Does a large abdominal wall defect affect lung growth?

Experimental Induction of Complex Gastroschisis in the Fetal Lamb: Systematic Review

We systematically reviewed experiments in the fetal lamb model of gastroschisis using PubMed, Embase, Web of Science, and Scopus, seeking for standardized surgical techniques to obtain complex gastroschisis. Eligible were studies where an abdominal wall defect was surgically induced and gross anatomical findings at birth were available. The primary outcome was complex gastroschisis, defined by the presence of bowel stenosis, atresia, volvulus, perforation, and/or necrosis. Secondary outcomes were fetal death and additional readouts reported. Of ten eligible studies, six included lambs that had no additional prenatal manipulations and were assessed at term (35 lambs). Gastroschisis was induced at day 70-80 (term = 140-145), typically (n = 4/6 studies) in the left lower abdomen with defect size ranging from 0.5 to 4.0 cm. Only one study, in which a 1.5 cm diameter silicone ring was utilized, resulted in complex gastroschisis in 100% of term survivors. Fetal loss was more frequent in studies where a silicone ring and/or a right-sided defect were used. No changes unique to complex gastroschisis were identified in additional readouts, including bowel histology. When gastroschisis becomes "complex" following induction is uncertain. This knowledge is essential in studying potential prenatal interventions that may change the natural course.

Three-Dimensional Ultrasound Evaluation of Lung Volume in Fetuses with Abdominal Wall Defect

INTRODUCTION

Abdominal wall defects (AWDs) interfere with postnatal respiratory parameters. We aimed to evaluate lung volume (LV) in fetuses with AWD using three-dimensional (3D) ultrasound (US) and to correlate AWD with the type (omphalocele and gastroschisis) and size of the defect and neonatal morbidity and mortality.

METHODS

This prospective observational study included 72 pregnant women with fetuses with AWD and a gestational age <25 weeks. The data on abdominal volume, 3D US LV, and herniated volume were acquired every 4 weeks up to 33 weeks. LV was compared with normal reference curves and correlated with abdominal and herniated volumes.

RESULTS

Omphalocele (p < 0.001) and gastroschisis (p < 0.001) fetuses had smaller LV than normal fetuses. LV was positively correlated with abdominal volume (omphalocele, r = 0.86; gastroschisis, r = 0.88), whereas LV was negatively correlated with omphalocele-herniated volume/abdominal volume (p < 0.001, r = -0.51). LV was smaller in omphalocele fetuses that died (p = 0.002), were intubated (p = 0.02), or had secondary closure (p < 0.001). In gastroschisis, a smaller LV was observed in fetuses discharged using oxygen (p = 0.002).

CONCLUSION

Fetuses with AWD had smaller 3D LV than normal fetuses. Fetal abdominal volume was inversely correlated with LV. In omphalocele fetuses, a smaller LV was associated with neonatal mortality and morbidity.

Giant omphalocele associated pulmonary hypertension: A retrospective study

BACKGROUND

Omphalocele is a common congenital defect of the abdominal wall, management of giant omphalocele (GO) is particularly for pediatric surgeons and neonatologists worldwide. The current study aimed to review and summarize the clinical features and prognosis in neonates with GO complicated with pulmonary hypertension (PH), which is associated with increased mortality, while in hospital.

MATERIALS AND METHODS

Medical records of infants with GO between July 2015 and June 2020 were retrospectively analyzed. The patients enrolled were divided into PH and non-PH groups based on the presence or absence of PH, and patients with PH were divided into death and survival groups based on survival status. Clinical characteristics and outcomes were compared between groups, respectively. The risk factors for PH were analyzed by binary logistic regression.

RESULTS

In total, 67 neonates were identified as having GO and 24 (35.8%) were complicated with PH. Infants with PH were associated with intubation within 24 h after birth (p = 0.038), pulmonary dysplasia (p = 0.020), presence of patent ductus arteriosus (PDA; p = 0.028), a staged operation (p = 0.002), longer mechanical ventilation days (p < 0.001), oxygen requirement days (p < 0.001), parenteral nutrition (PN) days (p < 0.001), length of neonatal intensive care unit (NICU) or hospital stay (p = 0.001 and 0.002, respectively), and mortality (p = 0.001). The results of multivariable logistic regression analysis revealed that a staged operation was independently associated with PH. In addition, PH patients with lower birth weight, higher peak of pulmonary arterial systolic pressure, and refractory to pulmonary vasodilators (PVD) had increased mortality.

