An integrated view of insulin resistance and endothelial dysfunction

Endothelial microRNAs in INOCA patients with diabetes mellitus

Ischemia with non-obstructive coronary artery (INOCA) is a common cause of hospital admissions, leading to negative outcomes and reduced quality of life. Central to its pathophysiology is endothelial dysfunction, which contributes to myocardial ischemia despite the absence of significant coronary artery blockage. Addressing endothelial dysfunction is essential in managing INOCA to alleviate symptoms and prevent cardiovascular events. Recent studies have identified diabetes mellitus (DM) as a significant factor exacerbating INOCA complications by promoting endothelial impairment and coronary microvascular dysfunction. MicroRNAs (miRNAs) have emerged as potential biomarkers and therapeutic targets in various biological processes, including endothelial dysfunction and cardiovascular diseases. However, research on miRNA biomarkers in INOCA patients is sparse. In this study, we examined a panel of circulating miRNAs involved in the regulation of endothelial function in INOCA patients with and without DM. We analyzed miRNA expression using RT-qPCR in a cohort of consecutive INOCA patients undergoing percutaneous coronary intervention. We detected a significant dysregulation of miR-363-5p and miR-92a-3p in INOCA patients with DM compared to those without DM, indicating their role as biomarkers for predicting and monitoring endothelial dysfunction in INOCA patients with DM.

Associations between the TyG index and the ɑ-Klotho protein in middle-aged and older population relevant to diabetes mellitus in NHANES 2007-2016

BACKGROUND

The anti-aging protein Klotho has diverse functions in antioxidative stress and energy metabolism through several pathways. While it has been reported that α-Klotho is downregulated in patients with insulin resistance (IR), the association between Klotho and IR is complex and controversial. The triglyceride-glucose (TyG) index has provided a practical method for assessing IR. With this in mind, our study aimed to investigate the relationship between the TyG index and soluble α-Klotho protein levels in US populations, both with and without diabetes mellitus.

METHODS

This cross-sectional study analyzed data from middle-aged and older participants in the National Health and Nutrition Examination Survey (NHANES) conducted between 2007 and 2016. The participants were divided into two groups based on their diabetes mellitus status: those with diabetes and those without diabetes. To evaluate the relationship between the TyG index and the concentration of the α-Klotho protein in each group, a series of survey-weighted multivariable linear regression models were employed. Furthermore, to examine the association between these two variables, multivariable-adjusted restricted cubic spline curves and subgroup analysis were generated.

RESULTS

The study involved 6,439 adults aged 40 years or older, with a mean age of 57.8 ± 10.9 years. Among them, 1577 (24.5%) had diabetes mellitus. A subgroup analysis indicated that the presence of diabetes significantly affected the relationship between the TyG index and the α-Klotho level. After considering all covariables, regression analysis of the participants without diabetes revealed that the α-Klotho concentration decreased by 32.35 pg/ml (95% CI: -50.07, -14.64) with each one unit increase in TyG (p < 0.001). The decline in α-Klotho levels with elevated TyG was more pronounced in the female population. In patients with diabetes mellitus, a non-linear association between the TyG index and α-Klotho was observed. There was no significant correlation observed between the two when TyG index were below 9.7. However, there was an increase in klotho levels of 106.44 pg/ml for each unit increase in TyG index above 9.7 (95% CI: 28.13, 184.74) (p = 0.008).

CONCLUSION

Our findings suggested that the presence of diabetes may influence the relationship between the TyG index and soluble α-Klotho. Furthermore, there seem to be sex differences in individuals without diabetes. Further studies are necessary to validate these findings.

Oxidant-induced disruption of vascular K+ channel function: implications for diabetic vasculopathy

Diabetes in humans a chronic metabolic disorder characterised by hyperglycaemia, it is associated with an increased risk of cardiovascular disease, disruptions to metabolism and vascular functions. It is also linked to oxidative stress and its complications. Its role in vascular dysfunctions is generally reported without detailed impact on the molecular mechanisms. Potassium ion channel (K+ channels) are key regulators of vascular tone, and as membrane proteins, are modifiable by oxidant stress associated with diabetes. This review manuscript examined the impact of oxidant stress on vascular K+ channel functions in diabetes, its implication in vascular complications and metabolic and cardiovascular diseases.

Tophi and carotid atherosclerosis in gout patients: Role of insulin resistance

BACKGROUND AND AIM

Gout and cardiovascular disease are closely related, but the mechanism linking them is still unknown. Gout may affect the insulin signaling pathway inducing insulin resistance (IR). The study aims to evaluate the association between tophi and carotid atherosclerosis, considering the potential role of IR.

METHODS AND RESULTS

A total of 595 patients with gout aged 18 to 80 were enrolled in this study. Carotid intima-media thickness, plaques and tophi were evaluated by B-mode ultrasonography. IR was assessed by the HOMA index (hepatic IR) and Gutt index (peripheral IR). Multivariable logistic regression and interaction analysis were used to examine the association between tophi and IR and its impact on carotid atherosclerosis. Among these participants, the average age was 55.4 (±12.54) years, and 94.6 % were male. Tophi were associated with increased odds of carotid atherosclerosis and burden after adjustment for confounders (P < 0.05). Tophi and IR synergically interacted for inducing carotid atherosclerosis. The interaction between peripheral IR with tophi was more pronounced than hepatic IR with tophi.

CONCLUSIONS

Tophi were independently associated with carotid atherosclerosis risk. IR mediated a significant amount of the effect of tophi on the development of carotid atherosclerosis. Peripheral IR probably plays a more important role than hepatic IR does.

Association of hepatokines with markers of endothelial dysfunction and vascular reactivity in obese adolescents

OBJECTIVES

Obesity-induced insulin resistance (IR) is known to influence hepatic cytokines (hepatokines), including fibroblast growth factor (FGF-21), fetuin-A, and chemerin. This study aimed to investigate the association between hepatokines and markers of endothelial dysfunction and vascular reactivity in obese adolescents.

METHODS

A total of 45 obese adolescents were categorized into three groups based on glucose tolerance: normal glucose tolerance (NGT), prediabetes (PD), and type 2 diabetes (T2D). We examined the relationships between FGF-21, fetuin-A, and chemerin with endothelial markers (plasminogen activator inhibitor-1 [PAI-1], intercellular adhesion molecule-1 [ICAM-1], and vascular cell adhesion marker-1 [VCAM-1]) and vascular surrogates (brachial artery reactivity testing [BART] and peak reactive hyperemia [PRH]).

RESULTS

Obese adolescents (age 16.2±1.2 years; 62 % female, 65 % Hispanic) with NGT (n=20), PD (n=14), and T2D (n=11) had significant differences between groups in BMI; waist-hip ratio (p=0.05), systolic BP (p=0.008), LDL-C (p=0.02), PAI-1 (p<0.001). FGF-21 pg/mL (mean±SD: NGT vs. PD vs. T2D 54±42; 266±286; 160±126 p=0.006) and fetuin-A ng/mL (266±80; 253±66; 313±50 p=0.018), were significantly different while chemerin ng/mL (26±5; 31±10; 28±2) did not significantly differ between the groups. Positive correlations were found between chemerin and both PAI-1 (r=0.6; p=0.05) and ICAM-1 (r=0.6; p=0.05), FGF-21 and PAI-1 (r=0.6; p<0.001), and fetuin-A with TNFα (r=-0.4; p=0.05). Negative correlations were found between chemerin and PRH (r= -0.5; p=0.017) and fetuin-A and PRH (r=-0.4; p=0.05).

CONCLUSIONS

In our cohort, IR predicted higher FGF-21 levels suggesting a linear relationship may exist between the two parameters. Hepatokines can augment alterations in the microvascular milieu in obese adolescents as demonstrated by their associations with the markers PAI-1, ICAM-1, and PRH.

Reducing the Risk of Pre-Eclampsia in Women with Polycystic Ovary Syndrome Using a Combination of Pregnancy Screening, Lifestyle, and Medical Management Strategies

Polycystic ovary syndrome (PCOS) is a multisystem disorder that presents with a variety of phenotypes involving metabolic, endocrine, reproductive, and psychological symptoms and signs. Women with PCOS are at increased risk of pregnancy complications including implantation failure, miscarriage, gestational diabetes, fetal growth restriction, preterm labor, and pre-eclampsia (PE). This may be attributed to the presence of specific susceptibility features associated with PCOS before and during pregnancy, such as chronic systemic inflammation, insulin resistance (IR), and hyperandrogenism, all of which have been associated with an increased risk of pregnancy complications. Many of the features of PCOS are reversible following lifestyle interventions such as diet and exercise, and pregnant women following a healthy lifestyle have been found to have a lower risk of complications, including PE. This narrative synthesis summarizes the evidence investigating the risk of PE and the role of nutritional factors in women with PCOS. The findings suggest that the beneficial aspects of lifestyle management of PCOS, as recommended in the evidence-based international guidelines, extend to improved pregnancy outcomes. Identifying high-risk women with PCOS will allow targeted interventions, early-pregnancy screening, and increased surveillance for PE. Women with PCOS should be included in risk assessment algorithms for PE.

