25-Hydroxyvitamin D concentrations, asthma and eczema in childhood: The generation R study

Vitamin D has an effect on airway inflammation and Th17/Treg balance in asthmatic mice

Asthma is regarded as a chronic inflammation of the airway. Research has highlighted the significance of Vitamin D in asthma. This study explored the mechanism of vitamin D on asthma. The asthma mouse model was established by ovalbumin (OVA) sensitization and treated with vitamin D (50 or 100 ng/ml). The morphological changes of the airway were observed by HE staining. The serum IgE contents and MDA, ROS, and SOD expressions in the bronchoalveolar lavage fluid (BALF) were detected by ELISA. The Th17 and Treg cells were detected using flow cytometry. The RORγt and Foxp 3 expressions were detected by Reverse transcription quantitative polymerase chain reaction (RT-qPCR). IL-17, IL-10, and TGF-β1 expressions were detected using ELISA. The NF-κB pathway was blocked using the NF-κB pathway inhibitor, Andrographolide sulfonate. The NF-κB pathway-related indexes were detected by western blotting. After blockade of the NF-κB pathway, the IL-17, IL-10, and TGF-G1 expressions were detected. OVA-sensitized asthma induced airway remodeling and elevated IgE content in mice, which was downregulated after vitamin D treatment. MDA and ROS were upregulated and SOD was downregulated in asthmatic mice, while vitamin D inverted the changes. Th17/Treg ratio was imbalanced, RORγt and IL-17 were upregulated, and Foxp 3, IL-10, and TGF-β1 were downregulated after OVA sensitization, while vitamin D treatment inverted these changes and inhibited the NF-κB-p65 phosphorylation level. After blockade of the NF-κB pathway, IL-17 was downregulated and IL-10 and TGF-β1 were upregulated. In conclusion, vitamin D rectified the Th17/Treg balance and alleviated airway inflammation by inhibiting the NF-κB pathway in asthmatic mice.

Vitamin D and childhood asthma: causation and contribution to disease activity

PURPOSE OF REVIEW

To review the literature of the past 18 months (April 2017 through September, 2018) relating to vitamin D and childhood asthma.

RECENT FINDINGS

A combined analysis of two clinical trials of maternal vitamin D supplementation trials showed a significant protective effect of vitamin D supplementation trials in the primary prevention of asthma and recurrent wheeze up to age 3 years. Secondary analyses from these trials have also suggested that initial maternal vitamin D status could affect the response to supplementation during pregnancy, with the biggest protective effect in children born to mothers with initial 25hydroxyvitamin D (25OHD) levels of at least 30 ng/ml. A postnatal, 6-month vitamin D supplementation trial in black, premature babies showed a 34% decreased risk of recurrent wheezing at 1 year among the infants who received supplementation. An individual patient data meta-analysis of published clinical trials concluded that vitamin D supplementation decreased the risk of asthma exacerbations in those with 25OHD levels less than 10 ng/ml. Results of observational analyses on primary prevention of asthma and in prevention of exacerbations remain mixed, with the bulk of the evidence suggesting that there is a protective effect of higher vitamin D levels.

SUMMARY

Evidence continues to accumulate that vitamin D supplementation helps to prevent the development of asthma and recurrent wheeze in early life, and may also help in the management of asthma. The level(s) of circulating vitamin D that maximizes these effects remains to be identified.

Targeting cell signaling in allergic asthma

Asthma is chronic inflammation of the airways characterized by airway hyper-responsiveness, wheezing, cough, and dyspnea. Asthma affects >350 million people worldwide. The Th2 immune response is a major contributor to the pathophysiology of asthma. Targeted therapy modulating cell signaling pathways can be a powerful strategy to design new drugs to treat asthma. The potential molecular pathways that can be targeted include IL-4-IL-13-JAK-STAT-MAP kinases, adiponectin-iNOS-NF-κB, PGD2-CRTH2, IFNs-RIG, Wnt/β-catenin-FAM13A, FOXC1-miR-PI3K/AKT, JNK-Gal-7, Nrf2-ROS, Foxp3-RORγt, CysLTR, AMP, Fas-FasL, PTHrP/PPARγ, PAI-1, FcɛRI-LAT-SLP-76, Tim-3-Gal-9, TLRs-MyD88, PAR2, and Keap1/Nrf2/ARE. Therapeutic drugs can be designed to target one or more of these pathways to treat asthma.

