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Background Endothelial damage has been described in antiphospholipid antibody (aPL)-positive patients. However, it is uncertain whether circulating endothelial cells (CECs)—which are released when endothelial injury occurs—can be a marker of patients at high risk for thrombosis. Methods Ninety-seven patients with aPL and/or systemic lupus erythematosus (SLE) were included. CECs were determined by an automated CellSearch system. We also assayed plasma levels of tissue factor-bearing extracellular vesicles (TF+/EVs) and soluble triggering receptor expressed on myeloid cells 1 (sTREM-1) as markers of endothelial dysfunction/damage. Results Patients' mean age was 46.1 ± 13.9 years, 77 were women. Thirty-seven had SLE and 75 patients were suffering from antiphospholipid syndrome. Thirty-seven percent of patients presented a medical history of arterial thrombosis and 46% a history of venous thromboembolism (VTE). Thirteen patients had increased levels of CECs (>20/mL), with a mean CEC level of 48.3 ± 21.3 per mL. In univariate analysis, patients with obesity or medical history of myocardial infarction (MI), VTE, or nephropathy had a significant increased CEC level. In multivariate analysis, obesity (odds ratio [OR] = 6.07, 95% confidence interval [CI]: 1.42–25.94), VTE (OR = 7.59 [95% CI: 1.38–41.66]), and MI (OR = 5.5 [95% CI: 1.1–26.6)] were independently and significantly associated with elevated CECs. We also identified significant correlations between CECs and other markers of endothelial dysfunction: sTREM-1 and TF+/EVs. Conclusion This study demonstrated that endothelial injury assessed by the levels of CECs was associated with thromboembolic events in patients with aPL and/or autoimmune diseases.

Although cardiovascular benefits of β 1 -adrenergic receptor blockade have been described in sepsis, little is known about its impact on the adaptive immune response, specifically CD4 T cells. Herein, we study the effects of β 1 -adrenergic receptor modulation on CD4 T-cell function in a murine model of sepsis.Experimental study.University laboratory.C57BL/6 mice.High-grade sepsis was induced by cecal ligation and puncture in wild-type mice (β 1+/+ ) with or without esmolol (a selective β 1 -adrenergic receptor blocker) or in β 1 -adrenergic receptor knockout mice (β 1-/- ). At 18 hours after surgery, echocardiography was performed with blood and spleen collected to analyze lymphocyte function.At 18 hours, β 1+/+ cecal ligation and puncture mice exhibited characteristics of high-grade sepsis and three surrogate markers of immunosuppression, namely decreased splenic CD4 T cells, reduced CD4 T-cell proliferation, and increased regulatory T lymphocyte cell proportions. Pharmacologic and genetic β 1 -adrenergic receptor blockade reversed the impact of sepsis on CD4 T and regulatory T lymphocyte proportions and maintained CD4 T-cell proliferative capacity. β 1 -adrenergic receptor blocked cecal ligation and puncture mice also exhibited a global decrease in both pro- and anti-inflammatory mediators and improved in vivo cardiovascular efficiency with maintained cardiac power index despite the expected decrease in heart rate.β 1 -adrenergic receptor activation enhances regulatory T lymphocyte inhibitory function and thus contributes to sepsis-induced immunosuppression. This can be attenuated by β 1 -adrenergic receptor blockade, suggesting a potential immunoregulatory role for this therapy in the management of sepsis.

Aimsαv integrins are implicated in fibrosis in a number of organs through their ability to activate TGF-β. However their role in vascular fibrosis and collagen accumulation is only partially understood. Here we have used αv conditional knockout mice and cell lines to determine how αv contributes to vascular smooth muscle cell (VSMC) function in vascular fibrosis and the role of TGF-β in that process.Methods and resultsAngiotensin II (Ang II) treatment causes upregulation of αv and β3 expression in the vessel wall, associated with increased collagen deposition. We found that deletion of αv integrin subunit from VSMCs (αvSMKO) protected mice against angiotensin II-induced collagen production and assembly. Transcriptomic analysis of the vessel wall in αvSMKO mice and controls identified a significant reduction in expression of fibrosis and related genes in αvSMKO mice. In contrast, αvSMKO mice showed prolonged expression of CD109, which is known to affect TGF-β signalling. Using cultured mouse and human VSMCs, we showed that overexpression of CD109 phenocopied knockdown of αv integrin, attenuating collagen expression, TGF-β activation, and Smad2/3 signalling in response to angiotensin II or TGF-β stimulation. CD109 and TGF-β receptor were internalized in early endosomes.ConclusionWe identify a role for VSMC αv integrin in vascular fibrosis and show that αv acts in concert with CD109 to regulate TGF-β signalling.

Background Short leukocyte telomere length (TL) is associated with atherosclerotic cardiovascular disease. Endothelial repair plays a key role in the development of atherosclerosis. The objective was to examine associations between TL and proliferative dynamics of endothelial colony‐forming cells (ECFCs), which behave as progenitor cells displaying endothelial repair activity. Methods and Results To isolate ECFCs, we performed a clonogenic assay on blood samples from 116 participants (aged 24–94 years) in the TELARTA (Telomere in Arterial Aging) cohort study. We detected no ECFC clones in 29 (group 1), clones with no replating capacity in other 29 (group 2), and clones with replating capacity in the additional 58 (group 3). Leukocyte TL was measured by Southern blotting and ECFCs (ECFC‐TL). Age‐ and sex‐adjusted leukocyte TL (mean±SEM) was the shortest in group 1 (6.51±0.13 kb), longer in group 2 (6.69±0.13 kb), and the longest in group 3 (6.78±0.09 kb) ( P P P r =0.82; P Conclusions Individuals with longer telomeres display a higher number of self‐renewing ECFCs. Our results also indicate that leukocyte TL, as a proxy of TL dynamics in ECFCs, could be used as a surrogate marker of endothelial repair capacity in clinical and laboratory practice because of easy accessibility of leukocytes. Registration URL: https://www.clinicaltrials.gov ; Unique identifier: NCT02176941.

Les adrénorécepteurs α et en particulier β sont les principales cibles de l’adrénaline et de la noradrénaline libérées par le système sympathique activé. Durant le choc septique, la dysautonomie est une stimulation prolongée à un haut niveau d’intensité du système nerveux sympathique à l’origine d’une altération de la contractilité, de la vasoréactivité et d’une immunodépression. Ainsi, l’administration précoce d’un traitement β-bloquant lors du choc septique pourrait pondérer les effets délétères de cette surstimulation sympathique. Néanmoins, si les preuves expérimentales sont en faveur de cette approche, l’accumulation des preuves cliniques reste encore insuffisante.

