Phenolated alginate hydrogel induced osteogenic properties of mesenchymal stem cells via Wnt signaling pathway.

Osteogenic properties of phenolated alginate (1.2 %) hydrogel containing collagen (0.5 %)/nano-hydroxyapatite (1 %) were studied on human mesenchymal stem cells in vitro. The phenolation rate and physical properties of the hydrogel were assessed using nuclear magnetic resonance (NMR), Fourier-transform infrared spectroscopy (FTIR), Scanning electron microscope (SEM), swelling ratio, gelation time, mechanical assay, and degradation rate. The viability of encapsulated cells was monitored on days 7, 14, and 21 using an MTT assay. Osteoblast differentiation was studied using western blotting, and real-time PCR. Using PCR array analysis, the role of the Wnt signaling pathway was also investigated. Data showed that the combination of alginate/collagen/nanohydroxyapatite yielded proper mechanical features. The addition of nanohydroxyapatite, and collagen reduced degradation, swelling rate coincided with increased stiffness. Elasticity and pore size were also diminished. NMR and FTIR revealed suitable incorporation of collagen and nanohydroxyapatite in the structure of alginate. Real-time PCR analysis and western blotting indicated the expression of osteoblast-related genes such as Runx2 and osteocalcin. PCR array revealed the induction of numerous genes related to Wnt signaling pathways during the maturation of human stem cells toward osteoblast-like cells. In vivo data indicated that transplantation of phenolated alginate/collagen/nanohydroxyapatite hydrogel led to enhanced de novo bone formation in rats with critical-sized calvarial defects. Phenolated alginate hydrogel can promote the osteogenic capacity of human amniotic membrane mesenchymal stem cells in the presence of nanohydroxyapatite and collagen via engaging the Wnt signaling pathway.

Critical elements in tissue engineering of craniofacial malformations.

Abnormal craniofacial bone fusion can lead to the generation of several congenital malformations such as cleft palate, craniosynostosis and craniofacial skeletal hypoplasia, which physically and mentally affect patients. Conventional approaches for the treatment of craniofacial malformations such as the transplantation of autologous bone grafts are not completely efficient and usually, patients suffer from various complications. In line with these statements, the advent of novel therapeutic approaches in human medicine is mandatory. Regarding the extent, size and severity of the bone malformation, supplementation and release of oxygen molecules into the affected sites are critical issues for successful osteogenesis. Here, tissue engineering modalities associated with oxygen supplementation and novel approaches associated with hydrogel synthesis were highlighted in terms of craniofacial malformations.

Craniofacial anomalies are a group of conditions that can affect a person's head and facial tissue, mostly bones. These abnormalities can be categorized from mild to severe and commonly include the separation in the lip and the palate (cleft palate), the early joining of the baby's skull bone (craniosynostosis) and problems with the lower jawbone (mandibular defects). Several surgical methods are available to treat these abnormalities, which are invasive and have many disadvantages. In this review, we discuss new treatments in regenerative medicine as well as the importance factors of such as oxygen delivery in these methods. The provision of oxygen plays a key role in the growth of new blood vessels, cellular growth and bone tissue reconstruction.