Scientists have developed a method that allows them to propagate human embryonic stem cells without harming the embryo.
Stem cell research is a pretty controversial area. The best stem cells for medical research purposes are pluripotent stem cells; that is, stem cells that can become almost any other type of cell. These can be obtained in one of two ways: by reprogramming adult cells; or by harvesting a fertilised human embryo — a process that many find alarming, since it destroys the embryo in the process.
Human embryonic stem cell research is, therefore, banned in many places around the world, based on the belief that the destruction of an embryo is equivalent to the destruction of a human life. But what if the embryo could survive the process?
An international collaboration led by Karl Tryggvason, Professor of Medical Chemistry at Karolinska Institutet in Sweden, together with Professor Outi Hovatta at Karolinska Institutet, has developed a method that allows them to grow human embryonic stem cells from a single harvested cell, which an embryo can survive.
"We know that an embryo can survive the removal of a single cell. This makes a great ethical difference," Professor Tryggvason said.
Removing a single cell from an eight-cell embryo is a process that is often employed during IVF to check for potential hereditary diseases, since the egg is fertilised outside of the uterus. If the embryo is given the all-clear, it is then implanted.
What the team has done is take this process and, instead of simply performing genetic testing, set about cultivating the harvested cell. This has been tried before on beds of animal and human protein cells, but this method contaminated the stem cells. Professor Tryggvason's team used a human laminin protein called LN-521 and membrane protein E-cahedrin, both of which are usually associated with pluripotent stem cells. This allowed the embryonic stem cells to propagate without differentiation, or, changing into another type of cell.
Growing — rather than harvesting — embryonic stem cells means that there can be greater access to cells that can grow into heart cells, muscle cells, myelin cells, insulin-producing cells and many others.
"We can cultivate the stem cells in a chemically defined, clinical quality environment. This means that one can produce stem cells on a large scale, with the precision required for pharmaceutical production," Professor Tryggvason said. "Using this technology the supply of human embryonic stem cells is no longer a problem. It will be possible to establish a bank where stem cells can be matched by tissue type, which is important for avoiding transplants being rejected."
You can read the full results of the study "Clonal culturing of human embryonic stem cells on laminin-521/E-cadherin matrix in defined and xeno-free environment" online in the journal Nature.