Role of AGEs in the progression and regression of atherosclerotic plaques

Network pharmacology, molecular docking, and in vitro experimental verification of the mechanism of Guanxining in treating diabetic atherosclerosis

ETHNOPHARMACOLOGICAL RELEVANCE

Guanxinning(GXN) tablet is a patented traditional Chinese medicine widely used to prevent and treat cardiovascular diseases. However, its potential mechanism and target in anti-diabetic atherosclerosis have not been clarified.

AIM

The aim of this study was to investigate the underlying targets and mechanisms of action GXN in the treatment of diabetic atherosclerosis, employing a combination of network pharmacology, molecular docking, and in vitro experimental verification.

METHODS

We predicted the core components and targets of GXN in the treatment of diabetic atherosclerosis through various databases, and made analysis and molecular docking. In vitro, we induced injury in human umbilical vein endothelial cells using glucose/palmitate and observed the effects of GXN on cellular damage high-glucose and high-fat conditions, subsequently elucidating its molecular mechanisms.

RESULTS

A total of 14 active components and 157 targets of GXN were identified. Using the PPI network, we selected 9 core active components and 20 targets of GXN. GO functional analysis revealed that these targets were primarily associated with apoptosis signaling pathways in response to endoplasmic reticulum stress and reactive oxygen species responses. Molecular docking confirmed the strong binding affinities of the primary active components of GXN with ERN1, MAPK1 and BECN1. In vitro experiments demonstrated the ability of GXN to restore endothelial cell activity, enhance cell migration and inhibit sICAM secretion, and upregulate the expression of endoplasmic reticulum stress-related proteins (IRE1, XBP1) and autophagy-related proteins (Beclin1, LC3A, and LC3B), while simultaneously inhibiting endothelial cell apoptosis under high-glucose and high-fat conditions.

CONCLUSIONS

Our findings suggest that GXN can potentially safeguard endothelial cells from the adverse effects of high-glucose and high-fat by modulating the interactions between endoplasmic reticulum stress and autophagy. Therefore, GXN is a promising candidate for the prevention and treatment of diabetic atherosclerosis.

AGEs promote atherosclerosis by increasing LDL transcytosis across endothelial cells via RAGE/NF-κB/Caveolin-1 pathway

OBJECTIVE

To elucidate the mechanism whereby advanced glycation end products (AGEs) accelerate atherosclerosis (AS) and to explore novel therapeutic strategies for atherosclerotic cardiovascular disease.

METHODS AND RESULTS

The effect of AGEs on low-density lipoprotein (LDL) transcytosis across endothelial cells (ECs) was assessed using an in vitro model of LDL transcytosis. We observed that AGEs activated the receptor for advanced glycation end products (RAGE) on the surface of ECs and consequently upregulated Caveolin-1, which in turn increased caveolae-mediated LDL transcytosis and accelerated AS progression. Our molecular assessment revealed that AGEs activate the RAGE-NF-κB signaling, which then recruits the NF-κB subunit p65 to the RAGE promoter and consequently enhances RAGE transcription, thereby forming a positive feedback loop between the NF-κB signaling and RAGE expression. Increased NF-κB signaling ultimately upregulated Caveolin-1, promoting LDL transcytosis, and inhibition of RAGE suppressed AGE-induced LDL transcytosis. In ApoE-/- mice on a high-fat diet, atherosclerotic plaque formation was accelerated by AGEs but suppressed by EC-specific knockdown of RAGE.

CONCLUSION

AGEs accelerate the development of diabetes-related AS by increasing the LDL transcytosis in ECs through the activation of the RAGE/NF-κB/Caveolin-1 axis, which may be targeted to prevent or treat diabetic macrovascular complications.

Network-pharmacology-based research on protective effects and underlying mechanism of Shuxin decoction against myocardial ischemia/reperfusion injury with diabetes

BACKGROUND

Patients with diabetes mellitus are at higher risk of myocardial ischemia/ reperfusion injury (MI/RI). Shuxin decoction (SXT) is a proven recipe modi-fication from the classic herbal formula "Wu-tou-chi-shi-zhi-wan" according to the traditional Chinese medicine theory. It has been successfully used to alleviate secondary MI/RI in patients with diabetes mellitus in the clinical setting. However, the underlying mechanism is still unclear.

AIM

To further determine the mechanism of SXT in attenuating MI/RI associated with diabetes.

METHODS

This paper presents an ensemble model combining network pharmacology and biology. The Traditional Chinese Medicine System Pharmacology Database was accessed to select key components and potential targets of the SXT. In parallel, therapeutic targets associated with MI/RI in patients with diabetes were screened from various databases including Gene Expression Omnibus, DisGeNet, Genecards, Drugbank, OMIM, and PharmGKB. The potential targets of SXT and the therapeutic targets related to MI/RI in patients with diabetes were intersected and subjected to bioinformatics analysis using the Database for Annotation, Visualization and Integrated Discovery. The major results of bioinformatics analysis were subsequently validated by animal experiments.

RESULTS

According to the hypothesis derived from bioinformatics analysis, SXT could possibly ameliorate lipid metabolism disorders and exert anti-apoptotic effects in MI/RI associated with diabetes by reducing oxidized low density lipoprotein (LDL) and inhibiting the advanced glycation end products (AGE)-receptor for AGE (RAGE) signaling pathway. Subsequent animal experiments confirmed the hypothesis. The treatment with a dose of SXT (2.8 g/kg/d) resulted in a reduction in oxidized LDL, AGEs, and RAGE, and regulated the level of blood lipids. Besides, the expression of apoptosis-related proteins such as Bax and cleaved caspase 3 was down-regulated, whereas Bcl-2 expression was up-regulated. The findings indicated that SXT could inhibit myocardial apoptosis and improve cardiac function in MI/RI in diabetic rats.

