Clinical impact of vitamin D treatment in cystic fibrosis: a pilot randomized, controlled trial

Vitamin D deficiency in patients with cystic fibrosis: a systematic review and meta-analysis

AIM

Vitamin D is a prominent modulator of immunity and respiratory function. It plays a vital role in respiratory diseases such as cystic fibrosis (CF). S. However, there is a dearth of information on patients with CF. The purpose of the meta-analysis is to highlight the importance of following the existing guidelines regarding maintenance of Vitamin D serum levels in patients with CF.

METHODS

The systematic search was conducted without utilizing any time or language limitations in original database from the beginning until March 2022. The meta-analysis was performed using a random-effects model. Heterogeneity was determined by I2 statistics and Cochrane Q test.

RESULTS

Pooled analysis using the random-effects model of the 8 case-control studies with 13 effect sizes revealed that the serum 25-OH-vitamin D in participants with cystic fibrosis was significantly lower than controls in pediatrics and adolescences (WMD: - 3.41 ng/ml, 95% CI - 5.02, - 1.80, p =  < 0.001) and adults (WMD: - 2.60 ng/ml, 95% CI - 4.32, - 0.89, p = 0.003). Based on data from 12 studies (21 effect sizes) with a total of 1622 participants, the prevalence of vitamin D levels of 20-30 ng/ml in CF patients was 36% among pediatrics/adolescents and 63% among adults. In addition, 27% of pediatric/adolescent CF patients and 35% of adult CF patients had vitamin D levels of below 20 ng/ml.

CONCLUSIONS

As a result, according to the existing guidelines, our results proved the need to pay attention to the level of vitamin D in these patients.

Changes in bone turnover after high-dose vitamin D supplementation during acute pulmonary exacerbation in cystic fibrosis

In people with cystic fibrosis (CF), chronic inflammation and infection increase the risk for low bone mineral density and CF-related bone disease. During acute pulmonary exacerbations (APE), people with CF have increases in markers of bone resorption. Vitamin D has been proposed as a potential nutrient to lower inflammation. In this ancillary analysis of the Vitamin D for the Immune System in CF study, we hypothesized that vitamin D administered at the time of APE would have favorable changes on bone turnover markers compared to placebo. Participants with CF were randomized to receive a single dose of 250,000 IU of vitamin D or placebo during an APE and followed for 1 year for the primary outcome of APE or death after randomization. Bone turnover markers: C-terminal telopeptide (CTX-1) and procollagen type 1 intact N-terminal propetide (P1NP) were assessed at randomization (during APE) and after recovery from the APE in 45 participants. Participants randomized to vitamin D had significant decreases in markers of bone turnover; participants who received placebo had non-significant increases in markers of bone turnover. Vitamin D supplementation during an APE may help reduce the risk for CF-related bone disease.

Hope in Every Breath: Navigating the Therapeutic Landscape of Cystic Fibrosis

Cystic fibrosis (CF) has long posed a complex challenge to medical science. Still, the tides are turning with remarkable progress in prognosis and demographics, thanks to cutting-edge medical management and treatment breakthroughs. It affects multiple systems, necessitating a comprehensive approach to its management. This article thoroughly reviews the latest advancements in CF treatment across three key areas: respiratory care, infection prevention, and pharmacological management. In respiratory care, emphasis is placed on airway clearance therapies and nebulized saline, while infection prevention strategies encompass hand hygiene, respiratory etiquette, and environmental cleaning and disinfection. Pharmacological management explores pancreatic enzyme replacement therapy (PERT), antimicrobial treatments, cystic fibrosis transmembrane regulator (CFTR) modulators, and promising gene therapies. Patient education and support are highlighted as crucial components of effective CF management, while mental health assessments are emphasized due to CF patients' susceptibility to anxiety and depression. This review highlights the tremendous progress made in the management of CF. Integrating early detection, infection prevention, pharmacological interventions, gene therapy, and patient support is revolutionizing the care and quality of life for individuals with CF.

Systematic review and meta-analysis: Associations of vitamin D with pulmonary function in children and young people with cystic fibrosis

BACKGROUND

Increasing evidence suggests that vitamin D is associated with pulmonary health, which may benefit children and young people diagnosed with Cystic Fibrosis (cypCF). Therefore, the aim of this systematic review was to evaluate primary research to establish associations between 25OHD and pulmonary health in cypCF.

METHODS

Electronic databases were searched with keywords related to CF, vitamin D, children/young people and pulmonary function. Included studies were cypCF (aged ≤21 years) treated in a paediatric setting. The primary outcome was lung function [forced expiratory volume in 1 s (FEV₁% predicted)] and secondary outcomes were rate of pulmonary exacerbations, 25OHD status and growth. Evidence was appraised for risk of bias using the CASP tool, and quality using the EPHPP tool. A Meta-analysis was performed.

RESULTS

Twenty-one studies were included with mixed quality ratings and heterogeneity of reported outcomes. The Meta-analysis including 5 studies showed a significantly higher FEV₁% predicted in the 25OHD sufficiency compared to the deficiency group [FEV₁% predicted mean difference (95% CI) was 7.71 (1.69-13.74) %; p = 0.01]. The mean ± SD FEV₁% predicted for the sufficient (≥75 nmol/L) vs. deficient (<50 nmol/L) group was 94.7 ± 31.9% vs. 86.9 ± 13.2%; I² = 0%; χ² = 0.5; df = 4). Five studies (5/21) found significantly higher rate of pulmonary exacerbations in those who were 25OHD deficient when compared to the sufficient group and negative associations between 25OHD and FEV% predicted. The effects of vitamin D supplementation dosages on 25OHD status (10/21) varied across studies and no study (12/21) showed associations between 25OHD concentration and growth.

