The impact of vitamin D on fetal and neonatal lung maturation. A systematic review

Assessment of growth status and nutritional management of prematurely born infants after hospital discharge: A position paper of the ESPGHAN Nutrition Committee

OBJECTIVES

The aim of the manuscript is to provide evidence-based or expert consensus-based recommendations for growth assessment and nutritional management of preterm-born infants during the post-discharge period.

METHODS

The search was conducted in Pubmed, MEDLINE, EMBASE, and Cochrane Database of Systematic Reviews using the MESH terms: infant, preterm infant, low birth weight, infant food, nutritional status, nutrients, breast feeding, infant formula, human milk, dietary supplements, vitamins, iron, vitamin D, minerals, energy intake, weaning, and baby led. Overall, 402 papers were identified and screened, from which 101 publications were included in the present position paper. In the absence of evidence, recommendations reflect the authors' combined expert opinion. Final consensus was obtained through multiple e-mail exchanges and meetings with the Committee of Nutrition of the European Society for Paediatric Gastroenterology, Hepatology, and Nutrition.

RESULTS

Continuous growth monitoring through measurements of weight, length, and HC post-discharge is recommended to identify growth faltering (GF) or undernutrition. To prevent disproportionate growth, weight-for-length z-scores should be included in the assessment when term equivalent age is reached. Infants discharged with a significant drop in weight and length, exceeding a -2 standard deviation loss, require tailored nutritional support to address long-term growth challenges and to support recovery to normal growth rates. Breastfeeding is highly recommended for all infants when feasible. Infants needing to catch up in growth should be given supplements, such as HMF For those fed with formula, an adequate protein: energy ratio, minerals, and trace elements should be supplied to facilitate catch-up growth. The start of solid foods should coincide with the infant's neurological developmental milestones, rather than adhering strictly to a set age. Vitamin D and iron supplementation (with regular ferritin monitoring) is recommended through at least 12 months CA.

CONCLUSION

For preterm infants, close monitoring of growth after discharge and nutritional assessment is essential to identify those at high risk for GF or undernutrition and to provide individualized nutritional support when needed. These patients should either be referred to a specialized center for pediatric nutritional care or, alternatively, their general pediatrician should receive appropriate training on the subject.

Vitamin D: What We Know and What We Still Do Not Know About Vitamin D in Preterm Infants-A Literature Review

BACKGROUND/OBJECTIVES

Preterm infants represent a population group at increased risk for vitamin D deficiency (VDD) and for its negative impact on various outcomes like metabolic bone disease or rickets, respiratory complications like respiratory distress syndrome and the development of bronchopulmonary dysplasia, necrotizing enterocolitis, or retinopathy of prematurity.

METHODS

Despite the growing interest in vitamin D research, there is still uncertainty regarding clear recommendations for each high-risk category of premature infants concerning the optimal dosage, optimal product, and timing for initiating vitamin D supplementation to prevent VDD.

RESULTS

An analysis of the literature suggests that early intervention for the optimal enteral supplementation of vitamin D is not only successful in achieving higher 25-hydroxi-vitamin D (25(OH)D) at one month but is also linked with improved outcomes.

CONCLUSIONS

The traditional concepts and current recommendations for assessing vitamin D status and optimal supplementation need to be revised. Since parenteral nutrition, fortified mothers' own milk, and special formula for preterm infants cannot provide adequate vitamin D levels, initiating oral supplementation soon after birth is essential to correct VDD in preterm infants.

Evaluation of vitamin D in the diagnosis of infants with respiratory distress, the clinical value: A systematic review and meta-analysis

INTRODUCTION

Respiratory distress (RD) is the most common cause of admission to the Neonatal Intensive Care Unit (NICU). The role of Vitamin D in the development and fortification of fetal pulmonary architecture and the synthesis of surfactants is well-documented. While different serum levels of 25-hydroxyvitamin D (Vit. D) have been studied for their diagnostic significance in RD, there is limited research on how it specifically affects the development of respiratory problems in infants and their mothers. The purpose of the present study is a systematic review and meta-analysis to evaluate the correlation between serum levels of Vit. D in mothers and newborns with RD, and to determine the impact of treating either population on the clinical outcomes of afflicted infants.

METHODS

A comprehensive literature search was conducted across various databases, including PubMed, ScienceDirect, Cochrane Library, ISI, and Google Scholar, using a combination of keywords such as RD, diagnosis, vitamin D, mothers, infants, vitamin D supplementation, Respiratory distress syndrome(RDS), and Transient Tachypnea of Newborn (TTN). The search was carried out until March 2024.The level of vitamin D in both mothers and their infants was systematically extracted and analyzed to determine the diagnostic efficacy of Vit. D levels. The mean difference (MD) was calculated along with a 95% confidence interval to determine the association between the Vit. D levels in newborns and their mothers and the likelihood of RD, RDS and TTN in infants. To assess potential publication bias, a funnel plot was generated and Egger's regression test was applied, utilizing a random-effects model.

RESULTS

Initially a total of 298 relevant articles was retrieved. Among them, 17 articles with a total of 1,582 infants (745 cases and 837 healthy controls) met the criteria as eligible studies. Of these six were prospective cohort studies, four retrospective case-control studies, four randomized controlled trials (RCTs), and three descriptive-analytical studies. The meta-results revealed a significant association between Vit. D levels and risk of RD in infants (MD = 6.240, 95 %CI: 4.840-7.840, P < 0.001) and mothers (MD = 8.053, 95 %CI: 4.920-11.186, P < 0.001). Furthermore, a strong association was found for risk of RDS (MD = 5.493, 95 %CI: 3.356-7.631, P < 0.001) in infants and TTN (MD = 6.672, 95 %CI: 4.072-9.272, P < 0.001), (MD = 8.595, 95%CI: 4.604-12.586, P < 0.001) both in infants and mothers. Administering 50,000 units of vitamin D to mothers (MD = 8.595, 95 %CI: 4.604-12.586, P < 0.001) prior to childbirth was observed to reduce the likelihood of RD in newborns by 64 % (RR = 0.36, 95 %CI: 0.23-0.57, P < 0.001). Supplemental vitamin D provided to infants was associated with several clinical benefits.

CONCLUSION

Our meta-results indicated a significant correlation between serum levels of Vit. D and the risk of RD, RDS and TTN in infants. Prophylactic maternal administration of vitamin D plays a protective role against neonatal RD. Additionally, providing vitamin D to premature infants has shown a significant impact in reducing the incidence of respiratory complications.

Survey of vitamin D supplementation practices in extremely preterm infants

BACKGROUND

Most extremely preterm (EP) infants are vitamin D deficient (serum 25-hydroxyvitamin D levels below 20 ng/mL), and optimal supplementation practices for EP infants remain unknown. Our objective is to assess current vitamin D supplementation practices in U.S. neonatal intensive care units (NICU) for EP infants to provide baseline information for the design of future clinical trials.

METHODS

We conducted an online survey to study vitamin D intake and supplementation practices in U.S. NICUs caring for EP infants. Descriptive statistics compared responses by affiliation and level of care.

RESULTS

We analyzed responses from 253 NICUs, representing the majority of academic and level IV centers. Nearly all centers (97%) provided enteral vitamin D supplementation during the NICU stay, with 400 IU/day as the most common dosage (77%). Over half (56%) used feeding volume to initiate supplementation, with 71% of centers starting after achieving at least 120 ml/kg/day. Additionally, 94% of NICUs reported prescribing a vitamin D supplementation at discharge.

CONCLUSIONS

Most NICUs in the U.S. supplement EP infants with 400 IU/day of enteral vitamin D. Clinical trials of vitamin D supplementation comparing the most common regimen to earlier and higher doses are needed to identify adequate regimens for EP infants.

IMPACT

Despite the prevalence of vitamin D deficiency in extremely preterm (EP) infants at birth, optimal levels and supplementation strategies remain debated. Recent studies have suggested benefits of early high-dose vitamin D supplementation (800 IU/day) for reducing complications like bronchopulmonary dysplasia, infections, and disability. There is US center variation in timing and dose of vitamin D supplementation, being the most common regimen 400 IU/d started after established feedings (≥120 ml/kg/day). These findings inform and highlight the need for clinical trials of usual vs. early, higher-dose vitamin D supplementation to advance clinical outcomes and define desirable blood levels of EP infants.

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.

Risk factors and outcomes of vitamin D deficiency in very preterm infants

BACKGROUND

Vitamin D is essential for bone health and immune system. Vitamin D deficiency (VDD) poses a high-risk to very preterm (VP) infants. This study aimed to evaluate the risk factors associated with VDD in VP infants and its potential clinical outcomes.

METHODS

A retrospective cohort study was conducted on VP infants admitted to the neonatal intensive care unit of a specialized tertiary hospital in Seoul, Republic of Korea, between January 2018 and June 2022. Serum 25-hydroxyvitamin D (25(OH)D) levels and other biochemical parameters were measured between 4 and 6 weeks of age. VDD was defined as a serum 25(OH)D level <20 ng/mL. Prenatal and postnatal risk factors and clinical outcomes were compared between the VDD and non-VDD groups.

