Type 2 Diabetes and the Microbiome

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.

Understanding the role of family functioning, dietary adherence, and culture on glycemic control among adults with type 2 diabetes: A mediation and moderation analysis

BACKGROUND

Families and cultural contexts can impact dietary adherence and glycemic control of type 2 diabetes (T2D). Yet little is known about these relationships in Africa, where poor dietary adherence and glycemic control are prevalent. To address this gap, this study investigated whether dietary adherence mediates family functioning and glycemic control among T2D adults in Benin, West Africa. We also explored whether cultural identity affected the association between family functioning and dietary adherence.

METHODS

A cross-sectional study of 512 T2D patients from six health centers was conducted to assess: 1) family functioning with the 12-item McMaster Family Assessment Device-General Functioning Subscale (FAD-GF); 2) dietary adherence via the Perceived Dietary Adherence Questionnaire (PDAQ); and 3) cultural identity with the 12-item Multigroup Ethnic Identity Measure (MEIM). The three-month glycemic control was determined with Glycated Hemoglobin - HbA1c. Mediation and moderation analyses were conducted using Stata's structural equation model (SEM).

RESULTS

Healthy family functioning, good dietary adherence and good glycemic control rates were 56.8%, 33%, and 30.5% respectively. Path analysis showed that healthy family functioning was significantly associated with lower HbA1c levels (-0.34, 95% CI: [-0.72, -0.03]), and there was a significant indirect effect via greater dietary adherence (-0.12, 95% CI: [-0.22, -0.01]). However, cultural identity did not significantly impact the relationship between family functioning and dietary adherence.

CONCLUSIONS

Our study revealed that family functioning, adherence to dietary recommendations, and glycemic control are interconnected in adults with T2D. Interventions should target modifiable factors like dietary adherence and address relevant risk and resilience sources to improve glycemic control in urban African families.

The differences of metabolic profiles, socioeconomic status and diabetic retinopathy in U.S. working-age and elderly adults with diabetes: results from NHANES 1999-2018

AIMS

Controlled metabolic factors and socioeconomic status (SES) was crucial for prevention of diabetic retinopathy (DR). The study aims to assess the metabolic factors control and SES among working-age adults (18-64 years) with diabetes compared to older adults (65 years and older).

METHODS

Totals of 6738 participants with self-reported diagnosed diabetes from National Health and Nutrition Examination Survey were included, of whom 3482 were working-age and 3256 were elderly. The prevalence of DR, metabolic factors control, and the impact of SES and diabetic duration on DR was estimated. Subgroup analysis among working-age adults was employed across different diabetic duration and SES level.

RESULTS

The prevalence of DR was 20.8% among working-age adults and 20.6% in elderly adults. Further, working-age adults possessed suboptimal control on glycemia (median HbA1c: 7.0% vs. 6.8%, p < 0.001) and lipids (Low-density lipoprotein < 100 mg/dL: 46.4% vs. 63.5%, p < 0.001), but better blood pressure control (< 130/80 mmHg: 53.5% vs. 37.5%, p < 0.001) compared to the elderly, judging based on age-specific control targets. Prolonged diabetic duration didn't improve glycemic and composite factors control. SES like education and income impacted metabolic factors control and adults with higher SES were more likely to control well. Diabetic duration was a significant risk factor (OR = 4.006, 95%CI= (2.752,5.832), p < 0.001) while higher income (OR = 0.590, 95%CI= (0.421,0.826), p = 0.002) and educational level (OR = 0.637, 95%CI= (0.457,0.889), p = 0.008) were protective against DR.

CONCLUSIONS

Working-age adults with diabetes demonstrate suboptimal metabolic profile control, especially glycemia and lipids. Additional efforts are needed to improve metabolic factor control and reduce DR risk, particularly for those with longer diabetes duration, less education, and lower incomes.

Microbial and proteomic signatures of type 2 diabetes in an Arab population

BACKGROUND

The rising prevalence of Type 2 diabetes mellitus (T2D) in the Qatari population presents a significant public health challenge, highlighting the need for innovative approaches to early detection and management. While most efforts are centered on using blood samples for biomarker discovery, the use of saliva remains underexplored.

