Matrix Metalloproteinase Enhances Big-Endothelin-1 Constriction in Mesenteric Vessels of Pregnant Rats With Reduced Uterine Blood Flow
Preeclampsia is a leading cause of maternal and fetal morbidity/mortality; however, the pathophysiological mechanisms are unclear. Vascular endothelial dysfunction in preeclampsia has been partially attributed to changes in endothelin-1 (ET-1). Several enzymes, including matrix metalloproteinases (MMPs; particularly MMP-2), cleave the inactive precursor big ET-1 (bET-1) to active ET-1. Notably, expression levels of MMP-2 have been shown to be on the increase in women who subsequently develop preeclampsia. We hypothesized that the increased MMP-2 expression leads to increased bET-1 conversion, thereby increasing vasoconstriction in preeclampsia. A reduced uteroplacental perfusion pressure (RUPP) model of preeclampsia in the rat was used to assess mesenteric artery vascular function. Responses to bET-1 (3–310 nmol/L) and ET-1 (1–200 nmol/L) were studied in the presence or absence of inhibitors of enzymes known to cleave bET-1. Vascular contractility in response to bET-1 was greater in RUPP than Sham (P<0.001), whereas neither responses to ET-1 nor maximal contractility to high potassium salt solution (123.70 mmol/L) were different. MMP inhibition with GM6001 (30 μmol/L) significantly decreased responses to bET-1 in RUPP (P<0.001) but not Sham-operated rats. Interestingly, combined treatment with GM6001 and L-NG-nitroarginine methyl ester (100 μmol/L) revealed a NO modulation of MMPs that was reduced in RUPP. In summary, we found increased vascular contractility to bET-1 in the RUPP model of preeclampsia that was likely attributable to upstream enzymatic pathways. These data are consistent with a greater contribution of MMP to cleavage of bET-1 to ET-1 ex vivo in RUPP, suggesting that this enzyme may be partially responsible for increased bET-1–induced contractility.
- matrix metalloproteinases
- reduced uterine perfusion pressure
- vascular function
- Received August 20, 2012.
- Revision received December 7, 2012.
- Accepted December 10, 2012.
- © 2013 American Heart Association, Inc.