Non-alcoholic fatty liver disease and obesity: the role of the gut bacteria

Impact of urbanization on gut microbiome mosaics across geographic and dietary contexts

This study provides a comprehensive assessment of how urban-rural divides influence gut microbial diversity and composition across the distinct geographical landscapes of Kazakhstan, elucidating the intricate interplay between lifestyle, environment, and gut microbiome. In this prospective cohort study, we enrolled 651 participants from urban centers and rural settlements across Kazakhstan, following ethical approval and informed consent. Comprehensive demographic, dietary, and stool sample data were collected. 16S rRNA gene sequencing and shotgun metagenomics techniques were employed to delineate the intricate patterns of the gut microbiome. A rigorous statistical framework dissected the interplay between urbanization gradients, geography, dietary lifestyles, and microbial dynamics. Our findings demonstrate a stark microbial divide between urban and rural gut ecosystems. The study found significant differences in gut microbiome diversity and composition between urban and rural populations in Kazakhstan. Urban microbiomes exhibited reduced diversity, higher Firmicutes/Bacteroidetes ratios, and increased prevalence of genera Coprococcus and Parasutterella. In contrast, rural populations had greater microbial diversity and abundance of Ligilactobacillus, Sutterella, and Paraprevotella. Urbanization also influenced dietary patterns, with urban areas consuming more salt, cholesterol, and protein, while rural areas had diets richer in carbohydrates and fiber. The study also identified distinct patterns in the prevalence of antibiotic resistance genes and virulence factors between urban and rural gut microbiomes. This study sheds light on how urbanization may be deeply involved in shaping the intricate mosaic of the gut microbiome across Kazakhstan's diverse geographical and dietary landscapes, underscoring the complex interplay between environmental exposures, dietary lifestyles, and the microbial residents inhabiting our intestines.

IMPORTANCE

The study examined gut microbiome composition across diverse geographical locations in Kazakhstan, spanning urban centers and rural settlements. This allows for thoroughly investigating how urbanization gradients and geographic factors shape the gut microbiome. The study's examination of the gut resistome and prevalence of virulence-associated genes provide essential insights into the public health implications of urbanization-driven microbiome alterations. Collecting comprehensive demographic, dietary, and stool sample data enables the researchers to better understand the relationships between urbanization, nutritional patterns, and gut microbiome composition. The findings have important implications for understanding how urbanization-driven microbiome changes may impact human health and well-being, paving the way for tailored interventions to restore a balanced gut microbial ecology.

The Ambiguous Correlation of Blautia with Obesity: A Systematic Review

Obesity is a complex and multifactorial disease with global epidemic proportions, posing significant health and economic challenges. Whilst diet and lifestyle are well-established contributors to the pathogenesis, the gut microbiota's role in obesity development is increasingly recognized. Blautia, as one of the major intestinal bacteria of the Firmicutes phylum, is reported with both potential probiotic properties and causal factors for obesity in different studies, making its role controversial. To summarize the current understanding of the Blautia-obesity correlation and to evaluate the evidence from animal and clinical studies, we used "Blautia" AND "obesity" as keywords searching through PubMed and SpringerLink databases for research articles. After removing duplicates and inadequate articles using the exclusion criteria, we observed different results between studies supporting and opposing the beneficial role of Blautia in obesity at the genus level. Additionally, several studies showed probiotic effectiveness at the species level for Blautia coccoides, B. wexlerae, B. hansenii, B. producta, and B. luti. Therefore, the current evidence does not demonstrate Blautia's direct involvement as a pathogenic microbe in obesity development or progression, which informs future research and therapeutic strategies targeting the gut Blautia in obesity management.

Lonicerae flos polysaccharides improve nonalcoholic fatty liver disease by activating the adenosine 5'-monophosphate-activated protein kinase pathway and reshaping gut microbiota

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is the most common cause of liver cirrhosis and cancer. Lonicerae flos polysaccharides (LPs) have been shown to be effective in treating metabolic diseases; however, the therapeutic effects and underlying molecular mechanisms of LPs in NAFLD remain unclear.

PURPOSE

The objective of this study was to investigate the morphological characterization of Lonicerae flos polysaccharides (LPs) and the mechanism of LPs in relieving NAFLD.

METHODS

The morphology of LPs was observed using atomic force microscopy (AFM), X-ray diffraction (XRD), thermal weight (TG), and thermal weight derivative (DTG); NAFLD mice were treated with LPs at the same time as they were induced with a Western diet, and then the indexes related to glycolipid metabolism, fibrosis, inflammation, and autophagy in the serum and liver of the mice were detected.

RESULTS

The atomic force microscope analysis results indicated that the LPs displayed sugar-chain aggregates, exhibited an amorphous structure, and were relatively stable in thermal cracking at 150 °C. It was also found that LPs exerted therapeutic effects in NAFLD. The LPs prevented high-fat and -cholesterol diet-induced NAFLD progression by regulating glucose metabolism dysregulation, insulin resistance, lipid accumulation, inflammation, fibrosis, and autophagy. Adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK) inhibitor compound C abrogated LP-induced hepatoprotection in mice with NAFLD. The LPs further treated NAFLD by reshaping the structure of the gut microbiota, in which Desulfovibrio bacteria plays a key roles.

