Beneficial Effects of Lactobacillus plantarum Strains on Non-Alcoholic Fatty Liver Disease in High Fat/High Fructose Diet-Fed Rats

The current findings on the gut-liver axis and the molecular basis of NAFLD/NASH associated with gut microbiome dysbiosis

Recent research has highlighted the complex relationship between gut microbiota, metabolic pathways, and nonalcoholic fatty liver disease (NAFLD) progression. Gut dysbiosis, commonly observed in NAFLD patients, impairs intestinal permeability, leading to the translocation of bacterial products like lipopolysaccharides, short-chain fatty acids, and ethanol to the liver. These microbiome-associated mechanisms contribute to intestinal and hepatic inflammation, potentially advancing NAFLD to NASH. Dietary habits, particularly those rich in saturated fats and fructose, can modify the microbiome composition, leading to dysbiosis and fatty liver development. Metabolomic approaches have identified unique profiles in NASH patients, with specific metabolites like ethanol linked to disease progression. While bariatric surgery has shown promise in preventing NAFLD progression, the role of gut microbiome and metabolites in this improvement remains to be proven. Understanding these microbiome-related pathways may provide new diagnostic and therapeutic targets for NAFLD and NASH. A comprehensive review of current literature was conducted using multiple medical research databases, including PubMed, Scopus, Web of Science, Embase, Cochrane Library, ClinicalTrials.gov, ScienceDirect, Medline, ProQuest, and Google Scholar. The review focused on studies that examine the relationship between gut microbiota composition, metabolic pathways, and NAFLD progression. Key areas of interest included microbial dysbiosis, endotoxin production, and the influence of diet on gut microbiota. The analysis revealed that gut dysbiosis contributes to NAFLD through several mechanisms, diet significantly influences gut microbiota composition, which in turn affects liver function through the gut-liver axis. High-fat diets can lead to dysbiosis, altering microbial metabolic activities and promoting liver inflammation. Specifically, gut microbiota-mediated generation of saturated fatty acids, such as palmitic acid, can activate liver macrophages and increase TNF-α expression, contributing to NASH development. Different dietary components, including cholesterol, fiber, fat, and carbohydrates, can modulate the gut microbiome and influence NAFLD progression. This gut-liver axis plays a crucial role in maintaining immune homeostasis, with the liver responding to gut-derived bacteria by activating innate and adaptive immune responses. Microbial metabolites, such as bile acids, tryptophan catabolites, and branched-chain amino acids, regulate adipose tissue and intestinal homeostasis, contributing to NASH pathogenesis. Additionally, the microbiome of NASH patients shows an elevated capacity for alcohol production, suggesting similarities between alcoholic steatohepatitis and NASH. These findings indicate that targeting the gut microbiota may be a promising approach for NASH treatment and prevention. Recent research highlights the potential of targeting gut microbiota for managing nonalcoholic fatty liver disease (NAFLD). The gut-liver axis plays a crucial role in NAFLD pathophysiology, with dysbiosis contributing to disease progression. Various therapeutic approaches aimed at modulating gut microbiota have shown promise, including probiotics, prebiotics, synbiotics, fecal microbiota transplantation, and dietary interventions. Probiotics have demonstrated efficacy in human randomized controlled trials, while other interventions require further investigation in clinical settings. These microbiota-targeted therapies may improve NAFLD outcomes through multiple mechanisms, such as reducing inflammation and enhancing metabolic function. Although lifestyle modifications remain the primary recommendation for NAFLD management, microbiota-focused interventions offer a promising alternative for patients struggling to achieve weight loss targets.

The effect of adipose-derived mesenchymal stem cells against high fructose diet induced liver dysfunction and dysbiosis

High fructose diet (HFrD) has been approved to be involved in the pathogenesis of insulin resistance. Mesenchymal stem cells have a vital role in the treatment of various diseases including metabolic disturbances. We investigated the effect of Adipose-derived mesenchymal stem cells (ADMSCs) against HFrD-induced metabolic disorders and the molecular mechanisms for this effect. Rats were divided into 3 groups; control, HFrD, and combined HFrD with ADMSCs. We assessed liver functions, gut microbiota activity, oxidative stress, adiponectin, and IL10 levels. Also, we measured SREBP-1, IRS-1 expression using Western blot, and Malat1 expression using rt-PCR. ADMSCs antagonized metabolic abnormalities induced by HFrD in the form of improvement of liver functions and alleviation of oxidative stress. In addition, ADMSCs ameliorated gut microbiota activity besides the elevation of adiponectin and IL10 levels. ADMSCs attenuated insulin resistance through upregulation of IRS1 and downregulation of SREBP-1 and Malat1. ADMSCs can protect against HFrD-induced metabolic hazards.

Role of trans-resveratrol in ameliorating biochemical and molecular alterations in obese rats induced by a high fructose/fat diet

We evaluated the effect of trans-resveratrol (RSV) in ameliorating biochemical and molecular alterations in obese Wister male rats fed on high-fat/high-fructose-fed. Male Wister rats were divided into eight groups and fed with either a standard diet (control), high fructose (HF), high fat (HFAT), or a high- fructose high- fat (HF/HFAT) diet and supplemented with RSV (30 mg/kg/day) for 4 weeks. The food intake, body weight, glycemic parameters, lipid profile, oxidative stress were assessed. SIRT1 gene expression, PGC-1α, cyto-c and GLUT-4 were evaluated by qRT-PCR in adipose tissue of normal and obese rats. The body weight gain, serum fasting glucose, insulin, and HOMA-IR values were significantly higher in the HF and HF/HFAT groups than in the HFAT and control groups. Hyperlipidemia was observed in high calorie diets fed rats compared to control group. The levels of total cholesterol, triglycerides and LDL-c were significantly elevated while HDL- c was significantly decreased in HF & HF/HFAT groups compared to HFAT group. The levels of serum malondialdhyde (MDA) and superoxide dismutase (SOD) activity in adipose tissue were elevated in all groups compared to control group, particularly in the groups that were kept on a high fructose diets (HF, HF/HFAT). SIRT-1, PGC-1α, Cyto-c, and GLUT-4 genes levels were significantly down regulated in HF, HFAT & HF/HFAT groups compared to control group. Supplementation of T-RSV restored the alteration in carbohydrates-lipid metabolism as well as oxidative stress and upregulation of SIRT-1, PGC-1α, Cyto-c, and GLUT-4 genes. RSV is a promising treatment in the management of pathologic consequences of obesity from high-calorie diet consumption via molecular alteration of target genes.

Comparative effects of viable Lactobacillus rhamnosus GG and its heat-inactivated paraprobiotic in the prevention of high-fat high-fructose diet-induced non-alcoholic fatty liver disease in rats

Nonalcoholic fatty liver disease (NAFLD) is one of the most prevalent chronic liver alterations worldwide, being gut microbiota dysbiosis one of the contributing factors to its development. The aim of this research is to compare the potential effects of a viable probiotic (Lactobacillus rhamnosus GG) with those exerted by its heat-inactivated paraprobiotic counterpart in a dietary rodent model of NAFLD. The probiotic administration effectively prevented the hepatic lipid accumulation induced by a high-fat high-fructose diet feeding, as demonstrated by chemical (lower TG content) and histological (lower steatosis grade and lobular inflammation) analyses. This effect was mainly mediated by the downregulation of lipid uptake (FATP2 protein expression) and upregulating liver TG release to bloodstream (MTTP activity) in rats receiving the probiotic. By contrast, the effect of the paraprobiotic preventing diet-induced liver lipid accumulation was milder, and mainly derived from the downregulation of hepatic de novo lipogenesis (SREBP-1c protein expression and FAS activity) and TG assembly (DGAT2 and AQP9 protein expression). The obtained results demonstrate that under these experimental conditions, the effects induced by the administration of viable L. rhamnosus GG preventing liver lipid accumulation in rats fed a diet rich in saturated fat and fructose differ from those induced by its heat-inactivated paraprobiotic counterpart.

