Role of the gut microbiota in type 2 diabetes and related diseases

(-)-Epicatechin ameliorates type 2 diabetes mellitus by reshaping the gut microbiota and Gut-Liver axis in GK rats

As one of the most abundant plant polyphenols in the human diet, (-)-epicatechin (EC) can improve insulin sensitivity and regulate glucose homeostasis. However, the primary mechanisms involved in EC anti-T2DM benefits remain unclear. The present study explored the effects of EC on the gut microbiota and liver transcriptome in type 2 diabetes mellitus (T2DM) Goto-Kakizaki rats for the first time. The findings showed that EC protected glucose homeostasis, alleviated systemic oxidative stress, relieved liver damage, and increased serum insulin. Further investigation showed that EC reshaped gut microbiota structure, including inhibiting the proliferation of lipopolysaccharide (LPS)-producing bacteria and reducing serum LPS. In addition, transcriptome analysis revealed that the insulin signaling pathway may be the core pathway of the EC anti-T2DM effect. Therefore, EC may modulate the gut microbiota and liver insulin signaling pathways by the gut-liver axis to alleviate T2DM. As a diet supplement, EC has promising potential in T2DM prevention and treatment.

Role of gut microbiota in doxorubicin-induced cardiotoxicity: from pathogenesis to related interventions

Doxorubicin (DOX) is a broad-spectrum and highly efficient anticancer agent, but its clinical implication is limited by lethal cardiotoxicity. Growing evidences have shown that alterations in intestinal microbial composition and function, namely dysbiosis, are closely linked to the progression of DOX-induced cardiotoxicity (DIC) through regulating the gut-microbiota-heart (GMH) axis. The role of gut microbiota and its metabolites in DIC, however, is largely unelucidated. Our review will focus on the potential mechanism between gut microbiota dysbiosis and DIC, so as to provide novel insights into the pathophysiology of DIC. Furthermore, we summarize the underlying interventions of microbial-targeted therapeutics in DIC, encompassing dietary interventions, fecal microbiota transplantation (FMT), probiotics, antibiotics, and natural phytochemicals. Given the emergence of microbial investigation in DIC, finally we aim to point out a novel direction for future research and clinical intervention of DIC, which may be helpful for the DIC patients.

Hypoglycemic Effects of Gynura divaricata (L.) DC Polysaccharide and Action Mechanisms via Modulation of Gut Microbiota in Diabetic Mice

Aiming to provide a basis for the application of Gynura divaricata (L.) DC polysaccharide (GDP) in functional foods, the hypoglycemic effects of GDP, and action mechanisms, were investigated. Results showed that GDP effectively inhibited α-glucosidase and remarkably increased the glucose absorption, glycogen content, and pyruvate kinase and hexokinase activities of insulin-resistant HepG2 cells, indicating its potent in vitro hypoglycemic effect. In streptozotocin-induced type 2 diabetes mice, GDP significantly improved various glycolipid metabolism-related indices in serum and liver, e.g., fasting blood glucose, oral glucose tolerance, glycosylated serum protein content, serum insulin level, antioxidant enzyme activities, TG, TC, LDL-C, and HDL-C levels, and hepatic glycogen content, and recovered the structure of gut microbiota to the normal level. It was also found that GDP significantly affected the expression of related genes in the PI3K/Akt, AMPK, and GS/GSK-3β signaling pathways. Therefore, GDP regulates blood glucose possibly by directly inhibiting α-glucosidase, exerting antioxidant activity, and regulating intestinal microbiota.

Jiao-tai-wan and its effective component-berberine improve diabetes and depressive disorder through the cAMP/PKA/CREB signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Jiao-tai-wan (JTW), a classic herbal formula of traditional Chinese medicine recorded in Han Shi Yi Tong, has been used to alleviate sleep disorders since ancient times. In modern pharmacological research, JTW has been adopted for treating diabetes mellitus and even exerts antidepressant effects. However, the potential mechanisms deserve further elucidation.

AIM OF THE STUDY

The prevalence of diabetes mellitus combined with depressive disorder (DD) is continuing to increase, yet it is currently under-recognized and its treatment remains inadequate. The present study aims to explore the underlying therapeutics and mechanisms of JTW on DD.

MATERIALS AND METHODS

Chronic restraint stress was used on db/db mice to construct a mouse model of DD. The therapeutic effects of JTW were assessed by glucolipid metabolic indexes, behavioral tests, and depression-related neurotransmitter levels. The inflammatory status and cell apoptosis of different mice were investigated and the changes in the cAMP/PKA/CREB pathway were detected. Combining the results of fingerprinting with molecular docking, the active components of JTW were screened. A cellular model was constructed by intervention of glucose combined with corticosterone (CORT). The levels of apoptosis and depression-related neurotransmitters in HT-22 cells were examined, and the changes in the cAMP/PKA/CREB pathway were tested. Finally, the activator and inhibitor of the PKA protein were used for reverse validation experiments.

RESULTS

JTW could improve the impaired glucose tolerance, lipid metabolism disorders, and depression-like symptoms in DD mice. Meanwhile, JTW could alleviate the inflammatory status, suppress the microglia activation, and improve hippocampal neuron apoptosis in DD mice. The dual effects of JTW might be associated with the activation of the cAMP/PKA/CREB pathway. Berberine (Ber) was identified for the in vitro experiment, it could reverse the apoptosis of HT-22 cells and up-regulate the depression-related neurotransmitter levels, and the effects of Ber were related to the activation of the cAMP/PKA/CREB pathway as well.

CONCLUSION

JTW could exert both hypoglycemic and antidepressant effects through activating the cAMP/PKA/CREB signaling pathway, its active component, Ber, could improve the damage to HT-22 cells induced by glucose combined with CORT via the activation of the cAMP/PKA/CREB pathway. Ber may be one of the effective components of the dual effects of JTW.

High-altitude hypoxia promotes BRD4-mediated activation of the Wnt/β-catenin pathway and disruption of intestinal barrier

Hypobaric hypoxia, commonly experienced at elevated altitudes, presents significant physiological challenges. Our investigation is centered on the impact of the bromodomain protein 4 (BRD4) under these conditions, especially its interaction with the Wnt/β-Catenin pathway and resultant effects on glycolytic inflammation and intestinal barrier stability. By combining transcriptome sequencing with bioinformatics, we identified BRD4's key role in hypoxia-related intestinal anomalies. Clinical parameters of altitude sickness patients, including serum BRD4 levels, inflammatory markers, and barrier integrity metrics, were scrutinized. In vitro studies using CCD 841 CoN cells depicted expression changes in BRD4, Interleukin (IL)-1β, IL-6, and β-Catenin. Transepithelial electrical resistance (TEER) and FD4 analyses assessed barrier resilience. Hypoxia-induced mouse models, analyzed via H&E staining and Western blot, provided insights into barrier and protein alterations. Under hypoxic conditions, marked BRD4 expression variations emerged. Elevated serum BRD4 in patients coincided with intensified Wnt signaling, inflammation, and barrier deterioration. In vitro, findings showed hypoxia-induced upregulation of BRD4 and inflammatory markers but a decline in Occludin and ZO1, affecting barrier strength-effects mitigated by BRD4 inhibition. Mouse models echoed these patterns, linking BRD4 upregulation in hypoxia to barrier perturbations. Hypobaric hypoxia-induced BRD4 upregulation disrupts the Wnt/β-Catenin signaling, sparking glycolysis-fueled inflammation and weakening intestinal tight junctions and barrier degradation.

The potential of astragalus polysaccharide for treating diabetes and its action mechanism

Type 2 diabetes presents a significant global health burden and is frequently linked to serious clinical complications, including diabetic cardiomyopathy, nephropathy, and retinopathy. Astragalus polysaccharide (APS), extracted from Astragalus membranaceus, exhibits various biochemical and physiological effects. In recent years, a growing number of researchers have investigated the role of APS in glucose control and the treatment of diabetes and its complications in various diabetes models, positioning APS as a promising candidate for diabetes therapy. This review surveys the literature on APS from several databases over the past 20 years, detailing its mechanisms of action in preventing and treating diabetes mellitus. The findings indicate that APS can address diabetes by enhancing insulin resistance, modulating the immune system, protecting islet cells, and improving the intestinal microbiota. APS demonstrates positive pharmacological value and clinical potential in managing diabetic complications, including diabetic retinopathy, nephropathy, cardiomyopathy, cognitive dysfunction, wound healing, and more. However, further research is necessary to explore APS's bioavailability, optimal dosage, and additional clinical evidence.