CONCLUSION

This systematic review suggests that 25OHD concentration is positively associated with lung function and a concentration of >75 nmol/L is associated with reduced frequency of pulmonary exacerbations, which may slow lung function decline in cypCF. Future randomised clinical trials and mechanistic studies are warranted.

Importance of Vitamin D Status and Nerve Conduction in Pediatric Cystic Fibrosis Patients

Cystic fibrosis is one of the most common inherited diseases. It presents with recurrent respiratory infections, pancreatic insufficiency, and growth retardation. Neurological involvement becomes more common as life expectancy increases. Chronic hypoxia, impaired glucose intolerance, autoimmune mechanisms, vasculitis changes, and micronutrient deficiencies seem to cause neuropathy in cystic fibrosis. This study was aimed to investigate peripheral neuropathy in pediatric cystic fibrosis patients. Twenty-one cystic fibrosis patients and 19 healthy control subjects between the ages of 7 and 17 years were included. Their nerve conduction study results and laboratory investigations were analyzed. Participants were classified into four groups; 1. Cystic fibrosis with vitamin D deficiency, 2. Cystic fibrosis with normal vitamin D levels, 3. Healthy subjects with vitamin D deficiency, 4. Healthy subjects with normal vitamin D levels. We found statistically significantly lower sensory median nerve sensorial nerve action potential, sensorial sural nerve conduction velocity, and motor peroneal nerve compound motor action potential in cystic fibrosis patients with vitamin D deficiency than in other cases. We also found that the main difference between cystic fibrosis and control groups was especially in patients with low vitamin D levels. Nerve damage starts at an early age, especially in cystic fibrosis patients especially those with vitamin D deficiency. Electrophysiological evaluation to assess neuropathy is important even in asymptomatic patients. Prevention of hypovitaminosis D is important to prevent neuropathy in cystic fibrosis patients.

Nutritional Care in Children with Cystic Fibrosis

Patients with cystic fibrosis (CF) are prone to malnutrition and growth failure, mostly due to malabsorption caused by the derangement in the chloride transport across epithelial surfaces. Thus, optimal nutritional care and support should be an integral part of the management of the disease, with the aim of ameliorating clinical outcomes and life expectancy. In this report, we analyzed the nutrition support across the different ages, in patients with CF, with a focus on the relationships with growth, nutritional status, disease outcomes and the use of the CF transmembrane conductance regulator (CFTR) modulators. The nutrition support goal in CF care should begin as early as possible after diagnosis and include the achievement of an optimal nutritional status to support the growth stages and puberty development in children, that will further support the maintenance of an optimal nutritional status in adult life. The cornerstone of nutrition in patients with CF is a high calorie, high-fat diet, in conjunction with a better control of malabsorption due to pancreatic enzyme replacement therapy, and attention to the adequate supplementation of fat-soluble vitamins. When the oral caloric intake is not enough for reaching the anthropometric nutritional goals, supplemental enteral feeding should be initiated to improve growth and the nutritional status. In the last decade, the therapeutic possibilities towards CF have grown in a consistent way. The positive effects of CFTR modulators on nutritional status mainly consist in the improvement in weight gain and BMI, both in children and adults, and in an amelioration in terms of the pulmonary function and reduction of exacerbations. Several challenges need to be overcome with the development of new drugs, to transform CF from a fatal disease to a treatable chronic disease with specialized multidisciplinary care.

Vitamin D attenuates biofilm-associated infections via immunomodulation and cathelicidin expression: a narrative review

INTRODUCTION

Infections are becoming more difficult to treat, at least partly on account of microbes that produce biofilms. Reports suggest that decreased levels of antimicrobial peptides like cathelicidin, elevated levels of inflammatory cytokines, and biofilm formation are all associated with vitamin D deficiency, making vitamin D - deficient individuals more susceptible to infection. Infections attributable to biofilm-producing microbes can be managed by adjuvant therapy with vitamin D because of its immunomodulatory role, particularly because of the ability of vitamin D-pathway to induce the antimicrobial peptides like cathelicidin and decrease proinflammatory cytokines.

AREAS COVERED

This narrative review covers biofilm formation, infections associated with biofilm due to vitamin D deficiency, putative role of vitamin D in host protection and the effect of vitamin D supplementation in biofilm-associated infections. A comprehensive literature search in PubMed and Google Scholar utilizing suitable keywords at multiple time points extracted relevant articles.

EXPERT OPINION

Although vitamin D deficiency has been associated with infections by biofilm producing microbes, comprehensive clinical trials in various ethnicities are required to understand the likely relationships between vitamin D receptor gene expression, cathelicidin levels, and infection outcome. Current evidence hypothesizes that maintaining normal vitamin D level can help prevent and treat these infections.

A Single Vitamin D3 Bolus Supplementation Improves Vitamin D Status and Reduces Proinflammatory Cytokines in Healthy Females

Vitamin D deficiency is a global health problem that not only leads to metabolic bone disease but also to many other illnesses, most of which are associated with chronic inflammation. Thus, our aim was to investigate the safety and effectiveness of a single high dose of vitamin D₃ (80,000 IU) on vitamin D status and proinflammatory cytokines such as interleukin (IL)6, IL8 and tumor necrosis factor (TNF) in healthy Saudi females. Fifty healthy females were recruited and orally supplemented with a single vitamin D₃ bolus (80,000 IU). All participants donated fasting blood samples at baseline, one day and thirty days after supplementation. Serum 25-hydroxyvitamin D₃ (25(OH)D₃), IL6, IL8, TNF, calcium, phosphate, parathyroid hormone (PTH) and blood lipid levels were determined. Serum 25(OH)D₃ significantly increased one and thirty days after supplementation when compared with baseline without causing elevation in calcium or phosphate or a decrease in PTH to abnormal levels. In contrast, the concentrations of the three representative proinflammatory cytokines decreased gradually until the end of the study period. In conclusion, a single high dose (80,000 IU) is effective in improving serum vitamin D status and reducing the concentration of the proinflammatory cytokines in a rapid and safe way in healthy females.

