Role of gut microbiota in type 2 diabetes pathophysiology

Gut microbiota as the critical correlation of polycystic ovary syndrome and type 2 diabetes mellitus

Gut microbiota forms a symbiotic relationship with the host and maintains the ecological balance of the internal and external environment of the human body. However, dysbiosis of the gut microbiota and immune deficiency, as well as environmental changes, can destroy the host-microbial balance, leading to the occurrence of a variety of diseases, such as polycystic ovary syndrome (PCOS), type 2 diabetes mellitus (T2DM), and obesity. Meanwhile, diseases can also affect gut microbiota, forming a vicious cycle. The role of the intestinal microbiota in different diseases have been proven by several studies; however, as a common target of PCOS and T2DM, there are few reports on the treatment of different diseases through the regulation of intestinal microbiota as the critical correlation. This review analyzed the common mechanisms of intestinal microbiota in PCOS and T2DM, including the dysbiosis of gut microbiota, endotoxemia, short-chain fatty acids, biotransformation of bile acids, and synthesis of amino acid in regulating insulin resistance, obesity, chronic inflammation, and mitochondrial dysfunction. The possible therapeutic effects of probiotics and/or prebiotics, fecal microbiota transplantation, bariatric surgery, dietary intervention, drug treatment, and other treatments targeted at regulating intestinal microbiota were also elucidated.

Discovering Potential Taxonomic Biomarkers of Type 2 Diabetes From Human Gut Microbiota via Different Feature Selection Methods

Human gut microbiota is a complex community of organisms including trillions of bacteria. While these microorganisms are considered as essential regulators of our immune system, some of them can cause several diseases. In recent years, next-generation sequencing technologies accelerated the discovery of human gut microbiota. In this respect, the use of machine learning techniques became popular to analyze disease-associated metagenomics datasets. Type 2 diabetes (T2D) is a chronic disease and affects millions of people around the world. Since the early diagnosis in T2D is important for effective treatment, there is an utmost need to develop a classification technique that can accelerate T2D diagnosis. In this study, using T2D-associated metagenomics data, we aim to develop a classification model to facilitate T2D diagnosis and to discover T2D-associated biomarkers. The sequencing data of T2D patients and healthy individuals were taken from a metagenome-wide association study and categorized into disease states. The sequencing reads were assigned to taxa, and the identified species are used to train and test our model. To deal with the high dimensionality of features, we applied robust feature selection algorithms such as Conditional Mutual Information Maximization, Maximum Relevance and Minimum Redundancy, Correlation Based Feature Selection, and select K best approach. To test the performance of the classification based on the features that are selected by different methods, we used random forest classifier with 100-fold Monte Carlo cross-validation. In our experiments, we observed that 15 commonly selected features have a considerable effect in terms of minimizing the microbiota used for the diagnosis of T2D and thus reducing the time and cost. When we perform biological validation of these identified species, we found that some of them are known as related to T2D development mechanisms and we identified additional species as potential biomarkers. Additionally, we attempted to find the subgroups of T2D patients using k-means clustering. In summary, this study utilizes several supervised and unsupervised machine learning algorithms to increase the diagnostic accuracy of T2D, investigates potential biomarkers of T2D, and finds out which subset of microbiota is more informative than other taxa by applying state-of-the art feature selection methods.

Mahalanobis distance, a novel statistical proxy of homeostasis loss is longitudinally associated with risk of type 2 diabetes

Background

The potential role of individual plasma biomarkers in the pathogenesis of type 2 diabetes (T2D) has been broadly studied, but the impact of biomarkers interaction remains underexplored. Recently, the Mahalanobis distance (MD) of plasma biomarkers has been proposed as a proxy of physiological dysregulation. Here we aimed to investigate whether the MD calculated from circulating biomarkers is prospectively associated with development of T2D.

Methods

We calculated the MD of the Principal Components (PCs) integrating the information of 32 circulating biomarkers (comprising inflammation, glycemic, lipid, microbiome and one-carbon metabolism) measured in 6247 participants of the PREVEND study without T2D at baseline. Cox proportional-hazards regression analyses were performed to study the association of MD with T2D development.

Findings

After a median follow-up of 7·3 years, 312 subjects developed T2D. The overall MD (mean (SD)) was higher in subjects who developed T2D compared to those who did not: 35·65 (26·67) and 30.75 (27·57), respectively (P = 0·002). The highest hazard ratio (HR) was obtained using the MD calculated from the first 31 PCs (per 1 log-unit increment) (1·72 (95% CI 1·42,2·07), P < 0·001). Such associations remained after the adjustment for age, sex, plasma glucose, parental history of T2D, lipids, blood pressure medication, and BMI (HR_adj 1·37 (95% CI 1·11,1·70), P = 0·004).

Interpretation

Our results are in line with the premise that MD represents an estimate of homeostasis loss. This study suggests that MD is able to provide information about physiological dysregulation also in the pathogenesis of T2D.

Funding

The Dutch Kidney Foundation (Grant E.033).

Sargassum fusiforme Alginate Relieves Hyperglycemia and Modulates Intestinal Microbiota and Metabolites in Type 2 Diabetic Mice

Sargassum fusiforme alginate (SF-Alg) possess many pharmacological activities, including hypoglycemic and hypolipidemic. However, the hypoglycemic mechanisms of SF-Alg remain unclear due to its low bioavailability. In this study, we evaluated the therapeutic effect of SF-Alg on high-fat diet (HFD)/streptozotocin (STZ)-induced type 2 diabetes (T2D) mice. SF-Alg intervention was found to significantly reduce fasting blood glucose (FBG), triglycerides (TG), and total cholesterol (TC), while increasing high-density lipoprotein cholesterol (HDL-c) and improving glucose tolerance. In addition, administrating SF-Alg to diabetic mice moderately attenuated pathological changes in adipose, hepatic, and heart tissues as well as skeletal muscle, and diminished oxidative stress. To probe the underlying mechanisms, we further analyzed the gut microbiota using 16S rRNA amplicon sequencing, as well as metabolites by non-targeted metabolomics. Here, SF-Alg significantly increased some benign bacteria (Lactobacillus, Bacteroides, Akkermansia Alloprevotella, Weissella and Enterorhabdus), and significantly decreased harmful bacteria (Turicibacter and Helicobacter). Meanwhile, SF-Alg dramatically decreased branched-chain amino acids (BCAAs) and aromatic amino acids (AAAs) in the colon of T2D mice, suggesting a positive benefit of SF-Alg as an adjvant agent for T2D.

Roles of α‑synuclein in gastrointestinal microbiome dysbiosis‑related Parkinson's disease progression (Review)

Parkinson's disease (PD) is the second most common neurodegenerative disease amongst the middle-aged and elderly populations. Several studies have confirmed that the microbiota-gut-brain axis (MGBA) serves a key role in the pathogenesis of PD. Changes to the gastrointestinal microbiome (GM) cause misfolding and abnormal aggregation of α-synuclein (α-syn) in the intestine. Abnormal α-syn is not eliminated via physiological mechanisms and is transported into the central nervous system (CNS) via the vagus nerve. The abnormal levels of α-syn aggregate in the substantia nigra pars compacta, not only leading to the formation of eosinophilic Lewis Bodies in the cytoplasm and mitochondrial dysfunction in dopaminergic (DA) neurons, but also leading to the stimulation of an inflammatory response in the microglia. These pathological changes result in an increase in oxidative stress (OS), which triggers nerve cell apoptosis, a characteristic of PD. This increase in OS further oxidizes and intensifies abnormal aggregation of α-syn, eventually forming a positive feedback loop. The present review discusses the abnormal accumulation of α-syn in the intestine caused by the GM changes and the increased levels of α-syn transport to the CNS via the MGBA, resulting in the loss of DA neurons and an increase in the inflammatory response of microglial cells in the brain of patients with PD. In addition, relevant clinical therapeutic strategies for improving the GM and reducing α-syn accumulation to relieve the symptoms and progression of PD are described.

Vascepa protects against high-fat diet-induced glucose intolerance, insulin resistance, and impaired β-cell function

Omega-3 fatty acid prescription drugs, Vascepa (≥96% eicosapentaenoic acid [EPA] ethyl ester) and Lovaza (46.5% EPA and 37.5% docosahexaenoic acid ethyl ester) are known therapeutic regimens to treat hypertriglyceridemia. However, their impact on glucose homeostasis, progression to type 2 diabetes, and pancreatic beta cell function are not well understood. In the present study, mice were treated with Vascepa or Lovaza for one week prior to six weeks of high-fat diet feeding. Vascepa but not Lovaza led to reduced insulin resistance, reduced fasting insulin and glucose, and improved glucose intolerance. Vascepa improved beta cell function, reduced liver triglycerides with enhanced expression of hepatic fatty acid oxidation genes, and altered microbiota composition. Vascepa has protective effects on diet-induced insulin resistance and glucose intolerance in mice.

