Gestational vitamin D deficiency impairs fetal lung development through suppressing type II pneumocyte differentiation

Pharmacokinetic modeling of prenatal vitamin D exposure and the impact on offspring asthma and pulmonary function

Gestational 25-hydroxyvitamin D (25[OH]D) is important in fetal lung development and may influence offspring respiratory outcomes, making accurate exposure assessment essential to understand clinical associations. Therefore, we used the combined data from two large RCTs investigating prenatal vitamin D supplementation, which included early and late prenatal 25(OH)D measurements, to refine a population pharmacokinetic model of vitamin D-25(OH)D and estimate individual area under the curve (AUC) Z-scores. The primary outcome was physician-diagnosed offspring asthma/wheezing at ages 3 and 6 years, and lung function, as a secondary outcome, was evaluated by spirometry at the ages 6 and 8 years. In total, 1319 mother-child pairs were included. We found that clearance of 25(OH)D increased with gestational age and bodyweight, and decreased with higher baseline 25(OH)D levels. Prenatal 25(OH)D AUC Z-scores were negatively associated with asthma/wheezing at age 3 years (aOR = 0.75, 95 % CI = 0.64-0.88, p < 0.001) and 6 years (aOR = 0.83, 95 % CI = 0.72-0.95, p = 0.008). Longitudinal analysis of lung function from age 6-8 years showed that AUC Z-scores were positively associated with percent-predicted FEV1 (β = 1.21%, 95 % CI = 0.30-2.11; p = 0.009), FVC (β = 0.79 %, 95 % CI = 0.13-1.46; p = 0.021), FEV1/FVC ratio (β = 0.56 %, 95 % CI = 0.11-1.01; p = 0.015) and FEF25-75 % (β = 2.18 %, 95 % CI = 0.46-3.91; p = 0.009). These results together indicate an exposure-outcome relationship where higher gestational 25(OH)D exposure, estimated by AUC, is associated with reduced childhood asthma/recurrent wheeze and improved lung function.

Vitamin D beyond the blood: Tissue distribution of vitamin D metabolites after supplementation

Vitamin D3's role in mineral homeostasis through its endocrine function, associated with the main circulating metabolite 25-hydroxyvitamin D3, is well characterized. However, the increasing recognition of vitamin D3's paracrine and autocrine functions-such as cell growth, immune function, and hormone regulation-necessitates examining vitamin D3 levels across different tissues post-supplementation. Hence, this review explores the biodistribution of vitamin D3 in blood and key tissues following oral supplementation in humans and animal models, highlighting the biologically active metabolite, 1,25-dihydroxyvitamin D3, and the primary clearance metabolite, 24,25-dihydroxyvitamin D3. While our findings indicate significant progress in understanding how circulating metabolite levels respond to supplementation, comprehensive insight into their tissue concentrations remains limited. The gap is particularly significant during pregnancy, a period of drastically increased vitamin D3 needs and metabolic alterations, where data remains sparse. Within the examined dosage ranges, both human and animal studies indicate that vitamin D3 and its metabolites are retained in tissues selectively. Notably, vitamin D3 concentrations in tissues show greater variability in response to administered doses. In contrast, its metabolites maintain a more consistent concentration range, albeit different among tissues, reflecting their tighter regulatory mechanisms following supplementation. These observations suggest that serum 25-hydroxyvitamin D3 levels may not adequately reflect vitamin D3 and its metabolite concentrations in different tissues. Therefore, future research should aim to generate robust human data on the tissue distribution of vitamin D3 and its principal metabolites post-supplementation. Relating this data to clinically appropriate exposure metrics will enhance our understanding of vitamin D3's cellular effects and guide refinement of clinical trial methodologies.

