Sympathy for the devil: the role of thromboxane in the regulation of vascular tone and blood pressure

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.

Increased Coronary Contraction to Thromboxane A2 in Cardiac Surgery Patients With Poorly Controlled Hypertension

INTRODUCTION

Cardioplegia and cardiopulmonary bypass (CP/CPB) alters coronary arteriolar response to thromboxane A2 (TXA2) in patients undergoing cardiac surgery. Comorbidities, including hypertension (HTN), can further alter coronary vasomotor tone. This study investigates the effects of HTN on coronary arteriolar response to TXA2 pre and post-CP/CPB and cardiac surgery.

MATERIALS AND METHODS

Coronary arterioles pre and post-CP/CPB were dissected from atrial tissue samples in patients with no HTN (NH, n = 9), well-controlled HTN (WC, n = 12), or uncontrolled HTN (UC, n = 12). In-vitro coronary microvascular reactivity was examined in the presence of TXA2 analog U46619 (10-9-10-4M). Protein expression of TXA2 receptor in the harvested right atrial tissue samples were measured by immunoblotting.

RESULTS

TXA2 analog U46619 induced dose-dependent contractile responses of coronary arterioles in all groups. Pre-CPB contractile responses to U46619 were significantly increased in microvessels in the UC group compared to the NH group (P < 0.05). The pre-CP/CPB contractile responses of coronary arterioles were significantly diminished post-CP/CPB among the three groups (P < 0.05), but there remained an increased contractile response in the microvessels of the UC group compared to the WC and NH groups (P < 0.05). There were no significant differences in U46619-induced vasomotor tone between patients in the NH and WC groups (P > 0.05). There were no differences in expression of TXA2R among groups.

CONCLUSIONS

Poorly controlled HTN is associated with increased contractile response of coronary arterioles to TXA2. This alteration may contribute to worsened recovery of coronary microvascular function in patients with poorly controlled HTN after CP/CPB and cardiac surgery.

Vasoplegic Syndrome and Anaesthesia: A Narrative Review

Vasoplegic syndrome (VS) is defined as low systemic vascular resistance, normal or high cardiac output, and resistant hypotension unresponsive to vasopressor agents and intravenous volume. VS is a frequently encountered complication in cardiovascular and transplantation surgery, burns, trauma, pancreatitis, and sepsis. The basis of the pathophysiology is associated with an imbalance of vasodilator and vasoconstrictive structure in vascular smooth muscle cells and is highly complex. The pathogenesis of VS has several mechanisms, including overproduction of iNO, stimulation of ATP-dependent K+ channels and NF-κB, and vasopressin receptor 1A (V1A-receptor) down-regulation. Available treatments involve volume and inotropes administration, vasopressin, methylene blue, hydroxocobalamin, Ca++, vitamin C, and thiamine, and should also restore vascular tone and improve vasoplegia. Other treatments could include angiotensin II, corticosteroids, NF-κB inhibitor, ATP-dependent K+ channel blocker, indigo carmine, and hyperbaric oxygen therapy. Despite modern advances in treatment, the mortality rate is still 30-50%. It is challenging for an anaesthesiologist to consider this syndrome's diagnosis and manage its treatment. Our review aims to review the diagnosis, predisposing factors, pathophysiology, treatment, and anaesthesia approach of VS during anaesthesia and to suggest a treatment algorithm.

Anti-Cancer Prodrug Cyclophosphamide Exerts Thrombogenic Effects on Human Venous Endothelial Cells Independent of CYP450 Activation-Relevance to Thrombosis

Cancer patients are at a very high risk of serious thrombotic events, often fatal. The causes discussed include the detachment of thrombogenic particles from tumor cells or the adverse effects of chemotherapeutic agents. Cytostatic agents can either act directly on their targets or, in the case of a prodrug approach, require metabolization for their action. Cyclophosphamide (CPA) is a widely used cytostatic drug that requires prodrug activation by cytochrome P450 enzymes (CYP) in the liver. We hypothesize that CPA could induce thrombosis in one of the following ways: (1) damage to endothelial cells (EC) after intra-endothelial metabolization; or (2) direct damage to EC without prior metabolization. In order to investigate this hypothesis, endothelial cells (HUVEC) were treated with CPA in clinically relevant concentrations for up to 8 days. HUVECs were chosen as a model representing the first place of action after intravenous CPA administration. No expression of CYP2B6, CYP3A4, CYP2C9 and CYP2C19 was found in HUVEC, but a weak expression of CYP2C18 was observed. CPA treatment of HUVEC induced DNA damage and a reduced formation of an EC monolayer and caused an increased release of prostacyclin (PGI2) and thromboxane (TXA) associated with a shift of the PGI2/TXA balance to a prothrombotic state. In an in vivo scenario, such processes would promote the risk of thrombus formation.

Nanomaterial Inhalation During Pregnancy Alters Systemic Vascular Function in a Cyclooxygenase-Dependent Manner

Pregnancy requires rapid adaptations in the uterine microcirculation to support fetal development. Nanomaterial inhalation is associated with cardiovascular dysfunction, which may impair gestation. We have shown that maternal nano-titanium dioxide (nano-TiO2) inhalation impairs microvascular endothelial function in response to arachidonic acid and thromboxane (TXA2) mimetics. However, the mechanisms underpinning this process are unknown. Therefore, we hypothesize that maternal nano-TiO2 inhalation during gestation results in uterine microvascular prostacyclin (PGI2) and TXA2 dysfunction. Pregnant Sprague-Dawley rats were exposed from gestational day 10-19 to nano-TiO2 aerosols (12.17  ± 1.67 mg/m3) or filtered air (sham-control). Dams were euthanized on gestational day 20, and serum, uterine radial arterioles, implantation sites, and lungs were collected. Serum was assessed for PGI2 and TXA2 metabolites. TXB2, the stable TXA2 metabolite, was significantly decreased in nano-TiO2 exposed dams (597.3 ± 84.4 vs 667.6 ± 45.6 pg/ml), whereas no difference was observed for 6-keto-PGF1α, the stable PGI2 metabolite. Radial arteriole pressure myography revealed that nano-TiO2 exposure caused increased vasoconstriction to the TXA2 mimetic, U46619, compared with sham-controls (-41.3% ± 4.3% vs -16.8% ± 3.4%). Nano-TiO2 exposure diminished endothelium-dependent vasodilation to carbaprostacyclin, a PGI2 receptor agonist, compared with sham-controls (30.0% ± 9.0% vs 53.7% ± 6.0%). Maternal nano-TiO2 inhalation during gestation decreased nano-TiO2 female pup weight when compared with sham-control males (3.633 ± 0.064 vs 3.995 ± 0.124 g). Augmented TXA2 vasoconstriction and decreased PGI2 vasodilation may lead to decreased placental blood flow and compromise maternofetal exchange of waste and nutrients, which could ultimately impact fetal health outcomes.

Endothelial Cells and the Cerebral Circulation

Endothelial cells form the innermost layer of all blood vessels and are the only vascular component that remains throughout all vascular segments. The cerebral vasculature has several unique properties not found in the peripheral circulation; this requires that the cerebral endothelium be considered as a unique entity. Cerebral endothelial cells perform several functions vital for brain health. The cerebral vasculature is responsible for protecting the brain from external threats carried in the blood. The endothelial cells are central to this requirement as they form the basis of the blood-brain barrier. The endothelium also regulates fibrinolysis, thrombosis, platelet activation, vascular permeability, metabolism, catabolism, inflammation, and white cell trafficking. Endothelial cells regulate the changes in vascular structure caused by angiogenesis and artery remodeling. Further, the endothelium contributes to vascular tone, allowing proper perfusion of the brain which has high energy demands and no energy stores. In this article, we discuss the basic anatomy and physiology of the cerebral endothelium. Where appropriate, we discuss the detrimental effects of high blood pressure on the cerebral endothelium and the contribution of cerebrovascular disease endothelial dysfunction and dementia. © 2022 American Physiological Society. Compr Physiol 12:3449-3508, 2022.

Implications of Endothelial Cell-Mediated Dysfunctions in Vasomotor Tone Regulation

Cardiovascular diseases (CVD) constitute the major cause of death worldwide and show a higher prevalence in the adult population. The human umbilical cord consistsof two arteries and one vein, both composed of three tunics. The tunica intima, lined with endothelial cells, regulates vascular tone through the production/release of vasoregulatory substances. These substances can be vasoactive factors released by endothelial cells (ECs) that cause vasodilation (NO, PGI2, EDHF, and Bradykinin) or vasoconstriction (ET1, TXA2, and Ang II) depending on the cell type (ECs or SMC) that reacts to the stimulus. Vascular studies using ECs are important for the analysis of cardiovascular diseases since endothelial dysfunction is an important CVD risk factor. In this paper, we will address the morphological characteristics of the human umbilical cord and its component vessels. the constitution of the vascular endothelium, and the evolution of human umbilical cord-derived endothelial cells when isolated. Moreover, the role played by the endothelium in the vasomotor tone regulation, and how it may be associated with the existence of CVD, were discussed.

