Journal of Obstetrics and Gynaecology, 2014; 34: 218–220 © 2014 Informa UK, Ltd. ISSN 0144-3615 print/ISSN 1364-6893 online DOI: 10.3109/01443615.2013.834304
OBSTETRICS
Angiogenic growth factors in maternal and fetal serum in pregnancies complicated with intrauterine growth restriction D. Borras1, A. Perales-Puchalt1, N. Ruiz Sacedón2 & A. Perales1,2
J Obstet Gynaecol Downloaded from informahealthcare.com by Nyu Medical Center on 06/17/15 For personal use only.
Department of Obstetrics and Gynecology, 1Hospital Universitario La Fe and 2Hospital Dr Peset, Valencia, Spain
The aim of this paper was to study if soluble fms-like tyrosine kinase 1 (sFlt-1), free vascular endothelial growth factor (f-VEGF) and the f-VEGF/sFlt-1 quotient in singleton pregnancies complicated with intrauterine growth restriction (IUGR) are different from controls. This was a case–control study between 18 pregnancies with IUGR and 24 controls. Angiogenic growth factors were measured in maternal serum during pregnancy and in umbilical artery and vein at birth. Results showed that maternal plasma f-VEGF and s-Flt-1 were significantly higher in IUGR compared with controls (p ⴝ 0.01 and 0.001, respectively). f-VEGF/sFlt-1 quotient was significantly lower in the IUGR group compared with controls. When we analysed umbilical cord angiogenic factors, we found no significant differences in the artery or vein angiogenic growth factors between the IUGR group and controls. It was concluded that mothers of IUGR fetuses have a more anti-angiogenic environment compared to those of controls. Keywords: Angiogenesis, fetal growth restriction, sFlt-1, VEGF
Introduction Intrauterine growth restriction (IUGR) is one of the most important causes of perinatal morbidity and mortality and it is also associated with cerebral palsy and adult diseases (Figueras and Gardosi 2011). Multiple processes have been associated with IUGR, however, others remain unknown (Maulik et al. 2006). Successful pregnancy requires the development of a complex maternal and fetal vascular network to maintain increasing oxygen and metabolic demands of the growing fetus (Jacobs et al. 2011). Angiogenesis plays an important role in the development of IUGR (Gourvas et al. 2012). Free vascular endothelial growth factor (f-VEGF) and soluble fms-like tyrosine kinase 1 (sFlt-1) are involved in the regulation of angiogenesis (Kendall and Thomas 1993). Recent studies have shown that sFlt-1 is increased in the placenta and serum of women with pre-eclampsia (Wathen et al. 2006) and IUGR (Wallner et al. 2007). Our aim was to study sFlt-1, f-VEGF and the f-VEGF/sFlt-1 quotient in IUGR and control singleton pregnancies and to determine if they are different in IUGR than controls.
Materials and methods This was a prospective case–control study. The study participants were healthy women with singleton pregnancies. They were recruited from La Fe University Hospital in Valencia, between October 2006 and October 2007, at the first visit with our unit. The study was approved by the ethical committee of La Fe University Hospital and informed written consent was obtained from all study subjects. We offered participation to all IUGR singleton pregnancies that our team detected during the study period. We defined IUGR as pregnancies with a birth weight below the 10th percentile for gestational age and sex. Controls were singleton pregnancies with a birth weight that was adequate for gestational age. Both cases and controls had the same source population, which is the health department at La Fe University Hospital. Maternal illness, obstetric disorders (diabetes, pre-eclampsia), multiple pregnancies and fetal malformations or stillbirth were considered as exclusion criteria. Gestational age was estimated with a crown-rump length (CRL) during the first trimester and with the measurement of head circumference (HC), abdominal circumference (AC) and femur length (FL) in the second and third trimesters. We used a Voluson® (General Electrics) ultrasound scanner. We collected maternal blood samples from the antecubital vein during pregnancy and at delivery. Fetal blood samples were taken from the umbilical artery and vein immediately after delivery. We centrifuged blood samples immediately at 3,500 g for 5 min. Plasma aliquots were stored at ⫺80°C until VEGF complex analysis. Plasma levels of sFlt-1 and f-VEGF were measured using the sandwich enzyme immunoassay technique (Bender MedSystems, Vienna, Austria). Intra- and inter-assay coefficients of variation were 8% and 10.7% for sFlt-1 and 5.9% and 17.7% for f-VEGF. Sensitivity for f-VEGF and sFlt-1 were 11 pg/ml and 0.06 ng/ml, respectively. Other variables we recorded were: maternal age, gestational age at delivery, type of delivery, birth weight, newborn sex, Apgar score and blood gas analysis. The trimesters of pregnancy were defined first trimester ⱕ 14 weeks, second trimester 15–28 weeks, third trimester ⬎ 28 weeks, in order to have an appropriate number of cases for the analysis. The number of cases in the area during the study period determined the sample size. We used Mann–Whitney U and t-tests for comparing quantitative variables and χ2 and Fisher’s exact tests for qualitative ones. All analyses were two-sided, at a 5% significance level. Analyses
Correspondence: A. Perales-Puchalt, Department of Obstetrics and Gynecology, Hospital Universitario La Fe, Valencia, Spain. Bulevar Sur s/n, 46026, Valencia, Spain. E-mail: [email protected]
Angiogenic growth factors and IUGR 219 Table I. Demographic characteristics and outcomes of the study patients. IUGR (n ⫽ 14)
J Obstet Gynaecol Downloaded from informahealthcare.com by Nyu Medical Center on 06/17/15 For personal use only.
