科学家在脊髓受损修复方面取得重大突破

meteor

2014年12月5日讯 /生物谷BIOON/ --众所周知，脊柱是人体及其重要的一部分，一旦受到损伤，轻则运动能力受损，重则危及生命。

每年，由于交通事故等意外而造成脊柱受损的患者数以万计，许多人余生甚至只能在轮椅上度过。其中最为著名的例子当属当年超人的扮演者克里斯多夫，这不能不说是一种极大的痛苦。

然而，与之对应的是，目前医学界并没有一种成熟的方法能够有效的修复这种损伤，减轻这类患者的痛苦，仅有的一些恢复疗法也是通过采用干细胞疗法来治疗患者，然而这种介入治疗的方法很容易再次损伤患者的身体，从而引起更严重的后果。

最近，美国凯斯西储大学和美国国家健康中心的研究人员合作，小鼠动物模型上成功的修复了脊髓内受损的神经元，为打破这一僵局带来了一丝希望。研究人员介绍称，一般而言，脊柱受损会导致其中的神经元轴突遭到破坏，而轴突则是大脑下达指令到达躯干部的必经之路。轴突受损直接导致信号通路的破坏，进而使患者部分机体无法控制，从而出现麻痹甚至瘫痪的症状。另一方面，由于脊柱瘢痕组织中会表达一种名为PTP sigma的酶及相关蛋白，这些蛋白会阻碍神经元轴突的修复，这也促使受损神经元无法进行自我修复。

因此凯斯西储大学的研究人员设计了一种能够特异性阻断PTP sigma的药物。当科学家将这种药物通过皮下注射的方式注入到脊柱受损的大鼠模型后，他们观测到在大鼠脊髓受损部位以下的神经元开始恢复！这一现象预示着科学家将有可能根据这一原理开发出一种修复脊髓损伤的药物以治疗无数瘫痪在床的患者。（生物谷Bioon.com）

详细英文报道：

Researchers at Case Western Reserve UniversitySchool of Medicine have taken an end-around approach to treating spinal cord injuries, crafting a treatment that has shown the promise of reversing paralysis in early studies.

As the scientists explain, damage to the spine often severs long nerve fibers called axons, interrupting brain signals and leading to paralysis. During the healing process, axons try to traverse the damaged area and reconnect with their counterparts but, due to the interaction between an enzyme called PTP sigma and class of proteins expressed in scar tissue, they can't get across.

Examining that impasse, Case Western's Bradley Lang came up with the idea of creating a drug that could block PTP sigma and help fledging axons grow and restore the body's nerve network. And, in a preclinical study published in Nature, the treatment did just that.

With help from the National Institutes of Health, a Case Western team led by professor Jerry Silver tried the subcutaneous drug on rats with paralysis due to injury, finding that the treatment led to marked improvements in their ability to walk and urinate. Examining the rats in the treatment group, Silver's team noted that their drug spurred rampant axon growth below the site of injury, lending weight to the guiding hypothesis and lighting the way for future study.

It's extremely early days for Case Western's treatment, of course, and recent scientific history is littered with agents that show exhilarating promise in animals only to fail quietly on further examination. That said, there are no available drugs to help spinal cord injuries heal, and many in-development treatments are stem cell therapies, requiring invasive procedures that could further damage tissues on the mend. Case Western's candidate, by contrast, can be injected underneath the skin.

"We're very excited at the possibility that millions of people could, one day, regain movements lost during spinal cord injuries," Silver said in a statement. "... We now have an agent that may work alone or in combination with other treatments to improve the lives of many."

详情可以查看：Nature doi:10.1038/nature13974