Objective: Statins lower cardiovascular event risk, yet, they paradoxically increase coronary artery calcification, a marker consistently associated with increased cardiovascular risks. As calcium deposits influence rupture risk due to stress from compliance mismatch at their surfaces, we hypothesized that statins may lower cardiovascular risk by altering the microarchitecture of calcium deposits. Thus, using mice with preexisting vascular calcification, we tested whether pravastatin reduces the mineral surface area of calcium deposits. Approach and Results: Aged Apoe − /− mice were treated with pravastatin or vehicle for 20 weeks. Aortic calcification was assessed by in vivo sodium fluoride labeled with fluoride 18 isotope-micro-positron emission tomography/micro-computed tomography imaging at weeks 0, 10, and 20 and by histomorphometry at euthanasia. Micro-computed tomography analysis showed that, in both groups, the amount of vascular calcification increased significantly over the 20-week period, but pravastatin treatment did not augment over the controls. In contrast, the micro-positron emission tomography analysis showed that, at week 10, the pravastatin group had less 18 F uptake, suggesting reduced surface area of actively mineralizing deposits, but this decrease was not sustained at week 20. However, a significant difference in the mineral deposit size was found by histomorphometry. The pravastatin group had significantly more aortic microcalcium deposits (<50 µm in diameter) than the controls. The pravastatin group also had more vascular cells positive for alkaline phosphatase activity than the controls. The amount of collagen and osteopontin, additional osteoblastic markers, were not significantly different between the 2 groups. Conclusions: These results suggest that pravastatin treatment alters the microarchitecture of aortic calcium deposits with potential effects on plaque stability.

Calcification, fibrosis, and chronic inflammation are the predominant features of calcific aortic valve disease, a life-threatening condition. Drugs that induce serotonin (5-hydroxytryptamine [5-HT]) are known to damage valves, and activated platelets, which carry peripheral serotonin, are known to promote calcific aortic valve stenosis. However, the role of 5-HT in valve leaflet pathology is not known. We tested whether serotonin mediates inflammationinduced matrix mineralization in valve cells. Real-time reverse transcriptionpolymerase chain reaction analysis showed that murine aortic valve interstitial cells (VICs) expressed both serotonin receptor types 2A and 2B (Htr2a and Htr2b). Although Htr2a expression was greater at baseline, Htr2b expression was induced several-fold more than Htr2a in response to the pro-calcific tumor necrosis factor-α (TNF-α) treatment. 5-HT also augmented TNF-α-induced osteoblastic differentiation and matrix mineralization of VIC, but 5-HT alone had no effects. Inhibition of serotonin receptor type 2B, using specific inhibitors or lentiviral knockdown in VIC, attenuated 5-HT effects on TNF-αinduced osteoblastic differentiation and mineralization. 5-HT treatment also augmented TNF-α-induced matrix metalloproteinase-3 expression, which was also attenuated by Htr2b knockdown. Htr2b expression in aortic roots and serum levels of peripheral 5-HT were also greater in the hyperlipidemic Apoe −/− mice than in control normolipemic mice. These findings suggest a new role for serotonin signaling in inflammation-induced calcific valvulopathy.