Today, tomorrow, learn English naturally. 天天自然学英语
Common Sleeping Pill May Reduce The Build-Up of Alzheimer's Proteins, Study Finds
There's still so much we don't know about Alzheimer's disease, but the link between poor sleep and worsening disease is one that researchers are exploring with gusto.
Now, a new study has found that using sleeping pills to get some shut-eye could reduce the build-up of toxic clumps of proteins in fluid that washes the brain clean every night.
Researchers from Washington University in St. Louis found people who took suvorexant, a common treatment for insomnia, for two nights at a sleep clinic experienced a slight drop in two proteins, amyloid-beta and tau, that pile up in Alzheimer's disease.
Though only short and involving a small group of healthy adults, the study is an interesting demonstration of the link between sleep and the molecular markers of Alzheimer's disease.
Sleep disturbances can be an early warning sign of Alzheimer's disease that precedes other symptoms, such as memory loss and cognitive decline. And by the time the first symptoms develop, levels of abnormal amyloid-beta are almost peaking, forming clumps called plaques that clog up brain cells.
Researchers think promoting sleep could be one avenue to stave off Alzheimer's disease, by allowing the sleeping brain to flush itself of leftover proteins and the day's other waste products.
While sleeping pills may help in that regard, "it would be premature for people who are worried about developing Alzheimer's to interpret it as a reason to start taking suvorexant every night," says neurologist Brendan Lucey, of Washington University's Sleep Medicine Center, who led the research.
The study spanned just two nights and involved 38 middle-aged participants who showed no signs of cognitive impairment and had no sleep issues.
Using sleeping pills for prolonged periods is not an ideal solution for those short on sleep either, as it's quite easy to become dependent on them.
Sleeping pills may also lull people into shallower bouts of sleep rather than deep sleep phases. This could be problematic as earlier research from Lucey and colleagues found a link between less good quality, slow-wave sleep and elevated levels of tau tangles and amyloid-beta protein.
In their latest study, Lucey and colleagues wanted to see if improving sleep with the aid of sleeping pills could lower levels of tau and amyloid-beta in the cerebrospinal fluid that bathes the brain and spinal cord. Past research shows that even just one night of disrupted sleep can send amyloid-beta levels rising.
A group of volunteers aged 45 to 65 years old received one of two doses of suvorexant or a placebo pill, an hour after researchers tapped their cerebrospinal fluid to collect a small sample.
The researchers continued to collect samples every two hours for 36 hours while the participants slept and during the next day and night, to measure how protein levels changed.
There were no differences in sleep between the groups, and yet amyloid-beta concentrations were reduced by between 10 and 20 percent with a dose of suvorexant usually prescribed for insomnia, compared to a placebo.
The higher dose of suvorexant also momentarily reduced levels of hyperphosphorylated tau, a modified form of the tau protein linked to the formation of tau tangles and cell death.
However, this effect was only seen with some forms of tau, and tau concentrations sprung back up within 24 hours of taking the sleeping pill.
"If you can reduce tau phosphorylation, potentially there would be less tangle formation and less neuronal death," explains Lucey, still hopeful that future studies in older adults testing sleeping pills for months could possibly measure a lasting effect on protein levels (whilst noting any downsides of sleeping pills).
Of course, this all rests on our understanding of what causes Alzheimer's disease.
The leading theory, that abnormal protein clumps drive Alzheimer's pathology, has come under intense scrutiny lately after decades of research aimed at lowering amyloid levels has not translated into any useful drug or therapy that actually prevents or slows the disease. This has prompted researchers to rethink how Alzheimer's disease develops.
In other words, sleeping pills may help some people get some shut-eye but using them as a preventative treatment to ward off Alzheimer's disease is still a hazy prospect that hangs on a now-shaky hypothesis of Alzheimer's pathology.
That said, there is increasing evidence linking sleep disturbances to Alzheimer's disease, a disease for which no treatments exist. Lucey says improving sleep hygiene and seeking treatment for sleep problems such as sleep apnea are both sensible approaches to improving general brain health at any age.
"I'm hopeful that we will eventually develop drugs that take advantage of the link between sleep and Alzheimer's to prevent cognitive decline," says Lucey. But he admits, "We're not quite there yet."
