VEGF, bFGF and their receptors at the fetal-maternal interface of the rhesus monkey

Investigation of HoxB3 and Growth Factors Expression in Placentas of Various Gestational Ages

An evaluation of transforming growth factor beta (TGFβ), hepatocyte growth factor (HGF), basic fibroblast growth factor (FGF-2), fibroblast growth factors receptor 1 (FGFR1) and Hox-positive cells in the human placenta, and their correlation with gestational time at delivery and pregnancy outcomes, may provide not only a better understanding of the role of Hox genes and growth factors in human development, but also may be of clinical importance in reproductive medicine. This study analyzed the immunohistochemical identification of TGFβ, HGF, FGF-2, FGFR1 and HoxB3 in placentas of various gestational ages. We found few (+) TGFβ, moderate (++) FGF-2 and numerous (+++) HGF and FGFR1 positive structures. Occasional (0/+) to numerous (+++) HoxB3-positive structures were detected in different types of placental cells specifically, cytotrophoblasts, syncytiotrophoblast, extravillous trophoblasts, and Höfbauer cells. Correlating the appearance of HoxB3 staining in placentas with neonatal parameters, we found a statistically significant negative correlation with ponderal index (r = −0.323, p = 0.018) and positive correlation with neonate body length (r = 0.541, p = 0.046). The number of HoxB3-positive cells did not correlate with growth factors and gestational age, but with neonatal anthropometrical parameters, indicating the role of HoxB3 not only in placental development, but also in the longitudinal growth of the fetus. TGFβ and FGF-2 did not play a significant role in the development of the placenta beyond 22nd week of pregnancy, while HGF and FGFR1 immunoreactive cells increased with advancing gestation, indicating increasingly evolving maturation (growth, proliferation) of the placenta, especially in the third trimester.

Temporal expression and localization of vascular endothelial growth factor family members in the bovine uterus during peri-implantation period

The aim of this study was to determine endometrial mRNA expression patterns and uterine protein localizations of vascular endothelial growth factor (VEGF) ligands (VEGFA, VEGFB, VEGFC, and VEGFD) and their receptors (VEGFR1, soluble VEGFR1 (sVEGFR1), VEGFR2, and VEGFR3) during the peri-implantation period in cows. The number of blood and lymphatic vessels in the bovine uterus was also investigated. Bovine uterine tissues were collected from pregnant animals on days 15, 18, and 27 after artificial insemination and from non-pregnant animals on days 15 and 18 of the estrous cycle (day 0 = day of estrus). The mRNA expression level of VEGFA, VEGFR1, sVEGFR1, and VEGFR3 were higher on day 18 than on day 15 in the non-pregnant group. On day 18, the levels of mRNA expression of these genes were higher in the non-pregnant group than in the pregnant group. VEGFB mRNA expression levels was higher on day 15 than on days 18 and 27 of gestation and was higher in the pregnant group than in the non-pregnant group on day 15. Using immunohistochemistry, VEGF ligands and their receptors were found in luminal epithelium, glandular epithelium, stroma, and blood vessels of the endometrium. In addition, VEGFA, VEGFD, and VEGFR3 were also detected in the uterine myometrium. In the pregnant group, the number of blood vessels in the endometrium increased from day 15 to 18 and was greater than that of the non-pregnant group on day 18. Our results demonstrate that the VEGF family is expressed and regulated in the bovine uterus during the peri-implantation period, which may be associated with uterine functions, including vascular remodeling in maternal recognition of pregnancy and implantation.

