scholarly journals Effects of acute Rho kinase inhibition on chronic hypoxia-induced changes in proximal and distal pulmonary arterial structure and function

2011 ◽  
Vol 110 (1) ◽  
pp. 188-198 ◽  
Author(s):  
Rebecca R. Vanderpool ◽  
Ah Ram Kim ◽  
Robert Molthen ◽  
Naomi C. Chesler
Keyword(s):  
Pulmonary Artery ◽  
Pulmonary Arteries ◽  
Rho Kinase ◽  
Pressure Flow ◽  
Kinase Inhibition ◽  
Pulmonary Vasoconstriction ◽  
Pulsatile Pressure ◽  
Arterial Structure ◽  
Pulmonary Arterial ◽  
Induced Changes

Hypoxic pulmonary hypertension (HPH) is initially a disease of the small pulmonary arteries. Its severity is usually quantified by pulmonary vascular resistance (PVR). Acute Rho kinase inhibition has been found to reduce PVR toward control values in animal models, suggesting that persistent pulmonary vasoconstriction is the dominant mechanism for increased PVR. However, HPH may also cause proximal arterial changes, which are relevant to right ventricular (RV) afterload. RV afterload can be quantified by pulmonary vascular impedance, which is obtained via spectral analysis of pulsatile pressure-flow relationships. To determine the effects of HPH independent of persistent pulmonary vasoconstriction in proximal and distal arteries, we quantified pulsatile pressure-flow relationships before and after acute Rho kinase inhibition and measured pulmonary arterial structure with microcomputed tomography. In control lungs, Rho kinase inhibition decreased 0 Hz impedance (Z0), which is equivalent to PVR, from 2.1 ± 0.4 to 1.5 ± 0.2 mmHg·min·ml−1 ( P < 0.05) and tended to increase characteristic impedance (ZC) from 0.21 ± 0.01 to 0.22 ± 0.01 mmHg·min·ml−1. In HPH lungs, Rho kinase inhibition decreased Z0 ( P < 0.05) without affecting ZC. Microcomputed tomography measurements performed on lungs after acute Rho kinase inhibition demonstrated that HPH significantly decreased the unstressed diameter of the main pulmonary artery (760 ± 60 vs. 650 ± 80 μm; P < 0.05), decreased right pulmonary artery compliance, and reduced the frequency of arteries of diameter 50–100 μm (both P < 0.05). These results demonstrate that acute Rho kinase inhibition reverses many but not all HPH-induced changes in distal pulmonary arteries but does not affect HPH-induced changes in the conduit arteries that impact RV afterload.

Relation of geometry to certain aspects of hydrodynamics in larger pulmonary arteries

1962 ◽  
Vol 17 (3) ◽  
pp. 492-496 ◽  
Author(s):  
Donald L. Fry ◽  
Dali J. Patel ◽  
Flavio M. De Freitas
Keyword(s):  
Pulmonary Artery ◽  
Pulmonary Arteries ◽  
Arterial Tree ◽  
Pressure Flow ◽  
Irrotational Flow ◽  
Blood Flows ◽  
Bernoulli’S Equation ◽  
Boundary Measurements ◽  
Fluid Boundary ◽  
Pulmonary Arterial

Pressure-flow relationships in the major pulmonary artery of the dog associated with accelerations imposed on flow by the geometry of vessel walls were evaluated. Assuming irrotational flow, the pressure-flow relationships may be evaluated by numerical substitution of fluid boundary measurements into Bernoulli's equation. Fluid boundary dimensions were obtained from Jeltrate casts of the pulmonary arterial tree in eight dogs. The results indicate that significant pressure differences may occur in the pulmonary artery at peak systolic blood flows due to nonuniformity and curvature of these vessels. Submitted on December 4, 1961

State-of-the-art pulmonary arterial imaging – Part 2

VASA ◽  
2018 ◽  
Vol 47 (5) ◽  
pp. 361-375 ◽  
Author(s):  
Harold Goerne ◽  
Abhishek Chaturvedi ◽  
Sasan Partovi ◽  
Prabhakar Rajiah
Keyword(s):  
Pulmonary Artery ◽  
State Of The Art ◽  
Therapy Monitoring ◽  
Pulmonary Arteries ◽  
Imaging Modalities ◽  
Cross Sectional ◽  
Multiple Imaging ◽  
Cross Sectional Imaging ◽  
Pulmonary Arterial ◽  
Arterial Imaging

Abstract. Although pulmonary embolism is the most common abnormality of the pulmonary artery, there is a broad spectrum of other congenital and acquired pulmonary arterial abnormalities. Multiple imaging modalities are now available to evaluate these abnormalities of the pulmonary arteries. CT and MRI are the most commonly used cross-sectional imaging modalities that provide comprehensive information on several aspects of these abnormalities, including morphology, function, risk-stratification and therapy-monitoring. In this article, we review the role of state-of-the-art pulmonary arterial imaging in the evaluation of non-thromboembolic disorders of pulmonary artery.

