Molecular mechanisms of insulin resistance that impact cardiovascular biology

Sex-specific association between triglyceride-glucose index and all-cause mortality in patients with osteoporotic fractures: a retrospective cohort study

Background

Osteoporotic fractures (OPFs) pose a considerable global health burden and are linked with an elevated mortality risk. The triglyceride-glucose index (TyG-I) is a recognized marker of insulin resistance across various populations. The association between all-cause mortality (ACM) and the TyG-I has been widely investigated in a variety of clinical settings. The potential sex-specific differences in this association among OPF patients remain uncertain.

Methods

In this retrospective cohort study, 2,307 patients ≥ 50 years old admitted to the hospital between January 2018 and August 2023 for surgical treatment of OPFs were included. The TyG-I was determined using fasting triglyceride and glucose levels measured at admission. The association between ACM and the TyG-I was evaluated by Cox proportional hazards regression, adjusting for possible confounding variables. Analyses were categorized by sex, and subgroup analyses evaluated possible interaction effects. The ACM rates among TyG-I tertiles were compared via Kaplan-Meier curves.

Results

This research study analyzed 2,307 patients, of whom 247 (10.71%) died from any cause during the follow-up period. In females, a linear association of the TyG-I with ACM was observed even after adjusting for confounders, with each unit increase in the TyG-I correlating with a 37% increased risk of death (HR: 1.37, 95% CI: 1.06-1.77, p = 0.02). However, in males, there was a non-linear correlation, where patients in the uppermost TyG-I tertile showed a substantially decreased mortality risk relative to those in the lowest tertile (HR: 0.53, 95% CI: 0.30-0.92, p = 0.02). TyG-I indicated a statistically significant relation with sex (P for interaction = 0.01).

Conclusion

In patients diagnosed with OPFs, distinct sex-specific variations were observed in the relationship between ACM and the TyG-I. Among female patients, each unit increase in the TyG-I was linked to a 37% greater risk of mortality. Conversely, male patients within the highest TyG-I tertile indicated a lower mortality risk than those in the lowest tertile. Further research is required to confirm these sex-specific associations.

Targeting Diabetic Atherosclerosis: The Role of GLP-1 Receptor Agonists, SGLT2 Inhibitors, and Nonsteroidal Mineralocorticoid Receptor Antagonists in Vascular Protection and Disease Modulation

Atherosclerosis is a closely related complication of diabetes mellitus (DM), driven by endothelial dysfunction, inflammation, and oxidative stress. The progression of atherosclerosis is accelerated by hyperglycemia, insulin resistance, and hyperlipidemia. Novel antidiabetic agents, SGLT2 inhibitors, and GLP-1 agonists improve glycemic control and offer cardiovascular protection, reducing the risk of major adverse cardiovascular events (MACEs) and heart failure hospitalization. These agents, along with nonsteroidal mineralocorticoid receptor antagonists (nsMRAs), promise to mitigate metabolic disorders and their impact on endothelial function, oxidative stress, and inflammation. This review explores the potential molecular mechanisms through which these drugs may prevent the development of atherosclerosis and cardiovascular disease (CVD), supported by a summary of preclinical and clinical evidence.

NOD1: a metabolic modulator

Nucleotide-binding oligomerization domain 1 (NOD1) is an intracellular pattern recognition receptor that detects injury signals and initiates inflammatory responses and host defense. Furthermore, NOD1 serves as a metabolic mediator by influencing the metabolism of various tissues, including adipose tissue, liver, cardiovascular tissue, pancreatic β cells, adrenal glands, and bones through diverse mechanisms. It has been discovered that activated NOD1 is associated with the pathological mechanisms of certain metabolic diseases. This review presents a comprehensive summary of the impact of NOD1 on tissue-specific metabolism.

Deciphering interleukin-18 in diabetes and its complications: Biological features, mechanisms, and therapeutic perspectives

Interleukin-18 (IL-18), a potent and multifunctional pro-inflammatory cytokine, plays a critical role in regulating β-cell failure, β-cell death, insulin resistance, and various complications of diabetes mellitus (DM). It exerts its effects by triggering various signaling pathways, enhancing the production of pro-inflammatory cytokines and nitric oxide (NO), as well as promoting immune cells infiltration and β-cells death. Abnormal alterations in IL-18 levels have been revealed to be strongly associated with the onset and development of DM and its complications. Targeting IL-18 may present a novel and promising approach for DM therapy. An increasing number of IL-18 inhibitors, including chemical and natural inhibitors, have been developed and have been shown to protect against DM and diabetic complications. This review provides a comprehensive understanding of the production, biological functions, action mode, and activated signaling pathways of IL-18. Next, we shed light on how IL-18 contributes to the pathogenesis of DM and its associated complications with links to its roles in the modulation of β-cell failure and death, insulin resistance in various tissues, and pancreatitis. Furthermore, the therapeutic potential of targeting IL-18 for the diagnosis and treatment of DM is also highlighted. We hope that this review will help us better understand the functions of IL-18 in the pathogenesis of DM and its complications, providing novel strategies for DM diagnosis and treatment.

Insulin resistance assessed by estimated glucose disposal rate and risk of atherosclerotic cardiovascular diseases incidence: the multi-ethnic study of atherosclerosis

BACKGROUND

To investigate the relationship between estimated glucose disposal rate (eGDR), a surrogate indicator of insulin resistance, and atherosclerotic cardiovascular diseases (ASCVD) incidence risk.

METHODS

This prospective cohort study utilized data from the 6026 participants from the Multi-Ethnic Study of Atherosclerosis. The eGDR (mg/kg/min) was computed as 21.158 - (0.09 × waist circumference [cm]) - (3.407 × hypertension [yes/no]) - (0.551 × HbA1c [%]). The population was categorized into four subgroups according to the quartiles (Q) of eGDR. Cox proportional hazard models were applied to assess the associations between eGDR and ASCVD incidence, and restricted cubic spine (RCS) was employed to examine the dose-response relationship.

RESULTS

The mean age of participants was 63.6 ± 10.1 years, comprising 3163 (52.5%) women. Over a median follow-up duration of 14.1 years, 565 (9.4%) developed ASCVD, including 256 (4.2%) myocardial infarctions, 234 (3.9%) strokes, and 358 (5.9%) fatal coronary heart disease. Compared to the lowest quartile, the adjusted hazard ratios (95% confidence intervals) for incident ASCVD for Q2-Q4 were 0.87 (0.68-1.10), 0.63 (0.47-0.84), and 0.43 (0.30-0.64), respectively. Per 1 standard deviation increase in eGDR was associated with a 30% (HR: 0.70, 95% CI 0.60-0.80) risk reduction of ASCVD, with the subgroup analyses indicating that age and hypertension modified the association (P for interaction < 0.05). RCS analysis indicated a significant and linear relationship between eGDR and ASCVD incidence risk.

CONCLUSION

eGDR level was negatively associated with incident ASCVD risk in a linear fashion among the general population. Our findings may contribute to preventive measures by improving ASCVD risk assessment.

Relation Between Obesity and Type 2 Diabetes: Evolutionary Insights, Perspectives and Controversies

PURPOSE OF REVIEW

Since the mid-twentieth century, obesity and its related comorbidities, notably insulin resistance (IR) and type 2 diabetes (T2D), have surged. Nevertheless, their underlying mechanisms remain elusive. Evolutionary medicine (EM) sheds light on these issues by examining how evolutionary processes shape traits and diseases, offering insights for medical practice. This review summarizes the pathogenesis and genetics of obesity-related IR and T2D. Subsequently, delving into their evolutionary connections. Addressing limitations and proposing future research directions aims to enhance our understanding of these conditions, paving the way for improved treatments and prevention strategies.

RECENT FINDINGS

Several evolutionary hypotheses have been proposed to unmask the origin of obesity-related IR and T2D, e.g., the "thrifty genotype" hypothesis suggests that certain "thrifty genes" that helped hunter-gatherer populations efficiently store energy as fat during feast-famine cycles are now maladaptive in our modern obesogenic environment. The "drifty genotype" theory suggests that if thrifty genes were advantageous, they would have spread widely, but proposes genetic drift instead. The "behavioral switch" and "carnivore connection" hypotheses propose insulin resistance as an adaptation for a brain-dependent, low-carbohydrate lifestyle. The thrifty phenotype theory suggests various metabolic outcomes shaped by genes and environment during development. However, the majority of these hypotheses lack experimental validation. Understanding why ancestral advantages now predispose us to diseases may aid in drug development and prevention of disease. EM helps us to understand the evolutionary relation between obesity-related IR and T2D. But still gaps and contradictions persist. Further interdisciplinary research is required to elucidate complete mechanisms.

