Vasodilator Activity Research Articles

Gut Microbiome and Kidney Disease: Reconciling Optimism and Skepticism.

Gut Microbiome and Kidney Disease: Reconciling Optimism and Skepticism.

Design, synthesis, and biological evaluation of novel NO-releasing 4-chromanone derivatives as potential vasodilator agents.

The nitric oxide/cyclic guanosine monophosphate (NO/cGMP) signaling pathway is an effective mechanism involved in the treatment of hypertension. In our search for potential antihypertensive agents, a series of novel NO-donor derivatives of the 4-chromanone skeleton were designed and synthesized by coupling furoxans or nitrooxy NO-donor moieties. All derivatives showed enhanced nitric oxide releasing capacity and vasodilator activity with EC50 values ranging from 0.0215 μM to 1.46 μM, obviously superior to those of precursor 3. These biological evaluations indicated that all compounds displayed an important vasorelaxant effect, and several compounds (9c, 14b, 14c, 14d) presented good vasodilator activity, with 14c being the best. Furthermore, molecular modeling studies revealed that compound 14c occupied the pocket well with the phosphodiesterase 5 domain in a favorable conformation. In conclusion, we observed that these novel compounds can act as structural templates for the design and subsequent development of new vasodilators and antihypertensive drugs.

Lyso-DGTS Lipid Derivatives Enhance PON1 Activities and Prevent Oxidation of LDL: A Structure-Activity Relationship Study.

Paraoxonase 1 (PON1) plays a role in regulating reverse cholesterol transport and has antioxidative, anti-inflammatory, antiapoptotic, vasodilative, and antithrombotic activities. Scientists are currently focused on the modulation of PON1 expression using different pharmacological, nutritional, and lifestyle approaches. We previously isolated a novel active compound from Nannochloropsis microalgae—lyso-diacylglyceryltrimethylhomoserine (lyso-DGTS)—which increased PON1 activity, HDL-cholesterol efflux, and endothelial nitric oxide release. Here, to explore this important lipid moiety’s effect on PON1 activities, we examined the effect of synthesized lipid derivatives and endogenous analogs of lyso-DGTS on PON1 lactonase and arylesterase activities and LDL oxidation using structure–activity relationship (SAR) methods. Six lipids significantly elevated recombinant PON1 (rePON1) lactonase activity in a dose-dependent manner, and four lipids significantly increased rePON1 arylesterase activity. Using tryptophan fluorescence-quenching assay and a molecular docking method, lipid–PON1 interactions were characterized. An inverse correlation was obtained between the lactonase activity of PON1 and the docking energy of the lipid–PON1 complex. Furthermore, five of the lipids increased the LDL oxidation lag time and inhibited its propagation. Our findings suggest a beneficial effect of lyso-DGTS or lyso-DGTS derivatives through increased PON1 activity and prevention of LDL oxidation.

Synthesis and Vasorelaxant Activity of Nitrate-Coumarin Derivatives.

Due to the need for new chemical entities for cardiovascular diseases, we have synthesized a new series of nitrate-coumarins and evaluated their vasorelaxant activity in contraction-relaxation studies using rat aorta rings precontracted with phenylephrine or by depolarization with a high concentration of potassium chloride. Four of the new compounds were able to relax smooth vascular muscle with a similar profile and potency to glyceryl trinitrate (IC50 =12.73 nM) and sodium nitroprusside (IC50 =4.32 nM). Coumarin-7-yl-methyl nitrate (4), the best compound within the series, was able to relax smooth vascular muscle in the low nanomolar range (IC50 =1.92 nM). The mechanisms of action have been explored, being the activation of sGC and the opening of K+ channels involved. Our studies indicate that the new nitrate derivatives are reversible and not deleterious for aortic rings, suggesting that these compounds have a potential interest for the development of new and highly efficient vasodilator drugs.

Study on the vasodilatory activity of lotus leaf extract and its representative substance nuciferine on thoracic aorta in rats.