International audience; Background: Subjects with heart failure (HF) are at higher risk of developing thrombosis. We investigated whether endothelium activation and inflammation induce a prothrombotic biological profile in patients with acute decompensated HF (ADHF) and sinus rhythm.Methods: Our prospective study included 34 ADHF patients, 30 patients with stable chronic HF (CHF) and 30 control inpatients without HF. In vitro thrombin generation and its downregulation by activated protein C (APC) was monitored by calibrated automated thrombography at hospital admission, at the day of discharge and after discharge, following at least six weeks of clinical stability. Circulating endothelium-derived extracellular vesicles (eEVs) were quantified by flow cytometry and nucleosomes by ELISA.Results: Thrombin generation is increased and APC sensitivity is decreased independently of platelets in ADHF at admission compared to controls (p < 0.01). Thrombin generation was also increased in CHF but only in the presence of platelets. Plasma markers of endothelium activation (von Willebrand factor, factor VIII, procoagulant eEVs and circulating nucleosomes) and the ability of plasmas to induce neutrophil extracellular trap formation in control neutrophils are elevated in ADHF at admission compared to controls (p < 0.001). In-hospital prothrombotic changes in ADHF improved significantly at the post-discharge time-point. Circulating nucleosomes were positively correlated with APC sensitivity (p = 0.013) and annexin-V-positive eEVs (p = 0.004).Conclusions: This proof-of-concept study identified an endothelial-driven hypercoagulable phenotype at the acute phase of decompensated HF contrasting with the platelet-dependent prothrombotic state in CHF. These results highlighted a cross-talk between circulating eEVs and nucleosomes, procoagulant factors and impairment of the APC anticoagulant activity in ADHF.

Background Many arguments suggest that neutrophils could play a prominent role in COVID‐19. However, the role of key components of neutrophil innate immunity in severe forms of COVID‐19 has deserved insufficient attention. We aimed to evaluate the involvement of neutrophil elastase, histone‐DNA, and DNases in systemic and multi‐organ manifestations of COVID‐19. Methods We performed a multicenter study of markers of neutrophil innate immunity in 155 cases consecutively recruited in a screening center, local hospitals, and two regional university hospitals. The cases were evaluated according to clinical and biological markers of severity and multi‐organ manifestations and compared to 35 healthy controls. Results Blood neutrophil elastase, histone‐DNA, myeloperoxidase‐DNA, and free dsDNA were dramatically increased, and DNase activity was decreased by 10‐fold, compared with controls. Neutrophil elastase and histone‐DNA were associated with intensive care admission, body temperature, lung damage, and markers of cardiovascular outcomes, renal failure, and increased interleukin‐6 (IL‐6), IL‐8, and CXCR2. Neutrophil elastase was an independent predictor of the computed tomography score of COVID‐19 lung damage and the number of affected organs, in multivariate analyses. The increased blood concentrations of NE and neutrophil extracellular traps were related to exacerbation of neutrophil stimulation through IL‐8 and CXCR2 increased concentrations and increased serum DAMPs, and to impaired degradation of NETs as a consequence of the dramatic decrease in blood DNase activity. Conclusion Our results point out the key role of neutrophil innate immunity exacerbation in COVID‐19. Neutrophil elastase and DNase could be potential biomarkers and therapeutic targets of severe systemic manifestations of COVID‐19., Blood levels of neutrophil elastase and histone‐DNA are associated with severe and systemic and multi‐organ manifestations of COVID‐19. Increased blood concentrations of neutrophil elastase and neutrophil extracellular traps are related to exacerbation of neutrophil stimulation through activated IL‐8/CXCR2 pathway. Neutrophil elastase and DNase could be potential biomarkers and therapeutic targets of severe systemic manifestations of COVID‐19.

International audience; OBJECTIVE:Preliminary experimental data suggest that selective β1-blockers may improve ex vivo cardiac function in animal sepsis. Currently, the effects of esmolol on in vivo cardiac function and on vascular function are unknown. The present study was designed to examine the effects of the β1-selective blocker esmolol on myocardial and vascular function in peritonitis-induced septic rats and to explore the inflammatory pathways involved in this process.DESIGN:Randomized animal study.SETTING:University research laboratory.SUBJECTS:Male Wistar rats.INTERVENTIONS:Four hours after cecal ligation and puncture, Wistar rats were randomly allocated to the following groups: control, esmolol, norepinephrine (started at 18 hr after the surgery), and esmolol (started at 4 hr after the surgery) + norepinephrine (started at 18 hr after the surgery). Assessment at 18 hours after surgery was focused on cardiac contractility and vascular ex vivo function. Cardiac and vascular protein expressions of nuclear factor κB and endothelial nitric oxide synthase/Akt/inducible nitric oxide synthase pathways were assessed by Western blotting.MEASUREMENTS AND MAIN RESULTS:When compared with sham-operated animals, cecal ligation and puncture animals developed hypotension, cardiac depression, and vascular hyporesponsiveness to vasopressor treatment. Esmolol infusion increased cardiac contractility and restored mesenteric vasoreactivity. This effect was associated with a decrease in nuclear factor κB activation, an increase in Akt and endothelial nitric oxide synthase phosphorylation, and a decrease in inducible nitric oxide synthase expression both at the cardiac and vessel level. Esmolol infusion was also associated with an up-regulation in α1-vascular adrenoreceptors.CONCLUSION:Adjunction of selective β1-blockade to standard septic shock management enhances intrinsic cardiac contractility and vascular responsiveness to catecholamines. These protective cardiovascular effects are likely predominantly attributed to the anti-inflammatory effect of esmolol.

Objective— The hypothesis that hypertension induces a hypercoagulable state arises from the complications associated with hypertension: stroke and myocardial infarction. Here, we determine whether hypertension causes changes in the thrombin-generating capacity of the vascular wall. Approach and Results— We used spontaneously hypertensive rats (SHR) compared with Wistar rats. The addition of thoracic aortic rings of SHR to a Wistar or SHR plasma pool resulted in a greater increase in thrombin generation compared with equivalent rings from Wistar. This increase occurred in 12- but not 5-week-old rats and was prevented by an angiotensin II–converting enzyme inhibitor, indicating that established hypertension is required to induce increased thrombin generation within the vessel wall. Whereas no difference was observed for endothelial cells, thrombin formation was higher on aortic smooth muscle cells (SMCs) from SHR than on those from Wistar. Exposure of negatively charged phospholipids was higher on SHR than on Wistar rings, as well as on cultured SMCs. Tissue factor activity was higher in SHR SMCs. Twelve-week-old SHR exhibited accelerated FeCl 3 -induced thrombus formation in carotid arteries, and the resulting occlusive thrombi were disaggregated by blockade of glycoprotein Ibα–von Willebrand factor interactions. SHR SMCs were more sensitive to thrombin-induced proliferation than Wistar SMCs. This effect was totally abolished by a protease-activated receptor 1 inhibitor. Conclusions— The prothrombotic phenotype of the SHR vessel wall was due to the ability of SMCs to support greater thrombin generation and resulted in accelerated occlusive thrombus formation after arterial injury, which was sensitive to glycoprotein Ibα–von Willebrand factor inhibitors.

Selected paper from the 6th China–France International Symposium “Stem Cells and Regenerative Medicine” and the first meeting of the France–China International CNRS Network (GDRI) CeSMeR, Nancy, 10–13 July 2016; International audience; Mesenchymal stem cells (MSCs) are a common tool in regenerative medicine. The nanoscale extracellular vesicles (nEVs) secreted by these cells were recently brought up to light thanks to their therapeutic potential. In this study, we assessed the in vitro behaviour of human umbilical vein endothelial cells (HUVECs) exposed to nEVs derived from human umbilical cord mesenchymal stem cells (hUC-MSCs). Nanoscale extracellular vesicles were isolated and characterized by NanoSight® and flow cytometry. HUVECs were stimulated with various concentrations of nEVs. To assess nEV interactions with HUVECs, confocal microscopy and angiogenesis assay were performed. The use of nEVs derived from hUC-MSCs was able to produce positive outcomes on HUVECs by acting on their angiogenic potential.

