Sex-specific differences in the mechanisms for enhanced thromboxane A2-mediated vasoconstriction in adult offspring exposed to prenatal hypoxia.

BACKGROUND: Prenatal hypoxia, a common pregnancy complication, leads to impaired cardiovascular outcomes in the adult offspring. It results in impaired vasodilation in coronary and mesenteric arteries of the adult offspring, due to reduced nitric oxide (NO). Thromboxane A2 (TxA2) is a potent vasoconstrictor increased in cardiovascular diseases, but its role in the impact of prenatal hypoxia is unknown. To prevent the risk of cardiovascular disease by prenatal hypoxia, we have tested a maternal treatment using a nanoparticle-encapsulated mitochondrial antioxidant (nMitoQ). We hypothesized that prenatal hypoxia enhances vascular TxA2 responses in the adult offspring, due to decreased NO modulation, and that this might be prevented by maternal nMitoQ treatment. METHODS: Pregnant Sprague-Dawley rats received a single intravenous injection (100 µL) of vehicle (saline) or nMitoQ (125 µmol/L) on gestational day (GD)15 and were exposed to normoxia (21% O2) or hypoxia (11% O2) from GD15 to GD21 (term = 22 days). Coronary and mesenteric arteries were isolated from the 4-month-old female and male offspring, and vasoconstriction responses to U46619 (TxA2 analog) were evaluated using wire myography. In mesenteric arteries, L-NAME (pan-NO synthase (NOS) inhibitor) was used to assess NO modulation. Mesenteric artery endothelial (e)NOS, and TxA2 receptor expression, superoxide, and 3-nitrotyrosine levels were assessed by immunofluorescence. RESULTS: Prenatal hypoxia resulted in increased U46619 responsiveness in coronary and mesenteric arteries of the female offspring, and to a lesser extent in the male offspring, which was prevented by nMitoQ. In females, there was a reduced impact of L-NAME in mesenteric arteries of the prenatal hypoxia saline-treated females, and reduced 3-nitrotyrosine levels. In males, L-NAME increased U46619 responses in mesenteric artery to a similar extent, but TxA2 receptor expression was increased by prenatal hypoxia. There were no changes in eNOS or superoxide levels. CONCLUSIONS: Prenatal hypoxia increased TxA2 vasoconstrictor capacity in the adult offspring in a sex-specific manner, via reduced NO modulation in females and increased TP expression in males. Maternal placental antioxidant treatment prevented the impact of prenatal hypoxia. These findings increase our understanding of how complicated pregnancies can lead to a sex difference in the programming of cardiovascular disease in the adult offspring.

Prenatal hypoxia, when the fetus does not receive enough oxygen, is a common problem during pregnancy that impacts the developing fetus. It is associated with an increased risk of cardiovascular disease in the offspring in adulthood. While the mechanisms are not fully understood, the blood vessel function in the offspring may be impacted by prenatal hypoxia. We hypothesize that prenatal hypoxia increases the constriction of the blood vessels in the offspring. The placenta, an essential organ for fetal development, supplies oxygen and nutrients to the fetus. In prenatal hypoxia pregnancies, the placenta does not work properly. We have been studying a placental treatment (called nMitoQ) to improve placenta function and thereby the blood vessel function of the offspring. We used a rat model of prenatal hypoxia, where pregnant rats (dams) were placed in a low oxygen environment (hypoxia) during the last trimester of pregnancy. Control rats were kept in normal oxygen conditions. The dams were treated with nMitoQ, or with saline (control). Next, we studied the blood vessels of the offspring in adulthood. We found that prenatal hypoxia increases the constriction of the blood vessels, which was prevented by treating the dams with nMitoQ. Interestingly, this impact was more severe in females compared to males, and the mechanisms were different between the sexes. This study helps in the understanding of how complicated pregnancies can impair cardiovascular health in the offspring, and in a potential development of targeted and sex-specific therapies for those offspring at high risk for future cardiovascular disease.

Niclosamide potentiates TMEM16A and induces vasoconstriction.

The TMEM16A calcium-activated chloride channel is a promising therapeutic target for various diseases. Niclosamide, an anthelmintic medication, has been considered a TMEM16A inhibitor for treating asthma and chronic obstructive pulmonary disease (COPD) but was recently found to possess broad-spectrum off-target effects. Here, we show that, under physiological Ca2+ (200-500 nM) and voltages, niclosamide acutely potentiates TMEM16A. Our computational and functional characterizations pinpoint a putative niclosamide binding site on the extracellular side of TMEM16A. Mutations in this site attenuate the potentiation. Moreover, niclosamide potentiates endogenous TMEM16A in vascular smooth muscle cells, triggers intracellular calcium increase, and constricts the murine mesenteric artery. Our findings advise caution when considering clinical applications of niclosamide as a TMEM16A inhibitor. The identification of the putative niclosamide binding site provides insights into the mechanism of TMEM16A pharmacological modulation and provides insights into developing specific TMEM16A modulators to treat human diseases.