CONCLUSION

This study indicated the active components and underlying molecular therapeutic mechanisms of SXT in MI/RI with diabetes. Moreover, animal experiments verified that SXT could regulate the level of blood lipids, alleviate cardiomyocyte apoptosis, and improve cardiac function through the AGE-RAGE signaling pathway.

Advanced glycation end products are associated with cardiovascular risk in the Mexican population

BACKGROUND AND AIMS

Chronic exposure to hyperglycemia is a significant risk factor for cardiovascular disease (CVD). Advanced glycation end products (AGES) result from multiple sugar-dependent reactions interacting with proteins and their receptors, generating endothelial dysfunction and CVD. However, there is little epidemiological data about its impact on CVD risk. We aimed to assess the association between circulating AGES and CVD risk in the Mexican population.

METHODS AND RESULTS

We used longitudinal data from waves 2004-2006 and 2010-2012 of 1195 participants from the Health Workers Cohort Study. Circulating AGES were assessed by radioimmunoassay, and cardiovascular risk (CVR) was computed with the Framingham risk score. Linear and logistic fixed-effects regression models were used to assess the interest association, adjusting for confounding factors. An increase in 200 μU/ml of AGES was associated with a 0.18% increased risk of CVD (95% CI 0.05-0.31%). After adjusting for physical activity and smoking status, individuals who increased their AGES category had higher odds of middle-high CVR (low to medium AGES: OR 1.83, 95% CI 1.11-3.20; low to high AGES: OR 2.61, 95% CI 1.51-4.50). The associations remained statistically significant when we further adjusted for insulin resistance, dietary intake of AGES, and total daily calorie intake.

CONCLUSION

Our data show that circulating AGES are associated with the Framingham CVD risk score, independently of other major risk factors for CVD in the Mexican population.

SMTP-44D Inhibits Atherosclerotic Plaque Formation in Apolipoprotein-E Null Mice Partly by Suppressing the AGEs-RAGE Axis

SMTP-44D has been reported to have anti-oxidative and anti-inflammatory reactions, including reduced expression of receptor for advanced glycation end products (RAGE) in experimental diabetic neuropathy. Although activation of RAGE with its ligands, and advanced glycation end products (AGEs), play a crucial role in atherosclerotic cardiovascular disease, a leading cause of death in diabetic patients, it remains unclear whether SMTP-44D could inhibit experimental atherosclerosis by suppressing the AGEs–RAGE axis. In this study, we investigated the effects of SMTP-44D on atherosclerotic plaque formation and expression of AGEs in apolipoprotein-E null (Apoe−/−) mice. We further studied here whether and how SMTP-44D inhibited foam cell formation of macrophages isolated from Apoe−/− mice ex vivo. Although administration of SMTP-44D to Apoe−/− mice did not affect clinical or biochemical parameters, it significantly decreased the surface area of atherosclerotic lesions and reduced the atheromatous plaque size, macrophage infiltration, and AGEs accumulation in the aortic roots. SMTP-44D bound to immobilized RAGE and subsequently attenuated the interaction of AGEs with RAGE in vitro. Furthermore, foam cell formation evaluated by Dil-oxidized low-density lipoprotein (ox-LDL) uptake, and gene expression of RAGE, cyclin-dependent kinase 5 (Cdk5) and CD36 in macrophages isolated from SMTP-44D-treated Apoe−/− mice were significantly decreased compared with those from saline-treated mice. Gene expression levels of RAGE and Cdk5 were highly correlated with each other, the latter of which was also positively associated with that of CD36. The present study suggests that SMTP-44D may inhibit atherosclerotic plaque formation in Apoe−/− mice partly by blocking the AGEs-RAGE-induced ox-LDL uptake into macrophages via the suppression of Cdk5-CD36 pathway.

Nε-(carboxymethyl)lysine promotes lipid uptake of macrophage via cluster of differentiation 36 and receptor for advanced glycation end products

BACKGROUND

Advanced glycation end products (AGEs) are diabetic metabolic toxic products that cannot be ignored. N^ε-(carboxymethyl)lysine (CML), a component of AGEs, could increase macrophage lipid uptake, promote foam cell formation, and thereby accelerate atherosclerosis. The receptor for AGEs (RAGE) and cluster of differentiation 36 (CD36) were the receptors of CML. However, it is still unknown whether RAGE and CD36 play key roles in CML-promoted lipid uptake.

AIM

Our study aimed to explore the role of RAGE and CD36 in CML-induced mac-rophage lipid uptake.

METHODS

In this study, we examined the effect of CML on lipid uptake by Raw264.7 macrophages. After adding 10 mmol/L CML, the lipid accumulation in macro-phages was confirmed by oil red O staining. Expression changes of CD36 and RAGE were detected with immunoblotting and quantitative real-time polymerase chain reaction. The interaction between CML with CD36 and RAGE was verified by immunoprecipitation. We synthesized a novel N-succinimidyl-4-¹⁸F-fluorobenzoate-CML radioactive probe. Radioactive receptor-ligand binding assays were performed to test the binding affinity between CML with CD36 and RAGE. The effects of blocking CD36 or RAGE on CML-promoting lipid uptake were also detected.

RESULTS

The study revealed that CML significantly promoted lipid uptake by macro-phages. Immunoprecipitation and radioactive receptor-ligand binding assays indicated that CML could specifically bind to both CD36 and RAGE. CML had a higher affinity for CD36 than RAGE. ARG82, ASN71, and THR70 were the potential interacting amino acids that CD36 binds to CML Anti-CD36 and anti-RAGE could block the uptake of CML by macrophages. The lipid uptake promotion effect of CML was significantly attenuated after blocking CD36 or RAGE.

CONCLUSION

Our results suggest that the binding of CML with CD36 and RAGE promotes macrophage lipid uptake.