International audience; Cardiogenic shock (CS) patients treated with extracorporeal membrane oxygenation (ECMO) have severe cardiac failure, associated with ischemia-reperfusion. The use of moderate hypothermia during ischemia-reperfusion syndrome is supported by experimental data. We therefore studied the effects of moderate hypothermia on cardiac and vascular function in pig ischemic CS treated with veno-arterial extracorporeal membrane oxygenation (VA-ECMO). CS was induced in 12 anesthetized pigs by coronary ligation. After 1 h of CS, VA-ECMO was initiated and pigs were randomized to normothermia (38°C) or moderate hypothermia (34°C) during 8 h. Intrinsic cardiac function was measured using a left ventricular conductance catheter. At the end of the experiment, tissues were harvested for Western blotting. ECMO associated with norepinephrine infusion and volume resuscitation increased mean arterial pressure, mixed venous oxygen saturation as well as carotid, renal, and coronary blood flow without any differences between normothermia and hypothermia. Hypothermia was associated with less fluid and less norepinephrine infusion, lower lactate level, and higher urinary output. Vascular reactivity was superior in hypothermia comparatively to normothermia as expressed using norepinephrine dose-response curves. Pressure development during isovolumic contraction, left ventricular ejection fraction, and prerecruitable stroke work index were higher in the hypothermia group. There were no differences between normothermia and hypothermia with regard to carotid and mesenteric protein expression for iNOs, eNOS, and phospho AKt/AKt measured at the end of the experimentation. The incidence of surgical bleeding and coagulation disorders was the same in both groups. In conclusion, moderate and rapid hypothermia improves hemodynamics and cardiac and vascular function in a pig model of ischemic CS treated with ECMO.

International audience

Background Administration of a selective β1-blocker, such as esmolol, in human septic shock has demonstrated cardiovascular protective effects related to heart rate reduction. Certain experimental data also indicate that esmolol exerts systemic anti-inflammatory and beneficial effects on vascular tone. Thus, the present study aimed to determine whether a non-chronotropic dose of esmolol maintains its protective cardiovascular and anti-inflammatory effects in experimental septic shock. Methods Four hours after cecal ligation and puncture (CLP), Wistar male rats were randomly allocated to the following groups (n = 8): CLP, CLP + E-1 (esmolol: 1 mg.kg−1.h−1), CLP + E-5 (esmolol: 5 mg.kg−1.h−1), CLP + E-18 (esmolol: 18 mg.kg−1.h−1). An additional eight rats underwent sham operation. All rats received a continuous infusion of saline, analgesic and antibiotics 4 hours after the surgery. Assessment at 18 hours included in vivo cardiac function assessed by echocardiography and ex vivo vasoreactivity assessed by myography. Circulating cytokine levels (IL-6 and IL-10) were measured by ELISA. Cardiac and vascular protein expressions of p-NF-κB, IκBα, iNOS, p-AKT/AKT and p-eNOS/eNOS were assessed by western blotting. Results CLP induced tachycardia, hypotension, cardiac output reduction, hyperlactatemia and vascular hypo-responsiveness to vasopressors. Compared to CLP animals, heart rate was unchanged in CLP + E-1 and CLP + E-5 but was reduced in CLP + E-18. Stroke volume, cardiac output, mean arterial pressure and lactatemia were improved in CLP + E-1 and CLP + E-5, while vascular responsiveness to phenylephrine was only improved in CLP + E-5 and CLP + E-18. Plasma IL-6 levels were decreased in all esmolol groups. p-NF-κB was decreased in both cardiac and vascular tissues in CLP + E-5 and CLP + E-18. Conclusion In experimental septic shock, low doses of esmolol still improved cardiac function and vasoreactivity. These benefits appear to be associated with a modulation of inflammatory pathways. Electronic supplementary material The online version of this article (doi:10.1186/s13054-016-1580-2) contains supplementary material, which is available to authorized users.

CD109 is a glycosylphosphatidylinositol (GPI)-linked glycoprotein located on the plasma membrane and has no intracellular domain. It has been reported that it attenuates the TGF-β signaling in skin fibroblastes and cancer cells by competitive binding to TGF-β factors and promoting internalization and degradation of TGF-β receptors. We found less production of extracellular matrix (ECM) and higher expression of CD109 in the carotids of angiotensin II-treated mice in which integrin alphaV is inactivated specifically in smooth muscle cells (SMC). We want to study the role of CD109 on the production of extracellular matrix proteins in primary SMC. CD109 is overexpressed by expressing vector (in collaboration with Dr. Murakumo Y.) or decreased by CD109 siRNA in SMC that is analyzed by the cellular and molecular methods. Our results showed that the overexpression of full-length form or soluble form of CD109 attenuated the production of ECM proteins such as collagens and fibronectin in SMC, in contrast with the situation in which the CD109 is knock-downed by siRNA. The response to TGF-β1 and angiotensin II treatment is also attenuated in CD109 overexpression SMC and enhanced in CD109 knock-down SMC. The signaling pathways (phosphorylation of ERK, Akt, Smad2/3, STAT3) related to CD109 are under the investigation. The promoter of CD109 is also under the study in order to understand the mechanism leading to upregulation of CD109 in response to angiotensin II treatment in the integrin aphaV SMC-KO mice. CD109 receptor could be one important regulator of vascular fibrosis and potential target for anti-fibrosis treatment.

International audience; OBJECTIVE:Previous studies have suggested that lowering heart rate (HR) by selective β1-blockers improves sepsis-induced cardiac and vascular dysfunction primarily by decreasing proinflammatory pathways. However, the impact of isolated heart rate reduction (HRR) on hemodynamics and inflammatory pathways remains unknown. The present study was designed to assess the effects of HRR by ivabradine, an If channel inhibitor, on cardiovascular function and inflammatory pathways in peritonitis-induced septic shock in rats.DESIGN:Randomized animal study.SETTING:University research laboratory.INTERVENTIONS:Four hours after cecal ligation and puncture (CLP), Wistar rats were randomly allocated to the following groups: CLP (n = 8) and CLP + ivabradine (n = 8, administered per os 4 h after the surgery). Another eight Wistar male rats underwent sham operation. All rats received a continuous infusion of saline (10 mL kg h), analgesic (nalbuphine: 0.2 mg kg h), and antibiotics (imipenem and cilastatin sodium: 10 mg kg) 4 h after the surgery. Assessment at 18 h included hemodynamics, in vivo cardiac function by echocardiography, and ex vivo vasoreactivity by myography. Circulating cytokine levels (TNF-α, IL-6, and IL-10) were measured by ELISA, whereas cardiac and vascular protein expressions of NF-κB/IκBα/iNOS and Akt/eNOS were assessed by Western blotting.RESULTS:Compared with sham animals, CLP induced tachycardia, hypotension, decreased cardiac output, hyperlactatemia, and vascular hyporesponsiveness to vasopressors. Compared with the CLP group, adjunction of ivabradine decreased the HR without any impact on blood pressure, lactatemia, or vascular responsiveness to vasopressors. Adjunction of ivabradine to CLP rats had no impact on TNF-α, IL-6, and IL-10 cytokines, or on the protein expression levels of phosphorylated forms of NF-κB, Akt, eNOS, and degradation of IκBα in cardiac and vascular tissues.CONCLUSION:Isolated HRR by ivabradine in an experimental model of septic shock does not appear to be associated with any effect on the tested parameters of cardiac function or on vascular responsiveness to vasopressors. Moreover, in this setting, ivabradine does not alter the circulating levels of selected pro/anti-inflammatory cytokines or cardiac and vascular NF-κB/IκBα protein expression levels.

