Update on Vitamin E and Its Potential Role in Preventing or Treating Bronchopulmonary Dysplasia

Temporal Dynamics of Oxidative Stress and Inflammation in Bronchopulmonary Dysplasia

Bronchopulmonary dysplasia (BPD) is the most common lung complication of prematurity. Despite extensive research, our understanding of its pathophysiology remains limited, as reflected by the stable prevalence of BPD. Prematurity is the primary risk factor for BPD, with oxidative stress (OS) and inflammation playing significant roles and being closely linked to premature birth. Understanding the interplay and temporal relationship between OS and inflammation is crucial for developing new treatments for BPD. Animal studies suggest that OS and inflammation can exacerbate each other. Clinical trials focusing solely on antioxidants or anti-inflammatory therapies have been unsuccessful. In contrast, vitamin A and caffeine, with antioxidant and anti-inflammatory properties, have shown some efficacy, reducing BPD by about 10%. However, more than one-third of very preterm infants still suffer from BPD. New therapeutic agents are needed. A novel tripeptide, N-acetyl-lysyltyrosylcysteine amide (KYC), is a reversible myeloperoxidase inhibitor and a systems pharmacology agent. It reduces BPD severity by inhibiting MPO, enhancing antioxidative proteins, and alleviating endoplasmic reticulum stress and cellular senescence in a hyperoxia rat model. KYC represents a promising new approach to BPD treatment.

Mechanisms for initiation of food allergy by skin pre-disposed to atopic dermatitis

Food allergy can be life-threatening and often develops early in life. In infants and children, loss-of-function mutations in skin barrier genes associate with food allergy. In a mouse model with skin barrier mutations (Flakey Tail, FT+/- mice), topical epicutaneous sensitization to a food allergen peanut extract (PNE), an environmental allergen Alternaria alternata (Alt) and a detergent induce food allergy and then an oral PNE-challenge induces anaphylaxis. Exposures to these allergens and detergents can occur for infants and children in a household setting. From the clinical and preclinical studies of neonates and children with skin barrier mutations, early oral exposure to allergenic foods before skin sensitization may induce tolerance to food allergens and thus protect against development of food allergy. In the FT+/- mice, oral food allergen prior to skin sensitization induce tolerance to food allergens. However, when the skin of FT+/- pups are exposed to a ubiquitous environmental allergen at the time of oral consumption of food allergens, this blocks the induction of tolerance to the food allergen and the mice can then be skin sensitized with the food allergen. The development of food allergy in neonatal FT+/- mice is mediated by altered skin responses to allergens with increases in skin expression of interleukin 33, oncostatin M and amphiregulin. The development of neonate food allergy is enhanced when born to an allergic mother, but it is inhibited by maternal supplementation with α-tocopherol. Moreover, preclinical studies suggest that food allergen skin sensitization can occur before manifestation of clinical features of atopic dermatitis. Thus, these parameters may impact design of clinical studies for food allergy, when stratifying individuals by loss of skin barrier function or maternal atopy before offspring development of atopic dermatitis.

Association of prenatal vitamin E levels with child asthma and wheeze

BACKGROUND

We investigated the individual and interaction effects of maternal plasma 𝛂- and ϒ-tocopherol levels (vitamin E isomers) on child asthma and wheeze at age 8-9.

METHODS

Mother-child dyads were enrolled between 2006 and 2011 into the Conditions Affecting Neurocognitive Development and Learning in Early Childhood (CANDLE) prenatal cohort. Maternal second-trimester samples were analyzed for tocopherol and lipid concentrations. We assessed child asthma/wheeze using the International Study of Asthma and Allergies in Childhood (ISAAC) and other self-reported Ent wheeze. In multivariable logistic regression analyses, we assessed associations between vitamin E isomers and child asthma/wheeze outcomes (n = 847 mother-child dyads) and tested for prespecified interaction terms.

RESULTS

Median cholesterol-corrected tocopherol levels (interquartile range (IQR)) were 5.0 (4.3-5.7) and 0.8 (0.7-0.9) (umol/mmol) for 𝛂- and ϒ-tocopherol, respectively. Associations between 𝛂-tocopherol and asthma outcome variables were inverse but not statistically significant. In contrast, for ϒ-tocopherol, associations were in the positive direction, but also nonsignificant. Interactions analysis between tocopherols did not reach statistical significance for any outcome. Among children of women with a history of asthma, the likelihood of ever asthma in the child appears to be decreasing with increasing maternal 𝛂-tocopherol levels, whereas this trend was not observed among those without a history of asthma (p-interaction = .05).

