Eicosapentaenoic and docosahexaenoic acids attenuate hyperglycemia through the microbiome-gut-organs axis in db/db mice

Effect of docosahexaenoic acid as an anti-inflammatory for Caco-2 cells and modulating agent for gut microbiota in children with obesity (the DAMOCLE study)

PURPOSE

Docosahexaenoic acid (DHA) is a long-chain omega-3 polyunsaturated fatty acid. We investigated the dual health ability of DHA to modulate gut microbiota in children with obesity and to exert anti-inflammatory activity on human intestinal Caco-2 cells.

METHODS

In a pilot study involving 18 obese children (8-14 years), participants received a daily DHA supplement (500 mg/day) and dietary intervention from baseline (T0) to 4 months (T1), followed by dietary intervention alone from 4 months (T1) to 8 months (T2). Fecal samples, anthropometry, biochemicals and dietary assessment were collected at each timepoint. At preclinical level, we evaluated DHA's antioxidant and anti-inflammatory effects on Caco-2 cells stimulated with Hydrogen peroxide (H2O2) and Lipopolysaccharides (LPS), by measuring also Inducible nitric oxide synthase (iNOS) levels and cytokines, respectively.

RESULTS

Ten children were included in final analysis. No major changes were observed for anthropometric and biochemical parameters, and participants showed a low dietary compliance at T1 and T2. DHA supplementation restored the Firmicutes/Bacteroidetes ratio that was conserved also after the DHA discontinuation at T2. DHA supplementation drove a depletion in Ruminococcaceae and Dialisteraceae, and enrichment in Bacteroidaceae, Oscillospiraceae, and Akkermansiaceae. At genus level, Allisonella was the most decreased by DHA supplementation. In Caco-2 cells, DHA decreased H2O2-induced reactive oxygen species (ROS) and nitric oxide (NO) production via iNOS pathway modulation. Additionally, DHA modulated proinflammatory (IL-1β, IL-6, IFN-γ, TNF-α) and anti-inflammatory (IL-10) cytokine production in LPS-stimulated Caco-2 cells.

CONCLUSION

An improvement in gut dysbiosis of children with obesity seems to be triggered by DHA and to continue after discontinuation. The ability to modulate gut microbiota, matches also with an anti-inflammatory effect of DHA on Caco-2 cells.

Nutraceuticals in the management of autonomic function and related disorders: A comprehensive review

Nutraceuticals have been described as phytocomplexes when derived from foods of plant origin or a pool of secondary metabolites when derived from foods of animal origin, which are concentrated and administered in an appropriate form and can promote beneficial health effects in the prevention/treatment of diseases. Considering that pharmaceutical medications can cause side effects, there is a growing interest in using nutraceuticals as an adjuvant therapeutic tool for several disorders involving autonomic dysfunction, such as obesity, atherosclerosis and other cardiometabolic diseases. This review summarizes and discusses the evidence from the literature on the effects of various nutraceuticals on autonomic control, addressing the gut microbiota modulation, production of secondary metabolites from bioactive compounds, and improvement of physical and chemical properties of cell membranes. Additionally, the safety of nutraceuticals and prospects are discussed. Probiotics, resveratrol, quercetin, curcumin, nitrate, inositol, L-carnosine, and n-3 polyunsaturated fatty acids (n-3 PUFAs) are among the nutraceuticals most studied to improve autonomic dysfunction in experimental animal models and clinical trials. Further human studies are needed to elucidate the effects of nutraceuticals formulated of multitarget compounds and their underlying mechanisms of action, which could benefit conditions involving autonomic dysfunction.

Dietary nitrate maintains intestinal epithelia homeostasis in aged mice

The intestinal tract, which is the primary site of digestion and absorption of nutrients, is one of the most vulnerable organs during aging. Dietary nitrate, which is mainly derived from the diet and absorbed in the intestinal tract, is a key messenger that connecting oral and general health. However, whether dietary nitrate regulates intestinal tract homeostasis remains unclear. Our data revealed that the serum and salivary nitrate levels decreased during mice aging. The functional proteins of the epithelial barrier (E-cadherin, Claudin-1 and Zonula Occludens-1) in the colon tissues decreased during the aging process. Long-term nitrate supplement in drinking water restored the serum and salivary nitrate levels and increased the functional proteins expression of the colon epithelial barrier. Dietary nitrates increase the relative abundance of some intestinal probiotics, particularly those associated with the production of short-chain fatty acids, such as Blautia, Alloprevotella, Butyricicoccus, and Ruminococcaceae, while promoting the butyric acid production in the colon. Moreover, the expression of Sialin (encoded by Slc17a5), which is a nitrate transporter, increased in the colon epithelial cells by nitrate supplementation. The epithelial cell-conditional Slc17a5-knockout mutant mice (K14-cre; Slc17a5fl/fl) revealed that the functional proteins expression of the colon epithelial barrier and the proliferation of PCNA-positive intestinal epithelial cells in the colon crypts was significantly decreased compared with those of the K14-cre; Slc17a5fl/+ mice. Taken together, our findings suggested that nitrate supplementations were associated with the increased expression of colonic epithelial barriers-related proteins and the increased Sialin expression. Nitrate may serve as a potential therapeutic approach in maintaining aged colonic homeostasis.

Impact of omega-3 fatty acids on hypertriglyceridemia, lipidomics, and gut microbiome in patients with type 2 diabetes

BACKGROUND

Fish oil (FO), a mixture of omega-3 fatty acids mainly comprising docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), has been recommended for patients with type 2 diabetes (T2D) and hypertriglyceridemia. However, its effects on lipidomic profiles and gut microbiota and the factors influencing triglyceride (TG) reduction remain unclear.

METHODS

We conducted a 12-week, randomized, double-blind, placebo-controlled trial in 309 Chinese patients with T2D with hypertriglyceridemia (ClinicalTrials.gov: NCT03120299). Participants were randomly assigned (1:1) to receive either 4 g FO or corn oil for 12 weeks. The primary outcome was changes in serum TGs and the lipidomic profile, and the secondary outcome included changes in the gut microbiome and other metabolic variables.

FINDINGS

The FO group had significantly better TG reduction (mean [95% confidence interval (CI)]: -1.51 [-2.01, -1.01] mmol/L) compared to the corn oil group (-0.66 [-1.15, -0.16] mmol/L, p = 0.02). FO significantly altered the serum lipid profile by reducing low-unsaturated TG species and increasing those containing DHA or EPA. FO had minor effects on gut microbiota, while baseline microbial features predicted the TG response to FO better than phenotypic or lipidomic features, potentially mediated by specific lipid metabolites. A total of 9 lipid metabolites significantly mediated the link between 4 baseline microbial variables and the TG response to FO supplementation.

CONCLUSIONS

Our findings demonstrate differential impacts of omega-3 fatty acids on lipidomic and microbial profiles in T2D and highlight the importance of baseline gut microbiota characteristics in predicting the TG-lowering efficacy of FO.

FUNDING

This study was funded by the National Nature Science Foundation.

Highland Barley β-Glucan Relieves Symptoms of Colitis via PPARα-Mediated Intestinal Stem Cell Proliferation

Intestinal stem cells (ISCs) are necessary to maintain intestinal renewal. Here, we found that the highland barley β-glucan (HBG) alleviated pathological symptoms and promoted the proliferation of intestinal stem cells in colitis mice. Notably, metabolomics studies showed that docosahexaenoic acid (DHA) was significantly increased by the HBG treatment. DHA is a ligand for peroxisome proliferator-activated receptor α (PPARα), which can promote ISC proliferation. Expectedly, HBG facilitated the expression of intestinal PPARα and the proliferation of ISCs in colitis mice. Further experiments verified that DHA significantly facilitated the expression of PPARα and the proliferation of ISCs in intestinal organoids. Intriguingly, the effect of DHA on ISC proliferation was reversed by the PPARα inhibitor. Together, our data indicate that HBG might accelerate PPARα-mediated ISC proliferation through DHA. This provides new insights into the effective application of polysaccharides in maintaining intestinal homeostasis.

Maternal docosahexaenoic acid supplementation during lactation improves exercise performance, enhances intestinal glucose absorption and modulates gut microbiota in weaning offspring mice

Introduction

Intestinal dysfunction induced by weaning stress is common during breastfeeding period. Docosahexaenoic acid (DHA) is well known for promoting visual and brain development, but its effects on early intestinal development remain unknown. This study investigated the impact of maternal DHA supplementation during lactation on intestinal glucose absorption and gut microbiota in weaning offspring mice.

Materials and methods

Dams were supplemented with vehicle (control), 150 mg/(kg body weight · day) DHA (L-DHA), or 450 mg/(kg body weight · day) DHA (H-DHA) throughout lactation by oral administration. After weaning, pups were randomly divided into three groups for athletic analysis, microbial and proteomic analysis, biochemical analysis, 4-deoxy-4-fluoro-D-glucose (4-FDG) absorption test, and gene expression quantitation of glucose transport-associated proteins and mTOR signaling components.

Results

The H-DHA group exhibited enhanced grip strength and prolonged swimming duration compared to the control group. Additionally, there were significant increases in jejunal and ileal villus height, and expanded surface area of jejunal villi in the H-DHA group. Microbial analyses revealed that maternal DHA intake increased the abundance of beneficial gut bacteria and promoted metabolic pathways linked to carbohydrate and energy metabolism. Proteomic studies indicated an increased abundance of nutrient transport proteins and enrichment of pathways involved in absorption and digestion in the H-DHA group. This group also showed higher concentrations of glucose in the jejunum and ileum, as well as elevated glycogen levels in the liver and muscles, in contrast to lower glucose levels in the intestinal contents and feces compared to the control group. The 4-FDG absorption test showed more efficient absorption after oral 4-FDG gavage in the H-DHA group. Moreover, the expressions of glucose transport-associated proteins, GLUT2 and SGLT1, and the activation of mTOR pathway were enhanced in the H-DHA group compared to the control group. The L-DHA group also showed similar but less pronounced improvements in these aspects relative to the H-DHA group.

Conclusion

Our findings suggested that maternal DHA supplementation during lactation improves the exercise performance, enhances the intestinal glucose absorption by increasing the expressions of glucose transporters, and beneficially alters the structure of gut microbiome in weaning offspring mice.

