Diagnosis and management of fetal growth restriction: the role of fetal therapy

The Effect of an Early Life Motor Skill Intervention on Physical Activity in Growth-Restricted Mice

INTRODUCTION

Early life growth restriction significantly increases the risk of adulthood physical inactivity and thereby chronic disease incidence. Improvements in motor skill acquisition could result in greater physical activity engagement in the growth-restricted population, thus reducing chronic disease risk. The purpose of this study was to implement an early life motor training intervention to improve physical activity engagement in control and growth-restricted mice.

METHODS

Mice were growth restricted in early life utilizing a validated nutritive model or remained fully nourished in early life as a control. All mice were tested throughout early life for various components of motor skill acquisition. On postnatal day 10, mice were randomly assigned to engage in an early life motor skill intervention daily until postnatal day 21 or remained as a sedentary control. All mice were given access to an in-cage running wheel from postnatal days 45-70.

RESULTS

Growth-restricted group (PGR) mice had impaired trunk and postural control, coordination/vestibular development, and hindlimb strength in early life compared with control mice. There were no differences in wheel running behavior between the trained and sedentary mice, although control mice ran at a faster average speed compared with PGR mice. Control female mice ran more than PGR female mice during the week 2 dark cycle.

CONCLUSIONS

Early life growth restriction reduced motor skill attainment throughout early life, which may be associated with reduced ability to engage in physical activity in adulthood. The early life motor skill intervention did not elicit changes in body weight or physical activity engagement in control or PGR mice, indicating that a more intense/different intervention specifically targeting skeletal muscle may be necessary to counteract the detrimental effects of early life growth restriction.

Tadalafil for Treatment of Fetal Growth Restriction: A Review of Experimental and Clinical Studies

Fetal growth restriction (FGR) is a major concern in perinatal care. Various medications have been proposed as potential treatments for this serious condition. Nonetheless, there is still no definitive treatment. We studied tadalafil, a phosphodiesterase-5 inhibitor, as a therapeutic agent for FGR in clinical studies and animal experiments. In this review, we summarize our preclinical and clinical data on the use of tadalafil for FGR. Our studies in mouse models indicated that tadalafil improved FGR and hypertensive disorders of pregnancy. A phase II trial we conducted provided evidence supporting the efficacy of tadalafil in prolonging pregnancy (52.4 vs. 36.8 days; p = 0.03) and indicated a good safety profile for fetuses and neonates. Fetal, neonatal, and infant mortality was significantly lower in mothers receiving tadalafil treatment than that in controls (total number: 1 vs. 7, respectively; p = 0.03), and no severe adverse maternal events associated with tadalafil were observed. Although further studies are needed to establish the usefulness of tadalafil in FGR treatment, our research indicates that the use of tadalafil in FGR treatment may be a paradigm shift in perinatal care.

Fetal Biometric Assessment and Infant Developmental Prognosis of the Tadalafil Treatment for Fetal Growth Restriction

Background and Objectives: Tadalafil is expected to treat fetal growth restriction (FGR), a risk factor for stillbirth and neonatal morbidity. This study aimed to evaluate the fetal biometric growth pattern of fetuses with FGR treated with tadalafil by ultrasonographic assessment. Materials and Methods: This was a retrospective study. Fifty fetuses diagnosed with FGR and treated by maternal administration of tadalafil and ten controls who received conventional treatment at Mie University Hospital from 2015 to 2019 were assessed. Fetal biparietal diameter (BPD), head circumference (HC), abdominal circumference (AC), femur length (FL), and estimated fetal weight (EFW) at the start of treatment and at two weeks and four weeks of treatment were mainly assessed by ultrasound examination. The Wilcoxon signed-rank test was used to assess the measures. The Kyoto Scale of Psychological Development (KSPD) was used to assess the developmental prognosis on tadalafil-treated children at 1.5 years of corrected age (CA) and 3 years old. Results: The median gestational age at the start of treatment was 30 and 31 weeks in the tadalafil and control groups, respectively, and the median gestational age at delivery was 37 weeks in both groups. The Z-score of HC was significantly increased at 4 weeks of treatment (p = 0.005), and the umbilical artery resistance index was significantly decreased (p = 0.049), while no significant difference was observed in the control group. The number of cases with an abnormal score of less than 70 on the KSPD test was 19% for P-M, 8% for C-A, 19% for L-S, and 11% for total area at 1.5 years CA. At 3 years old, the respective scores were 16%, 21%, 16%, and 16%. Conclusions: Tadalafil treatment for FGR may maintain fetal HC growth and infants' neuro-developmental prognosis.