Inhibition of hypoxic pulmonary vasoconstriction by antagonists of store-operated Ca2+ and nonselective cation channels

2005 ◽  
Vol 289 (1) ◽  
pp. L5-L13 ◽  
Author(s):  
Letitia Weigand ◽  
Joshua Foxson ◽  
Jian Wang ◽  
Larissa A. Shimoda ◽  
J. T. Sylvester
Keyword(s):  
Hypoxic Pulmonary Vasoconstriction ◽  
Acute Hypoxia ◽  
Pulmonary Arteries ◽  
Cation Channels ◽  
Pulmonary Vasoconstriction ◽  
Nonselective Cation Channels ◽  
Pressor Responses ◽  
Intracellular Ca ◽  
Pulmonary Arterial

Previous studies indicated that acute hypoxia increased intracellular Ca2+ concentration ([Ca2+]i), Ca2+ influx, and capacitative Ca2+ entry (CCE) through store-operated Ca2+ channels (SOCC) in smooth muscle cells from distal pulmonary arteries (PASMC), which are thought to be a major locus of hypoxic pulmonary vasoconstriction (HPV). Moreover, these effects were blocked by Ca2+-free conditions and antagonists of SOCC and nonselective cation channels (NSCC). To test the hypothesis that in vivo HPV requires CCE, we measured the effects of SOCC/NSCC antagonists (SKF-96365, NiCl2, and LaCl3) on pulmonary arterial pressor responses to 2% O2 and high-KCl concentrations in isolated rat lungs. At concentrations that blocked CCE and [Ca2+]i responses to hypoxia in PASMC, SKF-96365 and NiCl2 prevented and reversed HPV but did not alter pressor responses to KCl. At 10 μM, LaCl3 had similar effects, but higher concentrations (30 and 100 μM) caused vasoconstriction during normoxia and potentiated HPV, indicating actions other than SOCC blockade. Ca2+-free perfusate and the voltage-operated Ca2+ channel (VOCC) antagonist nifedipine were potent inhibitors of pressor responses to both hypoxia and KCl. We conclude that HPV required influx of Ca2+ through both SOCC and VOCC. This dual requirement and virtual abolition of HPV by either SOCC or VOCC antagonists suggests that neither channel provided enough Ca2+ on its own to trigger PASMC contraction and/or that during hypoxia, SOCC-dependent depolarization caused secondary activation of VOCC.

Abstract 15120: Nanoparticle-Mediated Delivery of Pitavastatin into Small Pulmonary Arteies by Intravenous Administration Attenuated the Progression of Already Established Monocrotaline-induced Pulmonary Arterial Hypertension in Rats

Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Kenzo Ichimura ◽  
Tetsuya Matoba ◽  
Ryoji Nagahama ◽  
Kaku Nakano ◽  
Kenji Sunagawa ◽  
...  
Keyword(s):  
Pulmonary Arterial Hypertension ◽  
Pulmonary Artery ◽  
Arterial Hypertension ◽  
Intravenous Administration ◽  
Pulmonary Arteries ◽  
Intratracheal Instillation ◽  
Poly Lactic Acid ◽  
Bolus Administration ◽  
Sprague Dawley ◽  
Pulmonary Arterial