The polysaccharides from seeds of Glycyrrhiza uralensis ameliorate metabolic disorders and restructure gut microbiota in type 2 diabetic mice

T2D and its complications are significant threats to human health and are among the most concerning metabolic diseases worldwide. Previous studies have revealed that Glycyrrhiza uralensis polysaccharide extract (GUP) exhibits remarkable antioxidant capabilities and inhibits alpha-glucosidase activity. However, whether GUP improves glycemic control in T2D is unknown. This study aims to investigate the effects of GUP on glucose and lipid metabolism as well as the intestinal microbiota in HFD/STZ-induced T2D. The results demonstrated that GUP could significantly ameliorate hyperglycemia, insulin resistance, oxidative stress, and reduce liver lipid levels in T2D mice. Furthermore, it also enhanced the integrity of the intestinal barrier in T2D mice by reducing the levels of pro-inflammatory cytokines and serum LPS levels. Interestingly, GUP treatment significantly lowered serum creatinine and urea nitrogen levels, mitigating renal function deterioration and interstitial fibrosis. Additionally, GUP intervention increased the α diversity of gut microbiota, promoting beneficial species like Akkermansia, Lactobacillus, Romboutsia and Faecalibaculum, while decreasing harmful ones such as Bacteroides, Escherichia-Shigella, and Clostridium sensu stricto 1 in T2D mice. Overall, this study highlights the potential of GUP in alleviating complications and enhancing intestinal health in T2D mice, providing valuable insights into dietary strategies for diabetes control and overall health improvement.

Specific Alternation of Gut Microbiota and the Role of Ruminococcus gnavus in the Development of Diabetic Nephropathy

In this study, we aim to investigate the precise alterations in the gut microbiota during the onset and advancement of diabetic nephropathy (DN) and examine the impact of Ruminococcus gnavus (R. gnavus) on DN. Eight-week-old male KK-Ay mice were administered antibiotic cocktails for a duration of two weeks, followed by oral administration of R. gnavus for an additional eight weeks. Our study revealed significant changes in the gut microbiota during both the initiation and progression of DN. Specifically, we observed a notable increase in the abundance of Clostridia at the class level, higher levels of Lachnospirales and Oscillospirales at the order level, and a marked decrease in Clostridia_UCG-014 in DN group. Additionally, there was a significant increase in the abundance of Lachnospiraceae, Oscillospiraceae, and Ruminococcaceae at the family level. Moreover, oral administration of R. gnavus effectively aggravated kidney pathology in DN mice, accompanied by elevated levels of urea nitrogen (UN), creatinine (Cr), and urine protein. Furthermore, R. gnavus administration resulted in down-regulation of tight junction proteins such as Claudin-1, Occludin, and ZO-1, as well as increased levels of uremic toxins in urine and serum samples. Additionally, our study demonstrated that orally administered R. gnavus up-regulated the expression of inflammatory factors, including nucleotide-binding oligomerization domain-like receptor pyrin domain-containing protein 3 (NLRP3) and Interleukin (IL)-6. These changes indicated the involvement of the gut-kidney axis in DN, and R. gnavus may worsen diabetic nephropathy by affecting uremic toxin levels and promoting inflammation in DN.

Association between gut microbiota and onset of type 2 diabetes mellitus: a two-sample Mendelian randomization study

Aim

Mendelian randomization (MR) analysis has been used in the exploration of the role of gut microbiota (GM) in type 2 diabetes mellitus (T2DM); however, it was limited to the genus level. This study herein aims to investigate the relationship of GM, especially at the species level, with T2DM in order to provide some evidence for further exploration of more specific GM taxa and pathway abundance in T2DM.

Methods

This two-sample MR study was based on the summary statistics of GM from the available genome-wide association study (GWAS) meta-analysis conducted by the MiBioGen consortium as well as the Dutch Microbiome Project (DMP), whereas the summary statistics of T2DM were obtained from the FinnGen consortium released data. Inverse variance weighted (IVW), MR-Egger, strength test (F), and weighted median methods were used to examine the causal association between GM and the onset of T2DM. Cochran's Q statistics was employed to quantify the heterogeneity of instrumental variables. Bonferroni's correction was conducted to correct the bias of multiple testing. We also performed reverse causality analysis.

Results

The corrected IVW estimates suggested the increased relative abundance of family Oxalobacteraceae (OR = 1.0704) and genus Oxalobacter (OR = 1.0874), respectively, were associated with higher odds of T2DM, while that of species faecis (OR = 0.9460) had a negative relationship with T2DM. The relationships of class Betaproteobacteria, family Lactobacillaceae, species finegoldii, and species longum with T2DM were also significant according to the IVW results (all P < 0.05).

Conclusions

GM had a potential causal association with T2DM, especially species faecis, finegoldii, and longum. Further studies are still needed to clarify certain results that are contradictory with previous findings.

Myricetin alleviates diabetic cardiomyopathy by regulating gut microbiota and their metabolites

BACKGROUND

The gut microbiota is involved in the pathogenesis of diabetic cardiomyopathy (DCM). Myricetin protects cardiac function in DCM. However, the low bioavailability of myricetin fails to explain its pharmacological mechanisms thoroughly. Research has shown that myricetin has a positive effect on the gut microbiota. We hypothesize that myricetin improves the development of DCM via regulating gut microbiota.

METHODS

DCM mice were induced with streptozotocin and fed a high-fat diet, and then treated with myricetin by gavage and high-fat diet for 16 weeks. Indexes related to gut microbiota composition, cardiac structure, cardiac function, intestinal barrier function, and inflammation were detected. Moreover, the gut contents were transplanted to DCM mice, and the effect of fecal microbiota transplantation (FMT) on DCM mice was assessed.

RESULTS

Myricetin could improve cardiac function in DCM mice by decreasing cardiomyocyte hypertrophy and interstitial fibrosis. The composition of gut microbiota, especially for short-chain fatty acid-producing bacteria involving Roseburia, Faecalibaculum, and Bifidobacterium, was more abundant by myricetin treatment in DCM mice. Myricetin increased occludin expression and the number of goblet cells in DCM mice. Compared with DCM mice unfed with gut content, the cardiac function, number of goblet cells, and expression of occludin in DCM mice fed by gut contents were elevated, while cardiomyocyte hypertrophy and TLR4/MyD88 pathway-related proteins were decreased.

CONCLUSIONS

Myricetin can prevent DCM development by increasing the abundance of beneficial gut microbiota and restoring the gut barrier function.

Maternal F-53B exposure during pregnancy and lactation induced glucolipid metabolism disorders and adverse pregnancy outcomes by disturbing gut microbiota in mice

In the metal plating industry, F-53B has been widely used for almost half a century as a replacement for perfluorooctane sulfonate. However, F-53B can reach the food chain and affect human health. Pregnant women have distinct physiological characteristics and may thus be more sensitive to the toxicity of F-53B. In the present study, F-53B was added to the drinking water of pregnant mice during gestation and lactation at doses of 0 mg/L (Ctrl), 0.57 mg/L (L-F), and 5.7 mg/L (H-F). The aim was to explore the potential effects of F-53B on glucolipid metabolism and pregnancy outcomes in dams. Results showed that F-53B induced disordered glucolipid metabolism, adverse pregnancy outcomes, hepatic inflammation, oxidative stress and substantially altered related biochemical parameters in maternal mice. Moreover, F-53B induced remarkable gut barrier damage and gut microbiota perturbation. Correlation analysis revealed that gut microbiota is associated with glucolipid metabolism disorders and hepatic inflammation. The fecal microbiota transplant experiment demonstrated that altered gut microbiota induced by F-53B caused metabolic disorders, adverse pregnancy outcomes, and gut barrier damage. These results suggested that maternal mice exposed to F-53B during gestation and lactation had an increased risk of developing metabolic disorders and adverse pregnancy outcomes and highlighted the crucial role of the gut microbiota in this process, offering novel insights into the risk of F-53B to health.

Role of the gut microbiota in the pathogenesis of endometriosis: a review

Endometriosis is classically defined as a chronic inflammatory heterogeneous disorder occurring in any part of the body, characterized by estrogen-driven periodic bleeding, proliferation, and fibrosis of ectopic endometrial glands and stroma outside the uterus. Endometriosis can take overwhelmingly serious damage to the structure and function of multi-organ, even impair whole-body systems, resulting in severe dysmenorrhea, chronic pelvic pain, infertility, fatigue and depression in 5-10% women of reproductive age. Precisely because of a huge deficiency of cognition about underlying etiology and complex pathogenesis of the debilitating disease, early diagnosis and treatment modalities with relatively minor side effects become bottlenecks in endometriosis. Thus, endometriosis warrants deeper exploration and expanded investigation in pathogenesis. The gut microbiota plays a significant role in chronic diseases in humans by acting as an important participant and regulator in the metabolism and immunity of the body. Increasingly, studies have shown that the gut microbiota is closely related to inflammation, estrogen metabolism, and immunity resulting in the development and progression of endometriosis. In this review, we discuss the diverse mechanisms of endometriosis closely related to the gut microbiota in order to provide new approaches for deeper exploration and expanded investigation for endometriosis on prevention, early diagnosis and treatment.

Lactobacillus induced by irbesartan on spontaneously hypertensive rat contribute to its antihypertensive effect

OBJECTIVE

Hypertension is linked to gut dysbiosis. Here, the impact of the angiotensin receptor antagonist irbesartan on the gut microbiota of spontaneously hypertensive rats (SHR) were investigated. In addition, we assessed their contribution to its antihypertensive effect.