Probiotic Lactobacillus rhamnosus GG improves insulin sensitivity and offspring survival via modulation of gut microbiota and serum metabolite in a sow model

BACKGROUND

Sows commonly experience insulin resistance in late gestation and lactation, causing lower feed intake and milk production, which can lead to higher mortality rates in newborn piglets. The probiotic Lactobacillus rhamnosus GG (LGG) is known to improve insulin resistance. However, whether supplementing LGG can improve insulin sensitivity in sows and enhance lactation performance, particularly the early survival of offspring remains unclear. Hence, we explored the effects and mechanisms of supplementing LGG during late gestation and lactation on sow insulin sensitivity, lactation performance, and offspring survival. In total, 20 sows were randomly allocated to an LGG (n = 10) and control group (n = 10).

RESULTS

In sows, LGG supplementation significantly improved insulin sensitivity during late gestation and lactation, increased feed intake, milk production and colostrum lactose levels in early lactation, and enhanced newborn piglet survival. Moreover, LGG treatment significantly reshaped the gut microbiota in sows, notably increasing microbiota diversity and enriching the relative abundance of insulin sensitivity-associated probiotics such as Lactobacillus, Bifidobacterium, and Bacteroides. Serum metabolite and amino acid profiling in late-gestation sows also revealed decreased branched-chain amino acid and kynurenine serum levels following LGG supplementation. Further analyses highlighted a correlation between mitigated insulin resistance in late pregnancy and lactation by LGG and gut microbiota reshaping and changes in serum amino acid metabolism. Furthermore, maternal LGG enhanced immunity in newborn piglets, reduced inflammation, and facilitated the establishment of a gut microbiota.

CONCLUSIONS

We provide the first evidence that LGG mitigates insulin resistance in sows and enhances offspring survival by modulating the gut microbiota and amino acid metabolism.

Effects of Adding Sphingomonas Z392 to Drinking Water on Growth Performance, Intestinal Histological Structure, and Microbial Community of Broiler Chickens

Probiotics are a prominent alternative to antibiotics in antimicrobial-free broiler farming. To assess the effect of Sphingomonas sp. Z392 (isolated and identified) on broiler growth, 600 one-day-old Kebao broiler chickens were randomly divided into a control group and an experimental group. Each group had three replicates, with 100 broiler chickens being raised in each replicate. Regarding the experimental group of broiler chickens, 4.0 × 105 CFU/mL of Sphingomonas Z392 was added to their drinking water. Then, the changes in broiler body weight, the EPI, intestinal histological structure, and gut microbiota were examined. The results show that the supplementation of the broilers' drinking water with 4 × 105 CFU/mL of Sphingomonas Z392 resulted in an increase in the relative abundance of Lactobacillus, Bacteroides, Lachnospiraceae, Aminobacterium, Oribacterium, Christensenellaceae, Faecalibacterium, Barnesiella, Ruminococcus, Parabacteroides, Phascolarctobacterium, Butyricicoccaceae, and Caproiciproducens, which have been reported to be positively correlated with the improved digestion and absorption of broiler chickens. The relative abundance of Odoribacter, Alistipes, Parabacteroides, and Rikenellaceae increased, and these have been reported to be negatively correlated with the occurrence of intestinal diseases. The relative abundance of Campylobacter, Shigella Castellani, Bilophila, Campylobacter, Clostridia, and Anaerotruncus decreased, and these have been reported to be positively correlated with the occurrence of intestinal diseases. At the same time, the following also increased: the integrity of small intestinal villus morphology; the number of goblet cells in small intestinal epithelial cells; the health of the mitochondria in the cytoplasm of jejunal villous epithelial cells; the number of lysosomes in the cytoplasm of goblet cells in the small intestinal epithelium, ileal villous epithelial cells, and mitochondria in the cytoplasm of large intestinal villous epithelial cells; the VH/CD of the ileum; and digestive, absorption, and defense capabilities. In particular, the final weight increased by 4.33%, and the EPI increased by 10.10%. Therefore, the supplementation of broiler drinking water with Sphingomonas generated better economic benefits from the broiler chickens.

Idiosyncratic Drug-Induced Liver Injury and Amoxicillin-Clavulanate: Spotlight on Gut Microbiota, Fecal Metabolome and Bile Acid Profile in Patients

Several hepatic disorders are influenced by gut microbiota, but its role in idiosyncratic drug-induced liver injury (iDILI), whose main causative agent is amoxicillin-clavulanate, remains unknown. This pioneering study aims to unravel particular patterns of gut microbiota composition and associated metabolites in iDILI and iDILI patients by amoxicillin-clavulanate (iDILI-AC). Thus, serum and fecal samples from 46 patients were divided into three study groups: healthy controls (n = 10), non-iDILI acute hepatitis (n = 12) and iDILI patients (n = 24). To evaluate the amoxicillin-clavulanate effect, iDILI patients were separated into two subgroups: iDILI non-caused by amoxicillin-clavulanate (iDILI-nonAC) (n = 18) and iDILI-AC patients (n = 6). Gut microbiota composition and fecal metabolome plus serum and fecal bile acid (BA) analyses were performed, along with correlation analyses. iDILI patients presented a particular microbiome profile associated with reduced fecal secondary BAs and fecal metabolites linked to lower inflammation, such as dodecanedioic acid and pyridoxamine. Moreover, certain taxa like Barnesiella, Clostridia UCG-014 and Eubacterium spp. correlated with significant metabolites and BAs. Additionally, comparisons between iDILI-nonAC and iDILI-AC groups unraveled unique features associated with iDILI when caused by amoxicillin-clavulanate. In conclusion, specific gut microbiota profiles in iDILI and iDILI-AC patients were associated with particular metabolic and BA status, which could affect disease onset and progression.

The use of an in vitro fecal fermentation model to uncover the beneficial role of omega-3 and punicic acid in gut microbiota alterations induced by a Western diet

The influence of gut microbiota in the onset and development of several metabolic diseases has gained attention over the last few years. Diet plays an essential role in gut microbiota modulation. Western diet (WD), characterized by high-sugar and high-fat consumption, alters gut microbiome composition, diversity index, microbial relative levels, and functional pathways. Despite the promising health effects demonstrated by polyunsaturated fatty acids, their impact on gut microbiota is still overlooked. The effect of Fish oil (omega-3 source) and Pomegranate oil (punicic acid source), and a mixture of both oils in gut microbiota modulation were determined by subjecting the oil samples to in vitro fecal fermentations. Cecal samples from rats from two different dietary groups: a control diet (CD) and a high-fat high-sugar diet (WD), were used as fecal inoculum. 16S amplicon metagenomics sequencing showed that Fish oil + Pomegranate oil from the WD group increased α-diversity. This sample can also increase the relative abundance of the Firmicutes and Bacteroidetes phylum as well as Akkermansia and Blautia, which were affected by the WD consumption. All samples were able to increase butyrate and acetate concentration in the WD group. Moreover, tyrosine concentrations, a precursor for dopamine and norepinephrine, increase in the Fish oil + Pomegranate oil WD sample. GABA, an important neurotransmitter, was also increased in WD samples. These results suggest a potential positive impact of these oils' mixture on gut-brain axis modulation. It was demonstrated, for the first time, the great potential of using a mixture of both Fish and Pomegranate oil to restore the gut microbiota changes associated with WD consumption.

The Dysregulation of Essential Fatty Acid (EFA) Metabolism May Be a Factor in the Pathogenesis of Sepsis

I propose that a deficiency of essential fatty acids (EFAs) and an alteration in their (EFAs) metabolism could be a major factor in the pathogenesis of sepsis and sepsis-related mortality. The failure of corticosteroids, anti-TNF-α, and anti-interleukin-6 monoclonal antibodies can be attributed to this altered EFA metabolism in sepsis. Vitamin C; folic acid; and vitamin B1, B6, and B12 serve as co-factors necessary for the activity of desaturase enzymes that are the rate-limiting steps in the metabolism of EFAs. The altered metabolism of EFAs results in an imbalance in the production and activities of pro- and anti-inflammatory eicosanoids and cytokines resulting in both hyperimmune and hypoimmune responses seen in sepsis. This implies that restoring the metabolism of EFAs to normal may form a newer therapeutic approach both in the prevention and management of sepsis and other critical illnesses.

Interactions between host and gut microbiota in gestational diabetes mellitus and their impacts on offspring

Gestational diabetes mellitus (GDM) is characterized by insulin resistance and low-grade inflammation, and most studies have demonstrated gut dysbiosis in GDM pregnancies. Overall, they were manifested as a reduction in microbiome diversity and richness, depleted short chain fatty acid (SCFA)-producing genera and a dominant of Gram-negative pathogens releasing lipopolysaccharide (LPS). The SCFAs functioned as energy substance or signaling molecules to interact with host locally and beyond the gut. LPS contributed to pathophysiology of diseases through activating Toll-like receptor 4 (TLR4) and involved in inflammatory responses. The gut microbiome dysbiosis was not only closely related with GDM, it was also vital to fetal health through vertical transmission. In this review, we summarized gut microbiota signature in GDM pregnancies of each trimester, and presented a brief introduction of microbiome derived SCFAs. We then discussed mechanisms of microbiome-host interactions in the physiopathology of GDM and associated metabolic disorders. Finally, we compared offspring microbiota composition from GDM with that from normal pregnancies, and described the possible mechanism.

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.

