Serum free cortisol fraction in healthy and septic neonatal foals.
Abstract: Relative cortisol insufficiency occurs in septic foals and impacts survival. Serum free (biologically available) cortisol concentration might be a better indicator of physiologic cortisol status than serum total cortisol concentration in foals. Objective: In septic foals, (1) low free cortisol concentration correlates with disease severity and survival and (2) predicts disease severity and outcome better than total cortisol concentration. Methods: Fifty-one septic foals; 11 healthy foals; 6 healthy horses. Methods: In this prospective clinical study, foals meeting criteria for sepsis at admission were enrolled. University-owned animals served as healthy controls. Basal and cosyntropin-stimulated total cortisol concentration and percent free cortisol (% free cortisol) were determined by chemiluminescent immunoassay and ultrafiltration/ligand-binding methods, respectively. Group data were compared by ANOVA, Mann-Whitney U-tests, and receiver operator characteristic curves. Significance was set at P < .05. Results: Basal % free cortisol was highest in healthy foals at birth (58 ± 8% mean ± SD), and was higher (P ≤ .004) in healthy foals of all ages (33 ± 6 to 58 ± 8%) than in adult horses (7 ± 3%). Cosyntropin-stimulated total and free cortisol concentrations were lower (P ≤ .03) in foals with shock (total = 6.2 ± 8.1 μg/dL; free = 3.5 ± 4.8 μg/dL versus total = 10.8 ± 6.0 μg/dL; free = 6.9 ± 3.3 μg/dL in foals without shock) and in nonsurvivors (total = 3.8 ± 6.9 μg/dL; free = 1.9 ± 3.9 μg/dL versus total = 9.1 ± 7.7 μg/dL; free = 5.5 ± 4.4 μg/dL in survivors). Free cortisol was no better than total cortisol at predicting disease severity or outcome in septic foals. Conclusions: Serum free cortisol is impacted by age and illness in the horse. There is no advantage to measuring free over total cortisol in septic foals.
Copyright © 2011 by the American College of Veterinary Internal Medicine.
Publication Date: 2011-01-31 PubMed ID: 21281351DOI: 10.1111/j.1939-1676.2010.0667.xGoogle Scholar: Lookup
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- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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The research study is aimed at examining the role of cortisol, specifically free (biologically available) cortisol, in septic foals and its correlation with disease severity and survival rate. The results indicated that the free cortisol levels in septic foals were not more predictive of disease severity or outcome than total cortisol levels.
Research Methodology
- In this study, prospective clinical methods were used and included a sample of fifty-one septic foals and eleven healthy foals. Six healthy adult horses were also part of the study to serve as controls.
- The criteria for a foal to be considered septic (and thus eligible for the study) were determined at admission.
- The analysis of cortisol levels involved determining the basal (natural, resting level) and cosyntropin-stimulated (artificially induced for testing purposes) total cortisol concentration and calculating the percentage of free cortisol.
- The researchers used chemiluminescent immunoassay and ultrafiltration/ligand-binding methods to measure cortisol levels.
- To process and analyze the data, statistical tests such as ANOVA, Mann-Whitney U-tests, and receiver operator characteristic curves were used. A significance level of P < .05 was used.
Key Findings
- Baseline free cortisol levels were highest in healthy foals at birth (58 ± 8% mean ± SD), and were generally higher in healthy foals than in adult horses (33 ± 6 to 58 ± 8% for foals, compared to 7 ± 3% for adults).
- Both total and free cortisol concentrations (induced with cosyntropin) were found to be lower in foals with shock—as well as in those that did not survive the sepsis—compared to healthy foals or septic foals that survived.
- Against the initial hypothesis, free cortisol was not more indicative of disease severity or outcome in septic foals than total cortisol.
Conclusion
- The results of the study concluded that free cortisol levels in horses are influenced by age and illness.
- Notably, the study found that measuring free cortisol levels does not provide any advantage over measuring total cortisol levels in predicting disease severity or survival in septic foals.
Cite This Article
APA
Hart KA, Barton MH, Ferguson DC, Berghaus R, Slovis NM, Heusner GL, Hurley DJ.
(2011).
Serum free cortisol fraction in healthy and septic neonatal foals.
J Vet Intern Med, 25(2), 345-355.
https://doi.org/10.1111/j.1939-1676.2010.0667.x Publication
Researcher Affiliations
- Department of Large Animal Medicine, College of Veterinary Medicine, University of Georgia, Athens, GA, USA. khart4@uga.edu
MeSH Terms
- Age Factors
- Animals
- Animals, Newborn / blood
- Case-Control Studies
- Female
- Horse Diseases / blood
- Horse Diseases / mortality
- Horses
- Hydrocortisone / blood
- Male
- Predictive Value of Tests
- Prospective Studies
- ROC Curve
- Sepsis / blood
- Sepsis / mortality
- Sepsis / veterinary
- Severity of Illness Index
Citations
This article has been cited 8 times.- Swink JM, Rings LM, Snyder HA, McAuley RC, Burns TA, Dembek KA, Gilsenan WF, Browne N, Toribio RE. Dynamics of androgens in healthy and hospitalized newborn foals.. J Vet Intern Med 2021 Jan;35(1):538-549.
- Taylor S. A review of equine sepsis.. Equine Vet Educ 2015 Feb;27(2):99-109.
- Stewart AJ, Hackett E, Bertin FR, Towns TJ. Cortisol and adrenocorticotropic hormone concentrations in horses with systemic inflammatory response syndrome.. J Vet Intern Med 2019 Sep;33(5):2257-2266.
- Aleman M, McCue PM, Chigerwe M, Madigan JE. Plasma concentrations of steroid precursors, steroids, neuroactive steroids, and neurosteroids in healthy neonatal foals from birth to 7 days of age.. J Vet Intern Med 2019 Sep;33(5):2286-2293.
- Morgan RA, Keen JA, Homer N, Nixon M, McKinnon-Garvin AM, Moses-Williams JA, Davis SR, Hadoke PWF, Walker BR. Dysregulation of Cortisol Metabolism in Equine Pituitary Pars Intermedia Dysfunction.. Endocrinology 2018 Nov 1;159(11):3791-3800.
- Schwinn AC, Sauer FJ, Gerber V, Bruckmaier RM, Gross JJ. Free and bound cortisol in plasma and saliva during ACTH challenge in dairy cows and horses.. J Anim Sci 2018 Feb 15;96(1):76-84.
- Hart KA, Wochele DM, Norton NA, McFarlane D, Wooldridge AA, Frank N. Effect of Age, Season, Body Condition, and Endocrine Status on Serum Free Cortisol Fraction and Insulin Concentration in Horses.. J Vet Intern Med 2016 Mar-Apr;30(2):653-63.
- Hart KA, Barton MH. Adrenocortical insufficiency in horses and foals.. Vet Clin North Am Equine Pract 2011 Apr;27(1):19-34.
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