Umbilical Cord Blood-Derived Exosomes in Maternal-Fetal Disease: a Review

The nutrients and other factors transported by umbilical cord blood, which is vital for fetal survival, play crucial roles in fetal development. There are various communication modes between the fetal-placental system and the maternal-placental system, and these communication modes are all mediated by umbilical cord blood. During the process of umbilical cord blood transportation, the changes of some nutrients and factors may play a key role in fetal development. Exosomes, which are members of the extracellular vesicle family, are present in the umbilical cord blood and play roles in information transmission as a result of their efficient cellular communication activity. The study of umbilical cord blood-derived exosomes provides a new approach for research on the etiology of maternal-fetal diseases and they may be useful for the development of intrauterine treatments. This review summarizes specific functions and research directions regarding umbilical cord blood-derived exosomes, and their potential associations with pregnancy complications.

Tadalafil treatment for fetuses with early-onset growth restriction: a protocol for a multicentre, randomised, placebo-controlled, double-blind phase II trial (TADAFER IIb)

INTRODUCTION

TheTADAlafil treatment for Fetuses with early-onset growth Restriction: multicentrer, randomizsed, phase II trial (TADAFER II) study showed the possibility of prolonging the pregnancy period in cases of early-onset fetal growth restriction; however, it was an open-label study. To establish further evidence for the efficacy of tadalafil in this setting, we planned a multicentre, randomised, placebo-controlled, double-blind trial.

METHODS AND ANALYSIS

This trial will be conducted in 180 fetuses with fetal growth restriction enrolled from medical centres in Japan; their mothers will be randomised into three groups: arm A, receiving two times per day placebo; arm B, receiving one time per day 20 mg tadalafil and one time per day placebo and arm C, receiving 20 mg two times per day tadalafil. The primary endpoint is the prolongation of gestational age at birth, defined as days from the first day of the protocol-defined treatment to birth. To minimise bias in terms of fetal baseline conditions and timing of delivery, a fetal indication for delivery as in TADAFER II will be established in this trial. The investigator will evaluate fetal baseline conditions at enrolment and decide the timing of delivery based on this indication.

ETHICS AND DISSEMINATION

This study has been approved by Mie University Hospital Clinical Research Review Board on 22 July 2019 (S2018-007). Written informed consent will be obtained from all mothers before recruitment. Our findings will be widely disseminated through peer-reviewed publications.

TRIAL REGISTRATION

jRCTs041190065.

Maternal blood concentration of tadalafil in pregnancy: Comparison of pregnant and non-pregnant women

OBJECTIVE

In this study, the drug kinetics of tadalafil were compared between pregnant and non-pregnant women to determine the ideal dosage to promote uterine blood flow.

MATERIALS AND METHODS

We recruited five pregnant and five non-pregnant women, all of which were administered tadalafil (20 mg/day). The blood concentration of tadalafil was measured 1, 2, 4, 6, 8, and 24 h after administration. We investigated the side effects within 4 days of tadalafil administration and compared the cumulative frequency between the two groups.

RESULTS

The mean area under the concentration-time curve and maximum blood concentration of tadalafil were not different between the pregnant and non-pregnant groups. Time to maximum blood concentration was delayed by 1 min on average in the pregnant group compared with the non-pregnant group. The cumulative frequency of side effects was significantly lower in the pregnant group than in the non-pregnant group (P = 0.026). No side effects were observed in either group after the fifth day of the tadalafil administration.

CONCLUSION

Although there was no difference in maximum blood concentration between non-pregnant and pregnant women, the rate of side effects was lower in pregnant women than in non-pregnant women. Therefore, pregnant women may tolerate tadalafil better.

Assessment of the value of measuring soluble fms-like tyrosine kinase-1 and placental growth factor levels following administration of tadalafil to treat fetal growth restriction

PURPOSE

The aim of this study was to measure the blood levels of soluble fms-like tyrosine kinase-1 (sFlt-1) and placental growth factor (PlGF) before and after tadalafil treatment in patients with fetal growth restriction.

