Repair kinetics of amnion cells after microsurgical injury

Objective: There is a paucity of data regarding healing of fetal membranes, We assessed the repairing ability of a microsurgically-injured monolayer of amnion-derived cells compared to an endothelial cell line. Materials and Methods: Amnion-derived cells (FL cells) were grown to confluence in 10% fetal calf serum (FCS), A microsurgical incision was performed under an inverted microscope, The area of each incision was measured at times 0, 6, 12 and 24 h using MCID M4 image analysis software, The experiments were repeated using 1% FCS, The observations were also made replacing the media at 6 and 12 h, Umbilical-cord-derived endothelial cells were used for comparison, The rate of repair of the incision was measured using three methods: (a) absolute closure rate (ACR): (A(0)-A(1))/T, where A(0) is the original incisional area, and A(1) is the new area at interval T; (b) relative percentage rate (RPR): (A(0)-A(1))/A(0)/T x 100, and (c) healing rate (HR): (A(0)-A(1))/A(0) x 100, Results: Amnion cells were capable of repairing the microsurgical defect. The ACR decreased over time, and was higher with larger defects, A lower concentration of FCS nor the addition of fresh media altered the repair process significantly, Endothelial cells were significantly faster than amnion cells or amnion-supplemented cells with endothelial media, The RPR remained relatively constant for all groups, suggesting Gompertzian kinetics, Conclusions: Amnion cells are capable of repairing a surgical defect at a relatively constant percent rate, but are slower than an endothelial cell line. The decreased rate of closure over time may be due to relative-contact inhibition, Further studies will concentrate on the molecular and cellular mechanisms involved in this process.