阿尔茨海默病嗅觉障碍研究进展

Research progress on olfactory dysfunction in Alzheimer's disease

阿尔茨海默病(Alzheimer’s disease,AD)患者在出现认知功能障碍之前,普遍表现出嗅觉相关功能障碍,而且嗅觉系统病变程度与AD进展密切相关。因此,嗅觉系统功能障碍可能成为早期诊断AD及评价其进展的指标。近几年通过对AD患者和AD转基因动物模型的研究发现,嗅觉系统可能是AD退行性病变的始发部位,而且具有从外周向中枢发展的趋势,即病变首先发生于嗅觉系统的近外周部分(嗅上皮、嗅球等),然后发展至嗅皮层(梨状皮层、内嗅皮层等),进而累及海马和新皮层区等。此外,AD病理改变的这种时空模式与嗅觉相关行为障碍、神经通路及递质的改变等具有很高的相关性。重点综述了以上方面的研究结果。

Olfactory dysfunction is a common symptom in patients with Alzheimer＇s disease （AD）, and occurs before cognitive impairment. The severity of the neuropathological changes in olfactory system was closely related to AD progression. Therefore, olfactory dysfunctions might be potential biomarkers for early diagnosis and evaluation of AD progression. In the past decade, researches on patients with AD and transgenic AD models have found that olfactory system might be the earliest brain areas where neurodegenerative changes arise. Furthermore, the neuropathological changes show a tendency to spread from peripheral to the central parts of the olfactory system, that is, start from the olfactory epithelium, olfactory bulb, then to olfactory cortices such as piriform cortex, entorhinal cortex, and finally spread to hippocampus and neocortex. Moreover, the spatial and temporal patterns of the neuropathological changes in AD were closely related to the olfactory impairments, the changes of neural pathway and neurotransmitters. In this paper, we summarized the results on these aspects.