BACKGROUND Meta-analyses of antihypertensive therapy suggest that, independently of blood pressure (BP) level, stroke prevention is influenced mainly by calcium-entry blockers (CEB) and cardiac risk prevention by angiotensin-converting enzyme inhibitors (ACEIs). The possibility that central systolic and pulse pressure (PP) reduction differs between the two drug classes for the same mean BP (MBP) has never been explored. Our aim was to compare carotid PP at the same MBP obtained with the CEB, amlodipine, and the ACEI, trandolapril, in spontaneously hypertensive rats (SHR), and to evaluate the resulting changes of fibronectin (Fn) and its integrin alpha5beta1 receptor on central PP and arterial stiffness. METHODS Amlodipine and trandolapril were administered chronically to achieve the same MBP. Carotid arterial systolic BP (SBP) and PP, diameter and incremental elastic modulus (E(inc)) were determined using echo Doppler techniques, and complemented with vascular histomorphometry, and Fn and alpha5beta1-integrin immunolabeling. RESULTS Both drugs produced the same MBP, carotid wall thickness, and stress. Trandolapril reduced PP and E(inc) significantly more than amlodipine, while both agents comparably lowered EIIIA-Fn. Total Fn and alpha-subunit were lowered significantly by trandolapril, but unaffected by amlodipine, indicating that ACEI alone contributed to both diminished carotid stiffness and decrease of the Fn-integrin complex. CONCLUSIONS Results showed that amlodipine and trandolapril have different effects on carotid mechanical properties for comparable MBP reduction. Changes in Fn-integrin complex not only modify consistently ACEI mechanotransduction but also are associated with selective central PP reduction. Whether this property has consequences on cardiovascular (CV) risk remains to be investigated.

Resistance arteries are the site of the earliest manifestations of many cardiovascular and metabolic diseases. Flow (shear stress) is the main physiological stimulus for the endothelium through the activation of vasodilatory pathways generating flow-mediated dilation (FMD). The role of FMD in local blood flow control and angiogenesis is well established, and alterations in FMD are early markers of cardiovascular disorders. α1-Integrin, which has a role in angiogenesis, could be involved in FMD. FMD was studied in mesenteric resistance arteries (MRA) isolated in arteriographs. The role of α1-integrins in FMD was tested with selective antibodies and mice lacking the gene encoding for α1-integrins. Both anti-α1blocking antibodies and genetic deficiency in α1-integrin in mice (α1−/−) inhibited FMD without affecting receptor-mediated (acetylcholine) endothelium-dependent dilation or endothelium-independent dilation (sodium nitroprusside). Similarly, vasoconstrictor tone (myogenic tone and phenylephrine-induced contraction) was not affected. In MRA phosphorylated Akt and phosphatidylinositol 3-kinase (PI3-kinase) were significantly lower in α1−/−mice than in α1+/+mice, although total Akt and endothelial nitric oxide synthase (eNOS) were not affected. Pharmacological blockade of PI3-kinase-Akt pathway with LY-294002 inhibited FMD. This inhibitory effect of LY-294002 was significantly lower in α1−/−mice than in α1+/+mice. Thus α1-integrin has a key role in flow (shear stress)-dependent vasodilation in resistance arteries by transmitting the signal to eNOS through activation of PI3-kinase and Akt. Because of the central role of flow (shear stress) activation of the endothelium in vascular disorders, this finding opens new perspectives in the pathophysiology of the microcirculation and provides new therapeutic targets.

Background We examined the effects of early high salt diet (HSD) and angiotensin II type 1 (AT1) receptor antagonist valsartan (Val) on mortality and carotid distensibility in surviving spontaneously hypertensive rats (SHRs). Methods The HSD was initiated either early (week 4 after birth) or late (week 10), continued until 20 weeks of age, and compared to normal salt diet (NSD) groups. Valsartan was given from the fourth week after birth. Results Eighty-six percent of the rats died in early HSD on placebo, 70% in early HSD on Val-3 mg, 35% in early HSD on Val-30 mg, and 13% in late HSD on placebo. Mean arterial pressure (MAP) was higher in the early HSD and late HSD groups on placebo compared with NSD. The Val-30 mg reduced MAP in all except early HSD groups. Distensibility at MAP (operational distensibility) was lower in late HSD on placebo than in NSD placebo groups. The Val-30 mg increased distensibility in NSD groups. There was no effect of Val in late HSD and early HSD groups. Operational distensibility was negatively correlated with MAP and salt and positively correlated with Val treatment. All animals receiving HSD showed a higher isobaric distensibility in early HSD than in late HSD groups and a smaller distensibility in rats treated with Val. Conclusions Our results showed that administration of early HSD in SHR was associated together with a high mortality, a protective action of Val that increased longevity, and an increased level of isobaric distensibility. Survival in HSD groups suggest a direct role of angiotensin II in salt-induced cardiovascular mortality. This role is associated with MAP independent of changes in carotid stiffness.

International audience; Identification of the mineralocorticoid receptor (MR) in the vasculature (i.e., endothelial and smooth muscle cells) raised the question of its role in vascular function and blood pressure control. Using a mouse model with conditional inactivation of MR in vascular smooth muscle cell (VSMC) (MR(SMKO)), we have recently shown that the VSMC MR is crucial for aldosterone-salt-induced carotid stiffening. In the present study, we have investigated the specific contribution of the VSMC MR in the regulation of vascular tone in large vessels. In MR(SMKO) mice, contractions induced by potassium chloride and calcium (Ca(2+)) are decreased in the aorta, whereas contraction is normal in response to phenylephrine and caffeine. The difference in response to Ca(2+) suggests that the VSMC-specific deficiency of the MR modifies VSM Ca(2+) signaling but without altering the intracellular Ca(2+) store handling. The relaxation induced by acetylcholine is not affected by the absence of MR. However, the relaxation induced by Ach in the presence of indomethacin and the relaxation induced by sodium nitroprussiate are significantly reduced in MR(SMKO) mice compared to controls. Since endothelial nitric oxide synthase (eNOS) activity is increased in mutant mice, their altered relaxation reflects impairment of the nitric oxide (NO) signaling pathway. In addition to altered NO and Ca(2+) signaling, the activity of myosin light chain and its regulators, myosin light chain kinase (MLCK) and myosin phosphatase (MLCP), is reduced. In conclusion, MR expressed in VSMC is required for NO and Ca(2+) signaling pathways and contractile protein activity leading to an altered contraction/relaxation coupling.

