The value of a single combined measurement of VEGF, glycodelin, progesterone, PAPP-A, HPL and LIF for differentiating between ectopic and abnormal intrauterine pregnancy

Multiplexed serum biomarkers to discriminate nonviable and ectopic pregnancy

OBJECTIVE

To evaluate combinations of candidate biomarkers to develop a multiplexed prediction model for identifying the viability and location of an early pregnancy. In this study, we assessed 24 biomarkers with multiple machine learning-based methodologies to assess if multiplexed biomarkers may improve the diagnosis of normal and abnormal early pregnancies.

DESIGN

A nested case-control design evaluated the predictive ability and discrimination of biomarkers in patients at risk of early pregnancy failure in the first trimester to classify viability and location.

SETTING

Three university hospitals.

PATIENTS

A total of 218 individuals with pain and/or bleeding in early pregnancy: 75 had an ongoing intrauterine gestation; 68 had ectopic pregnancies (EPs); and 75 had miscarriages.

INTERVENTIONS

Serum levels of 24 biomarkers were assessed in the same patients. Multiple machine learning-based methodologies to evaluate combinations of these top candidates to develop a multiplexed prediction model for the identification of a nonviable pregnancy (ongoing intrauterine pregnancy vs. miscarriage or EP) and an EP (EP vs. ongoing intrauterine pregnancy or miscarriage).

MAIN OUTCOME MEASURES

The predicted classification using each model was compared with the actual diagnosis, and sensitivity, specificity, positive predictive value, negative predictive value, conclusive classification, and accuracy were calculated.

RESULTS

Models using classification regression tree analysis using 3 (pregnancy-specific beta-1-glycoprotein 3 [PSG3], chorionic gonadotropin-alpha subunit, and pregnancy-associated plasma protein-A) biomarkers were able to predict a maximum sensitivity of 93.3% and a maximum specificity of 98.6%. The model with the highest accuracy was 97.4% (with 70.2% receiving classification). Models using an overlapping group of 3 (soluble fms-like tyrosine kinase-1, PSG3, and tissue factor pathway inhibitor 2) biomarkers achieved a maximum sensitivity of 98.5% and a maximum specificity of 95.3%. The model with the highest accuracy was 94.4% (with 65.6% receiving classification). When the models were used simultaneously, the conclusive classification increased to 72.7% with an accuracy of 95.9%. The predictive ability of the biomarkers in the random forest produced similar test characteristics when using 11 predictive biomarkers.

CONCLUSION

We have demonstrated a pool of biomarkers from divergent biological pathways that can be used to classify individuals with potential early pregnancy loss. The biomarkers choriogonadotropin alpha, pregnancy-associated plasma protein-A, and PSG3 can be used to predict viability, and soluble fms-like tyrosine kinase-1, tissue factor pathway inhibitor 2, and PSG3 can be used to predict pregnancy location.

Evaluation of novel biomarkers for early pregnancy outcome prediction†

OBJECTIVE

To assess performance and discriminatory capacity of commercially available enzyme-linked immunosorbent assays of biomarkers for predicting first trimester pregnancy outcome in a multi-center cohort.

DESIGN

In a case-control study at three academic centers of women with pain and bleeding in early pregnancy, enzyme-linked immunosorbent assays of biomarkers were screened for assay performance. Performance was assessed via functional sensitivity, assay reportable range, recovery/linearity, and intra-assay precision (%Coefficient of Variation). Top candidates were analyzed for discriminatory capacity for viability and location among 210 women with tubal ectopic pregnancy, viable intrauterine pregnancy, or miscarriage. Assay discrimination was assessed by visual plots, area under the curve with 95% confidence intervals, and measures of central tendency with two-sample t-tests.

RESULTS

Of 25 biomarkers evaluated, 22 demonstrated good or acceptable assay performance. Transgelin-2, oviductal glycoprotein, and integrin-linked kinase were rejected due to poor performance. The best biomarkers for discrimination of pregnancy location were pregnancy-specific beta-1-glycoprotein 9, pregnancy-specific beta-1-glycoprotein 1, insulin-like growth factor binding protein 1, kisspeptin (KISS1), pregnancy-specific beta-1-glycoprotein 3, and beta parvin (PARVB). The best biomarkers for discrimination of pregnancy viability were pregnancy-specific beta-1-glycoprotein 9, pregnancy-specific beta-1-glycoprotein 3, EH domain-containing protein 3, KISS1, WAP four-disulfide core domain protein 2 (HE4), quiescin sulfhydryl oxidase 2, and pregnancy-specific beta-1-glycoprotein 1.

