全球第一枚以患者幹細胞在實驗室中培育的人工心臟，可望在一周內生成。美國明尼蘇達大學再生醫學專家上周六宣布好消息，他們將需要移植心臟患者的幹細胞，注入處理過的人類心臟支架，若順利，這枚人工心臟將在未來一周出現心跳。此研究為日後培養個人替代臟器奠定重要基礎。

明尼蘇達大學這批科學家由朵瑞絲泰勒博士（Dr. Doris Taylor）領軍，他們從捐贈者遺體取出心臟，在實驗室以界面活性劑洗去心臟細胞，取得有「鬼心」（ghost heart）之稱的膠原蛋白支架。再將取自需換心者的數百萬顆年輕幹細胞注入支架，假以時日，這群幹細胞會附著上支架、分裂至特定數量，心臟即能自主搏動。    

突破捐贈不足瓶頸

 

泰勒上周六在於紐奧良市舉行的「美國心臟病學學會」年會，宣布研究進程，她說：「這批人工心臟還在發育，我們希望未來一周內就能看到它們出現搏動跡象。」泰勒指出，其研究能突破移植手術兩大瓶頸，一是器官捐贈數不足，另一是複雜的排斥現象。以換心者自體幹細胞培養出的新心臟，植入人體後產生排斥的機率可望下降。

照再生醫學界現有研究速度，泰勒認為，製造全器官移植用人工心臟的技術，終有一天會發展純熟。她的團隊就利用過鼠心及豬心洗出支架，再注入人類幹細胞，幹細胞最後都順利快速分裂，使人工心臟獨立跳動，搏動力量甚至達正常心臟的25%，但光是人工心臟獨立跳動已是團隊的一大勝利。

研究基地在美國的泰勒進行這項最新研究時，為獲得足夠捐贈心臟，遠赴豬心來源豐富的西班牙。泰勒說：「我們離培育出移植用的心臟還很遠，但我們已為人類器官移植開了一扇窗。」

未來可培養肺肝腎

 

若技術成熟，人類能用自己的幹細胞培養個人替代臟器，肺、肝、腎都不成問題。幹細胞除能從嬰兒出生時的臍帶血取得造血幹細胞外，也可從成人組織，如骨髓取得的間葉幹細胞，脂肪組織、皮膚組織和軟骨都是「成體幹細胞」來源。
泰勒的研究還有一項令人興奮的發現，就是人類心臟細胞會隨著附著支架不同，改變其功能，如移入肝臟支架，心臟細胞就作用得像肝細胞，較不像心臟細胞。

利用支架已有前例

 

泰勒團隊的成績非一枝獨秀，美國耶魯大學生物醫學工程學教授尼克拉森去年在《科學》期刊發表報告，其團隊用和泰勒類似方法，育出數枚老鼠肺臟；上個月，美國北卡羅萊納州的再生醫學教授索克也用動物肝臟支架，育出迷你尺寸的人類肝臟。

http://tw.nextmedia.com/applenews/article/art_id/33296780/IssueID/20110405

Stem Cells Help Grow Live Human Heart

Scientists are growing human hearts in laboratories with the help of stem cells, giving hope to millions of cardiac patients around the world.

Researchers at the University of Minnesota in Minneapolis believe the lab-developed organs could start beating in a matter of weeks. It’s a huge step towards the first ‘grow-your-own’ heart, and could lead the way into producing other organs such as livers, lungs and kidneys.

The researchers created the organs by removing muscle cells from donor organs. They injected stem cells which multiplied and grew around the structure, eventually forming healthy heart cells.

“The hearts are growing, and we hope they will show signs of beating within the next weeks,” said Dr. Doris Taylor, an expert in regenerative medicine at U of M, according to the Daily Mail.

The artificial organs have been created using immature ‘master cells’ which have the ability to turn into other types of tissue. This latest experiment follows a series of successful experiments researchers have accomplished in the goal to create artificial organs for potential use in transplants.

Taylor and colleagues have already created beating rat and pig hearts. Although the organs were not strong enough to use in animals, the research proved to be a major step in the goal of producing tailor-made organs.

The researchers reported their latest study results at the American College of Cardiology’s annual conference in New Orleans.

The team used human hearts taken from dead bodies to create the lab-grown hearts. They stripped the cells from the dead hearts using a powerful detergent, leaving ‘ghost heart’ scaffolds made from collagen protein.

The researchers injected the ghost hearts with millions of stem cells -- extracted from patients -- and supplied with nutrients. The stem cells recognized the collagen heart structure and began to turn it into heart muscle cells. Although the hearts have yet to begin beating, the team believes that when they do, they could be strong enough to pump blood.

However, there are many obstacles obstructing scientists from creating working hearts. One of the biggest obstacles is getting enough oxygen to the heart through a complex network of blood vessels. Scientists will also need to ensure that the heart cells beat normally.

“We are a long way off creating a heart for transplant, but we think we’ve opened a door to building any organ for human transplant,” Taylor told the Sunday Times.

http://www.redorbit.com/news/health/2024177/stem_cells_help_grow_live_human_heart/