Improvement in glucose tolerance and insulin sensitivity by probiotic strains of Indian gut origin in high-fat diet-fed C57BL/6J mice

Antidiabetic Effects of Pediococcus acidilactici pA1c on HFD-Induced Mice

Prediabetes (PreD), which is associated with impaired glucose tolerance and fasting blood glucose, is a potential risk factor for type 2 diabetes mellitus (T2D). Growing evidence suggests the role of the gastrointestinal microbiota in both PreD and T2D, which opens the possibility for a novel nutritional approach, based on probiotics, for improving glucose regulation and delaying disease progression of PreD to T2D. In this light, the present study aimed to assess the antidiabetic properties of Pediococcus acidilactici (pA1c) in a murine model of high-fat diet (HFD)-induced T2D. For that purpose, C57BL/6 mice were given HFD enriched with either probiotic (1 × 10¹⁰ CFU/day) or placebo for 12 weeks. We determined body weight, fasting blood glucose, glucose tolerance, HOMA-IR and HOMA-β index, C-peptide, GLP-1, leptin, and lipid profile. We also measured hepatic gene expression (G6P, PEPCK, GCK, IL-1β, and IL-6) and examined pancreatic and intestinal histology (% of GLP-1⁺ cells, % of goblet cells and villus length). We found that pA1c supplementation significantly attenuated body weight gain, mitigated glucose dysregulation by reducing fasting blood glucose levels, glucose tolerance test, leptin levels, and insulin resistance, increased C-peptide and GLP-1 levels, enhanced pancreatic function, and improved intestinal histology. These findings indicate that pA1c improved HFD-induced T2D derived insulin resistance and intestinal histology, as well as protected from body weight increase. Together, our study proposes that pA1c may be a promising new dietary management strategy to improve metabolic disorders in PreD and T2D.

Probiotics and obesity associated disease: an extended view beyond traditional strains

Interaction between intestinal microbiota and obesity is becoming abundantly according to current many scientific investigations. In this article, probiotic therapy was offered as the promising strategy of metabolic disorders control through the recovery of microbiota composition and health maintenance with the help of impact on the abovementioned mechanisms. First, this therapy is safe, with minimal side effects, well-tolerated, and appropriate for long-term use. Second, it can improve body mass, glucose, and fat metabolism, increase insulin sensitivity, and decrease systemic chronic inflammation. In conclusion, the restorative role of gut microbiota on metabolic disorders and associated diseases could open new ways in the treatment of obesity, insulin resistance, and type 2 diabetes.

Limosilactobacillus fermentum MG4295 Improves Hyperglycemia in High-Fat Diet-Induced Mice

Hyperglycemia due to uncontrolled glucose regulation is widely known as cause of diabetes, non-alcoholic fatty liver disease (NAFLD), and other complications. NAFLD refers to a condition in which fat is excessively accumulated, whether inflamed or not, and has caused serious medical problems in recent years. The aim of this study was to explore the antihyperglycemia effects of Limosilactobacillus fermentum MG4295 (L. fermentum MG4295) in high-fat diet (HFD)-induced in vivo. We demonstrated the suitability of L. fermentum MG4295 as a probiotic by observing its stability, survivability, and proliferation under simulated gastrointestinal conditions, and safety, antibiotic susceptibility, hemolysis, and enzyme activity. The potential antihyperglycemic activity of L. fermentum MG4295 was investigated in an HFD and sugar-water-induced mouse model. Administration of this strain for 12 weeks showed an improved trend in glucose tolerance, insulin, alanine amino transferase, total cholesterol, low-density lipoprotein cholesterol, and glucagon-like peptide-1. Histopathological analysis revealed that L. fermentum MG4295 significantly reduced the histopathological scores of hepatic steatosis, inflammation, and hepatocellular hypertrophy in liver tissues and lipid content in adipose tissues. Administration of L. fermentum MG4295 upregulated IRS-1, AKT, and GLUT4 and downregulated G6Pc and PEPCK expression in liver and/or muscle tissues. Our results suggest that L. fermentum MG4295 can improve hyperglycemia. Furthermore, it can be used as a dietary functional supplement to manage blood glucose.

The crosstalk between gut microbiota, intestinal immunological niche and visceral adipose tissue as a new model for the pathogenesis of metabolic and inflammatory diseases: the paradigm of type 2 diabetes mellitus

Gut microbiota (GM) comprises more than one thousand microorganisms between bacterial species, viruses, fungi, and protozoa, and represents the main actor of a wide net of molecular interactions, involving, among others, the endocrine system, immune responses, and metabolism. GM influences many endocrine functions such as adrenal steroidogenesis, thyroid function, sexual hormones, IGF-1 pathway and peptides produced in gastrointestinal system. It is fundamental in glycaemic control and obesity, while also exerting an important function in modulating the immune system and associated inflammatory disease. The result of this crosstalk in gut mucosa is the formation of the intestinal immunological niche. Visceral adipose tissue (VAT) produces about 600 different peptides, it is involved in lipid and glucose metabolism and in some immune reactions through several adipokines. GM and VAT interact in a bidirectional fashion: while gut dysbiosis can modify VAT adipokines and hormone secretion, VAT hyperplasia modifies GM composition. Acquired or genetic factors leading to gut dysbiosis or increasing VAT (i.e., Western diet) induce a proinflammatory condition, which plays a pivotal role in the development of dysmetabolic and immunologic conditions, such as diabetes mellitus. Diabetes is clearly associated with specific patterns of GM alterations, with an abundance or reduction of GM species involved in controlling mucosal barrier status, glycaemic levels and exerting a pro- or anti-inflammatory activity. All these factors could explain the higher incidence of several inflammatory conditions in Western countries; furthermore, besides the specific alterations observed in diabetes, this paradigm could represent a common pathway acting in many metabolic conditions and could pave the way to a new, interesting therapeutic approach.

Treatment with broad-spectrum antibiotics upregulates Sglt1 and induces small intestinal villous hyperplasia in mice

Although extensive evidence indicates that the gut microbiota plays a crucial role in regulating glucose homeostasis, the exact regulatory mechanism remains unclear. This study aimed to investigate the effect of broad-spectrum antibiotics on the expression of glucose transporters, histomorphology of the small intestine, and glucose metabolism in mice. C57BL/6 mice were administered drinking water with or without a broad-spectrum antibiotic combination for 4 weeks. Thereafter, an oral glucose tolerance test was performed. Body weight, small intestine histopathology, mRNA levels of glucose transporters (SGLT1 and GLUT2) and intestinal transcription factors (CDX1 and CDX2) were evaluated. SGLT1 and CDX1 were upregulated in the small intestine upon antibiotic administration compared with that in the control group. The height and surface area of the jejunal villi were significantly higher upon antibiotic administration than in the control group. Fasting glucose levels were significantly higher upon antibiotic administration than in the control group. The present results indicate that treatment with broad-spectrum antibiotics upregulates SGLT1 and CDX1 and induces hyperplasia in the small intestine, thus increasing fasting blood glucose levels. Our results further the current understanding of the effects of broad-spectrum antibiotics on the gut microbiota and glucose homeostasis that may have future clinical implications.

