Maternal/neonatal vitamin D deficiency: a new risk factor for necrotizing enterocolitis in preterm infants?

A Modern Look at the Development of Intrauterine Pneumonia in Premature Newborns: Literature Review

Infectious diseases such as malaria, pneumonia, diarrhea and preventable neonatal diseases are common causes of death in children. Globally, neonatal mortality is 44% (2.9 million) annually, with up to 50% of babies dying within the first day of life. Pneumonia kills between 750000 and 1.2 million infants in the neonatal period each year in developing countries. Premature birth, pneumonia, and labor complications are common causes of neonatal mortality. The objective of the study is to present the general characteristics of congenital pneumonia, vitamin D deficiency and micronutrient deficiencies in premature infants. To date, numerous studies confirm the relationship between the inadequate supply of the body with macro- and microelements and the development of diseases of varying severity, including metabolic disorders. Based on this, primary screening, aimed at identifying metabolic disorders of macro- and microelements and further drug correction, should become the main concept for the management of patients in modern times.

Impact of maternal factors, environmental factors, and race on necrotizing enterocolitis

Necrotizing enterocolitis (NEC) is a complex disease with a multifactorial etiology. As the leading cause of intestinal morbidity and mortality among premature infants, many resources are being dedicated to neonatal care and molecular targets in the newborn intestine. However, NEC is heavily influenced by maternal and perinatal factors as well. Given its nature, preventive approaches to NEC are more likely to improve outcomes than new treatment strategies. Therefore, this review focuses on maternal, environmental, and racial factors associated with the development of NEC, with an emphasis on those that may be modifiable to decrease the incidence of the disease.

Vitamin D and calcium intakes in general pediatric populations: A French expert consensus paper

OBJECTIVES

Nutritional vitamin D supplements are often used in general pediatrics. Here, the aim is to address vitamin D supplementation and calcium nutritional intakes in newborns, infants, children, and adolescents to prevent vitamin D deficiency and rickets in general populations.

STUDY DESIGN

We formulated clinical questions relating to the following categories: the Patient (or Population) to whom the recommendation will apply; the Intervention being considered; the Comparison (which may be "no action," placebo, or an alternative intervention); and the Outcomes affected by the intervention (PICO). These PICO elements were arranged into the questions to be addressed in the literature searches. Each PICO question then formed the basis for a statement. The population covered consisted of children aged between 0 and 18 years and premature babies hospitalized in neonatology. Two groups were assembled: a core working group and a voting panel from different scientific pediatric committees from the French Society of Pediatrics and national scientific societies.

RESULTS

We present here 35 clinical practice points (CPPs) for the use of native vitamin D therapy (ergocalciferol, vitamin D2 and cholecalciferol, vitamin D3) and calcium nutritional intakes in general pediatric populations.

CONCLUSION

This consensus document was developed to provide guidance to health care professionals on the use of nutritional vitamin D and dietary modalities to achieve the recommended calcium intakes in general pediatric populations. These CPPs will be revised periodically. Research recommendations to study key vitamin D outcome measures in children are also suggested.

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.

Risk factors for necrotizing enterocolitis in neonates: A meta-analysis

OBJECTIVE

The objective is to identify the risk factors for necrotizing enterocolitis (NEC) in neonates by a meta-analysis, and to provide a reference for the prevention of NEC.

METHODS

The databases, including Chinese Biomedical Literature Datebase, China National Knowledge Infrastructure, Wanfang database, and Weipu Periodical database, PubMed, Web of Science, Embase, Cochrane Library, were searched for studies on the risk factors for NEC in neonates. The meta-analysis was carried out with the aid of Stata software.