CONCLUSION

We observed no associations for prenatal 𝛂- or ϒ-tocopherol concentrations with child asthma/wheeze. We detected some evidence of effect modification by maternal asthma history in associations between 𝛂-tocopherol and child asthma.

Recurrent respiratory tract infections in children might be associated with vitamin A status: a case-control study

Background

Recurrent respiratory tract infections (RRTIs) are common in children and its development might be associated with vitamin A deficiency according to recent research. The aim of this study was to understand the relation between vitamin A status and RRTIs in children, and the relation between dietary intake of vitamin A and RRTIs.

Methods

2,592 children aged 0.5-14 years from Heilongjiang province of China participated in the survey. The RRTI group consisted of 1,039 children with RRTIs, while 1,553 healthy children were included in the control group. The levels of serum vitamin A were determined by high performance liquid chromatography (HPLC); dietary information was collected with the Food Frequency Questionnaire (FFQ).

Results

Serum vitamin A concentration in the RRTI group was significantly lower than that in the control group (0.27 ± 0.09 mg/L vs. 0.29 ± 0.09 mg/L) (P < 0.01). The levels of vitamin A was obviously associated with the occurrence of RRTIs. The odds ratios (ORs) for vitamin A insufficiency and deficiency were 1.32 (95% CI: 1.09-1.60) and 1.95 (95% CI: 1.50-2.55) respectively; whereas 1.48 (95% CI: 1.13-1.94) and 6.51 (95% CI: 4.18-10.14) respectively, in children with current respiratory tract infection (RTI) symptoms. Even an insufficient intake of animal liver was associated with lower RRTIs [OR: 0.45 (95% CI: 0.38-0.53)], while only an excessive intake of meat had the same effect [OR: 0.85 (95% CI: 0.68-1.06)].

Conclusions

Low serum vitamin A concentration was associated with high incidence of RRTIs in children in northeast China; low serum vitamin A concentrations and the current RTI symptoms were associated with the development of RRTIs; and low intakes of vitamin A-rich foods were also associated with the development of RRTIs.

Nutritional Needs of the Infant with Bronchopulmonary Dysplasia

Growth failure is a common problem in infants with established bronchopulmonary dysplasia (BPD). Suboptimal growth for infants with BPD is associated with unfavorable respiratory and neurodevelopmental outcomes; however, high-quality evidence to support best nutritional practices are limited for this vulnerable patient population. Consequently, there exists a wide variation in the provision of nutritional care and monitoring of growth for infants with BPD. Other neonatal populations at risk for growth failure, such as infants with congenital heart disease, have demonstrated improved growth outcomes with the creation and compliance of clinical protocols to guide nutritional management. Developing clinical protocols to guide nutritional management for infants with BPD may similarly improve long-term outcomes. Given the absence of high-quality trials to guide nutritional practice in infants with BPD, the best available evidence of systematic reviews and clinical recommendations can be applied to optimize growth and decrease variation in the care of these infants.

Select micronutrients for the preterm neonate

If premature neonates are not provided with adequate nutrition, they will quickly become deficient because of increased requirements and a lack of nutrient stores to achieve adequate growth. The provision of many of the recommended micronutrients for pediatric and adult patients is challenging in premature neonates because of the limited data surrounding the true needs of premature neonates and the difficulty in assessing adequate serum levels of these nutrients in this patient population. Parenteral and enteral nutrition shortages further complicate providing adequate micronutrients to premature neonates. This review will discuss select micronutrients and their importance to the preterm neonate, with special emphasis on micronutrients with limited evidence and more challenging supplementation and repletion strategies.

Evaluation of Vitamin E Isoforms in Placental Tissue and Their Relationship with Maternal Dietary Intake and Plasma Concentrations in Mother-Infant Dyads

α-tocopherol is a vitamin E isoform with potent antioxidant activity, while the γ-tocopherol isoform of vitamin E exerts more pro-inflammatory effects. In maternal-fetal environments, increased plasma α-tocopherol concentrations are associated with positive birth outcomes, while higher γ-tocopherol concentrations are linked with negative pregnancy outcomes. However, little is known about tocopherol concentrations in placental tissue and their role in modulating placental oxidative stress, a process that is implicated in many complications of pregnancy. The objectives of this research are to evaluate the concentrations of α- and γ-tocopherol in placental tissue and assess relationships with maternal and umbilical cord plasma concentrations. A total of 82 mother-infant dyads were enrolled at the time of delivery, and maternal and umbilical cord blood samples and placenta samples were collected. α- and γ-tocopherol concentrations in these samples were analyzed by high-performance liquid chromatography (HPLC). γ-tocopherol concentrations demonstrated significant, positive correlations among all sample types (p-values < 0.001). Placental tissue had a significantly lower ratio of α:γ-tocopherol concentrations when compared to maternal plasma and umbilical cord plasma (2.9 vs. 9.9 vs. 13.2, respectively; p < 0.001). Additional research should explore possible mechanisms for tocopherol storage and transfer in placental tissue and assess relationships between placental tocopherol concentrations and measures of maternal-fetal oxidative stress and clinical outcomes of pregnancy.

