Speaker：Anqi Yu（于安琪）Yifei Weng（翁翊菲）Minming Wang（王闽铭）Xiaohe Xie（谢霄鹤）

Time：10:00 - 13:00

Cut the skin and it will bleed. Within three weeks of the injury occurring, the wound has healed. These quick repairs often result in scars, particularly when the wound is deep. When such repairs to skin are small, they don’t pose much of a problem. But as scar tissue doesn’t have the stretch and the mobility and the range of motion that normal skin does, big scars can be life-changing.

However, scarring might not be inevitable. Fetal skin begins to scar only late in gestation, which suggests that human skin possesses at least some regenerative capabilities. Fetal wounds are not the only wounds that are resistant to scarring. Scientists have found that older people often develop thinner scars than do younger adults¹. Further experiments revealed the probable culprit: Cxcl12, a gene that encodes a protein called stromal cell-derived factor 1 (SDF1). When the team knocked out SDF1, even wounds in young animals healed with minimal scarring. Fibroblasts are another prominent player. These cells have long been blamed for scar tissue. Scientists have found that only one of two lineages of fibroblast — expressing homeobox protein engrailed-1 — was responsible for the formation of most scar tissue². And when the team disabled those cells in mice, wounds healed more slowly but also formed less scar tissue, similar to what happened in mice that lack SDF1.

Many discoveries are made and involve many factors including immune cells, age, fat, etc. They make the question even more complex. Although there are some medicines used clinically to bring wound-healing therapies, the main goal of these treatments is to promote better healing, rather than to prompt skin to regenerate. Achieving that next step — scar-free healing — is a tall order to fill.

Guest information:

1. Sun, Bryan K., Zurab Siprashvili, and Paul A. Khavari. "Advances in skin grafting and treatment of cutaneous wounds." Science 346.6212 (2014): 941-945.

DOI: 10.1126/science.1253836

2. Rinkevich, Yuval, et al. "Identification and isolation of a dermal lineage with intrinsic fibrogenic potential." Science 348.6232 (2015): aaa2151.

DOI: 10.1126/science.aaa2151