RESULTS

Of the 82 VP infants analyzed, 27 (32.9%) were diagnosed with VDD. The VDD group exhibited a significantly longer duration of parenteral nutrition (PN) compared to the non-VDD group (adjusted odds ratio [OR] = 1.12; 95% confidence interval [CI]: 1.008-1.245). Breast milk intake was lower in the VDD group than in the non-VDD group (adjusted OR = 0.976, 95% CI, 0.955-0.999). Notably, calcium levels were significantly lower in the VDD group, while parathyroid hormone levels were significantly higher, compared with the non-VDD group. Additionally, the rickets severity score was higher in the VDD group than in the non-VDD, although the difference was not statistically significant.

CONCLUSIONS

Prolonged PN duration and low breast milk intake significantly increased the risk of VDD in VP infants.

Impact of vitamin D on hyperoxic acute lung injury in neonatal mice

BACKGROUND

Prolonged exposure to hyperoxia can lead to hyperoxic acute lung injury (HALI) in preterm neonates. Vitamin D (VitD) stimulates lung maturation and acts as an anti-inflammatory agent. Our objective was to determine if VitD provides a dose-dependent protective effect against HALI by reducing inflammatory cytokine expression and improving alveolarization and lung function in neonatal mice.

METHODS

C57BL/6 mouse neonates were randomized and placed in room air or hyperoxic (85% O2) conditions for 6 days. Control, low (5 ng/neonate) and high (25 ng/neonate) doses of VitD were administered daily beginning at day 2 via oral gavage. Lung tissue was analyzed for edema, changes in pulmonary structure and function, and inflammatory cytokine expression.

RESULTS

Neonatal mice treated with VitD in hyperoxic conditions had improved weight gain, reduced pulmonary edema and increased alveolar surface area compared to untreated pups in hyperoxia. No significant changes in cytokine expression were observed between untreated and VitD neonates. While changes in surfactant protein mRNA expression were impacted by hyperoxia and VitD administration, no significant changes in alveolar type II cell percentages were observed. At 3 weeks, mice in hyperoxia treated with VitD had greater lung compliance, diminished airway reactivity and improved weight gain.

CONCLUSIONS

High dose VitD significantly limited harmful effects of HALI. These results suggest that supplementation of VitD to neonatal mice during hyperoxia exposure provides both short-term and long-term protective benefits against HALI.

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.

Influence of vitamin D supplementation on muscle strength and exercise capacity in South African schoolchildren: secondary outcomes from a randomised controlled trial (ViDiKids)

Objective

To determine whether vitamin D supplementation influences grip strength, explosive leg power, cardiorespiratory fitness and risk of exercise-induced bronchoconstriction (EIB) in South African schoolchildren.

Methods

Substudy (n=450) in Cape Town schoolchildren aged 8-11 years nested within a phase 3 randomised placebo-controlled trial (ViDiKids). The intervention was weekly oral doses of 10 000 IU vitamin D3 (n=228) or placebo (n=222) for 3 years. Outcome measures were serum 25-hydroxyvitamin D3 (25(OH)D3) concentrations, grip strength, standing long jump distance, peak oxygen uptake (VO2peak, determined using 20 m multistage shuttle run tests) and the proportion of children with EIB, measured at end-study.

Results

64.7% of participants had serum 25(OH)D3concentrations <75 nmol/L at baseline. At 3-year follow-up, children randomised to vitamin D versus placebo had higher mean serum 25(OH)D3 concentrations (97.6 vs 58.8 nmol/L, respectively; adjusted mean difference 39.9 nmol/L, 95% CI 36.1 to 43.6). However, this was not associated with end-study differences in grip strength, standing long jump distance, VO2peak or risk of EIB.

Conclusion

A 3-year course of weekly oral supplementation with 10 000 IU vitamin D3 elevated serum 25(OH)D3 concentrations in South African schoolchildren but did not influence muscle strength, exercise capacity or risk of EIB.

Influence of vitamin D supplementation on muscle strength and exercise capacity in Mongolian schoolchildren: secondary outcomes from a randomised controlled trial

Objective

To determine whether weekly oral vitamin D supplementation influences grip strength, explosive leg power, cardiorespiratory fitness or spirometric lung volumes in Mongolian schoolchildren.

Methods

Multicentre, randomised, placebo-controlled clinical trial conducted in children aged 6-13 years at baseline attending 18 schools in Ulaanbaatar. The intervention was weekly oral doses of 14 000 IU vitamin D3 (n=4418) or placebo (n=4433) for 3 years. Outcome measures were grip strength, standing long jump distance and serum 25-hydroxyvitamin D (25(OH)D) concentrations (determined in all participants), peak oxygen uptake (VO2peak, determined in a subset of 632 participants using 20 m multistage shuttle run tests) and spirometric outcomes (determined in a subset of 1343 participants).

Results

99.8% of participants had serum 25(OH)D concentrations <75 nmol/L at baseline, and mean end-study 25(OH)D concentrations in children randomised to vitamin D versus placebo were 77.4 vs 26.7 nmol/L (mean difference 50.7 nmol/L, 95% CI 49.7 to 51.4). However, vitamin D supplementation did not influence mean grip strength, standing long jump distance, VO2peak, spirometric lung volumes or peak expiratory flow rate, either overall or within subgroups defined by sex, baseline 25(OH)D concentration <25 vs ≥25 nmol/L or calcium intake <500 vs ≥500 mg/day.

Conclusion

A 3-year course of weekly oral supplementation with 14 000 IU vitamin D3 elevated serum 25(OH)D concentrations in Mongolian schoolchildren with a high baseline prevalence of vitamin D deficiency. However, this intervention did not influence grip strength, explosive leg power, peak oxygen uptake or spirometric lung volumes, either overall or in subgroup analyses.

Trial registration number

NCT02276755.

Vitamin D and gut microbiome in preterm infants

BACKGROUND

The incidence of vitamin D deficiency among pregnant women remains high and is associated with vitamin D deficiency in infants. In normally breastfed infants, Bifidobacteriaceae and Lactobacillaceae are known to help in maintaining immunotolerance and prevent infection. Vitamin D in the gastrointestinal tract plays a role in determining the composition and function of intestinal bacteria. Preterm infants are vulnerable to intestinal dysbiosis and sepsis due to bacterial translocation. This study aimed to determine the association between vitamin D levels and intestinal dysbiosis.

METHODS

It was a cohort study conducted in the Neonatal Unit, Cipto Mangunkusumo Hospital, Tertiary hospital in Indonesia, from November 2019 to January 2021. The inclusion criteria in this study were preterm infants with a gestational age of less than 32 weeks or a birth weight of less than 1500 g. Total 25-hydroxyvitamin D (25(OH)D) levels were collected from the umbilical cords of very preterm or very low birth weight infants. A fecal examination was performed on the seventh day of life to assess intestinal bacteria using real-time PCR for four bacterial genera: Bifidobacteriaceae, Lactobacillaceae, Enterobacteriaceae, and Clostridiaceae.

RESULTS

A total of 43 infants were included in this study. Among the subjects, 53.4% had vitamin D deficiency. There was no association identified between vitamin D deficiency and intestinal dysbiosis (RR 0.67; 95% CI (0.15-2.82), p-value = 0.531). However, the ratio of Lactobacillacecae to Enterobacteriaceae was lower in those with vitamin D deficiency.

CONCLUSION

Vitamin D deficiency was not associated with dysbiosis in preterm infants. However, this study found that the ratio of Lactobacillaceae to Enterobacteriaceae in those with vitamin D deficiency was lower than in those without vitamin D deficiency. Further research is warranted to confirm this finding.

Influence of vitamin D supplementation on muscle strength and exercise capacity in Mongolian schoolchildren: a randomised controlled trial

Objective

To determine whether weekly oral vitamin D supplementation influences grip strength, explosive leg power, cardiorespiratory fitness or spirometric lung volumes in Mongolian schoolchildren.

Methods

Multicentre, randomised, double-blind, placebo-controlled clinical trial conducted in children aged 6-13 years at baseline attending 18 schools in Ulaanbaatar. The intervention was weekly oral doses of 14,000 IU vitamin D3 (n=4418) or placebo (n=4433) for 3 years. Outcome measures were grip strength, standing long jump distance and serum 25-hydroxyvitamin D (25[OH]D) concentrations (determined in all participants), peak oxygen uptake (VO2peak, determined in a subset of 632 participants using 20-metre multi-stage shuttle run tests) and spirometric outcomes (determined in a subset of 1,343 participants).

Results

99.8% of participants had serum 25(OH)D concentrations <75 nmol/L at baseline, and mean end-study 25(OH)D concentrations in children randomised to vitamin D vs. placebo were 77.4 vs. 26.7 nmol/L (mean difference 50.7 nmol/L, 95% CI, 49.7 to 51.4). However, vitamin D supplementation did not influence mean grip strength, standing long jump distance, VO2peak, spirometric lung volumes or peak expiratory flow rate, either overall or within sub-groups defined by sex, baseline 25(OH)D concentration <25 vs. ≥25 nmol/L or calcium intake <500 vs. ≥500 mg/day.

