Alterations in vitamin D status and anti-microbial peptide levels in patients in the intensive care unit with sepsis

Cathelicidin impact on inflammatory cells

Cathelicidins, like other antimicrobial peptides, exhibit direct antimicrobial activities against a broad spectrum of microbes, including both Gram-positive and Gram-negative bacteria, enveloped viruses, and fungi. These host-derived peptides kill the invaded pathogens by perturbing their cell membranes and can neutralize biological activities of endotoxin. Nowadays, more and more data indicate that these peptides, in addition to their antimicrobial properties, possess various immunomodulatory activities. Cathelicidins have the potential to influence and modulate, both directly and indirectly, the activity of various cell populations involved in inflammatory processes and in host defense against invading pathogens. They induce migration of neutrophils, monocytes/macrophages, eosinophils, and mast cells and prolong the lifespan of neutrophils. These peptides directly activate inflammatory cells to production and release of different pro-inflammatory and immunoregulatory mediators, cytokines, and chemokines, however cathelicidins might mediate the generation of anti-inflammatory cytokines as well. Cathelicidins also modulate epithelial cell/keratinocyte responses to infecting pathogens. What is more, they affect activity of monocytes, dendritic cells, keratinocytes, or epithelial cells acting in synergy with cytokines or β-defensins. In addition, these peptides indirectly balance TLR-mediated responses of monocytes, macrophages, dendritic cells, epithelial cells, and keratinocytes. This review discusses the role and significance of cathelicidins in inflammation and innate immunity against pathogens.

Effects of vitamin D supplementation on intestinal permeability, cathelicidin and disease markers in Crohn's disease: Results from a randomised double-blind placebo-controlled study

BACKGROUND

Vitamin D (vitD) supplementation may prolong remission in Crohn's disease (CD); however, the clinical efficacy and mechanisms are unclear.

AIM

To determine changes in intestinal permeability (IP), antimicrobial peptide (AMP) concentrations and disease markers in CD, in response to vitD supplementation.

METHODS

In a double-blind randomised placebo-controlled study, we assigned 27 CD patients in remission to 2000 IU/day vitD or placebo for 3 mos. We determined IP, plasma cathelicidin (LL-37 in ng/mL), human-beta-defensin-2 (hBD2 in pg/mL), disease activity (Crohn's Disease Activity Index (CDAI)), C-reactive protein (CRP in mg/L), fecal calprotectin (µg/g), Quality of Life (QoL) and serum 25-hydroxyvitamin D (25(OH)D in nmol/L) at 0 and 3 mos.

RESULTS

At 3 mos., 25(OH)D concentrations were significantly higher in those whom were treated (p < 0.001). Intra-group analysis showed increased LL-37 concentrations (p = 0.050) and maintenance of IP measures in the treated group. In contrast, in the placebo group, the small bowel (p = 0.018) and gastro-duodenal permeability (p = 0.030) increased from baseline. At 3 mos., patients with 25(OH)D ≥ 75 nmol/L had significantly lower CRP (p = 0.019), higher QoL (p = 0.037), higher LL-37 concentrations (p < 0.001) and non-significantly lower CDAI scores (p = 0.082), compared to those with levels <75 nmol/L.

CONCLUSION

Short-term treatment with 2000 IU/day vitD significantly increased 25(OH)D levels in CD patients in remission and it was associated with increased LL-37 concentrations and maintenance of IP. Achieving 25(OH)D ≥ 75 nmol/l was accompanied by higher circulating LL-37, higher QoL scores and reduced CRP. Registered at ClinicalTrials.gov (NCT01792388).

Vitamin D and Calcium Attenuate Bone Loss With Antiretroviral Therapy Initiation: A Randomized Trial

BACKGROUND

Antiretroviral therapy initiation for HIV-1 infection is associated with 2% to 6% loss of bone mineral density (BMD).

OBJECTIVE

To evaluate the effect of vitamin D3 plus calcium supplementation on bone loss associated with antiretroviral therapy initiation.

DESIGN

48-week prospective, randomized, double-blind, placebo-controlled study. (ClinicalTrials.gov: NCT01403051).

SETTING

39 AIDS Clinical Trials Group units.

PATIENTS

Adults with antiretroviral therapy-naive HIV.

MEASUREMENTS

BMD by dual-energy x-ray absorptiometry, 25-hydroxyvitamin D levels, and other laboratory assessments.

RESULTS

165 eligible patients were randomly assigned (79 received vitamin D3 plus calcium and 86 received placebo). The study groups were well-balanced at baseline: 90% were men, 33% were non-Hispanic black, and the median CD4 count was 0.341 × 109 cells/L. At 48 weeks, the percentage of decline in total hip BMD was smaller in the vitamin D3 plus calcium group than in the placebo group: Medians were -1.36% (interquartile range [IQR], -3.43% to 0.50%) and -3.22% (IQR, -5.56% to -0.88%), respectively (P = 0.004). Similar results were seen at the lumbar spine. At 48 weeks, 90% of patients achieved HIV-1 RNA levels less than 50 copies/mL. Levels of 25-hydroxyvitamin D3 increased with vitamin D3 plus calcium but not with placebo: Median change was 61.2 nmol/L (IQR, 36.4 to 94.3) versus 1.7 nmol/L (IQR, -13.2 to 10.7) (P < 0.001). Overall, 103 patients (62%) reported 1 or more adverse event, with similar distribution between groups; no cases of hypercalcemia and 1 case of nephrolithiasis were reported in the placebo group.

LIMITATION

No international sites were included, and follow-up was only 48 weeks.

CONCLUSION

Vitamin D3 plus calcium supplementation mitigates the BMD loss seen with initiation of efavirenz/emtricitabine/tenofovir disoproxil fumarate.

Vitamin D Metabolites and Their Association with Calcium, Phosphorus, and PTH Concentrations, Severity of Illness, and Mortality in Hospitalized Equine Neonates

Background

Hypocalcemia is a frequent abnormality that has been associated with disease severity and outcome in hospitalized foals. However, the pathogenesis of equine neonatal hypocalcemia is poorly understood. Hypovitaminosis D in critically ill people has been linked to hypocalcemia and mortality; however, information on vitamin D metabolites and their association with clinical findings and outcome in critically ill foals is lacking. The goal of this study was to determine the prevalence of vitamin D deficiency (hypovitaminosis D) and its association with serum calcium, phosphorus, and parathyroid hormone (PTH) concentrations, disease severity, and mortality in hospitalized newborn foals.

Methods and Results

One hundred newborn foals ≤72 hours old divided into hospitalized (n = 83; 59 septic, 24 sick non-septic [SNS]) and healthy (n = 17) groups were included. Blood samples were collected on admission to measure serum 25-hydroxyvitamin D₃ [25(OH)D₃], 1,25-dihydroxyvitamin D₃ [1,25(OH) ₂D₃], and PTH concentrations. Data were analyzed by nonparametric methods and univariate logistic regression. The prevalence of hypovitaminosis D [defined as 25(OH)D₃ <9.51 ng/mL] was 63% for hospitalized, 64% for septic, and 63% for SNS foals. Serum 25(OH)D₃ and 1,25(OH) ₂D₃ concentrations were significantly lower in septic and SNS compared to healthy foals (P<0.0001; P = 0.037). Septic foals had significantly lower calcium and higher phosphorus and PTH concentrations than healthy and SNS foals (P<0.05). In hospitalized and septic foals, low 1,25(OH)₂D₃ concentrations were associated with increased PTH but not with calcium or phosphorus concentrations. Septic foals with 25(OH)D₃ <9.51 ng/mL and 1,25(OH) ₂D₃ <7.09 pmol/L were more likely to die (OR=3.62; 95% CI = 1.1-12.40; OR = 5.41; 95% CI = 1.19-24.52, respectively).

Conclusions

Low 25(OH)D₃ and 1,25(OH)₂D₃ concentrations are associated with disease severity and mortality in hospitalized foals. Vitamin D deficiency may contribute to a pro-inflammatory state in equine perinatal diseases. Hypocalcemia and hyperphosphatemia together with decreased 1,25(OH)₂D₃ but increased PTH concentrations in septic foals indicates that PTH resistance may be associated with the development of these abnormalities.

Significant association between vitamin D deficiency and sepsis: a systematic review and meta-analysis

Background

A number of observational studies have found an association between low vitamin D levels and risk of sepsis. We conducted a systematic review and meta-analysis to determine the overall estimate of risk.

Methods

This was a systematic review and meta-analysis conducted by online searches (CENTRAL, PubMed/MEDLINE, and EMBASE) was registered in PROSPERO (CRD42014014767). Primary outcome was incidence, prevalence, relative risk or odds ratio of having sepsis or bloodstream infection between patients with vitamin D deficiency and controls.

