Bisphenol A exposure is associated with in vivo oestrogenic gene expression in adults

Bisphenol A (BPA) is a synthetic oestrogen commonly used in polycarbonate plastic and resin-lined food and beverage containers. Exposure of animal and cell models to doses of BPA below the recommended tolerable daily intake (TDI) of 50 íg/kg/day has been shown to alter specific oestrogen-responsive gene expression, but this has not previously been shown in humans. In the present study, the authors investigated associations between BPA exposure and in vivo oestrogenic gene expression in humans. Ninety-six adult men from the InCHIANTI population study were selected and examined in vivo expression of six oestrogen receptor, oestrogen-related receptor, and androgen receptor genes in peripheral blood leukocytes. The geometric mean urinary BPA concentration was 3.65 ng/mL [95% confidence interval (CI): 3.13, 4.28], giving an estimated mean excretion of 5-84 íg/day (95% CI: 5.00, 6.85), significantly below the current TDI. In age-adjusted models, there were positive associations between higher BPA concentrations and higher ESR2 [oestrogen receptor 2 (ER beta)] expression (unstandardised linear regression coefficient) 0.1804; 95% CI: 0.0388, 0.3221; p ) 0.013) and ESRRA (oestrogen related receptor alpha) expression (coefficient) 0.1718; 95% CI: 0.0213, 0.3223; p ) 0.026): These associations were little changed after adjusting for potential confounders, including obesity, serum lipid concentrations, and white cell subtype percentages. Upper-tertile BPA excretors (urinary BPA > 4.6 ng/mL) had 65% higher mean ESR2 expression than did lower-tertile BPA excretors (0-2.4 ng/mL). The authors concluded that as the activation of nuclear-receptor-mediated pathways by BPA is consistently found in laboratory studies, such activation in humans provides evidence that BPA is likely to function as a xenoestrogen in this sample of adults.

Authors: Melzer, David; Harries, Lorna; Cipelli, Riccardo; Henley, William; Money, Cathryn; McCormack, Paul; Young, Anita; Guralnik, Jack; Ferrucci, Luigi; Bandinelli, Stefania; Corsi, Anna Maria; Galloway, Tamara ;Full Source: Environmental Health Perspectives 2011, 119(12), 1788-1793 (Eng) ;