Dysbiotic lung microbial communities of neonates from allergic mothers confer neonate responsiveness to suboptimal allergen

In humans and animals, offspring of allergic mothers have increased responsiveness to allergens. This is blocked in mice by maternal supplementation with α-tocopherol (αT). Also, adults and children with allergic asthma have airway microbiome dysbiosis with increased Proteobacteria and may have decreased Bacteroidota. It is not known whether αT alters neonate development of lung microbiome dysbiosis or whether neonate lung dysbiosis modifies development of allergy. To address this, the bronchoalveolar lavage was analyzed by 16S rRNA gene analysis (bacterial microbiome) from pups of allergic and non-allergic mothers with a basal diet or αT-supplemented diet. Before and after allergen challenge, pups of allergic mothers had dysbiosis in lung microbial composition with increased Proteobacteria and decreased Bacteroidota and this was blocked by αT supplementation. We determined whether intratracheal transfer of pup lung dysbiotic microbial communities modifies the development of allergy in recipient pups early in life. Interestingly, transfer of dysbiotic lung microbial communities from neonates of allergic mothers to neonates of non-allergic mothers was sufficient to confer responsiveness to allergen in the recipient pups. In contrast, neonates of allergic mothers were not protected from development of allergy by transfer of donor lung microbial communities from either neonates of non-allergic mothers or neonates of αT-supplemented allergic mothers. These data suggest that the dysbiotic lung microbiota is dominant and sufficient for enhanced neonate responsiveness to allergen. Importantly, infants within the INHANCE cohort with an anti-inflammatory profile of tocopherol isoforms had an altered microbiome composition compared to infants with a pro-inflammatory profile of tocopherol isoforms. These data may inform design of future studies for approaches in the prevention or intervention in asthma and allergic disease early in life.

Heme induces intestinal epithelial cell ferroptosis via mitochondrial dysfunction in transfusion-associated necrotizing enterocolitis

Transfusion-associated necrotising enterocolitis (TANEC) is a life-threatening disease with a poor prognosis in preterm infants. This study explored whether and how heme induces ferroptosis in TANEC gut injury. A TANEC mouse model and a cell culture system for heme and Caco-2 cells were established. Ferroptosis was assessed by measuring iron and malondialdehyde (MDA) levels and mitochondrial morphology in intestinal tissues and Caco-2 cells. Mitochondrial dysfunction was evaluated by measuring mitochondrial reactive oxygen species (ROS) production and membrane potential using JC-1. The intestinal injury grade was higher in the anemia-transfusion group than in the control group (p < .0001). Higher intestinal iron concentration (p < .0001), elevated levels of lipid peroxidation MDA (p = .0021), and ferroptotic mitochondrial morphological changes were found in mice of the anemia-transfusion group; specific ferroptosis inhibitor could alleviate anemia-transfusion gut injury, suggesting that ferroptosis play a role in the TANEC gut injury. Next, we explored whether heme released by hemolysis of erythrocytes induces ferroptosis in intestinal epithelial cells in vitro. The viability of Caco-2 cells significantly decreased after heme treatment (p < .0001). Iron accumulation, MDA elevated levels, and mitochondrial dysfunction also existed in the co-culture system, which ferroptosis inhibitors could reduce. In summary, ferroptosis was discovered in TANEC, and heme could induce ferroptosis in intestinal epithelial cells via mitochondrial dysfunction. Heme-inducing ferroptosis may be a possible mechanism and therapeutic target for TANEC.

