Adipogenic activity of chemicals used in plastic consumer products

Abstract Epidemiological studies suggest that obesity cannot solely be attributed to genetics and lifestyle. Accordingly, other environmental factors, such as the exposure to metabolism disrupting chemicals (MDCs), must contribute. Bisphenols or phthalates, prominent chemicals used in plastic, disrupt metabolism and promote obesity in cell and animal models. However, these compounds represent only a very small fraction of plastic chemicals. To investigate whether MDCs are present in plastics, we characterized the adipogenic activity of the chemical mixtures extracted from consumer products covering eight major polymers. We conducted adipogenesis assays with 3T3-L1 cells using high-content fluorescence imaging combined with reporter gene assays for peroxisome proliferator-activated receptor γ (PPARγ) and glucocorticoid receptor (GR), as well as nontarget high-resolution mass spectrometry. Eleven out of 34 plastic products contained chemicals inducing adipogenesis. Polyvinyl chloride (PVC) and polyurethane (PUR), followed by polypropylene (PP), polystyrene (PS), and low-density polyethylene (LDPE) products induced potent adipogenic responses. Compared to rosiglitazone, adipocytes were larger and accumulated more triglycerides in 9 active samples. None of the samples activated GR, and no or a low activation of PPARγ was observed for most adipogenic samples. In total, the products contained 55,300 extractable chemicals, out of which we tentatively identified 2364 unique compounds, including 11 known MDCs. Our results suggest that plastic consumer products contain potent mixtures of MDCs that induce adipogenesis and may promote development to unhealthy adipocytes via PPARγ- and GR-independent mechanisms. Other than well-known MDCs are likely causing these effects.