Intra-Amniotic Delivery of Amniotic-Derived Neural Stem Cells in a Syngeneic Model of Spina Bifida

Abstract

Objective: Neural stem cells (NSCs) may promote spinal cord repair in fetuses with experimental spina bifida. We sought to determine the fate of amniotic-derived NSCs (aNSCs) after simple intra-amniotic injection in a syngeneic model of spina bifida. Methods: Fetal neural tube defects were induced on 20 pregnant Lewis dams by prenatal administration of retinoic acid. Ten dams served as amniotic fluid donors for epigenetic isolation of aNSCs, which were expanded and labeled with 5-bromo-2′-deoxyuridine. The remaining 10 dams received intra-amniotic injections of the processed aNSCs, blindly in all their fetuses (n = 37) on gestational day 17 (term = E21-22). Fetuses with spina bifida underwent screening for the presence of donor aNSCs in the spinal cord at term. Results: Donor cells were identified in 93.3% of the animals with spina bifida, selectively populating the neural placode, typically in clusters, retaining an undifferentiated morphology, and predominantly on exposed neural surfaces, though some were detected deeper in neighboring neural tissue. Conclusions: The amniotic cavity can serve as a route of administration of NSCs in experimental spina bifida. Simple intra-amniotic delivery of NSCs may be a practical adjuvant to regenerative strategies for the treatment of spina bifida.