Effect of 1,25-dihydroxy-vitamin D3 in experimental sepsis

Unveiling the Novel Benefits of Co-Administering Butyrate and Active Vitamin D3 in Mice Subjected to Chemotherapy-Induced Gut-Derived Pseudomonas aeruginosa Sepsis

Cancer patients face increased susceptibility to invasive infections, primarily due to ulcerative lesions on mucosal surfaces and immune suppression resulting from chemotherapy. Pseudomonas aeruginosa (P. aeruginosa) bacteremia is notorious for its rapid progression into fatal sepsis, posing a significant threat to cancer patients, particularly those experiencing chemotherapy-induced neutropenia. This bacterial infection contributes significantly to morbidity and mortality rates among such individuals. Our latest report showed the mutually beneficial effects of postbiotic butyrate on 1,25-dihydroxyvitamin D3 (1,25D3)-controlled innate immunity during Salmonella colitis. Hence, we investigated the impact of butyrate and 1,25D3 on chemotherapy-induced gut-derived P. aeruginosa sepsis in mice. The chemotherapy-induced gut-derived P. aeruginosa sepsis model was established through oral administration of 1 × 107 CFU of the P. aeruginosa wild-type strain PAO1 in C57BL/6 mice undergoing chemotherapy. Throughout the infection process, mice were orally administered butyrate and/or 1,25D3. Our observations revealed that the combined action of butyrate and 1,25D3 led to a reduction in the severity of colitis and the invasion of P. aeruginosa into the liver and spleen of the mice. This reduction was attributed to an enhancement in the expression of defensive cytokines and antimicrobial peptides within the cecum, coupled with decreased levels of zonulin and claudin-2 proteins in the mucosal lining. These effects were notably more pronounced when compared to treatments administered individually. This study unveils a promising alternative therapy that involves combining postbiotics and 1,25D3 for treating chemotherapy-induced gut-derived P. aeruginosa sepsis.

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.

Vitamin D receptor (VDR) on the cell membrane of mouse macrophages participates in the formation of lipopolysaccharide tolerance: mVDR is related to the effect of artesunate to reverse LPS tolerance

It is unclear whether membrane vitamin D receptor (mVDR) exists on the macrophage membrane or whether mVDR is associated with lipopolysaccharide (LPS) tolerance. Herein, we report that interfering with caveolae and caveolae-dependent lipid rafts inhibited the formation of LPS tolerance. VDR was detected as co-localized with membrane molecular markers. VDR was detected on the cell membrane and its level was higher in LPS-tolerant cells than that in only LPS treatment cells. Anti-VDR antibodies could abolish the effect of artesunate (AS) to reverse LPS tolerance, and the wild-type peptides (H397 and H305) of VDR, but not the mutant peptide (H397D and H305A), led to the loss of AS's effect. AS decreased the mVDR level in LPS-tolerant cells. In vivo, AS significantly reduced VDR level in the lung tissue of LPS-tolerant mice. In summary, mVDR exists on the cell membrane of macrophages and is closely associated with the formation of LPS tolerance and the effects of AS. Video Abstract.

The Role of Vitamin D in SARS-CoV-2 Infection and Acute Kidney Injury

Vitamin D has been described as an essential nutrient and hormone, which can cause nuclear, non-genomic, and mitochondrial effects. Vitamin D not only controls the transcription of thousands of genes, directly or indirectly through the modulation of calcium fluxes, but it also influences the cell metabolism and maintenance specific nuclear programs. Given its broad spectrum of activity and multiple molecular targets, a deficiency of vitamin D can be involved in many pathologies. Vitamin D deficiency also influences mortality and multiple outcomes in chronic kidney disease (CKD). Active and native vitamin D serum levels are also decreased in critically ill patients and are associated with acute kidney injury (AKI) and in-hospital mortality. In addition to regulating calcium and phosphate homeostasis, vitamin D-related mechanisms regulate adaptive and innate immunity. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections have a role in excessive proinflammatory cell recruitment and cytokine release, which contribute to alveolar and full-body endothelial damage. AKI is one of the most common extrapulmonary manifestations of severe coronavirus disease 2019 (COVID-19). There are also some correlations between the vitamin D level and COVID-19 severity via several pathways. Proper vitamin D supplementation may be an attractive therapeutic strategy for AKI and has the benefits of low cost and low risk of toxicity and side effects.

Vitamin therapy in sepsis

Vitamins are essential micronutrients with key roles in many biological pathways relevant to sepsis. Some of these relevant biological mechanisms include antioxidant and anti-inflammatory effects, protein and hormone synthesis, energy generation, and regulation of gene transcription. Moreover, relative vitamin deficiencies in plasma are common during sepsis and vitamin therapy has been associated with improved outcomes in some adult and pediatric studies. High-dose intravenous vitamin C has been the vitamin therapy most extensively studied in adult patients with sepsis and septic shock. This includes three randomized control trials (RCTs) as monotherapy with a total of 219 patients showing significant reduction in organ dysfunction and lower mortality when compared to placebo, and five RCTs as a combination therapy with thiamine and hydrocortisone with a total of 1134 patients showing no difference in clinical outcomes. Likewise, the evidence for the role of other vitamins in sepsis remains mixed. In this narrative review, we present the preclinical, clinical, and safety evidence of the most studied vitamins in sepsis, including vitamin C, thiamine (i.e., vitamin B₁), and vitamin D. We also present the relevant evidence of the other vitamins that have been studied in sepsis and critical illness in both children and adults, including vitamins A, B₂, B₆, B₁₂, and E. IMPACT: Vitamins are key effectors in many biological processes relevant to sepsis. We present the preclinical, clinical, and safety evidence of the most studied vitamins in pediatric sepsis. Designing response-adaptive platform trials may help fill in knowledge gaps regarding vitamin use for critical illness and association with clinical outcomes.

Biologically active 1,25-dihydroxyvitamin D3 protects against experimental sepsis by negatively regulating the Toll-like receptor 4/myeloid differentiation primary response gene 88/Toll-IL-1 resistance-domain-containing adapter-inducing interferon-β signaling pathway

The hormonally active form of vitamin D (VD), 1,25‑dihydroxyvitamin D3, has been reported to be a key immunoregulator in the reduction of inflammation. In this study, we investigated the effects of VD in an experimental sepsis cell model, and the underlying mechanisms. The sepsis cell model was first established in monocytes, isolated from newborns and healthy adults, which were stimulation with lipopolysaccharide (LPS). We observed that cell viability was significantly impaired in the monocytes after LPS stimulation, using a Cell Counting Kit‑8 and trypan blue assays. Additionally, ELISA revealed that LPS stimulation significantly elevated the expression of interleukin 6 (IL‑6), IL‑10 and tumor necrosis factor‑α (TNF‑α). The expression levels of Toll‑like receptor (TLR4), myeloid differentiation primary response gene 88 (MyD88), and Toll‑IL‑1 resistance‑domain‑containing adapter‑inducing interferon‑β (TRIF) mRNA were also significantly elevated under LPS stimulation using reverse transcription‑quantitative PCR and western blot analysis. VD treatment could significantly suppress the effects of LPS simulation on monocytes by negatively regulating inflammatory cytokines and TLR4/MyD88/TRIF signaling. Furthermore, a regulatory feedback mechanism was proposed to involve TLR4, MyD88 and TRIF in the sepsis cell model. In conclusion, VD may effectively decrease the release of inflammatory cytokines by inhibiting the TLR4/MyD88/TRIF signaling pathway, could be considered as a potential therapeutic agent for the treatment of sepsis.

