High first-trimester maternal blood cystatin C levels despite normal serum creatinine predict pre-eclampsia in singleton pregnancies

Potential urinary biomarkers in preeclampsia: a narrative review

INTRODUCTION

Preeclampsia (PE) is a highly relevant pregnancy-related disorder. An early and accurate diagnosis is crucial to prevent major maternal and neonatal complications and mortality. Due to the association of kidney dysfunction with the pathophysiology of the disease, urine samples have the potential to provide biomarkers for PE prediction, being minimally invasive and easy to perform. Therefore, searching for novel biomarkers may improve outcomes. This narrative review aimed to summarize the scientific literature about the traditional and potential urinary biomarkers in PE and to investigate their applicability to screen and diagnose the disorder.

METHODS

A non-systematic search was performed in PubMed/MEDLINE, Scopus, and SciELO databases.

RESULTS

There is significant divergence in the literature regarding traditionally used serum markers creatinine, cystatin C, and albuminuria, accuracy in PE prediction. As for the potential renal biomarkers investigated, including vascular epithelial growth factor (VEGF), placental growth factor (PlGF), and soluble fms-like tyrosine kinase (sFlt-1), urinary levels of PlGF and sFtl-1/PlGF ratio in urine seem to be the most promising as screening tests. The assessment of the global load of misfolded proteins through urinary congophilia, podocyturia, and nephrinuria has also shown potential for screening and diagnosis. Studies regarding the use of proteomics and metabolomics have shown good accuracy, sensitivity, and specificity for predicting the development and severity of PE.

CONCLUSION

However, there are still many divergences in the literature, which requires future and more conclusive research to confirm the predictive role of urinary biomarkers in pregnant women with PE.

Diagnostic biomolecules and combination therapy for pre-eclampsia

Pre-eclampsia (PE), associated with placental malperfusion, is the primary reason for maternal and perinatal mortality and morbidity that can cause vascular endothelial injury and multi-organ injury. Despite considerable research efforts, no pharmaceutical has been shown to stop disease progression. If women precisely diagnosed with PE can achieve treatment at early gestation, the maternal and fetal outcomes can be maximally optimized by expectant management. Current diagnostic approaches applying maternal characteristics or biophysical markers, including blood test, urine analysis and biophysical profile, possess limitations in the precise diagnosis of PE. Biochemical factor research associated with PE development has generated ambitious diagnostic targets based on PE pathogenesis and dissecting molecular phenotypes. This review focuses on current developments in biochemical prediction of PE and the corresponding interventions to ameliorate disease progression, aiming to provide references for clinical diagnoses and treatments.

Shrunken Pore Syndrome Is Associated with Renal Function Decline in Female Patients with Kidney Diseases

Background

Shrunken pore syndrome (SPS) represents selective impairment of kidney filtration of low-molecular-weight molecules between 1 and 30 kDa and has been related to outcomes including morbidity, mortality, and cardiovascular events. However, the prevalence and kidney outcomes of SPS have not been investigated in patients with IgA nephropathy (IgAN) and membranous nephropathy (MN).

Methods

We retrospectively collected information of 536 patients including 414 with IgAN and 122 with MN. SPS was mainly defined by cystatin C-based eGFR < 70% of creatinine-based eGFR using the CAPA-LM equation pairs, while CKD-EPI equations were also employed in sensitivity analyses. Prevalence rate of SPS and its association with end-stage renal disease (ESRD) or severe eGFR decline (≥50% eGFR reduction or doubling of baseline creatinine) were investigated.

Results

44% (8%) patients were identified as possessing SPS using the CAPA-LM definition. ESRD happened in 24 patients during the average follow-up period of 27.7 months. Despite dramatic increase of incidence rate of ESRD for SPS, significant hazard ratio (HR) only existed in IgAN patients after multivariable adjustment (HR: 8.35, 95% CI: 2.10~33.26), but lost significance in sensitivity analyses. 36 patients were determined as having experienced severe eGFR decline after excluding transient creatinine fluctuation. SPS was associated with severe eGFR decline by Kaplan-Meier survival analyses in the overall population as well as the IgAN, MN, male, and female subpopulations, which remained significant in multivariable adjustments in all groups except IgAN. However, only in female patients the association between SPS and eGFR decline remained significant in all the sensitivity analyses.

Conclusions

SPS was independently associated with eGFR decline in female patients with IgAN and MN.

Association of gestational hypertension and preeclampsia with nonsyndromic orofacial clefts in China: a large prospective cohort study

BACKGROUND

The associations between hypertensive disorders of pregnancy and nonsyndromic orofacial clefts (NSOFCs) are not consistent or based on case-control study design. We hypothesize that OFCs and NSOFCs are associated with hypertensive disease in pregnancy.

