Integrity Of Vascular Endothelium Research Articles

Endothelial life discontinues without Erk.

The mechanism of maintaining vascular endothelial identity and integrity is largely unknown. In this issue of JEM, Ricard et al. (https://doi.org/10.1084/jem.20182151) discover essential roles of ERK1/2 in maintaining endothelial homeostasis and its deletion-related serious defects in multiple tissues and organs.

Increased levels of angiogenic factors in microvascular angina.

BackgroundRecent studies have suggested that angiogenic factors may affect vascular endothelial integrity. On the other hand, endothelial dysfunction is the main pathological mechanism in microvascular angina (MVA) or cardiac syndrome X. Therefore, we aimed to determine the levels of angiogenic factors in MVA patients. In addition, we investigated the effects of metoprolol, as a beta blocker agent, on the serum levels of these factors.MethodsThirty patients with MVA (17 female/13 male; mean age: 55.53±9.18 years) and twenty healthy controls (14 female/6 male; mean age: 51.40±9.16 years) were enrolled.The serum amounts of angiopoietin-1 (Ang-1), angiopoietin-2 (Ang-2) and tyrosine kinase-2 receptor (Tie-2) were measured in healthy controls, MVA patients at baseline and after metoprolol therapy (25 mg for one month) by enzyme-linked immunosorbent assay.ResultsThe levels of Ang-2 and Tie-2 were significantly higher in MVA patients at baseline in comparison with controls (Ang-2: 277.02±186.08 vs.164.46±49.83 ng/l, P=0.011; Tie-2: 28.97±18.85 vs. 14.90±4.05 ng/ml, P=0.002; respectively). But this difference in the Ang-1 levels was not significant (P=0.829). Additionally, the levels of angiogenic factors in MVA patients after metoprolol therapy were not significantly changed in comparison with the baseline status (P>0.05).ConclusionOur results considered a possible role for angiogenic factors in the pathophysiology of MVA, which need further investigation for elucidation. In addition, this study has not showed an effective role for metoprolol in changing the angiogenic factors levels as a therapeutic agent in MVA.

Neutrophil elastase inhibition effectively rescued angiopoietin-1 decrease and inhibits glial scar after spinal cord injury

After spinal cord injury (SCI), neutrophil elastase (NE) released at injury site disrupts vascular endothelium integrity and stabilization. Angiopoietins (ANGPTs) are vascular growth factors that play an important role in vascular stabilization. We hypothesized that neutrophil elastase is one of the key determinants of vascular endothelium disruption/destabilization and affects angiopoietins expression after spinal cord injury. To test this, tubule formation and angiopoietins expression were assessed in endothelial cells exposed to different concentrations of recombinant neutropil elastase. Then, the expression of angiopoietin-1, angiopoietin-2, and neutrophil elastase was determined at 3 h and at 1, 3, 5, 7, 14, 21, and 28 days in a clinically relevant model of moderate compression (35 g for 5 min at T10) spinal cord injury. A dichotomy between the levels of angiopoietin-1 and angiopoietin-2 was observed; thus, we utilized a specific neutrophil elastase inhibitor (sivelestat sodium; 30 mg/kg, i.p., b.i.d.) after spinal cord injury. The expression levels of neutropil elastase and angiopoietin-2 increased, and that of angiopoietin-1 decreased after spinal cord injury in rats. The sivelestat regimen, optimized via a pharmacokinetics study, had potent effects on vascular stabilization by upregulating angiopoietin-1 via the AKT pathway and preventing tight junction protein degradation. Moreover, sivelestat attenuated the levels of inflammatory cytokines and chemokines after spinal cord injury and hence subsequently alleviated secondary damage observed as a reduction in glial scar formation and the promotion of blood vessel formation and stabilization. As a result, hindlimb locomotor function significantly recovered in the sivelestat-treated animals as determined by the Basso, Beattie, and Bresnahan scale and footprint analyses. Furthermore, sivelestat treatment attenuated neuropathic pain as assessed by responses to von Frey filaments after spinal cord injury. Thus, our result suggests that inhibiting neutropil elastase by administration of sivelestat is a promising therapeutic strategy to inhibit glial scar and promote functional recovery by upregulating angiopoietin-1 after spinal cord injury.

