Consequences of phthalate exposure during pregnancy

With their research partners from the Universities of Grenoble and Paris in France, and the National Center for Environmental Health and the Harvard T.H. Chan School of Public Health in the United States, the team performed its study on 202 pregnant women in the EDEN cohort and published its unprecedented results in the February 2022 edition of Environment International. The women’s exposure to phthalates was evaluated via the concentration of 11 phthalate-derived metabolites in urine samples collected between 22 and 29 weeks of pregnancy. After birth, the team studied the methylation modifications in the DNA of placental tissue. DNA Methylation (the addition of a methyl group on DNA) is the most-widely studied epigenetic* modification. Increased methylation typically represses the expression of the concerned gene. Beyond being brought about by certain pathologies, methylation modifications can also result from exposure to environmental factors such as cigarette smoke, atmospheric pollution or chemical products, among others.

The women’s exposure to phthalates was evaluated via the concentration of 11 phthalate-derived metabolites in urine samples collected between 22 and 29 weeks of pregnancy. After birth, the team studied the methylation modifications in the DNA of placental tissue. DNA Methylation (the addition of a methyl group on DNA) is the most-widely studied epigenetic* modification. Increased methylation typically represses the expression of the concerned gene. Beyond being brought about by certain pathologies, methylation modifications can also result from exposure to environmental factors such as cigarette smoke, atmospheric pollution or chemical products, among others.

• * Epigenetics

  The term epigenetics describes the range of inheritable phenomena able to modify gene expression without modifying the DNA sequence itself.
  For example, the cells of any one organ are very different from those of another despite their identical DNA. This is possible because the genes expressed in one differ from those expressed in the other, and that difference in gene expression is maintained in cell division.
  Epigenetics can be considered as a sort of molecular memory physically associated with the chromosome. Although less stable than genetic mutations, epigenetic factors are transmitted across several generations.
  Nutrition, stress, temperature, tobacco exposure and even infections can cause epigenetic modifications. Epigenetics is thus, in a certain manner, the dynamic aspect of the genome, giving it a capacity for rapid environmental adaptation. Its mechanisms are flexible and reversible but also complex. Research continues to advance knowledge on the role of epigenetics in a range of diseases including cancer.

Article posted on 15 March 2022

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