Prognostic value of endothelial dysfunction in type 1 diabetes mellitus

Sex-Dependent Impairment of Endothelium-Dependent Relaxation in Aorta of Mice with Overexpression of Hyaluronan in Tunica Media

Diabetic macroangiopathy is characterized by increased extracellular matrix deposition, including excessive hyaluronan accumulation, vessel thickening and stiffness, and endothelial dysfunction in large arteries. We hypothesized that the overexpression of hyaluronan in the tunica media also led to endothelial cell (EC) dysfunction. To address this hypothesis, we investigated the following in the aortas of mice with excessive hyaluronan accumulation in the tunica media (HAS-2) and wild-type mice: EC dysfunction via myograph studies, nitric oxide (NO) bioavailability via diaminofluorescence, superoxide formation via dihydroethidium fluorescence, and the distances between ECs via stereological methods. EC dysfunction, characterized by blunted relaxations in response to acetylcholine and decreased NO bioavailability, was found in the aortas of male HAS-2 mice, while it was unaltered in the aortas of female HAS-2 mice. Superoxide levels increased and extracellular superoxide dismutase (ecSOD) expression decreased in the aortas of male and female HAS-2 mice. The EC-EC distances and LDL receptor expression were markedly increased in the HAS-2 aortas of male mice. Our findings suggest hyaluronan increases oxidative stress in the vascular wall and that together with increased EC distance, it is associated with a sex-specific decrease in NO levels and endothelial dysfunction in the aorta of male HAS-2 transgenic mice.

The Role of Polyphenol in Modulating Associated Genes in Diabetes-Induced Vascular Disorders

Diabetes-induced vascular disorder is considered one of the deadly risk factors among diabetic patients that are caused by persistent hyperglycemia that eventually leads to cardiovascular diseases. Elevated reactive oxygen species (ROS) due to high blood glucose levels activate signaling pathways such as AGE/RAGE, PKC, polyol, and hexosamine pathways. The activated signaling pathway triggers oxidative stress, inflammation, and apoptosis which later lead to vascular dysfunction induced by diabetes. Polyphenol is a bioactive compound that can be found abundantly in plants such as vegetables, fruits, whole grains, and nuts. This compound exerts therapeutic effects in alleviating diabetes-induced vascular disorder, mainly due to its potential as an anti-oxidative, anti-inflammatory, and anti-apoptotic agent. In this review, we sought to summarize the recent discovery of polyphenol treatments in modulating associated genes involved in the progression of diabetes-induced vascular disorder.

Omega-3 fatty acids coordinate glucose and lipid metabolism in diabetic patients

Omega 3 polyunsaturated fatty acids (n-3 PUFA) are known to have beneficial effects on cardiovascular and metabolic health. However, whether different sources of n-3 PUFA, for instance fatty fish vs vegetable oils, could elicit different effects on glucose and lipid metabolism, remains to be determined. Herein we examine recent findings showing that while a plant-based n-3 PUFA supplementation for six months can reduce fasting blood glucose, marine-based n-3 PUFA can instead reduce serum levels of triglycerides. We also discuss the potential molecular mechanisms that could underlie these different effects on the regulation of glycolipid metabolism.

Decreased Flow-Mediated Dilatation in Children With Type 1 Diabetes: A Systematic Review and Meta-Analysis

Type 1 diabetes (T1DM) is a strong risk factor for the development of cardiovascular disease. Flow-mediated dilatation (FMD) is an early noninvasive marker of endothelial function and it predicts future cardiovascular disease. However, the changes in FMD among T1DM children are still controversial. The present meta-analysis aimed to investigate whether FMD is impaired in children with T1DM. PubMed, EMBASE, Cochrane library, and Web of Science were searched for studies comparing FMD in children with T1DM and healthy controls. The Newcastle-Ottawa quality assessment scale for case-control studies was used to assess study quality. Data were pooled using a random effects models to obtain the weighted mean differences (WMD) in FMD and 95% CIs. Overall, 19 studies with 1245 patients and 872 healthy controls were included in this meta-analysis. Children with T1DM had significantly lower FMDs compared with healthy controls (WMD: -2.58; 95% CI: -3.36 to -1.81; P < .001). Meta-regression analysis revealed that low-density lipoprotein cholesterol levels impacted the observed difference in FMD between T1DM and healthy children. This meta-analysis showed that T1DM children have impaired endothelial function, which indicates they are at higher risk of developing cardiovascular disease in later life.