Abstract 5067: b1-Integrin promotes inflammatory cytokine-induced vascular leakage

Abstract Increased capillary leakage is a potentially life-threatening condition associated with sepsis and cytokine release syndrome (CRS) that develops as a side effect of novel chimeric antigen receptor (CAR) T-cell cancer immunotherapies. CRS and sepsis are characterized by immune activation, resulting in elevated circulating levels of inflammatory cytokines including IL-6 and IL-1β, and thrombin that promote vascular leakage and the development of hypovolemic shock and multiorgan failure. However, molecular mechanisms behind capillary leakage remain unknown, and importantly, targeted approaches for the management of capillary leakage are limited. Here, we found that β1-integrin acts as a critical universal mediator of endothelial permeability induced by various inflammatory agents, including LPS, IL-6, IL-1β and thrombin. In a mouse model of LPS-induced systemic inflammation, resulting in increased inflammatory cytokine production and vascular leakage, function blocking antibodies against β1-integrin prevented vascular leakage and improved integrity of vascular endothelium, leading to protection from LPS-induced cardiac failure. β1-integrin blocking antibodies were effective in reducing vascular leakage even when administered after the onset of systemic inflammation and increase in the serum levels of IL-6, IL-1β and TNF-α. By using an in vitro model, we found that inflammatory agents generated mechanical stress, in a β1-integrin dependent manner, leading to endothelial cell contractility and permeability. Conclusively, our data indicates that β1-integrin promotes vascular leakage in inflammation, and that targeting this mechanism may have therapeutic utility for vascular stabilization in CRS and capillary leak syndromes associated with immune activation and systemic inflammation. Citation Format: Elina A. Kiss, Laura Hakanpää, Guillaume Jacquemet, Ilkka Miinalainen, Martina Lerche, Camilo Guzman, Eero Mervaala, Lauri Eklund, Johanna Ivaska, Pipsa Saharinen. b1-Integrin promotes inflammatory cytokine-induced vascular leakage [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5067.

Upregulation of P2Y2R, Active uPA, and PAI-1 Are Essential Components of Hantavirus Cardiopulmonary Syndrome.

Sin Nombre virus (SNV) causes hantavirus cardiopulmonary pulmonary syndrome (HCPS) with the loss of pulmonary vascular endothelial integrity, and pulmonary edema without causing cytopathic effects on the vascular endothelium. HCPS is associated primarily with a dysregulated immune response. We previously found occult signs of hemostatic imbalance in the form of a sharp >30–100 fold increase in the expression of plasminogen activator inhibitor type 1 (PAI-1), in serial blood plasma draws of terminal stage-patients. However, the mechanism of the increase in PAI-1 remains unclear. PAI-1 is a primary inhibitor of fibrinolysis caused by tissue plasminogen activator (tPA) and urokinase plasminogen activator plasma (uPA). Here, we investigate factors that contribute to PAI-1 upregulation during HCPS. Using zymography, we found evidence of PAI-1-refractory uPA activity and no tPA activity in plasma samples drawn from HCPS patients. The sole prevalence of uPA activity suggested that severe inflammation drove PAI-1 activity. We have recently reported that the P2Y2 receptor (P2Y2R) mediates SNV infectivity by interacting in cis with β3 integrins, which activates the latter during infection. P2Y2R is a known effector for several biological processes relevant to HCPS pathogenesis, such as upregulation of tissue factor (TF), a primary initiator of the coagulation cascade, stimulating vascular permeability and leukocyte homing to sites of infection. As P2Y2R is prone to upregulation under conditions of inflammation, we compared the expression level of P2Y2R in formalin fixed tissues of HCPS decedents using a TaqMan assay and immunohistochemistry. Our TaqMan results show that the expression of P2Y2R is upregulated significantly in HCPS cases compared to non- HCPS controls (P < 0.001). Immunohistochemistry showed that lung macrophages were the primary reservoir of high and coincident localization of P2Y2R, uPA, PAI-1, and TF antigens. We also observed increased staining for SNV antigens in the same tissue segments where P2Y2R expression was upregulated. Conversely, sections of low P2Y2R expression showed weak manifestations of macrophages, SNV, PAI-1, and TF. Coincident localization of P2Y2R and PAI-1 on macrophage deposits suggests an inflammation-dependent mechanism of increasing pro-coagulant activity in HCPS in the absence of tissue injury.

