Deciphering the Cellular Effects of Strontium Chloride and Potassium Carbonate on Induced Pluripotent Stem Cells and Their Derivative Cardiomyocytes

Background: /Objectives: Toothpaste ingredients such as strontium chloride (SrCl₂) and potassium carbonate (K₂CO₃) are recognized for their desensitizing and remineralizing ef-fects but may be absorbed through the oral mucosa. Their potential cytotoxic and cardio-toxic properties, however, remain inadequately characterized. Here, we investigated the effects of SrCl₂ and K₂CO₃ on mouse-induced pluripotent stem cells (iPSCs) and iPSC-derived cardiomyocytes (iPSC-CMs). Methods: Cells were exposed to varying con-centrations of each compound for up to 72 h. Real-time cell analysis (xCELLigence RTCA Cardio system) was used to assess proliferation, and flow cytometry was used to evaluate cell viability. Functional properties of iPSC-CMs were examined using multi-electrode ar-ray (MEA) recordings and the xCELLigence based impedance measurements. Cardiac marker expression was examined via immunofluorescence and quantitative RT-PCR. Results: Both SrCl₂ and K₂CO₃ affected iPSCs proliferation and reduced viability in a dose- and time-dependent manner, accompanied by altered embryoid body (EB) morphology and increased cell death. In iPSC-CMs, both compounds downregulated keys cardiac genes and disrupted spontaneous beating activity, with effects intensifying at the higher concentrations. Conclusions: These results demonstrate that SrCl₂ and K₂CO₃ induced dose-dependent cytotoxic and arrhythmogenic effects on iPSCs and iPSC-CMs. At elevated concentrations, these compounds impair iPSC-CMs function and may pose safety con-cerns upon chronic exposure. Further mechanistic and long-term in vivo studies are war-ranted to assess their potential cardiotoxic risk in consumer oral care products.