Inhibitory Effect and Potential Mechanism of Lactobacillus plantarum YE4 against Dipeptidyl Peptidase-4

This study investigated the inhibitory effect and mechanism of 12 LAB strains isolated from Chinese fermented foods on dipeptidyl peptidase-4 (DPP-4) using the Caco-2 cell model. The results showed that the inhibitory effect of cell-free extracts (CFEs) collected from each LAB strain on DPP-4 was higher than that of the cell-free excretory supernatants. The CFEs from Lactobacillus plantarum YE4 (YE4-CFE) exhibited the strongest DPP-4 inhibitory activity (24.33% inhibition). Furthermore, YE4-CFE altered the TNF and MAPK signaling pathways. Additionally, the YE4-CFE ultrafiltration fraction (<3 kDa) displayed a similar DPP-4 inhibitory activity to YE4-CFE. UHPLC-MS/MS identified 19 compounds with a relative proportion of more than 1% in the <3 kDa fraction, and adenine, acetylcholine, and L-phenylalanine were the top three substances in terms of proportion. Altogether, the inhibitory effect of YE4-CFE on DPP-4 was associated with the TNF and MAPK signaling pathways, and with the high proportion of adenine, acetylcholine, and L-phenylalanine.

Bacillus toyonensis SAU-19 Ameliorates Hepatic Insulin Resistance in High-Fat Diet/Streptozocin-Induced Diabetic Mice

Insulin resistance (IR) is a hallmark of type 2 diabetes mellitus (T2DM). This study was performed to investigate the antidiabetic effect of Bacillus toyonensis SAU-19 and its possible mechanisms of action in mice with type 2 diabetes mellitus (T2DM). Thirty SPFKM mice were randomly assigned to three groups: control, diabetic model, and diabetes + Bacillus toyonensis SAU-19 group. After 35 days, blood was collected for biochemical analysis and liver tissue samples for histopathological analysis using H&E staining, qPCR, and ELISA. The results showed that the administration of B. toyonensis SAU-19 significantly improved the blood glucose, hepatic insulin resistance, and morphological changes of the liver characterized by significant improvement of dyslipidemia, glycogen synthesis, and antioxidant status (p < 0.05), indicating the strains’ ameliorating effects on hepatic insulin resistance in T2DM. In conclusion, the probiotic strain (B. toyonensis SAU-19) inhibits T2DM by reducing insulin resistance, improving antioxidant status, and downregulating genes related to glucose synthesis; hence, it may be used in treating diabetes and other metabolic disorders. This study provides the basis for further studies into the molecular mechanisms of B. toyonensis SAU-19 in treating T2DM.

Different Types and Functional Effects of Probiotics on Human Health through Regulating Glucose Homeostasis

With the increasing improvement of people's living standards, hyperglycemia has become one of the most frequent diseases in the world. The current drug therapy may have some negative effects and even cause some complications. As one of the most popular functional ingredients, probiotic bacteria have been proven to play important roles in balancing the glucose homeostasis level in animal and human clinic trials. In this perspective, we sorted three types of probiotics, discussed probiotic safety evaluation, and listed the known probiotic functional foods that assist to control glucose homeostasis. Then, the further summarization of the mechanisms on how probiotic bacteria could regulate glucose homeostasis and the developing trend of probiotic functional foods were discussed.

Probiotics and synbiotics show clinical efficacy in treating gestational diabetes mellitus: A meta-analysis

BACKGROUND

This study performed a systematic and meta-analysis of randomized controlled trials (RCTs) to explore the efficacy of probiotic- and symbiotic-based supplements in the treatment of gestational diabetes mellitus (GDM).

METHODS

We performed a meta-analysis to evaluate the efficacy of probiotics/synbiotics in GDM treatment, following a systematic search in Web of Science, PubMed, Cochrane Library, and EBSCO databases for articles published up to July 2020.

RESULTS

In total, 12 RCTs comprising 894 participants, were analyzed. Compared to the placebo, patients administered with probiotic and synbiotic supplements benefited more with regards to glucose and lipid metabolism as well as anti-inflammation and antioxidant capacity including insulin of change (WMD: 3.57, 95%CI: -5.26, -1.88), very-low-density lipoprotein (VLDL) (WMD: -5.03, 95%CI: -8.26, -1.79), nitric oxide (NO) at the end of trial (WMD: 2.31, 95%CI: 0.91, 3.70), total antioxidant capacity (TAC) at the end of trial (SMD: 0.74, 95%CI: 0.21, 1.27), high-sensitivity C-reactive protein (hsCRP) at the end of trial (SMD: -1.23, 95%CI: -1.97, -0.49). Besides, probiotic and synbiotic supplements improved outcomes on fetal hyperbilirubinemia risk (RR: 0.26, 95%CI: 0.12, 0.55), fetal macrosomia risk (RR: 0.47, 95%CI: 0.27, 0.83) and newborn weight (SMD: -0.29, 95%CI: -0.50, -0.09).

CONCLUSIONS

Findings from this work demonstrate that probiotic/symbiotic-based interventions improve glucose and lipid metabolism, anti-inflammatory and antioxidant ability in diet-controlled GDM patients, and exert beneficial outcomes on fetal hyperbilirubinemia, fetal macrosomia, and newborn weight.

Gut-Microbial Metabolites, Probiotics and Their Roles in Type 2 Diabetes

Type 2 diabetes (T2D) is a worldwide prevalent metabolic disorder defined by high blood glucose levels due to insulin resistance (IR) and impaired insulin secretion. Understanding the mechanism of insulin action is of great importance to the continuing development of novel therapeutic strategies for the treatment of T2D. Disturbances of gut microbiota have been widely found in T2D patients and contribute to the development of IR. In the present article, we reviewed the pathological role of gut microbial metabolites including gaseous products, branched-chain amino acids (BCAAs) products, aromatic amino acids (AAAs) products, bile acids (BA) products, choline products and bacterial toxins in regulating insulin sensitivity in T2D. Following that, we summarized probiotics-based therapeutic strategy for the treatment of T2D with a focus on modulating gut microbiota in both animal and human studies. These results indicate that gut-microbial metabolites are involved in the pathogenesis of T2D and supplementation of probiotics could be beneficial to alleviate IR in T2D via modulation of gut microbiota.

A high potency multi-strain probiotic improves glycemic control in children with new-onset type 1 diabetes mellitus: A randomized, double-blind, and placebo-controlled pilot study

BACKGROUND

Studies in animal models and humans with type 1 diabetes mellitus (T1DM) have shown that probiotic supplementation leads to decreased pro-inflammatory cytokines (responsible for damaging β-cells of the pancreas), improved gut barrier function, and induction of immune tolerance.

OBJECTIVE

To study the effect of supplementation of probiotics in children with T1DM on glycemic control, insulin dose, and plasma C-peptide levels.

METHODS

A single-centered, double-blinded, and randomized placebo-controlled pilot trial was conducted in children (2-12 years) with new-onset T1DM. Ninety-six children were randomized and allocated to Placebo or Intervention groups. The intervention included high dose (112.5 billion viable lyophilized bacteria per capsule) multi-strain probiotic De Simone formulation (manufactured by Danisco-Dupont) sold as Visbiome® in India. The probiotic was supplemented for 3 months and HbA1c, fasting C-peptide, blood sugar records, and insulin dose was recorded at baseline and 3 months.