n Maternal age (years) (mean ⫾ SD) Mode of conception Spontaneous ART Way of delivery Vaginal Caesarean section GA at delivery (weeks) (mean ⫾ SD) Birth weight (g) (mean ⫾ SD) Sex Male Female Last UA PI (mean ⫾ SD) Last MCI PI (mean ⫾ SD) Uterine artery PI (mean ⫾ SD) Arterial pH (mean ⫾ SD)
Controls (n ⫽ 28) (%)
n
31.9 ⫾ 5.3 0 0 8 6 35.1 ⫾ 2.3 2297.1 ⫾ 528.9
(%)
30.9 ⫾ 5.7
0.477
100 0
25 1
57.1 42.9
14 14 36.3 ⫾ 2.1 3467.9 ⫾ 374.1
6 8 1.15 ⫾ 0.31 1.79 ⫾ 0.42 1.00 ⫾ 0.41 7.28 ⫾ 0.04
p value
96.4 3.6 50 50
15 13 0.90 ⫾ 0.15 1.60 ⫾ 0.50 0.74 ⫾ 0.26 7.25 ⫾ 0.07
1
0.662 0.045 ⬍ 0.001
0.749 0.007 0.167 0.011 0.534
Mann–Whitney U test for continuous variables, χ2 or Fisher’s exact tests for qualitative variables. GA, gestational age; PI, pulsatility index; UA, umbilical artery; MCA, medial cerebral artery. Doppler examinations were performed in 13 IUGR and 23 controls.
were done with SPSS 15.0. Missing data were excluded from the analysis.
Results Participants We included in the study 42 patients, 18 cases and 24 controls. The demographic characteristics and outcomes are shown in Table I. There were no differences in maternal age, mode of conception, parity and mode of delivery. The IUGR group delivered, on average, a week before the control group and had a significantly higher last umbilical artery pulsatility index (PI) and a higher uterine artery PI. There were no differences in medial cerebral artery Dopplers and arterial pH.
Maternal angiogenic growth factors The mean maternal plasma concentration for f-VEGF, sFlt-1 and f-VEGF/sFlt-1 stratified per trimester of pregnancy are shown in Table II. Maternal plasma f-VEGF and s-Flt-1 were significantly Table II. Basal circulating plasma angiogenic growth factor and receptor concentrations stratified by trimester of pregnancy. IUGR (mean ⫾ SD) f-VEGF (pg/ml) first trimester (1 vs 9) second trimester (7 vs 21) third trimester (14 vs 35) Total s-Flt-1 (pg/ml) first trimester (1 vs 9) second trimester (7 vs 21) third trimester (14 vs 35) Total f-VEGF/s-Flt-1 first trimester (1 vs 9) second trimester (7 vs 21) third trimester (14 vs 35) Total Mann–Whitney U test.
