Immunohistochemical characteristics of aortic valve in the case of atherocalcinosis

Objective: According to the results of the Euro-Heart Survey on Vascular Heart Disease the most common pathology is nonrheumatic aortic steno­sis, it is also called as calcific aortic valve stenosis (CAVS), as in its pathogenesis the process of biomineralization of valve cusps and ring plays the main role Method: 30 samples of mineralized aortic valves (I group) and 10 sam­ples of aortic valve without evidence of biomineralization (II group - control) were studied. Immunohistochemical study of expression of col­lagen I, CD68, MPO, S100A9), caspase3 andosteopontin was conducted in AV tissue of both groups. Results: In CAV tissues the fibrillar component (collagen I) growths was found, but the quantitative compositions of circulating inflammatory cells (CD68+) are not significantly different from the control group. CAVs contain much more MPO+ -cells (p< 0.001) in comparison to the group of AV without biomineralization. Our data show a significant increase of the S100A9 and OPN expression in the mineralized tissue of AVs (p < 0.01). Also a higher expression level of Casp3 and MPO was found in CAVs (p< 0.05). Conclusion: High Casp 3 expression confirms the increased level o f cell elimination in the CAVs tissue, which is obviously connected with the impact of high local concentrations ofS100A9. These facts can contribute to the development of pathological biomineralization o f AV. Since osteopontin inhibits the hydroxyapatite formation by binding to the surface of the crystals, its hyperproduction is a counteracting factor against biomin­eralization in AV tissue