Results

The initial search yielded 647 articles. Twenty-one articles underwent full-length review and data were extracted from 10 observational studies. Pooled odds ratio of sepsis in participants with vitamin D deficiency was 1.78 (95 % confidence interval [CI] = 1.55 to 2.03, p < 0.01) compared with controls in studies that reported participant numbers and was 1.45 (95 % CI = 1.26 to 1.66, p < 0.01) in studies that reported an adjusted odds ratio of vitamin D deficiency for developing sepsis. Statistical between-study heterogeneity was low (I² = 0 % and 5 %, respectively). Standardized mean difference of 25-hydroxyvitamin D levels in patients with sepsis and controls was −0.24 (95 % CI = −0.49 to 0.00, p = 0.05) and lower in the sepsis group compared with non-sepsis or control participants. The statistical between-study heterogeneity (I²) was 0 %.

Conclusion

Vitamin D deficiency were associated with an increased susceptibility of sepsis.

Electronic supplementary material

The online version of this article (doi:10.1186/s12871-015-0063-3) contains supplementary material, which is available to authorized users.

Antimicrobial peptide LL-37 circulating levels in chronic obstructive pulmonary disease patients with high risk of frequent exacerbations

BACKGROUND

Exacerbations of chronic obstructive pulmonary disease (COPD) increase the decline in lung function, deterioration in health status and risk of death. The assessment of exacerbation risk is important in the grading of COPD. The most common cause of COPD exacerbation is respiratory tract infection. The only known human cathelicidin antimicrobial peptide, LL-37, play an important role in innate defense against infection. Its gene expression is regulated by the bioactive form of vitamin D. The objective of the present study was to explore the relationship between LL-37 plasma levels, vitamin D status and exacerbation risk in patients with COPD.

METHODS

COPD patients and normal subjects were recruited from Beijing Hospital for this study. COPD patients were divided into low risk group and high risk group according to the criteria of GOLD strategy. The plasma concentrations of LL-37 were measured by ELISA technique to explore the difference in LL-37 levels between groups. The plasma levels of 25-hydroxy vitamin D [25(OH)D] were analyzed using electrochemiluminescence immunoassay (ECLIA).

RESULTS

A total of 84 COPD patients and 51 normal subjects (control group) were recruited. COPD patients were divided into low risk group (37 cases) and high risk group (47 cases), depending on forced expiratory volume in one second (FEV1)%pred and exacerbation frequency in the previous year. The plasma concentrations of LL-37 in control group, low risk group and high risk group were 20.7±5.8, 19.5±4.1 and 17.9±3.9 µg/L respectively. The plasma concentration of LL-37 was significantly lower in high risk group than in control group (P=0.006). But there was no significant difference between low risk group and high risk group (P=0.152). The plasma concentrations of 25(OH)D in control group, low risk group and high risk group were 18.1±9.4, 13.1±6.9 and 9.3±5.8 ng/mL respectively. The plasma concentration of 25(OH)D was significantly higher in control group than in low risk group (P=0.004) or high risk group (P<0.001). The plasma concentration of 25(OH)D was significantly lower in high risk group than in low risk group (P=0.031). Hospitalization frequency for COPD exacerbations was negative correlated with plasma levels of LL-37 (r=-0.290, P=0.048) and 25(OH)D (r=-0.341, P=0.020) in high risk group. There was not significant correlation between LL-37 and 25(OH)D in COPD patients (r=0.115, P=0.303).

CONCLUSIONS

The plasma levels of LL-37 and 25(OH)D were lower in COPD patients with high risk of frequent exacerbations than normal subjects. Low plasma levels of LL-37 and 25(OH)D might be predictors of exacerbation risk in COPD patients.

Low Vitamin D and High Fibroblast Growth Factor 23 Serum Levels Associate with Infectious and Cardiac Deaths in the HEMO Study

Longitudinal studies testing the relationship between repeated measures of vitamin D or fibroblast growth factor 23 (FGF23) and infectious and cardiac hospitalizations and death in hemodialysis patients have not been reported. We examined the association between yearly 25-hydroxyvitamin D (25(OH)D), 1,25-dihydroxyvitamin D (1,25(OH)2D), and FGF23 serum levels and various clinical outcomes using time-dependent Cox regression models with repeated yearly measures and fixed-covariate Cox models with only baseline values after controlling for important clinical covariates in the HEMO study. During a median follow-up of 3 years, 582 of the 1340 participants died, and 499 and 514 participants had a hospitalization or death attributed to infectious and cardiac causes, respectively. Patients in the highest 25(OH)D quartile had the lowest risk of infectious events (hazard ratio [HR] 0.66 versus the lowest quartile; 95% confidence interval [95% CI], 0.49-0.89), cardiac events (HR, 0.71; 95% CI, 0.53-0.96), and all-cause mortality (HR, 0.46; 95% CI, 0.34-0.62) in time-dependent analyses. No significant associations of 1,25(OH)2D with clinical outcomes were observed in time-dependent or fixed-covariate Cox models. In contrast, the highest FGF23 quartile was associated with a higher risk of infectious events (HR, 1.57 versus the lowest quartile; 95% CI, 1.13-2.18), cardiac events (HR, 1.49; 95% CI, 1.06-2.08), and all-cause mortality (HR, 1.50; 95% CI, 1.07-2.12) in fixed-covariate Cox models. The addition of inflammation markers into the statistical models did not attenuate these associations. Thus, disordered mineral metabolism may affect outcomes in chronic hemodialysis patients.

Vitamin D deficiency is independently associated with mortality among critically ill patients

OBJECTIVE

Studies suggest an association between vitamin D deficiency and morbidity/mortality in critically ill patients. Several issues remain unexplained, including which vitamin D levels are related to morbidity and mortality and the relevance of vitamin D kinetics to clinical outcomes. We conducted this study to address the association of baseline vitamin D levels and vitamin D kinetics with morbidity and mortality in critically ill patients.

METHOD

In 135 intensive care unit (ICU) patients, vitamin D was prospectively measured on admission and weekly until discharge from the ICU. The following outcomes of interest were analyzed: 28-day mortality, mechanical ventilation, length of stay, infection rate, and culture positivity.

RESULTS

Mortality rates were higher among patients with vitamin D levels <12 ng/mL (versus vitamin D levels >12 ng/mL) (32.2% vs. 13.2%), with an adjusted relative risk of 2.2 (95% CI 1.07-4.54; p< 0.05). There were no differences in the length of stay, ventilation requirements, infection rate, or culture positivity.

CONCLUSIONS

This study suggests that low vitamin D levels on ICU admission are an independent risk factor for mortality in critically ill patients. Low vitamin D levels at ICU admission may have a causal relationship with mortality and may serve as an indicator for vitamin D replacement among critically ill patients.

Vitamin D: Immuno-modulation and tuberculosis treatment

Tuberculosis (TB) is a major global health problem and often coincides with vitamin D deficiency. High doses of vitamin D were widely used to treat TB during the pre-antibiotic era. Vitamin D exerts its action through vitamin D receptor (VDR), and VDR gene polymorphisms are associated with susceptibility or resistance to tuberculosis as well as sputum smear and culture conversion during anti-TB treatment. In-vitro studies have revealed that 1,25-dihydroxyvitamin D3 enhances innate immunity by increased expression of various antimicrobial peptides, including cathelicidin, and induction of autophagy of the infected cells thus restricts the intracellular growth of Mycobacterium tuberculosis in macrophages. On the other hand, vitamin D has been shown to suppress the pro-inflammatory cytokine response and enhance the anti-inflammatory response. Supplementation with vitamin D in concert with treatment for TB may be beneficial with respect to minimizing the excessive tissue damage that occurs during the active stage of tuberculosis disease. Several clinical trials have evaluated vitamin D supplementation as an adjunct therapy in the treatment for tuberculosis. However, results are conflicting, owing to variations in dose regimens and outcomes. Further investigations are needed to find the optimal concentration of vitamin D for supplementation with standard anti-TB drugs to optimize treatment, which could help to effectively manage both drug-sensitive and drug-resistant tuberculosis.

Vitamin D status and the risk for hospital-acquired infections in critically ill adults: a prospective cohort study

INTRODUCTION

To identify patient characteristics associated with low serum 25-hydroxyvitamin D (25(OH)D) concentrations in the medical intensive care unit (ICU) and examine the relationship between serum 25(OH)D and the risk for hospital-acquired infections.

METHODS

This is a prospective observational cohort of adult patients admitted to the medical ICU at an urban safety net teaching hospital in Atlanta, Georgia from November 1, 2011 through October 31, 2012 with an anticipated ICU stay ≥ 1 day. Phlebotomy for serum 25(OH)D measurement was performed on all patients within 5 days of ICU admission. Patients were followed for 30 days or until death or hospital discharge, whichever came first. Hospital-acquired infections were determined using standardized criteria from review of electronic medical record.