Daily melatonin protects the endothelial lineage and functional integrity against the aging process, oxidative stress, and toxic environment and restores blood flow in critical limb ischemia area in mice.

We tested the hypothesis that daily melatonin treatment protects endothelial lineage and functional integrity against the aging process, oxidative stress/endothelial denudation (ED), and toxic environment and restored blood flow in murine critical limb ischemia (CLI). In vitro study using HUVECs, in vivo models (ie, CLI through left femoral artery ligation and ED through carotid artery wire injury), and model of lipopolysaccharide-induced aortic injury in young (3months old) and aged (8months old) mice were used to elucidate effects of melatonin treatment on vascular endothelial integrity. In vitro study showed that menadione-induced oxidative stress (NOX-1/NOX-2), inflammation (TNF-α/NF-kB), apoptosis (cleaved caspase-3/PARP), and mitochondrial damage (cytosolic cytochrome c) in HUVECs were suppressed by melatonin but reversed by SIRT3-siRNA (all P<.001). In vivo, reduced numbers of circulating endothelial progenitor cells (EPCs) (C-kit/CD31+/Sca-1/KDR+/CXCR4/CD34+), and angiogenesis (Matrigel assay of bone marrow-derived EPC and ex vivo aortic ring cultures) in older (compared with younger) mice were significantly reversed through daily melatonin administration (20mg/kg/d, ip) (all P<.001). Aortic vasorelaxation and nitric oxide release were impaired in older mice and reversed in age-match mice receiving melatonin (all P<.01). ED-induced intimal/medial hyperplasia, reduced blood flow to ischemic limb, and angiogenesis (reduced CD31+/vWF+ cells/small vessel number) were improved after daily melatonin treatment (all P<.0001). Lipopolysaccharide-induced aortic endothelial cell detachment, which was more severe in aged mice, was also alleviated after daily melatonin treatment (P<.0001). Daily melatonin treatment protected both structural and functional integrity of vascular endothelium against aging-, oxidative stress-, lipopolysaccharide-, and ischemia-induced damage probably through upregulating the SIRT signaling pathway.

Vasodilator effects and putative guanylyl cyclase stimulation by 2-nitro-1-phenylethanone and 2-nitro-2-phenyl-propane-1,3-diol on rat aorta

Compounds containing a nitro group may reveal vasodilator properties. Several nitro compounds have a NO2 group in a short aliphatic chain connected to an aromatic group. In this study, we evaluated in rat aorta the effects of two nitro compounds, with emphasis on a putative recruitment of the soluble guanylate cyclase (sGC) pathway to induce vasodilation. Isolated aortic rings were obtained from male Wistar rats to compare the effects induced by 2-nitro-1-phenylethanone (NPeth) or 2-nitro-2-phenyl-propane-1,3-diol (NPprop). In aortic preparations contracted with phenylephrine or KCl, NPeth and NPprop induced vasorelaxant effects that did not depend on the integrity of vascular endothelium. NPeth had a lesser vasorelaxant efficacy than NPprop and only the NPprop effects were inhibited by pretreatment with the sGC inhibitors, 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ) or methylene blue. In an ODQ-preventable manner, NPprop inhibited the contractile component of the phenylephrine-induced response mediated by intracellular Ca2+ release or by extracellular Ca2+ recruitment through receptor- or voltage-operated Ca2+ channels. In contrast, NPprop was inert against the transient contraction induced by caffeine in Ca2+-free medium. In an ODQ-dependent manner, NPprop inhibited the contraction induced by the protein kinase C activator phorbol 12,13-dibutyrate or by the tyrosine phosphatase inhibitor sodium orthovanadate. In silico docking analysis of a sGC homologous protein revealed preferential site for NPprop. In conclusion, the nitro compounds NPeth and NPprop induced vasorelaxation in rat aortic rings. Aliphatic chain substituents selectively interfered in the ability of these compounds to induce vasorelaxant effects, and only NPprop relaxed aortic rings via a sGC pathway.