Effects of herbal dregs supplementation of Salvia miltiorrhiza and Isatidis Radix residues improved production performance and gut microbiota abundance in late-phase laying hens

The present study was designed to evaluate the effect of a mixture of Chinese medicinal residues (CMRs) consisting of Salvia miltiorrhiza residues (SMR) and Isatidis Radix residues (IRR) on productive performance, egg quality, serum lipid and hormone levels, liver and blood antioxidant capacity, oviduct inflammation levels, and gut microbiota in the late-laying stage. A total of 288 fifty-four-week-old BaShang long-tailed hens were divided into four groups. The feed trial period was 8 weeks. The control group was fed the basic diet as a CCMR group, supplemented with 3, 4, and 6% for the experimental groups LCMR, MCMR, and HCMR. The egg production rate of the MCMR group was 8.1% higher than that of the CCMR group (p < 0.05). Serum triglyceride (TG) levels of hens of the CMR-supplemented group were significantly decreased than those of the CCMR group (p < 0.05). The group supplemented with different levels of CMR had significantly higher serum HDL-C levels compared with the control group (p < 0.05). Follicle-stimulating hormone (FSH) and luteinizing hormone (LH) levels were remarkably increased for the LCMR and MCMR groups and significantly decreased for the HCMR group compared to CCMR (p < 0.05). Serum and liver glutathione peroxidase (GSH-PX) activities were significantly increased, and malondialdehyde (MDA) levels were significantly decreased in the MCMR group compared to the CCMR group (p < 0.05). The expression levels of tubal inflammatory factor markers (IL-4, IL-1β, TNF-α) in the MCMR and HCMR groups were consistent with the pathological findings of the sections. As for cecal microbiota, supplementation with CMR affected the alpha diversity of the cecum microbiome at the genus level. The Shannon index was significantly higher in the MCMR group than in the CCMR and HCMR groups (p < 0.05). Supplementation with different levels of CMR mainly regulated the ratio of intestinal Firmicutes to Bacteroidetes and the abundance of phyla such as Proteobacteria. In addition, CMR supplementation at different levels in the diet enriched lipid-metabolizing bacteria, such as Bacteroides and Ruminococcus_gnavus_group. Furthermore, according to linear discriminant analysis (LDA) effect size (LEfSe) analysis, the MCMR group showed an increase in the number of short-chain fatty acid-producing bacteria Romboutsia and fiber-degrading specialized bacteria Monoglobus. Therefore, supplementation of appropriate amounts of CMR to the diet of laying hens enhanced reproductive hormone levels, hepatic antioxidant capacity, and lipid metabolism, alleviated the levels of oviductal inflammatory factors, and modulated the abundance structure of bacterial flora to improve the late-laying performance and egg quality. The results of the current study showed that CMR is a beneficial feed supplement for chickens when added in moderation.

Theabrownin from Fu Brick tea ameliorates high-fat induced insulin resistance, hepatic steatosis, and inflammation in mice by altering the composition and metabolites of gut microbiota

Fu Brick tea belongs to fermented dark tea, which is one of the six categories of tea. Fu Brick tea has been reported to reduce adiposity and has beneficial effects in the treatment of hypercholesterolemia and cardiovascular disease. Theabrownin (TB) is one of the pigments with the most abundant content in Fu Brick tea. TB has also been reported to have lipid-lowering effects, but its mechanism remains unclear. We found that TB could effectively reduce the insulin resistance and fat deposition induced by a high fat diet (HFD), decrease inflammation in the liver, improve intestinal integrity, and reduce endotoxins in circulation. Further studies showed that TB increased the abundance of Verrucomicrobiota and reduced the abundance of Firmicutes and Desulfobacterota in the intestinal tract of obese mice. The alteration of gut microbiota is closely linked to the metabolic phenotype after TB treatment through correlation analysis. Moreover, TB changed the gut microbial metabolites including L-ornithine, α-ketoglutarate, and glutamine, which have also been found to be upregulated in the liver after TB intervention. In vitro, L-ornithine, α-ketoglutarate, or glutamine significantly reduced lipopolysaccharide (LPS)-induced inflammation in macrophages. Therefore, our results suggest that TB can reduce adiposity, systemic insulin resistance, and liver inflammation induced by a HFD through altering gut microbiota and improving the intestinal tight junction integrity. The metabolites of gut microbiota might also play a role in ameliorating the HFD-induced phenotype by TB.

The relationship between gastric microbiome features and responses to neoadjuvant chemotherapy in gastric cancer

Background

Emerging evidence demonstrates that the gastrointestinal microbiome has the potential to be a biomarker in neoadjuvant chemoradiotherapy for colorectal cancer (CRC). Yet studies on the impact of the gastric microbiome (GM) on the response to neoadjuvant chemotherapy (NACT) are still scarce.

Methods

Forty-eight patients with gastric cancer participated in this retrospective study, and 16S rRNA sequencing was performed to evaluate formalin-fixed and paraffin-embedded (FFPE) tissue biospecimens and fresh-frozen tissues.

Results

In this study, 16 bacterial taxa at different levels, including Bacillus, Anaerococcus, and Chloroflexi, were identified to be enriched before NACT in response (R) patients in group FFPE. In contrast, 6 bacterial taxa, such as Haemophilus, Veillonellaceae (Veillonella), etc. were enriched after NACT, in which we reported for the first time that the phylum Chloroflexi was enriched before NACT in R patients. Thirty-one bacterial taxa of Coriobacteriaceae, Ruminococcaceae, Veillonellaceae, and Lachnospiraceae were identified in group mucosa as being enriched in R patients. In comparison, 4 bacterial taxa dominated by the phylum Proteobacteria were enriched in NR patients. Notably, the family Veillonellaceae was found in both tissue samples, and the metabolic pathways, including the citrate cycle (TCA cycle) and various amino acids, including alanine, were found to be potentially predictive in both sample species.

Conclusion

There are differences in the features of the GM for different NACT response results. The causal relationship deserves to be confirmed by further investigations.

Effects of pork sausage on intestinal microecology and metabolism in mice

BACKGROUND

Processed meat, as an important part of the human diet, has been recognized as a carcinogen by the International Agency for Research on Cancer (IARC). Although numerous epidemiological reports supported the IARC's view, the relevant evidence of a direct association between processed meat and carcinogenicity has been insufficient and the mechanism has been unclear. This study aims to investigate the effects of pork sausage (as a representative example of processed meat) intake on gut microbial communities and metabolites of mice. Microbial communities and metabolites from all groups were analyzed using 16S rRNA gene sequencing and Ultra performance liquid chromatography-quadrupole-time of flight-mass spectrometer (UPLC-Q-TOF/MS), respectively.

RESULTS

The levels of Bacteroidetes, Bacteroides, Alloprevotella, Lactobacillus, Prevotella_9, Lachnospiraceae_NK4A136_group, Alistipes, Blautia, Proteobacteria, Firmicutes, Allobaculum, Helicobacter, Desulfovibrio, Clostridium_sensu_stricto_1, Ruminococcaceae_UCG-014, Lachnospiraceae_UCG-006 and Streptococcus (P < 0.05) were obviously altered in the mice fed a pork sausage diet. Twenty-seven metabolites from intestinal content samples and fourteen matabolites from whole blood samples were identified as potential biomarkers from multivariate analysis, including Phosphatidic acid (PA), Sphingomyelin (SM), Lysophosphatidylcholine (LysoPC), Diglyceride (DG), D-maltose, N-acylamides and so forth. The significant changes in these biomarkers demonstrate metabonomic variations in pork sausage treated rats, especially carbohydrate metabolism, lipid metabolism, and amino acid metabolism.

CONCLUSION

The present study provided evidence that a processed meat diet can increase the risk of colorectal cancer and other diseases significantly by altering the microbial community structure and disrupting the body's metabolic pathways. © 2023 Society of Chemical Industry.

Palmitoleic Acid Ameliorates Metabolic Disorders and Inflammation by Modulating Gut Microbiota and Serum Metabolites

SCOPE

Palmitoleic acid (POA) is an omega-7 monounsaturated fatty acid that has been suggested to improve metabolic disorders. However, it remains unclear whether gut microbiota plays a role in the amelioration of metabolic disorders by POA. This study aims to investigate the regulation of POA on metabolism, as well as systemic inflammation in HFD-fed mice from the perspective of serum metabolome and gut microbiome.

METHODS AND RESULTS

Thirty-six C57BL/6 male mice are randomly assigned to either a normal chow diet containing 1.9% w/w lard or an HFD containing 20.68% w/w lard or 20.68% w/w sea buckthorn pulp oil for 16 weeks. The study finds that POA significantly attenuated hyperlipidemia, insulin resistance, and inflammation in HFD-fed mice. POA supplementation significantly alters the composition of serum metabolites, particularly lipid metabolites in the glycerophospholipid metabolism pathway. POA obviously increases the abundance of Bifidobacterium and decreases the abundance of Allobaculum. Importantly, the study finds that glycerophosphocholine mediates the effect of Bifidobacterium on LDL-C, sphingomyelin mediates the effect of Bifidobacterium on IL-6, and maslinic acid mediates the effect of Allobaculum on IL-6.

CONCLUSION

The results suggest that exogenous POA can improve metabolic disorders and inflammation in HFD-fed mice, potentially by modulating the serum metabolome and gut microbiome.

Impacts of glutamate, an exercise-responsive metabolite on insulin signaling

AIMS

Disruption of the insulin signaling pathway leads to insulin resistance (IR). IR is characterized by impaired glucose and lipid metabolism. Elevated levels of circulating glutamate are correlated with metabolic indicators and may potentially predict the onset of metabolic diseases. Glutamate receptor antagonists have significantly enhanced insulin sensitivity, and improved glucose and lipid metabolism. Exercise is a well-known strategy to combat IR. The aims of our narrative review are to summarize preclinical and clinical findings to show the correlations between circulating glutamate levels, IR and metabolic diseases, discuss the causal role of excessive glutamate in IR and metabolic disturbance, and present an overview of the exercise-induced alteration in circulating glutamate levels.

MATERIALS AND METHODS

A literature search was conducted to identify studies on glutamate, insulin signaling, and exercise in the PubMed database. The search covered articles published from December 1955 to January 2024, using the search terms of "glutamate", "glutamic acid", "insulin signaling", "insulin resistance", "insulin sensitivity", "exercise", and "physical activity".

KEY FINDINGS

Elevated levels of circulating glutamate are correlated with IR. Excessive glutamate can potentially hinder the insulin signaling pathway through various mechanisms, including the activation of ectopic lipid accumulation, inflammation, and endoplasmic reticulum stress. Glutamate can also modify mitochondrial function through Ca2+ and induce purine degradation mediated by AMP deaminase 2. Exercise has the potential to decrease circulating levels of glutamate, which can be attributed to accelerated glutamate catabolism and enhanced glutamate uptake.

SIGNIFICANCE

Glutamate may act as a mediator in the exercise-induced improvement of insulin sensitivity.

