Preferential streaming of the ductus venosus toward the right atrium is associated with a worse outcome despite a higher rate of invasive procedures in human fetuses with left diaphragmatic hernia.

PURPOSE: Preferential streaming of the ductus venosus (DV) toward the right atrium has been observed in fetuses with left diaphragmatic hernia (LDH). The purpose of this retrospective study was to compare survival rates to discharge between a group with preferential streaming of the DV toward the right heart and a group in which this abnormal flow pattern was not present. MATERIALS AND METHODS: We retrospectively searched our patient records for fetuses with LDH in whom liver position, DV streaming and postnatal outcome information was available. 55 cases were found and divided into two groups: Group I fetuses exhibited abnormal DV streaming toward the right side of the heart; group II fetuses did not. Various prognostic and outcome parameters were compared. RESULTS: 62 % of group I fetuses and 88 % of group II fetuses survived to discharge (p = 0.032). Fetoscopic tracheal balloon occlusion (FETO) was performed in 66 % of group I fetuses and 23 % of group II fetuses (p = 0.003). Postnatal ECMO therapy was performed in 55 % of group I fetuses and 23 % of group II infants (p = 0.025). Moderate to severe chronic lung disease in survivors was observed in 56 % of the survivors of group I and 9 % of the survivors of group II (p = 0.002). CONCLUSION: Preferential streaming of the DV toward the right heart in human fetuses with left-sided diaphragmatic hernia was associated with a poorer postnatal outcome despite a higher rate of invasive pre- and postnatal procedures compared to fetuses without this flow abnormality. Specifically, abnormal DV streaming was found to be an independent predictor for FETO.

Cardiovascular transition to extrauterine life in growth-restricted neonates: relationship with prenatal Doppler findings.

OBJECTIVE: Cardiovascular status in fetal growth restriction (FGR) can be classified by the severity of individual Doppler abnormalities (early and late) or by the rate of clinical progression. We tested the hypothesis that aspects of the fetal cardiovascular status in FGR affect neonatal cardiovascular findings. STUDY DESIGN: FGR cases [abdominal circumference <5th percentile and an elevated umbilical (MCA) artery (UA) pulsatility index] had UA, middle cerebral artery and ductus venosus (DV) Doppler. Positive UA end-diastolic velocity and/or a low MCA pulsatility index denoted early and absent/reversed UA end-diastolic velocity, whereas an increased DV pulsatility index for veins denoted late responses. The rate of progression was classified into mild, progressive and severe. After delivery, shunt dynamics and blood flow across the patent ductus arteriosus (PDA), foramen ovale and atriaventricular valves, myocardial contractility and pharmacologic pressor requirement were noted at neonatal echocardiography. These findings were related to prenatal Doppler parameters. RESULTS: In 94 patients, only individual Doppler parameters related to neonatal echocardiographic findings. Absent/reversed UA DV significantly predicted PDA with right to left shunt (p = 0.016). The pressor need for cardiovascular instability was observed in neonates with abnormal prenatal DV Doppler and with lower birth weights delivered at earlier gestational age (p < 0.0001 for both). Pressor need was significantly related to neonatal death (Nagelkerke R² = 0.35, p = 0.002). CONCLUSION: A markedly abnormal UA Doppler predisposes growth-restricted neonates to persistence of fetal circulation associated with right to left shunting. Abnormal venous Doppler is a risk factor for cardiovascular instability which in turn significantly contributes to neonatal mortality. Further clarification of the neonatal cardiovascular transition may be helpful in guiding early neonatal assessment and management.

Mesodermal Pten inactivation leads to alveolar capillary dysplasia- like phenotype.

