Impact of baseline and trajectory of the atherogenic index of plasma on incident diabetic kidney disease and retinopathy in participants with type 2 diabetes: a longitudinal cohort study.

BACKGROUND: Some studies have assessed the predictive role of the atherogenic index of plasma (AIP) for macrovascular diseases. This prospective investigation aimed to elucidate whether AIP is associated with diabetic kidney disease (DKD) and diabetic retinopathy (DR) incidence. METHODS: The data were extracted from 4831 participants, of whom 2943 and 3360 participants with type 2 diabetes (T2D) were included in the DKD and DR follow-up analyses, respectively. Cox regression models were performed to test the relationships of AIP value at baseline with the risk of incident DKD and DR. Group-based trajectory modelling was utilized to discern AIP trajectories during the follow-up period. Subsequently, logistic regressions were applied to ascertain the influence of AIP trajectories on the incidence of DKD and DR. RESULTS: During the follow-up period, 709 (24.1%) and 193 (5.7%) participants developed DKD and DR, respectively. The median (interquartile range) follow-up time was 24.2 (26.3) months for DKD and 25.7 (27.0) months for DR. According to the multivariate Cox regression models, baseline AIP was positively and linearly related to the occurrence of DKD, with a hazard ratio of 1.75 (95% confidence interval [CI] 1.36-2.26). Three distinct trajectories of AIP were identified throughout the follow-up time: Low (31.4%), Median (50.2%), and High (18.3%). Compared to participants with the Low AIP trajectory, those with High and Median AIP trajectories presented 117% (95% CI: 1.62-2.91) and 84% (95% CI 1.46-2.32) greater odds of developing DKD, respectively. However, neither baseline levels nor trajectories of AIP were shown to be related to DR after adjusting for confounding factors. CONCLUSIONS: Baseline levels and trajectories of AIP were independently related to elevated DKD risk, indicating that AIP could be used as a predictor for identifying T2D participants at higher risk of DKD. No association between AIP and DR was detected.

Visit-to-visit HbA1c variability is associated with aortic stiffness progression in participants with type 2 diabetes.

BACKGROUND: Glycemic variability plays an important role in the development of cardiovascular disease (CVD). This study aims to determine whether long-term visit-to-visit glycemic variability is associated with aortic stiffness progression in participants with type 2 diabetes (T2D). METHODS: Prospective data were obtained from 2115 T2D participants in the National Metabolic Management Center (MMC) from June 2017 to December 2022. Two brachial-ankle pulse wave velocity (ba-PWV) measurements were performed to assess aortic stiffness over a mean follow-up period of 2.6 years. A multivariate latent class growth mixed model was applied to identify trajectories of blood glucose. Logistic regression models were used to determine the odds ratio (OR) for aortic stiffness associated with glycemic variability evaluated by the coefficient of variation (CV), variability independent of the mean (VIM), average real variability (ARV), and successive variation (SV) of blood glucose. RESULTS: Four distinct trajectories of glycated hemoglobin (HbA1c) or fasting blood glucose (FBG) were identified. In the U-shape class of HbA1c and FBG, the adjusted ORs were 2.17 and 1.21 for having increased/persistently high ba-PWV, respectively. Additionally, HbA1c variability (CV, VIM, SV) was significantly associated with aortic stiffness progression, with ORs ranging from 1.20 to 1.24. Cross-tabulation analysis indicated that the third tertile of the HbA1c mean and VIM conferred a 78% (95% confidence interval [CI] 1.23-2.58) higher odds of aortic stiffness progression. Sensitivity analysis demonstrated that the SD of HbA1c and the highest HbA1c variability score (HVS) were significantly associated with the adverse outcomes independent of the mean of HbA1c during the follow-up. CONCLUSIONS: Long-term visit-to-visit HbA1c variability was independently associated with aortic stiffness progression, suggesting that HbA1c variability was a strong predictor of subclinical atherosclerosis in T2D participants.

Stronger association of triglyceride glucose index than the HOMA-IR with arterial stiffness in patients with type 2 diabetes: a real-world single-centre study.