Paternal high protein diet modulates body composition, insulin sensitivity, epigenetics, and gut microbiota intergenerationally in rats

Mounting evidence demonstrates that paternal diet programs offspring metabolism. However, the contribution of a pre-conception paternal high protein (HP) diet to offspring metabolism, gut microbiota, and epigenetic changes remains unclear. Here we show that paternal HP intake in Sprague Dawley rats programs protective metabolic outcomes in offspring. Compared to paternal high fat/sucrose (HF/S), HP diet improved body composition and insulin sensitivity and improved circulating satiety hormones and cecal short-chain fatty acids compared to HF/S and control diet (P < .05). Further, using 16S rRNA gene sequencing to assess gut microbial composition, we observed increased alpha diversity, distinct bacterial clustering, and increased abundance of Bifidobacterium, Akkermansia, Bacteroides, and Marvinbryantia in HP fathers and/or male and female adult offspring. At the epigenetic level, DNMT1and 3b expression was altered intergenerationally. Our study identifies paternal HP diet as a modulator of gut microbial composition, epigenetic markers, and metabolic function intergenerationally.

Nodal immune flare mimics nodal disease progression following neoadjuvant immune checkpoint inhibitors in non-small cell lung cancer

Radiographic imaging is the standard approach for evaluating the disease involvement of lymph nodes in patients with operable NSCLC although the impact of neoadjuvant immune checkpoint inhibitors (ICIs) on lymph nodes has not yet been characterized. Herein, we present an ad hoc analysis of the NEOSTAR trial (NCT03158129) where we observed a phenomenon we refer to as “nodal immune flare” (NIF) in which patients treated with neoadjuvant ICIs demonstrate radiologically abnormal nodes post-therapy that upon pathological evaluation are devoid of cancer and demonstrate de novo non-caseating granulomas. Abnormal lymph nodes are analyzed by computed tomography and ¹⁸F-fluorodeoxyglucose positron emission tomography/computer tomography to evaluate the size and the maximum standard uptake value post- and pre-therapy in NEOSTAR and an independent neoadjuvant chemotherapy cohort. NIF occurs in 16% (7/44) of patients treated with ICIs but in 0% (0/28) of patients after neoadjuvant chemotherapy. NIF is associated with an inflamed nodal immune microenvironment and with fecal abundance of genera belonging to the family Coriobacteriaceae of phylum Actinobacteria, but not with tumor responses or treatment-related toxicity. Our findings suggest that this apparent radiological cancer progression in lymph nodes may occur due to an inflammatory response after neoadjuvant immunotherapy, and such cases should be evaluated by pathological examination to distinguish NIF from true nodal progression and to ensure appropriate clinical treatment planning.

Granulomatous/sarcoid-like lesions have been reported in patients treated with immune checkpoint inhibitors (ICIs). Here the authors report the occurrence of “nodal immune flare”, an apparent radiological cancer progression in the nodes characterized by the absence of cancer and the presence of non-caseating granulomas, in patients with non-small cell lung cancer following neoadjuvant ICI treatment.

Dietary supplementation with mung bean coat alleviates the disorders in serum glucose and lipid profile and modulates gut microbiota in high-fat diet and streptozotocin-induced prediabetic mice

As amajor by-product of mung bean processing, mung bean coat (MBC), which is rich in polyphenols and dietary fiber, is deemed to be mainly responsible for the health benefits of mung bean. However, its beneficial effects on the hyperglycemia, hyperlipidemia, and gut microbiota composition in prediabetic mice is not fully understood. The objective of this study was to investigate the efficacy of MBC in alleviating high-fat diet and streptozotocin-induced prediabetes. Herein, compared with the model control, dietary supplementation with MBC (3%, w/w) for 12 weeks significantly decreased the fasting blood glucose (24.60%), total cholesterol (15.72%), triglyceride (14.41%), and low-density lipoprotein cholesterol (22.45%). Furthermore, the improvements in glucose tolerance were reflected in the reduction of the area under the curve (AUC) and incremental AUC by approximately 23.08% and 51.18%, respectively. 16S rRNA gene sequencing of fecal microbiota suggested that MBC promoted the enrichment of beneficial bacteria (Roseburia and Bifidobacterium) and the production of short-chain fatty acids. All of the results from this study provided a scientific reference for avoiding the functional ingredients waste of MBC and expanding its application value.

Gut dysbiosis, inflammation and type 2 diabetes in mice using synthetic gut microbiota from diabetic humans

The study was aimed to assess impact of high fat diet (HFD) and synthetic human gut microbiota (GM) combined with HFD and chow diet (CD) in inducing type-2 diabetes (T2D) using mice model. To our knowledge, this is the first study using selected human GM transplantation via culture based method coupled dietary modulation in mice for in vivo establishment of inflammation leading to T2D and gut dysbiosis. Twenty bacteria (T2D1-T2D20) from stool samples of confirmed T2D subjects were found to be morphologically different and subjected to purification on different media both aerobically and anerobically, which revealed seven bacteria more common among 20 isolates on the basis of biochemical characterization. On the basis of 16S rRNA gene sequencing, these seven isolates were identified as Bacteroides stercoris (MT152636), Lactobacillus acidophilus (MT152637), Lactobacillus salivarius (MT152638), Ruminococcus bromii (MT152639), Klebsiella aerogenes (MT152640), Bacteroides fragilis (MT152909), Clostridium botulinum (MT152910). The seven isolates were subsequently used as synthetic gut microbiome (GM) for their role in inducing T2D in mice. Inbred strains of albino mice were divided into four groups and were fed with CD, HFD, GM+HFD and GM+CD. Mice receiving HFD and GM+modified diet (CD/HFD) showed highly significant (P<0.05) increase in weight and blood glucose concentration as well as elevated level of inflammatory cytokines (TNF-α, IL-6, and MCP-1) compared to mice receiving CD only. The 16S rRNA gene sequencing of 11 fecal bacteria obtained from three randomly selected animals from each group revealed gut dysbiosis in animals receiving GM. Bacterial strains including Bacteroides gallinarum (MT152630), Ruminococcus bromii (MT152631), Lactobacillus acidophilus (MT152632), Parabacteroides gordonii (MT152633), Prevotella copri (MT152634) and Lactobacillus gasseri (MT152635) were isolated from mice treated with GM+modified diet (HFD/CD) compared to strains Akkermansia muciniphila (MT152625), Bacteriodes sp. (MT152626), Bacteroides faecis (MT152627), Bacteroides vulgatus (MT152628), Lactobacillus plantarum (MT152629) which were isolated from mice receiving CD/HFD. In conclusion, these findings suggest that constitution of GM and diet plays significant role in inflammation leading to onset or/and possibly progression of T2D. .

The role of autoimmunity in the pathophysiology of type 2 diabetes: Looking at the other side of the moon

Efforts to unravel the pathophysiological mechanisms of type 2 diabetes (T2D) have been traditionally trapped into a metabolic perspective. However, T2D is a phenotypically and pathophysiologically heterogenous disorder, and the need for a tailored approach in its management is becoming increasingly evident. There is emerging evidence that irregular immune responses contribute to the development of hyperglycemia in T2D and, inversely, that insulin resistance is a component of the pathogenesis of autoimmune diabetes. Nevertheless, it has not yet been fully elucidated to what extent the presence of conventional autoimmune markers, such as autoantibodies, in subjects with T2D might affect the natural history of the disease and particularly each response to various treatments. The challenge for future research in the field is the discovery of novel genetic, molecular, or phenotypical indicators that would enable the characterization of specific subpopulations of people with T2D who would benefit most from the addition of immunomodulatory therapies to standard glucose-lowering treatment. This narrative review aims to discuss the plausible mechanisms through which the immune system might be implicated in the development of metabolic disturbances in T2D and obesity and explore a potential role of immunotherapy in the future management of the disorder and its complications.

Manipulation of intestinal microbiome as potential treatment for insulin resistance and type 2 diabetes

PURPOSE

Increasing evidence suggests that the intestinal microbiome (IM) and bacterial metabolites may influence glucose homeostasis, energy expenditure and the intestinal barrier integrity and lead to the presence of systemic low-grade inflammation, all of which can contribute to insulin resistance (IR) and type 2 diabetes (T2D). The purpose of this review is to explore the role of the IM and bacterial metabolites in the pathogenesis and treatment of these conditions.

RESULTS

This review summarizes research focused on how to modulate the IM through diet, prebiotics, probiotics, synbiotics and fecal microbiota transplant in order to treat IR and T2D.

CONCLUSION

There is an abundance of evidence suggesting a role for IM in the pathogenesis of IR and T2D based on reviewed studies using various methods to modulate IM and metabolites. However, the results are inconsistent. Future research should further assess this relationship.

Gut Microbiota in Bone Health and Diabetes

PURPOSE OF REVIEW

Patients with diabetes mellitus (DM) are at increased risk of developing osteopathogenesis and skeletal fragility. The role of the gut microbiota in both DM and osteopathy is not fully explored and may be involved in the pathology of both diseases.

