Studies in fetal wound healing: I. A factor in fetal serum that stimulates deposition of hyaluronic acid.

Fetal wound healing without scar formations, fibrosis, or contracture might be accompanied by major differences in the wound extracellular matrix. The matrix of fetal wounds is rich in hyaluronic acid, a glycosaminoglycan found in high concentrations whenever there is tissue proliferation, regeneration, and repair. Although hyaluronic acid is a critical molecule for both embryonic development and wound healing, no factor has yet been identified that modulates hyaluronic acid in a consistent manner. We describe here a substance present in fetal sheep serum that stimulates hyaluronic acid synthesis by cultured fibroblasts. This glycoprotein factor appears to be ubiquitous, present in fetal sheep and bovine serum, reaching a peak in each at 40% of the way through gestation. This factor is also present in amniotic fluid. It might control hyaluronic acid deposition. In turn, hyaluronic acid, by creating an extracellular environment permissive for cell motility and proliferation, might be critical for fetal development. We suggest that the same sequence of events underlie the unique properties observed in fetal wound healing.