sVEGFR-1 Concentrations Research Articles

Sunitinib treatment for patients with clear-cell metastatic renal cell carcinoma: clinical outcomes and plasma angiogenesis markers

BackgroundSunitinib is a protein tyrosine kinase-inhibitor targeting VEGFR, c-kit and PDGFR. It has been approved for the treatment of metastatic renal-cell carcinoma and gastrointestinal stromal tumors. Although it has been shown to prolong disease-free and overall survival in renal-cell carcinoma patients, only 70% of the treated population receive a clinical benefit (CB) from the treatment. Markers that could predict clinical benefit to sunitinib would be an important aid in monitoring and following their treatment. We assessed the outcome and plasma proangiogenic factors in patients with metastatic renal cell carcinoma (mRCC) treated with sunitinib in our institution.MethodsWe have treated 42 patients with metastatic clear-cell renal carcinoma with sunitinib. Plasma concentrations of VEGF-A, sVEGFR2 and PDGF were determined by ELISA.ResultsAt the time of analysis 39 patients were evaluable for response and 30 patients had obtained a clinical benefit (CB). Median progression-free survival was 268 days (8.93 months) and median overall survival was 487 days (16.23 months). Interestingly, disease stabilization or objective response resulted in comparable overall survival. Most treatment-related adverse events were of mild-to-moderate intensity with one treatment-related death. Plasma sVEGFR2 and PDGF levels had no predictive value. Fold-increase in plasma VEGF was significantly lower in patients that obtained a CB as compared to patients that progressed after two cycles of treatment. Plasma VEGF did not increase in patients with initial CB at the time of progression.ConclusionSunitinib showed substantial activity in mRCC. Disease stabilization or objective response resulted in comparable overall survival and both outcomes should be considered positive. Fold-increase in plasma VEGF predicts for CB and could be a candidate marker. Progression after initial CB is not associated with elevated plasma VEGF, implying a different mechanism of resistance.

Selected angiogenic cytokines in systemic lupus erythematosus patients

The objective of this study was to determine the serum concentration of angiogenic factors (vascular endothelial growth factor, VEGF; transforming growth factor beta, TGF-β1; hepatic growth factor, HGF; basic fibroblast growth factor, bFGF; tumor necrosis factor alpha, TNF-α; soluble vascular endothelial growth factor receptor 1, sVEGF-R1; soluble vascular endothelial growth factor receptor 2, sVEGF-R2), the relationships among them and to assess the relation of their levels with the applied therapy in 48 females with systemic lupus erythematosus (SLE; 37 long-term treated +11 newly diagnosed). The control group consisted of 24 healthy women. A statistically significant increase of sVEGF-R2 and significant decrease of sVEGF-R1 were observed in the subgroup of newly diagnosed SLE patients as compared to the control subjects. No significant differences were found between serum angiogenic factors in the long-term treated subgroup and the control, the long-term treated subgroup and the newly diagnosed SLE patients after a 3-month treatment, and the subgroup of newly diagnosed SLE patients before therapy and after a 3-month treatment. The significant decrease in the serum of sVEGF-R2 was revealed in the subgroup treated for a long-time as compared to the subgroup of newly diagnosed untreated SLE patients. The analysis of relationships between serum concentration of sVEGF-R1 and other cytokines levels revealed positive correlation with concentration of VEGF and TNF-α in the total group of patients. In the newly diagnosed untreated subgroup, a strong positive correlation between concentration of sVEGF-R1 and bFGF was observed. Furthermore, a moderate positive correlation between concentration of sVEGF-R1 and the level of VEGF was revealed in the long-term treated patients. The association between sVEGF-R2 and HGF was also noted in this subgroup. The obtained data suggest the necessity of further investigations to determine the importance of angiogenic factors in pathogenesis and therapy of SLE.

Secretion of soluble VEGF receptor 2 by microvascular endothelial cells derived by human benign prostatic hyperplasia

Vascular endothelial growth factor (VEGF) is one of the most potent mitogenic factors stimulating both prostate endothelial and prostate epithelial cells. Recently, some studies reported on the endothelial secretion of a soluble VEGF receptor 2 (sVEGFR-2) that modifies the free VEGF concentration by binding VEGF. For the first time in this study, we report on the secretion and the regulation of the secretion of sVEGFR-2 by microvascular endothelial cells derived from the tissue of human benign prostatic hyperplasia (HPEC). HPEC were isolated and cultured from fresh prostate tissue. The prostate epithelial cell line BPH-1 was cultured with the supernatant of the HPEC cell culture (fractioned by fast protein liquid chromatography) and the VEGF concentration was subsequently measured. HPEC were incubated with VEGF or tumor necrosis factor α (TNF-α). Afterwards, the concentration of sVEGFR-2 in the supernatant of unstimulated and stimulated HPEC was measured by ELISA. HPEC showed a typical endothelial morphology. Under cell culture conditions sVEGFR-2 binds VEGF: The measured VEGF concentration in the supernatant of BPH-1 cells was reduced when the fractions of HPEC conditioned medium with the highest sVEGFR-2 concentration were incubated with the BPH-1 cells. The sVEGFR-2 secretion of HPEC was stimulated by VEGF and TNF-α. For the first time we report on the secretion of sVEGFR-2 by microvascular endothelial cells of prostate origin. The secretion of sVEGFR-2 by HPEC was stimulated by VEGF and TNF-α. Our data suggest that sVEGFR-2 secreted by prostate endothelial cells could modify the effect of VEGF on prostate endothelial and prostate epithelial cells.