RECENT FINDINGS

Gut microbiota alterations have been observed in DM and osteopathogenic disorders as compared with healthy controls, such as significantly lower abundance of Prevotella and higher abundance of Lactobacillus, with a diminished bacterial diversity. Other overlapping gastro-intestinal features include the loss of intestinal barrier function with translocation of bacterial metabolites to the blood stream, induction of immunological deficits and changes in hormonal and endocrinal signalling, which may lead to the development of diabetic osteopathy. Signalling pathways involved in both DM and osteopathy are affected by gut bacteria and their metabolites. Future studies should focus on gut microbiota involvement in both diseases.

Gut microbiota in patients with newly diagnosed acromegaly: a pilot cross-sectional study

PURPOSE

Microbiota has crucial biological importance for human well-being. Bidirectional interaction exists between microbiota and the host, and there have been no studies investigating this interaction in patients with acromegaly. We aimed to analyze the composition of microbiota in patients with newly diagnosed acromegaly.

METHOD

Stool samples were obtained from the patients with newly diagnosed acromegaly in the Endocrinology Clinic of Erciyes University Medical School. The composition of microbiota was analyzed, and the results were compared to healthy volunteers matched to the patients in terms of age, gender and body mass index.

RESULTS

Seven patients (three male, four female) with a mean age of 48 ± 17.6 years were included in the study. The stool analysis revealed a significantly lower bacterial diversity in the patients with acromegaly. Bacteroidetes phylum was predominating in the patient group, and Firmicutes/Bacteroidetes ratio was altered significantly. Bifidobacterium, Collinsella, Bacteroides, Butyricimonas, Clostridium, Oscillospira, and Dialister were predominating in the control group.

CONCLUSION

The gut microbiota is significantly altered in patients with newly diagnosed acromegaly. Further prospective studies are needed to elucidate the causative relationship between acromegaly, colorectal pathologies, and microbial alterations.

Probiotics in Prevention and Treatment of COVID-19: Current Perspective and Future Prospects

Saving lives and flattening the curve are the foremost priorities during the ongoing pandemic spread of SARS-CoV-2. Developing cutting-edge technology and collating available evidence would support frontline health teams. Nutritional adequacy improves general health and immunity to prevent and assuage infections. This review aims to outline the potential role of probiotics in fighting the COVID-19 by covering recent evidence on the association between microbiota, probiotics, and COVID-19, the role of probiotics as an immune-modulator and antiviral agent. The high basic reproduction number (R0) of SARS-CoV-2, absence of conclusive remedies, and the pleiotropic effect of probiotics in fighting influenza and other coronaviruses together favour probiotics supplements. However, further support from preclinical and clinical studies and reviews outlining the role of probiotics in COVID-19 are critical. Results are awaited from many ongoing clinical trials investigating the benefits of probiotics in COVID-19.

Molecular Aspects of Lifestyle and Environmental Effects in Patients With Diabetes: JACC Focus Seminar

Diabetes is characterized as an integrated condition of dysregulated metabolism across multiple tissues, with well-established consequences on the cardiovascular system. Recent advances in precision phenotyping in biofluids and tissues in large human observational and interventional studies have afforded a unique opportunity to translate seminal findings in models and cellular systems to patients at risk for diabetes and its complications. Specifically, techniques to assay metabolites, proteins, and transcripts, alongside more recent assessment of the gut microbiome, underscore the complexity of diabetes in patients, suggesting avenues for precision phenotyping of risk, response to intervention, and potentially novel therapies. In addition, the influence of external factors and inputs (eg, activity, diet, medical therapies) on each domain of molecular characterization has gained prominence toward better understanding their role in prevention. Here, the authors provide a broad overview of the role of several of these molecular domains in human translational investigation in diabetes.

Functional dissection of the phosphotransferase system provides insight into the prevalence of Faecalibacterium prausnitzii in the host intestinal environment

Faecalibacterium prausnitzii is a dominant member of healthy human colon microbiota, regarded as a beneficial gut bacterium due to its ability to produce anti-inflammatory substances. However, little is known about how F. prausnitzii utilizes the nutrients present in the human gut, influencing its prevalence in the host intestinal environment. The phosphoenolpyruvate (PEP):carbohydrate phosphotransferase system (PTS) is a widely distributed and highly efficient carbohydrate transport system found in most bacterial species that catalyses the simultaneous phosphorylation and import of cognate carbohydrates; its components play physiological roles through interaction with other regulatory proteins. Here, we performed a systematic analysis of the 16 genes encoding putative PTS components (2 enzyme I, 2 HPr, and 12 enzyme II components) in F. prausnitzii A2-165. We identified the general PTS components responsible for the PEP-dependent phosphotransfer reaction and the sugar-specific PTS components involved in the transport of two carbohydrates, N-acetylglucosamine and fructose, among five enzyme II complexes. We suggest that the dissection of the functional PTS in F. prausnitzii may help to understand how this species outcompetes other bacterial species in the human intestine.

The effect of sorghum consumption on markers of chronic disease: A systematic review

Sorghum requires fewer inputs for sustainable cultivation in harsh climates and has the potential to be utilized in modern food product innovations. Moreover, consumption of sorghum may elicit favorable health effects similar to other commonly consumed cereals, like wheat. Animal and human research exploring health effects of sorghum consumption indicates potential beneficial effects on blood glucose and lipid regulation, oxidative stress modulation, appetite regulation and weight management. However, a recent appraisal of the strength of evidence has not been conducted. Therefore, this study aims to evaluate the effects of sorghum consumption on metabolic indicators of chronic disease, including blood lipid and blood glucose levels, markers of oxidative stress, and factors associated with weight management. Using CINAHL, Cochrane Library, PubMed and MEDLINE databases, a systematic review of intervention studies published up to May 2020 was conducted and 16 interventional studies met the criteria for inclusion. Evidence for favorable effects of sorghum consumption on indicators of chronic disease, including blood glucose responses, markers of oxidative stress, satiety measures and weight management was demonstrated. Evidence from this systematic review may assist to promote sorghum's potential health benefits globally, including in food markets where it is underutilized, stimulating more sorghum-based food innovations in the future.

Hemicellulose-Derived Oligosaccharides: Emerging Prebiotics in Disease Alleviation

The gut microbiota in the human body is an important component that plays a pivotal role in the ability of the host to prevent diseases and recover from these diseases. If the human microbiome changes for any reason, it affects the overall functioning of the host. Healthy and vigorous gut microbiota require dietary fiber supplementation. Recently, oligosaccharides have been found to play a significant role in the modulation of microbiota. Several such oligosaccharides, i.e., xylooligosaccharides (XOS), mannooligosaccharides (MOS), and arabino-xylooligosaccharides (AXOS), are derived from hemicellulosic macromolecules such as xylan, mannan, and arabino-xylan, respectively. These oligosaccharides serve as substrates for the probiotic production of health-promoting substances (short-chain fatty acids, branched chain amino acids etc.), which confer a variety of health benefits, including the prevention of some dreaded diseases. Among hemicellulose-derived oligosaccharides (HDOs), XOS have been largely explored, whereas, studies on MOS and AXOS are currently underway. HDOs, upon ingestion, help reduce morbidities by lowering populations of harmful or pathogenic bacteria. The ATP-binding cassette (ABC) transporters are mainly utilized for the uptake of oligosaccharides in probiotics. Butyrate generated by the selective fermentation of oligosaccharides, along with other short-chain fatty acids, reduces gut inflammation. Overall, oligosaccharides derived from hemicelluloses show a similar potential as conventional prebiotics and can be supplemented as functional foods. This review summarizes the role of HDOs in the alleviation of autoimmune diseases (inflammatory bowel disease, Crohn's disease), diabetes, urinary tract infection, cardiovascular diseases, and antimicrobial resistance (AMR) through the modulation of the gut microbiota. The mechanism of oligosaccharide utilization and disease mitigation is also explained.

Lactobacillus casei LC89 exerts antidiabetic effects through regulating hepatic glucagon response and gut microbiota in type 2 diabetic mice

Previous study suggests that Lactobacillus casei exhibits antihyperglycemic activity, however, the molecular mechanism of this has yet to be elucidated. Here, the anti-diabetic effects and underlying mechanisms of Lactobacillus casei LC89 are investigated in type 2 diabetes mellitus (T2DM) mice, which was induced by a high-fat diet (HFD) with streptozotocin (100 mg per kg BW). The results show that LC89 at a dose of 109 CFU day-1 decreases fasting blood glucose (FBG) and insulin levels by 35.12% and 28.37%, respectively, compared to the diabetes control (DC) group. Moreover, LC89 treatment improved the insulin resistance index (HOMA-IR), serum lipid profiles and inflammation cytokines. The real-time polymerase chain reaction indicated that LC89 markedly downregulates the mRNA expression of hepatic glucagon (GCG), glucagon receptor (GCGR), phosphoenolpyruvate carboxykinase (PEPCK) and glucose-6-phosphatase (G6Pase). Meanwhile, LC89 significantly decreases the abundance of Odoribacter, but increases the Alloprevotella, Bacteroides, Parabacteroides and Ruminococcus content. Therefore, LC89 plays a positive role in alleviating T2DM by regulating gut microbiota and glucagon signal pathway-related genes, and it may be a beneficial dietary supplement to regulate glucose metabolism in T2DM.

