Interleukin-6 Gene Expression Changes after a 4-Week Intake of a Multispecies Probiotic in Major Depressive Disorder—Preliminary Results of the PROVIT Study

Abstract

Major depressive disorder (MDD) is a prevalent disease, in which one third of sufferers do not respond to antidepressants. Probiotics have the potential to be well-tolerated and cost-efficient treatment options. However, the molecular pathways of their effects are not fully elucidated yet. Based on previous literature, we assume that probiotics can positively influence inflammatory mechanisms. We aimed at analyzing the effects of probiotics on gene expression of inflammation genes as part of the randomized, placebo-controlled, multispecies probiotics PROVIT study in Graz, Austria. Fasting blood of 61 inpatients with MDD was collected before and after four weeks of probiotic intake or placebo. We analyzed the effects on gene expression of tumor necrosis factor (TNF), nuclear factor kappa B subunit 1 (NFKB1) and interleukin-6 (IL-6). In IL-6 we found no significant main effects for group (F(1,44) = 1.33, p = ns) nor time (F(1,44) = 0.00, p = ns), but interaction was significant (F(1,44) = 5.67, p < 0.05). The intervention group showed decreasing IL-6 gene expression levels while the placebo group showed increasing gene expression levels of IL-6. Probiotics could be a useful additional treatment in MDD, due to their anti-inflammatory effects. Results of the current study are promising, but further studies are required to investigate the beneficial effects of probiotic interventions in depressed individuals.

PROVIT: Supplementary Probiotic Treatment and Vitamin B7 in Depression—A Randomized Controlled Trial

“…Clinical visits included collection of fasting blood, stool, psychological and cognitive testing as well as a clinical interview including side effects of (study) medication and clinical symptoms. For results of the gene expression data of the study, see [25].…”

Effect of Psychobiotics on Psychometric Tests and Inflammatory Markers in Major Depressive Disorder: Meta-Analysis of Randomized Controlled Trials with Meta-Regression

“…Studies were predominantly conducted in Iran (N = 5) [21][22][23][24][25] but also in Austria (N = 2) [26,27], Poland (N = 1) [28] and Italy (N = 1) [29]. One study was conducted in two clinical centers, in Australia and Netherlands (N = 1) [30].…”

“…One trial was sponsored by industry (N = 1) [29], and no data on sponsorship was available for three studies (N = 3) [21,22,25]. In two trials, probiotic administration took place at hospital setting [26,27].…”

“…Altogether, 10 studies with 705 participants randomized and 603 analyzed were included [21][22][23][24][25][26][27][28][29][30]. All of patients were diagnosed with MDD, but different clinically well criteria were used, predominantly based on The Diagnostic and Statistical Manual of Mental Disorders (DSM) approaches.…”

“…Different probiotic strains were administered; however, in three studies conducted on the same population [21,22,24], the same Formula (named "Formula 2" for meta-regression purposes) was used: L. helveticus R0052 (Collection Nationale de Cultures de Microorganisms; CNCM strain I-1722) and B. longum R0175 (CNCM strain I-3470). In two studies (also the same population) [26,27], a mixture (reference Formula, R) of Bifidobacterium bifidum W23, Bifidobacterium lactis W51, Bifidobacterium lactis W52, L. acidophilus W22, Lactobacillus casei W56, L. paracasei W20, L. plantarum W62, Lactobacillus salivarius W24 and Lactococcus lactis W19 was administered. A similar probiotic cocktail was used in a study by Chahwan et al [30]; however, the studied product also contained L. acidophilus W37, Lactobacillus brevis W63 and Lactococcus lactis W58 instead of L. Altogether, 10 studies with 705 participants randomized and 603 analyzed were included [21][22][23][24][25][26][27][28][29][30].…”