How is the human umbilical artery regulated?

Citral relaxes umbilical vessels of normotensive and preeclamptic parturients

INTRODUCTION

Citral is a low-toxicity monoterpene that has a vasodilator effect on various smooth muscles, and The present study aimed to evaluate its vasorelaxant effect on umbilical vessels of normotensive parturients (NTP) and with preeclampsia parturients (PEP).

METHOD

Segments of human umbilical artery (HUA) and vein (HUV) of NTP or PEP were mounted in a bath to record the force of contraction, under tension of 3.0 gf and contracted with the contracting agents: K+ (60 mM), 5 -HT (10 μM) and Ba2+ (1-30 mM). Next, the effect of citral (1-3000 μM) on these contractions and on basal tone was evaluated.

RESULTS

In HUA and HUV, citral (1-1000 μM), in NTP condition, inhibited contractions evoked by K+ (IC50 of 413.5 and 271.3, respectively) and by 5-HT (IC50 of 164.8 and 574.3). In the PEP condition, in HUA and HUV, citral also inhibited the contractions evoked by K+ (IC50 of 363.3 and 218.3, respectively) and 5-HT (IC50 of 432.1 and 520.4). At a concentration of 1000 μM, citral completely or almost completely (>90 %) inhibited all contractions. At a concentration of 100-1000 μM, citral, in general, was already able to reduce the contraction induced by 1-3 mM Ba2+ in both AUH and VUH, under NTP and PEP conditions.

DISCUSSION

Citral has been shown to be an effective HUA and HUV vasodilator in NTP and PEP. As its toxicity is low, it suggests that this substance can be considered a potential therapeutic agent.

Fetal sex and the relative reactivity of human umbilical vein and arteries are key determinants in potential beneficial effects of phosphodiesterase inhibitors

Intrauterine growth restriction (IUGR) is a common complication of pregnancy. We previously demonstrated that IUGR is associated with an impaired nitric oxide (NO)-induced relaxation in the human umbilical vein (HUV) of growth-restricted females compared to appropriate for gestational age (AGA) newborns. We found that phosphodiesterase (PDE) inhibition improved NO-induced relaxation in HUV, suggesting that PDEs could represent promising targets for therapeutic intervention. This study aimed to investigate the effects of PDE inhibition on human umbilical arteries (HUAs) compared to HUV. Umbilical vessels were collected in IUGR and AGA term newborns. NO-induced relaxation was studied using isolated vessel tension experiments in the presence or absence of the nonspecific PDE inhibitor 3-isobutyl-1-methylxanthine (IBMX). PDE1B, PDE1C, PDE3A, PDE4B, and PDE5A were investigated by Western blot. NO-induced vasodilation was similar between IUGR and AGA HUAs. In HUAs precontracted with serotonin, IBMX enhanced NO-induced relaxation only in IUGR females, whereas in HUV IBMX increased NO-induced relaxation in all groups except IUGR males. In umbilical vessels preconstricted with the thromboxane A2 analog U46619, IBMX improved NO-induced relaxation in all groups to a greater extent in HUV than HUAs. However, the PDE protein content was higher in HUAs than HUV in all study groups. Therefore, the effects of PDE inhibition depend on the presence of IUGR, fetal sex, vessel type, and vasoconstrictors implicated. Despite a higher PDE protein content, HUAs are less sensitive to IBMX than HUV, which could lead to adverse effects of PDE inhibition in vivo by impairment of the fetoplacental hemodynamics.NEW & NOTEWORTHY The effects of phosphodiesterase inhibition on the umbilical circulation depend on the presence of intrauterine growth restriction, the fetal sex, vessel type, and vasoconstrictors implicated. The human umbilical vascular tone regulation is complex and depends on the amount and activity of specific proteins but also probably on the subcellular organization mediating protein interactions. Therefore, therapeutic interventions using phosphodiesterase inhibitors to improve the placental-fetal circulation should consider fetal sex and both umbilical vein and artery reactivity.

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.

Functional and Histological Changes in Umbilical Artery and Myometrium Isolated from IUGR Complicated Pregnancies

Objective: To investigate the relaxation responses mediated by L-type Ca2+ channels and big-conductance Ca2+-activated K+ (BKCa) channels and histological changes in the human umbilical artery (HUA) and myometrium smooth muscle isolated from pregnancies complicated with intrauterine growth restriction (IUGR).Methods: The muscle reactivity and the histology of the smooth muscle of the HUA and myometrium retrieved from 14 women with IUGR and 14 controls were investigated by the isolated tissue bath and immunohistochemical method.Results: In HUA, the maximum relaxation responses and pD2 values of nifedipine and NS11021 (BKCa channel opener) were significantly increased and significant histopathological changes are observed in the IUGR group.Conclusions: The pathogenesis of IUGR might be associated with the impairment in the functional responses of L-type Ca2+ channels and BKCa channels in HUA smooth muscle. The increased staining of myometrium and UC with HIF-1α in IUGR may indicate apoptosis, histological damage, and impaired fetal growth.

