Gut microbiota confers host resistance to obesity by metabolizing dietary polyunsaturated fatty acids. Nat Commun. 2019;10:4007. [PMID: 31488836 PMCID: PMC6728375 DOI: 10.1038/s41467-019-11978-0]

Dietary polyunsaturated fatty acids intake is negatively associated with hyperuricemia: The National Health and Nutrition Examination Survey 2003-2015

BACKGROUND AND AIMS

The objective of this research was to explore the associations between dietary PUFAs intake and hyperuricemia risk.

METHODS AND RESULTS

Based on the National Health and Nutrition Examination Survey (NHANES) 2003-2015, all eligible individuals were divided into hyperuricemia and non-hyperuricemia groups based on diagnostic criteria for hyperuricemia (serum uric acid >420 μmol/L for men and >360 μmol/L for women). Multivariate-adjusted logistic regression was employed to explore the relationship between dietary PUFAs intake and hyperuricemia risk. Total PUFAs and their subtypes were modeled to isocalorically replace saturated fatty acids (SFAs) and monounsaturated fatty acids (MUFAs). Higher intake of n-3 PUFAs, n-6 PUFAs, linoleic acid (LA), alpha-linoleic acid (ALA), and non-marine PUFAs intake correlated with decreased hyperuricemia risk, with adjusted odds ratio (OR) and 95% confidence interval (95%CIs) were 0.77 (0.63, 0.93), 0.75 (0.61, 0.92), 0.75 (0.61, 0.91), 0.69 (0.55, 0.87), and 0.73 (0.59, 0.91), respectively. Replacing 5% of total energy intake from SFAs with isocaloric PUFAs was associated with decreased odds of hyperuricemia in men (0.69 (0.57, 0.84)) and in individuals (0.81 (0.71, 0.92)). Similar trends were observed in the substitution of SFAs with non-marine PUFAs in men (0.87 (0.80, 0.94)) and in all individuals (0.92 (0.88, 0.98)). Sensitivity analyses exhibited consistent results with primary analyses.

CONCLUSION

Higher dietary intake of n-3 PUFAs, n-6 PUFAs, LA, ALA, and non-marine PUFAs was associated with decreased hyperuricemia risk. These results support the recommendation to substitute SFAs with PUFAs in diet.

Obesity and the gut microbiota: implications of neuroendocrine and immune signaling

Obesity is a major health challenge due to its high prevalence and associated comorbidities. The excessive intake of a diet rich in fat and sugars leads to a persistent imbalance between energy intake and energy expenditure, which increases adiposity. Here, we provide an update on relevant diet-microbe-host interactions contributing to or protecting from obesity. In particular, we focus on how unhealthy diets shape the gut microbiota and thus impact crucial intestinal neuroendocrine and immune system functions. We describe how these interactions promote dysfunction in gut-to-brain neuroendocrine pathways involved in food intake control and postprandial metabolism and elevate the intestinal proinflammatory tone, promoting obesity and metabolic complications. In addition, we provide examples of how this knowledge may inspire microbiome-based interventions, such as fecal microbiota transplants, probiotics, and biotherapeutics, to effectively combat obesity-related disorders. We also discuss the current limitations and gaps in knowledge of gut microbiota research in obesity.

Interactions between lipid metabolism and the microbiome in aquatic organisms: A review

Marine organisms' lipid metabolism contributes to marine ecosystems by producing a variety of lipid molecules. Historically, research focused on the lipid metabolism of the organisms themselves. Recent microbiome studies, however, have revealed that gut microbial communities influence the amount and type of lipids absorbed by organisms, thereby altering the organism's lipid metabolism. This has highlighted the growing importance of research on gut microbiota. This review highlights mechanisms by which gut microbiota facilitate lipid digestion and diversify the lipid pool in aquatic animals through the accelerated degradation of exogenous lipids and the transformation of lipid molecules. We also assess how environmental factors and pollutants, along with the innovative use of probiotics, interact with the gut microbiome to influence lipid metabolism within the host. We aim to elucidate the complex interactions between lipid metabolism and gut microbiota in aquatic animals by synthesizing current research and identifying knowledge gaps, providing a foundation for future explorations.

Indole-3-aldehyde Alleviates High-Fat Diet-Induced Gut Barrier Disruption by Increasing Intestinal Stem Cell Expansion

High-fat diet (HFD) feeding is known to cause intestinal barrier disruption, thereby triggering severe intestinal inflammatory disease. Indole-3-aldehyde (IAld) has emerged as a potential candidate for mitigating inflammatory responses and maintaining intestinal homeostasis. However, the role of IAld in the HFD-related intestinal disruption remains unclear. In this study, 48 7 week-old male C57BL/6J mice were assigned to four groups: the normal chow diet (NCD) group received a NCD; the HFD group was fed an HFD; the HFD + IAld200 group was supplemented with 200 mg/kg IAld in the HFD; and the HFD + IAld600 group was supplemented with 600 mg/kg IAld in the HFD. The results showed that dietary IAld supplementation ameliorated fat accumulation and metabolic disorders, which are associated with reduced intestinal permeability. This reduction potentially led to decreased systemic inflammation and enhanced intestinal barrier function in HFD-fed mice. Furthermore, we found that IAld promoted intestinal stem cell (ISC) proliferation by activating aryl hydrocarbon receptors (AHRs) in vivo and ex vivo. These findings suggest that IAld restores the HFD-induced intestinal barrier disruption by promoting AHR-mediated ISC proliferation.

Rapid Analysis of Colonic Metabolomics in High-Fat Diet Mice by Extraction Electrospray Ionization Mass Spectrometry (EESI-MS)

Propolis exhibits significant anti-inflammatory, antidiabetic, and antiobesity properties in both mouse models and clinical applications. However, the underlying metabolic mechanisms remain poorly understood. Traditional metabolomic methods that rely on chromatographic separation require complex preprocessing steps and extended detection periods. In this study, we employed extraction electrospray ionization mass spectrometry combined with multivariate analysis to directly profile metabolites in the colon tissue of mice. Our findings demonstrate the efficacy of ethanol extract of propolis (EEP) in mitigating weight gain, reducing inflammatory cytokines, and improving insulin resistance induced by a high-fat diet. Additionally, EEP enhanced glucose tolerance. Through collision-induced dissociation experiments, we identified 26 metabolites, with 4-hydroxyphenylacetic acid, protocatechuic acid, caffeic acid, ferulic acid, hippuric acid, histidine, and tryptophan emerging as potential biomarkers. Notably, tryptophan exhibited the highest content at 8.25 mg/g. Our research facilitates rapid profiling of colon metabolites, underscoring its significant potential for broader applications in animal metabolomic studies.

Insights into the interplay between gut microbiota and lipid metabolism in the obesity management of canines and felines

Obesity is a prevalent chronic disease that has significant negative impacts on humans and our companion animals, including dogs and cats. Obesity occurs with multiple comorbidities, such as diabetes, hypertension, heart disease and osteoarthritis in dogs and cats. A direct link between lipid metabolism dysregulation and obesity-associated diseases has been implicated. However, the understanding of such pathophysiology in companion animals is limited. This review aims to address the role of lipid metabolism in various metabolic disorders associated with obesity, emphasizing the involvement of the gut microbiota. Furthermore, we also discuss the management of obesity, including approaches like nutritional interventions, thus providing novel insights into obesity prevention and treatment for canines and felines.

Bisphenol S exposure induces intestinal inflammation via altering gut microbiome

Bisphenol S (BPS), a substitute for bisphenol A, is widely used in the manufacture of food packaging materials, raising concern over its toxicity. However, evidence is still lacking on whether gut microbiota involved in BPS induced intestinal inflammation in mammals, as well as its underlying mechanism. Using mouse BPS exposure model, we found intestinal inflammation characterized by shortened colon length, crypt distortion, macrophage accumulation and increased apoptosis. As for gut microbiota, 16s rRNA gene amplicon sequencing showed BPS exposure induced gut dysbiosis, including increased pro-inflammatory microbes such as Ileibacterium, and decreased anti-inflammatory genera such as Lactobacillus, Blautia and Romboutsia. Besides, LC-MS/MS-based untargeted metabolomic analysis indicated BPS impaired both bacteria and host metabolism. Additionally, transcriptome analysis of the intestine revealed abnormal gene expression in intestinal mucosal barrier and inflammation. More importantly, treating mice with antibiotics significantly attenuated BPS-induced gut inflammation via the regulation of both bacterial and host metabolites, indicating the role of gut microbiota. Collectively, BPS exposure induces intestinal inflammation via altering gut microbiota in mouse. This study provides the possibility of madecassic acid, an anti-inflammatory metabolite, to prevent BPS-induced intestinal inflammation and also new insights in understanding host-microbiota interaction in BPS toxicity.

