Scientists have dreamed for centuries about using animal organs to treat ailing humans. In recent years, those efforts have begun to bear fruit: Researchers have begun transplanting the hearts and kidneys of genetically modified pigs into patients, with varying degrees of success.

几个世纪以来，科学家们一直梦想着利用动物器官治疗患病的人类。近年来，这些努力开始取得成果：研究人员已着手将经过基因改造的猪的心脏和肾脏移植到患者体内，取得了不同程度的成功。

But lungs are notoriously difficult to transplant, even from human to human, and mortality rates are high. Now, in the first procedure of its kind, Chinese scientists on Monday reported transplanting a lung from a pig into a brain-dead man.

然而，肺脏移植向来难度极大——即便在人类之间进行，死亡率也很高。如今，中国科学家于周一报告完成了全球首例猪肺移植到脑死亡者体内的手术，在该领域尚属首次。

The organ sustained damage after it was transplanted but functioned to some degree, scientists at Guangzhou Medical University reported in the journal Nature Medicine. The organ was removed after nine days.

广州医科大学的科学家在《自然·医学》杂志上发表报告称，移植后的猪肺虽出现损伤，但仍在一定程度上具备功能，术后九天该器官被移除。

American scientists called the procedure exciting but urged caution.

美国科学家称这一手术令人振奋，但也强调需保持谨慎态度。

“It’s very promising and a great first step, but there is a lot more work to do to make this feasible,” said Dr. Stephanie Chang, an associate professor in cardiothoracic surgery at N.Y.U. Grossman School of Medicine and surgical director for the lung transplant program.

“这一成果极具前景，是重要的第一步，但要实现临床可行性，仍有大量工作要做，”纽约大学格罗斯曼医学院心胸外科副教授、肺移植项目外科主任斯蒂芬妮·张（音）博士表示。

“If there is a way to actually source organs from animals and have them work in genetically modified ways, that would be very exciting,” she said.

“若真能找到从动物身上获取器官并通过基因改造使其适配人体的方法，那将是非常令人兴奋的突破。”她还说。

While dialysis can help people with kidney failure, “there’s not much that can replace your lungs,” Dr. Chang added.

张博士还指出，透析可以帮助肾衰竭患者维持生命，但“目前几乎没有方法能真正替代肺的功能”。

In the United States alone, millions suffer from severe, life-threatening lung disease, including chronic conditions caused by Covid. Yet there is an extreme shortage of human lungs available for transplant. Many donor organs, damaged by a lifetime of environmental exposure, are simply not in good enough condition to transplant.

仅在美国就有数以百万计的人患有严重的、危及生命的肺部疾病，其中包括由新冠病毒引发的慢性肺病。然而，可供移植的人类肺源极度短缺。许多捐赠者的肺脏因长期受环境影响受损，状态根本无法满足移植要求。

The Chinese scientists transplanted the left lung of a pig that had undergone six gene edits into a brain-dead 39-year-old man. Because the procedure left his functioning right lung in place, the experiment did not prove that the transplanted lung could sustain life on its own, critics noted.

中国科学家将一只经过六处基因编辑的猪的左肺移植到一名39岁的脑死亡男性体内。批评人士指出，由于手术保留了患者原本功能正常的右肺，此次实验并未证明移植的猪肺能够独立维持生命。

“It’s impressive, but it doesn’t answer the question: Is that lung working?” said Dr. Richard N. Pierson, a professor of surgery at Harvard Medical School and the Massachusetts General Research Institute, who has done extensive research on pig heart transplants.

“成果令人印象深刻，但它没有回答核心问题：这颗肺脏真的在正常工作吗？”哈佛大学医学院及麻省总医院研究所外科学教授、长期从事猪心脏移植研究的理查德·皮尔森博士表示。

The research team could have blocked off blood flow to the right lung in order to assess how well the transplant was working, he said, but they did not. “They’ve shown a pig lung can be sewn into a human being and shown what happens,” he said. “But an opportunity was missed in this experiment.”

他认为，研究团队本可以通过阻断右肺的血液供应来评估移植肺的功能，但他们并未这样做。“他们证明了猪肺可以缝合到人体内，并观察了后续情况，但这次实验错失了关键的验证机会，”他说。

The Chinese authors of the report did not respond to email queries for more information.