Association between vascular endothelial growth factor promoter polymorphisms and the risk of recurrent implantation failure

The objective of the present study was to investigate the association between recurrent implantation failure (RIF) and vascular endothelial growth factor (VEGF) gene polymorphisms that are associated with various female infertility disorders. A total of 116 women diagnosed with RIF and 218 control subjects were genotyped for the VEGF -2578C>A, -1154G>A, -634C>G and 936C>T polymorphisms using a polymerase chain reaction-restriction fragment length polymorphism assay. The VEGF -2578AA genotype was associated with an increased prevalence (≥4) of RIF [adjusted odds ratio (AOR)=2.77; 95% confidence interval (CI)=1.10-7.02; P=0.031], whereas the VEGF -634CG+GG genotype was associated with an increased incidence of total RIF (AOR=2.03; 95% CI=1.02-4.05; P=0.044) and ≥4 RIF (AOR=3.16; 95% CI=1.19-8.37; P=0.021). The results of the haplotype analysis indicated that -2578A/-1154A/-634G/936C (AOR=1.76; 95% CI=1.03-3.00; P=0.040 for total RIF and AOR=2.11; 95% CI=1.12-3.97; P=0.021 for ≥4 RIF) was associated with the occurrence of RIF. In addition, it was revealed that there was a significant difference in serum prolactin level associated with the VEGF -634C>G polymorphism (P=0.013). Therefore the findings of the present study indicate that the VEGF -2578AA genotype, -634G allele and -2578A/-1154A/-634G/936C haplotype may be genetic markers for susceptibility to RIF. However, further studies on VEGF promoter polymorphisms that include an independent randomized-controlled population are required to confirm these results.

The interplay of human chorionic gonadotropin (hCG) with basic fibroblast growth factor and adipokines on angiogenesis in vitro

INTRODUCTION

Human chorionic gonadotropin (hCG) is suggested to regulate placental angiogenesis, however, its role is incompletely understood. hCG may directly stimulate angiogenesis or influence the effect of other angiogenic factors. We examined the effect of hCG and the interplay of hCG with basic fibroblast growth factor (bFGF) and with various adipokines on proliferation of vascular endothelial cells in vitro.

METHODS

Human umbilical vein endothelial cells (HUVEC) were incubated for 2 days with combinations of hCG, bFGF, leptin, resistin, adiponectin, IL6 and TNFα. Incorporation of radiolabelled thymidine was used to assess cell proliferation. Immunofluorescence and flow cytometry were used to examine activation of p44/42 mitogen-activated kinase (MAPK).

RESULTS

hCG induced proliferation of HUVEC alone and in combination with bFGF. Cells exposed to both hCG and bFGF displayed increased activation of p44/42 MAPK as compared to hCG or bFGF alone. Increased HUVEC proliferation was observed in the presence of increasing concentrations of leptin, resistin, adiponectin, and IL6, whereas HUVEC proliferation decreased in the presence of TNFα. hCG in combination with leptin, resistin, adiponectin or IL6 stimulated HUVEC proliferation beyond the effect of hCG alone.

DISCUSSION

An interplay of hCG with adipose tissue-derived factors with angiogenic properties is plausible. Thus, maternal obesity may affect placental angiogenesis in pregnancy.

CONCLUSIONS

hCG may directly stimulate angiogenesis. Also, hCG may indirectly stimulate angiogenesis through interplay with bFGF and adipokines.

Capillary electrophoresis of bone marrow stromal cells with uptake of heparin-functionalized poly(lactide-co-glycolide) nanoparticles during differentiation towards neurons

This study analyzes the varying electrophoretic mobility and zeta potential of bone marrow stromal cells (BMSCs) during their differentiation towards neurons. Electrophoresis of primary BMSCs and neuron growth factor (NGF)-induced neuron-like cells with the uptake of heparin-functionalized poly(lactide-co-glycolide) (PLGA) nanoparticles (NPs) are also investigated. Immunofluorescent images revealed that a high concentration of NGF accelerated the differentiation of BMSCs into neurons. When the concentration of NGF increased, the absolute values of electrophoretic mobility and zeta potential of the differentiating BMSCs increased. In addition, a longer inductive period yielded higher charge of the differentiating BMSCs and a smaller uptake amount of heparin-functionalized PLGA NPs. However, an increase in the loading efficiency of heparin on PLGA NPs enhanced the uptake and reduced the electrical characteristics of the primary and differentiating BMSCs. Hence, a general rule is drawn that an increase in the uptake of heparin-functionalized PLGA NPs decreased the electrophoretic mobility and zeta potential of BMSCs during differentiation towards neurons.