Dual-Stimuli-Responsive Gut Microbiota-Targeting Nitidine Chloride-CS/PT-NPs Improved Metabolic Status in NAFLD

Background and Purpose

Nitidine chloride (NC) is a botanical drug renowned for its potent anti-inflammatory, antimalarial, and hepatocellular carcinoma-inhibiting properties; however, its limited solubility poses challenges to its development and application. To address this issue, we have devised a colon-targeted delivery system (NC-CS/PT-NPs) aimed at modulating the dysbiosis of the gut microbiota by augmenting the interaction between NC and the intestinal microbiota, thereby exerting an effect against nonalcoholic fatty liver disease.

Methods

The NC-CS/PT-NPs were synthesized using the ion gel method. Subsequently, the particle size distribution, morphology, drug loading efficiency, and release behavior of the NC-CS/PT-NPs were characterized. Furthermore, the impact of NC-CS/PT-NPs on non-alcoholic fatty liver disease (NAFLD) induced by a high-fat diet (HFD) in mice was investigated through serum biochemical analysis, ELISA, and histochemical staining. Additionally, the influence of NC-CS/PT-NPs on intestinal microbiota was analyzed using 16S rDNA gene sequencing.

Results

The nanoparticles prepared in this study have an average particle size of (255.9±5.10) nm, with an encapsulation rate of (72.83±2.13) % and a drug loading of (4.65±0.44) %. In vitro release experiments demonstrated that the cumulative release rate in the stomach and small intestine was lower than 22.0%, while it reached 66.75% in the colon. In vivo experiments conducted on HFD-induced NAFLD mice showed that treatment with NC-CS/PT-NPs inhibited weight gain, decreased serum aspartate aminotransferase (AST), Alanine aminotransferase (ALT) and lipid levels, improved liver and intestinal inflammation, and altered the diversity of gut microbiota in mice.

Conclusion

This study provides new evidence for the treatment of NAFLD through the regulation of gut microbiota using active ingredients from traditional Chinese medicine.

Multiomics analysis revealed the mechanism of the anti-diabetic effect of Salecan

Salecan, a natural β-glucan compromising nine residues connected by β-(1 → 3)/α-(1 → 3) glycosidic bonds, is one of the newly approved food ingredients. Salecan has multiple health-improving effects, yet its mechanism against Type 2 diabetes mellitus (T2DM) remains poorly understood. In this study, the hypoglycemic effect and underlying mechanism of Salecan intervention on STZ-induced diabetic model mice were investigated. After 8 weeks of gavage, Salecan attenuated insulin resistance and repaired pancreatic β cells in a dose-dependent manner. In addition, Salecan supplement remodel the structure of the gut microbiota and altered the level of intestinal metabolites. Serum metabolites, especially unsaturated fatty acids, were also affected significantly. In addition, tight junction proteins in the colon and autophagy-related proteins in the pancreas were upregulated. Multiomics analysis indicated that Lactobacillus johnsonii, Muribaculaceae, and Lachnoclostridium were highly associated with fatty acid esters of hydroxy fatty acids (FAHFA) levels in the colon, accordingly enhancing arachidonic acid and linoleic acid in serum, and promoting GLP-1 release in the intestine and insulin secretion in the pancreas, thus relieving insulin resistance and exhibiting hypoglycemic effects. These findings provide a novel understanding of the anti-diabetic effect of Salecan in mice from a molecular perspective, paving the way for the wide use of Salecan.

Integrated Analysis of Gut Microbiome and Adipose Transcriptome Reveals Beneficial Effects of Resistant Dextrin from Wheat Starch on Insulin Resistance in Kunming Mice

Systemic chronic inflammation is recognized as a significant contributor to the development of obesity-related insulin resistance. Previous studies have revealed the physiological benefits of resistant dextrin (RD), including obesity reduction, lower fasting glucose levels, and anti-inflammation. The present study investigated the effects of RD intervention on insulin resistance (IR) in Kunming mice, expounding the mechanisms through the gut microbiome and transcriptome of white adipose. In this eight-week study, we investigated changes in tissue weight, glucose-lipid metabolism levels, serum inflammation levels, and lesions of epididymal white adipose tissue (eWAT) evaluated via Hematoxylin and Eosin (H&E) staining. Moreover, we analyzed the gut microbiota composition and transcriptome of eWAT to assess the potential protective effects of RD intervention. Compared with a high-fat, high-sugar diet (HFHSD) group, the RD intervention significantly enhanced glucose homeostasis (e.g., AUC-OGTT, HOMA-IR, p < 0.001), and reduced lipid metabolism (e.g., TG, LDL-C, p < 0.001) and serum inflammation levels (e.g., IL-1β, IL-6, p < 0.001). The RD intervention also led to changes in the gut microbiota composition, with an increase in the abundance of probiotics (e.g., Parabacteroides, Faecalibaculum, and Muribaculum, p < 0.05) and a decrease in harmful bacteria (Colidextribacter, p < 0.05). Moreover, the RD intervention had a noticeable effect on the gene transcription profile of eWAT, and KEGG enrichment analysis revealed that differential genes were enriched in PI3K/AKT, AMPK, in glucose-lipid metabolism, and in the regulation of lipolysis in adipocytes signaling pathways. The findings demonstrated that RD not only ameliorated IR, but also remodeled the gut microbiota and modified the transcriptome profile of eWAT.

Study on the Anti-Ulcerative Colitis Effect of Pseudo-Ginsenoside RT4 Based on Gut Microbiota, Pharmacokinetics, and Tissue Distribution

The purpose of this study was to explore the therapeutic effect of the oral administration of pseudo-ginsenoside RT4 (RT4) on ulcerative colitis (UC), and to determine the rate of absorption and distribution of RT4 in mice with UC. Balb/c mice were induced using dextran sulfate sodium salts (DSS) to establish the UC model, and 10, 20, or 40 mg/kg of RT4 was subsequently administered via gavage. The clinical symptoms, inflammatory response, intestinal barrier, content of total short-chain fatty acids (SCFAs), and gut microbiota were investigated. Caco-2 cells were induced to establish the epithelial barrier damage model using LPS, and an intervention was performed using 4, 8, and 16 µg/mL of RT4. The inflammatory factors, transient electrical resistance (TEER), and tight-junction protein expression were determined. Finally, pharmacokinetic and tissue distribution studies following the intragastric administration of RT4 in UC mice were performed. According to the results in mice, RT4 decreased the disease activity index (DAI) score, restored the colon length, reduced the levels of pro-inflammatory cytokines (TNF-α, IL-6, and IL-1β), and boosted the levels of immunosuppressive cytokine IL-10, increased the content of SCFAs, improved the colonic histopathology, maintained the ultrastructure of colonic mucosal epithelial cells, and corrected disturbances in the intestinal microbiota. Based on the results in caco-2 cells, RT4 reduced the levels of TNF-α, IL-6, and IL-1β; protected integrity of monolayers; and increased tight-junction protein expression. Additionally, the main pharmacokinetic parameters (Cmax, Tmax, t1/2, Vd, CL, AUC) were obtained, the absolute bioavailability was calculated as 18.90% ± 2.70%, and the main distribution tissues were the small intestine and colon. In conclusion, RT4, with the features of slow elimination and directional distribution, could alleviate UC by inhibiting inflammatory factors, repairing the intestinal mucosal barrier, boosting the dominant intestinal microflora, and modulating the expression of SCFAs.

From Gut to Glucose: A Comprehensive Review on Functional Foods and Dietary Interventions for Diabetes Management

BACKGROUND

In the realm of diabetes research, considerable attention has been directed toward elucidating the intricate interplay between the gastrointestinal tract and glucose regulation. The gastrointestinal tract, once exclusively considered for its role in digestion and nutrient assimilation, is presently acknowledged as a multifaceted ecosystem with regulatory supremacy over metabolic homeostasis and glucose metabolism. Recent studies indicate that alterations in the composition and functionality of the gut microbiota could potentially influence the regulation of glucose levels and glucose homeostasis in the body. Dysbiosis, characterized by perturbations in the equilibrium of gut microbial constituents, has been irrevocably linked to an augmented risk of diabetes mellitus (DM). Moreover, research has revealed the potential influence of the gut microbiota on important factors, like inflammation and insulin sensitivity, which are key contributors to the onset and progression of diabetes. The key protagonists implicated in the regulation of glucose encompass the gut bacteria, gut barrier integrity, and the gut-brain axis. A viable approach to enhance glycemic control while concurrently mitigating the burden of comorbidities associated with diabetes resides in the strategic manipulation of the gut environment through adapted dietary practices.

OBJECTIVE

This review aimed to provide a deep understanding of the complex relationship between gut health, glucose metabolism, and diabetes treatment.

CONCLUSION

This study has presented an exhaustive overview of dietary therapies and functional foods that have undergone extensive research to explore their potential advantages in the management of diabetes. It looks into the role of gut health in glucose regulation, discusses the impact of different dietary elements on the course of diabetes, and evaluates how well functional foods can help with glycemic control. Furthermore, it investigates the mechanistic aspects of these therapies, including their influence on insulin sensitivity, β-cell activity, and inflammation. It deliberates on the limitations and potential prospects associated with integrating functional foods into personalized approaches to diabetes care.

Moderate altitude exposure impacts host fasting blood glucose and serum metabolome by regulation of the intestinal flora

Moderate altitude exposure has shown beneficial effects on diabetes incidence but the underlying mechanisms are not understood. Our study aimed to investigate how the human gut microbiome impacted the serum metabolome and associated with glucose homeostasis in healthy Chinese individuals upon moderate-altitude exposure. Faecal microbiome composition was assessed using shotgun metagenomic sequencing. Serum metabolome was acquired by untargeted metabolomics technology, and amino acids (AAs) and propionic acid in serum were quantified by targeted metabolomics technology. The results indicated that the moderate-altitude exposed individuals presented lowered fasting blood glucose (FBG) and propionic acid, increased circulating L-Glutamine but decreased L-Glutamate and L-Valine, which correlated with enriched Bacteroidetes and decreased Proteobacteria. Additionally, the silico causality associations among gut microbiota, serum metabolome and host FBG were analyzed by mediation analysis. It showed that increased Bacteroides ovatus (B. ovatus) and decreased Escherichia coli (E. coli) were identified as the main antagonistic species driving the association between L-Glutamate and FBG in silico causality. Furthermore, the high-fat diet (HFD) fed mice subjected to faecal microbiota transplantation (FMT) were applied to validate the cause-in-fact effects of gut microbiota on the beneficial glucose response. We found that microbiome in the moderate-altitude exposed donor could predict the extent of the FBG response in recipient mice, which showed lowered FBG, L-Glutamate and Firmicutes/Bacteroidetes ratio. Our findings suggest that moderate-altitude exposure targeting gut microbiota and circulating metabolome, may pave novel avenues to counter dysglycemia.