CONCLUSION

Performance of commercially available enzyme-linked immunosorbent assays was acceptable for a panel of novel biomarkers to predict early pregnancy outcome. Of these, six and seven candidates demonstrated good discriminatory capacity of pregnancy location and viability, respectively, when validated in a distinct external population. Four markers demonstrated good discrimination for both location and viability.

The relationship between serum thiol levels and thiol/disulfide homeostasis in women with tubal ectopic pregnancy

OBJECTIVE

The aim of this study was to investigate the thiol/disulfide homeostasis in tubal ectopic pregnancies in terms of early diagnosis of the disease.

DESIGN

A prospective case-control study was carried out between June 2017-February 2018 in the Gynaecology Department of Umraniye Medical and Research Hospital.

MATERIALS AND METHODS

A total of 42 women with ectopic pregnancy were compared with 44 healthy women who have intrauterine first trimester pregnancies. The thiol/disulfide homeostasis is evaluated with the spectrophotometric measurement method that was recently developed by Erel&Neselioglu.

RESULTS

Disulfide/native thiol and disulfide/total thiol ratios were increased (p = 0.018 and p = 0.023 respectively), while native thiol/total thiol ratios and native thiol levels were decreased in tubal ectopic pregnancy group according to control group (p = 0.023). Between control and tubal ectopic pregnancy groups no differences were measured in disulfide levels (p = 0.350). The area under curve for native thiol and total thiol were 0.937 and 0.927, respectively. The optimum cut off value for native thiol was 379.95 μmol/l with a sensitivity of 90% and specificity of 81%. The optimum cut off value for total thiol was 432.5 μmol/l had 92% sensitivity and 79% specificity.

LIMITATIONS

In the study, whether intrauterine pregnancies resulted in miscarriage or delivery can be examined.

CONCLUSION

Increased disulfide/native thiol levels, disulfide/total-thiol ratio and decreased native/total thiol ratio were found to be significantly associated with the presence of tubal ectopic pregnancy which can be useful for the early diagnosis of the disease.

Cannabinoid receptor type-1 and its correlation with CB1 gene polymorphism-1359G/A in ectopic pregnancy compared to the control group

AIM

Ectopic pregnancy (EP) is one of the most important causes of maternal mortality. This study aimed to evaluate the immunohistochemical (IHC) expression of the cannabinoid receptor type-1 (CB1) and its association with CB1-1359G/A gene polymorphism (rs1049353) in the fallopian tubes in EP compared to controls.

METHODS

In this case-control study, 100 women with EP (cases) and 100 women that underwent abdominal surgery due to the hysterectomy or uterine tubal ligation (healthy controls) were included. Genotyping of CB1-1359G/A polymorphism, tissue expression of CB1 at the protein and mRNA levels were studied using restriction fragment length polymorphism, IHC method, and quantitative real-time polymerase chain reaction (qRT-PCR) analysis.

RESULTS

Genotyping showed that in EP, the frequency of AA, AA+AG genotypes, and A allele was significantly higher than healthy control subjects (p = 0.001). Also, patients with EP had significantly increased IHC expression of CB-1 compared to the control samples (p = 0.016). Patients with AA and AG genotypes had a significantly higher IHC expression of CB-1 compared to the GG genotype. qRT-PCR analysis showed that patients with EP had significantly increased expression of CB-1 compared to the control samples (p < 0.001). Patients with AA and AG genotypes had higher significant mRNA expression of CB-1 compared to the GG genotype.

CONCLUSIONS

CB1 is likely to be effective in creating innate immunity in humans and can affect the process of EP in the fallopian tube. CB1 is also a pathological valuable factor in identifying the pathway of inflammation during ectopic implantation.

Association of Low Maternal Pregnancy-associated Plasma Protein A with Adverse Perinatal Outcome

The aim is to provide an overall view of the association of low pregnancy-associated plasma protein A (PAPP-A) levels with adverse perinatal outcomes. The available literature in PubMed/Medline regarding PAPP-A and adverse pregnancy outcomes was searched for related articles, including terms such as “PAPP-A,” “intrauterine growth restriction (IUGR),” “small for gestational age (SGA),” “stillbirth,” “adverse outcome,” and others. The fifth percentile is supported by many recent studies to be PAPP-A’s cutoff for adverse outcome detection and the increased risk seems to be extremely high below 0.2 PAPP-A MoM (multiple of the median). Apart from chromosomal abnormalities, preeclampsia, intrauterine fetal demise, and pregnancy loss have been associated with maternal serum PAPP-A. For results below the first centile, PAPP-A has a strong positive predictive value for SGA and IUGR. Except for its vital role on the cleavage of insulin-like growth factor binding proteins (IGFBP), PAPP-A has proven to be a reliable marker for prenatal screening. Even though PAPP-A as a single predictor proved to be valuable for the prediction of some adverse perinatal outcomes, in some cases, a combination of PAPP-A to other maternal serum markers led to an increase in detection rates. PAPP-A is a promising maternal serum marker for pregnancy outcome prediction with more studies needed in order for its potentials to be fully understood and exploited.

