Methylation of serotonin regulating genes in cord blood cells: association with maternal metabolic parameters and correlation with methylation in peripheral blood cells during childhood and adolescence

BACKGROUND

Serotonin (5-hydroxytryptamine, 5-HT) signaling is involved in neurodevelopment, mood regulation, energy metabolism, and other physiological processes. DNA methylation plays a significant role in modulating the expression of genes responsible for maintaining 5-HT balance, such as 5-HT transporter (SLC6A4), monoamine oxidase A (MAOA), and 5-HT receptor type 2A (HTR2A). Maternal metabolic health can influence long-term outcomes in offspring, with DNA methylation mediating these effects. We investigated associations between maternal metabolic parameters-pre-pregnancy body mass index (pBMI), gestational weight gain (GWG), and glucose tolerance status (GTS), i.e., gestational diabetes mellitus (GDM) versus normal glucose tolerance (NGT)-and cord blood methylation of SLC6A4, MAOA, and HTR2A in participants from our PlaNS birth cohort. CpG sites (15, 9, and 2 in each gene, respectively) were selected based on literature and in silico data. Methylation levels were quantified by bisulfite pyrosequencing. We also examined the stability of methylation patterns in these genes in circulating blood cells from birth to adolescence using longitudinal DNA methylation data from the ARIES database.

RESULTS

None of the 203 PlaNS mothers included in this study had preexisting diabetes, 99 were diagnosed with GDM, and 104 had NGT; all neonates were born at full term by planned Cesarean section. Methylation at most CpG sites differed between male and female newborns. SLC6A4 methylation correlated inversely with maternal pBMI and GWG, while methylation at HTR2A site -1665 correlated positively with GWG. None of the maternal metabolic parameters statistically associated with MAOA methylation. DNA methylation data in cord blood and peripheral blood at ages 7 and 15 years were available for 808 participants from the ARIES database; 4 CpG sites (2 in SLC6A4 and 2 in HTR2A) overlapped between the PlaNS and ARIES cohorts. A positive correlation between methylation levels in cord blood and peripheral blood at 7 and 15 years of age was observed for both SLC6A4 and HTR2A CpG sites.

CONCLUSIONS

Methylation of 5-HT regulating genes in cord blood cells is influenced by neonatal sex, with maternal metabolism playing an additional role. Inter-individual variations present in circulating blood cells at birth are still pronounced in childhood and adolescence.

Interleukin-2 gene methylation levels and interleukin-2 levels associated with environmental exposure as risk biomarkers for preterm birth

AIM

To compare interleukin-2 levels (IL-2) and IL-2 gene site 1 methylation levels between preterm newborns (PN) and full-term newborns (FN) and investigate their association with the environmental exposure of their mothers during pregnancy.

METHODS

IL-2 and IL-2 gene site 1 methylation levels were assessed in 50 PN and 56 FN. Newborns' mothers filled in questionnaires about their living and occupational environments, habits, diets, and hobbies.

RESULTS

The mothers of PN were significantly more frequently agrarian/rural residents than the mothers of FN. PN had significantly higher IL-2 levels, and significantly lower methylation of IL-2 gene site 1 levels than FN.

CONCLUSION

IL-2 levels, hypomethylation of the IL-2 gene site 1, and the mother's rural residence (probably due to pesticide exposure) were predictive biomarkers for preterm birth. For the first time, we present the reference values for the methylation of IL-2 gene site 1 in PN and FN, which can be used in the clinical setting and biomonitoring.

The Impact of Hypoglycemia and EPA and DHA Supplementation on Brain-Derived Neurotrophic Factor Level in Pregnant Women with Type 1 Diabetes: A Prospective Cohort Study

BACKGROUND

In addition to its neuroprotective effect, Brain-derived neurotrophic factor (BDNF) also plays a role in glucose and lipid metabolism. This study aims: a) to find changes in the BDNF concentration during pregnancy in type 1 diabetes. b) to prove the effect of DHA and EPA supplementation on changes in BDNF concentrations c) to investigate the impact of hypoglycemia on BDNF concentration.

SUBJECTS AND METHODS

The data from this study were from the PRE-HYPO cohort study. Twenty-one of them were on a standard diabetic diet enriched with EPA and DHA (EPA 120 mg/day and DHA 616 mg/day; Exposed group), and nineteen pregnant diabetic women were on the standard diabetic diet without EPA and DHA supplementation (Non-exposed group). In the first trimester of pregnancy, fifteen pregnant women developed hypoglycemia episodes (≤3.9 mmol/L; HYPO+ group), and twenty-five pregnant women did not have hypoglycemia episodes (HYPO- group).

