Relationship between insulin resistance and subclinical atherosclerosis in individuals with and without type 2 diabetes mellitus

John Yudkin's hypothesis: sugar is a major dietary culprit in the development of cardiovascular disease

To date, the risk of developing atherosclerosis has extended beyond Western countries and now affecting individuals from various ethnic backgrounds and age groups. Traditional risk factors of atherosclerosis, such as hypercholesterolemia, has been better controlled than before due to highly effective and inexpensive therapies at lowering plasma cholesterol levels. However, the role of reducing dietary cholesterol intake, as a public healthy strategy, in preventing the occurrence of cardiovascular mortalities has been recently challenged. Indeed, despite our continuous decline of dietary cholesterol intake within the last 50 years, the incidence of cardiovascular mortalities has continued to rise, thus raising the possibility that other dietary factors, such as fructose-containing sugars, are the major culprit. In the 1970s, John Yudkin first proposed that sugar was the predominant dietary factor that underlies the majority of cardiovascular mortalities, yet his hypothesis was dismissed. However, over the last 25 years substantial scientific evidence has been accumulated to support Yudkin's hypothesis. The objectives of this review are to highlight Yudkin's significant contribution to nutritional science by reviewing his hypothesis and summarizing the recent advances in our understanding of fructose metabolism. The metabolic consequences of fructose metabolism, such as fructose-induced uricemia, insulin resistance, lipoprotein hyperproduction and chronic inflammation, and how they are linked to atherosclerosis as risk factors will be discussed. Finally, the review will explore areas that warrant future research and raise important considerations that we need to evaluate when designing future studies.

Associations between insulin resistance indices and subclinical atherosclerosis: A contemporary review

Even in the absence of hyperglycemia or hyperlipidemia, it has been demonstrated that insulin resistance is an independent risk factor for atherosclerosis. Finding markers of insulin resistance that are associated with markers of atherosclerosis could help identify patients early in their disease course and allow for earlier initiation of preventative treatments. We reviewed available evidence regarding associations between known markers of insulin resistance and known markers of atherosclerosis. Serum triglycerides (TG), triglyceride-glucose index (TyG), and homeostasis model assessment (HOMA) were the insulin resistance markers reviewed. The coronary artery calcium score (CAC), carotid intimal medium thickness (cIMT), and pulse wave velocity (PWV) were reviewed as markers of atherosclerosis. TyG showed the most consistent association with CAC across broad demographic groups, though HOMA showed potential in obese individuals and those without diabetes. The data regarding cIMT and the reviewed insulin resistance markers did not yield any consistent associations, though very elevated TyG did appear to be associated with cIMT among normal weight individuals. Serum triglycerides showed a strong and consistent association with PWV across numerous studies and populations, though TyG index also demonstrated a strong association with PWV in a large systematic review. Of the insulin resistance markers reviewed, the TyG index appears to be most consistently associated with markers of atherosclerosis. TyG can be easily calculated with routine labwork and has the potential to inform decisions regarding early initiation of therapies in patients who would otherwise not be treated. Targeting insulin sensitivity prior to the development of T2DM has the potential to reduce development and progression of atherosclerosis, and patients without T2DM but who have elevated TyG index should be the topic of further research.

Gut microbiota in insulin resistance: a bibliometric analysis

Background

Insulin resistance (IR) is considered the pathogenic driver of diabetes, and can lead to obesity, hypertension, coronary artery disease, metabolic syndrome, and other metabolic disorders. Accumulating evidence indicates that the connection between gut microbiota and IR. This bibliometric analysis aimed to summarize the knowledge structure of gut microbiota in IR.

Methods

Articles and reviews related to gut microbiota in IR from 2013 to 2022 were retrieved from the Web of Science Core Collection (WoSCC), and the bibliometric analysis and visualization were performed by Microsoft Excel, Origin, R package (bibliometrix), Citespace, and VOSviewer.