Lotus (Nelumbo nucifera) leaves are widely used for both edible and medicinal applications. For its further utilization, we studied the vasodilatory activity of lotus leaf extract for the first time. In this study, we obtained the extracts using different ratios of water and ethanol, which was followed by polarity-dependent extraction. We found that the CH2Cl2 layer exhibited better vasodilatory activity (EC50 = 1.21 ± 0.10 μg/ml). HPLC and ESI-HRMS analysis of the CH2Cl2 layer using the standard product as a control revealed that nuciferine (Emax = 97.95 ± 0.76%, EC50 = 0.36 ± 0.02 μM) was the main component in this layer. Further research revealed that nuciferine exerts a multi-target synergistic effect to promote vasodilation, via the NO signaling pathway, K+ channel, Ca2+ channel, intracellular Ca2+ release, α and β receptors, etc. Nuciferine exhibits good vasodilatory activity, and it exhibits the potential to be utilized as a lead compound.

Carvedilol reduces the risk of decompensation and mortality in patients with compensated cirrhosis in a competing-risk meta-analysis.

Whether non-selective β-blockers can prevent decompensation of cirrhosis warrants clarification. Carvedilol might be particularly effective since its intrinsic vasodilatory activity may ameliorate hepatic vascular resistance, a major mechanism of portal hypertension in early cirrhosis. We assessed whether carvedilol may prevent decompensation and improve survival in patients with compensated cirrhosis and clinically significant portal hypertension (CSPH). By systematic review we identified randomized-controlled trials (RCTs) comparing carvedilol vs. control therapy (no-active treatment or endoscopic variceal ligation [EVL]) in patients with cirrhosis and CSPH without previous bleeding. We performed a competing-risk time-to-event meta-analysis using individual patient data (IPD) obtained from principal investigators of RCTs. Only compensated patients were included. Primary outcomes were prevention of decompensation (liver transplantation and death were competing events) and death (liver transplantation was a competing event). Models were adjusted using propensity scores for baseline covariates with the inverse probability of treatment weighting (IPTW) approach. Among 125 full-text studies evaluated, 4 RCTs were eligible. The 4 provided IPD and were included, comprising 352 patients with compensated cirrhosis, 181 treated with carvedilol and 171 controls (79 received EVL and 92 placebo). Baseline characteristics were similar between groups. Standardized differences were <10% by IPTW. The risk of developing decompensation of cirrhosis was lower with carvedilol than in controls (subdistribution hazard ratio [SHR] 0.506; 95% CI 0.289-0.887; p= 0.017; I2= 0.0%, Q-statistic-p= 0.880), mainly due to a reduced risk of ascites (SHR 0.491; 95% CI 0.247-0.974; p= 0.042; I2= 0.0%, Q-statistic-p= 0.384). The risk of death was also lower with carvedilol (SHR 0.417; 95% CI 0.194-0.896; p= 0.025; I2= 0.0%, Q-statistic-p= 0.989). Long-term carvedilol therapy reduced decompensation of cirrhosis and significantly improved survival in compensated patients with CSPH. This suggests that screening patients with compensated cirrhosis for CSPH to enable the prompt initiation of carvedilol could improve outcomes. CRD42019144786. The transition from compensated cirrhosis to decompensated cirrhosis is associated with markedly reduced life expectancy. Therefore, preventing decompensation in patients with compensated cirrhosis would be associated with greatly improved patient outcomes. There has been controversy regarding the use of non-selective β-blockers (portal pressure-lowering medications) in patients with cirrhosis and elevated portal blood pressure (portal hypertension). Herein, using a competing-risk meta-analysis to optimize sample size and properly investigate cirrhosis as a multistate disease and outcomes as time-dependent events, we show that carvedilol (a non-selective β-blocker) is associated with a reduced risk of decompensating events and improved survival in patients with cirrhosis and portal hypertension.

Treprostinil Supplementation Ameliorates Hepatic Ischemia Reperfusion Injury and Regulates Expression of Hepatic Drug Transporters: An Isolated Perfused Rat Liver (IPRL) Study

