Relaxation Of Aorta Research Articles

Fibroblast growth factor 21 reverses high-fat diet-induced impairment of vascular function via the anti-oxidative pathway in ApoE knockout mice.

Circulating endothelial progenitor cells (EPCs), which function in vascular repair, are the markers of endothelial dysfunction and vascular health. Fibroblast growth factor 21 (FGF21), a liver‐secreted protein, plays a crucial role in glucose homeostasis and lipid metabolism. FGF21 has been reported to attenuate the progression of atherosclerosis, but its impact on EPCs under high oxidative stress conditions remains unclear. In vitro studies showed that the β‐klotho protein was expressed in cultured EPCs and that its expression was upregulated by FGF21 treatment. Hydrogen peroxide (H2O2)‐induced oxidative stress impaired EPC function, including cell viability, migration and tube formation. Pretreatment with FGF21 restored the functions of EPCs after the exposure to H2O2. Administration of N(ω)‐nitro‐L‐arginine methyl ester (L‐NAME), an inhibitor of nitric oxide synthase, inhibited the effects of FGF21 in alleviating oxidative injury by suppressing endothelial nitric oxide synthase (eNOS). In an in vivo study, the administration of FGF21 significantly reduced total cholesterol (TC) and blood glucose levels in apolipoprotein E (ApoE)‐deficient mice that were fed a high‐fat diet (HFD). Endothelial function, as reflected by acetylcholine‐stimulated aortic relaxation, was improved after FGF21 treatment in ApoE‐deficient mice. Analysis of mRNA levels in the aorta indicated that FGF21 increased the mRNA expression of eNOS and upregulated the expression of the antioxidant genes superoxide dismutase (SOD)1 and SOD2 in ApoE‐deficient mice. These data suggest that FGF21 improves EPC functions via the Akt/eNOS/nitric oxide (NO) pathway and reverses endothelial dysfunction under oxidative stress. Therefore, administration of FGF21 may ameliorate a HFD‐induced vascular injury in ApoE‐deficient mice.

Inhibition of chemically and mechanically activated Piezo1 channels as a mechanism for ameliorating atherosclerosis with salvianolic acid B.

Salvianolic acid B (SalB) is effective for treating cardiovascular diseases. However, the molecular mechanisms underlying its therapeutic effects remain unclear. Mechanosensitive Piezo1 channels play important roles in vascular biology, although their pharmacological properties are poorly defined. Here, we aimed to identify novel Piezo1 inhibitors and gain insights into their mechanisms of action. Intracellular Ca2+ ions were measured in HUVECs, murine liver endothelial cells (MLECs), THP-1 and RAW264.7 cell lines and bone marrow-derived macrophages (BMDMs). Isometric tensions in mouse thoracic aorta were recorded. Shear-stress assays with HUVECs were conducted. Patch-clamp recordings with mechanical stimulation were performed with HUVECs in whole-cell mode. Foam cell formation was induced by treating BMDMs with oxidised LDL (oxLDL). Atherosclerotic plaque assays were performed with Ldlr-/- and Piezo1 genetically depleted mice on a high-fat diet. Salvianolic acid B inhibited Yoda1-induced Ca2+ influx in HUVECs and MLECs. Similar results were observed in macrophage cell lines and BMDMs. Furthermore, we demonstrated that salvianolic acid B inhibited Yoda1- and mechanically activated currents. Salvianolic acid B suppressed Yoda1-induced aortic ring relaxation and inhibited HUVECs alignment in the direction of shear stress. Additionally, Yoda1 enhanced the formation of foam cells, which was reversed by salvianolic acid B. Salvianolic acid B also inhibited formation of atherosclerotic plaques and was insensitive to Piezo1 genetic depletion. Our study provides novel mechanistic insights into the inhibitory role of salvianolic acid B against Piezo1 channels and improves our understanding of salvianolic acid B in preventing atherosclerotic lesions.

Activation of G protein-coupled estrogen receptor fine-tunes age-related decreased vascular activities in the aortae of female and male rats

BackgroundHormone replacement therapy was found to be effective in cardiovascular protection only in younger women, not in older women. In this study, we tested whether G protein-coupled estrogen receptor 1 (GPER) activation improves vascular activities in response to ET-1 and ACh in aging rats. MethodsIsometric tension study was applied on aortic rings isolated from young adult (5–7 months) and reproductive senescent middle-aged (10–12 months) female Sprague Dawley rats and age matched males. ResultsThe aortic contractile response to ET-1 and the relaxation response to ACh were reduced in the female middle-aged rats compared to the female young adult rats. The presence of G-1, the GPER agonist, normalized the reduced vascular activities. Cyclooxygenase inhibitor, meclofenamate, blocked the increased constriction effect of G-1, but further enhanced relaxation effect of G-1. There was no significant difference in aortic reactivity to either ET-1 or ACh between the male middle-aged and young adult rats. The contractile response to ET-1 was not different within the same age of the two sex groups, but there was a remarkable difference in relaxation response to ACh between young adult females and males with better response in females. GPER activation greatly improved the aortic relaxation of both young adult and middle-aged females, but not the males. ConclusionsEndothelial dysfunction occurs earlier in males, but in females, dysfunction delays until middle age. GPER activation improves the vascular activities in females, but not males. It is promising to employ GPER as a potential drug target in cardiovascular disease in women.