Dietary Influences on Gut Microbiota and Their Role in Metabolic Dysfunction-Associated Steatotic Liver Disease (MASLD)

Metabolic dysfunction-associated steatotic liver disease (MASLD) is a major contributor to liver-related morbidity, cardiovascular disease, and metabolic complications. Lifestyle interventions, including diet and exercise, are first line in treating MASLD. Dietary approaches such as the low-glycemic-index Mediterranean diet, the ketogenic diet, intermittent fasting, and high fiber diets have demonstrated potential in addressing the metabolic dysfunction underlying this condition. The development and progression of MASLD are closely associated with taxonomic shifts in gut microbial communities, a relationship well-documented in the literature. Given the importance of diet as a primary treatment for MASLD, it is important to understand how gut microbiota and their metabolic byproducts mediate favorable outcomes induced by healthy dietary patterns. Conversely, microbiota changes conferred by unhealthy dietary patterns such as the Western diet may induce dysbiosis and influence steatotic liver disease through promoting hepatic inflammation, up-regulating lipogenesis, dysregulating bile acid metabolism, increasing insulin resistance, and causing oxidative damage in hepatocytes. Although emerging evidence has identified links between diet, microbiota, and development of MASLD, significant gaps remain in understanding specific microbial roles, metabolite pathways, host interactions, and causal relationships. Therefore, this review aims to provide mechanistic insights into the role of microbiota-mediated processes through the analysis of both healthy and unhealthy dietary patterns and their contribution to MASLD pathophysiology. By better elucidating the interplay between dietary nutrients, microbiota-mediated processes, and the onset and progression of steatotic liver disease, this work aims to identify new opportunities for targeted dietary interventions to treat MASLD efficiently.

Effects of Probiotics on Liver Diseases: Current In Vitro and In Vivo Studies

Various types of liver or hepatic diseases cause the death of about 2 million people worldwide every year, of which 1 million die from the complications of cirrhosis and another million from hepatocellular carcinoma and viral hepatitis. Currently, the second most common solid organ transplant is the liver, and the current rate represents less than 10% of global transplant requests. Hence, finding new approaches to treat and prevent liver diseases is essential. In liver diseases, the interaction between the liver, gut, and immune system is crucial, and probiotics positively affect the human microbiota. Probiotics are a non-toxic and biosafe alternative to synthetic chemical compounds. Health promotion by lowering cholesterol levels, stimulating host immunity, the natural gut microbiota, and other functions are some of the activities of probiotics, and their metabolites, including bacteriocins, can exert antimicrobial effects against a broad range of pathogenic bacteria. The present review discusses the available data on the results of preclinical and clinical studies on the effects of probiotic administration on different types of liver diseases.

Dietary supplementation of probiotic Lactobacillus modulates metabolic dysfunction-associated steatotic liver disease and intestinal barrier integrity in obesity-induced mice

The impact of Lacticaseibacillus paracasei NWAFU334 and Limosilactobacillus fermentum NWAFU0035 on the amelioration of liver function, oxidative stress reduction, and lipid metabolism modulation in mice subjected to an obesity-inducing high-fat diet (HFD) model was investigated. L. paracasei NWAFU334 and L. fermentum NWAFU0035 supplementations over 12 weeks have been shown to have numerous beneficial effects in mice with induced obesity. These effects comprise the restoration of liver function and the reduction of oxidative stress within the liver. Furthermore, the supplementation led to a decreased content of fat accumulation in the liver, mitigation of the expression of inflammatory cytokines in the liver and colon, and a decrease in the expression levels of tight-junction proteins, for example, claudin-1, PPARγ, occludin, and ZO-1. Additionally, a notable improvement in the colonic expression proteins, including IL-6, TNF-α, IL-1β, Muc-2, Muc-3, Zo-1, claudin-1, and occludin. These proposed strains considerably decreased proinflammatory cytokines and influenced the regulation of lipid metabolism in the liver. These findings indicate that the potential mechanisms, primarily the impact of L. paracasei NWAFU334 and L. fermentum NWAFU0035 on obesity-induced liver function in mice, involve two regulated pathways: downregulation of lipogenesis and upregulation of gene expression related to fatty acid oxidation and lipolysis. In other words, these probiotic bacterial strains might be beneficial in reducing fat production and increasing fat breakdown in the liver. They may serve as effective therapeutic supplements for alleviating abnormalities induced by an HFD.

Impact of Lactobacillaceae supplementation on the multi-organ axis during MASLD

The gut-liver axis plays a pivotal role in maintaining body homeostasis. Disruption of the gut-liver axis is linked to a multitude of diseases, including metabolic dysfunction-associated steatotic liver disease (MASLD). Probiotic strains from the Lactobacillaceae family are commonly used to mitigate experimental MASLD. Over the years, numerous studies have demonstrated the efficacy of these probiotics, often focusing on the outcome of liver disease. This review aims to further understand MASLD as a systemic metabolic dysfunction and to highlight the effects of probiotics on multi-organ axis, including organs such as the gastrointestinal tract, pancreas, muscle, adipose tissue, and the immune system. We specifically discuss evidence on how supplementation with Lactobacillaceae strains may alleviate MASLD by not only restoring liver health but also by modulating the physiology of other organ systems.

Probiotics and Non-Alcoholic Fatty Liver Disease: Unveiling the Mechanisms of Lactobacillus plantarum and Bifidobacterium bifidum in Modulating Lipid Metabolism, Inflammation, and Intestinal Barrier Integrity

In recent years, the prevalence of non-alcoholic fatty liver disease (NAFLD) has risen annually, yet due to the intricacies of its pathogenesis and therapeutic challenges, there remains no definitive medication for this condition. This review explores the intricate relationship between the intestinal microbiome and the pathogenesis of NAFLD, emphasizing the substantial roles played by Lactobacillus plantarum and Bifidobacterium bifidum. These probiotics manipulate lipid synthesis genes and phosphorylated proteins through pathways such as the AMPK/Nrf2, LPS-TLR4-NF-κB, AMPKα/PGC-1α, SREBP-1/FAS, and SREBP-1/ACC signaling pathways to reduce hepatic lipid accumulation and oxidative stress, key components of NAFLD progression. By modifying the intestinal microbial composition and abundance, they combat the overgrowth of harmful bacteria, alleviating the inflammatory response precipitated by dysbiosis and bolstering the intestinal mucosal barrier. Furthermore, they participate in cellular immune regulation, including CD4+ T cells and Treg cells, to suppress systemic inflammation. L. plantarum and B. bifidum also modulate lipid metabolism and immune reactions by adjusting gut metabolites, including propionic and butyric acids, which inhibit liver inflammation and fat deposition. The capacity of probiotics to modulate lipid metabolism, immune responses, and gut microbiota presents an innovative therapeutic strategy. With a global increase in NAFLD prevalence, these insights propose a promising natural method to decelerate disease progression, avert liver damage, and tackle associated metabolic issues, significantly advancing microbiome-focused treatments for NAFLD.

Single and Mixed Strains of Probiotics Reduced Hepatic Fat Accumulation and Inflammation and Altered Gut Microbiome in a Nonalcoholic Steatohepatitis Rat Model

As gut dysbiosis has been implicated in the pathogenesis of nonalcoholic steatohepatitis (NASH), probiotic supplementation might be a potential treatment for this condition. The aim of this study was to evaluate the effects of single- and mixed-strain probiotics on the severity of NASH induced by a high-fat, high-fructose (HFHF) diet and their mechanisms of action. Male Sprague-Dawley rats were divided into four groups (n = 7 per group): control group, NASH group, NASH + single-strain group, and NASH + mixed-strain group. In the single-strain and mixed-strain groups, rats received Lactobacillus plantarum B7 and Lactobacillus rhamnosus L34 + Lactobacillus paracasei B13 by oral gavage once daily, respectively. The duration of the study was 6 weeks. Liver tissue was used for histopathology, hepatic fat content was assessed by Oil Red O staining and hepatic free fatty acid (FFA), and hepatic TLR4 and CD14 expression were assessed by immunohistochemistry. Fresh feces was collected for gut microbiota analysis. Liver histology revealed a higher degree of fat accumulation, hepatocyte ballooning, and lobular inflammation in the NASH group, which improved in probiotics-treated groups. The amounts of hepatic fat droplets and hepatic FFA levels were more pronounced in the NASH group than in the control and treatment groups. Serum TNF- α levels were significantly higher in the NASH group than in control and probiotic groups. The expression of CD14 and TLR4 increased in the NASH group as compared with the control and probiotics-treated groups. Alpha diversity was reduced in the NASH group, but increased in both treatment groups. The relative abundance of Lactobacillus significantly decreased in the NASH group, but increased in both treatment groups. The relative abundance of Akkermansia significantly increased in the NASH group, but decreased in both treatment groups. In conclusion, both single-strain and mixed-strain probiotics could improve NASH histology by suppressing inflammatory responses in the liver, with this improvement potentially being associated with changes in the gut microbiota.