Recent advances in vitamin D implications in chronic respiratory diseases

Chronic airway inflammatory and infectious respiratory diseases are the most common medical respiratory conditions, associated with significant morbidity and mortality. Vitamin D (1,25(OH)₂D₃) deficiency has been shown to be highly prevalent in patients with chronic airway inflammatory and infectious diseases, correlated with increased disease severity. It has been established that vitamin D modulates ongoing abnormal immune responses in chronic respiratory diseases and is shown to restrict bacterial and viral colonization into the lungs. On the contrary, other studies revealed controversy findings regarding vitamin D efficacy in respiratory diseases. This review aims to update the current evidence regarding the role of vitamin D in airway inflammation and in various respiratory diseases. A comprehensive search of the last five years of literature was conducted using MEDLINE and non-MEDLINE PubMed databases, Ovid MEDLINE, SCOPUS-Elsevier, and data from in vitro and in vivo experiments, including clinical studies. This review highlights the importance of understanding the full range of implications that vitamin D may have on lung inflammation, infection, and disease severity in the context of chronic respiratory diseases.

Influences of exocrine pancreatic insufficiency on nutrient digestibility, growth parameters as well as anatomical and histological morphology of the intestine in a juvenile pig model

In a pig model, pancreatic duct ligation (PL) leads to a complete loss of exocrine function, causing an exocrine pancreatic insufficiency (EPI) without affecting endocrine function, allowing research of clinical effects and therapy options. This study aimed to investigate effects of experimentally induced EPI in juvenile pigs on digestion and intestinal morphology. Eight female juvenile cross-bred pigs (BW 54.8 kg at the start of the study) were included. Three animals were considered as a control (CON group), and in five animals the ductus pancreaticus accessorius was ligated (PL group). During the 10-week trial period, body weight and body measurements were recorded regularly. At the end of the trial, gastrointestinal tract (GIT) was investigated macroscopically and histologically and weight and digesta samples of individual segments were obtained. The pigs in the CON showed a significantly higher apparent total tract digestibility of crude protein and crude fat (87.8 and 79.9%, respectively) compared to PL (52.4 and 16.6%, respectively). Significant differences were noted in relative weights of duodenum, jejunum and colon (with and without digesta) and also in absolute weights of jejunum and colon. The mean number of nuclei in the transverse section in stratum circulare were significantly higher in all intestinal segments in CON compared to PL. Overall, EPI results in impaired nutrient digestibility with a greater filling of the GIT with digesta. The elongation of the small intestine does not represent "stretching" of the intestine, but rather increased synthesis of intestinal tissue.

Update on the management of vitamins and minerals in cystic fibrosis

Advancements in respiratory and nutrition management have significantly improved the survival of patients with cystic fibrosis (CF). With the availability of several nutrition interventions such as oral/enteral nutrition supplements, enteric‐coated pancreatic enzymes, and water‐miscible CF‐specific vitamin supplements, frank vitamin deficiencies—with the exception of vitamin D—are rarely encountered in current clinical practice. Whereas they were previously considered as micronutrients, our current understanding of fat‐soluble vitamins and minerals as antioxidants, immunomodulators, and disease biomarkers has been evolving. The impact of highly effective modulators on the micronutrient status of patients with CF remains elusive. This narrative review focuses on the updates on the management of fat‐soluble vitamins and other micronutrients in CF in the current era and identifies the gaps in our knowledge.

The Relation between Vitamin D Level and Lung Clearance Index in Cystic Fibrosis—A Pilot Study

Background: Life expectancy has increased in cystic fibrosis (CF) patients; however, the rate of mortality is still high, and in a majority of cases, the cause of death is due to respiratory deterioration. Vitamin D plays an important role in immunity and infection prophylaxis, as its deficiency is associated with frequent infections. In CF patients, a deficit of liposoluble vitamins is common, despite daily supplementation. The aim of this study is to evaluate the relation between vitamin D status and lung function expressed by lung clearance index (LCI) in patients with CF. We also assessed the relation of factors such as nutritional status, genotype, and associated comorbidities such as Pseudomonas infection, cystic fibrosis-related diabetes (CFRD), and cystic fibrosis liver disease (CFLD) with vitamin D and LCI. Methods: A cross-sectional study was conducted at the National Cystic Fibrosis Center by analyzing patients with CF who presented in our center between November 2017 and November 2019. We enrolled in the study patients diagnosed with CF, who were followed up in our CF center and who were able to perform lung function tests. Patients in exacerbation were excluded. Results: A strong negative correlation was found between vitamin D and LCI (r = −0.69, p = 0.000). A lower vitamin D storage was found in patients with CFLD and CFRD. Higher LCI values were found among patients with chronic Pseudomonas infection, with BMI under the 25th percentile, or with associated CFLD. Conclusion: In CF patients, vitamin D plays an important role, and its deficit correlates with an impaired LCI. Vitamin D deficit is a risk factor in patients with associated comorbidities such as CFLD and CFRD. Chronic infection with Pseudomonas, the presence of impaired nutritional status, and CFLD are associated with a prolonged LCI.

