Vitamin D beyond bones in chronic obstructive pulmonary disease: time to act

[Comorbidities in COPD: a new challenge in clinical practice]

Today it is a recognised fact that chronic obstructive pulmonary disease (COPD) is a real systemic disease that is respiratory-based. Recently, the focus has been on the importance of the comorbidities that are associated with COPD, such as all the cardiovascular diseases, lung cancer, diabetes, metabolic syndrome, peripheral muscular dysfunction, depression, anxiety, osteoporosis and anaemia, etc. These comorbidities constitute a new medical and therapeutic challenge with regard to COPD; their high frequency and considerable impact on the quality of life and the prognosis for survival of the patients make them a key element. The aims of this focus are to present the spectrum and prevalence of comorbidities in COPD, to obtain an objective view as to why and how these comorbidities should be systematically assessed and treated in patients, and subsequently to discuss the impact of this new data in clinical practice and in research. This recent data is another positive step in understanding the disease, optimising the diagnosis, and assessing and caring for COPD patients.

Maternal vitamin D receptor genetic variation contributes to infant birthweight among black mothers

Racial disparity in pregnancy outcomes is one of the most striking and poorly understood inequalities in American health. Genetic variability may be an important host factor influencing disparate birth outcomes between non-Hispanic black (NHB) and non-Hispanic white (NHW) women. Race-specific allelic frequencies in the vitamin D receptor (VDR) gene suggest its potential as a gene involved in health disparities. The Healthy Pregnancy, Healthy Baby Study is a prospective cohort of pregnant women aimed at identifying genetic, social, and environmental contributors to disparities in pregnancy outcomes in Durham, NC. VDR haplotype tagging single nucleotide polymorphisms (SNPs) were genotyped via Taqman assays for 615 women. Analysis of variance was used to examine the association between maternal genotype and infant birthweight. Eight of 38 SNPs examined showed nominal significance among NHB women, with one VDR SNP (rs7975232) surpassing the multiple testing significance threshold. rs7975232, an anonymous polymorphism, is part of a VDR gene haplotype associated with variation in mRNA stability. mRNA stability can affect the amount of protein produced, thus directly affecting vitamin D levels and calcium homeostasis. In contrast to NHBs, there was no association between any VDR SNP and birthweight for NHWs. Genetic factors contributing to disparities in birth outcomes are not expected to be explained entirely by variation in a single gene. Nevertheless, our results suggest that maternal VDR gene polymorphisms do influence birthweight with differential effects accruing across racial groups. Further research identifying the functionality of VDR gene polymorphisms in pregnant women will improve our understanding of the underlying mechanisms influencing birthweight.

Vitamin D and chronic lung disease: a review of molecular mechanisms and clinical studies

Vitamin D is classically recognized for its role in calcium homeostasis and skeletal metabolism. Over the last few decades, vitamin D deficiency has increased in prevalence in adults and children. Potential extraskeletal effects of vitamin D have been under investigation for several diseases. Several cross-sectional studies have associated lower vitamin D status with decreased lung function. This finding has prompted investigators to examine the association of vitamin D deficiency with several chronic lung diseases. One major focus has been the link between maternal vitamin D status and childhood asthma. Vitamin D deficiency has also been associated with increased risk of respiratory infection from influenza A and Mycobacterium tuberculosis. Other chronic respiratory diseases associated with vitamin D deficiency include cystic fibrosis, interstitial lung disease, and chronic obstructive pulmonary disease. This review will examine the current clinical literature and potential mechanisms of vitamin D in various pulmonary diseases.

