Maternal diabetes induces changes in the umbilical cord gene expression

Gestational Weight Gain Relates to DNA Methylation in Umbilical Cord, Which, In Turn, Associates with Offspring Obesity-Related Parameters

Excessive gestational weight gain (GWG) has a negative impact on offspring's health. Epigenetic modifications mediate these associations by causing changes in gene expression. We studied the association between GWG and DNA methylation in umbilical cord tissue; and determined whether the DNA methylation and the expression of corresponding annotated genes were associated with obesity-related parameters in offspring at 6 years of age. The methylated CpG sites (CpGs) associated with GWG were identified in umbilical cord tissue by genome-wide DNA methylation (n = 24). Twelve top CpGs were validated in a wider sample by pyrosequencing (n = 87), and the expression of their 5 annotated genes (SETD8, TMEM214, SLIT3, RPTOR, and HOXC8) was assessed by RT-PCR. Pyrosequencing results validated the association of SETD8, SLIT3, and RPTOR methylation with GWG and showed that higher levels of SETD8 and RPTOR methylation and lower levels of SLIT3 methylation relate to a higher risk of obesity in the offspring. The association of SETD8 and SLIT3 gene expression with offspring outcomes paralleled the association of methylation levels in opposite directions. Epigenetic changes in the umbilical cord tissue could explain, in part, the relationship between GWG and offspring obesity risk and be early biomarkers for the prevention of overweight and obesity in childhood.

Histopathologic Impacts of Diabetes Mellitus on Umbilical Cord During Pregnancy

As a feto-maternal connection route, the umbilical cord is an important determinant of fetal well-being. The umbilical vessels, unlike major vessels, are not fed by the vasa vasorum, making them more vulnerable to hemodynamic changes induced by maternal diseases such as diabetes mellitus. Furthermore, it may be discarded for exacerbating any perinatal illness. The umbilical cord is the major supporter of a successful neonatal prognosis, since it is the sole organ that initiates life. It plays the most important role in feto-placental relation, as well as what will happen to the infant on extra-uterine life. As a result, the histopathologic alterations in the umbilical cord associated with gestational diabetes mellitus were examined in this review study.

Developmental Effects of (Pre-)Gestational Diabetes on Offspring: Systematic Screening Using Omics Approaches

Worldwide, gestational diabetes affects 2-25% of pregnancies. Due to related disturbances of the maternal metabolism during the periconceptional period and pregnancy, children bear an increased risk for future diseases. It is well known that an aberrant intrauterine environment caused by elevated maternal glucose levels is related to elevated risks for increased birth weights and metabolic disorders in later life, such as obesity or type 2 diabetes. The complexity of disturbances induced by maternal diabetes, with multiple underlying mechanisms, makes early diagnosis or prevention a challenging task. Omics technologies allowing holistic quantification of several classes of molecules from biological fluids, cells, or tissues are powerful tools to systematically investigate the effects of maternal diabetes on the offspring in an unbiased manner. Differentially abundant molecules or distinct molecular profiles may serve as diagnostic biomarkers, which may also support the development of preventive and therapeutic strategies. In this review, we summarize key findings from state-of-the-art Omics studies addressing the impact of maternal diabetes on offspring health.

Persistent Aortic Stiffness and Left Ventricular Hypertrophy in Children of Diabetic Mothers

Background

Fetuses of diabetic mothers develop left ventricular (LV) hypertrophy and are at increased long-term risk of cardiovascular disease. In our previous longitudinal study from midgestation to late infancy we showed persistence of LV hypertrophy and increased aortic stiffness compared with infants of healthy mothers, the latter of which correlated with third trimester maternal hemoglobin A1c. In the present study, we reexamined the same cohort in early childhood to determine if these cardiovascular abnormalities persisted.

Methods

Height, weight, and right arm blood pressure were recorded. A full functional and structural echocardiogram was performed with offline analysis of LV posterior wall and interventricular septal diastolic thickness (IVSd), systolic and diastolic function, and aortic pulse wave velocity. Vascular reactivity was assessed using digital thermal monitoring. Participants also completed a physical activity questionnaire.

Results

Twenty-five children of diabetic mothers (CDMs) and 20 children from healthy pregnancies (mean age, 5.6 ± 1.7 and 5.3 ± 1.3 years, respectively; P = not significant) were assessed. Compared with controls, IVSd z score was increased in CDMs (1.2 ± 0.6 vs 0.5 ± 0.3, respectively; P = 0.006), with one-fifth having a z score of more than +2.0. Aortic pulse wave velocity was increased in CDMs (3.2 ± 0.6 m/s vs 2.2 ± 0.4 m/s; P = 0.001), and correlated with IVSd z score (R² = 0.81; P = 0.001) and third trimester maternal A1c (R² = 0.65; P < 0.0001). Body surface area, height, weight, blood pressure, vascular reactivity, and physical activity scores did not differ between groups. Our longitudinal analysis showed that individuals with greater IVSd, and aortic stiffness in utero, early and late infancy also tended to have greater measures in early childhood (P < 0.001 and P < 0.0001, respectively).

