Controlling stem cells in the lab

Scottish scientists have discovered a way to replicate the regenerative power of stem cells in the lab, preventing them from differentiating over a prolonged period. Their work has been published in the journal ACS Nano.

Mesenchymal stem cells are produced naturally in the body and have the ability to develop, or ‘differentiate’, into many other different types of cells, such as bone, cartilage or fat cells. They typically wait in the bone marrow until a regenerative demand is placed on them, at which point they change into mature cell types to repair the bone, cartilage, ligament or tendon around them.

Stem cells have enormous potential for use in medicine but are difficult to properly culture in the laboratory, because when stored outside of the body they spontaneously and randomly differentiate. This is the process that the researchers from the University of Glasgow, led by Dr Catherine Berry and Professor Matthew Dalby, have been working to prevent.

To achieve their goal, the researchers added magnetic nanoparticles to each stem cell. Then, using a simple magnet, they built ball-shaped masses of around 10,000 stem cells, just big enough to see with the naked eye, over the course of just a few hours. When placed in soft gel, similar to the consistency of bone marrow jelly, these balls of cells remain as stem cells over long culture periods, with no unwanted differentiation.

The researchers placed the 3D spheroid cultures next to laboratory wound models of cartilage, bone and ligament. When the bundles of stem cells were placed next to the injured area, they quickly became active again: they migrated towards the injured tissue and began to differentiate in the same way they would in the human body to heal a wound.

“This is a really exciting discovery, which uses a fairly simple and affordable method to grow and maintain stem cells ready to heal tissues,” stated Dr Berry, who said the researchers are “keen to explore how we can use our technique to understand more about how stem cells communicate with other cells and what we can do to use stem cells more effectively in medicine”.

The team has already started to work with the Paul O’Gorman Leukaemia Research Centre and the Beatson West of Scotland Cancer Centre to look at the potential to use this technique to combat leukaemia and breast cancer — diseases which can hide bundles of cancer cells in the bone marrow. These “lay dormant for years before being becoming active again”, said Dr Berry, “causing secondary cancers which are often very difficult to treat”.

“It may be that changes in mesenchymal stem cell activity are linked to cancer cell activation,” she suggested.