The impact of maternal asthma on the fetal lung: Outcomes, mechanisms and interventions

Maternal asthma affects up to 17% of pregnancies and is associated with adverse infant, childhood, and adult respiratory outcomes, including increased risks of neonatal respiratory distress syndrome, childhood wheeze and asthma. In addition to genetics, these poor outcomes are likely due to the mediating influence of maternal asthma on the in-utero environment, altering fetal lung and immune development and predisposing the offspring to later lung disease. Maternal asthma may impair glucocorticoid signalling in the fetus, a process critical for lung maturation, and increase fetal exposure to proinflammatory cytokines. Therefore, interventions to control maternal asthma, increase glucocorticoid signalling in the fetal lung, or Vitamin A, C, and D supplementation to improve alveologenesis and surfactant production may be beneficial for later lung function. This review highlights potential mechanisms underlying maternal asthma and offspring respiratory morbidities and describes how pregnancy interventions can promote optimal fetal lung development in babies of asthmatic mothers.

Ameliorative mechanism of dietary vitamin d and magnesium on newborn's pulmonary toxicity induced by cadmium

Cadmium (Cd) exposure in mothers can cause respiratory issues in newborns, but the exact toxicity mechanisms are not fully understood. Vitamin D deficiency in Cd-exposed rats is associated with increased cadmium accumulation in tissues. Finding a cost-effective medication that is vital for the body while also reducing the effects of poisoning is crucial in treating poisonings. To investigate the mechanisms of Cd-induced lung toxicity, we examined the impact of prolonged Cd exposure in female rats before pregnancy on newborn lung health, focusing on sera TNF-α level, lung P53, Foxo1 mRNA, and lung VEGF, and BMP-4 protein level. A total of 50 rats were divided into control, Cd, Cd+Vitamin D, Cd+Mg, and Cd + Vitamin D+Mg groups. Cd exposure resulted in higher serum TNF-α levels and a significant rise in P53 mRNA levels. Additionally, the occurrence of hemorrhage, inflammatory cell infiltration, and thickening of alveolar walls decreased following treatment with vitamin D + Mg. Although Cd did not affect the newborns' body weight, it did impair their lung function. These findings suggest that the Cd-induced increase in the P53 gene expression could be alleviated by vitamin D and Mg, along with the elevation of VEGF and BMP-4 proteins and Foxo1 gene expression. The study revealed that environmental toxins can sometimes harm molecules and proteins, leading to damage in critical fetal tissues. However, these issues can be mitigated through essential supplements. STRUCTURED ABSTRACT: The increasing role of Cd in the erratic behavior of numerous biological and molecular entities, notably the development of fetal lung tissue, has made it beneficial to investigate the possible adverse effects of Cd exposure in pregnant mothers and fetal organ development, where instinctive molecular events occur. Researchers are encouraged to create new aspects of medications to reduce clinical symptoms and improve the quality of life due to exposure to metal toxins, particularly in industrialized countries. The present study aimed to evaluate histopathological and molecular modifications of fetal lungs caused by maternal Cd toxicosis and evaluate the possible ameliorating effects of vitamin D and Mg alone and in combination with fetal lung developmental abnormalities, followed by maternal toxin induction, which can be generalized to humans. Fifty female Wistar rats were purchased from the Pasteur Institute of Iran. To induce the model, cadmium at a dose of 2 mg/kg body weight was injected intraperitoneally into the female rats over 28 days before mating (5 days after injection in a week). Afterward, the female rats were randomly divided into type IV polycarbonate cages and mated with healthy male rats. The pregnancy was confirmed by observation of the vaginal plaque, which was subsequently observed, and the number of days of embryo formation was calculated. Subsequently, the pregnant rats were assigned to the following groups and received PBS, vitamin D, Mg, or vitamin D + Mg. At the end of the nine-day treatment period (the 6th day of pregnancy to the 14th day), the neonates were born vaginally, and their body weight and mortality were recorded. The P53 and Foxo1 gene expression levels in the left and right lobes of the homogenized lungs of the newborns in each group were assessed. TNF-alpha was detected in the sera collected from the newborns by ELISA. The isolated left and right lung tissues were homogenized in radioimmunoprecipitation assay (RIPA) buffer and the superior phase was collected to determine the total protein content by Lowry's method and VEGF and BMP-4 protein levels. The obtained lung samples from newborn rats were fixed in a 10% formalin solution for tissue processing. The fixed samples were embedded in paraffin, and serial paraffin sections were prepared for hematoxylin and eosin staining. This study is the first to examine how maternal Cd exposure affects fetal lung development and to estimate the impact of prescribing Mg and vitamin D during pregnancy. The present study assessed the effects of a repeated dose of Cd for 4 weeks before pregnancy on the lung development of newborn rats born to mothers treated with vitamin D and Mg. The results showed that the P53 gene was overexpressed in the model group, while Foxo1 gene expression was downregulated, negatively impacting the lung structure and developmental indices of the fetuses. Therefore, the intake of vitamin D and Mg may contribute to improving the various stages of Cd-induced lung injury by modulating lung inflammation and mucosal secretion while also positively influencing the number of surviving offspring.