Association of Exosomal miR-34a with Markers of Dyslipidemia and Endothelial Dysfunction in Children and Adolescents with T1DM

OBJECTIVE

Dyslipidemia and endothelial dysfunction are common disorders and major causative factors for atherosclerosis in patients with type 1 diabetes mellitus (T1DM). However, their pathophysiology in young patients with T1DM is still under evaluated. We aimed, for the first time, to assess the expression of exosomal micro-RNA 34a (miR-34a) in serum of children and adolescents with T1DM and correlate this expression with markers of dyslipidemia and endothelial dysfunction.

METHODS

The study included 120 T1DM patients and 100 control subjects. Assessment of miR-34a was performed using quantitative real-time polymerase chain reaction. Lipid profile was assessed on an automated analyzer and serum endoglin and intracellular adhesion molecule (ICAM) concentrations were measured using immunometric methods.

RESULTS

Relative expression of miR-34a and serum endoglin and ICAM concentrations were higher in patients than controls (p=0.001) and in patients with dyslipidemia (42 patients) compared to patients without dyslipidemia (78 patients) (p=0.01). Linear regression analysis revealed a strong independent association between exosomal miR-34a expression and total cholesterol, low-density lipoprotein, serum endoglin and serum ICAM after adjustment for other cofactors. The utility of miR-34a as an indicator for associated dyslipidemia was tested using receiver operator characteristic curve analysis which revealed area under the curve: 0.73 with confidence interval: 0.63-0.83 and p=0.001.

CONCLUSION

This was the first study to show the altered expression of exosomal miR-34a among children and adolescents with T1DM. Moreover, association of miR-34a with markers of dyslipidemia and endothelial dysfunction was identified, suggesting that it could play a role in regulation of lipid metabolism and endothelial function in T1DM.

High levels of endothelial and platelet microvesicles in patients with type 1 diabetes irrespective of microvascular complications

INTRODUCTION

Patients with type 1 diabetes have high risk of developing microvascular complications, and microangiopathy contributes to premature cardiovascular disease in this population. The role that microvesicles (MVs) may play in the development of microangiopathy in type 1 diabetes remains unclear.

MATERIALS AND METHODS

Plasma levels of endothelial MVs (EMVs) and platelet MVs (PMVs) in 130 patients with type 1 diabetes without microangiopathy, 106 patients with microangiopathy and 100 matched healthy controls were analyzed using flow cytometry. MV expression of procoagulant phosphatidylserine (PS) and proinflammatory high mobility group box-1 protein (HMGB1) was also assessed.

RESULTS

Patients with type 1 diabetes had markedly elevated levels of EMVs and PS+ EMVs as well as PMVs and PS+ PMVs compared to healthy controls (p < .001 for all). Furthermore, HMGB1+ EMVs and HMGB1+ PMVs were significantly increased in patients (p < .001 for all). After adjusting for potential confounders, there were no clear differences between patients with or without microvascular complications for any of the MV parameters.

CONCLUSION

Type 1 diabetes is a prothrombotic and proinflammatory disease state that, regardless of the presence of clinical microangiopathy, is associated with elevated levels of plasma MVs, in particular those of an endothelial origin. We have for the first time demonstrated that patients with type 1 diabetes have higher levels of HMGB1+ MVs. HMGB1 is an alarmin with potent proinflammatory effects that drive endothelial dysfunction, and it would therefore be of interest to further study the role of HMGB1+ MVs in the development of macrovascular complications in type 1 diabetes.

The High-Resolution Three-Dimensional Magnetic Detector System 3D-Magma Accurately Measures Gastric and Small Bowel Motility in People with Type 2 Diabetes with Neuropathy

Gastroparesis is an important complication of diabetes. Motility disorders are underdiagnosed and can lead to unexplained hypoglycemia. Currently diagnostic options are limited. All established methods harbor certain disadvantages. The 3D-MAGMA system is capable of reliably measuring gastric and small intestinal motility. The aim of the current study was to determine if 3D-MAGMA is able to detect changes in intestinal motility in people with type 2 diabetes. 18 healthy volunteers and 19 people with type 2 diabetes underwent motility testing by 3D-MAGMA. In the control group the retention time in the stomach was 33.0 [min] compared to 75.3 [min] in the diabetes group. The median time in the duodenum was 12.7 [min] compared to 8.1 [min]. The time for the first 50 cm of the jejunum was 29.9 [min] compared to 28.2 [min]. Discussion and conclusion: 3D-MAGMA is able to detect changes in intestinal motility. Its clinical value might be useful in patients with fluctuating blood glucose levels and unexplained hypoglycemic episodes.