Dietary advanced glycation end-products elicit toxicological effects by disrupting gut microbiome and immune homeostasis

The aging immune system is characterized by a low-grade chronic systemic inflammatory state ("inflammaging") marked by elevated serum levels of inflammatory molecules such as interleukin (IL)-6 and C-reactive protein (CRP). These inflammatory markers were also reported to be strong predictors for the development/severity of Type 2 diabetes, obesity, and COVID-19. The levels of these markers have been positively associated with those of advanced glycation end-products (AGEs) generated via non-enzymatic glycation and oxidation of proteins and lipids during normal aging and metabolism. Based on the above observations, it is clinically important to elucidate how dietary AGEs modulate inflammation and might thus increase the risk for aging-exacerbated diseases. The present narrative review discusses the potential pro-inflammatory properties of dietary AGEs with a focus on the inflammatory mediators CRP, IL-6 and ferritin, and their relations to aging in general and Type 2 diabetes in particular. In addition, underlying mechanisms - including those related to gut microbiota and the receptors for AGEs, and the roles AGEs might play in affecting physiologies of the healthy elderly, obese individuals, and diabetics are discussed in regard to any greater susceptibility to COVID-19.

Effects of probiotics, prebiotics, and synbiotics on polycystic ovary syndrome: a systematic review and meta-analysis

This meta-analysis of randomized controlled trials (RCTs) was performed to summarize the effects of probiotics, prebiotics, and synbiotics on insulin resistance (IR), lipid profiles, anthropometric indices, and C-reactive protein (CRP) level for polycystic ovary syndrome (PCOS). We searched 8 databases from their inception until 1st October, 2020. The effect sizes were expressed as standardized mean difference (SMD) with 95% confidence intervals (95% CI). Subgroup analyses were undertaken for further identification of effects of probiotics, prebiotics, and synbiotics, based on the following aspects: (1) type of intervention (probiotics, prebiotics, or synbiotics); (2) study duration (≥ 12 weeks or < 12 weeks); (3) number of probiotic strains (multi strains or single strain); (4) probiotic dose (≥ 2 × 10⁸ colony-forming units [CFU] or < 2 × 10⁸ CFU). A total of 17 eligible RCTs with 1049 participants were included. Results showed that probiotic, prebiotic, and synbiotic intake decreased fasting plasma glucose (SMD, -1.35; 95% CI, -2.22 to -0.49; p = 0.002), fasting insulin (SMD, -0.68; 95% CI, -1.08 to -0.27; p = 0.001), homeostatic model of assessment for IR (SMD, -0.73; 95% CI, -1.15 to -0.31; p = 0.001), triglycerides (SMD, -0.85; 95% CI, -1.59 to -0.11; p = 0.024), total cholesterol (SMD, -1.09; 95% CI, -1.98 to -0.21; p = 0.015), low-density lipoprotein cholesterol (SMD, -0.84; 95% CI, -1.64 to -0.03; p = 0.041), very-low-density lipoprotein cholesterol (SMD, -0.44; 95% CI, -0.70 to -0.18; p = 0.001), and increased quantitative insulin sensitivity check index (SMD, 2.00; 95% CI, - 0.79 to 3.22; p = 0.001). However, probiotic, prebiotic, and synbiotic supplements did not affect anthropometric indices, high-density lipoprotein cholesterol, and CRP levels. Subgroup analysis showed that probiotic or prebiotic might be the optimal choice for ameliorating IR or lipid profiles, respectively. Additionally, the effect was positively related to courses and therapeutical dose. Overall, the meta-analysis demonstrates that probiotic, prebiotic, or synbiotic administration is an effective and safe intervention for modifying IR and lipid profiles.

Interactions between the microbiota and enteric nervous system during gut-brain disorders

For the last 20 years, researchers have focused their intention on the impact of gut microbiota in healthy and pathological conditions. This year (2021), more than 25,000 articles can be retrieved from PubMed with the keywords "gut microbiota and physiology", showing the constant progress and impact of gut microbes in scientific life. As a result, numerous therapeutic perspectives have been proposed to modulate the gut microbiota composition and/or bioactive factors released from microbes to restore our body functions. Currently, the gut is considered a primary site for the development of pathologies that modify brain functions such as neurodegenerative (Parkinson's, Alzheimer's, etc.) and metabolic (type 2 diabetes, obesity, etc.) disorders. Deciphering the mode of interaction between microbiota and the brain is a real original option to prevent (and maybe treat in the future) the establishment of gut-brain pathologies. The objective of this review is to describe recent scientific elements that explore the communication between gut microbiota and the brain by focusing our interest on the enteric nervous system (ENS) as an intermediate partner. The ENS, which is known as the "second brain", could be under the direct or indirect influence of the gut microbiota and its released factors (short-chain fatty acids, neurotransmitters, gaseous factors, etc.). Thus, in addition to their actions on tissue (adipose tissue, liver, brain, etc.), microbes can have an impact on local ENS activity. This potential modification of ENS function has global repercussions in the whole body via the gut-brain axis and represents a new therapeutic strategy.

Multiomics Profiling Reveals Signatures of Dysmetabolism in Urban Populations in Central India

BACKGROUND

Non-communicable diseases (NCDs) have become a major cause of morbidity and mortality in India. Perturbation of host-microbiome interactions may be a key mechanism by which lifestyle-related risk factors such as tobacco use, alcohol consumption, and physical inactivity may influence metabolic health. There is an urgent need to identify relevant dysmetabolic traits for predicting risk of metabolic disorders, such as diabetes, among susceptible Asian Indians where NCDs are a growing epidemic.

METHODS

Here, we report the first in-depth phenotypic study in which we prospectively enrolled 218 adults from urban and rural areas of Central India and used multiomic profiling to identify relationships between microbial taxa and circulating biomarkers of cardiometabolic risk. Assays included fecal microbiota analysis by 16S ribosomal RNA gene amplicon sequencing, quantification of serum short chain fatty acids by gas chromatography-mass spectrometry, and multiplex assaying of serum diabetic proteins, cytokines, chemokines, and multi-isotype antibodies. Sera was also analysed for N-glycans and immunoglobulin G Fc N-glycopeptides.

RESULTS

Multiple hallmarks of dysmetabolism were identified in urbanites and young overweight adults, the majority of whom did not have a known diagnosis of diabetes. Association analyses revealed several host-microbe and metabolic associations.

CONCLUSIONS

Host-microbe and metabolic interactions are differentially shaped by body weight and geographic status in Central Indians. Further exploration of these links may help create a molecular-level map for estimating risk of developing metabolic disorders and designing early interventions.

Effect of Lactobacillus fermentum TKSN041 on improving streptozotocin-induced type 2 diabetes in rats

With the increasing incidence of type 2 diabetes, it is imperative to identify how to effectively prevent or treat this disease. Studies have shown that some lactic acid bacteria can improve type 2 diabetes with almost no side effects. Therefore, in this experimental study, we explored the preventive and therapeutic effects of Lactobacillus fermentum TKSN041 (L. fermentum TKSN041) on streptozotocin-induced type 2 diabetes in rats. The results showed that L. fermentum TKSN041 could reduce the amount of water intake, reduce weight loss, and control the increase in the fasting blood glucose level of diabetic rats. The organ index and tissue section results showed that L. fermentum TKSN041 could reduce the damage caused by diabetes to the liver, kidney, spleen, pancreatic, and brain tissue. Furthermore, L. fermentum TKSN041 decreased the levels of triglyceride (TG), total cholesterol (TC), low-density lipoprotein cholesterol (LDL), aminotransferase (AST), alanine aminotransferase (ALT), glycated serum proteins (GSP), malondialdehyde (MDA), interleukin 1 beta (IL-1β), interleukin 6 (IL-6), and endothelin 1 (ET-1) in serum and increased the serum levels of high-density lipoprotein cholesterol (HDL) and interleukin 10 (IL-10). Finally, L. fermentum TKSN041 up-regulated the mRNA and protein expressions of NF-kappa-B inhibitor-α (IκB-α), AMP-activated protein kinase (AMPK), insulin receptor substrate-1 (IRS-1), liver kinase B1 (LKB1), and glucose transporter 4 (GLUT4) and down-regulated those of nuclear factor-κBp65 (NFκB-p65) and tumor necrosis factor alpha (TNF-α). Furthermore, LF-TKSN041 up-regulated the mRNA expressions of peroxisome proliferator-activated receptor γ (PPAR-γ) and down-regulated neuropeptide Y (NPY), sterol regulatory element-binding protein-1 (SREBF-1), and vascular endothelial growth factor (VEGF). These results suggest that L. fermentum TKSN041 may be a useful intervention factor for the prevention or treatment of type 2 diabetes induced by STZ. Clinical trials are needed to further demonstrate its effectiveness.