Effects of Curcumin on Depression and Anxiety: A Narrative Review of the Recent Clinical Data

Depressive and anxiety disorders affect a significant proportion of the global population and constitute one of the highest disease burdens worldwide. Conventional pharmacological treatments are traditionally the first line of therapy for individuals affected by these conditions although these are only successful approximately half of the time and are often associated with undesirable side effects. This review describes the use of the natural substance curcumin as a potential alternative treatment of these mental disorders. With this in mind, we analyzed the effects of curcumin in eight clinical studies of depression and five studies of anxiety and assessed these using psychiatric symptom scores and molecular biomarker readouts.

Intravital Imaging Identifies the VEGF-TXA2 Axis as a Critical Promoter of PGE2 Secretion from Tumor Cells and Immune Evasion

Prostaglandin E₂ (PGE₂) promotes tumor progression through evasion of antitumor immunity. In stark contrast to cyclooxygenase-dependent production of PGE₂, little is known whether PGE₂ secretion is regulated within tumor tissues. Here, we show that VEGF-dependent release of thromboxane A₂ (TXA₂) triggers Ca²⁺ transients in tumor cells, culminating in PGE₂ secretion and subsequent immune evasion in the early stages of tumorigenesis. Ca²⁺ transients caused cPLA2 activation and triggered the arachidonic acid cascade. Ca²⁺ transients were monitored as the surrogate marker of PGE₂ secretion. Intravital imaging of Braf^V600E mouse melanoma cells revealed that the proportion of cells exhibiting Ca²⁺ transients is markedly higher in vivo than in vitro. The TXA₂ receptor was indispensable for the Ca²⁺ transients in vivo, high intratumoral PGE₂ concentration, and evasion of antitumor immunity. Notably, treatment with a VEGF receptor antagonist and an anti-VEGF antibody rapidly suppressed Ca²⁺ transients and reduced TXA₂ and PGE₂ concentrations in tumor tissues. These results identify the VEGF-TXA₂ axis as a critical promoter of PGE₂-dependent tumor immune evasion, providing a molecular basis underlying the immunomodulatory effect of anti-VEGF therapies. SIGNIFICANCE: This study identifies the VEGF-TXA₂ axis as a potentially targetable regulator of PGE₂ secretion, which provides novel strategies for prevention and treatment of multiple types of malignancies.

Pemafibrate, A Novel Selective Peroxisome Proliferator-Activated Receptor α Modulator, Reduces Plasma Eicosanoid Levels and Ameliorates Endothelial Dysfunction in Diabetic Mice

Aims: Various pathological processes related to diabetes cause endothelial dysfunction. Eicosanoids derived from arachidonic acid (AA) have roles in vascular regulation. Fibrates have recently been shown to attenuate vascular complications in diabetics. Here we examined the effects of pemafibrate, a selective peroxisome proliferator-activated receptor α modulator, on plasma eicosanoid levels and endothelial function in diabetic mice.

Methods: Diabetes was induced in 7-week-old male wild-type mice by a single injection of streptozotocin (150 mg/kg). Pemafibrate (0.3 mg/kg/day) was administered orally for 3 weeks. Untreated mice received vehicle. Circulating levels of eicosanoids and free fatty acids were measured using both gas and liquid chromatography-mass spectrometry. Endothelium-dependent and endothelium-independent vascular responses to acetylcholine and sodium nitroprusside, respectively, were analyzed.

Results: Pemafibrate reduced both triglyceride and non-high-density lipoprotein-cholesterol levels ( P ＜0.01), without affecting body weight. It also decreased circulating levels of AA ( P ＜0.001), thromboxane B ₂ ( P ＜0.001), prostaglandin E ₂ , leukotriene B ₄ ( P ＜0.05), and 5-hydroxyeicosatetraenoic acid ( P ＜0.001), all of which were elevated by the induction of diabetes. In contrast, the plasma levels of 15-deoxy-Δ ^12,14 -prostaglandin J ₂ , which declined following diabetes induction, remained unaffected by pemafibrate treatment. In diabetic mice, pemafibrate decreased palmitic acid (PA) and stearic acid concentrations ( P ＜0.05). Diabetes induction impaired endothelial function, whereas pemafibrate ameliorated it ( P ＜0.001). The results of ex vivo experiments indicated that eicosanoids or PA impaired endothelial function.

Conclusion: Pemafibrate diminished the levels of vasoconstrictive eicosanoids and free fatty acids accompanied by a reduction of triglyceride. These effects may be associated with the improvement of endothelial function by pemafibrate in diabetic mice.

Hemoadsorption during Cardiopulmonary Bypass in Patients with Endocarditis Undergoing Valve Surgery: A Retrospective Single-Center Study

Background: Aim of this study was to evaluate the outcomes of endocarditis patients undergoing valve surgery with the Cytosorb^® hemoadsorption (HA) device during cardiopulmonary bypass. Methods: From 2009 until 2019, 241 patients had undergone valve surgery due to endocarditis at the Department of Cardiac Surgery, University Hospital of Basel. We compared patients who received HA during surgery (n = 41) versus patients without HA (n = 200), after applying inverse probability of treatment weighting. Results: In-hospital mortality, major adverse cardiac and cerebrovascular events and postoperative renal failure were similar in both groups. Demand for norepinephrine (88.4 vs. 52.8%; p = 0.001), milrinone (42.2 vs. 17.2%; p = 0.046), red blood cell concentrates (65.2 vs. 30.6%; p = 0.003), and platelets (HA vs. Control: 36.7 vs. 9.8%; p = 0.013) were higher in the HA group. In addition, a higher incidence of reoperation for bleeding (34.0 vs. 7.7 %; p = 0.011), and a prolonged length of in-hospital stay (15.2 (11.8 to 19.6) vs. 9.0 (7.1 to 11.3) days; p = 0.017) were observed in the HA group. Conclusions: No benefits of HA-therapy were observed in patients with infective endocarditis undergoing valve surgery.

Extracellular Vesicles and Preeclampsia: Current Knowledge and Future Research Directions

Preeclampsia (PE) is associated with long-term morbidity in mothers and lifelong morbidities for their children, ranging from cerebral palsy and cognitive delay in preterm infants, to hypertension, diabetes and obesity in adolescents and young adults. There are several processes that are critical for development of materno-fetal exchange, including establishing adequate perfusion of the placenta by maternal blood, and the formation of the placental villous vascular tree. Recent studies provide persuasive evidence that placenta-derived extracellular vesicles (EVs) represent a significant intercellular communication pathway, and that they may play an important role in placental and endothelial cell (both fetal and maternal) function. These functions are known to be altered in PE. EVs can carry and transport a wide range of bioactive molescules that have potential to be used as biomarkers and therapeutic delivery tools for PE. EV content is often parent cell specific, thus providing an insight or "thumbprint" of the intracellular environment of the originating cell (e.g., human placenta). EV have been identified in plasma under both normal and pathological conditions, including PE. The concentration of EVs and their content in plasma has been reported to increase in association with disease severity and/or progression. Placenta-derived EVs have been identified in maternal plasma during normal pregnancy and PE pregnancies. They contain placenta-specific proteins and miRNAs and, as such, may be differentiated from maternally-derived EVs. The aim of this review, thus, is to describe the potential roles of EVs in preecmpatic pregnancies, focussing on EVs secreted from placental cells. The biogenesis, specificity of placental EVs, and methods used to characterise EVs in the context of PE pregnancies will be also discussed.

Empagliflozin ameliorates endothelial dysfunction and suppresses atherogenesis in diabetic apolipoprotein E-deficient mice

Recent studies reported cardioprotective effects of sodium glucose co-transporter 2 (SGLT2) inhibitors; however, the underlying mechanisms are still obscure. Here, we investigated whether empagliflozin attenuates atherogenesis and endothelial dysfunction in diabetic apolipoprotein E-deficient (ApoE^-/-) mice. Male streptozotocin (STZ) - induced diabetic ApoE^-/- mice were treated with empagliflozin for 12 or 8 weeks. Empagliflozin lowered blood glucose (P < 0.001) and lipid levels in diabetic ApoE^-/- mice. Empagliflozin treatment for 12 weeks significantly decreased atherosclerotic lesion size in the aortic arch (P < 0.01) along with reduction of lipid deposition (P < 0.05), macrophage accumulation (P < 0.001), and inflammatory molecule expression in plaques compared with the untreated group. Empagliflozin treatment for 8 weeks significantly ameliorated diabetes-induced endothelial dysfunction as determined by the vascular response to acetylcholine (P < 0.001). Empagliflozin reduced RNA expression of a macrophage marker, CD68, and inflammatory molecules such as MCP-1 (P < 0.05) and NADPH oxidase subunits in the aorta compared with the untreated group. Empagliflozin also reduced plasma levels of vasoconstrictive eicosanoids, prostaglandin E₂ and thromboxane B₂ (P < 0.001), which were elevated in diabetic condition. Furthermore, empagliflozin attenuated RNA expression of inflammatory molecules in perivascular adipose tissue (PVAT), suggesting the reduction of inflammation in PVAT. In in vitro studies, methylglyoxal (MGO), a precursor of AGEs, significantly increased the expression of inflammatory molecules such as MCP-1 and TNF-α in a murine macrophage cell line, RAW264.7. Our results indicated that empagliflozin attenuated endothelial dysfunction and atherogenesis in diabetic ApoE^-/- mice. Reduction of vasoconstrictive eicosanoids and inflammation in the vasculature and PVAT may have a role as underlying mechanisms at least partially.