Placental gene transfer: transgene screening in mice for trophic effects on the placenta

OBJECTIVE

We hypothesized that gene transfer of select growth factors to the placenta may enhance placental and fetal growth. Thus, we examined the effect of 8 growth factor transgenes on murine placenta.

STUDY DESIGN

Adenoviral-mediated site-specific intraplacental gene transfer of 8 different growth factor transgenes at embryonic day (e) 14 was performed. Transgenes included angiopoietin-1, angiopoietin-2 (Ang-2), basic fibroblast growth factor, hepatocyte growth factor, insulin-like growth factor-1 (IGF-1), placenta growth hormone, platelet-derived growth factor-B (PDGF-B), and vascular endothelial growth factor(121). Fetuses and placentas were harvested at e17 and assessed for survival, gene transfer efficiency, placenta area, and fetal and placental weights.

RESULTS

Efficient gene transfer to the placenta was detected with minimal dissemination to the fetus. Overexpression of IGF-1, PDGF-B, and Ang-2 resulted in an increase in placenta cross-sectional area. Only Ang-2 gene transfer resulted in increased fetal weight, and only Ang-2 and basic fibroblast growth factor resulted in a change in placental weight.

CONCLUSION

Site-specific placental gene transfer results in efficient gene transfer with minimal dissemination to the fetus. Adenoviral-mediated IGF-1, adenoviral-mediated PDGF-B, and adenoviral-mediated Ang-2 significantly increase placenta growth.

Placental expression of insulin-like growth factor-I, fibroblast growth factor-basic and neural cell adhesion molecule in pregnancies with small for gestational age fetuses

OBJECTIVE

To investigate placental expression of insulin-like growth factor-I (IGF-I), fibroblast growth factor-basic (FGF-b) and neural cell adhesion molecule (N-CAM) regarding the pathogenesis of pregnancies with small for gestational age (SGA) fetuses.

STUDY DESIGN

An immunohistochemical analysis using anti-IGF-I, anti-FGF-b and anti-N-CAM antibodies was carried out on 4% paraformaldehyde-fixed placental tissues of third trimester pregnancies complicated with SGA fetuses (n=12) and subjects exhibiting appropriately grown fetuses (n=10). Immunostaining patterns of chorionic villi and amniochorionic membranes were assessed.

RESULT

IGF-I, FGF-b and N-CAM immunostainings in chorionic villi demonstrated significantly increased immunoreactivities in cytotrophoblasts of SGA cases, whereas increased IGF-I immunostaining in syncitiotrophoblasts and increased N-CAM immunostaining in capillary endothelium were noted in the same group. IGF-I, FGF-b and N-CAM immunostainings in amniochorionic membranes revealed significantly decreased IGF-I immunoreactivities in extravillous trophoblasts and increased IGF-I immunoreactivities in decidual cells of SGA cases, while significantly decreased N-CAM immunoreactivities in both decidual cells and extravillous trophoblasts were noted. FGF-b immunostaining revealed no significant differences in both extravillous trophoblasts and decidual cells of SGA cases.

CONCLUSION

Increased placental expression of IGF-I, FGF-b and N-CAM may act in an autocrine and/or paracrine manner to restore the impaired trophoblastic proliferation, migration and metabolism at all gestational stages by means of a positive feedback mechanism.

Angiogenesis in implantation

PROBLEM

Implantation failure and early pregnancy loss are common following natural conceptions and they are particularly important clinical hurdles to overcome following assisted reproduction attempts. The importance of adequate vascular development and maintenance during implantation has recently become a major focus of investigation.

MATERIALS AND METHODS

Review of current published literature was undertaken to summerize the cells and cell products that regulate tissue vascularity during implantation.

