“Latest Stem Cells News”

A new report brings bioengineered organs a step closer, as scientists from Stanford and New York University Langone Medical Center describe how they were able to use a “scaffolding” material extracted from the groin area of mice on which stem cells from blood, fat, and bone marrow grew. This advance clears two major hurdles to bioengineered replacement organs, namely a matrix on which stem cells can form a 3-dimensional organ and transplant rejection.

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It raises hopes that kidney disease patients will one day be able to grow their own new organs with no risk of rejection.

Kidneys 5mm long – the size of those in foetuses – were made using a combination of cells from amniotic fluid, which surrounds babies in the womb, and animal foetal cells.

It is hoped the organs could be grown to maturity if implanted in a patient. In future, people’s amniotic fluid could be retained at birth, allowing it to be used later if they develop kidney disease.

‘The idea is to start with human stem cells and end up with a functioning organ,’ said physiologist professor Jamie Davies, whose University of Edinburgh team carried out the work.

‘We are working on how you turn cells floating about in liquid into something as precisely arranged as a kidney. We have made pretty good progress with that.

‘We can make something that has the complexity of a normal, foetal kidney but not an adult one yet.’

Stem cell technology could be ready for use on humans in about ten years, he said.

A US team has already shown a foetal kidney can be put into an adult animal and grown there. About 7,000 people are on the waiting list for kidney transplants but there is a serious shortage of the organs.

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From left to right: A normal pig heart, a pig heart after being decellularised, the pig heart prepared for recellularisation. Photos courtesy of the University of Minnesota.

In a medical first, University researchers have created a beating heart in the laboratory. Using detergents, they stripped away the cells from rat hearts until only the nonliving matrix, or “skeleton,” was left; they then repopulated the matrix with fresh heart cells.

If perfected, the technique may be used someday to generate new hearts for patients. In the United States alone, about 5 million people live with heart failure, 550,000 new cases are diagnosed every year, and 50,000 die waiting for a donor heart.

“The results were a home run,” says Doris Taylor, director of the University’s Center for Cardiovascular Repair and a principal investigator on the study. “We knew that cell therapy–that is, transplanting cells into [a patient's damaged] heart–is not a panacea. So we started thinking, ‘Is there a way to use cells to engineer heart tissue?’”

The idea, she says, is to create whole new blood vessels or organs by implanting a patient’s own cells into a matrix derived from a donor organ. This approach ought to bypass the problem of organ rejection because the matrix, being devoid of cells, shouldn’t provoke an immune response. Even if it did, the new cells would create a fresh matrix of their own, which would turn off the immune response and free patients from the need to take immunosuppressive drugs.

The process, called whole organ recellularization, can be done “with virtually any organ,” Taylor says.

A simple plan

The main hurdle in creating new hearts wasn’t finding the right cells but recreating the vastly complex architecture of the heart, Taylor explains. In puzzling it over, she and Harald Ott, a research associate in the center (now a surgical resident at Harvard Medical School and first author of the study), hit on a way to get nature to solve the problem for them.

To remove cells from fresh rat hearts, the researchers pumped solutions of detergents through the network of blood vessels that normally nourish the organ. The treatment popped all the cells like balloons and washed away the debris, leaving the matrix of protein fibers that form the backbone of a living heart’s connective tissue. It’s called the extracellular matrix, or ECM.

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