Does Elevated Glucose Promote Atherosclerosis? Pros and Cons

Molecular and Pathophysiological Mechanisms Leading to Ischemic Heart Disease in Patients with Diabetes Mellitus

Coronary atherosclerosis in patients with diabetes mellitus is the most significant pathophysiological mechanism responsible for ischemic heart disease. Atherosclerosis in diabetes is premature, more diffuse, and more progressive, and it affects more coronary blood vessels compared to non-diabetics. Atherosclerosis begins with endothelial dysfunction, continues with the formation of fatty streaks in the intima of coronary arteries, and ends with the appearance of an atherosclerotic plaque that expands centrifugally and remodels the coronary artery. If the atherosclerotic plaque is injured, a thrombus forms at the site of the damage, which can lead to vessel occlusion and potentially fatal consequences. Diabetes mellitus and atherosclerosis are connected through several pathological pathways. Among the most significant factors that lead to atherosclerosis in diabetics are hyperglycemia, insulin resistance, oxidative stress, dyslipidemia, and chronic inflammation. Chronic inflammation is currently considered one of the most important factors in the development of atherosclerosis. However, to date, no adequate anti-inflammatory therapeutic measures have been found to prevent the progression of the atherosclerotic process, and they remain a subject of ongoing research. In this review, we summarize the most significant pathophysiological mechanisms that link atherosclerosis and diabetes mellitus.

AGE induced macrophage-derived exosomes induce endothelial dysfunction in diabetes via miR-22-5p/FOXP1

BACKGROUND

Endothelial dysfunction is a pivotal contributor to cardiovascular complications in individuals with diabetes. However, the precise role of macrophages and their exosomes in the diabetic milieu remains elusive.

METHODS

Exosomes (Exos) were isolated from the supernatants of macrophages treated with advanced glycation end products (AGE) or bovine serum albumin (BSA) using ultracentrifugation. Following coculture with AGE-Exos or BSA-Exos, human umbilical vein endothelial cells (HUVECs) were subjected to CCK-8, EdU, cell migration, monocyte adhesion, and tube formation assays. ELISA and Western blotting were employed to assess inflammatory cytokine release and protein expression levels in HUVECs. The miRNA expression profiles of AGE-Exos and BSA-Exos were analysed using miRNA arrays. Potential targets of miR-22-5p were predicted via miRNA databases and validated through RT‒qPCR, dual-luciferase reporter assays, and rescue experiments. Furthermore, a Rab27a knockout mouse model of type 2 diabetes mellitus (T2DM) was established by intraperitoneal injection of Streptozotocin. Aortic tissues were analysed via immunofluorescence for CD63 and CD31 expression, immunohistochemistry for VCAM-1 and ICAM-1 expression, and Western blotting for FOXP1 expression.

RESULTS

AGE stimulation increased the secretion of exosomes from macrophages. Compared with BSA-Exos, AGE-Exos significantly impaired endothelial cell proliferation, migration, and tube formation capabilities while increasing monocyte adhesion and proinflammatory cytokine release without affecting cell viability. miR-22-5p was enriched in AGE-Exos, which were subsequently transferred to HUVECs, specifically targeting FOXP1, resulting in endothelial dysfunction. Overexpression of miR-22-5p in HUVECs using lentiviral vectors recapitulated the inflammatory effects observed with AGE-Exos, whereas anti-miR-22-5p conferred protective effects. Rab27a knockout significantly reduced exosome accumulation in T2DM model mouse aortic tissues, alleviating endothelial discontinuity, downregulating VCAM-1 and ICAM-1 expression, and upregulating FOXP1 expression.

CONCLUSIONS

AGE-induced release of macrophage-derived exosomes may partially depend on Rab27a transport, which delivers miR-22-5p to ECs. This miR-22-5p targets FOXP1 in ECs, leading to inflammation and resulting in endothelial dysfunction that accelerates the development of diabetic vascular lesions.

Updated evidence on cardiovascular and renal effects of GLP-1 receptor agonists and combination therapy with SGLT2 inhibitors and finerenone: a narrative review and perspectives

Glucagon-like peptide-1 receptor agonists (GLP-1RAs) have a reliable hypoglycaemic and weight-loss effect that can intervene in obesity, which is the basis of type 2 diabetes pathology. GLP-1RA therapy has shown potential benefits in reducing the risk of major adverse cardiovascular events and improving kidney outcomes in patients with diabetes at high risk for cardiovascular disease. More recent evidence is expanding their benefits to heart failure with preserved ejection fraction and clinically important renal outcomes in patients with and without diabetes. Some sub-analyses of large clinical trials suggest that GLP-1RA and sodium-glucose cotransporter 2 inhibitor combination therapy may provide more significant reductions in heart failure hospitalization and renal composite events than each alone. Moreover, the addition of finerenone to this combination therapy could potentially provide stronger cardiorenal protective benefits. Further studies are needed to assess the potential cardiovascular and renal benefits of combination therapy and to determine suitable patient population for the therapy.