Dasatinib reversibly disrupts endothelial vascular integrity by increasing non-muscle myosin II contractility in a ROCKdependent manner.

Dasatinib reversibly disrupts endothelial vascular integrity by increasing non-muscle myosin II contractility in a ROCKdependent manner.

Divergent Role of Sphingosine 1-Phosphate in Liver Health and Disease.

Two decades ago, sphingosine 1-phosphate (S1P) was discovered as a novel bioactive molecule that regulates a variety of cellular functions. The plethora of S1P-mediated effects is due to the fact that the sphingolipid not only modulates intracellular functions but also acts as a ligand of G protein-coupled receptors after secretion into the extracellular environment. In the plasma, S1P is found in high concentrations, modulating immune cell trafficking and vascular endothelial integrity. The liver is engaged in modulating the plasma S1P content, as it produces apolipoprotein M, which is a chaperone for the S1P transport. Moreover, the liver plays a substantial role in glucose and lipid homeostasis. A dysfunction of glucose and lipid metabolism is connected with the development of liver diseases such as hepatic insulin resistance, non-alcoholic fatty liver disease, or liver fibrosis. Recent studies indicate that S1P is involved in liver pathophysiology and contributes to the development of liver diseases. In this review, the current state of knowledge about S1P and its signaling in the liver is summarized with a specific focus on the dysregulation of S1P signaling in obesity-mediated liver diseases. Thus, the modulation of S1P signaling can be considered as a potential therapeutic target for the treatment of hepatic diseases.

Vascular endothelium dysfunction: a conservative target in metabolic disorders.

Vascular endothelium plays a role in capillary transport of nutrients and drugs and regulates angiogenesis, homeostasis, as well as vascular tone and permeability as a major regulator of local vascular homeostasis. The present study has been designed to investigate the role of endothelium in metabolic disorders. The endothelium maintains the balance between vasodilatation and vasoconstriction, procoagulant and anticoagulant, prothrombotic and antithrombotic mechanisms. Diabetes mellitus causes the activation of aldose reductase, polyol pathway and advanced glycation-end-product formation that collectively affect the phosphorylation status and expression of endothelial nitric oxide synthatase (eNOS) and causes vascular endothelium dysfunction. Elevated homocysteine levels have been associated with increase in LDL oxidation, generation of hydrogen peroxides, superoxide anions that increased oxidative degradation of nitric oxide. Hyperhomocysteinemia has been reported to increase the endogenous competitive inhibitors of eNOS viz L-N-monomethyl arginine (L-NMMA) and asymmetric dimethyl arginine (ADMA) that may contribute to vascular endothelial dysfunction. Hypercholesterolemia stimulates oxidation of LDL cholesterol, release of endothelins, and generation of ROS. The increased cholesterol and triglyceride level and decreased protective HDL level, decreases the activity and expression of eNOS and disrupts the integrity of vascular endothelium, due to oxidative stress. Hypertension also stimulates release of endothelins, vasoconstrictor prostanoids, angiotensin II, inflammatory cytokines, xanthine oxidase and, thereby, reduces bioavailability of nitric oxide. Thus, the cellular and molecular mechanisms underlying diabetes mellitus, hyperhomocysteinemia, hypercholesterolemia hypertension and hyperuricemia leads to an imbalance of phosphorylation and dephosphorylation status of lipid and protein kinase that cause modulation of vascular endothelial L-arginine/nitric oxide synthetase (eNOS), to produce vascular endothelium dysfunction.

Particulate matter disrupts human lung endothelial cell barrier integrity via Rho-dependent pathways.

