Prenatal factors in the development of chronic lung disease

Mutaba'ah-Mother and Child Health Study: protocol for a prospective cohort study investigating the maternal and early life determinants of infant, child, adolescent and maternal health in the United Arab Emirates

INTRODUCTION

Early life exposures, particularly environmental and parental lifestyle factors, have a major influence on children's health and development. Due to increasing interest in the early life developmental origins of diseases, many birth cohorts have been established. These studies constitute a repository of data which researchers use over many years to investigate emerging research questions. However, no such databank or cohort study is available in the United Arab Emirates (UAE). This project aims to establish a prospective mother and child cohort study in Al Ain (Abu Dhabi, UAE) to investigate the maternal and early life determinants of infant, child, adolescent and maternal health of the Emirati population.

METHODS AND ANALYSIS

During the period 2017-2021, this study aims to recruit 10 000 pregnancies at approximately 12 weeks of gestation from hospitals and clinics in Al Ain city. For each mother/newborn pair, an initial dataset will be collected including anthropometric, physiological and biochemical measurements, medical interventions, circumstances of pregnancy, delivery details and neonatal and perinatal growth and health using a combination of questionnaires, interviews and medical record extractions. Baseline data will act as the starting point from which the children will be followed up and re-surveyed at intervals throughout their life course until the age of 16 years, to explore how familial, socioeconomic and lifestyle factors interact with genetic and environmental factors to influence health outcomes and achievements later in life.

ETHICS AND DISSEMINATION

Ethical approval has been granted by the United Arab Emirates University Human Research Ethics Committee and the ethical committees of the participating institutions. Results will be widely disseminated via peer-reviewed manuscripts, conference presentations, media outlets and reports to relevant authorities.

Maternal and birth cohort studies in the Gulf Cooperation Council countries: protocol for a systematic review and narrative evaluation

INTRODUCTION

Cohort studies have revealed that genetic, socioeconomic, communicable and non-communicable diseases, and environmental exposures during pregnancy may influence the mother and her pregnancy, birth delivery and her offspring. Numerous studies have been conducted in the Gulf Cooperation Council (GCC) countries to examine maternal and birth health. The objectives of this protocol for a systematic review are to systematically review and characterise the exposures and outcomes that have been examined in the mother and birth cohort studies in the GCC region, and to summarise the strength of association between key maternal exposures during pregnancy (ie, body mass index) and different health-related outcomes (ie, mode of birth delivery). The review will then synthesise and characterise the consequent health implications and will serve as a platform to help identify areas that are overlooked, point out limitations of studies and provide recommendations for future cohort studies.

METHODS AND ANALYSIS

Medline, Embase, Cochrane Library and Web of Science electronic databases will be comprehensively searched. Two reviewers will independently screen each study for eligibility, and where discrepancies arise they will be discussed and resolved; otherwise a third reviewer will be consulted. The two reviewers will also independently extract data into a predefined Excel spreadsheet. The included studies will be categorised on the basis of whether the participant is a mother, infant or mother-infant dyad. Outcome variables will be divided along two distinctions: mother or infant. Exposure variables will be divided into six domains: psychosocial, biological, environmental, medical/medical services, maternal/reproductive and perinatal/child. Studies are expected to be of heterogeneous nature; therefore, quantitative syntheses might be limited.

ETHICS AND DISSEMINATION

There is no primary data collection; therefore, ethical review is not necessary. The findings of this review will be disseminated in a peer-reviewed journal and presented at relevant conferences.

PROSPERO REGISTRATION NUMBER

CRD42017068910.

Maternal high-fat hypercaloric diet during pregnancy results in persistent metabolic and respiratory abnormalities in offspring

BACKGROUND

We have shown in a previous population-based study significant correlation between childhood asthma and early abnormalities of lipid and glucose metabolism. This study's specific aim was to determine whether maternal nutrition in pregnancy affects postnatal metabolic and respiratory outcomes in the offspring.

METHODS

On gestation day 1, dams were switched from standard chow to either high-fat hypercaloric diet or control diet. Terminal experiments were performed on newborn and weanling offspring of dams fed the study diet during gestation and lactation, and on adult offspring maintained on the same diet as their mother.

RESULTS

Pups born from high-fat hypercaloric diet (HFD) dams developed metabolic abnormalities persistent throughout development. Cytokine expression analysis of lung tissues from newborns born to HFD dams revealed a strong proinflammatory pattern. Gene expression of neurotrophic factors and receptors was upregulated in lungs of weanlings born to HFD dams, and this was associated to higher respiratory system resistance and lower compliance at baseline, as well as hyperreactivity to aerosolized methacholine. Furthermore, HFD dams delivered pups prone to develop more severe disease after respiratory syncytial virus (RSV) infection.

