Gut microbiome and type 2 diabetes: where we are and where to go?

Metabolic networks of the human gut microbiota

The human gut microbiota controls factors that relate to human metabolism with a reach far greater than originally expected. Microbial communities and human (or animal) hosts entertain reciprocal exchanges between various inputs that are largely controlled by the host via its genetic make-up, nutrition and lifestyle. The composition of these microbial communities is fundamental to supply metabolic capabilities beyond those encoded in the host genome, and contributes to hormone and cellular signalling that support the dynamic adaptation to changes in food availability, environment and organismal development. Poor functional exchange between the microbial communities and their human host is associated with dysbiosis, metabolic dysfunction and disease. This review examines the biology of the dynamic relationship between the reciprocal metabolic state of the microbiota-host entity in balance with its environment (i.e. in healthy states), the enzymatic and metabolic changes associated with its imbalance in three well-studied diseases states such as obesity, diabetes and atherosclerosis, and the effects of bariatric surgery and exercise.

Short-Chain Fatty Acids: A Soldier Fighting Against Inflammation and Protecting From Tumorigenesis in People With Diabetes

Converging evidences showed that people with diabetes mellitus (DM) have significantly higher risk for different cancers, of which the exact mechanism underlying the association has not been fully realized. Short-chain fatty acids (SCFAs), the fermentation products of the intestinal microbiota, are an essential source for energy supply in gut epithelial cells. They have been reported to improve intestinal barrier integrity, prevent microbial translocation, and further dampen inflammation. Gut dysbiosis and reduction in SCFA-producing bacteria as well as SCFAs production in the intestine are commonly seen in metabolic disorders including DM and obesity. Moreover, inflammation can contribute to tumor initiation and progression through multiple pathways, such as enhancing DNA damage, accumulating mutations in tumor suppressor genes Tp53, and activating nuclear factor-kappa B (NF-κB) signaling pathways. Based on these facts, we hypothesize that lower levels of microbial SCFAs resulted from gut dysbiosis in diabetic individuals, enhance microbial translocation, and increase the inflammatory responses, inducing tumorigenesis ulteriorly. To this end, we will discuss protective properties of microbial SCFAs and explore the pivotal roles SCFAs played in the link of DM with cancer, so as to take early precautions to reduce the risk of cancer in patients with DM.

Genetic Basis of Tiller Dynamics of Rice Revealed by Genome-Wide Association Studies

A tiller number is the key determinant of rice plant architecture and panicle number and consequently controls grain yield. Thus, it is necessary to optimize the tiller number to achieve the maximum yield in rice. However, comprehensive analyses of the genetic basis of the tiller number, considering the development stage, tiller type, and related traits, are lacking. In this study, we sequence 219 Korean rice accessions and construct a high-quality single nucleotide polymorphism (SNP) dataset. We also evaluate the tiller number at different development stages and heading traits involved in phase transitions. By genome-wide association studies (GWASs), we detected 20 significant association signals for all traits. Five signals were detected in genomic regions near known candidate genes. Most of the candidate genes were involved in the phase transition from vegetative to reproductive growth. In particular, HD1 was simultaneously associated with the productive tiller ratio and heading date, indicating that the photoperiodic heading gene directly controls the productive tiller ratio. Multiple linear regression models of lead SNPs showed coefficients of determination (R²) of 0.49, 0.22, and 0.41 for the tiller number at the maximum tillering stage, productive tiller number, and productive tiller ratio, respectively. Furthermore, the model was validated using independent japonica rice collections, implying that the lead SNPs included in the linear regression model were generally applicable to the tiller number prediction. We revealed the genetic basis of the tiller number in rice plants during growth, By GWASs, and formulated a prediction model by linear regression. Our results improve our understanding of tillering in rice plants and provide a basis for breeding high-yield rice varieties with the optimum the tiller number.

Novel high-docosahexaenoic-acid tuna oil supplementation modulates gut microbiota and alleviates obesity in high-fat diet mice

Studies have documented the benefits of fish oil in different diseases because of its high n-3 polyunsaturated fatty acid content. However, these studies mostly used commercially available fish oil supplements with a ratio of 18/12 for eicosapentaenoic acid and docosahexaenoic acid (DHA). However, increasing DHA content for this commonly used ratio might bring out a varied metabolic effect, which have remained unclear. Thus, in this study, a novel tuna oil (TO) was applied to investigate the effect of high-DHA content on the alteration of the gut microbiota and obesity in high-fat diet mice. The results suggest that high-DHA TO (HDTO) supplementation notably ameliorates obesity and related lipid parameters and restores the expression of lipid metabolism-related genes. The benefits of TOs were derived from their modification of the gut microbiota composition and structure in mice. A high-fat diet triggered an increased Firmicutes/Bacteroidetes ratio that was remarkably restored by TOs. The number of obesity-promoting bacteria-Desulfovibrio, Paraeggerthella, Terrisporobacter, Millionella, Lachnoclostridium, Anaerobacterium, and Ruminiclostridium-was dramatically reduced. Desulfovibrio desulfuricans, Alistipes putredinis, and Millionella massiliensis, three dysbiosis-related species, were especially regulated by HDTO. Regarding the prevention of obesity, HDTO outperforms the normal TO. Intriguingly, HDTO feeding to HFD-fed mice might alter the arginine and proline metabolism of intestinal microbiota.

