Metabolic endotoxemia initiates obesity and insulin resistance

Identifying the location-dependent adipose tissue bacterial DNA signatures in obese patients that predict body weight loss

Recent sets of evidence have described profiles of 16S rDNA sequences in host tissues, notably in fat pads that are significantly overrepresented and can serve as signatures of metabolic disease. However, these recent and original observations need to be further detailed and functionally defined. Here, using state-of-the-art targeted DNA sequencing and discriminant predictive approaches, we describe, from the longitudinal FLORINASH cohort of patients who underwent bariatric surgery, visceral, and subcutaneous fat pad-specific bacterial 16SrRNA signatures. The corresponding Porphyromonadaceae, Campylobacteraceae, Prevotellaceae, Actimomycetaceae, Veillonellaceae, Anaerivoracaceae, Fusobacteriaceae, and the Clostridium family XI 16SrRNA DNA segment profiles are signatures of the subcutaneous adipose depot while Pseudomonadaceae and Micrococcacecae, 16SrRNA DNA sequence profiles characterize the visceral adipose depot. In addition, we have further identified that a specific pre-bariatric surgery adipose tissue bacterial DNA signature predicts the efficacy of body weight loss in obese patients 5-10 years after the surgery. 16SrRNA signatures discriminate (ROC ~ 1) the patients who did not maintain bodyweight loss and those who did. Second, from the 16SrRNA sequences we infer potential pathways suggestive of catabolic biochemical activities that could be signatures of subcutaneous adipose depots that predict body weight loss.

Multifunctional dietary approach reduces intestinal inflammation in relation with changes in gut microbiota composition in subjects at cardiometabolic risk: the SINFONI project

The development of cardiometabolic (CM) diseases is associated with chronic low-grade inflammation, partly linked to alterations of the gut microbiota (GM) and reduced intestinal integrity. The SINFONI project investigates a multifunctional (MF) nutritional strategy's impact combining different bioactive compounds on inflammation, GM modulation and CM profile. In this randomized crossover-controlled study, 30 subjects at CM-risk consumed MF cereal-products, enriched with polyphenols, fibers, slowly-digestible starch, omega-3 fatty acids or Control cereal-products (without bioactive compounds) for 2 months. Metabolic endotoxemia (lipopolysaccharide (LPS), lipopolysaccharide-binding protein over soluble cluster of differentiation-14 (LBP/sCD14), systemic inflammation and cardiovascular risk markers, intestinal inflammation, CM profile and response to a one-week fructose supplementation, were assessed at fasting and post mixed-meal. GM composition and metabolomic analysis were conducted. Mixed linear models were employed, integrating time (pre/post), treatment (MF/control), and sequence/period. Compared to control, MF intervention reduced intestinal inflammation (fecal calprotectin, p = 0.007) and endotoxemia (fasting LPS, p < 0.05), without alteration of systemic inflammation. MF decreased serum branched-chain amino acids compared to control (p < 0.05) and increased B.ovatus, B.uniformis, A.butyriciproducens and unclassified Christensenellaceae.CAG-74 (p < 0.05). CM markers were unchanged. A 2-month dietary intervention combining multiple bioactive compounds improved intestinal inflammation and induced GM modulation. Such strategy appears as an effective strategy to target low-grade inflammation through multi-target approach.

Obesogenic effects of six classes of emerging contaminants

There is growing concern about the concept that exposure to environmental chemicals may be contributing to the obesity epidemic. However, there is no consensus on the obesogenic effects of emerging contaminants from a toxicological and environmental perspective. The potential human exposure and experimental evidence for obesogenic effects of emerging contaminants need to be systematically discussed. The main objective of this review is to provide recommendations for further subsequent policy development following a critical analysis of the literature for humans and experimental animals exposed to emerging contaminants. This article reviews human exposure to emerging contaminants (with a focus on antimicrobials, preservatives, water and oil repellents, flame retardants, antibiotics and bisphenols) and the impact of emerging contaminants on obesity. These emerging contaminants have been widely detected in human biological samples. Epidemiological studies provide evidence linking exposure to emerging contaminants to the risks of obesity in humans. Studies based on animal models and adipose cells show the obesogenic effects of emerging contaminants and identify modes of action by which contaminants may induce changes in body fat accumulation and lipid metabolic homeostasis. Some knowledge gaps in this area and future directions for further investigation are discussed.

Grape pomace extract attenuates high fat diet-induced endotoxemia and liver steatosis in mice

Obesity is a prominent global health concern associated with chronic inflammation and metabolic disorders, such as insulin resistance, type 2 diabetes, and non-alcoholic fatty liver disease (NAFLD). Excessive consumption of saturated fats exacerbates these conditions by increasing intestinal barrier permeability and circulating endotoxins. This study aims to investigate, in a murine model of high-fat diet (HFD)-induced obesity, the potential beneficial effects of a grape pomace extract (GPE), rich in phenolic compounds, at mitigating endotoxemia, and liver steatosis. Underlying mechanisms were characterized in an in vitro model of intestinal inflammation and permeabilization, as induced by tumor necrosis factor alpha (TNFα) in Caco-2 cell monolayers. Consumption of a HFD (60% calories from fat) for 13 weeks induced obesity, insulin resistance, and liver damage, evidenced by higher levels of plasma alanine aminotransferase (ALT), hepatic triglycerides content, and steatosis. In addition, HFD caused metabolic endotoxemia, hepatic toll-like receptor 4 (TLR4) upregulation and inflammation. GPE supplementation significantly reduced body weight and subcutaneous and visceral adipose tissue weight, and attenuated metabolic dysregulation. Furthermore, GPE decreased circulating LPS levels and mitigated HFD-mediated hepatic TLR4 upregulation, nuclear factor kappa B (NF-κB) activation, and downstream expression of proteins involved in oxidative stress and inflammation (NOX4, TNFα, and F4/80). In Caco-2 cells, GPE mitigated TNFα-induced monolayer permeabilization, decreased tight junction (TJ) protein levels, enhanced cellular oxidant production, activated redox-sensitive signaling, i.e., NF-κB and ERK1/2, and increased NOX1 and MLCK mRNA levels, the latter being a key regulator of monolayer permeability. The above findings suggest that GPE may protect against HFD-induced obesity and associated metabolic dysfunction (insulin resistance and NAFLD) by modulating intestinal barrier integrity and related endotoxemia.

Carnosic acid reduces lipid content, enhances gut health, and modulates microbiota composition and metabolism in diet-induced obese mice

Carnosic acid (CA) is a bioactive phenolic diterperne compound found in sage and rosemary. The present study investigated the beneficial effects of CA (50 and 100 mg per kg bw) in diet-induced obese mice and the underlying mechanisms of action. After the intervention, the physiology, lipid metabolism, and tissue morphology, as well as the inflammation, gut microbiota, and metabolomics in the colon were measured. We found that CA improved the composition and metabolism of the gut microbiota in obese mice, with Akkermansia being the dominant bacterium negatively correlated with obesity and various fecal metabolites. Regarding the intestinal barrier function, CA promoted the expression of tight junction proteins and inhibited the TLR4/MyD88/NF-κB signaling pathway in obese mice to alleviate colonic inflammation. These results suggest that CA improved multiple aspects of gut health in diet-induced obesity in mice, providing a scientific basis for future clinical studies in humans.

Gut Microbiota and Metabolic Biomarkers Associated With Longevity

The dynamic balance between pro- and anti-inflammatory networks decreases as individuals age, and intestinal dysbiosis can initiate and maintain low-grade systemic inflammation. Interactions between the microbiota and humans occur from the beginning of life and, in general, the diversity of microbiota decreases with aging. The microbiome produces different metabolites with systemic effects, including immune system regulation. This understanding will be useful in controlling inflammation and preventing metabolic changes. Therefore, this review aims to identify the main metabolites synthesized by the intestinal microbiota to be used as biomarkers associated with longevity. This is a narrative review using scientific articles published in the last 10 years in the following databases: PubMed, Scielo, and Lilacs, using the Boolean operators "and" or "or." For this review, we identified 5 articles. The main metabolites described in the literature to date are organic acids, bile acids (BAs), short-chain fatty acids, branched-chain amino acids, trimethylamine N-oxide (TMAO), and derivatives of tryptophan and indole. Among these, the only ones not yet well characterized in studies on longevity were BAs and TMAO. Glutamate and p-cresol were also highlighted in the literature, with a negative association with longevity. The others showed an association, mostly positive, and can be used as potential biomarkers correlated with healthy aging and, if better studied, as targets for intervention to promote health and well-being.

