scholarly journals Interactions Between Structural Remodeling and Hypertrophy in the Right Ventricle in Response to Pulmonary Arterial Hypertension

2019 ◽  
Vol 141 (9) ◽  
Author(s):  
Reza Avazmohammadi ◽  
Emilio A. Mendiola ◽  
David S. Li ◽  
Peter Vanderslice ◽  
Richard A. F. Dixon ◽  
...  
Keyword(s):  
Pulmonary Arterial Hypertension ◽  
Right Ventricle ◽  
Arterial Hypertension ◽  
Contractile Function ◽  
Pressure Overload ◽  
Right Heart Failure ◽  
Volumetric Growth ◽  
Structural Remodeling ◽  
Pulmonary Arterial ◽  
The Right

Pulmonary arterial hypertension (PAH) exerts substantial pressure overload on the right ventricle (RV), inducing RV remodeling and myocardial tissue adaptation often leading to right heart failure. The associated RV free wall (RVFW) adaptation involves myocardial hypertrophy, augmented intrinsic contractility, collagen fibrosis, and structural remodeling in an attempt to cope with pressure overload. If RVFW adaptation cannot maintain the RV stroke volume (SV), RV dilation will prevail as an exit mechanism, which usually decompensates RV function, leading to RV failure. Our knowledge of the factors determining the transition from the upper limit of RVFW adaptation to RV decompensation and the role of fiber remodeling events such as extracellular fibrosis and fiber reorientation in this transition remains very limited. Computational heart models that connect the growth and remodeling (G&R) events at the fiber and tissue levels with alterations in the organ-level function are essential to predict the temporal order and the compensatory level of the underlying mechanisms. In this work, building upon our recently developed rodent heart models (RHM) of PAH, we integrated mathematical models that describe volumetric growth of the RV and structural remodeling of the RVFW. The time-evolution of RV remodeling from control and post-PAH time points was simulated. The results suggest that the augmentation of the intrinsic contractility of myofibers, accompanied by an increase in passive stiffness of RVFW, is among the first remodeling events through which the RV strives to maintain the cardiac output. Interestingly, we found that the observed reorientation of the myofibers toward the longitudinal (apex-to-base) direction was a maladaptive mechanism that impaired the RVFW contractile pattern and advanced along with RV dilation at later stages of PAH. In fact, although individual fibers were more contractile post-PAH, the disruption in the optimal transmural fiber architecture compromised the effective contractile function of the RVFW, contributing to the depressed ejection fraction (EF) of the RV. Our findings clearly demonstrate the critical need for developing multiscale approaches that can model and delineate relationships between pathological alterations in cardiac function and underlying remodeling events across fiber, cellular, and molecular levels.

scholarly journals The striated muscles in pulmonary arterial hypertension: adaptations beyond the right ventricle

2015 ◽  
Vol 46 (3) ◽  
pp. 832-842 ◽  
Author(s):  
Emmy Manders ◽  
Silvia Rain ◽  
Harm-Jan Bogaard ◽  
M. Louis Handoko ◽  
Ger J.M. Stienen ◽  
...  
Keyword(s):  
Pulmonary Arterial Hypertension ◽  
Right Ventricle ◽  
Arterial Hypertension ◽  
Right Heart Failure ◽  
Exercise Intolerance ◽  
Muscle Dysfunction ◽  
Striated Muscles ◽  
Pulmonary Arterial ◽  
The Right ◽  
The Impact

Pulmonary arterial hypertension (PAH) is a fatal lung disease characterised by progressive remodelling of the small pulmonary vessels. The daily-life activities of patients with PAH are severely limited by exertional fatigue and dyspnoea. Typically, these symptoms have been explained by right heart failure. However, an increasing number of studies reveal that the impact of the PAH reaches further than the pulmonary circulation. Striated muscles other than the right ventricle are affected in PAH, such as the left ventricle, the diaphragm and peripheral skeletal muscles. Alterations in these striated muscles are associated with exercise intolerance and reduced quality of life. In this Back to Basics article on striated muscle function in PAH, we provide insight into the pathophysiological mechanisms causing muscle dysfunction in PAH and discuss potential new therapeutic strategies to restore muscle dysfunction.

scholarly journals Potts Shunt in Children With Familial Primary Pulmonary Hypertension: A Case Report and Brief Literature Review

2021 ◽  
Vol 9 (3) ◽  
pp. 247-254
Author(s):  
Mahya Mobinikhaledi ◽  
◽  
Ali Arjmand Shabestari ◽  
Yazdan Ghandi ◽  
◽  
...  
Keyword(s):  
Heart Failure ◽  
Pulmonary Hypertension ◽  
Pulmonary Arterial Hypertension ◽  
Right Ventricle ◽  
Arterial Hypertension ◽  
Medical Treatment ◽  
Right Heart Failure ◽  
Right Heart ◽  
Pulmonary Arterial ◽  
The Right

