很久以前,，生物學(xué)家已知道周邊神經(jīng)(例如手與足的神經(jīng))在受傷后有時(shí)候會重生,，但脊髓及腦內(nèi)的神經(jīng)則不會。目前,，研究人員正尋找方法,，以克服對神經(jīng)生長的自然抑制，幫助脊髓受損者或中風(fēng)患者康復(fù),。
20世紀(jì)九十年代末期,，耶魯大學(xué)神經(jīng)生物學(xué)家斯特里馬特區(qū)分出神經(jīng)細(xì)胞保護(hù)層中的一種蛋白質(zhì)，名為Nogo,，具有抑制人腦及脊髓神經(jīng)重生的能力,。他還識別出神經(jīng)中與Nogo結(jié)合的分子。2001年以來,，他與Biogen公司不斷尋找阻斷這種受體的方法,，以使神經(jīng)可以重生。他們找出幾種有潛力的蛋白質(zhì)藥品,，在脊髓受傷后的一星期內(nèi)注射,，能與Nogo競爭，使之難以和受體結(jié)合,。對早期脊髓受傷的老鼠進(jìn)行的試驗(yàn)表明,，這一方法至少可以局部治好癱瘓。
研發(fā)企業(yè)Biogen估計(jì),，該藥將在2至4年內(nèi)實(shí)施人體試驗(yàn),。
Biologists have long known that peripheral nerves (such as those in the hands and feet) sometimes grow back after they’re injured but that nerves in the spinal cord and brain do not. Now researchers are looking for a way to overcome natural inhibitions to nerve growth and help patients who have suffered spinal-cord trauma or stroke.
In the late 1990s, Yale University neurobiologist Stephen M. Strittmatter isolated a protein in the nerve cells’ protective sheath that inhibits the capacity of brain and spinal-cord nerves to regenerate. Strittmatter also identified the molecule on the nerves to which this regrowth-inhibiting protein, called Nogo, binds. Since 2001, Strittmatter has been working with Biogen to find a way to block this receptor and thus allow the nerves to regrow. They have come up with several potential protein drugs, which could be injected into the spinal cord up to a week after injury and would compete with Nogo to bind to its receptor. "The challenge now is to find the best candidate molecule," says Katherine Turner, Biogen’s vice president of validation biology.
In early tests on mice and rats with spinal-cord injuries, the approach at least partially reversed paralysis. Despite these encouraging results, however, Turner cautions that most researchers don’t consider mice good models for human neurological trauma. Also, it turns out there are two other proteins that bind to the receptor, and it is not yet clear whether the Nogo blockers will displace them as well-a process that may be necessary to trigger regeneration in the human spinal cord.
