IL-8 promotes the calcification of human aortic valve interstitial cells, which is prevented through antagonizing CXCR1 and CXCR2 receptors

• Published in: Archives of Cardiovascular Diseases Supplements Vol. 14; no. 1; p. 101
• Main Authors: Dhayni, K., Chabry, Y., Hénaut, L., Ouled-Haddou, H., Avondo, C., Tribouilloy, C., Caus, T., Zibara, K., Kamel, S., Bennis, Y.
• Format: Journal Article
• Language: English
• Published: Elsevier Masson SAS 01.01.2022
• ISSN: 1878-6480
• DOI: 10.1016/j.acvdsp.2021.09.233

Inflammation is a key feature of calcific aortic valve stenosis (CAVS) with no pharmacological treatment until now. We hypothesize that interleukin-8 (IL-8) promotes the calcification of human aortic valve interstitial cells (hVICs). Primary hVICs were isolated from healthy pieces of aortic valves harvested from patients undergoing surgical valve replacement. They were cultured in a pro-calcifying condition (Pi-3.8mM) with or without IL-8 (5 to 50pg/ml) for up to 21 days. Calcification was analysed by alizarin red staining and calcium content was measured with the o-cresolphthalein complexone method. The expression of each of metalloproteases, osteogenic and myofibrotic markers was analysed by RT-qPCR. The expression of IL-8 receptors, CXCR-1 and CXCR-2 was evaluated by Western blot and flow cytometry, and the effects of IL-8 were tested in the presence or absence of SCH527123, an antagonist of CXCR-1 and CXCR-2. Finally, the expression of CXCR-1 and -2 and that of elastin were analysed by immunohistochemistry in the calcified and non-calcified areas of human aortic valve samples. All of these experiments were carried out from valves of at least 5 different donors where a P-value<0.05 was considered statistically significant. Our results showed that IL-8 (15pg/mL) caused a significant ∼2-fold increase in the calcification of hVICs in the Pi condition. In the same condition, IL-8 stimulated the expression of elastin and MMP-12 but reduced that of OPN. These effects of IL-8 were prevented by the addition of SCH527123. In addition, the expression of CXCR-1 and -2 was confirmed in histological samples of human aortic valves. This expression was more pronounced in calcified areas compared to non-calcified areas and co-localized with degraded elastin. We concluded that IL-8 promoted the calcification of hVICs. This effect was prevented by antagonizing CXCR-1 and CXCR-2, which we showed to be expressed by human VICs and aortic valves of patients with CAVS.