Pan Jie, Hu Jin, Meng Danyang, Chen Liang, Wei Xianling
Department of Neurology, The First Hospital of Jiaxing (Affiliated Hospital of Jiaxing University), Jiaxing City, Zhejiang Province, China.
Department of Head and Neck Surgery, The First Hospital of Jiaxing (Affiliated Hospital of Jiaxing University), Jiaxing City, Zhejiang Province, China.
Medicine (Baltimore). 2024 May 3;103(18):e38086. doi: 10.1097/MD.0000000000038086.
Dementia is a major public health challenge for aging societies worldwide. Neuroinflammation is thought to be a key factor in dementia development. The aim of this study was to comprehensively assess translocator protein (TSPO) expression by positron emission tomography (PET) imaging to reveal the characteristics of neuroinflammation in dementia.
We used a meta-analysis to retrieve literature on TSPO expression in dementia using PET imaging technology, including but not limited to the quality of the study design, sample size, and the type of TSPO ligand used in the study. For the included studies, we extracted key data, including TSPO expression levels, clinical characteristics of the study participants, and specific information on brain regions. Meta-analysis was performed using R software to assess the relationship between TSPO expression and dementia.
After screening, 12 studies that met the criteria were included. The results of the meta-analysis showed that the expression level of TSPO was significantly elevated in patients with dementia, especially in the hippocampal region. The OR in the hippocampus was 1.50 with a 95% CI of 1.09 to 1.25, indicating a significant increase in the expression of TSPO in this region compared to controls. Elevated levels of inflammation in the prefrontal lobe and cingulate gyrus are associated with cognitive impairment in patients. This was despite an OR of 1.00 in the anterior cingulate gyrus, indicating that TSPO expression in this region did not correlate significantly with the findings. The overall heterogeneity test showed I² = 51%, indicating moderate heterogeneity.
This study summarizes the existing literature on TSPO expression in specific regions of the brain in patients with dementia, and also provides some preliminary evidence on the possible association between neuroinflammation and dementia. However, the heterogeneity of results and limitations of the study suggest that we need to interpret these findings with caution. Future studies need to adopt a more rigorous and consistent methodological design to more accurately assess the role of neuroinflammation in dementia, thereby providing a more reliable evidence base for understanding pathological mechanisms and developing potential therapeutic strategies.
痴呆是全球老龄化社会面临的一项重大公共卫生挑战。神经炎症被认为是痴呆发展的关键因素。本研究的目的是通过正电子发射断层扫描（PET）成像全面评估转位蛋白（TSPO）的表达，以揭示痴呆中神经炎症的特征。
我们采用荟萃分析，检索使用PET成像技术研究痴呆中TSPO表达的文献，包括但不限于研究设计质量、样本量以及研究中使用的TSPO配体类型。对于纳入的研究，我们提取关键数据，包括TSPO表达水平、研究参与者的临床特征以及脑区的具体信息。使用R软件进行荟萃分析，以评估TSPO表达与痴呆之间的关系。
筛选后，纳入了12项符合标准的研究。荟萃分析结果显示，痴呆患者中TSPO的表达水平显著升高，尤其是在海马区。海马区的比值比为1.50，95%置信区间为1.09至1.25，表明该区域TSPO的表达与对照组相比显著增加。前额叶和扣带回炎症水平升高与患者的认知障碍有关。尽管前扣带回的比值比为1.00，表明该区域TSPO表达与研究结果无显著相关性。总体异质性检验显示I² = 51%，表明存在中度异质性。
本研究总结了痴呆患者大脑特定区域TSPO表达的现有文献，并为神经炎症与痴呆之间的可能关联提供了一些初步证据。然而，结果的异质性和研究的局限性表明，我们需要谨慎解释这些发现。未来的研究需要采用更严格和一致的方法设计，以更准确地评估神经炎症在痴呆中的作用，从而为理解病理机制和制定潜在治疗策略提供更可靠的证据基础。