CONCLUSION

Lonicerae flos polysaccharides exert protective effects against NAFLD in mice by improving the structure of the intestinal flora and activating the AMPK signaling pathway. © 2023 Society of Chemical Industry.

Insights into the role of vitamin D in targeting the culprits of non-alcoholic fatty liver disease

Vitamin D (VD) is a secosteroid hormone that is renowned for its crucial role in phospho-calcium homeostasis upon binding to the nuclear vitamin D receptor (VDR). Over and above, the pleiotropic immunomodulatory, anti-inflammatory, and metabolic roles VD plays in different disease settings started to surface in the past few decades. On the other hand, a growing body of evidence suggests a correlation between non-alcoholic fatty liver disease (NAFLD) and its progressive inflammatory form non-alcoholic steatohepatitis (NASH) with vitamin D deficiency (VDD) owing to the former's ingrained link with obesity and metabolic syndrome. Accordingly, a better understanding of the contribution of disrupted VDR signalling to NAFLD incidence and progression would provide further insights into its diagnosis, treatment modalities, and prognosis. This is especially significant as, hitherto, no drug for NAFLD has been approved. This review, therefore, sought to set forth the likely contribution of VDR signalling in NAFLD and how it might influence its multiple drivers.

Oroxin B improves metabolic-associated fatty liver disease by alleviating gut microbiota dysbiosis in a high-fat diet-induced rat model

Metabolic-associated fatty liver disease (MAFLD) has become a common chronic liver disease, but there is no FDA-approved drug for MAFLD treatment. Numerous studies have revealed that gut microbiota dysbiosis exerts a crucial effect on MAFLD progression. Oroxin B is a constituent of the traditional Chinese medicine Oroxylum indicum (L.) Kurz. (O. indicum), which has the characteristics of low oral bioavailability but high bioactivity. However, the mechanism through which oroxin B improves MAFLD by restoring the gut microbiota balance remains unclear. To this end, we assessed the anti-MAFLD effect of oroxin B in HFD-fed rats and investigated the underlying mechanism. Our results indicated that oroxin B administration reduced the lipid levels in the plasma and liver and lowered the lipopolysaccharide (LPS), interleukin 6 (IL-6), and tumor necrosis factor-α (TNF-α) levels in the plasma. Moreover, oroxin B alleviated hepatic inflammation and fibrosis. Mechanistically, oroxin B modulated the gut microbiota structure in HFD-fed rats by increasing the levels of Lactobacillus, Staphylococcus, and Eubacterium and decreasing the levels of Tomitella, Bilophila, Acetanaerobacterium, and Faecalibaculum. Furthermore, oroxin B not only suppressed Toll-like receptor 4-inhibitor kappa B-nuclear factor kappa-B-interleukin 6/tumor necrosis factor-α (TLR4-IκB-NF-κB-IL-6/TNF-α) signal transduction but also strengthened the intestinal barrier by elevating the expression of zonula occludens 1 (ZO-1) and zonula occludens 2 (ZO-2). In summary, these results demonstrate that oroxin B could alleviate hepatic inflammation and MAFLD progression by regulating the gut microbiota balance and strengthening the intestinal barrier. Hence, our study suggests that oroxin B is a promising effective compound for MAFLD treatment.

Nobiletin Ameliorates Nonalcoholic Fatty Liver Disease by Regulating Gut Microbiota and Myristoleic Acid Metabolism

Disturbance of the gut microbiota plays a critical role in the development of nonalcoholic fatty liver disease (NAFLD). Increasing evidence supports that natural products may serve as prebiotics to regulate the gut microbiota in the treatment of NAFLD. In the present study, the effect of nobiletin, a naturally occurring polymethoxyflavone, on NAFLD was evaluated, and metabolomics, 16S rRNA gene sequencing, and transcriptomics analysis were performed to determine the underlying mechanism of nobiletin, and the key bacteria and metabolites screened were confirmed by in vivo experiment. Nobiletin treatment could significantly reduce lipid accumulation in high-fat/high-sucrose diet-fed mice. 16S rRNA analysis demonstrated that nobiletin could reverse the dysbiosis of gut microbiota in NAFLD mice and nobiletin could regulate myristoleic acid metabolism, as revealed by untargeted metabolomics analysis. Treatment with the bacteria Allobaculum stercoricanis, Lactobacillus casei, or the metabolite myristoleic acid displayed a protective effect on liver lipid accumulation under metabolic stress. These results indicated that nobiletin might target gut microbiota and myristoleic acid metabolism to ameliorate NAFLD.

