The Pathophysiological Role of Cytokines in Suicide Attempters with Major Depressive Disorder / 신경정신의학

OBJECTIVES: Cytokines are known to play an important role in the pathogenesis and the pathophysiology of major depressive disorders. However, the role of cytokines in suicide in major depression has not been explored thoroughly. The purpose of this study is to identify the roles of cytokine interaction of Th1, Th2, Th3 cytokines in suicidal depressive patients. METHODS: 110 major depressive patients (29 depressive patients without suicidal ideation, 32 depressive patients with suicidal ideation, and 49 depressive patients with suicide attempts) diagnosed by DSM-IV criteria were included in this study. The severity of suicide ideations and attempts was measured by Lethality of Suicide Attempt Rating Scale (LSARS) and Risk-Rescue Rating (RRR) system. Cytokine productions (TNF-alpha, IFN-gamma, IL-2, IL-4, and IL-6) upon mitogen stimulation were measured by ELISA in a whole blood assay. TGF-beta1 were measured in plasma by ELISA. RESULTS: There were no significant differences in age, sex and BMI among the three groups. IL-2 and IL-6 levels were significantly lower in the suicide attempt group than other two groups while TNF-alpha, IFN-gamma, IL-4 and TGF-beta1 did not differ among the groups. Significant positive correlations between TNF-alpha/IL-4, IL-6/IL-4, IFN-gamma/IL-4 and IL-6/TGF-beta1 ratio and LSARS scores in suicidal patients were found. In addition, there were significant correlations between TNF-alpha/IL-4 or IL-6/IL-4 and RRR scores in suicidal patients. CONCLUSION: These results indicate that decrease in Th1 cytokines may be associated with suicidal behavior in major depression. These findings suggest that cytokines may play a role in the pathogenesis of suicidal depression.

Decreased Concentration of Plasma Brain-Derived Neurotrophic Factor in Suicide Attempters

OBJECTS: Some studies have suggested that brain-derived neurotrophic factor(BDNF), one of the most important neurotrophins, is involved in pathophysiology of depression and suicide. This study was performed to determine whether there is an abnormality in plasma BDNF concentration in suicidal attempters. METHODS: The subjects were 71 suicidal attempters who visited emergency rooms in multi-medical centers. All subjects had been interviewed by using Structured Clinical Interview for DSM-IV(SCID), Hamilton Depression Rating Scale(HDRS), Young Mania Rating Scale(YMRS), and Positive And Negative Syndrome Scale(PANSS). The severity of the suicidal behavior was measured by Lethality of Suicide Attempt Rating Scale(LSARS) and Risk-Rescue Rating(RRR) system. Seventy-one age, sex, and diagnosis matched non-suicidal psychiatric patients who were consecutively admitted to a psychiatric ward during the same period recruited as psychiatric controls. They were drug-naive or drug-free at least more than 2 months. In addition, 80 healthy controls were randomly selected as normal controls. Plasma BDNF level was measured by the enzyme linked immunosorbent assay(ELISA) methods. RESULTS: In overall F-test, differences of the plasma BDNF levels among the groups were statistically significant(F=20.226, p<0.001). In the multiple comparisons(Scheffe), while mean levels of plasma BDNF between normal controls and non-suicidal psychiatric patients were similar(p=0.984), the BDNF levels of suicidal attempters were lower than those of other two groups(p<0.001). LSARS and RRR did not reveal any significant correlations with BDNF levels in suicidal attempters. CONCLUSION: These results suggest that reduction of plasma BDNF level is related to suicidal behavior and BDNF level may be a biological marker of suicidal behavior.