Effect of Severe Vitamin D Deficiency at Admission on Shock Reversal in Children With Septic Shock: A Prospective Observational Study

OBJECTIVES:

To evaluate the association of severe vitamin D deficiency with clinically important outcomes in children with septic shock.

METHODS:

We enrolled children ≤17 years with septic shock prospectively over a period of 6 months. We estimated 25-hydroxyvitamin D [25 (OH) D] levels at admission and 72 hours. Severe deficiency was defined as serum 25 (OH) <10 ng/mL. We performed univariate and multivariate analysis to evaluate association with clinically important outcomes.

RESULTS:

Forty-three children were enrolled in the study. The prevalence of severe vitamin D deficiency was 72% and 69% at admission and 72 hours, respectively. On univariate analysis, severe vitamin D deficiency at admission was associated with lower rates of shock reversal, 74% (23) versus 25% (3); relative risk (95% confidence interval [CI]): 2.9 (1.09-8.08), at 24 hours and greater need for fluid boluses (75 vs 59 mL/kg). On multivariate analysis, nonresolution of shock at 24 hours was significantly associated with severe vitamin D deficiency after adjusting for other key baseline and clinical variables, adjusted odds ratio (95% CI): 12 (2.01-87.01); 0.01.

CONCLUSION:

The prevalence of severe vitamin D deficiency is high in children with septic shock admitted to pediatric intensive care unit. Severe vitamin D deficiency at admission seems to be associated with lower rates of shock reversal at 24 hours of ICU stay. Our study provides preliminary data for planning interventional studies in children with septic shock and severe vitamin D deficiency.

Mediators in Preterm Infants With Late-onset Sepsis: A Randomized Controlled Trial

OBJECTIVE

To evaluate biochemical and clinical effects of 2 different doses of vitamin D supplementation in preterm infants with late-onset sepsis (LOS).

STUDY DESIGN

A double blinded randomized controlled stratified trial included preterm infants with gestational age (GA) ≥28 weeks with LOS. Subjects were randomly assigned to receive 400 or 800 IU/day of vitamin D3. Serum concentrations of 25(OH)D, TNF-α, and IL-6 were measured at enrollment, 7 days after vitamin D supplementation, and at 40 weeks of postmenstrual age (PMA). Short-term outcomes and growth parameters were assessed.

RESULTS

A total of 50 infants were enrolled, 25 in each group. Seventy-six percentage of enrolled infants were vitamin D-deficient at enrollment in both groups whereas only one infant in the 400 IU and none in the 800 IU group remained deficient at 40 week's PMA; vitamin D concentrations at 40 weeks PMA were 54.8 ± 35.1 and 67.4 ± 37.1 ng/mL, respectively, P = 0.01). None of the infants enrolled in the study had signs of vitamin D toxicity. Serum pro-inflammatory cytokines IL-6 and TNF- α concentrations decreased at 1 week and at discharge in both groups without differences between groups. The 2 groups did not differ in anthropometric measurements, duration of oxygen and respiratory support, duration of antimicrobial use, length of hospital stay, and mortality.

CONCLUSIONS

A dose of 400 IU of vitamin D was adequate to treat vitamin D deficiency in the majority of premature infants with LOS. The 2 dosing regimens did not differ in clinical or biochemical changes.

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.

Association of vitamin D receptor gene FokI polymorphism and susceptibility to CAP in Egyptian children: a multicenter study

BACKGROUND

Community-acquired pneumonia (CAP) is the leading cause of child deaths around the world. Recently, the vitamin D receptor (VDR) gene has emerged as a susceptibility gene for CAP.

OBJECTIVES

To evaluate the association of the VDR gene Fok I polymorphism with susceptibility to CAP in Egyptian children.

METHODS

This was a multicenter case-control study of 300 patients diagnosed with CAP, and 300 well-matched healthy control children. The VDR Fok I (rs2228570) polymorphism was genotyped by PCR-restriction fragment length polymorphism (RFLP), meanwhile serum 25-hydroxy vitamin D (25D) level was assessed using ELISA method.

RESULTS

The frequencies of the VDR FF genotype and F allele were more common in patients with CAP than in our control group (OR = 3.6; (95% CI: 1.9-6.7) for the FF genotype; P = 0.001) and (OR: 1.8; (95% CI: 1.4-2.3) for the F allele; P = 0.01). Patients carrying the VDR FF genotype had lower serum (25D) level (mean; 14.8 ± 3.6 ng/ml) than Ff genotype (20.6 ± 4.5 ng/ml) and the ff genotype (24.5 ± 3.7 ng/ml); P < 0.01.

CONCLUSION

The VDR gene Fok I (rs2228570) polymorphism confers susceptibility to CAP in Egyptian children.

Calcium Ion Channels: Roles in Infection and Sepsis Mechanisms of Calcium Channel Blocker Benefits in Immunocompromised Patients at Risk for Infection

Immunosuppression may occur for a number of reasons related to an individual's frailty, debility, disease or from therapeutic iatrogenic intervention or misadventure. A large percentage of morbidity and mortality in immunodeficient populations is related to an inadequate response to infectious agents with slow response to antibiotics, enhancements of antibiotic resistance in populations, and markedly increased prevalence of acute inflammatory response, septic and infection related death. Given known relationships between intracellular calcium ion concentrations and cytotoxicity and cellular death, we looked at currently available data linking blockade of calcium ion channels and potential decrease in expression of sepsis among immunosuppressed patients. Notable are relationships between calcium, calcium channel, vitamin D mechanisms associated with sepsis and demonstration of antibiotic-resistant pathogens that may utilize channels sensitive to calcium channel blocker. We note that sepsis shock syndrome represents loss of regulation of inflammatory response to infection and that vitamin D, parathyroid hormone, fibroblast growth factor, and klotho interact with sepsis defense mechanisms in which movement of calcium and phosphorus are part of the process. Given these observations we consider that further investigation of the effect of relatively inexpensive calcium channel blockade agents of infections in immunosuppressed populations might be worthwhile.