Acute Hyperglycemia-Induced Injury in Myocardial Infarction

Acute hyperglycemia is a transient increase in plasma glucose level (PGL) frequently observed in patients with ST-elevation myocardial infarction (STEMI). The aim of this review is to clarify the molecular mechanisms whereby acute hyperglycemia impacts coronary flow and myocardial perfusion in patients with acute myocardial infarction (AMI) and to discuss the consequent clinical and prognostic implications. We conducted a comprehensive literature review on the molecular causes of myocardial damage driven by acute hyperglycemia in the context of AMI. The negative impact of high PGL on admission recognizes a multifactorial etiology involving endothelial function, oxidative stress, production of leukocyte adhesion molecules, platelet aggregation, and activation of the coagulation cascade. The current evidence suggests that all these pathophysiological mechanisms compromise myocardial perfusion as a whole and not only in the culprit coronary artery. Acute hyperglycemia on admission, regardless of whether or not in the context of a diabetes mellitus history, could be, thus, identified as a predictor of worse myocardial reperfusion and poorer prognosis in patients with AMI. In order to reduce hyperglycemia-related complications, it seems rational to pursue in these patients an adequate and quick control of PGL, despite the best pharmacological treatment for acute hyperglycemia still remaining a matter of debate.

Differential miRNA and Protein Expression Reveals miR-1285, Its Targets TGM2 and CDH-1, as Well as CD166 and S100A13 as Potential New Biomarkers in Patients with Diabetes Mellitus and Pancreatic Adenocarcinoma

Early detection of PDAC remains challenging due to the lack of early symptoms and the absence of reliable biomarkers. The aim of the present project was to identify miRNA and proteomics signatures discriminating PDAC patients with DM from nondiabetic PDAC patients. Proteomics analysis and miRNA array were used for protein and miRNA screening. We used Western blotting and Real-Time Quantitative Reverse Transcription polymerase chain reaction (qRT-PCR) for protein and miRNA validation. Comparisons between experimental groups with normal distributions were performed using one-way ANOVA followed by Tukey's post hoc test, and pairwise tests were performed using t-tests. p ≤ 0.05 was considered statistically significant. Protein clusters of differentiation 166 (CD166), glycoprotein CD63 (CD63), S100 calcium-binding protein A13 (S100A13), and tumor necrosis factor-β (TNF-β) were detected in the proteomics screening. The miRNA assay revealed a differential miRNA 1285 regulation. Previously described target proteins of miR-1285 cadherin-1 (CDH-1), cellular Jun (c-Jun), p53, mothers against decapentaplegic homolog 4 (Smad4), human transglutaminase 2 (TGM2) and yes-associated protein (YAP), were validated via Western blotting. miR-1285-3p was successfully validated as differentially regulated in PDAC + DM via qRT-PCR. Overall, our data suggest miRNA1285-3p, TGM2, CDH-1, CD166, and S100A13 as potential meaningful biomarker candidates to characterize patients with PDAC + DM. Data are available via ProteomeXchange with the identifier PXD053169.

Role and mechanism of specialized pro-resolving mediators in obesity-associated insulin resistance

With the changing times, obesity has become a characteristic epidemic in the context of the current era. Insulin resistance (IR) is most commonly caused by obesity, and IR is a common basis of the pathogenesis of many diseases such as cardiovascular disease, nonalcoholic fatty liver disease, and type 2 diabetes, which seriously threaten human life, as well as health. A major pathogenetic mechanism of obesity-associated IR has been found to be chronic low-grade inflammation in adipose tissue. Specialized pro-resolving mediators (SPMs) are novel lipid mediators that both function as "stop signals" for inflammatory reaction and promote inflammation to subside. In this article, we summarize the pathogenesis of obesity-associated IR and its treatments and outline the classification and biosynthesis of SPMs and their mechanisms and roles in the treatment of obesity-associated IR in order to explore the potential of SPMs for treating metabolic diseases linked with obesity-associated IR.

Unexplained Residual Risk In Type 2 Diabetes: How Big Is The Problem?

PURPOSE OF REVIEW

What is new? Cardiovascular disease (CVD) is the leading cause of mortality in type 2 diabetes (T2D) individuals. Of the major risk factors for CVD, less than 10% of T2D people meet the American Diabetes Association/American Heart Association recommended goals of therapy. The present review examines how much of the absolute cardiovascular (CV) risk in type 2 diabetes patients can be explained by major CV intervention trials.

RECENT FINDINGS

Multiple long-term cardiovascular (CV) intervention trials have examined the effect of specific target-directed therapies on the MACE endpoint. Only one prospective study, STENO-2, has employed a multifactorial intervention comparing intensified versus conventional treatment of modifiable risk factors in T2D patients, and demonstrated a 20% absolute CV risk reduction. If the absolute CV risk reduction in these trials is added to that in the only prospective multifactorial intervention trial (STENO-2), the unexplained CV risk is 44.1%. What are the clinical implications? Potential explanations for the unaccounted-for reduction in absolute CV risk in type 2 diabetes (T2D) patients are discussed.

HYPOTHESIS

failure to take into account synergistic interactions between major cardiovascular risk factors is responsible for the unexplained CV risk in T2D patients. Simultaneous treatment of all major CV risk factors to recommended AHA/ADA guideline goals is required to achieve the maximum reduction in CV risk.

Obesity: current state of the problem, multidisciplinary approach. (based on the consensus of the World Gastroenterological Organization “Obesity 2023” and the European guideline on obesity care in patients with gastrointestinal and liver diseases, 2022)

Obesity is the largest pandemic in the world, and its prevalence continues to increase. The purpose of the presented publication is to raise awareness of doctors about modern methods of diagnosing obesity and approaches to therapy, using an interdisciplinary team approach similar to that used in other chronic diseases, such as diabetes, heart disease and cancer. The article presents data from the World Gastroenterological Organization (2023) and the European Guidelines for the Treatment of Obesity in patients with diseases of the gastrointestinal tract and liver (2022). According to modern approaches, obesity should be considered as a chronic recurrent progressive disease, the treatment of which requires a comprehensive interdisciplinary approach involving psychologists and psychiatrists, nutritionists/nutritionists, therapists, endoscopists and surgeons, including lifestyle changes, a well-defined diet and exercise regimen, drug therapy, endoscopic or surgical methods of treatment. Conclusions. In order to stop the growing wave of obesity and its many complications and costs, doctors, insurance companies and health authorities should make systematic efforts to raise public awareness of both the adverse health risks associated with obesity and the potential reduction of risks through a comprehensive approach to therapy.

Insulin Resistance, Obesity, and Lipotoxicity

Lipotoxicity, originally used to describe the destructive effects of excess fat accumulation on glucose metabolism, causes functional impairments in several metabolic pathways, both in adipose tissue and peripheral organs, like liver, heart, pancreas, and muscle. Ectopic lipid accumulation in the kidneys, liver, and heart has important clinical counterparts like diabetic nephropathy in type 2 diabetes mellitus, obesity-related glomerulopathy, nonalcoholic fatty liver disease, and cardiomyopathy. Insulin resistance due to lipotoxicity indirectly lead to reproductive system disorders, like polycystic ovary syndrome. Lipotoxicity has roles in insulin resistance and pancreatic beta-cell dysfunction. Increased circulating levels of lipids and the metabolic alterations in fatty acid utilization and intracellular signaling have been related to insulin resistance in muscle and liver. Different pathways, like novel protein kinase c pathways and the JNK-1 pathway, are involved as the mechanisms of how lipotoxicity leads to insulin resistance in nonadipose tissue organs, such as liver and muscle. Mitochondrial dysfunction plays a role in the pathogenesis of insulin resistance. Endoplasmic reticulum stress, through mainly increased oxidative stress, also plays an important role in the etiology of insulin resistance, especially seen in non-alcoholic fatty liver disease. Visceral adiposity and insulin resistance both increase the cardiometabolic risk, and lipotoxicity seems to play a crucial role in the pathophysiology of these associations.