Vasorelaxant effect of (E,E)-farnesol in human umbilical vein ex vivo assays

(E,E)-farnesol is a sesquiterpene acyclic alcohol produced by bacteria, protozoa, fungi, plants, and animals. The literature describes its applications in food, pharmaceutical, and cosmetic industries, and also in the pharmacological context with a vasorelaxant effect. However, its effects on human umbilical vessels remain poorly investigated. Thus, this study aims to investigate, in a new way, the vasorelaxant effect of (E,E)-farnesol in human umbilical veins (HUV) from healthy donors. Rings obtained from isolated HUV were suspended in an organ bath to record their isometric tension in different experimental sections. (E,E)-farnesol (1 μmol/L to 1 mmol/L) promoted vasorelaxant effect in venous preparations contracted by depolarization (KCl 60 mmol/L) or pharmacological agonism (5-HT 10 μmol/L), with EC50 values of 239.9 μmol/L and 424 μmol/L, respectively. In calcium-free solution, this effect was also observable. (E,E)-farnesol was able to suppress contractions evoked by CaCl2 and BaCl2 suggesting a blockade of voltage-dependent (especially L-type) calcium channels. The vasorelaxant efficacy and potency of (E,E)-farnesol were affected in the presence of tetraethylammonium (1 and 10 mmol/L), glibenclamide (10 μmol/L) and BaCl2 (1 mmol/L) indicating a possible involvement of potassium channels (BKCa, KATP and KIR) in this effect. Our data suggest that (E,E)-farnesol has a promising potential to be applicable as a vasodilator in hypertensive conditions in pregnancy that alter HUV reactivity.

Umbilical Cord Blood Gas Pairs with Near-Identical Results: Probability of Arterial or Venous Source

OBJECTIVE

 In studies of concomitant arterial-venous umbilical cord blood gases (CAV-UBGs), approximately 10% of technically valid samples have very similar pH and/or pCO2 values and were probably drawn from the same type of blood vessel. Without a way to objectively determine the source in these cases, it has been argued that most of these same-source CAV-UBGs are venous because the vein is larger and more easily sampled than the artery. This study aimed to calculate the probability of an arterial (ProbAS) or venous source (ProbVS) of same-source CAV-UBGs in the clinically and medicolegally important pH range of 6.70 to 7.25 using a statistical predictive model based on the cord blood gas values.

STUDY DESIGN

 Starting with a dataset of 56,703 CAV-UBGs, the ProbAS, ProbVS, and respective 95% confidence intervals (CIs) were calculated for the 241 sample pairs with near-identical pH, pCO2, and pO2 values and a pH of 6.70 to 7.25. Using a previously validated generalized additive model, the source was categorized as: Probable Arterial or Highly Probable Arterial if the ProbAS and CIs were >0.5 or >0.8, respectively; Probable Venous or Highly Probable Venous if the ProbVS and CIs were >0.5 or >0.8, respectively; or Indeterminant if the CIs encompassed ProbAS/VS = 0.5.

RESULTS

 A total of 39% of the same-source CAV-UBGs were Probable Arterial, 56% were Probable Venous, and 5% were Indeterminant. However, considering samples with a pH ≤7.19, 80% were Probable Arterial and 16% were Probable Venous. Considering the Highly Probable categories, the more acidemic specimens were 9 times more likely to be arterial than venous. Similarly, CAV-UBGs with pCO2 > 8.2 kPa (62 mm Hg) or pO2 ≤ 1.9 kPa (14 mm Hg) were more likely to be in the arterial rather than the venous categories.

CONCLUSION

 Same-source CAV-UBGs in the more acidemic, hypercarbic, or hypoxemic ranges are more likely to be arterial than venous.

KEY POINTS

· Umbilical cord arterial/venous gases (CAV-UBGs) with similar values are thought to be mainly venous.. · A validated statistical model was used to predict the probability an arterial or venous source.. · CAV-UBGs with very similar values and pH >  7.19 are likely venous; however, those with pH ≤ 7.19 and/or pCO2 >  8.2 kPa and/or pO2 ≤1.9 kPa are more likely arterial..

In vitro fertilization with frozen embryo transfer increased histamine-mediated contractile sensitivity via PKCβ in human umbilical vein

OBJECTIVE

In vitro fertilization-embryo transfer (IVF-ET) technologies (especially frozen ET) have been widely used, which might affect maternal and fetal health. Information regarding influence of IVF-ET on the vasoconstriction of human umbilical vein (HUV) is limited. This study determined effects of frozen ET on histamine-mediated vascular responses in HUV and related mechanisms.

METHODS AND RESULTS

HUVs were collected from frozen ET conceived pregnancy and spontaneously conceived pregnancy (control). Histamine concentration in umbilical plasma was higher in frozen ET group than the control. Histamine-mediated contractile response curve was left-shifted in the frozen ET group when comparing with the control. In isolated HUV rings, H1R showed a critical role in regulating vascular constriction, while H2R played little roles in regulating vessel tone. Iberiotoxin and 4-aminopyridine didn't significantly change histamine-mediated constriction in HUVs. Histamine-induced vasoconstrictions were significantly decreased by nifedipine, KN93, or GF109203X, while the inhibitory effects were significantly greater in the frozen ET group in comparison to the control. The constrictions by Bay K8644, phenylephrine, or PDBu were stronger in frozen ET, respectively. There was a decrease in the protein expressions of H1R and H2R, an increase in protein expressions of BK_Caα and PKCβ.

CONCLUSIONS

Histamine-induced constriction in HUV was mainly via H1R. The increased sensitivity to histamine in HUV following frozen ET cycles were linked to the enhanced PKCβ protein expression and function. The new data and findings in this study provide important insight into influences of frozen ET on fetal vessel development and potential influence in long-term.

