Effects of different diets on intestinal microbiota and nonalcoholic fatty liver disease development

A novel peptide from yak ameliorates hypoxia-induced cardiac dysfunction via targeting gut microbiota and HIF-1α pathway

Due to the high altitude and low oxygen levels, individuals residing or traveling in high-altitude regions often experience hypoxic cardiac dysfunction, which significantly affects their overall well-being and quality of life. Our previous investigations showed that peptide from yak milk residue exhibits notable antioxidant, anti-inflammatory, and anti-apoptotic properties that may have a good regulatory effect on hypoxic cardiac dysfunction. In this study, our results suggest that oral administration of yak milk peptide T3 improves the cardiac dysfunction of mice by the hypoxia-inducible factor 1α (HIF-1α) pathway, and these results may be related to the regulation of T3 on the gut microbiota of mice. Additionally, oral administration T3 enhances the permeability of the intestinal barrier and reduces intestinal inflammation. Further analysis revealed that the genera Oscillospira, Clostridium, and Staphylococcus are associated with aspartate aminotransferase, lactate dehydrogenase, and reactive oxygen species levels in heart tissues, which could ameliorate hypoxia-induced myocardial injury in mice. In vitro cell models have also confirmed that T3 intervention can activate the HIF-1α pathway and inhibit myocardial inflammation and cardiomyocyte apoptosis. These findings suggest that T3 may be a potential candidate for developing functional foods to reduce hypoxia-induced cardiac dysfunction.

Structural characteristics and nonvolatile metabolites of theabrownins and their impact on intestinal microbiota in high-fat-diet-fed mice

This study prepared enzymatic theabrownins (TBs-e), alkaline theabrownins (TBs-a), and Pu-erh tea theabrownins (TBs-f), and investigated whether different preparation processes affected the structures, nonvolatile metabolites, and biofunctional activities of TBs. Structural characterization revealed that TBs were polymeric phenolic compounds rich in hydroxyl and carboxyl groups. Nontargeted metabolomics revealed that amino acids were the primary nonvolatile metabolites in TBs-e and TBs-a, accounting for over 70 % of the total nonvolatile content. TBs-f contained more polyphenols, caffeine, and flavonoids, accounting for 14.2 %, 3.9 %, and 0.8 % of total nonvolatile content, respectively. In vivo, at 560 mg/kg body weight, TBs-f were associated with regulation of blood glucose and lipid concentrations in mice. Moreover, 16S rRNA indicated that at 1120 mg/kg body weight, TBs-a were associated with increased numbers of microbiota linked with hypolipidemic activity. This study explores the impacts of different preparation processes on TBs and provides a theoretical foundation for the understanding of TBs.

Immune Remodeling during Aging and the Clinical Significance of Immunonutrition in Healthy Aging

Aging is associated with changes in the immune system and the gut microbiota. Immunosenescence may lead to a low-grade, sterile chronic inflammation in a multifactorial and dynamic way, which plays a critical role in most age-related diseases. Age-related changes in the gut microbiota also shape the immune and inflammatory responses. Nutrition is a determinant of immune function and of the gut microbiota. Immunonutrion has been regarded as a new strategy for disease prevention and management, including many age-related diseases. However, the understanding of the cause-effect relationship is required to be more certain about the role of immunonutrition in supporting the immune homeostasis and its clinical relevance in elderly individuals. Herein, we review the remarkable quantitative and qualitative changes during aging that contribute to immunosenescence, inflammaging and microbial dysbiosis, and the effects on late-life health conditions. Furthermore, we discuss the clinical significance of immunonutrition in the treatment of age-related diseases by systematically reviewing its modulation of the immune system and the gut microbiota to clarify the effect of immunonutrition-based interventions on the healthy aging.

Spirulina (Arthrospira platensis) Improved Nonalcoholic Fatty Liver Disease Characteristics and Microbiota and Did Not Affect Organ Fibrosis Induced by a Fructose-Enriched Diet in Wistar Male Rats

Spirulina (Arthrospira platensis) is reported to play a role in improving nonalcoholic fatty liver disease (NAFLD) and intestinal microbiota (IM). To study spirulina's effects in the improvement of NAFLD characteristics, IM, and pancreatic-renal lesions induced by a fructose-enriched diet, 40 Wistar healthy male rats, weighing 200-250 g, were randomly divided into four groups of 10, and each rat per group was assigned a diet of equal quantities (20 g/day) for 18 weeks. The first control group (CT) was fed a standardized diet, the second group received a 40% fructose-enriched diet (HFr), and the third (HFr-S5) and fourth groups (HFr-S10) were assigned the same diet composition as the second group but enriched with 5% and 10% spirulina, respectively. At week 18, the HFr-S10 group maintained its level of serum triglycerides and had the lowest liver fat between the groups. At the phylae and family level, and for the same period, the HFr-S10 group had the lowest increase in the Firmicutes/Bacteroidetes ratio and the Ruminococcaceae and the highest fecal alpha diversity compared to all other groups (p < 0.05). These findings suggest that at a 10% concentration, spirulina could be used in nutritional intervention to improve IM, fatty liver, metabolic, and inflammatory parameters associated with NAFLD.

Unlocking the Therapeutic Potential of Ellagic Acid for Non-Alcoholic Fatty Liver Disease and Non-Alcoholic Steatohepatitis

Obesity is in epidemic proportions in many parts of the world, contributing to increasing rates of non-alcoholic fatty liver disease (NAFLD). NAFLD represents a range of conditions from the initial stage of fatty liver to non-alcoholic steatohepatitis (NASH), which can progress to severe fibrosis, through to hepatocellular carcinoma. There currently exists no treatment for the long-term management of NAFLD/NASH, however, dietary interventions have been investigated for the treatment of NASH, including several polyphenolic compounds. Ellagic acid is one such polyphenolic compound. Nutraceutical food abundant in ellagic acid undergoes initial hydrolysis to free ellagic acid within the stomach and small intestine. The proposed mechanism of action of ellagic acid extends beyond its initial therapeutic potential, as it is further broken down by the gut microbiome into urolithin. Both ellagic acid and urolithin have been found to alleviate oxidative stress, inflammation, and fibrosis, which are associated with NAFLD/NASH. While progress has been made in understanding the pharmacological and biological activity of ellagic acid and its involvement in NAFLD/NASH, it has yet to be fully elucidated. Thus, the aim of this review is to summarise the currently available literature elucidating the therapeutic potential of ellagic acid and its microbial-derived metabolite urolithin in NAFLD/NASH.

Impacts of gut microbiota alteration on age-related chronic liver diseases

The gut microbiome and its metabolites are involved in developing and progressing liver disease. Various liver illnesses, such as non-alcoholic fatty liver disease, alcoholic liver disease, hepatitis C, and hepatocellular carcinoma, are made worse and have worse prognoses with aging. Dysbiosis, which occurs when the symbiosis between the microbiota and the host is disrupted, can significantly negatively impact health. Liver disease is linked to qualitative changes, such as an increase in hazardous bacteria and a decrease in good bacteria, as well as quantitative changes in the overall amount of bacteria (overgrowth). Intestinal gut microbiota and their metabolites may lead to chronic liver disease development through various mechanisms, such as increasing gut permeability, persistent systemic inflammation, production of SCFA, bile acids, and alteration in metabolism. Age-related gut dysbiosis can disrupt the communication between gut microbiota and the host, impacting the host's health and lifespan. With aging, a gradual loss of the ability to maintain homeostasis because of structural alteration and gut dysbiosis leads to the disease progression in end-stage liver disease. Recently chronic liver disease has been identified as a global problem. A large number of patients are receiving liver transplants yearly. Thereby gut microbiome ecology is changing in the patients of the gut due to the changes in pathophysiology during the preoperative stage. The present review summarises the age-associated dysbiosis of gut microbial composition and its contribution to chronic liver disease. This review also provides information about the impact of liver transplant on the gut microbiome and possible disadvantageous effects of alteration in gut microbiota.

Effects of high oleic acid peanuts on mice's liver and adipose tissue metabolic parameters and gut microbiota composition

This study aimed to investigate the effects of two types of peanuts, regular Hanoch (HN) and a new high-oleic cultivar., Hanoch-Oleic (HO), on metabolic parameters and gut microbiota composition. Male C57BL/6 mice were fed with a normal diet (ND) or ND supplemented with HN (NDh) or HO (NDo). Following 18 weeks of diet regimen, the NDo group exhibited reduced body weight and peri-gonadal adipose-to-body weight ratio, paralleled to lesser food consumption. Although blood levels of total cholesterol, HDL-cholesterol, free fatty acids, and liver enzyme levels did not differ between groups, decreased insulin sensitivity was found in the NDh group. Within adipose tissue, the expression of lipolytic and lipogenic enzymes was higher, while those related to lipid oxidation were lower in the NDh group compared to the NDo group. Additionally, HO peanuts consumption promoted the establishment of a healthy microbiota, with an enhanced abundance of Bifidobacterium, Lactobacillus, and Coprococcus genera. In conclusion, the inclusion of the HO peanut cultivar., rather than the conventional peanut cultivar., in a balanced diet was related to better metabolic outcomes and was linked to a favorable microbiota profile.