Results

A total of 4 749 publications from WoSCC were retrieved, including 3 050 articles and 1 699 reviews. The majority of publications were from China and USA. The University Copenhagen and Shanghai Jiao Tong University were the most active institutions. The journal of Nutrients published the most papers, while Nature was the top 1 co-cited journal, and the major area of these publications was molecular, biology, and immunology. Nieuwdorp M published the highest number of papers, and Cani PD had the highest co-citations. Keyword analysis showed that the most frequently occurring keywords were "gut microbiota", "insulin-resistance", "obesity", and "inflammation". Trend topics and thematic maps showed that serum metabolome and natural products, such as resveratrol, flavonoids were the research hotspots in this field.

Conclusion

This bibliometric analysis summarised the hotspots, frontiers, pathogenesis, and treatment strategies, providing a clear and comprehensive profile of gut microbiota in IR.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40200-023-01342-x.

Association between the homeostasis model assessment of insulin resistance and coronary artery calcification: a meta-analysis of observational studies

Background

Insulin resistance (IR), a risk factor for cardiovascular diseases, has garnered significant attention in scientific research. Several studies have investigated the correlation between IR and coronary artery calcification (CAC), yielding varying results. In light of this, we conducted a systematic review to investigate the association between IR as evaluated by the homeostasis model assessment (HOMA-IR) and CAC.

Methods

A comprehensive search was conducted to identify relevant studies in PubMed, Embase, Scopus, and Web of Science databases. In addition, preprint servers such as Research Square, BioRxiv, and MedRxiv were manually searched. The collected data were analyzed using either fixed or random effects models, depending on the heterogeneity observed among the studies. The assessment of the body of evidence was performed using the GRADE approach to determine its quality.

Results

The current research incorporated 15 studies with 60,649 subjects. The analysis revealed that a higher category of HOMA-IR was associated with a greater prevalence of CAC in comparison to the lowest HOMA-IR category, with an OR of 1.13 (95% CI: 1.06-1.20, I2 = 29%, P < 0.001). A similar result was reached when HOMA-IR was analyzed as a continuous variable (OR: 1.27, 95% CI: 1.14-1.41, I2 = 54%, P < 0.001). In terms of CAC progression, a pooled analysis of two cohort studies disclosed a significant association between increased HOMA-IR levels and CAC progression, with an OR of 1.44 (95% CI: 1.04-2.01, I2 = 21%, P < 0.05). It is important to note that the strength of the evidence was rated as low for the prevalence of CAC and very low for the progression of CAC.

Conclusion

There is evidence to suggest that a relatively high HOMA-IR may be linked with an increased prevalence and progression of CAC.

Triglyceride-glucose index is associated with recurrent revascularization in patients with type 2 diabetes mellitus after percutaneous coronary intervention

BACKGROUND

The Triglyceride-glucose (TyG) index, as a surrogate marker of insulin resistance, is independently associated with the severity of coronary artery lesions and the prognosis of coronary heart disease. The investigation aimed to explore the relationship between the TyG index and recurrent revascularization in individuals with type 2 diabetes mellitus (T2DM) resulting from the progression of lesions or in-stent restenosis (ISR) after percutaneous coronary intervention (PCI).

METHOD

A total of 633 patients who met the inclusion and exclusion criteria were enrolled and divided into three groups based on the tertiles of the TyG index. The primary endpoint was recurrent revascularization resulting from the progression of lesions or ISR. All-cause death was considered as the competing risk event. Competing risk analysis and Cox regression analysis for predicting recurrent revascularization after PCI were conducted stepwise. Variables were standardized to make the hazard ratio (HR), subdistribution hazard ratio (SHR) and corresponding 95% CI more consistent prior to being used for fitting the multivariate risk model. The predictive ability of the TyG index was evaluated using several measures, including the ROC curve, likelihood ratio test, Akaike's information criteria, category-free continuous net reclassification improvement (cNRI > 0), and integrated discrimination improvement (IDI). Internal validation was conducted through bootstrapping with 1000 resamples.

