Predictive markers of pre-eclampsia in hypertensive disorders of pregnancy

Plasma osteopontin concentrations in preeclampsia - is there an association with endothelial injury?

Abstract Background: It has been previously reported that plasma osteopontin (OPN) concentrations are increased in cardiovascular disorders. The goal of the present study was to determine plasma OPN concentrations in healthy pregnant women and preeclamptic patients, and to investigate their relationship to the clinical characteristics of the study subjects and to markers of inflammation [C-reactive protein (CRP)], endothelial activation [von Willebrand factor antigen (VWF:Ag)] or endothelial injury (fibronectin), oxidative stress [malondialdehyde (MDA)] and trophoblast debris (cell-free fetal DNA).

METHODS

Forty-four patients with preeclampsia and 44 healthy pregnant women matched for age and gestational age were involved in this case-control study. Plasma OPN concentrations were measured with ELISA. Serum CRP concentrations were determined with an autoanalyzer using the manufacturer's reagents. Plasma VWF:Ag was quantified by ELISA, while plasma fibronectin concentrations were measured by nephelometry. Plasma MDA concentrations were estimated by the thiobarbituric acid-based colorimetric assay. The amount of cell-free fetal DNA in maternal plasma was determined by quantitative real-time PCR analysis of the sex-determining region Y (SRY) gene. For statistical analyses, non-parametric methods were applied.

RESULTS

Serum levels of CRP, as well as plasma concentrations of VWF:Ag, fibronectin, MDA and cell-free fetal DNA were significantly higher in preeclamptic patients than in healthy pregnant women. There was no significant difference in plasma OPN concentrations between controls and the preeclamptic group. However, preeclamptic patients with plasma fibronectin concentrations in the upper quartile had significantly higher plasma OPN concentrations than those below the 75th percentile, as well as healthy pregnant women [median (interquartile range): 9.38 (8.10-11.99) vs. 7.54 (6.31-9.40) and 7.40 (6.51-8.80) ng/mL, respectively, p<0.05 for both]. Furthermore, in preeclamptic patients, plasma OPN concentrations showed a significant positive linear association with plasma fibronectin (Spearman R=0.38, standardized regression coefficient (beta)=0.41, p<0.05 for both).

CONCLUSIONS

Plasma OPN concentrations are increased in preeclamptic patients with extensive endothelial injury. However, further studies are warranted to explore the relationship between OPN and endothelial damage. Clin Chem Lab Med 2010;48:181-7.

Relationship between urinary albumin and serum soluble fms-like tyrosine kinase 1 (sFlt-1) in normal pregnancy

OBJECTIVE

To investigate if the circulating level of soluble fms-like tyrosine kinase 1 (sFlt-1) and vascular endothelial growth factor (VEGF) correlates with urinary albumin excretion in normal pregnancy.

STUDY DESIGN

Serum specimens and 24h urine collections were requested from normal pregnant women at 28-30 weeks of gestation and the following laboratory tests were performed: serum creatinine, urinary protein, urinary albumin and creatinine clearance. For the present study, 117 normal pregnant women were selected as subjects. Subjects' serum was tested to determine sFlt-1 and VEGF concentrations by ELISA. The correlation between sFlt-1 or VEGF concentrations in the serum and renal laboratory variables were analyzed. Simple regression was used to evaluate the correlations.

RESULTS

A significant association was noted between serum sFlt-1 concentration and urinary albumin excretion (r=0.68; P<.0001). Similarly, a significant association was noted between serum VEGF concentration and urinary albumin excretion (r=-0.39; P<.0001). Other urinary variables showed no correlations with either sFlt-1 or VEGF.

CONCLUSION

Even in normal pregnancy, albumin excretion is affected by an increase in placentally derived sFlt-1. If the sFlt-1 level is kept within normal range, only glomerular endothelial cells are affected and this phenomenon does not spread to the endothelial cells of a whole body.

Evaluation of natural coagulation inhibitor levels in various hypertensive states of pregnancy

OBJECTIVE

To evaluate the role of natural coagulation inhibitors in various classifications of pregnancy associated hypertension in Turkish population living in Trakya region of Turkey.

STUDY DESIGN

Serum uric acid levels, plasma protein C (PC), protein S (PS), antithrombin III (AT III) activities and activated protein C resistance (APCR) were measured in 80 pregnant women with hypertension (preeclampsia, n = 32; severe preeclampsia, n = 25; eclampsia, n = 14; chronic hypertension, n = 9) and 58 healthy pregnant women. Tukey and Tamhane multiple comparison tests, Kruskal-Wallis, chi2 and Fisher's exact tests were performed for comparison of means and/or medians.