A Minireview on Gastrointestinal Microbiota and Radiosusceptibility

Gastrointestinal (GI) microbiota maintains a symbiotic relationship with the host and plays a key role in modulating many important biological processes and functions of the host, such as metabolism, inflammation, immune and stress response. It is becoming increasingly apparent that GI microbiota is susceptible to a wide range of environmental factors and insults, for examples, geographic location of birth, diet, use of antibiotics, and exposure to radiation. Alterations in GI microbiota link to various diseases, including radiation-induced disorders. In addition, GI microbiota composition could be used as a biomarker to estimate radiosusceptibility and radiation health risk in the host. In this minireview, we summarized the documented studies on radiation-induced alterations in GI microbiota and the relationship between GI microbiota and radiosusceptibility of the host, and mainly discussed the possible mechanisms underlying GI microbiota influencing the outcome of radiation response in humans and animal models. Furthermore, we proposed that GI microbiota manipulation may be used to reduce radiation injury and improve the health of the host.

Effects of the Traditional Chinese Medicine Tang Luo Ning on Intestinal Flora and Oxidative Stress in Diabetic Rats

Objective

To determine the effects of TLN on glycolipid metabolism, oxidative stress, and intestinal flora in diabetic rat.

Materials and Methods

Thirty-five male Sprague-Dawley (SD) rats (180-200 g) were divided into two groups. The normal group was fed a standard-chow diet, whereas, in the model group, diabetes was induced by intraperitoneal administration of streptozotocin (STZ) combined with a high-fat sucrose diet. Then, the model group was randomly allocated to four groups: DM (diabetes model) and TLNH (TLN high dose), TLNL (TLN low dose), and NAC (N-acetylcysteine). Rats in the TLNH, TLNL, and NAC groups were intragastrically administered TLN and NAC for 12 weeks. Subsequently, their weights, fasting glucose levels, serum lipids, serum insulin, serum ROS, and intestinal flora were determined.

Results

The weight and intestinal flora abundance of the DM group were significantly lower than those of the normal group, whereas their total serum cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), serum reactive oxygen species (ROS), and serum insulin (INS) levels were significantly higher than those of the normal group. TC and LDL-C levels in the TLNL group and DM group were similar, whereas FBG, INS, and ROS levels in the TLNL group were obviously lower than those in the DM group. Compared with the DM group, there was a significant increase in intestinal flora abundance in the TLNL group. At the phylum level, the ratio of Firmicutes to Bacteroidetes (core microbiota) varied in all groups. However, in the DM group, Firmicutes abundance decreased, whereas that of Bacteroidetes increased. An opposite trend was observed in the TLN-treated groups.

Conclusions

TLN, which showed a dose-dependent therapeutic effect, can effectively decrease serum lipid, serum insulin, blood glucose, and serum ROS levels. It can also rebalance the ratio of Firmicutes to Bacteroidetes. Furthermore, the low-dose TLN treatment was most efficacious.

Effects of probiotics on glycemic control and intestinal dominant flora in patients with type 2 diabetes mellitus: A protocol for systematic review and meta-analysis

BACKGROUND

With the rapid development of modern society, people's dietary structure has been changing accordingly. Diets high in salt, fat, and sugar have led to an increase in the incidence of diabetes year by year, posing a great threat to human health. More than 90% of diabetic patients have type 2 diabetes mellitus (T2DM). It is currently believed that the onset of T2DM is mainly related to factors such as genetics, insulin resistance, impaired insulin cell function, and obesity. The main mechanisms are as follows:The dominant flora of normal intestinal tract is mainly anaerobic bacteria which are beneficial to the human body. Under certain conditions, when intestinal flora is maladjusted, harmful bacteria and opportunistic bacteria become the dominant intestinal bacteria, resulting in metabolic disorders. Ingestion of probiotics can correct the imbalance of intestinal flora, and then, have a therapeutic effect on T2DM. Therefore, we designed this study to evaluate the effects of probiotics on blood glucose control and intestinal dominant flora in patients with T2DM.