Associations between physical activity and all-cause and cardiovascular mortality in adults with type 2 diabetes mellitus: A prospective cohort study from NHANES 2007-2018

AIMS

To investigate the dose-response association between physical activity and all-cause and cardiovascular mortality in adults with type 2 diabetes mellitus and the effects of replacing sedentary behavior with physical activity.

METHODS

4808 adults with type 2 diabetes mellitus were included in NHANES 2007-2018. Cox proportional hazards models were used to calculate hazard ratios and 95% confidence intervals. Isotemporal substitution analyses were further to determine the possible benefit of replacing sedentary time.

RESULTS

During a median follow-up of 6.58 years, 902 deaths occurred, including 290 deaths from cardiovascular disease. Compared with the inactive group, the low-active and high-active groups were associated with declined risks of all-cause mortality [HRs (95% CIs) 0.64 (0.50, 0.83); 0.60 (0.50, 0.73), respectively] and cardiovascular mortality [0.50 (0.29, 0.88); 0.54 (0.39, 0.76)), respectively]. Dose-response analysis showed a significant U-shaped curve between physical activity and all-cause and cardiovascular mortality. Replacing 30 min/day of sedentary time with physical activity was substantially linked to a reduced risk of 8-32% mortality.

CONCLUSION

A high level of PA of 40.52 and 31.66 MET-h/week was respectively related to the lowest risk of all-cause and cardiovascular mortality. Replacing sedentary time with physical activity could benefit the type 2 diabetes mellitus population.

Alzheimer's Disease: Models and Molecular Mechanisms Informing Disease and Treatments

Alzheimer's Disease (AD) is a complex neurodegenerative disease resulting in progressive loss of memory, language and motor abilities caused by cortical and hippocampal degeneration. This review captures the landscape of understanding of AD pathology, diagnostics, and current therapies. Two major mechanisms direct AD pathology: (1) accumulation of amyloid β (Aβ) plaque and (2) tau-derived neurofibrillary tangles (NFT). The most common variants in the Aβ pathway in APP, PSEN1, and PSEN2 are largely responsible for early-onset AD (EOAD), while MAPT, APOE, TREM2 and ABCA7 have a modifying effect on late-onset AD (LOAD). More recent studies implicate chaperone proteins and Aβ degrading proteins in AD. Several tests, such as cognitive function, brain imaging, and cerebral spinal fluid (CSF) and blood tests, are used for AD diagnosis. Additionally, several biomarkers seem to have a unique AD specific combination of expression and could potentially be used in improved, less invasive diagnostics. In addition to genetic perturbations, environmental influences, such as altered gut microbiome signatures, affect AD. Effective AD treatments have been challenging to develop. Currently, there are several FDA approved drugs (cholinesterase inhibitors, Aß-targeting antibodies and an NMDA antagonist) that could mitigate AD rate of decline and symptoms of distress.

Noncoding RNAs: Versatile regulators of endothelial dysfunction

Noncoding RNAs have recently emerged as versatile regulators of endothelial dysfunction in atherosclerosis, a chronic inflammatory disease characterized by the formation of plaques within the arterial walls. Through their ability to modulate gene expression, noncoding RNAs, including microRNAs, long noncoding RNAs, and circular RNAs, play crucial roles in various cellular processes involved in endothelial dysfunction (ECD), such as inflammation, pyroptosis, migration, proliferation, apoptosis, oxidative stress, and angiogenesis. This review provides an overview of the current understanding of the regulatory roles of noncoding RNAs in endothelial dysfunction during atherosclerosis. It highlights the specific noncoding RNAs that have been implicated in the pathogenesis of ECD, their target genes, and the mechanisms by which they contribute to ECD. Furthermore, we have reviewed the current therapeutics in atherosclerosis and explore their interaction with noncoding RNAs. Understanding the intricate regulatory network of noncoding RNAs in ECD may open up new opportunities for the development of novel therapeutic strategies to combat ECD.

Quantitative Perfusion Imaging with Total-Body PET

Recently, PET systems with a long axial field of view have become the current state of the art. Total-body PET scanners enable unique possibilities for scientific research and clinical diagnostics, but this new technology also raises numerous challenges. A key advantage of total-body imaging is that having all the organs in the field of view allows studying biologic interaction of all organs simultaneously. One of the new, promising imaging techniques is total-body quantitative perfusion imaging. Currently, 15O-labeled water provides a feasible option for quantitation of tissue perfusion at the total-body level. This review summarizes the status of the methodology and the analysis and provides examples of preliminary findings on applications of quantitative parametric perfusion images for research and clinical work. We also describe the opportunities and challenges arising from moving from single-organ studies to modeling of a multisystem approach with total-body PET, and we discuss future directions for total-body imaging.

Elevated triglyceride-glucose index predisposes to the initial episode of peritonitis in chronic peritoneal dialysis patients

OBJECTIVE

The serum triglyceride-glucose (TyG) index is a marker of inflammation. However, the relationship between TyG index and peritoneal dialysis-related peritonitis (PDRP) is unclear. This study aimed to investigate the potential relationship between the baseline TyG index and the initial episode of PDRP.

METHODS

A total of 208 peritoneal dialysis (PD) patients were enrolled from January 1, 2012, to December 31, 2019 and followed up until December 31, 2022. They were divided into 2 groups according to the median TyG. The primary outcome was the occurrence of the initial episode of PDRP while on PD therapy. Kaplan-Meier curves and Cox regression analyses were used to examine the association between them.

RESULTS

Eighty-five initial episodes of PDRP were identified. The risk of PDRP was higher in the high-TyG index group (p = 0.030). Multivariate Cox regression analysis showed a higher risk of PDRP in patients with a high TyG index (HR = 1.800, 95% CI 1.511-2.815, p = 0.010).

CONCLUSION

The baseline serum TyG index was an independent risk factor for the initial episode of PDRP in chronic PD patients.

Association between visceral obesity and 10-year risk of first atherosclerotic cardiovascular diseases events among American adults: National Health and Nutrition Examination Survey

Background

In the United States, the relationship between visceral obesity and the risk of developing atherosclerosis cardiovascular disease (ASCVD) for the first time in 10 years is unclear.

Methods

Data for this cross-sectional study came from the National Health and Nutrition Examination Survey (NHANES) from 2011 to 2020. We collected variable information related to 10-year ASCVD risk and visceral obesity reliable indicators [Visceral obesity index (VAI) and Lipid accumulation product (LAP)]. And we used multiple logistic regression to analyze the correlation of visceral obesity indicators (VAI and LAP) with 10-year ASCVD risk. In addition, we assessed the linear relationship between VAI or LAP and 10-year ASCVD risk by smoothing curve fitting. Finally, we conducted subgroup analysis and sensitivity analysis after excluding participants with extreme VAI and LAP values to ensure that we obtained accurate and reliable results.

Results

Our study included a total of 1,547 participants (mean age: 56.5 ± 10.1, 60% of males). The results of the multiple logistic regression showed that compared with participants with the lowest VAI in the 1st Quartile (≤0.79), the adjusted OR values for VAI and elevated 10-year ASCVD risk in Q3 (1.30-2.14), and Q4 (≥2.15) were 2.58 (95% CI: 1.24-5.36, P = 0.011), 15.14 (95% CI: 6.93-33.05, P < 0.001), respectively. Compared with participants with the lowest LAP in the 1st Quartile (≤28.29), the adjusted OR values for VAI and elevated 10-year ASCVD risk in Q3 (46.52-77.00), and Q4 (≥77.01) were 4.63 (95% CI: 2.18-9.82, P < 0.001), 16.94 (95% CI: 6.74-42.57, P < 0.001), respectively. Stratified analysis showed that the association between VAI or LAP and the first ASCVD event was more pronounced in males.

Conclusion

Higher VAI or LAP scores are significantly associated with elevated 10-year ASCVD risk in adults aged 40 to 79 in the USA, which suggested that monitoring visceral obesity is crucial to reduce the risk of a first ASCVD event.

Cardiometabolic Risk, Peripheral Arterial Disease and Cardiovascular Events in Polycystic Ovary Syndrome: Time to Implement Systematic Screening and Update the Management

Polycystic ovary syndrome (PCOS) is a highly prevalent endocrine disorder in women of reproductive age. It presents with gynaecologic, metabolic, and psychologic manifestations. The dominant drivers of pathophysiology are hyperandrogenism and insulin resistance. Both conditions are related to cardiometabolic risk factors, such as obesity, hypertension, dyslipidaemia, hyperglycaemia, type 2 and gestational diabetes, nonalcoholic fatty liver disease and obstructive sleep apnoea. Women with PCOS of reproductive age consistently demonstrated an elevated risk of subclinical atherosclerosis, as indicated by different measurement methods, while findings for menopausal age groups exhibited mixed results. Translation of subclinical atherosclerosis into the increased incidence of peripheral arterial disease and major cardiovascular (CV) events is less clear. Although several expert groups have advised screening, the CV risk assessment and prevention of CV events are frequently underdiagnosed and overlooked aspects of the management of PCOS. A combination of lifestyle management and pharmacotherapy, including the promising new era of anti-obesity medicine, can lead to improvements in cardiometabolic health.