MATERIALS AND METHODS

Maternal blood was collected from 13 women before and 2 weeks after tadalafil administration in the TADAFER II trial. The tadalafil treatment was conducted in addition to the conventional FGR treatment. As a control, maternal blood was also collected from 11 women before and 2 weeks after conventional treatment for fetal growth restriction. Blood sFlt-1 and PlGF were measured and the sFlt-1/PlGF ratio was calculated. Student's t-test was used to statistically analyze differences in the sFlt-1 and PlGF levels, and in the sFlt-1/PlGF ratios.

RESULTS

In both treatment groups, the levels of sFlt-1 and PlGF before and after treatment were not significantly different from each other. The sFlt-1/PlGF ratio was 2.0 ± 1.0 before and 17.6 ± 11.3 after treatment in the control group (p=.04). The sFlt-1/PlGF ratio was 2.2 ± 1.1 before and 22.2 ± 10.6 after tadalafil treatment in the tadalafil group (p=.06). The sFlt-1/PlGF ratios before and after tadalafil treatment were significantly increased in the control group. In both treatment groups, the sFlt-1/PlGF ratios before and after treatment were less than 38.

CONCLUSIONS

We conclude that the levels of sFlt-1 and PlGF were not significantly different as a result of tadalafil treatment. Further studies are needed to understand the mechanism of action of tadalafil in the treatment of fetal growth restriction.

Tadalafil Treatment Ameliorates Hypoxia and Alters Placental Expression of Proteins Downstream of mTOR Signaling in Fetal Growth Restriction

Background and Objectives: Fetal growth restriction (FGR) is associated with fetal mortality and is a risk factor for cerebral palsy and future lifestyle-related diseases. Despite extensive research, no effective treatment strategy is available for FGR. Mammalian target of rapamycin (mTOR) signaling is important for the growth of fetal organs and its dysregulation is associated with miscarriage. Here, we focused on mTOR signaling and investigated how the activities of phospho-ribosomal protein S6 (rps6) and phospho-eukaryotic translation initiation factor 4E (eIF-4E), which act downstream of mTOR signaling in the human placenta, change following treatment of FGR with tadalafil and aimed to elucidate the underlying mechanism of action. Placental hypoxia was investigated by immunostaining for hypoxia-inducible factor (HIF)-2α. Materials and Methods: Phosphor-rps6 and phosphor-eIF4E expression were examined by Western blotting and enzyme-linked immunosorbent assay, respectively. Results: HIF-2α expression significantly increased in FGR placenta compared with that in the control placenta but decreased to control levels after tadalafil treatment. Levels of phospho-rps6 and phospho-eIF-4E were significantly higher in FGR placenta than in control placenta but decreased to control levels after tadalafil treatment. Conclusions: Tadalafil restored the levels of HIF-2α, phospho-rps6, and eIF-4E in FGR placenta to those observed in control placenta, suggesting that it could be a promising treatment strategy for FGR.

Evaluation of first-trimester neutrophil-lymphocyte ratio and platelet-lymphocyte ratio values in pregnancies complicated by intrauterine growth retardation

Objective:

The objective of this study is to compare the first-trimester hemogram parameters [neutrophil-lymphocyte ratio (NLR) and platelet-lymphocyte ratio (PLR)] of pregnant women complicated by intrauterine growth retardation (IUGR) and normal pregnant women.

Materials and Methods:

We retrospectively evaluated the medical records of pregnant women (n=50) complicated with IUGR and pregnant women in the control group (n=50).

Results:

The first-trimester NLR and PLR values of the pregnant women complicated by IUGR were 6.59±1.12 and 117.2±16.00, respectively. The first-trimester NLR and PLR values of the pregnant women in the control group were 2.84±0.55 and 112.80±13.01, respectively. There was a statistically significant difference between the two groups with respect to NLR (p<0.001).

Conclusion:

Pregnancies complicated by IUGR have high neonatal mortality and morbidity rates. Therefore, the early diagnosis of disease and appropriate management are extremely crucial for both fetal and maternal prognoses. High NLR values in the first trimester may contribute to the early diagnosis of IUGR.

