Wilczyńska Karolina, Waszkiewicz Napoleon
Department of Psychiatry, Bialystok Medical University, 16-070 Choroszcz, Poland.
J Clin Med. 2020 Oct 27;9(11):3452. doi: 10.3390/jcm9113452.
Dementia is a group of disorders that causes dysfunctions in human cognitive and operating functions. Currently, it is not possible to conduct a fast, low-invasive dementia diagnostic process with the use of peripheral blood biomarkers, however, there is a great deal of research in progress covering this subject. Research on dementia biomarkers in serum validates anticipated health and economic benefits from early screening tests. Biomarkers are also essential for improving the process of developing new drugs.
The result analysis, of current studies on selected biomarker concentrations (Aβ40, Aβ42, t-tau, and YKL-40) and their combination in the serum of patients with dementia and mild cognitive disorders, involved a search for papers available in Medline, PubMed, and Web of Science databases published from 2000 to 2020.
The results of conducted cross-sectional studies comparing Aβ40, Aβ42, and Aβ42/Aβ40 among people with cognitive disorders and a control group are incoherent. Most of the analyzed papers showed an increase in t-tau concentration in diagnosed Alzheimer's disease (AD) patients' serum, whereas results of mild cognitive impairment (MCI) groups did not differ from the control groups. In several papers on the concentration of YKL-40 and t-tau/Aβ42 ratio, the results were promising. To date, several studies have only covered the field of biomarker concentrations in dementia disorders other than AD.
Insufficient amyloid marker test repeatability may result either from imperfection of the used laboratorial techniques or inadequate selection of control groups with their comorbidities. On the basis of current knowledge, t-tau, t-tau/Aβ42, and YKL-40 seem to be promising candidates as biomarkers of cognitive disorders in serum. YKL-40 seems to be a more useful biomarker in early MCI diagnostics, whereas t-tau can be used as a marker of progress of prodromal states in mild AD. Due to the insignificant number of studies conducted to date among patients with dementia disorders other than AD, it is not possible to make a sound assessment of their usefulness in dementia differential diagnostics.
痴呆症是一组导致人类认知和操作功能障碍的病症。目前，利用外周血生物标志物进行快速、低侵入性的痴呆症诊断过程尚无法实现，不过，针对该主题的大量研究正在进行中。血清中痴呆症生物标志物的研究证实了早期筛查测试在健康和经济方面的预期益处。生物标志物对于改进新药研发过程也至关重要。
对当前关于选定生物标志物浓度（Aβ40、Aβ42、总tau蛋白（t-tau）和YKL-40）及其在痴呆症和轻度认知障碍患者血清中的组合的研究结果进行分析，涉及在2000年至2020年发表的Medline、PubMed和科学网数据库中搜索相关论文。
在认知障碍患者和对照组中比较Aβ40、Aβ42和Aβ42/Aβ40的横断面研究结果并不一致。大多数分析论文显示，在已确诊的阿尔茨海默病（AD）患者血清中，t-tau浓度升高，而轻度认知障碍（MCI）组的结果与对照组并无差异。在几篇关于YKL-40浓度和t-tau/Aβ42比值的论文中，结果很有前景。迄今为止，仅有几项研究涉及除AD之外的痴呆症疾病中生物标志物浓度领域。
淀粉样蛋白标志物测试重复性不足可能是由于所用实验室技术不完善或对照组及其合并症选择不当所致。基于目前的知识，t-tau、t-tau/Aβ42和YKL-40似乎有望成为血清中认知障碍的生物标志物。YKL-40似乎是早期MCI诊断中更有用的生物标志物，而t-tau可作为轻度AD前驱状态进展的标志物。由于迄今为止在除AD之外的痴呆症疾病患者中进行的研究数量较少，因此无法对它们在痴呆症鉴别诊断中的有用性做出可靠评估。
