National University Health System, Singapore
Dr. Cyrus Ho
“Given the multifaceted nature of MDD, the multiple small but dynamic genetic alterations in biomolecular pathways, which are modulated by epigenetic modifications, could contribute to a better understanding of the underlying aetiology and pathophysiology of this disorder,” wrote Cyrus Su Hui Ho, MD, of National University Health System, Singapore, and colleagues. However, studies of biomarkers in psychiatry are limited, and the predictive potential of microribonucleic acids (miRNAs) has not been examined, they said.
In a study published in Comprehensive Psychiatry, the researchers identified 60 adults with depression and 60 healthy controls. Depression severity was assessed with the Hamilton Depression Rating Scale. Other demographic and clinical characteristics were similar between the patients and controls; 10 patients were unmedicated.
The researchers used QUIAGEN Ingenuity Pathway Analysis to identify the specific depression-related biological pathways affected by various miRNAs.
A total of six miRNAs (miR-542-3p, miR-181b-3p, miR-190a-5p, miR-33a-3p, miR-3690, and miR-6895-3p) were down-regulated in unmedicated depressed patients, compared with healthy controls.
In a receiver operating characteristic (ROC) analysis, a combination panel with three miRNAs (miR-542-3p, miR-181b-3p, and miR-3690) in whole blood yielded an area under the curve (AUC) of 0.67. This combination correctly classified 66.7% of MDD patients and 63.3% of healthy controls.
The ability of individual miRNAs to differentiate between MDD patients and controls in the current study was limited, the researchers wrote in their discussion. “However, when three miRNAs (miR-542b-3p, miR-181b-3p, and miR-3690) were combined as a panel, the AUC was enhanced to an almost acceptable degree (AUC of 0.67, approaching 0.7) and might have value in complementing clinical diagnoses,” they said.
The study findings were limited by several factors including the small sample size and the use of medications by most MDD patients, which resulted in an especially small number of unmedicated patients, the researchers noted. Other limitations included the use of study population from a single center, and the inability to explain the link between blood and brain miRNA expression, they said.
However, the study is the first clinical trial in Singapore to examine the role of miRNA in depression and to identify miRNAs as potential biomarkers for MDD, they said.
Additional studies are needed to explore miRNA biomarkers for diagnosis, disease prognosis, and treatment response in MDD, they concluded.
The study was supported by the National University Health System Seed Fund. The researchers had no financial conflicts to disclose.