Increased exposure to ambient particulate matter (PM) is associated with elevated morbidity and mortality in patients with cardiopulmonary diseases and cancer. We and others have shown that PM induces lung microvascular barrier dysfunction which potentially enhances the systemic toxicity of PM. However, the mechanisms by which PM disrupts vascular endothelial integrity remain incompletely explored. We hypothesize that PM induces endothelial cell (EC) cytoskeleton rearrangement via Rho GTPase-dependent pathways to facilitate vascular hyperpermeability. Fine PM induced time-dependent activation of cytoskeletal machinery with increases in myosin light chain (MLC) phosphorylation and EC barrier disruption measured by transendothelial electrical resistance (TER), events attenuated by the Rho-dependent kinase (ROCK) inhibitor Y-27632 or the reactive oxygen species (ROS) scavenger, N-acetylcysteine (NAC). Both Y-27632 and NAC prevented PM-induced stress fiber formation and phospho-MLC accumulation in human lung ECs. PM promotes rapid accumulation of Rho-GTP. This event is attenuated by NAC or knockdown of RhoA (siRNA). Consistent with ROCK activation, PM induced phosphorylation of myosin light chain phosphatase (MYPT) at Thr850, a post-translational modification known to inhibit phosphatase activity. Furthermore, PM activates the guanine nucleotide exchange factor (GEF) for Rho, p115, with p115 translocation to the cell periphery, in a ROS-dependent manner. Together these results demonstrate that fine PM induces EC cytoskeleton rearrangement via Rho-dependent pathways that are dependent upon the generation of oxidative stress. As the disruption of vascular integrity further contributes to cardiopulmonary physiologic derangements, these findings provide pharmacologic targets for prevention of PM-induced cardiopulmonary toxicity.

Endothelial integrity may be regulated by a specific antigen via an IgE-mediated mechanism.

Human vascular endothelial function and integrity may be regulated by many non-specific factors. However, the potential influence of specific antigens via an IgE-mediated mechanism remains unknown. The aim of the study was to determine the expression of the IgE receptors FcεRI and FcεRII in the human vascular endothelium and to assess their relevance in the IgE-mediated regulation of endothelial integrity. FcεRI and FcεRII expression in human umbilical vein endothelial cells (HUVEC) was genetically assessed by PCR with respective primers and sequencing. HUVEC were cultured with IL-4, and changes in FcεRI and FcεRII mRNA expression were analyzed by real-time PCR. Changes in the integrity of endothelium pre-treated with anti-BSA-DNP IgE following exposure to the specific BSA-DNP antigen was assessed using the Real-time Cell Electric Impedance Sensing system (RTCA-DP). PCR and sequencing revealed the expression of FcεRI and FcεRII receptors in the human vascular endothelium. IL-4 caused respective 2- and 3-fold increases in FcεRI and FcεRII mRNA expression. Exposure of endothelium pre-treated with anti-BSA-DNP IgE to specific BSA-DNP antigen led to a 20% increase of endothelial integrity (p<0.05) after 24 hours, but only in cells pre-incubated with IL-4. The presence of FcεRI and FcεRII may allow the human vascular endothelium to respond to a specific antigen by increasing its integrity via an IgE-mediated mechanism.

Endothelial progenitor cells and hypertension: current concepts and future implications.

The discovery of endothelial progenitor cells (EPCs), a group of cells that play important roles in angiogenesis and the maintenance of vascular endothelial integrity, has led to considerable improvements in our understanding of the circulatory system and the regulatory mechanisms of vascular homoeostasis. Despite lingering disputes over where EPCs actually originate and how they facilitate angiogenesis, extensive research in the past decade has brought about significant advancements in this field of research, establishing EPCs as an essential element in the pathogenesis of various diseases. EPC and hypertensive disorders, especially essential hypertension (EH, also known as primary hypertension), represent one of the most appealing branches in this area of research. Chronic hypertension remains a major threat to public health, and the exact pathologic mechanisms of EH have never been fully elucidated. Is there a relationship between EPC and hypertension? If so, what is the nature of such relationship-is it mediated by blood pressure alterations, or other factors that lie in between? How can our current knowledge about EPCs be utilized to advance the prevention and clinical management of hypertension? In this review, we set out to answer these questions by summarizing the current concepts about EPC pathophysiology in the context of hypertension, while attempting to point out directions for future research on this subject.