Leisure-time physical activity and mortality risk in type 2 diabetes: A nationwide cohort study

AIM

Physical activity improves insulin resistance, inhibits inflammation, and decreases the incidence of cardiovascular disease. These are major causes of death in patients with diabetes.

METHODS

The Taiwan National Health Interview Survey collected baseline characteristics of socioeconomic level, education, marriage, and health behaviour, including leisure time physical activity in 2001, 2005, 2009, and 2013. The National Health Insurance research dataset 2000-2016 contained detailed information on medical conditions, including all comorbidities. All-cause and cardiovascular deaths were confirmed by the National Death Registry.

RESULTS

A total of 4859 adults with type 2 diabetes were included in the analysis; 2389 (49 %) were men and the mean±SD age was 60±13 years. Kaplan-Meier curve of all-cause (log-rank P<0.001) and cardiovascular death (log-rank P=0.038) categorized by leisure-time physical activity showed a significant difference. The multivariable Cox regression model showed that those who had more leisure time physical activity had a significantly lower risk of all-cause death than those with no physical activity (physical activity of 1-800 MET-min/week HR = 0.66, 95% CI: 0.54-0.81, physical activity of >800 MET-min/week HR = 0.67, 95% CI: 0.56-0.81). A significant trend was also observed (P <0.001). Similar results were also observed for cardiovascular mortality (physical activity of 1-800 MET-min/week HR = 0.54, 95% CI: 0.36-0.84, physical activity of >800 MET-min/week HR = 0.78, 95% CI: 0.55-1.13).

CONCLUSION

For those with diabetes, increased leisure-time physical activity significantly reduced risk of all-cause and cardiovascular death. Further research is warranted to determine the proper prescription for physical activity to prolong healthy life.

Coronary Microvascular Dysfunction in Diabetes Mellitus: Pathogenetic Mechanisms and Potential Therapeutic Options

Diabetic patients are frequently affected by coronary microvascular dysfunction (CMD), a condition consisting of a combination of altered vasomotion and long-term structural change to coronary arterioles leading to impaired regulation of blood flow in response to changing cardiomyocyte oxygen requirements. The pathogenesis of this microvascular complication is complex and not completely known, involving several alterations among which hyperglycemia and insulin resistance play particularly central roles leading to oxidative stress, inflammatory activation and altered barrier function of endothelium. CMD significantly contributes to cardiac events such as angina or infarction without obstructive coronary artery disease, as well as heart failure, especially the phenotype associated with preserved ejection fraction, which greatly impact cardiovascular (CV) prognosis. To date, no treatments specifically target this vascular damage, but recent experimental studies and some clinical investigations have produced data in favor of potential beneficial effects on coronary micro vessels caused by two classes of glucose-lowering drugs: glucagon-like peptide 1 (GLP-1)-based therapy and inhibitors of sodium-glucose cotransporter-2 (SGLT2). The purpose of this review is to describe pathophysiological mechanisms, clinical manifestations of CMD with particular reference to diabetes, and to summarize the protective effects of antidiabetic drugs on the myocardial microvascular compartment.

Insulin Resistance and Type 2 Diabetes Mellitus: An Ultimatum to Renal Physiology

Insulin resistance (IR) is stated as diminished insulin action regardless of hyperinsulinemia. The usual target organs for insulin activities are the liver, skeletal muscle, and adipose tissue. Hence, the vasculature and kidneys are nonconventional target organs as the impacts of insulin on these are comparatively separate from other conventional target organs. Vasodilation is achieved by raising endothelial nitric oxide (NO) generation by initiating the phosphoinositide 3-kinase (PI3K) pathway. In insulin-nonresponsive conditions, this process is defective, and there is increased production of endothelin-1 through the mitogen-activated protein kinase/extracellular signal-regulated kinase (MAPK/ERK) pathway, which predominates the NO effects, causing vasoconstriction. Renal tubular cells and podocytes have insulin receptors, and their purposeful importance has been studied, which discloses critical acts of insulin signaling in podocyte survivability and tubular action. Diabetic nephropathy (DN) is a prevalent problem in individuals with hypertension, poor glycemic management, hereditary susceptibility, or glomerular hyperfiltration. DN could be a significant contributing factor to end-stage renal disease (ESRD) that results from chronic kidney disease (CKD). IR and diabetes mellitus (DM) are the constituents of syndrome X and are accompanied by CKD progression. IR performs a key part in syndrome X leading to CKD. However, it is indistinct whether IR individually participates in enhancing the threat to CKD advancement rather than CKD complexity. CKD is an extensive public health problem affecting millions of individuals worldwide. The tremendous spread of kidney disease intensifies people’s health impacts related to communicable and noncommunicable diseases. Chronic disease regulator policies do not include CKD at global, local, and/or general levels. Improved knowledge of the character of CKD-associated problems might aid in reforming diagnosis, prevention, and management.

A new signal that shrinks fat

Healthy white adipose tissue is dependent on proliferation of endothelial cells to maintain homeostasis or undergo expansion. A new study shows that endothelial cells communicate with adipocytes via polyamines to promote vascularization of adipose tissue, thereby reversing the metabolic effects of obesity.

Elevated TyG Index Predicts Incidence of Contrast-Induced Nephropathy: A Retrospective Cohort Study in NSTE-ACS Patients Implanted With DESs

BACKGROUND

Triglyceride-glucose (TyG) index is a reliable and specific biomarker for insulin resistance and is associated with renal dysfunction. The present study sought to explore the relationship between TyG index and the incidence of contrast-induced nephropathy (CIN) in non-ST elevation acute coronary syndrome (NSTE-ACS) patients implanted with drug-eluting stents (DESs).

METHODS

A total of 1108 participants were recruited to the study and assigned to two groups based on occurrence of CIN. TyG index was calculated as ln [fasting triglycerides (mg/dL) × fasting blood glucose (mg/dL)/2]. Baseline characteristics and incidence of CIN were compared between the two groups. Logistic regression analysis was performed to evaluate the relationship between TyG index and CIN.

RESULTS

The results showed that 167 participants (15.1%) developed CIN. Subjects in the CIN group had a significantly higher TyG index compared with subjects in the non-CIN group (8.9 ± 0.7 vs. 9.3 ± 0.7, P<0.001). TyG index was significantly correlated with increased risk of CIN after adjusting for confounding factors irrespective of diabetes mellitus status and exhibited a J-shaped non-linear association. Subgroup analysis showed a significant gender difference in the relationship between TyG index and CIN. Receiver operating characteristic (ROC) curve analysis indicated that the risk assessment performance of TyG index was superior compared with other single metabolic indexes. Addition of TyG index to the baseline model increased the area under the curve from 0.713 (0.672-0.754) to 0.742 (0.702-0.782) and caused a reclassification improvement of 0.120 (0.092-0.149).

CONCLUSION

The findings from the present study show that a high TyG index is significantly and independently associated with incidence of CIN in NSTE-ACS patients firstly implanted with DESs. Routine preoperative assessment of TyG index can alleviate CIN and TyG index provides a potential target for intervention in prevention of CIN.

Dysfunctional Vascular Endothelium as a Driver of Atherosclerosis: Emerging Insights Into Pathogenesis and Treatment

Atherosclerosis, the chronic accumulation of cholesterol-rich plaque within arteries, is associated with a broad spectrum of cardiovascular diseases including myocardial infarction, aortic aneurysm, peripheral vascular disease, and stroke. Atherosclerotic cardiovascular disease remains a leading cause of mortality in high-income countries and recent years have witnessed a notable increase in prevalence within low- and middle-income regions of the world. Considering this prominent and evolving global burden, there is a need to identify the cellular mechanisms that underlie the pathogenesis of atherosclerosis to discover novel therapeutic targets for preventing or mitigating its clinical sequelae. Despite decades of research, we still do not fully understand the complex cell-cell interactions that drive atherosclerosis, but new investigative approaches are rapidly shedding light on these essential mechanisms. The vascular endothelium resides at the interface of systemic circulation and the underlying vessel wall and plays an essential role in governing pathophysiological processes during atherogenesis. In this review, we present emerging evidence that implicates the activated endothelium as a driver of atherosclerosis by directing site-specificity of plaque formation and by promoting plaque development through intracellular processes, which regulate endothelial cell proliferation and turnover, metabolism, permeability, and plasticity. Moreover, we highlight novel mechanisms of intercellular communication by which endothelial cells modulate the activity of key vascular cell populations involved in atherogenesis, and discuss how endothelial cells contribute to resolution biology - a process that is dysregulated in advanced plaques. Finally, we describe important future directions for preclinical atherosclerosis research, including epigenetic and targeted therapies, to limit the progression of atherosclerosis in at-risk or affected patients.

