Bone tissue engineering in the growing calvarium using dipyridamole-coated 3D printed bioceramic scaffolds: Construct optimization and effects to cranial suture patency
Maliha SG, Lopez CD, Coelho PG, Witek L, Cox M, Meskin A, Rusi S, Torroni A, Cronstein BN, Flores RL
A clinical need exists for the development of bone tissue engineering approaches to address craniofacial bone defects in pediatric patients without affecting the patency of craniofacial sutures. However, pre-clinical development of bone tissue engineering strategies generally involves skeletally mature animal models that may not suitably reflect the skeletal anatomy and growth of pediatric patients. A recent study by Maliha et al. investigated calvarial defect healing upon implantation of 3D-printed bioceramic scaffolds delivering the osteogenic agent dipyridamole in a 5-week-old rabbit model. The 3D-printed scaffolds comprised beta-tricalcium phosphate coated with collagen soaked in different concentrations of dipyridamole. Each scaffold presented 3 different pore sizes in distinct regions to facilitate investigation of the effect of pore size on bone formation. The authors reported significantly greater bone formation in defects treated with scaffolds relative to empty defects as marked by micro-computed tomography and histological analysis after 8 weeks. The authors also found the greatest bone growth and least residual scaffold presence in the scaffolds with the largest pores (500 microns) coated with 1,000 micro-molar dipyridamole. Interestingly, sutural patency was maintained in all groups, with no incidences of ectopic bone formation observed. Overall, the article suggests that dipyridamole-laden 3D-printed bioceramic scaffolds may promote craniofacial bone regeneration in pediatric applications without adversely affecting sutural patency, but the authors underscore that additional investigation is warranted prior to clinical translation of the approach.