[Predictive value of the sFlt1/PlGF ratio for the diagnosis of preeclampsia in high-risk patients]

Early gestational profiling of oxidative stress and angiogenic growth mediators as predictive, preventive and personalised (3P) medical approach to identify suboptimal health pregnant mothers likely to develop preeclampsia

BACKGROUND

Pregnant women, particularly in developing countries are facing a huge burden of preeclampsia (PE) leading to high morbidity and mortality rates. This is due to delayed diagnosis and unrecognised early targeted preventive measures. Adapting innovative solutions via shifting from delayed to early diagnosis of PE in the context of predictive diagnosis, targeted prevention and personalisation of medical care (PPPM/3 PM) is essential. The subjective assessment of suboptimal health status (SHS) and objective biomarkers of oxidative stress (OS) and angiogenic growth mediators (AGMs) could be used as new PPPM approach for PE; however, these factors have only been studied in isolation with no data on their combine assessment. This study profiled early gestational biomarkers of OS and AGMs as 3 PM approach to identify SHS pregnant mothers likely to develop PE specifically, early-onset PE (EO-PE) and late-onset PE (LO-PE).

METHODS

A prospective cohort of 593 singleton normotensive pregnant (NTN-P) women were recruited at 10-20th (visit 1) and followed from 21 weeks gestation until the time of PE diagnosis and delivery. At visit 1, SHS was assessed using SHS questionnaire-25 (SHSQ-25) and women were classified as SHS and optimal health status (OHS). Biomarkers of OS (8-hydroxy-2-deoxyguanosine [8-OHdG], 8-epi-prostaglansinF2alpha [8-epi-PGF2α] and total antioxidant capacity [TAC]) and AGMs (vascular endothelial growth factor [VEGF-A], soluble Fms-like tyrosine kinase-1 [sFlt-1], placental growth factor [PlGF] and soluble endoglin [sEng]) were measured at visit 1 and time of PE diagnosis.

RESULTS

Of the 593 mothers, 498 (248 SHS and 250 OHS) returned for delivery and were included in the final analysis. Fifty-six, 97 and 95 of the 248 SHS mothers developed EO-PE, LO-PE and NTN-P respectively, versus 14 EO-PE, 30 LO-PE and 206 NTN-P among the 250 OHS mothers. At the 10-20th week gestation, unbalanced levels of OS and AGMs were observed among SHS women who developed EO-PE than LO-PE compared to NTN-P women (p < 0.0001). The combined ratios of OS and AGMs, mainly the levels of 8-OHdG/PIGF ratio at 10-20th week gestation yielded the best area under the curve (AUC) and highest relative risk (RR) for predicting SHS-pregnant women who developed EO-PE (AUC = 0.93; RR = 6.5; p < 0.0001) and LO-PE (AUC = 0.88, RR = 4.4; p < 0.0001), as well as for OHS-pregnant women who developed EO-PE (AUC = 0.89, RR = 5.6; p < 0.0001) and LO-PE (AUC = 0.85; RR = 5.1; p < 0.0001).

CONCLUSION

Unlike OHS pregnant women, SHS pregnant women have high incidence of PE coupled with unbalanced levels of OS and AGMs at 10-20 weeks gestation. Combining early gestational profiling of OS and AGMs created an avenue for early differentiation of PE subtypes in the context of 3 PM care for mothers at high risk of PE.

Biochemical tests of placental function versus ultrasound assessment of fetal size for stillbirth and small-for-gestational-age infants

BACKGROUND

Stillbirth affects 2.6 million pregnancies worldwide each year. Whilst the majority of cases occur in low- and middle-income countries, stillbirth remains an important clinical issue for high-income countries (HICs) - with both the UK and the USA reporting rates above the mean for HICs. In HICs, the most frequently reported association with stillbirth is placental dysfunction. Placental dysfunction may be evident clinically as fetal growth restriction (FGR) and small-for-dates infants. It can be caused by placental abruption or hypertensive disorders of pregnancy and many other disorders and factorsPlacental abnormalities are noted in 11% to 65% of stillbirths. Identification of FGA is difficult in utero. Small-for-gestational age (SGA), as assessed after birth, is the most commonly used surrogate measure for this outcome. The degree of SGA is associated with the likelihood of FGR; 30% of infants with a birthweight < 10th centile are thought to be FGR, while 70% of infants with a birthweight < 3rd centile are thought to be FGR. Critically, SGA is the most significant antenatal risk factor for a stillborn infant. Correct identification of SGA infants is associated with a reduction in the perinatal mortality rate. However, currently used tests, such as measurement of symphysis-fundal height, have a low reported sensitivity and specificity for the identification of SGA infants.

