The Gut Microbiota in Prediabetes and Diabetes: A Population-Based Cross-Sectional Study

Impact of gut microbiota in chronic kidney disease: natural polyphenols as beneficial regulators

Chronic kidney disease (CKD) poses a severe health risk with high morbidity and mortality, profoundly affecting patient quality of life and survival. Despite advancements in research, the pathophysiology of CKD remains incompletely understood. Growing evidence links CKD with shifts in gut microbiota function and composition. Natural compounds, particularly polyphenols, have shown promise in CKD treatment due to their antioxidant and anti-inflammatory properties and their ability to modulate gut microbiota. This review discusses recent progress in uncovering the connections between gut microbiota and CKD, including microbiota changes across different kidney diseases. We also examine metabolite alterations,such as trimethylamine-N-oxide, tryptophan derivatives, branched-chain amino acids, short-chain fatty acids, and bile acids,which contribute to CKD progression. Further, we outline the mechanisms through which polyphenols exert therapeutic effects on CKD, focusing on signaling pathways like nuclear factor kappa-B (NF-κB), mitogen-activated protein kinase (MAPK), mammalian target of rapamycin (mTOR), NOD-like receptor thermal protein domain associated protein 3 (NLRP3), phosphatidylin-ositol-3-kinase (PI3K)/protein kinase B (Akt), and toll like receptors (TLR), as well as their impact on gut microbiota. Lastly, we consider how dietary polyphenols could be harnessed as bioactive drugs to slow CKD progression. Future research should prioritize multi-omics approaches to identify patients who would benefit from polyphenolic interventions, enabling personalized treatment strategies to enhance therapeutic efficacy.

Distinct gut microbiota and metabolome features of tissue-specific insulin resistance in overweight and obesity

Insulin resistance (IR) is an early marker of cardiometabolic deterioration which may develop heterogeneously in key metabolic organs, including the liver (LIR) and skeletal muscle (MIR). This tissue-specific IR is characterized by distinct metabolic signatures, but the role of the gut microbiota in its etiology remains unclear. Here, we profiled the gut microbiota, its metabolites and the plasma metabolome in individuals with either a LIR or MIR phenotype (n = 233). We observed distinct microbial community structures LIR and MIR, and higher short-chain fatty acid (SCFA) producing bacteria, fecal SCFAs and branched-chain fatty acids and a higher postprandial plasma glucagon-like-peptide-1 response in LIR. In addition, we found variations in metabolome profiles and phenotype-specific associations between microbial taxa and functional metabolite groups. Overall, our study highlights association between gut microbiota and its metabolites composition with IR heterogeneity that can be targeted in precision-based strategies to improve cardiometabolic health. Clinicaltrials.gov registration: NCT03708419.

Gut microbiota-driven BCAA biosynthesis via Staphylococcus aureus -expressed acetolactate synthase impairs glycemic control in type 2 diabetes in South China

An increase in branched-chain amino acid (BCAA) levels can result in insulin resistance at different stages of type 2 diabetes (T2D), however, the causes of this increase are unclear. We performed metagenomics and metabolomics profiling in patients with prediabetes (PDM), newly diagnosed diabetes (NDDM), and post-medication type 2 diabetes (P2DM) to investigate whether altered gut microbes and metabolites could explain the specific clinical characteristics of different disease stages of T2D. Here we identify acetolactate synthase (ALS) a BCAA biosynthesis enzyme in Staphylococcus aureus as a cause of T2D insulin resistance. Compared with healthy peoples, patients with PDM, NDDM, and P2DM groups, especially in P2DM group, have increased faecal numbers of S. aureus. We also demonstrated that insulin administration may be a risk factor for S. aureus infection in T2D. The presence of ALS-positive S. aureus correlated with the levels of BCAAs and was associated with an increased fasting blood glucose (FBG) and insulin resistance. Humanized microbiota transplantation experiment indicated that ALS contributes to disordered insulin resistance mediated by S. aureus. We also found that S. aureus phage can reduced the FBG levels and insulin resistance in db/db mice. The ALS-positive S. aureus are associated with insulin resistance in T2D, opening a new therapeutic avenue for the prevention or treatment of diabetes.

Glycation in Alzheimer's Disease and Type 2 Diabetes: The Prospect of Dual Drug Approaches for Therapeutic Interventions

As global life expectancy increases, the prevalence of neurodegenerative diseases like Alzheimer's disease (AD) continues to rise. Since therapeutic options are minimal, a deeper understanding of the pathophysiology is essential for improved diagnosis and treatments. AD is marked by the aggregation of Aβ proteins, tau hyperphosphorylation, and progressive neuronal loss, though its precise origins remain poorly understood. Meanwhile, type 2 diabetes mellitus (T2DM) is characterized by chronic hyperglycemia, leading to the formation of advanced glycation end products (AGEs), which are implicated in tissue damage and neurotoxicity. These AGEs can be resistant to proteolysis and, therefore, accumulate, exacerbating AD pathology and accelerating neurodegeneration. Insulin resistance, a hallmark of T2DM, further complicates AD pathogenesis by promoting tau hyperphosphorylation and Aβ plaque accumulation. Additionally, gut microbiome dysbiosis in T2DM fosters AGE accumulation and neuroinflammation, underscoring the intricate relationship between metabolic disorders, gut health, and neurodegenerative processes. This complex interplay presents both a challenge and a potential avenue for therapeutic intervention. Emerging evidence suggests that antidiabetic medications may offer cognitive benefits in AD, as well as in other neurodegenerative conditions, pointing to a shared pathophysiology. Thus, we posit that targeting AGEs, insulin signaling, and gut microbiota dynamics presents promising opportunities for innovative treatment approaches in AD and T2DM.

Restoration of intestinal secondary bile acid synthesis: A potential approach to improve pancreatic β cell function in type 1 diabetes

This study investigates the roles of gut microbiome and secondary bile acid dysfunctions in type 1 diabetes (T1D) and explores targeted interventions to address them. It finds that T1D is associated with reduced gut microbial diversity and imbalance favoring harmful bacteria over beneficial ones. Additionally, patients with T1D exhibited impaired secondary bile acid metabolism. Interventions aimed at modulating the gut microbiome and metabolites are safe and improve glycemic control, reduce daily insulin dose, and reduce inflammation. These interventions reshape the gut microbiome toward a healthier state and enhance secondary bile acid production. Responders to the interventions show increased levels of beneficial bacteria and secondary bile acids, along with improved C-peptide responses. Overall, these findings suggest that targeted modulation of the gut microbiome and secondary bile acid metabolism could be a promising therapeutic approach for T1D management. The trial is registered at Chinese Clinical Trial Registry (ChiCTR-ONN-17011279).

In vitro fermentation characteristics of polysaccharide from Scrophularia ningpoensis and its effects on type 2 diabetes mellitus gut microbiota

Background

Increasing evidence has shown a close relation between the pathogenesis of type 2 diabetes mellitus (T2DM), which is a global health problem with multifactorial etiopathogenesis, and gut microbiota.

Methods

During in-vitro fermentation of Scrophularia ningpoensis (known as Xuanshen) polysaccharide (SNP) by T2DM gut microbiota, effects of SNP on the gas content, production of short-chain fatty acids (SCFAs), metabolite profile and microbiota composition were studied.

Results

Analysis of chemical compositions indicates that the total sugar content of SNP was found to be as high as 87.35 ± 0.13% (w/w). SNP treatment significantly improved the gas volume and composition in T2DM fecal matter. Moreover, intestinal flora degraded SNP to produce SCFAs, thus regulating SCFA production and composition. Metabolomic analysis implied that SNP shows potential to regulate the five gut metabolites (L-valine, L-leucine, L-isoleucine, L-alanine, and xylitol) in T2DM fecal matter. Furthermore, dysbiosis of gut microbiota induced by T2DM was reversed by SNP. The evidence includes decreasing Firmicutes/Bacteroidota ratio at phylum level promoting proliferation of the bacterial abundance of Dorea, Parabacteroides, Faecalibacterium, and Lachnospira and decreased bacterial abundance of Escherichia-Shigella. Based on these findings, the action mechanism of SNP against T2DM was clarified by reshaping microbiota and regulating intestinal metabolites, and a novel target was provided for interventions of T2DM.

Characterization of Fecal Microbial Communities in Patients With Type 2 Diabetes Mellitus Combined With Helicobacter pylori Infection

BACKGROUND

Helicobacter pylori (H. pylori) infection has the capacity to alter the gut microbiota composition. There is a significant correlation between H. pylori infection and type 2 diabetes mellitus (T2DM). Further research is necessary to explore whether gut microbiota plays a role in the relationship between H. pylori and T2DM.

METHOD

Fecal samples were obtained from 44 patients with T2DM, including 20 who tested positive for H. pylori and 24 who tested negative. Intestinal microbiota composition was analyzed via 16S rRNA V3-V4 amplicon sequencing. Differences in microbial distribution and significant microbial biomarkers were identified between H. pylori positive and negative groups. A Spearman correlation analysis assessed the relationship between intestinal microbiota and glycemic parameters. Additionally, PICRUSt2 was used to predict intestinal bacterial functions.

