Rationale and objectives

The hippocampus, especially the CA1, CA3, and dentate gyrus (DG) subfields, is reported to be associated with post-traumatic stress disorder (PTSD) after trauma. However, neuroimaging studies of the associations between PTSD and hippocampal subfield volumes have failed to yield consistent findings. The aim of this study is to examine whether the dopamine D2 receptor (DRD2) Taq1A polymorphism, which is associated with both hippocampal function and PTSD, moderated the association between PTSD severity and hippocampal CA1, CA3 and DG volumes.

Methods

T1-weighted images were acquired from 142 trauma survivors from the 2008 Wenchuan earthquake using a 3.0-T magnetic resonance imaging system. Hippocampal subfield segmentations were performed with FreeSurfer v6.0. We used the simple moderation model from the PROCESS v3.4 tool for SPSS 23.0 to examine the association between the rs1800497 polymorphism, PTSD severity, and hippocampal CA3 and DG volumes.

Results

A significant genotype × PTSD symptom severity interaction was found for the left CA3 volume (ΔF = 5.01, p = 0.008, ΔR² = 0.05). Post hoc, exploratory analyses deconstructing the interaction revealed that severe PTSD symptomatology were associated with reduced left CA3 volume among TC heterozygotes (t = − 2.86, p = 0.005).

Conclusions

This study suggests that DRD2 Taq1A polymorphism moderates the association between PTSD symptomatology and left CA3 volume, which promotes an etiological understanding of the hippocampal atrophy at the subfield level. This highlights the complex effect of environmental stress, and provides possible mechanism for the relationship between the dopaminergic system and hippocampal function in PTSD.

中文翻译：

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DRD2 Taq1A 多态性调节 PTSD 症状严重程度对左侧海马 CA3 体积的影响：一项初步研究

 理由和目标

据报道，海马体，尤其是 CA1、CA3 和齿状回 (DG) 亚区与创伤后应激障碍 (PTSD) 相关。然而，关于 PTSD 和海马亚区体积之间关联的神经影像学研究未能得出一致的结果。本研究的目的是检查与海马功能和 PTSD 相关的多巴胺 D2 受体 (DRD2) Taq1A 多态性是否调节 PTSD 严重程度与海马 CA1、CA3 和 DG 体积之间的关联。

 方法

使用 3.0-T 磁共振成像系统从 2008 年汶川地震中的 142 名创伤幸存者获取 T1 加权图像。使用 FreeSurfer v6.0 进行海马子区域分割。我们使用 SPSS 23.0 的 PROCESS v3.4 工具中的简单调节模型来检查 rs1800497 多态性、PTSD 严重程度以及海马 CA3 和 DG 体积之间的关联。

 结果

左侧 CA3 体积发现显着的基因型 × PTSD 症状严重程度交互作用（Δ F = 5.01， p = 0.008，Δ R ² = 0.05）。事后，解构相互作用的探索性分析表明，严重的 PTSD 症状与 TC 杂合子中左侧 CA3 体积减少相关（ t = − 2.86， p = 0.005）。

 结论

这项研究表明，DRD2 Taq1A 多态性调节了 PTSD 症状与左侧 CA3 体积之间的关联，从而促进了对亚区水平海马萎缩病因学的理解。这凸显了环境应激的复杂影响，并为 PTSD 中多巴胺能系统与海马功能之间的关系提供了可能的机制。