Conclusion

A 3-year course of weekly oral supplementation with 14,000 IU vitamin D3 elevated serum 25(OH)D concentrations in Mongolian schoolchildren with a high baseline prevalence of vitamin D deficiency. However, this intervention did not influence grip strength, explosive leg power, peak oxygen uptake or spirometric lung volumes, either overall or in sub-group analyses.

Prenatal vitamin D supplementation to prevent childhood asthma: 15-year results from the Vitamin D Antenatal Asthma Reduction Trial (VDAART)

This article provides an overview of the findings obtained from the Vitamin D Antenatal Asthma Reduction Trial (VDAART) spanning a period of 15 years. The review covers various aspects, including the trial's rationale, study design, and initial intent-to-treat analyses, as well as an explanation of why those analyses did not achieve statistical significance. Additionally, the article delves into the post hoc results obtained from stratified intent-to-treat analyses based on maternal vitamin D baseline levels and genotype-stratified analyses. These results demonstrate a statistically significant reduction in asthma among offspring aged 3 and 6 years when comparing vitamin D supplementation (4400 IU/d) to the standard prenatal multivitamin with vitamin D (400 IU/d). Furthermore, these post hoc analyses found that vitamin D supplementation led to a decrease in total serum IgE levels and improved lung function in children compared to those whose mothers received a placebo alongside the standard prenatal multivitamin with vitamin D. Last, the article concludes with recommendations regarding the optimal dosing of vitamin D for pregnant women to prevent childhood asthma as well as suggestions for future trials in this field.

Implications of maternal vitamin D administration for the neonatal respiratory distress syndrome: A randomized clinical trial

BACKGROUND

Vitamin D deficiency has been suggested to be a risk factor for neonatal respiratory distress syndrome (RDS). This study aimed to evaluate the effect of 25 (OH) D administrations in pregnant women with findings of preterm labor on the incidence of RDS in their preterm neonates.

MATERIALS AND METHODS

A randomized controlled clinical trial was conducted on pregnant mothers with gestational age (GA) of less than 34 weeks at risk of preterm delivery. 175 subjects were randomly assigned into two groups, including intervention (intramuscular injection of 50,000 units of 25(OH) D during 72 hours before delivery) and control (no injections). Serum concentrations of 25(OH) D were measured shortly after birth in both mothers and neonates. Then, clinical and laboratory results of mothers and their offspring were recorded (in a checklist). Short-term outcomes and the need for respiratory support were also assessed. Data were analyzed by independent t-test, Mann-Whitney U test, Fisher's exact test, and chi-square test.

RESULTS

Even though gestational age, birth weight, delivery method, and serum vitamin D levels are consistent among both groups, 45% of neonates in the control group and 20% in the intervention group developed respiratory distress syndrome (P = 0.05). The mean 25(OH) D level in neonates was 17.7±10.5 and 19.29±9.94 ng/mL in the intervention and control groups, respectively (P > 0.05).

CONCLUSION

A single dose of 50,000 units of intramuscular 25(OH)D in pregnant women at risk of preterm labor can lower the risk of RDS in the infant.

Is 25OH Vitamin D Excess before 36 Weeks Corrected Age an Independent Risk Factor for Bronchopulmonary Dysplasia or Death?

Low 25-Hydroxyvitamin D (25(OH)D) in preterm infants is a risk factor for bronchopulmonary dysplasia (BPD), but increased supplementation failed to demonstrate a beneficial effect on BPD. In neonatal animal models, deficiency and excessive vitamin D exposure have been associated with increased mortality and histological alterations in the lung evocative of BPD. Our hypothesis is that 25(OH)D levels ≥ 120 nmol/L are also a risk factor for BPD or death. This retrospective single-center cohort study included only infants born at <31 weeks gestational age without major malformations with at least a determination of 25(OH)D at <36 weeks corrected age and no determination <50 nmol/L. Routine 25(OH)D determination was performed at 1 month and monthly thereafter. A total of 175 infants were included. Infants with BPD or who died had a significantly lower term and weight, but a similar frequency of 25(OH)D ≥120 nmol/L (50.5% vs. 43.9%, p = 0.53). The logistic regression identified weight (OR 0.997, 95% CI [0.995-0.998]) and term (OR 0.737, 95% CI [0.551-0.975]) as significantly associated with BPD or death; the occurrence of excessive 25(OH)D was not significantly associated (OR 1.029, 95% CI [0.503-2.093]). The present study did not demonstrate any significant association between excessive 25(OH)D after one month of age and BPD or death.

The effect of maternal vitamin D deficiency during pregnancy on glycolipid metabolism of offspring rats and the improvement of vitamin D intervention after weaning

Background

Vitamin D deficiency during pregnancy is common, but whether maternal vitamin D status affects glycolipid metabolism of offspring remains unclear.

Objective

To evaluate the effect of maternal vitamin D deficiency during pregnancy on the glycolipid metabolism of offspring at different life-cycles (from birth to adulthood) and to explore the improvement of different dosages of vitamin D supplementation.

Methods

Sprague-Dawley rats were fed vitamin D-deprived (VDD group) or standard vitamin D diets (SC group) during pregnancy, and their diets were changed to standard vitamin D diets during lactation (the offspring were sorted into VDDoffspring and SCoffspring groups). After weaning, rats in the VDDoffspring group were randomly assigned to the VDDoffspring, VDDoffspring-S3300 and VDDoffspring-S10000 groups with diets containing standard, medium and high dosages of vitamin D for 12 wk. Serum was collected for biochemical analyses at postnatal Day 21, postnatal Day 56 and postnatal Day 84. Oral glucose tolerance test (OGTT) was performed at postnatal Day 70.

Results

Compared to SCoffspring, rats in the VDDoffspring group had significantly lower birth weight with faster weight gain and higher levels of lipid metabolism in early life. After near adulthood, the differences in weight and lipid metabolism between the two groups disappeared. OGTT showed significantly higher blood glucose levels in the VDDoffspring group at 30 min, 60 min, and 90 min. The continuation of vitamin D supplementation at medium and high dosages after weaning did not cause any obvious changes in weight or glycolipid metabolism (except for postprandial hyperglycemia). OGTT demonstrated that the glucose levels in the VDDoffspring-S3300 group were lowest at all the time points and that those in the VDDoffspring-S10000 group were the highest at 30 min, 60 min, and 90 min among the three groups.

Conclusion

The adverse effects of vitamin D deficiency during pregnancy on glycolipid metabolism in offspring vary in different stages. Over a long time period, adequate vitamin D supplementation is beneficial to glycolipid metabolism for the offspring of subjects with vitamin D deficiency during pregnancy; however, further improvement is required.

Bronchopulmonary Dysplasia: Pathogenesis and Pathophysiology

Bronchopulmonary dysplasia (BPD), also known as chronic lung disease, is the most common respiratory morbidity in preterm infants. "Old" or "classic" BPD, as per the original description, is less common now. "New BPD", which presents with distinct clinical and pathological features, is more frequently observed in the current era of advanced neonatal care, where extremely premature infants are surviving because of medical advancements. The pathogenesis of BPD is complex and multifactorial and involves both genetic and environmental factors. This review provides an overview of the pathology of BPD and discusses the influence of several prenatal and postnatal factors on its pathogenesis, such as maternal factors, genetic susceptibility, ventilator-associated lung injury, oxygen toxicity, sepsis, patent ductus arteriosus (PDA), and nutritional deficiencies. This in-depth review draws on existing literature to explore these factors and their potential contribution to the development of BPD.

The Impact of Baseline 25-Hydroxyvitamin D Level and Gestational Age on Prenatal Vitamin D Supplementation to Prevent Offspring Asthma or Recurrent Wheezing

BACKGROUND

Prenatal vitamin D deficiency is associated with asthma or recurrent wheezing in offspring. However, evidence from randomized trials on the efficacy of vitamin D supplementation is inconclusive.

OBJECTIVES

We aimed to examine the differential efficacy of prenatal vitamin D supplementation based on the maternal baseline vitamin D status and the starting time of supplementation to prevent early life asthma or recurrent wheezing.

METHODS

We conducted a secondary analysis of the Vitamin D Antenatal Asthma Reduction Trial (VDAART), a randomized double-blind trial of prenatal vitamin D supplementation initiated at 10-18 weeks (wks) of gestation (4400 IU of intervention/day compared with 400 IU of placebo/day) to prevent offspring asthma or recurrent wheezing by the age of 6 years. We assessed the effect of modification of supplementation by maternal baseline vitamin D status at enrollment and the timing of initiation of supplementation.