Silymarin decreases liver stiffness associated with gut microbiota in patients with metabolic dysfunction-associated steatotic liver disease: a randomized, double-blind, placebo-controlled trial

BACKGROUND

Despite centuries of traditional use of silymarin for hepatoprotection, current randomized controlled trial (RCT) studies on the effectiveness of silymarin in managing metabolic dysfunction-associated steatotic liver disease (MASLD) are limited and inconclusive, particularly when it is administered alone. The low bioavailability of silymarin highlights the possible influence of gut microbiota on the effectiveness of silymarin; however, no human studies have investigated this aspect.

OBJECTIVE

To determine the potential efficacy of silymarin in improving MASLD indicators and to investigate the underlying mechanisms related to gut microbiota.

METHOD

In this 24-week randomized, double-blind, placebo-controlled trial, 83 patients with MASLD were randomized to either placebo (n = 41) or silymarin (103.2 mg/d, n = 42). At 0, 12, and 24 weeks, liver stiffness and hepatic steatosis were assessed using FibroScan, and blood samples were gathered for biochemical detection, while faecal samples were collected at 0 and 24 weeks for 16S rRNA sequencing.

RESULTS

Silymarin supplementation significantly reduced liver stiffness (LSM, -0.21 ± 0.17 vs. 0.41 ± 0.17, P = 0.015) and serum levels of γ-glutamyl transpeptidase (GGT, -8.21 ± 3.01 vs. 1.23 ± 3.16, P = 0.042) and ApoB (-0.02 ± 0.03 vs. 0.07 ± 0.03, P = 0.023) but had no significant effect on the controlled attenuation parameter (CAP), other biochemical indicators (aminotransferases, total bilirubin, glucose and lipid parameters, hsCRP, SOD, and UA), physical measurements (DBP, SBP, BMI, WHR, BF%, and BMR), or APRI and FIB-4 indices. Gut microbiota analysis revealed increased species diversity and enrichment of Oscillospiraceae in the silymarin group.

CONCLUSION

These findings suggest that silymarin supplementation could improve liver stiffness in MASLD patients, possibly by modulating the gut microbiota.

TRIAL REGISTRATION

The trial was registered at the Chinese Clinical Trial Registry (ChiCTR2200059043).

Lactiplantibacillus plantarum ZDY2013 Inhibits the Development of Non-Alcoholic Fatty Liver Disease by Regulating the Intestinal Microbiota and Modulating the PI3K/Akt Pathway

Non-alcoholic fatty liver disease (NAFLD) is a common chronic hepatic condition whose impact on human health is increasingly significant. The imbalance of the gut microbiome, linked to insulin resistance, heightened intestinal permeability, and pro-inflammatory reactions, may be the linchpin in the development of NAFLD. In our research, the impact of Lactiplantibacillus plantarum ZDY2013 administration for 12 weeks on gut microbiota dysbiosis induced by a high-fat, high-fructose, high-cholesterol (FHHC) diet in male C57BL/6n mice was investigated. Research results presented that the intervention of L. plantarum ZDY2013 in mice fed with the FHHC diet could restore their liver function and regulate oxidative stress. Compared to mice in the model group, the intervention of L. plantarum ZDY2013 significantly regulated the gut microbiota, inhibited the LPS/NF-κB pathway, and led to a lower level of colonic inflammation in the mice administered with L. plantarum ZDY2013. It also improved insulin resistance to regulate the PI3K/Akt pathway and lipid metabolism, thereby resulting in reduced fat accumulation in the liver. The above results suggest that the intervention of L. plantarum ZDY2013 can hinder the progression of diet-induced NAFLD by reducing inflammation to regulate the PI3K/Akt pathway and regulating gut microbiota disturbance.

Bifidobacterium lactis Probio‐M8 prevents nonalcoholic fatty liver disease in high‐fat diet‐fed rats: The potential role in modulating gut microbiota

Nonalcoholic fatty liver disease (NAFLD) is a major global health problem with few therapeutic options available so far. Accumulating evidence suggests that probiotics have beneficial effects on NAFLD by modulating gut microbiota. Bifidobacterium lactis Probio‐M8 (M8) is a new probiotic strain isolated from human breast milk. The aim of this study was to investigate whether M8 could protect against NAFLD in rats fed a high‐fat diet by modulating gut microbiota. In this study, rats were randomly distributed into four groups: normal diet (ND) group, normal diet plus M8 (ND+M8) group, high‐fat diet (HFD) group, and high‐fat diet plus M8 (HFD+M8) group. Ten weeks later, hepatic morphological changes and biochemical indicators were measured. 16S rDNA sequencing was applied to analyze the gut microbiota alterations. Our results showed that M8 administration effectively improved hepatic steatosis and liver damage in high‐fat diet‐fed rats. 16S rDNA analysis of gut microbiota indicated that M8 could modulate the gut microbiota composition, especially increasing Bifidobacterium and decreasing Bilophila, Lachnoclostridium, GCA‐900066225, and Phascolarctobacterium in high‐fat diet‐fed rats. In conclusion, our findings demonstrated that M8 could protect against NAFLD in rats fed a high‐fat diet, which may be attributed to the modulation of gut microbiota.

Mechanism of Action and Related Natural Regulators of Nrf2 in Nonalcoholic Fatty Liver Disease

With the acceleration of people's pace of life, non-alcoholic fatty liver disease (NAFLD) has become the most common chronic liver disease in the world, which greatly threatens people's health and safety. Therefore, there is still an urgent need for higher-quality research and treatment in this area. Nuclear factor Red-2-related factor 2 (Nrf2), as a key transcription factor in the regulation of oxidative stress, plays an important role in inducing the body's antioxidant response. Although there are no approved drugs targeting Nrf2 to treat NAFLD so far, it is still of great significance to target Nrf2 to alleviate NAFLD. In recent years, studies have reported that many natural products treat NAFLD by acting on Nrf2 or Nrf2 pathways. This article reviews the role of Nrf2 in the pathogenesis of NAFLD and summarizes the currently reported natural products targeting Nrf2 or Nrf2 pathway for the treatment of NAFLD, which provides new ideas for the development of new NAFLD-related drugs.

Lactobacillus plantarum ameliorates NASH-related inflammation by upregulating L-arginine production

Lactobacillus is a probiotic with therapeutic potential for several diseases, including liver disease. However, the therapeutic effect of L. plantarum against nonalcoholic steatohepatitis (NASH) and its underlying mechanisms remain unelucidated. Therefore, we delineated the L. plantarum-mediated NASH regulation in a mouse model to understand its therapeutic effect. We used a choline-deficient high-fat diet (CD-HFD)-induced murine model that recapitulated the critical features of human metabolic syndrome and investigated the effect of L. plantarum on NASH pathogenesis using transcriptomic, metagenomic, and immunohistochemistry analyses. Validation experiments were performed using liver organoids and a murine model fed a methionine-choline-deficient (MCD) diet. L. plantarum treatment in mice significantly decreased liver inflammation and improved metabolic phenotypes, such as insulin tolerance and the hepatic lipid content, compared with those in the vehicle group. RNA-sequencing analysis revealed that L. plantarum treatment significantly downregulated inflammation-related pathways. Shotgun metagenomic analysis revealed that L-arginine biosynthesis-related microbial genes were significantly upregulated in the L. plantarum group. We also confirmed the elevated arginine levels in the serum of the L. plantarum group. We further used liver organoids and mice fed an MCD diet to demonstrate that L-arginine alone was sufficient to alleviate liver inflammation. Our data revealed a novel and counterintuitive therapeutic effect of L. plantarum on alleviating NASH-related liver inflammation by increasing circulating L-arginine.

The effect of heat-killed Lactobacillus brevis SBL88 on improving selective hepatic insulin resistance in non-alcoholic fatty liver disease mice without altering the gut microbiota

BACKGROUND AND AIM

There have been several reports that some probiotics improve non-alcoholic fatty liver disease (NAFLD); however, many studies have involved cocktail therapies. We evaluated whether heat-killed Lactobacillus brevis SBL88 (L. brevis SBL88) monotherapy improves the clinical features of NAFLD.

METHODS

The NAFLD model was induced in mice fed a high-fat diet (HFD) (HFD mice) or HFD + 1% heat-killed L. brevis SBL88 (SBL mice) for 16 weeks. Histopathological liver findings were analyzed. To evaluate the gut microbiota, a modified terminal restriction fragment length polymorphism analysis of the feces was performed. RNA sequencing in the liver was performed with Ion Proton™. To investigate the direct effects of heat-killed L. brevis SBL88, an in vitro study was performed.

