Diabetes-associated Vascular Diseases Research Articles

DYRK1B inhibition exerts senolytic effects on endothelial cells and rescues endothelial dysfunctions

Aging is the major risk factor for chronic disease development. Cellular senescence is a key mechanism that triggers or contributes to age-related phenotypes and pathologies. The endothelium, a single layer of cells lining the inner surface of a blood vessel, is a critical interface between blood and all tissues. Many studies report a link between endothelial cell senescence, inflammation, and diabetic vascular diseases. Here we identify, using combined advanced AI and machine learning, the Dual Specificity Tyrosine Phosphorylation Regulated Kinase 1B (DYRK1B) protein as a possible senolytic target for senescent endothelial cells. We demonstrate that upon induction of senescence in vitro DYRK1B expression is increased in endothelial cells and localized at adherens junctions where it impairs their proper organization and functions. DYRK1B knock-down or inhibition restores endothelial barrier properties and collective behavior. DYRK1B is therefore a possible target to counteract diabetes-associated vascular diseases linked to endothelial cell senescence.

Animal models of diabetes-associated vascular diseases: an update on available models and experimental analysis.

Diabetes is a chronic metabolic disorder associated with the accelerated development of macrovascular (atherosclerosis and coronary artery disease) and microvascular complications (nephropathy, retinopathy and neuropathy), which remain the principal cause of mortality and morbidity in this population. Current understanding of cellular and molecular pathways of diabetes-driven vascular complications, as well as therapeutic interventions has arisen from studying disease pathogenesis in animal models. Diabetes-associated vascular complications are multi-faceted, involving the interaction between various cellular and molecular pathways. Thus, the choice of an appropriate animal model to study vascular pathogenesis is important in our quest to identify innovative and mechanism-based targeted therapies to reduce the burden of diabetic complications. Herein, we provide up-to-date information on available mouse models of both Type 1 and Type 2 diabetic vascular complications as well as experimental analysis and research outputs. LINKED ARTICLES: This article is part of a themed issue on Preclinical Models for Cardiovascular disease research (BJP 75th Anniversary). To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v179.5/issuetoc.

Rhodiola crenulata Suppresses High Glucose-Induced Matrix Metalloproteinase Expression and Inflammatory Responses by Inhibiting ROS-Related HMGB1-TLR4 Signaling in Endothelial Cells.

Rhodiola crenulata, a popular folk medicine for anti-altitude sickness in Tibet, has been shown to have protective effects against high glucose (HG)-induced endothelial cell dysfunction in human umbilical vein endothelial cells (HUVECs). However, its mechanisms of action are unclear. Here, we aimed to examine the effects and the mechanisms of action of Rhodiola crenulata extract (RCE) on matrix metalloproteinases (MMPs) and inflammatory responses under HG conditions. HUVECs were pretreated with RCE or untreated and then exposed to 33mM glucose medium for 24h. The levels of oxidative stress markers, MMPs, endogenous tissue inhibitors of MMPs (TIMPs), and adhesion molecules were determined. Zymography assays were also carried out. We found that RCE significantly decreased HG-induced increases in reactive oxygen species (ROS) and activation of MAPK and NF-B pathways. In addition, RCE not only significantly reduced the expression and activities of MMPs but also upregulated TIMP protein levels. Consistently, HG-induced activation of the toll-like receptor 4 (TLR4)/myeloid differentiation primary response protein (MyD88) signaling pathway, intracellular adhesion molecule-1 (ICAM-1), vascular adhesion molecule-1 (VCAM-1), and high mobility group box 1 (HMGB1) as well as endothelial cell apoptosis was inhibited by RCE treatment. RCE exerts protective effects on endothelial cells against HG insult, partially by suppressing the HMGB1/TLR4 axis. These findings indicate that Rhodiola crenulata may be a potential therapeutic agent for diabetes-associated vascular diseases.

Notoginsenoside Fc Accelerates Reendothelialization following Vascular Injury in Diabetic Rats by Promoting Endothelial Cell Autophagy.

Interventional therapies, such as percutaneous transluminal angioplasty and endovascular stent implantation, are used widely for the treatment of diabetic peripheral vascular complications. Reendothelialization is an essential process in vascular injury following interventional therapy, and hyperglycemia in diabetes mellitus (DM) plays an important role in damaging endothelial layer integrity, leading to the retardance of reendothelialization and excessive neointimal formation. Notoginsenoside Fc (Fc), a novel saponin isolated from Panax notoginseng, effectively counteracts platelet aggregation. Nevertheless, the potential effects and molecular mechanisms of Fc on reendothelialization have yet to be explored. In this study, we present novel findings that show the benefit of Fc in accelerating reendothelialization and alleviating excessive neointimal formation following carotid artery injury in diabetic Sprague–Dawley rats in vivo. Simultaneously, the decreased autophagy of the injured carotid artery in diabetic rats was restored by Fc treatment. Our in vitro results also demonstrated that Fc promoted endothelial cell proliferation and migration under high-glucose treatment by increasing autophagy. In summary, this study supported the notion that Fc could accelerate reendothelialization following vascular injury in diabetic rats by promoting autophagy, suggesting that Fc may exert therapeutic benefits for early endothelial injury and restenosis following intervention in diabetes-associated vascular diseases.