RESULTS

During a median follow-up period of 18.33 months, a total of 64 (10.11%) patients experienced recurrent revascularization, including 55 cases of lesion progression and 9 cases of in-stent restenosis. After controlling for competitive risk events, the TyG index was independently associated with a higher risk of recurrent revascularization [SHR:1.4345, (95% CI 1.1458-1.7959), P = 0.002]. The likelihood ratio test and Akaike's information criteria showed that the TyG index significantly improves the prognostic ability. Additionally, adding the TyG index improved the ability of the established risk model in predicting recurrent revascularization, indicated by a C-index of 0.759 (95% CI 0.724-0.792, P < 0.01), with a cNRI > 0 of 0.170 (95% CI 0.023-0.287, P < 0.05), and an IDI of 0.024 (95% CI 0.009-0.039, P = 0.002). These results remained consistent when the models containing TyG index were confirmed using an internal bootstrap validation method.

CONCLUSION

The findings highlight the potential of the TyG index as a predictor of recurrent revascularization. Lesion progression emerged as the primary contributor to recurrent revascularization instead of in-stent restenosis. The incorporation of the TyG index into risk prediction models is likely to be beneficial for accurate risk stratification in order to improve prognosis.

Risk Factors for Coronary Artery Calcifications in Overweight or Obese Persons with Prediabetes: Can They Predict T2 Diabetes and Coronary Vascular Events?

BACKGROUND

It is difficult to predict the risk of developing atherosclerotic cardiovascular disease in subjects with prediabetes and obesity. The aim of this study was to assess risk factors for coronary artery calcifications (CACs) and the development of type 2 diabetes (T2D) and coronary vascular events (CVEs) after 7 years in 100 overweight or obese persons with prediabetes, according to the baseline coronary artery calcium score (CACS).

METHODS

Lipids, HbA1c, uric acid, and creatinine were assessed. Glucose, insulin, and c-peptide were determined during an oral glucose tolerance test. Multi-sliced computerized tomography with evaluation of CACS was performed. After 7 years, the subjects were assessed for T2D/CVE.

RESULTS

CACs were present in 59 subjects. No single biochemical marker could predict presence of a CAC. After 7 years, T2D developed in 55 subjects (61.8% initially had both IFG and IGT). A gain in weight was the only contributing factor for T2D. Nineteen subjects developed a CVE; increased initial clustering of HOMA-IR > 1.9, LDL > 2.6, and mmol/Land TGL > 1.7 mmol/L and higher CACS were present in that group.

CONCLUSIONS

No risk factors for CACs could be identified. A gain in weight is associated with T2D development, as are higher CACS and clustering of high LDL+TGL+HOMA-IR with CVEs.

Adipokine-Cytokine Profile in Patients with Unstable Atherosclerotic Plaques and Abdominal Obesity

The goal of the research was to study the levels of adipokines and their associations with unstable atherosclerotic plaques in patients with coronary atherosclerosis and abdominal obesity (AO).

METHODS

The study included 145 men aged 38-79 with atherosclerosis of the coronary arteries (CA) and stable angina pectoris II-III FC who were hospitalized for coronary bypass surgery (2011-2022). The final analysis included 116 patients. Notably, 70 men had stable plaques in the CA (of which 44.3% had AO), and 46 men had unstable plaques in the CA (of which 43.5% had AO). Adipocytokine levels were determined using multiplex analysis (Human Metabolic Hormone V3 panel).

RESULTS

In the subgroup of patients with unstable plaques, patients with AO had a GLP-1 level that was 1.5 times higher and a lipocalin-2 level that was 2.1 times lower, respectively. GLP-1 is direct, and lipocalin-2 is inversely associated with AO in patients with unstable plaques. Among patients with AO, the level of lipocalin-2 in patients with unstable plaques was 2.2 times lower than in patients with stable plaques in the CA. The level of lipocalin-2 was inversely associated with the presence of unstable atherosclerotic plaques in the CA.