Early-life antibiotic exposure aggravates hepatic steatosis through enhanced endotoxemia and lipotoxic effects driven by gut Parabacteroides

Compelling evidence supports a link between early-life gut microbiota and the metabolic outcomes in later life. Using an early-life antibiotic exposure model in BALB/c mice, we investigated the life-course impact of prenatal and/or postnatal antibiotic exposures on the gut microbiome of offspring and the development of metabolic dysfunction-associated steatotic liver disease (MASLD). Compared to prenatal antibiotic exposure alone, postnatal antibiotic exposure more profoundly affected gut microbiota development and succession, which led to aggravated endotoxemia and metabolic dysfunctions. This was primarily resulted from the overblooming of gut Parabacteroides and hepatic accumulation of cytotoxic lysophosphatidyl cholines (LPCs), which acted in conjunction with LPS derived from Parabacteroides distasonis (LPS_PA) to induce cholesterol metabolic dysregulations, endoplasmic reticulum (ER) stress and apoptosis. Integrated serum metabolomics, hepatic lipidomics and transcriptomics revealed enhanced glycerophospholipid hydrolysis and LPC production in association with the upregulation of PLA2G10, the gene controlling the expression of the group X secretory Phospholipase A2s (sPLA2-X). Taken together, our results show microbial modulations on the systemic MASLD pathogenesis and hepatocellular lipotoxicity pathways following early-life antibiotic exposure, hence help inform refined clinical practices to avoid any prolonged maternal antibiotic administration in early life and potential gut microbiota-targeted intervention strategies.

Gut Microbiota Predicts Treatment Response to Empagliflozin Among MASLD Patients Without Diabetes Mellitus

BACKGROUND AND AIM

We aimed to investigate whether gut microbiota could predict the treatment response to pharmacological agents among metabolic dysfunction-associated steatotic liver disease (MASLD) patients without diabetes mellitus (DM), as data are lacking.

METHODS

We prospectively followed up non-diabetic MASLD patients who used empagliflozin. Clinical, anthropometric, laboratory assessments and magnetic resonance imaging-proton density fat fraction (MRI-PDFF) were performed from baseline to week 52 (EOT). Baseline stool samples were collected, and shotgun DNA metagenomic sequencing was performed to profile microbiome. The primary outcome was treatment response to empagliflozin at EOT, defined as MRI-PDFF decline ≥ 30% at EOT from baseline. Linear discriminant analysis [LDA] effect size was used to identify putative bacterial species. Multivariable logistic regression was used to derive adjusted odds ratio (aOR) of outcome with bacterial species by adjusting for clinical factors.

RESULTS

Twenty-two (48.9%) of 45 patients (median age: 56.9 years [IQR: 51.0-63.2]; male: 23 [51.1%]) achieved treatment response at EOT. There was difference in alpha diversity (Shannon index: p < 0.001; Simpson index: p = 0.001) and beta diversity (p = 0.048) in baseline microbiome between treatment response and non-response groups. Faecalibacterium prausnitzii (log10LDAscore = 4.27), Lachnospira pectinoschiza (log10LDAscore = 3.99), Anaerostipes hadrus (log10LDAscore = 3.98), Roseburia faecis (log10LDAscore = 3.97), Roseburia inulinivorans (log10LDAscore = 3.58) and Agathobaculum butyriciproducens (log10LDAscore = 2.77) were enriched in the treatment response group. L. pectinoschiza (aOR: 34.1; p = 0.015), A. hadrus (aOR:35.0; p = 0.032) and A. butyriciproducens (aOR:22.3; p = 0.023) independently predicted treatment response but not clinical factors. These three species collectively predicted treatment response with AUROC of 0.89 (95% CI: 0.80-0.99).

CONCLUSIONS

Certain gut bacterial species, particularly the combination of A. hadrus, L. pectinoschiza and A. butyriciproducens, may predict treatment response to empagliflozin in MAFLD patients without DM.

Inappropriate diet and hygiene status affect the progression of diabetic kidney disease by causing dysbiosis

OBJECTIVE

Although the effects of an unhealthy diet on the risks of diabetes and its renal complications are well understood, the effects of hygiene status have not been fully elucidated.

RESEARCH METHODS AND PROCEDURES

We created four groups of mice according to the diet fed (standard [SD] or high-fat [HFD]) and their living environment (conventional [CV] or specific pathogen-free [SPF]), and characterized the extent of their kidney pathology, their gut microbiota, and their fecal short-chain fatty acid (SCFA) concentrations.

RESULTS

The body masses and glycated hemoglobin levels of the HFD and CV groups were significantly higher than those of the SD and SPF groups, respectively. The renal mRNA expression of markers of inflammation and fibrosis and the protein level of CD31 were higher in the HFD and CV groups than in the SD and SPF groups, respectively. Although the alpha diversities and total SCFA concentrations of the HFD and CV groups were significantly lower than those of the SD and SPF groups, respectively, the mRNA expression of genes involved in inflammation, innate immunity, tight junctions, and glucose transporters in the gut was only affected by HFD.

CONCLUSIONS

Gut microbial dysbiosis, owing to the combined effects of inappropriate diet and excessive hygiene, accompanied by lower intestinal SCFA production, may contribute to the development and/or progression of diabetes and diabetic kidney disease through the induction of inflammation and fibrosis.

Environmental contamination by bisphenols: From plastic production to modulation of the intestinal morphophysiology in experimental models

Bisphenols are frequently found in a range of plastic products and have been associated with the development of diseases such as diabetes mellitus type 2 and obesity. These compounds are known as endocrine disruptors and have led to restrictions on their use due to their presence in the environment and their association with non-communicable chronic diseases. The gastrointestinal tract, being the primary site of food and water absorption, is particularly vulnerable to the effects of bisphenols. For this reason, a review of studies showing associations between bisphenols exposure and adverse effects in the gut microbiota, morphology tissue, gut permeability, and on the enteric nervous system was carried out. We have included perinatal studies and in different adult experimental models. The effects of bisphenol exposure on the gut microbiota are complex and varied. Bisphenol exposure generally leads to a decrease in microbial diversity and may impact the integrity of the intestinal barrier, resulting in elevated levels of inflammation, changes in morphological and metabolic characteristics of the gut, modifications in tight junction expression, and changes in goblet cell expression. In addition, bisphenol exposure in the perinatal phase can lead to important intestinal changes, including increased colonic inflammation and decreased colonic paracellular permeability.

Gut microbiota dysbiosis in Alzheimer's disease (AD): Insights from human clinical studies and the mouse AD models

Alzheimer's Disease (AD) is a debilitating neurocognitive disorder with an unclear underlying mechanism. Recent studies have implicated gut microbiota dysbiosis with the onset and progression of AD. The connection between gut microbiota and AD can significantly affect the prevention and treatment of AD patients. This systematic review summarizes primary outcomes of human and mouse AD models concerning gut microbiota alterations. A systematic literature search in February through March 2023 was conducted on PubMed, Embase, and Web of Science. We identified 711 as potential manuscripts of which 672 were excluded because of irrelevance to the identified search criteria. Primary outcomes include microbiota compositions of control and AD models in humans and mice. In total, 39 studies were included (19 mouse and 20 human studies), published between 2017 and 2023. We included studies involving well-established mice models of AD (5xFAD, 3xTg-AD, APP/PS1, Tg2576, and APPPS2) which harbor mutations and genes that drive the formation of Aß plaques. All human studies were included on those with AD or mild cognitive impairment. Among alterations in gut microbiota, most studies found a decreased abundance of the phyla Firmicutes and Bifidobacteria, a genus of the phylum Actinomycetota. An increased abundance of the phyla Bacteroidetes and Proteobacteria were identified in animal and human studies. Studies indicated that gut microbiota alter the pathogenesis of AD through its impact on neuroinflammation and permeability of the gastrointestinal tract. The ensuing increase in blood-brain barrier permeability may accelerate Aβ penetrance and formation of neuritic plaques that align with the amyloid hypothesis of AD pathogenesis. Further studies should assess the relationship between gut microbiota and AD progression and therapy preserving beneficial gut microbiota.

Gut microbial metabolites: The bridge connecting diet and atherosclerosis, and next-generation targets for dietary interventions

Mounting evidence indicates that gut microbial metabolites are central hubs linking the gut microbiota to atherosclerosis (AS). Gut microbiota enriched with pathobiont bacteria responsible for producing metabolites like trimethylamine N-oxide and phenylacetylglutamine are related to an increased risk of cardiovascular events. Furthermore, gut microbiota enriched with bacteria responsible for producing short-chain fatty acids, indole, and its derivatives, such as indole-3-propionic acid, have demonstrated AS-protective effects. This study described AS-related gut microbial composition and how microbial metabolites affect AS. Summary findings revealed gut microbiota and their metabolites-targeted diets could benefit AS treatment. In conclusion, dietary interventions centered on the gut microbiota represent a promising strategy for AS treatment, and understanding diet-microbiota interactions could potentially be devoted to developing novel anti-AS therapies.