Expression of miR-217 and HIF-1α/VEGF pathway in patients with diabetic foot ulcer and its effect on angiogenesis of diabetic foot ulcer rats

OBJECTIVE

To investigate the expression of miR-217 and HIF-1α/VEGF pathway in patients with diabetic foot ulcer (DFU) and its effect on angiogenesis in DFU rats.

METHODS

The serum levels of miR-217, HIF-1α and VEGF were detected in DFU and simple diabetes mellitus (DM) patients, and healthy controls. DFU rat models were established and treated with miR-217 inhibitors and/or HIF-1α siRNA. The ulcer healing of DFU rats was observed. Besides, ELISA method was performed to detect the serum level of HIF-1α, VEGF and inflammatory factors, immunohistochemical (IHC) method to test the micro-vessel density (MVD), as well as qRT-PCR and Western blot to determine expressions of miR-217, HIF-1α, VEGF, VEGFR2, eNOS, MMP-2, and MMP-9 in tissues.

RESULTS

The serum levels of miR-217 were up-regulated while HIF-1α and VEGF were down-regulated in DFU patients and rats when compared with DM and healthy controls (all P < 0.05). Dual-luciferase reporter gene assay confirmed that HIF-1α was the direct target gene of miR-217. DFU rats treated with miR-217 inhibitors had decreased foot ulcer area and accelerated ulcer healing, with significantly reduced inflammatory factors (IL-1β, TNF-α and IL-6), as well as elevated HIF-1α and VEGF (all P < 0.05); meanwhile, they remarkably increased the MVD in foot dorsum wound tissues and the protein expressions of HIF-1α, VEGF, VEGFR2, eNOS, MMP-2, and MMP-9 (all P < 0.05).

CONCLUSION

Inhibiting miR-217 could up-regulate HIF-1α/VEGF pathway to promote angiogenesis and ameliorate inflammation of DFU rats, thereby effectively advancing the healing of ulcerated area.

Endothelial and left ventricular diastolic function in young adults exposed to tobacco

Smoking is associated with endothelial and left ventricular diastolic disfunction. We aimed to determine the endothelial and diastolic function in young adults exposed to tobacco smoke and the effects of acute exposure to it. Smokers were considered as cases and non-smokers as controls. Brachial artery diameter, brachial artery flow velocity, and echocardiographic variables were measured. Mean age of the participants was 21 years. Smokers showed significant endothelial dysfunction compared with non-smokers. Arterial dilation mediated by the endothelium was significantly higher in non-smokers than in smokers (p = 0.005). Non-endothelium-mediated arterial dilation was significantly impaired in smokers compared with non-smokers (p = 0.02). After reactive hyperaemia, there was a significant increase in blood flow in non-smokers (61%) compared with that in smokers (29%). Acute cigarette exposure showed a trend towards left ventricle diastolic disfunction in smokers. Left atrium diameter was significantly higher in smokers than in non-smokers. After acute exposure to cigarette smoke, arterial dilation and brachial flow velocity were lower than those achieved in the abstinence phase (p = 0.005). We concluded that endothelium-dependent arterial dilation is impaired in young smokers and it worsens even after acute exposure to cigarette smoke.

Organ-on-chips made of blood: endothelial progenitor cells from blood reconstitute vascular thromboinflammation in vessel-chips

Development of therapeutic approaches to treat vascular dysfunction and thrombosis at disease- and patient-specific levels is an exciting proposed direction in biomedical research. However, this cannot be achieved with animal preclinical models alone, and new in vitro techniques, like human organ-on-chips, currently lack inclusion of easily obtainable and phenotypically-similar human cell sources. Therefore, there is an unmet need to identify sources of patient primary cells and apply them in organ-on-chips to increase personalized mechanistic understanding of diseases and to assess drugs. In this study, we provide a proof-of-feasibility of utilizing blood outgrowth endothelial cells (BOECs) as a disease-specific primary cell source to analyze vascular inflammation and thrombosis in vascular organ-chips or "vessel-chips". These blood-derived BOECs express several factors that confirm their endothelial identity. The vessel-chips are cultured with BOECs from healthy or diabetic patients and form an intact 3D endothelial lumen. Inflammation of the BOEC endothelium with exogenous cytokines reveals vascular dysfunction and thrombosis in vitro similar to in vivo observations. Interestingly, our study with vessel-chips also reveals that unstimulated BOECs of type 1 diabetic pigs show phenotypic behavior of the disease - high vascular dysfunction and thrombogenicity - when compared to control BOECs or normal primary endothelial cells. These results demonstrate the potential of organ-on-chips made from autologous endothelial cells obtained from blood in modeling vascular pathologies and therapeutic outcomes at a disease and patient-specific level.