BACKGROUND: The triglyceride-glucose index (TyG index) has been proposed as a simple and reliable alternative insulin resistance (IR) marker, while the homeostasis model assessment for IR (HOMA-IR) is the most frequently used index. Few studies have evaluated the role of IR assessed by the TyG index and HOMA-IR on arterial stiffness in a type 2 diabetes (T2D) population with a high risk of increased arterial stiffness. We aimed to investigate the association of the TyG index and HOMA-IR with arterial stiffness in patients with T2D. METHODS: We recruited 3185 patients with T2D, who underwent brachial-ankle pulse wave velocity (baPWV), an indicator of arterial stiffness, but without previous cardiovascular disease. Increased arterial stiffness was defined as a baPWV value greater than the 75th percentile (18.15 m/s) in the present study. The TyG index was determined as ln(fasting triglycerides [mg/dL] × fasting glucose [mg/dL]/2), and the HOMA-IR was calculated as (fasting insulin [µIU/mL] × fasting glucose [mmol/L])/22.5. RESULTS: The mean age of the study participants was 54.6 ± 12.0 years, and 1954 (61.4%) were men. Seemingly unrelated regression estimation analysis demonstrated that the TyG index had stronger associations with baPWV than the HOMA-IR (all P < 0.001). In the multivariable logistic analyses, each one-unit increase in the TyG index was associated with a 1.40-fold (95% CI 1.16-1.70, P < 0.001) higher prevalence of increased arterial stiffness, but the prominent association of the HOMA-IR with the prevalence of increased arterial stiffness was not observed. Subgroup analyses showed that a more significant association between the TyG index and the prevalence of increased arterial stiffness was detected in older patients with a longer duration of diabetes and poor glycaemic control (all P < 0.05). CONCLUSIONS: Compared with the HOMA-IR, the TyG index is independently and more strongly associated with arterial stiffness in patients with T2D.

Betulinic acid improves nonalcoholic fatty liver disease through YY1/FAS signaling pathway.

The increasing prevalence of nonalcoholic fatty liver disease (NAFLD) worldwide indicates the urgent need to develop novel and effective treatment strategies. Betulinic acid (BA), a naturally occurring plant-derived pentacyclic triterpenoid, has an outstanding effect in improving metabolism. However, the pharmacological action and mechanism of BA in NAFLD remain unclear. Here, we show that BA-treated high-fat diet mice and methionine-choline deficient diet-fed mice are resistant to hepatic steatosis when compared with vehicle-treated mice. BA alleviates fatty acid synthesis, fibrosis, and inflammation and promotes fatty acid oxidation. Meanwhile, fatty acid synthase (FAS) expression and activity are markedly inhibited with BA treatment both in vitro and in vivo. Moreover, BA inhibits FAS expression through transcriptional suppression of Yin Yang 1 (YY1), leading to retard hepatocytes triglyceride accumulation. Collectively, BA protects hepatocytes from abnormal lipid deposition in NAFLD through YY1/FAS pathway. Our findings establish a novel role of BA in representing a possible therapeutic strategy to reverse NAFLD.

Inhibition of microRNA-124a attenuates non-alcoholic fatty liver disease through upregulation of adipose triglyceride lipase and the effect of liraglutide intervention.