CONCLUSION

GLP-1 is directly associated with AO in patients with unstable atherosclerotic plaques. Lipocalin-2 is inversely associated with unstable atherosclerotic plaques in patients with AO.

Periodontitis and implant complications in diabetes

Epidemiologic evidence indicates that periodontitis is more frequent in patients with uncontrolled diabetes mellitus than in healthy controls, suggesting that it could be considered the "sixth complication" of diabetes. Actually, diabetes mellitus and periodontitis are two extraordinarily prevalent chronic diseases that share a number of comorbidities all converging toward an increased risk of cardiovascular disease. Periodontal treatment has recently been shown to have the potential to improve the metabolic control of diabetes, although long-term studies are lacking. Uncontrolled diabetes also seems to affect the response to periodontal treatment, as well as the risk to develop peri-implant diseases. Mechanisms of associations between diabetes mellitus and periodontal disease include the release of advanced glycation end products as a result of hyperglycemia and a range of shared predisposing factors of genetic, microbial, and lifestyle nature. This review discusses the evidence for the risk of periodontal and peri-implant disease in diabetic patients and the potential role of the dental professional in the diabetes-periodontal interface.

Anti-Atherosclerotic Effect of Gossypetin on Abnormal Vascular Smooth Muscle Cell Proliferation and Migration

Gossypetin (GTIN), known as 3,5,7,8,3′,4′-hexahydroxyflavone, has been demonstrated to exert anti-atherosclerotic potential against apoptotic injury in oxidized low-density lipoprotein-incubated endothelial cells, and atherosclerotic lesions of cholesterol-fed rabbits. However, the effect and underlying mechanism of GTIN on abnormal vascular smooth muscle cells (VSMCs) proliferation and migration, a major event in the pathogenesis of atherosclerosis, is still unknown. In this study, non-cytotoxic doses of GTIN abolished the VSMCs A7r5 proliferation and cell-cycle S phase distribution. The GTIN-arrested G0/G1 phase might be performed by increasing the expressions of phosphorylated p53 and its downstream molecules that inhibit the activation of cyclin E/cyclin-dependent kinase (cdk)-2, blocking retinoblastoma protein (Rb) phosphorylation and the subsequent dissociation of Rb/transcription factor E2F1 complex. In addition, the results indicated that GTIN inhibited VSMCs wound-healing and migratory abilities through reducing matrix metalloproteinase (MMP)-9 activity and expression, as well as down-regulating protein kinase B (PKB)/nuclear factor-kappaB (NF-κB) signaling. GTIN also revealed potential in diminishing reactive oxygen species (ROS) generation. These findings suggested the inhibitory effects of GTIN on VSMCs dysfunction could likely lead to the containment of atherosclerosis and other cardiovascular illness.

A Cardiac Protection of Germinated Brown Rice During Cardiopulmonary Bypass Surgery and Simulated Myocardial Ischemia

Purpose

The potential cardio-protective property of germinated brown rice (GBR) has been revealed by ameliorating risk factors related to cardiovascular diseases. This study hypothesized that the combination of GBR and cardioplegic solution could protect the cardiomyocytes exposed to simulated ischemic reperfusion injury in vitro study and preserve cardiac function during cardiopulmonary bypass surgery in animal models.

Methods

Primary porcine cardiomyocytes were isolated and experimented cell viability against simulated ischemic reperfusion injury. In a cardiac surgical animal model, six pigs were randomly assigned to receive the two types of cardioplegic solution: i) St. Thomas cardioplegic solution (20 cc/kg); and ii) St. Thomas cardioplegic solution plus GBR (1 mg/kg). During open-heart surgery, the aorta was cross-clamped for 20 minutes, followed by reperfusion for 1 hour. Cardiopulmonary bypass parameters were recorded until the end of the procedure. Furthermore, hemodynamic parameters and arterial blood gas characteristics of animals among groups were monitored at different time points, including baseline before cardiopulmonary bypass (T1), during cardiopulmonary bypass (T2), during aortic clamp on (T3), and aortic clamp off (T4).

