Emerging drugs for preeclampsia--the endothelium as a target

Therapeutic restoration of female reproductive and endocrine dysfunction using stem cells

Millions of women worldwide suffer from infertility associated with gynecologic disorders such as premature ovarian insufficiency, polycystic ovary syndrome, Asherman syndrome, endometriosis, preeclampsia, and fallopian tube obstruction. These disorders can lead to infertility and thereby affect the quality of life of the infertile couple because of their psychological impact and significant costs. In recent years, stem cell therapy has emerged as a therapeutic approach to repair or replace damaged tissues or organs. This review describes the recent development as well as the underlying mechanisms of stem cell therapy for a variety of female reproductive diseases, offering us new therapeutic options for the treatment of female reproductive and endocrine dysfunction.

Shrunken pore syndrome in childhood cancer survivors treated with potentially nephrotoxic therapy

Childhood cancer survivors (CCS) are at risk of kidney dysfunction. Recently, the shrunken pore syndrome (SPS) has been described, which is characterized by selectively impaired filtration of larger molecules like cystatin C, while filtration of smaller molecules like creatinine is unaltered. It has been associated with increased mortality, even in the presence of a normal estimated glomerular filtration rate (eGFR). The aim of this study was to evaluate the prevalence of SPS in CCS exposed to potentially nephrotoxic therapy. In the Dutch Childhood Cancer Survivor Study (DCCSS)-LATER 2 Renal study, a nationwide cross-sectional cohort study, 1024 CCS ≥5 years after diagnosis, aged ≥18 years at study, treated between 1963-2001 with nephrectomy, abdominal radiotherapy, total body irradiation, cisplatin, carboplatin, ifosfamide, high-dose cyclophosphamide or hematopoietic stem cell transplantation participated, and 500 age- and sex-matched controls form Lifelines. SPS was defined as an eGFR_cys/eGFR_cr ratio <0.6 in the absence of non-GFR determinants of cystatin C and creatinine metabolism (i.e. hyperthyroidism, corticosteroids, underweight). Three pairs of eGFR-equations were used; CKD-EPI_cys/CKD-EPI_cr, CAPA/LMR, and FAS_cys/FAS_age. Median age was 32 years. Although an eGFR_cys/eGFR_cr ratio <0.6 was more common in CCS (1.0%) than controls (0%) based on the CKD-EPI equations, most cases were explained by non-GFR determinants. The prevalence of SPS in CCS was 0.3% (CKD-EPI equations), 0.2% (CAPA/LMR) and 0.1% (FAS equations), and not increased compared to controls. CCS treated with nephrotoxic therapy are not at increased risk for SPS compared to controls. Yet, non-GFR determinants are more common and should be taken into account when estimating GFR.

Preeclampsia beyond pregnancy: long-term consequences for mother and child

Preeclampsia is defined as new-onset hypertension after the 20th wk of gestation along with evidence of maternal organ failure. Rates of preeclampsia have steadily increased over the past 30 yr, affecting ∼4% of pregnancies in the United States and causing a high economic burden (22, 69). The pathogenesis is multifactorial, with acknowledged contributions by placental, vascular, renal, and immunological dysfunction. Treatment is limited, commonly using symptomatic management and/or early delivery of the fetus (6). Along with significant peripartum morbidity and mortality, current research continues to demonstrate that the consequences of preeclampsia extend far beyond preterm delivery. It has lasting effects for both mother and child, resulting in increased susceptibility to hypertension and chronic kidney disease (45, 54, 115, 116), yielding lifelong risk to both individuals. This review discusses recent guideline updates and recommendations along with current research on these long-term consequences of preeclampsia.

Low Birth Weight, Blood Pressure and Renal Susceptibility

PURPOSE OF THE REVIEW

The purpose of this review is to highlight the clinical significance of increased renal risk that has its origins in fetal life. This review will also discuss the critical need to identify therapeutic interventions for use in a pregnancy complicated by placental dysfunction and intrauterine growth restriction that can mitigate the developmental origins of kidney disease without inflicting additional harm on the developing fetus.

RECENT FINDINGS

A reduction in nephron number is a contributory factor in the pathogenesis of hypertension and kidney disease in low birth weight individuals. Reduced nephron number may heighten susceptibility to a secondary renal insult, and recent studies suggest that perinatal history including birth weight should be considered in the assessment of renal risk in kidney donors. This review highlights current findings related to placental dysfunction, intrauterine growth restriction, increased risk for renal injury and disease, and potential therapeutic interventions.

