主页 > 医学新闻 >
【bio-news】用天然心脏平台制造人工心脏取得成功
By Steve Mitchell
ScienceNOW Daily News
14 January 2008
Donated hearts for lifesaving transplants are scarce, but now researchers may have hit upon a way to generate the blood-pumping organs in the lab--at least in rats. The approach, which involves transplanting cells from a newborn rat onto the framework of an adult heart, produced an organ that could beat and pump fluid. Further refinement will be necessary before the technique is ready for people, but it could also generate other organs.
Approximately 3000 patients in the United States are on the waiting list for a heart transplant, but only about 2000 donor organs become available each year. Stem cells, which can give rise to heart tissue, offer a potential solution. But to form an entire heart, the cells require a framework, or scaffolding, to grow on, and finding an adequate structure has proven difficult. Now, a team led by bioengineer Doris Taylor of the University of Minnesota, Minneapolis, has shown that old hearts stripped of their cells may provide a fix for the scaffolding problem.
Taylor's team started with a heart removed from an adult rat. The researchers soaked it in chemicals to remove the living cells, leaving behind a "skeleton" composed of the heart's nonliving structural tissues, which are made of proteins and other molecules. Onto this scaffolding the researchers placed heart cells from a newborn rat, which are not stem cells but can give rise to multiple types of tissue. The cells took to their new home and after 8 days had assembled into a functioning heart that beat and pumped fluid, the researchers reported online 13 January in Nature Medicine. The new organ had only 2% of the pumping force of an adult heart, but Taylor says that she and her colleagues have since repeated the procedure with about 40 hearts and found that they can produce a stronger organ by adding more cells and giving them more time to grow.
To apply this method to people, the heart scaffolding could come from either human cadavers or pigs, Taylor says. Adult stem cells, such as those found in bone marrow, could be taken from patients awaiting transplants and used to grow the new heart.
Wolfram Zimmermann, a tissue engineer at the University Hospital in Hamburg, Germany, calls the approach exciting but cautions that it's a long way from being ready for use in people. Researchers still have to address several issues, such as identifying an appropriate stem cell that can give rise to heart tissue and working out ways to optimize the growth of the cells so that they ultimately produce a functional heart.
Clyde Yancy, a cardiologist at Baylor University Medical Center in Dallas, Texas, says pig hearts may not be suitable scaffolding because the body could reject them, even with the use of medications to suppress the immune system. Pig heart valves are currently implanted into humans, but Yancy says that an entire heart could prove to be too much for the body to tolerate.
Related sites
Video showing the heart-growing procedure
More about the heart 转自生物谷
Nature Medicine：用天然心脏平台制造人工心脏取得成功
美国科学家近日利用全器官脱细胞化（whole organ decellularization）方法，在实验室中制成了大鼠和猪的人工心脏。这一成果有望为人类人工心脏制备提供新的方法。相关论文1月13日在线发表于《自然—医学》（Nature Medicine）上。
全球患有心力衰竭等严重心脏疾病的人数以万计，每年有大量的患者因得不到合适的捐赠心脏而死亡。目前在实验室中人工制造心脏组织方面已取得一些进展，但要制造三维的能模拟天然心脏复杂结构的人工心脏仍然是个医学难题。
在最新的研究中，美国明尼苏达大学心血管修复中心的Doris Taylor教授和同事采取了脱细胞化的方法，即用天然心脏的平台制造人工心脏。研究人员首先将大鼠和猪心脏中的细胞全部移除，只留下细胞外基质，接着向其中注入新生大鼠心脏“祖细胞”（progenitor cells），然后放在实验室中进行培养。
观测结果令人鼓舞。四天后，观测到收缩；八天后，新心脏开始搏动。Taylor表示，“新心脏的切片研究表明，细胞‘回来’了。”
研究人员相信，脱细胞化过程可被用于制造新的捐赠器官。而且由于新心脏里充满了受者的细胞，所以产生排异反应的几率也会降低。另外，从理论上来说，新心脏应该也可被机体滋养、调控、更新等。
Taylor说：“我们的目标是用患者的干细胞来建造新心脏。而且，此次研究还意味着也许可以人工制造任何器官，肾、肝、肺、胰腺等，凡是你想得到的，我们都有信心造出来。”（科学网 梅进/编译） 自己认领编译，48小时内若未提交，请其他战友自由认领 Building a New Heart From Old Tissue
阅读本文的人还阅读：
作者:admin@医学,生命科学 2011-05-06 17:14
医学,生命科学网