PurposeIR injury is an unavoidable consequence in deceased donor liver transplantation. Cold preservation and warm reperfusion may change the expression and function of drug transporters in the liver due to vasoconstriction, infiltration of neutrophils and release of cytokines. We hypothesize that vasodilation, anti-platelet aggregation and proinflammatory downregulation activities of treprostinil will diminish the IR injury and its associated effects.MethodsLivers obtained from male SD rats (n = 20) were divided into 1) Control, 2) IR, 3) Treprostinil-1 (preservation only), and 4) Treprostinil-2 (preservation and reperfusion) groups. Control livers were procured and immediately reperfused. Livers in the other groups underwent preservation for 24 h and were reperfused. All the livers were perfused using an Isolated Perfused Rat Liver (IPRL) system. Periodic perfusate, cumulative bile samples and liver tissue at the end of perfusion were collected. Liver injury markers, bile flow rates, m-RNA levels for uptake and efflux transporters (qRT-PCR) were measured.ResultsCold preservation and warm reperfusion significantly increased the release of AST and ALT in untreated livers. Treprostinil supplementation substantially reduced liver injury. Bile flow rate was significantly improved in treprostinil-2 group. m-RNA levels of Slc10a1, Slc22a1, and Slc22a7 in liver were increased and m-RNA levels of Mdr1a were decreased by IR. Treprostinil treatment increased Abcb11 and Abcg2 m-RNA levels and maintained Slc22a1m-RNA similar to control livers.ConclusionsTreprostinil treatment significantly reduced liver injury. IR injury changed expression of both uptake and efflux transporters in rat livers. Treprostinil significantly altered the IR injury mediated changes in m-RNA expression of transporters.

Abstract P002: Mechanism Of Mesenteric Artery Vasodilation And Blood Pressure Regulation By Statins

Purpose: Statins are the world’s most prescribed drugs with a wide variety of cholesterol-dependent and -independent cardiovascular effects. Pre-clinical and clinical data suggest that statins lower blood pressure (BP) in some patients but have no effect in others. However, the underlying mechanism for such differences remain unclear. By studying the direct vascular effects of therapeutically relevant concentrations of statins in resistance mesenteric arteries from normotensive Sprague Dawley (SD) rats and Spontaneously Hypertensive (SHR) rats, we sought to determine the mechanism of differential BP regulation by statins. Methods: Pressurized arterial myography, phosphodiesterase (PDE) activity assay, ELISA-based cGMP measurement, blood pressure measurement with tail-cuff. Results: Our pressure myography data revealed that statins induce rapid vasodilation in resistance mesenteric arteries. Endothelium denudation, inhibition of endothelial nitric oxide (NO) synthase (eNOS) with L-NNA, smooth muscle cell (SMC) guanylyl cyclase (sGC) inhibition with ODQ, or the inhibition of protein kinase G (PKG) with KT5823 each abolished statin-evoked vasodilation, demonstrating a critical role of endothelium and NO signaling in this process. However, contrary to previous reports, mevalonate application had no effect on vasodilation. Statins selectively inhibited PDE1A in SMCs, elevated [cGMP] i , which could potentiate NO-GC-cGMP-PKG signaling, leading to vasodilation. Statin-evoked vasodilation is attenuated in SHR rat mesenteric arteries that have reduced eNOS expression and impaired NO signaling. Consistent with the vasodilatory action, acute statin treatment lowered systolic and diastolic BP in healthy SD rats. In contrast, acute statin treatment failed to lower systemic BP in SHR rats with reduced eNOS expression. Conclusion: Statins are endothelium-dependent vasodilator, and selective inhibitor of PDE1A in resistance mesenteric arteries. Intact endothelial function and NO production are essential for statin-induced vasodilation and the reduction of BP. Our study could provide explanation to the anti-hypertensive and BP neutral effects of statins.

Potential biomedical applications of Araucaria araucana as an antispasmodic, bronchodilator, vasodilator, and antiemetic: Involvement of calcium channels