Moderate Versus Heavy Intensity Interval Training For Vascular Health In Post-menopausal Women

PURPOSE: Whilst the menopause has been associated with a decline in vascular function, sedentary postmenopausal women report a dislike of heavy intensity exercise. This study aimed to compare the impact of moderate (MOD) versus heavy (HVY) intensity interval exercise training upon vascular function and endothelial integrity. METHODS: 27 sedentary post-menopausal women completed either MOD (90% lactate threshold (LT) 10:10 s duty cycle) or HVY (120% LT 30:30 s duty cycle) interval exercise training twice per week for 12 weeks. Endothelial function (FMD), peak oxygen uptake (VO2peak), LT, circulating angiogenic cell number (FACS) and adhesive capacity to cultured saphenous vein vascular smooth muscle cells (VSMCs) were recorded prior to and following training. Group and time differences were assessed via two-way mixed mode ANOVA. RESULTS: VO2peak and LT increased in HVY only (VO2peak: MOD: 29.97 ±5.5 to 29.65 ± 5.4; HVY: 30.18 ±5.3 to 32.25 ±6.5 ml/kg/min; interaction P=0.02; LT: MOD: 1.13 ±0.19 to 1.11 ±0.18; HVY 1.09 ±0.15 to 1.22 ±0.17 L/min; interaction P=0.005). FMD (group mean: 4.7 ±2.4 %), brachial diameter (group mean: 3.7 ±0.3 mm) and blood pressure were unaffected by training (P>0.05), whilst peripheral arterial stiffness decreased post training in both groups (-0.58 a.u). [CD34+CD45dim] increased after MOD but not after HVY intensity interval training (MOD: 5.3 ±3.8 to 8.9 ±6.3; HVY: 6.34 ±3.1 to 5.7 ±2.6 CAC/105 leucocytes: interaction P=0.02). The adhesive capacity of CACs to VSMCs was seen to increase by 70% following MOD but only 12 % following HVY (P>0.05), this capacity persisted over 60 min in the MOD group (time x group interaction: P=0.05). CONCLUSION: In post-menopausal women HVY intensity interval training provided greater benefits for cardiorespiratory fitness. However, MOD intensity intervals produced equivalent reductions in arterial stiffness and greater modulation of CAC function perceived as beneficial to endothelial integrity. Neither intensity was sufficient to produce significant changes in FMD. Varying the intensities used in interval exercise prescription may provide the most effective cardiovascular benefits in post-menopausal women.

The effects of 22°C and 4°C storage of platelets on vascular endothelial integrity and function.

Although a majority of the studies conducted to date on platelet (PLT) storage have been focused on PLT hemostatic function, the effects of 4°C PLTs on regulation of endothelial barrier permeability are still not known. In this study, we compared the effects of room temperature (22°C) stored and (4°C) stored PLTs on the regulation of vascular endothelial cell (EC) permeability in vitro and in vivo. Day 1, Day 5, and Day 7 leukoreduced apheresis PLTs stored at 4 or 22°C were studied in vitro and in vivo. In vitro, PLT effects on EC permeability and barrier function, adhesion, and impedance aggregometry were investigated. In vivo, using a mouse model of vascular leak, attenuation of vascular leak and circulating PLT numbers were measured. Treatment of EC monolayers with Day 5 or Day 7 PLTs, stored at both 22°C and 4°C, resulted in similar decreases in EC permeability on average. However, analysis of individual samples revealed significant variation that was donor dependent. Additional in vitro measurements revealed a decrease in inflammatory mediators, nonspecific PLT-endothelial aggregation and attenuated loss of aggregation over time to TRAP, ASPI, ADP, and collagen with 4°C storage. In mice, while 22°C and 4°C PLTs both demonstrated significant protection against vascular endothelial growth factor A (VEGF-A)-induced vascular leak 22°C PLTs exhibited increased protection compared to 4°C PLTs. Systemic circulating levels of 4°C PLTs were decreased compared to 22°C PLTs. In vitro, 4°C-stored PLTs exhibit a greater capacity to inhibit EC permeability than 22°C-stored PLTs. In vivo, 22°C PLTs provide superior control of vascular leak induced by VEGF-A. This discrepancy may be due to increased clearance of 4°C PLTs from the systemic circulation.