CONCLUSION

Pulmonary hypertension is a serious complication and significantly increases the mortality and morbidities in infants with a GO. In addition, early and serial assessment of PH by echocardiography should be a routine screening scheme, especially in the neonatal omphalocele population who required a staged surgical repair. Clinicians should be aware that infants with PH who had low weight, severe and refractory PH have a higher risk of death.

Muscle imbalance as a cause of scoliosis: a study in a fetal lamb abdominal wall defect model

BACKGROUND

We created abdominal wall defects (AWD) in fetal lambs to investigate possible causes of scoliosis.

METHODS

We incised the upper abdominal wall (including Rectus) in 60-day gestation fetal lambs, from the midline to either the right (Group A) or left (Group B) costal margin, in 14 lambs carried by 7 ewes. They were delivered by cesarean section at term (about 145 days). Scoliosis was evaluated by anterio-posterior X-rays, determining the Cobb angle.

RESULTS

Four fetuses in Group A and 3 in Group B survived. There were 3 successful AWD lambs Group A and 2 in Group B. One lamb in each group survived with the AWD covered with a thick capsule. The convexity of spinal curve was the direction of scoliosis. Right scoliosis was only seen in the 4 Group A lambs. Left scoliosis was only seen in Group B lambs (2/3, 67%). The mean Cobb angle was 41.7 ± 11.5° in Group A and in Group B the Cobb angles were 59.6^o and 60.6°. Overall, 4/5 lambs with organ prolapse (80%) and both lambs without organ prolapse had scoliosis.

CONCLUSION

Muscle imbalance may contribute to the development of scoliosis in a fetal lamb AWD model.

Severe but not moderate hyperoxia of newborn mice causes an emphysematous lung phenotype in adulthood without persisting oxidative stress and inflammation

Background

Preterm newborns typically require supplemental oxygen but hyperoxic conditions also damage the premature lung. Oxygen-induced lung damages are mainly studied in newborn mouse models using oxygen concentrations above 75% and looking at short-term effects. Therefore, we aimed at the investigation of long-term effects and their dependency on different oxygen concentrations.

Methods

Newborn mice were exposed to moderate vs. severe hyperoxic air conditions (50 vs. 75% O₂) for 14 days followed by a longer period of normoxic conditions. Lung-related parameters were collected at an age of 60 or 120 days.

Results

Severe hyperoxia caused lower alveolar density, enlargement of parenchymal air spaces and fragmented elastic fibers as well as higher lung compliance with peak airflow limitations and higher sensitivity to ventilation-mediated damages in later life. However, these long-term lung structural and functional changes did not restrict the voluntary physical activity. Also, they were not accompanied by ongoing inflammatory processes, increased formation of reactive oxygen species (ROS) or altered expressions of antioxidant enzymes (superoxide dismutases, catalase) and lung elasticity-relevant proteins (elastin, pro-surfactant proteins) in adulthood. In contrast to severe hyperoxia, moderate hyperoxia was less lung damaging but also not free of long-term effects (higher lung compliance without peak airflow limitations, increased ROS formation).

Conclusions

Severe but not moderate neonatal hyperoxia causes emphysematous lungs without persisting oxidative stress and inflammation in adulthood. As the existing fragmentation of the elastic fibers seems to play a pivotal role, it indicates the usefulness of elastin-protecting compounds in the reduction of long-term oxygen-related lung damages.

Evaluation of alveolar epithelial cells in the sheep model of congenital diaphragmatic hernia: Type 1 alveolar epithelial cells and histopathological image analysis

BACKGROUND

There are few reports comparing type 1 alveolar epithelial cell development with histopathological image analysis. We investigated these as indicators of maturity in fetal lambs' lungs in a congenital diaphragmatic hernia (CDH) model.

METHODS

We created left CDH in 4 fetal lambs at 75 or 76days' gestation (Group A). Controls were 5 sham-operated lambs (Group B); both groups delivered at term. The right lower lung lobe (RLL) and left lower lobe (LLL) were sampled. Using histopathological image analysis, alveoli/air sacs count (AC), alveoli/air sacs area percentage (AP), average area (AA), total area (TA), and perimeter (PM) were determined. We also evaluated total lung volumes, radial alveolar count (RAC), and Type 1 alveolar epithelial cells ratio (AT1 ratio), which we previously reported. Regression analysis was performed, with p<0.05 considered significant.

RESULTS

RLL and LLL AT1 ratio and LLL RAC in Group A were lower than in Group B. There are no significant differences demonstrated by histopathological image analysis. In Group A, the AT1 ratio in the LLL was lower than in the RLL. There were no differences between LLL and RLL in Group B.

CONCLUSION

AT1 ratio was superior to the other indicators evaluating lung maturity.