Influence of poly(L-lactic acid) nanofibers and BMP-2-containing poly(L-lactic acid) nanofibers on growth and osteogenic differentiation of human mesenchymal stem cells

• Published in: TheScientificWorld 2008-12, Vol.8, p.1269-1279
• Main Authors: Schofer, Markus D, Fuchs-Winkelmann, Susanne, Gräbedünkel, Christian, Wack, Christina, Dersch, Roland, Rudisile, Markus, Wendorff, Joachim H, Greiner, Andreas, Paletta, Jürgen Rj, Boudriot, Ulrich
• Format: Article
• Language: English
• Subjects: Alkaline Phosphatase - metabolism; Bone Morphogenetic Protein 2 - chemistry; Cell Differentiation; Cells, Cultured; Collagen Type I - metabolism; Gene Expression Regulation; Humans; Lactic Acid - chemistry; Mesenchymal Stromal Cells - cytology; Microscopy, Fluorescence; Nanoparticles - chemistry; Osteocalcin - metabolism; Osteogenesis; Polyesters; Polymers - chemistry; Stem Cells - cytology; Tissue Engineering - methods
• ISSN: 1537-744X; 2356-6140; 1537-744X
• DOI: 10.1100/tsw.2008.163

The aim of this study was to characterize synthetic poly-(L-lactic acid) (PLLA) nanofibers concerning their ability to promote growth and osteogenic differentiation of stem cells in vitro, as well as to test their suitability as a carrier system for growth factors. Fiber matrices composed of PLLA or BMP-2-incorporated PLLA were seeded with human mesenchymal stem cells and cultivated over a period of 22 days under growth and osteoinductive conditions, and analyzed during the course of culture, with respect to gene expression of alkaline phosphatase (ALP), osteocalcin (OC), and collagen I (COL-I). Furthermore, COL-I and OC deposition, as well as cell densities and proliferation, were analyzed using fluorescence microscopy. Although the presence of nanofibers diminished the dexamethasone-induced proliferation, there were no differences in cell densities or deposition of either COL-I or OC after 22 days of culture. The gene expression of ALP, OC, and COL-I decreased in the initial phase of cell cultivation on PLLA nanofibers as compared to cover slip control, but normalized during the course of cultivation. The initial down-regulation was not observed when BMP-2 was directly incorporated into PLLA nanofibers by electrospinning, indicating that growth factors like BMP-2 might survive the spinning process in a bioactive form.