METHODS

The retrieval period of meta-analysis literature is set from January 1, 1990 to September 2020. We will mainly search five English electronic databases, including Cochrane Library, Pubmed, Excerpt Medical Database (EMBASE), Science Direct and Web of Science, and search the following four Chinese databases: China Biomedical Literature Database (CBM), China National Knowledge Infrastructure (CNKI), China Science Journal Database (VIP), Wanfang Database, and so on. At the same time, the two reviewers will independently conduct research selection, data extraction and deviation risk assessment, and use Review Manager 5.3 software provided by the Cochrane Collaboration for meta-analysis and heterogeneity assessment.

RESULTS

This study will demonstrate an evidence-based review of probiotics on glycemic control and intestinal dominant flora in patients with type 2 diabetes mellitus.

CONCLUSION

This study can be used to evaluate the efficacy and safety of probiotics on glycemic control and intestinal dominant flora in patients with T2DM. REGISTRATION NUMBER:: is INPLASY202090104.

Berberine compounds improves hyperglycemia via microbiome mediated colonic TGR5-GLP pathway in db/db mice

Berberine compounds (BC), consisting of berberine (BBR), oryzanol and vitamin B₆, have been used to treat diabetes and hyperlipidemia in recent years, but the potential mechanisms under the effects have not been well determined. In this study, we evaluated the effect of BC in db/db mice, and found that BC treatment reversed the increased levels of fasting glucose and hemoglobin A1c in db/db mice, which was superior to BBR treatment. Fecal 16S rRNA gene sequencing indicated that BC increased relative abundance of microbiomes Bacteroidaceae and Clostridiaceae, which may promote conversion of primary bile acid cholic acid (CA) into secondary bile acid deoxycholic acid (DCA). Gas chromatography/mass spectrometry (GC/MS)-based metabolomics revealed that BC treatment increased fecal DCA level. Since DCA processes the potential to activate bile acid receptor-takeda G protein-coupled receptor 5 (TGR5) and induce glucagon-like peptide (GLP) secretion, we detected TGR5 expression, and found that BC-treatment significantly increased the colonic TGR5 and serum GLP-1/-2 levels in db/db mice. Modulation of TGR5-GLP pathway may also affect metabolomic profiles of serum and liver, and BC treatment showed effects on restoring the altered carbohydrate, lipid, amino acid and nucleotide metabolism. Our study suggested that BC improved hyperglycemia, the effect might attribute to the increased microbiome mediated DCA production, which up-regulated colonic TGR5 expression and GLP secretion, and improved glucose, lipid and energy metabolism in db/db mice.

Stachyose Improves the Effects of Berberine on Glucose Metabolism by Regulating Intestinal Microbiota and Short-Chain Fatty Acids in Spontaneous Type 2 Diabetic KKAy Mice

Berberine (BBR) has the beneficial effects of anti-inflammation, anti-bacteria, and anti-diabetes. The clinical application of BBR has been hindered by its poor gastrointestinal absorption. Stachyose (Sta), a prebiotic agent, improves the composition of gut microbiota and benefits for diabetes. We therefore investigated whether Sta improves the anti-diabetic actions of BBR using KKAy mice. Here, we find that the combination of BBR and Sta is more effective than BBR alone in blood glucose control, improvement of insulin resistance and islet functions, inflammatory mediators decrease, and maintenance of intestinal barrier integrity. Gut microbiota analysis demonstrates that both BBR and combined administration enhance the abundance of Bacteroidaceae and Akkermansiaceae and decrease Lachnospiraceae levels, whereas Akkermansiaceae elevation due to the administration of BBR with Sta is more significant than BBR alone. Interestingly, the proportion of Lactobacillaceae increases with combination treatment, but is diminished by BBR. Additionally, BBR with Sta significantly reduces the concentrations of fecal short-chain fatty acids compared to BBR. Collectively, these results indicate that the combination of BBR and Sta imparts better effects on the maintenance of glycemia and intestinal homeostasis than BBR alone by modulating gut microbiota and short-chain fatty acids, thereby providing a novel approach for the treatment of type 2 diabetes mellitus.

Nutritional Targeting of the Microbiome as Potential Therapy for Malnutrition and Chronic Inflammation

Homeostatic interactions with the microbiome are central for a healthy human physiology and nutrition is the main driving force shaping the microbiome. In the past decade, a wealth of preclinical studies mainly using gnotobiotic animal models demonstrated that malnutrition and chronic inflammation stress these homeostatic interactions and various microbial species and their metabolites or metabolic activities have been associated with disease. For example, the dysregulation of the bacterial metabolism of dietary tryptophan promotes an inflammatory environment and susceptibility to pathogenic infection. Clinical studies have now begun to evaluate the therapeutic potential of nutritional and probiotic interventions in malnutrition and chronic inflammation to ameliorate disease symptoms or even prevent pathogenesis. Here, we therefore summarize the recent progress in this field and propose to move further towards the nutritional targeting of the microbiome for malnutrition and chronic inflammation.

