Maintenance and Acceleration of Pericellular Matrix Formation within 3D Cartilage Cell Culture Models

Abstract

Objective In native articular cartilage, chondrocytes are surrounded by a thin pericellular matrix (PCM) forming chondrons. The PCM is exclusively rich in type VI collagen. The retention of the PCM has a significant influence on the metabolic activity of the chondrocytes. Design This study investigated the influence of 2 hydrogels (hyaluronic acid [HA] and agarose) and 2 media compositions (basal and chondrogenic) on the preservation/maintenance and acceleration of PCM formation over a 21-day time course. Different combinations of chondrocytes, chondrons, and mesenchymal stem cells (MSCs) were studied. Results Both hydrogels preserved chondrons PCM from day 1 up to 21-day culture regardless of media composition. Type VI collagen immunostaining of the cultured chondrons appeared both dense and homogenous. The presence of MSCs did not influence this outcome. At day 1, type VI collagen was not present around chondrocytes alone or their co-culture with MSCs. In the HA hydrogel, type VI collagen was located within the PCM after 7 days in both mono- and co-cultures. In the agarose hydrogel, collagen VI was located within the PCM at 7 days (co-cultures) and 14 days (monocultures). In both hydrogel systems, chondrogenic media enhanced the production of key extracellular matrix components in both mono- and co-cultures in comparison to basal media (11.5% and 14% more in glycosaminoglycans and type II collagen for chondrocytes samples at day 21 culture samples, respectively). However, the media types did not enhance type VI collagen synthesis. Conclusion Altogether, a 3D chondrogenic hydrogel environment is the primary condition for maintenance and acceleration of PCM formation.

Mimicking Loading-Induced Cartilage Self-Heating in Vitro Promotes Matrix Formation in Chondrocyte-Laden Constructs with Different Mechanical Properties

“…Therefore, it was initially hypothesized that a preaccumulated extracellular matrix might better facilitate the transmission of thermomechanical stimulus in the dissipative hydrogels. Previous investigations have shown that a preculture of approximately 5 days is adequate for a significant up-regulation of cartilage-specific genes, such as cartilage oligomeric matrix protein, proteoglycan 4, collagen type II, and aggrecan following a relatively short-term stimulation, as well as for the formation of a pericellular matrix. , We have confirmed these observations by showing that chondrocytes can produce functional proteins (such as collagen type 2) during 5 days of preculture (see supplementary data, page S4). Given that there is currently no available “universal” stimulating protocol and based on the fact that chondrocytes can produce collagen type 2 during 5 days preculture, we decided to proceed with the experimental protocol we used in our previous published study …”

Minced Cartilage Implantation in Acetabular Cartilage Defects: Case Series with 2-Year Results

“…If such a difference exists between minced cartilage and the different available third-generation ACI implants remains to be shown. [28][29][30][31][32] Sustained chondrocyte viability has been demonstrated for innovative mincing techniques with a manual hand device 33 and, lately, with an arthroscopic shaver. 34 Possible benefits of the augmentation with autologous platelet-rich plasma (PRP) are uncertain as PRP showed a dose-and time-dependent positive effect on the proliferation and viability of isolated chondrocytes in vitro 35 but did not have an impact during MCI in an animal model.…”

Enzymatic Isolation of Articular Chondrons: Is It Much Different Than That of Chondrocytes?

“…Chy are known to form a PCM during in vitro culture when embedded in agarose and hyaluronic acid hydrogels. 29,30 When this process is optimized, tissue engineered Chns could be a more homogeneous cell source compared to enzymatically isolated Chns. In this study, partial Chns were defined as cells with a low-intensity type VI collagen staining.…”