Long term effect of gut microbiota transfer on diabetes development

Periodontal bacteria influence systemic diseases through the gut microbiota

Many systemic diseases, including Alzheimer disease (AD), diabetes mellitus (DM) and cardiovascular disease, are associated with microbiota dysbiosis. The oral and intestinal microbiota are directly connected anatomically, and communicate with each other through the oral-gut microbiome axis to establish and maintain host microbial homeostasis. In addition to directly, periodontal bacteria may also be indirectly involved in the regulation of systemic health and disease through the disturbed gut. This paper provides evidence for the role of periodontal bacteria in systemic diseases via the oral-gut axis and the far-reaching implications of maintaining periodontal health in reducing the risk of many intestinal and parenteral diseases. This may provide insight into the underlying pathogenesis of many systemic diseases and the search for new preventive and therapeutic strategies.

The predicted mechanisms and evidence of probiotics on type 2 diabetes mellitus (T2DM)

Type 2 diabetes mellitus (T2DM) is a serious endocrine and metabolic disease that is highly prevalent and causes high mortality and morbidity rates worldwide. This review aims to focus on the potential of probiotics in the management of T2DM and its complications and to summarise the various mechanisms of action of probiotics with respect to T2DM. In this review, experimental studies conducted between 2016 and 2022 were explored. The possible mechanisms of action are based on their ability to modulate the gut microbiota, boost the production of short-chain fatty acids (SCFAs) and glucagon-like peptides, inhibit α-glucosidase, elevate sirtuin 1 (SIRT1) levels while reducing fetuin-A levels, and regulate the level of inflammatory cytokines. This review recommends carrying out further studies, especially human trials, to provide robust evidence-based knowledge on the use of probiotics for the treatment of T2DM.IMPACT STATEMENTT2DM is prevalent worldwide causing high rates of morbidity and mortality.Gut microbiota play a significant role in the pathogenesis of T2DM.Probiotics can be used as possible therapeutic tools for the management of T2DM.The possible mechanisms of action of probiotics include modulation of the gut microbiota, production of SCFAs and glucagon-like peptides, inhibition of α-glucosidase, raising SIRT1, reducing fetuin-A levels, and regulating the level of inflammatory cytokines.

Predicting the role of the human gut microbiome in type 1 diabetes using machine-learning methods

Gut microbes is a crucial factor in the pathogenesis of type 1 diabetes (T1D). However, it is still unclear which gut microbiota are the key factors affecting T1D and their influence on the development and progression of the disease. To fill these knowledge gaps, we constructed a model to find biomarker from gut microbiota in patients with T1D. We first identified microbial markers using Linear discriminant analysis Effect Size (LEfSe) and random forest (RF) methods. Furthermore, by constructing co-occurrence networks for gut microbes in T1D, we aimed to reveal all gut microbial interactions as well as major beneficial and pathogenic bacteria in healthy populations and type 1 diabetic patients. Finally, PICRUST2 was used to predict Kyoto Encyclopedia of Genes and Genomes (KEGG) functional pathways and KO gene levels of microbial markers to investigate the biological role. Our study revealed that 21 identified microbial genera are important biomarker for T1D. Their AUC values are 0.962 and 0.745 on discovery set and validation set. Functional analysis showed that 10 microbial genera were significantly positively associated with D-arginine and D-ornithine metabolism, spliceosome in transcription, steroid hormone biosynthesis and glycosaminoglycan degradation. These genera were significantly negatively correlated with steroid biosynthesis, cyanoamino acid metabolism and drug metabolism. The other 11 genera displayed an inverse correlation. In summary, our research identified a comprehensive set of T1D gut biomarkers with universal applicability and have revealed the biological consequences of alterations in gut microbiota and their interplay. These findings offer significant prospects for individualized management and treatment of T1D.

Understanding Autoimmunity: Mechanisms, Predisposing Factors, and Cytokine Therapies

Autoimmunity refers to an organism's immune response against its own healthy cells, tissues, or components, potentially leading to irreversible damage to vital organs. Central and peripheral tolerance mechanisms play crucial roles in preventing autoimmunity by eliminating self-reactive T and B cells. The disruption of immunological tolerance, characterized by the failure of these mechanisms, results in the aberrant activation of autoreactive lymphocytes that target self-tissues, culminating in the pathogenesis of autoimmune disorders. Genetic predispositions, environmental exposures, and immunoregulatory disturbances synergistically contribute to the susceptibility and initiation of autoimmune pathologies. Within the realm of immune therapies for autoimmune diseases, cytokine therapies have emerged as a specialized strategy, targeting cytokine-mediated regulatory pathways to rectify immunological imbalances. Proinflammatory cytokines are key players in inducing and propagating autoimmune inflammation, highlighting the potential of cytokine therapies in managing autoimmune conditions. This review discusses the etiology of autoimmune diseases, current therapeutic approaches, and prospects for future drug design.

Dietary Patterns, Gut Microbiota and Sports Performance in Athletes: A Narrative Review

The intestinal tract of humans harbors a dynamic and complex bacterial community known as the gut microbiota, which plays a crucial role in regulating functions such as metabolism and immunity in the human body. Numerous studies conducted in recent decades have also highlighted the significant potential of the gut microbiota in promoting human health. It is widely recognized that training and nutrition strategies are pivotal factors that allow athletes to achieve optimal performance. Consequently, there has been an increasing focus on whether training and dietary patterns influence sports performance through their impact on the gut microbiota. In this review, we aim to present the concept and primary functions of the gut microbiota, explore the relationship between exercise and the gut microbiota, and specifically examine the popular dietary patterns associated with athletes' sports performance while considering their interaction with the gut microbiota. Finally, we discuss the potential mechanisms by which dietary patterns affect sports performance from a nutritional perspective, aiming to elucidate the intricate interplay among dietary patterns, the gut microbiota, and sports performance. We have found that the precise application of specific dietary patterns (ketogenic diet, plant-based diet, high-protein diet, Mediterranean diet, and high intake of carbohydrate) can improve vascular function and reduce the risk of illness in health promotion, etc., as well as promoting recovery and controlling weight with regard to improving sports performance, etc. In conclusion, although it can be inferred that certain aspects of an athlete's ability may benefit from specific dietary patterns mediated by the gut microbiota to some extent, further high-quality clinical studies are warranted to substantiate these claims and elucidate the underlying mechanisms.

Tlr9 deficiency in B cells leads to obesity by promoting inflammation and gut dysbiosis

Toll-like receptor 9 (TLR9) recognizes bacterial, viral and self DNA and play an important role in immunity and inflammation. However, the role of TLR9 in obesity is less well-studied. Here, we generate B-cell-specific Tlr9-deficient (Tlr9fl/fl/Cd19Cre+/-, KO) B6 mice and model obesity using a high-fat diet. Compared with control mice, B-cell-specific-Tlr9-deficient mice exhibited increased fat tissue inflammation, weight gain, and impaired glucose and insulin tolerance. Furthermore, the frequencies of IL-10-producing-B cells and marginal zone B cells were reduced, and those of follicular and germinal center B cells were increased. This was associated with increased frequencies of IFNγ-producing-T cells and increased follicular helper cells. In addition, gut microbiota from the KO mice induced a pro-inflammatory state leading to immunological and metabolic dysregulation when transferred to germ-free mice. Using 16 S rRNA gene sequencing, we identify altered gut microbial communities including reduced Lachnospiraceae, which may play a role in altered metabolism in KO mice. We identify an important network involving Tlr9, Irf4 and Il-10 interconnecting metabolic homeostasis, with the function of B and T cells, and gut microbiota in obesity.