Dietary Nε-(carboxymethyl) lysine affects cardiac glucose metabolism and myocardial remodeling in mice

BACKGROUND

Myocardial remodeling is a key factor in the progression of cardiovascular disease to the end stage. In addition to myocardial infarction or stress overload, dietary factors have recently been considered associated with myocardial remodeling. N^ε-(carboxymethyl)lysine (CML) is a representative foodborne toxic product, which can be ingested via daily diet. Therefore, there is a marked need to explore the effects of dietary CML on the myocardium.

AIM

To explore the effects of dietary CML (dCML) on the heart.

METHODS

C57 BL/6 mice were divided into a control group and a dCML group. The control group and the dCML group were respectively fed a normal diet or diet supplemented with CML for 20 wk. Body weight and blood glucose were recorded every 4 wk. ¹⁸F-fluorodeoxyglucose (FDG) was used to trace the glucose uptake in mouse myocardium, followed by visualizing with micro-positron emission tomography (PET). Myocardial remodeling and glucose metabolism were also detected. In vitro, H9C2 cardiomyocytes were added to exogenous CML and cultured for 24 h. The effects of exogenous CML on glucose metabolism, collagen I expression, hypertrophy, and apoptosis of cardiomyocytes were analyzed.

RESULTS

Our results suggest that the levels of fasting blood glucose, fasting insulin, and serum CML were significantly increased after 20 wk of dCML. Micro-PET showed that ¹⁸F-FDG accumulated more in the myocardium of the dCML group than in the control group. Histological staining revealed that dCML could lead to myocardial fibrosis and hypertrophy. The indexes of myocardial fibrosis, apoptosis, and hypertrophy were also increased in the dCML group, whereas the activities of glucose metabolism-related pathways and citrate synthase (CS) were significantly inhibited. In cardiomyocytes, collagen I expression and cellular size were significantly increased after the addition of exogenous CML. CML significantly promoted cellular hypertrophy and apoptosis, while pathways involved in glucose metabolism and level of Cs mRNA were significantly inhibited.

CONCLUSION

This study reveals that dCML alters myocardial glucose metabolism and promotes myocardial remodeling.

The Correlation between the Level of Skin Advanced Glycation End Products in Type 2 Diabetes Mellitus and the Stages of Diabetic Retinopathy and the Types of Traditional Chinese Medicine Syndrome

Objective

We aimed to analyze the correlation between the level of skin advanced glycation end products (AGEs) in type 2 diabetes mellitus (T2DM) patients and the diabetic retinopathy (DR) staging in different traditional Chinese medicine (TCM) syndromes.

Methods

416 T2DM patients were divided into normal group, nonproliferative diabetic retinopathy (NPDR) group (mild, moderate, and severe), and proliferative diabetic retinopathy (PDR) group according to the DR grade. Patients' height, weight, fasting blood glucose (FBG), hemoglobin A1C (HbA1c), blood lipid, renal function, and skin AGEs were measured. According to TCM syndrome differentiation criteria, 230 patients with T2DM and DR were divided into I. qi and yin deficiency, collateral stasis group; II. liver and kidney deficiency, eye collaterals loss group; and III. yin and yang deficiency, blood stasis, and phlegm coagulation group.

Results

The skin AGEs levels of different DR staging groups were statistically significant (P < 0.05), and the skin AGEs levels in the mild and moderate NPDR groups were significantly higher (P < 0.05) than those of the normal group. It was significantly higher (P < 0.05) in the severe NPDR group than in the normal group, mild and moderate NPDR groups. The skin AGEs levels of the PDR group were significantly higher (P < 0.05) than the normal group, mild and moderate NPDR groups. It was positively correlated with DR stage, HbA1c, total cholesterol (TC), low-density lipoprotein (LDL), and urine metal analysis (UMA) (r = 0.467, 0.411, 0.413, 0.503, 0.424, P < 0.05). The skin AGEs levels of the qi and yin deficiency and collaterals stasis syndrome group were significantly higher (P < 0.05) than in the liver and kidney deficiency and eye collaterals loss groups. It was also significantly higher (P < 0.05) in yin and yang deficiency, blood stasis, and phlegm coagulation syndrome groups than in qi and yin deficiency and collaterals stasis syndrome groups.

Conclusion

There is a positive correlation between skin AGEs and DR staging in T2DM patients. Skin AGEs level is predictive for the risk of DR complications in T2DM patients and is vital in assessing DR degree per TCM syndrome type.

Inflammatory Mechanisms of Diabetes and Its Vascular Complications

The main cause of death in patients with type 2 DM is cardiovascular complications resulting from the progression of atherosclerosis. The pathophysiology of the association between diabetes and its vascular complications is complex and multifactorial and closely related to the toxic effects of hyperglycemia that causes increased generation of reactive oxygen species and promotes the secretion of pro-inflammatory cytokines. Subsequent oxidative stress and inflammation are major factors of the progression of type 2 DM and its vascular complications. Data on the pathogenesis of the development of type 2 DM and associated cardiovascular diseases, in particular atherosclerosis, open up broad prospects for the further development of new diagnostic and therapeutic approaches.

Advanced Glycation End Products: key player of the pathogenesis of atherosclerosis

Atherosclerosis is the most common type of cardiovascular disease, and it causes intima thickening, plaque development, and ultimate blockage of the artery lumen. Advanced glycation end products (AGEs) are thought to have a role in the development and progression of atherosclerosis. there is developing an enthusiasm for AGEs as a potential remedial target. AGES mainly induce arterial damage and exacerbate the development of atherosclerotic plaques by triggering cell receptor-dependent signalling. The interplay of AGEs with RAGE, a transmembrane signalling receptor present across all cells important to atherosclerosis, changes cell activity, boosts expression of genes, and increases the outflow of inflammatory compounds, resulting in arterial wall injury and plaque formation. Here in this review, function of AGEs in the genesis, progression, and instability of atherosclerosis is discussed. In endothelial and smooth muscle cells, as well as platelets, the interaction of AGEs with their transmembrane cell receptor, RAGE, triggers intracellular signalling, resulting in endothelial damage, vascular smooth muscle cell function modification, and changed platelet activity.