Evaluation of maternal serum ischemia modified albumin and total antioxidant status in ectopic pregnancy

BACKGROUND

Ectopic pregnancies constitute about 2% of all pregnancies which are the leading cause of pregnancy-related deaths and a considerable cause of maternal morbidity. Oxidative stress can lead to a number of pregnancy related diseases including miscarriage, eclampsia and preterm labor. Ischemia modified albumin (IMA) which reflects the oxidative stress may be used as a marker for ectopic pregnancy. Our aim was to compare the levels of IMA and total antioxidant status (TAS) in ectopic and normal pregnancies and to understand if IMA can be used as a marker to diagnose ectopic pregnancy.

MATERIALS AND METHODS

Our case-control study consisted of 38 women with ectopic and 42 women with normal pregnancy. IMA and TAS levels were determined in serum samples with an albumin-cobalt binding test and by commercially available kits, respectively. IMA levels were adjusted according to serum albumin levels. Index of oxidation (IOS) was calculated by dividing adjusted IMA (A-IMA) levels with TAS. A receiver operating characteristics (ROC) curve analysis was made and cut-off values for the biomarkers were investigated in SPSS 21.0 program (SPSS, Chicago, IL). Data were presented as mean ± standard deviation and a p value < .05 was accepted as statistically significant.

RESULTS

There was a statistically significant difference in IMA, A-IMA, and IOS levels between ectopic and normal pregnancies. Although TAS level was not different statistically, it was lower in ectopic pregnancy. According to ROC curve analysis, IOS had the largest area under curve. A cut-off value of 0.545 for IOS had 81.6% sensitivity and 59.5% specificity.

CONCLUSIONS

According to our study, oxidative stress plays an important role in ectopic pregnancy and either A-IMA or IOS can be evaluated as a marker of ectopic pregnancy after further studies.

No increase in free fetal DNA level in ectopic pregnancy: A preliminary study

Objective:

The aim of this study was to diagnose ectopic pregnancy in the early period by measuring cell-free fetal DNA (cffDNA) levels in maternal blood using spectrophotometry.

Materials and Methods:

Thirty patients with ectopic pregnancy and 30 patients with first trimester intrauterine pregnancy were enrolled in this prospective controlled study. cffDNA levels in maternal serum were measured using spectrophotometry.

Results:

There were no differences between the two groups in terms of cffDNA absorbance levels.

Conclusion:

Spectrophotometry is not suitable for measuring cffDNA levels to diagnose ectopic pregnancies in the early period. Practical and cost-effective methods should be found or larger patient series should be investigated.

Ratios of biochemical markers in peritoneal fluid to those in venous blood for the diagnosis of ruptured tubal pregnancy: A prospective study

OBJECTIVES

Ectopic pregnancies are among the leading causes of maternal morbidity and mortality in both developed and emerging nations, but tests for early, accurate, and convenient detection are lacking.

STUDY DESIGN

Between January 2013 and February 2015, 504 women with tubal pregnancy were prospectively recruited, and their clinical characteristics were recorded. Samples of peritoneal fluid were collected by culdocentesis, and venous blood was drawn from the antecubital vein. In samples from each source, levels of the following biochemical markers were measured: cancer antigen 125 (CA125), human chorionic gonadotropin (hCG), progesterone, vascular endothelial growth factor, and creatine kinase.

RESULTS

The ratios of biochemical markers in the peritoneal fluid and in the blood (R_p/v) were calculated. The median of R_p/v-CA125 and R_p/v-hCG were significantly lower in the ruptured ectopic pregnancy group than in the unruptured group. The optimal cutoff value to detect ectopic pregnancy rupture was 401.5U/mL as the upper limit for peritoneal CA125, with a sensitivity of 93.5% and specificity of 74.2%. The optimal cutoff value was 18.7 as the upper limit in the peritoneal fluid/blood ratio (R_p/v) of CA125, with a sensitivity of 77.5% and specificity of 68.4%.

