[2013.01.07]科学家发现母亲的脑子里生长着孩子的细胞

[2013.01.07]科学家发现母亲的脑子里生长着孩子的细胞
Scientists Discover Children’s Cells Living in Mothers’ Brains
科学家发现母亲的脑子里生长着孩子的细胞
The connection between mother and child is ever deeper than thought
母亲和孩子的关系比所认为的还要深厚
A living connection 生动的关联
The link between a mother and child is profound, and new research suggests a physical connection even deeper than anyone thought. The profound psychological and physical bonds shared by the mother and her child begin during gestation when the mother is everything for the developing fetus, supplying warmth and sustenance, while her heartbeat provides a soothing constant rhythm.
母亲和孩子之间的关联是很深厚的，新的研究提出了一种身体上的联系，这种联系比任何人所认为的都还要更深厚一些。

母亲和孩子之间心理和身体上的亲密关系从怀孕的时候就开始了，那时母亲对发育中的胎儿来说意味着一切：提供温暖和营养，母亲固定频率的心跳对胎儿来说是一种抚慰。

The physical connection between mother and fetus is provided by the placenta, an organ, built of cells from both the mother and fetus, which serves as a conduit for the of nutrients, gasses, and wastes. Cells may migrate through the placenta between the mother and the fetus, taking up residence in many organs of the body including the lung, thyroid muscle, liver, heart, kidney and skin. These may have a broad range of impacts, from tissue repair and cancer prevention to sparking immune disorders.
母亲和胎儿的身体联系通过一个叫胎盘的器官，由来自母亲和胎儿的细胞组成，作为养料、气体和废物的交换通道。

细胞可以通过胎盘在母亲和胎儿之间移动，可以留在身体的许多器官里面，包括肺、甲状腺肌肉、肝、心、肾以及皮肤。

这些可以产生广泛的影响，从组织修
复、癌症预防到引起免疫紊乱。

It is remarkable that it is so common for cells from one individual to integrate into the tissues of another distinct person. We are accustomed to thinking of ourselves as singular autonomous individuals, and these foreign cells seem to belie that notion, and suggest that most people carry remnants of other individuals. As remarkable as this may be, stunning results from a new study show that cells from other individuals are also found in the brain. In this study, male cells were found in the brains of women and had been living there, in some cases, for several decades. What impact they may have had is now only a guess, but this study revealed that these cells were less common in the brains of women who had Alzheimer’s disease, suggesting they may be related to the health of the brain.
对细胞来说从一个个体进入到另外一个完全不同的个体中并结合在一起是很常见的，这一点太了不起了。

我们习惯认为自己是独一无二的个体，这些外来的细胞好像与这个观点不符，而且表明了大部分人都携带着其他人的遗留痕迹。

这一点或许很值得注意，一项新研究的结果则更让人大吃一惊，研究结果表明来自其他个体的细胞也在脑子里发现了。

在这项研究中，男性的细胞在女性的脑子里面发现了，而且这些细胞在某些情况下可以在那里生存几十年。

这些细胞究竟有何影响目前还仅是猜测，但是这项研究显示那些细胞在患有老年痴呆症的女性脑子里没有那么常见，暗示那些细胞可能和脑部健康有关系。

We all consider our bodies to be our own unique being, so the notion that we may harbor cells from other people in our bodies seems strange. Even stranger is the thought that, although we certainly consider our actions and decisions as originating in the activity of our own individual brains, cells from other individuals are living and functioning in that complex structure. However, the mixing of cells from genetically distinct individuals is not at all uncommon. This condition is called chimerism after the fire-breathing Chimera from Greek mythology, a creature that was part serpent part lion and part goat. Naturally occurring chimeras are far less ominous though, and include such creatures as the slime mold and corals.
我们都认为自己的身体是独一无二的，所以我们的身体里含有来自别人的细胞这一概念好像很奇怪。

更为奇怪的是这样一个想法：尽管我们很确定地认定我们的行为和决定源自我们个人脑子的活动，来自其他个体的细胞却在那个复杂的组织中存在并且发挥着作用。

然而，来自基因截然不同的个体的细胞混合却一点也不罕见。

这种情况被称为奇美拉现象，是以希腊神话中的吐火怪物喀迈拉而命名的，喀迈拉是一只狮头、羊身、蛇尾的怪物。

可是，自然存在的那些喀迈拉们没有那么不吉利，包括一些像粘液菌和珊瑚虫的生物体。

Microchimerism is the persistent presence of a few genetically distinct cells in an organism. This was first noticed in humans many years ago when cells containing the male “Y” chromosome were found circulating in the blood of women after pregnancy. Since these cells are genetically male, they could not have been the women’s own, but most likely came from their babies during gestation.
嵌合现象是指在一个有机体中持续存在着几种不同基因的细胞。

很多年前首先在人体中发现，
当时发现了包含男性“Y”染色体的细胞在怀孕女性的血液中循环流通。

既然这些细胞从遗传学上来说是男性的，它们就不可能是女人们自己的细胞，而极有可能是在怀孕期间从她们的胎儿中来的。

In this new study, scientists observed that microchimeric cells are not only found circulating in the blood, they are also embedded in the brain. They examined the brains of deceased women for the presence of cells containing the male “Y” chromosome. They found such cells in more than 60 percent of the brains and in multiple brain regions. Since Alzheimer’s disease is more common in women who have had multiple pregnancies, they suspected that the number of fetal cells would be greater in women with AD compared to those who had no evidence for neurological disease. The results were precisely the opposite: there were fewer fetal-derived cells in women with Alzheimer’s. The reasons are unclear.
在这项新研究中，科学家们观察到嵌合性细胞不但在血液中流通，而且还嵌入到了脑子里。