Results

Primarily, GBR cotreatment with cardioplegic solution essentially resulted in the improvement of cell viability in primary porcine cardiomyocytes against simulated ischemic reperfusion induction. The findings from cardiac surgery demonstrated that mean arterial pressure and heart rate are constantly stable in cardioplegic solution combined with the GBR group, while the trend of potassium and lactase concentration was decreased in the animals receiving GBR group. Consistently, all parameters from arterial blood gas showed better outcomes in animals receiving GBR; however, there were no statistically significant differences between groups, except hepatic enzymes.

Conclusion

Therefore, GBR might exert cardio-protective effects against ischemic reperfusion injury in the porcine cardiac surgery model due to anti-inflammatory response. These protective actions of GBR may explain the benefits gained from applying GBR products as a possible therapeutic supplement on cardiac diseases.

Cardiac protection of germinated brown rice extract in rabbit model of chronic myocardial infarction

Ischemic heart disease is a leading cause of mortality in the world. This study aimed to investigate the cardioprotective effects of germinated brown rice (GBR) on a rabbit model of chronic myocardial infarction. Eighteen New Zealand white rabbits were randomly divided into three groups receiving: 1) regular rabbit food; 2) regular rabbit food plus vehicle; and 3) regular rabbit food plus GBR for 120 d. The left circumflex coronary artery was ligated to induce myocardial ischemia 60 d after starting the experiment (baseline). Heart functions were monitored by electrocardiography and echocardiography at 0, 30, and 60 d after coronary artery ligation. The incidences of heart rate (HR) and ventricular arrhythmias have been compared between groups. GBR showed the effects to prevent life-threatening ventricular tachycardia and electrocardiographic signs of myocardial ischemia in a model of arrhythmias. GBR consumption group exhibited significantly improved cardiac function and reduced the HR, along with reduced mean arterial pressure and plasma glucose level. The results demonstrated that GBR exerts cardioprotective effects against chronic myocardial injury in rabbits. These biological actions of GBR may explain the benefits gained from the use of GBR products as a possible prophylactic lifestyle intervention.

Common Variants in IL-20 Gene are Associated with Subclinical Atherosclerosis, Cardiovascular Risk Factors and IL-20 Levels in the Cohort of the Genetics of Atherosclerotic Disease (GEA) Mexican Study

Inflammation has been involved in the development of atherosclerosis, type 2 diabetes mellitus, insulin resistance, and obesity. Interleukin 20 is a pro-inflammatory cytokine encoded by a polymorphic gene located in chromosome 1. The aim of the study was to evaluate the association of two IL-20 polymorphisms (rs1400986 and rs1518108) with subclinical atherosclerosis (SA), cardiovascular risk factors and IL-20 levels in a cohort of Mexican individuals. The polymorphisms were determined in 274 individuals with SA and 672 controls. Under different models, rs1400986 (OR = 0.51, P_codominant1 = 0.0001; OR = 0.36, P_codominant2 = 0.014; OR = 0.49, P_dominant = 0.0001 and OR = 0.55, P_additive = 0.0001) and rs1518108 (OR = 0.62, P_codominant2 = 0.048 and OR = 0.79, P_additive = 0.048) were associated with a lower risk of SA. These polymorphisms were associated with cardiovascular risk factors in individuals with SA and controls. Controls with the rs1400986 TT genotype presented high levels of IL-20 (p = 0.031). In individuals with the rs1400986 CC genotype, we observed a negative correlation between IL-20 levels and total abdominal tissue (TAT), visceral abdominal tissue (VAT) and subcutaneous abdominal tissue (SAT). Our results indicate that the IL-20 rs1400986 and rs1518108 polymorphisms were associated with decreased risk of developing SA and with some cardiovascular risk factors in individuals with SA and healthy controls. Negative correlation between BMI and VAT/SAT ratio in individuals with rs1400986 CC genotype and among IL-20 levels and TAT, VAT and SAT was observed.