CONCLUSIONS

In countries with poor access to laparoscopy, culdocentesis is useful. In this study, culdocentesis provided additional information for management of abdominal pain when laparoscopy is not available. The authors propose R_p/v cutoff values that can be used conveniently and quickly to diagnose ruptured ectopic pregnancies and bleeding, enabling rapid and appropriate therapeutic responses.

Predicting first trimester pregnancy outcome: derivation of a multiple marker test

OBJECTIVE

To predict first trimester pregnancy outcome using biomarkers in a multicenter cohort.

DESIGN

Case-control study.

SETTING

Three academic centers.

PATIENT(S)

Women with pain and bleeding in early pregnancy.

INTERVENTION(S)

Sera from women who were 5-12 weeks' gestational age with ectopic pregnancy (EP), viable intrauterine pregnancy (IUP), and miscarriage/spontaneous abortion (SAB) was analyzed by ELISA and immunoassay for activin A, inhibin A, P, A Disintegrin And Metalloprotease-12, pregnancy-associated plasma protein A (PAPP-A), pregnancy specific B1-glycoprotein (SP1), placental-like growth factor, vascular endothelial growth factor, glycodelin (Glyc), and hCG. Classification trees were developed to optimize sensitivity/specificity for pregnancy location and viability.

MAIN OUTCOME MEASURE(S)

Area under receiver operating characteristic curve, sensitivity, specificity, and accuracy of first trimester pregnancy outcome.

RESULT(S)

In 230 pregnancies, the combination of trees to maximize sensitivity and specificity resulted in 73% specificity (95% confidence interval (CI) 0.65-0.80) and 31% sensitivity (95% CI 0.21-0.43) for viability. Similar methods had 21% sensitivity (95% CI 0.12-0.32) and 33% specificity (95% CI 0.26-0.41) for location. Activin A, Glyc, and A Disintegrin And Metalloprotease-12 definitively classified pregnancy location in 29% of the sample with 100% accuracy for EP. Progesterone and PAPP-A classified the viability in 61% of the sample with 94% accuracy.

CONCLUSION(S)

Multiple marker panels can distinguish pregnancy location and viability in a subset of women at risk for early pregnancy complications. This strategy of combining markers to maximize sensitivity and specificity results in high accuracy in a subset of subjects. Activin A, ADAM12, and Glyc are the most promising markers for pregnancy location; P and PAPP-A for viability.

Does adenosine deaminase activity play a role in the early diagnosis of ectopic pregnancy?

Early diagnosis of ectopic pregnancy (EP) is important due to life-threatening consequences in the first trimester of pregnancy. In this study we aimed to investigate the role of adenosine deaminase (ADA) activity in the prediction of EP. Forty-one patients with unruptured ectopic pregnancy comprised the case group and forty-two first trimester pregnant women with shown foetal heart beating in ultrasound comprised the control group. The mean ADA level in EP (10.9 ± 3.0 IU/L) was higher than that in control group (9.2 ± 3.6 IU/L) (p = 0.018). Receiver operating characteristics or ROC curve identified ADA value of 10.95 IU/L as optimal threshold for the prediction of EP with 56% sensitivity and 67% specificity. High ADA levels are valuable in the early diagnosis of EP. However more comprehensive studies are required.

Molecular diagnostics and therapeutics for ectopic pregnancy

Ectopic pregnancies are a serious gynaecological emergency that can be fatal. As such, prompt diagnosis and safe timely treatment is essential. Here, we review the literature on the development of molecularly targeted diagnostics and therapeutics for ectopic pregnancy. A blood-based biomarker that accurately identifies an ectopic pregnancy could be used to offer early diagnostic certainty in cases where ultrasound cannot determine the location of the embryo ('a pregnancy of unknown location'). Molecules examined so far can be broadly grouped into biological themes of relevance to reproduction: (i) Fallopian tube (dys)function, (ii) embryo/trophoblast growth, (iii) corpus luteum function, (iv) inflammation, (v) uterine function and (vi) angiogenesis. While a sensitive and specific biomarker for ectopic pregnancy has yet to be identified, it is possible that improvements in platform technologies or a multi-modal biomarker approach may yield an accurate diagnostic biomarker test. Furthermore, with the advent of better imaging technology, the need for a blood-based biomarker test may be superseded by improvements in ultrasound or magnetic resonance imaging technology. There have been some recent preclinical studies describing molecularly targeted therapeutic approaches for ectopic pregnancy. Notably, bench-to-bedside studies have examined the use of combination gefitinib (orally available epidermal growth factor receptor inhibitor) and methotrexate. Preclinical studies suggest that combination gefitinib and methotrexate is highly effective in inducing placental cell death, and is significantly more effective than methotrexate alone. In early human trials, encouraging preliminary efficacy data have shown that combination gefitinib and methotrexate can rapidly resolve tubal ectopic pregnancies, and large extra-tubal ectopic pregnancies. If a large clinical randomized controlled trial confirms these findings, combination gefitinib and methotrexate could become a new medical treatment option for ectopic pregnancy.