Superimposed Preeclampsia Exacerbates Postpartum Renal Injury Despite Lack of Long-Term Blood Pressure Difference in the Dahl Salt-Sensitive Rat

Preeclampsia results in increased susceptibility to hypertension and chronic kidney disease postpartum; however, the mechanisms responsible for disease progression in these women remain unknown. The purpose of this study was to test the hypothesis that 2 mechanisms contribute to the link between the maternal syndrome of preeclampsia and the increased postpartum risk of cardiovascular and renal disease: (1) increased T cells in the kidney and (2) a decreased NO:ET-1 (endothelin-1) ratio. Dahl S rats (a previously characterized model of preeclampsia superimposed on chronic hypertension) who experienced 2 pregnancies and virgin littermate controls were studied at 6 months of age. Mean arterial pressure was measured via telemetry, and renal injury was assessed through both histological analysis and measurement of urinary markers including nephrin, podocalyxin, and KIM-1 (kidney injury marker 1). Contributing mechanisms were assessed through flow cytometric analysis of renal T cells, quantification of plasma TNF-α (tumor necrosis factor-α) and IL-10 (interleukin-10), and quantification of urinary concentrations of NO metabolites and ET-1. Although prior pregnancy did not exacerbate the hypertension at 6 months, this group showed greater renal injury compared with virgin littermates. Flow cytometric analyses revealed an increase in renal T cells after pregnancy, and cytokine analysis revealed a systemic proinflammatory shift. Finally, the NO:ET-1 ratio was reduced. These results demonstrate that the link between the maternal syndrome of superimposed preeclampsia and postpartum risk of chronic kidney disease could involve both immune system activation and dysregulation of the NO:ET-1 balance.

Preeclampsia: Acute Complications and Management Priorities

Acute complications of preeclampsia contribute substantially to maternal and fetal morbidity and mortality. The considerable variation in onset, clinical presentation, and severity of this hypertensive disease that is unique to pregnancy creates challenges in identifying risk factors for clinical deterioration. Delivery of the fetus remains the only definitive treatment for preeclampsia. Surveillance of signs and symptoms and laboratory parameters consistent with progression in severity requires an appreciation of the dynamic and progressive nature of the disease. This article provides a comprehensive overview of the pathophysiology of preeclampsia, setting the foundation for discussion of management priorities for acute complications that pose the greatest risks to maternal health.

Pharmacogenetic relevance of endothelial nitric oxide synthase polymorphisms and gene interactions

Endothelial nitric oxide synthase (NOS3) is a key enzyme responsible for nitric oxide (NO) generation in the vascular endothelium. Endothelial dysfunction is characterized by reduced NO production, and is a hallmark of cardiovascular diseases. Drugs with cardiovascular action may activate NOS3 and result in NO release and vasodilation. Moreover, genetic variations affect NOS3 expression and activity, and may partially explain the variability in the responses to cardiovascular drugs. We reviewed NO signaling and genetic effects on NO formation, and the effects of NOS3 polymorphisms, haplotypes and gene-gene interactions within NO signaling pathways on the responses to cardiovascular drugs. We discuss the role of rare NOS3 variants and further gene-gene interactions analysis for the development of novel therapies for cardiovascular diseases.

Pravastatin for Preventing and Treating Preeclampsia: A Systematic Review

Importance

We have performed a systematic search to summarize the role of statins for preventing and treating severe preeclampsia.

Objective

The aim of this study was to examine whether pravastatin is a useful and safe alternative for treating preeclampsia during pregnancy.

Evidence Acquisition

A systematic MEDLINE (PubMed) search was performed (1979 to June 2017), which was restricted to articles published in English, using the relevant key words of "statins," "pregnancy," "preeclampsia," "obstetrical antiphospholipid syndrome," and "teratogenicity."

Results

The initial search provided 296 articles. Finally, 146 articles were related to the use of statins during pregnancy, regarding their effect on the fetus and the treatment of preeclampsia. Ten studies were related to in vitro studies, 25 in animals, and 24 in humans (13 case report series and 11 cohort studies). We found 84 studies on reviews of such guidelines on cardiovascular disease (35 studies), use of statins in the antiphospholipid syndrome (25 studies), statin's specific use during pregnancy (13 studies), or preeclampsia treatment (11 studies).