Advanced Glycation End-Products and Hyperglycemia Increase Angiopoietin-2 Production by Impairing Angiopoietin-1-Tie-2 System

The angiopoietin-Tie-2 system plays a crucial role in the maintenance of endothelial integrity. Hyperglycemia and advanced glycation end-products (AGEs) are involved in endothelial cell dysfunction responsible of the pathogenesis of microvascular complications of diabetes. Here, we investigated whether glycated serum (GS) or hyperglycemia (HG) affect the angiopoietin-Tie-2 system in the microvascular endothelial cells HMEC-1. We found that culture for 5 days in the presence of AGEs and HG (alone or in combination) decreased cell proliferation, increased reactive oxygen species (ROS) production, and reduced ratio between the oxidized and the reduced form of glutathione. Since angiopoietin-1 (Ang-1) signaling regulates angiopoietin-2 (Ang-2) expression through inactivation of the forkhead transcription factor FoxO1, we investigated intracellular signaling of Ang-1 and expression of Ang-2. HG and AGEs reduced phosphorylation of Akt and abrogated phosphorylation of FoxO1 induced by Ang-1 without affecting neither Tie-2 expression nor its activation. Furthermore, AGEs and/or HG induced nuclear translocation of FoxO1 and increased Ang-2 production. In conclusion, we demonstrated that both hyperglycemia and AGEs affect the angiopoietin-Tie-2 system by impairing Ang-1/Tie-2 signaling and by increasing Ang-2 expression. These results suggest that therapeutic strategies useful in preventing or delaying the onset of diabetic vascular complications should be aimed to preserve Ang-1 signaling.

Associations between endothelial dysfunction and clinical and laboratory parameters in children and adolescents with sickle cell anemia

Background

Hematological changes can drive damage of endothelial cells, which potentially lead to an early endothelial dysfunction in patients with sickle cell anemia (SCA). An association may exist between endothelial dysfunction and several clinical manifestations of SCA. The present study aims to evaluate the links between changes in endothelial function and clinical and laboratory parameters in children and adolescents with SCA.

Methods

This study included 40 children and adolescents with stable SCA as well as 25 healthy children; aged 6–18 years. All study subjects were evaluated for endothelial function using Doppler ultrasonography. In addition, a number of laboratory assays were performed, including reticulocyte and leukocyte counts as well as measurement of circulating levels of total bilirubin, C-reactive protein (CRP), glucose, lipoproteins and peripheral oxyhemoglobin saturation. These parameters were also compared between SCA patients who were undertaking hydroxyurea (HU) and those who were not.

Results

Flow-mediated vasodilation (FMD) values were found to be reduced in SCA patients compared with those detected in healthy controls. SCA individuals with lower FMD values exhibited higher number of hospital admissions due to vaso-occlusive events. Additional analyses revealed that patients who had decreased FMD values exhibited higher odds of acute chest syndrome (ACS) episodes. A preliminary analysis with limited number of individuals failed to demonstrate significant differences in FMD values between SCA individuals who were treated with HU and those who were not.

Conclusions

Children and adolescents with SCA exhibit impaired endothelial function. Reductions in FMD values are associated with ACS. These findings underline the potential use of FMD as screening strategy of SCA patients with severe prognosis at early stages.

Administration of Selenium Decreases Lipid Peroxidation and Increases Vascular Endothelial Growth Factor in Streptozotocin Induced Diabetes Mellitus

Objective

The imbalance in oxidant/antioxidant status plays a pivotal role in diabetes mellitus (DM). Selenium is a integral component of the antioxidant enzyme glutathione peroxidase. Se treatment induces angiogenesis and improves endothelial function through increased expression of vascular endothelial growth factor (VEGF). The aim of this study is to investigate the effect of selenium on oxidative stress, VEGF, and endothelin 1 (ET1) in a DM rat model.

