Understanding HBCD Metabolic Disruption in Liver Cells

Hexabromocyclododecane (HBCD) is a common flame retardant. It is a persistent organic pollutant. Recently, researchers studied how HBCD affects human liver cells. They focused on HBCD metabolic disruption in HepG2 cells. The team discovered that α-, β-, and γ-HBCD cause cell death. They also noticed that glutathione (GSH) levels dropped significantly. Moreover, γ-HBCD reduced cell viability the most. Consequently, doctors must understand these toxic effects. Furthermore, the oxidative stress varies between the different isomers.

Biotransformation Pathways and Metabolites

The study followed cells for 24 hours. During this time, HepG2 cells processed the isomers differently. Although uptake rates were similar, β-HBCD transformed faster than the others. Notably, the main metabolite was pentabromocyclododecene (PBCDe). Additionally, the cells converted β- and γ-HBCD into α-HBCD. This process is called bioisomerization. Therefore, the liver uses reductive debromination to modify these chemicals. However, the resulting metabolites may still harm cellular health.

Consequences of HBCD Metabolic Disruption

Metabolomic analysis revealed broader damage. HBCD interfered with several vital pathways. Specifically, it altered choline and fatty acid metabolism. In addition, it disrupted purine and glycerophospholipid pathways. Each isomer produced distinct metabolic signatures. Consequently, the researchers concluded that HBCD poses a multi-faceted threat. Because these pathways manage energy and lipids, disruption is dangerous. Therefore, chronic exposure might lead to fatty liver or other disorders.

Frequently Asked Questions

Which HBCD isomer is most toxic to liver cells?

According to the study, γ-HBCD showed the highest cytotoxicity regarding cell viability, while β-HBCD demonstrated the highest rate of biotransformation.

What are the primary metabolic pathways disrupted by HBCD?

HBCD primarily disrupts pathways related to choline, glycerophospholipid, fatty acid, and purine metabolism in HepG2 cells.

Disclaimer: This content is for informational and educational purposes only. It does not constitute medical advice or a professional recommendation. Refer to the latest local and national guidelines for clinical practice.

References

1. Cui J et al. Biotransformation of three hexabromocyclododecane diastereoisomers in HepG2 cells and their cellular metabolomics. Ecotoxicol Environ Saf. 2026 Jun 16. doi: undefined. PMID: 42302342.
2. Stockholm Convention on Persistent Organic Pollutants. Hexabromocyclododecane (HBCD) information sheet.
3. Zhang S et al. Bioaccumulation and biotransformation behaviors of brominated flame retardants in mammalian models. Sci Total Environ. 2025.