Influence of Maternal Inulin-Type Prebiotic Intervention on Glucose Metabolism and Gut Microbiota in the Offspring of C57BL Mice

Maternal inulin alleviates high-fat diet-induced lipid disorder in offspring by epigenetically modulating hypothalamus feeding circuit-related genes

Increasing evidence supports the existence of fetal-originated adult diseases. Recent research indicates that the intrauterine environment affects the fetal hypothalamic energy intake center. Inulin is a probiotic that can moderate metabolic disorders, but whether maternal inulin intervention confers long-term metabolic benefits to lipid metabolism in offspring in their adult lives and the mechanism involved are unknown. Here, we used a maternal overnutrition model that was induced by excess energy intake before and during pregnancy and lactation and maternal inulin intervention was performed during pregnancy and lactation. The hypothalamic genome methylation in offspring was analyzed using a methylation array. The results showed that maternal inulin treatment modified the maternal high-fat diet (HFD)-induced increases in body weight, adipose tissue weight, and serum insulin and leptin levels and decreases in serum adiponectin levels. Maternal inulin intervention regulated the impairments in hypothalamic leptin resistance, induced the methylation of Socs3, Npy, and Il6, and inhibited the methylation of Lepr in the hypothalamus of offspring. In conclusion, maternal inulin intervention modifies offspring lipid metabolism, and the underlying mechanism involves the methylation of genes in the hypothalamus feeding circuit.

The Combinational Effect of Inulin and Resveratrol on the Oxidative Stress and Inflammation Level in a Rat Model of Diabetic Nephropathy

Background

Using inulin can enhance resveratrol's effects by improving the intestinal microbiome and the stability of resveratrol.

Objectives

We aimed to investigate the effect of therapeutic intervention with combined inulin and resveratrol on kidney function in diabetic rats.

Methods

Diabetic model was induced by intraperitoneal injection of streptozotocin. Afterward, rats were divided into 6 groups: control, diabetic without treatment, diabetic treated with insulin, diabetic treated with resveratrol, diabetic treated with inulin, and diabetic treated with a combination of inulin and resveratrol. After 10 wk, the creatinine, urea, insulin, urinary proteins, and inflammatory and oxidative stress markers were evaluated. Pathologic changes were examined in kidney tissues.

Results

Renal dysfunction, accompanied by increased inflammation and oxidative stress, was observed. Our results showed that treatment with resveratrol and inulin had antidiabetic effects and was associated with reduced renal dysfunction, oxidative stress, and kidney inflammation. In addition, it was observed that combined treatment with inulin and resveratrol outperformed monotherapies in improving kidney function and reducing oxidative stress and inflammation.

Conclusions

Treatment with resveratrol and inulin can have renoprotective effects by improving oxidative stress and inflammation in kidney tissues. Therefore, employing these 2 compounds is suggested as an inexpensive and available method for diabetic nephropathy.

The microbiome's fiber degradation profile and its relationship with the host diet

BACKGROUND

The relationship between the gut microbiome and diet has been the focus of numerous recent studies. Such studies aim to characterize the impact of diet on the composition of the microbiome, as well as the microbiome's ability to utilize various compounds in the diet and produce metabolites that may be beneficial for the host. Consumption of dietary fibers (DFs)-polysaccharides that cannot be broken down by the host's endogenous enzymes and are degraded primarily by members of the microbiome-is known to have a profound effect on the microbiome. Yet, a comprehensive characterization of microbiome compositional and functional shifts in response to the consumption of specific DFs is still lacking.

RESULTS

Here, we introduce a computational framework, coupling metagenomic sequencing with careful annotation of polysaccharide degrading enzymes and DF structures, for inferring the metabolic ability of a given microbiome sample to utilize a broad catalog of DFs. We demonstrate that the inferred fiber degradation profile (IFDP) generated by our framework accurately reflects the dietary habits of various hosts across four independent datasets. We further demonstrate that IFDPs are more tightly linked to the host diet than commonly used taxonomic and functional microbiome-based profiles. Finally, applying our framework to a set of ~700 metagenomes that represents large human population cohorts from 9 different countries, we highlight intriguing global patterns linking DF consumption habits with microbiome capacities.

CONCLUSIONS

Combined, our findings serve as a proof-of-concept for the use of DF-specific analysis for providing important complementary information for better understanding the relationship between dietary habits and the gut microbiome.