The role of vitamin D in pulmonary disease: COPD, asthma, infection, and cancer

The role of vitamin D (VitD) in calcium and bone homeostasis is well described. In the last years, it has been recognized that in addition to this classical function, VitD modulates a variety of processes and regulatory systems including host defense, inflammation, immunity, and repair. VitD deficiency appears to be frequent in industrialized countries. Especially patients with lung diseases have often low VitD serum levels. Epidemiological data indicate that low levels of serum VitD is associated with impaired pulmonary function, increased incidence of inflammatory, infectious or neoplastic diseases. Several lung diseases, all inflammatory in nature, may be related to activities of VitD including asthma, COPD and cancer. The exact mechanisms underlying these data are unknown, however, VitD appears to impact on the function of inflammatory and structural cells, including dendritic cells, lymphocytes, monocytes, and epithelial cells. This review summarizes the knowledge on the classical and newly discovered functions of VitD, the molecular and cellular mechanism of action and the available data on the relationship between lung disease and VitD status.

Deletion of vitamin D receptor leads to premature emphysema/COPD by increased matrix metalloproteinases and lymphoid aggregates formation

Deficiency of vitamin D is associated with accelerated decline in lung function. Vitamin D is a ligand for nuclear hormone vitamin D receptor (VDR), and upon binding it modulates various cellular functions. The level of VDR is reduced in lungs of patients with chronic obstructive pulmonary disease (COPD) which led us to hypothesize that deficiency of VDR leads to significant alterations in lung phenotype that are characteristics of COPD/emphysema associated with increased inflammatory response. We found that VDR knock-out (VDR(-/-)) mice had increased influx of inflammatory cells, phospho-acetylation of nuclear factor-kappaB (NF-κB) associated with increased proinflammatory mediators, and up-regulation of matrix metalloproteinases (MMPs) MMP-2, MMP-9, and MMP-12 in the lung. This was associated with emphysema and decline in lung function associated with lymphoid aggregates formation compared to WT mice. These findings suggest that deficiency of VDR in mouse lung can lead to an early onset of emphysema/COPD because of chronic inflammation, immune dysregulation, and lung destruction.

Vitamin D deficiency causes deficits in lung function and alters lung structure

RATIONALE

The prevalence of vitamin D deficiency is increasing and has been linked to obstructive lung diseases including asthma and chronic obstructive pulmonary disease. Recent studies suggest that vitamin D deficiency is associated with reduced lung function. The relationship between vitamin D deficiency and lung function is confounded by the association between physical activity levels and vitamin D status. Thus, causal data confirming a relationship between vitamin D and lung function are lacking.

OBJECTIVES

To determine if vitamin D deficiency alters lung structure and function.

METHODS

A physiologically relevant BALB/c mouse model of vitamin D deficiency was developed by dietary manipulation. Offspring from deficient and replete colonies of mice were studied for somatic growth, lung function, and lung structure at 2 weeks of age.

MEASUREMENTS AND MAIN RESULTS

Lung volume and function were measured by plethysmography and the forced oscillation technique, respectively. Lung structure was assessed histologically. Vitamin D deficiency did not alter somatic growth but decreased lung volume. There were corresponding deficits in lung function that could not be entirely explained by lung volume. The volume dependence of lung mechanics was altered by deficiency suggesting altered tissue structure. However, the primary histologic difference between groups was lung size rather than an alteration in architecture.

CONCLUSIONS

Vitamin D deficiency causes deficits in lung function that are primarily explained by differences in lung volume. This study is the first to provide direct mechanistic evidence linking vitamin D deficiency and lung development, which may explain the association between obstructive lung disease and vitamin D status.

Vitamin D and health status in elderly

Recently, vitamin D has aroused considerable interest for several reasons. Many epidemiological studies have shown a widespread deficiency of vitamin D at all ages, and the recent finding that many organs and tissues have vitamin D receptors has fostered the clinical and biological relevance of vitamin D. Elderly people are at high risk for vitamin D deficiency if their life style entails few outdoor activities, their skin is thick and they exhibit impairment of renal function. In the elderly, vitamin D deficiency is very important because it can affect the function of many organs such as the muscle-skeletal, cardio-vascular systems and kidney, and may be involved in various diseases and pathological conditions including type II diabetes, cancer and cognitive decline. In the present review, the most relevant features of vitamin D are described as well as the clinical consequences of hypovitaminosis D in the elderly. Finally, the role of an adequate oral supplementation in the geriatric population is stressed.