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.

Cardiac tissue oxidative stress and inflammation after vitamin D administrations in high fat- diet induced obese rats

BACKGROUND

Obesity is associated with numerous metabolic and inflammatory disorders. The current study was aimed to evaluate the effects of vitamin D administration on the markers of oxidative stress and inflammation in the cardiac tissue of high-fat diet induced obese rats.

METHODS

In the beginning of the study, 40 male Wistar rats were divided into two groups: normal diet (ND) and high fat diet (HFD) for 16 weeks; then each group subdivided into two groups including: ND, ND + vitamin D, HFD and HFD + vitamin D. Vitamin D supplementation was done for 5 weeks at 500 IU/kg dosage. Tumor necrosis factor (TNF)-α concentration and markers of oxidative stress including glutathione peroxidase (GPx), superoxide dismutase (SOD), malondialdehyde (MDA) and catalase (CAT) concentrations in the cardiac tissue and serum concentrations of lipids in rats were determined using ELISA kits and spectrophotometry methods respectively.

RESULTS

According to our results, GPx activity in ND and ND + vitamin D group was significantly higher compared with HFD group. Similarly, SOD activity was also significantly increased in ND + vitamin D group compared with ND and HFD groups. Moreover, vitamin D administration, significantly reduced catalase activity in ND + vitamin D and HFD + vitamin D groups (P < 0.05). TNF-α concentration in heart tissue in ND + vitamin D group significantly reduced compared with ND group. Cardiac tissue MDA concentration in baseline or after vitamin D administration did not changed significantly.

CONCLUSION

Vitamin D improved cardiac oxidative stress and inflammatory markers in HFD induced obese rats. Further studies in human models are needed to further confirm the use of this nutrient in daily clinical practice.

Vitamin D Deficiency in Human and Murine Sepsis

Supplemental Digital Content is available in the text.

Objectives:

Vitamin D deficiency has been implicated as a pathogenic factor in sepsis and ICU mortality but causality of these associations has not been demonstrated. To determine whether sepsis and severe sepsis are associated with vitamin D deficiency and to determine whether vitamin D deficiency influences the severity of sepsis.

Design, Setting, and Patients:

Sixty-one patients with sepsis and severe sepsis from two large U.K. hospitals and 20 healthy controls were recruited. Murine models of cecal ligation and puncture and intratracheal lipopolysaccharide were undertaken in normal and vitamin D deficient mice to address the issue of causality.

Measurements and Main Results:

Patients with severe sepsis had significantly lower concentrations of 25-hydroxyvitamin D₃ than patients with either mild sepsis or age-matched healthy controls (15.7 vs 49.5 vs 66.5 nmol/L; p = 0.0001). 25-hydroxyvitamin D₃ concentrations were significantly lower in patients who had positive microbiologic culture than those who were culture negative (p = 0.0023) as well as those who died within 30 days of hospital admission (p = 0.025). Vitamin D deficiency in murine sepsis was associated with increased peritoneal (p = 0.037), systemic (p = 0.019), and bronchoalveolar lavage (p = 0.011) quantitative bacterial culture. This was associated with reduced local expression of the cathelicidin-related antimicrobial peptide as well as evidence of defective macrophage phagocytosis (p = 0.029). In the intratracheal lipopolysaccharide model, 1,500 IU of intraperitoneal cholecalciferol treatment 6 hours postinjury reduced alveolar inflammation, cellular damage, and hypoxia.

Conclusions:

Vitamin D deficiency is common in severe sepsis. This appears to contribute to the development of the condition in clinically relevant murine models and approaches to correct vitamin D deficiency in patients with sepsis should be developed.

The vitamin D analogue paricalcitol attenuates hepatic ischemia/reperfusion injury through down-regulation of Toll-like receptor 4 signaling in rats

INTRODUCTION

Recent studies have revealed that vitamin D and its synthetic analogues have a protective effect on experimental ischemia/reperfusion (I/R) models in several organs, but little is known about its effect on the liver. The aim of this study was to evaluate the beneficial effects of vitamin D in a model of liver I/R in rats, focusing on Toll-like receptor (TLR) 4 signaling, which has been shown to be involved in I/R injury.

MATERIAL AND METHODS

Twenty-four male Wistar rats were randomized into four groups: Saline + Sham, Saline + I/R, Paricalcitol + Sham, and Paricalcitol + I/R. A synthetic vitamin D₂ analogue, paricalcitol, was intraperitoneally injected 24 h prior to surgery. The animals were subjected to 60 min of partial warm ischemia (70%), followed by reperfusion for 6 h on the same day. The ischemic lobe of the liver and blood were collected for molecular biochemical analyses.

RESULTS

Liver damage following I/R was diminished by pretreatment with paricalcitol. Pretreatment with paricalcitol decreased the levels of pro-inflammatory mediators, such as interleukin (IL)-1β, tumor necrosis factor (TNF)-α, and macrophage migration inhibitory factor (MIF), in both plasma and liver tissue. In addition, pretreatment with paricalcitol markedly down-regulated the expression of TLR4, HMGB1, TNF-α and NF-κB.

CONCLUSIONS

The vitamin D analogue paricalcitol attenuates hepatic I/R injury through down-regulation of the TLR4 signaling pathway and might be considered to be a potential nutritional therapeutic agent against I/R injury in the liver.

Does calcium channel blockade have a role in prevention of expression of sepsis in renal transplant recipients?

Many antihypertensive agents have been demonstrated to assist in preservation of kidney function, among them those that modulate calcium channels. Calcium channel blockers may also be of value in protecting hemodialysis patients from complications of sepsis. In diabetic recipients of kidney transplant allografts treated with cyclosporine, calcium channel blockade has been retrospectively linked to improved graft preservation and to fewer episodes of sepsis. This brief review outlines clinical and experimental publications on potential protection from sepsis by addition of calcium channel blockers to standard antibiotic therapy in individuals who may or may not have normal kidney function, or in the presence or absence of immunosuppression. Such mechanisms include blockade of antibiotic cytosolic extrusion in the cases of Pneumococci, Mycobacterium tuberculosis, Plasmodium falciparum malaria, or Schistosoma mansoni; blockade of the calcineurin/calmodulin pathway (in immunosuppressed patients allowing for lower dosage of cyclosporine); stabilization of calcium movement at the level of sarcoplasmic reticulum by which shock (vasopressor instability) is prevented; or of cytosolic calcium influx and cell death (in the case of allograft acute tubular necrosis). Given the high cost of development of new antibiotics, a role for generic calcium channel blockade in sepsis prevention should be pursued by additional studies to investigate potential links between blockade of calcium channels and expression of sepsis in at-risk populations.