Identification of Microbiota Biomarkers With Orthologous Gene Annotation for Type 2 Diabetes

Type 2 diabetes (T2D) is a systematic chronic metabolic condition with abnormal sugar metabolism dysfunction, and its complications are the most harmful to human beings and may be life-threatening after long-term durations. Considering the high incidence and severity at late stage, researchers have been focusing on the identification of specific biomarkers and potential drug targets for T2D at the genomic, epigenomic, and transcriptomic levels. Microbes participate in the pathogenesis of multiple metabolic diseases including diabetes. However, the related studies are still non-systematic and lack the functional exploration on identified microbes. To fill this gap between gut microbiome and diabetes study, we first introduced eggNOG database and KEGG ORTHOLOGY (KO) database for orthologous (protein/gene) annotation of microbiota. Two datasets with these annotations were employed, which were analyzed by multiple machine-learning models for identifying significant microbiota biomarkers of T2D. The powerful feature selection method, Max-Relevance and Min-Redundancy (mRMR), was first applied to the datasets, resulting in a feature list for each dataset. Then, the list was fed into the incremental feature selection (IFS), incorporating support vector machine (SVM) as the classification algorithm, to extract essential annotations and build efficient classifiers. This study not only revealed potential pathological factors for diabetes at the microbiome level but also provided us new candidates for drug development against diabetes.

Role of Postbiotics in Diabetes Mellitus: Current Knowledge and Future Perspectives

In the last decade, the gastrointestinal microbiota has been recognised as being essential for health. Indeed, several publications have documented the suitability of probiotics, prebiotics, and symbiotics in the management of different diseases such as diabetes mellitus (DM). Advances in laboratory techniques have allowed the identification and characterisation of new biologically active molecules, referred to as “postbiotics”. Postbiotics are defined as functional bioactive compounds obtained from food-grade microorganisms that confer health benefits when administered in adequate amounts. They include cell structures, secreted molecules or metabolic by-products, and inanimate microorganisms. This heterogeneous group of molecules presents a broad range of mechanisms and may exhibit some advantages over traditional “biotics” such as probiotics and prebiotics. Owing to the growing incidence of DM worldwide and the implications of the microbiota in the disease progression, postbiotics appear to be good candidates as novel therapeutic targets. In the present review, we summarise the current knowledge about postbiotic compounds and their potential application in diabetes management. Additionally, we envision future perspectives on this topic. In summary, the results indicate that postbiotics hold promise as a potential novel therapeutic strategy for DM.

Effects of probiotics on body adiposity and cardiovascular risk markers in individuals with overweight and obesity: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND & AIMS

Evidence suggests that gut microbiota is a potential factor in the pathophysiology of both obesity and related metabolic disorders. While individual randomized controlled trials (RCTs) have evaluated the effects of probiotics on adiposity and cardiovascular disease (CVD) risk factors in subjects with overweight and obesity, the results are inconsistent. Thus, this systematic review and meta-analysis aimed to evaluate the effects of probiotic supplementation on body weight, body adiposity and CVD risk markers in overweight and obese subjects.

METHODS

A systematic search for RCTs published up to December 2020 was conducted in MEDLINE (via PubMed), EMBASE, Scopus and LILACS. Meta-analysis using a random-effects model was chosen to analyze the impact of combined trials.

RESULTS

Twenty-six RCTs (n = 1720) were included. Data pooling showed a significant effect of probiotics in reducing body weight (MD:-0.70 kg; 95%CI:-1.04,-0.35 kg; P < 0.0001), body mass index (BMI) (MD:-0.24 kg/m²; 95%CI:-0.35,-0.12 kg/m²; P = 0.0001), waist circumference (WC) (MD:-1.13 cm; 95%CI:-1.54,-0.73 cm; P < 0.0001), fat mass (MD:-0.71 kg; 95%CI:-1.10,-0.32 kg; P = 0.0004), tumor necrosis factor-α (MD:-0.16 pg/ml; 95%CI:-0.24,-0.08 pg/ml; P = 0.0001), insulin (MD:-0.85mcU/ml; 95%CI:-1.50,-0.21mcU/ml; P = 0.010), total cholesterol (MD:-0.16 mmol/l; 95%CI:-0.26,-0.05 mmol/l; P = 0.003) and LDL (MD:-0.09 mmol/l; 95%CI:-0.16,-0.03 mmol/l; P = 0.006) compared with control groups. There was a significant decrease in body weight, BMI and WC in studies using both single and multi-bacterial species. Decreases in body adiposity parameters were only observed in studies using a probiotic dose of ≥ 10¹⁰ CFU and for ≥8 weeks duration.

CONCLUSIONS

The present meta-analysis suggests that probiotics consumption may be helpful for improving body weight, body adiposity and some CVD risk markers in individuals with overweight and obesity. The review was registered on PROSPERO (International prospective register of systematic reviews): CRD42020183136.

iNetModels 2.0: an interactive visualization and database of multi-omics data

It is essential to reveal the associations between various omics data for a comprehensive understanding of the altered biological process in human wellness and disease. To date, very few studies have focused on collecting and exhibiting multi-omics associations in a single database. Here, we present iNetModels, an interactive database and visualization platform of Multi-Omics Biological Networks (MOBNs). This platform describes the associations between the clinical chemistry, anthropometric parameters, plasma proteomics, plasma metabolomics, as well as metagenomics for oral and gut microbiome obtained from the same individuals. Moreover, iNetModels includes tissue- and cancer-specific Gene Co-expression Networks (GCNs) for exploring the connections between the specific genes. This platform allows the user to interactively explore a single feature's association with other omics data and customize its particular context (e.g. male/female specific). The users can also register their data for sharing and visualization of the MOBNs and GCNs. Moreover, iNetModels allows users who do not have a bioinformatics background to facilitate human wellness and disease research. iNetModels can be accessed freely at https://inetmodels.com without any limitation.

In Vitro Antidiabetic, Antioxidant Activity, and Probiotic Activities of Lactiplantibacillus plantarum and Lacticaseibacillus paracasei Strains

Diabetes, a chronic metabolic disorder, is characterized by persistent hyperglycemia. This study aimed to evaluate the hypoglycemic and antioxidant activities of lactic acid bacteria strains isolated from humans and food products and investigate the probiotic properties of the selected four strains. The hypoglycemic activity of the isolated strains was examined by evaluating the α-glucosidase and α-amylase inhibitory activities. The antioxidant activity was measured using the DPPH, ABTS, and FRAP assays. Four strains (Lactiplantibacillus plantarum MG4229, MG4296, MG5025, and Lacticaseibacillus paracasei MG5012) exhibited potent α-glucosidase inhibitory (>75%) and α-amylase inhibitory (>85%) activities, which were comparable to those of acarbose (>50%; 1000 μg/mL). Similarly, the radical scavenging and antioxidant activities of the four strains were comparable to those of ascorbic acid (50 μg/mL). Additionally, the probiotic properties of the four selected strains were examined based on acid and bile salt tolerance, auto-aggregation ability, and antibiotic resistance. The four strains were resistant to pH 2 (>50% of survivability) and 0.5% bile salt (>80% of survivability). Therefore, we suggest that the selected strains with hypoglycemic, antioxidant, probiotic properties can potentially prevent diabetes.

Targeting the gut to treat multiple sclerosis

The gut-brain axis (GBA) refers to the complex interactions between the gut microbiota and the nervous, immune, and endocrine systems, together linking brain and gut functions. Perturbations of the GBA have been reported in people with multiple sclerosis (pwMS), suggesting a possible role in disease pathogenesis and making it a potential therapeutic target. While research in the area is still in its infancy, a number of studies revealed that pwMS are more likely to exhibit altered microbiota, altered levels of short chain fatty acids and secondary bile products, and increased intestinal permeability. However, specific microbes and metabolites identified across studies and cohorts vary greatly. Small clinical and preclinical trials in pwMS and mouse models, in which microbial composition was manipulated through the use of antibiotics, fecal microbiota transplantation, and probiotic supplements, have provided promising outcomes in preventing CNS inflammation. However, results are not always consistent, and large-scale randomized controlled trials are lacking. Herein, we give an overview of how the GBA could contribute to MS pathogenesis, examine the different approaches tested to modulate the GBA, and discuss how they may impact neuroinflammation and demyelination in the CNS.

A new way for punicalagin to alleviate insulin resistance: regulating gut microbiota and autophagy

Background

Insulin resistance, defined as a diminished ability to respond to the stimulation of insulin, is the main line for a variety of metabolic-related diseases. Punicalagin (PU), a hydrolyzable tannin of pomegranate juice, exhibits multiple biological properties, including anti-oxidant, anti-cancer and anti-inflammatory activities.