Bioinformatics and machine learning in gastrointestinal microbiome research and clinical application

The scientific community currently defines the human microbiome as all the bacteria, viruses, fungi, archaea, and eukaryotes that occupy the human body. When considering the variable locations, composition, diversity, and abundance of our microbial symbionts, the sheer volume of microorganisms reaches hundreds of trillions. With the onset of next generation sequencing (NGS), also known as high-throughput sequencing (HTS) technologies, the barriers to studying the human microbiome lowered significantly, making in-depth microbiome research accessible. Certain locations on the human body, such as the gastrointestinal, oral, nasal, and skin microbiomes have been heavily studied through community-focused projects like the Human Microbiome Project (HMP). In particular, the gastrointestinal microbiome (GM) has received significant attention due to links to neurological, immunological, and metabolic diseases, as well as cancer. Though HTS technologies allow deeper exploration of the GM, data informing the functional characteristics of microbiota and resulting effects on human function or disease are still sparse. This void is compounded by microbiome variability observed among humans through factors like genetics, environment, diet, metabolic activity, and even exercise; making GM research inherently difficult to study. This chapter describes an interdisciplinary approach to GM research with the goal of mitigating the hindrances of translating findings into a clinical setting. By applying tools and knowledge from microbiology, metagenomics, bioinformatics, machine learning, predictive modeling, and clinical study data from children with treatment-resistant epilepsy, we describe a proof-of-concept approach to clinical translation and precision application of GM research.

The Role of the Microbiome in Driving RA-Related Autoimmunity

Once referred to as "normal commensal flora" the human microbiome plays an integral role between health and disease. The host mucosal surface replete with a multitude of immune cells is a vast arena constantly sensing and responding to antigen presentation and microbial by-products. It is this key role that may allow the microbiome to prime or protect the host from autoimmune disease. Rheumatoid arthritis (RA) is a chronic, disabling inflammatory condition characterized by a complex multifactorial etiology. The presence of certain genetic markers has been proven to increase susceptibility to RA however it does not guarantee disease development. Given low concordance rates demonstrated in monozygotic twin studies there is a clear implication for the involvement of external players in RA pathogenesis. Since the historical description of rheumatoid factor, numerous additional autoantibodies have been described in the sera of RA patients. The presence of anti-cyclic citrullinated protein antibody is now a standard test, and is associated with a more severe disease course. Interestingly these antibodies are detectable in patient's sera long before the clinical signs of RA occur. The production of autoantibodies is driven by the lack of tolerance of the immune system, and how tolerance is broken is a crucial question for understanding RA development. Here we review current literature on the role of the microbiome in RA development including periodontal, gut and lung mucosa, with particular focus on proposed mechanisms of host microbiome interactions. We discuss the use of Mendelian randomization to assign causality to the microbiome and present considerations for future studies.

Gut Microbiota Resilience: Definition, Link to Health and Strategies for Intervention

The gut microbiota is a new frontier in health and disease. Not only many diseases are associated with perturbed microbiota, but an increasing number of studies point to a cause-effect relationship. Defining a healthy microbiota is not possible at the current state of our knowledge mostly because of high interindividual variability. A resilient microbiota could be used as surrogate for healthy microbiota. In addition, the gut microbiota is an “organ” with frontline exposure to environmental changes and insults. During the lifetime of an individual, it is exposed to challenges such as unhealthy diet, medications and infections. Impaired ability to bounce back to the pre-challenge baseline may lead to dysbiosis. It is therefore legitimate to postulate that maintaining a resilient microbiota may be important for health. Here we review the concept of resilience, what is known about the characteristics of a resilient microbiota, and how to assess microbiota resilience experimentally using a model of high fat diet challenge in humans. Interventions to maintain microbiota resilience can be guided by the knowledge of what microbial species or functions are perturbed by challenges, and designed to replace diminished species with probiotics, when available, or boost them with prebiotics. Fibers with multiple structures and composition can also be used to increase microbiota diversity, a characteristic of the microbiota that may be associated with resilience. We finally discuss some open questions and knowledge gaps.

