Predictors of Impaired Postpartum Renal Function in Women after Preeclampsia: Results of a Prospective Single Center Study

Renal Function and the Role of the Renin-Angiotensin-Aldosterone System (RAAS) in Normal Pregnancy and Pre-Eclampsia

Objective: Pre-eclampsia (PE) is a complex, advancing condition marked either by the recent emergence of hypertension and proteinuria or by the recent onset of hypertension accompanied by notable end-organ impairment, which may occur with or without proteinuria. PE usually appears in the postpartum phase or after the 20th week of gestation, though it might appear sooner in cases of molar pregnancy. Pathophysiology: This disorder is a serious multisystem condition during pregnancy that can lead to serious, life-threatening complications for both the mother and the fetus if it is not diagnosed and managed promptly. These changes result from widespread and intense vasoconstriction caused by renin, angiotensin II (Ang II), aldosterone, and catecholamines. The renin-angiotensin-aldosterone system (RAAS) and its sequence of signaling reactions demonstrate its crucial role in regulating blood pressure and electrolyte balance that diverges in PE from that observed in healthy pregnancies. However, it is widely recognized that the above description is incomplete for pre-eclampsia and further relationships should be analyzed. The purpose of this article is to review and synthesize alterations in renal function and the RAAS during normal pregnancy and pre-eclampsia. We aim to provide clinical gynecologists with a comprehensive understanding of how pregnancy-specific adaptations can impact renal function and the RAAS, as well as the deviations observed in pre-eclampsia. Conclusion: This information is essential to enhance clinical awareness, improve the accuracy of diagnosis, and support evidence-based decision-making in the management of pregnant patients, especially those complicated by pre-eclampsia.

Maternal Microvascular Dysfunction During and After Preeclamptic Pregnancy

Preeclampsia, a pregnancy disorder characterized by de novo hypertension and maternal multisystem organ dysfunction, is the leading cause of maternal mortality worldwide and is associated with a fourfold greater risk of cardiovascular disease throughout the lifespan. Current understanding of the etiology of preeclampsia remains unclear, due in part to the varying phenotypical presentations of the disease, which has hindered the development of effective and mechanism-specific treatment or prevention strategies both during and after the affected pregnancy. These maternal sequelae of preeclampsia are symptoms of systemic vascular dysfunction in the maternal nonreproductive microvascular beds that drives the development and progression of adverse cardiovascular outcomes during preeclampsia. Despite normalization of vascular disturbances after delivery, subclinical dysfunction persists in the nonreproductive microvascular beds, contributing to an increased lifetime risk of cardiovascular and metabolic diseases and all-cause mortality. Given that women with a history of preeclampsia demonstrate vascular dysfunction despite an absence of traditional CVD risk factors, an understanding of the underlying mechanisms of microvascular dysfunction during and after preeclampsia is essential to identify potential therapeutic avenues to mitigate or reverse the development of overt disease. This article aims to provide a summary of the existing literature on the pathophysiology of maternal microvascular dysfunction during preeclampsia, the mechanisms underlying the residual dysfunction that remains after delivery, and current and potential treatments both during and after the affected pregnancy that may reduce microvascular dysfunction in these high-risk women. © 2024 American Physiological Society. Compr Physiol 14:5703-5727, 2024.

Temporal patterns of pre- and post-natal target organ damage associated with hypertensive pregnancy: a systematic review

AIMS

Hypertensive pregnancy is associated with increased risks of developing a range of vascular disorders in later life. Understanding when hypertensive target organ damage first emerges could guide optimal timing of preventive interventions. This review identifies evidence of hypertensive target organ damage across cardiac, vascular, cerebral, and renal systems at different time points from pregnancy to postpartum.

METHODS AND RESULTS

Systematic review of Ovid/MEDLINE, EMBASE, and ClinicalTrials.gov up to and including February 2023 including review of reference lists. Identified articles underwent evaluation via a synthesis without meta-analysis using a vote-counting approach based on direction of effect, regardless of statistical significance. Risk of bias was assessed for each outcome domain, and only higher quality studies were used for final analysis. From 7644 articles, 76 studies, including data from 1 742 698 pregnancies, were identified of high quality that reported either blood pressure trajectories or target organ damage during or after a hypertensive pregnancy. Left ventricular hypertrophy, white matter lesions, proteinuria, and retinal microvasculature changes were first evident in women during a hypertensive pregnancy. Cardiac, cerebral, and retinal changes were also reported in studies performed during the early and late post-partum period despite reduction in blood pressure early postpartum. Cognitive dysfunction was first reported late postpartum.