Gonadal function protects against organ culture-induced vascular damage. Involvement of prostanoids

Androgen deprivation induces vascular dysfunction in which altered release and action of prostanoids has been extensively studied. On the other hand, the vascular organ-culture system has been reported as a valid model for phenotypic changes that occur in several cardiovascular pathologies. Since there are no studies analyzing the impact of androgenic loss on vascular vulnerability during induced vascular damage, the objective of this study was to analyze the possible preventive role of male sex hormones on the organ culture-induced vascular damage in rat aorta. The link to possible changes in gross structure was also analyzed. For this purpose, fresh and 20 h-cultured aortic arterial segments from intact and orchidectomized rats were used to analyze: (i) the release and vasomotor effect of the thromboxane A₂ (TXA₂), prostaglandin (PG) E₂, PGF_2α and PGI₂; (ii) the vasodilator response induced by acetylcholine (ACh) as well as the involvement of prostanoids, in particular TXA₂, in the ACh-induced response; (iii) the effect of activation of thromboxane/prostaglandin (TP) receptors on the ACh-induced response; and (iv) the vascular structure. The results showed that organ culture: i) increased production of prostanoids; ii) increased prostanoids-induced vasomotor responses; iii) decreased ACh-induced relaxation after incubation with indomethacin, a blocker of cyclooxygenases; iv) increased the ACh-induced relaxation after incubation with the TXA₂ synthase inhibitor, furegrelate, more in arteries from orchidectomized rats than in those of intact rats; v) diminished ACh-induced relaxation after U-46619 incubation only in arteries from orchidectomized rats; and vi) preserved the integrity of the different vascular layers. These results showed the protective role of male sex hormones against the induced vascular damage, since a decreased deleterious effect of prostanoids, in particular that of TXA₂, was observed in arteries from rats with intact gonadal function.

Pyruvate Protects Against Intestinal Injury by Inhibiting the JAK/STAT Signaling Pathway in Rats With Hemorrhagic Shock

BACKGROUND

This study aimed to investigate the role of Janus kinase/signal transducers and activators of transcription (JAK/STAT) signaling pathway in protection by peritoneal resuscitation (PR) using pyruvate-peritoneal dialysis solution (PY-PDS) against intestinal injury from hemorrhagic shock (HS) in rats.

MATERIALS AND METHODS

Sixty-four rats were assigned to eight groups: group SHAM; group intravenous resuscitation (VR); groups NS, LA, and PY in which the rats were subjected to HS and PR with normal saline (NS), lactate-peritoneal dialysis solution (LA-PDS), and PY-PDS, respectively, combined with VR; and groups DMSO, RPM, and AG490 in which the rats were subjected to HS and VR with pretreatment of dimethyl sulfoxide (DMSO), rapamycin (RPM), and tyrphostin B42 (AG490).

RESULTS

At 2 h after HS and resuscitation, the levels of diamine oxidase, 15-F_2t-isoprostane, thromboxane B₂, and endothelin-1, in the blood and the intestinal mucosal apoptotic index and caspase-3 were lower in groups PY, RPM, and AG490 than in groups VR, NS, LA, and DMSO. Group PY showed lower levels of malondialdehyde and myeloperoxidase and a higher level of superoxide dismutase than groups VR, NS, and LA. Phosphorylated JAK2 and phosphorylated STAT3 levels were lower in groups PY, RPM, AG490, and LA than in groups VR, NS, and DMSO.

CONCLUSIONS

The protection mechanism of PR with PY-PDS combined with VR was related to the inhibition of the JAK/STAT signaling pathway during HS and resuscitation. The process might include suppression of oxidative stress, reduction of neutrophil infiltration, regulation of microcirculation, and inhibition of apoptosis.

Altered cyclooxygenase-1 and enhanced thromboxane receptor activities underlie attenuated endothelial dilatory capacity of omental arteries in obesity

AIMS

Obesity is a risk factor for endothelial dysfunction, the severity of which is likely to vary depending on extent and impact of adiposity on the vasculature. This study investigates the roles of cyclooxygenase isoforms and thromboxane receptor activities in the differential endothelial dilatory capacities of arteries derived from omental and subcutaneous adipose tissues in obesity.

MAIN METHODS

Small arteries were isolated from omental and subcutaneous adipose tissues obtained from consented morbidly obese patients (n = 65, BMI 45 ± 6 kg m^-2 [Mean ± SD]) undergoing bariatric surgery. Relaxation to acetylcholine was studied by wire myography in the absence or presence of indomethacin (10 μM, cyclooxygenase inhibitor), FR122047 (1 μM, cyclooxygenase-1 inhibitor), Celecoxib (4 μM, cyclooxygenase-2 inhibitor), Nω-Nitro-L-arginine methyl ester (L-NAME, 100 μM, nitric oxide synthase inhibitor) or combination of apamin (0.5 μM) and charybdotoxin (0.1 μM) that together inhibit endothelium-derived hyperpolarizing factor (EDHF). Contractions to U46619 (thromboxane A₂ mimetic) were also studied.

KEY FINDINGS

Acetylcholine relaxation was significantly attenuated in omental compared with subcutaneous arteries from same patients (p < 0.01). Indomethacin (p < 0.01) and FR122047 (p < 0.001) but not Celecoxib significantly improved the omental arteriolar relaxation. Cyclooxygenase-1 mRNA and U46619 contractions were both increased in omental compared with subcutaneous arteries (p < 0.05). L-NAME comparably inhibited acetylcholine relaxation in both arteries, while apamin+charybdotoxin were less effective in omental compared with subcutaneous arteries.

SIGNIFICANCE

The results show that the depot-specific reduction in endothelial dilatory capacity of omental compared with subcutaneous arteries in obesity is in large part due to altered cyclooxygenase-1 and enhanced thromboxane receptor activities, which cause EDHF deficiency.

Molecular Targets of Aspirin and Prevention of Preeclampsia and Their Potential Association with Circulating Extracellular Vesicles during Pregnancy

Uncomplicated healthy pregnancy is the outcome of successful fertilization, implantation of embryos, trophoblast development and adequate placentation. Any deviation in these cascades of events may lead to complicated pregnancies such as preeclampsia (PE). The current incidence of PE is 2–8% in all pregnancies worldwide, leading to high maternal as well as perinatal mortality and morbidity rates. A number of randomized controlled clinical trials observed the association between low dose aspirin (LDA) treatment in early gestational age and significant reduction of early onset of PE in high-risk pregnant women. However, a substantial knowledge gap exists in identifying the particular mechanism of action of aspirin on placental function. It is already established that the placental-derived exosomes (PdE) are present in the maternal circulation from 6 weeks of gestation, and exosomes contain bioactive molecules such as proteins, lipids and RNA that are a “fingerprint” of their originating cells. Interestingly, levels of exosomes are higher in PE compared to normal pregnancies, and changes in the level of PdE during the first trimester may be used to classify women at risk for developing PE. The aim of this review is to discuss the mechanisms of action of LDA on placental and maternal physiological systems including the role of PdE in these phenomena. This review article will contribute to the in-depth understanding of LDA-induced PE prevention.

Thromboxane A synthase 1 gene expression and promotor haplotypes are associated with risk of large artery-atherosclerosis stroke in Iranian population

Large artery atherosclerosis (LAA) is known as an important cause of ischemic stroke (IS), which is a multifactorial disorder. Many candidate genes have been proposed for IS like (TBXAS1) that plays a significant role in LAA stroke pathogenesis. This is the first study on the evaluation of the association of the five single-nucleotide polymorphisms (SNPs) in TBXAS1 promoter region and the level of TBXAS1 transcript with large-artery atherosclerosis stroke. Five SNPs in TBXAS1 genes were investigated in 248 patients with large-artery atherosclerosis stroke and 199 healthy controls in Iranian population in this case-control study through using the high-resolution melting assay. In addition, the relationships between the selected SNPs with alteration of TBXAS1 gene expressions were investigated in terms of blood platelets through the reverse transcription-quantitative polymerase chain reaction. Multivariate logistic analysis with adjustments indicated that rs10256282CC, rs10237429CC, and rs4590360GG genotypes were associated with large-artery atherosclerosis stroke (adjusted odds ratio = 2.804, 2.872, and 2.432, respectively; P < 0.05, q < 0.05). Furthermore, the frequency of CACCG haplotype in the patients was greatly higher than that in the controls (OR = 1.424, 95% CI: 1.071-1.893, P = 0.014738). In addition, TBXAS1 expression was higher in patients compared to the controls (P = 0.021), and individuals with the homozygous mutated genotypes of these SNPs showed a higher expression level compared to other genotype (P < 0.05). In total, our findings indicate a significant association of TBXAS1 gene rs10256282CC, rs10237429CC, and rs4590360GG polymorphisms with large-artery atherosclerosis stroke susceptibility and the level of TBXAS1 expression, which was not previously reported in any population.

