Cytogenetic Analysis of Human Dental Pulp Stem Cell Lines

Human embryonic and adult stem cells offer the potential of renewable cell source for diverse regenerative medicine applications. Chromosomal abnormalities in adult stem cell cultures have been characterized by the identification of mosaic subpopulations, which accumulate karyotypic defects (Hoffman and Carpenter, 2005). The therapeutic use of adult stem cells requires that they maintain their genomic stability, and chromosomal integrity, to avoid tumorigenic potential (Ringden et al., 2003; Cowan et al., 2004; Draper et al., 2004; Menendez et al., 2005a,b, 2006). Objective: The aim of this study was to investigate the cytogenetic integrity of established human dental stem cell (DSC) lines. Methods: Chromosome preparations were obtained from in vitro expanded hDSC cultures and analyzed by G banding. Results: Although early DSC cultures appeared normal, karyotypic abnormalities were observed after clonal selection, or after expansion of DSCs without feeder layers. About 70% of cells exhibited chromosomal abnormalities, including polyploidy, aneuploidy and ring chromosomes. Conclusion: These data substantiate the need for further investigation of the cytogenetic stability of expanded DSC populations before widespread use in clinical therapies. We can conclude that the occurrence and potential detrimental effects of such karyotype changes will need to be considered in the development of cell-based transplantation therapies. These studies were supported by the University Federal São Paolo, São Paolo Brazil,CNPq, FAPESP 07/51227-4, Tufts University, Boston, MA, The Center for the Integration of Medicine and Innovative Technology (CIMIT), and NIH grants 7 R03 TW 007665-02 and DE016132(PCY).