[OP.2D.02] LYCOPENE INCREASES NITRIC OXIDE BIOAVAILABILITY AND INHIBITS ENDOTHELIAL CELLS MIGRATION. (September 2016) - Dalbeni, A.
Abstract : Objective: Epidemiologic and intervention studies suggest that dietary vegetables containing lycopene may associate with a reduction in cardiovascular risk. Lycopene has antioxidant activity, being the most efficient carotenoid singlet oxygen quencher. Aim of the present study was to explore the effects of lycopene on the synthesis and release of nitric oxide (NO) in endothelial cells and endothelial cells migration, a key step in angiogenesis. Design and method: Cultured human umbilical endothelial cells (HUVECs) were incubated for 30 minutes in the presence or absence of lycopene (2 micromol/L), vascular endothelial growth factor-A (VEGF-A, 10 ng/mL) and the NO-synthase inhibitor L-NAME (300 micromol/L). Confocal microscopy and Diaminofluorescein-FM diacetate (DAF-FM-DA) as NO indicator were used to analyze NO generation. Nitrite/nitrate concentration was measured in the cell culture medium using 2, 3-diaminonaphthalene fluorimetric assay after 30 minutes of exposure to agonists and inhibitors. HUVECs migration was quantified by counting the number of migrated cells (10 fields per well) up to 20 hours after the addition of VEGF using the scratch wound healing assay. Results: An increase in DAF-FM-DA fluorescence was observed in HUVECs with a perinuclear pattern after exposure to lycopene (486.5 ± 142.0 Arbitrary Units, M ± SD, n = 7, p < 0.01), VEGF (472.7 ± 103.4 AU, p < 0.01) or the combination of the two agents with no synergistic effect (460.4 ± 183.2 AU, p < 0.05) compared to controls (293.5 ± 110.9 AU). Nitrite/nitrate concentration in HUVECs culture medium was higher in the presence of lycopene (35.9 ± 25.0 nmol/L, n = 4, P < 0.05), compared to controls (10.4 ± 1.0 nmol/L) and VEGF-A which had no effects. Nitrite/nitrate concentration was reduced by L-NAME (8.6 ± 2.6 nmol/L), demonstrating their generation via NO-synthase. HUVECs migration was stimulated by VEGF-A (967 ± 235 Cells/Field, control: 652.9 ± 118.5, n = 8, p < 0.05) and inhibited by the addition of lycopene (676.1 ± 204.8 C/F, p < 0.01 vs VEGF alone). Conclusions: The present data demonstrate that lycopene increases NO generation and release, as shown by the increase in NO and nitrite/nitrate concentrations, by preventing peroxynitrite formation. Lycopene has biological activity, blunting the increase in cell migration induced by VEGF-A, possibly through NO-depended modulation of VEGF signaling system. The potential of lycopene bioactivity should be further investigated in the setting of vascular inflammation and pathological angiogenesis.