Abstract-Nitric oxide (NO) is a powerful angiogenic mediator acting downstream of vascular endothelial growth factor (VEGF). Both the endothelial NO synthase (eNOS) and the VEGFR-2 receptor colocalize in caveolae. Because the structural protein of these signaling platforms, caveolin, also represses eNOS activity, changes in its abundance are likely to influence the angiogenic process in various ways. In this study, we used mice deficient for the caveolin-1 gene (Cav Ϫ/Ϫ ) to examine the impact of caveolae suppression in a model of adaptive angiogenesis obtained after femoral artery resection. Evaluation of the ischemic tissue perfusion and histochemical analyses revealed that contrary to Cav ϩ/ϩ mice, Cav Ϫ/Ϫ mice failed to recover a functional vasculature and actually lost part of the ligated limbs, thereby recapitulating the effects of the NOS inhibitor L-NAME administered to operated Cav ϩ/ϩ mice. We also isolated endothelial cells (ECs) from Cav Ϫ/Ϫ aorta and showed that on VEGF stimulation, NO production and endothelial tube formation were dramatically abrogated when compared with Cav ϩ/ϩ ECs. The Ser1177 eNOS phosphorylation and Thr495 dephosphorylation but also the ERK phosphorylation were similarly altered in VEGF-treated Cav Ϫ/Ϫ ECs. Interestingly, caveolin transfection in Cav Ϫ/Ϫ ECs redirected the VEGFR-2 in caveolar membranes and restored the VEGF-induced ERK and eNOS activation. However, when high levels of recombinant caveolin were reached, VEGF exposure failed to activate ERK and eNOS. These results emphasize the critical role of caveolae in ensuring the coupling between VEGFR-2 stimulation and downstream mediators of angiogenesis. This study also provides new insights to understand the paradoxical roles of caveolin (eg, repressing basal enzyme activity but facilitating activation on agonist stimulation) in cardiovascular pathophysiology. Key Words: caveolin-1 Ⅲ nitric oxide Ⅲ vascular endothelial growth factor Ⅲ angiogenesis Ⅲ ischemia C aveolae are 50-to 100-nm cell surface invaginations playing key roles in vesicular transport and signal transduction. 1 The structural protein of these plasmalemmal microdomains, caveolin, acts as a scaffold for many caveolar residents. 2 The caveolin-1 isoform is particularly abundant in endothelial cells (ECs) where it regulates various functions including transcytosis, permeability, vascular tone, and angiogenesis. 3 Recently, Woodman et al 4 documented that in a model of tumor cell injection in caveolin-deficient mice (Cav Ϫ/Ϫ ), angiogenesis was markedly reduced in comparison with wild-type (WT) animals. Although the same authors showed that the reduction in vessel density could be reproduced in a model of Matrigel plugs supplemented with bFGF, 4 the mechanisms supporting the role of caveolin in the angiogenic response to exogenous stimuli remain poorly understood and, based on previous publications, 5-9 a matter of debate.For instance, the well-established inhibitory interaction between caveolin and the endothelial nitric oxide (NO) synthase (eNOS) 10,11 le...

Background-The therapeutic effects of nonspecific ␤-blockers are limited by vasoconstriction, thus justifying the interest in molecules with ancillary vasodilating properties. Nebivolol is a selective ␤ 1 -adrenoreceptor antagonist that releases nitric oxide (NO) through incompletely characterized mechanisms. We identified endothelial ␤ 3 -adrenoreceptors in human coronary microarteries that mediate endothelium-and NO-dependent relaxation and hypothesized that nebivolol activates these ␤ 3 -adrenoreceptors. Methods and Results-Nebivolol dose-dependently relaxed rodent coronary resistance microarteries studied by videomicroscopy (10 mol/L, Ϫ86Ϯ6% of prostaglandin F2␣ contraction); this was sensitive to NO synthase (NOS) inhibition, unaffected by the ␤ 1-2 -blocker nadolol, and prevented by the ␤ 1-2-3 -blocker bupranolol (PϽ0.05; nϭ3 to 8). Importantly, nebivolol failed to relax microarteries from ␤ 3 -adrenoreceptor-deficient mice. Nebivolol (10 mol/L) also relaxed human coronary microvessels (Ϫ71Ϯ5% of KCl contraction); this was dependent on a functional endothelium and NO synthase but insensitive to ␤ 1-2 -blockade (all PϽ0.05). In a mouse aortic ring assay of neoangiogenesis, nebivolol induced neocapillary tube formation in rings from wild-type but not ␤ 3 -adrenoreceptor-or endothelial NOS-deficient mice. In cultured endothelial cells, 10 mol/L nebivolol increased NO release by 200% as measured by electron paramagnetic spin trapping, which was also reversed by NOS inhibition. In parallel, endothelial NOS was dephosphorylated on threonine 495 , and fura-2 calcium fluorescence increased by 91.8Ϯ23.7%; this effect was unaffected by ␤ 1-2 -blockade but abrogated by ␤ 1-2-3 -blockade (all PϽ0.05). Conclusions-Nebivolol dilates human and rodent coronary resistance microarteries through an agonist effect on endothelial ␤ 3 -adrenoreceptors to release NO and promote neoangiogenesis. These properties may prove particularly beneficial for the treatment of ischemic and cardiac failure diseases through preservation of coronary reserve.