Effects of a high-fat meal on inflammatory and endothelial injury biomarkers in accordance with adiposity status: a cross-sectional study

Background

It is known that consuming a high-fat meal (HFM) induces microvascular dysfunction (MD) in eutrophic women and aggravates it in those with obesity. Our purpose was to investigate if the MD observed after a single HFM intake is caused by endothelial damage or increased inflammatory state, both determined by blood biomarkers.

Methods

Nineteen women with obesity (BMI 30-34.9 kg/m²) and 18 eutrophic ones (BMI 20.0-24.9 kg/m²) were enrolled into two groups: Obese (OBG) and Control (CG), respectively. Blood samples were collected at five-time points: before (fasting state) and 30, 60, 120, and 180 min after HFM intake to determine levels of adipokines (adiponectin, leptin), non-esterified fatty acid (NEFA), inflammatory [tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6)] and endothelium damage [soluble E-selectin, soluble vascular cell adhesion molecule-1 (sVCAM-1), soluble intercellular adhesion molecule-1 (sICAM-1), plasminogen activator inhibitor-1 (PAI-1)] biomarkers.

Results

Levels of soluble E-selectin, leptin, and PAI-1 were higher in OBG at all-time points (P < 0.05) compared to CG. In the fasting state, OBG had higher levels of NEFA compared to CG (P < 0.05). In intra-group analysis, no significant change in the levels of circulating inflammatory and endothelial injury biomarkers was observed after HFM intake, independently of the group.

Conclusion

Our findings suggest that women with obesity have an increased pro-inflammatory state and more significant endothelial injury compared to eutrophic ones. However, the consumption of a HFM was not sufficient to change circulating levels of inflammatory and endothelial injury biomarkers in either group.

Registration number for clinical trials:

NCT01692327.

Triglyceride-glucose index and non-culprit coronary plaque characteristics assessed by optical coherence tomography in patients following acute coronary syndrome: A cross-sectional study

Background

Triglyceride-glucose (TyG) index, a novel surrogate marker of insulin resistance, has been demonstrated to be significantly associated with cardiovascular disease. It remains indistinct regarding the association between TyG index and non-culprit coronary plaque characteristics in patients following acute coronary syndrome (ACS).

Methods

The present study retrospectively recruited patients who were diagnosed with ACS and underwent non-culprit optical coherence tomography (OCT) examination. The study population was divided into 2 groups based on the median of TyG index, which was calculated as Ln [fasting triglyceride (TG) (mg/dL) × fasting blood glucose (FBG) (mg/dL)/2]. The non-culprit plaque characteristics were determined by interpreting OCT images in accordance with the standard of previous consensus.

Results

110 patients (54.8 ± 12.1 years, 24.5% female) with 284 non-culprit plaques were included in the current analysis. TyG index was closely associated with high-risk plaque characteristics. Elevated TyG index was consistent to be an independent indicator for thin-cap fibroatheroma (TCFA) [odds ratio (OR) for per 1-unit increase 4.940, 95% confidence interval (CI) 1.652–14.767, P = 0.004; OR for taking lower median as reference 2.747, 95% CI 1.234–7.994, P = 0.011] and ruptured plaque (OR for per 1–unit increase 7.065, 95% CI 1.910–26.133, P = 0.003; OR for taking lower median as reference 4.407, 95% CI 1.208–16.047, P = 0.025) in fully adjusted model. The predictive value of TyG index for TCFA and ruptured plaque was moderate–to–high, with the area under the receiver operating characteristic curve (AUC) of 0.754 and 0.699 respectively. The addition of TyG index into a baseline model exhibited an incremental effect on the predictive value for TCFA, manifested as an increased AUC (0.681, 95% CI 0.570–0.793 vs. 0.782, 95% CI 0.688–0.877, P = 0.042), and significant continuous net reclassification improvement (0.346, 95% CI 0.235–0.458, P < 0.001) and integrated discrimination improvement (0.221, 95% CI 0.017–0.425, P = 0.034). TyG index failed to play an incremental effect on predicting ruptured plaque.

Conclusion

TyG index, which is simply calculated from fasting TG and FBG, can be served as an important and independent risk predictor for high-risk non-culprit coronary plaques in patients following ACS.

Insulin Resistance and High Blood Pressure: Mechanistic Insight on the Role of the Kidney

The metabolic effects of insulin predominate in skeletal muscle, fat, and liver where the hormone binds to its receptor, thereby priming a series of cell-specific and biochemically diverse intracellular mechanisms. In the presence of a good secretory reserve in the pancreatic islets, a decrease in insulin sensitivity in the metabolic target tissues leads to compensatory hyperinsulinemia. A large body of evidence obtained in clinical and experimental studies indicates that insulin resistance and the related hyperinsulinemia are causally involved in some forms of arterial hypertension. Much of this involvement can be ascribed to the impact of insulin on renal sodium transport, although additional mechanisms might be involved. Solid evidence indicates that insulin causes sodium and water retention, and both endogenous and exogenous hyperinsulinemia have been correlated to increased blood pressure. Although important information was gathered on the cellular mechanisms that are triggered by insulin in metabolic tissues and on their abnormalities, knowledge of the insulin-related mechanisms possibly involved in blood pressure regulation is limited. In this review, we summarize the current understanding of the cellular mechanisms that are involved in the pro-hypertensive actions of insulin, focusing on the contribution of insulin to the renal regulation of sodium balance and body fluids.

Can the Serum Endocan Level Be Used as a Biomarker to Predict Subclinical Atherosclerosis in Patients with Prediabetes?

BACKGROUND

Patients with prediabetes have an increased risk of atherosclerotic cardiovascular disease; therefore, early detection is important.

OBJECTIVE

The present study aimed to reveal the usability of serum endocan levels as a biomarker in the diagnosis of subclinical atherosclerosis in patients with prediabetes, based on CIMT measurements.

METHODS

Participants were classified according to the presence (n=42) or absence (n=42) of prediabetes. Serum endocan, fasting blood sugar, fasting insulin, and glycated hemoglobin (HbA1c) values of patients were examined, and CIMT was measured. The level of significance for statistical analysis was 0.05.

RESULTS

While serum endocan levels were found to be lower in patients with prediabetes, when compared to the control group (p=0.042), CIMT values were found to be higher (p=0.046). When evaluated by multivariate regression analysis, the serum endocan level was found to be associated with CIMT, regardless of other parameters (p=0.007). A negative correlation was found between plasma fasting insulin and endocan levels (r=-0.320, p=0.001).

CONCLUSIONS

Carotid intima media thickness was found to be high and the serum endocan level was low in patients with prediabetes. Decreased serum endocan levels in patients with prediabetes may be a contributing factor to atherosclerosis formation mechanisms.

Hypertension in Patients with Insulin Resistance: Etiopathogenesis and Management in Children

Insulin resistance (IR) is a key component in the etiopathogenesis of hypertension (HS) in patients with diabetes mellitus (DM). Several pathways have been found to be involved in this mechanism in recent literature. For the above-mentioned reasons, treatment of HS should be specifically addressed in patients affected by DM. Two relevant recently published guidelines have stressed this concept, giving specific advice in the treatment of HS in children belonging to this group: the European Society of HS guidelines for the management of high blood pressure in children and adolescents and the American Academy of Pediatrics Clinical Practice Guideline for Screening and Management of High Blood Pressure in Children and Adolescents. Our aim is to summarize the main pathophysiological mechanisms through which IR causes HS and to highlight the specific principles of treatment of HS for children with DM.

Association Between a Novel Metabolic Score for Insulin Resistance and Mortality in People With Diabetes

BACKGROUND

Growing studies have shown that insulin resistance (IR) is associated with poor prognoses among patients with diabetes, whereas the association between IR and mortality has not been determined. Hence we aimed to evaluate the associations between IR and all-cause, cardiovascular diseases (CVDs) and cancer-related mortality in patients with diabetes.

METHODS

We enrolled 2,542 participants with diabetes with an average age of 57.12 ± 0.39 years and 52.8% men from the 1999-2014 National Health and Nutrition Examination Survey (NHANES 1999-2014). A novel metabolic score for insulin resistance (METS-IR) was considered as alternative marker of IR. Mortality data were obtained from the National Death Index records and all participants were followed up until December 31, 2015. Cox proportional hazards regression, restricted cubic spline and Kaplan-Meier survival curves were performed to evaluate the associations between METS-IR and all-cause and cause-specific mortality in patients with diabetes.