RESULTS

Among the 314 patients analyzed, 178 (57%) had a low vitamin D at a serum 25(OH)D concentration < 15 ng/mL. The patient characteristics associated with low vitamin D included admission during winter months (28% vs. 18%, P = 0.04), higher PaO2/FiO2 (275 vs. 226 torr, P = 0.03) and a longer time from ICU admission to study phlebotomy (1.8 vs. 1.5 days, P = 0.02). A total of 36 (11%) patients were adjudicated as having a hospital-acquired infection and in multivariable analysis adjusting for gender, alcohol use, APACHE II score, time to study phlebotomy, ICU length of stay and net fluid balance, serum 25(OH)D levels < 15 ng/mL were not associated with risk for hospital-acquired infections (HR 0.85, 95% CI 0.40-1.80, P = 0.7).

CONCLUSIONS

In this prospective, observational cohort of adults admitted to a single-center medical ICU, we did not find a significant association between low 25(OH)D and the risk for hospital-acquired infections.

Dose-response effect of ergocalciferol therapy on serum 25-hydroxyvitamin D concentration during critical illness

OBJECTIVE

The aim of this study was to evaluate the dose-response relationship between ergocalciferol therapy and serum 25-hydroxyvitamin D concentrations in enterally fed, critically ill patients with traumatic injuries.

METHODS

A retrospective cohort of critically ill patients with traumatic injuries and vitamin D deficiency (25-OH vitamin D <50 nmol/L) were given either 50 000 IU of liquid ergocalciferol weekly, twice weekly, or three times weekly while in the intensive care unit (ICU). Serum 25-OH vitamin D and ionized calcium concentrations were monitored weekly. Ergocalciferol therapy was stopped when the serum 25-OH vitamin D was >75 nmol/L, if the patient experienced hypercalcemia (ionized calcium >1.34 mmol/L), when the patient was discharged from the ICU, or if enteral nutrition was discontinued.

RESULTS

Sixty-five patients (16, 18, and 31 per dosage group) were examined. One (6%), two (11%), and eight (26%) patients achieved normal 25-OH vitamin D concentrations after 2 to 4 wk of ergocalciferol therapy for each dosage group, respectively (P < 0.001). Serum 25-OH vitamin D concentrations improved from 36 ± 6, 40 ± 7, and 37 ± 6 nmol/L to 50 ± 15, 54 ± 21, and 62 ± 17 nmol/L, respectively, after 2 wk of ergocalciferol therapy (P < 0.001) Two (13%), one (6%), and seven (23%) patients developed hypercalcemia for each dosage group, respectively (P = NS).

CONCLUSIONS

Ergocalciferol therapy improved baseline serum 25-OH vitamin D concentrations but was inadequate for consistently achieving normal serum concentrations of 25-OH vitamin D during critical illness. The trend in increasing appearance of mild hypercalcemia for the highest dosage group is concerning.

Cathelicidin antimicrobial protein, vitamin D, and risk of death in critically ill patients

INTRODUCTION

Decreased production of cathelicidin antimicrobial protein-18 (hCAP18) has been proposed to be a key mechanism linking decreased 25-hydroxyvitamin D (25D) levels with adverse outcomes among critically ill patients. However, few studies in humans have directly assessed plasma hCAP18 levels, and no study has evaluated the association between hCAP18 levels and adverse outcomes among critically ill patients.

METHODS

We performed a single-center, prospective cohort study among 121 critically ill patients admitted to intensive care units (ICUs) between 2008 and 2012. We measured plasma hCAP18, 25D, D-binding protein, and parathyroid hormone levels on ICU day 1. The primary endpoint was 90-day mortality. Secondary endpoints included hospital mortality, sepsis, acute kidney injury, duration of mechanical ventilation, and hospital length of stay.

RESULTS

ICU day 1 hCAP18 levels were directly correlated with 25D levels (Spearman's rho (rs) = 0.30, P = 0.001). In multivariate analyses adjusted for age and Acute Physiology and Chronic Health Evaluation II (APACHE II) score, patients with hCAP18 levels in the lowest compared to highest tertile on ICU day 1 had a 4.49 (1.08 to 18.67) greater odds of 90-day mortality, and also had greater odds of sepsis. ICU day 1 levels of other analytes were not associated with 90-day mortality.

CONCLUSIONS

Lower 25D levels on ICU day 1 are associated with lower hCAP18 levels, which are in turn associated with a greater risk of 90-day mortality. These findings provide a potential mechanistic basis for the frequently observed association between low 25D levels and poor outcomes in critically ill patients.

Vitamin D supplementation in the ICU patient

PURPOSE OF REVIEW

Recent findings suggest that vitamin D is a marker for outcomes in critical illness. The purpose of this review is to summarize current biological, observational and interventional evidence in the critically ill.

RECENT FINDINGS

Both biological and observational studies support the role of vitamin D deficiency in adverse critical illness outcomes. Interventional trials of critically ill patients show that to improve vitamin D status, high-dose vitamin D3 is required. Critically ill patients have a relatively blunted response to vitamin D supplementation compared to the general outpatient population. Toxicity from high-dose vitamin D in trials in the critically ill has been limited to mild hypercalcemia. Recent evidence suggests that treatment of severely vitamin D-deficient critically ill patients with high-dose vitamin D early in the ICU course may improve mortality.

SUMMARY

Vitamin D deficiency is a potentially modifiable marker for adverse outcomes in critical illness and critical illness survivors. Vitamin D supplementation is inexpensive and appears safe in critical illness trials. A well powered interventional trial is required to determine the definitive answer regarding the role of vitamin D supplementation in the improvement of critical care outcomes. Until such data are available, a cautious approach to correction of vitamin D status in the ICU is warranted.

Supraphysiological 25-hydroxy vitamin D3 level at admission is associated with illness severity and mortality in critically ill patients

We studied the association between admission serum 25-hydroxy vitamin D3 level and in-hospital mortality in a prospective cohort of critically ill patients admitted to the medical intensive care unit of a tertiary care referral center. Of the 180 patients enrolled, 129 were included. Vitamin D3 deficiency was observed in 37% (n = 48) and supra-physiological levels (≥250 nmol/L) in 15.5% (n = 20). Patients with supraphysiological vitamin D3 levels were grouped as outliers. There was no difference in mortality (p = 0.41) between vitamin D3 deficient (21/48) and non-deficient (36/81) patients in analysis with and without outliers. Patients with vitamin D3 ≥250 nmol/L had a significantly higher (p = 0.02) Simplified Acute Physiology Score (SAPS) II and mortality (p = 0.003) [mean (SD) 60.1 ± 17.1 and 75% (15/20), respectively] when compared with the rest [45.6 ± 18 and 38.5% (42/109), respectively]. The sensitivity, specificity and SAPS II independent odds ratio to predict mortality in patients with supraphysiological vitamin D3 levels were 26.3, 93.1 and 3.7% (95% confidence interval 1.2-11.4; p = 0.03), respectively. In conclusion, vitamin D3 deficiency in our cohort was not associated with mortality. A patient subset with supra-physiological vitamin D levels had higher illness severity scores and mortality. Extrinsic factors interfering with test results were ruled out. A biological hypothesis to explain this observation is proposed. Further clarification of mechanisms leading to this observation is warranted.

Vitamin D as an adjunctive therapy in asthma. Part 1: A review of potential mechanisms

Vitamin D deficiency (VDD) is highly prevalent worldwide. The classical role for vitamin D is to regulate calcium absorption form the gastrointestinal tract and influence bone health. Recently vitamin D receptors and vitamin D metabolic enzymes have been discovered in numerous sites systemically supporting diverse extra-skeletal roles of vitamin D, for example in asthmatic disease. Further, VDD and asthma share several common risk factors including high latitude, winter season, industrialization, poor diet, obesity, and dark skin pigmentation. Vitamin D has been demonstrated to possess potent immunomodulatory effects, including effects on T cells and B cells as well as increasing production of antimicrobial peptides (e.g. cathelicidin). This immunomodulation may lead to asthma specific clinical benefits in terms of decreased bacterial/viral infections, altered airway smooth muscle-remodeling and -function as well as modulation of response to standard anti-asthma therapy (e.g. glucocorticoids and immunotherapy). Thus, vitamin D and its deficiency have a number of biological effects that are potentially important in altering the course of disease pathogenesis and severity in asthma. The purpose of this first of a two-part review is to review potential mechanisms whereby altering vitamin D status may influence asthmatic disease.

