Influence of temporary chondroitinase ABC-induced glycosaminoglycan suppression on maturation of tissue-engineered cartilage.
OBJECTIVE
A fundamental challenge of cartilage tissue engineering has been the inability to promote collagen synthesis up to native levels. In contrast, recent protocols have demonstrated that glycosaminoglycans (GAG) can be synthesized to native levels in 4-6 weeks of in vitro culture. We hypothesize that rapid GAG synthesis may be an impediment to collagen synthesis, possibly by altering transport pathways of nutrients or synthesis products. In this study, this hypothesis is tested by inducing enzymatic GAG loss in the early culture period of cartilage tissue constructs, and monitoring collagen content at various time points after cessation of enzymatic treatment.


METHODS
In Study 1, to induce breakdown of proteoglycans, chondroitinase ABC (CABC, 0.002U/mL) was continuously added into the culture media for the initial 4 weeks of culture or for 2 weeks starting on day 14 of culture. In Study 2, multiple transient CABC treatments (0.15U/mL, for 2 days) were applied to the matured tissue-engineered constructs.


RESULTS
Continuous and transient CABC treatments significantly increased the collagen concentration of the constructs, improving their tensile properties. The GAG content of the treated constructs recovered quickly to the pretreatment level after 2-3 weeks.


CONCLUSIONS
This study demonstrates that tissue-engineered cartilage constructs with improved tensile properties can be achieved by temporarily suppressing the GAG content enzymatically.
Bian
Liming
L
Cellular Engineering Laboratory, Department of Biomedical Engineering, Columbia University, New York, New York, USA.
Crivello
Keith M
KM
Ng
Kenneth W
KW
Xu
Duo
D
Williams
David Y
DY
Ateshian
Gerard A
GA
Hung
Clark T
CT
D000818:Animals; D002356:Cartilage / Q000166:cytology* / Q000201:enzymology*; D002417:Cattle; D002454:Cell Differentiation; D019765:Chondroitin ABC Lyase / Q000378:metabolism*; D006025:Glycosaminoglycans / Q000378:metabolism*; D006026:Glycoside Hydrolases / Q000378:metabolism; D010619:Phenazines / Q000378:metabolism; D013194:Staining and Labeling; D013718:Tensile Strength; D013997:Time Factors; D023822:Tissue Engineering
D006025:Glycosaminoglycans; D010619:Phenazines; D006026:Glycoside Hydrolases; C019624:agarase; D019765:Chondroitin ABC Lyase; C009195:safranine T