Interestingly, different from our results, Hwang et al. recently reported that the treatment of FPS at the dose of 280 mg/kg/d plus calcium carbonate could raise BMD and bone ash weight in 40 weeks old C57BL/6j female mice within 4 weeks (Hwang et al., 2016); Besides, the level of serum FGF23 (circulating FGF23) can be decreased by the treatment of metformin for 8 weeks in the same CKD–MBD rat model-induced by adenine administration (Neven et al., 2018). The gene discussed is FGF23; the disease is Marchiafava-Bignami disease.