Objective The hypothesis that hypertension confers a hypercoagulable state arises from the complications associated with hypertension, stroke and myocardial infarction. Our objective was to determine whether spontaneous hypertension causes changes in the thrombin generating capacity of the vascular wall. Approach and Results We used spontaneously hypertensive rats (SHR) compared with Wistar rats. The addition of thoracic aorta rings of SHR to a Wistar or SHR plasma pool resulted in a greater increase in thrombin generation compared to the addition of equivalent rings from Wistar. Comparison of 5 week-old and 12 week-old rats indicate that established hypertension is required to induce increased thrombin generation within the vessel wall. Whereas no difference was observed for endothelial cells, thrombin formation was higher at the surface of cultured aortic smooth muscle cells (SMCs) from SHR than from Wistar. Exposure of negatively-charged phospholipids was higher on SHR than on Wistar aortic rings as well as on SMCs. Tissue factor activity was higher in SHR SMCs. Twelve week-old SHR exhibited accelerated FeCl3-induced thrombus formation in carotid arteries and the resulting occlusive thrombi are disaggregated by blockade of glycoprotein Ibα-von Willebrand factor interactions. SHR SMCs were more sensitive to thrombininduced proliferation than Wistar SMCs. This cellular effect was totally abolished by a protease-activated receptor 1 inhibitor. Conclusions The prothrombotic phenotype of the SHR vessel wall was due to the ability of SMCs to support greater thrombin generation and resulted in accelerated occlusive thrombus formation after arterial injury, which is sensitive to glycoprotein Ibα-von Willebrand factor inhibitors.

BACKGROUND: The heart rate (HR) reduction obtained by ivabradine is associated in rats with a decrease in diastolic blood pressure (DBP) and mean blood pressure (MBP), and with an increased pulsatile carotid arterial diameter. OBJECTIVE: To determine, in spontaneously hypertensive rats (SHR) and Wistar-Kyoto (WKY) rats, whether acute reductions of the HR in response to ivabradine induced changes in the carotid visco-elastic behavior, as assessed by echo-tracking techniques. METHODS: The hysteresis of the carotid diameter/pressure curve was used to determine the dissipated energy per cardiac cycle, a classical index of arterial viscosity. Four doses of 1 mg/kg intravenous ivabradine were repeated in anesthetized rats to obtain subsequent HR reductions. RESULTS: In WKY, repeated administration of ivabradine produced reduction of MBP, DBP and HR, without change of systolic blood pressure (SBP). In SHR, ivabradine produced a higher reduction in DBP, SBP and HR than in WKY rats, but the increase in pulse pressure was similar in both strains. In SHR and WKY rats, ivabradine did not modify the incremental elastic modulus-stress curves, and shifted the distensibility-pressure curves through changes in blood pressure, indicating no modification in isobaric carotid stiffness. In both strains, ivabradine produced an identical increase of the energy dissipated per cardiac cycle. CONCLUSION: In WKY rats and SHR, acute ivabradine reduces MBP and DBP and increases pulse pressure, but without change in arterial stiffness. In both strains, the HR reduction due to ivabradine induces an identical increase of the energy dissipation of the arterial wall.

Wharton's jelly mesenchymal stromal cells (WJ-MSCs) are promising candidates for tissue engineering, as their immunomodulatory activity allows them to escape immune recognition and to suppress several immune cell functions. To date, however, few studies have investigated the effect of differentiation of the MSCs on this immunomodulation. To address this question, we sought to determine the impact of differentiation toward endothelial cells on immunoregulation by WJ-MSCs. Following differentiation, the endothelial-like cells (ELCs) were positive for CD31, vascular endothelial cadherin and vascular endothelial growth factor receptor 2, and able to take up acetylated low-density lipoproteins. The expression of HLA-DR and CD86, which contribute to MSCs immunoprivilege, was still weak after differentiation. We then co-cultured un- and differentiated MSCs with immune cells, under conditions of both direct and indirect contact. The proliferation and phenotype of the immune cells were analyzed and the mediators secreted by both ELCs and WJ-MSCs quantified. Interleukin (IL)-6, IL-1β, prostaglandin E2 and in particular indoleamine-2,3-dioxygenase expression were upregulated in ELCs on stimulation by T and NK cells, suggesting the possible involvement of these factors in allosuppression. ELCs co-cultured with T cells were able to generate CD25(+) T cells, which were shown to be of the CD4(+)CD25(+)FoxP3(+) regulatory subset. Direct contact between NK cells and ELCs or WJ-MSCs decreased the level of NK-activating receptor natural-killer group 2, member D. Moreover, direct co-culturing with ELCs stimulates CD73 acquisition on NK cells, a mechanism which may induce adenosine secretion by the cells and lead to an immunosuppressive function. Taken together, our results show that ELCs obtained following differentiation of WJ-MSCs remain largely immunosuppressive.

International audience; Previous studies have shown that aldosterone, which activates the mineralocorticoid receptor (MR), promotes thrombosis in animal models. Our objective was to determine whether MR activation/expression in the vascular endothelium could modify thrombotic risk in vivo and to examine thrombin generation at the surface of aortic endothelial cells (HAECs). MR was conditionally overexpressed in vivo in vascular endothelial cells in mice (MR-EC mice) or stimulated with aldosterone in HAECs. Thrombosis after ferric chloride injury was delayed in MR-EC mice compared with controls as well as in wild-type FVB/NRj mice treated with aldosterone (60 μg/kg/d for 21 d). Thrombin generation in platelet-poor plasma did not differ between MR-EC mice and controls. In MR-EC mice, aortic endothelial cell protein C receptor (EPCR) expression was increased. Aldosterone (10(-8) M) attenuated thrombin generation at the surface of cultured HAECs, and this effect was associated with up-regulation of expression of EPCR, which promotes formation of activated protein C. Aldosterone increases EPCR expression via a transcriptional mechanism involving interaction of MR with the specificity protein 1 site. These findings demonstrate that MR activation acts on endothelial cells to protect against thrombosis in physiological conditions and that MR-mediated EPCR overexpression drives this antithrombotic property through enhancing protein C activation.

Durante a recente crise da dívida soberana europeia, os fundos soberanos demonstraram seu peso na esfera financeira global. Contribuíram para salvar o sistema financeiro dos países desenvolvidos, distribuindo créditos que as entidades financeiras tradicionais do Norte não podiam mais providenciar. Em 2012, os ativos totais desses fundos atingiram USD 4.620 bilhões, comparado aos USD 3.355 bilhões de antes da crise, no final de 2007 (Preqin, 2012). Sendo quase todos criados por economias em desenvolvimento ou subdesenvolvidas, os fundos soberanos podem então ser vistos como o símbolo de um recente reequilíbrio do poder a favor desses países (Santiso, 2008). Além disso, em um futuro próximo, espera-se que os fundos soberanos afastem-se dos países desenvolvidos para investir mais em países em desenvolvimento. Nesse contexto, os países africanos estão cada vez mais alvos de investimentos dos fundos (Triki & Faye, 2011). O estudo subjacente analisa dois fundos, o IFC ALAC e o Mubadala Development Company, para entender como, de acordo com as percepções dos seus gestores, os fundos soberanos podem ajudar no desenvolvimento dos países beneficiários. Mais precisamente, trata-se definir, através de um estudo de casos múltiplos, quais são os mecanismos pelos quais os fundos soberanos podem impactar o desenvolvimento da África ocidental. Os resultados sugerem que, segundo os gestores, os fundos soberanos podem desempenhar um papel significativo no desenvolvimento dos países beneficiários. Eles investem em alguns setores-chave da economia (bancos, infraestruturas etc.), criando condições favoráveis ao desenvolvimento local. Além disso, através de um efeito multiplicador, os investimentos dos fundos soberanos alavancam novos investimentos do setor privado local ou global, fortalecendo o tecido industrial e produtivo do país beneficiário. Porém, parece que as empresas beneficiárias não ajudam nas transferências de conhecimento e de tecnologia, embora sejam essenciais para o desenvolvimento econômico, e se limitam a programas de treinamento específico e de RSE. Além disso, apesar dos investimentos de fundos soberanos impulsionarem o crescimento da região, eles também podem agravar a dependência dessas economias à exportação de commodities. Finalmente, os impactos positivos dos fundos soberanos sobre a economia regional são muitas vezes reduzidos devido a conflitos políticos e barreiras estruturais exigindo reformas profundas e de longo prazo.

