Materials For Regenerative Medicine Research Articles

Observing cell response to biomaterials

The use of temporary, functional porous materials in regenerative medicine has great potential to reduce the need for replacement of damaged tissue. Several new nanostructured macroporous materials are being designed to mimic tissue structure and properties, and to stimulate new tissue growth while degrading in the body. However, cell response studies must be carried out in vitro before in vivo tests and clinical trials can be undertaken. Here, some techniques for characterizing these materials and for investigating their cell response are discussed. The use of conventional two-dimensional cell culture assays is not always possible on bulk porous materials.

Editorial: A forecast of the future for biomaterials

In September 2005 we held a symposium, at Imperial College London, celebrating the 44 year career and achievements of Professor Hench in the field of bioactive materials. The event was supported by the Department of Materials and the Tissue Engineering and Regenerative Medicine Centre at Imperial College London. The symposium was a two days event including invited keynote lectures and submitted talks from many international leaders in the field who have worked with Professor Hench over the years. There were also many posters from students and researchers from around the UK. The aim of the symposium was to bring together leaders in the field of biomaterials and bioceramics to review the past successes of the field and to look to the future of biomaterials research in general. This special issue features papers based on the topics discussed at the symposium. Professor Hench’s seminal work was his discovery of Bioglass©R with colleagues at the University of Florida. His work then moved towards materials for regenerative medicine, which brought him to Imperial College London. In this issue, Professor Bill Bonfield (University of Cambridge) reviews Professor Hench’s life and how the discovery launched the field of bioactive ceramics, while Professor Hench himself reviews the history of Bioglass©R. Recent bioactive glass research, including the development of tissue engineering scaffolds and bioactive sol-gel derived glasses

American Association of Anatomists meeting on regenerative medicine

Several years ago, the American Association of Anatomists (AAA) launched an innovative mini-meeting format as part of their annual meeting. The AAA continued this tradition by sponsoring a 2-day mini-symposium as a part of its meeting at FASEB Experimental Biology, 2006 in San Francisco, CA, USA. This year, the mini-symposium was focused on the promising and rapidly developing field of ‘regenerative medicine’. The mini-symposium on ‘regenerative medicine’ included four separate but thematically integrated sessions: stem cells for regenerative medicine; biomimetic matrices for regenerative medicine; endothelial–mesenchymal transformation in cardiovascular regenerative medicine; and tissue engineering technologies for regenerative medicine. The goal of these sessions was to identify progress and highlight new trends and directions in the evolving field of regenerative medicine. It was an exciting 2-day mini-symposium that reviewed the differential potential of embryonic and adult stem cells, their role in tissue turnover and possible applications in tissue regeneration; identified important evolving basic science issues, such as the role of endothelial–mesenchymal transformation and stem cell recruitment in cardiovascular regenerative medicine; and, finally, clearly demonstrated how understanding basic scientific principles can be translated into novel cell therapeutics and tissue engineering modalities. The workshop also demonstrated the multidisciplinary (speakers included stem cell and developmental biologists, chemical engineers, tissue engineers, biophysicists, mathematicians and surgeons) and international (speakers represented US, Japan, Canada, Switzerland and Korea) character of ongoing efforts in the area of regenerative medicine and stem cell biology, impressive progress in this field, and confirmed the strong potential for clinical translation of emerging regenerative medicine technologies.

Nano-Scaled Hydroxyapatite/Silk Fibroin Composites as Mesenchymal Cell Culture Scaffolds

The objective of this study was to evaluate cell adhesion and proliferation on the hydroxyapatite (HAp)-coated silk fibroin (SF) fabric. Nano-scaled sintered HAp particles were covalently coated on SF chemically modified by graft polymerization. After the fabrication of the HAp/SF composite, mesenchymal cells (MCs) derived from EGFP-expressing transgenic rat bone marrow were seeded on the composite and cultured for 10 days. Fluorescence and scanning electron microscopy (SEM) revealed that the cells adhered and actively proliferated on the composites comparable to those on tissue culture polystyrene (TCPS) dishes. The results suggest that the composites are suitable for mesenchymal cell culture scaffolds and useful materials for regenerative medicine.

Regulation of neural markers nestin and GFAP expression by cultivated bone marrow stromal cells.

Bone marrow stromal cells can differentiate into many types of mesenchymal cells, i.e. osteocyte, chondrocyte and adipocyte, but can also differentiate into non-mesenchymal cells, i.e. neural cells under appropriate in vivo experimental conditions (Kopen et al., 1999; Brazelton et al., 2000; Mezey et al., 2000). This neural phenotypic plasticity allows us to consider the utilization of mesenchymal stem cells as cellular material in regenerative medicine. In this study, we demonstrate that cultured adult rat stromal cells can express nestin, an intermediate filament protein predominantly expressed by neural stem cells. Two factors contribute to the regulation of nestin expression by rat stromal cells: serum in the culture medium inhibits nestin expression and a threshold number of passages must be reached below which nestin expression does not occur. Only nestin-positive rat stromal cells are able to form spheres when they are placed in the culture conditions used for neural stem cells. Likewise, only nestin-positive stromal cells are able to differentiate into GFAP (glial fibrillary acidic protein)-positive cells when they are co-cultivated with neural stem cells. We thus demonstrated that adult rat stromal cells in culture express nestin in absence of serum after passaging the cells at least ten times, and we suggest that nestin expression by these cells might be a prerequisite for the acquisition of the capacity to progress towards the neural lineage.