Molecular mechanisms linking diabetes to the accelerated development of atherosclerosis

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.

Advancements in the Treatment of Atherosclerosis: From Conventional Therapies to Cutting-Edge Innovations

Atherosclerosis is a leading cause of morbidity and mortality worldwide, driven by a complex interplay of lipid dysregulation, inflammation, and vascular pathology. Despite advancements in understanding the multifactorial nature of atherosclerosis and improvements in clinical management, existing therapies often fall short in reversing the disease, focusing instead on symptom alleviation and risk reduction. This review highlights recent strides in identifying genetic markers, elucidating inflammatory pathways, and understanding environmental contributors to atherosclerosis. It also evaluates the efficacy and limitations of current pharmacological treatments, revascularization techniques, and the impact of these interventions on patient outcomes. Furthermore, we explore innovative therapeutic strategies, including the promising fields of nanomedicine, nucleic acid-based therapies, and immunomodulation, which offer potential for targeted and effective treatment modalities. However, integrating these advances into clinical practice is challenged by regulatory, economic, and logistical barriers. This review synthesizes the latest research and clinical advancements to provide a comprehensive roadmap for future therapeutic strategies and emphasize the critical need for innovative approaches to fundamentally change the course of atherosclerosis management.

Endothelial KLF11 is a novel protector against diabetic atherosclerosis

BACKGROUND

Atherosclerotic cardiovascular diseases remain the leading cause of mortality in diabetic patients, with endothelial cell (EC) dysfunction serving as the initiating step of atherosclerosis, which is exacerbated in diabetes. Krüppel-like factor 11 (KLF11), known for its missense mutations leading to the development of diabetes in humans, has also been identified as a novel protector of vascular homeostasis. However, its role in diabetic atherosclerosis remains unexplored.

METHODS

Diabetic atherosclerosis was induced in both EC-specific KLF11 transgenic and knockout mice in the Ldlr-/- background by feeding a diabetogenic diet with cholesterol (DDC). Single-cell RNA sequencing (scRNA-seq) was utilized to profile EC dysfunction in diabetic atherosclerosis. Additionally, gain- and loss-of-function experiments were conducted to investigate the role of KLF11 in hyperglycemia-induced endothelial cell dysfunction.

RESULTS

We found that endothelial KLF11 deficiency significantly accelerates atherogenesis under diabetic conditions, whereas KLF11 overexpression remarkably inhibits it. scRNA-seq profiling demonstrates that loss of KLF11 increases endothelial-to-mesenchymal transition (EndMT) during atherogenesis under diabetic conditions. Utilizing gain- and loss-of-function approaches, our in vitro study reveals that KLF11 significantly inhibits EC inflammatory activation and TXNIP-induced EC oxidative stress, as well as Notch1/Snail-mediated EndMT under high glucose exposure.

CONCLUSION

Our study demonstrates that endothelial KLF11 is an endogenous protective factor against diabetic atherosclerosis. These findings indicate that manipulating KLF11 could be a promising approach for developing novel therapies for diabetes-related cardiovascular complications.

Overexpression of miR-199b-5p in Colony Forming Unit-Hill's Colonies Positively Mediates the Inflammatory Response in Subclinical Cardiovascular Disease Model: Metformin Therapy Attenuates Its Expression

Well-controlled type 1 diabetes (T1DM) is characterized by inflammation and endothelial dysfunction, thus constituting a suitable model of subclinical cardiovascular disease (CVD). miR-199b-5p overexpression in murine CVD has shown proatherosclerotic effects. We hypothesized that miR-199b-5p would be overexpressed in subclinical CVD yet downregulated following metformin therapy. Inflammatory and vascular markers were measured in 29 individuals with T1DM and 20 matched healthy controls (HCs). miR-199b-5p expression in CFU-Hill's colonies was analyzed from each study group, and correlations with inflammatory/vascular health indices were evaluated. Significant upregulation of miR-199b-5p was observed in T1DM, which was significantly downregulated by metformin. miR-199b-5p correlated positively with vascular endothelial growth factor-D and c-reactive protein (CRP: nonsignificant). ROC analysis determined miR-199b-5p to define subclinical CVD by discriminating between HCs and T1DM individuals. ROC analyses of HbA1c and CRP showed that the upregulation of miR-199b-5p in T1DM individuals defined subclinical CVD at HbA1c > 44.25 mmol and CRP > 4.35 × 106 pg/mL. Ingenuity pathway analysis predicted miR-199b-5p to inhibit the target genes SIRT1, ETS1, and JAG1. Metformin was predicted to downregulate miR-199b-5p via NFATC2 and STAT3 and reverse its downstream effects. This study validated the antiangiogenic properties of miR-199b-5p and substantiated miR-199b-5p overexpression as a biomarker of subclinical CVD. The downregulation of miR-199b-5p by metformin confirmed its cardio-protective effect.

Resistance Training in Cardiovascular Diseases: A Review on Its Effectiveness in Controlling Risk Factors

Cardiovascular Disease (CVD), a term encompassing various disorders affecting the heart and blood vessels, includes coronary artery disease (CAD). CAD is primarily due to the development of atherosclerotic plaques that disrupt blood flow, oxygenation, and nutrient delivery to the myocardium. Risk factors contributing to CAD progression include smoking, hypertension, diabetes mellitus (DM), dyslipidaemia, and obesity. While aerobic exercise (AE) has shown promising results in controlling CVD risk factors, the impact of resistance training (RT) has not been extensively investigated. This review aims to describe the effects of RT on CVD risk factors based on studies retrieved from PubMed and Google Scholar databases. Both isometric and isotonic RT have been found to decrease systolic blood pressure (SBP), diastolic blood pressure, or mean arterial pressure, with SBP showing a more significant reduction. Hypertensive patients engaging in RT alongside a calorie-restricted diet demonstrated significant improvements in blood pressure. RT is associated with increased nitric oxide bioavailability, sympathetic modulation, and enhanced endothelial function. In type-2 DM patients, 8-12 weeks of RT led to improvements in fasting blood glucose levels, insulin secretion, metabolic syndrome risk, and glucose transporter numbers. Combining AE with RT had a more significant impact in reducing insulin resistance and enhancing blood glucose compared to performing exercises separately. It also significantly decreased total cholesterol, triglycerides, and low-density lipoprotein levels while increasing high-density lipoprotein within 12 weeks of application. However, improvements are considered insignificant when lipid levels are already low to normal at baseline. The administration of RT resulted in weight loss and improved body mass index, with more pronounced effects seen when combining AE with RT and a calorie-restricted diet. Considering these results, the administration of RT, either alone or in combination with AE, proves beneficial in rehabilitating CAD patients by improving various risk factors.

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.

N6-methyladenosine RNA methylation in diabetic kidney disease

Diabetic kidney disease (DKD) is a major microvascular complication of diabetes, and hyperglycemic memory associated with diabetes carries the risk of disease occurrence, even after the termination of blood glucose injury. The existence of hyperglycemic memory supports the concept of an epigenetic mechanism involving n6-methyladenosine (m6A) modification. Several studies have shown that m6A plays a key role in the pathogenesis of DKD. This review addresses the role and mechanism of m6A RNA modification in the progression of DKD, including the regulatory role of m6A modification in pathological processes, such as inflammation, oxidative stress, fibrosis, and non-coding (nc) RNA. This reveals the importance of m6A in the occurrence and development of DKD, suggesting that m6A may play a role in hyperglycemic memory phenomenon. This review also discusses how some gray areas, such as m6A modified multiple enzymes, interact to affect the development of DKD and provides countermeasures. In conclusion, this review enhances our understanding of DKD from the perspective of m6A modifications and provides new targets for future therapeutic strategies. In addition, the insights discussed here support the existence of hyperglycemic memory effects in DKD, which may have far-reaching implications for the development of novel treatments. We hypothesize that m6A RNA modification, as a key factor regulating the development of DKD, provides a new perspective for the in-depth exploration of DKD and provides a novel option for the clinical management of patients with DKD.