Ethnopharmacological relevanceSince pre-Columbian era, the resin of Araucaria araucana tree has been used traditionally for the treatment of ulcers and wounds. Araucaria species have also been used to treat inflammation, respiratory problems, viral infections, ulcers, and rheumatoid, cardiovascular, and neurological disorders. Aims and objectiveDue to its popular use, the authors aimed to scrutinize the potential of this plant as an antispasmodic and an antiemetic agent. Furthermore broncho- and vasodilatory effects of this plant was explored to rationalize its folkloric uses. Materials and methodsAraucaria araucana crude extract (Aa.Cr) was evaluated in isolated preparations of rabbit jejunum, trachea, aorta, and atria to investigate the antispasmodic, bronchodilator, and vasodilator effects. The potential mechanistic approaches were compared with the standard drug ‘verapamil’. The antiemetic activity was determined and compared with the standard drug ‘domperidone’ via chick emesis model. ResultsAa.Cr dose-dependently relaxed both spontaneous and K+-induced contractions in the isolated jejunum preparations of rabbits. In concentration–response curves of calcium (Ca++), Aa.Cr also triggered the rightward shift like verapamil. Applying carbachol and phenylephrine (1 μM) and K+ (80 mM) to the isolated tracheal and aortic tissue preparation, respectively, resulted in broncho- and vasodilatory activities, respectively which may be due to the inhibition of Ca++ channels. Aa.Cr inhibited atrial force and spontaneous contractions in the rabbit's right atria. Aa.Cr exhibited significant antiemetic activity (P < 0.001 vs. saline) in dose-dependent (50–150 mg/kg) manner like domperidone. In silico molecular docking was performed to investigate the biological targets of purified components of Aa.Cr which revealed that cadinol dominantly targets β2 receptors to cause bronchodilation, however, eudesmin binds non-specifically to all the selected targets, while secoisolariciresinol mediated high hydrogen bonding with muscarinic receptors (M1 and M3) and Ca++ channels, thus shows the suggested mechanistic pathways of targeted activities. ConclusionsThe results of this study indicates that Aa.Cr may exhibit antispasmodic activity, bronchodilation, and vasodilation by inhibiting voltage-dependent Ca++ channels and release of subcellular calcium. This explains its folkloric use in hypertension, bronchospasms, gastrointestinal spasms, and emesis.

Are Thermoregulatory Sweating and Active Vasodilation in Skin Controlled by Separate Nerves During Passive Heat Stress in Persons With Spinal Cord Injury?

Sudomotor responses (SR) and active vasodilation (AVD) are the primary means of heat dissipation during passive heat stress (PHS). It is unknown if they are controlled by a single or separate set of nerves. Older qualitative studies suggest that persons with spinal cord injury (SCI) have discordant areas of sweating and vasodilation. To test the hypothesis that neural control of SR and AVD is through separate nerves by measuring SR and vasodilation in persons with SCI to determine if these areas are concordant or discordant. Nine persons with tetraplegia, 13 with paraplegia, and nine able-bodied controls underwent PHS (core temperature rise 1°C) twice. Initially, the starch iodine test measured SR post-PHS in skin surface areas surrounding the level of injury. Subsequently, laser Doppler imagery scans measured vasodilation pre- and post-PHS in areas with and without SR. Percent change in red blood cell (RBC) flux was compared in areas with and without SR. Persons with tetraplegia were anhidrotic on all areas; however, the same areas demonstrated minimal RBC flux change significantly less than equivalent able-bodied skin surface areas. In persons with paraplegia, areas of intact SR correlated with areas of RBC flux change quantitatively comparable to able-bodied persons. In anhidrotic areas, RBC flux change was significantly less than areas with SR and likely resulted from non-AVD mechanisms. In persons with SCI under PHS, areas with intact SR and AVD are concordant, suggesting these two aspects of thermoregulation are controlled by a single set of nerves.

Hinokitiol produces vasodilation in aortae from normal and angiotensin II- induced hypertensive rats via endothelial-dependent and independent pathways

Hinokitiol is a natural bioactive compound with numerous pharmacological properties. Here, we aimed to examine hinokitiol's effects on vascular relaxation. Cumulative relaxation responses to hinokitiol were assessed in isolated aortae from normotensive and angiotensin II-induced hypertensive rats in the presence and absence of selective inhibitors. Hinokitiol produced vasodilation of phenylephrine preconstricted aortae using both normotensive and hypertensive rats. In normotensive rats, hinokitiol's vasodilation was reduced by endothelial denudation and nitric oxide synthase (NOS), guanylate cyclase, and cyclooxygenase inhibition. Also, hinokitiol vasodilation was attenuated by β-receptors, adenylate cyclase, Ca2+-activated K+ channels and hyperpolarization inhibition. Moreover, hinokitiol exhibited a blocking activity on Ca2+ mobilization through voltage dependent Ca2+ channels (VDCC). However, its effect was not changed by muscarinic receptor and Sarc-K+ ATP channels blocking but was enhanced by blocking voltage-dependent K+ channels. However, in angiotensin II-induced hypertension, hinokitiol vasodilating activity was attenuated by NOS inhibition and it blocked Ca2+ mobilization through VDCC, while its vasodilation was partially attenuated by Sarc-K+ ATP channels blocking. However, the vasodilating effect of hinokitiol was not attenuated by either cyclooxygenase, β-receptor, Ca2+-activated K+ channels, or voltage-dependent potassium channels inhibition, but was enhanced by blocking hyperpolarization. Hinokitiol's vasodilating effect in normotensive and hypertensive vessels is mediated through both endothelium-dependent and endothelium-independent mechanisms.