AIM: Glucagon-like peptide-1 receptor agonists (GLP-1Ras) have been reported to prevent non-alcoholic fatty liver disease (NAFLD), but the potential mechanisms are still debated. MicroRNAs (miRNAs) play a prominent role in the field of metabolic disorders, including NAFLD. Our study was designed to further evaluate the effect of GLP-1Ra liraglutide on NAFLD in terms of miRNAs. METHODS: MicroRNA expression was evaluated by clustering analysis of microRNA arrays in high fat diet-fed mice. The luciferase reporter assay was carried out to validate the cross-talk between adipose triglyceride lipase (ATGL) and miR-124a. MicroRNA-124a mimics and inhibitor plasmids were transfected to study the role of miR-124a in palmitate-treated normal human liver cell line (HL-7702). Liraglutide treatment was used to observe the effect of GLP-1Ra on the miR-124a/ATGL pathway. RESULTS: Expression of ATGL decreased and miR-124a expression increased in hepatosteatosis in vivo and in vitro. Mechanistically, miR-124a interacted with the 3'-untranslated region of ATGL mRNA and induced its degradation. MicroRNA-124a overexpression antagonized the effect of liraglutide on NAFLD by inhibiting ATGL expression, whereas miR-124a knockdown led to elevated ATGL and sirtuin 1 (Sirt1) expression, and subsequently decreased lipid accumulation and inflammation in cells. CONCLUSIONS: MicroRNA-124a overexpression contributes to the progression of NAFLD through reduction of ATGL expression, whereas miR-124a knockdown can reverse this trend, suggesting that miR-124a and its downstream target ATGL can be novel therapeutic targets of NAFLD. We reveal a novel mechanism by which liraglutide attenuates NAFLD by the miR-124a/ATGL/Sirt1 pathway.

Effects of sleep duration and changes in body mass index on diabetic kidney disease: a prospective cohort study.

Aims: To examine the associations of sleep duration and changes in BMI with the onset of diabetic kidney disease (DKD). Materials and methods: 2,959 participants with type 2 diabetes were divided into three groups based on sleep duration: short (<7 h/day), intermediate (7-9 h/day), or long (>9 h/day). Changes in BMI during follow-up were trisected into loss, stable, or gain groups. DKD was defined as either the urinary albumin/creatinine ratio (UACR) ≥ 3.39 mg/mmol or the estimated glomerular filtration rate (eGFR) < 60 mL/min/1.73m², or both. Cox regression models were used to assess hazard ratios (HRs) and 95% confidence intervals (CIs). Results: During a mean follow-up of 2.3 years, DKD occurred in 613 participants (20.7%). A J-shaped curve was observed between sleep duration and DKD. Compared to intermediate sleep duration, long sleep duration was associated with higher risks of DKD (HR 1.47; 95% CI: 1.19-1.81). In the joint analyses, compared to participants with intermediate sleep duration and stable BMI, long sleep duration with BMI gain had the highest risks of DKD (HR 2.04; 95% CI: 1.48-2.83). In contrast, short or intermediate sleep duration accompanied by decrease in BMI was associated with a reduced risk of DKD, with HRs of 0.50 (95% CI: 0.31-0.82) and 0.61 (95% CI:0.47-0.80), respectively. Conclusions: Long sleep duration is significantly associated with an increased risk of DKD, which is further amplified by obesity or BMI gain. These findings suggest that both proper sleep duration and weight control are essential to preventing DKD.

Subclinical atherosclerosis associates with diabetic retinopathy incidence: a prospective study.

BACKGROUND: The prospective correlation between subclinical atherosclerosis and diabetic retinopathy (DR) incidence in Chinese patients with type 2 diabetes mellitus (T2DM) remains elusive. METHODS: Prospective data were obtained from 2781 patients with diabetes, among whom 1,964 and 2,180 T2DM patients without any and referable DR at baseline, respectively, were included in the analysis. Multivariate analyses were performed using the Cox proportional hazards model. RESULTS: Over a median follow-up of 22.2 months (interquartile range 12.7-27.7), 282 (14.36%) and 125 (5.73%) patients developed any and referable DR, respectively. After adjustment for confounders, each standard deviation (SD) increase in brachial-ankle pulse wave velocity (ba-PWV) was associated with 31% (95% confidence interval 1.15-1.50) and 38% (1.14-1.66) higher risks of incident any and referable DR, respectively. Compared with the lowest ba-PWV quartile, the highest ba-PWV quartile had 135% (1.48-3.72) and 293% (1.83-8.44) higher risks of developing any and referable DR, respectively. Per SD increase of pulse pressure (PP) was associated with 22% (1.09-1.38) and 22% (1.02-1.46) higher risks of incident any and referable DR, respectively. The restricted cubic spline models further indicated a significant linear association of baseline subclinical atherosclerosis with referable DR, and a nonlinear association with any DR. In addition, adding the ba-PWV to the prognostic model for DR incidence improved the C-statistic value, the integrated discrimination improvement value, and the net reclassification improvement value (all P < 0.05). CONCLUSIONS: Baseline subclinical atherosclerosis was significantly associated with an increased risk of DR incidence, and elevated ba-PWV independently predicted incident DR in T2DM patients.

