N-Acetylcysteine, a glutathione precursor, reverts vascular dysfunction and endothelial epigenetic programming in intrauterine growth restricted guinea pigs.

KEY POINTS: Intrauterine growth restriction (IUGR) is associated with vascular dysfunction, oxidative stress and signs of endothelial epigenetic programming of the umbilical vessels. There is no evidence that this epigenetic programming is occurring on systemic fetal arteries. In IUGR guinea pigs we studied the functional and epigenetic programming of endothelial nitric oxide synthase (eNOS) (Nos3 gene) in umbilical and systemic fetal arteries, addressing the role of oxidative stress in this process by maternal treatment with N-acetylcysteine (NAC) during the second half of gestation. The present study suggests that IUGR endothelial cells have common molecular markers of programming in umbilical and systemic arteries. Notably, maternal treatment with NAC restores fetal growth by increasing placental efficiency and reverting the functional and epigenetic programming of eNOS in arterial endothelium in IUGR guinea pigs. ABSTRACT: In humans, intrauterine growth restriction (IUGR) is associated with vascular dysfunction, oxidative stress and signs of endothelial programming in umbilical vessels. We aimed to determine the effects of maternal antioxidant treatment with N-acetylcysteine (NAC) on fetal endothelial function and endothelial nitric oxide synthase (eNOS) programming in IUGR guinea pigs. IUGR was induced by implanting ameroid constrictors on uterine arteries of pregnant guinea pigs at mid gestation, half of the sows receiving NAC in the drinking water (from day 34 until term). Fetal biometry and placental vascular resistance were followed by ultrasound throughout gestation. At term, umbilical arteries and fetal aortae were isolated to assess endothelial function by wire-myography. Primary cultures of endothelial cells (ECs) from fetal aorta, femoral and umbilical arteries were used to determine eNOS mRNA levels by quantitative PCR and analyse DNA methylation in the Nos3 promoter by pyrosequencing. Doppler ultrasound measurements showed that NAC reduced placental vascular resistance in IUGR (P < 0.05) and recovered fetal weight (P < 0.05), increasing fetal-to-placental ratio at term (∼40%) (P < 0.001). In IUGR, NAC treatment restored eNOS-dependent relaxation in aorta and umbilical arteries (P < 0.05), normalizing eNOS mRNA levels in EC fetal and umbilical arteries (P < 0.05). IUGR-derived ECs had a decreased DNA methylation (∼30%) at CpG -170 (from the transcription start site) and this epigenetic signature was absent in NAC-treated fetuses (P < 0.001). These data show that IUGR-ECs have common molecular markers of eNOS programming in umbilical and systemic arteries and this effect is prevented by maternal treatment with antioxidants.

IL-10 expression in macrophages from neonates born from obese mothers is suppressed by IL-4 and LPS/INFγ.

Obese women offspring have a higher risk of developing chronic diseases associated with an altered immune function. We aim to determine, in neonatal monocyte-derived macrophages, whether maternal obesity is associated with an altered expression and DNA methylation of pro- and anti-inflammatory genes, along with a higher pro-inflammatory response. Cord blood from newborns of obese (Ob) and lean (control) women were obtained at delivery. Monocytes were isolated and differentiated into macrophages, in which M1 (LPS/IFNγ) and M2 (IL-4) polarization were assayed. The mRNA levels for TNFα, IL-1ß, IL-12A, IL-12B, IL-10, and IL-4R were quantified by qPCR and the DNA methylation of candidate genes determined by pyrosequencing. RESULTS: Ob-monocytes had decreased levels of mRNA for pro-inflammatory cytokines IL-1ß, IL-10, and IL-12B compared with controls. Conversely, Ob-macrophages showed increased levels of mRNA for TNFα, IL-4R, and IL-10 compared with controls. M1 response was comparable between both groups, characterized by an important induction of TNFα and IL-1ß. In response to an M2 stimulus, control macrophages showed a decreased expression of inflammatory mediators while Ob-macrophages had an additional suppression of the anti-inflammatory mediator IL-10. Changes in IL-1ß (monocytes) and IL-10 (macrophages) in Ob-monocytes were paralleled by changes in their promoter DNA methylation in fetal monocytes. These results suggest that monocyte-derived macrophages from obese newborns show a basal anti-inflammatory phenotype with an unbalanced response to M1 and M2 polarization stimuli. The presence of changes in DNA methylation of key inflammatory genes in neonatal monocytes suggests an intrauterine programing of immune function by maternal obesity.

Epigenetics in type 1 diabetes: TNFa gene promoter methylation status in Chilean patients with type 1 diabetes mellitus.

