Vitamin D Deficiency in Human and Murine Sepsis

Vitamin D Supplementation in Critically Ill-Narrative Review

BACKGROUND

Studies have shown a high prevalence of vitamin D deficiency in critically ill patients, and these patients are at higher risk for pneumonia and have increased incidence of sepsis and mortality. In this study, we reviewed available literature from randomized controlled trials (RCTs) on vitamin D supplementation in critically ill patients and summarized the evidence in this narrative review.

METHODS

Randomized controlled trials that included vitamin D supplementation as an intervention were eligible for inclusion. No limits were set regarding vitamin D dosage or route of administration, as well as for primary and secondary outcomes. A search was conducted in MEDLINE via PubMed for eligible RCTs. References from systematic reviews (SRs) and meta-analyses (MAs) were screened, and Clinicaltrials.gov was searched for ongoing studies.

RESULTS

A total of 21 RCTs involving 3166 patients were analyzed. There was a large heterogeneity in terms of patients' characteristics and inclusion criteria. Only six studies included patients with vitamin D levels < 50 nmol/L. Regarding clinically important outcomes, most of the studies did not show differences between the intervention and control group in terms of mortality, intensive care unit (ICU) or hospital length of stay (LoS).

CONCLUSIONS

There is great variability in trial designs regarding the selection of patients, dosage, dosing intervals and routes of administration of vitamin D supplements. Better study designs are mandatory for future clinical research, with measuring and reporting basal vitamin D levels before randomization. Since variability in supplementation regimes limits the possibility of data synthesis, standardized protocols for vitamin D supplementation should be used in clinical trial settings.

11β hydroxysteroid dehydrogenase type 1 transgenic mesenchymal stem cells attenuate inflammation in models of sepsis

Background

Human bone marrow mesenchymal stem cell (MSC) administration reduces inflammation in pre-clinical models of sepsis and sepsis-related lung injury, however clinical efficacy in patients has not yet been demonstrated. We previously showed that Alveolar Macrophage (AM) 11β-hydroxysteroid dehydrogenase type-1 (HSD-1) autocrine signalling is impaired in critically ill sepsis patients, which promotes inflammatory injury. Administration of transgenic MSCs (tMSCs) which overexpress HSD-1 may enhance the anti-inflammatory effects of local glucocorticoids and be more effective at reducing inflammation in sepsis than cellular therapy alone.

Methods

MSCs were transfected using a recombinant lentiviral vector containing the HSD-1 and GPF transgenes under the control of a tetracycline promoter. Thin layer chromatography assessed HSD-1 reductase activity in tMSCs. Mesenchymal stem cell phenotype was assessed by flow cytometry and bi-lineage differentiation. HSD-1 tMSCs were co-cultured with LPS-stimulated monocyte-derived macrophages (MDMs) from healthy volunteers prior to assessment of pro-inflammatory cytokine release. HSD-1 tMSCs were administered intravenously to mice undergoing caecal ligation and puncture (CLP).

Results

MSCs were transfected with an efficiency of 91.1%, and maintained an MSC phenotype. Functional HSD-1 activity was demonstrated in tMSCs, with predominant reductase cortisol activation (peak 8.23 pM/hour/100,000 cells). HSD-1 tMSC co-culture with LPS-stimulated MDMs suppressed TNFα and IL-6 release. Administration of transgene activated HSD-1 tMSCs in a murine model of CLP attenuated neutrophilic inflammation more effectively than transgene inactive tMSCs (medians 0.403 v 1.36 × 106/ml, p = 0.033).

Conclusion

The synergistic impact of HSD-1 transgene expression and MSC therapy attenuated neutrophilic inflammation in a mouse model of peritoneal sepsis more effectively than MSC therapy alone. Future studies investigating the anti-inflammatory capacity of HSD-1 tMSCs in models of sepsis-related direct lung injury and inflammatory diseases are required.

Analysis of alterations in serum vitamins and correlations with gut microbiome, microbial metabolomics in patients with sepsis

BACKGROUND

Vitamins are essential micronutrients that play key roles in many biological pathways associated with sepsis. The gut microbiome plays a pivotal role in the progression of sepsis and may contribute to the onset of multi-organ dysfunction syndrome (MODS). The aim of this study was to investigate the changes in serum vitamins, and their correlation with intestinal flora and metabolomic profiles in patients with sepsis.

METHODS

The serum levels of vitamins were determined by Ultra Performance Liquid Chromatography (UPLC). 16S rRNA gene sequencing and Liquid Chromatography-tandem Mass Spectrometry (LC-MS/MS) targeted metabolomics were used for microbiome and metabolome analysis.

RESULTS

In the training cohort: After univariate, multivariate (OPLS-DA) and Spearman analyses, it was concluded that vitamin levels of 25 (OH) VD3 and (VD2 + VD3), as well as vitamins A and B9, differed significantly among healthy controls (HC), non-septic critical patients (NS), and sepsis patients (SS) (P < 0.05). The validation cohort confirmed the differential vitamin findings from the training cohort. Moreover, analyses of gut flora and metabolites in septic patients and healthy individuals revealed differential flora, metabolites, and metabolic pathways that were linked to alterations in serum vitamin levels. We found for the first time that vitamin B9 was negatively correlated with g_Sellimonas.

CONCLUSION

Sepsis patients exhibited significantly lower levels of 25 (OH) VD3 and (VD2 + VD3), vitamins A and B9, which hold potential as predictive markers for sepsis prognosis. The changes in these vitamins may be associated with inflammatory factors, oxidative stress, and changes in gut flora.

Should I Supplement Vitamin D in a Patient With Sepsis?

Sepsis is a potentially fatal organ failure produced by the host's immune response to infection. It is critical to identify risk factors associated with a poor prognosis in septic patients in order to develop new therapy options. Vitamin D deficiency (25-hydroxyvitamin cholecalciferol < 20 ng/mL) is common in critical and septic patients. Serum vitamin D concentrations are associated with an increased incidence of mortality in critically ill adult patients. In critically ill patients, vitamin D supplementation (a very high vitamin D 3 or cholecalciferol loading dosage as a single bolus dose ranging from 400,000 to 540,000 IU) is feasible and safe. Some of the trials and their post-hoc analyses evaluating vitamin D supplementation in severely sick individuals, including septic patients, suggested possible benefits in mortality (reduced 28-day mortality in the range of 8.1%-17.5%), and other outcomes (reduction in hospital length in the range from 9 to 18 days, and decrease in duration of mechanical ventilation in the range from 5 to 10 days). Despite the fact that many studies support the provision of vitamin D to septic patients, there are still many studies that contradict this opinion, and there is still debate about the recommendation to use vitamin D in sepsis. A pragmatic clinical approach in severe sepsis could be supplementation of vitamin D if serum levels are diminished (< 30 ng/mL). It appears that a single ultrahigh dose of vitamin D 3 (cholecalciferol) could be administered to the septic patient via an enteral tube, followed by daily or monthly maintenance doses. Parenteral administration might be reserved for a subgroup of septic patients with gastrointestinal, hepatic, or renal dysfunction. Future clinical trials designed exclusively for septic patients are required to assess the potential advantages of vitamin D. Possible impacts of selective activators of vitamin D receptors, such as paricalcitol, should be elucidated in sepsis. This emphasizes the requirement for more study and confirmation of any potential beneficial effects of vitamin D in sepsis.