Activin A and follistatin as biomarkers for ectopic pregnancy and missed abortion

Activin A as a predictor of pregnancy failure has been the focus of heated debate, but the value of a combined activin A and follistatin (FS) measurement in serum to predict pregnancy failure has not been reported yet. We assessed whether a single serum measurement of the two physiological antagonists at 6–8 weeks gestation could differentiate ectopic pregnancies (EP) or missed abortions (MA) from healthy intrauterine pregnancies (IUP). activin A concentrations were significantly lower in women with EP (n = 30, median value of 264 pg/mL) and women with MA (n = 30, median value of 350 pg/mL) compared to IUP (n = 33, median value of 788 pg/mL); P < 0.001. At a threshold value of 505 pg/mL, activin A had 87.9% sensitivity and 100% specificity and negative predictive value of 0.974 for discriminating an ectopic pregnancy from viable pregnancies. FS was able to discriminate IUP from EP (ROC curve P < 0.001) as was their ratio (ROC curve P = 0.008), but was unable to discriminate a MA from an EP. In EP, activin A did not correlate with beta HCG levels. The present findings support the thesis that activin A or FS could be considered promising biomarkers for the discrimination between an IUP and a failed pregnancy (MA or EP).

Ectopic pregnancy: a review

PURPOSE

Ectopic pregnancy (EP) presents a major health problem for women of child-bearing age. EP refers to the pregnancy occurring outside the uterine cavity that constitutes 1.2-1.4 % of all reported pregnancies. All identified risk factors are maternal: pelvic inflammatory disease, Chlamydia trachomatis infection, smoking, tubal surgery, induced conception cycle, and endometriosis. These developments have provided the atmosphere for trials using methotrexate as a non-surgical treatment for EP. The diagnosis measure of EP is serum human chorionic gonadotropin, urinary hCGRP/i-hCG, progesterone measurement, transvaginal ultrasound scan, computed tomography, vascular endothelial growth factor, CK, disintegrin and metalloprotease-12 and hysterosalpingography. The treatment option of EP involves surgical treatment by laparotomy or laparoscopy, medical treatment is usually systemic or through local route, or by expectant treatment.

RESULTS

It was concluded that review data reflect a decrease in surgical treatment and not an actual decline in EP occurrence so that further new avenues are needed to explore early detection of the EP.

Maternal Serum Macrophage Inhibitory Cytokine-1 as a Biomarker for Ectopic Pregnancy in Women with a Pregnancy of Unknown Location

BACKGROUND

Ectopic pregnancy (EP) occurs in 1-2% of pregnancies, but is over-represented as a leading cause of maternal death in early pregnancy. It remains a challenge to diagnose early and accurately. Women often present in early pregnancy with a 'pregnancy of unknown location' (PUL) and the diagnosis and exclusion of EP is difficult due to a lack of reliable biomarkers. A serum biomarker able to clearly distinguish between EP and other pregnancy outcomes would greatly assist clinicians in diagnosing and safely managing PULs. This study evaluates the ability of maternal serum macrophage inhibitory cytokine-1 (MIC-1) levels to differentiate between EP and other pregnancy outcomes in women with a PUL.

METHODS

Sera were collected from 120 women with a PUL at first clinical presentation and assayed for MIC-1 by ELISA. Results were classified according to ultimate pregnancy outcome and the discriminatory ability of MIC-1 to diagnose EP was assessed.

RESULTS

Serum MIC-1 levels were lower in women with histologically confirmed (definite) EP (dEP) (median 552 ng/mL; interquartile range (IQR) 414-693 ng/mL) compared to women with definite viable intra-uterine pregnancies (dVIUPs) (722 ng/mL; IQR 412-1122 ng/mL), and higher when compared to women with definite non-viable intra-uterine pregnancies (dNVIUPs) (465 ng/mL; IQR 341-675 ng/mL). MIC-1 levels were significantly higher in women with dEP compared to women whose PULs resolved without medical intervention (srPUL) (401 ng/mL; IQR 315-475 ng/mL) (p<0.003). There were no women with an ectopic pregnancy where serum MIC-1>1000 ng/mL.