The Role of Natural Low Molecular Weight Dicarbonyls in Atherogenesis and Diabetogenesis

This review summarises the data from long-term experimental studies and literature data on the role of oxidatively modified low-density lipoproteins (LDL) in atherogenesis and diabetogenesis. It was shown that not "oxidized" (lipoperoxide-containing) LDL, but dicarbonyl-modified LDL are atherogenic (actively captured by cultured macrophages with the help of scavenger receptors), and also cause expression of lectin like oxidized low density lipoprotein receptor 1 (LOX-1) and nicotinamide adenine dinucleotide phosphate (NADPH) oxidase 1 (NOX-1) genes in endotheliocytes, which stimulate apoptosis and endothelial dysfunction. The obtained data allowed us to justify new approaches to pharmacotherapy of atherosclerosis and diabetes mellitus.

Temporal relationships between blood glucose, lipids and BMI, and their impacts on atherosclerosis: a prospective cohort study

OBJECTIVES

This study aimed to explore the temporal relationship between blood glucose, lipids and body mass index (BMI), and their impacts on atherosclerosis (AS).

DESIGN

A prospective cohort study was designed.

SETTING AND PARTICIPANTS

A total of 2659 subjects from Harbin Cohort Study on Diet, Nutrition and Chronic Non-communicable Diseases, and aged from 20 to 74 years were included.

PRIMARY AND SECONDARY OUTCOME MEASURES

Body weight, height, fasting blood glucose (FBG) and 2-hour postprandial glucose (2-h PG), blood lipids including total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-c) and high-density lipoprotein cholesterol (HDL-c) were measured at baseline and follow-up. Brachial ankle pulse wave velocity (baPWV) was examined at follow-up as a marker of AS risk. Logistic regression analysis, cross-lagged path analysis and mediation analysis were performed to explore the temporal relationships between blood glucose, lipids and BMI, and their impacts on AS risk.

RESULTS

Logistic regression analysis indicated that increased FBG, 2-h PG, TC, TG, LDL-c and BMI were positively associated with AS risk, while increased HDL-c was negatively associated with AS risk. The path coefficients from baseline blood parameters to the follow-up BMI were significantly greater than those from baseline BMI to the follow-up blood parameters. Mediation analysis suggested that increased FBG, 2-h PG, TC, TG and LDL-c could increase AS risk via increasing BMI, the effect intensity from strong to weak was LDL-c>TC>TG>FBG>2 h PG, while increased HDL-c could decrease AS risk via decreasing BMI.

CONCLUSIONS

Changes in blood glucose and lipids could cause change in BMI, which mediated the impacts of blood glucose and lipids on AS risk. These results highlight the importance and provide support for the early and comprehensive strategies of AS prevention and control.

Association between cardiovascular health and abdominal aortic calcification: Analyses of NHANES 2013-2014

BACKGROUND

Abdominal aortic calcification (AAC) is closely connected to cardiovascular disease. We aimed to measure the association between cardiovascular health (CVH) levels, assessed by the Life's Essential 8 (LE8) score, and AAC within a nationally representative sample of the US.

METHODS

The National Health and Nutrition Examination Survey 2013-2014 participants were chosen for this cross-sectional investigation. LE8 scores, ranging from 0 to 100, were calculated according to the criteria outlined by the American Heart Association. AAC was evaluated using a semi-quantitative scoring system known as AAC-24. Weighted linear regression, multivariate logistic regression, and restricted cubic spline models were used to investigate the correlations. Subgroup analysis and interaction tests were conducted to assess this association's robustness across different population groups.

RESULTS

Increased CVH levels were associated with diminished AAC scores and a reduced prevalence of severe AAC. In the partially adjusted model, each unit increase in LE8 score was associated with a 2% decrease in severe AAC prevalence [OR 0.98; 95% CI 0.96, 0.99]. Participants in the high CVH level group experienced a 72% reduced prevalence of severe AAC compared to those in the low CVH level group in model 2 [OR 0.28; 95% CI 0.12, 0.63]. This inverse association was notably more prominent in adults aged 60 years and above.

CONCLUSIONS

CVH exhibited a robust negative correlation with AAC. Promoting optimal CVH levels may favor averting AAC within the general population.

Supplementing Glucose Intake Reverses the Inflammation Induced by a High-Fat Diet by Increasing the Expression of Siglec-E Ligands on Erythrocytes

Siglec-9/E is a cell surface receptor expressed on immune cells and can be activated by sialoglycan ligands to play an immunosuppressive role. Our previous study showed that increasing the expression of Siglec-9 (the human paralog of mouse Siglec-E) ligands maintains functionally quiescent immune cells in the bloodstream, but the biological effects of Siglec-9 ligand alteration on atherogenesis were not further explored. In the present study, we demonstrated that the atherosclerosis risk factor ox-LDL or a high-fat diet could decrease the expression of Siglec-9/E ligands on erythrocytes. Increased expression of Siglec-E ligands on erythrocytes caused by dietary supplementation with glucose (20% glucose) had anti-inflammatory effects, and the mechanism was associated with glucose intake. In high-fat diet-fed apoE-/- mice, glucose supplementation decreased the area of atherosclerotic lesions and peripheral inflammation. These data suggested that increased systemic inflammation is attenuated by increasing the expression of Siglec-9/E ligands on erythrocytes. Therefore, Siglec-9/E ligands might be valuable targets for atherosclerosis therapy.