Evaluation of the bisphenol A-induced vascular toxicity on human umbilical artery

Bisphenol A (BPA) is one of the most widely used synthetic compound in the manufacture of polycarbonate plastics and epoxy resins. Worryingly, BPA is an endocrine disrupting chemical (EDC) with an estrogenic, androgenic, or anti-androgenic activities. However, the vascular implications of BPA exposome in pregnancy is unclear. In this sense, the present work proposed to understand how BPA exposure impair the vasculature of the pregnant women. To elucidate this, ex vivo studies were performed using human umbilical arteries to explore the acute and chronic effects of BPA. The mode of action of BPA was also explored by analysing the activity (by ex vivo studies) and expression (in vitro studies) analysis of Ca²⁺ and K⁺-channels and soluble guanyl cyclase. Moreover, in silico docking simulations were performed to unveil the modes of interactions of BPA with the proteins involved in these signalling pathways. Our study showed that the exposure to BPA may modify the vasorelaxant response of HUA, interfering with NO/sGC/cGMP/PKG pathway by modulation of sGC and activation of BKCa channels. Moreover, our findings suggest that BPA can modulate the HUA reactivity, increasing the L-type Ca²⁺ Channels (LTCC) activity, a common vascular response observed in hypertensive disorders of pregnancy.

Vasodilation promoted by (E,E)-farnesol involving ion channels in human umbilical arteries

Background

(E,E)-farnesol is a sesquiterpene alcohol derived from plants and animals that exhibits pharmacological properties in the cardiovascular system. However, its effects on human umbilical vessels remain unknown.

Purpose

Thus, this study aims to characterize the vasodilatory effect of (E,E)-farnesol in human umbilical arteries (HUA).

Study design

The tissue is obtained from pregnant women over 18 years of age, normotensive, and without prepartum complications. After collected, the tissue was segmented and dissected to remove Wharton's jelly and obtain the umbilical arteries segments.

Methods

HUA segments were isolated and sectioned into rings that were subjected to isometric tension recordings in an organ bath.

Results

(E,E)-farnesol (1 μmol/L to 1 mmol/L) promoted vasodilatory effect in HUA preparations, affecting basal tone, and inhibiting the electromechanical coupling induced by KCl 60 mmol/L with greater potency (EC₅₀ 225.3 μmol/L) than the pharmacomechanical coupling induced by 5-HT 10 μmol/L (EC₅₀ 363.5 μmol/L). In the absence of extracellular calcium, pharmacomechanical coupling was also abolished, and contractions induced by CaCl₂ or BaCl₂ were attenuated by (E,E)-farnesol indicating a possible direct inhibition of L-type VOCC as a mechanism of the vasodilatory effect. The vasodilator efficacy of (E,E)-farnesol on reduction of vasocontraction induced by the presence of tetraethylammonium (1 or 10 mmol/L), 4-aminopyridine (1 mmol/L) and glibenclamide (10 μmol/L) suggesting a possible influence of different potassium channels (BK_Ca, K_V and K_ATP).

Conclusion

These results suggest that (E,E)-farnesol may be a promising pharmacological candidate for obstetric hypertensive disorders.

Comparison of relaxant effects of nifedipine and NS11021 on isolated umbilical arteries of healthy and preeclamptic pregnant women

OBJECTIVES

Potassium (K⁺) channel openers and calcium (Ca²⁺) channel blockers are currently used to treat acute severe hypertension in pregnancy. We aimed to investigate the vasorelaxant effect of NS11021, a potent and specific big-conductance Ca²⁺-activated K⁺ (BKCa) channel activator, and to compare it with the vasorelaxant effect of nifedipine on human umbilical arteries (HUAs) isolated from healthy and preeclamptic pregnants.

STUDY DESIGN

A total of 29 HUAs were isolated immediately after delivery from 14 healthy and 15 preeclamptic pregnant with severe features. The concentration-dependent relaxation responses were obtained to nifedipine and NS11021 on HUAs precontracted with endothelin-1 (ET-1) (10^-8 M) in an isolated tissue bath.

RESULTS

Both nifedipine and NS11021 caused concentration-dependent relaxation responses in HUAs from healthy and preeclamptic pregnants. While the maximum responses (Emax) and pD₂ values of nifedipine did not change significantly in both groups, the Emax and pD₂ values of NS11021 were significantly decreased in the preeclampsia group (Emax ± SEM; %75.57 ± 4.53 and %43.75 ± 14.00 and pD₂ ± SEM; 6.92 ± 0.26 and 5.24 ± 0.53 respectively, p < 0.05). In addition, the pD₂ value of NS11021 was not significantly different from that of nifedipine in the control group, but decreased significantly in the preeclampsia group (pD₂ ± SEM 7.1 ± 0.41 and 5.2 ± 0.53, p < 0.05, respectively).

CONCLUSIONS

Efficacy and potency of NS11021 decreased in HUAs from preeclamptic pregnants. Also, NS11021 is less potent than nifedipine in the preeclampsia group. BKCa channels may have a role in the pathogenesis of preeclampsia, however, further experimental studies are needed to elucidate that.

