Fetal Diagnosis and Therapy

<b><i>Objective:</i></b> We tested the feasibility of the in vitro culture of fetal nucleated erythroblasts from maternal blood for noninvasive prenatal screening as a substitute for culturing fetal nucleated erythroblasts from fetal villi. <b><i>Method:</i></b> Nucleated blood cells separated via Percoll from 52 samples of fetal villi and maternal peripheral blood were cultured with or without magnetic-activated cell sorting glycophorin A (MACS-GPA+), and detected by an anti-hemoglobin-epsilon (FITC) antibody. Gender of the epsilon-positive cells were identified by FISH and further confirmed by PCR of the villi karyotype. Developmental stages of nucleated erythroblasts from villi and blood with MACS-GPA+ were analyzed by Wright-Giemsa staining. <b><i>Results:</i></b> In the maternal blood, epsilon-positive cells were found in 4 and 24 cultured samples with and without MACS-GPA+, respectively. Also, Y-signals were visualized in 3 out of 4 and in 15 out of 24 cases in the epsilon-positive cells. Although epsilon-positive cells were found in all villus samples irrespective of MACS-GPA+ sorting, Y-signals were visualized in 31 out of 52 cases. Proerythroblasts and basophilic erythroblasts occupied 7 and 1% in fetal and maternal samples (with MACS-GPA+), respectively. <b><i>Conclusions:</i></b> The in vitro culturing of fetal nucleated erythroblasts from maternal blood is not feasible with the current techniques for prenatal diagnosis, because the fetal nucleated erythroblast is not well developed in vitro. This may be attributed to the low proportion of these erythroblasts at an early stage in the fetal circulation and the low permeability of these cells to the maternal blood.

In spite of active perinatal management, twin-twin transfusion syndrome (TTTS) remains a severe disease with a high risk of neonatal mortality and morbidity. TTTS initially results from an unbalanced blood flow from a donor to a recipient twin. However, its pathogenesis remains unclear, although cardiovascular disturbances and regulation of fetal volemia and diuresis seem central in this syndrome. Previously, we demonstrated that the renin-angiotensin system (RAS) was up-regulated in donor twins as a consequence of hypovolemia, and down-regulated in recipients. This was the first evidence of the implication of the RAS in TTTS. We hypothesize that the RAS plays a key role in the pathogenesis of TTTS. In the donor, RAS up-regulation aggravates oligohydramnios and may increase arterial resistance, which could contribute to placental dysfunction leading to intrauterine growth restriction. In the recipient, paradoxical RAS activation, due to transfer of effectors such as angiotensin II through placental shunts, could explain fetal vascular disturbances and cardiomyopathy. According to our hypothesis, TTTS would appear similar to the classical model of hypertension referred to as ‘2 kidneys-1 clip’ with a donor twin, comparable to the clipped kidney, intoxicating its cotwin, comparable to the normal kidney.

<b><i>Objective:</i></b> To compare the effect of early administration of aspirin on the risk of preterm and term preeclampsia. <b><i>Method:</i></b> A systematic review and meta-analysis of randomized controlled trials were performed. Women who were randomized to low-dose aspirin or placebo/no treatment at or before 16 weeks of gestation were included. The outcomes of interest were preterm preeclampsia (delivery <37 weeks) and term preeclampsia. Pooled relative risks (RR) with their 95% confidence intervals (CI) were computed. <b><i>Results:</i></b> The search identified 7,941 citations but only five trials on a combined total of 556 women fulfilled the inclusion criteria. When compared to controls, aspirin initiated ≤16 weeks of gestation was associated with a major reduction of the risk of preterm preeclampsia (RR 0.11, 95% CI 0.04–0.33) but had no significant effect on term preeclampsia (RR 0.98, 95% CI 0.42–2.33). <b><i>Conclusion:</i></b> Low-dose aspirin administrated at or before 16 weeks of gestation reduces the risk of preterm but not term preeclampsia.

Small fetuses are defined as those with an ultrasound estimated weight below a threshold, most commonly the 10th centile. The first clinically relevant step is the distinction of ‘true' fetal growth restriction (FGR), associated with signs of abnormal fetoplacental function and poorer perinatal outcome, from constitutional small-for-gestational age, with a near-normal perinatal outcome. Nowadays such a distinction should not be based solely on umbilical artery Doppler, since this index detects only early-onset severe forms. FGR should be diagnosed in the presence of any of the factors associated with a poorer perinatal outcome, including Doppler cerebroplacental ratio, uterine artery Doppler, a growth centile below the 3rd centile, and, possibly in the near future, maternal angiogenic factors. Once the diagnosis is established, differentiating into early- and late-onset FGR is useful mainly for research purposes, because it distinguishes two clear phenotypes with differences in severity, association with preeclampsia, and the natural history of fetal deterioration. As a second clinically relevant step, management of FGR and the decision to deliver aims at an optimal balance between minimizing fetal injury or death versus the risks of iatrogenic preterm delivery. We propose a protocol that integrates current evidence to classify stages of fetal deterioration and establishes follow-up intervals and optimal delivery timings, which may facilitate decisions and reduce practice variability in this complex clinical condition.

<b><i>Introduction:</i></b> Fetal amniotic membranes (FM) have been shown to preserve spinal cord histology in the fetal sheep model of myelomeningocele (MMC). This study compares the effectiveness of placenta-derived mesenchymal stromal cells (PMSCs) from early-gestation versus term-gestation placenta to augment FM repair to improve distal motor function in a sheep model. <b><i>Methods:</i></b> Fetal lambs (n = 4) underwent surgical MMC creation followed by repair with FM patch with term-gestation PMSCs (n = 1), FM with early-gestation PMSCs (n = 1), FM only (n = 1), and skin closure only (n = 1). Histopathology and motor assessment was performed. <b><i>Results:</i></b> Histopathologic analysis demonstrated increased preservation of spinal cord architecture and large neurons in the lamb repaired with early-gestation cells compared to all others. Lambs repaired with skin closure only, FM alone, and term-gestation PMSCs exhibited extremely limited distal motor function; the lamb repaired with early-gestation PMSCs was capable of normal ambulation. <b><i>Discussion:</i></b> This pilot study is the first in vivo comparison of different gestational-age placenta-derived stromal cells for repair in the fetal sheep MMC model. The preservation of large neurons and markedly improved motor function in the lamb repaired with early-gestation cells suggest that early-gestation placental stromal cells may exhibit unique properties that augment in utero MMC repair to improve paralysis.

The purpose of this investigation was to compare the efficacy of conventional ultrasonographic measurements (i.e. head to abdomen circumference ratio, amount of amniotic fluid) with Doppler ultrasonography in the differential diagnosis of small-for-gestational age (SGA) fetuses. Blood flow velocity waveforms were recorded from the umbilical artery descending aorta and internal carotid artery in 121 intrauterine growth-retarded fetuses and the pulsatility index was evaluated as an index of vascular impedance. Conventional ultrasonographic measurements were of limited usefulness in the differential diagnosis, whereas the ratio between the pulsatility indexes from umbilical and carotid arteries proved to be a good index for discriminating SGA fetuses due to low growth potential (congenital infections, strucutural anomalies, chromosomal abnormalities, constitutional factors) from those caused by placental dysfunction (specificity 96.6%, sensitivity 89%, positive predictive value 98.7%, negative predictive value 74.3% and accuracy 90.9%).