Imaging of the pulmonary circulation in the closed-chest rat using synchrotron radiation microangiography

2007 ◽  
Vol 102 (2) ◽  
pp. 787-793 ◽  
Author(s):  
Daryl O. Schwenke ◽  
James T. Pearson ◽  
Keiji Umetani ◽  
Kenji Kangawa ◽  
Mikiyasu Shirai
Keyword(s):  
Pulmonary Arterial Hypertension ◽  
Synchrotron Radiation ◽  
Arterial Hypertension ◽  
Pulmonary Circulation ◽  
Structural Changes ◽  
Dynamic Changes ◽  
Male Adult ◽  
Closed Chest ◽  
Pulmonary Vasoconstriction ◽  
Pulmonary Arterial

Structural changes of the pulmonary circulation during the pathogenesis of pulmonary arterial hypertension remain to be fully elucidated. Although angiography has been used for visualizing the pulmonary circulation, conventional angiography systems have considerable limitations for visualizing small microvessels (diameters < 200 μm), particularly within a closed-chest animal model. In this study we assess the effectiveness of monochromatic synchrotron radiation (SR) for microangiography of the pulmonary circulation in the intact-chest rat. Male adult Sprague-Dawley rats were anesthetized, and a catheter was positioned within the right ventricle, for administering iodinated contrast agent (Iomeron 350). Subsequently, microangiography of pulmonary arterial branches within the left lung was performed using monochromatic SR. Additionally, we assessed dynamic changes in vessel diameter during acute hypoxic (10% and 8% O2 for 4 min each) pulmonary vasoconstriction (HPV). Using SR we were able to visualize pulmonary microvessels with a diameter of <100 μm (the 4th generation of branching from the left axial artery). Acute hypoxia caused a significant decrease in the diameter of all vessels less than 500 μm. The greatest degree of pulmonary vasoconstriction was observed in vessels with a diameter between 200 and 300 μm. These results demonstrate the effectiveness of SR for visualizing pulmonary vessels in a closed-chest rat model and for assessing dynamic changes associated with HPV. More importantly, these observations implicate SR as an effective tool in future research for assessing gross structural changes associated with the pathogenesis of pulmonary arterial hypertension.

scholarly journals Echocardiography and Pulmonary Arterial Hypertension

2016 ◽  
Vol 68 (4) ◽  
Author(s):  
Eduardo Bossone ◽  
Rodolfo Citro ◽  
Alberto Ruggiero ◽  
Bettina Kuersten ◽  
Giovanni Gregorio ◽  
...  
Keyword(s):  
Pulmonary Arterial Hypertension ◽  
Arterial Hypertension ◽  
Structural Changes ◽  
Pulmonary Arteries ◽  
Progressive Increase ◽  
Accurate Estimate ◽  
Therapeutic Interventions ◽  
Wide Range ◽  
Advanced Stages ◽  
Pulmonary Arterial

Pulmonary Arterial Hypertension (PAH) is an heterogeneous condition brought on by a wide range of causes. It is characterized by structural changes in small pulmonary arteries, that produce a progressive increase in pulmonary artery pressure and pulmonary vascular resistance, ultimately leading to right ventricle failure and death. Given the non-specific nature of its early symptoms and signs, PAH is often diagnosed in its advanced stages. Along with a careful clinical assessment and an accurate electrocardiogram/Chest X-ray interpretation, echocardiography is an essential test in the evaluation of patient with PAH. In fact it not only provides an accurate estimate of pulmonary pressure at rest and during exercise, but may also help to exclude any secondary causes, predict the prognosis, monitor the efficacy of specific therapeutic interventions and detect the preclinical stage of the disease.

scholarly journals Endothelin research and the discovery of macitentan for the treatment of pulmonary arterial hypertension

2016 ◽  
Vol 311 (4) ◽  
pp. R721-R726 ◽  
Author(s):  
Martine Clozel
Keyword(s):  
Pulmonary Arterial Hypertension ◽  
Arterial Hypertension ◽  
Structural Changes ◽  
Term Treatment ◽  
Vasopressin Release ◽  
Long Term Treatment ◽  
Pulmonary Arterial ◽  
Kinetics Of

Endothelin receptor antagonists (ERAs) are used for the treatment of pulmonary arterial hypertension (PAH). Macitentan, a dual (ETA+ETB) ERA approved for the long-term treatment of PAH, was discovered through a tailored research program aimed at improving efficacy and safety over the existing ERAs. The goal of improved efficacy was based on the understanding that not only the ETA receptor but also the ETB receptor contributed to the hemodynamic and structural changes induced by endothelin-1 (ET-1) in pathological conditions and on the predefined requirements for optimal tissue penetration and binding kinetics of the antagonist. The goal of improved safety was based on the discovery of the role of ETB receptors in vascular permeability and vasopressin release and on the elucidation of the mechanism by which bosentan (the first approved oral dual ETA/ETB ERA) caused liver enzyme changes. Our intention was to design a molecule that would block ETA and ETB receptors optimally and would not interfere with bile salt elimination. This review takes us through the drug discovery journey that led to the discovery, development, and registration of macitentan.

