Human Umbilical Vessels Research Articles

Epigenetic regulation by hypoxia, N-acetylcysteine and hydrogen sulphide of the fetal vasculature in growth restricted offspring: A study in humans and chicken embryos.

Fetal growth restriction (FGR) is a common outcome in human suboptimal gestation and is related to prenatal origins of cardiovascular dysfunction in offspring. Despite this, therapy of human translational potential has not been identified. Using human umbilical and placental vessels and the chicken embryo model, we combined cellular, molecular, and functional studies to determine whether N-acetylcysteine (NAC) and hydrogen sulphide (H2S) protect cardiovascular function in growth-restricted unborn offspring. In human umbilical and placental arteries from control or FGR pregnancy and in vessels from near-term chicken embryos incubated under normoxic or hypoxic conditions, we determined the expression of the H2S gene CTH (i.e. cystathionine γ-lyase) (via quantitative PCR), the production of H2S (enzymatic activity), the DNA methylation profile (pyrosequencing) and vasodilator reactivity (wire myography) in the presence and absence of NAC treatment. The data show that FGR and hypoxia increased CTH expression in the embryonic/fetal vasculature in both species. NAC treatment increased aortic CTH expression and H2S production and enhanced third-order femoral artery dilator responses to the H2S donor sodium hydrosulphide in chicken embryos. NAC treatment also restored impaired endothelial relaxation in human third-to-fourth order chorionic arteries from FGR pregnancies and in third-order femoral arteries from hypoxic chicken embryos. This NAC-induced protection against endothelial dysfunction in hypoxic chicken embryos was mediated via nitric oxide independent mechanisms. Both developmental hypoxia and NAC promoted vascular changes in CTH DNA and NOS3methylation patterns in chicken embryos. Combined, therefore, the data support that the effects of NAC and H2S offer a powerful mechanism of human translational potential against fetal cardiovascular dysfunction in complicated pregnancy. KEY POINTS: Gestation complicated by chronic fetal hypoxia and fetal growth restriction (FGR) increases a prenatal origin of cardiovascular disease in offspring, increasing interest in antenatal therapy to prevent against a fetal origin of cardiovascular dysfunction. We investigated the effects between N-acetylcysteine (NAC) and hydrogen sulphide (H2S) in the vasculature in FGR human pregnancy and in chronically hypoxic chicken embryos. Combining cellular, molecular, epigenetic and functional studies, we show that the vascular expression and synthesis of H2S is enhanced in hypoxic and FGR unborn offspring in both species and this acts to protect their vasculature. Therefore, the NAC/H2S pathway offers a powerful therapeutic mechanism of human translational potential against fetal cardiovascular dysfunction in complicated pregnancy.

ABCG2-Expressing Clonal Repopulating Endothelial Cells Serve to Form and Maintain Blood Vessels.

Most organs are maintained lifelong by resident stem/progenitor cells. During development and regeneration, lineage-specific stem/progenitor cells can contribute to the growth or maintenance of different organs, whereas fully differentiated mature cells have less regenerative potential. However, it is unclear whether vascular endothelial cells (ECs) are also replenished by stem/progenitor cells with EC-repopulating potential residing in blood vessels. It has been reported recently that some EC populations possess higher clonal proliferative potential and vessel-forming capacity compared with mature ECs. Nevertheless, a marker to identify vascular clonal repopulating ECs (CRECs) in murine and human individuals is lacking, and, hence, the mechanism for the proliferative, self-renewal, and vessel-forming potential of CRECs is elusive. We analyzed colony-forming, self-renewal, and vessel-forming potential of ABCG2 (ATP binding cassette subfamily G member 2)-expressing ECs in human umbilical vessels. To study the contribution of Abcg2-expressing ECs to vessel development and regeneration, we developed Abcg2CreErt2;ROSA TdTomato mice and performed lineage tracing during mouse development and during tissue regeneration after myocardial infarction injury. RNA sequencing and chromatin methylation chromatin immunoprecipitation followed by sequencing were conducted to study the gene regulation in Abcg2-expressing ECs. In human and mouse vessels, ECs with higher ABCG2 expression (ABCECs) possess higher clonal proliferative potential and in vivo vessel-forming potential compared with mature ECs. These cells could clonally contribute to vessel formation in primary and secondary recipients after transplantation. These features of ABCECs meet the criteria of CRECs. Results from lineage tracing experiments confirm that Abcg2-expressing CRECs (AbcCRECs) contribute to arteries, veins, and capillaries in cardiac tissue development and vascular tissue regeneration after myocardial infarction. Transcriptome and epigenetic analyses reveal that a gene expression signature involved in angiogenesis and vessel development is enriched in AbcCRECs. In addition, various angiogenic genes, such as Notch2 and Hey2, are bivalently modified by trimethylation at the 4th and 27th lysine residue of histone H3 (H3K4me3 and H3K27me3) in AbcCRECs. These results are the first to establish that a single prospective marker identifies CRECs in mice and human individuals, which holds promise to provide new cell therapies for repair of damaged vessels in patients with endothelial dysfunction.