RESULTS

A total of 52 studies were included, with 48 case-control studies and 4 cohort studies. There were 166,580 neonates in total, with 33,522 neonates in the case group and 133,058 neonates in the control group. The meta-analysis showed that gestational diabetes (OR = 3.62, 95% CI:1.77-7.41), premature rupture of membranes (OR = 3.81, 95% CI:1.16-12.52), low birth weight (OR = 3.00, 95% CI:2.26-3.97), small for gestational age (OR = 1.85, 95% CI:1.15-2.97), septicemia (OR = 4.34, 95% CI:3.06-6.15), blood transfusion (OR = 3.08, 95% CI:2.16-4.38), congenital heart disease (OR = 2.73, 95% CI:1.10-6.78), respiratory distress syndrome (OR = 2.12, 95% CI:1.24-3.63), premature birth (OR = 5.63, 95% CI:2.91-10.92), pneumonia (OR = 4.07, 95% CI:2.84-5.82) were risk factors for NEC in neonates. Breastfeeding (OR = 0.37, 95% CI:0.23-0.59), take probiotics (OR = 0.30, 95% CI:0.22-0.40), prenatal use of glucocorticoids (OR = 0.39, 95% CI:0.30-0.50), Hyperbilirubinemia (OR = 0.28, 95% CI:0.09-0.86) were protective factors for NEC in neonates.

CONCLUSIONS

Gestational diabetes, premature rupture of membranes, low birth weight, small for gestational age, septicemia, blood transfusion, congenital heart disease, respiratory distress syndrome, premature birth, and pneumonia may increase the risk of NEC in neonates. Breastfeeding, taking probiotics, prenatal use of glucocorticoids, and Hyperbilirubinemia may reduce the risk of NEC in neonates.

Intestinal Regulatory T Cells

Mucosal surfaces are distinctive sites exposed to environmental, dietary, and microbial antigens. Particularly in the gut, the host continuously actively adapts via complex interactions between the microbiota and dietary compounds and immune and other tissue cells. Regulatory T cells (Tregs) are critical for tuning the intestinal immune response to self- and non-self-antigens in the intestine. Its importance in intestinal homeostasis is illustrated by the onset of overt inflammation caused by deficiency in Treg generation, function, or stability in the gut. A substantial imbalance in Tregs has been observed in intestinal tissue during pathogenic conditions, when a tightly regulated and equilibrated system becomes dysregulated and leads to unimpeded and chronic immune responses. In this chapter, we compile and critically discuss the current knowledge on the key factors that promote Treg-mediated tolerance in the gut, such as those involved in intestinal Treg differentiation, specificity and suppressive function, and their immunophenotype during health and disease. We also discuss the current state of knowledge on Treg dysregulation in human intestine during pathological states such as inflammatory bowel disease (IBD), necrotizing enterocolitis (NEC), graft-versus-host disease (GVHD), and colorectal cancer (CRC), and how that knowledge is guiding development of Treg-targeted therapies to treat or prevent intestinal disorders.

Correlation between Fecal Calprotectin Levels in Meconium and Vitamin D Levels in Cord Blood: Association with Intestinal Distress

We aimed to investigate the correlation between vitamin D status in cord blood and fecal calprotectin concentrations in meconium, and also find their association with intestinal distress symptoms during the first two weeks of life. Two hundred and twenty-eight newborns were enrolled in the study who were delivered at Kyungpook National University Children’s Hospital between July 2016 and August 2017. The first passed meconium samples were collected for fecal calprotectin analysis. Intestinal distress involved infants with necrotizing enterocolitis (NEC) and other feeding interruption signs. The median gestational age of the population was 37.0 (34.3–38.4) weeks, and the median birth weight was 2635 (2100–3268) g. The median fecal calprotectin levels in meconium were 134.1 (55.6–403.2) μg/g (range: 11.5–2000 μg/g) and the median 25-hydroxyvitamin D (25-OHD) concentrations in cord blood were 21.0 (15.5–28.8) ng/mL. Sixty infants (26.3%) had intestinal distress, including four patients (1.8%) diagnosed as having NEC. Higher fecal calprotectin concentrations (398.2 (131.8–900.2) μg/g vs. 105.6 (39.4–248.5) μg/g, p < 0.001) and lower 25-OHD levels (17.9 (12.8–22.1) ng/mL vs. 23.2 (17.2–33.0) ng/mL, p < 0.001) were found in infants with intestinal distress compared to infants without intestinal distress. The cut-off value was set at 359.8 μg/g with a sensitivity of 0.53 and a specificity of 0.82 for the development of intestinal distress in the first two weeks of life. Serum 25-OHD levels in cord blood were inversely correlated with fecal calprotectin concentrations in meconium.