In Association with Other Risk Factors, Smoking Is the Main Predictor for Lower Transcutaneous Oxygen Pressure in Type 2 Diabetes

Type 2 diabetes mellitus (T2DM) significantly increases the risk of peripheral artery disease (PAD), and diabetes is the leading cause of nontraumatic amputations. This study investigated the risk factors for transcutaneous oxygen pressure (TcPO2) in T2DM, a noninvasive method to quantify skin oxygenation and the underlying microvascular circulation. The study included 119 T2DM patients (91 male/28 female). TcPO2 measurements were conducted with the Tina TCM4 Series transcutaneous monitor (Radiometer, Copenhagen, Sweden) and skin electrodes. Patients with TcPO2 < 40 mmHg were younger (p = 0.001), had significantly higher systolic blood pressure (SBP) (p = 0.023), glycated hemoglobin (HbA1c) (p = 0.013), fasting plasma glucose (fPG) (p = 0.038), total cholesterol (p = 0.006), LDL cholesterol (p = 0.004), and had more frequent smoking habits (p = 0.001) than those with TcPO2 ≥ 40 mmHg. The main predictors for the TcPO2 value (R2 = 0.211) obtained via stepwise regression analysis were age, smoking, SBP, HbA1c, fPG, and total and LDL cholesterol. Among all the listed predictors, smoking, HbA1c, and LDL cholesterol were found to be the most significant, with negative parameter estimates of -3.051310 (p = 0.0007), -2.032018 (p = 0.0003), and -2.560353 (p = 0.0046). The results of our study suggest that in association with other risk factors, smoking is the main predictor for lower TcPO2 in T2DM.

Risk Factors for Medial and Intimal Intracranial Internal Carotid Artery Calcification in Men and Women with Cardiovascular Disease: The UCC-SMART Study

INTRODUCTION

Calcifications of the intracranial internal carotid artery (iICA) can lead to an increased risk for stroke. Two types of iICA calcification are known: those affecting the tunica intima or the tunica media. In extracranial arteries, risk factors and calcification patterns are different in women and men, but little is known regarding the iICA. In this study, we aimed to identify sex-specific risk profiles and medications associated to intimal and medial iICA calcification in patients with cardiovascular disease (CVD).

METHODS

Participants of the UCC-SMART cohort undergoing a non-contrast head CT within 6 months from the study inclusion were considered (n = 475). Intimal or medial iICA calcification pattern was assessed using a previously histology-validated method. Sex-stratified associations between calcification pattern and cardiovascular risk factors, laboratory parameters, and medication use were calculated using Poisson regression analysis with robust standard errors.

RESULTS

Two hundred and four women and 271 men (age range 24-79 years) were included. 45.4% of men and 34.8% of women showed intimal iICA calcification, while 28.4% of men and 24.0% of women showed medial iICA calcification. Minimal or no iICA calcification was observed in 26.2% of men and in 41.2% of women (reference group). Older age was associated with both calcification patterns in women and men. In women, use of vitamin K antagonists and lipid-lowering drugs was associated to medial calcification, while systolic blood pressure and glucose levels were associated to intimal calcification. In men, current smoking was associated to intimal calcification.

CONCLUSIONS

Women and men with CVD show differences in risk profiles and medication use associated to intimal and medial iCA calcification.

Key Therapeutic Targets to Treat Hyperglycemia-Induced Atherosclerosis Analyzed Using a Petri Net-Based Model

Chronic superphysiological glucose concentration is a hallmark of diabetes mellitus (DM) and a cause of damage to many types of cells. Atherosclerosis coexists with glucose metabolism disturbances, constituting a significant problem and exacerbating its complications. Atherosclerosis in DM is accelerated, so it is vital to slow its progression. However, from the complex network of interdependencies, molecules, and processes involved, choosing which ones should be inhibited without blocking the pathways crucial for the organism's functioning is challenging. To conduct this type of analysis, in silicotesting comes in handy. In our study, to identify sites in the network that need to be blocked to have an inhibitory effect on atherosclerosis in hyperglycemia, which is toxic for the human organism, we created a model using Petri net theory and performed analyses. We have found that blocking isoforms of protein kinase C (PKC)-PKCβ and PKCγ-in diabetic patients can contribute to the inhibition of atherosclerosis progression. In addition, we have discovered that aldose reductase inhibition can slow down atherosclerosis progression, and this has been shown to reduce PKC (β and γ) expression in DM. It has also been observed that diminishing oxidative stress through the inhibitory effect on the AGE-RAGE axis may be a promising therapeutic approach in treating hyperglycemia-induced atherosclerosis. Moreover, the blockade of NADPH oxidase, the key enzyme responsible for the formation of reactive oxygen species (ROS) in blood vessels, only moderately slowed down atherosclerosis development. However, unlike aldose reductase blockade, or direct PKC (β and γ), the increased production of mitochondrial ROS associated with mitochondrial dysfunction effectively stopped after NADPH oxidase blockade. The results obtained may constitute the basis for further in-depth research.