RESULTS

An inverse relationship was observed between maternal 25-hydroxyvitamin D (25(OH)D) levels at trial entry and 25(OH)D levels during late pregnancy (32-38 wks of gestation) in both supplementation arms (P < 0.001). Overall, supplementation efficacy was not dependent on the maternal baseline 25(OH)D status. However, a trend toward the reduction of asthma or recurrent wheezing was observed across the baseline groups in the intervention arm (P = 0.01), with the greatest reduction observed in the most severely vitamin D-deficient women (25(OH)D < 12 ng/mL; adjusted odds ratio [aOR] = 0.48; confidence interval [CI]: 0.17, 1.34). Gestational age at trial enrollment modified supplementation efficacy, showing a greater reduction of offspring asthma or recurrent wheezing with earlier intervention during pregnancy (aOR = 0.85; CI = 0.76, 0.95), particularly in women who were 9-12 wk pregnant (aOR = 0.45; CI = 0.24, 0.82).

CONCLUSIONS

Pregnant women with severe vitamin D deficiency show the greatest 25(OH)D improvement because of supplementation. In these women, a vitamin D dose of 4400 IU might have a preventive role in the development of early life offspring asthma or recurrent wheezing. Gestational age is suggested to modify the efficacy of prenatal vitamin D supplementation, showing the highest beneficial effect if supplementation is started during the first trimester of pregnancy. This study is an ancillary analysis from the VDAART, which is registered in ClinicalTrials.gov as NCT00902621.

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.

The Role of Vitamins in the Pathogenesis of Asthma

Vitamins play a crucial role in the proper functioning of organisms. Disturbances of their levels, seen as deficiency or excess, enhance the development of various diseases, including those of the cardiovascular, immune, or respiratory systems. The present paper aims to summarize the role of vitamins in one of the most common diseases of the respiratory system, asthma. This narrative review describes the influence of vitamins on asthma and its main symptoms such as bronchial hyperreactivity, airway inflammation, oxidative stress, and airway remodeling, as well as the correlation between vitamin intake and levels and the risk of asthma in both pre- and postnatal life.

The Effect of Maternal Vitamin D Intake on the Incidence of Nonspecific Respiratory Distress in Infants: A Randomized Clinical Trial

Background: Vitamin D deficiency is associated with respiratory problems in neonates. The late preterm or near-term neonates who have been admitted for tachypnea and fully recovered before 12 h are called non-specific respiratory distress syndrome (NRDS) cases. The present study aimed to evaluate the effect of 25-hydroxy vitamin D administration in pregnant women at risk of preterm delivery on the incidence of NRDS in their newborns. Methods: This single-blind clinical trial was performed on mothers and neonates with a gestational age of 32–37 weeks who were referred with labor pains from February 20, 2021 to June 29, 2021 to the Obstetrics and Gynecology Department and intensive care unit of Ghaem Hospital, affiliated to Mashhad University of Medical Sciences, Iran. Within 72 h before premature delivery, a dose of 50,000 units of 25 hydroxyvitamin D was injected intramuscularly to pregnant women in the intervention group. A sample containing 1.5 mL of whole blood was collected from the umbilical cord of the infant and mother to assess the level of 25-hydroxy vitamin D. Results: In the present study, there was a significant difference between the two groups of control and intervention in terms of infant’s weight (p = 001), 1-minute (p = 0.027) and 5-minute Apgar scores (p = 0.001), the incidence of NRDS (p = 0.001), and the maternal age (p = 0.004). However, the results showed no statistically significant difference between the two groups in terms of gender (p = 0.673), type of delivery (p = 0.299), level of 25-hydroxy(OH) vitamin D of the mother (p = 0.053), and infant (p = 0.805). Conclusions: A single injection of vitamin D into the mother prone to preterm birth over 31 weeks of gestation reduces transient respiratory problems in their newborns. Clinical Trial Registration: The study was also registered in the Iranian Clinical Trial Registration Center (IRCT20110807007244N7).

Alveolar-Capillary Barrier Protection In Vitro: Lung Cell Type-Specific Effects and Molecular Mechanisms Induced by 1α, 25-Dihydroxyvitamin D3

Low serum levels of 1α, 25-dihydroxyvitamin D3 (VD3) are associated with a higher mortality in trauma patients with sepsis or ARDS. However, the molecular mechanisms behind this observation are not yet understood. VD₃ is known to stimulate lung maturity, alveolar type II cell differentiation, or pulmonary surfactant synthesis and guides epithelial defense during infection. In this study, we investigated the impact of VD₃ on the alveolar-capillary barrier in a co-culture model of alveolar epithelial cells and microvascular endothelial cells respectively in the individual cell types. After stimulation with bacterial LPS (lipopolysaccharide), gene expression of inflammatory cytokines, surfactant proteins, transport proteins, antimicrobial peptide, and doublecortin-like kinase 1 (DCLK1) were analyzed by real-time PCR, while corresponding proteins were evaluated by ELISA, immune-fluorescence, or Western blot. The effect of VD3 on the intracellular protein composition in H441 cells was analyzed by quantitative liquid chromatography-mass spectrometry-based proteomics. VD₃ effectively protected the alveolar-capillary barrier against LPS treatment, as indicated by TEER measurement and morphological assessment. VD₃ did not inhibit the IL-6 secretion by H441 and OEC but restricted the diffusion of IL-6 to the epithelial compartment. Further, VD₃ could significantly suppress the surfactant protein A expression induced in the co-culture system by LPS treatment. VD₃ induced high levels of the antimicrobial peptide LL-37, which counteracted effects by LPS and strengthened the barrier. Quantitative proteomics identified VD3-dependent protein abundance changes ranging from constitutional extracellular matrix components and surfactant-associated proteins to immune-regulatory molecules. DCLK1, as a newly described target molecule for VD₃, was prominently stimulated by VD₃ (10 nM) and seems to influence the alveolar-epithelial cell barrier and regeneration.

An inverse causal association between genetically predicted vitamin D and chronic obstructive pulmonary disease risk

Aim

Observational studies have reported that levels of vitamin D were associated with the incidence of chronic obstructive pulmonary disease (COPD), but the relationship between them may have been confounded in previous studies. In this study, we aimed to determine the relationship between the levels of 25-hydroxyvitamin D (25OHD) and the risk of COPD by two-sample Mendelian randomization (MR) analysis.

Methods

Summary statistics for 25OHD and COPD in this study were obtained from the EBI (n = 496,946) consortium and Finn (n = 187,754) consortium. MR was adopted to explore the effect of the genetically predicted levels of 25OHD on the risk of COPD. Based on three assumptions of MR analysis, inverse variance weighting was used as the main analysis. To make our results more robust and reliable, MR Egger’s intercept test, Cochran’s Q test, funnel plot, and “leave-one-out” sensitivity analysis were used to assess the potential pleiotropy and heterogeneity in this study. Then, colocalization analysis and MR Steiger approaches were used to estimate the possible directions of estimates between them. Finally, we analyzed the causal associations between the four core genes (DHCR7, GC, CYP2R1, and CYP24A1) of vitamin D and the levels of 25OHD or the risk of COPD.

Results

Our results showed that each 1 standard deviation (SD) increase in the genetically predicted 25OHD level was associated with a 57.2% lower relative risk of COPD [odds ratio (OR): 0.428, 95% Cl: 0.279–0.657, p = 1.041 × 10−4], and the above association was also verified by maximum likelihood (OR: 0.427, 95% Cl: 0.277–0.657, p = 1.084 × 10−4), MR–Egger (OR: 0.271, 95% CI: 0.176–0.416, p = 2.466 × 10−4), MR-PRESSO (OR: 0.428, 95% Cl: 0.281–0.652, p = 1.421 × 10−4) and MR-RAPS (OR: 0.457, 95% Cl: 0.293–0.712, p = 5.450 × 10−4). Furthermore, colocalization analyses (rs3829251, PP.H4 = 0.99) and MR Steiger (“TRUE”) also showed a reverse association between them. Besides, the core genes of vitamin D also showed similar results except for CYP24A1.

Conclusion

Our findings provide evidence for a reverse association between genetically predicted 25OHD levels and COPD risk. Taking measures to supplement 25OHD may help reduce the incidence of COPD.

Periodic breathing in clinically stable very preterm infants

OBJECTIVE

We aimed to investigate the frequency and severity of periodic breathing (PB) in clinically stable very preterm infants and identify infant and maternal factors associated with increased time spent and severity of PB in these infants.

METHOD

Thirty-eight infants (28-32 weeks gestational age) who were ≥3 days off noninvasive respiratory support, were studied for 2-3 h with a daytime sleep study at 31-36 weeks postmenstrual age. Percent total sleep time spent in PB (%TSTPB) and time spent with SpO₂ <90%, <80%, and cerebral oxygenation <55% during PB were calculated. Infant and maternal characteristics were correlated with %TSTPB and hypoxia during PB.

RESULTS

The majority of infants (92%) had at least one episode of PB and infants spent a median 9.1 [interquartile range: 1.2, 15.5] %TSTPB. 80%, 37%, and 37% of infants experienced SpO₂ <90%, <80% and cerebral oxygenation <55%, respectively, during PB. Shorter duration of respiratory support, multigravida, multiparity, and maternal vitamin D deficiency were associated with higher %TSTPB. Multigravida, shorter duration on respiratory support, apnea of prematurity, and resuscitation at birth were associated with hypoxia during PB.

