Pulmonary microvascular remodeling in chronic thrombo-embolic pulmonary hypertension.
Am J Physiol Lung Cell Mol Physiol
; 315(6): L951-L964, 2018 12 01.
Article
en En
| MEDLINE
| ID: mdl-30260284
ABSTRACT
Pulmonary vascular remodeling in pulmonary arterial hypertension involves perturbations in the nitric oxide (NO) and endothelin-1 (ET-1) pathways. However, the implications of pulmonary vascular remodeling and these pathways remain unclear in chronic thrombo-embolic pulmonary hypertension (CTEPH). The objective of the present study was to characterize changes in microvascular morphology and function, focussing on the ET-1 and NO pathways, in a CTEPH swine model. Swine were chronically instrumented and received up to five pulmonary embolizations by microsphere infusion, whereas endothelial dysfunction was induced by daily administration of the endothelial NO synthase inhibitor Nω-nitro-l-arginine methyl ester until 2 wk before the end of study. Swine were subjected to exercise, and the pulmonary vasculature was investigated by hemodynamic, histological, quantitative PCR, and myograph experiments. In swine with CTEPH, the increased right-ventricular afterload, decreased cardiac index, and mild ventilation-perfusion-mismatch were exacerbated during exercise. Pulmonary microvascular remodeling was evidenced by increased muscularization, which was accompanied by an increased maximal vasoconstriction. Although ET-1-induced vasoconstriction was increased in CTEPH pulmonary small arteries, the ET-1 sensitivity was decreased. Moreover, the contribution of the ETA receptor to ET-1 vasoconstriction was increased, whereas the contribution of the ETB receptor was decreased and the contribution of Rho-kinase was lost. A reduction in endogenous NO production was compensated in part by a decreased phosphodiesterase 5 (PDE5) activity resulting in an apparent increased NO sensitivity in CTEPH pulmonary small arteries. These findings suggest that pulmonary microvascular remodeling with a reduced activity of PDE5 and Rho-kinase may contribute to the lack of therapeutic efficacy of PDE5 inhibitors and Rho-kinase inhibitors in CTEPH.
Palabras clave
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Embolia Pulmonar
/
Microvasos
/
Hipertensión Pulmonar
/
Pulmón
Tipo de estudio:
Prognostic_studies
Límite:
Animals
Idioma:
En
Revista:
Am J Physiol Lung Cell Mol Physiol
Asunto de la revista:
BIOLOGIA MOLECULAR
/
FISIOLOGIA
Año:
2018
Tipo del documento:
Article
País de afiliación:
Países Bajos