Potential Biomarker for PTSD

The first study (Zhang et al., 2008) identified a potential biomarker for PTSD, a protein and its associated gene known as p11. This finding has significant implications for posttraumatic stress disorder (PTSD) diagnosis and treatment since it was discovered in both animal models and human PTSD brain tissue. Biomarkers are increasingly used to diagnose diseases promptly and accurately, to identify individuals at high-risk for certain diseases and to follow the course of treatment. In the absence of clinical biomarkers for PTSD, diagnosis has been dependant on only the assessment of clinical symptoms. These symptoms are often missed, misdiagnosed and/or left untreated in thousands of affected individuals (military and civilian), thus disrupting the quality of their lives and the lives of their families and children.

The Zhang et al. study was the first to use human post-mortem brain tissue from individuals who had PTSD. Researchers discovered that p11 (a protein present in all individuals) decreased in patients with depression, a condition often co-morbid with PTSD, but the new findings from CSTS scientists indicated it is increased in patients with PTSD. CSTS scientists further discovered a possible molecular mechanism that could explain the increase of p11 in PTSD and the decrease of p11 in depression. Using state of the art techniques of molecular biology, they found that three glucocorticoid (stress hormones) receptor-binding sites reside in the human p11 gene. These sites may regulate p11 gene expression and p11 levels via their interaction with stress hormones in PTSD patients.

This research area has significant implications for understanding and treating PTSD: 1) the level of p11 may be a biomarker for diagnosing PTSD, as well as for differentiating PTSD from depression; 2) the identification of three glucocorticoid receptor-binding sites suggests a therapeutic target for development of clinical interventions to block or alter p11 levels for PTSD prevention and treatment; and, 3) the presence of p11 in tissue and therefore blood may lead to PTSD screening and monitoring for purposes of disease prediction, diagnosis, and prognosis.