Pathogenesis of Bronchopulmonary Dysplasia: Role of Oxidative Stress from 'Omics' Studies

Bronchopulmonary dysplasia (BPD) remains the most common respiratory complication of prematurity as younger and smaller infants are surviving beyond the immediate neonatal period. The recognition that oxidative stress (OS) plays a key role in BPD pathogenesis has been widely accepted since at least the 1980s. In this article, we examine the interplay between OS and genetic regulation and review 'omics' data related to OS in BPD. Data from animal models (largely models of hyperoxic lung injury) and from human studies are presented. Epigenetic and transcriptomic analyses have demonstrated several genes related to OS to be differentially expressed in murine models that mimic BPD as well as in premature infants at risk of BPD development and infants with established lung disease. Alterations in the genetic regulation of antioxidant enzymes is a common theme in these studies. Data from metabolomics and proteomics have also demonstrated the potential involvement of OS-related pathways in BPD. A limitation of many studies includes the difficulty of obtaining timely and appropriate samples from human patients. Additional 'omics' studies could further our understanding of the role of OS in BPD pathogenesis, which may prove beneficial for prevention and timely diagnosis, and aid in the development of targeted therapies.

Role of Vitamin E in Neonatal Neuroprotection: A Comprehensive Narrative Review

Vitamin E (Vit E) is an essential lipophilic antioxidant and anti-inflammatory agent that has potential as a neuroprotectant in newborn infants with brain injury. Vit E has shown promise in many in vitro studies, but success in translation to in vivo animal studies and the clinical setting has been mixed, with concern of adverse effects at high intravenous doses in preterm infants. However, a recent rise in knowledge of the beneficial effects of fat emulsions containing higher levels of Vit E, along with associated improved outcomes in some neonatal co-morbidities, has led many to reconsider Vit E administration as a potential therapeutic modality to improve neurological outcomes in the setting of neonatal brain injury. This narrative review discusses Vit E's structure, mechanism(s) of action, evidence in animal models, and association with health outcomes in neonates, including both dietary and supplemental Vit E and their bioavailability and pharmacokinetics as it relates to the brain. Lastly, long-term neurodevelopmental outcomes along with gaps in current knowledge are critiqued, which to date suggests that additional translational studies in larger animal models and assessment of safety profiles of different routes and doses of administration should be explored prior to large clinical trials. Importantly, a greater understanding of the brain region(s) and cell type(s) affected by Vit E may help to target the use of Vit E as a beneficial neuroprotective agent to specific populations or types of injury seen in newborns.

Antioxidants: Role the in prevention and treatment of bronchopulmonary dysplasia

Bronchopulmonary dysplasia (BPD) is one of the major causes of chronic respiratory diseases among infants. Both pharmacological and nonpharmacological approaches have been proposed for its management. Since oxidative stress is known to play a pivotal role in the pathogenesis of BPD, it is reasonable to consider the potential of antioxidant strategies in the prevention and treatment of this condition. Indeed, antioxidants can prevent or inhibit substrate oxidation. Some studies have evaluated the efficacy of the exogenous administration of vitamins and micronutrients in reducing the propagation of free radicals through their scavenging capacity. Nonetheless, encouraging preclinical results did not translate into effective preventive and/or therapeutic interventions. This narrative review evaluates the current evidence about the antioxidants that are potentially useful for preventing and treating BPD and explores the most relevant issues affecting their implementation in clinical practice, as well as their associated evidence gaps and research limitations.

Vitamin E and preterm infants

In evaluating vitamin E (VE) nutritional status of preterm infants, it is essential that any data should be compared with those of healthy term infants, and never with those of adults. Moreover, it should be evaluated in terms of gestational age (GA), not birth weight (BW), because placental transfer of most nutrients from mother to fetus is dependent on GA, not BW. Judging from the limited data during the last 75 years, there was no significant correlation between GA and VE concentrations in circulation or in the red blood cells (RBCs), leukocytes, and buccal mucosal cells. In addition, the oxidizability of polyunsaturated fatty acids (PUFAs) in plasma or RBCs, as targets for protection by VE chain-breaking ability, was lower in preterm infants. However, because of the minimal information available about hepatic VE levels, which is considered a key determinant of whole body VE status, the decision on whether VE status of preterm infants is comparable with that of term infants should be postponed. Clinical trials of VE supplementation in preterm infants were repeatedly undertaken to investigate whether VE reduces severity or inhibits development of several diseases specific to preterm infants, namely retinopathy of prematurity (ROP), bronchopulmonary dysplasia (BPD), and germinal matrix hemorrhage - intraventricular hemorrhage (GMH-IVH). Most of these trials resulted in a misfire, with a few exceptions for IVH prevention. However, almost all these studies were performed from 1980s to early 1990s, in the pre-surfactant era, and the study populations were composed of mid-preterm infants with GAs of approximately 30 weeks (wks). There is considerable difference in 'preterm infants' between the pre- and post-surfactant eras; modern neonatal medicine mainly treats preterm infants of 28 wks GA or less. Therefore, these results are difficult to apply in modern neonatal care. Before considering new trials of VE supplementation, we should fully understand modern neonatal medicine, especially the recent method of oxygen supplementation. Additionally, a deeper understanding of recent progress in pathophysiology and therapies for possible target diseases is necessary to decide whether VE administration is still worth re-challenging in modern neonatal intensive care units (NICUs). In this review, we present recent concepts and therapeutic trends in ROP, BPD, and GMH-IVH for those unfamiliar with neonatal medicine. Numerous studies have reported the possible involvement of reactive oxygen species (ROS)-induced damage in relation to supplemental oxygen use, inflammation, and immature antioxidant defense in the development of both BPD and ROP. Various antioxidants effectively prevented the exacerbation of BPD and ROP in animal models. In the future, VE should be re-attempted as a complementary factor in combination with various therapies for BPD, ROP, and GMH-IVH. Because VE is a natural and safe supplement, we are certain that it will attract attention again in preterm medicine.

