科學家新療法讓中年老鼠“重返青春”

自古以來，長生不老就是人類的終極夢想，而生物科技的不斷突破讓我們距離這個夢想越來越近。美國科學家最近用新療法成功讓中年老鼠變年輕，其中面板和腎臟的回春跡象最為明顯。

［Photo/Pexels］

Researchers in the US treated healthy mice with a form of gene therapy that refreshed older cells， making the animals more youthful according to biological markers that are used to measure the effects of ageing。

美國研究人員對健康老鼠實施了一種更新老化細胞的基因療法並獲得成功，透過生物標記法他們測出這些老鼠變年輕了。

Repeating the trick in humans is far from straightforward， but the findings will fuel interest in radical new therapies that aim to slow or reverse the ageing process as a means of tackling age-related diseases such as cancer， brittle bones and Alzheimer’s。

儘管不能用同樣的方法讓人類返老還童，但是這一發現會點燃人們對以延緩或逆轉衰老為目標的激進新療法的興趣，這種療法可以用來治療癌症、骨質疏鬆和老年痴呆症等老年常見疾病。

“A host of age-related diseases might benefit from this approach，” said Heinrich Jasper， a principal fellow and director at the US biotech firm Genentech。

美國生物科技公司基因泰克的首席研究員及主任海因裡希·賈斯珀說：“眾多老年病都可能受益於這種療法。”

The scientists drew on previous work by the Japanese Nobel laureate Prof Shinya Yamanaka， who showed that a mixture of four molecules – known as Yamanaka factors – can rewind adult cells into youthful stem cells that are capable of forming almost any tissue in the body。

美國科學家的這一療法借鑑了日本諾貝爾獎得主山中伸彌教授先前的研究成果。山中伸彌向世人展示，被稱為“山中因子”的四種分子組合在一起可以讓成人細胞逆生長為年輕的幹細胞，而幹細胞可以分化成人體的任何組織。

Writing in the journal Nature Aging， the US team led by Jasper and Prof Juan Carlos Izpisua Belmonte at the Salk Institute in California and the San Diego Altos Institute， found that mice who received Yamanaka factors for several months resembled younger animals in many ways， with their skin and kidneys in particular showing signs of rejuvenation。

來自加州索爾克研究所和聖地亞哥阿爾託斯研究所的賈斯珀和胡安·卡洛斯·依思皮舒·貝爾蒙特教授帶領的美國團隊發現，連續數月注射山中因子的老鼠在很多方面都變得像年輕老鼠，面板和腎臟的回春跡象尤為明顯。該研究發表在《自然-衰老》期刊上。

The experiments showed that rejuvenation was more effective when the therapy was given for a long time – seven to 10 months – starting when the animals were 12 to 15 months old， equivalent to age 35 to 50 in humans。 When older animals， equivalent to 80 years old in human terms， were treated for one month， the scientists saw little impact。

實驗表明，在老鼠12到15個月大（相當於人類35歲到50歲）的時候開始採取這一療法並持續較長時間（7到10個月），回春效果更好。科學家給年長的老鼠（相當於80歲老人）用同樣的方法治療一個月，效果微乎其微。

Researchers are cautious about using Yamanaka factors in humans because previous work has shown that fully reprogrammed cells can turn into clumps of cancerous tissue called teratomas。

山中伸彌先前的研究顯示，經過完全基因重組的細胞會轉變為癌組織畸胎瘤，因此科學家還不敢輕易給人類注射山中因子。

The latest study shows that partial reprogramming may be able to rejuvenate tissues without such risks， but further hurdles remain。 Rather than using Yamanaka factors to rejuvenate aged humans， many scientists suspect that new drugs will be needed to partially reprogram cells safely and effectively。

儘管這項新研究表明，部分重組的細胞或許可以在避免這一風險的情況下更新細胞組織，但是實施起來還是障礙重重。許多科學家認為，需要研發新藥物才能安全有效地對細胞進行部分重組，而不能直接用山中因子來讓人類返老還童。

”In theory， biological age reversal or reduction could be possible。 However， we are at very early stages where we need to understand the basic science behind it much better，“ said Dr Tamir Chandra， an expert in the biology of ageing at the University of Edinburgh， who was not involved in the study。

沒有參與該研究的愛丁堡大學衰老生物學專家塔米爾·錢德拉博士說：“理論上，逆齡生長或延緩衰老是可能實現的。但是，我們現在還處於這一研究領域的初級階段，我們需要更好地瞭解這背後的基礎科學。”

英文來源：衛報

翻譯&編輯：丹妮