Michael K. Chan

Amniotic fluid contains multipotent cells and could be a source of stem cells for clinical use. Amniotic fluid cells (AFCs) are made up of a heterogeneous population of fetal cells that can be retrieved during pregnancy without ethical concerns as it is a standard clinical procedure. Studies of proliferation, multipotent marker expression, differentiation, and gene expression were performed after culturing with dexamethasone, valproic acid, and magnesium sulfate. There were correlations between known drug effects on the human fetus and changes seen in human AFCs in culture, as well as previously undescribed observations in neural and chondrogenic inducibility. Gene expression profiles confirmed these observations. AFC culture may provide a novel method to evaluate pharmacological agents before clinical use in pregnancy.

Objective: The placenta of mid-gestation mice is a known rich source of hematopoietic stem cells. We hypothesized that it is also a source of other multipotent stem cells. Methods: We isolated fetal cells from the murine placenta across the second half of gestation and characterized their expression of surface antigens known to be associated with mesenchymal stem cells (MSCs) on a subset of hematopoietic lineage-negative cells. Using real-time reverse-transcriptase quantitative polymerase chain reaction, we also evaluated the expression of intracellular transcription factors (TFs) known to be associated with renal development and/or multipotent stem cells. Results: Cell phenotypes with surface marker and TF expression consistent with multipotent stem cells of a mesenchymal lineage as well as renal cell progenitors were found in the placenta. The expression of MSC and renal progenitor surface markers varied throughout gestation, but was highest on E12–15 where such cells represented a small but significant percentage of the population. Of the studied TFs, 10 of 11 renal TFs were found at moderate to high levels, and all stem cell TFs were found. Conclusion: The mid-gestation murine placenta may serve as a source of multipotent stem cells and also contains cells which may be renal cell progenitors.