Hypotheses on Atherogenesis Triggering: Does the Infectious Nature of Atherosclerosis Development Have a Substruction?

Since the end of the 20th century, it has been clear that atherosclerosis is an inflammatory disease. However, the main triggering mechanism of the inflammatory process in the vascular walls is still unclear. To date, many different hypotheses have been put forward to explain the causes of atherogenesis, and all of them are supported by strong evidence. Among the main causes of atherosclerosis, which underlies these hypotheses, the following can be mentioned: lipoprotein modification, oxidative transformation, shear stress, endothelial dysfunction, free radicals' action, homocysteinemia, diabetes mellitus, and decreased nitric oxide level. One of the latest hypotheses concerns the infectious nature of atherogenesis. The currently available data indicate that pathogen-associated molecular patterns from bacteria or viruses may be an etiological factor in atherosclerosis. This paper is devoted to the analysis of existing hypotheses for atherogenesis triggering, and special attention is paid to the contribution of bacterial and viral infections to the pathogenesis of atherosclerosis and cardiovascular disease.

Sex-specific differences in atherosclerosis, thrombospondin-1, and smooth muscle cell differentiation in metabolic syndrome versus non-metabolic syndrome mice

Introduction

Metabolic syndrome (MetS) amplifies the risks of atherosclerosis. Despite well-known sexual dimorphism in atherosclerosis, underlying mechanisms are poorly understood. Our previous findings highlight a proatherogenic protein, thrombospondin-1 (TSP-1), in hyperglycemia- or hyperleptinemia (mimicking obesity)-induced atherosclerosis. However, the role of TSP-1 in the development of atherosclerosis prompted by co-existing hyperglycemia and obesity, characteristic of MetS, is unknown. The goal of this study was to examine sex-specific differences in lesion progression in a model of combined MetS and atherosclerosis (KKAyApoE) and interrogate how these differences relate to TSP-1 expression.

Methods

Male and female KKAy^+/-ApoE^-/- (with ectopic agouti gene expression) and age-matched non-agouti KKAy^-/-ApoE^-/- littermates were placed on a standard laboratory diet from 4 to 24 weeks age followed by blood and tissue harvests for biochemical, molecular, and aortic root morphometric studies.

Results

Metabolic profiling confirmed MetS phenotype of KKAy^+/-ApoE^-/-; however, only male genotypes were glucose intolerant with elevated VLDL-cholesterol and VLDL-triglyceride levels. Aortic root morphometry demonstrated profound lipid-filled lesions, increased plaque area, and augmented inflammatory and SMC abundance in MetS vs non-MetS males. This increase in lesion burden was accompanied with elevated TSP-1 and attenuated LMOD-1 (SM contractile marker) and SRF (transcriptional activator of SM differentiation) expression in male MetS aortic vessels. In contrast, while lipid burden, plaque area, and TSP-1 expression increased in MetS and non-MetS female mice, there was no significant difference between these genotypes. Increased collagen content was noted in MetS and non-MetS genotypes, specific to female mice. Measurement of plasma testosterone revealed a link between the atherogenic phenotype and abnormally high or low testosterone levels. To interrogate whether TSP-1 plays a direct role in SMC de-differentiation in MetS, we generated KKAy^+/- mice with and without global TSP-1 deletion. Immunoblotting showed increased SM contractile markers in male KKAy^+/-TSP-1^-/- aortic vessels vs male KKAy^+/-TSP-1^{+/ +}. In contrast, TSP-1 deletion had no effect on SM contractile marker expression in female genotypes.

Conclusion

Together, the current study implicates a role of plasma testosterone in sex-specific differences in atherosclerosis and TSP-1 expression in MetS vs non-MetS mice. Our data suggest a sex-dependent differential role of TSP-1 on SMC de-differentiation in MetS. Collectively, these findings underscore a fundamental link between TSP-1 and VSMC phenotypic transformation in MetS.

Dynamics of Gut Microbiota and Clinical Variables after Ketogenic and Mediterranean Diets in Drug-Naïve Patients with Type 2 Diabetes Mellitus and Obesity