Vitamin D effects on lung immunity and respiratory diseases

Our understanding of vitamin D metabolism and biological effects has grown exponentially in recent years and it has become clear that vitamin D has extensive immunomodulatory effects. The active vitamin D generating enzyme, 1α-hydroxylase, is expressed by the airway epithelium, alveolar macrophages, dendritic cells, and lymphocytes indicating that active vitamin D can be produced locally within the lungs. Vitamin D generated in tissues is responsible for many of the immunomodulatory actions of vitamin D. The effects of vitamin D within the lungs include increased secretion of the antimicrobial peptide cathelicidin, decreased chemokine production, inhibition of dendritic cell activation, and alteration of T-cell activation. These cellular effects are important for host responses against infection and the development of allergic lung diseases like asthma. Epidemiological studies do suggest that vitamin D deficiency predisposes to viral respiratory tract infections and mycobacterial infections and that vitamin D may play a role in the development and treatment of asthma. Randomized, placebo-controlled trials are lacking but ongoing.

Vitamin D deficiency and chronic obstructive pulmonary disease: a vicious circle

Vitamin D and vitamin D deficiency strongly interact with different pathogenic mechanisms in COPD. Prevalence of vitamin D deficiency is particularly high in COPD patients, increases with the severity of COPD, and is closely associated with osteoporosis prevalence. Adequate calcium and vitamin D supplementation in COPD patients with documented deficiencies reduces the risk for falling and osteoporotic fractures, may indirectly reduce morbidity, and may potentially prevent the further deterioration of pulmonary function. Apart from the proven beneficial effects of vitamin D supplements on bone and muscle tissue, many epidemiological studies have putatively linked vitamin D deficiency with a higher risk for cardiovascular, inflammatory and infectious diseases, and cancer, diseases known to be associated with and to contribute significantly to the phenotypic presentation of COPD patients. Different animal and human studies have provided considerable evidence on how vitamin D may affect these processes. The burning question in COPD is whether prevention of vitamin D deficiency or adequate supplementation may reverse the natural course of the disease.

A systematic review of the role of vitamin insufficiencies and supplementation in COPD

BACKGROUND

Pulmonary inflammation, oxidants-antioxidants imbalance, as well as innate and adaptive immunity have been proposed as playing a key role in the development of COPD. The role of vitamins, as assessed either by food frequency questionnaires or measured in serum levels, have been reported to improve pulmonary function, reduce exacerbations and improve symptoms. Vitamin supplements have therefore been proposed to be a potentially useful additive to COPD therapy.

METHODS

A systematic literature review was performed on the association of vitamins and COPD. The role of vitamin supplements in COPD was then evaluated.

CONCLUSIONS

The results of this review showed that various vitamins (vitamin C, D, E, A, beta and alpha carotene) are associated with improvement in features of COPD such as symptoms, exacerbations and pulmonary function. High vitamin intake would probably reduce the annual decline of FEV1. There were no studies that showed benefit from vitamin supplementation in improved symptoms, decreased hospitalization or pulmonary function.

Airway obstructive diseases in older adults: from detection to treatment

Asthma and chronic obstructive pulmonary disease occur commonly and may overlap among older adults. Smoking, air pollution, and bronchial hyperresponsiveness are the main risk factors. The treatment of these diseases in older adults does not differ from the available guidelines but may be complicated by the presence of comorbidities. Smoking cessation is essential for smokers, and pulmonary rehabilitation must be considered regardless of the age of the patient.

Update on the management of chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease is a highly prevalent, underdiagnosed, and undertreated chronic lung disease. Early and appropriate treatment may help modify the course of the disease with respect to exacerbation timing and frequency, quality of life, and mortality. Steady progress continues to be made in understanding the disease pathogenesis and treatment modalities, and there is some evidence that outcomes are improving.