[A comparative analysis of the efficacy of two vitamin D supplementation regimens in preterm infants: a prospective randomized controlled study]

OBJECTIVE

To study the effect of different vitamin D supplementation regimens on the nutritional status of vitamin D on day 28 after birth in preterm infants with a gestational age of <34 weeks.

METHODS

A total of 59 preterm infants with a gestational age of <34 weeks who were born from October 2018 to October 2019 were enrolled and divided into an observation group with 30 infants and a control group with 29 infants. The infants in the observation group received a single-dose intramuscular injection of vitamin D₃ (10 000 IU/kg), while those in the control group received oral vitamin D₃ drops (900 IU/d) for 25 days. Venous blood samples were collected within 48 hours after birth (before vitamin D₃ supplementation) and on day 28 after birth to measure the serum 25-hydroxyvitamin D [25(OH)D] level.

RESULTS

Within 48 hours after birth, the prevalence rate of vitamin D deficiency (≤15 ng/mL) was 78% among the 59 preterm infants. There were no significant differences in the serum 25(OH)D level and the prevalence rate of vitamin D deficiency between the two groups (P>0.05). Compared with the control group on day 28 after birth, the observation group had a significantly higher serum 25(OH)D level (P<0.05) and a significantly lower prevalence rate of vitamin D deficiency (P<0.05). There were no cases of vitamin D overdose or poisoning.

CONCLUSIONS

In preterm infants with a gestational age of <34 weeks, single-dose intramuscular injection of 10 000 IU/kg vitamin D₃ can significantly increase serum 25(OH)D level on day 28 after birth and safely and effectively reduce the prevalence rate of vitamin D deficiency.

Severe vitamin D deficiency in preterm infants: possibly no association with clinical outcomes?

Purpose: The primary objective of this study was to compare clinical outcomes of very low birth weight (VLBW) infants with 25-hydroxy vitamin D [25(OH)D] levels <25 nmol/l in umbilical cord blood versus VLBW infants with 25(OH)D levels in cord blood >25 nmol/l. The secondary objective was to evaluate umbilical cord vitamin D as a risk factor for respiratory distress syndrome (RDS) in preterm infants.Methods: We examined 25(OH)D levels in umbilical cord blood and in infants' serum at discharge from the neonatal intensive care unit. We evaluated the associations between severe vitamin D deficiency and various laboratory findings and clinical outcomes.Results: Eighty one infants with birth weight less than 1500 g met the entry criteria for this study and were divided to groups according to umbilical cord blood vitamin D [Group A: 25(OH)D < 25 nmol/l; 10 ng/ml and Group B: 25(OH)D > 25 nmol/l; 10 ng/ml]. Overall, 81.5% of the infants had a 25(OH)D level <50 nmol/L and 44.4% had a level <25 nmol/L. The laboratory findings and the subsequent clinical outcomes were comparable in infants in both groups (non-significant difference). Only the infants in the 25(OH)D 25 nmol/L group had a lower calcium in urine at age 28 d (p=.0272). In addition, we found in this study that umbilical cord vitamin D level does not lead to a higher or lower risk of RDS (odds ratio 1.044; 95% confidence interval 0.349-0.88; p=.0771).Conclusions: In our prospective cohort study, we found no significant association between vitamin D status and selected clinical outcomes when using a cut-off of 25 nmol/l (severe vitamin D deficiency) in preterm infants.

SOCS3 protects against neonatal necrotizing enterocolitis via suppressing NLRP3 and AIM2 inflammasome activation and p65 nuclear translocation

BACKGROUND

Necrotizing enterocolitis (NEC) is an acquired disorder of mucosal damage characterized by the diffuse or local necrosis of the intestine. The suppressor of cytokine signaling 3 (SOCS3) has been demonstrated to possess anti-inflammatory action in gastritis, ulcerative colitis and other inflammatory diseases. The present study aims to explore the effects of SOCS3 on LPS-induced colonic cell model of NEC, and investigate the underlying mechanisms.