An update on the association of vitamin D deficiency with common infectious diseases

Vitamin D plays an important role in modulating the immune response to infections. Deficiency of vitamin D is a common condition, affecting both the general population and patients in health care facilities. Over the last decade, an increasing body of evidence has shown an association between vitamin D deficiency and an increased risk for acquiring several infectious diseases, as well as poorer outcomes in vitamin D deficient patients with infections. This review details recent developments in understanding the role of vitamin D in immunity, the antibacterial actions of vitamin D, the association between vitamin D deficiency and common infections (like sepsis, pneumonia, influenza, methicillin-resistant Staphylococcus aureus, human immunodeficiency virus type-1 (HIV), and hepatitis C virus (HCV)), potential therapeutic implications for vitamin D replacement, and future research directions.

On the Functional Overlap between Complement and Anti-Microbial Peptides

Intriguingly, activated complement and anti-microbial peptides share certain functionalities; lytic, phagocytic, and chemo-attractant activities and each may, in addition, exert cell instructive roles. Each has been shown to have distinct LPS detoxifying activity and may play a role in the development of endotoxin tolerance. In search of the origin of complement, a functional homolog of complement C3 involved in opsonization has been identified in horseshoe crabs. Horseshoe crabs possess anti-microbial peptides able to bind to acyl chains or phosphate groups/saccharides of endotoxin, LPS. Complement activity as a whole is detectable in marine invertebrates. These are also a source of anti-microbial peptides with potential pharmaceutical applicability. Investigating the locality for the production of complement pathway proteins and their role in modulating cellular immune responses are emerging fields. The significance of local synthesis of complement components is becoming clearer from in vivo studies of parenchymatous disease involving specifically generated, complement-deficient mouse lines. Complement C3 is a central component of complement activation. Its provision by cells of the myeloid lineage varies. Their effector functions in turn are increased in the presence of anti-microbial peptides. This may point to a potentiating range of activities, which should serve the maintenance of health but may also cause disease. Because of the therapeutic implications, this review will consider closely studies dealing with complement activation and anti-microbial peptide activity in acute inflammation (e.g., dialysis-related peritonitis, appendicitis, and ischemia).

Human-derived cathelicidin LL-37 directly activates mast cells to proinflammatory mediator synthesis and migratory response

Cathelicidins, a family of antimicrobial peptides, are well known for their role in host defense, particularly against bacteria. Apart from direct killing of microbes through the membrane disruption, cathelicidins can also exert immunomodulatory effects on cells involved in inflammatory processes. Considering the important role of mast cells in inflammation, the aim of this study was to determine whether LL-37, human-derived cathelicidin, can induce mast cell activation. We have observed that LL-37 directly stimulates mast cell to degranulation and production of some proinflammatory cytokines, but fails to induce cysteinyl leukotriene generation and release. We have also documented that LL-37 acts as a strong mast cell chemoattractant. In intracellular signaling in mast cells activated by LL-37 participates PLC/A2 and, in part, MAPKs, and PI3K. In conclusion, our results indicate that cathelicidins may enhance antibacterial inflammatory response via attracting mast cell to pathogen entry site and via induction of mast cell-derived mediator release.

The relationship between immediate preoperative serum 25-hydroxy-vitamin D₃ levels and cardiac function, dysglycemia, length of stay, and 30-d readmissions in cardiac surgery patients

OBJECTIVES

Vitamin D has pleiotropic effects on cardiac, renal, and endocrine diseases like diabetes mellitus and deficiency has been correlated with increased Intensive Care Unit (ICU) morbidity and mortality. We studied the relationship between preoperative Vitamin D levels and several short-term endpoints including cardiovascular events, glucose levels, ICU, and hospital length of stay.

METHODS

Standard demographic data were obtained. Blood samples were drawn for 25-hydroxy-vitamin D3 (Vit D) levels at baseline (just before induction of anesthesia) and on postoperative day (POD #1). The number of inotropes used on POD # 0, 1, and 2 was recorded as well as the Cardiac Index (CI). Baseline glucose, Blood Urea Nitrogen and Creatinine (Cr) levels were obtained and repeated on POD # 1 & 2. Other variables studied are number of days of ICU and hospital stay.

RESULTS

Of the 64 patients included in the cohort, 3 were excluded because of inadequate data. 69% had Vit D levels <20 ng/mL and 31% had levels ≥20 ng/mL. More than 90% of the cohort had a significant decrease in POD # 1 Vit D levels (P < 0.001). Age, sex, race, and body mass index did not predict the preoperative Vit D levels; however, the timing of surgery was associated with preoperative Vit D levels, lowest in subjects who had surgery performed during winter. Preoperative Vit D levels had no effect on postoperative glycemic control, cardiac index, or composite outcome-arrhythmias, respiratory failure, or prolonged inotropic support. On regression analysis, preoperative Vit D levels did show a significant effect on ICU and hospital length of stay in this cohort.

CONCLUSIONS

The low levels in this study truly represent the Vit D status as they were obtained before any intervention, including surgery or fluid administration. Vit D levels decreased rapidly after surgery and hence future studies on Vit D may need to focus on premorbid levels obtained at the time of initial presentation and not those obtained after resuscitation or ICU admission. In contrast to epidemiologic reports, we found no association between low Vit D levels and postoperative cardiovascular events. However, low Vit D levels did affect the ICU and hospital length of stay in patients who were undergoing cardiac surgery. This is an important finding especially when many institutions and regulatory agencies are investigating novel therapies and processes to reduce the length of hospitalization. More studies are required to investigate the effect on hospital length of stay of early preadmission or preoperative Vit D supplementation before elective surgery.

Vitamin D deficiency as a risk factor for infection, sepsis and mortality in the critically ill: systematic review and meta-analysis

Introduction

In Europe, vitamin D deficiency is highly prevalent varying between 40% and 60% in the healthy general adult population. The consequences of vitamin D deficiency for sepsis and outcome in critically ill patients remain controversial. We therefore systematically reviewed observational cohort studies on vitamin D deficiency in the intensive care unit.

Methods

Fourteen observational reports published from January 2000 to March 2014, retrieved from Pubmed and Embase, involving 9,715 critically ill patients and serum 25-hydroxyvitamin D₃ (25 (OH)-D) concentrations, were meta-analysed.

Results

Levels of 25 (OH)-D less than 50 nmol/L were associated with increased rates of infection (risk ratio (RR) 1.49, 95% (confidence interval (CI) 1.12 to 1.99), P = 0.007), sepsis (RR 1.46, 95% (CI 1.27 to 1.68), P <0.001), 30-day mortality (RR 1.42, 95% (CI 1.00 to 2.02), P = 0.05), and in-hospital mortality (RR 1.79, 95% (CI 1.49 to 2.16), P <0.001). In a subgroup analysis of adjusted data including vitamin D deficiency as a risk factor for 30-day mortality the pooled RR was 1.76 (95% CI 1.37 to 2.26, P <0.001).

Conclusions

This meta-analysis suggests that vitamin D deficiency increases susceptibility for severe infections and mortality of the critically ill.

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-014-0660-4) contains supplementary material, which is available to authorized users.

Vitamin D Deficiency in Pediatric Critical Illness

Introduction

The potential role for vitamin D in infection has been well described in adults. The objective of our study was to determine the prevalence of vitamin D insufficiency and to evaluate the relationship between vitamin D status and markers of innate immunity and infection in critically ill children.

Hypothesis

Vitamin D deficiency is highly prevalent in children with critical illness and correlates with the severity of illness and dysfunction in innate immunity.

Methods

We performed a prospective clinical observational study with both case and control groups in the pediatric intensive care unit (PICU). Vitamin D status was defined as vitamin D sufficient (25-hydroxyvitamin D (25(OH)D ≥ 20 ng/mL), vitamin D insufficient (25(OH)D 10–20 ng/mL), and vitamin D deficient (25(OH)D <10 ng/mL). Vitamin D status, severity of illness scores, and cathelicidin, and other clinical data were collected.

Results

Sixty-one PICU patients and 46 control patients were enrolled. Over 60% of the PICU cases were found to be vitamin D insufficient while less than 1/3 of the controls were insufficient (p < 0.0001). No significant correlation was seen between plasma 25(OH)D and any severity of illness scores. Cases with asthma had a significantly lower median level 25(OH)D (16.9 ng/mL) than cases without asthma (18.7 ng/mL). Over 50% of patients hospitalized during the fall and winter were considered vitamin D deficient or insufficient whereas in the sunnier seasons (spring and summer) the prevalence of vitamin D deficiency/insufficiency decreased to about 30% (p = 0.003).

Conclusions

Vitamin D deficiency is common in the pediatric critical care population. Significant seasonal differences were noted even in the critically ill. The role of vitamin D in certain diseases like asthma in critically ill children merit further study.