RESULTS

A total of 90 patients (45 in each group) were analyzed for outcome parameters. We found a significant decrease in HbA1c (5.1 vs. 3.8; p = 0.021) and a significant decline in total and bolus insulin dose (U/kg/day; p = 0.037 and 0.018, respectively) in the intervention group when compared with the placebo group. A significantly higher (p = 0.023) number of children achieved remission in the treatment group. We did not notice adverse effects in either of the study groups.

CONCLUSION

Children with newly diagnosed T1DM managed with standard treatment along with probiotics showed better glycemic control and a decrease in insulin requirements; however, more extensive studies are further warranted.

Interaction between intestinal microbiota and tumour immunity in the tumour microenvironment

In recent years, an increasing number of studies have reported that intestinal microbiota have an important effect on tumour immunity by affecting the tumour microenvironment (TME). The intestinal microbiota are closely associated with various immune cells, such as T lymphocytes, natural killer cells (NK cells) and macrophages. Some bacteria, such as Akkermansia muciniphila (A. muciniphila) and Lactobacillus reuteri (L. reuteri), have been shown to improve the effect of tumour immunity. Furthermore, microbial imbalance, such as the increased abundance of Fusobacterium nucleatum (F. nucleatum) and Helicobacter hepaticus (H. hepaticus), generally causes tumour formation and progression. In addition, some microbiota also play important roles in tumour immunotherapy, especially PD-L1-related therapies. Therefore, what is the relationship between these processes and how do they affect each other? In this review, we summarize the interactions and corresponding mechanisms among the intestinal microbiota, immune system and TME to facilitate the research and development of new targeted drugs and provide new approaches to tumour therapy.

Synbiotic (Lactiplantibacillus pentosus GSSK2 and isomalto-oligosaccharides) supplementation modulates pathophysiology and gut dysbiosis in experimental metabolic syndrome

Metabolic syndrome a lifestyle disease, where diet and gut microbiota play a prodigious role in its initiation and progression. Prophylactic bio-interventions employing probiotics and prebiotics offer an alternate nutritional approach towards attenuating its progression. The present study aimed to evaluate the protective efficacy of a novel synbiotic (Lactiplantibacillus pentosus GSSK2 + isomalto-oligosaccharides) in comparison to orlistat in an experimental model of metabolic syndrome. It was observed that supplementation of synbiotic for 12 weeks to Sprague Dawley rats fed with high fat diet (HFD), ameliorated the morphometric parameters i.e. weight gain, abdominal circumference, Lee's index, BMI and visceral fat deposition along with significantly increased fecal Bacteroidetes to Firmicutes ratio, elevated population of Lactobacillus spp., Akkermansia spp., Faecalibacterium spp., Roseburia spp. and decreased Enterobacteriaceae compared with HFD animals. Additionally, synbiotic administration to HFD animals exhibited improved glucose clearance, lipid biomarkers, alleviated oxidative stress, prevented leaky gut phenotype, reduced serum lipopolysaccharides and modulated the inflammatory, lipid and glucose metabolism genes along with restored histomorphology of adipose tissue, colon and liver compared with HFD animals. Taken together, the study highlights the protective potential of synbiotic in comparison with its individual components in ameliorating HFD-induced metabolic complications.

The characteristics of intestinal flora in overweight pregnant women and the correlation with gestational diabetes mellitus

OBJECTIVE

To investigate the characteristics of intestinal flora in overweight pregnant women and the correlation with gestational diabetes mellitus (GDM).

METHODS

A total of 122 women were enrolled and divided into four groups according to their pre-pregnancy BMI and the presence of GDM: group 1 (n = 71) with a BMI <24 kg/m2, without GDM; group 2 (n = 27) with a BMI <24 kg/m2, with GDM; group 3 (n = 17) with a BMI ≥24 kg/m2, without GDM; and group 4 (n = 7) with a BMI ≥24 kg/m2 with GDM. Feces were collected on the day that the oral glucose tolerance test was conducted. The V3-V4 variable region of 16S rRNA was sequenced using the Illumina Hiseq 2500 platform, and a bioinformatics analysis was conducted.

RESULTS

There were differences between the four groups in the composition of intestinal flora, and it was significantly different in group 4 than in the other three groups. Firmicutes accounted for 36.4% of the intestinal flora in this group, the lowest among the four groups, while Bacteroidetes accounted for 50.1%, the highest among the four groups, making ratio of these two bacteria approximately 3:5, while in the other three groups, this ratio was reversed. In women with a BMI <24 kg/m2, the insulin resistance index (homeostatic model assessment for insulin resistance (HOMA-IR)) in pregnant women with GDM was higher than in those without (P3 = 0.026).

CONCLUSION

The composition of the intestinal flora of pregnant women who were overweight or obese before pregnancy and suffered from GDM was significantly different than women who were not overweight or did not suffer from GDM.

Regulatory mechanisms of energy metabolism and inflammation in oleic acid-treated HepG2 cells from Lactobacillus acidophilus NX2-6 extract

In this study, the cell-free extracts (CFE) of Lactobacillus acidophilus NX2-6 were utilized to treat oleic acid (OA)-induced hepatic steatosis. It was found that CFE treatment improved lipid metabolism in OA-induced hepatic steatosis model by downregulating several lipogenic genes but increasing expression levels of lipolysis-related genes. In addition, gene expression analysis revealed that CFE treatment promoted mitochondrial biogenesis and fission by upregulating the mRNA levels of PGC-1α, PGC-1β, Sirt1, NRF1, and Fis1. CFE treatment also increased protein expression of p-AMPKα, PGC-1α, ACOX1, and Sirt1 in OA-treated cells, suggesting that CFE possessed ability to improve energy metabolism. Furthermore, CFE treatment also reversed OA-induced oxidative stress by increasing CAT activity and protein level of Nrf-2 as well as reducing protein expression of ATF6, XBP1, GRP78, p50, and p-ERK, indicating that CFE could inhibit endoplasmic reticulum stress and sterile inflammation. Thus, L. acidophilus NX2-6 had potential to fight against NAFLD. PRACTICAL APPLICATIONS: Diet-induced hepatic steatosis is one of major public health concerns all over the world. Hepatic steatosis is accompanied by disregulation of lipid metabolism and energy metabolism, endoplasmic reticulum stress, oxidative stress as well as chronic inflammation. It is reported that probiotics are considered as emerging therapeutic strategy to alleviate hepatic steatosis. This study indicated potential applications of dead probiotics in the prevention of hepatic steatosis and development of functional foods.

Chocolate as Carrier to Deliver Bioactive Ingredients: Current Advances and Future Perspectives

Consumer demand for healthier foods with improved taste and convenience has urged the food industry to develop functional foods added with bioactive ingredients that can supplement basic nutrition (food supplement) or exert a pharmacological effect (nutraceuticals). Chocolate could be used as an ideal carrier to deliver bioactive ingredients, mainly due to its high acceptability by consumers. However, a drawback of using chocolate as functional food is its high sugar content, which impedes its commercialization with the diabetic population. Therefore, there is need to develop sugar-free chocolate formulations added with bioactive ingredients. Nevertheless, sugar replacement and bioactive ingredients addition is a major technological challenge that affects texture, rheology, and sensory properties of chocolate. This review is designed as a practical guide for researchers and food industries to develop the next generation of functional chocolates. Different functional chocolate formulations, including sugar-free, are reviewed as potential carriers for the delivery of bioactive compounds. The physicochemical properties and sensory acceptability of the functional chocolates presented are also highlighted. Finally, future perspectives, such as the use of nanotechnology to improve the bioaccessibility and bioavailability of active ingredients, as well as the need for clinical trials to validate the pharmacological effect of functional chocolates, are also discussed.

