Are there differences in lipid peroxidation and immune biomarkers between major depression and bipolar disorder: Effects of melancholia, atypical depression, severity of illness, episode number, suicidal ideation and prior suicide attempts

Prog Neuropsychopharmacol Biol Psychiatry. 2018 Feb 2:81:372-383. doi: 10.1016/j.pnpbp.2017.08.024. Epub 2017 Sep 1.

Abstract

Background: There is evidence that major depression (MDD) and bipolar disorder (BD) are accompanied by activated immune & oxidative (I&O) pathways.

Methods: To compare I&O biomarkers between MDD and BD we assessed serum levels of thiobarbituric acid reactive substances (TBARS; a lipid peroxidation marker), soluble interleukin-2 receptor (sIL-2R), sIL-6R, IL-α, sIL-1R antagonist (sIL-1RA), tumor necrosis factor receptor 60kDa/80kDa (sTNFR60/R80) in 114 MDD and 133 BD patients, and 50 healthy controls. We computed z-unit weighted indices reflecting the 5 cytokine receptor levels (zCytR), cell-mediated immunity (zCMI) and I&O pathways (zCMI+TBARS).

Results: There are no significant differences in biomarkers between MDD and BD. BD/MDD with atypical features is characterized by increased sIL-6R and TBARS, whereas melancholia is associated with higher TBARS and lower sTNFR60 levels. Severity of illness, as measured with the Hamilton Depression Rating Scale, is correlated with increased sIL-6R, sTNFR80, TBARS, zCytR and zCMI+TBARS. The number of episodes the year prior to blood sampling is positively associated with sTNFR80, TBARS, zCMI, zCMI+TBARS, while number of hospitalizations is positively associated with sIL-1RA. Prior suicidal attempts are associated with increased sIL-1RA, IL-1α, zCMI, TBARS and zCMI+TBARS, while TBARS is associated with current suicidal ideation.

Conclusions: There are no I&O biomarker differences between MDD and BD. Atypical depression is associated with increased IL-6 trans-signaling and lipid peroxidation. Severity of depression, number of episodes and suicidal attempts are associated with activated I&O pathways. Increased TBARS is the single best predictor of BD/MDD, atypical depression, melancholia and current suicidal ideation.

Keywords: Bipolar disorder; Cytokines; Immune; Major depression; Melancholia; Oxidative stress.

Publication types

  • Comparative Study

MeSH terms

  • Adult
  • Aged
  • Biomarkers / blood
  • Bipolar Disorder / blood*
  • Bipolar Disorder / immunology*
  • Bipolar Disorder / psychology
  • Bipolar Disorder / therapy
  • Case-Control Studies
  • Depressive Disorder, Major / blood*
  • Depressive Disorder, Major / immunology*
  • Depressive Disorder, Major / psychology
  • Depressive Disorder, Major / therapy
  • Female
  • Hospitalization
  • Humans
  • Interleukin-6 / blood
  • Lipid Peroxidation / physiology
  • Male
  • Middle Aged
  • Psychiatric Status Rating Scales
  • Severity of Illness Index
  • Suicidal Ideation
  • Suicide, Attempted
  • Thiobarbituric Acid Reactive Substances / metabolism
  • Young Adult

Substances

  • Biomarkers
  • IL6 protein, human
  • Interleukin-6
  • Thiobarbituric Acid Reactive Substances