Redox Regulation of Mitochondrial Fission Protein Drp1 by Protein Disulfide Isomerase Limits Endothelial Senescence

In BriefKim et al. demonstrate a molecular link between PDIA1 and Drp1 oxidoreduction, which protects against mitochondrial fragmentation and ROS elevation, limiting endothelial senescence. This study provides insights into restoring endothelial PDIA1 function or targeting Drp1 Cys oxidation as potential therapeutic strategies for treating diabetes-associated vascular and metabolic diseases.

Repeatability and reproducibility of IVAN software measuring retinal vascular caliber

Background Retinal vascular caliber changes can reflect the development status of cardiovascular disease and diabetes-associated vascular diseases, so it is very important to quantitatively measure retinal vascular caliber in the study of systemic diseases and retinal vascular disease.However, the methodology study is rately seen in China within our knowledge. Objective The present study was to investigate the repeatability and reproducibility of IVAN software in measuring retinal vascular caliber. Methods This study was approved by Ethic Committee of Affiliated Hospital of Inner Mongolia Medical University, and written informed consent was obtained from each subject prior to medical examination.A prospectively diagnostic trail was performed.The digitized fundus color photograph centered on the disc from 192 eyes of 96 healthy volunteers were collected in Affiliated Hospital of Inner Mongolia Medical University from January, 2013 to December, 2014, and central retinal arteriolar equivalent (CRAE), central retinal venular equivalent (CRVE) and arteriovenous ratio (AVR) were analyzed by IVAN measurement software.The repeatability and reproducibility of IVAN software for random repeat measurement of retinal vessel caliber from consecutive 85 right eyes of 85 volunteers were evaluation by interobserver and intraobserver measurement with interclass correlation coefficient (ICC). The correlations of measuring results between two observers or two-time measuring were analyzed with Pearson linear correlation analysis.Bland-Altman agreeement analysis was employed to assess the agreeement of the outcomes. Results No significant differences were found in CRAE, CRVE and AVR between the right eyes and the left eyes (t=-1.009, 1.090, -1.259, all at P>0.05). The CRAE, CRVE and AVR values from observer 1 were (145.02±12.94)μm, (400.72±9.12)μm and 0.36±0.03, and those from observer 2 were (145.10±11.86)μm, (401.17±9.85)μm and 0.36±0.03, with no significant differences between observer 1 and observer 2 (t=-0.074, -0.913, 0.116, all at P>0.05). The repeat CRAE, CRVE and AVR values from observer 1 were (145.02±12.94)μm, (400.72±9.12)μm and 0.36±0.03, which were significantly different from the initial values (t=-0.777, -0.048, -0.745, all at P>0.05). In two-time measurements of intra-observer, all ICC were ≥0.738 and showed good correlations (all at r≥0.739). The two measurements of inter-observer, showed good correlations (r≥0.662), with all ICC ≥0.657.Bland-Altman plots showed good agreements in CRAE and CRVE measurement with 95% limits of agreement(LoA) ranged from -18.5 μm to 17.3 μm and -9.8 μm to 9.6 μm in intraobserver, and from -19.3 μm to 20.0 μm and -10.2 μm to 9.0 μm in interobserver, respectively. Conclusions IVAN measurement software yields good repeatability and reproducibility in the quantitative measurement of retinal vascular caliber. Key words: Vascular caliber, retinal; Biometry; Repeatability; Reproducibility; IVAN software

High glucose induces the release of endothelin-1 through the inhibition of hydrogen sulfide production in HUVECs.