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.

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. PurposeThus, this study aims to characterize the vasodilatory effect of (E,E)-farnesol in human umbilical arteries (HUA). Study designThe 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. MethodsHUA 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 (BKCa, KV and KATP). ConclusionThese results suggest that (E,E)-farnesol may be a promising pharmacological candidate for obstetric hypertensive disorders.

Release of 6-nitrodopamine from human popliteal artery and vein

6-Nitrodopamine (6-ND) is a novel catecholamine that is released from human umbilical cord vessels, and it causes vascular relaxation by acting as a dopamine D2-receptor antagonist. Here it was investigated whether human peripheral vessels obtained from patients who have undergone surgery for leg amputation release 6-ND, and its action in these tissues. Popliteal artery and vein strips present basal release of 6-ND, as measured by liquid chromatography coupled to tandem mass spectrometry. The release was significantly reduced when the tissues were pre-treated with the nitric oxide synthase inhibitor L-NAME (100 μM), or when the endothelium was mechanically removed. In U-46619 (3 nM) pre-contracted rings, 6-ND induced concentration-dependent relaxations (pEC50 8.18 ± 0.05 and 8.40 ± 0.08, in artery and vein rings, respectively). The concentration-dependent relaxations induced by 6-ND were unaffected in tissues pre-treated with L-NAME, but significantly reduced in tissues where the endothelium has been mechanically removed. In U-46619 (3 nM) pre-contracted rings, the selective dopamine D2 receptor antagonist L-741,626 also caused concentration-dependent relaxations (pEC50 8.92 ± 0.22 and 8.79 ± 0.19, in artery and vein rings, respectively). The concentration-dependent relaxations induced by L-741,626 were unaffected in tissues pre-treated with L-NAME, but significantly reduced in tissues where the endothelium has been mechanically removed. This is the first demonstration that 6-nitrodopamine is released from human peripheral artery and vein rings. The results also indicate that endothelium-derived dopamine is a major contractile agent in the popliteal artery and vein, and that selective dopamine D2-receptor antagonists such as 6-ND, may have therapeutic potential in the treatment of human peripheral vascular diseases.

Specific dilation pattern in placental circulation and the NO/sGC role in preeclampsia placental vessels.