A Single Dosage of l-Arginine Oral Supplementation Induced Post-Aerobic Exercise Hypotension in Hypertensive Patients

Lowering of peripheral vascular resistance is one of the primary processes involved in blood pressure decrease. Nitric oxide plays a significant role in this process and the availability of l-arginine is a crucial element in nitric oxide biosynthesis. Oral l-arginine supplementation may therefore be a potentiating element in post-exercise hypotension, mediated by its vasodilator action. Thus, the purpose of this study was to investigate if a single dose of l-arginine oral supplementation might impact the post-aerobic exercise blood pressure responses in treated hypertensive individuals. A double-blind, randomized, placebo-controlled crossover trial was conducted. The sample included male (4) and female (6) subjects [62 ± 10 years]. The participants were randomized to ingest one sachet containing 8 grams of l-arginine or placebo (corn starch) dissolved in water (100 ml). The substances were self-administered 120 min before the experimental or control session. The exercise was conducted on a treadmill and consisted of: a 5 min warm-up (50-65% HRreserve); 40 min of running/walking at 60-70% HRreserve; and a 5 min progressive cooldown. After the exercise sessions, blood pressure was measured every 10 min for 60 min. The l-arginine supplementation arm led to significant post-exercise systolic hypotension (mean post-exercise) in relation to rest period (117 ± 12 vs 125 ± 15 mmHg - p = 0.004 [l-arginine] and 121 ± 11 vs 125 ± 15 - p = 0.341 [placebo]). In addition, a systolic net effect of −6.9 ± 3.6 mmHg [p = 0.046] was identified for the mean post-exercise values. Therefore, this study showed that a single dosage of l-arginine oral supplementation induced post-aerobic exercise hypotension in hypertensive patients.

Recent Advances in Hydrogel-Mediated Nitric Oxide Delivery Systems Targeted for Wound Healing Applications.

Despite the noticeable evolution in wound treatment over the centuries, a functional material that promotes correct and swift wound healing is important, considering the relative weight of chronic wounds in healthcare. Difficult to heal in a fashionable time, chronic wounds are more prone to infections and complications thereof. Nitric oxide (NO) has been explored for wound healing applications due to its appealing properties, which in the wound healing context include vasodilation, angiogenesis promotion, cell proliferation, and antimicrobial activity. NO delivery is facilitated by molecules that release NO when prompted, whose stability is ensured using carriers. Hydrogels, popular materials for wound dressings, have been studied as scaffolds for NO storage and delivery, showing promising results such as enhanced wound healing, controlled and sustained NO release, and bactericidal properties. Systems reported so far regarding NO delivery by hydrogels are reviewed.

Salvianolic acid A from Danhong Injection induces vasorelaxation by Regulating L-type calcium channel in isolated mouse arteries