Materials and Methods

We performed an experimental animal study with 64 adult male Wistar-Albino rats. Rats were divided into the following groups (n=8): control (C)7, C21, C+sodium selenite (Se)7, and C+Se21 (control rats), and DM7, DM21, DM+Se7, and DM+Se21 (diabetic rats). Diabetes was induced by 2-deoxy-2-(3-methyl-3-nitrosoureido)- D-glucopyranose [streptozotocin (STZ)]. Three weeks after STZ, DM+Se7 rats received intraperitoneal (i.p.) injections of 0.4 mg/kg Se for 7 days. The DM+Se21 rats received these injections for 21 days. The same dose/duration of Se was administered to the C+Se7 and C+Se21 groups. The remaining rats (C7, C21, DM7, DM21) received physi- ologic saline injections for 7 or 21 days. Ferric reducing antioxidant power (FRAP), malon- dialdehyde (MDA), advanced oxidation protein products (AOPP), and endothelial function markers (VEGF and ET1) in plasma samples were measured.

Results

Diabetic rats (DM7 and DM21) had significantly increased plasma FRAP (P=0.002, P=0.001), AOPP (P=0.024, P=0.01), MDA (P=0.004, P=0.001), and ET1 (P=0.028, P=0.003) levels compared with C7 and C21 control rats. VEGF (P=0.02, P=0.01) significantly decreased in DM7 and DM21 diabetic rats compared with their controls (C7, C21). Se administration reversed the increased MDA and decreased VEGF levels, and lowered plasma glucose levels in the DM+Se7 and DM+Se21 diabetic groups compared with diabetic rats (DM7, DM21). We observed positive correlations between FRAP-AOPP (r=0.460), FRAP-ET1 (r=0.510), AOPP-MDA (r=0.270), and AOPP-ET1 (r=0.407), and a negative correlation between MDA-VEGF (r=-0.314).

Conclusion

We observed accentuated oxidative stress and impaired endothelial function in diabetes. Se treatment reduced lipid peroxidation and hyperglycemia. Se probably improved endothelial dysfunction in diabetic rats because of the increased VEGF levels.

A Shift in ApoM/S1P Between HDL-Particles in Women With Type 1 Diabetes Mellitus Is Associated With Impaired Anti-Inflammatory Effects of the ApoM/S1P Complex

Objective—

Type 1 diabetes mellitus (T1D) patients have an increased risk of cardiovascular disease despite high levels of high-density lipoproteins (HDL). Apolipoprotein M (apoM) and its ligand sphingosine 1-phospate (S1P) exert many of the anti-inflammatory effects of HDL. We investigated whether apoM and S1P are altered in T1D and whether apoM and S1P are important for HDL functionality in T1D.

Approach and Results—

ApoM and S1P were quantified in plasma from 42 healthy controls and 89 T1D patients. HDL was isolated from plasma and separated into dense, medium-dense, and light HDL by ultracentrifugation. Primary human aortic endothelial cells were challenged with tumor necrosis factor-α in the presence or absence of isolated HDL. Proinflammatory adhesion molecules E-selectin and vascular cellular adhesion molecule-1 were quantified by flow cytometry. Activation of the S1P 1 - receptor was evaluated by analyzing downstream signaling targets and receptor internalization. There were no differences in plasma levels of apoM and S1P between controls and T1D patients, but the apoM/S1P complexes were shifted from dense to light HDL particles in T1D. ApoM/S1P in light HDL particles from women were less efficient in inhibiting expression of vascular cellular adhesion molecule-1 than apoM/S1P in denser particles. The light HDL particles were unable to activate Akt, whereas all HDL subfractions were equally efficient in activating Erk and receptor internalization.

Conclusions—

ApoM/S1P in light HDL particles were inefficient in inhibiting tumor necrosis factor-α–induced vascular cellular adhesion molecule-1 expression in contrast to apoM/S1P in denser HDL particles. T1D patients have a higher proportion of light particles and hence more dysfunctional HDL, which could contribute to the increased cardiovascular disease risk associated with T1D.

Blocking 5-HT2 receptor restores cardiovascular disorders in type 1 experimental diabetes

This study aimed to determine whether the serotonergic modulation, through selective 5-HT₂ receptor blockade, restores cardiovascular disturbances in type 1 diabetic rats. Diabetes was induced by alloxan (150 mg/kg, s.c.) and maintained for 4 weeks. 5-HT₂ receptor was blocked by sarpogrelate (30 mg/kg.day; 14 days; p.o.). Systolic blood pressure (SBP), heart rate (HR), glycaemia and body weight (BW) were monitored periodically. Animals were sacrificed at the end of the study and the heart, right kidney and thoracic aorta were removed; plasma samples were also obtained. Left ventricular hypertrophy index (LVH) and renal hypertrophy index (RH) were determined. Vascular function was studied in aorta rings; additionally, superoxide anion (O₂•⁻) production (by lucigenin-enhanced chemiluminescence) and lipid peroxidation (by thiobarbituric acid reactive substances assay) were measured. Neither alloxan nor sarpogrelate treatments altered HR, LVH or endothelium-independent relaxation. SBP, glycaemia, BW, RH, O₂•⁻ production and lipid peroxidation were significantly altered in diabetic animals compared with controls. Sarpogrelate treatment considerably decreased SBP, RH, O₂•⁻ production and lipid peroxidation. Endothelium-dependent relaxation was severely reduced in diabetic animal aortas compared to controls; sarpogrelate treatment markedly improved it. Our outcomes show that selectively blocking 5-HT₂ receptors has beneficial effects on impaired cardiovascular parameters in diabetes.