CONCLUSION

The majority of target organ damage reported during a hypertensive pregnancy remains evident throughout the early and late post-partum period despite variation in blood pressure. Early peri-partum strategies may be required to prevent or reverse target organ damage in women who have had a hypertensive pregnancy.

Long-term observational study of renal outcome after preeclampsia: Role of soluble fms-like tyrosine kinase-1(sFlt-1)/ placental growth factor (PlGF) and endoglin

Introduction

Preeclampsia (PE) is an important complication of pregnancy that can lead to chronic kidney disease. Soluble fms-like tyrosine kinase-1 (sFlt-1), placental growth factor (PlGF), the sFlt-1/PlGF ratio and endoglin are biomarkers for the differential diagnosis of PE and other diseases. We aimed to explore the correlation of these biomarkers with long-term renal function, blood pressure and the urine albumin/creatinine ratio (UACR) in PE patients.

Methods

34 patients with PE were enrolled. Blood samples for sFlt-1, PlGF, endoglin and the urine albumin/creatinine ratio (UACR) were collected at the time of PE diagnosis (at 35–40 weeks’ gestational age (GA) (87.50% of cases). After delivery, the patients were followed up at three months and one year to assess blood pressure, renal function and the UACR.

Results

Thirty-four PE patients were included, and 17 completed the study. The estimated glomerular filtration rate (eGFR) decreased significantly at three months and one year after follow-up (128.20 ± 10.34 to 120.75 ± 10.166 ml/min/1.73 m² (p = 0.001) at three months and 126.71 ± 9.948 to 114.29 ± 11.274 ml/min/1.73 m² (p < 0.001) at one year). The endoglin level correlated significantly with the eGFR level during PE, but there was no correlation of any biomarker with eGFR, blood pressure, or the UACR at one year.

Conclusion

Women with PE have a reduction of eGFR at three months and one year after the diagnosis of PE. Only endoglin is correlated with eGFR antepartum; however, it is not correlated with long-term renal function, blood pressure or the UACR.

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Preeclampsia has been suggested to increase the risk of kidney problems.

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The soluble endoglin level and sFlt-1:PlGF ratio can predict early and late-onset preeclampsia.

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Analysis of angiogenic factors may be associated with long term renal function.

Preeclampsia and eclampsia: the conceptual evolution of a syndrome

Preeclampsia, one of the most enigmatic complications of pregnancy, is considered a pregnancy-specific disorder caused by the placenta and cured only by delivery. This article traces the condition from its origins-once thought to be a disease of the central nervous system, recognized by the occurrence of seizures (ie, eclampsia)-to the present time when preeclampsia is conceptualized primarily as a vascular disorder. We review the epidemiologic data that led to the recommendation to use diastolic hypertension and proteinuria as diagnostic criteria, as their combined presence was associated with an increased risk of fetal death and the birth of small-for-gestational-age neonates. However, preeclampsia is a multisystemic disorder with protean manifestations, and the condition can be present even in the absence of hypertension and proteinuria. Toxins gaining access to the maternal circulation have been proposed to mediate the clinical manifestations-hence, the term "toxemia of pregnancy," which was used for several decades. The search for putative toxins has challenged investigators for more than a century, and a growing body of evidence suggests that products of an ischemic or a stressed placenta are responsible for the vascular changes that characterize this syndrome. The discovery that the placenta can produce antiangiogenic factors, which regulate endothelial cell function and induce intravascular inflammation, has been a major step forward in the understanding of preeclampsia. We view the release of antiangiogenic factors by the placenta as an adaptive response to improve uterine perfusion by modulating endothelial function and maternal cardiovascular performance. However, this homeostatic response can become maladaptive and lead to damage of target organs during pregnancy or the postpartum period. Early-onset preeclampsia has many features in common with atherosclerosis, whereas late-onset preeclampsia seems to result from a mismatch of fetal demands and maternal supply, that is, a metabolic crisis. Preeclampsia, as it is understood today, is essentially vascular dysfunction unmasked or caused by pregnancy. A subset of patients diagnosed with preeclampsia are at greater risk of the subsequent development of hypertension, ischemic heart disease, heart failure, vascular dementia, and end-stage renal disease. However, these adverse events may be the result of a preexisting vascular pathologic process; it is not known if the occurrence of preeclampsia increases the baseline risk. Therefore, the understanding, prediction, prevention, and treatment of preeclampsia are healthcare priorities.

