A comparative study on culture conditions and routine expansion of amniotic fluid-derived mesenchymal progenitor cells

Background: Amniotic fluid (AF) cell populations will be applied in perinatology. We aimed to test the feasibility of large-scale cell expansion. Study Methods: We determined the best out of three published expansion protocols for mesenchymal progenitors (AF samples, n = 4) in terms of self-renewal ability. Characterization was performed based on morphology, surface marker analysis, cytogenetic stability, and differentiation potential. The conditions for the best self-renewal ability were further determined in a consecutive series (n = 159). Results: The medium containing fetal bovine serum (FBS), epidermal growth factor, insulin, transferrin, and tri-iodothyronine, combined with seeding on gelatin-coated wells, best stimulated the growth of cells with mesenchymal features, as demonstrated by flow cytometry; however, only osteogenic differentiation was possible. Large-scale testing (n = 44) failed to confirm a robust self-renewal ability. Better results were obtained (n = 88) using optimized FBS or an increased initial cell density. Eventually over 81% of cultures continued growing after the initial medium change and had mesenchymal features but failed differentiation assays. Discussion: Routine in vitro expansion of AF-derived mesenchymal cells remains problematic. Despite an increase in successful cell cultures from 40 up to 80% using optimized serum and an increased cell density, eventually cells failed to demonstrate differentiation abilities. Routine isolation and expansion from unselected AF samples remains a challenge

Enrichment of collagen plugs with platelets and amniotic fluid cells increases cell proliferation in sealed iatrogenic membrane defects in the foetal rabbit model

OBJECTIVES: The purpose of this study was to evaluate cell proliferation in platelet-enriched collagen plugs with and without addition of amniotic fluid-derived heterologous foetal cells to seal an iatrogenic membrane defect in the foetal rabbit model. METHODS: Amniotic fluid cells were harvested from three donor does at 23 days of gestation (term = 32 days) and labelled with carboxyfluorescein diacetate succinimidyl ester (CFDA-SE). In 42 other does, foetal membrane defects were induced by foetoscopic needle puncture at 23 days of gestation, and closed with either a platelet-enriched collagen plug with (n = 44) or without (n = 32) amniotic fluid cells. At 30 days of gestation, the defects were harvested and assessed microscopically. RESULTS: The plugs enriched with heterologous amniotic fluid cells more commonly had proliferating cells in the centre of the plug than those without cell addition. CFDA-SE labelling confirmed the presence of heterologous amniotic fluid cells over the entire membrane plug. Cell typing showed a mixture of fibroblasts and epithelial cells at the wound edges, whereas in the centre, there was an abundance of fibroblasts. CONCLUSION: When sealing iatrogenic membrane defects in the foetal rabbit model, enrichment of collagen plugs with platelets and amniotic fluid-derived heterologous foetal cells increases local cell proliferation

Mussel-mimetic tissue adhesive for fetal membrane repair: an ex vivo evaluation

Iatrogenic preterm prelabor rupture of membranes (iPPROM) remains the main complication after invasive interventions into the intrauterine cavity. Here, the proteolytic stability of mussel-mimetic tissue adhesive (mussel glue) and its sealing behavior on punctured fetal membranes are evaluated. The proteolytic degradation of mussel glue and fibrin glue were compared in vitro. Critical pressures of punctured and sealed fetal membranes were determined under close to physiological conditions using a custom-made inflation device. An inverse finite element procedure was applied to estimate mechanical parameters of mussel glue. Mussel glue was insensitive whereas fibrin glue was sensitive towards proteolytic degradation. Mussel glue sealed 3.7mm fetal membrane defect up to 60mbar (45mmHg) when applied under wet conditions, whereas fibrin glue needed dry membrane surfaces for reliable sealing. The mussel glue can be represented by a neo-Hookean material model with elastic coefficient C(1)=9.63kPa. Ex-vivo-tested mussel glue sealed fetal membranes and resisted pressures achieved during uterine contractions. Together with good stability in proteolytic environments, this makes mussel glue a promising sealing material for future applications