Close to a million people commit suicide each year worldwide. A significant percentage of those that commit suicide suffer from depression. Half of the depressed patients who died of suicide had medical visits within an average of three months of death. Therefore, the ability to more reliably predict suicide risk is clinically valuable and could be lifesaving. Traditional suicide risk assessment relies on patients who rarely reveal the intent, and the approaches have low predictability. Therefore, more reliable quantitative biomarkers of suicide risk could have a significant impact on the reduction of suicide deaths.
Non-coding RNAs may be viable candidates for biomarkers of suicidal potential. One type, long noncoding RNA (lncRNA) includes RNA strands of over 200 nucleotides in length and are involved in the regulation of gene expression. Antisense lncRNA has been detected in the postmortem brain tissue of those who committed suicide, but not in patients with depression. Therefore, researchers set out to study the relationship between the expression of lncRNA in peripheral blood mononuclear cells and suicide risk in patients with major depressive disorder.
Blood was collected from patients with major depressive disorder and those without a family history of the disorder. Patients were grouped based on the presence or absence of suicidal ideation and past suicide attempt. Total RNA was extracted from peripheral blood mononuclear cells, and the expression of six different lncRNAs was analyzed by reverse-transcription polymerase chain reaction. The results showed that the expression of all six lncRNAs were lower in the peripheral blood mononuclear cells of the suicidal ideation group compared to the non- suicidal ideation and control groups. Likewise, the expression of all six lncRNAs was lower in the past suicide attempt group compared to the no attempt and control groups.
These study results suggest that lncRNAs may represent a part of the molecular mechanism related to major depressive disorder. They also may potentially serve as quantifiable markers that can predict suicide risk in patients with depression. The use of such a biomarker may help healthcare teams in the future to take preventive measures to reduce or eliminate the chance of suicide in patients with depression.
Cui, X., Niu, W., Kong, L., He, M., Jiang, K., & Chen, S. et al. (2017). Long noncoding RNA expression in peripheral blood mononuclear cells and suicide risk in Chinese patients with major depressive disorder. Brain And Behavior, 7(6), e00711. doi:10.1002/brb3.711