Ethnopharmacological relevanceDanhong injection (DHI), which is a Chinese clinical prescription consists of Radix et Rhizoma Salviae Miltiorrhizae (Salvia miltiorrhiza Bge., Labiatae, Danshen in Chinese) and Flos Carthami (Carthamus tinctorius L., Compositae, Honghua in Chinese)(Plant names have been checked with http://www.theplantlist.org on March 1st, 2022), has been mainly used in the clinical therapy of cardiovascular diseases, including hypertension in China for many years. Aim of the studyCardiovascular diseases (CVDs) are the major causes of death all around the world. Due to the various stimulation, a series of vasoconstrictor substances are secreted to regulate the vasoconstriction function and then change blood pressure. The representative substances leading to abnormal vasoconstriction include renin-angiotensin system, endothelin, vasopressin and adrenaline, which act on the corresponding receptors on vascular smooth muscle to constrict blood vessels. Finally, blood pressure increases, followed by a series of cardiovascular diseases, including hypertension. However, little is known about Danhong injection’s specific vasodilating mechanisms and active substances. The aims of the study were to determine the vasodilating substances of Danhong injection and explain its molecular mechanism of vasodilation. Materials and methodsThe effects of DHI and its active components on vascular tension were measured by myograph system in the aortic or mesenteric rings of mice. Based on this, the pharmacodynamic substances were analyzed and effective molecules were found. Combined with multiple types of vascular myograph experiments and network pharmacological analysis, the molecular pathway was preliminarily determined. With molecular biology experiments, it was verified that the relevant mechanisms were closely related to calcium-mediated vasoconstriction in smooth muscle cells. ResultsDHI could relax endothelium-removed aortic rings pre-constricted with PE and 3 possible active vasodilator substances, including salvianolic acid A, salvianolic acid B and danshensu, were screened out by network pharmacology and vascular myograph experiments, among which the effects of salvianolic acid A were dominant. Meanwhile, salvianolic acid A could dilate mesenteric artery in a pressure-dependent manner. Interestingly, salvianolic acid A could still relax the vascular rings under the stimulation of KCl and Bayk8644, two agonists of L-type calcium channel. By contrast, inhibitors of Kir, Kv, Katp and BKCa channels did not block the effect of salvianolic acid A on vasodilation. Salvianolic acid A alleviated Ca2+ transient, referring to changes of intracellular calcium, induced by PE, Bayk8644 and high K+ in the VSMCs. Salvianolic acid A could partially restore the vasodilation function of vascular smooth muscle damaged by AngII and ET-1 induced hypertension situation. ConclusionsOur results indicate that salvianolic acid A is the major vasodilator substance in DHI and the vasorelaxation pharmacology mechanism involved in inhibiting the L-type calcium channel signaling in smooth muscle cell. Hence, there are potential therapeutic effects of taking salvianolic acid A preparation which may be beneficial to protect cardiovascular system and reduce blood pressure.

New paeonol derivative C302 reduces hypertension in spontaneously hypertensive rats through endothelium-dependent and endothelium-independent vasodilation

Hypertension is a major risk factor for cardiovascular disease and Chinese herb monomers could provide new structural skeletons for anti-hypertension new drug development. Paeonol is a Chinese herbal monomer extracted from Cortex moutan, exhibited some anti-hypertensive activity. The study focused on the structural optimization of paeonol to provide promising lead compounds for anti-hypertension new drug development. Herein, twelve new paeonol derivatives (PD) were designed and synthesized and their vasodilation activity was evaluated by in vitro vasodilation drug screening platform based on Myograph. Its anti-hypertension activity, PD-C302 (2-hydroxy-4-methoxyvalerophenone) as a representative with the optimal vasodilation activity, was determined by its response to blood pressure in spontaneously hypertensive rats (SHR) in vivo. Moreover, its molecular mechanism was probed by the vasodilation activity of rat superior mesenteric artery rings with or without endothelium pre-contracted by potassium chloride (KCl) or phenylephrine hydrochloride (PE). It was indicated that PD-C302 significantly reduced the blood pressure in SHR, which would involve in PD-C302-induced vasodilation. Furthermore, endothelium-dependent pathways and endothelium-independent pathways both contributed importantly to PD-C302-induced vasodilation at low concentration of PD-C302. Endothelium-independent pathways (vascular smooth muscle cell-mediated vasodilation), were mainly responsible for the PD-C302-induced vasodilation at high concentration of PD-C302, which involved in opening multiple K+ channels to restrain Ca2+ channels, and then triggered vasodilation to reduce blood pressure. PD-C302 has a simple structure and favorable anti-hypertensive activity in vivo, which could be a promising lead compound for anti-hypertension new drug development.

