Transforming growth factor-β1 and major depressive disorder with and without attempted suicide: Preliminary study

A substantial body of evidence indicates that dysregulation of the immune system is associated with suicidal behavior in major depressive disorder (MDD). Transforming growth factor (TGF)-β1 is believed to be an important factor in regulating inflammatory responses and to have anti-inflammatory effects. We aimed to identify the role of TGF-β1 on suicidal depression. The TGF-β1 polymorphisms at codons 10 and 25 were analyzed in 122 suicidal MDD patients, 61 non-suicidal MDD patients, and 120 control subjects and, among them, in vitro TGF-β1 productions were measured in 48 suicidal MDD patients, 47 non-suicidal MDD patients, and 91 control subjects. There was no genetic polymorphism at codon 25 and three genotypes at codon 10. No significant difference in the distributions of the TGF-β1 genotypes was found among the three groups. The in vitro TGF-β1 productions were significantly higher in suicidal MDD patients (844.3 ± 329.7 pg/ml) and in non-suicidal MDD patients (853.0 ± 439.7 pg/ml) than in controls (683.0 ± 397.0 pg/ml) (P = 0.01). In vitro TGF-β1 productions were not significantly different among patients with any of the TGF-β1 alleles or genotypes. Our findings suggest that in vitro TGF-β1 productions play an important role on MDD, but we found no associations between TGF-β1 and suicidal behavior.