METHODS

Using noninvasive saliva samples from 2974 Qatari subjects, we analyzed the microbial communities from diabetic, pre-diabetic, and non-diabetic participants based on their HbA1C levels. The salivary microbiota was assessed in all subjects by sequencing the V1-V3 regions of 16S rRNA gene. For the proteomics profiling, we randomly selected 50 gender and age-matched non-diabetic and diabetic subjects and compared their proteome with SOMAscan. Microbiota and proteome profiles were then integrated to reveal candidate biomarkers for T2D.

RESULTS

Our results indicate that the salivary microbiota of pre-diabetic and diabetic individuals differs significantly from that of non-diabetic subjects. Specifically, a significant increase in the abundance of Campylobacter, Dorea, and Bacteroidales was observed in the diabetic subjects compared to their non-diabetic controls. Metabolic pathway prediction analysis for these bacteria revealed a significant overrepresentation of genes associated with fatty acid and lipid biosynthesis, as well as aromatic amino acid metabolism in the diabetic group. Additionally, we observed distinct differences in salivary proteomic profiles between diabetic and non-diabetic subjects. Notably, levels of Haptoglobin, Plexin-C1, and MCL-1 were elevated, while Osteopontin (SPP1), Histone1H3A (HIST3H2A), and Histone H1.2 were reduced in diabetic individuals. Furthermore, integrated correlation analysis of salivary proteome and microbiota data demonstrated a strong positive correlation between HIST1H3A and HIST3H2A with Porphyromonas sp., all of which were decreased in the diabetic group.

CONCLUSION

This is the first study to assess the salivary microbiota in T2D patients from a large cohort of the Qatari population. We found significant differences in the salivary microbiota of pre-diabetic and diabetic individuals compared to non-diabetic controls. Our study is also the first to assess the salivary proteome using SOMAScan in diabetic and non-diabetic subjects. Integration of the microbiota and proteome profiles revealed a unique signature for T2D that can be used as potential T2D biomarkers.

A Meta-Analysis of the Human Gut Mycobiome Using Internal Transcribed Spacer Data

The intestinal mycobiome is closely related to human health. There have been several reports investigating the association between the gut fungi and disease, but there is still a lack of overall assessment of the human gut mycobiome. Here, we performed a meta-analysis based on 2372 ITS (Internal Transcribed Spacer) data collected publicly online. We found that the mycobiome diversity of human gut fungi varies significantly across diseases by using EasyAmplicon, and these fungi are mainly composed of three genera, Saccharomyces, Candida, and Aspergillus. In addition, we performed the construction of disease prediction models based on ITS data by using the random forest model and verified the generalization ability of the models. We hope that our results will provide strong support for subsequent studies of the intestinal mycobiome.

The importance of gut microbiome in the perinatal period

This narrative review describes the settlement of the neonatal microbiome during the perinatal period and its importance on human health in the long term. Delivery methods, maternal diet, antibiotic exposure, feeding practices, and early infant contact significantly shape microbial colonization, influencing the infant's immune system, metabolism, and neurodevelopment. By summarizing two decades of research, this review highlights the microbiome's role in disease predisposition and explores interventions like maternal vaginal seeding and probiotic and prebiotic supplementation that may influence microbiome development.

CONCLUSION

The perinatal period is a pivotal phase for the formation and growth of the neonatal microbiome, profoundly impacting long-term health outcomes.

WHAT IS KNOWN

• The perinatal period is a critical phase for the development of the neonatal microbiome, with factors such as mode of delivery, maternal diet, antibiotic exposure, and feeding practices influencing its composition and diversity, which has significant implications for long-term health. • The neonatal microbiome plays a vital role in shaping the immune system, metabolism, and neurodevelopment of infants.

WHAT IS NEW

• Recent studies have highlighted the potential of targeted interventions, such as probiotic and prebiotic supplementation, and innovative practices like maternal vaginal seeding, to optimize microbiome development during the perinatal period. • Emerging evidence suggests that specific bacterial genera and species within the neonatal microbiome are associated with reduced risks of developing chronic conditions, indicating new avenues for promoting long-term health starting from early life.

