Results of this work were partially presented as an oral abstract at the 2012 American College of Veterinary Internal Medicine (ACVIM) Forum, New Orleans, LA.
Renin-Angiotensin-Aldosterone System and Hypothalamic-Pituitary-Adrenal Axis in Hospitalized Newborn Foals
Article first published online: 11 FEB 2013
Copyright © 2013 by the American College of Veterinary Internal Medicine
Journal of Veterinary Internal Medicine
Volume 27, Issue 2, pages 331–338, March/April 2013
How to Cite
Dembek, K.A., Onasch, K., Hurcombe, S.D.A., MacGillivray, K.C., Slovis, N.M., Barr, B.S., Reed, S.M. and Toribio, R.E. (2013), Renin-Angiotensin-Aldosterone System and Hypothalamic-Pituitary-Adrenal Axis in Hospitalized Newborn Foals. Journal of Veterinary Internal Medicine, 27: 331–338. doi: 10.1111/jvim.12043
- Issue published online: 15 MAR 2013
- Article first published online: 11 FEB 2013
- Manuscript Accepted: 20 DEC 2012
- Manuscript Revised: 3 DEC 2012
- Manuscript Received: 12 APR 2012
- United States Department of Agriculture
- OSU College of Veterinary Medicine
- Adrenal insufficiency;
The renin-angiotensin-aldosterone system (RAAS) and hypothalamic-pituitary-adrenal axis (HPAA) and their interactions during illness and hypoperfusion are important to maintain organ function. HPAA dysfunction and relative adrenal insufficiency (RAI) are common in septic foals. Information is lacking on the RAAS and mineralocorticoid response in the context of RAI in newborn sick foals.
To investigate the RAAS, as well as HPAA factors that interact with the RAAS, in hospitalized foals, and to determine their association with clinical findings. We hypothesized that critical illness in newborn foals results in RAAS activation, and that inappropriately low aldosterone concentrations are part of the RAI syndrome of critically ill foals.
A total of 167 foals ≤3 days of age: 133 hospitalized (74 septic, 59 sick nonseptic) and 34 healthy foals.
Prospective, multicenter, cross-sectional study. Blood samples were collected on admission. Plasma renin activity (PRA) and angiotensin-II (ANG-II), aldosterone, ACTH, and cortisol concentrations were measured in all foals.
ANG-II, aldosterone, ACTH, and cortisol concentrations as well as ACTH/aldosterone and ACTH/cortisol ratios were higher in septic foals compared with healthy foals (P < .05). No difference in PRA between groups was found. High serum potassium and low serum chloride concentrations were associated with hyperaldosteronemia in septic foals.
Conclusions and Clinical Importance
RAAS activation in critically ill foals is characterized by increased ANG-II and aldosterone concentrations. Inappropriately low cortisol and aldosterone concentrations defined as high ACTH/cortisol and ACTH/aldosterone ratios in septic foals suggest that RAI is not restricted to the zona fasciculata in critically ill newborn foals.