Targeting the cytoskeleton and extracellular matrix in cardiovascular disease drug discovery

INTRODUCTION

Currently, cardiovascular disease (CVD) drug discovery has focused primarily on addressing the inflammation and immunopathology aspects inherent to various CVD phenotypes such as cardiac fibrosis and coronary artery disease. However, recent findings suggest new biological pathways for cytoskeletal and extracellular matrix (ECM) regulation across diverse CVDs, such as the roles of matricellular proteins (e.g. tenascin-C) in regulating the cellular microenvironment. The success of anti-inflammatory drugs like colchicine, which targets microtubule polymerization, further suggests that the cardiac cytoskeleton and ECM provide prospective therapeutic opportunities.

AREAS COVERED

Potential therapeutic targets include proteins such as gelsolin and calponin 2, which play pivotal roles in plaque development. This review focuses on the dynamic role that the cytoskeleton and ECM play in CVD pathophysiology, highlighting how novel target discovery in cytoskeletal and ECM-related genes may enable therapeutics development to alter the regulation of cellular architecture in plaque formation and rupture, cardiac contractility, and other molecular mechanisms.

EXPERT OPINION

Further research into the cardiac cytoskeleton and its associated ECM proteins is an area ripe for novel target discovery. Furthermore, the structural connection between the cytoskeleton and the ECM provides an opportunity to evaluate both entities as sources of potential therapeutic targets for CVDs.

Role of advanced glycation end products on vascular smooth muscle cells under diabetic atherosclerosis

Atherosclerosis (AS) is a chronic inflammatory disease and leading cause of cardiovascular diseases. The progression of AS is a multi-step process leading to high morbidity and mortality. Hyperglycemia, dyslipidemia, advanced glycation end products (AGEs), inflammation and insulin resistance which strictly involved in diabetes are closely related to the pathogenesis of AS. A growing number of studies have linked AGEs to AS. As one of the risk factors of cardiac metabolic diseases, dysfunction of VSMCs plays an important role in AS pathogenesis. AGEs are increased in diabetes, participate in the occurrence and progression of AS through multiple molecular mechanisms of vascular cell injury. As the main functional cells of vascular, vascular smooth muscle cells (VSMCs) play different roles in each stage of atherosclerotic lesions. The interaction between AGEs and receptor for AGEs (RAGE) accelerates AS by affecting the proliferation and migration of VSMCs. In addition, increasing researches have reported that AGEs promote osteogenic transformation and macrophage-like transformation of VSMCs, and affect the progression of AS through other aspects such as autophagy and cell cycle. In this review, we summarize the effect of AGEs on VSMCs in atherosclerotic plaque development and progression. We also discuss the AGEs that link AS and diabetes mellitus, including oxidative stress, inflammation, RAGE ligands, small noncoding RNAs.

Dyslipidemia, Diabetes and Atherosclerosis: Role of Inflammation and ROS-Redox-Sensitive Factors

The prevalence of diabetes is growing at an alarming rate with increased disability, morbidity, and often premature mortality because of the various complications of this disorder. Chronic hyperglycemia, dyslipidemia, and other metabolic alterations lead to the development and progression of macro- and microvascular complications of diabetes including cardiovascular, retinal and kidney disease. Despite advances in glucose and lipid lowering treatments, a large number of diabetic individuals develop one or more types of these complications, ultimately leading to end-organ damage over the time. Atherosclerosis is the major macro-vascular complications of diabetes and the primary underlying cause of cardiovascular disease (CVD) posing heavy burden on the health care system. In this review, we discuss the involvement of dyslipidemia in the progression of atherosclerosis by activating the pro-inflammatory cytokines and oxidative stress-related factors. In addition, we also provide information on various pharmacological agents that provides protection against diabetic atherosclerosis by reducing inflammation and oxidative stress.

Comparison of metabolic fate, target organs, and microbiota interactions of free and bound dietary advanced glycation end products

Increased intake of Western diets and ultra-processed foods is accompanied by increased intake of advanced glycation end products (AGEs). AGEs can be generated exogenously in the thermal processing of food and endogenously in the human body, which associated with various chronic diseases. In food, AGEs can be divided into free and bound forms, which differ in their bioavailability, digestion, absorption, gut microbial interactions and untargeted metabolites. We summarized the measurements and contents of free and bound AGE in foods. Moreover, the ingestion, digestion, absorption, excretion, gut microbiota interactions, and metabolites and metabolic pathways between free and bound AGEs based on animal and human studies were compared. Bound AGEs were predominant in most of the selected foods, while beer and soy sauce were rich in free AGEs. Only 10%-30% of AGEs were absorbed into the systemic circulation when orally administered. The excretion of ingested free and bound AGEs was approximately 90% and 60%, respectively. Dietary free CML has a detrimental effect on gut microbiota composition, while bound AGEs have both detrimental and beneficial impacts. Free and bound dietary AGEs changed amino acid metabolism, energy metabolism and carbohydrate metabolism. And besides, bound dietary AGEs altered vitamin metabolism, and glycerolipid metabolism.

