Abstract 17396: RV Remodeling in Two Animal Models of Pulmonary Arterial Hypertension

Circulation ◽  
2018 ◽  
Vol 138 (Suppl_1) ◽  
Author(s):  
Xiaoyan Zhang ◽  
Daniela Velez-Rendon ◽  
Daniela Valdez-Jasso

Introduction: Right-ventricular function is a good indicator of pulmonary arterial hypertension (PAH) prognosis. By relating ventricular hemodynamics to wall mechanics, we aimed to discriminate the contributions of ventricular geometric remodeling and intrinsic changes in myocardial mechanical properties in two commonly used PAH animal models at end-systole (ES) and end-diastole (ED) to the maintenance of cardiac output during the early compensated phase. Methods: PAH was induced in 13 male Sprague-Dawley rats. The MCT group (N=4) was injected with a single dose of 60mg/kg of monoctroaline and kept in normoxia for 4 weeks. The SuHx group (N=9) was injected with a single dose of 20mg/kg of sugen, a VEGF inhibitor, and was placed on a hypoxia chamber for 3 weeks followed by 3 weeks of normoxia. 7 animals were used as a control group. In-vivo measurements of RV pressure and volume with preload changes were acquired. To relate ventricular pressure-volume relations to sarcomere mechanics, a computational model of the RV was developed. Using ventricular morphology and volume measurements from PAH groups, sarcomere material mechanics were adjusted to evaluate ES and ED functions in the treated animals. Results: ED pressures rose significantly in the treated groups (31.7 vs. 70.5 and 71.1 mmHg). ED and ES volumes remained the same in SuHx and CTL group, but increased significantly in the MCT group. RV hypertrophy increased in both PAH animal models, but it was significantly higher in the SuHx group. Even though differences in pressure, volume and morphology exist between the PAH groups, SV and CO were preserved in all treated animals. Model material parameters of increased in PAH, significantly in MCT maximal isometric tension. Conclusions: The model analysis suggests compensation to ESP rises was only possible due to a significant increase in the contractility of RV myocardium in the MCT and SuHx animals. No changes in diastolic function were found in the MCT animals, but there was an increase stiffness in the SuHx animals.

2017 ◽  
Vol 7 (2) ◽  
pp. 476-485 ◽  
Author(s):  
Kenny Schlosser ◽  
Mohamad Taha ◽  
Yupu Deng ◽  
Baohua Jiang ◽  
Lauralyn A McIntyre ◽  
...  

Translational research depends on the relevance of animal models and how well they replicate human disease. Here, we investigated plasma levels of three important pro-inflammatory cytokines (TNFα, IL-6, and MCP-1), known to be elevated in human pulmonary arterial hypertension (PAH), and systematically assessed their levels in PAH patients compared to five different rodent models of pulmonary hypertension (PH). A consistent immunoassay platform (Luminex xMAP) and source (Millipore) was used to measure all specimens. PAH patients (n = 29) exhibited significant elevations in all three cytokines (median [IQR] pg/mL; TNFα, 7.0 [4.8–11.7]; IL-6, 9.2 [3.8–17.2]; MCP-1, 109 [65–142]) versus healthy participants (n = 20) (median [IQR] pg/mL; TNFα, 3.0 [2.0–3.6]; IL-6, 1.7 [0.5–7.2]; MCP-1, 79 [49–93]. In contrast, mice with PH established after three weeks of hypoxia (n = 18) or SU5416 plus hypoxia (n = 20) showed no significant change in their plasma cytokine levels versus controls (n = 16), based on three to four independent experiments per group. Similarly, plasma cytokine levels were not elevated in rats with PH established three weeks after monocrotaline (n = 23), eight weeks after SU5416 alone (n = 10) or six to eight weeks after SU5416 plus hypoxia (n = 21) versus controls (n = 36 rats), based on three to eight independent experiments per group. Positive biologic control specimens from sepsis patients (n = 9), cecal-ligation and puncture (CLP)-induced septic mice (n = 6), and lipopolysaccharide-induced septic rats (n = 4) showed robust elevations in all three cytokines. This study suggests that animal models commonly used for the development of novel diagnostic and therapeutic approaches for PAH may have limited construct validity with respect to markers of systemic immune activation seen in human patients.


Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Samantha Torquato ◽  
Kiyotake Ishikawa ◽  
Jaume Aguerro ◽  
Bradley A Maron ◽  
Joseph Loscalzo ◽  
...  

Elevated levels of norepinephrine (NE) occur in pulmonary arterial hypertension (PAH) and are determined, in part, by the activity of catechol- O -methyltransferase (COMT). COMT degrades catecholamines, is negatively regulated by calcium, and is expressed by pulmonary artery endothelial cells (PAEC). As hyperaldosteronism occurs in PAH and aldosterone (ALDO) influences calcium levels, we hypothesized that ALDO decreases COMT activity to increase NE levels in PAH. Accordingly, human PAEC were treated with ALDO (10 -7 mol/L), a level that is achieved clinically in PAH, for up to 72 h. Compared to vehicle-treated PAEC, ALDO decreased COMT activity by 59.2 ± 6.2% (p<0.01) to increase NE levels in the medium (122.4 ± 11.8 vs. 210.7 ± 15.5 pg/mL/mg protein, p<0.01). This occurred as a result of an ALDO-mediated decrease in COMT protein expression by 52.6 ± 9.3% (p<0.01) as well as an increase in intracellular calcium levels (102.9 ± 21.0 vs. 167.7 ± 17.8 nmol/L, p<0.05) to inhibit activity. These effects were abrogated by coincubation with spironolactone. To determine the in vivo relevance of these findings, COMT was examined in the rat monocrotaline model of PAH with confirmed hyperALDO. COMT was decreased (47.6 ± 10.2 %control, p<0.05) in remodeled pulmonary arterioles with a concomitant increase in lung NE levels (432.8 ± 44.5 vs. 899.7 ± 34.2 pg/mL, p<0.01) compared to control rats. In the porcine pulmonary vein banding model of pulmonary hypertension (PH-pigs) with elevated mean pulmonary artery pressure (15[13-15] vs. 35[27-43], p<0.01) and pulmonary vascular resistance (PVR) index (1.97[1.74-2.28] vs. 5.78[2.61-8.75], p <0.05), ALDO levels were also increased (27.1 ± 5.1 vs. 60.8 ± 10.6 pg/mL, p<0.03) in advance of right heart failure as compared to sham controls. PH-pigs demonstrated a 48.3 ± 9.9% (p<0.02) decrease in pulmonary vascular COMT expression and an increase in NE levels (114.6 ± 20.2 vs. 1,622.6 ± 489.2 pg/mL, p<0.02) that correlated positively with ALDO levels (R 2 =0.58, p<0.02). These findings were confirmed in patients with PAH. Together, these data indicate that there is crosstalk in the pulmonary vasculature between ALDO and the sympathetic nervous system to regulate NE levels in PAH, and thus, have implications for therapeutic interventions.


Circulation ◽  
2008 ◽  
Vol 118 (suppl_18) ◽  
Author(s):  
Gopinath Sutendra ◽  
Sebastien Bonnet ◽  
Paulette Wright ◽  
Peter Dromparis ◽  
Alois Haromy ◽  
...  

Nogo was first identified as an inhibitor of neuronal axonal regeneration. Recently, Nogo-B was implicated in the proliferative and anti-apoptotic remodeling in systemic arteries; reduced Nogo-B expression was seen in remodeled mouse femoral arteries following injury. Pulmonary arterial hypertension (PAH) is also characterized by proliferative/anti-apoptotic remodeling in pulmonary arteries (PA), sparing systemic vessels. PAH PA smooth muscle cells (PASMC) are characterized by mitochondrial hyperpolarization (increased ΔΨm), decreased production of reactive oxygen species (ROS) (suppressing mitochondria-dependent apoptosis), down-regulation of Kv1.5 and activation of the transcription factor NFAT (promoting contraction and proliferation). We found that in contrast to systemic vessels, Nogo-B expression is significantly increased in vivo and in vitro in PAs and PASMCs from patients (n=6) and mice (n=42) with PAH, compared to normals. We hypothesized that Nogo is involved in the pathogenesis of PAH . Nogo −/− mice (n=7) had a normal phenotype and, in contrast to Nogo +/+ , did not develop chronic hypoxia (CH)-induced PAH assessed invasively (catheterization, RV/LV+Septum) and non-invasively (pulmonary artery acceleration time and treadmill performance) (n=7, Table ). CH- Nogo +/+ PASMC had the expected increase in ΔΨm (measured by TMRM), decreased ROS (MitoSOX), increased [Ca ++ ] i (FLUO3), decreased Kv1.5 (immunohistochemistry) and NFAT activation (nuclear translocation). None of these changes occurred in CH- Nogo −/− PASMC while all were induced in normoxic Nogo +/+ PASMC by adenoviral over-expression of Nogo-B . Heterozygote CH- Nogo +/− (n=7) values were between Nogo −/− and Nogo +/+ suggesting a gene dose-dependent effect. Nogo is over-expressed in human and rodent PAH and induces critical features of the PAH phenotype. Nogo targeting might represent a novel and selective therapeutic strategy for PAH. Table


Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Kenzo Ichimura ◽  
Tetsuya Matoba ◽  
Ryoji Nagahama ◽  
Kaku Nakano ◽  
Kenji Sunagawa ◽  
...  

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.


Nutrients ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 169
Author(s):  
María Callejo ◽  
Joan Albert Barberá ◽  
Juan Duarte ◽  
Francisco Perez-Vizcaino

Pulmonary arterial hypertension (PAH) is characterized by sustained vasoconstriction, vascular remodeling, inflammation, and in situ thrombosis. Although there have been important advances in the knowledge of the pathophysiology of PAH, it remains a debilitating, limiting, and rapidly progressive disease. Vitamin D and iron deficiency are worldwide health problems of pandemic proportions. Notably, these nutritional alterations are largely more prevalent in PAH patients than in the general population and there are several pieces of evidence suggesting that they may trigger or aggravate disease progression. There are also several case reports associating scurvy, due to severe vitamin C deficiency, with PAH. Flavonoids such as quercetin, isoflavonoids such as genistein, and other dietary polyphenols including resveratrol slow the progression of the disease in animal models of PAH. Finally, the role of the gut microbiota and its interplay with the diet, host immune system, and energy metabolism is emerging in multiple cardiovascular diseases. The alteration of the gut microbiota has also been reported in animal models of PAH. It is thus possible that in the near future interventions targeting the nutritional status and the gut dysbiosis will improve the outcome of these patients.


Respirology ◽  
2019 ◽  
Vol 24 (11) ◽  
pp. 1095-1103 ◽  
Author(s):  
Rebecca L. Harper ◽  
Suzanne Maiolo ◽  
Rebekah J. Ward ◽  
Jemma Seyfang ◽  
Michaelia P. Cockshell ◽  
...  

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Caixin Zhang ◽  
Pengbo Wang ◽  
Anaz Mohammed ◽  
Zhewen Zhou ◽  
Shuwen Zhang ◽  
...  

Pulmonary arterial hypertension (PAH) is a serious condition. However, prevailing therapeutic strategies are not effective enough to treat PAH. Therefore, finding an effective therapy is clearly warranted. Adipose-derived mesenchymal stem cells (ASCs) and ASCs-derived exosomes (ASCs-Exos) exert protective effects in PAH, but the underlying mechanism remains unclear. Using a coculture of ASCs and monocrotaline pyrrole (MCTP)-treated human pulmonary artery endothelial cells (HPAECs), we demonstrated that ASCs increased cell proliferation in MCTP-treated HPAECs. Results showed that ASCs-Exos improved proliferation of both control HPAECs and MCTP-treated HPAECs. In addition, by transfecting ASCs with antagomir we observed that low exosomal miR-191 expression inhibited HPAECs proliferation whereas the agomir improved. Similar results were observed in vivo using a monocrotaline (MCT)-induced PAH rat model following ASCs transplantation. And ASCs transplantation attenuated MCT-induced PAH albeit less than the antagomir treated group. Finally, we found that miR-191 repressed the expression of bone morphogenetic protein receptor 2 (BMPR2) in HPAECs and PAH rats. Thus, we conjectured that miR-191, in ASCs and ASCs-Exos, plays an important role in PAH via regulation of BMPR2. These findings are expected to contribute to promising therapeutic strategies for treating PAH in the future.


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