Obesity and laboratory aspirin resistance in high-risk pregnant women treated with low-dose aspirin

BACKGROUND

Low-dose aspirin is used for preeclampsia prevention in high-risk women, but the precise mechanism and optimal dose are unknown. Evidence suggests that an imbalance in prostacyclin and thromboxane A₂ (TXA₂) plays a key role in the pathogenesis of preeclampsia. Aspirin has a dose-dependent effect blocking production of TXA₂, a potent stimulator of platelet aggregation and promoter of vasoconstriction. Incomplete inhibition of platelet aggregation, designated aspirin resistance, can be reduced by increasing the aspirin dose. Evidence in the nonobstetric literature suggests that aspirin resistance may be more common among patients with a high body mass index.

OBJECTIVE

To investigate the association of obesity on platelet-derived thromboxane inhibition in high-risk women treated with low-dose aspirin.

MATERIALS AND METHODS

This was a secondary analysis of a prospective multi-centered study investigating the effect of low-dose aspirin (60-mg) administration in women at high risk for preeclampsia. Maternal serum TXB₂ (an indirect measure of TxA₂) levels were drawn at 3 time points: randomization (13-26 weeks' gestation), second trimester (at least 2 weeks after randomization and 24-28 weeks' gestation), and third trimester (34-38 weeks' gestation). Patients were included in the analysis if a TXB₂ level was recorded at randomization and at least 1 time point thereafter. Patients were stratified by body mass index category and treatment arm. Median TXB₂ levels were calculated at each time point, as well as rates of complete TXB₂ inhibition (<0.01 ng/mL). A multivariate logistic regression analysis was performed to generate odds ratios (OR) for complete TXB₂ inhibition by body mass index category, adjusting for maternal age, race, high-risk group at randomization, nulliparity, and rate of randomization less than 16 weeks' gestation.

RESULTS

A total of 1002 patients were included in the analysis, 496 (49.5%) and 506 (50.5%) in the low-dose aspirin and placebo groups respectively. There were substantial decreases in TXB₂ levels among low-dose aspirin-treated women in all body mass index categories. In contrast, women assigned to placebo did not show a marked decrease in TXB₂ levels after randomization, and obese women had higher median TXB₂ levels in both the second (16.5, interquartile range [IQR] 8.0-31.8 vs 14.0, IQR 6.9-26.7, ng/mL; P = .032) and third (15.7, IQR 7.6-28.5 vs 11.9, IQR 4.6-25.9, ng/mL; P = .043) trimesters. When comparing among stratified body mass index low-dose aspirin groups, women with class III obesity had the lowest odds of undetectable TXB₂ levels in the second trimester (adjusted odds ratio [aOR], 0.33; 95% confidence interval [CI], 0.15-0.72) and third trimester (aOR, 0.30; 95% CI, 0.11-0.78) as well as at both time points (aOR, 0.09; 95% CI, 0.02-0.41).

CONCLUSION

High-risk obese women receiving low-dose aspirin for the prevention of preeclampsia have lower rates of complete inhibition of TXB₂. These data suggest that an increase in aspirin dosing or frequency may be necessary in this population.

Can Yellow Stripe Scad Compete with Salmon on Its Role in Platelet Phospholipid Membrane and Its Cardiovascular Benefits?

This review article stresses the effective role of dietary fish fillet docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) on overweight as a risk factor of cardiovascular disease (CVD) via platelet phospholipid modification. Several reports have demonstrated that saturated fat in overweight evokes systemic inflammation and more importantly predisposes it to cardiovascular disorder. Prospective studies have shown that saturated fat is directly proportional to the level of arachidonic acids (AA), precursor of thromboxane in the platelet phospholipid membrane as omega-6 fatty acid in overweight and obese people. Some literature has demonstrated that omega-3 fatty acid from fish fillet ameliorates inflammation, reduces proinflammatory cytokine, inhibits signaling pathway, and regulates the physical composition of inflammatory leukocytes and free radicals (ROS). Yellow stripe scad (YSS) is a local Malaysian fish that has been shown to contain a comparable level of EPA/DHA content as observed in salmon. This review article will focus on the dietary role of fish fillet that will balance the omega-6 fatty acid/omega-3 fatty acid ratio in platelet phospholipid from YSS to manage and prevent healthy overweight/obesity-related risk factor of CVD and to avoid the risk orthodox drug treatment.

Definitions and pathophysiology of vasoplegic shock

Vasoplegia is the syndrome of pathological low systemic vascular resistance, the dominant clinical feature of which is reduced blood pressure in the presence of a normal or raised cardiac output. The vasoplegic syndrome is encountered in many clinical scenarios, including septic shock, post-cardiac bypass and after surgery, burns and trauma, but despite this, uniform clinical definitions are lacking, which renders translational research in this area challenging. We discuss the role of vasoplegia in these contexts and the criteria that are used to describe it are discussed. Intrinsic processes which may drive vasoplegia, such as nitric oxide, prostanoids, endothelin-1, hydrogen sulphide and reactive oxygen species production, are reviewed and potential for therapeutic intervention explored. Extrinsic drivers, including those mediated by glucocorticoid, catecholamine and vasopressin responsiveness of the blood vessels, are also discussed. The optimum balance between maintaining adequate systemic vascular resistance against the potentially deleterious effects of treatment with catecholamines is as yet unclear, but development of novel vasoactive agents may facilitate greater understanding of the role of the differing pathways in the development of vasoplegia. In turn, this may provide insights into the best way to care for patients with this common, multifactorial condition.

Associations between thromboxane A synthase 1 gene polymorphisms and the risk of ischemic stroke in a Chinese Han population

Thromboxane A synthase 1 (TBXAS1) catalyses the synthesis of thromboxane A2 (TXA2), which plays an important role in the pathogenesis of ischemic stroke. Thus, the TBXAS1 gene was investigated as a candidate gene involved in the formation of atherosclerosis. This case-control study collected peripheral blood specimens and clinical data of 370 ischemic stroke patients and 340 healthy controls in the Northern Chinese Han population from October 2010 to May 2011. Two TBXAS1 single-nucleotide polymorphisms, rs2267682 and rs10487667, were analyzed using a SNaPshot Multiplex sequencing assay to explore the relationships between the single-nucleotide polymorphisms in TBXAS1 and ischemic stroke. The TT genotype frequency and T allele frequency of rs2267682 in the patients with ischemic stroke were significantly higher than those in the controls (P < 0.01 and P = 0.02). Furthermore, compared with the GG + GT genotype, the TT rs2267682 genotype was associated with increased risk of ischemic stroke (odds ratio (OR) = 1.80, 95% confidence interval (CI): 1.16–2.79, P < 0.01). Multivariate logistic analysis with adjustments for confounding factors revealed that rs2267682 was still associated with ischemic stroke (OR = 1.94, 95% CI : 1.13–3.33, P = 0.02). The frequency of the T-G haplotype in the patients was significantly higher than that in the controls according haplotype analysis (OR = 1.49, 95% CI: 1.10–2.00, P < 0.01). These data reveal that the rs2267682 TBXAS1 polymorphism is associated with ischemic stroke. The TT genotype of TBXAS1 and T allele of rs2267682 increase susceptibility to ischemic stroke in this Northern Chinese Han population. The protocol has been registered with the Chinese Clinical Trial Registry (registration number: ChiCTR-COC-17013559).

PDE1A inhibition elicits cGMP-dependent relaxation of rat mesenteric arteries

BACKGROUND AND PURPOSE

PDE1, a subfamily of cyclic nucleotide PDEs consisting of three isoforms, PDE1A, PDE1B and PDE1C, has been implicated in the regulation of vascular tone. The PDE1 isoform(s) responsible for tone regulation is unknown. This study used isoform-preferring PDE1 inhibitors, Lu AF58027, Lu AF64196, Lu AF66896 and Lu AF67897, to investigate the relative contribution of PDE1 isoforms to regulation of vascular tone.

EXPERIMENTAL APPROACH

In rat mesenteric arteries, expression and localization of Pde1 isoforms were determined by quantitative PCR and in situ hybridization, and physiological impact of PDE1 inhibition was evaluated by isometric tension recordings.

