Involvement of gut microbiota in the development of low-grade inflammation and type 2 diabetes associated with obesity

Relationships of ABO and Rhesus blood groups with type 2 diabetes mellitus: a systematic review and meta-analysis

OBJECTIVES

The susceptibility to type 2 diabetes mellitus (T2DM) has been linked to blood type. We aimed to characterize the relationships of the ABO and Rhesus blood groups with T2DM.

METHODS

Literature searches were performed using the Medline, PubMed, Scopus, Cochrane, EMBASE, and Google Scholar databases to identify studies published up to 31 March 2022. The PRISMA guidelines were used for reporting. Pooled odds ratios (ORs) with 95% confidence intervals (CIs) were obtained using fixed-effects models.

RESULTS

Twenty-six studies of 6870 patients with T2DM and 11,879 controls were identified. Compared with the other ABO groups, people with blood type B were at higher risk of T2DM (OR: 1.30, 95% CI: 1.20-1.41), while group O was associated with a lower risk (OR: 0.92, 95% CI: 0.86-0.98). There were no significant associations of T2DM with blood types A or AB, or Rh factor.

CONCLUSION

Individuals with blood type B are at higher risk of developing T2DM. Therefore, they should be screened for T2DM on a frequent basis and be made aware of the importance of maintaining a balanced diet and regular exercise for the prevention of obesity and T2DM.

PROSPERO REGISTRATION NUMBER

CRD42022353945.

Addition of Soluble Fiber in Low-Fat Purified Diets Maintains Cecal and Colonic Morphology, Modulates Bacterial Populations and Predicted Functions, and Improves Glucose Tolerance Compared with Traditional AIN Diets in Male Mice

Background

Purified diets (PDs) contain refined ingredients with one main nutrient, allowing for greater control relative to grain-based diets (GBDs), which contain unrefined grains and animal byproducts. Traditional PDs like the American Institute of Nutrition (AIN)-76A (76A) and AIN-93G (93G) can negatively impact metabolic and gut health when fed long term, in part due to lower total fiber, no soluble fiber, and higher sucrose content.

Objective

Two studies were conducted to determine how PDs with reduced sucrose and increased fiber (soluble and insoluble) influence metabolic and gut health in mice compared with traditional AIN PDs or GBDs.

Methods

In study 1, C57Bl/6N mice (n = 75) consumed a GBD [LabDiet 5002 (5002)], 76A, 93G, or 2 PDs with reduced sucrose and higher fiber for 88 d. Body composition and metabolic parameters were assessed. In study 2, C57Bl/6N mice (n = 54) consumed either 2 GBDs (LabDiet 5001 or 5002) or PDs with different types/levels of fiber for 14 d. Microbiome alterations and predicted functional metagenomic changes were measured.

Results

The PD with 75 g cellulose and 25 g inulin per 4084 kcals marginally influenced body weight and adiposity, but improved glucose tolerance relative to 93G (P = 0.0131) and 76A (P = 0.0014). Cecal and colonic weights were lower in mice fed cellulose-based PDs compared with those fed GBDs and soluble-fiber PDs. Soluble-fiber PDs reduced alpha diversity and showed similar beta diversity, which differed from cellulose-based PDs and GBDs. Certain genera associated with improved gut health such as Bifidobacteria and Akkermansia were significantly elevated by soluble-fiber PDs (P ≤ 0.01). Metabolic pathways related to carbohydrate and fatty acid metabolism were affected by PDs.

Conclusions

PDs formulated with lower sucrose and increased fiber content, particularly soluble fiber, blunted elevations in metabolic parameters and favorably impacted the microbiota and metagenome in C57BL/6N mice.

High fat diet-induced hyperlipidemia and tissue steatosis in rabbits through modulating ileal microbiota

High-fat diet (HFD) and overnutrition are important starting factors that may alter intestinal microbiota, lipid metabolism, and systemic inflammation. However, there were few studies on how intestinal microbiota contributes to tissue steatosis and hyperlipidemia. Here, we investigated the effect of lipid metabolism disorder-induced inflammation via toll-like receptor 2 (TLR-2), toll-like receptor 4 (TLR-4), and nuclear factor-κB (NF-κB) pathways at the intestinal level in response to HFD. Twenty 80-day-old male New Zealand White rabbits were randomly divided into the normal diet group (NDG) and the high-fat diet group (HDG) for 80 days. Growth performance, blood biochemical parameters, lipid metabolism, inflammation, degree of tissue steatosis, and intestinal microbial composition were measured. HFD increased the relative abundance of Christensenellaceae_R_7_group, Marvinbryantia, Akkermansia etc., with a reduced relative abundance of Enterorhabdus and Lactobacillus. Moreover, HFD caused steatosis in the liver and abdominal fat and abnormal expression of some genes related to lipid metabolism and tight junction proteins. The TLR-2, TLR-4, NF-κB, TNF-α, and IL-6 were confirmed by overexpression with downregulation of IL-10. Serum biochemical indices (TG, TCHO, LDL-C, and HDL-C) were also increased, indicating evidence for the development of the hyperlipidemia model. Correlation analysis showed that this microbial dysbiosis was correlated with lipid metabolism and inflammation, which were associated with the intestinal tract's barrier function and hyperlipidemia. These results provide an insight into the relationship between HFD, the intestinal microbiota, intestinal barrier, tissue inflammation, lipid metabolism, and hyperlipidemia. KEY POINTS: • High-fat diet leads to ileal microbiota disorders • Ileal microbiota mediates local and systemic lipid metabolism disorders and inflammation • There is a specific link between ileal microbiota, histopathology, and hyperlipidemia.

Effects of probiotic and magnesium co-supplementation on mood, cognition, intestinal barrier function and inflammation in individuals with obesity and depressed mood: A randomized, double-blind placebo-controlled clinical trial

Background

The co-occurrence of obesity and mood impairments named as “metabolic mood syndrome” (MMS) is often neglected in the obesity management. This study aimed to evaluate effects of Probio-Tec ^®BG-VCap-6.5 and magnesium co-supplementation on mood, cognition, intestinal barrier function and serum C reactive protein (CRP) levels in participants with obesity and depressed mood.

Design

Seventy-four eligible participants were randomly allocated to either Probio-Tec^®BG-VCap-6.5 [containing Lactobacillus rhamnosus (LGG^®) and Bifidobacterium animalis subsp. Lactis (BB-12^®)] + Magnesium chloride or placebo for 9 weeks. Sociodemographic data were collected in the beginning. Anthropometric, dietary and physical activity (PA) assessments were carried out. Beck Depression Inventory-II (BDI-II) and Montreal Cognitive Assessment (MoCA) scores were assessed through validated questionnaires. Fasting plasma zonulin, lipopolysaccharide (LPS) and (CRP) were measured by ELIZA kits.

Results

Of seventy-four participants (mean age 37.51 ± 8.10), 52 completed the study. Changes in serum LPS and zonulin were not different significantly between groups (−3.04 ± 44.75 ng/dl, 0.11 ± 5.13, ng/dl, p > 0.05 for LPS and 1.40 ± 48.78 ng/dl, −0.17 ± 6.60, p > 0.05 for zonulin, respectively). CRP levels reduced significantly in intervention group compared to placebo [−474.75 (−1,300.00, −125.00) mg/l vs. 175.20 (−957.75, 1,683.25) mg/l, p = 0.016]. Changes in BDI-II and MoCA scores were not significantly different between intervention (−7.13 ± 5.67, 1.20 ± 2.16, respectively) and placebo (−5.42 ± 6.71, 1.94 ± 1.86, respectively) groups (p > 0.05).

Conclusion

Nine weeks of probiotic and magnesium co-supplementation resulted in decreased CRP levels as an indicator of inflammatory state with no significant effects on mood, cognition and intestinal integrity in individuals with obesity and depressed mood.