Effects of a 12-Month Treatment with Glucagon-like Peptide-1 Receptor Agonists, Sodium-Glucose Cotransporter-2 Inhibitors, and Their Combination on Oxidant and Antioxidant Biomarkers in Patients with Type 2 Diabetes

Imbalance between oxidative stress burden and antioxidant capacity is implicated in the course of atherosclerosis among type 2 diabetic patients. We addressed the effects of insulin, glucagon-like peptide-1 receptor agonists (GLP1-RA), sodium-glucose cotransporter-2 inhibitors (SGLT-2i), and their combination on levels of oxidant and antioxidant biomarkers. We recruited a total of 160 type 2 diabetics, who received insulin (n = 40), liraglutide (n = 40), empagliflozin (n = 40), or their combination (GLP-1RA+SGLT-2i) (n = 40). We measured at baseline, at 4 and at 12 months of treatment: (a) Thiobarbituric Acid Reactive Substances (TBARS), (b) Malondialdehyde (MDA), (c) Reducing Power (RP), (d) 2,2¢-azino-bis-(3-ethylbenzthiazoline-6-sulphonic acid) radical (ABTS) and (e) Total Antioxidant Capacity TAC). Dual treatment resulted in significant improvement of TBARS, MDA, and ABTS at four months compared with the other groups (p < 0.05 for all comparisons). At twelve months, all participants improved TBARS, MDA, and ABTS (p < 0.05). At 12 months, GLP1-RA and GLP-1RA+SGLT2-i provided a greater reduction of TBARS (−8.76% and −9.83%) compared with insulin or SGLT2i (−0.5% and 3.22%), (p < 0.05). GLP1-RA and GLP-1RA+SGLT-2i showed a greater reduction of MDA (−30.15% and −31.44%) compared with insulin or SGLT2i (4.72% and −3.74%), (p < 0.05). SGLT2i and GLP-1RA+SGLT2-i showed increase of ABTS (12.87% and 14.13%) compared with insulin or GLP1-RA (2.44% and −3.44%), (p < 0.05). Only combined treatment resulted in increase of TAC compared with the other groups after 12 months of treatment (p < 0.05).12-month treatment with GLP1-RA and SGLT2i resulted in reduction of biomarkers responsible for oxidative modifications and increase of antioxidant biomarker, respectively. The combination treatment was superior and additive to each separate agent and also the beneficial effects appeared earlier.

Glucose-Dependent Insulinotropic Polypeptide Suppresses Foam Cell Formation of Macrophages through Inhibition of the Cyclin-Dependent Kinase 5-CD36 Pathway

Glucose-dependent insulinotropic polypeptide (GIP) has been reported to have an atheroprotective property in animal models. However, the effect of GIP on macrophage foam cell formation, a crucial step of atherosclerosis, remains largely unknown. We investigated the effects of GIP on foam cell formation of, and CD36 expression in, macrophages extracted from GIP receptor-deficient (Gipr^−/−) and Gipr^+/+ mice and cultured human U937 macrophages by using an agonist for GIP receptor, [D-Ala²]GIP(1–42). Foam cell formation evaluated by esterification of free cholesterol to cholesteryl ester and CD36 gene expression in macrophages isolated from Gipr^+/+ mice infused subcutaneously with [D-Ala²]GIP(1–42) were significantly suppressed compared with vehicle-treated mice, while these beneficial effects were not observed in macrophages isolated from Gipr^−/− mice infused with [D-Ala²]GIP(1–42). When macrophages were isolated from Gipr^+/+ and Gipr^−/− mice, and then exposed to [D-Ala²]GIP(1–42), similar results were obtained. [D-Ala²]GIP(1–42) attenuated ox-LDL uptake of, and CD36 gene expression in, human U937 macrophages as well. Gene expression level of cyclin-dependent kinase 5 (Cdk5) was also suppressed by [D-Ala²]GIP(1–42) in U937 cells, which was corelated with that of CD36. A selective inhibitor of Cdk5, (R)-DRF053 mimicked the effects of [D-Ala²]GIP(1–42) in U937 cells. The present study suggests that GIP could inhibit foam cell formation of macrophages by suppressing the Cdk5-CD36 pathway via GIP receptor.

Macrophage Plasticity and Atherosclerosis Therapy

Atherosclerosis is a chronic disease starting with the entry of monocytes into the subendothelium and the subsequent differentiation into macrophages. Macrophages are the major immune cells in atherosclerotic plaques and are involved in the dynamic progression of atherosclerotic plaques. The biological properties of atherosclerotic plaque macrophages determine lesion size, composition, and stability. The heterogenicity and plasticity of atherosclerotic macrophages have been a hotspot in recent years. Studies demonstrated that lipids, cytokines, chemokines, and other molecules in the atherosclerotic plaque microenvironment regulate macrophage phenotype, contributing to the switch of macrophages toward a pro- or anti-atherosclerosis state. Of note, M1/M2 classification is oversimplified and only represent two extreme states of macrophages. Moreover, M2 macrophages in atherosclerosis are not always protective. Understanding the phenotypic diversity and functions of macrophages can disclose their roles in atherosclerotic plaques. Given that lipid-lowering therapy cannot completely retard the progression of atherosclerosis, macrophages with high heterogeneity and plasticity raise the hope for atherosclerosis regression. This review will focus on the macrophage phenotypic diversity, its role in the progression of the dynamic atherosclerotic plaque, and finally discuss the possibility of treating atherosclerosis by targeting macrophage microenvironment.

AGEs accumulation is related to muscle degeneration and vascular calcification in peritoneal dialysis patients

BACKGROUND

Patients with chronic kidney disease (CKD) are affected by dynapenia, sarcopenia, and vascular calcification. Advanced glycation end products (AGEs) may accumulate in peritoneal dialysis (PD) patients and favor sarcopenia via changes in collagen cross-linking, muscle protein breakdown, and the calcification of arterial smooth muscle cells via p38-MAPK activation. The aim of this study is to explore the relationships between AGEs, muscle degeneration, and coronary artery calcification.

METHODS

This was a clinical observational study in patients with CKD undergoing PD, in which serum and skin AGEs (AGEs-sAF), cumulative glucose load, muscle strength and functional tests, muscle ultrasounds with elastography, coronary artery calcium (CAC) quantification, and muscle density by multislice computed tomography were measured.