Alveolar capillary dysplasia (ACD) is a congenital, lethal disorder of the pulmonary vasculature. Phosphatase and tensin homologue deleted from chromosome 10 (Pten) encodes a lipid phosphatase controlling key cellular functions, including stem/progenitor cell proliferation and differentiation; however, the role of PTEN in mesodermal lung cell lineage formation remains unexamined. To determine the role of mesodermal PTEN in the ontogeny of various mesenchymal cell lineages during lung development, we specifically deleted Pten in early embryonic lung mesenchyme in mice. Pups lacking Pten died at birth, with evidence of failure in blood oxygenation. Analysis at the cellular level showed defects in angioblast differentiation to endothelial cells and an accompanying accumulation of the angioblast cell population that was associated with disorganized capillary beds. We also found decreased expression of Forkhead box protein F1 (Foxf1), a gene associated with the ACD human phenotype. Analysis of human samples for ACD revealed a significant decrease in PTEN and increased activated protein kinase B (AKT). These studies demonstrate that mesodermal PTEN has a key role in controlling the amplification of angioblasts as well as their differentiation into endothelial cells, thereby directing the establishment of a functional gas exchange interface. Additionally, these mice could serve as a murine model of ACD.

Gene expression analysis in hypoplastic lungs in the nitrofen model of congenital diaphragmatic hernia.

BACKGROUND: Pulmonary hypoplasia and persistent pulmonary hypertension are the main causes of mortality and morbidity in newborns with congenital diaphragmatic hernia (CDH). Nitrofen is well known to induce CDH and lung hypoplasia in a rat model, but the mechanism remains unknown. To increase the understanding of the underlying pathogenesis of CDH, we performed a global gene expression analysis using microarray technology. METHODS: Pregnant rats were given 100 mg nitrofen on gestational day 9.5 to create CDH. On day 21, fetuses after nitrofen administration and control fetuses were removed; and lungs were harvested. Global gene expression analysis was performed using Affymetrix Platform and the RAE 230 set arrays. For validation of microarray data, we performed real-time polymerase chain reaction and Western blot analysis. RESULTS: Significantly decreased genes after nitrofen administration included several growth factors and growth factors receptors involved in lung development, transcription factors, water and ion channels, and genes involved in angiogenesis and extracellular matrix. These results could be confirmed with real-time polymerase chain reaction and protein expression studies. CONCLUSIONS: The pathogenesis of lung hypoplasia and CDH in the nitrofen model includes alteration at a molecular level of several pathways involved in lung development. The complexity of the nitrofen mechanism of action reminds of human CDH; and the picture is consistent with lung hypoplasia and vascular disease, both important contributors to the high mortality and morbidity in CDH. Increased understanding of the molecular mechanisms that control lung growth may be the key to develop novel therapeutic techniques to stimulate pre- and postnatal lung growth.

Alpha-smooth muscle actin distribution in the pulmonary vasculature comparing hypoplastic and normal fetal lungs.

We investigated the intra-acinar pulmonary vascular muscularization in the developing human fetal lung between the 17th and 24th gestational weeks, that is, during the canalicular phase of lung development. Fifteen hypoplastic and 25 normal developed lungs were included in this study using monoclonal alpha-smooth muscle (sm) actin antibodies for smooth muscle detection. Computer-aided image analysis was performed for morphometrical measurements and statistical evaluation. Alpha-sm-actin-immunoreactive intra-acinar vessels down to a luminal diameter of less than 10 microns were detected in hypoplastic as well as in normally developed lungs. Crucial differences presented as follows: significantly higher density of intra-acinar vessels, especially due to alpha-sm-actin-negative vessels less than 30 microns in luminal diameter, in the control group; significantly higher alpha-sm-actin immunore-activity per section unit as well as per vessel in the hypoplastic lung group. As suggested by others, alpha-sm-actin-positive cells of the intra-acinar vessel wall in the developing human lung were demonstrated to be smooth muscle cells, their immediate precursors, and pericytes. We conclude that the increased alpha-sm-actin immunoreactivity represents muscularization of the vessel wall in functional terms and may be regarded as one structural cause among others for the establishment of persistent fetal circulation in hypoplastic lungs.