| Craniosynostosis is a disorder characterized by premature fusion of cranial sutures. Treatment of prematurely fused sutures typically involves a series of invasive surgical procedures beginning in infancy. In many cases, surgical sites show rapid resynostosis. This re-fusion requires additional surgical procedures which increase the patient's risk of complications. It is increasingly clear that surgery cannot offer a "cure" for craniosynostosis but only a symptomatic improvement.;Quantifying gene expression patterns in cranial sutures is essential for the design of targeted adjunct therapies for craniosynostosis. Using real time RT-PCR in a rodent model of cranial suture biology, expression profiles of several growth factor ligands and receptors were quantitatively characterized.;Administration of cytokines or genes that correct the underlying pathological process may arrest the ossification process. Exogenous application of transforming growth factor-beta3 (Tgf-beta3) cytokine has been shown to inhibit suture fusion. However, use of cytokines as localized therapeutic agents is limited by the lack of a satisfactory delivery system.;Release kinetics and bioactivity of a simplified cytokine/collagen gel system designed to achieve extended, local delivery of bioactive cytokines at sites of premature cranial suture fusion were investigated.;Delivery of cytokines is limited by short half-life, degradation of the proteins during incorporation or following the release from the vehicle by moisture, temperature, or change in chemical environment. Gene transfer can avoid some of these limitations. Therefore, suitability of a dense collagen gel as a vehicle for sustained delivery of non-viral plasmid DNA to sutural tissues was investigated. Structural integrity, bioactivity and transfectivity of released plasmids were established in rat osteoblast and calvarial organ cultures. Data revealed collagen gel can provide sustained release of plasmid DNA. The plasmid DNA retained its transfectivity as demonstrated by the prolonged osteoblast transfection and elevated growth factor production. The ability to rescue cranial suture fusion by released Tgf-beta3 plasmid was tested in vitro and in vivo. Data from in vitro studies demonstrated that Tgf-beta3 plasmid treated group was found to have 77% to 85% less bony bridging than collagen control and untreated groups. Mean percent bridging of the Tgf-beta3 plasmid treated group was 3.59 +/- 3.21 (mean +/- S.D). Similarly in animals treated with Tgf-beta3 plasmid, there was a significant reduction in suture fusion in the middle region of the posterior frontal sutures when compared to control groups. In this region Tgf-beta3 plasmid treated group was found to have 70% to75% less bony bridging than control groups. These histomorphometric evaluations of suture fusion were validated by micro CT imaging. (Abstract shortened by UMI.)... |