Reversing thromboxane A2 receptor activity from calcium to cAMP signaling by shifting Gαq to Gαs covalently linked to the receptor

The conversion of a G-protein coupling receptor (GPCR) signaling from one G-protein to another could be a novel concept for drug designs. Thromboxane A2 (TXA2) receptor (TP) plays a key role in mediating platelet aggregation and thrombosis through its binding to TXA2 and coupling with Gαq-calcium signaling. To alter TP coupling from Gαq to Gαs, which mediates the opposite anti-platelet aggregation and vasodilation activities, we first created a recombinant single-chain (SC) TP-Gαq complex (SC-TP-Gαq) in which the Gαq N-terminus is covalently linked to the TP C-terminus. The SC-TP-Gαq expressed on HEK293 cells could perform identical functions of wild-type TP binding to agonist and activating Gαq triggering Ca2+ signal. The results were further confirmed by expressing the SC-TP-Gαq on CRISPR-edited Gαq-knocked-out HEK293 cells. A step further, by replacing Gαq using Gαs for SC-TP-Gαq, a second recombinant SC-TP-Gαs was created and expressed on wild type and CRISPR-edited Gαs-knocked-out HEK293 cells. Upon the binding of the same TXA2 agonist to the cells expressing SC-TP-Gαs, cAMP signaling was observed. The results have provided strong evidence that covalently linking TP with different Gα could control cell signaling. This study has opened a door to developing a method to redirect TP signaling from thrombotic calcium to anti-thrombotic cAMP, and apply it to that of other GPCRs.

P163 BOTALLO ARTERIAL DUCT SURGICALLY TREATED IN URGENCY

Abstract The Botallo arterial duct connects the pulmonary artery and the aorta during fetal life; after birth there is a progressive fall in pulmonary resistance mediated by the increase in oxygen concentration and the decrease in prostaglandins with a vasodilating action. In these physiological conditions, spontaneous closure of the duct is observed within the first 48–72 hours of life. In the preterm infant the patency of the Botallo duct is very frequent due to the peculiar anatomical and physiological characteristics of the preterm infant. The incidence of PDA is higher the lower the birth weight and gestational age are. We report a case of Manuel, a baby born at 32 weeks of gestational age from elective CT due to transverse presentation with difficulty in extraction and anhydrosis. 37–year–old mother hospitalized for reduction of amniotic fluid (AFI 85 index) with no apparent rupture of the membranes, for which she began a cycle of glucocorticoids 12mg twice a day. At birth, the weight of the child was 1,780 g, length 42 cm, skull circumference 28 cm, absence of valid respiratory activity, bradycardia (78 bpm) APGAR index of 4. At 5 ‘of life he was intubated with a 3 Fi rush tube fixed to 8 cm from the buccal rim with neopuff with PIP 20 cmH2O, PEEP 5 cmH2O, FiO2 0.40, transferred to the NICU, placed in the incubator, connected to the ventilator and ventilated with A/C mode with PIP 23 cmH2O, PEEP 5 cmH2O, FiO2 0, 40 –&amp;gt; 0.60, given surfactant alfa 200 mg/kg. Anemic, plasma and red blood cells were administered multiple times; infectious disease tests (aerobic–anaerobic haemocolutre, umbilical culture, culture of OT tubes, BAL, ear and throat swabs) were negative. After 3 days, systolic heart murmur appeared 2–3/6 radiated to the axilla. The echocardium showed the persistence of the Duct of Botallo, with a mosaic jet in the pulmonary artery and a “growing” ductal flow pattern. He started treatment with indomethacin 0.2 mg/kg every 12 hours x 3 doses, but on echocardiographic control the picture remained unchanged. At 16 days of age, the newborn was transferred to the Bambin Gesù in Rome and underwent cardiac surgery via the left posterolateral thoracotomy to close the arterial duct with a Weck clip. The post–operative course was regular. Manuel was discharged 2.5 months after birth in good general conditions, good growth–weight, with a weight of 2460 g.

White Wine-Induced Endothelium-Dependent Vasorelaxation in Sprague-Dawley Rats.

