In the future, we may not need to rely on human donations for life-saving skin grafts.

That’s the goal of XenoTherapeutics, a Boston-based biotech nonprofit. Recently, the U.S. Food and Drug Administration approved the group’s initial application for temporary skin grafts curated from genetically modified pigs. This means that they can start testing pig skin grafts on people who have experienced severe burns. It’s the first time that an animal organ has been cleared for human testing in the United States.

Skin, the body’s largest organ, plays a crucial role in the immune system by blocking pathogens from reaching our vulnerable internal organs. It also holds in water, electrolytes and other nutrients, and helps the body maintain a constant temperature. People with severe skin damage are at a high risk of developing deadly infections or organ failure as a result of changes in temperature or hydration.

Skin grafts can help protect these patients as they heal. At the moment, the only skin grafts available in the U.S. come from cadavers who have agreed to be organ donors, or patients who have undergone surgery to remove excess skin after dramatic weight loss. These human skin used for grafts are a “rare commodity.”

XenoTherapeutics, which gets its name from xenotransplantation, or animal-to-human transplants, has bred pigs that have skin remarkably similar to our own. Although pig skin normally produces a type of sugar human skin does not, these pigs have been genetically modified not to make it. Grafts from these pigs are therefore more likely to slide under the radar of the host’s immune system — at least temporarily. The idea is that they could be used for immediate burn treatment, followed by human skin graft treatment later.

“I would venture that if we did a Coke and Pepsi side-by-side comparison... you’d be hard-pressed to tell which was the human cadaveric allograft versus (the pig graft),” said XenoTherapeutics CEO Paul Holzer.

The nonprofit has been working closely with physicians at Massachusetts General Hospital, who will help conduct the clinical trials starting next month.

Words to Learn 相关词汇

【电解质】diànjiězhì electrolyte a substance that dissociates into ions when fused or in solution, thus becoming capable of conducting electricity

【不引起注意】bù yǐnqǐ zhùyì under the radar not getting attention, unnoticed

未来，可挽救生命的皮肤移植或许无需再依赖人类自身捐献了。

这就是总部设在波士顿的非营利性生物科技企业塞诺移植治疗公司的目标。

最近，美国食品和药物管理局批准了该公司使用基因改良猪的皮作为临时移植皮肤的初步申请。这意味着，他们可以开始对严重烧伤者进行猪皮移植测试。这也是美国首次批准用动物器官进行人体测试。

皮肤是人体最大的器官，可阻止病原体侵入人体脆弱的体内器官，因此在免疫系统中发挥着至关重要的作用。此外，皮肤可锁住水分、电解质及其他营养物质，还可帮助人体保持体温稳定。皮肤严重受损者因体温或水合状态的改变而患致命性感染或器官衰竭的风险很高。

移植皮肤可在患者痊愈过程中对患者加以保护。当前，在美国获取移植皮肤的唯一途径是使用同意捐献器官者死后留下的皮肤，或因体重严重下降做多余皮肤去除术的患者皮肤。用于移植的人类皮肤可谓是“稀缺商品”。

塞诺移植治疗公司的英文名就源自异种器官移植概念 —— 即把动物器官移植给人体。该公司饲养的猪，其猪皮与我们人类的皮肤极为相似。猪皮一般会生成一种糖而人皮则不会，为了使这些猪不生成这种糖，该公司对猪实施了基因改良。这样一来，这些猪皮通过接受移植者免疫系统监测的可能性就更高了 —— 至少短期内可以通过。这些猪皮可被用于紧急烧伤处理，之后再进行人皮移植。塞诺移植治疗公司首席执行官保罗·霍尔泽说：“我敢说，这就像你把可口可乐和百事可乐放在一起进行对比，你很难分得清哪个是源自人类尸体的同种异体移植皮肤，哪个是移植猪皮。”

这家非营利性企业一直在与马萨诸塞综合医院的医生们进行紧密合作，这所医院将从下月起协助进行临床实验。

(Chinadaily.com.cn)