Saccharina Japonica Polysaccharides Suppress High-Fat Diet-Induced Obesity and Modulate Gut Microbiota Composition and Function

Recent studies have highlighted the potential of Saccharina japonica Polysaccharides (SJPs) in alleviating high-fat diet (HFD)-induced obesity by regulating gut microbiota, which warrants further exploration to elucidate the underlying structure-activity relationship. In this study, five polysaccharide fractions (Sj-T, Sj-T-1, Sj-T-2, Sj-T-3, and Sj-T-4) with different structure characteristics were prepared from S. japonica, and their effects on HFD-induced obesity and gut microbiota composition were investigated using C57BL/6J mice. The results revealed that oral administration of Sj-T considerably suppressed HFD-induced obesity, glucose metabolic dysfunction, and other disordered symptoms. While, Sj-T-2, which has the lowest molecular weight, was the most effective in alleviating HFD-induced obesity and had the second-best effect on improving HFD-induced impaired glucose tolerance among the five SJPs. Supplementation with SJPs significantly modulated HFD-induced gut microbiota dysbiosis both at the phylum and species levels, such as enriching Desulfobacterota and Actinobacteriota, while suppressing the abundance of Bacteroidota. Sj-T also dramatically restored the gut microbiota composition by modulating the abundance of many crucial gut bacterial taxa, including s_Bacteroides_acidifaciens, s_Lachnospiraceae _bacterium, and g_Lachnospiraceae_NK4A136_group. Besides, SJPs also dramatically altered the function of gut microbiota, including many carbohydrate-metabolism enzymes. This study highlights the potential of SJPs in preventing obesity and restoring intestinal homeostasis in obese individuals.

Gut microbiota-derived metabolites tune host homeostasis fate

The gut microbiota, housing trillions of microorganisms within the gastrointestinal tract, has emerged as a critical regulator of host health and homeostasis. Through complex metabolic interactions, these microorganisms produce a diverse range of metabolites that substantially impact various physiological processes within the host. This review aims to delve into the intricate relationships of gut microbiota-derived metabolites and their influence on the host homeostasis. We will explore how these metabolites affect crucial aspects of host physiology, including metabolism, mucosal integrity, and communication among gut tissues. Moreover, we will spotlight the potential therapeutic applications of targeting these metabolites to restore and sustain host equilibrium. Understanding the intricate interplay between gut microbiota and their metabolites is crucial for developing innovative strategies to promote wellbeing and improve outcomes of chronic diseases.

Gut flora in multiple sclerosis: implications for pathogenesis and treatment

ABSTRACT

Multiple sclerosis is an inflammatory disorder characterized by inflammation, demyelination, and neurodegeneration in the central nervous system. Although current first-line therapies can help manage symptoms and slow down disease progression, there is no cure for multiple sclerosis. The gut-brain axis refers to complex communications between the gut flora and the immune, nervous, and endocrine systems, which bridges the functions of the gut and the brain. Disruptions in the gut flora, termed dysbiosis, can lead to systemic inflammation, leaky gut syndrome, and increased susceptibility to infections. The pathogenesis of multiple sclerosis involves a combination of genetic and environmental factors, and gut flora may play a pivotal role in regulating immune responses related to multiple sclerosis. To develop more effective therapies for multiple sclerosis, we should further uncover the disease processes involved in multiple sclerosis and gain a better understanding of the gut-brain axis. This review provides an overview of the role of the gut flora in multiple sclerosis.

Oxylipin profiling for clinical research: Current status and future perspectives

Oxylipins are potent lipid mediators with increasing interest in clinical research. They are usually measured in systemic circulation and can provide a wealth of information regarding key biological processes such as inflammation, vascular tone, or blood coagulation. Although procedures still require harmonization to generate comparable oxylipin datasets, performing comprehensive profiling of circulating oxylipins in large studies is feasible and no longer restricted by technical barriers. However, it is essential to improve and facilitate the biological interpretation of complex oxylipin profiles to truly leverage their potential in clinical research. This requires regular updating of our knowledge about the metabolism and the mode of action of oxylipins, and consideration of all factors that may influence circulating oxylipin profiles independently of the studied disease or condition. This review aims to provide the readers with updated and necessary information regarding oxylipin metabolism, their different forms in systemic circulation, the current limitations in deducing oxylipin cellular effects from in vitro bioactivity studies, the biological and technical confounding factors needed to consider for a proper interpretation of oxylipin profiles.

Host-diet-microbiota interplay in intestinal nutrition and health

The intestine is populated by a complex and dynamic assortment of microbes, collectively called gut microbiota, that interact with the host and contribute to its metabolism and physiology. Diet is considered a key regulator of intestinal microbiota, as ingested nutrients interact with and shape the resident microbiota composition. Furthermore, recent studies underscore the interplay of dietary and microbiota-derived nutrients, which directly impinge on intestinal stem cells regulating their turnover to ensure a healthy gut barrier. Although advanced sequencing methodologies have allowed the characterization of the human gut microbiome, mechanistic studies assessing diet-microbiota-host interactions depend on the use of genetically tractable models, such as Drosophila melanogaster. In this review, we first discuss the similarities between the human and fly intestines and then we focus on the effects of diet and microbiota on nutrient-sensing signaling cascades controlling intestinal stem cell self-renewal and differentiation, as well as disease. Finally, we underline the use of the Drosophila model in assessing the role of microbiota in gut-related pathologies and in understanding the mechanisms that mediate different whole-body manifestations of gut dysfunction.

Prebiotics, probiotics, synbiotics and postbiotics to adolescents in metabolic syndrome

The prevalence of childhood and adolescent obesity has globally reached alarming dimensions and many adolescents affected by obesity already present one or more obesity-related comorbidities. In recent years, emerging evidence supporting the role of gut microbiota in the pathophysiology of metabolic diseases has been reported and the use of prebiotics, probiotics, synbiotics and postbiotics as a strategy to manipulate gut microbiota has become popular. The aim of this review is to explore the relationship between gut microbiota and metabolic syndrome in adolescents and to discuss the potential use of prebiotics, probiotics, synbiotics and postbiotics for the prevention and treatment of this clinical picture in adolescence. According to the most recent literature, prebiotics, probiotics and synbiotics have no clear effect on MetS, but a possible modulation of anthropometric parameters has been observed after synbiotic supplementation. Only one study has examined the role of postbiotics in alleviating metabolic complications in children with obesity but not in adolescents. More extensive research is needed to support the conclusions drawn so far and to develop effective microbiome-based interventions that may help improving the quality of life of children and adolescents exposed to the increasing prevalence of MetS.

Gut microbiota is involved in male reproductive function: a review

Globally, ~8%-12% of couples confront infertility issues, male-related issues being accountable for 50%. This review focuses on the influence of gut microbiota and their metabolites on the male reproductive system from five perspectives: sperm quality, testicular structure, sex hormones, sexual behavior, and probiotic supplementation. To improve sperm quality, gut microbiota can secrete metabolites by themselves or regulate host metabolites. Endotoxemia is a key factor in testicular structure damage that causes orchitis and disrupts the blood-testis barrier (BTB). In addition, the gut microbiota can regulate sex hormone levels by participating in the synthesis of sex hormone-related enzymes directly and participating in the enterohepatic circulation of sex hormones, and affect the hypothalamic-pituitary-testis (HPT) axis. They can also activate areas of the brain that control sexual arousal and behavior through metabolites. Probiotic supplementation can improve male reproductive function. Therefore, the gut microbiota may affect male reproductive function and behavior; however, further research is needed to better understand the mechanisms underlying microbiota-mediated male infertility.

Fructooligosaccharides Intake during Pregnancy Improves Metabolic Phenotype of Offspring in High Fat Diet-Induced Obese Mice

SCOPE

Obesity and metabolic diseases are closely associated, and individuals who become obese are also prone to type 2 diabetes and cardiovascular disorders. Gut microbiota is mediated by diet and can influence host metabolism and the incidence of metabolic disorders. Recent studies have suggested that improving gut microbiota through a fructooligosaccharide (FOS)-supplemented diet may ameliorate obesity and other metabolic disorders. Although accumulating evidence supports the notion of the developmental origins of health and disease, the underlying mechanisms remain obscure.