Addition of 25-hydroxyvitamin D levels to the Deyo-Charlson Comorbidity Index improves 90-day mortality prediction in critically ill patients

Background

The Deyo-Charlson Comorbidity Index (DCCI) has low predictive value in the intensive care unit (ICU). Our goal was to determine whether addition of 25-hydroxyvitamin D (25OHD) levels to the DCCI improved 90-day mortality prediction in critically ill patients.

Methods

Plasma 25OHD levels, DCCI, and Acute Physiology and Chronic Health Evaluation II (APACHE II) scores were assessed within 24 h of admission in 310 ICU patients. Receiver operating characteristic curves of the prediction scores, without and with the addition of 25OHD levels, for 90-day mortality were constructed and the areas under the curve (AUC) were compared for equality.

Results

Mean (standard deviation) plasma 25OHD levels, DCCI, and APACHE II score were 19 (SD 8) ng/mL, 4 (SD 3), and 17 (SD 9), respectively. Overall 90-day mortality was 19 %. AUC for DCCI vs. DCCI + 25OHD was 0.68 (95 % CI 0.58–0.77) vs. 0.75 (95 % CI 0.67–0.83); p < 0.001. AUC for APACHE II vs. APACHE II + 25OHD was 0.81 (95 % CI 0.73–0.88) vs. 0.82 (95 % CI 0.75–0.89); p < 0.001. There was a significant difference between the AUC for DCCI + 25OHD and APACHE II + 25OHD (p = 0.04) but not between the AUC for DCCI + 25OHD and APACHE II (p = 0.12).

Conclusions

In our cohort of ICU patients, the addition of 25OHD levels to the DCCI improved 90-day mortality prediction compared to the DCCI alone. Moreover, the predictive capability of DCCI + 25OHD was comparable to that of APACHE II. Future prospective studies are needed to validate our findings and to determine whether the use of DCCI + 25OHD can influence clinical decision-making.

Metabolomics-Based Discovery of Small Molecule Biomarkers in Serum Associated with Dengue Virus Infections and Disease Outcomes

BACKGROUND

Epidemic dengue fever (DF) and dengue hemorrhagic fever/dengue shock syndrome (DHF/DSS) are overwhelming public health capacity for diagnosis and clinical care of dengue patients throughout the tropical and subtropical world. The ability to predict severe dengue disease outcomes (DHF/DSS) using acute phase clinical specimens would be of enormous value to physicians and health care workers for appropriate triaging of patients for clinical management. Advances in the field of metabolomics and analytic software provide new opportunities to identify host small molecule biomarkers (SMBs) in acute phase clinical specimens that differentiate dengue disease outcomes.

METHODOLOGY/PRINCIPAL FINDINGS

Exploratory metabolomic studies were conducted to characterize the serum metabolome of patients who experienced different dengue disease outcomes. Serum samples from dengue patients from Nicaragua and Mexico were retrospectively obtained, and hydrophilic interaction liquid chromatography (HILIC)-mass spectrometry (MS) identified small molecule metabolites that were associated with and statistically differentiated DHF/DSS, DF, and non-dengue (ND) diagnosis groups. In the Nicaraguan samples, 191 metabolites differentiated DF from ND outcomes and 83 differentiated DHF/DSS and DF outcomes. In the Mexican samples, 306 metabolites differentiated DF from ND and 37 differentiated DHF/DSS and DF outcomes. The structural identities of 13 metabolites were confirmed using tandem mass spectrometry (MS/MS). Metabolomic analysis of serum samples from patients diagnosed as DF who progressed to DHF/DSS identified 65 metabolites that predicted dengue disease outcomes. Differential perturbation of the serum metabolome was demonstrated following infection with different DENV serotypes and following primary and secondary DENV infections.

CONCLUSIONS/SIGNIFICANCE

These results provide proof-of-concept that a metabolomics approach can be used to identify metabolites or SMBs in serum specimens that are associated with distinct DENV infections and disease outcomes. The differentiating metabolites also provide insights into metabolic pathways and pathogenic and immunologic mechanisms associated with dengue disease severity.

Vitamin D deficiency decreases survival of bacterial meningoencephalitis in mice

Background

Meningoencephalitis caused by Escherichia coli is associated with high rates of mortality and risk of neurological sequelae in newborns and infants and in older or immunocompromised adults. A high prevalence of neurological disorders has been observed in geriatric populations at risk of hypovitaminosis D.

Methods

In vivo, we studied the effects of vitamin D3 on survival and the host’s immune response in experimental bacterial meningoencephalitis in mice after intracerebral E. coli infection. To produce different systemic vitamin D3 concentrations, mice received a low, standard, or high dietary vitamin D3 supplementation. Bacterial titers in blood, spleen, and brain homogenates were determined. Leukocyte infiltration was assessed by histological scores, and tissue cytokine or chemokine concentrations were measured.

Results

Mice fed a diet with low vitamin D3 concentration died earlier than control animals after intracerebral infection. Vitamin D deficiency did not inhibit leukocyte recruitment into the subarachnoid space and did not lead to an increased density of bacteria in blood, spleen, or brain homogenates. The release of proinflammatory interleukin (IL)-6 was decreased and the release of anti-inflammatory IL-10 was increased in mice fed a diet with high vitamin D3 supplementation.

Conclusion

Our observations suggest a detrimental role of vitamin D deficiency in bacterial central nervous system infections. Vitamin D may exert immune regulatory functions.

Lower vitamin D levels are associated with increased risk of early-onset neonatal sepsis in term infants

OBJECTIVE

To evaluate the effect of vitamin D levels on early-onset sepsis (EOS) in term infants.

STUDY DESIGN

Fifty term infants with clinical and laboratory findings of EOS (study group) and 50 healthy infants with no signs of clinical/laboratory infection (control group) were enrolled. Blood was drawn at the time of admission during the first 3 postnatal days of life in both groups for measurement of 25-hydroxyvitamin D (25-OHD) levels.

RESULT

Maternal and neonatal 25-OHD levels (22.2/8.6 ng ml(-1), respectively) in the study group were significantly lower than those of the control group (36.2/19 ng ml(-1), respectively, P<0.001). A positive correlation was detected between maternal and neonatal 25-OHD levels. Severe vitamin D deficiency was significantly more common in the sepsis group.

CONCLUSION

Lower maternal and neonatal 25-OHD levels are associated with EOS. These data suggest that adequate vitamin D supplementation during pregnancy may be helpful to prevent EOS in term neonates.

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.

Vitamin D deficiency in community-acquired pneumonia: low levels of 1,25(OH)2 D are associated with disease severity

OBJECTIVES

We aimed to explore the association between vitamin D levels and the severity, mortality and microbiological etiology of community-acquired pneumonia.