Upregulation of Na+/Ca2+ exchanger contributes to the enhanced Ca2+ entry in pulmonary artery smooth muscle cells from patients with idiopathic pulmonary arterial hypertension

2007 ◽  
Vol 292 (6) ◽  
pp. C2297-C2305 ◽  
Author(s):  
Shen Zhang ◽  
Hui Dong ◽  
Lewis J. Rubin ◽  
Jason X.-J. Yuan
Keyword(s):  
Smooth Muscle ◽  
Pulmonary Arterial Hypertension ◽  
Pulmonary Artery ◽  
Arterial Hypertension ◽  
Smooth Muscle Cells ◽  
Idiopathic Pulmonary Arterial Hypertension ◽  
Reverse Mode ◽  
Pulmonary Vasoconstriction ◽  
Pulmonary Arterial ◽  
Pulmonary Artery Smooth Muscle

A rise in cytosolic Ca2+ concentration ([Ca2+]cyt) in pulmonary artery smooth muscle cells (PASMC) is a trigger for pulmonary vasoconstriction and a stimulus for PASMC proliferation and migration. Multiple mechanisms are involved in regulating [Ca2+]cyt in human PASMC. The resting [Ca2+]cyt and Ca2+ entry are both increased in PASMC from patients with idiopathic pulmonary arterial hypertension (IPAH), which is believed to be a critical mechanism for sustained pulmonary vasoconstriction and excessive pulmonary vascular remodeling in these patients. Here we report that protein expression of NCX1, an NCX family member of Na+/Ca2+ exchanger proteins is upregulated in PASMC from IPAH patients compared with PASMC from normal subjects and patients with other cardiopulmonary diseases. The Na+/Ca2+ exchanger operates in a forward (Ca2+ exit) and reverse (Ca2+ entry) mode. By activating the reverse mode of Na+/Ca2+ exchange, removal of extracellular Na+ caused a rapid increase in [Ca2+]cyt, which was significantly enhanced in IPAH PASMC compared with normal PASMC. Furthermore, passive depletion of intracellular Ca2+ stores using cyclopiazonic acid (10 μM) not only caused a rise in [Ca2+]cyt due to Ca2+ influx through store-operated Ca2+ channels but also mediated a rise in [Ca2+]cyt via the reverse mode of Na+/Ca2+ exchange. The upregulated NCX1 in IPAH PASMC led to an enhanced Ca2+ entry via the reverse mode of Na+/Ca2+ exchange, but did not accelerate Ca2+ extrusion via the forward mode of Na+/Ca2+ exchange. These observations indicate that the upregulated NCX1 and enhanced Ca2+ entry via the reverse mode of Na+/Ca2+ exchange are an additional mechanism responsible for the elevated [Ca2+]cyt in PASMC from IPAH patients.

scholarly journals Pulmonary hypertension. Clarifying concepts

ANALES RANM ◽  
2021 ◽  
Vol 138 (138(02)) ◽  
pp. 137-142
Author(s):  
J.R. de Berrazueta Fernández
Keyword(s):  
Pulmonary Hypertension ◽  
Pulmonary Arterial Hypertension ◽  
Arterial Hypertension ◽  
Structural Changes ◽  
Systolic Pressure ◽  
Pulmonary Artery Systolic Pressure ◽  
Current Classification ◽  
Mean Pressure ◽  
Pulmonary Arterial ◽  
The Difference

Pulmonary Arterial Hypertension is a central syndrome produced by a large number of cardiological, pulmonary, and systemic diseases that affect the lung bed. It is defined by the existence of a pulmonary artery systolic pressure greater than 30 or a mean pressure greater than 25 mmHg. This definition criterion has been maintained for more than 60 years. However, the current classification includes two concepts: a Pulmonary Arterial Hypertension (PAH) with two groups of disorders in which only pulmonary arterial resistance increases and five groups that are classified as Pulmonary Hypertension (PH): PH Secondary to Pulmonary Veno-occlusive Disease , HP secondary to diseases of the left side of the heart; HP Obliterative diseases and pulmonary hypoxemia; HP Pulmonary thrombus occlusive diseases, and a group of multifactorial HP. The difference is found in how the different diseases affect the pulmonary vascular bed, and how they alter the physiology or behavior of pulmonary resistance, which are the concepts that must be handled when talking about this syndrome and whose structural changes and management we will discuss in a later article.

scholarly journals Pulmonary hypertension: reasonable selection of specific therapy

2018 ◽  
Vol 15 (1) ◽  
pp. 45-50
Author(s):  
N A Karoli ◽  
S I Sazhnova ◽  
A P Rebrov
Keyword(s):  
Pulmonary Hypertension ◽  
Pulmonary Arterial Hypertension ◽  
Arterial Hypertension ◽  
Structural Changes ◽  
Pulmonary Arteries ◽  
Endothelin Receptor Antagonists ◽  
Endothelin Receptor ◽  
Receptor Antagonists ◽  
Pulmonary Vasodilator ◽  
Pulmonary Arterial

