Association of adrenocorticotrophin and cortisol concentrations with peripheral blood leukocyte cytokine gene expression in septic and nonseptic neonatal foals.

This research investigates the relationship between hormones of the Hypothalamic-Pituitary-Adrenal (HPA) axis, specifically adrenocorticotrophin (ACTH) and cortisol, and the expression of cytokine genes in the white blood cells of hospitalized newborn foals, both septic and non-septic. It reveals that sepsis influences the secretion of HPA hormones and cytokine expression, with a significant positive association found between ACTH and the proinflammatory cytokine IL-6.

Objective and Methodology

• As suggested by the abstract, the purpose of this study was twofold. Firstly, it intended to trace the changes over time in ACTH and cortisol concentrations, and the expression of cytokine genes in the white blood cells of both septic and non-septic hospitalized foals. Secondly, it aimed to investigate any correlations between these HPA axis hormones and the expression of cytokine genes in the white blood cells.
• The study involved 15 septic foals and 11 non-septic foals, all of whom were in a hospital setting. The researchers collected blood samples at five separate points following admission: on arrival, and then 24, 48, 72, and 96 hours later. From these samples, they harvested plasma and serum for hormone assays, while using RNA extraction from white blood cells for cytokine gene expression analysis.
• Specifically, plasma concentrations of the hormone ACTH were measured, as were serum cortisol concentrations, using a procedure known as a radioimmunoassay. The expression of the cytokine genes IL-1β, IL-6, IL-8, IL-10, and TNF-α in the white blood cells was determined via RT-PCR.

Research Findings

• The research findings revealed that cortisol concentrations were significantly higher in the foals upon admission than at any other time. This suggests that stress, potentially due to the illness or the hospitalization itself, may have elevated cortisol levels initially.
• The expressions of genes IL-8 and IL-10, which are both cytokines, were consistently lower at all measurement points in septic foals than in non-septic foals.
• A significant finding was the detection of a positive association between ACTH levels and the expression of the proinflammatory cytokine IL-6 in septic foals. This suggests a potential link between the body’s stress response (signaled by ACTH) and inflammation (signaled by IL-6) during sepsis in neonatal foals.
• Overall, the research indicates that sepsis in newborn foals influences the secretion of hormones from the HPA axis and the expression of proinflammatory cytokines, potentially underlining a connection between stress response and immune response in these animals.

Conclusions and Further Study

• In conclusion, sepsis in newborn foals appears to affect the endocrine and immune systems, specifically the hormones related to the HPA axis and cytokine expression in white blood cells.
• Researchers posit that more extensive studies will be needed to understand the clinical importance of these findings fully.