Chondrocyte-laden collagen scaffolds for resurfacing extensive articular cartilage defects

Abstract

Chondrocyte-collagen composites were evaluated for resurfacing of large articular defects. Isolated chondrocytes were cultured in expanded collagen scaffolds for 7-10 days to provide a composite containing 3.6 x 10(4) cells/mm3. The graft was transplanted into 15 mm full thickness articular defects in the femoropatellar joint of 12 horses using arthroscopic techniques. Ungrafted defects in the opposite femoropatellar joint served as controls. Synovial fluid, clinical progress and pain responses were evaluated in groups of 6 horses over 4-month and 8-month periods. Following termination, gross, histochemical and histologic evaluations of the repair tissues and synovial membrane were performed. Arthroscopic defect debridement and chondrocyte implantation resulted in minimal post-operative effusion or pain, and synovial fluid constituents were not significantly different in grafted and ungrafted joints. Gross differences in grafted defects were not apparent. Increased chondrocyte numbers and cartilage histochemical staining were evident in the deeper layers of grafted defects, whereas ungrafted defects were almost entirely fibrous tissue. The surface layers of grafted defects were fibrous tissue. There were no synovial fluid cellular responses, synovial membrane histiocytic reaction or subchondral bone infiltrates to suggest immune-related reaction to the allograft cells. Chondrocyte-collagen grafts were arthroscopically implanted and resulted in improved cartilage healing in extensive defects. However, the structural organization of the surface layers was inadequate and suggested poor long-term durability.

Acceleration of cartilage repair by genetically modified chondrocytes over expressing bone morphogenetic protein‐7

“…"fi,S Experimental cartilage defects (see below) were repaired using genetically iiiodified allogenic chondrocytes suspended in autogenous fibrin glue. Autogenous fibrinogen was cryoprecipitated from plasma collected from the horse undergoing experimental cartilage repair [14,32]. Allogenic chondrocytes were harvested from cartilage of the dihtal femur and proximal tibia of donor foals (3-9 months old) at postmortem, and kept frozen in liquid nitrogen until ready for use [14.32].…”

“…the mixture placed in a 30 "C water bath for 5 h. The reaction was stopped with a 9-fold excess by volume of distilled water, then frozen at -80 "C and lyophilized. The lyophilized samples were suspended in sample buffer [14,32], and 10 pg of the CNBr-digested sample was loaded and separated on 12%) SDS-PAGE gels. The gels were fixed, stained with Coomassie Blue R 250 (Fisher Scientific, Ontario, Canada).…”

“…The wet gels were scanned digitally and the intensity of the relevant bands were measured using Metamorph software (Lakewood, OH). The band intensities that represented the peptide bands with major contribution of a type I1 collagen peptide in tlie n~itnerator and type I collagen in the denominator were used to form the ratio: 31 (11) CB 101x2 ( I ) CB 3,5 [14,32]. The proportion of type I1 relative to type I collagen was determined for each ratio using standard curves created from gels run with sequential proportions of CNBr-cleaved peptides of purified type I collagen from equine tendon and type I1 collagen froin equine cartilage [14,32].…”

“…The band intensities that represented the peptide bands with major contribution of a type I1 collagen peptide in tlie n~itnerator and type I collagen in the denominator were used to form the ratio: 31 (11) CB 101x2 ( I ) CB 3,5 [14,32]. The proportion of type I1 relative to type I collagen was determined for each ratio using standard curves created from gels run with sequential proportions of CNBr-cleaved peptides of purified type I collagen from equine tendon and type I1 collagen froin equine cartilage [14,32]. (2003) [573][574][575][576][577][578][579][580][581][582][583] Bioi i i c d~t i i i c r i l iiropc~r I ies Bioinechanical properties of the repair tissue as compared to that of normal appeal-ing cartilage froin the medial trochlear ridge was assessed by confined compression testing of 5 mm diameter samples harvested using a skin biopsy punch and scalpel.…”

“…In humans, rehabilitation guidelines following chondrocyte transplantation include limitation of weight-bearing for up to 6 months, and progression to full activities only after 9 months to 1 year [23]. In horses, significant repair does not occur for at least 4 months after chondrocyte transplantation in an equine cartilage defect model [14,32].…”