Endothelial functions in controlling blood flow in placental circulation are still unclear. The present study compares vascular dilations between placental circulation and other vessels, as well as between normal and preeclampsia placental vessels. Placental, umbilical, and other vessels (cerebral and mesenteric arteries) were collected from humans, sheep, and rats. Vasodilation was tested by JZ101 and DMT. Q-PCR, Western blot, and Elisa were used for molecular experiments. Endothelium-dependent/derived vasodilators, including acetylcholine, bradykinin, prostacyclin, and histamine, mediated no or minimal dilation in placental circulation, which was different from that in other vessels in sheep and rats. There were lower mRNA expressions of muscarinic receptors, histamine receptors, bradykinin receptor 2, endothelial nitric oxide synthesis (eNOS), and less nitric oxide (NO) in human umbilical vessels when compared with placental vessels. Exogenous NO donors (sodium nitroprusside, SNP) and soluble guanylate cyclase (sGC) activators (Bay41-2272) decreased the baseline of vessel tone in placental circulation in humans, sheep, and rats, but not in other arteries. The sGC inhibitor ODQ suppressed the reduced baseline caused by the SNP. The decreased baseline by SNP or Bay41-2272 was higher in placental vessels than in umbilical vessels, suggesting that the role of NO/sGC is more important in the placenta. NO concentrations in preeclampsia placental vessels were lower than those in control, while no significant change was found in umbilical plasma between the two groups. eNOS expression was similar between normal and preeclampsia placental vessels, but phosphorylated eNOS levels were significantly lower in preeclampsia. Following serotonin, SNP or Bay41-2272-mediated dilations were weaker in preeclampsia placental vessels. The decreased amplitude of SNP- or Bay41-2272 at baseline was smaller in preeclampsia. The decreased amplitudes of ODQ + SNP were comparable between the two groups. Despite higher beta sGC expression, sGC activity in the preeclampsia placenta was lower. This study demonstrated that receptor-mediated endothelium-dependent dilation in placental circulation was significantly weaker than other vessels in various species. The results, showed firstly, that exogenous NO played a role in regulating the baseline tone of placental circulation via sGC. Lower NO production and decreased NO/sGC could be one of the reasons for preeclampsia. The findings contribute to understanding specific features of placental circulation and provide information about preeclampsia in placental vessels.

The preeclampsia condition alters external potassium-evoked contraction of human umbilical vessels

IntroductionPre-eclampsia (PE) is a disease of high incidence in parturients, that adversely affects both mother and fetus. Although PE prevalence is high, there are few studies on literature describing its etiology or its mechanism of action. Thus, the aim of this study was to elucidate PE-induced alterations of contractile reactivity in umbilical vessels. MethodSegments of human umbilical artery (HUA) and human umbilical vein (HUV) from neonates of normotensive or PE parturients were obtained and contractile responses measured with a myograph. The segments were allowed to stabilize (2 h) under 1.0, 2.0 and 3.0 g force (gf) at pre-stimulation and, then, were stimulated with high isotonic K+ concentrations ([K+]o; 10–120 mM). ResultsAll preparations responded to increases in isotonic K+ concentrations. In HUA and HUV of neonates of normotensive parturients, and in HUV of neonates of PE parturients, the contraction saturated at nearly 50 mM [K+]o, while in HUA of neonates of PE parturients, saturation occurred at 30 mM [K+]o. Additionally, several differences between contractile responses of HUA and HUV from neonates of normotensive parturients and those from neonates of parturients with PE were observed. PE alters the contractile response of the HUA and HUV to increased [K+]o, and its contractile modulation by the pre-stimulus basal tension. Moreover, in HUA of PE, reactivity is decreased for 2.0 and 3.0 gf basal tensions and increased for 1.0 gf; in the HUV of PE condition, it is increased for all basal tensions. DiscussionIn conclusion, PE promotes several alterations in HUA and HUV contractile reactivity, vessels in which important circulatory alterations are known to occur.

Proteomics and bioinformatics analysis of cardiovascular related proteins in offspring exposed to gestational diabetes mellitus.

IntroductionPrevious studies have demonstrated that exposed to the initial suboptimal intrauterine environment of gestational diabetes mellitus (GDM) may increase risk of cardiovascular disease in adulthood.MethodsIn order to investigate the underlying mechanisms involved in the increased risk of cardiovascular diseases (CVDs) in the offspring of GDM, we applied a high-throughput proteomics approach to compare the proteomic expression profile of human umbilical vessels of normal and GDM offspring.ResultsA total of significantly different 100 proteins were identified in umbilical vessels from GDM group compared with normal controls, among which 31 proteins were up-regulated, while 69 proteins were down-regulated. Differentially expressed proteins (DEPs) are validated using Western blotting analysis. The analysis of these differently expressed proteins (DEPs) related diseases and functions results, performed by Ingenuity Pathway Analysis (IPA) software. Based on “Diseases and Disorders” analysis, 17 proteins (ACTA2, ADAR, CBFB, DDAH1, FBN1, FGA, FGB, FGG, GLS, GSTM1, HBB, PGM3, PPP1R13L, S100A8, SLC12A4, TPP2, VCAN) were described to be associated with CVD, especially in Anemia, Thrombus and Myocardial infarction. Functional analysis indicated that DEPs involved in many cardiovascular functions, especially in “vasoconstriction of blood vessel” (related DEPs: ACTA2, DDAH1, FBN1, FGA, FGB, and FGG). Upstream regulator analyses of DEPs identifies STAT3 as inhibitor of ACTA2, FGA, FGB, and FGG.ConclusionThe results of this study indicate that intrauterine hyperglycemia is associated with an elevated risk of cardiovascular risk in the offspring.