Maternal and neonatal 25-hydroxyvitamin D concentrations and school-age lung function, asthma and allergy. The Generation R Study

BACKGROUND

Vitamin D deficiency in early life might affect the developing lung and immune system, and subsequently influence the risk of asthma and allergy in later life.

OBJECTIVE

We examined the associations of 25-hydroxyvitamin D concentrations in mid-gestation and at birth with lung function, asthma, inhalant allergic sensitization and inhalant allergy at school-age.

METHODS

This study among 4951 children and their mothers was embedded in a population-based prospective cohort in Rotterdam, the Netherlands. Maternal venous blood samples in mid-gestation and umbilical cord blood samples at birth were used to determine 25-hydroxyvitamin D concentrations. At age 10 years, lung function was measured by spirometry, current asthma and physician-diagnosed inhalant allergy by questionnaire, and inhalant allergic sensitization by skin prick tests. We used multivariable regression models to examine associations.

RESULTS

Higher 25-hydroxyvitamin D concentrations in mid-gestation were associated with a higher forced vital capacity (FVC), but a lower forced expiratory volume in 1 second/FVC (FEV₁ /FVC) and a lower forced expiratory flow after exhaling 75% of FVC (FEF₇₅ ) (Z-score differences [95% CI] 0.02 [0.00, 0.03], -0.02 [-0.03, -0.01] and -0.01 [-0.03, -0.00], respectively, per 10 nmol/L 25-hydroxyvitamin D), but not with asthma. Furthermore, higher 25-hydroxyvitamin D concentrations in mid-gestation were associated with an increased risk of inhalant allergy (Odds Ratio [95% CI] 1.07 [1.02, 1.12]), but not with inhalant allergic sensitization. After additional adjustment for child's 25-hydroxyvitamin D concentrations at the age of 6 years, only the associations of 25-hydroxyvitamin D concentrations in mid-gestation with FEV₁ /FVC and FEF₇₅ remained. We did not find consistent associations of 25-hydroxyvitamin D concentrations at birth with respiratory or allergy outcomes.

CONCLUSION AND CLINICAL RELEVANCE

Our results suggest that maternal 25-hydroxyvitamin D concentrations in mid-gestation may influence lung development. The clinical implications of the observed associations remain unclear.

Vitamin D alleviates airway remodeling in asthma by down-regulating the activity of Wnt/β-catenin signaling pathway

Vitamin D exerts a protective role in asthma; however, the molecular mechanisms underlying the vitamin D-attenuated asthma airway remodeling are yet to be elucidated. In this study, Sprague-Dawley (SD) rats were randomly divided into four groups: control, asthma, vitamin D 50 ng/mL, and vitamin D 100 ng/mL. The treatment with 100 ng/mL vitamin D remarkably reduced the thickness of the airway smooth muscle, collagen deposition, and the alpha-smooth muscle actin (α-SMA) mass and airway inflammation. Conversely, the treatment by vitamin D significantly up-regulated the serum levels of 25(OH)₂D₃ that were decreased in asthma. The putative signaling pathway of vitamin D was based on Wnt5a and β-catenin expression assessed by quantitative real-time reverse transcription polymerase chain reaction (RT-qPCR) and Western blot, which revealed that the administration of vitamin D significantly decreased the activity of Wnt/β-catenin signaling pathway. These results suggested that administration of vitamin D alleviated the airway remodeling in asthma by down-regulating the activity of Wnt/β-catenin signaling pathway.