Conclusions

CDMs show persistently increased interventricular septal thickness and aortic stiffness in early childhood.

Transcriptional profiling reveals altered biological characteristics of chorionic stem cells from women with gestational diabetes

Background

Gestational diabetes (GDM) is a common complication of pregnancy. The impact of pregnancy complications on placental function suggests that extraembryonic stem cells in the placenta may also be affected during pregnancy. Neonatal tissue-derived stem cells, with the advantages of their differentiation capacity and non-invasive isolation processes, have been proposed as a promising therapeutic avenue for GDM management through potential cell therapy approaches. However, the influence of GDM on autologous stem cells remains unclear. Thus, studies that provide comprehensive understanding of stem cells isolated from women with GDM are essential to guide future clinical applications.

Methods

Human chorionic membrane-derived stem cells (CMSCs) were isolated from placentas of healthy and GDM pregnancies. Transcriptional profiling was performed by DNA microarray, and differentially regulated genes between GDM- and Healthy-CMSCs were used to analyse molecular functions, differentiation, and pathway enrichment. Altered genes and biological functions were validated via real-time PCR and in vitro assays.

Results

GDM-CMSCs displayed, vs. Healthy-CMSCs, 162 upregulated genes associated with increased migration ability, epithelial development, and growth factor-associated signal transduction while the 269 downregulated genes were strongly linked to angiogenesis and cellular metabolic processes. Notably, significantly reduced expression of detoxification enzymes belonging to the aldehyde dehydrogenase gene families (ALDH1A1/1A2, ALDH2, ALDH3) accounted for downregulation across several metabolic pathways. ALDH activity and inhibitor assays indicated that reduced gene expression of ALDHs affected ALDH enzymatic functions and resulted in oxidative stress dysregulation in GDM-CMSCs.

Conclusion

Our combined transcriptional analysis and in vitro functional characterisation have provided novel insights into fundamental biological differences in GDM- and Healthy-CMSCs. Enhanced mobility of GDM-CMSCs may promote MSC migration toward injured sites; however, impaired cellular metabolic activity may negatively affect any perceived benefit.

Bioinformatics enrichment analysis of genes and pathways related to maternal type 1 diabetes associated with adverse fetal outcomes

Maternal type 1 diabetes mellitus (T1DM) may affect fetal development by altering the gene expression profile of the umbilical cord. The present study aimed to explore the T1DM-induced gene expression changes in the fetal umbilical cord. The raw gene expression profiles (ID: GSE51546) of umbilical cord tissue obtained from six normal mothers (non-diabetic) and six type 1 diabetic mothers were used to identify the differentially expressed genes. Genes that correspond to official gene symbols were selected for protein-protein interaction (PPI) and sub-network construction (combined score > 0.4). Functional annotation for Gene Ontology (GO) and pathway enrichment analysis were performed for genes involved in networking. A total of 110 differentially expressed genes were identified of which 38 were up-regulated while 72 were down-regulated. Only 37 genes were identified to significantly interact with each other. Hub genes including HSPA4, KCTD6, UBE2G1, FBXL19, and EHMT1 were up-regulated while KBTBD7, TRIM32, and NUP were down-regulated. T1DM had a major effect on the expression of genes involved in cellular death and differentiation, cell signaling and communication, protein modification and regulation of GTPase activity. Total 27 pathways were enriched and genes related to Wnt signaling, VEGF signaling, inflammation mediated by chemokine and cytokine signaling pathways, FGF signaling pathways and GnRH receptor pathways were found significantly affected by T1DM. Our results suggest that the T1DM environment seems to alter umbilical cord gene expression involved in the regulation of pathophysiology of the diabetic mother which in turn may lead to long-term consequences in various tissues in infants. This study provides insight into the molecular mechanism underlying the adverse pregnancy outcomes of maternal T1DM.

Genes and transcription factors related to the adverse effects of maternal type I diabetes mellitus on fetal development

PURPOSE

Maternal type I diabetes mellitus (T1DM) increases the risk of adverse pregnancy outcomes, but the corresponding mechanism is unclear. This study aims to investigate the mechanism underlying the adverse pregnancy outcomes of maternal T1DM.

METHODS

Gene expression microarray (GSE51546) was down-loaded from the Gene Expression Omnibus. This dataset included 12 umbilical cord samples from the newborns of T1DM mothers (T1DM group, N = six) and non-diabetic mothers (control group, N = six).