Skeletal microstructural abnormalities in postmenopausal women with chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is associated with osteoporosis and fragility fractures. The objectives of this study were to assess static and dynamic indices of cancellous and cortical bone structure in postmenopausal women with COPD. Twenty women with COPD who had not received chronic oral glucocorticoids underwent bone biopsies after double tetracycline labeling. Biopsies were analyzed by histomorphometry and µCT and compared with age-matched controls. Distribution of the patients according to the Global Initiative for Chronic Obstructive Lung Disease (GOLD) was: Type I (15%), Type II (40%), Type III (30%), and Type IV (15%). Mean (±SD) cancellous bone volume (15.20 ± 5.91 versus 21.34 ± 5.53%, p = .01), trabecular number (1.31 ± 0.26 versus 1.77 ± 0.51/mm, p = .003), and trabecular thickness (141 ± 23 versus 174 ± 36 µm, p = .006) were lower in patients than in controls. Connectivity density was lower in COPD (5.56 ± 2.78 versus 7.94 ± 3.08/mm, p = .04), and correlated negatively with smoking (r = -0.67; p = .0005). Trabecular separation (785 ± 183 versus 614 ± 36 µm, p = .01) and cortical porosity (4.11 ± 1.02 versus 2.32 ± 0.94 voids/mm(2); p < .0001) were higher in COPD while cortical width (458 ± 214 versus 762 ± 240 µm; p < .0001) was lower. Dynamic parameters showed significantly lower mineral apposition rate in COPD (0.56 ± 0.16 versus 0.66 ± 0.12 µm/day; p = .01). Patients with more severe disease, GOLD III and IV, presented lower bone formation rate than GOLD I and II (0.028 ± 0.009 versus 0.016+ 0.011 µm(3)/µm(2)/day; p = 04). This is the first evaluation of bone microstructure and remodeling in COPD. The skeletal abnormalities seen in cancellous and cortical bone provide an explanation for the high prevalence of vertebral fractures in this disease.

Vitamin D deficiency and reduced lung function in connective tissue-associated interstitial lung diseases

BACKGROUND

Vitamin D is a steroid hormone with pleiotropic effects including immune system modulation, lung tissue remodeling, and bone health. Vitamin D deficiency has been implicated in the development of autoimmune diseases. We sought to evaluate the prevalence of vitamin D deficiency in a cohort of patients with interstitial lung disease (ILD) and hypothesized that vitamin D deficiency would be associated with an underlying connective tissue disease (CTD) and reduced lung function.

METHODS

Patients in the University of Cincinnati ILD Center database were evaluated for serum 25-hydroxyvitamin D levels as part of a standardized protocol. Regression analysis evaluated associations between 25-hydroxyvitamin D levels and other variables.

RESULTS

One hundred eighteen subjects were included (67 with CTD-ILD, 51 with other forms of ILD). The overall prevalence of vitamin D deficiency and insufficiency in the study population was 38% and 59%, respectively. Those with CTD-ILD were more likely to have vitamin D deficiency (52% vs 20%, P < .0001) and insufficiency (79% vs 31%, P < .0001) than other forms of ILD. Diminished FVC was associated with lower 25-hydroxyvitamin D(3) levels (P = .01). The association between vitamin D insufficiency and CTD-ILD persisted (OR, 11.8; P < .0001) after adjustment for potential confounders. Among subjects with CTD-ILD, reduced 25-hydroxyvitamin D(3) levels were strongly associated with reduced lung function (FVC, P = .015; diffusing capacity for carbon monoxide, P = .004).

CONCLUSIONS

There is a high prevalence of vitamin D deficiency in patients with ILD, particularly those with CTD-ILD, and it is associated with reduced lung function. Vitamin D may have a role in the pathogenesis of CTD-ILD.