RESULTS

During 17,750 person-years of follow-up [median (months), 95% CI: 90, 87-93], 562 deaths were documented, including 133 CVDs-related deaths and 90 cancer-related deaths. Multivariate Cox regression showed that compared with Quintile 1 (METS-IR ≤ 41), METS-IR in Quintile 2, 3, and 4 was all associated with all-cause mortality (Q2 vs. Q1: HR 0.65, 95% CI 0.49-0.87, P = 0.004; Q3 vs. Q1: HR 0.69, 95% CI 0.50-0.96, P = 0.029; Q4 vs. Q1: HR 0.57, 95% CI 0.36-0.91, P = 0.019; respectively). Restricted cubic spline indicated that METS-IR was non-linearly associated with all-cause and CVDs-related mortality. Threshold effect analyses determined that threshold values of METS-IR for all-cause and CVDs-related mortality were both 33.33. Only METS-IR below the threshold was negatively associated with all-cause and CVDs-related mortality (HR 0.785, 95% CI 0.724-0.850, P < 0.001; HR 0.722, 95% CI 0.654-0.797, P < 0.001; respectively). Sensitivity analyses showed that when excluding participants who died within 1 years of follow-up, the results of threshold effect analyses remained consistent, whereas excluding participants with CVDs, METS-IR below the threshold was only negatively correlated with all-cause mortality. Subgroup analyses indicated that for all-cause mortality, the results were still stable in all subgroups except newly diagnosed diabetes, but for CVDs-related mortality, the association persisted only in participants who were ≤ 65 years, male, White, non-White, already diagnosed diabetes, or uesd oral drugs, insulin, insulin sensitizing drugs.

CONCLUSION

METS-IR was non-linearly associated with all-cause and CVDs-related mortality in patients with diabetes, and METS-IR below the threshold was negatively associated with all-cause and CVDs-related mortality.

Coagulation and Endothelial Dysfunction Associated with NAFLD: Current Status and Therapeutic Implications

Non-alcoholic fatty liver disease (NAFLD) is closely related to insulin resistance, type 2 diabetes mellitus and obesity. It is considered a multisystem disease and there is a strong association with cardiovascular disease and arterial hypertension, which interfere with changes in the coagulation system. Coagulation disorders are common in patients with hepatic impairment and are dependent on the degree of liver damage. Through a review of the literature, we consider and discuss possible disorders in the coagulation cascade and fibrinolysis, endothelial dysfunction and platelet abnormalities in patients with NAFLD.

Percutaneous coronary intervention in insulin-treated diabetic patients: A meta-analysis

Background

This meta‐analysis of randomized controlled trials (RCTs) compared long‐term adverse clinical outcomes of percutaneous coronary intervention (PCI) in insulin‐treated diabetes mellitus (ITDM) and non‐ITDM patients.

Methods

This is a meta‐analysis study. The PubMed and Embase databases were searched for articles on long‐term adverse clinical outcomes of PCI in ITDM and non‐ITDM patients. The risk ratios (RR) and 95% confidence intervals (CI) were calculated.

Results

A total of 11 related RCTs involving 8853 DM patients were included. Compared with non‐ITDM patients, ITDM patients had significantly higher all‐cause mortality (ACM) (RR = 1.52, 95% CI: 1.25–1.85, p_{heterogeneity} = .689, I² = 0%), major adverse cardiac and cerebrovascular events (MACCE) (RR = 1.35, 95% CI: 1.18–1.55, p_{heterogeneity} = .57, I² = 0%), myocardial infarction (MI) (RR = 1.41, 95% CI: 1.16–1.72, p_{heterogeneity} = .962, I² = 0%), and stent thrombosis (ST) (RR = 1.75, 95% CI: 1.23–2.48, p_{heterogeneity} = .159, I² = 32.4%). No significant difference was found in the target lesion revascularization (TLR) and target vessel revascularization (TVR) between the ITDM and non‐ITDM groups.

Conclusions

The results showed that ITDM patients had significantly higher ACM, MACCE, MI, and ST, compared with non‐ITDM patients.

Associations between the triglyceride-glucose index and cardiovascular disease in over 150,000 cancer survivors: a population-based cohort study

Background

The prevention of subsequent cardiovascular disease (CVD) is an essential part of cancer survivorship care. We conducted the present study to investigate the association between the TyG index (a surrogate marker of insulin resistance) and the risk of cardiovascular disease (CVD) events in cancer survivors.

Methods

Adult cancer patients, who underwent routine health examinations during 2009–2010 and were survived for more than 5 years as of January 1, 2011, were followed for hospitalization of CVD (either ischemic heart disease, stroke, or heart failure) until December 2020. Cox model was used to calculate hazard ratios associated with baseline TyG index (log_e [fasting triglyceride (mg) × fasting glucose (mg)/2]) for the CVD hospitalization.

Results

A total of 155,167 cancer survivors (mean age 59.9 ± 12.0 years, female 59.1%) were included in this study. A graded positive association was observed between TyG and CVD hospitalization. An 8% elevated risk for CVD hospitalization was observed for a TyG index of 8-8.4 (aHR 1.08 [95% CI 1.01–1.14]); 10% elevated risk for a TyG index of 8.5–8.9 (aHR 1.10 [95% CI 1.03–1.17]); 23% elevated risk for a TyG index of 9.0-9.4 (aHR 1.23 [95% CI 1.15–1.31]); 34% elevated risk for a TyG index of 9.5–9.9 (aHR 1.34 [95% CI 1.23–1.47]); and 55% elevated risk for a TyG index ≥ 10 compared to the reference group (TyG index < 8). Per 1-unit increase in the TyG index, a 16% increase in CVD hospitalization and a 45% increase in acute myocardial infarction hospitalization were demonstrated. Graded positive associations were evident for atherosclerotic CVD subtypes, such as ischemic heart disease, acute myocardial infarction, and ischemic stroke, but not for hemorrhagic stroke or heart failure.

Conclusions

The TyG index may serve as a simple surrogate marker for the risk stratification of future CVD events, particularly atherosclerotic subtypes, in cancer survivors.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12933-022-01490-z.

Insulin: The master regulator of glucose metabolism

Insulin is the master regulator of glucose, lipid, and protein metabolism. Following ingestion of an oral glucose load or mixed meal, the plasma glucose concentration rises, insulin secretion by the beta cells is stimulated and the hyperinsulinemia, working in concert with hyperglycemia, causes: (i) suppression of endogenous (primarily reflects hepatic) glucose production, (ii) stimulation of glucose uptake by muscle, liver, and adipocytes, (iii) inhibition of lipolysis leading to a decline in plasma FFA concentration which contributes to the suppression of hepatic glucose production and augmentation of muscle glucose uptake, and (iv) vasodilation in muscle, which contributes to enhanced muscle glucose disposal. Herein, the integrated physiologic impact of insulin to maintain normal glucose homeostasis is reviewed and the molecular basis of insulin's diverse actions in muscle, liver, adipocytes, and vasculature are discussed.

Increasing prevalence of fasting hyperglycemia in adolescents aged 10-18 years and its relationship with metabolic indicators: the Korea National Health and Nutrition Examination Study (KNHANES), 2007-2018

PURPOSE

Pediatric diabetes is a common health burden worldwide. This study aimed to investigate the prevalence of fasting hyperglycemia in Korean youth aged 10-18 years and to evaluate its association with metabolic indicators.

METHODS

To assess the risk of diabetes in domestic children and adolescents, the prevalence of fasting hyperglycemia was calculated, a trend was evaluated using multi-year Korea National Health and Nutrition Examination Survey (KNHANES) data, and multivariate analysis was performed to evaluate the relationships between hyperglycemia and metabolic factors.

RESULTS

The prevalence of fasting hyperglycemia, defined as impaired fasting glucose (fasting glucose level > 100 mg/dL and < 125 mg/dL), or diabetes mellitus (fasting glucose ≥ 126 mg/dL) was estimated in Korean teenagers. The prevalence increased from the fourth (2007-2009) to the fifth (2010-2012), sixth (2013-2015), and seventh (2016-2018) KNHANES surveys, from 5.39 to 4.79, 10.03, and 11.66 per 100 persons, respectively. In multivariate analysis, systolic blood pressure and serum triglycerides were higher in the fasting hyperglycemia group; systolic blood pressures were 109.83 mmHg and 112.64 mmHg and serum triglycerides were 81.59 mg/dL and 89.60 mg/dL in the normal blood glucose and fasting hyperglycemia groups, respectively.