Objective

This research study aimed at determining the protective effect of PU on insulin resistance and to uncover the underlying mechanism based on the gut microbiota, IKKβ/NF-κB pathway, and autophagy.

Design

An insulin resistance animal model was established using C57BL/6 mice fed with a high-fat diet (HFD) for 8 weeks. The model included two groups continuing a HFD for 12 weeks with or without administering via gavage with PU 20 mg/kg/day. Changes in fasting plasma glucose levels, fasting serum insulin levels, glucose and insulin tolerance, glycolipid metabolism, gut microbiota composition (16S rRNA gene sequencing), inflammatory responses, and autophagy in the liver were evaluated. Body weight gain, glycolipid metabolic disorder, liver injury, as well as systemic and hepatic insulin sensitivity, were significantly attenuated after supplementing with PU.

Results

This research study revealed that PU alleviated HFD-induced glucose and lipid disorders, liver injury and insulin resistance; decreased the Firmicutes/Bacteroides ratio, decreased the abundance of Coprococcus and Anaerotruncus, and increased Rikenellaceae; and decreased serum and liver tumor necrosis factor-alpha and interleukin-1β levels, inhibited liver IKKβ and NF-κB phosphorylation; and increased liver autophagy-related proteins LC3-II, P62, and Beclin1, and increased the number of liver autophagosomes.

Conclusion

PU can improve HFD-induced insulin resistance, improved liver glucose and lipid metabolism disorder and liver injury, and the potential mechanism is that PU inhibited the IKKβ/NF-κB inflammatory pathway by regulating gut microbiota homeostasis and up-regulating liver autophagy activity.

Bioactive Dietary Fibers Selectively Promote Gut Microbiota to Exert Antidiabetic Effects

High intake of dietary fibers was found to be inversely associated with type-2 diabetes (T2D), whereas the difference among different dietary fibers on T2D remains unclear. Therefore, we have investigated the effects of different dietary fibers on T2D. Nine types of dietary fibers were used to investigate and evaluate their effects on type-2 diabetic rats via physiology, genomics, and metabolomics. We found that supplementation with β-glucan, arabinogalactan, guar gum, apple pectin, glucomannan, and arabinoxylan significantly reduced the fasting blood glucose, whereas carrageenan, xylan, and xanthan gum did not affect glycemic control in diabetic rats. Also, bioactive dietary fibers (β-glucan, arabinogalactan, guar gum, and apple pectin) associated with the increased butyric acid level and abundance of beneficial bacteria (Lachnobacterium, Parabacteroides, Faecalibacterium, Akkermansia, and some butyric acid-producing bacteria), as well as improved host metabolism by decreasing 12α-hydroxylated bile acids, acylcarnitines, and amino acids (leucine, phenylalanine, citrulline, etc.), thereby exert beneficial effects on T2D. It was also found that β-glucan might attenuate insulin resistance via downregulation of Prevotella copri-mediated biosynthesis of branched-chain amino acids in T2D. Together, our study uncovered the effects of different dietary fibers on T2D, along with their potential mechanism.

The Role of Microbiota in Primary Sclerosing Cholangitis and Related Biliary Malignancies

Primary sclerosing cholangitis (PSC) is an immune-related cholangiopathy characterized by biliary inflammation, cholestasis, and multifocal bile duct strictures. It is associated with high rates of progression to end-stage liver disease as well as a significant risk of cholangiocarcinoma (CCA), gallbladder cancer, and colorectal carcinoma. Currently, no effective medical treatment with an impact on the overall survival is available, and liver transplantation is the only curative treatment option. Emerging evidence indicates that gut microbiota is associated with disease pathogenesis. Several studies analyzing fecal and mucosal samples demonstrate a distinct gut microbiome in individuals with PSC compared to healthy controls and individuals with inflammatory bowel disease (IBD) without PSC. Experimental mouse and observational human data suggest that a diverse set of microbial functions may be relevant, including microbial metabolites and bacterial processing of pharmacological agents, bile acids, or dietary compounds, altogether driving the intrahepatic inflammation. Despite critical progress in this field over the past years, further functional characterization of the role of the microbiota in PSC and related malignancies is needed. In this review, we discuss the available data on the role of the gut microbiome and elucidate important insights into underlying pathogenic mechanisms and possible microbe-altering interventions.

Polyphenol-Mediated Gut Microbiota Modulation: Toward Prebiotics and Further

The genome of gut microbes encodes a collection of enzymes whose metabolic functions contribute to the bioavailability and bioactivity of unabsorbed (poly)phenols. Datasets from high throughput sequencing, metabolome measurements, and other omics have expanded the understanding of the different modes of actions by which (poly)phenols modulate the microbiome conferring health benefits to the host. Progress have been made to identify direct prebiotic effects of (poly)phenols; albeit up to date, these compounds are not recognized as prebiotics sensu stricto. Interestingly, certain probiotics strains have an enzymatic repertoire, such as tannase, α-L-rhamnosidase, and phenolic acid reductase, involved in the transformation of different (poly)phenols into bioactive phenolic metabolites. In vivo studies have demonstrated that these (poly)phenol-transforming bacteria thrive when provided with phenolic substrates. However, other taxonomically distinct gut symbionts of which a phenolic-metabolizing activity has not been demonstrated are still significantly promoted by (poly)phenols. This is the case of Akkermansia muciniphila, a so-called antiobesity bacterium, which responds positively to (poly)phenols and may be partially responsible for the health benefits formerly attributed to these molecules. We surmise that (poly)phenols broad antimicrobial action free ecological niches occupied by competing bacteria, thereby allowing the bloom of beneficial gut bacteria. This review explores the capacity of (poly)phenols to promote beneficial gut bacteria through their direct and collaborative bacterial utilization and their inhibitory action on potential pathogenic species. We propose the term duplibiotic, to describe an unabsorbed substrate modulating the gut microbiota by both antimicrobial and prebiotic modes of action. (Poly)phenol duplibiotic effect could participate in blunting metabolic disturbance and gut dysbiosis, positioning these compounds as dietary strategies with therapeutic potential.

Effect of High-Fat Diet on the Intestinal Flora in Letrozole-Induced Polycystic Ovary Syndrome Rats

Aim

The aim of this study was to explore whether letrozole and high-fat diets (HFD) can induce obese insulin-resistant polycystic ovary syndrome (PCOS) with intestinal flora dysbiosis in a rat model. We compared the changes in the intestinal flora of letrozole-induced rats fed with HFD or normal chow, to explore the effects of HFD and letrozole independently and synergistically on the intestinal flora.

Methods

Five-week-old female Sprague Dawley (SD) rats were divided into four groups: control (C) group fed with regular diet; L1 group administered with letrozole and fed with regular diet; L2 group received letrozole and fed with HFD; and HFD group fed with HFD. At the end of the experiment, ovarian morphology, hormones, metabolism, oxidative stress, and inflammatory status of all rats were studied. 16S rDNA high-throughput sequencing was used to profile microbial communities, and various multivariate analysis approaches were used to quantitate microbial composition, abundance, and diversity.

Results

Compared to the C group, the increased plasma fasting insulin and glucose, HOMA-IR, triglyceride, testosterone, and malondialdehyde were significantly higher in the L2 group, while high-density lipoprotein cholesterol was significantly lower in the L1 group and L2 group. The indices of Chao1 and the Abundance-based Coverage Estimator (ACE) (α-diversity) in the L2 and HFD groups were significantly lower than that in the C group. Bray–Curtis dissimilarity based principal coordinate analysis (PCoA) plots and analysis of similarities (ANOSIM) test showed obvious separations between the L2 group and C group, between the HFD group and C group, and between the L2 and HFD groups. At the phylum level, Firmicutes and ratio of Firmicutes and Bacteroidetes (F/B ratio) were increased in the L2 group; Bacteroidetes was decreased in the L2 and HFD groups. No significant differences in bacterial abundance between the C group and L1 group were observed at the phylum level. Based on linear discriminant analysis (LDA) effect size (LEfSe) analysis, the bacterial genera (the relative abundance > 0.1%, LDA > 3, p < 0.05) were selected as candidate bacterial signatures. They showed that the abundance of Vibrio was significantly increased in the L1 group; Bacteroides and Phascolarctobacterium were enriched in the HFD group, and Bacteroides, Phascolarctobacterium, Blautia, Parabacteroides, Akkermansia [Ruminococcus]_torques_group, and Anaerotruncus were enriched in the L2 group.

Conclusion

The effect of letrozole on intestinal flora was not significant as HFD. HFD could destroy the balance of intestinal flora and aggravate the intestinal flora dysbiosis in PCOS. Letrozole-induced rats fed with HFD have many characteristics like human PCOS, including some metabolic disorders and intestinal flora dysbiosis. The dysbiosis was characterized by an increased Firmicutes/Bacteroidetes ratio, an expansion of Firmicutes, a contraction of Bacteroidetes, and the decreased microbial richness. Beta-diversity also showed significant differences in intestinal microflora, compared with control rats.