Gestational diabetes-related gut microbiome dysbiosis is not influenced by different Asian ethnicities and dietary interventions: a pilot study

Gut microbiome dysbiosis contributes to the pathophysiology of both gestational diabetes mellitus (GDM) and its associated adverse outcomes in the woman and offspring. Even though GDM prevalence, complications, and outcomes vary among different ethnic groups, limited information is available about the influence of ethnicity on gut microbiome dysbiosis in pregnancies complicated by GDM. This pilot prospective cohort study examined the impact of ethnicity on gut dysbiosis in GDM among three Asian ethnic groups (Chinese, Malay, Indian) living in Singapore, and investigated the potential modulatory roles of diet and lifestyle modifications on gut microbiome post-GDM diagnosis. Women with GDM (n = 53) and without GDM (n = 16) were recruited. Fecal samples were collected at 24-28- and 36-40-weeks' gestation and analyzed by targeted 16S rRNA gene-based amplicon sequencing. Permutational multivariate analysis of variance (PERMANOVA) analysis was performed to evaluate differences between groups. Differentially abundant taxa were identified by DeSeq2 based analysis. Functional prediction was performed using the phylogenetic investigation of communities by reconstruction of unobserved states (PICRUSt2). Among women with GDM, gut microbiome from different ethnicities harbored common microbial features. However, among those without GDM, there was contrasting microbiome composition between ethnic groups. Microbial members such as Collinsella, Blautia, Ruminococcus, Ruminococcus gnavus, Ruminococcus torques, and Eubacterium hallii groups were differentially enriched (p < 0.05) in women with GDM compared to those without. Among women with GDM, no differences in alpha- and beta- diversity were observed when comparing 24-28 weeks' samples with 36-40 weeks' samples, a period covering intense dietary and lifestyle modification, suggesting an inability to modulate gut microbiota through classic GDM management. Women with GDM have a distinct gut microbiome profile which harbours common features across different Asian ethnic groups, consistent with the notion that specific microbes are involved in the pathogenesis of insulin resistance, pro-inflammatory conditions, and other metabolic dysregulation known to be present in GDM.

TLR5-deficiency controls dendritic cell subset development in an autoimmune diabetes-susceptible model

Introduction

The incidence of the autoimmune disease, type 1 diabetes (T1D), has been increasing worldwide and recent studies have shown that the gut microbiota are associated with modulating susceptibility to T1D. Toll-like receptor 5 (TLR5) recognizes bacterial flagellin and is widely expressed on many cells, including dendritic cells (DCs), which are potent antigen-presenting cells (APCs). TLR5 modulates susceptibility to obesity and alters metabolism through gut microbiota; however, little is known about the role TLR5 plays in autoimmunity, especially in T1D.

Methods

To fill this knowledge gap, we generated a TLR5-deficient non-obese diabetic (NOD) mouse, an animal model of human T1D, for study.

Results

We found that TLR5-deficiency led to a reduction in CD11c+ DC development in utero, prior to microbial colonization, which was maintained into adulthood. This was associated with a bias in the DC populations expressing CD103, with or without CD8α co-expression, and hyper-secretion of different cytokines, both in vitro (after stimulation) and directly ex vivo. We also found that TLR5-deficient DCs were able to promote polyclonal and islet antigen-specific CD4+ T cell proliferation and proinflammatory cytokine secretion. Interestingly, only older TLR5-deficient NOD mice had a greater risk of developing spontaneous T1D compared to wild-type mice.

Discussion

In summary, our data show that TLR5 modulates DC development and enhances cytokine secretion and diabetogenic CD4+ T cell responses. Further investigation into the role of TLR5 in DC development and autoimmune diabetes may give additional insights into the pathogenesis of Type 1 diabetes.

Associations of nighttime light exposure during pregnancy with maternal and neonatal gut microbiota: A cohort study

BACKGROUND

Nighttime light (NTL) pollution has been reported as a risk factor for human health. However, the relationship between NTL and gut microbiota has not been reported in pregnant women and neonates. This study was conducted to investigate the relationship between NTL and gut microbial diversity and composition in mothers and their neonates.

METHODS

This study analyzed 44 mothers and 28 newborns. The composition of gut microbiota was evaluated using 16S rRNA V3-V4 sequencing. The monthly mean NTL exposure during pregnancy was respectively calculated based on each participant's residential address (NTLpoint) and a concentric 1 km radius buffer zone around their address (NTL1000m). The relationships between NTL exposure and gut microbiota of mothers and newborns were assessed using generalized linear models.

RESULTS

NTL exposure during pregnancy was not associated with alpha diversity of mothers or neonates. For mothers, results revealed that after adjusting for covariates, NTLpoint was negatively correlated with Prevotella_2 (p = 0.004, FDR-adjusted p = 0.030) and norank_o__Gastranaerophilales (p = 0.018, FDR-adjusted p = 0.049) at the genus level. In addition, Lachnospira (p = 0.036, FDR-adjusted p = 0.052) and Coprococcus_3 (p = 0.025, FDR-adjusted p = 0.052) were positively correlated with NTLpoint. The association between Coprococcus_3 (p = 0.01, FDR-adjusted p = 0.046) and NTLpoint persisted even after controlling for covariates. For neonates, Thauera was positively associated with NTLpoint (p = 0.015) and NTL1000m (p = 0.028), however, after adjusting for covariates and FDR correction, Thauera was not significantly associated with NTLpoint and NTL1000m.

CONCLUSIONS

This study found that NTL exposure was associated with maternal gut microbiota composition. Our findings provide a foundation for the potential impact of NTL exposure on maternal gut microbiota from a microbiological perspective. More population-based validation of the effects of NTL exposure on human gut microbiota is needed in future.

Diabetic Pneumopathy- A Novel Diabetes-associated Complication: Pathophysiology, the Underlying Mechanism and Combination Medication

BACKGROUND

The "diabetic lung" has been identified as a possible target organ in diabetes, with abnormalities in ventilation control, bronchomotor tone, lung volume, pulmonary diffusing capacity, and neuroadrenergic bronchial innervation.

OBJECTIVE

This review summarizes studies related to diabetic pneumopathy, pathophysiology and a number of pulmonary disorders including type 1 and type 2 diabetes.

METHODS

Electronic searches were conducted on databases such as Pub Med, Wiley Online Library (WOL), Scopus, Elsevier, ScienceDirect, and Google Scholar using standard keywords "diabetes," "diabetes Pneumopathy," "Pathophysiology," "Lung diseases," "lung infection" for review articles published between 1978 to 2023 very few previous review articles based their focus on diabetic pneumopathy and its pathophysiology.

RESULTS

Globally, the incidence of diabetes mellitus has been rising. It is a chronic, progressive metabolic disease. The "diabetic lung" may serve as a model of accelerated ageing since diabetics' rate of respiratory function deterioration is two to three-times higher than that of normal, non-smoking people.

CONCLUSION

Diabetes-induced pulmonary dysfunction has not gained the attention it deserves due to a lack of proven causality and changes in cellular properties. The mechanism underlying a particular lung illness can still only be partially activated by diabetes but there is evidence that hyperglycemia is linked to pulmonary fibrosis in diabetic people.

The potential mechanism of gut microbiota-microbial metabolites-mitochondrial axis in progression of diabetic kidney disease

Diabetic kidney disease (DKD), has become the main cause of end-stage renal disease (ESRD) worldwide. Lately, it has been shown that the onset and advancement of DKD are linked to imbalances of gut microbiota and the abnormal generation of microbial metabolites. Similarly, a body of recent evidence revealed that biological alterations of mitochondria ranging from mitochondrial dysfunction and morphology can also exert significant effects on the occurrence of DKD. Based on the prevailing theory of endosymbiosis, it is believed that human mitochondria originated from microorganisms and share comparable biological characteristics with the microbiota found in the gut. Recent research has shown a strong correlation between the gut microbiome and mitochondrial function in the occurrence and development of metabolic disorders. The gut microbiome's metabolites may play a vital role in this communication. However, the relationship between the gut microbiome and mitochondrial function in the development of DKD is not yet fully understood, and the role of microbial metabolites is still unclear. Recent studies are highlighted in this review to examine the possible mechanism of the gut microbiota-microbial metabolites-mitochondrial axis in the progression of DKD and the new therapeutic approaches for preventing or reducing DKD based on this biological axis in the future.