Oral Administration of Lactobacillus casei and Bifidobacterium bifidum Improves Glucagon like Peptide-1(GLP-1) and Glucose-Dependent Insulinotropic Polypeptide (GIP) Level in Streptozotocin Induced Diabetic Rats

The gut microbiome plays significant role in the function and integrity of the gastrointestinal tract. They also maintain immune homeostasis and host energy metabolism. The metabolic products of these intestinal microbes can alter carbohydrate metabolism, nutrient absorption and reduce appetite to promote healthy lifestyle. Intestinal disbiosis observed in metabolic disorders like obesity and diabetes. Restoration of dysbiosed gut microbiome through oral administration of probiotics that may have profound health effect in diabetes. In case of diabetes, reports postulated impaired level of incretin, therefore we explored the effect of oral administration of probiotic bacteria Lactobacillus casei NCDC 017 (LC017) and Bifidobacterium bifidum NCDC 231 (BB231) alone and in combination on secretion of incretin hormones such as glucagon like peptide-1 and glucose dependent insulinotropic polypeptide. Thirty six male Wistar rats were randomly divided into six groups and diabetes was induced by single dose of streptozotocin (50 mg/kg body weight) in experimental rats intraperitonially except a group of healthy rats. The diabetic rats were daily administered orally with single dose (~107cfu/ml) of LC017 and BB231 alone and in combination for 28 days. Also, one group of diabetic rats was treated with an anti-diabetic drug, acarbose (10mg/kg body weight) and used a standard control. The change in body weight, sucrose tolerance test, GLP-1, GIP level in serum and GLP-1 level in different part of intestine were observed. The results have shown reduction in body weight in diabetic rats as compared to non-diabetic rats but improved after treatment of probiotic bacteria. Administration of LC017 and BB231 significantly improved GLP-1 and GIP level which were initially impaired in diabetic rats and their combination significantly decreased glucose level in sucrose tolerance test. This study indicated that LC017 and BB231 have significant hypoglycaemic potential in diabetic rats by increasing GLP-1 and GIP level. These findings offered a base for the use of LC017 and BB231 for improvement and treatment of diabetes.

Gut microbiota influence in type 2 diabetes mellitus (T2DM)

A strong and expanding evidence base supports the influence of gut microbiota in human metabolism. Altered glucose homeostasis is associated with altered gut microbiota, and is clearly associated with the development of type 2 diabetes mellitus (T2DM) and associated complications. Understanding the causal association between gut microbiota and metabolic risk has the potential role of identifying susceptible individuals to allow early targeted intervention.

Combination of Limosilactobacillus fermentum MG4231 and MG4244 attenuates lipid accumulation in high-fat diet-fed obese mice

We investigated the anti-obesity effect and the underlying mechanisms of action of human-derived Limosilactobacillus fermentum MG4231, MG4244, and their combination, in high-fat diet-induced obese mice. Administration of the Limosilactobacillus strains decreased body weight gain, liver and adipose tissue weight, and glucose tolerance. Serum levels of total cholesterol, low-density lipoprotein-cholesterol, and leptin were reduced, while adiponectin increased. The administration of Limosilactobacillus strains improved the histopathological features of liver tissue, such as hepatic atrophy and inflammatory penetration, and significantly reduced the content of triglyceride in the liver. Limosilactobacillus administration discovered a significant reduction in the size of the adipocytes in the epididymal tissue. Limosilactobacillus treatment significantly reduced the expression of important regulators in lipid metabolism, including peroxisome proliferator-activated receptor γ, CCAAT/enhancer-binding protein α, fatty acid synthase (FAS), adipocyte-protein 2, and lipoprotein lipase in the epididymal tissue. Also, Limosilactobacillus lowered sterol regulatory element-binding protein 1-c and FAS in the liver tissue. Such changes in the expression of these regulators in both liver and epididymis tissue were caused by Limosilactobacillus upregulating phosphorylation of AMP-activated protein kinase and acetyl-CoA carboxylase. Therefore, we suggest that the use of the combination of L. fermentum MG4231 and MG4244, as probiotics could effectively inhibit adipogenesis and lipogenesis from preventing obesity.

Roux-en-Y gastric bypass potentially improved intestinal permeability by regulating gut innate immunity in diet-induced obese mice

Roux-en-Y gastric bypass (RYGB) has been demonstrated to be the most effective treatment for morbid obesity, yet the impact of RYGB on intestinal permeability is not fully known. In this work, we subjected obese mice to RYGB and sham operation procedures. Serum lipopolysaccharide (LPS) level, inflammatory cytokines and intestinal permeability were measured at 8 weeks post surgery. In contrast to sham surgery, RYGB reduced body weight, improved glucose tolerance and insulin resistance, and decreased serum levels of LPS, IL6 and TNFα. Intestinal permeability of the common limb and colon was significantly improved in the RYGB group compared to the sham group. The mRNA levels of IL1β, IL6, and TLR4 in the intestine were significantly decreased in the RYGB group compared with the sham group. The expression levels of intestinal islet-derived 3β (REG3β), islet-derived 3γ (REG3γ) and intestinal alkaline phosphatase (IAP) were higher in the RYGB group than in the sham group. In conclusion, in a diet-induced obesity (DIO) mouse model, both decreased intestinal permeability and attenuated systemic inflammation after RYGB surgery were associated with improved innate immunity, which might result from enhanced production of IAP and antimicrobial peptides.

Recent Progress in Metabolic Syndrome Research and Therapeutics

Metabolic syndrome (MetS) is a well-defined yet difficult-to-manage disease entity. Both the precipitous rise in its incidence due to contemporary lifestyles and the growing heterogeneity among affected populations present unprecedented challenges. Moreover, the predisposed risk for developing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in populations with MetS, and the viral impacts on host metabolic parameters, underscores the need to investigate this mechanism thoroughly. Recent investigations of metabolomics and proteomics have revealed not only differentially expressed substances in MetS, but also the consequences of diet consumption and physical activity on energy metabolism. These variations in metabolites, as well as protein products, also influence a wide spectrum of host characteristics, from cellular behavior to phenotype. Research on the dysregulation of gut microbiota and the resultant inflammatory status has also contributed to our understanding of the underlying pathogenic mechanisms. As for state-of-the-art therapies, advancing depictions of the bio-molecular landscape of MetS have emerged and now play a key role in individualized precision medicine. Fecal microbiota transplantation, aiming to restore the host's homeostasis, and targeting of the bile acid signaling pathway are two approaches to combatting MetS. Comprehensive molecular inquiries about MetS by omics measures are mandatory to facilitate the development of novel therapeutic modalities.