Activin A causes endothelial dysfunction of mouse aorta and human aortic cells.

Preeclampsia is a multisystem hypertensive disorder of pregnancy that remains one of the leading causes of maternal and perinatal morbidity and mortality worldwide. The widespread maternal endothelial dysfunction that underlies preeclampsia is thought to arise from excessive placental production of various factors combined with enhanced oxidative stress. While previous studies have reported elevated activin A in women diagnosed with preeclampsia, whether activin A can cause vascular dysfunction has not yet been thoroughly investigated. Here, we demonstrated that different subtypes of activin A receptors were localised to the endothelial and smooth muscle cells of mouse and human aortae. Then, the aorta of healthy female C57Bl6J mice (n = 8) were incubated for 24 h in various concentrations of recombinant activin A to mimic early pregnancy (5 ng/mL), late pregnancy (20 ng/mL) and preeclampsia (50 ng/mL). Vascular reactivity as assessed by wire myography revealed that only the preeclamptic level of activin A impaired agonist-mediated endothelium-dependent relaxation by reducing the vasodilator prostanoid contribution to relaxation. However, agonist-mediated endothelium-independent mechanisms were unaffected. Further investigations carried out on human aortic endothelial cells suggested that the impairment of aorta relaxation could also be driven by increased endothelial cell permeability, and decreased cell viability, adherence and proliferation. This is the first direct evidence to show that activin A can induce endothelial dysfunction in whole blood vessels, suggesting that at high circulating levels it may contribute to the widespread endothelial dysfunction in women with preeclampsia.

Citronellal alleviate macro- and micro-vascular damage in high fat diet / streptozotocin - Induced diabetic rats via a S1P/S1P1 dependent signaling pathway

Citronellal (CT) is an acyclic monoterpene aldehyde isolated from lemon citronella, which could ameliorate vascular endothelial dysfunction in atherosclerosis in our previous study, however, whether CT can alleviate vascular endothelial dysfunction related with type 2 diabetes (T2DM) is still unknown. So, we investigated the role of CT in vascular dysfunction related to T2DM and the mechanism involved. T2DM rat model was induced by a single intraperitoneal injection of low-dose streptozotocin (STZ) (60 mg/kg) to rats fed with high-fat diet (HFD) (4 weeks). After treated with CT (150 mg/kg/d), both the thoracic aorta injury and micro-vascular pathological injury in T2DM rats ex vivo were alleviated, and the oxidative stress in T2DM rats treated with CT were attenuated, manifested as increased content of endothelial nitric oxide synthase (eNOS) and superoxide dismutase (SOD), and decreased content of malondialdehyde (MDA). Furthermore, CT (15 μg/L) increased the migration capacity of human umbilical vein endothelial cells (HUVECs) under high glucose circumstance (30 mM), and increased the endothelial-dependent relaxation in thoracic aorta isolated from T2DM rats in vitro. Finally, all of these effects of CT were blocked by fingolimod (FTY720), a sphingosine-1-phosphate receptor agonist, and the expression of sphingosine-1-phosphate receptor 1 (S1P1) was increased by CT. In conclusion, CT improved vascular function through S1P/S1P1 signaling pathway.

Hydroxychloroquine induces endothelium-dependent and endothelium-independent relaxation of rat aorta.

Hydroxychloroquine (HCQ) is an antimalarial that is widely used in the management of rheumatoid arthritis and other autoimmune diseases. In this study, we aimed to examine the vascular effects of HCQ on rat aorta (RA). The RA rings were suspended in isolated organ baths and tension was recorded isometrically. HCQ-induced relaxations were tested in the presence of the nitric oxide synthase inhibitor, nitro-L-arginine methyl ester (L-NAME, 100 mM); the cyclooxygenase enzyme inhibitor, indomethacin (10 mM); the calcium (Ca2+) ion channel blocker, nilvadipine (10 μM); and the K+ ion channel inhibitors, tetraethylammonium (1 mM), glibenclamide (10 mM), 4-aminopyridine (1 mM), and barium chloride (30 mM). The effect of HCQ on Ca2+ channels was examined using Ca2+-free Krebs solution, and adding calcium chloride (CaCl2 , 10-5- 10-2 M) cumulatively to baths incubated with HCQ. Removing the endothelium resulted in less relaxation of RA rings compared to endothelium-intact rings (p < 0.05). The effect of endothelium was supported by using L-NAME where HCQ produced-vasorelaxation was decreased (p < 0.05). The contraction of vascular rings was inhibited to a significant degree following the addition of CaCl2 , PE, or KCl on HCQ-incubated RA rings (p < 0.05). The incubation of the RA rings with the Ca2+ channel blocker, the K+ channel blockers, and the COX inhibitor, indomethacin did not significantly affect vascular relaxation induced by HCQ. HCQ produced relaxation of RA rings. The relaxation mechanism differs according to the concentration of HCQ. At con-centrations of 10-6 and 10-5 M, the relaxation is endothelium-dependent and mediated by NO. We strongly suggest that Ca2+ channel inhibition is involved at concentrations of 10-5 and 10-4 M, as well as NO.

