Soluble urokinase plasminogen activator receptor (suPAR) levels in healthy pregnancy and preeclampsia

Soluble urokinase plasminogen activator receptor in vaginally collected amniotic fluid predicting fetal inflammatory response syndrome: a prospective cohort study

BACKGROUND

Improving noninvasive antenatal diagnosis of fetal inflammatory response syndrome (FIRS) can assist in the evaluation of prenatal risk and reduce perinatal outcomes. This study aimed to determine whether soluble urokinase-type plasminogen activator receptor (suPAR) in vaginally collected amniotic fluid is significant in identifying FIRS after preterm premature rupture of membranes before 34 weeks of gestation.

METHODS

This was a prospective cohort study of 114 pregnant women and their newborns after preterm premature rupture of membranes at 22-34+6 weeks of gestation. SuPAR was evaluated using an enzyme-linked immunosorbent assay in vaginally collected amniotic fluid. Patients were classified according to the presence or absence of FIRS. FIRS was defined by umbilical cord blood interleukin-6 level > 11 pg/mL or histological funisitis. The data were analyzed using the R package (R-4.0.5).

RESULTS

SuPAR was detected in all amniotic fluid samples with a median of 26.23 ng/mL (interquartile range (IQR), 15.19-51.14). The median level of suPAR was higher in the FIRS group than in the non-FIRS group, 32.36 ng/mL (IQR, 17.27-84.16) vs. 20.46 ng/mL (IQR, 11.49-36.63) (P = 0.01), respectively. The presence of histological chorioamnionitis significantly increased the suPAR concentration in the FIRS group (P < 0.001). The areas under the curve for FIRS and FIRS with histological chorioamnionitis were 0.65 and 0.74, respectively, with an optimum cutoff value of 27.60 ng/mL. Controlling for gestational age, the cutoff of suPAR more than 27.60 ng/mL predicted threefold higher odds for FIRS and sixfold higher odds for FIRS with histologic chorioamnionitis.

CONCLUSION

Soluble urokinase-type plasminogen activator receptor in vaginally obtained amniotic fluid may assist in evaluating prenatal risk of FIRS in patients after preterm premature rupture of membranes before 34 weeks of gestation.

The role of inflammatory biomarkers in the development and progression of pre-eclampsia: a systematic review and meta-analysis

Background

Pre-eclampsia (PE) is a pregnancy complication associated with maternal and fetal morbidity and mortality. Among the potential pathogenesis discussed, inflammation is considered an essential initiator of PE. Previous studies have compared the levels of various inflammatory biomarkers that indicate the existence of PE; however, the relative levels of pro-inflammatory and anti-inflammatory biomarkers and their dynamic changes during PE progression remain unclear. This knowledge is essential to explain the occurrence and progression of the disease.

Objective

We aimed to identify the relationship between inflammatory status and PE using inflammatory biomarkers as indicators. We also discussed the underlying mechanism by which inflammatory imbalance contributes to PE by comparing the relative levels of pro-inflammatory and anti-inflammatory biomarkers. Furthermore, we identified additional risk factors for PE.

Methods

We reviewed PubMed, Embase, and the Cochrane Library for articles published until 15th September 2022. Original articles that investigated inflammatory biomarkers in PE and normal pregnancy were included. We selected healthy pregnant women as controls. The inflammatory biomarkers in the case and control groups were expressed as standardized mean differences and 95% confidence intervals using a random-effects model. Study quality was assessed using the Newcastle-Ottawa Scale. Publication bias was assessed using Egger's test.

Results

Thirteen articles that investigated 2,549 participants were included in this meta-analysis. Patients with PE had significantly higher levels of C-reactive protein (CRP), interleukin (IL)-4, IL-6, IL-8, IL-10, and tumor necrosis factor (TNF) than the controls. CRP and pro-inflammatory cytokine levels were higher than those of anti-inflammatory cytokines. Patients with gestational age > 34 weeks had significantly higher IL-6 and TNF levels. Patients with higher systolic blood pressure had significantly higher IL-8, IL-10, and CRP levels.

Conclusion

Inflammatory imbalance is an independent risk factor for PE development. Impairment of the anti-inflammatory system is a crucial initiating factor for PE development. Failed autoregulation, manifested as prolonged exposure to pro-inflammatory cytokines, leads to PE progression. Higher levels of inflammatory biomarkers suggest more severe symptoms, and pregnant women after 34 weeks of gestation are more susceptible to PE.