Pulmonary hypertension is characterized with persistent increase in pulmonary vascular resistance leading to progressive worsening of right ventricular failure and death. The basis for pulmonary arterial hypertension is structural changes in pulmonary arteries and arterioles caused by endothelial dysfunction. Endothelin-1 is the main pathogenic trigger of pulmonary hypertension and potential target for therapeutic exposure. The efficacy of endothelin receptor antagonists is proved in various preclinical and clinical studies. In patients with pulmonary arterial hypertension, the efficacy of dual and selective endothelin receptor antagonists is comparable despite the varied activity against various receptors. Bosentan is the most widely used pulmonary vasodilator which improves exercise tolerance and decelerates disease progression.

scholarly journals MicroRNA-mediated downregulation of K+ channels in pulmonary arterial hypertension

2020 ◽  
Vol 318 (1) ◽  
pp. L10-L26 ◽  
Author(s):  
Aleksandra Babicheva ◽  
Ramon J. Ayon ◽  
Tengteng Zhao ◽  
Jose F. Ek Vitorin ◽  
Nicole M. Pohl ◽  
...  
Keyword(s):  
Pulmonary Arterial Hypertension ◽  
Arterial Hypertension ◽  
Pulmonary Vasoconstriction ◽  
Channel Expression ◽  
Pulmonary Arterial ◽  
Direct Target ◽  
Non Coding Rnas ◽  
Pulmonary Artery Smooth Muscle ◽  
And Function ◽  
Channel Currents

Downregulated expression of K+ channels and decreased K+ currents in pulmonary artery smooth muscle cells (PASMC) have been implicated in the development of sustained pulmonary vasoconstriction and vascular remodeling in patients with idiopathic pulmonary arterial hypertension (IPAH). However, it is unclear exactly how K+ channels are downregulated in IPAH-PASMC. MicroRNAs (miRNAs) are small non-coding RNAs that are capable of posttranscriptionally regulating gene expression by binding to the 3′-untranslated regions of their targeted mRNAs. Here, we report that specific miRNAs are responsible for the decreased K+ channel expression and function in IPAH-PASMC. We identified 3 miRNAs (miR-29b, miR-138, and miR-222) that were highly expressed in IPAH-PASMC in comparison to normal PASMC (>2.5-fold difference). Selectively upregulated miRNAs are correlated with the decreased expression and attenuated activity of K+ channels. Overexpression of miR-29b, miR-138, or miR-222 in normal PASMC significantly decreased whole cell K+ currents and downregulated voltage-gated K+ channel 1.5 (KV1.5/KCNA5) in normal PASMC. Inhibition of miR-29b in IPAH-PASMC completely recovered K+ channel function and KV1.5 expression, while miR-138 and miR-222 had a partial or no effect. Luciferase assays further revealed that KV1.5 is a direct target of miR-29b. Additionally, overexpression of miR-29b in normal PASMC decreased large-conductance Ca2+-activated K+ (BKCa) channel currents and downregulated BKCa channel β1 subunit (BKCaβ1 or KCNMB1) expression, while inhibition of miR-29b in IPAH-PASMC increased BKCa channel activity and BKCaβ1 levels. These data indicate upregulated miR-29b contributes at least partially to the attenuated function and expression of KV and BKCa channels in PASMC from patients with IPAH.

scholarly journals Cellular senescence impairs the reversibility of pulmonary arterial hypertension

2020 ◽  
Vol 12 (554) ◽  
pp. eaaw4974 ◽  
Author(s):  
Diederik E. van der Feen ◽  
Guido P. L. Bossers ◽  
Quint A. J. Hagdorn ◽  
Jan-Renier Moonen ◽  
Kondababu Kurakula ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Pulmonary Arterial Hypertension ◽  
Arterial Hypertension ◽  
Structural Changes ◽  
Human Situation ◽  
Vascular Phenotype ◽  
Pulmonary Arterial ◽  
End Stage ◽  
Irreversible Nature

Pulmonary arterial hypertension (PAH) in congenital cardiac shunts can be reversed by hemodynamic unloading (HU) through shunt closure. However, this reversibility potential is lost beyond a certain point in time. The reason why PAH becomes irreversible is unknown. In this study, we used MCT+shunt-induced PAH in rats to identify a dichotomous reversibility response to HU, similar to the human situation. We compared vascular profiles of reversible and irreversible PAH using RNA sequencing. Cumulatively, we report that loss of reversibility is associated with a switch from a proliferative to a senescent vascular phenotype and confirmed markers of senescence in human PAH-CHD tissue. In vitro, we showed that human pulmonary endothelial cells of patients with PAH are more vulnerable to senescence than controls in response to shear stress and confirmed that the senolytic ABT263 induces apoptosis in senescent, but not in normal, endothelial cells. To support the concept that vascular cell senescence is causal to the irreversible nature of end-stage PAH, we targeted senescence using ABT263 and induced reversal of the hemodynamic and structural changes associated with severe PAH refractory to HU. The factors that drive the transition from a reversible to irreversible pulmonary vascular phenotype could also explain the irreversible nature of other PAH etiologies and provide new leads for pharmacological reversal of end-stage PAH.

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