'Miracle' stem cells help burns victims to see clearly again

Dozens of people whose eyes were severely damaged in chemical accidents have had their sight restored with transplants of their own stem cells.

数十位眼睛在化学事故中严重损伤的患者通过自体干细胞移植而成功恢复了视力。

Researchers say the technique returned normal vision to nearly 100 people. They said one of the patients could see clearly for the first time in more than 60 years.

研究者称该技术让大约一百位患者恢复了正常的视力。他们说其中一名患者在眼瞎60年之后首次重新看见了一个明亮的世界。

'They were incredibly happy. Some said it was a miracle,' study leader Graziella Pellegrini of the University of Modena's Center for Regenerative Medicine said. 'It was not a miracle. It was simply a technique.'

“他们乐疯了。有人说这是一个奇迹。” 研究小组组长、摩德纳大学再生医学中心的Graziella Pellegrini说，“我说呢，这并非奇迹，技术而已。”


Stem cell transplants offer hope to the thousands of people worldwide every year who suffer chemical burns on their corneas from heavy-duty cleansers or other substances at work or at home.

干细胞移植给了全世界每年因为化学烧伤角膜的数千患者治愈的希望，这些患者通常是在工作场所或家中因接触强腐蚀力的清洁剂而不慎灼伤。

In the study researchers took a small number of stem cells from a patient's healthy eye, multiplied them in the lab and placed them into the burned eye, where they were able to grow new corneal tissue to replace what had been damaged.

在本研究中，研究者从患者的健康眼取下少量干细胞，然后在实验室中培养繁殖，最后移植到烧伤的患眼。移植后的干细胞会生长为新的角膜从而替代原来受损的角膜组织。

Since the stem cells are from their own bodies, the patients do not need to take anti-rejection drugs.

因为干细胞来自患者自已的身体，所以移植手术后患者无须摄服抗免疫排斥药物。

Currently, people with eye burns can get an artificial cornea, a procedure that carries such complications as infection and glaucoma, or they can receive a transplant using stem cells from a cadaver, but that requires taking drugs to prevent rejection.

眼睛烧伤后，目前所能得到的治疗是人工角膜移植或尸体角膜移植，但前者导致的诸如感染与青光眼等并发症严重，后者必须服药以预防免疫排斥反应。

The Italian study involved 106 patients treated between 1998 and 2007. Most had extensive damage in one eye, and some had such limited vision that they could only sense light, count fingers or perceive hand motions. Many had been blind for years and had had unsuccessful operations to restore their vision.

这项在意大利完成的研究涉及了106名患者，他们在1998年和2007年接受了干细胞移植。其中大多数患者的一只眼睛有广泛性损伤，其中一些人视力非常有限，只有光感、只能能数手指头或感知手的运动。许多患者多年眼盲、接受过不成功的视力恢复手术。

The cells were taken from the limbus, the rim around the cornea, the clear window that covers the colored part of the eye. In a normal eye, stem cells in the limbus are like factories, churning out new cells to replace dead corneal cells. When an injury kills off the stem cells, scar tissue forms over the cornea, clouding vision and causing blindness.

研究中的干细胞取自异色边缘即角膜缘（角膜是覆盖眼睛有色部分的透明窗口）。正常眼睛中的异色边缘中的干细胞就象工厂，能够生产出新的细胞来替代死亡的角膜细胞。当损伤杀灭了干细胞，瘢痕组织就替代了角膜，遮挡了视线而引起失明。

In the study, published by the New England Journal of Medicine, the doctors removed scar tissue over the cornea and glued the laboratory-grown stem cells over the injured eye.

本研究发表于《新英格兰医学杂志》（NEJM），研究中医生移除了角膜上的瘢痕组织，然后将实验室繁殖出来的干细胞胶合在伤眼上。

Researchers followed the patients for an average of three years and some as long as a decade. More than three-quarters regained sight after the transplant. An additional 13 per cent were considered a partial success. Though their vision improved, they still had some cloudiness in the cornea.

治疗后的研究者对患者进行了随访。随访时间为：其中一些患者平均三年，另一些患者多达十年。 随访发现，超过四分之三的患者在移植后重新获得了视力。另外有13% 的患者被认为部分治愈，即其视力虽然得到改善，但角膜上仍然有一些云翳妨碍视力。

Patients with superficial damage were able to see within one to two months. Those with more extensive injuries took several months longer.

浅表损伤的患者在一两个月内即能视物，而损伤更为广泛的患者则需几个月时间。

The approach would not help people with damage to the optic nerve or macular degeneration, which involves the retina. Nor would it work in people who are completely blind in both eyes, because doctors need at least some healthy tissue that they can transplant.

该方法并不能帮助涉及视网膜的视神经损伤或黄斑部退化患者，对双眼全盲的患者也无效，因为医生说至少需要可供移植的健康细胞。

Adult stem cells, which are found around the body, are different from embryonic stem cells, which come from human embryos and have stirred ethical concerns because removing the cells requires destroying the embryos.

成年人的干细胞虽可在全身发现，但与胚胎干细胞不同，后者来自人类晶胚。晶胚的使用涉及到伦理问题，因为从晶胚移取细胞会彻底毁掉晶胚本身。

Dr Sophie Deng, a cornea expert at the UCLA's Jules Stein Eye Institute, said the biggest advantage was that the Italian doctors were able to expand the number of stem cells in the lab. This technique is less invasive than taking a large tissue sample from the eye and lowers the chance of an eye injury.

加州大学洛杉矶分校Jules Stein眼研究所角膜专家Sophie Deng博士说本研究最大的优势是：意大利的医生们能够在实验室里繁殖干细胞。比起从眼睛提取大组织样本来说，本技术少有侵入性，从而降低了对其中一眼的损伤。

'The key is whether you can find a good stem cell population and expand it,' she said.

“关键在于：你能不能找到好的干细胞群然后加以繁殖。”她说。