Translocation of gut microbes to epididymal white adipose tissue drives lipid metabolism disorder under heat stress

Heat stress induces multi-organ damage and serious physiological dysfunction in mammals, and gut bacteria may translocate to extra-intestinal tissues under heat stress pathology. However, whether gut bacteria translocate to the key metabolic organs and impair function as a result of heat stress remains unknown. Using a heat stress-induced mouse model, heat stress inhibited epididymal white adipose tissue (eWAT) expansion and induced lipid metabolic disorder but did not damage other organs, such as the heart, liver, spleen, or muscle. Microbial profiling analysis revealed that heat stress shifted the bacterial community in the cecum and eWAT but not in the inguinal white adipose tissue, blood, heart, liver, spleen, or muscle. Notably, gut-vascular barrier function was impaired, and the levels of some bacteria, particularly Lactobacillus, were higher in the eWAT, as confirmed by catalyzed reporter deposition fluorescence in situ hybridization (CARD-FISH) staining when mice were under heat stress. Moreover, integrated multi-omics analysis showed that the eWAT microbiota was associated with host lipid metabolism, and the expression of genes involved in the lipid metabolism in eWAT was upregulated under heat stress. A follow-up microbial supplementation study after introducing Lactobacillus plantarum to heat-stressed mice revealed that the probiotic ameliorated heat stress-induced loss of eWAT and dyslipidemia and reduced gut bacterial translocation to the eWAT by improving gut barrier function. Overall, our findings suggest that gut bacteria, particularly Lactobacillus spp., play a crucial role in heat stress-induced lipid metabolism disorder and that there is therapeutic potential for using probiotics, such as Lactobacillus plantarum.

Lower serum branched-chain amino acid catabolic intermediates are predictive signatures specific to patients with diabetic foot

Diabetic foot (DF) is one of the serious chronic complications of diabetes. Accurate prediction of the risk of DF may take timely intervention measures to prevent its occurrence. The understanding of metabolomic changes in the progression of diabetes to DF may reveal new targets for interventions. We hypothesized that changes in metabolic pathways during DF would lead to changes in the metabolic profile, which could be predictive signature specific to it. In the present study, 43 participants with type 2 diabetes mellitus (T2DM), 32 T2DM participants with DF (T2DM-F), and 36 healthy subjects were enrolled and their serum samples were used for targeted and nonpolar metabolic analysis with liquid chromatography-tandem mass spectrometry. Differential metabolites related to T2DM-F were discovered in metabolomic analysis. Lasso machine learning regression model, random forest algorithm, causal mediation analysis, disease risk assessment, and clinical decision model were carried out. T2DM and T2DM-F groups could be distinguished with the healthy control group. The differential metabolites were all enriched in alpha-linolenic acid and linoleic acid metabolic pathways including arachidonic acid, docosapentaenoic-acid 22N-6, and docosahexaenoic-acid, which were significantly lower in the T2DM and T2DM-F groups compared with the healthy control group. The differential metabolites in T2DM-F vs T2DM groups were enriched to branched-chain amino acid (BCAA) catabolic pathways involving in methylmalonic acid, succinic acid, 3-methyl-2-oxovaleric acid, and ketoleucine, which were the BCAA catabolic intermediates and significantly lower in the T2DM-F compared with the T2DM group except for succinic acid. We reveal a new set of predictive signatures and associate the lower BCAA catabolic intermediates with the progression from T2DM to T2DM-F.

The Emerging Role of Gut Microbiota in Age-Related Macular Degeneration

Age-related macular degeneration (AMD) is a progressive, degenerative retinal disease that is a leading cause of blindness globally. Although multiple risk factors have been identified regarding disease incidence and progression, including smoking, genetics, and diet, the understanding of AMD pathogenesis remains unclear. As such, primary prevention is lacking, and current treatments have limited efficacy. More recently, the gut microbiome has emerged as an influential player in various ocular pathologies. As mediators of metabolism and immune regulation, perturbations in gut microbiota may impart significant effects distally on the neuroretina and its adjacent tissues, termed the gut-retina axis. In this review, key studies over the past several decades are summarized, both in humans and in animal models, which shed insight on the relationships between the gut microbiome and retinal biology and their implications for AMD. The literature linking gut dysbiosis with AMD is examined, along with preclinical animal models and techniques apt for studying the role of gut microbiota in AMD pathogenesis, which include interactions with systemic inflammation, immune regulation, chorioretinal gene expression, and diet. As understanding of the gut-retina axis continues to advance, so too will the possibility for more accessible and effective prevention and therapy of this vision-threatening condition.

The causality between gut microbiome and liver cirrhosis: a bi-directional two-sample Mendelian randomization analysis

Background and aim

Previous studies have reported an association between gut microbiota and cirrhosis. However, the causality between intestinal flora and liver cirrhosis still remains unclear. In this study, bi-directional Mendelian randomization (MR) analysis was used to ascertain the potential causal effect between gut microbes and cirrhosis.

Methods

Large-scale Genome Wide Association Study (GWAS) data of cirrhosis and gut microbes were obtained from FinnGen, Mibiogen consortium, and a GWAS meta-analysis of Alcoholic cirrhosis (ALC). Two-sample MR was performed to determine the causal relationship between gut microbiota and cirrhosis. Furthermore, a bi-directional MR analysis was employed to examine the direction of the causal relations.

Result

In MR analysis, we found that 21 gut microbiotas were potentially associated with cirrhosis. In reverse MR analysis, 11 gut microbiotas displayed potentially associations between genetic liability in the gut microbiome and cirrhosis. We found that the family Lachnospiraceae (OR: 1.59, 95% CI:1.10-2.29) might be harmful in cirrhotic conditions (ICD-10: K74). Furthermore, the genus Erysipelatoclostridium might be a protective factor for cirrhosis (OR:0.55, 95% CI:0.34-0.88) and PBC (OR:0.68, 95% CI:0.52-0.89). Combining the results from the MR analysis and reverse MR analysis, we firstly identified the Genus Butyricicoccus had a bi-directional causal effect on PBC (Forward: OR: 0.37, 95% CI:0.15-0.93; Reverse: OR: 1.03, 95% CI:1.00-1.05).

Conclusion

We found a new potential causal effect between cirrhosis and intestinal flora and provided new insights into the role of gut microbiota in the pathological progression of liver cirrhosis.

Theabrownin inhibits obesity and non-alcoholic fatty liver disease in mice via serotonin-related signaling pathways and gut-liver axis

INTRODUCTION

Non-alcoholic fatty liver disease (NAFLD) with obesity seriously threats public health. Our previous studies showed that dark tea had more potential on regulating lipid metabolism than other teas, and theabrownin (TB) was considered to be a main contributor to the bioactivity of dark tea.

OBJECTIVES

This in vivo study aims to reveal the effects and molecular mechanisms of TB on NAFLD and obesity, and the role of the gut-liver axis is explored.

METHODS

The histopathological examinations, biochemical tests, and nuclear magnetic resonance were applied to evaluate the effects of TB on NAFLD and obesity. The untargeted metabolomics was used to find the key molecule for further exploration of molecular mechanisms. The 16S rRNA gene sequencing was used to assess the changes in gut microbiota. The antibiotic cocktail and fecal microbiota transplant were used to clarify the role of gut microbiota.

RESULTS

TB markedly reduced body weight gain (67.01%), body fat rate (62.81%), and hepatic TG level (51.35%) in the preventive experiment. Especially, TB decreased body weight (32.16%), body fat rate (42.56%), and hepatic TG level (42.86%) in the therapeutic experiment. The mechanisms of action could be the improvement of fatty acid oxidation, lipolysis, and oxidative stress via the regulation of serotonin-related signaling pathways. Also, TB increased the abundance of serotonin-related gut microbiota, such as Akkermansia, Bacteroides and Parabacteroides. Antibiotics-induced gut bacterial dysbiosis disrupted the regulation of TB on serotonin-related signaling pathways in liver, whereas the beneficial regulation of TB on target proteins was regained with the restoration of gut microbiota.

CONCLUSION

We find that TB has markedly preventive and therapeutic effects on NAFLD and obesity by regulating serotonin level and related signaling pathways through gut microbiota. Furthermore, gut microbiota and TB co-contribute to alleviating NAFLD and obesity. TB could be a promising medicine for NAFLD and obesity.

Dissecting the association between gut microbiota and liver cancer in European and East Asian populations using Mendelian randomization analysis

Background

Ample evidence suggests an important role of the gut microbiome in liver cancer, but the causal relationship between gut microbiome and liver cancer is unclear. This study employed Mendelian randomization (MR) analysis to examine the causal relationship between the gut microbiome and liver cancer in European and East Asian populations.

Methods

We sourced genetic variants linked to gut microbiota from the MiBioGen consortium meta-analysis, and procured liver cancer genome-wide association study (GWAS) summary data from the FinnGen consortium and Biobank Japan. We employed the inverse variance weighted method for primary statistical analysis, fortified by several sensitivity analyses such as MR-PRESSO, MR-Egger regression, weighted median, weighted mode, and maximum likelihood methods for rigorous results. We also evaluated heterogeneity and horizontal pleiotropy.

Results

The study examined an extensive set of gut microbiota, including 131 genera, 35 families, 20 orders, 16 classes, and 9 phyla. In Europeans, ten gut microbiota types displayed a suggestive association with liver cancer (p < 0.05). Notably, Oscillospira and Mollicutes RF9 exhibited a statistically significant positive association with liver cancer risk, with odds ratios (OR) of 2.59 (95% CI 1.36-4.95) and 2.03 (95% CI 1.21-3.40), respectively, after adjusting for multiple testing. In East Asians, while six microbial types demonstrated suggestive associations with liver cancer, only Oscillibacter displayed a statistically significant positive association (OR = 1.56, 95% CI 1.11-2.19) with an FDR < 0.05. Sensitivity analyses reinforced these findings despite variations in p-values.

