OBJECTIVE: To investigate whether the association between insulin resistance and cardiovascular disease (CVD) differs by glucose tolerance status. RESEARCH DESIGN AND METHODS: We analyzed a nationwide sample of 111,576 adults without CVD at baseline, using data from the China Cardiometabolic Disease and Cancer Cohort Study. Insulin resistance was estimated by sex-specific HOMA of insulin resistance (HOMA-IR) quartiles for participants with normal glucose tolerance, prediabetes, or diabetes, separately, and by 1 SD of HOMA-IR for the overall study participants. We used Cox proportional hazards models to examine the association between insulin resistance and incident CVD according to glucose tolerance status and evaluate the CVD risk associated with the combined categories of insulin resistance and obesity in prediabetes and diabetes, as compared with normal glucose tolerance. Models were adjusted for age, sex, education attainment, alcohol drinking, smoking, physical activity, and diet quality. RESULTS: In participants with normal glucose tolerance, prediabetes, and diabetes defined by three glucose parameters, multivariable-adjusted hazard ratios (95% CIs) for incident CVD associated with the highest versus the lowest quartile of HOMA-IR were 1.03 (0.82–1.30), 1.23 (1.07–1.42), and 1.61 (1.30–2.00), respectively; the corresponding values for CVD per 1-SD increase in HOMA-IR were 1.04 (0.92–1.18), 1.12 (1.06–1.18), and 1.15 (1.09–1.21), respectively (P for interaction = 0.011). Compared with participants with normal glucose tolerance, in participants with prediabetes, the combination of the highest HOMA-IR quartile and obesity showed 17% (95% CI 2–34%) higher risk of CVD, while the combination of the lowest two HOMA-IR quartiles and nonobesity showed 15–17% lower risk of CVD. In participants with diabetes, the upper two HOMA-IR quartiles exhibited 44–77% higher risk of CVD, regardless of obesity status. Consistent findings were observed for glucose tolerance status defined by different combinations of glycemic parameters. CONCLUSIONS: Glucose intolerance status exacerbated the association between insulin resistance and CVD risk. Compared with adults with normal glucose tolerance, adults with prediabetes who were both insulin resistant and obese exhibited higher risks of CVD, while in adults with diabetes, the CVD risk related to insulin resistance remained, regardless of obesity.

Diabetic kidney disease (DKD) is the leading cause of end-stage renal diseases. DKD does not have efficacious treatment. The cGAS-STING pathway is activated in podocytes at the early stage of kidney dysfunction, which is associated with the activation of STING downstream effectors TBK1 and NF-κB but not IRF3. Lipotoxicity induces mitochondrial damage and mtDNA leakage to the cytosol through Bcl-2 associated X protein (BAX) in podocytes. BAX-mediated mtDNA cytosolic leakage can activate the cGAS-STING pathway in the absence of lipotoxicity and is sufficient to cause podocyte injury. Depletion of cytosolic mtDNA, genetic STING knockdown, or pharmacological inhibition of STING or TBK1 alleviates podocyte injury and improves renal functions in cultured podocytes or mouse models of diabetes and obesity. These results suggest that the mtDNA-cGAS-STING pathway promotes podocyte injury and is a potential therapeutic target for DKD or other obesity-related kidney diseases.

Background. More and more studies focus on the relationship between the gastrointestinal microbiome and type 2 diabetes, but few of them have actually explored the relationship between enterotypes and type 2 diabetes. Materials and Methods. We enrolled 134 patients with type 2 diabetes and 37 nondiabetic controls. The anthropometric and clinical indices of each subject were measured. Fecal samples of each subject were also collected and were processed for 16S rDNA sequencing. Multiple logistic regression analysis was used to determine the associations of enterotypes with type 2 diabetes. Multiple linear regression analysis was used to explore the relationship between lipopolysaccharide levels and insulin sensitivity after adjusting for age, BMI, TG, HDL-C, DAO, and TNF-α. The correlation analysis between factors and microbiota was identified using Spearman correlation analysis. The correlation analysis between factors was identified using partial correlation analysis. Results. Gut microbiota in type 2 diabetes group exhibited lower bacterial diversity compared with nondiabetic controls. The fecal communities from all subjects clustered into two enterotypes distinguished by the levels of Bacteroides and Prevotella. Logistic regression analysis showed that the Bacteroides enterotype was an independent risk factor for type 2 diabetes by decreasing insulin sensitivity. The levels of lipopolysaccharide and tumor necrosis factor-alpha were higher in the Bacteroides enterotype compared to the Prevotella enterotype. Partial correlation analysis showed that lipopolysaccharide was closely associated with diamine oxidase, tumor necrosis factor-alpha, and Gutt insulin sensitivity index after adjusting for multiple covariates. Furthermore, the level of lipopolysaccharide was found to be an independent risk factor for insulin sensitivity. Conclusions. We identified two enterotypes, Bacteroides and Prevotella, among all subjects. Our results showed that the Bacteroides enterotype was an independent risk factor for type 2 diabetes, which was due to increased levels of lipopolysaccharide causing decreased insulin sensitivity.

OBJECTIVE Comprehensive assessment of serum bile acids (BAs) aberrations before diabetes onset remains inconclusive. We examined the association of serum BA profile and coregulation with the risk of developing type 2 diabetes mellitus (T2DM) among normoglycemic Chinese adults. RESEARCH DESIGN AND METHODS We tested 23 serum BA species in subjects with incident diabetes (n = 1,707) and control subjects (n = 1,707) matched by propensity score (including age, sex, BMI, and fasting glucose) from the China Cardiometabolic Disease and Cancer Cohort (4C) Study, which was composed of 54,807 normoglycemic Chinese adults with a median follow-up of 3.03 years. Multivariable-adjusted odds ratios (ORs) for associations of BAs with T2DM were estimated using conditional logistic regression. RESULTS In multivariable-adjusted logistic regression analysis, per SD increment of unconjugated primary and secondary BAs were inversely associated with incident diabetes, with an OR (95% CI) of 0.89 (0.83–0.96) for cholic acid, 0.90 (0.84–0.97) for chenodeoxycholic acid, and 0.90 (0.83–0.96) for deoxycholic acid (P < 0.05 and false discovery rate <0.05). On the other hand, conjugated primary BAs (glycocholic acid, taurocholic acid, glycochenodeoxycholic acid, taurochenodeoxycholic acid, and sulfated glycochenodeoxycholic acid) and secondary BA (tauroursodeoxycholic acid) were positively related with incident diabetes, with ORs ranging from 1.11 to 1.19 (95% CIs ranging between 1.05 and 1.28). In a fully adjusted model additionally adjusted for liver enzymes, HDL cholesterol, diet, 2-h postload glucose, HOMA-insulin resistance, and waist circumference, the risk estimates were similar. Differential correlation network analysis revealed that perturbations in intraclass (i.e., primary and secondary) and interclass (i.e., unconjugated and conjugated) BA coregulation preexisted before diabetes onset. CONCLUSIONS These findings reveal novel changes in BAs exist before incident T2DM and support a potential role of BA metabolism in the pathogenesis of diabetes.