|  |  |  | | | | | TERMSC | | | | | | | | | | | | | | | | | | | Laser-based direct-write techniques for cell printing. Biofabrication. 2010 Jul 12;2(3):032001 Authors: Schiele NR, Corr DT, Huang Y, Raof NA, Xie Y, Chrisey DB Fabrication of cellular constructs with spatial control of cell location (+/-5 microm) is essential to the advancement of a wide range of applications including tissue engineering, stem cell and cancer research. Precise cell placement, especially of multiple cell types in co- or multi-cultures and in three dimensions, can enable research possibilities otherwise impossible, such as the cell-by-cell assembly of complex cellular constructs. Laser-based direct writing, a printing technique first utilized in electronics applications, has been adapted to transfer living cells and other biological materials (e.g., enzymes, proteins and bioceramics). Many different cell types have been printed using laser-based direct writing, and this technique offers significant improvements when compared to conventional cell patterning techniques. The predominance of work to date has not been in application of the technique, but rather focused on demonstrating the ability of direct writing to pattern living cells, in a spatially precise manner, while maintaining cellular viability. This paper reviews laser-based additive direct-write techniques for cell printing, and the various cell types successfully laser direct-written that have applications in tissue engineering, stem cell and cancer research are highlighted. A particular focus is paid to process dynamics modeling and process-induced cell injury during laser-based cell direct writing. PMID: 20814088 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | In vitro Evaluation of Acellular Dermal Matrix as a Three-Dimensional Scaffold for Gingival Fibroblasts Seeding. J Periodontol. 2010 Sep 2; Authors: Maia LP, Novaes AB, Souza SL, Grisi MF, Taba M, Palioto DB Background: Tissue engineering principles could improve acellular dermal matrix (ADM) incorporation. The aim of this study was to verify if ADM is a suitable three-dimensional matrix for gingival fibroblasts and cancerous cells ingrowth; and also, if cultured medium conditioned in ADM affect cellular behavior. Methods: Canine gingival fibroblasts (CGF), human gingival fibroblasts (HGF) and murine melanoma cell line (B16F10) were seeded on AMD for up to 14 days. The following parameters were assessed: morphology and distribution of CGF, HGF and B16F10; CGF and HGF viability and the effect of ADM conditioned medium (CM) on CGF viability. Results: Epifluorescence revealed that CGF were unevenly distributed on ADM surface, showing no increase in cell number over the periods; HGF formed a monolayer on ADM surface, in a higher number at 14 days (p<0.05); B16F10 exhibited an increase in cell number within 7 days (p<0.05), and were mainly arranged in cell aggregates on ADM, forming a continuous layer at 14 days. A higher percentage of cells on ADM surface (p <0.05) compared to inside was observed for all cell types. MTT values indicated higher cell viability in samples cultured with HGF compared to CGF (p=0.024). A significantly lower cell viability for CGF grown in CM compared to cells grown in non conditioned medium was observed at 48 and 72 h (p <0.05). Conclusion: ADM is not suitable as a 3D matrix for gingival fibroblasts ingrowth. Gingival fibroblasts and highly proliferative cells as B16F10 can be only superficially located on ADM and CGF are negatively affected by culture medium conditioned in ADM, reducing its viability. PMID: 20812778 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Tissue engineering in plastic surgery: a review. Plast Reconstr Surg. 2010 Sep;126(3):858-68 Authors: Wong VW, Rustad KC, Longaker MT, Gurtner GC Novel tissue- and organ-engineering strategies are needed to address the growing need for replacement biological parts. Collective progress in stem cell technology, biomaterials, engineering, and molecular medicine has advanced the state of regenerative medicine, yet many hurdles to clinical translation remain. Plastic surgeons are in an ideal position to capitalize on emerging technologies and will be at the forefront of transitioning basic science research into the clinical reconstructive arena. This review highlights fundamental principles of bioengineering, recent progress in tissue-specific engineering, and future directions for this exciting and rapidly evolving area of medicine. PMID: 20811219 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Depot-specific variation in the osteogenic and adipogenic potential of human adipose-derived stromal cells. Plast Reconstr Surg. 2010 Sep;126(3):822-34 Authors: Levi B, James AW, Glotzbach JP, Wan DC, Commons GW, Longaker MT BACKGROUND:: Adipose-derived stromal cells hold promise for use in tissue regeneration. However, multiple facets of their biology remain unclear. The authors examined the variations in osteogenesis and adipogenesis in adipose-derived