Controls (mean ⫾ SD)
higher in IUGR compared with controls (p ⫽ 0.01 and 0.001, respectively). f-VEGF/sFlt-1 quotient was significantly lower in the IUGR group compared with controls. When we stratified per trimester of pregnancy, these results were constant, although not always significant. We found a significant negative correlation between gestational age and f-VEGF/sFlt-1 (r ⫽ ⫺0.429, p ⫽ 0.01), and a positive correlation with sFlt-1 (r ⫽ 0.536, p ⬍ 0.01) in controls. No correlations with gestational age were found in the IUGR group. We found significant negative correlations between placental weight and f-VEGF (r ⫽ ⫺0.613, p ⫽ 0.01) in controls, and birth weight and sFlt-1 (r ⫽ ⫺0.631, p ⫽ 0.05) in cases. We found no significant correlation between other maternal angiogenic growth factors and placental or fetal weight.
Fetal angiogenic growth factors The mean arterial and venous umbilical cord concentration for f-VEGF, sFlt-1 and f-VEGF/sFlt-1 are shown in Table III. There were no significant differences in the artery or vein angiogenic growth factors between the IUGR group and controls. There is no significant correlation between umbilical cord angiogenic growth factors and placental or fetal weight.
p value
Discussion 64.2 92.4 ⫾ 29.6 123.8 ⫾ 64.5 111.1 ⫾ 56.2
87.3 ⫾ 66.5 68.4 ⫾ 41.4 82.7 ⫾ 49.8 78.7 ⫾ 49.6
1 0.055 0.040 0.009
282.0 159.3 ⫾ 66.8 373.3 ⫾ 167.0 301.1 ⫾ 169.5
125.6 ⫾ 96.5 90.2 ⫾ 98.6 208.7 ⫾ 152.5 158.9 ⫾ 140.1
0.200 0.062 0.002 0.001
0.23 0.68 ⫾ 0.33 0.41 ⫾ 0.28 0.49 ⫾ 0.31
2.24 ⫾ 3.19 2.99 ⫾ 3.42 1.21 ⫾ 2.51 1.93 ⫾ 2.99
0.400 0.126 0.493 0.045
We hypothesised that there would be a more anti-angiogenic environment in mothers and fetuses in the IUGR group. Table III. Arterial and venous umbilical plasma angiogenic factors. IUGR (mean ⫾ SD) Controls (mean ⫾ SD) (n ⫽ 9) (n ⫽ 18) p value Arterial f-VEGF (pg/ml) Arterial s-Flt-1 (pg/ml) Arterial f-VEGF/s-Flt-1 Venous f-VEGF (pg/ml) Venous s-Flt-1 (pg/ml) Venous f-VEGF/s-Flt-1 Mann–Whitney U test.
132.2 ⫾ 61.7 83.4 ⫾ 62.8 4.80 ⫾ 5.71 113.8 ⫾ 56.3 78.0 ⫾ 52.6 3.03 ⫾ 4.21
117.6 ⫾ 71.6 49.5 ⫾ 61.4 7.08 ⫾ 6.19 118.3 ⫾ 81.0 96.1 ⫾ 112.4 3.95 ⫾ 3.43
0.571 0.281 0.213 0.959 0.625 0.537
J Obstet Gynaecol Downloaded from informahealthcare.com by Nyu Medical Center on 06/17/15 For personal use only.
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D. Borras et al.
We found that mothers in the IUGR group had lower plasma f-VEGF/sFlt-1, with a higher f-VEGF and an even higher sFlt-1. In agreement, Wallner et al. (2007) found higher maternal sFlt-1 levels in the IUGR group, but no difference in the umbilical artery. Our results are also in agreement with the study by Savvidou et al. (2006), where mothers with IUGR and abnormal uterine artery Doppler had significantly higher levels of sFlt-1 than controls. In contrast with our results, Wathen et al. (2006) found no differences in sFlt-1 in pregnant women with isolated IUGR in the second trimester, compared with normal pregnancies. However, its median was higher than the one of mild pre-eclampsia, which makes us think that a larger sample size would have found significant differences. A limitation to this study is the scarce number of patients, which limits the power of the analysis. This occurs especially in the first trimester and does not allow the study of a possible early detection of IUGR by the study of the angiogenic growth factors. This also limits the control of the confounders. There were a number of patients in both groups with outliers in the angiogenic factors which we could not explain. This enhanced the standard deviation of our data and makes us think that there are important unknown confounders that must be elucidated with further studies. The lower f-VEGF/sFlt-1 quotient in the mothers of IUGR fetuses is probably associated to the lower feto-placental mass in this group. This study has strengths, such as the control of the information bias by performing the same tests on all our patients and running all the analysis at the same time and with the same kits. In conclusion, the mothers of IUGR fetuses have a more antiangiogenic environment, in agreement with the physiological role of the angiogenic factors. However, we are lacking other factors that have a bigger influence on the fetal growth pathogenesis and the angiogenic factors variability.
Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper. This study was supported by a grant from the Spanish Fondo de Investigación Sanitaria (FIS) PI3030059.
References Figueras F, Gardosi J. 2011. Intrauterine growth restriction: new concepts in antenatal surveillance, diagnosis, and management. American Journal of Obstetrics and Gynecology 204:288–300. Gourvas V, Dalpa E, Konstantinidou A, Vrachnis N, Spandidos DA, Sifakis S. 2012. Angiogenic factors in placentas from pregnancies complicated by fetal growth restriction. Molecular Medicine Reports 6:23–27. Jacobs M, Nassar N, Roberts CL, Hadfield R, Morris JM, Ashton AW. 2011. Levels of soluble fms-like tyrosine kinase one in first trimester and outcomes of pregnancy: a systematic review. Reproductive Biology and Endocrinology 9:77. Kendall RL, Thomas KA. 1993. Inhibition of vascular endothelial cell growth factor activity by an endogenously encoded soluble receptor. Proceedings of the National Academy of Sciences of the United States of America 90:10705–10709. Maulik D, Frances Evans J, Ragolia L. 2006. Fetal growth restriction: pathogenic mechanisms. Clinical Obstetrics and Gynecology 49:219–227. Savvidou MD, Yu CK, Harland LC, Hingorani AD, Nicolaides KH. 2006. Maternal serum concentration of soluble fms-like tyrosine kinase 1 and vascular endothelial growth factor in women with abnormal uterine artery Doppler and in those with fetal growth restriction. American Journal of Obstetrics and Gynecology 195:1668–1673. Wallner W, Sengenberger R, Strick R, Strissel PL, Meurer B, Beckmann MW et al. 2007. Angiogenic growth factors in maternal and fetal serum in pregnancies complicated by intrauterine growth restriction. Clinical Science 112:51–57. Wathen KA, Tuutti E, Stenman UH, Alfthan H, Halmesmaki E, Finne P et al. 2006. Maternal serum-soluble vascular endothelial growth factor receptor-1 in early pregnancy ending in preeclampsia or intrauterine growth retardation. Journal of Clinical Endocrinology and Metabolism 91:180–184.
OBSTETRICS
Angiogenic growth factors in maternal and fetal serum in pregnancies complicated with intrauterine growth restriction D. Borras1, A. Perales-Puchalt1, N. Ruiz Sacedón2 & A. Perales1,2
J Obstet Gynaecol Downloaded from informahealthcare.com by Nyu Medical Center on 06/17/15 For personal use only.
Department of Obstetrics and Gynecology, 1Hospital Universitario La Fe and 2Hospital Dr Peset, Valencia, Spain
The aim of this paper was to study if soluble fms-like tyrosine kinase 1 (sFlt-1), free vascular endothelial growth factor (f-VEGF) and the f-VEGF/sFlt-1 quotient in singleton pregnancies complicated with intrauterine growth restriction (IUGR) are different from controls. This was a case–control study between 18 pregnancies with IUGR and 24 controls. Angiogenic growth factors were measured in maternal serum during pregnancy and in umbilical artery and vein at birth. Results showed that maternal plasma f-VEGF and s-Flt-1 were significantly higher in IUGR compared with controls (p ⴝ 0.01 and 0.001, respectively). f-VEGF/sFlt-1 quotient was significantly lower in the IUGR group compared with controls. When we analysed umbilical cord angiogenic factors, we found no significant differences in the artery or vein angiogenic growth factors between the IUGR group and controls. It was concluded that mothers of IUGR fetuses have a more anti-angiogenic environment compared to those of controls. Keywords: Angiogenesis, fetal growth restriction, sFlt-1, VEGF
Introduction Intrauterine growth restriction (IUGR) is one of the most important causes of perinatal morbidity and mortality and it is also associated with cerebral palsy and adult diseases (Figueras and Gardosi 2011). Multiple processes have been associated with IUGR, however, others remain unknown (Maulik et al. 2006). Successful pregnancy requires the development of a complex maternal and fetal vascular network to maintain increasing oxygen and metabolic demands of the growing fetus (Jacobs et al. 2011). Angiogenesis plays an important role in the development of IUGR (Gourvas et al. 2012). Free vascular endothelial growth factor (f-VEGF) and soluble fms-like tyrosine kinase 1 (sFlt-1) are involved in the regulation of angiogenesis (Kendall and Thomas 1993). Recent studies have shown that sFlt-1 is increased in the placenta and serum of women with pre-eclampsia (Wathen et al. 2006) and IUGR (Wallner et al. 2007). Our aim was to study sFlt-1, f-VEGF and the f-VEGF/sFlt-1 quotient in IUGR and control singleton pregnancies and to determine if they are different in IUGR than controls.