The Intersection of COVID-19 and Metabolic-Associated Fatty Liver Disease: An Overview of the Current Evidence

The global population is currently experiencing the impact of the SARS-CoV-2 coronavirus, which has caused the Coronavirus Disease 2019 (COVID-19) pandemic. With our profound comprehension of COVID-19, encompassing the involvement sequence of the respiratory tract, gastrointestinal system, and cardiovascular apparatus, the multiorgan symptoms of this infectious disease have been discerned. Metabolic-associated fatty liver disease (MAFLD), formerly known as non-alcoholic fatty liver disease (NAFLD), is a pervasive public health concern intricately linked with metabolic dysregulation and estimated to afflict one-fourth of the global adult population. The burgeoning focus on the association between COVID-19 and MAFLD is justified by the potential role of the latter as a risk factor for both SARS-CoV-2 infection and the subsequent emergence of severe COVID-19 symptoms. Investigations have suggested that changes in both innate and adaptive immune responses among MAFLD patients may play a role in determining the severity of COVID-19. The remarkable similarities observed in the cytokine pathways implicated in both diseases imply the existence of shared mechanisms governing the chronic inflammatory responses characterizing these conditions. The effect of MAFLD on the severity of COVID-19 illness remains uncertain, as indicated by conflicting results in cohort investigations.

A Multidisciplinary Approach and Current Perspective of Nonalcoholic Fatty Liver Disease: A Systematic Review

In recent times, nonalcoholic fatty liver disease (NAFLD) has been considered one of the major causes of liver disease across the world. NAFLD is defined as the deposition of triglycerides in the liver and is associated with obesity and metabolic syndrome. Hyperinsulinemia, insulin resistance (IR), fatty liver, hepatocyte injury, unbalanced proinflammatory cytokines, mitochondrial dysfunction, oxidative stress, liver inflammation, and fibrosis are the main pathogenesis in NAFLD. Recent studies suggest that the action of intestinal microbiota through chronic inflammation, increased intestinal permeability, and energy uptake plays a vital role in NAFLD. Moreover, polycystic ovarian syndrome also causes NAFLD development through IR. Age, gender, race, ethnicity, sleep, diet, sedentary lifestyle, and genetic and epigenetic pathways are some contributing factors of NAFLD that can exacerbate the risk of liver cirrhosis and hepatocellular carcinoma (HCC) and eventually lead to death. NAFLD has various presentations, including fatigue, unexplained weight loss, bloating, upper abdominal pain, decreased appetite, headache, anxiety, poor sleep, increased thirst, palpitation, and a feeling of warmth. Some studies have shown that NAFLD with severe coronavirus disease 2019 (COVID-19) has poor outcomes. The gold standard for NAFLD diagnosis is liver biopsy. Other diagnostic tools are imaging tests, serum biomarkers, microbiota markers, and tests for extrahepatic complications. There are no specific treatments for NAFLD. Therefore, the main concern for NAFLD is treating the comorbid conditions such as anti-diabetic agents for type 2 diabetes mellitus, statins to reduce HCC progression, antioxidants to prevent hepatocellular damage, and bariatric surgery for patients with a BMI of >40 kg/m² and >35 kg/m² with comorbidities. Lifestyle and dietary changes are considered preventive strategies against NAFLD advancement. Inadequate treatment of NAFLD further leads to cardiac consequences, sleep apnea, chronic kidney disease, and inflammatory bowel disease. In this systematic review, we have briefly discussed the risk factors, pathogenesis, clinical features, and numerous consequences of NAFLD. We have also reviewed various guidelines for NAFLD diagnosis along with existing therapeutic strategies for the management and prevention of the disease.

Multifunctional Selenium Nanoparticles with Different Surface Modifications Ameliorate Neuroinflammation through the Gut Microbiota-NLRP3 Inflammasome-Brain Axis in APP/PS1 Mice

Neuroinflammation plays a critical role in Alzheimer's disease (AD). However, it is still unknown if neuroinflammation can be effectively treated using selenium nanoparticles (SeNPs) with different surface modifications. In this study, SeNPs were coated with dihydromyricetin (DMY), a natural polyphenol, to obtain DMY@SeNPs. Given that DMY@SeNPs are unstable under physiological conditions, they were decorated step-by-step with chitosan (CS/DMY@SeNPs) and with the blood brain barrier (BBB) targeting peptide Tg (TGNYKALHPHNG) to yield Tg-CS/DMY@SeNPs, which significantly reduced the aggregation of Aβ and improved the anti-inflammatory effects of SeNPs in vitro. The mechanisms of CS/DMY@SeNPs and Tg-CS/DMY@SeNPs on regulating neuroinflammation are different. Only Tg-CS/DMY@SeNPs can cross the BBB; therefore, Tg-CS/DMY@SeNPs more successfully inhibited Aβ aggregation and reduced inflammatory cytokine secretion via the NF-κB pathway in the brain of APP/PS1 mice compared to CS/DMY@SeNPs. Furthermore, both types of nanoparticles, however, were able to repair the gut barrier and regulate the population of inflammatory-related gut microbiota such as Bifidobacterium, Dubosiella, and Desulfovibrio. Of note, the relative abundance of Gordonibacter was only enhanced by Tg-CS/DMY@SeNPs, thereby downregulating the protein expression of the NLRP3 inflammasome and the concentrations of serum inflammatory factors. This demonstrates that Tg-CS/DMY@SeNPs ameliorate neuroinflammation through the gut microbiota-NLRP3 inflammasome-brain axis. Overall, our data suggest that Tg-CS/DMY@SeNPs are an ideal drug candidate for AD treatment.