PECAM-1 Leu125Val (rs688) Polymorphism and Diabetic Nephropathy in Caucasians with Type 2 Diabetes Mellitus.

Objectives. Platelet endothelial cell adhesion molecule-1 (PECAM-1) plays a key role in the transendothelial migration of circulating leukocytes during inflammation and in the maintenance of vascular endothelial integrity. We hypothesized that genetic variation in PECAM-1 gene could be associated with diabetic nephropathy (DN) and with the level of soluble PECAM-1 in Caucasians with type 2 diabetes mellitus (T2DM). Design and Methods. We analyzed the rs688 single nucleotide polymorphism of PECAM-1 gene C373G (Leu125Val) at exon 3, which encodes the first extracellular Ig-like domain that mediates the homophilic binding of PECAM-1, in 276 T2DM subjects with documented DN (cases) and 375 T2DM subjects without DN (controls), using a polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) strategy. Level of plasma soluble PECAM-1 (sPECAM-1) was measured by ELISA in a subpopulation of 120 diabetics with DN. Results. We found no association between the Leu125Val polymorphism and DN in subjects with T2DM. Likewise, the Leu125Val polymorphism was not associated with serum sPECAM-1 levels in a subpopulation of 120 diabetics with DN. Conclusion. The Leu125Val polymorphism of PECAM-1 and the level of sPECAM-1 are not associated with DN in T2DM subjects of Slovenian origin.

Expression of HMGB1 in septic serum induces vascular endothelial hyperpermeability.

The aim of the present study was to investigate the effects of high mobility group protein B1 (HMGB1), which is expressed in the serum of patients with sepsis, on vascular endothelial permeability. Sera from patients with sepsis were used to treat endothelial cells (ECs), and the effect on endothelial permeability was evaluated using immunofluorescence. The morphologies of endothelial cytoskeletal actin and vascular endothelial (VE)‑cadherin were assessed using laser scanning confocal microscopy. The protein expression levels of HMGB1, B‑cell lymphoma 2 (BCL‑2) and BCL‑2‑associated X protein (BAX) were detected using western blotting. EC apoptosis was measured using flow cytometry. The results demonstrated that HMGB1 was significantly expressed in the serum 24 h following the onset of sepsis, and the expression levels peaked at 48 h, which were sustained until 96 h post‑onset. Compared with the control group, treatment of the ECs with 20% septic serum in vitro significantly increased endothelial monolayer permeability (P<0.01), markedly induced transcellular filamentous (F)‑actin rearrangement with stress fiber formation, and resulted in the localization of VE‑cadherin fragmentations at the cell borders with increased gaps between ECs. Furthermore, flow cytometry showed that the apoptotic rate of ECs was significantly increased following treatment with septic serum. In addition, the expression levels of BAX were significantly increased, whereas the expression levels of BCL‑2 were significantly decreased. Pretreatment with an HMGBI inhibitor (ethyl pyruvate; 5 µM) 24 h prior to treatment with the septic serum attenuated the effects of septic serum treatment. Together, these findings suggested that treatment of ECs with sera from patients with sepsis may induce the loss of vascular endothelial monolayer integrity, elicit the formation of endothelial F‑actin stress fibers and initiate VE‑cadherin redistribution, which may be attributed to high levels of HMGB1 in the serum. This mechanism also appears to involve changes in the activation of BAX and BCL‑2, resulting in EC apoptosis.

Difference of concentration of placental soluble fms-like tyrosine kinase-1(sFlt-1), placental growth factor (PlGF), and sFlt-1/PlGF ratio in severe preeclampsia and normal pregnancy.

