A novel organ culture model of aorta for vascular calcification

Vascular calcification is a characteristic feature of aging, atherosclerosis, diabetes mellitus, and end-stage renal disease. The use of organ culture provides complementary information that may bridge the gap between traditional cell culture and animal models, and establishes easily controlled experimental conditions. Therefore, we investigated whether organ culture of the aorta could be used as a model of vascular calcification, applying it to animal models of other conditions. Thoracic aortas were dissected from C57BL/6 mice and cultured. To induce vascular calcification, stimulation with inorganic phosphate (Pi) was performed. Morphometric assessment of medial calcium deposition was quantitatively performed, and the amount of dissolved calcium was measured. Pi-stimulation induced calcium deposition in medial layers in a time- and dose-dependent manner. To investigate the phenotypic change of vascular smooth muscle cells (VSMC), the expression of Runx2, osterix, osteocalcin, and ALP activity were determined. Finally, to investigate the influence of Pi-stimulation on the cultured aorta in other models, aortas from streptozotocin (STZ)-induced diabetic mice, aged mice, and Sirt1 knockout (+/-) mice were dissected. These cultures showed a greater tendency for aortic calcification by Pi-stimulation than did control cultures. These results indicate that organ culture of the aorta from mice reflects the state of calcification and suggests that this model will be useful to explore the molecular mechanisms of vascular calcification and the pathology of senescence.