METHODS

Vitamin D levels (both, the reservoir form 25-OH and the activated form 1,25-OH2) of 300 randomly selected patients with community-acquired pneumonia due to pre-specified pathogens included in the German competence network (CAPNETZ) study were measured. Prior to statistical analysis, values of 25-OH and 1,25-OH2 were power-transformed to achieve parametric distribution. All further analyses were performed with seasonally and age adjusted values.

RESULTS

There was only a modest (Spearman Coefficient 0.38) positive correlation between 25-OH and 1,25-OH2. For 1,25-OH2 but not 25-OH, the general linear model revealed a significant inverse correlation between serum concentration and CURB score (p = 0.011). Liver and respiratory co-morbidity were associated with significantly lower 25-OH values and renal co-morbidity with significantly lower 1,25-OH2 values. No significant differences of 1,25-OH2 or 25-OH between different pathogens (influenza virus, Legionella spp., Streptococcus pneumoniae) were detected.

CONCLUSION

For 1,25-OH2, we found a significant and independent (controlled for age, season and pathogen) negative correlation to pneumonia severity. Therefore, supplementation of non-activated vitamin D to protect from pneumonia may be non-sufficient in patients that have a decreased capacity to hydroxylate 25-OH to 1,25-OH2.

Is there an association between periprosthetic joint infection and low vitamin D levels?

PURPOSE

Vitamin D is increasingly being recognized as an important mediator of immune function and may have a preventive role in the pathogenesis of periprosthetic joint infection. To the best of our knowledge, no other study has examined possible associations between periprosthetic joint infection and vitamin D deficiency. We investigated the rate of vitamin D deficiency in patients treated for periprosthetic joint infection and whether vitamin D deficiency is independent of other risk factors for vitamin D deficiency in patients with periprosthetic joint infection.

METHODS

Serum 25-hydroxyvitamin D (25OHD) levels of every patient scheduled to receive a total prosthesis either of the hip, knee, or shoulder in the orthopaedic department of the Johannes-Guttenberg-University Hospital in Mainz, Germany (109 patients), were measured after admission. Furthermore, serum 25OHD levels were measured for every patient presenting with periprosthetic joint infection (n = 50) or aseptic loosening of the prosthesis (n = 31) scheduled to undergo revision surgery. The prevalence of normal (> 30 ng/ml), insufficient (20-30 ng/ml), and deficient (<20 ng/ml) 25OHD levels was determined.

RESULTS

All tested patient subgroups showed low vitamin D levels. Statistical analysis found no significant difference in vitamin D levels comparing patients with prosthesis and patients with aseptic prosthesis loosening (p = 0.58). Significant differences in 25OHD levels were found comparing patients with periprosthetic joint infection and patients scheduled for primary arthroplasty (p < 0.001). In addition, we found a significant difference (p < 0,001) in 25OHD levels of patients with periprosthetic joint infection compared with patients with aseptic prosthesis loosening.

CONCLUSION

We found a high frequency of vitamin D deficiency in patients being treated by primary arthroplasty and those with aseptic joint prosthetic loosening and periprosthetic joint infection. Vitamin D deficiency was severe in patients with periprosthetic joint infection.

Vitamin D: a new anti-infective agent?

Before the antibiotic era, treatment of tuberculosis patients was restricted to sun exposure in sanatoria. Years later, it was found that 1,25-dihydroxyvitamin D3 stimulates production of cathelicidins, a family of polypeptides found in lysosomes of macrophages and polymorphonuclear leukocytes. Cathelicidins serve a critical role in innate immune defense, which plays an important role in the suppression of Mycobacterium infections and other pathogens. It is believed that the increased incidence of the common cold and pneumonia during winter is related, in part, to decreased exposure to sunlight, resulting in a decreased synthesis of 1,25-dihydroxyvitamin D3. An association has been established between low levels of vitamin D and upper respiratory and enteric infections, pneumonia, otitis media, Clostridium infections, vaginosis, urinary tract infections, sepsis, influenza, dengue, hepatitis B, hepatitis C, and HIV infections. Accumulating evidence suggests that 1,25-dihydroxyvitamin D3 exerts protective effects during infections by upregulating the expression of cathelicidin and β-defensin 2 in phagocytes and epithelial cells. Vitamin D may be acting as a panaceal antibiotic agent and thus may be useful as an adjuvant therapy in diverse infections.

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 bloodstream infections

BACKGROUND

Alterations in immune function can predispose patients to nosocomial infections. Few studies have explored potentially modifiable host factors that may improve immune function and decrease risk of hospital-acquired bloodstream infection (HABSI). Vitamin D is a key regulator of innate and adaptive immune systems that may influence host susceptibility to infections.

OBJECTIVE

We investigated the association between prehospital serum 25-hydroxyvitamin D [25(OH)D] concentrations and risk of HABSI.

DESIGN

We performed a retrospective cohort study of 2135 adult patients from 2 Boston teaching hospitals. All patients had 25(OH)D concentrations measured before hospitalization between 1993 and 2010. The main outcome measure was HABSI, which was defined as positive blood cultures from samples drawn 48 h after hospital admission. Coagulase-negative Staphylococcus isolates were not considered to be bloodstream infections. Associations between 25(OH)D groups and HABSI were estimated by using bivariable and multivariable logistic regression models. Adjusted ORs were estimated with the inclusion of covariate terms thought to plausibly interact with both 25(OH)D concentration and HABSI.

RESULTS

Compared with patients with 25(OH)D concentrations ≥30 ng/mL, patients with concentrations <30 ng/mL had higher odds of HABSI. For 25(OH)D concentrations <10 ng/mL, the OR was 2.33 (95% CI: 1.45, 3.74); for 25(OH)D concentrations from 10 to 19.9 ng/mL, the OR was 1.60 (95% CI: 1.04, 2.46); and for 25(OH)D concentrations from 20 to 29.9 ng/mL, the OR was 1.13 (95% CI: 0.69, 1.84). After adjustment for age, sex, race (nonwhite compared with white), patient type (medical compared with surgical), and Deyo-Charlson index, the ORs of HABSI were 1.95 (95% CI: 1.22, 3.12), 1.36 (95% CI: 0.89, 2.07), and 0.98 (95% CI: 0.60, 1.62), respectively.

CONCLUSIONS

The analysis of 2135 adult patients showed that 25(OH)D concentrations <10 ng/mL before hospitalization were associated with significantly increased odds of developing HABSI. These data support the initiation of randomized trials to test the role of vitamin D supplementation in HABSI prevention.