Protective and ameliorating effects of probiotics against diet-induced obesity: A review

Diet-induced obesity is one of the major public health concerns all over the world, and obesity also contributes to the development of other chronic diseases such as non-alcoholic fatty acid liver disease, type 2 diabetes mellitus and cardiovascular diseases. Evidence shows that the pathogenesis of obesity and obesity-associated chronic diseases are closely related to dysregulation of lipid metabolism, glucose metabolism and cholesterol metabolism, and oxidative stress, endoplasmic reticulum stress, abnormal gut microbiome and chronic low-grade inflammation. Recently, in view of potential effects on lipid metabolism, glucose metabolism, cholesterol metabolism and intestinal microbiome, as well as anti-oxidative and anti-inflammatory activities, natural probiotics, including live and dead probiotics, and probiotic components and metabolites, have attracted increasing attention and are considered as novel strategies for preventing and ameliorating obesity and obesity-related chronic diseases. Specifically, this review is presented on the anti-obesity effects of probiotics and underlying molecular mechanisms, which will provide a theoretical basis of anti-obesity probiotics for the development of functional foods.

Lactiplantibacillus plantarum MG4296 and Lacticaseibacillus paracasei MG5012 Ameliorates Insulin Resistance in Palmitic Acid-Induced HepG2 Cells and High Fat Diet-Induced Mice

The purpose of this study was to evaluate the capacity of Lactiplantibacillus plantarum MG4296 (MG4296) and Lacticaseibacillus paracasei MG5012 (MG5012) on insulin resistance (IR) and diabetes-related metabolic changes in palmitic acid (PA)-induced HepG2 cells and high-fat diet-induced mice. In vitro, cell-free extracts of MG4296 and MG5012 alleviated IR by increasing glucose uptake and glycogen content in PA-induced insulin-resistant HepG2 cells. In vivo, MG4296 and MG5012 supplementation markedly decreased body weight and glucose tolerance. Administration of both strains also improved serum glucose, glycated hemoglobin, insulin, triglyceride, LDL/HDL ratio, and homeostatic model assessment of IR (HOMA-IR). Histopathological analysis of liver tissue demonstrated a significant reduction in lipid accumulation and glycogen content. Moreover, MG4296 and MG5012 treatment enhanced phosphoinositide-3 kinase (PI3K)/protein kinase B (Akt) expression in the liver. Overall, MG4296 and MG5012 could prevent HFD-induced glucose tolerance and hyperglycemia by improving IR. Therefore, L. plantarum MG4296 and L. paracasei MG5012 could be useful as new probiotics candidates to improve T2DM.

Association of diabetes and microbiota: An update

Diabetes is an emerging health condition globally and is suggested to have a direct connection with the gut microbiota that determine our metabolic outcomes. Sensitivity to insulin and glucose metabolism is normal in healthy people as compared to those people who cannot maintain their glucose metabolism. One of the reasons of the differences is that healthy people have different microbiome that leads to achieve more short chain fatty acids and make up more branched amino acids, while the gut microbiota of the other group of people are more likely to produce compounds that affects glucose metabolism. Herein, this review will present the research related to the impact of gut microbes on diabetes carried out in the past decade. The review focus on the relation between gut microbiota and Type-1 Diabetes (T1D), Type-2 Diabetes (T2D), and how gut microbiota could be an alternative therapy for treatment of diabetes.

The Relationship between the Gut Microbiome and Metformin as a Key for Treating Type 2 Diabetes Mellitus

Metformin is the first-line pharmacotherapy for treating type 2 diabetes mellitus (T2DM); however, its mechanism of modulating glucose metabolism is elusive. Recent advances have identified the gut as a potential target of metformin. As patients with metabolic disorders exhibit dysbiosis, the gut microbiome has garnered interest as a potential target for metabolic disease. Henceforth, studies have focused on unraveling the relationship of metabolic disorders with the human gut microbiome. According to various metagenome studies, gut dysbiosis is evident in T2DM patients. Besides this, alterations in the gut microbiome were also observed in the metformin-treated T2DM patients compared to the non-treated T2DM patients. Thus, several studies on rodents have suggested potential mechanisms interacting with the gut microbiome, including regulation of glucose metabolism, an increase in short-chain fatty acids, strengthening intestinal permeability against lipopolysaccharides, modulating the immune response, and interaction with bile acids. Furthermore, human studies have demonstrated evidence substantiating the hypotheses based on rodent studies. This review discusses the current knowledge of how metformin modulates T2DM with respect to the gut microbiome and discusses the prospect of harnessing this mechanism in treating T2DM.

Recognizing the Benefits of Pre-/Probiotics in Metabolic Syndrome and Type 2 Diabetes Mellitus Considering the Influence of Akkermansia muciniphila as a Key Gut Bacterium

Metabolic syndrome (MetS) and type 2 diabetes mellitus (T2DM) are diseases that can be influenced by the structure of gut microbiota, whose improvement is often neglected in metabolic pathology. This review highlights the following main aspects: the relationship between probiotics/gut microbes with the pathogenesis of MetS, the particular positive roles of Akkermansia muciniphila supplementation in the onset of MetS, and the interaction between dietary polyphenols (prebiotics) with gut microbiota. Therefore, an extensive and in-depth analysis of the often-neglected correlation between gut microbiota and chronic metabolic diseases was conducted, considering that this topic continues to fascinate and stimulate researchers through the discovery of novel strains and their beneficial properties.

Qingke β-glucan synergizes with a β-glucan-utilizing Lactobacillus strain to relieve capsaicin-induced gastrointestinal injury in mice

Capsaicin (CAP) is the main pungent component in capsicum fruits. Eating too much CAP leads to gastrointestinal injury. Previously, Qingke β-glucan combined with β-glucan-utilizing Lactobacillus plantarum S58 (LP.S58) ameliorated high fat-diet-induced obesity, but their effects on CAP-induced gastrointestinal injury have not been investigated. Our results showed that Qingke β-glucan reduced the CAP-induced gastrointestinal injury in Kunming mice. The serum levels of inflammatory cytokines and gastrointestinal hormones, and the localized inflammation and the expression of EGF, EGFR, VEGF, and ZO-1 in the gastrointestinal tissues in CAP-treated mice were partly restored by Qingke β-glucan. The CAP-induced increase in the abundances of proinflammatory intestinal bacteria was also reduced by Qingke β-glucan. More importantly, we found that these beneficial effects of Qingke β-glucan were markedly enhanced by β-glucan-utilizing LP.S58 supplementation. Our study indicated that Qingke β-glucan coupled with β-glucan-utilizing LP.S58 relieved CAP-induced gastrointestinal injury.

Influence of the Intestinal Microbiota on Diabetes Management

In recent decades, there has been a very rapid increase in the prevalence of diabetes globally, with serious health and economic implications. Although today there are several therapeutic treatments for this disease, these do not address the causes of the disease and have serious side effects, so it is necessary to seek new treatments to replace or complement the existing ones. Among these complementary treatments, a strong link between the intestinal microbiota and diabetes has been demonstrated, which has focused attention on the use of biotherapy to regulate the function of the intestinal microbiota and, thus, treat diabetes. In this way, the main objective of this work is to provide a review of the latest scientific evidence on diabetes, gathering information about new trends in its management, and especially, the influence of the intestinal microbiota and microbiome on this pathology. It is possible to conclude that the relationship between the intestinal microbiota and diabetes is carried out through alterations in energy metabolism, the immune system, changes in intestinal permeability, and a state of low-intensity systemic inflammation. Although, currently, most of the experimental work, using probiotics for diabetes management, has been done on experimental animals, the results obtained are promising. Thus, the modification of the microbiota through biotherapy has shown to improve the symptoms and severity of diabetes through various mechanisms related to these alterations.