RESULTS

27 patients aged 48±16 years, dialysis vintage of 27±17 months, had AGEs-sAF levels of 3.09±0.65 AU (elevated in 13 [87%] patients), grip strength levels of 26.2±9.2 kg (11 [42%] patients with dynapenia), gait speed of 1.04±0.3 m/s (abnormal in 14 [58%] patients) and "timed-up-and-go test" (TUG) of 10.5±2.2s (abnormal in 7 [26%] patients). Correlations between AGEs-sAF levels and femoral rectus elastography (R=-0.74; p=0.02), anterior-tibialis elastography (R= -0.68; p=0.04) and CAC (R=0.64; p=0.04) were detected. Cumulative glucose load correlated with femoral rectal elastography (R=-0.6; p=0.02), and serum glycated hemoglobin concentrations correlated with psoas muscle density (R= -0.58; p=0.04) and CAC correlated with psoas muscle density (R=0.57; p=0.01) and lumbar square muscle density (R=-0.63; p=0.005).

CONCLUSIONS

The study revealed associations between AGEs accumulation and lower muscle stiffness/density. Associations that linked muscle degeneration parameters with vascular calcification were observed.

Circulating miRNA in atherosclerosis: a clinical biomarker and early diagnostic tool

Atherosclerosis, which is a vascular disease, is characterized by narrowing the arteries and forming plaque inside arteries. There is a record 17.5 million associated deaths recorded annually, representing 31% of global death. It has been noted that there is an association between vascular fibrosis and atherosclerosis. The thickening of the arterial wall and reduction of the lumen diameter may cause unwarranted deposition of extracellular matrix (ECM), and these conditions help in the progression of many clinical diseases and pathological conditions such as atherosclerosis. Here, we reviewed the involvement of various circulating microRNAs (miRNAs) in the very early diagnosis of atherosclerosis. We have also tried to provide an insight into the advantages and validation of circulating miRNAs through different techniques. We have discussed different circulating miRNAs, such as miR-17, miR-17-5p, miR-29b, miR-30, miR-92a, miR-126, miR-143, miR-145, miR-146a, miR-212, miR-218, miR-221, miR-222, miR-361-5p, as a biomarker for clinical diagnosis of atherosclerosis. The insightful demonstration in this review will offer a better opportunity for the researchers and technology developers in understanding the current scenario of circulating miRNA, which could facilitate them in improving the current diagnostic technologies of atherosclerosis in clinics.

Conditioned Media of Choroid Plexus Epithelium Cells Attenuates High Pi-Induced Calcification of MOVAS Cells by Inhibiting ROS-Mediated Signal Pathways

Vascular calcification was an independent risk of cardiovascular and cerebrovascular diseases (CCDs). Studies reported that conditioned media of choroid plexus epithelium cells (CPECs-CM) showed potential neuroprotective effects. However, the protective effect of CPECs-CM against vascular calcification (VC) has not been reported yet. Herein, high phosphate (HPi)–induced calcification model in mouse aortic vascular smooth muscle cells (MOVAS) was established, and the protective effects and underlying mechanism of CPECs-CM against HPi-induced calcification were explored. The results indicated that CPEC cells were successfully isolated and cultured, and CPECs-CM co-treatment significantly inhibited HPi-induced calcification of MOVAS cells through blocking alkaline phosphatase activity and expression. CPECs-CM co-treatment also suppressed reactive oxide species–mediated DNA damage in HPi-treated MOVAS cells. Moreover, dysfunction of MAPKs and PI3K/AKT pathways both contributed to HPi-induced calcification of MOVAS cells, and CPECs-CM co-treatment attenuated HPi-induced calcification by normalizing MAPKs and PI3K/AKT expression. Taken together, our findings provide evidence that CPECs-CM had the potential to inhibit vascular calcification with potent application in chemoprevention and chemotherapy of human CCD.

Apolipoprotein E Gene Polymorphism, Glycated Hemoglobin, and Peripheral Arterial Disease Risk in Chinese Type 2 Diabetic Patients

Background

The apolipoprotein E (ApoE) gene polymorphism has been found to influence plasma lipid concentration, and its correlation with peripheral arterial disease (PAD) has been investigated. However, it is unclear whether ApoE is associated with PAD in Chinese type 2 diabetes mellitus (T2DM) patients. Therefore, our study is aimed at investigating the relationship between the ApoE gene polymorphism and PAD in Chinese T2DM patients.

Methods

A total of 192 T2DM patients were divided into two groups: T2DM and T2DM with PAD. The clinical and biochemical parameters were obtained. Polymerase chain reaction was used to identify the genotypes of ApoE. The multivariable logistic regression analysis was used to identify the possible risk factor for PAD.

Results

There were no significant differences in the genotype and allele frequencies of ApoE between the T2DM and T2DM with PAD groups. However, the T2DM with PAD group tended to have more ε4/ε4/

Conclusions

These results demonstrated that there was no evidence of a relationship between ApoE and PAD.

Oxidative Stress and Inflammation in Renal and Cardiovascular Complications of Diabetes

Simple Summary

The progressive nature of type 2 diabetes mellitus (T2DM) leads to micro- and macro-vascular complications, including renal and cardiovascular disease. These alone, or in combination, are a major cause of premature morbidity and mortality in diabetic patients. Despite advances in glucose lowering treatments, these diabetic complications are still inadequately prevented or reversed. This ongoing cardiovascular–renal burden in diabetes poses a heavy cost on the health care system. Therefore, there is an urgent need to develop more effective treatments. In this review, we discuss how oxidative stress and inflammation induce and perpetuate the renal and cardiovascular complications of diabetes. It is particularly important to understand these driving mechanisms in order to elucidate pharmacological targets and mechanism-based future drug therapies.