UV-B filter octylmethoxycinnamate-induced vascular endothelial disruption on rat aorta: In silico and in vitro approach

Throughout human life, an extensive and varied range of emerging environmental contaminants, called endocrine disruptors (EDCs), cause adverse health effects, including in the cardiovascular (CV) system. Cardiovascular diseases (CVD) are worryingly one of the leading causes of all mortality and mobility worldwide. The UV-B filter octylmethoxycinnamate (also designated octinoxate, or ethylhexyl methoxycinnamate (CAS number: 5466-77-3)) is an EDC widely present in all personal care products. However, to date, there are no studies evaluating the OMC-induced effects on vasculature using animal models to improve human cardiovascular health. This work analysed the effects of OMC on rat aorta vasculature and explored the modes of action implicated in these effects. Our results indicated that OMC relaxes the rat aorta by endothelium-dependent mechanisms through the signaling pathways of cyclic nucleotides and by endothelium-independent mechanisms involving inhibition of L-Type voltage-operated Ca²⁺ channels (L-Type VOCC). Overall, OMC toxicity on rat aorta may produce hypotension via vasodilation due to excessive NO release and blockade of L-Type VOCC. Moreover, the OMC-induced endothelial dysfunction may also occur by promoting the endothelial release of endothelin-1. Therefore, our findings demonstrate that exposure to OMC alters the reactivity of the rat aorta and highlight that long-term OMC exposure may increase the risk of human CV diseases.

Use of antihistamines before or during pregnancy and risk of early-onset pre-eclampsia in allergic women: a population-based cohort study

OBJECTIVE

We have previously found that allergy is a risk factor for early-onset pre-eclampsia. The aim of this study was to assess the association between pregestational maternal use of antihistamines and early-onset pre-eclampsia.

DESIGN

A population-based cohort study.

SETTING AND PARTICIPANTS

All women giving birth in Norway 2004-2016, including 692 487 pregnancies. Data from the Medical Birth Registry of Norway were linked with data from the Norwegian Prescription Database. Prescriptions of antihistamines were divided into three groups: before pregnancy (<6 months), early pregnancy (<20 weeks) and late pregnancy (20-36 weeks). ORs with 95% CIs for pre-eclampsia <34 and <37 weeks by antihistamine use were estimated by logistic regression and stratified on multiple pregnancy and parity. Predicted proportions (%) with 95% CIs were estimated.

INTERVENTIONS

Use of antihistamines in relation to pregnancy in allergic women.

MAIN OUTCOME MEASURES

Development of early-onset pre-eclampsia.

RESULTS

2997 (0.43%) and 5769 (0.83%) women had pre-eclampsia <34 and <37 weeks, respectively. Use of antihistamines before and in early pregnancy was associated with a risk of developing early-onset pre-eclampsia that was comparable to the background population (OR 1.0, 95% CI 0.8 to 1.2 and OR 0.9, 95% CI 0.7 to 1.1, respectively). Antihistamine use only in late pregnancy was not treated as exposure, but as an indicator of allergy, and was associated with an increased risk of early-onset pre-eclampsia (OR 1.8, 95% CI 1.5 to 2.2). Predicted proportions of pre-eclampsia <34 weeks were significantly lower in women using antihistamines before (0.41%, 95% CI 0.34 to 0.49) and in early pregnancy (0.37%, 95% CI 0.31 to 0.44), compared with women using antihistamines after placentation (0.69%, 95% CI 0.57 to 0.83). Results were similar for pre-eclampsia <37 weeks.

CONCLUSIONS

Antihistamine use before or during placentation was associated with reduced risk of developing early-onset pre-eclampsia in allergic women compared with women using antihistamines after placentation.

Vascular Response of Tetrabromobisphenol a in Rat Aorta: Calcium Channels Inhibition and Potassium Channels Activation

Tetrabromobisphenol A (TBBPA) is a flame retardant widely used to reduce flammability. It is an endocrine disruptor, and due to constant human exposure, some concerns have been raised regarding its impact on human health. Studies showed that TBBPA affects oxidative stress, cell proliferation and intracellular calcium levels. However, the vascular consequences of TBBPA exposure are still relatively unexplored. Hence, this work aimed to analyse TBBPA effects on rat aortic smooth muscle and its action mechanisms. Through an ex vivo approach, Wistar rat aortas were used in an organ bath to evaluate the vascular effect of TBBPA (0.01-100 μM). Additionally, TBBPA's mode of action was studied through calcium and potassium channel inhibitors. Resorting to in vitro studies, A7r5 cells were used to analyse L-Type voltage-gated calcium channel (VGCC) activity through the whole-cell configuration of the patch clamp technique, and the mRNA expression of proteins and ion channels involved in vascular contractility. The results showed vasorelaxation of rat aorta induced by TBBPA exposure, involving the inactivation of L-Type VGCC and activation of potassium channels, and the modulation of mRNA expression of L-type calcium and large-conductance calcium 1.1 and the BK_Ca 1.1 α- and β₁ -subunit channels, soluble guanylyl cyclase and protein Kinase G.