Regulatory Effect of Isomaltodextrin on a High-Fat Diet Mouse Model with LPS-Induced Low-Grade Chronic Inflammation

This study aimed to identify the effects of isomaltodextrin (IMD) on sustaining the gut integrity and microbiota composition in a high-fat diet (HFD) with a lipopolysaccharide (LPS)-induced low-grade inflammation mouse model. The homeostasis of the immune response is important to reduce the risk of developing metabolic syndromes. The results of this study showed that pre-treatment of IMD at 5% (w/v) suppressed the concentration of endotoxin and pro-inflammatory mediators TNF-α, MCP-1, and IL-6 while increasing the adiponectin level in the plasma. Subsequently, IMD supplementation maintained the structural integrity and intestinal permeability by upregulating the tight junction protein expressions, leading to reducing D-mannitol concentration in the blood. In addition, dysbiosis was observed in mice induced by HFD plus LPS, suggesting that unhealthy dietary factors elicit metabolic endotoxemia and associated dysbiosis to impair the barrier function. However, IMD supplementation was shown to restore the microbial diversity, promote the growth of Bacteroides-Prevotella, and upregulate the related d-glucarate and d-galactarate degradation pathways, together demonstrating the benefits of IMD as a prebiotic able to promote energy homeostasis. Our results also showed that the blood lipid profile and glucose level in the low-grade inflammation mouse model were modulated by IMD. Moreover, IMD supplementation effectively prevented the metabolic disorder and modulated immune responses in inflamed white adipose tissues by inhibiting the macrophage infiltration and restoring the adiponectin, PPAR-γ, and IRS-1 expression. These findings provide strong evidence for IMD to be a potential prebiotic that acts to sustain a healthy gut microbiota composition and barrier function. By protecting against an unhealthy diet-impaired metabolic balance and maintaining immune homeostasis, IMD may affect the development of metabolic disorders.

Diet, microbiota, and the mucus layer: The guardians of our health

The intestinal tract is an ecosystem in which the resident microbiota lives in symbiosis with its host. This symbiotic relationship is key to maintaining overall health, with dietary habits of the host representing one of the main external factors shaping the microbiome-host relationship. Diets high in fiber and low in fat and sugars, as opposed to Western and high-fat diets, have been shown to have a beneficial effect on intestinal health by promoting the growth of beneficial bacteria, improve mucus barrier function and immune tolerance, while inhibiting pro-inflammatory responses and their downstream effects. On the contrary, diets low in fiber and high in fat and sugars have been associated with alterations in microbiota composition/functionality and the subsequent development of chronic diseases such as food allergies, inflammatory bowel disease, and metabolic disease. In this review, we provided an updated overview of the current understanding of the connection between diet, microbiota, and health, with a special focus on the role of Western and high-fat diets in shaping intestinal homeostasis by modulating the gut microbiota.

Pesticide thiram exposure alters the gut microbial diversity of chickens

Thiram is a major dithiocarbamate pesticide commonly found in polluted field crops, feed, and rivers. Environmental thiram exposure has been demonstrated to cause angiogenesis and osteogenesis disorders in chickens, but information regarding thiram influences on gut microbiota, apoptosis, and autophagy in chickens has been insufficient. Here, we explored the effect of thiram exposure on gut microbiota, apoptosis, and autophagy of chickens. Results demonstrated that thiram exposure impaired the morphology and structure of intestinal and liver tissues. Moreover, thiram exposure also triggered liver apoptosis and autophagy. The gut microbiota in chickens exposed to thiram exhibited a significant decline in alpha diversity, accompanied by significant shifts in taxonomic compositions. Bacterial taxonomic analysis indicated that thiram exposure causes a significant reduction in the levels of eight genera, as well as a significant increase in the levels of two phyla and 10 genera. Among decreased bacterial genera, seven genera even cannot be observed in the thiram-induced chickens. In summary, this study demonstrated that thiram exposure not only dramatically altered the gut microbial diversity and composition but also induced liver apoptosis and autophagy in chickens. Importantly, this study also conveyed a key message that the dysbiosis of gut microbiota may be one of the major pathways for thiram to exert its toxic effects.

ROLE OF GUT MICROBIOTA IN DEPRESSION: UNDERSTANDING MOLECULAR PATHWAYS, RECENT RESEARCH, AND FUTURE DIRECTION

Gut microbiota, also known as the "second brain" in humans because of the regulatory role it has on the central nervous system via neuronal, chemical and immune pathways. It has been proven that there exists a bidirectional communication between the gut and the brain. Increasing evidence supports that this crosstalk is linked to the etiology and treatment of depression. Reports suggest that the gut microbiota control the host epigenetic machinery in depression and gut dysbiosis causes negative epigenetic modifications via mechanisms like histone acetylation, DNA methylation and non-coding RNA mediated gene inhibition. The gut microbiome can be a promising approach for the management of depression. The diet and dietary metabolites like kynurenine, tryptophan, and propionic acid also greatly influence the microbiome composition and thereby, the physiological activities. This review gives a bird-eye view on the pathological updates and currently used treatment approaches targeting the gut microbiota in depression.

Orally administered Odoribacter laneus improves glucose control and inflammatory profile in obese mice by depleting circulating succinate

BACKGROUND

Succinate is produced by both human cells and by gut bacteria and couples metabolism to inflammation as an extracellular signaling transducer. Circulating succinate is elevated in patients with obesity and type 2 diabetes and is linked to numerous complications, yet no studies have specifically addressed the contribution of gut microbiota to systemic succinate or explored the consequences of reducing intestinal succinate levels in this setting.

RESULTS

Using germ-free and microbiota-depleted mouse models, we show that the gut microbiota is a significant source of circulating succinate, which is elevated in obesity. We also show in vivo that therapeutic treatments with selected bacteria diminish the levels of circulating succinate in obese mice. Specifically, we demonstrate that Odoribacter laneus is a promising probiotic based on its ability to deplete succinate and improve glucose tolerance and the inflammatory profile in two independent models of obesity (db/db mice and diet-induced obese mice). Mechanistically, this is partly mediated by the succinate receptor 1. Supporting these preclinical findings, we demonstrate an inverse correlation between plasma and fecal levels of succinate in a cohort of patients with severe obesity. We also show that plasma succinate, which is associated with several components of metabolic syndrome including waist circumference, triglycerides, and uric acid, among others, is a primary determinant of insulin sensitivity evaluated by the euglycemic-hyperinsulinemic clamp.

CONCLUSIONS

Overall, our work uncovers O. laneus as a promising next-generation probiotic to deplete succinate and improve glucose tolerance and obesity-related inflammation. Video Abstract.

SGLT-2 inhibition by empagliflozin has no effect on experimental arterial thrombosis in a murine model of low-grade inflammation

AIMS

Low-grade inflammation couples dysmetabolic states to insulin resistance and atherosclerotic cardiovascular (CV) disease (ASCVD). Selective sodium-glucose co-transporter 2 (SGLT-2) inhibition by empagliflozin improves clinical outcomes in patients with ASCVD independently of its glucose lowering effects. Yet, its mechanism of action remains largely undetermined. Here, we aimed to test whether empagliflozin affects arterial thrombus formation in baseline (BSL) conditions or low-grade inflammatory states, a systemic milieu shared among patients with ASCVD.

METHODS AND RESULTS

Sixteen-week-old C57BL/6 mice were randomly assigned to acute administration of empagliflozin (25 mg/kg body weight) or vehicle, of which a subgroup was pre-treated biweekly over 4 weeks with super-low-dose lipopolysaccharide (LPS; 5 ng/kg body weight), before carotid thrombosis was induced by photochemical injury. The between-group difference in Doppler-flow probe detected time-to-occlusion remained within the predefined equivalence margin (Δ = |10.50|), irrespective of low-grade inflammation (95% confidence interval, -9.82 to 8.85 and -9.20 to 9.69), while glucose dropped by 1.64 and 4.84 mmoL/L, respectively. Ex vivo platelet aggregometry suggested similar activation status, corroborated by unchanged circulating platelet-factor 4 plasma levels. In concert, carotid PAI-1 expression and tissue factor (TF) activity remained unaltered upon SGLT-2 inhibition, and no difference in plasma d-dimer levels was detected, suggesting comparable coagulation cascade activation and fibrinolytic activity. In human aortic endothelial cells pre-treated with LPS, empagliflozin neither changed TF activity nor PAI-1 expression. Accordingly, among patients with established ASCVD or at high CV risk randomized to a daily dose of 10 mg empagliflozin signatures of thrombotic (i.e. TF) and fibrinolytic activity (i.e. PAI-1) remained unchanged, while plasma glucose declined significantly during 3 months of follow-up.

CONCLUSION

SGLT-2 inhibition by empagliflozin does not impact experimental arterial thrombus formation, neither under BSL conditions nor during sustained low-grade inflammation, and has no impact on proxies of thrombotic/fibrinolytic activity in patients with ASCVD. The beneficial pleiotropic effects of empagliflozin are likely independent of pathways mediating arterial thrombosis.