Inositols Depletion and Resistance: Principal Mechanisms and Therapeutic Strategies

Inositols are natural molecules involved in several biochemical and metabolic functions in different organs and tissues. The term "inositols" refers to five natural stereoisomers, among which myo-Inositol (myo-Ins) is the most abundant one. Several mechanisms contribute to regulate cellular and tissue homeostasis of myo-Ins levels, including its endogenous synthesis and catabolism, transmembrane transport, intestinal adsorption and renal excretion. Alterations in these mechanisms can lead to a reduction of inositols levels, exposing patient to several pathological conditions, such as Polycystic Ovary Syndrome (PCOS), hypothyroidism, hormonal and metabolic imbalances, like weight gain, hyperinsulinemia, dyslipidemia, and metabolic syndrome. Indeed, myo-Ins is involved in different physiological processes as a key player in signal pathways, including reproductive, hormonal, and metabolic modulation. Genetic mutations in genes codifying for proteins of myo-Ins synthesis and transport, competitive processes with structurally similar molecules, and the administration of specific drugs that cause a central depletion of myo-Ins as a therapeutic outcome, can lead to a reduction of inositols levels. A deeper knowledge of the main mechanisms involved in cellular inositols depletion may add new insights for developing tailored therapeutic approaches and shaping the dosages and the route of administration, with the aim to develop efficacious and safe approaches counteracting inositols depletion-induced pathological events.

Ethanol extract of Sargarsum fusiforme alleviates HFD/STZ-induced hyperglycemia in association with modulation of gut microbiota and intestinal metabolites in type 2 diabetic mice

Type 2 diabetes mellitus (T2DM) is considered a rapidly growing chronic disease that threatens human health worldwide. Extracts of various seaweeds have been shown to have anti-diabetic activity. Sargarsum fusiforme, an edible brown seaweed, has been shown to possess anti-inflammatory, anti-diabetic and anti-obesity activities. In this study, we investigated the beneficial effect of an ethanol extract of S. fusiforme (EE) on type 2 diabetes in mice induced with high-fat diet (HFD) and streptozotocin (STZ). Administering EE to the diabetic mice significantly reduced food intake, water intake and fasting blood glucose (FBG), while improving glucose tolerance, lipid profile and ameliorating hepatic oxidative stress. Furthermore, these animals also exhibited significantly diminished epididymal fat deposition, as well as less pathological changes in the heart and liver tissues, while displaying some highly enriched benign gut bacteria (e.g., Intestinimonas, Oscillibacter, Lachnoclostridium, unidentified_Lachnospiraceae, Roseburia and Anaerotruncus) and a lower abundance of bacteria associated with diabetes or other metabolic diseases (e.g., Enterorhabdus and Romboutsia). Metabolomic analysis revealed reduced levels of branched-chain amino acids (BCAA), such as l-valine and l-isoleucine, aromatic amino acids (AAA), such as l-tyrosine and l-phenylalanine, and increased levels of 4-hydroxyphenylacetic acid (4-HPA) in the gut content, suggesting that EE may impact T2DM through modulation of these compounds in the gut of the animals. Taken together, the results implied that S. fusiforme may contain valuable active components other than polysaccharides that have potential benefit in alleviating T2DM.

Oleuropein Ameliorates Advanced Stage of Type 2 Diabetes in db/db Mice by Regulating Gut Microbiota

Previous studies have reported the therapeutic effects of oleuropein (OP) consumption on the early stage of type 2 diabetes. However, the efficacy of OP on the advanced stage of type 2 diabetes has not been investigated, and the relationship between OP and intestinal flora has not been studied. Therefore, in this study, to explore the relieving effects of OP intake on the advanced stage of type 2 diabetes and the regulatory effects of OP on intestinal microbes, diabetic db/db mice (17-week-old) were treated with OP at the dose of 200 mg/kg for 15 weeks. We found that OP has a significant effect in decreasing fasting blood glucose levels, improving glucose tolerance, lowering the homeostasis model assessment–insulin resistance index, restoring histopathological features of tissues, and promoting hepatic protein kinase B activation in db/db mice. Notably, OP modulates gut microbiota at phylum level, increases the relative abundance of Verrucomicrobia and Deferribacteres, and decreases the relative abundance of Bacteroidetes. OP treatment increases the relative abundance of Akkermansia, as well as decreases the relative abundance of Prevotella, Odoribacter, Ruminococcus, and Parabacteroides at genus level. In conclusion, OP may ameliorate the advanced stage of type 2 diabetes through modulating the composition and function of gut microbiota. Our findings provide a promising therapeutic approach for the treatment of advanced stage type 2 diabetes.

Environmental Influences on the Human Microbiome and Implications for Noncommunicable Disease

The human microbiome contributes metabolic functions, protects against pathogens, educates the immune system, and through these basic functions, directly or indirectly, affects most of our physiologic functions. Here, we consider the human microbiome and its relationship to several major noncommunicable human conditions, including orodigestive tract cancers, neurologic diseases, diabetes, and obesity. We also highlight the scope of contextual macroenvironmental factors (toxicological and chemical environment, built environment, and socioeconomic environment) and individual microenvironmental factors (smoking, alcohol, and diet) that may push the microbiota toward less healthy or more healthy conditions, influencing the development of these diseases. Last, we highlight current uncertainties and challenges in the study of environmental influences on the human microbiome and implications for understanding noncommunicable disease, suggesting a research agenda to strengthen the scientific evidence base.

Blood-Glucose-Lowering Effect of Coptidis Rhizoma Extracts From Different Origins via Gut Microbiota Modulation in db/db Mice

Background:Coptidis rhizoma extracts (CREs) have been used widely for their anti-diabetic and anti-microbial activities, and berberine/jatrorrhizine/coptisine/palmatine are the primary bioactive components. Although guidelines have adopted content analyses of these components as a quality control method for CREs, it is difficult to differentiate the CREs from different sources using this method because of the lack of indications for their related pharmacological activities.

Purpose: To explore the effect of CREs (CREA/CREB/CREC) with different compositions of major components on the gut microbiota and blood glucose levels in db/db mice.

Methods: Degradation of berberine/jatrorrhizine/coptisine/palmatine from CREA/CREB/CREC in rat/mouse intestinal contents and their impact on nine common gastrointestinal bacteria were investigated. In addition, the effects of oral administration of CREA/CREB/CREC for 2 weeks on the gut microbiota and blood glucose levels in db/db mice were monitored via insulin/glucose tolerance test (ITT/GTT), insulin concentration, homeostatic model assessment of insulin resistance and fecal 16S rRNA sequencing.

Results and Conclusion: The total amount of berberine/jatrorrhizine/coptisine/palmatine was highest in CREA. Clostridium perfringens was strongly inhibited by all three CREs, with CREA demonstrating the most significant inhibitory effects on minimum inhibitory concentration, time-kill kinetics, and ATP production. In db/db mice, CREA resulted in the most significant decrease in ITT/GTT and depicted different changes in the microbiota from CREB/CREC. Thus, CREs with different compositions of berberine/jatrorrhizine/coptisine/palmatine differed in terms of time-kill kinetics and ATP production assays on C. perfringens. CREA revealed the potent bacterial inhibitory effects and glucose-lowering activity.

In Vitro Fecal Fermentation Patterns of Arabinoxylan from Rice Bran on Fecal Microbiota from Normal-Weight and Overweight/Obese Subjects

Arabinoxylan (AX) is a structural polysaccharide found in wheat, rice and other cereal grains. Diets high in AX-containing fiber may promote gut health in obesity through prebiotic function. Thus, the impact of soluble AX isolated from rice bran fiber on human gut microbiota phylogenetic composition and short-chain fatty acid (SCFA) production patterns from normal-weight and overweight/obese subjects was investigated through in vitro fecal fermentation. Results showed that rice bran arabinoxylan modified the microbiota in fecal samples from both weight classes compared to control, significantly increasing Collinsella, Blautia and Bifidobacterium, and decreasing Sutterella, Bilophila and Parabacteroides. Rice bran AX also significantly increased total and individual SCFA contents (p < 0.05). This study suggests that rice bran AX may beneficially impact gut health in obesity through prebiotic activities.

Ethanol extract of mulberry leaves partially restores the composition of intestinal microbiota and strengthens liver glycogen fragility in type 2 diabetic rats

BACKGROUND

Mulberry leaf as a traditional Chinese medicine is able to treat obesity, diabetes, and dyslipidemia. It is well known that diabetes leads to intestinal microbiota dysbiosis. It is also recently discovered that liver glycogen structure is impaired in diabetic animals. Since mulberry leaves are able to improve the diabetic conditions through reducing blood glucose level, it would be interesting to investigate whether they have any positive effects on intestinal microbiota and liver glycogen structure.