CONCLUSION

The prevalence of fasting hyperglycemia among children and adolescents has increased over the past decade, and this increase is potentially associated with metabolic abnormalities such as hypertension and hypertriglyceridemia. Effort is urgently required to reduce this chronic medical burden in adolescence.

Insulin Resistance Promotes the Formation of Aortic Dissection by Inducing the Phenotypic Switch of Vascular Smooth Muscle Cells

Background

Insulin resistance (IR) plays a key role in the development of type 2 diabetes mellitus (T2DM) and is one of its most important characteristics. Previous studies have shown that IR and T2DM were independent risk factors for a variety of cardiovascular and cerebrovascular diseases. However, there are few studies on the relationship between IR and aortic dissection (AD). The goal of this research was to find evidence that IR promotes the occurrence of AD.

Methods

Through the statistical analysis, we determined the proportion of glycosylated hemoglobin (HbA1c) abnormalities (HbA1c > 5.7) in people with acute thoracic aortic dissection (ATAD) and compared the difference of messenger RNA (mRNA) and protein expression of GluT1 in the thoracic aorta of normal people and those with ATAD to find evidence that IR is a causative factor in AD. The mouse model of IR and AD and the IR model of human aortic vascular smooth muscle cells (HA-VSMC) were established. Real time-PCR (RT-PCR) and Western blotting were used to study the mRNA and protein expression. Hematoxylin and eosin (H&E), Masson, and elastic fiber staining, and immunofluorescence were used to study the morphological structure.

Results

The proportion of HbA1c abnormalities in patients with ATAD was 59.37%, and the mRNA and protein expression of GluT1 were significantly lower than that in normal people. Fasting glucose concentration (FGC), serum insulin concentration (SIC), and the homeostasis model assessment of insulin resistance (HOMA-IR) of mice was obviously increased in the high-fat diet group and the protein expressions of Glut1 and GluT4 were reduced, indicating that the mouse IR model was successfully established. The incidence of AD was different between the two groups (IR: 13/14, Ctrl: 6/14), and the protein expression of MMP2, MMP9, and OPN were upregulated and SM22 and α-SMA were downregulated in mice. The expressions of mRNA and protein of GluT1 and SM22 in HA-VSMCs with IR were reduced and OPN was increased.

Conclusion

Combined results of clinical findings, mouse models, and cell experiments show that IR induced the phenotypic switching of vascular smooth muscle cells (VSMCs) from contractile to synthetic, which contributes to the occurrence of AD. It provides a basis for further research on the specific mechanism of how IR results in AD and a new approach for the prevention and treatment of AD.

Inhibition of dipeptidyl peptidase-4 averts free fatty acids deposition in the hearts of oral estrogen-progestin contraceptive-induced hyperinsulinemic female rats

Free fatty acid (FFA) deposition in non-adipose tissues such as the heart is a characteristic of insulin resistant states which feature hyperinsulinemia and dipeptidyl peptidase-4 (DPP-4) activation. Estrogen-progestin oral contraceptives (OC) treatment reportedly increased DPP-4 activity in rat tissue, and DPP-4 inhibitors have anti-diabetic and anti-inflammatory properties. This study aims to investigate the effects of DPP-4 inhibition on cardiac FFA deposition in estrogen-progestin-treated female rats. From our data, estrogen-progestin OC exposure in female rats led to elevated plasma insulin, cardiac DPP-4 activity, FFA and triglyceride (TG) accumulation, TG/high-density lipoprotein cholesterol (TG/HDL-C) ratio, adenosine deaminase/xanthine oxidase/uric acid pathway (ADA/XO/UA), lipid peroxidation, glycogen synthase activity, and alanine phosphatase; whereas cardiac glucose-6-phosphate dehydrogenase, Na+/K+-ATPase and nitric oxide (NO) were decreased. However, DPP-4 inhibition resulted in decreased plasma insulin, cardiac DPP-4 activity, FFA, TG, TG/HDL-C ratio, and alkaline phosphatase. These were accompanied by reduced ADA/XO/UA pathway, lipid peroxidation, and augmented NO and Na+/K+-ATPase in estrogen-progestin OC-treated rats. DPP-4 inhibition attenuated cardiac lipid deposition accompanied by reduced activity in the ADA/XO/UA pathway in estrogen-progestin OC-treated female rats. DPP-4 is therefore a plausible therapeutic target in cardiometabolic disorders.

Comparison of EQ-5D-3L and metabolic components between patients with hyperhidrosis and the general population: a propensity score matching analysis

PURPOSE

It is important to understand the characteristics of patients with hyperhidrosis, which are different from the general population, for treating hyperhidrosis. Sympathetic overactivity, which might play an important role in hyperhidrosis, can contribute to metabolic diseases and the decreased quality of life (QoL). We compared the metabolic components and health-related QoL between patients with hyperhidrosis and the general population.

METHODS

We conducted a case-control study and compared the characteristics of the patients (N = 196) with hyperhidrosis and propensity score-matched controls (N = 196) selected from the Korean National Health and Nutrition Examination Survey. Metabolic components and EQ-5D-3L (EQ-5D) index were compared using a two-way mixed analysis of covariance after adjusting for confounders.

RESULTS

Patients with hyperhidrosis had significantly higher waist circumference (estimated mean values ± SD for patients and the control group, 85.5  ±  10.8 cm vs 81.3  ±  10.3 cm, p < 0.001), blood pressure (SBP, 121.1  ±  16.9 vs 111.7  ±  10.3, p < 0.001 AND DBP, 77.5  ±  12.8 vs 73.6  ±  8.6, p < 0.001, respectively), fasting glucose (97.1  ±  11.3 vs 91.5  ±  9.2, p < 0.001), and the number of components of metabolic syndrome (1.4  ±  1.3 vs 1.0  ±  1.2, p = 0.002), and significantly lower estimated glomerular filtration rate (144.3  ±  53.2 vs 158.3  ±  55.7, p = 0.002) and EQ-5D values (estimated mean values (standard error) for patients and the control group, 0.92 (0.01) vs 0.97 (0.01), p < 0.001) compared to the control group after adjustment.

CONCLUSION

The patients with hyperhidrosis had more central obesity and unfavorable metabolic parameters and a lower EQ-5D index compared with the general population, emphasizing clinical importance of hyperhidrosis to be cured in aspect of metabolic components as well as patients' QOL.

Association study of fasting blood glucose and salt sensitivity of blood pressure in community population: The EpiSS study

BACKGROUND AND AIMS

To evaluate the association between fasting blood glucose (FBG) and salt sensitivity of blood pressure (SSBP).

METHODS AND RESULTS

This study is based on the baseline survey of systemic epidemiology of salt sensitivity study. Subjects were classified into salt sensitive (SS) and salt resistant groups according to blood pressure (BP) changes during the modified Sullivan's acute oral saline load and diuresis shrinkage test. Multivariate logistic and linear regression were used to evaluate associations between FBG with SS or BP changes. A total of 2051 participants were included in the analyses with 581 (28.33%) for SS. Multiple analysis showed that for every interquartile range increase in FBG, the OR (95%CI) for SS was 1.140 (1.069, 1.215), β (95%CI) for mean arterial pressure change (ΔMAP₁), systolic and diastolic BP changes during saline load were 0.421 (0.221, 0.622), 0.589 (0.263, 0.914) and 0.340 (0.149, 0.531), respectively. Compared to the lowest FBG quartile (Q₁), the OR (95%CI) for SS in Q₃ and Q₄ were 1.342 (1.014, 1.776) and 1.577 (1.194, 2.084), respectively. Compared to subjects with normal FBG, the β (95%CI) for ΔMAP₁ was 0.973 (0.055, 1.891) in subjects with impaired FBG, and was 1.449 (0.602, 2.296) in patients with diabetes mellitus. Stratified analyses showed significant and stronger associations between FBG with SSBP in youngers, females, hypertensives, non-diabetics, non-current smokers and non-current drinkers.

CONCLUSION

Our findings suggest FBG is an independent, dose-dependent associated factor for SSBP, and prevention of SS focusing on controlling FBG elevation in the early stage is important.

Effects of renal denervation on cardiovascular, metabolic and renal functions in streptozotocin-induced diabetic rats

Diabetes promotes renal sympathetic hyperactivity, autonomic imbalance, and cardiovascular and renal dysfunction. Bilateral renal denervation (BRD) has emerged as a treatment for diabetes; however, the mechanisms that underlie the beneficial effects of BRD are unknown.