CONCLUSION

Serum MIC-1 levels in PUL were not able to categorically diagnose EP, however, MIC-1 could distinguish women with an EP that required medical intervention and those women whose PULs spontaneously resolved. A single serum MIC-1 measurement also excluded EP at levels above 1000 ng/mL. MIC-1 may play a role in the development of a combined assay of biomarkers for the diagnosis of EP.

Comparison of the diagnostic values of circulating steroid hormones, VEGF-A, PIGF, and ADAM12 in women with ectopic pregnancy

Background

Several peripheral proteins that might be useful for detecting the presence of ectopic pregnancy (EP) have been evaluated, but none have been proven entirely useful in the clinic. We investigated the presence and the possible changes in circulating molecules that distinguish between normal intrauterine pregnancy (IUP) and tubal ectopic pregnancy.

Methods

Non-pregnant women during the menstrual cycle, women with IUP, and women with tubal EP after informed consent. Serum levels of 17β-estradiol (E2), progesterone (P4), testosterone (T), beta-human chorionic gonadotropin (β-hCG), vascular endothelial growth factor-A (VEGF-A), placental growth factor (PIGF), and a distintegrin and metalloprotease protein 12 (ADAM12) were analyzed. Receiver operating characteristic analysis was used to assess the diagnostic discrimination of EP and gestational age-matched IUP.

Results

E2, P4, PIGF, and ADAM12 levels increased and β-hCG decreased throughout IUP. E2 and VEGF-A levels were significantly different between women with tubal EP and IUP. However, using a serum β-hCG cut-off of less than 1000 mIU/mL, P4 was significantly lower in women with tubal EP compared to IUP. Although E2 was inversely correlated with VEGF-A in women in the early stages of IUP, E2 was not correlated with VEGF-A in women with EP prior to tubal surgery. There were no significant differences in either PIGF or ADAM12 alone between women with tubal EP or IUP. Although no significant correlations were seen between E2 and PIGF or P4 and ADAM12 in women in the early stages of IUP, E2 was positively correlated with PIGF and P4 was positively correlated with ADAM12 in women with EP prior to tubal surgery. Our studies defined associations but not causality.

Conclusions

Individual measurements of serum E2 or VEGF-A levels are strongly related to early pregnancy outcomes for women with IUP and EP, and pregnancy-associated E2 and VEGF-A levels provide diagnostic accuracy for the presence of tubal EP. This study demonstrates that correlation analysis of E2/VEGF-A and E2/PIGF serum levels may be able to distinguish a tubal EP from a normal IUP.

Interleukin-15 (IL-15) and anti-C1q antibodies as serum biomarkers for ectopic pregnancy and missed abortion

Given the present lack of clinically useful tests for the accurate diagnosis of ectopic pregnancy (EP), there is a need to select out those immunological factors measured in the maternal serum, as potential biomarkers. Our assumption was that C1q/anti-C1q antibody complexes and serum levels of interleukin-15 (IL-15) may play a role in differentiating abortions (MAs) and EPs and normal pregnancies. We assessed whether their measurement could set the diagnosis in a case control study at 6–8 weeks consisting of 60 women with failed early pregnancy (30 EPs, 30 MAs) and 33 women with intrauterine pregnancies. Normal pregnancies contain anti-C1q antibodies more frequently compared to women with failed pregnancies, the lowest levels being found in EPs, but this lacked statistical significance and anti-C1q could not serve as a marker. However EP pregnancies had elevated IL-15 levels that could statistically significantly differentiate them from MAs and IUPs. Furthermore, when assessing IL-15 for the clinically important differentiation between IUP and EP, we found at a cut-off of 16 pg/mL a negative predictive value of 99 with a sensitivity for diagnosing an EP of 92%. According to these results, serum IL-15 is a promising marker differentiating an MA from an EP.

Biomarkers for ectopic pregnancy and pregnancy of unknown location

Early pregnancy failure is the most common complication of pregnancy, and 1% to 2% of all pregnancies will be ectopic. As one of the leading causes of maternal morbidity and mortality, diagnosing ectopic pregnancy and determining the fate of a pregnancy of unknown location are of great clinical concern. Several serum and plasma biomarkers for ectopic pregnancy have been investigated independently and in combination. The following is a review of the state of biomarker discovery and development for ectopic pregnancy and pregnancy of unknown location.

