Matrixmetalloproteinasen in humanen Endothelzellen -Produktion, Sekretion und Regulierung der endothelialen Matrixmetalloproteinasen-

Matrixmetalloproteinases play an important role in the formation, progression and the complications of atherosclerosis. Likely, Matrixmetalloproteinases are involved in the pathogensis of atherosclerosis by influencing the endothelial barrier by decomposing the basalmembrane and the extracellular matrix. It´s questionable whether endothelial cells produce MMPs and whether the renin-angiotensin-aldosterone system, which is presumed to play a role in the pathogenesis of atherosclerosis, could influence this production. In the first step of this study we detected the gelatinaes MMP-2 and MMP-9 in conditioned medium of HUVECs (human umbilical vein endothelial cells). Zymographic analysis revealed gelatinolytic activity at 72 (pro-MMP-2), 64 (intermediate MMP-2) and 62 kD (active MMP-2). The treatment of HUVECs with bradykinin led to an increased secretion of pro-MMP-2. When we stimulated HUVECs with PMA as well as IL-1β, there was an increased appearence of intermediate and active MMP-2 in the conditioned medium. After the incubation with Cycloheximide, a proteinsynthesis inhibitor, little pro-MMP-2 was found. That means, that most of pro-MMP-2 must have been syntheticized de-novo and that only a few Proteinases were already ready for secretion in vesicels. The transport of these vesicles can be hindered with Colchicin. In the next step we investigated the influence of the renin-angiotensin-aldosterone-system upon the endothelial MMP-2. Aldosterone led to an increased appearence of pro-MMP-2 in the conditioned medium. In contrast to that we found only a tendency of increased pro-MMP-2 in the angiotensin II conditioned medium. In summary we proceed from the assumption that the RAA-System could influence the endothelial MMP-Production. However the low ability to stimulate the endothelial MMP and the high interexperimentel variability don´t allow a final valuation. In the future it will be necessary to carry out more studies to characterize the correlation between MMPs and the renin-angiotensin-aldosterone system.