KEY RESULTS

In rat mesenteric arteries, Pde1a mRNA expression was higher than Pde1b and Pde1c. In situ hybridization revealed localization of Pde1a to vascular smooth muscle cells (VSMCs) and only minor appearance of Pde1b and Pde1c. The potency of the PDE1 inhibitors at eliciting relaxation showed excellent correlation with their potency at inhibiting PDE1A. Thus, Lu AF58027 was the most potent at inhibiting PDE1A and was also the most potent at eliciting relaxation in mesenteric arteries. Inhibition of NOS with l-NAME, soluble GC with ODQ or PKG with Rp-8-Br-PET-cGMP all attenuated the inhibitory effect of PDE1 on relaxation, whereas PKA inhibition with H89 had no effect.

CONCLUSIONS AND IMPLICATIONS

Pde1a is the dominant PDE1 isoform present in VSMCs, and relaxation mediated by PDE1A inhibition is predominantly driven by enhanced cGMP signalling. These results imply that isoform-selective PDE1 inhibitors are powerful investigative tools allowing examination of physiological and pathological roles of PDE1 isoforms.

LPA1 receptor-mediated thromboxane A2 release is responsible for lysophosphatidic acid-induced vascular smooth muscle contraction

Lysophosphatidic acid (LPA) has been recognized recently as an endothelium-dependent vasodilator, but several lines of evidence indicate that it may also stimulate vascular smooth muscle cells (VSMCs), thereby contributing to vasoregulation and remodeling. In the present study, mRNA expression of all 6 LPA receptor genes was detected in murine aortic VSMCs, with the highest levels of LPA₁, LPA₂, LPA₄, and LPA₆ In endothelium-denuded thoracic aorta (TA) and abdominal aorta (AA) segments, 1-oleoyl-LPA and the LPA_1-3 agonist VPC31143 induced dose-dependent vasoconstriction. VPC31143-induced AA contraction was sensitive to pertussis toxin (PTX), the LPA_1&3 antagonist Ki16425, and genetic deletion of LPA₁ but not that of LPA₂ or inhibition of LPA₃, by diacylglycerol pyrophosphate. Surprisingly, vasoconstriction was also diminished in vessels lacking cyclooxygenase-1 [COX1 knockout (KO)] or the thromboxane prostanoid (TP) receptor (TP KO). VPC31143 increased thromboxane A₂ (TXA₂) release from TA of wild-type, TP-KO, and LPA₂-KO mice but not from LPA₁-KO or COX1-KO mice, and PTX blocked this effect. Our findings indicate that LPA causes vasoconstriction in VSMCs, mediated by LPA₁-, G_i-, and COX1-dependent autocrine/paracrine TXA₂ release and consequent TP activation. We propose that this new-found interaction between the LPA/LPA₁ and TXA₂/TP pathways plays significant roles in vasoregulation, hemostasis, thrombosis, and vascular remodeling.-Dancs, P. T., Ruisanchez, E., Balogh, A., Panta, C. R., Miklós, Z., Nüsing, R. M., Aoki, J., Chun, J., Offermanns, S., Tigyi, G., Benyó, Z. LPA₁ receptor-mediated thromboxane A₂ release is responsible for lysophosphatidic acid-induced vascular smooth muscle contraction.

Docosahexaenoic Acid Supplemented Diet Influences the Orchidectomy-Induced Vascular Dysfunction in Rat Mesenteric Arteries

Over the past few decades, the cardiovascular benefits of a high dietary intake of long-chain polyunsaturated fatty acids (PUFAs), like docosahexaenoic acid (DHA), have been extensively studied. However, many of the molecular mechanisms and effects exerted by PUFAs have yet to be well explained. The lack of sex hormones alters vascular tone, and we have described that a DHA-supplemented diet to orchidectomized rats improve vascular function of the aorta. Based on these data and since the mesenteric artery importantly controls the systemic vascular resistance, the objective of this study was to analyze the effect of a DHA-supplemented diet on the mesenteric vascular function from orchidectomized rats. For this purpose mesenteric artery segments obtained from control, orchidectomized or orchidectomized plus DHA-supplemented diet were utilized to analyze: (1) the release of prostanoids, (2) formation of NO and ROS, (3) the vasodilator response to acetylcholine (ACh), as well as the involvement of prostanoids and NO in this response, and (4) the vasoconstrictor response to electrical field stimulation (EFS), analyzing also the effect of exogenous noradrenaline (NA), and the NO donor, sodium nitroprusside (SNP). The results demonstrate beneficial effects of DHA on the vascular function in orchidectomized rats, which include a decrease in the prostanoids release and superoxide formation that were previously augmented by orchidectomy. Additionally, there was an increase in endothelial NO formation and the response to ACh, in which NO involvement and the participation of vasodilator prostanoids were increased. DHA also reversed the decrease in EFS-induced response caused by orchidectomy. All of these findings suggest beneficial effects of DHA on vascular function by reversing the neurogenic response and the endothelial dysfunction caused by orchidectomy.

Effects of estrogen on cerebrovascular function: age-dependent shifts from beneficial to detrimental in small cerebral arteries of the rat

In the present study, interactions of age and estrogen in the modulation of cerebrovascular function were examined in small arteries <150 μM. The hypothesis tested was that age enhances deleterious effects of exogenous estrogen by augmenting constrictor prostanoid (CP)-potentiated reactivity of the female (F) cerebrovasculature. F Sprague-Dawley rats approximating key stages of "hormonal aging" in humans were studied: perimenopausal (mature multi-gravid, MA, cyclic, 5-6 mo of age) and postmenopausal (reproductively senescent, RS, acyclic 10-12 mo of age). Rats underwent bilateral ovariectomy and were given estrogen replacement therapy (E) or placebo (O) for 14-21 days. Vasopressin reactivity (VP, 10(-12)-10(-7) M) was measured in pressurized middle cerebral artery segments, alone or in the presence of COX-1- (SC560, 1 μM) or COX-2- (NS398, 10 μM) selective inhibitors. VP-stimulated release of prostacyclin (PGI2) and thromboxane (TXA2) were assessed by radioimmunoassay of 6-keto-PGF1α and TXB2 (stable metabolites). VP-induced vasoconstriction was attenuated in ovariectomized + estrogen-replaced, multigravid adult rats (5-6 mo; MAE) but potentiated in older ovariectomized + estrogen-replaced, reproductively senescent rats (12-14 mo; RSE). SC560 and NS398 reduced reactivity similarly in ovariectomized multigravid adult rats (5-6 mo; MAO) and ovariectomized reproductively senescent rat (12-14 mo; RSO). In MAE, reactivity to VP was reduced to a greater extent by SC560 than by NS398; however, in RSE, this effect was reversed. VP-stimulated PGI2 was increased by estrogen, yet reduced by age. VP-stimulated TXA2 was increased by estrogen and age in RSE but did not differ in MAO and RSO. Taken together, these data reveal that the vascular effects of estrogen are distinctly age-dependent in F rats. In younger MA, beneficial and protective effects of estrogen are evident (decreased vasoconstriction, increased dilator prostanoid function). Conversely, in older RS, detrimental effects of estrogen begin to be manifested (enhanced vasoconstriction and CP function). These findings may lead to age-specific estrogen replacement therapies that maximize beneficial and minimize detrimental effects of this hormone on small cerebral arteries that regulate blood flow.

Lack of Thromboxane Synthase Prevents Hypertension and Fetal Growth Restriction after High Salt Treatment during Pregnancy

Preeclampsia (PE) is a potentially fatal pregnancy-related hypertensive disorder characterized by poor placenta development that can cause fetal growth restriction. PE-associated pathologies, including thrombosis, hypertension, and impaired placental development, may result from imbalances between thromboxane A₂ (TXA₂) and prostacyclin. Low-dose aspirin, which selectively inhibits TXA₂ production, is used to prevent high-risk PE. However, the role of TXA₂ in aspirin-mediated protective effects in women with PE is not understood fully. In this study, we examined the role of prostanoids in PE using human samples and an induced PE mouse model. We demonstrated that the administration of salted drinking water (2.7% NaCl) to wild-type mice resulted in elevated placental TXA₂ synthase (TXAS) and plasma TXA₂, but not prostacyclin, levels, which was also found in our clinical PE placenta samples. The high salt-treated wild-type pregnant mice had shown unchanged maternal body weight, hypertension (MAP increase 15 mmHg), and decreased pup weight (~50%) and size (~24%), but these adverse effects were ameliorated in TXAS knockout (KO) mice. Moreover, increased expression of interleukin-1β and downstream phosphorylated-p38-mitogen-activated protein kinase were concordant with apoptosis induction in the placentas of salt water-treated wild-type mice. These alterations were not observed in TXAS KO mice. Together, our data suggest that TXA₂ depletion has anti-PE effects due to the prevention of hypertension and placental damage through downregulation of the interleukin-1β pathway.