Insulin Resistance and Atherosclerosis: Implications for Insulin-Sensitizing Agents

Patients with type 2 diabetes mellitus (T2DM) are at high risk for macrovascular complications, which represent the major cause of mortality. Despite effective treatment of established cardiovascular (CV) risk factors (dyslipidemia, hypertension, procoagulant state), there remains a significant amount of unexplained CV risk. Insulin resistance is associated with a cluster of cardiometabolic risk factors known collectively as the insulin resistance (metabolic) syndrome (IRS). Considerable evidence, reviewed herein, suggests that insulin resistance and the IRS contribute to this unexplained CV risk in patients with T2DM. Accordingly, CV outcome trials with pioglitazone have demonstrated that this insulin-sensitizing thiazolidinedione reduces CV events in high-risk patients with T2DM. In this review the roles of insulin resistance and the IRS in the development of atherosclerotic CV disease and the impact of the insulin-sensitizing agents and of other antihyperglycemic medications on CV outcomes are discussed.

The impact of provision of self-monitoring of blood glucose supplies on self-care activities among patients with uncontrolled Type 2 diabetes mellitus: A prospective study

AIMS

Self-monitoring of blood glucose (SMBG) is an important self-care activity for patients with Type 2 diabetes mellitus (T2DM) to achieve glycaemic control. The aim of this study was to evaluate the impact of providing SMBG supplies on self-care among patients with uncontrolled T2DM.

METHODS

This was a six-month, prospective study conducted in two primary care institutions. Patients ≥21 years old with uncontrolled T2DM (HbA1c > 7.0%) and polypharmacy (≥5 chronic medications) were included. All participants were given a free blood glucometer, test strips, and lancets, and were invited to consult pharmacists to learn about SMBG. The Summary of Diabetes Self-Care Activities questionnaire was administered at baseline and at six months.

RESULTS

A total of 167 patients were recruited and 150 (89.8%) completed the study. At six months, significant improvements from baseline were observed for overall self-care (+0.58, p = 0.008), glycemic control (-0.41%, p < 0.001) and all specific self-care activities. The mean change in the SMBG score in all the participants was found to have a strong positive correlation with the mean change in the overall self-care score (r_s = 0.580, p = 0.01).

CONCLUSIONS

Provision of SMBG supplies was effective in improving self-care among patients with uncontrolled T2DM, including non-insulin-treated patients.

Relationships Between Skin Autofluorescence and Cardio-Ankle Vascular Index in Japanese Male Patients With Metabolic Syndrome

Background

An autofluorescence (AF) reader can be used to noninvasively measure tissues that accumulated advanced glycation end-products to diagnose skin AF. This study aimed to clarify the clinical significance of skin AF as a risk factor for cardiovascular disease in Japanese male patients with metabolic syndrome using the cardio-ankle vascular index (CAVI) as a marker of arterial function.

Methods

This cross-sectional study enrolled 261 Japanese male patients with metabolic syndrome without history of cardiovascular disease (mean age, 58 ± 7 years (mean ± standard deviation)). Associations between skin AF and various clinical parameters including CAVI were examined.

Results

Skin AF was significantly positively correlated with CAVI (r = 0.40, P < 0.001). Furthermore, multiple regression analyses revealed that skin AF (β = 0.18, P = 0.002) was selected as an independent subordinate factor for CAVI. Meanwhile, homeostatic model assessment of insulin resistance (HOMA-IR) as a marker of insulin resistance, smoking habits and high-sensitivity C-reactive protein as an inflammation marker were independent variables for either CAVI or skin AF as a subordinate factor. According to the receiver-operating characteristic curve analysis and results of previous reports that determined CAVI of ≥ 9.0 as a diagnostic criterion for vascular failure, skin AF of > 2.7 arbitrary unit is the optimal cut-off point for discriminating high CAVI (area under the curve = 0.718, P < 0.001).