Calcitriol attenuates poly(I:C)-induced lung injury in obese mice via modulating toll-like receptor 3- and renin-angiotensin system-associated signal pathways

This study investigated the effects of calcitriol on polyinosinic-polycytidylic acid (poly(I:C))-induced acute lung injury (ALI) and its association with Toll-like receptor 3 (TLR3) and renin-angiotensin system (RAS) signal pathways in obese mice. Normal mice were fed a high-fat diet to induce obesity. Obese mice were divided into four groups: SS group, intratracheally instilled with saline and intravenous (IV) saline injection via tail vein; SD group, instilled with saline and IV calcitriol injection; PS group, instilled with poly(I:C) and IV saline injection; and PD group, instilled with poly(I:C) and IV calcitriol injection. All mice were sacrificed 12 or 24 h after poly(I:C) stimulation. The results showed that poly(I:C) instillation led to increased production of systemic inflammatory cytokines. In the lungs, the population of macrophages decreased, while more neutrophils were recruited. TLR3-associated genes including IRF3, nuclear factor-κB, interferon-β and phosphorylated IRF3 expression levels, were upregulated. The RAS-associated AT1R and ACE2 protein levels increased, whereas AT2R, Ang(1-7), and MasR levels decreased. Also, reduced tight junction (TJ) proteins and elevated lipid peroxide levels were observed 24 h after poly(I:C) stimulation. Compared to the PS group, the PD group exhibited reduced systemic and lung inflammatory cytokine levels, increased macrophage while decreased neutrophil percentages, downregulated TLR3-associated genes and phosphorylated IRF3, and polarized toward the RAS-AT2R/Ang(1-7)/MasR pathway in the lungs. Higher lung TJ levels and lower injury scores were also noted. These findings suggest that calcitriol treatment after poly(I:C) instillation alleviated ALI in obese mice possibly by downregulating TLR3 expression and tending toward the RAS-associated anti-inflammatory pathway.

Update on vitamin D role in severe infections and sepsis

Severe infections frequently require admission to the intensive care unit and cause life-threatening complications in critically ill patients. In this setting, severe infections are acknowledged as prerequisites for the development of sepsis, whose pathophysiology implies a dysregulated host response to pathogens, leading to disability and mortality worldwide.Vitamin D is a secosteroid hormone that plays a pivotal role to maintain immune system homeostasis, which is of paramount importance to resolve infection and modulate the burden of sepsis. Specifically, vitamin D deficiency has been widely reported in critically ill patients and represents a risk factor for the development of severe infections, sepsis and worse clinical outcomes. Several studies have demonstrated the feasibility, safety and effectiveness of vitamin D supplementation strategies to improve vitamin D body content, but conflictual results support its benefit in general populations of critically ill patients. In contrast, small randomised clinical trials reported that vitamin D supplementation may improve host-defence to pathogen invasion via the production of cathelicidin and specific cytokines. Nonetheless, no large scale investigations have been designed to specifically assess the impact of vitamin D supplementation on the outcome of critically ill septic patients admitted to the intensive care unit.

Modulation of the vitamin D receptor by traditional Chinese medicines and bioactive compounds: potential therapeutic applications in VDR-dependent diseases

The Vitamin D receptor (VDR) is a crucial nuclear receptor that plays a vital role in various physiological functions. To a larger extent, the genomic effects of VDR maintain general wellbeing, and its modulation holds implications for multiple diseases. Current evidence regarding using vitamin D or its synthetic analogs to treat non-communicable diseases is insufficient, though observational studies suggest potential benefits. Traditional Chinese medicines (TCMs) and bioactive compounds derived from natural sources have garnered increasing attention. Interestingly, TCM formulae and TCM-derived bioactive compounds have shown promise in modulating VDR activities. This review explores the intriguing potential of TCM and bioactive compounds in modulating VDR activity. We first emphasize the latest information on the genetic expression, function, and structure of VDR, providing a comprehensive understanding of this crucial receptor. Following this, we review several TCM formulae and herbs known to influence VDR alongside the mechanisms underpinning their action. Similarly, we also discuss TCM-based bioactive compounds that target VDR, offering insights into their roles and modes of action.

Association of vitamin D receptor gene polymorphism with the risk of sepsis: A systematic review and meta-analysis

BACKGROUND

To investigate the association between sepsis and the vitamin D receptor (VDR) gene polymorphisms.

METHODS

Databases including PubMed, Cochrane Library, EMbase, CNKI, Wanfang Data, and VIP Data were systematically searched. The association was assessed using odds ratios (ORs), and 95% confidence intervals (CIs). The statistical tests were performed using Review Manager 5.4.

RESULTS

We identified a total of 5 studies. The relationship between VDR gene polymorphisms (Apa I, Bsm I, Taq I, and Fok I), and incidence of sepsis was investigated. The results of this meta-analysis showed that the allelic contrast model (F vs f, P = .03, OR = 0.65, 95% CI = 0.44-0.95), dominant genetic model (FF vs Ff + ff, P = .02, OR = 0.53, 95% CI = 0.30-0.91), and codominance genetic model (FF vs ff, P = .03, OR = 0.39, 95% CI = 0.16-0.91) of VDR Fok I locus increased the risk of sepsis, and the lack of association between the VDR Fok I gene polymorphism and the risk assessment of sepsis, based on the ethnic subgroup analysis, might be attributable to the small sample size. The risk of sepsis with Apa I, Bsm I, and Taq I did not appear to be correlated.

CONCLUSION SUBSECTIONS

This meta-analysis revealed that the VDR Fok I polymorphism is closely associated with the susceptibility to sepsis, and patients with sepsis have lower 25-hydroxyvitamin D levels. VDR Fok I gene mutations may change the risk of sepsis.

Attenuation of homeostatic sleep response and rest-activity circadian rhythm in vitamin D deficient mice

The link between vitamin D deficiency (VDD) and sleep disturbances has long been suggested. However, the direct causality between VDD, sleep disturbances, and circadian rhythm remains unclear. We aimed to characterize sleep-wake behavior and circadian rhythms in an animal model of VDD. VDD was induced by feeding vitamin D-deficient chow, and we analyzed sleep and circadian rhythm parameters. During light period, VDD mice exhibited reduced wake with more frequent wake bouts and increased NREM sleep time. However, during dark period, the wake EEG power spectrum peaked at theta band frequency, and slow-wave energy was suppressed in mice with VDD. Rest-activity analyses revealed increased circadian period, lower wheel counts, and more frequent and short activity bouts during VDD. Combining sleep and circadian data, we found significantly suppressed activities during the hours with a wake duration shorter than 30 minutes. Moreover, mice in VDD state exhibited a negative correlation between wake theta power and hourly wheel-running counts during dark period. Our data point to a direct link between VDD and disturbances in sleep and rest-activity circadian rhythm, featuring frequent wake bouts during the sleeping phase, reduced sleep pressure build-up in dark period, and reduced activity levels due to increased susceptibility to sleepiness.

Impaired alveolar macrophage 11β-hydroxysteroid dehydrogenase type 1 reductase activity contributes to increased pulmonary inflammation and mortality in sepsis-related ARDS

Background

Acute Respiratory Distress Syndrome (ARDS) is a devastating pulmonary inflammatory disorder, commonly precipitated by sepsis. Glucocorticoids are immunomodulatory steroids that can suppress inflammation. Their anti-inflammatory properties within tissues are influenced by their pre-receptor metabolism and amplification from inactive precursors by 11β-hydroxysteroid dehydrogenase type-1 (HSD-1). We hypothesised that in sepsis-related ARDS, alveolar macrophage (AM) HSD-1 activity and glucocorticoid activation are impaired, and associated with greater inflammatory injury and worse outcomes.

