International Conference onStem Cells, Regenerative Medicine and Tissue Engineering

Title: Assessment of the enhanced functional paracrine effect of amniotic epithelial stem cells when cultured on 3D biomimetic scaffolds: An in vitro model to simulate tendon regeneration

Abstract:

Statement: Tendon disorders pose a considerable challenge in regenerative medicine primarily because of the tissue's limited ability to heal and for the inefficacy of current therapies (1). Successful tendon regeneration requires a tuned regulation of the interactions among the immune system, blood vessels, and somatic/progenitor cells involved in extracellular matrix (ECM) remodeling. The coordination of these three components is essential for the advancement of tissue engineering (TE) strategies aimed at improving tendon regeneration. Recent advances in regenerative medicine highlight the crucial role of paracrine-mediated intercellular communication between stem cells, as an amniotic epithelial stem cell source, and tissue repair processes (2,3). These findings underscore a novel aspect of scaffold-based TE, stressing the necessity to investigate their paracrine inductive effects on stem cells to anticipate their safety and effectiveness before progressing toward preclinical and clinical translation. Particularly in the context of tendon TE, this aspect has not been systematically studied before.
Aim: the present study aimed to investigate whether a validated 3D PLGA scaffold, designed to mimic the hierarchical architecture and mechanical properties of native tendons (4), could stimulate engineered amniotic epithelial cells (AECs) to release paracrine molecules.
Methodology & Experimental Plan: The conditioned media (CM) derived from AECs-engineered fleeces (AECs-2D) and 3D scaffolds (AECs-3D) were characterized and tested in vitro for their biological impact on target cells representing three key systems for tendon regeneration: human umbilical vein endothelial cells (HUVECs), two types of immune cells (Peripheral Blood Mononuclear Cells (PBMCs) and Jurkat reporter cells), and stem cells with a tendency for tenogenic differentiation (AECs) (2,3). This setup aimed to replicate, in a culture setting, the processes of blood vessel formation, immunomodulation, and tenogenic differentiation, respectively.
Results: The findings highlight the significant influence of scaffold topology and topography on modulating the paracrine profile of the cells. Specifically, AECs cultured on 3D scaffolds exhibited enhanced basal release of bioactive molecules, particularly VEGF-D, b-FGF, RANTES, and PDGF-BB (p < 0.0001 vs. control). Furthermore, biological assays demonstrated that 3D scaffolds proactively potentiated the inhibitory paracrine effect of AECs on PBMCs proliferation (CM3D vs. control, p < 0.001) and LPS-induced Jurkat cell activation compared to controls (CM3D and CM2D vs. control, p < 0.01 and p < 0.05, respectively), without displaying any pro-angiogenic effect on promoting HUVECs proliferation and tubule formation. The teno-inductive paracrine capability of AECs engineered on 3D scaffolds was confirmed through co-culture experiments, resulting in the formation of tendon-like structures. These structures exhibited upregulation of tendon-related genes (SCX, THBS4, COL1, and TNMD) and expression of TNMD and COL1 proteins (5).
Conclusion & Significance: In conclusion, this research highlights the pivotal role of tendon 3D mimetic scaffolds in creating a tailored microenvironment capable of instructing the paracrine-mediated regenerative potential of amniotic epithelial stem cells. This orchestrated environment facilitates effective tendon regeneration by modulating cellular behavior and promoting communication between engineered stem cells and different subpopulations within the injured tendon.

Biography:

Valentina Russo is a Full Professor of Anatomy at the University of Teramo. Valentina is the coordinator of the PhD program in Cellular and Molecular Biotechnology. Her research interests mainly focus on amniotic epithelial stem cells and their application in regenerative medicine and tissue engineering, particularly for tendon therapy. She is the Principal Investigator of national (PRIN, FIRB, PNRR) and European (H2020-MSCA) research projects, particularly leading the H2020-MSCA-ITN EJD-2020-P4 FIT project (Perspectives For Future Innovation in Tendon repair). She has built her university commitment after years of experience in research, evaluation, teaching, and administration in academic institutions.