Effects of early vitamin D supplementation on the prevention of bronchopulmonary dysplasia in preterm 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.

Blocking IL-17a Signaling Decreases Lung Inflammation and Improves Alveolarization in Experimental Bronchopulmonary Dysplasia

Bronchopulmonary dysplasia (BPD) is the most common chronic lung disease of preterm infants that is associated with life-long morbidities. Inflammatory insults contribute to BPD pathogenesis. Although the proinflammatory cytokine, IL-17a, plays a role in various neonatal inflammatory disorders, its role in BPD pathogenesis is unclear. To test the hypothesis that blocking IL-17a signaling decreases lipopolysaccharide (LPS)-mediated experimental BPD in neonatal mice, wild-type mice were injected intraperitoneally with phosphate-buffered saline or LPS during the saccular lung developmental phase. Pulmonary IL-17a expression was determined by enzyme-linked immunosorbent assay and by flow cytometry. LPS-injected mice had higher pulmonary IL-17a protein levels and IL-17a+ and IL-22+ cells. γδ T cells, followed by non-T lymphoid cells, were the primary producers of IL-17a. Wild-type mice were then injected intraperitoneally with isotype antibody (Ab) or IL-17a Ab, while they were treated with phosphate-buffered saline or LPS, followed by quantification of lung inflammatory markers, alveolarization, vascularization, cell proliferation, and apoptosis. LPS-mediated alveolar simplification, apoptosis, and cell proliferation inhibition were significantly greater in mice treated with isotype Ab than in those treated with IL-17a Ab. Furthermore, STAT1 activation and IL-6 levels were significantly greater in LPS-exposed mice treated with isotype Ab than in those treated with IL-17a Ab. The study results indicate that blocking IL-17a signaling decreases LPS-mediated experimental BPD.

Endoplasmic Reticulum Stress in Bronchopulmonary Dysplasia: Contributor or Consequence?

Bronchopulmonary dysplasia (BPD) is the most common complication of prematurity. Oxidative stress (OS) and inflammation are the major contributors to BPD. Despite aggressive treatments, BPD prevalence remains unchanged, which underscores the urgent need to explore more potential therapies. The endoplasmic reticulum (ER) plays crucial roles in surfactant and protein synthesis, assisting mitochondrial function, and maintaining metabolic homeostasis. Under OS, disturbed metabolism and protein folding transform the ER structure to refold proteins and help degrade non-essential proteins to resume cell homeostasis. When OS becomes excessive, the endogenous chaperone will leave the three ER stress sensors to allow subsequent changes, including cell death and senescence, impairing the growth potential of organs. The contributing role of ER stress in BPD is confirmed by reproducing the BPD phenotype in rat pups by ER stress inducers. Although chemical chaperones attenuate BPD, ER stress is still associated with cellular senescence. N-acetyl-lysyltyrosylcysteine amide (KYC) is a myeloperoxidase inhibitor that attenuates ER stress and senescence as a systems pharmacology agent. In this review, we describe the role of ER stress in BPD and discuss the therapeutic potentials of chemical chaperones and KYC, highlighting their promising role in future therapeutic interventions.

Effects of vitamin D supplementation on serum 25(OH)D3 levels and neurobehavioral development in premature infants after birth