Conclusions

Although the studies are of poor quality, the rate of major congenital abnormalities in the newborn exposed to statins during pregnancy is no higher than the expected when compared with overall risk population. The review shows a potential beneficial role of statins in preventing and treating severe preeclampsia that needs to be evaluated through well-designed clinical trials.

Relevance

This update could influence positively the clinical practice, giving an alternative therapy for clinicians who treat preeclampsia, particularly in severe cases.

Phosphodiesterase Inhibition in the Treatment of Preeclampsia: What Is New?

PURPOSE OF REVIEW

The present study intends to review the possibility of using phosphodiesterase inhibitors as a treatment option for preeclampsia, addressing potential risks and benefits.

RECENT FINDINGS

Preeclampsia is the most common hypertensive disorder of pregnancy, often responsible for severe maternal and fetal complications, which can lead to early pregnancy termination and death. Despite the numerous studies, its pathophysiology is still unclear, although it seems to involve a multiplicity of complex factors related to angiogenesis, ineffective vasodilation, oxidative stress, inflammatory cytokines, and endothelial dysfunction. It has been hypothetically suggested that the use of phosphodiesterase inhibitors is capable of improving placental and fetal perfusion, contributing to gestational scenario, by decreasing the symptomatology and severity of this syndrome. In this literature review, it has been found that most of the studies were conducted in animal models, and there is still lack of evidence supporting its use in clinical practice. Research in human indicates conflicting findings; randomized controlled trials were scarce and did not demonstrate any benefit in morbidity or mortality. Data regarding to pathophysiological and interventional research are described and commented in this review. The use of phosphodiesterase inhibitors in the treatment of preeclampsia is controversial and should not be encouraged taking into account recent data.

The effects of sildenafil citrate on uterine angiogenic status and serum inflammatory markers in an L-NAME rat model of pre-eclampsia

Pre-eclampsia (PE), a hypertensive disorder of pregnancy, is detrimental to both mother and foetus. There is currently no effective treatment, but we have shown that Sildenafil Citrate (SC) improve various foetal outcomes in N^ω-nitro-L arginine methyl ester (L-NAME) rat model of PE. Therefore, we aimed to investigate the effects of SC on a uterine angiogenic status and serum inflammatory markers in an L-NAME rat model of PE. One hundred and twenty adult nulliparous pregnant female Sprague-Dawley rats were used for the study. These were divided into five equal groups; the pregnant control, early and late onset PE and respective SC treated animals. Hypertension was manifested by considerably increased systolic blood pressure and placental lipid peroxidative marker (thiobarbituric acid reactive substances) and also we assessed the activities of plasma nitric oxide level, serum inflammatory marker (TGF-β and IFN-γ) and uterine angiogenic status (VEGF and sFlt-1) at two stages of PE. The administration of SC decreased systolic blood pressure, placental lipid peroxidation product and altered uterine angiogenic status; increased plasma nitric oxide levels in an early and late onset L-NAME model of PE. In addition, histological findings of SC treated preeclamptic rat placenta support the biochemical findings of this study. Our findings revealed that SC enhanced plasma NO levels and uterine angiogenic status in an L-NAME model of PE at two gestational stages.

The enigma of continual plasma volume expansion in pregnancy: critical role of the renin-angiotensin-aldosterone system

Pregnancy is characterized by avid renal sodium retention and plasma volume expansion in the presence of decreased blood pressure. Decreased maternal blood pressure is a consequence of reduced systemic vascular tone, which results from an increased production of vasodilators [nitric oxide (NO), prostaglandins, and relaxin] and decreased vascular responsiveness to the potent vasoconstrictor (angiotensin II). The kidneys participate in this vasodilatory response, resulting in marked increases in renal plasma flow and glomerular filtration rate (GFR) during pregnancy. In women, sodium retention drives plasma volume expansion (∼40%) and is necessary for perfusion of the growing uterus and fetus. For there to be avid sodium retention in the presence of the potent natriuretic influences of increased NO and elevated GFR, there must be modifications of the tubules to prevent salt wasting. The purpose of this review is to summarize these adaptations.