The role of gut microbiota (GM) and GM-related metabolites in diabetes and obesity. A review of analytical methods used to measure GM-related metabolites in fecal samples with a focus on metabolites' derivatization step

Disruption of gut microbiota (GM) composition is increasingly related to the pathogenesis of various metabolic diseases. Additionally, GM is responsible for the production and transformation of metabolites involved in the development of metabolic disorders, such as obesity and type 2 diabetes mellitus (T2DM). The current state of knowledge regarding the composition of GM and GM-related metabolites in relation to the progress and development of obesity and T2DM is presented in this review. To understand the relationships between GM-related metabolites and the development of metabolic disorders, their accurate qualitative and quantitative measurement in biological samples is needed. Feces represent a valuable biological matrix which composition may reflect the health status of the lower gastrointestinal tract and the whole organism. Mass spectrometry (MS), mainly in combination with gas chromatography (GC) or liquid chromatography (LC), is commonly used to measure fecal metabolites. However, profiling metabolites in such a complex matrix as feces is challenging from both analytical chemistry and biochemistry standpoints. Chemical derivatization is one of the most effective methods used to overcome these problems. In this review, we provide a comprehensive summary of the derivatization methods of GM-related metabolites prior to GC-MS or LC-MS analysis, which have been published in the last five years (2015-2020). Additionally, analytical methods used for the analysis of GM-related metabolites without the derivatization step are also presented.

Probiotics, Prebiotics, Synbiotics, Postbiotics, and Obesity: Current Evidence, Controversies, and Perspectives

PURPOSE OF REVIEW

In this review, we summarize current evidence on gut microbiome and obesity; we discuss the role of probiotics, prebiotics, synbiotics, and postbiotics in obesity prevention and management; and we highlight and analyze main limitations, challenges, and controversies of their use.

RECENT FINDINGS

Overall, the majority of animal studies and meta-analyses of human studies examining the use of probiotics and synbiotics in obesity has shown their beneficial effects on weight reduction and other metabolic parameters via their involvement in gut microbiota modulation. Bifidobacterium and Lactobacillus strains are still the most widely used probiotics in functional foods and dietary supplements, but next generation probiotics, such as Faecalibacterium prausnitzii, Akkermansia muciniphila, or Clostridia strains, have demonstrated promising results. On the contrary, meta-analyses of human studies on the use of prebiotics in obesity have yielded contradictory results. In animal studies, postbiotics, mainly short-chain fatty acids, may increase energy expenditure through induction of thermogenesis in brown adipose tissue as well as browning of the white adipose tissue. The main limitations of studies on biotics in obesity include the paucity of human studies; heterogeneity among the studied subgroups regarding age, gender, and lifestyle; and use of different agents with potential therapeutic effects in different formulations, doses, ratio and different pharmacodynamics/pharmacokinetics. In terms of safety, the supplementation with prebiotics, probiotics, and synbiotics has not been associated with serious adverse effects among immune-competent individuals, with the exception of the use of probiotics and synbiotics in immunocompromised patients. Further large-scale Randomized Controlled Trials (RCTs) in humans are required to evaluate the beneficial properties of probiotics, prebiotics, synbiotics, and postbiotics; their ideal dose; the duration of supplementation; and the durability of their beneficial effects as well as their safety profile in the prevention and management of obesity.

Periodontal Disease and Periodontal Disease-Related Bacteria Involved in the Pathogenesis of Alzheimer's Disease

Alzheimer’s disease (AD) is the most common cause of dementia, and it exhibits pathological properties such as deposition of extracellular amyloid β (Aβ) and abnormally phosphorylated Tau in nerve cells and a decrease of synapses. Conventionally, drugs targeting Aβ and its related molecules have been developed on the basis of the amyloid cascade hypothesis, but sufficient effects on the disease have not been obtained in past clinical trials. On the other hand, it has been pointed out that chronic inflammation and microbial infection in the brain may be involved in the pathogenesis of AD. Recently, attention has been focused on the relationship between the periodontopathic bacterium Porphylomonas gingivalis and AD. P. gingivalis and its toxins have been detected in autopsy brain tissues from patients with AD. In addition, pathological conditions of AD are formed or exacerbated in mice infected with P. gingivalis. Compounds that target the toxins of P. gingivalis ameliorate the pathogenesis of AD triggered by P. gingivalis infection. These findings indicate that the pathological condition of AD may be regulated by controlling the bacteria in the oral cavity and the body. In the current aging society, the importance of oral and periodontal care for preventing the onset of AD will increase.

Probiotic Strains and Intervention Total Doses for Modulating Obesity-Related Microbiota Dysbiosis: A Systematic Review and Meta-analysis