Soluble and Membranous Vascular Endothelial Growth Factor Receptor-2 in Pregnancies Complicated by Pre-Eclampsia

PurposeThere is a paucity of information on the serum soluble vascular endothelial growth factor receptor-2 (sVEGFR-2) concentrations, membranous VEGFR-2 expression and the mechanism involved in their modulations during the clinical onset of pre-eclampsia. This cross-sectional study was conducted to evaluate the concentration of sVEGFR-2 in serum and to investigate the expression of membranous VEGFR-2 in placentae of pre-eclampsia group.Materials and MethodsThe serum levels of sVEGFR-2 (n = 120) and the expression of membranous VEGFR-2 in placentae (n = 100) were analysed at third trimester of pregnancy by enzyme linked immunosorbent assay (ELISA) and immunohistochemistry respectively. The diagnostic parameters of sensitivity, specificity and association of soluble and membranous VEGFR-2 in these patients were evaluated.ResultsThe serum levels of sVEGFR-2 in pre-eclampsia patients were found to be significantly reduced (p = 0.01, p = 0.001) in early and late pre-eclamptic sub-groups as compared to their respective third trimester control sub-groups. Also, the receiver operating characteristic (ROC) curve analysis showed a cut-off value of 7350.4 pg/mL, higher sensitivity (76%) and specificity (76%) for sVEGFR-2 in late onset (> 34 weeks) pre-eclamptic group. Significant down-regulation of membranous VEGFR-2 immunoreactivity was observed in all the placental cells (p = 0.0001) at > 34 weeks preeclamptic group.ConclusionThe reduced serum levels of soluble VEGFR-2 and the down-regulated expression of membranous VEGFR-2 in the study group denoted abnormality in VEGF mediated placental function in all placental cells and thus VEGFR-2 may be a key factor, intimately associated with pre-eclampsia. This study shows the clinical utility of soluble and membranous VEGFR-2 in pre-eclampsia patients.

Smoking and sVEGFR-1: Circulating maternal concentrations and placental expression

Smoking reduces the expression of VEGFR-1 in non-pregnant women. In pregnant women it reduces the risk of pre-eclampsia, which in turn is associated with increased placental expression of VEGFR-1 and increased maternal circulating soluble VEGFR-1 (sVEGFR-1). We therefore hypothesized that smoking might affect VEGFR-1 expression in pregnant women. In maternal plasma sVEGFR-1 concentrations during the third trimester in both smoking (median 1088, range 834-1362ng/L, n=20) and non-smoking (728, 719-1336ng/L, n=19) women were higher than during the second trimester (smokers 374, 291-683ng/L, n=6, p>0.05; non-smokers 375, 290-667ng/L, n=22, p<0.001). No difference was observed between smokers and non-smokers. Secretion of sVEGFR-1 into the culture medium, as well as the pattern and intensity of immunostaining in first trimester placenta were similar in tissue from smoking (n=22) and non-smoking (n=20) women. Thus, contrary to our hypothesis, smoking does not affect circulating maternal sVEGFR-1 concentrations or placental secretion of sVEGFR-1 or expression of VEGFR-1 in vitro.

Role of Soluble Vascular Endothelial Growth Factor Receptor-1 in the Vitreous in Proliferative Diabetic Retinopathy

To determine the vitreous level of soluble vascular endothelial growth factor receptor-1 (sVEGFR-1) in patients with proliferative diabetic retinopathy (PDR) or idiopathic macular hole (MH). Furthermore, to investigate the relationships among sVEGFR-1, vascular endothelial growth factor (VEGF), and pigment epithelium-derived factor (PEDF). Retrospective case-control study. Thirty-eight patients who underwent vitrectomy (PDR [27 eyes in 26 patients] or MH [12 eyes in 12 patients]). In vitreous fluid samples obtained during vitreoretinal surgery, sVEGFR-1, VEGF, and PEDF levels were measured by enzyme-linked immunosorbent assay. Effects of sVEGFR-1 on VEGF-A-induced tube formation were investigated using human umbilical vein endothelial cells co-cultured with fibroblasts. Levels of sVEGFR-1 and the relationships among sVEGFR-1, VEGF, and PEDF in vitreous fluids from patients with PDR or MH. In PDR (vs MH), there were significantly higher vitreous concentrations of both sVEGFR-1 (3949.4+/-608.9 pg/mL [mean +/- standard error, n = 27] vs 1568.8+/-595.0 pg/mL [n = 12, P = 0.009]) and VEGF (1316.2+/-404.6 pg/mL [n = 27] vs 11.7+/-8.1 pg/mL [n = 12, P = 0.003]), whereas the vitreous concentration of PEDF was significantly lower (2.1+/-1.1 ng/mL [n = 27] vs 41.6+/-17.0 ng/mL [n = 12, P = 0.041]). In PDR, there was a significant positive correlation between the sVEGFR-1 and VEGF vitreous concentrations (r = 0.414, P = 0.032), but not between PEDF and VEGF (r = 0.196, P = 0.328) or between sVEGFR-1 and PEDF (r = 0.167, P = 0.406). In vitro, sVEGFR-1 (0.1-1000 ng/mL) concentration-dependently inhibited VEGF-A-induced tube formation, its effect being significant at 100 to 1000 ng/mL on the tube area, length, and path. In the vitreous fluids of patients with PDR, the sVEGFR-1 level was increased (vs that in patients with MH), and sVEGFR-1 correlated significantly with VEGF. In vitro, sVEGFR-1 reduced VEGF-induced angiogenesis. Thus, sVEGFR-1 may play a pivotal antiangiogenic role in PDR.

