title: Formation of plexiform lesions in experimental severe pulmonary arterial hypertension.
abstract: BACKGROUND
  The plexiform lesion is the hallmark of severe pulmonary arterial hypertension. However, its genesis and hemodynamic effects are largely unknown because of the limited availability of lung tissue samples from patients with pulmonary arterial hypertension and the lack of appropriate animal models. This study investigated whether rats with severe progressive pulmonary hypertension developed plexiform lesions.
  
  
  RESULTS
  After a single subcutaneous injection of the vascular endothelial growth factor receptor blocker Sugen 5416, rats were exposed to hypoxia for 3 weeks. They were then returned to normoxia for an additional 10 to 11 weeks. Hemodynamic and histological examinations were performed at 13 to 14 weeks after the Sugen 5416 injection. All rats developed pulmonary hypertension (right ventricular systolic pressure approximately 100 mm Hg) and severe pulmonary arteriopathy, including concentric neointimal and complex plexiform-like lesions. There were 2 patterns of complex lesion formation: a lesion forming within the vessel lumen (stalk-like) and another that projected outside the vessel (aneurysm-like). Immunohistochemical analyses showed that these structures had cellular and molecular features closely resembling human plexiform lesions.
  
  
  CONCLUSIONS
  Severe, sustained pulmonary hypertension in a very late stage of the Sugen 5416/hypoxia/normoxia-exposed rat is accompanied by the formation of lesions that are indistinguishable from the pulmonary arteriopathy of human pulmonary arterial hypertension. This unique model provides a new and rigorous approach for investigating the genesis, hemodynamic effects, and reversibility of plexiform and other occlusive lesions in pulmonary arterial hypertension.
authors.affiliation: Department of Pharmacology, Center for Lung Biology, University of South Alabama, AL, USA.
authors.forename: Kohtaro
authors.initials: K
authors.lastname: Abe
authors.forename: Michie
authors.initials: M
authors.lastname: Toba
authors.forename: Abdallah
authors.initials: A
authors.lastname: Alzoubi
authors.forename: Masako
authors.initials: M
authors.lastname: Ito
authors.forename: Karen A
authors.initials: KA
authors.lastname: Fagan
authors.forename: Carlyne D
authors.initials: CD
authors.lastname: Cool
authors.forename: Norbert F
authors.initials: NF
authors.lastname: Voelkel
authors.forename: Ivan F
authors.initials: IF
authors.lastname: McMurtry
authors.forename: Masahiko
authors.initials: M
authors.lastname: Oka
mesh_terms: D000818:Animals; D001158:Arteries / Q000473:pathology; D004195:Disease Models, Animal; D006976:Hypertension, Pulmonary / Q000209:etiology / Q000473:pathology*; D000860:Hypoxia; D008168:Lung / Q000098:blood supply; D051381:Rats; D042461:Vascular Endothelial Growth Factor A / Q000037:antagonists & inhibitors
chemical_list: D042461:Vascular Endothelial Growth Factor A