A decrease in vitamin D levels is associated with methotrexate-induced oral mucositis in children with acute lymphoblastic leukemia

Purpose

Children with acute lymphoblastic leukemia (ALL) are at increased risk of vitamin D deficiency, which might make them more susceptible to developing adverse events. Previous studies showed that low vitamin D levels were associated with an increased inflammatory mucosal state and impaired mucosal tissue barriers. We examined the prevalence of vitamin D deficiency and studied the association between vitamin D levels and methotrexate (MTX)-induced oral mucositis in pediatric ALL.

Methods

We assessed 25-hydroxyvitamin D (25(OH)D₃) and 24,25-dihydroxyvitamin D (24,25(OH)₂D₃) levels in 99 children with ALL before the start of 4 × 5 g/m² high-dose methotrexate (HD-MTX) (T0) and in 81/99 children after discontinuation of HD-MTX (T1). Two cutoff values for vitamin D deficiency exist: 25(OH)D₃ levels < 30 and < 50 nmol/L. Oral mucositis was defined as grade ≥ 3 according to the National Cancer Institute Criteria.

Results

Vitamin D deficiency occurred in respectively 8% (< 30 nmol/L) and 33% (< 50 nmol/L) of the patients at T0, and more frequently in children > 4 years of age as compared to children between 1 and 4 years of age. A decrease in 25(OH)D₃ levels during HD-MTX therapy was associated with developing severe oral mucositis (OR 1.6; 95% CI [1.1–2.4]). 25(OH)D₃ and 24,25(OH)₂D₃ levels at T0 and the change in 24,25(OH)₂D₃ levels during therapy were not associated with the development of severe oral mucositis.

Conclusions

This study showed that vitamin D deficiency occurs frequently in pediatric ALL patients above the age of 4 years. A decrease in 25(OH)D₃ levels during MTX therapy was observed in children with ALL that developed severe oral mucositis.

Electronic supplementary material

The online version of this article (10.1007/s00520-018-4312-0) contains supplementary material, which is available to authorized users.

Vitamin D in pediatric age: consensus of the Italian Pediatric Society and the Italian Society of Preventive and Social Pediatrics, jointly with the Italian Federation of Pediatricians

Vitamin D plays a pivotal role in the regulation of calcium-phosphorus metabolism, particularly during pediatric age when nutritional rickets and impaired bone mass acquisition may occur.Besides its historical skeletal functions, in the last years it has been demonstrated that vitamin D directly or indirectly regulates up to 1250 genes, playing so-called extraskeletal actions. Indeed, recent data suggest a possible role of vitamin D in the pathogenesis of several pathological conditions, including infectious, allergic and autoimmune diseases. Thus, vitamin D deficiency may affect not only musculoskeletal health but also a potentially wide range of acute and chronic conditions. At present, the prevalence of vitamin D deficiency is high in Italian children and adolescents, and national recommendations on vitamin D supplementation during pediatric age are lacking. An expert panel of the Italian Society of Preventive and Social Pediatrics reviewed available literature focusing on randomized controlled trials of vitamin D supplementation to provide a practical approach to vitamin D supplementation for infants, children and adolescents.

The Role of Vitamin D in the Immune System as a Pro-survival Molecule

PURPOSE

Vitamin D is a fascinating and attractive molecule that has gained particular attention in medicine in recent years. Its immunomodulatory and anti-inflammatory potential might resemble the activity of many nature-derived molecules (eg, flavonoids), but its role in biology was selected during a long evolutionary pathway to dampen the damaging effect of cell stress response and of the immune reaction. In this sense, this molecule can be considered an ancient hormone that serves, in its primary role, as a pro-survival agent. The goal of this review was to elucidate this topic.

METHODS

The article reviews current literature on the field, focusing on issues regarding the role of vitamin D in immunity.

FINDINGS

Vitamin D participates in the survival machinery used by the cell, and in particular it plays a major role in synchronizing calcium oscillatory signaling to allow cell autophagy or apoptosis during a stress response.

IMPLICATIONS

Vitamin D should be better highlighted in its molecular action and vitamin D receptor genomics to conceive a more suited therapeutic supplementation protocol in clinics.