In the United States alone, approximately 50,000 patients die because of the lack of donor hearts every year. Meanwhile, some 22 million people worldwide are living with the threat of heart failure. If scientists could devise a way to develop transplantable blood vessels or whole organs that are made from human’s own cells, then many lives could be saved.
It seems that this hope should not be too far away, especially when a group of scientists from United States has coaxed recycled hearts taken from animal cadavers into beating in the laboratory after reseeding them with live cells.
The new study was carried out by scientists from the University of Minnesota and their finding was published on January 13, 2008 in the British journal Nature Medicine. There has been research in generating living heart tissue in the laboratory, but this is the first time that an entire, 3-dimensional bio-dimension bio-artificial heart has been brought to life.
If such procedure could be extended to humans, then an almost limitless supply of hearts and possibly many other organs would be made available to millions of terminally ill humans, who are waiting helplessly for a new lease on life.
In the study, a procedure called decellularisation was used. During the procedure, all the cells from an organ (in this case the heart of a dead rat) were stripped away using powerful detergents, leaving only a bleached-white scaffolding composed of proteins secreted by the cells. This matrix was then injected with a mixture of cells taken from the heart of a newborn rat and placed in a sterile laboratory setting, where the scientists hoped it would grow. After only 4 days, contractions started, and on the 8th day, the hearts were pumping. The researchers were stunned when they saw the result. Decellularisation has indeed changed the way scientists think about engineering organs.
In humans, the objective would be to inject stem cells drawn directly from the recipient of the donated organ, thus eliminating the danger of rejection of the new organ by the immune system.
Recent breakthroughs in stem cell research from non-embryo sources would mean that new tissues should be easy to generate. If organs derived from a patient's own cells would become available on a large scale, then millions of patients suffering from organ failure would benefit.
The research team is now working on making the recycled organs more efficient, and has even transplanted some of these hearts into the abdomens of rats and connected them to the animals' aortas, a standard way of testing whether a donor organ can keep an animal alive.
The Minnesota researchers have also successfully applied the new technique to pig hearts, which are closer to human hearts in size and complexity, although this was not reported in the current study.