Summary:
The aim of this study was the investigation of the interaction of immune
mediators with tryptophan metabolism, neural plasticity and endocrine
function,as well as their changes under successful antidepressive treatment in
major depression (MDD). We assessed IFN-γ, TNF-α, PGE2, IL-4,2,3-dioxygenase of
indoleamine (IDO), BDNF, serotonin and 5-HIAA using ELISA, CRP using
nephelometry and cortisol, prolactin using luminescence technique. Forty
patients suffering from MDD and forty controls participated in the study. On
admission and before discharging from hospital patients were rated on Hamilton
Scale and blood was collected.Twenty of the patients underwent pharmacotherapy,
though the rest followed electroconvulsive therapy.The concentrations of the
inflammatory mediators, IDO, cortisol, prolactin levels were significantly
increased in patients, though serotonin and BDNF levels were significantly
decreased compared to those of the controls'. Post treatment TNF-α, IDO,
cortisol and prolactin levels decreased.The IDO changes were strongly
positively correlated with patients' clinical improvement. Our findings suggest
that induced production of IDO by inflammatory mediators results in reduced
serotonin synthesis and could contribute to reduced BDNF production, through
overproduction of neurotoxic metabolites. Moreover, IDO plays an important role
in the pathophysiology of MDD and effective antidepressive therapy of various
modalities reduces IDO production. Finally, the assessment of IDO serum
concentration with ELISA might be a useful peripheral marker in MDD.
Keywords:
Psychoimmunological parameters, Major depression, Tryptophan metabolism, Inflammatory mediators, Antidepressive treatment