An Intact Periosteum is Required for Recombinant Human Jagged1 Guided Bone Regeneration in Calvaria Critical-size Defect Healing.

ABSTRACT

The need to promote calvaria bone healing as a consequence of injury or craniotomy is a major clinical issue. Previous reports tested recombinant human Jagged1 (rhJagged1) treatment for critical-size calvaria defects in the absence of periosteum, and this resulted in significant new bone formation. As the periosteum contributes to healing by serving as a source of progenitor cells, the present study aimed to examine whether significantly more bone is formed when the periosteum is intact for using rhJagged1 to treat critical-size parietal bone defects in mice. Fifteen healthy adult mice, 34 to 65 weeks of age, 26.9 to 48.2 g, were divided into different groups that compared the critical-size defects treated with either phosphate-buffered saline or rhJagged1 protein in either the presence or absence of periosteum. The results indicated that more bone was formed in the presence of periosteum when rhJagged1 is delivered [35% bone volume per tissue volume (BV/TV); P = 0.02] relative to nonperiosteum. Recombinant human Jagged1 protein delivered in the absence of periosteum had the next most new bone formed (25% BV/TV). Defects with phosphate-buffered saline delivered in the absence or presence of periosteum had the least new bone formed (15% and 18% BV/TV, respectively; P = 0.48). The results also show that rhJagged1 does not form ectopic or hypertrophic bone. The usage of rhJagged1 to treat critical-size defects in calvaria is promising clinically, but to maximize clinical efficacy it will require that the periosteum be intact on the noninjured portions of calvaria.