CONCLUSION

Maternal nutrition in pregnancy is a critical determinant of airway inflammation and hyperreactivity in offspring and also increases risk for bronchiolitis independent from prepregnancy nutrition.

Amniotic fluid derived mesenchymal stromal cells augment fetal lung growth in a nitrofen explant model

PURPOSE

Recent experimental work suggests the therapeutic role of mesenchymal stromal cells (MSCs) during lung morphogenesis. The purpose of this study was to investigate the potential paracrine effects of amniotic fluid-derived MSCs (AF-MSCs) on fetal lung growth in a nitrofen explant model.

METHODS

Pregnant Sprague-Dawley dams were gavage fed nitrofen on gestational day 9.5 (E9.5). E14.5 lung explants were subsequently harvested and cultured ex vivo for three days on filter membranes in conditioned media from rat AF-MSCs isolated from control (AF-Ctr) or nitrofen-exposed (AF-Nitro) dams. The lungs were analyzed morphometrically and by quantitative gene expression.

RESULTS

Although there were no significant differences in total lung surface area among hypoplastic lungs, there were significant increases in terminal budding among E14.5+3 nitrofen explants exposed to AF-Ctr compared to explants exposed to medium alone (58.8±8.4 vs. 39.0±10.0 terminal buds, respectively; p<0.05). In contrast, lungs cultured in AF-Nitro medium failed to augment terminal budding. Nitrofen explants exposed to AF-Ctr showed significant upregulation of surfactant protein C to levels observed in normal fetal lungs.

CONCLUSIONS

AF-MSCs can augment branching morphogenesis and lung epithelial maturation in a fetal explant model of pulmonary hypoplasia. Cell therapy using donor-derived AF-MSCs may represent a novel strategy for the treatment of fetal congenital diaphragmatic hernia.

Fetal growth restriction is worse than extreme prematurity for the developing lung

BACKGROUND

Perinatal lung growth is highly vulnerable to inflammation and intrauterine growth restriction (IUGR), two major risk factors for chronic lung disease (CLD) in preterm neonates. However, the balance between extremely low gestational age (ELGA) and IUGR in very preterm infants as risk factors for CLD and co-morbidities remains poorly explored.

OBJECTIVES

This single-center study aims to compare neonatal morbidity (including CLD) and mortality among ELGA infants with normal birth weight (ELGA-AGA), very preterm infants with IUGR <3rd percentile (VLGA-IUGR) and very preterm infants with a birth weight appropriate for gestational age (VLGA-AGA), matched with VLGA-IUGR infants.

METHODS

Selected characteristics of the perinatal and neonatal periods were recorded and retrospectively compared among the three groups. Infants with major congenital anomalies were excluded. The diagnosis of CLD was based on whether the infant was receiving supplemental oxygen and/or non-invasive ventilation at a postmenstrual age of 36 weeks.

RESULTS

We found that, despite a median difference of 3 weeks in gestational age at birth between VLGA-IUGR and ELGA-AGA infants, neonatal mortality was 35% higher in neonates who had experienced fetal growth restriction, and that VLGA- IUGR was five times more predictive of CLD than was ELGA-AGA. These differences persisted after adjustment for confounding factors such as antenatal steroids, gender and respiratory distress syndrome.

CONCLUSIONS

This study reports that VLGA-IUGR infants are at higher risk of neonatal mortality and CLD than both ELGA-AGA and VLGA-AGA infants.

Determination of selenium in serum samples of preterm newborn infants with bronchopulmonary dysplasia using a validated hydride generation system

Bronchopulmonary dysplasia (BPD), also known as chronic lung disease, is one of the most challenging complications in premature newborn infants. Selenium plays a role in antioxidant system by protecting cell membranes and neutralizing the deleterious effects of free radicals. The aim of this study was to determine the relationship between selenium concentration and incidence of bronchopulmonary dysplasia using a validated analytical method. Umbilical cord blood and blood samples 30 days after the birth were collected from 38 preterm newborn infants with gestation age of 32 weeks or less, and the separated serums were kept at -70°C until analysis time. Selenium concentration of serum was determined using an atomic absorption spectrophotometer. The method was validated on the basis of standard validation techniques. The analytical method was linear in the range of 1 to 500 μg/L with the limit of detection of 0.4 μg/L. Samples were collected from 38 infants whose gestation age was 32 weeks or less. The blood samples were collected from the umbilical cord blood at birth in 19 cases. In 25 cases, blood samples were collected 1 month after birth. Of the 15 patients diagnosed with BPD, 10 were boys (p = 0.02). The mean serum selenium concentration was not different at birth between patients with and without BPD, but it was significantly lower at 30 days after birth in patients with BPD (38.5 ± 14.1vs. 45.4 ± 18.7 μg/L, p = 0.02). Preterm newborn infants with BPD had lower serum selenium concentrations 1 month after birth.