MCAD activation by empagliflozin promotes fatty acid oxidation and reduces lipid deposition in NASH.

Medium-chain acyl-CoA dehydrogenase (MCAD) is one of the significant enzymes involved in the ß-oxidation of mitochondrial fatty acids. MCAD deficiency affects the ß-oxidation of fatty acid and leads to lipid deposition in multiple organs, but little is known about its importance in nonalcoholic steatohepatitis (NASH). Empagliflozin is revealed to effectively improve NASH by increasing research, whereas the specific mechanism still has to be explored. Human liver tissues of patients with or without NASH were obtained for proteomic analysis to screen proteins of interest. db/db mice were given empagliflozin by gavage for 8 weeks. The expression of MCAD and signaling molecules involved in hepatic lipid metabolism was evaluated in human liver, mice and HL7702 cells. We found that the MCAD levels in the liver were significantly reduced in NASH patients compared to patients without NASH. Protein-protein interaction network analysis showed that MCAD was highly correlated with forkhead box A2 (FOXA2) and protein kinase AMP-activated catalytic subunit alpha (PRKAA). AMPK/FOXA2/MCAD signaling pathway was detected to be inhibited in the liver of NASH patients. Decreased expression of MCAD was also observed in the livers of db/db mice and hepatocyte treated with palmitic acid and glucose. Of note, empagliflozin could upregulate MCAD expression by activating AMPK/FOXA2 signaling pathway, reduce lipid deposition and improve NASH in vivo and in vitro. This research demonstrated that MCAD is a key player of hepatic lipid deposition and its targeting partially corrects NASH. MCAD thus may be a potential therapeutic target for the treatment of NASH.

Current understanding of the role of Adipose-derived Extracellular Vesicles in Metabolic Homeostasis and Diseases: Communication from the distance between cells/tissues.

Extracellular vesicles (EVs) including exosomes, microvesicles (MVs), and apoptotic bodies, are small membrane vesicular structures that are released during cell activation, senescence, or programmed cell death, including apoptosis, necroptosis, and pyroptosis. EVs serve as novel mediators for long-distance cell-to-cell communications and can transfer various bioactive molecules, such as encapsulated cytokines and genetic information from their parental cells to distant target cells. In the context of obesity, adipocyte-derived EVs are implicated in metabolic homeostasis serving as novel adipokines. In particular, EVs released from brown adipose tissue or adipose-derived stem cells may help control the remolding of white adipose tissue towards browning and maintaining metabolic homeostasis. Interestingly, EVs may even serve as mediators for the transmission of metabolic dysfunction across generations. Also, EVs have been recognized as novel modulators in various metabolic disorders, including insulin resistance, diabetes mellitus, and non-alcoholic fatty liver disease. In this review, we summarize the latest progress from basic and translational studies regarding the novel effects of EVs on metabolic diseases. We also discuss EV-mediated cross-talk between adipose tissue and other organs/tissues that are relevant to obesity and metabolic diseases, as well as the relevant mechanisms, providing insight into the development of new therapeutic strategies in obesity and metabolic diseases.

Sex-influenced association between free triiodothyronine levels and poor glycemic control in euthyroid patients with type 2 diabetes mellitus.