Is serum‐soluble vascular endothelial growth factor receptor‐1 of importance in unexplained infertility?

To analyze the role of vascular endothelial growth factor (VEGF) and its naturally occurring circulating antagonist, soluble VEGF receptor-1 (sVEGFR-1), in infertility. VEGF is a key angiogenic factor in the endometrial and ovarian cyclic processes that are crucial for fertility and sVEGFR-1 impairs its function and fertility in animals - less is known as regards human fertility. Case-control study. University Central Hospital, a tertiary referral center. Women with unexplained infertility (n=15) and fertile controls (n=10) had serial blood samples collected during their natural cycles, and the infertile women during a subsequent in vitro fertilization (IVF) cycle. Enzyme-linked immunosorbent assay was used for this study. Concentrations of VEGF and sVEGFR-1 in the natural cycles and of sVEGFR-1 during a subsequent IVF cycle. Plasma VEGF concentrations showed no cyclicity in fertile women, but were higher in the infertile group at the midluteal phase. Serum sVEGFR-1 concentrations were similar between the groups and between natural and IVF cycles. However, in infertile women, concentrations of sVEGFR-1 increased from the follicular phase to the luteal phase. In the follicular phase infertile women had a high ratio of VEGF/sVEGFR-1, which was decreased in the luteal phase. Both findings were associated with failure to achieve pregnancy in subsequent IVF cycles. One cause of unexplained infertility may be unbalanced secretion of sVEGFR-1 with concomitant changes in free VEGF during the transition from the follicular to the luteal phase. This aberration may be related to impaired implantation.

The clinical role of vascular endothelial growth factor (VEGF) system in the pathogenesis of retinopathy of prematurity

Recent experimental studies suggest that vascular endothelial growth factor (VEGF) can play an important role in the development of retinopathy of prematurity (ROP). There are interesting observations of VEGF concentration in the serum, depending on its gene polymorphism which can have an impact on abnormal vessel development in the retina. Analysis of: (1) association of VEGF gene polymorphisms and the incidence of ROP, (2) correlation between serum concentration of VEGF and soluble VEGF receptor 1 (sVEGFR-1) during the 1st month of life and the risk of ROP, and (3) correlation between VEGF gene polymorphisms and VEGF serum concentrations. A sample of 181 newborns with mean birthweight 1054 g (range: 500-1500 g) was prospectively evaluated. Molecular analysis of VEGF -460T>C and 405G>C polymorphisms were performed in the whole studied population, and concentrations of VEGF and sVEGFR-1 were measured by Elisa assay in the 2nd, 3rd and 4th weeks of life in the group of 128 children. The infants were divided into 3 groups: A) no ROP (n = 101), B) ROP not requiring treatment (n = 20), and C) ROP requiring laser or cryotherapy (n = 60). The frequency of VEGF 405G>C polymorphism was similar in all studied groups. The carriage of polymorphic allele -460 T was significantly overrepresented in ROP newborns who required treatment as compared to the no ROP group (54.2% vs 42.6%; OR: 1.63; 95% CI: 1.03-2.55). VEGF serum concentrations in the patients ascribed to different groups depending on the 405G>C or -460 T>C polymorphisms were similar. VEGF and sVEGFR-1 concentration on the 10th day of life did not differ significantly between the studied groups. Consecutive measurements showed a gradual increase in VEGF serum concentration in children without ROP, whereas in children with ROP requiring treatment the levels remained low. Based on our observations and previously published data, the association of the VEGF gene promoter polymorphisms and the risk of advanced ROP is weak. VEGF serum concentration assessment as early as on the 20th day of life appears to be a promising approach to recognize newborns at risk of the development of advanced ROP.

Axitinib Is an Active Treatment for All Histologic Subtypes of Advanced Thyroid Cancer: Results From a Phase II Study

Patients with advanced, incurable thyroid cancer not amenable to surgery or radioactive iodine ((131)I) therapy have few satisfactory therapeutic options. This multi-institutional study assessed the activity and safety of axitinib, an oral, potent, and selective inhibitor of vascular endothelial growth factor receptors (VEGFR) 1, 2, and 3 in patients with advanced thyroid cancer. Patients with thyroid cancer of any histology that was resistant or not appropriate for (131)I were enrolled onto a single-arm phase II trial to receive axitinib orally (starting dose, 5 mg twice daily). Objective response rate (ORR) by Response Evaluation Criteria in Solid Tumors was the primary end point. Secondary end points included duration of response, progression-free survival (PFS), overall survival, safety, and modulation of soluble (s) VEGFR. Sixty patients were enrolled. Partial responses were observed in 18 patients, yielding an ORR of 30% (95% CI, 18.9 to 43.2). Stable disease lasting > or = 16 weeks was reported in another 23 patients (38%). responses were noted in all histologic subtypes. Median PFS was 18.1 months (95% CI, 12.1 to not estimable). Axitinib was generally well tolerated, with the most common grade > or = 3 treatment-related adverse event being hypertension (n = 7; 12%). Eight patients (13%) discontinued treatment because of adverse events. Axitinib selectively decreased sVEGFR-2 and sVEGFR-3 plasma concentrations versus sKIT, demonstrating its targeting of VEGFR. Axitinib is a selective inhibitor of VEGFR with compelling antitumor activity in all histologic subtypes of advanced thyroid cancer.