Angiopoietin-1 and angiopoietin-2 as serum biomarkers for ectopic pregnancy and missed abortion: a case-control study

BACKGROUND

A case-control study to evaluate whether a single serum measurement of angiopoietin-1 (ANG-1) and angiopoietin-2 (ANG-2) at 6-8 weeks gestation can differentiate failed pregnancies, whether ectopic pregnancies (EP) or missed abortions (MA), from healthy intrauterine pregnancies (IUP).

INTERVENTION(S)

Serum and tissue mRNA determination of ANG-1 and ANG-2 levels by ELISA and RTPCR, from 60 (30 EP and 30 MA) patients with failed early pregnancy and 33 IUPs.

RESULTS

ANG-1 and ANG-2 concentrations and their ratio are lower in EP (median, 689 and 302 pg/ml, respectively) and MA cases (median, 810 and 402 pg/ml, respectively) compared to IUP (median, 963 and 1477 pg/ml, respectively) (p<0.05, for all). Unlike ANG-2, serum ANG-1 discriminates an EP from a MA (p=0.011). Trophoblastic ANG-1 mRNA expression levels are lower in EP compared to MA and IUP (p<0.05), while ANG-2 mRNA is higher in EP and MA than in IUP (p<0.05).

CONCLUSIONS

A single measurement of serum ANG-1 and ANG-2 at 6-8 weeks of gestation designate the outcome of a pregnancy, as their levels are significantly decreased in failed than normal pregnancies. Serum ANG-1 showed potential to discriminate MA from EP.

Increased expression of the von Hippel-Lindau gene in the implantation site of human tubal pregnancy

The objective of this study was to investigate the expression of the von Hippel-Lindau (VHL) gene in tissues of human fallopian tube and tubal pregnancy. Twenty patients undergoing salpingectomy for tubal pregnancy were recruited into the study group. Tissues of tubal pregnancy were separated into both the implantation and non-implantation sites as the implantation group and the non-implantation group, respectively. Samples of ampullary fallopian tube during mid-secretory phase were collected from twenty patients with benign uterine disease as the control group. Immunohistochemistry, real-time reverse transcription polymerase chain reaction, and Western blotting analysis were performed to detect expressions of VHL mRNA and protein. The results showed that VHL immunostaining appeared in the cytoplasm of tubal epithelial cells. Expression of VHL mRNA in the implantation group was higher than that in the non-implantation group or the control group (P < 0.01). Intensity of VHL protein in the implantation group was increased compared with that in the non-implantation group (P < 0.05) or in the control group (P < 0.01). There was no difference on expressions of VHL mRNA and protein between the non-implantation group and the control group (P > 0.05). In conclusion, VHL mRNA and protein are present in human tubal tissues. The VHL gene expression is increased in the implantation site of tubal pregnancy, and locally elevated expression of the VHL gene might be associated with human tubal pregnancy.

Systematic discovery of ectopic pregnancy serum biomarkers using 3-D protein profiling coupled with label-free quantitation

Ectopic pregnancy (EP) and normal intrauterine pregnancy (IUP) serum proteomes were quantitatively compared to systematically identify candidate biomarkers. A 3-D biomarker discovery strategy consisting of abundant protein immunodepletion, SDS gels, LC-MS/MS, and label-free quantitation of MS signal intensities identified 70 candidate biomarkers with differences between groups greater than 2.5-fold. Further statistical analyses of peptide quantities were used to select the most promising 12 biomarkers for further study, which included known EP biomarkers, novel EP biomarkers (ADAM12 and ISM2), and five specific isoforms of the pregnancy specific beta-1-glycoprotein family. Technical replicates showed good reproducibility and protein intensities from the label-free discovery analysis compared favorably with reported abundance levels of several known reference serum proteins over at least 3 orders of magnitude. Similarly, relative abundances of candidate biomarkers from the label-free discovery analysis were consistent with relative abundances from pilot validation assays performed for five of the 12 most promising biomarkers using label-free multiple reaction monitoring of both the patient serum pools used for discovery and the individual samples that constituted these pools. These results demonstrate robust, reproducible, in-depth 3-D serum proteome discovery, and subsequent pilot-scale validation studies can be achieved readily using label-free quantitation strategies.

