Center for Brain Research, Medical University of Vienna, Vienna, Austria.
Acta Neuropathol. 2011 Sep;122(3):271-83. doi: 10.1007/s00401-011-0836-9. Epub 2011 May 19.
In Alzheimer's disease (AD), lipid alterations are present early during disease progression. As some of these alterations point towards a peroxisomal dysfunction, we investigated peroxisomes in human postmortem brains obtained from the cohort-based, longitudinal Vienna-Transdanube Aging (VITA) study. Based on the neuropathological Braak staging for AD on one hemisphere, the patients were grouped into three cohorts of increasing severity (stages I-II, III-IV, and V-VI, respectively). Lipid analyses of cortical regions from the other hemisphere revealed accumulation of C22:0 and very long-chain fatty acids (VLCFA, C24:0 and C26:0), all substrates for peroxisomal β-oxidation, in cases with stages V-VI pathology compared with those modestly affected (stages I-II). Conversely, the level of plasmalogens, which need intact peroxisomes for their biosynthesis, was decreased in severely affected tissues, in agreement with a peroxisomal dysfunction. In addition, the peroxisomal volume density was increased in the soma of neurons in gyrus frontalis at advanced AD stages. Confocal laser microscopy demonstrated a loss of peroxisomes in neuronal processes with abnormally phosphorylated tau protein, implicating impaired trafficking as the cause of altered peroxisomal distribution. Besides the original Braak staging, the study design allowed a direct correlation between the biochemical findings and the amount of neurofibrillary tangles (NFT) and neuritic plaques, quantified in adjacent tissue sections. Interestingly, the decrease in plasmalogens and the increase in VLCFA and peroxisomal volume density in neuronal somata all showed a stronger association with NFT than with neuritic plaques. These results indicate substantial peroxisome-related alterations in AD, which may contribute to the progression of AD pathology.
在阿尔茨海默病（AD）中，脂质改变在疾病进展的早期就存在。由于其中一些改变指向过氧化物酶体功能障碍，我们研究了来自基于队列的纵向维也纳-多瑙河衰老（VITA）研究的人类死后大脑中的过氧化物酶体。根据 AD 的神经病理学 Braak 分期，将患者分为三个严重程度递增的队列（分别为 I-II 期、III-IV 期和 V-VI 期）。对另一个半球的皮质区域进行脂质分析，发现与轻度受累（I-II 期）相比，V-VI 期病理患者的 C22:0 和超长链脂肪酸（VLCFA，C24:0 和 C26:0）积累，所有这些都是过氧化物体β-氧化的底物。相反，对于严重受累的组织，需要完整的过氧化物体来合成的质体，其水平降低，这与过氧化物体功能障碍一致。此外，在 AD 晚期，额回神经元体中的过氧化物体体积密度增加。共聚焦激光显微镜显示，在异常磷酸化 tau 蛋白的神经元突起中过氧化物体丢失，提示运输受损是过氧化物体分布改变的原因。除了原始的 Braak 分期外，研究设计还允许将生化发现与神经原纤维缠结（NFT）和神经突斑块的数量进行直接关联，这些在相邻的组织切片中进行定量。有趣的是，神经元体中质体的减少以及 VLCFA 和过氧化物体体积密度的增加与 NFT 的相关性均强于与神经突斑块的相关性。这些结果表明 AD 中存在大量与过氧化物体相关的改变，这可能导致 AD 病理的进展。