Abstract

Oxidative stress and inflammation are considered major drivers in the pathogenesis of diabetic complications, including renal and cardiovascular disease. A symbiotic relationship also appears to exist between oxidative stress and inflammation. Several emerging therapies target these crucial pathways, to alleviate the burden of the aforementioned diseases. Oxidative stress refers to an imbalance between reactive oxygen species (ROS) and antioxidant defenses, a pathological state which not only leads to direct cellular damage but also an inflammatory cascade that further perpetuates tissue injury. Emerging therapeutic strategies tackle these pathways in a variety of ways, from increasing antioxidant defenses (antioxidants and Nrf2 activators) to reducing ROS production (NADPH oxidase inhibitors and XO inhibitors) or inhibiting the associated inflammatory pathways (NLRP3 inflammasome inhibitors, lipoxins, GLP-1 receptor agonists, and AT-1 receptor antagonists). This review summarizes the mechanisms by which oxidative stress and inflammation contribute to and perpetuate diabetes associated renal and cardiovascular disease along with the therapeutic strategies which target these pathways to provide reno and cardiovascular protection in the setting of diabetes.

Vitamin D Deficiency May Not Be an Independent Risk Factor for Peripheral Arterial Disease in Middle-Aged and Elderly Patients with Type 2 Diabetes in China

Background

Vitamin D deficiency can lead to the increased severity and prevalence of metabolic disorders. However, the relationship between levels of 25-hydroxyvitamin D (25(OH)D) and peripheral arterial disease (PAD) is controversial. Therefore, the purpose of our study was to explore the relationship between 25(OH)D levels and PAD in middle-aged and elderly type 2 diabetes mellitus (T2DM) patients in China.

Methods

In this study, a total of 183 patients with T2DM were enrolled and categorized into groups with or without PAD. Clinical and biochemical parameters were assessed, and a Pearson analysis was used to identify a possible association between levels of 25(OH)D and glycated hemoglobin (HbA1c). Some biochemical parameters were also assessed in the T2DM patients with PAD according to vitamin D status. Interactions were also explored among HbA1c control, 25(OH)D levels, and PAD. The possible risk factors for PAD were measured by multivariable logistic regression analyses.

Results

Firstly, the parameters including age, HbA1c, and disease duration between T2DM and T2DM+PAD groups showed significantly different. In addition, the frequency of smoking in the group of T2DM patients was significantly less than that in the T2DM patients with the PAD group, while the frequency of well-controlled HbA1c in the patients with T2DM was significantly higher. There is a trend that the levels of 25(OH)D and HbA1c are correlated, but no interactions among vitamin D deficiency, HbA1c control, and PAD were found. However, HbA1c significantly differed between groups with vitamin D deficiency and insufficiency in the T2DM patients with PAD. According to the multivariate logistic regression analyses, the PAD risk factors of T2DM patients were family history of diabetes, smoking, age, disease duration, HbA1c, and LDL.

Conclusions

The findings demonstrate that the deficiency of vitamin D level is not related to PAD, but HbA1c may be linked to the presence of PAD in middle-aged and elderly patients with T2DM in China.

AGE-RAGE Axis Stimulates Oxidized LDL Uptake into Macrophages through Cyclin-Dependent Kinase 5-CD36 Pathway via Oxidative Stress Generation

Advanced glycation end products (AGEs) are localized in macrophage-derived foam cells within atherosclerotic lesions, which could be associated with the increased risk of atherosclerotic cardiovascular disease under diabetic conditions. Although foam cell formation of macrophages has been shown to be enhanced by AGEs, the underlying molecular mechanism remains unclear. Since cyclin-dependent kinase 5 (Cdk5) is reported to modulate inflammatory responses in macrophages, we investigated whether Cdk5 could be involved in AGE-induced CD36 gene expression and foam cell formation of macrophages. AGEs significantly increased Dil-oxidized low-density lipoprotein (ox-LDL) uptake, and Cdk5 and CD36 gene expression in U937 human macrophages, all of which were inhibited by DNA aptamer raised against RAGE (RAGE-aptamer). Cdk5 and CD36 gene expression levels were correlated with each other. An antioxidant, N-acetyl-l-cysteine, mimicked the effects of RAGE-aptamer on AGE-exposed U937 cells. A selective inhibitor of Cdk5, (R)-DRF053, attenuated the AGE-induced Dil-ox-LDL uptake and CD36 gene expression, whereas anti-CD36 antibody inhibited the Dil-ox-LDL uptake but not Cdk5 gene expression. The present study suggests that AGEs may stimulate ox-LDL uptake into macrophages through the Cdk5–CD36 pathway via RAGE-mediated oxidative stress.

Advanced glycation end products enhance macrophage polarization to the M1 phenotype via the HIF-1α/PDK4 pathway

Atherosclerotic plaque rupture followed by luminal thrombosis is recognized as the main cause of acute cardiovascular events, especially in patients with diabetes. Although previous studies identified stimulation of macrophages polarization with advanced glycation end products (AGEs) results in the rapid progression of atherosclerosis, the underlying mechanisms are not understood fully. The purpose of this study was to investigate the effect of hypoxia-inducible factor-1α (HIF-1α) and pyruvate dehydrogenase kinase 4 (PDK4), critical proteins for regulating glucose metabolism, on macrophages polarization in diabetic atherosclerosis, and relevant mechanisms involved. We found that there is an increased number of M1 macrophages in carotid atherosclerotic tissues of diabetic mice and in AGE-bovine serum albumin (BSA)-treated RAW264.7 cells. Furthermore, we observed that HIF-1α was upregulated in AGE-BSA-induced M1 polarization and that the HIF-1α knockdown reduced macrophage polarization to M1 phenotype caused by AGE-BSA via regulation of PDK4. Thus, our study identified the critical role of HIF-1α/PDK4 axis in AGE-BSA-induced M1 polarization, which reflected the potential association between energy metabolism and inflammation in macrophages.