Gut microbiome and metabolic-associated fatty liver disease: Current status and potential applications

Metabolic-associated fatty liver disease (MAFLD) is one of the most common chronic liver diseases worldwide. In recent years, the occurrence rate of MAFLD has been on the rise, mainly due to lifestyle changes, high-calorie diets, and imbalanced dietary structures, thereby posing a threat to human health and creating heavy social and economic burdens. With the development of 16S sequencing and integrated multi-omics analysis, the role of the gut microbiota (GM) and its metabolites in MAFLD has been further recognized. The GM plays a role in digestion, energy metabolism, vitamin synthesis, the prevention of pathogenic bacteria colonisation, and immunoregulation. The gut-liver axis is one of the vital links between the GM and the liver. Toxic substances in the intestine can enter the liver through the portal vascular system when the intestinal barrier is severely damaged. The liver also influences the GM in various ways, such as bile acid circulation. The gut-liver axis is essential in maintaining the body's normal physiological state and plays a role in the onset and prognosis of many diseases, including MAFLD. This article reviews the status of the GM and MAFLD and summarizes the GM characteristics in MAFLD. The relationship between the GM and MAFLD is discussed in terms of bile acid circulation, energy metabolism, micronutrients, and signalling pathways. Current MAFLD treatments targeting the GM are also listed.

The microbiota and metabolites during the fermentation of intact plant cells depend on the content of starch, proteins and lipids in the cells

Intact cells, as the smallest unit of whole foods, were isolated from three legume crops and fermented with human faecal inoculum to elucidate the effect of food macro-nutrients compositional difference (starch, proteins and lipids) on in vitro colonic fermentation profiles. After 48 h of fermentation, the highest production of short-chain fatty acids (SCFAs) were observed for the pea cells, abundance in starch (64.9 %, db). In contrast, branch chain fatty acids (BCFAs) were the major metabolites for protein-enriched soybean cells (protein content 56.9 %, db). The peanut cells rich in lipids (49.2 %, db) has the lowest fermentation rate among the three varieties. Correspondingly, pea cells favoured the growth of Bifidobacterium, whereas soybean and peanut cells promoted an abundance of Bacteroides and Shigella, respectively. Furthermore, except the intact pea cells promoting the abundance of butyrate producer Roseburia, a similar fermentation pattern was found between intact and broken cells suggesting that macro-nutrient types, rather than structure, dominate the production of metabolites in colonic fermentation. The findings elucidate how the food compositional difference can modulate the gut microbiome and thus provide the knowledge to design whole food legumes-based functional foods.

Assessing the in vivo ameliorative effects of Lactobacillus acidophilus KLDS1.0901 for induced non-alcoholic fatty liver disease treatment

Reputed as a significant metabolic disorder, non-alcoholic fatty liver disease (NAFLD) is characterized by high-fat deposits in the liver and causes substantial economic challenges to any country's workforce. Previous studies have indicated that some lactic acid bacteria may effectively prevent or treat NAFLD. Overall, L. acidophilus KLDS1.0901 protected against HFD-induced NAFLD by improving liver characteristics and modulating microbiota composition, and thus could be a candidate for improving NAFLD. This study aimed to assess the protective effects of L. acidophilus KLDS1.0901 on a high-fat diet(HFD)-induced NAFLD. First, hepatic lipid profile and histological alterations were determined to study whether L. acidophilus KLDS1.0901 could ameliorate NAFLD. Then, the intestinal permeability and gut barrier were explored. Finally, gut microbiota was analyzed to elucidate the mechanism from the insights of the gut-liver axis. The results showed that Lactobacillus KLDS1.0901 administration significantly decreased body weight, Lee's index body, fat rate, and liver index. L. acidophilus KLDS1.0901 administration significantly improved lipid profiles by decreasing the hepatic levels of total cholesterol (TC), triglyceride (TG), and low-density lipoprotein cholesterol (LDL-C) and by increasing the high-density lipoprotein cholesterol (HDL-C) levels. A conspicuous decrease of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in serum was observed after L. acidophilus KLDS1.0901 administration. Meanwhile, the H&E and Oil Red O-stained staining showed that L. acidophilus KLDS1.0901 significantly reduced liver lipid accumulation of HFD-fed mice by decreasing the NAS score and lipid area per total area. Our results showed that L. acidophilus KLDS1.0901 administration decreased the interleukin-6 (IL-6), interleukin-1β (IL-1β), and tumor necrosis factor-alpha (TNF-α) concentrations accompanied by the increase of interleukin-10 (IL-10). L. acidophilus KLDS1.0901 administration could improve the intestinal barrier function by upregulating the mRNA levels of occludin, claudin-1, ZO-1, and Muc-2, which were coupled to the decreases of the concentration of LPS and D-lactic acid. Notably, L. acidophilus KLDS1.0901 administration modulated the gut microbiota to a near-normal pattern. Hence, our results suggested that L. acidophilus KLDS1.0901 can be used as a candidate to ameliorate NAFLD.

Gypenosides counteract hepatic steatosis and intestinal barrier injury in rats with metabolic associated fatty liver disease by modulating the adenosine monophosphate activated protein kinase and Toll-like receptor 4/nuclear factor kappa B pathways

CONTEXT

Non-alcoholic fatty liver disease (NAFLD), the most common chronic liver disease, can develop into metabolic associated fatty liver disease (MAFLD). Gypenosides (GP), the main phytochemical component of Gynostemma pentaphylla (Thunb.) Makino (Cucurbitaceae), have been applied for treatment of metabolic diseases.

OBJECTIVE

We investigate how GP modulate MAFLD-related hepatic steatosis and intestinal barrier injury.

MATERIALS AND METHODS

In cell experiments, Caco-2 cells were treated with GP (150 or 200 μmol/L, 24 h), following lipopolysaccharide (LPS) exposure (10 μg/mL, 24 h) to mimic MAFLD in vitro. In in vivo experiments, control, model and model + GP groups were set. High fructose diet/high fat (HFD/HF)-fed (12 weeks) MAFLD rats received GP treatment (300 mg/kg, 6 weeks), followed by intra-peritoneal glucose tolerance test and histopathological examination of rat liver and intestinal mucosa using haematoxylin-eosin staining.

RESULTS

GP at 200 μM significantly reversed LPS-induced decreases in transepithelial electrical resistance (TER) value (25%), protein expression of occludin (two fold) and ZO-1 (four fold), and the ratio of p-AMPK to AMPK (five fold), while partially repressing LPS-induced leakage of FD4 (50%) and LPS-induced increases in the Toll-like receptor 4 (TLR4) level (50%) and the ratio of p-p65 to p65 (55%). Compared with the model rats, rats with GP treatment presented a reduction in gain of weight and glucose tolerance. In addition, GP alleviated HFD/HF-induced histopathological abnormalities in rat liver and intestinal mucosa.

CONCLUSIONS

GP attenuates hepatic steatosis and intestinal barrier injury in MAFLD rats via the AMPK and TLR4/nuclear factor kappa B (NF-κB) pathways, providing a potential treatment for MAFLD patients.

Sesamolin Alleviates Nonalcoholic Fatty Liver Disease through Modulating Gut Microbiota and Metabolites in High-Fat and High-Fructose Diet-Fed Mice

Nonalcoholic fatty liver disease (NAFLD) has become a major public health problem. The effects of sesamolin on obesity-associated NAFLD and its possible mechanism are still poorly understood. The present study investigated the effects of sesamolin on NAFLD and changes in gut microbiota and serum metabolites in high-fat and high-fructose (HF-HF) diet-fed mice. Mice with NAFLD were treated with or without sesamolin. Sesamolin effectively suppressed obesity-associated metabolic disorder, attenuated hepatic steatosis and the infiltration of inflammatory cells, and decreased levels of hepatic proinflammatory cytokines. Sesamolin also altered the composition of gut microbiota at the genus level. Additionally, differential serum metabolite biomarkers identified in an untargeted metabolomics analysis showed that sesamolin changed the levels of metabolites and influenced metabolomics pathways including caffeine metabolism, steroid hormone biosynthesis, and cysteine and methionine metabolism. Changes in metabolite biomarkers and the abundances of Faecalibaculum, Lachnoclostridium, Mucispirillum, Allobaculum, and Bacteroides are highly correlated with those factors involved in the progression of NAFLD. These results are important in deciphering new mechanisms by which changes in bacteria and metabolites in sesamolin treatment might be associated with the alleviation of obesity-associated NAFLD in HF-HF diet-fed mice. Thus, sesamolin may be a potential compound for obesity-associated NAFLD treatment.