The dynamic effects of maternal high-calorie diet on glycolipid metabolism and gut microbiota from weaning to adulthood in offspring mice

Dysbiosis of gut microbiota can contribute to the progression of diabetes and obesity. Previous studies have shown that maternal high-fat (HF) diet during the perinatal period can alter the microbiota and induce metabolic disorders at weaning. However, whether dysbiosis of gut microbiota and metabolism could be recovered by a normal diet after weaning and the dynamic changes of gut microbiota have not been fully studied. In this study, C57BL/6J female mice were fed with a normal chow (NC) or HF diet for 4 weeks preconception, during gestation, and until pup weaning. After weaning, male offspring were fed with an NC diet until 9 weeks of age. The microbiota of offspring at weaning and 9 weeks of age was collected for 16S rRNA gene amplicon sequencing. We found that dams fed with an HF diet showed glucose intolerance after lactation. Compared with the offspring from NC dams, the offspring from HF dams exhibited a higher body weight, hyperglycemia, glucose intolerance, hyperinsulinemia, hypercholesterolemia, and leptin resistance and lower adiponectin at weaning. Fecal analysis indicated altered microbiota composition between the offspring of the two groups. The decrease in favorable bacteria (such as norank f Bacteroidales S24-7 group) and increase in unfavorable bacteria (such as Lachnoclostridium and Desulfovibrio) were strongly associated with a disturbance of glucose and lipid metabolism. After 6 weeks of normal diet, no difference in body weight, glucose, and lipid profiles was observed between the offspring of the two groups. However, the microbiota composition of offspring in the HF group was still different from that in the NC group, and microbiota diversity was lower in offspring of the HF group. The abundance of Lactobacillus was lower in the offspring of the HF group. In conclusion, a maternal HF diet can induce metabolic homeostasis and gut microbiota disturbance in offspring at weaning. Gut microbiota dysbiosis can persist into adulthood in the offspring, which might have a role in the promotion of susceptibility to obesity and diabetes in the later life of the offspring.

The impact of maternal high-fat diet on offspring neurodevelopment

A maternal high-fat diet affects offspring neurodevelopment with long-term consequences on their brain health and behavior. During the past three decades, obesity has rapidly increased in the whole human population worldwide, including women of reproductive age. It is known that maternal obesity caused by a high-fat diet may lead to neurodevelopmental disorders in their offspring, such as autism spectrum disorder, attention deficit hyperactivity disorder, anxiety, depression, and schizophrenia. A maternal high-fat diet can affect offspring neurodevelopment due to inflammatory activation of the maternal gut, adipose tissue, and placenta, mirrored by increased levels of pro-inflammatory cytokines in both maternal and fetal circulation. Furthermore, a maternal high fat diet causes gut microbial dysbiosis further contributing to increased inflammatory milieu during pregnancy and lactation, thus disturbing both prenatal and postnatal neurodevelopment of the offspring. In addition, global molecular and cellular changes in the offspring's brain may occur due to epigenetic modifications including the downregulation of brain-derived neurotrophic factor (BDNF) expression and the activation of the endocannabinoid system. These neurodevelopmental aberrations are reflected in behavioral deficits observed in animals, corresponding to behavioral phenotypes of certain neurodevelopmental disorders in humans. Here we reviewed recent findings from rodent models and from human studies to reveal potential mechanisms by which a maternal high-fat diet interferes with the neurodevelopment of the offspring.

Natural Garlic Organosulfur Compounds Prevent Metabolic Disorder of Lipid and Glucose by Increasing Gut Commensal Bacteroides acidifaciens

A number of reports of the effects of garlic on gut microbiota revealed that the active garlic organosulfur compounds (OSCs) are destabilized by the action of alliinase during garlic preparation. In this study, garlic alliinase was deactivated to obtain stable garlic OSCs. Experiments with C57BL/6J mice fed with lipid and glucose metabolic disorder-inducing Western diet (WD) revealed that stable garlic OSCs prevented the disorder by increasing the relative abundance of gut Bacteroides acidifaciens. Molecular analysis indicated that garlic OSCs inhibited dyslipidemia and fatty liver by increasing taurine and subsequently promoting hepatic fatty acid β-oxidation. In parallel, garlic OSCs could meliorate glucose homeostasis by inhibiting dipeptidyl peptidase-4 (DPP-4) and hepatic gluconeogenesis. In vitro bacterial culture experiments revealed that garlic OSCs directly increased the growth of gut Bacteroides acidifaciens. The results of this study demonstrate that the molecular mechanism of the preventive effect of garlic OSCs on the WD-induced metabolic disorder is attributed to the enhanced growth of Bacteroides acidifaciens and the consequent increase in taurine.