Pleiotropic vascular effects of ivabradine in streptozotocin-induced diabetes

AimsIvabradine (IVA) reduces heart rate (HR) by inhibiting hyperpolarization-activated cyclic nucleotide-gated (HCN) channels in sinoatrial node. Studies suggest that IVA has other beneficial effects on cardiovascular system that are not related to its effect on HR such as prevention of endothelial injury and the antioxidant effects. In addition to sinoatrial node, HCN channels exist in other tissues and their expression pattern differs in certain pathologies such as hypertension and hypertrophy. We investigated the mechanism of IVA effect in the setting of streptozotocin (STZ)-induced cardiovascular damage. Direct effects of IVA and their mechanism on thoracic aorta as well as possible prevention of vascular dysfunction in diabetes were investigated in this study. Methods and resultsThe effects of IVA on vascular function were investigated in control and STZ-diabetic rats. Some control and diabetic rats were treated with IVA. IVA treatment prevented diabetes-induced increase in plasma p-selectin and vascular cell adhesion molecule-1 levels and the decrease in nitric oxide content in the aortas of diabetic animals. When added to isolated organ bath, IVA induced concentration-dependent relaxations in thoracic aorta. Pre-incubation with Nω-Nitro- L -arginine methyl ester reduced IVA-induced relaxations. Expression patterns of all isoforms of HCN proteins were affected by both diabetes and IVA treatment. ConclusionIVA improves vascular function in diabetes and HCN channels support vascular activity against damaging effects of diabetes. IVA may be added to prevent diabetic cardiovascular dysfunction with these beneficial effects that are unrelated to its primary mechanism of action.

High dilutions of homeopathic remedies induce relaxation of rat aorta precontracted with Noradrenalin

BACKGROUND&#x0D; Homeopathic potencies have been reported to produce alteration of contraction in isolated rat ileum in an organ bath. Potentized homeopathic drugs like Lycopus V and Aurum met are used for the treatment of hypertension. &#x0D; AIM&#x0D; The purpose of this study is to see whether Lycopus V 30 CH and Aurum met 30 CH could produce relaxation of isolated rat aorta in the organ bath.&#x0D; METHODS&#x0D; The aorta of rats were dissected out, placed in Krebs-Henseleit solution, cleared of connective tissue and endothelium and cut into 2-2.5 mm long rings. The rings were fixed in organ baths with the upper end connected by a string to an isometric transducer which was finally attached through a data acquisitation equipment to a computer. Aurum met 30 CH Lycopus V 30 CH, and their medium 90% ethanol were added separately to the bathing fluid containing the aorta rings which were precontracted with noradrenalin (NA).&#x0D; RESULTS&#x0D; Both the drugs produced significant relaxation of the aorta (p

Identification of Piezo1 channels in perivascular adipose tissue (PVAT) and their potential role in vascular function

The vasculature constantly experiences distension/pressure exerted by blood flow and responds to maintain homeostasis. We hypothesized that activation of the stretch sensitive, non-selective cation channel Piezo1 would directly increase vascular contraction in a way that might be modified by perivascular adipose tissue (PVAT). The presence and function of Piezo1 was investigated by RT-PCR, immunohistochemistry, and isolated tissue bath contractility. Superior and mesenteric resistance arteries, aortae, and their PVATs from male Sprague Dawley rats were used. Piezo1 mRNA was detected in aortic vessels, aortic PVAT, mesenteric vessels, and mesenteric PVAT. Both adipocytes and stromal vascular fraction of mesenteric PVAT expressed Piezo1 mRNA. In PVAT, expression of Piezo1 mRNA was greater in magnitude than that of Piezo2, transient receptor potential cation channel, subfamily V, member 4 (TRPV4), anoctamin 1, calcium activated chloride channel (TMEM16), and Pannexin1 (Panx1). Piezo1 protein was present in endothelium and PVAT of rat aortic and in PVAT of mesenteric artery. The Piezo1 agonists Yoda1 and Jedi2 (1 nM - 10 µM) did not stimulate aortic contraction [max < 10% phenylephrine (PE) 10 µM contraction] or relaxation in tissues + or -PVAT. Depolarizing the aorta by modestly elevated extracellular K+ did not unmask aortic contraction to Yoda1 (max <10% PE 10 µM contraction). Finally, the Piezo1 antagonist Dooku1 did not modify PE-induced aorta contraction + or -PVAT. Surprisingly, Dooku1 directly caused aortic contraction in the absence (Dooku1 =26 ± 11; Vehicle = 11 ± 11%PE contraction) but not in the presence of PVAT (Dooku1 = 2 ± 1; Vehicle = 8 ± 5% PE contraction). Thus, Piezo1 is present and functional in the isolated rat aorta but does not serve direct vascular contraction with or without PVAT. We reaffirmed the isolated mouse aorta relaxation to Yoda1, indicating a species difference in Piezo1 activity between mouse and rat.

