APEX1 and gestational diabetes: Regarding the effect of GDM on fetal tooth development, Chen’s group utilized a GDM rat model and showed that the activation of TLR4/NF-ĸB signaling pathway in dental mesenchymal/epithelial cells and increased DNA methylation due to Apex1 downregulation in dental epithelial stem cells are involved in the defective tooth development in fetuses from GDM mothers [4,17,18].