METHODS AND RESULTS

ICR mice are fed AIN-93G formula-based cellulose -, FOS-, acetate-, or propionate-supplemented diets during pregnancy. Offspring are reared by conventional ICR foster mothers for 4 weeks; weaned mice are fed high fat diet for 12 weeks and housed individually. The FOS and propionate offspring contribute to suppressing obesity and improving glucose intolerance. Gut microbial compositions in FOS-fed mothers and their offspring are markedly changed. However, the beneficial effect of FOS diet on the offspring is abolished when antibiotics are administered to pregnant mice.

CONCLUSION

The findings highlight the link between the maternal gut environment and the developmental origin of metabolic syndrome in offspring. These results open novel research avenues into preemptive therapies for metabolic disorders by targeting the maternal gut microbiota.

The gut lactic acid bacteria metabolite, 10-oxo-cis-6,trans-11-octadecadienoic acid, suppresses inflammatory bowel disease in mice by modulating the NRF2 pathway and GPCR-signaling

Various gut bacteria, including Lactobacillus plantarum, possess several enzymes that produce hydroxy fatty acids (FAs), oxo FAs, conjugated FAs, and partially saturated FAs from polyunsaturated FAs as secondary metabolites. Among these derivatives, we identified 10-oxo-cis-6,trans-11-octadecadienoic acid (γKetoC), a γ-linolenic acid (GLA)-derived enon FA, as the most effective immunomodulator, which inhibited the antigen-induced immunoactivation and LPS-induced production of inflammatory cytokines. The treatment with γKetoC significantly suppressed proliferation of CD4+ T cells, LPS-induced activation of bone marrow-derived dendritic cells (BMDCs), and LPS-induced IL-6 release from peritoneal cells, splenocytes, and CD11c+ cells isolated from the spleen. γKetoC also inhibited the release of inflammatory cytokines from BMDCs stimulated with poly-I:C, R-848, or CpG. Further in vitro experiments using an agonist of GPR40/120 suggested the involvement of these GPCRs in the effects of γKetoC on DCs. We also found that γKetoC stimulated the NRF2 pathway in DCs, and the suppressive effects of γKetoC and agonist of GPR40/120 on the release of IL-6 and IL-12 were reduced in Nrf2-/- BMDCs. We evaluated the role of NRF2 in the anti-inflammatory effects of γKetoC in a dextran sodium sulfate-induced colitis model. The oral administration of γKetoC significantly reduced body weight loss, improved stool scores, and attenuated atrophy of the colon, in wild-type C57BL/6 and Nrf2+/- mice with colitis. In contrast, the pathology of colitis was deteriorated in Nrf2-/- mice even with the administration of γKetoC. Collectively, the present results demonstrated the involvement of the NRF2 pathway and GPCRs in γKetoC-mediated anti-inflammatory responses.

The gut microbiome-prostate cancer crosstalk is modulated by dietary polyunsaturated long-chain fatty acids

The gut microbiota modulates response to hormonal treatments in prostate cancer (PCa) patients, but whether it influences PCa progression remains unknown. Here, we show a reduction in fecal microbiota alpha-diversity correlating with increase tumour burden in two distinct groups of hormonotherapy naïve PCa patients and three murine PCa models. Fecal microbiota transplantation (FMT) from patients with high PCa volume is sufficient to stimulate the growth of mouse PCa revealing the existence of a gut microbiome-cancer crosstalk. Analysis of gut microbial-related pathways in mice with aggressive PCa identifies three enzymes responsible for the metabolism of long-chain fatty acids (LCFA). Supplementation with LCFA omega-3 MAG-EPA is sufficient to reduce PCa growth in mice and cancer up-grading in pre-prostatectomy PCa patients correlating with a reduction of gut Ruminococcaceae in both and fecal butyrate levels in PCa patients. This suggests that the beneficial effect of omega-3 rich diet is mediated in part by modulating the crosstalk between gut microbes and their metabolites in men with PCa.

The Probiotic Kluyveromyces lactis JSA 18 Alleviates Obesity and Hyperlipidemia in High-Fat Diet C57BL/6J Mice

Obesity poses a significant threat to various health conditions such as heart diseases, diabetes, high blood pressure, and heart attack, with the gut microbiota playing a crucial role in maintaining the body's energy balance. We identified a novel probiotic fungal strain, Kluyveromyces lactis JSA 18 (K. lactis), which was isolated from yak milk and was found to possess anti-obesity properties. Additionally, Lactobacillus plantarum CGMCC 8198 (LP8198) from our previous study was also included to evaluate its anti-obesity properties. The findings indicated that K. lactis caused a notable reduction in weight gain, liver and fat indexes, and hyperlipidemia in mice fed a high-fat diet (HFD). Administering K. lactis and LP8198 to mice on a high-fat diet resulted in a reduction of serum triglyceride levels. Furthermore, the supplements reduced ALT and AST activity, and inhibited the production of inflammatory cytokines such as TNF-α and IL-1β. In addition, lipid metabolism was enhanced by the downregulation of ACC1, PPAR-γ, SREBP-1, and Fasn. Moreover, this study found that K. lactis and LP8198 have little effect on gut bacteria. Additionally, K. lactis partially influenced intestinal fungi, while LP8198 had a minor influence on gut mycobiota. The main goal of this research was to show how effective K. lactis can be as a probiotic in combating obesity.

New insights into the interactions between the gut microbiota and the inflammatory response to ulcerative colitis in a mouse model of dextran sodium sulfate and possible mechanisms of action for treatment with PE&AFWE

BACKGROUND

Inflammatory bowel disease (IBD), comprising Crohn's disease (CD) and ulcerative colitis (UC), is a heterogeneous state of chronic intestinal inflammation. Intestinal innate immunity, including innate immune cells, defends against pathogens and excessive entry of gut microbiota, while preserving immune tolerance to resident intestinal microbiota, and may be characterized by its capacity to produce a rapid and nonspecific reaction. The association between microbiota dysbiosis and the pathogenesis of IBD is complex and dynamic. When the intestinal ecosystem is in dysbiosis, the reduced abundance and diversity of intestinal gut microbiota make the host more vulnerable to the attack of exogenous and endogenous pathogenic gut microbiota. The aim of our study was to comprehensively assess the relationship between microbial populations within UC, the signaling pathways of pathogenic gut microbe therein and the inflammatory response, as well as to understand the effects of using PE&AFWE (poppy extract [Papaver nudicaule L.] and Artemisia frigida Willd. extract) on UC modulation.

METHODS

A UC mouse model was established by inducing SPF-grade C57BL/6 mice using dextrose sodium sulfate (DSS). Based on metagenomic sequencing to characterize the gut microbiome, the relationship between gut microbiota dysbiosis and gut microbiota was further studied using random forest and Bayesian network analysis methods, as well as histopathological analysis.

RESULTS

(1) We found that the 5 gut microbiota with the highest relative abundance of inflammatory bowel disease UC model gut microbiota were consistent with the top 5 ranked natural bacteria. There were three types of abundance changes in the model groups: increases (Chlamydiae/Proteobacteria and Deferribacteres), decreases (Firmicutes), and no significant changes (Bacteroidetes). The UC model group was significantly different from the control group, with 1308 differentially expressed species with abundance changes greater than or equal to 2-fold. (2) The proportion of the fecal flora in the UC group decreased by 37.5% in the Firmicutes and increased by 14.29% in the proportion of Proteobacteria compared to the control group before treatment. (3) The significantly enriched and increased signaling pathways screened were the 'arachidonic acid metabolic pathway' and the 'phagosomal pathway', which both showed a decreasing trend after drug administration. (4) Based on the causal relationship between different OTUs and the UC model/PE&AFWE administration, screening for directly relevant OTU networks, the UC group was found to directly affect OTU69, followed by a cascade of effects on OTU12, OTU121, OTU93, and OTU7, which may be the pathway of action that initiated the pathological changes in normal mice. (5) We identified a causal relationship between common differentially expressed OTUs and PE&AFWE and UC in the pre- and post-PE&AFWE-treated groups. Thereby, we learned that PE&AFWE can directly affect OTU90, after which it inhibits UC, inhibiting the activity of arachidonic acid metabolic pathway by affecting OTU118, which in turn inhibits the colonization of gut microbiota by OTU93 and OTU7. (6) Histopathological observation and scoring (HS) of the colon showed that there was a significant difference between the model group and the control group (p < 0.001), and that there was a significant recovery in both the sulfasalazine (SASP)and the PE&AFWE groups after the administration of the drug (p < 0.0001).

