研究人员称病毒有助于治疗阿尔茨海默病

Researchers: Viruses May Help Cause Alzheimer’s Disease

Viruses that hide in the brain might influence Alzheimer’s disease. That is what researchers said in a new study that is expected to restart debate about what causes the brain-wasting disease.

However, the findings do not prove viruses cause Alzheimer’s. They also do not suggest that it can be passed from one person to another.

A team led by researchers at New York’s Mount Sinai Health System found that some viruses affect genes¹ involved in Alzheimer’s. Among those genes are two very common herpes viruses.

The idea that infections earlier in life might somehow begin the process of getting Alzheimer’s years later has been discussed for years. But the theory that Alzheimer’s starts from sticky plaques³ that clog⁴ the brain has had more support.

The study has some specialists saying it is time to look more closely at viruses. This is because of the failure of attempts to prevent the plaques.

Dr. John Morris directs the Alzheimer’s research center at Washington University School of Medicine in St. Louis. He said, “With an illness this terrible, we cannot afford to dismiss all scientific possibilities.” Morris was not involved in the new research.

Dr. Rudolph Tanzi is an Alzheimer’s specialist at Massachusetts General Hospital. He said the study also agrees with growing evidence that the brain’s ability to defend itself against viruses may be riskier⁵ than an actual infection.

Tanzi was not involved in the recent study but has performed related experiments with Dr. Robert Moir of Harvard. Their research has shown that sticky beta-amyloid plaque² captures germs by completely surrounding them. The researchers say that is why the plaque starts forming in the brain.

“The question remained, OK, in the Alzheimer brain what are the microbes that matter, what are the microbes that start the plaque?” said Tanzi.

The team from Mount Sinai and Arizona State University found some viral suspects — by accident. Their study was not hunting viruses. It was looking for new drugs that would target Alzheimer’s.

The researchers were using complex genetic⁶ information from hundreds of brains. They wanted to compare differences between people who had died with Alzheimer’s and people who had died completely free of Alzheimer’s.

The possibility that viruses were around “came screaming out at us,” said Mount Sinai genetic expert Joel Dudley. He was a leading author of the research published in the journal Neuron.

The team found viral genetic material at far higher levels in the brains of people with Alzheimer’s than in normal brains. Two human herpes viruses, known as HHV6a and HHV7, stood out. They infect most people during childhood, often with no symptoms, and then lie inactive in the body.

Since 1980, researchers have known that some common bacteria and viruses increased the likelihood of getting Alzheimer’s. But it was never clear if the germs were bystanders, or actively⁷ adding to the development of Alzheimer’s.

The new study used computer models to see how the viral genes intervened in human genes, proteins and plaque buildup.

They found a lot of interactions, suggesting that the viruses could even switch Alzheimer’s-related genes on and off. To see if those interactions mattered, the researchers created mice that lack one molecule⁸ that the herpes virus seemed to destroy. The animals, researchers said, developed more of the amyloid plaques.

Keith Fargo directs scientific programs for the Alzheimer’s Association. He said the research makes a viral connection to Alzheimer’s much more possible.

But, he noted⁹, the study will not affect how today’s Alzheimer’s patients are treated.

The National Institutes of Health (NIH) supported the study. The NIH is now giving money for a new study to see if an antiviral drug can help people who have both mild Alzheimer’s and different herpes viruses.

Just having a herpes virus “does not mean you’re going to get Alzheimer’s,” Tanzi said. It may not even have gotten into the brain.

But Tanzi added, “The brain was always thought to be a sterile¹⁰ place. That’s absolutely not true.”

I’m Susan Shand. And I'm Alice Bryant.

Words in This Story

herpes- n. a disease that causes painful spots on the ski

plague – n. a change in brain tissue that occurs in Alzheimer's disease

clog – v. to slowly form a block in (something, such as a pipe or street) so that things cannot move through quickly or easily

impressive - adj. deserving attention, admiration¹¹, or respect

scream – v. to shout loudly

symptoms –n. a change that shows that a disease is present

bystander – n. someone who is uninvolved in an incident but comes to watch the police or ambulance

microbe – n. an extremely small living thing that can only be seen with a microscope

1 genes   

n.基因( gene的名词复数 )

参考例句：

• You have good genes from your parents, so you should live a long time. 你从父母那儿获得优良的基因，所以能够活得很长。 来自《简明英汉词典》
• Differences will help to reveal the functions of the genes. 它们间的差异将会帮助我们揭开基因多种功能。 来自英汉非文学 - 生命科学 - 生物技术的世纪

2 plaque   

n.饰板，匾，(医)血小板

参考例句：

• There is a commemorative plaque to the artist in the village hall.村公所里有一块纪念该艺术家的牌匾。
• Some Latin words were engraved on the plaque. 牌匾上刻着些拉丁文。

3 plaques   

（纪念性的）匾牌( plaque的名词复数 )； 纪念匾； 牙斑； 空斑

参考例句：

• Primary plaques were detectable in 16 to 20 hours. 在16到20小时内可查出原发溶斑。
• The gondoliers wore green and white livery and silver plaques on their chests. 船夫们穿着白绿两色的制服，胸前别着银质徽章。

4 clog   

vt.塞满，阻塞；n.[常pl.]木屐

参考例句：

• In cotton and wool processing,short length fibers may clog sewers.在棉毛生产中，短纤维可能堵塞下水管道。
• These streets often clog during the rush hour.这几条大街在交通高峰时间常常发生交通堵塞。

5 riskier   

冒险的，危险的( risky的比较级 )

参考例句：

• Now they are starting to demand higher returns on riskier assets. 而今他们开始在风险更高的资产上要求更高的回报。
• The problem with that: RIM's business is getting riskier every quarter. 不过问题也随之而来：RIM面临的业务风险正逐季增大。

6 genetic   

adj.遗传的，遗传学的

参考例句：

• It's very difficult to treat genetic diseases.遗传性疾病治疗起来很困难。
• Each daughter cell can receive a full complement of the genetic information.每个子细胞可以收到遗传信息的一个完全补偿物。

7 actively   

adv.积极地，勤奋地

参考例句：

• During this period all the students were actively participating.在这节课中所有的学生都积极参加。
• We are actively intervening to settle a quarrel.我们正在积极调解争执。

8 molecule   

n.分子，克分子

参考例句：

• A molecule of water is made up of two atoms of hygrogen and one atom of oxygen.一个水分子是由P妈̬f婘̬ 妈̬成的。
• This gives us the structural formula of the molecule.这种方式给出了分子的结构式。

9 noted   

adj.著名的，知名的

参考例句：

• The local hotel is noted for its good table.当地的那家酒店以餐食精美而著称。
• Jim is noted for arriving late for work.吉姆上班迟到出了名。

10 sterile   

adj.不毛的，不孕的，无菌的，枯燥的，贫瘠的

参考例句：

• This top fits over the bottle and keeps the teat sterile.这个盖子严实地盖在奶瓶上，保持奶嘴无菌。
• The farmers turned the sterile land into high fields.农民们把不毛之地变成了高产田。

11 admiration   

n.钦佩，赞美，羡慕

参考例句：

• He was lost in admiration of the beauty of the scene.他对风景之美赞不绝口。
• We have a great admiration for the gold medalists.我们对金牌获得者极为敬佩。