Type 2 diabetes mellitus (T2DM), the most common form of diabetes, is a progressive chronic metabolic disease that has increasingly spread worldwide, enhancing the mortality rate, particularly from cardiovascular diseases (CVD). Lifestyle improvement through diet and physical activity is, together with drug treatment, the cornerstone of T2DM management. The Mediterranean diet (MD), which favors a prevalence of unprocessed vegetable foods and a reduction in red meats and industrial foods, without excluding any food category, is usually recommended. Recently, scientific societies have promoted a very low-calorie ketogenic diet (VLCKD), a multiphasic protocol that limits carbohydrates and then gradually re-introduces them, with a favorable outcome on body weight and metabolic parameters. Indeed, gut microbiota (GM) modifications have been linked to overweight/obesity and metabolic alterations typical of T2DM. Diet is known to affect GM largely, but only a few studies have investigated the effects of VLCKD on GM, especially in T2DM. In this study, we have compared anthropometric, biochemical, lifestyle parameters, the quality of life, and the GM of eleven patients with recently diagnosed T2DM and overweight or obesity, randomly assigned to two groups of six and five patients who followed the VLCKD (KETO) or hypocaloric MD (MEDI) respectively; parameters were recorded at baseline (T0) and after two (T2) and three months (T3). The results showed that VLCKD had more significant beneficial effects than MD on anthropometric parameters, while biochemical improvements did not statistically differ. As for the GM, despite the lack of significant results regarding the alpha and beta diversity, and the Firmicutes/Bacteroidota ratio between the two groups, in the KETO group, a significant increase in beneficial microbial taxa such as Verrucomicrobiota phylum with its members Verrucomicrobiae, Verrucomicrobiales, Akkermansiaceae, and Akkermansia, Christensenellaceae family, Eubacterium spp., and a reduction in microbial taxa previously associated with obesity (Firmicutes and Actinobacteriota) or other diseases (Alistipes) was observed both at T2 and T3. With regards to the MEDI group, variations were limited to a significant increase in Actinobacteroidota phylum at T2 and T3 and Firmicutes phylum at T3. Moreover, a metagenomic alteration linked to some metabolic pathways was found exclusively in the KETO group. In conclusion, both dietary approaches allowed patients to improve their state of health, but VLCKD has shown better results on body composition as well as on GM profile.

Probiotics Bring New Hope for Atherosclerosis Prevention and Treatment

Cardiovascular disease is the leading cause of human mortality and morbidity worldwide. Atherosclerosis (AS) is the underlying pathological responsible in most acute and severe cardiovascular diseases including myocardial infarction and stroke. However, current drugs applied to the treatment of AS are not clinically effective, and there is a large residual risk of cardiovascular disease and multiple side effects. Increasing evidence supports a close relationship between microorganisms and the incidence of AS. Recent data have shown that probiotics can improve multiple key factors involved in the development and progression of AS, including cholesterol metabolism imbalance, endothelial dysfunction, proinflammatory factor production, macrophage polarization, intestinal flora disturbance, and infection with pathogenic microorganisms, and therefore probiotics have attracted great interest as a novel potential “medicine”. This review is aimed at summarizing the effects of probiotics on various influencing factors, and providing valuable insights in the search for early prevention and potential therapeutic strategies for AS.

Dicarbonyl-Dependent Modification of LDL as a Key Factor of Endothelial Dysfunction and Atherosclerotic Vascular Wall Damage

The review presents evidence that the main damage to the vascular wall occurs not from the action of “oxidized” LDL, which contain hydroperoxy acyls in the phospholipids located in their outer layer, but from the action of LDL particles whose apoprotein B-100 is chemically modified with low molecular weight dicarbonyls, such as malondialdehyde, glyoxal, and methylglyoxal. It has been argued that dicarbonyl-modified LDL, which have the highest cholesterol content, are particularly “atherogenic”. High levels of dicarbonyl-modified LDL have been found to be characteristic of some mutations of apoprotein B-100. Based on the reviewed data, we hypothesized a common molecular mechanism underlying vascular wall damage in atherosclerosis and diabetes mellitus. The important role of oxidatively modified LDL in endothelial dysfunction is discussed in detail. In particular, the role of the interaction of the endothelial receptor LOX-1 with oxidatively modified LDL, which leads to the expression of NADPH oxidase, which in turn generates superoxide anion radical, is discussed. Such hyperproduction of ROS can cause destruction of the glycocalyx, a protective layer of endotheliocytes, and stimulation of apoptosis in these cells. On the whole, the accumulated evidence suggests that carbonyl modification of apoprotein B-100 of LDL is a key factor responsible for vascular wall damage leading to atherogenesis and endothelial dysfunction. Possible ways of pharmacological correction of free radical processes in atherogenesis and diabetogenesis are also discussed.

The Remnant Lipoprotein Hypothesis of Diabetes-Associated Cardiovascular Disease

Both type 1 and type 2 diabetes are associated with an increased risk of atherosclerotic cardiovascular disease (CVD). Research based on human-first or bedside-to-bench approaches has provided new insights into likely mechanisms behind this increased risk. Although both forms of diabetes are associated with hyperglycemia, it is becoming increasingly clear that altered lipoprotein metabolism also plays a critical role in predicting CVD risk in people with diabetes. This review examines recent findings indicating that increased levels of circulating remnant lipoproteins could be a missing link between diabetes and CVD. Although CVD risk associated with diabetes is clearly multifactorial in nature, these findings suggest that we should increase efforts in evaluating whether remnant lipoproteins or the proteins that govern their metabolism are biomarkers of incident CVD in people living with diabetes and whether reducing remnant lipoproteins will prevent the increased CVD risk associated with diabetes.

Metabolism in atherosclerotic plaques: immunoregulatory mechanisms in the arterial wall

Over the last decade, there has been a growing interest to understand the link between metabolism and the immune response in the context of metabolic diseases but also beyond, giving then birth to a new field of research. Termed 'immunometabolism', this interdisciplinary field explores paradigms of both immunology and metabolism to provided unique insights into different disease pathogenic processes, and the identification of new potential therapeutic targets. Similar to other inflammatory conditions, the atherosclerotic inflammatory process in the artery has been associated with a local dysregulated metabolic response. Thus, recent studies show that metabolites are more than just fuels in their metabolic pathways, and they can act as modulators of vascular inflammation and atherosclerosis. In this review article, we describe the most common immunometabolic pathways characterised in innate and adaptive immune cells, and discuss how macrophages' and T cells' metabolism may influence phenotypic changes in the plaque. Moreover, we discuss the potential of targeting immunometabolism to prevent and treat cardiovascular diseases (CVDs).

