Alterations in lung arginine metabolism in lambs with pulmonary hypertension associated with increased pulmonary blood flow.
Previous studies demonstrate impaired nitric oxide (NO) signaling in children and animal models with congenital heart defects and increased pulmonary blood flow. However, the molecular mechanisms underlying these alterations remain incompletely understood. The purpose of this study was to determine if early changes in arginine metabolic pathways could play a role in the reduced NO signaling demonstrated in our lamb model of congenital heart disease with increased pulmonary blood flow (Shunt lambs). The activities of the arginine recycling enzymes, argininosuccinate synthetase (ASS) and argininosuccinate lyase (ASL) were both decreased in lung tissues of Shunt lambs while arginase activity was increased. Associated with these alterations, lung L-arginine levels were decreased. These changes correlated with an increase in NO synthase-derived reactive oxygen species (ROS) generation. This study provides further insights into the molecular mechanisms leading to decreased NO signaling in Shunt lambs and suggests that altered arginine metabolism may play a role in the development of the endothelial dysfunction associated with pulmonary hypertension secondary to increased pulmonary blood flow.
Sharma
Shruti
S
Vascular Biology Center, 1459 Laney Walker Boulevard, CB3201B, Medical College of Georgia, Augusta, GA 30912, USA.
Kumar
Sanjiv
S
Sud
Neetu
N
Wiseman
Dean A
DA
Tian
Jing
J
Rehmani
Imran
I
Datar
Sanjeev
S
Oishi
Peter
P
Fratz
Sohrab
S
Venema
Richard C
RC
Fineman
Jeffrey R
JR
Black
Stephen M
SM
D000595:Amino Acid Sequence; D000596:Amino Acids / Q000097:blood; D000818:Animals; D001119:Arginase / Q000378:metabolism; D001120:Arginine / Q000378:metabolism*; D001794:Blood Pressure; D005260:Female; D006976:Hypertension, Pulmonary / Q000378:metabolism*; D008168:Lung / Q000378:metabolism*; D008969:Molecular Sequence Data; D009569:Nitric Oxide / Q000502:physiology; D011247:Pregnancy; D011652:Pulmonary Circulation; D012756:Sheep
D000596:Amino Acids; D009569:Nitric Oxide; D001120:Arginine; D001119:Arginase