Role of Matrix Vesicles in Bone-Vascular Cross-Talk

Matrix mineralization can be divided into physiological mineralization and pathological mineralization. There is a consensus among existing studies that matrix vesicles (MVs) are the starting sites of bone mineralization, and each component of MVs serves a certain function in mineralization. In addition, ectopic MVs pathologically promote undesired calcification, the primary focus of which is the promotion of vascular calcification. However, the specific mechanisms of the actions of MVs in bone-vascular axis cross-talk have not been fully elucidated. This review summarizes the latest research in this field and explores the roles of MVs in the bone-vascular axis with the aim of generating new ideas for the prevention and treatment of vascular calcification and bone metabolic disease.

Butanolic Extract of Noni Inhibits Proliferation, Inflammation, and Proprotein Convertase Subtilisin Kexin Type 9 (PCSK9) Expression in Cultured Smooth Muscle Cells

Platelet-derived growth factor-BB (PDGF-BB) plays a central role in smooth muscle cell (SMC) proliferation and inflammation, being involved in atherosclerotic cardiovascular disease. We have previously found that butanolic extract of noni, a tropical plant belonging to the family Rubiaceae, exerts anti-inflammatory effects on endothelial cells exposed to advanced glycation end products (AGEs). Here, we examined the effects of noni extract on oxidative stress production, growth, and inflammatory reactions in PDGF-BB or AGE-exposed SMCs. Reactive oxygen species (ROS) generation, cell proliferation, and adhesion were measured by a fluorescent dye, a colorimetric agent, and labeled THP-1 cells, respectively. Gene and protein expression was evaluated by real-time reverse transcription-polymerase chain reaction and Western blot analysis. Butanolic extract of noni reduced ROS production, monocyte chemoattractant protein-1, intercellular adhesion molecule-1, and proprotein convertase subtilisin kexin type 9 (PCSK9) expression, and proliferation in, and THP-1 cell adhesion to, PDGF-BB-exposed SMCs. Gene expression and protein level of receptor for AGEs (RAGE) were significantly decreased by noni extract in SMCs. Furthermore, AGEs significantly increased PCSK9 mRNA and protein levels in SMCs, which were inhibited by noni extract or an antioxidant N-acetylcysteine. Our present study suggests that butanolic extract of noni not only inhibits the PDGF-BB-induced proliferation and inflammatory reactions in SMCs through its antioxidative properties but also reduces PCSK9 levels in AGE-exposed SMCs via suppression of RAGE expression. Butanolic extract of noni may play a protective role against atherosclerosis.

Risk of coronary heart disease in the rural population in Xinjiang: A nested case-control study in China

Background and aim

Coronary heart disease (CHD) is a chronic complex disease caused by a combination of factors such as lifestyle behaviors and environmental and genetic factors. We conducted this study to evaluate the risk factors affecting the development of CHD in Xinjiang, and to obtain valuable information for formulating appropriate local public health policies.

Method

We conducted a nested case-control study with 277 confirmed CHD cases and 554 matched controls. The association of the risk factors with the risk of CHD was assessed using the multivariate Cox proportional hazard model. Multiplicative interactions were evaluated by entering interaction terms in the Cox proportional hazard model. The additive interactions among the risk factors were assessed by the index of additive interaction.

Results

The risk of CHD increased with frequent high-fat food consumption, dyslipidemia, obesity, and family history of CHD after adjustment for drinking, smoking status, hypertension, diabetes, family history of hypertension, and family history of diabetes. We noted consistent interactions between family history of CHD and frequent high-fat food consumption, family history of CHD and obesity, frequent high-fat food consumption and obesity, frequent high-fat food consumption and dyslipidemia, and obesity and dyslipidemia. The risk of CHD events increased with the presence of the aforementioned interactions.

Conclusions

Frequent high-fat food consumption, family history of CHD, dyslipidemia and obesity were independent risk factors for CHD, and their interactions are important for public health interventions in patients with CHD in Xinjiang.

Role of Sortilin and Matrix Vesicles in Nε-Carboxymethyl-Lysine-Induced Diabetic Atherosclerotic Calcification

BACKGROUND AND AIMS

To investigate the role of Sortilin and matrix vesicles (MVs) in Nε-Carboxymethyl-lysine (CML)-induced diabetic atherosclerotic calcification (AC).

METHODS

At human level, the correlation between Sortilin and CD9 (marker proteins of MVs) in serum MVs and CML in serum was explored by enzyme-linked immunosorbent assay (ELISA) detection and Pearson correlation analysis. After a diabetic apoE^-/- mouse model was constructed, the calcification of aorta and the expressions of related proteins under CML and MVs injection were observed by calcification staining, immunofluorescence staining, and Western blot. MVs levels released by smooth muscle cells (SMCs) under different treatments was detected by nanometer tracking analysis (NTA). After treating SMCs with MVs and Anti-Sortilin, cell calcification was observed by Alizarin red staining.

RESULTS

Serological analysis of patients showed that the concentrations of Sortilin and CD9 in serum MVs were positively correlated with the concentration of CML in serum. Animal experiments showed that CML could promote the progression of diabetic AC and the high expression of Sortilin in plaques. Diabetic apoE^-/- mouse tail vein injection of CML-induced SMCs-derived MVs obviously aggravated AC. Cell experiment results showed that a high concentration of CML significantly promoted the release of MVs from SMCs. MVs from this source could markedly worsen cell calcification, while the administration of GW4869 (a widely used extracellular vesicles biogenesis inhibitor) significantly reduced cell calcification. Finally, treatment of high concentrations of CML could also promote the recruitment of Sortilin to MVs, and administration of Anti-Sortilin could markedly reduce cell calcification caused by MVs.

CONCLUSION

We proved that CML not only affects the release of MVs from SMCs but also affects the recruitment of Sortilin to MVs, thereby promoting diabetic AC. This discovery may provide a new strategy for targeted prevention of vascular calcification in diabetes.