Effects of Stocking Density on Fatty Acid Metabolism by Skeletal Muscle in Mice

Specific pathogen-free (SPF) grade laboratory animals are kept in specific cages for life. The limited space could affect the characterization of colonization and dynamic changes related to gut microorganisms, and affect adipokines, even further affecting the fat synthesis and muscle quality of animals. The objective of this study was to analyze the stocking density on the dynamic distribution of gut microbiota, fat synthesis and muscle quality of SPF grade Kunming mice. Three housing densities were accomplished by raising different mice per cage with the same floor size. Kunming mice were reared at low stocking density (LSD, three mice a group), medium stocking density (MSD, 5 mice a group), and high stocking density (HSD, 10 mice a group) for 12 weeks. The results demonstrated that the stocking density affected intestinal microbial flora composition. We found that compared with the MSD group, the abundance of Lactobacillus in the LSD group and the HSD group decreased, but the abundance of unclassified_Porphyromonadaceae increased. Moreover, fat synthesis and muscle quality were linked to the intestinal microbial flora and stocking density. Compared with the LSD group and the HSD group, the MSD group had a more balanced gut flora, higher fat synthesis and higher muscle quality. Overall, this study demonstrated that stocking density could affect gut microbiota composition, and reasonable stocking density could improve fat synthesis and muscle quality. Our study will provide theoretical support for the suitable stocking density of laboratory animals.

Synbiotic Supplementation Modulates Gut Microbiota, Regulates β-Catenin Expression and Prevents Weight Gain in ob/ob Mice: Preliminary Findings

BACKGROUND

Obesity is one of the main health problems in the world today, and dysbiosis seems to be one of the factors involved. The aim of this study was to examine the impact of synbiotic supplementation on obesity and the microbiota in ob/ob mice. Twenty animals were divided into four groups: obese treated (OT), obese control (OC), lean treated (LT) and lean control (LC). All animals received a standard diet for 8 weeks. The treated groups received a synbiotic (Simbioflora-Invictus Farmanutrição Ltd., Sao Paulo, Brazil) in water, while the nontreated groups received only water. After 8 weeks, all animals were sacrificed, and gut tissue and stool samples were collected for mRNA isolation and microbiota analysis, respectively. β-Catenin, occludin, cadherin and zonulin in the gut tissue were analyzed via RT-qPCR. Microbiome DNA was extracted from stool samples and sequenced using an Ion PGM Torrent platform.

RESULTS

Synbiotic supplementation reduced body weight gain in the OT group compared with the OC group (p = 0.0398) and was associated with an increase in Enterobacteriaceae (p = 0.005) and a decrease in Cyanobacteria (p = 0.047), Clostridiaceae (p = 0.026), Turicibacterales (p = 0.005) and Coprococcus (p = 0.047). On the other hand, a significant reduction in Sutterella (p = 0.009) and Turicibacter (p = 0.005) bacteria was observed in the LT group compared to the LC group. Alpha and beta diversities were different among all treated groups. β-Catenin gene expression was significantly decreased in the gut tissue of the OT group (p ≤ 0.0001) compared to the other groups. No changes were observed in occludin, cadherin or zonulin gene expression in the gut tissue.

CONCLUSIONS

Synbiotic supplementation prevents excessive weight gain, modulates the gut microbiota, and reduces β-catenin expression in ob/ob mice.

Inhibitory Effects of Mongolian Medicine Yihe-Tang on Continuous Darkness Induced Liver Steatosis in Zebrafish

The constant dark induction (DD) causes lipid degeneration and nonalcoholic fatty liver disease (NAFLD) in zebrafish, which might be closely related to the imbalance of gut microbiota and require in-depth study. In this study, a total of 144 zebrafish were divided into four groups, including the control group, Yihe-Tang group, constant dark group, and constant dark + Yihe-Tang group, and were treated with constant darkness (except control and Yihe-Tang groups) for 21 days. The bodyweights of zebrafish were recorded after 8 d, 15 d, and 22 d. The sequencing analysis of gut microbiota, detection of liver histopathological changes, and comparison of lipid metabolism-related gene expression levels were performed on the 22^nd day of the experiment. The results showed that the Yihe-Tang could inhibit the constant dark-induced increase in zebrafish weight and liver steatosis. As compared to the control group, the dark treatment could alter the composition of gut microbiota in zebrafish, increase the relative abundance of harmful bacteria, and decrease the Cetobacterium and Bacteroides to Firmicutes ratio in the intestines. The abundance of Proteobacteria in the constant dark + Yihe-Tang group was close to that in the control group and that of Fusobacteria and Cetobacterium increased, especially the Cetobacterium, which increased significantly. The constant dark treatment caused an abnormal expression of liver lipid-related genes, inhibited lipid metabolism, and promoted fat accumulation. However, the Yihe-Tang could restore these changes to the level of the control group. This study indicated that Yihe-Tang could restore the constant dark-induced liver lipid degeneration. We hypothesized that Cetobacterium could significantly inhibit steatosis.

Obesity influences composition of salivary and fecal microbiota and impacts the interactions between bacterial taxa

Obesity is an increasing global health concern and is associated with a broad range of morbidities. The gut microbiota are increasingly recognized as important contributors to obesity and cardiometabolic health. This study aimed to characterize oral and gut microbial communities, and evaluate host: microbiota interactions between clinical obesity classifications. We performed 16S rRNA sequencing on fecal and salivary samples, global metabolomics profiling on plasma and stool samples, and dietary profiling in 135 healthy individuals. We grouped individuals by obesity status, based on body mass index (BMI), including lean (BMI 18-124.9), overweight (BMI 25-29.9), or obese (BMI ≥30). We analyzed differences in microbiome composition, community inter-relationships, and predicted microbial function by obesity status. We found that salivary bacterial communities of lean and obese individuals were compositionally and phylogenetically distinct. An increase in obesity status was positively associated with strong correlations between bacterial taxa, particularly with bacterial groups implicated in metabolic disorders including Fretibacterium, and Tannerella. Consumption of sweeteners, especially xylitol, significantly influenced compositional and phylogenetic diversities of salivary and fecal bacterial communities. In addition, obesity groups exhibited differences in predicted bacterial metabolic activity, which was correlated with host's metabolite concentrations. Overall, obesity was associated with distinct changes in bacterial community dynamics, particularly in saliva. Consideration of microbiome community structure and inclusion of salivary samples may improve our ability to understand pathways linking microbiota to obesity and cardiometabolic disease.

The Antioxidant Properties of Alfalfa (Medicago sativa L.) and Its Biochemical, Antioxidant, Anti-Inflammatory, and Pathological Effects on Nicotine-Induced Oxidative Stress in the Rat Liver

Medicago sativa Linn or alfalfa is a tonic plant rich in proteins, vitamins, and minerals that is used to treat many diseases due to its pharmacological properties such as anti-inflammatory and antioxidant activities. So, the aim of this study was to evaluate the efficacy of alfalfa methanolic extract (AME) on the prevention of liver damage caused by nicotine. The total phenols, flavonoids levels, and the free radical scavenging activity of its extract (IC50) were measured. In this study, 30 Wistar rats were randomly divided into 5 groups as control (untreated), N (nicotine only), T1, T2, and T3 (nicotine + AME 100, 250, and 500 mg/kg/day, respectively). AME (orally) and nicotine (intraperitoneal injection, 0.5 mg/kg/day) were then administered for 21 days. Weight gain, the liver-to-body weight ratio, liver functional enzymes, and the lipid profile were measured. Moreover, we evaluated oxidative stress, proinflammatory parameters, and histopathological changes in the liver. Total phenols, flavonoids, and IC50 were determined as $51.68\pm 0.62$  mg GAE/g, $18.55\pm 1.01$  mg QE/g, and $350.91\pm 16.46$  μg/ml, respectively. Nicotine changed the measured parameters to abnormal. AME increased weight gain, the liver-to-body weight ratio, and enzymatic antioxidant levels and decreased malondialdehyde, liver functional enzymes, and proinflammatory cytokine levels. The lipid profile and histopathological changes have also been improved by AME in a dose-dependent manner. The results showed that AME in a dose-dependent manner by improving the inflammation and oxidative damage could improve the liver damage caused by nicotine.

Broccoli Florets Supplementation Improves Insulin Sensitivity and Alters Gut Microbiome Population-A Steatosis Mice Model Induced by High-Fat Diet

Nonalcoholic fatty liver disease (NAFLD) is linked to obesity, type 2 diabetes, hyperlipidemia, and gut dysbiosis. Gut microbiota profoundly affects the host energy homeostasis, which, in turn, is affected by a high-fat diet (HFD) through the liver-gut axis, among others. Broccoli contains beneficial bioactive compounds and may protect against several diseases. This study aimed to determine the effects of broccoli supplementation to an HFD on metabolic parameters and gut microbiome in mice. Male (7–8 weeks old) C57BL/J6 mice were divided into four groups: normal diet (ND), high-fat diet (HFD), high-fat diet+10% broccoli florets (HFD + F), and high-fat diet + 10% broccoli stalks (HFD + S). Liver histology and serum biochemical factors were evaluated. Alterations in protein and gene expression of the key players in lipid and carbohydrate metabolism as well as in gut microbiota alterations were also investigated. Broccoli florets addition to the HFD significantly reduced serum insulin levels, HOMA-IR index, and upregulated adiponectin receptor expression. Conversely, no significant difference was found in the group supplemented with broccoli stalks. Both broccoli stalks and florets did not affect fat accumulation, carbohydrate, or lipid metabolism-related parameters. Modifications in diversity and in microbial structure of proteobacteria strains, Akermansia muciniphila and Mucispirillum schaedleri were observed in the broccoli-supplemented HFD-fed mice. The present study suggests that dietary broccoli alters parameters related to insulin sensitivity and modulates the intestinal environment. More studies are needed to confirm the results of this study and to investigate the mechanisms underlying these beneficial effects.

