肠道中存在着“第二大脑”

帕金森氏症的发现暗示了肠道中存在着“第二大脑”

A growing body of evidence is forging a stronger and stronger connection between the onset of Parkinson’s disease and the gut. Scientists at Karolinska Institutet in Sweden and the University of North Carolina at Chapel Hill have thrown further weight behind this theory, with an investigation of cellular behavior in the nervous system of the digestive system revealing possible tell-tale signs at the earliest stages of the disease.

越来越多的证据表明，帕金森病的发病与肠道之间的联系越来越紧密。瑞典卡罗琳斯卡研究所和北卡罗来纳大学教堂山分校的科学家们进一步强调了这一理论，他们对消化系统神经系统的细胞行为进行了研究，揭示了疾病早期可能的信号。

The notion that Parkinson’s disease could get its start in the gut has been around for some time, but in recent years we are seeing some compelling research that suggests our bellies may well play an important role in its onset. The disease is characterized by the cell death of neurons that secrete dopamine in the brain, which drives the motor impairments and other common symptoms of the illness.

关于帕金森氏病可以在肠道中开始的观念已经存在了一段时间，但是近年来，我们看到一些引人注目的研究表明，我们的腹部很可能在其发病中起重要作用。该疾病的特征是大脑中分泌多巴胺的神经元细胞死亡，这会导致运动障碍和该疾病的其他常见症状。

What causes the demise of these neurons is not known for certain, but a leading hypothesis is that it is caused by aggregations of misfolded proteins known as Lewy bodies. An animal study last year produced the best evidence to date that these toxic protein clumps first form in the gut and move upward to the brain via the vagus nerve.

导致这些神经元死亡的原因尚不确定，但一个主要的假设是，它是由错误折叠的蛋白质(称为路易小体)的聚集引起的。去年的一项动物研究提供了迄今为止最好的证据，表明这些有毒蛋白团块首先在肠道中形成，然后通过迷走神经向上移动到大脑。

This new research hints at the role the enteric nervous system, as the regulator of digestive system, could play in these processes. Made up of a hundreds of millions of neurons, the body’s largest collection outside the brain, the enteric nervous system can operate independently of the central nervous system and for this reason is sometimes referred to as “the second brain.”

这项新的研究表明，肠神经系统作为消化系统的调节者，可能在这些过程中发挥作用。肠道神经系统由数亿个神经元组成，是人体大脑以外最大的集合，它可以独立于中枢神经系统运作，因此有时被称为“ 第二大脑”。

The authors of the new research studied gene expression in mice in combination with human genetics to systematically identify cell types that underly certain brain disorders. They then analyzed brain tissue taken from both healthy subjects and sufferers of Parkinson’s, taken at different stages of the disease. This revealed alterations in enteric neurons, “even at the earliest stages of disease progression,” the scientists write.

这项新研究的作者结合人类遗传学研究了小鼠中的基因表达，以系统地识别某些脑部疾病的细胞类型。然后，他们分析了从健康受试者和帕金森氏症患者的脑组织中提取的，在疾病的不同阶段采集的组织。科学家写道，这揭示了肠道神经元的改变，甚至在疾病发展的最早阶段。

"As expected, we found that dopaminergic neurons were associated with Parkinson's disease,” says senior author Patrick Sullivan. “More surprisingly, we found that enteric neurons also seem to play an important role in the disorder, supporting the hypothesis that Parkinson's disease starts in the gut.”

“正如预期的那样，我们发现多巴胺能神经元与帕金森氏症有关，”资深作者帕特里克·沙利文说。“更令人惊讶的是，我们发现肠内神经元似乎在这种疾病中也起着重要作用，支持帕金森氏病始于肠道的假设。”

The team’s research also produced another useful insight. By looking at these brain tissue samples taken at different points in disease progression, they found that important support cells in the brain called oligodendrocytes were impacted early on, even before the loss of the dopamine-producing neurons.

该小组的研究也产生了另一个有用的见解。通过观察这些在疾病进展的不同阶段采集的脑组织样本，他们发现大脑中重要的支持细胞少突胶质细胞在早期受到影响，甚至在产生多巴胺的神经元丧失之前。

“These results suggest that oligodendrocyte could be an attractive target for therapeutic interventions as they appear to be affected before dopaminergic neurons,” says the Karolinska Institutet’s Julien Bryois, senior author of the study.

该研究的高级作者卡罗林斯卡研究所的朱利安·布赖伊斯(Julien Bryois)说：“这些结果表明，少突胶质细胞可能是治疗干预的一个有吸引力的靶标，因为它们似乎在多巴胺能神经元之前就受到了影响。”

The research was published in the journal Nature Genetics.

这项研究发表在《自然遗传学》杂志上。