Cellular metabolism and macrophage functional polarization

Macrophages are a functionally heterogeneous cell population that is mainly shaped by a variety of microenvironmental stimuli. Interferon γ (IFN-γ), interleukin-1β (IL-1β), and lipopolysaccharide (LPS) induce a classical activation of macrophages (M1), whereas IL-4 and IL-13 induce an alternative activation program in macrophages (M2). Reprogramming of intracellular metabolisms is required for the proper polarization and functions of activated macrophages. Similar to the Warburg effect observed in tumor cells, M1 macrophages increase glucose consumption and lactate release and decreased oxygen consumption rate. In comparison, M2 macrophages mainly employ oxidative glucose metabolism pathways. In addition, fatty acids, vitamins, and iron metabolisms are also related to macrophage polarization. However, detailed metabolic pathways involved in macrophages have remained elusive. Understanding the bidirectional interactions between cellular metabolism and macrophage functions in physiological and pathological situations and the regulatory pathways involved may offer novel therapies for macrophage-associated diseases.

The association of serum vitamin D concentration with serious complications after noncardiac surgery

BACKGROUND

Vitamin D deficiency is a global health problem. Epidemiological studies demonstrate that vitamin D is both cardioprotective and neuroprotective. Vitamin D also plays a substantial role in innate and acquired immunity. Our goal was to evaluate the association of serum vitamin D concentration on serious postoperative complications and death in noncardiac surgical patients.

METHODS

We retrospectively analyzed the data of 3509 patients who had noncardiac surgery at the Cleveland Clinic Main Campus and had a serum vitamin D measurement. The relationship between serum vitamin D concentration and all-cause in-hospital mortality, in-hospital cardiovascular morbidity, and serious in-hospital infections was assessed as a common effect odds ratio (OR) by using a multivariate generalized estimating equation model with adjustment for demographic, medical history variables, and type and duration of surgery.

RESULTS

Higher vitamin D concentrations were associated with decreased odds of in-hospital mortality/morbidity (P = 0.003). There was a linear reduction of the corresponding common effect odds ratio (OR 0.93, 95% confidence interval, 0.88-0.97) for severe in-hospital outcomes for each 5 ng/mL increase in vitamin D concentration over the range from 4 to 44 ng/mL. In addition, we found that the odds versus patients with vitamin D <13 ng/mL (i.e., 1st quintile) were significantly lower in patients with vitamin D 13-20, 20-27, 27-36, and > 36 ng/mL (i.e., 2nd-5th quintiles); the corresponding estimated ORs were 0.65 (99% confidence interval, 0.43-0.98), 0.53 (0.35-0.80), 0.44 (0.28-0.70), and 0.49 (0.31-0.78), respectively. However, there was no statistically significant difference among individual quintiles >13 ng/mL.

CONCLUSIONS

Vitamin D concentrations were associated with a composite of in-hospital death, serious infections, and serious cardiovascular events in patients recovering from noncardiac surgery. While causality cannot be determined from our retrospective analysis, the association suggests that a large randomized trial of preoperative vitamin D supplementation and postoperative outcomes is warranted.

Evaluation of vitamin D level in patients from neurosurgical intensive care unit

Vitamin D plays an important role in maintaining normal bone metabolism. Recent studies have suggested that vitamin D influences many other physiological processes, including muscle function, cardiovascular homeostasis, nerve function, and immune response. Furthermore, accumulated evidence suggests that vitamin D also mediates the immune system response to infection. Critical neurosurgical patients have higher infection and mortality rates. To correlate vitamin D deficiency to the immunological status of neurosurgical intensive care unit patients, we detected serum vitamin D level in 15 patients with clinically suspected infection and 10 patients with confirmed infection. Serum level of 25-hydroxyvitamin D, the primary circulating form of vitamin D, was significantly decreased in patients with suspected or confirmed infection after a 2-week neurosurgical intensive care unit hospitalization, while serum level of 1,25-dihydroxyvitamin D, the active form of vitamin D, was significantly decreased in patients after a 4-week neurosurgical intensive care unit hospitalization. These findings suggest that vitamin D deficiency is linked to the immunological status of neurosurgical intensive care unit patients and vitamin D supplementation can improve patient's immunological status.

Deficiency in 25-hydroxyvitamin D and 30-day mortality in patients with severe sepsis and septic shock

BACKGROUND

Vitamin D has immunomodulating properties.

OBJECTIVE

To determine if vitamin D deficiency within 30 days of admission to the intensive care unit in patients with sepsis might be associated with increased all-cause 30-day mortality.

METHODS

In a retrospective cohort study at a large, tertiary, urban, academic medical center, records of patients who had 25-hydroxyvitamin D levels measured within 30 days of admission for severe sepsis or septic shock from June 2006 to April 2011 were examined. Patients were considered deficient in vitamin D if its serum concentration was 15 ng/mL or less. The primary outcome of interest was 30-day mortality.

RESULTS

Among the 121 patients in the sample, 65 (54%) were vitamin D deficient. Baseline demographics were similar between vitamin D deficient and nondeficient groups, except that the vitamin D deficient group had more African Americans (P = .01). All-cause 30-day mortality was significantly higher in patients deficient in vitamin D (37% vs 20%; P = .04) and remained higher at 90 days (51% vs 25%, P = .005). In multivariate analysis, age (odds ratio, 1.04; 95% CI 1.01-1.07; P = .01) and vitamin D deficiency (odds ratio, 2.7; 95% CI, 1.39-18.8; P = .02) were independently associated with increased 30-day mortality.

CONCLUSION

Patients deficient in vitamin D within 30 days of hospital admission for severe sepsis or septic shock may be at increased risk for all-cause 30-day mortality.

Vitamin D and the athlete: emerging insights

Interest in Vitamin D has risen considerably recently with many athletes now advised to take daily vitamin D supplements. The reason for this interest is partly not only attributed to the resurgence of the Vitamin D-deficient disease rickets but also due to the discovery of a Vitamin D receptor in many tissues suggesting a more global role for Vitamin D than previously considered. Unlike the other vitamins that are obtained through the diet, Vitamin D is unique since endogenous synthesis following ultraviolet B (UVB) exposure is the predominant route of entry into systemic circulation. Moreover, Vitamin D could be better classed as a seco-steroid, given that its structure is similar to that of a steroid, and its production is derived from a cholesterol precursor (7-dehydrocholesteol) in the skin. The classification of Vitamin D status is currently subject to considerable debate with many authors opposing governing body recommendations. Regardless of the suggested optimal concentration, there is now growing evidence to suggest that many athletes are in fact Vitamin D deficient, especially in the winter months largely as a consequence of inadequate sun exposure, combined with poor dietary practices, although the consequences of such deficiencies are still unclear in athletic populations. Impaired muscle function and reduced regenerative capacity, impaired immune function, poor bone health and even impaired cardiovascular function have all been associated with low Vitamin D in athletes, however, to date, the majority of studies on Vitamin D have described associations and much more research is now needed examining causation.

Human cathelicidin production by the cervix

hCAP18/LL-37 is the sole human cathelicidin; a family of host defence peptides with key roles in innate host defence. hCAP18/LL-37 is expressed primarily by neutrophils and epithelial cells, but its production and function in the lower genital tract is largely uncharacterised. Despite the significant roles for cathelicidin in multiple organs and inflammatory processes, its impact on infections that could compromise fertility and pregnancy is unknown. The aim of this study was to investigate cathelicidin production, regulation and function in the cervix. hCAP18/LL-37 was found to be present in cervicovaginal secretions collected from women in the first trimester of pregnancy and to be expressed at significantly higher levels in samples from women with alterations in vaginal bacterial flora characteristic of bacterial vaginosis. In endocervical epithelial cell lines, expression of the gene encoding hCAP18/LL-37 (CAMP) was not affected by TLR agonists, but was found to be up-regulated by both 1, 25 hydroxyvitamin D₃ and 25 hydroxyvitamin D₃. However, no association was found between serum levels of vitamin D and hCAP18/LL-37 concentrations in cervicovaginal secretions (n = 116). Exposure to synthetic LL-37 had a pro-inflammatory effect on endocervical epithelial cell lines, increasing secretion of inflammatory cytokine IL-8. Together these data demonstrate inducible expression of hCAP18/LL-37 in the female lower reproductive tract in vivo and suggest the capacity for this peptide to modulate host defence to infection in this system. Further investigation will elucidate the effects of hCAP18/LL-37 on the physiology and pathophysiology of labour, and may lead to strategies for the prevention of infection-associated preterm birth.

