Researchers have identified genetic markers in human blood samples that are believed to be linked to post-traumatic stress disorder (PTSD).
The markers in question are linked to gene networks responsible for regulating immune function and interferon signaling, the University of California, San Francisco reported. The researchers believe the findings could lead to improvements in PTSD diagnosis and treatment, and even predict individuals who are more susceptible to the mental illness.
Past genomic studies of PTSD have looked at differences in gene expression between individuals with and without PTSD, but this new study provides a broader approach that include whole transcriptome RNA sequencing.
"By comparing U.S. Marines who develop PTSD symptoms to those who do not, we can measure differences in genes, but also take into consideration the dynamic relationships between and among them, their connectivity," said first author Michael S. Breen, of the University of Southampton. "Because PTSD is thought to be such a complex disorder, measuring these dynamic relationships is crucial to better understanding the PTSD pathology."
To make their findings, the researchers looked at blood samples from 188 U.S. Marines before and after deployment to conflict zones. They were able to pinpoint modules of co-regulated genes that influenced immune responses and interferon signaling associated with PTSD.
"What's interesting is that molecular signatures of innate immunity and interferon signaling were identified both after developing PTSD as well as before developing PTSD," said Dewleen G. Baker, MRS-II principal investigator, research director at the VA Center of Excellence for Stress and Mental Health, and professor in the Department of Psychiatry at UC San Diego.
The researchers now hope to gain insight into what causes the interferon stimulation before events occur that trigger the symptoms of PTSD. Despite this gap in knowledge, the researchers said the recent study is "intriguing" because it backs up past evidence that changes in the peripheral blood could lead to pathological changes in the brain down the road.
"Since our causal (pre-deployment) and consequential (post-deployment) discoveries are based upon peripheral blood samples, these results suggest that identifying individuals at risk for PTSD development may be achievable through high-throughput profiling of molecular data," said Christopher H. Woelk, reader in genomics and bioinformatics at University of Southampton and assistant adjunct professor at UC San Diego School of Medicine.
The findings were published in a recent edition of the journal Molecular Psychiatry.