Deciphering the tripartite interaction of urbanized environment, gut microbiome and cardio-metabolic disease

The world is experiencing a sudden surge in urban population, especially in developing Asian and African countries. Consequently, the global burden of cardio-metabolic disease (CMD) is also rising owing to gut microbiome dysbiosis due to urbanization factors such as mode of birth, breastfeeding, diet, environmental pollutants, and soil exposure. Dysbiotic gut microbiome indicated by altered Firmicutes to Bacteroides ratio and loss of beneficial short-chain fatty acids-producing bacteria such as Prevotella, and Ruminococcus may disrupt host-intestinal homeostasis by altering host immune response, gut barrier integrity, and microbial metabolism through altered T-regulatory cells/T-helper cells balance, activation of pattern recognition receptors and toll-like receptors, decreased mucus production, elevated level of trimethylamine-oxide and primary bile acids. This leads to a pro-inflammatory gut characterized by increased pro-inflammatory cytokines such as tumour necrosis factor-α, interleukin-2, Interferon-ϒ and elevated levels of metabolites or metabolic endotoxemia due to leaky gut formation. These pathophysiological characteristics are associated with an increased risk of cardio-metabolic disease. This review aims to comprehensively elucidate the effect of urbanization on gut microbiome-driven cardio-metabolic disease. Additionally, it discusses targeting the gut microbiome and its associated pathways via strategies such as diet and lifestyle modulation, probiotics, prebiotics intake, etc., for the prevention and treatment of disease which can potentially be integrated into clinical and professional healthcare settings.

The impact of perinatal maternal stress on the maternal and infant gut and human milk microbiomes: A scoping review

BACKGROUND

Perinatal maternal stress, which includes both psychological and physiological stress experienced by healthy women during pregnancy and the postpartum period, is becoming increasingly prevalent. Infant early exposure to adverse environments such as perinatal stress has been shown to increase the long-term risk to metabolic, immunologic and neurobehavioral disorders. Evidence suggests that the human microbiome facilitates the transmission of maternal factors to infants via the vaginal, gut, and human milk microbiomes. The colonization of aberrant microorganisms in the mother's microbiome, influenced by the microbiome-brain-gut axis, may be transferred to infants during a critical early developmental period. This transfer may predispose infants to a more inflammatory-prone microbiome which is associated with dysregulated metabolic process leading to adverse health outcomes. Given the prevalence and potential impact of perinatal stress on maternal and infant health, with no systematic mapping or review of the data to date, the aim of this scoping review is to gather evidence on the relationship between perinatal maternal stress, and the human milk, maternal, and infant gut microbiomes.

METHODS

This is an exploratory mapping scoping review, guided by the Joanna Briggs Institute's methodology along with use of the Prisma Scr reporting guideline. A comprehensive search was conducted using the following databases, CINAHL Complete; MEDLINE; PsycINFO, Web of Science and Scopus with a protocol registered with Open Science Framework DOI 10.17605/OSF.IO/5SRMV.

RESULTS

After screening 1145 papers there were 7 paper that met the inclusion criteria. Statistically significant associations were found in five of the studies which identify higher abundance of potentially pathogenic bacteria such as Erwinia, Serratia, T mayombie, Bacteroides with higher maternal stress, and lower levels of stress linked to potentially beneficial bacteria such Lactococcus, Lactobacillus, Akkermansia. However, one study presents conflicting results where it was reported that higher maternal stress was linked to the prevalence of more beneficial bacteria.

CONCLUSION

This review suggests that maternal stress does have an impact on the alteration of abundance and diversity of influential bacteria in the gut microbiome, however, it can affect colonisation in different ways. These bacterial changes have the capacity to influence long term health and disease. The review analyses data collection tools and methods, offers potential reasons for these findings as well as suggestions for future research.

Gut Microbiome Regulation of Gut Hormone Secretion

The gut microbiome, comprising bacteria, viruses, fungi, and bacteriophages, is one of the largest microbial ecosystems in the human body and plays a crucial role in various physiological processes. This review explores the interaction between the gut microbiome and enteroendocrine cells (EECs), specialized hormone-secreting cells within the intestinal epithelium. EECs, which constitute less than 1% of intestinal epithelial cells, are key regulators of gut-brain communication, energy metabolism, gut motility, and satiety. Recent evidence shows that gut microbiota directly influence EEC function, maturation, and hormone secretion. For instance, commensal bacteria regulate the production of hormones like glucagon-like peptide 1 and peptide YY by modulating gene expression and vesicle cycling in EE cells. Additionally, metabolites such as short-chain fatty acids, derived from microbial fermentation, play a central role in regulating EEC signaling pathways that affect metabolism, gut motility, and immune responses. Furthermore, the interplay between gut microbiota, EECs, and metabolic diseases, such as obesity and diabetes, is examined, emphasizing the microbiome's dual role in promoting health and contributing to disease states. This intricate relationship between the gut microbiome and EECs offers new insights into potential therapeutic strategies for metabolic and gut disorders.

A review of gut failure as a cause and consequence of critical illness

In critical illness, all elements of gut function are perturbed. Dysbiosis develops as the gut microbial community loses taxonomic diversity and new virulence factors appear. Intestinal permeability increases, allowing for translocation of bacteria and/or bacterial products. Epithelial function is altered at a cellular level and homeostasis of the epithelial monolayer is compromised by increased intestinal epithelial cell death and decreased proliferation. Gut immunity is impaired with simultaneous activation of maladaptive pro- and anti-inflammatory signals leading to both tissue damage and susceptibility to infections. Additionally, splanchnic vasoconstriction leads to decreased blood flow with local ischemic changes. Together, these interrelated elements of gastrointestinal dysfunction drive and then perpetuate multi-organ dysfunction syndrome. Despite the clear importance of maintaining gut homeostasis, there are very few reliable measures of gut function in critical illness. Further, while multiple therapeutic strategies have been proposed, most have not been shown to conclusively demonstrate benefit, and care is still largely supportive. The key role of the gut in critical illness was the subject of the tenth Perioperative Quality Initiative meeting, a conference to summarize the current state of the literature and identify key knowledge gaps for future study. This review is the product of that conference.

Microbiota and Inflammatory Markers: A Review of Their Interplay, Clinical Implications, and Metabolic Disorders

The human microbiota, a complex ecosystem of microorganisms, plays a pivotal role in regulating host immunity and metabolism. This review investigates the interplay between microbiota and inflammatory markers, emphasizing their impact on metabolic and autoimmune disorders. Key inflammatory biomarkers, such as C-reactive protein (CRP), interleukin-6 (IL-6), lipopolysaccharides (LPS), zonulin (ZO-1), and netrin-1 (Ntn1), are discussed in the context of intestinal barrier integrity and chronic inflammation. Dysbiosis, characterized by alterations in microbial composition and function, directly modulates the levels and activity of these biomarkers, exacerbating inflammatory responses and compromising epithelial barriers. The disruption of microbiota is further correlated with increased intestinal permeability and chronic inflammation, serving as a precursor to conditions like type 2 diabetes (T2D), obesity, and non-alcoholic fatty liver disease. Additionally, this review examines therapeutic strategies, including probiotics and prebiotics, designed to restore microbial balance, mitigate inflammation, and enhance metabolic homeostasis. Emerging evidence positions microbiota-targeted interventions as critical components in the advancement of precision medicine, offering promising avenues for diagnosing and treating inflammatory and metabolic disorders.

An umbrella review of meta-analyses on the effects of microbial therapy in metabolic dysfunction-associated steatotic liver disease

BACKGROUND

Current pharmacological treatments for metabolic dysfunction-associated steatotic liver disease (MASLD) are often accompanied by adverse side effects. Consequently, probiotics, prebiotics, and synbiotics, which are bioactive compounds from fermented foods and offer fewer side effects, have garnered significant attention as alternative therapeutic strategies.

OBJECTIVE

This study aims to assess the efficacy of microbial therapies-probiotics, prebiotics, and synbiotics-in managing MASLD and to identify the optimal treatment modality for various clinical indicators through a comprehensive umbrella review of meta-analyses.

METHODS

A thorough literature search was conducted across PubMed, Web of Science, EMBASE, Cochrane Library, and Scopus to identify 23 meta-analyses over 18,999 MASLD patients as of November 2024.

RESULTS

The findings indicate that microbial treatments positively influence levels of total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C), alanine aminotransferase (ALT), aspartate aminotransferase (AST), gamma-glutamyl transferase (GGT), homeostasis model assessment of insulin resistance (HOMA-IR), insulin, tumour necrosis factor-alpha (TNF-α), C-reactive protein (CRP), and body mass index (BMI) in MASLD patients. Notably, probiotics were most effective in reducing TC, ALT, AST, GGT, insulin, TNF-α, and BMI; prebiotics were most effective in reducing TG; and synbiotics were most effective in reducing LDL-C, HOMA-IR, and CRP.

CONCLUSION

Our study provides robust evidence for microbial treatments of MASLD, enabling targeted interventions for different indicators.