Association of Cardiac Valve Calcification and 1-year Mortality after Lower-extremity Amputation in Diabetic Patients: A Retrospective Study

BACKGROUND

Cardiac valve calcification predisposes patients to a higher risk of adverse cardiovascular events. This study aimed to investigate the association between cardiac valve calcification and 1-year mortality in diabetic patients after lower-extremity amputation.

METHODS

This was a retrospective study conducted on the clinical data of diabetic patients who underwent lower-extremity amputation admitted to the Sun Yat-sen Memorial Hospital, Guangzhou, Guangdong, China for diabetic foot ulcers needed lower extremity amputation surgery between July 2017 and March 2021. Detailed preoperative medical assessments were performed and recorded. Cardiac valve calcification was assessed using echocardiography at baseline. Oneyear follow-up assessments were conducted and included clinical visits, hospital record assessments, and telephone reviews to obtain the survival status of patients.

RESULTS

Ninety-three diabetic patients participated in the study. The 1-year follow-up mortality rate after amputation was 24.7%. Compared to the survival group, the prevalence of cardiac valve calcification and the Revised Cardiac Risk Index (RCRI) were higher in the mortality group. In the Cox regression analysis, cardiac valvular calcification (HR=3.427, 95% CI=1.125- 10.443, p =0.030) was found to be an independent predictor of all-cause mortality after amputation. In addition, the patients with both aortic valve calcification and mitral annular calcification had a higher all-cause mortality rate (50%). Receiver operator characteristic curve analysis showed a stronger predictive ability when using a combination of calcified valve number and RCRI (AUC=0.786 95%, CI=0.676-0.896, p =0.000).

CONCLUSION

In diabetic patients after lower-extremity amputation, cardiac valve calcification was associated with all-cause mortality during 1-year follow-up. Combination of calcified valve number and RCRI score showed a stronger predictive value for mortality.

Diabetic nephropathy: Focusing on pathological signals, clinical treatment, and dietary regulation

Diabetic nephropathy (DN) is one of the most severe complications of diabetes. However, due to its complex pathological mechanisms, no effective therapeutic methods (other than ACEIs and ARBs) have been applied, which have been used for many years in clinical practice. Recent studies have shown that emerging therapeutics, including novel target-based pharmacotherapy, cell therapies, and dietary regulation, are leading to new hopes for DN management. This review aims to shed new light on the treatment of DN by describing the important pathological mechanisms of DN and by analysing recent advances in clinical treatment, including drug therapy, cell therapy, and dietary regulation. In pathological mechanisms, RAAS activation, AGE accumulation, and EMT are involved in inflammation, cellular stress, apoptosis, pyroptosis, and autophagy. In pharmacotherapy, several new therapeutics, including SGLT2 inhibitors, GLP-1 agonists, and MRAs, are receiving public attention. In addition, stem cell therapies and dietary regulation are also being emphasized. Herein, we highlight the importance of combining therapy and dietary regulation in the treatment of DN and anticipate more basic research or clinical trials to verify novel strategies.

Cardiovascular complications of diabetes

INTRODUCTION

Type 2 diabetes mellitus (T2DM) is the ninth leading cause of mortality globally, and the prevalence continues to rise. Among individuals with T2DM, over two-thirds of deaths are caused by the cardiovascular complications of diabetes. These complications include atherosclerosis, coronary artery disease, nephropathy, stroke, thromboembolism, peripheral vascular disease. They have been long studied, and there are several theories as to the pathophysiology of how diabetes leads to these complications. The least understood mechanism is the pathophysiology linking diabetes to heart failure.

AREAS COVERED

This review focuses on the mechanisms of how T2DM leads to the aforementioned complications, particularly highlighting the development of heart failure. An extensive literature review of novel therapeutic options targeting the cardiovascular effects of T2DM was completed and summarized in this review.

EXPERT OPINION

This review finds that most studies to date have focused on the atherosclerotic vascular complications of diabetes. The pathophysiology between T2DM and heart failure is even less understood. Currently therapies that aim to decrease the risk of heart failure in diabetes are sparse. More research is required in order to better understand the changes at a cellular level and subsequently help providers to choose therapeutics that better target cardiovascular complications.

Hypercoagulability Impairs Plaque Stability in Diabetes-Induced Atherosclerosis

Diabetes mellitus, which is largely driven by nutritional and behavioral factors, is characterized by accelerated atherosclerosis with impaired plaque stability. Atherosclerosis and associated complications are the major cause of mortality in diabetic patients. Efficient therapeutic concepts for diabetes-associated atherosclerosis are lacking. Atherosclerosis among diabetic patients is associated with reduced endothelial thrombomodulin (TM) expression and impaired activated protein C (aPC) generation. Here, we demonstrate that atherosclerotic plaque stability is reduced in hyperglycemic mice expressing dysfunctional TM (TM^Pro/Pro mice), which have a pro-coagulant phenotype due to impaired thrombin inhibition and markedly reduced aPC generation. The vessel lumen and plaque size of atherosclerotic lesions in the truncus brachiocephalic were decreased in diabetic TM^Pro/Pro ApoE^-/- mice compared to diabetic ApoE^-/- mice. While lipid accumulation in lesions of diabetic TM^Pro/Pro ApoE^-/- mice was lower than that in diabetic ApoE^-/- mice, morphometric analyses revealed more prominent signs of instable plaques, such as a larger necrotic core area and decreased fibrous cap thickness in diabetic TM^Pro/Pro ApoE^-/- mice. Congruently, more macrophages and fewer smooth muscle cells were observed within lesions of diabetic TM^Pro/Pro ApoE^-/- mice. Thus, impaired TM function reduces plaque stability, a characteristic of hyperglycemia-associated plaques, thus suggesting the crucial role of impaired TM function in mediating diabetes-associated atherosclerosis.

Epigenetic Modifications and Non-Coding RNA in Diabetes-Mellitus-Induced Coronary Artery Disease: Pathophysiological Link and New Therapeutic Frontiers

Diabetes mellitus (DM) is a glucose metabolism disorder characterized by chronic hyperglycemia resulting from a deficit of insulin production and/or action. DM affects more than 1 in 10 adults, and it is associated with an increased risk of cardiovascular morbidity and mortality. Cardiovascular disease (CVD) accounts for two thirds of the overall deaths in diabetic patients, with coronary artery disease (CAD) and ischemic cardiomyopathy as the main contributors. Hyperglycemic damage on vascular endothelial cells leading to endothelial dysfunction represents the main initiating factor in the pathogenesis of diabetic vascular complications; however, the underlying pathophysiological mechanisms are still not entirely understood. This review addresses the current knowledge on the pathophysiological links between DM and CAD with a focus on the role of epigenetic modifications, including DNA methylation, histone modifications and noncoding RNA control. Increased knowledge of epigenetic mechanisms has contributed to the development of new pharmacological treatments ("epidrugs") with epigenetic targets, although these approaches present several challenges. Specific epigenetic biomarkers may also be used to predict or detect the development and progression of diabetes complications. Further studies on diabetes and CAD epigenetics are needed in order to identify possible new therapeutic targets and advance personalized medicine with the prediction of individual drug responses and minimization of adverse effects.

