scholarly journals Rapamycin Improves Vascular Remodeling in a Controlled Rat Model of Monocrotaline-induced Pulmonary Hypertension

Author(s):  
A Sengul ◽  
C Vural ◽  
S Arkan ◽  
C Ozer ◽  
BY Bayrak ◽  
...  
2018 ◽  
Vol 8 (3) ◽  
pp. 204589401879155 ◽  
Author(s):  
Victor P. Bilan ◽  
Frank Schneider ◽  
Enrico M. Novelli ◽  
Eric E. Kelley ◽  
Sruti Shiva ◽  
...  

Pulmonary hypertension (PH) is emerging as a serious complication associated with hemolytic disorders, and plexiform lesions (PXL) have been reported in patients with sickle cell disease (SCD). We hypothesized that repetitive hemolysis per se induces PH and angioproliferative vasculopathy and evaluated a new mechanism for hemolysis-associated PH (HA-PH) that involves the release of adenosine deaminase (ADA) and purine nucleoside phosphorylase (PNP) from erythrocytes. In healthy rats, repetitive administration of hemolyzed autologous blood (HAB) for 10 days produced reversible pulmonary parenchymal injury and vascular remodeling and PH. Moreover, the combination of a single dose of Sugen-5416 (SU, 200 mg/kg) and 10-day HAB treatment resulted in severe and progressive obliterative PH and formation of PXL (Day 26, right ventricular peak systolic pressure (mmHg): 26.1 ± 1.1, 41.5 ± 0.5 and 85.1 ± 5.9 in untreated, HAB treated and SU+HAB treated rats, respectively). In rats, repetitive administration of HAB increased plasma ADA activity and reduced urinary adenosine levels. Similarly, SCD patients had higher plasma ADA and PNP activity and accelerated adenosine, inosine, and guanosine metabolism than healthy controls. Our study provides evidence that hemolysis per se leads to the development of angioproliferative PH. We also report the development of a rat model of HA-PH that closely mimics pulmonary vasculopathy seen in patients with HA-PH. Finally, this study suggests that in hemolytic diseases released ADA and PNP may increase the risk of PH, likely by abolishing the vasoprotective effects of adenosine, inosine and guanosine. Further characterization of this new rat model of hemolysis-induced angioproliferative PH and additional studies of the role of purines metabolism in HA-PH are warranted.


2005 ◽  
Vol 288 (6) ◽  
pp. L1162-L1170 ◽  
Author(s):  
Robert P. Jankov ◽  
Crystal Kantores ◽  
Rosetta Belcastro ◽  
Soojin Yi ◽  
Ross A. Ridsdale ◽  
...  

Newborn rats exposed to 60% O2 for 14 days develop endothelin (ET)-1-dependent pulmonary hypertension with vascular remodeling, characterized by increased smooth muscle cell (SMC) proliferation and medial thickening of pulmonary resistance arteries. Using immunohistochemistry and Western blot analyses, we examined the effect of exposure to 60% O2 on expression in the lung of receptors for the platelet-derived growth factors (PDGF), which are implicated in the pathogenesis of arterial smooth muscle hyperplasia. We observed a marked O2-induced upregulation of PDGF-α and -β receptors (PDGF-αR and -βR) on arterial smooth muscle. This led us to examine pulmonary vascular PDGF receptor expression in 60% O2-exposed rats given SB-217242, a combined ET receptor antagonist, which we found prevented the O2-induced upregulation of PDGF-βR, but not PDGF-αR, on arterial smooth muscle. PDGF-BB, a major PDGF-βR ligand, was found to be a potent in vitro inducer of hyperplasia and DNA synthesis in cultured pulmonary artery SMC from infant rats. A critical role for PDGF-βR ligands in arterial SMC proliferation was confirmed in vivo using a truncated soluble PDGF-βR intervention, which attenuated SMC proliferation induced by exposure to 60% O2. Collectively, these data are consistent with a major role for PDGF-βR-mediated SMC proliferation, acting downstream of increased ET-1 in a newborn rat model of 60% O2-induced pulmonary hypertension.


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