Effects of phthalates on mammalian adipose tissue

Adipose tissue plays a critical role in metabolic and endocrine function because it is essential for maintaining systemic energy homeostasis and other related physiological functions. Mammals have four types of adipose tissue: white adipose tissue (WAT), brown adipose tissue (BAT), beige or brite adipose tissue (BeAT), and pink adipose tissue (PAT). These adipose tissues release endocrine factors that modulate diverse processes such as energy storage and expenditure, appetite control, glucose homeostasis, insulin sensitivity, inflammation, lipid metabolism, tissue repair, thermogenesis, and milk production. Proper adipose tissue function relies on hormone receptors and signaling pathways that make the adipose tissues susceptible to disruption by endocrine-disrupting chemicals such as phthalates. Here, we review relevant research on the associations between phthalate exposures and abnormalities in WAT and BAT functions, including phthalate-induced changes in morphology, physiology, and gene expression effects. This review covers in vitro studies, in vivo studies in mammals, and studies in humans. We also discuss important gaps in the literature. Overall, the evidence indicates that phthalates adversely affect WAT and BAT functions. Further studies are needed to better elucidate the mechanisms through which phthalates act in the adipose tissues and to determine the effects of phthalates on human adipose tissues.