RESULTS

Results indicate that in H. pylori (+) T2DM patients, HbA1c levels were significantly higher (8.9% vs. 8.1%, p = 0.021), while both the C-peptide peak (3.70 vs. 5.98 ng/mL, p = 0.040) and fasting C-peptide levels (1.42 vs. 2.31 ng/mL, p = 0.008) were significantly lower compared to H. pylori (-) T2DM groups. A total of 11 colonic phyla and 100 genera were identified in all fecal samples. In groups positive for H. pylori, there was a significant enrichment of the phylum Proteobacteria, while the genera Lactobacillus, Butyricimonas, and Akkermansia were significantly reduced (all p < 0.05). Correlation analysis showed that the abundance of the genera Butyricimonas (p = 0.01) and Akkermansia (p = 0.048) were negatively correlated with fasting plasma glucose. KEGG pathway analysis indicated a significant enrichment of methylmalonyl-CoA mutase and succinyl-CoA in H. pylori-infected T2DM patients.

CONCLUSIONS

This study suggests that T2DM patients with H. pylori infection exhibit more impaired pancreatic islet function potentially due to H. pylori-induced alterations in the gut microbiota.

Gut Microbial Metabolite Imidazole Propionate Impairs Endothelial Cell Function and Promotes the Development of Atherosclerosis

BACKGROUND

The microbially produced amino acid-derived metabolite imidazole propionate (ImP) contributes to the pathogenesis of type 2 diabetes. However, the effects of ImP on endothelial cell (EC) physiology and its role in atherosclerotic coronary artery disease are unknown. Using both human and animal model studies, we investigated the potential contributory role of ImP in the development of atherosclerosis.

METHODS

Plasma levels of ImP were measured in patients undergoing elective cardiac angiography (n=831) by ultra-high performance liquid chromatography coupled to tandem mass spectrometry. Odds ratios and corresponding 95% confidence intervals for coronary artery disease were calculated based on the ImP quartiles using both univariable and multivariable logistic regression models. The effects of ImP on functional properties of ECs were assessed using HAECs (human aortic endothelial cells). In a mouse model of carotid artery injury, the impact of ImP on vascular regeneration was examined. Additionally, atheroprone Apoe-/- mice fed a high-fat diet were treated with and without ImP (800 µg), and aortic atherosclerotic lesion area was evaluated after 12 weeks. Next-generation sequencing, Western blot analysis, small interfering RNA-based gene knockdown, and tamoxifen-inducible Cre-loxP experiments were performed to investigate ImP-mediated molecular mechanisms.

RESULTS

Plasma ImP levels in subjects undergoing cardiac evaluation were associated with increased risk of prevalent coronary artery disease. We found that ImP dose dependently impaired migratory and angiogenic properties of human ECs and promoted an increased inflammatory response. Long-term exposure to ImP compromised the repair potential of the endothelium after an arterial insult. In atheroprone Apoe-/- (apolipoprotein E-/-) mice, ImP increased atherosclerotic lesion size. Mechanistically, ImP attenuated insulin receptor signaling by suppressing the PI3K (phosphoinositide 3-kinase)/AKT pathway leading to sustained activation of the FOXO1 (forkhead box protein O1) transcription factor. Genetic inactivation of endothelial FOXO1 signaling in ImP-treated mice enhanced the angiogenic activity and preserved the vascular repair capacity of ECs after carotid injury.

CONCLUSIONS

Our findings reveal a hitherto unknown role of the microbially produced histidine-derived metabolite ImP in endothelial dysfunction and atherosclerosis, suggesting that ImP metabolism is a potential therapeutic target in atherosclerotic cardiovascular disease.

Gut Microbiota and Metabolic Dysregulation in Elderly Diabetic Patients: Is There a Gender-Specific Effect

Background/Objectives: The aim of this study was to qualitatively and quantitatively assess the bacterial domain of the gut microbiome in elderly patients with type 2 diabetes (T2D), with a focus on sex differences, glycemic control, and lipid disorders. Methods: This study included 60 older adults with T2D (38 women and 22 men) treated with metformin or a combination of metformin and insulin. The gut microbiota was profiled using 16S rRNA gene sequencing. Statistical analyses, including correlation analysis and multiple regression, were performed to identify the associations between microbial taxa, sex, and metabolic parameters. Results: No statistically significant differences in alpha or beta diversity were observed between the sexes. Multiple regression analysis indicated a positive relationship between Tenericutes and HbA1c in male participants (β = 2.22931, CI [0.75, 3.70], R = 0.67; R2 = 0.36; unadjusted p = 0.0052; adjusted p = 0.0496). In female participants, G0' (β = -2.24107, CI [-3.19, -1.30], R = 0.78; R2 = 0.58; unadjusted p = 0.00003; adjusted p = 0.0005) and HbA1c (β = -1.86670, CI [-2.61, -1.12], R = 0.78; R2 = 0.58; unadjusted p = 0.00001; adjusted p = 0.0003) correlated negatively with Verrucomicrobia as well G0' (β = -1.90427, CI [-2.95, -0.85], R = 0.46; R2 = 0.17; unadjusted p = 0.0008; adjusted p = 0.007) and HbA1c (β = -1.69561, CI [-2.52, -0.87], R = 0.46; R2 = 0.17; unadjusted p = 0.0002; adjusted p = 0.002) correlated negatively with OD1 bacteria, known as Parcubacteria. Conclusions: In this elderly population with type 2 diabetes, biological sex did not significantly affect the gut microbiota diversity. However, several exploratory associations between microbial taxa and metabolic parameters differed between men and women, suggesting that sex may influence specific aspects of microbiota-metabolism interactions. These preliminary findings underscore the importance of considering both age- and sex-related factors when investigating the gut microbiome in the context of type 2 diabetes.

Implication of taxonomic abundance of gut microbiota in prediabetes: a systematic review

Background

Prediabetes is defined by blood glucose levels that are higher than normal but below the diagnostic threshold for diabetes. Environmental factors associated with diabetes may contribute to its development through alterations in the gut microbiota. Recent studies suggest that changes in the composition and function of the gut microbiota play a role in the pathogenesis of diabetes mellitus and other metabolic disorders.

Objective

This study aims to systematically examine taxonomic abundance and its implications in the gut microbiota of individuals with prediabetes, identify key dysbiotic patterns, and explore their potential role in inflammation, insulin resistance, and progression to type 2 diabetes.

Methods

We conducted a systematic literature review following PRISMA guidelines. The review included sources from PubMed, ClinicalKey, ScienceDirect, Springer, and Scopus. We retrieved original research articles published in English that focused on prediabetes and gut microbiota from 2015 to the date of our search. Out of 827 full-text articles screened, 6 were selected based on defined inclusion and exclusion criteria.

Results

Dysbiosis of the gut microbiota in prediabetes is characterized by a reduction in butyrate-producing bacteria such as Faecalibacterium prausnitzii and Roseburia, along with an increase in potentially harmful taxa such as Escherichia/Shigella and Prevotella species. This imbalance is associated with systemic inflammation and insulin resistance, evidenced by elevated levels of C-reactive protein (CRP), interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α), and lipopolysaccharide-binding protein (LBP). Increased intestinal permeability facilitates the translocation of bacterial components such as lipopolysaccharides (LPS), further linking gut microbiota changes to the development of insulin resistance and type 2 diabetes.

Conclusion

This review highlights the need for further research to explore the potential therapeutic role of gut microbiota in prediabetes.

Systematic Review Registration

Prospero; Identifier CRD42025637369.

Gut microbiome research: Revealing the pathological mechanisms and treatment strategies of type 2 diabetes

The high prevalence and disability rate of type 2 diabetes (T2D) caused a huge social burden to the world. Currently, new mechanisms and therapeutic approaches that may affect this disease are being sought. With in-depth research on the pathogenesis of T2D and growing advances in microbiome sequencing technology, the association between T2D and gut microbiota has been confirmed. The gut microbiota participates in the regulation of inflammation, intestinal permeability, short-chain fatty acid metabolism, branched-chain amino acid metabolism and bile acid metabolism, thereby affecting host glucose and lipid metabolism. Interventions focusing on the gut microbiota are gaining traction as a promising approach to T2D management. For example, dietary intervention, prebiotics and probiotics, faecal microbiota transplant and phage therapy. Meticulous experimental design and choice of analytical methods are crucial for obtaining accurate and meaningful results from microbiome studies. How to design gut microbiome research in T2D and choose different machine learning methods for data analysis are extremely critical to achieve personalized precision medicine.

Fermented beetroot modulates gut microbial carbohydrate metabolism in prediabetes and prevents high-fat diet induced hyperglycemia in a prediabetic model

The global increase in prevalence of (pre-)diabetes demands immediate intervention strategies. In our earlier work, we demonstrated in vitro antidiabetic potential of a fermented beetroot product (PN39). Here, we examined the impact of PN39 on glucose tolerance and gut microbiota in C57BL/6J male mice and on prediabetic (PD) subjects' stool microbiota. In mice, high-fat diet (HFD) consumption for 9 weeks resulted in hyperglycemia and impaired glucose tolerance (GT) while concomitant consumption of PN39 and HFD (PN39+HFD) prevented GT impairment. Meanwhile, feeding the mice with HFD for 5 weeks to induce PD and later administering them with PN39 for 4 weeks (PD + PN39) neither improved fasting blood glucose nor GT. Relative to control groups, the gut microbiota of both PD mice and humans were characterized by decreased Clostridia UCG-014 and Lactobacilli as well as significantly altered gut microbial carbohydrate metabolism. Feeding PN39 together with HFD preserved Clostridia UCG-014 and Lactobacilli, increased short chain fatty acid production relative to mice fed with HFD only. Treating gut microbiota of PD subjects with PN39 however increased Clostridia UCG-014 and Lactobacilli populations and increased short chain fatty acids concentrations in the stools. In both mice and humans, PN39 treatment rectified the altered microbial carbohydrate metabolism observed in their PD counterparts. This suggests that the gut microbial modulatory effects of PN39 coupled with its capacity to regulate gut microbial glucose metabolism, likely played a role in preventing PD in mice receiving PN39+HFD. Taken together, our results indicate that PN39 could act as a potent antidiabetic functional food for preventing diabetes and its associated dysbiosis.