Perivascular adipose tissue-derived nitric oxide compensates endothelial dysfunction in aged pre-atherosclerotic apolipoprotein E-deficient rats

Background and aimsAtherosclerosis is a major contributor to global mortality and is accompanied by vascular inflammation and endothelial dysfunction. Perivascular adipose tissue (PVAT) is an established regulator of vascular function with emerging implications in atherosclerosis. We investigated the modulation of aortic relaxation by PVAT in aged rats with apolipoprotein E deficiency (ApoE−/−) fed a high-fat diet as a model of early atherosclerosis. Methods and resultsApoE−/− rats (N = 7) and wild-type Sprague-Dawley controls (ApoE+/+, N = 8) received high-fat diet for 51 weeks. Hyperlipidemia was confirmed in ApoE−/− rats by elevated plasma cholesterol (p < 0.001) and triglyceride (p = 0.025) levels. Early atherosclerosis was supported by increased intima/media thickness ratio (p < 0.01) and ED1-positive macrophage influx in ApoE−/− aortic intima (p < 0.001). Inflammation in ApoE−/− PVAT was characteristic by an increased [18F]FDG uptake (p < 0.01), ED1-positive macrophage influx (p = 0.0003), mRNA expression levels of CD68 (p < 0.001) and IL-1β (p < 0.01), and upregulated iNOS protein (p = 0.011). The mRNAs of MCP-1, IL-6 and adiponectin remained unchanged in PVAT. Aortic PVAT volume measured with micro-PET/CT was increased in ApoE−/− rats (p < 0.01). Maximal endothelium-dependent relaxation (EDR) to acetylcholine in ApoE−/− aortic rings without PVAT was severely impaired (p = 0.012) compared with controls, while ApoE−/− aortic rings with PVAT showed higher EDR than controls. All EDR responses were blocked by L-NMMA and the expression of eNOS mRNA was increased in ApoE−/− PVAT (p = 0.035). ConclusionUsing a rat ApoE−/− model of early atherosclerosis, we capture a novel mechanism by which inflammatory PVAT compensates severe endothelial dysfunction by contributing NO upon cholinergic stimulation.

Abstract 10955: The Effects of Acute and Chronic Selective Phosphodiesterase 1 Inhibition in Associated Smooth Muscle Cell-Specific Aging Features

Introduction: Aging-related vascular smooth muscle cell (VSMC) remodeling plays an essential role in cardiovascular diseases. Reduced NO-cGMP pathway signalling is a major feature and pathogenic mechanism underlying VSMC dysfunction. Recently, we found that phosphodiesterase (PDE) 1, an enzyme that hydrolyzes and inactivates the cyclic nucleotides cAMP and cGMP, is a potential treatment target for restoring age-related deficits in VSMC signalling. We here tested the effects of PDE1 inhibition in SMC-specific Ercc1 DNA repair mutant mice, a model of isolated, accelerated SMC aging. Design and Method: SM22α Cre+ Ercc1 fl/- (SMC-KO) and SM22α Cre+ Ercc1 fl/+ littermate (SMC-LM) mice receive either vehicle or the PDE1 inhibitor lenrispodun (dose 40mg/kg/day) in drinking water for 8 weeks. Reactive hyperemia was measured in-vivo at the age of 14 and 25 weeks. Mice were sacrificed at 26 weeks. The endothelium-dependent (ED) and -independent (EI) relaxation of the thoracic aorta was assessed by wire myography. Moreover, we investigated the effect of PDE1 inhibition on the expression of selected PDEs involved in the vasculature by qPCR. Results: Reactive hyperemia was dramatically reduced in vehicle-treated SMC-KO vs. SMC-LM at the age of 25 weeks (P=0.0002) but was preserved in lenrispodun-treated SMC-KO mice. In vehicle-treated SMC-KO mice, the ED and EI relaxations were greatly diminished compared to SMC-LM (ED: 23.92±4.34 vs. 68.04±4.86, P&lt;0.0001; EI: 57.93±5.31 vs. 87.43±4.01, P=0.0004). Acute administration of lenrispodun in the organ bath improved both ED and EI responses (ED: 38.61±4.04, P=0.001; EI 69.99±4.29 P=0.01) while the relaxations remained unchanged after chronic lenrispodun treatment. In addition, lenrispodun upregulated PDE1a mRNA expression in SMC-KO, while no changes were observed in other PDEs. Conclusions: PDE1 inhibition may therapeutically be useful in restoring age-related vascular dysfunction by preserving microvascular function and potentiating NO-cGMP signaling. Yet, its chronic effects might be counteracted by the upregulation of PDE1a in vasculature. These results warrant further pharmacodynamic profiling of PDE enzyme regulation during chronic PDE1 inhibitor treatment.

