Scientists are growing human hearts in laboratories, offering hope for millions of cardiac patients.
American researchers believe the artificial organs could start beating within weeks. The experiment is a major step towards the first “grow-your-own” heart, and could pave the way for livers, lungs or kidneys to be made to order.
The organs were created by removing muscle cells from donor organs to leave behind tough hearts of connective tissue. Researchers then injected stem cells which multiplied and grew around the structure, eventually turning into healthy heart cells.
Dr Doris Taylor, an expert in regenerative medicine at the University of Minnesota in Minneapolis, said: “The hearts are growing, and we hope they will show signs of beating within the next weeks. “There are many hurdles to overcome to generate a fully functioning heart, but my prediction is that it may one day be possible to grow entire organs for transplant.”
Patients given normal heart transplants must take drugs to suppress their immune systems for the rest of their lives.This can increase the risk of high blood pressure, kidney failure and diabetes. If new hearts could be made using a patient’s own stem cells, it is less likely they would be rejected.
The lab-grown organs have been created using these types of cells – the body’s immature “master cells” which have the ability to turn into different types of tissue. The experiment follows a string of successes for researchers trying to create spare body parts for transplants.
In 2007, British doctors grew a human heart valve using stem cells taken from a patient’s bone marrow. A year later, scientists grew a beating animal heart for the first time.
Dr Taylor’s team has already created beating rat and pig hearts. Although they were too weak to be used in animals, the work was an important step towards tailor-made organs.
In their latest study, reported at the American College of Cardiology’s annual conference in New Orleans, researchers created new organs using human hearts taken from dead bodies. The scientists stripped the cells from the dead hearts with a powerful detergent, leaving “ghost heart” scaffolds made from the protein collagen.
The ghost hearts were then injected with millions of stem cells, which had been extracted from patients and supplied with nutrients. The stem cells “recognized” the collagen heart structure and began to turn into heart muscle cells. The hearts have yet to start beating – but if they do, they could be strong enough to pump blood.
However, the race to create a working heart faces many obstacles. One of the biggest is getting enough oxygen to the organ through a complex network of blood vessels. Scientists also need to ensure the heart cells beat in time.
Dr Taylor told the Sunday Times: “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.”
Extracted from: http://www.dailymail.co.uk
Nuno Costa
Cada vez mais o ser humano recorre à ciência para diagnóstico e tratamentos de várias efemeridades que assolam a vida humana. A essência do ser humano reside nas células e nos tecidos que constituem o organismo vivo a que chamamos Homem.
ResponderEliminarNesta pequena notícia verifica-se que o Homem já está a transpor barreiras que à algumas décadas atrás consideraríamos como pura ficção. Pois bem, essa ficção através dos tempos tornou-se realidade dando origem a uma nova vertente científica – a medicina regenerativa. Aqui podemos constatar que uma simples organização das células numa matriz extracelular, denominado na notícia como “ghost heart” em cultura "in vitro" dá origem a um novo tecido funcional que por sua vez formará um órgão. As experiências evolutivas nesta área permitiram a concepção de órgãos que muitas vezes não estão ao nosso alcance quando mais precisamos devido à falta de dadores de órgãos, que consigo trazem enormes listas de espera em cirurgias. E quando existe um órgão, muitas vezes não é compatível levando-nos ao mesmo problema. Assim sendo, surge em primeira mão a criação de um dos principais órgãos do nosso corpo – o coração. Ainda em estudos muitos promissores elaborados em ratos, verificaram a funcionalidade do novo coração quer ao nível da pressão arterial quer nos intervalos de duração dos batimentos cardíacos.
Resumindo, penso que dentro de alguns anos, mais próximo do que pensamos, teremos em mão um novo coração artificial para pessoas que urgentemente necessitam dele sem que haja risco de incompatibilidade e quem sabe um dia, o cérebro artificial deixará de ser uma ficção!
Nuno Costa