The Significance of Systemic Immune-Inflammatory Index for Mortality Prediction in Diabetic Patients Treated with Off-Pump Coronary Artery Bypass Surgery

Diabetes mellitus (DM) represents a complex carbohydrate metabolism disorder characterized by inflammatory over-reactivity. The study aimed to investigate the potential influence of postoperative inflammatory activation on mortality risk after off-pump coronary artery bypass grafting in diabetic patients. There were 510 patients treated with off-pump coronary artery bypass grafting due to stable complex coronary artery disease, including 175 patients with type-2 DM (T2DM.) The mean follow-up time was 3.7 +/− 1.5 years with a 9% all-cause mortality rate in the diabetic group. In multivariable analysis, preoperative comorbidities (stroke, peripheral artery disease, postoperative systemic inflammatory index >952, and postoperative left ventricle ejection fraction (LVEF) < 45%) were revealed as prognostic factors. The receiver operator characteristics curve analysis for postoperative calculations of systemic immune-inflammatory index (SII) appeared significant (AUC = 0.698, p = 0.008), yielding sensitivity of 68.75% and specificity of 71.07%. Systemic immune-inflammatory index (SII) can be regarded as a predictive marker for long-term prognosis in diabetic patients after off-pump coronary artery bypass grafting. The role of perioperative inflammatory activation may play a crucial role in mortality prediction.

Insulin Prevents Hypercholesterolemia by Suppressing 12a-Hydroxylated Bile Acid Production

Background: The risk of cardiovascular disease in type 1 diabetes remains extremely high, despite marked advances in blood glucose control and even the widespread use of cholesterol synthesis inhibitors. Thus, a deeper understanding of insulin regulation of cholesterol metabolism, and its disruption in type 1 diabetes, could reveal better treatment strategies. Methods: To define the mechanisms by which insulin controls plasma cholesterol levels, we knocked down the insulin receptor, FoxO1, and the key bile acid synthesis enzyme, CYP8B1. We measured bile acid composition, cholesterol absorption, and plasma cholesterol. In parallel, we measured markers of cholesterol absorption and synthesis in humans with type 1 diabetes treated with ezetimibe and statins in a double-blind crossover study. Results: Mice with hepatic deletion of the insulin receptor showed marked increases in 12α-hydroxylated bile acids (12HBAs), cholesterol absorption, and plasma cholesterol. This phenotype was entirely reversed by hepatic deletion of FoxO1. FoxO1 is inhibited by insulin, and required for the production of 12HBAs, which promote intestinal cholesterol absorption and suppress hepatic cholesterol synthesis. Knockdown of Cyp8b1 normalized 12HBA levels and completely prevented hypercholesterolemia in mice with hepatic deletion of the insulin receptor (n=5-30) as well as mouse models of type 1 diabetes (n=5-22). In parallel, the cholesterol absorption inhibitor, ezetimibe, normalized cholesterol absorption and LDL-cholesterol in patients with type 1 diabetes as well as, or better than, the cholesterol synthesis inhibitor, simvastatin (n=20). Conclusions: Insulin, by inhibiting FoxO1 in the liver, reduces 12HBAs, cholesterol absorption, and plasma cholesterol levels. Thus, type 1 diabetes leads to a unique set of derangements in cholesterol metabolism, with increased absorption rather than synthesis. These derangements are reversed by ezetimibe, but not statins, which are currently the first line of lipid-lowering treatment in type 1 diabetes. Taken together, these data suggest that a personalized approach to lipid lowering in type 1 diabetes may be more effective and highlight the need for further studies specifically in this group of patients.

AHR Signaling Interacting with Nutritional Factors Regulating the Expression of Markers in Vascular Inflammation and Atherogenesis

There is strong evidence that exposure to fine particulate matter (PM_2.5) and a high-fat diet (HFD) increase the risk of mortality from atherosclerotic cardiovascular diseases. Recent studies indicate that PM_2.5 generated by combustion activates the Aryl Hydrocarbon Receptor (AHR) and inflammatory cytokines contributing to PM_2.5-mediated atherogenesis. Here we investigate the effects of components of a HFD on PM-mediated activation of AHR in macrophages. Cells were treated with components of a HFD and AHR-activating PM and the expression of biomarkers of vascular inflammation was analyzed. The results show that glucose and triglyceride increase AHR-activity and PM_2.5-mediated induction of cytochrome P450 (CYP)1A1 mRNA in macrophages. Cholesterol, fructose, and palmitic acid increased the PM- and AHR-mediated induction of proinflammatory cytokines in macrophages. Treatment with palmitic acid significantly increased the expression of inflammatory cytokines and markers of vascular injury in human aortic endothelial cells (HAEC) after treatment with PM_2.5. The PM_2.5-mediated activation of the atherogenic markers C-reactive protein (CRP) and S100A9, a damage-associated molecular pattern molecule, was found to be AHR-dependent and involved protein kinase A (PKA) and a CCAAT/enhancer-binding protein (C/EBP) binding element. This study identified nutritional factors interacting with AHR signaling and contributing to PM_2.5-induced markers of atherogenesis and future cardiovascular risk.