Mucosal Immunity in Cystic Fibrosis

The highly complex and variable genotype-phenotype relationships observed in cystic fibrosis (CF) have been an area of growing interest since the discovery of the CF transmembrane conductance regulator (CFTR) gene >30 y ago. The consistently observed excessive, yet ineffective, activation of both the innate and adaptive host immune systems and the establishment of chronic infections within the lung, leading to destruction and functional decline, remain the primary causes of morbidity and mortality in CF. The fact that both inflammation and pathogenic bacteria persist despite the introduction of modulator therapies targeting the defective protein, CFTR, highlights that we still have much to discover regarding mucosal immunity determinants in CF. Gene modifier studies have overwhelmingly implicated immune genes in the pulmonary phenotype of the disease. In this context, we aim to review recent advances in our understanding of the innate and adaptive immune systems in CF lung disease.

A Clinician’s guide to vitamin D supplementation for patients with cystic fibrosis

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Vitamin D deficiency is multifactorial in the cystic fibrosis population.

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Vitamin D deficiency can adversely affect multiple organ systems in the cystic fibrosis population.

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In the cystic fibrosis population in the United States, we aim to treat to serum 25-hydroxyvitamin D levels over 30 ng/ml.

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Cholecalciferol is used in preference to ergocalciferol.

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Daily or once weekly dosing regimens are chosen according to patient preference and compliance.

Vitamin D deficiency is common in the general population, and even more so in patients with cystic fibrosis. Deficiency is exacerbated in cystic fibrosis patients because of a myriad of causes including malabsorption, decreased fat mass, reduced 25-hydroxylation of vitamin D, reduced exposure to sunlight, decreased vitamin D binding protein, and exposure to drugs that increase catabolism. In turn, vitamin D deficiency can contribute to poor bone health. Additionally, it may contribute to pulmonary decline in the form of worsening pulmonary function, increased colonization with pathogens, and increased pulmonary exacerbation. Because vitamin D deficiency is correlated with negative clinical effects in multiple organ systems of patients with cystic fibrosis, it is important to screen for and treat deficiency in these patients. The Cystic Fibrosis Foundation has issued guidelines for the treatment of vitamin D deficiency, targeting serum levels of 25-hydroxyvitamin D of at least 30 ng/ml. The guidelines offer age-specific escalating dose regimens depending on serum vitamin D levels, with monitoring at 12- week intervals after changing therapy. They address the literature on alternative vitamin D sources, such as UV lamps, ideal formulations (cholecalciferol in preference to ergocalciferol), and optimal vehicles of administration. Despite these detailed recommendations, most centers are still unable to achieve in-target serum vitamin D levels for many of their patients. Future research examining ideal treatment regimens to achieve serum targets and maximize clinical effects are needed. Moreover, it is unknown whether vitamin D sufficiency will be easier to achieve on new triple therapy cystic fibrosis drug combinations, and how these drugs will contribute to vitamin D-related clinical outcomes.

Vitamin D status and pulmonary exacerbations in children and adolescents with cystic fibrosis: Experience from a tertiary care center

Background:

The function of Vitamin D in preventing inflammation and infection has been studied previously for different pathologies in different populations globally. Relationships between serum Vitamin D levels and its effect on pulmonary exacerbations in the cystic fibrosis (CF) population are not well studied in our part of the world. Therefore, we aimed to ascertain the Vitamin D status in pediatric and adolescent CF patients and its association with pulmonary exacerbations.

Materials and Methods:

A retrospective study was conducted at The Aga Khan University Hospital from 2015 to 2018. Patients of CF with sweat chloride value >60 mmol/l and who had at least one measurement of 25 hydroxy Vitamin D (25 OHD) were included in the study. Annual serum Vitamin D levels were documented for enrolled patients and their past 1-year data were analyzed for pulmonary exacerbations, average length of stay, and tracheal/airway colonization with organisms.

Results:

69 patients were included in the study. 28 patients (40.57%) were found to be Vitamin D deficient, 22 patients (31.88%) were Vitamin D insufficient and 19 patients (27.53%) were labeled as Vitamin D insufficient. The average number of exacerbations per year was significantly high in Vitamin D deficient group (3.71 ± 0.96) in comparison with insufficient (3.18 ± 1.09) and sufficient groups (2.26 ± 0.93) (P < 0.001).

Conclusion:

Vitamin D deficiency is related to an increased number of annual pulmonary exacerbations and pseudomonas infections.

Vitamin D supplementation in patients with cystic fibrosis: A systematic review and meta-analysis

Despite routine supplementation, vitamin D insufficiency is often seen in cystic fibrosis (CF) patients on account of pancreatic insufficiency. Vitamin D is a crucial component of bone health and affects nearly all cells of the immune system. However, clinical benefits or harms associated with supplementation are poorly documented. In this systematic review, we included randomized controlled trials (RCTs) that compared vitamin D supplementation with placebo (i.e. 'non-increased dose') in CF patients. Analysing the 8 included RCTs, the intervention group had significantly higher serum 25-hydroxyvitamin D (se25OHD) levels, but there were no significant differences found in the quantitative synthesis of clinical outcomes, including bone disease-, respiratory status- and immunological status-related outcomes. Based on our current results, while a higher vitamin D dose elevates se25OHD, it does not seem to influence clinical outcomes. Future RCTs should include outcomes of past studies and apply longer follow-up periods to document long-term patient-important outcomes.