This study explored the factors influencing serum 25(OH)D3 levels and the effects of Vitamin D deficiency (VDD) and VD supplementation on 25(OH)D3 levels and neuropsychobehavioral development in premature infants, to provide a theoretical basis for improving their prognosis. Physical examination, neuropsychobehavioral development and serum 25(OH)D3 levels were assessed regularly in 158 preterm infants supplemented with VD formulation. 25(OH)D3 levels were analyzed at 3, 6, 9, 12, and 18 months after birth. The Gesell neuropsychological development test was conducted at 6, 9, 12, and 18 months after birth to obtain the developmental quotient (DQ). Based on the serum 25(OH)D3 levels at 42 days of age, the infants were divided into VDD and non-VDD groups. Preterm infants in the VDD group were supplemented with more VD until their 25(OH)D3 levels were normal, and were divided into sustained VDD (SVDD) and corrected VDD (CVDD) groups according to serum 25(OH)D3 levels at 3 months of age. Appropriate statistical methods were chosen to compare differences in 25(OH)D3 and DQ between or among different groups, screen for the factors influencing 25(OH)D3 levels in preterm infants at 42 days of age, and analyze the relationship between 25(OH)D3 and DQ. The 25(OH)D3 levels of preterm infants at 42 days of age were positively correlated with VD supplementation during pregnancy, and before 42 days after birth (P < 0.05). The 25(OH)D3 levels in preterm infants at 42 days and 3 months of age were positively correlated with the DQ levels at 6, 9, 12, and 18 months of age (P < 0.05). The DQ level in the VDD group, especially SVDD group, was lower than that in CVDD and non-VDD groups at the same time point (P < 0.05). This research thus demonstrates that VD supplementations during pregnancy and after birth is a major factor affecting 25(OH)D3 levels in premature infants. Early VDD and SVDD can affect their neuropsychobehavioral development, and effective VD supplementation can gradually correct VDD and mitigate this influence.

Fetal origin of bronchopulmonary dysplasia: contribution of intrauterine inflammation

Bronchopulmonary dysplasia (BPD) is a common chronic lung disease in infants and the most frequent adverse outcome of premature birth, despite major efforts to minimize injury. It is thought to result from aberrant repair response triggered by either prenatal or recurrent postnatal injury to the lungs during development. Intrauterine inflammation is an important risk factor for prenatal lung injury, which is also increasingly linked to BPD. However, the specific mechanisms remain unclear. This review summarizes clinical and animal research linking intrauterine inflammation to BPD. We assess how intrauterine inflammation affects lung alveolarization and vascular development. In addition, we discuss prenatal therapeutic strategies targeting intrauterine inflammation to prevent or treat BPD.

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.

Nutritional Needs of the Infant with Bronchopulmonary Dysplasia

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

Correlation between tear levels of vascular endothelial growth factor and vitamin D at retinopathy of prematurity stages in preterm infants

Deregulation of vascular endothelial growth factor (VEGF) levels leads to retinopathy of prematurity (ROP). Vitamin D (VIT-D) is known to regulate VEGF in an oxygen dependent manner. The purpose of this study was to correlate tear levels of VEGF and VIT-D with different ROP stages in preterm infants. In this prospective cross-sectional study, we enrolled 104 pre-term infants. They were grouped into: Group-1 (Classical ROP) and Group-2 (Aggressive ROP), which were further subdivided into Group-1A (progressing), Group-1B (regressing), Group-2A (pre-treatment), and Group-2B (post-treatment). Tear VEGF and VIT-D levels and their association with different ROP stages were assessed. Stage 1 and stage 2 had higher whereas stage 3 had lower VEGF levels in Group-1B compared to Group-1A. Stage 1 and stage 3 showed higher levels of VIT-D with no difference in stage 2 in Group-1B compared to Group-1A., Group-2B showed higher VEGF and lower VIT-D levels compared to Group-2A. Presence of a positive correlation at an early stage (stage 1) of ROP and a negative correlation at a more advanced stage (stage 3) of ROP with VIT-D and VEGF implies stage-specific distinct signaling crosstalk. These findings suggest that VIT-D supplementation may have the potential to modify the course and outcome of ROP.

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.

Inhaled nitric oxide in premature infants for preventing bronchopulmonary dysplasia: a meta-analysis

BACKGROUND

The effectiveness of nitric oxide (NO) in reducing the risk of bronchopulmonary dysplasia (BPD) remains debatable. In this study, we performed a meta-analysis to guide clinical decision-making regarding the significance of inhaled NO (iNO) on the potential occurrence and outcomes of BPD in premature infants.

