of the bone-vascular axis. A disrupted intestinal barrier function, a metabolic shift from a predominant saccharolytic to a proteolytic fermentation pattern, and a decreased generation of vitamin K may, alone or in concert, drive a vascular and skeletal pathobiology in CKD patients. A better understanding of the role of gut dysbiosis in the bone-vascular axis may open avenues for novel therapeutics, including nutriceuticals.

Probiotics with ameliorating effects on the severity of skin inflammation in psoriasis: Evidence from experimental and clinical studies

Experimental and clinical studies have confirmed safety and the medical benefits of probiotics as immunomodulatory medications. Recent advances have emphasized the critical effect of gastrointestinal bacteria in the pathology of inflammatory disorders, even, outside the gut. Probiotics have shown promising results for curing skin-influencing inflammatory disorders through modulating the immune response by manipulating the gut microbiome. Psoriasis is a complex inflammatory skin disease, which exhibits a microbiome distinct from the normal skin. In the present review, we considered the impact of gastrointestinal microbiota on the psoriasis pathogenesis, and through literature survey, attempted to explore probiotic species utilized for psoriasis treatment.

Deuteration of the farnesyl terminal methyl groups of δ-tocotrienol and its effects on the metabolic stability and ability of inducing G-CSF production

δ-tocotrienol (DT3), a member of vitamin E family, has been shown to have a potent radio-protective effect. However, its application as a radioprotectant is limited, at least in part, by its short plasma elimination half-life and low bioavailability. In an effort to increase the metabolic stability of DT3, a deuterium substituted DT3 derivative, d₆-DT3, was designed and synthesized. d₆-DT3 showed improved in vitro and in vivo metabolic stability compared to DT3. The unexpected lower potency of d₆-DT3 in inducing granulocyte-colony stimulating factor (G-CSF) production in mouse revealed that the metabolite(s) of DT3 might play a major role in inducing G-CSF induction.

Acetate and Butyrate Improve β-cell Metabolism and Mitochondrial Respiration under Oxidative Stress

Islet dysfunction mediated by oxidative and mitochondrial stress contributes to the development of type 1 and 2 diabetes. Acetate and butyrate, produced by gut microbiota via fermentation, have been shown to protect against oxidative and mitochondrial stress in many cell types, but their effect on pancreatic β-cell metabolism has not been studied. Here, human islets and the mouse insulinoma cell line MIN6 were pre-incubated with 1, 2, and 4 mM of acetate or butyrate with and without exposure to the apoptosis inducer and metabolic stressor streptozotocin (STZ). Both short-chain fatty acids (SCFAs) enhanced the viability of islets and β-cells, but the beneficial effects were more pronounced in the presence of STZ. Both SCFAs prevented STZ-induced cell apoptosis, viability reduction, mitochondrial dysfunction, and the overproduction of reactive oxygen species (ROS) and nitric oxide (NO) at a concentration of 1 mM but not at higher concentrations. These rescue effects of SCFAs were accompanied by preventing reduction of the mitochondrial fusion genes MFN, MFN2, and OPA1. In addition, elevation of the fission genes DRP1 and FIS1 during STZ exposure was prevented. Acetate showed more efficiency in enhancing metabolism and inhibiting ROS, while butyrate had less effect but was stronger in inhibiting the SCFA receptor GPR41 and NO generation. Our data suggest that SCFAs play an essential role in supporting β-cell metabolism and promoting survival under stressful conditions. It therewith provides a novel mechanism by which enhanced dietary fiber intake contributes to the reduction of Western diseases such as diabetes.

Topical Application of Adult Cecal Contents to Eggs Transplants Spore-Forming Microbiota but Not Other Members of the Microbiota to Chicks