Quantification of circulating 25-hydroxyvitamin D by liquid chromatography-tandem mass spectrometry

Hypovitaminosis D is a highly prevalent condition and quantification of serum 25-hydroxyvitamin D3 is accepted to be the most useful marker for the assessment of the individual vitamin D status. Due to the increasing awareness of the prevalence and potential health consequences of hypovitaminosis D, the request numbers for 25-hydroxyvitamin D quantification are growing rapidly in many countries. Automated protein binding assays (based on the use of vitamin D-binding protein or antibodies) for the quantification of 25-hydroxyvitamin D3 are available which enable convenient high-throughput analyses in a routine setting; there is, however, substantial concern about accuracy and analytical reliability of these assays. Several LC-MS/MS methods for the quantification of 25-hydroxyvitamin D3 in serum have been described and in a growing number of clinical laboratories this technology is used routinely for vitamin D monitoring. It is justified to assume that LC-MS/MS enables more reliable analyses of 25-hydroxyvitamin D concentrations compared to protein binding assays. In particular the ability to co-quantify the naturally occurring 25-hydroxyvitamin D3 and 25-hydroxyvitamin D2 which is derived primarily from food fortification is a relevant advantage of LC-MS/MS over protein binding assays. This review describes the background of 25-hydroxyvitamin D measurement, compares published LC-MS/MS methods, discusses problems, strengths and limitations of these assays and compares the application characteristics of LC-MS/MS with those of protein binding assays and HPLC-UV.

Vitamin D status and longitudinal lung function decline in the Lung Health Study

Low blood vitamin D levels have been postulated to be a risk factor for worse lung function, based largely on cross-sectional data. We sought to use longitudinal data to test the hypothesis that baseline plasma 25-hydroxyvitamin D (25(OH)D) is lower in subjects with more rapid lung function decline, compared to those with slow lung function decline. We conducted a nested, matched case-control study in the Lung Health Study 3 cohort. Cases and controls were continuous smokers with rapid and slow lung function decline, respectively, over ~6 yrs of follow-up. We compared baseline 25(OH)D levels between cases and controls, matching date of phlebotomy and clinical centre. Among 196 subjects, despite rapid and slow decliners experiencing strikingly and significantly different rates of decline of forced expiratory volume in 1 s (-152 versus -0.3 mL·yr⁻¹; p < 0.001), there was no significant difference in baseline 25(OH)D levels (25.0 versus 25.9 ng·mL⁻¹; p = 0.54). There was a high prevalence of vitamin D insufficiency (35%) and deficiency (31%); only 4% had a normal 25(OH)D level in the winter. Although vitamin D insufficiency and deficiency are common among continuous smokers with established mild-to-moderate chronic obstructive pulmonary disease, baseline 25(OH)D levels are not predictive of subsequent lung function decline.

Evaluation of vitamin D endocrine system (VDES) status and response to treatment of patients in intensive care units (ICUs) using an on-line SPE-LC-MS/MS method

Vitamin D deficiency is recognized as one of the most common chronic medical conditions in the world. Vitamin deficiency has been associated with increased mortality. The aim of the study here presented was to evaluate the vitamin D endocrine system (VDES) status in healthy blood donors and critically ill patients baseline and in response to treatment during a week with two doses of 1.5 mg of 25-hydroxyvitamin D3 and 2 microg calcitriol (1,25(OH)2D3) IV on alternate days, by monitoring levels in serum of major vitamin D metabolites in critically ill patients. Group 1: healthy blood donors (control group) (n=92), and group 2: critically ill subjects from an intensive care unit (ICU) (n=33). Critically ill patients were divided into three groups: group A (n=12) is the control group; group B (n=11), administration PO 1,5 mg of 25(OH)D3, in days 0 and 4 of treatment; and group C (n=11), administration IV of 2 microg 1,25(OH)2D3 on alternate days. Baseline serum levels of vitamin D2 and 25(OH)D2 were not detected. Vitamin D3 (9.8 vs 26.0 nM) (p<0.05), 25(OH)D3 (13.3 vs 52.3 nM) (p<0.001), and 1,25(OH)2D3 (53.8 vs 120.5 pM) (p<0.01) serum levels were significantly lower in critically ill subjects than in healthy donors. After treatment in group B: 25OHD3 increased to 46.0+/-16.5 ng/ml (p<0.0001) (22.2%<75 nM, 11.1% <50 nM). 1,25(OH)2D3 increased to 121.8+/-61.8 pM<0.01 whereas were slightly decreased in the other groups during the study. 24,25(OH)2D3 serum levels were increased in patients treated with calcitriol 8.5+/-5.3 vs 24.8+/-16.3 nM (p<0.05) while the levels kept stable in group A patients. In summary, critically ill patients have a severe vitamin D deficiency, which can be easily corrected by administration of high doses of 25OHD (PO). The VDES functional deficiency could be probably also corrected through administration of calcitriol (IV). Both treatments could produce an improvement in the general health and probably a reduction in overall mortality risk of the critically ill patients.