The simultaneous control of hyperglycemia and GLP-1 infusion normalize endothelial function in type 1 diabetes

BACKGROUND

To test the effect of normoglycemia and glucagon-like peptide-1 (GLP-1), alone or in combination, on the possible normalization of endothelial function in type 1 diabetes.

METHODS

Fifteen people with type 1 diabetes participated in three experiments: reaching and maintaining normoglycemia for 4h; reaching and maintaining hyperglycemia plus GLP-1 infusion for 4h; and reaching and maintaining normoglycemia for 4h with simultaneous infusion of GLP-1.

RESULTS

Both normoglycemia and GLP-1 infusion restored endothelial function and decreased and plasma 8-iso prostaglandin F2α levels. However, only the combination of normoglycemia and GLP-1 was able to normalize endothelial function.

CONCLUSIONS

This study confirms that long-lasting hyperglycemia in type 1 diabetes induces a permanent alteration which contributes to maintaining endothelial dysfunction even when glycemia is normalized, and that in the presence of normoglycemia, GLP-1 can contribute to normalizing endothelial function.

Hypochlorite-Modified Albumin Upregulates ICAM-1 Expression via a MAPK-NF-κB Signaling Cascade: Protective Effects of Apocynin

Hypochlorite-modified albumin (HOCl-alb) has been linked to endothelial dysfunction, which plays an important role in the development of hypertension, diabetes, and chronic kidney disease. However, whether HOCl-alb induces endothelial dysfunction via vascular inflammation and whether a signaling pathway is involved are unknown and have not been investigated. HOCl-alb was found to upregulate ICAM-1 expression in human umbilical vein endothelial cells (HUVECs) in a time- and dose-dependent manner. HOCl-alb time-dependently phosphorylated ERK1/2 and p38(MAPK). HOCl-alb also activated NF-κB. ICAM-1 expression was dose-dependently inhibited by U0126 (a specific inhibitor of MEK1/2, a signal upstream from ERK1/2), SB203580 (a specific inhibitor of p38(MAPK)), and SN50 (a specific inhibitor of NF-κB). U0126 and SB203580 both counteracted the activation of NF-κB, whereas the phosphorylation of ERK1/2 and p38(MAPK) was not blocked by SN50. ERK1/2 phosphorylation was blocked by U0126 but not by SB203580, and p38(MAPK) activity was reduced by SB203580 but not by U0126. Apocynin, a specific NADPH oxidase (NOX) inhibitor, inhibited ICAM-1 expression and the activity of ERK1/2, p38(MAPK), and NF-κB. These results indicate that HOCl-alb-induced ICAM-1 expression is caused by the activation of a redox-sensitive intracellular signal cascade involving ERK1/2 and p38(MAPK), culminating in the activation of NF-κB and involving NOXs among the upstream signals.

SERUM LEVELS OF ENDOTHELIAL MONOCYTE ACTIVATING PEPTIDE II IN TYPE 1 DIABETES

Was investigated serum level of endothelial monocyte activating peptide II (EMAP-II) and endothelium-dependent dilatation in type 1 diabetes and possible relation between those. We found an increase serum level of EMAP-II and decrease of endothelium-dependent dilatation in type 1 diabetes. It was significant correlation between EMAP-II and HbAc1, blood glucose, total cholesterol, LDL, triglycerides and inverse correlation between EMAP-II and HDL, endotheliumdependent dilatation. The revealed change of EMAP-II serum level reflects an endothelial dysfunction in type 1 diabetes, alteration of carbohydrate and lipid metabolism could influence of this pathway.