OBJECTIVES

The primary objective was to assess and compare the diagnostic accuracy of ultrasound assessment of fetal growth by estimated fetal weight (EFW) and placental biomarkers alone and in any combination used after 24 weeks of pregnancy in the identification of placental dysfunction as evidenced by either stillbirth, or birth of a SGA infant. Secondary objectives were to investigate the effect of clinical and methodological factors on test performance.

SEARCH METHODS

We developed full search strategies with no language or date restrictions. The following sources were searched: MEDLINE, MEDLINE In Process and Embase via Ovid, Cochrane (Wiley) CENTRAL, Science Citation Index (Web of Science), CINAHL (EBSCO) with search strategies adapted for each database as required; ISRCTN Registry, UK Clinical Trials Gateway, WHO International Clinical Trials Portal and ClinicalTrials.gov for ongoing studies; specialist abstract and conference proceeding resources (British Library's ZETOC and Web of Science Conference Proceedings Citation Index). Search last conducted in Ocober 2016.

SELECTION CRITERIA

We included studies of pregnant women of any age with a gestation of at least 24 weeks if relevant outcomes of pregnancy (live birth/stillbirth; SGA infant) were assessed. Studies were included irrespective of whether pregnant women were deemed to be low or high risk for complications or were of mixed populations (low and high risk). Pregnancies complicated by fetal abnormalities and multi-fetal pregnancies were excluded as they have a higher risk of stillbirth from non-placental causes. With regard to biochemical tests, we included assays performed using any technique and at any threshold used to determine test positivity.

DATA COLLECTION AND ANALYSIS

We extracted the numbers of true positive, false positive, false negative, and true negative test results from each study. We assessed risk of bias and applicability using the QUADAS-2 tool. Meta-analyses were performed using the hierarchical summary ROC model to estimate and compare test accuracy.

MAIN RESULTS

We included 91 studies that evaluated seven tests - blood tests for human placental lactogen (hPL), oestriol, placental growth factor (PlGF) and uric acid, ultrasound EFW and placental grading and urinary oestriol - in a total of 175,426 pregnant women, in which 15,471 pregnancies ended in the birth of a small baby and 740 pregnancies which ended in stillbirth. The quality of included studies was variable with most domains at low risk of bias although 59% of studies were deemed to be of unclear risk of bias for the reference standard domain. Fifty-three per cent of studies were of high concern for applicability due to inclusion of only high- or low-risk women.Using all available data for SGA (86 studies; 159,490 pregnancies involving 15,471 SGA infants), there was evidence of a difference in accuracy (P < 0.0001) between the seven tests for detecting pregnancies that are SGA at birth. Ultrasound EFW was the most accurate test for detecting SGA at birth with a diagnostic odds ratio (DOR) of 21.3 (95% CI 13.1 to 34.6); hPL was the most accurate biochemical test with a DOR of 4.78 (95% CI 3.21 to 7.13). In a hypothetical cohort of 1000 pregnant women, at the median specificity of 0.88 and median prevalence of 19%, EFW, hPL, oestriol, urinary oestriol, uric acid, PlGF and placental grading will miss 50 (95% CI 32 to 68), 116 (97 to 133), 124 (108 to 137), 127 (95 to 152), 139 (118 to 154), 144 (118 to 161), and 144 (122 to 161) SGA infants, respectively. For the detection of pregnancies ending in stillbirth (21 studies; 100,687 pregnancies involving 740 stillbirths), in an indirect comparison of the four biochemical tests, PlGF was the most accurate test with a DOR of 49.2 (95% CI 12.7 to 191). In a hypothetical cohort of 1000 pregnant women, at the median specificity of 0.78 and median prevalence of 1.7%, PlGF, hPL, urinary oestriol and uric acid will miss 2 (95% CI 0 to 4), 4 (2 to 8), 6 (6 to 7) and 8 (3 to 13) stillbirths, respectively. No studies assessed the accuracy of ultrasound EFW for detection of pregnancy ending in stillbirth.

AUTHORS' CONCLUSIONS

Biochemical markers of placental dysfunction used alone have insufficient accuracy to identify pregnancies ending in SGA or stillbirth. Studies combining U and placental biomarkers are needed to determine whether this approach improves diagnostic accuracy over the use of ultrasound estimation of fetal size or biochemical markers of placental dysfunction used alone. Many of the studies included in this review were carried out between 1974 and 2016. Studies of placental substances were mostly carried out before 1991 and after 2013; earlier studies may not reflect developments in test technology.

Polymorphism-801G/A in the 3'-untranslated region of CXCL12 is not associated with preeclampsia in Chinese Han population

OBJECTIVE

We investigated whether the CXCL12-801G/A polymorphism was associated with preeclampsia (PE) susceptibility in a Chinese Han population.

METHODS

We examined 912 PE women and 1025 controls for the CXCL12-801G/A polymorphism by polymerase chain reaction (PCR) and correlations with clinical characteristics were examined.