Nerve regeneration conduit from inverted human umbilical cord vessel in the treatment of proper palmar digital nerve sections

Treatment of digital nerve injuries, particularly in case of a gap, is challenging. Recovery of finger sensitivity is often incomplete and can impair personal and occupational activity. The need for better nerve regeneration has given rise to alternative treatments such as nerve conduits. This study aimed to evaluate the safety and efficacy of a conduit of freeze-dried inverted human umbilical cord vessel for regeneration in digital nerve section. Twenty-three patients with a mean nerve gap of 6.11 mm (range 2–30 mm and static 2-point discrimination (s2PD) > 15 mm underwent surgical repair of digital nerve section using a nerve regeneration conduit. The primary endpoint was recovery of sensitivity after conduit implantation. Secondary endpoints comprised progression of pain, functional symptoms, pressure threshold, hand-specific symptoms and disabilities, and restored innervation. Mean follow-up was 10.1 ± 4.1 months (range 1–14 months). Sensitivity recovered progressively in the months following implantation. There was a mean decrease of 8.54 mm in s2PD between baseline and last follow-up (p < 0.001). Complete innervation recovered in 83.3% of cases at last follow-up. Pressure threshold and hand-related quality of life improved significantly and symptoms due to nerve sectioning (pain, cold intolerance, hypoesthesia, hyperesthesia) resolved almost completely. There were no safety issues related to the nerve conduit. These results indicate that freeze-dried inverted human umbilical vessels can be a safe and effective option as conduit for digital nerve regeneration.

Release of 6-nitrodopamine modulates vascular reactivity of Pantherophis guttatus aortic rings

6-Nitrodopamine (6-ND) is a novel catecholamine that is released from human umbilical cord vessels and Chelonoidis carbonaria aortic rings. The synthesis/release of 6-ND is inhibited by either pre-incubation of the vessels with the nitric oxide (NO) synthase inhibitor L-NAME or by mechanical removal of the endothelium. 6-ND causes powerful vasorelaxation, acting as a potent and selective dopamine D2-like receptor antagonist.Basal release of 6-ND from Panterophis guttatus endothelium intact and denuded aortic rings was quantified by LC-MS/MS. In order to evaluate the interaction of 6-ND with other catecholamines, aortic rings were suspended vertically between two metal hooks in 10-mL organ baths containing Krebs-Henseleit's solution and attached to isometric transducers.Endothelium intact aortic rings presented basal release of 6-ND, which was significantly reduced by previous incubation with L-NAME (100 μM). In endothelin-1 (3 nM) pre-contracted endothelium intact aortic rings, 6-ND (10pM-1 μM) and the dopamine D2-receptor antagonist L-761,626 (10 pM–1 μM) induced concentration-dependent relaxations, which were not affected by incubation with L-NAME but greatly reduced in endothelium-removed aortic rings.6-ND (0.1–1 μM) produced significant rightward shifts of the concentration-response curves to dopamine in L-NAME pre-treated endothelium-intact (pA2 7.01) rings. Contractions induced by noradrenaline and adrenaline were not affected by pre-incubation with 6-ND (1 μM). The EFS-induced contractions of L-NAME pre-treated endothelium-intact aortic rings were significantly inhibited by incubation with 6-ND (1 μM).The results indicate that 6-ND released from Pantherophis guttatus aortic rings is coupled to NO release and represents a new mechanism by which NO can modulate vascular reactivity independently of cGMP production.