Ethyl Acetate Fraction from Leandra dasytricha (A. Gray) Cong. Leaves Promotes Vasodilatation and Reduces Blood Pressure in Normotensive and Hypertensive Rats.

Leandra dasytricha (A. Gray) Cong. is widely distributed in the south of Brazil and is commonly used for cardiovascular and kidney ailments. For this study, we used male Wistar normotensive rats (NTRs) and spontaneously hypertensive rats (SHRs) to verify the effects of the ethyl acetate fraction (EAF) obtained from L. dasytricha leaves on isolated aorta relaxation and in the arterial blood pressure. The EAF was analyzed by LC-DAD-MS, and several components were annotated, including hydrolysable tannins, triterpenes, and O- and C-glycosylated dihydrochalcones, such as the most intense ion peak relative to C-hexosyl phloretin (nothofagin; compound number 13). The EAF caused a concentration and endothelium-dependent relaxation of the aorta in both NTRs and SHRs. This effect was abolished in the endothelium-denuded aorta. L-NAME, a nonselective nitric oxide synthase inhibitor, and ODQ, a soluble guanylate cyclase inhibitor, entirely blocked the EAF-induced relaxation. The presence of a muscarinic receptor antagonist or a cyclooxygenase inhibitor did not alter the EAF's effectiveness in relaxing the aorta. The preincubation with tetraethylammonium, a Ca2+-activated K+ channel blocker, and with 4-aminopyridine, a voltage-dependent K+ channel blocker, significantly interfered with the EAF's relaxation. However, the incubation with glibenclamide, an ATP-sensitive K+ channel blocker, and barium chloride, an inward-rectifier K+ channel blocker, did not interfere with the EAF-induced relaxation. The EAF treatment also caused a dose-dependent decrease in the mean arterial pressure, systolic arterial pressure, and diastolic arterial pressure of both NTRs and SHRs, without significantly interfering with heart rate values. In conclusion, this study demonstrated the EAF-induced vasorelaxant and hypotensive actions, primarily dependent on the endothelium function and mainly with the participation of the nitric oxide and Ca2+-activated and voltage-dependent K+ channels.

Endothelial dysfunction caused by circulating microparticles from diabetic mice is reduced by PD98059 through ERK and ICAM-1

Endothelial dysfunction contributes to the development of diabetic complications and the production of circulating microparticles (MPs). Our previous study showed that diabetic mice-derived MPs (DM MPs) had increased levels of extracellular regulated protein kinase 1/2 (ERK1/2) and impaired endothelial-dependent relaxation in aortas when compared with control mice-derived MPs. This study was designed to investigate whether PD98059, an ERK1/2 inhibitor, affects the function of aortas and DM MPs. MPs were obtained from streptozotocin-induced DM, DM after PD98059 treatment, and ICR mice as control. The mice and MPs were then analyzed on the basis of their vascular function and enzyme expressions. Compared with the controls, platelet-derived MPs and ERK1/2 levels in the MPs were significantly elevated in the DM but showed little change in PD98059-treated DM. PD98059 mainly decreased ERK1/2 phosphorylation in the MPs. In the aortas of DM and DM MPs the endothelium-dependent vascular function was impaired, and there was a significantly greater improvement in the vascular function in the PD98059-treated DM aortas and the aortas treated with PD98059-treated DM MPs than in DM aortas and the aortas treated with DM MPs. Furthermore, DM MPs increased ERK1/2 and intracellular adhesion molecule-1 (ICAM-1) expressions in the aortas, but PD98059-treated DM MPs did not show these effects. For the first time, these results indicate that PD98059 treatment improves endothelial dysfunction in DM, and adhesion properties of DM MPs can be partly blocked by PD98059 via ERK and ICAM-1. These effects may explain some of the vascular complications in diabetes.