Maternal Blood Concentration of Tadalafil and Uterine Blood Flow in Pregnancy

: Background and Objectives: Tadalafil for treatment of fetal growth restriction (FGR) or preeclampsia is given once a day orally. The drug kinetics of tadalafil were investigated to determine the ideal dosage to promote uterine blood flow. Materials and Methods: We recruited five pregnant women with FGR or preeclampsia before administration of tadalafil, all of which were administered tadalafil (20 mg/day, once-daily dosing). The blood concentration of tadalafil was measured 1, 2, 4, 6, 8, and 24 h after administration, and uterine blood flow was measured before tadalafil administration and 2-4 and 20-24 h after. We then analyzed the correlation between tadalafil blood concentration and uterine artery blood flow. Results: The blood concentration of tadalafil correlated with uterine artery blood flow in pregnant women. The blood concentration of tadalafil and uterine artery blood flow decreased 5 h after administration of tadalafil. Conclusions: The blood concentration of tadalafil and uterine artery blood flow fluctuate in parallel, the latter was decreased by reduced blood concentration. Thus, a study of tadalafil administered twice a day in pregnant women will be needed to stabilize uterine artery blood flow.

Safety Evaluation of Tadalafil Treatment for Fetuses with Early-Onset Growth Restriction (TADAFER): Results from the Phase II Trial

Tadalafil is a phosphodiesterase 5 (PDE5) inhibitor with a long half-life, high selectivity, and rapid onset of action. Because the safety of using PDE5 inhibitors as therapeutic agents for fetal growth restriction (FGR) has been a problem worldwide, this paper primarily focuses on the safety assessments performed in the Tadalafil Treatment for Fetuses with Early-Onset Growth Restriction (TADAFER) II population. Neonatal and maternal adverse events were analyzed, in addition to fetal, neonatal, and infant death cases, six months after stopping the trial. Eighty-nine pregnant women with FGR were studied between September 2016 and March 2018 (45 and 44 in the tadalafil and conventional treatment groups, respectively). Seven (16%) deaths (four fetal, one neonatal, and two infant) in the control group, whereas only one neonatal death occurred in the tadalafil group. Although headache, facial flushing, and nasal hemorrhage occurred more frequently in the tadalafil group, these symptoms were Grade 1 and transient. In conclusion, this trial showed that tadalafil decreased the fetal and infant deaths associated with FGR. This is thought to be primarily due to pregnancy prolongation. Further studies are warranted to evaluate the efficacy of tadalafil in treating early-onset FGR.

The role of G protein-associated estrogen receptor (GPER) 1, corin, raftlin, and estrogen in etiopathogenesis of intrauterine growth retardation

Objective: The aim of the present study was to detect the role of G protein-associated estrogen receptor (GPER) 1, corin, raftlin and estrogen in etiopathogenesis of intrauterine growth retardation (IUGR).Materials and methods: The present study was designed prospectively between January 2017 and May 2018. The study group included 32 patients with unexplained IUGR and 32 healthy pregnant women who gave birth at term among the patients who referred to obstetrics clinic of a tertiary reference hospital. Intrauterine growth retardation (IUGR) was accepted as birth weight below 10th percentile according to the estimated fetal weight. Exclusion criteria were as follows: the patients with renal or hepatic dysfunction, presence of any chronic disease, smoker patients, preeclampsia, acute or chronic inflammatory diseases, body mass index as <18 kg/m² and >25 kg/m², structural or chromosomal abnormality in fetus Estradiol (E2), estriol (E3), GPER, corin, and raftlin levels were analyzed in maternal serum and placental tissue homogenate through ELISA method.Results: Serum levels of GPER-1, raftlin, and E3 were significantly lower in IUGR group when compared with the control group (p < .05 for all). Serum corin and E2 levels were similar between two groups. GPER-1, E2, E3, raftlin, and corin levels in placental homogenate were found significantly higher in the control group (p < .05 for all).Conclusion: Although maternal, fetal, and placental causes take place in etiopathogenesis of IUGR, exact etiological factor is not revealed in majority of the IUGR cases. The present study serves as the first study revealing the role of the decrease in GPER-1 and raftlin in maternal serum and placental levels on the etiopathogenesis of IUGR. Furthermore, the decrease in placental corin expression of the cases with IUGR was detected first in the literature. The present study reveals a potential therapeutic use of GPER-1, corin, and raftlin for IUGR.