Association of Maternal Gestational Vitamin D Supplementation with Respiratory Health of Young Children

This study aimed to evaluate the association between maternal gestational Vitamin D3 supplementation and early respiratory health in offspring. This was a population-based record-linkage study which used data from the French National Health Database System. Maternal Vitamin D3 supplementation consisted of a single high oral dose of cholecalciferol, (100,000 IU) from the seventh month of pregnancy, according to national guidelines. In total, 125,756 term-born singleton children were included, of which 37% had respiratory illness defined as hospital admission due to respiratory causes or inhalation treatment up to 24 months of age. Infants prenatally exposed to maternal Vitamin D3 supplementation (n = 54,596) were more likely to have a longer gestational age (GA) at birth (GA 36-38 weeks, 22% vs. 20%, p < 0.001 in exposed vs. non-exposed infants, respectively). After adjusting for the main risk factors (maternal age, socioeconomic level, mode of delivery, obstetrical and neonatal pathology, birth weight appropriateness, sex, and birth season), the risk of RD was found to be 3% lower than their counterparts (aOR [IC 95%], 0.97 [0.95-0.99], p = 0.01). In conclusion, this study provides evidence for the association between maternal gestational Vitamin D3 supplementation and improved early respiratory outcomes in young children.

Utility of umbilical cord blood 25-hydroxyvitamin D levels for predicting bronchopulmonary dysplasia in preterm infants with very low and extremely low birth weight

BACKGROUND AND OBJECTIVE

There remains controversy regarding vitamin D deficiency and bronchopulmonary dysplasia (BPD) in very low birth weight (VLBW) and extremely low birth weight (ELBW) preterm infants. This study aimed to determine the prevalence of vitamin D deficiency assessed by umbilical cord blood 25-hydroxyvitamin D [25(OH)D] in preterm infants in northeast China and to evaluate the ability and optimal threshold of 25(OH)D for predicting BPD.

METHODS

The clinical data of VLBW and ELBW preterm infants with known cord-blood 25(OH)D levels were analyzed retrospectively. Infants were divided into groups based on their cord-blood 25(OH)D levels and BPD diagnosis. Logistic regression was performed to assess the risk factors for BPD and a nomogram was established. Receiver operating characteristic (ROC) curve analysis was used to evaluate the optimal threshold of cord-blood 25(OH)D concentration for predicting BPD.

RESULTS

A total of 267 preterm infants were included, of which 225 (84.3%) exhibited vitamin D deficiency and 134 (50.2%) were diagnosed with BPD. The incidence of BPD was lower in the group with a 25(OH)D level of >20 ng/ml than in the other groups (P = 0.024). Infants with BPD had lower cord-blood 25(OH)D levels than those without BPD (11.6 vs. 13.6 ng/ml, P = 0.016). The multivariate logistic regression model revealed that 25(OH)D levels (odds ratio [OR] = 0.933, 95% confidence interval [95% CI]: 0.891-0.977), gestational age (OR = 0.561, 95% CI: 0.425-0.740), respiratory distress syndrome (OR = 2.989, 95% CI: 1.455-6.142), and pneumonia (OR = 2.546, 95% CI: 1.398-4.639) were independent risk factors for BPD. A predictive nomogram containing these four risk factors was established, which had a C-index of 0.814. ROC curve analysis revealed that the optimal cutoff value of 25(OH)D for predicting BPD was 15.7 ng/ml (area under the curve = 0.585, 95% CI: 0.523-0.645, P = 0.016), with a sensitivity of 75.4% and a specificity of 42.9%.