Twin-to-twin transfusion syndrome: an antiangiogenic state?

An imbalanced chronic blood flow between the donor and recipient twin through placental vascular anastomoses is the accepted pathophysiology of twin-to-twin transfusion syndrome (TTTS). Vascular endothelial growth factor receptor-1 (VEGFR-1) mRNA is overexpressed only in the syncytiotrophoblast of the donor twin in some cases of TTTS. This study was conducted to determine maternal plasma concentrations of placental growth factor (PlGF), soluble VEGFR-1, and soluble endoglin (s-Eng) in monochorionic-diamniotic pregnancies with and without TTTS. This case-control study included monochorionic-diamniotic pregnancies between 16-26 weeks with and without TTTS. Maternal plasma concentrations of PlGF, sVEGFR-1, and s-Eng were determined with ELISA. A P value < .05 was considered statistically significant. Patients with TTTS had higher median plasma concentrations of s-Eng (14.8 ng/mL vs 7.8 ng/mL; P < .001) and sVEGFR-1 (6383.1 pg/mL vs 3220.1 pg/mL; P < .001]; and lower median plasma concentrations of PlGF (115.5 pg/mL vs 359.3 pg/mL; P = .002) than those without TTTS. We propose that an antiangiogenic state may be present in some cases of TTTS.

A longitudinal study of angiogenic (placental growth factor) and anti-angiogenic (soluble endoglin and soluble vascular endothelial growth factor receptor-1) factors in normal pregnancy and patients destined to develop preeclampsia and deliver a small for gestational age neonate

Introduction. Accumulating evidence suggests that an imbalance between pro-angiogenic (i.e., vascular endothelial growth factor (VEGF) and placental growth factor (PlGF)) and anti-angiogenic factors (i.e., soluble VEGF receptor-1 (sVEGFR-1, also referred to as sFlt1)) is involved in the pathophysiology of preeclampsia (PE). Endoglin is a protein that regulates the pro-angiogenic effects of transforming growth factor β, and its soluble form has recently been implicated in the pathophysiology of PE. The objective of this study was to determine if changes in maternal plasma concentration of these angiogenic and anti-angiogenic factors differ prior to development of disease among patients with normal pregnancies and those destined to develop PE (preterm and term) or to deliver a small for gestational age (SGA) neonate.Methods. This longitudinal nested case–control study included 144 singleton pregnancies in the following groups: (1) patients with uncomplicated pregnancies who delivered appropriate for gestational age (AGA) neonates (n = 46); (2) patients who delivered an SGA neonate but did not develop PE (n = 56); and (3) patients who developed PE (n = 42). Longitudinal samples were collected at each prenatal visit, scheduled at 4-week intervals from the first or early second trimester until delivery. Plasma concentrations of soluble endoglin (s-Eng), sVEGFR-1, and PlGF were determined by specific and sensitive ELISA.Results. (1) Patients destined to deliver an SGA neonate had higher plasma concentrations of s-Eng throughout gestation than those with normal pregnancies; (2) patients destined to develop preterm PE and term PE had significantly higher concentrations of s-Eng than those with normal pregnancies at 23 and 30 weeks, respectively (for preterm PE: p < 0.036 and for term PE: p = 0.002); (3) patients destined to develop PE (term or preterm) and those who delivered an SGA neonate had lower plasma concentrations of PlGF than those with a normal pregnancy throughout gestation, and the maternal plasma concentration of this analyte became detectable later among patients with pregnancy complications, compared to normal pregnant women; (4) there were no significant differences in the plasma concentrations of sVEGFR-1 between patients destined to deliver an SGA neonate and those with normal pregnancies; (5) patients destined to develop preterm and term PE had a significantly higher plasma concentration of sVEGFR-1 at 26 and 29 weeks of gestation than controls (p = 0.009 and p = 0.0199, respectively); and (6) there was no significant difference in the increment of sVEGFR-1 between control patients and those who delivered an SGA neonate (p = 0.147 at 25 weeks and p = 0.8285 at 40 weeks).Conclusions. (1) Changes in the maternal plasma concentration of s-Eng, sVEGFR-1, and PlGF precede the clinical presentation of PE, but only changes in s-Eng and PlGF precede the delivery of an SGA neonate; and (2) differences in the profile of angiogenic and anti-angiogenic response to intrauterine insults may determine whether a patient will deliver an SGA neonate, develop PE, or both.