Asthma, allergy and vitamin E: Current and future perspectives

Asthma and allergic disease result from interactions of environmental exposures and genetics. Vitamin E is one environmental factor that can modify development of allergy early in life and modify responses to allergen after allergen sensitization. Seemingly varied outcomes from vitamin E are consistent with the differential functions of the isoforms of vitamin E. Mechanistic studies demonstrate that the vitamin E isoforms α-tocopherol and γ-tocopherol have opposite functions in regulation of allergic inflammation and development of allergic disease, with α-tocopherol having anti-inflammatory functions and γ-tocopherol having pro-inflammatory functions in allergy and asthma. Moreover, global differences in prevalence of asthma by country may be a result, at least in part, of differences in consumption of these two isoforms of tocopherols. It is critical in clinical and animal studies that measurements of the isoforms of tocopherols be determined in vehicles for the treatments, and in the plasma and/or tissues before and after intervention. As allergic inflammation is modifiable by tocopherol isoforms, differential regulation by tocopherol isoforms provide a foundation for development of interventions to improve lung function in disease and raise the possibility of early life dietary interventions to limit the development of lung disease.

Supplemental Oxygen in the Newborn: Historical Perspective and Current Trends

Oxygen is the final electron acceptor in aerobic respiration, and a lack of oxygen can result in bioenergetic failure and cell death. Thus, administration of supplemental concentrations of oxygen to overcome barriers to tissue oxygen delivery (e.g., heart failure, lung disease, ischemia), can rescue dying cells where cellular oxygen content is low. However, the balance of oxygen delivery and oxygen consumption relies on tightly controlled oxygen gradients and compartmentalized redox potential. While therapeutic oxygen delivery can be life-saving, it can disrupt growth and development, impair bioenergetic function, and induce inflammation. Newborns, and premature newborns especially, have features that confer particular susceptibility to hyperoxic injury due to oxidative stress. In this review, we will describe the unique features of newborn redox physiology and antioxidant defenses, the history of therapeutic oxygen use in this population and its role in disease, and clinical trends in the use of therapeutic oxygen and mitigation of neonatal oxidative injury.

Expanding role of vitamin E in protection against metabolic dysregulation: Insights gained from model systems, especially the developing nervous system of zebrafish embryos

This review discusses why the embryo requires vitamin E (VitE) and shows that its lack causes metabolic dysregulation and impacts morphological changes at very early stages in development, which occur prior to when a woman knows she is pregnant. VitE halts the chain reactions of lipid peroxidation (LPO). Metabolomic analyses indicate that thiols become depleted in E- embryos because LPO generates products that require compensation using limited amino acids and methyl donors that are also developmentally relevant. Thus, VitE protects metabolic networks and the integrated gene expression networks that control development. VitE is critical especially for neurodevelopment, which is dependent on trafficking by the α-tocopherol transfer protein (TTPa). VitE-deficient (E-) zebrafish embryos initially appear normal, but by 12 and 24 h post-fertilization (hpf) E- embryos are developmentally abnormal with expression of pax2a and sox10 mis-localized in the midbrain-hindbrain boundary, neural crest cells and throughout the spinal neurons. These patterning defects indicate cells that are especially in need of VitE-protection. They precede obvious morphological abnormalities (cranial-facial malformation, pericardial edema, yolksac edema, skewed body-axis) and impaired behavioral responses to locomotor activity tests. The TTPA gene (ttpa) is expressed at the leading edges of the brain ventricle border. Ttpa knockdown using morpholinos is 100% lethal by 24 hpf, while E- embryo brains are often over- or under-inflated at 24 hpf. Further, E- embryos prior to 24 hpf have increased expression of genes involved in glycolysis and the pentose phosphate pathway, and decreased expression of genes involved in anabolic pathways and transcription. Combined data from both gene expression and the metabolome in E- embryos at 24 hpf suggest that the activity of the mechanistic Target of Rapamycin (mTOR) signaling pathway is decreased, which may impact both metabolism and neurodevelopment. Further evaluation of VitE deficiency in neurogenesis and its subsequent impact on learning and behavior is needed.