How three linked clinical observations led to an understanding of perioperative heat balance: A personal reflection on the scientific process.

Three linked clinical observations prompted our current understanding of perioperative heat balance. The first was the extraordinarily rapid decrease in core temperature after induction of general anesthesia which led to an understanding of redistribution hypothermia. The second was the linear reduction in core temperature during the subsequent 2-3 h which led to an understanding of anesthetic effects on metabolic heat production and factors that influence cutaneous heat loss. And the third was the observation that core temperature reaches a plateau at about 34.5 °C which led to the understanding that thermoregulatory vasoconstriction re-emerges when patients become sufficiently hypothermic, and that arteri-venous shunt constriction constrains metabolic heat to the core thermal compartment.

Chronic sarpogrelate treatment improves renal sympathetic hyperactivity in experimental diabetes.

Diabetes and derived complications, especially diabetic nephropathy and neuropathy annually cause great morbimortality worldwide. 5-hydroxytryptamine (5-HT) acts as a modulator of renal sympathetic input and vascular tone. In this line, 5-HT2 receptor blockade has been linked with reduced incidence and progression of diabetic microvascular alterations. In this work, we aimed to determine, in diabetic rats, whether 5-HT2 blockade ameliorates renal function and to characterize the serotonergic modulatory action on renal sympathetic neurotransmission. Diabetes was induced in male Wistar rats by alloxan administration (150 mg/kg, s.c.), and sarpogrelate (30 mg/kg·day, p.o.; 5-HT2 antagonist) was administered for 14 days (DM-S). Normoglycemic and diabetic (DM) animals were maintained as aged-matched controls. At 28th day, DM-S animals were anesthetized and prepared for the in situ autoperfusion of the kidney. Renal vasoconstrictor responses were induced electrically or by i.a. noradrenaline (NA) administration. The role of 5-HT and selective 5-HT agonist/antagonist were studied on these renal vasopressor responses. Sarpogrelate treatment decreased renal sympathetic-induced vasopressor responses, reduced renal hypertrophy and kidney damage markers increased in DM. Intraarterial 5-HT inhibited the sympathetic-induced renal vasoconstrictions, effect reproduced by 5-CT, AS-19, L-694,247 and LY 344864 (5-HT1/5/7, 5-HT7, 5-HT1D and 5-HT1F receptor agonists, respectively). Blocking 5-HT1D/1F/7 receptors completely abolished the 5-CT sympatho-inhibition. NA vasoconstrictions were not altered by any of the 5-HT agonists tested. Thus, in experimental diabetes, chronic sarpogrelate treatment reduces renal damage markers, kidney hypertrophy and renal sympathetic hyperactivity and modifies serotonergic modulation of renal sympathetic neurotransmission, causing a sympatho-inhibition by prejunctional 5-HT1D/1F and 5-HT7 activation.

Prenatal High-Sucrose Diet Induced Vascular Dysfunction of Renal Interlobar Arteries in the Offspring via PPARγ-RXRg-ROS/Akt Signaling.

SCOPE: Prenatal nutrition imbalance correlates with developmental origin of cardiovascular diseases; however whether maternal high-sucrose diet (HS) during pregnancy causes vascular damage in renal interlobar arteries (RIA) from offspring still keeps unclear. METHODS AND RESULTS: Pregnant rats are fed with normal drinking water or 20% high-sucrose solution during the whole gestational period. Swollen mitochondria and distributed myofilaments are observed in vascular smooth muscle cells of RIA exposed to prenatal HS. Maternal HS increases phenylephrine (PE)-induced vasoconstriction in the RIA from adult offspring. NG-Nitro-l-arginine (L-Name) causes obvious vascular tension in response to PE in offspring from control group, not in HS. RNA-Seq of RIA is performed to reveal that the gene retinoid X receptor g (RXRg) is significantly decreased in the HS group, which could affect vascular function via interacting with PPARγ pathway. By preincubation of RIA with apocynin (NADPH inhibitor) or capivasertib (Akt inhibitor), the results indicate that ROS and Akt are the vital important factors to affect the vascular function of RIA exposure to prenatal HS. CONCLUSION: Maternal HS during the pregnancy increases PE-mediated vasoconstriction of RIA from adult offspring, which is mainly related to the enhanced Akt and ROS regulated by the weakened PPARγ-RXRg.