RESULTS

Histopathological findings revealed that fat droplets in the liver were significantly reduced in SBL mice; however, terminal restriction fragment length polymorphism did not show alterations in the gut microbiota between HFD mice and SBL mice. RNA sequencing and pathway analysis revealed that the regulation of lipid and insulin metabolism was affected. The mRNA expression of insulin receptor substrate 2 (IRS-2) was significantly higher in SBL mice, whereas the expression of IRS-1 was not significantly different. Phospho-IRS-2 expression was also significantly increased in SBL mice. In addition, an in vitro study revealed significant alterations in IRS-2 and forkhead box protein O1 expression levels.

CONCLUSION

SBL mice exhibited partially improved selective hepatic insulin resistance. Our data suggest that heat-killed L. brevis SBL88 could attenuate the clinical features of NAFLD that are not mediated by alterations in the gut microbiota.

Supplementation of Lactobacillus plantarum ATCC14917 mitigates non-alcoholic fatty liver disease in high-fat-diet-fed rats

Atherosclerosis and non-alcoholic fatty liver disease (NAFLD) have been increasing at an alarming rate worldwide. Many clinical studies have underlined the link between NAFLD and atherosclerosis. Our previous experiments have discovered that Lactobacillus (L.) plantarum ATCC14917 supplementation could decrease the progression of atherosclerotic lesion formation. In this study, we aimed to investigate the role of supplementation of L. plantarum ATCC14917 mitigates liver injury in rats fed with a high-fat diet (HFD, 45% kcal from fat). A total of 32 rats were randomly divided into four groups, including two intervention groups, who fed with HFD and administering either 1 × 10⁷ or 1 × 10⁹ colony forming units (CFU) of L. plantarum ATCC14917, the normal control group, and the HFD control group. The results showed that supplementation with low-dose and high-dose of L. plantarum ATCC14917 for 8 weeks could alleviate the body weight gain (p < 0.05), hepatic steatosis, and serum lipid metabolism (p < 0.05) in HFD-fed rats. Moreover, supplementation of L. plantarum ATCC 14917 decreased total cholesterol (TC), triglyceride (TG), alanine aminotransferase (ALT), and aspartate aminotransferase (AST) levels (p < 0.05) in serum, and improved HFD-associated inflammation (p < 0.05). Furthermore, cecal contents were analyzed by high-throughput 16S ribosomal RNA sequencing. The results indicated that supplementation of L. plantarum ATCC 14917 could ameliorate HFD-induced gut dysbiosis. In summary, our findings suggest that supplementation of L. plantarum ATCC 14917 could mitigate NAFLD in rats, suggesting it may be considered as a probiotic agent for preventing HFD-induced obesity.

Gut Microbiome in the Progression of NAFLD, NASH and Cirrhosis, and Its Connection with Biotics: A Bibliometric Study Using Dimensions Scientific Research Database

There is growing evidence that gut microbiota dysbiosis is linked to the etiopathogenesis of nonalcoholic fatty liver disease (NAFLD), from the initial stage of disease until the progressive stage of nonalcoholic steatohepatitis (NASH) and the final stage of cirrhosis. Conversely, probiotics, prebiotics, and synbiotics have shown promise in restoring dysbiosis and lowering clinical indicators of disease in a number of both preclinical and clinical studies. Additionally, postbiotics and parabiotics have recently garnered some attention. The purpose of this bibliometric analysis is to assess recent publishing trends concerning the role of the gut microbiome in the progression of NAFLD, NASH and cirrhosis and its connection with biotics. The free access version of the Dimensions scientific research database was used to find publications in this field from 2002 to 2022. VOSviewer and Dimensions' integrated tools were used to analyze current research trends. Research into the following topics is expected to emerge in this field: (1) evaluation of risk factors which are correlated with the progression of NAFLD, such as obesity and metabolic syndrome; (2) pathogenic mechanisms, such as liver inflammation through toll-like receptors activation, or alteration of short-chain fatty acids metabolisms, which contribute to NAFLD development and its progression in more severe forms, such as cirrhosis; (3) therapy for cirrhosis through dysbiosis reduction, and research on hepatic encephalopathy a common consequence of cirrhosis; (4) evaluation of diversity, and composition of gut microbiome under NAFLD, and as it varies under NASH and cirrhosis by rRNA gene sequencing, a tool which can also be used for the development of new probiotics and explore into the impact of biotics on the gut microbiome; (5) treatments to reduce dysbiosis with new probiotics, such as Akkermansia, or with fecal microbiome transplantation.

Ampicillin exacerbates acetaminophen-induced acute liver injury by inducing intestinal microbiota imbalance and butyrate reduction

BACKGROUND AND AIMS

Antibiotics (ATBx) and acetaminophen (APAP) are widely used worldwide. APAP is the most common cause of acute liver injury (ALI) and might be used in combination with ATBx in clinics. However, the impact of ATBx on APAP-induced ALI has rarely been studied.

METHODS

First, we compared the effects of seven ATBx on APAP-induced ALI. Then, we analysed faecal, serum and liver samples to investigate the impact of the gut microbiota on this process. Finally, we assessed the role of short-chain fatty acids in this process.

RESULTS

In this work, we found that the ALI was significantly aggravated in the mice treated with ampicillin (Amp) instead of other ATBx. Amp exposure reduced the diversity and altered the composition of gut microbiota. The altered gut microbiota aggravated APAP-induced ALF, which was proven by faecal microbiota transplantation from ATBx-treated mice. Metagenomic analysis showed a significantly decreased Lactobacillus abundance in Amp-treated mice. Gavage with Lactobacillus, especially Lactobacillus rhamnosus, significantly reversed the severer ALF induced by APAP and Amp. Moreover, Lactobacillus supplementation increased butyrate-producing clostridia and lowered butyrate levels in Amp-treated mice. In accordance, butyrate supplementation could also alleviate Amp-aggravated ALI. In addition, inhibition of nuclear factor erythroid 2-related factor 2 counteracted the protective effect of butyrate on aggravated ALI induced by Amp and APAP.

CONCLUSION

Together, this study revealed a potential health impact of Amp that may exacerbate liver damage when co-exposed to excess APAP.

Current, emerging, and potential therapies for non-alcoholic steatohepatitis

Non-alcoholic fatty liver disease (NAFLD) has been identified as the most common chronic liver disease worldwide, with a growing incidence. NAFLD is considered the hepatic manifestation of a metabolic syndrome that emerges from multiple factors (e.g., oxidative stress, metabolic disorders, endoplasmic reticulum stress, cell death, and inflammation). Non-alcoholic steatohepatitis (NASH), an advanced form of NAFLD, has been reported to be a leading cause of cirrhosis and hepatic carcinoma, and it is progressing rapidly. Since there is no approved pharmacotherapy for NASH, a considerable number of therapeutic targets have emerged with the deepening of the research on NASH pathogenesis. In this study, the therapeutic potential and properties of regulating metabolism, the gut microbiome, antioxidant, microRNA, inhibiting apoptosis, targeting ferroptosis, and stem cell-based therapy in NASH are reviewed and evaluated. Since the single-drug treatment of NASH is affected by individual heterogeneous responses and side effects, it is imperative to precisely carry out targeted therapy with low toxicity. Lastly, targeted therapeutic agent delivery based on exosomes is proposed in this study, such that drugs with different mechanisms can be incorporated to generate high-efficiency and low-toxicity individualized medicine.

Beneficial Effects of Viable and Heat-Inactivated Lactobacillus rhamnosus GG Administration on Oxidative Stress and Inflammation in Diet-Induced NAFLD in Rats

Oxidative stress and inflammation are well-known triggers of NAFLD onset and progression. The aim of this study is to compare the potential benefits of a viable probiotic (Lactobacillus rhamnosus GG) and its parabiotic (heat-inactivated) on oxidative stress, inflammation, DNA damage and cell death pathways in the liver of rats featuring diet-induced NAFLD. The consumption of the steatotic diet led to increased final body and liver weights, higher hepatic triacylglycerol content, altered serum transaminase levels and enhanced oxidative and inflammatory status. Administration of the probiotic and the parabiotic partially prevented the body weight increase induced by the steatotic diet, whereas the probiotic caused more effective decreasing hepatic triglyceride content. Sharp but nonstatistically significant decreases in serum transaminase levels were also observed for both treatments. The reduction in antioxidant enzyme activities found in the nontreated animals fed the steatotic diet was partially prevented by both treatments (GPx activity). Similarly, the reductions in nonenzymatic antioxidant protection (GSH content) and total antioxidant capacity (ORAC) found in the nontreated rats were restored by the administration of both treatments. These results show that both viable and heat-inactivated Lactobacillus rhamnosus GG administration partially prevent steatotic diet-induced liver oxidative stress and inflammation induced in rats.