Diabetes Mellitus: A Path to Amnesia, Personality, and Behavior Change

Simple Summary

Diabetes Mellitus (DM) is a metabolic disorder resulting from a disturbance of insulin secretion, action, or both. Hyperglycemia and overproduction of superoxide induce the development and progression of chronic complications of DM. The impact of DM and its complication on the central nervous system (CNS) such as dementia and Alzheimer’s Disease (AD) still remain obscure. In dementia, there is a gradual decline in cognitive function. The incidence of dementia increases with age, and patient become socially, physically, and mentally more vulnerable and dependent. The symptoms often emerge decades after the onset of pathophysiology, thus impairing early therapeutic intervention. Most diabetic subjects who develop dementia are above the age of 65, but diabetes may also cause an increased risk of developing dementia before 65 years. Vascular dementia is the second most common form of dementia after AD. Type 2 DM (T2DM) increases the incidence of vascular dementia (since its covers the vascular system) and AD. The functional and structural integrity of the CNS is altered in T2DM due to increased synthesis of Aβ. Additionally, hyperphosphorylation of Tau protein also results from dysregulation of various signaling cascades in T2DM, thereby causing neuronal damage and AD. There is the prospect for development of a therapy that may help prevent or halt the progress of dementia resulting from T2DM.

Abstract

Type 2 diabetes mellitus is increasingly being associated with cognition dysfunction. Dementia, including vascular dementia and Alzheimer’s Disease, is being recognized as comorbidities of this metabolic disorder. The progressive hallmarks of this cognitive dysfunction include mild impairment of cognition and cognitive decline. Dementia and mild impairment of cognition appear primarily in older patients. Studies on risk factors, neuropathology, and brain imaging have provided important suggestions for mechanisms that lie behind the development of dementia. It is a significant challenge to understand the disease processes related to diabetes that affect the brain and lead to dementia development. The connection between diabetes mellitus and dysfunction of cognition has been observed in many human and animal studies that have noted that mechanisms related to diabetes mellitus are possibly responsible for aggravating cognitive dysfunction. This article attempts to narrate the possible association between Type 2 diabetes and dementia, reviewing studies that have noted this association in vascular dementia and Alzheimer’s Disease and helping to explain the potential mechanisms behind the disease process. A Google search for “Diabetes Mellitus and Dementia” was carried out. Search was also done for “Diabetes Mellitus”, “Vascular Dementia”, and “Alzheimer’s Disease”. The literature search was done using Google Scholar, Pubmed, Embase, ScienceDirect, and MEDLINE. Keeping in mind the increasing rate of Diabetes Mellitus, it is important to establish the Type 2 diabetes’ effect on the brain and diseases of neurodegeneration. This narrative review aims to build awareness regarding the different types of dementia and their relationship with diabetes.

Epigenetics in the pathogenesis of diabetic nephropathy

Diabetic nephropathy (DN), which is a common microvascular complication with a high incidence in diabetic patients, greatly increases the mortality of patients. With further study on DN, it is found that epigenetics plays a crucial role in the pathophysiological process of DN. Epigenetics has an important impact on the development of DN through a variety of mechanisms, and promotes the generation and maintenance of metabolic memory, thus ultimately leading to a poor prognosis. In this review we discuss the methylation of DNA, modification of histone, and regulation of non-coding RNA involved in the progress of cell dysfunction, inflammation and fibrosis in the kidney, which ultimately lead to the deterioration of DN.

Glucagon-Like Peptide-1 Receptor Agonists and Brain Vascular Function

Prevention of cardiovascular events and regression of atherosclerotic changes are the primary aims of preventive cardiovascular medicine. Arterial thrombosis is caused by endothelial dysfunction, which disrupts vascular haemostasis. Glucagon-like peptide 1 (GLP-1) receptor agonists have been initially used as glucose lowering agents, but over time have been used for other indications due to their cardiorenal benefit, as well as their benefit in the regression of atherosclerosis process. The aim of this paper is to present the benefits of GLP-1 receptor agonists in the prevention of atherosclerotic changes, in the preservation of brain vascular function, and to show the possible role in the treatment of neurodegenerative diseases.

S-nitrosylation-mediated coupling of G-protein alpha-2 with CXCR5 induces Hippo/YAP-dependent diabetes-accelerated atherosclerosis

Atherosclerosis-associated cardiovascular disease is one of the main causes of death and disability among patients with diabetes mellitus. However, little is known about the impact of S-nitrosylation in diabetes-accelerated atherosclerosis. Here, we show increased levels of S-nitrosylation of guanine nucleotide-binding protein G(i) subunit alpha-2 (SNO-GNAI2) at Cysteine 66 in coronary artery samples from diabetic patients with atherosclerosis, consistently with results from mice. Mechanistically, SNO-GNAI2 acted by coupling with CXCR5 to dephosphorylate the Hippo pathway kinase LATS1, thereby leading to nuclear translocation of YAP and promoting an inflammatory response in endothelial cells. Furthermore, Cys-mutant GNAI2 refractory to S-nitrosylation abrogated GNAI2-CXCR5 coupling, alleviated atherosclerosis in diabetic mice, restored Hippo activity, and reduced endothelial inflammation. In addition, we showed that melatonin treatment restored endothelial function and protected against diabetes-accelerated atherosclerosis by preventing GNAI2 S-nitrosylation. In conclusion, SNO-GNAI2 drives diabetes-accelerated atherosclerosis by coupling with CXCR5 and activating YAP-dependent endothelial inflammation, and reducing SNO-GNAI2 is an efficient strategy for alleviating diabetes-accelerated atherosclerosis.

The roles of immune cells in atherosclerotic calcification

Atherosclerosis is the leading cause of acute cardiovascular events, and vascular calcification is an important pathological phenomenon in atherosclerosis. Recently, many studies have shown that immune cells are closely associated with the development of atherosclerosis and calcification, but there are many conflicting viewpoints because of immune system complications, such as the pro-atherosclerotic and atheroprotective effects of regulatory B cells (Bregs), T helper type 2 (Th2) cells and T helper type 17 (Th17) cells. In this review, we summarize the studies on the roles of immune cells, especially lymphocytes and macrophages, in atherosclerotic calcification. Furthermore, we prepared graphs showing the relationship between T cells, B cells and macrophages and atherosclerotic calcification. Finally, we highlight some potential issues that are closely associated with the function of immune cells in atherosclerotic calcification. Based on current research results, this review summarizes the relationship between immune cells and atherosclerotic calcification, and it will be beneficial to understand the relationship of immune cells and atherosclerotic calcification.

Effects of insulin on the proliferation and global gene expression profile of A7r5 cells

Insulin contributes to atherosclerosis, but the potential mechanisms are kept unclear. In this study, insulin promoted proliferation of A7r5 cells. Microarray analysis indicated that insulin significantly changed 812 probe sets of genes, including 405 upregulated and 407 downregulated ones (fold change ≥ 1.5 or ≤ - 1.5; p < 0.05). Gene ontology analysis showed that the differentially expressed genes were involved in a number of processes, including the regulation of cell proliferation/migration/cycle, apoptotic process, oxidative stress, inflammatory response, mitogen-activated protein kinase (MAPK) activity, lipid metabolic process and extracellular matrix organization. Moreover, Kyoto Encyclopedia of Genes and Genomes pathway analysis indicated that the genes were involved in biosynthesis of amino acids, fatty acid metabolism, glycolysis/gluconeogenesis, metabolic pathways, regulation of autophagy, cell cycle and apoptosis, as well as the PI3K-Akt, MAPK, mTOR and NF-κB signaling pathways. Additionally, insulin enhanced phosphorylation of MAPK kinase 1/2 and Akt, suggesting activation of the MAPK and PI3K-Akt signaling pathways. Inhibition of ERK1/2 reduced insulin-induced proliferation. This study revealed the proliferative effects of insulin and displayed global gene expression profile of A7r5 cells stimulated by insulin, suggesting new insight into the molecular pathogenesis of insulin promoting atherosclerosis.