Endothelial cell regulation of pulmonary vascular tone, inflammation, and coagulation

The pulmonary endothelium represents a heterogeneous cell monolayer covering the luminal surface of the entire lung vasculature. As such, this cell layer lies at a critical interface between the blood, airways, and lung parenchyma, and must act as a selective barrier between these diverse compartments. Lung endothelial cells are able to produce and secrete mediators, display surface receptor, and cellular adhesion molecules, and metabolize circulating hormones to influence vasomotor tone, both local and systemic inflammation, and coagulation functions. In this review, we will explore the role of the pulmonary endothelium in each of these systems, highlighting key regulatory functions of the pulmonary endothelial cell, as well as novel aspects of the pulmonary endothelium in contrast to the systemic cell type. The interactions between pulmonary endothelial cells and both leukocytes and platelets will be discussed in detail, and wherever possible, elements of endothelial control over physiological and pathophysiological processes will be examined.

Endothelial dysfunction in rats with ligature-induced periodontitis: Participation of nitric oxide and cycloxygenase-2-derived products

OBJECTIVES

Considering the evident relationship between periodontitis and cardiovascular diseases in humans, we aimed to study the in vitro vascular reactivity of aorta rings prepared from rats with ligature-induced periodontitis.

METHODS

Seven days after the induction of unilateral periodontitis, the animals were euthanised; rings were prepared from the descending abdominal aortas and mounted in tissue baths for the in vitro measurement of the isometric force responses to norepinephrine (NE) and acetylcholine (ACh), as well as in the presence of inhibitors of nitric oxide synthase (NOS) and cycloxygenase (COX) isoenzymes. Aortic COX and NOS gene expressions were analysed by RT-PCR, as well as protein COX-2 expression by Western blot.

RESULTS

Periodontitis resulted in significant alveolar bone loss and did not affect arterial pressure. However, both NE-induced contraction and ACh-induced relaxation were significantly decreased and related to the presence of endothelium. Diminished eNOS and augmented COX-2 and iNOS expressions were found in the aortas from rats with periodontitis, and the pharmacological inhibition of COX-2 or iNOS improved the observed vasomotor deficiencies.

CONCLUSIONS

We can thus conclude that periodontitis induces significant endothelial dysfunction in rat aorta which is characterized by decreased eNOS expression and mediated by upregulated iNOS and COX-2 products.

Alteration of actin dependent signaling pathways associated with membrane microdomains in hyperlipidemia

Background

Membrane microdomains represent dynamic membrane nano-assemblies enriched in signaling molecules suggesting their active involvement in not only physiological but also pathological molecular processes. The hyperlipidemic stress is a major risk factor of atherosclerosis, but its exact mechanisms of action at the membrane microdomains level remain elusive. The aim of the present study was to determine whether membrane-cytoskeleton proteome in the pulmonary tissue could be modulated by the hyperlipidemic stress, a major risk factor of atherosclerosis.

Results

High resolution mass spectrometry based proteomics analysis was performed for detergent resistant membrane microdomains isolated from lung homogenates of control, ApoE deficient and statin treated ApoE deficient mice. The findings of the study allowed the identification with high confidence of 1925 proteins, 291 of which were found significantly altered by the modified genetic background, by the statin treatment or both conditions. Principal component analysis revealed a proximal partitioning of the biological replicates, but also a distinct spatial scattering of the sample groups, highlighting different quantitative profiles. The statistical significant over-representation of Regulation of actin cytoskeleton, Focal adhesion and Adherens junction Kyoto Encyclopedia of Genes and Genomes signaling pathways was demonstrated through bioinformatics analysis. The three inter-relation maps comprised 29 of regulated proteins, proving membrane-cytoskeleton coupling targeting and alteration by hyperlipidemia and/or statin treatment.

Conclusions

The findings of the study allowed the identification with high confidence of the main proteins modulated by the hyperlipidemic stress involved in the actin-dependent pathways. Our study provides the basis for future work probing how the protein activities at the membrane-cytoskeleton interface are dependent upon genetic induced hyperlipidemia.

Electronic supplementary material

The online version of this article (doi:10.1186/s12953-015-0087-0) contains supplementary material, which is available to authorized users.

Effect of Dietary Docosahexaenoic Acid Supplementation on the Participation of Vasodilator Factors in Aorta from Orchidectomized Rats

Benefits of n-3 polyunsaturated fatty acids (PUFAs) against cardiovascular diseases have been reported. Vascular tone regulation is largely mediated by endothelial factors whose release is modulated by sex hormones. Since the incidence of cardiovascular pathologies has been correlated with decreased levels of sex hormones, the aim of this study was to analyze whether a diet supplemented with the specific PUFA docosahexaenoic acid (DHA) could prevent vascular changes induced by an impaired gonadal function. For this purpose, control and orchidectomized rats were fed with a standard diet supplemented with 5% (w/w) sunflower oil or with 3% (w/w) sunflower oil plus 2% (w/w) DHA. The lipid profile, the blood pressure, the production of prostanoids and nitric oxide (NO), and the redox status of biological samples from control and orchidectomized rats, fed control or DHA-supplemented diet, were analyzed. The vasodilator response and the contribution of NO, prostanoids and hyperpolarizing mechanisms were also studied. The results showed that orchidectomy negatively affected the lipid profile, increased the production of prostanoids and reactive oxygen species (ROS), and decreased NO production and the antioxidant capacity, as well as the participation of hyperpolarizing mechanisms in the vasodilator responses. The DHA-supplemented diet of the orchidectomized rats decreased the release of prostanoids and ROS, while increasing NO production and the antioxidant capacity, and it also improved the lipid profile. Additionally, it restored the participation of hyperpolarizing mechanisms by activating potassium. Since the modifications induced by the DHA-supplemented diet were observed in the orchidectomized, but not in the healthy group, DHA seems to exert cardioprotective effects in physiopathological situations in which vascular dysfunction exists.

Endothelial Mineralocorticoid Receptors Differentially Contribute to Coronary and Mesenteric Vascular Function Without Modulating Blood Pressure

Arteriolar vasoreactivity tightly regulates tissue-specific blood flow and contributes to systemic blood pressure (BP) but becomes dysfunctional in the setting of cardiovascular disease. The mineralocorticoid receptor (MR) is known to regulate BP via the kidney and by vasoconstriction in smooth muscle cells. Although endothelial cells (EC) express MR, the contribution of EC-MR to BP and resistance vessel function remains unclear. To address this, we created a mouse with MR specifically deleted from EC (EC-MR knockout [EC-MR-KO]) but with intact leukocyte MR expression and normal renal MR function. Telemetric BP studies reveal no difference between male EC-MR-KO mice and MR-intact littermates in systolic, diastolic, circadian, or salt-sensitive BP or in the hypertensive responses to aldosterone±salt or angiotensin II±l-nitroarginine methyl ester. Vessel myography demonstrated normal vasorelaxation in mesenteric and coronary arterioles from EC-MR-KO mice. After exposure to angiotensin II-induced hypertension, impaired endothelial-dependent relaxation was prevented in EC-MR-KO mice in mesenteric vessels but not in coronary vessels. Mesenteric vessels from angiotensin II-exposed EC-MR-KO mice showed increased maximum responsiveness to acetylcholine when compared with MR-intact vessels, a difference that is lost with indomethacin+l-nitroarginine methyl ester pretreatment. These data support that EC-MR plays a role in regulating endothelial function in hypertension. Although there was no effect of EC-MR deletion on mesenteric vasoconstriction, coronary arterioles from EC-MR-KO mice showed decreased constriction to endothelin-1 and thromboxane agonist at baseline and also after exposure to hypertension. These data support that EC-MR participates in regulation of vasomotor function in a vascular bed-specific manner that is also modulated by risk factors, such as hypertension.

The effect of kisspeptin on the regulation of vascular tone

Kisspeptin has been implicated in cardiovascular control. Eicosanoids play a crucial role in the activation of platelets and the regulation of vascular tone. In the present study, we investigated the effect of kisspeptins on eicosanoid synthesis in platelets and aorta in vitro. Platelets and aorta were isolated from Wistar–Kyoto rats. After preincubation with different doses of kisspeptin, samples were incubated with [1-14C]arachidonic acid (0.172 pmol/mL) in tissue culture Medium 199. The amount of labeled eicosanoids was measured with liquid scintillation, after separation with overpressure thin-layer chromatography. Kisspeptin-13 stimulated the thromboxane synthesis. The dose–response curve was bell-shaped and the most effective concentration was 2.5 × 10−8 mol/L, inducing a 27% increase. Lipoxygenase products of platelets displayed a dose-dependent elevation up to the dose of 5 × 10−8 mol/L. In the aorta, kisspeptin-13 induced a marked elevation in the production of 6-keto-prostaglandin F1α, the stable metabolite of prostacyclin, and lipoxygenase products. Different effects of kisspeptin on cyclooxygenase and lipoxygenase products indicate that beyond intracellular Ca2+ mobilization, other signaling pathways might also contribute to its actions. Our data suggest that kisspeptin, through the alteration of eicosanoid synthesis in platelets and aorta, may play a physiologic and (or) pathologic role in the regulation of vascular tone.

