We are in the beginning of the era of regenerative medicine and many researchers are testing adult stem cells to
be used for tissue repair and regeneration in the human body. Many adult stem cells have been discovered since the late
1990’s with more recently a novel adult stem cell described in menstrual blood. The menstrual blood is derived from
shedding of the endometrial lining, specifically the functionalis layer, which contains highly proliferative cells used to
prepare the female body for implementation of a fertilized egg. Cell characterization experiments of stromal stem cells
discovered in menstrual blood have demonstrated cells to be multipotent which can successfully differentiate in vitro into
cell lineages derived from the mesoderm and the ectoderm.
When menstrual blood cells were seeded in culture the average number of adherent cells was 8.50 % with a range of
0.48% to 47.76%. Demonstrating longevity one cell line allowed to grow was subcultured 47 times before complete
senescence and death. The menstrual blood stromal stem cell phenotypic analysis incorporates mesenchymal cell markers
such as CD13, CD29, CD44, CD49f, CD73, CD90, CD105, CD166, MHC Class I and pluripotent embryonic stem cell
markers SSEA-4, Nanog and Oct-4. Karyotypic analysis demonstrated the maintenance of diploid cells without
In conclusion preliminary studies have demonstrated menstrual stem cells are easily expandable to clinical relevance.
Pivotal pre-clinical studies are now underway to test the safety and efficacy of menstrual stem cells in several different
animal models including one for neuroprotection following transplantation into an experimental stroke model. The study
demonstrates menstrual stem cells are a novel cell population that may be routinely and safely isolated to provide a
renewable source of stem cells from child-bearing women.