The Effects of Probiotics on Small Intestinal Microbiota Composition, Inflammatory Cytokines and Intestinal Permeability in Patients with Non-Alcoholic Fatty Liver Disease

The prevalence of non-alcoholic fatty liver disease (NAFLD) has soared globally. As our understanding of the disease grows, the role of the gut-liver axis (GLA) in NAFLD pathophysiology becomes more apparent. Hence, we focused mainly on the small intestinal area to explore the role of GLA. We looked at how multi-strain probiotics (MCP^® BCMC^® strains) containing six different Lactobacillus and Bifidobacterium species affected the small intestinal gut microbiota, inflammatory cytokines, and permeability in NAFLD patients. After six months of supplementation, biochemical blood analysis did not show any discernible alterations in either group. Five predominant phyla known as Actinobacteria, Proteobacteria, Firmicutes, Bacteroidota and Fusobacteria were found in NAFLD patients. The probiotics group demonstrated a significant cluster formation of microbiota composition through beta-diversity analysis (p < 0.05). This group significantly reduced three unclassifiable species: unclassified_Proteobacteria, unclassified_Streptococcus, and unclassified_Stenotrophomonas. In contrast, the placebo group showed a significant increase in Prevotella_melaninogenica and Rothia_mucilaginosa, which were classified as pathogens. Real-time quantitative PCR analysis of small intestinal mucosal inflammatory cytokines revealed a significant decrease in IFN-γ (-7.9 ± 0.44, p < 0.0001) and TNF-α (-0.96 ± 0.25, p < 0.0033) in the probiotics group but an increase in IL-6 (12.79 ± 2.24, p < 0.0001). In terms of small intestinal permeability analysis, the probiotics group, unfortunately, did not show any positive changes through ELISA analysis. Both probiotics and placebo groups exhibited a significant increase in the level of circulating zonulin (probiotics: 107.6 ng/mL ± 124.7, p = 0.005 vs. placebo: 106.9 ng/mL ± 101.3, p = 0.0002) and a significant decrease in circulating zonula occluden-1 (ZO-1) (probiotics: -34.51 ng/mL ± 18.38, p < 0.0001 vs. placebo: -33.34 ng/mL ± 16.62, p = 0.0001). The consumption of Lactobacillus and Bifidobacterium suggested the presence of a well-balanced gut microbiota composition. Probiotic supplementation improves dysbiosis in NAFLD patients. This eventually stabilised the expression of inflammatory cytokines and mucosal immune function. To summarise, more research on probiotic supplementation as a supplement to a healthy diet and lifestyle is required to address NAFLD and its underlying causes.

Intestinal dysbiosis mediates cognitive impairment via the intestine and brain NLRP3 inflammasome activation in chronic sleep deprivation

Growing evidence suggests the involvement of the microbiota-gut-brain axis in cognitive impairment induced by sleep deprivation (SD), however how the microbiota-gut-brain axis work remains elusive. Here, we discovered that chronic SD induced intestinal dysbiosis, activated NLRP3 inflammasome in the colon and brain, destructed intestinal/blood-brain barrier, and impaired cognitive function in mice. Transplantation of "SD microbiota" could almost mimic the pathological and behavioral changes caused by chronic SD. Furthermore, all the behavioral and pathological abnormalities were practically reversed in chronic sleep-deprived NLRP3^-/- mice. Regional knockdown NLRP3 expression in the gut and hippocampus, respectively. We observed that down-regulation of NLRP3 in the hippocampus inhibited neuroinflammation, and ameliorated synaptic dysfunction and cognitive impairment induced by chronic SD. More intriguingly, the down-regulation of NLRP3 in the gut protected the intestinal barrier, attenuated the levels of peripheral inflammatory factors, down-regulated the expression of NLRP3 in the brain, and improved cognitive function in chronic SD mice. Our results identified gut microbiota as a driver in chronic SD and highlighted the NLRP3 inflammasome as a key regulator within the microbiota-gut-brain axis.

Lactiplantibacillus plantarum DSM20174 Attenuates the Progression of Non-Alcoholic Fatty Liver Disease by Modulating Gut Microbiota, Improving Metabolic Risk Factors, and Attenuating Adipose Inflammation

Non-alcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease, reaching epidemic proportions worldwide. Targeting the gut-adipose tissue-liver axis by modulating the gut microbiota can be a promising therapeutic approach in NAFLD. Lactiplantibacillus plantarum, a potent lactic-acid-producing bacterium, has been shown to attenuate NAFLD. However, to our knowledge, the possible effect of the Lactiplantibacillus plantarum strain DSM20174 (L.p. DSM20174) on the gut-adipose tissue axis, diminishing inflammatory mediators as fuel for NAFLD progression, is still unknown. Using a NAFLD mouse model fed a high-fat, high-fructose (HFHF) diet for 10 weeks, we show that L.p DSM20174 supplementation of HFHF mice prevented weight gain, improved glucose and lipid homeostasis, and reduced white adipose inflammation and NAFLD progression. Furthermore, 16S rRNA gene sequencing of the faecal microbiota suggested that treatment of HFHF-fed mice with L.p DSM20174 changed the diversity and altered specific bacterial taxa at the levels of family, genus, and species in the gut microbiota. In conclusion, the beneficial effects of L.p DSM20174 in preventing fatty liver progression may be related to modulations in the composition and potential function of gut microbiota associated with lower metabolic risk factors and a reduced M1-like/M2-like ratio of macrophages and proinflammatory cytokine expression in white adipose tissue and liver.

Lactobacillus-fermented yogurt exerts hypoglycemic, hypocholesterolemic, and anti-inflammatory activities in STZ-induced diabetic Wistar rats

Hyperglycemia is a symptom of type 2 diabetes mellitus, a chronic metabolic disease characterized by elevated blood glucose concentrations. Antidiabetic drugs are common treatments for this metabolic disorder; however, they may have unpleasant side effects. This study hypothesized that probiotic fermented products could preserve nutritional value, maintain metabolic homeostasis, and attenuate the inflammatory response associated with diabetes while reducing side effects. Lactobacillus plantarum KU985438 and Lactobacillus rhamnosus KU985439 showed the lowest alfa-amylase enzyme (α-amylase) activity among 8 lactobacilli tested. These 2 strains were used to develop functional fermented milk products, and their antidiabetic efficacy was tested in induced diabetic Wistar rats. The treatment of diabetic rats with L. plantarum KU985438 or L. rhamnosus KU985439 fermented yogurt resulted in a considerable reduction in blood glucose concentrations (136.79% and 145.17%, respectively) and α-amylase concentrations (56.84% and 56.84%, respectively) compared with conventional treatments. Diabetes relief began after 4 days of yogurt consumption compared with drug-based treatment. Significant improvements in both liver and kidney enzyme concentrations were also observed, in addition to a significant increase in high-density lipoprotein cholesterol concentrations and improved lipid profiles. Inhibition in nuclear factor κB and an increase in Bcl-2 concentrations were also detected. Histopathological examination of both hepatic and pancreatic cells revealed the positive effects of the studied treatment compared with standard treatment. Therefore, the selected Lactobacilli, which has hypoglycemic potential, could be used to produce functional nutraceutical antidiabetic supplements.

Probiotics suppress nonalcoholic steatohepatitis and carcinogenesis progression in hepatocyte-specific PTEN knockout mice

Nonalcoholic fatty liver disease (NAFLD), a hepatic characteristic of metabolic syndrome, received significant attention in clinical settings. The multiple-hit theory is one of the proposed mechanisms of NAFLD, and gut dysbiosis is considered a hit. Thus, controlling gut microbiota is a potential target in the management of NAFLD, and probiotics can be used as a treatment agent for NAFLD. The current study aimed to investigate the efficacy of probiotics against nonalcoholic steatohepatitis in a hepatocyte-specific PTEN knockout mouse model that mimics the characteristics of human NAFLD. Probiotics were administered to male knockout mice for 8 or 40 weeks. Next, we assessed hepatic inflammation, fibrosis, carcinogenesis, and oxidative stress. Probiotics were found to reduce serum transaminase levels, NAFLD activity score, and the gene expression of pro-inflammatory cytokines. In addition, they decreased liver fibrosis grade, which was examined via Sirius red staining, gene expression of fibrotic markers, and hydroxyproline. Furthermore, probiotics suppressed the number of liver tumors, particular in HCC. Probiotics reduced oxidative stresses, including glutathione levels, and anti-oxidative stress marker, which may be an underlying mechanism for their beneficial effects. In conclusion, probiotics treatment had beneficial effects against NAFLD and carcinogenesis in hepatocyte-specific PTEN knockout mice.