OBJECTIVE: The study investigated the association between free triiodothyronine (FT3) and poor glycemic control with different definitions in euthyroid patients with type 2 diabetes mellitus (T2DM). METHODS: This was a cross-sectional study which included 2172 patients from National Metabolic Management Center in Ruijin Hospital. The association between thyroid function and glycated hemoglobin A1c (HbA1c) was determined by multiple liner regression models. The association between FT3 and poor glycemic control was further determined by binary logistic regression models. Two definitions of poor glycemic control (HbA1c ≥ 7% and HbA1c ≥ 8%) were applied when we analyzed the association. RESULTS: Prevalence of HbA1c ≥ 7% and HbA1c ≥ 8% were 63.8% and 39.3%, respectively. After adjusting for confounding factors, FT3, rather than free tetraiodothyronine (FT4) or thyroid stimulating hormone (TSH), was independently associated with HbA1c (ß = -0.104, P = 0.002). Further analysis after gender stratification showed that the association was only found in males (ß = -0.164, P < 0.001). We further analyzed the association between FT3 quartiles and poor glycemic control. FT3 quartiles were not significantly associated with the risk of HbA1c ≥ 7% before and after adjusting for confounding factors in both genders. FT3 quartiles were negatively associated with the risk of HbA1c ≥ 8% only in males, independent of traditional risk factors for poor glycemic control (P for trend = 0.030). CONCLUSIONS: FT3 in the reference range was significantly associated with reduced risk of HbA1c ≥ 8% in males, independent of traditional risk factors for poor glycemic control.

Liraglutide prevents ß-cell apoptosis via inactivation of NOX2 and its related signaling pathway.

AIMS: High glucose (HG)-induced pancreatic ß-cell apoptosis may be a major contributor to the progression of diabetes mellitus (DM). NADPH oxidase (NOX2) has been considered a crucial regulator in ß-cell apoptosis. This study was designed to evaluate the impact of GLP-1 receptor agonist (GLP-1Ra) liraglutide on pancreatic ß-cell apoptosis in diabetes and the underlying mechanisms involved. METHODS: The diabetic rat models induced by streptozotocin (STZ) and a high fat diet (HFD) received 12 weeks of liraglutide treatment. Hyperglycemic clamp test was carried out to evaluate ß-cell function in vivo. Flow cytometry analysis was used to measure apoptosis rates in vitro. DCFH-DA method was used to detected ROS level in vivo and in vitro. RESULTS: Liraglutide significantly improved islet function and morphology in diabetic rats and decreased cell apoptosis rates. Thr183/Thr185 p-JNK1/2 and NOX2 levels reduced in diabetic rats and HG-induced INS-1 cell following liraglutide treatment. In addition, liraglutide upregulated the phosphorylation of AMPKα (p-AMPKα), which prevented NOX2 activation and alleviated HG-induced ß-cell apoptosis. CONCLUSION: The p-AMPKα/NOX2/JNK1/2 pathway is essential for liraglutide to attenuate HG-induced ß-cell apoptosis, which further proves that GLP-1Ras may become promising therapeutics for diabetes mellitus.

Serum adipocyte fatty acid-binding protein levels are associated with peripheral arterial disease in women, but not men, with type 2 diabetes mellitus.

BACKGROUND: Adipocyte fatty acid-binding protein (A-FABP) has been recognized as an important player in macrophage cholesterol trafficking and inflammation, and may promote the development of atherosclerosis. To further elucidate the role of A-FABP in atherosclerosis in diabetes, we investigated the relationship between serum A-FABP concentrations and peripheral arterial disease (PAD) in patients with type 2 diabetes mellitus (T2DM). METHODS: In all, 488 inpatients with T2DM were enrolled in the study (254 men, 234 women; mean (±SD) age 57.3 ± 13.0 years). The severity of peripheral arterial stenosis was assessed by ultrasound examination. Serum A-FABP concentrations were determined by ELISA. RESULTS: Serum A-FABP concentrations were significantly higher in patients with than without PAD (8.0 ± 3.3 vs 6.2 ± 1.6 ng/mL, respectively; P < 0.05). Interestingly, there was an obvious gender-related difference in PAD patients with T2DM, with the stenosis rate being higher for female than male T2DM patients in the third A-FABP tertile. Logistic regression analysis revealed that serum A-FABP concentrations were an independent risk factor for PAD in female T2DM patients (odds ratio 1.890, 95% confidence interval 1.041-3.432; P = 0.036), but not in male T2DM patients. Correlation analyses revealed that A-FABP concentrations were correlated with body mass index (BMI), diastolic blood pressure, urinary microalbumin, and serum creatinine in male patients, and with BMI, duration of T2DM, fasting blood glucose, and serum creatinine in female patients. CONCLUSIONS: Serum A-FABP concentrations are closely associated with PAD in Chinese women with T2DM. The study findings suggest that A-FABP may be a more specific marker of PAD in diabetic women than men.