Microbiome-metabolome dynamics associated with impaired glucose control and responses to lifestyle changes

Type 2 diabetes (T2D) is a complex disease shaped by genetic and environmental factors, including the gut microbiome. Recent research revealed pathophysiological heterogeneity and distinct subgroups in both T2D and prediabetes, prompting exploration of personalized risk factors. Using metabolomics in two Swedish cohorts (n = 1,167), we identified over 500 blood metabolites associated with impaired glucose control, with approximately one-third linked to an altered gut microbiome. Our findings identified metabolic disruptions in microbiome-metabolome dynamics as potential mediators of compromised glucose homeostasis, as illustrated by the potential interactions between Hominifimenecus microfluidus and Blautia wexlerae via hippurate. Short-term lifestyle changes, for example, diet and exercise, modulated microbiome-associated metabolites in a lifestyle-specific manner. This study suggests that the microbiome-metabolome axis is a modifiable target for T2D management, with optimal health benefits achievable through a combination of lifestyle modifications.

Polysaccharide from Momordica charantia L. Alleviates Type 2 Diabetes Mellitus in Mice by Activating the IRS1/PI3K/Akt and AMPK Signaling Pathways and Regulating the Gut Microbiota

Developing effective therapies for type 2 diabetes mellitus (T2DM) remains a critical global health priority. This study explored the novel antidiabetic potential of MCPS-3, a polysaccharide derived from Momordica charantia L., and its underlying mechanisms in a high-fat diet and streptozotocin-induced T2DM mouse model. Our results indicated that MCPS-3 treatment significantly reduced serum glucose levels, improved glucose tolerance, and enhanced insulin sensitivity, alongside increased glycogen storage and improved liver enzyme activities. It also alleviated diabetes-induced damage in the pancreas, liver, and kidneys and improved serum lipid profiles by lowering triglycerides and LDL-C while increasing HDL-C levels. Mechanistic studies revealed that MCPS-3 activated the IRS1/PI3K/AKT and AMPK pathways, essential for glucose and lipid regulation. Importantly, MCPS-3 treatment restored gut microbial balance by increasing microbial diversity and shifting the composition of harmful and beneficial bacteria. Metabolomic analysis further identified changes in 46 metabolites, implicating pathways related to steroid and lipid metabolism. These findings underscore the multifaceted nature of MCPS-3's antidiabetic effects, including its role as a modulator of gut microbiota and metabolic pathways, and support its potential as a therapeutic agent for improving metabolic health in T2DM.

The gut microbiota and diabetic nephropathy: an observational study review and bidirectional Mendelian randomization study

BACKGROUND

Earlier studies have implicated a crucial link between diabetic nephropathy (DN) and the gut microbiota (GM) by considering the gut-kidney axis; however, the specific cause-and-effect connections between these processes remain unclear.

METHODS

To compare changes in the GM between DN patients and control subjects, a review of observational studies was performed. The examination focused on the phylum, family, genus, and species/genus categories. To delve deeper into the cause-effect relationship, instrumental variables for 211 GM taxa (9 phyla, 16 classes, 20 orders, 35 families, and 131 genera), which were eligible for the mbQTL (microbial quantitative trait locus) mapping analysis, were collected from the Genome Wide Association Study (GWAS). A Mendelian randomization investigation was then conducted to gauge their impact on DN susceptibility using data from the European Bioinformatics Institute (EBI) and the FinnGen consortium. The European Bioinformatics Institute data included 1032 DN patients and 451,248 controls, while the FinnGen consortium data consisted of 3283 DN patients and 210,463 controls. Two-sample Mendelian randomization (TSMR) was utilized to determine the link between the GM and DN. The primary method for analysis was the inverse variance weighted (IVW) approach. Moreover, a reverse Mendelian randomization analysis was carried out, and the findings were validated through sensitivity assessments.

RESULTS

This review examined 11 observational studies that satisfied the inclusion and exclusion criteria. There was a significant difference in the abundance of 144 GM taxa between DN patients and controls. By employing the MR technique, 13 bacteria were pinpointed as having a causal link to DN (including 3 unknown GM taxa). Even after Bonferroni correction, the protective impact of the phylum Proteobacteria and genus Dialister (Sequeira et al. Nat Microbiol. 5:304-313, 2020; Liu et al. EBioMedicine. 90:104527, 2023) and the harmful impact of the genus Akkermansia, family Verrucomicrobiaceae, order Verrucomicrobia and class Verrucomicrobiae on DN remained significant. No noticeable heterogeneity or horizontal pleiotropy was detected in the instrumental variables (IVs). However, reverse MR investigations have failed to reveal any substantial causal relationship between DN and the GM.

CONCLUSION

Differences in the GM among DN patients and healthy controls are explored in observational studies. We verified the possible connection between certain genetically modified genera and DN, thereby emphasizing the connection between the "gut-kidney" axis and new insights into the GM's role in DN pathogenesis underlying DN. Investigations into this association are necessary, and novel biomarkers for the development of targeted preventive strategies against DN are needed.

The Role of Short-Chain Fatty Acids in Metabolic Dysfunction-Associated Steatotic Liver Disease and Other Metabolic Diseases

With its increasing prevalence, metabolic dysfunction-associated steatotic liver disease (MASLD) has emerged as a major global public health concern over the past few decades. Growing evidence has proposed the microbiota-derived metabolites short-chain fatty acids (SCFAs) as a potential factor in the pathophysiology of MASLD and related metabolic conditions, such as obesity and type 2 diabetes mellitus (T2DM). By influencing key pathways involved in energy homeostasis, insulin sensitivity, and inflammation, SCFAs play an important role in gut microbiota composition, intestinal barrier function, immune modulation, and direct metabolic signaling. Furthermore, recent animal and human studies on therapeutic strategies targeting SCFAs demonstrate their potential for treating these metabolic disorders.

Machine Learning and Artificial Intelligence in the Multi-Omics Approach to Gut Microbiota

The gut microbiome is involved in human health and disease, and its comprehensive understanding is necessary to exploit it as a diagnostic or therapeutic tool. Multi-omics approaches, including metagenomics, metatranscriptomics, metabolomics, and metaproteomics, enable depiction of the gut microbial ecosystem's complexity. However, these tools generate a large data stream in which integration is needed to produce clinically useful readouts, but, in turn, might be difficult to carry out with conventional statistical methods. Artificial intelligence and machine learning have been increasingly applied to multi-omics datasets in several conditions associated with microbiome disruption, from chronic disorders to cancer. Such tools have potential for clinical implementation, including discovery of microbial biomarkers for disease classification or prediction, prediction of response to specific treatments, and fine-tuning of microbiome-modulating therapies. The state of the art, potential, and limits, of artificial intelligence and machine learning in the multi-omics approach to gut microbiome are discussed.

Multi-omics approaches for biomarker discovery and precision diagnosis of prediabetes

Recent advancements in multi-omics technologies have provided unprecedented opportunities to identify biomarkers associated with prediabetes, offering novel insights into its diagnosis and management. This review synthesizes the latest findings on prediabetes from multiple omics domains, including genomics, epigenomics, transcriptomics, proteomics, metabolomics, microbiomics, and radiomics. We explore how these technologies elucidate the molecular and cellular mechanisms underlying prediabetes and analyze potential biomarkers with predictive value in disease progression. Integrating multi-omics data helps address the limitations of traditional diagnostic methods, enabling early detection, personalized interventions, and improved patient outcomes. However, challenges such as data integration, standardization, and clinical validation and translation remain to be resolved. Future research leveraging artificial intelligence and machine learning is expected to further enhance the predictive power of multi-omics technologies, contributing to the precision diagnosis and tailored management of prediabetes.

The research progress and future directions in the pathophysiological mechanisms of type 2 diabetes mellitus from the perspective of precision medicine

Type 2 diabetes mellitus (T2DM) is a complex metabolic disorder characterized by pathophysiological mechanisms such as insulin resistance and β-cell dysfunction. Recent advancements in T2DM research have unveiled intricate multi-level regulatory networks and contributing factors underlying this disease. The emergence of precision medicine has introduced new perspectives and methodologies for understanding T2DM pathophysiology. A recent study found that personalized treatment based on genetic, metabolic, and microbiome data can improve the management of T2DM by more than 30%. This perspective aims to summarize the progress in T2DM pathophysiological research from the past 5 years and to outline potential directions for future studies within the framework of precision medicine. T2DM develops through the interplay of factors such as gut microbiota, genetic and epigenetic modifications, metabolic processes, mitophagy, NK cell activity, and environmental influences. Future research should focus on understanding insulin resistance, β-cell dysfunction, interactions between gut microbiota and their metabolites, and the regulatory roles of miRNA and genes. By leveraging artificial intelligence and integrating data from genomics, epigenomics, metabolomics, and microbiomics, researchers can gain deeper insights into the pathophysiological mechanisms and heterogeneity of T2DM. Additionally, exploring the combined effects and interactions of these factors may pave the way for more effective prevention strategies and personalized treatments for T2DM.