Curcumin and major depression: a randomised, double-blind, placebo-controlled trial investigating the potential of peripheral biomarkers to predict treatment response and antidepressant mechanisms of change

A recent randomised, double-blind, placebo controlled study conducted by our research group, provided partial support for the efficacy of supplementation with a patented curcumin extract (500 mg, twice daily) for 8 weeks in reducing depressive symptoms in people with major depressive disorder. In the present paper, a secondary, exploratory analysis of salivary, urinary and blood biomarkers collected during this study was conducted to identify potential antidepressant mechanisms of action of curcumin. Pre and post-intervention samples were provided by 50 participants diagnosed with major depressive disorder, and the Inventory of Depressive Symptomatology self-rated version (IDS-SR30) was used as the primary depression outcome measure. Compared to placebo, 8 weeks of curcumin supplementation was associated with elevations in urinary thromboxane B2 (p<0.05), and substance P (p<0.001); while placebo supplementation was associated with reductions in aldosterone (p<0.05) and cortisol (p<0.05). Higher baseline plasma endothelin-1 (rs=-0.587; p<0.01) and leptin (rs=-0.470; p<0.05) in curcumin-treated individuals was associated with greater reductions in IDS-SR30 score after 8 weeks of treatment. Our findings demonstrate that curcumin supplementation influences several biomarkers that may be associated with its antidepressant mechanisms of action. Plasma concentrations of leptin and endothelin-1 seem to have particular relevance to treatment outcome. Further investigations using larger samples sizes are required to elucidate these findings, as the multiple statistical comparisons completed in this study increased the risk of type I errors.

Endothelin-1-mediated vasoconstriction alters cerebral gene expression in iron homeostasis and eicosanoid metabolism

Endothelins are potent vasoconstrictors and signaling molecules. Their effects are broad, impacting processes ranging from neurovascular and cardiovascular health to cell migration and survival. In stroke, traumatic brain injury or subarachnoid hemorrhage, endothelin-1 (ET-1) is induced resulting in cerebral vasospasm, ischemia, reperfusion and the activation of various pathways. Given the central role that ET-1 plays in these patients and to identify the downstream molecular events specific to transient vasoconstriction, we studied the consequences of ET-1-mediated vasoconstriction of the middle cerebral artery in a rat model. Our observations demonstrate that ET-1 can lead to increases in gene expression, including genes associated with the inflammatory response (Ifnb, Il6, Tnf) and oxidative stress (Hif1a, Myc, Sod2). We also observed inductions (>2 fold) of genes involved in eicosanoid biosynthesis (Pla2g4a, Pla2g4b, Ptgs2, Ptgis, Alox12, Alox15), heme metabolism (Hpx, Hmox1, Prdx1) and iron homeostasis (Hamp, Tf). Our findings demonstrate that mRNA levels for the hormone hepcidin (Hamp) are induced in the brain in response to ET-1, providing a novel target in the treatment of multiple conditions. These changes on the ipsilateral side were also accompanied by corresponding changes in a subset of genes in the contralateral hemisphere. Understanding ET-1-mediated events at the molecular level may lead to better treatments for neurological diseases and provide significant impact on neurological function, morbidity and mortality.

Hydrogen peroxide elicits constriction of skeletal muscle arterioles by activating the arachidonic acid pathway

Aims

The molecular mechanisms of the vasoconstrictor responses evoked by hydrogen peroxide (H₂O₂) have not been clearly elucidated in skeletal muscle arterioles.

Methods and Results

Changes in diameter of isolated, cannulated and pressurized gracilis muscle arterioles (GAs) of Wistar-Kyoto rats were determined under various test conditions. H₂O₂ (10–100 µM) evoked concentration-dependent constrictions in the GAs, which were inhibited by endothelium removal, or by antagonists of phospholipase A (PLA; 100 µM 7,7-dimethyl-(5Z,8Z)-eicosadienoic acid), protein kinase C (PKC; 10 µM chelerythrine), phospholipase C (PLC; 10 µM U-73122), or Src family tyrosine kinase (Src kinase; 1 µM Src Inhibitor-1). Antagonists of thromboxane A2 (TXA2; 1 µM SQ-29548) or the non-specific cyclooxygenase (COX) inhibitor indomethacin (10 µM) converted constrictions to dilations. The COX-1 inhibitor (SC-560, 1 µM) demonstrated a greater reduction in constriction and conversion to dilation than that of COX-2 (celecoxib, 3 µM). H₂O₂ did not elicit significant changes in arteriolar Ca²⁺ levels measured with Fura-2.

Conclusions

These data suggest that H₂O₂ activates the endothelial Src kinase/PLC/PKC/PLA pathway, ultimately leading to the synthesis and release of TXA2 by COX-1, thereby increasing the Ca²⁺ sensitivity of the vascular smooth muscle cells and eliciting constriction in rat skeletal muscle arterioles.

Time-dependent effect of orchidectomy on vascular nitric oxide and thromboxane A2 release. Functional implications to control cell proliferation through activation of the epidermal growth factor receptor

This study analyzes whether the release of nitric oxide (NO) and thromboxane A2 (TXA2) depends on the time lapsed since gonadal function is lost, and their correlation with the proliferation of vascular smooth muscle cells (VSMC) mediated by the epidermal growth factor receptor (EGFR). For this purpose, aortic and mesenteric artery segments from control and 6-weeks or 5-months orchidectomized rats were used to measure NO and TXA2 release. The results showed that the basal and acetylcholine (ACh)-induced NO release were decreased 6 weeks post-orchidectomy both in aorta and mesenteric artery, but were recovered 5 months thereafter up to levels similar to those found in arteries from control rats. The basal and ACh-induced TXA2 release increased in aorta and mesenteric artery 6 weeks post-orchidectomy, and was maintained at high levels 5 months thereafter. Since we previously observed that orchidectomy, which decreased testosterone level, enlarged the muscular layer of mesenteric arteries, the effect of testosterone on VSMC proliferation was analyzed. The results showed that treatment of cultured VSMC with testosterone downregulated mitogenic signaling pathways initiated by the ligand-dependent activation of the EGFR. In contrast, the EGFR pathways were constitutively active in mesenteric arteries of long-term orchidectomized rats. Thus, the exposure of mesenteric arteries from control rats to epidermal growth factor (EGF) induced the activation of EGFR signaling pathways. However, the addition of EGF to arteries from orchidectomized rats failed to induce a further activation of these pathways. In conclusion, this study shows that the release of NO depends on the time lapsed since the gonadal function is lost, while the release of TXA2 is already increased after short periods post-orchidectomy. The alterations in these signaling molecules could contribute to the constitutive activation of the EGFR and its downstream signaling pathways after long period post-orchidectomy enhancing the proliferation of the vascular muscular layer.

Blockade of endothelin ET(A), but not thromboxane, receptors offsets the cyclosporine-evoked hypertension and interrelated baroreflex and vascular dysfunctions

The impairment of arterial baroreceptor and vasodilator functions are two major contributors to the hypertensive action of cyclosporine (CSA). In this study, in vivo and in vitro pharmacological studies were performed to investigate whether these effects of CSA are differentially modulated by endothelin and thromboxane signaling. The treatment of rats with CSA (25mg/kg/day i.p.) for 7 consecutive days caused significant increases in blood pressure (BP), attenuated reflex heart rate (HR) responses to vasopressor (phenylephrine, PE) and vasodepressor (sodium nitroprusside, SNP) agents, and reduced cumulative vasorelaxant responses elicited by acetylcholine (Ach, 1×10(-9)-1×10(-5)M) in PE-precontracted isolated aortas. These effects of CSA were blunted after concurrent i.p. administration of atrasentan (selective ETA blocker, 10mg/kg/day), but not terutroban (thromboxane receptor blocker, 10mg/kg/day). Moreover, atrasentan reversed the reductions in aortic protein expression of eNOS caused by CSA whereas terutroban was without effect. We also report that the favorable effect of atrasentan on CSA-evoked impairment in aortic Ach responsiveness disappeared in rats treated simultaneously with L-NAME (NOS inhibitor, 10mg/kg/day) but not BQ 788 (ETB receptor blocker, 0.1mg/kg/day) or indomethacin (cycloxygenase inhibitor, 5mg/kg/day). Together, the data implicate endothelin ETA receptors in baroreflex and vascular derangements which predispose to the hypertensive effect of CSA. Moreover, the facilitation of NOS, but not ETB receptors or cycloxygenase-derived prostanoids, signaling is pivotal for advantageous effect of atrasentan on the aortic CSA-Ach interaction.

Physiology of hemodynamic homeostasis

Homeostasis of hemodynamics refers to the regulation of the blood circulation to meet the demands of the different organ and tissue systems. This homeostasis involves an intimate interaction between peripheral metabolic needs, vascular adaptations to meet these needs and cardiac adaptation to provide the driving force to circulate the blood. The three variables that reflect the homeostasis of cardiovascular regulation are mean systemic arterial pressure, cardiac output and total systemic vascular resistance in the circulation. Regulation of the blood circulation depends on a static component, based on the physical properties of the different vessels and the characteristics of the fluid going through these vessels. Superimposed on this static regulation, is the dynamic regulation which is based on local control systems and the controls systems that adjust hemodynamic status to meet the needs of the body as a whole. This global circulation throughout the body is regulated by hormonal and neural control systems. All these systems closely interact to maintain blood pressure between the normal levels.