RESULTS

BDNF concentration significantly decreased during pregnancy from the first to the third trimester, in Non-exposed from 25.1 (22.0-30.2) to 22.1 (16.3-28.2), P<0.05, in the Exposed group from 22.1 (19.8-25.9) to 18.1 (14.8-18.9), P<0.01. Pregnant patients with hypoglycemia episodes (HYPO+ subgroup) had significantly higher BDNF in the third trimester of pregnancy [22.5 (20.6-28.4)] when compared with patients who did not develop hypoglycemia [16.3 (14.3-18.8), P<0.001]. In the third trimester of pregnancy, BDNF and n-6 PUFAs were associated with hypoglycemia (OR 1.818 95 % CI 1.079-3.003, P=0.025; OR 1.103 95 % CI 1.001-1.217, P=0.048). Total F.A.s were inversely associated with hypoglycemia (OR 0.969 95% CI 0.939-0.998, P=0.048).

CONCLUSION

Pregnant women with hypoglycemia (HYPO+ group) had higher concentrations of BDNF in the first and third trimesters of pregnancy compared to those without hypoglycemia. An increase in body weight during pregnancy leads to a decrease in BDNF concentration.

RETRACTED: Growth performance, carcass characteristics, and selected meat quality traits of two strains of Pekin duck reared in intensive vs semi-intensive housing systems

This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/our-business/policies/article-withdrawal). The article has been retracted at the request of the Editor-in-Chief. The article was derived from the thesis of one of the authors: Utjecaj genotipa i sustava drzanja na kvalitetu pacjeg mesa H. Mahmutovic Faculty of Agriculture of Osijek UDK 637.5’65: 636.082(043) view (nsk.hr) The thesis was not acknowledged in the article, contrary to requirement by the journal. Concerns raised by the Thesis supervisors (Drs. G. Kralik and Z. Kralik) were shared with the corresponding author and the different institutions involved. The analysis performed by the journal concluded that the published article and the thesis report a different number of replicates per treatment (n= 6 vs n=3) and differ in their description of batches of animals delivered at the experimental facilities and starting the experiment at different times (n=1 vs n=3). Overall the analysis of the evidence provided indicates that the statistical model applied to the data is not appropriate to the experimental design. As a result, the study is not reproducible, and findings cannot be considered as reliable. Authorship issues were identified. The thesis supervisors were not associated to the publication. Several co-authors (M. Starčević*, H. Mahmutović, N. Glamočlija, M. Bašić, R. Mitrović, R. Marković, M. Bošković, M.Ž. Baltić) recognised that their contributions were erroneously declared so their authorship remains questionable. The Financial Support Statement is incomplete. Evidence was provided that other sources also contributed to financing the study. Apologies are offered to readers of the journal for any inconvenience this may cause.

Early functional and morphological brain disturbances in late-onset intrauterine growth restriction

AIMS

To determine whether the brain disturbances develop in late-onset intrauterine growth restriction (IUGR) before blood flow redistribution towards the fetal brain (detected by Doppler measurements in the middle cerebral artery and umbilical artery). Further, to evaluate predictive values of Doppler arterial indices and umbilical cord blood gases and pH for early functional and/or morphological brain disturbances in late-onset IUGR.

STUDY DESIGN

This cohort study included 60 singleton term pregnancies with placental insufficiency caused late-onset IUGR (IUGR occurring after 34 gestational weeks). Umbilical artery resistance index (URI), middle cerebral artery resistance index (CRI), and cerebroumbilical (C/U) ratio (CRI/URI) were monitored once weekly. Umbilical blood cord samples (arterial and venous) were collected for the analysis of pO2, pCO2 and pH. Morphological neurological outcome was evaluated by cranial ultrasound (cUS), whereas functional neurological outcome by Amiel-Tison Neurological Assessment at Term (ATNAT).

RESULTS

50 fetuses had C/U ratio>1, and 10 had C/U ratio≤1; among these 10 fetuses, 9 had abnormal neonatal cUS findings and all 10 had non-optimal ATNAT. However, the total number of abnormal neurological findings was much higher. 32 neonates had abnormal cUS (53.37%), and 42 (70.00%) had non-optimal ATNAT. Furthermore, Doppler indices had higher predictive validity for early brain disturbances than umbilical cord blood gases and pH. C/U ratio had the highest predictive validity with threshold for adverse neurological outcome at value 1.13 (ROC analysis), i.e., 1.18 (party machine learning algorithm).

CONCLUSION

Adverse neurological outcome at average values of C/U ratios>1 confirmed that early functional and/or structural brain disturbances in late-onset IUGR develop even before activation of fetal cardiovascular compensatory mechanisms, i.e., before Doppler signs of blood flow redistribution between the fetal brain and the placenta.