We frequently write about using synthetic scaffolds and various biomaterials to coax stem cells to become specific tissues in specific shapes, such as for creating a new windpipe. On the surface, these materials seem like steel beams that provide support for a building but don’t really impact the make-up of the walls they are holding up. It turns out the scaffolds can have a bigger role.

A team at the University of California San Diego, led by CIRM-funded Shyni Varghese, published an enlightening example this week in the Proceedings of the National Academy of Sciences. They found that a compound in the scaffold had a direct impact on the metabolism of the stem cells that drove them to become bone.

That compound, calcium phosphate, has been known to help drive stem cells to become bone, but no one knew why or how. So, getting the desired impact has been an inefficient and expensive trial and error effort. Now, researchers have a pathway they can try to manipulate directly to impact hard-too-heal bone fractures and diseases like osteoporosis. A press release from UCSD has a quote from Varghese explaining the importance of knowing this path:

“We knew for years that calcium phosphate-based materials promote osteogenic differentiation of stem cells, but none of us knew why. As engineers, we want to build something that is reproducible and consistent so we need to know how building factors contribute to this end.”

This work echoes a theme I heard yesterday at a talk at the neighboring Gladstone Institutes delivered by Todd McDevitt of Georgia Tech. His work also focuses on the factors needed to get stem cells to become a desired tissue. He developed a system of loading microscopic particles with those factors and embedding them in the clumps of stem cells he wanted to become a specific tissue. It turned out that delivering those factors locally where they could do their job allowed him to use one-tenth the amount of the normal process—dissolving them in the lab culture broth. Since those factors are often the most expensive part of developing a needed tissue, this system could dramatically bring down the cost of research and eventually the cost of developing cell-based therapies.

The current UCSD work only applies to bone, but the team hopes to use this understanding to develop material that can more efficiently drive stem cells to become muscle, blood vessels, or other tissues.

CIRM funding: Shyni Varghese (RN2-00945)

Don Gibbons