Effect of probiotics on oxidative stress and inflammatory status in diabetic nephropathy: A systematic review and meta-analysis of clinical trials

This systematic review and meta-analysis was performed to evaluate the effect of probiotics on serum high sensitivity-C reactive protein (hs-CRP) and oxidative stress biomarkers among patients with Diabetic Nephropathy (DN). Electronic databases were searched through May 10, 2020. Seven trials that included 340 patients were identified for analysis. Meta-analysis indicated that probiotics significantly reduced hs-CRP (WMD = -1.53 mg/L; 95% CI = -2.38, -0.69; P < 0.001) and Malondialdehyde (MDA) (WMD = -0.62 ɥmol/L; 95% CI = -1.18, -0.06; P = 0.030) levels in DN patients, whereas they increased Glutathione (GSH) (WMD = 73.84 ɥmol/L; 95% CI = 24.3, 123.29; P = 0.003) and Total Antioxidant Capacity (TAC) (WMD = 26.54 mmol/L; 95% CI = 6.23, 46.85; P = 0.010). Therefore, probiotics may improve hs-CRP and oxidative stress biomarkers in DN population.

Intestinal microflora in metabolic diseases

Metabolic diseases are a class of diseases caused by abnormal metabolism of glucose, protein, and lipids in the body. Accumulating evidence supports the important relevance of intestinal dysbacteriosis to metabolic diseases. Specifically, intestinal dysbacteriosis may disrupt intestinal barrier function, thereby inducing endotoxemia, bile acid metabolism disorders, and systemic chronic low-grade inflammation, which promote metabolic disease progression and complications. With the progression of the disease, the change in intestinal environment and the influence of drugs and diet in turn aggravate the imbalance of intestinal flora, which eventually leads to poor prognosis. This highlights the potential for developing therapies to prevent and treat metabolic diseases by changing the intestinal bacterial structure. Probiotics, prebiotics, synbiotic therapy, fecal bacteria transplantation, and traditional Chinese medicine can be used to treat metabolic diseases by maintaining the balance of intestinal bacteria and counteracting harmful bacterial products. This article reviews the changes of intestinal bacteria in metabolic diseases, the possible mechanism of intestinal bacteria affecting metabolic diseases, and the application of intestinal bacteria in the treatment of metabolic diseases, with an aim to provide a reference for the diagnosis and prevention of metabolic diseases by targeting intestinal flora.

Herbal formula LLKL ameliorates hyperglycaemia, modulates the gut microbiota and regulates the gut-liver axis in Zucker diabetic fatty rats

LLKL, a new traditional Chinese medicine formula containing Edgeworthia gardneri (Wall.) Meisn., Sibiraea angustata and Crocus sativus L. (saffron), was designed to ameliorate type 2 diabetes mellitus. Despite the therapeutic benefits of LLKL, its underlying mechanisms remain elusive. This study evaluated the LLKL anti-diabetic efficacy and its effect on gut microbiota to elucidate its mechanism of action in Zucker diabetic fatty rats. We found that administration of different LLKL concentrations (4.68, 2.34 and 1.17 g/kg/d) improved several diabetic parameters after a 6-week treatment. Moreover, LLKL modulated gut microbiota dysbiosis, increased the expression of occluding and maintained intestinal epithelial homeostasis, leading to a reduction in LPS, TNF-α and IL-6 levels. Hepatic transcriptomic analysis showed that the Toll-like receptor signalling pathway was markedly enriched by LLKL treatment. RT-qPCR results validated that LLKL treatment decreased the expressions of TLR4, MyD88 and CTSK. Furthermore, a gene set enrichment analysis indicated that LLKL enhanced the insulin signalling pathway and inhibited glycerolipid metabolism and fatty acid metabolism, which were verified by the liver biochemical analysis. These findings demonstrate that LLKL ameliorates hyperglycaemia, modulates the gut microbiota and regulates the gut-liver axis, which might contribute to its anti-diabetic effect.

Probiotics supplementation and insulin resistance: a systematic review

BACKGROUND

Research on intestinal microbiota has grown considerably, as well as the interest on probiotics' supplementation effects on metabolism. Considering high prevalence rates of metabolic diseases linked by insulin resistance, we performed a systematic review of existing literature which addressed the role of probiotics in modulating insulin sensitivity in animals and humans.

METHODS

This systematic review was based on PRISMA guidelines. Searches for original articles published in English from 1990 to January 2020 were made in the electronic database of PubMed from the National Library of Medicine, using Medical Subject Headings to identify longitudinal studies conducted in animals and humans which reported effects of probiotics in a variety of insulin resistance parameters.

RESULTS

Overall, results from 27 probiotic interventions (Lactobacillus, Bifidobacterium, Clostridium and Akkermansia) indicated significant beneficial changes in insulin resistance measures in animal studies. Additionally, they improved lipid profile, inflammatory and oxidative markers, short-chain fatty acids production and microbiota composition. In seven clinical trials, samples and designs were heterogeneous. Five showed benefits in insulin resistance parameters and in two others no effect was detected.

CONCLUSION

Available data regarding the effects of certain probiotics do not guarantee sustained amelioration of insulin resistance in humans. Consistent beneficial results for intestinal barrier function, immune system and metabolism were reported in animals may encourage long-term randomized clinical trials in people with obesity and cardiometabolic risk. Whether supplementation with probiotics in combination with medications and/or prebiotics, associated with a healthy lifestyle, will prove useful to attenuate insulin resistance requires further investigation.

Engineered probiotic and prebiotic nutraceutical supplementations in combating non-communicable disorders: A review

Nutritional supplementations are a form of nutrition sources that may help in improving health complexities throughout the life span of a person. Under the umbrella of food supplementations, nutraceuticals are products extracted from edible sources that provide medical benefits along with primary nutritional value, these can be considered as functional foods. These nutraceutical supplementations are also evidenced in altering the commensal gut microbiota and help to prevent or fight against chronic non-communicable degenerative diseases in adults including neurological disorders (Autism Spectrum Disorder [ASD], Parkinson's disease [PD] and Multiple sclerosis [MS]) and metabolic disorder (Type-II Diabetes, Obesity and non-alcoholic fatty liver disease). Even the complexities of preterm babies like extra-uterine growth restriction, necrotizing enterocolitis, infant eczema and allergy (during pregnancy) and bronchopulmonary dysplasia, etc. could also be lessened up by providing proper nutrition. Molecular perceptive of inflammatory and apoptotic modulators regulating the pathogenesis of these health risks, their control and management by probiotics and prebiotics could further emphasize the scientific overview of their utility. The pivotal role of nutraceutical supplementations in regulating or modulating molecular pathways coupled with the above mentioned non-communicable diseases are briefly described. Lastly, an overall introduction to the sophisticated genome-editing techniques and advanced delivery systems in therapeutic activities applicable under these health risks are also emphasized in this paper.