Vascular Response of Triiodothyronine on Isolated Aortic Rings: Contribution of Redox Mechanisms. / Resposta Vascular da Triiodotironina sobre Anéis de Aortas Isoladas: Contribuição de Mecanismos Redox.

BACKGROUND: Vascular dysfunction constitutes the etiology of many diseases, such as myocardial infarction and hypertension, with the disruption of redox homeostasis playing a role in the imbalance of the vasomotor control mechanism. Our group previously has shown that thyroid hormones exert protective effects on the aortic tissue of infarcted rats by improving angiogenesis signaling. OBJECTIVE: Investigate the role of triiodothyronine (T3) on vascular response, exploring its effects on isolated aortas and whether there is an involvement of vascular redox mechanisms. METHODS: Isolated aortic rings (intact- and denuded-endothelium) precontracted with phenylephrine were incubated with T3 (10-8, 10-7, 10-6, 10-5, and 10-4 M), and tension was recorded using a force-displacement transducer coupled with an acquisition system. To assess the involvement of oxidative stress, aortic rings were preincubated with T3 and subsequently submitted to an in vitro reactive oxygen species (ROS) generation system. The level of significance adopted in the statistical analysis was 5%. RESULTS: T3 (10-4 M) promoted vasorelaxation of phenylephrine precontracted aortic rings in both intact- and denuded-endothelium conditions. Aortic rings preincubated in the presence of T3 (10-4 M) also showed decreased vasoconstriction elicited by phenylephrine (1 µM) in intact-endothelium preparations. Moreover, T3 (10-4 M) vasorelaxation effect persisted in aortic rings preincubated with NG-nitro-L-arginine methylester (L-NAME, 10 µM), a nonspecific NO synthase (NOS) inhibitor. Finally, T3 (10-4 M) exhibited, in vitro, an antioxidant role by reducing NADPH oxidase activity and increasing SOD activity in the aorta's homogenates. CONCLUSION: T3 exerts dependent- and independent-endothelium vasodilation effects, which may be related to its role in maintaining redox homeostasis.

FUNDAMENTO: A disfunção vascular constitui a etiologia de diversas doenças, incluindo infarto do miocárdio e hipertensão, diante da ruptura da homeostase oxi-redutiva ("redox"), desempenhando um papel no desequilíbrio do mecanismo de controle vasomotor. Nosso grupo demonstrou anteriormente que os hormônios tireoidianos melhoram a sinalização da angiogênese, exercendo efeitos protetores sobre o tecido aórtico de ratos infartados. OBJETIVOS: Investigar o papel da triiodotironina (T3) na resposta vascular, explorando seus efeitos em aortas isoladas e a presença de mecanismos redox vasculares. MÉTODOS: Anéis aórticos isolados (endotélio intacto e desnudado) pré-contraídos com fenilefrina foram incubados com T3 (10-8, 10-7, 10-6, 10-5 e 10-4 M) e a tensão foi registrada usando um transdutor de deslocamento de força acoplado a um sistema de coleta. Para avaliar o envolvimento do estresse oxidativo, os anéis aórticos foram pré-incubados com T3 e posteriormente submetidos a um sistema de geração de espécies reativas de oxigênio (ROS) in vitro. O nível de significância adotado na análise estatística foi de 5%. RESULTADOS: A T3 (10-4 M) promoveu o vasorrelaxamento dos anéis aórticos pré-contraídos com fenilefrina em endotélio intacto e desnudado. Os anéis aórticos pré-incubados na presença de T3 (10-4 M) também mostraram diminuição da vasoconstrição provocada pela fenilefrina (1 µM) em preparações de endotélio intacto. Além disso, o efeito vasorrelaxante da T3 (10-4 M) persistiu em anéis aórticos pré-incubados com éster metílico de NG-nitro-L-arginina (L-NAME, 10 µM), um inibidor inespecífico da NO sintase (NOS). Por fim, a T3 (10-4 M) exibiu, in vitro, um papel antioxidante ao reduzir a atividade da NADPH oxidase e aumentar a atividade da SOD nos homogenatos aórticos. CONCLUSÃO: A T3 exerce efeitos dependentes e independentes de endotélio, o que pode estar relacionado ao seu papel na manutenção da homeostase redox.

Vascular contraction of umbilical arteries of pregnant women with preeclampsia.