Serum uric acid is independently associated with aortic arch calcification in a cross-sectional study of middle-aged and elderly women

BACKGROUND AND AIMS

The increased serum uric acid (SUA) level is associated with the prevalence of cardiovascular disease (CVD) risks. Aortic arch calcification (AAC) reflects subclinical coronary atherosclerosis and is linked to subsequent cardiovascular morbidity and mortality risks closely. To better understand the role of SUA on arteriosclerosis and CVD, we aim to determine the association between SUA and the presence of AAC.

METHODS AND RESULTS

A total of 5920 individuals aged >45 years old without prior CVD disease were included. The prevalence rate of AAC was 14.4% in all participants and a significantly increasing trend for AAC prevalence rate was found across the SUA tertiles (p < 0.001 for trend). Subsequent subgroup analyses revealed that this positive association trend was only significant in female subjects. After adjusting for confounders, SUA is an independent predictor for the presence of AAC in overall participants and in women.

CONCLUSION

SUA is independently associated with AAC in middle-aged and elderly population, especially in the women. More research needs to determine whether lower thresholds for CVD risk screening for those middle-aged and elderly women with higher SUA tertile even without hyperuricemia are warranted.

The Diabetes Mellitus-Atherosclerosis Connection: The Role of Lipid and Glucose Metabolism and Chronic Inflammation

Diabetes mellitus comprises a group of carbohydrate metabolism disorders that share a common main feature of chronic hyperglycemia that results from defects of insulin secretion, insulin action, or both. Insulin is an important anabolic hormone, and its deficiency leads to various metabolic abnormalities in proteins, lipids, and carbohydrates. Atherosclerosis develops as a result of a multistep process ultimately leading to cardiovascular disease associated with high morbidity and mortality. Alteration of lipid metabolism is a risk factor and characteristic feature of atherosclerosis. Possible links between the two chronic disorders depending on altered metabolic pathways have been investigated in numerous studies. It was shown that both types of diabetes mellitus can actually induce atherosclerosis development or further accelerate its progression. Elevated glucose level, dyslipidemia, and other metabolic alterations that accompany the disease development are tightly involved in the pathogenesis of atherosclerosis at almost every step of the atherogenic process. Chronic inflammation is currently considered as one of the key factors in atherosclerosis development and is present starting from the earliest stages of the pathology initiation. It may also be regarded as one of the possible links between atherosclerosis and diabetes mellitus. However, the data available so far do not allow for developing effective anti-inflammatory therapeutic strategies that would stop atherosclerotic lesion progression or induce lesion reduction. In this review, we summarize the main aspects of diabetes mellitus that possibly affect the atherogenic process and its relationship with chronic inflammation. We also discuss the established pathophysiological features that link atherosclerosis and diabetes mellitus, such as oxidative stress, altered protein kinase signaling, and the role of certain miRNA and epigenetic modifications.

Monocytes and Macrophages as Protagonists in Vascular Complications of Diabetes

With the increasing prevalence of diabetes worldwide, vascular complications of diabetes are also on the rise. Diabetes results in an increased risk of macrovascular complications, with atherosclerotic cardiovascular disease (CVD) being the leading cause of death in adults with diabetes. The exact mechanisms for how diabetes promotes CVD risk are still unclear, although it is evident that monocytes and macrophages are key players in all stages of atherosclerosis both in the absence and presence of diabetes, and that phenotypes of these cells are altered by the diabetic environment. Evidence suggests that at least five pro-atherogenic mechanisms involving monocytes and macrophages contribute to the accelerated atherosclerotic lesion progression and hampered lesion regression associated with diabetes. These changes include (1) increased monocyte recruitment to lesions; (2) increased inflammatory activation; (3) altered macrophage lipid accumulation and metabolism; (4) increased macrophage cell death; and (5) reduced efferocytosis. Monocyte and macrophage phenotypes and mechanisms have been revealed mostly by different animal models of diabetes. The roles of specific changes in monocytes and macrophages in humans with diabetes remain largely unknown. There is an ongoing debate on whether the changes in monocytes and macrophages are caused by altered glucose levels, insulin deficiency or insulin resistance, lipid abnormalities, or combinations of these factors. Current research in humans and mouse models suggests that reduced clearance of triglyceride-rich lipoproteins and their remnants is one important mechanism whereby diabetes adversely affects macrophages and promotes atherosclerosis and CVD risk. Although monocytes and macrophages readily respond to the diabetic environment and can be seen as protagonists in diabetes-accelerated atherosclerosis, they are likely not instigators of the increased CVD risk.

