阿茲海默症（Alzheimer's disease）是一種漸進式的神經退化性疾病。主要的病理特徵有貝他糊蛋白斑塊沈澱於細胞外及神經纖維糾結聚集於神經細胞內。貝他糊蛋白斑塊最主要的成份是貝他糊蛋白；係由細胞膜上的前趨蛋白經由酵素切割而成。在腦中，貝他糊蛋白可能與其他蛋白結合，導致其加速聚集或減弱被代謝的可能。血紅素（Hemoglobin）是一種被研究許久的球蛋白，其在人體最重要的功能是在紅血球中攜帶氧氣。先前的研究發現，血紅素出現在類澱粉蛋白斑塊的沈積中，也發現血紅素可與貝他糊蛋白結合。然而儘管血紅素可以在阿茲海默氏症患者的血漿與腦組織和貝他糊蛋白一起分離出來，這些血紅素是來自血管中的紅血球，或者是腦中的細胞卻無法確認。有研究指出腦中細胞可以表現血紅素，然而由何種細胞所表現卻仍不清楚。本研究的目的是探討血紅素對貝他糊蛋白聚集的影響，並找出哪些腦內細胞會生成血紅素。首先，以試管中加入血紅素與貝他糊蛋白培養發現，血紅素不但能夠依量促進貝他糊蛋白的聚集，也會隨培養時間增加，依時促進貝他糊蛋白的聚集。然而，在電子顯微鏡底下，貝他糊蛋白的纖維化並不受血紅素影響。在人類腦組織切片中，血紅素會出現在顳葉的寡突細胞細胞本體和神經元細胞質中。其中尤其是寡突細胞—幾乎所有的寡突細胞細胞本體都有血紅素的存在。此外，極少數的星狀細胞與微膠細胞(<5%)也表現有血紅素。總結本研究顯示，血紅素只在貝他糊蛋白聚集的初期有促進作用；大腦中主要表現血紅素的細胞是寡突細胞和神經元。

Alzheimer’s disease (AD) is an age-related neurodegenerative disorder characterized pathologically by the presence of extracellular senile plaques and intraneuronal neurofibrillary tangles. The main component of senile plaques is the β-amyloid (Aβ) peptides derived from the larger precursor protein, AβPP. It has been postulated that binding of some molecules to Aβ are responsible for the promotion of accumulation or increase of stability of amyloid in AD. Hemoglobin (Hb), is the oxygen- and carbon dioxide-carrying protein responsible for oxygen delivery to the tissues. Previously, Hb was identified as a potent Aβ binding protein and found to be co-localized with Aβ in amyloid plaques and cerebral amyloid angiopathy. Though Hb has been co-immunoprecipitated with Aβ from both AD brains and plasma, whether Hb is derived from circulation or from brain cells remain elusive. The objective of this study is to characterize the possible role of Hb on Aβ aggregation and the expression of Hb in the brain. In vitro studies showed that the Hb promoted Aβ aggregation in a time and dose dependent manner. However, under the electron microscopy, Hb did not alter the fibrilization of Aβ Hb immunoreactivity was found in a subpopulation of hippocampal and cortical neurons in human postmortem temporal lobe. Among them, Hb expressed in the cell bodies of almost all the oligodendrocytes. Hb immunoreactivity was also evident in neuronal cell, although to a lesser degree. Occasionally, Hb immunoreactivity could be found in a very limited number of astrocytes and microglia. Taken together, these studies suggest that Hb promotes the initial phase of Aβ oligomerization, but not the later polymerization phase. Hb is primarily expressed in the oligodendrocyte and neuron.

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