Karolinska: Breakthrough in stem cell culturing

Research lead

Researchers at the Karolinska Institutet say that for the first time they have cultured human embryonic stem cells under chemically controlled conditions without the use of animal media.

This in an essential step in opening up human embryonic stem cell lines for use in human cell therapies.

While embryonic stem cells can be turned into any other type of cell in the body, it is difficult to culture and develop cells without simultaneously contaminating them. Many existing cell lines were raised in animal cell culture, ruling out subsequent use in humans. Alternatively, stem cells can be cultured on other human cells, known as feeder cells, but these release thousands of uncontrolled proteins, leading to unreliable research results.

A research team at the Karolinska has now managed to produce human stem cells entirely without the use of other cells or substances from animals. Instead they are cultured on a matrix of a single human protein called laminin-511.

“Now, for the first time, we can produce large quantities of human embryonic stem cells in an environment that is completely chemically defined,” says Karl Tryggvason, who led the study. “This opens up new opportunities for developing different types of cell which can then be tested for the treatment of disease.”

Working with researchers at the Harvard Stem Cell Institute, the researchers have also shown laminin-511 can be used to culture induced pluripotent stem cells from adult cells.

Laminin-511 is protein found in connective tissue and acts in the body as a matrix to which cells can attach. In the newly formed embryo, the protein is also needed to keep stem cells as stem cells. Once the embryo begins to develop different types of tissue, other types of laminin are needed.

Until now, different types of laminin have not been available, because the material is almost impossible to extract from human tissues. Over the last couple of decades, Tryggvason’s research group has cloned the genes for most human laminins and in recent years, managed to produce several types of recombinant laminin.