stromal cells between subcutaneous fat depots and potential molecular causes. METHODS:: Adipose-derived stromal cells were isolated from human patients from subcutaneous fat depots, including arm, flank, thigh, and abdomen (n = 5 patients). Osteogenic and adipogenic differentiation was performed (alkaline phosphatase, alizarin red, and oil red O staining, and quantitative real-time polymerase chain reaction). Co-cultures were established to assess the paracrine effect of human adipose-derived stromal cells on mouse osteoblasts. Finally, HOX gene expression was analyzed by quantitative real-time polymerase chain reaction. RESULTS:: Subcutaneous fat depots retain markedly different osteogenic and adipogenic potentials. Osteogenesis was most robust in adipose-derived stromal cells from the flank and thigh, as compared with those from the arm and abdomen (p < 0.05 by all markers examined). This was accompanied by elevations of BMP4 and BMPR1B (p < 0.05 by all markers examined). The osteogenic advantage of cells from the flank and thigh was again observed when analyzing the paracrine effects of these cells. Conversely, those cells isolated from the flank had a lesser ability to undergo adipogenic differentiation. Adipose-associated HOX genes were less expressed in flank-derived adipose-derived stromal cells. CONCLUSIONS:: Variations exist between fat depots in terms of adipose-derived stromal cell osteogenic and adipogenic differentiation. Differences in HOX expression and bone morphogenetic protein signaling may underlie these observations. This study indicates that the choice of fat depot derivation of adipose-derived stromal cells may be an important one for future efforts in tissue engineering. PMID: 20811215 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Deconstructing pancreas development to reconstruct human islets from pluripotent stem cells. Cell Stem Cell. 2010 Apr 2;6(4):300-8 Authors: McKnight KD, Wang P, Kim SK There is considerable excitement about harnessing the potential of human stem cells to replace pancreatic islets that are destroyed in type 1 diabetes mellitus. However, our current understanding of the mechanisms underlying pancreas and islet ontogeny has come largely from the powerful genetic, developmental, and embryological approaches available in nonhuman organisms. Successful islet reconstruction from human pluripotent cells will require greater attention to "deconstructing" human pancreas and islet developmental biology and consistent application of conditional genetics, lineage tracing, and cell purification to stem cell biology. PMID: 20362535 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Spatial regulation of human mesenchymal stem cell differentiation in engineered osteochondral constructs: effects of pre-differentiation, soluble factors and medium perfusion. Osteoarthritis Cartilage. 2010 May;18(5):714-23 Authors: Grayson WL, Bhumiratana S, Grace Chao PH, Hung CT, Vunjak-Novakovic G OBJECTIVE: The objective of the study was to investigate the combined effects of three sets of regulatory factors: cell pre-differentiation, soluble factors and medium perfusion on spatial control of human mesenchymal stem cell (hMSC) differentiation into cells forming the cartilaginous and bone regions in engineered osteochondral constructs. DESIGN: Bone-marrow derived hMSCs were expanded in their undifferentiated state (UD) or pre-differentiated (PD) in monolayer culture, seeded into biphasic constructs by interfacing agarose gels and bone scaffolds and cultured for 5 weeks either statically (S) or in a bioreactor (BR) with perfusion of medium through the bone region. Each culture system was operated with medium containing either chondrogenic supplements (C) or a cocktail (Ck) of chondrogenic and osteogenic supplements. RESULTS: The formation of engineered cartilage in the gel region was most enhanced by using undifferentiated cells and chondrogenic medium, whereas the cartilaginous properties were negatively affected by using pre-differentiated cells or the combination of perfusion and cocktail medium. The formation of engineered bone in the porous scaffold region was most enhanced by using pre-differentiated cells, perfusion and cocktail medium. Perfusion also enhanced the integration of bone and cartilage regions. CONCLUSIONS: (1) Pre-differentiation of hMSCs before seeding on scaffold was beneficial for bone but not for cartilage formation. (2) The combination of medium perfusion and cocktail medium inhibited chondrogenesis of hMSCs. (3) Perfusion improved the cell and matrix distribution in the bone region and augmented the integration at the bone-cartilage interface. (4) Osteochondral grafts can be engineered by differentially regulating the culture conditions in the two regions of the scaffold seeded with hMSCs (hydrogel for cartilage, perfused porous scaffold for bone). PMID: 20175974 [PubMed - indexed for MEDLINE] | | | | | | | | | |  | |  | |  |
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