科学家实现糖尿病患者成功移植捐赠皮肤细胞制成的血管

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作者：刘霞 来源：科技日报 发布时间：2011-6-29   5 }' C  e6 y1 Q$ n+ ]
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Illustration shows process of growing blood vessels in a lab.: s- x, U  B8 l

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3 x, U% G2 S' @/ i4 S据美国物理学家组织网6月28日（北京时间）报道，3名波兰透析病人接受了全球首例由捐赠皮肤细胞制造、在实验室中种植而成的血管的移植手术。这项研究的最终目的是制造出一些大小和形状不同的动脉和静脉，供糖尿病患者、肢体受伤的士兵或者需进行心脏搭桥手术的病人等随时取用。
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: ?) v- V5 e  v7 f: t该研究由美国Cytograft组织工程公司进行。研究人员首先从一片捐赠的手背皮肤上提取出细胞，然后将细胞植入组织薄片中，这些组织能被卷成血管。到目前为止，接受者的免疫系统对这些移植血管具有耐受性，因此无需抗排斥的药物或组织配型。
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Cytograft公司的首席执行官陶德·麦克阿里斯特表示，最新制造出来的血管由一个捐赠者提供的细胞制成，技术简单而且成本很低，约为6000美元到1万美元，或许有成千上万名病人会从这项技术中受益。
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未参与该研究的杜克大学心脏病专家罗伯特·哈林顿表示，透析中使用的血管失效是一个“巨大的公共健康问题”，最新研究或将终结这个问题。
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糖尿病患者常会出现肾衰竭的情况，需要通过连接动脉和名为分路的静脉进行透析来将血管中的废物过滤掉。然而，病人一周要进行几次透析，而且容易出现血凝块、感染等并发症。更严重的是，随着病情不断恶化，病人身体上常常找不到合适的分路，而塑料分路的失败率很高，容易引起并发症，医生一直渴望能有自然替代品。这种实验室种植出来的血管没有任何人工物质，也不包含干细胞，因此不会引发争议。
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科学家们此前也进行过类似的实验。2005年，大约10名病人接受了由自己皮肤细胞制成、在实验室中种植出来的血管并取得了成功，但该过程耗时长且非常昂贵，很难投入实际应用中。
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! }  s6 U6 y# I9 j" y4 Z2 ?* T美国心脏协会的前主席蒂莫西·加德纳表示，最新研究使用捐赠细胞，使该技术更实用，应用范围更广。“它提供了一种选择，让我们可以随时获得现成的身体组织，而不需要使用病人自己的细胞来制造。”3 X- C, A  |# ~) |# f

0 g$ A; s, w$ w! M这项研究目前仍处于初期阶段。Cytograft公司正在欧洲和南美进行更大规模的实验，对40名接受实验室种植出来的血管的病人和20名使用塑料静脉的病人进行对比，以验证最新技术的实际效果。
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Diabetics get blood vessels made from donor cells - r3 Q2 {+ o9 z0 W$ t# X
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June 27, 2011 By MARILYNN MARCHIONE ,   4 e2 J8 e) T; U& J4 O
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Three dialysis patients have received the world's first blood vessels grown in a lab from donated skin cells. It's a key step toward creating a supply of ready-to-use arteries and veins that could be used to treat diabetics, soldiers with damaged limbs, people having heart bypass surgery and others.
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The goal is to one day have a refrigerated inventory of these in various sizes and shapes that surgeons could order up as needed like bandages and other medical supplies.# K# ?( o7 v  S, \; }
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The work so far is still early-stage. Three patients in Poland have received the new vessels, which are working well two to eight months later. But doctors are excited because this builds on earlier success in about a dozen patients given blood vessels grown in the lab from their own skin - a process too long and expensive to be practical.9 B2 [6 W* H) [  U" z
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"This version, built from a master donor, is available off the shelf and at a dramatically reduced cost," estimated at $6,000 to $10,000, said Todd McAllister, chief of Cytograft Tissue Engineering Inc., the San Francisco-area company leading the work.. h# {! a) |/ T/ s1 B' X* O
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The American Heart Association considers it so promising that the group featured it on Monday in the first of a new series of webcasts about cutting-edge science.4 v7 B7 G% U' ^! ~1 ~9 v5 w

0 ?" H4 }5 a; a4 ?& p8 I% g  U"This is tremendously exciting," because the failure of blood vessels used in dialysis is "a huge public health problem," said Duke University's Dr. Robert Harrington, a heart expert who had no role in the work.& p( u" c. @' M0 K/ ~5 [

" H% N+ v7 N9 K# DIf a larger study getting under way now in Europe and South America shows success, "this is big news," Harrington said.2 }) S& R0 l5 s$ i0 s
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Kidney failure, which is common in diabetics, requires dialysis to filter wastes from the blood through a connection between an artery and a vein called a shunt. It gets punctured several times a week to hook patients up to the dialysis machine, and complications include blood clots, clogging and infection.
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What's more, patients often run out of suitable sites for these shunts as problems develop. Plastic versions have high rates of failure and complications, too. Doctors have long wished for a natural substitute.
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The lab-grown vessels are free of artificial materials. They don't involve stem cells, so they're not controversial.
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' H2 P$ B% u+ [! LResearchers start with a snip of skin from the back of a hand, remove cells and grow them into sheets of tissue that are rolled up like straws to form blood vessels.
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$ i. F2 `* j7 |. J3 o) o2 v% _; s! CSo far, these lab-grown vessels have been tolerated by the recipients' immune systems; no anti-rejection medicine or tissue matching is needed. That's not surprising because lab-grown skin is already used to treat many burn victims.
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"There are literally hundreds of thousands of patients that could use this technology," McAllister said.3 b" L" D# e+ r8 l- O9 P; F

: b% a* C& C, `! Y& }( N/ _Each year, nearly 400,000 Americans undergo dialysis and half of them use plastic shunts. More than 160,000 people lose limbs because of poor circulation that might be improved with lab-grown vessels.
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About 300,000 people have heart bypass operations using blood vessels taken from other parts of the body to create detours around clogged heart arteries. Some heart patients say the leg wound from removing the long vein to create heart bypasses hurts more than the chest wound for the open-heart surgery.; H8 W, @) J4 z: G; G
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In 2005, Cytograft reported success with its first attempt at dialysis shunts using patients' own skin. Some of the early work was sponsored by the National Heart, Lung and Blood Institute.  @! @: J' s& |- Z0 j8 B! s2 W6 r

" e% j. i5 d, f, tThe new work, using donor cells, makes this advance more practical for wide use, said Dr. Timothy Gardner, a heart surgeon at Christiana Care Health Services in Newark, Del., and former American Heart Association president.5 ~$ X8 ?8 E0 v8 i
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"It provides the option or the opportunity for off-the-shelf graft availability as opposed to something that has to be built from the individual's own cells," he said.0 Q* O# G4 |7 R1 `

) ~  O" k9 k- H* ~Cytograft plans a study in Europe and South America comparing 40 patients getting the lab-grown vessels to 20 getting plastic shunts. Studies also are planned on a mesh version for people with poor leg circulation.
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2 ?- f8 X8 u/ i5 r% b% zMore information: Company and video: http://www.cytograft.com2 R6 a  v4 r" w* I, e0 W, u5 _5 x

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http://www.physorg.com/news/2011 ... sels-grown-lab.html