Oxygen Toxicity to the Immature Lung-Part II: The Unmet Clinical Need for Causal Therapy

Oxygen toxicity continues to be one of the inevitable injuries to the immature lung. Reactive oxygen species (ROS) production is the initial step leading to lung injury and, subsequently, the development of bronchopulmonary dysplasia (BPD). Today, BPD remains the most important disease burden following preterm delivery and results in life-long restrictions in lung function and further important health sequelae. Despite the tremendous progress in the pathomechanistic understanding derived from preclinical models, the clinical needs for preventive or curative therapies remain unmet. This review summarizes the clinical progress on guiding oxygen delivery to the preterm infant and elaborates future directions of research that need to take into account both hyperoxia and hypoxia as ROS sources and BPD drivers. Many strategies have been tested within clinical trials based on the mechanistic understanding of ROS actions, but most have failed to prove efficacy. The majority of these studies were tested in an era before the latest modes of non-invasive respiratory support and surfactant application were introduced or were not appropriately powered. A comprehensive re-evaluation of enzymatic, antioxidant, and anti-inflammatory therapies to prevent ROS injury is therefore indispensable. Strategies will only succeed if they are applied in a timely and vigorous manner and with the appropriate outcome measures.

Influences of environmental exposures on preterm lung disease

Introduction: Environmental factors play a critical role in the progression or resolution of chronic respiratory diseases. However, studies are limited on the impact of environmental risk factors on individuals born prematurely with lung disease after they leave the neonatal intensive care unit and are discharged into the home environment.Areas covered: In this review, we cover current knowledge of environmental exposures that impact outcomes of preterm respiratory disease, including air pollution, infections, and disparities. The limited data do suggest that certain exposures should be avoided and there are potential preventative strategies for other exposures. There is a need for additional research outside the neonatal intensive care unit that focuses on individual and community-level factors that affect long-term outcomes.Expert opinion: Preterm respiratory disease can impose a significant burden on infants, children, and young adults born prematurely, but may improve for many individuals over time. In this review, we outline the exposures that may potentially hasten, delay, or prevent resolution of lung injury in preterm children.

Neonatal Extracellular Superoxide Dismutase Knockout Mice Increase Total Superoxide Dismutase Activity and VEGF Expression after Chronic Hyperoxia

Bronchopulmonary dysplasia (BPD) is a common lung disease affecting premature infants that develops after exposure to supplemental oxygen and reactive oxygen intermediates. Extracellular superoxide dismutase (SOD3) is an enzyme that processes superoxide radicals and has been shown to facilitate vascular endothelial growth factor (VEGF) and nitric oxide (NO) signaling in vascular endothelium. We utilized a mouse model of neonatal hyperoxic lung injury and SOD3 knockout (KO) mice to evaluate its function during chronic hyperoxia exposure. Wild-type age-matched neonatal C57Bl/6 (WT) and SOD3^−/− (KO) mice were placed in normoxia (21% FiO₂, RA) or chronic hyperoxia (75% FiO₂, O₂) within 24 h of birth for 14 days continuously and then euthanized. Lungs were harvested for histologic evaluation, as well as comparison of antioxidant enzyme expression, SOD activity, VEGF expression, and portions of the NO signaling pathway. Surprisingly, KO-O₂ mice survived without additional alveolar simplification, microvascular remodeling, or nuclear oxidation when compared to WT-O₂ mice. KO-O₂ mice had increased total SOD activity and increased VEGF expression when compared to WT-O₂ mice. No genotype differences were noted in intracellular antioxidant enzyme expression or the NO signaling pathway. These results demonstrate that SOD3 KO mice can survive prolonged hyperoxia without exacerbation of alveolar or vascular phenotype.

The association of vitamin D and vitamin E levels at birth with bronchopulmonary dysplasia in preterm infants

BACKGROUND

Despite improvements made in neonatal care, bronchopulmonary dysplasia (BPD) is still the most common respiratory disease in preterm infants. The relationship between the blood contents of vitamin D/E in premature infants and BPD is still controversial.

