Nerve growth factor modulates in vitro the expression and release of TGF-beta1 by amniotic membrane.

Purpose To determinate the basal production of NGF and TGF-â1 by amniotic membrane (AM) and to verify the presence of NGF receptors (trkANGFR and p75NTR) in AM. Thereafter, to evaluate in an in vitro model if increasing concentrations of NGF are able to stimulate AM to produce and release TGF-â1. Methods Immunohistochemistry, ELISA, in situ hybridization and PCR analysis for NGF, TGF-â1, trkANGFR and p75NTR were performed to study their presence in AM. Amniotic membranes were stimulated in vitro with increasing concentrations of NGF. After 24 h, the amount of TGF- â1 in the AM tissue and in the culture medium was investigate. Results AM expressed TGF-â1, NGF, trkANGFR and p75NTR mRNAs and proteins and released basal amounts of NGF and TGF-â1 in the medium. Stimulation of AM by addition of NGF induced a significant (P<0.05) increase of TGF-â1 mRNA/protein in AM tissue as well as a release of TGF-â1 protein into the culture medium, in a dose-dependent fashion. Conclusions This study demonstrates that amniotic membrane releases basal amounts of NGF and TGF-â1 and expresses NGF receptors . Moreover, the addition of NGF to the culture medium stimulates the amniotic membrane to significantly increase the production and release of TGF-â1.