Prevalence of peripheral arterial disease and associated factors in people with type 2 diabetes

Abstract Introduction: The high rate of diabetes mellitus index (DM), along with the increase in cardiovascular compromise that DM favors, and the scarcity of epidemiological data regarding the prevalence of peripheral arterial disease (PAD) in this population, make it important to study risk factors associated with the development of PAD in the population with type 2 diabetes mellitus (DM2). Objective: To estimate the prevalence of PAD together with the associated factors in a sample of patients with DM2, treated in the Family Health Strategies (FHS) program, in the municipality of Pindamonhangaba, SP. Methods: Quantitative research in a cross-sectional study of 38 individuals who were diagnosed with DM2, between 40 and 77 years old, selected by convenience sampling and treated in the family health program in two different districts of the municipality. The method consisted of the evaluation of personal and anthropometric data, anamnesis and physical examination including the ankle-brachial index (ABI). Results: PAD was present in 21.1% (95%CI: 16.9 to 25.8) of the investigated population. Risk factors observed were age range of 51 to 69 years (75%), overweight (50%), systemic arterial hypertension (SAH) (100%), smoking (62.5%) and physical inactivity (87.5%). Conclusion: The prevalence of PAD was more than a fifth of those diagnosed with DM2, and the most prevalent associated risk factors were SAH, physical inactivity, smoking and overweight with and without PAD.

Pathophysiology of Type 2 Diabetes Mellitus

Type 2 Diabetes Mellitus (T2DM), one of the most common metabolic disorders, is caused by a combination of two primary factors: defective insulin secretion by pancreatic β-cells and the inability of insulin-sensitive tissues to respond appropriately to insulin. Because insulin release and activity are essential processes for glucose homeostasis, the molecular mechanisms involved in the synthesis and release of insulin, as well as in its detection are tightly regulated. Defects in any of the mechanisms involved in these processes can lead to a metabolic imbalance responsible for the development of the disease. This review analyzes the key aspects of T2DM, as well as the molecular mechanisms and pathways implicated in insulin metabolism leading to T2DM and insulin resistance. For that purpose, we summarize the data gathered up until now, focusing especially on insulin synthesis, insulin release, insulin sensing and on the downstream effects on individual insulin-sensitive organs. The review also covers the pathological conditions perpetuating T2DM such as nutritional factors, physical activity, gut dysbiosis and metabolic memory. Additionally, because T2DM is associated with accelerated atherosclerosis development, we review here some of the molecular mechanisms that link T2DM and insulin resistance (IR) as well as cardiovascular risk as one of the most important complications in T2DM.

Serum discrimination and phenotype assessment of coronary artery disease patents with and without type 2 diabetes prior to coronary artery bypass graft surgery

Diabetes Mellitus (DM) accelerates coronary artery disease (CAD) and atherosclerosis, the causes of most heart attacks. The biomolecules involved in these inter-related disease processes are not well understood. This study analyzes biomolecules in the sera of patients with CAD, with and without type (T) 2DM, who are about to undergo coronary artery bypass graft (CABG) surgery. The goal is to develop methodology to help identify and monitor CAD patients with and without T2DM, in order to better understand these phenotypes and to glean relationships through analysis of serum biomolecules. Aorta, fat, muscle, and vein tissues from CAD T2DM patients display diabetic-related histologic changes (e.g., lipid accumulation, fibrosis, loss of cellularity) when compared to non-diabetic CAD patients. The patient discriminatory methodology utilized is serum biomolecule mass profiling. This mass spectrometry (MS) approach is able to distinguish the sera of a group of CAD patients from controls (p value 10⁻¹⁵), with the CAD group containing both T2DM and non-diabetic patients. This result indicates the T2DM phenotype does not interfere appreciably with the CAD determination versus control individuals. Sera from a group of T2DM CAD patients however are distinguishable from non-T2DM CAD patients (p value 10⁻⁸), indicating it may be possible to examine the T2DM phenotype within the CAD disease state with this MS methodology. The same serum samples used in the CAD T2DM versus non-T2DM binary group comparison were subjected to MS/MS peptide structure analysis to help identify potential biochemical and phenotypic changes associated with CAD and T2DM. Such peptide/protein identifications could lead to improved understanding of underlying mechanisms, additional biomarkers for discriminating and monitoring these disease conditions, and potential therapeutic targets. Bioinformatics/systems biology analysis of the peptide/protein changes associated with CAD and T2DM suggested cell pathways/systems affected include atherosclerosis, DM, fibrosis, lipogenesis, loss of cellularity (apoptosis), and inflammation.

Identification of Susceptibility Modules and Genes for Cardiovascular Disease in Diabetic Patients Using WGCNA Analysis

OBJECTIVE

To identify susceptibility modules and genes for cardiovascular disease in diabetic patients using weighted gene coexpression network analysis (WGCNA).

METHODS

The raw data of GSE13760 were downloaded from the Gene Expression Omnibus (GEO) website. Genes with a false discovery rate < 0.05 and a log2 fold change ≥ 0.5 were included in the analysis. WGCNA was used to build a gene coexpression network, screen important modules, and filter the hub genes. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were performed for the genes in modules with clinical interest. Genes with a significance over 0.2 and a module membership over 0.8 were used as hub genes. Subsequently, we screened these hub genes in the published genome-wide SNP data of cardiovascular disease. The overlapped genes were defined as key genes.

RESULTS

Fourteen gene coexpression modules were constructed via WGCNA analysis. Module greenyellow was mostly significantly correlated with diabetes. The GO analysis showed that genes in the module greenyellow were mainly enriched in extracellular matrix organization, extracellular exosome, and calcium ion binding. The KEGG analysis showed that the genes in the module greenyellow were mainly enriched in antigen processing and presentation, phagosome. Fifteen genes were identified as hub genes. Finally, HLA-DRB1, LRP1, and MMP2 were identified as key genes.

CONCLUSION

This was the first study that used the WGCNA method to construct a coexpression network to explore diabetes-associated susceptibility modules and genes for cardiovascular disease. Our study identified a module and several key genes that acted as essential components in the etiology of diabetes-associated cardiovascular disease, which may enhance our fundamental knowledge of the molecular mechanisms underlying this disease.

A double-blind placebo-controlled clinical trial testing the effect of hyperbaric oxygen therapy on brain and cognitive outcomes of mildly cognitively impaired elderly with type 2 diabetes: Study design

INTRODUCTION

Type 2 diabetes (T2D) is a risk factor for dementia. Ischemia due to vascular pathology is hypothesized to be an underlying mechanism for this association. Hyperbaric oxygen therapy (HBOT) is a treatment in which oxygen-enriched air (up to 100%) is administered to patients in a chamber at a pressure above one atmosphere absolute. HBOT is approved for the treatment of T2D ischemic non-healing wounds. Evidence from animal studies and small clinical trials suggests that HBOT improves hypoxic/ischemic brain injuries, consequently inducing brain angiogensis, leading to cognitive improvement.

