The quest to keep organs alive outside the body

让器官在体外存活的探索

EXECUTIVE SUMMARY This week, I covered a fascinating effort to preserve organs outside the body. There’s a huge shortage of donor organs, and one of the main reasons is time—they survive only a matter of hours outside the body, even when they’re kept on ice. Doctors dream of organ banks—stores of human organs that can be preserved for days, weeks, months, or even longer. That would allow them to run tests on organs, find the best matches for them, and transport the organs to those recipients.

执行摘要 本周，我报道了一项关于在体外保存器官的迷人研究。目前捐赠器官严重短缺，主要原因之一是时间限制——即使放在冰上，器官在体外也只能存活几个小时。医生们梦想着建立“器官银行”，即可以保存数天、数周、数月甚至更长时间的人体器官库。这将使他们能够对器官进行测试、寻找最佳匹配，并将器官运送给受体。

In new research, one team has been able to supercool the kidneys of pigs—animals whose organs are of a similar size to human ones—and preserve them for days. The kidneys survived being stored at −4 °C (25 °F) and eventually reimplanted back into pigs. And that’s just the latest development in a field that is positively buzzing.

在最新的研究中，一个团队成功地对猪的肾脏进行了“过冷”处理（猪的器官大小与人类相似），并将其保存了数天。这些肾脏在 -4°C (25°F) 的环境下成功存活，并最终被重新植入猪体内。这只是该领域最新进展的一个缩影，目前这一领域正处于蓬勃发展之中。

It has proved super difficult to freeze organs. Once ice forms in them, they’re done. The ice crystals create all kinds of damage and render the organs unusable. That hasn’t stopped many researchers from trying. Some have focused on cryopreservation—rapid extreme cooling that essentially leaves cells in a glasslike state. This process is now routine for eggs, sperm, and embryos, which are cooled to −196 °C in less than two seconds and can be used even after decades in storage.

冷冻器官已被证明极其困难。一旦器官内形成冰晶，它们就报废了。冰晶会造成各种损害，使器官无法使用。但这并没有阻止许多研究人员的尝试。一些人专注于“低温保存”——即通过快速极度冷却，使细胞进入一种玻璃态。这一过程目前已成为卵子、精子和胚胎的常规操作，它们在不到两秒钟内被冷却至 -196°C，即使储存数十年后仍可使用。

No one has managed to cryopreserve and thaw human organs for transplantation. But plenty of human bodies and brains have been stored at ultra-low temperatures in the hope that they might one day be rewarmed and brought back to life. (You can read more about why some people opt for cryonics here.)

目前还没有人能够成功冷冻并解冻用于移植的人体器官。但许多人体和大脑已被储存在超低温环境下，希望有朝一日能被重新加温并复活。（你可以在此处阅读更多关于为什么有些人选择人体冷冻技术的内容。）

In March, I wrote about Stephen L. Coles, a gerontologist who had opted to cryopreserve his own brain. After the scientist died in 2014, his body was taken to Alcor, a cryonics facility in Arizona. A team at the facility removed Coles’s head, perfused his brain with cryoprotective chemicals (which work like antifreeze), removed the brain from the skull, and cooled it to −146 °C. When Coles’s friend Greg Fahy, a cryobiologist, studied pieces of his brain years later, he found that the brain cells, which had shrunk, “bounced back” once they were rewarmed.

今年三月，我写过关于老年学家斯蒂芬·L·科尔斯（Stephen L. Coles）的文章，他选择了冷冻保存自己的大脑。这位科学家于 2014 年去世后，他的遗体被送往亚利桑那州的 Alcor 人体冷冻设施。该设施的一个团队切下了科尔斯的头部，用低温保护化学物质（作用类似于防冻剂）灌注他的大脑，将大脑从颅骨中取出，并将其冷却至 -146°C。多年后，当科尔斯的朋友、低温生物学家格雷格·法希（Greg Fahy）研究他大脑的切片时，发现那些曾经萎缩的脑细胞在重新加温后“恢复了原状”。

But that doesn’t mean the cells are alive, or that it might one day be possible to reanimate the brain. As Matthew Powell Palm of Texas A&M told me at the time: “There are so many ways those neurons could be toast.” Powell Palm is working on other ways to preserve organs. It was he, along with his colleagues, who managed to store supercooled pig kidneys and successfully transplant them, in a study described as “a landmark achievement.” Those organs did better than kidneys stored on ice, he says.

但这并不意味着细胞还活着，也不意味着未来有一天大脑能够复活。正如德州农工大学的马修·鲍威尔·帕尔姆（Matthew Powell Palm）当时告诉我的：“那些神经元可能会以各种方式彻底损坏。”鲍威尔·帕尔姆正在研究其他保存器官的方法。正是他和他的同事成功储存了过冷的猪肾并进行了移植，这项研究被誉为“里程碑式的成就”。他说，这些器官的表现比冰上储存的肾脏要好。

His approach didn’t require cryoprotectants. But other teams are exploring potential chemical cocktails that might allow them to store organs at lower temperatures, potentially for longer periods of time. (More on this in The Checkup soon!)

他的方法不需要低温保护剂。但其他团队正在探索潜在的化学混合物，这可能使他们能够在更低的温度下储存器官，并可能延长储存时间。（更多相关内容请关注即将发布的《The Checkup》！）

Another way to prolong the lifespan of an organ is to use a machine that perfuses it with nutrients, mimicking what happens inside the body. Machine perfusion devices have become more commonly used over the last decade or so and are typically used to maintain livers and kidneys for up to about 24 hours. Researchers are now adapting this protocol for a growing list of organs, even eyeballs—a recent feat that might enable whole-eye transplants.

延长器官寿命的另一种方法是使用机器为其灌注营养物质，模拟人体内的环境。在过去十年左右的时间里，机器灌注设备已变得更加常用，通常用于维持肝脏和肾脏约 24 小时的活性。研究人员目前正在将这一方案应用于越来越多的器官，甚至包括眼球——这是一项最近取得的成就，未来可能实现全眼移植。

In March, I went to visit scientists in Valencia who had developed a perfusion system for uteruses. They had used their device—which they nicknamed “Mother”—to keep a human uterus alive for a day. It’s an exciting time for organ preservation. Keep an eye out for more coverage from MIT Technology Review in the coming weeks.

三月，我拜访了瓦伦西亚的科学家，他们开发了一种用于子宫的灌注系统。他们使用这种被戏称为“母亲”（Mother）的设备，成功让一个人类子宫存活了一天。对于器官保存领域来说，这是一个激动人心的时刻。请在未来几周内持续关注《麻省理工科技评论》的更多报道。