Tissue interactions between craniosynostotic dura mater and bone.

BACKGROUND: Cells within the dura mater have been implicated in the determination of suture patency and fusion. Craniosynostosis (CS), the premature fusion of 1 or more of the cranial sutures, could result from abnormal control over the differentiation of osteoprogenitor cells from the dura mater. This study tested whether dura mater cells derived from rabbits with congenital CS were different from cells derived from normal rabbits and investigated the effects that CS dura mater had on osteogenic differentiation in vitro and in vivo.
METHODS: Cells were derived from the dura mater from wild-type rabbits (WT; n = 23) or CS rabbits (n = 16). Cells were stimulated with bone morphogenetic protein 4, and alkaline phosphatase (ALP) expression and cell proliferation were assessed. Dura mater-derived cells were also cocultured with primary rabbit bone-derived cells, and ALP was assessed. Finally, interactions between the dura mater and overlying tissues were manipulated in vivo.
RESULTS: Craniosynostotic dura mater-derived cells proliferated faster than did WT cells but were not more ALP positive. Coculture experiments showed that CS dura mater cells induced increased ALP activity in CS bone-derived cells, but not in WT bone-derived cells. In vivo experiments showed that a physical barrier successfully inhibited dura mater-derived osteogenesis.
CONCLUSIONS: Coculture of CS bone- and CS dura mater-derived cells evoked an abnormal phenotype in vitro. Covering the CS dura mater led to decreased bone formation in vivo. Further investigations will focus on the signaling molecules involved in the communication between these 2 CS tissue types in vitro and in vivo.