Exploring the Path of Mediterranean Diet, Non-Alcoholic Fatty Liver Disease (NAFLD) and Inflammation towards 10-Year Cardiovascular Disease (CVD) Risk: The ATTICA Study 10-Year Follow-Up (2002-2012)

Background: Non-alcoholic fatty liver disease (NAFLD) is the leading cause of liver disease, affecting ~30% of the population and increasing CVD. This study aimed to explore the direct, indirect and combined effects of Mediterranean diet, NAFLD and inflammation on the 10-year CVD risk in a healthy adult population. Methods: Using baseline and 10-year follow-up data from the ATTICA study, adherence to Mediterranean diet was measured using MedDietScore, and presence of NAFLD at baseline was assessed using the fatty liver index (FLI). Participants’ 10-year CVD outcomes were recorded and C-reactive protein (CRP) was used as a surrogate marker for inflammation. The direct and indirect roles of these factors were explored using logistic regression models and the pathways between them were analysed using a structural equation model (SEM). Results: NAFLD prevalence was 22.9% and its presence was 17% less likely for every unit increase in MedDietScore. NAFLD presence at baseline was associated with increased 10-year CVD incidence (39.4% vs. 14.5%, p = 0.002), but when adjusted for MedDietScore, NAFLD was not an independent predictor of 10-year CVD risk. MedDietScore was an independent protective factor of 10-year CVD risk (OR = 0.989, 95% CI: 0.847, 0.935), when adjusted for NAFLD at baseline, age, gender, sedentary lifestyle and other confounders. Further exploration using SEM showed that MedDietScore was associated with CVD risk directly even when inflammation as CRP was introduced as a potential mediator. Conclusion: FLI as a proxy measure of NAFLD is a strong predictor of 10-year CVD risk, and this prognostic relationship seems to be moderated by the level of adherence to Mediterranean diet. Adherence to Mediterranean diet remained an independent and direct CVD risk factor irrespective of NAFLD status and CRP.

Dose-Response Associations of Metabolic Score for Insulin Resistance Index with Nonalcoholic Fatty Liver Disease among a Nonobese Chinese Population: Retrospective Evidence from a Population-Based Cohort Study

Purpose

This study is aimed at investigating the association between the metabolic score for insulin resistance (METS-IR) index and nonalcoholic fatty liver disease (NAFLD) in the nonobese population and its predictive value.

Methods

10730 nonobese subjects were selected from longitudinal cohort research conducted from January 2010 to December 2014. Cox proportional hazards models were employed to assess the relationship between METS-IR and new-onset NAFLD. Generalized additive models were used to identify nonlinear relationships. In addition, we performed subgroup analyses and interaction tests. The time-dependent receiver operating curve (ROC) and area under the ROC (AUC) were utilized to measure the discriminatory ability of METS-IR for new-onset NAFLD. Beyond clinical risk factors, the incremental predictive value of METS-IR was appraised using integrated discrimination improvement (IDI), C-index, and net reclassification index (NRI).

Results

Over a median period of 804.50 days of follow-up, 1859 (17.33%) participants had a new onset of NAFLD. After adjusting for confounders, the HR for new-onset NAFLD in the Q4 group was 6.40 compared with the Q1 group. When METS-IR was considered a continuous variable, the risk of NAFLD increased by 34% for every 1 SD increase in METS-IR. The smoothing curve shows the dose-response relationship between METS-IR and the presence of new-onset NAFLD. Using a two-piecewise linear regression model, we derived a METS-IR inflection point of 36. HRs were 1.31 on the left side of the inflection point and 1.04 on the right side of the inflection point (log-likelihood ratio test, P < 0.001). Subgroup analyses and interaction tests revealed an interaction between gender and SBP in the association between METS-IR and new-onset NAFLD. In the subgroup analysis of gender and SBP, we observed a higher risk of new-onset NAFLD in men and in those with abnormal SBP levels. We evaluated the ability of METS-IR to identify new-onset NAFLD at different time points. The AUCs at 1, 2, 3, and 4 years were 0.784, 0.756, 0.758, and 0.752, respectively, which represent good discrimination of new-onset NAFLD. The addition of METS-IR greatly improved the reclassification and differentiation of clinical risk factors, with an NRI of 0.276 and an IDI of 0.068. In addition, the addition of METS-IR increased the C-index from 0.719 to 0.771.

Conclusion

In a nonobese Chinese population, elevated METS-IR was independently associated with an enhanced risk of NAFLD development and a dose-response relationship existed. In addition, METS-IR might be a reliable indicator for screening individuals at risk for early NAFLD, especially in nonobese populations.

The Synbiotic Combination of Akkermansia muciniphila and Quercetin Ameliorates Early Obesity and NAFLD through Gut Microbiota Reshaping and Bile Acid Metabolism Modulation

Gut microbiota plays a key role in obesity and non-alcoholic fatty liver disease (NAFLD), so synbiotics could be a therapeutic alternative. We aim to evaluate a nutritional intervention together with the administration of the bacteria Akkermansia muciniphila and the antioxidant quercetin in an in vivo model of early obesity and NAFLD. 21-day-old rats were fed with control or high-fat diet for six weeks. Then, all animals received control diet supplemented with/without quercetin and/or A. muciniphila for three weeks. Gut microbiota, NAFLD-related parameters, circulating bile acids (BAs) and liver gene expression were analyzed. The colonization with A. muciniphila was associated with less body fat, while synbiotic treatment caused a steatosis remission, linked to hepatic lipogenesis modulation. The synbiotic promoted higher abundance of Cyanobacteria and Oscillospira, and lower levels of Actinobacteria, Lactococcus, Lactobacillus and Roseburia. Moreover, it favored elevated unconjugated hydrophilic BAs plasma levels and enhanced hepatic expression of BA synthesis and transport genes. A. muciniphila correlated with circulating BAs and liver lipid and BA metabolism genes, suggesting a role of this bacterium in BA signaling. Beneficial effects of A. muciniphila and quercetin combination are driven by gut microbiota modulation, the shift in BAs and the gut-liver bile flow enhancement.