Shrunken Pore Syndrome is associated with a sharp rise in mortality in patients undergoing elective coronary artery bypass grafting

Shrunken Pore Syndrome was recently suggested for the pathophysiologic state in patients characterized by an estimation of their glomerular filtration rate (GFR) based upon cystatin  C, which is lower or equal to 60% of their estimated GFR based upon creatinine, i.e. when eGFR_{cystatin  C} ≤ 60% of eGFR_creatinine. Not only the cystatin  C level, but also the levels of other low molecular mass proteins are increased in this condition. The preoperative plasma levels of cystatin  C and creatinine were measured in 1638 patients undergoing elective coronary artery bypass grafting. eGFR_{cystatin  C} and eGFR_creatinine were calculated using two pairs of estimating equations, CAPA and LMrev, and CKD-EPI_{cystatin  C} and CKD-EPI_creatinine, respectively. The Shrunken Pore Syndrome was present in 2.1% of the patients as defined by the CAPA and LMrev equations and in 5.7% of the patients as defined by the CKD-EPI_{cystatin  C} and CKD-EPI_creatinine equations. The patients were studied over a median follow-up time of 3.5 years (2.0–5.0 years) and the mortality determined. Shrunken Pore Syndrome defined by both pairs of equations was a strong, independent, predictor of long-term mortality as evaluated by Cox analysis and as illustrated by Kaplan-Meier curves. Increased mortality was observed also for the subgroups of patients with GFR above or below 60 mL/min/1.73 m². Changing the cut-off level from 60 to 70% for the CAPA and LMrev equations increased the number of patients with Shrunken Pore Syndrome to 6.5%, still displaying increased mortality.

G-Protein-coupled receptors as potential drug candidates in preeclampsia: targeting the relaxin/insulin-like family peptide receptor 1 for treatment and prevention

BACKGROUND

Important roles for G-protein-coupled receptors (GPCRs) have been identified in the maternal physiological adaptations to pregnancy and in the pathogenesis of preeclampsia. On this basis, GPCRs are potential therapeutic targets for preeclampsia.

OBJECTIVES AND RATIONALE

In this review, vasopressin and apelin are initially considered in this context before the focus on the hormone relaxin and its cognate receptor, the relaxin/insulin-like family peptide receptor 1 (RXFP1). Based on both compelling scientific rationale and a promising safety profile, the relaxin ligand-receptor system is comprehensively evaluated as a potential therapeutic endpoint in preeclampsia.

SEARCH METHODS

The published literature relating to the topic was searched through January 2016 using PubMed.

OUTCOMES

Relaxin is a peptide hormone secreted by the corpus luteum; it circulates in the luteal phase and during pregnancy. Activation of RXFP1 is vasodilatory; thus, relaxin supplementation is expected to at least partly restore the fundamental vasodilatory changes of normal pregnancy, thereby alleviating maternal organ hypoperfusion, which is a major pathogenic manifestation of severe preeclampsia. Specifically, by exploiting its pleiotropic hemodynamic attributes in preeclampsia, relaxin administration is predicted to (i) reverse robust arterial myogenic constriction; (ii) blunt systemic and renal vasoconstriction in response to activation of the angiotensin II receptor, type 1; (iii) mollify the action of endogenous vasoconstrictors on uterine spiral arteries with failed remodeling and retained smooth muscle; (iv) increase arterial compliance; (v) enhance insulin-mediated glucose disposal by promoting skeletal muscle vasodilation and (vi) mobilize and activate bone marrow-derived angiogenic progenitor cells, thereby repairing injured endothelium and improving maternal vascularity in organs such as breast, uterus, pancreas, skin and fat. By exploiting its pleiotropic molecular attributes in preeclampsia, relaxin supplementation is expected to (i) enhance endothelial nitric oxide synthesis and bioactivity, as well as directly reduce vascular smooth muscle cytosolic calcium, thus promoting vasodilation; (ii) improve the local angiogenic balance by augmenting arterial vascular endothelial and placental growth factor (VEGF and PLGF) activities; (iii) ameliorate vascular inflammation; (iv) enhance placental peroxisome proliferator-activated receptor gamma, coactivator 1 alpha (PCG1α) expression, and hence, peroxisome proliferator-activated receptor gamma (PPAR-γ) activity and (v) confer cytotrophoblast and endothelial cytoprotection. Insofar as impaired endometrial maturation (decidualization) predisposes to the development of preeclampsia, relaxin administration in the late secretory phase and during early pregnancy would be anticipated to improve decidualization, and hence trophoblast invasion and spiral artery remodeling, thereby reducing the risk of preeclampsia. Relaxin has a favorable safety profile both in the non-pregnant condition and during pregnancy.