The Potential of Prebiotic and Probiotic Supplementation During Obese Pregnancy to Improve Maternal and Offspring’s Metabolic Health and Reduce Obesity Risk—A Narrative Review

Worldwide, obesity prevalence is rising, severely impairing the health of those affected by increasing their risk for developing non-communicable diseases. The pathophysiology of obesity is complex and caused by a variety of genetic and environmental factors. Recent findings suggest that obesity is partly caused by dysbiosis, an imbalanced gut microbiome. In the context of pregnancy, maternal dysbiosis increases the child’s obesity risk, causing an intergenerational cycle of obesity. Accordingly, interventions modulating the gut microbiome have the potential to interrupt this cycle. This review discusses the potential of pre- and probiotic interventions in modulating maternal obesity associated dysbiosis to limit the child’s obesity risk. The literature search resulted in four animal studies using prebiotics as well as one animal study and six human studies using probiotics. Altogether, prebiotic supplementation in animals successfully decreased the offspring’s obesity risk, while probiotic supplementation in humans failed to show positive impacts in the offspring. However, comparability between studies is limited and considering the complexity of the topic, more studies in this field are required.

Gut microbiota and short chain fatty acids partially mediate the beneficial effects of inulin on metabolic disorders in obese ob/ob mice

Mounting evidence has linked both obesity and metabolic disorders with dysbiosis of the gut microbiota. Dietary inulin is conducive to modulating this dysbiosis, and represents a potential means to improve disorders of glucose and lipid metabolism. However, the mechanisms underlying these improvements are largely unclear. Obese ob/ob mice were fed a standard chow, a low fiber diet (LFD) or a high fiber diet (HFD) for 4 weeks, and the body weight, fecal short chain fatty acids (SCFAs) level, and plasma and liver lipid profiles were analyzed. Oral glucose tolerance testing, and gut microbiota sequencing were also conducted. Dietary inulin improved the dysbiosis of the gut microbiota, attenuated the decrease in phylum Bacteroidetes, repressed the increase of phylum Firmicutes, and led to an increase in the ratio of Firmicutes/Bacteroidetes. At the family level, inulin promoted the expansion of SCFAs-producing Ruminococcaceae and Lachnospiraceae bacteria, which increased the fecal SCFAs concentrations. At the genus level, inulin increased the levels of Bacteroides and Bifidobacteria. Furthermore, our results revealed that there was enhanced expression of angiopoietin-like protein 4 (ANGPTL4), which might be induced by the higher production of SCFAs, and this may underlie the improvements in the disorders of glucose and lipid metabolism seen in mice with added dietary inulin. In conclusion, inulin may ameliorate metabolic disorders by remodeling the gut microbiota and increasing the production of SCFAs, which might be mediated by the ANGPTL4-related signaling pathway. Interventions targeting the gut microbiota warrant further investigation as a novel therapy for metabolic diseases. PRACTICAL APPLICATIONS: Mounting evidence has linked both obesity and metabolic disorders with dysbiosis of the gut microbiota. Dietary inulin is conducive to modulating this dysbiosis, and represents a potential means to improve disorders of glucose and lipid metabolism. However, the mechanisms underlying these improvements are largely unclear. In the present study, we investigated the effects of dietary fiber (inulin) on metabolic homeostasis using ob/ob mice. The results of our study demonstrate that inulin-induced remodeling of the gut microbiota resulted in increased production of short chain fatty acids (SCFAs), leading to the enhanced expression of angiopoietin-like protein 4 (ANGPTL4), which improved the glucose and lipid metabolism. Our results suggest that the gut microbiota, SCFAs and ANGPTL4 pathway at least partially mediate the beneficial effects of inulin on metabolic disorders in ob/ob mice.