CONCLUSIONS

The majority of very preterm infants exhibited PB when they were off respiratory support and considered clinically stable. The time spent in PB was very variable between infants and was associated with significant hypoxia in some infants. Fewer days spent on respiratory support was associated with both increased frequency and severity of PB. However, the potential contribution of PB to neurocognitive outcomes remains uncertain and warrants further investigations.

Does vitamin D level associate with pregnancy outcomes in Chinese women undergoing in vitro fertilization/intracytoplasmic sperm injection-embryo transfer? A retrospective cohort study

AIM

To explore the relationship between serum 25(OH)D level and pregnancy outcomes (clinical pregnancy rate [CPR] and live birth rate [LBR]) in Chinese women receiving in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI)-embryo transfer (ET) (IVF/ICSI-ET).

METHODS

A total of 612 patients included in the study were divided into four cohorts according to serum 25(OH)D with the threshold of 20 ng/ml, 25 ng/ml, 30 ng/ml, and retrospectively analyzed.

RESULTS

None of the baseline characteristics of participants was significantly different in the four cohorts except gravid status. The trend of 25(OH)D concentration was positively correlated with CPR and LBR. The younger (age: p < 0.001 both in CPR and LBR) women with primary infertility (infertility type: p = 0.004 in LBR) were more likely to get a better pregnancy outcome under the same 25(OH)D concentration stages. As shown on heatmap plots, CPR, and LBR were significantly increased for 25(OH)D concentrations above 30.00 ng/ml and women younger than 30 years old. The adjusted binary logistic regression and restricted cubic spline (RCS) showed that there existed a nonlinear positive correlation between 25(OH)D concentration and pregnancy outcome (CPR and LBR) (P_nonlinear  < 0.001, respectively). The women with a sufficient 25(OH)D concentration (30 ng/ml) had 1.07 (clinical pregnancy) and 1.05 (live birth) times higher successful birth outcomes compared to women with an insufficient 25(OH)D concentration (25 ng/ml). (OR_{25 ng/ml, ref = 30 ng/ml} [95% CI] = 0.935 [0.932-0.938] and 0.947 [0.945-0.950], p < 0.001, respectively).

CONCLUSION

In Chinese women receiving IVF/ICSI-ET, the serum level of 25(OH)D demonstrated a nonlinear positive correlation with pregnancy outcomes (CPR and LBR), with stronger correlations above 25 ng/ml and worse yields below 30 ng/ml. However, it could not yet be considered different in distinct ages.

The association of serum vitamin D level and neonatal respiratory distress syndrome

BACKGROUND

Neonatal respiratory distress syndrome (NRDS) is a critical disease in premature infants. Vitamin D plays an important role in promoting the development of fetal lung structure and the formation of pulmonary surfactants. This study aimed to investigate the correlation between the serum 25(OH)D₃ level in the cord blood of premature infants and the prognosis of NRDS.

METHODS

This retrospective study recruited 82 preterm infants (gestational age 28-36 weeks) diagnosed with NRDS as the NRDS group, and 82 non-NRDS preterm infants as the control group, respectively. The diagnostic efficiency of 25(OH)D₃ on NRDS was revealed by receiver operating characteristics curve (ROC) analysis. Enzyme linked immunosorbent assay (ELISA) was performed to evaluate the 25(OH)D₃ level in the serum of the cord blood in preterm neonates. The NRDS risk indicators were identified by the multivariate logistic regression analysis.

RESULTS

Cord blood 25(OH)D₃ levels were significantly lower in NRDS preterm infants than control group infants. 25(OH)D₃ levels in cord blood can be used to predict NRDS in preterm infants. In addition, 25(OH)D₃ levels in cord blood were positively correlated with Apgar score (1 min/5 min) and negatively correlated with oxygen support/CPAP duration in preterm infants with NRDS. 25(OH)D₃ in cord blood <57.69 nmol/L (24 ng/ml), gestational age <31 weeks, birth weight <1.86 kg, Apgar score (1 min) <7 and Apgar score (5 min) < 8 were independent risk factors for NRDS.

CONCLUSION

25(OH)D₃ level is an independent risk factor for NRDS in preterm infants.

Association between vitamin D level and respiratory distress syndrome: A systematic review and meta-analysis

BACKGROUND

Growing evidence suggests an association between the vitamin D levels and respiratory outcomes of preterm infants. The objective of this systematic review and meta-analysis was to explore whether premature neonates with a vitamin D deficiency have an increased risk of respiratory distress syndrome (RDS).

METHODS

We searched PubMed, EMBASE, and the Cochrane Library up through July 20, 2021. The search terms were 'premature infant', 'vitamin D', and 'respiratory distress syndrome'. We retrieved randomized controlled trials and cohort and case-control studies. For statistical analysis, we employed the random-effects model in Comprehensive Meta-Analysis Software ver. 3.3. We employed the Newcastle-Ottawa Scales for quality assessment of the included studies.

RESULTS

A total of 121 potentially relevant studies were found, of which 15 (12 cohort studies and 3 case-control studies) met the inclusion criteria; the studies included 2,051 preterm infants. We found significant associations between RDS development in such infants and vitamin D deficiency within 24 h of birth based on various criteria, thus vitamin D levels < 30 ng/mL (OR 3.478; 95% CI 1.817-6.659; p < 0.001), < 20 ng/mL (OR 4.549; 95% CI 3.007-6.881; p < 0.001), < 15 ng/mL (OR 17.267; 95% CI 1.084-275.112; p = 0.044), and < 10 ng/ml (OR 1.732; 95% CI 1.031-2.910; p = 0.038), and an even lower level of vitamin D (SMD = -0.656; 95% CI -1.029 to -0.283; p = 0.001).

CONCLUSION

Although the vitamin D deficiency definitions varied and different methods were used to measure vitamin D levels, vitamin D deficiency or lower levels of vitamin D within 24 h of birth were always associated with RDS development. Monitoring of neonatal vitamin D levels or the maintenance of adequate levels may reduce the risk of RDS.

Vitamin D supplementation and lower respiratory tract infection in infants: a nested case-control study

PURPOSE

To assess the association between vitamin D (VD) supplementation and the risk of lower respiratory tract infection (LRTI) among infants.

METHODS

This is a nested case-control study from an ongoing prospective birth cohort in Wuhan from 2013. Cases were subjects free of neonatal pneumonia but later developed LRTI during infancy, who were matched with five randomly selected controls by infant sex, birth year, and birth season. We included 190 cases and 950 controls in the final analysis. The primary outcome was the first LRTI incident and the exposure was VD supplementation from birth to the index endpoint. The association between VD supplementation and LRTI risk was assessed using the Cox proportional-hazards regression model.

RESULTS

Infants taking supplements had a 59% relative reduction in the hazard ratio of LRTI (HR = 0.41; 95% CI 0.26, 0.64) compared to those not supplemented. There was a linear relationship between LRTI risk and VD supplementation within range of 0-603 IU/day: for each 100 IU per day increment in VD supplementation, infants experienced a 21% lower risk of developing LRTI (adjusted HR: 0.79; 95% CI 0.71, 0.89). The linear relationship was stably observed in the sensitivity analyses as well.

CONCLUSIONS

VD supplementation was associated with the reduced risk of LRTI throughout infancy, and the optimal supplementation dose for infants may be beyond the current recommendation.

All trans-retinoic acid modulates hyperoxia-induced suppression of NF-kB-dependent Wnt signaling in alveolar A549 epithelial cells

INTRODUCTION

Despite recent advances in perinatal medicine, bronchopulmonary dysplasia (BPD) remains the most common complication of preterm birth. Inflammation, the main cause for BPD, results in arrested alveolarization. All trans-retinoic acid (ATRA), the active metabolite of Vitamin A, facilitates recovery from hyperoxia induced cell damage. The mechanisms involved in this response, and the genes activated, however, are poorly understood. In this study, we investigated the mechanisms of action of ATRA in human lung epithelial cells exposed to hyperoxia. We hypothesized that ATRA reduces hyperoxia-induced inflammatory responses in A549 alveolar epithelial cells.

METHODS

A549 cells were exposed to hyperoxia with or without treatment with ATRA, followed by RNA-seq analysis.

RESULTS

Transcriptomic analysis of A549 cells revealed ~2,000 differentially expressed genes with a higher than 2-fold change. Treatment of cells with ATRA alleviated some of the hyperoxia-induced changes, including Wnt signaling, cell adhesion and cytochrome P450 genes, partially through NF-κB signaling.

DISCUSSION/CONCLUSION

Our findings support the idea that ATRA supplementation may decrease hyperoxia-induced disruption of the neonatal respiratory epithelium and alleviate development of BPD.