METHODS

Eight-week-old Wistar-Kyoto (WKY) rats and SHR were administered irbesartan for 8 weeks. Fecal microbiota transplantation (FMT) was performed from SHR treated with irbesartan or untreated SHR to recipient untreated SHR. The preventive effect of Lactobacillus on hypertension in SHR was evaluated. Blood pressure (BP) was calculated using a tail-sleeve sphygmomanometer. To better assess the composition of the gut microbiota, the V3-V4 region of the 16S rRNA gene was amplified while short-chain fatty acids (SCFAs) in feces were tested by liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS).

RESULTS

Irbesartan restored gut dysbiosis, increased the abundance of Lactobacillus , and improved anti-inflammatory ability, antioxidative ability, intestinal integrity, and intestinal inflammation in SHR. The microbiota in SHR-treated irbesartan could reduce BP and improve antioxidative ability and gut integrity in SHR. Lactobacillus johnsonii ( L. johnsonii ) and Lactobacillus reuteri ( L. reuteri ) reduced BP, restored gut dysbiosis and improved anti-inflammatory ability, antioxidative ability, intestinal integrity in SHR. Most notably, irbesartan, L. johnsonii , and L. reuteri can significantly increase SCFA content in SHR feces.

CONCLUSION

The current study demonstrated that irbesartan treatment ameliorated gut dysbiosis in SHR. Irbesartan induced alterations in gut microbiota, with increased prevalence of Lactobacillus .

Composition of the gut microbiome, role of diet, lifestyle, and antioxidant therapies in diabetes mellitus and diabetic retinopathy

The gut microbiome is a complex ecosystem in the gastrointestinal tract composed of trillions of bacteria, viruses, fungi, and protozoa. Disruption of this delicate ecosystem, formally called "dysbiosis", has been linked to a variety of metabolic and inflammatory pathologies. Several studies have focused on abnormal microbiome composition and correlated these findings with the development of type 2 diabetes mellitus (T2DM) and diabetic retinopathy (DR). However, given the complexity of this ecosystem, the current studies are narrow in design and present variable findings. Composition of the gut microbiome in patients with DR significantly differs from patients with diabetes without retinopathy as well as from healthy controls. Additionally, the gut microbiome has been shown to modify effects of medication, diet, exercise, and antioxidant use on the development and progression of DR. In this paper, we present a comprehensive review of literature on the effect of oxidative stress, antioxidant therapies, and dysbiosis on DR.

Lactobacillus reuteri derived from horse alleviates Escherichia coli-induced diarrhea by modulating gut microbiota

Diarrhea is a prevalent health issue in farm animals and poses a significant challenge to the progress of animal husbandry. Recent evidence suggested that probiotics can alleviate diarrhea by maintaining gut microbial balance and enhancing the integrity of the intestinal barrier. However, there is a scarcity of studies investigating the efficacy of equine Lactobacillus reuteri in relieving E. coli-induced diarrhea. Hence, this study aimed to examine the potential of equine-derived Lactobacillus reuteri in alleviating E. coli diarrhea from the perspective of gut microbiota. Results demonstrated that supplementation of Lactobacillus reuteri had the potential to alleviate diarrhea induced by E. coli infection and restore the decline of tight junction genes, such as Claudin-1 and ZO-1. Additionally, Lactobacillus reuteri supplementation can restore the expression of inflammatory factors (IL-6, IL-10, TNF-α, and IFN-γ) and reduce colon inflammatory damage. Diversity analysis, based on amplicon sequencing, revealed a significant reduction in the diversity of gut microbiota during E. coli-induced diarrhea. Moreover, there were notable statistical differences in the composition and structure of gut microbiota among the different treatment groups. E. coli could induce gut microbial dysbiosis by decreasing the abundance of beneficial bacteria, including Lactobacillus, Bifidobacterium, Ligilactobacillus, Enterorhabdus, and Lachnospiraceae_UCG_001, in comparison to the control group. Conversely, supplementation with Lactobacillus reuteri could restore the abundance of beneficial bacteria and increase the diversity of the gut microbiota, thereby reshaping gut microbiota. Additionally, we also observed that supplementation with Lactobacillus reuteri alone improved the gut microbial composition and structure. In summary, the findings suggest that Lactobacillus reuteri can alleviate E. coli-induced diarrhea by preserving the integrity of the intestinal barrier and modulating the composition of the gut microbiota. These results not only contribute to understanding of the mechanism underlying the beneficial effects of Lactobacillus reuteri in relieving diarrhea, but also provide valuable insights for the development of probiotic products aimed at alleviating diarrheal diseases.

Intestinal glucose excretion: A potential mechanism for glycemic control

The gut has been increasingly recognized in recent years as a pivotal organ in the maintenance of glucose homeostasis. Specifically, the profound and enduring improvement in glucose metabolism achieved through metabolic surgery to modify the anatomy of the gut has prompted scholars to acknowledge that the most effective strategy for treating type 2 diabetes mellitus (T2DM) involves the gut. The mechanisms underlying the regulation of glucose metabolism by the gut encompass gut hormones, bile acids, intestinal gluconeogenesis, gut microbiota, and signaling interactions between the gut and other organs (liver, brain, adipose, etc.). Recent studies have also revealed a novel phenomenon of glucose lowering through the gut: metabolic surgery and metformin promote the excretion of glucose from the circulation into the intestinal lumen by enterocytes. However, there is still limited understanding regarding the underlying mechanisms of intestinal glucose excretion and its contribution to glycemic control. This article reviews current research on intestinal glucose excretion while focusing on its role in T2DM management as well as potential mechanisms.

Multiomics analysis revealed the mechanism of the anti-diabetic effect of Salecan

Salecan, a natural β-glucan compromising nine residues connected by β-(1 → 3)/α-(1 → 3) glycosidic bonds, is one of the newly approved food ingredients. Salecan has multiple health-improving effects, yet its mechanism against Type 2 diabetes mellitus (T2DM) remains poorly understood. In this study, the hypoglycemic effect and underlying mechanism of Salecan intervention on STZ-induced diabetic model mice were investigated. After 8 weeks of gavage, Salecan attenuated insulin resistance and repaired pancreatic β cells in a dose-dependent manner. In addition, Salecan supplement remodel the structure of the gut microbiota and altered the level of intestinal metabolites. Serum metabolites, especially unsaturated fatty acids, were also affected significantly. In addition, tight junction proteins in the colon and autophagy-related proteins in the pancreas were upregulated. Multiomics analysis indicated that Lactobacillus johnsonii, Muribaculaceae, and Lachnoclostridium were highly associated with fatty acid esters of hydroxy fatty acids (FAHFA) levels in the colon, accordingly enhancing arachidonic acid and linoleic acid in serum, and promoting GLP-1 release in the intestine and insulin secretion in the pancreas, thus relieving insulin resistance and exhibiting hypoglycemic effects. These findings provide a novel understanding of the anti-diabetic effect of Salecan in mice from a molecular perspective, paving the way for the wide use of Salecan.

Mendelian randomization study supports effect of gut microflora on fractures

To investigate the possible causal relationship between intestinal microflora and fractures using Mendelian randomization (MR). A 2-sample MR study of gut microbiota and fractures was conducted using a weighted inverse variance analysis with tests for heterogeneity, horizontal pleiotropy, and sensitivity. A causal association between fracture risk and specific bacterial taxa was identified at various taxonomic levels: 2 (Bacteroidia, P = .0304; Deltaproteobacteria P = .0304) at the class level, 3 (Bacteroidales, P = .0428; Desulfovibrionales, P = .0428; Enterobacteriales, P = .0208) at the order level, 2 (FamilyXI, P = .0304; Enterobacteriaceae P = .0332) at the family level, and 1 (Alistipes, P = .0405) at the genus level. This study revealed a causal relationship between gut microflora and fracture risk, demonstrating that the effect of different flora taxa flora abundance on fracture risk differs. It provides a reference for further studies.

New insights into the interaction between polycystic ovary syndrome and psychiatric disorders: A narrative review

Polycystic ovary syndrome (PCOS) is a prevalent endocrine disease characterized by hyperandrogenism, ovulatory dysfunction, and ovarian polycystic changes, which combines with reproductive problems, metabolic disorders, and psychological disorders to exhibit a far-reaching impact on the physical and mental health of women. We reviewed previous research and discovered that psychiatric disorders are more common in PCOS patients and their children, potentially exacerbating the condition and creating a vicious loop. To understand the reasons, relevant articles were collected following the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines from PubMed, Web of Science, and Cochrane Library, through December 2022. Evidence suggested that PCOS-related clinical manifestations, hyperandrogenism, insulin resistance, obesity, gut dysbiosis, and other variables may increase the risk of psychiatric disorders in patients. In turn, psychiatric disorders may aggravate the pathologic process of PCOS and increase the difficulty of the treatment. We systematically reported the mechanisms underlying the psychiatric disorders-PCOS interactions, intending to provide potential ways to break the vicious cycle and lay the groundwork for future research. However, research on PCOS and psychiatric disorders were still in initial stages, which limited the scope of this review. More studies are needed to further verify our findings.