6-Nitrodopamine is an endogenous mediator of rat isolated epididymal vas deferens contractions induced by electric-field stimulation

6-nitrodopamine (6-ND) is released from human umbilical cord vessels and modulates vascular reactivity by acting as a dopamine antagonist. Here we investigate whether 6-ND is released by the rat isolated vas deferens and its effect on this tissue. Dopamine, noradrenaline, adrenaline and 6-ND levels were quantified in rat isolated vas deferens by LC-MS-MS. Electric-field stimulation (EFS) and concentration-response curves to 6-ND, noradrenaline, dopamine and adrenaline were performed in the absence and in the presence (30 min) of L-NAME, SCH-23390, haloperidol, PG-01037, sonepiprazole, desipramine, clomipramine, amitriptyline, cyclobenzaprine, carbamazepine, maprotiline, paroxetine, oxcarbazepine and ketanserin in the rat isolated epididymal vas deferens (RIEVD).Basal releases of 6-ND and noradrenaline were detected from the rat isolated vas deferens. 6-ND release was reduced by tissue incubation with L-NAME and from the vas deferens obtained from L-NAME-treated rats.SCH-23390 caused leftward shifts on concentration-response curves to 6-ND without affecting dopamine- or EFS-induced RIEVD contractions. Haloperidol, PG-01037 and sonepiprazole caused significant rightward shifts on concentration-response curves to dopamine but had no effect on either the 6-ND or EFS-induced RIEVD contractions.The tricyclic compounds desipramine, clomipramine, amitriptyline, cyclobenzaprine and carbamazepine induced rightward shifts on 6-ND concentration-response curve but did not reduce the noradrenaline, dopamine and adrenaline contractile responses. They also reduced the EFS-induced RIEVD contractions in control but not in tissues obtained from L-NAME-treated animals. Maprotiline, oxcarbazepine, paroxetine and ketanserin had no effect in either 6-ND or EFS-induced RIEVD contractions.Thus, 6-ND modulates RIEVD contractility, and desipramine, clomipramine, amitriptyline, cyclobenzaprine and carbamazepine act as selective 6-ND receptor antagonists.

PD62-12 6-NITRODOPAMINE IS RELEASED BY RAT ISOLATED VAS DEFERENS AND MODULATES ITS CONTRACTILITY

INTRODUCTION AND OBJECTIVE:6-nitrodopamine (6-ND) is released by human umbilical cord vessels and acts as a dopamine D2-receptor antagonist in this tissue in vitro. Here it was investigated whether...

6-Nitrodopamine is released by human umbilical cord vessels and modulates vascular reactivity

AimsHuman umbilical cord vessels (HUCV) release dopamine and nitric oxide (NO). This study aims to verify whether HUCV release nitrocatecholamines such as 6-nitrodopamine (6-ND). Main methodsLiquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) was used to identify 6-ND release from HUCV rings incubated in Krebs-Henseileit's solution. Vascular reactivity of HUCV rings was tested (with and without endothelium integrity) by suspension of the rings in an organ bath under isometric tension and application of 6-ND and other known mediators. Key findingsLC-MS/MS revealed a basal release of 6-ND from endothelium intact from both human umbilical artery (HUA) and vein (HUV). The endothelium intact release was inhibited by the pre-treatment with NO synthesis inhibitor L-NAME (100 μM). In contrast to dopamine, noradrenaline and adrenaline, 6-ND did not contract HUCV, even in presence of L-NAME or ODQ. 6-ND (10 μM) produced a rightward shift of the concentration-response curves to dopamine (pA2: 5.96 in HUA and 5.72 in HUV). Contractions induced by noradrenaline and adrenaline were not affected by pre-incubation with 6-ND (10 μM).In U-46619 (10 nM) pre-contracted endothelium intact tissues, 6-ND and the dopamine D2-receptor antagonist haloperidol induced concentration-dependent relaxations of HUA and HUV. Incubation with the dopamine D1-receptor antagonist SCH-23390 (10 nM) abolished relaxation induced by fenoldopam but did not affect those induced by 6-ND. Significance6-ND is released by HUCV and acts as a selective dopamine D2-receptor antagonist in this tissue. This represents a novel mechanism by which NO may modulate vascular reactivity independently of cGMP production.

Leptin prevents U46619, and angiotensin II elicited contractions in isolated human umbilical vessels

Leptin prevents U46619, and angiotensin II elicited contractions in isolated human umbilical vessels

Endothelium-derived dopamine modulates EFS-induced contractions of human umbilical vessels.