PUM1 modulates trophoblast cell proliferation and migration through LRP6

Preeclampsia is a severe pregnancy complication characterized by hypertension and may cause maternal morbidity and mortality. A better understanding of the essential genes involved in preeclampsia pathophysiology is urgently needed. This study investigated the function and molecular mechanisms of pumilio RNA binding family member 1 (PUM1) in extravillous trophoblast cells (EVTs). The interaction between protein and mRNA was verified by RNA pull-down assays, RNA immunoprecipitation assays, and luciferase reporter assays. The mRNA and protein levels of the genes involved were determined by RT-qPCR and western blot assays, respectively. Our results demonstrated that PUM1 could bind to the 3'-untranslated region of low-density lipoprotein receptor-related protein 6 (LRP6) mRNA, resulting in reduced expression of LRP6 mRNA and protein. Repression of PUM1 resulted in enhanced colony formation, cell proliferation, migration, and invasion of EVTs. The PUM1-depletion-mediated promotion effects on EVTs could be abrogated by LRP6 knockdown. PUM1 regulates the growth and mobility of EVTs by modulating LRP6 expression. Developing strategies to balance PUM1 and LRP6 levels may be beneficial for the management of preeclampsia patients.

Role of sFlt-1/PIGF ratio and uterine Doppler in pregnancies with chronic kidney disease suspected with Pre-eclampsia or HELLP syndrome

PURPOSE

Pregnancies of women with chronic kidney disease (CKD) are at higher risk of experiencing adverse perinatal (APO) and maternal outcome (AMO). Mean uterine artery pulsatility index (mUtA-PI) as well as the ratio of soluble fms-like tyrosine kinase-1 (sFlt-1) and placental growth factor (PlGF) are helpful tools in diagnosing pre-eclampsia (PE) in women with CKD. The aim of the study was to evaluate the role of sFlt-1/PIGF ratio and mUtA-PI as predictors for APO, AMO, preterm delivery and decline of kidney function in CKD pregnancies.

METHODS

A total of 28 CKD pregnancies with suspected PE/HELLP syndrome were retrospectively included, in whom both sFlt-1/PIGF and mUtA-PI were determined during the third trimester. APO was defined as fetal growth restriction, respiratory distress syndrome, intubation, admission to NICU, 5 min Apgar <7 and intracerebral hemorrhage. AMO was defined as the development of PE, HELLP syndrome or resistant hypertension. Decline of kidney function was defined as a 25% increase of creatinine level after delivery.

RESULTS

Of all included women, eight (28.6%) developed a PE/HELLP syndrome. AMO (28.6%) and APO (32.1%) were frequently observed. ROC analyses revealed a predictive value for AMO and sFlt-1/PIGF or mUtA-PI. Neither sFlt-1/PIGF nor mUtA-PI could predict APO or decline of postnatal kidney function. mUtA-PI was a predictor for preterm delivery.

CONCLUSION

Uterine Doppler and sFlt-1/PIGF are predictors of AMO in CKD pregnancies. Therefore, both markers might be helpful for an improved risk assessment. However, neither sFlt-1/PIGF nor mUtA-PI were able to predict a decline of postnatal kidney function or APO.

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.

Downregulated low-density lipoprotein receptor-related protein 6 induces the maldevelopment of extravillous trophoblast via Wnt/β-catenin signaling pathway

Preeclampsia (PE), a special type of hypertensive disorder complicating pregnancy (HDCP), is highly associated with the migratory and invasive capacity of extravillous trophoblasts (EVTs). Here, we aimed to study the functions of low-density lipoprotein receptor-related protein 6 (LRP6) in PE pathogenesis. A comparative analysis of cellular gene expressions between placenta tissues collected from PE patients and normal pregnant women showed that the expressions of LRP6, β-catenin and matrix metallopeptidases/TIMP metallopeptidase inhibitors (MMPs/TIMPs) ratio in placentas of PE patients were much lower than the normal. Then, we constructed and transfected LRP6 siRNA (siLRP6) and LRP6 overexpression vectors into HTR6/SVneo cells. On the contrary to siLRP6, LRP6 overexpression could significant enhance cell viability, and strengthen the abilities of cell migration and invasion. Importantly, the overexpression of LRP6 could induce the upregulation of MMP-2 and MMP-9 levels, and downregulation of TIMPs. The mRNA and protein levels of β-catenin, an intracellular signal transducer of Wnt signaling pathway, were significantly up-regulated under the effects of LRP6 overexpression. XAV939, a Wnt/β-catenin pathway inhibitor, was introduced to confirm the involvement of Wnt/β-catenin pathway in functions of LRP6. The results of cell viability detection showed that XAV939 could significantly inhibit the positive effects of LRP6 overexpression on cell viability. Taken together, low-expressed LRP6 may be responsible of lower migration and invasion of EVTs and subsequent PE, and the mechanisms show a highly association with Wnt/β-catenin pathway.