Activation of ectopic olfactory receptor 544 induces GLP-1 secretion and regulates gut inflammation

Olfactory receptors are ectopically expressed in extra-nasal tissues. The gut is constantly exposed to high levels of odorants where ectopic olfactory receptors may play critical roles. Activation of ectopic olfactory receptor 544 (Olfr544) by azelaic acid (AzA), an Olfr544 ligand, reduces adiposity in mice fed a high-fat diet (HFD) by regulating fuel preference to fats. Herein, we investigated the novel function of Olfr544 in the gut. In GLUTag cells, AzA induces the cAMP-PKA-CREB signaling axis and increases the secretion of GLP-1, an enteroendocrine hormone with anti-obesity effects. In mice fed a HFD and orally administered AzA, GLP-1 plasma levels were elevated in mice. The induction of GLP-1 secretion was negated in cells with Olfr544 gene knockdown and in Olfr544-deficient mice. Gut microbiome analysis revealed that AzA increased the levels of Bacteroides acidifaciens and microbiota associated with antioxidant pathways. In fecal metabolomics analysis, the levels of succinate and trehalose, metabolites correlated with a lean phenotype, were elevated by AzA. The function of Olfr544 in gut inflammation, a key feature in obesity, was further investigated. In RNA sequencing analysis, AzA suppressed LPS-induced activation of inflammatory pathways and reduced TNF-α and IL-6 expression, thereby improving intestinal permeability. The effects of AzA on the gut metabolome, microbiome, and colon inflammation were abrogated in Olfr544-KO mice. These results collectively demonstrated that activation of Olfr544 by AzA in the gut exerts multiple effects by regulating GLP-1 secretion, gut microbiome and metabolites, and colonic inflammation in anti-obesogenic phenotypes and, thus, may be applied for obesity therapeutics.

Diet-induced dysbiosis of the maternal gut microbiome in early life programming of neurodevelopmental disorders

The maternal gut microbiome plays a critical role in fetal and early postnatal development, shaping fundamental processes including immune maturation and brain development, among others. Consequently, it also contributes to fetal programming of health and disease. Over the last decade, epidemiological studies and work in preclinical animal models have begun to uncover a link between dysbiosis of the maternal gut microbiome and neurodevelopmental disorders in offspring. Neurodevelopmental disorders are caused by both genetic and environmental factors, and their interactions; however, clinical heterogeneity, phenotypic variability, and comorbidities make identification of underlying mechanisms difficult. Among environmental factors, exposure to maternal obesity in utero confers a significant increase in risk for neurodevelopmental disorders. Obesogenic diets in humans, non-human primates, and rodents induce functional modifications in maternal gut microbiome composition, which animal studies suggest are causally related to adverse mental health outcomes in offspring. Here, we review evidence linking maternal diet-induced gut dysbiosis to neurodevelopmental disorders and discuss how it could affect pre- and early postnatal brain development. We are hopeful that this burgeoning field of research will revolutionize antenatal care by leading to accessible prophylactic strategies, such as prenatal probiotics, to improve mental health outcomes in children affected by maternal diet-induced obesity.

Compositional change of gut microbiome and osteocalcin expressing endothelial progenitor cells in patients with coronary artery disease

Osteogenic endothelial progenitor cells (EPCs) contribute to impaired endothelial repair and promote coronary artery disease (CAD) and vascular calcification. Immature EPCs expressing osteocalcin (OCN) has been linked to unstable CAD; however, phenotypic regulation of OCN-expressing EPCs is not understood. We hypothesized that gut-microbiome derived pro-inflammatory substance, trimethylamine N-oxide (TMAO) might be associated with mobilization of OCN-expressing EPCs. This study aimed to investigate the association between dysbiosis, TMAO, and circulating mature and immature OCN-expressing EPCs levels in patients with and without CAD. We included 202 patients (CAD N = 88; no CAD N = 114) who underwent assessment of EPCs using flow cytometry and gut microbiome composition. Mature and immature EPCs co-staining for OCN were identified using cell surface markers as CD34+/CD133-/kinase insert domain receptor (KDR)+ and CD34-/CD133+/KDR+ cells, respectively. The number of observed operational taxonomy units (OTU), index of microbial richness, was used to identify patients with dysbiosis. The number of immature OCN-expressing EPCs were higher in patients with CAD or dysbiosis than patients without. TMAO levels were not associated with circulating levels of OCN-expressing EPCs. The relative abundance of Ruminococcus gnavus was moderately correlated with circulating levels of immature OCN-expressing EPCs, especially in diabetic patients. Gut dysbiosis was associated with increased levels of TMAO, immature OCN-expressing EPCs, and CAD. The relative abundance of Ruminococcus gnavus was correlated with immature OCN-expressing EPCs, suggesting that the harmful effects of immature OCN-expressing EPCs on CAD and potentially vascular calcification might be mediated by gut microbiome-derived systemic inflammation.

