Anyone who is injured hopes for a speedy recovery. But wounds that heal too quickly can heal badly: if the concentration of certain growth factors becomes too high and the healing process overshoots the mark, then bulging (in technical jargon: hypertrophic) scars form and even the surrounding skin loses some of its elasticity. This is the conclusion that Sabine Werner, at the Institute for Molecular Health Sciences, and Edoardo Mazza, at the Institute for Mechanical Systems, and their two research groups have reached following joint investigations.
Complex interactions
As the researchers just reported in the journal
Nature Communications
, they have deconstructed the complex mechanisms that control the process of tissue repair (and scar formation) in more detail. Their current work, which was made possible by University Medicine Zurich’s flagship project Skintegrity (see box), focuses on a signal molecule: activin. This molecule plays an important role both in healing wounds and in cancer. “We’ve shown how profoundly a single signal molecule affects the complex interaction between cells and their surroundings,” Werner says.
The greater the quantity of activin in the wound, the more connective tissue cells are generated. Higher activin concentrations also change the composition of what is known as the extracellular matrix, the scaffold surrounding the cells of the wound. In this scaffold, which is produced and remodelled by the cells, higher activin concentrations translate into greater accumulation of collagen, and the collagen fibres are also more strongly cross-linked with each other. While this promotes the speed of wound healing, it also causes the injured tissue to stiffen and harden.
Influencing the healing process