Increased apolipoprotein C3 drives cardiovascular risk in type 1 diabetes

Type 1 diabetes mellitus (T1DM) increases the risk of atherosclerotic cardiovascular disease (CVD) in humans by poorly understood mechanisms. Using mouse models of T1DM-accelerated atherosclerosis, we found that relative insulin deficiency rather than hyperglycemia elevated levels of apolipoprotein C3 (APOC3), an apolipoprotein that prevents clearance of triglyceride-rich lipoproteins (TRLs) and their remnants. We then showed that serum APOC3 levels predict incident CVD events in subjects with T1DM in the Coronary Artery Calcification in Type 1 Diabetes (CACTI) study. To explore underlying mechanisms, we investigated the impact of Apoc3 antisense oligonucleotides (ASOs) on lipoprotein metabolism and atherosclerosis in a mouse model of T1DM. Apoc3 ASO treatment abolished the increased hepatic Apoc3 expression in diabetic mice - resulting in lower levels of TRLs - without improving glycemic control. APOC3 suppression also prevented arterial accumulation of APOC3-containing lipoprotein particles, macrophage foam cell formation, and the accelerated atherosclerosis in diabetic mice. Our observations demonstrate that relative insulin deficiency increases APOC3 and that this results in elevated levels of TRLs and accelerated atherosclerosis in a mouse model of T1DM. Because serum levels of APOC3 predicted incident CVD events in the CACTI study, inhibiting APOC3 might reduce CVD risk in T1DM patients.

Effects of dapagliflozin vs vildagliptin on cardiometabolic parameters in diabetic patients with coronary artery disease: a randomised study

AIMS

Sodium glucose co-transporter-2 inhibitors have been shown to reduce cardiovascular events and heart failure in type 2 diabetic (T2D) patients with high cardiovascular risk. Dipeptidyl peptidase-4 inhibitors showed neutral effects and may increase risk of heart failure. We aimed to compare cardiometabolic effects of dapagliflozin and vildagliptin in T2D patients with coronary artery disease (CAD).

METHODS

Forty-nine T2D patients with CAD were randomly assigned to dapagliflozin (n = 25) or vildagliptin (n = 24) for 6 months in a double-blind fashion. Cardiometabolic parameters were collected at baseline and at the end of treatments.

RESULTS

Mean age was 63.2 ± 7.9 years (female 46.9%). Baseline characteristics did not differ between two groups. At 6 months, HbA_1C significantly decreased in both dapaglifozin and vildagliptin groups (0.6 ± 1.0% vs 0.8 ± 1.4%, P = 0.22, respectively). There was no difference between the changes in lipid profiles. Body mass index decreased in patients receiving dapagliflozin, whereas it increased in those receiving vildagliptin (-1.27 [95% confidence interval -2.01, -0.53] vs 1.72 [0.72, 2.72] kg, P < 0.001). The reduction in systolic blood pressure and high-sensitivity troponin T was observed in the dapagliflozin group (-9.87 [-18.00, -1.15] mmHg and 2.49 [-4.50, -0.47] pg/mL) but not in vildagliptin group (-1.97 [-9.42, 5.48] mmHg and 1.98 [-0.02, 3.97] pg/mL). The mean haemoglobin increased in the dapagliflozin group, whereas the mean platelet volume increased in the vildagliptin group. There was no significant change in the inflammatory markers in both the groups.

CONCLUSIONS

The extraglycaemic effects of dapagliflozin and vildagliptin on cardiometabolic parameters in T2D with CAD were different. The more favourable effects of dapagliflozin compared to vildagliptin may have explained the cardiovascular benefits observed only in sodium glucose co-transporter-2 inhibitors.

Gold nanoparticles reduce high glucose-induced oxidative-nitrosative stress regulated inflammation and apoptosis via tuberin-mTOR/NF-κB pathways in macrophages

Hyperglycemia is a risk factor for cardiovascular mortality and morbidity, and directly responsible for exacerbating macrophage activation and atherosclerosis. We showed that gold nanoparticles (AuNPs) reduce the high glucose (HG)-induced atherosclerosis-related complications in macrophages via oxidative-nitrosative stress-regulated inflammation and apoptosis. The effects of AuNPs on oxidative-nitrosative stress markers such as cellular antioxidants were attenuated by HG exposure, leading to reduction in the accumulation of reactive oxygen/nitrogen species in cellular compartments. Further, these abnormalities of antioxidants level and reactive oxygen/nitrogen species accumulations initiate cellular stress, resulting in the activation of nuclear factor κB (NF-κB) via ERK1/2mitogen-activated protein kinase (MAPK)/Akt/tuberin-mammalian target of rapamycin (mTOR) pathways. The activated NF-κB stimulates inflammatory mediators, which subsequently subdue biomolecules damage, leading to aggravation of the inflammatory infiltration and immune responses. Treatment of AuNPs inhibits the intracellular redox-sensitive signaling pathways, inflammation, and apoptosis in macrophages. Together, our results indicate that AuNPs may modulate HG-induced oxidative-nitrosative stress. These effects may be sealed tight due to the fact that AuNPs treatment reduces the activation of NF-κB by ERK1/2MAPK/Akt/tuberin-mTOR pathways-mediated inflammatory genes expression and cellular stress responses, which may be beneficial for minimizing the atherosclerosis.