Loss of growth differentiation factor 15 exacerbates lung injury in neonatal mice

Growth differentiation factor 15 (GDF15) is a divergent member of the transforming growth factor-β (TGF-β) superfamily, and its expression increases under various stress conditions, including inflammation, hyperoxia, and senescence. GDF15 expression is increased in neonatal murine bronchopulmonary dysplasia (BPD) models, and GDF15 loss exacerbates oxidative stress and decreases cellular viability in vitro. Our overall hypothesis is that the loss of GDF15 will exacerbate hyperoxic lung injury in the neonatal lung in vivo. We exposed neonatal Gdf15-/- mice and wild-type (WT) controls on a similar background to room air or hyperoxia (95% [Formula: see text]) for 5 days after birth. The mice were euthanized on postnatal day 21 (PND 21). Gdf15-/- mice had higher mortality and lower body weight than WT mice after exposure to hyperoxia. Hyperoxia exposure adversely impacted alveolarization and lung vascular development, with a greater impact in Gdf15-/- mice. Interestingly, Gdf15-/- mice showed lower macrophage count in the lungs compared with WT mice both under room air and after exposure to hyperoxia. Analysis of the lung transcriptome revealed marked divergence in gene expression and enriched biological pathways in WT and Gdf15-/- mice and differed markedly by biological sex. Notably, pathways related to macrophage activation and myeloid cell homeostasis were negatively enriched in Gdf15-/- mice. Loss of Gdf15 exacerbates mortality, lung injury, and the phenotype of the arrest of alveolarization in the developing lung with loss of female-sex advantage in Gdf15-/- mice.NEW & NOTEWORTHY We show for the first time that loss of Gdf15 exacerbates mortality, lung injury, and the phenotype of the arrest of alveolarization in the developing lung with loss of female-sex advantage in Gdf15-/- mice. We also highlight the distinct pulmonary transcriptomic response in the Gdf15-/- lung including pathways related to macrophage recruitment and activation.

Unilateral neonatal pulmonary interstitial emphysema managed conservatively: A case report

BACKGROUND

Pulmonary interstitial emphysema (PIE) is a pathological state when air escapes from ruptured alveoli and is trapped along the sheaths surrounding the bronchovascular bundle. PIE is not uncommon in infants who require mechanical ventilation and even less common in infants on noninvasive ventilatory support; however, it is extremely unusual in infants in room air.

CASE PRESENTATION

A 2-week-old male infant developed worsening tachypnea in the special-care nursery. The patient was born at 33 weeks' gestation by induced vaginal delivery due to pre-eclampsia. He required positive pressure ventilation at birth and was admitted to the neonatal intensive care unit on nasal continuous positive airway pressure. On the second day of life, exogenous surfactant was administered via endotracheal tube due to increased oxygen requirement, and, soon after, he was weaned off all respiratory support. After 10 days of stability, he developed tachypnea with diminished air entry on the left side of the chest. Chest radiograph and chest computerized tomography confirmed left-sided unilateral PIE. The patient was treated conservatively with positional therapy alone. Significant clinical and radiographic improvement was noticed within 4 days; almost complete resolution by 10 days and the infant was discharged 23 days later. At follow-up at 7 months, the infant was found to be symptom-free with a normal chest radiograph.

CONCLUSIONS

Traditional management of unilateral PIE generally involves a combination of invasive ventilatory support and positional therapy to break the vicious cycle pathophysiology of PIE. This report focuses on the insidious progression of PIE in nonventilated neonates and describes a nontraditional conservative management strategy for the management of unilateral PIE.

Role of Growth Differentiation Factor 15 in Lung Disease and Senescence: Potential Role Across the Lifespan

Growth Differentiation Factor 15 (GDF15) is a divergent member of transforming growth factor-beta (TGF-β) superfamily and is ubiquitously expressed, under normal physiological conditions. GDF15 expression increases during many pathological states and serves a marker of cellular stress. GDF15 has multiple and even paradoxical roles within a pathological condition, as its effects can be dose- and time-dependent and vary based on the targeted tissues and downstream pathways. GDF15 has emerged as one of the most recognized proteins as part of the senescence associated secretory phenotype. Cellular senescence plays a major role in many lung diseases across the life-span from bronchopulmonary dysplasia in the premature neonate to COPD and idiopathic pulmonary fibrosis in aged adults. GDF15 levels have been reported to be as a useful biomarker in chronic obstructive pulmonary disease, lung fibrosis and pulmonary arterial hypertension and predict disease severity, decline in lung function and mortality. Glial-cell-line-derived neurotrophic factor family receptor alpha-like (GFRAL) in the brain stem has been identified as the only validated GDF15 receptor and mediates GDF15-mediated anorexia and wasting. The mechanisms and pathways by which GDF15 exerts its pulmonary effects are being elucidated. GDF15 may also have an impact on the lung based on the changes in circulating levels or through the central action of GDF15 activating peripheral metabolic changes. This review focuses on the role of GDF15 in different lung diseases across the lifespan and its role in cellular senescence.

Fetal exposure to mercury and lead from intrauterine blood transfusions

BACKGROUND

Mercury (Hg) and lead (Pb) exposure during childhood is associated with irreversible neurodevelopmental effects. Fetal exposure to Hg and Pb from intrauterine blood transfusion (IUBT) has not been reported.

METHODS

Fetal exposure was estimated based on transfusion volume and metal concentration in donor packed red blood cell (PRBCs). As biomarkers to quantify prenatal exposure are unknown, Hg and Pb in donor PRBCs were compared to estimated intravenous (IV) RfDs based on gastrointestinal absorption.

RESULTS

Three pregnant women received 8 single-donor IUBTs with volumes ranging from 19 to 120 mL/kg. Hg and Pb were present in all donor PRBC units. In all, 1/8 IUBT resulted in Hg dose five times higher than the estimated IV RfD. Median Pb dose in one fetus who received 5 single-donor IUBTs between 20-32 weeks gestation was 3.4 μg/kg (range 0.5-7.9 μg/kg). One donor unit contained 12.9 μg/dL of Pb, resulting in a fetal dose of 7.9 μg/kg, 40 times higher than the estimated IV RfD at 20 weeks gestation.

CONCLUSION

This is the first study documenting inadvertent exposure to Hg and Pb from IUBT and quantifying the magnitude of exposure. Screening of donor blood is warranted to prevent toxic effects from Hg and Pb to the developing fetus.

Knowledge of periconceptional folic acid use among pregnant women at Ain Shams University Hospital, Cairo, Egypt

Egypt has a high incidence of neural tube defects. Folic acid supplementation in the periconceptional period is known to lower the risk of such defects. This cross-sectional study aimed to measure the level of knowledge about periconceptional folic acid use among pregnant women attending for antenatal care at Ain Shams University Hospital, Cairo, Egypt in 2012. Questionnaires were filled through personal interviews with 660 pregnant women. Of the respondents, 62.4% had heard of folic acid and 39.2% knew about the role of folic acid supplementation in prevention of congenital anomalies. Knowledge about using folic acid before and in the first trimester of pregnancy was highest among university-educated women and those working in professional occupations. Only 18.8% of women reported taking folic acid, and 8.8% had used it before conception. Awareness campaigns are suggested to improve knowledge about folic acid among women in the childbearing period in Egypt.