Dental stem cells have successfully been differentiated into milk producing mammary gland cells, which could hold applications for reconstructive breast surgery.

Researchers at the University of Zurich (UZH) were able to show that dental epithelial stem cells can, under the right conditions, form non-dental tissues, namely mammary glands in female mice.

Dental epithelial stem cells (DESCs) are found in the continuously growing incisors of rodents, were they can generate all epithelial cell populations that compose the incisors. The team led by Thimios Mitsiadis, professor at the Institute of Oral Biology, harvested DESCs from immunocompromised mice, and along with mammary epithelial cells, transplanted the cells into mammary stroma tissue. The stroma, or connective tissue, had been cleared of all mammary cells prior to transplantation. Immunofluorescent and immunohistochemistry analysis were used to track cell fates during the assay. Real Time PCR (RT-PCR) confirmed that all normal mammary cell types were found to have developed including – most surprisingly – fully-functional milk-producing alveolar cells.

The group injected DESCs into the stroma tissue without the addition of mammary epithelial cells in a second set of experiments, leading to the development of small rudimentary branching of milk ducts. Additionally, estrogen-expressing cells detected in analysis indicate that the cells had some capacity to initiate differentiation into milk-producing cells. In some cases, however, cystic structures formed.

This is the first evidence of any cell type capable of de novo formation of mammary ducts moreover, in the absence of mammary epithelium. This study highlights the plasticity and multi-lineage differentiation potential of DESCs. The regeneration of breast tissue for reconstructive surgeries following breast cancer treatment, therefore, appears to be only one of many potential applications of these incredible stem cells.

Stem Cell Recap:

Stem cells hold huge potential for regenerative medicine due to their ability to differentiate into many of the body’s specialised cells. Zygotes, or fertilized eggs, are known as totipotent,meaning they have the capacity to differentiate into any cell type found in the embryo, in addition to extra-embryonic tissues. However, these are not used therapeutically as they cannot be grown for long in vitro.

Stem cells of most interest to scientists are grouped into three forms; adult, embryonic, and induced pluripotent, according to their degree of developmental potential. Embryonic stem (ES) cells harvested from blastocyte-stage embryos can be grown long-term in vitro and generate all cell types – except extra-embryonic. Somatic stem cells found in many tissues including bone marrow and blood can generate two or more cell lineages, are described as multipotent. Finally, through “reverse programming” of ordinary somatic cells in recent years scientists have been able to produce “induced pluripotent stem” (iPS) cells which are analogous to ES cells in their ability to self-renew indefinitely in vitro and potential to generate any cell type.

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