METHODS

We present the design of the first double-blind, placebo-controlled, clinical trial on brain and cognitive outcomes in elderly (n = 154) with T2D and mild cognitive impairment to compare the effects of HBOT versus sham (normal air with 1.1 ATA pressure in the first and last 5 minutes of the session). Eligible candidates are randomized with equal probability to HBOT and sham. Outcomes are assessed before and after treatment, and at 6- and 12-month follow-up. The primary cognitive outcome is global cognitive change, indexed by a composite sum of z-scores of four executive functions and four episodic memory tests. The primary neurobiological outcome is cerebral blood flow (CBF; via arterial spin labeling magnetic resonance imaging [ASL-MRI]) and cerebral glucose utilization via fluorodeoxyglucose positron emission tomography (FDG-PET). Secondary outcome measures are specific cognitive domains (executive function and episodic memory) and functional measures (Clinical Dementia Rating sum of boxes, activities of daily living). Efficacy analyses will be performed for the intent-to-treat sample.

DISCUSSION

Recent studies suggest that HBOT induces neuroplasticity and improves cognition in post-stroke and traumatic brain injury patients. However, its effect on cognition, cerebral blood flow, and brain glucose utilization in T2D patients at high dementia risk is yet to be determined. If effective, this study may provide strong evidence for the brain and cognitive benefits of HBOT in this population.

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.

Nε-Carboxymethyl-Lysine Negatively Regulates Foam Cell Migration via the Vav1/Rac1 Pathway

Background

Macrophage-derived foam cells play a central role in atherosclerosis, and their ultimate fate includes apoptosis, promotion of vascular inflammation, or migration to other tissues. Nε-Carboxymethyl-lysine (CML), the key active component of advanced glycation end products, induced foam cell formation and apoptosis. Previous studies have shown that the Vav1/Rac1 pathway affects the macrophage cytoskeleton and cell migration, but its role in the pathogenesis of diabetic atherosclerosis is unknown.

Methods and Results

In this study, we used anterior tibiofibular vascular samples from diabetic foot amputation patients and accident amputation patients, and histological and cytological tests were performed using a diabetic ApoE^−/− mouse model and primary peritoneal macrophages, respectively. The results showed that the atherosclerotic plaques of diabetic foot amputation patients and diabetic ApoE^−/− mice were larger than those of the control group. Inhibition of the Vav1/Rac1 pathway reduced vascular plaques and promoted the migration of macrophages to lymph nodes. Transwell and wound healing assays showed that the migratory ability of macrophage-derived foam cells was inhibited by CML. Cytoskeletal staining showed that advanced glycation end products inhibited the formation of lamellipodia in foam cells, and inhibition of the Vav1/Rac1 pathway restored the formation of lamellipodia.

Conclusion

CML inhibits the migration of foam cells from blood vessels via the Vav1/Rac1 pathway, and this process affects the formation of lamellipodia.

Brain-derived neurotrophic factor alleviates diabetes mellitus-accelerated atherosclerosis by promoting M2 polarization of macrophages through repressing the STAT3 pathway

Diabetes mellitus-accelerated atherosclerosis (DMAS) is one of the vascular complications of diabetes. Brain-derived neurotrophic factor (BDNF) plays a critical role in diabetes mellitus. However, the mechanism by which BDNF is involved in DMAS remains unknown. This study investigates the effect of BDNF on the progression of DMAS as well as the underlying mechanism of action. The levels of BDNF in serum and peripheral blood mononuclear cells (PBMCs) from patients with DMAS and health controls were measured as well as the expression of inflammatory cytokines (IL-1β, TNF-α, IL-10, TGF-β and IL-13). The effects of BDNF restoration on cytokine release, macrophage differentiation and the formation of atherosclerotic plaques were evaluated both in vitro and in vivo using the DMAS mouse model. Downregulation of BDNF was identified in the serum and PBMCs of patients with DMAS. Elevation of BDNF contributed to a reduction in the AS lesion area in low-density lipoprotein receptor^-/- mice, inactivated the STAT3 pathway, decreased pro-inflammatory cytokines IL-1β and TNF-α, and increased IL-10, TGF-β and IL-13. BDNF overexpression also increased the proportion of M2 macrophages and alleviated atherosclerotic lesions. Our findings demonstrate that BDNF overexpression promotes M2 macrophage polarization, which represses the development of DMAS by inactivating the STAT3 pathway.

Treatment of Peroxidase Derived from Foxtail Millet Bran Attenuates Atherosclerosis by Inhibition of CD36 and STAT3 in Vitro and in Vivo

Atherosclerosis is one of the main causes of cardiovascular diseases. Our previous study indicated that a type of peroxidase derived from foxtail millet bran (FMBP) had prominent antitumor activities. In the present study, we found that FMBP had potential antiatherosclerosis effects. The results showed that FMBP treatment strongly suppressed lipid phagocytosis in both HASMCs and THP-1 cells by 52% and 49%, respectively. Further, FMBP significantly inhibited HASMCs migration by promoting transformation of HASMCs from synthetic to contractile, leading to the decrease of lipid phagocytosis. Simultaneously, FMBP repressed lipid uptake by reducing the expression of CD36 in THP-1 cells. In addition, FMBP reduced the secretion of inflammatory factor IL-1β by inhibiting the expression of STAT3 in THP-1 cells. Interestingly, FMBP also had the same effects in models of atherosclerosis constructed with ApoE-/- mice, including decreased aortic lesion area, repressed aortic sinus CD36 and STAT3 expression, and elevated serum HDL-C concentration. Collectively, these results indicate that FMBP has great potential in preventing the development of atherosclerosis.

Spinal Cord Ischemia in Pancreas Transplantation: The UK Experience

BACKGROUND

Spinal cord ischemia (SCI) is a rare but devastating condition that can occur in the perioperative period resulting in paraplegia. Although diabetes mellitus is a risk factor for SCI in other types of major surgery, SCI is not widely recognized in transplantation. The aim of this study was to quantify the risk of SCI in pancreatic transplantation.

METHODS

All UK pancreas transplant units were surveyed between 2017 and 2018. The risk of SCI in pancreas transplantation was estimated using the number of radiologically confirmed cases relative to the number of pancreatic transplants from UK registry data during the same time period.

RESULTS

There have been 6 cases of SCI during pancreas transplantation since 2002. No aortic clamping occurred in any recipient. During or after surgery, all patients experienced episodes of hypotension (systolic blood pressure ≤ 90 mm Hg) before the onset of neurological symptoms. Epoprostenol, epidural anesthesia, and postoperative hemodialysis may have contributed to systemic hypotension. The mainstay of early treatment for SCI for all cases was blood pressure control.

CONCLUSIONS

Based on these findings, there is approximately a 1:440 risk of SCI in pancreas transplantation. Hypotension appears to be a prominent risk factor. Strategies for mitigating the risk of SCI are discussed, drawing on evidence from thoraco-abdominal aortic aneurysm surgery. The risk of long-term neurological deficit should be discussed with prospective pancreas recipients given the potential impact on posttransplant quality of life.

