• Geng Li, Weihua Qiao, Wenjing Zhang, Fei Li, Jiawei Shi, and Nianguo Dong.
• Department of Cardiovascular Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, People's Republic of China.
• J. Thorac. Cardiovasc. Surg. 2017 Jun 1; 153 (6): 1318-1327.e1.

ObjectiveThe purpose of the present study was to comprehensively compare the phenotype profile of infiltrated macrophages in human noncalcified and calcific aortic valves, and to determine whether the shift of macrophage polarization modulates valvular calcification in vitro.MethodsCell surface markers of macrophages and inflammatory cytokines expression in 90 cases of human noncalcified and calcific aortic valve leaflets were analyzed. The normal aortic valve interstitial cells were isolated and cultured in vitro. After incubation with nonconditioned medium and conditioned medium from unstimulated or lipopolysaccharide-stimulated U937 monocytes, valve interstitial cells were evaluated by osteogenic differentiation markers.ResultsInfiltration of macrophages was enhanced in the calcific aortic valves, and M1 phenotype was the predominant macrophage subsets. In addition, both proinflammatory and anti-inflammatory cytokines were significantly upregulated in the calcific aortic valves. Furthermore, lipopolysaccharide-stimulated monocytes presented with increased expression of inducible nitric oxide synthase and high proportional CD11c-positive (M1) macrophages. Conditioned medium from unstimulated monocytes promoted the osteogenic differentiation of valve interstitial cells in vitro, as evidenced by increased markers such as bone morphogenetic protein 2, osteopontin, and alkaline phosphatase. Conditioned medium from M1 macrophages further enhanced valve interstitial cells calcification. Enzyme-linked immunosorbent assay showed that M1 phenotype macrophages secreted tumor necrosis factors α and interleukin 6, and neutralizing antibodies to these 2 proinflammatory cytokines attenuated induction of osteogenic differentiation and calcification by the conditioned media.ConclusionsBoth total numbers and polarization of macrophage influence the process of calcification in human aortic valve. The shift toward M1 phenotype might promote valve interstitial cell calcification.Copyright © 2017 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.

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