Targeting the gut microbiota-related metabolites for osteoporosis: The inextricable connection of gut-bone axis

Osteoporosis is a systemic skeletal disease characterized by decreased bone mass, destruction of bone microstructure, raised bone fragility, and enhanced risk of fractures. The correlation between gut microbiota and bone metabolism has gradually become a widespread research hotspot in recent years, and successive studies have revealed that the alterations of gut microbiota and its-related metabolites are related to the occurrence and progression of osteoporosis. Moreover, several emerging studies on the relationship between gut microbiota-related metabolites and bone metabolism are also underway, and extensive research evidence has indicated an inseparable connection between them. Combined with latest literatures and based on inextricable connection of gut-bone axis, this review is aimed to summarize the relation, potential mechanisms, application strategies, clinical application prospects, and existing challenges of gut microbiota and its-related metabolites on osteoporosis, thus updating the knowledge in this research field and providing certain reference for future researches.

Therapeutic applications of gut microbes in cardiometabolic diseases: current state and perspectives

Cardiometabolic disease (CMD) encompasses a range of diseases such as hypertension, atherosclerosis, heart failure, obesity, and type 2 diabetes. Recent findings about CMD's interaction with gut microbiota have broadened our understanding of how diet and nutrition drive microbes to influence CMD. However, the translation of basic research into the clinic has not been smooth, and dietary nutrition and probiotic supplementation have yet to show significant evidence of the therapeutic benefits of CMD. In addition, the published reviews do not suggest the core microbiota or metabolite classes that influence CMD, and systematically elucidate the causal relationship between host disease phenotypes-microbiome. The aim of this review is to highlight the complex interaction of the gut microbiota and their metabolites with CMD progression and to further centralize and conceptualize the mechanisms of action between microbial and host disease phenotypes. We also discuss the potential of targeting modulations of gut microbes and metabolites as new targets for prevention and treatment of CMD, including the use of emerging technologies such as fecal microbiota transplantation and nanomedicine. KEY POINTS: • To highlight the complex interaction of the gut microbiota and their metabolites with CMD progression and to further centralize and conceptualize the mechanisms of action between microbial and host disease phenotypes. • We also discuss the potential of targeting modulations of gut microbes and metabolites as new targets for prevention and treatment of CMD, including the use of emerging technologies such as FMT and nanomedicine. • Our study provides insight into identification-specific microbiomes and metabolites involved in CMD, and microbial-host changes and physiological factors as disease phenotypes develop, which will help to map the microbiome individually and capture pathogenic mechanisms as a whole.

Crosstalk between glucagon-like peptide 1 and gut microbiota in metabolic diseases

Gut microbiota exert influence on gastrointestinal mucosal permeability, bile acid metabolism, short-chain fatty acid synthesis, dietary fiber fermentation, and farnesoid X receptor/Takeda G protein-coupled receptor 5 (TGR5) signal transduction. The incretin glucagon-like peptide 1 (GLP-1) is mainly produced by L cells in the gut and regulates postprandial blood glucose. Changes in gut microbiota composition and function have been observed in obesity and type 2 diabetes (T2D). Meanwhile, the function and rhythm of GLP-1 have also been affected in subjects with obesity or T2D. Therefore, it is necessary to discuss the link between the gut microbiome and GLP-1. In this review, we describe the interaction between GLP-1 and the gut microbiota in metabolic diseases. On the one hand, gut microbiota metabolites stimulate GLP-1 secretion, and gut microbiota affect GLP-1 function and rhythm. On the other hand, the mechanism of action of GLP-1 on gut microbiota involves the inflammatory response. Additionally, we discuss the effects and mechanism of various interventions, such as prebiotics, probiotics, antidiabetic drugs, and bariatric surgery, on the crosstalk between gut microbiota and GLP-1. Finally, we stress that gut microbiota can be used as a target for metabolic diseases, and the clinical application of GLP-1 receptor agonists should be individualized.

Dietary intervention improves metabolic levels in patients with type 2 diabetes through the gut microbiota: a systematic review and meta-analysis

Background

Poor dietary structure plays a pivotal role in the development and progression of type 2 diabetes and is closely associated with dysbiosis of the gut microbiota. Thus, the objective of this systematic review was to assess the impact of dietary interventions on improving gut microbiota and metabolic levels in patients with type 2 diabetes.

Methods

We conducted a systematic review and meta-analysis following the PRISMA 2020 guidelines.

Results

Twelve studies met the inclusion criteria. In comparison to baseline measurements, the high-fiber diet produced substantial reductions in FBG (mean difference -1.15 mmol/L; 95% CI, -2.24 to -0.05; I2 = 94%; P = 0.04), HbA1c (mean difference -0.99%; 95% CI, -1.93 to -0.03; I2 = 89%; P = 0.04), and total cholesterol (mean difference -0.95 mmol/L; 95% CI, -1.57 to -0.33; I2 = 77%; P = 0.003); the high-fat and low-carbohydrate diet led to a significant reduction in HbA1c (mean difference -0.98; 95% CI, -1.50 to -0.46; I2 = 0%; P = 0.0002). Within the experimental group (intervention diets), total cholesterol (mean difference -0.69 mmol/L; 95% CI, -1.27 to -0.10; I2 = 52%; P = 0.02) and LDL-C (mean difference -0.45 mmol/L; 95% CI, -0.68 to -0.22; I2 = 0%; P < 0.0001) experienced significant reductions in comparison to the control group (recommended diets for type 2 diabetes). However, no statistically significant differences emerged in the case of FBG, HbA1c, HOMA-IR, and HDL-C between the experimental and control groups. The high dietary fiber diet triggered an augmented presence of short-chain fatty acid-producing bacteria in the intestines of individuals with T2DM. In addition, the high-fat and low-carbohydrate diet resulted in a notable decrease in Bacteroides abundance while simultaneously increasing the relative abundance of Eubacterium. Compared to a specific dietary pattern, personalized diets appear to result in the production of a greater variety of beneficial bacteria in the gut, leading to more effective blood glucose control in T2D patients.

Conclusion

Dietary interventions hold promise for enhancing metabolic profiles in individuals with T2D through modulation of the gut microbiota. Tailored dietary regimens appear to be more effective than standard diets in improving glucose metabolism. However, given the limited and highly heterogeneous nature of the current sample size, further well-designed and controlled intervention studies are warranted in the future.

Causal relationship of gut microbiota with diabetic nephropathy: a Mendelian randomization analysis

Background

Patients with DN (diabetic nephropathy) show remarkable variations in their gut microbiota composition. However, to date, no study has shown whether a causal relationship exists between gut microbiota composition and DN.

Methods

Here, we performed a two-sample Mendelian randomization (MR) investigation for identifying causal associations of gut microbiota with DN. Gut microbiota genetic data were gathered from the recent genome-wide association study pooled data of the MiBioGen consortium, which included 24 cohorts and 18,340 individuals.

Results

IVW(Inverse variance weighting) revealed that Verrucomicrobia [odds ratio (OR) = 1.390; 95% confidence interval (CI) = 1.10-1.75; p = 0.005], Peptostreptococcaceae (OR = 1.284; 95% CI = 1.03-1.59; p = 0.012), Verrucomicrobiaceae (OR = 1.390; 95% CI = 1.10-1.75; p = 0.005), Akkermansia (OR = 1.390; 95% CI = 1.10-1.75; p = 0.005), Butyricimonas (OR = 1.261; 95% CI = 1.02-1.55; p = 0.031), Catenibacterium (OR = 1.278; 95% CI = 1.02-1.59; p = 0.030).

Conclusion

Two-sample MR analysis identified 12 microbial taxa in gut microbiota (one of which is yet to be officially named) that showed significant causal associations with DN; 8 of these taxa significantly increased the risk of DN, while the remaining 4 taxa (including the one without an official name) reduced the risk of DN. The precise mechanisms influencing the interactions of gut microbiota with DN occurrence remain unclear; hence, additional investigations should be conducted to clarify these mechanisms.

Carboxymethyl chitosan-TK resistant starch complex ameliorates type 2 diabetes by regulating the gut microbiota

Carboxymethyl chitosan and resistant starch exhibit good performance in diabetes regulation. We prepared carboxymethyl chitosan - resistant starch complex. Test the properties of composite resistant starch by using X-ray diffraction, water contact angle, infrared spectroscopy, and scanning electron microscopy, interactions with intestinal microbiota and mouse experiments were also conducted. The results indicated that the composite resistant starch had a good effect on promoting the proliferation of probiotics on Bifidobacterium and a significant inhibitory effect on Escherichia coli than resistant starch (P < 0.05). After administration, the water intake and weight of diabetic mice were significantly reduced. The blood glucose of diabetic mice was also reduced, and oral glucose tolerance showed that the glucose degradation rates of composite resistant starch were significantly improved compared to model mice. Cholesterol, triglycerides, high-density lipoprotein and low-density lipoprotein were significantly lower than those in the diabetes group (P < 0.05). The diversity of the gut microbiota was also proven.