Objective: Potassium channels have an important role in the vascular adaptation during pregnancy and a reduction in the expression of adenosine triphosphate-sensitive potassium channels (Katp) has been linked to preeclampsia. Activation of Katp induces vasodilation; however, no previous study has been conducted to evaluate the effects of the inhibition of these channels in the contractility of preeclamptic arteries. Glibenclamide is an oral antihyperglycemic agent that inhibits Katp and has been widely used in vascular studies. Methods: To investigate the effects of the inhibition of Katp, umbilical arteries of preeclamptic women and women with healthy pregnancies were assessed by vascular contractility experiments, in the presence or absence of glibenclamide. The umbilical arteries were challenged with cumulative concentrations of potassium chloride (KCl) and serotonin. Results: There were no differences between the groups concerning the maternal age and gestational age of the patients. The percentage of smokers, caucasians and primiparae per group was also similar. On the other hand, blood pressure parameters were elevated in the preeclamptic group. In addition, the preeclamptic group presented a significantly higher body mass index. The newborns of both groups presented similar APGAR scores and weights. Conclusion: In the presence of glibenclamide, there was an increase in the KCl-induced contractions only in vessels from the PE group, showing a possible involvement of these channels in the disorder.

The Enigma of Norbormide, a Rattus-Selective Toxicant.

Norbormide (NRB) is a Rattus-selective toxicant, which was serendipitously discovered in 1964 and formerly marketed as an eco-friendly rodenticide that was deemed harmless to non-Rattus species. However, due to inconsistent efficacy and the emergence of second-generation anticoagulants, its usage declined, with registration lapsing in 2003. NRBs' lethal action in rats entails irreversible vasoconstriction of peripheral arteries, likely inducing cardiac damage: however, the precise chain of events leading to fatality and the target organs involved remain elusive. This unique contractile effect is exclusive to rat arteries and is induced solely by the endo isomers of NRB, hinting at a specific receptor involvement. Understanding NRB's mechanism of action is crucial for developing species-selective toxicants as alternatives to the broad-spectrum ones currently in use. Recent research efforts have focused on elucidating its cellular mechanisms and sites of action using novel NRB derivatives. The key findings are as follows: NRB selectively opens the rat mitochondrial permeability transition pore, which may be a factor that contributes to its lethal effect; it inhibits rat vascular KATP channels, which potentially controls its Rattus-selective vasoconstricting activity; and it possesses intracellular binding sites in both sensitive and insensitive cells, as revealed by fluorescent derivatives. These studies have led to the development of a prodrug with enhanced pharmacokinetic and toxicological profiles, which is currently undergoing registration as a novel efficacious eco-sustainable Rattus-selective toxicant. The NRB-fluorescent derivatives also show promise as non-toxic probes for intracellular organelle labelling. This review documents in more detail these developments and their implications.

Adjuvant-induced arthritis promotes vascular hyporesponsiveness to phenylephrine through a nitric oxide-related mechanism.

Arthritis has important cardiovascular repercussions. Phenylephrine-induced vasoconstriction is impaired in rat aortas in the early phase of the adjuvant-induced arthritis (AIA), around the 15th day post-induction. Therefore, the present study aimed to verify the effects of AIA on hyporesponsiveness to phenylephrine in rat aortas. AIA was induced by intradermal injection of Mycobacterium tuberculosis (3.8 mg/dL) in the right hind paw of male Wistar rats (n=27). Functional experiments in isolated aortas were carried out 15 days after AIA induction. Morphometric and stereological analyses of the aortas were also performed 36 days after the induction of AIA. AIA did not promote structural modifications in the aortas at any of the time points studied. AIA reduced phenylephrine-induced contraction in endothelium-intact aortas, but not in endothelium-denuded aortas. However, AIA did not change KCl-induced contraction in either endothelium-intact or denuded aortas. L-NAME (non-selective NOS inhibitor), 1400W (selective iNOS inhibitor), and ODQ (guanylyl cyclase inhibitor) reversed AIA-induced hyporesponsiveness to phenylephrine in intact aortas. 7-NI (selective nNOS inhibitor) increased the contraction induced by phenylephrine in aortas from AIA rats. In summary, the hyporesponsiveness to phenylephrine induced by AIA was endothelium-dependent and mediated by iNOS-derived NO through activation of the NO-guanylyl cyclase pathway.

Angiotensin II Directly Increases Endothelial Calcium and Nitric Oxide in Kidney and Brain Microvessels In Vivo With Reduced Efficacy in Hypertension.