Introduction: The primary concern about Familial Pulmonary Arterial Hypertension (FPAH) is the development of right heart failure, which ultimately leads to sudden death. Despite recent advances in pharmacological therapy, the mortality rate in children is still high, emphasizing the importance of novel treatments. Moreover, there is still no definitive treatment for children with severe pulmonary hypertension. The consequences of right heart failure led to the proposal of a surgical approach, the Potts shunt, to decompress the right ventricle, providing shunting of deoxygenated blood to lower extremities and improving overall cardiac output. This surgical technique creates an anastomosis between the left pulmonary artery and the descending aorta, providing a palliative treatment to off-load the right ventricle. Case Presentation: We report an 11-year-old girl with familial pulmonary arterial hypertension and right ventricular failure who benefited from a Potts shunt with good mid-term results. The patient was diagnosed at the age of 5 when she had a history of fainting and persistent syncope. The patient was under medical treatment therapy with bosentan, sildenafil, acetylsalicylic acid, and warfarin for six years. The results of molecular genetic testing, which was confirmed with direct sequencing of the Bone Morphogenetic Protein Receptor Type 2 (BMPR2) gene, revealed a heterozygous pathogenic mutation. Since she was diagnosed with Pulmonary Arterial Hypertension (PAH), she lost her grandmother, an aunt, and father because of PAH. Her 14-year-old sister also had mutated the BMPR2 gene without developing FPAH. Conclusions: The Potts shunt provides an interventional step for palliation of patients with familial pulmonary hypertension and severe right heart failure refractory to medical treatment. It opens the door to the possibility of lung transplantation in the future. We did not see any complications within 6 years after placing the Potts shunt.

scholarly journals Effects of ovariectomy on antioxidant defence systems in the right ventricle of female rats with pulmonary arterial hypertension induced by monocrotaline

2018 ◽  
Vol 96 (3) ◽  
pp. 295-303 ◽  
Author(s):  
Rafaela Siqueira ◽  
Rafael Colombo ◽  
Adriana Conzatti ◽  
Alexandre Luz de Castro ◽  
Cristina Campos Carraro ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Pulmonary Arterial Hypertension ◽  
Right Ventricle ◽  
Protein Expression ◽  
Arterial Hypertension ◽  
Female Rats ◽  
Antioxidant Defenses ◽  
Thioredoxin 1 ◽  
Pulmonary Arterial ◽  
The Right

The aim of this study was to evaluate the impact of ovariectomy on oxidative stress in the right ventricle (RV) of female rats with pulmonary arterial hypertension (PAH) induced by monocrotaline (MCT). Rats were divided into 4 groups (n = 6 per group): sham (S), sham + MCT (SM), ovariectomized (O), and ovariectomized + MCT (OM). MCT (60 mg·kg−1 i.p.) was injected 1 week after ovariectomy or sham surgery. Three weeks later, echocardiographic analysis and RV catheterisation were performed. RV morphometric, biochemical, and protein expression analysis through Western blotting were done. MCT promoted a slight increase in pulmonary artery pressure, without differences between the SM and OM groups, but did not induce RV hypertrophy. RV hydrogen peroxide increased in the MCT groups, but SOD, CAT, and GPx activities were also enhanced. Non-classical antioxidant defenses diminished in ovariectomized groups, probably due to a decrease in the nuclear factor Nrf2. Hemoxygenase-1 and thioredoxin-1 protein expression was increased in the OM group compared with SM, being accompanied by an elevation in the estrogen receptor β (ER-β). Hemoxygenase-1 and thioredoxin-1 may be involved in the modulation of oxidative stress in the OM group, and this could be responsible for attenuation of PAH and RV remodeling.

scholarly journals MicroRNA-140 is elevated and mitofusin-1 is downregulated in the right ventricle of the Sugen5416/hypoxia/normoxia model of pulmonary arterial hypertension.

2016 ◽  
Vol 311 (3) ◽  
pp. H689-H698 ◽  
Author(s):  
Sachindra Raj Joshi ◽  
Vidhi Dhagia ◽  
Salina Gairhe ◽  
John G. Edwards ◽  
Ivan F. McMurtry ◽  
...  
Keyword(s):  
Pulmonary Arterial Hypertension ◽  
Right Ventricle ◽  
Arterial Hypertension ◽  
Systolic Pressure ◽  
Right Heart ◽  
Biochemical Processes ◽  
Pulmonary Arterial ◽  
Direct Target ◽  
The Right ◽  
Mitofusin 1

Heart failure, a major cause of morbidity and mortality in patients with pulmonary arterial hypertension (PAH), is an outcome of complex biochemical processes. In this study, we determined changes in microRNAs (miRs) in the right and left ventricles of normal and PAH rats. Using an unbiased quantitative miR microarray analysis, we found 1) miR-21-5p, miR-31-5 and 3p, miR-140-5 and 3p, miR-208b-3p, miR-221-3p, miR-222-3p, miR-702-3p, and miR-1298 were upregulated (>2-fold; P < 0.05) in the right ventricle (RV) of PAH compared with normal rats; 2) miR-31-5 and 3p, and miR-208b-3p were upregulated (>2-fold; P < 0.05) in the left ventricle plus septum (LV+S) of PAH compared with normal rats; 3) miR-187-5p, miR-208a-3p, and miR-877 were downregulated (>2-fold; P < 0.05) in the RV of PAH compared with normal rats; and 4) no miRs were up- or downregulated with >2-fold in LV+S compared with RV of PAH and normal. Upregulation of miR-140 and miR-31 in the hypertrophic RV was further confirmed by quantitative PCR. Interestingly, compared with control rats, expression of mitofusin-1 (MFN1), a mitochondrial fusion protein that regulates apoptosis, and which is a direct target of miR-140, was reduced in the RV relative to LV+S of PAH rats. We found a correlation between increased miR-140 and decreased MFN1 expression in the hypertrophic RV. Our results also demonstrated that upregulation of miR-140 and downregulation of MFN1 correlated with increased RV systolic pressure and hypertrophy. These results suggest that miR-140 and MFN1 play a role in the pathogenesis of PAH-associated RV dysfunction. Listen to this article's corresponding podcast at http://ajpheart.podbean.com/e/mir140-and-right-heart-hypertrophy/ .

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