Vasorelaxant effect of monoterpene carvacrol on isolated human umbilical artery

Carvacrol is the main compound of essential oils extracted primarily from Thymus and Origanum species. Its various biological activities were confirmed: antioxidant, anti-inflammatory, antibacterial, antifungal, anti-tumour, antinematodal and vasorelaxant action. Although vasodilation mediated by carvacrol was previously described, the exact mechanism of its action has not yet been established. Hence, the aim of this study was to investigate carvacrol vasoactivity on human umbilical arteries (HUA) and different pathways involved in its mechanism of action using tissue bath methodology. Carvacrol caused a significant decrease in vascular tension of 5-HT-pre-contracted umbilical arteries, with EC50 of 442.13 ± 33.8 µM (mean ± standard error of the mean - SEM). At 300 µM, carvacrol shifted downward the 5-HT concentration-response curve with statistical significance of p < 0.001 obtained for the four highest concentrations. At concentration of 1 mM, carvacrol completely abolished BaCl2-induced contraction in Ca2+-free Krebs-Ringer bicarbonate solution (p < 0.001). Isopentenyl pyrophosphate, the antagonist of TRPV3 channel, was able to decrease the efficacy of carvacrol (p < 0.001). The vasorelaxant effect of carvacrol seems to involve the blocking of L-type of Ca2+ channels on smooth muscle cells. However, the role of TRPV3 channels in carvacrol-induced vasodilation of HUA cannot be excluded either.

UV-B Filter Octylmethoxycinnamate Is a Modulator of the Serotonin and Histamine Receptors in Human Umbilical Arteries

Every day, people use personal care products containing UV filters. Although their use initially showed a protective role, toxicity is a concern for human health as several UV filters are endocrine-disrupting chemicals (EDCs). Exposure to EDCs may induce cardiovascular diseases and can affect the health of sensitive people, such as pregnant women. Currently, the world’s most widely used UV-B filter is octylmethoxycinnamate (OMC), an EDC. However, the disruptive effects on pregnant women are little known. The present work proposed to understand how long-term exposure to OMC affects vascular homeostasis. Endothelium-denuded human umbilical artery (HUA) rings were incubated in an organ bath system. Long-term effects of exposure to OMC (0.001–50 μmol/L) were evaluated on the contractile responses of HUA to the application of the contractile agents, serotonin (5-HT) and histamine (Hist). To investigate in more detail the vascular mode of action of OMC, through which it impairs the vascular homeostasis of HUA, the activity and expression of different 5-HT and Hist-receptors involved in contractility processes were studied. Our findings pointed out an increase in the reactivity of HUA to 5-HT and Hist due to OMC exposure. These alterations in reactivity may be precursors of preeclampsia development and/or gestational hypertension.

Doppler Ultrasound of the Umbilical Artery: Clinical Application

OBJECTIVE

 To provide a survey of relevant literature on umbilical artery Doppler ultrasound use in clinical practice, technical considerations and limitations, and future perspectives.

METHODS

 Literature searches were conducted in PubMed and Medline, restricted to articles written in English. Additionally, the references of all analyzed studies were searched to obtain necessary information.

RESULTS

 The use of this technique as a routine surveillance method is only recommended for high-risk pregnancies with impaired placentation. Meta-analyses of randomized trials have established that obstetric management guided by umbilical artery Doppler findings can improve perinatal mortality and morbidity. The values of the indices of Umbilical artery Doppler decrease with advancing gestational age; however, a lack of consensus on reference ranges prevails.

CONCLUSION

 Important clinical decisions are based on the information obtained with umbilical artery Doppler ultrasound. Future efforts in research are imperative to overcome the current limitations of the technique.

PDE-Mediated Cyclic Nucleotide Compartmentation in Vascular Smooth Muscle Cells: From Basic to a Clinical Perspective

Cardiovascular diseases are important causes of mortality and morbidity worldwide. Vascular smooth muscle cells (SMCs) are major components of blood vessels and are involved in physiologic and pathophysiologic conditions. In healthy vessels, vascular SMCs contribute to vasotone and regulate blood flow by cyclic nucleotide intracellular pathways. However, vascular SMCs lose their contractile phenotype under pathological conditions and alter contractility or signalling mechanisms, including cyclic nucleotide compartmentation. In the present review, we focus on compartmentalized signaling of cyclic nucleotides in vascular smooth muscle. A deeper understanding of these mechanisms clarifies the most relevant axes for the regulation of vascular tone. Furthermore, this allows the detection of possible changes associated with pathological processes, which may be of help for the discovery of novel drugs.

Fetoplacental vasculature as a model to study human cardiovascular endocrine disruption

Increasing evidence has associated the exposure of endocrine-disrupting chemicals (EDCs) with the cardiovascular (CV) system. This exposure is particularly problematic in a sensitive window of development, pregnancy. Pregnancy exposome can affect the overall health of the pregnancy by dramatic changes in vascular physiology and endocrine activity, increasing maternal susceptibility. Moreover, fetoplacental vascular function is generally altered, increasing the risk of developing pregnancy complications (including cardiovascular diseases, CVD) and predisposing the foetus to adverse health risks later in life. Thus, our review summarizes the existing literature on exposures to EDCs during pregnancy and adverse maternal health outcomes, focusing on the human placenta, vein, and umbilical artery associated with pregnancy complications. The purpose of this review is to highlight the role of fetoplacental vasculature as a model for the study of human cardiovascular endocrine disruption. Therefore, we emphasize that the placenta, together with the umbilical arteries and veins, allows a better characterization of the pregnant woman's exposome. Consequently, it contributes to the protection of the mother and foetus against CV disorders in life.

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.

