Vitamin D is a fat-soluble regulatory vitamin maintaining blood calcium and phosphorus concentrations within a narrow physiological range. Binding to an appropriate delivery system can enhance ...vitamin D3 solubility, simplify its transport, protect it from degradation and increase its bioavailability. Alpha-lactalbumin as a milk protein is a good candidate for a vitamin encapsulation. Binding properties and conformational change of bovine apo alpha-lactalbumin upon interaction with vitamin D3 were investigated by calorimetry, spectroscopy and by molecular docking. Tryptophan fluorescence quenching indicates that the protein conformation changes in the presence of vitamin D3. However, according to far UV CD results, the secondary structure of the protein was altered in the presence of vitamin D3. The molecular modeling showed that Van der Waals interactions, hydrogen bond and hydrophobic interactions play a major role in the binding of vitamin D3 to the alpha-lactalbumin hydrophobic pocket. The particle size of alpha-lactalbumin and vitamin D3 complex is much larger than the native protein. Surprisingly, in the presence of vitamin D3, the thermal stability of the protein decreases. The binding constant and standard Gibbs free energy change (ΔG°) of binding vitamin D3 to the protein obtained from ITC are 3.66 × 105 M−1 and −7.6 kcal mol−1, respectively, what agrees with results obtained by measurement of fluorescence and by molecular docking. The formed complex is a suitable candidate in order to enrich the low-fat food and non-alcohol drinks. According to the results, alpha-lactalbumin can be introduced suitable carrier for vitamin D3.
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•α-La can be introducedsuitable carrier for encapsulation of vitamin D3.•α-La contains one binding site for vitamin D3.•The particle size of complex formed between α-La and vitamin is much larger than the native protein.•The conformation of protein changes and hydrophobic surface of the α-La increases.•Complex formation decreases the heat stability of the protein.
A physiologically based pharmacokinetic (PBPK) model of vitamin D
and metabolites 25(OH)D
, 1,25(OH)
D
, and 24,25(OH)
D
is presented. In this study, patients with 25(OH)D
plasma concentrations ...below 30 ng/ml were studied after a single dose of 5000 I.U. (125
g) cholecalciferol, provided with 5000 I.U. daily cholecalciferol supplementation until vitamin D replete 25(OH)D
plasma concentrations above 30 ng/ml, and had serial plasma samples were collected at each phase for 14 days. Total concentrations of vitamin D
and metabolites were measured by ultra-high performance liquid chromatography tandem mass spectrometry. A nine-compartment PBPK model was built using MATLAB to represent the triphasic study nature (insufficient, replenishing, and sufficient). The stimulatory and inhibitory effect of 1,25(OH)
D
were incorporated by fold-changes in the primary metabolic enzymes CYP27B1 and CYP24A1, respectively. Incorporation of dynamic adipose partition coefficients for vitamin D
and 25(OH)D
and variable enzymatic reactions aided in model fitting. Measures of model predictions agreed well with data from metabolites, with 97%, 88%, and 98% of the data for 25(OH)D
, 24,25(OH)
D
, and 1,25(OH)
D
, respectively, within twofold of unity (
values between 0.5 and 2.0). Bootstrapping was performed and optimized parameters were reported with 95% confidence intervals. This PBPK model could be a useful tool for understanding the connections between vitamin D and its metabolites under a variety of clinical situations. SIGNIFICANCE STATEMENT: This study developed a physiologically based pharmacokinetic (PBPK) model of vitamin D
and metabolites for patients moving from an insufficient to a repleted state over a period of 16 weeks.
By modulating the antiviral immune response via vitamin D receptor, the active form of vitamin D (1,25-dihydroxyvitamin D, calcitriol) could play a central role in protection against respiratory ...virus infections. This in vitro study tested the hypothesis that respiratory viruses modulate vitamin D receptor expression in human bronchial epithelial cells and this modulation affects the antiviral response to exogenous vitamin D.
Human primary bronchial epithelial cells were infected with rhinoviruses and respiratory syncytial virus in the presence or absence of vitamin D. Expression of vitamin D receptor, 1α-hydroxylase (1α(OH)ase), 24-hydroxylase (24(OH)ase), innate interferons, interferon stimulated genes and cathelicidin were measured by quantitative polymerase chain reaction. The antiviral effect of vitamin D on rhinovirus replication was determined by measurement of virus load. A direct inactivation assay was used to determine the antiviral activity of cathelicidin.
Both RV and RSV decreased vitamin D receptor and 24(OH)ase and, in addition, RSV increased 1α(OH)ase expression in epithelial cells. Vitamin D decreased rhinovirus replication and release, and increased rhinovirus-induced interferon stimulated genes and cathelicidin. Furthermore, cathelicidin had direct anti-rhinovirus activity.
Despite lower vitamin D receptor levels in rhinovirus-infected epithelial cells, exogenous vitamin D increased antiviral defences most likely via cathelicidin and innate interferon pathways.