METHODS

Data from clinical randomized controlled trials (RCTs) published in PubMed, Embase, Cochrane Library, Wanfang, China National Knowledge Infrastructure (CNKI) and Chinese Scientific Journal Database VIP databases for premature infants were searched from inception to March 2022. Review Manager 5.3 statistical software was used for heterogeneity analysis.

RESULTS

Of the 905 studies retrieved, 11 RCTs met the screening criteria of this study. Our analysis showed that the iNO group was associated with a significantly lower incidence of BPD than the control group (relative risk [RR] = 0.91, 95% confidence interval (CI) 0.85-0.97, P = 0.006). We also observed no significant difference in the incidence of BPD between the two groups at the initial dose of 5 ppm (ppm) (P = 0.09) but those treated with 10 ppm iNO had a significantly lower incidence of BPD (RR = 0.90, 95%CI 0.81-0.99, P = 0.03). However, it should be noted that although the iNO group had an increased risk for necrotizing enterocolitis (NEC) (RR = 1.33, 95%CI 1.04-1.71, P = 0.03), cases treated with an initial dose of 10 ppm revealed no significant difference in the incidence of NEC compared with the control group (P = 0.41), while those treated with an initial dosage of 5 ppm of iNO had a significantly greater NEC rates than the control group (RR = 1.41, 95%CI 1.03-1.91, P = 0.03). Further, we observed no statistically significant differences in the incidence of in-hospital mortality, intraventricular hemorrhage (IVH) (Grade 3/4) or periventricular leukomalacia (PVL) and pulmonary hemorrhage (PH) between the two treatment groups.

CONCLUSIONS

This meta-analysis of RCTs showed that iNO at an initial dosage of 10 ppm seemed more effective in reducing the risk of BPD than conventional treatment and iNO at an initial dosage of 5 ppm in preterm infants at a gestational age of ≤34 weeks who required respiratory support. However, the incidence of in-hospital mortality and adverse events between the overall iNO group and Control were similar.

Prematurity and BPD: what general pediatricians should know

More and more very low birth weight (VLBW) infants around the world survive nowadays, with consequently larger numbers of children developing prematurity-related morbidities, especially bronchopulmonary dysplasia (BPD). BPD is a multifactorial disease and its rising incidence in recent years means that general pediatricians are much more likely to encounter a child born extremely preterm, possibly with BPD, in their clinical practice. Short- and long-term sequelae in VLBW patients may affect not only pulmonary function (principally characterized by an obstructive pattern), but also other aspect including the neurological (neurodevelopmental and neuropsychiatric disorders), the sensorial (earing and visual impairment), the cardiological (systemic and pulmonary hypertension, reduced exercise tolerance and ischemic heart disease in adult age), nutritional (feeding difficulties and nutritional deficits), and auxological (extrauterine growth restriction). For the most premature infants at least, a multidisciplinary follow-up is warranted after discharge from the neonatal intensive care unit in order to optimize their respiratory and neurocognitive potential, and prevent respiratory infections, nutritional deficiencies or cardiovascular impairments.  Conclusion: The aim of this review is to summarize the main characteristics of preterm and BPD infants, providing the general pediatrician with practical information regarding these patients' multidisciplinary complex follow-up. We explore the current evidence on respiratory outcomes and their management that actually does not have a definitive available option. We also discuss the available investigations, treatments, and strategies for prevention and prophylaxis to improve the non-respiratory outcomes and the quality of life for these children and their families, a critical aspect not always considered. This comprehensive approach, added to the increased needs of a VLBW subjects, is obviously related to very high health-related costs that should be beared in mind. What is Known: • Every day, a general pediatrician is more likely to encounter a former very low birth weight infant. • Very low birth weight and prematurity are frequently related not only with worse respiratory outcomes, but also with neurological, sensorial, cardiovascular, renal, and nutritional issues. What is New: • This review provides to the general pediatrician a comprehensive approach for the follow-up of former premature very low birth weight children, with information to improve the quality of life of this special population.

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.