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Background: Vascular dysfunction is a checkpoint to the development of hypertension. Heparan sulfate proteoglycans (HSPG) participate in nitric oxide (NO) and calcium signaling, key regulators of vascular function. The relationship between HSPG-mediated NO and calcium signaling and vascular dysfunction has not been explored. Likewise, the role of HSPG on the control of systemic blood arterial pressure is unknown. Herein, we sought to determine if the HSPG syndecan 1 and glypican 1 control systemic blood pressure and the progression of hypertension., Purpose: To determine the mechanisms whereby glypican 1 and syndecan 1 regulate vascular tone and contribute to the development of noradrenergic hypertension., Experimental Approach and Key Results: By assessing systemic arterial blood pressure we observed that syndecan 1 (Sdc1 -/- ) and glypican 1 (Gpc1 -/- ) knockout mice show a similar phenotype of decreased systolic blood pressure that is presented in a striking manner in the Gpc1 -/- strain. Gpc1 -/- mice are also uniquely protected from a norepinephrine hypertensive challenge failing to become hypertensive. This phenotype was associated with impaired calcium-dependent vasoconstriction and altered expression of calcium-sensitive proteins including SERCA and calmodulin. In addition, Gpc1 -/- distinctively showed decreased IP 3 R activity and increased calcium storage in the endoplasmic reticulum., Conclusions and Implications: Glypican 1 is a trigger for the development of noradrenergic hypertension that acts via IP 3 R- and calcium-dependent signaling pathways. Glypican 1 may be a potential target for the development of new therapies for resistant hypertension or conditions where norepinephrine levels are increased., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

The severe forms and worsened outcomes of COVID-19 (coronavirus disease 19) are closely associated with hypertension and cardiovascular disease. Endothelial cells express Angiotensin-Converting Enzyme 2 (ACE2), which is the entrance door for the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The hallmarks of severe illness caused by SARS-CoV-2 infection are increased levels of IL-6, C-reactive protein, D-dimer, ferritin, neutrophilia and lymphopenia, pulmonary intravascular coagulopathy and microthrombi of alveolar capillaries. The endothelial glycocalyx, a proteoglycan- and glycoprotein-rich layer covering the luminal side of endothelial cells, contributes to vascular homeostasis. It regulates vascular tonus and permeability, prevents thrombosis, and modulates leukocyte adhesion and inflammatory response. We hypothesized that cytokine production and reactive oxygen species (ROS) generation associated with COVID-19 leads to glycocalyx degradation. A cohort of 20 hospitalized patients with a confirmed COVID-19 diagnosis and healthy subjects were enrolled in this study. Mechanisms associated with glycocalyx degradation in COVID-19 were investigated. Increased plasma concentrations of IL-6 and IL1-β, as well as increased lipid peroxidation and glycocalyx components were detected in plasma from COVID-19 patients compared to plasma from healthy subjects. Plasma from COVID-19 patients induced glycocalyx shedding in cultured human umbilical vein endothelial cells (HUVECs) and disrupted redox balance. Treatment of HUVECs with low molecular weight heparin inhibited the glycocalyx perturbation. In conclusion, plasma from COVID-19 patients promotes glycocalyx shedding and redox imbalance in endothelial cells, and heparin treatment potentially inhibits glycocalyx disruption., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Aim: We determined the role played by O-linked N-acetylglucosamine (O-GlcNAc) of proteins in systemic arteries during late pregnancy in normotensive