METHODS

Data were collected from the Project for Neural Tube Defects Prevention (1993-1996), a large population-based cohort study conducted in two southern provinces of China. We used a system to record all births after 20 complete gestational weeks, including live births and stillbirths, and all structural congenital anomalies regardless of gestational week. A total of 200 215 singleton live births without other external birth defects were finally included.

RESULTS

The incidence of NSOFCs was 20.2 per 10 000 for the whole population, and 20.5 and 39.2 per 10 000 for women with gestational hypertension and preeclampsia, respectively. Compared with the nonpreeclampsia group, preeclampsia was associated with an increased risk of NSOFCs [adjusted risk ratio (RR) = 2.02, 95% confidence interval (CI): 1.27-3.20], cleft lip with or without cleft palate (CL/P) [adjusted RR = 2.24, 95% CI 1.37-3.65], and cleft lip and palate (CLP) [adjusted RR = 2.60, 95% CI 1.45-4.67] but not cleft lip only (CLO) [adjusted RR = 1.66, 95% CI 0.68-4.07] or cleft palate only (CPO) [adjusted RR = 1.09, 95% CI 0.27-4.45]. No associations were observed between gestational hypertension and any types of NSOFCs.

CONCLUSION

Our study supported that among hypertensive disorders of pregnancy, only preeclampsia increased the risk of NSOFCs and its subtypes (CL/P and CLP).

Trimester-specific reference intervals for cystatin C and neutrophil gelatinase-associated lipocalin during pregnancy

BACKGROUND

During normal pregnancy, the glomerular filtration rate (GFR) increases dramatically. Failure to obtain this physiological increase is an important risk factor for morbidity and mortality for both mother and child. The estimated GFR (eGFR) using serum creatinine levels is unsuitable for accurate measurement of renal function during pregnancy. Therefore, new biomarkers have been proposed. Elevated levels of Cystatin C (CysC) and Neutrophil Gelatinase-Associated Lipocalin (NGAL) are associated with renal failure and preeclampsia (PE). In this study, we determined reference intervals for CysC and NGAL during pregnancy.

METHODS

Healthy pregnant women were recruited and blood samples were collected at 9-13 weeks (T1), 27-29 weeks (T2), and 36-39 weeks (T3) of gestation and at 4-13 weeks postpartum (PP). The samples from women with uncomplicated pregnancy were analyzed to determine median values and upper reference limits (URLs, 97.5 percentiles) of creatinine, CysC, and NGAL.

RESULTS

A total of 175 women were included. Longitudinal changes and median values of creatinine, CysC, and NGAL were determined using only complete data sets (n=59). URLs were determined using all available data. The URL at T1, T2, T3, and PP were 60, 63, 74, 93 μmol/L for creatinine; 0.93, 1.04, 1.61, 1.23 mg/L for CysC; and 87, 84, 88, 95 ng/mL for NGAL.

CONCLUSIONS

CysC concentrations are highly dynamic and increase during pregnancy. NGAL concentrations are less dynamic, but well below the URL specified by the manufacturer for non-pregnant women. It is therefore recommended to use trimester-specific reference values for both CysC and NGAL.

Association of Maternal Serum Uric Acid and Cystatin C Levels in Late Pregnancy with Adverse Birth Outcomes: An Observational Cohort Study in China

Objective

To investigate the associations between serum uric acid (UA) and cystatin C (CysC) levels in late pregnancy with major unfavorable birth outcomes.

Methods

We retrospectively analyzed the maternal UA and CysC levels during late pregnancy and their relationship with unfavorable birth outcomes in a Chinese population (n = 11,580).

Results

Women with the highest quartile of UA had higher risks of low birth weight (LBW) and small for gestational age (SGA) babies and a lower risk of preterm birth (PTB) compared to women with the lowest quartile [for LBW, adjusted-odds ratio (OR) = 2.63, 95% CI: 1.76, 3.95; for SGA, adjusted-OR = 2.11, 95% CI: 1.73, 2.57; for PTB, adjusted-OR = 0.55, 95% CI: 0.45, 0.69; all P for trend <0.001]. Compared to women in the lowest quartile of CysC, higher risks of macrosomia and large for gestational age (LGA) and lower risks of PTB and SGA were observed for those in the highest quartile (for macrosomia, adjusted-OR = 2.01, 95% CI: 1.60, 2.51; for LGA, adjusted-OR = 1.97, 95% CI: 1.67, 2.32; for PTB, adjusted-OR = 0.32, 95% CI: 0.26, 0.41; all P for trend <0.001; for SGA, adjusted-OR = 0.78, 95% CI: 0.64, 0.96; P for trend <0.05).

