Mamah Daniel, Chen ShingShiun, Shimony Joshua S, Harms Michael P
Department of Psychiatry, Washington University School of Medicine, St. Louis, MO, United States.
Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, MO, United States.
Front Psychiatry. 2024 Feb 1;15:1240502. doi: 10.3389/fpsyt.2024.1240502. eCollection 2024.
Structural brain connectivity abnormalities have been associated with several psychiatric disorders. Schizophrenia (SCZ) is a chronic disabling disorder associated with accelerated aging and increased risk of dementia, though brain findings in the disorder have rarely been directly compared to those that occur with aging.
We used an automated approach to reconstruct key white matter tracts and assessed tract integrity in five participant groups. We acquired one-hour-long high-directional diffusion MRI data from young control (CON, n =28), bipolar disorder (BPD, n =21), and SCZ (n =22) participants aged 18-30, and healthy elderly (ELD, n =15) and dementia (DEM, n =9) participants. Volume, fractional (FA), radial diffusivity (RD) and axial diffusivity (AD) of seven key white matter tracts (anterior thalamic radiation, ATR; dorsal and ventral cingulum bundle, CBD and CBV; corticospinal tract, CST; and the three superior longitudinal fasciculi: SLF-1, SLF-2 and SLF-3) were analyzed with TRACULA. Group comparisons in tract metrics were performed using multivariate and univariate analyses. Clinical relationships of tract metrics with recent and chronic symptoms were assessed in SCZ and BPD participants.
A MANOVA showed group differences in FA (λ=0.5; p=0.0002) and RD (λ=0.35; p<0.0001) across the seven tracts, but no significant differences in tract AD and volume. Post-hoc analyses indicated lower tract FA and higher RD in ELD and DEM groups compared to CON, BPD and SCZ groups. Lower FA and higher RD in SCZ compared to CON did not meet statistical significance. In SCZ participants, a significant negative correlation was found between chronic psychosis severity and FA in the SLF-1 (r= -0.45; p=0.035), SLF-2 (r= -0.49; p=0.02) and SLF-3 (r= -0.44; p=0.042).
Our results indicate impaired white matter tract integrity in elderly populations consistent with myelin damage. Impaired tract integrity in SCZ is most prominent in patients with advanced illness.
脑结构连接异常与多种精神疾病有关。精神分裂症（SCZ）是一种慢性致残性疾病，与加速衰老和痴呆风险增加有关，尽管该疾病的脑部表现很少与衰老相关的表现直接进行比较。
我们采用自动化方法重建关键白质束，并评估了五个参与者组的束完整性。我们从18 - 30岁的年轻对照组（CON，n = 28）、双相情感障碍（BPD，n = 21）和精神分裂症（SCZ，n = 22）参与者以及健康老年人（ELD，n = 15）和痴呆症（DEM，n = 9）参与者中获取了长达一小时的高分辨率扩散MRI数据。使用TRACULA分析了七条关键白质束（丘脑前辐射，ATR；背侧和腹侧扣带束，CBD和CBV；皮质脊髓束，CST；以及三条上纵束：SLF - 1、SLF - 2和SLF - 3）的体积、分数各向异性（FA）、径向扩散率（RD）和轴向扩散率（AD）。使用多变量和单变量分析进行束指标的组间比较。在SCZ和BPD参与者中评估了束指标与近期和慢性症状的临床关系。
一项多变量方差分析显示，七条束在FA（λ = 0.5；p = 0.0002）和RD（λ = 0.35；p < 0.0001）方面存在组间差异，但束的AD和体积无显著差异。事后分析表明，与CON、BPD和SCZ组相比，ELD和DEM组的束FA较低，RD较高。SCZ组与CON组相比，FA较低和RD较高未达到统计学显著性。在SCZ参与者中，慢性精神病严重程度与SLF - 1（r = - 0.45；p = 0.035）、SLF - 2（r = - 0.49；p = 0.02）和SLF - 3（r = - 0.44；p = 0.042）中的FA之间存在显著负相关。
我们的结果表明老年人群白质束完整性受损，与髓鞘损伤一致。SCZ中束完整性受损在病情较重的患者中最为突出。
