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Human adult mesenchymal stem cells hMSC are particularly suitable cells for autologous tissue engineering and cell based therapies They can be isolated from various tissues such as bone marrow adipose tissue dental pulp or umbilical cords Due to their primitive developmental stage umbilical cord derived hMSC are assumed to have a higher proliferation and differentiation capacity than hMSC from adult tissues We isolated hMSC from bone marrow BM and umbilical cords UC and compared the cells regarding their surface epitopes proliferation and differentiation capacity Flow cytometry of specific surface epitopes showed that both BM MSC and UC MSC display the characteristic MSC phenotype Cells from both sources were readily differentiated into adipocytes osteoblasts and chondrocytes according to standard protocols Interestingly only UC MSC spontaneously formed three dimensional aggregates when cultured under post confluent conditions The cells of these aggregates were viable and spontaneously differentiated into several specialized cell types akin to the well known differentiation of embryoid bodies Besides UC MSC expressed the pluripotency associated gene NANOG as well as genes characteristic for the mesodermal and ectodermal fate Thus UC MSC resemble BM MSC but additionally show a spontaneous embryoid body like aggregation and differentiation in vitro These results indicate that UC MSC are less restricted than BM MSC and may thus extend the limits of BM MSC based therapies nbsp

Polyetherketoneketone (PEKK) a high performance thermoplastic polymer that is FDA-approved for cranio- and maxillo-facial as well as spineal surgery. We studied the viability, growth and osteogenic differentiation of bone marrow-derived human and sheep mesenchymal stem cells (MSC) in combination with a 3D scaffold made of PEKK using different cell-based assays. To investigate if autologous MSC, either undifferentiated or osteogenically pre-differentiated, augmented bone formation after implantation, we implanted cell-seeded 3D PEKK scaffolds into calvarial defects in sheep for 12 weeks. The volume and quality of newly formed bone were investigated using micro-computer tomography (micro-CT) and histological stainings. Our results show that the 3D PEKK scaffolds were cyto- and bio-compatible. They allowed for adherence, growth and osteogenic differentiation of human and ovine MSC. However, bone healing seemed unaffected by whether the scaffolds were seeded with MSC. Considerable amounts of newly formed bone were found in all PEKK treated groups, but a fibrous capsule was formed around the implants regardless of cell seeding with MSC. European Association for Cranio-Maxillo-Facial Surgery.