CONCLUSION

We demonstrated causal effects and inflammatory metabolic pathways in gut microbiota dysbiosis and IBD, with five opportunistic pathogens directly contributing to IBD. PE&AFWE reduced the abundance of proteobacteria in the gut microbiota, and histopathology showed significant improvement.

Staphylococcus aureus oleate hydratase produces ligands that activate host PPARα

Commensal gut bacteria use oleate hydratase to release a spectrum of hydroxylated fatty acids using host-derived unsaturated fatty acids. These compounds are thought to attenuate the immune response, but the underlying signaling mechanism(s) remain to be established. The pathogen Staphylococcus aureus also expresses an oleate hydratase and 10-hydroxyoctadecanoic acid (h18:0) is the most abundant oleate hydratase metabolite found at Staphylococcal skin infection sites. Here, we show h18:0 stimulates the transcription of a set of lipid metabolism genes associated with the activation of peroxisome proliferator activated receptor (PPAR) in the RAW 264.7 macrophage cell line and mouse primary bone marrow-derived macrophages. Cell-based transcriptional reporter assays show h18:0 selectively activates PPARα. Radiolabeling experiments with bone marrow-derived macrophages show [1-14C]h18:0 is not incorporated into cellular lipids, but is degraded by β-oxidation, and mass spectrometry detected shortened fragments of h18:0 released into the media. The catabolism of h18:0 was >10-fold lower in bone marrow-derived macrophages isolated from Ppara -/- knockout mice, and we recover 74-fold fewer S. aureus cells from the skin infection site of Ppara -/- knockout mice compared to wildtype mice. These data identify PPARα as a target for oleate hydratase-derived hydroxy fatty acids and support the existence of an oleate hydratase-PPARα signaling axis that functions to suppress the innate immune response to S. aureus.

Metabolic effects of milk fatty acids: A literature review

Milk and dairy products are known to have a significant role in human development and tissue maintenance due to their high nutritional value. With the higher incidence of obesity and metabolic diseases, nutrition and public health authorities have recommended the intake of fat-free or low-fat dairy due to the saturated fatty acid content of whole-fat products and their effect on serum cholesterol levels. However, recent studies have questioned the association between milk fat consumption and cardiometabolic risk. This literature review aims to compile the scientific evidence of the metabolic effects of milk fatty acids in clinical and basic research studies, as well as their relationship with metabolic disorders and gut microbiota composition. Research shows that various milk fatty acids exert effects on metabolic alterations (obesity, type 2 diabetes and cardiovascular diseases) by modifying glucose homeostasis, inflammation and lipid profile-related factors. Additionally, recent studies have associated the consumption of milk fatty acids with the production of metabolites and the promotion of healthy gut microbiota. From mainly observational studies, evidence suggests that milk and dairy fatty acids are not directly linked to cardiometabolic risk, but further controlled research is necessary to clarify such findings and to assess whether dietary recommendations to choose low-fat dairy foods are necessary for the population for the prevention of obesity and cardiometabolic disease.

Microbiota-gut-brain axis and its therapeutic applications in neurodegenerative diseases

The human gastrointestinal tract is populated with a diverse microbial community. The vast genetic and metabolic potential of the gut microbiome underpins its ubiquity in nearly every aspect of human biology, including health maintenance, development, aging, and disease. The advent of new sequencing technologies and culture-independent methods has allowed researchers to move beyond correlative studies toward mechanistic explorations to shed light on microbiome-host interactions. Evidence has unveiled the bidirectional communication between the gut microbiome and the central nervous system, referred to as the "microbiota-gut-brain axis". The microbiota-gut-brain axis represents an important regulator of glial functions, making it an actionable target to ameliorate the development and progression of neurodegenerative diseases. In this review, we discuss the mechanisms of the microbiota-gut-brain axis in neurodegenerative diseases. As the gut microbiome provides essential cues to microglia, astrocytes, and oligodendrocytes, we examine the communications between gut microbiota and these glial cells during healthy states and neurodegenerative diseases. Subsequently, we discuss the mechanisms of the microbiota-gut-brain axis in neurodegenerative diseases using a metabolite-centric approach, while also examining the role of gut microbiota-related neurotransmitters and gut hormones. Next, we examine the potential of targeting the intestinal barrier, blood-brain barrier, meninges, and peripheral immune system to counteract glial dysfunction in neurodegeneration. Finally, we conclude by assessing the pre-clinical and clinical evidence of probiotics, prebiotics, and fecal microbiota transplantation in neurodegenerative diseases. A thorough comprehension of the microbiota-gut-brain axis will foster the development of effective therapeutic interventions for the management of neurodegenerative diseases.

A Cohort Study of the Influence of the 12-Component Modified Japanese Diet Index on Oral and Gut Microbiota in the Japanese General Population

The Japanese diet is a healthy dietary pattern, and the oral or gut microbiota have been identified as the main factors underlying the beneficial effects of the Japanese diet. However, epidemiological studies on Japanese dietary patterns calculated from daily eating habits in the general population yielded inconsistent findings. This study aimed to determine the association between the 12-component modified Japanese Diet Index (mJDI12) and the oral and gut microbiota in the general population of a rural area in Japan. After propensity-score matching, 396 participants (198 each in the low and high mJDI12 groups) were picked out. One year after the follow up survey, we reclassified the subjects and compared the low and high mJDI12 groups again. Participants with a high mJDI12 had a higher relative abundance of butyric acid-producing bacteria in their gut microbiota. Moreover, the significantly higher dietary fiber intake in the high mJDI12 group suggested that the high intake of dietary fiber contributed to an increase in butyric acid-producing bacteria in the gut. In contrast, in individuals with a high mJDI12, only Allpprevotella was decreased in the oral microbiota. Thus, the Japanese dietary pattern can have beneficial effects by improving the oral and gut microbiota.

Production, Composition and Nutritional Properties of Organic Milk: A Critical Review

Milk is one of the most valuable products in the food industry with most milk production throughout the world being carried out using conventional management, which includes intensive and traditional systems. The intensive use of fertilizers, antibiotics, pesticides and concerns regarding animal health and the environment have given increasing importance to organic dairy and dairy products in the last two decades. This review aims to compare the production, nutritional, and compositional properties of milk produced by conventional and organic dairy management systems. We also shed light on the health benefits of milk and the worldwide scenario of the organic dairy production system. Most reports suggest milk has beneficial health effects with very few, if any, adverse effects reported. Organic milk is reported to confer additional benefits due to its lower omega-6-omega-3 ratio, which is due to the difference in feeding practices, with organic cows predominantly pasture fed. Despite the testified animal, host, and environmental benefits, organic milk production is difficult in several regions due to the cost-intensive process and geographical conditions. Finally, we offer perspectives for a better future and highlight knowledge gaps in the organic dairy management system.

Dynamics of the Gut Microbiota and Faecal and Serum Metabolomes during Pregnancy-A Longitudinal Study

Normal pregnancy involves numerous physiological changes, including changes in hormone levels, immune responses, and metabolism. Although several studies have shown that the gut microbiota may have an important role in the progression of pregnancy, these findings have been inconsistent, and the relationship between the gut microbiota and metabolites that change dynamically during and after pregnancy remains to be clarified. In this longitudinal study, we comprehensively profiled the temporal dynamics of the gut microbiota, Bifidobacterium communities, and serum and faecal metabolomes of 31 women during their pregnancies and postpartum periods. The microbial composition changed as gestation progressed, with the pregnancy and postpartum periods exhibiting distinct bacterial community characteristics, including significant alterations in the genera of the Lachnospiraceae or Ruminococcaceae families, especially the Lachnospiraceae FCS020 group and Ruminococcaceae UCG-003. Metabolic dynamics, characterised by changes in nutrients important for fetal growth (e.g., docosatrienoic acid), anti-inflammatory metabolites (e.g., trans-3-indoleacrylic acid), and steroid hormones (e.g., progesterone), were observed in both serum and faecal samples during pregnancy. Moreover, a complex correlation was identified between the pregnancy-related microbiota and metabolites, with Ruminococcus1 and Ruminococcaceae UCG-013 making important contributions to changes in faecal and serum metabolites, respectively. Overall, a highly coordinated microbiota-metabolite regulatory network may underlie the pregnancy process. These findings provide a foundation for enhancing our understanding of the molecular processes occurring during the progression of pregnancy, thereby contributing to nutrition and health management during this period.

