美国医生首次利用病人自身细胞培养出人体器官

For the first time,scientists have grown a human organ from patients’ own cells to transplant back into their bodies.

The breakthrough was pioneered by US doctors who developed bladders in the laboratory and are now using their techniques to work on doing the same for 20 kinds of tissues and organs, including blood vessels and hearts.

With tissues grown from their own cells,patients don’t face the risk of rejection as they do with ordinary transplants and wouldn’t have to live with the fear that a donor might not be found.

“This is one small step in our ability to go forward in replacing damaged tissues and organs,” Anthony Atala,who led the research,saidin announcing the development.

Atala developed the procedure for patients born with spina bifida,a birth defect in which their spines were not enclosed and that impaired their bladder functions.

The traditional treatment is to replace the bladder with one formed from part of the intestine,but because the intestine absorbs nutrients and the bladder excretes,the procedure can lead to its own host of problems,including kidney stones,osteoporosis and a higher cancer risk.

So Atala began work in 1990 on an alternative that led to the transplants in seven patients from 4 to 19 years old that he reported in the Lancet medical journal.

Atala,who began his work at Boston Children’s Hospital before moving to the Wake Forest University School of Medicine in North Carolina,reported that he and his team of researchers removed a small portion of the patients’ bladders,extracted cells from the biopsies and began using those cells to grow more like them in Petri dishes. The cells were then placed on a mould shaped like a bladder to grow further.

In seven to eight weeks after the biopsy, the engineered bladders were then sewn onto the patients’ original bladders,and a few weeks after the surgery,the engineered organs had grown into normal-sized bladders and had begun functioning,the researchers said.

The first transplant was done in 1999,and the team said the engineered bladders have functioned as well as bladders reconstructed with intestinal tissue but without the side effects.

The procedure relieved pressure within the bladder,which can cause kidney damage, and improved the patients’ incontinence,they said.

Researchers reported that the rebuilt bladders were up to three times more elastic and better at holding urine.

“We have shown that regenerative-medicine tech-niques can be used to generate functional bladders that are durable,”Atala said. “This suggests that regenerative medicine may one day be a solution to the shortage of donor organs.”

Atala said that further study is needed before the techniques could be put into wide use,but additional clinical trials were scheduled for this year.

科学家已经提取了病人自身细胞，诱导其定向分化，研制出了人体器官，再回植入病人体内，以期修复病人受损的器官，这在医学临床治疗上尚属首次。

美国医生开拓性的研究取得了这项医学上的重大突破。这些美国医生在实验室里诱导细胞分化，成功研制出再生膀胱。他们目前正在研究20种再生组织和器官，其中包括血管和心脏。

与传统的器官移植相比，因为植入的器官是由病人自身细胞分化而来，所以他们将不会面临异体排斥的风险。另外，他们也用不着担心找不到器官捐献者。

这项研究的领衔者安东尼・阿塔拉在宣布这一科研成果时说：“这一成果表明，我们在替换受损伤的组织和器官方面向前迈了一小步。”

阿塔拉为那些患“脊柱裂”的病人做了这种器官移植手术。脊柱裂是一种先天性缺陷，病人脊柱闭合不全，这往往会导致其膀胱功能受损。

对于这种病，传统的疗法是取出病人部分肠子，制成一个新膀胱，来取代原来受损的膀胱，不过，由于肠的功能是吸收养分；而膀胱的功能是排除代谢废物，所以这种疗法会给病人身体健康带来一些后患，包括肾结石、骨质疏松以及高的患癌症风险。所以，从1990年起，阿塔拉就开始寻找新的替代疗法。

如今，他已经成功地给7名4~19岁的病人实施了这种器官移植手术。这些成果他已经发表在《柳叶刀》医学杂志上。

早在去卡罗来纳州北部的威克森林大学医学院工作之前，阿塔拉就在其工作的波士顿儿童医院展开了这项研究工作。阿塔拉报道说，他和其他科研人员在患者身上提取了一小部分膀胱组织，从中提取活细胞放在皮氏培养皿中培养，细胞分裂增殖产生了更多的类似细胞。然后再把这些细胞置入一膀胱形的模子中使其进一步分化。

研究人员说，此后的7到8周，通过手术把再生的膀胱与患者原来受损的膀胱缝合在一起。几个星期后，再生膀胱长至正常形态并开始发挥正常生理功能。

这种器官移植的最早一例是在1999年完成，研究小组报告说，这种再生膀胱有着与由肠组织重建的膀胱相同的良好生理功能，而且还没有副作用。

他们认为，手术降低了膀胱内侧所受的压力，这种压力可以造成肾脏功能受损，而且还会使病人尿失禁病情加重。

研究人员报告称，与传统的人工膀胱相比，这种再生膀胱的弹性是前者的3倍，并且有较好的蓄尿能力。

阿塔拉说：“我们已经证明了再生医疗技术可以用来研制能长久发挥正常生理功能的膀胱，这表明，有朝一日，再生医疗技术可以解决捐赠器官来源匮乏难题。”

阿塔拉说，在这项新技术广泛应用之前，还需要进一步研究，今年我们将开展更多的临床实验。