Actions of Esomeprazole on the Maternal Vasculature in Lean and Obese Pregnant Mice with Impaired Nitric Oxide Synthesis: A Model of Preeclampsia

Postpartum administration of eplerenone to mitigate vascular dysfunction in mice following a preeclampsia-like pregnancy

Preeclampsia is a severe pregnancy complication associated with substantial injury to systemic vasculature, major organs, and the feto-placental unit, with an approximate mortality rate of 76,000 pregnant women and 500,000 babies each year. Preeclampsia results in up to five-fold increased risk of cardiovascular disease. There is currently no cure and limited treatment options for preeclampsia and its long-term effects. In this study, we modelled preeclampsia in the mouse via nitric oxide blockade and examined the effect of therapeutic intervention during pregnancy (esomeprazole) and postpartum (eplerenone) on indices of cardiovascular health. Pregnant CBA x C57BL/6 mice received 50 mg/kg/day N(ω)-nitro-L-arginine methyl ester to induce a preeclampsia-like phenotype. Mice were treated with either 12.5 mg/kg/day esomeprazole during pregnancy, 55.5 mg/kg/day eplerenone during the postpartum period, or both esomeprazole and eplerenone in sequence. Mice were hypertensive during pregnancy, fetal growth was restricted by 10%, and maternal vasoactivity was impaired at 5-weeks postpartum. Eplerenone treatment (± esomeprazole) reduced vasoconstriction at 5-weeks postpartum and enhanced vasorelaxation at 5- and 10-weeks postpartum, supporting improved cardiovascular indices in the medium to long term postpartum period. Postpartum eplerenone treatment may be beneficial in mitigating consequent cardiovascular disease risk following a pregnancy complicated by preeclampsia.

Sulfasalazine for the treatment of preeclampsia in a nitric oxide synthase antagonist mouse model

INTRODUCTION

Development of a therapeutic that targets the pathophysiological elements of preeclampsia would be a major advance for obstetrics, with potential to save the lives of countless mothers and babies. We recently identified anti-inflammatory drug sulfasalazine as a prospective candidate therapeutic for treatment of preeclampsia. In primary human cells and tissues in vitro, sulfasalazine potently decreased secretion of anti-angiogenic sFlt-1 and sENG, increased production of pro-angiogenic PlGF, mitigated endothelial dysfunction, and promoted whole vessel vasodilation.

METHODS

Using nitric oxide synthase antagonist Nω-Nitro-l-arginine methyl ester hydrochloride, a preeclampsia-like phenotype was induced in pregnant mice, including high blood pressure, fetal growth restriction, and elevated circulating sFlt-1. Mice were treated with sulfasalazine or vehicle from gestational day (D)13.5, with blood pressure measurements across gestation, fetal measurements at D17.5, and wire myograph assessment of vasoactivity.

RESULTS

Sulfasalazine had a modest effect on blood pressure, decreasing diastolic and mean blood pressure on D13.5, but not later in gestation, or systolic blood pressure. Sulfasalazine was not able to rescue fetal growth, in male or female fetuses. There was a suggestion of improved vasoactivity with sulfasalazine, but further clarification is required.

DISCUSSION

In this mouse model of preeclampsia, sulfasalazine did not sustain reductions in blood pressure nor affect fetal parameters of size and weight, both desirable attributes of a viable preeclampsia therapeutic. While these data suggest sulfasalazine might improve vasoactivity, murine toxicity considerations limited the dose range of sulfasalazine that could be tested in the current study.

Proposal to Consider Chemical/Physical Microenvironment as a New Therapeutic Off-Target Approach

The molecular revolution could lead drug discovery from chance observation to the rational design of new classes of drugs that could simultaneously be more effective and less toxic. Unfortunately, we are witnessing some failure in this sense, and the causes of the crisis involve a wide range of epistemological and scientific aspects. In pharmacology, one key point is the crisis of the paradigm the “magic bullet”, which is to design therapies based on specific molecular targets. Drug repurposing is one of the proposed ways out of the crisis and is based on the off-target effects of known drugs. Here, we propose the microenvironment as the ideal place to direct the off-targeting of known drugs. While it has been extensively investigated in tumors, the generation of a harsh microenvironment is also a phenotype of the vast majority of chronic diseases. The hostile microenvironment, on the one hand, reduces the efficacy of both chemical and biological drugs; on the other hand, it dictates a sort of “Darwinian” selection of those cells armed to survive in such hostile conditions. This opens the way to the consideration of the microenvironment as a convenient target for pharmacological action, with a clear example in proton pump inhibitors.