Thromboxane A synthase-independent production of 12-hydroxyheptadecatrienoic acid, a BLT2 ligand

12(S)-hydroxyheptadeca-5Z,8E,10E-trienoic acid (12-HHT) has long been considered a by-product of thromboxane A₂ (TxA₂) biosynthesis with no biological activity. Recently, we reported 12-HHT to be an endogenous ligand for BLT2, a low-affinity leukotriene B4 receptor. To delineate the biosynthetic pathway of 12-HHT, we established a method that enables us to quantify various eicosanoids and 12-HHT using LC-MS/MS analysis. During blood coagulation, 12-HHT levels increased in a time-dependent manner and were relatively higher than those of TxB₂, a stable metabolite of TxA₂. TxB₂ production was almost completely inhibited by treatment with ozagrel, an inhibitor of TxA synthase (TxAS), while 12-HHT production was inhibited by 80-90%. Ozagrel-treated blood also exhibited accumulation of PGD₂ and PGE₂, possibly resulting from the shunting of PGH₂ into synthetic pathways for these prostaglandins. In TxAS-deficient mice, TxB₂ production during blood coagulation was completely lost, but 12-HHT production was reduced by 80-85%. HEK293 cells transiently expressing TxAS together with cyclooxygenase (COX)-1 or COX-2 produced both TxB₂ and 12-HHT from arachidonic acid, while HEK293 cells expressing only COX-1 or COX-2 produced significant amounts of 12-HHT but no TxB₂. These results clearly demonstrate that 12-HHT is produced by both TxAS-dependent and TxAS-independent pathways in vitro and in vivo.

Ischemic postconditioning during reperfusion attenuates intestinal injury and mucosal cell apoptosis by inhibiting JAK/STAT signaling activation

The present study attempts to evaluate the role of Janus kinase/signal transducer and activator of transcription (JAK/STAT) signaling in intestinal ischemia/reperfusion (I/R)-induced intestinal injury and whether immediate ischemic postconditioning ameliorates intestinal injury via attenuation of intestinal mucosal apoptosis subsequent to inhibiting JAK/STAT signaling activation. Anesthetized adult male Sprague-Dawley rats were subjected to superior mesenteric artery occlusion consisting of 60 min of ischemia and 2 h of reperfusion; sham laparotomy served as controls. Animals received either subcutaneous administration of JAK2 inhibitor (AG490, 8 mg/kg) or STAT inhibitor (rapamycin, 0.4 mg/kg) 30 min before ischemia. Ischemic postconditioning was performed by three cycles of 30-s reperfusion and 30-s ischemia initiated immediately upon reperfusion. It was found that intestinal I/R resulted in conspicuous intestinal injury evidenced by significant increases in Chiu's score, lactic acid, and diamine oxidase activity, accompanied with increases in plasma levels of 15-F2t-isoprostane, endothelin 1, and thromboxane B2, as well as increase in the intestinal tissue myeloperoxidase activity. Meanwhile, the apoptotic index and cleaved caspase 3, phosphorylated JAK2, phosphorylated STAT1, and phosphorylated STAT3 expression were significantly enhanced versus sham control. Both ischemic postconditioning and pretreatment with AG490 or rapamycin significantly attenuated all the above changes. These results indicate that JAK/STAT pathway activation plays a critical role in I/R-induced intestinal injury, which is associated with increased oxidative stress, neutrophil accumulation, intestinal mucosal apoptosis, and microcirculation disturbance. Ischemic postconditioning mediates attenuation of intestinal I/R injury, and cell apoptosis may be attributable to the JAK/STAT signaling inhibition.

Aging enhances contraction to thromboxane A2 in aorta from female senescence-accelerated mice

The time-course for aging-associated effects on vascular reactivity to U46619, a stable analogue of thromboxane A(2) (TXA(2)), was studied in aorta from female senescence-accelerated mice-prone (SAMP8), a murine model of accelerated senescence. SAMP8 and senescence-accelerated mice-resistant (SAMR1) were divided into three groups: 3-, 6- and 10-month-old. Contractile curves to U46619 (10(-9) to 10(-6) M) were performed in aortic rings in the absence or in the presence of nitric oxide synthase (NOS) inhibitor N(G)-nitro-L-arginine methyl ester (L-NAME; 10(-4) M) and/or cyclooxygenase (COX) inhibitor indomethacin (10(-5) M). Protein and gene expression for COX-1 and COX-2 were determined by immunofluorescence and real-time PCR, respectively. Maximal contraction to U46619 was markedly higher in SAMP8 at all ages. In SAMR1, increases were seen at 10 months, while SAMP8 displays augmented contraction at 6 months, which was further increased at 10 months. L-NAME enhanced U46619 contractions in both 6-month-old groups, although the increase was higher on vessels from SAMR1 at this age. Indomethacin equally increased U46619 contractions in both 3-month-old groups, suggesting the production of vasodilator prostaglandin in young animals. In contrast, at 6 and 10 months indomethacin decreased U46619 contractions in both groups, indicating an aging-associated swap to a release of contractile prostanoids in aorta. In conclusion, aging enhances contractile responses to TXA(2) in aorta from female mice by a mechanism involving a decrease of NO production and increased action of contractile prostanoids. This process occurs earlier in SAMP8 mice, establishing these mice as good model to study cardiovascular aging in a convenient and standard time-course.

Fish oil and inflammatory status alter the n-3 to n-6 balance of the endocannabinoid and oxylipin metabolomes in mouse plasma and tissues

It is well established that dietary intake of n-3 fatty acids is associated with anti-inflammatory effects, and this has been linked to modulation of the oxylipin and endocannabinoid metabolomes. However, the amount of data on specific tissue effects is limited, and it is not known how inflammation affects this relation. In the present study we systematically explored the combined effects of n-3 fatty acid diets and inflammation on the in vivo endocannabinoid and oxylipin metabolomes using a multicompartment, detailed targeted lipidomics approach. Male C57BL/6 mice received diets containing 0, 1, or 3 % w/w fish oil (FO) for 6 weeks, after which 2 mg/kg LPS or saline was administered i.p. Levels of endocannabinoids/N-acylethanolamines (NAEs) and oxylipins, covering n-3 and n-6 fatty acid derived compounds, were determined in plasma, liver, ileum and adipose tissue using LC-MS/MS. FO generally increased 'n-3' NAEs and oxylipins at the expense of compounds derived from other fatty acids, affecting all branches of the oxylipin metabolome. LPS generally increased levels of endocannabinoids/NAEs and oxylipins, with opposing effects across plasma and tissues. Multivariate data analysis revealed that separation between diet groups in the saline treated groups was primarily explained by decreases in other than n-3 derived compounds. In the LPS treated groups, the separation was primarily explained by increases in n-3 derived compounds. In conclusion, FO caused marked changes in the n-3 to n-6 balance of the endocannabinoid and oxylipin metabolomes, with specific effects depending on inflammatory status. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s11306-012-0421-9) contains supplementary material, which is available to authorized users.

Health implications of high dietary omega-6 polyunsaturated Fatty acids

Omega-6 (n-6) polyunsaturated fatty acids (PUFA) (e.g., arachidonic acid (AA)) and omega-3 (n-3) PUFA (e.g., eicosapentaenoic acid (EPA)) are precursors to potent lipid mediator signalling molecules, termed "eicosanoids," which have important roles in the regulation of inflammation. In general, eicosanoids derived from n-6 PUFA are proinflammatory while eicosanoids derived from n-3 PUFA are anti-inflammatory. Dietary changes over the past few decades in the intake of n-6 and n-3 PUFA show striking increases in the (n-6) to (n-3) ratio (~15 : 1), which are associated with greater metabolism of the n-6 PUFA compared with n-3 PUFA. Coinciding with this increase in the ratio of (n-6) : (n-3) PUFA are increases in chronic inflammatory diseases such as nonalcoholic fatty liver disease (NAFLD), cardiovascular disease, obesity, inflammatory bowel disease (IBD), rheumatoid arthritis, and Alzheimer's disease (AD). By increasing the ratio of (n-3) : (n-6) PUFA in the Western diet, reductions may be achieved in the incidence of these chronic inflammatory diseases.

Pulmonary hypertension in canine degenerative mitral valve disease

Pulmonary hypertension secondary to degenerative mitral valve disease has been recognized clinically for many years in veterinary medicine, and clinical diagnosis of this syndrome in dogs has been enhanced greatly by widespread use of echocardiography and Doppler echocardiography. Medical therapy is now available to treat this clinical complication of mitral valve disease, making timely diagnosis even more important to patient longevity and quality of life.