TADAFER II: Tadalafil treatment for fetal growth restriction - a study protocol for a multicenter randomised controlled phase II trial

INTRODUCTION

There is no proven therapy to reverse or ameliorate fetal growth restriction (FGR). Sildenafil, a selective phosphodiesterase 5 (PDE5) inhibitor, has been reported to potentially play a therapeutic role in FGR, but this has not been established. Tadalafil is also a selective PDE5 inhibitor. We have demonstrated the efficacy of tadalafil against FGR along with short-term outcomes and the feasibility of tadalafil treatment. Based on the hypothesis that tadalafil will safely increase the likelihood of increased fetal growth in FGR, we designed this phase II study to prospectively evaluate the efficacy and safety of tadalafil against FGR.

METHODS AND ANALYSIS

This study is a multicentre, randomised controlled phase II trial. A total of 140 fetuses with FGR will be enrolled from medical centres in Japan. Fetuses will be randomised to receive either the conventional management for FGR or a once-daily treatment with 20 mg of tadalafil along with the conventional management until delivery. The primary endpoint is fetal growth velocity from the first day of the protocol-defined treatment to birth (g/day). To minimise bias in terms of fetal baseline conditions and timing of delivery, a fetal indication for delivery was established in this study. The investigator will evaluate fetal baseline conditions at enrolment and will decide the timing of delivery based on this fetal indication. Infants will be followed up for development until 1.5 years of age.

ETHICS AND DISSEMINATION

This study was approved by the Institutional Review Board of Mie University Hospital and each participating institution. Our findings will be widely disseminated through peer-reviewed publications.

TRIAL REGISTRATION NUMBER

UMIN000023778.

Regulation of Placental Development and Its Impact on Fetal Growth-New Insights From Mouse Models

The placenta is the chief regulator of nutrient supply to the growing embryo during gestation. As such, adequate placental function is instrumental for developmental progression throughout intrauterine development. One of the most common complications during pregnancy is insufficient growth of the fetus, a problem termed intrauterine growth restriction (IUGR) that is most frequently rooted in a malfunctional placenta. Together with conventional gene targeting approaches, recent advances in screening mouse mutants for placental defects, combined with the ability to rapidly induce mutations in vitro and in vivo by CRISPR-Cas9 technology, has provided new insights into the contribution of the genome to normal placental development. Most importantly, these data have demonstrated that far more genes are required for normal placentation than previously appreciated. Here, we provide a summary of common types of placental defects in established mouse mutants, which will help us gain a better understanding of the genes impacting on human placentation. Based on a recent mouse mutant screen, we then provide examples on how these data can be mined to identify novel molecular hubs that may be critical for placental development. Given the close association between placental defects and abnormal cardiovascular and brain development, these functional nodes may also shed light onto the etiology of birth defects that co-occur with placental malformations. Taken together, recent insights into the regulation of mouse placental development have opened up new avenues for research that will promote the study of human pregnancy conditions, notably those based on defects in placentation that underlie the most common pregnancy pathologies such as IUGR and pre-eclampsia.

Retinol binding protein as early marker of fetal growth restriction in first trimester maternal serum

BACKGROUND

Serum retinol binding protein (RBP4) is the binding protein for retinol, being delivered into the circulation through the carrier protein transthyretin (TTR) together with thyroxin (T4). RBP4 has also been recently indicated as a new adipokine implicated in insulin resistance and metabolism regulation.

OBJECTIVE

To investigate the role of RBP4 as early markers of fetal growth restriction (FGR) and preeclampsia (PE) in maternal serum during the first trimester of pregnancy.

MATERIALS AND METHODS

Retrospective case control study in patients between the 12th and the 14th week of gestation. RBP4, TTR and T4 concentration was assessed in maternal serum of three groups of women: 15 and 14 patients later developing respectively FGR and PE were compared with 11 patients having a normal pregnancy.

RESULTS

All women were Caucasian and the mean maternal age was 33.62 years (±5.50). RBP4 resulted lower in the FGR than in the control group (11.00 versus 16.00 µg/ml, p < 0.05) and than in the PE group (15.00 µg/ml, p = 0.075), both in bivariate and multivariate analysis. No difference was observed in TTR and T4 concentration.

CONCLUSIONS

RBP4 seems to play a role as early marker of FGR but not PE in first trimester maternal serum.