The intestinal microbiota plays an essential role in the metabolism and immune competence of chickens from the first day after hatching. In modern production systems, chicks are isolated from adult chickens, instead hatching in a clean environment. As a result, chicks are colonized by environmental bacteria, including potential pathogens. There is a need to investigate methods by which chicks can be exposed to a more appropriate microbial community at hatching. Such methods must be easy to apply in a hatchery and produce consistent results. The development of the intestinal microbiota of chicks hatched from eggs sprayed with dilute adult cecal content during incubation was observed at 0, 3, 7, and 14 days posthatching (dph) across two experiments. High-throughput Illumina sequencing was performed for the V4 hypervariable region of the 16S rRNA gene. A topical treatment of dilute adult cecal content was sufficient to transplant spore-forming bacteria such as Lachnospiraceae and Ruminococcaceae However, this treatment was not able to transplant other taxa that are considered to be core elements of the chicken cecal microbiota, such as Bacteroidaceae, Lactobacillaceae, Bifidobacteriaceae, and Burkholderiaceae The topical treatment significantly altered the microbiota of chicks immediately posthatching and accelerated the normal development of the microbiota with earlier colonization by Ruminococcaceae in the cecum and "Candidatus Arthromitus" in the ileum. The effect of the treatment on the cecal microbiota was maximal at 3 dph but diminished over time.IMPORTANCE Over the last 60 years poultry production has intensified in response to increased demand for meat. In modern systems, chicks hatch without contacting chickens and their gut bacteria. Consequently, they are colonized by environmental bacteria that may cause disease. The normal bacteria that live in the gut, or intestinal microbiota, play an important role in the development of the immune system. Therefore, it is essential to find easy ways to expose chicks to the more appropriate bacteria at hatching. This experiment investigated whether spraying eggs with adult cecal contents was sufficient to transfer an adult microbiota to chicks. Our findings show that spore-forming bacteria were transplanted, but other members of the microbiota were not. In this respect, the spray application was partially successful, but the timing of the spray needs to be modified to ensure that more bacteria are transferred.

Protective effect of sodium propionate in Aβ1-42 -induced neurotoxicity and spinal cord trauma

Sodium propionate (SP) is one of the main short chain fatty acids (SCFA) that can be produced naturally through host metabolic pathways. SP have been documented and include the reduction of pro-inflammatory mediators in an in vivo model of colitis. The aim of this study is to evaluate the neuroprotective effects of SP in reducing inflammatory process associated to neurological disorders. We performed both in vitro model of Alzheimer's disease, induced by oligomeric Aβ_1-42 stimulation, and in in vivo model of spinal cord injury (SCI) in which neuroinflammation plays a crucial role. For in vitro model, the human neuroblastoma SH-SY5Y cell line was first differentiated with retinoic acid (100 μM) for 24 h and then stimulated by oligomeric Aβ_1-42 (1 μg/ml) and treated with SP at 0.1- 1-10 μM concentrations for another 24 h. Instead, the in vivo model of SCI was induced by extradural compression of the spinal cord at T6-T8 levels, and animals were treated with SP (10-30-100 mg/kg o.s) 1 and 6 h after SCI. Our results demonstrated that both in in vitro neuroinflammatory model and in vivo model of SCI the treatment with SP significantly reduced NF-κB nuclear translocation and IκBα degradation, as well as decreases COX-2 and iNOS expressions evaluated by Western blot analysis. Moreover, we showed that SP treatment significantly ameliorated histopathology changes and improved motor recovery in a dose-dependent manner. In conclusion, our results demonstrated that SP possesses neuroprotective effects, suggesting it could represent a target for therapeutic intervention in neuroinflammatory disorders.

Skin Cutibacterium acnes Mediates Fermentation to Suppress the Calcium Phosphate-Induced Itching: A Butyric Acid Derivative with Potential for Uremic Pruritus

Pruritus and inflammation associated with accumulation of calcium phosphate (CaP) under the skin are common problems among dialysis patients with chronic kidney disease (CKD). The role of skin commensal microbiota in the CaP-induced uremic pruritus remains uncharacterized. Skin Cutibacterium acnes (C. acnes) can solubilize CaP by the production of short-chain fatty acids (SCFAs), such as butyric acid, through glucose fermentation. Like butyric acid, the N-[2-(2-Butyrylamino-ethoxy)-ethyl]-butyramide (BA-NH-NH-BA), a butyric acid derivative, remarkably induced acetylation of histone H3 lysine 9 (AcH3K9) in keratinocytes. Topical application of fermenting C. acnes, butyric acid or BA-NH-NH-BA onto mouse skin effectively ameliorated CaP-induced skin itching, interleukin (IL)-6 up-regulation in keratinocytes, and extracellular signal-regulated kinase (ERK) 1/2 activation in dorsal root ganglia (DRG). Activation of ERK 1/2 by CaP was markedly reduced in IL-6 knockout mice. Genus Cutibacterium was detected in relatively low abundance in itchy skin of patients with CKD. Our results identify a role for the skin fermenting C. acnes in ameliorating CaP-induced activation of IL-6/p-ERK signaling and resulting skin inflammation. Furthermore, we provide evidence for the potential therapeutic efficacy of BA-NH-NH-BA as a postbiotic for the treatment of uremic pruritus.