Chronic exposure to parabens promotes non-alcoholic fatty liver disease in association with the changes of the gut microbiota and lipid metabolism

Non-alcoholic fatty liver disease (NAFLD) has become a serious public health issue due to changing dietary patterns and composition. However, the relationship between NAFLD occurrence and food additives, such as preservatives, remains unknown. This study aimed to evaluate the toxicity of parabens, namely methylparaben (MeP) and ethylparaben (EtP), in relation to NAFLD occurrence in mice under different dietary conditions. Exposure to MeP and EtP exacerbated high-fat diet (HFD)-induced obesity, glucose intolerance, higher serum lipid concentrations, and fat accumulation by upregulating genes involved in lipid metabolism. Untargeted metabolomics revealed that arachidonic acid (AA) metabolism was the top enriched pathway upon MeP and EtP exposure in the presence of HFD. 11,12-Epoxyeicosatrienoic acid (11,12-EET) was the most abundant AA metabolite and was significantly reduced upon exposure to MeP or EtP. Moreover, an integrative analysis of differential fecal taxa at the genus level and serum AA metabolites revealed significant associations. In addition, MeP and EtP enhanced lipid accumulation in AML12 cells and HepG2 cells cultured with oleic acid. 11,12-EET supplementation could significantly alleviate lipid accumulation by suppressing the expression of lipid metabolism-related genes and proteins. The present study suggests that chronic exposure to MeP and EtP promoted NAFLD via gut microbiota-dependent AA metabolism. These results highlight the need for reducing oral exposure to synthetic preservatives to improve metabolic disturbance under HFD conditions.

New mechanistic insights of anti-obesity by sleeve gastrectomy-altered gut microbiota and lipid metabolism

Background

The obesity epidemic has been on the rise due to changes in living standards and lifestyles. To combat this issue, sleeve gastrectomy (SG) has emerged as a prominent bariatric surgery technique, offering substantial weight reduction. Nevertheless, the mechanisms that underlie SG-related bodyweight loss are not fully understood.

Methods

In this study, we conducted a collection of preoperative and 3-month postoperative serum and fecal samples from patients who underwent laparoscopic SG at the First Affiliated Hospital of Shandong First Medical University (Jinan, China). Here, we took an unbiased approach of multi-omics to investigate the role of SG-altered gut microbiota in anti-obesity of these patients. Non-target metabolome sequencing was performed using the fecal and serum samples.

Results

Our data show that SG markedly increased microbiota diversity and Rikenellaceae, Alistipes, Parabacteroides, Bactreoidales, and Enterobacteraies robustly increased. These compositional changes were positively correlated with lipid metabolites, including sphingolipids, glycerophospholipids, and unsaturated fatty acids. Increases of Rikenellaceae, Alistipes, and Parabacteroide were reversely correlated with body mass index (BMI).

Conclusion

In conclusion, our findings provide evidence that SG induces significant alterations in the abundances of Rikenellaceae, Alistipes, Parabacteroides, and Bacteroidales, as well as changes in lipid metabolism-related metabolites. Importantly, these changes were found to be closely linked to the alleviation of obesity. On the basis of these findings, we have identified a number of microbiotas that could be potential targets for treatment of obesity.

Gut commensal Christensenella minuta modulates host metabolism via acylated secondary bile acids

A strong correlation between gut microbes and host health has been observed in numerous gut metagenomic cohort studies. However, the underlying mechanisms governing host-microbe interactions in the gut remain largely unknown. Here we report that the gut commensal Christensenella minuta modulates host metabolism by generating a previously undescribed class of secondary bile acids with 3-O-acylation substitution that inhibit the intestinal farnesoid X receptor. Administration of C. minuta alleviated features of metabolic disease in high fat diet-induced obese mice associated with a significant increase in these acylated bile acids, which we refer to as 3-O-acyl-cholic acids. Specific knockout of intestinal farnesoid X receptor in mice counteracted the beneficial effects observed in their wild-type counterparts. Finally, we showed that 3-O-acyl-CAs were prevalent in healthy humans but significantly depleted in patients with type 2 diabetes. Our findings indicate a role for C. minuta and acylated bile acids in metabolic diseases.

CD36: The Bridge between Lipids and Tumors

It has been found that the development of some cancers can be attributed to obesity, which is associated with the excessive intake of lipids. Cancer cells undergo metabolic reprogramming, shifting from utilizing glucose to fatty acids (FAs) for energy. CD36, a lipid transporter, is highly expressed in certain kinds of cancer cells. High expressions of CD36 in tumor cells triggers FA uptake and lipid accumulation, promoting rapid tumor growth and initiating metastasis. Meanwhile, immune cells in the tumor microenvironment overexpress CD36 and undergo metabolic reprogramming. CD36-mediated FA uptake leads to lipid accumulation and has immunosuppressive effects. This paper reviews the types of FAs associated with cancer, high expressions of CD36 that promote cancer development and progression, effects of CD36 on different immune cells in the tumor microenvironment, and the current status of CD36 as a therapeutic target for the treatment of tumors with high CD36 expression.

Gut microbial metabolites reveal diet-dependent metabolic changes induced by nicotine administration

The gut microbiota has emerged as an important factor that potentially influences various physiological functions and pathophysiological processes such as obesity and type 2 diabetes mellitus. Accumulating evidence from human and animal studies suggests that gut microbial metabolites play a critical role as integral molecules in host-microbe interactions. Notably, several dietary environment-dependent fatty acid metabolites have been recognized as potent modulators of host metabolic homeostasis. More recently, nicotine, the primary active molecule in tobacco, has been shown to potentially affect host metabolism through alterations in the gut microbiota and its metabolites. However, the mechanisms underlying the interplay between host nutritional status, diet-derived microbial metabolites, and metabolic homeostasis during nicotine exposure remain unclear. Our findings revealed that nicotine administration had potential effects on weight regulation and metabolic phenotype, independent of reduced caloric intake. Moreover, nicotine-induced body weight suppression is associated with specific changes in gut microbial composition, including Lactobacillus spp., and KetoB, a nicotine-sensitive gut microbiota metabolite, which could be linked to changes in host body weight, suggesting its potential role in modulating host metabolism. Our findings highlight the remarkable impact of the interplay between nutritional control and the gut environment on host metabolism during smoking and smoking cessation.

Gut microbiota-palmitoleic acid-interleukin-5 axis orchestrates benzene-induced hematopoietic toxicity

Due to the annual increase in its production and consumption in occupational environments, the adverse blood outcomes caused by benzene are of concern. However, the mechanism of benzene-induced hematopoietic damage remains elusive. Here, we report that benzene exposure causes hematopoietic damage in a dose-dependent manner and is associated with disturbances in gut microbiota-long chain fatty acids (LCFAs)-inflammation axis. C57BL/6J mice exposed to benzene for 45 days were found to have a significant reduction in whole blood cells and the suppression of hematopoiesis, an increase in Bacteroides acidifaciens and a decrease in Lactobacillus murinus. Recipient mice transplanted with fecal microbiota from benzene-exposed mice showed potential for hematopoietic disruption, LCFAs, and interleukin-5 (IL-5) elevation. Abnormally elevated plasma LCFAs, especially palmitoleic acid (POA) exacerbated benzene-induced immune-inflammation and hematopoietic damage via carnitine palmitoyltransferase 2 (CPT2)-mediated disorder of fatty acid oxidation. Notably, oral administration of probiotics protects the mice against benzene-induced hematopoietic toxicity. In summary, our data reveal that the gut microbiota-POA-IL-5 axis is engaged in benzene-induced hematopoietic damage. Probiotics might be a promising candidate to prevent hematopoietic abnormalities from benzene exposure.

Precocious infant fecal microbiome promotes enterocyte barrier dysfuction, altered neuroendocrine signaling and associates with increased childhood obesity risk

Early life gut microbiome composition has been correlated with childhood obesity, though microbial functional contributions to disease origins remain unclear. Here, using an infant birth cohort (n = 349) we identify a distinct fecal microbiota composition in 1-month-old infants with the lowest rate of exclusive breastfeeding, that relates with higher relative risk for obesity and overweight phenotypes at two years. Higher-risk infant fecal microbiomes exhibited accelerated taxonomic and functional maturation and broad-ranging metabolic reprogramming, including reduced concentrations of neuro-endocrine signals. In vitro, exposure of enterocytes to fecal extracts from higher-risk infants led to upregulation of genes associated with obesity and with expansion of nutrient sensing enteroendocrine progenitor cells. Fecal extracts from higher-risk infants also promoted enterocyte barrier dysfunction. These data implicate dysregulation of infant microbiome functional development, and more specifically promotion of enteroendocrine signaling and epithelial barrier impairment in the early-life developmental origins of childhood obesity.

