Developing a tissue engineering strategy for cleft palate repair

The most common craniofacial birth defect is cleft defect with an incidence of 1.7:1000 live births. The current treatments involve many steps of surgical procedures and cause morbidity at the donor site when harvesting bone for filling the gap defect. It may be possible to treat cleft palate defects by tissue engineering strategies using osteoprogenitor cells on a biodegradable distensible electrospun scaffolds to form the hard palate. The aims of this project are to select the suitable cell sources, materials, chemical supplementation, and mechanical conditions to enhance matrix mineralization for repairing the bone part of a cleft palate. Human jaw periosteal cells (HJPs), human mesenchymal stem cell derived from bone marrow (hBMSCs), and human embryonic stem cell mesenchymal progenitor (hESMPs) used in this project showed osteogenic potential by depositing calcium deposition on both monolayer and 3D constructs with the requirement of Dex in the culture media. Electrospun poly(?-caprolactone) scaffolds (PCL) are a suitable temporary extracellular matrix for bone tissue engineering. Vascular endothelial growth factor (VEGF) is an important protein for new blood vessel formation. The VEGF secretion was reduced by Dex supplemented culture media in 3D culture, whereas, it was delayed in the monolayer culture. All cell types responded to oscillatory fluid flow (OFF) by using a standard see-saw rocker to stimulate osteogenic differentiation. The cells were more sensitive to OFF when they were supplemented with Dex for enhancing calcium deposition both in monolayer culture and 3D culture and the strongest effect was at the top surface of the scaffolds. The composite nano-hydroxyapatite PCL electrospun scaffold can enhance matrix mineralization compared to the standard PCL scaffold, but there were no additional effects of OFF on these scaffolds. A tri-layer PCL scaffold could support and separate two different cell types (human dermal fibroblasts and human osteoprogenitor cells: both hESMPs and hBMSCs) and also allow osteogenic differentiation for 28 days. The novel tri-layer PCL electrospun membrane developed here is a promising scaffold for tissue engineering for cleft palate repair. Tissue engineering strategy could benefit treatment cleft palate treatment compared to the current treatments (autologous bone graft from iliac crest) to promote bone formation at the defect area and allow normal development of facial structure in the future.