RESULTS

No significant differences in genotypic and allelic frequencies of CXCL12-G801A were found between cases and controls (genotype: χ² = 2.095, p = 0.351; allele: χ² = 1.713, p = 0.191). There were also no significant differences between early/late-onset or mild/severe PE and control groups.

CONCLUSION

The results indicate that 801G/A in CXCL12 may not play a major role in pathogenesis of PE in a Chinese Han population.

A Common Profile of Disordered Angiogenic Factor Production and the Exacerbation of Inflammation in Early Preeclampsia, Late Preeclampsia, and Intrauterine Growth Restriction

Preeclampsia and intrauterine growth restriction are two separate disease entities that, according to numerous reports, share the same pathogenesis. In both, angiogenesis disorders and generalized inflammation are the dominant symptoms. In this study, we hypothesized that both diseases demonstrate the same profile in early preeclampsia, late preeclampsia, and intrauterine growth restriction patients, with the only difference being the degree of exacerbation of lesions. One hundred sixty-seven patients were enrolled in the study and divided into four groups: early preeclampsia, late preeclampsia, and intrauterine growth restriction groups, and one control group. Concentrations of the angiogenesis and inflammatory markers soluble fms-like tyrosine kinase receptor 1, placental growth factor, high-sensitivity C-reactive protein, and interleukin-6 were determined, and the behavior of these markers and correlations among them were studied. Higher concentrations of soluble fms-like tyrosine kinase receptor 1, high-sensitivity C-reactive protein, and interleukin-6 and a lower concentration of placental growth factor were observed in the study groups compared with the control group. No differences in concentrations of the studied markers were found among the study groups but significant correlations were observed. The higher values for the angiogenesis and inflammatory markers both in preeclampsia patients and patients with intrauterine growth restriction of placental origin compared with the control group suggest the existence of the same underlying disorders in the development of these pathologies. The observed mutual correlations for disordered angiogenesis and inflammatory markers are suggestive of a mutual relationship between these processes in the development of pathologies evolving secondary to placental ischemia. The same lesion profile was observed for both preeclampsia and ‘placental’ intrauterine growth restriction patients, which could be used in developing common diagnostic criteria for pregnant patients.

Using Doppler ultrasound of the uterine and umbilical arteries and disordered angiogenesis markers (sFlt-1/PlGF) in unified monitoring of ischemic placental syndrome patients

OBJECTIVE

The shared pathogenesis of placental ischemia entitles us to create a single treatment model. We attempted to develop a unified method for monitoring ischemic placental syndrome patients using Doppler ultrasound of the uterine and umbilical arteries and disordered angiogenesis markers sFlt-1 and PlGF.

MATERIAL AND METHODS

182 pregnant women suffering from the ischemic placental syndrome were divided into four groups depending on the severity of their lesions revealed in the Doppler ultrasound examination and weeks of pregnancy. We analyzed the behavior of clinical and biochemical parameters in these groups and the correlations between the ultrasound examination and the disordered angiogenesis markers.

RESULTS

In the group of patients demonstrating more severe Doppler ultrasound lesions, the clinical and biochemical parameters were significantly more expressed, whereas unfavorable obstetric events occurred either earlier or more frequently. Lesions revealed in Doppler occur more commonly in groups before 34th week of pregnancy. Disordered angiogenesis markers are significantly correlated with ultrasound examination results.

CONCLUSIONS

A unified method for monitoring the ischemic placental syndrome based on pathogenetic, biophysical (Doppler ultrasound), and biochemical (sFlt-1/PlGF) parameters is feasible and constitutes a valuable supplement to the existing standards, while the high correlations between Doppler ultrasound examinations and both sFlt-1 and PlGF point to a shared pathogenesis of the lesions. Intensity of Doppler changes is connected with time of testing and pregnancy duration.

J. The role of angiogenic factors in preeclampsia

Preeclampsia is one of the most common and most serious complications of pregnancy and the management of this condition still challenges obstetricians. Despite intensive research the etiology of preeclampsia still remains unclear. At the beginning of the 2000s preeclampsia-related research was directed towards factors that influence angiogenesis. Most studies have been carried out on the placental growth factor and soluble fms-like tyrosine kinase-1. Most publications confirm the increased concentrations of antiangiogenic factors and decreased concentrations of proangiogenic factors in maternal blood samples in preeclampsia even before the onset of clinical symptoms. According to our current knowledge antiangiogenic proteins are responsible for the endothelial dysfunction in the symptomatic stage of the disease. Placental growth factor and soluble fms-like tyrosine kinase-1 may have important roles in the prediction and treatment of the disease. The point of care detection of placental growth factor and soluble fms-like tyrosine kinase-1 may be used to predict preeclampsia. Rapid tests are available to determine the serum levels of the two proteins. Removal of soluble fms-like tyrosine kinase-1 from maternal circulation is a potential treatment option for early onset preeclampsia. Orv. Hetil., 2014, 155(47), 1860–1866.