Postnatal Fate of Donor Hematopoietic Stem Cells After Transamniotic Stem Cell Therapy

Transamniotic Stem Cell Therapy is a minimally invasive alternative for fetal administration of syngeneic/autologous hematopoietic stem cells (HSCs). We sought to examine donor HSC fate after birth following HSC-based Transamniotic Stem Cell Therapy in a healthy syngeneic model.

Sixteen time-dated pregnant Lewis dams underwent volume-matched intra-amniotic injections in all fetuses (n = 124) of either donor HSCs labeled with a firefly luciferase reporter gene (HSC; n = 81) or of acellular luciferase (control; n = 43) on gestational day 17 (E17, term = E21-22). Infused HSCs consisted of syngeneic cells with hematopoietic progenitor identity confirmed by flow cytometry. On postnatal days 7 (P7) and 21 (P21) after birth, samples from 10 neonatal anatomical sites were screened for luciferase activity via microplate luminometry. Maternal samples of serum and bone marrow were screened at either P7 or P21.

Overall survival to term was 44% (54/124). Combined survival to P7 and P21 from term was 72% (39/54), with no significant difference between groups (P = 0.22-1.00). When controlled by the acellular luciferase injections, donor HSCs were identified in the spleen, intestine, liver, and brain on P7 (P = 0.032 to 0.002) but in none of the sites in any neonate on P21. No luciferase activity was detected in any maternal sample.

Although present 1 wk after birth at select neonatal sites, donor HSCs are not detectable at 3 wk of postnatal life after intra-amniotic injection in a healthy syngeneic rodent model, suggesting that transamniotic HSC therapy may be safe and thus amenable to eventual regulatory approval for clinical trials.