Regulatory T cells, inflammation and the allergic response-The role of glucocorticoids and Vitamin D

Regulatory T cells (TRegs) play a central role in the maintenance of peripheral tolerance. They prevent inappropriate immune responses to ubiquitous allergens in healthy individuals, and contribute to the maintenance of immune homeostasis in the airways. Both Foxp3+ and IL-10+ TReg have been implicated in these functions. Glucocorticoids represent the mainstay of treatment for asthma and other allergic conditions, and evidence that steroids influence TReg function will be reviewed. Growing bodies of epidemiological and immunological data suggest a role for endogenous Vitamin D in immune regulation. This review will discuss the role of glucocorticoids and Vitamin D, and their potential interactions in promoting tolerance in the context of allergic disease and asthma.

Why dialysis patients need combination therapy with both cholecalciferol and a calcitriol analogs

The roles of vitamin D, mediated through its conversion to 1,25-dihydroxyvitamin D(3) (calcitriol), have been expanded recently through new knowledge about the range of tissues capable of activating it and the breadth of the genes under its regulatory control. This basic science together with the fact that numerous studies across North America are revealing that vitamin D insufficiency/deficiency (as defined by 25-OH-D levels <30 ng/ml) is extremely common (>80%) in dialysis patients are indicative that these patients have two vitamin D-related problems that require different treatment regimens. Combinations of vitamin D(3) (cholecalciferol) or vitamin D(2) (ergocalciferol) and an active calcitriol analog should be used to treat their vitamin D deficiency and their calcitriol hormone insufficiency, respectively. This mini-review provides the case for combination therapy.

Vitamin D deficiency in the intensive care unit: an invisible accomplice to morbidity and mortality?

The association between vitamin D deficiency and chronic illness is well-known. Vitamin D deficiency has been associated with increased mortality in the general population. Despite this knowledge, vitamin D insufficiency is seldom considered and rarely replaced adequately, if at all, in critically ill patients in intensive care. We present a hypothetic model demonstrating how vitamin D deficiency may be an unrecognized contributor to adverse outcome in intensive care patients.

Long-term therapy in COPD: any evidence of adverse effect on bone?

Patients with COPD have high risk for osteoporosis and fractures. Hip and vertebral fractures might impair mobility, and vertebral fractures further reduce lung function. This review discusses the evidence of bone loss due to medical treatment opposed to disease severity and risk factors for COPD, and therapeutic options for the prevention and treatment of osteoporosis in these patients. A review of the English-language literature was conducted using the MEDLINE database until June 2009. Currently used bronchodilators probably lack adverse effect on bone. Oral corticosteroids (OCS) increase bone resorption and decrease bone formation in a dose response relationship, but the fracture risk is increased more than reflected by bone densitometry. Inhaled corticosteroids (ICS) have been associated with both increased bone loss and fracture risk. This might be a result of confounding by disease severity, but high doses of ICS have similar effects as equipotent doses of OCS. The life-style factors should be modified, use of regular OCS avoided and use of ICS restricted to those with evidenced effect and probably kept at moderate doses. The health care should actively reveal risk factors, include bone densitometry in fracture risk evaluation, and give adequate prevention and treatment for osteoporosis.