Methods

We analysed broncho-alveolar lavage (BAL) and circulating glucocorticoid levels, AM HSD-1 reductase activity and Receptor for Advanced Glycation End-products (RAGE) levels in two cohorts of critically ill sepsis patients, with and without ARDS. AM HSD-1 reductase activity was also measured in lobectomy patients. We assessed inflammatory injury parameters in models of lung injury and sepsis in HSD-1 knockout (KO) and wild type (WT) mice.

Results

No difference in serum and BAL cortisol: cortisone ratios are shown between sepsis patients with and without ARDS. Across all sepsis patients, there is no association between BAL cortisol: cortisone ratio and 30-day mortality. However, AM HSD-1 reductase activity is impaired in patients with sepsis-related ARDS, compared to sepsis patients without ARDS and lobectomy patients (0.075 v 0.882 v 0.967 pM/hr/106 AMs, p=0.004). Across all sepsis patients (with and without ARDS), impaired AM HSD-1 reductase activity is associated with defective efferocytosis (r=0.804, p=0.008) and increased 30-day mortality. AM HSD-1 reductase activity negatively correlates with BAL RAGE in sepsis patients with ARDS (r=-0.427, p=0.017). Following intra-tracheal lipopolysaccharide (IT-LPS) injury, HSD-1 KO mice demonstrate increased alveolar neutrophil infiltration, apoptotic neutrophil accumulation, alveolar protein permeability and BAL RAGE concentrations compared to WT mice. Caecal Ligation and Puncture (CLP) injury in HSD-1 KO mice results in greater peritoneal apoptotic neutrophil accumulation compared to WT mice.

Conclusions

AM HSD-1 reductase activity does not shape total BAL and serum cortisol: cortisone ratios, however impaired HSD-1 autocrine signalling renders AMs insensitive to the anti-inflammatory effects of local glucocorticoids. This contributes to the decreased efferocytosis, increased BAL RAGE concentrations and mortality seen in sepsis-related ARDS. Upregulation of alveolar HSD-1 activity could restore AM function and improve clinical outcomes in these patients.

Association between Vitamin D Levels and Mortality in Sepsis Patients Admitted to an Intensive Care at General Hospital Dr. M. Djamil, West Sumatera, Indonesia

BACKGROUND: Vitamin D deficiency is associated with an increased risk and progression of the disease, especially sepsis. Low serum Vitamin D levels when patients enter the Intensive Care Unit (ICU) can affect patient care outcomes. AIM: This study aims to determine the relationship between Vitamin D levels and sepsis patients’ treatment outcomes in the Intensive Care Unit. METHODS: We analyzed 80 sepsis patients admitted from July 2022 to September 2022. This study used a cohort design. Sampling and collection were carried out from July 2022 to September 2022 in the Intensive Care Unit of Dr. M. Djamil Hospital, Padang. This study was conducted on 40 case samples and 40 control samples. The relationship between Vitamin D levels and treatment outcomes for sepsis patients was analyzed using the Chi-Square/Fisher Exact Test. RESULTS: Patients with the most Vitamin D deficiency were women (77.5%), obese (57.5%), with the most comorbid Chronic Kidney Injury (12.5%), the mean APACHE II score was 21, and SOFA score of 7. Patients with non-deficiency Vitamin D most was male (7%), obese (52.5%), with the most comorbid Cardiovascular Disease (15.0%), the mean APACHE II score was 19, and SOFA score of 5. In 40 patients with Vitamin D deficiency, 24 patients (57.1%) non-survived, and 16 patients (42.1%) survived (RR = 1.833). CONCLUSION: Vitamin D deficiency increases the risk of death in septic patients, so further intervention is needed.

Vitamin D Status and Potential Therapeutic Options in Critically Ill Patients: A Narrative Review of the Clinical Evidence

Vitamin D covers roles of paramount importance in the regulation of multiple physiological pathways of the organism. The metabolism of vitamin D involves kidney-liver crosstalk and requires an adequate function of these organs, where vitamin D is progressively turned into active forms. Vitamin D deficiency has been widely reported in patients living in the community, being prevalent among the most vulnerable subjects. It has been also documented in many critically ill patients upon admission to the intensive care unit. In this context, vitamin D deficiency may represent a risk factor for the development of life-threatening clinical conditions (e.g., infection and sepsis) and worse clinical outcomes. Several researchers have investigated the impact of vitamin D supplementation showing its feasibility, safety, and effectiveness, although conflicting results have put into question its real benefit in critically ill patients. The existing studies included heterogeneous critically ill populations and used slightly different protocols of vitamin D supplementation. For these reasons, pooling up the results is difficult and not conclusive. In this narrative review, we described vitamin D physiology and the pathophysiology of vitamin D depletion with a specific focus on critically ill patients with liver dysfunction, acute kidney injury, acute respiratory failure, and sepsis.

Vitamin D, vitamin D-binding protein, free vitamin D and COVID-19 mortality in hospitalized patients

BACKGROUND

Vitamin D deficiency has been associated with worse coronavirus disease 2019 (COVID-19) outcomes, but circulating 25-hydroxyvitamin D [25(OH)D] is largely bound to vitamin D-binding protein (DBP) or albumin, both of which tend to fall in illness, making the 25(OH)D status hard to interpret. Because of this, measurements of unbound ("free") and albumin-bound ("bioavailable") 25(OH)D have been proposed.

OBJECTIVES

We aimed to examine the relationship between vitamin D status and mortality from COVID-19.

METHODS

In this observational study conducted in Liverpool, UK, hospitalized COVID-19 patients with surplus sera available for 25(OH)D analysis were studied. Clinical data, including age, ethnicity, and comorbidities, were extracted from case notes. Serum 25(OH)D, DBP, and albumin concentrations were measured. Free and bioavailable 25(OH)D were calculated. Relationships between total, free, and bioavailable 25(OH)D and 28-day mortality were analyzed by logistic regression.

RESULTS

There were 472 patients with COVID-19 included, of whom 112 (23.7%) died within 28 days. Nonsurvivors were older (mean age, 73 years; range, 34-98 years) than survivors (mean age, 65 years; range, 19-95 years; P = 0.003) and were more likely to be male (67%; P = 0.02). The frequency of vitamin D deficiency [25(OH)D < 50 nmol/L] was similar between nonsurvivors (71/112; 63.4%) and survivors (204/360; 56.7%; P = 0.15) but, after adjustments for age, sex, and comorbidities, increased odds for mortality were present in those with severe deficiency [25(OH)D < 25 nmol/L: OR, 2.37; 95% CI, 1.17-4.78] or a high 25(OH)D (≥100 nmol/L; OR, 4.65; 95% CI, 1.51-14.34) compared with a 25(OH)D value of 50-74 nmol/L (reference). Serum DBP levels were not associated with mortality after adjustments for 25(OH)D, age, sex, and comorbidities. Neither free nor bioavailable 25(OH)D values were associated with mortality.

CONCLUSIONS

Vitamin D deficiency, as commonly defined by serum 25(OH)D levels (<50 nmol/L), is not associated with increased mortality from COVID-19, but extremely low (<25 nmol/L) and high (>100 nmol/L) levels may be associated with mortality risks. Neither free nor bioavailable 25(OH)D values are associated with mortality risk. The study protocol was approved by the London-Surrey Research Ethics Committee (20/HRA/2282).