Desulfovibrio vulgaris, a potent acetic acid-producing bacterium, attenuates nonalcoholic fatty liver disease in mice

The emerging evidence supports the use of prebiotics like herb-derived polysaccharides for treating nonalcoholic fatty liver disease (NAFLD) by modulating gut microbiome. The present study was initiated on the microbiota-dependent anti-NAFLD effect of Astragalus polysaccharides (APS) extracted from Astragalus mongholicus Bunge in high-fat diet (HFD)-fed mice. However, the exact mechanisms underlying the beneficial effects of APS on NAFLD formation remain poorly understood.Co-housing experiment was used to assess the microbiota dependent anti-NAFLD effect of APS. Then, targeted metabolomics and metagenomics were adopted for determining short-chain fatty acids (SCFAs) and bacteria that were specifically enriched by APS. Further in vitro experiment was carried out to test the capacity of SCFAs-producing of identified bacterium. Finally, the anti-NAFLD efficacy of identified bacterium was tested in HFD-fed mice.Our results first demonstrated the anti-NAFLD effect of APS in HFD-fed mice and the contribution of gut microbiota. Moreover, our results indicated that SCFAs, predominantly acetic acid were elevated in APS-supplemented mice and ex vivo experiment. Metagenomics revealed that D. vulgaris from Desulfovibrio genus was not only enriched by APS, but also a potent generator of acetic acid, which showed significant anti-NAFLD effects in HFD-fed mice. In addition, D. vulgaris modulated the hepatic gene expression pattern of lipids metabolism, particularly suppressed hepatic fatty acid synthase (FASN) and CD36 protein expression.Our results demonstrate that APS enriched D. vulgaris is effective on attenuating hepatic steatosis possibly through producing acetic acid, and modulation on hepatic lipids metabolism in mice. Further studies are warranted to explore the long-term impacts of D. vulgaris on host metabolism and the underlying mechanism.

Potential contribution of the gut microbiota to hypoglycemia after gastric bypass surgery

Obesity has become a global health problem. Lifestyle modification and medical treatment only appear to yield short-term weight loss. Roux-en-Y gastric bypass (RYGB) is the most popular bariatric procedure, and it sustains weight reduction and results in the remission of obesity-associated comorbidities for obese individuals. However, patients who undergo this surgery may develop hypoglycemia. To date, the diagnosis is challenging and the prevalence of post-RYGB hypoglycemia (PRH) is unclear. RYGB alters the anatomy of the upper gastrointestinal tract and has a combined effect of caloric intake restriction and nutrient malabsorption. Nevertheless, the physiologic changes after RYGB are complex. Although hyperinsulinemia, incretin effects, dysfunction of β-cells and α-cells, and some other factors have been widely investigated and are reported to be possible mediators of PRH, the pathogenesis is still not completely understood. In light of the important role of the gut microbiome in metabolism, we hypothesized that the gut microbiome might also be a critical link between RYGB and hypoglycemia. In this review, we mainly highlight the current possible factors predisposing individuals to PRH, particularly related to the gut microbiota, which may yield significant insights into the intestinal regulation of glucose metabolic homeostasis and provide novel clues to improve the treatment of type 2 diabetes mellitus.

Association between Inflammatory Biomarkers and Nutritional Status in Fatty Liver

The prevalence and progression of non-alcoholic fatty liver disease (NAFLD) is mediated via several factors correlating with hepatic necroinflammation (adipokines/cytokines). This study was performed to analyze the level of inflammatory markers according to the presence of NAFLD and to identify related nutritional factors. A total of 80 adults were classified into 2 groups (healthy and NAFLD), and their body composition, blood tests, and eating habits were evaluated. In addition, inflammatory markers (adiponectin, high-sensitivity C-reactive protein [CRP], and tumor necrosis factor-alpha [TNF-α]), nutrient intake status, and dietary quality were compared. The quality of diet was assessed according to the nutrient adequacy ratio and the mean adequacy ratio (MAR). The NAFLD group had a higher body mass index (p < 0.001) than the healthy group and also carried significantly higher CRP levels (p < 0.001) but lower adiponectin (p = 0.001). TNF-α levels increased significantly with fatty liver grade (p = 0.023). The NAFLD group showed significantly higher intake of energy, carbohydrates, iron, sodium, vitamin A and saturated fatty acids, but significantly lower intake of zinc and vitamin E than the healthy group. The MAR values were slightly higher in the NAFLD group but without any significant difference. The levels of adiponectin and vitamin E showed a significant inverse correlation (p < 0.05). Nutritional management of NAFLD patients is important, and the intake of antioxidant and anti-inflammatory nutrients such as zinc and vitamin E should be emphasized.

