Reductions of Circulating Nitric Oxide are Followed by Hypertension during Pregnancy and Increased Activity of Matrix Metalloproteinases-2 and -9 in Rats.

Hypertensive pregnancy has been associated with reduced nitric oxide (NO), bioavailability, and increased activity of matrix metalloproteinases (MMPs). However, it is unclear if MMPs activation is regulated by NO during pregnancy. To this end, we examined activity of MMP-2 and MMP-9 in plasma, placenta, uterus and aorta, NO bioavailability, oxidative stress, systolic blood pressure (SBP), and fetal-placental development at the early, middle, and late pregnancy stages in normotensive and Nω-Nitro-L-arginine methyl-ester (L-NAME)-induced hypertensive pregnancy in rats.

Hypertension, augmented activity of matrix metalloproteinases-2 and -9 and angiogenic imbalance in hypertensive pregnancy are attenuated by doxycycline.

Preeclampsia is manifested as maternal hypertension and fetal growth restriction. Matrix metalloproteinases (MMPs) are involved in hypertension and doxycycline reduces blood pressure by inhibition of MMPs. Moreover, excessive levels of MMPs and reduced nitric oxide (NO) bioavailability have been related to preeclampsia.

Clinical and Experimental Evidences of Hydrogen Sulfide Involvement in Lead-Induced Hypertension.

Lead- (Pb-) induced hypertension has been shown in humans and experimental animals and cardiovascular effects of hydrogen sulfide (HS) have been reported previously. However, no studies examined involvement of HS in Pb-induced hypertension. We found increases in diastolic blood pressure and mean blood pressure in Pb-intoxicated humans followed by diminished HS plasmatic levels.

Maternal hypertension and feto-placental growth restriction is reversed by sildenafil: Evidence of independent effects of circulating nitric oxide levels.

Sildenafil has shown nitric oxide (NO)-independent pleiotropic effects, however the mechanisms involved are unclear. We investigated the protective effects of sildenafil against hypertension in pregnancy and feto-placental growth restriction induced by NO inhibition, and if sodium nitrite-derived NO formation influences sildenafil effects. We evaluated the plasmatic levels of NO metabolites, cyclic guanosine monophosphate (cGMP), oxidative stress and myeloperoxidase, which are involved in endothelial dysfunction during hypertension in pregnancy.

Cardiac myeloperoxidase activity is elevated in hypertensive pregnant rats.

Myeloperoxidase (MPO) is released from activated neutrophils. The inflammation in preeclampsia was found to be associated with endothelial dysfunction. We hypothesized that cardiac and circulating MPO levels are elevated in hypertensive pregnancy.

Sodium hydrosulfide prevents hypertension and increases in vascular endothelial growth factor and soluble fms-like tyrosine kinase-1 in hypertensive pregnant rats.

Sodium hydrosulfide (NaHS) has presented antihypertensive and antioxidant effects and may reduce circulating soluble fms-like tyrosine kinase-1 (sFlt-1). We examined whether NaHS prevents maternal and fetal detrimental changes in a model of hypertension in pregnancy induced by N(G)-nitro-L-arginine methyl ester (L-NAME). Forty pregnant rats were divided into four groups (n = 10 per group): Norm-Preg, Preg + NaHS, HTN-Preg, or HTN-Preg + NaHS.

Sodium nitrite attenuates hypertension-in-pregnancy and blunts increases in soluble fms-like tyrosine kinase-1 and in vascular endothelial growth factor.

Preeclampsia is a pregnancy-associated disorder characterized by hypertension with uncertain pathogenesis. Increases in antiangiogenic soluble fms-like tyrosine kinase-1 (sFlt-1) and reductions in nitric oxide (NO) bioavailability have been observed in preeclamptic women. However, the specific mechanisms linking these detrimental changes to the hypertension-in-pregnancy are not clearly understood.

Exposure to fipronil elevates systolic blood pressure and disturbs related biomarkers in plasma of rats.

Recent reports show that fipronil affects non-target organisms, including environmental species populations and potentially humans. We aimed to examine if fipronil exposure affects the systolic blood pressure and related biomarkers. Thus, fipronil was orally administered to rats (30 mg/kg/day) during 15 days (Fipronil group) or physiological solution (Control group).

Sodium Nitrite Prevents both Reductions in Circulating Nitric Oxide and Hypertension in 7-Day Lead-Treated Rats.

Hypotensive effects of oral sodium nitrite have been reported as alternative sources of nitric oxide (NO) formation in animals and human beings. Reductions in NO bioavailability were observed in lead-induced hypertension. However, no previous study has examined whether a single daily dose of sodium nitrite prevents the reductions in the NO bioavailability in lead-induced hypertension.

Metalloproteinase Inhibition Protects against Reductions in Circulating Adrenomedullin during Lead-induced Acute Hypertension.

Intoxication with lead (Pb) results in increased blood pressure by mechanisms involving matrix metalloproteinases (MMPs). Recent findings have revealed that MMP type two (MMP-2) seems to cleave vasoactive peptides. This study examined whether MMP-2 and MMP-9 levels/activities increase after acute intoxication with low lead concentrations and whether these changes were associated with increases in blood pressure and circulating endothelin-1 or with reductions in circulating adrenomedullin and calcitonin gene-related peptide (CGRP).