Age-Related NAFLD: The Use of Probiotics as a Supportive Therapeutic Intervention

Human aging, a natural process characterized by structural and physiological changes, leads to alterations of homeostatic mechanisms, decline of biological functions, and subsequently, the organism becomes vulnerable to external stress or damage. In fact, the elderly population is prone to develop diseases due to deterioration of physiological and biological systems. With aging, the production of reactive oxygen species (ROS) increases, and this causes lipid, protein, and DNA damage, leading to cellular dysfunction and altered cellular processes. Indeed, oxidative stress plays a key role in the pathogenesis of several chronic disorders, including hepatic diseases, such as non-alcoholic fatty liver disease (NAFLD). NAFLD, the most common liver disorder in the Western world, is characterized by intrahepatic lipid accumulation; is highly prevalent in the aging population; and is closely associated with obesity, insulin resistance, hypertension, and dyslipidemia. Among the risk factors involved in the pathogenesis of NAFLD, the dysbiotic gut microbiota plays an essential role, leading to low-grade chronic inflammation, oxidative stress, and production of various toxic metabolites. The intestinal microbiota is a dynamic ecosystem of microbes involved in the maintenance of physiological homeostasis; the alteration of its composition and function, during aging, is implicated in different liver diseases. Therefore, gut microbiota restoration might be a complementary approach for treating NAFLD. The administration of probiotics, which can relieve oxidative stress and elicit several anti-aging properties, could be a strategy to modify the composition and restore a healthy gut microbiota. Indeed, probiotics could represent a valid supplement to prevent and/or help treating some diseases, such as NAFLD, thus improving the already available pharmacological intervention. Moreover, in aging, intervention of prebiotics and fecal microbiota transplantation, as well as probiotics, will provide novel therapeutic approaches. However, the relevant research is limited, and several scientific research works need to be done in the near future to confirm their efficacy.

Effects of Resveratrol Against Induced Metabolic Syndrome in Rats: Role of Oxidative Stress, Inflammation, and Insulin Resistance

Metabolic syndrome (MS) is a serious health problem associated with an increase in risk factors for hepatic steatosis, which is the most common liver disease today. The goal of this study was to investigate the protective effects of resveratrol against metabolic alterations associated with a high-fat high-fructose diet (HFFD). Thirty-two male rats were randomly divided into four equal groups: control (cont.), metabolic syndrome (MS), resveratrol (Res), and metabolic syndrome treated with resveratrol (MS + Res). Resveratrol was administrated orally at a dose of 30 mg/kg·bw, daily. After 10 weeks, body weight, serum biochemical parameters, hepatic oxidative stress, inflammatory markers, as well as mRNA levels of hepatic genes related to lipid metabolism and insulin signaling were measured. In addition, the liver was examined histopathologically to detect lipid deposition. Increased body weight, hepatic dysfunction, dyslipidemia, hepatic insulin resistance, hepatic oxidative and inflammatory stress conditions, upregulation of mRNA expression level of sterol regulatory element binding protein 1-c (SREBP1-c), and downregulation of mRNA expression levels of peroxisome proliferated activated receptor alpha (PPARα) and insulin receptor substrate-2 (IR-S2) were all observed in the MS rats. Hepatic steatosis was confirmed by hematoxylin and eosin and Oil Red O staining. Administration of resveratrol reduced liver steatosis, oxidative stress, and inflammatory state. Also, it improved lipid profile as well as insulin sensitivity and reverted alterations in hepatic mRNA expression levels of the tested genes. Based on these findings, resveratrol could be proposed as a therapeutic approach for MS prevention.

Honeysuckle Berry (Lonicera caerulea L.) Inhibits Lipase Activity and Modulates the Gut Microbiota in High-Fat Diet-Fed Mice

Honeysuckle berry (HB, Lonicera caerulea L.) is an oriental herbal medicine reported to have beneficial effects on metabolic disorders, such as obesity and non-alcoholic fatty liver disease. The fruit part of HB is rich in anthocyanin, a type of polyphenol. Most studies credit the antioxidant and anti-inflammatory properties of HB as the mechanisms of its effectiveness. This study investigated the inhibitory effects of HB on lipase using an in vitro assay and the modulatory effect of HB on gut microbiota in high-fat diet (HFD)-fed mice. HB inhibited pancreatic lipase activity with IC50 values of approximately 0.47 mg/mL. The fecal triglyceride (TG) levels were higher from the HFD of the HB-fed mice than they were for the control mice. Moreover, the fecal microbiota from the HFD of the HB-fed mice had relatively lower Firmicutes and higher Bacteroidetes than that from the HFD-only mice. These results suggest that HB modulates gut microbiota composition, which may contribute to body fat reduction. Hence, HB could present a useful agent for treating metabolic diseases through lower TG uptake and the regulation of gut microflora.

Lactobacillus plantarum Ameliorates High-Carbohydrate Diet-Induced Hepatic Lipid Accumulation and Oxidative Stress by Upregulating Uridine Synthesis

The overconsumption of carbohydrates induces oxidative stress and lipid accumulation in the liver, which can be alleviated by modulation of intestinal microbiota; however, the underlying mechanism remains unclear. Here, we demonstrated that a strain affiliated with Lactobacillus plantarum (designed as MR1) efficiently attenuated lipid deposition, oxidative stress, as well as inflammatory response, which are caused by high-carbohydrate diet (HC) in fish with poor utilization ability of carbohydrates. Serum untargeted metabolome analysis indicated that pyrimidine metabolism was the significantly changed pathway among the groups. In addition, the content of serum uridine was significantly decreased in the HC group compared with the control group, while it increased by supplementation with L. plantarum MR1. Further analysis showed that addition of L. plantarum MR1 reshaped the composition of gut microbiota and increased the content of intestinal acetate. In vitro experiment showed that sodium acetate could induce the synthesis of uridine in hepatocytes. Furthermore, we proved that uridine could directly ameliorate oxidative stress and decrease liver lipid accumulation in the hepatocytes. In conclusion, this study indicated that probiotic L. plantarum MR1 ameliorated high-carbohydrate diet-induced hepatic lipid accumulation and oxidative stress by increasing the circulating uridine, suggesting that intestinal microbiota can regulate the metabolism of nucleotides to maintain host physiological homeostasis.

A Transcriptomic Response to Lactiplantibacillus plantarum-KCC48 against High-Fat Diet-Induced Fatty Liver Diseases in Mice

The most prevalent chronic liver disorder in the world is fatty liver disease caused by a high-fat diet. We examined the effects of Lactiplantibacillus plantarum-KCC48 on high-fat diet-induced (HFD) fatty liver disease in mice. We used the transcriptome tool to perform a systematic evaluation of hepatic mRNA transcripts changes in high-fat diet (HFD)-fed animals and high-fat diet with L. plantarum (HFLPD)-fed animals. HFD causes fatty liver diseases in animals, as evidenced by an increase in TG content in liver tissues compared to control animals. Based on transcriptome data, 145 differentially expressed genes (DEGs) were identified in the liver of HFD-fed mice compared to control mice. Moreover, 61 genes were differentially expressed in the liver of mice fed the HFLPD compared to mice fed the HFD. Additionally, 43 common DEGs were identified between HFD and HFLPD. These genes were enriched in metabolic processes, retinol metabolism, the PPAR signaling pathway, fatty acid degradation, arachidonic metabolism, and steroid hormone synthesis. Taking these data into consideration, it can be concluded that L. plantarum-KCC48 treatment significantly regulates the expression of genes involved in hepatosteatosis caused by HFD, which may prevent fatty liver disease.

Hepatoprotection of Probiotics Against Non-Alcoholic Fatty Liver Disease in vivo: A Systematic Review

Probiotic supplements have been increasingly reported for their usefulness in delaying the development and progression of non-alcoholic fatty liver disease (NAFLD). Literature on the impact of probiotics on NAFLD covered various aspects of the disease. This study was undertaken to systematically review in vivo findings on hepatoprotection of probiotics against NAFLD. The literature search was performed through Cochrane, PubMed/MEDLINE, Embase, and Web of Science databases. Interventions of known probiotics in NAFLD-induced animal model with at least one measurable NAFLD-related parameter were included. The data were extracted by all authors independently. Quality assessment was conducted using the Systematic Review Center for Laboratory animal Experimentation (SYRCLE's) Risk of Bias (RoB) tool. P-values of measures were compared inter- and intra-study for each parameter. Forty-four probiotic-based studies of NAFLD-induced rodents were shortlisted. The majority of the studies were presented with low/unclear risk of bias. Probiotics improved the histopathology of NAFLD rodents (primary outcome). Most of the probiotic-supplemented NAFLD rodents were presented with mixed effects on serum liver enzymes but with improved hepatic and serum lipid profiles (including increased serum high-density lipoprotein cholesterol). The findings were generally accompanied by downregulation of hepatic lipogenic, oxidative, and inflammatory signallings. Probiotics were found to modulate gut microbiota composition and its products, and intestinal permeability. Probiotics also resulted in better glycaemic control and reduced liver weight. Altogether, the present qualitative appraisals strongly implied the hepatoprotective potential of probiotics against NAFLD in vivo.