Conclusion

This study reports the associations of maternal UA and CysC with adverse birth outcomes, and suggests that routine determination of maternal UA and CysC in late pregnancy is beneficial for assessing the risks of these outcomes.

A Review of Specific Biomarkers of Chronic Renal Injury and Their Potential Application in Nonclinical Safety Assessment Studies

A host of novel renal biomarkers have been developed over the past few decades which have enhanced monitoring of renal disease and drug-induced kidney injury in both preclinical studies and in humans. Since chronic kidney disease (CKD) and acute kidney injury (AKI) share similar underlying mechanisms and the tubulointerstitial compartment has a functional role in the progression of CKD, urinary biomarkers of AKI may provide predictive information in chronic renal disease. Numerous studies have explored whether the recent AKI biomarkers could improve upon the standard clinical biomarkers, estimated glomerular filtration rate (eGFR), and urinary albumin to creatinine ratio, for predicting outcomes in CKD patients. This review is an introduction to alternative assays that can be utilized in chronic (>3 months duration) nonclinical safety studies to provide information on renal dysfunction and to demonstrate specific situations where these assays could be utilized in nonclinical drug development. Novel biomarkers such as symmetrical dimethyl arginine, dickkopf homolog 3, and cystatin C predict chronic renal injury in animals, act as surrogates for GFR, and may predict changes in GFR in patients over time, ultimately providing a bridge from preclinical to clinical renal monitoring.

Cystatin C as a biomarker of chronic kidney disease: latest developments

INTRODUCTION

Chronic kidney disease (CKD) is common, occurring in over 10% of individuals globally, and is increasing in prevalence. The limitations of traditional biomarkers of renal dysfunction, such as serum creatinine, have been well demonstrated in the literature. Therefore, augmenting clinical assessment with newer biomarkers, such as serum cystatin C, has the potential to improve disease monitoring and patient care.

AREAS COVERED

The present paper assesses the utility and limitations of serum cystatin C as a biomarker for CKD in light of the current literature.

EXPERT OPINION

Serum cystatin C has been well established as an early and accurate biomarker of CKD that is particularly helpful in patients for whom creatinine is an inadequate marker or for whom more cumbersome methods of glomerular filtration rate (GFR) measurement are impractical. Current research questions are no longer focused on if, but rather when and how often cystatin C should be used in the evaluation of CKD patients. However, transition of all reagents and estimated GFR equations to the newly established International Standard is critical for developing generalizable data.

Serum cystatin-c as predictive factor of preeclampsia: A meta-analysis of 27 observational studies

OBJECTIVE

Serum cystatin-c is a protein that is filtered freely through the glomerulus and reabsorbed and degraded by proximal tubular cells and can be used as a biomarker of renal function. Its levels rise during the third trimester and decrease in the postpartum period. The purpose of the present meta-analysis is to assess the performance of serum cystatin-c for the prediction of preeclampsia.

DESIGN AND METHODS

We used the Medline, Scopus, Clinicaltrials.gov, EMBASE, Cochrane Central Register of Controlled Trials CENTRAL and Google Scholar. We selected all observational studies (both prospective and retrospective) that investigated the accuracy of cystatin-c in predicting preeclampsia. Statistical meta-analysis was performed with the RevMan 5.3 and Stata/IC 13.0 software, using hierarchical models to develop the SROC curve.

RESULTS

The quantitative synthesis was based in 27 studies with a total number of 2,320 women. Serum cystatin-c levels were higher in preeclamptic women compared to healthy pregnant controls (MD: 0.40 mg/l, 95% CI [0.33, 0.46]). The pooled sensitivity of serum cystatin-c for the prediction of preeclampsia was 0.85 (95% CI [0.79-0.89]) and the pooled specificity 0.84 (95% CI [0.77-0.90]. Fagan's nomogram indicated that the post-test probability increased to 14% (positive test) and decreased to 1% (negative test), when the pre-test probability was set at 3%.

CONCLUSIONS

According to the findings of our study serum cystatin-c seems to be a promising biomarker for the detection of preeclampsia during the third trimester of pregnancy. Therefore, its implementation in future predictive models in the field is recommended.