Conclusion

Findings in this study indicate that skin AF may be an important risk factor of cardiovascular disease in Japanese male patients with metabolic syndrome. In addition, the risk value of skin AF was considered as higher than 2.7 arbitrary unit. Further investigations in a large number of prospective studies, including intervention therapies, are required to validate the results in this study.

The continuums of impairment in vascular reactivity across the spectrum of cardiometabolic health: A systematic review and network meta-analysis

This study aimed to assess, for the first time, the change in vascular reactivity across the full spectrum of cardiometabolic health. Systematic searches were conducted in MEDLINE and EMBASE databases from their inception to March 13, 2017, including studies that assessed basal vascular reactivity in two or more of the following health groups (aged ≥18 years old): healthy, overweight, obesity, impaired glucose tolerance, metabolic syndrome, or type 2 diabetes with or without complications. Direct and indirect comparisons of vascular reactivity were combined using a network meta-analysis. Comparing data from 193 articles (7226 healthy subjects and 19344 patients), the network meta-analyses revealed a progressive impairment in vascular reactivity (flow-mediated dilation data) from the clinical onset of an overweight status (-0.41%, 95% CI, -0.98 to 0.15) through to the development of vascular complications in those with type 2 diabetes (-4.26%, 95% CI, -4.97 to -3.54). Meta-regressions revealed that for every 1 mmol/l increase in fasting blood glucose concentration, flow-mediated dilation decreased by 0.52%. Acknowledging that the time course of disease may vary between patients, this study demonstrates multiple continuums of vascular dysfunction where the severity of impairment in vascular reactivity progressively increases throughout the pathogenesis of obesity and/or insulin resistance, providing information that is important to enhancing the timing and effectiveness of strategies that aim to improve cardiovascular outcomes.

Pioglitazone/microRNA‑141/FOXA2: A novel axis in pancreatic β‑cells proliferation and insulin secretion

MicroRNAs (miRs) are considered to be effective, post‑transcriptional regulators in the pathophysiology of type 2 diabetes (T2D) and promising treatment targets. However, the function of miR‑141 remains to be elucidated. In the present study, upregulation of miR‑141 was demonstrated in diabetic mice and elderly diabetic patients. Using reverse transcriptase‑quantitative polymerase chain reaction, luciferase reporter assays and western blotting, forkhead box A2 (FOXA2) was identified as a direct target gene of miR‑141. The potential role of miRNA‑141 or FOXA2 was evaluated by overexpressing or silencing miR‑141 or FOXA2, respectively. The increased expression of miR‑141 resulted in impaired glucose‑stimulated insulin secretion (GSIS) and INS‑1 β cell proliferation. In addition, miR‑141 silencing in MIN6 pseudoislets or INS‑1 β cells led to reduced T2D‑associated damage. Furthermore, the expression of miR‑141 may be corrected by treatment with pioglitazone, which is widely used for insulin resistance therapy. The present study also demonstrated the mechanism by which miR‑141 regulated GSIS and proliferation through FOXA2. Overexpression of FOXA2 in MIN6 pseudoislets increased the effect of the miR‑141 inhibitor on GSIS. FOXA2 effectively reversed the effect of miR‑141 overexpression on β cell proliferation. In conclusion, the results of the present study indicate that the pioglitazone/miR‑141/FOXA2 axis may represent a promising target mechanism for T2D treatment.