Obesity is a growing health threat worldwide. Administration of probiotics in obesity has also parallelly increased but without any protocolization. We conducted a systematic review exploring the administration pattern of probiotic strains and effective doses for obesity-related disorders according to their capacity of positively modulating key biomarkers and microbiota dysbiosis. Manuscripts targeting probiotic strains and doses administered for obesity-related disorders in clinical studies were sought. MEDLINE, Scopus, Web of Science, and Cochrane Library databases were searched using keywords during the last fifteen years up to April 2020. Two independent reviewers screened titles, abstracts, and then full-text papers against inclusion criteria according to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. From 549 interventional reports identified, we filtered 171 eligible studies, from which 24 full-text assays were used for calculating intervention total doses (ITD) of specific species and strains administered. Nine of these reports were excluded in the second-step because no specific data on gut microbiota modulation was found. Six clinical trials (CT) and 9 animal clinical studies were retained for analysis of complete outcome prioritized (body mass index (BMI), adiposity parameters, glucose, and plasma lipid biomarkers, and gut hormones). Lactobacillus spp. administered were double compared to Bifidobacterium spp.; Lactobacillus as single or multispecies formulations whereas most Bifidobacteria only through multispecies supplementations. Differential factors were estimated from obese populations' vs. obesity-induced animals: ITD ratio of 2 × 106 CFU and patterns of administrations of 11.3 weeks to 5.5 weeks, respectively. Estimation of overall probiotics impact from selected CT was performed through a random-effects model to pool effect sizes. Comparisons showed a positive association between the probiotics group vs. placebo on the reduction of BMI, total cholesterol, leptin, and adiponectin. Moreover, negative estimation appeared for glucose (FPG) and CRP. While clinical trials including data for positive modulatory microbiota capacities suggested that high doses of common single and multispecies of Lactobacillus and Bifidobacterium ameliorated key obesity-related parameters, the major limitation was the high variability between studies and lack of standardized protocols. Efforts in solving this problem and searching for next-generation probiotics for obesity-related diseases would highly improve the rational use of probiotics.

Evaluation of fruta-do-lobo (Solanum lycocarpum St. Hill) starch on the growth of probiotic strains

Fruta-do-lobo (Solanum lycocarpum St. Hill) is a native fruit commonly used in Brazilian folk medicine as a hypoglycemic agent. These properties are attributed to their starch, mainly its resistant fraction. Resistant starch has shown to increases the growth of Bifidobacterium and Lactobacillus in the gut, even though not being selective for these strains. In this scenario, this study aimed to investigate the potential prebiotic activity of fruta-do-lobo starch (FLS). FLS showed around 30% of resistant starch and their prebiotic potential was evaluated with five probiotic strains L. acidophilus (LA3 and LA5), L. casei (LC01) and B. animalis (BB12) and B. lactis (BLC1) in a concentration range of 1.0-2.0% of starch. In a preliminary screening, we evaluated, during 48 h, the viability of the starch with promoting growth agent. An increase in the growth of the probiotic strains tested was observed. We also evaluated the microorganism's metabolic activity by assessing the short-chain fatty acid (SCFA) production, using the best starch growth promotion conditions (2% of FLS and strains BLC1, LA5, and LC01). As expected, MRS and lactose were preferentially metabolized by BLC1, with the highest growth rates: 0.231 and 0.224 h^-1, respectively. However, for this strain, the FLS growth rate (0.222 h^-1) was 65% higher than FOS (0.144 h^-1). Also, for LA5 FLS promoted higher growth (0.150 h^-1) than FOS (0.135 h^-1). Additionally, FLS promoted acetate production. These data are promising and indicate that FLS may have prebiotic potential and more studies need to be done with pathogenic microorganisms.

Detection and isolation of the typical gut indigenous bacteria from ddY mice fed a casein-beef tallow-based or egg yolk-based diet

The effects of whole egg on the cecal microbiome of ddY mice has been reported. To investigate the existence of susceptible indigenous bacteria (SIB) to egg yolks (EY), mice were fed a diet containing either 20% (w/w) milk casein and 17% beef tallow (CT) or 12% milk casein and 27% EY for 14 days, and then, the cecal microbiome was analyzed by 16S rRNA (V4) amplicon sequencing. To isolate the typical species in each diet group, culture-dependent viable bacterial counts were determined on Blood Liver (BL) and Gifu Anaerobic Medium (GAM) agar plates. The amplicon sequencing analysis revealed typical CT-SIB, such as Lachnospiraceae-like bacteria, and EY-SIB, such as Allobaculum-, Lactobacillus murinus-, and Bacteroides vulgatus-like bacteria. Two of the detected SIB species, L. murinus- and B. vulgatus-like bacteria, were successfully isolated from the BL and GAM agar plates and defined using a 16S rDNA BLAST search. PRACTICAL APPLICATIONS: The SIB defined in the CT and EY groups might have some effects on the nutritional and functional chemical compounds in the milk casein, beef tallow, and/or EY. Analysis of its functional properties of the isolates might develop the new and unique probiotic strains.