RESULTS

Serum uric acid levels were significantly elevated in women with preeclampsia and severe preeclampsia, but PS activity decreased in women with severe preeclampsia (33.2 +/- 18.9% versus 50.4 +/- 22.7%, p = 0.015) and chronic hypertension (29.5 +/- 14.5% versus 50.4+ /- 22.7%, p = 0.045) compared to healthy controls. There was no significant difference in APCR, and PC or AT III activity between the groups. Platelet counts were significantly lower in women with severe preeclampsia, compared to controls and women with chronic hypertension.

CONCLUSION(S)

Serum uric acid levels and plasma protein S activity may be useful as indices of severity of pathology in pregnancy associated hypertension.

Maternal plasma cellular fibronectin concentrations in normal and preeclamptic pregnancies: a longitudinal study for early prediction of preeclampsia

OBJECTIVE

The purpose of this study was to examine cellular fibronectin levels throughout normotensive and preeclamptic pregnancies and to analyze its predictive value for the detection of preeclampsia within the second trimester of pregnancy.

STUDY DESIGN

Blood samples were collected at 4-week intervals from 378 healthy, nulliparous women who were recruited before 16 weeks of gestation. Preeclampsia developed in 26 patients; 52 normotensive control subjects were matched from the same cohort. Plasma samples were assayed for ED-B fibronectin by enzyme-linked immunosorbent assay. Trends were compared between groups. Predictive values were determined with the use of second trimester assessments.

RESULTS

In both groups, fibronectin levels rose as pregnancy advanced, but in women with preeclampsia, this increase was significantly higher (94.5% vs 31.8%; P =.006). Throughout pregnancy, patients with preeclampsia exhibited significantly higher fibronectin levels than did control subjects. As early as 9 to 12 weeks of gestation, a difference was established (preeclampsia, 3.72 +/- 0.21; control, 2.94 +/- 0.22 microg/mL [mean +/- SEM]; P =.008). The best cutoff point and time interval to calculate predictive values were 3.8 microg/mL and 22 to 26 weeks of gestation, respectively. Sensitivity, specificity, and positive and negative predictive values were 73%, 87%, 29%, and 98%, respectively; the odds ratio was 16.1 (95% CI, 8.6-30.2).

CONCLUSION

In women in whom clinical preeclampsia developed, endothelial damage seemed to be present since early gestation. Cellular fibronectin levels of >or=3.8 microg/mL within 22 to 26 weeks of gestation may help in the early detection of preeclampsia in healthy nulliparous women.

The role of serum uric acid as a prognostic indicator of the severity of maternal and fetal complications in hypertensive pregnancies

OBJECTIVE

To examine whether an elevated serum uric acid level in hypertensive pregnant women is a useful prognostic indicator of severe hypertension; hemolysis, elevated liver enzymes, low platelets (HELLP) syndrome; and small for gestational age (SGA) infants.

METHODS

A total of 459 women newly diagnosed with hypertension in pregnancy were categorized into "gestational hypertension" and "hypertension with proteinuria (preeclampsia)" groups. Their serum uric acid levels were correlated with the development of HELLP syndrome, severity of hypertension, and incidence of SGA newborns (< 10th percentile birth weight). HELLP syndrome was divided into 3 classes depending on the severity of the thrombocytopenia. Prior to this study, serum uric acid levels had been measured in a group of normotensive women. Mean and standard deviation of serum uric acid levels for each group were compared using analysis of variance and student t-tests, where necessary.

RESULTS

Significant elevation in serum uric acid levels over normotensive pregnant women (285 +/- 72 micromol/L) was observed in both the gestational hypertensive group (341 +/- 83 micromol/L) and the preeclamptic group (384 +/- 93 micromol/L) of women (p < 0.001 and p < 0.05 respectively). Serum uric acid levels were also significantly elevated (p < 0.001) in women with gestational hypertension with HELLP syndrome (382 +/- 78 micromol/L) compared to those without HELLP syndrome (330 +/- 80 micromol/L). Preeclamptic women with HELLP syndrome (412 +/- 99 micromol/L) also demonstrated elevated uric acid levels (p < 0.05) over those without HELLP syndrome (374 +/- 87 micromol/L). However, the level of uric acid did not predict the severity of HELLP syndrome. The presence of SGA infants in the gestational hypertensive group was not associated with increased uric acid levels.

CONCLUSION

Uric acid levels, although significantly elevated in women with gestational hypertension and preeclampsia as compared to normotensive pregnant women, are not good prognostic indicators of the severity of the maternal or fetal complications.