Serum 1,25-dihydroxyvitamin D: an outcome prognosticator in human sepsis

In sepsis, the vitamin D active metabolite 1,25-dihydroxyvitamin D (1,25(OH)₂D) may play a crucial role by its action to produce cathelicidin and improve endothelial barrier function, such that a deficiency in 1,25(OH)₂D is associated with poor outcome. To test our hypothesis, we performed analysis of stored plasma samples from a prospective observational study in 91 patients with sepsis, age of 59.1+/−2.0 years, 52.7% females, and 11.0% deaths at 30 days. Vitamin D status, including 25-hydroxyvitamin D (25(OH)D), 1,25(OH)₂D, 24,25-dihydroxyvitamin D (24,25(OH)₂D), and parathyroid hormone (PTH), were measured daily over 3 days after hospital admission. At baseline, 1,25(OH)₂D was significantly different between survivors vs. non-survivors. But there was no significant difference in 25(OH)D, 24,25(OH)₂D, and PTH. In a multivariable binomial logistic regression model, age, total calcium and 1,25(OH)₂D were significant predictors of 30-day mortality. Kaplan Meier analysis showed that patients with mean 1,25(OH)₂D measured over 3 days of < = 13.6 pg/mL had 57.1% 30-day survival compared to 91.7% in patients with 1,25 (OH)₂D level >13.6 pg/mL (p<0.01). From repeated measures regression analysis, there was significant increase in 1,25(OH)₂D for increases in 25(OH)D in both survivors and non-survivors. However, compared to survivors, the low 25(OH)D in non-survivors was insufficient to account for the larger decrease in 1,25(OH)₂D, indicating a dysfunctional 1α-hydroxylase. Additionally, there was a significant negative correlation between PTH and 1,25(OH)₂D in both survivors and non-survivors, suggesting a severe impairment in the effect of PTH to increase renal 1α-hydroxylase activity. In conclusion, low 1,25(OH)₂D levels are associated with increased 30-day mortality in sepsis patients, likely due to impaired 25(OH)D hydroxylation and PTH insensitivity. Our data also suggest that the active metabolite 1,25(OH)₂D may be an important therapeutic target in the design of sepsis clinical trials.

Low vitamin D concentration is not associated with increased mortality and morbidity after cardiac surgery

Objective

To determine the effect of vitamin D on postoperative outcomes in cardiac surgical patients.

Design

Retrospective study.

Setting

Single institution-teaching hospital.

Participants

Adult cardiac surgical patients with perioperative 25-hydroxyvitamin D measurements.

Interventions

None. We gathered information from the Cardiac Anesthesiology Registry that was obtained at the time of the patients’ visit/hospitalization.

Measurements and Main Results

We used data of 18,064 patients from the Cardiac Anesthesiology Registry; 426 patients with 25-hydroxyvitamin D measurements met our inclusion criteria. Association with Vitamin D concentration and composite of 11 cardiac morbidities was done by multivariate (i.e., multiple outcomes per subject) analysis. For other outcomes separate multivariable logistic regressions and adjusting for the potential confounders was used. The observed median vitamin D concentration was 19 [Q1-Q3∶12, 30] ng/mL. Vitamin D concentration was not associated with our primary composite of serious cardiac morbidities (odds ratio [OR], 0.96; 95% CI, 0.86–1.07). Vitamin D concentration was also not associated with any of the secondary outcomes: neurologic morbidity (P = 0.27), surgical (P = 0.26) or systemic infections (P = 0.58), 30-day mortality (P = 0.55), or length of initial intensive care unit (ICU) stay (P = 0.04).

Conclusions

Our analysis suggests that perioperative vitamin D concentration is not associated with clinically important outcomes, likely because the outcomes are overwhelmingly determined by other baseline and surgical factors.

1α,25-Dihydroxyvitamin D(3) inhibits vascular cellular adhesion molecule-1 expression and interleukin-8 production in human coronary arterial endothelial cells

Kawasaki disease is an acute febrile vasculitis of childhood that is associated with elevated production of inflammatory cytokines, causing damage to the coronary arteries. The production of proinflammatory cytokines and expression of adhesion molecules in human coronary arterial endothelial cells (HCAECs) is regulated by nuclear transcription factor-κB (NF-κB) activation. We have previously reported that the active form of vitamin D, 1α,25-dihydroxyvitamin D(3) (1α,25-(OH)(2)D(3)), inhibits tumor necrosis factor-α (TNF-α)-induced NF-κB activation. In this study, we examined the anti-inflammatory effects of 1α,25-(OH)(2)D(3) on TNF-α-induced adhesion molecule expression (vascular cellular adhesion molecule-1 (VCAM-1) and intercellular adhesion molecule-1 (ICAM-1)) and cytokine production (interleukin-6 (IL-6) and IL-8) in HCAECs. Pretreatment with 1α,25-(OH)(2)D(3) significantly inhibited TNF-α-induced VCAM-1 expression and IL-8 production in HCAECs. Our results suggest that adjunctive 1α,25-(OH)(2)D(3) therapy may modulate the inflammatory response during Kawasaki disease vasculitis.

Effects of endotoxemia on the pharmacodynamics and pharmacokinetics of ketamine and xylazine anesthesia in Sprague-Dawley rats

Purpose

To evaluate the effects of endotoxemia on the pharmacokinetics and pharmacodynamics of ketamine and xylazine anesthesia in Sprague-Dawley rats.

Methods

Sprague-Dawley rats received ketamine (80 mg/kg) and xylazine (5 mg/kg) intramuscularly following the intraperitoneal administration of different lipopolysaccharide concentrations (1, 10, and 100 µg/kg) to simulate different levels of endotoxemia. Results were compared to control animals receiving saline intraperitoneally. During anesthesia, a toe pinch was performed to evaluate anesthesia duration, and selected physiological parameters (heart and respiratory rates, oxygen saturation, and rectal temperature) were taken. Blood samples were also taken during anesthesia at selected time points for the analysis of plasmatic ketamine and xylazine concentrations by liquid chromatography-mass spectrometry. Blood samples were taken 1 week prior to and 24 hours following anesthesia for blood biochemistry.

Results

Anesthesia duration significantly increased for moderate (10 µg/kg) and high (100 µg/kg) lipopolysaccharide groups. Liver histopathology showed minor to moderate necrosis in all lipopolysaccharide groups in some animals. The most important physiological change that occurred was a decrease in oxygen saturation, and for blood biochemistry a decrease in serum albumin. Ketamine pharmacokinetics were not affected except for the moderate (10 µg/kg) lipopolysaccharide group where a decrease in the area under the plasma concentration-time curve from time zero to the last measurable concentration, a decrease in half-life, and an increase in the clearance were observed. For xylazine, the area under the plasma concentration-time curve increased and the clearance decreased in the moderate (10 µg/kg) and high (100 µg/kg) lipopolysaccharide groups.