Protective Effects of Nigella sativa Oil in Hyperoxia-Induced Lung Injury

BACKGROUND

Oxygen-induced lung injury is believed to lead to the development of bronchopulmonary dysplasia in premature infants. We have evaluated the beneficial effects of Nigella sativa oil (NSO) on rats with hyperoxia-induced lung injury.

METHODS

Thirty newborn Sprague-Dawley rats were randomly divided into 3 groups as hyperoxia (95% O(2)), hyperoxia+NSO and control (21% O(2)). Pups in the hyperoxia+NSO group were administered intraperitoneal NSO at a dose of 4ml/kg daily during the study period. Histopathologic, immunochemical, and biochemical evaluations (superoxide dismutase [SOD], glutathione peroxidase [GSH-Px], malonaldehyde [MDA] and myeloperoxidase [MPO]) were performed.

RESULTS

In the histopathologic and immunochemical evaluation, severity of lung damage was significantly lower in the hyperoxia+NOS group (P<.05). Tissue GSH-Px and SOD levels were significantly preserved, and MDA, MPO levels were significantly lower in the hyperoxia+NSO group (P<.05).

CONCLUSION

NSO significantly reduced the severity of lung damage due to hyperoxia.

The expression of HoxB5 and its role in neonatal rats with chronic lung disease

The purpose of this investigation is to research the expression and effect of HoxB5 during pulmonary injury and to investigate the repairing ability of alveolar epithelial cells in such processes. Eighty neonatal rats were randomly divided into two groups: a group of high concentration of oxygen and the control group. The high oxygen group would inhale 85 to 90% oxygen and the control group would inhale air. The lung tissues on the 1(st), 3(rd), 7(th), 14(th), and 21(st) days would be obtained, in which immunohistochemical assay and Reverse Transcription Polymerase Chain Reaction (RT-PCR) would be performed to test the expressions of proteins and mRNAs of surfactant protein C (SPC) and AQP5. For expression of HoxB5 protein and its mRNA, immunohistochemical assay, western blot, in-situ hybridization, and RT-PCR would be run. The expression of SPC in the group of high concentration of oxygen was significantly reduced on day 3. Its expressions on day 14 and day 21 were significantly higher than those of the control group (p < 0.05). The expression of AQP5 in the group of high concentration of oxygen progressively decreased and such difference with the control group was significant (p < 0.05). The four experimental methods all showed the expression of HoxB5 in the group with high concentration of oxygen gradually decreased since day 7 (p < 0.05). High concentration of oxygen is damaging to alveolar epithelial cells. Although the number of type II alveolar epithelial cells (AECII) increases, its ability to differentiate and transform is significantly reduced and the reduced expression level of HoxB5 is possibly the reason for AECII to lose differentiation function to AECI.

Total antioxidant capacity and total oxidant status after surfactant treatment in preterm infants with respiratory distress syndrome

BACKGROUND

Oxidative damage is important in the pathogenesis of respiratory distress syndrome (RDS). However, data on the effect of surfactant therapy on oxidative stress in vivo are limited. We aimed to evaluate the oxidant/antioxidant status in preterm infants with RDS via measurement of total antioxidant capacity (TAC) and total oxidant status (TOS), to determine the effect of surfactant on oxidant/antioxidant balance and to assess the association between TAC, TOS and clinical outcomes of the patients.

METHODS

Sixty-nine infants with RDS were included. Blood samples for determining TAC and TOS were collected before and 48 h after surfactant treatment. TAC and TOS levels were analysed in serum. Patients were followed up until discharge or death.

RESULTS

Post-surfactant TAC levels were significantly higher than pre-surfactant TAC levels (P = 0.029). TAC/TOS ratio significantly increased after surfactant treatment (P = 0.018). Infants <28 weeks of gestational age had lower levels of baseline TAC than those ≥28 weeks of gestational age (P = 0.020), whereas TOS levels were similar. Baseline TAC/TOS ratio was lower in infants who died in the study period than those who survived (P = 0.023). After controlling gestational age, baseline TAC levels were significantly and inversely correlated with the duration of total respiratory support (r = -0.343; P = 0.009) and hospitalization (r = -0.341; P = 0.009). TAC or TOS levels were not associated with the development of bronchopulmonary dysplasia or other complications as determined during the investigation period.

CONCLUSIONS

Oxidant-antioxidant balance shifts in favour of the antioxidant system after surfactant treatment. Lower TAC/TOS ratio in preterm infants may be associated with increased mortality.