Gut microbiota-derived fatty acid and sterol metabolites: biotransformation and immunomodulatory functions

Commensal microorganisms in the human gut produce numerous metabolites by using small molecules derived from the host or diet as precursors. Host or dietary lipid molecules are involved in energy metabolism and maintaining the structural integrity of cell membranes. Notably, gut microbes can convert these lipids into bioactive signaling molecules through their biotransformation and synthesis pathways. These microbiota-derived lipid metabolites can affect host physiology by influencing the body's immune and metabolic processes. This review aims to summarize recent advances in the microbial transformation and host immunomodulatory functions of these lipid metabolites, with a special focus on fatty acids and steroids produced by our gut microbiota.

Construction and efficacy evaluation of chitosan-based nanoparticles for colon-targeted release of linoleic acid in rat pups

Long chain fatty acids in the colon play important roles in infant development. This study aimed to establish a colon-targeted long chain fatty acid release system in rat pups, with linoleic acid (LA) as the target model. LA-loaded chitosan nanoparticles (LA-CS NPs) synthesized via ionic crosslinkage showed spherical surface morphology and favorable encapsulation efficiency (84.96 %). In vivo distribution studies of LA-CS NPs demonstrated a significant increase in LA concentration in the colonic content after a 12-hour administration period. Additionally, oral administration of the delivery system (CS NPs: 18 μg/g/d, LA-CS NPs: 24 μg/g/d) exhibited no detrimental effects on the health of rat pups. In conclusion, this study presents a promising strategy for the targeted delivery of fatty acid to the colon in rat pups.

High dietary intake of unsaturated fatty acids is associated with improved insulin resistance - a cross-sectional study based on the NHANES database

BACKGROUND

A moderate intake of unsaturated fatty acids (UFA) is associated positively with improved insulin resistance. The aim of this study was to investigate the relationship between the dietary intake of unsaturated fatty acids/total fats (UFA/TF) and insulin resistance.

METHODS

15,560 participants were selected from the National Health and Nutrition Examination Survey (NHANES) database enrolled between March 2017 and 2020, and excluded those under 20 years of age, pregnant, or with missing data for key research items. Finally, 7,630 participants were included in the study. R software was used for data analysis that included: (1) general descriptive statistics; (2) comparison of differences in baseline information of three UFA/TF groups, namely low, medium, and high ratios; (3) calculation of the correlation between the UFA/TF ratio and markers of insulin resistance: triglyceride-glucose index (TyG) and homeostatic model assessment for insulin resistance (HOMA-IR); (4) stratification of the study subjects into two groups, with or without insulin resistance, using a cut-off value of HOMA-IR ≥ 2, followed by logistic regression analysis to examine the relationship between UFA/TF and insulin resistance status in the two groups; and (5) further stratification of the subjects according to age, gender, body mass index (BMI), race, total energy intake, total protein, total carbohydrate, total sugars, total dietary fiber, total fat, alcohol consumption, diabetes, hypercholesterolemia to analyze the impact of UFA/TF on insulin resistance status in different subgroups.

RESULTS

(1) A high UFA/TF level was associated with a low TyG index and HOMA-IR [β (vs. TyG index) = -0.559, 95% CI: (-0.821~-0.297), P < 0.001; β (vs. HOMA-IR) = -0.742, 95% CI: (-1.083~-0.402), P < 0.001]. This negative relationship became more pronounced when UFA/TF exceeded 57.9% (i.e., the higher group). (2) Logistic regression analysis showed that a higher UFA/TF level was associated with a lower risk of developing insulin resistance [Q3 vs. Q1: 0.838 (95%CI: 0.709 ~ 0.991); P for trend = 0.038]. After adjusting for covariates such as gender, age, and BMI, this protective effect remained significant (P value < 0.05). (3) Analysis also showed that increased UFA/TF intake reduced the risk of developing insulin resistance (OR = 0.266, 95% CI: (0.075 ~ 0.946), P = 0.041). Subgroup analysis showed that although elevated UFA/TF intake showed no statistically significant difference in its effect in most subgroups, the large study population in this study provides valuable insights on potential changes. Increased UFA/TF intake may confer relatively greater benefits within specific subgroups, particularly among the elderly [Q3 age group, OR = 0.114, 95%CI: (0.012 ~ 1.078), P = 0.058], females [OR = 0.234, 95%CI: (0.041 ~ 1.333), P = 0.102], those with a BMI ≤ 25 kg/m²[OR = 0.191, 95%CI: (0.016 ~ 2.344), P = 0.196], and individuals without hypercholesterolemia [OR = 0.207, 95%CI: (0.042 ~ 1.013), P = 0.0519]. The impact of high UFA/TF levels within subgroups based on the presence or absence of coronary heart disease and stroke displayed contrasting trends. In those without coronary heart disease, there was a significant protective effect against insulin resistance [OR = 0.254, 95% CI: (0.07 ~ 0.929), P = 0.0384], while in the stroke subgroup, a significantly protective effect against insulin resistance was observed [OR = 0.002, 95%CI: (0 ~ 0.695), P = 0.0376].

CONCLUSION

A high dietary intake of UFA relative to total fat consumption could be a protective factor against the risk of developing insulin resistance.

The Promise of Precision Nutrition for Modulation of the Gut Microbiota as a Novel Therapeutic Approach to Acute Graft-versus-host Disease

Acute graft-versus-host disease (aGVHD) is a severe side effect of allogeneic hematopoietic stem cell transplantation (aHSCT) that has complex phenotypes and often unpredictable outcomes. The current management is not always able to prevent aGVHD. A neglected actor in the management of aGVHD is the gut microbiota. Gut microbiota dysbiosis after aHSCT is caused by many factors and may contribute to the development of aGVHD. Diet and nutritional status modify the gut microbiota and a wide range of products are now available to manipulate the gut microbiota (pro-, pre-, and postbiotics). New investigations are testing the effect of probiotics and nutritional supplements in both animal models and human studies, with encouraging results. In this review, we summarize the most recent literature about the probiotics and nutritional factors able to modulate the gut microbiota and we discuss the future perspective in developing new integrative therapeutic approaches to reducing the risk of graft-versus-host disease in patients undergoing aHSCT.

Early-Life Sugar Consumption Affects the Microbiome in Juvenile Mice

SCOPE

The composition of the gut microbiota is influenced by the dietary nutrient. Sugar has been linked with many metabolic health disorders such as heart disease, metabolic syndrome, and immune disorders. Long-term consumption of sugar influences the landscape of gut microbiota by altering the gut microbial population called dysbiosis. This study aims to evaluate the impact of long-term consumption of high sugar diet (HSD) on the diversity of gut microbiota.

METHODS AND RESULTS

CD1 mice are given high concentration of sugar for 15 weeks followed by a recovery period of 10 weeks. Real-time polymerase chain reaction and 16S rRNA next-generation sequencing methods employ to identify microbiome diversity. The results show that Firmicutes and Bacteroidetes are the predominant phyla in control, cecum, and fecal samples. Firmicutes population are gradually increased in treated samples even after the recovery period, whereas Bacteroidetes abundance slightly reduces throughout the study.

CONCLUSION

The present study shows that the impact of long period of high sugar diet consumption alters the diversity of normal gut flora which can be restored after 10 weeks of sugar withdrawal. This indicates that the intervention of healthy and nutritious diet influences gut microbes and this can be beneficial in reducing the implication of early life metabolic disorders such as obesity.

The influence of microbiota on ferroptosis in intestinal diseases

Ferroptosis is a distinctive form of iron-dependent necrotic cell death, characterized by excessive lipid peroxidation on cellular membranes and compromised cellular antioxidant defenses. Multiple metabolic pathways, including iron and lipid metabolism, as well as antioxidant systems, contribute to the execution of ferroptosis. The gut microbiota exerts regulatory effects on ferroptosis through its microbial composition, biological functions, and metabolites. Notably, most pathogenic bacteria tend to promote ferroptosis, thereby inducing or exacerbating diseases, while most probiotics have been shown to protect against cell death. Given microbiota colonization in the gut, an intimate association is found between intestinal diseases and microbiota. This review consolidates the essential aspects of ferroptotic processes, emphasizing key molecules and delineating the intricate interplay between gut microbiota and ferroptosis. Moreover, this review underscores the potential utility of gut microbiota modulation in regulating ferroptosis for the treatment of intestinal diseases.