Background: Pulmonary arterial hypertension (PAH) is an intractable disease of small pulmonary artery in which multiple pathogenetic factors are involved. We have previously reported that poly(lactic acid/glycolic acid) (PLGA) nanoparticle (NP)-mediated targeting of pitavastatin into lungs by intratracheal instillation attenuated the development of PAH. In the present study we examined the effects of intravenous treatment with pitavastatin-NPs on the progression of already established PAH induced by monocrotaline (MCT). Methods and Results: Male Sprague-Dawley rats (200 to 230 g) were injected subcutaneously with 60 mg/kg MCT to induce PAH. At day 17 after MCT injection when PAH had been already established, animals were randomly divided into 4 groups, which treated with intravenous daily bolus administration of the following drugs for consecutive 4 days from 17 to 20 days after MCT injection; 1) vehicle, 2) FITC-NPs, 3) pitavastatin alone (1, 3, 10 or 30 mg/kg), or 4) pitavastatin-NPs (containing 1 or 3 mg/kg pitavastatin). Treatment with pitavastatin-NPs, but not with pitavastatin alone attenuated the progression of established PAH (Fig. A) associated with the reduction of inflammation and small pulmonary artery remodeling (stenosis and obstruction of pulmonary arterial branches) (Fig. B). In trace experiments, intravenous administration of FITC-NPs revealed the targeting of FITC-NPs into small pulmonary artery in rats with MCT-induced PAH, but not in normal animals. Importantly, in a separate protocol, treatment with pitavastatin-NPs improved the survival rate at day 35 (30% in pitavastatin-NP group vs. 61% in FITC-NP group, P<0.05 by Kaplan-Meier). Conclusion: A novel NP-mediated targeting of pitavastatin into small pulmonary arteries by intravenous administration attenuated the progression of established PAH and improved survival associated with anti-inflammatory and anti-remodeling effects in a rat model of MCT-induced PAH.

Endothelin-1 upregulates activin receptor-like kinase-1 expression via Gi/RhoA/Sp-1/Rho kinase pathways at transcriptional and post-transcriptional levels in human pulmonary arterial endothelial cells

2020 ◽  
Author(s):  
Koichi Sugimoto ◽  
Tetsuro Yokokawa ◽  
Tomofumi Misaka ◽  
Takashi Kaneshiro ◽  
Shinya Yamada ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Quantitative Polymerase Chain Reaction ◽  
Rho Kinase ◽  
Luciferase Assay ◽  
Activin Receptor ◽  
Rhoa Activation ◽  
Pulmonary Vasoconstriction ◽  
Receptor Like Kinase ◽  
Pulmonary Arterial ◽  
Arterial Endothelial Cells

Abstract BackgroundsPulmonary arterial hypertension (PAH) is a disease with poor prognosis that is characterized by pulmonary vasoconstriction and organic stenosis due to abnormal proliferation of pulmonary vascular cells. It has been demonstrated that endothelin (ET)-1 induces pulmonary vasoconstriction through activation of RhoA. Moreover, we previously demonstrated that Gi, a heterotrimeric G protein, functions upstream of RhoA activation. A gene mutation of activin receptor-like kinase (ACVRL)-1 is recognized in idiopathic or heritable PAH patients. However, little is known about the association between ET-1 and ACVRL-1. In the present study, we investigated the effect of ET-1 on ACVRL-1 expression and aimed to delineate the involvement of the Gi/RhoA/Rho kinase pathway.MethodsET-1 was added to culture medium of human pulmonary arterial endothelial cells (PAECs), and ACVRL-1 expression levels were analyzed using western blotting and quantitative polymerase chain reaction. The promoter activity of ACVRL-1 was evaluated by dual luciferase assay. Before adding ET-1 to the PAECs, pretreatment with pertussis toxin (PTX) or exoenzyme C3 transferase (C3T) was performed for the inhibition of Gi or RhoA, respectively. Rho kinase was inhibited by Y27632. Active form of RhoA (GTP-RhoA) was assessed by pull-down assay.ResultsACVRL-1 expression was increased by ET-1 in the PAECs. Pull-down assay revealed that ET-1 rapidly induced a GTP-loading of RhoA. The ET-1-induced RhoA activation was suppressed by pretreatment with PTX or C3T. Further, PTX, C3T, and Y27632 suppressed the ET-1-induced ACVRL-1 expression. The activity of ACVRL-1 promotor and the lifespan of ACVRL-1 mRNA was increased by ET-1. Sp-1, which is one of the transcriptional factors of ACVRL-1, peaked 15 min after adding ET-1 to the PAECs. PTX and C3T prevented the increase of Sp-1 induced by ET-1.ConclusionThe present study demonstrated that ET-1 increases ACVRL-1 expression at the transcriptional and post-transcriptional levels in human PAECs via the Gi/RhoA/Rho kinase pathway with involvement of Sp-1.