Assessment of glucocorticoid and antibiotic exposure as risk factors for diabetes mellitus in selected dog breeds attending UK primary-care clinics

BACKGROUND

Diabetes mellitus (DM) is an important endocrine disorder in dogs. This study explored prior exposure to glucocorticoids or antibiotic treatment as risk factors for developing DM in dogs attending primary-care VetCompass clinics in the UK.

METHODS

A breed frequency matched case-control study nested in a cohort of dogs (n = 480,469) aged 3 years or over was used to explore associations between glucocorticoid and antibiotic exposure and the odds of developing DM.

RESULTS

A total of 565 cases and 2179 controls were included. Dogs with DM had over four times the odds of exposure to glucocorticoids within 6 weeks prior to diagnosis (odds ratio [OR] 4.07, 95% confidence interval [CI] 2.41-6.89, p < 0.001) compared to controls within 6 weeks prior to a randomly selected quasi-date of diagnosis. Dogs that had only one unique documented antibiotic course had a decreased odds of developing DM (OR 0.65, 95% CI 0.46-0.91, p = 0.012) compared to dogs that had no documented courses of antibiotics.

LIMITATIONS

This study only included selected breeds, so the results may not be generalisable to all dog breeds.

CONCLUSIONS

Exposure to glucocorticoids is associated with a substantial increase in the risk of developing DM for the dog breeds included in this analysis.

NLRP6 deficiency expands a novel CD103+ B cell population that confers immune tolerance in NOD mice

Introduction

Gut microbiota have been linked to modulating susceptibility to Type 1 diabetes; however, there are many ways in which the microbiota interact with host cells, including through microbial ligand binding to intracellular inflammasomes (large multi-subunit proteins) to initiate immune responses. NLRP6, a microbe-recognizing inflammasome protein, is highly expressed by intestinal epithelial cells and can alter susceptibility to cancer, obesity and Crohn's disease; however, the role of NLRP6 in modulating susceptibility to autoimmune diabetes, was previously unknown.

Methods

We generated NLRP6-deficient Non-obese diabetic (NOD) mice to study the effect of NLRP6-deficiency on the immune cells and susceptibility to Type 1 diabetes development.

Results

NLRP6-deficient mice exhibited an expansion of CD103+ B cells and were protected from type 1 diabetes. Moreover, NLRP6-deficient CD103+ B cells express regulatory markers, secreted higher concentrations of IL-10 and TGFb1 cytokines and suppressed diabetogenic T cell proliferation, compared to NLRP6-sufficient CD103+ B cells. Microarray analysis of NLRP6-sufficient and -deficient CD103+ B cells identified 79 significantly different genes including genes regulated by lipopolysaccharide (LPS), tretinoin, IL-10 and TGFb, which was confirmed in vitro following LPS stimulation. Furthermore, microbiota from NLRP6-deficient mice induced CD103+ B cells in colonized NLRP6-sufficient germ-free mice; however, the long-term maintenance of the CD103+ B cells required the absence of NLRP6 in the hosts, or continued exposure to microbiota from NLRP6-deficient mice.

Discussion

Together, our data indicate that NLRP6 deficiency promotes expansion and maintenance of a novel TGF -dependent CD103+ Breg population. Thus, targeting NLRP6 therapeutically may prove clinically useful.

The emerging role of noncoding RNAs in systemic lupus erythematosus: new insights into the master regulators of disease pathogenesis

Auto-immune diseases are a form of chronic disorders in which the immune system destroys the body's cells due to a loss of tolerance to self-antigens. Systemic lupus erythematosus (SLE), identified by the production of autoantibodies in different body parts, is one of the most well-known examples of these diseases. Although the etiology of SLE is unclear, the disease's progression may be affected by genetic and environmental factors. As studies in twins provide adequate evidence for genetic involvement in the SLE, other phenomena such as metallization, histone modifications, and alterations in the expression of noncoding RNAs (ncRNAs) also indicate the involvement of epigenetic factors in this disease. Among all the epigenetic alterations, ncRNAs appear to have the most crucial contribution to the pathogenesis of SLE. The ncRNAs' length and size are divided into three main classes: micro RNAs, long noncoding RNAs (LncRNA), and circular RNAs (circRNAs). Accumulating evidence suggests that dysregulations in these ncRNAs contributed to the pathogenesis of SLE. Hence, clarifying the function of these groups of ncRNAs in the pathophysiology of SLE provides a deeper understanding of the disease. It also opens up new opportunities to develop targeted therapies for this disease.

Effect of "maccog" TCM tea on improving glucolipid metabolism and gut microbiota in patients with type 2 diabetes in community

OBJECTIVES

This work aimed to observe the effect of consuming Chinese herb tea on glucolipid metabolism and gut microbiota in patients with type 2 diabetes mellitus (T2DM).

METHODS

Ninety patients with T2DM were recruited from a community and randomly divided into the control group (CG) and intervention group (IG). CG maintained conventional treatment and lifestyle, and IG accepted additional "maccog" traditional Chinese medicine (TCM) tea (mulberry leaf, radix astragali, corn stigma, cortex lycii, radix ophiopogonis, and gynostemma) for 12 weeks. Glucolipid metabolism, hepatorenal function, and gut microbiota were then measured.

RESULTS

After the intervention, the decreases in fasting plasma glucose (FPG) and total cholesterol (TC) were greater (P<0.05) in IG than in CG, and those in glycosylated serum protein (GSP) were almost significantly greater (P=0.066) in IG than in CG. The total protein (TP), albumin (ALB), and creatinine (CREA) levels in IG were significantly lower and their decreases were larger in IG than in CG (P<0.05) after the intervention. The Ace and Chao1 indices in IG were slightly higher after the intervention (P=0.056 and 0.052, respectively) than at baselines. The abundance of Actinobacteria, Lachnospiraceae, Bifidobacteriaceae, and Phascolarctobacterium increased significantly after the intervention in IG (P<0.05), and the abundance was higher in IG than in CG (P<0.05 or P<0.1). The abundance of Clostridiales and Lactobacillales was negatively correlated with FPG (P<0.05), Clostridiales and Lachnospiraceae was negatively correlated with GSP (P<0.05), and Bacteroides/Firmicutes was positively correlated with both (P<0.05). No adverse event was observed during the intervention.

CONCLUSIONS

Administration of "maccog" TCM tea for 12 weeks slightly improved glucolipid metabolism and significantly increased the abundance of beneficial gut microbiota in community patients with T2DM. The increase in beneficial bacteria abundance may be involved in the improvement of glucose metabolism indicators. In addition, this intervention is safe and feasible.

CLINICAL TRIAL REGISTRATION

https://www.chictr.org.cn/showproj.aspx?proj=31281, identifier ChiCTR1800018566.

Role of gut microbiota in the pathogenesis and treatment of diabetes mullites: Advanced research-based review

Gut microbiota plays an important role in the proper functioning of human organisms, while its dysbiosis is associated with disease in various body organs. Diabetes mellitus (DM) is a set of heterogeneous metabolic diseases characterized by hyperglycemia caused by direct or indirect insulin deficiency. There is growing evidence that gut microbiota dysbiosis is closely linked to the development of DM. Gut microbiota composition changes in type 1 diabetes mullites (T1DM) and type 2 diabetes mullites (T2DM) patients, which may cause gut leakiness and uncontrolled entry of antigens into the circulation system, triggering an immune response that damages the isle β cells or metabolic disorders. This review summarizes gut microbiota composition in healthy individuals and compares it to diabetes mullites patients. The possible pathogenesis by which gut microbiota dysbiosis causes DM, particularly gut leakiness and changes in gut microbiota metabolites is also discussed. It also presents the process of microbial-based therapies of DM.

