Cortisol Hair analysisAnalysis of drugs, drug metabolites and endogenous markers in hair provides a non-invasive tool for research and clinical diagnostic purposes. Deposition of drugs and their metabolites in hair during growth allows for retrospective quantification providing a rare apportunity to look into the clinical history of the patient. Cortisol is one such metabolite with a diverse array of uses which has become increasingly appreciated since first recorded. Endogenous cortisol levels are regulated by the hypothalamic-pituitary-adrenal (HPA) axis and influenced by both stress and blood glucose levels.
Cortisol is a glucocorticoid (a class of steroid hormones) and in normal circumstances is released by the cortex of the adrenal glands. Cortisol helps maintain homeostasis in the body and has a wide range of physiological effects including glucose, lipid and protein metabolism, and anti-inflammatory and immunosuppressive effects. Hair cortisol analysis is now widely used at the forefront of research addressing the effects of both acute and chronic stress. Cortisol levels are influenced by a broad range of psychiatric disorders. Stress has been collectively recognized as a premorbid feature associated with several risk factors for numerous chronic disorders.
Hair cortisol content (HCC) has been used extensively to study sociodemographic and psychosocial factors including the effects of war and natural disasters. From a clinical perspective, many disorders affecting the HPA axis including Cushing’s syndrome, irritable bowel syndrome, seizures, and stroke have been studied. Clinically HCC grants us an insightful tool for the measurement of cortisol levels historically over time. This unique feature to retrospectively quantify endogenous metabolites has the potential to significantly decrease time to diagnosis.
Hair samples for cortisol analysis have been generally considered to be stable and able to be stored at room temperature for extended periods of time.
Cortisol levels fluctuate daily based on our circadian rhythm peaking in the morning before coming to a low in the evening at bed time. The circadian nature of cortisol establishes the difficulty of measurement by traditional methods such as saliva, urine, and blood.
Saliva, Urine, and Hair provide acute, short-term, and long-term biomarkers for cortisol. Traditionally Saliva and Urine have been used for the measurement of cortisol with subsequent clinical diagnosis. Where these biomarkers fall short is in the need to daily measurement to determine an average due circadian fluctuation of levels. Acute and Short-term cortisol biomarkers are currently the standard for screening of endocrinological disorders. Hair provides a tool for the determination of a historical average without the need for daily measurement taking going forward over time. In clinical conditions such as cyclical Cushing’s HCC has the potential to eliminate weeks, months and even years of daily measurements. A diagnosis of true cyclicity of Cushing’s requires evidence of at least 3 peaks and 2 troughs in cortisol levels over time. Depending on the nature of a patients condition it may take months to observe these findings by traditional methods. HCC allows for the instantaneous ability to look back in time to make these observations.
The use of HCC as a long term measure of cortisol helps to mitigate the acute effects on endogenous cortisol levels due to alcohol, nicotine, food, glucose levels, exercise, blood oxygen levels, and acute injury .
Procedure of Hair cortisol analysis:
hair samples are usually collected by cutting approximately 3 mm diameter sample of hair at the base of the vertex posterior of the head (The Figure). Samples are then carefully segmented into sections that represent the periods of interest (each 1 cm approximately represent 1 moth period). Individual samples are then placed in glass vials and weighed. In order to maximize the extraction of cortisol from the hair shaft matrix, pulverization of hair is necessary to increase the surface area exposed to the extracting organic solvent. Sweat and sebum contains cortisol that may contaminate measurements and washing normalizes any individual hygienic differences. Two to three washes with isopropanol for 3 minutes each is commonly used followed by air drying. Cortisol is extracted from minced or ground hair using organic solvents (e.g., methanol, acetone). The supernatant is then evaporated in a dry bath under nitrogen stream till complete dryness. The dry residues are then re-suspended in 150-250 μL of phosphate buffered saline (PBS, pH 8.0) or distilled water and vortexed until complete dissolving is achieved. Samples can then be kept frozen until measurement. Competitive solid-phase enzyme-linked immunosorbent assay (ELISA, also luminescence immunoassay, LIA, and radio immunoassay, RIA) or liquid chromatography-mass spectroscopy (LC-MS) are all used to measure the concentration of cortisol in hair extracts. Measurements are expressed as ng per mg of hair.
Please see SHIPPING INSTRUCTIONS for how to send hair samples for analysis.