Therapeutic Strategies to Modulate Gut Microbial Health: Approaches for Chronic Metabolic Disorder Management

Numerous recent studies have suggested that the composition of the intestinal microbiota can trigger metabolic disorders, such as diabetes, prediabetes, obesity, metabolic syndrome, sarcopenia, dyslipidemia, hyperhomocysteinemia, and non-alcoholic fatty liver disease. Since then, considerable effort has been made to understand the link between the composition of intestinal microbiota and metabolic disorders, as well as the role of probiotics in the modulation of the intestinal microbiota. The aim of this review was to summarize the reviews and individual articles on the state of the art regarding ideal therapy with probiotics and prebiotics in order to obtain the reversion of dysbiosis (alteration in microbiota) to eubiosis during metabolic diseases, such as diabetes, prediabetes, obesity, hyperhomocysteinemia, dyslipidemia, sarcopenia, and non-alcoholic fatty liver diseases. This review includes 245 eligible studies. In conclusion, a condition of dysbiosis, or in general, alteration of the intestinal microbiota, could be implicated in the development of metabolic disorders through different mechanisms, mainly linked to the release of pro-inflammatory factors. Several studies have already demonstrated the potential of using probiotics and prebiotics in the treatment of this condition, detecting significant improvements in the specific symptoms of metabolic diseases. These findings reinforce the hypothesis that a condition of dysbiosis can lead to a generalized inflammatory picture with negative consequences on different organs and systems. Moreover, this review confirms that the beneficial effects of probiotics on metabolic diseases are promising, but more research is needed to determine the optimal probiotic strains, doses, and administration forms for specific metabolic conditions.

Increased plasma lipopolysaccharide-binding protein and altered inflammatory mediators reveal a pro-inflammatory state in overweight women

BACKGROUND

Chronic low-grade inflammation has been recognized as an underlying event linking obesity to diabetes and cardiovascular disease (CVD). However, inflammatory alterations in individuals and specifically women who are overweight remain understudied. Providing relevant insights is of substantial interest for women's cardiovascular health.

METHODS

We determined the levels of key circulating biomarkers of innate immune responses and inflammation, including lipopolysaccharide-binding protein (LBP), C-reactive protein (CRP), interleukin-6 (IL-6), leptin, and adiponectin in adult female subjects who were lean (n = 20) or overweight (n = 20) and had high cholesterol and/or high blood pressure - two important conventional risk factors for CVD.

RESULTS

Plasma levels of LBP were significantly higher in the overweight group compared with the lean group (P = 0.017). The levels of CRP were also significantly higher in overweight subjects (P = 0.023), as were IL-6 (P = 0.016) and leptin (P = 0.004), pro-inflammatory mediators associated with cardiovascular risk. Levels of adiponectin, an adipokine with anti-inflammatory and anti-atherogenic functions, were significantly lower in the overweight group (P = 0.006). The leptin/adiponectin ratio, a preferential atherogenic marker was significantly increased in women who are overweight (P = 0.0007). LBP, CRP, leptin, IL-6, leptin, and adiponectin levels significantly correlated with BMI, but not with age and there was a significant correlation between LBP and IL-6 levels and LBP and CRP levels.

CONCLUSIONS

These results reveal the presence of a pro-inflammatory state in overweight women and are of interest for further studies with the goal for improved understanding of cardiovascular health risks in women.

The Joint Contribution of Host Genetics and Probiotics to Pig Growth Performance

Intestinal probiotics significantly regulate the growth performance of their host, with their composition being influenced by various factors. While many studies have explored how gut microbiota composition affects growth traits such as body weight and BMI, the research on probiotics influenced by host genetic factors, and their subsequent impact on host growth performance, remains limited. To address this research gap, we collected fecal and tissue samples, as well as phenotypic data, from 193 Yunong black pigs at 280 days of age. We then sequenced and genotyped all 193 subjects using the 50K SNP BeadChip, yielding a comprehensive dataset for genetic and microbiome analyses. We then employed microbiome-wide association studies (MWAS), a meta-analysis, and microbiome-wide genetic association studies (MGWASs) to examine the relationship between host genetics, gut microbiota, and growth performance. Four key microbial taxa, namely Coprococcus, Blautia, Ruminococcaceae, and RF16, were identified as being significantly associated with body weight and BMI. The MGWAS analysis revealed that both Coprococcus and Ruminococcaceae were significantly associated with host genomic variations. A total of four important single nucleotide polymorphisms (SNPs) were mapped to two chromosomal regions, corresponding to three candidate genes. Among them, the candidate genes INPP4B, SCOC, and PABPC4L were identified as being related to the abundance of key microbes. This study provides new insights into the joint contributions of host genetics and probiotics to host growth traits, offering theoretical guidance and data support for the development of efficient and targeted breeding strategies.

Alleviative effect of probiotics and prebiotics on dry eye in type 2 diabetic mice through the gut-eye axis

Diabetes Mellitus (DM) is a metabolic disease that manifests as a state of "chronic low-grade inflammation". Patients with DM have a disorder of intestinal flora. There is a discernible correlation between this disorder of intestinal flora and the onset and progression of eye diseases, which offers novel insights into treating eye diseases through the modulation of intestinal flora. Here, we demonstrated that a high-fat diet and streptozotocin injection-induced intestinal microbiota dysbiosis can lead to dry eye-like manifestations in T2DM mice. Probiotic and prebiotic treatments not only alleviated intestinal inflammation and barrier disruption, but also mitigated damage to the lacrimal barrier and suppressed immune cell infiltration and inflammatory responses. Additional mechanism investigation found that probiotics and prebiotics inhibited the TLR4/NF-κB signaling pathway and its downstream pro-inflammatory products both in the lacrimal gland and colon. 16S RNA sequencing identified a reduction in the bacterial genera Akkermansia and Lactobacillus in the fecal samples of DM mice. By contrast, treatment with probiotics and prebiotics led to a reshaping of the intestinal microbial community and a reduction in bile acid metabolites, such as taurocholic acid and deoxycholic acid. Our current study demonstrates that probiotic and prebiotic treatments can ameliorate dry eye-like symptoms and associated pathological changes in T2DM mice. Moreover, we proved that a high-fat diet and STZ-induced microbiota dysbiosis were involved in diabetic dry eye through the gut-eye axis.

Fecal bacteria transplantation replicates aerobic exercise to reshape the gut microbiota in mice to inhibit high-fat diet-induced atherosclerosis

Aerobic exercise exerts a significant impact on the gut microbiota imbalance and atherosclerosis induced by a high-fat diet. However, whether fecal microbiota transplantation, based on aerobic exercise, can improve atherosclerosis progression remains unexplored. In this study, we utilized male C57 mice to establish models of aerobic exercise and atherosclerosis, followed by fecal microbiota transplantation(Fig 1a). Firstly, we analyzed the body weight, somatotype, adipocyte area, and aortic HE images of the model mice. Our findings revealed that high-fat diet -induced atherosclerosis mice exhibited elevated lipid accumulation, larger adipocyte area, and more severe atherosclerosis progression. Additionally, we assessed plasma lipid levels, inflammatory factors, and gut microbiota composition in each group of mice. high-fat diet -induced atherosclerosis mice displayed dyslipidemia along with inflammatory responses and reduced gut microbiota diversity as well as abundance of beneficial bacteria. Subsequently performing fecal microbiota transplantation demonstrated that high-fat diet -induced atherosclerosis mice experienced weight loss accompanied by reduced lipid accumulation while normalizing their gut microbiota profile; furthermore it significantly improved blood lipids and inflammation markers thereby exhibiting notable anti- atherosclerosis effects. The findings suggest that aerobic exercise can modify gut microbiota composition and improve high-fat diet-induced atherosclerosis(Fig 1b). Moreover, these beneficial effects can be effectively transmitted through fecal microbiota transplantation, offering a promising therapeutic approach for managing atherosclerosis.

Dose-Dependent Effects of Short-Chain Fatty Acids on 3T3-L1 Adipocyte Adipokine Secretion and Metabolic Function

BACKGROUND

Short-chain fatty acids (SCFAs) produced from microbial fermentation of non-digestible carbohydrates and protein have been shown to modulate adipocyte adipokine secretion and metabolic function, which has implications for mitigating dysfunction in obese adipose tissue; however, the individual effects of different SCFAs and the optimal concentration required is unknown. The purpose of this study was to dose-dependently determine the effects of individual SCFAs on adipocyte adipokine secretion and metabolic function.

METHODS

We recapitulated the obese adipocyte inflammatory conditions using mature 3T3-L1 adipocytes and a physiological concentration of lipopolysaccharide (LPS) ± individual SCFAs, namely acetate, propionate, and butyrate, in a dose-dependent manner (0.25 mM, 0.5 mM, and 1 mM) for 24 h.