New mechanism of neuroinflammation in Alzheimer's disease: The activation of NLRP3 inflammasome mediated by gut microbiota

Alzheimer's disease (AD) is a central degenerative disease characterized by cognitive impairment. Polymerization of β-amyloid has been reported to cause the entanglement of nerve cells, leading to the progressive loss of nerve cells. Accumulative studies have confirmed the important roles of neuroinflammation in the development of AD. In this study, the gut microbiota from AD patients were transplanted into APP/PS1 double transgenic mice. As a result, the expression of NLRP3 was increased in the intestinal tract of mice, and the expression levels of inflammatory factors in peripheral blood were also increased. Consistently, the cognitive impairment was more severe in mice receiving gut microbiota from AD patients than those did not, with activation of microglia in the central hippocampus of mice, and increased expression of neuroinflammatory factors. In APP/PS1 mice transplanted with gut microbiota from AD patients, transplantation of healthy human gut microbiota or oral administration of minocycline was further used to improve the composition of gut microbiota. Consequently, the intestinal expression of NLRP3 was down-regulated, the cognitive ability of mice was improved, the activation of microglia in central hippocampus was suppressed and the expression of neuroinflammatory factors was also down-regulated. After transplantation of gut microbiota from AD patients in C57BL/6 mice, the intestinal expression of NLRP3 was up-regulated. Although the cognitive ability of mice was not significantly changed, the microglia in the hippocampus of mice were still activated and the expression of inflammatory factors was up-regulated. In this study, we found that gut microbiota in AD patients could induce the activation of NLRP3 inflammasome in the intestinal tract of mice, subsequently causing the release of inflammatory factors. The absorption and circulation of inflammatory factors through the intestinal tract could further aggravate the inflammation in the nervous tissues and the activation of microglia. Therefore, improving the composition of gut microbiota in AD patients can further attenuate neuroinflammation, which is considered as a novel idea for AD treatment.

Evaluation of a Dual-Acting Antibacterial Agent, TNP-2092, on Gut Microbiota and Potential Application in the Treatment of Gastrointestinal and Liver Disorders

TNP-2092 is a unique multitargeting drug conjugate with extremely low propensity for development of resistance. The in vitro activity of TNP-2092 against a panel of urease-producing bacteria was similar to that of rifaximin, a locally acting antibiotic approved for the treatment of hepatic encephalopathy, irritable bowel syndrome with diarrhea, and traveler's diarrhea. When given orally, TNP-2092 exhibited low absorption and the majority of compound was recovered in feces as parent. The impact of oral TNP-2092 on gut microbiota was investigated in rats. TNP-2092 was administered to rats by oral gavage for 7 days. Feces samples were collected and analyzed by 16S rRNA sequencing. Although the total amount of bacterial load appeared relatively unchanged before, during, and after treatment, significant changes in the relative abundance of certain gut bacteria at family and genus levels were observed. Some of the changes are known to be associated with improvement of symptoms associated with liver cirrhosis and hepatic encephalopathy. The observed effects of TNP-2092 on gut microbiota in rats were similar to those of rifaximin. In vivo, TNP-2092 demonstrated potent efficacy in a mouse Clostridium difficile infection model, superior to metronidazole and vancomycin, with no relapse observed after treatment. TNP-2092 is currently in clinical development for the treatment of symptoms associated with gastrointestinal and liver disorders.

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.

Salidroside improves high-fat diet-induced non-alcoholic steatohepatitis by regulating the gut microbiota-bile acid-farnesoid X receptor axis

BACKGROUND

Our previous studies found that salidroside can effectively treat non-alcoholic steatohepatitis (NASH). Here, we discuss the mechanism of salidroside in the treatment of NASH with a focus on the gut microbiota-bile acid-farnesoid X receptor axis.

METHODS

A NASH mouse model was created by providing mice with a high-fat diet (HFD) for 14 weeks. Mice were randomly divided into the HFD group, HFD + salidroside treatment group, and HFD + obeticholic acid treatment group (n = 8 in each group) and were intragastrically administered corresponding drugs for 4 weeks. Hematoxylin-eosin staining was performed to evaluate the histopathological changes associated with the various treatments. In addition, liver triglyceride (TG) content, serum alanine aminotransferase (ALT) activity, serum inflammatory factors, gut microbiota diversity, and the bile acid profile were evaluated. Western blotting and RT-PCR were performed to detect the expressions of FXR and fibroblast growth factor 15 (FGF15).

RESULTS

The HFD group displayed obvious signs of hepatic steatosis. The liver TG, serum ALT, and IL-1a, IL-12, MCP-1, KC, MIP-1a, and MIP-1β were significantly higher in the HFD group than the control group (P < 0.01). Intestinal bacteria and bile acid profiles changed significantly in the HFD group (P < 0.05). Further, the expressions of FXR and FGF15 decreased significantly in the HFD group (P < 0.05). After treatment with salidroside, liver steatosis, TG content, and serum inflammatory factors significantly improved and HFD-induced intestinal bacteria, bile acid disorder, and FXR deficiency were significantly alleviated (P < 0.05).