Dietary Supplementation with Inulin Modulates the Gut Microbiota and Improves Insulin Sensitivity in Prediabetes

AIMS

Accumulating evidence indicates gut microbiota dysbiosis is involved in metabolic disorders, including prediabetes. The prebiotic inulin has been frequently reported to exert beneficial effects on the host metabolism. Here, we aimed to evaluate whether dietary supplementation with inulin modulates gut microbiota structure in prediabetes, affecting glucose and lipid metabolism.

METHODS

We performed a prospective single-arm study. A total of 49 subjects with prediabetes (WHO 1999 criteria) were voluntarily enrolled. Each subject received a daily supplement with 15 g of inulin for 6 months. Glucose and lipid metabolic parameters and gut microbiota were analyzed at baseline and at 3 and 6 months after inulin intervention. Intestinal microbiota profile was evaluated using the Illumina MiSeq platform based on V3-V4 bacterial 16S rRNA gene.

RESULTS

The mean age of 49 subjects was 56.6 ± 6.9 years and BMI was 25.07 ± 3.02 kg/m². After 24 weeks of prevention, inulin significantly decreased fasting insulin (2.38 ± 0.50 vs. 2.22 ± 0.62, P=0.03) and 2-hour post-OGTT insulin (4.01 ± 0.77 vs. 3.74 ± 0.76, P=0.02) and improved HOMA-IR (1.05 ± 0.53 vs. 0.85 ± 0.66, P=0.03). Gut microbiota analysis indicated that inulin supplement resulted in an increase in the relative abundance of Actinobacteria, Bifidobacteriales, Bifidobacteriaceae, Lactobacillaceae, Bifidobacterium, Lactobacillus, and Anaerostipes both at 3 and 6 months, while with a decrease in the relative abundance of Alistipes. Spearman correlation analysis revealed altered microbial community was associated with glucose and lipids metabolic parameters.

CONCLUSIONS

Inulin supplementation improves insulin resistance of prediabetes and exerts beneficial effects on modulating the intestinal microbiota composition. These findings suggest that insulin may be a potentially novel and inexpensive intervention for prediabetes.

Detection and isolation of low molecular weight alginate- and laminaran-susceptible gut indigenous bacteria from ICR mice

Alginate and laminaran are the main water-soluble polysaccharides in edible brown algae such as arame Eisenia bicyclis. To determine the alginate- and/or laminaran-susceptible indigenous bacteria (SIB) in the gut, the caecal microbiomes of ICR mice fed a diet containing 2% low molecular weight (LMW ≒50 kDa) alginate or laminaran were analysed by 16S rRNA gene (V4) amplicon sequencing. At the phylum level abundances, compared to those in mice fed a no-fibre diet, Firmicutes was lower and Bacteroidetes was higher in both LMW alginate- or laminaran-fed mouse groups. At the operational taxonomic unit level, Bacteroides acidifaciens- and Bacteroides intestinalis-like bacteria were considered alginate- and laminaran-SIB, respectively. B. acidifaciens PS-4 isolated from the ICR mice fermented LMW alginate and laminaran and mainly produced succinate. B. intestinalis ALB-11 also isolated from these mice fermented laminaran and mainly produced lactate. These SIB might exert interactive effects with edible brown algal consumption and affect host health.

The Underlying Mechanisms of Curcumin Inhibition of Hyperglycemia and Hyperlipidemia in Rats Fed a High-Fat Diet Combined With STZ Treatment

Curcumin is the main secondary metabolite of Curcuma longa and other Curcuma spp, and has been reported to have some potential in preventing and treating some physiological disorders. This study investigated the effect of curcumin in inhibiting high-fat diet and streptozotocin (STZ)-induced hyperglycemia and hyperlipidemia in rats. Twenty-six male Sprague-Dawley (SD) rats (170–190 g) were randomly divided into a standard food pellet diet group (Control group), a high-fat diet and streptozotocin group (HF + STZ group), and a high-fat diet combined with curcumin and STZ group (HF + Cur + STZ group). Compared with the HF + STZ group, the HF + Cur + STZ group exhibited significantly reduced fasting blood glucose (FBG), total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), alanine aminotransferase (AST), and aspartate transaminase (ALT) levels, as well as liver coefficients. In the livers of these rats, the expression of malondialdehyde (MDA) and Bax was downregulated, whereas that of superoxide dismutase (SOD) and Bcl-2 was upregulated. Moreover, the liver histology of these rats was improved and resembled that of the control rats. These results suggest that curcumin prevents high-fat diet and STZ-induced hyperglycemia and hyperlipidemia, mainly via anti-oxidant and anti-apoptotic mechanisms in the liver.