Changes in the Gut Microbiome and Pathologies in Pregnancy

Pregnancy is a special period in a woman's life when her organism undergoes multiple physiological changes so that the fetus has optimal conditions for growth and development. These include modifications in the composition of the microbiome that occur between the first and third trimesters of pregnancy. There is an increase in Akkermansia, Bifidobacterium, and Firmicutes, which have been associated with an increase in the need for energy storage. The growth in Proteobacteria and Actinobacteria levels has a protective effect on both the mother and the fetus via proinflammatory mechanisms. The aim of the study is to review the research on the relationship between the mother's intestinal microbiome and gestational pathologies. Changes in the maternal gut microbiome is probably one of the mechanisms that occurs in various pregnancy diseases such as preeclampsia, fetal growth restriction, gestational diabetes mellitus, excessive gestational weight gain, and premature birth. For this reason, it seems vital to pay attention to certain interventions that can benefit the affected patients both in the short term, by preventing complications during pregnancy, and in the long term, as one of the mechanisms occurring in various gestational diseases is dysbiosis of the maternal intestinal flora.

Role of an unclassified Lachnospiraceae in the pathogenesis of type 2 diabetes: a longitudinal study of the urine microbiome and metabolites

Recent investigations have revealed that the human microbiome plays an essential role in the occurrence of type 2 diabetes (T2D). However, despite the importance of understanding the involvement of the microbiota throughout the body in T2D, most studies have focused specifically on the intestinal microbiota. Extracellular vesicles (EVs) have been recently found to provide important evidence regarding the mechanisms of T2D pathogenesis, as they act as key messengers between intestinal microorganisms and the host. Herein, we explored microorganisms potentially associated with T2D by tracking changes in microbiota-derived EVs from patient urine samples collected three times over four years. Mendelian randomization analysis was conducted to evaluate the causal relationships among microbial organisms, metabolites, and clinical measurements to provide a comprehensive view of how microbiota can influence T2D. We also analyzed EV-derived metagenomic (N = 393), clinical (N = 5032), genomic (N = 8842), and metabolite (N = 574) data from a prospective longitudinal Korean community-based cohort. Our data revealed that GU174097_g, an unclassified Lachnospiraceae, was associated with T2D (β = −189.13; p = 0.00006), and it was associated with the ketone bodies acetoacetate and 3-hydroxybutyrate (r = −0.0938 and −0.0829, respectively; p = 0.0022 and 0.0069, respectively). Furthermore, a causal relationship was identified between acetoacetate and HbA1c levels (β = 0.0002; p = 0.0154). GU174097_g reduced ketone body levels, thus decreasing HbA1c levels and the risk of T2D. Taken together, our findings indicate that GU174097_g may lower the risk of T2D by reducing ketone body levels.

A microbe that may help protect against type II diabetes has been detected by examining extracellular vesicles (EVs), tiny membrane-wrapped packages secreted by human cells and by the bacteria making up the microbiome. Examining EVs allows researchers to sample microbial populations other than the intensively studied intestinal microbiome. Sungho Won, Seoul National University, and Geum-Sook Hwang, Korea Basic Science Institute, Seoul, and coworkers studied the microbial EVs in urine samples collected from South Korean subjects over four years. They identified a previously unclassified bacterial species in the family Lachnospiraceae that was associated with lower risk of developing type II diabetes. Further investigation showed that these bacteria may break down ketone bodies, metabolic byproducts that signal disrupted sugar metabolism leading to diabetes. These results contribute to understanding how the microbiome contributes to metabolic health and disease.

Benign regulation of the gut microbiota: The possible mechanism through which the beneficial effects of manual acupuncture on cognitive ability and intestinal mucosal barrier function occur in APP/PS1 mice

Background

Gut microbiota dysbiosis and intestinal barrier injury play vital roles in Alzheimer's disease (AD) onset and development. Our previous studies have demonstrated that manual acupuncture (MA) could improve the cognitive abilities of APP/PS1 mice. However, the effect of MA on the intestinal mucosal barrier and the gut microbiota mechanism through which this effect occurs remain to be clarified.

Methods

In the APP/PS1 manual acupuncture (Am) group, MA was applied in Baihui (GV20), Yintang (GV29), and Zusanli (ST36). Mice in the APP/PS1 antibiotic + manual acupuncture (Aa) group were treated with an antibiotic mixture and MA at the same time. Probiotics were delivered to the APP/PS1 probiotics (Ap) group. Alterations in spatial learning and memory, the gut microbiota, the intestinal barrier function, and the expression of glial fibrillary acidic protein (GFAP), lipopolysaccharide (LPS), and TNF-α were evaluated in each group.

Results

Compared with the C57BL/6 control (Cc) group, cognitive ability was significantly decreased, the gut microbiota structure was obviously disrupted, intestinal barrier integrity was drastically impaired, and the intestinal inflammatory response was enhanced in the APP/PS1 control (Ac) group (P < 0.01). These changes were reversed by MA and probiotics (P < 0.01 or P < 0.05), whereas antibiotics inhibited the benign regulation by MA (P < 0.01 or P < 0.05).

Conclusion

Manual acupuncture can benignly modulate gut microbiota dysbiosis, significantly reduce intestinal inflammation, and effectively alleviate the destruction of the intestinal mucosal barrier in APP/PS1 mice, and the effects are comparable to those of probiotics. The gut microbiota may play an important role in the improvement of the cognitive function and intestinal barrier function by MA.

SARS-CoV-2 Spike protein is not pro-inflammatory in human primary macrophages: endotoxin contamination and lack of protein glycosylation as possible confounders

INTRODUCTION

The inflammatory potential of SARS-CoV-2 Spike S1 (Spike) has never been tested in human primary macrophages (MΦ). Different recombinant Spikes might display different effects in vitro, according to protein length and glycosylation, and endotoxin (lipopolysaccharide, LPS) contamination.

OBJECTIVES

To assess (1) the effects of different Spikes on human primary MΦ inflammation; (2) whether LPS contamination of recombinant Spike is (con)cause in vitro of increased MΦ inflammation.

METHODS

Human primary MΦ were incubated in the presence/absence of several different Spikes (10 nM) or graded concentrations of LPS. Pro-inflammatory marker expression (qPCR and ELISA) and supernatant endotoxin contamination (LAL test) were the main readouts.

RESULTS

LPS-free, glycosylated Spike (the form expressed in infected humans) caused no inflammation in human primary MΦ. Two (out of five) Spikes were contaminated with endotoxins ≥ 3 EU/ml and triggered inflammation. A non-contaminated non-glycosylated Spike produced in E. coli induced MΦ inflammation.

CONCLUSIONS

Glycosylated Spike per se is not pro-inflammatory for human MΦ, a feature which may be crucial to evade the host innate immunity. In vitro studies with commercially available Spike should be conducted with excruciating attention to potential LPS contamination.

Reactive Oxygen Species/Reactive Nitrogen Species as Messengers in the Gut: Impact on Physiology and Metabolic Disorders

Significance: The role of reactive oxygen/nitrogen species as "friend" or "foe" messengers in the whole body is well characterized. Depending on the concentration in the tissue considered, these molecular actors exert beneficial or deleterious impacts leading to a pathological state, as observed in metabolic disorders such as type 2 diabetes and obesity. Recent Advances: Among the tissues impacted by oxidation and inflammation in this pathological state, the intestine is a site of dysfunction that can establish diabetic symptoms, such as alterations in the intestinal barrier, gut motility, microbiota composition, and gut/brain axis communication. In the intestine, reactive oxygen/nitrogen species (from the host and/or microbiota) are key factors that modulate the transition from physiological to pathological signaling. Critical Issues: Controlling the levels of intestinal reactive oxygen/nitrogen species is a complicated balance between positive and negative impacts that is in constant equilibrium. Here, we describe the synthesis and degradation of intestinal reactive oxygen/nitrogen species and their interactions with the host. The development of novel redox-based therapeutics that alter these processes could restore intestinal health in patients with metabolic disorders. Future Directions: Deciphering the mode of action of reactive oxygen/nitrogen species in the gut of obese/diabetic patients could result in a future therapeutic strategy that combines nutritional and pharmacological approaches. Consequently, preventive and curative treatments must take into account one of the first sites of oxidative and inflammatory dysfunctions in the body, that is, the intestine. Antioxid. Redox Signal. 37, 394-415.

Modulation of gut microbiota by bioactive compounds for prevention and management of type 2 diabetes

Type 2 diabetes mellitus (T2DM) is a chronic metabolic disorder characterized by hyperglycemia and insulin resistance. Gut microbiota (GM) are specific groups of microbes colonized in the gastrointestinal (GI) tract. They profoundly influence health, disease protection, and associated with metabolic activities, and play a vital role in the production of functional metabolites from dietary substances. Dysbiosis of GM has been linked to the onset of T2DM and can be altered to attain eubiosis by intervention with various nutritional bioactive compounds such as polyphenols, prebiotics, and probiotics. This review presents an overview of the evidence and underlying mechanisms by which bioactive compounds modulate the GM for the prevention and management of T2DM.

