Related Experiment Video
Updated: Jun 11, 2026
A Novel and Translational Rat Model of Concussion Combining Force and Rotation with In Vivo Cerebral Microdialysis
Published on: July 12, 2019
Loss of cortisol circadian rhythm in patients with traumatic brain injury: a microdialysis evaluation
Juan Antonio Llompart-Pou1, Gerardo Pérez, Joan María Raurich
1Servei de Medicina Intensiva, Hospital Universitari Son Dureta, Andrea Doria 55, 07014, Palma de Mallorca, Illes Balears, Spain. juanantonio.llompart@ssib.es
Background:
Traumatic brain injury (TBI) is commonly associated with disturbances of the hypothalamic-pituitary-adrenal axis secretion. Cerebral microdialysis techniques have been recently applied to measure brain interstitial cortisol levels.
Methods:
We evaluated for the first time the circadian rhythm of cortisol secretion at 08:00, 16:00, and 24:00 h in the acute phase of TBI by determination of total serum and brain interstitial cortisol levels (microdialysis samples) in 10 patients with TBI. Non-parametric Friedman's two way analysis of variance test was used.
Results:
Mean age was 29.8 ± 13.6 years. Median Glasgow Coma Scale score after resuscitation was 5 (range 3-10). No differences were found in total serum (P = 0.26) and brain interstitial cortisol (P = 0.77) in the whole sample. Intraindividual analysis showed that circadian variability was lost in all patients, both in serum and brain interstitial cortisol samples in the acute phase after TBI.
Conclusion:
In our series, circadian variability of cortisol evaluated by serum and cerebral microdialysis samples seems to be lost in TBI patients.
Related Concept Videos
01:15Chronopharmacokinetics: Circadian Rhythms and Influence on Drug Response
The time of drug administration is an important factor to consider, as it can influence the toxic dose of a drug. For example, a study conducted by Prins et al. in 1997 examined the effects of the timing of...
02:19Circadian Rhythms and Gene Regulation
01:28Traumatic Brain Injury l: Introduction