Chronic inflammation is a key factor in symptomology and comorbidities of post-traumatic stress disorder (PTSD). Levels of a proinflammatory marker, C-reactive protein (CRP) are increased in individuals with PTSD but it is not clear if this is due to trauma exposure or PTSD. Our study aimed to assess the relationship between serum CRP levels, CRP SNPs, methylation, mRNA expression and PTSD in a homogenous trauma exposed Australian Vietnam veteran cohort. We hypothesized that decreased DNA methylation would be associated with increased gene expression and increased peripheral CRP levels in PTSD patients and that this would be independent of trauma.

Participants were 299 Vietnam veterans who had all been exposed to trauma and approximately half were diagnosed with PTSD. We observed higher levels of serum CRP in the PTSD group compared to the non-PTSD group but after controlling for BMI and triglycerides the association did not remain significant. No association was found between CRP SNPs and PTSD or CRP levels. Absent in Melanoma 2 (AIM2) which is a mediator of inflammatory response and a determinant of CRP levels was analysed for DNA methylation and mRNA expression. We observed a trend level association between PTSD and AIM2 methylation after controlling for age, smoking, triglycerides, BMI and cell types. There was no significant interaction between PTSD and CRP levels on AIM2 methylation after controlling for covariates. We observed that as AIM2 methylation levels decreased, AIM2 mRNA expression increased. Elevated CRP levels were associated with AIM2 mRNA in the trauma exposed cohort but there was no significant interaction effect with PTSD. Our results could not confirm that CRP is a marker of PTSD independent of trauma in this group of older veterans. CRP may be a broad marker of disease risk, or a marker of PTSD in younger cohorts than those in this study.

慢性炎症是创伤后应激障碍 (PTSD) 的症状和合并症的关键因素。PTSD 患者的促炎标志物 C 反应蛋白 (CRP) 水平升高，但尚不清楚这是由于创伤暴露还是 PTSD。我们的研究旨在评估暴露于同种创伤的澳大利亚越战退伍军人队列中血清 CRP 水平、CRP SNP、甲基化、mRNA 表达和 PTSD 之间的关系。我们假设在 PTSD 患者中，DNA 甲基化减少与基因表达增加和外周 CRP 水平增加有关，并且这与创伤无关。

参与者是 299 名越南退伍军人，他们都遭受过创伤，大约一半被诊断出患有创伤后应激障碍。我们观察到 PTSD 组的血清 CRP 水平高于非 PTSD 组，但在控制 BMI 和甘油三酯后，相关性不再显着。未发现CRP SNP 与 PTSD 或 CRP 水平之间存在关联。分析了黑色素瘤 2 (AIM2) 中不存在的炎症反应介质和 CRP 水平的决定因素的 DNA 甲基化和 mRNA 表达。我们观察到 PTSD 和AIM2之间的趋势水平关联控制年龄、吸烟、甘油三酯、BMI 和细胞类型后的甲基化。在控制协变量后，PTSD 和 CRP 水平对 AIM2 甲基化没有显着的相互作用。我们观察到随着AIM2甲基化水平降低，AIM2 mRNA 表达增加。在创伤暴露队列中，升高的 CRP 水平与AIM2 mRNA相关，但与 PTSD 没有显着的交互作用。我们的结果无法证实 CRP 是这组老年退伍军人中独立于创伤的 PTSD 标志物。CRP 可能是一个广泛的疾病风险标志物，或者是比本研究中年轻队列的 PTSD 标志物。