Sex, pain, and the microbiome: The relationship between baseline gut microbiota composition, gender and somatic pain in healthy individuals

BACKGROUND AND AIM

Relative to men, women present with pain conditions more commonly. Although consistent differences exist between men and women in terms of physiological pain sensitivity, the underlying mechanisms are incompletely understood and yet could inform the development of effective sex specific treatments for pain. The gut microbiota can modulate nervous system functioning, including pain signaling pathways. We hypothesized that the gut microbiota and critical components of the gut-brain axis might influence electrical pain thresholds. Further, we hypothesized that sex, menstrual cycle, and hormonal contraceptive use might account for inter-sex differences in pain perception.

METHODS

Healthy, non-obese males (N = 15) and females (N = 16), (nine of whom were using hormonal contraceptives), were recruited. Male subjects were invited to undergo testing once, whereas females were invited three times across the menstrual cycle, based on self-reported early follicular (EF), late follicular (LF), or mid-luteal (ML) phase. On test days, electrical stimulation on the right ankle was performed; salivary cortisol levels were measured in the morning; levels of lipopolysaccharide-binding protein (LBP), soluble CD14 (sCD14), pro-inflammatory cytokines were assessed in plasma, and microbiota composition and short-chain fatty acids (SCFAs) levels were determined in fecal samples.

RESULTS

We observed that the pain tolerance threshold/pain sensation threshold (PTT/PST) ratio was significantly lesser in women than men, but not PST or PTT alone. Further, hormonal contraceptive use was associated with increased LBP levels (LF & ML phase), whilst sCD14 levels or inflammatory cytokines were not affected. Interestingly, in women, hormonal contraceptive use was associated with an increase in the relative abundance of Erysipelatoclostridium, and the relative abundances of certain bacterial genera correlated positively with pain sensation thresholds (Prevotella and Megasphera) during the LF phase and cortisol awakening response (Anaerofustis) during the ML phase. In comparison with men, women displayed overall stronger associations between i) SCFAs data, ii) cortisol data, iii) inflammatory cytokines and PTT and PST.

DISCUSSION AND CONCLUSION

Our findings support the hypothesis that the gut microbiota may be one of the factors determining the physiological inter-sex differences in pain perception. Further research is needed to investigate the molecular mechanisms by which specific sex hormones and gut microbes modulate pain signaling pathways, but this study highlights the possibilities for innovative individual targeted therapies for pain management.

The potential mechanisms of Macrocystis pyrifera polysaccharides mitigating type 2 diabetes in rats

Our previous studies have proved that the anti-digestive polysaccharide from Macrocystis pyrifera possesses potential hypoglycemic and lipid-lowering activities; however, its potential mechanisms for improving diabetes have not been elucidated. The current study was aimed to determine the anti-diabetic effects and possible mechanisms of Macrocystis pyrifera polysaccharides (MPP) in diabetic rats. After 8-week MPP treatment, the serum profiles, gut bacteria composition and relative gene expressions of rats were determined. MPP administration effectively ameliorated the diabetic symptoms, dyslipidemia, liver and kidney damage, oxidative stress and chronic inflammation in diabetic rats. In addition, MPP treatment could also notably improve the microbial dysbiosis by increasing the beneficial bacteria and decreasing a bacterial pathogen in the diabetic rats. The RT-qPCR analysis indicated that MPP intervention significantly up-regulated the IRS/PI3K/AKT signaling pathway and down-regulated the relative expressions of glucose-6-phosphatase (G-6-Pase), phosphoenolpyruvate carboxykinase (PEPCK), acetyl-CoA carboxylase (ACC), hydroxymethylglutaryl CoA reductase (HMGCR) and sterol regulatory element binding protein 1c (SREBP-1c) in diabetic rats. These results demonstrated that MPP had the potential to be exploited as functional foods or pharmaceutical supplements for preventing and treating diabetes.

Hypoglycemic Effects of Lycium barbarum Polysaccharide in Type 2 Diabetes Mellitus Mice via Modulating Gut Microbiota

This study aims to explore the molecular mechanisms of Lycium barbarum polysaccharide (LBP) in alleviating type 2 diabetes through intestinal flora modulation. A high-fat diet (HFD) combined with streptozotocin (STZ) was applied to create a diabetic model. The results indicated that LBP effectively alleviated the symptoms of hyperglycemia, hyperlipidemia, and insulin resistance in diabetic mice. A high dosage of LBP exerted better hypoglycemic effects than low and medium dosages. In diabetic mice, LBP significantly boosted the activities of CAT, SOD, and GSH-Px and reduced inflammation. The analysis of 16S rDNA disclosed that LBP notably improved the composition of intestinal flora, increasing the relative abundance of Bacteroides, Ruminococcaceae_UCG-014, Intestinimonas, Mucispirillum, Ruminococcaceae_UCG-009 and decreasing the relative abundance of Allobaculum, Dubosiella, Romboutsia. LBP significantly improved the production of short-chain fatty acids (SCFAs) in diabetic mice, which corresponded to the increase in the beneficial genus. According to Spearman’s correlation analysis, Cetobacterium, Streptococcus, Ralstonia. Cetobacterium, Ruminiclostridium, and Bifidobacterium correlated positively with insulin, whereas Cetobacterium, Millionella, Clostridium_sensu_stricto_1, Streptococcus, and Ruminococcaceae_UCG_009 correlated negatively with HOMA-IR, HDL-C, ALT, AST, TC, and lipopolysaccharide (LPS). These findings suggested that the mentioned genus may be beneficial to diabetic mice’s hypoglycemia and hypolipidemia. The up-regulation of peptide YY (PYY), glucagon-like peptide-1 (GLP-1), and insulin were remarkably reversed by LBP in diabetic mice. The real-time PCR (RT-PCR) analysis illustrated that LBP distinctly regulated the glucose metabolism of diabetic mice by activating the IRS/PI3K/Akt signal pathway. These results indicated that LBP effectively alleviated the hyperglycemia and hyperlipidemia of diabetic mice by modulating intestinal flora.

Targeting the gut to prevent and counteract metabolic disorders and pathologies during aging

Impairment of gut function is one of the explanatory mechanisms of health status decline in elderly population. These impairments involve a decline in gut digestive physiology, metabolism and immune status, and associated to that, changes in composition and function of the microbiota it harbors. Continuous deteriorations are generally associated with the development of systemic dysregulations and ultimately pathologies that can worsen the initial health status of individuals. All these alterations observed at the gut level can then constitute a wide range of potential targets for development of nutritional strategies that can impact gut tissue or associated microbiota pattern. This can be key, in a preventive manner, to limit gut functionality decline, or in a curative way to help maintaining optimum nutrients bioavailability in a context on increased requirements, as frequently observed in pathological situations. The aim of this review is to give an overview on the alterations that can occur in the gut during aging and lead to the development of altered function in other tissues and organs, ultimately leading to the development of pathologies. Subsequently is discussed how nutritional strategies that target gut tissue and gut microbiota can help to avoid or delay the occurrence of aging-related pathologies.

Artificial Gastrointestinal Models for Nutraceuticals Research—Achievements and Challenges: A Practical Review

Imitating the human digestive system as closely as possible is the goal of modern science. The main reason is to find an alternative to expensive, risky and time-consuming clinical trials. Of particular interest are models that simulate the gut microbiome. This paper aims to characterize the human gut microbiome, highlight the importance of its contribution to disease, and present in vitro models that allow studying the microbiome outside the human body but under near-natural conditions. A review of studies using models SHIME, SIMGI, TIM-2, ECSIM, EnteroMix, and PolyfermS will provide an overview of the options available and the choice of a model that suits the researcher’s expectations with advantages and disadvantages.

Risk assessment with gut microbiome and metabolite markers in NAFLD development

A growing body of evidence suggests interplay between the gut microbiota and the pathogenesis of nonalcoholic fatty liver disease (NAFLD). However, the role of the gut microbiome in early detection of NAFLD is unclear. Prospective studies are necessary for identifying reliable, microbiome markers for early NAFLD. We evaluated 2487 individuals in a community-based cohort who were followed up 4.6 years after initial clinical examination and biospecimen sampling. Metagenomic and metabolomic characterizations using stool and serum samples taken at baseline were performed for 90 participants who progressed to NAFLD and 90 controls who remained NAFLD free at the follow-up visit. Cases and controls were matched for gender, age, body mass index (BMI) at baseline and follow-up, and 4-year BMI change. Machine learning models integrating baseline microbial signatures (14 features) correctly classified participants (auROCs of 0.72 to 0.80) based on their NAFLD status and liver fat accumulation at the 4-year follow up, outperforming other prognostic clinical models (auROCs of 0.58 to 0.60). We confirmed the biological relevance of the microbiome features by testing their diagnostic ability in four external NAFLD case-control cohorts examined by biopsy or magnetic resonance spectroscopy, from Asia, Europe, and the United States. Our findings raise the possibility of using gut microbiota for early clinical warning of NAFLD development.