Factors Contributing to Vitamin D Status at Hospital Admission for Pulmonary Exacerbation in Adults With Cystic Fibrosis

BACKGROUND

Individuals with cystic fibrosis (CF) have difficulty maintaining optimal vitamin D status due to pancreatic insufficiency-induced malabsorption, inadequate sunlight exposure, and poor intake of vitamin D containing foods. Vitamin D deficiency may increase the risk of pulmonary exacerbations of CF. The objective of this study was to assess factors impacting vitamin D status in patients with CF recently hospitalized for a pulmonary exacerbation of CF.

METHODS

This was a pre-planned analysis of vitamin D intake in patients enrolled in a multi-center, double-blind, randomized controlled study examining vitamin D therapy for pulmonary exacerbation of CF. Demographic information, responses from a habitual sun exposure questionnaire and food frequency questionnaire, and vitamin D supplement usage were queried and compared to serum 25-hydroxyvitamin D (25(OH)D) concentrations.

RESULTS

A total of 48 subjects were included in this analysis. Subjects were taking approximately 1,200 IU of vitamin D daily. Reported vitamin D intake, age, race, employment, and education were not significantly associated with vitamin D status in this population. However, smoking status, sunlight exposure in the last 3 years, and skin type (in the bivariate model) were all significantly associated with vitamin D status (all p<0.05).

CONCLUSIONS

Sunlight exposure was the most predictive determinant of vitamin D status in patients with CF prior to pulmonary exacerbation. Subjects reported vitamin D intake below the recommended amounts. The role and mode of optimizing vitamin D status prior to a pulmonary exacerbation needs further investigation.

Association of vitamin D status with lung function measurements in children and adolescents with cystic fibrosis

BACKGROUND

Vitamin D status is considered a potential determinant of lung function in cystic fibrosis (CF). The aim of this retrospective longitudinal study was to investigate the decline of spirometric values in association with vitamin D status.

METHODS

The data regarding 25-hydroxy vitamin D (25OHD) serum levels, spirometric measurements (FEV1, FVC, FEF25-75%), and factors known to be associated with the decline of lung function in CF were retrospectively collected over a 5-year period. The spirometric indices were recorded as the best and the average value of each year, as well as the value, recorded concurrently or closely with 25OHD level measurement.

RESULTS

A significantly positive relationship was observed between 25OHD serum levels and the best annual value of FEV1 (P = .034), and the values of FEV1 (P = .010) and FVC (P = .018) measured concurrently or closely with serum 25OHD levels. The evolution of the best annual value of FEV1 was worse in patients with a mean 5-year value of 25OHD levels less than 20 ng/mL compared with patients with a mean 5-year value of ≥30 ng/mL (P < .001), or ≥20 to <30 (P < .001). There was no significant difference between patients with mean 5-year 25OHD levels ≥30 ng/mL and ≥20 to <30 ng/mL (P = .76).

CONCLUSIONS

Vitamin D status is associated with lung function in patients with CF. Levels of 25OHD above 20 ng/mL were associated with higher best annual FEV1.

Targeting Vitamin D Deficiency to Limit Exacerbations in Respiratory Diseases: Utopia or Strategy With Potential?

Patients with respiratory diseases such as cystic fibrosis, chronic obstructive pulmonary disease, or asthma often experience an acute worsening of respiratory symptoms, termed exacerbations. Although the course of exacerbations is disease specific, they are mostly triggered by a respiratory infection. Exacerbations often require hospitalization and are an important cause of mortality. Treatments of exacerbations aim to minimize the negative impact and to prevent subsequent events. Despite many existing therapy options, many patients do not benefit from therapy and suffer from recurrent events. Vitamin D deficiency is a worldwide problem and is extremely prevalent in these patients. Vitamin D, known for its calcemic effects, also has immunomodulatory and anti-infectious actions and can therefore be a possible agent to treat or prevent exacerbations. This review will focus on vitamin D as a potential candidate to treat or prevent exacerbations in CF, COPD, and asthma.

The Immunomodulatory Role of Vitamin D in Respiratory Diseases

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The growing interest in the new role of vitamin D, particularly as an immunomodulatory factor, has spurred basic research and the development of clinical trials to better understand the influence of supplementation on various diseases. Vitamin D is an important nutrient factor in human health due to its role in calcium metabolism regulation, cellular growth, differentiation and its fundamental discovered activity in immune functions. It has influenced different diseases, particularly inflammatory and autoimmune diseases, through immune response regulation, modulating innate and adaptive immunity.

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The aim of this review was to explore the role of vitamin D in the main respiratory diseases in children such as asthma, chronic rhinosinusitis, cystic fibrosis and recurrent respiratory infections.

Ancestry-specific polygenic scores and SNP heritability of 25(OH)D in African- and European-ancestry populations

Vitamin D inadequacy, assessed by 25-hydroxyvitamin D [25(OH)D], affects around 50% of adults in the United States and is associated with numerous adverse health outcomes. Blood 25(OH)D concentrations are influenced by genetic factors that may determine how much vitamin D intake is required to reach optimal 25(OH)D. Despite large genome-wide association studies (GWASs), only a small portion of the genetic factors contributing to differences in 25(OH)D has been discovered. Therefore, knowledge of a fuller set of genetic factors could be useful for risk prediction of 25(OH)D inadequacy, personalized vitamin D supplementation, and prevention of downstream morbidity and mortality. Using PRSice and weights from published African- and European-ancestry GWAS summary statistics, ancestry-specific polygenic scores (PGSs) were created to capture a more complete set of genetic factors in those of European (n = 9569) or African ancestry (n = 2761) from three cohort studies. The PGS for African ancestry was derived using all input SNPs (a p value cutoff of 1.0) and had an R2 of 0.3%; for European ancestry, the optimal PGS used a p value cutoff of 3.5 × 10-4 in the target/tuning dataset and had an R2 of 1.0% in the validation cohort. Those with highest genetic risk had 25(OH)D that was 2.8-3.0 ng/mL lower than those with lowest genetic risk (p = 0.0463-3.2 × 10-13), requiring an additional 467-500 IU of vitamin D intake to maintain equivalent 25(OH)D. PGSs are a powerful predictive tool that could be leveraged for personalized vitamin D supplementation to prevent the negative downstream effects of 25(OH)D inadequacy.

