Abstract
Activated macrophages within the arterial wall secrete matrix-degrading metalloproteinases (MMPs) that weaken the atherosclerotic plaque and contribute to its fissuration. Preclinical studies have shown that calcium antagonists may reduce atherogenesis in the arterial wall. In the present study we evaluated the effect of lacidipine on 92-kDa gelatinase B (MMP-9) expression in human macrophages in cultures. Cells were treated for 24 h with lacidipine and the conditioned media were analyzed. Lacidipine (1–20 μM) significantly reduced, in a dose-dependent manner, MMP-9 potential gelatinolytic capacity up to 50%. When MMP-9 expression was stimulated by treatment with phorbol esters or tumor necrosis factor-α, lacidipine was able to inhibit this enhanced gelatinolytic capacity up to 50 and 60%, respectively. Western blot analysis and enzyme-linked immunosorbent assay showed a reduction of MMP-9 protein actually released by cells. The addition of lacidipine in the incubation media determined no significant variation in Ca2+ concentration. The drug did not affect MMP-9 mRNA levels, but it effectively reduced the amount of both active and total free MMP-9 secreted by human macrophages. Lacidipine reduced also the secretion of the tissue inhibitor of metalloproteinase-1 (TIMP-1); however we observed an overall reduction of the gelatinolytic activity of the cells. Finally, peritoneal macrophages, obtained from mice treated with lacidipine, showed a reduced secretion of MMP-9. Together, our data indicate that lacidipine may potentially exert an antiatherosclerotic activity by modulating the secretion of MMP-9 by macrophages. This, in addition to the previously demonstrated inhibition of cholesterol esterification, may contribute to increase plaque stability.
Footnotes
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Send reprint requests to: S. Bellosta, Ph.D., Institute of Pharmacological Sciences, University of Milan, via Balzaretti 9, 20133 Milan, Italy. E-mail: Stefano.Bellosta{at}unimi.it
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This study was supported in part by the Italian National Council for Research (Consiglio Nazionale delle Ricerche) and by Ministero dell'Universitá e della Ricerca Scientifica e Tecnologica (Italian Government).
- Abbreviations:
- MMP
- matrix metalloproteinase
- TIMP
- tissue inhibitor of metalloproteinase
- DMEM
- Dulbecco's modified Eagle's medium
- BSA
- bovine serum albumin
- PMA
- phorbol-12-myristate-13-acetate
- TNF-α
- tumor necrosis factor-α
- PBS
- phosphate-buffered saline
- PMSF
- phenylmethylsulfonyl fluoride
- ELISA
- enzyme-linked immunosorbent assay
- Received July 31, 2000.
- Accepted November 21, 2000.
- The American Society for Pharmacology and Experimental Therapeutics
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