Resistance training increases insulin-induced vasodilation in the mesenteric artery of healthy rats

This study evaluated the ability of resistance training (RT) of moderate intensity to promote vascular changes in insulin-induced vasodilation in healthy animals. Wistar rats were divided into two groups: control (CON) and trained (eight weeks of training, performing 3 sets with 10 repetitions at 60% of maximum intensity). Forty-eight hours after the last session of the RT, the animals were sacrificed and vascular reactivity to insulin in the absence and presence of LY294002 (phosphatidylinositol 3-kinase inhibitors (PI3K), L-NAME (nitric oxide synthase (NOS) inhibitors) and BQ123 (endothelin A antagonist (ET-A) receptor). In addition, phenylephrine (Phe)-induced vasoconstriction in the absence and presence of L-NAME was also evaluated. The RT group showed greater vasodilation in maximal response compared to the CON group. After PI3K inhibition, vasodilation was reduced in both groups. However, when the NOS participation was evaluated, the RT group showed contraction in relation to the CON group, which was abolished by BQ123. In addition, the RT group had an increase in nitrite levels compared to the CON group. When the Phe response was evaluated, there was a reduction in tension in the RT group compared to the CON group. The results suggest that RT improves vascular reactivity.

Differential and Synergistic Effects of Low Birth Weight and Western Diet on Skeletal Muscle Vasculature, Mitochondrial Lipid Metabolism and Insulin Signaling in Male Guinea Pigs

Low birth weight (LBW) offspring are at increased risk for developing insulin resistance, a key precursor in metabolic syndrome and type 2 diabetes mellitus. Altered skeletal muscle vasculature, extracellular matrix, amino acid and mitochondrial lipid metabolism, and insulin signaling are implicated in this pathogenesis. Using uteroplacental insufficiency (UPI) to induce intrauterine growth restriction (IUGR) and LBW in the guinea pig, we investigated the relationship between UPI-induced IUGR/LBW and later life skeletal muscle arteriole density, fibrosis, amino acid and mitochondrial lipid metabolism, markers of insulin signaling and glucose uptake, and how a postnatal high-fat, high-sugar “Western” diet (WD) modulates these changes. Muscle of 145-day-old male LBW glucose-tolerant offspring displayed diminished vessel density and altered acylcarnitine levels. Disrupted muscle insulin signaling despite maintained whole-body glucose homeostasis also occurred in both LBW and WD-fed male “lean” offspring. Additionally, postnatal WD unmasked LBW-induced impairment of mitochondrial lipid metabolism, as reflected by increased acylcarnitine accumulation. This study provides evidence that early markers of skeletal muscle metabolic dysfunction appear to be influenced by the in utero environment and interact with a high-fat/high-sugar postnatal environment to exacerbate altered mitochondrial lipid metabolism, promoting mitochondrial overload.

Metformin in cardiovascular diabetology: a focused review of its impact on endothelial function

As a first-line treatment for diabetes, the insulin-sensitizing biguanide, metformin, regulates glucose levels and positively affects cardiovascular function in patients with diabetes and cardiovascular complications. Endothelial dysfunction (ED) represents the primary pathological change of multiple vascular diseases, because it causes decreased arterial plasticity, increased vascular resistance, reduced tissue perfusion and atherosclerosis. Caused by “biochemical injury”, ED is also an independent predictor of cardiovascular events. Accumulating evidence shows that metformin improves ED through liver kinase B1 (LKB1)/5'-adenosine monophosphat-activated protein kinase (AMPK) and AMPK-independent targets, including nuclear factor-kappa B (NF-κB), phosphatidylinositol 3 kinase-protein kinase B (PI3K-Akt), endothelial nitric oxide synthase (eNOS), sirtuin 1 (SIRT1), forkhead box O1 (FOXO1), krüppel-like factor 4 (KLF4) and krüppel-like factor 2 (KLF2). Evaluating the effects of metformin on endothelial cell functions would facilitate our understanding of the therapeutic potential of metformin in cardiovascular diabetology (including diabetes and its cardiovascular complications). This article reviews the physiological and pathological functions of endothelial cells and the intact endothelium, reviews the latest research of metformin in the treatment of diabetes and related cardiovascular complications, and focuses on the mechanism of action of metformin in regulating endothelial cell functions.

How Perturbated Metabolites in Diabetes Mellitus Affect the Pathogenesis of Hypertension?

The presence of hypertension (HTN) in type 2 diabetes mellitus (DM) is a common phenomenon in more than half of the diabetic patients. Since HTN constitutes a predictor of vascular complications and cardiovascular disease in type 2 DM patients, it is of significance to understand the molecular and cellular mechanisms of type 2 DM binding to HTN. This review attempts to understand the mechanism via the perspective of the metabolites. It reviewed the metabolic perturbations, the biological function of perturbated metabolites in two diseases, and the mechanism underlying metabolic perturbation that contributed to the connection of type 2 DM and HTN. DM-associated metabolic perturbations may be involved in the pathogenesis of HTN potentially in insulin, angiotensin II, sympathetic nervous system, and the energy reprogramming to address how perturbated metabolites in type 2 DM affect the pathogenesis of HTN. The recent integration of the metabolism field with microbiology and immunology may provide a wider perspective. Metabolism affects immune function and supports immune cell differentiation by the switch of energy. The diverse metabolites produced by bacteria modified the biological process in the inflammatory response of chronic metabolic diseases either. The rapidly evolving metabolomics has enabled to have a better understanding of the process of diseases, which is an important tool for providing some insight into the investigation of diseases mechanism. Metabolites served as direct modulators of biological processes were believed to assess the pathological mechanisms involved in diseases.

Hyperuricemia-induced endothelial insulin resistance: the nitric oxide connection

Hyperuricemia, defined as elevated serum concentrations of uric acid (UA) above 416 µmol L^-1, is related to the development of cardiometabolic disorders, probably via induction of endothelial dysfunction. Hyperuricemia causes endothelial dysfunction via induction of cell apoptosis, oxidative stress, and inflammation; however, it's interfering with insulin signaling and decreased endothelial nitric oxide (NO) availability, resulting in the development of endothelial insulin resistance, which seems to be a major underlying mechanism for hyperuricemia-induced endothelial dysfunction. Here, we elaborate on how hyperuricemia induces endothelial insulin resistance through the disruption of insulin-stimulated endothelial NO synthesis. High UA concentrations decrease insulin-induced NO synthesis within the endothelial cells by interfering with insulin signaling at either the receptor or post-receptor levels (i.e., proximal and distal steps). At the proximal post-receptor level, UA impairs the function of the insulin receptor substrate (IRS) and phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt) in the insulin signaling pathway. At the distal level, high UA concentrations impair endothelial NO synthase (eNOS)-NO system by decreasing eNOS expression and activity as well as by direct inactivation of NO. Clinically, UA-induced endothelial insulin resistance is translated into impaired endothelial function, impaired NO-dependent vasodilation, and the development of systemic insulin resistance. UA-lowering drugs may improve endothelial function in subjects with hyperuricemia.

Protein tyrosine phosphatase 1B inhibition improves endoplasmic reticulum stress‑impaired endothelial cell angiogenic response: A critical role for cell survival

Endoplasmic reticulum (ER) stress contributes to endothelial dysfunction, which is the initial step in atherogenesis. Blockade of protein tyrosine phosphatase (PTP)1B, a negative regulator of insulin receptors that is critically located on the surface of ER membrane, has been found to improve endothelial dysfunction. However, the role of ER stress and its related apoptotic sub‑pathways in PTP1B‑mediated endothelial dysfunction, particularly its angiogenic capacity, have not yet been fully elucidated. Thus, the present study aimed to investigate the impact of PTP1B suppression on ER stress‑mediated impaired angiogenesis and examined the contribution of apoptotic signals in this process. Endothelial cells were exposed to pharmacological ER stressors, including thapsigargin (TG) or 1,4‑dithiothreitol (DTT), in the presence or absence of a PTP1B inhibitor or small interfering (si)RNA duplexes. Then, ER stress, angiogenic capacity, cell cycle, apoptosis and the activation of key apoptotic signals were assessed. It was identified that the inhibition of PTP1B prevented ER stress caused by DTT and TG. Moreover, ER stress induction impaired the activation of endothelial nitric oxide synthase (eNOS) and the angiogenic capacity of endothelial cells, while PTP1B inhibition exerted a protective effect. The results demonstrated that blockade or knockdown of PTP1B prevented ER stress‑induced apoptosis and cell cycle arrest. This effect was associated with reduced expression levels of caspase‑12 and poly (ADP‑Ribose) polymerase 1. PTP1B blockade also suppressed autophagy activated by TG. The current data support the critical role of PTP1B in ER stress‑mediated endothelial dysfunction, characterized by reduced angiogenic capacity, with an underlying mechanism involving reduced eNOS activation and cell survival. These findings provide evidence of the therapeutic potential of targeting PTP1B in cardiovascular ischemic conditions.