The Serotonin-Immune Axis in Preeclampsia

PURPOSE OF REVIEW

To review the literature and detail the potential immune mechanisms by which hyperserotonemia may drive pro-inflammation in preeclampsia and to provide insights into potential avenues for therapeutic discovery.

RECENT FINDINGS

Preeclampsia is a severe hypertensive complication of pregnancy associated with significant maternal and fetal risk. Though it lacks any effective treatment aside from delivery of the fetus and placenta, recent work suggests that targeting serotonin systems may be one effective therapeutic avenue. Serotonin dysregulation underlies multiple domains of physiologic dysfunction in preeclampsia, including vascular hyporeactivity and excess platelet aggregation. Broadly, serotonin is increased across maternal and placental domains, driven by decreased catabolism and increased availability of tryptophan precursor. Pro-inflammation, another hallmark of the disease, may drive hyperserotonemia in preeclampsia. Interactions between immunologic dysfunction and hyperserotonemia in preeclampsia depend on multiple mechanisms, which we discuss in the present review. These include altered immune cell, kynurenine pathway metabolism, and aberrant cytokine production mechanisms, which we detail. Future work may leverage animal and in vitro models to reveal serotonin targets in the context of preeclampsia's immune biology, and ultimately to mitigate vascular and platelet dysfunction in the disease. Hyperserotonemia in preeclampsia drives pro-inflammation via metabolic, immune cell, and cytokine-based mechanisms. These immune mechanisms may be targeted to treat vascular and platelet endophenotypes in preeclampsia.

UV-B filter octylmethoxycinnamate impaired the main vasorelaxant mechanism of human umbilical artery

Personal care products (PCPs) are a group of diverse substances widely used daily for health, beauty, and cleanliness. More than 90% of all PCPs contain the UV-B filter octylmethoxycinnamate (OMC) as a protective function, however, their safety has recently been questioned. The purpose of the present work was to understand how the long-term exposure of UV-filter OMC, used daily by pregnant women, disrupts their vascular homeostasis, altering vascular responses of proteins and channels involved in contractile processes. The long-term effects of 24 h of exposure to OMC (1, 10, and 50 μmol/L) were evaluated on contractile responses of human umbilical arteries (HUA) to serotonin and potassium chloride. Since OMC altered vascular homeostasis of arteries, its vascular mode of action was explored in more detail through the analysis of the activity of cGMP and Ca²⁺-channels, two pathways involved in their relaxation and contraction, respectively. Our findings showed that long-term exposure of UV-filter OMC impaired the main vasorelaxant mechanism of HUA, once OMC altered the vasorelaxant response pattern of sodium nitroprusside and nifedipine. Results also showed that long-term exposure to OMC induced a decreased vasorelaxation response on HUA due to an interference with the NO/sGC/cGMP/PKG pathway. Moreover, OMC seems to modulate the L-type Ca²⁺ channels, the BKCa 1.1 α-subunit channels, and the PKG. Overall, since OMC compromises the vascular homeostasis of pregnant women it can be an inductor of pregnancy hypertensive disorders.

Extracellular matrix-mediated remodeling and mechanotransduction in large vessels during development and disease

The vascular extracellular matrix (ECM) is synthesized and secreted during embryogenesis and facilitates the growth and remodeling of large vessels. Proper interactions between the ECM and vascular cells are pivotal for building the vasculature required for postnatal dynamic circulation. The ECM serves as a structural component by maintaining the integrity of the vessel wall while also regulating intercellular signaling, which involves cytokines and growth factors. The major ECM component in large vessels is elastic fibers, which include elastin and microfibrils. Elastin is predominantly synthesized by vascular smooth muscle cells (SMCs) and uses microfibrils as a scaffold to lay down and assemble cross-linked elastin. The absence of elastin causes developmental defects that result in the subendothelial proliferation of SMCs and inward remodeling of the vessel wall. Notably, elastic fiber formation is attenuated in the ductus arteriosus and umbilical arteries. These two vessels function during embryogenesis and close after birth via cellular proliferation, migration, and matrix accumulation. In dynamic postnatal mechano-environments, the elastic fibers in large vessels also serve an essential role in proper signal transduction as a component of elastin-contractile units. Disrupted mechanotransduction in SMCs leads to pathological conditions such as aortic aneurysms that exhibit outward remodeling. This review discusses the importance of the ECM-mainly the elastic fiber matrix-in large vessels during developmental remodeling and under pathological conditions. By dissecting the role of the ECM in large vessels, we aim to provide insights into the role of ECM-mediated signal transduction that can provide a basis for seeking new targets for intervention in vascular diseases.

A Robust Bioassay of the Human Bradykinin B2 Receptor that Extends Molecular and Cellular Studies: The Isolated Umbilical Vein

Bradykinin (BK) has various physiological and pathological roles. Medicinal chemistry efforts targeted toward the widely expressed BK B₂ receptor (B₂R), a G-protein-coupled receptor, were primarily aimed at developing antagonists. The only B₂R antagonist in clinical use is the peptide icatibant, approved to abort attacks of hereditary angioedema. However, the anti-inflammatory applications of B₂R antagonists are potentially wider. Furthermore, the B₂R antagonists notoriously exhibit species-specific pharmacological profiles. Classical smooth muscle contractility assays are exploited over a time scale of several hours and support determining potency, competitiveness, residual agonist activity, specificity, and reversibility of pharmacological agents. The contractility assay based on the isolated human umbilical vein, expressing B₂R at physiological density, was introduced when investigating the first non-peptide B₂R antagonist (WIN 64338). Small ligand molecules characterized using the assay include the exquisitely potent competitive antagonist, Pharvaris Compound 3 or the partial agonist Fujisawa Compound 47a. The umbilical vein assay is also useful to verify pharmacologic properties of special peptide B₂R ligands, such as the carboxypeptidase-activated latent agonists and fluorescent probes. Furthermore, the proposed agonist effect of tissue kallikrein on the B₂R has been disproved using the vein. This assay stands in between cellular and molecular pharmacology and in vivo studies.

