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Objective: Gestational diabetes mellitus (GDM) is associated with an increased risk of obesity and insulin resistance in offspring later in life, which might be explained by epigenetic changes in response to maternal hyperglycemic exposure.Research Design and Methods: We explored the association between GDM exposure and maternal blood and newborn cord blood methylation in 536 mother-offspring pairs from the prospective FinnGeDi cohort using Illumina MethylationEPIC 850K BeadChip arrays. We assessed two hypotheses. First, we tested for shared maternal and offspring epigenetic effects resulting from GDM exposure. Second, we tested whether GDM exposure and maternal methylation had an epigenetic effect on the offspring.Results: We did not find any epigenetic marks (differentially methylated CpG probes) with shared and consistent effects between mothers and offspring. After including maternal methylation in the model, we identified a single significant (false discovery rate 1.38 × 10-2) CpG at the cg22790973 probe (TFCP2) associated with GDM. We identified seven additional FDR-significant interactions of maternal methylation and GDM status, with the strongest association at the same cg22790973 probe (TFCP2), as well as cg03456133, cg24440941 (H3C6), cg20002843 (LOC127841), cg19107264, and cg11493553 located within the UBE3C gene and cg17065901 in FAM13A, both susceptibility genes for type 2 diabetes and BMI, and cg23355087 within the DLGAP2 gene, known to be involved in insulin resistance during pregnancy.Conclusions: Our study reveals the potential complexity of the epigenetic transmission between mothers with GDM and their offspring, likely determined by not only GDM exposure but also other factors indicated by maternal epigenetic status, such as maternal metabolic history. [ABSTRACT FROM AUTHOR]

Hyperglycemia and other adverse exposures early in life that reprogram stem cells may lead to long-lasting phenotypic influences over the lifetime of an individual. Hyperglycemia and oxidative stress cause DNA damage when they exceed the protective capabilities of the cell, in turn affecting cellular function. DNA damage in response to hyperglycemia and oxidative stress was studied in human umbilical cord mesenchymal stem cells (hUC-MSCs) from large-for-gestational-age (LGA) infants of mothers with gestational diabetes mellitus (LGA-GDM) and control subjects. We tested the response of these cells to hyperglycemia and oxidative stress, measuring reactive oxygen species (ROS) levels and antioxidant enzyme activities. We find that hUC-MSCs from LGA-GDM infants have increased DNA damage when exposed to oxidative stress. With the addition of hyperglycemic conditions, these cells have an increase in ROS and a decrease in antioxidant glutathione peroxidase (GPx) activity, indicating a mechanism for the increased ROS and DNA damage. This study demonstrates that a memory of in utero hyperglycemia, mediated through downregulation of GPx activity, leads to an increased susceptibility to oxidative stress. The alteration of GPx function in self-renewing stem cells, can mediate the effect of intrauterine hyperglycemia to be propagated into adulthood and contribute to disease susceptibility. [ABSTRACT FROM AUTHOR]

Worldwide, the number of people with diabetes has quadrupled since 1980 reaching 422 million in 2014 (World Health Organization). This distressing rise in diabetes also affects pregnant women and thus, in regard to early programming of adult diseases, creates a vicious cycle of metabolic dysfunction passed from one generation to another. Metabolic diseases are complex and caused by the interplay between genetic and environmental factors. High-glucose exposure during in utero development, as observed with gestational diabetes mellitus (GDM), is an established risk factor for metabolic diseases. Despite intense efforts to better understand this phenomenon of early memory little is known about the molecular mechanisms associating early exposure to long-term diseases risk. However, evidence promotes glucose associated oxidative stress as one of the molecular mechanisms able to influence susceptibility to metabolic diseases. Thus, we decided here to further explore the relationship between early glucose exposure and cellular stress in the context of early development, and focus on the concept of glycemic memory, its consequences, and sexual dimorphic and epigenetic aspects. [ABSTRACT FROM AUTHOR]