Exploring the Benefit of 2-Methylbutyric Acid in Patients Undergoing Hemodialysis Using a Cardiovascular Proteomics Approach

Short-chain fatty acids (SCFAs) can reduce pro-inflammatory parameters and oxidative stress, providing potential cardiovascular (CV) benefits. Although some evidence links SCFAs with host metabolic health via several biological mechanisms, the role of SCFA on CV disease in patients with kidney disease remains unclear. Herein, we investigate the association between a SCFA, 2-methylbutyric acid, and target CV proteomics to explore the potential pathophysiology of SCFA-related CV benefit in patients with kidney disease. Circulating 2-methylbutyric acid was quantified by high-performance liquid chromatography and 181 CV proteins by a proximity extension assay in 163 patients undergoing hemodialysis (HD). The associations between 2-methylbutyric acid and CV proteins were evaluated using linear regression analysis with age and gender, and multiple testing adjustment. The selected CV protein in the discovery phase was further confirmed in multivariable-adjusted models and evaluated by continuous scale association. The mean value of circulating 2-methylbutyric acid was 0.22 ± 0.02 µM, which was negatively associated with bone morphogenetic protein 6 (BMP-6) according to the false discovery rate (FDR) multiple testing adjustment method. The 2-methylbutyric acid level remained negatively associated with BMP-6 (β coefficient -1.00, 95% confidence interval -1.45 to -0.55, p < 0.001) after controlling for other CV risk factors in multivariable models. The cubic spline curve demonstrated a linear relationship. In conclusion, circulating 2-methylbutyric acid level was negatively associated with BMP-6, suggesting that this pathway maybe involved in vascular health in patients undergoing HD. However, further in vitro work is still needed to validate the translation of the mechanistic pathways.

Invariant NKT Cells Functionally Link Microbiota-Induced Butyrate Production and Joint Inflammation

Emerging evidence indicates that the gut microbiota contributes to the regulation of joint inflammation by modulating the function of immune cells. However, the mechanism by which the microbiota regulates joint inflammation is unclear. To address this, we investigated the effect of the gut microbiota on Ab-induced arthritis (AIA). Feeding mice a high-fiber diet attenuated AIA in a microbiota-dependent manner. Among the short-chain fatty acids produced by the microbiota, butyrate suppressed cytokine production by invariant NKT (iNKT) cells by inhibiting class I histone deacetylases. Furthermore, butyrate alleviated AIA in wild-type, but not iNKT cell-deficient Jα18 knockout (KO), mice. Adoptive transfer of butyrate-pretreated iNKT cells had no effect on AIA in Jα18 KO mice, whereas transfer of untreated iNKT cells into Jα18 KO mice restored AIA. In conclusion, our data indicate that gut microbiota-induced butyrate production attenuates AIA by inhibiting cytokine production by iNKT cells. Thus, the microbiota/butyrate/iNKT cell axis may be a therapeutic target for joint inflammation.

The role of gut microbiome in the pathogenesis of psoriasis and the therapeutic effects of probiotics

The adult intestine hosts a huge number of diverse bacterial species, collectively referred to as the microbiome, that reside mainly in the lower gut, where they maintain a symbiotic relationship with their host. Recent research points to a central role of the microbiome in many biological processes. These microbial communities are influenced by multiple environmental and dietary factors and can modulate immune responses. In addition to local effects on the gastrointestinal tract, the microbiota is associated with effects on other organs and tissues, such as the skin. Indeed, an altered microbiome has been associated with skin disorders in several instances. Thus, in this review, we describe the recent advances regarding the interplay between gut microbiota and the skin. We explore how this potential link affects skin homeostasis and its influence on modulating the cutaneous immune response, focusing on psoriasis disorder. Finally, we discuss how to take advantage of this interplay to manage this disorder, particularly through probiotics administration. In the gastrointestinal tract, the microbiome has been proven to be important in the maintenance of the balance between effector T cells and regulatory T cells, and the induction of immunoglobulin A. Moreover, gut bacterial dysbiosis is associated with chronic inflammatory disorders of the skin, such as psoriasis. Thus, the microbiome can be considered an effective therapeutical target for treating this disorder. Despite some limitations, interventions with probiotics seem promising for the development of a preventive therapy by restoring altered microbiome functionality or as an adjuvant in specific immunotherapy.