White hyacinth bean polysaccharide ameliorates diabetes via microbiota-gut-brain axis in type 2 diabetes mellitus rats

Gut played a potent role in onset and progression of metabolic disorders, presenting an exciting direction for diabetes prevention. Here, the anti-diabetic effects of White hyacinth bean polysaccharides (WHBP) were observed, including the reduction of blood glucose levels and improvement of intestinal impairment in type 2 diabetes mellitus (T2DM) rats. Further data concerning intestinal protection suggested that WHBP restored intestinal barrier, as evidenced by inhibition of intestinal pathological damage, up-regulation of Zonula occluden-1 expression and manipulation of the redox system in T2DM rats. Moreover, WHBP-mediated anti-diabetic effects were in parallel with the adjustment of changes in gut microbiota composition of T2DM rats. Meanwhile, hypersecretion of corticotropin-releasing hormone, adrenocorticotropic hormone, and corticosterone levels, which were critical coordinators of the hypothalamic-pituitary-adrenal (HPA) axis, were suppressed in T2DM rats exposed to WHBP, indicating that WHBP-mediated health benefits were referring to regulate brain feedback in reduction of HPA axis. Concomitantly, further suggested and expanded on gut-brain communication by data of microbial metabolites short-chain fatty acids, mediators of gut-brain interactions, were remarkably raised in cecum contents of T2DM rats subjected to WHBP. Collectively, WHBP performed anti-diabetic effects were associated with control of microbiota-gut-brain axis implicated in intestinal barrier, HPA axis, gut microbiota and their metabolites.

Application of Metabolomics and Traditional Chinese Medicine for Type 2 Diabetes Mellitus Treatment

Diabetes is a major global public health problem with high incidence and case fatality rates. Traditional Chinese medicine (TCM) is used to help manage Type 2 Diabetes Mellitus (T2DM) and has steadily gained international acceptance. Despite being generally accepted in daily practice, the TCM methods and hypotheses for understanding diseases lack applicability in the current scientific characterization systems. To date, there is no systematic evaluation system for TCM in preventing and treating T2DM. Metabonomics is a powerful tool to predict the level of metabolites in vivo, reveal the potential mechanism, and diagnose the physiological state of patients in time to guide the follow-up intervention of T2DM. Notably, metabolomics is also effective in promoting TCM modernization and advancement in personalized medicine. This review provides updated knowledge on applying metabolomics to TCM syndrome differentiation, diagnosis, biomarker discovery, and treatment of T2DM by TCM. Its application in diabetic complications is discussed. The combination of multi-omics and microbiome to fully elucidate the use of TCM to treat T2DM is further envisioned.

Bridging the Gap from Enterotypes to Personalized Dietary Recommendations: A Metabolomics Perspective on Microbiome Research

Advances in high-throughput DNA sequencing have propelled research into the human microbiome and its link to metabolic health. We explore microbiome analysis methods, specifically emphasizing metabolomics, how dietary choices impact the production of microbial metabolites, providing an overview of studies examining the connection between enterotypes and diet, and thus, improvement of personalized dietary recommendations. Acetate, propionate, and butyrate constitute more than 95% of the collective pool of short-chain fatty acids. Conflicting data on acetate's effects may result from its dynamic signaling, which can vary depending on physiological conditions and metabolic phenotypes. Human studies suggest that propionate has overall anti-obesity effects due to its well-documented chemistry, cellular signaling mechanisms, and various clinical benefits. Butyrate, similar to propionate, has the ability to reduce obesity by stimulating the release of appetite-suppressing hormones and promoting the synthesis of leptin. Tryptophan affects systemic hormone secretion, with indole stimulating the release of GLP-1, which impacts insulin secretion, appetite suppression, and gastric emptying. Bile acids, synthesized from cholesterol in the liver and subsequently modified by gut bacteria, play an essential role in the digestion and absorption of dietary fats and fat-soluble vitamins, but they also interact directly with intestinal microbiota and their metabolites. One study using statistical methods identified primarily two groupings of enterotypes Bacteroides and Ruminococcus. The Prevotella-dominated enterotype, P-type, in humans correlates with vegetarians, high-fiber and carbohydrate-rich diets, and traditional diets. Conversely, individuals who consume diets rich in animal fats and proteins, typical in Western-style diets, often exhibit the Bacteroides-dominated, B-type, enterotype. The P-type showcases efficient hydrolytic enzymes for plant fiber degradation but has limited lipid and protein fermentation capacity. Conversely, the B-type features specialized enzymes tailored for the degradation of animal-derived carbohydrates and proteins, showcasing an enhanced saccharolytic and proteolytic potential. Generally, models excel at predictions but often struggle to fully elucidate why certain substances yield varied responses. These studies provide valuable insights into the potential for personalized dietary recommendations based on enterotypes.

Poricoic acid A induces mitophagy to ameliorate podocyte injury in diabetic kidney disease via downregulating FUNDC1

Diabetic kidney disease (DKD) is a devastating complication of diabetes mellitus (DM) and is the most prevalent chronic kidney disease (CKD). Poricoic acid A (PAA), a component isolated from Traditional Chinese Medicine (TCM) Poria cocos, has hypoglycaemic and anti-fibrosis effects. However, the role of PAA in DKD remains largely unclear. To mimics an in vitro model of DKD, the mouse podocyte MPC5 cells were treated with high glucose (25 mM; HG) for 24 h. CCK-8 and flow cytometry assays were conducted for assessing MPC5 cell viability and apoptosis. Meanwhile, streptozotocin (STZ) was used to induce experimental DKD in mice by intraperitoneal injection. PAA notably inhibited the apoptosis and inflammation, reduced the generation of ROS, and elevated the MMP level in HG-treated MPC5 cells. Moreover, PAA obviously reduced blood glucose and urine protein levels, inhibited renal fibrosis in DKD mice. Meanwhile, PAA markedly increased LC3 and ATG5 levels and declined p62 and FUNDC1 levels in HG-treated MPC5 cells and in the kidney tissues of DKD mice, leading to the activation of cell mitophagy. Furthermore, the downregulation of FUNDC1 also inhibited apoptosis, inflammation, and promoted mitophagy in HG-treated MPC5 cells. As expected, the knockdown of FUNDC1 further enhanced the protective role of PAA in MPC5 cells following HG treatment, indicating that induction of mitophagy could attenuate podocyte injury. Collectively, PAA could exert beneficial effects on podocyte injury in DKD by promoting mitophagy via downregulating FUNDC1. These findings suggested that PAA may have great potential in alleviating kidney injury in DKD.

Sanziguben polysaccharides improve diabetic nephropathy in mice by regulating gut microbiota to inhibit the TLR4/NF-κB/NLRP3 signalling pathway

CONTEXT

Sanziguben (SZGB) is an empirical prescription used in traditional Chinese medicine to treat diabetic nephropathy (DN). As an abundant and primarily effective component of SZGB, Sanziguben polysaccharides (SZP) can be digested by flora to generate biological activity.

OBJECTIVE

Our study aimed to clarify the potential mechanism of SZP in improving chronic DN.

MATERIALS AND METHODS

Male db/db mice were randomized into DN, SZP (500 mg/kg) and metformin (MET, 300 mg/kg) groups. Wild-type littermates served as the normal control (NC) group. The drug was orally administered for 8 weeks. Enzyme-linked immunosorbent assay was used to detect the inflammatory factors. Proteins related to inflammation were evaluated using western blotting and immunohistochemical examination. Gut microbiota was analysed using 16S rRNA sequencing.

RESULTS

SZP significantly reduced 24 h urine albumin (p < 0.05) of DN mice. Compared to DN group, SZP significantly decreased the homeostasis model assessment of insulin resistance index, serum creatinine and blood urea nitrogen levels (20.27 ± 3.50 vs. 33.64 ± 4.85, 19.22 ± 3.77 vs. 32.52 ± 3.05 μmol/L, 13.23 ± 1.42 vs. 16.27 ± 0.77 mmol/L, respectively), and mitigated renal damage. SZP also regulated gut microbiota and decreased the abundance of Gram-negative bacteria (Proteobacteria, Klebsiella and Escherichia-Shigella). Subsequently, SZP reduced lipopolysaccharides levels (1.06- to 1.93-fold) of DN mice. Furthermore, SZP inhibited the expression levels of TLR4, phospho-NF-κB p65, NLRP3 proteins and interleukin (IL)-18 and IL-1β.

CONCLUSIONS

These results demonstrated that SZP improved intestinal flora disorder and inhibited the TLR4/NF-κB/NLRP3 pathway to alleviate DN.

Total Astragalus saponins can reverse type 2 diabetes mellitus-related intestinal dysbiosis and hepatic insulin resistance in vivo

Objective

Intestinal flora homeostasis in rats with type 2 diabetes mellitus (T2DM) was evaluated to explore the effects of total Astragalus saponins (TAS) on hepatic insulin resistance (IR).

Methods

Six-week-old male Sprague-Dawley rats were fed high-fat and high-sugar diet for 4 weeks and intraperitoneally injected with streptozotocin to induce T2DM, and they were then randomly divided into control, model, metformin, and TAS groups. Stool, serum, colon, and liver samples were collected after 8 weeks of drug administration for relevant analyses.