Conclusion

This study provides evidence for a causal relationship between specific gut microbiota and liver cancer, enhancing the understanding of the role of the gut microbiome in liver cancer and may offer new avenues for preventive and therapeutic strategies.

Penthorum chinense Pursh improves type 2 diabetes mellitus via modulating gut microbiota in db/db mice

Penthorum chinense Pursh (P. chinense) has been traditionally used as hepatoprotective food and medicine for hundreds of years due to its significant antioxidant and anti-inflammatory activities. However, the efficacy and mechanisms of action of P. chinense in type 2 diabetes mellitus were not fully understood. In this study, we found that P. chinense extract (PCP) supplementation resulted in reduced body weight and hyperglycemia, improved pancreatic tissue injury and insulin sensitivity, and decreased inflammatory cytokines expression in spontaneously diabetic db/db mice. 16S rRNA gene sequencing of fecal samples showed that PCP administration decreased the abundance of Firmicutes and increased the proportion of Bacteroidetes at the phylum level. Moreover, Muribaculum, Barnesiella, Prevotella, and Mucinivorans were enriched, with Desulfovibrio and Lactobacillus lowered at the genus level in db/db mice with PCP supplementation. These results suggested that PCP may ameliorate hyperglycemia, insulin resistance, and inflammation by remodeling the gut microbiota in db/db mice.

The Crosstalk between Gut Microbiota and Bile Acids Promotes the Development of Non-Alcoholic Fatty Liver Disease

Recently the roles of gut microbiota are highly regarded in the pathogenesis of nonalcoholic fatty liver disease (NAFLD). The intestinal bacteria regulate the metabolism of bile acids depending on bile salt hydrolase (BSH), 7-dehydroxylation, hydroxysteroid dehydrogenase (HSDH), or amide conjugation reaction, thus exerting effects on NAFLD development through bile acid receptors such as farnesoid X receptor (FXR), Takeda G-protein-coupled bile acid protein 5 (TGR5), and vitamin D receptor (VDR), which modulate nutrient metabolism and insulin sensitivity via interacting with downstream molecules. Reversely, the composition of gut microbiota is also affected by the level of bile acids in turn. We summarize the mutual regulation between the specific bacteria and bile acids in NAFLD and the latest clinical research based on microbiota and bile acids, which facilitate the development of novel treatment modalities in NAFLD.

Bioinspired pH-Responsive Microalgal Hydrogels for Oral Insulin Delivery with Both Hypoglycemic and Insulin Sensitizing Effects

The oral form of insulin is more convenient and has better patient compliance than subcutaneous or intravenous insulin. Current oral insulin preparations, however, cannot overcome the enzyme barrier, chemical barrier, and epithelial barrier of the gastrointestinal tract completely. In this study, a microalgae-based oral insulin delivery strategy (CV@INS@ALG) was developed using Chlorella vulgaris (CV)-based insulin delivery system cross-linking with sodium alginate (ALG). CV@INS@ALG could overcome the gastrointestinal barrier, protect insulin from harsh gastric conditions, and achieve a pH-responsive drug release in the intestine. CV@INS@ALG might contribute to two mechanisms of insulin absorption, including direct insulin release from the delivery system and endocytosis by M cells and macrophages. In the streptozotocin (STZ)-induced type 1 diabetic mouse model, CV@INS@ALG showed a more effective and long-lasting hypoglycemic effect than direct insulin injection and did not cause any damage to the intestinal tract. Additionally, the long-term oral administration of the carrier CV@ALG effectively ameliorated gut microbiota disorder, and significantly increased the abundance of probiotic Akkermansia in db/db type 2 diabetic mice, thereby enhancing the insulin sensitivity of mice. Microalgal insulin delivery systems could be degraded and metabolized in the intestinal tract after oral administration, showing good biodegradability and biosafety. This insulin delivery strategy based on microalgal biomaterials provides a natural, efficient, and multifunctional solution for oral insulin delivery.

The Potential Cardiometabolic Effects of Long-Chain ω-3 Polyunsaturated Fatty Acids: Recent Updates and Controversies

Various health-related effects of long-chain (LC) ω-3 PUFAs, EPA, and DHA have been suggested. LC ω-3 PUFAs reduce TG concentrations and have anti-inflammatory, immunomodulatory, antiplatelet, and vascular protective effects. Controversially, they might help in restoring glucose homeostasis via the gut microbiota. However, previous studies have not shown the clear benefits of LC ω-3 PUFAs for CVDs. REDUCE-IT and STRENGTH-representative randomized controlled trials (RCTs) that examined whether LC ω-3 PUFAs would prevent major adverse cardiovascular (CV) events (MACE)-showed conflicting results with differences in the types, doses, or comparators of LC ω-3 PUFAs and study populations. Therefore, we performed a meta-analysis using major RCTs to address this inconsistency and assess the clinical and biological effects of LC ω-3 PUFAs. We included RCTs that involved ≥500 participants with ≥1 y follow-up. Of 17 studies involving 143,410 people, LC ω-3 PUFA supplementation showed beneficial effects on CV death (RR: 0.94; 95% CI: 0.88, 0.99; P = 0.029) and fatal or nonfatal MI (RR: 0.83; 95% CI: 0.72, 0.95; P = 0.010). RCTs on EPA alone showed better results for 3-point MACE, CV death, and fatal or nonfatal MI. However, the benefits were not found for fatal or nonfatal stroke, all-cause mortality, and hospitalization for heart failure. Of note, studies of both the EPA/DHA combination and EPA alone showed a significant increase in risk of new-onset atrial fibrillation. Thus, well-designed studies are needed to investigate the underlying mechanisms involved in the distinct effects of EPA compared with DHA on cardiometabolic diseases. This review discusses the potential benefits and safety of LC ω-3 PUFAs from a cardiometabolic perspective focusing on recent updates and controversies.

The Effects of Omega 3 and Omega 6 Fatty Acids on Glucose Metabolism: An Updated Review

Massive changes have occurred in our diet. A growing consumption of vegetal oils rich in omega-6 (ω-6) and a depletion of omega-3 (ω-3) fatty acids (FAs) in our food has led to an imbalance between ω-3 and ω-6. In particular, eicosapentaenoic (EPA)/arachidonic acid (AA) ratio seems to be an indicator of this derangement, whose reduction is associated to the development of metabolic diseases, such as diabetes mellitus. Our aim was therefore to investigate the literature on the effects of ω-3 and ω-6 FAs on glucose metabolism. We discussed emerging evidence from pre-clinical studies and from clinical trials. Notably, conflicting results emerged. Source of ω-3, sample size, ethnicity, study duration and food cooking method may be responsible for the lack of univocal results. High EPA/AA ratio seems to be a promising indicator of better glycemic control and reduced inflammation. On the other hand, linoleic acid (LA) appears to be also associated to a minor incidence of type 2 diabetes mellitus, although it is still not clear if the outcome is related to a reduced production of AA or to its intrinsic effect. More data derived from multicenter, prospective randomized clinical trials are needed.

Nanosecond pulse effectively ablated hepatocellular carcinoma with alterations in the gut microbiome and serum metabolites

Background: Hepatocellular carcinoma (HCC) is the third leading cause of cancer-related death in the world. Nanosecond pulsed electric fields (nsPEFs) have emerged as a new treatment for cancer. This study aims to identify the effectiveness of nsPEFs in the treatment of HCC and analyze the alterations in the gut microbiome and serum metabonomics after ablation. Methods: C57BL/6 mice were randomly divided into three groups: healthy control mice (n = 10), HCC mice (n = 10), and nsPEF-treated HCC mice (n = 23). Hep1-6 cell lines were used to establish the HCC model in situ. Histopathological staining was performed on tumor tissues. The gut microbiome was analyzed by 16S rRNA sequencing. Serum metabolites were analyzed by liquid chromatography-mass spectrometry (LC-MS) metabolomic analysis. Spearman's correlation analysis was carried out to analyze the correlation between the gut microbiome and serum metabonomics. Results: The fluorescence image showed that nsPEFs were significantly effective. Histopathological staining identified nuclear pyknosis and cell necrosis in the nsPEF group. The expression of CD34, PCNA, and VEGF decreased significantly in the nsPEF group. Compared with normal mice, the gut microbiome diversity of HCC mice was increased. Eight genera including Alistipes and Muribaculaceae were enriched in the HCC group. Inversely, these genera decreased in the nsPEF group. LC-MS analysis confirmed that there were significant differences in serum metabolism among the three groups. Correlation analysis showed crucial relationships between the gut microbiome and serum metabolites that are involved in nsPEF ablation of HCC. Conclusion: As a new minimally invasive treatment for tumor ablation, nsPEFs have an excellent ablation effect. The alterations in the gut microbiome and serum metabolites may participate in the prognosis of HCC ablation.

Polyunsaturated fatty acids-rich dietary lipid prevents high fat diet-induced obesity in mice

Diet is the primary factor affecting host nutrition and metabolism, with excess food intake, especially high-calorie diets, such as high-fat and high-sugar diets, causing an increased risk of obesity and related disorders. Obesity alters the gut microbial composition and reduces microbial diversity and causes changes in specific bacterial taxa. Dietary lipids can alter the gut microbial composition in obese mice. However, the regulation of gut microbiota and host energy homeostasis by different polyunsaturated fatty acids (PUFAs) in dietary lipids remains unknown. Here, we demonstrated that different PUFAs in dietary lipids improved host metabolism in high-fat diet (HFD)-induced obesity in mice. The intake of the different PUFA-enriched dietary lipids improved metabolism in HFD-induced obesity by regulating glucose tolerance and inhibiting colonic inflammation. Moreover, the gut microbial compositions were different among HFD and modified PUFA-enriched HFD-fed mice. Thus, we have identified a new mechanism underlying the function of different PUFAs in dietary lipids in regulating host energy homeostasis in obese conditions. Our findings shed light on the prevention and treatment of metabolic disorders by targeting the gut microbiota.

Empagliflozin ameliorates atherosclerosis via regulating the intestinal flora

BACKGROUND AND AIMS

Sodium-glucose cotransporter 2 inhibitor (SGLT2i) has been reported to attenuate atherosclerosis. Further, it has been suggested that intestinal flora influences atherosclerosis progression. Herein we aimed to investigate whether SGLT2i can alleviate atherosclerosis through intestinal flora.