RESULTS

Vascular development at the maternal fetal interface can be regulated by a number of different cell types; two principal candidates are trophoblast and natural killer cells. A wide range of soluble factors, some with well established angiogenic functions as well as other more novel factors, can contribute to vascular development and maintenance at the maternal-fetal interface.

CONCLUSIONS

Robust vascular development occurs during implantation and early placentation of normal pregnancies. Studies to define the extent and mechanisms by which defects in vascularity contribute to human implantation failure and early miscarriage need to be undertaken.

Fator de crescimento fibroblástico básico e seus receptores em relação à atividade proliferativa na placenta bubalina em diferentes fases da gestação

Estudou-se a distribuição espaço-temporal do fator de crescimento fibroblástico básico (bFGF), do receptor 1 do fator de crescimento fibroblástico (FGFR1) e do receptor 2 do fator de crescimento fibroblástico (FGFR2) na placenta bubalina, correlacionando-a à proliferação celular. Para a detecção do bFGF, FGFR1, FGFR2 e antígeno Ki-67, colheram-se 12 placentas de búfalas nos terços inicial, médio e final da gestação, em abatedouros, e realizaram-se testes de imunoistoquímica. Detectou-se e avaliou-se a expressão do bFGF, do FGFR1, do FGFR2 e do antígeno Ki-67 ao longo da gestação. No compartimento fetal da placenta, observaram-se correlações positivas entre a expressão do bFGF e Ki-67, entre FGFR1 e Ki-67 e entre FGFR2 com Ki-67 (r=0,313, 0,358 e 0,384, respectivamente). No epitélio e estroma maternos observaram-se altas correlações entre FGFR1 e Ki-67 (r=0,739 e r=0,511, respectivamente). Os resultados sugerem envolvimento do bFGF, FGFR1 e FGFR2 na proliferação do trofoblasto enquanto no compartimento materno da placenta bubalina apenas o FGFR1 atuaria como modulador dessa atividade.

Ubp43 gene expression is required for normal Isg15 expression and fetal development

BACKGROUND

Isg15 covalently modifies murine endometrial proteins in response to early pregnancy. Isg15 can also be severed from targeted proteins by a specific protease called Ubp43 (Usp18). Mice lacking Ubp43 (null) form increased conjugated Isg15 in response to interferon. The Isg15 system has not been examined in chorioallantoic placenta (CP) or mesometrial (MM) components of implantation sites beyond 9.5 days post coitum (dpc). It was hypothesized that deletion of Ubp43 would cause disregulation of Isg15 in implantation sites, and that this would affect pregnancy rates.

METHODS

Heterozygous (het) Ubp43 mice were mated and MM and CP implantation sites were collected on 12.5 and 17.5 days post-coitum (dpc).

RESULTS

Free and conjugated Isg15 were greater on 12.5 versus 17.5 dpc in MM. Free and conjugated Isg15 were also present in CP, but did not differ due to genotype on 12.5 dpc. However, null CP had greater free and conjugated Isg15 when compared to het/wt on 17.5 dpc. Null progeny died in utero with fetal genotype ratios (wt:het:null) of 2:5:1 on 12.5 and 2:2:1 on 17.5 dpc. Implantation sites were disrupted within the junctional zone and spongiotrophoblast, contained less vasculature based on lectin B4 staining and contained greater Isg15 mRNA and VEGF protein in Ubp43 null when compared to wt placenta.

CONCLUSION

It is concluded that Isg15 and its conjugates are present in implantation sites during mid to late gestation and that deletion of Ubp43 causes an increase in free and conjugated Isg15 at the feto-maternal interface. Also, under mixed genetic background, deletion of Ubp43 results in fetal death.

