In vitro analysis of adhesion molecule expression and gel contraction of human granulation fibroblasts

The objective of this study was to determine whether human fibroblasts obtained at different times from normally healing wounds were phenotypically distinct with respect to cell-matrix interactions. We cultured human granulation fibroblasts obtained from repeated biopsies from the same punch area. On days 3, 6, 9, and 14 the expression of key adhesion molecules and extracellular matrix components at the protein level by flow cytometry analysis were compared with quiescent fibroblasts. Intercellular adhesion molecule-1 levels were significantly elevated only around day 3, which implies a phenotypic change during the early phase of wound healing. Homing cell adhesion molecule, as well as the alpha4 integrin subunit (CD49d), were essentially unaltered. The alpha5 integrin subunit (CD49e), which imparts the specificity of the fibronectin receptor and alphav (CD51), a vitronectin receptor component, are upregulated around days 3 and 6; the alpha2 and 3 integrin subunits (CD49b/c) were only increased on day 6. In granulation fibroblasts, at days 3 and 14, the level of the beta1 integrin subunit was enhanced. In addition, collagen gel contraction with granulation fibroblasts increases constantly from day 3 to day 14. These results show that human granulation fibroblasts differentially express cell surface adhesion molecules depending on the age of the healing wound. Further, changes in the ability of these cells to contract collagen gels indicate a synchronicity between wound bed contraction and different stages of wound healing.