The influence of decellularized cartilage extracellular matrix on differentiation and polarization of primary monocytes and macrophages

Introduction:

Little is known on the interaction of the porcine nasal decellularized cartilage extracellular matrix (DECM) with monocytes and macrophages. Macrophages (M0) can polarize into M1 (pro-inflammatory) or M2 (anti-inflammatory) phenotypes. Previously, the effect of DECM on the monocyte cell line THP-1 was compared to the effect of other transplant materials (Parietex). Here we further examined, if these results were applicable to primary monocytes.

Methods:

Primary monocytes (CD14+, 5 × 10⁵ cells/DECM) were isolated from blood samples of five healthy donors. M0 macrophages were obtained by incubating the cells in presence of PMA for 24 hours. The monocytes/macrophages were cultured on DECM for 48, 96 and 120 hours. To show the ability of M0 macrophages to polarize into M1 or M2 phenotypes, the cells were further treated with IFN-γ and LPS or IL-4 and IL-13 respectively. These polarized cells were used as a positive control for M1 and M2 markers, which were analyzed using immunological and molecular biology methods.

Results:

As previously seen with the THP-1 cell line, DECM did not induce differentiation of primary monocytes into macrophages. Following the incubation of DECM with macrophages both phenotypes were detected, similar to the observations with THP-1.

Conclusion:

We were able to demonstrate that DECM does not induce differentiation of primary monocytes into macrophages, which points to low immunogenicity of DECM. However, since the incubation of M0 macrophages with DECM led to their polarization into both M1 and M2 phenotypes, animal experiments will be required to draw final conclusions on the inflammatory potential of the matrix.

Publication History

Publication Date:
23 April 2019 (online)