Recent advances in endometrial angiogenesis research

This review summarises recent research into the mechanisms and regulation of endometrial angiogenesis. Understanding of when and by what mechanisms angiogenesis occurs during the menstrual cycle is limited, as is knowledge of how it is regulated. Significant endometrial endothelial cell proliferation occurs at all stages of the menstrual cycle in humans, unlike most animal models where a more precise spatial relationship exists between endothelial cell proliferation and circulating levels of oestrogen and progesterone. Recent stereological data has identified vessel elongation as a major endometrial angiogenic mechanism in the mid-late proliferative phase of the cycle. In contrast, the mechanisms that contribute to post-menstrual repair and secretory phase remodelling have not yet been determined. Both oestrogen and progesterone/progestins appear to have paradoxical actions, with recent studies showing that under different circumstances both can promote as well as inhibit endometrial angiogenesis. The relative contribution of direct versus indirect effects of these hormones on the vasculature may help to explain their pro- or anti-angiogenic activities. Recent work has also identified the hormone relaxin as a player in the regulation of endometrial angiogenesis. While vascular endothelial growth factor (VEGF) is fundamental to endometrial angiogenesis, details of how and when different endometrial cell types produce VEGF, and how production and activity is controlled by oestrogen and progesterone, remains to be elucidated. Evidence is emerging that the different splice variants of VEGF play a major role in regulating endometrial angiogenesis at a local level. Intravascular neutrophils containing VEGF have been identified as having a role in stimulating endometrial angiogenesis, although other currently unidentified mechanisms must also exist. Future studies to clarify how endometrial angiogenesis is regulated in the human, as well as in relevant animal models, will be important for a better understanding of diseases such as breakthrough bleeding, menorrhagia, endometriosis and endometrial cancer.

Involvement of molecules related to angiogenesis, proteolysis and apoptosis in implantation in rhesus monkey and mouse

We have established the well-defined cycling, pseudo-pregnant and pregnant rhesus monkey models, and used these to analyze expression of the common molecules specifically related to angiogenesis, apoptosis or proteolysis, such as vascular endothelial growth factor (VEGF) and its receptors KDR, flt-1, flt-4 and flk-1, basic fibroblast growth factor (bFGF) and its receptors Flg, transforming growth factor-alpha and beta1 (TGF-a/beta1), and TGF-beta1 receptor type I (TbetaR-I) and type II (TbetaR-II), as well as steroidogenic acute regulatory protein (StAR), tissue type plasminogen activator/urokinase plasminogen activator/plasminogen activator inhibitor type 1 (tPA/uPA/PAI-1) and matrix matalloproteinase type 1, -3/tissue inhibitor matalloproteinase type 1, -2, -3 (MMP-1, -3/TIMP-1, -2, -3), Fas/FasL, BcL-2/Bax, in the corpus luteum (CL), in the functional layer of the endometrium and in the materno-fetal boundary of the implantation site. We have demonstrated that: expression of these molecules in the monkey CL, endometrium and materno-fetal boundary of the implantation site is correlated well with CL functional and vascular development and with the processes involved in the establishment of the implantation window as well as with the early stages of placentation. A coordinated increase in tPA and its inhibitor PAI-1 expression in the monkey and rat CL may be instrumental in initiating luteal regression in both species, and correlated well with the timing of the closure of the implantation window, whereas high uPA activity in the CL is important for the early formation of the CL and for maintaining its function which is closely correlated to the period of establishment of the implantation window. Apoptosis, proteolysis and angiogenesis occur in the CL and in the endometrium during the time of establishment of the implantation window, as well as in the materno-fetal boundary of the implantation site at the early stages of placentation. It seems that these processes occur in these tissues in a coordinated and time- and cell-dependent manner, and are reliant on each other. Based on these observations, we have designed experiments to test the actions of some related available compounds on mouse implantation, used alone or in combination. The preliminary data showed that the compounds which could effectively affect apoptosis, angiogenesis or proteolysis in the implantation site were capable of effectively inhibiting implantation by acting on the endometrium and/or on the CL. Furthermore, the combined use of these compounds produced an obvious additive effect on inhibiting implantation. This finding suggested this may be a good approach for developing an anti-implantation agent.