The change in concentrations of angiogenic and anti-angiogenic factors in maternal plasma between the first and second trimesters in risk assessment for the subsequent development of preeclampsia and small-for-gestational age

Introduction. An imbalance between angiogenic and anti-angiogenic factors has been proposed as central to the pathophysiology of preeclampsia (PE). Indeed, patients with PE and those delivering small-for-gestational age (SGA) neonates have higher plasma concentrations of soluble vascular endothelial growth factor receptor-1 (sVEGFR-1) and the soluble form of endoglin (s-Eng), as well as lower plasma concentrations of vascular endothelial growth factor (VEGF) and placental growth factor (PlGF) than do patients with normal pregnancies. Of note, this imbalance has been observed before the clinical presentation of PE or the delivery of an SGA neonate. The objective of this study was to determine if changes in the profile of angiogenic and anti-angiogenic factors in maternal plasma between the first and second trimesters are associated with a high risk for the subsequent development of PE and/or delivery of an SGA neonate.Methods. This longitudinal case–control study included 402 singleton pregnancies in the following groups: (1) normal pregnancies with appropriate for gestational age (AGA) neonates (n = 201); (2) patients who delivered an SGA neonate (n = 145); and (3) patients who developed PE (n = 56). Maternal plasma samples were obtained at the time of each prenatal visit, scheduled at 4-week intervals from the first or early second trimester until delivery. In this study, we included two samples per patient: (1) first sample obtained between 6 and 15 weeks of gestation (‘first trimester’ sample), and (2) second sample obtained between 20 and 25 weeks of gestation (‘second trimester’ sample). Plasma concentrations of s-Eng, sVEGFR-1, and PlGF were determined by specific and sensitive immunoassays. Changes in the maternal plasma concentrations of these angiogenesis-related factors were compared among normal patients and those destined to develop PE or deliver an SGA neonate while adjusting for maternal age, nulliparity, and body mass index. General linear models and polytomous logistic regression models were used to relate the analyte concentrations, ratios, and product to the subsequent development of PE and SGA.Results. (1) An increase in the maternal plasma concentration of s-Eng between the first and second trimesters conferred risk for the development of preterm PE and SGA (OR 14.9, 95% CI 4.9–45.0 and OR 2.9, 95% CI 1.5–5.6, respectively). (2) An increase in the maternal plasma concentration of sVEGFR-1 between the first and second trimester conferred risk for the development of preterm PE (OR 3.9, 95% CI 1.2–12.6). (3) A subnormal increase in maternal plasma PlGF concentration between the first and the second trimester was a risk factor for the subsequent development of preterm and term PE (OR 4.3, 95% CI 1.2–15.5 and OR 2.7, 95% CI 1.2–5.9, respectively). (4) In addition, the combination of the three analytes into a pro-angiogenic versus anti-angiogenic ratio (PlGF/(s-Eng × VEGFR-1)) conferred risk for the subsequent development of preterm PE (OR 3.7, 95% CI 1.1–12.1). (5) Importantly, patients with a high change in the s-Eng × sVEGFR-1 product had an OR of 10.4 (95% CI 3.2–33.8) for the development of preterm PE and 1.6 (95% CI 1.0–2.6) for the development of SGA.Conclusions. Changes in the maternal plasma concentrations of s-Eng, sVEGFR-1, PlGF or their ratios between the first and second trimesters of pregnancy confer an increased risk to deliver an SGA neonate and/or develop PE.

The maternal plasma soluble vascular endothelial growth factor receptor-1 concentration is elevated in SGA and the magnitude of the increase relates to Doppler abnormalities in the maternal and fetal circulation

Objectives. The soluble form of vascular endothelial growth factor receptor-1 (sVEGFR-1), an antagonist to vascular endothelial growth factor and placental growth factor, has been implicated in the pathophysiology of preeclampsia. Preeclampsia and pregnancy complicated with small for gestational age (SGA) fetuses share some pathophysiologic derangements, such as failure of physiologic transformation of the spiral arteries, endothelial cell dysfunction, and leukocyte activation. The objectives of this study were to: (1) determine whether plasma concentrations of sVEGFR-1 in mothers with SGA fetuses without preeclampsia at the time of diagnosis are different from those in patients with preeclampsia or normal pregnant women, and (2) examine the relationship between plasma concentrations of sVEGFR-1 and Doppler velocimetry in uterine and umbilical arteries in patients with preeclampsia and those with SGA.Study design. A cross-sectional study was conducted to determine the concentrations of the soluble form of VEGFR-1 in plasma obtained from normal pregnant women (n = 135), women with SGA fetuses (n = 53), and patients with preeclampsia (n = 112). Patients with SGA fetuses and those with preeclampsia were sub-classified according to the results of uterine and umbilical artery Doppler velocimetry examinations. Plasma concentrations of sVEGFR-1 were determined by an ELISA. Since these concentrations change with gestational age, differences among various subgroups were statistically estimated with the delta value, defined as the difference between the observed and expected plasma sVEGFR-1 concentration. The expected values were derived from regression analysis of plasma sVEGFR-1 concentrations in normal pregnancy. Regression analysis and univariate and multivariate analysis were employed.Results. (1) Mothers with SGA fetuses had a mean plasma concentration of sVEGFR-1 higher than normal pregnant women (p < 0.001), but lower than patients with preeclampsia (p < 0.001). (2) Among patients with SGA fetuses, only those with abnormal uterine artery Doppler velocimetry had a mean plasma sVEGFR-1 concentration significantly higher than normal pregnant women (p < 0.001). (3) Among mothers with SGA fetuses in whom Doppler velocimetry was performed (n = 41), those with abnormalities in both the uterine and umbilical artery velocimetry had the highest mean delta of sVEGFR-1 plasma concentration (mean ± standard deviation (SD): 0.69 ± 0.29). Conversely, patients who had normal Doppler velocimetry in both uterine and umbilical arteries had the lowest mean delta (mean ± SD: 0.09 ± 0.29) of sVEGFR-1 plasma concentrations (ANOVA; p < 0.001). (4) Among patients with preeclampsia in whom Doppler velocimetry was performed (n = 69), those with abnormalities in both the uterine and umbilical artery velocimetry had the highest mean delta sVEGFR-1 plasma concentration (mean ± SD: 1.01 ± 0.22) among all groups classified (ANOVA; p < 0.001). (5) Among patients with SGA and those with preeclampsia, there was a relationship (Chi-square for trend p < 0.001 for both) between the severity of Doppler velocimetry abnormalities and the proportion of patients who had high delta sVEGFR-1 plasma concentrations (defined as a concentration two standard deviations (2SD) above the mean delta of normal pregnant women). (6) Multiple regression analysis suggested that the diagnostic category (e.g., SGA or preeclampsia), Doppler abnormalities, and gestational age at blood sampling were associated with an increase in plasma sVEGFR-1 concentrations (p < 0.001).Conclusions. These observations provide support for the participation of the soluble receptor of vascular endothelial growth factor in the pathophysiology of SGA with abnormal uterine artery Doppler velocimetry and preeclampsia. An excess of sVEGFR-1 is released into the maternal circulation of patients with preeclampsia and those with SGA fetuses, as abnormalities of impedance to blood flow involve uterine and umbilical circulation.