BackgroundPlacental soluble fms-like tyrosine kinase-1 (sFlt-1) which is an antagonist of vascular endothelial growth factor and placental growth factor (PIGF), is considered as one of etiology factors cause endothelial damage in preeclampsia due to increase of sFlt-1 level that change vascular endothelial integrity. This study aims to analyze the difference of sFlt-1 and PlGF concentration in severe preeclampsia and normal pregnancy, and the correlation between both in occurrence of severe preeclampsia.MethodThis is case control study involving 18 subjects with severe preeclampsia and 19 subjects with normal pregnancy as controls who met inclusion and exclusion criteria. Concentration of sFlt-1 and PlGF are measured with ELISA. Statistical analysis is performed with Chi square test, Fisher’s exact test, T test, Mann–Whitney test, and Spearman’s rank correlation test.ResultsThis study results in no significant difference in characteristics of gestational age, and parity in both study groups. Median concentration of sFlt-1 in severe preeclampsia is higher (20,524.75 pg/mL) compared with normal pregnancy (6820.4 pg/mL). Concentration of PlGF is lower in severe preeclampsia (47 pg/mL) compared with normal pregnancy (337 pg/mL). sFlt-1 concentration is higher in severe preeclampsia compared to normal pregnancy. PlGF concentration is lower in severe preeclampsia compared to normal pregnancy. Ratio of sFlt-1 and PlGF concentration is significantly correlated in both severe preeclampsia and normal pregnancy.ConclusionsThere is a significant negative correlation between the concentration of sFLt-1 and PlGF in normal pregnancy.

Tie-1: A potential target for anti-angiogenesis therapy.

The tyrosine kinase system angiopoietin (Ang)/Tie interacts with vascular endothelial growth factor pathway and regulates vessel quiescence in adults as well as later steps of the angiogenic cascade related to vessel maturation. Since all Angs are able to bind to Tie-2 but none binds to Tie-1, the function of Tie-2 and its ligands have captured attention. However, emerging evidence indicates unique roles of the orphan receptor Tie-1 in angiogenesis under physiological and pathological conditions. It is required for maintaining vascular endothelial cell integrity and survival during murine embryo development and in adult and may be involved in modulating differentiation of hematopoietic cells in adult. Tie-1 exhibits poor tyrosine kinase activity and signals via forming heterodimers with Tie-2, inhibiting Tie-2 signaling mediated by Angs. This inhibition can be relieved by Tie-1 ectodomain cleavage mediated by tumor- and inflammatory-related factors, which causes destabilization of vessels and initiates vessel remodeling. Up-regulated Tie-1 expression has been found not only in some leukemia cells and tumor related endothelial cells but also in cytoplasm of carcinoma cells of a variety of human solid tumors, which is associated with tumor progression. In addition, it has pro-inflammatory functions in endothelial cells and is involved in some inflammatory diseases associated with angiogenesis. Recent research indicated that Tie-1 gene ablation exhibited significant effects on tumor blood- and lymph-angiogenesis and improved anti-Ang therapy, suggesting Tie-1 may be a potential target for tumor anti-angiogenesis treatment.

Effect of agmatine on experimental vascular endothelial dysfunction.

This study was designed to investigate the effect of agmatine sulfate (AG, CAS2482-00-0) in nicotine (NIC)-induced vascular endothelial dysfunction (VED) in rabbits. NIC was administered to produce VED in rabbits with or without AG for 6 weeks. Serum lipid profile, serum thiobarbituric acid reactive substances, reduced glutathione, superoxide dismutase generation, serum nitrite/nitrate, serum vascular cellular adhesion molecule-1 (VCAM-1), and aortic nuclear factor κB (NF-κB) levels were analyzed.Treatment with AG markedly improves lipid profile and prevented NIC-induced VED and oxidative stress. The mechanism of AG in improving NIC-induced VED may be due to the significant reduction in serum VCAM-1 levels and aortic NF-κB. Thus, it may be concluded that AG reduces the oxidative stress, nitric oxide production, VCAM-1 levels, and aortic NF-κB expression, thereby consequently improving the integrity of vascular endothelium.