订制器官

Anthony Atala works in the body shop of the future. He is the director of the Wake Forest Institute for Regenerative Medicine in Winston-Salem, North Carolina, and he and his colleagues use human cells to grow muscles, blood vessels, skin and even a complete urinary bladder. Much of the work is experimental and hasn’t yet been tested in human patients, but Atala has implanted laboratory-grown bladders into more than two dozen children and young adults born with defective bladders that don’t empty properly, a condition that can cause kidney damage. The bladders were the first lab-generated human organs implanted in people. If they continue to perform well in clinical tests, the treatment may become standard not only for birth defects of the bladder but also for bladder cancer and other conditions.

安东尼·阿塔纳在一家未来身体商店上班，是位于北卡罗纳州温斯顿-莎乐姆的苏醒森林再生医学机构的负责人。安东尼和他的同事们用人类细胞生产肌肉、血管、皮肤，甚至是完整的膀胱。工作的大部分是试验性的，并未在人类病人上测试，不过，安东尼已经将实验室里生长出的膀胱移植到超过24个有天生膀胱缺陷的儿童和青年人身上。他们的膀胱不能适当地排空，这会损害肾脏。这些膀胱是第一个被移植到人类身上的实验室制造的器官。如果它们在临床试验上继续表现良好的话，这种疗法将不仅是有天生膀胱缺陷的人，也是患有膀胱癌以及其他症状的人的标准疗法。

Atala and co-workers make replacement parts out of patients’ own raw materials. To produce a bladder, they remove a small piece of a patient’s organ and separate out muscle cells and urothelial cells, which line the urinary tract. They put the cells into lab dishes and bathe each type in a fluid that prompts them to multiply. After six weeks, there are enough living cells for an entire bladder. The researchers then pour the muscle cells onto the outside of a scaffold made of collagen, the protein in connective tissue, and polyglycolic acid, a material used in absorbable sutures. Two days later, they coat the inside of the scaffold with urothelial cells. The new bladder is nurtured in an incubator that mimics body conditions, allowing the cells to grow and knit together. The bladder is then implanted into a patient, where the scaffold gradually dissolves. The researchers have standardized the bladder-growing procedure, Atala says with a smile, and now make “small, medium, large and extra-large sizes.”

安东尼及其合作者们利用病人的自身材料制造替代器官。为制造一个膀胱，他们从病人器官上取出一小片，分离出肌肉细胞以及形成尿道的泌尿细胞。安东尼他们把这些细胞放入实验皿，用可促使他们繁殖的液体清洗。6个星期后，就有了一个完整的膀胱所需的足够的活细胞。然后，研究者们把肌肉细胞大量投放在胶原蛋白支架（结缔组织蛋白）和聚乙醇酸（用于可吸收缝线）的外面。两天后，他们把泌尿细胞涂在支架里面。新膀胱被放在一个模拟身体环境的培养器中培养，这能让细胞生长并相互交织起来。之后，这个膀胱被移植到病人身上，支架会逐渐分解。研究者们已经将膀胱生长程序标准化，安东尼微笑着说，现在“可生产的尺寸有小的、中等的、大的和特大的”。

Regenerative medicine’s once-wild ideas are fast becoming reality. Late last year, Organovo, a biotech company in San Diego, began distributing the first commercially available body-part printer. Yes, you read correctly: a printer for body parts. Using the same idea as an ink-jet printer, it jets laser-guided droplets of cells and scaffold material onto a movable platform. With each pass of the printer head, the platform sinks, and the deposited material gradually builds up a 3-D piece of tissue. Regenerative medicine laboratories around the world have relied on the printer to generate pieces of skin, muscle and blood vessels. Atala’s lab has used the technology to construct a two-chambered mouse-size heart in about 40 minutes.

再生医学机构曾经疯狂的想法正在快速地成为现实。去年晚些时候，圣地亚哥的生物科技公司——新器官公司开始经销第一种可商用的身体部分打印机。对的，你看到的没错：一个印刷身体部分的打印机。就像喷墨打印机一样，它把激光导引的细胞小滴和支架物质喷在一个可移动平台上。随着打印机头的每一次喷出，移动平台下降，积攒下的物质逐渐构成一片三维组织。世界上的再生医学实验室依靠这种打印机生产皮肤、肌肉和血管。安东尼的实验室已经利用这种技术在约40分钟内构建出嘴巴大小的两心室心脏。

Atala and his colleagues have also managed to fashion lab-built kidneys that produce urine when implanted into experimental animals. And within a few years, he says, human skin could be coaxed into growing in a lab and be given to burn victims and other patients who today must undergo painful skin grafts.

安东尼和他的同事们在实验动物移植时，也已经想办法使实验室制造的肾脏产生尿液。他说，在几年时间里，实验室可诱导生长人类皮肤并用于烧伤患者和其他今天还必须经历痛苦皮肤移植的病人身上。

Organs grown outside the body will transform medicine, Atala predicts, but spurring repair and regrowth within the body will be just as important. He and other scientists foresee injecting healthy cells and growth-inducing molecules into diseased or injured lungs, livers and hearts, prompting them to regenerate. Then there’s the ultimate challenge: Could a patient someday regrow an entire limb?

安东尼预测，体外生长的器官将改变医学。不过，加速体内修复和再生长一样的重要。他和其他科学家预测把健康细胞和促生长的分子注射到病变或受伤的肺、肝脏和心脏里，激发其再生长。此时，产生了最终的挑战：某一天病人是否可以再生长出一个完整的肢体来？

“这并非不可能”，安东尼说，“如果蜥蜴做得到，为什么人类不可以？”科学家们正逐渐理解蜥蜴重新长出四肢的精细的基因和生理过程。更多的线索来自实验鼠身上，基因突变使得它们部分地再生长出断掉的脚趾。

Will doctors 40 years from now be able to help humans regrow severed spinal cords, damaged hearts or even lost limbs? Atala says he is optimistic: “The things that are possible today were a dream 20 years ago.”

40年后，医生是否能够帮助人类再生长出受伤的脊柱神经，受创的心脏，或甚至是失去的手臂？安东尼说他对此是乐观的：“今天可能的这些事情曾是20年前的梦想”。

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