Low maternal concentrations of soluble vascular endothelial growth factor receptor-2 in preeclampsia and small for gestational age

Objectives. Preeclampsia is considered an anti-angiogenic state. A role for the anti-angiogenic factors soluble vascular endothelial growth factor receptor-1 (sVEGFR-1) and soluble endoglin in preeclampsia has been proposed. Soluble vascular endothelial growth factor receptor-2 (sVEGFR-2) has been detected in human plasma, and the recombinant form of this protein has anti-angiogenic activity. There is a paucity of information about maternal plasma sVEGFR-2 concentrations in patients with preeclampsia and those without preeclampsia with small for gestational age (SGA) fetuses. This study was conducted to determine whether: (1) plasma sVEGFR-2 concentration changes throughout pregnancy; and (2) preeclampsia and SGA are associated with abnormalities in the maternal plasma concentration of sVEGFR-2.Study design. This cross-sectional study included non-pregnant women (n = 40), women with normal pregnancies (n = 135), women with an SGA fetus (n = 53), and women with preeclampsia (n = 112). SGA was defined as an ultrasound-estimated fetal weight below the 10th percentile for gestational age that was confirmed by neonatal birth weight. Plasma concentrations of sVEGFR-2 were determined by ELISA.Results. (1) There was no significant difference in the mean plasma concentration of sVEGFR-2 between non-pregnant women and those with normal pregnancies (p = 0.8); (2) patients with preeclampsia and those without preeclampsia with SGA fetuses had a lower mean plasma concentration of sVEGFR-2 than that of women with normal pregnancies (p < 0.001 for both); and (3) there was no significant difference in the mean plasma concentration of sVEGFR-2 between patients with preeclampsia and those without preeclampsia with SGA (p = 0.9).Conclusions. Preeclampsia and SGA are associated with low plasma concentrations of sVEGFR-2. One interpretation of the findings is that plasma sVEGFR-2 concentration could reflect endothelial cell function.

Serum Levels of VEGF-C, VEGF-D, and sVEGF-R2 in Patients With Lung Cancer During Chemotherapy

The aim of this study was to assess serum levels of vascular endothelial growth factor C and D (VEGF-C, VEGF-D) and soluble VEGF receptor 2 (sVEGFR-2) in patients with lung cancer during chemotherapy. The study included 80 patients (64 men and 16 women; mean age 61.1) diagnosed histologically with lung cancer. Forty-four (55%) had non-small cell lung cancer (NSCLC) and 36 (45%) had small cell lung cancer (SCLC). Squamous cell carcinoma was established in 56% (25 patients) of all patients with NSCLC, adenocarcinoma in 20% (9 patients), and non-small cell lung cancer in 23% (10 patients). The control group consisted of 20 healthy volunteers. Peripheral blood samples were taken before and after four cycles of chemotherapy. VEGF-C, VEGF-D, and sVEGFR-2 levels were assessed by ELISA method. Serum levels of VEGF-C and VEGF-D were significantly higher in both NSCLC and SCLC groups in comparison with controls. VEGF-C concentration decreased after chemotherapy, whereas VEGF-D concentration was at the same level. No correlation was found between VEGF-C and VEGF-D concentrations and the effect of treatment. Patients with lung cancer and progression after chemotherapy (PD) had the higher concentration of sVEGFR-2 than patients with partial remission (PR). The levels of sVEGFR-2 were lower before and after treatment than in controls. No relation was found between VEGF-C, VEGF-D, and sVEGFR-2 concentrations and the histological type and staging of lung cancer. Summing up, serum concentrations of VEGF-C and VEGF-D were higher in patients with lung cancer both before and after chemotherapy than in healthy controls, whereas sVEGFR-2 concentration was lower than in healthy controls. An increase in concentration of sVEGFR-2 during chemotherapy may suggest progression of the disease. However, it requires further examination.