Effect of agave fructans on the production of short chain fatty acid in mice

The aim of this study was to evaluate the effect of agave fructans on short chain fatty acid (SCFA) production in mice (C57BL/6). Animals were randomly divided into three groups (n = 8): control group (CG), fructans from Agave tequilana group (FG) (55 g per day/kg of body weight), and oligrofructose group (OG) (55 g per day/kg of body weight). Treatments were administered oral via for 6 weeks. After 24 days of treatment (phase 1), both treated groups exhibited elevated levels of acetic (12%) and propionic (FG 66% and OG 38%) acids in comparison with the CG. After 42 days of treatment (phase 2), FG had higher concentrations of acetic (33%) and propionic (73%) acids than the CG; while OG exhibited higher levels of butyric (12%) and propionic (35%) acids compared with the CG. Fructans from Agave tequilana improve the production of SCFA in mice, suggesting a prebiotic activity.

A Fermented Food Product Containing Lactic Acid Bacteria Protects ZDF Rats from the Development of Type 2 Diabetes

Type 2 diabetes (T2D) is a complex metabolic disease, which involves a maintained hyperglycemia due to the development of an insulin resistance process. Among multiple risk factors, host intestinal microbiota has received increasing attention in T2D etiology and progression. In the present study, we have explored the effect of long-term supplementation with a non-dairy fermented food product (FFP) in Zucker Diabetic and Fatty (ZDF) rats T2D model. The supplementation with FFP induced an improvement in glucose homeostasis according to the results obtained from fasting blood glucose levels, glucose tolerance test, and pancreatic function. Importantly, a significantly reduced intestinal glucose absorption was found in the FFP-treated rats. Supplemented animals also showed a greater survival suggesting a better health status as a result of the FFP intake. Some dissimilarities have been observed in the gut microbiota population between control and FFP-treated rats, and interestingly a tendency for better cardiometabolic markers values was appreciated in this group. However, no significant differences were observed in body weight, body composition, or food intake between groups. These findings suggest that FFP induced gut microbiota modifications in ZDF rats that improved glucose metabolism and protected from T2D development.

The Role of Butyrate on Monocyte Migration and Inflammation Response in Patient with Type 2 Diabetes Mellitus

Type 2 Diabetes Mellitus (T2DM) is a very serious global problem. In Indonesia, this disease attacks at the most productive age; consequently, it can reduce economic status and life expectancy. The pathogenesis of T2DM is very closely related to inflammation and macrophage accumulation. However, no anti-inflammatory agent has been proven to play a role in the management of T2DM. Butyrate is a short chain fatty acid produced from resistant starch fermentation in the intestinal lumen. It is able to bind to GPR41 and GPR43 receptors on monocytes, so that it can change the pattern of cytokine expression, activation, migration and cell differentiation. Hence, it is interesting to examine the anti-inflammation effect of butyrate and the effect on monocyte migration. A total of 37 subjects were examined in this study. They were divided into two groups, with and without butyrate treatment. We analyzed two pro-inflammatory cytokines (Tumor Necrosis Factor TNF-α and Interleukin IL-6) and one anti-inflammatory cytokine, IL 10. Monocytes were isolated in type 1 collagen gel for migration testing using the µ-slide chemotaxis IBIDI. Image analysis used ImageJ and Chemotaxis tool software. There was a significant difference in the TNFα/IL 10 ratio between healthy groups and T2DM. Butyrate also appears to suppress TNFα cytokine production and increase IL10 production. It also decreases the accumulation distance of monocyte migration in T2DM.

Butyric Acid from Probiotic Staphylococcus epidermidis in the Skin Microbiome Down-Regulates the Ultraviolet-Induced Pro-Inflammatory IL-6 Cytokine via Short-Chain Fatty Acid Receptor

The glycerol fermentation of probiotic Staphylococcus epidermidis (S. epidermidis) in the skin microbiome produced butyric acid in vitro at concentrations in the millimolar range. The exposure of dorsal skin of mice to ultraviolet B (UVB) light provoked a significant increased production of pro-inflammatory interleukin (IL)-6 cytokine. Topical application of butyric acid alone or S. epidermidis with glycerol remarkably ameliorated the UVB-induced IL-6 production. In vivo knockdown of short-chain fatty acid receptor 2 (FFAR2) in mouse skin considerably blocked the probiotic effect of S. epidermidis on suppression of UVB-induced IL-6 production. These results demonstrate that butyric acid in the metabolites of fermenting skin probiotic bacteria mediates FFAR2 to modulate the production of pro-inflammatory cytokines induced by UVB.

