Charles Easley, Ph.D.
K22ES025418, R01ES025775, R24ES028528, P30ES019776
NIEHS grantees reported that exposure to polybrominated biphenyl (PBB) 153, a type of brominated flame retardant, alters DNA methylation in sperm. DNA methylation refers to heritable changes in gene expression that occur with no alteration to the DNA sequence. PBB153 is known to be toxic to those who are directly exposed. The new study indicates that exposure may also harm future generations.
In 1973, a chemical company that manufactured both a brominated flame retardant and a nutritional supplement mistakenly shipped hundreds of pounds of the flame retardant, instead of the nutritional supplement, to grain mills around Michigan. The flame retardant was incorporated into animal feed, which introduced it into the food chain. As a result, an estimated 6.5 million Michigan residents consumed PBB-contaminated animal products.
The researchers found that circulating levels of PBB153, the primary component of the brominated flame retardant, were associated with methylation of genes in the sperm of men involved in a Michigan PBB study. Based on this information, they studied sperm in the lab and found that exposure to PBB153 decreased methylation at regions of DNA that control imprinted genes, which are essential for fetal growth and play an important role in other aspects of development.
According to the authors, the effects of PBB on epigenetic regulation in sperm may lead to developmental effects in offspring, which could explain some of the endocrine-related health effects that have been observed among children of PBB-exposed parents.
Citation: Greeson KW, Fowler KL, Estave PM, Thompson SK, Wagner C, Edenfield RC, Symosko KM, Steves AN, Marder EM, Terrell ML, Barton H, Koval M, Marcus M, Easley CA 4th. 2020. Detrimental effects of flame retardant, PBB153, exposure on sperm and future generations. Sci Rep 10(1):8567.