AIMS

The present study evaluated the effects of BRD on autonomic, cardiovascular, metabolic, and renal function in streptozotocin-diabetic rats.

MAIN METHODS

Wistar rats were separated into three experimental groups: control (CTR), diabetic (DM), and diabetic that underwent BRD (DM BRD). BRD was performed two weeks after STZ-diabetes induction, the experiments were performed four weeks after DM induction. This study evaluated sympathetic vasomotor nerve activity in different territories (renal, lumbar and splanchnic), arterial baroreceptor reflex, metabolic and renal function.

KEY FINDINGS

BRD significantly reduced glycemia, glycosuria, albuminuria, and SGLT2 gene expression in the kidney in DM rats. Renal sympathetic nerve activity (rSNA) was significantly increased and splanchnic sympathetic nerve activity (sSNA) was significantly decreased in DM rats, without changes in lumbar sympathetic nerve activity (lSNA). BRD was able to normalize sSNA and significantly increase lSNA in DM rats compared to control rats. Additionally, cardiac baroreceptor sensitivity was impaired in DM rats, and BRD significantly improved baroreflex sensitivity.

SIGNIFICANCE

Our data suggest that renal nerves play an important role in autonomic, cardiovascular, and renal dysfunction in STZ-DM rats. Thus, sympathetic renal hyperactivity should be considered a possible therapeutic target in diabetic patients.

An association study between MiR-146a and INSR gene polymorphisms and hypertensive disorders of pregnancy in Northeastern Han Chinese population

INTRODUCTION

Hypertensive disorders of pregnancy(HDP) is a complex and challenging group of pregnancy complications that is one of the leading causes of maternal and fetal death worldwide. Recent studies have shown that the single nucleotide polymorphism(SNP) may play a role in the pathogenesis of HDP. This study aimed to investigate the association of MiR-146a rs2910164 and insulin receptor(INSR) rs2059806 SNPs with HDP and their associated complications in the Han population of Northeast China.

METHODS

A total of 240 HDP patients and 380 healthy controls were selected for genotype determination. For the most special and high incidence of HDP, we also studied the SNPs in association with pre-eclampsia(PE) patients. In addition, HDP complicated with gestational diabetes mellitus(GDM) patients was further analyzed to identify the association between SNPs and HDP-related complications. Multivariate logical regression analysis combined with 10, 000 permutation test corrections was used to analyze the association of MiR-146a and INSR SNPs with HDP.

RESULTS

After adjusting for relevant factors, MiR-146a rs2910164 or INSR rs2059806 SNPs were not significantly different between HDP or PE patients and healthy controls(P>0.05). Meanwhile, MiR146a rs2910164 and INSR rs2059806 SNPs were not significantly different between HDP complicated with GDM and control group.

DISCUSSION

Our data indicates that MiR-146a rs2910164 and INSR rs2059806 SNPs may not be significantly related with HDP in the Han population of Northeast China living in Heilongjiang Province.

Metabolic Syndrome Pathophysiology and Predisposing Factors

Metabolic syndrome (MetS) is a cluster of cardiometabolic risk factors with high prevalence among adult populations and elevated costs for public health systems worldwide. Despite the lack of consensus regarding the syndrome definition and diagnosis criteria, it is characterized by the coexistence of risk factors such as abdominal obesity, atherogenic dyslipidemia, elevated blood pressure, a prothrombotic and pro-inflammatory state, insulin resistance (IR), and higher glucose levels, factors indubitably linked to an increased risk of developing chronic conditions, such as type 2 diabetes (T2D) and cardiovascular disease (CVD). The syndrome has a complex and multifaceted origin not fully understood; however, it has been strongly suggested that sedentarism and unbalanced dietary patterns might play a fundamental role in its development. The purpose of this review is to provide an overview from the syndrome epidemiology, costs, and main etiological traits from its relationship with unhealthy diet patterns and sedentary lifestyles.

Morphological characteristics in diabetic cardiomyopathy associated with autophagy

Diabetic cardiomyopathy, clinically diagnosed as ventricular dysfunction in the absence of coronary atherosclerosis or hypertension in diabetic patients, is a cardiac muscle-specific disease that increases the risk of heart failure and mortality. Its clinical course is characterized initially by diastolic dysfunction, later by systolic dysfunction, and eventually by clinical heart failure from an uncertain mechanism. Light microscopic features such as interstitial fibrosis, inflammation, and cardiomyocyte hypertrophy are observed in diabetic cardiomyopathy, but are common to failing hearts generally and are not specific to diabetic cardiomyopathy. Electron microscopic studies of biopsy samples from diabetic patients with heart failure have revealed that the essential mechanism underlying diabetic cardiomyopathy involves thickening of the capillary basement membrane, accumulation of lipid droplets, and glycogen as well as increased numbers of autophagic vacuoles within cardiomyocytes. Autophagy is a conserved mechanism that contributes to maintaining intracellular homeostasis by degrading long-lived proteins and damaged organelles and is observed more often in cardiomyocytes within failing hearts. Diabetes mellitus (DM) impairs cardiac metabolism and leads to dysregulation of energy substrates that contribute to cardiac autophagy. However, a "snapshot" showing greater numbers of autophagic vacuoles within cardiomyocytes may indicate that autophagy is activated into phagophore formation or is suppressed due to impairment of the lysosomal degradation step. Recent in vivo studies have shed light on the underlying molecular mechanism governing autophagy and its essential meaning in the diabetic heart. Autophagic responses to diabetic cardiomyopathy differ between diabetic types: they are enhanced in type 1 DM, but are suppressed in type 2 DM. This difference provides important insight into the pathophysiology of diabetic cardiomyopathy. Here, we review recent advances in our understanding of the pathophysiology of diabetic cardiomyopathy, paying particular attention to autophagy in the heart, and discuss the therapeutic potential of interventions modulating autophagy in diabetic cardiomyopathy.

Analysis of the intricate effects of polyunsaturated fatty acids and polyphenols on inflammatory pathways in health and disease

Prevention and treatment of non-communicable diseases (NCDs), including cardiovascular disease, diabetes, obesity, cancer, Alzheimer's and Parkinson's disease, arthritis, non-alcoholic fatty liver disease and various infectious diseases; lately most notably COVID-19 have been in the front line of research worldwide. Although targeting different organs, these pathologies have common biochemical impairments - redox disparity and, prominently, dysregulation of the inflammatory pathways. Research data have shown that diet components like polyphenols, poly-unsaturated fatty acids (PUFAs), fibres as well as lifestyle (fasting, physical exercise) are important factors influencing signalling pathways with a significant potential to improve metabolic homeostasis and immune cells' functions. In the present manuscript we have reviewed scientific data from recent publications regarding the beneficial cellular and molecular effects induced by dietary plant products, mainly polyphenolic compounds and PUFAs, and summarize the clinical outcomes expected from these types of interventions, in a search for effective long-term approaches to improve the immune system response.

Chronic Inflammation in the Context of Everyday Life: Dietary Changes as Mitigating Factors

The lifestyle adopted by most people in Western societies has an important impact on the propensity to metabolic disorders (e.g., diabetes, cancer, cardiovascular disease, neurodegenerative diseases). This is often accompanied by chronic low-grade inflammation, driven by the activation of various molecular pathways such as STAT3 (signal transducer and activator of transcription 3), IKK (IκB kinase), MMP9 (matrix metallopeptidase 9), MAPK (mitogen-activated protein kinases), COX2 (cyclooxigenase 2), and NF-Kβ (nuclear factor kappa-light-chain-enhancer of activated B cells). Multiple intervention studies have demonstrated that lifestyle changes can lead to reduced inflammation and improved health. This can be linked to the concept of real-life risk simulation, since humans are continuously exposed to dietary factors in small doses and complex combinations (e.g., polyphenols, fibers, polyunsaturated fatty acids, etc.). Inflammation biomarkers improve in patients who consume a certain amount of fiber per day; some even losing weight. Fasting in combination with calorie restriction modulates molecular mechanisms such as m-TOR, FOXO, NRF2, AMPK, and sirtuins, ultimately leads to significantly reduced inflammatory marker levels, as well as improved metabolic markers. Moving toward healthier dietary habits at the individual level and in publicly-funded institutions, such as schools or hospitals, could help improving public health, reducing healthcare costs and improving community resilience to epidemics (such as COVID-19), which predominantly affects individuals with metabolic diseases.