Longitudinal analysis of the rectal microbiome in dogs with diabetes mellitus after initiation of insulin therapy

There have been numerous studies in humans and rodents substantiating the role of the gastrointestinal microbiome in the pathogenesis and progression of both type 1 and type 2 diabetes mellitus. Diabetes mellitus is a common endocrinopathy in dogs; however, little is known about the composition of the gut microbiome during the development and treatment of diabetes in this species. The objective of this pilot study was to characterize the gastrointestinal microbiome of dogs with diabetes mellitus at the time of diagnosis and over the first 12 weeks of insulin therapy and identify associations with glycemic control. Rectal swabs and serum for fructosamine measurement were collected from 6 newly diagnosed diabetic dogs at 2-week intervals for 12 weeks. Rectal samples were sequenced using 16S, ITS, and archaeal primers. Measures of alpha and beta diversity were assessed for changes over time; associations between absolute sequence variant (ASV) relative abundances and time and fructosamine concentration were identified using a microbiome-specific, multivariate linear effects model. No statistically significant changes over time were noted in alpha diversity and samples significantly grouped by dog rather than by time in the beta diversity analysis. However, multiple ASVs were negatively (Clostridium sensu stricto 1, Romboutsia, Collinsella) and positively (Streptococcus, Bacteroides, Ruminococcus gauveauii, Peptoclostridium) associated with time and two ASVs were positively associated with fructosamine (Enterococcus, Escherichia-Shigella). These changes in gastrointestinal microbial composition warrant further investigation of how they may relate to diabetes mellitus progression or control in dogs.

Fecal microbiota transplantation treatment of autoimmune-mediated type 1 diabetes mellitus

Type 1 diabetes mellitus (T1DM) is an autoimmune-mediated disease characterized by a reduced or absolute lack of insulin secretion and often associated with a range of vascular and neurological complications for which there is a lack of effective treatment other than lifestyle interventions and pharmacological treatments such as insulin injections. Studies have shown that the gut microbiota is involved in mediating the onset and development of many fecal and extrafecal diseases, including autoimmune T1DM. In recent years, many cases of gut microbiota transplantation for diseases of the bowel and beyond have been reported worldwide, and this approach has been shown to be safe and effective. Here, we conducted an experimental treatment study in two adolescent patients diagnosed with autoimmune T1DM for one year. Patients received one to three rounds of normal fecal microbiota transplants (FMT) and were followed for up to 30 weeks. Clinical outcomes were measured, including biochemical indices, medication regimen, and dosage adjustment. Fecal microbiota metagenomic sequencing after transplantation provides a reference for more reasonable and effective microbiota transplantation protocols to treat autoimmune T1DM. Our results suggest that FMT is an effective treatment for autoimmune T1DM.

CLINICAL TRIAL REGISTRATION

http://www.chictr.org.cn, identifier ChiCTR2100045789.

IgM-associated gut bacteria in obesity and type 2 diabetes in C57BL/6 mice and humans

AIMS/HYPOTHESIS

IgM is the primary antibody produced by B cells and we hypothesise that IgM antibodies to gut microbiota may play a role in immunometabolism in obesity and type 2 diabetes. To test our hypothesis, we used B6 mice deficient in activation-induced cytidine deaminase (Aid-/- [also known as Aicda-/-]) which secrete only IgM antibodies, and human faecal samples.

METHODS

We studied the immunometabolic effects and gut microbial changes in high-fat-diet-induced obesity (HFDIO) in Aid-/- B6 mice compared with wild-type mice. To determine similarities between mice and humans, human stool samples were collected from children and adolescents who were obese with normal glucose tolerance (NGT), obese with glucose intolerance (IGT), or obese and newly diagnosed with type 2 diabetes, for faecal microbiota transplant (FMT) into germ-free (GF) B6 mice and we assessed IgM-bound bacteria and immune responses.

RESULTS

Compared with wild-type mice, Aid-/- B6 mice developed exacerbated HFDIO due to abundant levels of IgM. FMT from Aid-/- B6 to GF B6 mice promoted greater weight gain in recipient mice compared with FMT using wild-type mouse faecal microbiota. Obese youth with type 2 diabetes had more IgM-bound gut bacteria. Using the stools from the obese youth with type 2 diabetes for FMT to GF B6 mice, we observed that the gut microbiota promoted body weight gain and impaired glucose tolerance in the recipient GF B6 mice. Importantly, some clinical features of these obese young individuals were mirrored in the GF B6 mice following FMT.

CONCLUSIONS/INTERPRETATION

Our results suggest that IgM-bound gut microbiota may play an important role in the immuno-pathogenesis of obesity and type 2 diabetes, and provide a novel link between IgM in obesity and type 2 diabetes in both mice and humans.

DATA AVAILABILITY

The 16s rRNA sequencing datasets supporting the current study have been deposited in the NCBI SRA public repository ( https://www.ncbi.nlm.nih.gov/sra ; accession no. SAMN18796639).

Extracellular Vesicles in Type 1 Diabetes: A Versatile Tool

Type 1 diabetes is a chronic autoimmune disease affecting nearly 35 million people. This disease develops as T-cells continually attack the β-cells of the islets of Langerhans in the pancreas, which leads to β-cell death, and steadily decreasing secretion of insulin. Lowered levels of insulin minimize the uptake of glucose into cells, thus putting the body in a hyperglycemic state. Despite significant progress in the understanding of the pathophysiology of this disease, there is a need for novel developments in the diagnostics and management of type 1 diabetes. Extracellular vesicles (EVs) are lipid-bound nanoparticles that contain diverse content from their cell of origin and can be used as a biomarker for both the onset of diabetes and transplantation rejection. Furthermore, vesicles can be loaded with therapeutic cargo and delivered in conjunction with a transplant to increase cell survival and long-term outcomes. Crucially, several studies have linked EVs and their cargos to the progression of type 1 diabetes. As a result, gaining a better understanding of EVs would help researchers better comprehend the utility of EVs in regulating and understanding type 1 diabetes. EVs are a composition of biologically active components such as nucleic acids, proteins, metabolites, and lipids that can be transported to particular cells/tissues through the blood system. Through their varied content, EVs can serve as a flexible aid in the diagnosis and management of type 1 diabetes. In this review, we provide an overview of existing knowledge about EVs. We also cover the role of EVs in the pathogenesis, detection, and treatment of type 1 diabetes and the function of EVs in pancreas and islet β-cell transplantation.

Gut Dysbiosis in Pancreatic Diseases: A Causative Factor and a Novel Therapeutic Target

Pancreatic-related disorders such as pancreatitis, pancreatic cancer, and type 1 diabetes mellitus (T1DM) impose a substantial challenge to human health and wellbeing. Even though our understanding of the initiation and progression of pancreatic diseases has broadened over time, no effective therapeutics is yet available for these disorders. Mounting evidence suggests that gut dysbiosis is closely related to human health and disease, and pancreatic diseases are no exception. Now much effort is under way to explore the correlation and eventually potential causation between the gut microbiome and the course of pancreatic diseases, as well as to develop novel preventive and/or therapeutic strategies of targeted microbiome modulation by probiotics, prebiotics, synbiotics, postbiotics, and fecal microbiota transplantation (FMT) for these multifactorial disorders. Attempts to dissect the intestinal microbial landscape and its metabolic profile might enable deep insight into a holistic picture of these complex conditions. This article aims to review the subtle yet intimate nexus loop between the gut microbiome and pancreatic diseases, with a particular focus on current evidence supporting the feasibility of preventing and controlling pancreatic diseases via microbiome-based therapeutics and therapies.

The Role of the Gut Microbiota in the Pathogenesis of Diabetes

Diabetes mellitus is a significant clinical and therapeutic problem because it can lead to serious long-term complications. Its pathogenesis is not fully understood, but there are indications that dysbiosis can play a role in the development of diabetes, or that it appears during the course of the disease. Changes in microbiota composition are observed in both type 1 diabetes (T1D) and type 2 diabetes (T2D) patients. These modifications are associated with pro-inflammation, increased intestinal permeability, endotoxemia, impaired β-cell function and development of insulin resistance. This review summarizes the role of the gut microbiota in healthy individuals and the changes in bacterial composition that can be associated with T1D or T2D. It also presents new developments in diabetes therapy based on influencing the gut microbiota as a promising method to alter the course of diabetes. Moreover, it highlights the lacking data and suggests future directions needed to prove the causal relationship between dysbiosis and diabetes, both T1D and T2D.