Hydrogen sulfide (H(2)S) has recently been identified as an endogenous gaseous signaling molecule. In the vascular system, the formation of H(2)S is catalyzed by cystathionine γ‑lyase (CSE). Previous studies have demonstrated the protective effects of H(2)S on ischemic injury in various types of tissue. However,, little is known about the role of H(2)S in diabetes-associated vascular diseases. Thus, the aim of the present study was to examine the possible role of H(2)S in high glucose-induced vascular dysfunction, and to explore the underlying mechanisms. Human umbilical vein endothelial cells (HUVECs) were isolated from human umbilical veins. The levels of H(2)S following treatment with various levels of glucose were determined and the secretion of endothelin-1 (ET-1) was measured by ELISA. The mRNA and protein expression of CSE in the HUVECs was determined by real-time RT-PCR and western blot analysis, respectively. Treatment with high glucose (25 mmol/l) for 48 h significantly increased the secretion of ET-1 by HUVECs, with the concomitant suppression of H(2)S production and CSE protein expression. The increase in exogenous H(2)S levels through the administration of sodium hydrosulfide (NaHS) attenuated the high glucose-induced downregulation of CSE protein expression, and significantly inhibited the secretion of ET-1. These results suggest that the downregulation of CSE protein expression and the subsequent decrease in H(2)S production play a role in high glucose-induced vascular dysfunction possibly by increasing the secretion of ET-1 by endothelial cells.

Targeting Obesity for the Treatment of Type 2 Diabetes Mellitus

The discovery of diabetes mellitus (simplified as “diabetes”) could be traced back to 1500 B.C. The first detailed description appeared in 1800, but in the last few decades, the prevalence of diabetes increases dramatically. Till present, according to WHO’s report, 247 million people worldwide have been diagonized Diabetes, among which 3.47 million died from diabetes. Thus, WHO projects that diabetes will become the 7th leading cause of death in 2030. The typical feature of diabetes is hyperglycemia as a result of metabolic disorder. As the disease progress, complications develop including macrovascular and microvascular abnormality, leading to multiple organ failure and mortality. Apart from diabetes-associated vascular diseases, numerous studies have documented the association between hyperglycemia and cancer. There are three main types of diabetes: (1) type 1 diabetes mellitus (T1DM) in which pancreatic β cell death by immune attack; (2) type 2 diabetes mellitus (T2DM) in which pancreatic β cells fail to produce sufficient amount of insulin; and (3) gestational diabetes which occurs in pregnant women due to high demand for insulin production. Type 2 DM accounts for 80-90% of diabetes and obesity has been identified as a strong and modifiable risk factor in type 2 DM. In this review, we first provide a general introduction of T2DM in the aspects of diagnosis, pathogenesis and clinical characteristics of T2DM. We will focus on how obesity has the adverse impact on insulin resistance, pancreatic β cell death and dysfunction and the development of T2DM. Next, we will summarize the animal models of T2DM including their advantages and drawbacks when compared to their clinical relevance. Finally, we will summarize the interventions that have been applied to treat obesity and T2DM and the remaining problems.

MiR-21 is Overexpressed in Response to High Glucose and Protects Endothelial Cells from Apoptosis

Diabetes was an increasing public health problem nowadays. Accumulating evidences had shed a light on the involvement of endothelial cell dysfunction in the pathogenesis of diabetes-associated vascular diseases. MiR-21, a multiple-functional miRNA, was evidenced to be involved in endothelial dysfunction, however, the underlying molecular mechanisms were still unknown. In current study, we investigated the intrinsic link between miR-21 and high glucose-induced endothelial dysfunction. We demonstrated that expression of miR-21 was elevated in circulating endothelial progenitor cells from diabetes patients. Further, inhibition of miR-21 markedly enhanced high glucose-induced endothelial cytotoxicity. Furthermore, proteomic profiling was applied to analyze the downstream effectors involved in miR-21-meidated protection of endothelial cells. A total of 31 proteins were positively identified, including Annexin A2, S100A4, SOD2, Thioredoxin and DAXX. Altered expression of these proteins was validated by immunoblot. Finally, mechanistic study showed that miR-21 protected endothelial cell against high glucose-induced endothelial cytotoxicity probably by inhibiting the expression of DAXX. Our findings were considered as a significant step toward a better understanding of diabetes-associated vascular diseases.

Effect of 5-hydroxymethylfurfural derived from processed Cornus officinalis on the prevention of high glucose-induced oxidative stress in human umbilical vein endothelial cells and its mechanism

The aim of this study was to investigate the protective effect of 5-HMF on human umbilical vein endothelial cells (HUVECs) injured by high glucose in vitro, and the mechanism underlying this process. Our results demonstrated that high glucose-induced oxidative stress in HUVECs was mainly mediated through activation of reactive oxygen species (ROS), Jun N-kinase 2/3 (JNK2/3) and plasma interleukin-8 (IL-8), and inactivation of phosphorylated protein kinase B (P-Akt). Treatment of HUVECs with media containing high glucose (4.5%) in the presence of 5-HMF (100, 200 and 400μM) resulted in significant inhibition of high glucose-induced oxidative stress and expression of JNK1 and JNK2/3. Furthermore, 5-HMF rapidly inhibited high glucose-induced activation of IL-8, a downstream activator of P-Akt. Diabetes mellitus can cause a wide variety of vascular complications and high glucose can induce vascular endothelial cell apoptosis. Free radicals are formed disproportionately in diabetes by glucose oxidation. The finding of this study highlights the pharmacological application of 5-HMF for preventing cardiovascular and diabetes mellitus diseases, and provides the theoretical basis for further development of a Cornus officinalis agent for diabetes-associated vascular diseases.