Usefulness of Probiotics in the Management of NAFLD: Evidence and Involved Mechanisms of Action from Preclinical and Human Models

The present review aims at analyzing the current evidence regarding probiotic administration for non-alcoholic fatty liver disease (NAFLD) management. Additionally, the involved mechanisms of action modulated by probiotic administration, as well as the eventual limitations of this therapeutic approach and potential alternatives, are discussed. Preclinical studies have demonstrated that the administration of single-strain probiotics and probiotic mixtures effectively prevents diet-induced NAFLD. In both cases, the magnitude of the described effects, as well as the involved mechanisms of action, are comparable, including reduced liver lipid accumulation (due to lipogenesis downregulation and fatty acid oxidation upregulation), recovery of gut microbiota composition and enhanced intestinal integrity. Similar results have also been reported in clinical trials, where the administration of probiotics proved to be effective in the treatment of NAFLD in patients featuring this liver condition. In this case, information regarding the mechanisms of action underlying probiotics-mediated hepatoprotective effects is scarcer (mainly due to the difficulty of liver sample collection). Since probiotics administration represents an increased risk of infection in vulnerable subjects, much attention has been paid to parabiotics and postbiotics, which seem to be effective in the management of several metabolic diseases, and thus represent a suitable alternative to probiotic usage.

Gut Microbiome in Non-Alcoholic Fatty Liver Disease: From Mechanisms to Therapeutic Role

Non-alcoholic fatty liver disease (NAFLD) is considered to be a significant health threat globally, and has attracted growing concern in the research field of liver diseases. NAFLD comprises multifarious fatty degenerative disorders in the liver, including simple steatosis, steatohepatitis and fibrosis. The fundamental pathophysiology of NAFLD is complex and multifactor-driven. In addition to viruses, metabolic syndrome and alcohol, evidence has recently indicated that the microbiome is related to the development and progression of NAFLD. In this review, we summarize the possible microbiota-based therapeutic approaches and highlight the importance of establishing the diagnosis of NAFLD through the different spectra of the disease via the gut-liver axis.

Lactiplantibacillusplantarum ATG-K2 Exerts an Anti-Obesity Effect in High-Fat Diet-Induced Obese Mice by Modulating the Gut Microbiome

Obesity is a major health problem. Compelling evidence supports the beneficial effects of probiotics on obesity. However, the anti-obesity effect of probiotics remains unknown. In this study, we investigated the anti-obesity effects and potential mechanisms of Lactiplantibacillus plantarum ATG-K2 using 3T3-L1 adipocytes and high-fat diet (HFD)-induced obese mice. 3T3-L1 cells were incubated to determine the effect of lipid accumulation with lysate of L. plantarum ATG-K2. Mice were fed a normal fat diet or HFD with L. plantarum ATG-K2 and Orlistat for 8 weeks. L. plantarum ATG-K2 inhibited lipid accumulation in 3T3-L1 adipocytes, and reduced body weight gain, WAT weight, and adipocyte size in HFD-induced obese mice, concurrently with the downregulation of PPARγ, SREBP1c, and FAS and upregulation of PPARα, CTP1, UCP1, Prdm16, and ND5. Moreover, L. plantarum ATG-K2 decreased TG, T-CHO, leptin, and TNF-α levels in the serum, with corresponding gene expression levels in the intestine. L. plantarum ATG-K2 modulated the gut microbiome by increasing the abundance of the Lactobacillaceae family, which increased SCFA levels and branched SCFAs in the feces. L. plantarum ATG-K2 exhibited an anti-obesity effect and anti-hyperlipidemic effect in 3T3-L1 adipocytes and HFD-induced obese mice by alleviating the inflammatory response and regulating lipid metabolism, which may be influenced by modulation of the gut microbiome and its metabolites. Therefore, L. plantarum ATG-K2 can be a preventive and therapeutic agent for obesity.

The impact of alteration in gut microbiome in the pathogenesis of nonalcoholic fatty liver disease

PURPOSE OF REVIEW

We have increasing evidence that alterations of the intestinal microbiome have a strong influence on human health. Previous work has demonstrated the association between changes in the microbiome and metabolic risk factors. One related area of interest is the relationship between dysbiosis and nonalcoholic fatty liver disease (NAFLD), as the global prevalence of NAFLD, and its resultant complications, increases.

RECENT FINDINGS

In this review, we summarize the hypothesized pathophysiology of dysbiosis-mediated progression of NAFLD, including promotion of an inflammatory intestinal environment, increased intestinal permeability, endogenous ethanol production, short-chain fatty acid production, secondary bile acid metabolism, and choline depletion. We also review potential therapeutic interventions of the microbiome to slow or prevent NAFLD progression, including antibiotics, probiotics, prebiotics, fecal microbiota transplant, and farnesoid × receptor agonism.

SUMMARY

Much of the evidence supporting dysbiosis-mediated NAFLD progression has been gathered in high-quality animal trials. There remains a need for additional observational and randomized controlled trials in humans to establish causality between the suspected factors and pathogenesis of NAFLD.

Probiotics in hepatology: An update

The gut-liver axis plays an important role in the pathogenesis of various liver diseases. Probiotics are living bacteria that may be used to correct disorders of this axis. Notable progress has been made in the study of probiotic drugs for the treatment of various liver diseases in the last decade. It has been proven that probiotics are useful for hepatic encephalopathy, but their effects on other symptoms and syndromes of cirrhosis are poorly studied. Their effectiveness in the treatment of metabolic associated fatty liver disease has been shown both in experimental models and in clinical trials, but their effect on the prognosis of this disease has not been described. The beneficial effects of probiotics in alcoholic liver disease have been shown in many experimental studies, but there are very few clinical trials to support these findings. The effects of probiotics on the course of other liver diseases are either poorly studied (such as primary sclerosing cholangitis, chronic hepatitis B and C, and autoimmune hepatitis) or not studied at all (such as primary biliary cholangitis, hepatitis A and E, Wilson's disease, hemochromatosis, storage diseases, and vascular liver diseases). Thus, despite the progress in the study of probiotics in hepatology over the past decade, there are many unexplored and unclear questions surrounding this topic.

Lactobacillus johnsonii BS15 combined with abdominal massage on intestinal permeability in rats with nonalcoholic fatty liver and cell biofilm repair

This study aimed to analyze the effect of lactobacillus johnsonii BS15 (isolation of homemade yogurt from Ahu Hongyuan Grassland) combined with abdominal massage on intestinal permeability in rats with nonalcoholic fatty liver disease (NAFLD) and cell biofilm repair. Forty-five rats were divided randomly into five groups, four of which were fed with high-fat diet to establish NAFLD models. According to the treatment methods, they were grouped into group A (lactic acid bacteria feeding), group B (abdominal massage), group A + B (a combination of the two methods), model group (distilled water feeding), and normal group (distilled water feeding). Then, the pathological indexes of liver and intestinal permeability were observed. FITC-Dextran content of the model group elevated markedly compared with normal group (P < 0.01), indicating that the intestinal permeability of NAFLD rats fed with high-fat diet increased. The intestinal permeability of groups A, B, and A + B was lower sharply than that of model group (P < 0.01), and the effect of group A + B was the most obvious. HE staining of liver tissues showed that combined treatment could improve structural changes in liver cells caused by modeling and restore the normal structure of intestinal cells. Lactobacillus combined with abdominal massage was better than two treatments alone, further promoting the permeability of intestinal mucosa in NAFLD rats and repair biofilm of hepatocytes. The results initially verified the intervention effect of abdominal massage on intestinal mucosal permeability, and further revealed the mechanism of abdominal massage in treatment of NAFLD by improving intestinal mucosal barrier permeability.