Highlights We report 181 people with CF from 19 countries diagnosed with SARS-CoV-2 Spectrum of outcomes observed was similar to that seen in the general population 11 people were admitted to intensive care and 7 died Three of the people who died had received an organ transplant Lower lung function and having been transplanted may be linked to hospitalisation

PIMA is a good POC instrument for screening adult HIV-infected patients in resource-limited settings for treatment eligibility. Its performance on finger-prick blood is not as good as on venous blood. Adequate training for correct use of finger-prick blood samples is mandatory.

Objectives-The interaction of the heat shock protein 90 (Hsp90) with the endothelial NO synthase (eNOS) has been shown to account for a sustained production of NO in vitro. Here, we examined whether overexpression of Hsp90 in a pig model of cardiac infarct could preserve the myocardium from the deleterious effects of ischemia-reperfusion. Methods and Results-Percutaneous liposome-based gene transfer was performed by retroinfusion of the anterior interventricular vein before left anterior descending occlusion and reperfusion. We found that recombinant Hsp90 expression in the ischemic region of the heart led to a 33% reduction in infarct size and prevented the increase in postischemic left ventricular end diastolic pressure observed in mock-transfected animals. Regional myocardial function, assessed by subendocardial segment shortening in the infarct region, was increased in Hsp90-transfected animals at baseline and after pacing. All these effects were completely abrogated by administration of the NOS inhibitor N G -nitro-L-arginine methyl ester. We further documented in vivo and in cultured endothelial cells that the cardioprotective effects of Hsp90 were associated to its capacity to act as an adaptor for both the kinase Akt and the phosphatase calcineurin, thereby promoting eNOS serine 1177 phosphorylation and threonine 495 dephosphorylation, respectively. Conclusions-Hsp90 is a promising target to enhance NO formation in vivo, which may efficiently reduce myocardial reperfusion injury. Key Words: Hsp90 Ⅲ nitric oxide Ⅲ eNOS Ⅲ calcineurin Ⅲ Akt M yocardial ischemia caused by an occluded coronary artery is treated clinically by rapid re-establishment of perfusion, which is currently viewed as uniquely effective in preventing myocyte cell death. Nevertheless, a body of evidence documents that reperfusion also leads to organ dysfunction, including endothelial and microcirculatory disturbance, arrhythmias, and myocardial stunning. 1 Among the multitude of strategies aiming to prevent ischemiareperfusion (I/R)-induced myocardial detriments, overexpression of the endothelial NO synthase (eNOS) isoform in the myocyte 2 or endothelial 3 compartment has proven recently to be cardioprotective. The endothelial-targeted enhancement of eNOS activity appears particularly promising because it induces vasorelaxation, inhibits platelet aggregation as well as leukocyte recruitment, and antagonizes microcirculatory disturbances. 4 Yet, increase in NO formation by endothelium can exert beneficial effects on the cardiomyocyte compartment, preserving myocyte function by preventing necrosis, 5 apoptosis 6,7 as well as reducing myocyte vulnerability via induction of hibernation. 8 However, the therapeutically desired increase in endothelial NO production does not necessarily require an increase in eNOS abundance because it may also evolve from specific post-translational modifications of endogenously expressed eNOS. Accordingly, the cardioprotective effects of insulin, 6 corticosteroids, 9 and vascular endothelial growth factor (VEGF)...