RESULTS

SCFAs dose-dependently affected inflammatory adipokine secretion, wherein at 1 mM, all three SCFAs reduced the secretion of leptin, IL-6 and IL-1β, but only propionate and butyrate reduced MCP-1/CCL2 and MIP-1α/CCL3 compared to control (p < 0.05). Interestingly, 1 mM acetate increased RANTES/CCL5 secretion versus control, whereas propionate and butyrate decreased RANTES/CCL5 secretion, and only 1 mM propionate reduced MCP-3/CCL7 secretion (p < 0.05). At the lower 0.5 mM concentration, both propionate and butyrate reduced IL-6 and IL-1β secretion compared to control (p < 0.05), and there was no difference in adipokine secretion between groups at the 0.25 mM SCFA concentration (p > 0.05). Intracellular protein expression in the ratio of phosphorylated-to-total STAT3 was reduced by all SCFAs at 1 mM and by propionate and butyrate at 0.5 mM versus control (p < 0.05). The ratio fo phosphorylated-to-total NFκB p65 expression was reduced by propionate and butyrate at 1 mM and by butyrate alone at 0.5 mM compared to control (p < 0.05). Basal (no insulin stimulation) and insulin-stimulated glucose uptake did not differ between control and any 1 mM SCFA treatment conditions (p > 0.05).

CONCLUSIONS

Individual SCFAs exert different dose-dependent effects on LPS-stimulated adipocyte function.

Probiotics alleviate painful diabetic neuropathy by modulating the microbiota-gut-nerve axis in rats

Painful diabetic neuropathy (PDN) is one of the most common complications of diabetes. Recent studies suggested that gut microbiota dysbiosis contributes to the development of PDN, but underlying mechanisms remain elusive. In this study, we found decreased probiotics generating bacteria such as Lactobacillus and Bifidobacterium strains in the PDN rats. Supplementation with multiple probiotics for 12 weeks alleviated pain, reversed nerve fiber lesions, and restored neuronal hyperexcitability. Probiotics administration effectively attenuated intestinal barrier impairment, reduced serum lipopolysaccharide and proinflammatory cytokines, and mitigated disruptions in the blood-nerve barrier. Furthermore, probiotics treatment inhibited the activation of the TLR4/MyD88/NF-κB signaling pathway and reduced proinflammatory cytokines in the sciatic nerve of the PDN rats. Together, our findings suggest that gut microbiota dysbiosis participates in PDN pathogenesis, and probiotics offer therapeutic potential via modulating the microbiota-gut-nerve axis.

The role of reproductive tract microbiota in gynecological health and diseases

The reproductive tract, as a lumen connected to the outside world, its microbial community is influenced by various factors. The changes in its microbiome are closely related to women's health. The destruction of the micro ecological environment will lead to various infections, such as Bacterial vaginosis, sexually transmitted infections, adverse pregnancy outcomes, infertility and tumors. In recent years, with the continuous development and progress of molecular biology, research on reproductive tract microbiota has become a clinical hotspot. The reproductive tract microbiota is closely related to the occurrence and development of female reproductive tract diseases such as vaginitis, pelvic inflammation, PCOS, cervical lesions, and malignant tumors. This article reviews the research on the relationship between vaginal microbiota and female reproductive tract diseases, in order to provide theoretical basis for the prevention and treatment of female reproductive tract diseases.

Gut microbiome and body composition with sorbitol intake during early lifespan

OBJECTIVE

The association of sorbitol intake with maintaining healthy body weight through the gut microbiome during early life was investigated.

RESEARCH METHODS AND PROCEDURES

Sorbitol intake, body mass index (BMI), and fecal samples were collected in the total of 369 pregnant women with their infants (aged 4 months to 5 years) from the Taipei Mother-Infant Nutrition Cohort and 1946 children and adolescents (aged 6-18 years) from the Taiwan Puberty Longitudinal Study. The BMI-z score in sorbitol users was compared to that in sorbitol nonusers using generalized linear mixed model. The beta diversity of microbiome was investigated in both cohorts. The association between the richness of microbes and body composition was analyzed.

RESULTS

The children and adolescents with high sorbitol intake had lower BMI-z score at 6 to 10 and 11 to 18 years of age (P < 0.01) compared with those without sorbitol intake. The beta diversity of the microbiome differed significantly between the sorbitol users and nonusers. Bifidobacterium was higher in the gut of infants and children whose mothers were sorbitol users than that of infants and children whose mothers were sorbitol nonusers during pregnancy. Several microbes were involved in the regulation of obesity, such as Staphylococcus, Faecalibacterium, and Oscillospiraceae_UCG-005 negatively associated with anthropometric measures.

CONCLUSIONS

Sorbitol intake was associated with lower child and adolescent BMI. Sorbitol consumption could shape the composition and richness of beneficial microbiota, contributing to the maintenance of ideal body weight and metabolic homeostasis in early life.

The gut microbiota in thrombosis

The gut microbiota has emerged as an environmental risk factor that affects thrombotic phenotypes in several cardiovascular diseases. Evidence includes the identification of marker species by sequencing studies of the gut microbiomes of patients with thrombotic disease, the influence of antithrombotic therapies on gut microbial diversity, and preclinical studies in mouse models of thrombosis that have demonstrated the functional effects of the gut microbiota on vascular inflammatory phenotypes and thrombus formation. In addition to impaired gut barrier function promoting low-grade inflammation, gut microbiota-derived metabolites have been shown to act on vascular cell types and promote thrombus formation. Therefore, these meta-organismal pathways that link the metabolic capacities of gut microorganisms with host immune functions have emerged as potential diagnostic markers and novel drug targets. In this Review, we discuss the link between the gut microbiota, its metabolites and thromboembolic diseases.

Biomimetic nanoplatform with microbiome modulation and antioxidant functions ameliorating insulin resistance and pancreatic β-cell dysfunction for T2DM management

Insulin resistance and pancreatic β-cell dysfunction are the main pathogenesis of type 2 diabetes mellitus (T2DM). However, insulin therapy and diabetes medications do not effectively solve the two problems simultaneously. In this study, a biomimetic oral hydrogen nanogenerator that leverages the benefits of edible plant-derived exosomes and hydrogen therapy was constructed to overcome this dilemma by modulating gut microbiota and ameliorating oxidative stress and inflammatory responses. Hollow mesoporous silica (HMS) nanoparticles encapsulating ammonia borane (A) were used to overcome the inefficiency of H2 delivery in traditional hydrogen therapy, and exosomes originating from ginger (GE) were employed to enhance biocompatibility and regulate intestinal flora. Our study showed that HMS/A@GE not only considerably ameliorated insulin resistance and liver steatosis, but inhibited the dedifferentiation of islet β-cell and enhanced pancreatic β-cell proportion in T2DM model mice. In addition to its antioxidant and anti-inflammatory effects, HMS/A@GE augmented the abundance of Lactobacilli spp. and tryptophan metabolites, such as indole and indole acetic acid, which further activated the AhR/IL-22 pathway to improve intestinal-barrier function and metabolic impairments. This study offers a potentially viable strategy for addressing the current limitations of diabetes treatment by integrating gut-microbiota remodelling with antioxidant therapies.

GLP-1 and IL-6 regulates obesity in the gut and brain

Obesity is a chronic metabolic disease characterized by excessive nutrient intake leading to increased subcutaneous or visceral fat, resulting in pathological and physiological changes. The incidence rate of obesity, an important form of metabolic syndrome, is increasing worldwide. Excess appetite is a key pathogenesis of obesity, and the inflammatory response induced by obesity has received increasing attention. This review focuses on the role of appetite-regulating factor (Glucogan-like peptide 1) and inflammatory factor (Interleukin-6) in the gut and brain in individuals with obesity and draws insights from the current literature.

Saturated fat in an evolutionary context

Evolutionary perspectives have yielded profound insights in health and medical sciences. A fundamental recognition is that modern diet and lifestyle practices are mismatched with the human physiological constitution, shaped over eons in response to environmental selective pressures. This Darwinian angle can help illuminate and resolve issues in nutrition, including the contentious issue of fat consumption. In the present paper, the intake of saturated fat in ancestral and contemporary dietary settings is discussed. It is shown that while saturated fatty acids have been consumed by human ancestors across time and space, they do not feature dominantly in the diets of hunter-gatherers or projected nutritional inputs of genetic accommodation. A higher intake of high-fat dairy and meat products produces a divergent fatty acid profile that can increase the risk of cardiovascular and inflammatory disease and decrease the overall satiating-, antioxidant-, and nutrient capacity of the diet. By prioritizing fiber-rich and micronutrient-dense foods, as well as items with a higher proportion of unsaturated fatty acids, and in particular the long-chain polyunsaturated omega-3 fatty acids, a nutritional profile that is better aligned with that of wild and natural diets is achieved. This would help prevent the burdening diseases of civilization, including heart disease, cancer, and neurodegenerative conditions. Saturated fat is a natural part of a balanced diet; however, caution is warranted in a food environment that differs markedly from the one to which we are adapted.