Prognostic relevance of pretreatment soluble vascular endothelial growth factors (A,C,D) and their receptors (R1, R2, and R3) in advanced melanoma patients

8540 Background and aims: Circulating vascular endothelial growth factors (VEGFs) and their receptors (VEGFRs) were described as prognostic factors in several cancers. The aim of this study is to evaluate the prognostic values of these parameters in metastatic malignant melanoma diseases. Methods and Patients: Using enzyme-linked immunosorbent assays, VEGFs (A, C, D) and their receptors (1, 2, and 3) were measured in sera of 75 patients with metastatic malignant melanoma in comparison to 30 healthy controls. Disease free survival (DFS) and overall survival (OS) were calculated from the beginning of the treatment until either the progression or the death and analyzed using the Kaplan-Meier method. Results: Pretreatment median sVEGF-A, sVEGF-C as well as VEGFR-3 levels were significantly higher in MMM patients as compared to healthy ones p=0.0017, p=0.005, p&lt;0.00001 respectively). None of the studied markers correlated with gender, age or LDH levels. An inverse correlation between soluble VEGFR-2 and VEGF-D levels was observed (r=−0.33 p=0.040). High soluble VEGF-C and VEGFR-3 were correlated to high tumor burden (p=0.02, p=0.045). However, a relationship with lymph node metastasis was observed with sVEGF-A but not with sVEGFR-3. As shown by univariate analysis, only elevated levels of sVEGF-R1 concentration were found to exert a significantly unfavorable impact on both disease-free (χ2=6.64, p= 0.014) and overall survival (χ2=8.03, p= 0.0046). Conclusions: Our results suggest that, in metastatic malignant melanoma patients, soluble VEGF-A and VEGF-R3 pretreatment levels may prospectively identify high-risk patients with a worse prognosis; serum VEGFR-1 level may be a predictive factor of time to progression and overall survival. A multivariate analysis (Cox test) is ongoing in order to confirm if this parameter is an independent prognostic factor. No significant financial relationships to disclose.

Emerging Roles of Antiangiogenic and Angiogenic Proteins in Pathogenesis and Prediction of Preeclampsia

Hypertensive disorders are a major cause of maternal and fetal death, especially in developing nations, with the pregnancy-specific disease preeclampsia-eclampsia responsible for most of this mortality. Preeclampsia, recognized by ancient Greeks, was only sporadically investigated until late last century, current literature still labeling this disorder a “disease of theories.” Thus, not surprisingly, we have started the new millennium unable to predict or prevent preeclampsia, and management strategies remain but supportive, with pregnancy termination still the only definitive “therapy.” This may be about to change, as focused research, mainly in the past decade, has resulted in dramatic progress regarding pathogenesis of disease manifestations and risk assessment, while investigators have begun designing and testing definitive therapy.1 There are still a myriad of uncertainties and unanswered questions to address, but here we summarize the extent of 1 new and exciting chapter in preeclampsia research: the roles of angiogenic and antiangiogenic factors, to which an article in this issue by Rana and colleagues,2 contributes. A landmark report published in 2003 set the stage for all that followed.3 Dr Karumanchi’s laboratory, previously involved in renal cancer research, changed its focus to the kidney in preeclampsia. Using microarray chip technology, they probed gene expression profiles in placentas of women with preeclampsia and those with uncomplicated pregnancies. Of course many differences were noted, but one that caught the investigators’ attention was upregulation of the mRNA for the antiangiogenic protein soluble fms-like tyrosine kinase 1 (abbreviated as sFlt-1 or sVEGFR-1) in placentas from women with preeclampsia. Aware that de novo hypertension and proteinuria were 2 disturbing side effects of certain antiangiogenic compounds tested in cancer patients, these …

Identification of patients at risk for early onset and/or severe preeclampsia with the use of uterine artery Doppler velocimetry and placental growth factor

Preeclampsia has been proposed to be an antiangiogenic state that may be detected by the determination of the concentrations of the soluble vascular endothelial growth factor receptor-1 (sVEGFR-1) and placental growth factor (PlGF) in maternal blood even before the clinical development of the disease. The purpose of this study was to determine the role of the combined use of uterine artery Doppler velocimetry (UADV) and maternal plasma PlGF and sVEGFR-1 concentrations in the second trimester for the identification of patients at risk for severe and/or early onset preeclampsia. A prospective cohort study was designed to examine the relationship between abnormal UADV and plasma concentrations of PlGF and sVEGFR-1 in 3348 pregnant women. Plasma samples were obtained between 22 and 26 weeks of gestation at the time of ultrasound examination. Abnormal UADV was defined as the presence of bilateral uterine artery notches and/or a mean pulsatility index above the 95th percentile for the gestational age. Maternal plasma PlGF and sVEGFR-1 concentrations were determined with the use of sensitive and specific immunoassays. The primary outcome was the development of early onset preeclampsia (< or = 34 weeks of gestation) and/or severe preeclampsia. Secondary outcomes included preeclampsia, the delivery of a small for gestational age (SGA) neonate without preeclampsia, spontaneous preterm birth at < or = 32 and < or = 35 weeks of gestation, and a composite of severe neonatal morbidity. Contingency tables, chi-square test, receiver operating characteristic curve, and multivariate logistic regression were used for statistical analyses. A probability value of < .05 was considered significant. (1) The prevalence of preeclampsia, severe preeclampsia, and early onset preeclampsia were 3.4% (113/3296), 1.0% (33/3296), and 0.8% (25/3208), respectively. UADV was performed in 95.4% (3146/3296) and maternal plasma PlGF concentrations were determined in 93.5% (3081/3296) of the study population. (2) Abnormal UADV and a maternal plasma PlGF of < 280 pg/mL were independent risk factors for the occurrence of preeclampsia, severe preeclampsia, early onset preeclampsia, and SGA without preeclampsia. (3) Among patients with abnormal UADV, maternal plasma PlGF concentration contributed significantly in the identification of patients destined to develop early onset preeclampsia (area under the curve, 0.80; P < .001) and severe preeclampsia (area under the curve, 0.77; P < .001). (4) In contrast, maternal plasma sVEGFR-1 concentration was of limited use in the prediction of early onset and/or severe preeclampsia. (5) The combination of abnormal UADV and maternal plasma PlGF of < 280 pg/mL was associated with an odds ratio (OR) of 43.8 (95% CI, 18.48-103.89) for the development of early onset preeclampsia, an OR of 37.4 (95% CI, 17.64-79.07) for the development of severe preeclampsia, an OR of 8.6 (95% CI, 5.35-13.74) for the development of preeclampsia, and an OR of 2.7 (95% CI, 1.73-4.26) for the delivery of a SGA neonate in the absence of preeclampsia. The combination of abnormal UADV and maternal plasma PlGF concentration of < 280 pg/mL in the second trimester is associated with a high risk for preeclampsia and early onset and/or severe preeclampsia in a low-risk population. Among those with abnormal UADV, a maternal plasma concentration of PlGF of < 280 pg/mL identifies most patients who will experience early onset and/or severe preeclampsia.