Microbial network inference for longitudinal microbiome studies with LUPINE

BACKGROUND

The microbiome is a complex ecosystem of interdependent taxa that has traditionally been studied through cross-sectional studies. However, longitudinal microbiome studies are becoming increasingly popular. These studies enable researchers to infer taxa associations towards the understanding of coexistence, competition, and collaboration between microbes across time. Traditional metrics for association analysis, such as correlation, are limited due to the data characteristics of microbiome data (sparse, compositional, multivariate). Several network inference methods have been proposed, but have been largely unexplored in a longitudinal setting.

RESULTS

We introduce LUPINE (LongitUdinal modelling with Partial least squares regression for NEtwork inference), a novel approach that leverages on conditional independence and low-dimensional data representation. This method is specifically designed to handle scenarios with small sample sizes and small number of time points. LUPINE is the first method of its kind to infer microbial networks across time, while considering information from all past time points and is thus able to capture dynamic microbial interactions that evolve over time. We validate LUPINE and its variant, LUPINE_single (for single time point analysis) in simulated data and four case studies, where we highlight LUPINE's ability to identify relevant taxa in each study context, across different experimental designs (mouse and human studies, with or without interventions, and short or long time courses). To detect changes in the networks across time and groups or in response to external disturbances, we used different metrics to compare the inferred networks.

CONCLUSIONS

LUPINE is a simple yet innovative network inference methodology that is suitable for, but not limited to, analysing longitudinal microbiome data. The R code and data are publicly available for readers interested in applying these new methods to their studies. Video Abstract.

Metformin as a potential antidepressant: Mechanisms and therapeutic insights in depression

Depression is one of the most disabling psychiatric disorders, whose pathophysiology has not been fully understood. Increasing numbers of preclinical studies have highlighted that metformin, as the first-line hypoglycaemic agent, has a potential pleiotropic effect on depression. Moreover, there is emerging evidence that metformin shows antidepressant activity and improves depressive symptoms in rodent models of depression. However, the exact role and underlying mechanism of metformin in depression remain unclear and still need to be investigated. Recent studies suggest that metformin not only improves neuronal damage and structural plasticity in the hippocampus but also enhances the antidepressant effect of antidepressants. Therefore, in this review, we summarize the existing evidence for the use of metformin as a psychopharmaceutical and elaborate on the underlying mechanisms of metformin in mitigating the onset and progression of depression, as well as the associated biochemical signaling pathways and targets involved in the pathogenesis of depression. After reviewing several studies, we conclude that metformin helps reduce depressive symptoms by targeting multiple pathways, including the regulation of neurotransmitters, enhanced neurogenesis, anti-inflammatory effects, and changes in gut microbiota. We aim to gain a deeper understanding of the mechanism of action of metformin and provide new insights into its clinical value in the prevention and therapy of depression.

The impact of novel probiotics isolated from the human gut on the gut microbiota and health

The gut microbiota plays a pivotal role in influencing the metabolism and immune responses of the body. A balanced microbial composition promotes metabolic health through various mechanisms, including the production of beneficial metabolites, which help regulate inflammation and support immune functions. In contrast, imbalance in the gut microbiota, known as dysbiosis, can disrupt metabolic processes and increase the risk of developing diseases, such as obesity, type 2 diabetes, and inflammatory disorders. The composition of the gut microbiota is dynamic and can be influenced by environmental factors such as diet, medication, and the consumption of live bacteria. Since the early 1900s, bacteria isolated from food and have been used as probiotics. However, the human gut also offers an enormous reservoir of bacterial strains, and recent advances in microbiota research have led to the discovery of strains with probiotic potentials. These strains, derived from a broad spectrum of microbial taxa, differ in their ecological properties and how they interact with their hosts. For most probiotics bacterial structural components and metabolites, such as short-chain fatty acids, contribute to the maintenance of metabolic and immunological homeostasis by regulating inflammation and reinforcing gut barrier integrity. Metabolites produced by probiotic strains can also be used for bacterial cross-feeding to promote a balanced microbiota. Despite the challenges related to safety, stability, and strain-specific properties, several newly identified strains offer great potential for personalized probiotic interventions, allowing for targeted health strategies.

Effect of broccoli sprout extract and baseline gut microbiota on fasting blood glucose in prediabetes: a randomized, placebo-controlled trial

More effective treatments are needed for impaired fasting glucose or glucose intolerance, known as prediabetes. Sulforaphane is an isothiocyanate that reduces hepatic gluconeogenesis in individuals with type 2 diabetes and is well tolerated when provided as a broccoli sprout extract (BSE). Here we report a randomized, double-blind, placebo-controlled trial in which drug-naive individuals with prediabetes were treated with BSE (n = 35) or placebo (n = 39) once daily for 12 weeks. The primary outcome was a 0.3 mmol l-1 reduction in fasting blood glucose compared with placebo from baseline to week 12. Gastro-intestinal side effects but no severe adverse events were observed in response to treatment. BSE did not meet the prespecified primary outcome, and the overall effect in individuals with prediabetes was a 0.2 mmol l-1 reduction in fasting blood glucose (95% confidence interval -0.44 to -0.01; P = 0.04). Exploratory analyses to identify subgroups revealed that individuals with mild obesity, low insulin resistance and reduced insulin secretion had a pronounced response (0.4 mmol l-1 reduction) and were consequently referred to as responders. Gut microbiota analysis further revealed an association between baseline gut microbiota and pathophysiology and that responders had a different gut microbiota composition. Genomic analyses confirmed that responders had a higher abundance of a Bacteroides-encoded transcriptional regulator required for the conversion of the inactive precursor to bioactive sulforaphane. The abundance of this gene operon correlated with sulforaphane serum concentration. These findings suggest a combined influence of host pathophysiology and gut microbiota on metabolic treatment response, and exploratory analyses need to be confirmed in future trials. ClinicalTrials.gov registration: NCT03763240 .

Associations of Dietary Live Microbes Intake and Prevalence of Prediabetes in US Adults: A Cross-Sectional Analysis

Objective

A higher dietary intake of live microbes has been shown to be associated with a range of health benefits. We aimed to elucidate the associations between dietary intake of live microbes and the risk of prediabetes.

Methods

Adult participants from the 1999-2018 US National Health and Nutrition Examination Survey were included and categorized into the low, medium, and high live microbe intake groups based on the Sanders classification system. Associations between dietary consumption of live microbes and prevalence of prediabetes were explored using univariate and multivariate logistic regression, stratified analysis, and sensitivity analysis.

Results

Among the 28201 participants (mean age 45.83 years, 48.40% men, 32.78% with prediabetes) included, 9761 (31.80%), 12,076 (41.42%) and 6364 (26.78%) were classified into the low, medium, and high dietary live microbe intake groups, respectively. After adjusting for all potential covariates, the odds ratios and 95% confidence intervals for the medium and high dietary live microbe intake groups were 0.868 (0.803-0.937) and 0.891 (0.807-0.983), respectively (P for trend = 0.017), with the low dietary live microbes intake group as the reference. This association is robust and not affected by participant's age, sex, race, poverty-income ratio, education level, hypertension status and estimated glomerular filtration rate.

Conclusion

A higher consumption of dietary live microbes was found to be cross-sectionally linked to a lower prevalence of prediabetes in US adults.

The relationship between dietary index for gut microbiota and diabetes

This study aims to explore the relationship between the Dietary Index for Gut Microbiota (DI-GM) and diabetes. In recent years, there has been increasing attention to the role of the gut microbiome in regulating host metabolism. However, the relationship between DI-GM and the risk of diabetes has not been sufficiently studied. This study utilized relevant data from the National Health and Nutrition Examination Survey (NHANES) 2007-2018. Multiple logistic regression analysis was conducted to explore the relationship between DI-GM and the risk of diabetes. The dose-response relationship between DI-GM and the risk of diabetes was observed using restricted cubic splines (RCS). Threshold effect analysis was performed based on RCS results. Subgroup analyses were used to conduct a sensitivity analysis of the relationship between DI-GM and the risk of diabetes. The results from multiple logistic regression analysis indicated a significant negative correlation between DI-GM and the risk of diabetes (OR, 0.954, 95%CI, 0.918-0.991). RCS results also showed a significant nonlinear negative relationship between DI-GM and the risk of diabetes (P < 0.001, P for nonlinear = 0.010). The threshold effect analysis revealed that when DI-GM was below 6.191, there was a significant negative correlation between DI-GM and the risk of diabetes (OR, 0.921, 95% CI, 0.876-0.969). However, when DI-GM exceeded 6.191, the relationship between DI-GM and the risk of diabetes was no longer significant. Subgroup analysis revealed that the negative correlation between DI-GM and the risk of diabetes remained significant in Whites, participants with a poverty-income ratio > 3.5, body mass index > 24, current drinkers, never or current smokers, and those without chronic kidney disease (P < 0.05). This study demonstrates a nonlinear negative correlation between DI-GM and the risk of diabetes. Maintaining DI-GM above 6.191 may help prevent diabetes.

