A novel method for assessing chronic cortisol concentrations in dogs using the nail as a source

Area of Science:

• Veterinary Medicine
• Endocrinology
• Analytical Chemistry

Background:

• Cortisol, a key glucocorticoid, is crucial for assessing adrenal function and mental health.
• Current cortisol measurement methods reflect short-term stress, limiting diagnostic insights.
• A need exists for a more stable, integrated measure of cortisol secretion in canines.

Purpose of the Study:

• To develop and validate a novel method for quantifying cortisol in dog nails.
• To assess the potential of nail cortisol as a long-term biomarker for canine stress and adrenal health.
• To compare nail cortisol levels with established methods like hair cortisol analysis.

Main Methods:

• Solid phase extraction (SPE) was employed for cortisol extraction from canine nail samples.
• Enzyme-linked immunosorbent assay (ELISA) was utilized for cortisol quantification.
• Method validation included assessments of accuracy, precision, and repeatability.

Main Results:

• The novel nail cortisol assay demonstrated good accuracy (r = 0.836), precision (CV = 15.1%), and repeatability (CV = 14.4%).
• Nail cortisol concentrations showed a significant positive correlation with hair cortisol levels (r = 0.736).
• No significant differences in nail cortisol were observed based on dog sex, breed, age, or weight, though sample size was limited.

Conclusions:

• Canine nail cortisol analysis offers a reliable method for assessing integrated cortisol secretion over nail growth periods.
• This method holds promise as a diagnostic tool for long-term stress and adrenal disorders in dogs.
• Nail cortisol provides a valuable, less variable alternative to short-term stress indicators.