CONCLUSION

Salidroside can improve NASH via the gut microbiota-bile acid-FXR axis.

When the beverage is sweet, how does the liver feel?

Purpose of review

The purpose of this paper is to both review the available data and also highlight the gaps in knowledge, regarding the link between pediatric NASH and different type of sweeteners including caloric sweeteners (CS) and non-caloric sweeteners (NCS).

Recent findings

Studies have demonstrated that patients with NASH generally have had an unhealthy diet, characterized by on overconsumption of carbohydrates especially fructose. Mechanistically, a high-fructose diet reduces hepatic lipid oxidation, increases proinflammatory response, increases intestinal permeability and decreases microbiome diversity. Consumption and availability of NCS has therefore been increasing dramatically. Most NCS are not considered to be metabolized in the body and therefore thought to be safe for consumption. It was reported that pharmacological properties of rebaudioside, a type of NCS, as a potential hepatoprotector are through anti-inflammatory and antifibrotic mechanisms, associated with enhancing glucose-induced insulin secretion and inducing the difference of microbiome diversity.

Summary

Diet is an important factor in the pathogenesis of NAFLD and popular dietary patterns are contributing to the increased replacement of natural sweeteners with NCS. Screening for NAFLD by pediatricians and counseling on the avoidance of sugar-sweetened beverages are recommended. We feel that the various NCS available to the consumer today merit further investigation, and may potentially have hitherto unknown effects on hepatic metabolic function.

Vitamin D and nonalcoholic fatty liver disease

PURPOSE OF REVIEW

Vitamin D deficiency may impact disease progression of nonalcoholic fatty liver disease (NAFLD). The aim of this work was to review recent studies examining either vitamin D status or the effects of supplementation in patients with NAFLD, along with investigating the roles of genetic polymorphisms and the gut microbiome.

RECENT FINDINGS

Six heterogeneous observational studies of vitamin D status, and four randomized controlled intervention trials of vitamin D supplementation in NAFLD were conflicting. All studies were hampered by the challenges of diagnosing NAFLD, were underpowered, and lacked data on clinically important outcomes. The results of three cross-sectional studies, including a Mendelian randomization study, provide limited evidence for a role for genetic modifiers of vitamin D status in NAFLD. Genetic and experimental evidence suggests that vitamin D and the vitamin D receptor (VDR) may influence the gut microbiome in health and disease.

SUMMARY

The evidence relating either lower vitamin D status to the prevalence and severity of NAFLD, or examining vitamin D supplementation in patients with NAFLD is inconclusive. Larger, higher quality trials with relevant endpoints are needed. Further mechanistic studies on the roles of vitamin D and VDR in influencing the gut-liver axis in NAFLD are warranted.

Dual Specificity Phosphatase 12 Regulates Hepatic Lipid Metabolism Through Inhibition of the Lipogenesis and Apoptosis Signal-Regulating Kinase 1 Pathways

Nonalcoholic fatty liver disease (NAFLD) has become the most common cause of chronic liver disease worldwide. Due to the growing economic burden of NAFLD on public health, it has become an emergent target for clinical intervention. DUSP12 is a member of the dual specificity phosphatase (DUSP) family, which plays important roles in brown adipocyte differentiation, microbial infection, and cardiac hypertrophy. However, the role of DUSP12 in NAFLD has yet to be clarified. Here, we reveal that DUSP12 protects against hepatic steatosis and inflammation in L02 cells after palmitic acid/oleic acid treatment. We demonstrate that hepatocyte specific DUSP12-deficient mice exhibit high-fat diet (HFD)-induced and high-fat high-cholesterol diet-induced hyperinsulinemia and liver steatosis and decreased insulin sensitivity. Consistently, DUSP12 overexpression in hepatocyte could reduce HFD-induced hepatic steatosis, insulin resistance, and inflammation. At the molecular level, steatosis in the absence of DUSP12 was characterized by elevated apoptosis signal-regulating kinase 1 (ASK1), which mediates the mitogen-activated protein kinase (MAPK) pathway and hepatic metabolism. DUSP12 physically binds to ASK1, promotes its dephosphorylation, and inhibits its action on ASK1-related proteins, JUN N-terminal kinase, and p38 MAPK in order to inhibit lipogenesis under high-fat conditions. Conclusion: DUSP12 acts as a positive regulator in hepatic steatosis and offers potential therapeutic opportunities for NAFLD.

Association between Helicobacter pylori infection and nonalcoholic fatty liver disease: A systematic review and meta-analysis of observational studies

BACKGROUND

The association between Helicobacter pylori (H. pylori) infection and nonalcoholic fatty liver disease (NAFLD) has been shown in many observational studies, but these conclusions remain controversial. Hence, we performed a meta-analysis to elucidate the association.

METHODS

A comprehensive search was conducted on relevant studies published from inception to December 31, 2018, in PubMed, EMBASE, and Web of Science databases. Odds ratio (OR) with 95% confidence interval (95% CI) were pooled by random-effect model, generic inverse variance method. Subgroup and sensitivity analyses were also done. Publication bias was estimated by the funnel plot, Begg's test, and Egger's test.