Results

TAS reduced fasting blood glucose, 2-hour postprandial blood glucose, area under the curve of oral glucose tolerance test, glycated serum protein, homeostasis model assessment of insulin resistance, total cholesterol, triglyceride, and low-density lipoprotein cholesterol levels in T2DM rats but increased insulin, C-peptide, and high-density lipoprotein cholesterol levels. Moreover, TAS improved the morphology and structure of liver and colon tissues and improved the composition of the intestinal microbiome and bacterial community structure at different taxonomic levels. In addition, TAS increased the protein expression of hepatic IRS-1, PI3K, PDK1, and p-AKT and decreased the protein expression of p-GSK-3β. Meanwhile, TAS increased the mRNA expression of liver PDK1, PI3K, and GS and decreased the mRNA expression of GSK-3β.

Conclusion

TAS can ameliorate T2DM-related abnormal glucose and blood lipid metabolism, intestinal dysbiosis, and IR.

Integrated Gut Microbiota and Urine Metabolite Analyses of T2DM with NAFLD Rat Model

Globally 80% type 2 diabetes mellitus (T2DM) patients suffer nonalcoholic fatty liver disease (NAFLD). The interplay of gut microbiota and endogenous metabolic networks has not yet been reported in the setting of T2DM with NAFLD. As such, this study utilized 16S rRNA gene sequencing to assess the changes in intestinal flora and nuclear magnetic resonance spectroscopy (1H NMR) to identify potential metabolites in a T2DM with NAFLD rat model. Spearman correlation analysis was performed to explore the relationship between gut microbiota and metabolites. Results revealed that among T2DM with NAFLD rats, diversity indexes of intestinal microbiota were distinctly decreased while levels of 18 bacterial genera within the intestinal tract were significantly altered. In addition, levels of eight metabolites mainly involved in the synthesis and degradation of ketone bodies, the TCA cycle, and butanoate metabolism were altered. Correlation analysis revealed that gut bacteria such as Blautia, Ruminococcus torques group, Allobaculum, and Lachnoclostridium strongly associate with 3-hydroxybutyrate, acetone, acetoacetate, 2-oxoglutarate, citrate, creatinine, hippurate, and allantoin. Our findings can provide a basis for future development of targeted treatments.

Dityrosine Aggravates Hepatic Insulin Resistance in Obese Mice by Altering Gut Microbiota and the LPS/TLR4/NF-κB Inflammatory Pathway

SCOPE

Dityrosine is the main product of protein oxidation, which has been proved to be a threat to human health. This study aims to investigate whether dityrosine exacerbates insulin resistance by inducing gut flora disturbance and associated inflammatory responses.

METHODS AND RESULTS

Mice fed with normal diet or high-fat diet (HFD) received daily gavage of dityrosine (320 µg kg-1 BW) or saline for consecutive 13 weeks. The effects of dityrosine on gut microbiota are verified by in vitro fermentation using fecal microbiota from db/m mice and db/db mice. As a result, dityrosine causes the insulin resistance in mice fed normal diet, and aggravates the effects of HFD on insulin sensitivity. Dityrosine increases the levels of lipopolysaccharide (LPS), lipopolysaccharide-binding protein (LBP), toll-like receptor 4 (TLR4), nuclear factor kappa-B (NF-κB), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and interleukin-8 (IL-8) but decreases levels of interleukin-10 (IL-10) in the plasma of CON and HFD-fed mice. The changes of gut flora composition caused by dityrosine are significantly correlated with the changes of inflammatory biomarkers.

CONCLUSION

The effects of dityrosine on insulin resistance may be attributed to the reshaping of the gut microbiota composition and promoting the activity of the LPS/TLR4/NF-κB inflammatory pathway in HFD-induced obese individuals.

The intellectual base and global trends in inflammation of diabetic kidney disease: a bibliometric analysis

Diabetic kidney disease (DKD) is a severe complication of diabetes mellitus (DM). The literature on DKD inflammation research has experienced substantial growth. However, there is a lack of bibliometric analyses. This study aimed to examine the existing research on inflammation in DKD by analyzing articles published in the Web of Science Core Collection (WOSCC) over the past 30 years. We conducted a visualization analysis using several software, including CiteSpace and VOSviewer. We found that the literature on inflammation research in DKD has experienced substantial growth, indicating a rising interest in this developing area of study. In this field, Navarro-Gonzalez, JF is the most frequently cited author, Kidney International is the most frequently cited journal, China had the highest number of publications in the field of DKD inflammation, and Monash University emerged as the institution with the most published research. The research area on inflammation in DKD primarily centers around the investigation of 'Glycation end-products', 'chronic kidney disease', and 'diabetic nephropathy'. The emerging research trends in this field will focus on the 'Gut microbiota', 'NLRP3 inflammasome', 'autophagy', 'pyroptosis', 'sglt2 inhibitor', and 'therapeutic target'. Future research on DKD may focus on further exploring the inflammatory response, identifying specific therapeutic targets, studying biomarkers, investigating stem cell therapy and tissue engineering, and exploring gene therapy and gene editing. In summary, this study examines the main areas of study, frontiers, and trends in DKD inflammation, which have significant implications for future research.

A Metabolite Perspective on the Involvement of the Gut Microbiota in Type 2 Diabetes

Type 2 diabetes (T2D) is a commonly diagnosed condition that has been extensively studied. The composition and activity of gut microbes, as well as the metabolites they produce (such as short-chain fatty acids, lipopolysaccharides, trimethylamine N-oxide, and bile acids) can significantly impact diabetes development. Treatment options, including medication, can enhance the gut microbiome and its metabolites, and even reverse intestinal epithelial dysfunction. Both animal and human studies have demonstrated the role of microbiota metabolites in influencing diabetes, as well as their complex chemical interactions with signaling molecules. This article focuses on the importance of microbiota metabolites in type 2 diabetes and provides an overview of various pharmacological and dietary components that can serve as therapeutic tools for reducing the risk of developing diabetes. A deeper understanding of the link between gut microbial metabolites and T2D will enhance our knowledge of the disease and may offer new treatment approaches. Although many animal studies have investigated the palliative and attenuating effects of gut microbial metabolites on T2D, few have established a complete cure. Therefore, conducting more systematic studies in the future is necessary.

Type 1 and Type 2 Diabetes Mellitus: Commonalities, Differences and the Importance of Exercise and Nutrition

Diabetes mellitus represents a group of physiological dysfunctions characterized by hyperglycaemia resulting directly from insulin resistance (in the case of type 2 diabetes mellitus-T2DM), inadequate insulin secretion/production, or excessive glucagon secretion (in type 1 diabetes mellitus-T1DM) [...].

The characteristics of intestinal microbiota in patients with chronic schistosomiasis japonica-induced liver fibrosis by 16S rRNA gene sequence

Background

The intestinal microbiota is known to play a role in the development of liver disease, there is a limited understanding of the intestinal microbiota associated with chronic schistosomiasis japonica. This study sought to explore the characteristics of the intestinal microbiota in patients with chronic schistosomiasis japonica and identify potential biomarkers that could aid diagnosis.

Methods

A total of 40 residents of Qingshan Island in Yueyang (Hunan, China) were enrolled in this cross-sectional study. These individuals were divided into two groups for analysis of the intestinal microbiota: patients with chronic schistosomiasis japonica-induced liver fibrosis group (CSJ group, n = 10) and a healthy control group (HC group, n = 30). Feces were collected from each participant and analyzed by 16S rRNA gene sequencing, which included species composition analysis at the phylum and family levels, α and β diversity analysis, LEfSe, Kyoto Encyclopedia of Genes and Genome (KEGG) and Clusters of Orthologous Groups of proteins (COG) analysis.

Results

Our results indicated that Schistosoma japonicum infection changed the composition and abundance of intestinal microbiota at the phylum and family levels. Compared with the HC group, the α and β diversity results showed that CSJ group had low diversity of species of the intestinal microbiome. LEfSe and relative abundance analysis found that the Prevotella 7, Alloprevotella, and Holdemanella genera were significantly higher in the CSJ group than in the HC group. Meanwhile, the ROC analysis showed that the area under the curve (AUC) of Prevotella 7, Alloprevotella, and Holdemanella genera was 0.779, 0.769, and 0.840, respectively. KEGG and COG analysis showed that the Replication and Repair, and Defense Mechanism pathways correlated strongly with chronic schistosomiasis japonica infection.

Conclusion

The current study was the first to explore differences in the intestinal microbiota of patients with chronic schistosomiasis japonica-induced liver fibrosis and healthy people from Qingshan Island, which indicated that Prevotella 7, Alloprevotella, and Holdemanella genera could have a potential value in non-invasive diagnosis of chronic schistosomiasis japonica-induced fibrosis.

Gut microbiota: A magical multifunctional target regulated by medicine food homology species

BACKGROUND

The relationship between gut microbiota and human health has gradually been recognized. Increasing studies show that the disorder of gut microbiota is related to the occurrence and development of many diseases. Metabolites produced by the gut microbiota are responsible for their extensive regulatory roles. In addition, naturally derived medicine food homology species with low toxicity and high efficiency have been clearly defined owing to their outstanding physiological and pharmacological properties in disease prevention and treatment.

AIM OF REVIEW

Based on supporting evidence, the current review summarizes the representative work of medicine food homology species targeting the gut microbiota to regulate host pathophysiology and discusses the challenges and prospects in this field. It aims to facilitate the understanding of the relationship among medicine food homology species, gut microbiota, and human health and further stimulate the advancement of more relevant research.