Soluble urokinase plasminogen activator receptor (suPAR) as a biomarker of early pregnancy location and viability compared with hCG, progesterone and estradiol

A circulating biomarker of early pregnancy outcome independent of ultrasonography and gestational age is a coveted goal. This study evaluated soluble urokinase plasminogen activator receptor (suPAR), a well-described marker of inflammation and immunological activation, for this purpose, and compared it with established early pregnancy biomarkers of the luteoplacental phase: progesterone, estradiol and hCG. We merged data from two prospective first trimester cohorts to conduct a case-control study comparing these analytes in women who had either a live birth, a miscarriage or an ectopic pregnancy. The ability to predict pregnancy location and viability was assessed by areas under the receiver operating characteristic curves (AUC). Comparing women irrespective of gestational age with a live birth, miscarriage or ectopic pregnancy showed significantly lower suPAR values in the latter group (2.4 vs. 2.4 vs. 2.0 μg/L, p = 0.032, respectively), as were all other analytes. Before 6 weeks' gestation, suPAR was significantly inferior to progesterone, estradiol and hCG in pregnancy location and viability prediction (in 124 pregnancies, suPAR AUC_location = 0.69 [CI: 0.54-0.83] and AUC_viability = 0.58 [CI: 0.48-0.69], while progesterone AUC_location = 0.95 [CI: 0.87-1.00] and AUC_viability = 0.84 [CI: 0.75-0.92]). After 6 weeks' gestation, suPAR prediction improved but was inferior to hCG, progesterone and estradiol (in 188 pregnanices, suPAR AUC_location = 0.71 [CI: 0.63-0.78] and AUC_viability = 0.70 [CI: 0.63-0.78] compared with hCG AUC_location = 0.96 [CI: 0.93-0.99] and AUC_viability = 0.96 [CI: 0.93-0.98]). Collectively, suPAR is less useful as a predictor of early pregnancy outcome than hCG, progesterone and estradol.

Inflammatory Markers and Preeclampsia: A Systematic Review

BACKGROUND

Preeclampsia (PE), a serious and variable pregnancy complication affecting 5%-10% of the obstetric population, has an undetermined etiology, yet inflammation is concomitant with its development, particularly in relation to endothelial dysfunction.

OBJECTIVE

The purpose of this systematic review was to examine the published evidence concerning an association between PE and inflammatory markers for their usefulness in the prediction or early identification of women with PE in antepartum clinical settings.

METHODS

In this systematic review, we used the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The Cumulative Index for Nursing and Allied Health and MEDLINE/OVID were the electronic databases used for identifying published articles. We placed no time limit on the publication year.

RESULTS

The search generated 798 articles. After removing duplicates, screening abstracts, and conducting full-text reviews, we retained 73 articles and examined 57 unique markers. This review shows that C-reactive protein and the cytokines, specifically the proinflammatory markers IL-6, IL-8, and tumor necrosis factor alpha, garner the most support as potential inflammatory markers for clinical surveillance of PE, particularly during the second and third trimesters.

DISCUSSION

Based on this review, we cannot recommend any single inflammatory marker for routine clinical use to predict/identify PE onset or progression. Research is recommended to examine a combination panel of these four inflammatory markers both with and without clinical risk factors toward the goal of translation to practice.

Soluble urokinase-type plasminogen activator receptor and urokinase-type plasminogen activator receptor contribute to chemoresistance in leukemia

The soluble urokinase-type plasminogen activator receptor (suPAR) and the urokinase-type plasminogen activator receptor (uPAR) have been proposed as useful biomarkers of tumor progression. Recently, suPAR was associated with chemoresistance in lung cancer. However, its clinical significance in leukemia has not previously been investigated. The present study examined the plasma levels of suPAR and the expression of the uPAR on bone marrow (BM) cells in 86 patients with leukemia at diagnosis prior to chemotherapy and 26 normal subjects (control group). The plasma suPAR levels were measured using ELISA, whilst uPAR expression was assayed by flow cytometry analysis. In addition, cell surface uPAR expression on K562 and multidrug-resistant K562/ADM cell lines was studied by western blotting. On admission and follow-up, the levels of suPAR in patients with leukemia were significantly increased compared with controls. Systemic levels of suPAR were strongly associated with the numbers of white blood cells. A case was defined as uPAR-positive (uPAR+) if >20% of the gated cells expressed uPAR. In comparison with 26 healthy BM samples that were negative for uPAR expression, 48 (55.8%) of the 86 leukemia patients were uPAR+. uPAR expression on the cell surface of multidrug-resistant K562/ADM cells was increased compared with that on K562 cells. In conclusion, plasma suPAR expression may be a useful marker for subtype classification of patients with leukemia and cell surface uPAR may be associated with resistance to chemotherapy or disease progression.