Type 2 Diabetes Mellitus: A Review of Multi-Target Drugs

Diabetes Mellitus (DM) is a multi-factorial chronic health condition that affects a large part of population and according to the World Health Organization (WHO) the number of adults living with diabetes is expected to increase. Since type 2 diabetes mellitus (T2DM) is suffered by the majority of diabetic patients (around 90-95%) and often the mono-target therapy fails in managing blood glucose levels and the other comorbidities, this review focuses on the potential drugs acting on multi-targets involved in the treatment of this type of diabetes. In particular, the review considers the main systems directly involved in T2DM or involved in diabetes comorbidities. Agonists acting on incretin, glucagon systems, as well as on peroxisome proliferation activated receptors are considered. Inhibitors which target either aldose reductase and tyrosine phosphatase 1B or sodium glucose transporters 1 and 2 are taken into account. Moreover, with a view at the multi-target approaches for T2DM some phytocomplexes are also discussed.

Healthy Human Gastrointestinal Microbiome: Composition and Function After a Decade of Exploration

The human gastrointestinal (GI) tract contains communities of microbes (bacteria, fungi, viruses) that vary by anatomic location and impact human health. Microbial communities differ in composition based on age, diet, and location in the gastrointestinal tract. Differences in microbial composition have been associated with chronic disease states. In terms of function, microbial metabolites provide key signals that help maintain healthy human physiology. Alterations of the healthy gastrointestinal microbiome have been linked to the development of various disease states including inflammatory bowel disease, diabetes, and colorectal cancer. While the definition of a healthy GI microbiome cannot be precisely identified, features of a healthy gut microbiome include relatively greater biodiversity and relative abundances of specific phyla and genera. Microbes with desirable functional profiles for the human host have been identified, in addition to specific metabolic features of the microbiome. This article reviews the composition and function of the healthy human GI microbiome, including the relative abundances of different bacterial taxa and the specific metabolic pathways and classes of microbial metabolites contributing to human health and disease prevention.

Gut Microbiome Profiles Are Associated With Type 2 Diabetes in Urban Africans

Gut dysbiosis has been associated with several disease outcomes including diabetes in human populations. Currently, there are no studies of the gut microbiome composition in relation to type 2 diabetes (T2D) in Africans. Here, we describe the profile of the gut microbiome in non-diabetic adults (controls) and investigate the association between gut microbiota and T2D in urban West Africans. Gut microbiota composition was determined in 291 Nigerians (98 cases, 193 controls) using fecal 16S V4 rRNA gene sequencing done on the Illumina MiSeq platform. Data analysis of operational taxonomic units (OTU) was conducted to describe microbiome composition and identify differences between T2D and controls. The most abundant phyla were Firmicutes, Actinobacteria, and Bacteroidetes. Clostridiaceae, and Peptostreptococcaceaea were significantly lower in cases than controls (p < 0.001). Feature selection analysis identified a panel of 18 OTUs enriched in cases that included Desulfovibrio piger, Prevotella, Peptostreptococcus, and Eubacterium. A panel of 17 OTUs that was enriched in the controls included Collinsella, Ruminococcus lactaris, Anaerostipes, and Clostridium. OTUs with strain-level annotation showing the largest fold-change included Cellulosilyticum ruminicola (log₂FC = −3.1; p = 4.2 × 10⁻⁵), Clostridium paraputrificum (log₂FC = −2.5; p = 0.005), and Clostridium butyricum (log₂FC = −1.76; p = 0.01), all lower in cases. These findings are notable because supplementation with Clostridium butyricum and Desulfovibrio piger has been shown to improve hyperglycemia and reduce insulin resistance in murine models. This first investigation of gut microbiome and diabetes in urban Africans shows that T2D is associated with compositional changes in gut microbiota highlighting the possibility of developing strategies to improve glucose control by modifying bacterial composition in the gut.

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.

Berberine for prevention of dementia associated with diabetes and its comorbidities: A systematic review

BACKGROUND

A growing number of epidemiological studies indicate that metabolic syndrome (MetS) and its associated features play a key role in the development of certain degenerative brain disorders, including Alzheimer's disease and vascular dementia. Produced by several different medicinal plants, berberine is a bioactive alkaloid with a wide range of pharmacological effects, including antidiabetic effects. However, it is not clear whether berberine could prevent the development of dementia in association with diabetes.

OBJECTIVE

To give an overview of the therapeutic potential of berberine as a treatment for dementia associated with diabetes.

SEARCH STRATEGY

Database searches A and B were conducted using PubMed and ScienceDirect. In search A, studies on berberine's antidementia activities were identified using "berberine" and "dementia" as search terms. In search B, recent studies on berberine's effects on diabetes were surveyed using "berberine" and "diabetes" as search terms.

INCLUSION CRITERIA

Clinical and preclinical studies that investigated berberine's effects associated with MetS and cognitive dysfunction were included.

DATA EXTRACTION AND ANALYSIS

Data from studies were extracted by one author, and checked by a second; quality assessments were performed independently by two authors.