Clinical Pharmacology and Pharmacometrics to Better Understand Physiological Changes During Pregnancy and Neonatal Life

Pregnant women, fetuses, and newborns are particularly vulnerable patient populations. During pregnancy, the body is subject to physiological changes that influence the pharmacokinetics and pharmacodynamics of drugs. Inappropriate dosing in pregnant women can result in sub-therapeutic or toxic effects, putting not only the pregnant woman but also her fetus at risk. During neonatal life, maturation processes also affect pharmacokinetics and pharmacodynamics of drugs. Inappropriate dosing in newborns leads not only to short-term complications but can also have a negative impact on the long-term development of infants and children. For these reasons, it is crucial to characterize physiological changes in pregnant women, describe placental transfer kinetics of drugs, and describe physiological changes related to the transition from intrauterine to extrauterine life and maturation processes in preterm and term neonates. Quantitative pharmacological approaches such as pharmacometric and physiologically-based modeling and model-based simulations can be useful to better understand and predict such physiological changes and their effects on drug exposure and response. This review article (1) gives an overview of physiological changes in pregnant women, their fetuses, and (pre)term neonates, (2) presents case studies to illustrate applications of new modeling and simulation approaches, and (3) discusses challenges and opportunities in optimizing and personalizing treatments during pregnancy and neonatal life.

Relationship of Postpartum Levels of Cystatin and High-Sensitivity C-Reactive Protein and Duration of Lactation in Mothers with Previous Gestational Hypertension or Preeclampsia

Background: Women with hypertensive disorders of pregnancy are at increased risk of cardiovascular disease in later life. We sought to determine the association between lactation and markers of maternal cardiovascular health among postpartum women with and without hypertensive disorders of pregnancy via measures of inflammation (high-sensitivity C-reactive protein [hsCRP]) and renal function (cystatin C). Materials and Methods: This prospective cohort study enrolled primarily overweight and obese women during early pregnancy. At a postpartum study visit occurring 6-24 months after delivery, we collected data on lactation duration and measured hsCRP and cystatin C. We assessed associations between lactation duration and levels of hsCRP and cystatin C among normotensive women and women with preeclampsia or gestational hypertension using analysis of variance and chi-squared tests. Linear regression models adjusted for age, race, education, prepregnancy body mass index, current smoking, and time since delivery. Results: Of 425 women, 37 (9%) had preeclampsia and 48 (11%) had gestational hypertension during enrollment pregnancy. The postpartum visit occurred at a mean of 8.6 ± 4.4 months after delivery. Women with a history of preeclampsia had significantly higher levels of cystatin C (mean 0.86 versus 0.78 mg/L; p = 0.03) compared with normotensive women, but nonsignificant elevation in hsCRP (mean 8.39 versus 6.04 mg/L; p = 0.08). Women with gestational hypertension had no differences in mean hsCRP or cystatin C compared with normotensive women. Among the 237 women with any lactation, 78 (18%) lactated for at least 6 months. Lactation duration both in the overall sample and among women with gestational hypertension or preeclampsia was not associated with levels of hsCRP or cystatin C. Conclusions: Preeclampsia history was associated with elevated postpartum levels of cystatin C; however, duration of lactation was not associated with postpartum hsCRP or cystatin C, regardless of history of gestational hypertension or preeclampsia. Further research is needed on mechanisms through which lactation may affect maternal risk of cardiovascular disease.

Cystatin C as a novel predictor of preterm labor in severe preeclampsia

Background

The most common cause of acute kidney injury (AKI) in pregnancy is preeclampsia. Serum cystatin C (CysC) is a potential biomarker of early kidney damage as its levels are not disturbed by volume status changes in pregnancy, and serum CysC levels could serve as a replacement for conventionally used creatinine. In this study, we investigated the serum levels of CysC in severe preeclampsia cases and the associations between CysC levels and poor obstetric outcomes.

Methods

Our cohort included severe preeclampsia patients with a normal serum creatinine level. Creatinine was measured to calculate estimated glomerular filtration rate (eGFR) based on the Cockcroft and Gault, Modification of Diet in Renal Disease Study (MDRD), and Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equations, while CysC was measured to calculated eGFR based on a CysC-based equation. We then evaluated the correlations between serum CysC level, eGFR, and obstetric outcomes.

Results

Twenty-six patients were evaluated of which 38.5% delivered preterm and 30.8% had low-birth weight babies. Unlike creatinine-based eGFR and CysC-based eGFR, serum CysC demonstrate significant negative correlation with gestational age. Receiver operating characteristic curve analysis indicated that serum CysC is a potential biomarker of preterm delivery with a cut-off serum level of 1.48 mg/L with 80% sensitivity and 75% specificity.

Conclusion

GFR estimation using CysC is likely to be inaccurate in pregnancy. However, we found a significant correlation between preterm delivery and serum CysC level. Our results suggest that serum CysC level has the potential to predict preterm delivery in severe preeclampsia patients.