Considerations for Maximizing the Exercise "Drug" to Combat Insulin Resistance: Role of Nutrition, Sleep, and Alcohol

Insulin resistance is a key etiological factor in promoting not only type 2 diabetes mellitus but also cardiovascular disease (CVD). Exercise is a first-line therapy for combating chronic disease by improving insulin action through, in part, reducing hepatic glucose production and lipolysis as well as increasing skeletal muscle glucose uptake and vasodilation. Just like a pharmaceutical agent, exercise can be viewed as a "drug" such that identifying an optimal prescription requires a determination of mode, intensity, and timing as well as consideration of how much exercise is done relative to sitting for prolonged periods (e.g., desk job at work). Furthermore, proximal nutrition (nutrient timing, carbohydrate intake, etc.), sleep (or lack thereof), as well as alcohol consumption are likely important considerations for enhancing adaptations to exercise. Thus, identifying the maximal exercise "drug" for reducing insulin resistance will require a multi-health behavior approach to optimize type 2 diabetes and CVD care.

Vascular dysfunction as a potential culprit of sarcopenia

Aging-related changes to biological structures such as cardiovascular and musculoskeletal systems contribute to the development of comorbid conditions including cardiovascular disease and frailty, and ultimately lead to premature death. Although, frail older adults often demonstrate both cardiovascular and musculoskeletal comorbidities, the etiology of sarcopenia, and especially the contribution of cardiovascular aging is unclear. Aging-related vascular calcification is prevalent in older adults and is a known risk factor for cardiovascular disease and death. The effect vascular calcification has on function during aging is not well understood. Emerging findings suggest vascular calcification can impact skeletal muscle perfusion, negatively affecting nutrient and oxygen delivery to skeletal muscle, ultimately accelerating muscle loss and functional decline. The present review summarizes existing evidence on the biological mechanisms linking vascular calcification with sarcopenia during aging.

Cognition, Brain Structure, and Brain Function in Individuals with Obesity and Related Disorders

PURPOSE OF REVIEW

Obesity is one of the most serious public health concerns. Excess adipose tissue, particularly with a centralized distribution, is associated with cognitive decline. Indeed, obesity has been associated with a number of adverse changes in brain function and structure that can be detected by neuroimaging techniques. These obesity-associated changes in the brain are associated with cognitive dysfunction.

RECENT FINDINGS

While the pathways by which excess adipose tissue affects brain function are not fully understood, available evidence points towards insulin resistance, inflammation, and vascular dysfunction, as possible mechanisms responsible for the observed relations between obesity and cognitive impairment. It appears that weight loss is related to better brain and cognitive outcomes and that cognitive impairment due to obesity may be reversible.

[Angiogenesis system, as a part of endothelial dysfunction in patients with diabetes mellitus type 2: relationship with obesity]

AIM

To investigate parameters of angiogenesis system in patients with diabetes mellitus and their relationship with obesity.

MATERIALS AND METHODS

104 patients with diabetes mellitus type 2 were included in the study. Patients were divided in 2 groups: Obesity+ (body mass index30 kg/m2;n=63) and Obesity- (body mass index 30 kg/m2;n=41). In all patients was performed clinico-diagnostical examination. mRNA expression levels of vascular endothelial growth factor (VEGF), its receptors flt-1 (fms-like tyrosine kinase 1), KDR (human kinase insert domain receptor) were determined in blood mononuclear cells.

RESULTS

There were no statistically significant differences in investigated parameters between study groups. mRNA expression level of VEGF was slightly lower in men compared to women: 0.19 (0.14; 0.32)vs0.28 (0.12; 0.4) respectively,р=0.2236. MRNA expression level of flt-1 was lower in men compared to women: 0.14 (0.04; 0.3)vs0.25 (0.12; 0.38),р=0.0321 (statistically significant). We found statistically significant correlations of mRNA expression level of VEGF with mRNA expression level of flt-1 and KDR. Also we found strong positive correlations of BMI and mRNA expression levels VEGF, flt-1, KDR (r=0.86107,r=0.86125,r=0.86112, respectively,p0.001).

CONCLUSION

Results of the study displayed relationship of obesity and angiogenesis system condition in patients with diabetes mellitus type 2. Further investigations are perspective for the future as a way to new therapeutical approach of obesity and its complications treatment.

Synergistic association of high-sensitivity C-reactive protein and body mass index with insulin resistance in non-diabetic adults

Epidemiological evidence has indicated that inflammatory markers and obesity are strongly correlated with insulin resistance (IR). However, there is a paucity of studies assessing the complex interaction between elevated hs-CRP and body mass index (BMI), particularly among Asians. This study investigated the additive interaction between hs-CRP and BMI on IR, using cross-sectional data from the 7th Korea National Health and Nutrition Examination Survey (2016–2018). A total of 5706 men and 6707 women aged 20 years or older were evaluated, and a multiple logistic regression analysis was used to assess the association of serum hs-CRP and BMI with IR, as measured by the triglyceride-glucose index (TyG index). Sex-specific median values were used to dichotomise the continuous TyG index variable into insulin-sensitive and IR categories. Biological interaction was evaluated using the Relative excess risk due to interaction (RERI), attributable proportion due to interaction (AP), and synergy index (SI). The joint effects of high hs-CRP and overweight/obesity on IR were greater than would be expected from the effects of the individual exposures alone. Relative to those with low hs-CRP and BMI < 23, having both exposures was related to increased IR with an adjusted OR of 2.97 (95% CI 2.50–3.52) in men and 3.08 (95% CI 2.67–3.56) in women with significant additive interactions. These findings demonstrate that IR prevention strategies that reduce both systematic inflammation and BMI may exceed the expected benefits based on targeting these risk factors separately.

Endothelial dysfunction due to selective insulin resistance in vascular endothelium: insights from mechanistic modeling

Previously, we have used mathematical modeling to gain mechanistic insights into insulin-stimulated glucose uptake. Phosphatidylinositol 3-kinase (PI3K)-dependent insulin signaling required for metabolic actions of insulin also regulates endothelium-dependent production of the vasodilator nitric oxide (NO). Vasodilation increases blood flow that augments direct metabolic actions of insulin in skeletal muscle. This is counterbalanced by mitogen-activated protein kinase (MAPK)-dependent insulin signaling in endothelium that promotes secretion of the vasoconstrictor endothelin-1 (ET-1). In the present study, we extended our model of metabolic insulin signaling into a dynamic model of insulin signaling in vascular endothelium that explicitly represents opposing PI3K/NO and MAPK/ET-1 pathways. Novel NO and ET-1 subsystems were developed using published and new experimental data to generate model structures/parameters. The signal-response relationships of our model with respect to insulin-stimulated NO production, ET-1 secretion, and resultant vascular tone, agree with published experimental data, independent of those used for model development. Simulations of pathological stimuli directly impairing only insulin-stimulated PI3K/Akt activity predict altered dynamics of NO and ET-1 consistent with endothelial dysfunction in insulin-resistant states. Indeed, modeling pathway-selective impairment of PI3K/Akt pathways consistent with insulin resistance caused by glucotoxicity, lipotoxicity, or inflammation predict diminished NO production and increased ET-1 secretion characteristic of diabetes and endothelial dysfunction. We conclude that our mathematical model of insulin signaling in vascular endothelium supports the hypothesis that pathway-selective insulin resistance accounts, in part, for relationships between insulin resistance and endothelial dysfunction. This may be relevant for developing novel approaches for the treatment of diabetes and its cardiovascular complications.

Intricacies of the endothelin system in human obesity: role in the development of complications and potential as a therapeutic target

Activation of the vascular endothelin-1 (ET-1) system is a key abnormality in vascular dysfunction of human obesity, especially in patients developing complications, such as the metabolic syndrome, diabetes, and atherosclerosis. Vascular insulin resistance, an increased insulin-stimulated endothelial production of ET-1 combined with impaired nitric oxide availability, is the hallmark of obesity-related vasculopathy, but dysregulated adipokine release from obese adipose tissue may contribute to the predominance of ET-1-dependent vasoconstriction. ET-1, in turn, might determine unhealthy obese adipose tissue expansion, with visceral and perivascular adipose tissue changes driving the release of inflammatory cytokines and atherogenic chemokines. In addition, ET-1 might also play a role in the development of the metabolic complications of obesity. Studies have shown inhibition of lipoprotein lipase activity by ET-1, with consequent hypertriglyceridemia. Also, ET-1 in pancreatic islets seems to contribute to beta cell dysfunction, hence affecting insulin production and development of diabetes. Moreover, ET-1 may play a role in nonalcoholic steatohepatitis. Recent clinical trials using innovative design have demonstrated that antagonism of ET-type A receptors protects against some complications of obesity and diabetes, such as nephropathy. These findings encourage further investigation to evaluate whether targeting the ET-1 system could afford better protection against other consequences of the obesity epidemic.