Antidiabetic effect of an engineered bacterium Lactobacillus plantarum-pMG36e -GLP-1 in monkey model

Glucagon-like peptide-1 (GLP-1) reduces postprandial hyperglycaemia, but its short half-life inhibits clinical application. The aim of the current study was to evaluate the treatment efforts of an engineered strain, Lactobacillus plantarum-pMG36e-GLP-1 (L. plantarum-pMG36e-GLP-1), that continuously expresses GLP-1 in spontaneous type 2 diabetes mellitus (T2DM) monkeys. After 7 weeks of oral supplementation with L. plantarum-pMG36e-GLP-1, the fasting blood glucose (FPG) of monkeys was significantly (p < 0.05) reduced to a normal level and only a small amount of weight was lost. The results of metagenomic sequencing showed that L. plantarum-pMG36e-GLP-1 caused a substantial (p < 0.05) reduction in the intestinal pathogen Prevotella and marked enhancement of butyrate-producing Alistipes genera. According to the functional analysis using Kyoto Encyclopaedia of Genes and Genomes (KEGG) pathways, 19 metabolism-related pathways were significantly enriched in T2DM monkeys after treatment with L. plantarum-pMG36e-GLP-1. LC-MS faecal metabolomics analysis found 41 significant differential metabolites (11 higher and 30 lower) in monkeys after treatment pathways linked to the metabolism of cofactors and vitamins were the most relevant. The present study suggests that L. plantarum-pMG36e-GLP-1 had an impact on the gut microbial composition and faecal metabolomic profile in spontaneous T2DM monkeys and may be a novel candidate for diabetes treatment.

Sequential Extraction, Characterization, and Analysis of Pumpkin Polysaccharides for Their Hypoglycemic Activities and Effects on Gut Microbiota in Mice

This study aimed to extract polysaccharides from pumpkin, characterize the structures of four of them, and evaluate their in vitro antioxidant and hypoglycemic activities. Additionally, an animal model of type 2 diabetes mellitus (T2DM) was established and used to determine their hypoglycemic and hypolipidemic effects in vivo, and the underlying mechanisms related to the regulation of gut microbiota. Water-extracted crude pumpkin polysaccharides (W-CPPs), water extraction and alcohol precipitation crude pumpkin polysaccharides (WA-CPPs), deproteinized pumpkin polysaccharides (DPPs), and refined pumpkin polysaccharides (RPPs) were sequentially extracted and purified from pumpkin powder by hot water extraction, water extraction, and alcohol precipitation, deproteinization and DEAE-52 cellulose gel column, respectively. The extraction and purification methods had significant influence on the extraction yield, physicochemical properties, and in vitro antioxidant and hypoglycemic activities. W-CCP and RPPs had a significant positive free radical-scavenging capacities and inhibitory activities on α-glucosidase and α-amylase. RPP-3 not only inhibited the uptake of glucose in Caco-2 monolayer but also promoted the excretion of glucose, while RPP-2 had no inhibitory effect. Animal experiment results showed that W-CPP treatment significantly improved the T2DM symptoms in mice, which included lowering of fasting blood glucose (FBG), reducing insulin resistance (IR), and lowering of blood lipid levels. It increased the diversity of intestinal flora and reduced the harmful flora of model mice, which included Clostridium, Thermoanaerobe, Symbiotic bacteria, Deinococcus, Vibrio haematococcus, Proteus gamma, and Corio. At the family level, W-CPP (1,200 mg/kg) treatment significantly reduced the abundance of Erysipelotrichaceae, and the Akkermanaceae of Verrucobacterium became a biomarker. Pumpkin polysaccharides reshaped the intestinal flora by reducing Erysipelotrichaceae and increasing Akkermansia abundance, thereby improving blood glucose and lipid metabolism in the T2DM mice. Our results suggest that W-CCP and RPP-3 possess strong antioxidant and hypoglycemic activities, and are potential candidates for food additives or natural medicines.

Pharmacological insights into autophagy modulation in autoimmune diseases

As a cellular bulk degradation and survival mechanism, autophagy is implicated in diverse biological processes. Genome-wide association studies have revealed the link between autophagy gene polymorphisms and susceptibility of autoimmune diseases including systemic lupus erythematosus (SLE) and inflammatory bowel disease (IBD), indicating that autophagy dysregulation may be involved in the development of autoimmune diseases. A series of autophagy modulators have displayed protective effects on autoimmune disease models, highlighting the emerging role of autophagy modulators in treating autoimmune diseases. This review explores the roles of autophagy in the autoimmune diseases, with emphasis on four major autoimmune diseases [SLE, rheumatoid arthritis (RA), IBD, and experimental autoimmune encephalomyelitis (EAE)]. More importantly, the therapeutic potentials of small molecular autophagy modulators (including autophagy inducers and inhibitors) on autoimmune diseases are comprehensively analyzed.

The Modulation of Gut Microbiota Composition in the Pathophysiology of Gestational Diabetes Mellitus: A Systematic Review

Simple Summary

Recent studies have placed a great deal of emphasis on the importance of the microbiome, especially the link between the alteration of gut microbiota and multiple associated diseases. Gut microbiota changes in pregnancy have a significant impact on metabolic function and may contribute to gestational diabetes mellitus (GDM). Although GDM carries long-term health risks that affect women, there are also significant short- and severe long-term consequences for the offspring. Regardless, there is a notable lack of research focusing on the impact of prominent microorganisms involved in the development of GDM. A comprehensive review was conducted to gather relevant data on the types of microorganisms that have been associated with GDM. The review found that certain microorganisms impact the onset and progression of GDM during pregnancy. Several bacterial strains associated with GDM are influenced by a diet high in fat and low in fiber. Therefore, integrating the idea of a microbiome-based individualized dietary intervention into gestational diabetes management may be incredibly beneficial.

Abstract

General gut microbial dysbiosis in diabetes mellitus, including gestational diabetes mellitus (GDM), has been reported in a large body of literature. However, evidence investigating the association between specific taxonomic classes and GDM is lacking. Thus, we performed a systematic review of peer-reviewed observational studies and trials conducted among women with GDM within the last ten years using standard methodology. The National Institutes of Health (NIH) quality assessment tools were used to assess the quality of the included studies. Fourteen studies investigating microbial interactions with GDM were found to be relevant and included in this review. The synthesis of literature findings demonstrates that Bacteroidetes, Proteobacteria, Firmicutes, and Actinobacteria phyla, such as Desulfovibrio, Ruminococcaceae, P. distasonis, Enterobacteriaceae, Collinsella, and Prevotella, were positively associated with GDM. In contrast, Bifidobacterium and Faecalibacterium, which produce butyrate, are negatively associated with GDM. These bacteria were associated with inflammation, adiposity, and glucose intolerance in women with GDM. Lack of good diet management demonstrated the alteration of gut microbiota and its impact on GDM glucose homeostasis. The majority of the studies were of good quality. Therefore, there is great potential to incorporate personalized medicine targeting microbiome modulation through dietary intervention in the management of GDM.

Microbiome reduction prevents lipid accumulation during early diapause in the northern house mosquito, Culex pipiens pipiens

The mosquito microbiome is critical to multiple facets of their biology, including larval development and disease transmission. For mosquitoes that reside in temperate regions, periods of diapause are critical to overwintering survival, but how the microbiome impacts this state is unknown. In this study, we compared the midgut microbial communities of diapausing and non-diapausing Culex pipiens and assessed how a reduced midgut microbiome influences diapause preparation. High community variability was found within and between non-diapausing and diapausing individuals, but no specific diapause-based microbiome was noted. Emergence of adult, diapausing mosquitoes under sterile conditions generated low bacterial load (LBL) lines with nearly a 1000-fold reduction in bacteria levels. This reduction in bacterial content resulted in significantly lower survival of diapausing females after two weeks, indicating acquisition of the microbiome in adult females is critical for survival throughout diapause. LBL diapausing females had high carbohydrate levels, but did not accumulate lipid reserves, suggesting an inability to process ingested sugars necessary for diapause-associated lipid accumulation. Expression patterns of select genes associated with mosquito lipid metabolism during diapause showed no significant differences between LBL and control lines, suggesting transcriptional changes may not underlie impaired lipid accumulation. Overall, a diverse, adult-acquired microbiome is critical for diapause in C. pipiens to process sugar reserves and accumulate lipids that are necessary to survive prolonged overwintering.