Metagenome-informed metaproteomics of the human gut microbiome, host, and dietary exposome uncovers signatures of health and inflammatory bowel disease

Host-microbiome-dietary interactions play crucial roles in regulating human health, yet their direct functional assessment remains challenging. We adopted metagenome-informed metaproteomics (MIM), in mice and humans, to non-invasively explore species-level microbiome-host interactions during commensal and pathogen colonization, nutritional modification, and antibiotic-induced perturbation. Simultaneously, fecal MIM accurately characterized the nutritional exposure landscape in multiple clinical and dietary contexts. Implementation of MIM in murine auto-inflammation and in human inflammatory bowel disease (IBD) characterized a "compositional dysbiosis" and a concomitant species-specific "functional dysbiosis" driven by suppressed commensal responses to inflammatory host signals. Microbiome transfers unraveled early-onset kinetics of these host-commensal cross-responsive patterns, while predictive analyses identified candidate fecal host-microbiome IBD biomarker protein pairs outperforming S100A8/S100A9 (calprotectin). Importantly, a simultaneous fecal nutritional MIM assessment enabled the determination of IBD-related consumption patterns, dietary treatment compliance, and small intestinal digestive aberrations. Collectively, a parallelized dietary-bacterial-host MIM assessment functionally uncovers trans-kingdom interactomes shaping gastrointestinal ecology while offering personalized diagnostic and therapeutic insights into microbiome-associated disease.

Correlations Between Gut Microbiota Composition, Medical Nutrition Therapy, and Insulin Resistance in Pregnancy-A Narrative Review

Many physiological changes accompany pregnancy, most of them involving metabolic perturbations. Alterations in microbiota composition occur both before and during pregnancy and have recently been correlated with an important role in the development of metabolic complications, such as insulin resistance and gestational diabetes mellitus (GDM). These changes may be influenced by physiological adaptations to pregnancy itself, as well as by dietary modifications during gestation. Medical nutritional therapy (MNT) applied to pregnant women at risk stands out as one of the most important factors in increasing the microbiota's diversity at both the species and genus levels. In this review, we discuss the physiological changes during pregnancy and their impact on the composition of the intestinal microbiota, which may contribute to GDM. We also discuss findings from previous studies regarding the effectiveness of MNT in reducing insulin resistance. In the future, additional studies should aim to identify specific gut microbial profiles that serve as early indicators of insulin resistance during gestation. Early diagnosis, achievable through stool analysis or metabolite profiling, may facilitate the timely implementation of dietary or pharmaceutical modifications, thereby mitigating the development of insulin resistance and its associated sequelae.

Distinct Gut Microbiota Profiles in Normal Weight Obesity and Their Association With Cardiometabolic Diseases: Results From Two Independent Cohort Studies

BACKGROUND

Normal weight obesity (NWO) is characterized by excess body fat in individuals with normal body mass index (BMI). This study aimed to investigate gut microbiota alterations in NWO and their potential associations with cardiometabolic diseases (CMD) risk in two independent cohorts.

METHODS

Our NWO-CMD mortality analysis included 168 099 adults with normal BMI from two large open-access databases, while our NWO-gut microbiota study involved 5467 adults with normal BMI from two independent cohorts: the WELL-China cohort and the Lanxi cohort. NWO was defined as having a normal BMI (18.5-23.9 kg/m2) but an excess per cent body fat (PBF, ≥ 25% in men and ≥ 35% in women). Normal weight lean was defined as having a normal BMI and normal PBF. The 16S rRNA gene sequencing method was used to analyse gut microbiota data.

RESULTS

The study comprised 3620 (64.0% female, median age 58 years) and 1847 (64.3% female, median age 56 years) participants from the WELL-China and Lanxi cohorts. In our meta-analysis, NWO is associated with 26% (95% CI: 1.07-1.41) higher risk of CMD mortality. Gut microbial analyses indicated that the NWO group exhibited reduced levels of observed species (p = 0.009 and p = 0.013) and Chao 1 index (p = 0.002 and p = 0.002) and altered gut microbial compositions (p = 0.009 and p < 0.001) compared with the NWL group. Seven genera were consistently observed to be associated with NWO in both two cohorts (all Q < 0.25). Among them, five (Fusobacterium, Ruminococcus gnavus group, Ruminococcus torques group, Coprococcus and Christensenellaceae_R7_group) have been previously linked to obesity, while the other two (Phascolarctobacterium and Clostridia_UCG-014) were minimally reported. We also found statistically significant differences in the microbial composition between the NWO group and the obesity group (p = 0.001 and p = 0.001). Furthermore, the NWO-related gut microbiome was associated with an elevated risk of hypertension, dyslipidaemia and metabolic syndrome, the corresponding HR (95% CIs) were 1.11 (1.01-1.22), 1.19 (1.10-1.29) and 1.17 (1.05-1.30) in the WELL-China cohort and 1.14 (1.02-1.27), 1.15 (1.02-1.29) and 1.16 (1.02-1.32) in the Lanxi cohort.

CONCLUSIONS

These two large cohorts provided reliable evidence that gut microbiota alterations in NWO resemble those found in obesity, yet also display unique aspects. This distinct microbiota profile may contribute to heightened cardiometabolic risks in adults with normal BMI.

From human to superhuman: the impact of the microbiome on physiology

The complex microbial community residing in the human gut has long been understood to regulate gastrointestinal physiology and to participate in digestive diseases, but its extraintestinal actions and influences are increasingly recognized. This article discusses bidirectional interactions between the gut microbiome and athletic performance, metabolism, longevity and the ability of the gut-brain axis to influence cognitive function and mental health.

Coronary artery calcifications are not associated with epicardial adipose tissue volume and attenuation on computed tomography in 1,945 individuals with various degrees of glucose disorders

Background

The quantification of coronary artery calcifications (CAC) is a mainstay in radiological assessment of coronary atherosclerosis and cardiovascular risk, but reflect advanced, possibly late-stage changes in the arteries. Increased volume and changes in attenuation of the epicardial adipose tissue (EAT) on computed tomography (CT) have been linked to adverse cardiovascular events, and these changes in the EAT might reflect earlier stages of the processes leading to clinically manifest atherosclerosis. The relationship between EAT and CAC is subject to a knowledge gap, especially in individuals with no previously known coronary artery disease.

Methods

Fully automated EAT analysis with an artificial intelligence-based model was performed in a population sample enriched for pre-diabetics, comprising a total of 1,945 individuals aged 50-64 years, where non-contrast CT images, anthropometric and laboratory data was available on established cardiovascular risk factors. Uni- and multivariable linear regression, gradient-boosting and correlation analyses were performed to determine the explanatory value of EAT volume and attenuation data with regards to CAC data.

Results

Neither EAT volume nor EAT attenuation was associated with the presence or severity of CAC, when adjusting for established cardiovascular risk factors, and had only weak explanatory value in gradient-boosting and correlation analyses. Age was the strongest predictor of CAC in both sexes.

Conclusion

No independent association was found between CAC and total EAT volume or attenuation. Importantly, these findings do not rule out early stage or local effects on coronary atherosclerosis from the EAT immediately surrounding the coronary arteries.

Antibacterial activity and impact on keratinocyte cell growth of Cutibacterium acnes bacteriophages in a Cutibacterium acnes IA1- colonized keratinocyte model

Acne is an inflammatory disease in which microbial disbalance is represented by an augmented population of phylotype IA1 of Cutibacterium acnes. Various treatments for acne can cause side effects, and it has been reported that C. acnes is resistant to prescribed antibiotics. Phage therapy has been proposed as an alternative treatment for acne, given its species-specificity to kill bacteria, its relative innocuity, and its potential to manage antibiotic-resistant pathogens. Moreover, bacteriophages (phages) may modulate the microbiota and immune responses. Some studies have shown the potential use of phages in the treatment of acne. Nevertheless, the capacity to specifically reduce phylotype IA1 and the effect of phage treatment on skin cells are poorly understood. We assessed the capacity of phages to clear C. acnes IA1 and their effects on cell cytotoxicity and growth in HEKa cells- C. acnes IA1 co-culture. Phylotypes IA1 and IB had similar effects on HEKa cells, causing cytotoxicity and diminishing cell growth. Nevertheless, IA1 caused a higher impact on cell doubling time by increasing it 1.8 times more than cell growth control group. Even though there are no phages IA1-specific, we found phages that have a diminished effect on other phylotypes not related to acne. Phage treatment in general reduced IA1-caused cytotoxicity, with differences in efficacy among phages. In addition, phage purification was necessary to restore metabolic activity and growth of HEKa. Overall, phage evaluation as a therapeutic alternative should include phage-bacteria interactions and their impact on skin cells because of the differences that each phage can exhibit.

Gut bacterium Intestinimonas butyriciproducens improves host metabolic health: evidence from cohort and animal intervention studies

BACKGROUND

The human gut microbiome strongly influences host metabolism by fermenting dietary components into metabolites that signal to the host. Our previous work has shown that Intestinimonas butyriciproducens is a prevalent commensal bacterium with the unique ability to convert dietary fructoselysine to butyrate, a well-known signaling molecule with proven health benefits. Dietary fructoselysine is an abundant Amadori product formed in foods during thermal treatment and is part of foods rich in dietary advanced glycation end products which have been associated with cardiometabolic disease. It is therefore of interest to investigate the causal role of this bacterium and fructoselysine metabolism in metabolic disorders.