Akkermansia muciniphila supplementation in patients with overweight/obese type 2 diabetes: Efficacy depends on its baseline levels in the gut

Akkermansia muciniphila is a promising target for managing obesity and type 2 diabetes (T2D), but human studies are limited. We conducted a 12-week randomized, double-blind, placebo-controlled trial involving 58 participants with overweight or obese T2D, who received A. muciniphila (AKK-WST01) or placebo, along with routine lifestyle guidance. Both groups showed decreases in body weight and glycated hemoglobin (HbA1c), without significant between-group differences. In participants with low baseline A. muciniphila, AKK-WST01 supplementation showed high colonization efficiency and significant reductions in body weight, fat mass, and HbA1c, which were not found in the placebo group. However, AKK-WST01 supplementation showed poor colonization and no significant clinical improvements in participants with high baseline A. muciniphila. These findings were verified in germ-free mice receiving feces with low or high A. muciniphila. Our study indicates that metabolic benefits of A. muciniphila supplementation could depend on its baseline intestinal levels, supporting the potential for gut microbiota-guided probiotic supplementation. (ClinicalTrials.gov number, NCT04797442).

Gut Microbial Changes Associated With Obesity in Youth With Type 1 Diabetes

CONTEXT

Obesity is prevalent in type 1 diabetes (T1D) and is problematic with higher risk for diabetes complications. It is unknown to what extent gut microbiome changes are associated with obesity and T1D.

OBJECTIVE

This work aimed to describe the gut microbiome and microbial metabolite changes associated with obesity in T1D. We hypothesized statistically significant gut microbial and metabolite differences in lean T1D youth (body mass index [BMI]: 5%-<85%) vs those with obesity (BMI: ≥95%).

METHODS

We analyzed stool samples for gut microbial (using metagenomic shotgun sequencing) and short-chain fatty acid (SCFA) differences in lean (n = 27) and obese (n = 21) T1D youth in a pilot study. The mean ± SD age was 15.3 ± 2.2 years, glycated hemoglobin A1c 7.8 ± 1.3%, diabetes duration 5.1 ± 4.4 years, 42.0% female, and 94.0% were White.

RESULTS

Bacterial community composition showed between sample diversity differences (β-diversity) by BMI group (P = .013). There was a higher ratio of Prevotella to Bacteroides in the obese group (P = .0058). There was a differential distribution of significantly abundant taxa in either the lean or obese groups, including increased relative abundance of Prevotella copri, among other taxa in the obese group. Functional profiling showed an upregulation of branched-chain amino acid (BCAA) biosynthesis in the obese group and upregulation of BCAA degradation, tyrosine metabolism, and secondary bile acid biosynthesis in the lean group. Stool SCFAs were higher in the obese vs the lean group (P < .05 for all).

CONCLUSION

Our findings identify a gut microbiome and microbial metabolite signature associated with obesity in T1D. These findings could help identify gut microbiome-targeted therapies to manage obesity in T1D.

A disturbed communication between hypothalamic-pituitary-ovary axis and gut microbiota in female infertility: is diet to blame?

Female infertility is a multifactorial condition influenced by various genetic, environmental, and lifestyle factors. Recent research has investigated the significant impact of gut microbiome dysbiosis on systemic inflammation, metabolic dysfunction, and hormonal imbalances, which can potentially impair fertility. The gut-brain axis, a bidirectional communication system between the gut and the brain, also plays a significant role in regulating reproductive functions. Emerging evidence suggests that the gut microbiome can influence brain functions and behavior, further emphasizing the importance of the microbiota-gut-brain axis in reproduction. Given their role as a major modulator of the gut microbiome, diet and dietary factors, including dietary patterns and nutrient intake, have been implicated in the development and management of female infertility. Hence, this review aims to highlight the impact of dietary patterns, such as the Western diet (WD) and Mediterranean diet (MD), and to decipher their modulatory action on the microbiota-gut-brain axis in infertile women. By contrasting the detrimental effects of WD with the therapeutic potential of MD, we emphasize the pivotal role of a balanced diet rich in nutrients in promoting a healthy gut microbiome. These insights underscore the potential of targeted dietary interventions and lifestyle modifications as promising strategies to enhance reproductive outcomes in subfertile women.

Fucoidan Oligosaccharide Supplementation Relieved Kidney Injury and Modulated Intestinal Homeostasis in D-Galactose-Exposed Rats

Background/Objectives: A fucoidan oligosaccharide (FOS), a potent compound derived from algae, is known for its diverse biological activities, including prebiotic activity, anticancer activity, and antioxidative properties, and has demonstrated supportive therapeutic effects in treating kidney ailments. This study was conducted to explore the protective influence of FOS on kidney damage due to aging induced by D-galactose in Sprague Dawley (SD) rats. Methods: The low-dose FOS group was administered FOS (100 mg/kg) by gavage, and the high-FOS group received FOS (200 mg/kg) by gavage. Results: The findings showed that FOS could effectively mitigate kidney damage and improve the pathological condition of kidney tissues caused by D-gal and enhance kidney function. Intervention with FOS significantly reduced serum creatinine, serum uric acid, and serum urea nitrogen levels, compared to the model group. The protective mechanism of FOS on D-gal-induced kidney injury may be to inhibit oxidative stress and improve impaired mitochondrial function by downregulating the AMPK/ULK1 signaling pathway. FOS could also modulate the expression of mitochondrial autophagy-related proteins (Beclin-1, P62, and LC3II/LC3I), thereby mitigate D-gal-induced excessive mitophagy in the kidney. Furthermore, FOS may protect against kidney injury by preserving intestinal homeostasis. FOS decreased serum lipopolysaccharide levels and enhanced intestinal mucosal barrier function. FOS upregulated the abundances of Bacteroidota, Muribaculaceae, and Lactobacillus, while it decreased the abundances of Firmicutes, NK4A136_group, and Lachnospiraceae_NK4A136_group. FOS supplementation modulated gut microbiota composition, increasing beneficial bacteria and reducing detrimental ones, potentially contributing to improved kidney function. Conclusions: FOS may safeguard against renal injury in D-gal-exposed rats by inhibiting kidney excessive mitophagy, preserving mitochondrial function, and regulating intestinal homeostasis.

Multiomics of the intestine-liver-adipose axis in multiple studies unveils a consistent link of the gut microbiota and the antiviral response with systemic glucose metabolism

BACKGROUND

The microbiota is emerging as a key factor in the predisposition to insulin resistance and obesity.

OBJECTIVE

To understand the interplay among gut microbiota and insulin sensitivity in multiple tissues.

DESIGN

Integrative multiomics and multitissue approach across six studies, combining euglycaemic clamp measurements (used in four of the six studies) with other measurements of glucose metabolism and insulin resistance (glycated haemoglobin (HbA1c) and fasting glucose).

RESULTS

Several genera and species from the Proteobacteria phylum were consistently negatively associated with insulin sensitivity in four studies (ADIPOINST, n=15; IRONMET, n=121, FLORINASH, n=67 and FLOROMIDIA, n=24). Transcriptomic analysis of the jejunum, ileum and colon revealed T cell-related signatures positively linked to insulin sensitivity. Proteobacteria in the ileum and colon were positively associated with HbA1c but negatively with the number of T cells. Jejunal deoxycholic acid was negatively associated with insulin sensitivity. Transcriptomics of subcutaneous adipose tissue (ADIPOMIT, n=740) and visceral adipose tissue (VAT) (ADIPOINST, n=29) revealed T cell-related signatures linked to HbA1c and insulin sensitivity, respectively. VAT Proteobacteria were negatively associated with insulin sensitivity. Multiomics and multitissue integration in the ADIPOINST and FLORINASH studies linked faecal Proteobacteria with jejunal and liver deoxycholic acid, as well as jejunal, VAT and liver transcriptomic signatures involved in the actin cytoskeleton, insulin and T cell signalling. Fasting glucose was consistently linked to interferon-induced genes and antiviral responses in the intestine and VAT. Studies in Drosophila melanogaster validated these human insulin sensitivity-associated changes.

CONCLUSION

These data provide comprehensive insights into the microbiome-gut-adipose-liver axis and its impact on systemic insulin action, suggesting potential therapeutic targets.Cite Now.

Malnutrition and Its Influence on Gut sIgA-Microbiota Dynamics

In the current era, malnutrition is seen as both undernutrition and overweight and obesity; both conditions are caused by nutrient deficiency or excess and improper use or imbalance in the intake of macro and micronutrients. Recent evidence suggests that malnutrition alters the intestinal microbiota, known as dysbiosis. Secretory immunoglobulin A (sIgA) plays an important role in maintaining and increasing beneficial intestinal microbiota populations and protecting against pathogenic species. Depletion of beneficial bacterial populations throughout life is also conditioned by malnutrition. This review aims to synthesize the evidence that establishes an interrelationship between diet, malnutrition, changes in the intestinal flora, and sIgA levels. Targeted nutritional therapies combined with prebiotic, probiotic, and postbiotic administration can restore the immune response in the intestine and the host's homeostasis.

