A research team at Korea University Anam Hospital (KUAH) found that patients with depression have higher expression levels of inflammation-related genes than those without depression.
Depression is known to have a variety of biological causes. Recently, it has been suggested that chronic inflammatory conditions can lead to functional abnormalities in the brain, which may lead to depression.
The team, led by Professors Ham Byung-joo and Han Kyu-man of the Department of Neuropsychiatry at KUAH, found that animals with depression-like behavioral patterns had increased expression of genes related to interferon, a pathway that regulates inflammation.
Professors Shin Chan-young at Konkuk University and Ahn Tae-jin at Handong University also participated in the study.
Using the preclinical data, the team analyzed genomic data from 350 depressed patients and 161 healthy controls between the ages of 19 and 64, looking for changes in specific parts of the genome.
As a result, they found that the depressed patients had altered DNA methylation of genes involved in regulating inflammation compared to the healthy controls, which was consistent with animal studies.
Afterward, the team used brain MRIs to compare differences in cortical thickness between depressed patients and normal controls, and found that depressed patients had decreased cortical thickness in the frontal lobe.
“The team used brain MRIs to compare differences in cortical thickness between depressed patients and normal controls, and found that depressed patients had decreased cortical thickness in the frontal lobe as DNA methylation of inflammation-related genes increased,” Professor Ham said. “This study shows that the expression of inflammation-related genes can cause structural changes in the brain as well as depression, which could be used as a biomarker to assess an individual's vulnerability to developing depression.”
Professor Han also said, “The study provides a new way to measure an individual's risk of developing depression.”
Genetic testing is expected to enable early detection of individuals at high risk of developing depression and provide preventive treatment services, Han added.
The research results were published in the online edition of Brain, Behavior, and Immunity.