Abstract 378: Red Blood Cells From Patients With Type 2 Diabetes Induce Endothelial Dysfunction Through Up-Regulation of Arginase I

2017 ◽  
Vol 37 (suppl_1) ◽  
Author(s):  
Zhichao Zhou ◽  
Ali Mahdi ◽  
Yahor Tratsiakovich ◽  
Oskar Kövamees ◽  
Jiangning Yang ◽  
...  

We previously showed that increased arginase activity is a key mechanism for endothelial dysfunction in patients with type 2 diabetes mellitus (T2DM) thereby arginase inhibition improves endothelial function. Recently, we demonstrated a crucial role of red blood cells (RBCs) in control of cardiac function via an arginase-dependent regulation of nitric oxide export from RBCs, suggesting a direct interaction of RBCs with cardiovascular function. Considering an increase in arginase activity in T2DM, we hypothesized that RBCs induce endothelial dysfunction in T2DM via up-regulated arginase I. Healthy rat aortas were incubated with RBCs from patients with T2DM (T2DM-RBCs) and age-matched healthy subjects (H-RBCs) for 18 h in the absence and presence of the arginase inhibition or scavenging of reactive oxygen/nitrogen species (ROS/RNS). Following the incubation, endothelium-dependent and -independent relaxations (EDR and EIR) were determined using wire myograph. Human internal mammary arteries (IMAs) obtained from non-diabetic patients who underwent cardiac surgery were also incubated with RBCs for functional evaluation. Arginase activity and protein expression were determined in RBCs. EDR was impaired in vessels incubated with T2DM-RBCs (Emax: 43.2±3.0% in aortas, n=8; 32.3±2.7% in IMAs, n=3) but not H-RBCs (Emax: 74.3±3.4% in aortas; 71.5±5.1% in IMAs) in comparison with buffer (Emax: 74.4±2.3% in aortas; 73.1±5.0% in IMAs; P<0.01 vs. T2DM-RBCs). EIR was not affected by T2DM-RBCs. The impairment in EDR in rat aortas was fully reversed by inhibition of arginase, ROS and RNS in RBCs. Arginase activity was significantly elevated in T2DM-RBCs. The increased arginase activity was attributed to arginase I, as there was increased arginase I expression in RBCs, whereas no arginase II expression was detected. Moreover, high glucose and RNS stimulation increased arginase activity in H-RBCs, while ROS/RNS scavenging decreased arginase activity in T2DM-RBCs. This study demonstrates a novel mechanism behind endothelial dysfunction that T2DM-RBCs induce endothelial dysfunction via ROS/RNS-dependent up-regulation of arginase I. Targeting arginase I in RBCs may serve as a novel therapeutic tool for treatment of endothelial dysfunction in T2DM.

Cells ◽  
2020 ◽  
Vol 9 (7) ◽  
pp. 1712 ◽  
Author(s):  
Ali Mahdi ◽  
John Tengbom ◽  
Michael Alvarsson ◽  
Bernhard Wernly ◽  
Zhichao Zhou ◽  
...  

We recently showed that red blood cells (RBCs) from patients with type 2 diabetes mellitus (T2DM-RBCs) induce endothelial dysfunction through a mechanism involving arginase I and reactive oxygen species. Peroxynitrite is known to activate arginase in endothelial cells. Whether peroxynitrite regulates arginase activity in RBCs, and whether it is involved in the cross-talk between RBCs and the vasculature in T2DM, is unclear and elusive. The present study was designed to test the hypothesis that endothelial dysfunction induced by T2DM-RBCs is driven by peroxynitrite and upregulation of arginase. RBCs were isolated from patients with T2DM and healthy age matched controls. RBCs were co-incubated with aortae isolated from wild type rats for 18 h in the absence and presence of peroxynitrite scavenger FeTTPS. Evaluation of endothelial function in organ chambers by cumulative addition of acetylcholine as well as measurement of RBC and vessel arginase activity was performed. In another set of experiments, RBCs isolated from healthy subjects (Healthy RBCs) were incubated with the peroxynitrite donor SIN-1 with subsequent evaluation of endothelial function and arginase activity. T2DM-RBCs, but not Healthy RBCs, induced impairment in endothelial function, which was fully reversed by scavenging of RBC but not vascular peroxynitrite with FeTPPS. Arginase activity was up-regulated by the peroxynitrite donor SIN-1 in Healthy RBCs, an effect that was inhibited by FeTTPS. Healthy RBCs co-incubated with aortae in the presence of SIN-1 caused impairment of endothelial function, which was inhibited by FeTTPS or the arginase inhibitor ABH. T2DM-RBCs induced up-regulation of vascular arginase, an effect that was fully inhibited by FeTTPS. Collectively, our data indicate that RBCs impair endothelial function in T2DM via an effect that is driven by a peroxynitrite-mediated increase in arginase activity. This mechanism may be targeted in patients with T2DM for improvement in endothelial function.


