Background: Amyotrophic Lateral sclerosis (ALS) is associated with a significant distress, being linked to changes in hypothalamic-pituitary-adrenal axis activity. A loss of cortisol circadian rhythmicity in ALS patients was suggested,while more recently an increased plasma cortisol level in the disease has been reported.
Objective: To assay the circadian plasma cortisol level in ALS and to study its relationship with the clinical phenotype and the rate of disease progression.
Patients and methods: 135 ALS patients (Bulbar, 33; Spinal, 102;M/F=1.73) and 110 controls (not affected by neurological or psychiatric disorders, free of drugs; M/F=1.75) were recruited. Disease progression was scored with ΔFS.Morning and evening plasma cortisol levels (μg/dl)were assayed from fasting ALS patients and controls using Elecsys® Cortisol Immunoassay System.
Results: We found that the morning level of cortisol in ALS patients was higher than controls (morning: ALS, 15.2[11.5-18.9] vs Controls, 11.4 [8.8 -14.3], p b 0.001; evening: ALS, 7.5[4.7–11.8] vs Controls, 7.9[5.4–10.0], p=0.6).Furthermore, the hormone's level was higher in the spinal-onset group (Spinal, 15.9[11.9–19.0] vs Bulbar,13.5[10.1–18.6] vs controls, 11.4[8.8–14.3], p b 0.001) and in patients with intermediate/rapid disease course.
Conclusions: Morning plasma cortisol level is increased in ALS, mainly in spinal-onset patients and in those with intermediate/rapidly progressing disease. The plasmatic changes of the steroid hormone appear however too small to make it a sensitive biochemical marker in this severe neurodegenerative disease.
Keywords: ALS; ALSFRS-R; Biomarker; Cortisol; Disease progression.