Lanthanum-containing bioparticles are associated with the influence of lanthanum on high phosphate mediated bone marrow stromal cells viability

Lanthanum (La)-based binder appears effective in reducing serum inorganic phosphate (Pi) levels among chronic dialysis patients, yet concern remains about La accumulation in bone during long-term oral administration. In this study, the effect of lanthanum chloride (LaCl 3 ) on bone marrow stromal cells (BMSCs) viability was investigated under high Pi situation. We found low concentration (10 −9 M) of LaCl 3 increased BMSCs viability, while high concentration (10 −5 M) of LaCl 3 not only inhibited BMSCs viability but also stimulated high Pi induced cell apoptosis. In addition, La-containing calcium phosphate (CaP) particles can be detected on cell surfaces and inside cells. We also found that inhibition of CaP formation by adding sodium pyrophosphate, a recognized inhibitor of hydroxyapatite formation, abrogated LaCl 3 induced the BMSCs viability. For isolated La-containing CaP particles, the particle size increased and crystal phase switched with elevated concentration of LaCl 3 . These results demonstrated that La-containing CaP particles were associated with the process of LaCl 3 mediated BMSCs viability and the physicochemical properties of these particles played an important role in modulating BMSCs function.