Cathepsin S Contributes to Lung Inflammation in Acute Respiratory Distress Syndrome

Rationale: Although the cysteine protease cathepsin S has been implicated in the pathogenesis of several inflammatory lung diseases, its role has not been examined in the context of acute respiratory distress syndrome, a condition that still lacks specific and effective pharmacological treatments. Objectives: To characterize the status of cathepsin S in acute lung inflammation and examine the role of cathepsin S in disease pathogenesis. Methods: Human and mouse model BAL fluid samples were analyzed for the presence and activity of cathepsin S and its endogenous inhibitors. Recombinant cathepsin S was instilled directly into the lungs of mice. The effects of cathepsin S knockout and pharmacological inhibition were examined in two models of acute lung injury. Protease-activated receptor-1 antagonism was used to test a possible mechanism for cathepsin S-mediated inflammation. Measurements and Main Results: Pulmonary cathepsin S concentrations and activity were elevated in acute respiratory distress syndrome, a phenotype possibly exacerbated by the loss of the endogenous antiprotease cystatin SN. Direct cathepsin S instillation into the lungs induced key pathologies of acute respiratory distress syndrome, including neutrophilia and alveolar leakage. Conversely, in murine models of acute lung injury, genetic knockdown and prophylactic or therapeutic inhibition of cathepsin S reduced neutrophil recruitment and protein leakage. Cathepsin S may partly mediate its pathogenic effects via protease-activated receptor-1, because antagonism of this receptor abrogated cathepsin S-induced airway inflammation. Conclusions: Cathepsin S contributes to acute lung injury and may represent a novel therapeutic target for acute respiratory distress syndrome.

Astragalus polysaccharide protects sepsis model rats after cecum ligation and puncture

To investigate the protective effect and mechanism of Astragalus polysaccharide (APS) on septic rats, the present project applied APS at concentrations of 400, 600, and 800 mg/kg/d to rats for prophylactic administration for 7 d, and a rat sepsis model was constructed by the cecum ligation and puncture (CLP) method. Forty-eight rats were divided into six groups of eight each. Each experiment was repeated at least three times. Rat serum levels of VD₃, 25(OH)D₃, 1,25(OH)₂D₃, IL-6, TNF-α, CRP, sICAM-1, corticosterone (CORT), and short-chain fatty acids (SCFAs) in each group were detected, and renal damage was observed by H&E. We also determined the protein expression of CYP27B1, CYP24A1, vitamin D receptor (VDR), steroidogenic acute regulatory protein (STAR), 3β-hydroxysteroid dehydrogenase (3β-HSD), CYP21A2, CYP17A1, and CYP11B1. An operational taxonomic unit (OTU) was used to determine the gut microbiota diversity of septic rats after prophylactic administration and before modeling. Results revealed that APS markedly increased the contents of 25(OH)D₃ and 1,25(OH)₂D₃ but greatly decreased those of TNF-α, IL-6, CRP, sICAM-1, and CORT. APS alleviated renal tubular dilation and vascular congestion in rat kidneys and substantially reduced renal cell apoptosis. Moreover, the expression of CYP24A1, VDR, CYP11B1, CYP21A2, CYP17A1, STAR, and 3β-HSD in the kidneys of the H-APS group was substantially decreased compared to that of the model group, whereas CYP27B1 was markedly increased. GC-MS detection indicated a substantial increase in SCFAs and acetic acid content in the H-APS group versus model group. Through 16S sequencing, the abundance of genus and gut microbiota species increased in the APS groups compared to that of the control group. Taken together, APS increased the activity of the vitamin D axis, inhibited the production of inflammatory factors in the body, altered the structure of rat intestinal flora, and increased the amount of acetic acid and SCFAs in rats, thereby effectively hindering inflammation and organ damage in septic rats.

Rapid and Effective Vitamin D Supplementation May Present Better Clinical Outcomes in COVID-19 (SARS-CoV-2) Patients by Altering Serum INOS1, IL1B, IFNg, Cathelicidin-LL37, and ICAM1

Background: We aimed to establish an acute treatment protocol to increase serum vitamin D, evaluate the effectiveness of vitamin D3 supplementation, and reveal the potential mechanisms in COVID-19. Methods: We retrospectively analyzed the data of 867 COVID-19 cases. Then, a prospective study was conducted, including 23 healthy individuals and 210 cases. A total of 163 cases had vitamin D supplementation, and 95 were followed for 14 days. Clinical outcomes, routine blood biomarkers, serum levels of vitamin D metabolism, and action mechanism-related parameters were evaluated. Results: Our treatment protocol increased the serum 25OHD levels significantly to above 30 ng/mL within two weeks. COVID-19 cases (no comorbidities, no vitamin D treatment, 25OHD <30 ng/mL) had 1.9-fold increased risk of having hospitalization longer than 8 days compared with the cases with comorbidities and vitamin D treatment. Having vitamin D treatment decreased the mortality rate by 2.14 times. The correlation analysis of specific serum biomarkers with 25OHD indicated that the vitamin D action in COVID-19 might involve regulation of INOS1, IL1B, IFNg, cathelicidin-LL37, and ICAM1. Conclusions: Vitamin D treatment shortened hospital stay and decreased mortality in COVID-19 cases, even in the existence of comorbidities. Vitamin D supplementation is effective on various target parameters; therefore, it is essential for COVID-19 treatment.

MicroRNA-122 contributes to lipopolysaccharide-induced acute kidney injury via down-regulating the vitamin D receptor in the kidney

BACKGROUND

Our previous studies showed that vitamin D receptor (VDR) depletion promotes lipopolysaccharide (LPS)-induced acute kidney injury (AKI) in mice, and renal VDR is down-regulated in AKI, but the mechanism of VDR down-regulation is unclear.

METHODS

Nutritional vitamin D deficiency was induced by feeding mice a vitamin D-deficient (VD-D) diet. Mice were injected intraperitoneally with LPS (20 mg/kg) to establish LPS-induced AKI. Levels of VDR and miR-122 were measured both in vivo and in vitro. The associations between VDR and miR-122 were analysed by dual-luciferase reporter assays.

RESULTS

Compared with vitamin D-sufficient (VD-S) mice, VD-D mice developed more severe renal injury following LPS challenge. LPS induced a dramatic decrease in VDR expression and marked induction of miR-122 both in vivo and in vitro. Furthermore, miR-122 hairpin inhibitor alleviated LPS-induced VDR down-regulation whereas miR-122 mimic directly suppressed VDR expression in HK-2 cells. In luciferase reporter assays, miR-122 mimic was able to suppress luciferase activity in 293T cells co-transfected with a luciferase reporter that contains a putative miR-122 target site from 3'UTR of the VDR transcript, but not when this site was mutated. Moreover, miR-122 mimic significantly blocked paricalcitol-induced luciferase activity in 293T cells co-transfected with a VDRE-driven luciferase reporter, whereas miR-122 hairpin inhibitor enhanced paricalcitol's activity to suppress PUMA and caspase 3 activation induced by LPS in HK-2 cells.

CONCLUSIONS

Collectively, these studies provide evidence that miR-122 directly targets VDR in renal tubular cells, which strongly suggest that miR-122 up-regulation in the kidney under LPS challenge contributes to kidney injury by down-regulating VDR expression.

