Novel isolation strategy to deliver pure fetal-origin and maternal-origin mesenchymal stem cell (MSC) populations from human term placenta.

The placenta is an abundant source of mesenchymal stem/stromal cells (MSC). Although presumed of translationally-advantageous fetal origin, the literature instead suggests a high incidence of either contaminating or pure maternal MSC. Despite definitional criteria that MSC are CD34-, increasing evidence suggests that fetal MSC may be CD34 positive in vivo. We flow sorted term placental digests based on CD34+ expression and exploited differential culture media to isolate separately pure fetal and maternal MSC populations. This method has considerable translational implications, in particular to clinical trials underway with "placental" MSC of uncertain or decidual origin.