Phthalates exposure as a risk factor for gestational diabetes mellitus: Integrated evidence from epidemiological and human liver organoids studies.

Gestational diabetes mellitus (GDM) poses significant risks to both maternal and child health, and its rising incidence necessitates exploration of environmental risk factors. In GDM development, the role of environmental risk factors such as phthalates, a ubiquitous class of endocrine-disrupting chemicals, is not well understood. In this study, we integrated epidemiological and toxicological studies to explore the association between phthalates exposure and GDM risk. We detected ten major phthalates metabolites in serum samples from a GDM case-control cohort and found that the levels of Monobutyl phthalate (MBP), Monoethylhexyl phthalate (MEHP), Monoethyl phthalate (MEP), and Monobenzyl phthalate (MBzP) were significantly elevated in GDM patients compared to healthy controls. By establishing human liver organoids model and high-content imaging method, we demonstrated that MEHP and MBP (2, 10, and 50 μM) enhanced glucose uptake and lipid accumulation in a dose-dependent manner, promoted glycolysis, and altered key metabolic pathways related to insulin resistance. RNA sequencing and pathway analysis revealed that both MEHP and MBP (100 μM) selectively upregulated glycolysis-associated genes while suppressing other glucose metabolism pathways, such as the Tricarboxylic acid cycle and Pentose phosphate pathway, leading to increased pyruvate catabolism and lactate accumulation. Furthermore, liver organoids exhibited greater sensitivity to glucose metabolic disruption in response to MEHP than HepG2 cells, highlighting their suitability as a model for studying phthalates-induced hepatotoxicity. Our study provides novel evidence linking phthalate exposure to GDM risk and elucidates the underlying mechanisms through which phthalates disrupt hepatic metabolism.