Cathelicidin rCRAMP stimulates rat mast cells to generate cysteinyl leukotrienes, synthesize TNF and migrate: involvement of PLC/A2, PI3K and MAPK signaling pathways

Cathelicidins represent a family of cationic peptides involved in host defense systems. Apart from exerting direct anti-microbial effects, cathelicidins can regulate immune responses by affecting the activity of cells playing a role in antibacterial defense. Taking into account that mast cells are critical components of host defense, the aim of this study was to determine whether rat cathelicidin-related anti-microbial peptide (rCRAMP) can influence mast cell activity. We have demonstrated that activation of fully mature rat mast cells with rCRAMP resulted in generation and release of cysteinyl leukotrienes (cysLTs). However, rCRAMP failed to induce mast cell degranulation and histamine release. We also found that rCRAMP stimulated rat mast cells to synthesize TNF, but not CXCL8. What is more, this peptide induced GM-CSF, IL-1β, CCL2 and CCL3 but not IL-33 mRNA expression in mast cells. Finally, we showed that this cathelicidin serves as potent chemoattractant for rat mast cells. rCRAMP-mediated cysLT synthesis and mast cell migration were strongly inhibited by IL-10 pre-treatment. With the use of specific inhibitors, we established that activation of PLC/A2 and ERK1/2, but not p38, was required for rCRAMP-induced mast cell stimulation, while PI3K-dependent pathway is involved in both TNF synthesis and mast cell migration. Our results suggest that cathelicidins can amplify inflammatory responses by causing mast cells accumulation and by stimulating these cells to release potent pro-inflammatory mediators.

LL-37 concentrations and the relationship to vitamin D, immune status, and inflammation in HIV-infected children and young adults

Antimicrobial peptide LL-37 is produced in response to active vitamin D to exert immunomodulatory effects and inhibits HIV replication in vitro. To date, no studies have investigated LL-37 in HIV-infected patients. This study sought to investigate LL-37 and the relationship to 25-hydroxyvitamin D [25(OH)D] and HIV-related variables in this population. HIV-infected subjects and healthy controls ages 1-25 years old were prospectively enrolled in this cross-sectional study. Fasting plasma LL-37 and 25(OH)D concentrations were measured in duplicate with ELISA. HIV(+) subjects (36 antiretroviral therapy (ART)-experienced subjects; 27 ART-naïve subjects) and 31 healthy controls were enrolled. Overall, 93% were black and the median age was 20 years. There was no difference in median (interquartile range) LL-37 between the HIV-infected group and controls [58.3 (46.4,69.5) vs. 51.3 (40.8,98.2) ng/ml, respectively; p=0.57]; however, the ART-experienced group had higher concentrations than the ART-naive group [66.2 (55.4,77.0) vs. 48.9 (38.9,57.9) ng/ml, respectively; p<0.001]. LL-37 was positively correlated with 25(OH)D in controls, but not in HIV-infected groups, and was positively correlated with current CD4 and ΔCD4 (current-nadir) in the ART-experienced group. After adjustment for age, race, sex, and HIV duration, the association between LL-37 and CD4 remained significant. These findings suggest that HIV and/or HIV-related variables may alter the expected positive relationship between vitamin D and LL-37 and should be further investigated.

Vitamin D level and risk of community-acquired pneumonia and sepsis

Previous research has reported reduced serum 25-hydroxyvitamin D (25(OH)D) levels is associated with acute infectious illness. The relationship between vitamin D status, measured prior to acute infectious illness, with risk of community-acquired pneumonia (CAP) and sepsis has not been examined. Community-living individuals hospitalized with CAP or sepsis were age-, sex-, race-, and season-matched with controls. ICD-9 codes identified CAP and sepsis; chest radiograph confirmed CAP. Serum 25(OH)D levels were measured up to 15 months prior to hospitalization. Regression models adjusted for diabetes, renal disease, and peripheral vascular disease evaluated the association of 25(OH)D levels with CAP or sepsis risk. A total of 132 CAP patients and controls were 60 ± 17 years, 71% female, and 86% Caucasian. The 25(OH)D levels <37 nmol/L (adjusted odds ratio (OR) 2.57, 95% CI 1.08-6.08) were strongly associated with increased odds of CAP hospitalization. A total of 422 sepsis patients and controls were 65 ± 14 years, 59% female, and 91% Caucasian. The 25(OH)D levels <37 nmol/L (adjusted OR 1.75, 95% CI 1.11-2.77) were associated with increased odds of sepsis hospitalization. Vitamin D status was inversely associated with risk of CAP and sepsis hospitalization in a community-living adult population. Further clinical trials are needed to evaluate whether vitamin D supplementation can reduce risk of infections, including CAP and sepsis.

Plasma LL-37 correlates with vitamin D and is reduced in human immunodeficiency virus-1 infected individuals not receiving antiretroviral therapy

Low levels of the vitamin D-regulated antimicrobial peptide cathelicidin (LL-37) may negatively impact the immune status of human immunodeficiency virus-1 (HIV-1) infected individuals (HIV+). We compared plasma LL-37 levels in healthy controls (HIV-) and HIV+ individuals on or off antiretroviral therapies (ARTs) (ART+ and ART-, respectively), and evaluated the relationship between vitamin D and LL-37 levels. In this cross-sectional study, levels of LL-37, 25-hydroxycholecalciferol [25(OH)D3] and 1,25-dihydroxycholecalciferol [1,25(OH)2D3] were measured from an initial cohort of 18 healthy controls and 10 HIV+/ART- individuals. Because this cohort lacked HIV+/ART+ subjects, LL-37 was also quantified from a second cohort of 10 HIV+/ART- and 13 HIV+/ART+ individuals. LL-37 levels were significantly lower in the HIV+/ART- group compared to the healthy controls (P = 0.01). A direct relationship was observed between LL-37 and both 25(OH)D3 and 1,25(OH)2D3. The level of 25(OH)D3 was predictive of higher LL-37 (P = 0.04) and for any given level of 25(OH)D3, HIV+/ART- subjects averaged 20 % lower LL-37 compared to the healthy controls (P = 0.045). For any given level of 1,25(OH)2D3, HIV+/ART- subjects averaged 25% lower LL-37 compared to the healthy controls (P = 0.018), although 1,25(OH)2D3 was not predictive of higher LL-37 (P = 0.28). Finally, LL-37 levels were significantly lower in the HIV+/ART- group compared to the HIV+/ART+ group from the second cohort (P = 0.045). Untreated HIV infection may contribute to lower LL-37 levels, independent of vitamin D levels. ART treatment may potentially mitigate this decrease in LL-37 levels.

Diagnostic Value of 25-Hydroxyvitamin D Level and New Cytokines in Neonatal Sepsis

The aim of this study was to evaluate diagnostic value of 25-hydroxyvitamin D level, Upar, IL-33 and ST2 in comparison with C-reactive protein, TNF-α and Interleukin-6 in neonatal sepsis. A total of 106 term babies were included 20 of whom were the control group. We used only data of high probable sepsis with blood culture positive infants, therefore 46 infants were excluded. Blood was collected from infants from the first day of sepsis (1.value) and 48–72 hours later (2.value). There were significant differences between the controls and sepsis (1.value) for 25-hydroxyvitamin D levels (35±19ng/ml and 69±7.5ng/ml, p=0.01), for IL-33 levels (90±34 ng/ml and 412±170 ng/ml, p=0.01), for sST2 levels (453±44 ng/ml and 4120±2720ng/ml, p=0.01), for sUpar levels (2.1±1.3 ng/ml and 11.4 ± 5.2 ng/ml, p=0.01), respectively. There were significant differences between sepsis (1.value) and sepsis (2.value.) with reference to 25-hydroxyvitamin D, IL-33, sST2, and suPAR levels, respectively. In the light of these results, it may be suggested that 25-hydroxyvitamin D level, upar, IL-33 and ST2 can be used as an acute phase reactant like C-reactive protein, TNF-α and Interleukin-6 in diagnosis of neonatal sepsis.

Vitamin D Binding Protein Impact on 25-Hydroxyvitamin D Levels under Different Physiologic and Pathologic Conditions

There is a high prevalence of vitamin D deficiency worldwide, but how to define vitamin D deficiency is controversial. Currently, the plasma concentration of total 25-hydroxyvitamin D [25(OH)D] is considered an indicator of vitamin D status. The free hormone hypothesis states that protein-bound hormones are inactive while unbound hormones are free to exert biological activity. The majority of circulating 25(OH)D and 1,25(OH)2D is tightly bound to vitamin D binding protein (DBP), 10-15% is bound to albumin, and less than 1% of circulating vitamin D exists in an unbound form. While DBP is relatively stable in most healthy populations, a recent study showed that there are gene polymorphisms associated with race and ethnicity that could alter DBP levels and binding affinity. Furthermore, in some clinical situations, total vitamin D levels are altered and knowing whether DBP is also altered may have treatment implications. The aim of this review is to assess DBP concentration in different physiological and pathophysiological conditions. We suggest that DBP should be considered in the interpretation of 25(OH)D levels.