Effect of hypoxia on pulmonary artery pressure of dogs

1964 ◽  
Vol 207 (6) ◽  
pp. 1314-1318 ◽  
Author(s):  
Benson R. Wilcox ◽  
W. Gerald Austen ◽  
Harvey W. Bender
Keyword(s):  
Pulmonary Artery ◽  
Arterial Pressure ◽  
Pulmonary Artery Pressure ◽  
Pulmonary Arterial Pressure ◽  
Venous Pressure ◽  
Artery Pressure ◽  
Pulmonary Vasoconstriction ◽  
Systemic Hypoxia ◽  
Pump Output ◽  
Pulmonary Arterial

The mechanism by which the pulmonary artery pressure rises in response to hypoxia has never been clearly demonstrated. This problem was reinvestigated in experiments utilizing separate pulmonary and systemic perfusion systems. These vascular beds were perfused in such a fashion that a change in pulmonary artery pressure could only result from changes in vasomotor tone. Alveolar-pulmonary vein hypoxia was usually associated with a slight fall in pulmonary artery pressure. Systemic hypoxia resulted in elevation of pulmonary arterial pressure in 10 of the 12 animals tested with a constant-flow and constant-pulmonary venous pressure. In addition, all animals with systemic desaturation showed an increased venous return. When the "cardiac output" (pump output) was increased to match this return, the elevation in pulmonary artery pressure increased. It was concluded that the pulmonary arterial pressure elevation seen with hypoxia is the result of active pulmonary vasoconstriction coupled with an increased pulmonary blood flow.

Sex Differences in Right Ventricular-Vascular Coupling and Pulmonary Artery Impedance in Response to Chronic Hypoxia and Recovery

2012 ◽  
Author(s):  
Aiping Liu ◽  
Lian Tian ◽  
Diana M. Tabima ◽  
Naomi C. Chesler
Keyword(s):  
Pulmonary Artery ◽  
Chronic Hypoxia ◽  
Pulmonary Arteries ◽  
Pulmonary Artery Hypertension ◽  
Vascular Impedance ◽  
Female Predominance ◽  
Collagen Accumulation ◽  
Dominant Disease ◽  
Pulmonary Arterial

Pulmonary artery hypertension (PAH) is a female dominant disease (the female-to-male ratio is 4:1), characterized by small distal pulmonary arterial narrowing and large proximal arterial stiffening, which increase right ventricle (RV) afterload and ultimately lead to RV failure [1,2]. Our recent studies have shown that collagen accumulation induced by chronic hypoxia increases the stiffness of the large extralobar pulmonary arteries (PAs) [3], and affects pulmonary vascular impedance (PVZ) [4]. The role of collagen in the female predominance in developing PAH has not been explored to date.

Effect of selective embolization of various sized pulmonary arteries in dogs

1963 ◽  
Vol 204 (4) ◽  
pp. 619-625 ◽  
Author(s):  
John W. Hyland ◽  
George T. Smith ◽  
Lockhart B. McGuire ◽  
Donald C. Harrison ◽  
Florence W. Haynes ◽  
...  
Keyword(s):  
Pulmonary Embolism ◽  
Pulmonary Hypertension ◽  
Pulmonary Artery ◽  
Pulmonary Arteries ◽  
Internal Diameter ◽  
Polystyrene Spheres ◽  
Selective Embolization ◽  
Blood Clots ◽  
Pulmonary Arterial ◽  
The Right

Pulmonary embolism was produced in 30 closed-chest 8-kg dogs with polystyrene spheres, glass beads, or blood clots of precise graded size. The sizes matched selectively the internal diameter of pulmonary arteries from lobar branches (5–6 mm) down to atrial arteries (0.17 mm). Emboli were injected into the right atrium until the pressure in the pulmonary artery rose 5–10 mm Hg. The number of emboli of a given size required to produce this incipient pulmonary hypertension was compared with the number of vessels of that same size as determined from the literature as well as by postmortem injection with Schlesinger mass. The number of emboli bore a constant relation to the number of vessels of that same size. With each size, the majority of vessels had to be occluded before pulmonary hypertension appeared. This was true even in the absence of anesthesia. The results support the thesis that mechanical blockade rather than vasoconstriction is the mechanism by which pulmonary hypertension is produced by emboli occluding pulmonary arterial (as opposed to arteriolar) vessels.