The association of low-density lipoprotein cholesterol with elevated arterial stiffness in adolescents and young adults with type 1 and type 2 diabetes: The SEARCH for Diabetes in Youth study

AIM

Our aim was to explore the relationship of Low-Density Lipoprotein Cholesterol (LDL-C) with subclinical cardiovascular disease (CVD) in youth with T1D and T2D. We hypothesized the association of LDL-C with elevated arterial stiffness (AS) would be partially accounted by the co-occurrence of other CVD factors.

METHOD

We included 1376 youth with T1D and 157 with T2D from the SEARCH study. CVD risk factors including LDL-C, waist to height ratio (WHtR), mean arterial pressure (MAP), HbA1c, albumin to creatinine ratio (ACR), and insulin sensitivity (IS) score were measured at both visits. At follow up, elevated carotid-femoral AS was defined as levels above 6.8 m/s. Multivariable logistic regression evaluated the odds of elevated AS as a function of the average CVD risk factors.

RESULTS

At follow up, age was 18.0 ± 4.1 and 21.6 ± 3.5 years and duration of diabetes was 7.8 ± 1.9 and 7.7 ± 1.9 years in T1D and T2D, respectively. Elevated AS was found in 8.4% of T1D and 49.0% of T2D participants. Each SD increase in LDL-C was associated with 1.28 increased odds (95% CI 1.05-1.54, P = .013) of elevated AS in youth with T1D. The association was similar but not statistically significant in T2D. WHtR, IS, and MAP were associated with elevated AS in both groups. Adjustment for WHtR or IS attenuated to non-significance the relationship between LDL-C and AS in T1D.

CONCLUSIONS

Obesity and insulin resistance attenuate the association of high LDL-C with AS suggesting they partially account for the adverse effects of LDL-C on cardiovascular health in youth with T1D.

Linagliptin, when compared to placebo, improves CD34+ve endothelial progenitor cells in type 2 diabetes subjects with chronic kidney disease taking metformin and/or insulin: a randomized controlled trial

BACKGROUND

Endothelial Progenitor cells (EPCs) has been shown to be dysfunctional in both type 2 diabetes mellitus (T2DM) and chronic kidney disease (CKD) leading to poor regeneration of endothelium and renal perfusion. EPCs have been shown to be a robust cardiovascular disease (CVD) risk indicator. Cellular mechanisms of DPP4 inhibitors such as linagliptin (LG) on CVD risk, in patients with T2DM with established CKD has not been established. Linagliptin, a DPP4 inhibitor when added to insulin, metformin or both may improve endothelial dysfunction in a diabetic kidney disease (DKD) population.

METHODS

31 subjects taking metformin and/or Insulin were enrolled in this 12 weeks, double blind, randomized placebo matched trial, with 5 mg LG compared to placebo. Type 2 diabetes subjects (30-70 years old), HbA1c of 6.5-10%, CKD Stage 1-3 were included. CD34+ cell number, migratory function, gene expression along with vascular parameters such as arterial stiffness, biochemistry, resting energy expenditure and body composition were measured. Data were collected at week 0, 6 and 12. A mixed model regression analysis was done with p value < 0.05 considered significant.

RESULTS

A double positive CD34/CD184 cell count had a statistically significant increase (p < 0.02) as determined by flow cytometry in LG group where CD184 is SDF1a cell surface receptor. Though mRNA differences in CD34+ve was more pronounced CD34- cell mRNA analysis showed increase in antioxidants (superoxide dismutase 2 or SOD2, Catalase and Glutathione Peroxidase or GPX) and prominent endothelial markers (PECAM1, VEGF-A, vWF and NOS3). Arterial stiffness measures such as augmentation Index (AI) (p < 0.04) and pulse wave analysis (PWV) were improved (reduced in stiffness) in LG group. A reduction in LDL: HDL ratio was noted in treatment group (p < 0.04). Urinary exosome protein examining podocyte health (podocalyxin, Wilms tumor and nephrin) showed reduction or improvement.

CONCLUSIONS

In DKD subjects, Linagliptin promotes an increase in CXCR4 expression on CD34 + progenitor cells with a concomitant improvement in vascular and renal parameters at 12 weeks. Trial Registration Number NCT02467478 Date of Registration: 06/08/2015.

Effect of Bariatric Surgery on Cardiovascular Events and Metabolic Outcomes in Obese Patients with Insulin-Treated Type 2 Diabetes: a Retrospective Cohort Study

AIMS

To compare non-fatal cardiovascular (CV) events and metabolic outcomes, among obese patients with insulin-treated type 2 diabetes who underwent bariatric surgery compared with a propensity-matched non-bariatric cohort.

METHODS

A retrospective cohort study was conducted among 11,125 active patients with type 2 diabetes from The Health Improvement Network (THIN) database. Propensity score matching (up to 1:6 ratio) was used to identify patients who underwent bariatric surgery (N = 131) with a non-bariatric cohort (N = 579). Follow-up was undertaken for 10 years (9686 person-years) to compare differences in metabolic outcomes and CV risk events that included the following: acute myocardial infarction (AMI), stroke, coronary heart disease (CHD), heart failure (HF) and peripheral artery disease (PAD). Cox proportional regression was used to compute the outcomes between groups.

RESULTS

The mean age was 52 (SD 13) years (60% female); the baseline weight and BMI were 116 (SD 25) kg and 41 (SD 9) kg/m², respectively. Significant reductions in weight and BMI were observed in bariatric group during 10 years of follow-up. Bariatric surgery had a significant cardioprotective effect by reducing the risk of non-fatal CHD (adjusted hazard ratio [aHR] 0.29, 95% CI 0.16-0.52, p < 0.001) and PAD events (aHR 0.31, 95% CI 0.11-0.89, p = 0.03). However, the surgery had no significant effect on AMI (aHR 0.98, p = 0.95), stroke (HR 0.87, p = 0.76) and HF (HR 0.89, p = 0.73) risks. Bariatric surgery had favourable effects on insulin independence, HbA1c and BP.

CONCLUSION

Among obese insulin-treated patients with type 2 diabetes, bariatric surgery is associated with significant reductions in non-fatal CHD and PAD events, lower body weight, HbA1c, BP and a greater likelihood of insulin independency during 10 years of follow-up.

Effects of high doses of glucocorticoids on insulin-mediated vasodilation in the mesenteric artery of rats

Several pathological conditions predict the use of glucocorticoids for the management of the inflammatory response; however, chronic or high dose glucocorticoid treatment is associated with hyperglycemia, hyperlipidemia, and insulin resistance and can be considered a risk factor for cardiovascular disease. Therefore, we investigated the mechanisms involved in the vascular responsiveness and inflammatory profile of mesenteric arteries of rats treated with high doses of glucocorticoids. Wistar rats were divided into a control (CO) group and a dexamethasone (DEX) group, that received dexamethasone for 7 days (2mg/kg/day, i.p.). Blood samples were used to assess the lipid profile and insulin tolerance. Vascular reactivity to Phenylephrine (Phe) and insulin, and O2•-production were evaluated. The intracellular insulin signaling pathway PI3K/AKT/eNOS and MAPK/ET-1 were investigated. Regarding the vascular inflammatory profile, TNF-α, IL-6, IL-1β and IL-18 were assessed. Dexamethasone-treated rats had decreased insulin tolerance test and endothelium-dependent vasodilation induced by insulin. eNOS inhibition caused vasoconstriction in the DEX group, which was abolished by the ET-A antagonist. Insulin-mediated relaxation in the DEX group was restored in the presence of the O2.- scavenger TIRON. Nevertheless, in the DEX group there was an increase in Phe-induced vasoconstriction. In addition, the intracellular insulin signaling pathway PI3K/AKT/eNOS was impaired, decreasing NO bioavailability. Regarding superoxide anion generation, there was an increase in the DEX group, and all measured proinflammatory cytokines were also augmented in the DEX group. In addition, the DEX-group presented an increase in low-density lipoprotein cholesterol (LDL-c) and total cholesterol (TC) and reduced high-density lipoprotein cholesterol (HDL-c) levels. In summary, treatment with high doses of dexamethasone promoted changes in insulin-induced vasodilation, through the reduction of NO bioavailability and an increase in vasoconstriction via ET-1 associated with generation of O2•- and proinflammatory cytokines.