Insulin Resistance the Link between T2DM and CVD: Basic Mechanisms and Clinical Implications

Insulin resistance (IR) is a cardinal feature of type 2 diabetes mellitus (T2DM). It also is associated with multiple metabolic abnormalities which are known cardiovascular disease (CVD) risk factors. Thus, IR not only contributes to the development of hyperglycemia in T2DM patients, but also to the elevated CVD risk. Improving insulin sensitivity is anticipated to both lower the plasma glucose concentration and decrease CVD risk in T2DM patients, independent of glucose control. We review the molecular mechanisms and metabolic consequences of IR in T2DM patients and discuss the importance of addressing IR in the management of T2DM.

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.

Circulating miRNAs as Biomarkers of Obesity and Obesity-Associated Comorbidities in Children and Adolescents: A Systematic Review

Early detection of obesity and its associated comorbidities in children needs priority for the development of effective therapeutic intervention. Circulating miRNAs (microRNAs) have been proposed as biomarkers for obesity and its comorbidities; therefore, we conducted a systematic review to summarize results of studies that have quantified the profile of miRNAs in children and adolescents with obesity and/or associated disorders. Nine studies aiming to examine differences in miRNA expression levels between children with normal weight and obesity or between obese children with or without cardiometabolic diseases were included in this review. We identified four miRNAs overexpressed in obesity (miR-222, miR-142-3, miR-140-5p, and miR-143) and two miRNAs (miR-122 and miR-34a) overexpressed in children with obesity and nonalcoholic fatty liver disease (NAFLD) and/or insulin resistance. In conclusion, circulating miRNAs are promising diagnostic biomarkers of obesity-associated diseases such as NAFLD and type 2 diabetes already in childhood. However, more studies in children, using massive search technology and with larger sample sizes, are required to draw any firm conclusions.

Impact of Insulin-Treated and Noninsulin-Treated Diabetes Mellitus in All-Comer Patients Undergoing Percutaneous Coronary Interventions With Polymer-Free Biolimus-Eluting Stent (from the RUDI-FREE Registry)

Patients with diabetes mellitus (DM) have worse outcomes after percutaneous coronary intervention (PCI). Recent evidences suggest a differential impact of insulin-treated and noninsulin-treated DM on prognosis. We evaluated the clinical outcome of diabetic patients after PCI with polymer-free biolimus-eluting stent from the RUDI-FREE Registry, investigating a possible different prognostic impact of insulin-treated and noninsulin-treated DM. A total of 1,104 consecutive patients who underwent PCI with polymer-free biolimus-eluting stent, enrolled in the RUDI-FREE observational, multicenter, single-arm registry, were stratified by diabetic status; diabetic population was further divided on the basis of insulin treatment. Primary end points of the study were target lesion failure (TLF; composite of cardiac death, target vessel myocardial infarction, target lesion revascularization) and major adverse cardiac and cerebrovascular events (composite of cardiac death, stroke, and myocardial infarction). Multiple ischemic adverse events were also single-handedly considered as secondary end points. At 1 year, TLF was significantly higher in the diabetic cohort, as compared with nondiabetic patients (6.0% vs 3.1%, p 0.022). None of the end points resulted significantly different between nondiabetics and noninsulin-treated diabetic patients. Divergently, compared with nondiabetic, insulin-treated diabetic patients faced significant higher rates of TLF (10.8% vs 3.1%, p 0.003), major adverse cardiac and cerebrovascular events (10.8% vs 3.4%, p 0.004), and of most of the analyzed adverse events. In conclusion, patients with DM had a higher risk of TLF compared with nondiabetics; nonetheless, the worse outcome of the diabetic population seems to be driven by the insulin-treated diabetic subpopulation. This finding suggests a different risk profile of insulin-treated and noninsulin-treated diabetic patients in the modern era of PCI.

Role and mechanism of cardiac insulin resistance in occurrence of heart failure caused by myocardial hypertrophy

Cardiac insulin resistance plays an important role in the development of heart failure, but the underlying mechanisms remain unclear. Here, we found that hypertrophic hearts exhibit normal cardiac glucose oxidation rates, but reduced fatty acid oxidation rates, compared to Sham controls under basal (no insulin) conditions. Furthermore, insulin stimulation attenuated insulin’s effects on cardiac substrate utilization, suggesting the development of cardiac insulin resistance. Consistent with insulin resistance, p38-MAPK protein levels were reduced in hypertrophic hearts. By contrast, systemic hyperinsulin-euglycemic clamp indicated normal insulin sensitivity. Finally, electron microscopy revealed severe mitochondrial damage in the hypertrophic myocardium. Our results indicate that that cardiac insulin resistance caused by cardiac hypertrophy is associated with mitochondrial damage and cardiac dysfunction. Moreover, our findings suggest that cardiac insulin resistance is independent of systemic insulin resistance, which is also a risk factor for heart failure.

Aminoguanidine reduces diabetes-associated cardiac fibrosis

Aminoguanidine (AG) inhibits advanced glycation end products (AGEs) and advanced oxidation protein products (AOPP) accumulated as a result of excessive oxidative stress in diabetes. However, the molecular mechanism by which AG reduces AGE-associated damage in diabetes is not well understood. Thus, we investigated whether AG supplementation mitigates oxidative-associated cardiac fibrosis in rats with type 2 diabetes mellitus (T2DM). Forty-five male Wistar rats were divided into three groups: Control, T2DM and T2DM+AG. Rats were fed with a high-fat, high-carbohydrate diet (HFCD) for 2 weeks and rendered diabetic using low-dose streptozotocin (STZ) (20 mg/kg), and one group was treated with AG (20 mg/kg) up to 25 weeks. In vitro experiments were performed in primary rat myofibroblasts to confirm the antioxidant and antifibrotic effects of AG and to determine if blocking the receptor for AGEs (RAGE) prevents the fibrogenic response in myofibroblasts. Diabetic rats exhibited an increase in cardiac fibrosis resulting from HFCD and STZ injections. By contrast, AG treatment significantly reduced cardiac fibrosis, α-smooth muscle actin (αSMA) and oxidative-associated Nox4 and Nos2 mRNA expression. In vitro challenge of myofibroblasts with AG under T2DM conditions reduced intra- and extracellular collagen type I expression and Pdgfb, Tgfβ1 and Col1a1 mRNAs, albeit with similar expression of Tnfα and Il6 mRNAs. This was accompanied by reduced phosphorylation of ERK1/2 and SMAD2/3 but not of AKT1/2/3 and STAT pathways. RAGE blockade further attenuated collagen type I expression in AG-treated myofibroblasts. Thus, AG reduces oxidative stress-associated cardiac fibrosis by reducing pERK1/2, pSMAD2/3 and collagen type I expression via AGE/RAGE signaling in T2DM.

Iron induces insulin resistance in cardiomyocytes via regulation of oxidative stress

Iron overload is associated with various pathological changes which contribute to heart failure. Here, we examined mechanisms via which iron alters cardiomyocyte insulin sensitivity. Treatment of primary adult and neonatal cardiomyocytes as well as H9c2 cells with iron decreased insulin sensitivity determined via Western blotting or immunofluorescent detection of Akt and p70S6K phosphorylation and glucose uptake. Using CellROX deep red or DCF-DA probes we also observed that iron increased generation of reactive oxygen species (ROS), and that pretreatment with the superoxide dismutase mimetic MnTBAP reduced ROS production and attenuated iron-induced insulin resistance. SKQ1 and allopurinol but not apocynin reduced iron-induced ROS suggesting mitochondria and xanthine oxidase contribute to cellular ROS in response to iron. Western blotting for LC3-I, LC3-II and P62 levels as well as immunofluorescent co-detection of autophagosomes with Cyto-ID and lysosomal cathepsin activity indicated that iron attenuated autophagic flux without altering total expression of Atg7 or beclin-1 and phosphorylation of mTORC1 and ULK1. This conclusion was reinforced via protein accumulation detected using Click-iT HPG labelling after iron treatment. The adiponectin receptor agonist AdipoRon increased autophagic flux and improved insulin sensitivity both alone and in the presence of iron. We created an autophagy-deficient cell model by overexpressing a dominant-negative Atg5 mutant in H9c2 cells and this confirmed that reduced autophagy flux correlated with less insulin sensitivity. In conclusion, our study showed that iron promoted a cascade of ROS production, reduced autophagy and insulin resistance in cardiomyocytes.