BACKGROUND: The vasoconstrictor effects of angiotensin II via type 1 angiotensin II receptors in vascular smooth muscle cells are well established, but the direct effects of angiotensin II on vascular endothelial cells (VECs) in vivo and the mechanisms how VECs may mitigate angiotensin II-mediated vasoconstriction are not fully understood. The present study aimed to explore the molecular mechanisms and pathophysiological relevance of the direct actions of angiotensin II on VECs in kidney and brain microvessels in vivo. METHODS AND RESULTS: Changes in VEC intracellular calcium ([Ca2+]i) and nitric oxide (NO) production were visualized by intravital multiphoton microscopy of cadherin 5-Salsa6f mice or the endothelial uptake of NO-sensitive dye 4-amino-5-methylamino-2',7'-difluorofluorescein diacetate, respectively. Kidney fibrosis by unilateral ureteral obstruction and Ready-to-use adeno-associated virus expressing Mouse Renin 1 gene (Ren1-AAV) hypertension were used as disease models. Acute systemic angiotensin II injections triggered >4-fold increases in VEC [Ca2+]i in brain and kidney resistance arterioles and capillaries that were blocked by pretreatment with the type 1 angiotensin II receptor inhibitor losartan, but not by the type 2 angiotensin II receptor inhibitor PD123319. VEC responded to acute angiotensin II by increased NO production as indicated by >1.5-fold increase in 4-amino-5-methylamino-2',7'-difluorofluorescein diacetate fluorescence intensity. In mice with kidney fibrosis or hypertension, the angiotensin II-induced VEC [Ca2+]i and NO responses were significantly reduced, which was associated with more robust vasoconstrictions, VEC shedding, and microthrombi formation. CONCLUSIONS: The present study directly visualized angiotensin II-induced increases in VEC [Ca2+]i and NO production that serve to counterbalance agonist-induced vasoconstriction and maintain residual organ blood flow. These direct and endothelium-specific angiotensin II effects were blunted in disease conditions and linked to endothelial dysfunction and the development of vascular pathologies.

Nitrergic inhibition of sympathetic arteriolar constrictions in the female rodent urethra.

During the urine storage phase, tonically contracting urethral musculature would have a higher energy consumption than bladder muscle that develops phasic contractions. However, ischaemic dysfunction is less prevalent in the urethra than in the bladder, suggesting that urethral vasculature has intrinsic properties ensuring an adequate blood supply. Diameter changes in rat or mouse urethral arterioles were measured using a video-tracking system. Intercellular Ca2+ dynamics in arteriolar smooth muscle (SMCs) and endothelial cells were visualised using NG2- and parvalbumin-GCaMP6 mice, respectively. Fluorescence immunohistochemistry was used to visualise the perivascular innervation. In rat urethral arterioles, sympathetic vasoconstrictions were predominantly suppressed by α,ß-methylene ATP (10 µM) but not prazosin (1 µM). Tadalafil (100 nM), a PDE5 inhibitor, diminished the vasoconstrictions in a manner reversed by N-ω-propyl-l-arginine hydrochloride (l-NPA, 1 µM), a neuronal NO synthesis (nNOS) inhibitor. Vesicular acetylcholine transporter immunoreactive perivascular nerve fibres co-expressing nNOS were intertwined with tyrosine hydroxylase immunoreactive sympathetic nerve fibres. In phenylephrine (1 µM) pre-constricted rat or mouse urethral arterioles, nerve-evoked vasodilatations or transient SMC Ca2+ reductions were largely diminished by l-nitroarginine (l-NA, 10 µM), a broad-spectrum NOS inhibitor, but not by l-NPA. The CGRP receptor antagonist BIBN-4096 (1 µM) shortened the vasodilatory responses, while atropine (1 µM) abolished the l-NA-resistant transient vasodilatory responses. Nerve-evoked endothelial Ca2+ transients were abolished by atropine plus guanethidine (10 µM), indicating its neurotransmitter origin and absence of non-adrenergic non-cholinergic endothelial NO release. In urethral arterioles, NO released from parasympathetic nerves counteracts sympathetic vasoconstrictions pre- and post-synaptically to restrict arteriolar contractility. KEY POINTS: Despite a higher energy consumption of the urethral musculature than the bladder detrusor muscle, ischaemic dysfunction of the urethra is less prevalent than that of the bladder. In the urethral arterioles, sympathetic vasoconstrictions are predominately mediated by ATP, not noradrenaline. NO released from parasympathetic nerves counteracts sympathetic vasoconstrictions by its pre-synaptic inhibition of sympathetic transmission as well as post-synaptic arteriolar smooth muscle relaxation. Acetylcholine released from parasympathetic nerves contributes to endothelium-dependent, transient vasodilatations, while CGRP released from sensory nerves prolongs NO-mediated vasodilatations. PDE5 inhibitors could be beneficial to maintain and/or improve urethral blood supply and in turn the volume and contractility of urethral musculature.

The Effect of an Elevated Dietary Copper Level on the Vascular Contractility and Oxidative Stress in Middle-Aged Rats.