Exogenous Angiotensin I Metabolism in Aorta Isolated from Streptozotocin Treated Diabetic Rats

Purpose. Products of angiotensin (ANG) I metabolism may predispose to vascular complications of diabetes mellitus. Methods. Diabetes was induced with streptozotocin (75 mg/kg i.p.). Rat aorta fragments, isolated 4 weeks later, were pretreated with perindoprilat (3 μM), thiorphan (3 μM), or vehicle and incubated for 15 minutes with ANG I (1 μM). Products of ANG I metabolism through classical (ANG II, ANG III, and ANG IV) and alternative (ANG (1-9), ANG (1-7), and ANG (1-5)) pathways were measured in the buffer, using liquid chromatography-mass spectrometry. Results. Incubation with ANG I resulted in higher concentration of ANG II (P = 0.02, vehicle pretreatment) and lower of ANG (1-9) (P = 0.048, perindoprilat pretreatment) in diabetes. Preference for the classical pathway is suggested by higher ANG III/ANG (1-7) ratios in vehicle (P = 0.03), perindoprilat (P = 0.02), and thiorphan pretreated (P = 0.02) diabetic rat. Within the classical pathway, ratios of ANG IV/ANG II (P = 0.01) and of ANG IV/ANG III (P = 0.049), but not of ANG III/ANG II are lower in diabetes. Conclusions. Diabetes in rats led to preference toward deleterious (ANG II, ANG III) over protective (ANG IV, ANG (1-9), and ANG (1-7)) ANG I metabolites.

Enhanced A2A adenosine receptor-mediated increase in coronary flow in type I diabetic mice

Adenosine A2A receptor (A2AAR) activation plays a major role in the regulation of coronary flow (CF). Recent studies from our laboratory and others have suggested that A2AAR expression and/or signaling is altered in disease conditions. However, the coronary response to AR activation, in particular A2AAR, in diabetes is not fully understood. In this study, we use an STZ mouse model of type 1 diabetes (T1D) to look at CF responses to the nonspecific AR agonist NECA and the A2AAR specific agonist CGS 21680 in-vivo and ex-vivo. Using immunofluorescence, we also explored the effect of diabetes on A2AAR expression in coronary arteries. NECA mediated increase in CF was significantly increased in hearts isolated from STZ-induced diabetic mice. In addition, both in in-vivo and ex-vivo responses to A2AAR activation using CGS 21680 were significantly higher in diabetic mice when compared to their controls. Immunohistochemistry showed an upregulation of A2AAR in both coronary smooth muscle and endothelial cells (~160% and ~140%, respectively). Our data suggest that diabetes resulted in an increased A2AAR expression in coronary arteries which resulted in enhanced A2AAR-mediated increase in CF observed in diabetic hearts. This is the first report implying that A2AAR has a role in the regulation of CF in diabetes, supporting recent studies suggesting that the use of adenosine and its A2A selective agonist (regadenoson, Lexiscan®) may not be appropriate for the detection of coronary artery diseases in T1D and the estimation of coronary reserve.

Diabetes and ageing-induced vascular inflammation

Diabetes and the ageing process independently increase the risk for cardiovascular disease (CVD). Since incidence of diabetes increases as people get older, the diabetic older adults represent the largest population of diabetic subjects. This group of patients would potentially be threatened by the development of CVD related to both ageing and diabetes. The relationship between CVD, ageing and diabetes is explained by the negative impact of these conditions on vascular function. Functional and clinical evidence supports the role of vascular inflammation induced by the ageing process and by diabetes in vascular impairment and CVD. Inflammatory mechanisms in both aged and diabetic vasculature include pro-inflammatory cytokines, vascular hyperactivation of nuclear factor-кB, increased expression of cyclooxygenase and inducible nitric oxide synthase, imbalanced expression of pro/anti-inflammatory microRNAs, and dysfunctional stress-response systems (sirtuins, Nrf2). In contrast, there are scarce data regarding the interaction of these mechanisms when ageing and diabetes co-exist and its impact on vascular function. Older diabetic animals and humans display higher vascular impairment and CVD risk than those either aged or diabetic, suggesting that chronic low-grade inflammation in ageing creates a vascular environment favouring the mechanisms of vascular damage driven by diabetes. Further research is needed to determine the specific inflammatory mechanisms responsible for exacerbated vascular impairment in older diabetic subjects in order to design effective therapeutic interventions to minimize the impact of vascular inflammation. This would help to prevent or delay CVD and the specific clinical manifestations (cognitive decline, frailty and disability) promoted by diabetes-induced vascular impairment in the elderly.

