Plasticizer di(2‐ethylhexyl)phthalate interferes with osteoblastogenesis and adipogenesis in a mouse model

Abstract

Plasticizer di(2-ethylhexyl)phthalate (DEHP) can leach from medical devices such as blood storage bags and the tubing. Recently, epidemiological studies showed that phthalate metabolites levels in the urine are associated with low bone mineral density (BMD) in older women. The detailed effect and mechanism of DEHP on osteoblastogenesis and adipogenesis, and bone loss remain to be clarified. Here, we investigated the effect and mechanism of DEHP and its active metabolite mono(2-ethylhexyl)phthalate (MEHP) on osteoblastogenesis and adipogenesis. The in vitro study showed that osteoblast differentiation of bone marrow stromal cells (BMSCs) was significantly and dose-dependently decreased by DEHP and MEHP (10-100 µM) without cytotoxicity to BMSCs. The mRNA expressions of alkaline phosphatase, Runx2, osteocalcin (OCN), Wnt1, and β-catenin were significantly decreased in DEHP- and MEHP-treated BMSCs during differentiation. MEHP, but not DEHP, significantly increased the adipocyte differentiation of BMSCs and PPARγ mRNA expression. Both DEHP and MEHP significantly increased the ratios of phosphorylated β-catenin/β-catenin and inhibited osteoblastogenesis, which could be reversed by Wnt activator lithium chloride and PPARγ inhibitor T0070907. Moreover, exposure of mice to DEHP (1, 10, and 100 mg/kg) for 8 weeks altered BMD and microstructure. In BMSCs isolated from DEHP-treated mice, osteoblastogenesis and Runx2, Wnt1, and β-catenin expression were decreased, but adipogenesis and PPARγ expression were increased. These findings suggest that DEHP and its metabolite MEHP exposure may inhibit osteoblastogenesis and promote adipogenesis of BMSCs through the Wnt/β-catenin-regulated and thus triggering bone loss. PPARγ signaling may play an important role in MEHP- and DEHP-induced suppression of osteogenesis. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:1124-1134, 2018.

Effects of Di(2-ethylhexyl)phthalate on Bone Metabolism in Ovariectomized Mice

“…In hepatic tissues, DEPH modulates some genetic pathways like PPAR-α signaling pathways and Janus kinase/signal transducers and activators of transcription pathway [22] and in ovarian tissues DEHP dysregulated proapoptotic factors and antiapoptotic factors and altered levels of proteins in phosphatidylinositol 3 kinase (PIsK) signaling pathways. [2324] In a recently reported study by Chiu et al[25], they suggested that DEHP and MEHP exposure may inhibit osteoblastogenesis and promote adipogenesis of bone marrow stromal cells in a mouse model. The downregulation of Wnt/β-catenin signaling and the upregulation of PPAR-γ pathway may contribute to the inhibitory effects of DEHP or MEHP on osteoblast differentiation and thus triggering bone loss.…”

Adipogenesis Regulation and Endocrine Disruptors: Emerging Insights in Obesity

“…Additionally, phthalates have also been related to an alteration in osteoblast homeostasis and adipogenesis in the bone marrow. Studies of Chiu et al [74], in cell cultures of bone marrow stromal cells exposed to different concentrations of MEHP, showed a decrease in differentiation towards osteoblasts and a concomitant increase in adipogenesis.…”

Gender difference of CCAAT/enhancer binding protein homologous protein deficiency in susceptibility to osteopenia

“…The left and right tibias and femurs were isolated. The left tibias were punched by the syringe to isolate the bone marrow stromal cells (BMSCs) and cultured as previously described . The right tibias were fixed in 4% formaldehyde/phosphate‐buffered saline (PBS) solution for 2 days.…”

“…The left tibias were punched by the syringe to isolate the bone marrow stromal cells (BMSCs) and cultured as previously described. 17 The right tibias were fixed in 4% formaldehyde/phosphate-buffered saline (PBS) solution for 2 days. Following, samples were transferred to 75% ethanol/PBS solution and detected the bone mineral density (BMD) and microstructure by microcomputed tomography (m-CT).…”