Intermittent hypoxia is involved in gut microbial dysbiosis in type 2 diabetes mellitus and obstructive sleep apnea-hypopnea syndrome

BACKGROUND

Obstructive sleep apnea (OSA)-hypopnea syndrome (OSAHS) has been recognized as a comorbidity of type 2 diabetes mellitus (T2DM); more than half of T2DM patients suffer from OSAHS. Intermittent hypoxia (IH) plays an important role in metabolic diseases, such as obesity and OSAHS, through various mechanisms, including altering the gut microecological composition and function. Therefore, it is important to study the role of gut microbiota in T2DM patients with OSAHS, which has a high incidence and is prone to several complications.

AIM

To assess whether IH is involved in altering the fecal microbiome in T2DM patients with OSAHS.

METHODS

Seventy-eight participants were enrolled from Henan Province People’s Hospital and divided into healthy control (HC, n = 26), T2DM (n = 25), and T2DM + OSA (n = 27) groups based on their conditions. The fecal bacterial DNA of the research participants was extracted and subjected to 16S ribosomal RNA sequencing. The clinical indices, such as insulin resistance index, homocysteine (HCY) concentration, and the concentrations of inflammatory factors in the peripheral blood, were assessed and recorded.

RESULTS

Group T2DM + OSA had the highest apnea-hypopnea index (AHI) (2.3 vs 3.7 vs 13.7), oxygen desaturation index (0.65 vs 2.2 vs 9.1), HCY concentration (9.6 μmol/L vs 10.3 μmol/L vs 13.81 μmol/L) and C-reactive protein (CRP) concentrations (0.3 mg/L vs 1.43 mg/L vs 2.11 mg/L), and lowest mean oxygen saturation (97.05% vs 96.6% vs 94.7%) among the three groups. Twelve and fifteen key differences in amplicon sequence variants were identified when comparing group T2DM + OSA with groups T2DM and HC, respectively. We found progressively decreased levels of Faecalibacterium, Eubacterium, and Lachnospiraceae, and an increase in the level of Actinomyces, which strongly correlated with the HCY, CRP, fasting plasma glucose, and hemoglobin A1c concentrations, AHI, mean oxygen saturation, and insulin resistance index in group T2DM + OSA (P < 0.05).

CONCLUSION

For T2DM patients with OSAHS, IH may be involved in selective alterations of the gut microbiota, which may affect the pathophysiological development of T2DM and DM-related complications.

Overview of Nutraceuticals and Cardiometabolic Diseases following Socio-Economic Analysis

The importance of functional food and nutraceutical products to deal with cardiometabolic diseases (CMDs) and metabolic syndrome (MetS) has gained attention in the past few years. The aim of this narrative review is to highlight the potential and effectiveness of nutraceutical in the improvement of CMDs and MetS biomarkers, alongside their burden of disease and economic health expenditure. A science database search was conducted between May and June 2021. A total of 35 studies were included in this paper. We included male and female subjects, children, and adults, in good health or with cardiovascular or metabolic disease. CMDs and MetS have gradually become worldwide health problems, becoming two of the major causes of morbidity and mortality in western countries. The results indicate a positive link between daily consumption of nutraceutical products and an improvement in cardiometabolic and anthropometric biomarkers. In this paper we included a wide range of nutraceutical products. Most of them showed promising data, indicating that nutraceuticals could provide a new therapeutic treatment to reduce prevalence and pharmaceutical expenditures attributed to CMDs and MetS. Unfortunately, there is a huge vacuum of data on nutraceutical usage, savings, and burden reduction. Therefore, further clinical and pharmaco-economic research in the field is highly required.

Personalized Nutrition for Microbiota Correction and Metabolism Restore in Type 2 Diabetes Mellitus Patients

Type 2 diabetes is one of the most common noncommunicable diseases in the world. Recent studies suggest a link between type 2 diabetes and microbiota, as well as the ability to treat and prevent it using personalized approaches to nutrition. In this work, we conducted clinical studies on the effects of a personalized diet on 56 female patients. Biochemical, physical, and immunological parameters were measured by standard methods on days 1 and 18 of the experiment. Gut and oral microbiota studies were performed in dynamics on days 1, 7, 11, and 18 using real-time polymerase chain reaction. With the help of the developed information system, a personalized diet was developed for each participant of the experiment. In the group of patients following personalized diets a statistically significant decreasing levels of glucose, thymol test, creatinine, very low-density lipoprotein, urea, secretory IgA, and tumour necrosis factor-α, and improvement in all physical parameters were observed. There was a statistically significant increase in uric acid, sodium, and magnesium. Statistically significant changes in gut microbiota were observed in Enterococcus faecalis, Escherichia coli (lac+, lac-), Lactobacillus spp., and Candida spp. Such microorganisms of oral microbiota as E. faecalis, Lactobacillus spp., Pseudomonas aeruginosa, and Candida spp. demonstrated statistically significant changes. All these changes indicate an improvement in the patients' condition in the experimental group compared to the control group. Our algorithm used for the development of personalized diets for patients with diabetes type 2 demonstrated clinical efficacy of its implementation.

Effect of Probiotic Therapy on Hemodynamic Response Associated with Systemic Inflammatory Reaction and Antibiotic-Induced Dysbiosis in Chronic Experiments in Rats

The effect of probiotic therapy on the main hemodynamic parameters was studied in Wistar rats with modeled syndrome of systemic inflammatory response resulting from chemically induced colitis complicated by antibiotic-induced dysbiosis. Using a wireless telemetry monitoring system in round-the-clock mode, the mean systolic and diastolic BP, HR, and body temperature were measured over 27 days. In the group of animals receiving no probiotics, a significant decrease in feed consumption and body weight loss were observed. By the end of the experiment, BP in this group was lower by 12% and HR was higher by 10% than in the control. In animals treated with a mixture of probiotic strains Lactobacillus acidophilus and Bifidobacterium animalis subsp. lactis, all the studied parameters returned to the initial values. Thus, we demonstrated the possibility of using probiotic drugs for the treatment of acute systemic inflammatory process, which should be considered in the development of new treatment protocols in veterinary and medicine.

Oxidative stress in the pathophysiology of type 2 diabetes and related complications: Current therapeutics strategies and future perspectives

Type 2 diabetes (T2DM) is a persistent metabolic disorder rising rapidly worldwide. It is characterized by pancreatic insulin resistance and β-cell dysfunction. Hyperglycemia induced reactive oxygen species (ROS) production and oxidative stress are correlated with the pathogenesis and progression of this metabolic disease. To counteract the harmful effects of ROS, endogenous antioxidants of the body or exogenous antioxidants neutralise it and maintain bodily homeostasis. Under hyperglycemic conditions, the imbalance between the cellular antioxidant system and ROS production results in oxidative stress, which subsequently results in the development of diabetes. These ROS are produced in the endoplasmic reticulum, phagocytic cells and peroxisomes, with the mitochondrial electron transport chain (ETC) playing a pivotal role. The exacerbated ROS production can directly cause structural and functional modifications in proteins, lipids and nucleic acids. It also modulates several intracellular signaling pathways that lead to insulin resistance and impairment of β-cell function. In addition, the hyperglycemia-induced ROS production contributes to micro- and macro-vascular diabetic complications. Various in-vivo and in-vitro studies have demonstrated the anti-oxidative effects of natural products and their derived bioactive compounds. However, there is conflicting clinical evidence on the beneficial effects of these antioxidant therapies in diabetes prevention. This review article focused on the multifaceted role of oxidative stress caused by ROS overproduction in diabetes and related complications and possible antioxidative therapeutic strategies targeting ROS in this disease.

