Relationship between serum oxidative stress and blood brain barrier parameters in patients with major depression

Research emphasises the critical role of blood-brain barrier (BBB) integrity in psychiatric disorders. This study aimed to investigate the relationship between serum Zonula occludens protein - 1 (ZO-1) and serum occludin levels, which are blood brain barrier markers, and serum oxLDL levels, which are known to be associated with oxidative stress and inflammation, in patients with major depression.

The study included 44 drug-naïve patients diagnosed with Major Depressive Disorder (MDD) and 48 healthy controls matched for Body Mass Index (BMI), gender, age. Laboratory data, together with concentrations of Ox-LDL, Occludin, ZO-1, were evaluated. The Hamilton Depression Rating Scale (HADRS) was employed to evaluate the severity of depression in the major depression cohort.

Compared to healthy controls, patients with major depression exhibited significantly lower serum levels of ZO-1 (p = 0.001) and occludin (p = 0.001), while oxLDL levels were significantly higher (p = 0.001). The differences maintained as significant after corrections for age, sex, smoking, and BMI via ANCOVA (all p = 0.001). A positive correlation was identified between ZO-1 and occludin levels (r = .400, p = 0.001), whereas a negative correlation was found between ZO-1 and oxLDL levels (r = -.369, p = 0.001).

This study's findings indicate that serum oxLDL levels, related with oxidative stress and inflammation in the pathogenesis of MDD, may influence the alteration of serum ZO-1 and occludin levels, recognised as indicators of the BBB.