METHODS

Preterm infants were recruited as the research subjects. On the basis of the inclusion and exclusion criteria, a total of 133 eligible cases were finally included. A total of 63 preterm infants with a clear diagnosis of BPD and 5 preterm infants who died before the diagnosis of BPD were in the case group, and 65 non-BPD preterm infants with equivalent baseline characteristics were in the control group. The BPD group included 38 cases in Grade Ⅰ, 18 cases in Grade Ⅱ, and 12 cases in Grade Ⅲ. The contents of vitamin D and E in the cord blood of different groups were detected by high-performance liquid chromatography and enzyme-linked immunosorbent assay. Correlation analysis adopted the Pearson correlation analytic method.

RESULTS

The serum vitamin D and E levels at birth were remarkably lower in the BPD group than the non-BPD group, both of which were also correlated with the severity of BPD. The vitamin D and E contents were negatively correlated with the oxygen support duration required for premature infants with BPD.

CONCLUSION

This study deepens our understanding of the field of BPD pathogenesis by demonstrating an association between vitamin D/E deficiency and BPD severity, suggesting that vitamin D and E might have potential clinical value in the prognosis and treatment of BPD.

The correlation between the vitamin A, D, and E levels and recurrent respiratory tract infections in children of different ages

OBJECTIVE

To investigate the correlation between the vitamin A, D, and E levels and recurrent respiratory tract infections (RRTIs) in children of different ages.

METHODS

A total of 150 RRTI patients were divided into three groups: the 0 to 2 year-old group, the 3-5 year-old group, and the 6-14 year-old group. Collectively, we refer to the three groups as the RRTI group. The serum vitamin A, D and E levels were measured in the three groups. Healthy children without RRTIs were recruited as a control group. The correlations between the changes in the vitamin A, D, and E levels and the RRTIs were analyzed.

RESULTS

The vitamin A, D, and E levels decreased significantly in the children with RRTIs, but only the vitamin A and D levels were negatively correlated with the incidence of RRTIs, while the vitamin E levels were not significantly correlated with the incidence of RRTIs. The follow-up results showed that the serum vitamin A, D, and E levels in the RRTI group were significantly increased after the treatment, and the WBC and CRP levels were remarkably reduced.

CONCLUSION

Monitoring the serum vitamin A and D levels helps determine the disease severity, and the supplementation of adequate vitamin A and D through diet or drugs is of great help in treating RRTIs.

In vivo respiratory toxicology of cooking oil fumes: Evidence, mechanisms and prevention

BACKGROUND

As cooking is an essential part of people's daily life, cooking oil fumes (COF) has been recognized as one of the major indoor air pollutant. Mounting epidemiological evidence has indicated that COF exposure is significantly associated with an increased risk of various health effects including lung cancer, but toxicological studies are very limited.

OBJECTIVES

We conduct a systematic study to provide toxicological evidence of COF exposure on the lungs, to examine the underlying toxicological mechanism, and to suggest intervention measures to mitigate this toxicity.

METHODS

A total 96 female rats were randomly divided into control groups, COF exposure groups (0.2, 2, 20 mg/kg) and vitamin E protection groups, receiving appropriate treatment for 30 days. First we measured airway hyperresponsiveness (AHR) followed by a lung histological analysis to investigate the toxicological effects of COF. We next analyzed the biomarkers of oxidative stress, inflammation, and apoptosis to examine the underlying toxicological mechanism, and finally we investigated the protective effects of vitamin E against the toxicity of COF.

RESULTS

AHR measurement indicated that the airway resistance increased with the COF dose and the lung histological assay showed narrowing of the airway lumen, which provided evidence of the toxicological effects of COF. The biomarkers of oxidative stress (ROS and MDA), pro-inflammation (TNF-α and IL-1β), and apoptosis (NF-κB and Caspase-3) were all significantly increased with COF dose. We observed that above toxicological effects and biomarker levels induced by COF were significantly ameliorated after administration of VE.

CONCLUSION

The toxicity of cooking oil fumes on the lungs is clear from the evidence and mechanism, and can be ameliorated by vitamin E. We suggested that oxidative stress may be primarily responsible for the observed cooking oil fumes-induced toxicity.