Electrical field stimulation (EFS) induces contractions of both snake aorta and human umbilical cord vessels (HUCV) which were dependent on the presence of the endothelium. This study aimed to establish the nature of the mediator(s) responsible for EFS‐induced contractions in HUCV. Rings with or without endothelium from human umbilical artery (HUA) or vein (HUV) were mounted in organ bath chambers containing oxygenated, heated Krebs‐Henseleit's solution. Basal release of dopamine (DA), noradrenaline, and adrenaline was measured by LC‐MS‐MS. Cumulative concentration‐response curves were performed with dopamine in the absence and in the presence of L‐NAME or of dopamine antagonists. EFS studies were performed in the presence and absence of L‐NAME, the α‐adrenergic blockers prazosin and idazoxan, and the dopamine antagonists SCH‐23390 and haloperidol. Tyrosine hydroxylase (TH) and dopa‐decarboxylase (DDC) were studied by immunohistochemistry and fluorescence in situ hybridizations. Basal release of dopamine requires an intact endothelium in both HUA and HUV. TH and DDC are present only in the endothelium of both HUA and HUV as determined by immunohistochemistry. Dopamine induced contractions in HUA only in the presence of L‐NAME. Dopamine‐induced contractions in HUV were strongly potentiated by L‐NAME. The EFS‐induced contractions in both HUA and HUV were potentiated by L‐NAME and inhibited by the D2‐like receptor antagonist haloperidol. The α‐adrenergic antagonists prazosin and idazoxan and the D1‐like receptor antagonist SCH‐23390 had no effect on the EFS‐induced contractions of HUA and HUV. Endothelium‐derived dopamine is a major modulator of HUCV reactivity in vitro.

Human Umbilical Cord (HUC) Vessels: A Novel Substitute for Arterial Bypass Grafting

Human Umbilical Cord (HUC) Vessels: A Novel Substitute for Arterial Bypass Grafting

Electrical field stimulation induces endothelium-dependent contraction of human umbilical cord vessels

Electrical field stimulation (EFS) has been used for decades in classical pharmacological preparations in order to characterize the mediators released by neural endings involved in smooth muscle contraction or relaxation. Since most of the human umbilical cord has no innervation, EFS has never been used in this preparation. This study aimed to investigate the effect of EFS on vascular responsiveness from human umbilical cord. Segments of the human umbilical cord were obtained from normotensive parturients and the human umbilical artery (HUA) and the human umbilical vein (HUV) were isolated and mounted in organ bath chambers. Electrical field stimulation-induced contractions in both HUA (2.35 ± 1.31 mN and 3.77 ± 2.31 mN for 8 Hz and 16 Hz respectively, n = 24) and HUV (3.81 ± 2.54 mN and 6.26 ± 4.51 mN for 8 Hz and 16 Hz respectively, n = 25). The addition of tetrodotoxin (1 μM) did not alter the EFS-induced contractions in both tissues (n = 5). Pre-incubation with atropine (10 and 100 μM), glibenclamide (10 μM) and indomethacin (10 μM) did not affect the EFS-induced contractions in both tissues. The contractions of both vessels were significantly reduced by pre-incubation of the tissues with phentolamine (10 and 100 μM). The endothelium removal almost abolished the EFS- induced contractions in both vessels (n = 5). In sandwich preparation, donor tissue (with endothelium) released a factor (s) that promoted contraction of the recipient tissue (endothelium removal) in both HUA and HUV (n = 5, respectively). Our findings indicate a potential role of endothelium-derived catecholamines in modulating HUA and HUV reactivities.

Cyclic nucleotide-dependent relaxation in human umbilical vessels.