Copper (Cu), being an essential mineral, plays a crucial role in maintaining physiological homeostasis across multiple bodily systems, notably the cardiovascular system. However, an increased Cu level in the body may cause blood vessel dysfunction and oxidative stress, which is unfavorable for the cardiovascular system. Middle-aged (7-8 months old) male Wistar rats (n/group = 12) received a diet supplemented with 6.45 mg Cu/kg (100% of the recommended daily dietary quantity of copper) for 8 weeks (Group A). The experimental group received 12.9 mg Cu/kg of diet (200%-Group B). An ex vivo study revealed that supplementation with 200% Cu decreased the contraction of isolated aortic rings to noradrenaline (0.7-fold) through FP receptor modulation. Vasodilation to sodium nitroprusside (1.10-fold) and acetylcholine (1.13-fold) was potentiated due to the increased net effect of prostacyclin derived from cyclooxygenase-1. Nitric oxide (NO, 2.08-fold), superoxide anion (O2•-, 1.5-fold), and hydrogen peroxide (H2O2, 2.33-fold) measured in the aortic rings increased. Blood serum antioxidant status (TAS, 1.6-fold), Cu (1.2-fold), Zn (1.1-fold), and the Cu/Zn ratio (1.4-fold) increased. An increase in Cu (1.12-fold) and the Cu/Zn ratio (1.09-fold) was also seen in the rats' livers. Meanwhile, cyclooxygenase-1 (0.7-fold), cyclooxygenase-2 (0.4-fold) and glyceraldehyde 3-phosphate dehydrogenase (0.5-fold) decreased. Moreover, a negative correlation between Cu and Zn was found (r = -0.80) in rat serum. Supplementation with 200% Cu did not modify the isolated heart functioning. No significant difference was found in the body weight, fat/lean body ratio, and organ weight for either the heart or liver, spleen, kidney, and brain. Neither Fe nor Se, the Cu/Se ratio, the Se/Zn ratio (in serum and liver), heme oxygenase-1 (HO-1), endothelial nitric oxide synthase (eNOS), or intercellular adhesion molecule-1 (iCAM-1) (in serum) were modified. Supplementation with 200% of Cu potentiated pro-oxidant status and modified vascular contractility in middle-aged rats.

Resolvin D2 prevents vascular remodeling, hypercontractility and endothelial dysfunction in obese hypertensive mice through modulation of vascular and proinflammatory factors.

During resolution of inflammation, specialized proresolving mediators (SPMs), including resolvins, are produced to restore tissue homeostasis. We hypothesized that there might be a dysregulation of SPMs pathways in pathological vascular remodeling and that resolvin D2 (RvD2) might prevent vascular remodeling and contractile and endothelial dysfunction in a model of obesity and hypertension. In aortic samples of patients with or without abdominal aortic aneurysms (AAA), we evaluated gene expression of enzymes involved in SPMs synthesis (ALOXs), SPMs receptors and pro-inflammatory genes. In an experimental model of aortic dilation induced by high fat diet (HFD, 60%, eighteen weeks) and angiotensin II (AngII) infusion (four weeks), we studied the effect of RvD2 administration in aorta and small mesenteric arteries structure and function and markers of inflammation. In human macrophages we evaluated the effects of AngII and RvD2 in macrophages function and SPMs profile. In patients, we found positive correlations between AAA and obesity, and between AAA and expression of ALOX15, RvD2 receptor GPR18, and pro-inflammatory genes. There was an inverse correlation between the expression of aortic ALOX15 and AAA growth rate. In the mice model, RvD2 partially prevented the HFD plus AngII-induced obesity and adipose tissue inflammation, hypertension, aortic and mesenteric arteries remodeling, hypercontratility and endothelial dysfunction, and the expression of vascular proinflammatory markers and cell apoptosis. In human macrophages, RvD2 prevented AngII-induced impaired efferocytosis and switched SPMs profile. RvD2 might represent a novel protective strategy in preventing vascular damage associated to hypertension and obesity likely through effects in vascular and immune cells.

Resveratrol attenuates cyclosporin A-induced upregulation of the thromboxane A2 receptor and hypertension via the AMPK/SIRT1 and MAPK/NF-κB pathways in the rat mesenteric artery.

Cyclosporin A, an immunosuppressive agent, is extensively utilized for the prevention of transplant rejection and treat autoimmune disease in the clinic, despite its association with a high risk of hypertension development among patients. Resveratrol is a kind of non-flavonoid phenolic compound that widely exists in many plants. The aim of the present study was to investigate the mechanism by which resveratrol ameliorates cyclosporin A-induced hypertension. The arterial rings of the mesentery were incubated with cyclosporin A and resveratrol in vitro. Rats were administered cyclosporin A and/or resveratrol for 3 weeks in vivo. Blood pressure was measured via the tail arteries. Vasoconstriction curves were recorded using a sensitive myograph. The protein expression was evaluated through Western blotting. This study demonstrated that resveratrol mitigated the cyclosporin A-induced increase in blood pressure in rats. Furthermore, resveratrol markedly inhibited the cyclosporin A-induced upregulation of thromboxane A2 receptor-mediated vasoconstriction in the rat mesenteric artery both in vitro and in vivo. Moreover, resveratrol activated AMPK/SIRT1 and inhibited the MAPK/NF-κB signaling pathway. In conclusion, resveratrol restored the cyclosporin A-induced upregulation of the thromboxane A2 receptor and hypertension via the AMPK/SIRT1 and MAPK/NF-κB pathways in rats.

