Generation of a scaffold free cartilage-like implant from a small amount of starting material.
BACKGROUND
An autologous cellular based treatment of a traumatic cartilage injury requires a procedure whereby a biopsy of healthy cartilage is removed from the patient and the cells isolated and expanded by monolayer passage. This increases the cell number to required levels but also leads to a de-differentiation of the cells. We aim to produce a scaffold-free, de-novo implant from a biopsy of cartilage.


METHODS
Bovine chondrocytes were isolated from a small biopsy and expanded. The chondrocytic phenotype of the monolayer expanded cells was recovered during a period of culture in alginate and the effect of factors such as IGF1, TFGbeta1 and dexamethasone was investigated.


RESULTS
During the alginate culture period a pre-treatment with IGF1 and dexamethasone was shown to have little effect. IGF1 however increased the glycosaminoglycan/DNA (GAG/DNA) content on day 14 to 84.95+/-5 ng/ng compared with 37.3+/-1.8 ng/ng in the controls (P<0.001). 35S labeling demonstrated an increased GAG synthesis in the presence of IGF1 (P<0.001). IGF1 also induced a increase of DNA content 1383+/-314 ng/bead compared to 512+/-19 ng/bead in the controls (P<0.001). The cells were released from the alginate and cultured in a silicon mould for a further 14 days to obtain a three dimensional implant. Releasing the cells from the alginate and casting in a mould produced an implant of defined shape which contained no foreign material. After 31 days of culture the implants contained 152.4+/-13.14 ng/ng GAG/DNA and 42.93+/-10.23 ng/ng collagen II.


CONCLUSIONS
We believe alginate released chondrocytes provide a real alternative to artificial scaffolds.
Stoddart
M J
MJ
Laboratory for Experimental Cartilage Research, Centre for Rheumatology and Bone Disease, Klinik Im Park, Zürich, Switzerland.
Ettinger
L
L
Häuselmann
H J
HJ
D000464:Alginates / Q000378:metabolism / Q000494:pharmacology; D000818:Animals; D002356:Cartilage / Q000378:metabolism* / Q000502:physiology; D002417:Cattle; D002452:Cell Count; D018929:Cell Culture Techniques; D002478:Cells, Cultured; D019902:Chondrocytes / Q000166:cytology* / Q000187:drug effects; D020723:Glucuronic Acid / Q000378:metabolism / Q000494:pharmacology; D006603:Hexuronic Acids / Q000378:metabolism / Q000494:pharmacology; D007150:Immunohistochemistry; D008863:Microspheres; D019736:Prostheses and Implants; D012825:Silicon / Q000737:chemistry; D013997:Time Factors; D023822:Tissue Engineering
D000464:Alginates; D006603:Hexuronic Acids; D020723:Glucuronic Acid; D012825:Silicon