Impact of lifestyle intervention for obese women during pregnancy on maternal metabolic and inflammatory markers

BACKGROUND

Offspring of obese mothers have increased risk of developing obesity and related short- and long-term disease. The cause is multifactorial and may partly be explained by the unfavorable intrauterine environment. Intervention during pregnancy leading to a healthier lifestyle among obese may alter this.

OBJECTIVE

To assess the effect of lifestyle intervention on markers of maternal metabolism and inflammation in 'the TOP (Treatment of Obese Pregnant Women) study', a randomized controlled trial.

METHODS

In the TOP-study 425 participants with body mass index ⩾30 kg/m² were randomized to intervention with dietary advices and physical activity assessed by pedometer (PA+D), physical activity assessed by pedometer (PA) or control (C). Of 389 participants completing the study 376 had available blood samples. Serum was analyzed for insulin, c-peptide, lipid profile, leptin, high-sensitivity CRP (hsCRP) and Soluble urokinase Plasminogen Activator Receptor (suPAR), in week 18-20 and 28-30, and simultaneously a 2-h oral glucose-tolerance-test was performed. Diet was assessed in gestational week 11-14 and 36-37 using a validated 360-item Food Frequency Questionnaire.

RESULTS

Median levels of hsCRP in gestational week 28-30 were lower in each of the intervention groups (8.3 mg/l in PA+D group, P=0.03; and 8.8 mg/l in PA group, P=0.02) versus the control group (11.5 mg/l). Obtaining 11 000 steps per day as aimed for resulted in a 21% lower hsCRP compared to non-compliant women. Women reporting high carbohydrate intake had around 30% higher hsCRP concentrations in late gestation than women reporting the lowest intake. There were no differences in lipid profile or any of the metabolic markers in gestational week 28-30 when comparing the intervention and control groups.

CONCLUSIONS

Lifestyle intervention in obese women can reduce hsCRP representing a marker of inflammation during pregnancy. The effect may partly be mediated by more physical activity and partly by changes in intake of carbohydrates and the glycaemic load.

Peripheral and placental biomarkers in women with placental malaria: a systematic review

Placental malaria (PM) causes significant morbidity in mothers and infants. Diagnosis of PM during pregnancy is however problematic due to placental sequestration of parasites. Host biomarkers may therefore be used as a diagnostic method. In this systematic review most studies focused on inflammatory markers. A trend was observed for increased IL-10 and TNF-α in PM positives. These markers are however unspecific, thus a combination of multiple biomarkers involved in different pathophysiological pathways of PM is indicated. Of interest are inflammatory markers (TNF-R2, CXCL-13), markers of lipid metabolism (APO-B), angiogenesis (sFlt-1) and hormones (estradiol). As the majority of published studies tested biomarker levels only at delivery, more longitudinal cohort studies will be necessary to detect biomarkers during pregnancy that can predict PM.

Inflammatory markers in the second trimester prior to clinical onset of preeclampsia, intrauterine growth restriction, and spontaneous preterm birth

Low-grade inflammation has been associated with pregnancy complications including preeclampsia (PE), intrauterine growth restriction (IUGR), and spontaneous preterm birth (SPB). In an unmatched, nested case-control study, we assessed the possible predictive association of maternal C-reactive protein (CRP), interferon-γ-inducible protein 10 (IP-10), and soluble urokinase plasminogen activator receptor (suPAR) in second trimester plasma samples in relation to later development of PE (n = 29), IUGR (n = 53), and SPB (n = 9). Inflammatory marker levels in these groups were compared to normotensive healthy pregnant controls (n = 127). We found no statistically significant difference in CRP, IP-10, or suPAR in second trimester plasma samples from pregnant women with later PE, IUGR, and SPB when compared to normotensive healthy controls. Second trimester plasma samples of CRP, IP-10, and suPAR cannot be used as a prognostic marker for PE, IUGR, and SPB.