Preterm Infants on Early Solid Foods and Vitamin D Status in the First Year of Life—A Secondary Outcome Analysis of a Randomized Controlled Trial

Preterm birth places infants at high risk for mineral and micronutrient deficiencies important for bone health. The aim of this study was to examine whether two timepoints for the introduction of solid foods in preterm infants have an impact on vitamin D status in the first year of life. This is a secondary outcome analysis of a prospective, randomized trial on very low birth weight (VLBW) infants, randomized to an early (10–12th week corrected age) or a late (16–18th week corrected age) complementary-feeding group. Vitamin D status was assessed by blood samples taken at 6 weeks, 6, and 12 months corrected age. In total, 177 infants were randomized (early group: n = 89, late group: n = 88). There was a tendency toward lower levels of serum 25-OH-vitamin D in the early group throughout the first year of life (p = not significant (n.s.)); no differences were detected in the other parameters. At 6 months corrected age, infants of the early group had a significantly higher incidence of vitamin D deficiency. The timepoint of the introduction of solid foods had no impact on the serum 25-OH-vitamin D levels and other parameters important for bone health but showed a tendency toward lower levels in the early-feeding group.

Moving bronchopulmonary dysplasia research from the bedside to the bench

Although advances in the respiratory management of extremely preterm infants have led to improvements in survival, this progress has not yet extended to a reduction in the incidence of bronchopulmonary dysplasia (BPD). BPD is a complex multifactorial condition that primarily occurs due to disturbances in the regulation of normal pulmonary airspace and vascular development. Preterm birth and exposure to invasive mechanical ventilation also compromises large airway development, leading to significant morbidity and mortality. Although both predisposing and protective genetic and environmental factors have been frequently described in the clinical literature, these findings have had limited impact on the development of effective therapeutic strategies. This gap is likely because the molecular pathways that underlie these observations are yet not fully understood, limiting the ability of researchers to identify novel treatments that can preserve normal lung development and/or enhance cellular repair mechanisms. In this review article, we will outline various well-established clinical observations while identifying key knowledge gaps that need to be filled with carefully designed preclinical experiments. We will address these issues by discussing controversial topics in the pathophysiology, the pathology, and the treatment of BPD, including an evaluation of existing animal models that have been used to answer important questions.

Local protocol helped to deliver vitamin D levels more accurately in preterm infants

AIM

This study retrospectively evaluated the effectiveness and safety of a local hospital protocol of vitamin D supplementation for preterm infants, which was modified in 2016.

METHODS

We focussed on 99 preterm infants born before 31 weeks of gestation and admitted to the neonatal intensive care unit at the Femme Mere Enfant Hospital, Bron, France, from 1 January to 31 December 2018. Calcium and urinary calcium were measured, and 25-hydroxy vitamin D (25(OH)D) levels were monitored monthly and supplementation was adjusted, with 50-120 nmol/L considered normal. The results are presented as medians and interquartile ranges.

RESULTS

The infants were enrolled at a gestational age of 28.0 [26.9-29.1] weeks and birth weight of 960 [800-1160] g. When they were discharged at 37.3 [35.2-39.8] weeks, the overall 25(OH)D level was 98 [79-140] nmol/L: 4% had low levels, 63% had normal levels and 33% had high levels. Vitamin D supplementation was withdrawn for 60% more than one month before discharge. Rickets or fractures were not reported.

CONCLUSION

The modified protocol limited underdosing and significant overdosing, but moderate hypervitaminosis D was still frequent. Urgent studies are needed to determine the optimal supplementation and clinical impact of 25(OH)D on comorbidities in preterm infants.

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.

Association between vitamin D deficiency at one month of age and bronchopulmonary dysplasia

Vitamin D deficiency is common and increases the likelihood of neonatal morbidities in preterm infants. This study assessed vitamin D levels at 1 month of age after 4 weeks of vitamin D supplementation and determined the association between vitamin D levels and neonatal morbidities.This retrospective study included preterm infants with birth weight <1500 g or gestational age <32 weeks born in our hospital between January 2018 and December 2019. They were administered 400 IU of oral vitamin D supplementation after birth according to our policy. The infants were then divided into sufficient (≥20 ng/mL) and deficient (<20 ng/mL) groups according to their serum vitamin D levels at 1 month of age.The vitamin D deficient and sufficient groups included 49 and 41 patients, respectively. The mean gestational age and birth weight. GHT in the vitamin D deficient group were 29.1 ± 2.1 weeks and 1216.1 ± 308.1 g, respectively, and 30.0 ± 1.7 weeks and 1387.6 ± 350.8 g, respectively, in the sufficient group. No significant differences were observed between the 2 groups in demographic and clinical outcomes except for bronchopulmonary dysplasia (BPD), which occurred significantly more often in the vitamin D-deficient group (odds ratio 2.21; 95% confidence interval, 1.85-2.78; P = .02).The results of our study suggest that vitamin D deficiency at 1 month of age is associated with BPD in preterm infants.

Relationship between bronchopulmonary dysplasia, long-term lung function, and vitamin D level at birth in preterm infants

BACKGROUND

We aimed to investigate the relationship between the level of serum 25 hydroxyvitamin D [25-(OH)D] at birth and the complications of bronchopulmonary dysplasia (BPD), as well as the long-term lung function of preterm infants.

METHODS

A total of 286 premature infants who were admitted to the neonatal ward of Haikou Maternal and Child Health Hospital from January 2018 to December 2020 and met the inclusion criteria were selected as the research objects. The level of serum 25(OH)D at birth was detected. The children were divided into a BPD group (79 cases) and a non-BPD group (207 cases). The case information and basic data of the children were recorded. The children were followed up 6 months after correcting the gestational age of 40 weeks, and their long-term lung function development was reported. Logistic regression analysis was used to evaluate the high-risk factors of BPD in preterm infants.

RESULTS

The 1- and 5-minute Apgar scores of preterm infants in the BPD group were significantly lower than those in the non-BPD group. Also, the combined neonatal pneumonia, neonatal asphyxia, hospital stay, and total oxygen therapy time in the BPD group were substantially higher than those in the non-BPD group. The mean value of serum 25-(OH)D at birth in the BPD group (33.7±15.1 nmol/L) was significantly lower than that in the non-BPD group (49.5±19.6 nmol/L). Compared with the non-BPD group, the respiratory rate (RR) in the BPD group increased significantly, while the tidal volume (VT), inspiratory to expiratory ratio (TI/TE), ratio of time to peak tidal expiratory flow to total expiratory time (TPEF/TE), and 25% tidal expiratory flow rate (TEF25%) decreased markedly (P<0.05). Total oxygen therapy time, neonatal pneumonia, neonatal asphyxia, and serum 25-(OH)D level at birth were identified as independent risk factors for BPD in preterm infants.

CONCLUSIONS

The level of serum 25-(OH)D in preterm infants at birth is closely related to the occurrence of BPD and long-term lung function damage, and is affected by multiple high-risk factors. This study provides a theoretical basis for the individualized treatment of preterm infants and the early prevention of BPD.

Association between Interleukin-6 and vitamin D serum levels in patients with obstructive sleep apnea syndrome and impact of long-term continuous positive airway pressure therapy on biomarker levels

OBJECTIVE

Hypoxia induces interleukin-6 (IL-6) production in obstructive sleep apnea syndrome (OSAS). Low serum 25 hydroxyvitamin D (25(OH)D) levels have been linked to OSAS susceptibility. Serum 25(OH)D levels have been negatively correlated with serum IL-6 levels in patients with chronic inflammation. No data exist to assess whether there is a correlation between 25(OH)D and IL-6 serum levels in OSAS, while the impact of continuous positive airway pressure (CPAP) therapy on IL-6 or 25(OH)D levels needs further investigation. We aimed to compare the serum 25(OH)D and IL-6 levels between OSAS patients and controls, examine a possible correlation between 25(OH)D and IL-6 levels and the changes of their concentrations after twelve months of CPAP therapy in OSAS patients.

METHODS

15 newly-diagnosed OSAS patients and 15 non-apneic controls were recruited. Serum IL-6 and 25(OH)D levels were measured in the study population at baseline and twelve months after CPAP initiation in OSAS patients.

RESULTS

IL-6 levels were elevated in OSAS patients than controls and were positively and negatively correlated with body mass index (BMI) and minimum oxyhemoglobin saturation (minSpO₂), respectively. Diabetes mellitus, BMI and minSpO₂ independently predicted IL-6 levels. No difference was found in 25(OH)D levels between groups. No correlation between IL-6 and 25(OH)D levels was detected. Effective CPAP therapy did not impact IL-6 or 25(OH)D levels after one year in OSAS patients.

CONCLUSIONS

No correlation between IL-6 and 25(OH)D levels was found. IL-6 levels were significantly elevated in OSAS patients than the controls and positively correlated with BMI, diabetes mellitus, and nocturnal hypoxemia.

Detection of Vitamin D Metabolites in Breast Milk: Perspectives and challenges for measurement by Liquid Chromatography Tandem-Mass Spectrometry

Breast milk is an emerging matrix for vitamin D assessment of breastfed infants and their mothers. It is considered a more reliable indicator of infant intake than the assessment of maternal circulating vitamin D. With the improved sensitivity of mass spectrometry-based technologies, this method principle has been the recent mainstay for the quantitation of various vitamin D metabolites in breast milk for population-based clinical trials. There are still several areas across the total testing process (pre-analytical, analytical and post-analytical) to be defined and harmonised to translate breast milk vitamin D measurement by liquid chromatography-tandem mass spectrometry (LC-MS/MS) from population-based research to routine clinical use and public health applications. Pre-analytically, the determination of the best form of vitamin D to measure in breast milk requires more evidence. Analytically, standardisation of the methods to allow for comparability of results is required. Post analytically, breast milk vitamin D decision limits are needed to turn the individual numerical outputs into clinically meaningful results. This review aims to synthesise the current evidence and utility of measurement of breast milk vitamin D by LC-MS/MS and to lead a future discussion on best practices to allow for its clinical utility beyond its current research-based use.