该报告的中国作者未回复记者寻求更多信息的电子邮件。

The pig’s lung also suffered damage within 24 hours of the transplant. Signs of antibody-mediated rejection, which occurs when the body forms antibodies and attacks the organ and is the most common cause of transplant failure, were observed at three and six days after transplantation. Fluid buildup was also discovered in the lung.

此外，移植后的猪肺在24小时内就出现了损伤。术后第三天和第六天，研究人员观察到了抗体介导排斥反应的迹象——这种反应由人体产生抗体攻击移植器官引发，是移植失败最常见的原因。同时，猪肺内还发现了积液。

Since lungs come into contact with the environment with every breath and are constantly being exposed to external threats, like allergens, pollutants and viruses, they are rich in immune cells.

由于肺脏每一次呼吸都会与外界接触，并持续暴露于过敏原、污染物、病毒等外部威胁中，其免疫细胞含量极高。

The immune responses in these organs are thus more aggressive than those seen in other solid organs, like the kidney, and transplanted lungs are more likely to fail.

因此，肺脏的免疫反应比肾脏等其他实体器官更为强烈，移植后的肺脏也更容易衰竭。

“If you put all the organs on a spectrum, the lung will always be the hardest to do,” said Dr. Leonardo Riella of Massachusetts General Hospital, who performed the first successful transplant of a kidney from a gene-edited pig into a living human.

“若将所有器官按移植难度排序，肺脏永远是最难的，”麻省总医院的莱昂纳多·里埃拉博士说，他曾完成全球首例基因编辑猪肾移植到活人的成功手术。

In human-to-human transplants, “a normal kidney may last 12 to 14 years, while a lung may last five to seven years,” he said.

他表示，在人类之间的器官移植中，“一颗健康的肾脏通常能存活12至14年，而肺脏的存活时间仅为五至七年。”

Research teams around the world have been increasing the number of experiments with organs from genetically modified pigs bred by different companies, with various sets of gene edits.

目前，全球各地的研究团队正不断增加对基因改造猪器官的实验探索，这些猪由不同公司培育，进行不同组合的基因编辑。

In March, a team of Chinese scientists reported that they had transplanted a genetically altered pig’s liver into a brain-dead person, where it functioned for 10 days, producing bile and porcine albumin and maintaining stable blood flow without signs of rejection.

今年3月，一组中国科学家报告称，他们已将一颗基因改造猪的肝脏移植到一名脑死亡者体内，该肝脏正常运转了10天，期间能产生胆汁和猪白蛋白，维持稳定血流，且未出现排斥反应。

The U.S. company eGenesis is also studying the transplantation of pig livers in addition to other organs. In April, the company received authorization from the Food and Drug Administration to start clinical trials using pig livers to treat patients with a condition called acute-on-chronic liver failure. The treatment involves circulating the patients’ blood outside the body through the animal’s liver.

美国公司eGenesis也在研究猪肝移植及其他器官移植。今年4月，该公司获得美国食品药品监督管理局(FDA)授权，启动一项临床试验：利用猪肝脏治疗慢加急性肝衰竭患者，具体方式涉及将患者血液引出体外，通过猪肝脏进行过滤。

Much of the focus of such clinical research has been on kidneys, since over half a million Americans suffer from kidney failure and require dialysis, including about 100,000 who are on waiting lists for human kidneys. There is an acute shortage of donated organs, with fewer than 25,000 transplants completed in 2023. Many patients die while they wait.

此类临床研究的重点多集中在肾脏领域：美国有超过50万人患有肾衰竭并需要透析治疗，其中约10万人在等待人类肾脏移植的名单上。捐赠器官的短缺问题极为严峻——2023年完成的肾脏移植手术不足2.5万例，许多患者在等待中离世。

In February, the F.D.A. also gave the go-ahead to United Therapeutics Corporation to start a clinical trial transplanting kidneys from genetically engineered pigs into patients with kidney failure.

今年2月，FDA还批准联合治疗公司启动一项临床试验，将经过基因编辑的猪的肾脏移植给肾衰竭患者。

One New Hampshire man who received a kidney from a genetically altered pig produced by eGenesis has been living with the organ since January. He is the longest survivor with a pig’s kidney to date.

今年1月，美国新罕布什尔州一名男子接受了eGenesis的基因改造猪的肾脏，截至目前仍依靠该器官正常生活，他也是迄今为止猪肾移植术后存活时间最长的患者。