Mapping of proteomic profile and effect of the spongy layer in the human amniotic membrane

The graft of human amniotic membrane (HAM) contributes to the healing of corneal perforating ulcers and so to save a large number of eyes suffering of severe chemical burns. This biological material is used for the treatment of ocular surface diseases because of its capacity to reduce inflammation and promote a quicker wound healing. For clinical use, the HAM is denuded from its spongy layer, but this layer can be an important source of growth factors which promote re-epithelialization. The aim of our study is to provide a general view of protein expression of the HAM and the spongy layer and therefore to determine if the spongy layer and/or a specific part of HAM have a beneficial role in the process of wound healing in patients with corneal ulcers. For this study, human placentas were obtained from healthy women after vaginal delivery or caesarean section after signing the consent form. Mapping of protein expression is done by dividing the placenta in 2 equal parts, one with spongy layer and another without (conventional HAM). Each part is also divided in 3 zones depending on the distance from the umbilical cord. The proteomic analysis was done by ELISA, targeting growth factors (EGF, HGF, KGF, NGF and TGF-beta1) and pro inflammatory cytokine TNF-α in the HAM without spongy layer and in the spongy layer. In this study we observed significant difference in the total amount of protein extract between the different donors. We do not observe a significant difference in the growth factor level between the conventional HAM and the spongy layer. No variation was observed in the expression of HGF, KGF and NGF in different zone of HAM and neither between conventional HAM and spongy layer in each zone. (*p value < 0.05, **p value<0.01,***p value < 0.001). We do detect very low dose of TNF-α and no correlation with the amount of growth factors. In our study we demonstrated that keeping the spongy layer in conventional method of handling HAM can add more GF, and so probably have a positive affect the wound healing process. Variation in some growth factors expression has been observed between the placentas and therefore this may explain the variation in clinical results. No indicator for the selection of placentas with a higher rate of growth factor was found.