Advancements in precision medicine: multi-omics approach for tailored metformin treatment in type 2 diabetes

Metformin has become the frontline treatment in addressing the significant global health challenge of type 2 diabetes due to its proven effectiveness in lowering blood glucose levels. However, the reality is that many patients struggle to achieve their glycemic targets with the medication and the cause behind this variability has not been investigated thoroughly. While genetic factors account for only about a third of this response variability, the potential influence of metabolomics and the gut microbiome on drug efficacy opens new avenues for investigation. This review explores the different molecular signatures to uncover how the complex interplay between genetics, metabolic profiles, and gut microbiota can shape individual responses to metformin. By highlighting the insights from recent studies and identifying knowledge gaps regarding metformin-microbiota interplay, we aim to highlight the path toward more personalized and effective diabetes management strategies and moving beyond the one-size-fits-all approach.

Gut microbiome's causal role in head and neck cancer: findings from mendelian randomization

Introduction

The gut microbiome (GM) has been implicated in cancer pathogenesis and treatment, including head and neck cancers (HNC). However, the specific microbial compositions influencing HNC and the underlying mechanisms remain largely unknown.

Methods

This study utilized published genome-wide association studies (GWAS) summary data-based two-sample Mendelian randomization (MR) to uncover the GM compositions that exert significant causal effects on HNC. Functional annotation and enrichment analysis were conducted to better understand the significant genetic variables and their connection with HNC. The HNC dataset included 2,281 cases and 314,193 controls. The GM GWAS data of 211 gut taxa (35 families, 20 orders, 16 classes, 9 phyla, and 131 genera) were obtained from the MibioGen consortium, involving 18,340 participants.

Results

MR analysis revealed four GM compositions exerting causal effects on HNC. Specifically, family Peptococcaceae.id.2024 was significantly associated with a 35% reduced risk of HNC (OR=0.65; 95%CI=0.48-0.90; P=0.0080). In contrast, genus DefluviitaleaceaeUCG-011.id.11287 (OR=1.54; 95%CI=1.13-2.09; P=0.0060), genus Gordonibacter.id.821 (OR=1.23; 95%CI=1.05-1.45; P=0.012), and genus Methanobrevibacter.id.123 (OR=1.28; 95%CI=1.01-1.62; P=0.040) showed a significant association with an increased risk of HNC. These GMs interact with genes and genetic variants involved in signaling pathways, such as GTPase regulation, influencing tumor progression and disease prognosis.

Conclusions

Our study demonstrates, for the first time, the causal influence of specific gut microbiome compositions on HNC, offering significant insights for advancing clinical research and personalized treatments. The identified GMs may serve as potential biomarkers or therapeutic targets, paving the way for innovative approaches in HNC diagnosis, prevention, and therapy.

Morus alba: natural and valuable effects in weight loss management

Overweight and obesity are conditions associated with serious comorbidities, such as diabetes and cardiovascular disease. Prevalence of excessive fat accumulation is increasing worldwide, and thus the need for efficient and sustainable weight loss regimes has become a major issue in clinical practice. Despite the important advances in the development of anti-obesity medications (AOM), their side effects, cost, and accessibility, are limiting factors for their routine use. Conversely, the studies of medicinal plants for weight management holds strong promise as a growing area of research. This review consolidates the representative evidence about the beneficial impacts of Morus alba on weight management and associated metabolic parameters, encompassing: inhibition of digestive enzymes, and thus contribution to the energy deficit required for weight loss, improvements in glucose and lipid metabolism, and attenuation of adiposity. Findings from in vitro, in vivo, and clinical investigations reviewed in the paper, demonstrate that white mulberry extracts have the potency to supplement efficiently and safely a healthy weight management approach.

