Effect of transforming growth factor beta 2 on marrow-infused foam poly(propylene fumarate) tissue-engineered constructs for the repair of critical-size cranial defects in rabbits.
This study investigates the osseointegration of poly(propylene fumarate) (PPF) with beta-tricalcium phosphate (beta-TCP) scaffolds in a critical-size (diameter, 1.6 cm), cranial defect in 4-month-old rabbits (n = 51), killed at 6 or 12 weeks. Two molecular weights of PPF were used to produce bilayer scaffolds with 0.5-mm solid external and 2.0-mm porous internal layers. The porous layer was infused with bone marrow aspirate, with half the animals receiving 0.8 microg of transforming growth factor beta2 (TGF-beta2). No foreign body or inflammatory response was observed externally or on histological examination of explants. Statistical analysis of histological areal and linear measures of new bone formation found significantly more bone at the later sacrifice time, followed by implants receiving TGF-beta2, followed by low molecular weight PPF implants. Approximately 40% of the explants were tested for incorporation strength with a one-point "push-in" test. Because no permanent fixation was used, implant strength (28.37-129.03 N; range, 6.4 to 29.0 lb of resistance) was due entirely to new bone formation. The strongest bone was seen in implants receiving TGF-beta2-infused marrow in animals killed at 12 weeks. These results support the use of PPF as an osteogenic substrate and future research into preoperative fabrication of critical size and supercritical-size cranial prosthetic implants.
Department of Neurological Surgery and Research Institute, University Hospitals of Cleveland, Case Western Reserve University, Cleveland, Ohio 44106, USA. dxd35@cwru.edu
David
D
Dean
Michael S
MS
Wolfe
Yusra
Y
Ahmad
Ali
A
Totonchi
Jeffrey E-K
JE
Chen
John P
JP
Fisher
Malcolm N
MN
Cooke
Clare M
CM
Rimnac
Donald P
DP
Lennon
Arnold I
AI
Caplan
Neal S
NS
Topham
Antonios G
AG
Mikos
D000818:Animals; D001854:Bone Marrow Cells; D018786:Bone Substitutes; D019465:Craniofacial Abnormalities / Q000601:surgery; D005650:Fumarates / Q000138:chemical synthesis; D008855:Microscopy, Electron, Scanning; D011126:Polypropylenes / Q000138:chemical synthesis; D011817:Rabbits; D012886:Skull / Q000002:abnormalities*; D013997:Time Factors; D023822:Tissue Engineering; D016212:Transforming Growth Factor beta / Q000494:pharmacology*; D053781:Transforming Growth Factor beta2
D018786:Bone Substitutes; D005650:Fumarates; D011126:Polypropylenes; D016212:Transforming Growth Factor beta; D053781:Transforming Growth Factor beta2; C097850:poly(propylene fumarate)