干细胞有望治疗胎儿成骨不全

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将干细胞注射到发育中的胎儿听起来好像有点危险，但是却能够延长患有脆骨病儿童的生命。

  来自伦敦皇家学院的Nicholas Fisk和同事对人类III型脆骨病（brittle bone disease）或成骨不全症小鼠模型进行了研究。这种能够能通过DNA检测或超声波进行诊断的遗传缺陷会破坏胶原质的产生，从而导致骨骼脆弱和生长迟缓。

   Fisk的研究组将人类胚胎间充质干细胞通过子宫壁注射到14天大的小鼠胚胎中。在三个月大时，与未处理小鼠相比，处理小鼠的长骨骨折只有对照的三分之一。而且，它们的骨骼还更强壮、腿骨更长。

  尽管目前已经有药物能够治疗这种疾病，但是干细胞移植则可能具有更多的益处，例如肢体骨骼长度的增加。事实上，这种治疗方法在美国也有尝试。Fisk在上周的国际干细胞研究协会年会上公布了这些结果。

  “成骨不全”又称脆骨病，是一种遗传性疾病，属于先天性结缔组织缺陷，以前分为先天型和迟发型两种类型，现分为I、II、III、IV四种类型。脆骨病主要是因胶原蛋白（collagen）量不足与质的缺陷导致的。在骨胳系统导致骨溶解吸收过速，造成骨质疏松而易骨折，骨胳强度耐受力变差而容易脆弱骨折的疾病。  

  这种疾病因胶原蛋白基因突变的不同，而则造成不同的临床症状。由轻微的骨质疏松表现至骨折频繁，甚至在子宫内胎儿阶段即产生骨折，最严重的造成在婴儿出生不久后就夭折，甚至造成死产。

原始出处:

Stem cells toughen up fetus's brittle bones
04 June 2007
NewScientist.com news service
Injecting stem cells into a developing fetus might sound risky, but it could prolong the lives of children with brittle bone disease.

Nicholas Fisk and colleagues at Imperial College London studied mouse models of human type III brittle bone disease, or osteogenesis imperfecta (OI). The genetic defect - detected in human fetuses by DNA testing or ultrasound - disrupts collagen production, leading to weak bones and stunted growth. Those with type III OI suffer fractures while in the womb and rarely survive beyond early adulthood.

Fisk's team injected human fetal mesenchymal stem cells through the wall of the uterus into 14-day mouse fetuses. At the age of 3 months, treated mice had suffered just one-third of the long-bone fractures compared with untreated mice. Their bones were also stronger and their leg bones longer.

While drugs exist to treat the disease, stem cell transplants seem to have extra benefits, such as this boost in limb length, says Fisk. In fact, the treatment has already been tried in the US on three children with OI whilst still in the womb, with promising early results seen after the babies were born. Fisk, who last week presented the work at the annual meeting of the International Society for Stem Cell Research in Cairns, Australia, believes the treatment should now be offered on a case-by-case basis. Other experts caution, however, that a full clinical trial in people is needed first.

From issue 2610 of New Scientist magazine, 04 June 2007, page 20