Varinostat Alters Gene Expression Profiles in Aortic Tissues from ApoE-/- Mice

Atherosclerosis (AS) is a complex, chronic inflammatory disease that is characterized by plaque buildup within arterial vessel walls. Preclinical trials have suggested that vorinostat, a pan-histone deacetylase inhibitor (HDACi), reduces vascular inflammation and AS, but the underlying protective mechanism has not been fully elucidated. The present study aimed to identify altered gene expression profiles in aortic tissues from ApoE^-/- mice after vorinostat treatment. Male ApoE-/- mice fed a high-fat diet were treated with either vorinostat or vehicle, and the aortic plaque area was quantified 8 weeks after treatment. Aortic tissues were collected from both the vorinostat group (n = 3) and vehicle group (n = 3) for deep sequencing of the cDNA to construct sRNA libraries. Oral administration of vorinostat significantly reduced plaque size in the ApoE^-/- mice (p < 0.05). In total, 1,550 differentially expressed mRNAs, 56 differentially expressed miRNAs, and 381 differentially expressed lncRNAs were identified in the vorinostat group compared to the vehicle group. Subsequently, a global lncRNA-miRNA-mRNA triple network was constructed based on the competitive endogenous RNA (ceRNA) theory. The hepatitis C signaling pathway was significantly enriched among the differentially expressed mRNAs from the ceRNA network, which suggests that vorinostat has anti-inflammatory properties. Importantly, the identified target pair of mmu-miR-3075-5p/lncRNA-A330023F24Rik/Ldlr may regulate drug response. Upregulation of low-density lipid receptor (Ldlr) and lncRNA-A330023F24Rik and downregulation of mmu-miR-3075-5p were further verified by quantitative real-time polymerase chain reaction. To conclude, vorinostat reduced AS in ApoE^-/- mice. Differentially expressed mRNA, lncRNAs, and miRNAs, as well as their interactions and pathways, were identified, which partially explain vorinostat's anti-atherosclerotic effects.

MicroRNA profiling of diabetic atherosclerosis in a rat model

OBJECTIVE

The incidence of diabetic atherosclerosis (DA) is increasing worldwide. The study aim was to identify differentially expressed microRNAs (DE-miRs) potentially associated with the initiation and/or progression of DA, thereby yielding new insights into this disease.

METHODS

Matched iliac artery tissue samples were isolated from 6 male rats with or without DA. The Affymetrix GeneChip microRNA 4.0 Array was used to detect miRs. Differential expression between atherosclerotic group and non-atherosclerotic group samples was analyzed using the Gene-Cloud of Biotechnology Information platform. Targetscan and miRanda were then used to predict targets of DE-miRs. Functions and pathways were identified for significantly enriched candidate target genes and a DE-miR functional regulatory network was assembled to identify DA-associated core target genes.

RESULTS

A total of nine DE-miRs (rno-miR-206-3p, rno-miR-133a-5p, rno-miR-133b-3p, rno-miR-133a-3p, rno-miR-325-5p, rno-miR-675-3p, rno-miR-411-5p, rno-miR-329-3p, and rno-miR-126a-3p) were identified, all of which were up-regulated and together predicted to target 3349 genes. The target genes were enriched in known functions and pathways related to lipid and glucose metabolism. The functional regulatory network indicated a modulatory pattern of these metabolic functions with DE-miRs. The miR-gene network suggested arpp19 and MDM4 as possible DA-related core target genes.

CONCLUSION

The present study identified DE-miRs and miRNA-gene networks enriched for lipid and glucose metabolic functions and pathways, and arpp19 and MDM4 as potential DA-related core target genes, suggesting DE-miRs and/or arpp19 and MDM4 could act as potential diagnostic markers or therapeutic targets for DA.

Activated protein C reverses epigenetically sustained p66Shc expression in plaque-associated macrophages in diabetes

Impaired activated protein C (aPC) generation is associated with atherosclerosis and diabetes mellitus. Diabetes-associated atherosclerosis is characterized by the hyperglycaemic memory, e.g., failure of disease improvement despite attenuation of hyperglycaemia. Therapies reversing the hyperglycaemic memory are lacking. Here we demonstrate that hyperglycaemia, but not hyperlipidaemia, induces the redox-regulator p66Shc and reactive oxygen species (ROS) in macrophages. p66Shc expression, ROS generation, and a pro-atherogenic phenotype are sustained despite restoring normoglycemic conditions. Inhibition of p66Shc abolishes this sustained pro-atherogenic phenotype, identifying p66Shc-dependent ROS in macrophages as a key mechanism conveying the hyperglycaemic memory. The p66Shc-associated hyperglycaemic memory can be reversed by aPC via protease-activated receptor-1 signalling. aPC reverses glucose-induced CpG hypomethylation within the p66Shc promoter by induction of the DNA methyltransferase-1 (DNMT1). Thus, epigenetically sustained p66Shc expression in plaque macrophages drives the hyperglycaemic memory, which-however-can be reversed by aPC. This establishes that reversal of the hyperglycaemic memory in diabetic atherosclerosis is feasible.

Alpha-amylase inhibitors from mycelium of an oyster mushroom

The α-Amylase and α-glucosidase are two main enzymes involved in carbohydrate metabolism. This study was aimed at detecting alpha-amylase inhibitory activity from edible mushroom mycelia. Oyster mushroom was collected from a natural source, from Indian Institute of Technology (Banaras Hindu University) campus and was maintained in vitro in mycelial form. Chloroform, acetone, methanol, and water were used separately for extraction of an active constituent from mycelial cells grown, for 7 days, in potato dextrose broth. The extracts were tested for alpha-amylase inhibitory activity. Chloroform, acetone, and methanol extracts were found to have alpha-amylase inhibitory activity, with IC₅₀ values of 1.71, 224, and 383 μg/mL, respectively. Aqueous extract had no enzyme inhibitory activity. The acetone extract inhibited α-amylase non-competitively whereas chloroform extract showed competitive inhibition. Acetone extraction yielded highest total phenolic content (TPC) of 0.524 mM of gallic acid equivalent, whereas chloroform extraction resulted in lowest TPC of 0.006 mM. The HPLC and absorbance maxima of acetone and chloroform extracts suggest that the bioactive component responsible for enzyme inhibition could be glycoproteins in chloroform extract and catechins (flavonoids) in acetone extract. Thus, the mushroom mycelia under study may be exploited for production and purification of a lead compound for the development of the α-amylase inhibitory drug.

Ginsenoside Rg3 Mitigates Atherosclerosis Progression in Diabetic apoE-/- Mice by Skewing Macrophages to the M2 Phenotype

Atherosclerosis (AS) in diabetic patients is often associated with low stability, which might be largely attributed to unfavorable macrophage polarization and increased inflammatory response induced by hyperglycaemia. Ginsenoside Rg3 is one of the main active principles of Panax Ginseng, which has been reported to be a natural ligand of peroxisome proliferator-activated receptor-gamma (PPARγ), a key nuclear transcriptional factor involved in inflammation and macrophage differentiation. However, it remains unclear if Rg3 could exert protective effects on plaque stability in diabetes. In this study, we investigated the role of ginsenoside 20(S)-Rg3 in macrophage polarization and AS plaque stability using advanced glycation end products-treated macrophages and diabetic AS mice models. In vitro, advanced glycation end products (AGEs) treatment promoted the expression of proinflammatory molecules and M1 surface markers, whereas 20(S)-Rg3 could reverse the M1 polarization to the M2 phenotype. In vivo, the administration of 20(S)-Rg3 promoted AS lesion stability and reduced the plaque burden, accompanied by increased M2 macrophages and reduced M1 macrophages. In addition, PPARγ antagonist GW9662 co-administration mostly blocked these effects, suggesting the important role of PPARγ pathways in mediating 20(S)-Rg3 effects in macrophage polarization and atherosclerosis progression. Together, these results demonstrated an immunomodulatory role of ginsenoside 20(S)-Rg3 in promoting macrophages to a profile of the M2 type through PPARγ-dependent mechanisms, and indicated a potential role of 20(S)-Rg3 in the prevention and treatment of diabetic atherosclerosis.