Materials and methods This was a prospective case–control study. The study participants were healthy women with singleton pregnancies. They were recruited from La Fe University Hospital in Valencia, between October 2006 and October 2007, at the first visit with our unit. The study was approved by the ethical committee of La Fe University Hospital and informed written consent was obtained from all study subjects. We offered participation to all IUGR singleton pregnancies that our team detected during the study period. We defined IUGR as pregnancies with a birth weight below the 10th percentile for gestational age and sex. Controls were singleton pregnancies with a birth weight that was adequate for gestational age. Both cases and controls had the same source population, which is the health department at La Fe University Hospital. Maternal illness, obstetric disorders (diabetes, pre-eclampsia), multiple pregnancies and fetal malformations or stillbirth were considered as exclusion criteria. Gestational age was estimated with a crown-rump length (CRL) during the first trimester and with the measurement of head circumference (HC), abdominal circumference (AC) and femur length (FL) in the second and third trimesters. We used a Voluson® (General Electrics) ultrasound scanner. We collected maternal blood samples from the antecubital vein during pregnancy and at delivery. Fetal blood samples were taken from the umbilical artery and vein immediately after delivery. We centrifuged blood samples immediately at 3,500 g for 5 min. Plasma aliquots were stored at ⫺80°C until VEGF complex analysis. Plasma levels of sFlt-1 and f-VEGF were measured using the sandwich enzyme immunoassay technique (Bender MedSystems, Vienna, Austria). Intra- and inter-assay coefficients of variation were 8% and 10.7% for sFlt-1 and 5.9% and 17.7% for f-VEGF. Sensitivity for f-VEGF and sFlt-1 were 11 pg/ml and 0.06 ng/ml, respectively. Other variables we recorded were: maternal age, gestational age at delivery, type of delivery, birth weight, newborn sex, Apgar score and blood gas analysis. The trimesters of pregnancy were defined first trimester ⱕ 14 weeks, second trimester 15–28 weeks, third trimester ⬎ 28 weeks, in order to have an appropriate number of cases for the analysis. The number of cases in the area during the study period determined the sample size. We used Mann–Whitney U and t-tests for comparing quantitative variables and χ2 and Fisher’s exact tests for qualitative ones. All analyses were two-sided, at a 5% significance level. Analyses
Correspondence: A. Perales-Puchalt, Department of Obstetrics and Gynecology, Hospital Universitario La Fe, Valencia, Spain. Bulevar Sur s/n, 46026, Valencia, Spain. E-mail: [email protected]
Angiogenic growth factors and IUGR 219 Table I. Demographic characteristics and outcomes of the study patients. IUGR (n ⫽ 14)
J Obstet Gynaecol Downloaded from informahealthcare.com by Nyu Medical Center on 06/17/15 For personal use only.
n Maternal age (years) (mean ⫾ SD) Mode of conception Spontaneous ART Way of delivery Vaginal Caesarean section GA at delivery (weeks) (mean ⫾ SD) Birth weight (g) (mean ⫾ SD) Sex Male Female Last UA PI (mean ⫾ SD) Last MCI PI (mean ⫾ SD) Uterine artery PI (mean ⫾ SD) Arterial pH (mean ⫾ SD)
Controls (n ⫽ 28) (%)
n
31.9 ⫾ 5.3 0 0 8 6 35.1 ⫾ 2.3 2297.1 ⫾ 528.9
(%)
30.9 ⫾ 5.7
0.477
100 0
25 1
57.1 42.9
14 14 36.3 ⫾ 2.1 3467.9 ⫾ 374.1
6 8 1.15 ⫾ 0.31 1.79 ⫾ 0.42 1.00 ⫾ 0.41 7.28 ⫾ 0.04
p value
96.4 3.6 50 50
15 13 0.90 ⫾ 0.15 1.60 ⫾ 0.50 0.74 ⫾ 0.26 7.25 ⫾ 0.07
1
0.662 0.045 ⬍ 0.001
0.749 0.007 0.167 0.011 0.534
Mann–Whitney U test for continuous variables, χ2 or Fisher’s exact tests for qualitative variables. GA, gestational age; PI, pulsatility index; UA, umbilical artery; MCA, medial cerebral artery. Doppler examinations were performed in 13 IUGR and 23 controls.
were done with SPSS 15.0. Missing data were excluded from the analysis.