Personalized bioconversion of Panax notoginseng saponins mediated by gut microbiota between two different diet-pattern healthy subjects

Background

Panax notoginseng saponins (PNS) as the main effective substances from P. notoginseng with low bioavailability could be bio-converted by human gut microbiota. In our previous study, PNS metabolic variations mediated by gut microbiota have been observed between high fat, high protein (HF-HP) and low fat, plant fiber-rich (LF-PF) dietary subjects. In this study, we aimed to correspondingly characterize the relationship between distinct gut microbial species and PNS metabolites.

Methods

Gut microbiota were collected from HF-HP and LF-PF dietary healthy adults and profiled by 16S rRNA gene sequencing. PNS were incubated with gut microbiota in vitro. A LC–MS/MS method was developed to quantify the five main metabolites yields including ginsenoside F₁ (GF₁), ginsenoside Rh₂ (GRh₂), ginsenoside compound K (GC-K), protopanaxatriol (PPT) and protopanaxadiol (PPD). The selected microbial species, Bifidobacterium adolescentis and Lactobacillus rhamnosus, were employed to metabolize PNS for the corresponding metabolites.

Results

The five main metabolites were significantly different between the two diet groups. Compared with HF-HP group, the microbial genus Blautia, Bifidobacterium, Clostridium, Corynebacterium, Dorea, Enhydrobacter, Lactobacillus, Roseburia, Ruminococcus, SMB53, Streptococcus, Treponema and Weissella were enriched in LF-PF group, while Phascolarctobacterium and Oscillospira were relatively decreased. Furthermore, Spearman’s correlative analysis revealed gut microbials enriched in LF-PF and HF-HP groups were positively and negatively associated with the five metabolites, respectively.

Conclusions

Our data showed gut microbiota diversity led to the personalized bioconversion of PNS.

Graphic Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s13020-021-00476-5.

Panax notoginseng saponins could be biotransformed to generate five main metabolites, including GF₁, GRh₂, GC-K, PPT and PPD, by human gut microbiota.

Gut microbiota profiles were significantly different in high protein, high fat and low fat, plant fiber-rich diet-pattern groups.

Correlation analysis revealed potential relationships between metabolites and gut microbial species.

Bifidobacterium adolescentis and Lactobacillus rhamnosus were selected as a representative species to metabolize PNS for the concerned metabolites.

An alcohol-free beer enriched with isomaltulose and a resistant dextrin modulates gut microbiome in subjects with type 2 diabetes mellitus and overweight or obesity: a pilot study

We aimed to study the effect of consuming an alcohol-free beer with modified carbohydrates composition (almost completely eliminating maltose and adding isomaltulose (16.5 g day^-1) and resistant maltodextrin (5.28 g day^-1)) in gut microbiome, compared to regular alcohol-free beer in subjects with T2DM or prediabetes and overweight/obesity. This is a pilot, randomized, double-blinded, crossover study including a sub-sample of a global study with 14 subjects: (a) consuming 66 cl day^-1 of regular alcohol-free beer for the first 10 weeks and 66 cl day^-1 of modified alcohol-free beer for the next 10 weeks; (b) the same described intervention in opposite order. BMI homogeneously decreased after both interventions. Glucose and HOMA-IR significantly decreased just after the participants consumed modified alcohol-free beer. These findings were in the same line as those reported in the global study. Dominant bacteria at baseline were Bacteroidetes, Firmicutes, Proteobacteria and Tenericutes. Parabacteroides, from the Porphymonadaceae family, resulted as the feature with the greatest difference between beers (ANCOM analysis, W = 15). Feature-volatility analysis confirmed the importance of Parabacteroides within the model. Alcohol-free beers consumption resulted in an enhancement of pathways related to metabolism according to PICRUSt analysis, including terpenoid-quinone, lipopolysaccharides and N-glycan biosynthesis. Thus, an alcohol-free beer including the substitution of regular carbohydrates for low doses of isomaltulose and the addition of maltodextrin within meals significantly impacts gut microbiota in diabetic subjects with overweight or obesity. This could, at least partially, explain the improvement in insulin resistance previously found after taking modified alcohol-free alcohol.Clinical Trial Registration: Registered under ClinicalTrials.gov identifier no. NCT03337828.

Nutritional Approach Targeting Gut Microbiota in NAFLD-To Date

Non-alcoholic fatty liver disease (NAFLD) is a significant clinical and epidemiological problem that affects around 25% of the adult global population. A large body of clinical evidence highlights that NAFLD is associated with increased liver-related morbidity and mortality and an increased risk of cardiovascular disease, extrahepatic cancers, type 2 diabetes, and chronic kidney disease. Recently, a series of studies revealed the pivotal role of gut microbiota (GM) dysbiosis in NAFLD's pathogenesis. The GM plays an essential role in different metabolic pathways, including the fermentation of diet polysaccharides, energy harvest, choline regulation, and bile acid metabolism. One of the most critical factors in GM stabilization is the diet; therefore, nutritional therapyappearsto be a promising tool in NAFLD therapy. This paper aims to review the current knowledge regardingthe nutritional approach and its implications with GM and NAFLD treatment. We discuss the positive impact of probiotics, prebiotics, and symbiotics in a reverse dysbiosis state in NAFLD and show the potential beneficial effects of bioactive substances from the diet. The full description of the mechanism of action and comprehensive examination of the impact of nutritional interventions on GM modulation may, in the future, be a simple but essential tool supporting NAFLD therapy.

Gut Dysbiosis and Increased Intestinal Permeability Drive microRNAs, NLRP-3 Inflammasome and Liver Fibrosis in a Nutritional Model of Non-Alcoholic Steatohepatitis in Adult Male Sprague Dawley Rats

BACKGROUND/AIM

The interactions between the gut and liver have been described in the progression of non-alcoholic steatohepatitis (NASH). The aim of this study was to develop an experimental nutritional model of NASH simulating metabolic changes occurring in humans.

MATERIALS AND METHODS

Adult male Sprague Dawley rats were randomized into two groups: controls (standard diet) and intervention (high-fat and choline-deficient diet) for 16 weeks, each experimental group with 10 animals. Biochemical analysis, hepatic lipid content, microRNAs, inflammatory, gut permeability markers and gut microbiota were measured.

RESULTS

Animals in the intervention group showed significantly higher delta Lee index (p=0.017), abdominal circumference (p<0.001), abdominal adipose tissue (p<0.001) and fresh liver weight (p<0.001), as well as higher serum levels of alanine aminotransferase (p=0.010), glucose (p=0.013), total cholesterol (p=0.033), LDL cholesterol (p=0.011), and triglycerides (p=0.011), and lower HDL cholesterol (p=0.006) compared to the control group. Higher TLR4 (p=0.041), TLR9 (p=0.033), MyD88 (p=0.001), Casp1 (p<0.001), NLPR3 (p=0.019), liver inflammation index interleukin (IL)-1β/IL10 (p<0.001), IL6/IL10 (p=0.002) and TNFα/IL10 (p=0.001) were observed in the intervention group, and also lower permeability markers Ocln (p=0.003) and F11r (p=0.041). Gene expression of miR-122 increased (p=0.041) and miR-145 (p=0.010) decreased in the intervention group. Liver steatosis, inflammation and fibrosis, along with collagen fiber deposition increment (p<0.001), were seen in the intervention group. Regarding gut microbiota, Bray-Curtis dissimilarity index and number of operational taxonomic units were significantly different (p<0.001) between the groups. Composition of the gut microbiota showed a significant correlation with histopathological score of NAFLD (r=0.694) and index IL-1β/IL-10 (r=0.522).

CONCLUSION

This experimental model mimicking human NASH demonstrated gut and liver interaction, with gut microbiota and intestinal permeability changes occurring in parallel with systemic and liver inflammation, miRNAs regulation and liver tissue damage.

