Expression pattern of hyaluronan and fibronectin receptors in human granulation tissue

Aim: Fibronectin and hyaluronan (HA) are involved in proliferation and migr ation of cells fron the adjacent tissue into the provisional granulation ti ssue matrix in wound healing. Therefore the aim of our study was to compare the expression pattern of the fibronectin and HA-receptors on fibroblasts in regular healing and chronic wounds. Methods: Biopsies from patients with regular open wound healing (n = 10) an d chronic wounds (n = 10) were taken. A single cell suspension was double l abeled with monoclonal antibodies and investigated by FACS-Analysis (Fibrob lasts: FITC-labeled, alpha4 and alpha5 subunits of fibronectin receptors, G D44-HA-receptor: PE-labeled). The results include the percentage of positiv e fibroblasts and the mean fluorescence intensity. Results: Granulation tissue of normal and chronic human wounds showed a sim ilar high distribution pattern of the HA-receptor CD44 on fibroblasts. The alpha4 and alpha5 subunits of fibronectin receptors were significant increa sed in chronic wounds by their n umber of positive cells and mean fluoresce nce intensity. Conclusion: The high levels of CD44 positive fibroblasts explain the improv ed wound healing by HA in regular and chronic wounds. An altered matrix due to the increased presence of proteases in chronic wounds and the resulting digestion of the fibronectin matrix could explain the high expression of f ibronectin receptors.