他们检查了一些已故女士的脑部，查看是否有包含男性“Y”染色体的细胞存在。

他们发现脑部有60%多的地方有这种细胞，而且分部在不同的脑部分区里。

因为老年痴呆症在多次怀孕的女性身上更为常见，他们怀疑：患老年痴呆症的女性与那些没有神经疾病迹象的女性相比，胎儿细胞的含量要更大一些。

结果却正好相反：患老年痴呆症的女性拥有的源于胎儿的细胞更少。

原因尚不明了。

Microchimerism most commonly results from the exchange of cells across the placenta during pregnancy, however there is also evidence that cells may be transferred from mother to infant through nursing. In addition to exchange between mother and fetus, there may be exchange of cells between twins in utero, and there is also the possibility that cells from an older sibling residing in the mother may find their way back across the placenta to a younger sibling during the latter’s gestation. Women may have microchimeric cells both from their mother as well as from their own pregnancies, and there is even evidence for competition between cells from grandmother and infant within the mother. 嵌合现象最常见的是在怀孕期间细胞通过胎盘交换产生的，然而也有迹象表明细胞可能在喂奶的时候从母亲转移到孩子。

除了母亲和胎儿的交换之外，细胞的交换还可能在子宫里面的双胞胎之间产生，还有可能哥哥或者姐姐留在母亲体内的细胞在母亲后来怀孕期间通过胎盘转到小胎儿身上。

女性的嵌合细胞可能来自她们的母亲也可能来自自己的怀孕，甚至有迹象表明母亲体内存在来自外祖母和婴儿细胞的竞争。

What it is that fetal microchimeric cells do in the m other’s body is unclear, although there are some intriguing possibilities. For example, fetal microchimeric cells are similar to stem cells in that they are able to become a variety of different tissues and may aid in tissue repair. One research group investigating this possibility followed the activity of fetal microchimeric cells in a mother rat after the maternal heart was injured: they discovered that the fetal cells migrated to the maternal heart and differentiated into heart cells helping to repair the damage. In animal studies, microchimeric cells were found in maternal brains where they became nerve cells, suggesting they might be functionally integrated in the
brain. It is possible that the same may true of such cells in the human brain.
胎儿的嵌合细胞到底在母亲体内做些什么还不清楚，虽然有一些可能性很吸引人。

比如，胎儿的嵌合细胞在那些类似的干细胞里能变成很多种不同的组织，可以帮助组织修护。

一个研究小组对这一可能性进行了调查—在一只老鼠妈妈的心脏受伤以后跟踪调查了胎儿嵌合细胞在老鼠妈妈体内的活动：他们发现胎儿细胞移到了母体心脏那里，并且分化成了心脏细胞帮助修复损害。

在动物研究中，在母体脑部发现了嵌合细胞，在那里它们变成了神经细胞，显示它们可能融入到了脑部官能中。

这类细胞在人脑也可能是这样的。

These microchimeric cells may also influence the immune system. A fetal microchimeric cell from a pregnancy is recognized by the mother’s immune system partly as belonging to the mother, since the fetus is genetically half identical to the mother, but partly foreign, due to the father’s genetic contribution. This may “prime” the immune system to be alert for cells that are similar to the self, but with some genetic differences. Cancer cells which arise due to genetic mutations are just such cells, and there are studies which suggest that microchimeric cells may stimulate the immune system to stem the growth of tumors. Many more microchimeric cells are found in the blood of healthy women compared to those with breast cancer, for example, suggesting that microchimeric cells can somehow prevent tumor formation. In other circumstances, the immune system turns against the self, causing significant damage. Microchimerism is more common in patients suffering from Multiple Sclerosis than in their healthy siblings, suggesting chimeric cells may have a detrimental role in this disease, perhaps by setting off an autoimmune attack.
这些嵌合细胞也可能影响免疫系统。

来自怀孕期的胎儿嵌合细胞一部分被母亲的免疫系统认为是属于母亲的，因为从遗传学来说胎儿有一半是和母亲一样的；但是一部分被认为是外来的，源于父亲遗传方面的贡献。

这一点可能“提前给免疫系统打好了预防针”，让它对那些和自身类似但是又有一些遗传差异的细胞保持警惕。

因为基因变异而出现的癌细胞就恰好是这类的细胞，而且有一些研究指出嵌合细胞可能会刺激免疫系统组织瘤子的生长。

例如，与那些患乳腺癌的女性相比，健康女性的血液中发现了更多的嵌合细胞，表明嵌合细胞能以某种方式防止肿瘤的形成。

在其他一些情况下，免疫系统变得和自己做对，因此造成了重大的损害。

患有多发性硬化的病人与他们健康的兄弟姐妹相比，嵌合现象更为常见，表明嵌合细胞可能在这个疾病上起着不良作用，或许是通过引发自体免疫攻击造成的。

This is a burgeoning new field of inquiry with tremendous potential for novel findings as well as for practical applications. But it is also a reminder of our interconnectedness.
这对于新发现以及实际应用来说都是一个崭新的调查领域。

但是它也提醒着我们相互之间的关联。