注释：
gusto: n
表示"嗜好；"，means "vigorous and enthusiastic enjoyment"，如：He started painting with great gusto. 他兴致勃勃地开始作画。
suvorexant: n
表示"苏沃雷生片Belsomra(Suvorexant)用于治疗失眠症。"，
amyloid: n; adj
1. n表示"淀粉体"，means "a non-nitrogenous food substance consisting chiefly of starch;"，如：Amyloid beta is a shape-changing chameleon. 淀粉状蛋白是一种形状经常改变的蛋白。
2. adj表示"淀粉体的"，means "resembling starch"，如：Amyloid deposits were positive for Congo Red(15/15). 淀粉样沉积物刚果红染色阳性(15/15)。
tau：n
表示" 希腊文的第19个字母"，means "the 19th letter of the Greek alphabet"
molecular: adj
表示" 分子的"，means "relating to or produced by or consisting of molecules"，如：It can also perform molecular dynamics simulations.它能也执行分子的动力学模拟。
plaque: n
表示"饰板;【医】血小板；【医】斑"，means "a memorial made of brass；(pathology) a small abnormal patch on or inside the body"，如：A bronze plaque marks the house where the poet was born.一块铜匾标示出诗人诞生的那所房子。Scientists have found a compound in the fruit can stop bacteria from clinging to the teeth, blocking the formation of damaging plaque deposits.科学家在这种水果中发现一种化合物，可以阻止细菌黏附在牙齿上，防止破坏性齿菌斑沉淀物的形成。
stave：v
表示"避开；"，means "furnish with staves"，如：Bailouts amount to mortgaging the future to stave off the wolf howling at the door. 紧急援助意味着为了避开正在门口嚎叫的野狼而将未来抵押出去。
impairment: n
表示" 损伤"，means "the condition of being unable to perform as a consequence of physical or mental unfitness;"，如：She did not have any evidence of hearing impairment. 她没有任何听力损害的证据。
lull: n; v
1. n表示"间歇，暂停"，means "a pause during which things are calm or activities are diminished"，如：This is just the lull before the storm. 这只是暴风雨前的暂时平静。
2. v表示" 使安静；使入睡；哄骗"，means "make quiet or calm with gentle sound"，如：The mother lulled the baby to sleep.母亲哄着孩子入睡了。They lulled me into a false sense of security. 他们哄骗我，让我产生了一种虚假的安全感。
bout: n
表示" 回合；一场；"，means "contest or struggle (especially a boxing match)"，如：There are three rounds in an amateur boxing bout. 一场业余拳击比赛打三个回合。
tangle: n
表示"纠纷;纠缠；混乱"，means "something jumbled or confused"，如：We employed a lawyer to straighten our legal tangle.我们雇了一位律师把法律纠纷理出头绪。
cerebrospinal：adj
表示"脑脊髓的"，means "of or relating to the brain and spinal cord"，如：It is covered by the meninges and cushioned by cerebrospinal fluid. 外覆脑膜受脑脊液保护。
placebo: n
表示" 安慰剂；"，means "an innocuous or inert medication; "，如：The placebo has been found to work with a lot of different cases.人们已发现安慰剂能在很多不同的病例中发挥作用。
scrutiny: n
表示" 监视；细看；"，means "careful and thorough examination"，如：She was conscious of his scrutiny of her face. 她觉察到了他长时间的注视着她的脸。
pathology: n
表示" 病理学"，means "the branch of medical science that studies the causes and nature and effects of diseases"，如：Pathology is the study of disease. 病理学是研究疾病的科学。
apnea: n
表示" 呼吸暂停；窒息"，means "transient cessation of respiration"，如：Obesity is a major risk factor for sleep apnea. 肥胖是呼吸暂停的主要危险因素。
中文简要说明：
高龄化的问题，使得我们更关心老人病，俗称失智症的阿兹海默症(Alzheimer's disease,AD)更是特别关注。不过关于此症，我们仍然知之甚少，只能不断的探索。最近的研究认为，睡眠不足与失智症恶化有关连，或许良好的睡眠，可以清除那大脑内的有毒蛋白斑块。
科学警报(ScienceAlert)报导，圣路易华盛顿大学(Washington University in St. Louis)的研究人员发现，在睡眠诊所服用2天的舒沃瑞森(suvorexant,台湾还未上市)，受试者脑部的两种有害蛋白质（β-淀粉样蛋白和𝜏蛋白）略有下降，这两种变性蛋白，是失智症的一种明确现象。
虽然这项研究的时间很短，并且参与实验的是健康的成年人，但是这项研究，也证明了睡眠与阿兹海默症状特征的联系。
研究人员在几年前发现，睡眠障碍可能是失智症早期警讯，优先于其他更明确的症状，比如记忆力减退和认知能力下降。事实上，要是出现记忆减退时，患者的脑部类淀粉样蛋白-β 已经堆积的颇为严重了，形成斑块，堵塞脑细胞。
因此研究人员认为，睡眠的过程，可能是大脑自行清除那些异变蛋白的时间，同时也清除其他脑细胞产生的废物，大脑也就保持健康，避免阿兹海默症的出现。
虽然安眠药在这方面可能有所帮助，但华盛顿大学睡眠医学中心的神经学家路西(Brendan Lucey)说：「现不能说舒沃瑞森是预防阿兹海默症的用药，一切还为时过早。」
对于睡眠不足的人来说，长期服用安眠药也不是理想的解决方案，因为很容易对它们产生依赖。而且安眠药也可能只在浅眠的效果，而睡眠质量较差的浅眠，对于清理淀粉样蛋白的效率也不高。
说一下研究方法。一组年龄在 45~65 岁之间的志愿者，接受了两剂舒沃瑞森，有些人只服用安慰剂，在一小时后，参与者睡着后，研究人员采集他们的脑脊液，每2小时调查一次。并在接下来的白天和晚上也会调查，测量蛋白的变化。
两组之间的睡眠没有差异，但与安慰剂相比，服用舒沃瑞森的实验组，β 类淀蛋白浓度降低了10~20%。
留言微信公众号《自然学英语LearnNaturally》，可咨询更多!