Impact of vitamin D on immune function: lessons learned from genome-wide analysis

Immunomodulatory responses to the active form of vitamin D (1,25-dihydroxyvitamin D, 1,25D) have been recognized for many years, but it is only in the last 5 years that the potential role of this in normal human immune function has been recognized. Genome-wide analyses have played a pivotal role in redefining our perspective on vitamin D and immunity. The description of increased vitamin D receptor (VDR) and 1α-hydroxylase (CYP27B1) expression in macrophages following a pathogen challenge, has underlined the importance of intracrine vitamin D as key mediator of innate immune function. It is now clear that both macrophages and dendritic cells (DCs) are able to respond to 25-hydroxyvitamin D (25D), the major circulating vitamin D metabolite, thereby providing a link between the function of these cells and the variations in vitamin D status common to many humans. The identification of hundreds of primary 1,25D target genes in immune cells has also provided new insight into the role of vitamin D in the adaptive immune system, such as the modulation of antigen-presentation and T cells proliferation and phenotype, with the over-arching effects being to suppress inflammation and promote immune tolerance. In macrophages 1,25D promotes antimicrobial responses through the induction of antibacterial proteins, and stimulation of autophagy and autophagosome activity. In this way variations in 25D levels have the potential to influence both innate and adaptive immune responses. More recent genome-wide analyses have highlighted how cytokine signaling pathways can influence the intracrine vitamin D system and either enhance or abrogate responses to 25D. The current review will discuss the impact of intracrine vitamin D metabolism on both innate and adaptive immunity, whilst introducing the concept of disease-specific corruption of vitamin D metabolism and how this may alter the requirements for vitamin D in maintaining a healthy immune system in humans.

Association between preoperative 25-hydroxyvitamin D level and hospital-acquired infections following Roux-en-Y gastric bypass surgery

IMPORTANCE

Postoperative hospital-acquired infections (HAIs) may result from disruption of natural barrier sites. Recent studies have linked vitamin D status and barrier site integrity.

OBJECTIVE

To investigate the association between preoperative vitamin D status and the risk for HAIs.

DESIGN, SETTING, AND PARTICIPANTS

A retrospective analysis was performed using propensity score methods to construct a matched-pairs cohort to reduce baseline differences between patients with 25-hydroxyvitamin D (25[OH]D) levels less than 30 ng/mL vs 30 ng/mL or greater. Multivariable logistic regression analysis was then performed to examine the association between 25(OH)D levels and HAIs while adjusting for additional perioperative factors. Locally weighted scatterplot smoothing was used to depict the relationship between increasing 25(OH)D levels and the risk for HAIs. This study was conducted in a single, teaching hospital in Boston, Massachusetts, and involved 770 gastric bypass surgery patients between January 1, 2007, and December 31, 2011.

EXPOSURES

Preoperative 25(OH)D levels.

MAIN OUTCOMES AND MEASURES

Association between preoperative 25(OH)D levels and the risk for postoperative HAIs.

RESULTS

The risk for HAIs was 3-fold greater (adjusted odds ratio, 3.05; 95% CI, 1.34-6.94) in patients with 25(OH)D levels less than 30 ng/mL vs 30 ng/mL or greater. Further adjustment for additional perioperative factors did not materially change this association. Locally weighted scatterplot smoothing analysis depicted a near inverse linear relationship between vitamin D status and the risk for HAIs for 25(OH)D levels around 30 ng/mL.

CONCLUSIONS AND RELEVANCE

In our patient cohort, a significant inverse association was observed between preoperative 25(OH)D levels and the risk for HAIs. These results suggest that preoperative 25(OH)D levels may be a modifiable risk factor for postoperative nosocomial infections. Prospective studies must determine whether there is a potential benefit to preoperative optimization of vitamin D status.

Potential benefits of vitamin D supplementation in critically ill patients

AIM

To review potential benefits of vitamin D supplementation in critically ill patients.

METHODS

The data were collected by searching Scopus, PubMed/Medline, ScienceDirect, Clinical trials and Cochrane database systematic reviews. The keywords used as search terms were 'vitamin D', 'critically ill patients', 'ICU' and 'sepsis'.

RESULTS & CONCLUSION

Vitamin D deficiency is common in patients admitted to emergency departments, medical and surgical intensive care units. Positive effects of vitamin D on the immune system through decreasing inflammatory cytokines and increasing natural anti-infective molecules have been reported. Patients with low serum vitamin D concentrations experienced longer hospital stay and were more prone to nosocomial infections, including blood stream and respiratory infections. However, a correlation between vitamin D serum level and patients' mortality is not fully described. Limited studies have assessed effects of vitamin D supplementation on morbidity and mortality in critically ill patients. In the future, well-designed randomized clinical trials should describe the best dose, route and duration of vitamin D supplementation in critically ill patients.

Vitamin D status and its association with season, hospital and sepsis mortality in critical illness

Introduction

Vitamin D plays a key role in immune function. Deficiency may aggravate the incidence and outcome of infectious complications in critically ill patients. We aimed to evaluate the prevalence of vitamin D deficiency and the correlation between serum 25-hydroxyvitamin D (25(OH) D) and hospital mortality, sepsis mortality and blood culture positivity.

Methods

In a single-center retrospective observational study at a tertiary care center in Graz, Austria, 655 surgical and nonsurgical critically ill patients with available 25(OH) D levels hospitalized between September 2008 and May 2010 were included. Cox regression analysis adjusted for age, gender, severity of illness, renal function and inflammatory status was performed. Vitamin D levels were categorized by month-specific tertiles (high, intermediate, low) to reflect seasonal variation of serum 25(OH) D levels.

Results

Overall, the majority of patients were vitamin D deficient (<20 ng/ml; 60.2%) or insufficient (≥20 and <30 ng/dl; 26.3%), with normal 25(OH) D levels (>30 ng/ml) present in only 13.6%. The prevalence of vitamin D deficiency and mean 25(OH) D levels was significantly different in winter compared to summer months (P <0.001). Hospital mortality was 20.6% (135 of 655 patients). Adjusted hospital mortality was significantly higher in patients in the low (hazard ratio (HR) 2.05, 95% confidence interval (CI) 1.31 to 3.22) and intermediate (HR 1.92, 95% CI 1.21 to 3.06) compared to the high tertile. Sepsis was identified as cause of death in 20 of 135 deceased patients (14.8%). There was no significant association between 25(OH) D and C-reactive protein (CRP), leukocyte count or procalcitonin levels. In a subgroup analysis (n = 244), blood culture positivity rates did not differ between tertiles (23.1% versus 28.2% versus 17.1%, P = 0.361).

Conclusions

Low 25(OH) D status is significantly associated with mortality in the critically ill. Intervention studies are needed to investigate the effect of vitamin D substitution on mortality and sepsis rates in this population.

Vitamin D deficiency and risk of acute lung injury in severe sepsis and severe trauma: a case-control study

Background

The aim of this study was to determine the association between 25-hydroxyvitamin D (25-OHD) levels at the onset of critical illness and the development of acute lung injury/acute respiratory distress syndrome (ALI/ARDS) in patients with sepsis or trauma.

Methods

We performed two nested case-control studies of 478 patients with sepsis and trauma with or without ALI/ARDS admitted to the medical, surgical and trauma ICUs of a tertiary-care center. Cases consisted of patients with either sepsis or trauma and ALI/ARDS; controls consisted of equivalent numbers of matched patients with either sepsis or trauma alone. We measured serum 25-OHD levels the morning after ICU admission and used multivariable regression to assess the relationship between 25-OHD and diagnosis of ALI/ARDS during the first four ICU days, controlling for age, gender, diabetes, smoking status and season.

Results

25-OHD levels did not differ between cases with ALI/ARDS and controls in either the sepsis or trauma cohorts. Using a conditional logistic regression model, sepsis patients during the winter season with higher 25-OHD levels were more likely to develop acute lung injury (odds ratio 1.68, 95% confidence interval of 1.05 to 2.69, P = 0.03). This association did not hold for the trauma cohort in either season. Sepsis and trauma patients had a lower risk of hospital mortality at higher 25-OHD levels but neither relationship reached significance. Higher one-year mortality after trauma was associated with lower 25-OHD levels (HR 0.50, CI 0.35,0.72 P = 0.001).

Conclusions

Serum 25-OHD measured early after admission to intensive care is not associated with the development of acute lung injury, hospital or one-year mortality in critically ill patients with sepsis although lower 25-OHD levels were associated with higher one-year mortality in patients with severe trauma.