Population-Specific Metabolic Alterations in Professional Antigen-Presenting Cells Contribute to Sepsis-Associated Immunosuppression

Sepsis is a complex host response triggered by an infection, with the patient's immune system between hyper- and hypo-responsiveness being the main reason for the syndromes' development and propagation. Studies conducted in peripheral blood mononuclear cells uncovered an association between an impaired immunometabolism and the severity and outcome of the disease. With this prospective observational study, we aimed to evaluate the immunometabolic phenotype of monocytes and B cells and its association with the cell function.Monocytes and B cells were isolated from patients with sepsis (n = 10; onset, days 4 and 8) and healthy volunteers (n = 10) and subsequently analyzed for metabolic changes and human leukocyte antigen-DR (HLA-DR) expression. Contemporaneously, immune checkpoints on monocytes and the ex vivo cytokine responses (interleukins 6 and 8) upon lipopolysaccharide or zymosan stimulation were analyzed. The distribution of B cell subsets was assessed, and plasma levels of immunoglobulins and tricarboxylic acid cycle intermediates were quantified.Both monocytes and B cells exhibited decreased HLA-DR expression in patients with sepsis. Monocytes displayed a stable upregulated glycolysis while B cells augmented glycolysis and respiration over time. The monocytes' ability to respond to stimulation was stimuli-dependently reduced but recovered over time. The B cell compartment shifted toward antibody-producing subsets and elevated immunoglobulins within the first days.Our results provide evidence for the induction of a state of trained immunity in monocytes and an early but transient immunosuppressive phenotype accounting for peripheral sepsis-induced vulnerability to infections. B cells exhibit an unsustainable activation contributing to adaptive immunosuppression.

Vitamin D and Immune Regulation: Antibacterial, Antiviral, Anti-Inflammatory

Regulation of immune function continues to be one of the most well-recognized extraskeletal actions of vitamin D. This stemmed initially from the discovery that antigen presenting cells such as macrophages could actively metabolize precursor 25-hydroxyvitamin D (25D) to active 1,25-dihydroxyvitamin D (1,25D). Parallel observation that activated cells from the immune system expressed the intracellular vitamin D receptor (VDR) for 1,25D suggested a potential role for vitamin D as a localized endogenous modulator of immune function. Subsequent studies have expanded our understanding of how vitamin D exerts effects on both the innate and adaptive arms of the immune system. At an innate level, intracrine synthesis of 1,25D by macrophages and dendritic cells stimulates expression of antimicrobial proteins such as cathelicidin, as well as lowering intracellular iron concentrations via suppression of hepcidin. By potently enhancing autophagy, 1,25D may also play an important role in combatting intracellular pathogens such as M. tuberculosis and viral infections. Local synthesis of 1,25D by macrophages and dendritic cells also appears to play a pivotal role in mediating T-cell responses to vitamin D, leading to suppression of inflammatory T helper (Th)1 and Th17 cells, and concomitant induction of immunotolerogenic T-regulatory responses. The aim of this review is to provide an update on our current understanding of these prominent immune actions of vitamin D, as well as highlighting new, less well-recognized immune effects of vitamin D. The review also aims to place this mechanistic basis for the link between vitamin D and immunity with studies in vivo that have explored a role for vitamin D supplementation as a strategy for improved immune health. This has gained prominence in recent months with the global coronavirus disease 2019 health crisis and highlights important new objectives for future studies of vitamin D and immune function. © 2020 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

Prevalence and Impact of Vitamin D Deficiency in Critically Ill Cancer Patients Admitted to the Intensive Care Unit

Vitamin D deficiency is frequent in cancer patients and a risk factor for morbidity and mortality during critical illness. This single-center retrospective study analyzed 25-hydroxyvitamin D levels in critically ill cancer patients (n = 178; hematologic, n = 108; solid, n = 70) enrolled in a prospective ICU registry. The primary analysis was the prevalence of vitamin D deficiency (<20 ng/mL) and the severe deficiency (≤12 ng/mL). Secondary analyses included risk factors for vitamin D deficiency and its impact on ICU, hospital, and 1-year mortality. The prevalence of vitamin D deficiency and severe deficiency was 74% (95% CI: 67-80%) and 54% (95% CI: 47-61%). Younger age, relapsed/refractory disease, and a higher sepsis-related organ failure assessment (SOFA) score were independent risk factors for vitamin D deficiency (p < 0.05). After adjusting for relapsed/refractory disease, infection, the SOFA score, and the early need for life-supporting interventions, severe vitamin D deficiency was an independent predictor of hospital mortality (OR: 2.21, 95% CI: 1.03-4.72, p = 0.04) and 1-year mortality (OR: 3.40, 95% CI: 1.50-7.71, p < 0.01), but not of ICU mortality. Conclusion: Vitamin D deficiency is common in critically ill cancer patients requiring ICU admission, but its impact on short-term mortality in this group is uncertain. The observed association of severe vitamin D deficiency with the post-ICU outcome warrants clinical consideration and further study.

Vitamin D and COVID-19: evidence and recommendations for supplementation

Vitamin D is a hormone that acts on many genes expressed by immune cells. Evidence linking vitamin D deficiency with COVID-19 severity is circumstantial but considerable-links with ethnicity, obesity, institutionalization; latitude and ultraviolet exposure; increased lung damage in experimental models; associations with COVID-19 severity in hospitalized patients. Vitamin D deficiency is common but readily preventable by supplementation that is very safe and cheap. A target blood level of at least 50 nmol l-1, as indicated by the US National Academy of Medicine and by the European Food Safety Authority, is supported by evidence. This would require supplementation with 800 IU/day (not 400 IU/day as currently recommended in UK) to bring most people up to target. Randomized placebo-controlled trials of vitamin D in the community are unlikely to complete until spring 2021-although we note the positive results from Spain of a randomized trial of 25-hydroxyvitamin D3 (25(OH)D3 or calcifediol) in hospitalized patients. We urge UK and other governments to recommend vitamin D supplementation at 800-1000 IU/day for all, making it clear that this is to help optimize immune health and not solely for bone and muscle health. This should be mandated for prescription in care homes, prisons and other institutions where people are likely to have been indoors for much of the summer. Adults likely to be deficient should consider taking a higher dose, e.g. 4000 IU/day for the first four weeks before reducing to 800 IU-1000 IU/day. People admitted to the hospital with COVID-19 should have their vitamin D status checked and/or supplemented and consideration should be given to testing high-dose calcifediol in the RECOVERY trial. We feel this should be pursued with great urgency. Vitamin D levels in the UK will be falling from October onwards as we head into winter. There seems nothing to lose and potentially much to gain.

Metabolic and Endocrine Challenges

This review aims to provide an overview of metabolic and endocrine challenges in the setting of intensive care medicine. These are a group of heterogeneous clinical conditions with a high degree of overlap, as well as nonspecific signs and symptoms. Several diseases involve multiple organ systems, potentially causing catastrophic dysfunction and death. In the majority of cases, endocrine challenges accompany other organ failures or manifest as a complication of prolonged intensive care unit stay and malnutrition. However, when endocrine disorders present as an isolated syndrome, they are a rare and extreme manifestation. As they are uncommon, these can typically challenge both with diagnosis and management. Acute exacerbations may be elicited by triggers such as infections, trauma, surgery, and hemorrhage. In this complex scenario, early diagnosis and prompt treatment require knowledge of the specific endocrine syndrome. Here, we review diabetic coma, hyponatremia, hypercalcemia, thyroid emergencies, pituitary insufficiency, adrenal crisis, and vitamin D deficiency, highlighting diagnostic tools and tricks, and management pathways through defining common clinical presentations.