2013 ◽  
Vol 53 (3) ◽  
pp. 239-245 ◽  
Author(s):  
Ebrahim Mostafavi ◽  
Manouchehr Nakhjavani ◽  
Zaniar Ghazizadeh ◽  
Hassan Barakati ◽  
Hossein Mirmiranpour ◽  
...  

Metabolism ◽  
1999 ◽  
Vol 48 (12) ◽  
pp. 1481-1484 ◽  
Author(s):  
Dildar Konukoğlu ◽  
Tülay Akçay ◽  
Yıldız Dinçer ◽  
Hüsrev Hatemi

2019 ◽  
Vol 10 ◽  
Author(s):  
Ali Mahdi ◽  
Tong Jiao ◽  
Jiangning Yang ◽  
Oskar Kövamees ◽  
Michael Alvarsson ◽  
...  

Diabetes ◽  
2018 ◽  
Vol 67 (Supplement 1) ◽  
pp. 485-P
Author(s):  
CHRISTINA KOSTARA ◽  
ELENI BAIRAKTARI ◽  
MOSES ELISAF ◽  
VASILEIOS TSIMIHODIMOS

Circulation ◽  
2015 ◽  
Vol 132 (suppl_3) ◽  
Author(s):  
Rosa Breton-Romero ◽  
Bihua Feng ◽  
Monika Holbrook ◽  
Melissa G Farb ◽  
Jessica L Fetterman ◽  
...  

Introduction: Diabetes mellitus type 2 is an increasingly public health problem and it is a major cause in the development of cardiovascular diseases. Endothelial dysfunction is a key mechanism that contributes to the pathogenesis of cardiovascular diseases and is a well-known feature of clinical diabetes. Prior studies have demonstrated an impaired nitric oxide bioavailability and a reduced endothelium-dependent vasodilation under diabetic conditions and in animal models, JNK activity has been widely described to be involved in systemic insulin resistance. Hypothesis: Our study aimed to evaluate the involvement of JNK in endothelial dysfunction, studying its potential role in altered eNOS activation and NO synthesis in diabetic patients. Methods: We measured endothelial function and JNK activity in freshly isolated endothelial cells from diabetic patients (n=38) and nondiabetic controls (n=40). Results: ECs from diabetic patients displayed impaired eNOS activation and reduced NO release after insulin and A23187 stimulation, consistent with the presence of endothelial dysfunction. JNK activation was higher in diabetic (**P=0.003), and was associated with lower flow-mediated dilation (r=-0.53, *P=0.02). In endothelial cells from diabetic patients, treatment with JNK chemical inhibitor (SP600125) restored eNOS activation and insulin response (***P<0.001). Nitric oxide bioactivity after A23187 stimuli with diabetes was also recovered in endothelial cells from patients with diabetes. Conclusions: In summary, our data suggest that JNK activation contributes to vascular insulin resistance and endothelial dysfunction in patients with type 2 diabetes and may represent a target in novel therapeutic opportunities.


Hypertension ◽  
2016 ◽  
Vol 68 (suppl_1) ◽  
Author(s):  
Nathanne S Ferreira ◽  
Thiago Bruder-Nascimento ◽  
Camila A Pereira ◽  
Camila Z Zanotto ◽  
Douglas S Prado ◽  
...  