Quercetin: an effective polyphenol in alleviating diabetes and diabetic complications

Various studies, especially in recent years, have shown that quercetin has beneficial therapeutic effects in various human diseases, including diabetes. Quercetin has significant anti-diabetic effects and may be helpful in lowering blood sugar and increasing insulin sensitivity. Quercetin appears to affect many factors and signaling pathways involved in insulin resistance and the pathogenesis of type 2 of diabetes. TNFα, NFKB, AMPK, AKT, and NRF2 are among the factors that are affected by quercetin. In addition, quercetin can be effective in preventing and ameliorating the diabetic complications, including diabetic nephropathy, cardiovascular complications, neuropathy, delayed wound healing, and retinopathy, and affects the key mechanisms involved in the pathogenesis of these complications. These positive effects of quercetin may be related to its anti-inflammatory and anti-oxidant properties. In this article, after a brief review of the pathogenesis of insulin resistance and type 2 diabetes, we will review the latest findings on the anti-diabetic effects of quercetin with a molecular perspective. Then we will review the effects of quercetin on the key mechanisms of pathogenesis of diabetes complications including nephropathy, cardiovascular complications, neuropathy, delayed wound healing, and retinopathy. Finally, clinical trials investigating the effect of quercetin on diabetes and diabetes complications will be reviewed.

The Effects of High Fiber Rye, Compared to Refined Wheat, on Gut Microbiota Composition, Plasma Short Chain Fatty Acids, and Implications for Weight Loss and Metabolic Risk Factors (the RyeWeight Study)

Consumption of whole grain and cereal fiber have been inversely associated with body weight and obesity measures in observational studies but data from large, long-term randomized interventions are scarce. Among the cereals, rye has the highest fiber content and high rye consumption has been linked to increased production of gut fermentation products, as well as reduced risks of obesity and metabolic disease. The effects on body weight and metabolic risk factors may partly be mediated through gut microbiota and/or their fermentation products. We used data from a randomized controlled weight loss trial where participants were randomized to a hypocaloric diet rich in either high fiber rye foods or refined wheat foods for 12 weeks to investigate the effects of the intervention on gut microbiota composition and plasma short chain fatty acids, as well as the potential association with weight loss and metabolic risk markers. Rye, compared to wheat, induced some changes in gut microbiota composition, including increased abundance of the butyrate producing Agathobacter and reduced abundance of [Ruminococcus] torques group, which may be related to reductions in low grade inflammation caused by the intervention. Plasma butyrate increased in the rye group. In conclusion, intervention with high fiber rye foods induced some changes in gut microbiota composition and plasma short chain fatty acid concentration, which were associated with improvements in metabolic risk markers as a result of the intervention.

Daily Inclusion of Resistant Starch-Containing Potatoes in a Dietary Guidelines for Americans Dietary Pattern Does Not Adversely Affect Cardiometabolic Risk or Intestinal Permeability in Adults with Metabolic Syndrome: A Randomized Controlled Trial

Poor diet quality influences cardiometabolic risk. Although potatoes are suggested to adversely affect cardiometabolic health, controlled trials that can establish causality are limited. Consistent with potatoes being rich in micronutrients and resistant starch, we hypothesized that their inclusion in a Dietary Guidelines for Americans (DGA)-based dietary pattern would improve cardiometabolic and gut health in metabolic syndrome (MetS) persons. In a randomized cross-over trial, MetS persons (n = 27; 32.5 ± 1.3 year) consumed a DGA-based diet for 2 weeks containing potatoes (DGA + POTATO; 17.5 g/day resistant starch) or bagels (DGA + BAGEL; 0 g/day resistant starch) prior to completing oral glucose and gut permeability tests. Blood pressure, fasting glucose and insulin, and insulin resistance decreased (p < 0.05) from baseline regardless of treatment without any change in body mass. Oral glucose-induced changes in brachial artery flow-mediated dilation, nitric oxide homeostasis, and lipid peroxidation did not differ between treatment arms. Serum endotoxin AUC0−120 min and urinary lactulose/mannitol, but not urinary sucralose/erythritol, were lower in DGA + POTATO. Fecal microbiome showed limited between-treatment differences, but the proportion of acetate was higher in DGA + POTATO. Thus, short-term consumption of a DGA-based diet decreases cardiometabolic risk, and the incorporation of resistant starch-containing potatoes into a healthy diet reduces small intestinal permeability and postprandial endotoxemia.

Pep19 Has a Positive Effect on Insulin Sensitivity and Ameliorates Both Hepatic and Adipose Tissue Phenotype of Diet-Induced Obese Mice

Peptide DIIADDEPLT (Pep19) has been previously suggested to improve metabolic parameters, without adverse central nervous system effects, in a murine model of diet-induced obesity. Here, we aimed to further evaluate whether Pep19 oral administration has anti-obesogenic effects, in a well-established high-fat diet-induced obesity model. Male Swiss mice, fed either a standard diet (SD) or high-fat diet (HFD), were orally administrated for 30 consecutive days, once a day, with saline vehicle or Pep19 (1 mg/kg). Next, several metabolic, morphological, and behavioral parameters were evaluated. Oral administration of Pep19 attenuated HFD body-weight gain, reduced in approximately 40% the absolute mass of the endocrine pancreas, and improved the relationship between circulating insulin and peripheral insulin sensitivity. Pep19 treatment of HFD-fed mice attenuated liver inflammation, hepatic fat distribution and accumulation, and lowered plasma alanine aminotransferase activity. The inguinal fat depot from the SD group treated with Pep19 showed multilocular brown-fat-like cells and increased mRNA expression of uncoupling protein 1 (UCP1), suggesting browning on inguinal white adipose cells. Morphological analysis of brown adipose tissue (BAT) from HFD mice showed the presence of larger white-like unilocular cells, compared to BAT from SD, Pep19-treated SD or HFD mice. Pep19 treatment produced no alterations in mice behavior. Oral administration of Pep19 ameliorates some metabolic traits altered by diet-induced obesity in a Swiss mice model.

Effect of Long-Term Hydroxytyrosol Administration on Body Weight, Fat Mass and Urine Metabolomics: A Randomized Double-Blind Prospective Human Study

Hydroxytyrosol (HT) is a natural antioxidant found in olive products and characterized by well-documented beneficial effects on human health. Several research studies are ongoing that aim to investigate its potency and molecular mechanism of action. The present study aimed to investigate the potential effect of HT on human obesity through a randomized double-blind prospective design. HT in two different doses (15 and 5 mg/day) and a placebo capsule was administered to 29 women with overweight/obesity for six months and their weight and fat mass were monitored at three time points (baseline, 4, 12 and 24 weeks). Statistically significant weight and visceral fat mass loss (%weight loss: p = 0.012, %visceral fat loss: p = 0.006) were observed in the group receiving the maximum HT dosage versus placebo after 4 weeks of the intervention, with attenuation of these findings at 12 and 24 weeks of the study. Urine samples were collected during the intervention and analyzed via liquid chromatography–high-resolution mass spectrometry for untargeted metabolomic purposes and comparisons between study groups were performed. HT administration was safe and well-tolerated. To the best of our knowledge, this is the first human cohort investigating the effects of HT on obesity for a prolonged study period.

Gut microbiota in gastrointestinal diseases during pregnancy

Gut microbiota (GM) is a micro-ecosystem composed of all microorganisms in the human intestine. The interaction between GM and the host plays an important role in maintaining normal physiological functions in the host. Dysbiosis of the GM may cause various diseases. GM has been demonstrated to be associated with human health and disease, and changes during individual development and disease. Pregnancy is a complicated physiological process. Hormones, the immune system, metabolism, and GM undergo drastic changes during pregnancy. Gastrointestinal diseases during pregnancy, such as hepatitis, intrahepatic cholestasis of pregnancy, and pre-eclampsia, can affect both maternal and fetal health. The dysregulation of GM during pregnancy may lead to a variety of diseases, including gastrointestinal diseases. Herein, we review recent research articles on GM in pregnancy-related gastrointestinal diseases, discuss the interaction of the GM with the host under normal physiological conditions, gastrointestinal diseases, and pregnancy-specific disorders. As more attention is paid to reproductive health, the pathogenic mechanism of GM in gastrointestinal diseases during pregnancy will be further studied to provide a theoretical basis for the use of probiotics to treat these diseases.

Effect of chronic restraint stress and western-diet feeding on colonic regulatory gene expression in mice

BACKGROUND

Diet-induced obesity (DIO) and psychological stress are significant independent regulators of gastrointestinal physiology; however, our understanding of how these two disorders influence the host-microbe interface is still poorly characterized. The aim of this study was to assess the combined influences of diet-induced obesity and psychological stress on microbiome composition and colonic gene expression.

METHODS

C57BL/6J mice (n = 48) were subject to a combination of 22 weeks of Western diet (WD) feeding and a chronic restraint stressor (CRS) for the last 4 weeks of feeding. At the end of the combined intervention, microbiome composition was determined from cecal contents, and colonic tissue gene expression was assessed by multiplex analysis using NanoString nCounter System and real-time qPCR.