METHODS

Six-week-old male ApoE^-/- mice fed a high-fat diet were gavaged either empagliflozin (SGLT2i group, n = 9) or saline (Ctrl group, n = 6) for 12 weeks. Feces were collected from both groups at the end of the experiment for fecal microbiota transplantation (FMT). Another 12 six-week-old male ApoE^-/- mice were fed a high-fat diet and received FMT with feces either from SGLT2i (FMT-SGLT2i group, n = 6) or from Ctrl (FMT-Ctrl group, n = 6) groups. Blood, tissue, and fecal samples were collected for subsequent analyses.

RESULTS

In comparison with Ctrl group, atherosclerosis was less severe in the SGLT2i group (p < 0.0001), and the richness of probiotic, such as f_Coriobacteriaceae, f_S24-7, f_Lachnospiraceae, and f_Adlercreutzia, was higher in feces. Besides, empagliflozin resulted in a significant reduction in the inflammatory response and altered intestinal flora metabolism. Interestingly, compared with FMT-Ctrl, FMT-SGLT2i also showed a reduction in atherosclerosis and systemic inflammatory response, as well as changes in the component of intestinal flora and pertinent metabolites similar to SGLT2i group.

CONCLUSIONS

Empagliflozin seems to mitigate atherosclerosis partly by regulating intestinal microbiota, and this anti-atherosclerotic effect can be transferred through intestinal flora transplantation.

Omega-3-Rich Fish-Oil-Influenced Mouse Gut Microbiome Shaped by Intermittent Consumption of Beef

Beef consumption can provide various amino acids, lipids, vitamins, and minerals; however, excessive intake causes metabolic disorders and increases the probability of obesity, atherosclerosis, and colorectal cancer. The intake of omega-3 fatty acids can ameliorate metabolic disorders by lowering blood glucose and triglyceride levels. In the present study, we investigated the effect of omega-3-rich fish oil on body performance and the gut microbiome in a beef-rich diet. Four-week-old C57BL/6 mice were distributed into four groups (chow diet [Chow], chow with beef diet [Beef], chow with omega-3 diet [Cw3], and chow with beef and omega-3 diet [Bw3]). We observed that body weight was unaltered between groups, and serum triglyceride levels were reduced in the omega-3 supplemented groups. The beta diversity indices, unweighted UniFrac distance (P = 0.001), and Jaccard distance (P = 0.001) showed statistically significant differences, and the principal coordinates analysis plot showed a clear separation between groups. In addition, the taxonomic comparison revealed that beef consumption increased numerous potentially pathogenic bacteria, including Escherichia-Shigella, Mucispirillum, Helicobacter, and Desulfovibrio, which were decreased following omega-3 supplementation. Metabolic comparison based on 16S rRNA revealed that energy and glucose metabolism were higher in omega-3 supplemented groups. Our findings suggest that the omega-3 supplementation under intermittent beef consumption contributes to changes in the gut microbiome and microbial metabolic pathways.

Intakes of omega-3 fatty acids and risks of all-cause and cause-specific mortality in people with diabetes: a cohort study based on NHANES 1999-2014

AIMS

Intake of omega-3 fatty acids is associated with several health benefits, but the specific benefits in populations with diabetes have yet to be elucidated. Therefore, this study aimed to explore the relationship between intake of omega-3 fatty acids and mortality in people with diabetes.

METHODS

This was a prospective cohort study and included 4854 participants with diabetes (mean age, 57.92 years; 50.9% male) from the National Health and Nutrition Examination Survey (1999-2014). Eicosapentaenoic (EPA) and docosahexaenoic (DHA) acid intake were used as alternative markers of omega-3 fatty acids intake and calculated based on the sum of the 24-h dietary recall interviews and dietary supplements. Mortality data were ascertained by linkage to National Death Index records by December 31, 2015. Cox proportional hazard models and restricted cubic spline were used to assess the relationship between EPA and DHA intake and all-cause and cause-specific mortality. Statistical analyses were performed using R 4.2.0 software.

RESULTS

Compared with participants with a lower EPA + DHA intake, participants who had a higher EPA + DHA intake tended to be Non-Hispanic Black; were more likely to be obese; and had higher daily energy intake and family income. During 34,386 person-years of follow-up, 1102 deaths were documented, including 266 cardiovascular disease deaths and 152 cancer deaths. In multivariable regression analyses with adjustment of confounding factors, higher EPA + DHA intake was significantly and linearly related to lower all-cause mortality: there was a 25% reduced risk of all-cause mortality.

CONCLUSIONS

Higher omega-3 fatty acid intake was independently related to lower all-cause mortality in individuals with diabetes, suggesting an adequate intake of omega-3 fatty acids may prevent premature death among the population with diabetes.

Metabolomics Analysis Reveals Novel Targets of Chemosensitizing Polyphenols and Omega-3 Polyunsaturated Fatty Acids in Triple Negative Breast Cancer Cells

Triple negative breast cancer (TNBC) is a subtype of breast cancer with typically poorer outcomes due to its aggressive clinical behavior and lack of targeted treatment options. Currently, treatment is limited to the administration of high-dose chemotherapeutics, which results in significant toxicities and drug resistance. As such, there is a need to de-escalate chemotherapeutic doses in TNBC while also retaining/improving treatment efficacy. Dietary polyphenols and omega-3 polyunsaturated fatty acids (PUFAs) have been demonstrated to have unique properties in experimental models of TNBC, improving the efficacy of doxorubicin and reversing multi-drug resistance. However, the pleiotropic nature of these compounds has caused their mechanisms to remain elusive, preventing the development of more potent mimetics to take advantage of their properties. Using untargeted metabolomics, we identify a diverse set of metabolites/metabolic pathways that are targeted by these compounds following treatment in MDA-MB-231 cells. Furthermore, we demonstrate that these chemosensitizers do not all target the same metabolic processes, but rather organize into distinct clusters based on similarities among metabolic targets. Common themes in metabolic targets included amino acid metabolism (particularly one-carbon and glutamine metabolism) and alterations in fatty acid oxidation. Moreover, doxorubicin treatment alone generally targeted different metabolites/pathways than chemosensitizers. This information provides novel insights into chemosensitization mechanisms in TNBC.

Integrated Proteomics and Metabolomics Analysis to Explore the Amelioration Mechanisms of Rosa roxburghii Tratt Fruit Polyphenols on Lipopolysaccharide-Induced Acute Lung Injury Mice

Acute lung injury (ALI) is the main cause of death for the elderly and children due to its high morbidity and mortality rates. Plant-derived functional foods are becoming increasingly important to the healthcare and food industries for adjunctive and alternative treatments of ALI. Polyphenols have been regarded to be beneficial to the prevention and amelioration of ALI. Rosa roxburghii Tratt fruit polyphenols (RRTP) has potential to prevent ALI, but mechanism remains unclear. This study was set up to systematically analyze the RRTP extract active ingredients, comprehensively evaluate its protective effects via lung histopathological examination, protein concentration, and cytokines production in ALI mice induced by lipopolysaccharide (LPS), and finally revealed alleviation mechanisms of the regulatory effects of RRTP by proteomics and metabolomics approach. The results demonstrated RRTP could synergistically exert significant preventive effects against ALI by notably ameliorating lung histopathological damage and pulmonary capillary permeability in ALI mice, inhibiting lung tissue inflammatory response and acute phase proteins and S-100 calcium binding proteins, suppressing excessive activation of complement and coagulation cascades, and regulating disordered lipids metabolism and amino acid metabolism. This study illustrated that RRTP has obvious advantages in ALI adjunctive therapy and revealed the complicated amelioration mechanisms, which provides a breakthrough for the development and demonstration of RRTP as a nutritional compound additive for complementary therapy of ALI.

Microbiome-Metabolomics Analysis of the Impacts of Cryptosporidium muris Infection in BALB/C Mice

Cryptosporidium is a leading cause of diarrheal disease and mortality in young children worldwide. Cryptosporidium invades small intestinal epithelial cells and forms a unique intracellular niche, a process that may alter gut microbes and their production metabolites. However, the mechanism of interactions between gut microbes, metabolites, and parasites is poorly understood. Here, we first characterized the impacts of Cryptosporidium infection on gut microbiota using a microbiome-to-metabolome association study. BALB/c mice were gavaged with Cryptosporidium muris, and fecal samples were collected at 0, 7, 14, 21, and 28 days postinfection (dpi) to observe changes in the intestinal microbes of the body during parasite infection. The infected group had a significantly increased relative abundance of bacterial taxa, such as Lachnospiraceae and Prevotella (P < 0.05), associated with the biosynthesis of short-chain fatty acids (SCFAs). Metabolites related to the metabolic pathways, steroid hormone biosynthesis, and biosynthesis of unsaturated fatty acids pathway were upregulated at 7 dpi, indicating that related metabolites in the biosynthesis of unsaturated fatty acids may be essential for C. muris reproduction in vivo. The metabolites involved in metabolic pathways, bile secretion, and primary bile acid biosynthesis were upregulated at 14 dpi, and we speculate that these metabolites may be critical to the growth and development of Cryptosporidium oocysts in the host. Correlation analysis revealed that Firmicutes bacteria are significantly associated with α-linolenic acid metabolism pathways (P< 0.05). The gut microbiota changes dynamically, and the metabolites involved in fatty acid and bile acid biosynthesis may play important roles during cryptosporidiosis. Details of the gut microbiota and the metabolome after infection with Cryptosporidium may aid in the discovery of specific diagnostic markers and help us understand the changes in parasite metabolic pathways. IMPORTANCE Cryptosporidiosis is a gastrointestinal disease in humans and animals caused by the protozoan parasite Cryptosporidium. Control and treatment of the disease is challenging due to the lack of sensitive diagnostic tools and effective chemotherapy. The dynamics of gut microbiota and metabolites during Cryptosporidium infection may be the key to finding drugs and targets for parasite infection control. Our results indicate that C. muris infection can disrupt gut microbiota and metabolites, resulting in decreased bacterial abundance at the parasitic site. Unsaturated fatty acid pathway biosynthesis-related metabolites are significantly elevated at the patent period. Interestingly, the metabolite pathway that significantly elevated during peak parasite growth was bile acid, the metabolites of which may be important for the circulation of infection of Cryptosporidium oocysts in the host. The enhancing effects of short-chain fatty acid and bile acid metabolism on the growth and development of Cryptosporidium proposed in this study may provide a theoretical basis for future research on novel drugs and vaccines against this intestinal parasite.