The vasodilatory activity and polyphenolic content of commercially available white wine is low compared to red wines. This study assessed the vasodilator potential of white wines produced by four different fermentation processes: (1) white wine produced by the standard procedure; (2) grapes left to macerate completely for 30 days; (3) grapes left to macerate up to half of unfermented sugar; and (4) wine produced by cooling the must. All tested wine samples were analyzed for their phenolic content, antioxidant capacity, and ethanol content. Vasodilation was examined in the norepinephrine pre-contracted isolated rat aortas of male Sprague-Dawley rats randomly exposed to cumulative concentrations (0.1‰ to 8‰ final dilutions in organ baths) of each of the tested wine samples with or without quercetin and/or gallic acid supplementation, in the absence/presence of NOS inhibitor L-NAME. Standard procedure and the procedure involving must cooling gives wine with lower phenolic content, antioxidant capacity, and lower vasodilator potential, respectively. L-NAME inhibited vasodilation to all wine samples. Quercetin with or without gallic acid supplementation restored vasodilation. Results show that vasodilation to white wine is NO-dependent and suggest the possibility of increasing the antioxidant capacity and vasodilatory potential of white wine using different production procedures, depending on quercetin content.

A physiologically relevant role for NO stored in vascular smooth muscle cells: A novel theory of vascular NO signaling

S-nitrosothiols (SNO), dinitrosyl iron complexes (DNIC), and nitroglycerine (NTG) dilate vessels via activation of soluble guanylyl cyclase (sGC) in vascular smooth muscle cells. Although these compounds are often considered to be nitric oxide (NO) donors, attempts to ascribe their vasodilatory activity to NO-donating properties have failed. Even more puzzling, many of these compounds have vasodilatory potency comparable to or even greater than that of NO itself, despite low membrane permeability. This raises the question: How do these NO adducts activate cytosolic sGC when their NO moiety is still outside the cell? In this review, we classify these compounds as ‘nitrodilators’, defined by their potent NO-mimetic vasoactivities despite not releasing requisite amounts of free NO. We propose that nitrodilators activate sGC via a preformed nitrodilator-activated NO store (NANOS) found within the vascular smooth muscle cell. We reinterpret vascular NO handling in the framework of this NANOS paradigm, and describe the knowledge gaps and perspectives of this novel model.

Optimized S-nitrosohemoglobin Synthesis in Red Blood Cells to Preserve Hypoxic Vasodilation Via βCys93.

Classic physiology links tissue hypoxia to oxygen delivery through control of microvascular blood flow (autoregulation of blood flow). Hemoglobin (Hb) serves both as the source of oxygen and the mediator of microvascular blood flow through its ability to release vasodilatory S-nitrosothiol (SNO) in proportion to degree of hypoxia. β-globin Cys93Ala (βCys93Ala) mutant mice deficient in S-nitrosohemoglobin (SNO-Hb) show profound deficits in microvascular blood flow and tissue oxygenation that recapitulate microcirculatory dysfunction in multiple clinical conditions. However, the means to replete SNO in mouse red blood cells (RBCs) to restore RBC function is not known. In particular, although methods have been developed to selectively S-nitrosylate βCys93 in human Hb and intact human RBCs, conditions have not been optimized for mouse RBCs that are used experimentally. Here we show that loading SNO onto Hb in mouse RBC lysates can be achieved with high stoichiometry and β-globin selectivity. However, S-nitrosylation of Hb within intact mouse RBCs is ineffective under conditions that work well with human RBCs, and levels of metHb are prohibitively high. We developed an optimized method that loads SNO in mouse RBCs to maintain vasodilation under hypoxia and shows that loss of SNO loading in βCys93Ala mutant RBCs results in reduced vasodilation. We also demonstrate that differences in SNO/met/nitrosyl Hb stoichiometry can account for differences in RBC function among studies. RBCs loaded with quasi-physiologic amounts of SNO-Hb will produce vasodilation proportionate to hypoxia, whereas RBCs loaded with higher amounts lose allosteric regulation, thus inducing vasodilation at both high and low oxygen level. SIGNIFICANCE STATEMENT: Red blood cells from mice exhibit poor hemoglobin S-nitrosylation under conditions used for human RBCs, frustrating tests of vasodilatory activity. Using an optimized S-nitrosylation protocol, mouse RBCs exhibit hypoxic vasodilation that is significantly reduced in hemoglobin βCys93Ala mutant RBCs that cannot carry S-nitrosothiol allosterically, providing genetic validation for the role of βCys93 in oxygen delivery.