RESULTS

WD feeding induced a DIO phenotype with increased body weight, worsened metabolic markers, and alterations to microbiome composition. CRS reduced body weight in both dietary groups while having differential effects on glucose metabolism. CRS improved the Firmicutes/Bacteroidetes ratio in WD-fed animals while expanding the Proteobacteria phyla. Significantly lower expression of colonic Tlr4 (p = 0.008), Ocln (p = 0.004), and Cldn3 (p = 0.004) were noted in WD-fed animals compared to controls with no synergistic effects observed when combined with CRS. No changes to colonic expression of downstream inflammatory mediators were observed. Interestingly, higher levels of expression of Cldn2 (p = 0.04) and bile acid receptor Nr1h4 (p = 0.02) were seen in mice exposed to CRS.

CONCLUSION

Differential but not synergistic effects of WD and CRS were noted at the host-microbe interface suggesting multifactorial responses that require further investigation.

Fecal Microbiota Transplant in a Pre-Clinical Model of Type 2 Diabetes Mellitus, Obesity and Diabetic Kidney Disease

Diabetes mellitus (DM) burden encompasses diabetic kidney disease (DKD), the leading cause of end-stage renal disease worldwide. Despite compelling evidence indicating that pharmacological intervention curtails DKD progression, the search for non-pharmacological strategies can identify novel targets for drug development against metabolic diseases. One of those emergent strategies comprises the modulation of the intestinal microbiota through fecal transplant from healthy donors. This study sought to investigate the benefits of fecal microbiota transplant (FMT) on functional and morphological parameters in a preclinical model of type 2 DM, obesity, and DKD using BTBR^ob/ob mice. These animals develop hyperglycemia and albuminuria in a time-dependent manner, mimicking DKD in humans. Our main findings unveiled that FMT prevented body weight gain, reduced albuminuria and tumor necrosis factor-α (TNF-α) levels within the ileum and ascending colon, and potentially ameliorated insulin resistance in BTBR^ob/ob mice. Intestinal structural integrity was maintained. Notably, FMT was associated with the abundance of the succinate-consuming Odoribacteraceae bacteria family throughout the intestine. Collectively, our data pointed out the safety and efficacy of FMT in a preclinical model of type 2 DM, obesity, and DKD. These findings provide a basis for translational research on intestinal microbiota modulation and testing its therapeutic potential combined with current treatment for DM.

Gut Microbiota: The Potential Key Target of TCM's Therapeutic Effect of Treating Different Diseases Using the Same Method-UC and T2DM as Examples

Traditional Chinese herbal medicine often exerts the therapeutic effect of "treating different diseases with the same method" in clinical practice; in other words, it is a kind of herbal medicine that can often treat two or even multiple diseases; however, the biological mechanism underlying its multi-path and multi-target pharmacological effects remains unclear. Growing evidence has demonstrated that gut microbiota dysbiosis plays a vital role in the occurrence and development of several diseases, and that the root cause of herbal medicine plays a therapeutic role in different diseases, a phenomenon potentially related to the improvement of the gut microbiota. We used local intestinal diseases, such as ulcerative colitis, and systemic diseases, such as type 2 diabetes, as examples; comprehensively searched databases, such as PubMed, Web of Science, and China National Knowledge Infrastructure; and summarized the related studies. The results indicate that multiple individual Chinese herbal medicines, such as Rhizoma coptidis (Huang Lian), Curcuma longa L (Jiang Huang), and Radix Scutellariae (Huang Qin), and Chinese medicinal compounds, such as Gegen Qinlian Decoction, Banxia Xiexin Decoction, and Shenling Baizhu Powder, potentially treat these two diseases by enriching the diversity of the gut microbiota, increasing beneficial bacteria and butyrate-producing bacteria, reducing pathogenic bacteria, improving the intestinal mucosal barrier, and inhibiting intestinal and systemic inflammation. In conclusion, this study found that a variety of traditional Chinese herbal medicines can simultaneously treat ulcerative colitis and type 2 diabetes, and the gut microbiota may be a significant target for herbal medicine as it exerts its therapeutic effect of "treating different diseases with the same method".

The Gut Microbiota Influenced by the Intake of Probiotics and Functional Foods with Prebiotics Can Sustain Wellness and Alleviate Certain Ailments like Gut-Inflammation and Colon-Cancer

The gut microbiota is composed of several microbial strains, with diverse and variable combinations in healthy and sick persons, changing at different stages of life. A healthy balance between host and gut microorganisms must be maintained in order to perform the normal physiological, metabolic, and immune functions and prevent disease development. Disturbances in the balance of the gut microbiota by diverse reasons initiate several health issues and promote the progression of certain diseases. This review is based on published research and reports that describe the role of probiotic microorganisms in the sustainability of health and the alleviation of certain diseases. Information is presented on the GRAS strains that are used as probiotics in the food industry for the production of fermented milk, yogurt, fermented food, functional foods, and probiotic drinks. To maintain a healthy microbiota, probiotic supplements in the form of freeze-dried live cells of probiotic strains are also available in different forms to consumers. The health benefits of lactic acid bacteria and other microorganisms and their role in the control of certain diseases such as gut inflammation, diabetes, and bowel cancer and in the safeguarding of the gut epithelial permeability from the invasion of pathogens are discussed.

Akkermansia muciniphila: from its critical role in human health to strategies for promoting its abundance in human gut microbiome

Akkermansia muciniphila, a frequent colonizer in the gut mucous layer of individuals, has constantly been recognized as a promising candidate for the next generation of probiotics due to its biological advantages from in vitro and in vivo investigations. This manuscript comprehensively reviewed the features of A. muciniphila in terms of its function in host physiology and frequently utilized nutrition using the published peer-reviewed articles, which should present valuable and critical information to scientists, engineers, and even the general population. A. muciniphila is an important bacterium that shows host physiology. However, its physiological advantages in several clinical settings also have excellent potential to become a probiotic. Consequently, it can be stated that there is a coherent and direct relation between the biological activities of the gut microbiota, intestinal dysbiosis/eubiosis, and the population of A. muciniphila in the gut milieu, which is influenced by various genetical and nutritional factors. Current regulatory barriers, the need for large-scale clinical trials, and the feasibility of production must be removed before A muciniphila can be extensively used as a next-generation probiotic.

Social overcrowding impacts gut microbiota, promoting stress, inflammation, and dysglycemia

An array of chronic inflammatory diseases, including metabolic diseases such as obesity and diabetes, are thought to be promoted by disturbance of the intestinal microbiota. Such diseases disproportionately impact low-income communities, which are frequently afflicted by chronic stress and increased density housing. Hence, we hypothesized that overcrowded housing might promote stress, microbiota dysbiosis, inflammation, and, consequently, metabolic diseases. We tested this hypothesis in a tractable murine model of social overcrowding (SOC), in which mice were housed at twice normal density. SOC moderately impacted behavior in some widely used assays (Open Field, Elevated Plus Maze and Light/Dark tests) and resulted in a stark increase in corticosterone levels. Such indices of stress were associated with mild chronic gut inflammation, hyperglycemia, elevations in colonic cytokines, and alterations in gut microbiota composition. All of these consequences of SOC were eliminated by broad spectrum antibiotics, while some (inflammation and hyperglycemia) were transmitted by microbiota transplantation from SOC mice to germfree mice housed at normal density. Altogether, these results suggest a central role for intestinal microbiota in driving stress, inflammation, and chronic diseases that are promoted by overcrowded housing.

Association of the Microbiota and Pancreatic Cancer: Opportunities and Limitations

The human body is thoroughly colonized by a wide variety of microorganisms, termed microbiota. Pancreatic cancer, one of the most aggressive forms of cancer, is no exception. The microbiota of pancreatic cancer largely influences and even dominates the occurrence, development and outcome of pancreatic cancer in many ways. Studies have shown that microbiota could change the malignant phenotype and prognosis of pancreatic cancer by stimulating persistent inflammation, regulating the antitumor immune system, changing the tumor microenvironment and affecting cellular metabolism. This is why the association of the microbiota with pancreatic cancer is an emerging area of research that warrants further exploration. Herein, we investigated the potential microbial markers of pancreatic cancer, related research models, the mechanism of action of microbiota in pancreatic cancer, and pancreatic cancer-microbiota-related treatment.

"More Guts Than Brains?"-The Role of Gut Microbiota in Idiopathic Intracranial Hypertension

BACKGROUND

Idiopathic intracranial hypertension syndrome (IIH) is most common among obese women. Weight loss is an important factor in improving papilledema. Over the last decade, growing evidence has identified gut microbiota as a potential factor in the pathophysiology of obesity. Accordingly, we investigated whether the gut microbiome is modified in IIH patients compared with healthy controls, and provide possible new treatment venues.

