DNA methylation in the pathogenesis of type 2 diabetes

Maternal Obesity Modulates Cord Blood Concentrations of Proprotein Convertase Subtilisin/Kexin-type 9 Levels

Context

In utero exposure to maternal obesity or diabetes is considered a pro-inflammatory state.

Objective

To evaluate whether cord blood proprotein convertase subtilisin/kexin-type 9 (PCSK9), which is regulated by inflammation and metabolic derangements, is elevated in neonates born to overweight, obese, or diabetic mothers.

Methods

A retrospective study in full-term neonates born between 2010 and 2023, at Brigham and Women's Hospital. There were 116 neonates included in our study, of which 74 (64%) were born to overweight/obese mothers and 42 (36%) were born to nonoverweight/nonobese mothers.

Results

Neonates born to overweight/obese mothers had significantly higher cord blood concentrations of PCSK9 compared with neonates born to nonoverweight/nonobese group (323 [253-442] ng/mL compared with 270 [244-382] ng/mL, P = .041). We found no significant difference in cord blood concentrations of PCSK9 between neonates of diabetic mothers compared with neonates of nondiabetic mothers. In multivariate linear regression analysis, higher cord plasma PCSK9 concentration was significantly associated with maternal overweight/obesity status (b = 50.12; 95% CI, 4.02-96.22; P = .033), after adjusting for gestational age, birth weight, male sex, and intrauterine growth restriction.

Conclusion

Neonates born to mothers with overweight/obesity have higher cord blood PCSK9 concentrations compared with the nonoverweight/nonobese group, and higher cord blood PCSK9 concentrations were significantly associated with maternal overweight/obesity status, after adjusting for perinatal factors. Larger longitudinal studies are needed to examine the role of PCSK9 in the development of metabolic syndrome in high-risk neonates born to overweight, obese, or diabetic mothers.

Maternal obesity and gestational diabetes reprogram the methylome of offspring beyond birth by inducing epigenetic signatures in metabolic and developmental pathways

BACKGROUND

Obesity is a negative chronic metabolic health condition that represents an additional risk for the development of multiple pathologies. Epidemiological studies have shown how maternal obesity or gestational diabetes mellitus during pregnancy constitute serious risk factors in relation to the appearance of cardiometabolic diseases in the offspring. Furthermore, epigenetic remodelling may help explain the molecular mechanisms that underlie these epidemiological findings. Thus, in this study we explored the DNA methylation landscape of children born to mothers with obesity and gestational diabetes during their first year of life.

METHODS

We used Illumina Infinium MethylationEPIC BeadChip arrays to profile more than 770,000 genome-wide CpG sites in blood samples from a paediatric longitudinal cohort consisting of 26 children born to mothers who suffered from obesity or obesity with gestational diabetes mellitus during pregnancy and 13 healthy controls (measurements taken at 0, 6 and 12 month; total N = 90). We carried out cross-sectional and longitudinal analyses to derive DNA methylation alterations associated with developmental and pathology-related epigenomics.

RESULTS

We identified abundant DNA methylation changes during child development from birth to 6 months and, to a lesser extent, up to 12 months of age. Using cross-sectional analyses, we discovered DNA methylation biomarkers maintained across the first year of life that could discriminate children born to mothers who suffered from obesity or obesity with gestational diabetes. Importantly, enrichment analyses suggested that these alterations constitute epigenetic signatures that affect genes and pathways involved in the metabolism of fatty acids, postnatal developmental processes and mitochondrial bioenergetics, such as CPT1B, SLC38A4, SLC35F3 and FN3K. Finally, we observed evidence of an interaction between developmental DNA methylation changes and maternal metabolic condition alterations.

CONCLUSIONS

Our observations highlight the first six months of development as being the most crucial for epigenetic remodelling. Furthermore, our results support the existence of systemic intrauterine foetal programming linked to obesity and gestational diabetes that affects the childhood methylome beyond birth, which involves alterations related to metabolic pathways, and which may interact with ordinary postnatal development programmes.