Vagal control of pulmonary vascular resistance in the turtle Chrysemys scripta

1977 ◽  
Vol 55 (2) ◽  
pp. 359-367 ◽  
Author(s):  
William K. Milsom ◽  
B. Lowell Langille ◽  
David R. Jones
Keyword(s):  
Pulmonary Artery ◽  
Pulmonary Vascular Resistance ◽  
Vascular Resistance ◽  
Sympathetic Innervation ◽  
Pulmonary Arteries ◽  
Lung Parenchyma ◽  
Distal Segment ◽  
Cholinergic Innervation ◽  
Pulmonary Flow ◽  
Induced Changes

We have directly examined the control of pulmonary vascular resistance in the turtle Chrysemys scripta to determine the way in which pulmonary vasoregulation is achieved. The pulmonary circulation of the turtle Chrysemys scripta receives a strong excitatory cholinergic innervation from the vagus nerve. The major site of vasoconstrictor activity is in the extrinsic pulmonary artery proximal to the lung with only weak constrictor activity evident in the intrinsic arteries and arterioles within the lung parenchyma. No cholinergic innervation is evident in the segment of the extrinsic pulmonary artery proximal to the origin of the arterial ligament (ligamentum Botalli) and all vagally induced changes in flow resistance reside in the much narrower segment distal to this site. Vagal stimulation in an intact preparation produces sufficient constriction in the distal segment of extrinsic pulmonary artery to totally occlude pulmonary flow. The pulmonary arteries appear to be devoid of sympathetic innervation.

Fentanyl Attenuates α1B-Adrenoceptor–Mediated Pulmonary Artery Contraction

2005 ◽  
Vol 103 (2) ◽  
pp. 327-334 ◽  
Author(s):  
Ju-Tae Sohn ◽  
Xueqin Ding ◽  
Daniel F. McCune ◽  
Dianne M. Perez ◽  
Paul A. Murray
Keyword(s):  
Pulmonary Artery ◽  
Isometric Tension ◽  
Binding Studies ◽  
Response Curves ◽  
Vasoconstrictor Response ◽  
Adrenoceptor Agonist ◽  
Competition Binding ◽  
Dose Dependent Fashion ◽  
Pulmonary Arterial ◽  
Induced Changes

Background The authors tested the hypothesis that the intravenous anesthetic fentanyl would attenuate the pulmonary vasoconstrictor response to alpha1-adrenoceptor activation. They also investigated the alpha1-adrenoceptor subtypes that could potentially mediate this effect of fentanyl. Methods Endothelium-denuded canine pulmonary arterial rings were suspended for isometric tension recording. Dose-response curves for the alpha1-adrenoceptor agonist phenylephrine were generated in the absence and presence of fentanyl. The effects of inhibiting alpha2 (rauwolscine), alpha1 (prazosin), alpha1A (5-methylurapidil), alpha1B (chloroethylclonidine), and alpha1D (BMY 7378) adrenoceptors on phenylephrine contraction were also investigated. Receptor "protection" studies were performed to investigate the specific role of alpha1B adrenoceptors in mediating fentanyl-induced changes in phenylephrine contraction. Finally, competition binding studies were performed in rat-1 fibroblasts stably transfected with human alpha1-adrenoceptor complementary DNAs corresponding to the alpha1A-, alpha1B-, or alpha1D-adrenoceptor subtypes to directly assess whether fentanyl can compete for the alpha1-adrenoceptor activation pocket. Results Fentanyl attenuated phenylephrine contraction in a dose-dependent fashion. Rauwolscine had no effect on phenylephrine contraction. Phenylephrine contraction was inhibited by prazosin and abolished by chloroethylclonidine but was relatively resistant to inhibition by 5-methylurapidil and BMY 7378. Pretreatment with fentanyl before exposure to chloroethylclonidine increased the maximal contractile response to phenylephrine compared to chloroethylclonidine pretreatment alone. Competition binding studies revealed that fentanyl binds to all three alpha1-adrenoceptor subtypes, with a fivefold greater affinity for the alpha1B-adrenoceptor compared with the alpha1D-adrenoceptor subtype. Conclusion Phenylephrine-induced contraction is primarily mediated by alpha1B-adrenoceptor activation in canine pulmonary artery. Fentanyl attenuates phenylephrine contraction by binding to alpha1B adrenoceptors.

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