METHODS

Shotgun metagenomic sequencing of the gut microbiome of 25 cases of IIH patients (according to the modified Dandy criteria) and 20 healthy controls. Participants were further stratified according to their body mass index. The total DNA from each sample was extracted using the PureLink Microbiome DNA Purification Kit A29789 (Invitrogen, Thermo Fisher Scientific, US). Library preparation was performed using the Nextera DNA Flex Library Prep Kit. Samples were sequenced on the Illumina Novaseq 6000 device. A list of bacterial species that significantly differed between the IIH patients and healthy controls was produced in addition to species diversity. In addition, patients' cohort alone was analyzed, (excluding the healthy controls), and the effect of acetazolamide treatment on their gut microbiota was analyzed.

RESULTS

IIH patients have a lower diversity of bacterial species compared with healthy individuals. These bacteria, that is, Lactobacillus ruminis (L. ruminis) (p<6.95E-08), Atopobium parvulum (p<3.9E-03), Megamonas hypermegale (p<5.61E-03), Ruminococcus gnavus (p<1.29E-02), MEL.A1 (p<3.04E-02), and Streptococcus sp. I-G2 (p<3.04E-02), were previously characterized with beneficial health effects. Moreover, we found that Lactobacillus brevis, a beneficial bacterium as well, is more abundant in acetazolamide treated patients (p<7.07E-06).

CONCLUSIONS

Gut microbiota plays a potential role in IIH etiology and therefore, can provide a promising new treatment approach for this disease.

Insulin resistance per se drives early and reversible dysbiosis-mediated gut barrier impairment and bactericidal dysfunction

OBJECTIVE

A common feature of metabolic diseases is their association with chronic low-grade inflammation. While enhanced gut permeability and systemic bacterial endotoxin translocation have been suggested as key players of this metaflammation, the mechanistic bases underlying these features upon the diabesity cascade remain partly understood.

METHODS

Here, we show in mice that, independently of obesity, the induction of acute and global insulin resistance and associated hyperglycemia, upon treatment with an insulin receptor (IR) antagonist (S961), elicits gut hyperpermeability without triggering systemic inflammatory response.

RESULTS

Of note, S961-treated diabetic mice display major defects of gut barrier epithelial functions, such as increased epithelial paracellular permeability and impaired cell-cell junction integrity. We also observed in these mice the early onset of a severe gut dysbiosis, as characterized by the bloom of pro-inflammatory Proteobacteria, and the later collapse of Paneth cells antimicrobial defense. Interestingly, S961 treatment discontinuation is sufficient to promptly restore both the gut microbial balance and the intestinal barrier integrity. Moreover, fecal transplant approaches further confirm that S961-mediated dybiosis contributes at least partly to the disruption of the gut selective epithelial permeability upon diabetic states.

CONCLUSIONS

Together, our results highlight that insulin signaling is an indispensable gatekeeper of intestinal barrier integrity, acting as a safeguard against microbial imbalance and acute infections by enteropathogens.

Profiles of gut microbiota in obese-insulin-resistant rats treated with biotics

PURPOSE

Our previous studies demonstrated the beneficial effects of the probiotic Lactobacillus paracasei HII01, prebiotic xylooligosaccharide (XOS), and synbiotics on several parameters in high-fat diet (HFD)-induced obese rats. However, the gut microbiota composition in these rats has not been investigated. Therefore, this study aimed to investigate the impact of biotic therapies on gut microbiota in HFD-induced obese-insulin-resistant rats.

METHODS

Male Wistar rats were fed with a normal diet (ND, n = 5) and a HFD (n = 20) for 24 weeks. At week 13, HFD-fed rats were given either a probiotic (L. paracasei, HF-Pro, n = 5), prebiotic (XOS, HF-Pre, n = 5), synbiotic (XOS + L. paracasei, HF-Syn, n = 5), or vehicle (HF-V, n = 5) for 12 weeks. ND-fed rats received vehicle (ND-V, n = 5). At week 24, all rats were decapitated, and metabolic parameters and gut microbiota were analyzed.

RESULTS

HF-V rats developed an obese-insulin-resistant condition as indicated by impaired metabolic parameters. The prebiotic and synbiotic restored those metabolic parameters to the same level of ND-V rats. The gut microbiota composition of ND-V and HF-V rats differed as indicated by beta diversity. Verrucomicrobia in ND-V rats and Firmicutes and Proteobacteria in HF-V rats were dominant. Interestingly, Verrucomicrobia was also prominent in the HF-Syn rats. HF-Pre rats showed a distinct gut microbiota the predominant family being Ruminococcaceae.

CONCLUSION

The changes in gut microbiota after HFD consumption included increased Firmicutes and Proteobacteria. The treatment with the prebiotic and synbiotic showed an association with the increase in Ruminococcaceae and Verrucomicrobia, respectively. These changes in gut microbiota due to biotics may mediate the beneficial effects on metabolic parameters.

The Nutrition-Microbiota-Physical Activity Triad: An Inspiring New Concept for Health and Sports Performance

The human gut microbiota is currently the focus of converging interest in many diseases and sports performance. This review presents gut microbiota as a real “orchestra conductor” in the host’s physio(patho)logy due to its implications in many aspects of health and disease. Reciprocally, gut microbiota composition and activity are influenced by many different factors, such as diet and physical activity. Literature data have shown that macro- and micro-nutrients influence gut microbiota composition. Cumulative data indicate that gut bacteria are sensitive to modulation by physical activity, as shown by studies using training and hypoactivity models. Sports performance studies have also presented interesting and promising results. Therefore, gut microbiota could be considered a “pivotal” organ for health and sports performance, leading to a new concept: the nutrition-microbiota-physical activity triad. The next challenge for the scientific and medical communities is to test this concept in clinical studies. The long-term aim is to find the best combination of the three elements of this triad to optimize treatments, delay disease onset, or enhance sports performance. The many possibilities offered by biotic supplementation and training modalities open different avenues for future research.

Diabetes and Its Cardiovascular Complications: Comprehensive Network and Systematic Analyses

Diabetes mellitus is a worldwide health problem that usually comes with severe complications. There is no cure for diabetes yet and the threat of these complications is what keeps researchers investigating mechanisms and treatments for diabetes mellitus. Due to advancements in genomics, epigenomics, proteomics, and single-cell multiomics research, considerable progress has been made toward understanding the mechanisms of diabetes mellitus. In addition, investigation of the association between diabetes and other physiological systems revealed potentially novel pathways and targets involved in the initiation and progress of diabetes. This review focuses on current advancements in studying the mechanisms of diabetes by using genomic, epigenomic, proteomic, and single-cell multiomic analysis methods. It will also focus on recent findings pertaining to the relationship between diabetes and other biological processes, and new findings on the contribution of diabetes to several pathological conditions.

Diabetogenically beneficial gut microbiota alterations in third trimester of pregnancy

Altered gut microbiota (dysbiosis), inflammation and weight gain are pivotal to the success of normal pregnancy. These are features of metabolic syndrome that ordinarily increase the risk of type 2 diabetes in non-pregnant individuals. Though gut microbiota influences host energy metabolism and homeostasis, the outcome (healthy or unhealthy) varies depending on pregnancy status. In a healthy pregnancy, the gut microbiota is altered to promote metabolic and immunological changes beneficial to the mother and foetus but could connote a disease state in non-pregnant individuals. During the later stages of gestation, metabolic syndrome-like features, that is, obesity-related gut dysbiotic microbiota, increased insulin resistance, and elevated pro-inflammatory cytokines, promote energy storage in adipose tissue for rapid foetal growth and development, and in preparation for energy-consuming processes such as parturition and lactation. The origin of this gestation-associated host–microbial interaction is still elusive. Therefore, this review critically examined the host–microbial interactions in the gastrointestinal tract of pregnant women at late gestation (third trimester) that shift host metabolism in favour of a diabetogenic or metabolic syndrome-like phenotype. Whether the diabetogenic effects of such interactions are indeed beneficial to both mother and foetus was also discussed with plausible mechanistic pathways and associations highlighted.

Impact of antibiotics on the human microbiome and consequences for host health

It is well established that the gut microbiota plays an important role in host health and is perturbed by several factors including antibiotics. Antibiotic-induced changes in microbial composition can have a negative impact on host health including reduced microbial diversity, changes in functional attributes of the microbiota, formation, and selection of antibiotic-resistant strains making hosts more susceptible to infection with pathogens such as Clostridioides difficile. Antibiotic resistance is a global crisis and the increased use of antibiotics over time warrants investigation into its effects on microbiota and health. In this review, we discuss the adverse effects of antibiotics on the gut microbiota and thus host health, and suggest alternative approaches to antibiotic use.