Amniotic fluid as a novel source of mesenchymal stem cells for therapeutic transplantation

Abstract

Amniotic fluid was collected transcervically from 6 second-trimester legal terminations of pregnancy (mean gestational age, 19 weeks [range, 17-22 weeks]) according to a protocol approved by the medical ethical review board of our hospital. Amniotic fluid samples, without visible contamination with blood, were centrifuged for 10 minutes at 1283 rpm. Pellets were resuspended and cultured as described previously.¹ Adherent cells were detached with trypsin/EDTA (ethylenediaminetetra-acetic acid) and phenotypically characterized by flow cytometry using fluorescein isothiocyanate– or phycoerythrin-conjugated antibodies. The adipogenic and osteogenic differentiation capacity of culture-expanded MSCs was determined as previously reported.¹ To confirm the fetal origin of cultured cells, a molecular HLA typing was performed on DNA obtained from expanded MSCs, and fetal and maternal blood cells by polymerase chain reaction/sequence-specific oligonucleotide using a reverse dot blot method.⁴