Hyperglycaemia in vitro alters the proliferation and mitochondrial activity of the choriocarcinoma cell lines BeWo, JAR and JEG-3 as models for humanfirst-trimester trophoblast

Aims/hypothesis. Early intrauterine growth delay in diabetes could be cause d by a reduced growth of the placenta. Our study investigates whether hyper glycaemia in vitro reduces trophoblast proliferation. Methods. First-trimester trophoblast cell models (BeWo, JAR and JEG-3 chori ocarcinoma cells) were cultured for 24 and 48 h with 5.5 mmol/l D-glucose, 25 mmol/l D-glucose (hyperglycaemia) and with an osmotic control. Cell numb er, total protein and nucleic acid content and mitochondrial activity (tetr azolium salt assay) were measured, the cell cycle analysed (FACS, cyclin B1 levels) and apoptosis (Annexin-V) measured. Results. In BeWo cells hyperglycaemia reduced cell number, protein, nucleic acid and cyclin B1 levels. The reduced G(2)/M and increased G(0)/G(1) popu lation after 24 h reflects growth arrest at G(0)/G(1). In JAR cells after 2 4 h the population was arrested in G(0)/G(1), whereas after 48 h the G(0)/G (1) block was abrogated and the cells were arrested at G(2)/M. The net effe ct was an unchanged cell number. In JEG-3 cells hyperglycaemia resulted in fewer cells after 24 h but not after 48 h indicating some adaptation. Mitoc hondrial activity was either stimulated (BeWo) or reduced (JAR, JEG-3) unde r hyperglycaemia. Some of these effects were also induced by hyperosmolarit y alone. Conclusion/interpretation. Hyperglycaemia has the potential to inhibit the proliferation of first-trimester trophoblast cell models. The mechanisms le ading to growth arrest and to changes in mitochondrial activity are complex and depend on differentiation. We hypothesise a hyperglycaemia-induced imp airment of placental growth in the first trimester of a poorly controlled d iabetic pregnancy.