Induction of calcification by serum depletion in cell culture: a model for focal calcification in aortas related to atherosclerosis

Characterization of the sex-specific pattern of angiogenesis and lymphangiogenesis in aortic stenosis

Objective

We aim to analyze sex-related differences in angiogenesis and lymphangiogenesis in aortic valves (AVs) and valve interstitial cells (VICs) from aortic stenosis (AS) patients.

Approach and Results

Totally 230 patients (59% men) with severe AS undergoing surgical valve replacement were recruited. The density of total neovessels was higher in AVs from men as compared to women. Both small and medium neovessels were more abundant in men's AVs. Accordingly, male AVs exhibited higher CD31 and VE-cadherin expressions. The levels of the pro-angiogenic markers, such as vascular endothelial growth factor (VEGF)-A, VEGF receptor (VEGFR)1, VEGFR2, insulin-like growth factor-binding protein-2 (IGFBP-2), interleukin (IL)-8, chemerin, and fibroblast growth factor (FGF)-7, were increased in AVs from men. Transforming growth factor-β expression was higher in male AVs. The expression of antiangiogenic molecules thrombospondin (Tsp)-1, endostatin, and CD36 was upregulated in male AVs, although the levels of Tsp-2, IL-4, IL-12p70, and chondromodulin-1 were similar between both sexes. The number of lymphatic vessels and the expression of the lymphangiogenic markers Lyve-1 and D2-40 was higher in men's AV as well as VEGF-C, VEGF-D, and VEGFR3. Multivariate analyses adjusted for confounders further validated the sex-dependent expression of these targets. VICs isolated from men's AVs secreted higher amounts of the pro-angiogenic factors, VEGF-A, VEGFR1, IGFBP-2, and FGF-7, as well as the pro-lymphangiogenic factors, VEGF-C, VEGF-D, and VEGFR3, than women without changes in antiangiogenic markers.

Conclusion

Our data show that aberrant angiogenic and lymphangiogenic cues are over-represented in male AVs. Importantly, the VIC is a relevant source of multiple morphogens involved in angiogenesis and lymphangiogenesis likely endowing the AV of men with the predominant calcific AS phenotypes.

Innovative technique for the direct determination of proteins in calcified aortic valves

Aortal valve mineralization very frequently causes a genesis of aortic stenosis, which is the most often surgically treated heart disease. Hydroxyapatite deposits have been identified as one of the causes leading to the loss of elasticity of the aortic valves. It is known that phosphates/calcium is accumulated in valve tissues during mineralization, but the mechanism of this process remains unclear. The work is focused mainly on the study of protein composition of mineralized aortic valves by nano-liquid chromatography electrospray ionization in a quadrupole orthogonal acceleration time-of-flight mass spectrometry. New methodological approach based on direct enzymatic digestion of proteins contained in hydroxyapatite deposits was developed for the study of pathological processes connected with osteogenesis. Our objectives were to simplify the traditional analytical protocols of sample preparation and to analyze the organic components of the explanted aortic valves for significant degenerative aortic stenosis. The study of aortic valve mineralization on the molecular level should contribute to understanding this process, which should consequently lead to effective prevention as well as to new ways of treatment of this grave disease.