Advanced glycation end products upregulate angiopoietin-like protein 4 expression by activating the renin-angiotensin system in endothelial cells

The aim of the present study was to investigate the effects of advanced glycation end products (AGEs) on the expression of angiopoietin-like protein 4 (ANGPTL4) and the mechanisms of the effects in endothelial cells. Endothelial cells were incubated with various concentrations of AGEs for 24 h and the expression of ANGPTL4 was detected by quantitative polymerase chain reaction and western blot analysis. The concentration of angiotensin II (Ang II) in conditioned media and cell lysates was measured by enzyme-linked immunosorbent assays. Fluorescein isothiocyanate-labeled dextran filtration assays and transendothelial electrical resistance were performed to evaluate endothelial permeability. AGEs (80 µg/ml) increased the expression of ANGPTL4 and the levels of Ang II (P<0.05). Incubation with AGEs also resulted in a significant increase in endothelial permeability (P<0.05). However, pretreatment with the Ang II receptor blocker losartan (10^-5 M) reduced the effects of AGEs (P<0.05). AGEs upregulated the expression of ANGPTL4 by activating a local renin-angiotensin system in endothelial cells. This may be a new mechanism by which AGEs increase endothelial permeability.

Are reactive oxygen species still the basis for diabetic complications?

Despite the wealth of pre-clinical support for a role for reactive oxygen and nitrogen species (ROS/RNS) in the aetiology of diabetic complications, enthusiasm for antioxidant therapeutic approaches has been dampened by less favourable outcomes in large clinical trials. This has necessitated a re-evaluation of pre-clinical evidence and a more rational approach to antioxidant therapy. The present review considers current evidence, from both pre-clinical and clinical studies, to address the benefits of antioxidant therapy. The main focus of the present review is on the effects of direct targeting of ROS-producing enzymes, the bolstering of antioxidant defences and mechanisms to improve nitric oxide availability. Current evidence suggests that a more nuanced approach to antioxidant therapy is more likely to yield positive reductions in end-organ injury, with considerations required for the types of ROS/RNS involved, the timing and dosage of antioxidant therapy, and the selective targeting of cell populations. This is likely to influence future strategies to lessen the burden of diabetic complications such as diabetes-associated atherosclerosis, diabetic nephropathy and diabetic retinopathy.

Functional and morphological changes in endocrine pancreas following cola drink consumption in rats

Aim

We report the effects of long-term cola beverage drinking on glucose homeostasis, endocrine pancreas function and morphology in rats.

Methods

Wistar rats drank: water (group W), regular cola beverage (group C, sucrose sweetened) or “light” cola beverage (group L, artificially sweetened). After 6 months, 50% of the animals in each group were euthanized and the remaining animals consumed water for the next 6 months when euthanasia was performed. Biochemical assays, insulinemia determination, estimation of insulin resistance (HOMA-IR), morphometry and immunohistochemistry evaluations were performed in pancreas.

Results

Hyperglycemia (16%, p<0.05), CoQ₁₀ (coenzyme-Q₁₀) decrease (−52%,p<0.01), strong hypertriglyceridemia (2.8-fold, p<0.01), hyperinsulinemia (2.4 fold, p<0.005) and HOMA-IR increase (2.7 fold, p<0.01) were observed in C. Group C showed a decrease in number of α cells (−42%, p<0.01) and β cells (−58%, p<0.001) and a moderate increase in α cells’ size after wash-out (+14%, p<0.001). Group L showed reduction in β cells’ size (−9%, p<0.001) and only after wash-out (L₁₂) a 19% increase in size (p<0.0001) with 35% decrease in number of α cells (p<0.01). Groups C and L showed increase in α/β-cell ratio which was irreversible only in C (α/β = +38% in C₆,+30% in C₁₂, p<0.001vs.W₆). Regular cola induced a striking increase in the cytoplasmic expression of Trx1 (Thioredoxin-1) (2.25-fold in C₆ vs. W₆; 2.7-fold in C₁₂ vs. W_12, p<0.0001) and Prx2 (Peroxiredoxin-2) (3-fold in C₆ vs. W₆; 2-fold in C₁₂ vs. W_12, p<0.0001). Light cola induced increase in Trx1 (3-fold) and Prx2 (2-fold) after wash-out (p<0.0001, L₁₂ vs. W₁₂).

Conclusion

Glucotoxicity may contribute to the loss of β cell function with depletion of insulin content. Oxidative stress, suggested by increased expression of thioredoxins and low circulating levels of CoQ₁₀, may follow sustained hyperglycemia. A likely similar panorama may result from the effects of artificially sweetened cola though via other downstream routes.