Advances in maternal fetal medicine practice

Maternal fetal medicine (MFM) is a subspecialty of obstetrics that focuses on identified risk pregnancies. The role includes obstetric ultrasound for fetal assessment and diagnosis of anomalies, invasive prenatal diagnosis and management of pregnancies complicated by maternal medical disorders, multiple fetuses and the antenatal management of extreme prematurity. Skill specialisation within MFM includes fetal interventions such as fetal shunting procedures, intrauterine transfusion, fetoscopic laser photocoagulation of anastomotic vessels for twin to twin transfusion syndrome and ex utero intrapartum treatment. MFM specialists are actively involved in clinical and basic science research to improve maternal and neonatal outcomes. Most Australian MFM specialists are associated with metropolitan teaching hospitals. MFM sub-specialisation has reduced the impact of disability associated with aneuploidy, structural anomalies, multiple pregnancy and extreme prematurity. Management aims are to give families timely counselling, appropriate intervention, and optimisation of the time and location of delivery. The aim of this paper is to update the reader regarding current advances in MFM practices.

Histomorphometric characteristics of first trimester chorionic villi in pregnancies with low serum pregnancy-associated plasma protein-A levels: relationship with placental three-dimensional power doppler ultrasonographic vascularization

OBJECTIVE

To evaluate histomorphometric vascular characteristics from samples obtained by chorionic villus sampling (CVS) in pregnancies with low serum pregnancy-associated plasma protein-A (PAPP-A) levels and to relate these findings to three-dimensional (3D) placental volume and power Doppler vascularization.

METHODS

Immediately before CVS, placental 3D-power Doppler ultrasonography was performed at 11 + 0 to 13 + 6 weeks in 12 pregnancies with PAPP-A concentrations <0.3 multiples of median (MoM) as well as in 11 control women. Using a standardized setting placental volume, vascularization index (VI), flow index (FI), and vascularization flow index (VFI) were measured. Histomorphometric parameters of villi were blindly evaluated with a video-computerized-image-analysis system.

RESULTS

Pregnancies with low PAPP-A showed a significantly reduced number of capillary vessels per villus cross-section (p = 0.005) and a smaller capillary diameter (p = 0.041). Placental vascular indices were significantly related to the number of fetal capillary vessels per villus (VI: r = 0.51, p = 0.03; FI: r = 0.48, p = 0.04; VFI: r = 0.56, p = 0.01).

CONCLUSIONS

Differences in placental vascularization are present in first trimester in pregnancies with low PAPP-A and they are associated to altered 3D placental Doppler indices.

First-trimester umbilical vein blood flow in pregnancies with low serum pregnancy-associated plasma protein-A levels: an early predictor of fetal growth restriction

OBJECTIVE

To investigate umbilical vein blood flow (UVBF) during the first trimester in pregnancies with low serum pregnancy-associated plasma protein-A (PAPP-A) levels and to relate umbilical vein (UV) diameter, time-averaged maximum velocity (TAMXV) and UVBF values to the subsequent development of fetal intrauterine growth restriction (IUGR).

METHODS

UVBF assessment was performed at 11 + 0 to 13 + 6 weeks' gestation in 102 singleton pregnancies with PAPP-A concentrations of < 0.3 multiples of the median. UV diameter, UV-TAMXV and UVBF were calculated and analyzed in relation to pregnancy outcome.

RESULTS

Pregnancy outcomes were: 51 pregnancies with birth weight ≥ 10(th) centile (Group A), 30 pregnancies with birth weight < 10(th) centile with normal Doppler in the umbilical artery throughout gestation (Group B) and 21 pregnancies with birth weight < 10(th) centile and abnormal umbilical artery Doppler later in gestation (Group C). No differences were found in PAPP-A levels between groups. Group C fetuses exhibited significantly lower values of UV-TAMXV (z-score - 1.99 SDs, t = 8.527, P ≤ 0.0001) and UVBF (z-score - 0.97 SDs, t = 7.420, P ≤ 0.0001) in comparison with normal reference ranges, while no differences were found in Groups A or B.

CONCLUSIONS

Decreased UV-TAMXV and UVBF at 11 + 0 to 13 + 6 weeks' gestation identify fetuses at risk of developing IUGR among pregnancies with low levels of PAPP-A.