KEY SCIENTIFIC CONCEPTS OF REVIEW

As this review reveals, from the initial practical application to more mechanism studies, the relationship among medicine food homology species, gut microbiota, and human health has evolved into an irrefutable interaction. On the one hand, through affecting the population structure, metabolism, and function of gut microbiota, medicine food homology species maintain the homeostasis of the intestinal microenvironment and human health by affecting the population structure, metabolism, and function of gut microbiota. On the other hand, the gut microbiota is also involved in the bioconversion of the active ingredients from medicine food homology species and thus influences their physiological and pharmacological properties.

Gut Microbiota Combined with Serum Metabolomics to Investigate the Hypoglycemic Effect of Actinidia arguta Leaves

Actinidia arguta leaves (AAL) are an excellent source of bioactive components for the food industry and possess many functional properties. However, the hypoglycemic effect and mechanism of AAL remain unclear. The aim of this work was to investigate the potential hypoglycemic effect of AAL and explore its possible mechanism using 16S rRNA sequencing and serum metabolomics in diabetic mice induced by high-fat feeding in combination with streptozotocin injection. A total of 25 flavonoids from AAL were isolated and characterized, and the contents of the extract from the AAL ranged from 0.14 mg/g DW to 8.97 mg/g DW. The compound quercetin (2) had the highest content of 8.97 ± 0.09 mg/g DW, and the compound kaempferol-3-O-(2'-O-D-glucopyl)-β-D-rutinoside (12) had the lowest content of 0.14 ± 0.01 mg/g DW. In vivo experimental studies showed that AAL reduced blood glucose and cholesterol levels, improved insulin sensitivity, and ameliorated oxidative stress and liver and kidney pathological damage. In addition, gut microbiota analysis found that AAL significantly reduced the F/B ratio, enriched the beneficial bacteria Bacteroides and Bifidobacterium, and inhibited the harmful bacteria Lactobacillus and Desulfovibrio, thereby playing an active role in intestinal imbalance. In addition, metabolomics analysis showed that AAL could improve amino acid metabolism and arachidonic acid metabolism, thereby exerting a hypoglycemic effect. This study confirmed that AAL can alleviate type 2 diabetes mellitus (T2DM) by regulating intestinal flora and interfering with related metabolic pathways, providing a scientific basis for its use as a dietary supplement and for further exploration of the mechanism of AAL against T2DM.

Advances in Research on Type 2 Diabetes Mellitus Targets and Therapeutic Agents

Diabetes mellitus is a chronic multifaceted disease with multiple potential complications, the treatment of which can only delay and prolong the terminal stage of the disease, i.e., type 2 diabetes mellitus (T2DM). The World Health Organization predicts that diabetes will be the seventh leading cause of death by 2030. Although many antidiabetic medicines have been successfully developed in recent years, such as GLP-1 receptor agonists and SGLT-2 inhibitors, single-target drugs are gradually failing to meet the therapeutic requirements owing to the individual variability, diversity of pathogenesis, and organismal resistance. Therefore, there remains a need to investigate the pathogenesis of T2DM in more depth, identify multiple therapeutic targets, and provide improved glycemic control solutions. This review presents an overview of the mechanisms of action and the development of the latest therapeutic agents targeting T2DM in recent years. It also discusses emerging target-based therapies and new potential therapeutic targets that have emerged within the last three years. The aim of our review is to provide a theoretical basis for further advancement in targeted therapies for T2DM.

Cross-seeding enables repurposing of aurein antimicrobial peptides as a promoter of human islet amyloid polypeptide (hIAPP)

Since hIAPP (human islet amyloid polypeptide) aggregation and microbial infection are recognized as significant risk factors that contribute to the pathogenesis of type II diabetes (T2D), targeting these catastrophic processes simultaneously may have a greater impact on the prevention and treatment of T2D. Different from the well-studied hIAPP inhibitors, here we propose and demonstrate a repurposing strategy for an antimicrobial peptide, aurein, which can simultaneously modulate hIAPP aggregation and inhibit microbial infection. Collective data from protein, cell, and bacteria assays revealed multiple functions of aurein including (i) promotion of hIAPP aggregation at a low molar ratio of aurein:hIAPP = 0.5 : 1-2 : 1, (ii) reduction of hIAPP-induced cytotoxicity in RIN-m5F cells, and (iii) preservation of original antimicrobial activity against E. coli., S.A., and S.E. strains in the presence of hIAPP. These functions of aurein are mainly derived from its strong binding to different hIAPP seeds through conformationally similar β-sheet association. Our study provides a promising avenue for the repurposing of antimicrobial peptides (such as aurein) as amyloid modulators for blocking at least two pathological pathways in T2D.

Protective effects and mechanisms of opuntia polysaccharide in animal models of diabetes mellitus: A systematic review and meta-analysis

ETHNOPHARMACOLOGICAL RELEVANCE

Opuntia speciesis used in traditional medicine to treat diabetes mellitus (DM). Polysaccharide is one of the main components of Opuntia. Opuntia polysaccharide (OPS) is a kind of natural active macromolecular substance, numerous animal experiments have been conducted to treat DM, however, its protective effect and mechanism in animal models of DM has not been clarified.

AIM OF THE STUDY

The aim of this study is to evaluate the efficacy of OPS on DM through a stematic review and meta-analysis of animal models, and whether its improves blood glucose (BG) levels, body weight (BW), food intake, water intake, and lipid levels, and to summarize the potential mechanism of OPS in the treatment of DM.

MATERIALS AND METHODS

We searched relevant Chinese and English databases from the date of construction to March 2022, including PubMed (MEDLINE), Embase, Cochrane Library, Scopus and Web of Science, China National Knowledge Infrastructure (CNKI), Chinese Biomedicine Literature Database (CBM), Chinese Science and Technology Periodicals Database (VIP), Wanfang Database. 16 studies were included for meta-analysis.

RESULTS

The results showed that compared with the model group, the OPS significantly improved BG, BW, food intake, water intake, total cholesterol (TC), triglycerides (TG), high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C). Meta-regression and subgroup analysis showed that intervention dose, animal species, duration and modeling method may be the source of the heterogeneity. There was no statistical difference between the positive control group and the OPS treatment group in improving BW, food intake, water intake, TC, TG, HDL-C, and LDL-C.

CONCLUSIONS

OPS can effectively improve the symptoms of hyperglycemia, polydipsia, polyphagia, low body weight, and dyslipidemia in DM animals. The possible protective mechanisms of OPS on DM animals are immune regulation, repair of damaged pancreatic β cells, and inhibition of oxidative stress and cell apoptosis.

Gut microbiota and eye diseases: a bibliometric study and visualization analysis

Introduction

Recently the role of gut microbial dysbiosis in many ocular disorders, including but not limited to uveitis, age-related macular degeneration (AMD), diabetic retinopathy (DR), dry eye, keratitis and orbitopathy is a hot research topic in the field. Targeting gut microbiota to treat these diseases has become an unstoppable trend. Bibliometric study and visualization analysis have become essential methods for literature analysis in the medical research field. We aim to depict this area's research hotspots and future directions by bibliometric software and methods.

Methods

We search all the related publications from the Web of Science Core Collection. Then, CiteSpace was applied to analyze and visualize the country distributions, dual-map overlay of journals, keyword bursts, and co-cited references. VOSviewer was employed to identify authors, co-cited authors, journals and co-cited journals and display the keyword co-occurrence networks.

Results

A total of 284 relevant publications were identified from 2009 to 2023. The number of studies has been small in the first five years and has grown steadily since 2016. These studies were completed by 1,376 authors from 41 countries worldwide, with the United States in the lead. Lin P has published the most papers while Horai R is the most co-cited author. The top journal and co-cited journal are both Investigative Ophthalmology & Visual Science. In the keyword co-occurrence network, except gut microbiota, inflammation becomes the keyword with the highest frequency. Co-citation analyses reveal that gut dysbiosis is involved in common immune- and inflammation-mediated eye diseases, including uveitis, diabetic retinopathy, age-related macular degeneration, dry eye, and Graves' orbitopathy, and the study of microbiomes is no longer limited to the bacterial populations. Therapeutic strategies that target the gut microbiota, such as probiotics, healthy diet patterns, and fecal microbial transplantation, are effective and critical to future research.

Conclusions

In conclusion, the bibliometric analysis displays the research hotspots and developmental directions of the involvement of gut microbiota in the pathogenesis and treatment of some ocular diseases. It provides an overview of this field's dynamic evolution and structural relationships.