Association of low serum 25-hydroxyvitamin D levels and sepsis in the critically ill

OBJECTIVE

We hypothesized that deficiency in 25-hydroxyvitamin D prior to hospital admission would be associated with sepsis in the critically ill.

DESIGN

Two-center observational study of patients treated in medical and surgical ICUs.

SETTING

Two hundred nine medical and surgical intensive care beds in two teaching hospitals in Boston, MA.

PATIENTS

Three thousand three hundred eighty-six patients, 18 years old or older, in whom 25-hydroxyvitamin D was measured prior to hospitalization between 1998 and 2011.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

: Preadmission 25-hydroxyvitamin D was categorized as deficiency in 25-hydroxyvitamin D (≤ 15 ng/mL), insufficiency (15-30 ng/mL), and sufficiency (≥ 30 ng/mL). The primary outcome was sepsis as defined by International Classification of Diseases, 9th Edition, Clinical Modification and validated by the 2001 Society of Critical Care Medicine/European Society of Intensive Care Medicine, American College of Chest Physicians, American Thoracic Society, and Surgical Infection Society international sepsis definitions conference guidelines. Logistic regression examined the presence of sepsis 3 days prior to critical care initiation to 7 days after critical care initiation. Adjusted odds ratios were estimated by multivariable logistic regression models. Preadmission 25-hydroxyvitamin D deficiency is predictive for the risk of sepsis. In the full cohort, 25-hydroxyvitamin D deficiency is a significant predictor for the risk of International Classification of Diseases, 9th Edition, Clinical Modification-defined sepsis following multivariable adjustment, including age, gender, race, type (surgical vs medical), and Deyo-Charlson index (adjusted odds ratio, 1.51 [95% CI, 1.17-1.94]; p = 0.001) relative to patients with 25-hydroxyvitamin D sufficiency. In a subset of cohort patients enriched for those with International Classification of Diseases, 9th Edition, Clinical Modification-diagnosed sepsis (n = 444), preadmission 25-hydroxyvitamin D deficiency is a significant predictor for the risk of conference guideline-defined sepsis following multivariable adjustment, including age, gender, race, type (surgical vs medical), and Acute Physiology and Chronic Health Evaluation II (adjusted odds ratio, 2.05 [95% CI, 1.19-3.52]; p = 0.009) relative to patients with 25-hydroxyvitamin D sufficiency. Furthermore, in cohort patients with International Classification of Diseases, 9th Edition, Clinical Modification-defined sepsis (n = 568), the multivariable adjusted risk of 90-day mortality was 1.6-fold higher in those with preadmission 25-hydroxyvitamin D values in the insufficient and deficient range, compared with those with preadmission vitamin D sufficiency (adjusted odds ratio, 1.63 [95% CI, 1.11-2.39]; p = 0.01).

CONCLUSION

25-hydroxyvitamin D deficiency prior to hospital admission is a significant predictor of sepsis in the critically ill. Additionally, patients with sepsis who are not vitamin D sufficient have an increased risk of mortality following critical care initiation.

Association between prehospital vitamin D status and hospital-acquired Clostridium difficile infections

OBJECTIVE

To investigate whether preadmission 25-hydroxyvitamin D (25(OH)D) levels are associated with the risk of hospital-acquired Clostridium difficile infection (HACDI).

MATERIALS AND METHODS

Our retrospective cohort study focused on 568 adult patients from 2 Boston teaching hospitals between August 1993 and November 2006. All patients had 25(OH)D levels measured before hospitalization and were at risk for HACDI (defined as the presence of C difficile toxin A or B in stool samples obtained >48 hours after hospitalization). We performed multivariable regression analyses to test the association of prehospital 25(OH)D levels with HACDI while adjusting for clinically relevant covariates.

RESULTS

In these 568 patients, mean (SD) 25(OH)D level was 19 (12) ng/mL, and 11% of patients met criteria for incident HACDI. Following adjustment for age, sex, race (nonwhite vs white), patient type (medical vs surgical), and Deyo-Charlson index, patients with 25(OH)D levels <10 ng/mL had higher odds of HACDI (odds ratio [OR], 2.90; 95% confidence interval [CI], 1.01-8.34) compared with patients with 25(OH)D levels ≥30 ng/mL. When patients with HACDI were analyzed relative to a larger patient cohort without HACDI (n = 5047), those with 25(OH)D levels <10 ng/mL (OR, 4.96; 95% CI, 1.84-13.38) and 10-19.9 ng/mL (OR, 3.36; 95% CI, 1.28-8.85) had higher adjusted odds of HACDI compared with patients with 25(OH)D levels ≥30 ng/mL.

CONCLUSIONS

In our cohort of adult patients, vitamin D status before hospital admission was inversely associated with the risk of developing HACDI. These data support the need for randomized, controlled trials to test the role of vitamin D supplementation to prevent HACDI.

Vitamin D deficiency is associated with mortality in patients with advanced liver cirrhosis

BACKGROUND

Chronic liver disease is the fifth most common cause of mortality in Europe. Recently, vitamin D deficiency has been associated with an increased risk of mortality in the general population. As patients with advanced liver disease frequently exhibit vitamin D deficiency, we assessed for a possible association of vitamin D deficiency with survival in a cohort of patients with advanced liver disease.

METHODS

Sixty-five patients with liver cirrhosis (median age, 58 years; range, 19-76 years; 66% male; Child-Pugh stage C, 46%) were included in our prospective single-centre survival study. Serum 25-hydroxyvitamin D concentrations were measured by chemiluminescence immunoassay. The optimal cut-off was determined using receiver operating characteristic (ROC) and Kaplan-Meier analysis. Chi-square statistics and multivariate binary logistic regression analysis were also conducted.

RESULTS

Median serum vitamin D levels were 8·2 ng/mL (range <4·0-95·8 ng/mL). Overall, 48% of patients (31/65) died during a 24-month follow-up period. ROC analysis determined a vitamin D level of 6·0 ng/mL as optimal cut-off for discriminating survivors from nonsurvivors. Kaplan-Meier analysis of survival confirmed low vitamin D levels as significant predictor of death (P = 0·012). Finally, multivariate analysis identified low vitamin D levels (OR = 6·3; 95% CI, 1·2-31·2; P = 0·012) and MELD scores (OR = 1·4; 95% CI, 1·2-1·7; P < 0·001) as independent predictors of survival.

CONCLUSION

Low vitamin D levels are associated with increased mortality in patients with advanced liver disease. Thus, serum levels of vitamin D might represent a critical marker of survival in advanced liver cirrhosis.

Vitamin D and the Immune System from the Nephrologist's Viewpoint

Vitamin D and its analogues are widely used as treatments by clinical nephrologists, especially when treating chronic kidney disease (CKD) patients with secondary hyperparathyroidism. As CKD progresses, the ability to compensate for elevations in parathyroid hormone (PTH) and fibroblast growth factor-23 and for decreases in 1,25(OH)₂D₃ becomes inadequate, which results in hyperphosphatemia, abnormal bone disorders, and extra-skeletal calcification. In addition to its calciotropic effect on the regulation of calcium, phosphate, and parathyroid hormone, vitamin D has many other noncalciotropic effects, including controlling cell differentiation/proliferation and having immunomodulatory effects. There are several immune dysregulations that can be noted when renal function declines. Physicians need to know well both the classical and nonclassical functions of vitamin D. This review is an analysis from the nephrologist's viewpoint and focuses on the relationship between the vitamin D and the immune system, together with vitamin's clinical use to treat kidney diseases.

Vitamin d-binding protein levels in plasma and gingival crevicular fluid of patients with generalized aggressive periodontitis

Vitamin D-binding protein (DBP) is the main transport protein of vitamin D and plays an important role in the immune system and host defenses. The purpose of this study was to measure DBP levels in plasma and gingival crevicular fluid (GCF) of patients with generalized aggressive periodontitis (GAgP), in comparison to healthy controls, with the goal of elucidating the relationship between DBP and GAgP. Fifty-nine GAgP patients and 58 healthy controls were recruited for the study; clinical parameters of probing depths (PD), bleeding index, and attachment loss (AL) were recorded. DBP levels were measured by enzyme-linked immunosorbent assay. From the results, GAgP patients had higher plasma DBP concentrations (P < 0.001) but lower GCF DBP concentrations (P < 0.001) than healthy controls. In GAgP group, after controlling the potential confounders of age, gender, smoking status, and BMI index, GCF DBP concentrations correlated negatively with PD (P < 0.001) and AL (P = 0.009). Within the limits of the study, we concluded that decreased GCF DBP level and increased plasma DBP level are associated with periodontitis.