基于结构和功能磁共振成像研究海马在原发干燥综合征认知损害神经机制中的作用

Primary Sjögren’s syndrome (pSS) is a common and vital systemic autoimmune disease. The prevalence of cognitive impairment in patients with pSS has reported up to 50%. The underlying neural traits are not fully uncovered. Hippocampus has been reported to play an important role in neural mechanism of cognitive impairment in many systemic autoimmune diseases. Previously, our group found abnormal resting-state brain activity in patients with systemic lupus erythematosus (SLE) which is an important systemic autoimmune disease. Providing that pSS and SLE share some similar pathological mechanism, and hippocampus atrophy has been found in pSS, we assume that hippocampus play important role in neural mechanism of cognitive impairment in pSS as well. However, the structural and functional traits are unclear. Thus, by using structural and functional MRI, we are going to study the alteration of structure (volumes of hippocampal subregions, topological features of structural network based on diffusion tensor imaging) and function (regional brain activity, functional connectivity density, effective connectivity, and topological features of functional network) in patients with pSS. Additionally, we are going to study the relation between the neural imaging metrics and neurophysiological tests and autoimmune antibody. Our aim is to uncover the structural and functional basics of hippocampus in the neural mechanism of cognitive impairment in patients with pSS, and to provide objective neuroimaging evidences for diagnosis and intervention of cognitive impairment in patient with pSS in the future.

原发干燥综合征（pSS）是一种常见且重要的系统性自身免疫性疾病。pSS患者认知损害发生率达50%，其具体神经机制尚不明确。研究表明海马在多种自身免疫性疾病认知损害的发生中扮演重要角色。本项目组前期研究发现重要自身免疫疾病系统性红斑狼疮（SLE）患者海马静息态脑功能活动异常。pSS与SLE具有许多相似的病理机制，且pSS患者海马萎缩，因而我们推测海马在pSS患者认知损害神经机制中也起重要作用，然而其结构和功能基础不明。本项目拟应用结构和功能磁共振成像探讨pSS患者海马结构（亚区体积、基于扩散张量成像的结构网络拓扑特性）和静息态脑功能（局部脑活动、功能连接密度、效应连接及功能网络拓扑特性）的改变，分析神经影像指标与神经心理量表及自身免疫抗体的关系，预期阐明海马在pSS患者认知损害神经机制中作用的结构和功能基础，为未来pSS患者认知损害诊断及干预提供客观的影像学依据。

原发干燥综合征（pSS）患者认知损害具体神经机制尚不明确。海马结构和功能异常是多种系统性自身免疫疾病的重要表现。本研究借助多模态MRI探索研究海马潜在灰质体积、白质微结构和静息态功能改变在pSS认知功能损害神经机制中的作用。本研究发现：①pSS病人右侧枕叶、颞叶皮层海马静息态功能连接减低。②SS病人合并系统性红斑狼疮时，包括海马结构在内的，静息态ALFF减低的脑区更多。③pSS病人DKI显示的白质微结构损害。④pSS病人基于DTI结构网络指标异常。这些影像标记物可能为认知损害诊断及治疗提供客观的影像学依据。