Effects of a Vegetarian Diet on Cardiometabolic Risk Factors, Gut Microbiota, and Plasma Metabolome in Subjects With Ischemic Heart Disease: A Randomized, Crossover Study

Background A vegetarian diet (VD) may reduce future cardiovascular risk in patients with ischemic heart disease. Methods and Results A randomized crossover study was conducted in subjects with ischemic heart disease, assigned to 4-week intervention periods of isocaloric VD and meat diet (MD) with individually designed diet plans, separated by a 4-week washout period. The primary outcome was difference in oxidized low-density lipoprotein cholesterol (LDL-C) between diets. Secondary outcomes were differences in cardiometabolic risk factors, quality of life, gut microbiota, fecal short-chain and branched-chain fatty acids, and plasma metabolome. Of 150 eligible patients, 31 (21%) agreed to participate, and 27 (87%) participants completed the study. Mean oxidized LDL-C (-2.73 U/L), total cholesterol (-5.03 mg/dL), LDL-C (-3.87 mg/dL), and body weight (-0.67 kg) were significantly lower with the VD than with the MD. Differences between VD and MD were observed in the relative abundance of several microbe genera within the families Ruminococcaceae, Lachnospiraceae, and Akkermansiaceae. Plasma metabolites, including l-carnitine, acylcarnitine metabolites, and phospholipids, differed in subjects consuming VD and MD. The effect on oxidized LDL-C in response to the VD was associated with a baseline gut microbiota composition dominated by several genera of Ruminococcaceae. Conclusions The VD in conjunction with optimal medical therapy reduced levels of oxidized LDL-C, improved cardiometabolic risk factors, and altered the relative abundance of gut microbes and plasma metabolites in patients with ischemic heart disease. Our results suggest that composition of the gut microbiota at baseline may be related to the reduction of oxidized LDL-C observed with the VD. Registration URL: https://www.clini​caltr​ials.gov; Unique identifier: NCT02942628.

Role of diet on intestinal metabolites and appetite control factors in SD rats

The present study aimed to investigate changes in the levels of metabolites and appetite control factors caused by different dietary interventions in Sprague Dawley (SD) rats. A total of 35 male SD rats were weaned and immediately randomly assigned to five groups. The control group was given ad libitum access to a normal chow diet, and the other groups received a high-fat diet (FAT group), high-sugar diet, high-fibre or high-protein diet (PRO group) for 4 weeks. The high-fat diet contributed to weight gain and adipose tissue formation, and affected lipid indexed. The FAT group had a higher body weight, Lee's index, adipose mass and glucose tolerance than all of the other groups. The opposite effect was observed in the PRO group. High-performance liquid chromatography revealed that short-chain fatty acid and amino acid formation were affected by the various diets. In addition, differences in the mRNA expression levels of leptin, ghrelin and associated receptors were determined in the gastrointestinal, adipose and hypothalamus tissues. The present study provides further evidence of the role of diet in obesity development and prevention. It also highlights the role of intestinal metabolites and appetite control factor expression in the pathogenesis of obesity in SD rats.

Trans-fatty acids alter the gut microbiota in high-fat-diet-induced obese rats

The gut microbiota is directly influenced by dietary components, and it plays critical roles in chronic diseases. Excessive consumption of trans-fatty acids (TFA) is associated with obesity induced by alterations in gut microbiota, but the links between obesity and gut microbiota remain unclear. Therefore, studies examining the impact of TFA on intestinal microflora are essential. In our study, we performed 16S ribosomal RNA gene sequencing on faecal samples from Sprague-Dawley rats fed a basal diet (control (CON) group), high-fat (HF) diet (diet-induced obesity (DIO) group) or TFA diets (1 % TFA group and 8 % TFA group) for 8 weeks to investigate the effects of TFA/HF diets on obesity and gut microbiota composition. We found that the TFA/HF diets significantly induced obesity and changes in blood and brain physiological parameters of the rats. The relative abundance of the phyla Firmicutes and Bacteroidetes was inversely altered in the three test groups compared with the CON group. Proteobacteria increased slightly in the DIO, 1 % TFA and 8 % TFA groups. The genus Bacteroides increased in the DIO and 1 % TFA groups, but Muribaculaceae decreased in all experimental groups compared with the CON group. Moreover, significant differences were observed among clusters of orthologous group functional categories of the four dietary groups. Our observations suggested that the TFA/HF diets induced obesity and dysfunction of gut microbiota. Gut dysbiosis might mediate the obesity effects of TFA/HF diets.

An altered fecal microbiota profile in patients with non-alcoholic fatty liver disease (NAFLD) associated with obesity

INTRODUCTION

increasing evidence suggests a role of intestinal dysbiosis in obesity and non-alcoholic fatty liver disease (NAFLD). The advances in recent years with regard to the role of the gut microbiota raise the potential utility of new therapeutic approaches based on the modification of the microbiome.

OBJECTIVE

the aim of this study was to compare the bacterial communities in obese patients with or without NAFLD to those of healthy controls.

PATIENTS AND METHODS

the fecal microbiota composition of 20 healthy adults, 36 obese patients with NAFLD and 17 obese patients without NAFLD was determined by 16S ribosomal RNA sequencing using the Illumina MiSeq system.

RESULTS

the results highlighted significant differences in the phylum Firmicutes between patients with and without NAFLD, which was a determining factor of the disease and supported its possible role as a marker of NAFLD. At the genus level, the relative abundance of Blautia, Alkaliphilus, Flavobacterium and Akkermansia was reduced in obese patients, both with or without NAFLD, compared to healthy controls. Furthermore, the number of sequences from the genus Streptococcus was significantly higher in patients with NAFLD in comparison with individuals without the disease, constituting another possible marker. Comparison of bacterial communities at the genus level by a principal coordinate analysis indicated that the bacterial communities of patients with NAFLD were dispersed and did not form a group.

CONCLUSION

in conclusion, these results indicate the role of intestinal dysbiosis in the development of NAFLD associated with obesity. There was a differential microbiota profile between obese patients, with and without NAFLD. Thus, supporting gut microbiota modulation as a therapeutic alternative for the prevention and treatment of NAFLD.

Astaxanthin n-Octanoic Acid Diester Ameliorates Insulin Resistance and Modulates Gut Microbiota in High-Fat and High-Sucrose Diet-Fed Mice

Astaxanthin n-octanoic acid diester (AOD) is a type of astaxanthin connecting medium-chain fatty acids with a more stable structure. In this study, we examined the role of AOD in ameliorating insulin resistance (IR) induced by a high-fat and high-sucrose diet (HFD) as well as its effect on modulating gut microbiota in mice, with free astaxanthin (AST) as a comparison. Four groups of male C57BL/6J mice (6 weeks old; n = 10 per group) were fed with a normal control diet (NC), HFD orally administered with AOD, AST (50 mg/kg body weight), or vehicle for 8 weeks. AOD improved glucose tolerance, IR, systematic and intestinal inflammation, and intestinal integrity better than AST. Further, both AOD and AST modulated gut microbiota. A significantly higher abundance of Bacteroides and Coprococcus was found in AOD than in AST, and the predicted pathway of carbohydrate metabolism was significantly impacted by AOD. Overall, AOD may play a role in alleviating IR and inflammation with the modulating effect on microbiota in HFD-fed mice. Our findings could facilitate the development of AOD as a bioactive nutraceutical and more stable alternative to AST.

The biotransformation of Bupleuri Radix by human gut microbiota

1. Bupleuri Radix (BR) is a herbal medicine traditionally used orally in oriental countries, which inevitably comes into contact with the intestinal microbiota. However, whether gut microbiota contribute to the biotransformation of BR, and/or the formation of pharmacologically active compounds remains unknown.2. In this study, the main saikosaponins (SAPs) of Bupleurum (including saikosaponin a, b1, b2, c, d, f, h) and BR extract (BRE) were individually incubated with human fecal suspensions (HFS), and metabolic time courses of SAPs and their metabolites by human gut bacteria were systematically characterized.3. Deglycosylation and dehydration were the main metabolic pathways identified for SAPs including newly investigated saikosaponin f (SSf) and saikosaponin h (SSh); dehydration had not been reported previously. A total of 19 dehydrated and deglycosylated metabolites of SAPs were detected and characterized, and 10 of them were newly identified. Moreover, SAPs of BRE were found to be deglycosylated to prosaikogenins. In addition, 13 metabolic pathways related to human gut microbiota were identified for phytochemicals of BRE except for SAPs. Gut microbiota may play a significant role in the biotransformation of BR in humans.

Relationship between Changes in Microbiota and Liver Steatosis Induced by High-Fat Feeding-A Review of Rodent Models

Several studies have observed that gut microbiota can play a critical role in nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH) development. The gut microbiota is influenced by different environmental factors, which include diet. The aim of the present review is to summarize the information provided in the literature concerning the impact of changes in gut microbiota on the effects which dietary fat has on liver steatosis in rodent models. Most studies in which high-fat feeding has induced steatosis have reported reduced microbiota diversity, regardless of the percentage of energy provided by fat. At the phylum level, an increase in Firmicutes and a reduction in Bacteroidetes is commonly found, although widely diverging results have been described at class, order, family, and genus levels, likely due to differences in experimental design. Unfortunately, this fact makes it difficult to reach clear conclusions concerning the specific microbiota patterns associated with this feeding pattern. With regard to the relationship between high-fat feeding-induced changes in liver and microbiota composition, although several mechanisms such as alteration of gut integrity and increased permeability, inflammation, and metabolite production have been proposed, more scientific evidence is needed to address this issue and thus further studies are needed.