Plasma Endothelial Microparticles and Their Correlation With the Presence of Hypertension and Arterial Stiffness in Patients With Type 2 Diabetes

Microparticles (MPs) are associated with several cardiovascular complications. As multifunction biomarkers, they may contribute to the pathogenesis of diabetes-associated vascular diseases. A total of 39 patients with diabetes and hypertension, 24 patients with diabetes without hypertension, and 20 healthy controls were enrolled. Flow cytometry was applied to detect plasma MPs, including endothelial MPs (EMPs), annexin V+MPs, platelet-derived MPs (PMPs), and leukocyte-derived MPs (LMPs). Brachial ankle pulse wave velocity (baPWV) was also performed in admission. Plasma EMPs, annexin V+MPs, PMPs, and LMPs in diabetics with or without hypertension were higher than those in control patients. Among diabetics, only EMPs in patients with hypertension was higher than in those without hypertension. Correlation analysis showed that systolic blood pressure and mean blood pressure were positively correlated with EMPs. Multivariant analysis demonstrated that EMP was an independent risk factor for the presence of hypertension in diabetics (odds ratio, 2.822; 95% confidence interval, 1.265-6.296; P=.011). Furthermore, baPWV in diabetics with hypertension (1910±355 cm/s) was higher than that in control patients (1441±198 cm/s) and diabetics without hypertension (1727±2 cm/s). Multivariant analysis identified EMP as a potent contributor to the development of impaired artery elasticity in diabetics (odds ratio, 4.401; 95% confidence interval, 1.529-12.673; P=.006). Plasma EMP was associated with the presence of hypertension and impaired arterial stiffness in type 2 diabetes.

PPARγ Ligands Inhibit Hyperglycemia Induced Endothelial Nox‐4 Expression and Oxidative Stress

Hyperglycemia‐induced oxidative stress is implicated in the pathogenesis of diabetes‐associated vascular diseases. We demonstrated that the expression and activity of NADPH oxidase, was increased in the aortas of diabetic, leptin receptor‐deficient mice and that administration of the PPARγ ligand, rosiglitazone (RSG), reduced the expression of several NADPH oxidase subunits to control levels. In this study, we tested the hypothesis that endothelial NADPH oxidases contribute to hyperglycemia‐induced oxidative stress. Human aortic endothelial cells were treated with normal (5 mmol/L) or high (30 mmol/L) glucose concentrations for 24 – 72 hours. Compared to normal, high glucose increased hydrogen peroxide (H2O2) generation measured with Amplex Red and increased mRNA and protein levels of the H2O2‐generating subunit of NADPH oxidase, Nox‐4. Treatment with either the non‐specific, NADPH oxidase inhibitor, diphenyliodonium (10 μmol/L), or RSG (10 μmol/L) attenuated glucose‐stimulated H2O2 generation. These findings suggest that high glucose concentrations can induce increases in the expression and activity of endothelial Nox‐4 that may contribute to vascular oxidative stress and that ligands for PPARγ may represent a novel target to inhibit NADPH oxidase expression and oxidative stress in the vascular endothelium.Supported by: The Atlanta VA Research Service and NIH RO1 (DK074518).

Hyperglycemia upregulates translation of the fibroblast growth factor 2 mRNA in mouse aorta via internal ribosome entry site.

Fibroblast growth factor 2 (FGF-2) is normally synthesized at low levels but is elevated in various pathophysiological conditions including diabetes-associated vascular diseases. FGF-2 expression is regulated translationally through an internal ribosome entry site (IRES) located in its mRNA, which allows a nonclassical cap-independent translation. We addressed the pathophysiological regulation of the IRES in vivo by using a streptozotocin-induced hyperglycemic model known to suppress markedly overall translation. Evaluation of FGF-2 IRES-dependent translation was performed with transgenic mice expressing dual luciferase bicistronic mRNA containing the FGF-2 IRES. FGF-2 IRES-dependent reporter activity increased 240% of control in the diabetic aorta although the reporter mRNA levels significantly decreased. Expression of endogenous FGF-2 protein in the aorta closely correlated with the IRES activity but not with FGF-2 mRNA levels. Moreover, the biosynthesis of endogenous FGF-2 protein was stimulated in an IRES-dependent manner by high glucose that significantly suppressed global protein synthesis in aortic smooth muscle cells from the transgenic mice. These results suggest that IRES-dependent translational regulation could play a pathological role in FGF-2 expression in vivo, especially in the cardiovascular consequences of diabetes.