Liu X, Erikson C, Brun A
Department of Neuropathology, Lund University, Sweden.
Dementia. 1996 May-Jun;7(3):128-34. doi: 10.1159/000106867.
The most important new development during recent years in the field of degenerative dementia concerns synaptic pathology. So far it has been investigated in some regions and some cortical laminae in Alzheimer's disease (AD). The present communication is a more comprehensive study of all laminae in four different regions, the prefrontal, parietal, inferior temporal and posterior cingulate cortex. Against the background of normal aging, AD was compared with another degenerative disorder, frontal lobe degeneration of non-Alzheimer type (FLD). The synapse density was measured using synaptophysin as a marker. Astrocytes were also counted in the molecular layer. In normals, the cortex showed successively lower synaptic density from layer I to layer VI and relatively lowest density in the prefrontal cortex and a general decline with increasing age. A 46-49% decrease in synaptic density was found in all laminae in all regions of AD brains, a finding different from that in FLD. The number of astrocytes increased significantly in the prefrontal cortex both in AD and FLD but parietally only in AD. These results contribute to the understanding of normal synaptic organization of cortex, demonstrate the laminar and regional distribution of synaptic loss in AD and underscore the difference between AD and FLD. The gliosis appears to be secondary to the neurodegenerative changes. Synaptic loss is likely to be a common pathogenetic feature of neurodegenerative disorders and a likely cause of clinical symptoms and regional metabolic decrements in dementia.
近年来，在退行性痴呆领域最重要的新进展涉及突触病理学。到目前为止，已经在阿尔茨海默病（AD）的一些区域和一些皮质层进行了研究。本报告是对四个不同区域（前额叶、顶叶、颞下回和后扣带回皮质）所有层的更全面研究。在正常衰老的背景下，将AD与另一种退行性疾病——非阿尔茨海默型额叶变性（FLD）进行了比较。使用突触素作为标志物测量突触密度。还对分子层中的星形胶质细胞进行了计数。在正常人中，皮质从I层到VI层的突触密度依次降低，前额叶皮质的密度相对最低，并且随着年龄的增长普遍下降。在AD脑的所有区域的所有层中发现突触密度降低了46%-49%，这一发现与FLD不同。在AD和FLD中，前额叶皮质的星形胶质细胞数量均显著增加，但仅在AD中顶叶的星形胶质细胞数量增加。这些结果有助于理解皮质的正常突触组织，证明AD中突触丧失的层状和区域分布，并强调AD和FLD之间的差异。胶质增生似乎继发于神经退行性变化。突触丧失可能是神经退行性疾病的一个共同致病特征，也是痴呆临床症状和区域代谢减退的一个可能原因。
