Relationship between cortisol, Interleukin-6 and homocysteine in Alzheimer’s disease

Abstract EN

Objective: Alzheimer’s disease (AD) is characterised by progressive cognitive decline due to neurodegen- eration.

Over activation of the hypothalamic– pituitary–adrenal axis, oxidative stress and inflam- mation potentially damage the neuronal system, affecting cognition.

Aim: This study aimed to assess the relationship between serum cortisol, Interleukin-6 (IL-6) and homocysteine (Hcy) levels in AD.

Methods: Case-Control observational study consist- ing of 71 patients with AD and 70 healthy controls above 60 years of age.

Serum samples were analysed for cortisol, IL-6 and Hcy levels using chemilumines- cence immunoassay (Immulite 1000) technique.

Cognitive functions were measured using the Mini- Mental State Examination (MMSE) Score.

AD subjects were categorised based on the modified Kuppuswamy socioeconomic status scale.

Statistical evaluation was conducted using SPSS Statistics software.

Group data were analysed using a two-tailed Student’s t-test, analysis of variance (ANOVA), the Mann–Whitney U test and Pearson’s correlation test.

Results: Serum cortisol, IL-6 and Hcy levels were significantly increased ( p , 0.01) in AD (cortisol: 19.69 ^ 8.96 ug/dl; IL-6: 10.27 ^ 2.76 pg/ml; Hcy: 23.29 ^ 3.81 mmol/l), as compared with the controls (cortisol: 13.37 ^ 5.59 ug/dl; IL-6: 3.37 ^ 0.79 pg/ml; Hcy: 8.25 ^ 2.36 mmol/l).

MMSE scores in AD were negatively correlated with cortisol, IL-6 and Hcy levels.

Conclusions: Serum cortisol, IL-6 and Hcy levels are independent biomarkers for AD progression.

Hyper- cortisolaemia, hyperhomocysteinemia and inflam- mation play important roles in AD-related cognitive dysfunction and are interlinked.