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Renin-Angiotensin-Aldosterone System (RAAS) and Hypothalamic-Pituitary-Adrenal Axis (HPAA) in Critically Ill Foals

Dembek, Katarzyna Agnieszka
http://rave.ohiolink.edu/etdc/view?acc_num=osu1337797078

Abstract Details

2012, Master of Science, Ohio State University, Veterinary Clinical Sciences.
Sepsis is a major cause of morbidity and mortality in neonatal foals. Dysfunction of the hypothalamic-pituitary-adrenal axis (HPAA), manifested as relative adrenal insufficiency (RAI), has been associated with sepsis in newborn foals. Information on the renin-angiotensin-aldosterone system (RAAS) is minimal in healthy or sick foals. The HPAA and RAAS are interactive systems, and a relationship between RAAS activation and RAI is well documented in critically ill children, but limited information exists in septic foals. We hypothesized that in critically ill septic newborn foals the RAAS and HPAA will be activated by systemic inflammation and hypoperfusion and the degree of activation will be associated with severity of sepsis and mortality. For this project, 167 (study 1) and 182 (study 2) sick and healthy foals of less than 7 days of age were included. Blood samples were collected on admission from septic (sepsis score >12), sick non-septic (SNS), and healthy foals. Blood concentrations of cortisol, aldosterone, angiotensin-II (ANG-II), corticotropin-releasing hormone (CRH), arginine vasopressin (AVP), adrenocorticotropic hormone (ACTH) and plasma renin activity were determined by immunoassays. Aldosterone, ANG-II, ACTH and cortisol concentrations were higher in septic compared to healthy foals (P<0.05). AVP was higher and CRH was lower in septic than healthy foals. Septic foals had higher ACTH/aldosterone and ACTH/cortisol ratios than healthy foals (P<0.05). No differences in plasma renin activity were found. Sepsis activates RAAS and HPAA in newborn foals. RAAS activation in critically ill foals is characterized by increased aldosterone and ANG-II concentrations. Low CRH concentrations in septic foals were an unexpected finding. We propose that AVP (not CRH) is the main ACTH releasing-hormone in critically ill foals. Septic foals demonstrated adrenocortical exhaustion with high ACTH/cortisol and ACTH/aldosterone ratios, indicating that RAI is not restricted to the zona fasciculata, but also involves the zona glomerulosa.
Ramiro Toribio (Advisor)
Catherine Kohn (Committee Member)
Samuel Hurcombe (Committee Member)
71 p.
Biology; Endocrinology; Veterinary Services
sepsis; foal; adrenal insufficiency; aldosterone;

Recommended Citations

Citations

  • Dembek, K. A. (2012). Renin-Angiotensin-Aldosterone System (RAAS) and Hypothalamic-Pituitary-Adrenal Axis (HPAA) in Critically Ill Foals [Master's thesis, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1337797078

    APA Style (7th edition)

  • Dembek, Katarzyna. Renin-Angiotensin-Aldosterone System (RAAS) and Hypothalamic-Pituitary-Adrenal Axis (HPAA) in Critically Ill Foals. 2012. Ohio State University, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1337797078.

    MLA Style (8th edition)

  • Dembek, Katarzyna. "Renin-Angiotensin-Aldosterone System (RAAS) and Hypothalamic-Pituitary-Adrenal Axis (HPAA) in Critically Ill Foals." Master's thesis, Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1337797078

    Chicago Manual of Style (17th edition)

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This open access ETD is published by The Ohio State University and OhioLINK.