Adult stem cells have transpired into a powerful therapeutic tool for cell-directed treatments and therapies due to their plasticity, paracrine mechanisms, and immunomodulatory properties1,2,3. The encouraging data from stem cell-based preclinical studies have inspired researchers to work for the bench to-bedside translation. The type of stem cells used for stem cell therapy plays a significant role in successful outcomes. In preclinical and clinical studies, the most widely reported source for mesenchymal stem cells (MSCs) remain bone marrow4,5. However, major drawbacks to using bone marrow-derived stem cells (BMSCs) include their rare population, highly invasive procedures for isolation, and their limited ability to expand. Therefore, alternative sources of MSCs are being explored. In this regard, dental tissues, with their ease of accessibility, enormous plasticity, high regenerative potential, and high proliferative ability, have now been deemed as a rich and potential alternative source of stem cells6,7,8,9,10.
Dental pulp stem cells (DPSCs) were the first type of dental stem cells to be isolated and characterized by Gronthos in 200011. DPSCs have grabbed the attention for tissue engineering applications because of their high proliferation rate, significant differentiation potential, ease of accessibility with effortless culturing, and, most importantly, their ability to be obtained from a discarded tooth without any ethical concern12. The limitations posed by other stem cell sources, such as BMSCs and adipose-derived stem cells (ADSCs), in their isolation and inadequate self-renewal capacities are circumvented by DPSCs13. Human DPSCs can be obtained from human primary teeth, permanent teeth, wisdom teeth, exfoliated deciduous teeth (SHEDs), and apical papillae. Moreover, DPSCs can also be isolated from supernumerary teeth, which are generally discarded14. DPSCs express neural crest-associated markers and have the potential to differentiate into neuronal cells both in vitro and in vivo15. In addition to their neurogenic potential, DPSCs can differentiate into other cell lineages, such as osteogenic, chondrogenic, adipogenic, hepatic, and myogenic, when given specific differentiation conditions13. Thus, these multipotent cells hold great potential for cell-based therapy and can be employed for the regeneration of various tissues. Studies have also reported the potential role of DPSCs in the reconstruction of the cornea16, repair of myocardial infarction17, and their potential therapeutic role in diseases like limb ischemia18, Alzheimer's 19, Parkinson's 20, and aging21. Therefore, dental tissue-derived stem cells can be used not only for dental regeneration, but also for the repair and regeneration of non-dental organs like eyes16, hearts17, livers22, bones23 etc.
There are two particular methods for the isolation of an MSC population from pulp tissue - enzymatic digestion and explant culture24,25. Successful establishment of primary cultures without any significant difference in the quantity and properties of DPSCs have been reported by both these methods26. In this study, we have focused on the isolation of DPSCs by the explant method27, since this method generates DPSCs without contamination of hematopoietic and endothelial cells, as compared to enzymatic digestion which can result in fibroblast contamination28.