To Örebro University

BACKGROUND: Some per- and polyfluoroalkyl substances (PFAS) such as perfluorohexane sulfonic acid (PFHxS), perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) are very long-lived in humans, with serum half-lives of several years. In PFAS hot spots, such as Ronneby, Sweden, high exposures over time have led to markedly elevated serum PFAS levels, which may result in health risks as well as transfer to the next generation through pregnancy and breastfeeding. Bile acid sequestrants and organic anion transporter inhibitors are drug candidates for increasing PFAS elimination in humans.

MATERIALS AND METHODS: This is a cross-over, clinical study in 10 individuals from Ronneby, Sweden. First, participants were given the bile acid sequestrant cholestyramine and the organic anion transporter inhibitor probenecid for 1 week each. Urinary and fecal concentrations were measured prior, during and after the administration. Then, the changes of serum PFAS concentrations during a 12-week intervention with the bile acid sequestrant colesevelam were compared to a control period.

RESULTS: The study population was mainly exposed to PFHxS (serum mean 50 ng/mL, range 5.8-170), PFOS (serum mean 46 ng/mL, range 9.2-130) and PFOA (serum mean 2.2, range 0.7-4.4). Cholestyramine intervention increased the serum adjusted fecal PFOS concentrations by 23.1 times (95 %CI: 13.6, 39.2), while probenecid was associated with 0.79 times (95 %CI 0.63, 1.0) serum-adjusted urinary PFOS concentrations, compared to no intervention. The 12-week intervention with colesevelam resulted in a mean serum PFOS decline of 38 % (95 %CI -42, -34), compared to 2 % (95 %CI -8, 5) in the control period. The decline was smaller for PFHxS and PFOA.

CONCLUSIONS: Bile acid sequestrants could be used for accelerating PFAS excretion in highly PFAS exposed individuals. Studies are needed to evaluate the risks, costs and benefits of using it for this purpose.