Postbiotic Impact on Host Metabolism and Immunity Provides Therapeutic Potential in Metabolic Disease

The gut microbiota influences aspects of metabolic disease, including tissue inflammation, adiposity, blood glucose, insulin, and endocrine control of metabolism. Prebiotics or probiotics are often sought to combat metabolic disease. However, prebiotics lack specificity and can have deleterious bacterial community effects. Probiotics require live bacteria to find a colonization niche sufficient to influence host immunity or metabolism. Postbiotics encompass bacterial-derived components and molecules, which are well-positioned to alter host immunometabolism without relying on colonization efficiency or causing widespread effects on the existing microbiota. Here, we summarize the potential for beneficial and detrimental effects of specific postbiotics related to metabolic disease and the underlying mechanisms of action. Bacterial cell wall components, such as lipopolysaccharides, muropeptides, lipoteichoic acids and flagellin, have context-dependent effects on host metabolism by engaging specific immune responses. Specific types of postbiotics within broad classes of compounds, such as lipopolysaccharides and muropeptides, can have opposing effects on endocrine control of host metabolism, where certain postbiotics are insulin sensitizers and others promote insulin resistance. Bacterial metabolites, such as short-chain fatty acids, bile acids, lactate, glycerol, succinate, ethanolamine, and ethanol, can be substrates for host metabolism. Postbiotics can fuel host metabolic pathways directly or influence endocrine control of metabolism through immunomodulation or mimicking host-derived hormones. The interaction of postbiotics in the host-microbe relationship should be considered during metabolic inflammation and metabolic disease.

The oral-gut microbiota axis: a link in cardiometabolic diseases

The oral-gut microbiota axis plays a crucial role in cardiometabolic health. This review explores the interactions between these microbiomes through enteric, hematogenous, and immune pathways, resulting in disruptions in microbial balance and metabolic processes. These disruptions contribute to systemic inflammation, metabolic disorders, and endothelial dysfunction, which are closely associated with cardiometabolic diseases. Understanding these interactions provides insights for innovative therapeutic strategies to prevent and manage cardiometabolic diseases.

From Endoscopic Inspection to Gene-Expression: A Thorough Assessment of the Duodenal Mucosa After Resurfacing-A Prospective Study

AIMS

Duodenal Mucosal Resurfacing (DMR) is an endoscopic ablation technique aimed at improving glycemia in patients with type 2 diabetes mellitus (T2DM). Although the exact underlying mechanism is still unclear, it is postulated that the DMR-induced improvements are the result of changes in the duodenal mucosa. For this reason, we assessed macroscopic and microscopic changes in the duodenal mucosa induced by DMR + GLP-1RA.

METHODS

We included 16 patients with T2DM using basal insulin that received a combination treatment of a single DMR and GLP-1RA. Endoscopic evaluation was performed before the DMR procedure and 3 month after, and duodenal biopsies were obtained. Histological evaluation was performed and L and K cell density was calculated. In addition, gene-expression analysis and Western blotting was performed.

RESULTS

Endoscopic evaluation at 3 month showed duodenal mucosa with a normal appearance. In line, microscopic histological evaluation showed no signs of villous atrophy or inflammation and unchanged L and K cell density. Unbiased transcriptome profiling and western blotting revealed that PDZK1 expression was higher in responders at baseline and after DMR. GATA6 expression was significantly increased in responders after DMR compared to non-responders.

CONCLUSION

The absence of macroscopic and microscopic changes after 3 month suggest that improvements in glycemic parameters after DMR do not result from significant histological changes in duodenal mucosa. It is more likely that these improvements result from more subtle changes in enteroendocrine signaling. PDZK1 and GATA6 expression might play a role in DMR; this needs to be confirmed in pre-clinical studies.

The Gut Microbiota-Related Antihyperglycemic Effect of Metformin

It is critical to sustain the diversity of the microbiota to maintain host homeostasis and health. Growing evidence indicates that changes in gut microbial biodiversity may be associated with the development of several pathologies, including type 2 diabetes mellitus (T2DM). Metformin is still the first-line drug for treatment of T2DM unless there are contra-indications. The drug primarily inhibits hepatic gluconeogenesis and increases the sensitivity of target cells (hepatocytes, adipocytes and myocytes) to insulin; however, increasing evidence suggests that it may also influence the gut. As T2DM patients exhibit gut dysbiosis, the intestinal microbiome has gained interest as a key target for metabolic diseases. Interestingly, changes in the gut microbiome were also observed in T2DM patients treated with metformin compared to those who were not. Therefore, the aim of this review is to present the current state of knowledge regarding the association of the gut microbiome with the antihyperglycemic effect of metformin. Numerous studies indicate that the reduction in glucose concentration observed in T2DM patients treated with metformin is due in part to changes in the biodiversity of the gut microbiota. These changes contribute to improved intestinal barrier integrity, increased production of short-chain fatty acids (SCFAs), regulation of bile acid metabolism, and enhanced glucose absorption. Therefore, in addition to the well-recognized reduction of gluconeogenesis, metformin also appears to exert its glucose-lowering effect by influencing gut microbiome biodiversity. However, we are only beginning to understand how metformin acts on specific microorganisms in the intestine, and further research is needed to understand its role in regulating glucose metabolism, including the impact of this remarkable drug on specific microorganisms in the gut.

Modulation of gut microbiota, up-regulation of ZO-1, and promotion of metabolism as therapeutic mechanisms of indole-3-carbinol against obesity in mice

Background

Indole-3-carbinol (I3C) is a compound derived from Cruciferous vegetables. We aim to ascertain whether I3C mediates the relations between mouse gut microbiota, intestinal barrier function, and metabolism to treat obesity in mice.

Methods

The experimental analyses focused on the changes in lipid distribution, inflammatory cytokines, glucose tolerance, gut microbiota composition, and serum metabolomics of 60 C57BL/6N mice.

Results

The experimental results demonstrated that I3C reduced body weight, hepatic steatosis, and systemic inflammation and improved insulin resistance in mice on a high-fat diet (HFD). Furthermore, I3C remarkably enhanced the enrichment of probiotics Akkermansia and Ligilactobacillus as well as SCFA-producing bacteria (Eubacterium, Lactococcus, and Coprococcus), while reducing the abundance of Eisenbergiella and Rikenellaceae_RC9_gut_group. Also, I3C notably up-regulated the levels of Claudin4, Occludin, and ZO-1 proteins and modulated the metabolism of argininosuccinic acid and galactose.

Conclusion

The aforementioned findings suggest that I3C exerts a significant anti-obesity effect in mice by regulating abnormal gut microbiome, enhancing intestinal barrier function, and improving metabolic disorders.

Identifying the Involvement of Gut Microbiota in Retinal Vein Occlusion by Mendelian Randomization and Genetic Correlation Analysis

Purpose

Previous researches have suggested an important association between gut microbiota (GM) and vascular pathologies such as atherosclerosis. This study aimed to explore the association between 196 GM taxa and retinal vein occlusion (RVO).

Methods

This study used Mendelian randomization (MR), linkage disequilibrium score regression (LDSC), and polygenic overlap analysis. Genome-wide association study (GWAS) data associated with 196 GM taxa was obtained from the MiBioGen consortium, involving a large number of European-ancestry participants. GWAS data of RVO was obtained from the FinnGen consortium and another study that also involved European-ancestry participants. Inverse-variance weighted was used as the primary approach for MR estimation. Moreover, LDSC and polygenic overlap analyses were performed to evaluate the genetic correlation between GM taxa and RVO.

Results

The MR results identified the association of six GM taxa, including class Bacilli, order Lactobacillales, family Streptococcaceae, genus Clostridium innocuum group, genus Family XIII AD3011 group, and genus Subdoligranulum with the development of RVO. In addition, the polygenic overlap analysis supported the genetic association between GM and RVO.

Conclusions

Our findings confirmed the association between six GM taxa and the development of RVO, thereby highlighting the effects of GM on retinal vascular health.

Translational Relevance

The results may provide the rationale for developing GM-based strategies for preventing the onset of RVO.

Dietary ω-3 Fatty Acids Mitigate Intestinal Barrier Integrity Alterations in Mice Fed a High-Fat Diet: Implications for Pancreatic Carcinogenesis

BACKGROUND

Although body fatness is a recognized risk factor for pancreatic ductal adenocarcinoma (PDAC), the underlying mechanisms of how fat composition affects pancreatic carcinogenesis are poorly understood. High-fat diets (HFDs) can disrupt intestinal barrier function, potentially accelerating carcinogenesis. Omega-3 (ω-3) polyunsaturated fatty acids (FAs) have anti-inflammatory properties and help preserve intestinal integrity.