Relationship of circulating soluble urokinase plasminogen activator receptor (suPAR) levels to disease control in asthma and asthmatic pregnancy

Asthma has a high burden of morbidity if not controlled and may frequently complicate pregnancy, posing a risk for pregnancy outcomes. Elevated plasma level of the inflammatory biomarker soluble urokinase plasminogen activator receptor (suPAR) is related to a worse prognosis in many conditions such as infectious, autoimmune, or pregnancy-related diseases; however the value of suPAR in asthma and asthmatic pregnancy is unknown. The present study aimed to investigate the suPAR, CRP and IL-6 levels in asthma (asthmatic non-pregnant, ANP; N = 38; female N = 27) and asthmatic pregnancy (AP; N = 15), compared to healthy non-pregnant controls (HNP; N = 29; female N = 19) and to healthy pregnant women (HP; N = 58). The relationship between suPAR levels and asthma control was also evaluated. The diagnostic efficacy of suPAR in asthma control was analyzed using ROC analysis. IL-6 and CRP levels were comparable in all study groups. Circulating suPAR levels were lower in HP and AP than in HNP and ANP subjects, respectively (2.01 [1.81–2.38] and 2.39 [2.07–2.69] vs. 2.60 [1.82–3.49] and 2.84 [2.33–3.72] ng/mL, respectively, p = 0.0001). suPAR and airway resistance correlated in ANP (r = 0.47, p = 0.004). ROC analysis of suPAR values in ANP patients with PEF above and below 80% yielded an AUC of 0.75 (95% CI: 0.57–0.92, p = 0.023) and with ACT total score above and below 20 an AUC of 0.80 (95% CI: 0.64–0.95, p = 0.006). The cut-off value of suPAR to discriminate between controlled and not controlled AP and ANP was 4.04 ng/mL. In conclusion, suPAR may help the objective assessment of asthma control, since it correlates with airway resistance and has good sensitivity in the detection of impaired asthma control. Decrease in circulating suPAR levels detected both in healthy and asthmatic pregnant women presumably represents pregnancy induced immune tolerance.

Plasma soluble urokinase plasminogen activator receptor (suPAR) levels in systemic lupus erythematosus

OBJECTIVE

Soluble urokinase plasminogen activator receptor (suPAR) is a biomarker of systemic inflammation. We aimed to characterize plasma suPAR levels in SLE patients.

METHODS

We measured plasma suPAR, C reactive protein (CRP) and erythrocyte sedimentation rate (ESR) in 89 SLE patients and 29 healthy controls.

RESULTS

suPAR and ESR values were higher in SLE than in controls, while CRP levels were comparable. ROC analysis of suPAR levels indicated a cut-off value of 5.70 ng/mL to distinguish patients with high disease activity (SLEDAI >8).

CONCLUSION

suPAR might be an objective marker for identifying SLE patients with active disease.

Serum soluble urokinase plasminogen activator receptor (suPAR) in early pregnancy prior to clinical onset of preeclampsia

OBJECTIVE

To examine whether soluble urokinase plasminogen activator receptor (suPAR) in early pregnancy could be a risk marker for later development of preeclampsia.

DESIGN

Case-control study.

SETTING

Hospital-based.

POPULATION

The study comprised 43 pregnant women developing preeclampsia (cases) and 86 pregnant women not developing the disorder (controls). Each case was matched with two controls with respect to pre-pregnancy body mass index, gestational age at time of blood collection, storage time of blood samples and maternal age.

METHODS

The samples had been taken predominantly in the first trimester as part of a routine serological screening for rubella, HIV and toxoplasmosis of Norwegian pregnant women, and were analyzed by a commercially available enzyme-linked immunosorbent suPARnostic® assay kit (ELISA, Virogates, Copenhagen, Denmark).

RESULTS

There was no significant difference between median suPAR levels in women who subsequently developed preeclampsia and those who did not (4.5 in the case group vs. 4.3 ng/mL in the control group, p= 0.49). The suPAR levels were relatively high compared with levels in non-pregnant women, reflecting some general physiological responsiveness associated with pregnancy irrespective of preeclampsia. The suPAR level was not related to maternal body mass index, maternal age or sample storage time, nor did it show any association with the following fetal characteristics: body weight, body length, placental weight, delivery method or gender.

CONCLUSION

suPAR did not appear to be a useful early pre-clinical marker of preeclampsia.