TNF-α is a pro-inflammatory cytokine that is involved in type 1 diabetes (T1D) pathogenesis. The TNFa gene is subject of epigenetic regulation in which folate and homocysteine are important molecules because they participate in the methionine cycle where the most important methyl group donor (S-adenosylmethionine) is formed. We investigated whether TNFa gene promoter methylation status in T1D patients was related to blood folate, homocysteine and TNF-α in a transversal case-control study. We studied T1D patients (n 25, mean=13·7 years) and healthy control subjects (n 25, mean=31·1 years), without T1D and/or other autoimmune diseases or direct family history of these diseases. A blood sample was obtained for determination of serum folate, plasma homocysteine and TNF-α concentrations. Whole blood was used for the extraction of DNA to determine the percentage of methylation by real-time PCR and melting-curve analysis. Results are expressed as means and standard deviations for parametric variables and as median (interquartile range) for non-parametric variables. T1D patients showed a higher TNFa gene promoter methylation (39·2 (sd 19·5) %) when compared with control subjects (25·4 (sd 13·7) %) (P=0·008). TNFa gene promoter methylation was positively associated only with homocysteine levels in T1D patients (r 0·55, P=0·007), but not in control subjects (r -0·122, P=0·872). To our knowledge, this is the first work that reports the methylation status of the TNFa gene promoter and its relationship with homocysteine metabolism in Chilean T1D patients without disease complications.

[Global DNA methylation and homocysteine levels are lower in type 1 diabetes patients]. / La metilación global del ADN y los niveles de homocisteína en plasma se encuentran disminuidos en pacientes con diabetes mellitus tipo 1.

BACKGROUND: The worldwide rise in the incidence of Type 1 Diabetes (T1D), and the concordance rate between monozygotic twins (50%), indicate a strong effect of the environment as an underlying factor of this disease. This process can occur throughout epigenetic modifications of gene expression such as DNA methylation, in which several nutrients participate as cofactors. AIM: To determine DNA methylation status in T1D patients and if it is related to plasma levels of folates and homocysteine (Hcy). MATERIAL AND METHODS: We obtained blood samples from 25 T1D patients aged 13.7 ± 5.9 years (11 males) and 25 healthy subjects aged 31.1 ± 7.8 years (16 males). DNA methylation was measured using a colorimetric kit in extracted DNA. Results are expressed as median (interquartile range). RESULTS: Compared with healthy controls, T1D patients had lower global DNA methylation (0.85 (0.91) % and 1.25 (1.16) % respectively, p < 0.02) and Hcy levels (4.8 (1.1) µmol/L and 7.3 (1.4) µmol/L respectively p < 0.01). There were no differences in folate levels between groups. A significant association between folates and global DNA methylation status was observed in T1D patients (r = -0.564, p < 0.01) and healthy subjects (r = 0.440, p = 0.03). CONCLUSIONS: TD1 patients had lower levels of Hcy and global DNA methylation. It is relevant to further investigate if this imbalance also induces epigenetic changes in a gene-specific manner, especially in key genes involved in T1D pathogenesis.

Maternal obesity is associated with a higher number of regulatory-T-cells in newborns without affecting suppression.

BACKGROUND: Maternal obesity (MO) is associated with a higher risk of immune-mediated diseases in the offspring and higher leptin levels in cord blood (CB). This study evaluates the number and function of lymphocyte subtypes in CB related to MO and its relationship with leptin concentration and leptin receptor expression. METHODS: Pregnant women with (n = 32) or without obesity (n = 41) were enrolled at delivery. Cord blood mononuclear cells were separated with Ficoll-Hypaque. B and CD4+, regulatory and effector T cells were quantified by Flow Cytometry. Cord blood leptin concentration was measured by ELISA, and the leptin receptor (sLepR) on Treg cells was determined by Flow Cytometry. RESULTS: MO was associated with higher numbers of CD4+, Treg and effector T cells in the CB of their offspring, without differences in the suppressive function of Tregs. Female offspring had a higher number of these cells and a higher cord leptin concentration. Tregs expressed higher levels of sLepR than effector T cells, without differences between groups. CONCLUSIONS: MO is associated with changes in the newborn's immune profile, more evident in female newborns with higher leptin concentrations. More studies are needed to identify the mechanisms by which the high levels of cord leptin in the newborn of women with obesity could affect the offspring's immune system.

La metilación global del ADN y los niveles de homocisteína en plasma se encuentran disminuidos en pacientes con diabetes mellitus tipo 1 / Global DNA methylation and homocysteine levels are lower in type 1 diabetes patients

Background: The worldwide rise in the incidence of Type 1 Diabetes (T1D), and the concordance rate between monozygotic twins (50%), indicate a strong effect of the environment as an underlying factor of this disease. This process can occur throughout epigenetic modifications of gene expression such as DNA methylation, in which several nutrients participate as cofactors. Aim: To determine DNA methylation status in T1D patients and if it is related to plasma levels of folates and homocysteine (Hcy). Material and Methods: We obtained blood samples from 25 T1D patients aged 13.7 ± 5.9 years (11 males) and 25 healthy subjects aged 31.1 ± 7.8 years (16 males). DNA methylation was measured using a colorimetric kit in extracted DNA. Results are expressed as median (interquartile range). Results: Compared with healthy controls, T1D patients had lower global DNA methylation (0.85 (0.91) % and 1.25 (1.16) % respectively, p < 0.02) and Hcy levels (4.8 (1.1) µmol/L and 7.3 (1.4) µmol/L respectively p < 0.01). There were no differences in folate levels between groups. A significant association between folates and global DNA methylation status was observed in T1D patients (r = -0.564, p < 0.01) and healthy subjects (r = 0.440, p = 0.03). Conclusions: TD1 patients had lower levels of Hcy and global DNA methylation. It is relevant to further investigate if this imbalance also induces epigenetic changes in a gene-specific manner, especially in key genes involved in T1D pathogenesis.