METHODS

In this study, we first determined the bioactive components of ethanol extract of mulberry leaves via high-performance liquid chromatography (HPLC) and liquid chromatography/mass spectrometry (LC/MS). Murine animal models were divided into three groups, normal Sprague-Dawley (SD) rats, high-fat diet (HFD) and streptozotocin (STZ) induced type 2 diabetic rats, and HFD/STZ-induced rats administered with ethanol extract of mulberry leaves (200 mg/kg/day). Composition of intestinal microbiota was analyzed via metagenomics by sequencing the V3-V4 region of 16S rDNAs. Liver glycogen structure was characterized through size exclusion chromatography (SEC). Both Student's t-test and Tukey's test were used for statistical analysis.

RESULTS

A group of type 2 diabetic rat models were successfully established. Intestinal microbiota analysis showed that ethanol extract of mulberry leaves could partially change intestinal microbiota back to normal conditions. In addition, liver glycogen was restored from fragile state to stable state through administration of ethanol extract of mulberry leaves.

CONCLUSIONS

This study confirms that the ethanol extract of mulberry leaves (MLE) ameliorates intestinal microbiota dysbiosis and strengthens liver glycogen fragility in diabetic rats. These finding can be helpful in discovering the novel therapeutic targets with the help of further investigations.

Gut microbiome composition and serum metabolome profile among individuals with spinal cord injury and normal glucose tolerance or prediabetes/type 2 diabetes

OBJECTIVE

To compare the gut microbiome composition and serum metabolome profile among individuals with spinal cord injury (SCI) and normal glucose tolerance (NGT) or prediabetes/type 2 diabetes (P/DM).

DESIGN

Cross-sectional design.

SETTING

Research university.

PARTICIPANTS

A total of 25 adults with SCI were included in the analysis and categorized as NGT (n=16) or P/DM (n=9) based on their glucose concentration at minute 120 during a 75-g oral glucose tolerance test. The American Diabetes Association diagnosis guideline was used for grouping participants.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURE(S)

A stool sample was collected and used to assess the gut microbiome composition (alpha and beta diversity, microbial abundance) via the 16s rRNA sequencing technique. A fasting serum sample was used for liquid chromatography-mass spectrometry-based untargeted metabolomics analysis, the results from which reflect the relative quantity of metabolites detected and identified. Gut microbiome and metabolomics data were analyzed by the Quantitative Insights into Microbial Ecology 2 and Metaboanalyst platforms, respectively.

RESULTS

Gut microbiome alpha diversity (Pielou's evenness index, Shannon's index) and beta diversity (weighted UniFrac distances) differed between groups. Compared with participants with NGT, participants with P/DM had less evenness in microbial communities. In particular, those with P/DM had a lower abundance of the Clostridiales order and higher abundance of the Akkermansia genus, as well as higher serum levels of gut-derived metabolites, including indoxyl sulfate and phenylacetylglutamine (P < 0.05 for all).

CONCLUSION(S)

Our results provide evidence for altered gut microbiome composition and dysregulation of gut-derived metabolites in participants with SCI and P/DM. Both indoxyl sulfate and phenylacetylglutamine have been implicated in the development of cardiovascular diseases in the able-bodied population. These findings may inform future investigations in the field of SCI and cardio-metabolic health.

The Effects of Limosilactobacillus reuteri LR-99 Supplementation on Body Mass Index, Social Communication, Fine Motor Function, and Gut Microbiome Composition in Individuals with Prader-Willi Syndrome: a Randomized Double-Blinded Placebo-Controlled Trial

Prader-Willi syndrome (PWS) is a rare genetic disorder associated with developmental delay, obesity, and neuropsychiatric comorbidities. Limosilactobacillus reuteri (Lactobacillus reuteri, Lact. reuteri) has demonstrated anti-obesity and anti-inflammatory effects in previous studies. In the present study, we aim to evaluate the effects of Lact. reuteri supplementation on body mass index (BMI), social behaviors, and gut microbiota in individuals with PWS. We conducted a 12-week, randomized, double-blind, placebo-controlled trial in 71 individuals with PWS aged 6 to 264 months (64.4 ± 51.0 months). Participants were randomly assigned to either receive daily Lact. reuteri LR-99 probiotic (6 × 10¹⁰ colony forming units) or a placebo sachet. Groupwise differences were assessed for BMI, ASQ-3, and GARS-3 at baseline, 6 weeks, and 12 weeks into treatment. Gut microbiome data was analyzed with the QIIME2 software package, and predictive functional profiling was conducted with PICRUSt-2. We found a significant reduction in BMI for the probiotic group at both 6 weeks and 12 weeks relative to the baseline (P < 0.05). Furthermore, we observed a significant improvement in social communication and interaction, fine motor function, and total ASQ-3 score in the probiotics group compared to the placebo group (P < 0.05). Altered gut microbiota was observed in the probiotic group to favor weight loss and improve gut health. The findings suggest a novel therapeutic potential for Lact. reuteri LR-99 probiotic to modulate BMI, social behaviors, and gut microbiota in Prader-Willi syndrome patients, although further investigation is warranted.Trial registration Chinese Clinical Trial Registry: ChiCTR1900022646.

Protective Effects of Almond Oil on Streptozotocin-Induced Diabetic Rats via Regulating Nrf2/HO-1 Pathway and Gut Microbiota

Almond oil has been used as a medicine substitution for its numerous health benefits. This study aimed to evaluate the effect of almond oil on streptozotocin- (STZ-) induced diabetic rats for 4 weeks. The results showed that the administration of almond oil could significantly increase body weight, attenuate abnormally elevated blood glucose, promote insulin secretion, and improve glucose tolerance. Almond oil treatment also suppressed oxidative stress, reduced inflammation reaction, improved liver and kidney function, upregulated the expressions of Nrf2, HO-1, and NQO1, while downregulating the expression of Keap1. Furthermore, almond oil reversed the gut microbiota change by STZ and regulated the gut microbiota associated with glucose metabolism. At the phylum level, the relative abundance of Firmicutes was decreased, while Bacteroidetes was increased by almond oil treatment. More importantly, the ratio of Firmicutes/Bacteroidetes was significantly increased. At the genus level, administration of almond oil increased the abundances of Lactobacillus, Bacteroides, and Lachnospiraceae_NK4A136_group, while decreased the abundances of Ruminococcaceae_UCG-014, Clostridium_sensu_stricto_1, and Fusicatenibacter. These results provided evidence for the regulating effect of almond oil on diabetic rats via the Nrf2/HO-1 pathway and gut microbiota.

Positive influence of gut microbiota on the effects of Korean red ginseng in metabolic syndrome: a randomized, double-blind, placebo-controlled clinical trial

Background

Ginseng, a traditional herbal medicine, has been used for thousands of years to treat various diseases including metabolic syndrome (MS). However, the underlying mechanism(s) of such beneficial actions of ginseng against MS is poorly understood. Emerging evidence indicates a close association of the host gut microbiota with MS. The present study was conducted to examine, whether the beneficial effects of Korean red ginseng (KRG) against MS could be influenced by gut microbial population and whether gut microbial profile could be considered a valuable biomarker for targeted treatment strategy for MS in compliance with the predictive, preventive, and personalized medicine (PPPM / 3PM).

Methods

This clinical study was a randomized, double-blind, placebo-controlled trial evaluating the effects of KRG treatment for 8 weeks on patients with MS. The anthropometric parameters, vital signs, metabolic biomarkers, and gut microbial composition through 16S rRNA gene sequencing were assessed at the baseline and endpoint. The impact of KRG was also evaluated after categorizing the subjects into responders and non-responders, as well as enterotypes 1 and 2 based on their gut microbial profile at the baseline.

Results

Fifty out of 60 subjects who meet the MS criteria completed the trial without showing adverse reactions. The KRG treatment caused a significant decrease in systolic blood pressure (SBP). Microbial analysis revealed a decrease in Firmicutes, Proteobacteria, and an increase in Bacteroidetes in response to KRG. In patient stratification analysis, the responders showing marked improvement in the serum levels of lipid metabolic biomarkers TC and LDL due to the KRG treatment exhibited higher population of both the family Lachnospiraceae and order Clostridiales compared to the non-responders. The homeostasis model assessment-insulin resistance (HOMA-IR) and insulin level were decreased in enterotype 1 (Bacteroides-abundant group) and increased in enterotype 2 (prevotella-abundant group) following the KRG treatment.

Conclusion

In this study, the effects of KRG on the glucose metabolism in MS patients were influenced by the relative abundances of gut microbial population and differed according to the individual enterotype. Therefore, the analysis of enterotype categories is considered to be helpful in predicting the effectiveness of KRG on glucose homeostasis of MS patients individually. This will further help to decide on the appropriate treatment strategy for MS, in compliance with the perspective of PPPM.