In VitroAnalysis of Cartilage Regeneration Using a Collagen Type I Hydrogel (CaReS) in the Bovine Cartilage Punch Model

Abstract

Objective Limitations of matrix-assisted autologous chondrocyte implantation to regenerate functional hyaline cartilage demand a better understanding of the underlying cellular/molecular processes. Thus, the regenerative capacity of a clinically approved hydrogel collagen type I implant was tested in a standardized bovine cartilage punch model. Methods Cartilage rings (outer diameter 6 mm; inner defect diameter 2 mm) were prepared from the bovine trochlear groove. Collagen implants (± bovine chondrocytes) were placed inside the cartilage rings and cultured up to 12 weeks. Cartilage-implant constructs were analyzed by histology (hematoxylin/eosin; safranin O), immunohistology (aggrecan, collagens 1 and 2), and for protein content, RNA expression, and implant push-out force. Results Cartilage-implant constructs revealed vital morphology, preserved matrix integrity throughout culture, progressive, but slight proteoglycan loss from the "host" cartilage or its surface and decreasing proteoglycan release into the culture supernatant. In contrast, collagen 2 and 1 content of cartilage and cartilage-implant interface was approximately constant over time. Cell-free and cell-loaded implants showed (1) cell migration onto/into the implant, (2) progressive deposition of aggrecan and constant levels of collagens 1 and 2, (3) progressively increased mRNA levels for aggrecan and collagen 2, and (4) significantly augmented push-out forces over time. Cell-loaded implants displayed a significantly earlier and more long-lasting deposition of aggrecan, as well as tendentially higher push-out forces. Conclusion Preserved tissue integrity and progressively increasing cartilage differentiation and push-out forces for up to 12 weeks of cultivation suggest initial cartilage regeneration and lateral bonding of the implant in this in vitro model for cartilage replacement materials.

Fabrication and characterization of microstructure-controllable COL-HA-PVA hydrogels for cartilage repair

“…Based on the IHC and molecular biology in vivo analysis, the COL-HA-PVA hydrogels promoted the repair of cartilage defects, and hydrogels seeded with chondrocytes were more effective than the hydrogel only group (control). These results are consistent with other studies that have shown that a scaffold inoculated with cell has a better effect on cartilage repair [ 46 , 47 ]. The microfracture of subchondral bone helps in the healing process, although most of the neo-tissue might be fibrocartilage [ 48 , 49 ].…”

“…9 Representative IHC staining after 1 month of implantation, the black dotted lines represent the boundary between implantation and natural cartilage (scale bar: 100 mm): A-C IHC staining of COL II results in cell-seeded group, cell-free group, and control group, respectively; D-F IHC staining of COL IV results in cell-seeded group, cell-free group, and control group, respectively cartilage defects, and hydrogels seeded with chondrocytes were more effective than the hydrogel only group (control). These results are consistent with other studies that have shown that a scaffold inoculated with cell has a better effect on cartilage repair [46,47]. The microfracture of subchondral bone helps in the healing process, although most of the neo-tissue might be fibrocartilage [48,49].…”

In Vitro Cartilage Regeneration with a Three-Dimensional Polyglycolic Acid (PGA) Implant in a Bovine Cartilage Punch Model

“…The present study addresses the long-term performance of a three-dimensional PGA implant in a previously established, standardized in vitro bovine cartilage punch model [29][30][31][32][33][34][35][36][37][38][39][40]. The central findings were that: (i) cartilage/PGA hybrids remained vital with an integer cartilage matrix, limited proteoglycan loss in cartilage ring or cartilage-PGA interface, and diminishing release of proteoglycan into the supernatant; and (ii) both types of PGA (cell-free or cell-loaded) displayed cell immigration/colonization and continuously augmented gene expression for aggrecan and collagen 2.…”

“…However, there are at present no in vitro analyses examining the cellular or molecular mechanisms underlying cartilage repair when using PGA. This study thus aimed at investigating the behavior of the resorbable, three-dimensional PGA implant in a previously established bovine cartilage punch model for the examination of different cartilage implants [29][30][31] and to answer the question whether the experimental results mirror the clinical performance of the PGA. The addressed hypotheses were as follows: (i) the model allows detailed analysis of the underlying in vitro cartilage repair in and around the PGA implant; (ii) PGA supports in vitro cartilage regeneration (through colonization and matrix formation) on the basis of its physicochemical and molecular features.…”

Collagen-Based Electrospun Materials for Tissue Engineering: A Systematic Review

“…Collagen, specifically type I, is a major constituent of many tissues and organs, including skin, bone, tendon, blood vessels, and cardiac tissue. As a result, collagen type I matrices are often used as a surrogate extracellular matrix (ECM) for in vitro tissue engineering and in vivo tissue regeneration or repair [ 1 , 2 , 3 , 4 , 5 ]. Given the fibrous nature of the native ECM, electrospinning, a technique that creates matrices comprised of nanometric or micron-sized fibers, is commonly utilized to generate scaffolds for tissue engineering [ 6 , 7 , 8 , 9 ].…”