Serum vitamin D binding protein level, but not serum total, bioavailable, free vitamin D, is higher in 30-days survivors than in nonsurvivors with sepsis

The prognostic value of 3 types (total, bioavailable, and free) of 25-hydroxy vitamin D [25(OH)D] and vitamin D binding protein (VDBP) in patients with sepsis is unknown. The aim of this study was to evaluate the association of levels of those 3 types of 25(OH) D and VDBP with 30-day mortality in patients with sepsis. From March to December 2018, patients diagnosed with sepsis and admitted to the medical intensive care unit were enrolled, prospectively. We measured total 25(OH)D and VDBP levels, performed GC genotyping for the polymorphisms rs4588 and rs7041, and calculated bioavailable and free 25(OH)D levels. Total, bioavailable, and free 25(OH)D levels did not differ in 30-days nonsurvivors and survivors. Serum VDBP level was significantly higher in survivors than nonsurvivors (138.6 ug/mL vs 108.2 ug/mL, P = .023) and was associated with 30-day mortality in univariate but not multivariate analysis. VDBP polymorphisms and allele frequencies were not statistically different between the groups. Serum VDBP level was significantly higher in survivors than nonsurvivors over 30-days mortality in septic patients. However, 3 types (total, bioavailable, and free) of 25(OH)D levels did not differ between the survivors and nonsurvivors group.

Is Lower Vitamin D Level Associated with Increased Risk of Neonatal Sepsis? A Prospective Cohort Study

OBJECTIVE

To evaluate the effect of maternal/ neonatal vitamin D levels on culture positive neonatal sepsis.

METHODS

This prospective cohort study was conducted in the NICU of a tertiary care teaching hospital in Odisha, Eastern India from January 2015 through December 2016. Forty (40) neonates with culture positive sepsis were included in the study group. Forty (40) healthy neonates admitted for evaluation of neonatal jaundice who are similar in gender, gestational age, postnatal age and without any clinical signs of sepsis were recruited as control group after informed consent. Vitamin D level (25 OH D) was assessed in the neonates and their mothers in both the groups.

RESULTS

Neonatal 25 OH vitamin D level in the study group (12.71 ± 2.82 ng/ml) was significantly lower than in the control group (25.46 ± 7.02 ng/ml). The Odds ratio was 273 (95% CI 30.39-2451.6) for culture positive sepsis in neonates with vitamin D deficiency/insufficiency. Mothers of septic neonates had significantly lower 25 OH vitamin D level (20.92 ± 3.92 ng/ml) than the mothers of healthy neonates in control group (27.31 ± 6.83 ng/ml). The Odds ratio was 4.71 (95% CI 1.69-13.1) for culture positive sepsis in babies born to mothers with vitamin D deficiency/insufficiency.

CONCLUSIONS

Neonates with vitamin D deficiency/insufficiency are at higher risk for developing sepsis than those with sufficient vitamin D levels. Lower vitamin D levels in mothers is also associated with increased risk of sepsis in the neonates.

Vitamin D-Cathelicidin Axis: at the Crossroads between Protective Immunity and Pathological Inflammation during Infection

Vitamin D signaling plays an essential role in innate defense against intracellular microorganisms via the generation of the antimicrobial protein cathelicidin. In addition to directly binding to and killing a range of pathogens, cathelicidin acts as a secondary messenger driving vitamin D-mediated inflammation during infection. Recent studies have elucidated the biological and clinical functions of cathelicidin in the context of vitamin D signaling. The vitamin D-cathelicidin axis is involved in the activation of autophagy, which enhances antimicrobial effects against diverse pathogens. Vitamin D studies have also revealed positive and negative regulatory effects of cathelicidin on inflammatory responses to pathogenic stimuli. Diverse innate and adaptive immune signals crosstalk with functional vitamin D receptor signals to enhance the role of cathelicidin action in cell-autonomous effector systems. In this review, we discuss recent findings that demonstrate how the vitamin D-cathelicidin pathway regulates autophagy machinery, protective immune defenses, and inflammation, and contributes to immune cooperation between innate and adaptive immunity. Understanding how the vitamin D-cathelicidin axis operates in the host response to infection will create opportunities for the development of new therapeutic approaches against a variety of infectious diseases.

Cathelicidin preserves intestinal barrier function in polymicrobial sepsis

Objectives

The intestinal epithelium compartmentalizes the sterile bloodstream and the commensal bacteria in the gut. Accumulating evidence suggests that this barrier is impaired in sepsis, aggravating systemic inflammation. Previous studies reported that cathelicidin is differentially expressed in various tissues in sepsis. However, its role in sepsis-induced intestinal barrier dysfunction has not been investigated.

Design

To examine the role of cathelicidin in polymicrobial sepsis, cathelicidin wild-(Cnlp^+/+) and knockout (Cnlp^−/−) mice underwent cecal-ligation and puncture (CLP) followed by the assessment of septic mortality and morbidity as well as histological, biochemical, immunological, and transcriptomic analyses in the ileal tissues. We also evaluated the prophylactic and therapeutic efficacies of vitamin D3 (an inducer of endogenous cathelicidin) in the CLP-induced murine polymicrobial sepsis model.

Results

The ileal expression of cathelicidin was increased by three-fold after CLP, peaking at 4 h. Knockout of Cnlp significantly increased 7-day mortality and was associated with a higher murine sepsis score. Alcian-blue staining revealed a reduced number of mucin-positive goblet cells, accompanied by reduced mucin expression. Increased number of apoptotic cells and cleavage of caspase-3 were observed. Cnlp deletion increased intestinal permeability to 4kD fluorescein-labeled dextran and reduced the expression of tight junction proteins claudin-1 and occludin. Notably, circulating bacterial DNA load increased more than two-fold. Transcriptome analysis revealed upregulation of cytokine/inflammatory pathway. Depletion of Cnlp induced more M1 macrophages and neutrophils compared with the wild-type mice after CLP. Mice pre-treated with cholecalciferol (an inactive form of vitamin D3) or treated with 1alpha, 25-dihydroxyvitamin D3 (an active form of VD3) had decreased 7-day mortality and significantly less severe symptoms. Intriguingly, the administration of cholecalciferol after CLP led to worsened 7-day mortality and the associated symptoms.

Conclusions

Endogenous cathelicidin promotes intestinal barrier integrity accompanied by modulating the infiltration of neutrophils and macrophages in polymicrobial sepsis. Our data suggested that 1alpha, 25-dihydroxyvitamin D3 but not cholecalciferol is a potential therapeutic agent for treating sepsis.

Immunometabolic approaches to prevent, detect, and treat neonatal sepsis

The first days of postnatal life are energetically demanding as metabolic functions change dramatically to accommodate drastic environmental and physiologic transitions after birth. It is increasingly appreciated that metabolic pathways are not only crucial for nutrition but also play important roles in regulating inflammation and the host response to infection. Neonatal susceptibility to infection is increased due to a functionally distinct immune response characterized by high reliance on innate immune mechanisms. Interactions between metabolism and the immune response are increasingly recognized, as changes in metabolic pathways drive innate immune cell function and activation and consequently host response to pathogens. Moreover, metabolites, such as acetyl-coenzyme A (acetyl-CoA) and succinate have immunoregulatory properties and serve as cofactors for enzymes involved in epigenetic reprogramming or "training" of innate immune cells after an initial infectious exposure. Highly sensitive metabolomic approaches allow us to define alterations in metabolic signatures as they change during ontogeny and as perturbed by immunization or infection, thereby linking metabolic pathways to immune cell effector functions. Characterizing the ontogeny of immunometabolism will offer new opportunities to prevent, diagnose, and treat neonatal sepsis.