Lung disease and vitamin D levels in cystic fibrosis infants and preschoolers

INTRODUCTION

Vitamin D acts on the immune system and lung response. Patients with cystic fibrosis (CF) may be deficient in this vitamin. The aims of the study were to evaluate vitamin D levels and severity of lung disease in infants and preschoolers diagnosed with CF, and to compare them to a group of children without pancreatic insufficiency (PI).

METHODS

Patients with CF up to 4 years old were included, and compared to an age-matched group of children without diagnosis of CF. CF group had medical records and High Resolution Thorax Computed Tomography (HRCCT) evaluated in order to verify the severity of lung disease. Information on demographic data, sun exposure habits, supplemental vitamin D therapy, and on the season at the time of vitamin D sampling were collected for both groups.

RESULTS

This study included 45 patients in the CF group and 102 in the non-CF group, with no differences in age (P = 0.327) between them. There was no association between vitamin D levels and markers of lung disease in the CF group. The non-CF group had lower daily sun exposure (P = 0.034), and lower supplementation than the CF group (P < 0.001). Supplementation and seasonality were the determinant variables for vitamin D levels, which were lower for non-supplemented children and for assessments during fall/winter.

CONCLUSION

There was no association between lung disease severity and vitamin D levels in CF group. Supplementation and seasonality were associated to higher vitamin levels.

Vitamin D inhibits pro-inflammatory cytokines in the airways of cystic fibrosis patients infected by Pseudomonas aeruginosa- pilot study

Background

Vitamin D plays an important role in inflammatory responses after antigen exposure. Interleukin-23 (Il-23) promotes Il-17-dependent inflammation during Pseudomonas aeruginosa (P. aeruginosa) pulmonary infection. We aimed to compare the ability of calcitriol and cholecalciferol to modulate the inflammatory response of the CF airways infected with P. aeruginosa.

Methods

This was a randomized, placebo-controlled, double-blind, cross-over trial. Twenty-three patients with CF (aged 6–19), chronically infected by P. aeruginosa were randomly assigned to: calcitriol group receiving 1,25(OH)₂D 0,5 mcg daily or cholecalciferol group receiving cholecalciferol 1000 IU daily for three months. The levels of Il-23 and Il-17A in the exhaled breath concentrate (EBC) were measured. Calcium-phosphorus balance was also evaluated (serum concentration of calcium, phosphorus, 25OHD, parathormone (PTH) and calcium/creatinine ratio in urine). Data were analyzed using means of Stata/Special Edition, release 14.2. A level of P < 0.05 was considered statistically significant.

Results

The level of Il-17A in EBC significantly decreased in calcitriol group from 0,475 pg/mL (± SD 0,515 pg/mL) to 0,384 pg/mL (± SD 0,429 pg/mL) (p = 0,008); there was no change in cholecalciferol group (p = 0,074). The level of Il-23 in EBC did not significantly change in calcitriol group (p = 0,086); there was significant decrease in cholecalciferol group from 8,90 pg/mL (± SD 4,07 pg/mL) to 7,33 pg/mL (± SD 3,88 pg/mL) (p = 0,001). In calcitriol group serum phosphorus and PTH significantly decreased (p = 0,021 and p = 0,019 respectively), the concentration of calcium significantly increased (p = 0,001); there were no changes in cholecalciferol group.

Conclusions

Both analogs of vitamin D revealed their anti-inflammatory effect and reduced the level of Il-17A and Il-23 in the airway of CF patients with chronic P. aeruginosa infection. We observed improvement in calcium-phosphorus metabolism after supplementation with calcitriol, without adverse effects. It is recommended to use vitamin D in CF patients.

Vitamin D for the Immune System in Cystic Fibrosis (DISC): a double-blind, multicenter, randomized, placebo-controlled clinical trial

BACKGROUND

Patients with cystic fibrosis (CF) have increased risk of vitamin D deficiency owing to fat malabsorption and other factors. Vitamin D deficiency has been associated with increased risk of pulmonary exacerbations of CF.

OBJECTIVES

The primary objective of this study was to examine the impact of a single high-dose bolus of vitamin D3 followed by maintenance treatment given to adults with CF during an acute pulmonary exacerbation on future recurrence of pulmonary exacerbations.

METHODS

This was a multicenter, double-blind, placebo-controlled, intent-to-treat clinical trial. Subjects with CF were randomly assigned to oral vitamin D3 given as a single dose of 250,000 International Units (IU) or to placebo within 72 h of hospital admission for an acute pulmonary exacerbation, followed by 50,000 IU of vitamin D3 or an identically matched placebo pill taken orally every other week starting at 3 mo after random assignment. The primary outcome was the composite endpoint of the time to next pulmonary exacerbation or death within 1 y. The secondary outcomes included circulating concentrations of the antimicrobial peptide cathelicidin and recovery of lung function as assessed by the percentage of predicted forced expiratory volume in 1 s (FEV1%).

