Intracoronary nitroprusside results in faster, uniform, and uneventful maximal coronary vasodilation during fractional flow reserve measurements

Background: Previous studies have described potential antiatherogenic effects of everolimus after systemic and local stent delivery. However, direct effects of everolimus on foam cells (FC) have not been well characterized. We used an in vitro model to explore the effects of everolimus on macrophage-derived FC. Methods: FC were derived from human THP1 macrophages via incubation with acetylated LDL (100 μg/ml) for 72 h, followed by everolimus treatment (10−5–10−11 M) for 24 h (n=4). FC viability was quantified using calcein AM/DAPI staining via fluorescent microscopy. FC lysates and media supernatants were analyzed for apoptosis/necrosis using a Cell Death Detection ELISA assay (Roche, Pleasanton, CA, USA). Media supernatants were also analyzed for inflammatory cytokines (IL1β, IL8, MCP1, TNFα) using a Procarta immunoassay (Affymetrix, Santa Clara, CA, USA). Gene expression of autophagy (MAP1LC3A), apoptosis (survivin, clusterin), and matrix degradation (MMP1, MMP9) markers were evaluated by a Quantigene Plex assay (Affymetrix). Statistical significance was calculated using one-way ANOVA (Pb.05). Results: Average FC apoptosis was significantly increased (192%, Pb.01) at a high dose of everolimus (10−5 M), with no effects on necrosis at any dose tested. In contrast, everolimus did not affect endothelial (HUVEC) and smooth muscle (HCASMC) cell apoptosis/ necrosis. Calcein AM/DAPI staining showed that FC exposed to everolimus (10−5 M) had significantly decreased viability (27%, Pb.01) compared to control. Everolimus (10−5 M) increased MAP1LC3A (50%, Pb.001) and clusterin (110%, P=.10) and decreased survivin (33%, Pb.004) and MMP1 (122%, Pb.001) gene expression in FC, suggesting that everolimus reduced FC viability through autophagy/apoptosis. MCP1 cytokine expression was significantly decreased (1000%, Pb.001) by everolimus (10−5 M) in FC, suggesting an inhibitory effect on monocyte recruitment. Conclusion: Everolimus, a potent antiproliferative agent used in drug-eluting stents/bioresorbable vascular scaffolds, may inhibit atheroma progression through autophagy/apoptosis of FC and inhibition of monocyte recruitment into the lesion.