Plasma levels of ACTH and cortisol in normal and critically-ill neonatal foals.

This research investigates the levels of Adrenocorticotropic hormone (ACTH) and cortisol in sick and healthy young horses (foals). The objective is to create a better understanding of these hormone levels in relation to foal health, survival, and recovery from illness.

Research Introduction

• The study focuses on the hypothalamic-pituitary-adrenal axis, which is responsible for managing stress in organisms. In human health management, lower than expected levels of cortisol in response to severe illness or stress (relative adrenal insufficiency) is often observed.
• Previous studies have suggested that septicemic foals (foals suffering from blood poisoning, typically from bacterial infection) exhibit higher levels of ACTH and cortisol than healthy foals. Furthermore, a high ACTH/cortisol ratio (A/C ratio) has been associated with a higher likelihood of death in neonatal foals.
• The purpose of this study was to compare hormone levels and ratios in healthy foals and sick foals, to evaluate their potential prognostic value.

Materials and Methods

• The research involved 31 foals less than 5 days old from the University of Bologna’s Veterinary Teaching Hospital. The foals were sorted into four groups, consisting of healthy foals, foals recovering from sepsis, foals that did not survive sepsis, and those suffering from Perinatal Asphyxia Syndrome.
• The plasma ACTH and cortisol levels of foals in each group were measured and compared at different points in time.
• Other health indicators were also evaluated, including Apgar scores, blood gas analysis, clinical examination results, hematobiochemical profiles, IgG serum concentrations, blood pressure, and sepsis scores, to correlate with hormone levels.

Results

• The study found significantly higher levels of ACTH and cortisol in septic (sick) foals than in healthy equals. The hormone levels were even higher in septic foals that did not survive the illness compared to those that did.
• The research also discovered a significant difference in cortisol levels at the start and end of 24 hours in healthy and recovering foals.
• The A/C ratio showed significant differences between healthy foals and sick foals, with those showing symptoms of sepsis having higher ratios.

Discussion

• The findings support those of earlier studies showing high levels of ACTH and cortisol in septicemic foals. It also highlights the potential for the A/C ratio to serve as a prognostic indicator, helping predict the likelihood of survival in sick foals.
• The researchers suggest that the A/C ratio may be more useful than the absolute values of each hormone, especially in clinical practices where a corticotrophin stimulation test may not be readily available.
• While the study provides valuable insights into the correlation between hormone levels and illness in newborn foals, more research is needed to fully understand this relationship and its potential use in therapeutic interventions.