RESULTS

A total of 91 subjects were enrolled in the study. There were no differences between the vitamin D3 and placebo groups in time to next pulmonary exacerbation or death at 1 y. In addition, there were no differences in serial recovery of lung function after pulmonary exacerbation by FEV1% or in serial concentrations of plasma cathelicidin.

CONCLUSIONS

Vitamin D3 initially given at the time of pulmonary exacerbation of CF did not alter the time to the next pulmonary exacerbation, 12-mo mortality, serial lung function, or serial plasma cathelicidin concentrations. This trial was registered at clinicaltrials.gov as NCT01426256.

Increasing Vitamin D Serum Levels Is Associated With Reduced Pulmonary Exacerbations in Patients With Cystic Fibrosis

CONTEXT

In 2012, The North American Cystic Fibrosis Foundation (NACFF) published new guidelines for the treatment of vitamin D deficiency in individuals with cystic fibrosis (CF).

OBJECTIVE

The objectives of our study were to assess the efficacy of these guidelines, and to test the effect of increasing vitamin D dosage on pulmonary function and exacerbations.

DESIGN

Pulmonary function tests and serum concentrations of 25-hydroxyvitamin D [25(OH)D] were measured 1 year before increasing vitamin D dosage according to the guidelines and at least 1 year later. In addition, days of hospitalization and pulmonary exacerbations were counted and an average per year (average number of days of hospitalization and average number of pulmonary exacerbations [PEA], respectively) was calculated.

SETTING AND PARTICIPANTS

A total of 90 patients from The Cystic Fibrosis Clinic at Hadassah Mount-Scopus Hospital, Jerusalem, Israel.

RESULTS

The mean serum concentration of vitamin D increased significantly from 20.97 ng/mL (52.34 nmol/L) at baseline to 25.41 ng/mL (63.42 nmol/L) at the end of follow-up (P < 0.001). The number of PEA decreased significantly from 2.79 ± 3.96 to 2.15 ± 2.91 (P = 0.007). The change in vitamin D levels was correlated with a decrease in PEA (correlation coefficient = -0.318, P = 0.002).

CONCLUSIONS

The NACFF guidelines for management of vitamin D deficiency improve vitamin D levels in patients with CF but did not reach the normal values in most patients. The increase in vitamin D serum levels was, however, associated with a decrease in number of pulmonary exacerbations.

Updates in vitamin D therapy in cystic fibrosis

PURPOSE OF REVIEW

To summarize recent developments the role of vitamin D and treatment of vitamin D deficiency in cystic fibrosis.

RECENT FINDINGS

Although treatment of low vitamin D levels continues to be important for optimizing bone health in cystic fibrosis, increasing data on the extraskeletal effects of vitamin D are becoming available. Exploratory studies of vitamin D in modulation of respiratory and intestinal microbiomes, and the influence of vitamin D on the metabolomic signature of cystic fibrosis, suggest expanded roles for vitamin D in cystic fibrosis disease and treatment.

SUMMARY

Emerging developments in cystic fibrosis regarding therapeutics and effects of vitamin D on bone health, inflammation, microbiome, and the metabolome are summarized.

Vitamin D intake, serum 25-hydroxy vitamin D and pulmonary function in paediatric patients with cystic fibrosis: a longitudinal approach

Pancreatic-insufficient children with cystic fibrosis (CF) receive age-group-specific vitamin D supplementation according to international CF nutritional guidelines. The potential advantageous immunomodulatory effect of serum 25-hydroxy vitamin D (25(OH)D) on pulmonary function (PF) is yet to be established and is complicated by CF-related vitamin D malabsorption. We aimed to assess whether current recommendations are optimal for preventing deficiencies and whether higher serum 25(OH)D levels have long-term beneficial effects on PF. We examined the longitudinal relationship between vitamin D intake, serum 25(OH)D and PF in 190 CF children during a 4-year follow-up period. We found a significant relationship between total vitamin D intake and serum 25(OH)D (β = 0·02; 95 % CI 0·01, 0·03; P = 0·000). However, serum 25(OH)D decreased with increasing body weight (β = –0·79; 95 % CI –1·28, –0·29; P = 0·002). Furthermore, we observed a significant relationship between serum 25(OH)D and forced expiratory volume in 1 s (β = 0·056; 95 % CI 0·01, 0·102; P = 0·018) and forced vital capacity (β = 0·045; 95 % CI 0·008, 0·082; P = 0·017). In the present large study sample, vitamin D intake is associated with serum 25(OH)D levels, and adequate serum 25(OH)D levels may contribute to the preservation of PF in children with CF. Furthermore, to maintain adequate levels of serum 25(OH)D, vitamin D supplementation should increase with increasing body weight. Adjustments of the international CF nutritional guidelines, in which vitamin D supplementation increases with increasing weight, should be considered.

