Hepatocyte growth factor suppresses vascular medial hyperplasia and matrix accumulation in advanced pulmonary hypertension of rats.
BACKGROUND
Pulmonary hypertension (PH) is a progressive disease characterized by raised pulmonary vascular resistance, thought to be curable only through lung transplantation. Pathophysiologically, proliferation of pulmonary artery smooth muscle cells triggers pulmonary arterial stenosis and/or regurgitation, especially in advanced PH.


RESULTS
Using a rat model of advanced pulmonary vascular disease produced by injecting monocrotaline, we show that hepatocyte growth factor (HGF) targets pulmonary arterioles and blocks the progression of PH. In these rats, endogenous HGF production was dramatically downregulated during developing experimental PH, but c-Met/HGF receptor was abundant in the medial layers of pulmonary arterioles. HGF gene transfection 2 weeks after the monocrotaline injection resulted in milder medial hyperplasia in lung arterioles and inhibited overgrowth of pulmonary artery smooth muscle cells. Notably, exogenous HGF reduced lung expression levels of endothelin-1 and transforming growth factor-beta, which are critically involved in PH-linked fibrogenic events. Overall, medial wall thickening of pulmonary arteries was almost completely prevented by HGF, and the total collagen deposition in the lung decreased; both effects contributed to the suppression of pulmonary artery hypertension.


CONCLUSIONS
Our results suggest that the loss of endogenous HGF may be a feature of the pathogenesis of PH and that HGF supplementation may minimize pathological lung conditions, even advanced PH.
Ono
Masamichi
M
Division of Cardiovascular Surgery, Department of Surgery, Osaka University Graduate School of Medicine, Osaka, Japan.
Sawa
Yoshiki
Y
Mizuno
Shinya
S
Fukushima
Norihida
N
Ichikawa
Hajime
H
Bessho
Kazuhiko
K
Nakamura
Toshikazu
T
Matsuda
Hikaru
H
D000818:Animals; D001160:Arterioles / Q000473:pathology; D003094:Collagen / Q000032:analysis; D019332:Endothelin-1 / Q000096:biosynthesis / Q000235:genetics; D005109:Extracellular Matrix / Q000378:metabolism*; D005355:Fibrosis; D015316:Genetic Therapy; D017228:Hepatocyte Growth Factor / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D006801:Humans; D006965:Hyperplasia; D006976:Hypertension, Pulmonary / Q000139:chemically induced / Q000378:metabolism / Q000473:pathology / Q000628:therapy*; D008297:Male; D016686:Monocrotaline / Q000633:toxicity; D009131:Muscle, Smooth, Vascular / Q000473:pathology; D032389:Myocytes, Smooth Muscle / Q000473:pathology; D019859:Proto-Oncogene Proteins c-met / Q000096:biosynthesis / Q000235:genetics; D051381:Rats; D017208:Rats, Wistar; D014162:Transfection; D016212:Transforming Growth Factor beta / Q000096:biosynthesis / Q000235:genetics; D017540:Tunica Media / Q000473:pathology*
D019332:Endothelin-1; D016212:Transforming Growth Factor beta; D017228:Hepatocyte Growth Factor; D016686:Monocrotaline; D003094:Collagen; D019859:Proto-Oncogene Proteins c-met