Nutrients and Microbiota in Lung Diseases of Prematurity: The Placenta-Gut-Lung Triangle

Cardiorespiratory function is not only the foremost determinant of life after premature birth, but also a major factor of long-term outcomes. However, the path from placental disconnection to nutritional autonomy is enduring and challenging for the preterm infant and, at each step, will have profound influences on respiratory physiology and disease. Fluid and energy intake, specific nutrients such as amino-acids, lipids and vitamins, and their ways of administration -parenteral or enteral-have direct implications on lung tissue composition and cellular functions, thus affect lung development and homeostasis and contributing to acute and chronic respiratory disorders. In addition, metabolomic signatures have recently emerged as biomarkers of bronchopulmonary dysplasia and other neonatal diseases, suggesting a profound implication of specific metabolites such as amino-acids, acylcarnitine and fatty acids in lung injury and repair, inflammation and immune modulation. Recent advances have highlighted the profound influence of the microbiome on many short- and long-term outcomes in the preterm infant. Lung and intestinal microbiomes are deeply intricated, and nutrition plays a prominent role in their establishment and regulation. There is an emerging evidence that human milk prevents bronchopulmonary dysplasia in premature infants, potentially through microbiome composition and/or inflammation modulation. Restoring antibiotic therapy-mediated microbiome disruption is another potentially beneficial action of human milk, which can be in part emulated by pre- and probiotics and supplements. This review will explore the many facets of the gut-lung axis and its pathophysiology in acute and chronic respiratory disorders of the prematurely born infant, and explore established and innovative nutritional approaches for prevention and treatment.

Recent advances in our understanding of the mechanisms of lung alveolarization and bronchopulmonary dysplasia

Bronchopulmonary dysplasia (BPD) is the most common cause of morbidity and mortality in preterm infants. A key histopathological feature of BPD is stunted late lung development, where the process of alveolarization-the generation of alveolar gas exchange units-is impeded, through mechanisms that remain largely unclear. As such, there is interest in the clarification both of the pathomechanisms at play in affected lungs, and the mechanisms of de novo alveoli generation in healthy, developing lungs. A better understanding of normal and pathological alveolarization might reveal opportunities for improved medical management of affected infants. Furthermore, disturbances to the alveolar architecture are a key histopathological feature of several adult chronic lung diseases, including emphysema and fibrosis, and it is envisaged that knowledge about the mechanisms of alveologenesis might facilitate regeneration of healthy lung parenchyma in affected patients. To this end, recent efforts have interrogated clinical data, developed new-and refined existing-in vivo and in vitro models of BPD, have applied new microscopic and radiographic approaches, and have developed advanced cell-culture approaches, including organoid generation. Advances have also been made in the development of other methodologies, including single-cell analysis, metabolomics, lipidomics, and proteomics, as well as the generation and use of complex mouse genetics tools. The objective of this review is to present advances made in our understanding of the mechanisms of lung alveolarization and BPD over the period 1 January 2017-30 June 2019, a period that spans the 50th anniversary of the original clinical description of BPD in preterm infants.

Comparative two time-point proteome analysis of the plasma from preterm infants with and without bronchopulmonary dysplasia

BACKGROUND

In this study, we aimed to analyze differences in plasma protein abundances between infants with and without bronchopulmonary dysplasia (BPD), to add new insights into a better understanding of the pathogenesis of this disease.

METHODS

Cord and peripheral blood of neonates (≤ 30 weeks gestational age) was drawn at birth and at the 36th postmenstrual week (36 PMA), respectively. Blood samples were retrospectively subdivided into BPD(+) and BPD(-) groups, according to the development of BPD.

RESULTS

Children with BPD were characterized by decreased afamin, gelsolin and carboxypeptidase N subunit 2 levels in cord blood, and decreased galectin-3 binding protein and hemoglobin subunit gamma-1 levels, as well as an increased serotransferrin abundance in plasma at the 36 PMA.

CONCLUSIONS

BPD development is associated with the plasma proteome changes in preterm infants, adding further evidence for the possible involvement of disturbances in vitamin E availability and impaired immunological processes in the progression of prematurity pulmonary complications. Moreover, it also points to the differences in proteins related to infection resistance and maintaining an adequate level of hematocrit in infants diagnosed with BPD.

Nutrition and Lung Growth

Experimental evidence from animal models and epidemiology studies has demonstrated that nutrition affects lung development and may have a lifelong impact on respiratory health. Chronic restriction of nutrients and/or oxygen during pregnancy causes structural changes in the airways and parenchyma that may result in abnormal lung function, which is tracked throughout life. Inadequate nutritional management in very premature infants hampers lung growth and may be a contributing factor in the pathogenesis of bronchopulmonary dysplasia. Recent evidence seems to indicate that infant and childhood malnutrition does not determine lung function impairment even in the presence of reduced lung size due to delayed body growth. This review will focus on the effects of malnutrition occurring at critical time periods such as pregnancy, early life, and childhood, on lung growth and long-term lung function.