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[经济学人] 老年痴呆新疗法

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发表于 2023-11-29 01:46:59 | 显示全部楼层 |阅读模式

老年痴呆新疗法(上)
One of the first signs of Alzheimer's disease is confusion.
阿尔茨海默病的最初症状之一是神志不清。
Most people can park their car in a different space every morning and find it again in the evening.
大多数人可以每天早上把车停在不同的地方,晚上再找到它。
Those with Alzheimer's find this type of problem much harder.
那些患有老年痴呆症的人会发现这类问题要困难得多。
Memories of things they do often, like eating or taking medication, become tangled in their minds.
他们记忆中经常做的事情,比如吃饭或服药,在脑海中变得纠结复杂。
The ability to distinguish between similar memories depends on a tiny strip of brain tissue called the dentate gyrus.
区分相似记忆的能力依赖于一小块被称为齿状回的脑组织。
Studies in mice have shown that the dentate gyrus is one of the few bits of the brain to generate new neurons even in adulthood.
对老鼠的研究表明,即使在成年后,齿状回也是大脑中少数几个会产生新神经元的部位之一。
Those new neurons are thought to help keep similar memories distinct.
这些新的神经元被认为有助于保持相似记忆的区别。
Whether something similar happens in humans is less clear.
尚不清楚人类是否也会发生类似的情况。
But a clutch of new results described this week at the Society for Neuroscience's conference in Washington, dc, suggest that it might.
但本周在华盛顿举行的神经科学学会会议上公布的一系列新结果表明,答案可能是肯定的。
And if it does, then encouraging the process might offer a new treatment for Alzheimer's disease.
如果确实如此,那么促进这个过程可能会为阿尔茨海默病提供一种新的治疗方法。
Until the 1960s scientists thought adult brains did not produce new neurons.
直到20世纪60年代,科学家们都认为成年人的大脑不会产生新的神经元。
Then evidence began to emerge of young neurons in the brains of adult rats and mice,-specifically in the olfactory bulb, which processes smell, and the dentate gyrus.
随后,成年大鼠和小鼠的大脑中出现了年轻神经元的证据,特别是在处理气味的嗅球和齿状回中。
These new neurons had developed from neural progenitor cells, a type of undifferentiated neuron akin to a stem cell, in a process scientists call neurogenesis.
这些新神经元是从神经祖细胞(一种类似于干细胞的未分化神经元)发育而来的,科学家们将这一过程称为神经发生。
And there seems to be a link, at least in mice, between these new neurons and Alzheimer's disease.
至少在老鼠身上,这些新神经元和阿尔茨海默病之间似乎存在联系。
Mice genetically engineered to have Alzheimer's-like symptoms also have fewer young neurons in their brains.
经过基因改造后出现类似阿尔茨海默病症状的老鼠,大脑中年轻的神经元也更少了。
Two studies published in 2021 and 2022 showed that encouraging neurogenesis could improve memory in such animals.
2021年和2022年发表的两项研究表明,促进神经发生可以改善这些动物的记忆力。
And a paper published in April this year found that boosting neurogenesis also caused other cells known as microglia to begin cleaning up tangles of protein, called amyloid-beta plaques, that are characteristic of Alzheimer's disease.
今年4月发表的一篇论文发现,促进神经发生也会导致其他小胶质细胞,开始清理淀粉样蛋白斑块的蛋白质缠结,这是阿尔茨海默病的特征。
So far so promising-if you are a mouse.
到目前为止,一切都很有希望——如果你是一只老鼠的话。
But studying neurogenesis in humans is tricky.
但是研究人类的神经发生是很棘手的。
MRI scanners cannot watch the growth of individual neurons.
核磁共振扫描仪不能观察单个神经元的生长。
Scientists must take samples of brain tissue from cadavers and either stain them with chemicals that bind only to young neurons, or measure the genes that have been expressed within brain cells to look for the hallmarks of youth.
科学家们必须从尸体上采集脑组织样本,要么用只与年轻神经元结合的化学物质染色,要么测量脑细胞中表达的基因,以寻找年轻神经元的特征。
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 楼主| 发表于 2023-11-29 01:47:49 | 显示全部楼层

