Tissue engineering from human mesenchymal amniocytes: a prelude to clinical trials

Abstract

Purpose The surgical treatment of congenital anomalies using tissues engineered from amniotic fluid-derived mesenchymal cells has been validated experimentally. As a prerequisite for testing the clinical feasibility of this therapeutic concept, this study was aimed to expand human mesenchymal amniocytes in the absence of animal products. Methods Human mesenchymal cells were isolated from amniotic fluid samples (n = 12) obtained at 20 to 37 weeks' gestation. Their phenotypic profiles and cell proliferation rates were compared during expansion under 2 different media, containing either fetal bovine serum or allogeneic human AB serum. Statistical analyses were by the 2-sided Wilcoxon signed rank test and linear regression ( P < .05). Results Mesenchymal cells could be isolated and expanded at any gestational age. There was a greater than 9-fold logarithmic expansion of mesenchymal cells, with no significant differences in the overall proliferation rates based on serum type ( P = .94), or gestational age ( P = .14). At any passage, cells expanded for up to 50 days remained positive for markers consistent with a multipotent mesenchymal progenitor lineage, regardless of the medium used. Conclusions Human mesenchymal amniocytes retain their progenitor phenotype and can be dependably expanded ex vivo in the absence of animal serum. Clinical trials of amniotic fluid-based tissue engineering are feasible within preferred regulatory guidelines.