WIDER IMPLICATIONS

There is a strong scientific rationale for RXFP1 activation in severe preeclampsia by administration of relaxin, relaxin analogs or small molecule mimetics, in order to mollify the disease pathogenesis for safe prolongation of pregnancy, thus allowing time for more complete fetal maturation, which is a primary therapeutic endpoint in treating the disease. In light of recent data implicating deficient or defective decidualization as a potential etiological factor in preeclampsia and the capacity of relaxin to promote endometrial maturation, the prophylactic application of relaxin to reduce the risk of preeclampsia is a plausible therapeutic approach to consider. Finally, given its pleiotropic and beneficial attributes particularly in the cardiovascular system, relaxin, although traditionally considered as a 'pregnancy' hormone, is likely to prove salutary for several disease indications in the non-pregnant population.

Dual inhibition of renin-angiotensin-aldosterone system and endothelin-1 in treatment of chronic kidney disease

Inhibition of the renin-angiotensin-aldosterone system (RAAS) plays a pivotal role in treatment of chronic kidney diseases (CKD). However, reversal of the course of CKD or at least long-term stabilization of renal function are often difficult to achieve, and many patients still progress to end-stage renal disease. New treatments are needed to enhance protective actions of RAAS inhibitors (RAASis), such as angiotensin-converting enzyme (ACE) inhibitors (ACEIs) or angiotensin receptor blockers (ARBs), and improve prognosis in CKD patients. Inhibition of endothelin (ET) system in combination with established RAASis may represent such an approach. There are complex interactions between both systems and similarities in their renal physiological and pathophysiological actions that provide theoretical rationale for combined inhibition. This view is supported by some experimental studies in models of both diabetic and nondiabetic CKD showing that a combination of RAASis with ET receptor antagonists (ERAs) ameliorate proteinuria, renal structural changes, and molecular markers of glomerulosclerosis, renal fibrosis, or inflammation more effectively than RAASis or ERAs alone. Practically all clinical studies exploring the effects of RAASis and ERAs combination in nephroprotection have thus far applied add-on designs, in which an ERA is added to baseline treatment with ACEIs or ARBs. These studies, conducted mostly in patients with diabetic nephropathy, have shown that ERAs effectively reduce residual proteinuria in patients with baseline RAASis treatment. Long-term studies are currently being conducted to determine whether promising antiproteinuric effects of the dual blockade will be translated in long-term nephroprotection with acceptable safety profile.

Sildenafil Treatment Ameliorates the Maternal Syndrome of Preeclampsia and Rescues Fetal Growth in the Dahl Salt-Sensitive Rat

Preeclampsia, a hypertensive disorder of pregnancy, is detrimental to both mother and fetus. There is currently no effective treatment, but sildenafil, a phosphodiesterase-5 inhibitor, has been proposed as a potential therapy to reduce blood pressure and improve uteroplacental perfusion in preeclamptic patients. We hypothesized that sildenafil would improve the maternal syndrome and fetal outcomes in the Dahl S rat model of superimposed preeclampsia. Dahl S rats were mated, and half received sildenafil (50 mg/kg per day, via food) from day 10 through day 20 of pregnancy. The untreated Dahl S rats had a significant rise in blood pressure and a 2-fold increase in urinary protein excretion from baseline to late pregnancy; however, sildenafil-treated Dahl S rats exhibited ≈40 mm Hg drops in blood pressure with no rise in protein excretion. Sildenafil also increased creatinine clearance and reduced nephrinuria and glomerulomegaly. Sildenafil treatment reduced the uterine artery resistance index during late pregnancy in the Dahl S rat and improved fetal outcomes (survival, weight, and litter size). In addition, 19% of all pups were resorbed in untreated rats, with no incidence of resorptions observed in the treated group. Furthermore, tumor necrosis factor-α, endothelin-1, and oxidative stress, which are characteristically increased in women with preeclampsia and in experimental models of the disease, were reduced in treated rats. These data suggest that sildenafil improves the maternal syndrome of preeclampsia and blood flow to the fetoplacental unit, providing preclinical evidence to support the hypothesis that phosphodiesterase type 5 inhibition may be an important therapeutic target for the treatment of preeclampsia.