UV-B Filter Octylmethoxycinnamate Alters the Vascular Contractility Patterns in Pregnant Women with Hypothyroidism

Increasing evidence relating the exposure and/or bioaccumulation of endocrine-disrupting compounds (EDCs) with cardiovascular system are arising. Octylmethoxycinnamate (OMC) is the most widely used UV-B filter and as EDC interacts with TH receptors. However, their effects on thyroid diseases during pregnancy remain unknown. The purpose of this work was to assess the short- and long-term effects of OMC on arterial tonus of pregnant women with hypothyroidism. To elucidate this, human umbilical artery (HUA) rings without endothelium were used to explore the vascular effects of OMC by arterial and cellular experiments. The binding energy and the modes of interaction of the OMC into the active center of the TSHR and THRα were analyzed by molecular docking studies. Our results indicated that OMC altered the contractility patterns of HUA contracted with serotonin, histamine and KCl, possibly due to an interference with serotonin and histamine receptors or an involvement of the Ca²⁺ channels. The molecular docking analysis show that OMC compete with T₃ for the binding center of THRα. Taken together, these findings pointed out to alterations in HUA reactivity as result of OMC-exposure, which may be involved in the development and increased risk of cardiovascular diseases.

Angiogenesis in the Avian Embryo Chorioallantoic Membrane: A Perspective on Research Trends and a Case Study on Toxicant Vascular Effects

The chorioallantoic membrane (CAM) of the avian embryo is an intrinsically interesting gas exchange and osmoregulation organ. Beyond study by comparative biologists, however, the CAM vascular bed has been the focus of translational studies by cardiovascular life scientists interested in the CAM as a model for probing angiogenesis, heart development, and physiological functions. In this perspective article, we consider areas of cardiovascular research that have benefited from studies of the CAM, including the themes of investigation of the CAM's hemodynamic influence on heart and central vessel development, use of the CAM as a model vascular bed for studying angiogenesis, and the CAM as an assay tool. A case study on CAM vascularization effects of very low doses of crude oil as a toxicant is also presented that embraces some of these themes, showing the induction of subtle changes in the pattern of the CAM vasculature growth that are not readily observed by standard vascular assessment methodologies. We conclude by raising several questions in the area of CAM research, including the following: (1) Do changes in patterns of CAM growth, as opposed to absolute CAM growth, have biological significance?; (2) How does the relative amount of CAM vascularization compared to the embryo per se change during development?; and (3) Is the CAM actually representative of the mammalian systemic vascular beds that it is presumed to model?

Clinical Importance of the Human Umbilical Artery Potassium Channels

Potassium (K⁺) channels are usually predominant in the membranes of vascular smooth muscle cells (SMCs). These channels play an important role in regulating the membrane potential and vessel contractility-a role that depends on the vascular bed. Thus, the activity of K⁺ channels represents one of the main mechanisms regulating the vascular tone in physiological and pathophysiological conditions. Briefly, the activation of K⁺ channels in SMC leads to hyperpolarization and vasorelaxation, while its inhibition induces depolarization and consequent vascular contraction. Currently, there are four different types of K⁺ channels described in SMCs: voltage-dependent K⁺ (K_V) channels, calcium-activated K⁺ (K_Ca) channels, inward rectifier K⁺ (Kir) channels, and 2-pore domain K⁺ (K_2P) channels. Due to the fundamental role of K⁺ channels in excitable cells, these channels are promising therapeutic targets in clinical practice. Therefore, this review discusses the basic properties of the various types of K⁺ channels, including structure, cellular mechanisms that regulate their activity, and new advances in the development of activators and blockers of these channels. The vascular functions of these channels will be discussed with a focus on vascular SMCs of the human umbilical artery. Then, the clinical importance of K⁺ channels in the treatment and prevention of cardiovascular diseases during pregnancy, such as gestational hypertension and preeclampsia, will be explored.

Relaxant Effect of Monoterpene (-)-Carveol on Isolated Human Umbilical Cord Arteries and the Involvement of Ion Channels

Carveol is a monoterpene present in the structure of many plant products. It has a variety of biological activities: antioxidant, anticancer and vasorelaxation. However, studies investigating the effect of monoterpenoids on human vessels have not yet been described. Thus, the present study aimed to characterize the effect of (−)-carveol on human umbilical arteries (HUAs). HUA ring preparations were isolated and subjected to isometric tension recordings of umbilical artery smooth muscle contractions. (−)-Carveol exhibited a significant vasorelaxant effect on KCl and 5-HT-induced contractions, obtaining EC₅₀ values of 344.25 ± 8.4 and 175.82 ± 4.05 µM, respectively. The participation of calcium channels in the relaxation produced by (−)-carveol was analyzed using vessels pre-incubated with (−)-carveol (2000 µM) in a calcium-free medium, where the induction of contractions was abolished. The vasorelaxant effect of (−)-carveol on HUAs was reduced by tetraethylammonium (TEA), which increased the (−)-carveol EC₅₀ to 484.87 ± 6.55 µM. The present study revealed that (−)-carveol possesses a vasorelaxant activity in HUAs, which was dependent on the opening of calcium and potassium channels. These results pave the way for further studies involving the use of monoterpenoids for the vasodilatation of HUAs. These molecules have the potential to treat diseases such as pre-eclampsia, which is characterized by resistance in umbilical arteries.