老年痴呆新疗法(下)
Dozens of such papers have been published.
这样的论文已经发表了几十篇。
But for every one that has found evidence of neurogenesis, another has failed to do so.
但是,与每一个发现了神经发生证据的人相比,另一个群体却一无所获。
The pro-neurogenesis camp thinks the null results are down to poor-quality brain tissue or crude preservation techniques.
支持神经发生的阵营认为,无效的结果是由于脑组织质量差或保存技术粗糙。
The antis argue that either humans do not grow these neurons in the dentate gyrus, or if they do, there are too few of them to be useful.
反对者认为,要么人类在齿状回中不生长这些神经元,要么即使生长了,它们也太少了,无法发挥作用。
The research presented in Washington strengthens the case for human neurogenesis.
在华盛顿发表的这项研究为人类神经发生的观点提供了更有力的理由。
Maura Boldrini of Columbia University, María Llorens-Martín of the University of Madrid, Orly Lazarov at the University of Illinois at Chicago and Hongjun Song of the University of Pennsylvania presented evidence of young neurons in the dentate gyruses of humans-though most of their findings have not yet been peer reviewed.
哥伦比亚大学的莫拉·宝尔德里尼、马德里大学的玛丽亚·伦斯-马丁、芝加哥伊利诺伊大学的奥利·拉扎洛夫 和宾夕法尼亚大学的弘隽·宋提出了人类齿状回中存在年轻神经元的证据——尽管他们的大部分发现尚未经过同行评审。
Three of these researchers also studied the brains of healthy older people or people with Alzheimer's disease.
其中三名研究人员还研究了健康老年人或阿尔茨海默病患者的大脑。
Their results suggested that the production of the supposed new neurons slows with age, and falls precipitously in Alzheimer's disease.
他们的研究结果表明,所谓的新神经元的产生随着年龄的增长而逐渐减缓,在患上老年痴呆症后急剧下降。
Previous studies by two of the groups also found that Alzheimer's patients with more of these neurons had better memories.
其中两组先前的研究还发现,拥有更多这些神经元的阿尔茨海默病患者记忆力更好。
But while the new research strengthens the case for human neurogenesis, it is not yet definitive.
但是,虽然这项新研究为人类神经发生的案例提供了更有力的理由,但它还不是决定性的。
One group of researchers from Yale University questioned whether the staining technique used in one of the studies was accidentally tagging other brain cells such as astrocytes.
耶鲁大学的一组研究人员质疑,在其中一项研究中使用的染色技术是否意外地标记了其他脑细胞,如星形胶质细胞。
They are also concerned that the studies tend to find very few progenitor cells.
他们还担心,这些研究往往只能发现很少的祖细胞。
"Where are all the mothers of these baby neurons? " asked Jon Arellano, one of the sceptics.
“这些小神经元的母细胞在哪里?”怀疑论者之一的乔恩·阿雷利亚诺问道。
There are other wrinkles.
还出现了其他小问题。
Dr Song found a different set of genes expressed in the supposedly young human neurons from those seen in neurons from other animals.
宋博士发现,在被认为是年轻的人类神经元中表达的一组基因,与其他动物神经元中的表达形式不同。
And the few young neurons that both Dr Song and Dr Lazarov found in the brains of Alzheimer's patients looked very different from the same neurons in healthy brains.
宋博士和拉扎罗夫博士在阿尔茨海默病患者的大脑中发现的少数年轻神经元与健康大脑中的相同神经元看起来非常不同。
If the new cells are somehow defective, increasing their number may not help.
如果新细胞有某种缺陷,增加它们的数量可能无济于事。
But although not all the scientists at the conference were convinced, some drug-makers appear to be.
但是,尽管不是所有参加会议的科学家都相信这一观点,一些制药商似乎是相信的。
In April, Biomed Industries, a pharmaceutical firm based in California, said that results from an early clinical trial suggested that a new drug that the firm claims increases neurogenesis in mice improved memory in people with moderate Alzheimer's.
今年4月,总部位于加州的制药公司生物医药实业公司称,他们的一项早期临床试验的结果表明,有一种能促进小鼠神经发生的新药,同时也改善了中度阿尔茨海默氏症患者的记忆力。
If subsequent trials prove to be equally encouraging, that could be further evidence that the neurogenesis theory of Alzheimer's may indeed have something to it.
如果后续的试验结果同样令人鼓舞,那将进一步证明阿尔茨海默氏症的神经发生理论可能确实前途无量。
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