International audience; Spontaneously hypertensive heart failure rats (SHHF) appear to constitute an original model for analyzing the evolution of the metabolic syndrome towards heart failure. This study aimed to characterize early cardiac dysfunction and remodeling in SHHF rats: (1) as compared with spontaneously hypertensive rats (SHR) and with a control group of Kyoto rats (WKY), and (2) by using the 3-dimensional quantitative analysis provided by acipimox-enhanced positron emission tomography (PET) with (18)F-fluorodesoxyglucose (FDG). Left ventricular (LV) ejection fraction (EF) and volume were quantified by automatic software on the FDG-PET images recorded in SHR (n = 20), SHHF (n = 18) and WKY-rats (n = 19) at ages 3 or 10 months old. Arterial blood pressure was determined by cardiac catheterization and cardiac fibrosis was quantified after sacrifice. Blood pressure was similarly elevated in SHR and SHHF rats (respective systolic blood pressures at 10-months: 199 ± 39 vs. 205 ± 2 mmHg), but SHHF rats had higher body mass than SHR rats (at 10-months, 630 ± 36 vs. 413 ± 27 g, p < 0.05) and higher blood levels of cholesterol and of triglycerides. At 3 months, cardiac parameters did not show significant differences between groups but at 10-months, SHHF and SHR rats exhibited an enhancement in myocardial mass and fibrosis associated with a clear decline in LV-EF (SHHF: 46 ± 6 %; SHR: 47 ± 5 %) as compared with WKY (56 ± 6 %, p < 0.01 for both comparisons). Cardiac remodeling of SHHF rats was clearly observable by FDG-PET from the age of 10-months, but in a similar way to that observed for SHR rats, suggesting a predominant role of hypertension.

Because tissue freeze-drying is an excellent way to preserve antigenic conformation, we have tested the feasibility of this technique to reveal nonradioactive in situ hybridization (ISH) of tissue mRNA. We have compared mRNA detection after different methods of tissue preservation, freeze-drying, cryosectioning, and formaldehyde or methanol fixation. Our results show that nonradioactive ISH is more sensitive for tissues preserved by freeze-drying than for other tissue preparations. We have demonstrated that freeze-drying allows combination of ISH and immunohistochemistry for simultaneous detection of mRNA and antigen because with this technique of tissue preservation ISH does not affect the sensitivity or the amount of the detected antigens. This work underscores the fact that tissue freeze-drying is an easy, convenient, and reliable technique for both ISH and immunohistochemistry and achieves excellent structural conditions for nonradioactive detection.

Vascular cell adhesion molecule-1 (VCAM-1) gene expression in cytokine-activated cells depends on two kappaB elements. Since VCAM-1 expression appears developmentally regulated and cytokine-inducible in smooth muscle cells (SMCs), we have studied the role of NF-kappaB in differentiated SMC VCAM-1 expression. Confluent SMCs were cultured either in a serum-free medium in order to induce differentiation, or in medium with serum, stimulated or not by tumor necrosis factor alpha (TNF-alpha). The expression of smooth muscle myosin heavy chain, a SMC marker, and VCAM-1 was induced concomitantly in serum-free medium, whereas only VCAM-1 expression was induced by cytokine-treatment. We showed that the p50 and p65 subunits of NF-kappaB were localized in the cytoplasm of differentiating SMCs, whereas they were translocated into the nucleus of TNF-alpha-activated SMCs. Electrophoretic mobility shift assays with VCAM-1 gene kappaB elements failed to detect any induction of DNA-protein complex with nuclear extracts of differentiating SMCs in contrast to the cytokine-activated SMC nuclear extracts. Furthermore, VCAM-1 mRNA induction was inhibited in TNF-alpha-stimulated SMCs, but not in differentiating SMCs, by pyrrolidine dithiocarbamate, an inhibitor of NF-kappaB protein activation. Taken together, these findings suggest that in contrast to TNF-alpha activation, NF-kappaB is not involved in VCAM-1 gene expression during SMC differentiation.

Abstract —Vitronectin (VN) is a plasma glycoprotein that promotes cell attachment and induces migration of human smooth muscle cells (SMCs) in culture. VN has been observed to accumulate in human atherosclerotic plaques, although its origin and role in atherosclerosis are not yet established. In the present experiments, synthesis of VN by intimal cells and its colocalization with receptors, αvβ3 and αvβ5, were studied by in situ hybridization and immunohistochemistry on 15 human atherosclerotic plaques from carotid arteries obtained after surgery. Strong VN protein and mRNA expression was observed in the intima and in the media. In the intima, VN mRNA expression was colocalized with SMCs, indicating that these cells produce VN, which may account for its accumulation in atherosclerotic plaques. In SMCs in culture, immunoprecipitation after metabolic labeling demonstrated that human SMCs do synthesize vitronectin. Confocal microscopic examination showed that VN colocalized with its receptors, αvβ3 and αvβ5, in the atherosclerotic intima. However, the distribution of the VN receptors on SMCs in culture in contact with VN was different. These observations suggest that VN plays various parts in atherogenesis via different SMC membrane receptors. ( Arterioscler Thromb Vasc Biol. 1998;18:168-176.)

Aims Vascular smooth muscle cell (VSMC) phenotypic modulation plays a pivotal role in atherothrombotic diseases. Thrombin generation at the surface of VSMCs and activation of integrin mechanotransduction pathways represent potential mechanisms. Here, we examine whether mechanical stretch increases thrombin generation on cultured rat aortic VSMCs. Methods and results The integrin αvβ3 antagonist peptide (cRGDPV) dose-dependently decreased thrombin generation without stretch. Static stretch (5%, 1 Hz) failed to modify the thrombin-forming capacity of VSMCs, whereas 10% cyclic stretch during 60 and 360 min enhanced integrin αvβ3 expression and thrombin generation at the surface of VSMCs by 30% without inducing apoptosis. Cyclic stretch also stimulated Src phosphorylation, cleavage of talin, and binding of prothrombin to VSMCs. Upregulation of αvβ3 expression, Src phosphorylation, and enhanced thrombin generation by cyclic stretch were abolished by cRGDPV and silencing RNA (siRNA) against αv as well as by selective inhibition of integrin αvβ3 inside-out signalling by a talin-siRNA. Complete abolition of stretch-induced VSMC-supported thrombin generation by the RGT peptide, which disrupts the interaction of Src with the β3 cytoplasmic tail, demonstrates the link between outside-in pathways involving β3-Src interaction and thrombin activity dependent on inside-out signalling. Conclusion These data show that the contribution of cyclic stretch to VSMC-supported thrombin generation is driven by the integrin αvβ3 signalling pathway and suggest a role for pulsatility-induced intramural thrombin in VSMC-dependent vascular remodelling.