25-Hydroxy Vitamin D Deficiency Is Associated With Cardiovascular Sequential Organ Failure Assessment and Pediatric Risk of Mortality III Scores in Critically Ill Children

Aim: Investigate 25-hydroxy vitamin D (25(OH)D) levels and the correlation with cardiovascular sequential organ failure assessment (CV-SOFA) and pediatric risk of mortality III (PRISM-III) scores in critically ill children. Methods: This prospective observational cohort study was conducted on consecutive critical ill children aged 1 month to 14 years old in 1 year. The blood sample was collected upon PICU admission. 25(OH)D deficiency was defined as<20 ng/mL. We performed univariate and multivariate analyses to evaluate associations with CV-SOFA and PRISM-III scores and other important outcomes. Results: 296 critically ill children were enrolled in the study. The mean serum 25(OH)D level was 22.5 (IQR 16.3-31.8) ng/mL. The prevalence of 25(OH)D deficiency was 39.2% in critically ill children. 25(OH)D levels were significantly decreased in septic shock and associated with CV-SOFA and PRISM-III scores. In multivariate analysis, vitamin D deficiency is associated with CV-SOFA and PRISM-III scores. Conclusion: 25(OH)D deficiency is prevalent in critically ill children at PICU admission and seems to be associated with higher CV-SOFA and PRISM-III scores. Our study provides additional data for 25 (OH) D statuses that impact the outcomes of critically ill children.

The Correlation between Serum Level of Vitamin D and Outcome of Sepsis Patients; a Cross-Sectional Study

INTRODUCTION

The effect of vitamin D deficiency in manifestation of sepsis and its role as an important mediator in the immune system has received attention. The present study was done with the aim of evaluating the correlation between serum levels of vitamin D and outcome of sepsis patients.

METHODS

The present cross-sectional study was performed on patients over 18 years of age suspected to sepsis presenting to an emergency department during 1 year using non-probability convenience sampling. For all eligible patients, blood sample was drawn for measurement of serum level of vitamin D3 and the correlation of this vitamin with outcomes such as mortality, renal failure, liver failure and etc. was assessed.

RESULTS

168 patients with the mean age of 70.8 ± 13.3 (43.0 - 93.0) years were studied (56.0% male). Mean serum level of vitamin D3 in the studied patients was 19.03 ± 13.08 (4.0 - 85.0) ng/ml. By considering 20 - 50 ng/ml as the normal range of vitamin D, 61.6% of the patients had vitamin D deficiency. Only age (r=-0.261, p=0.037) and mortality (r=-0.426, p=0.025) showed a significant correlation with mean vitamin D. Sepsis patients with older age and those who died had a lower level of vitamin D. Area under the ROC curve of serum vitamin D level regarding 1-month mortality of the sepsis patients was 0.701 (95%CI: 0.439 - 0.964).

CONCLUSION

Based on the results of the present study, the prevalence of vitamin D deficiency in sepsis patients presenting to the ED was estimated as 61.6%. A significant and indirect correlation was found between the serum level of vitamin D3 and mortality as well as older age. It seems that consumption of vitamin D supplements might be helpful in decreasing the prevalence of infection, sepsis, and mortality caused by it, especially in older age.

Vitamin D and critical illness: what endocrinology can learn from intensive care and vice versa

The prevalence of vitamin D deficiency in intensive care units ranges typically between 40 and 70%. There are many reasons for being or becoming deficient in the ICU. Hepatic, parathyroid and renal dysfunction additionally increases the risk for developing vitamin D deficiency. Moreover, therapeutic interventions like fluid resuscitation, dialysis, surgery, extracorporeal membrane oxygenation, cardiopulmonary bypass and plasma exchange may significantly reduce vitamin D levels. Many observational studies have consistently shown an association between low vitamin D levels and poor clinical outcomes in critically ill adults and children, including excess mortality and morbidity such as acute kidney injury, acute respiratory failure, duration of mechanical ventilation and sepsis. It is biologically plausible that vitamin D deficiency is an important and modifiable contributor to poor prognosis during and after critical illness. Although vitamin D supplementation is inexpensive, simple and has an excellent safety profile, testing for and treating vitamin D deficiency is currently not routinely performed. Overall, less than 800 patients have been included in RCTs worldwide, but the available data suggest that high-dose vitamin D supplementation could be beneficial. Two large RCTs in Europe and the United States, together aiming to recruit >5000 patients, have started in 2017, and will greatly improve our knowledge in this field. This review aims to summarize current knowledge in this interdisciplinary topic and give an outlook on its highly dynamic future.

Vitamin D to Prevent Lung Injury Following Esophagectomy-A Randomized, Placebo-Controlled Trial

OBJECTIVES

Observational studies suggest an association between vitamin D deficiency and adverse outcomes of critical illness and identify it as a potential risk factor for the development of lung injury. To determine whether preoperative administration of oral high-dose cholecalciferol ameliorates early acute lung injury postoperatively in adults undergoing elective esophagectomy.

DESIGN

A double-blind, randomized, placebo-controlled trial.

SETTING

Three large U.K. university hospitals.

PATIENTS

Seventy-nine adult patients undergoing elective esophagectomy were randomized.

INTERVENTIONS

A single oral preoperative (3-14 d) dose of 7.5 mg (300,000 IU; 15 mL) cholecalciferol or matched placebo.

MEASUREMENTS AND MAIN RESULTS

Primary outcome was change in extravascular lung water index at the end of esophagectomy. Secondary outcomes included PaO2:FIO2 ratio, development of lung injury, ventilator and organ-failure free days, 28 and 90 day survival, safety of cholecalciferol supplementation, plasma vitamin D status (25(OH)D, 1,25(OH)2D, and vitamin D-binding protein), pulmonary vascular permeability index, and extravascular lung water index day 1 postoperatively. An exploratory study measured biomarkers of alveolar-capillary inflammation and injury. Forty patients were randomized to cholecalciferol and 39 to placebo. There was no significant change in extravascular lung water index at the end of the operation between treatment groups (placebo median 1.0 [interquartile range, 0.4-1.8] vs cholecalciferol median 0.4 mL/kg [interquartile range, 0.4-1.2 mL/kg]; p = 0.059). Median pulmonary vascular permeability index values were significantly lower in the cholecalciferol treatment group (placebo 0.4 [interquartile range, 0-0.7] vs cholecalciferol 0.1 [interquartile range, -0.15 to -0.35]; p = 0.027). Cholecalciferol treatment effectively increased 25(OH)D concentrations, but surgery resulted in a decrease in 25(OH)D concentrations at day 3 in both arms. There was no difference in clinical outcomes.

CONCLUSIONS

High-dose preoperative treatment with oral cholecalciferol was effective at increasing 25(OH)D concentrations and reduced changes in postoperative pulmonary vascular permeability index, but not extravascular lung water index.

Risks of the 'Sunshine pill' - a case of hypervitaminosis D

Vitamin D is a fat-soluble vitamin essential for calcium homeostasis and bone health. Vitamin D toxicity or hypervitaminosis D is extremely rare. We describe the case of a 73-year-old man who presented with life-threatening hypervitaminosis D and hypercalcaemia resulting from self-medicated doses of vitamin D supplements. This case, alongside other global case reports, highlights the potential dangers of unlicensed vitamin D replacement. We discuss the evidence for vitamin D replacement and remind readers of the current guidance on daily intake and supplementation.

Vitamin D deficiency and clinical outcomes related to septic shock in children with critical illness: a systematic review

PURPOSE

Low vitamin D blood levels are related to many clinical outcomes in children with critically illness. However, the relationship of it and septic shock has not been systematically analyzed. The objective of this review was to evaluate the effect of vitamin D on septic shock and predict if vitamin D administration can improve prognosis of it.