The Relationship between Vitamin D Levels and Clinical Outcomes of Neonatal Sepsis in Haji Adam Malik Hospital Medan, Indonesia

BACKGROUND: Vitamin D deficiency in neonates is associated with neonatal sepsis incidence. It is also significantly correlated to the increased risk in the outcomes of sepsis, such as mortality, length of hospital stay, and use of ventilatory support. AIM: The aim of the study is to observe the relationship between Vitamin D levels and clinical outcomes of sepsis in the neonatal unit. METHODS: An analytical cross-sectional study was conducted to neonates in neonatology Haji Adam Malik hospital from June 2019 to February 2020. A Chi-square test was carried out to observe the relationship between Vitamin D levels and sepsis outcomes, and a Mann-Whitney test was done to assess the significance between Vitamin D levels and length of hospital stay. RESULTS: Among 41 full-term and pre-term neonates, there were 75.6% (31/41) neonates with Vitamin D deficiency, while 24.4% (10/41) had normal Vitamin D levels and did not suffer from deficiency. The relationship of Vitamin D levels with mortality, use of ventilatory support, length of stay, and blood culture was p = 0.660 (95% confidence interval [CI] = 0.810–1.677), p = 0.013 (p < 0.05), p = 0.940 (median 21 days), and p =0.712 (95% CI = 0.623–1.353), respectively. CONCLUSION: Vitamin D deficiency had a significant relationship with ventilatory support requirement as one of the sepsis outcomes in neonates.

Role of vitamin D-vitamin D receptor signaling on hyperoxia-induced bronchopulmonary dysplasia in neonatal rats

BACKGROUND

Vitamin D exerts therapeutic effects on bronchopulmonary dysplasia (BPD), but its underlying mechanisms remain unclear. The present study was designed to investigate the effects of vitamin D on hyperoxia-induced BPD and elucidate the underlying mechanisms.

METHODS

Neonatal rats were exposed to either room air (control) or 75% O₂ (hyperoxia) and intraperitoneally injected with vitamin D3. After 14 days, a histopathological examination was performed in the lungs of rats. Serum 25-hydroxyvitamin D (25OHD) was measured by liquid chromatography-tandom mass spectrometry (LC-MS)/MS. Interleukin 1 beta (IL-1β) and interferon gamma (IFN-γ) were measured by specific enzyme-linked immunosorbent assays. The messenger RNA and protein levels of vitamin D receptor (VDR), vascular endothelial growth factor (VEGF), VEGF receptor 2 (VEGFR2), and hypoxia-inducible factor 1α (HIF-1α) were determined by real-time quantitative reverse transcription polymerase chain reaction and immunoblot analysis, respectively.

RESULTS

Treatment with vitamin D3 increased serum 25OHD and upregulated VDR in lung tissues with or without hyperoxia. In addition, treatment with vitamin D3 attenuated alveolar simplification, increased VEGF and VEGFR2, and protected alveolar simplification induced by hyperoxia. Furthermore, treatment with vitamin D3 resulted in a decrease of IL-1β and IFN-γ and an increase of HIF-1α in lung tissues under hyperoxia conditions.

CONCLUSION

Vitamin D exerts protective effects on hyperoxia-induced BPD in neonatal rats by regulating vitamin D-VDR signaling pathways.

VitA or VitD ameliorates bronchopulmonary dysplasia by regulating the balance between M1 and M2 macrophages

PURPOSE

To investigate the therapeutic effects of vitamin A (VitA) or vitamin D (VitD) against bronchopulmonary dysplasia (BPD) and the underlying mechanism from the perspective of macrophage polarization.

METHODS

A BPD model was established on rats. Hematoxylin and eosin staining was used to evaluate the pathological state of lung tissues. The expression of CD68 was determined by immunohistochemistry assay. The infiltration of M1 and M2 macrophages was marked by immunofluorescence. The expression levels of tumor necrosis factor (TNF)-α, interleukin (IL)-10, nitric oxide synthase (NOS), and arginase-1 (Arg-1) were evaluated by quantitative reverse transcription polymerase chain reaction assay, and the ratio of M1/M2 in the bronchoalveolar lavage fluid was determined by flow cytometry.

RESULTS

Disordered alveolar structure in the lung tissue, thickened alveolar septa, and infiltration of inflammatory cells around the alveolar cavity and pulmonary septa were observed in lipopolysaccharide (LPS)-treated rats. On day 21 post-natal (PN21), the pathological state was aggravated, alveolar simplification was observed, and the expression level of CD68 in the lung tissues was significantly elevated, and these results were dramatically alleviated in the VitA, VitD, and VitA+VitD groups. However, no significant synergistic effect was observed between VitA+VitD and VitA or VitD groups. After the administration with VitA or VitD, IL-10 and Arg-1 were up-regulated on PN10. TNF-α and NOS were up-regulated on PN21. The ratio of macrophage polarization and M2 macrophages increased considerably after the stimulation with LPS, and this result was significantly reversed by VitA or VitD. A significant difference was observed on the effect of different dosages of VitA or VitD on macrophage polarization, among which moderate dosages of VitA or VitD exerted the most significant influence on macrophage polarization.

CONCLUSION

The BPD-linked pulmonary injury stimulated by LPS can be ameliorated by the introduction of VitA or VitD.

The potential effects of vitamin D deficiency on respiratory distress syndrome among preterm infants

INTRODUCTION

Vitamin D deficiency is one of the most commonly deficient vitamins worldwide. Preterm infants usually suffer from different complications. However, the relationship between vitamin D levels and RDS prevalence has been emerging in the last few years.

AIM

This study aimed to assess the severity of respiratory distress syndrome in preterm infants who are ≤34 weeks GA, with a birth weight of ≤2 kg, and its relation to their serum blood level of vitamin D.

MATERIALS AND METHODS

This is a multicenter study conducted at Neonatal Intensive Care Unit (NICU) at King Fahad Medical City (KFMC), Riyadh, Saudi Arabia, and Maternity and Children Hospital (MCH), Qassim, Saudi Arabia. We observed prospectively all preterm babies who were ≤34 weeks GA with 25-hydroxyvitamin D (25OHD) serum level ≤30 ng/ml at 24 h of life or less. Included infants were divided into 2 groups; infants with 25-hydroxyvitamin D level of ≤30 ng/ml were the deficient group and those with >30 ng/ml were considered in the normal group.

RESULTS

174 preterm infants were included in this study with an average gestational age of 30.2 ± 2.7 weeks. The mean vitamin D level was 30.5 (SD 19.5). Vitamin D deficiency was detected among 99 infants (56.9%). Of the deficient infants, 26.3% were severe, 42.4% moderate and 31.3% were mild. Pneumothorax was 2.9% and mortality rates were recorded among 14 cases (8%).

CONCLUSION

Vitamin D deficiency was widely prevalent among preterm neonates. Pneumothorax, surfactant doses, oxygen, and mechanical ventilation requirements were statistically significant at vitamin D deficiency.

Association of vitamin D status at birth with pulmonary disease morbidity in very preterm infants

OBJECTIVE

We aimed to assess whether serum 25-hydroxyvitamin D (25(OH)D) levels at birth are associated with pulmonary disease morbidities in very preterm infants.

METHODS

This prospective cohort analysis included 93 infants born before 32 weeks of gestation in the Second Xiangya Hospital of Central South University between March 2016 and February 2017. Participants were classified into three groups according to their 25(OH)D levels at birth. The groups were compared in terms of demographic variables and pulmonary disease morbidities.

RESULTS

The mean serum 25(OH)D level at birth was 35.7 ± 19.1 nmol/L, and 38 (40.9%), 31 (33.3%), and 24 (25.8%) infants had 25(OH)D levels of less than 25 nmol/L, 25-50 nmol/L, and more than or equal to 50 nmol/L, respectively. There was a statistically significant difference in neonatal respiratory distress syndrome (RDS) rates among the three groups (43.6% vs. 35.9% vs. 20.5%, p = .029). The rates of bronchopulmonary dysplasia, apnea, respiratory failure, persistent pulmonary hypertension, and pulmonary hemorrhage did not differ significantly among the groups. Logistic analysis, adjusted for gestational age and birth weight, showed that a low serum 25(OH)D level (<50 nmol/L) was a risk factor for RDS (odds ratio, 0.195; p = .017).

CONCLUSION

There was a high prevalence of low 25(OH)D levels (<50 nmol/L) and an association between vitamin D status and RDS in very preterm infants. However, more research on this association is required.