New approach to diabetes care: from blood glucose to cardiovascular disease

Diabetes, a metabolic disease with vascular consequences due to accelerated atherosclerosis, is one of the 21st century's most prevalent chronic diseases. Characterized by inability to produce or use insulin, leading to hyperglycemia and insulin deficiency, diabetes causes a variety of microvascular (such as retinopathy and kidney disease) and macrovascular complications (including myocardial infarction and stroke) which reduce the quality of life and life expectancy of individuals with diabetes. We describe the close relationship between diabetes, cardiovascular risk factors, and cardiovascular disease, and examine multifactorial approaches to diabetes treatment, including reducing cardiovascular risk in individuals with type 2 diabetes. Finally, we analyze new prospects for the treatment of type 2 diabetes, resulting from the development of novel antidiabetic drugs. The aim of this review is that the clinician should assume the crucial role of guiding individuals with diabetes in the control of their disease, in order to improve their quality of life and prognosis. In view of the currently available evidence, the emergence of new glucose-reducing therapies with proven cardiovascular benefit means that the best therapeutic strategy for diabetes must go beyond reducing hyperglycemia and aim to reduce cardiovascular risk.

Anxa2 gene silencing attenuates obesity-induced insulin resistance by suppressing the NF-κB signaling pathway

Insulin resistance (IR) continues to pose a major threat to public health due to its role in the pathogenesis of metabolic syndrome and its ever-increasing prevalence on a global scale. The aim of the current study was to investigate the efficacy of Anxa2 in obesity-induced IR through the mediation of the NF-κB signaling pathway. Microarray analysis was performed to screen differentially expressed genes associated with obesity. To verify whether Anxa2 was differentially expressed in IR triggered by obesity, IR mouse models were established in connection with a high-fat diet (HFD). In the mouse IR model, the role of differentially expressed Anxa2 in glycometabolism and IR was subsequently detected. To investigate the effect of Anxa2 on IR and its correlation with inflammation, a palmitic acid (PA)-induced IR cell model was established, with the relationship between Anxa2 and the NF-κB signaling pathway investigated accordingly. Anxa2 was determined to be highly expressed in IR. Silencing Anxa2 was shown to inhibit IR triggered by obesity. When Anxa2 was knocked down, elevated expression of phosphorylated insulin receptor substrate 1 (IRS1), IRS1 and peroxisome proliferator-activated receptor coactivator-1a, and glucose tolerance and insulin sensitivity along with 2-deoxy-d-glucose uptake was detected, whereas decreased expression of suppressor of cytokine signaling 3, IL-6, IL-1β, TNF-α, and p50 was observed. Taken together, the current study ultimately demonstrated that Anxa2 may be a novel drug strategy for IR disruption, indicating that Anxa2 gene silencing is capable of alleviating PA or HFD-induced IR and inflammation through its negative regulatory role in the process of p50 nuclear translocation of the NF-κB signaling pathway.

Association between insulin resistance and the development of cardiovascular disease

For many years, cardiovascular disease (CVD) has been the leading cause of death around the world. Often associated with CVD are comorbidities such as obesity, abnormal lipid profiles and insulin resistance. Insulin is a key hormone that functions as a regulator of cellular metabolism in many tissues in the human body. Insulin resistance is defined as a decrease in tissue response to insulin stimulation thus insulin resistance is characterized by defects in uptake and oxidation of glucose, a decrease in glycogen synthesis, and, to a lesser extent, the ability to suppress lipid oxidation. Literature widely suggests that free fatty acids are the predominant substrate used in the adult myocardium for ATP production, however, the cardiac metabolic network is highly flexible and can use other substrates, such as glucose, lactate or amino acids. During insulin resistance, several metabolic alterations induce the development of cardiovascular disease. For instance, insulin resistance can induce an imbalance in glucose metabolism that generates chronic hyperglycemia, which in turn triggers oxidative stress and causes an inflammatory response that leads to cell damage. Insulin resistance can also alter systemic lipid metabolism which then leads to the development of dyslipidemia and the well-known lipid triad: (1) high levels of plasma triglycerides, (2) low levels of high-density lipoprotein, and (3) the appearance of small dense low-density lipoproteins. This triad, along with endothelial dysfunction, which can also be induced by aberrant insulin signaling, contribute to atherosclerotic plaque formation. Regarding the systemic consequences associated with insulin resistance and the metabolic cardiac alterations, it can be concluded that insulin resistance in the myocardium generates damage by at least three different mechanisms: (1) signal transduction alteration, (2) impaired regulation of substrate metabolism, and (3) altered delivery of substrates to the myocardium. The aim of this review is to discuss the mechanisms associated with insulin resistance and the development of CVD. New therapies focused on decreasing insulin resistance may contribute to a decrease in both CVD and atherosclerotic plaque generation.

Insulin signaling as a potential natural killer cell checkpoint in fatty liver disease

Insulin resistance is a key risk factor in the progression of nonalcoholic fatty liver disease (NAFLD) and may lead to liver fibrosis. Natural killer (NK) cells are thought to exert an antifibrotic effect through their killing of activated hepatic stellate cells (HSCs). Here, we investigated how the interplay between NK cells and HSCs are modified by insulin resistance in NAFLD. Fresh peripheral blood NK cells (clusters of differentiation [CD]56^dim, CD16⁺) were collected from 22 healthy adults and 72 patients with NAFLD not currently taking any medications and without signs of metabolic syndrome. NK cells were assessed for insulin receptor expressions and cytotoxic activity when cultured in medium with HSCs. Fibrosis severities in patients with NAFLD were correlated linearly with elevated serum proinflammatory cytokine expression and insulin resistance severity. At the same time, fibrosis severities inversely correlated with insulin receptor expressions on NK cells as well as with their cytotoxic activities determined by CD107a by flow cytometry. NK cells from donors exhibiting severe fibrosis and insulin resistance exhibited significant mammalian target of rapamycin and extracellular signal‐regulated kinase depletion (through NK cell western blot quantitation), increased apoptosis, and failure to attenuate HSC activation in vitro. While exposure to insulin stimulated the cytotoxic activity of healthy NK cells, rapamycin prevented this effect and reduced NK insulin receptor expressions. Conclusion: Elevated insulin levels in F1 and F2 fibrosis enhances NK cell cytotoxic activity toward HSCs and prevents fibrosis progression by insulin receptors and downstream mammalian target of rapamycin and extracellular signal‐regulated kinase pathways. At more advanced stages of insulin resistance (F3 and F4 fibrosis), impaired NK cell activity rooted in low insulin receptor expression and or low serum insulin levels could further deteriorate fibrosis and may likely lead to cirrhosis development. (Hepatology Communications 2018;2:285‐298)

miRNA15a regulates insulin signal transduction in the retinal vasculature

We previously reported that tumor necrosis factor alpha (TNFα) could inhibit insulin signal transduction in retinal cells. We recently found that miR15a/16 also reduced TNFα in retinal endothelial cells (REC) and in vascular specific miR15a/16 knockout mice. Since in silico programs suggested that miR15a could directly bind the insulin receptor, we wanted to determine whether miR15a altered insulin signal transduction. We used a luciferase-based binding assay to determine whether miR15a directly bound the insulin receptor. We then used Western blotting, ELISA, and qPCR to investigate whether miR15a altered insulin signaling proteins in REC and in both miR15a/16 endothelial cell knockout and overexpressing mice. We also treated some REC with resveratrol to determine if resveratrol could increase miR15a expression, since resveratrol is protective to the diabetic retina. We found that miR15a directly bound the 3'UTR of the insulin receptor. Treatment with resveratrol increased miR15a expression in REC grown in high glucose. While total insulin receptor levels were not altered, insulin signal transduction was reduced in REC grown in high glucose and was restored with treatment with resveratrol. miR15a knockout mice had reduced insulin receptor phosphorylation and Akt2 levels, with increased insulin receptor substrate 1 (IRS-1) phosphorylation on serine 307, a site known to inhibit insulin signaling. In contrast, overexpression of miR15a increased insulin signal transduction. Taken together, these data suggest that miR15a binds the insulin receptor and indirectly regulates insulin receptor actions. It also offers an additional mechanism by which resveratrol is protective to the diabetic retina.