Intestinal dysbiosis in nonalcoholic fatty liver disease (NAFLD): focusing on the gut-liver axis

Nonalcoholic fatty liver disease (NAFLD) is one of the most common chronic liver disorders in humans, partly because it is closely related to metabolic disorders of the liver with increasing prevalence. NAFLD begins with hepatic lipid accumulation, which may cause inflammation and eventually lead to fibrosis in the liver. Numerous studies have demonstrated the close relationship between gut dysfunction (especially the gut microbiota and its metabolites) and the occurrence and progression of NAFLD. The bidirectional communication between the gut and liver, named the gut-liver axis, is mainly mediated by the metabolites derived from both the liver and gut through the biliary tract, portal vein, and systemic circulation. Herein, we review the effects of the gut-liver axis on the pathogenesis of NAFLD. We also comprehensively describe the potential molecular mechanisms from the perspective of the role of liver-derived metabolites and gut-related components in hepatic metabolism and inflammation and gut health, respectively. The study provides insights into the mechanisms underlying current summarizations that support the intricate interactions between a disordered gut and NAFLD and can provide novel strategies to lessen the prevalence and consequence of NAFLD.

Probiotics and Prebiotics as a Strategy for Non-Alcoholic Fatty Liver Disease, a Narrative Review

Non-alcoholic fatty liver disease (NAFLD) is a chronic non-communicable disease, with a prevalence of 25% worldwide. This pathology is a multifactorial illness, and is associated with different risks factors, including hypertension, hyperglycemia, dyslipidemia, and obesity. Beside these predisposing features, NAFLD has been related to changes in the microbiota, which favor the disease progression. In this context, the modulation of the gut microbiota has emerged as a new therapeutic target for the prophylaxis and treatment of NAFLD. This review describes the changes in the gut microbiota associated with NAFLD and the effect of probiotics, prebiotics, and synbiotics on the gut microbiota, liver damage, anthropometric parameters, blood lipids, inflammation markers and insulin resistance in these patients.

Lactobacillus plantarum ATG-K2 and ATG-K6 Ameliorates High-Fat with High-Fructose Induced Intestinal Inflammation

Obesity has become a worldwide health problem, and many significant inflammatory markers have been associated with the risk of side effects of obesity and obesity-related diseases. After a normal diet or high-fat diet with high-fructose water (HFHF) for 8 weeks, male Wistar rats were divided randomly into four experimental groups according to body weight. Next, for 8 weeks, a normal diet, HFHF diet, and HFHF diet with L. plantarum strains ATG-K2 or ATG-K6 were administered orally. Compared to the control group, the HFHF diet group showed significantly increased visceral fat, epididymal fat, and liver weight. The mRNA and protein expression levels of FAS and SREBP-1c were higher in the HFHF diet group than in the HFHF diet with L. plantarum strains ATG-K2 and ATG-K6. The HFHF diet with L. plantarum strain ATG-K2 showed significantly decreased inflammatory cytokine expression in the serum and small intestine compared to the HFHF diet group. Furthermore, histological morphology showed minor cell injury, less severe infiltration, and longer villi height in the small intestine ileum of the HFHF diet with L. plantarum strains groups than in the HFHF diet group. These results suggest that L. plantarum strains K2 and K6 may help reduce intestinal inflammation and could be used as treatment alternatives for intestinal inflammatory reactions and obesity.

Diet-Related Alterations of Gut Bile Salt Hydrolases Determined Using a Metagenomic Analysis of the Human Microbiome

The metabolism of bile acid by the gut microbiota is associated with host health. Bile salt hydrolases (BSHs) play a crucial role in controlling microbial bile acid metabolism. Herein, we conducted a comparative study to investigate the alterations in the abundance of BSHs using data from three human studies involving dietary interventions, which included a ketogenetic diet (KD) versus baseline diet (BD), overfeeding diet (OFD) versus underfeeding diet, and low-carbohydrate diet (LCD) versus BD. The KD increased BSH abundance compared to the BD, while the OFD and LCD did not change the total abundance of BSHs in the human gut. BSHs can be classified into seven clusters; Clusters 1 to 4 are relatively abundant in the gut. In the KD cohort, the levels of BSHs from Clusters 1, 3, and 4 increased significantly, whereas there was no notable change in the levels of BSHs from the clusters in the OFD and LCD cohorts. Taxonomic studies showed that members of the phyla Bacteroidetes, Firmicutes, and Actinobacteria predominantly produced BSHs. The KD altered the community structure of BSH-active bacteria, causing an increase in the abundance of Bacteroidetes and decrease in Actinobacteria. In contrast, the abundance of BSH-active Bacteroidetes decreased in the OFD cohort, and no significant change was observed in the LCD cohort. These results highlight that dietary patterns are associated with the abundance of BSHs and community structure of BSH-active bacteria and demonstrate the possibility of manipulating the composition of BSHs in the gut through dietary interventions to impact human health.

Understanding the Effects of Gut Microbiota Dysbiosis on Nonalcoholic Fatty Liver Disease and the Possible Probiotics Role: Recent Updates

Nonalcoholic fatty liver disease (NAFLD) is leading chronic liver syndrome worldwide. Gut microbiota dysbiosis significantly contributes to the pathogenesis and severity of NAFLD. However, its role is complex and even unclear. Treatment of NAFLD through chemotherapeutic agents have been questioned because of their side effects on health. In this review, we highlighted and discussed the current understanding on the importance of gut microbiota, its dysbiosis and its effects on the gut-liver axis and gut mucosa. Further, we discussed key mechanisms involved in gut dysbiosis to provide an outline of its role in progression to NAFLD and liver cirrhosis. In addition, we also explored the potential role of probiotics as a treatment approach for the prevention and treatment of NAFLD. Based on the latest findings, it is evident that microbiota targeted interventions mostly the use of probiotics have shown promising effects and can possibly alleviate the gut microbiota dysbiosis, regulate the metabolic pathways which in turn inhibit the progression of NAFLD through the gut-liver axis. However, very limited studies in humans are available on this issue and suggest further research work to identify a specific core microbiome association with NAFLD and to discover its mechanism of pathogenesis, which will help to enhance the therapeutic potential of probiotics to NAFLD.

Novel Lactobacillus reuteri HI120 Affects Lipid Metabolism in C57BL/6 Obese Mice

Intestinal probiotics are a primary focus area of current medical research. Probiotics such as bifidobacteria and lactobacilli can positively impact obesity and other metabolic diseases by directly or indirectly affecting lipid metabolism. However, the precise mechanisms of these effects remain unclear. In our previous work, the novel strain Lactobacillus reuteri HI120 was isolated and identified. HI120 expresses high levels of linoleic isomerase, resulting in the production of large amounts of conjugated linoleic acid (CLA) when mixed with linoleic acid (LA). As HI120 can efficiently transform LA into CLA, the effect of HI120 on the lipid metabolism in C57BL/6 obese mice was studied and the underlying molecular mechanism was explored in vitro. The results revealed no significant change in the diet, body weight, and serum triglyceride levels in mice. However, serum cholesterol levels were significantly decreased. The underlying mechanism may involve a CLA-mediated reduction in the gene expression levels of NPC1L1, SREBP-2, and HMG-CR, resulting in reduced cholesterol synthesis and absorption. Thus, HI120 can be developed as a potential probiotic formulation. After oral administration, LA from certain food sources can be converted into CLA in the human intestine to contribute to the prevention and treatment of obesity and hyperlipidemia.

Gut Microbiota Metabolites in NAFLD Pathogenesis and Therapeutic Implications

Gut microbiota dysregulation plays a key role in the pathogenesis of nonalcoholic fatty liver disease (NAFLD) through its metabolites. Therefore, the restoration of the gut microbiota and supplementation with commensal bacterial metabolites can be of therapeutic benefit against the disease. In this review, we summarize the roles of various bacterial metabolites in the pathogenesis of NAFLD and their therapeutic implications. The gut microbiota dysregulation is a feature of NAFLD, and the signatures of gut microbiota are associated with the severity of the disease through altered bacterial metabolites. Disturbance of bile acid metabolism leads to underactivation of bile acid receptors FXR and TGR5, causal for decreased energy expenditure, increased lipogenesis, increased bile acid synthesis and increased macrophage activity. Decreased production of butyrate results in increased intestinal inflammation, increased gut permeability, endotoxemia and systemic inflammation. Dysregulation of amino acids and choline also contributes to lipid accumulation and to a chronic inflammatory status. In some NAFLD patients, overproduction of ethanol produced by bacteria is responsible for hepatic inflammation. Many approaches including probiotics, prebiotics, synbiotics, faecal microbiome transplantation and a fasting-mimicking diet have been applied to restore the gut microbiota for the improvement of NAFLD.