Association study of vascular endothelial growth factor and polymorphisms of its gene with ectopic pregnancy

PROBLEM

In ectopic pregnancy, increased levels of vascular endothelial growth factor are present. The aims of this study were to determine the association between -634C/G, -460T/C, and +936C/T vascular endothelial growth factor (VEGF) polymorphisms and ectopic pregnancy, and to determine whether serum levels of VEGF were affected by genetic factors.

METHOD

of study This is a case-control study wherein 74 women with a history of ectopic pregnancy in a tertiary care center were compared to 134 post-menopausal controls with two pregnancies and no ectopic pregnancy for the genotyping of VEGF polymorphisms. For 35 patients with the diagnosis of ectopic pregnancy, serum concentrations of VEGF were obtained before the treatment. Genotyping of VEGF (-634C/G, -460T/C, and +936C/T) polymorphisms was performed by PCR, followed by endonuclease digestion. ELISA was performed to evaluate the VEGF serum levels.

RESULTS

The -634C/G, -460T/C, and +936C/T VEGF polymorphisms were not associated with ectopic pregnancy (P = 0.170, P = 0.285, and P = 0.700, respectively). The serum levels of VEGF were not associated with the genotype of -634C/G, -460T/C, and +936C/T VEGF polymorphisms (P = 0.702; P = 0.347, and P = 0.256, respectively).

CONCLUSION

There was no association between ectopic pregnancy and -634C/G, -460T/C, and +936C/T VEGF polymorphisms. There was no correlation between VEGF genotype and the expression of VEGF in blood samples.

Serum biomarkers of tubal ectopic pregnancy: current candidates and future possibilities

Ectopic pregnancy remains a considerable cause of maternal morbidity and mortality worldwide. Currently, it is diagnosed using a combination of transvaginal ultrasound and serial serum beta-human chorionic gonadotrophin levels. Diagnosis is often delayed and these tests are time-consuming and costly, both psychologically to the patient and financially to health services. The development of a biomarker that can differentiate a tubal ectopic from an intrauterine implantation is therefore important. In the pre-genomic era, a one-by-one scientific approach has revealed over 20 candidate biomarkers that could be used as a test to diagnose ectopic pregnancy although at present their clinical utility is very limited. These biomarkers cluster into themes: markers of abnormal embryo/trophoblast growth, markers of abnormal corpus luteum function, markers of a growing pregnancy in the Fallopian tube, markers of inflammation and peritoneal irritation, and uterine markers of normal implantation. It is likely that this thematic approach will facilitate the identification of newer biomarkers using microarray technology and inform the development of investigative paradigms using multiple markers at the time of presentation.

Serum markers in the diagnosis of tubal pregnancy

The introduction of highly sensitive methods, such as transvaginal sonography and measurement of serum b-human chorionic gonadotropin, has dramatically improved ectopic pregnancy diagnosis in recent years. Early diagnosis is the key to successful and conservative management of women with ectopic pregnancy; however, approximately 50 percent of such women are initially misdiagnosed, resulting in significant morbidity and mortality. In order to improve diagnosis, several serum markers are being investigated including progesterone, CA 125, pregnancy-associated plasma protein-A, vascular endothelial growth factor, and maternal creatine kinase. Measurement of serum vascular endothelial growth factor, alone or together with other markers, could be a promising method for earlier and more accurate differential diagnosis. However, the clinical applicability of these findings remains to be evaluated in larger prospective studies.

Presence of Cell-Free Fetal DNA in Plasma of Women with Ectopic Pregnancies,

Background: The quantity of cell-free fetal DNA in the plasma of pregnant women changes during pregnancy and seems to be different in normal and pathologic pregnancies. We investigated the possible diagnostic applications of the detection and measurement of cell-free fetal DNA by comparing quantities found in women with ectopic (EP) or intrauterine (IUP) pregnancies.

Methods: We collected blood samples from 58 women who had positive pregnancy tests and specific complaints and sonographic findings suggestive of EP and from 45 women with confirmed IUP. We performed quantitative real-time PCR analysis of the sex-determining region Y (SRY) gene to detect and measure the amount of cell-free fetal DNA. The diagnosis of EP was confirmed by histologic examination.

Results: SRY was detected in 15 EP and 14 IUP cases. The mean (SD) amount of cell-free fetal DNA was significantly higher (P &lt;0.005) in women with EP [565 (136) genome-equivalents (GE)/mL] than in women with IUP [72 (19) GE/mL] at the same gestational age.

Conclusions: Our results confirm that cell-free fetal DNA is present in plasma of women with EP. The finding of higher amounts of cell-free fetal DNA in EP cases than in IUP cases suggests that this method might be useful for early diagnosis of EP.