Tissue Oxygenation and Negative-Pressure Wound Therapy When Applied to the Feet of Persons With Diabetes Mellitus: An Observational Study

PURPOSE

Our group has reported that negative-pressure wound therapy (NPWT) decreases tissue oxygenation by 84% in the foot of diabetic patients because the pad of the connecting drainage tube and foam sponge of the NPWT system compress the wound bed. The purpose of this study was to determine whether an NPWT modified dressing application reduces tissue oxygenation in the feet of persons with diabetes mellitus.

DESIGN

A prospective, clinical, observational study.

SUBJECTS AND SETTING

We enrolled 30 patients with diabetic mellitus; their mean age was 63.9 ± 11.2 years (mean ± standard deviation). All were cared for at the diabetic wound center at an academic tertiary medical center in South Korea between 2014 and January 2015.

METHODS

Transcutaneous partial oxygen pressures (TcpO2) were measured to determine tissue oxygenation levels beneath modified NPWT dressings. A TcpO2 sensor was fixed at the tarsometatarsal area of the contralateral unwounded foot. A negative pressure of -125 mm Hg was applied until TcpO2 reached a plateau state; values were measured before, during, and after the modified NPWT. The Wilcoxon' and Mann-Whitney U tests were used to compare differences between these measurements.

RESULTS

TcpO2 levels decreased by 26% during the modified NPWT. Mean TcpO2 values before, during, and after turning off the therapy were 54.3 ± 15.3 mm Hg, 41.6 ± 16.3 mm Hg, and 53.3 ± 15.6 mm Hg (P < .05), respectively.

CONCLUSION

Applying NPWT without the pad of the connecting drainage tube significantly reduces the amount of tissue oxygenation loss beneath foam dressings on the skin of the foot dorsum in diabetic patients.

Suppression of Abdominal Aortic Aneurysm Formation in Mice by Teneligliptin, a Dipeptidyl Peptidase-4 Inhibitor

Aim: Dipeptidyl peptidase-4 (DPP-4) inhibitors lower blood glucose levels through inhibition of incretin degradation, which stimulates insulin secretion. Recent studies reported that DPP-4 inhibitors suppressed atherogenesis in apolipoprotein E-knockout (ApoEKO) mice. In this study, we investigated whether teneligliptin, a DPP-4 inhibitor, affects the development of abdominal aortic aneurysms (AAA) in ApoEKO mice.

Methods: ApoEKO mice were fed a high-fat diet (HFD) and infused with angiotensin (Ang) II by osmotic mini pumps for 4 weeks to induce AAA with (DPP-4i group) or without (control group) teneligliptin administered orally from 1 week before HFD and Ang II infusion to the end of the experiment. Confluent rat vascular smooth muscle cells (VSMCs) were serum-starved for 48 hours, then incubated with or without teneligliptin for another 24 hours and stimulated with Ang II.

Results: Treatment with teneligliptin significantly reduced the AAA formation rate (30.7% vs. 71.4% vs. control, P < 0.05), aortic dilatation (1.32 ± 0.09 mm vs. 1.76 ± 0.18 mm in the control, P < 0.05) and severity score (0.75 ± 0.28 vs. 1.91 ± 0.4 in the control, P < 0.05). Elastin degradation grade was also attenuated in DPP-4i group (2.83 ± 0.17 vs. 3.45 ± 0.16 in the control, P < 0.05). The number of macrophages infiltrating into the abdominal aorta was decreased in the DPP-4i group (51.8 ± 29.8/section vs. 219.5 ± 78.5/section in the control, P < 0.05). Teneligliptin attenuated Ang II-induced phosphorylation of extracellular signal-regulated kinase (ERK) and Akt, and mRNA expression of monocyte chemoattractant protein-1 in VSMCs.

Conclusion: Treatment with teneligliptin suppressed AAA formation in ApoEKO mice with HFD and Ang II infusion. Suppression of macrophage infiltration by teneligliptin may be involved in the inhibition of AAA formation.

[Diabetic dyslipidemia and microvascular complications of diabetes]

Diabetic dyslipidemia is one of the main risk factors for atherosclerosis. Although its participation in diabetic microvascular complications is not that dominant, dyslipidemia may play an important role in formation and progression of these complications. Pathophysiological mechanisms by which diabetic dyslipidemia affects the etiopathogenesis of diabetic nephropathy, retinopathy, neuropathy and diabetic foot are presented. The data from clinical studies and treatment possibilities for particular microvascular complications using lipid-lowering therapy are discussed.Key words: diabetes mellitus - diabetic foot - dyslipidemia - nephropathy - neuropathy - retinopathy.

Diabetic polyneuropathy, deep white matter lesions, and carotid atherosclerosis: is there any association?

The morphologic and functional damages of diabetes mellitus (DM) on microcirculation can play a role in the pathogenesis of both polyneuropathy and cerebral white matter lesions. The aim of this study is to investigate the relation between polyneuropathy and cerebral deep white matter lesions (DWMLs) and carotid atherosclerosis in patients with type 2 DM. Sixty-six patients with type 2 DM without any disorder that may cause polyneuropathy, and vascular risk factors except for DM and hyperlipidemia were included in the study. DWMLs and carotid atherosclerosis were investigated in patients with and without polyneuropathy. Forty patients (60.6%) had diabetic sensorimotor polyneuropathy. DWMLs were more frequent in patients with polyneuropathy compared to patients without polyneuropathy (p = 0.003). Logistic regression analysis confirmed association between polyneuropathy and DWMLs after adjusted for age (p = 0.013), duration of DM (p = 0.007), and both age and duration of DM (p = 0.016). No statistically significant difference was found between patients with and without polyneuropathy for carotid atherosclerosis. Among patients with polyneuropathy, those having DWMLs had higher mean age (p = 0.003) and longer symptom duration (p = 0.020) compared to patients without DWMLs. No association was found between DWMLs and carotid atherosclerosis. Polyneuropathy and cerebral DWMLs in type 2 DM patients may share common pathogenesis; presence and duration of polyneuropathy symptoms may predict ischemic white matter damage independent of carotid atherosclerosis.

Cardiovascular inflammation is reduced with methotrexate in diabetes

Diabetes increases the risk of vascular events and mortality. While earlier type 2 diabetes trials demonstrated that intensive glucose lowering reduces microvascular complications, it is only recently that treatment with some of the newer antihyperglycemic agents has been associated with macrovascular benefits. We report herein that db/db mice concomitantly fed the Western diet and treated with the anti-inflammatory agent methotrexate display a less aggressive inflammatory (lower serum IL-1β, IL-6, SDF-1, and TNFα levels; higher circulating adiponectin, IL-12p70 and IL-10 concentrations; lower aortic VCAM-1 levels) profile than their saline-treated counterpart. Furthermore, acetylcholine-elicited endothelium-dependent vasodilatation was significantly greater in thoracic aortic segments from the former group. Collectively, the data lend support to the notion that alterations in the inflammatory system may be involved in the macrovascular benefits observed in type 2 diabetes trials and provide credence for the development of anti-inflammatory tools to lower CV risk and CV events in diabetes.