Results Participants We included in the study 42 patients, 18 cases and 24 controls. The demographic characteristics and outcomes are shown in Table I. There were no differences in maternal age, mode of conception, parity and mode of delivery. The IUGR group delivered, on average, a week before the control group and had a significantly higher last umbilical artery pulsatility index (PI) and a higher uterine artery PI. There were no differences in medial cerebral artery Dopplers and arterial pH.
Maternal angiogenic growth factors The mean maternal plasma concentration for f-VEGF, sFlt-1 and f-VEGF/sFlt-1 stratified per trimester of pregnancy are shown in Table II. Maternal plasma f-VEGF and s-Flt-1 were significantly Table II. Basal circulating plasma angiogenic growth factor and receptor concentrations stratified by trimester of pregnancy. IUGR (mean ⫾ SD) f-VEGF (pg/ml) first trimester (1 vs 9) second trimester (7 vs 21) third trimester (14 vs 35) Total s-Flt-1 (pg/ml) first trimester (1 vs 9) second trimester (7 vs 21) third trimester (14 vs 35) Total f-VEGF/s-Flt-1 first trimester (1 vs 9) second trimester (7 vs 21) third trimester (14 vs 35) Total Mann–Whitney U test.
Controls (mean ⫾ SD)
higher in IUGR compared with controls (p ⫽ 0.01 and 0.001, respectively). f-VEGF/sFlt-1 quotient was significantly lower in the IUGR group compared with controls. When we stratified per trimester of pregnancy, these results were constant, although not always significant. We found a significant negative correlation between gestational age and f-VEGF/sFlt-1 (r ⫽ ⫺0.429, p ⫽ 0.01), and a positive correlation with sFlt-1 (r ⫽ 0.536, p ⬍ 0.01) in controls. No correlations with gestational age were found in the IUGR group. We found significant negative correlations between placental weight and f-VEGF (r ⫽ ⫺0.613, p ⫽ 0.01) in controls, and birth weight and sFlt-1 (r ⫽ ⫺0.631, p ⫽ 0.05) in cases. We found no significant correlation between other maternal angiogenic growth factors and placental or fetal weight.
Fetal angiogenic growth factors The mean arterial and venous umbilical cord concentration for f-VEGF, sFlt-1 and f-VEGF/sFlt-1 are shown in Table III. There were no significant differences in the artery or vein angiogenic growth factors between the IUGR group and controls. There is no significant correlation between umbilical cord angiogenic growth factors and placental or fetal weight.
p value
Discussion 64.2 92.4 ⫾ 29.6 123.8 ⫾ 64.5 111.1 ⫾ 56.2
87.3 ⫾ 66.5 68.4 ⫾ 41.4 82.7 ⫾ 49.8 78.7 ⫾ 49.6
1 0.055 0.040 0.009
282.0 159.3 ⫾ 66.8 373.3 ⫾ 167.0 301.1 ⫾ 169.5
125.6 ⫾ 96.5 90.2 ⫾ 98.6 208.7 ⫾ 152.5 158.9 ⫾ 140.1
0.200 0.062 0.002 0.001
0.23 0.68 ⫾ 0.33 0.41 ⫾ 0.28 0.49 ⫾ 0.31
2.24 ⫾ 3.19 2.99 ⫾ 3.42 1.21 ⫾ 2.51 1.93 ⫾ 2.99
0.400 0.126 0.493 0.045
We hypothesised that there would be a more anti-angiogenic environment in mothers and fetuses in the IUGR group. Table III. Arterial and venous umbilical plasma angiogenic factors. IUGR (mean ⫾ SD) Controls (mean ⫾ SD) (n ⫽ 9) (n ⫽ 18) p value Arterial f-VEGF (pg/ml) Arterial s-Flt-1 (pg/ml) Arterial f-VEGF/s-Flt-1 Venous f-VEGF (pg/ml) Venous s-Flt-1 (pg/ml) Venous f-VEGF/s-Flt-1 Mann–Whitney U test.
