A study to determine if human umbilical cord hematopoietic stem cells can survive in baboon extra-embryonic celomic fluid: a prerequisite for determining the feasibility of in-utero stem cell xeno-transplantation via celocentesis.

Objectives: To determine if: (1) human umbilical cord stem cells could survive for 20 h in extra-embryonic celomic fluid obtained at 40 days of development from baboon pregnancies by ultrasound-guided celocentesis and, (2) human hematopoietic stem cell survival could be enhanced by adding increasing concentrations of hematopoietic stem cell culture medium to the celomic fluid.

Methods: CD34+ cells were isolated from umbilical cord blood using a magnetic activated cell sorter and flow cytometry. Cells were then cultured in five platforms containing different combinations of baboon extra-embryonic celomic fluid and hematopoietic stem cell culture medium to determine cell survival kinetics over a 20-hour period in each of the conditions.

Results: Human umbilical cord stem cells can survive for at least 20 h in baboon's celomic fluid. Chi-square for linear trends demonstrated that the number of viable cells was significantly enhanced by adding the increasing concentrations of culture medium to the celomic fluid (29% cell survival in pure celomic fluid, 48% at 1:8, 50% at 1:2, 54.5% at 1:1, 61% in pure culture medium; p < 0.001).

Conclusions: Human umbilical cord stem cells survive in baboon celomic fluid and cell survival improves when the celomic fluid is mixed with greater concentrations of hematopoietic stem cell culture medium. Based on these findings, future in-vivo experiments in the pregnant baboon animal model can be directed at determining whether in-utero injection of human hematopoietic stem cells prior to 10 weeks of pregnancy can lead to permanent chimeras.