Effect of a 12-Week Polyphenol Rutin Intervention on Markers of Pancreatic β-Cell Function and Gut Microbiota in Adults with Overweight without Diabetes

Supplementation with prebiotic polyphenol rutin is a potential dietary therapy for type 2 diabetes prevention in adults with obesity, based on previous glycaemic improvement in transgenic mouse models. Gut microbiota are hypothesised to underpin these effects. We investigated the effect of rutin supplementation on pancreatic β-cell function measured as C-peptide/glucose ratio, and 16S rRNA gene-based gut microbiota profiles, in a cohort of individuals with overweight plus normoglycaemia or prediabetes. Eighty-seven participants were enrolled, aged 18-65 years with BMI of 23-35 kg/m2. This was a 12-week double-blind randomised controlled trial (RCT), with 3 treatments comprising (i) placebo control, (ii) 500 mg/day encapsulated rutin, and (iii) 500 mg/day rutin-supplemented yoghurt. A 2-h oral glucose tolerance test (OGTT) was performed at baseline and at the end of the trial, with faecal samples also collected. Compliance with treatment was high (~90%), but rutin in both capsule and dietary format did not alter pancreatic β-cell response to OGTT over 12 weeks. Gut bacterial community composition also did not significantly change, with Firmicutes dominating irrespective of treatment. Fasting plasma glucose negatively correlated with the abundance of the butyrate producer Roseburia inulinivorans, known for its anti-inflammatory capacity. This is the first RCT to investigate postprandial pancreatic β-cell function in response to rutin supplementation.

Association of sleep behaviors, insulin resistance surrogates, and the risk of hypertension in Chinese adults with type 2 diabetes mellitus

Objective

Our aim was to evaluate the association between midday napping, combined sleep quality, and insulin resistance surrogates and the risk of hypertension in patients with type 2 diabetes mellitus (T2DM).

Methods

Data were collected using a standardized questionnaire. Binary logistic regression was performed to estimate the odds ratio (OR) and 95% confidence interval (CI) for the risk of hypertension. Systolic and diastolic blood pressure were grouped as categorical variables and unpaired two-sided Student's t-test and Spearman correlation analysis were performed to estimate the association between different blood pressure levels and insulin resistance surrogates.

Results

The overall prevalence rate of hypertension was 50%. Age (OR = 1.056, 95% CI:1.044-1.068), poor sleep quality (OR = 1.959, 95% CI:1.393-2.755), hyperlipidemia (OR = 1.821, 95% CI:1.462-2.369), family history of hypertension (OR = 2.811, 95% CI:2.261-3.495), and obesity (OR = 5.515, 95% CI:1.384-21.971) were significantly associated with an increased risk of hypertension. Midday napping for 1-30 min was negatively correlated with the risk of hypertension (OR = 0.534, 95% CI:0.305-0.936, P <0.05).

Conclusion

Poor sleep quality and obesity are independent risk factors for hypertension. Midday napping (1-30 min) is associated with a decreased risk of hypertension in patients with T2DM.

Probiotics treatment ameliorated mycophenolic acid-induced colitis by enhancing intestinal barrier function and improving intestinal microbiota dysbiosis in mice

Background

Mycophenolic acid (MPA)-induced colitis was still a severe side effect and challenge faced by solid transplant recipients. We aimed to explore the function and mechanism of probiotics in the treatment of MPA-induced colitis.

Methods

In this study, 15 mice (C57BL/6) were randomly assigned into three groups: control (CNTL) group (n = 5), MPA group (n = 5) and the MPA + Probiotic group (n = 5). Bifid Triple Viable capsules, which were drugs for clinical use and consisted of Bifidobacterium longum, Lactobacillus acidophilus, and Enterococcus faecalis, were used in Probiotic group. Body weight change, stool scores, colon histopathology and morphology were used to evaluate the disease severity. The intestinal mucosal barrier function was assessed by measuring the expression level of secretory immunoglobulin A (sIgA), Zonula occludens-1 (ZO-1) and Occludin. Finally, 16S rDNA sequencing and bioinformatics analysis were performed on mice feces to compare the different intestinal microbial composition and diversity among three groups.

Results

Compared with the CNTL group, the mice in MPA group showed a significantly decreased body weight, increased stool scores, shortened colon length and severe colon inflammation. However, probiotics treated MPA mice reversed the disease severity, indicating that probiotics ameliorated MPA-induced colitis in mice. Mechanistically, probiotics improved the intestinal barrier function by up-regulating the expression of sIgA, ZO-1 and Occludin. Moreover, MPA-induced colitis led to intestinal microbiota dysbiosis, including the change of Firmicutes/Bacteroidetes ratio, α- and β-diversity. But probiotic treated group showed mild change in these microbial features. Additionally, we found that Clostridiales was the most significantly different microbiota flora in MPA group.

Conclusion

Probiotics treatment ameliorated MPA-induced colitis by enhancing intestinal barrier function and improving intestinal microbiota dysbiosis. Clostridiales might be the dominant functional intestinal microflora and serve as the potential therapy target in MPA-induced colitis.

Antibiotic-induced gut microbiota dysbiosis has a functional impact on purine metabolism

BACKGROUND

Dysbiosis of the gut microbiota is closely linked to hyperuricemia. However, the effect of the microbiome on uric acid (UA) metabolism remains unclear. This study aimed to explore the mechanisms through which microbiomes affect UA metabolism with the hypothesis that modifying the intestinal microbiota influences the development of hyperuricemia.

RESULTS

We proposed combining an antibiotic strategy with protein-protein interaction analysis to test this hypothesis. The data demonstrated that antibiotics altered the composition of gut microbiota as UA increased, and that the spectrum of the antibiotic was connected to the purine salvage pathway. The antibiotic-elevated UA concentration was dependent on the increase in microbiomes that code for the proteins involved in purine metabolism, and was paralleled by the depletion of bacteria-coding enzymes required for the purine salvage pathway. On the contrary, the microbiota with abundant purine salvage proteins decreased hyperuricemia. We also found that the antibiotic-increased microbiota coincided with a higher relative abundance of bacteria in hyperuricemia mice.

CONCLUSIONS

An antibiotic strategy combined with the prediction of microbiome bacterial function presents a feasible method for defining the key bacteria involved in hyperuricemia. Our investigations discovered that the core microbiomes of hyperuricemia may be related to the gut microbiota that enriches purine metabolism related-proteins. However, the bacteria that enrich the purine salvage-proteins may be a probiotic for decreasing urate, and are more likely to be killed by antibiotics. Therefore, the purine salvage pathway may be a potential target for the treatment of both hyperuricemia and antibiotic resistance.

The gut-retina axis: a new perspective in the prevention and treatment of diabetic retinopathy

Diabetic retinopathy (DR) is a microvascular lesion that occurs as a complication of diabetes mellitus. Many studies reveal that retinal neurodegeneration occurs early in its pathogenesis, and abnormal retinal function can occur in patients without any signs of microvascular abnormalities. The gut microbiota is a large, diverse colony of microorganisms that colonize the human intestine. Studies indicated that the gut microbiota is involved in the pathophysiological processes of DR and plays an important role in its development. On the one hand, numerous studies demonstrated the involvement of gut microbiota in retinal neurodegeneration. On the other hand, alterations in gut bacteria in RD patients can cause or exacerbate DR. The present review aims to underline the critical relationship between gut microbiota and DR. After a brief overview of the composition, function, and essential role of the gut microbiota in ocular health, and the review explores the concept of the gut-retina axis and the conditions of the gut-retina axis crosstalk. Because gut dysbiosis has been associated with DR, the review intends to determine changes in the gut microbiome in DR, the hypothesized mechanisms linking to the gut-retina axis, and its predictive potential.

The role of microbial metabolites in diabetic kidney disease

Background

Growing evidence suggests a complex bidirectional interaction between gut microbes, gut-derived microbial metabolites, and diabetic kidney disease (DKD), known as the "gut-kidney axis" theory. The present study aimed to characterize the role of microbial metabolites in DKD.

Methods

Six-week-old db/db and littermate db/m mice were raised to 20 weeks old. The serum, urine, feces, liver, perinephric fat, and kidney were analyzed using liquid chromatography with tandem mass spectrometry (LC-MS/MS)-based metabolomic analyses.

Results

The db/db mice showed obvious pathological changes and worse renal functions than db/m mice. Indoleacetaldehyde (IAld) and 5-hydroxy-l-tryptophan (5-HTP) in kidney samples, and serotonin (5-HT) in fecal samples were increased in the db/db group. Phosphatidylcholine (PC), phosphatidate (PA), and 1-acylglycerophosphocholine (lysoPC) were decreased in liver and serum samples of the db/db group, while PC and lysoPC were decreased in kidney and perinephric fat samples. Suggested metabolomic homeostasis was disrupted in DKD mice, especially glycerophospholipid and tryptophan metabolism, which are closely related to the gut microbiome.

Conclusions

Our findings reveal the perturbation of gut microbial metabolism in db/db mice with DKD, which may be useful for building a bridge between the gut microbiota and the progression of DKD and provide a theoretical basis for the intestinal treatment of DKD.

Striking a gut-liver balance for the antidiabetic effects of metformin

Metformin is the most prescribed drug for the treatment of type 2 diabetes mellitus (T2DM), but its mechanism of action has not yet been completely elucidated. Classically, the liver has been considered the major site of action of metformin. However, over the past few years, advances have unveiled the gut as an additional important target of metformin, which contributes to its glucose-lowering effect through new mechanisms of action. A better understanding of the mechanistic details of metformin action in the gut and the liver and its relevance in patients remains the challenge of present and future research and may impact drug development for the treatment of T2DM. Here, we offer a critical analysis of the current status of metformin-driven multiorgan glucose-lowering effects.