Growing Bones

It would be wonderful if we could control our fate and alter what we will become. Sadly, at least on a cellular level, that isn't possible. But although we can't engineer ourselves (not just yet, anyways), we can control the fate of stem cells—at least to a certain degree. And thanks to a new breakthrough, we may have a way of using these cells in order to regenerate and grow bone.

Recently, researchers from Harvard announced that they had developed a new technique for precisely controlling the development of stem cells and their eventual growth into bone cells. This method essentially allows us to change the fate of individual stem cells.

Lead researcher David Mooney notes the importance of this development in the press release, saying, "This work both provides new insight into the biology of regeneration, and is allowing us to design materials that actively promote tissue regeneration."

The effect is achieved by putting stem cells into a viscoelastic microenvironment similar to that of natural extracellular matrices. The researchers then tune the rate at which the gel relaxes to direct the fate of the stem cell.

Postdoctoral fellow in the lab and co-first author Luo Gu clarifies the research: “We found that with increasing stress relaxation, especially combined with increased stiffness in the hydrogel, there is an increase of osteogenic — bone cell — differentiation. With increased stress relaxation, there was also a decrease in the differentiation into fat cells. This is the first time we’ve observed how matrix stress relaxation impacts stem cell differentiation in 3D.”

Growing Forward

Increased stress relaxation dramatically increased early osteogenic differentiation in the stem cells and, most notably, allowed them to continue to grow as bone cells after the initial differentiation, forming an interconnected mineralized matrix rich in collagen, the key structural features of bone.

Ultimately, this provides a new way to control stem cell differentiation and development - and to control it with increased precision. The next stage of the research is to test fast-relaxing hydrogels in vivo, to see if they promote bone healing.


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