and hypertensive rats., Main Methods: O-GlcNAc levels and O-GlcNAc modification of endothelial nitric oxide synthase (eNOS) were determined in aorta (conductance vessel) and mesenteric arteries (resistance vessels) of non-pregnant (NP) and pregnant (P) Wistar rats and spontaneously hypertensive rats (SHR). Vascular O-GlcNAc-modified proteins, O-GlcNAcase (OGA) and O-GlcNAc transferase (OGT) expression, and OGA activity were analyzed. Concentration-response to phenylephrine (PE) curves were constructed for arteries with and without endothelium. Arteries were treated with vehicle or PugNAc (OGA inhibitor, 100 μmol/L) in the presence of L-NAME (NOS inhibitor, 100 μmol/L)., Key Findings: The content of vascular O-GlcNAc-modified proteins was lower, OGT and OGA expression did not change, and OGA activity was higher in arteries of P-Wistar rats and P-SHR compared to arteries of NP-groups. Reactivity to PE increased in arteries of P-Wistar rats treated with PugNAc compared to vehicle. O-GlcNAcylation of eNOS decreased in P-SHR compared to NP-SHR. PugNAc partially inhibited the effects of endothelium removal and L-NAME on reactivity to PE in arteries of P-Wistar rats. However, PugNAc did not alter reactivity to PE in arteries of P-SHR. Our data showed that pregnancy decreased the content of vascular O-GlcNAc-modified proteins., Significance: Increased OGA activity and decreased O-GlcNAc modification of eNOS boosts eNOS activity in arteries of P-Wistar rats. In P-SHR, altered OGA activity may lower the content of O-GlcNAc-modified proteins, but decreased OGT activity seems a potential mechanism to reduce glycosylation., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Purpose: This study investigated the intracellular mechanisms involved in the vasodilatation induced by the classic NO donor SNP and the non-classic NO donor cis-[Ru(bpy)2(py)(NO2)](PF6) (or RuBPY) in mesenteric resistance arteries obtained from renal hypertensive (2K-1C) and normotensive (2K) rats., Methods: On the basis of fluorimetric assays in cultured vascular smooth muscle cells (VSMCs) isolated from 2K-1C and 2K rats, we measured NO release from SNP and RuBPY, cytosolic Ca 2+ concentration ([Ca 2+ ]c), and reactive oxygen species (ROS) with the selective probes DAF-2DA, Fluo-3AM and the more selective probe for peroxynitrite (7-CBA), respectively. We determined isometric tension in mesenteric arteries to assess SNP- and RuBPY-induced relaxation., Results: SNP and RuBPY released NO in comparable amounts in cultured aortic VSMCs from hypertensive 2K-1C and normotensive 2K rats. The NO 0 scavenger hydroxocobalamin blunted NO release. Sarco/endoplasmic reticulum Ca 2+ ATPase (SERCA) inhibition with thapsigargin reduced [Ca 2+ ]c in normotensive 2K rat VSMCs only. ROS amounts were greater in hypertensive 2K-1C than in normotensive 2K rat VSMCs, but neither SNP nor RuBPY altered ROS concentrations in any of the groups. SNP and RuBPY induced similar relaxation in hypertensive 2K-1C and normotensive 2K rat mesenteric resistance arteries. The SNP and RuBPY-induced relaxation involves sGC and PKG activation. On the other hand, SNP but not RuBPY activates K + channels. Interestingly, SERCA inhibition reduces SNP induced relaxation only in normotensive 2K rat mesenteric arteries whereas RuBPY-induced relaxation does not involve SERCA activation in both normotensive and hypertensive arteries., Conclusion: Our results indicate that SNP and RuBPY-induced mesenteric resistance artery relaxation involves NO/sGC/cGMP/PKG pathway activation. K + channels and SERCA activation is required to SNP but not for RuBPY-induced relaxation. Moreover, SERCA seems to be impaired in hypertensive 2K-1C rat mesenteric resistance arteries although it does not impact SNP- or RuBPY-induced relaxation., (Copyright © 2019. Published by Elsevier Inc.)