Nardilysin in vascular smooth muscle cells controls blood pressure via the regulation of calcium dynamics.

Blood pressure is a crucial physiological parameter and its abnormalities can cause a variety of health problems. We have previously reported that mice with systemic deletion of nardilysin (NRDC), an M16 family metalloprotease, exhibit hypotension. In this study, we aimed to clarify the role of NRDC in vascular smooth muscle cell (VSMC) by generating VSMC-specific Nrdc knockout (VSMC-KO) mice. Our findings reveal that VSMC-KO mice also exhibit hypotension. Aortas isolated from VSMC-KO mice exhibited a weakened contractile response to phenylephrine, accompanied by reduced phosphorylation of myosin light chain 2 and decreased rhoA expression. VSMC isolated from VSMC-KO aortas showed a reduced increase in intracellular Ca2+ concentration induced by α-stimulants. These findings suggest that NRDC in VSMC regulates vascular contraction and blood pressure by modulating Ca2+ dynamics.

Relation of Vasoreactivity in the Left and Right Coronary Arteries During Acetylcholine Spasm Provocation Testing.

The diagnosis of vasospastic angina (VSA) according to Japanese guidelines involves an initial intracoronary acetylcholine (ACh) provocation test in the left coronary artery (LCA) followed by testing in the right coronary artery (RCA). However, global variations in test protocols often lead to the omission of ACh provocation in the RCA, potentially resulting in the underdiagnosis of VSA. This study assessed the validity of the LCA-only ACh provocation approach for the VSA diagnosis and whether vasoreactivity in the LCA aids in determining further provocation in the RCA. A total of 273 patients who underwent sequential intracoronary ACh provocation testing in the LCA and RCA were included. Patients with a positive ACh provocation test in the LCA were excluded. Relations between vasoreactivity in the LCA and ACh test outcomes (positivity and adverse events) in the RCA were evaluated. In patients with negative ACh test results in the LCA, subsequent ACh testing was positive in the RCA in 23 of 273 (8.4%) patients. In patients with minimal LCA vasoconstriction (<25%), only 3.0% had a positive ACh test in the RCA, whereas the ACh test in the RCA was positive in 13.5% of those with LCA constriction of 25% to 90% (p = 0.002). No major adverse events occurred during ACh testing in the RCA. In conclusion, for the VSA diagnosis, the omission of ACh provocation in the RCA may be clinically acceptable, particularly when vasoconstriction induced by ACh injection was minimal in the LCA. Further studies are needed to define ACh provocation protocols worldwide.

Active Anchoring Stimuli-Responsive Nano-Craft to Relieve Pulmonary Vasoconstriction by Targeting Smooth Muscle Cell for Hypoxic Pulmonary Hypertension Treatment.

Recently, nanotechnology-based drug delivery platforms in treating pulmonary arterial hypertension (PAH) have gradually emerged. However, large mechanical stress and shear stress in blood vessels greatly affect the retention of nanopreparative materials at lesion sites, severely limiting nanotechnology-based drug delivery. Herein, a stimuli-responsive nanocraft is rationally designed by actively anchoring E-selectin overexpressed on pulmonary arterial endothelial cells (PAECs), under hypoxic conditions, allowing effective accumulation and retention of the drug at the lesion site. Briefly, a nitrobenzene group is incorporated into the framework of a nanocarrier, and then it is simultaneously linked with chitosan. Additionally, the surface of the nanocarrier with sialic acid (SA) and encapsulated the clinically used drug ambrisentan (Am), which enables the anchoring of E-selectin and subsequent drug delivery is modifed. This system facilitates intercellular transport to pulmonary artery smooth muscle cells (PASMCs) when targeting PAECs and specifically responds to a reductive hypoxic microenvironment with elevated nitroreductase in PASMCs. Moreover, compared with free Am, nanoencapsulation and SA-PEG2000-NH2 prolong the blood circulation time, achieving better therapeutic outcomes in preventing vascular remodeling and reversing systolic dysfunction. The originality and contribution of this work reveal the promising value of this pulmonary arterial anchoring stimuli-responsive nanocraft as a novel therapeutic strategy for satisfactory PAH treatment.

Endothelial cell Orai1 is essential for endothelium-dependent contraction of mouse carotid arteries in normotensive and hypertensive mice.

