Lombardi V R, García M, Cacabelos R
EuroEspes Biomedical Research Center, Division of Biotechnology, Santa Marta de Babío, La Coruña, Spain.
J Neurosci Res. 1998 Nov 15;54(4):539-53. doi: 10.1002/(SICI)1097-4547(19981115)54:4<539::AID-JNR11>3.0.CO;2-Q.
Several factors that increase the likelihood of developing Alzheimer's disease (AD) have already been identified. A correct evaluation of these may contribute to a better understanding of the etiology of the disease. The risk of developing AD definitely increases with (a) age, (b) head injuries, (c) family history of AD or Down syndrome, (d) sex (higher prevalence of AD in women), (e) vascular disease, (f) exposure to environmental toxins, (g) infectious processes, or (h) changes in immune function, and recent advances in molecular genetics have suggested that genetic predisposition (i) can be considered one of the most important risk factors in the development of AD. A significant increase in the number of amyloid plaques in AD patients with an apolipoprotein E4 (ApoE) allele has been observed and the results of several genetic studies indicate that the etiology of this neurodegenerative disease is associated with the presence of the allele E4 of ApoE. A potential source of damage in the AD brain is an altered response triggered by microglial activation, which is associated with amyloid plaques. It has become evident that a dysregulation of cytokine release appears within lesions of many types of brain disorders including infection, trauma, stroke, and neurodegenerative diseases. Many studies have shown that microglia secrete both cytokines and cytotoxins and since reactive microglia appears in nearly every type of brain damage, it is likely that their secreted products ultimately help to determine the rate of damaged brain tissue. In this study, in vitro cell cultures were established to investigate the effect of different concentrations of human sera (2.5% and 10%) with specific ApoE genotypes from Alzheimer's and non-Alzheimer's subjects on ameboid and flat microglial cells obtained from neonatal rat hippocampi. Results show that a modulation in the proliferation and activation of microglial cells was obtained and that AD sera, mainly in the ApoE 3/4 and 4/4 genotype contain factor(s) which are able to induce morphological changes, as measured by an increase in the ameboid cell type. In addition, major histocompatibility complex (MHC) class II antigen expression, as measured by flow cytometric analysis, and interleukin-1beta (IL-1beta) release as measured by enzyme linked immunoadsorbent assay (ELISA), in comparison with control groups and lipopolysaccharide (LPS)-treated cells, clearly demonstrate a direct effect of ApoE 3/4 and 4/4 and/or an indirect effect mediated by the release of IL-1beta on microglia activation. These results strongly suggest that primary in vitro microglial cell cultures can be used as a screening model to test human sera as well as the effect of new potential drugs aimed at down-regulating microglia activation.
已经确定了几个增加患阿尔茨海默病（AD）可能性的因素。对这些因素进行正确评估可能有助于更好地理解该疾病的病因。患AD的风险肯定会随着以下因素增加：（a）年龄，（b）头部受伤，（c）AD或唐氏综合征的家族病史，（d）性别（女性中AD患病率更高），（e）血管疾病，（f）接触环境毒素，（g）感染过程，或（h）免疫功能变化，并且分子遗传学的最新进展表明遗传易感性（i）可被视为AD发病中最重要的风险因素之一。已观察到携带载脂蛋白E4（ApoE）等位基因的AD患者淀粉样斑块数量显著增加，并且多项遗传学研究结果表明这种神经退行性疾病的病因与ApoE的E4等位基因的存在有关。AD大脑中潜在的损伤来源是由小胶质细胞激活引发的反应改变，这与淀粉样斑块有关。已经很明显，细胞因子释放失调出现在包括感染、创伤、中风和神经退行性疾病在内的多种脑部疾病的病变中。许多研究表明小胶质细胞会分泌细胞因子和细胞毒素，并且由于反应性小胶质细胞几乎出现在每种类型的脑损伤中，它们分泌的产物很可能最终有助于确定脑组织损伤的速度。在本研究中，建立了体外细胞培养体系，以研究来自阿尔茨海默病患者和非阿尔茨海默病患者具有特定ApoE基因型的不同浓度人血清（2.5%和10%）对从新生大鼠海马体获得的阿米巴样和平扁平小胶质细胞的影响。结果表明，小胶质细胞的增殖和激活得到了调节，并且AD血清，主要是ApoE 3/4和4/4基因型的血清，含有能够诱导形态变化的因子，这通过阿米巴样细胞类型的增加来衡量。此外，通过流式细胞术分析测定的主要组织相容性复合体（MHC）II类抗原表达，以及通过酶联免疫吸附测定（ELISA）测定的白细胞介素-1β（IL-1β）释放，与对照组和脂多糖（LPS）处理的细胞相比，清楚地证明了ApoE 3/4和4/4的直接作用和/或由IL-1β释放介导的对小胶质细胞激活的间接作用。这些结果强烈表明，原代体外小胶质细胞培养体系可作为一种筛选模型，用于测试人血清以及旨在下调小胶质细胞激活的新潜在药物的效果。