Unexplained fetal death: Another anti-angiogenic state

Background. Pregnancy creates a unique situation in which both vasculogenesis and extensive angiogenesis are required for successful fetal and placental development. Recently, the soluble form of vascular endothelial growth factor (VEGF) receptor-1 (sVEGFR-1), an antagonist to VEGF and placental growth factor (PlGF) (two important angiogenic factors), has been implicated in the pathophysiology of preeclampsia and small for gestational age (SGA) without preeclampsia. There is, however, a paucity of information concerning plasma sVEGFR-1 concentrations in other obstetrical disorders. The purpose of this study was to determine plasma sVEGFR-1 concentrations in normal pregnancy, term gestation in labor, and in patients with pregnancy complications including spontaneous preterm labor, preterm premature rupture of the membranes (PROM), fetal death, and acute pyelonephritis.Methods. A cross-sectional study was conducted to determine the concentrations of sVEGFR-1 in plasma obtained from 499 women in the following groups: (1) non-pregnant women (n = 40); (2) pregnant women (n = 135); (3) normal pregnant women at term in labor (n = 60); (4) fetal death (n = 60); (5) spontaneous preterm labor with intact membranes (n = 102); (6) preterm PROM (n = 64); and (7) pregnancy with acute pyelonephritis (n = 38). Since plasma sVEGFR-1 concentration changes with gestational age, the difference between the actual and the expected plasma sVEGFR-1 concentration (derived from regression equation of normal pregnancy) for each patient (delta value) was calculated and used to examine the differences of plasma sVEGFR-1 concentrations among various groups. Plasma concentrations of sVEGFR-1 were determined by enzyme-linked immunoassay. Regression analysis and non-parametric statistics were used for analysis.Results. (1) Normal pregnant women before term had a median plasma sVEGFR-1 concentration significantly higher than non-pregnant women (p < 0.001); (2) plasma sVEGFR-1 concentration increased with advancing gestational age in normal pregnancy (r = 0.5; p < 0.001); (3) there was no significant difference in the median delta plasma concentration of sVEGFR-1 between normal pregnant women at term with and without labor (p = 0.09); (4) patients with fetal death had a median delta plasma concentration of sVEGFR-1 significantly higher than normal pregnant women (p = 0.001). Among patients with fetal death, those with unexplained causes (p = 0.04) and those with preeclampsia (p < 0.001) had a significantly higher delta plasma sVEGFR-1 concentration than normal pregnant women; and (5) there was no significant difference in the median delta plasma sVEGFR-1 concentration between normal pregnancy and preterm labor with intact membranes, preterm PROM (regardless of the presence or absence of microbial invasion of the amniotic cavity), or acute pyelonephritis (all p > 0.05).Conclusions. Plasma sVEGFR-1 concentration is increased in a subset of patients with fetal death, but does not change in term and preterm parturition, rupture of fetal membranes, or acute pyelonephritis.

The timed‐pregnant baboon animal model can be used for determining the role of soluble vascular endothelial growth factor receptors 1 and 2 during development

During pregnancy, mechanisms that allow for regulation of continuous fetal and placental vasculogenesis with prevention of maternal neo-vascularization remain elusive. The vascular endothelial growth factor (VEGF) biological system has a key role during vasculogenesis. The aims of this study were to validate a bioassay for soluble vascular endothelial growth factor receptors 1 and 2 (sVEGFR-1 and sVEGFR-2) in baboon plasma and to determine the maternal and fetal plasma concentration of these receptors at the end of the baboon pregnancy. Maternal peripheral blood samples were obtained from eight baboons (Papio anubis) prior to elective cesarean section and from the umbilical cord after the fetuses were delivered. Spike and recovery experiments at various concentrations in pooled baboon maternal plasma were used to validate a human quantitative sandwich immunoassay for sVEGFR-1 and -2. Concentrations of sVEGFR-1 and -2 were then determined in maternal and fetal plasma samples. No significant correlations were observed between sVEGFR-1 or -2 concentrations in maternal and fetal circulations. The concentration of sVEGFR-1 was at least 30 times greater and that of sVEGFR-2 approximately two times greater, in maternal than in cord plasma (both P < 0.01). These findings suggest that baboons can be used to study the regulation of vasculogenesis during pregnancy.