Gut microbiota and gestational Diabetes Mellitus: A systematic review

BACKGROUND

Gestational Diabetes Mellitus (GDM) is one of the most prevalent complications of pregnancy and can cause adverse maternal and fetal outcomes. The maternal gut microbiota is involved in several metabolic functions, but it is not yet known its role in GDM physiopathology. This study aims to review the role of gut microbiota in pregnancies that evolved with GDM.

METHODS

Systematic search of the PubMed, Embase, and Scopus databases was performed to identify articles published until 18th August 2021 involving the assessment of gut microbiota in pregnancy.

RESULTS

A total of 23 articles were selected for this review. Seventeen studies investigated differences in the gut microbiota of healthy and GDM pregnant women and showed differences in alfa and beta diversity. Six prospective studies found that microbiota changes during pregnancy and showed that some particularities in the microbiome in are associated with the risk of GDM.

CONCLUSION

This systematic review showed that there is a relationship between intestinal microbiota and GDM. Gut microbiota could be a biomarker for early detection of GDM and could be considered a potential target for modification to reduce the risk of GDM.

Gut Microbiota Composition and Its Metabolites in Different Stages of Chronic Kidney Disease

A growing body of study have documented the association of gut dysbiosis or fecal metabolites with chronic kidney disease (CKD). However, it is not clear whether the phenomenon simply reflects the microenvironment changes correlated with the CKD severity or contributes to the progression of CKD. In this study, we identified the gut microbiota and metabolite in feces samples correlated with CKD severity using the Nanopore long-read sequencing platform and UPLC-coupled MS/MS approach. A cross-sectional cohort study was performed from 1 June 2020 to 31 December 2020. One hundred and fifty-six clinical participants, including 60 healthy enrollees and 96 Stage 1–5 CKD patients, were enrolled in this study. The ROC curve generated with the relative abundance of Klebsiella pneumonia or S-Adenosylhomocysteine showed a gradual increase with the CKD severity. Our results further revealed the positive correlation of increased K. pneumonia and S-Adenosylhomocysteine in gut environment, which may be of etiological importance to the deterioration of a CKD patient. In that sense, the microbiota or metabolite changes constitute potential candidates for evaluating the progression of CKD.

Therapeutic Strategies for Diabetes: Immune Modulation in Pancreatic β Cells

Increased incidence of type I and type II diabetes has been prevailed worldwide. Though the pathogenesis of molecular mechanisms remains still unclear, there are solid evidence that disturbed immune homeostasis leads to pancreatic β cell failure. Currently, autoimmunity and uncontrolled inflammatory signaling pathways have been considered the major factors in the pathogenesis of diabetes. Many components of immune system have been reported to implicate pancreatic β cell failure, including helper T cells, cytotoxic T cells, regulatory T cells and gut microbiota. Immune modulation of those components using small molecules and antibodies, and fecal microbiota transplantation are undergoing in many clinical trials for the treatment of type I and type II diabetes. In this review we will discuss the basis of molecular pathogenesis focusing on the disturbed immune homeostasis in type I and type II diabetes, leading to pancreatic β cell destruction. Finally, we will introduce current therapeutic strategies and clinical trials by modulation of immune system for the treatment of type I and type II diabetes patients.

Gut microbiota in pancreatic diseases: possible new therapeutic strategies

Pancreatic diseases such as pancreatitis, type 1 diabetes and pancreatic cancer impose substantial health-care costs and contribute to marked morbidity and mortality. Recent studies have suggested a link between gut microbiota dysbiosis and pancreatic diseases; however, the potential roles and mechanisms of action of gut microbiota in pancreatic diseases remain to be fully elucidated. In this review, we summarize the evidence that supports relationship between alterations of gut microbiota and development of pancreatic diseases, and discuss the potential molecular mechanisms of gut microbiota dysbiosis in the pathogenesis of pancreatic diseases. We also propose current strategies toward gut microbiota to advance a developing research field that has clinical potential to reduce the cost of pancreatic diseases.

MAIT Cells and Microbiota in Multiple Sclerosis and Other Autoimmune Diseases

The functions of mucosal-associated invariant T (MAIT) cells in homeostatic conditions include the interaction with the microbiota and its products, the protection of body barriers, and the mounting of a tissue-repair response to injuries or infections. Dysfunction of MAIT cells and dysbiosis occur in common chronic diseases of inflammatory, metabolic, and tumor nature. This review is aimed at analyzing the changes of MAIT cells, as well as of the microbiota, in multiple sclerosis and other autoimmune disorders. Common features of dysbiosis in these conditions are the reduced richness of microbial species and the unbalance between pro-inflammatory and immune regulatory components of the gut microbiota. The literature concerning MAIT cells in these disorders is rather complex, and sometimes not consistent. In multiple sclerosis and other autoimmune conditions, several studies have been done, or are in progress, to find correlations between intestinal permeability, dysbiosis, MAIT cell responses, and clinical biomarkers in treated and treatment-naïve patients. The final aims are to explain what activates MAIT cells in diseases not primarily infective, which interactions with the microbiota are potentially pathogenic, and their dynamics related to disease course and disease-modifying treatments.

Pyridostigmine Protects Against Diabetic Cardiomyopathy by Regulating Vagal Activity, Gut Microbiota, and Branched-Chain Amino Acid Catabolism in Diabetic Mice

The disruption of gut microbes is associated with diabetic cardiomyopathy, but the mechanism by which gut microbes affect cardiac damage remains unclear. We explored gut microbes and branched-chain amino acid (BCAA) metabolite catabolism in diabetic cardiomyopathy mice and investigated the cardioprotective effect of pyridostigmine. The experiments were conducted using a model of diabetic cardiomyopathy induced by a high-fat diet + streptozotocin in C57BL/6 mice. The results of high-throughput sequencing showed that diabetic cardiomyopathy mice exhibited decreased gut microbial diversity, altered abundance of the diabetes-related microbes, and increased abundance of the BCAA-producing microbes Clostridiales and Lachnospiraceae. In addition, diabetes downregulated tight junction proteins (ZO-1, occludin, and claudin-1) and increased intestinal permeability to impair the intestinal barrier. These impairments were accompanied by reduction in vagal activity that manifested as increased acetylcholinesterase levels, decreased acetylcholine levels, and heart rate variability, which eventually led to cardiac damage. Pyridostigmine enhanced vagal activity, restored gut microbiota homeostasis, decreased BCAA-producing microbe abundance, and improved the intestinal barrier to reduce circulating BCAA levels. Pyridostigmine also upregulated BCAT2 and PP2Cm and downregulated p-BCKDHA/BCKDHA and BCKDK to improve cardiac BCAA catabolism. Moreover, pyridostigmine alleviated abnormal mitochondrial structure; increased ATP production; decreased reactive oxygen species and mitochondria-related apoptosis; and attenuated cardiac dysfunction, hypertrophy, and fibrosis in diabetic cardiomyopathy mice. In conclusion, the gut microbiota, BCAA catabolism, and vagal activity were impaired in diabetic cardiomyopathy mice but were improved by pyridostigmine. These results provide novel insights for the development of a therapeutic strategy for diabetes-induced cardiac damage that targets gut microbes and BCAA catabolism.

Experimental infection with the hookworm, Necator americanus, is associated with stable gut microbial diversity in human volunteers with relapsing multiple sclerosis

BACKGROUND

Helminth-associated changes in gut microbiota composition have been hypothesised to contribute to the immune-suppressive properties of parasitic worms. Multiple sclerosis is an immune-mediated autoimmune disease of the central nervous system whose pathophysiology has been linked to imbalances in gut microbial communities.