METHODS

Expression of SOCS3 in tissue samples of NEC and LPS-induced enterocytes were evaluated by real-time quantitative PCR (RT-qPCR). Western blotting and enzyme-linked immunosorbent assay (ELISA) were applied to examine the effect of SOCS3 on inflammatory molecules. Co-immunoprecipitation assay were devoted to explore the relation between SOCS3 and TLR4.

RESULTS

We proved that SOCS3 was expressed at a low level in tissue samples of NEC and LPS-induced enterocytes, and LPS inhibited SOCS3 expression via JAK2/STAT3 pathway. Overexpression of SOCS3 weaken the LPS-induced inflammatory response in FHC and CACO2 cells. Moreover, SOCS3 downregulates proinflammatory cytokines by targeting TLR4, thus mediating the p65 nuclear translocation, and the activation of NLR family pyrin domain containing 3/absent in melanoma-2 (NLRP3/AIM2) inflammasome, ultimately reveals its anti-inflammatory effects.

CONCLUSIONS

Taken together, our data revealed that LPS inhibited SOCS3 expression via JAK2/STAT3 pathway, and SOCS3 protects enterocytes against NEC through mediating p65 nuclear translocation and NLRP3/AIM2 inflammasome activation in a TLR4 dependent manner.

Protective effects of vitamin D against injury in intestinal epithelium

BACKGROUND

Vitamin D deficiency is associated with intestinal barrier dysfunction, which contributes to pathogenesis of acute intestinal injury in children. We aim to investigate the effects of vitamin D on intestinal injury in intestinal epithelial cells and organoids.

METHODS

Lipopolysaccharide (LPS) was used to induce injury in intestinal epithelial cells (IEC-18) and organoids, and the effect of vitamin D was assessed. Cell viability was measured and inflammation cytokines TNFα and IL-8 were quantified. FITC-dextran 4 kDa (FD4) permeability was measured using Transwell while tight junction markers were assessed by immunofluorescence staining in IEC-18 and intestinal organoids. Data were compared using one-way ANOVA with Bonferroni post-test.

RESULTS

IEC-18 viability was decreased by LPS treatment, but was prevented by vitamin D. The upregulation of inflammation was inhibited by vitamin D, which also decreased epithelium permeability. Vitamin D restored tight junction ZO-1 and claudin 2. In addition, vitamin D decreased TNFα expression and prevented the disruption of ZO-1 in injured organoids.

CONCLUSIONS

Vitamin D rescued epithelial barrier function by improving permeability and restoring tight junctions, leading to decrease inflammation. This study confirms the protective effects of vitamin D, which could be used as a treatment strategy for infants at risk of developing intestinal injury.

Impact of Toll-Like Receptor 4 Signaling in Necrotizing Enterocolitis: The State of the Science

Necrotizing enterocolitis (NEC) remains a leading cause of preterm infant mortality. NEC is multifactorial and believed a consequence of intestinal immaturity, microbial dysbiosis, and an exuberant inflammatory response. Over the past decade, exaggerated Toll-like receptor 4 (TLR4) activity in the immature intestine of preterm neonates emerged as an inciting event preceding NEC. Increased TLR4 signaling in epithelial cells results in the initiation of an uncontrolled immune response and destruction of the mucosal barrier. This article discusses the state of the science of the molecular mechanisms involved in TLR4-mediated inflammation during NEC and the development of new therapeutic strategies to prevent NEC.

Association between vitamin D level at birth and respiratory morbidities in very-low-birth-weight infants

Purpose

This study aimed to evaluate vitamin D status at birth in very-low-birth-weight infants (VLBWIs: <1,500 g) and to determine the association between vitamin D level and respiratory morbidity.

Methods

A retrospective study was conducted at Soonchunhyang University Bucheon Hospital between November 2013 and November 2017. We collected blood samples and data on respiratory morbidity from 230 VLBWIs on the first day of life. Patients who were transferred to other hospitals (n=19), died before 36 weeks of gestational age (n=18), or whose blood samples were not collected immediately after birth (n=5) were excluded. Finally, 188 patients were enrolled. VLBWIs with different vitamin D levels were compared with respect to demographic features, maternal diseases, respiratory morbidities, and other neonatal diseases.

