Full-term low birth weight infants have differentially hypermethylated DNA related to immune system and organ growth: a comparison with full-term normal birth weight infants

Epigenome-850K-wide profiling reveals peripheral blood differential methylation in term low birth weight

Aim: We investigate the genome-wide DNA methylation (DNAm) patterns of term low birth weight (TLBW) neonates.Methods: In the discovery phase, we assayed 32 samples (TLBW/control:16/16) using the EPIC 850k BeadChip Array. Targeted pyrosequencing of in 60 samples (TLBW/control:28/32) using targeted pyrosequencing during the replication phase.Results: The 850K array identified TLBW-associated 144 differentially methylated positions (DMPs) and 149 DMRs. Nearly 77% DMPs exhibited hypomethylation, located in the opensea and gene body regions. The most significantly enriched pathway in KEGG is sphingolipid metabolism (hsa00600), and the genes GALC and SGMS1 related to this pathway both show hypomethylation.Conclusion: Our analysis provides evidence of genome-wide DNAm alterations in TLBW. Further investigations are needed to elucidate the functional significance of these DNAm changes.

Epigenome-wide association studies of prenatal maternal mental health and infant epigenetic profiles: a systematic review

Prenatal stress and poor maternal mental health are associated with adverse offspring outcomes; however, the biological mechanisms are unknown. Epigenetic modification has linked maternal health with offspring development. Epigenome-wide association studies (EWAS) have examined offspring DNA methylation profiles for association with prenatal maternal mental health to elucidate mechanisms of these complex relationships. The objective of this study is to provide a comprehensive, systematic review of EWASs of infant epigenetic profiles and prenatal maternal anxiety, depression, or depression treatment. We conducted a systematic literature search following PRISMA guidelines for EWAS studies between prenatal maternal mental health and infant epigenetics through May 22, 2023. Of 645 identified articles, 20 fulfilled inclusion criteria. We assessed replication of CpG sites among studies, conducted gene enrichment analysis, and evaluated the articles for quality and risk of bias. We found one repeated CpG site among the maternal depression studies; however, nine pairs of overlapping differentially methylatd regions were reported in at least two maternal depression studies. Gene enrichment analysis found significant pathways for maternal depression but not for any other maternal mental health category. We found evidence that these EWAS present a medium to high risk of bias. Exposure to prenatal maternal depression and anxiety or treatment for such was not consistently associated with epigenetic changes in infants in this systematic review and meta-analysis. Small sample size, potential bias due to exposure misclassification and statistical challenges are critical to address in future efforts to explore epigenetic modification as a potential mechanism by which prenatal exposure to maternal mental health disorders leads to adverse infant outcomes.

Magnitude and associated factors of low birth weight among term newborns delivered in Addis Ababa public hospitals, Ethiopia, 2021

Only 14% of births had information on birth weight available at the time of birth in Ethiopia. Hence, previous studies underestimate the magnitude and associated factors of low birth weight (LBW). As a result, the goal of this study is to fill those gaps in the previous studies. An institution-based cross-sectional study was employed. Binary logistic regression was used to identify the associated factors. In this study, the magnitude of LBW was 13.06%. History of chronic medical illness (AOR = 3; 95% CI: (1.02, 9.17)), haemoglobin level during pregnancy (AOR = 0.23; 95% CI: (0.10, 0.50)), iron/folic acid supplementation (AOR = 0.27; 95% CI: (0.10, 0.72)) and extra meal during pregnancy (AOR = 3.2; 95% CI: (1.52, 7.00)) were significantly associated with LBW. The magnitude of LBW in this study was comparable to the Ethiopian Demographic and Health Survey (EDHS) report from 2016. It is better to intervene in those identified factors in order to reduce LBW.Impact StatementWhat is already known on this subject? Low birth weight (LBW) accounts for 60-80% of all neonatal deaths each year. In developing countries like Ethiopia, LBW is a major public health concern. Almost half of the world's infants are not weighed at birth, a figure that is especially high in sub-Saharan Africa including Ethiopia.What do the results of this study add? Only 14% of births had information on birth weight available at the time of birth in Ethiopia. Hence, previous studies underestimate the magnitude and associated factors of LBW. To meet the Sustainable Development Goals (SDGs)-2030 targets for neonatal and child mortality, sufficient evidence on the magnitude of LBW and associated factors must be important in order to contribute to the development of timely interventions. A history of chronic medical illness, haemoglobin level, iron/folic acid supplementation and extra meal during pregnancy was associated with LBW.What are the implications of these findings for clinical practice and/or further research? The findings of this study will be useful in developing better health policies to prevent LBW as well as interventions that can target the identified factors.

Pathomechanisms of Prenatally Programmed Adult Diseases

Based on epidemiological observations Barker et al. put forward the hypothesis/concept that an adverse intrauterine environment (involving an insufficient nutrient supply, chronic hypoxia, stress, and toxic substances) is an important risk factor for the development of chronic diseases later in life. The fetus responds to the unfavorable environment with adaptive reactions, which ensure survival in the short run, but at the expense of initiating pathological processes leading to adult diseases. In this review, the major mechanisms (including telomere dysfunction, epigenetic modifications, and cardiovascular-renal-endocrine-metabolic reactions) will be outlined, with a particular emphasis on the role of oxidative stress in the fetal origin of adult diseases.

Epigenetic regulation of pediatric and neonatal immune responses

Epigenetic regulation of transcription is a collective term that refers to mechanisms known to regulate gene transcription without changing the underlying DNA sequence. These mechanisms include DNA methylation and histone tail modifications which influence chromatin accessibility, and microRNAs that act through post-transcriptional gene silencing. Epigenetics is known to regulate a variety of biological processes, and the role of epigtenetics in immunity and immune-mediated diseases is becoming increasingly recognized. While DNA methylation is the most widely studied, each of these systems play an important role in the development and maintenance of appropriate immune responses. There is clear evidence that epigenetic mechanisms contribute to developmental stage-specific immune responses in a cell-specific manner. There is also mounting evidence that prenatal exposures alter epigenetic profiles and subsequent immune function in exposed offspring. Early life exposures that are associated with poor long-term health outcomes also appear to impact immune specific epigenetic patterning. Finally, each of these epigenetic mechanisms contribute to the pathogenesis of a wide variety of diseases that manifest during childhood. This review will discuss each of these areas in detail. IMPACT: Epigenetics, including DNA methylation, histone tail modifications, and microRNA expression, dictate immune cell phenotypes. Epigenetics influence immune development and subsequent immune health. Prenatal, perinatal, and postnatal exposures alter immune cell epigenetic profiles and subsequent immune function. Numerous pediatric-onset diseases have an epigenetic component. Several successful strategies for childhood diseases target epigenetic mechanisms.