Amnion-Derived Teno-Inductive Secretomes: A Novel Approach to Foster Tendon Differentiation and Regeneration in an Ovine Model

Maria Rita Citeroni; Annunziata Mauro; Maria Camilla Ciardulli; Miriam Di Mattia; Mohammad El Khatib; Valentina Russo; Maura Turriani; Michael Santer; Giovanna Della Porta; Nicola Maffulli; Nicholas R Forsyth; Barbara Barboni

doi:10.3389/fbioe.2021.649288

Amnion-Derived Teno-Inductive Secretomes: A Novel Approach to Foster Tendon Differentiation and Regeneration in an Ovine Model

Front Bioeng Biotechnol. 2021 Mar 11:9:649288. doi: 10.3389/fbioe.2021.649288. eCollection 2021.

Authors

Affiliations

¹ Unit of Basic and Applied Biosciences, Faculty of Bioscience and Agro-Food and Environmental Technology, University of Teramo, Teramo, Italy.
² Department of Medicine, Surgery and Dentistry, University of Salerno, Salerno, Italy.
³ School of Pharmacy and Bioengineering, Keele University School of Medicine, Stoke-on-Trent, United Kingdom.
⁴ Research Centre for Biomaterials BIONAM, University of Salerno, Fisciano, Italy.
⁵ Centre for Sports and Exercise Medicine, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, United Kingdom.

Abstract

Regenerative medicine has greatly progressed, but tendon regeneration mechanisms and robust in vitro tendon differentiation protocols remain to be elucidated. Recently, tendon explant co-culture (CO) has been proposed as an in vitro model to recapitulate the microenvironment driving tendon development and regeneration. Here, we explored standardized protocols for production and storage of bioactive tendon-derived secretomes with an evaluation of their teno-inductive effects on ovine amniotic epithelial cells (AECs). Teno-inductive soluble factors were released in culture-conditioned media (CM) only in response to active communication between tendon explants and stem cells (CM_CO). Unsuccessful tenogenic differentiation in AECs was noted when exposed to CM collected from tendon explants (CM_FT) only, whereas CM_CO upregulated SCXB, COL I and TNMD transcripts, in AECs, alongside stimulation of the development of mature 3D tendon-like structures enriched in TNMD and COL I extracellular matrix proteins. Furthermore, although the tenogenic effect on AECs was partially inhibited by freezing CM_CO, this effect could be recovered by application of an in vivo-like physiological oxygen (2% O₂) environment during AECs tenogenesis. Therefore, CM_CO can be considered as a waste tissue product with the potential to be used for the development of regenerative bio-inspired devices to innovate tissue engineering application to tendon differentiation and healing.

Keywords: amniotic stem cells; co-culture; conditioned media; tendon; tendon-differentiation; tissue engineering.