RESULTS

We assessed associations of I. butyriciproducens with metabolic risk biomarkers at both strain and functional levels using a human cohort characterized by fecal metagenomic analysis. We observed that the level of the bacterial strain as well as fructoselysine fermentation genes were negatively associated with BMI, triglycerides, HbA1c, and fasting insulin levels. We also investigated the fructoselysine degradation capacity within the Intestinimonas genus using a culture-dependent approach and found that I. butyriciproducens is a key player in the butyrogenic fructoselysine metabolism in the gut. To investigate the function of I. butyriciproducens in host metabolism, we used the diet-induced obesity mouse model to mimic the human metabolic syndrome. Oral supplementation with I. butyriciproducens counteracted body weight gain, hyperglycemia, and adiposity. In addition, within the inguinal white adipose tissue, bacterial administration reduced inflammation and promoted pathways involved in browning and insulin signaling. The observed effects may be partly attributable to the formation of the short-chain fatty acids butyrate from dietary fructoselysine, as butyrate plasma and cecal levels were significantly increased by the bacterial strain, thereby contributing to the systemic effects of the bacterial treatment.

CONCLUSIONS

I. butyriciproducens ameliorates host metabolism in the context of obesity and may therefore be a good candidate for new microbiota-therapeutic approaches to prevent or treat metabolic diseases. Video Abstract.

The causal relationship of cigarette smoking to metabolic disease risk and the possible mediating role of gut microbiota

BACKGROUND

Cigarette smoking is a leading cause of preventable death worldwide, with its associated diseases and conditions. Emerging evidence suggests that cigarette smoking contributes to a range of pathological metabolic injuries, including diabetes and nonalcoholic fatty liver disease (NAFLD). The impact of gut microbiota on metabolic health and diseases has been observed, but the causality remains uncertain.

OBJECTIVE

To confirm the causal relationship between cigarette smoking and metabolic diseases, and to investigate the possible mediating effect of gut microbiota on these connections.

METHODS

The relationships among cigarette smoking, metabolic diseases, and the gut microbiome were analyzed by Univariate Mendelian randomization (UVMR). Furthermore, to mitigate the impact of confounding factors, adjusted models were conducted via the multivariate Mendelian randomization (MVMR) method, aiming to improve the accuracy of prediction. Ultimately, the study evaluated the effect of the intermediary factor, gut microbiome, on the relationship between cigarette smoke and metabolic diseases.

RESULTS

The phenomenon that a causal relationship between cigarette smoke (249752 individuals) and gut microbiota (7738 individuals), diabetes (406831 individuals), NAFLD (377998 individuals), hypercholesterolaemia (463010 individuals), and obesity (463010 individuals) was observed using UVMR. In the MVMR model, the genetic connection between cigarette smoking, gut microbiota, and type 2 diabetes remained significant. Of note, paraprevotella_clara served an important mediating role in the type 2 diabetes associated with cigarette smoke.

CONCLUSION

This work offered genetic evidence linking cigarette smoke to metabolic diseases, suggesting that the gut microbiota, particularly paraprevotella_clara, might be a crucial mediator in the development of type 2 diabetes caused by cigarette smoke. Our future studies should consider conducting other ethnic groups MR analyses, particularly with larger sample sizes. Still, more in vivo and in vitro work should be carried out to validate the precise effect and molecular mechanisms of the gut microbiome.

Novel insights into the role of gut microbiota and its metabolites in diabetic chronic wounds

Wounds in patients with diabetes present significant physical and economic challenges due to impaired healing and prolonged inflammation, exacerbated by complex interactions between microbes. Especially, the development and healing of diabetic foot ulcers (DFUs) remain an urgent clinical problem. The human gut harbors a vast microbial ecosystem comprising intestinal flora and their metabolic products. Recent advancements in research have illuminated the concept of the "gut-skin axis," revealing intricate relationships between gut microbiota, microbiota-derived metabolites, and various skin diseases, including DFUs. This review aims to unravel the formation and healing process of DFUs in the context of the gut-skin axis. We reviewed the current research progress worldwide regarding to the gut-skin axis, compared and discussed significant changes in the microbiota colonizing the skin and gut in patients with DFUs. The roles of microbiota-derived metabolites such as lipopolysaccharides, short-chain fatty acids, and trimethylamine-N-oxide in the development of DFUs are highlighted. We also reviewed treatment strategies currently employed in clinical practice and identified potential therapeutic targets such as probiotics for treating DFUs. The need for more comprehensive experimental designs to elucidate the intricate relationship between gut microbiota and its metabolites in the context of DFUs are therefore highlighted.

Understanding Patterns of the Gut Microbiome May Contribute to the Early Detection and Prevention of Type 2 Diabetes Mellitus: A Systematic Review

The rising burden of type 2 diabetes mellitus (T2DM) is a growing global public health problem, particularly prominent in developing countries. The early detection of T2DM and prediabetes is vital for reversing the outcome of disease, allowing early intervention. In the past decade, various microbiome-metabolome studies have attempted to address the question of whether there are any common microbial patterns that indicate either prediabetic or diabetic gut microbial signatures. Because current studies have a high methodological heterogeneity and risk of bias, we have selected studies that adhered to similar design and methodology. We performed a systematic review to assess if there were any common changes in microbiome belonging to diabetic, prediabetic and healthy individuals. The cross-sectional studies presented here collectively covered a population of 65,754 people, with 1800 in the 2TD group, 2770 in the prediabetic group and 61,184 in the control group. The overall microbial diversity scores were lower in the T2D and prediabetes cohorts in 86% of the analyzed studies. Re-programming of the microbiome is potentially one of the safest and long-lasting ways to eliminate diabetes in its early stages. The differences in the abundance of certain microbial species could serve as an early warning for a dysbiotic gut environment and could be easily modified before the onset of disease by changes in lifestyle, taking probiotics, introducing diet modifications or stimulating the vagal nerve. This review shows how metagenomic studies have and will continue to identify novel therapeutic targets (probiotics, prebiotics or targets for elimination from flora). This work clearly shows that gut microbiome intervention studies, if performed according to standard operating protocols using a predefined analytic framework (e.g., STORMS), could be combined with other similar studies, allowing broader conclusions from collating all global cohort studies efforts and eliminating the effect-size statistical insufficiency of a single study.

Diabetes and gut microbiome

Diabetes mellitus represents a significant global health problem. The number of people suffering from this metabolic disease is constantly rising and although the incidence is heterogeneous depending on region, country, economic situation, lifestyle, diet and level of medical care, it is increasing worldwide, especially among youths and children, mainly due to lifestyle and environmental changes. The pathogenesis of the two most common subtypes of diabetes mellitus, type 1 (T1DM) and type 2 (T2DM), is substantially different, so each form is characterized by a different causation, etiology, pathophysiology, presentation, and treatment. Research in recent decades increasingly indicates the potential role of the gut microbiome in the initiation, development, and progression of this disease. Intestinal microbes and their fermentation products have an important impact on host metabolism, immune system, nutrient digestion and absorption, gut barrier integrity and protection against pathogens. This review summarizes the current evidence on the changes in gut microbial populations in both types of diabetes mellitus. Attention is focused on changes in the abundance of specific bacterial groups at different taxonomic levels in humans, and microbiome shift is also assessed in relation to geographic location, age, diet and antidiabetic drug. The causal relationship between gut bacteria and diabetes is still unclear, and future studies applying new methodological approaches to a broader range of microorganisms inhabiting the digestive tract are urgently needed. This would not only provide a better understanding of the role of the gut microbiome in this metabolic disease, but also the use of beneficial bacterial species in the form of probiotics for the treatment of diabetes.

Impact of Ketogenic and Mediterranean Diets on Gut Microbiota Profile and Clinical Outcomes in Drug-Naïve Patients with Diabesity: A 12-Month Pilot Study

Background/Objectives: Managing type 2 diabetes mellitus (T2DM) and obesity requires a multidimensional, patient-centered approach including nutritional interventions (NIs) and physical activity. Changes in the gut microbiota (GM) have been linked to obesity and the metabolic alterations typical of T2DM and obesity, and they are strongly influenced by diet. However, few studies have evaluated the effects on the GM of a very-low-calorie ketogenic diet (VLCKD) in patients with T2DM, especially in the mid-term and long-term. This longitudinal study is aimed at evaluating the mid-term and long-term impact of the VLCKD and Mediterranean diet (MD) on the GM and on the anthropometric, metabolic, and lifestyle parameters of 11 patients with T2DM and obesity (diabesity). This study extends previously published results evaluating the short-term (three months) impact of these NIs on the same patients. Methods: At baseline, patients were randomly assigned to either a VLCKD (KETO group) or a Mediterranean diet (MEDI group). After two months, the KETO group gradually shifted to a Mediterranean diet (VLCKD-MD), according to current VLCKD guidelines. From the fourth month until the end of the study both groups followed a similar MD. Previous published results showed that VLCKD had a more beneficial impact than MD on several variables for 3 months of NI. In this study, the analyses were extended until six (T6) and twelve months (T12) of NI by comparing data prospectively and against baseline (T0). The GM analysis was performed through next-generation sequencing. Results: Improvements in anthropometric and metabolic parameters were more pronounced in the KETO group at T6, particularly for body mass index (-5.8 vs. -1.7 kg/m2; p = 0.006) and waist circumference (-15.9 vs. -5.2 cm; p = 0.011). At T6, a significant improvement in HbA1c (6.7% vs. 5.5% p = 0.02) and triglyceride (158 vs. 95 mg/dL p = 0.04) values compared to T0 was observed only in the KETO group, which maintained the results achieved at T3. The VLCKD-MD had a more beneficial impact than the MD on the GM phenotype. A substantial positive modulatory effect was observed especially up to the sixth month of the NI in KETO due to the progressive increase in bacterial markers of human health. After the sixth month, most markers of human health decreased, though they were still increased compared with baseline. Among them, the Verrucomicrobiota phylum was identified as the main biomarker in the KETO group, together with its members Verrucomicrobiae, Akkermansiaceae, Verrucomicrobiales, and Akkermansia at T6 compared with baseline. Conclusions: Both dietary approaches ameliorated health status, but VLCKD, in support of the MD, has shown greater improvements on anthropometric and metabolic parameters, as well as on GM profile, especially up to T6 of NI.