Gut microbiome: A revolution in type II diabetes mellitus

Type II diabetes mellitus (T2DM) has experienced a dramatic increase globally across countries of various income levels over the past three decades. The persistent prevalence of T2DM is attributed to a complex interplay of genetic and environmental factors. While numerous pharmaceutical therapies have been developed, there remains an urgent need for innovative treatment approaches that offer effectiveness without significant adverse effects. In this context, the exploration of the gut microbiome presents a promising avenue. Research has increasingly shown that the gut microbiome of individuals with T2DM exhibits distinct differences compared to healthy individuals, suggesting its potential role in the disease's pathogenesis and progression. This emerging field offers diverse applications, particularly in modifying the gut environment through the administration of prebiotics, probiotics, and fecal microbiome transfer. These inter-ventions aim to restore a healthy microbiome balance, which could potentially alleviate or even reverse the metabolic dysfunctions associated with T2DM. Although current results from clinical trials have not yet shown dramatic effects on diabetes management, the groundwork has been laid for deeper investigation. Ongoing and future clinical trials are critical to advancing our understanding of the microbiome's impact on diabetes. By further elucidating the mechanisms through which microbiome alterations influence insulin resistance and glucose metabolism, researchers can develop more targeted interventions. The potential to harness the gut microbiome in developing new therapeutic strategies offers a compelling prospect to transform the treatment landscape of T2DM, potentially reducing the disease's burden significantly with approaches that are less reliant on traditional pharmaceuticals and more focused on holistic, systemic health improvements.

Unveiling contrasts in microbiota response: A1c control improves dysbiosis in low-A1c T2DM, but fails in high-A1c cases-a key to metabolic memory?

INTRODUCTION

Type 2 diabetes mellitus (T2DM) is associated with dysbiosis in the gut microbiota (MB). Individually, each medication appears to partially correct this. However, there are no studies on the response of the MB to changes in A1c. Therefore, we investigated the MB's response to intensive glycemic control.

RESEARCH DESIGN AND METHODS

We studied two groups of patients with uncontrolled T2DM, one group with an A1c <9% (18 patients-G1) and another group with an A1c >9% (13 patients-G2), aiming for at least a 1% reduction in A1c. We collected A1c and fecal samples at baseline, 6, and 12 months. G1 achieved an average A1c reduction of 1.1%, while G2 a reduction of 3.13%.

RESULTS

G1's microbiota saw a decrease in Erysipelotrichaceae_UCG_003 and in Mollicutes order (both linked to metabolic syndrome and associated comorbidities). G2, despite having a more significant reduction in A1c, experienced an increase in the proinflammatory bacteria Megasphaera and Acidaminococcus, and only one beneficial genus, Phascolarctobacterium, increased, producer of butyrate.

CONCLUSION

Despite a notable A1c outcome, G2 could not restore its MB. This seeming resistance to change, leading to a persistent inflammation component found in G2, might be part of the "metabolic memory" in T2DM.

Mechanisms of microbiota modulation: Implications for health, disease, and therapeutic interventions

Microbiota modulation, the intentional change in the structure and function of the microbial community, is an emerging trajectory that holds the promise to mitigate an infinite number of health issues. The present review illustrates the underlying principles of microbiota modulation and the various applications of this fundamental process to human health, healthcare management, and pharmacologic interventions. Different strategies, directing on dietary interventions, fecal microbiota transplantation, treatment with antibiotics, bacteriophages, microbiome engineering, and modulation of the immune system, are described in detail. This therapeutic implication is reflected in clinical applications to gastrointestinal disorders and immune-mediated diseases for microbiota-modulating agents. In addition to this, the review outlines the challenges of translating researched outcomes into clinical practice to consider safety and provides insights into future research directions of this rapidly developing area.

Consuming artificial sweeteners may alter the structure and function of duodenal microbial communities

Studies using stool samples suggest that non-sugar sweetener (NSS) consumption affects gut microbiome composition. However, stool does not represent the entire gut. We analyzed the duodenal luminal microbiome in subjects consuming non-aspartame non-sugar sweeteners (NANS, N = 35), aspartame only (ASP, N = 9), and controls (CON, N = 55) and the stool microbiome in a subset (N = 40). Duodenal alpha diversity was decreased in NANS vs. CON. Duodenal relative abundance (RA) of Escherichia, Klebsiella, and Salmonella (all phylum Proteobacteria) was lower in both NANS and ASP vs. CON, whereas stool RA of Escherichia, Klebsiella, and Salmonella was increased in both NANS and ASP vs. CON. Predicted duodenal microbial metabolic pathways altered in NANS vs. CON included polysaccharides biosynthesis and D-galactose degradation, whereas cylindrospermopsin biosynthesis was significantly enriched in ASP vs. CON. These findings suggest that consuming non-sugar sweeteners may significantly alter microbiome composition and function in the metabolically active small bowel, with different alterations seen in stool.