Adipose-Derived Stem Cells for Dental Tissue Engineering

Objectives: Use of mesenchymal stem cells (MSCs) for tissue engineering is constrained due to phenotypic changes during their expansion and the invasive procedures required for isolation. Adipose-derived stem cells (ADSCs) represent a source of MSCs which can be non-invasively isolated in significant numbers, making them a promising alternative population for cell therapy and tissue engineering applications. In this study we aimed to isolate and expand the stem cell population native to adipose tissue and compare the expansion time, marker profile, and differentiation potential with two alternative MSC sources, bone marrow and dental pulp. Materials and Methods: Following collagenase digestion of inguinal adipose tissue, cell expansion was studied by culturing in á-MEM containing 10% FBS over 14 days. Gene expression for several MSC markers was examined by sqRT-PCR and by FACS analysis for newly isolated and first passage cultures. Osteogenic and adipogenic differentiation was investigated by culturing the cells in multiwell plates for 3 weeks in relevant differentiation media. Results: Newly isolated ADSCs had a population doubling time of 19.3hrs, which was 3.7hrs faster than cells derived from dental pulp . PCR analysis indicated comparable levels of expression for several key MSC markers such as CD44, CD90, Sca1, Nanog, and Nestin. FACS analysis demonstrated that 17% of the total freshly isolated adipose population were CD90 positive and 28% were CD29 positive, whilst passaged cells exhibited 70% CD90 and 89% CD29 positivity. These data corresponded with expression levels for cultured bone marrow-derived MSCs. Cultures demonstrated multipotentiality by differentiation down osteogenic and adipogenic lineages, and further investigations comparing the differentiation potential of FACS sorted populations are ongoing. Conclusion: We conclude that ADSCs exhibit a number of common "stem cell" features, and the ability to isolate these cells non-invasively in significant numbers makes them a promising source of cells for future tissue engineering applications.