Umbilical vessels have a low sensitivity to dilate, and this property is speculated to have physiological implications. We aimed to investigate the different relaxing responses of human umbilical arteries (HUAs) and veins (HUVs) to agonists acting through the cAMP and cGMP pathways. Vascular rings were suspended in organ baths for isometric force measurement. Following precontraction with the thromboxane prostanoid (TP) receptor agonist U44069, concentration-response curves to the nitric oxide (NO) donor sodium nitroprusside (SNP), the soluble guanylate cyclase (sGC) stimulator BAY 41-2272, the adenylate cyclase (AC) activator forskolin, the β-adrenergic receptor agonists isoproterenol (ADRB1), salmeterol (ADRB2), and BRL37344 (ADRB3), and the phosphodiesterase (PDE) inhibitors milrinone (PDE3), rolipram (PDE4), and sildenafil (PDE5) were performed. None of the tested drugs induced a relaxation higher than 30% of the U44069-induced tone. Rings from HUAs and HUVs showed a similar relaxation to forskolin, SNP, PDE inhibitors, and ADRB agonists. BAY 41-2272 was significantly more efficient in relaxing veins than arteries. ADRB agonists evoked weak relaxations (< 20%), which were impaired in endothelium-removed vessels or in the presence of the NO synthase inhibitor L-NAME, sGC inhibitor ODQ. PKA and PKG inhibitors impaired ADBR1-mediated relaxation but did not affect ADRB2-mediated relaxation. ADRB3-mediated relaxation was impaired by PKG inhibition in HUAs and by PKA inhibition in HUVs. Although HUA and HUV rings were relaxed by BRL37344, immunohistochemistry and RT-qPCR analysis showed that, compared to ADRB1 and ADRB2, ADRB3 receptors are weakly or not expressed in umbilical vessels. In conclusion, our study confirmed the low relaxing capacity of HUAs and HUVs from term infants. ADRB-induced relaxation is partially mediated by endothelium-derived NO pathway in human umbilical vessels.

Human Umbilical Vessels: Choosing the Optimal Decellularization Method

There is an increasing demand of small-diameter vascular grafts for treatment of circulatory pathologies. Decellularization offers the possibility of using human blood vessels as scaffolds to create vascular grafts. Umbilical vessels have great potential because of their availability and morphological characteristics. Various decellularization techniques have been used in umbilical vessels, but consensus on which is the most appropriate has not yet been reached. The objective of this review is to analyze the morphological and biomechanical characteristics of decellularized human umbilical arteries and veins with different techniques. Evidence indicates that the umbilical vessels are a viable option to develop small-diameter vascular grafts. Detergents are the agents most often used and with most evidence. However, further studies are needed to accurately analyze the components of the extracellular matrix and biomechanical characteristics, as well as the capacity for recellularization and in vivo functionality.

Characterization of the hemodynamic wall shear stresses in human umbilical vessels from normal and intrauterine growth restricted pregnancies.

Significant reductions in blood flow and umbilical diameters were reported in pregnancies affected by intrauterine growth restriction (IUGR) from placental insufficiency. However, it is not known if IUGR umbilical blood vessels experience different hemodynamic wall shear stresses (WSS) compared to normal umbilical vessels. As WSS is known to influence vasoactivity and vascular growth and remodeling, which can regulate flow rates, it is important to study this parameter. In this study, we aim to characterize umbilical vascular WSS environment in normal and IUGR pregnancies, and evaluate correlation between WSS and vascular diameter, and gestational age. Twenty-two normal and 21 IUGR pregnancies were assessed via ultrasound between the 27th and 39th gestational week. IUGR was defined as estimated fetal weight and/or abdominal circumference below the 10th centile, with no improvement during the remainder of the pregnancy. Vascular diameter was determined by 3D ultrasound scans and image segmentation. Umbilical artery (UA) WSS was computed via computational flow simulations, while umbilical vein (UV) WSS was computed via the Poiseuille equation. Univariate multiple regression analysis was used to test for the differences between normal and IUGR cohort. UV volumetric flow rate, UA and UV diameters were significantly lower in IUGR fetuses, but flow velocities and WSS trends in UA and UV were very similar between normal and IUGR groups. In both groups, UV WSS showed a significant negative correlation with diameter, but UA WSS had no correlation with diameter, suggesting a constancy of WSS environment and the existence of WSS homeostasis in UA, but not in UV. Despite having reduced flow rate and vascular sizes, IUGR UAs had hemodynamic mechanical stress environments and trends that were similar to those in normal pregnancies. This suggested that endothelial dysfunction or abnormal mechanosensing was unlikely to be the cause of small vessels in IUGR umbilical cords.