INOS regulates activation of the NLRP3 inflammasome through the sGC/cGMP/PKG/TACE/TNF-α axis in response to cigarette smoke resulting in aortic endothelial pyroptosis and vascular dysfunction

BackgroundCigarette smoke (CS) is associated with vascular injury and dysfunction, which may be mediated by iNOS and NLRP3. However, the exact mechanism is unknown. MethodsiNOS-knockout and NLRP3-knockout C57BL/6 mice were exposed to air or CS. The vascular structure was examined by hematoxylin-eosin staining. The vascular tension was measured by a vascular reactivity assay. The expression of iNOS, NLRP3, caspase-1p20, IL-1β and eNOS were measured by western blotting. Human aortic endothelial cells (HAECs) were exposed to L-NIL (iNOS inhibitor), MCC950 (NLRP3 inhibitor), ODQ (sGC inhibitor), KT5823 (PKG inhibitor) or TAPI-1 (TACE/ADAM17 inhibitor) for 1 h prior to cigarette smoke extract (CSE) treatment. The cell viability and lactate dehydrogenase activity were assessed and pyroptosis was determined by scanning electron microscopy. The mRNA expression of TNF-α, and protein expression of iNOS, active-TACE, NLRP3, caspase-1p20, IL-1β, and eNOS were measured. ResultsCS resulted in shrinkage of endothelial cells, impaired aorta relaxation, reduced eNOS expression, and induced expression of iNOS, NLRP3, caspase-1p20 and IL-1β, which could be prevented by knockdown of iNOS and NLRP3. CSE reduced cell viability, induced LDH release and pyroptosis, and promoted iNOS, NLRP3, caspase-1p20, and IL-1β expression and reduced eNOS reduction, which could be reversed by inhibition of iNOS or NLRP3 in HAECs. Altogether, activation of the NLRP3 inflammasome by iNOS in CS-exposed HAECs may be mediated by the sGC/cGMP/PKG/TACE/TNF- α pathway. ConclusionThese results link iNOS to NLRP3 in CSE-stimulated HAECs through the sGC/cGMP/PKG/TACE/TNF-α pathway. The findings identify a mechanism through which iNOS and NLRP3 contribute to the pathogenesis of CS-induced pyroptosis and impaired aorta relaxation in HAECs.

Relaxin Attenuates Organ Fibrosis via an Angiotensin Type 2 Receptor Mechanism in Aged Hypertensive Female Rats.

The antifibrotic effects of recombinant human relaxin (RLX) in the kidney are dependent on an interaction between its cognate receptor (RXFP1) and the angiotensin type 2 receptor (AT2R) in male models of disease. Whether RLX has therapeutic effects, which are also mediated via AT2R, in hypertensive adult and aged/reproductively senescent females is unknown. Thus, we determined whether treatment with RLX provides cardiorenal protection via an AT2R-dependent mechanism in adult and aged female stroke-prone spontaneously hypertensive rats (SHRSPs). In 6-month-old (6MO) and 15-month-old ([15MO]; reproductively senescent) female SHRSP, systolic BP (SBP), GFR, and proteinuria were measured before and after 4 weeks of treatment with vehicle (Veh), RLX (0.5 mg/kg per day s.c.), or RLX+PD123319 (AT2R antagonist; 3 mg/kg per day s.c.). Aortic endothelium-dependent relaxation and fibrosis of the kidney, heart, and aorta were assessed. In 6MO SHRSP, RLX significantly enhanced GFR by approximately 25% (P=0.001) and reduced cardiac fibrosis (P=0.01) as compared with vehicle-treated counterparts. These effects were abolished or blunted by PD123319 coadministration. In 15MO females, RLX reduced interstitial renal (P=0.02) and aortic (P=0.003) fibrosis and lowered SBP (13±3 mm Hg; P=0.04) relative to controls. These effects were also blocked by PD123319 cotreatment (all P=0.05 versus RLX treatment alone). RLX also markedly improved vascular function by approximately 40% (P<0.001) in 15MO SHRSP, but this was not modulated by PD123319 cotreatment. The antifibrotic and organ-protective effects of RLX, when administered to a severe model of hypertension, conferred cardiorenal protection in adult and reproductively senescent female rats to a great extent via an AT2R-mediated mechanism.

Combined antihypertensive effect of unripe Rubus coreanus Miq. and Dendropanax morbiferus H. L\xe9v. Extracts in 1 kidney-1 clip hypertensive rats and spontaneously hypertensive rats

BackgroundWe previously showed that enzymatically hydrolyzed Dendropanax morbiferus H. Lév. leaf (Hy-DP) and unripe Rubus coreanus Miq. (5-uRCK) extracts exhibit potent vasodilator effects on isolated aortic rings from rats partly through endothelium-dependent and endothelium-independent mechanisms. These two extracts have different mechanisms of action; however, their combined effect on antihypertensive activity has not been explored.MethodsThe present study aims to investigate the effect of a chronic optimized mixture (HDR-2, composed of Hy-DP and 5-uRCK in a 2:1 mass ratio) on vascular tension and blood pressure in two different hypertensive rat models.ResultsThe results showed that HDR-2 concentration-dependently relaxed endothelium-intact and endothelium-denuded aortic rings precontracted with phenylephrine. Antihypertensive effects were assessed in vivo on a 1 kidney-1 clip (1 K-1C) rat model of hypertension and spontaneously hypertensive rats (SHRs). Acute HDR-2 treatment significantly decreased systolic blood pressure (SBP) 3 h posttreatment in both models. Chronic HDR-2 administration also significantly decreased SBP in the hypertensive rat models. Moreover, HDR-2 increased eNOS protein expression and phosphorylation levels in the aorta.ConclusionChronic HDR-2 administration may effectively improve vascular function by decreasing plasma angiotensin-converting enzyme (ACE) activity and AngII levels. HDR-2 significantly improved acetylcholine (ACh)-induced aortic endothelium-dependent relaxation and affected sodium nitroprusside (SNP)-induced endothelium-independent relaxation in SHRs.

