The effects of preeclampsia and oxygen environment on endothelial release of matrix metalloproteinase-2.

BACKGROUND: There is evidence of altered vascular endothelial function in women with preeclampsia as well as in the endothelial cells from umbilical vessels of preeclamptic pregnancies. Matrix metalloproteinase (MMP)-2 is elevated in the plasma of preeclamptic women and is a mediator of vascular reactivity; however, whether MMP-2 release is altered in preeclamptic endothelial cells is unknown. We hypothesize that MMP-2 release is enhanced in endothelial cells from preeclamptic compared with uncomplicated pregnancies and that this phenomenon may be mediated by an oxygen-dependent mechanism. Our specific hypothesis is that cells from normal pregnancies will demonstrate enhanced MMP-2 release at low oxygen (< 0.5%, 2%) compared to high oxygen (20%), thus mimicking the behavior of preeclamptic cells. METHODS: Human umbilical vein endothelial cells (HUVECs) from preeclamptic pregnancies (n = 4) and normal pregnancies (n = 4) were incubated for 12 hr in standard culture conditions (20% oxygen). In a separate series of experiments, HUVECs from normal pregnancies (n = 6) were incubated for 12 hr at < 0.5%, 2%, and 20% oxygen. Supernatants were analyzed for MMP-2 and tissue inhibitors of metalloproteinases (TIMP)-1 and -2. RESULTS: The HUVECs from women with preeclampsia demonstrated significantly enhanced release of MMP-2 (p < 0.05), TIMP-1 (p < 0.001), and TIMP-2 (p = 0.01) compared to normal cells. MMP-2 release from HUVECs from uncomplicated pregnancies was significantly elevated at 2% oxygen compared to < 0.5% and 20% oxygen (p < 0.05). TIMP-1 and -2 secretion was not altered with varying oxygen. CONCLUSIONS: Preeclamptic endothelial cells demonstrate significantly enhanced MMP-2, TIMP-1 and TIMP-2 release compared to normal cells. Our data show that there are significant effects of oxygen tension on MMP-2 release from normal cells; however, the magnitude of the enhanced release is small when compared to the differences in MMP-2 release in cells from preeclamptic and normal pregnancies. Furthermore, TIMP-1 and -2 release is not affected by changes in oxygen. It is unlikely that oxygen is a key mediator of the enhanced MMP-2, TIMP-1 and TIMP-2 release observed in preeclamptic cells.

Vascular endothelial growth factor activating matrix metalloproteinase in ascitic fluid during peritoneal dissemination of ovarian cancer.

The role of vascular endothelial growth factor (VEGF) during peritoneal dissemination of ovarian carcinoma and the association with tumor microvessel density (MVD) and matrix metalloproteinase (MMP) activity was investigated. To this end, MVD, tumor tissue and ascitic fluid levels of VEGF, and MMP activity of ascitic fluid were examined in patients with ovarian cancer and benign ovarian tumor. The effect of ascites on cell growth, cell invasion activity and angiogenesis was investigated in vitro. Ascitic fluid and tumor tissue samples were obtained from 15 patients with benign ovarian tumor and 24 patients with ovarian carcinoma. Tissue extract and ascitic fluid levels of VEGF were measured using enzyme immunoassay. Tumor microvessels were detected immunohistochemically. MMP activity was measured by gelatin zymography. For the in vitro experiment, the SKOV-3 human ovarian carcinoma cell line was utilized. Cell growth was examined using MTT-assay, cell invasion activity was measured by Matrigel in vitro invasion assay, and neovascularization was assessed using an angiogenesis kit. VEGF levels in tissue extract and ascitic fluid, MVD, expression of active form MMP-2 in ascitic fluid and ascites volume were higher in ovarian cancer patients than in benign ovarian tumor patients. In addition, these were elevated in stage III and IV diseases compared to stage I and II diseases in ovarian cancer patients. MVD and expression of active form MMP-2 in ascitic fluid were closely correlated with VEGF level in tissue extracts, and MVD and ascites volume were closely correlated with VEGF level in ascitic fluid. Cell invasive activity and angiogenesis activity increased when cells were exposed to ascites. These increases were apparent when exposed to ascites obtained from ovarian cancer patients and were related to VEGF concentrations of ascitic fluid and expression of active form MMP-2 in ascitic fluid. The increased VEGF secreted from tumor cells is suggested to enhance tumor growth through angiogenesis, to produce ascites and to elevate ascitic VEGF concentrations and expression of active form MMP-2. The progression of peritoneal involvement may be induced by elevated VEGF and expression of active form MMP-2, followed by increased VEGF in the primary tumor. Control of VEGF in the primary tumor may become an effective strategy against peritoneal dissemination of ovarian carcinoma.