OBJECTIVE

The objective of this study was to evaluate how ω-3 FAs affect the colonic barrier in the context of HFD-induced changes, in a mouse model of PDAC [p48-Cre; LSL-KrasG12D (KC)].

METHODS

Male and female KC mice were randomly assigned into 1 of the following 4 groups: 1) a control diet containing ∼11% total calories from fat with an ω-6:ω-3 FA ratio of 10:1 (C), 2) the control diet with high concentrations of ω-3 FA with an ω-6:ω-3 FA ratio of 1:1 (Cω3), 3) an HFD containing 60% total calories from fat with an ω-6:ω-3 FA ratio of approximately 10:1 (HF), and 4) an HFD with high concentrations of ω-3 FA with an ω-6:ω-3 FA ratio of 1:1 (HFω3).

RESULTS

Consumption of an HFD for 8 wk caused: 1) disruption of tight junction structure and function; 2) decreased goblet cell number; 3) higher colonic Toll-like receptor 4 (TLR4) and NADPH oxidase 1 expression; 4) activation of TLR4-triggered pathways, that is, NF-κB, c-Jun N-terminal kinase; 5) elevated plasma lipopolysaccharide concentrations; and 6) higher pancreatic TLR4 expression, and 7) accelerated acinar-to-ductal metaplasia. All of these events were mitigated in mice fed the HFω3.

CONCLUSIONS

Our findings support the concept that, in the context of obesity, ω-3 FAs have protective effects during early-stage pancreatic carcinogenesis through the regulation of intestinal permeability and endotoxemia.

Natural Products and Diabetes: (-)-Epicatechin and Mechanisms Involved in the Regulation of Insulin Sensitivity

Type 2 diabetes (T2D) is a disease that occurs when cells do not respond normally to insulin, a condition called insulin resistance, which leads to high blood glucose levels. Although it can be treated pharmacologically, dietary habits beyond carbohydrate restriction can be highly relevant in the management of T2D. Emerging evidence supports the possibility that natural products (NPs) could contribute to managing blood glucose or counteract the undesirable effects of hyperglycemia and insulin resistance. This chapter summarizes the relevant preclinical evidence involving the flavonoid (-)-epicatechin (EC) in the optimization of glucose homeostasis, reducing insulin resistance and/or diabetes-associated disorders. Major effects of EC are observed on (i) intestinal functions, including digestive enzymes, glucose transporters, microbiota, and intestinal permeability, and (ii) redox homeostasis, including oxidative stress and inflammation. There is still a need for further clinical studies to confirm the in vitro and rodent data, allowing recommendations for EC, particularly in prediabetic and T2D patients. The collection of similar data and the lack of clinical evidence for EC is also applicable to other NPs.

Chylomicron Characteristics Are Associated With Microsomal Triglyceride Transfer Protein in an Animal Model of Diet-Induced Dysbiosis

Objective

Intestinal remnant chylomicrons (CMs) are involved in cardiovascular residual risk and the atherogenic process. Microsomal triglyceride transfer protein (MTTP) catalyzes the assembly of lipids to apolipoprotein B48, generating CMs. Dysbiosis could alter this behavior. This study investigated the chemical composition of CMs and their associations with intestinal MTTP and gut fat depots in a diet-induced dysbiosis animal model.

Methods

Male Wistar rats were fed either a standard diet (control, n=10) or a high-fat high-sucrose diet (HFSD, n=10) for 14 weeks. Measurements included serum glucose, lipid-lipoprotein profile, free fatty acids (FFAs), lipopolysaccharide (LPS) and the Firmicutes/Bacteroidetes (F/B) ratio in stool samples, via real-time quantitative polymerase chain reaction. Lipid content in isolated CMs (ultracentrifugation d <0.95 g/mL) was assessed, and MTTP, cell intestinal fat content (CIF), histology, apoB mRNA and tight junction (TJ) proteins were analyzed, in intestinal tissue.

Results

Compared to control, HFSD rats showed higher levels of LPS, triglycerides (TGs), non-high-density lipoprotein cholesterol (HDL-C) levels, TG/HDL-C ratio, FFAs, and the F/B ratio. HFSD CMs showed increased TG and phospholipids. TJ proteins levels were lower in the HFSD group, while histological scores showed no differences. CIF was increased in the HFSD group. No significant differences in apoB mRNA were found. MTTP expression was higher in the HFSD group, and directly correlated with CM-TG and inversely correlated with CIF.

Conclusion

Our findings imply that gut TG content may constitute an important determinant of the secretion of TG-rich CMs, promoted by MTTP, with increased atherogenic potential.

The Role of the Neural Exposome as a Novel Strategy to Identify and Mitigate Health Inequities in Alzheimer's Disease and Related Dementias

With the continuous increase of the elderly population, there is an urgency to understand and develop relevant treatments for Alzheimer's disease and related dementias (ADRD). In tandem with this, the prevalence of health inequities continues to rise as disadvantaged communities fail to be included in mainstream research. The neural exposome poses as a relevant mechanistic approach and tool for investigating ADRD onset, progression, and pathology as it accounts for several different factors: exogenous, endogenous, and behavioral. Consequently, through the neural exposome, health inequities can be addressed in ADRD research. In this paper, we address how the neural exposome relates to ADRD by contributing to the discourse through defining how the neural exposome can be developed as a tool in accordance with machine learning. Through this, machine learning can allow for developing a greater insight into the application of transferring and making sense of experimental mouse models exposed to health inequities and potentially relate it to humans. The overall goal moving beyond this paper is to define a multitude of potential factors that can increase the risk of ADRD onset and integrate them to create an interdisciplinary approach to the study of ADRD and subsequently translate the findings to clinical research.

Targeting the NLRP3 inflammasome-IL-1β pathway in type 2 diabetes and obesity

Increased activity of the NACHT, LRR and PYD domains-containing protein 3 (NLRP3) inflammasome-IL-1β pathway is observed in obesity and contributes to the development of type 2 diabetes and its complications. In this review, we describe the pathological activation of IL-1β by metabolic stress, ageing and the microbiome and present data on the role of IL-1β in metabolism. We explore the physiological role of the IL-1β pathway in insulin secretion and the relationship between circulating levels of IL-1β and the development of diabetes and associated diseases. We highlight the paradoxical nature of IL-1β as both a friend and a foe in glucose regulation and provide details on clinical translation, including the glucose-lowering effects of IL-1 antagonism and its impact on disease modification. We also discuss the potential role of IL-1β in obesity, Alzheimer's disease, fatigue, gonadal dysfunction and related disorders such as rheumatoid arthritis and gout. Finally, we address the safety of NLRP3 inhibition and IL-1 antagonists and the prospect of using this therapeutic approach for the treatment of type 2 diabetes and its comorbidities.

Rebalancing immune homeostasis in combating disease: The impact of medicine food homology plants and gut microbiome

BACKGROUND

Gut microbiota plays an important role in multiple human physiological processes and an imbalance in it, including the species, abundance, and metabolites can lead to diseases. These enteric microorganisms modulate immune homeostasis by presenting a myriad of antigenic determinants and microbial metabolites. Medicinal and food homologous (MFH) plants, edible herbal materials for both medicine and food, are important parts of Traditional Chinese Medicine (TCM). MFH plants have drawn much attention due to their strong biological activity and low toxicity. However, the interplay of MFH and gut microbiota in rebalancing the immune homeostasis in combating diseases needs systematic illumination.

PURPOSE

The review discusses the interaction between MFH and gut microbiota, including the effect of MFH on the major group of gut microbiota and the metabolic effect of gut microbiota on MFH. Moreover, how gut microbiota influences the immune system in terms of innate and adaptive immunity is addressed. Finally, the immunoregulatory mechanisms of MFH in regulation of host pathophysiology via gut microbiota are summarized.

METHODS

Literature was searched, analyzed, and collected using databases, including PubMed, Web of Science, and Google Scholar using relevant keywords. The obtained articles were screened and summarized by the research content of MFH and gut microbiota in immune regulation.

RESULTS

The review demonstrates the interaction between MFH and gut microbiota in disease prevention and treatment. Not only do the intestinal microorganisms and intestinal mucosa constitute an important immune barrier of the human body, but also lymphoid tissue and diffused immune cells within the mucosa participate in the response of innate immunity and adaptive immunity. MFH modulates immune regulation by affecting intestinal flora, helps maintain the balance of the immune system and interfere with the occurrence and development of a broad category of diseases.

CONCLUSION

Being absorbed from the gastrointestinal tract, MFH can have profound effects on gut microbiota. In turn, the gut microbiota also actively participate in the bioconversion of complex constituents from MFH, which could further influence their physiological and pharmacological properties. The review deepens the understanding of the relationship among MFH, gut microbiota, immune system, and human diseases and further promotes the progression of additional relevant research.