Objective Previous studies have suggested that lowering heart rate by selective β1-blockers improves sepsis-induced cardiac and vascular dysfunction primarily by decreasing pro-inflammatory pathways. However, the impact of isolated heart rate reduction on hemodynamics and inflammatory pathways remains unknown. The present study was designed to assess the effects of heart rate reduction by Ivabradine, an If channel inhibitor, on cardiovascular function and inflammatory pathways in peritonitis-induced septic shock in rats. Interventions four hours after cecal ligation and puncture (CLP), Wistar rats were randomly allocated to the following groups: CLP (n=8) and Ivabradine (n=8, administered per os at H4). Another eight Wistar male rats underwent sham operation. All rats received a continuous infusion of saline (10 ml.kg-1.h-1), analgesic (nalbuphin: 0.2 mg.kg-1.h-1) and antibiotics (Imipenem and Cilastatin Sodium: 10 mg/kg) four hours after the surgery. Assessment at 18 hours included hemodynamics, in vivo cardiac function by echocardiography and ex vivo vasoreactivity by myography. Cardiac and vascular expressions of NF-κB and eNOS/Akt/iNOS pathways was assessed by western blot. Results Compared to sham animals, CLP induced tachycardia, hypotension, decreased cardiac output, hyperlactatemia and vascular hyporesponsiveness to vasopressors. Compared to the CLP group, adjunction of Ivabradine decreased the heart rate without any impact on blood pressure, lactatemia or vascular responsiveness to vasopressors. Cardiac output was decreased albeit without reaching statistical significance. Ivabradine had no impact on cardiac and vascular protein expression levels of the phosphorylated forms of NF-κB, Akt, eNOS, iNOS. Conclusion Isolated reduction of heart rate by Ivabradine in an experimental model of septic shock does not result in any effect on cardiovascular function and inflammatory pathways. The author hereby declares no conflict of interest

Background: SNPs on chromosome 9p21.3 risk locus have been associated with cardiovascular diseases. We have established a direct mechanistic link between 9p21 noncoding risk interval and susceptibility to aneurysm in a mouse model with a targeted deletion of the 9p21 noncoding cardiovascular disease risk interval. The deficiency of transcripts encoded by this locus predisposes to a pro-thrombotic phenotype and arterial stiffening in this mouse model and in humans with 9p21 DNA variants. Methods: Carotid blood flow following FeCl3 application was monitored via Doppler profiles. Results: The deletion of the orthologous 70-kb noncoding interval on mouse chromosome 4 (chr4Δ70kb/Δ70kb), synthetic to human chromosome 9p21, predisposes to arterial thrombosis. The time to occlusion in a FeCl3-induced carotid thrombosis model was significantly decreased by 30% in the absence of the locus and confirmed by a new model of physiological thrombosis. There was no difference between groups in blood pressure, carotid stiffness parameters (diameter and distensibility for a given level of arterial pressure) or in vascular structure. We explored the potential impact of the deletion locus on thrombin generation as well as on platelet aggregation and reactivity all were increased compared to controls. In 100 healthy carriers of the 9p21 risk T allele display an increased aortic arterial stiffness compared with carriers of the C allele. Conclusion: These results establish a direct link between variants or deletion in the 9p21 non-coding risk interval and increased platelet reactivity and thrombin generation predisposing to thrombosis in mouse and increased arterial stiffness in aged population.

Integrin αv functions as a receptor for adhesion proteins and is expressed at high density in vascular smooth muscle cells (VSMC)1,2,3,4,5 whose phenotypic modulation plays a crucial role in arterial ageing and atherosclerosis.6,7. Our aim was to define the arterial phenotype in mice conditionally inactivated for the integrin αv subunit in VSMC8,9,10(αv SMKO) and its role in angiotensin II (AngII)-induced arterial fibrosis. Transgenic mice αv SMKO and their control littermates (WT) were treated with two doses of AngII, low (0.3 mg/kg/day) and high (1.5 mg/kg/day), for 4 weeks. At baseline, blood pressure was lower in αvSMKO compared to WT mice. Carotid distensibility was increased in αv SMKO mice (13.3±0.7 vs 10.3±0.6 mmHg−1.10−3). With low dose AngII isobaric distensibility remained higher in αvSMKOmice (12.4±1.2 vs 10.7±1.0 mmHg−1.10−3).With high dose AngII the increase in collagen content in carotid media was lower in αvSMKOthan in WT (19 vs 35%) for a similar increase in blood pressure (30 mmHg) and arterial wall hypertrophy. Collagen immunostaining and fluorescence measurements (multiphoton microscopy second harmonic generation) confirmed that high dose AngII induced lower increases in collagen content in αvSMKO mice versus WT (8.9±1.7 vs 14.2±1.4 greyscale mean/pixel). The combination of similar arterial wall hypertrophy with less fibrosis in mutant mice explains an increased distensibility in response to AngII. The αv subunit regulates AngII-induced arterial fibrosis as determined by collagen staining, immunostaining and fluorescence. Pharmacological targeting of vascular αv integrin may have clinical applications in the treatment of patients with fibrosis associated with hypertension and atherosclerosis.

Cardiovascular disease (CVD) is one of the main causes of mortality in the world representing around 30% of all deaths. It constitutes also an important factor in morbidity and incapacity. There are several related CVD risk factors such as hypertension, metabolic syndrome (MetS) and hypercoagulability. The exact mechanisms that underlie the relation between those factors and CVD are not sufficiently known yet; pathogenic explanations are lacking also for the mechanisms relating metabolic factors to insulin resistance (IR) and the association with the development of atherosclerosis and thrombosis. The possible links between hypertension, hemostasis alterations and MetS are examined in this report.

International audience; We aimed to characterize circulating microparticles in association with arterial stiffness, inflammation and endothelial dysfunction in aldosterone-salt-induced hypertension in rats and to investigate the preventive effects of red wine polyphenols. Uninephrectomized male Sprague-Dawley rats were treated with aldosterone-salt (1 mu g.h(-1)), with or without administration of either red wine polyphenols, Provinols (TM) (20 mg.kg(-1).day(-1)), or spironolactone (30 mg.kg(-1).day(-1)) for 4 weeks. Microparticles, arterial stiffness, nitric oxide (NO) spin trapping, and mesenteric arterial function were measured. Aldosterone-salt rats showed increased microparticle levels, including those originating from platelets, endothelium and erythrocytes. Hypertension resulted in enhanced aortic stiffness accompanied by increased circulating and aortic NO levels and an upregulation of aortic inducible NO-synthase, NF kappa B, superoxide anions and nitrotyrosine. Flow-induced dilatation was reduced in mesenteric arteries. These effects were prevented by spironolactone. Provinols (TM) did not reduce arterial stiffness or systolic hypertension but had effects similar to those of spironolactone on endothelial function assessed by flow-mediated vasodilatation, microparticle generation, aortic NO levels and oxidative stress and apoptosis in the vessel wall. Neither the contractile response nor endothelium-dependent relaxation in mesenteric arteries differed between groups. The in vivo effects of Provinols (TM) were not mediated by mineralocorticoid receptors or changes in shear stress. In conclusion, vascular remodelling and endothelial dysfunction in aldosterone-salt-mediated hypertension are associated with increased circulating microparticles. Polyphenols prevent the enhanced release of microparticles, macrovascular inflammation and oxidative stress, and microvascular endothelial dysfunction independently of blood pressure, shear stress and mineralocorticoid receptor activation in a model of hyperaldosteronism.