RESULTS

Consequently, 1051 differentially expressed genes (DEGs) were found between the two groups. The up-regulated DEGs enriched in 30 KEGG pathways. HLA-DPA1, HLA-DMA, HLA-DMB, HLA-DQA1, HLA-DQA2 and HLA-DRA enriched in "Type I diabetes mellitus". This pathway was strongly related to 14 pathways, most of which were associated with diseases. Then, a protein-protein interaction network was constructed, and 45 potential key DEGs were identified. The 45 DEGs enriched in pathways such as "Rheumatoid arthritis", "Chemokine signaling pathway" and "Cytokine-cytokine receptor interaction" (e.g. CXCL12 and CCL5). Transcription factors (TFs) of key DEGs were predicted, and a TF-DEG regulatory network was constructed.

CONCLUSIONS

Some genes (e.g. CXCL12 and CCL5) and their TFs were significantly and abnormally regulated in the umbilical cord tissue from the pregnancies of T1DM mothers compared to that from non-T1DM mothers.

Extreme umbilical cord lengths, cord knot and entanglement: Risk factors and risk of adverse outcomes, a population-based study

Objectives

To determine risk factors for short and long umbilical cord, entanglement and knot. Explore their associated risks of adverse maternal and perinatal outcome, including risk of recurrence in a subsequent pregnancy. To provide population based gestational age and sex and parity specific reference ranges for cord length.

Design

Population based registry study.

Setting

Medical Birth Registry of Norway 1999–2013.

Population

All singleton births (gestational age>22weeks<45 weeks) (n = 856 300).

Methods

Descriptive statistics and odds ratios of risk factors for extreme cord length and adverse outcomes based on logistic regression adjusted for confounders.

Main outcome measures

Short or long cord (<10^th or >90^th percentile), cord knot and entanglement, adverse pregnancy outcomes including perinatal and intrauterine death.

Results

Increasing parity, maternal height and body mass index, and diabetes were associated with increased risk of a long cord. Large placental and birth weight, and fetal male sex were factors for a long cord, which again was associated with a doubled risk of intrauterine and perinatal death, and increased risk of adverse neonatal outcome. Anomalous cord insertion, female sex, and a small placenta were associated with a short cord, which was associated with increased risk of fetal malformations, placental complications, caesarean delivery, non-cephalic presentation, perinatal and intrauterine death. At term, cord knot was associated with a quadrupled risk of perinatal death. The combination of a cord knot and entanglement had a more than additive effect to the association to perinatal death. There was a more than doubled risk of recurrence of a long or short cord, knot and entanglement in a subsequent pregnancy of the same woman.

Conclusion

Cord length is influenced both by maternal and fetal factors, and there is increased risk of recurrence. Extreme cord length, entanglement and cord knot are associated with increased risk of adverse outcomes including perinatal death. We provide population based reference ranges for umbilical cord length.

Maternal obesity programs mitochondrial and lipid metabolism gene expression in infant umbilical vein endothelial cells

BACKGROUND/OBJECTIVES

Maternal obesity increases risk for childhood obesity, but molecular mechanisms are not well understood. We hypothesized that primary umbilical vein endothelial cells (HUVEC) from infants of overweight and obese mothers would harbor transcriptional patterns reflecting offspring obesity risk.

SUBJECTS/METHODS

In this observational cohort study, we recruited 13 lean (pre-pregnancy body mass index (BMI) <25.0 kg m^-2) and 24 overweight-obese ('ov-ob', BMI⩾25.0 kg m^-2) women. We isolated primary HUVEC, and analyzed both gene expression (Primeview, Affymetrix) and cord blood levels of hormones and adipokines.

RESULTS

A total of 142 transcripts were differentially expressed in HUVEC from infants of overweight-obese mothers (false discovery rate, FDR<0.05). Pathway analysis revealed that genes involved in mitochondrial and lipid metabolism were negatively correlated with maternal BMI (FDR<0.05). To test whether these transcriptomic patterns were associated with distinct nutrient exposures in the setting of maternal obesity, we analyzed the cord blood lipidome and noted significant increases in the levels of total free fatty acids (lean: 95.5±37.1 μg ml^-1, ov-ob: 124.1±46.0 μg ml^-1, P=0.049), palmitate (lean: 34.5±12.7 μg ml^-1, ov-ob: 46.3±18.4 μg ml^-1, P=0.03) and stearate (lean: 20.8±8.2 μg ml^-1, ov-ob: 29.7±17.2 μg ml^-1, P=0.04), in infants of overweight-obese mothers.

CONCLUSIONS

Prenatal exposure to maternal obesity alters HUVEC expression of genes involved in mitochondrial and lipid metabolism, potentially reflecting developmentally programmed differences in oxidative and lipid metabolism.