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Acute Osteoclast Activity following Subchondral Drilling Is Promoted by Chitosan and Associated with Improved Cartilage Repair Tissue Integration.

Chen G, Sun J, Lascau-Coman V, Chevrier A, Marchand C, Hoemann CD - Cartilage (2011)

Bottom Line: Chitosan was retained at the top of the drill holes at 1 week as extracellular particles became internalized by granulation tissue cells at 2 weeks and was completely cleared by 8 weeks.Osteoclasts burst-accumulated at microdrill hole edges at 1 week, in new woven bone at the base of the drill holes at 2 weeks, and below endochondral cartilage repair at 8 weeks.Osteoclasts are cellular mediators of marrow-derived cartilage repair integration.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemical Engineering, Ecole Polytechnique, Montreal, Quebec, Canada.

ABSTRACT

Objective: Cartilage-bone integration is an important functional end point of cartilage repair therapy, but little is known about how to promote integration. We tested the hypothesis that chitosan-stabilized blood clot implant elicits osteoclasts to drilled cartilage defects and promotes repair and cartilage-bone integration.

Design: Bilateral trochlear defects in 15 skeletally mature rabbit knees were microdrilled and then treated with chitosan-glycerol phosphate (GP)/blood implant with fluorescent chitosan tracer and thrombin to accelerate in situ solidification or with thrombin alone. Chitosan clearance, osteoclast density, and osteochondral repair were evaluated at 1, 2, and 8 weeks at the outside, edge, and through the proximal microdrill holes.

Results: Chitosan was retained at the top of the drill holes at 1 week as extracellular particles became internalized by granulation tissue cells at 2 weeks and was completely cleared by 8 weeks. Osteoclasts burst-accumulated at microdrill hole edges at 1 week, in new woven bone at the base of the drill holes at 2 weeks, and below endochondral cartilage repair at 8 weeks. Implants elicited 2-fold more osteoclasts relative to controls (P < 0.001), a more complete drill hole bone repair, and improved cartilage-bone integration and histological tissue quality. Treated and control 8-week cartilage repair tissues contained 85% collagen type II. After 8 weeks of repair, subchondral osteoclast density correlated positively with bone-cartilage repair tissue integration (P < 0.0005).

Conclusions: Chitosan-GP/blood implant amplified the acute influx of subchondral osteoclasts through indirect mechanisms, leading to significantly improved repair and cartilage-bone integration without inducing net bone resorption. Osteoclasts are cellular mediators of marrow-derived cartilage repair integration.

No MeSH data available.


Related in: MedlinePlus

Subchondral TRAP+ osteoclast density at 8 weeks postoperatively correlated strongly with percentage of integrated repair (7 treated and 7 untreated defects, 3 sections per defect).
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fig9-1947603510381096: Subchondral TRAP+ osteoclast density at 8 weeks postoperatively correlated strongly with percentage of integrated repair (7 treated and 7 untreated defects, 3 sections per defect).


Acute Osteoclast Activity following Subchondral Drilling Is Promoted by Chitosan and Associated with Improved Cartilage Repair Tissue Integration.

Chen G, Sun J, Lascau-Coman V, Chevrier A, Marchand C, Hoemann CD - Cartilage (2011)

Subchondral TRAP+ osteoclast density at 8 weeks postoperatively correlated strongly with percentage of integrated repair (7 treated and 7 untreated defects, 3 sections per defect).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4300782&req=5

fig9-1947603510381096: Subchondral TRAP+ osteoclast density at 8 weeks postoperatively correlated strongly with percentage of integrated repair (7 treated and 7 untreated defects, 3 sections per defect).
Bottom Line: Chitosan was retained at the top of the drill holes at 1 week as extracellular particles became internalized by granulation tissue cells at 2 weeks and was completely cleared by 8 weeks.Osteoclasts burst-accumulated at microdrill hole edges at 1 week, in new woven bone at the base of the drill holes at 2 weeks, and below endochondral cartilage repair at 8 weeks.Osteoclasts are cellular mediators of marrow-derived cartilage repair integration.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemical Engineering, Ecole Polytechnique, Montreal, Quebec, Canada.

ABSTRACT

Objective: Cartilage-bone integration is an important functional end point of cartilage repair therapy, but little is known about how to promote integration. We tested the hypothesis that chitosan-stabilized blood clot implant elicits osteoclasts to drilled cartilage defects and promotes repair and cartilage-bone integration.

Design: Bilateral trochlear defects in 15 skeletally mature rabbit knees were microdrilled and then treated with chitosan-glycerol phosphate (GP)/blood implant with fluorescent chitosan tracer and thrombin to accelerate in situ solidification or with thrombin alone. Chitosan clearance, osteoclast density, and osteochondral repair were evaluated at 1, 2, and 8 weeks at the outside, edge, and through the proximal microdrill holes.

Results: Chitosan was retained at the top of the drill holes at 1 week as extracellular particles became internalized by granulation tissue cells at 2 weeks and was completely cleared by 8 weeks. Osteoclasts burst-accumulated at microdrill hole edges at 1 week, in new woven bone at the base of the drill holes at 2 weeks, and below endochondral cartilage repair at 8 weeks. Implants elicited 2-fold more osteoclasts relative to controls (P < 0.001), a more complete drill hole bone repair, and improved cartilage-bone integration and histological tissue quality. Treated and control 8-week cartilage repair tissues contained 85% collagen type II. After 8 weeks of repair, subchondral osteoclast density correlated positively with bone-cartilage repair tissue integration (P < 0.0005).

Conclusions: Chitosan-GP/blood implant amplified the acute influx of subchondral osteoclasts through indirect mechanisms, leading to significantly improved repair and cartilage-bone integration without inducing net bone resorption. Osteoclasts are cellular mediators of marrow-derived cartilage repair integration.

No MeSH data available.


Related in: MedlinePlus