We hypothesized that endothelium modulates relaxation induced by a nitric oxide (NO) donor ruthenium complex (TERPY, [Ru(terpy)(bdq)NO] 3+ ) in mesenteric arteries of normotensive and spontaneously hypertensive (SHR) rats in different ways. We analyzed the mechanism involved in TERPY-induced relaxation in the second and third branches of mesenteric arteries and investigated how endothelium contributes to the TERPY vasodilator effect on SHR blood vessels. TERPY induced concentration-dependent relaxation in endothelium-denuded (E - ) and endothelium-intact (E + ) mesenteric arteries of normotensive rats and SHR. Pretreatment with ODQ (which inhibits soluble guanylyl cyclase) or TEA (tetraethylammonium, which blocks potassium channels) significantly reduced the TERPY vasodilator effect on E - mesenteric arteries of normotensive rats and SHR. The presence of endothelium shifted the concentration-effect curves for TERPY in E + mesenteric arteries of normotensive rats to the right. Conversely, the presence of endothelium shifted the concentration-effect curves for TERPY in the case of SHR E + mesenteric arteries to the left, which suggested increased potency. L-NNA, a more selective endothelial NO synthase (eNOS) inhibitor, reduced TERPY potency in SHR. The presence of endothelium and notably of NOS contributed to the TERPY vasodilator action in SHR: TERPY promoted eNOS Ser 1177 phosphorylation with consequent NO production and increased soluble guanylyl cyclase activity, which may have directly activated potassium channels., (Copyright © 2018. Published by Elsevier Inc.)

Aim: This study aimed to evaluate the effects of Wortmannin, an inhibitor of phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt), on aortic hyporeactivity to Phenylephrine (Phe) and nitric oxide bioavailability associated with pregnancy in hypertensive rats., Main Methods: The intact aortic rings of pregnant and non-pregnant Wistar or spontaneously hypertensive rats (SHRs) were stimulated with Phe (1nmol/L to 10mmol/L) before and after incubation with Wortmannin (10nmol/L, 30min). Western blot experiments analyzed the expression of phosphorylated PI3K [p85-PI3K], Akt [p-Akt (Ser 473)] and eNOS [p-eNOS (Ser 1177)] in aorta homogenates of pregnant and non-pregnant Wistar rats or SHRs. The effect of Wortmannin (10nmol/L) on the cytosolic concentrations of nitric oxide (NO; measured using 4,5-diaminofluorescein diacetate [DAF-2DA], 10mmol/L), Ca(2+) (using Fluo 3-AM, 5μmol/L) and reactive oxygen species (ROS; using dihydroethidium [DHE], 2.5mmol/L) were measured fluorimetrically in freshly isolated endothelial cells., Key Findings: Wortmannin increases the reactivity of the aorta to Phe and decreases NO concentrations in the aortic endothelial cells of pregnant Wistar rats and SHR., Significance: The PI3/AKT/endothelial nitric oxide synthase (eNOS) pathway contributes to aortic hyporeactivity to Phenylephrine associated with pregnancy in normo- and hypertensive rats., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Drugs that release nitric oxide (NO) usually have limitations due to their harmful effects. Sodium nitroprusside (SNP) induces a rapid hypotension that leads to reflex tachycardia, which could be an undesirable effect in patients with heart disease, a common feature of hypertension. The nitrosyl ruthenium complex [Ru(terpy)(bdq)NO(+)](3+) (TERPY) is a NO donor that is less potent than SNP in denuded aortic rings. This study evaluated the hypotension and vasorelaxation induced by this NO donor in Wistar (W) and spontaneously hypertensive rats (SHR) and compared to the results obtained with SNP. Differently from the hypotension induced by SNP, the action of TERPY was slow, long lasting and it did not lead to reflex tachycardia in both groups. The hypotension induced by the NO-donors was more potent in SHR than in W. TERPY induced relaxation with similar efficacy to SNP, although its potency is lower in both strains. The relaxation induced by TERPY is similar in W and SHR, but SNP is more potent and efficient in SHR. The relaxation induced by TERPY is partially dependent on guanylate cyclase in SHR aorta. The NO released from the NO donors measured with DAF-2 DA by confocal microscopy shows that TERPY releases similar amounts of NO in W and SHR, while SNP releases more NO in SHR aortic rings., (Copyright © 2012 Elsevier Inc. All rights reserved.)