Regression of flow-induced pulmonary arterial vasculopathy after flow correction in piglets.
OBJECTIVE
Chronic thromboembolic pulmonary hypertension is due to partial obstruction of the pulmonary arterial bed and may resolve after pulmonary thromboendarterectomy. Persistent pulmonary hypertension, the main complication after pulmonary thromboendarterectomy, may reflect vessel alterations induced by high flow in unobstructed lung territories. The aim of this study was to determine whether correcting high flow led to reversal of the vasculopathy in piglets.


METHODS
The effects of high pulmonary blood flow were investigated 5 weeks after creation of an aortopulmonary shunt (n = 10), and reversibility of vessel disease was evaluated at 1 week (n = 10) and 5 weeks after shunt closure (n = 10), compared to sham-operated animals (n = 10). Hemodynamic variables, pulmonary artery reactivity, and morphometry were recorded. We also investigated the endothelin, angiopoietin, and nitric oxide synthase pathways.


RESULTS
High flow increased medial thickness in distal pulmonary arteries (55.6% +/- 1.2% vs 35.9% +/- 0.8%; P < .0001) owing to an increase of smooth muscle cell proliferation (proliferating cell nuclear antigen labeling). The endothelium-dependent relaxation was altered (P < .05). This phenomenon was associated to an overexpression of endothelin-1, endothelin-A, angiopoietin 1, angiopoietin 2, and Tie-2 (P < .05). After 1 week of shunt closure, all overexpressed genes returned to control values, the proliferation of smooth muscle cells stopped, and smooth muscle cell apoptosis increased (terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling), preceding the normalization of the wall thickness hypertrophy and the pulmonary artery vasoreactivity observed at 5 weeks after shunt closure.


CONCLUSIONS
These results demonstrate that endothelin-1 and angiopoietin pathways are involved in vasculopathy development and may be important therapeutic targets for preventing persistent pulmonary hypertension after pulmonary thromboendarterectomy.
Mercier
Olaf
O
Laboratoire de Chirurgie Expérimentale UPRES-EA 2705, Uninersité Paris XI Hôpital Marie Lannelongue, Le Plessis-Robinson, France. o.mercier@ccml.fr
Sage
Edouard
E
de Perrot
Marc
M
Tu
Ly
L
Marcos
Elisabeth
E
Decante
Benoît
B
Baudet
Bruno
B
Hervé
Philippe
P
Dartevelle
Philippe
P
Eddahibi
Saadia
S
Fadel
Elie
E
D000109:Acetylcholine / Q000494:pharmacology; D042683:Angiopoietin-1 / Q000378:metabolism; D000818:Animals; D017209:Apoptosis; D049109:Cell Proliferation; D003094:Collagen / Q000378:metabolism; D054706:Cyclic Nucleotide Phosphodiesterases, Type 5 / Q000378:metabolism; D004691:Endarterectomy; D019332:Endothelin-1 / Q000378:metabolism / Q000494:pharmacology; D006976:Hypertension, Pulmonary / Q000209:etiology / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology*; D008168:Lung / Q000378:metabolism / Q000473:pathology; D009131:Muscle, Smooth, Vascular / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology; D019001:Nitric Oxide Synthase / Q000378:metabolism; D011651:Pulmonary Artery / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology; D011652:Pulmonary Circulation; D011655:Pulmonary Embolism / Q000150:complications / Q000601:surgery*; D042787:Receptor, TIE-2 / Q000378:metabolism; D017466:Receptors, Endothelin / Q000378:metabolism; D017540:Tunica Media / Q000473:pathology; D014661:Vasoconstriction / Q000187:drug effects; D014664:Vasodilation / Q000187:drug effects
D042683:Angiopoietin-1; D019332:Endothelin-1; D017466:Receptors, Endothelin; D003094:Collagen; D019001:Nitric Oxide Synthase; D042787:Receptor, TIE-2; D054706:Cyclic Nucleotide Phosphodiesterases, Type 5; D000109:Acetylcholine