CONCLUSIONS

A cord-blood 25(OH)D level of <15.7 ng/ml was predictively valuable for the development of BPD. The nomogram established in this study can help pediatricians predict the risk of BPD more effectively and easily.

Current Overview on Therapeutic Potential of Vitamin D in Inflammatory Lung Diseases

Inflammatory lung disorders (ILDs) are one of the world's major reasons for fatalities and sickness, impacting millions of individuals of all ages and constituting a severe and pervasive health hazard. Asthma, lung cancer, bronchiectasis, pulmonary fibrosis acute respiratory distress syndrome, and COPD all include inflammation as a significant component. Microbe invasions, as well as the damage and even death of host cells, can cause and sustain inflammation. To counteract the negative consequences of irritants, the airways are equipped with cellular and host defense immunological systems that block the cellular entrance of these irritants or eliminate them from airway regions by triggering the immune system. Failure to activate the host defense system will trigger chronic inflammatory cataracts, leading to permanent lung damage. This damage makes the lungs more susceptible to various respiratory diseases. There are certain restrictions of the available therapy for lung illnesses. Vitamins are nutritional molecules that are required for optimal health but are not produced by the human body. Cholecalciferol (Vitamin D) is classified as a vitamin, although it is a hormone. Vitamin D is thought to perform a function in bone and calcium homeostasis. Recent research has found that vitamin D can perform a variety of cellular processes, including cellular proliferation; differentiation; wound repair; healing; and regulatory systems, such as the immune response, immunological, and inflammation. The actions of vitamin D on inflammatory cells are dissected in this review, as well as their clinical significance in respiratory illnesses.

Vitamin D Actions: The Lung Is a Major Target for Vitamin D, FGF23, and Klotho

Vitamin D is well known for its role as a calcium regulator and in maintenance of phosphate homeostasis in musculoskeletal health, and fibroblast growth factor 23 (FGF23) and its coreceptor α-klotho are known for their roles as regulators of serum phosphate levels. However, apart from these classical actions, recent data point out a relevant role of vitamin D and FGF23/klotho in lung health. The expression of the vitamin D receptor by different cell types in the lung and the fact that those cells respond to vitamin D or can locally produce vitamin D indicate that the lung represents a target for vitamin D actions. Similarly, the presence of the four FGF receptor isoforms in the lung and the ability of FGF23 to stimulate pulmonary cells support the concept that the lung is a target for FGF23 actions, whereas the contribution of klotho is still undetermined. This review will give an overview on how vitamin D or FGF23/klotho may act on the lung and interfere positively or negatively with lung health. © 2021 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

Pulmonary surfactant-associated protein B regulates prostaglandin-endoperoxide synthase-2 and inflammation in chronic obstructive pulmonary disease

NEW FINDINGS

What is the central question of this study? It is reported that polymorphism of the gene for pulmonary surfactant-associated protein B (SFTPB) is associated with chronic obstructive pulmonary disease (COPD): what are the function and mechanism of action of SFTPB in COPD? What is the main finding and its importance? Under stimulation of the risk factors of COPD, SFTPB expression is decreased, which may be involved in the formation of COPD. The progress of COPD induces an inflammatory response and reduces SFTPB expression. Levels of prostaglandin-endoperoxide synthase-2 (PTGS2) and inflammatory responses are changed by SFTPB, which indicates that SFTPB promotes the progression of COPD by PTGS2 and inflammation.

