| Summary: | 碩士 === 國立陽明大學 === 神經科學研究所 === 103 === There are many studies examined brain structural changes in the hippocampus of major depressive disorder (MDD) patients. However, only a few studies have focused on the results of hippocampal volumes with different methods of volume measurement and their association with clinical severity of depressive symptoms. The hypothesis of this study was that if there is an association between hippocampal volume and clinical severity of depressive symptoms.
Forty-five patients with first-episode, drug-naïve MDD and 45 healthy controls (HCs) with age- and gender- matched were recruited. All participants examined with 1.5T high-resolution magnetic resonance imaging and used three different methods of image analysis, including manual method, Statistical Parametric Mapping (SPM 12) and FreeSurfer (v5.3.0). Manual method was applied to analyze the longitudinal axis of hippocampal volumes, SPM was used to identify associated volumetric changes, FreeSurfer was used to analyze the volume of hippocampal subfields. Analysis of covariance (ANCOVAs) and partial correlation was used to compare the different volumes between MDD and HCs and their association of clinical severity of depressive symptoms. Clinical severity of depressive symptoms was evaluated by Montgomery Åsberg Depression Rating Scale (MARDS).
The participants in each group consisted with twelve male and thirty-three females (The average age in years was=MDD: 45.3±11.8 and, HCs: 45.3±11.3). The total hippocampal volume was significantly reduced in MDD compared with HCs (F=9.186, p=0.000). In the analysis of longitudinal axis, the hippocampal head (F=5.558, p=0.001) and body (F=4.643, p=0.002), but not tail (F=0.227, p=0.923) were significantly reduced in MDD. However, these reduced areas were not significantly correlated with the clinical severity of depressive symptoms. SPM with region-of–interest (ROI) analysis revealed that the gray-matter of right hippocampus (PFWE-correct=0.001) was significantly reduced. Results from the analysis of hippocampal subfields showed the reduction of areas included total Cornu Ammonis (CA) 2/3 (F=7.773, p=0.000), subiculum (F=3.901, p=0.006), CA4/DG (Dentate Gyrus) (F=7.962, p=0.000), presubiculum (F=4.264, p=0.003), hippocampus (F=3.355, p=0.013), CA1 (F=4.653, p=0.002), and fimbria (F=3.910, p=0.006). No any other areas showed significantly changed. Importantly, the reduction of CA2/3 (r=-0.367, p=0.023), and CA4/DG (r=-0.403, p=0.012) areas were significantly correlated with the clinical severity of depressive symptoms.
In conclusions, our data indicate that the hippocampal volumes were reduced in patients with first-episode, drug-naïve MDD. The reduced hippocampal CA2/3 and CA4/DG, which were well correlated with the clinical severity of depressive symptoms, reflect the important role of these areas in the pathophysiology of MDD.
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