Inflammatory Markers and Brain Volume in Patients with Post-traumatic Stress Disorder

Objective: Posttraumatic stress disorder (PTSD) is characterized by increased inflammatory processing and altered brain volume. In this study, we investigated the relationship between inflammatory markers and brain volume in patients with PTSD. Methods: Forty-five patients with PTSD, and 70 healthy controls (HC) completed clinical assessments and self-reported psychopathology scales. Factors associated with inflammatory responses including brain-derived neurotrophic factor and four inflammatory biomarkers (C-reactive protein, cortisol, Interleukin-6, and homocysteine) and T1-magnetic resonance imaging of the brain were measured. Results: In the PTSD group, cortisol level was significantly lower (t = 2.438, p = 0.046) than that of the HC. Cortisol level was significantly negatively correlated with the left thalamus proper (r = -0.369, p = 0.035), right thalamus proper (r = -0.394, p = 0.014), right frontal pole (r = -0.348, p = 0.039), left occipital pole (r = -0.338, p = 0.044), and right superior occipital gyrus (r = -0.397, p = 0.008) in patients with PTSD. However, these significant correlations were not observed in HC. Conclusion: Our results indicate that increased cortisol level, even though its average level was lower than that of HC, is associated with smaller volumes of the thalamus, right frontal pole, left occipital pole, and right superior occipital gyrus in patients with PTSD. Cortisol, a major stress hormone, might be a reliable biomarker to brain volumes and pathophysiological pathways in patients with PTSD.