MATERIALS AND METHODS

Online databases were searched up to June 1st, 2017 for studies on the relation of vitamin D deficiency (VDD) and clinical outcomes on septic shock in children with critical illness. The primary end point was the effect of VDD on occurrence of septic shock. The secondary endpoints were the association of VDD and clinical outcomes related to septic shock. We summarized the strength of association between VDD and each factor on septic shock. Individual factors were defined as strong, moderate, weak, or inconclusive according to the numbers of the article supporting the relation between them.

RESULTS

Eight studies published between 2012 and 2017, for a total of 1367 patients, were included in the final analysis. We extracted eight patient-level factors and among them one showed strong association of VDD and septic shock. Four factors demonstrated moderate or weak strength of evidence for it: nonresolution of shock, catecholamine refractory shock, fluid boluses, vasopressor use. But evidence for the association between VDD and severity of illness, stay of pediatric intensive care unit (PICU), are weak. Most of the articles showed no significant association between VDD and mortality.

CONCLUSIONS

Among critically ill children, VDD might be associated with the occurrence and resolution of septic shock. A larger multicenter trial could conclusively confirm these findings. Further research is also needed to identify vitamin D administration for better outcomes in pediatric patients.

A review of micronutrients in sepsis: the role of thiamine, l-carnitine, vitamin C, selenium and vitamin D

Sepsis is defined as the dysregulated host response to an infection resulting in life-threatening organ dysfunction. The metabolic demand from inefficiencies in anaerobic metabolism, mitochondrial and cellular dysfunction, increased cellular turnover, and free-radical damage result in the increased focus of micronutrients in sepsis as they play a pivotal role in these processes. In the present review, we will evaluate the potential role of micronutrients in sepsis, specifically, thiamine, l-carnitine, vitamin C, Se and vitamin D. Each micronutrient will be reviewed in a similar fashion, discussing its major role in normal physiology, suspected role in sepsis, use as a biomarker, discussion of the major basic science and human studies, and conclusion statement. Based on the current available data, we conclude that thiamine may be considered in all septic patients at risk for thiamine deficiency and l-carnitine and vitamin C to those in septic shock. Clinical trials are currently underway which may provide greater insight into the role of micronutrients in sepsis and validate standard utilisation.

T cells and their immunometabolism: A novel way to understanding sepsis immunopathogenesis and future therapeutics

Sepsis has always been considered as a big challenge for pharmaceutical companies in terms of discovering and designing new therapeutics. The pathogenesis of sepsis involves aberrant activation of innate immune cells (i.e. macrophages, neutrophils etc.) at early stages. However, a stage of immunosuppression is also observed during sepsis even in the patients who have recovered from it. This stage of immunosuppression is observed due to the loss of conventional (i.e. CD4⁺, CD8⁺) T cells, Th17 cells and an upregulation of regulatory T cells (Tregs). This process also impacts metabolic processes controlling immune cell metabolism called immunometabolism. The present review is focused on the T cell-mediated immune response, their immunometabolism and targeting T cell immunometabolism during sepsis as future therapeutic approach. The first part of the manuscripts describes an impact of sepsis on conventional T cells, Th17 cells and Tregs along with their impact on sepsis. The subsequent section further describes the immunometabolism of these cells (CD4⁺, CD8⁺, Th17, and Tregs) under normal conditions and during sepsis-induced immunosuppression. The article ends with the therapeutic targeting of T cell immunometabolism (both conventional T cells and Tregs) during sepsis as a future immunomodulatory approach for its management.

The podoplanin-CLEC-2 axis inhibits inflammation in sepsis

Platelets play a critical role in vascular inflammation through the podoplanin and collagen/fibrin receptors, C-type-lectin-like-2 (CLEC-2) and glycoprotein VI (GPVI), respectively. Both receptors regulate endothelial permeability and prevent peri-vascular bleeding in inflammation. Here we show that platelet-specific deletion of CLEC-2 but not GPVI leads to enhanced systemic inflammation and accelerated organ injury in two mouse models of sepsis-intra-peritoneal lipopolysaccharide and cecal ligation and puncture. CLEC-2 deficiency is associated with reduced numbers of podoplanin-expressing macrophages despite increased cytokine and chemokine levels in the infected peritoneum. Pharmacological inhibition of the interaction between CLEC-2 and podoplanin regulates immune cell infiltration and the inflammatory reaction during sepsis, suggesting that activation of podoplanin underlies the anti-inflammatory action of platelet CLEC-2. We suggest podoplanin-CLEC-2 as a novel anti-inflammatory axis regulating immune cell recruitment and activation in sepsis.

Vitamin D kinetics in the acute phase of critical illness: A prospective observational study

PURPOSE

The objective of this study was to assess the vitamin D kinetics in critically ill patients by performing periodic serum vitamin D measurements in short time intervals in the initial phase of a critical illness.

MATERIALS AND METHODS

We performed vitamin D serum measurements: at admission and then in 12-hour time intervals. The minimum number of vitamin D measurements was 4, and the maximum was 8 per patient.

RESULTS

A total of 363 patients were evaluated for participation, and 20 met the inclusion criteria. All patients had an initial serum vitamin D level between 10.6 and 39ng/mL. Nineteen patients had vitamin D levels between 10 and 30ng/mL, which means that they had vitamin D insufficiency or deficiency, and only one patient had a normal vitamin D serum plasma level. We observed that the median of the vitamin D level decreases until the fourth measurement then stabilizes around the 4th and 5th measurement and then appears to increase unevenly. The highest drop is at the very beginning.

CONCLUSIONS

The vitamin D serum level is changeable in the initial phase of a critical illness. We hypothesize that the serum vitamin D concentration can mirror the severity of illness.

Anti-Inflammatory Effects of Vitamin D on Human Immune Cells in the Context of Bacterial Infection

Vitamin D induces a diverse range of biological effects, including important functions in bone health, calcium homeostasis and, more recently, on immune function. The role of vitamin D during infection is of particular interest given data from epidemiological studies suggesting that vitamin D deficiency is associated with an increased risk of infection. Vitamin D has diverse immunomodulatory functions, although its role during bacterial infection remains unclear. In this study, we examined the effects of 1,25(OH)₂D₃, the active metabolite of vitamin D, on peripheral blood mononuclear cells (PBMCs) and purified immune cell subsets isolated from healthy adults following stimulation with the bacterial ligands heat-killed pneumococcal serotype 19F (HK19F) and lipopolysaccharide (LPS). We found that 1,25(OH)₂D₃ significantly reduced pro-inflammatory cytokines TNF-α, IFN-γ, and IL-1β as well as the chemokine IL-8 for both ligands (three- to 53-fold), while anti-inflammatory IL-10 was increased (two-fold, p = 0.016) in HK19F-stimulated monocytes. Levels of HK19F-specific IFN-γ were significantly higher (11.7-fold, p = 0.038) in vitamin D-insufficient adults (<50 nmol/L) compared to sufficient adults (>50 nmol/L). Vitamin D also shifted the pro-inflammatory/anti-inflammatory balance towards an anti-inflammatory phenotype and increased the CD14 expression on monocytes (p = 0.008) in response to LPS but not HK19F stimulation. These results suggest that 1,25(OH)₂D₃ may be an important regulator of the inflammatory response and supports further in vivo and clinical studies to confirm the potential benefits of vitamin D in this context.