RESULTS

In the present study, we investigated, for the first time, qualitative and quantitative changes in the faecal bacterial composition of human volunteers with remitting multiple sclerosis (RMS) prior to and following experimental infection with the human hookworm, Necator americanus (N+), and following anthelmintic treatment, and compared the findings with data obtained from a cohort of RMS patients subjected to placebo treatment (PBO). Bacterial 16S rRNA high-throughput sequencing data revealed significantly decreased alpha diversity in the faecal microbiota of PBO compared to N+ subjects over the course of the trial; additionally, we observed significant differences in the abundances of several bacterial taxa with putative immune-modulatory functions between study cohorts. Parabacteroides were significantly expanded in the faecal microbiota of N+ individuals for which no clinical and/or radiological relapses were recorded at the end of the trial.

CONCLUSIONS

Overall, our data lend support to the hypothesis of a contributory role of parasite-associated alterations in gut microbial composition to the immune-modulatory properties of hookworm parasites.

Modulating the Microbiota as a Therapeutic Intervention for Type 2 Diabetes

Mounting evidence suggested that the gut microbiota has a significant role in the metabolism and disease status of the host. In particular, Type 2 Diabetes (T2D), which has a complex etiology that includes obesity and chronic low-grade inflammation, is modulated by the gut microbiota and microbial metabolites. Current literature supports that unbalanced gut microbial composition (dysbiosis) is a risk factor for T2D. In this review, we critically summarize the recent findings regarding the role of gut microbiota in T2D. Beyond these associative studies, we focus on the causal relationship between microbiota and T2D established using fecal microbiota transplantation (FMT) or probiotic supplementation, and the potential underlying mechanisms such as byproducts of microbial metabolism. These microbial metabolites are small molecules that establish communication between microbiota and host cells. We critically summarize the associations between T2D and microbial metabolites such as short-chain fatty acids (SCFAs) and trimethylamine N-Oxide (TMAO). Additionally, we comment on how host genetic architecture and the epigenome influence the microbial composition and thus how the gut microbiota may explain part of the missing heritability of T2D found by GWAS analysis. We also discuss future directions in this field and how approaches such as FMT, prebiotics, and probiotics supplementation are being considered as potential therapeutics for T2D.

Akkermansia, a Possible Microbial Marker for Poor Glycemic Control in Qataris Children Consuming Arabic Diet-A Pilot Study on Pediatric T1DM in Qatar

In Qatar, Type 1 Diabetes mellitus (T1DM) is one of the most prevalent disorders. This study aimed to explore the gut microbiome's relation to the continuous subcutaneous insulin infusion (CSII) therapy, dietary habits, and the HbA1c level in the pediatric T1DM subjects in Qatar. We recruited 28 T1DM subjects with an average age of 10.5 ± 3.53 years. The stool sample was used to measure microbial composition by 16s rDNA sequencing method. The results have revealed that the subjects who had undergone CSII therapy had increased microbial diversity and genus Akkermansia was significantly enriched in the subjects without CSII therapy. Moreover, genus Akkermansia was higher in the subjects with poor glycemic control (HbA1c > 7.5%). When we classified the subjects based on dietary patterns and nationality, Akkermansia was significantly enriched in Qataris subjects without the CSII therapy consuming Arabic diet than expatriates living in Qatar and eating a Western/mixed diet. Thus, this pilot study showed that abundance of Akkermansia is dependent on the Arabic diet only in poorly controlled Qataris T1DM patients, opening new routes to personalized treatment for T1DM in Qataris pediatric subjects. Further comprehensive studies on the relation between the Arabic diet, ethnicity, and Akkermansia are warranted to confirm this preliminary finding.

The crucial role of early-life gut microbiota in the development of type 1 diabetes

Early-life healthy gut microbiota has a profound implication on shaping the mucosal immune system as well as maintaining healthy status later in life, especially at the prenatal or neonatal stages, while intestinal dysbiosis in early life is associated with several autoimmune diseases, including type 1 diabetes (T1D). Since the gut microbiome is potentially modifiable, optimizing the intestinal bacterial composition in early life may be a novel option for T1D prevention. In this review, we will review current data depicting the crucial role of early-life intestinal microbiome in the development of T1D and discuss the possible mechanisms whereby early-life intestinal microbiome influences the T1D progression. We also summarize recent findings on environmental factors affecting gut microbiota colonization and interventions that may successfully alter microbial composition to discuss potential means of preventing T1D progression in at-risk children.

Unravelling the involvement of gut microbiota in type 2 diabetes mellitus

Type 2 diabetes mellitus is the most prevalent metabolic disorder characterized by hyperglycemia, hyperlipidemia as well as insulin resistance and is affecting the lives of a huge population across the globe. Genetic mutations, obesity and lack of physical activity constitute the possible factors that can lead to onset and progression of this disorder. However, there is another major factor that can be the root cause of type 2 diabetes mellitus and that is an imbalance in the microorganisms that inhabit the gut. The gut microbiome is a vital component that needs to be given significant attention because any "dysbiosis" in the colonic microorganisms can transform the host from a state of health to a state of disease. This transformation is quite obvious since the gut barrier integrity, host metabolism such as sensitivity to insulin and maintaining blood glucose level are carried out by the tiny organisms inhabiting our intestine. In fact, the normal functioning of the human body is accredited to the microbes, particularly the bacteria, because they generate their metabolites that communicate with host cells and maintain normal physiology. Giving importance to gut health is, therefore, necessary to prevent metabolic diseases that can be maintained by the intake of prebiotics, probiotics, synbiotics along with healthy diet. The tiny microorganisms in the gut that keep our body free of disorders such as type 2 diabetes mellitus need to be in a state of 'eubiosis', else the consequences of disturbance in gut microbes can progress to serious complications in the host.

New Insights into Stroke Prevention and Treatment: Gut Microbiome

Stroke, a lethal neurological disease, accounts for a grave economic burden on society. Despite extensive basic and clinical studies on stroke prevention, a precise effective treatment approach for stroke at this stage remains unavailable. The majority of our body's gut microbiota plays a vital role in food digestion, immune regulation, and nervous system development, which is highly associated with the development of some diseases. Multiple clinical studies have documented variation in the composition of gut microbiota between stroke patients and healthy counterparts. Moreover, the intervention of intestinal symbiotic microorganisms via several mechanisms plays an active role in stroke prognosis. In the prevention and treatment of stroke, the gut microbiota gives off a seductive glow, this is a promising therapeutic target. This paper summarizes the current knowledge of stroke and gut microbiota, and systematically describes the possible mechanisms of interaction between stroke and gut microbiota, the relationship between stroke-related risk factors and gut microbiota, and the treatment of gut flora using microorganisms. Thus, it could valuably elucidate the correlation of gut microbiota with stroke incidence, providing stroke researchers with a new strategy for stroke prevention and treatment by regulating gut microbiota.

Effects of urolithins on obesity-associated gut dysbiosis in rats fed on a high-fat diet

Obesity is a global health concern associated with the dysbiosis of intestinal microbial composition. In this study, we investigated the potentials of urolithin A (Uro-A) and urolithin B (Uro-B), two gut microbiota-derived metabolites of ellagitannins, in reducing body weight gain through the modulation of the gut microbiota. We established a high-fat diet (HFD)-induced obesity model in rats that were later administered with either 2.5 mg/kg of Uro-A or Uro-B. Serum biochemical parameters were quantified, and changes in the composition of the gut microbial community were analysed using 16S rDNA gene sequencing. Our results showed that the urolithins significantly decreased the body weight in HFD-fed rats and restored serum lipid profile. The taxonomic analysis showed that both Uro-A and Uro-modulated gut microbes related to body weight, dysfunctional lipid metabolism and inflammation. Overall, our results suggest that Uro-A and Uro-B possess anti-obesity properties, which may be related to the modulation of the gut microbial composition.