Diabetic patients and animal models of type 2 diabetes (DM2) display increased plasma aldosterone (aldo) levels. Aldo induces vascular inflammation and endothelial dysfunction. NOD-like receptors, which are pattern recognition receptors involved in a variety of host innate immune responses, promote vascular inflammation. We hypothesized that aldo via mineralocorticoid receptors (MR) activates the inflammasome platform in the vasculature of DM2 mice. Control (db/+) and diabetic (db/db) mice were treated with vehicle or spironolactone (spiro - MR antagonist, 50 mg/Kg/day). Mesenteric resistance arteries (MA) from db/db mice exhibited reduced acetylcholine (ACh) dilation, which was reversed by spiro [Emax (% of relaxation): db/+: 78.5±4.1; db/db: 40.5±6.4; db/+spiro: 77.0±3.8; db/db+spiro: 62.8±5.9 n=3-6 p<0.05]. Spiro treatment reduced caspase-1 and mature IL-1β content in MA from db/db mice. Spiro also reduced caspase-1 activity in macrophages from peritoneal lavage of db/db mice [% of activity: db/+: 33.9±2.5; db/db: 51.8±7.4; db/+spiro: 31.1±1.9; db/db+spiro: 34.8±3.8 n=4-7, p<0.05]. In vitro, aldo increased mature IL-1β in vascular smooth muscle cells (VSMC) (cont: 0.9±0.01 ; LPS+Nigericine: 6.1±2.1 ; Aldo 4h: 9.7±2.6; LPS+Aldo 4h: 12.8±1.9 n=3-5, p<0.05). To determine whether aldo in vivo directly activates NLRP3/inflammasome in the vasculature and whether NLRP3 activation contributes to aldo-induced vascular injury, aldo was infused (600 ug/Kg/day for 14 days) in wild type (WT) and NLRP3 knockout mice ( NLRP3-/- ) after bone marrow transplantation from WT donor. The groups were constituted: WT->WT, WT->WT+aldo and WT-> NLRP3 -/-+aldo. NLRP3 -/- mice were protected against aldo-induced endothelial dysfunction [Emax: WT: 89.3±2.9; WT+aldo: 39.8±1.8; NLRP3-/- +aldo: 87.7±4.2, p<0.05]. Aldo treatment leaded to endothelial dysfunction in WT ->WT mice, but WT-> NLRP3 -/- mice were protected from aldo-induced endothelial dysfunction [Emax: WT->WT: 95.1±3.1; WT->WT+aldo: 57.1±4.7; WT->NLRP3-/-+aldo: 85.3±3.1 p<0.05]. These results suggest that NLRP3/inflammasome in the vasculature plays a crucial role on aldo/MR-induced vascular damage and on DM2-associated vascular dysfunction. Financial Support: FAPESP, CAPES, CNPq.


2004 ◽  
Vol 5 (1) ◽  
pp. 37-50 ◽  
Author(s):  
P. Vague ◽  
T. C. Coste ◽  
M. F. Jannot ◽  
D. Raccah ◽  
M. Tsimaratos

Na+,K+-ATPase is an ubiquitous membrane enzyme that allows the extrusion of three sodium ions from the cell and two potassium ions from the extracellular fluid. Its activity is decreased in many tissues of streptozotocin-induced diabetic animals. This impairment could be at least partly responsible for the development of diabetic complications.Na+,K+-ATPase activity is decreased in the red blood cell membranes of type 1 diabetic individuals, irrespective of the degree of diabetic control. It is less impaired or even normal in those of type 2 diabetic patients. The authors have shown that in the red blood cells of type 2 diabetic patients,Na+,K+-ATPase activity was strongly related to blood C-peptide levels in non–insulin-treated patients (in whom C-peptide concentration reflects that of insulin) as well as in insulin-treated patients. Furthermore, a gene-environment relationship has been observed. The alpha-1 isoform of the enzyme predominant in red blood cells and nerve tissue is encoded by theATP1A1gene.Apolymorphism in the intron 1 of this gene is associated with lower enzyme activity in patients with C-peptide deficiency either with type 1 or type 2 diabetes, but not in normal individuals. There are several lines of evidence for a low C-peptide level being responsible for lowNa+,K+-ATPase activity in the red blood cells. Short-term C-peptide infusion to type 1 diabetic patients restores normalNa+,K+-ATPase activity. Islet transplantation, which restores endogenous C-peptide secretion, enhancesNa+,K+-ATPase activity proportionally to the rise in C-peptide. This C-peptide effect is not indirect. In fact, incubation of diabetic red blood cells with C-peptide at physiological concentration leads to an increase ofNa+,K+-ATPase activity. In isolated proximal tubules of rats or in the medullary thick ascending limb of the kidney, C-peptide stimulates in a dose-dependent mannerNa+,K+-ATPase activity. This impairment inNa+,K+-ATPase activity, mainly secondary to the lack of C-peptide, plays probably a role in the development of diabetic complications. Arguments have been developed showing that the diabetesinduced decrease inNa+,K+-ATPase activity compromises microvascular blood flow by two mechanisms: by affecting microvascular regulation and by decreasing red blood cell deformability, which leads to an increase in blood viscosity. C-peptide infusion restores red blood cell deformability and microvascular blood flow concomitantly withNa+,K+-ATPase activity. The defect in ATPase is strongly related to diabetic neuropathy. Patients with neuropathy have lower ATPase activity than those without. The diabetes-induced impairment inNa+,K+-ATPase activity is identical in red blood cells and neural tissue. Red blood cell ATPase activity is related to nerve conduction velocity in the peroneal and the tibial nerve of diabetic patients. C-peptide infusion to diabetic rats increases endoneural ATPase activity in rat. Because the defect inNa+,K+-ATPase activity is also probably involved in the development of diabetic nephropathy and cardiomyopathy, physiological C-peptide infusion could be beneficial for the prevention of diabetic complications.


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