An Overview of Gut Microbiota and Colon Diseases with a Focus on Adenomatous Colon Polyps

It is known and accepted that the gut microbiota composition of an organism has an impact on its health. Many studies deal with this topic, the majority discussing gastrointestinal health. Adenomatous colon polyps have a high prevalence as colon cancer precursors, but in many cases, they are hard to diagnose in their early stages. Gut microbiota composition correlated with the presence of adenomatous colon polyps may be a noninvasive and efficient tool for diagnosis with a high impact on human wellbeing and favorable health care costs. This review is meant to analyze the gut microbiota correlated with the presence of adenomatous colon polyps as the first step for early diagnosis, prophylaxis, and treatment.

Microbiota and Diabetes Mellitus: Role of Lipid Mediators

Diabetes Mellitus (DM) is an inflammatory clinical entity with different mechanisms involved in its physiopathology. Among these, the dysfunction of the gut microbiota stands out. Currently, it is understood that lipid products derived from the gut microbiota are capable of interacting with cells from the immune system and have an immunomodulatory effect. In the presence of dysbiosis, the concentration of lipopolysaccharides (LPS) increases, favoring damage to the intestinal barrier. Furthermore, a pro-inflammatory environment prevails, and a state of insulin resistance and hyperglycemia is present. Conversely, during eubiosis, the production of short-chain fatty acids (SCFA) is fundamental for the maintenance of the integrity of the intestinal barrier as well as for immunogenic tolerance and appetite/satiety perception, leading to a protective effect. Additionally, it has been demonstrated that alterations or dysregulation of the gut microbiota can be reversed by modifying the eating habits of the patients or with the administration of prebiotics, probiotics, and symbiotics. Similarly, different studies have demonstrated that drugs like Metformin are capable of modifying the composition of the gut microbiota, promoting changes in the biosynthesis of LPS, and the metabolism of SCFA.

Targeting the gut microbiota by Asian and Western dietary constituents: a new avenue for diabetes

Increasing numerous diabetes annually is a great concern in public health globally. Gut microbiota recently has been suggested to be an emerging organ acting as a critical regulator in diabetes. Notably, gut microbiota is closely affected through an individual's nutrient intake and dietary pattern. Moreover, the metabolites of diets through gut microbiota are closely associated with the development of diabetes. Increasing evidence has established the association of different dietary pattern with alterations of the gut microbiota profile, in particular, the Asian diet and Western diet are typically as essential components linked to the interactions between gut microbiota and induction of obesity which is a significant risk factor for diabetes. In addition, some bacteria-related therapeutic methods including probiotics, dietary short-chain fatty acids immunotherapy, and gut microbiome transfer would be applied in the clinical prevention and control diabetes. Taken together, based on current published observations, the gut microbiota may serve as regulator or targets by the Asian diet and Western diet, contributing to the prevention or induction of diabetes eventually. In general, in the upcoming future, one of the emerging strategies for the prevention and control of diabetes may modulate gut microbiota through precise dietary strategies.

Understanding the Role of Exercise in Nonalcoholic Fatty Liver Disease: ERS-Linked Molecular Pathways

Nonalcoholic fatty liver disease (NAFLD) is globally prevalent and characterized by abnormal lipid accumulation in the liver, frequently accompanied by insulin resistance (IR), enhanced hepatic inflammation, and apoptosis. Recent studies showed that endoplasmic reticulum stress (ERS) at the subcellular level underlies these featured pathologies in the development of NAFLD. As an effective treatment, exercise significantly reduces hepatic lipid accumulation and thus alleviates NAFLD. Confusingly, these benefits of exercise are associated with increased or decreased ERS in the liver. Further, the interaction between diet, medication, exercise types, and intensity in ERS regulation is more confusing, though most studies have confirmed the benefits of exercise. In this review, we focus on understanding the role of exercise-modulated ERS in NAFLD and ERS-linked molecular pathways. Moderate ERS is an essential signaling for hepatic lipid homeostasis. Higher ERS may lead to increased inflammation and apoptosis in the liver, while lower ERS may lead to the accumulation of misfolded proteins. Therefore, exercise acts like an igniter or extinguisher to keep ERS at an appropriate level by turning it up or down, which depends on diet, medications, exercise intensity, etc. Exercise not only enhances hepatic tolerance to ERS but also prevents the malignant development of steatosis due to excessive ERS.

High-fat diet-induced adipose tissue expansion occurs prior to insulin resistance in C57BL/6J mice

Background

To date, there is only scare evidence characterizing the temporal features and progression of metabolic dysfunction in high-fat diet (HFD)-fed obese mice. Hence, its specific pathogenesis remains unclear.

Methods

Sixty 6-week-old male C57BL/6J mice were randomly divided into HFD and control diet (CD) groups and sacrificed at 1, 5, 9, 13, 17, and 21 weeks, respectively. At weekly intervals, intraperitoneal glucose tolerance testing (IPGTT) and intraperitoneal insulin tolerance testing (IPITT) were performed in both groups. A detailed time course in HFD-fed mice was investigated by evaluating the initiation of glucose homeostasis impairment, dyslipidemia, systemic insulin sensitivity, monocyte chemoattractant protein-1 (MCP-1) levels, epididymal white adipose tissue (eWAT) expansion, macrophage content changes, pro-inflammatory (M1)/anti-inflammatory (M2) macrophage imbalance, lipid accumulation in the liver, and β-cell morphometry in the pancreas.

Results

In the HFD group, progressive weight gain and impairments in glucose metabolism (elevated fasting blood glucose and area under the curve (AUC) of IPGTT) were observed from the 3rd week, and a significantly elevated AUC of IPITT was first detected after week 7 of HFD feeding. As for dyslipidemia, after 9 weeks of feeding, the low-density lipoprotein cholesterol level and total cholesterol level in HFD group were significantly higher than those in the CD group (all P < 0.05), whereas no significant differences were shown in triglyceride level. Adipocyte size increased significantly in the HFD group in the 1st week, a phenotypic switch in eWAT from anti-inflammatory (M2) to pro-inflammatory (M1) macrophages was observed in the 5th week, and the metabolic inflammation was distinct in eWAT in the 9th week. Additionally, liver steatosis was considerably obvious at the 17th week and pancreatic β-cell morphometry did not change during 21 weeks of HFD feeding.

Conclusion

The eWAT expansion was detected early in HFD-induced obese mice, which occurred prior to obvious insulin resistance.

The Gut Microbiota and Its Implication in the Development of Atherosclerosis and Related Cardiovascular Diseases

The importance of gut microbiota in health and disease is being highlighted by numerous research groups worldwide. Atherosclerosis, the leading cause of heart disease and stroke, is responsible for about 50% of all cardiovascular deaths. Recently, gut dysbiosis has been identified as a remarkable factor to be considered in the pathogenesis of cardiovascular diseases (CVDs). In this review, we briefly discuss how external factors such as dietary and physical activity habits influence host-microbiota and atherogenesis, the potential mechanisms of the influence of gut microbiota in host blood pressure and the alterations in the prevalence of those bacterial genera affecting vascular tone and the development of hypertension. We will also be examining the microbiota as a therapeutic target in the prevention of CVDs and the beneficial mechanisms of probiotic administration related to cardiovascular risks. All these new insights might lead to novel analysis and CVD therapeutics based on the microbiota.