To analyze age-related interactions between obesity, its associated metabolic disorders, and macrocirculation, we studied large artery stiffness and fatty acid responsiveness in lean and obese Zucker rats, aged 25 (adult) and 80 weeks (very old). Systolic arterial pressure was higher in old obese than in old lean rats (178 ± 10 vs 134 ± 8 mmHg, respectively). Carotid elastic modulus-wall stress curves showed increased age-dependent arterial stiffening, which was greater in obese ani- mals. Old obese exhibited endothelial dysfunction with increased systemic oxidative stress. Adult obese had elevated plasma free fatty acid levels (1,866 ± 177 vs 310 ± 34 mg/mL in lean animals). In old obese, linoleate and palmitate in- creased contractility to phenylephrine and reduced relaxation to acetylcholine. Thus, obesity at 25 weeks appears to trigger accelerated arterial aging observed at 80 weeks. The early increase in free fatty acids may be a key effector in the severe arterial stiffness of the aged obese Zucker model.

Objective— To investigate in women older than 60 whether aortic stiffness or pulse pressure (PP) is associated with selected procoagulant or anticoagulant factors and to examine whether pulsatile stretch influences these factors in human vascular smooth muscle cells (VSMCs) in vitro. Methods and Results— Aortic pulse wave velocity (PWV) and carotid PP were studied in 123 apparently healthy postmenopausal women. PWV, PP, von Willebrand factor, and free tissue factor pathway inhibitor (TFPI), but not mean arterial pressure, increased with age. Free TFPI and PWV were positively correlated, even after adjustment for age and PP and other confounding parameters. In vitro, 5% or 10% pulsatile stretch (at 1 Hz) enhanced TFPI synthesis and secretion by VSMCs in a time-independent manner (1 to 48 hours) without changes in protein level of smooth muscle myosin heavy chain. Application of 5% static stretch had no effect. Conclusion— In postmenopausal women, free TFPI increases as vascular wall function deteriorates and PP increases. These findings are supported by the increase in TFPI synthesized by VSMCs in response to cyclic stress in vitro. They suggest that VSMCs require pulsatility to interfere with the coagulation process and highlight the relevance of plasma free TFPI levels to cardiovascular diseases.

We examined the arterial phenotype of mice lacking α1-integrin (α1−/−) at baseline and after 4 wk of ANG II or norepinephrine (NE) administration. Arterial mechanical properties were determined in the carotid artery (CA). Integrin expression, MAPK kinases, and focal adhesion kinase (FAK) were assessed in the aorta. No change in arterial pressure was observed in α1−/−mice. Elastic modulus-wall stress curves were similar in α1−/−and α1+/+animals, indicating no change in arterial stiffness. The rupture pressure was lower in α1−/−mice, demonstrating decreased mechanical strength. Lack of α1-integrin was accompanied by an increase in β1-, αv-, and α5-integrins but no change in α2-integrin. ANG II increased medial cross-sectional area of the CA in α1+/+, but not α1−/−, mice, whereas equivalent pressor doses of NE did not produce a significant increase in either group. In α1+/+mice, ANG II induced α1-integrin expression and smooth muscle cell (SMC) hypertrophy in the CA in association with increased aortic expression of α-smooth muscle actin and smooth muscle myosin heavy chain and phosphorylation of ERK1/2, p38 MAPK, and FAK. ANG II did not induce SMC hypertrophy or phosphorylation of p38 MAPK and FAK in α1−/−mice. A functional anti-α1-integrin antibody inhibited in vitro the ANG II-induced phosphorylation of FAK and p38 MAPK. In conclusion, α1−/−mice exhibit a reduced mechanical strength at baseline and a lack of ANG II-induced SMC hypertrophy. These results emphasize the importance of α1β1-integrin in p38 MAPK and FAK phosphorylation during vascular hypertrophy in response to ANG II.

This review presents some of the recent technological developments in biomaterials used for the construction of synthetic cardiovascular vessels that are capable of simulating specific biological responses. However, with respect to the problems of stiffness, a major hypertensive risk factor, it is necessary to underline the important role of mechanical properties, such as vessel strength and composition, in vascular reconstructive surgery. Biomaterials occupy a central place in many cardiovascular disease treatments and they depend on the chemical nature of the polymers, on the biotechnology used, and also on cellular and gene therapy. Several methodologies using animal or human cells have emerged for constructing blood vessel replacements. Tissue-engineered blood vessel (TEBV) substitutes begin to motivate much work and have contributed to the restoration, maintenance, and/or improvement in tissue and organ function. Each methodology has it benefits, its promises, and holds many challenges in future biological, biomaterial and clinical research.

Integrin avb3 is expressed at high density in vascular smooth muscle cells (VSMCs). It functions as a receptor for adhesion proteins in VSMCs which phenotypic modulation plays a pivotal role in arteriosclerosis and atherosclerosis. The aim was to study the role of integrin avb3 in angiotensin II (Ang II)-induced arterial fibrosis in mice and in human samples of atherosclerotic arteries in situ. Transgenic mice conditionally inactivated for integrin av subunit in VSMCs (avSMKO) were treated with Ang II (1,5 mg/kg/day) for 4 weeks. Immunostained slices of atherosclerotic plaques at different stages of development and primary cultures of human aortic VSMCs were used. At baseline, blood pressure was lower in avSMKO compared to control (WT) mice. Isobaric carotid distensibility was increased and remained higher in avSMKO in response to Ang II. The increase in collagen content in response to Ang II was lower in avSMKO than in WT (15 vs 36%) for similar increase in blood pressure (20 mmHg) and arterial wall hypertrophy. The immunohistochemistry of aortic slices showed stronger staining for integrin avb3 in atherosclerotic plaques compared to healthy aortas. In VSMC cultures, the mRNA of av was decreased. In conclusion, these results show that avb3 is strongly expressed in neointimal proliferation and in fibrous plaques. The av integrin subunit seems to regulate arterial fibrosis in response to hypertension and plaque growth. Low RNA quantities of av subunit of VSMCs contrasted with strong protein staining in plaques suggesting the participation of inflammatory cells in the synthesis of this integrin.

Stiffening of large arteries is considered as an independent predictor of cardiovascular events. This article summarizes recent theories on the mechanisms contributing to arterial stiffness involving extracellular matrix proteins, endothelial and smooth muscle cells, cell-matrix interactions, and genetic background. Despite the important role of genetic factors in essential hypertension, little is known about the genetic of arterial stiffness. In the future, candidate genes approaches will allow to determine the cellular and molecular mechanisms of arterial stiffness. A review of different strategies aimed at lowering arterial stiffness and potentially reducing cardiovascular risk are presented. Lifestyle changes and antihypertensive drugs have showed beneficial effects in reversing stiffness. New emerging tools as gene therapy and molecules involved in matrix attachments or crosslink of collagen may be promising. Therapeutic trials using such strategies will be necessary to demonstrate their impact on morbidity and mortality.