Contribution of comorbidities to obesity-related asthma in children

Children with obesity are at increased risk for developing asthma that is difficult to control. A complicating factor to asthma management among these children is likely the commonplace co-morbidities that also result from obesity. We discuss three common obesity-related comorbidities which appear to complicate the effective management of asthma, including hypovitaminosis D, obstructive sleep apnea and gastro-esophageal reflux. Each conditions requires more research to understand their effects on asthma management.

Vitamin D improves pulmonary function in a rat model for congenital diaphragmatic hernia

A congenital diaphragmatic hernia (CDH) is an anomaly caused by defects in the diaphragm; the resulting limited thorax cavity in turn restricts lung growth (pulmonary hypoplasia). This condition is related to pulmonary hypertension. Despite advances in neonatal CDH therapy, the mortality for severe pulmonary hypoplasia remains high. Therefore, it is essential to establish prenatal therapeutic interventions. Vitamin D was reported to have beneficial effects on adult pulmonary hypertension. This study aims to evaluate the efficacy of prenatal vitamin D administration for CDH. First, serum 25-hydroxyvitamin D [25(OH)D] levels in umbilical cord blood were evaluated among CDH newborns. Second, Sprague Dawley rat CDH models were exposed to nitrofen on embryo day 9 (E9). Randomly selected rats in the nitrofen-treated group were infused with calcitriol from E9 to E21. Samples from CDH pups diagnosed after birth were used for lung weight measurements, blood gas analysis, and immunohistochemical analysis. Third, microarray analysis was performed to examine the effect of vitamin D on gene expression profiles in CDH pulmonary arterial tissues. Serum 25(OH)D levels in the umbilical cord blood of newborns who did not survive were significantly lower than those who were successfully discharged. Prenatal vitamin D showed no significant effect on CDH incidence or lung weight but attenuated alveolarization and pulmonary artery remodeling accompanied the improved blood gas parameters. Vitamin D inhibited several gene expression pathways in the pulmonary arteries of CDH rats. Our results suggest that prenatal vitamin D administration attenuates pulmonary vascular remodeling by influencing several gene pathways in CDH.

Composition and origin of lung fluid proteome in premature infants and relationship to respiratory outcome

Background

Infants born at extremely low gestational age are at high risk for bronchopulmonary dysplasia and continuing lung disease. There are no early clinical biomarkers for pulmonary outcome and limited therapeutic interventions.

Objectives

We performed global proteomics of premature infant tracheal aspirate (TA) and plasma to determine the composition and source of lung fluid proteins and to identify potential biomarkers of respiratory outcome.

Methods

TA samples were collected from intubated infants in the TOLSURF cohort before and after nitric oxide treatment, and plasma was collected from NO CLD infants. Protein abundance was assayed by HPLC/tandem mass spectrometry and Protein Prospector software. mRNA abundance in mid-gestation fetal lung was assessed by RNA sequencing. Pulmonary morbidity was defined as a need for ventilatory support at term and during the first year.

Results

Abundant TA proteins included albumin, hemoglobin, and actin-related proteins. 96 of 137 detected plasma proteins were present in TA (r = 0.69, p<0.00001). Based on lung RNAseq data, ~88% of detected TA proteins in injured infant lung are derived at least in part from lung epithelium with overrepresentation in categories of cell membrane/secretion and stress/inflammation. Comparing 37 infants at study enrollment (7–14 days) who did or did not develop persistent pulmonary morbidity, candidate biomarkers of both lung (eg., annexin A5) and plasma (eg., vitamin D-binding protein) origin were identified. Notably, levels of free hemoglobin were 2.9-fold (p = 0.03) higher in infants with pulmonary morbidity. In time course studies, hemoglobin decreased markedly in most infants after enrollment coincident with initiation of inhaled nitric oxide treatment.

Conclusions

We conclude that both lung epithelium and plasma contribute to the lung fluid proteome in premature infants with lung injury. Early postnatal elevation of free hemoglobin and heme, which are both pro-oxidants, may contribute to persistent lung disease by depleting nitric oxide and increasing oxidative/nitrative stress.

Single nucleotide vitamin D receptor polymorphisms (FokI, BsmI, ApaI, and TaqI) in the pathogenesis of prematurity complications

The vitamin D receptor (VDR), coded by the VDR gene, plays a pivotal role in executing cellular functions when bound by the active form of vitamin D. Gene polymorphisms in this receptor have been increasingly associated with a heightened state of vulnerability to certain diseases. However, limited data is available concerning the role of VDR gene polymorphisms in preterm infant complications. In 114 premature infants (< 32 weeks gestation) we analyze four single nucleotide VDR polymorphisms (rs2228570 (FokI), rs1544410 (BsmI), rs797532 (ApaI), rs731236 (TaqI)) for their association with respiratory distress syndrome (RDS), intraventricular hemorrhage (IVH), bronchopulmonary dysplasia (BPD), necrotizing enterocolitis (NEC) and retinopathy of prematurity (ROP). The results show that BPD was almost four times more likely in infants with the genotype CC of ApaI (rs7975232) (OR 3.845; p = 0.038). While both BPD and NEC were 2.1 times more likely to occur in preterm infants with the allele C of ApaI (rs7975232) (respectively: OR 2.111 and OR 2.129, p < 0.05). The ApaI VDR polymorphism appears to influence incidence of BPD and NEC in preterm infants. Considering VDR polymorphisms in future genetic investigations, in preterm complications, may prove clinically relevant.

Vitamin D Metabolism Is Dysregulated in Asthma and Chronic Obstructive Pulmonary Disease

Rationale: Vitamin D deficiency is common in patients with asthma and chronic obstructive pulmonary disease (COPD). Low 25-hydroxyvitamin D (25[OH]D) levels may represent a cause or a consequence of these conditions.Objectives: To determine whether vitamin D metabolism is altered in asthma or COPD.Methods: We conducted a longitudinal study in 186 adults to determine whether the 25(OH)D response to six oral doses of 3 mg vitamin D₃, administered over 1 year, differed between those with asthma or COPD versus control subjects. Serum concentrations of vitamin D₃, 25(OH)D₃, and 1α,25-dihydroxyvitamin D₃ (1α,25[OH]₂D₃) were determined presupplementation and postsupplementation in 93 adults with asthma, COPD, or neither condition, and metabolite-to-parent compound molar ratios were compared between groups to estimate hydroxylase activity. Additionally, we analyzed 14 datasets to compare expression of 1α,25(OH)₂D₃-inducible gene expression signatures in clinical samples taken from adults with asthma or COPD versus control subjects.Measurements and Main Results: The mean postsupplementation 25(OH)D increase in participants with asthma (20.9 nmol/L) and COPD (21.5 nmol/L) was lower than in control subjects (39.8 nmol/L; P = 0.001). Compared with control subjects, patients with asthma and COPD had lower molar ratios of 25(OH)D₃-to-vitamin D₃ and higher molar ratios of 1α,25(OH)₂D₃-to-25(OH)D₃ both presupplementation and postsupplementation (P ≤ 0.005). Intergroup differences in 1α,25(OH)₂D₃-inducible gene expression signatures were modest and variable if statistically significant.Conclusions: Attenuation of the 25(OH)D response to vitamin D supplementation in asthma and COPD associated with reduced molar ratios of 25(OH)D₃-to-vitamin D₃ and increased molar ratios of 1α,25(OH)₂D₃-to-25(OH)D₃ in serum, suggesting that vitamin D metabolism is dysregulated in these conditions.

Serum vitamin D levels in patients with obstructive sleep apnea syndrome and level changes after continuous positive airway pressure therapy

PURPOSE

Patients with obstructive sleep apnea syndrome (OSAS) have been found to exhibit lower serum vitamin D levels, even when the control groups are matched for confounding conditions. However, contradictory studies are also present. This study aimed to compare serum 25-hydroxyvitamin D (25(OH)D) levels between adult patients with OSAS and non-apneic controls and to evaluate the changes in 25(OH)D levels after 3 and 12 months of continuous positive airway pressure (CPAP) therapy.

METHODS

The study was comprised of 30 patients with OSAS and 30 controls. Serum 25(OH)D levels were determined at baseline and after 3 and 12 months of CPAP therapy in all patients with OSAS. For analysis, patients with OSAS were divided into subgroups by adherence, with adherence defined as CPAP usage for > 4 h per night on at least 70% of nights.

RESULTS

The 25(OH)D levels were not significantly different between OSAS and control groups at baseline. 25(OH)D levels did not change after 3 and 12 months of CPAP therapy. Patients who were CPAP-adherent showed less reduction in 25(OH)D levels compared with non-adherent ones (21.18 ± 9.3 vs. 12.13 ± 3.8 ng/mL, p = 0.022) after 1 year. The 25(OH)D levels were significantly correlated with higher daily CPAP usage at 3 and 12 months. Mean daily CPAP usage was a significant predictor of serum 25(OH)D levels at 12 months.

CONCLUSIONS

Patients with OSAS who demonstrated good CPAP adherence showed significantly higher 25(OH)D levels after 1 year compared with those not adequately using CPAP. Long-term good CPAP adherence and highly daily CPAP usage positively affected 25(OH)D levels in patients with OSAS.