Acute induction of psoriasis-like skin inflammation disturbes vascular tone and provokes a rapid blood pressure response in mice

Abstract Background Psoriasis is the most common chronic skin disease worldwide. Furthermore, it is an independent cardiovascular risk factor. Several genetic and inducible murine models reproduce specific aspects of the human disease. In mice genetically overexpressing IL-17A in keratinocytes or dendritic cells, we coulod show both aspects of the disease: cutaneous hallmarks and the vascular phenotype. The most popular inducible model consists of topical application of Imiquimod (IMQ), a Toll-like receptor 7/8 agonist. In this model, cardiovascular aspects have not been studied yet. Therefore, we examined vascular and hemodynamic effects in this most popular murine psoriasis model. Methods C57BL/6J mice were treated with 5% IMQ or sham cream. During treatment, we measured bodyweight, skin thickness and skin water loss. After 10 days, aortic relaxation studies were performed. For assessment of vascular inflammation, inflammatory cell infiltration into the aortic tissue was investigated by flow cytometric analysis. To record physical activity, blood pressure and heart rate, carotid catheters were implanted two weeks before treatment with IMQ. Blood pressure and heart rate were continuously recorded by receiver platforms. Results IMQ treatment resulted in severe skin inflammation and induced a skin barrier defect resulting in a 7-fold increase of transcutaneous water loss (from 11±6 ml/m2h to 77±30 ml/m2h). Physical activity decreased more than 50% after d1 of treatment and normalized at d7. Telemetric recording revealed a reflex tachycardia at 1d of IMQ-application (from 492±21 bpm to 524±20 bpm) followed by a significant reduction of heart rate for the next two days (456±18bpm). Systolic blood pressure showed a similar trend: after a fast increase (from 120±13 mmHg to 127±18 mmHg), blood pressure dropped below baseline at d2/3 with a subsequent recovery. We could display a highly significant positive correlation between blood pressure and heart rate during the treatment (R=0.6; p≤0.0001). Aortas from animals after 10d of IMQ-treatment showed an increased infiltration of CD45+ and CD11b+ inflammatory cells but no change of responsiveness to endothelium dependent and independent vasodilators in organ chamber studies. Conclusion Skin treatment with IMQ had severe implications on the hemodynamic system: After an initial peak of heart rate and blood pressure, mice showed significantly lower values for two days with a subsequent full recovery. Moreover, bodyweight and physical activity were significantly altered during treatment. Our data indicate that skin inflammation and inflammatory skin barrier disruption by IMQ forces a compensatory whole-body response. 10 days of IMQ-treatment resulted in vascular inflammation without mediating vascular dysfunction. In summary, we could reveal that IMQ-induced psoriasis, as the most popular murine psoriasis model worldwide, has extensive effects on the cardiovascular system. Funding Acknowledgement Type of funding sources: Foundation. Main funding source(s): Boehringer Ingelheim Foundation “Novel and neglected cardiovascular risk factors: molecular mechanisms and therapeutic implications”German Federal Ministry for Education and Research (BMBF EDU-V24)

Intrauterine and Lactational Exposure to Paracetamol: Cardiometabolic Evaluation in Adult Female and Male Offspring.

Paracetamol (PAR) is the most common over-the-counter drug recommended by physicians for treatment of pain and fever during gestation. This drug is not teratogenic, being considered safe for fetus; however, PAR crosses the blood-placental barrier. Considering that, the present study aimed to evaluate the vascular and metabolic safety of PAR exposure during intrauterine and neonatal development in adult male and female-exposed offspring. Wistar female rats were gavaged, with PAR (350 mg/kg/d), from gestational day 6-21 or from gestational day 6 until postnatal day 21. Control dams received water by gavage at the same periods. The male and female offspring were evaluated at adulthood (80 days of life). The thoracic aorta reactivity to acetylcholine, sodium nitroprusside, and phenylephrine was evaluated in male and female adult offspring. It was observed that aortic relaxation was similar between the PAR and control offspring. In addition, the contraction to phenylephrine was similar between the groups. Further, the insulin sensitivity, adipose tissue deposition and blood pressure were not different between PAR and control adult offspring. These results suggest that the protocol of PAR exposure used in the present study did not program vascular and metabolic alterations that would contribute to the development of cardiometabolic diseases in adult life, being safe for the exposed offspring.