The gut odorant receptor and taste receptor make sense of dietary components: A focus on gut hormone secretion

Odorant receptors (ORs) and taste receptors (TRs) are expressed primarily in the nose and tongue in which they transduce electrical signals to the brain. Advances in deciphering the dietary component-sensing mechanisms in the nose and tongue prompted research on the role of gut chemosensory cells. Acting as the pivotal interface between the body and dietary cues, gut cells "smell" and "taste" dietary components and metabolites by taking advantage of chemoreceptors-ORs and TRs, to maintain physiological homeostasis. Here, we reviewed this novel field, highlighting the latest discoveries pertinent to gut ORs and TRs responding to dietary components, their impacts on gut hormone secretion, and the mechanisms involved. Recent studies indicate that gut cells sense dietary components including fatty acid, carbohydrate, and phytochemical by activating relevant ORs, thereby modulating GLP-1, PYY, CCK, and 5-HT secretion. Similarly, gut sweet, umami, and bitter receptors can regulate the gut hormone secretion and maintain homeostasis in response to dietary components. A deeper understanding of the favorable influence of dietary components on gut hormone secretion via gut ORs and TRs, coupled with the facts that gut hormones are involved in diverse physiological or pathophysiological phenomena, may ultimately lead to a promising treatment for various human diseases.

Vitamin D alleviates non-alcoholic fatty liver disease via restoring gut microbiota and metabolism

Background

Non-alcoholic fatty liver disease (NAFLD) represents a severe public health problem. Dysbiosis of gut microbiome has been identified as one of the key environmental factors contributing to NAFLD. As an essential nutrition, Vitamin D (VD) plays an important role in regulating gut microbiota based on its receptor (Vitamin D Receptor, VDR) which is highly expressed in the gastrointestinal tract.

Methods

Rats were fed with HFD (high-fat diet) for 12 weeks. And the rats were treated with VD two times a week by intraperitoneal injection for 12 weeks. H&E staining combined with plasma biochemical index was performed to characterize pathological changes and function of the liver. Fecal microbiota 16S rRNA gene sequencing and metabolomics were taken to reveal the altered gut microbiota and metabolites.

Result

The VD alleviates the HFD-induced lipid accumulation in the liver as well as decreases the levels of amlodipine besylate (ALT) and amlodipine aspartate (AST). VD supplement decreased the ratio of phylum Firmicutes/Bacteroidetes (F/B) but increased alpha diversity. In addition, the VD treatment improved the HFD-induced gut microbiota by increasing the Prevotella and Porphyromonadaceae and decreasing Mucispirillum, Acetatifactor, Desulfovibrio, and Oscillospira abundance. Furthermore, the capability of tyrosine metabolism, tryptophan metabolism, arginine biosynthesis, and sphingolipid metabolism was enhanced after VD treatment. Consistently, Prevotella positively correlated with tryptophan metabolism and sphingolipid metabolism. Importantly, the Prevotella abundance was positively associated with serotonin, melatonin, tryptamine, L-arginine, and 3-dehydrosphinganine which synthesize from tryptophan, tyrosine, arginosuccinate, and serine, respectively.

Conclusion

VD treatment inhibited HFD-induced NAFLD accompany by dysbiosis gut microbiota and metabolites, suggesting that VD supplement could be a potential intervention used for NAFLD treatment by targeting the specific microbiota.

The plasma phospholipidome of the bottlenose dolphin (Tursiops truncatus) is modulated by both sex and developmental stage

Lipidomics represent a valid complementary tool to the biochemical analysis of plasma in humans. However, in cetaceans, these tools have been unexplored. Here, we evaluated how the plasma lipid composition of Tursiops truncatus is modulated by developmental stage and sex, aiming at a potential use of lipidomics in integrated strategies to monitor cetacean health. We characterized the fatty acid profile and detected a total of 26 fatty acids in T. truncatus plasma. The most abundant fatty acids were palmitic acid (C16:0), stearic acid (C18:0) and oleic acid (C18:1n-9). Interestingly, there are consistent differences between the fatty acid profile of mature female and mature male specimens. Phospholipidome analysis identified 320 different lipid species belonging to phosphatidylcholine (PC, 105 lipid species), lysophosphatidylcholine (42), phosphatidylethanolamine (PE, 67), lysophosphatidylethanolamine (18), phosphatidylglycerol (14), lysophosphatidylglycerol (8), phosphatidylinositol (14), lysophosphatidylinositol (2), phosphatidylserine (3), sphingomyelin (45) and ceramides (2) classes. The statistical analysis of the phospholipidome showed that its composition allows discriminating mature animals between sexes and mature males from immature males. Notably, discrimination between sexes is mainly determined by the contents of PE plasmalogens and lysophospholipids (LPC and LPE), while the differences between mature and immature male animals were mainly determined by the levels of PC lipids. This is the first time that a correlation between developmental stage and sex and the lipid composition of the plasma has been established in cetaceans. Being able to discern between age and sex-related changes is an encouraging step towards using these tools to also detect differences related to disease/dysfunction processes.

Dietary additive octyl and decyl glycerate modulates metabolism and inflammation under different dietary patterns with the contribution of the gut microbiota

Octyl and decyl glycerate (ODG), a medium-chain triglyceride (MCT), is widely used as a food additive. Medium-chain monoglycerides, such as glycerol monolaurate and glycerol monocaprylate, were found to change the composition of the gut microbiota and influence glucose and lipid metabolism and inflammation. However, whether ODG influences the gut microbiota and whether the alteration in the gut microbiota contributes to the metabolic phenotype remain unknown. Under a normal-chow diet, mice were treated with or without different dosages of ODG (150, 800, 1600 mg kg^-1) for 22 weeks. All doses of ODG significantly decreased the ratio of HDL to LDL cholesterol, improved the inflammation and insulin resistance, and increased the α-diversity of the gut microbiota and the abundance of Bifidobacterium and Turicibacter. Under a high-fat diet, mice were treated with or without 1600 mg kg^-1 ODG for 16 weeks. The results demonstrated that ODG significantly alleviated the increase in the ratio of HDL to LDL cholesterol, insulin resistance, and inflammation caused by HFD. The expression of related genes was consistent with the above observations. ODG also altered the composition of the gut microbiota and increased the Bifidobacterium abundance under HFD. Our findings indicated that ODG similarly improved glucose metabolism and inflammation but exhibited differential effects on lipid metabolism under different dietary patterns. Furthermore, changes in the gut microbiota caused by ODG supplementation might contribute to the alteration in glucose and lipid metabolism and inflammation, which might be influenced by dietary patterns.

Mechanisms of gut microbiota-immune-host interaction on glucose regulation in type 2 diabetes

Intestinal absorption of food is one of the sources of glucose. Insulin resistance and impaired glucose tolerance caused by lifestyle and diet are the precursors of type 2 diabetes. Patients with type 2 diabetes have trouble controlling their blood sugar levels. For long-term health, strict glycemic management is necessary. Although it is thought to be well correlated with metabolic diseases like obesity, insulin resistance, and diabetes, its molecular mechanism is still not completely understood. Disturbed microbiota triggers the gut immune response to reshape the gut homeostasis. This interaction not only maintains the dynamic changes of intestinal flora, but also preserves the integrity of the intestinal barrier. Meanwhile, the microbiota establishes a systemic multiorgan dialog on the gut-brain and gut-liver axes, intestinal absorption of a high-fat diet affects the host's feeding preference and systemic metabolism. Intervention in the gut microbiota can combat the decreased glucose tolerance and insulin sensitivity linked to metabolic diseases both centrally and peripherally. Moreover, the pharmacokinetics of oral hypoglycemic medications are also influenced by gut microbiota. The accumulation of drugs in the gut microbiota not only affects the drug efficacy, but also changes the composition and function of them, thus may help to explain individual therapeutic variances in pharmacological efficacy. Regulating gut microbiota through healthy dietary patterns or supplementing pro/prebiotics can provide guidance for lifestyle interventions in people with poor glycemic control. Traditional Chinese medicine can also be used as complementary medicine to effectively regulate intestinal homeostasis. Intestinal microbiota is becoming a new target against metabolic diseases, so more evidence is needed to elucidate the intricate microbiota-immune-host relationship, and explore the therapeutic potential of targeting intestinal microbiota.

N-3 PUFA Deficiency Aggravates Streptozotocin-Induced Pancreatic Injury in Mice but Dietary Supplementation with DHA/EPA Protects the Pancreas via Suppressing Inflammation, Oxidative Stress and Apoptosis

It has been reported that dietary n-3 polyunsaturated fatty acids (n-3 PUFAs) exert therapeutic potential for the preservation of functional β-cell mass. However, the effect of dietary n-3 PUFA deficiency on pancreatic injury and whether the supplementation of n-3 PUFA could prevent the development of pancreatic injury are still not clear. In the present study, an n-3 PUFA deficiency mouse model was established by feeding them with n-3 PUFA deficiency diets for 30 days. Results showed that n-3 PUFA deficiency aggravated streptozotocin (STZ)-induced pancreas injury by reducing the insulin level by 18.21% and the HOMA β-cell indices by 31.13% and the area of islet by 52.58% compared with the STZ group. Moreover, pre-intervention with DHA and EPA for 15 days could alleviate STZ-induced pancreas damage by increasing the insulin level by 55.26% and 44.33%, the HOMA β-cell indices by 118.81% and 157.26% and reversed the area of islet by 196.75% and 205.57% compared to the n-3 Def group, and the effects were significant compared to γ-linolenic acid (GLA) and alpha-linolenic acid (ALA) treatment. The possible underlying mechanisms indicated that EPA and DHA significantly reduced the ration of n-6 PUFA to n-3 PUFA and then inhibited oxidative stress, inflammation and islet β-cell apoptosis levels in pancreas tissue. The results might provide insights into the prevention and alleviation of pancreas injury by dietary intervention with PUFAs and provide a theoretical basis for their application in functional foods.