ABSTRACT

Pulmonary surfactant-associated protein B (SFTPB) is a critical protein for lung homeostasis, and polymorphism of its gene is associated with chronic obstructive pulmonary disease (COPD). However, few studies have so far confirmed the functional involvement of SFTPB in COPD. Serum SFTPB and inflammatory cytokine levels were measured in 54 patients with acute exacerbation of COPD and 29 healthy controls. A549 cells were induced using 10% cigarette smoke extract (CSE) and treated with dexamethasone to investigate the effect of inflammation on SFTPB expression, and the effect of SFTPB overexpression and silencing on inflammatory cytokines was measured using real-time PCR and enzyme-linked immunosorbent assay. SFTPB expression was assessed in mouse lung tissues using immunofluorescence. Serum levels of SFTPB were significantly lower in COPD patients than in controls (P = 0.009). Conversely, levels of interleukin (IL)-6 and prostaglandin-endoperoxide synthase-2 (PTGS2) were increased in COPD patients (IL-6: P = 0.006; PTGS2: P = 0.043). After CSE treatment, SFTPB mRNA and protein levels were significantly decreased compared to controls (mRNA: P = 0.002; protein: P = 0.011), while IL-6, IL-8 and PTGS2 were elevated. Dexamethasone treatment increased SFTPB levels. Following overexpression of SFTPB in A549 cells, mRNA and protein levels of IL-6, IL-8 and PTGS2 were significantly reduced, while gene silencing induced the opposite effect. SFTPB levels were significantly reduced in the lung tissue of a mouse model of COPD compared to controls. Reduced SFTPB levels may induce PTGS2 and inflammatory responses in COPD and SFTPB could be a key protein for evaluation of COPD progression.

Biodistribution, inter-/intra-cellular localization and respiratory dysfunction induced by Ti3C2 nanosheets: Involvement of surfactant protein down-regulation in alveolar epithelial cells

Two-dimensional Ti₃C₂ nanosheets have been extensively used in biomedical fields and are mostly designed to enter the circulatory system. However, few studies have focused on the in vivo anatomical location and physiological function of major organs on exposure to Ti₃C₂ nanosheets. This study attempts to determine whether and how Ti₃C₂ nanosheets disrupt the physiological function of the involved organs. Our studies demonstrated that Ti₃C₂ nanosheets were mainly distributed in the lungs and liver after entering circulation. In the lungs, they were retained in the cytoplasm of alveolar epithelial cells and endothelial cells, and inhibited pulmonary surfactant protein B (SP-B) expression on alveolar epithelial cell, causing increased airway resistance-induced respiratory disorder following a 28-day Ti₃C₂ nanosheet exposure. Furthermore, our data showed that Ti₃C₂ nanosheets did not cause abnormal proinflammatory cytokines and histopathological changes. These findings demonstrated that Ti₃C₂ nanosheets might disturb respiration without inflammatory responses and pathological lesions, suggesting that these effects may occur by decreasing SP-B-mediated airway resistance. This indicates that organ function maintenance differs from biological safety for Ti₃C₂ nanosheets, an important consideration during potential clinical application and human exposure.

Low Vitamin D Levels at Birth and Early Respiratory Outcome in Infants With Gestational Age Less Than 29 Weeks

BACKGROUND

Vitamin D (VitD) is involved in lung development but its influence on respiratory distress syndrome of extremely preterm (EPT) infants have been little investigated. In this study, we examined the influence of low vitamin D status at birth on early respiratory outcomes of this vulnerable infant population.

METHODS

Cord blood 25(OH)D levels ≤ 75 nmol/L were considered as Low vitamin D levels. Stepwise logistic regression and classification regression-tree analyses were used and the primary outcome was the combined outcome of death or mechanical ventilation need by the end of the first week (death or MV DoL7) as a marker od RDS severity.

RESULTS

The mean (SD) GA and birth weight were 26 (1.4) weeks and 801 (212) gr, respectively; 81/109 (74%) infants had low 25(OH)D levels. Infants with low VitD levels had 25% higher initial FiO₂ levels (p < 0.05) and were more likely to be mechanically ventilated on DoL7 (36 vs. 7%, p < 0.05). Adjusted for gestational age, they had 10-fold higher odds of death or MV DoL7 (p < 0.01). By regression tree analysis, the rate of death or MV DoL7 increased from 18 to 71% in infants with GA < 26 weeks and with cord blood 25(OH)D levels higher and lower than 74 nmol/L, respectively (p < 0.05).

CONCLUSION

Low vitamin D levels at birth are associated with early adverse respiratory outcomes in infants with GA less 29 weeks. Further largest studies are needed to confirm this association.