Extracellular Matrix Determines Biomechanical Properties of Chondrospheres during Their Maturation In Vitro

Abstract

Objective Chondrospheres represent a variant of tissue spheroids biofabricated from chondrocytes. They are already being used in clinical trials for cartilage repair; however, their biomechanical properties have not been systematically investigated yet. The aim of our study was to characterize chondrospheres in long-term in vitro culture conditions for morphometric changes, biomechanical integrity, and their fusion and spreading kinetics. Results It has been demonstrated that the increase in chondrospheres secant modulus of elasticity is strongly associated with the synthesis and accumulation of extracellular matrix. Additionally, significant interplay has been found between biomechanical properties of tissue spheroids and their fusion kinetics in contrast to their spreading kinetics. Conclusions Extracellular matrix is one of the main structural determinants of chondrospheres biomechanical properties during chondrogenic maturation in vitro. The estimation of tissue spheroids' physical behavior in vitro prior to operative treatment can be used to predict and potentially control fusogenic self-assembly process after implantation in vivo.

Multiparametric Analysis of Tissue Spheroids Fabricated from Different Types of Cells

“…At 6th day TS were fixed in 10% buffered formalin (pH 7.4) and embedded in paraffin (Biovitrum, Russia) and processed as described previously. [ 8 ]…”

“…TS mechanical properties were measured using a micro‐scale parallel‐plate compression testing system Microsquisher (CellScale, Canada) and associated SquisherJoy software as described earlier. [ 8 ] TS with an initial cell number 1000 cells for HEK293 and L6 cell lines and 8000 cells for chondrocytes and HF were formed using Corning spheroid microplates. They were cultured for 1, 2, 3, 6, and 9 days prior to mechanical characterization.…”

“…TS samples on polyurethane electrospun matrix were fixed with 2.5% glutaraldehyde/PBS for 2 h at 4 °C and processed for SEM analysis as described previously. [ 8 ]…”

“…TS with intrinsic multicellular architecture, secreted and deposited specific extracellular matrix (ECM) proteins, including collagen type II and aggrecan in chondrocyte spheroids, [ 7,8 ] collagen types I, III–VIII, X–XII, XVI–XVIII, fibronectin, decorin, fibromodulin, secreted by fibroblasts within fibrospheres, [ 9 ] collagen, vimentin, laminin detected in breast cancer spheroids, [ 10,11 ] represent an established tool for drug efficacy evaluation and alternative to animal testing in drug discovery (DD) and cancer research. [ 12,13 ] Spheroids and cancer lesions both display inherent diffusion‐limited distribution gradient of oxygen, nutrients, metabolites, and signaling molecules.…”

Hyaline cartilage next generation implants from adipose-tissue-derived mesenchymal stem cells: Comparative study on 3D-printed polycaprolactone scaffold patterns

“…Small pieces of the patient's own healthy cartilage are isolated, harvested, and cultivated in the laboratory for the expansion of the chondrocytes. They are finally transplanted arthroscopically as chondrospheres into the cartilage defect, usually with a collagen membrane (Medvedeva et al, ; Omelyanenko et al, ). However, there are drawbacks to this method, such as limited availability of donor sites.…”