Balin B J, Gérard H C, Arking E J, Appelt D M, Branigan P J, Abrams J T, Whittum-Hudson J A, Hudson A P
Department of Pathology and Laboratory Medicine, MCP-Hahnemann School of Medicine, Allegheny University of the Health Sciences, Philadelphia, PA 19102, USA.
Med Microbiol Immunol. 1998 Jun;187(1):23-42. doi: 10.1007/s004300050071.
We assessed whether the intracellular bacterium Chlamydia pneumoniae was present in post-mortem brain samples from patients with and without late-onset Alzheimer's disease (AD), since some indirect evidence seems to suggest that infection with the organism might be associated with the disease. Nucleic acids prepared from those samples were screened by polymerase chain reaction (PCR) assay for DNA sequences from the bacterium, and such analyses showed that brain areas with typical AD-related neuropathology were positive for the organism in 17/19 AD patients. Similar analyses of identical brain areas of 18/19 control patients were PCR-negative. Electron- and immunoelectron-microscopic studies of tissues from affected AD brain regions identified chlamydial elementary and reticulate bodies, but similar examinations of non-AD brains were negative for the bacterium. Culture studies of a subset of affected AD brain tissues for C. pneumoniae were strongly positive, while identically performed analyses of non-AD brain tissues were negative. Reverse transcription (RT)-PCR assays using RNA from affected areas of AD brains confirmed that transcripts from two important C. pneumoniae genes were present in those samples but not in controls. Immunohistochemical examination of AD brains, but not those of controls, identified C. pneumoniae within pericytes, microglia, and astroglia. Further immunolabelling studies confirmed the organisms' intracellular presence primarily in areas of neuropathology in the AD brain. Thus, C. pneumoniae is present, viable, and transcriptionally active in areas of neuropathology in the AD brain, possibly suggesting that infection with the organism is a risk factor for late-onset AD.
我们评估了胞内细菌肺炎衣原体是否存在于患有和未患迟发性阿尔茨海默病（AD）患者的尸检脑样本中，因为一些间接证据似乎表明该病原体感染可能与该病有关。通过聚合酶链反应（PCR）检测对从这些样本中提取的核酸进行筛查，以寻找该细菌的DNA序列，此类分析显示，在19例AD患者中，具有典型AD相关神经病理学特征的脑区对该病原体呈阳性反应。对19例对照患者相同脑区进行的类似分析，PCR结果为阴性。对AD病脑受累区域组织进行的电子显微镜和免疫电子显微镜研究鉴定出了衣原体的原体和网状体，但对非AD病脑进行的类似检查未发现该细菌。对一部分AD病脑受累组织进行肺炎衣原体培养研究，结果呈强阳性，而对非AD病脑组织进行的相同分析则为阴性。使用来自AD病脑受累区域的RNA进行逆转录（RT）-PCR检测证实，在这些样本中存在肺炎衣原体两个重要基因的转录本，而在对照样本中则未检测到。对AD病脑而非对照脑进行免疫组织化学检查，在周细胞、小胶质细胞和星形胶质细胞内鉴定出肺炎衣原体。进一步免疫标记研究证实，该病原体主要存在于AD病脑的神经病理学区域内。因此，肺炎衣原体存在于AD病脑的神经病理学区域，具有活性且转录活跃，这可能表明该病原体感染是迟发性AD的一个风险因素。