Obesity Affects the Microbiota-Gut-Brain Axis and the Regulation Thereof by Endocannabinoids and Related Mediators

The hypothalamus regulates energy homeostasis by integrating environmental and internal signals to produce behavioral responses to start or stop eating. Many satiation signals are mediated by microbiota-derived metabolites coming from the gastrointestinal tract and acting also in the brain through a complex bidirectional communication system, the microbiota–gut–brain axis. In recent years, the intestinal microbiota has emerged as a critical regulator of hypothalamic appetite-related neuronal networks. Obesogenic high-fat diets (HFDs) enhance endocannabinoid levels, both in the brain and peripheral tissues. HFDs change the gut microbiota composition by altering the Firmicutes:Bacteroidetes ratio and causing endotoxemia mainly by rising the levels of lipopolysaccharide (LPS), the most potent immunogenic component of Gram-negative bacteria. Endotoxemia induces the collapse of the gut and brain barriers, interleukin 1β (IL1β)- and tumor necrosis factor α (TNFα)-mediated neuroinflammatory responses and gliosis, which alter the appetite-regulatory circuits of the brain mediobasal hypothalamic area delimited by the median eminence. This review summarizes the emerging state-of-the-art evidence on the function of the “expanded endocannabinoid (eCB) system” or endocannabinoidome at the crossroads between intestinal microbiota, gut-brain communication and host metabolism; and highlights the critical role of this intersection in the onset of obesity.

Composite probiotics alleviate type 2 diabetes by regulating intestinal microbiota and inducing GLP-1 secretion in db/db mice

BACKGROUD/AIM

Previous studies have found that probiotic fermented camel milk has anti-diabetic effect by inducing (glucagon-like peptide-1) GLP-1 secretion. Probiotics are valuable in prevention and treatment of diabetes. As a result, our team islolated 14 probiotics from fermented camel milk. These probiotics have beneficial characteristics, but the possible anti-diabetic mechanisms remains unclear. The present study aimed to explore the possoble anti-diabetic mechanisms of 14 probiotics.

METHODS

C57BL/Ks mice were normal group. The db/db mice were randomized into five groups: model group, metformin group, liraglutide group, low-dose and high-dose probiotic group. Biochemical parameters were determined by the respective assay kits. The levels of the short-chain fatty acids (SCFAs) and microbiota were respectively determined by gas chromatography and qRT-PCR. HE staining and immunofluorescence were used for histomorphological observation. Quantitative PCR and western-blot were determined the gene and protein expression of Bax, Bcl-2, Caspase-3 and PI3K/AKT.

RESULTS

Probiotics significantly improved blood glucose and blood lipid parameters, as well as the morphological changes of pancreas, liver and kidney. Probiotics improved the gut barrier function through increasing the levels of SCFA-producing bacteria and SCFAs as well as the expression of claudin-1 and mucin-2, and decreasing Escherichia coli and LPS level. In additon, probiotics enhanced insulin secretion through glucose-triggered GLP-1 secretion by upregulating G protein-coupled receptor 43/41 (GPR43/41), proglucagon and proconvertase 1/3 activity. Forthermore, probiotics protected pancreas against apoptosis, which may be dependent on the upregulation of PI3K/AKT pathway.

CONCLUSIONS

The anti-diabetic effect of 14 probiotics in db/db mice seem to be related to an increase of SCFA-producing bacteria, the improvement of intestinal barrier function and the upregulation of GLP-1 production, and indicate these probiotics might be a good candidate to prevent and treat diabetes.

Cocoa diet modulates gut microbiota composition and improves intestinal health in Zucker diabetic rats

Cocoa supplementation improves glucose metabolism in Zucker diabetic fatty (ZDF) rats via multiple mechanisms. Furthermore, cocoa rich-diets modify the intestinal microbiota composition both in humans and rats in healthy conditions. Accordingly, we hypothesized that cocoa could interact with the gut microbiota (GM) in ZDF rats, contributing to their antidiabetic effects. Therefore, here we investigate the effect of cocoa intake on gut health and GM in ZDF diabetic rats. Male ZDF rats were fed with standard (ZDF-C) or 10% cocoa-rich diet (ZDF-Co) during 10 weeks. Zucker Lean animals (ZL) received the standard diet. Colon tissues were obtained to determine the barrier integrity and the inflammatory status of the intestine and faeces were analysed for microbial composition, short-chain fatty acids (SCFA) and lactate levels. We found that cocoa supplementation up-regulated the levels of the tight junction protein Zonula occludens-1 (ZO-1) and the mucin glycoprotein and reduced the expression of pro-inflammatory cytokines such as tumour necrosis factor-α (TNF-α), interleukin-6 (IL-6) and monocyte chemoattractant protein 1 (MCP-1) in the colon of ZDF diabetic animals. Additionally, cocoa modulated the microbial composition of the ZDF rats to values similar to those of the lean group. Importantly, cocoa treatment increased the relative abundance of acetate-producing bacteria such as Blautia and prevented the increase in the relative amount of lactate-producing bacteria (mainly Enterococcus and Lactobacillus genera) in ZDF diabetic animals. Accordingly, the total levels of SCFA (mainly acetate) increased significantly in the faeces of ZDF-Co diabetic rats. Finally, modified GM was closely associated with improved biochemical parameters related to glucose homeostasis and intestinal integrity and inflammation. These findings demonstrate for the first time that cocoa intake modifies intestinal bacteria composition towards a healthier microbial profile in diabetic animals and suggest that these changes could be associated with the improved glucose homeostasis and gut health induced by cocoa in ZDF diabetic rats.

Lactobacillus rhamnosus Reduces Blood Glucose Level through Downregulation of Gluconeogenesis Gene Expression in Streptozotocin-Induced Diabetic Rats

Some lactic acid bacteria (LAB) are observed to be potential probiotics with functional properties such as lowering fasting blood glucose (FBG), as a promising hyperglycemia management. This study investigated the ability and mechanism of Lactobacillus rhamnosus BSL and Lactobacillus rhamnosus R23 on lowering FBG in diabetic rats induced by streptozotocin (STZ). The rats were orally administered with L. rhamnosus BSL and L. rhamnosus R23 by giving 1 mL cell suspension (10⁹ CFU/mL) daily for 30 days. The body weight (BW) was recorded once in three days, and FBG was recorded once in six days. An oral glucose tolerance test (OGTT) was measured 1 week after injection with STZ and before sacrifice. Fecal samples were collected on days 0, 15, and 30 for LAB population and identification, performed by PCR detecting 16S rRNA. Oral administration of L. rhamnosus BSL and L. rhamnosus R23 decreased FBG and improved glucose tolerance via downregulation of glucose-6-phosphatase (G6pc) expression by 0.57- and 0.60-fold change, respectively (P < 0.05). The lipid profiles, BUN, creatinine, SGOT, and SGPT were significantly (P < 0.05) different between normal and diabetic rats, but they were not significantly (P > 0.05) different among diabetic rats. Both strains were effective in increasing fecal LAB population. Molecular identification of the isolated LAB from fecal sample indicated that they were able to survive and pass through the digestive tract. These results suggested that both strains have the ability to manage blood glucose level and become a promising agent to manage hyperglycemia and diabetes.