Association of dietary fibre intake and gut microbiota in adults

Increasing evidence indicates that gut microbiota may influence colorectal cancer risk. Diet, particularly fibre intake, may modify gut microbiota composition, which may affect cancer risk. We investigated the relationship between dietary fibre intake and gut microbiota in adults. Using 16S rRNA gene sequencing, we assessed gut microbiota in faecal samples from 151 adults in two independent study populations: National Cancer Institute (NCI), n 75, and New York University (NYU), n 76. We calculated energy-adjusted fibre intake based on FFQ. For each study population with adjustment for age, sex, race, BMI and smoking, we evaluated the relationship between fibre intake and gut microbiota community composition and taxon abundance. Total fibre intake was significantly associated with overall microbial community composition in NYU (P=0·008) but not in NCI (P=0·81). In a meta-analysis of both study populations, higher fibre intake tended to be associated with genera of class Clostridia, including higher abundance of SMB53 (fold change (FC)=1·04, P=0·04), Lachnospira (FC=1·03, P=0·05) and Faecalibacterium (FC=1·03, P=0·06), and lower abundance of Actinomyces (FC=0·95, P=0·002), Odoribacter (FC=0·95, P=0·03) and Oscillospira (FC=0·96, P=0·06). A species-level meta-analysis showed that higher fibre intake was marginally associated with greater abundance of Faecalibacterium prausnitzii (FC=1·03, P=0·07) and lower abundance of Eubacterium dolichum (FC=0·96, P=0·04) and Bacteroides uniformis (FC=0·97, P=0·05). Thus, dietary fibre intake may impact gut microbiota composition, particularly class Clostridia, and may favour putatively beneficial bacteria such as F. prausnitzii. These findings warrant further understanding of diet-microbiota relationships for future development of colorectal cancer prevention strategies.

Dietary sodium butyrate (Butirex® C4) supplementation modulates intestinal transcriptomic responses and augments disease resistance of rainbow trout (Oncorhynchus mykiss)

Intestine in fish is a complex multifunctional organ, not only plays roles in digestion and absorption of nutrient, but also has critical role in immunity. The present study evaluated the effects of different levels of dietary sodium butyrate [Butirex^® C4 (Butirex)] on intestinal immune-,antioxidant-and tight junction-related gene expression injuvenile rainbow trout(Oncorhynchusmykiss). 240 healthy rainbow trout were dispensed in 12 fiberglass tanks appointed to four treatments [0 (control), 1.5 (B1.5), 2.5 (B2.5) and 5 (B5)g Butirex per kg diet]. After a 45-day feeding trial, the fish fed with the Butirex-supplemented diets showed higher intestinal lysozyme (LYZ), complement(ACH50) and bactericidal activities; the elevations in ACH50 and bactericidal activities depended on Butirex levels (P < 0.05). The Butirex-supplemented groups, particularly the B2.5 group, had significantly higher LYZ gene expression compared to the control group (P < 0.05). Butirex at 2.5 and 5 g/kg levels led to significantly higher IL-1β gene expression. B2.5 and B5 had significantly lower and higher TNF-α gene expression compared to the control group (P < 0.05). The B2.5 group had significantly higher TGF-B, and significantly lower IL-8 compared to the control group (P < 0.05). The B1.5 and B2.5 group had significantly higher IL-10 gene expression compared to the control group (P < 0.05). The B2.5 and B5 groups had significantly higher SOD gene expression compared to the other groups; the highest expression was related to the B2.5 group (P < 0.05). Dietary Butirex supplementation significantly up-regulated CAT and GPx genes expression compared to the control group; the highest expression as related to the B2.5 and B5 groups (P < 0.05). The B2.5 group had significantly lower CLD12 gene expression compared to the control group (P < 0.05). The B2.5 and B5 groups had significantly higher CLD3, OCLD and ZO-1 gene expression compared to the control. The highest CLD3, ZO-1 gene expressions was related to the B2.5, and B5 groups respectively (P < 0.05). After challenge with Streptococcus iniae, B2.5 and B5 had significantly higher survival compared to the control group (55.6 ± 7.70 and 68.9 ± 10.2 vs. 33.3 ± 6.67). In conclusion, Butirex is efficient immune stimulant and health booster in rainbow trout, which augments the fish resistance to disease. Modulation of immune components, cytokines, antioxidant system and intestinal integrity might involve in improving disease resistance in Butirex-treated fish. Although most of the examined genes were modulated by 2.5 g/kg Butirex under normal conditions, 5 g/kg level is recommended under pathogenic state to mitigate mortality.