Raw Bowl Tea (Tuocha) Polyphenol Prevention of Nonalcoholic Fatty Liver Disease by Regulating Intestinal Function in Mice

A high-fat diet-induced C57BL/6N mouse model of non-alcoholic fatty liver disease (NAFLD) was established. The effect and mechanism of Raw Bowl Tea polyphenols (RBTP) on preventing NAFLD via regulating intestinal function were observed. The serum, liver, epididymis, small intestine tissues, and feces of mice were examined by biochemical and molecular biological methods, and the composition of RBTP was analyzed by HPLC assay. The results showed that RBTP could effectively reduce the body weight, liver weight, and liver index of NAFLD mice. The serum effects of RBTP were: (1) decreases in alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (AKP), total cholesterol (TC), triglyceride (TG), low density lipoprotein cholesterol (LDL-C), D-lactate (D-LA), diamine oxidase (DAO), lipopolysaccharide (LPS), and an increase of high density lipoprotein cholesterol (HDL-C) levels; (2) a decrease of inflammatory cytokines such as interleukin 1 beta (IL-1β), interleukin 4 (IL-4), interleukin 6 (IL-6), interleukin 10 (IL-10), tumor necrosis factor alpha (TNF-α), and interferon gamma (INF-γ); (3) a decrease the reactive oxygen species (ROS) level in liver tissue; and (4) alleviation of pathological injuries of liver, epididymis, and small intestinal tissues caused by NAFLD and protection of body tissues. qPCR and Western blot results showed that RBTP could up-regulate the mRNA and protein expressions of LPL, PPAR-α, CYP7A1, and CPT1, and down-regulate PPAR-γ and C/EBP-α in the liver of NAFLD mice. In addition, RBTP up-regulated the expression of occludin and ZO-1, and down-regulated the expression of CD36 and TNF-α in the small intestines of NAFLD mice. Studies on mice feces showed that RBTP reduced the level of Firmicutes and increased the minimum levels of Bacteroides and Akkermansia, as well as reduced the proportion of Firmicutes/Bacteroides in the feces of NAFLD mice, which play a role in regulating intestinal microecology. Component analysis showed that RBTP contained seven polyphenolic compounds: Gallic acid, (-)-epigallocatechin, catechin, L-epicatechin, (-)-epigallocatechin gallate, (-)-gallocatechin gallate, and (-)-epicatechin gallate (ECG), and high levels of caffeine, (-)-epigallocatechin (EGC), and ECG. RBTP improved the intestinal environment of NAFLD mice with the contained active ingredients, thus playing a role in preventing NAFLD. The effect was positively correlated with the dose of 100 mg/kg, which was even better than that of the clinical drug bezafibrate.

Freeze-dried Si-Ni-San powder can ameliorate high fat diet-induced non-alcoholic fatty liver disease

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is a common chronic liver disease worldwide. However, to date, there is no ideal therapy for this disease.

AIM

To study the effects of Si-Ni-San freeze-dried powder on high fat diet-induced NAFLD in mice.

METHODS

Twenty-four male C57BL/6 mice were randomized into three groups of eight. The control group (CON) was allowed ad libitum access to a normal chow diet. The high fat diet group (FAT) and Si-Ni-San group (SNS) were allowed ad libitum access to a high fat diet. The SNS group was intragastrically administered Si-Ni-San freeze-dried powder (5.0 g/kg) once daily, and the CON and FAT groups were intragastrically administered distilled water. After 12 wk, body weight, liver index, visceral fat index, serum alanine aminotransferase (ALT), portal lipopoly-saccharide (LPS), liver tumor necrosis factor (TNF)-α and liver triglycerides were measured. Intestinal microbiota were analyzed using a 16S r DNA sequencing technique.

RESULTS

Compared with the FAT group, the SNS group exhibited decreased body weight, liver index, visceral fat index, serum ALT, portal LPS, liver TNF-α and liver triglycerides (P < 0.05). Intestinal microbiota analysis showed that the SNS group had different bacterial composition and function compared with the FAT group. In particular, Oscillospira genus was a bacterial biomarker of SNS group samples.

CONCLUSION

The beneficial effects of Si-Ni-San freeze-dried powder on high fat diet-induced NAFLD in mice may be associated with its anti-inflammatory and changing intestinal microbiota effects.

Metagenomic dissection of the canine gut microbiota: insights into taxonomic, metabolic and nutritional features

Domestication of dogs from wolves is the oldest known example of ongoing animal selection, responsible for generating more than 300 dog breeds worldwide. In order to investigate the taxonomic and functional evolution of the canine gut microbiota, a multi-omics approach was applied to six wild wolves and 169 dog faecal samples, the latter encompassing 51 breeds, which fully covers currently known canine genetic biodiversity. Specifically, 16S rRNA gene and bifidobacterial Internally Transcribed Spacer (ITS) profiling were employed to reconstruct and then compare the canine core gut microbiota to those of wolves and humans, revealing that artificial selection and subsequent cohabitation of dogs with their owners influenced the microbial population of canine gut through loss and acquisition of specific bacterial taxa. Moreover, comparative analysis of the intestinal bacterial population of dogs fed on Bones and Raw Food (BARF) or commercial food (CF) diet, coupled with shotgun metagenomics, highlighted that both bacterial composition and metabolic repertoire of the canine gut microbiota have evolved to adapt to high-protein or high-carbohydrates intake. Altogether, these data indicate that artificial selection and domestication not only affected the canine genome, but also shaped extensively the bacterial population harboured by the canine gut.

The Therapeutic Implications of the Gut Microbiome and Probiotics in Patients with NAFLD

Recent breakthrough in our understanding pertaining to the pathogenesis of nonalcoholic fatty liver disease (NAFLD) has pointed to dysregulation or derangement of the gut microbiome, also known as dysbiosis. This has led to growing interest in probiotic supplementation as a potential treatment method for NAFLD due to its ability to retard and/or reverse dysbiosis and restore normal gut flora. A thorough review of medical literature was completed from inception through July 10, 2018 on the PubMed database by searching for key terms such as NAFLD, probiotics, dysbiosis, synbiotics, and nonalcoholic steatohepatitis (NASH). All studies reviewed indicate that probiotics had a beneficial effect in patients with NAFLD and its subset NASH. Results varied between studies, but there was evidence demonstrating improvement in liver enzymes, hepatic inflammation, hepatic steatosis, and hepatic fibrosis. No major adverse effects were noted. Currently, there are no guidelines addressing the use of probiotics in the setting of NAFLD. In conclusion, probiotics appear to be a promising option in the treatment of NAFLD. Future research is necessary to assess the efficacy of probiotics in patients with NAFLD.

Gut dysbiosis-derived exosomes trigger hepatic steatosis by transiting HMGB1 from intestinal to liver in mice

In the past decade, research on the biology of the gut-liver axis has assisted in understanding the basic biology of nonalcoholic fatty liver disease (NAFLD). High mobility group box 1 (HMGB1) protein, in its role as a crucial injury-related molecule, displays a substantial correlation with the degree of liver steatosis. However, its underlying molecular mechanism remains unclear. In the current study of ASC^-/- mice on a high-fat diet (HFD), we observed disorder of the gut microbiota along with abnormal increases in the Firmicutes:Bacteroidetes ratio and in Streptomyces, both of which were detected by 16S rDNA sequencing. Therefore, we investigated the intestinal mucosal injury and analyzed the NAFLD activity score and found that the ASC^-/--HFD group was more severely impaired than the others. Moreover, HMGB1 increased significantly in the intestinal tissue and was co-localized with an exosomal marker. We revealed that HMGB1 was significantly elevated in the exosomes of the ASC^-/--HFD group. It transported by exosomes from the intestine to the liver, thereby triggering hepatic steatosis when dysbiosis. In conclusion, the findings indicated that HMGB1 plays a crucial role in the gut-liver axis mechanism.

Functional Interactions between Gut Microbiota Transplantation, Quercetin, and High-Fat Diet Determine Non-Alcoholic Fatty Liver Disease Development in Germ-Free Mice

SCOPE

Modulation of intestinal microbiota has emerged as a new therapeutic approach for non-alcoholic fatty liver disease (NAFLD). Herein, it is addressed whether gut microbiota modulation by quercetin and intestinal microbiota transplantation can influence NAFLD development.

METHODS AND RESULTS

Gut microbiota donor mice are selected according to their response to high-fat diet (HFD) and quercetin in terms of obesity and NAFLD-related biomarkers. Germ-free recipients displayed metabolic phenotypic differences derived from interactions between microbiota transplanted, diets, and quercetin. Based on the evaluation of hallmark characteristics of NAFLD, it is found that gut microbiota transplantation from the HFD-non-responder donor and the HFD-fed donor with the highest response to quercetin results in a protective phenotype against HFD-induced NAFLD, in a mechanism that involves gut-liver axis alteration blockage in these receivers. Gut microbiota from the HFD-responder donor predisposed transplanted germ-free mice to NAFLD. Divergent protective and deleterious metabolic phenotypes exhibited are related to definite microbial profiles in recipients, highlighting the predominant role of Akkermansia genus in the protection from obesity-associated NAFLD development.

CONCLUSIONS

The results provide scientific support for the prebiotic capacity of quercetin and the transfer of established metabolic profiles through gut microbiota transplantation as a protective strategy against the development of obesity-related NAFLD.

