BPA and BPA alternatives BPS, BPAF, and TMBPF, induce cytotoxicity and apoptosis in rat and human stem cells

Bisphenol A (BPA) is a ubiquitous industrial chemical found in everyday plastic products and materials. Due to scientific findings on the reproductive, developmental, and cellular defects caused by BPA and heightened public awareness, manufacturers have begun to use new chemicals in place of BPA in ?BPA-free? products. These alternatives are chemical analogs of BPA and include dozens of new compounds that have undergone relatively little testing and oversight, including: bisphenol S (BPS), bisphenol AF (BPAF), and the recently developed tetramethyl bisphenol F (TMBPF; the monomer of valPure V70). Here, we used adult female rat adipose-derived stem cells (rASCs) and human mesenchymal stem cells (hMSCs) to compare the toxicities and potencies of these BPA alternatives in vitro. Rat and human stem cells were exposed to BPA (1?10 ?M), 1713-estradiol (E2; 10 ?M), BPS (1?100 ?M), BPAF (3 ? 10- 4?30 ?M), TMBPF (0.01?50 ?M), or control media alone (with 0.01% ethanol) for varying time intervals from 10 min to 24 h. We found significantly decreased cell viability and massive apoptosis in rat and human stem cells treated with each BPA analog, as early as 10 min of exposure, and at low, physiologically relevant doses. BPAF showed extreme cytotoxicity in a dose-dependent manner (LC50 = 0.014 ?M (rASCs) and 0.009 ?M (hMSCs)), whereas TMBPF showed a bimodal response, with low and high concentrations being the most toxic (LC50 = 0.88 ?M (rASCs) and 0.06 ?M (hMSCs)). Activated caspase-6 levels increased in nearly all cells treated with the BPA analogs indicating the majority of cell death was due to caspase6-mediated apoptosis. These results in both rat and human stem cells underscore the toxicity and potency of these BPA analogs, and establish a rank order of potency of: BPAF > TMBPF > BPA > BPS. Further, these and other recent findings indicate that these newer BPA analogs may be ?regrettable substitutions,? being worse than the original parent compound and lacking proper testing and regulation. This work brings to light the need for further toxicological characterization, better regulation, greater public awareness, and the development of safer, more sustainable chemicals and non-plastic products.

Automated summary

BPA alternatives such as BPS, BPAF, and TMBPF exhibit toxicity and potency in rat and human stem cells, with TMBPF being the most toxic, followed by BPA and then BPS. This highlights the need for better regulation, public awareness, and the development of safer alternatives.