Results

The mean serum vitamin D level, as measured by 25-hydroxyvitamin D (25(OH)D), was 13.4± 9.3 ng/mL. The incidence of vitamin D deficiency (<20 ng/mL) was 79.8%, and 44.1% of preterm infants had severe vitamin D deficiency (<10 ng/mL). Logistic analysis shows that a low serum 25(OH)D level (<20 ng/mL) was a risk factor for respiratory distress syndrome (odds ratio [OR], 4.32; P=0.010) and bronchopulmonary dysplasia (OR, 4.11; P=0.035).

Conclusion

The results showed that 79.8% of preterm infants in this study had vitamin D deficiency at birth. Low vitamin D status was associated with respiratory morbidity, but the exact mechanism was unknown. Additional studies on the association between vitamin D level and neonatal morbidity are required.

[Relationship between vitamin D deficiency and necrotizing enterocolitis in preterm infants]

OBJECTIVE

To evaluate the relationship of vitamin D level with the development of necrotizing enterocolitis (NEC) in preterm infants.

METHODS

A total of 429 preterm infants with a gestational age of <36 weeks, who were admitted to the department of neonatology within 2 hours after birth between January and December, 2016, were enrolled in the study. According to whether these infants developed NEC, the 429 subjects were divided into NEC group (n=22) and non-NEC group (n=407). Peripheral venous blood was collected from these preterm infants and their mothers at admission to measure the level of 25-hydroxyvitamin D (25-OHD). The two groups were compared in terms of the serum 25-OHD levels of preterm infants and their mothers. Pearson correlation analysis was used to investigate the correlation between the serum 25-OHD levels of preterm infants and their mothers. The distribution of vitamin D levels in preterm infants was compared between the two groups. The univariate logistic regression analysis was used to determine the risk factors for NEC in preterm infants.

RESULTS

The serum 25-OHD levels of preterm infants and their mothers in the NEC group were significantly lower than in the non-NEC group (P<0.001). In both groups, the serum 25-OHD levels of mothers and preterm infants were positively correlated with each other (P<0.001). The distribution of vitamin D levels (normal vitamin D level, low vitamin D level, vitamin D deficiency, and severe vitamin D deficiency) was significantly different between the NEC and non-NEC groups (P<0.001). The univariate logistic regression analysis showed that gestational age, birth weight, 25-OHD levels of preterm infants and their mothers, the duration of mechanical ventilation, the duration of oxygen inhalation, and the length of hospital stay were associated with the development of NEC (P<0.05).

CONCLUSIONS

The serum 25-OHD levels of preterm infants and their mothers may be related to the development of NEC in preterm infants, suggesting that vitamin D supplementation during pregnancy is important for preventing the development of NEC in preterm infants.

Vitamin D ameliorates neonatal necrotizing enterocolitis via suppressing TLR4 in a murine model

BackgroundThe toll-like receptor 4 (TLR4) has been reported to play an important role in necrotizing enterocolitis (NEC). As an established regulator of TLR4, vitamin D has been demonstrated to be intestinal-protective. This study aims at finding out whether the vitamin D/vitamin D receptor (VDR) pathway ameliorates NEC by regulating TLR4.MethodsSerum 25-hydrovitamin D (25(OH)D) was tested and compared in 15 preterm infants with NEC, 12 preterm infants without known complications and 20 healthy term infants. Neonatal Wistar rats were grouped and NEC was induced through formula feeding and cold/asphyxia stress. Vitamin D and the vehicle were administered to compare the microscopic structure, apoptotic protein expression, intestinal barrier function, inflammatory response, and TLR4 expression.ResultsPreterm infants with NEC had significantly lower 25(OH)D levels than those without NEC and healthy subjects. VDR expression was suppressed, whereas TLR4 expression was elevated in the NEC intestine. Vitamin D may increase the survival rate, alleviate structure damage, and preserve intestinal barrier function. These were achieved partly through restoration of VDR and suppression of TLR4.ConclusionNEC infants have lower levels of vitamin D. The vitamin D/VDR pathway protects against intestinal injury of NEC partly through suppressing the expression of TLR4.