Regrowth of Heart Muscle May Be Possible
From VOA Learning English, this is the Health & Lifestyle report.
It may seem like a moment in a science fiction movie. In a fierce battle, a creature loses an arm but, then, grows another one to take its place.
However, this is not science fiction. It is scientific fact. Some fish and amphibians, such as salamanders, can regrow lost limbs and organs.
As mammals evolved they lost the ability to regrow, or regenerate, parts of their body. However, experiments show that it may be possible to regain that ability.
Tropical freshwater zebrafish are popular pets. They are also popular as lab animals. Their embryos are clear, or translucent. They can regrow damaged fins, skin and hearts. Zebrafish are also genetically similar to humans.
In 2013, the website Sci-News reported that researchers had found that 70 per cent of "protein-coding human genes" are related to genes found in the zebrafish. The report also said that researchers at the Wellcome Trust Sanger Institute in Britain also found that 84 per cent of genes known to be connected to human disease have a zebrafish counterpart.
These researchers published their findings in the scientific journal Nature. Sanger is a non-profit British genomics and genetics research institute.
So, it is no surprise that scientists at the University of Pittsburgh in Pennsylvania are using tiny zebrafish to regenerate severely damaged mouse hearts.
Scientist Wang Yadong is one of the Pittsburg researchers. He and his team are studying the ability of zebrafish to regenerate limbs and organs. Wang says you can cut away about 20 per cent of the zebrafish heart and it will regenerate. He add that same process may be able to help humans.
"So that amazing ability make(s) us think it's possible to borrow some of that repair regeneration mechanism and use that to help us to regenerate our heart."
Scientists injected an "extracellular matrix," or ECM, from the heart of a zebrafish into a severely damaged mouse heart.
In biology, an extracellular matrix is a substance produced and released by cells that gives structural and biochemical support to surrounding cells. Think of ECM as cellular stuff that gives room and board to surrounding cells.
So, what did the researchers find?
They found that the heart muscle regenerated in days. They found something else. The healing was even faster when the ECM was taken from zebrafish that was itself in the process of re-growing damaged tissue.
Wang adds that if you had to choose between the two matrices, the "healing matrix" is more powerful of the two.
"Between the two, the healing matrix from the zebrafish heart is even more potent than the normal one."
A molecule called neuregulin 1 seems to play a major role in causing the regeneration to happen.
"We did see the zebrafish heart has more neuregulin 1 than the mouse heart. The healing zebrafish heart has even more than the normal. So, it does indicate that neuregulin probably plays a role but we have to do more study on that."
The next step will be to test the regenerative abilities of zebrafish ECM on larger mammals.
I'm Anna Matteo.
1.heart muscle 心脏肌肉
Destruction of heart tissue resulting from obstruction of the blood supply to the heart muscle.
2.fiction movie 科幻片
Gene and Beth are watching a science fiction movie about aliens.
3.lab animals 实验动物
So far, the research has focused on humans with Alzheimer's and lab animals.
4.cut away 切掉
We cut away the dead branches from the trees.
1.A molecule called neuregulin 1 seems to play a major role in causing the regeneration to happen.
play a major role in 扮演重要角色
Accountants play a major role in this measurement process by qualifying data.
The UN would play a major role in monitoring a ceasefire.
2.The report also said that researchers at the Wellcome Trust Sanger Institute in Britain also found that 84 per cent of genes known to be connected to human disease have a zebrafish counterpart.
connected to 金融犯罪
These appliances should not be connected to power supplies.
The dispute is not directly connected to the negotiations.
这样的场景或许只在科幻电影中出现 。某生物经过一场激烈的战斗后失去一只手臂，之后又长出来一条新手臂 。
不过，这不再是科幻小说中的场景，这已经成为科学事实 。某些鱼类和蝾螈类两栖动物可重新长出新的肢体和器官 。
哺乳动物因进化失去了身体部位的再生能力 。然而，实验表明它们可能重新恢复这种能力 。
作为宠物，热带淡水斑马鱼十分受欢迎 。它们在实验领域也备受青睐 。它们的胚胎为透明或半透明状态，它们可以使受损的鳍、皮肤和心脏再生 。另外，斑马鱼的基因与人类相似 。
2013年，《科技新闻》网站报道称，研究人员发现，人类70%的蛋白编码基因与斑马鱼的基因相关 。该报道还指出，英国韦尔科姆基金会桑格研究所的研究人员发现，人类疾病相关基因中有84%可以在斑马鱼中找到对应基因 。 。
研究人员将研究结果刊登在《自然》杂志上 。桑格研究所是英国一家非营利性的基因学和遗传学研究所 。
王亚东是匹兹堡大学的研究人员之一 。他与团队正在研究斑马鱼再生肢体和器官的能力 。王亚东表示，斑马鱼约20%心脏被切掉后会再生 。他补充说，这种修复过程或许能帮助人类 。
在生物学中，细胞外基质是细胞产生和释放的一种物质，能够向周围细胞提供结构和生化支持 。人们把细胞外基质视为可以给周围细胞提供“食宿”的细胞原料 。
他们发现老鼠心脏肌肉在几天内能够再生 。他们还发现，自身处于受损组织再生过程的斑马鱼的细胞外基质的愈合作用更明显 。
王亚东表示，“在斑马鱼心脏中确实发现了比老鼠心脏更多的“神经调节蛋白1” 。而愈合中的斑马鱼心脏比正常情况含有更多“神经调节蛋白1” 。显而易见，这种神经调节蛋白可能发挥了作用，但是我们还需要进行更多相关研究 。”