Microbiota and Diabetes Mellitus: Role of Lipid Mediators

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

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

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

Psychological Stress, Intestinal Barrier Dysfunctions, and Autoimmune Disorders: An Overview

Autoimmune disorders (ADs) are multifactorial diseases involving, genetic, epigenetic, and environmental factors characterized by an inappropriate immune response toward self-antigens. In the past decades, there has been a continuous rise in the incidence of ADs, which cannot be explained by genetic factors alone. Influence of psychological stress on the development or the course of autoimmune disorders has been discussed for a long time. Indeed, based on epidemiological studies, stress has been suggested to precede AD occurrence and to exacerbate symptoms. Furthermore, compiling data showed that most of ADs are associated with gastrointestinal symptoms, that is, microbiota dysbiosis, intestinal hyperpermeability, and intestinal inflammation. Interestingly, social stress (acute or chronic, in adult or in neonate) is a well-described intestinal disrupting factor. Taken together, those observations question a potential role of stress-induced defect of the intestinal barrier in the onset and/or the course of ADs. In this review, we aim to present evidences supporting the hypothesis for a role of stress-induced intestinal barrier disruption in the onset and/or the course of ADs. We will mainly focus on autoimmune type 1 diabetes, multiple sclerosis and systemic lupus erythematosus, ADs for which we could find sufficient circumstantial data to support this hypothesis. We excluded gastrointestinal (GI) ADs like coeliac disease to privilege ADs not focused on intestinal disorders to avoid confounding factors. Indeed, GIADs are characterized by antibodies directed against intestinal barrier actors.

Gut microbiota and diabetes: From correlation to causality and mechanism

In this review, we summarize the recent microbiome studies related to diabetes disease and discuss the key findings that show the early emerging potential causal roles for diabetes. On a global scale, diabetes causes a significant negative impact to the health status of human populations. This review covers type 1 diabetes and type 2 diabetes. We examine promising studies which lead to a better understanding of the potential mechanism of microbiota in diabetes diseases. It appears that the human oral and gut microbiota are deeply interdigitated with diabetes. It is that simple. Recent studies of the human microbiome are capturing the attention of scientists and healthcare practitioners worldwide by focusing on the interplay of gut microbiome and diabetes. These studies focus on the role and the potential impact of intestinal microflora in diabetes. We paint a clear picture of how strongly microbes are linked and associated, both positively and negatively, with the fundamental and essential parts of diabetes in humans. The microflora seems to have an endless capacity to impact and transform diabetes. We conclude that there is clear and growing evidence of a close relationship between the microbiota and diabetes and this is worthy of future investments and research efforts.

MAIT cells in metabolic diseases

Background

Metabolic diseases represent a wide category of alterations affecting metabolism. These pathologies are notably marked by inflammation that implicates the immune system. Mucosal Associated Invariant (MAI)T cells are immune cells expressing a semi-invariant TCR able to recognize bacterial and fungal vitamin B metabolites. MAIT cells can promote inflammation and are present in many organs central to metabolism, suggesting a role in the etiopathology of these diseases.

Scope of the review

Here, we will review what is known of the involvement of MAIT cells in metabolic pathologies in humans and mice.

Major conclusions

MAIT cells are severely affected, overactivated with a frequency reduction and a phenotype shift from protective to deleterious. Therefore, they might be a novel target to treat, in particular, pancreas and liver metabolic diseases.

Gut microbiota dysbiosis in polycystic ovary syndrome: association with obesity - a preliminary report

The objective was to explore if and how the microbiota changed in polycystic ovary syndrome (PCOS) women compared with healthy women. Eight obese PCOS (PO group), 10 nonobese PCOS (PN group), and nine healthy normal weight women (control) (C group) were enrolled. Insulin (INS), testosterone (T), follicle-stimulating hormone (FSH), luteinizing hormone (LH), estrogen (E2), and dehydroepiandrosterone (DHEA) were detected with radioimmunoassay. Antimullerian hormone (AMH), fasting glucose, and hemoglobin A1c (HbA1c) were determined by a chemiluminescence immunoassay, glucose oxidase method, and HPLC, respectively. Gut microbiota composition was evaluated by PCR. Alpha diversity was assessed using Chao1 and the Shannon index. PCOS women showed significantly higher T, LH, and LH/FSH and lower FSH levels than the C group (p < 0.05). The AMH level was significantly higher in the PO than in the PN group (p < 0.05). The PO group presented a significantly higher fasting INS level and HMOA-IR scores than the other groups, lower observed SVs and alpha diversity than the C group, higher beta diversity than the PN group (p < 0.05), and decreased abundances of genera (mainly butyrate producers). Regression analysis showed that decreased abundances of several genera were correlated with higher circulating T and impaired glucose metabolism. PCOS is associated with changes in the gut microbiota composition. Obesity has a driving role in the development of dysbiotic gut microbiota in PCOS.

From role of gut microbiota to microbial-based therapies in type 2-diabetes

The incidence of type 2 diabetes mellitus (T2DM) has increased dramatically at an alarming level around the world.T2DM is associated with changeable risk factors in lifestyle as well as genetic and family associated risk factors. More importantly, imbalanced or impaired gut microbial distribution (dysbiosis) has been reported as a contributing risk factor in insulin resistance progression in T2DM. Dysbiosis may restructure the metabolic and functional pathways in the intestine which are involved in the development of T2DM. However, several studies have indicated the constructive and helpful effect of prebiotics, probiotics, and fecal microbiota transplantation (FMT) on the improvement of gut microbiota (GM) and accordingly host metabolism. In this review, the association between GM and T2DM have been evaluated and the role of prebiotics, probiotics and FMT, as potential therapeutic approaches have been discussed. Relevant studies were obtained randomly from online databases such as PubMed/Medline and ISI Web of Science.

A Comprehensive Review of Celiac Disease/Gluten-Sensitive Enteropathies

Celiac disease is a complex immune-mediated gluten-sensitive enteropathy with protean clinical manifestations. It is manifest in genetically predisposed individuals who ingest gluten in varying amounts. In broad terms, it is thought to affect 1% of the population in the USA. More specifically, the prevalence increases drastically from 1:133 in patients not-at-risk, to 1:56 in symptomatic patients, to 1:39 in patients with a second-degree relative with the diagnosis, and to 1:22 in patients with a first-degree relative with the diagnosis. It may be associated with several immune-mediated phenomena, autoimmune diseases, and complicated by vitamin and other trace element deficiencies, bone disease, and malignancy. Our understanding of celiac disease has evolved rapidly over the past two decades. This has led to several lines of enquiry on the condition and potential treatment options. More recently, several entities including gluten intolerance, non-celiac gluten sensitivity, and seronegative celiac disease have been described. These conditions are distinct from allergies or intolerance to wheat or wheat products. There are challenges in defining some of these entities since a large number of patients self-report these conditions. The absence of confirmatory diagnostic tests poses an added dilemma in distinguishing these entities. The differences in spectrum of symptoms and highlights of the variability between the pediatric and adult populations have been studied in some detail. The role of screening for celiac disease is examined in both the general population and "at risk" populations. Diagnostic strategies including the best available serologic testing, utility of HLA haplotypes DQ2 and DQ8 which are seen in over 90% of patients with celiac disease as compared with approximately 40% of the general population, and endoscopic evaluation are also reviewed. Comprehensive nutritional management after diagnosis is key to sustained health in patients with celiac disease. Simple algorithms for care based on a comprehensive multidisciplinary approach are proposed. Refractory and non-responsive celiac diseases in the setting of a gluten-free diet are examined as are novel non-dietary therapies. Finally, the association of other disease states including psychiatric illness, infertility, lymphoproliferative malignancy, and mortality is explored with special attention paid to autoimmune and atopic disease.

Evaluating the Causal Role of Gut Microbiota in Type 1 Diabetes and Its Possible Pathogenic Mechanisms

Type 1 diabetes (T1D) is a multifactorial autoimmune disease mediated by genetic, epigenetic, and environmental factors. In recent years, the emergence of high-throughput sequencing has allowed us to investigate the role of gut microbiota in the development of T1D. Significant changes in the composition of gut microbiome, also termed dysbiosis, have been found in subjects with clinical or preclinical T1D. However, whether the dysbiosis is a cause or an effect of the disease remains unclear. Currently, increasing evidence has supported a causal link between intestine microflora and T1D development. The current review will focus on recent research regarding the associations between intestine microbiome and T1D progression with an intention to evaluate the causality. We will also discuss the possible mechanisms by which imbalanced gut microbiota leads to the development of T1D.