Gut microbiota in obesity and related complications: Unveiling the complex interplay

In recent years, the obesity epidemic has escalated into a serious public health catastrophe that is only getting worse. However, research into the pathophysiological pathways behind the obesity development and the illnesses that it is associated with is ongoing. In the last decades, it is now clear that the gut microbiota plays a significant role in the genesis and progression of obesity and obesity-related illnesses, particularly changes in its metabolites and composition as obesity progresses. Here, we provide a summary of the processes by which variations in gut metabolite levels and the composition of gut microbiota affect obesity and associated disorders. The bacteria residing in the gut release several chemicals that influence the appetite control, metabolism, and other systems. Since it can either encourage or restrict the deposition of fat in several different ways, the gut microbiota's role in obesity is debatable. Additionally, we go over potential therapeutic approaches that could be utilized to alter gut microbiota composition and focus on the important metabolic pathways associated with obesity and metabolic disorders linked to obesity.

Combating Obesity: Harnessing the Synergy of Postbiotics and Prebiotics for Enhanced Lipid Excretion and Microbiota Regulation

Obesity is a chronic metabolic disease that can be induced by a high-fat diet (HFD) and predisposes to a variety of complications. In recent years, various bioactive substances, such as probiotics, prebiotics, and postbiotics, have been widely discussed because of their good anti-lipid and anti-inflammatory activities. In this paper, soybean protein isolate was used as a substrate to prepare the postbiotic. Compound prebiotics (galactose oligosaccharides, fructose oligosaccharides, and lactitol) preparation Aunulife Postbiotics and Prebiotics Composition (AYS) is the research object. Weight loss and bowel movements in mice induced by a high-fat diet were studied. Moreover, qualitative and quantitative analyses of small-molecule metabolites in AYS were performed to identify the functional molecules in AYS. After 12 weeks of feeding, the weight gain of mice that were fed with high-dose AYS (group H) and low-dose AYS (group L) from 4 to 12 weeks was 6.72 g and 5.25 g (p < 0.05), both of which were significantly lower than that of the high-fat diet (group DM, control group) group (7.73 g) (p < 0.05). Serum biochemical analysis showed that TC, TG, and LDL-C levels were significantly lower in mice from the H and L groups (p < 0.05). In addition, the fecal lipid content of mice in the L group reached 5.89%, which was significantly higher than that of the DM group at 4.02% (p < 0.05). The study showed that AYS changed the structure of the intestinal microbiota in mice on a high-fat diet, resulting in a decrease in the relative abundance of Firmicutes and Muribaculaceae and an increase in the relative abundance of Bacteroidetes, Verrucomicrobia, and Lactobacillus. The metabolomics study results of AYS showed that carboxylic acids and derivatives, and organonitrogen compounds accounted for 51.51% of the AYS metabolites, among which pantothenate, stachyose, betaine, and citrate had the effect of preventing obesity in mice. In conclusion, the administration of prebiotics and postbiotic-rich AYS reduces weight gain and increases fecal lipid defecation in obese mice, potentially by regulating the intestinal microbiota of mice on a high-fat diet.

AhR and CYP1B1 Control Oxygen Effects on Bone Marrow Progenitor Cells: The Enrichment of Multiple Olfactory Receptors as Potential Microbiome Sensors

Polycyclic aromatic hydrocarbon (PAH) pollutants and microbiome products converge on the aryl hydrocarbon receptor (AhR) to redirect selective rapid adherence of isolated bone marrow (BM) cells. In young adult mice, Cyp1b1-deficiency and AhR activation by PAH, particularly when prolonged by Cyp1a1 deletion, produce matching gene stimulations in these BM cells. Vascular expression of Cyp1b1 lowers reactive oxygen species (ROS), suppressing NF-κB/RelA signaling. PAH and allelic selectivity support a non-canonical AhR participation, possibly through RelA. Genes stimulated by Cyp1b1 deficiency were further resolved according to the effects of Cyp1b1 and Cyp1a1 dual deletions (DKO). The adherent BM cells show a cluster of novel stimulations, including select developmental markers; multiple re-purposed olfactory receptors (OLFR); and α-Defensin, a microbial disruptor. Each one connects to an enhanced specific expression of the catalytic RNA Pol2 A subunit, among 12 different subunits. Mesenchymal progenitor BMS2 cells retain these features. Cyp1b1-deficiency removes lymphocytes from adherent assemblies as BM-derived mesenchymal stromal cells (BM-MSC) expand. Cyp1b1 effects were cell-type specific. In vivo, BM-MSC Cyp1b1 expression mediated PAH suppression of lymphocyte progenitors. In vitro, OP9-MSC sustained these progenitors, while Csf1 induced monocyte progenitor expansion to macrophages. Targeted Cyp1b1 deletion (Cdh5-Cre; Cyp1b1fl/fl) established endothelium control of ROS that directs AhR-mediated suppression of B cell progenitors. Monocyte Cyp1b1 deletion (Lyz2-Cre; Cyp1b1fl/fl) selectively attenuated M1 polarization of expanded macrophages, but did not enhance effects on basal M2 polarization. Thus, specific sources of Cyp1b1 link to AhR and to an OLFR network to provide BM inflammatory modulation via diverse microbiome products.

Newly isolated Lactobacillus paracasei strain modulates lung immunity and improves the capacity to cope with influenza virus infection

BACKGROUND

The modulation of immune responses by probiotics is crucial for local and systemic immunity. Recent studies have suggested a correlation between gut microbiota and lung immunity, known as the gut-lung axis. However, the evidence and mechanisms underlying this axis remain elusive.

RESULTS

In this study, we screened various Lactobacillus (L.) strains for their ability to augment type I interferon (IFN-I) signaling using an IFN-α/β reporter cell line. We identified L. paracasei (MI29) from the feces of healthy volunteers, which showed enhanced IFN-I signaling in vitro. Oral administration of the MI29 strain to wild-type B6 mice for 2 weeks resulted in increased expression of IFN-stimulated genes and pro-inflammatory cytokines in the lungs. We found that MI29-treated mice had significantly increased numbers of CD11c+PDCA-1+ plasmacytoid dendritic cells and Ly6Chi monocytes in the lungs compared with control groups. Pre-treatment with MI29 for 2 weeks resulted in less weight loss and lower viral loads in the lung after a sub-lethal dose of influenza virus infection. Interestingly, IFNAR1-/- mice did not show enhanced viral resistance in response to oral MI29 administration. Furthermore, metabolic profiles of MI29-treated mice revealed changes in fatty acid metabolism, with MI29-derived fatty acids contributing to host defense in a Gpr40/120-dependent manner.

CONCLUSIONS

These findings suggest that the newly isolated MI29 strain can activate host defense immunity and prevent infections caused by the influenza virus through the gut-lung axis. Video Abstract.

Lactic acid bacteria in relieving constipation: mechanism, clinical application, challenge, and opportunity

Constipation is a prevalent gastrointestinal symptom that can considerably affect a patients' quality of life. Although several drugs have been used to treat constipation, they are associated with high costs, side effects, and low universality. Therefore, alternative intervention strategies are urgently needed. Traditional lactic acid bacteria (LAB), such as Bifidobacterium and Lactobacillus, play a vital role in regulating intestinal microecology and have demonstrated favorable effects in constipation; however, a comprehensive review of their constipation relief mechanisms is limited. This review summarizes the pathogenesis of constipation and the relationship between intestinal motility and gut microbiota, elucidates the possible mechanism by which LAB alleviates of constipation through a systematic summary of animal and clinical research, and highlights the challenges and applications of LAB in the treatment of constipation. Our review can improve our understanding of constipation, and advance targeted microecological therapeutic agents, such as LAB.