Effects of Cordyceps cicadae Polysaccharide on Gut Microbiota, the Intestinal Mucosal Barrier, and Inflammation in Diabetic Mice

Background: Polysaccharides produced by the edible fungus Cordyceps cicadae can regulate blood sugar levels and may represent a suitable candidate for the treatment of diabetes and its complications. However, there is limited information available about the mechanism of how C. cicadae polysaccharide (CCP) might improve diabetic conditions. Methods: This study investigated its effects on the intestinal microbiota, intestinal mucosal barrier, and inflammation in mice with type 2 diabetes mellitus (T2DM) induced by streptozotocin, and its potential mechanisms. Results: Compared with the DC (diabetes model control group), CCPH oral treatment significantly increased the number of beneficial bifidobacteria, bifidobacteria, and lactobacilli (p < 0.01), restored the diversity of intestinal microorganisms in diabetic mice, and the proportions of Firmicutes and Bacteroidetes (34.36%/54.65%) were significantly lower than those of the DC (52.15%/32.09%). Moreover, CCPH significantly reduced the content of endotoxin (lipopolysaccharide, LPS) and D-lactic acid(D-LA) (p < 0.05), the activities of antioxidant enzymes and total antioxidant capacity were significantly increased (p < 0.01), and the content of proinflammatory cytokines TNF-α, IL-6, and IL-1β were reduced by 42.05%, 51.28%, and 52.79%, respectively, compared with the DC. The TLR4/NF-κB signaling pathway, as a therapeutic target for diabetic intestinal diseases, plays a role in regulating the inflammatory response and protecting the intestinal barrier function. Molecular mechanism studies showed that oral treatment with CCPH down-regulated the expression of NF-κB, TLR-4, and TNF-α genes by 18.66%, 21.58%, and 34.87%, respectively, while up-regulating the expression of ZO-1 and occludin genes by 32.70% and 25.11%, respectively. CCPH regulates the expression of short-chain fatty acid levels, increases microbial diversity, and ameliorates mouse colon lesions by inhibiting the TLR4/NF-κB signaling pathway. Conclusions: In conclusion, it is demonstrated that in this murine model, the treatment of diabetes with C. cicadae polysaccharide can effectively regulate intestinal microbiota imbalance, protect intestinal mucosal barrier function, and reduce inflammation in vivo, suggesting this natural product can provide a suitable strategy for the treatment of T2D-induced gut dysbiosis and intestinal health.

Targeting gut microbiota by starch molecular size and chain-length distribution to produce various short-chain fatty acids

The detailed relationships among starch fine molecular structures, gut microbiota, and short-chain fatty acids (SCFAs) are not fully understood. We hypothesized that specific starch molecular size and chain-length distribution are favored by gut bacteria for the secretion of SCFAs. To investigate this, different types of starches with diverse molecular size and chain-length distributions (e.g., amylose content ranging from about 1 % to 38 %) were subjected to in vitro fermentation with human fecal inocula. Tapioca and waxy maize starches were notably more effective at producing acetate and propionate compared to lentil, wheat, and pea starches (p < 0.05). Correlation analysis revealed, for the first time, that the number of amylose chains with a degree of polymerization between 500 and 5000 was positively correlated with the abundance of Bacteroides_coprocola_DSM_17136 and Bacteroides_plebeius, possibly relating to the higher production of acetate and propionate. These results indicate that starches with certain fine molecular structures could be used to target gut bacteria to produce various types of SCFAs, thereby amplifying beneficial effects on human health.

The Relationship Between Gut Microbiota, Muscle Mass and Physical Function in Older Individuals: A Systematic Review

BACKGROUND

Recent evidence suggests that sarcopenia and subsequent changes in muscle mass and functional outcomes are linked to disruption to the gastrointestinal microbiota composition and/or function via the microbiota-gut-muscle axis. Despite growing interest, few studies have systemically analysed (1) the relationship between the gut microbiota, muscle mass and physical performance and (2) the effects of gut-modulating dietary interventions on these outcomes within older individuals with or without sarcopenia.

METHODS

Four electronic databases (PubMed, MEDLINE, Embase and Scopus) were searched for articles published from the year 2004 until July 2023. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) were followed. Revised Cochrane Risk of Bias (RoB 2.0) and Joanna Briggs Institute (JBI) critical appraisal checklist were utilised to evaluate the risk of bias within intervention and observational studies, respectively.

RESULTS

A total of 20 studies (14 observational and 6 interventional) involving 4071 older participants (mean age 69.9 years, 51.6% female) were included. There was significant heterogeneity regarding interventions and outcome measures used in these studies. Correlations between microbiota diversity and composition and sarcopenia-related functional outcomes were observed. Interventional studies targeting the gut microbiota resulted in improved muscle strength, body composition or physical function in some, but not all, studies.

CONCLUSIONS

Despite limitations in the studies reviewed, the findings provide further evidence that the development of sarcopenia is likely influenced by an altered gut microbial environment and that interventions targeting the microbiome could hold therapeutic potential for the treatment or management of sarcopenia.

Effects of probiotic supplementation on the anthropometric nutritional status of patients with type 2 Diabetes mellitus: A systematic review and meta-analysis protocol

BACKGROUND

Diabetes mellitus (DM) is characterized by hyperglycemia due to insufficient insulin production or utilization. Previous studies have shown a relationship between the gut microbiota and DM, driving interest in probiotic supplementation to modulate the microbiota and glucose metabolism in patients with DM, although the exact mechanisms remain unclear. Probiotics can influence metabolic factors and improve the composition of the microbiota, possibly helping to reduce weight in patients with DM.

OBJECTIVE

The objective of this review is to compile and analyze the most relevant evidence on the effects of probiotic supplementation on the nutritional anthropometric status of patients with type 2 Diabetes mellitus (T2DM).

METHODS

Methodological guidelines will be followed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement and the study has been registered in the International Prospective Register of Systematic Reviews under reference number CRD42023480243. Studies will be selected through an active search of the PubMed, Science Direct, and SCOPUS databases using the following search descriptors: gut microbiota, body weight, and metabolic diseases, according to medical subject headings. The assessment of the methodological quality of the studies will be carried out using the Cochrane Collaboration instrument. The risk of bias will be analyzed using the Revised Cochrane tool for risk of bias in randomized controlled trials (RoB 2). A meta-analysis will be performed if heterogeneity is acceptable and justifiable; otherwise, the results will be presented in a qualitative narrative synthesis.

EXPECTED RESULTS

The results of probiotic supplementation are expected to demonstrate improvements in anthropometric parameters such as body weight, BMI and abdominal and waist circumference in patients with T2DM, thus providing valuable evidence for clinical application.

Soy protein β-conglycinin ameliorates pressure overload-induced heart failure by increasing short-chain fatty acid (SCFA)-producing gut microbiota and intestinal SCFAs

BACKGROUND AND AIMS

Soybeans and their ingredients have antioxidant and anti-inflammatory effects on cardiovascular diseases. β-Conglycinin (β-CG), a major constituent of soy proteins, is protective against obesity, hypertension, and chronic kidney disease, but its effects on heart failure remain to be elucidated. We tested the effects of β-CG on left ventricular (LV) remodeling in pressure overload-induced heart failure.

METHODS

A transverse aortic constriction (TAC)-induced pressure overload was applied to the heart in 7-week-old C57BL6 male mice that were treated with β-CG, GlcNAc, or sodium propionate. Gut microbiota was analyzed by 16S rRNA sequencing. Fecal short-chain fatty acids (SCFAs) were quantified by GC-MS. The effects of oral antibiotics were examined in β-CG-fed mice.

RESULTS

β-CG ameliorated impaired cardiac contractions, cardiac hypertrophy, and myocardial fibrosis in TAC-operated mice. As β-CG is a highly glycosylated protein, we examined the effects of GlcNAc. GlcNAc had similar but less efficient effects on LV remodeling compared to β-CG. β-CG increased three major SCFA-producing intestinal bacteria, as well as fecal concentrations of SCFAs, in sham- and TAC-operated mice. Oral administration of antibiotics nullified the effects of β-CG in TAC-operated mice by markedly reducing SCFA-producing intestinal bacteria and fecal SCFAs. In contrast, oral administration of sodium propionate, one of SCFAs, ameliorated LV remodeling in TAC-operated mice to a similar extent as β-CG.