Dynamic distribution of gallbladder microbiota in rabbit at different ages and health states

The internal environment of the gallbladder has been considered extremely unfavorable for bacterial growth, and the microbial profile of the gallbladder still unknown. By high-throughput sequencing of the bacterial 16S rRNA gene, we studied the microbial profile of the gallbladder from healthy rabbits before and after weaning. Moreover, we investigated the difference of microbiota between the gallbladder and gut. Our results showed that the gallbladder was dominantly populated by Firmicutes, Bacteroidetes, Proteobacteria, and Actinobacteria in the phylum throughout the developmental stages of rabbits. The adult rabbits showed higher species richness and exhibited higher bacterial diversity than rabbits before weaning based on the results of alpha diversity. Beta diversity analyses indicated differences in the bacterial community composition between different developmental stages. In the comparison of the gallbladder and feces, Firmicutes and Bacteroidetes were dominant in the phylum, as they were present in about 61% and 21% of the feces, respectively. Conversely, in the gallbladder, Firmicutes was the most dominant (about 41%), and Bacteroidetes and Proteobacteria were present in about 16% and 22% of the gallbladder, respectively. The Unweighted UniFrac Principal Coordinate Analysis results illustrated samples clustered into 2 categories: the gallbladder and feces. Our study might provide a foundation for knowledge on gallbladder microbiota for the first time and a basis for further studies on gallbladder and intestinal health.

Modulation of Gut Microbiota by Lonicera caerulea L. Berry Polyphenols in a Mouse Model of Fatty Liver Induced by High Fat Diet

Polyphenols from the Lonicera caerulea L. berry have shown protective effects on experimental non-alcoholic fatty liver disease (NAFLD) in our previous studies. As endotoxins from gut bacteria are considered to be the major trigger of inflammation in NAFLD, this study aims to clarify the regulatory effects of L. caerulea L. berry polyphenols (LCBP) on gut microbiota in a high fat diet (HFD)-induced mouse model. C57BL/6N mice were fed with a normal diet, HFD, or HFD containing 0.5–1% of LCBP for 45 days. The results revealed that supplementation with LCBP decreased significantly the levels of IL-2, IL-6, MCP-1, and TNF-α in serum, as well as endotoxin levels in both serum and liver in HFD-fed mice. Fecal microbiota characterization by high throughput 16S rRNA gene sequencing revealed that a HFD increased the Firmicutes/Bacteroidetes ratio, and LCBP reduced this ratio by increasing the relative abundance of Bacteroides,Parabacteroides, and another two undefined bacterial genera belonging to the order of Bacteroidales and family of Rikenellaceae, and also by decreasing the relative abundance of six bacterial genera belonging to the phylum Firmicutes, including Staphylococcus, Lactobacillus, Ruminococcus, and Oscillospira. These data demonstrated that LCBP potentially attenuated inflammation in NAFLD through modulation of gut microbiota, especially the ratio of Firmicutes to Bacteroidetes.

The effect of oxidative stress upon intestinal sugar transport: an in vitro study using human intestinal epithelial (Caco-2) cells

The pathogenesis of various gastrointestinal diseases, including gastrointestinal cancers and inflammatory bowel disease, is associated with increased oxidative stress levels. We aimed to investigate the effect of oxidative stress induced by tert-butylhydroperoxide (TBH) on the uptake of 3H-deoxy-d-glucose (3H-DG) and 14C-fructose by the human intestinal Caco-2 cell line. TBH (500 μM; 24 h) increased lipid peroxidation (TBARS) levels and was not cytotoxic. TBH (500 μM; 24 h) increased uptake of both low (SGLT1-mediated) and high concentrations (SGLT1- and GLUT2-mediated) of 3H-DG, but did not affect absorption of 14C-fructose (GLUT2- and GLUT5-mediated). The polyphenol chrysin abolished the increase in TBARS levels and the increase in uptake of both low and high concentrations of 3H-DG induced by TBH. On the other hand, TBH blocked the inhibitory effect of chrysin on 14C-fructose uptake. 3H-DG uptake, but not 14C-fructose uptake, was sensitive to sweet taste receptor (STRs) inhibition (with lactisole). The inhibitory effect of lactisole in relation to uptake of 3H-DG (10 nM) (SGLT1-mediated), but not in relation to uptake of 3H-DG (50 mM) (SGLT1- and GLUT2-mediated), was abolished in the presence of TBH. So, these results show that the stimulatory effect of STRs on SGLT1-mediated transport is dependent on oxidative stress levels. In conclusion, this work shows that uptake of both 3H-DG and 14C-fructose is sensitive to oxidative stress levels. Moreover, it suggests that the three distinct transporters involved in the intestinal absorption of glucose and fructose (SGLT1, GLUT2 and GLUT5) have different sensitivities to oxidative stress levels, SGLT1 being the most sensitive and GLUT5 the least.

Endotoxemia by Porphyromonas gingivalis Injection Aggravates Non-alcoholic Fatty Liver Disease, Disrupts Glucose/Lipid Metabolism, and Alters Gut Microbiota in Mice

Many risk factors related to the development of non-alcoholic fatty liver disease (NAFLD) have been proposed, including the most well-known of diabetes and obesity as well as periodontitis. As periodontal pathogenic bacteria produce endotoxins, periodontal treatment can result in endotoxemia. The aim of this study was to investigate the effects of intravenous, sonicated Porphyromonas gingivalis (Pg) injection on glucose/lipid metabolism, liver steatosis, and gut microbiota in mice. Endotoxemia was induced in C57BL/6J mice (8 weeks old) by intravenous injection of sonicated Pg; Pg was deactivated but its endotoxin remained. The mice were fed a high-fat diet and administered sonicated Pg (HFPg) or saline (HFco) injections for 12 weeks. Liver steatosis, glucose metabolism, and gene expression in the liver were evaluated. 16S rRNA gene sequencing with metagenome prediction was performed on the gut microbiota. Compared to HFco mice, HFPg mice exhibited impaired glucose tolerance and insulin resistance along with increased liver steatosis. Liver microarray analysis demonstrated that 1278 genes were differentially expressed between HFco and HFPg mice. Gene set enrichment analysis showed that fatty acid metabolism, hypoxia, and TNFα signaling via NFκB gene sets were enriched in HFPg mice. Although sonicated Pg did not directly reach the gut, it changed the gut microbiota and decreased bacterial diversity in HFPg mice. Metagenome prediction in the gut microbiota showed enriched citrate cycle and carbon fixation pathways in prokaryotes. Overall, intravenous injection of sonicated Pg caused impaired glucose tolerance, insulin resistance, and liver steatosis in mice fed high-fat diets. Thus, blood infusion of Pg contributes to NAFLD and alters the gut microbiota.

Caloric restriction promotes functional changes involving short-chain fatty acid biosynthesis in the rat gut microbiota

Caloric restriction (CR) is known to promote health and longevity, likely via modification of the gut microbiota (GM). However, functional and metabolic changes induced in the GM during CR are still unidentified. Here, we investigated the short- and long-term effects of CR on the rat GM using a metaproteogenomic approach. We show that a switch from ad libitum (AL) low fat diet to CR in young rats is able to induce rapid and deep changes in their GM metaproteomic profile, related to a reduction of the Firmicutes/Bacteroidetes ratio and an expansion of lactobacilli. Specifically, we observed a significant change in the expression of the microbial enzymes responsible for short-chain fatty acid biosynthesis, with CR boosting propionogenesis and limiting butyrogenesis and acetogenesis. Furthermore, these CR-induced effects were maintained up to adulthood and started to be reversed after a short-term diet change. We also found that CR alters the abundance of an array of host proteins released in stool, mainly related to epithelial barrier integrity and inflammation. Hence, our results provide thorough information about CR-induced modifications to GM and host functional activity, and might constitute the basis for novel GM-based approaches aimed at monitoring the effectiveness of dietary interventions.

Reduction of Liver Span and Parameters of Inflammation in Nonalcoholic Fatty Liver Disease Patients Treated with Lycosome Formulation of Phosphatidylcholine: A Preliminary Report

Twenty-nine newly diagnosed individuals with Nonalcoholic Fatty Liver Disease (NAFLD) remaining on habitual dietary regimen were supplemented with regular or lycosome formulations of phosphatidylcholine (PC) during a pilot, randomized, double-blinded clinical study. After two months of oral PC intake (450 mg daily) the liver size as well as serum levels of hepatic enzymes and markers of inflammation were evaluated by ultrasonography and biochemical analysis. It was shown that there was a statistically significant reduction of medians for the Mid-Clavicular liver size from 16.0 cm (95/5% CI: 17.1/15.5) to 15.1 cm (95/5% CI: 17.2/14.4, P = 0.021) in participants ingesting the lycosome-formulated PC (L-PC) whereas regular formulation of PC (R-PC) had only a marginal effect on this parameter (P = 0.044). A similar tendency was observed in the Mid-Sternal liver size. Moreover, there was a reduction of medians for ALT values at the end point of the study (P = 0.026) after ingestion of L-PC, while R-PC had no statistically significant effect. On the other hand, ingestion of both formulations was accompanied by reductions in values for Inflammatory Oxidative Damage (IOD) and oxidized LDL in serum. However, L-PC had superior activity in these terms, presumably due to the presence of lycopene, a powerful antioxidant, in the L-PC-Lycosome structure. C-reactive protein level was moderately decreased (reduction of medians from 6.5 [95/5% CI: 7.7/5.8] mg/L to 5.1 [95/5% CI: 5.6/4.3] mg/L) only after ingestion of L-PC. The greater efficacy of L-PC seen in NAFLD volunteers may reflect improved bioavailability of PC owing to better protection of the microencapsulated PC from gastrointestinal enzymes and possibly enhanced hepatic delivery of L-PC particles.

