Maternal exposure to cadmium during pregnancy is associated with changes in DNA methylation that are persistent at 9 years of age

Anda R Gliga; Annachiara Malin Igra; Alexander Hellberg; Karin Engström; Rubhana Raqib; Anisur Rahman; Marie Vahter; Maria Kippler; Karin Broberg

doi:10.1016/j.envint.2022.107188

Maternal exposure to cadmium during pregnancy is associated with changes in DNA methylation that are persistent at 9 years of age

Environ Int. 2022 May:163:107188. doi: 10.1016/j.envint.2022.107188. Epub 2022 Mar 22.

Authors

Anda R Gliga¹, Annachiara Malin Igra², Alexander Hellberg², Karin Engström³, Rubhana Raqib⁴, Anisur Rahman⁴, Marie Vahter², Maria Kippler², Karin Broberg²

Affiliations

¹ Institute of Environmental Medicine, Karolinska Institutet, Box 210, 171 77 Stockholm, Sweden. Electronic address: anda.gliga@ki.se.
² Institute of Environmental Medicine, Karolinska Institutet, Box 210, 171 77 Stockholm, Sweden.
³ EPI@LUND, Division of Occupational and Environmental Medicine, Lund University, Sweden.
⁴ International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b), Dhaka, Bangladesh.

PMID: 35334376
DOI: 10.1016/j.envint.2022.107188

Abstract

Background: Cadmium (Cd) exposure during gestation has been associated with altered DNA methylation at birth, but it is not known if the changes in methylation persist into childhood.

Objectives: To evaluate whether gestational Cd-related changes of DNA methylation persist from birth to 9 years of age.

Methods: We studied mother-child dyads in a longitudinal cohort in rural Bangladesh. Cadmium concentrations in maternal blood (erythrocyte fraction; Ery-Cd) at gestational week 14 and in child urine (U-Cd, long-term exposure marker) at 9 years were measured using inductively coupled plasma mass spectrometry. The epigenome-wide DNA methylation was measured in mononuclear cells (PBMCs) prepared from cord blood and peripheral blood at 9 years in 71 children (hereafter referred to as the explorative group) by Infinium HumanMethylation450K BeadChip. Replication of one differentially methylated region (DMR; 9 CpG sites) was performed in PBMCs of 160 9-year-old children (validation group) by EpiTyper MALDI-TOF mass spectrometry.

Results: The median maternal Ery-Cd concentration was 1.24 µg/kg (range 0.35, 4.55) in the explorative group and 0.83 µg/kg (0.08, 2.97) in the validation group. The median U-Cd concentration in the 9-year-old children was 0.26 µg/L (0.09, 1.06) in the explorative group and 0.32 µg/L (0.07, 1.33) in the validation group. In the explorative group, we identified ten DMRs, both in cord blood and in PBMCs at 9 years, that were associated with maternal Ery-Cd. Eight out of the ten DMRs were hypomethylated and three of the hypomethylated DMRs were located in the HLA region on chromosome 6. One of the DMRs (hypomethylated) in the HLA region (upstream of the zinc finger protein 57 homolog, ZFP57 gene) was replicated in the validation group, and we found that it was hypomethylated in relation to maternal Ery-Cd, but not child U-Cd.

Conclusion: Gestational exposure to Cd appears to be associated with regional changes, especially hypomethylated, in DNA methylation that linger from birth up to prepubertal age.

Keywords: Cadmium exposure; Child development; DMR; EWAS; Epigenetic; Programming.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Cadmium / metabolism
Child
DNA Methylation*
Epigenome
Female
Fetal Blood
Humans
Infant, Newborn
Maternal Exposure* / adverse effects
Pregnancy

Substances

Cadmium