Vitamin D3 supplementation in adults with bronchiectasis: A pilot study

Vitamin D supplementation prevents acute respiratory infections and, through modulating innate and adaptive immunity, could have a potential role in bronchiectasis management. The primary aims of this pilot study were to assess serum 25-hydroxyvitamin D (25(OH)D) levels in New Zealand adults with bronchiectasis, and their 25(OH)D levels after vitamin D3 supplementation. Adults with bronchiectasis received an initial 2.5 mg vitamin D3 oral loading dose and 0.625 mg vitamin D3 weekly for 24 weeks. The primary outcome was serum 25(OH)D levels before and after vitamin D3 supplementation. Secondary outcomes (time to first infective exacerbation, exacerbation frequency, spirometry, health-related quality of life measures, sputum bacteriology and cell counts and chronic rhinosinusitis) were also assessed. This study is registered with the Australian New Zealand Clinical Trials Registry (ACTRN 12612001222831). The initial, average 25(OH)D level was 71 nmol/L (95% confidence interval (CI): [58, 84]), rising to 218 nmol/L (95% CI: [199, 237]) at 12 weeks and 205 nmol/L (95% CI: [186, 224]) at 24 weeks. The initial serum cathelicidin level was 25 nmol/L (95% CI: [17, 33]), rising to 102 nmol/L (95% CI: [48, 156]) at 12 weeks and 151 nmol/L (95% CI: [97, 205]) at 24 weeks. Over the 24-week study period, we observed statistically significant changes of 1.11 (95% CI: [0.08, 2.14]) in the Leicester Cough Questionnaire and -1.97 (95% CI: [-3.71, -0.23]) in the Dartmouth COOP charts score. No significant adverse effects were recorded. Many New Zealand adults with bronchiectasis have adequate 25(OH)D levels. Weekly vitamin D3 supplementation significantly improved 25(OH)D levels.

Impact of nutritional status on pulmonary function after lung transplantation for cystic fibrosis

Background

Nutritional status is an important prognostic factor in patients with cystic fibrosis (CF) prior to lung transplantation.

Objective

To investigate the impact of nutritional status on pulmonary function in CF transplant recipients.

Methods

Adult double lung transplanted CF patients were consecutively included. The predictive value of nutritional status on lung function - measured by spirometry - was longitudinally assessed by body composition serially evaluated by a three-compartment model bioelectrical impedance analysis (BIA) in comparison to body mass index (BMI).

Results

Overall, 147 spirometries and 147 BIAs were performed in 58 patients (59% female, median age: 30.1 years, median BMI: 19.6 kg/m²). Malnourished patients (BMI < 18.5 kg/m²; 27.6%) had a significantly reduced lung function compared to normal/overweight patients (forced expiratory volume in 1 second in percent (FEV1%pred), 57% vs 77%; p = 0.024). BMI, as well as the BIA parameters phase angle, total body water, fat free mass, body cell mass (BCM) and extracellular mass (ECM)/BCM ratio, were univariate predictors of FEV1%pred. When included in a linear mixed model, ECM/BCM ratio remained the only significant predictor of lung function (p = 0.012).

Conclusion

Nutritional status assessed by BIA predicted lung function in CF transplant recipients. Serial BIA measurements to monitor patients' nutritional status might help to improve or maintain lung function.

Children with cystic fibrosis demonstrate no respiratory immunological, infective or physiological, consequences of vitamin D deficiency

BACKGROUND

Vitamin D has health benefits in many respiratory diseases but the evidence in CF is unclear. Induction of the antimicrobial peptides cathelicidin (LL37) and human-beta-defensin-2 (HBD-2) may be the mechanism of any benefit. We hypothesised that antimicrobial peptide levels would be decreased, and airway infection and inflammation greater, in CF children with vitamin D deficiency. The objective of the study was to explore relationships between vitamin D, LL37 and HBD-2, and airway infection, inflammation and physiology in children with CF.

METHODS

Bronchoalveolar lavage (BALF) and blood were obtained from children undergoing fibreoptic bronchoscopy. Serum vitamin D, BALF HBD-2 and LL37, cultured bacteria and inflammatory markers were measured. Clinical parameters were recorded.

RESULTS

113 patients with CF, 23 with non-CF chronic suppurative lung disease (CSLD) and 6 healthy controls were included. We found no relationship between serum vitamin D and BALF HBD-2 or LL-37. There were no differences in infective or inflammatory markers between vitamin D sufficient and deficient groups. Vitamin D deficient patients (<50 nmol/L) did not have a worse FEV₁ (CF: 66 (58-71)% vs. 71.5 (61-76)%, ns; non-CF CSLD: 69 (36-88)% vs. 70 (62-95)%, ns).

CONCLUSIONS

In the first bronchoscopic study exploring this question, we demonstrate that vitamin D deficiency is not associated with immunological, infective or clinical markers of disease severity in patients with CF or CSLD.

Vitamin D treatment modulates immune activation in cystic fibrosis

Persistent inflammatory response in cystic fibrosis (CF) airways is believed to play a central role in the progression of lung damage. Anti-inflammatory treatment may slow lung disease progression, but adverse side effects have limited its use. Vitamin D has immunoregulatory properties. We randomized 16 CF patients to receive vitamin D2, vitamin D3 or to serve as controls, and investigated the effect of vitamin D supplementation on soluble immunological parameters, myeloid dendritic cells (mDCs) and T cell activation. Three months of vitamin D treatment were followed by two washout months. Vitamin D status at baseline was correlated negatively with haptoglobin, erythrocyte sedimentation rate and immunoglobulin A concentration. Total vitamin D dose per kg bodyweight correlated with the down-modulation of the co-stimulatory receptor CD86 on mDCs. Vitamin D treatment was associated with reduced CD279 (PD-1) expression on CD4⁺ and CD8⁺ T cells, as well as decreased frequency of CD8⁺ T cells co-expressing the activation markers CD38 and human leucocyte antigen D-related (HLA-DR) in a dose-dependent manner. There was a trend towards decreased mucosal-associated invariant T cells (MAIT) cell frequency in patients receiving vitamin D and free serum 25-hydroxyvitamin D (free-s25OHD) correlated positively with CD38 expression by these cells. At the end of intervention, the change in free-s25OHD was correlated negatively with the change in CD279 (PD-1) expression on MAIT cells. Collectively, these data indicate that vitamin D has robust pleiotropic immunomodulatory effects in CF. Larger studies are needed to explore the immunomodulatory treatment potential of vitamin D in CF in more detail.