The Potential Effect of Chinese Herbal Formula Hongqijiangzhi Fang in Improving NAFLD: Focusing on NLRP3 Inflammasome and Gut Microbiota

The present study investigates the potential therapeutic mechanism underlying the effects of the Chinese herbal formula Hongqijiangzhi Fang (HJF) on nonalcoholic fatty liver disease (NAFLD) in rats. Male Sprague Dawley (SD) rats were randomly divided into 4 groups (n = 8): control group was fed a normal diet, three other groups were fed high-fat diets (HFD), and the two treatment groups were intragastrically given a compound probiotic or HJF during the molding time. After 16 w, related indices were detected. The results showed that HJF significantly reduced abdominal aorta serum cholesterol (TC), triglyceride (TG), low-density lipoprotein (LDL), IL-1β, and IL-18, portal venous serum lipopolysaccharide (LPS), and liver TC and TG levels in HFD-fed rats. HJF ameliorated hepatic steatosis in the liver and improved the intestinal barrier in HFD-fed rats. Activation of the NLRP3 inflammasome was reduced by HJF in HFD-fed rats. Additionally, the abundances of A. muciniphila (Verrucomicrobiaceae), F. rappini (Helicobacteraceae), and Enterobacteriaceae bacteria significantly decreased in HJF-treated HFD-fed rats. In conclusion, these result suggested that the Chinese herbal formula HJF reduced hepatic steatosis maybe through decreasing certain gut bacteria (such as Enterobacteriaceae bacteria and F. rappini), alleviating intestinal endotoxemia and reducing NLRP3 inflammasome activation.

Review article: the gut microbiome as a therapeutic target in the pathogenesis and treatment of chronic liver disease

BACKGROUND

Mortality from chronic liver disease is rising exponentially. The liver is intimately linked to the gut via the portal vein, and exposure to gut microbiota and their metabolites translocating across the gut lumen may impact upon both the healthy and diseased liver. Modulation of gut microbiota could prove to be a potential therapeutic target.

AIM

To characterise the changes in the gut microbiome that occur in chronic liver disease and to assess the impact of manipulation of the microbiome on the liver.

METHODS

We conducted a PubMed search using search terms including 'microbiome', 'liver' and 'cirrhosis' as well as 'non-alcoholic fatty liver disease', 'steatohepatitis', 'alcohol' and 'primary sclerosing cholangitis'. Relevant articles were also selected from references of articles and review of the ClinicalTrials.gov website.

RESULTS

Reduced bacterial diversity, alcohol sensitivity and the development of gut dysbiosis are seen in several chronic liver diseases, including non-alcoholic fatty liver disease, alcohol-related liver disease and primary sclerosing cholangitis. Perturbations in gut commensals could lead to deficient priming of the immune system predisposing the development of immune-mediated diseases. Furthermore, transfer of stool from an animal with the metabolic syndrome may induce steatosis in a healthy counterpart. Patients with cirrhosis develop dysbiosis, small bowel bacterial overgrowth and increased gut wall permeability, allowing bacterial translocation and uptake of endotoxin inducing hepatic and systemic inflammation.

CONCLUSIONS

Manipulation of the gut microbiota with diet, probiotics or faecal microbiota transplantation to promote the growth of "healthy" bacteria may ameliorate the dysbiosis and alter prognosis.

Balancing Herbal Medicine and Functional Food for Prevention and Treatment of Cardiometabolic Diseases through Modulating Gut Microbiota

It has become apparent that gut microbiota is closely associated with cardiometabolic diseases (CMDs), and alteration in microbiome compositions is also linked to the host environment. Next generation sequencing (NGS) has facilitated in-depth studies on the effects of herbal medicine and functional food on gut microbiota. Both herbal medicine and functional food contain fiber, polyphenols and polysaccharides, exerting prebiotics-like activities in the prevention and treatment of CMDs. The administrations of herbal medicine and functional food lead to increased the abundance of phylum Bacteroidetes, and genus Akkermansia, Bifidobacteria, Lactobacillus, Bacteroides and Prevotella, while reducing phylum Firmicutes and Firmicutes/Bacteroidetes ratio in gut. Both herbal medicine and functional food interact with gut microbiome and alter the microbial metabolites including short-chain fatty acids (SCFAs), bile acids (BAs) and lipopolysaccharides (LPS), which are now correlated with metabolic diseases such as type 2 diabetes (T2D), obesity and non-alcoholic fatty liver disease (NAFLD). In addition, trimethylamine (TMA)-N-oxide (TMAO) is recently linked to atherosclerosis (AS) and cardiovascular disease (CVD) risks. Moreover, gut-organs axes may serve as the potential strategy for treating CMDs with the intervention of herbal medicine and functional food. In summary, a balance between herbal medicine and functional food rich in fiber, polyphenols and polysaccharides plays a vital role in modulating gut microbiota (phylum Bacteroidetes, Firmicutes and Firmicutes/Bacteroidetes ratio, and genus Akkermansia, Bifidobacteria, Lactobacillus, Bacteroides and Prevotella) through SCFAs, BAs, LPS and TMAO signaling regarding CMDs. Targeting gut-organs axes may serve as a new therapeutic strategy for CMDs by herbal medicine and functional food in the future. This review aims to summarize the balance between herbal medicine and functional food utilized for the prevention and treatment of CMDs through modulating gut microbiota.

Non-Alcoholic Fatty Liver Disease (NAFLD) and Non-Alcoholic Steatohepatitis (NASH) in HIV

Abnormal liver enzymes (LE) are common in patients infected with the human immunodeficiency virus (HIV) even in the absence of viral hepatitis or alcohol abuse. With availability of antiretroviral combination therapy, life expectancy has improved dramatically and as a consequence the spectrum of liver disease is changing. Increased reports on the development of non-alcoholic fatty liver disease (NAFLD) or non-alcoholic steatohepatitis (NASH) in HIV coinfected patients raise questions around prevalence, clinical manifestations, and clinical outcome of these liver diseases in HIV coinfection. Moreover, the potential impact of combination antiretroviral therapy as well as direct HIV effects on the emergence of non-alcoholic fatty liver disease needs to be explored. This review summarizes the recent literature on NAFLD and NASH in HIV.

The Effect of Nonnutritive Sweeteners Added to a Liquid Diet on Volume and Caloric Intake and Weight Gain in Rats

OBJECTIVE

Long-term effects of diet beverage consumption on the regulation of caloric intake is unclear. The goal of this study was to investigate whether the chronic intake of a liquid diet with nonnutritive sweeteners (NNS) would lead to greater appetite and weight gain.

METHODS

Wistar rats were fed a liquid diet (Osmolite) sweetened with nutritive sweetener (NS; sucrose) and NNS (stevia and saccharin) or a nonsweetened control. Intakes and weight gain were measured. Phases 1 and 2 investigated sweetness preference, phase 3 used diets with or without sweeteners, and phase 4 measured the effect on volume of food and caloric intake of alternating between NNS, NS, and control diets.

RESULTS

In phase 1, rats preferred: stevia, 0.10%; saccharin, 0.20%; and sucrose, 15%. In phase 2, rats preferred the sweetened diet over the control. In phase 3, rats fed the NS diet consumed less volume and more calories but gained less weight. In phase 4, when altering diet from NNS to NS, no differences were observed in appetite or weight gain.

CONCLUSIONS

Using sucrose-sweetened diet as a control, increased weight gain with the ingestion of NNS was observed. However, using a nonsweetened control, neither increased caloric intake nor weight gain occurred with NNS intake. Alternating diets between NNS, NS, and control did not affect the appetite.

Apolipoprotein O expression in mouse liver enhances hepatic lipid accumulation by impairing mitochondrial function

Apolipoprotein O (ApoO) was recently observed in the cellular mitochondrial inner membrane, which plays a role in mitochondrial function and is associated with myocardiopathy. Empirical information on the physiological functions of apoO is therefore limited. In this study, we aimed to elucidate the effect of apoO on hepatic fatty acid metabolism. An adenoviral vector expressing hApoO was constructed and introduced into chow diet and high-fat diet induced mice and the L02 human hepatoma cell line. High levels of hApoO mRNA and protein were detected in the liver, and the expression of lipid metabolism genes was significantly altered compared with negative controls. The liver function indices (serum ALT and AST) were clearly elevated, and the ultrastructure of cellular mitochondria was distinctly altered in the liver after apoO overexpression. Further, mitochondrial membrane potential decreased with hApoO treatment in L02 cells. These results establish a link between apoO and lipid accumulation and could suggest a new pathway for regulating non-alcoholic fatty liver disease progression.