(A) Scheme showing the principle of the measurement. LmnaG609G/+ VSMCs were incubated in MEM media (containing 0.8 mmol/L magnesium; untreated) or in magnesium-enriched MEM media (containing 1.8 mmol/L magnesium; treated) from passage 1 to passage 8. Then, cells were incubated overnight in MEM containing 0.1% FBS and some cells were fixed, as described in the Methods section. Then, cells were incubated in MEM (containing 0.1% FBS) with 1 or 2 mmol/L phosphate, 1.8 mmol/L magnesium (+Mg), 100 µmol/L pyrophosphate (+PPi), or 500 µmol/L phosphonoformic acid (+PFA). After 7 days of incubation, during which the media were replaced daily, the calcium content was measured as described in the Methods section. 