Abstract P274: Inhibition Of Abnormal Exosome Release Prevents Excessive Aortic Stiffness And Relaxation Dysfunction In Diet-induced Obesity

Interactions between over-nutrition and abnormal exosome release impact insulin sensitivity and the development of cardiovascular disease (CVD). Recent data have shown that exosomes can be released from various cell types, including adipocytes and vascular cells, and that they exist in body fluids and tissues functioning as mediators of cell-cell communication. However, the specific role of exosomes in diet-induced excessive vascular stiffness and hypertension has not been explored. Accordingly, we hypothesized that abnormal release of exosomes contributes to western diet (WD)- induced aortic stiffening and impaired vascular diastolic relaxation. We further posited that GW4869, an antagonist of neutral sphingomyelinase 2 (nSMase2) which promotes exosome production and release, would prevent WD-induced aortic stiffening and impaired vascular relaxation. Six week-old female C57BL/6L mice were fed a mouse chow (CD) or WD containing excess fat (46%) and fructose (17.5%) for 16 weeks with or without GW4849. To this point, 200 μl of 0.3 mg/mL GW4869 in 0.9% normal saline (60 μg/mouse; 2-2.5 μg/g body weight) was injected intraperitoneally every 48 hours for 12 weeks. 16 weeks of WD induced an increase of aortic stiffness as examined by pulse wave velocity (PWV) and impaired the aortic vasodilation responses to acetylcholine (Ach) and sodium nitroprusside (SNP) (10 -9 -10 -4 mol/L). However, GW4869 treatment prevented the WD-induced excessive aortic stiffness, as well as impairment of endothelium dependent/independent vascular relaxation. There were no significant differences in blood pressure between each group examined by tail cuff blood pressure measurement. These findings support the hypothesis that abnormal release of exosomes play an important role in WD-induced excessive aortic stiffness, impaired vascular relaxation and CVD in diet-induced obesity.

Abstract 03: Ablation Of Endothelial Dysfunction Improves Blood Pressure And Fetal Growth Restriction In A Mouse Model Of Preeclampsia-like Hyperleptinemia

Placental ischemia, an initiating event of preeclampsia (PE), increases plasma leptin levels. We recently developed a model of midgestation (gestation day (GD)11-18) leptin infusion mimicking the midgestation rise in leptin levels of PE patients. Our previous work demonstrates that deletion of endothelial mineralocorticoid receptors (ECMR) improves markers of vascular dysfunction in leptin-infused female mice. We hypothesized vascular function improvement with ECMR deletion ablates hypertension and fetal growth restriction in pregnant leptin-infused mice. Pregnant ECMR +/+ (WT) and ECMR -/- (KO) mice were infused with vehicle or leptin by osmotic pump (lep, 0.9mg/kg/day, s.c.) on GD11-18 while implanted with radiotelemeters for conscious blood pressure (BP) measurement and wire myography of thoracic aorta and 2 nd order mesenteric arteries at GD18 (*=P&lt;0.05). Leptin infusion did not decrease maternal weight in any groups. Leptin decreased pup weight (0.86±0.04g WT vs 0.52±0.11 WT+lep*) and placental efficiency (pup/placenta ratio) (9.7±0.7 WT vs 7.9±0.6 WT+lep*) in WT pregnant mice. ECMR deletion prevented leptin-mediated decreases in pup weight (0.91±0.06g KO vs 1.0±0.07 KO+lep) and placental efficiency (9.6±0.5 KO vs 9.4±1.2 KO+lep). Mean arterial pressure (BP) increased in leptin-infused WT (102±3mmHg WT vs 120±12 WT+lep*), but not KO (107±2 KO vs 106±8 KO+lep), mice from GD11-18. Leptin infusion reduced acetylcholine-mediated relaxation in both aorta and mesenteric arteries of WT* and constriction to KCl in mesenteric arteries in WT*, but not KO, pregnant mice (2-way ANOVA, repeated measures). Leptin increased plasma endothelin-1 (ET-1, 1.1±0.3 pg/ml WT vs 4.4±1.8 WT+lep*), placental mRNA expression of prepro-ET-1 (1.9±0.3-fold change from WT*) and ET-1 converting enzyme-1 (1.6±0.3-fold change from WT*) in pregnant WT mice. Leptin infusion also increased adrenal aldosterone-synthase protein (1.4±0.4 WT ratio/β actin vs 3.2±0.3 WT+lep*) and angiotensin II type 1 receptor b (3.5±0.8-fold change from WT*) mRNA in pregnant mice. Collectively, these data indicate that leptin infusion induces hypertension and fetal growth restriction in pregnant mice due to vascular dysfunction and increased ECMR activation in pregnant mice.