Budesonide, but not dexamethasone, blunted the response of aldosterone to renin elevation by suppressing angiotensin converting enzyme upon high-altitude exposure.
BACKGROUND
Inhaled budesonide is a novel approach to prevent acute mountain sickness (AMS). However, its mechanism is not completely understood. We aimed to investigate the effects of budesonide and dexamethasone on renin-angiotensin-aldosterone system in AMS prevention.


METHODS
Data were obtained from a randomised controlled trial including 138 participants. The participants were randomly assigned to receive budesonide, dexamethasone or placebo as prophylaxis before they travelled to 3450 m altitude from 400 m by car. Their plasma concentrations of renin, angiotensin-converting enzyme (ACE) and aldosterone were measured at both altitudes.


RESULTS
All parameters were comparable among the three groups at 400 m. After high-altitude exposure of 3450, renin in all groups increased significantly; the ACE, aldosterone concentrations, as well as the aldosterone/renin ratio, rose markedly in the dexamethasone and placebo groups but not in the budesonide group. Moreover, the aldosterone/renin ratio correlated closely with ACE concentration.


CONCLUSIONS
Upon acute high-altitude exposure, budesonide, but not dexamethasone, blunted the response of aldosterone to renin elevation by suppressing angiotensin converting enzyme.
Institute of Cardiovascular Science, Third Military Medical University, China.
Hui-Jie
HJ
Li
Institute of Cardiovascular Science, Third Military Medical University, China Department of Cardiovascular Science, The General Hospital of the People's Liberation Army (PLA) Rocket Force, China.
Cheng-Rong
CR
Zheng
Institute of Cardiovascular Science, Third Military Medical University, China PLA Institute of Cardiovascular Disease, China.
Guo-Zhu
GZ
Chen
Institute of Cardiovascular Science, Third Military Medical University, China PLA Institute of Cardiovascular Disease, China.
Jun
J
Qin
Institute of Cardiovascular Science, Third Military Medical University, China PLA Institute of Cardiovascular Disease, China.
Ji-Hang
JH
Zhang
Institute of Cardiovascular Science, Third Military Medical University, China PLA Institute of Cardiovascular Disease, China.
Jie
J
Yu
Institute of Cardiovascular Science, Third Military Medical University, China.
En-Hao
EH
Zhang
Institute of Cardiovascular Science, Third Military Medical University, China PLA Institute of Cardiovascular Disease, China huanglan260@126.com.
Lan
L
Huang
D000450:Aldosterone / Q000494:pharmacology / Q000627:therapeutic use*; D000531:Altitude; D000532:Altitude Sickness / Q000097:blood* / Q000188:drug therapy*; D019819:Budesonide / Q000494:pharmacology / Q000627:therapeutic use*; D003907:Dexamethasone / Q000494:pharmacology / Q000627:therapeutic use*; D006801:Humans; D007703:Peptidyl-Dipeptidase A / Q000378:metabolism*; D012083:Renin / Q000097:blood*; D012084:Renin-Angiotensin System / Q000187:drug effects
D000450:Aldosterone; D019819:Budesonide; D003907:Dexamethasone; C488034:ACE protein, human; D007703:Peptidyl-Dipeptidase A; D012083:Renin
Acute mountain sickness; angiotensin-converting enzyme; budesonide; dexamethasone; renin–angiotensin–aldosterone system