Diabetes for Cardiologists: Practical Issues in Diagnosis and Management

Diabetes mellitus (DM), a chronic metabolic disease characterized by hyperglycemia, is a profound cardiovascular (CV) risk factor. It compounds the effects of all other risk factors, leads to premature micro- and macrovascular disease, facilitates development of heart failure, worsens the clinical course of all CV diseases, and shortens life expectancy. Established DM, unrecognized DM, and dysglycemia that may progress to DM are all commonly present at the time of presentation of overt CV disease. Thus, CV specialists and trainees frequently treat patients with dysglycemia. The traditional and proven role of cardiologists in reducing the risk of macrovascular events in this population is through aggressive lipid and blood pressure treatment. However, a more proactive role in the detection and management of DM is likely to become increasingly important as the prevalence continues to increase and therapies continue to improve. The latter include antihyperglycemic therapies with proven cardiovascular safety profiles and CV event reduction properties not yet fully elucidated and not necessarily related to glycemic control. Accordingly, the purpose of this article is to (1) expand the interest of cardiologists in earlier stages of the natural history of DM, when prevention or early detection might help achieve greatest benefit; (2) highlight principles of optimal glycemic management, with an emphasis on add-on choices showing promising reduction of CV events and lacking CV adverse effects; and (3) encourage cardiologists to become proactive partners in the multidisciplinary care needed to ensure optimal lifelong vascular health in patients with, or who are at risk of, DM.

In Patients with Coronary Artery Disease and Type 2 Diabetes, SIRT1 Expression in Circulating Mononuclear Cells Is Associated with Levels of Inflammatory Cytokines but Not with Coronary Lesions

While SIRT1 is significantly associated with atherosclerosis and diabetic complications, its relevance to coronary lesions in patients with coronary artery disease and type 2 diabetes has not been specifically investigated. Thus, we assessed SIRT1 expression in peripheral blood mononuclear cells in these patients. We found that SIRT1 expression did not significantly correlate with syntax scores from coronary angiography (p > 0.05). Notably, plasma levels of the inflammatory cytokines tumor necrosis factor-α, monocyte chemoattractant protein-1, and high-sensitivity C-reactive protein were markedly higher in diabetic patients (p < 0.05). In addition, SIRT1 expression was negatively correlated with levels of these cytokines, as well as that of interleukin-6 (p < 0.05). In summary, the data indicate that SIRT1 expression in peripheral blood mononuclear cells is significantly correlated with inflammatory cytokines levels in patients with coronary artery disease and type 2 diabetes but not with the severity of coronary lesions.

TLR4 antagonist attenuates atherogenesis in LDL receptor-deficient mice with diet-induced type 2 diabetes

Although a large number of studies have well documented a key role of toll-like receptor (TLR)4 in atherosclerosis, it remains undetermined if TLR4 antagonist attenuates atherogenesis in mouse model for type 2 diabetes. In this study, we induced type 2 diabetes in low-density lipoprotein receptor-deficient (LDLR(-/-)) mice by high-fat diet (HFD). At 8 weeks old, 20 mice were fed HFD and 20 mice fed regular chow (RC) for 24 weeks. In the last 10 weeks, half HFD-fed mice and half RC-fed mice were treated with Rhodobacter sphaeroides lipopolysaccharide (Rs-LPS), an established TLR4 antagonist. After the treatment, atherosclerotic lesions in aortas were analyzed. Results showed that the HFD significantly increased bodyweight, glucose, lipids including total cholesterol, triglycerides and free fatty acids, and insulin resistance, indicating that the HFD induced type 2 diabetes in LDLR(-/-) mice. Results also showed that Rs-LPS had no effect on HFD-increased metabolic parameters in both nondiabetic and diabetic mice. Lipid staining of aortas and histological analysis of cross-sections of aortic roots showed that diabetes increased atherosclerotic lesions, but Rs-LPS attenuated atherogenesis in diabetic mice. Furthermore, immunohistochemical studies showed that Rs-LPS reduced infiltration of monocytes/macrophages and expression of interleukin (IL)-6 and matrix metalloproteinase-9 in atherosclerotic lesions of diabetic mice. Finally, the antagonistic effect of Rs-LPS on TLR4 was demonstrated by our in vitro studies showing that Rs-LPS inhibited IL-6 secretion from macrophages and endothelial cells stimulated by LPS or LPS plus saturated fatty acid palmitate. Taken together, our study demonstrated that TLR4 antagonist was capable of attenuating vascular inflammation and atherogenesis in mice with HFD-induced type 2 diabetes.

Methyl-γ-butyrobetaine decreases levels of acylcarnitines and attenuates the development of atherosclerosis

OBJECTIVE

The elevation of the levels of l-carnitine and its fatty acid esters, acylcarnitines, in tissue or plasma has been linked to the development of atherosclerosis. Recently, a potent inhibitor of l-carnitine biosynthesis and transport, methyl-γ-butyrobetaine (methyl-GBB), was discovered. In this study, we evaluated the effects of γ-butyrobetaine (GBB), l-carnitine and methyl-GBB administration on the progression of atherosclerosis.

METHODS

Apolipoprotein E knockout (apoE(-/-)) mice were treated with methyl-GBB, l-carnitine or GBB for 4months. Following the treatment, the amount of atherosclerotic lesions, the number of immune cells in atherosclerotic lesions and the plasma lipid profile were analysed. The l-carnitine and acylcarnitine levels were determined in the aortic tissues of CD-1 outbred mice 2weeks after treatment with methyl-GBB at the dose of 10mg/kg.

RESULTS

Treatment with methyl-GBB decreased the acylcarnitine and l-carnitine levels in the aortic tissues by seventeen- and ten-fold, respectively. Methyl-GBB treatment at a dose of 10mg/kg reduced the size of atherosclerotic plaques by 36%. Neither l-carnitine nor GBB treatment affected the development of atherosclerosis.

CONCLUSIONS

Methyl-GBB administration significantly attenuated the development of atherosclerosis in apoE(-/-)mice. Our results demonstrate that decreasing the acylcarnitine pools can attenuate the development of atherosclerosis.

Hyperglycemia has no effect on development of restenosis after percutaneous transluminal angioplasty (PTA) in a diabetic rabbit model

It is well known that hyperglycemia is a trigger of atherosclerosis in patients with diabetes mellitus. However, the role of hyperglycemia in restenosis remains unclear. In this study, we investigated the effects of hyperglycemia on restenosis. Stenosis was evaluated in two sets of diabetic rabbit models: i) diabetic restenosis versus nondiabetic restenosis and ii) diabetic atherosclerosis versus nondiabetic atherosclerosis. Our results indicated that there was no difference in rates of stenosis between the diabetic and the nondiabetic groups in restenosis rabbit models. However, the incidence of stenosis was significantly higher in the diabetic atherosclerosis group compared with the nondiabetic atherosclerosis group. Similarly, the intima-media thickness and cell proliferation rate were significantly increased in the diabetic atherosclerosis group compared with the nondiabetic atherosclerosis group, but there was no difference between the diabetic restenosis and the nondiabetic restenosis groups. Our results indicate that hyperglycemia is an independent risk factor for atherosclerosis, but it has no evident effect on restenosis. These findings indicate that the processes of atherosclerosis and restenosis may involve different pathological mechanisms.

Histone deacetylases and atherosclerosis

Atherosclerosis is the most common pathological process that leads to cardiovascular diseases, a disease of large- and medium-sized arteries that is characterized by a formation of atherosclerotic plaques consisting of necrotic cores, calcified regions, accumulated modified lipids, smooth muscle cells (SMCs), endothelial cells, leukocytes, and foam cells. Recently, the question about how to suppress the occurrence of atherosclerosis and alleviate the progress of cardiovascular disease becomes the hot topic. Accumulating evidence suggests that histone deacetylases(HDACs) play crucial roles in arteriosclerosis. This review summarizes the effect of HDACs and HDAC inhibitors(HDACi) on the progress of atherosclerosis.