Vascular mechanisms of testosterone: The non-genomic point of view

Testosterone (T) is the predominant endogenous androgen in the bloodstream. At the vascular level, T presents genomic and non-genomic effects, and both effects may overlap. The genomic actions assume that androgens can freely cross the plasma membrane of target cells and bind to nuclear androgen receptors, inducing gene transcription and protein synthesis. The non-genomic effects have a more rapid onset and may be related to the interaction with protein/receptor/ion channels of the plasma membrane. The key T effect at the vascular level is vasorelaxation, which is primarily due to its rapid effect. Thus, the main purpose of this review is to discuss the T non-genomic effects at the vascular level and the molecular pathways involved in its vasodilator effect observed in in vivo and in vitro studies. In this sense, the nuclear receptor activation, the influence of vascular endothelium and the activation or inhibition of ion channels (potassium and calcium channels, respectively) will be reviewed regarding all the data that corroborated or not. Moreover, this review also provides a brief update on the association of T with the risk factors for cardiovascular diseases, namely metabolic syndrome, type 2 diabetes mellitus, obesity, atherosclerosis, dyslipidaemia, and hypertension. In summary, in this paper we consider the non-genomic vascular mode of action of androgen in physiological conditions and the main risk factors for cardiovascular diseases.

Androgen Effects on the Adrenergic System of the Vascular, Airway, and Cardiac Myocytes and Their Relevance in Pathological Processes

INTRODUCTION

Androgen signaling comprises nongenomic and genomic pathways. Nongenomic actions are not related to the binding of the androgen receptor (AR) and occur rapidly. The genomic effects implicate the binding to a cytosolic AR, leading to protein synthesis. Both events are independent of each other. Genomic effects have been associated with different pathologies such as vascular ischemia, hypertension, asthma, and cardiovascular diseases. Catecholamines play a crucial role in regulating vascular smooth muscle (VSM), airway smooth muscle (ASM), and cardiac muscle (CM) function and tone.

OBJECTIVE

The aim of this review is an updated analysis of the role of androgens in the adrenergic system of vascular, airway, and cardiac myocytes. Body. Testosterone (T) favors vasoconstriction, and its concentration fluctuation during life stages can affect the vascular tone and might contribute to the development of hypertension. In the VSM, T increases α1-adrenergic receptors (α ₁-ARs) and decreases adenylyl cyclase expression, favoring high blood pressure and hypertension. Androgens have also been associated with asthma. During puberty, girls are more susceptible to present asthma symptoms than boys because of the increment in the plasmatic concentrations of T in young men. In the ASM, β ₂-ARs are responsible for the bronchodilator effect, and T augments the expression of β ₂-ARs evoking an increase in the relaxing response to salbutamol. The levels of T are also associated with an increment in atherosclerosis and cardiovascular risk. In the CM, activation of α _1A-ARs and β ₂-ARs increases the ionotropic activity, leading to the development of contraction, and T upregulates the expression of both receptors and improves the myocardial performance.

CONCLUSIONS

Androgens play an essential role in the adrenergic system of vascular, airway, and cardiac myocytes, favoring either a state of health or disease. While the use of androgens as a therapeutic tool for treating asthma symptoms or heart disease is proposed, the vascular system is warmly affected.

UV-B Filter Octylmethoxycinnamate Induces Vasorelaxation by Ca2+ Channel Inhibition and Guanylyl Cyclase Activation in Human Umbilical Arteries

Ultraviolet (UV) filters are chemicals widely used in personal care products (PCPs). Due to their effect as endocrine disruptor compounds (EDCs), the toxicity of UV filters is a current concern for human health. EDC exposure may be correlated to cardiovascular diseases (CVD), but to our knowledge, no studies assessed the UV filters effects as human EDCs at the vascular level. Octylmethoxycinnamate (OMC) is the world's most widely used UV-B filter, present in more than 90% of PCPs. Due to its demonstrated multiple hormonal activities in animal models, this substance is also suspected to be a human EDC. The purpose of this study was to assess the rapid/short-term effects of OMC on arterial tonus and analyse its mode of action (MOA). Using human umbilical arteries, the endocrine effects of OMC were evaluated in in vitro (cellular and organ) experiments by planar cell surface area (PCSA) and organ bath, respectively. Our data show that OMC induces a rapid/short-term smooth muscle relaxation acting through an endothelium-independent MOA, which seems to be shared with oestrogens, involving an activation of soluble guanylyl cyclase (sGC) that increases the cyclic guanosine monophosphate (cGMP) intracellular levels and an inhibition of L-type voltage-operated Ca²⁺ channels (L-Type VOCC).