An overview of research on adult stem cells and their role in therapeutic application can be found here:

Maqsood, M., Kang, M., Wu, X., Chen, J., Teng, L., & Qiu, L. (2020). Adult mesenchymal stem cells and their exosomes: Sources, characteristics, and application in regenerative medicine. Life Sciences, 256. https://doi.org/10.1016/j.lfs.2020.118002

Liu, S., Zhou, J., Zhang, X., Lin, Y., Chen, J., Hu, B., Song, J., & Zhang, Y. (2016). Strategies to Optimize Adult Stem Cell Therapy for Tissue Regeneration. International Journal of Molecular Sciences, 17(6), 982. https://doi.org/10.3390/ijms17060982