Abstract
Purpose:
Application of amniotic membrane suspension (AMS) eye drops is a potential treatment alternative for therapy resistant corneal epithelial defects. The purpose of this study was to determine the concentrations of growth factors EGF, NGF, VEGF, TGFβ1, FGFb, HGF, KGF and interleukins IL-1β, IL-6, IL-8 in AMS following different preparation methods and time periods.
Methods:
Amniotic membranes of 10 placentas were prepared and thereafter stored at -80°C using the standard method of our LIONS Cornea Bank. Following defreezing, amniotic membrane pieces with a standard size were inserted in a 12-well plate either complete or cut in small pieces, and 2000µl DMEM culture medium was added. EGF, NGF, VEGF, TGFβ1, FGFb, HGF, KGF, IL-β1, IL-6 and IL-8 secretion into the culture medium was determined following 8, 48 and 96 hours and, in a new preparation, following 1, 2, 3 and 4 weeks of incubation using enzyme-linked immunosorbent assay (ELISA).
Results:
Secretion of NGF, VEGF, TGFβ1, HGF, KGF and IL-1β was beyond the detection limit at all the time points. For both complete and small-cut membranes, the concentration of EGF increased from 8 hours to 4 weeks (p=0.025), FGFb decreased from 8 hours to 4 weeks (p=0.018). In small-cut membranes, IL-6 concentration increased significantly from 8 hours to 1 week (p=0.012). From 2 to 4 weeks there was again no significant difference to baseline. In complete membranes, IL-6 concentration decreased significantly from 8 hours to 4 weeks (p=0.012). The concentrations of IL-8 over time were similar, but ranged on a higher level than that of IL-6. Comparing complete and small-cut membranes EGF (p>1.95) and FGFb (p>0.34) secretion did not differ significantly from baseline at any time point. A significant difference between both preparation methods was shown for the IL-6 concentration after 8 and 48 hours (p<0.001; p=0.01) and in IL-8 concentration after 8 and 96 hours and after 3 weeks (p=0.02; p=0.002; p=0.027).
Conclusions:
Containing EGF and FGFb, IL-6 and IL-8, amniotic membrane suspension is a potential non-surgical treatment alternative of therapy resistant corneal epithelial defects. However, the most effective preparation method and the optimal harvesting time point is yet to be determined.
Keywords: 490 cytokines/chemokines •
482 cornea: epithelium •
765 wound healing