Endothelium-dependent contraction (EDC) exists in blood vessels of normotensive animals, but is exaggerated in hypertension. An early signal in EDC is cytosolic Ca2+ rise in endothelial cells. In this study we investigated the functional role of Orai1, a major endothelial cell Ca2+ entry channel, in EDC. Hypertension model was established in WT mice by intake of L-NNA in the drinking water (0.5 g/L) for 4 weeks or osmotic pump delivery of Ang II (1.5 mg·kg-1·d-1) for 2 weeks. In TRPC5 KO mice, the concentration of L-NNA and Ang II were increased to 1 g/L or 2 mg·kg-1·d-1, respectively. Arterial segments were prepared from carotid arteries and aortas, and EDC was elicited by acetylcholine in the presence of Nω-nitro-L-arginine methyl ester. We showed that low concentration of acetylcholine (3-30 nM) initiated relaxation in phenylephrine-precontracted carotid arteries of both normotensive and hypertensive mice, while high concentration of acetylcholine (0.1-2 µM) induced contraction. Application of selective Orai1 inhibitors AnCoA4 (100 µM) or YM58483 (400 nM) had no effect on ACh-induced relaxation but markedly reduced acetylcholine-induced EDC. We found that EDC was increased in hypertensive mice compared with that of normotensive mice, which was associated with increased Orai1 expression in endothelial cells of hypertensive mice. Compared to TRPC5 and TRPV4, which were also involved in EDC, endothelial cell Orai1 had relatively greater contribution to EDC than either TRPC5 or TRPV4 alone. We identified COX-2, followed by PGF2α, PGD2 and PGE2 as the downstream signals of Orai1/TRPC5/TRPV4. In conclusion, Orai1 coordinates together with TRPC5 and TRPV4 in endothelial cells to regulate EDC responses. This study demonstrates a novel function of Orai1 in EDC in both normotensive and hypertensive mice, thus providing a general scheme about the control of EDC by Ca2+-permeable channels.

Avaliação do colírio de brimonidina 0, 2% em comparação à nafazolina 0,025% + feniramina 0,3% nas cirurgias de estrabismo / Evaluation of 0.2% brimonidine eye drops compared to 0.025% naphazoline + 0.3% pheniramine in strabismus surgery

RESUMO Objetivo: Avaliar o efeito do colírio de brimonidina 0,2% na redução da hiperemia e do sangramento ocular durante as cirurgias de estrabismo, em comparação com o colírio de nafazolina 0,025% + feniramina 0,3%. Métodos: Foram avaliados 14 pacientes com estrabismo e indicação de correção cirúrgica bilateral. Foi instilado antes do procedimento, de forma aleatória, um colírio em cada olho dos pacientes avaliados. A análise subjetiva da hiperemia conjuntival e do sangramento perioperatório foi realizada de forma duplo-cega, por dois cirurgiões. A avaliação objetiva do nível de hiperemia conjuntival foi realizada por análise das imagens obtidas por meio do software ImageJ®. Resultados: A análise de modelos multivariados de efeito misto indicou diferenças estatisticamente significantes entre os grupos em relação à hiperemia (avaliador 2) e ao sangramento intraoperatório (avaliadores 1 e 2), com maiores escores nos casos tratados com colírio de nafazolina + feniramina. Entretanto, não houve diferença estatística na análise objetiva realizada por meio da saturação de cores obtidas pelo programa ImageJ®. Conclusão: O colírio de brimonidina pode ser superior ao colírio de nafazolina + feniramina na redução do sangramento, levando-se em conta apenas a análise subjetiva.

ABSTRACT Objective: To evaluate the effect of 0.2% brimonidine eye drops in reducing hyperemia and ocular bleeding during strabismus surgeries, in comparison with 0.025% naphazoline + 0.3% pheniramine eye drops. Methods: Fourteen patients with strabismus and indication for bilateral surgical correction were evaluated. Before the procedure, the eye drops were instilled randomly in each eye of the evaluated patients. The subjective analysis of conjunctival hyperemia and perioperative bleeding was performed in a double-blind manner, by 02 surgeons. The objective assessment of the level of conjunctival hyperemia was performed by analyzing the images obtained using the ImageJ® software. Results: The analysis of multivariate mixed effect models indicated statistically significant differences between the groups in relation to hyperemia (rater 2) and intraoperative bleeding (raters 1 and 2) with higher scores in cases treated with naphazoline + pheniramine eye drops. However, there were no statistically significant differences in the objective analysis of color saturation obtained by the ImageJ® program. Conclusion: Brimonidine eye drops may be superior to naphazoline + pheniramine eye drops in reducing bleeding, taking into account the subjective analysis only.