Conclusion

During ketamine-xylazine anesthesia, endotoxemia may alter xylazine pharmacokinetics and selected biochemical and physiological parameters, suggesting that anesthetic drug dosages could be modified for a more rapid recovery.

Vitamin D and sepsis: An emerging relationship

Vitamin D insufficiency and sepsis are both highly prevalent worldwide problems and this article reviews the emerging science that is defining the intersections of these conditions. The importance of vitamin D’s role in skeletal health has long been understood but recent evidence is beginning to highlight its role in the functioning of other physiologic systems of the body. Basic science data reveal its integral role in local immune responses to pathogens and the systemic inflammatory pathways of sepsis. Furthermore, clinical scientists have found associations with respiratory infections, critical illness and sepsis but the causal relationship and its clinical impact have yet to be clearly defined. The article ends with speculations on the connections between racial disparities and seasonal differences in sepsis and vitamin D insufficiency.

Impact of vitamin D3 on cardiovascular responses to glucocorticoid excess

Although the cardiovascular system is not a classical target for 1,25-dihydroxyvitamin D3, both cardiac myocytes and vascular smooth muscle cells respond to this hormone. The present study aimed to elucidate the effect of active vitamin D3 on cardiovascular functions in rats exposed to glucocorticoid excess. Adult male Wistar rats were allocated into three groups: control group, dexamethasone (Dex)-treated group receiving Dex (200 μg/kg) subcutaneously for 12 days, and vitamin D3-Dex-treated group receiving 1,25-(OH)2D3 (100 ng/kg) and Dex (200 μg/kg) subcutaneously for 12 days. Rats were subjected to measurement of systolic (SBP), diastolic (DBP), and mean arterial (MAP) blood pressures and heart rate. Rate pressure product (RPP) was calculated. Rats' isolated hearts were perfused in Langendorff preparation and studied for basal activities (heart rate, peaked developed tension, time to peak tension, half relaxation time, and myocardial flow rate) and their responses to isoproterenol infusion. Blood samples were collected for determination of plasma level of nitrite, nitric oxide surrogate. Dex-treated group showed significant increase in SBP, DBP, MAP, and RPP, as well as cardiac hypertrophy and enhancement of basal cardiac performance evidenced by increased heart rate, rapid and increased contractility, and accelerated lusitropy, together with impaired contractile and myocardial flow rate responsiveness to beta-adrenergic activation and depressed inotropic and coronary vascular reserves. Such alterations were accompanied by low plasma nitrite. These changes were markedly improved by vitamin D3 treatment. In conclusion, vitamin D3 is an efficacious modulator of the deleterious cardiovascular responses induced by glucocorticoid excess, probably via accentuation of nitric oxide.

Vitamin D in sepsis: from basic science to clinical impact

The growing basic and clinical investigations into the extraskeletal effects of vitamin D have revealed roles in the functioning of the immune system, generating interesting questions about this nutrient's connections to sepsis. This article briefly reviews the current science of the function of vitamin D in the immune system as well as the emerging clinical literature regarding its associations with respiratory infections, sepsis, and critical illness. Finally, we offer views on the potential future directions for research in the field by outlining potential relevant scenarios and outcomes.

The immunoregulatory function of vitamin D: implications in chronic kidney disease

Cardiovascular and infectious diseases remain the most common causes of death among patients with chronic kidney disease (CKD) and end-stage renal disease (ESRD). Basic science and epidemiological studies indicate that vitamin D has importance not only for cardiovascular health, but also for the immune response. Vitamin D signaling pathways regulate both innate and adaptive immunity, maintaining the associated inflammatory response within physiological limits. Levels of both the inactive as well as active form of vitamin D (25-hydroxyvitamin D and 1,25-dihydroxyvitamin D, respectively) are decreased in patients with CKD and ESRD. It is reasonable to hypothesize, therefore, that the immune dysfunction associated with vitamin D deficiency in patients with CKD and ESRD in part explains the misdirected inflammatory response and increased susceptibility to infection seen in this population. Indeed, observational studies show that vitamin D deficiency in patients with ESRD is associated with increased mortality, and treatment with vitamin D is associated with a decreased risk of infection, as well as reduced all-cause mortality. However, whether different vitamin D preparations have differential effects on physiological function and clinical outcomes is still unclear. A proper understanding of the immune regulatory function of vitamin D is important for the development of future therapeutic strategies.

Translating the role of vitamin D3 in infectious diseases

Vitamin D(3) affects both the innate as well as adaptive immune responses. Epidemiological studies have established that vitamin D(3) deficiency plays an important role in tuberculosis (TB) and viral influenza prevalence as well as susceptibility to active disease in TB. Vitamin D(3) status has been associated with the clinical course of HIV infection and drug interaction with anti-retroviral therapy. This article reviews the immunomodulatory capacity of vitamin D(3) and examines the impact of vitamin D(3) supplementation as a preventive or therapeutic intervention with the intent to uncover its potential therapeutic application in infectious diseases and to identify novel areas for future research. We present a review of randomized, controlled clinical studies conducted in humans which included assessment of the immune function or clinical outcome as study end points. Current data support vitamin D(3) supplementation as risk-modifying intervention in tuberculosis and viral respiratory tract infection, but the optimal dosage regimen remains to be determined. However, to date the knowledge on its role in fungal infection and sepsis is limited although a potential benefit could be harnessed from its ability to curtail the unrestrained pro-inflammatory response and therefore prevent excessive collateral tissue damage.

Vitamin D status and expression of vitamin D receptor and LL-37 in patients with spontaneous bacterial peritonitis

BACKGROUND

Vitamin D, which exerts its effect through vitamin D receptor (VDR), and LL-37, a vitamin D-dependent antimicrobial peptide, are involved in many infectious diseases.

AIM

The objective of this study was to evaluate whether vitamin D status and expressions of VDR and LL-37 are involved in the pathogenesis of spontaneous bacterial peritonitis (SBP).

METHODS

Serum and ascitic fluid 25-dihydroxyvitamin D [25(OH)D] concentrations and levels of VDR and LL-37 in peritoneal leukocytes were measured by ELISA and real-time PCR methods in cirrhotic patients with SBP (n = 19) and cirrhotic patients with simple ascites (n = 28). The correlations between these levels and clinical variables were evaluated.

RESULTS

Cirrhotic patients with ascites showed low vitamin D concentrations in both serum and ascitic fluid. Lower serum vitamin D concentrations were observed in cirrhotic patients with Child-Pugh C class. 25(OH)D concentrations in ascitic fluid were positive correlated with that in serum (r = 0.74, P < 0.001). The SBP group showed significantly higher levels of both VDR and LL-37 mRNA expressions in peritoneal leukocytes than the simple ascites group (P = 0.005 and P = 0.003, respectively). In the SBP group, VDR and LL-37 expressions in peritoneal leukocytes were positively correlated (r = 0.70, P = 0.001).