RESULTS

In search A, 61 articles were identified, and 22 original research articles were selected. In search B, 458 articles were identified, of which 101 were deemed relevant and selected. Three duplicates were removed, and a total of 120 articles were reviewed for this study. The results demonstrate that berberine exerts beneficial effects directly in the brain: enhancing cholinergic neurotransmission, improving cerebral blood flow, protecting neurons from inflammation, limiting hyperphosphorylation of tau and facilitating β-amyloid peptide clearance. In addition, evidence is growing that berberine is effective against diabetes and associated disorders, such as atherosclerosis, cardiomyopathy, hypertension, hepatic steatosis, diabetic nephropathy, gut dysbiosis, retinopathy and neuropathy, suggesting indirect benefits for the prevention of dementia.

CONCLUSION

Berberine could impede the development of dementia via multiple mechanisms: preventing brain damages and enhancing cognition directly in the brain, and indirectly through alleviating risk factors such as metabolic dysfunction, and cardiovascular, kidney and liver diseases. This study provided evidence to support the value of berberine in the prevention of dementia associated with MetS.

Yeast β-glucan, a potential prebiotic, showed a similar probiotic activity to inulin

β-Glucan, an economical by-product of yeast,  showed a similar probiotic activity to inulinw, which is expected to be a potential prebiotic for the modulation of gut microbiota.

Microbiota in pancreatic health and disease: the next frontier in microbiome research

Diseases intrinsic to the pancreas such as pancreatitis, pancreatic cancer and type 1 diabetes mellitus impart substantial health and financial burdens on society but identification of novel mechanisms contributing to these pathologies are slow to emerge. A novel area of research suggests that pancreatic-specific disorders might be modulated by the gut microbiota, either through a local (direct pancreatic influence) or in a remote (nonpancreatic) fashion. In this Perspectives, we examine literature implicating microorganisms in diseases of the pancreas, specifically pancreatitis, type 1 diabetes mellitus and pancreatic ductal adenocarcinoma. We also discuss evidence of an inherent pancreatic microbiota and the influence of the intestinal microbiota as it relates to disease association and development. In doing so, we address pitfalls in the current literature and areas of investigation that are needed to advance a developing field of research that has clinical potential to reduce the societal burden of pancreatic diseases.

Understanding the Role of the Gut Microbiome and Microbial Metabolites in Obesity and Obesity-Associated Metabolic Disorders: Current Evidence and Perspectives

PURPOSE

In this review, we summarize current evidence on the gut microbiome and microbial metabolites in relation to obesity and obesity-associated metabolic disorders. Special emphasis is given on mechanisms interconnecting gut microbiome and microbial metabolites with metabolic disorders as well as on potential preventive and therapeutic perspectives with a "bench to bedside" approach.

RECENT FINDINGS

Recent data have highlighted the role of gut dysbiosis in the etiology and pathogenesis of metabolic disorders, including obesity, metabolic syndrome, type 2 diabetes mellitus, and non-alcoholic fatty liver disease. Overall, most studies have demonstrated a reduction in gut microbiome diversity and richness in obese subjects, but there is still much debate on the exact microbial signature of a healthy or an obese gut microbiome. Despite the controversial role of an altered gut microbiome as a cause or consequence of obesity in human studies, numerous animal studies and certain human studies suggest beneficial metabolic effects of certain microbial intestinal metabolites, such as butyrate, that could be used in the prevention and treatment of obesity and its comorbidities. More randomized controlled trials and larger prospective studies including well-defined cohorts as well as a multi-omics approach are warranted to better identify the associations between the gut microbiome, microbial metabolites, and obesity and its metabolic complications.

Discovery of Food-Derived Dipeptidyl Peptidase IV Inhibitory Peptides: A Review

Diabetes is a chronic metabolic disorder which leads to high blood sugar levels over a prolonged period. Type 2 diabetes mellitus (T2DM) is the most common form of diabetes and results from the body's ineffective use of insulin. Over ten dipeptidyl peptidase IV (DPP-IV) inhibitory drugs have been developed and marketed around the world in the past decade. However, owing to the reported adverse effects of the synthetic DPP-IV inhibitors, attempts have been made to find DPP-IV inhibitors from natural sources. Food-derived components, such as protein hydrolysates (peptides), have been suggested as potential DPP-IV inhibitors which can help manage blood glucose levels. This review focuses on the methods of discovery of food-derived DPP-IV inhibitory peptides, including fractionation and purification approaches, in silico analysis methods, in vivo studies, and the bioavailability of these food-derived peptides. Moreover, food-derived DPP-IV inhibitory peptides discovered during this decade are listed and distributed in a 3D scatter plot graph based on their IC50, molecular weight, and grand average of hydropathicity values, which can help us to understand the relationship between the features of the peptides and their activities.