Diabetes and atherothrombosis: The circadian rhythm and role of melatonin in vascular protection

Obesity-related euglycaemic insulin resistance clusters with cardiometabolic risk factors, contributing to the development of both type 2 diabetes and cardiovascular disease. An increased thrombotic tendency in diabetes stems from platelet hyperactivity, enhanced activity of prothrombotic coagulation factors and impaired fibrinolysis. Furthermore, a low-grade inflammatory response and increased oxidative stress accelerate the atherosclerotic process and, together with an enhanced thrombotic environment, result in premature and more severe cardiovascular disease. The disruption of circadian cycles in man secondary to chronic obesity and loss of circadian cues is implicated in the increased risk of developing diabetes and cardiovascular disease. Levels of melatonin, the endogenous synchronizer of circadian rhythm, are reduced in individuals with vascular disease and those with deranged glucose metabolism. The anti-inflammatory, antihypertensive, antioxidative and antithrombotic activities of melatonin make it a potential therapeutic agent to reduce the risk of vascular occlusive disease in diabetes. The mechanisms behind melatonin-associated reduction in procoagulant response are not fully known. Current evidence suggests that melatonin inhibits platelet aggregation and might affect the coagulation cascade, altering fibrin clot structure and/or resistance to fibrinolysis. Large-scale clinical trials are warranted to investigate the effects of modulating the circadian clock on insulin resistance, glycaemia and cardiovascular outcome.

The relationship between urinary albumin excretion, cardiovascular outcomes and total mortality among a large cohort of insulin-treated patients with type 2 diabetes in routine primary care practices

Background

Albuminuria is a recognized diagnostic and prognostic marker of chronic kidney disease and cardiovascular (CV) risk but the well-known relationship between increments in urinary albumin:creatinine ratio (UACR) and CV outcomes and mortality has not been fully explored in insulin-treated patients with type 2 diabetes (T2D) in routine clinical care.

Methods

We investigated data for insulin users with T2D from UK general practices between 2007 and 2014. The UACR at the time of insulin initiation was measured and categorized as &lt;10, 10– 29, 30–300 and &gt;300 mg/g. Patients were followed up for 5 years or the earliest occurrence of all-cause mortality, non-fatal myocardial infarction or stroke. Cox proportional hazards models were fitted to estimate the risk of a composite of these events.

Results

A total of 12 725 patients with T2D (mean age 58.6 ± 13.8 years, mean haemoglobin A1c 8.7 ± 1.8%) initiating insulin therapy between 2007 and 2014 met the inclusion criteria. Compared with patients whose ACR levels at insulin initiation were &lt;10 mg/g, the adjusted risk of the 3-point composite endpoint was 9, 30 and 98% higher in those with ACR levels between 10–29, 30–300 and &gt;300 mg/g, respectively, after a follow-up period of 5 years. The ACR category on its own did not predict risk of all-cause mortality.

Conclusions

This study shows that in patients with T2D on insulin therapy, increased urinary ACR is independently associated with an increased risk of major adverse CV events and all-cause mortality.

Serum insulin levels are associated with vulnerable plaque components in the carotid artery: the Rotterdam Study

BACKGROUND

To investigate the association between fasting serum insulin and glucose levels with atherosclerotic plaque composition in the carotid artery. Impaired insulin and glucose levels are implicated in the etiology of cardiovascular disease; however, their influence on the formation and composition of atherosclerotic plaque remains unclear.

METHODS

In 1740 participants (mean age 72.9 years, 46% women, 14.4% diabetes mellitus) from the population-based Rotterdam Study, we performed carotid MRI to evaluate the presence of calcification, lipid core, and intraplaque hemorrhage in carotid atherosclerosis. All participants also underwent blood sampling to obtain information on serum insulin and glucose levels. Using logistic regression models, we assessed the association of serum insulin and glucose levels (per s.d. and in tertiles) with the different plaque components, while adjusting for sex, age, intima-media thickness, and cardiovascular risk factors.

RESULTS

Serum insulin levels were associated with the presence of intraplaque hemorrhage (adjusted odds ratio (OR): 1.42 (95% CI: 1.12-1.7)) We found no association with the presence of calcification or lipid core. Sensitivity analyses restricted to individuals without diabetes mellitus yielded similar results. No associations were found between serum glucose levels and any of the plaque components.

CONCLUSIONS

Serum insulin levels are associated with the presence of vulnerable components of carotid plaque, specifically with intraplaque hemorrhage. These findings suggest a complex role for serum insulin in the pathophysiology of carotid atherosclerosis and in plaque vulnerability.

Causal relationships between lipid and glycemic levels in an Indian population: A bidirectional Mendelian randomization approach

BACKGROUND

Dyslipidemia and abnormal glycemic traits are leading causes of morbidity and mortality. Although the association between the two traits is well established, there still exists a gap in the evidence for the direction of causality.

OBJECTIVE

This study aimed to examine the direction of the causal relationship between lipids and glycemic traits in an Indian population using bidirectional Mendelian randomization (BMR).

METHODS

The BMR analysis was conducted on 4900 individuals (2450 sib-pairs) from the Indian Migration Study. Instrument variables were generated for each lipid and glycemic trait (fasting insulin, fasting glucose, HOMA-IR, HOMA-β, LDL-cholesterol, HDL-cholesterol, total cholesterol and triglycerides) to examine the causal relationship by applying two-stage least squares (2SLS) regression in both directions.

RESULTS

Lipid and glycemic traits were found to be associated observationally, however, results from 2SLS showed that only triglycerides, defined by weighted genetic risk score (wGRS) of 3 SNPs (rs662799 at APOAV, rs780094 at GCKR and rs4420638 at APOE/C1/C4), were observed to be causally effecting 1.15% variation in HOMA-IR (SE = 0.22, P = 0.010), 1.53% in HOMA- β (SE = 0.21, P = 0.001) and 1.18% in fasting insulin (SE = 0.23, P = 0.009). No evidence for a causal effect was observed in the reverse direction or between any other lipid and glycemic traits.

CONCLUSION

The study findings suggest that triglycerides may causally impact various glycemic traits. However, the findings need to be replicated in larger studies.

The Association Between Femoral Artery Intima-Media Thickness and Serum Glucagon-Like Peptide-1 Levels Among Newly Diagnosed Patients with Type 2 Diabetes Mellitus

INTRODUCTION

Endothelium dysfunction and decrease of incretin effects occur early in type 2 diabetes mellitus and these changes contribute to diabetic cardiovascular complications such as atherosclerosis, thick intima-media, coronary, and peripheral arterial diseases. In patients with diabetes, the femoral artery is a site of a high incidence of injury in peripheral vascular diseases, and atherosclerotic changes may appear earlier in the femoral artery compared to the carotid artery. This study was conducted to determine the prevalence of increased femoral artery intima-media thickness (IMT) and atherosclerotic plaque and their correlation with serum glucagon-like peptide-1 (GLP-1) levels in newly-diagnosed patients with type 2 diabetes mellitus.

MATERIALS AND METHODS

A cross-sectional study was conducted on 332 patients with nT2D in the National Endocrinology Hospital, Vietnam from January 2015 to May 2018. IMT was measured by Doppler ultrasound and GLP-1 by enzyme-linked immunosorbent assay (ELISA). All data were analyzed with SPSS version 26 for Windows (SPSS Inc, Chicago, IL).

RESULTS

Prevalence of thick femoral artery IMT and atherosclerotic plaque was 38.2 and 22.3%, respectively. There was a relationship between IMT and age, waist to hip ratio (WHR), systolic blood pressure (SBP), diastolic blood pressure (DBP), fasting GLP-1, high sensitive CRP (hsCRP) and 24-hour microalbuminuria secretion (24-h MAUS). The fasting serum GLP-1 (fGLP-1) levels were reduced significantly in patients with thickness and atherosclerosis femoral artery (p = 0.001). After adjusting with other related factors, namely, DBP and estimated glomerular filtration rate (eGFR), whilst hsCRP and 24-h MAUS showed a significantly positive correlation to IMT (Standardized B and p of 0.242, 0.004 and 0.178, 0.043, respectively), fGLP-1 showed a significantly negative correlation to IMT (Standardized B = -0.288, p = 0.001).

CONCLUSION

Among n2TD, the percentage for femoral artery thick IMT and atherosclerosis was 38.2% and 22.3% respectively, and serum GLP-1 was negatively correlated with thick IMT and atherosclerosis.