132.2 ⫾ 61.7 83.4 ⫾ 62.8 4.80 ⫾ 5.71 113.8 ⫾ 56.3 78.0 ⫾ 52.6 3.03 ⫾ 4.21
117.6 ⫾ 71.6 49.5 ⫾ 61.4 7.08 ⫾ 6.19 118.3 ⫾ 81.0 96.1 ⫾ 112.4 3.95 ⫾ 3.43
0.571 0.281 0.213 0.959 0.625 0.537
J Obstet Gynaecol Downloaded from informahealthcare.com by Nyu Medical Center on 06/17/15 For personal use only.
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D. Borras et al.
We found that mothers in the IUGR group had lower plasma f-VEGF/sFlt-1, with a higher f-VEGF and an even higher sFlt-1. In agreement, Wallner et al. (2007) found higher maternal sFlt-1 levels in the IUGR group, but no difference in the umbilical artery. Our results are also in agreement with the study by Savvidou et al. (2006), where mothers with IUGR and abnormal uterine artery Doppler had significantly higher levels of sFlt-1 than controls. In contrast with our results, Wathen et al. (2006) found no differences in sFlt-1 in pregnant women with isolated IUGR in the second trimester, compared with normal pregnancies. However, its median was higher than the one of mild pre-eclampsia, which makes us think that a larger sample size would have found significant differences. A limitation to this study is the scarce number of patients, which limits the power of the analysis. This occurs especially in the first trimester and does not allow the study of a possible early detection of IUGR by the study of the angiogenic growth factors. This also limits the control of the confounders. There were a number of patients in both groups with outliers in the angiogenic factors which we could not explain. This enhanced the standard deviation of our data and makes us think that there are important unknown confounders that must be elucidated with further studies. The lower f-VEGF/sFlt-1 quotient in the mothers of IUGR fetuses is probably associated to the lower feto-placental mass in this group. This study has strengths, such as the control of the information bias by performing the same tests on all our patients and running all the analysis at the same time and with the same kits. In conclusion, the mothers of IUGR fetuses have a more antiangiogenic environment, in agreement with the physiological role of the angiogenic factors. However, we are lacking other factors that have a bigger influence on the fetal growth pathogenesis and the angiogenic factors variability.
Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper. This study was supported by a grant from the Spanish Fondo de Investigación Sanitaria (FIS) PI3030059.
References Figueras F, Gardosi J. 2011. Intrauterine growth restriction: new concepts in antenatal surveillance, diagnosis, and management. American Journal of Obstetrics and Gynecology 204:288–300. Gourvas V, Dalpa E, Konstantinidou A, Vrachnis N, Spandidos DA, Sifakis S. 2012. Angiogenic factors in placentas from pregnancies complicated by fetal growth restriction. Molecular Medicine Reports 6:23–27. Jacobs M, Nassar N, Roberts CL, Hadfield R, Morris JM, Ashton AW. 2011. Levels of soluble fms-like tyrosine kinase one in first trimester and outcomes of pregnancy: a systematic review. Reproductive Biology and Endocrinology 9:77. Kendall RL, Thomas KA. 1993. Inhibition of vascular endothelial cell growth factor activity by an endogenously encoded soluble receptor. Proceedings of the National Academy of Sciences of the United States of America 90:10705–10709. Maulik D, Frances Evans J, Ragolia L. 2006. Fetal growth restriction: pathogenic mechanisms. Clinical Obstetrics and Gynecology 49:219–227. Savvidou MD, Yu CK, Harland LC, Hingorani AD, Nicolaides KH. 2006. Maternal serum concentration of soluble fms-like tyrosine kinase 1 and vascular endothelial growth factor in women with abnormal uterine artery Doppler and in those with fetal growth restriction. American Journal of Obstetrics and Gynecology 195:1668–1673. Wallner W, Sengenberger R, Strick R, Strissel PL, Meurer B, Beckmann MW et al. 2007. Angiogenic growth factors in maternal and fetal serum in pregnancies complicated by intrauterine growth restriction. Clinical Science 112:51–57. Wathen KA, Tuutti E, Stenman UH, Alfthan H, Halmesmaki E, Finne P et al. 2006. Maternal serum-soluble vascular endothelial growth factor receptor-1 in early pregnancy ending in preeclampsia or intrauterine growth retardation. Journal of Clinical Endocrinology and Metabolism 91:180–184.