CONCLUSIONS

β-CG was protective against TAC-induced LV remodeling, which was likely to be mediated by increased SCFA-producing gut microbiota and increased intestinal SCFAs. Modified β-CG and/or derivatives arising from β-CG are expected to be developed as prophylactic and/or therapeutic agents to ameliorate devastating symptoms in heart failure.

Causal relationships between gut microbiome and aplastic anemia: a Mendelian randomization analysis

BACKGROUND

Previous observational studies have hinted at a potential correlation between aplastic anemia (AA) and the gut microbiome. However, the precise nature of this bidirectional causal relationship remains uncertain.

METHODS

We conducted a bidirectional two-sample Mendelian randomization (MR) study to investigate the potential causal link between the gut microbiome and AA. Statistical analysis of the gut microbiome was based on data from an extensive meta-analysis (genome-wide association study) conducted by the MiBioGen Alliance, involving 18,340 samples. Summary statistical data for AA were obtained from the Integrative Epidemiology Unit database. Single -nucleotide polymorphisms (SNPs) were estimated and summarized using inverse variance weighted (IVW), MR Egger, and weighted median methods in the bidirectional MR analysis. Cochran's Q test, MR Egger intercept test, and sensitivity analysis were employed to assess SNP heterogeneity, horizontal pleiotropy, and stability.

RESULTS

The IVW analysis revealed a significant correlation between AA and 10 bacterial taxa. However, there is currently insufficient evidence to support a causal relationship between AA and the composition of gut microbiome.

CONCLUSION

This study suggests a causal connection between the prevalence of specific gut microbiome and AA. Further investigation into the interaction between particular bacterial communities and AA could enhance efforts in prevention, monitoring, and treatment of the condition.

Exploring the relationship between gut microbiota and breast diseases using Mendelian randomization analysis

Background

Growing evidence suggests a relationship between gut microbiota composition and breast diseases, although the precise nature of this association remains uncertain. To investigate the causal relationship between gut microbiota and breast diseases, we utilized two-way Mendelian randomization (MR) analysis.

Methods

Four common diseases were included as outcomes: breast cancer, breast cysts, inflammatory disorders of the breast, and infections of the breast associated with childbirth, along with their subtypes. Genetic data on gut microbiota were extracted from genome-wide association studies (GWAS). The primary approach used to investigate the association between these genetic factors and gut microbiota was the inverse-variance-weighted (IVW) method with random-effects types. Sensitivity analyses, such as Cochran's Q test, the MR-Egger intercept test, and leave-one-out analysis, were conducted to ensure the stability and reliability of the MR findings.

Results

We discovered plausible causal links between 20 microbial categories and the breast diseases, with a significance level of p < 0.05. Notably, Family.Rikenellaceae (p: 0.0013) maintained a significant inverse relationship with overall breast cancer (BC), after the Bonferroni correction. In the reverse MR analysis, interactions were observed between Genus.Adlercreutzia and estrogen receptor-positive cancer. In addition, Genus.Sellimonas, Family.Rikenellaceae, and Genus.Paraprevotella were associated with ER+ and overall breast cancer, whereas Genus.Dorea was linked to both estrogen receptor-negative and overall breast cancer. Family.Prevotellaceae was the only category correlated with inflammatory breast disorders. Moreover, Genus Eubacteriumruminantiumgroup, Genus.Lactococcus, and Family.Alcaligenaceae were associated with breast cysts, while Genus.Anaerofilum, Genus.Butyricimonas, Order.Coriobacteriales, Order.Pasteurellales, and Order.Verrucomicrobiales showed significant associations with infections of the breast associated with childbirth. No evidence of heterogeneity or horizontal pleiotropy was found.

Conclusion

Our Mendelian randomization analysis confirmed a causal relationship between gut microbiota and breast diseases. Early stool tests may be a viable method for screening diseases to identify people at higher risk of breast diseases.

Gut Microbe-Generated Metabolite Trimethylamine-N-Oxide and Ischemic Stroke

Trimethylamine-N-oxide (TMAO) is a gut microbiota-derived metabolite, the production of which in vivo is mainly regulated by dietary choices, gut microbiota, and the hepatic enzyme flavin monooxygenase (FMO), while its elimination occurs via the kidneys. The TMAO level is positively correlated with the risk of developing cardiovascular diseases. Recent studies have found that TMAO plays an important role in the development of ischemic stroke. In this review, we describe the relationship between TMAO and ischemic stroke risk factors (hypertension, diabetes, atrial fibrillation, atherosclerosis, thrombosis, etc.), disease risk, severity, prognostic outcomes, and recurrence and discuss the possible mechanisms by which they interact. Importantly, TMAO induces atherosclerosis and thrombosis through lipid metabolism, foam cell formation, endothelial dysfunction (via inflammation, oxidative stress, and pyroptosis), enhanced platelet hyper-reactivity, and the upregulation and activation of vascular endothelial tissue factors. Although the pathogenic mechanisms underlying TMAO's aggravation of disease severity and its effects on post-stroke neurological recovery and recurrence risk remain unclear, they may involve inflammation, astrocyte function, and pro-inflammatory monocytes. In addition, this paper provides a summary and evaluation of relevant preclinical and clinical studies on interventions regarding the gut-microbiota-dependent TMAO level to provide evidence for the prevention and treatment of ischemic stroke through the gut microbe-TMAO pathway.

Roseburia intestinalis: A possible target for vascular calcification

With the advancement of metagenomics and metabolomics techniques, the crucial role of the gut microbiome in intestinal, cardiovascular, and metabolic disorders has been extensively explored. Vascular calcification (VC) is common in atherosclerosis, hypertension, diabetes mellitus, and chronic kidney disease. Moreover, it is a significant cause of cardiovascular diseases and mortality. Roseburia intestinalis, as a promising candidate for the next generation of probiotics, plays a substantial role in inhibiting the systemic inflammatory response and holds great potential in the treatment of intestinal diseases, cardiovascular diseases, and metabolic disorders. Its primary metabolite, butyrate, acts on specific receptors (GPR43, GPR41, GPR109a). It enters cells via transporters (MCT1, SMCT1), affecting gene expression through HDACs, PPARγ and Nrf2, promoting energy metabolism and changing the concentration of other metabolites (including AGEs, LPS, BHB) in the circulation to affect the body's life activities. In this paper, we focus on the possible mechanism of the primary metabolite butyrate of Roseburia intestinalis in inhibiting VC, which may become a potential therapeutic target for the treatment of VC and the ways to enhance its effect.

Reinventing gut health: leveraging dietary bioactive compounds for the prevention and treatment of diseases

The human gut harbors a complex and diverse microbiota essential for maintaining health. Diet is the most significant modifiable factor influencing gut microbiota composition and function, particularly through bioactive compounds like polyphenols, dietary fibers, and carotenoids found in vegetables, fruits, seafood, coffee, and green tea. These compounds regulate the gut microbiota by promoting beneficial bacteria and suppressing harmful ones, leading to the production of key microbiota-derived metabolites such as short-chain fatty acids, bile acid derivatives, and tryptophan metabolites. These metabolites are crucial for gut homeostasis, influencing gut barrier function, immune responses, energy metabolism, anti-inflammatory processes, lipid digestion, and modulation of gut inflammation. This review outlines the regulatory impact of typical bioactive compounds on the gut microbiota and explores the connection between specific microbiota-derived metabolites and overall health. We discuss how dietary interventions can affect disease development and progression through mechanisms involving these metabolites. We examine the roles of bioactive compounds and their metabolites in the prevention and treatment of diseases including inflammatory bowel disease, colorectal cancer, cardiovascular diseases, obesity, and type 2 diabetes mellitus. This study provides new insights into disease prevention and underscores the potential of dietary modulation of the gut microbiota as a strategy for improving health.

Characteristics of Gut Microbiome in the Murine Model of Pancreatic Cancer with Damp-Heat Syndrome

PURPOSE

Murine models of pancreatic cancer with damp-heat syndrome were established based on two methods to explore the differences in the composition of intestinal flora and to seek characteristic genera with potential for model evaluation.

METHODS

In our study, thirty-four C57BL/6J male mice were randomly divided into a control group (Con), a model group (Mod), a classic damp-heat syndrome group (CDHS), and a climate-chamber group (CC). CDHS and CC groups were fed with a high-fat diet and glucose water, while the CDHS group was given 2.4 g/kg alcohol by gavage for 10 days, and the CC group was placed in a climatic chamber with a set temperature of (32 ± 1) °C and humidity of (92 ± 2)% for 10 days. The Mod group, CDHS group, and CC group underwent tumor-building experiments on day 11. Tumorigenicity was then assessed twice a week. After 4 weeks, feces, colon tissue, and tumor tissue were taken from the mice and were tested, and the mice were euthanized afterwards.

RESULTS

Mice in the CDHS and CC groups showed symptoms similar to the clinical damp-heat syndrome observed in traditional Chinese medicine (TCM), and exhibited a worse general condition and more rapid tumor growth trend than those in the Mod group. The pathological examination indicated that inflammation was prevalent in the CDHS and CC groups. Both groups had a disrupted intestinal barrier and an overgrowth of pathogenic bacteria such as c_Gammaproteobacteria, o_Enterobacteriales, and g_Bacteroides. Their microbiota composition showed greater diversity.

CONCLUSIONS

Intestinal flora may have a promising future in the discovery of indicators for evaluating a model of damp-heat syndrome in pancreatic cancer.