The Role of Protein Tyrosine Phosphatase (PTP)-1B in Cardiovascular Disease and Its Interplay with Insulin Resistance

Endothelial dysfunction is a key feature of cardiovascular disorders associated with obesity and diabetes. Several studies identified protein tyrosine phosphatase (PTP)-1B, a member of the PTP superfamily, as a major negative regulator for insulin receptor signaling and a novel molecular player in endothelial dysfunction and cardiovascular disease. Unlike other anti-diabetic approaches, genetic deletion or pharmacological inhibition of PTP1B was found to improve glucose homeostasis and insulin signaling without causing lipid buildup in the liver, which represents an advantage over existing therapies. Furthermore, PTP1B was reported to contribute to cardiovascular disturbances, at various molecular levels, which places this enzyme as a unique single therapeutic target for both diabetes and cardiovascular disorders. Synthesizing selective small molecule inhibitors for PTP1B is faced with multiple challenges linked to its similarity of sequence with other PTPs; however, overcoming these challenges would pave the way for novel approaches to treat diabetes and its concurrent cardiovascular complications. In this review article, we summarized the major roles of PTP1B in cardiovascular disease with special emphasis on endothelial dysfunction and its interplay with insulin resistance. Furthermore, we discussed some of the major challenges hindering the synthesis of selective inhibitors for PTP1B.

Burden of Cardiovascular Risk Factors Over Time and Arterial Stiffness in Youth With Type 1 Diabetes Mellitus: The SEARCH for Diabetes in Youth Study

Background The incidence of type 1 diabetes mellitus (T1DM) in children is increasing, resulting in higher burden of cardiovascular diseases due to diabetes mellitus-related vascular dysfunction. Methods and Results We examined cardiovascular risk factors ( CVRF s) and arterial parameters in 1809 youth with T1DM. Demographics, anthropometrics, blood pressure, and laboratory data were collected at T1DM onset and 5 years later. Pulse wave velocity and augmentation index were collected with tonometry. ANOVA or chi-square tests were used to test for differences in measures of arterial parameters by CVRF . Area under the curve of CVRF s was entered in general linear models to explore determinants of accelerate vascular aging. Participants at the time of arterial measurement were 17.6±4.5 years old, 50% female, 76% non-Hispanic white, and duration of T1DM was 7.8±1.9 years. Glycemic control was poor (glycated hemoglobin, 9.1±1.8%). All arterial parameters were higher in participants with glycated hemoglobin ≥9% and pulse wave velocity was higher with lower insulin sensitivity or longer duration of diabetes mellitus. Differences in arterial parameters were found by sex, age, and presence of obesity, hypertension, or dyslipidemia. In multivariable models, higher glycated hemoglobin, lower insulin sensitivity, body mass index, blood pressure, and lipid areas under the curve were associated with accelerated vascular aging. Conclusions In young people with T1DM, persistent poor glycemic control and higher levels of traditional CVRF s are independently associated with arterial aging. Improving glycemic control and interventions to lower CVRF s may prevent future cardiovascular events in young individuals with T1DM.

Effects of Resistance and Combined training on Vascular Function in Type 2 Diabetes: A Systematic Review of Randomized Controlled Trials

BACKGROUND

Cardiovascular disease (CVD) is the main cause of mortality in type 2 diabetes (T2D). Exercise can reduce the risk factors associated with CVD in T2D patients. However, research evaluating its beneficial effects in these patients has used different measurement protocols and types of exercise, complicating comparison.

AIM

To assess the effects of resistance training (RT) and combined training (CT) on the vascular function of T2D patients.

METHODS

A database search (MEDLINE, Scopus, and Web of Science) was performed to identify relevant articles that were published up to August 2017. Only original studies evaluating the effects of RT or CT interventions on vascular function in T2D patients were included. The articles were reviewed independently by at least three reviewers. The Cochrane guidelines were used to assess the methodological quality of the studies. Fourteen studies were finally included. Two studies only used RT and twelve studies used CT as intervention strategy.

RESULTS AND CONCLUSIONS

The results show that resistance training is a useful means for primary treatment of vascular diseases and maintenance of vascular function in T2D patients. However, more studies are necessary to gain full knowledge of the beneficial effects and to identify tailored exercise plans to optimize these benefits. The information provided in this review may help to improve current treatment of vascular diseases in T2D patients and to design future studies.

Individual and Combined Relationship between Reduced eGFR and/or Increased Urinary Albumin Excretion Rate with Mortality Risk among Insulin-Treated Patients with Type 2 Diabetes in Routine Practice

Background

A low estimated glomerular filtration rate (eGFR) and an increased urinary albumin-to-creatinine ratio (ACR) are well-recognised prognostic markers of cardiovascular (CV) risk, but their individual and combined relationship with CV disease and total mortality among insulin-treated type 2 diabetes (T2D) patients in routine clinical care is unclear.

Methods

We analysed data for insulin users with T2D from UK general practices between 2007 and 2014 and examined the association between mortality rates and chronic kidney disease [categorised by low eGFR (< 60 mL/min/1.73 m²), high eGFR (≥60 mL/min/1.73 m²), low ACR (< 300 mg/g); and high ACR (≥300 mg/g) at insulin initiation] after a 5-year follow-up period using Cox proportional hazard models.

Results

A total of 18,227 patients were identified (mean age: 61.5 ± 13.8 years, mean HbA1c: 8.6 ± 1.8%). After adjusting for confounders, when compared to adults on insulin therapy with an eGFR < 60 and an ACR ≥300 (low eGFR + high ACR) after a follow-up period of 5 years, patients with an eGFR < 60 and an ACR < 300 (low eGFR + low ACR) had a 6% lower mortality rate (aHR: 0.94; 95% CI 0.79-1.12); those with an eGFR > 60 and an ACR ≥300 (high eGFR + high ACR) had a 20% lower mortality rate (aHR: 0.80; 95% CI 0.68-0.96); and those with an eGFR > 60 and an ACR < 300 (high eGFR + low ACR) had the lowest death rate (28% less; aHR: 0.72; 95% CI 0.59-0.87).

Conclusion

This study shows that among a large cohort of insulin-treated T2D patients in routine practice, the combination of reduced eGFR with increased ACR was associated with the greatest risk of premature death, followed closely by those with reduced eGFR and normal ACR levels. Adoption of aggressive CV risk management strategies to reduce mortality in patients with a low eGFR and albuminuria is essential in high-risk patients with T2D.

Increased endothelin-1-mediated vasoconstrictor tone in human obesity: effects of gut hormones

The heavy impact of obesity on the development and progression of cardiovascular disease has sparked sustained efforts to uncover the mechanisms linking excess adiposity to vascular dysfunction. Impaired vasodilator reactivity has been recognized as an early hemodynamic abnormality in obese patients, but also increased vasoconstrictor tone importantly contributes to their vascular damage. In particular, upregulation of the endothelin (ET)-1 system, consistently reported in these patients, might accelerate atherosclerosis and its complication, given the pro-inflammatory and mitogenic properties of ET-1. In recent years, a number of gut hormones, in addition to their role as modulators of food intake, energy balance, glucose and lipid metabolism, and insulin secretion and action, have demonstrated favorable vascular actions. They increase the bioavailability of vasodilator mediators like nitric oxide, but they have also been shown to inhibit the ET-1 system. These features make gut hormones promising tools for targeting both the metabolic and cardiovascular complications of obesity, a view supported by recent large-scale clinical trials indicating that novel drugs for type 2 diabetes with cardiovascular potential may translate into clinically significant advantages. Therefore, there is real hope that better understanding of the properties of gut-derived substances might provide more effective therapies for the obesity-related cardiometabolic syndrome.

Impact of a group-based treatment program on adipocytokines, oxidative status, inflammatory cytokines and arterial stiffness in obese children and adolescents

Background Dysregulation of adipocytokines, inflammatory cytokines and oxidative stress are associated with the pathogenesis of obesity-related complications. This study aimed to evaluate the effect of a group-based lifestyle modification program on adipocytokines, inflammatory cytokines, oxidative status and arterial stiffness in obese youth. Methods A 1-year weight-reduction program was conducted. The program consisted of initial hospitalization and five outpatient group-based sessions held at 1, 2, 3, 6 and 9 months. Pre- and post-intervention measurements included anthropometric data, blood tests, body composition and brachial-ankle pulse wave velocity (ba-PWV). Results A total of 126 obese youths were recruited, and 115 of those completed the study. Twenty-four participants had increased percentage weight for height at the end of the study (group A), 30 had minimal reduction (group B) and 61 had substantial reduction (group C). Lean mass significantly increased in all three groups (all p<0.001). A significant decrease in leptin (group A, p=0.021; group B, p=0.005; group C, p<0.001), interleukin-6 (IL-6) (group A, p=0.019; group B, p=0.004; group C, p<0.001) and ba-PWV (group A, p=0.031; group B, p=0.015; group C, p<0.001) was also observed. No significant change in the oxidative status was found among the groups. Reduction in ba-PWV was correlated with decreases in plasma malondialdehyde (pMDA) (r=0.233, p=0.036) and homeostasis model assessment of insulin resistance (HOMA-IR) (r=0.253, p=0.025). Conclusions A group-based healthy lifestyle program for obese youths had beneficial effects on adipocytokines, inflammatory cytokines and arterial stiffness. Participants without change in weight status also benefited. These improvements may reduce the risk of obese youths developing atherosclerosis.