A gut microbial metabolite of linoleic acid ameliorates liver fibrosis by inhibiting TGF-β signaling in hepatic stellate cells

The antidiabetic drug pioglitazone ameliorates insulin resistance by activating the transcription factor PPARγ. In addition to its blood glucose-lowering action, pioglitazone exerts pleiotropic effects including amelioration of nonalcoholic fatty liver disease (NAFLD)/nonalcoholic steatohepatitis (NASH). The mechanism by which pioglitazone achieves this latter effect has remained unclear, however. We here show that pioglitazone administration increases the amount of linoleic acid (LA) metabolites in adipose tissue of KK-Ay mice. These metabolites are produced by lactic acid bacteria in the gut, and pioglitazone also increased the fraction of Lactobacillus in the gut microbiota. Administration of the LA metabolite HYA (10-hydroxy-cis-12-octadecenoic acid) to C57BL/6 J mice fed a high-fat diet improved liver histology including steatosis, inflammatory cell infiltration, and fibrosis. Gene ontology analysis of RNA-sequencing data for the liver revealed that the top category for genes downregulated by HYA treatment was related to extracellular matrix, and the expression of individual genes related to fibrosis was confirmed to be attenuated by HYA treatment. Mechanistically, HYA suppressed TGF-β-induced Smad3 phosphorylation and fibrosis-related gene expression in human hepatic stellate cells (LX-2). Our results implicate LA metabolites in the mechanism by which pioglitazone ameliorates liver fibrosis, and they suggest that HYA is a potential therapeutic for NAFLD/NASH.

Gut microbiota bridges dietary nutrients and host immunity

Dietary nutrients and the gut microbiota are increasingly recognized to cross-regulate and entrain each other, and thus affect host health and immune-mediated diseases. Here, we systematically review the current understanding linking dietary nutrients to gut microbiota-host immune interactions, emphasizing how this axis might influence host immunity in health and diseases. Of relevance, we highlight that the implications of gut microbiota-targeted dietary intervention could be harnessed in orchestrating a spectrum of immune-associated diseases.

Akkermansia muciniphila supplementation improves glucose tolerance in intestinal Ffar4 knockout mice during the daily light to dark transition

IMPORTANCE

Alterations in the intestinal environment are associated with various diseases, and FFAR4 is abundantly enriched in the intestine, where it has been shown to have the ability to regulate intestinal hormone secretion and intestinal microbiota; here, we confirmed previous reports. Meanwhile, we found that intestinal FFAR4 regulates glucagon-like peptide 1 secretion by decreasing Akkermansia muciniphila abundance and show that such change is associated with the level of glucose utilization at ZT12 in mice. Intestinal FFAR4 deficiency leads to severely impaired glucose tolerance at the ZT12 moment in mice, and Akkermansia muciniphila supplementation ameliorates the abnormal glucose utilization at the ZT12 moment caused by FFAR4 deficiency, which is very similar to the dawn phenomenon in diabetic patients. Collectively, our data suggest that intestinal Ffar4 deteriorates glucose tolerance at the daily light to dark transition by affecting Akkermansia muciniphila.

Targeting gut-liver axis by dietary lignans ameliorate obesity: evidences and mechanisms

An imbalance between energy consumption and energy expenditure causes obesity. It is characterized by increased adipose accumulation and accompanied by chronic low-grade inflammation. Many studies have suggested that the gut microbiota of the host mediates the relationship between high-fat diet consumption and the development of obesity. Diet and nutrition of the body are heavily influenced by gut microbiota. The alterations in the microbiota in the gut may have effects on the homeostasis of the host's energy levels, systemic inflammation, lipid metabolism, and insulin sensitivity. The liver is an important organ for fat metabolism and gut-liver axis play important role in the fat metabolism. Gut-liver axis is a bidirectional relationship between the gut and its microbiota and the liver. As essential plant components, lignans have been shown to have different biological functions. Accumulating evidences have suggested that lignans may have lipid-lowering properties. Lignans can regulate the level of the gut microbiota and their metabolites in the host, thereby affecting signaling pathways related to fat synthesis and metabolism. These signaling pathways can make a difference in inhibiting fat accumulation, accelerating energy metabolism, affecting appetite, and inhibiting chronic inflammation. It will provide the groundwork for future studies on the lipid-lowering impact of lignans and the creation of functional meals based on those findings.

Exploring the potential mechanism of Rubus corchorifolius L. fruit polyphenol-rich extract in mitigating non-alcoholic fatty liver disease by integration of metabolomics and transcriptomics profiling

Nonalcoholic fatty liver disease (NAFLD), as the commonest chronic liver disease, is accompanied by liver oxidative stress and inflammatory responses. Herein, the extract obtained from Rubus corchorifolius fruits was purified and characterized for its polyphenol composition. The liver protective effect of the purified R. corchorifolius fruit extract (RCE) on mice with high-fat-diet (HFD)-induced NAFLD were investigated, and the potential mechanisms were explored through the integration of transcriptomics and metabolomics. Results showed that the polyphenolic compounds in RCE mainly included (-)-epigallocatechin, procyanidin B2, keracyanin, vanillin, dihydromyricetin, and ellagic acid. In addition, RCE intervention ameliorated liver and mitochondrial damage, which was evidenced by decreased indices of oxidative stress, liver function markers, and lipid profile levels. The liver metabonomics research revealed that RCE intervention affected the metabolic pathways of metabolites, including linoleic acid metabolism, galactose metabolism, alanine, aspartate and glutamate metabolism, retinol metabolism, glycine, serine and threonine metabolism, tryptophan metabolism, aminoacyl-tRNA biosynthesis, riboflavin metabolism, starch and sucrose metabolism, and arachidonic acid metabolism. Additionally, liver transcriptomics research indicated that pathways like fatty acid degradation, circadian rhythm, valine, leucine and isoleucine degradation, primary bile acid biosynthesis, cytokine-cytokine receptor interaction, adipocytokine signaling pathway, glutathione metabolism, lipid and atherosclerosis were significantly enriched. The transcriptomics and metabolomics analysis demonstrated that RCE intervention had significant modulatory effects on the metabolic pathways associated with glycolipid metabolism. Moreover, RT-PCR results verified that RCE intervention regulated liver mRNA levels associated with the inflammatory response. Therefore, our findings suggest that the intake of RCE might be an effective strategy to alleviate liver damage.

Potential associations between organic dairy products, gut microbiome, and gut health: A review

Organic products have received longstanding, widespread attention for their nutritional and ecological benefits, as they are said to have certain positive health attributes and contain fewer harmful compounds than conventional (or non-organic) products. We reviewed the recent literature to examine potential associations between nutrient composition, gut microbiota, and gut health effects in recent comparative studies of organic and conventional dairy products. Trends of increased ratios of omega-3 to omega-6 polyunsaturated fatty acids and unsaturated to saturated fat, increased fat-soluble vitamin content, and decreased levels of certain pernicious contaminants in organic milk were observed across the studies reviewed. Studies of the metabolism of these nutrients in both in vitro and in vivo settings, and their or their metabolites' interaction with the intestinal epithelium show that nutrients enriched in organic dairy products may support host nutrient uptake and mediate gut inflammation. Research on the effects of single food products or classes of food products on gut health is rare. The extent of these benefits is highly likely to be mediated by both the magnitude of the difference in nutrient types and quantities, and by dietary intake levels of dairy products. Intervention studies directly examining the different effects of organic and conventional dairy products on gut health in humans are needed to further elucidate this relationship.

GABA and fermented litchi juice enriched with GABA promote the beneficial effects in ameliorating obesity by regulating the gut microbiota in HFD-induced mice

Gamma-aminobutyric acid (GABA) dietary intervention is considered to have therapeutic potential against obesity. Microbial enrichment is an effective strategy to naturally and safely enhance GABA production in food. As litchi is "the king of GABA" in fruits, the retention or enrichment of its content during processing has been a key issue in the litchi industry. This study aimed to investigate the potential of GABA and fermented litchi juice enriched with GABA (FLJ) to protect against obesity in a high-fat diet (HFD) mouse model. Supplementation of GABA and FLJ displayed an anti-obesogenic effect by attenuating body weight gain, fat accumulation, and oxidative damage, and improving the serum lipid profile and hepatic function. Sequencing (16S rRNA) of fecal samples indicated that GABA and FLJ intervention displayed different regulatory effects on HFD-induced gut microbiota dysbiosis at different taxonomic levels. The microbial diversity, the relative abundance of Firmicutes and Bacteroidetes as well as the F/B ratio of GABA and FLJ groups were reversed compared to those of the HFD-induced mice. Our finding broadens the potential mechanisms by which GABA regulates gut flora in the amelioration of obesity and provides guidance for developing FLJ as a functional food to prevent obesity.