CONCLUSIONS

Vitamin D insufficiency was universal among cirrhotic patients with ascites, and the situation was more severe with more serious cirrhosis. Expressions of peritoneal leukocytes VDR and LL-37 genes were simultaneously up-regulated in cirrhotic patients with SBP when compared with cirrhotic patients with simple ascites. It is indicated that the vitamin D-VDR system and its downstream gene, LL-37, are involved in the pathogenesis and antibacterial immune response to SBP.

Effect of recombinant interleukin-10 on some haematological and biochemical parameters in a rat endotoxaemic model

Recombinant interleukin-10 (rIL10) has been found to suppress the synthesis of tumour necrosis factor (TNF), interleukin-1 (IL-1), interleukin-6 (IL-6) and tissue factor and to improve survival from experimental sepsis. The aim of this study was to evaluate the protective effect of rIL-10 on lipopolysaccharide-(LPS-) induced haematological and biochemical disturbances in rats. In the present study, 40 rats were used and divided equally into four groups. Group 1 (control group, C) was treated with 0.9% saline. Group 2: LPS was injected intravenously (1.6 mg/100 g), Group 3 received rIL10 treatment (125 μg/kg) 2 min before 0.9% saline injection, Group 4 received rIL10 treatment 2 min before endotoxin treatment. When compared with the controls, platelet count, leukocyte count (with a marked neutrophilia and lymphopenia) and fibrinogen were decreased, while activated partial thromboplastin time (APTT) and prothrombin time (PT) were prolonged in the endotoxaemic rats. In addition, LPS caused statistically significant increases in plasma aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activities as well as creatinine, cholesterol and triglyceride concentrations, while it caused a statistically significant decrease in glucose, total protein and albumin levels as compared to the control group. On the other hand, rIL10 significantly suppressed disturbances in the haematological and biochemical parameters associated with endotoxaemia. As a result, rIL10 may be efficacious in preventing haematological disorders, tissue damage and changes in lipid, protein and carbohydrate metabolism in endotoxaemia.

Vitamin D insufficiency and sepsis severity in emergency department patients with suspected infection

OBJECTIVES

Vitamin D is increasingly recognized as an important mediator of immune function and may have a preventive role in the pathogenesis of sepsis. We sought to evaluate the association between vitamin D status and sepsis severity and hypothesized that vitamin D insufficiency would be associated with increased sepsis severity.

METHODS

This was a pilot study of emergency department (ED) patients age ≥ 18 years evaluated for suspected infection at an urban, teaching hospital. The authors measured illness severity using the following assessments at baseline and 24 hours: 1) severe sepsis, defined as suspected infection plus two or more elements of systemic inflammatory response syndrome criteria and acute dysfunction of one or more organ systems; 2) Acute Physiology Age Chronic Health Evaluation (APACHE) II scores; and 3) Sepsis-related Organ Failure Assessment (SOFA) scores. Vitamin D insufficiency was defined as baseline serum 25-hydroxyvitamin D (25OHD) levels <75 nmol/L.

RESULTS

Eighty-one patients were enrolled, with a median age of 62 years (interquartile range [IQR] = 48-76 years), 47% were female, and 77% were white. At baseline, 64 (79%) had 25OHD levels of <75 nmol/L, and 43 (53%) had severe sepsis. At 24 hours, 48 (59%) had severe sepsis. Patients with baseline 25OHD levels of <75 nmol/L, compared to patients with 25OHD levels of ≥ 75 nmol/L, were more likely to have severe sepsis (61% vs. 24%; p = 0.006) and SOFA scores ≥ 2 (44% vs. 18%; p = 0.049). Additionally, at 24 hours, those with 25OHD levels of <75 nmol/L were more likely to have severe sepsis (67% vs. 29%; p = 0.005), dysfunction of two or more organ systems (50% vs. 18%; p = 0.02), APACHE II score of ≥ 25 (19% vs. 0%; p = 0.06), and SOFA scores of ≥ 2 (63% vs. 29%; p = 0.02). Additionally, all four patients who died during the index hospitalization had 25OHD levels of <75 nmol/L.

CONCLUSIONS

Vitamin D insufficiency was associated with higher sepsis severity in ED patients hospitalized for suspected infection. Larger observational studies, mechanistic studies, and ultimately randomized controlled trials are needed to determine causation and to evaluate if vitamin D supplementation can reduce the risk of sepsis as a preventive or therapeutic strategy.

Toll-like receptor 4 modulation as a strategy to treat sepsis

Despite a decrease in mortality over the last decade, sepsis remains the tenth leading causes of death in western countries and one of the most common cause of death in intensive care units. The recent discovery of Toll-like receptors and their downstream signalling pathways allowed us to better understand the pathophysiology of sepsis-related disorders. Particular attention has been paid to Toll-like receptor 4, the receptor for Gram-negative bacteria outer membrane lipopolysaccharide or endotoxin. Since most of the clinical trial targeting single inflammatory cytokine in the treatment of sepsis failed, therapeutic targeting of Toll-like receptor 4, because of its central role, looks promising. The purpose of this paper is to focus on the recent data of various drugs targeting TLR4 expression and pathway and their potential role as adjunctive therapy in severe sepsis and septic shock.

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

Background

Vitamin D insufficiency is common in hospitalized patients. Recent evidence suggests that vitamin D may enhance the innate immune response by induction of cathelicidin (LL-37), an endogenous antimicrobial peptide produced by macrophages and neutrophils. Thus, the relationship between vitamin D status and LL-37 production may be of importance for host immunity, but little data is available on this subject, especially in the setting of human sepsis syndrome and other critical illness.

Methods

Plasma concentrations of 25-hydroxyvitamin D (25(OH)D), vitamin D binding protein (DBP) and LL-37 in critically ill adult subjects admitted to intensive care units (ICUs) with sepsis and without sepsis were compared to healthy controls.

Results

Critically ill subjects had significantly lower plasma 25(OH)D concentrations compared to healthy controls. Mean plasma LL-37 levels were significantly lower in critically ill subjects compared to healthy controls. Vitamin D binding protein levels in plasma were significantly lower in critically ill subjects with sepsis compared to critically ill subjects without sepsis. There was a significant positive association between circulating 25(OH)D and LL-37 levels.

Conclusion

This study demonstrates an association between critical illness and lower 25(OH)D and DBP levels in critically ill patients as compared to healthy controls. It also establishes a positive association between vitamin D status and plasma LL-37, which suggests that systemic LL-37 levels may be regulated by vitamin D status. Optimal vitamin D status may be important for innate immunity especially in the setting of sepsis. Further invention studies to examine this association are warranted.