Detection of matrix metalloproteinases after seeding a decellularized extracellular matrix with chondrogenic progenitor cells

Introduction:

Decellularized extracellular matrix (DECM) from a porcine nasal cartilage is a promising material for cartilage reconstruction. For chondrogenic progenitor cells (CPC) to migrate into a tissue, cells need proteolytic enzymes such as matrix metalloproteinases (MMPs), which can cleave the extracellular matrix. The aim of this study was to evaluate if chondrogenic progenitor cells, seeded on DECM, secrete MMPs in an active or inactive variant.

Methods:

Chondrogenic progenitor cells (a pool of 3 donors), isolated from resected human nasal cartilage, were seeded on 5 processed and 5 unprocessed scaffolds and cultivated for 42 days. Scaffolds were processed with a falling metal globe to produce fissures which facilitate cell migration into the scaffold. On days 5, 26, 33 and 42 samples from the cell culture supernatant from three independent experiments were analyzed. The concentrations of MMP-1, -2, -3, -7, -8, -9, -10, -12 and -13 were measured with multiplex immunoassays and activity analyzed using a fluorescence based activity assay.

Results:

MMP-8 and MMP-9 were not detectable at physiological concentrations, neither in treated nor untreated scaffolds. MMP-12 was only detectable in treated scaffolds. MMP-7 was detected in both types of scaffolds in similar concentrations. All other MMPs were detected at significant lower concentrations in supernatants of untreated scaffolds than in supernatants of treated scaffolds. Overall the measured activity of secreted MMPs was very low.

Conclusions:

Our in-vitro experiments indicated that CPCs, seeded on a DECM, secrete MMPs, yet in an inactive form. Hence, in vitro MMPs have no impact on cell migration. Activation of MMPs could significantly improve the recolonization process of DECM.

Publication History

Publication Date:
23 April 2019 (online)