Liraglutide attenuates atherosclerosis via inhibiting ER-induced macrophage derived microvesicles production in T2DM rats.

BACKGROUND: We investigated the effects of liraglutide on the formation and progression of atherosclerosis in type 2 diabetes mellitus (T2DM) rats. METHODS: Sprague-Dawley rats were divided into control group, diabetes group and liraglutide treated group. The T2DM rats model with atherosclerosis were induced by high fat diet followed small dosage streptozotocin injection. Body weight and blood glucose levels were monitored once a week for 3 months and then the rats were sacrificed.Peripheral blood and aorta tissues were collected for further biochemical and pathological estimation respectively. Moreover, immunohistochemistry staining was used to detect the infiltration of macrophages and cell apoptosis in tissue samples. The amount of microvesicles of atherosclerotic plaques was determined by ELISA. Western blot was applied to detect the protein expressions of CHOP, GRP78 and caspase-3 in tissue samples. The mRNA expressions of SREBP-1c and FAS were detected by RT-PCR. RESULTS: The rat model of diabetic atherosclerosis was established successfully. Compared with the control group, glucose, triglycerides, total cholesterol, AST, ALT, BUN, fasting insulin and homeostatic model assessment insulin resistance levels in peripheral blood were significantly increased in the diabetes group. While, these indicators in the liraglutide group were significantly lower than that in the diabetes group. Moreover, the atherosclerotic plaques were observed in the rats of diabetes group but not remarkable in the liraglutide group. The ratio between aorta intima and media thickness was significantly greater in the diabetes group than that in the liraglutide group. Compared with the diabetes group, the infiltration and apoptosis of macrophages were milder in the liraglutide group. The expressions of CD68, caspase-3, CHOP and GRP78 in aorta tissue samples were significantly downregulated in the liraglutide group than that in the diabetes group. Furthermore, the microvesicles of aorta tissues in the liraglutide group were significantly decreased than that in the diabetes group. The mRNA expressions of SREBP-1c and FAS were lower in the liraglutide group than that in the diabetes group. CONCLUSION: Liraglutide attenuates diabetic atherosclerosis by inhibition of ER stress and subsequent macrophage apoptosis and microvesicles production in T2DM rats.

Saxagliptin Induces ß-Cell Proliferation through Increasing Stromal Cell-Derived Factor-1α In Vivo and In Vitro.

Dipeptidyl peptidase-4 inhibitors, such as saxagliptin, have been reported to have beneficial effects on ß-cell function, but the specific underlying mechanism remains unclear. Stromal cell-derived factor-1α (SDF-1α), a chemokine produced in multiple organs, has been considered as a crucial regulator in promoting ß-cell survival. Here, we speculate that SDF-1α might mediate the effect of saxagliptin on improving ß-cell function. After 12-week saxagliptin treatment in high-fat diet/streptozotocin-induced diabetic rats, significant improvement in pancreas insulin secretion capacity evaluated by hyperglycemia clamp and increased ß-cell to α-cell areas ratio were observed. Saxagliptin significantly induced ß-cell proliferation and upregulated the expression of proliferation-related factors including c-myc and cyclind D1 determined with western blotting from the isolated islets. The expression/activity of DPP-4 was significantly reduced and paralleled with the restoration of SDF-1α levels in the saxagliptin-treated diabetic rats, subsequently the key WNT-signaling regulators, ß-catenin, and AKT were activated. However, the effect of saxagliptin inducing ß-cell proliferation was attenuated when we silenced the SDF-1α receptor (CXCR4) with RNAi in INS cell lines. Collectively, our data indicate that SDF-1α mediates the protective effect of saxagliptin on ß-cell proliferation, suggesting that DPP-4 inhibitors have the potential role on delaying ß-cell failure and SDF-1α could be a therapeutic target of ß-cell regeneration.