Acarbose inhibits the proliferation and migration of vascular smooth muscle cells via targeting Ras signaling

Atherosclerosis involves the proliferation and migration of vascular smooth muscle cells (VSMCs). The migration of VSMCs from the media into the intima and their subsequent proliferation are important processes in neointima formation in atherosclerosis and restenosis after percutaneous coronary interventions. Acarbose, an alpha-glucosidase inhibitor, has been demonstrated to not affect serum levels of glucose and decrease the progression of intima-media thickening in rabbits fed with a high cholesterol diet (HCD). We previously showed that increased Ras protein levels enhanced the migration of TNF-α treated A7r5 cells. The aim of this study was to determine the inhibitory effects of acarbose on Ras expression in A7r5 cells. Acarbose also inhibited the phosphorylation of focal adhesion kinase (FAK) and Akt, activities of the matrix metalloproteinases (MMPs) MMP-2 and MMP-9, and protein expressions of small G proteins (Ras, Cdc42, RhoA, and Rac1) in a dose-dependent manner. We also found that acarbose could effectively inhibit the proliferation and migration of Ras^G12V A7r5 cells by blocking small G proteins and phosphoinositide-3-kinase (PI3K)/Akt signaling. These studies demonstrated that acarbose could theoretically decrease atherosclerosis by targeting Ras signaling.

The association between insulin resistance, metabolic syndrome, and ischemic heart disease among Rumoi residents

Background

It has widely been proven that metabolic syndrome (MetS) increases the risk of ischemic heart disease (IHD). MetS is confirmed based upon insulin resistance (IR). Our aim of this study is to evaluate the role of MetS and IR in the prediction of IHD incidence.

Methods

A total of 404 non‐diabetic participants who underwent 75 g oral glucose tolerance test (75 g OGTT) were enrolled from 2001 to 2009. Risk factors for IHD were measured as well. The homeostatic index of IR (HOMA‐IR) and the homeostatic model assessment beta cell function (HOMA‐β) were calculated according to the homeostasis model assessment. Cox proportional‐hazard regression model was used to estimate hazard ratio (HR). All data were analyzed using SPSS 21 software (IBM, Armonk, NY, USA).

Results

In our study, the average follow‐up period was 6.7 years. Eighteen subjects of IHD incidence were recorded. After adjusting for age and sex, subjects with IR or hyperinsulinemia had a high risk of IHD, the hazard ratio (95% confidence intervals) for IHD were 4.58 (1.59‐13.15), 4.25 (1.64‐11.91), respectively. The highest hazard ratio was 7.56 (2.27‐25.18) which was found among the subjects with both IR and hyperinsulinemia. In addition, the hazard ratio (95% confidence intervals) of subjects with MetS was 2.80(1.10‐7.09).

Conclusions

IR and hyperinsulinemia are related to the risk of IHD. IR combined with hyperinsulinemia may be superior to MetS for predicting the IHD incidence.

The Combination Therapy of Fenofibrate and Ezetimibe Improved Lipid Profile and Vascular Function Compared with Statins in Patients with Type 2 Diabetes

AIM

Elevated level of serum triglyceride (TG) is a characteristic of type 2 diabetes. We evaluated the clinical significance of intervention for the serum TG levels in the fasting and postprandial states in patients with type 2 diabetes.

METHODS

Fifty patients with type 2 diabetes, treated with statins, were selected and divided into two groups. One group was treated with a combination of fenofibrate and ezetimibe (F/E group) and the other group with statins (statin group) for 12 weeks. The lipoprotein profile of both groups was compared using high-performance liquid chromatography, and the vascular function was assessed using flow-mediated dilation (FMD) at the forearm.

RESULTS

The levels of very low-density lipoprotein (VLDL) cholesterol, malondialdehyde low-density lipoprotein (MDA-LDL), total TG, chylomicron-TG, VLDL-TG, and HDL-TG decreased in the F/E group, whereas those of HDL cholesterol increased. Furthermore, the peak particle size of LDL increased, but that of HDL decreased in the F/E group. The combination treatment significantly improved the FMD. The change in the cholesterol level in a very small fraction of HDL was a significant independent predictor for determining the improvement of FMD (p＜0.01).

CONCLUSIONS

Compared with the treatment with statins, the treatment with the combination of fenofibrate and ezetimibe effectively controlled the LDL cholesterol and TG levels, increased the HDL cholesterol level, especially in its small fraction, and improved vascular function of patients with type 2 diabetes.