RESULTS

Fifteen studies (eleven cross-sectional, two case-control, and two cohort studies) were included in this meta-analysis. The pooled OR of NAFLD in patients with H. pylori infection was 1.19 (95% CI: 1.11-1.29, P < 0.00001) when compared with the patients without H. pylori infection. Similar results were observed when the subgroup analyses were stratified by different geographical locations, study designs, and confounders adjustment. In subgroup analysis stratified by different H. pylori testing methods, the correlation still exists when using UBT, serology, RUT, or SAT, but there was no statistically significant difference when using multiple detection methods (OR = 2.96, 95% CI: 0.37-23.94, P = 0.31). Sensitivity analyses showed that our results were robust. No evidence of substantial publication bias was detected.

CONCLUSIONS

Current evidence indicated that a positive association between H. pylori infection and the risk of NAFLD. Further prospective studies are warranted to strengthen the association and to clarify whether there is a causative link between them.

Epigenetic Markers and Microbiota/Metabolite-Induced Epigenetic Modifications in the Pathogenesis of Obesity, Metabolic Syndrome, Type 2 Diabetes, and Non-alcoholic Fatty Liver Disease

PURPOSE OF REVIEW

The metabolic syndrome is a pathological state in which one of the key components is insulin resistance. A wide spectrum of body compartments is involved in its pathophysiology. Genetic and environmental factors such as diet and physical activity are both related to its etiology. Reversible modulation of gene expression without altering the DNA sequence, known as epigenetic modifications, has been shown to drive this complex metabolic cluster of conditions. Here, we aim to examine some of the recent research of specific epigenetically mediated mechanisms and microbiota-induced epigenetic modifications on the development of adipose tissue and obesity, β-cell dysfunction and diabetes, and hepatocytes and non-alcoholic fatty disease.

RECENT FINDINGS

DNA methylation patterns and histone modifications have been identified in this context; the integrated analysis of genome, epigenome, and transcriptome is likely to expand our knowledge of epigenetics in health and disease. Epigenetic modifications induced by diet-related microbiota or metabolites possibly contribute to the insulin-resistant state. The identification of epigenetic signatures on diabetes and obesity may give us the possibility of developing new interventions, prevention measures, and follow-up strategies.

Integration of microbiology, molecular pathology, and epidemiology: a new paradigm to explore the pathogenesis of microbiome-driven neoplasms

Molecular pathological epidemiology (MPE) is an integrative transdisciplinary field that addresses heterogeneous effects of exogenous and endogenous factors (collectively termed 'exposures'), including microorganisms, on disease occurrence and consequences, utilising molecular pathological signatures of the disease. In parallel with the paradigm of precision medicine, findings from MPE research can provide aetiological insights into tailored strategies of disease prevention and treatment. Due to the availability of molecular pathological tests on tumours, the MPE approach has been utilised predominantly in research on cancers including breast, lung, prostate, and colorectal carcinomas. Mounting evidence indicates that the microbiome (inclusive of viruses, bacteria, fungi, and parasites) plays an important role in a variety of human diseases including neoplasms. An alteration of the microbiome may be not only a cause of neoplasia but also an informative biomarker that indicates or mediates the association of an epidemiological exposure with health conditions and outcomes. To adequately educate and train investigators in this emerging area, we herein propose the integration of microbiology into the MPE model (termed 'microbiology-MPE'), which could improve our understanding of the complex interactions of environment, tumour cells, the immune system, and microbes in the tumour microenvironment during the carcinogenic process. Using this approach, we can examine how lifestyle factors, dietary patterns, medications, environmental exposures, and germline genetics influence cancer development and progression through impacting the microbial communities in the human body. Further integration of other disciplines (e.g. pharmacology, immunology, nutrition) into microbiology-MPE would expand this developing research frontier. With the advent of high-throughput next-generation sequencing technologies, researchers now have increasing access to large-scale metagenomics as well as other omics data (e.g. genomics, epigenomics, proteomics, and metabolomics) in population-based research. The integrative field of microbiology-MPE will open new opportunities for personalised medicine and public health. Copyright © 2019 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Effect of Wakame and Carob Pod Snacks on Non-Alcoholic Fatty Liver Disease

Snacks combining different functional ingredients could represent a useful therapeutic strategy against NAFLD. The present study aimed to analyze the effect of two snack formulations based on carob and wakame flour in the treatment for NAFLD in rats. For this purpose, metabolic syndrome was induced in 50 adult rats by a high-fat high-fructose diet over eight weeks. After this period, rats were fed either normal calorie diets supplemented or not with snack A (1/50 wakame/carob pod) and snack B (1/5 wakame/carob pod) for four additional weeks. After sacrifice, liver composition and serum parameters were analyzed. Different pathways of triacylglycerol metabolism in liver were studied including fatty acid oxidation, fatty acid synthesis, triglyceride assembly and release, fatty acid uptake and glucose uptake. Oxidative stress was also measured. Snack treatment, and mainly B snack, reduced liver triacylglycerol levels by increasing fat oxidation. Moreover, this snack reduced oxidative stress. Therefore, this snack formulation could represent an interesting tool useful for fatty liver treatment.