•We analyse the antirhinovial effect of calcitriol in vitro.•Calcitriol increases antimicrobial protein cathelicidin in primary respiratory bronchial epithelial cells.•Calcitriol decreases rhinovirus replication in respiratory epithelial cells.
Genetic forms of vitamin D-dependent rickets (VDDRs) are due to mutations impairing activation of vitamin D or decreasing vitamin D receptor responsiveness. Here we describe two unrelated patients ...with early-onset rickets, reduced serum levels of the vitamin D metabolites 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D, and deficient responsiveness to parent and activated forms of vitamin D. Neither patient had a mutation in any genes known to cause VDDR; however, using whole exome sequencing analysis, we identified a recurrent de novo missense mutation, c.902T>C (p.I301T), in CYP3A4 in both subjects that alters the conformation of substrate recognition site 4 (SRS-4). In vitro, the mutant CYP3A4 oxidized 1,25-dihydroxyvitamin D with 10-fold greater activity than WT CYP3A4 and 2-fold greater activity than CYP24A1, the principal inactivator of vitamin D metabolites. As CYP3A4 mutations have not previously been linked to rickets, these findings provide insight into vitamin D metabolism and demonstrate that accelerated inactivation of vitamin D metabolites represents a mechanism for vitamin D deficiency.
The efficacy of vitamin D3 supplementation in coronavirus disease 2019 (COVID-19) remains unclear.
To investigate the effect of a single high dose of vitamin D3 on hospital length of stay in patients ...with COVID-19.
This was a multicenter, double-blind, randomized, placebo-controlled trial conducted in 2 sites in Sao Paulo, Brazil. The study included 240 hospitalized patients with COVID-19 who were moderately to severely ill at the time of enrollment from June 2, 2020, to August 27, 2020. The final follow-up was on October 7, 2020.
Patients were randomly assigned to receive a single oral dose of 200 000 IU of vitamin D3 (n = 120) or placebo (n = 120).
The primary outcome was length of stay, defined as the time from the date of randomization to hospital discharge. Prespecified secondary outcomes included mortality during hospitalization; the number of patients admitted to the intensive care unit; the number of patients who required mechanical ventilation and the duration of mechanical ventilation; and serum levels of 25-hydroxyvitamin D, total calcium, creatinine, and C-reactive protein.
Of 240 randomized patients, 237 were included in the primary analysis (mean SD age, 56.2 14.4 years; 104 43.9% women; mean SD baseline 25-hydroxyvitamin D level, 20.9 9.2 ng/mL). Median (interquartile range) length of stay was not significantly different between the vitamin D3 (7.0 4.0-10.0 days) and placebo groups (7.0 5.0-13.0 days) (log-rank P = .59; unadjusted hazard ratio for hospital discharge, 1.07 95% CI, 0.82-1.39; P = .62). The difference between the vitamin D3 group and the placebo group was not significant for in-hospital mortality (7.6% vs 5.1%; difference, 2.5% 95% CI, -4.1% to 9.2%; P = .43), admission to the intensive care unit (16.0% vs 21.2%; difference, -5.2% 95% CI, -15.1% to 4.7%; P = .30), or need for mechanical ventilation (7.6% vs 14.4%; difference, -6.8% 95% CI, -15.1% to 1.2%; P = .09). Mean serum levels of 25-hydroxyvitamin D significantly increased after a single dose of vitamin D3 vs placebo (44.4 ng/mL vs 19.8 ng/mL; difference, 24.1 ng/mL 95% CI, 19.5-28.7; P < .001). There were no adverse events, but an episode of vomiting was associated with the intervention.
Among hospitalized patients with COVID-19, a single high dose of vitamin D3, compared with placebo, did not significantly reduce hospital length of stay. The findings do not support the use of a high dose of vitamin D3 for treatment of moderate to severe COVID-19.
ClinicalTrials.gov Identifier: NCT04449718.
We report a new sensitive label-free electrochemical immunosensor to detect Vitamin D3 (25-OHD3) in untreated serum samples. To this aim, a graphite screen printed electrode (SPE) was modified using ...cysteamine (CYM) functionalized core-shell magnetic nanoparticles (Au@MNPs) then, the 25-OHD3 antibody (AbD) was immobilized via glutaraldehyde crosslinking. The several steps involved in the immunosensor development and 25-OHD3 analysis were monitored by using differential pulse voltammetry (DPV). The developed immunosensor showed a LOD of 2.4 ng mL−1 and a linear range between 7.4 and 70 ng mL−1. The effectiveness of the immunosensor in human serum analysis was assessed by comparing the results obtained with the chemiluminescence-immunoassay (CLIA) reference method. The high sensitivity and excellent agreement with the reference method suggest its potential use as a POCT to monitor hypovitaminosis 25-OHD levels.
Scheme of assembly of the Au@MNPs-based 25(OH)D3 immunosensor. Display omitted
•Cysteamine (CYM) functionalization of gold magnetic nanoparticles (AuMNPs) for the modification of graphite-SPE electrodes.•Development of site-directed antibody immobilization-based electrochemical immunosensor for quick and simple detection of Vitamin D3.•Optimized nanostructured-based electrochemical immunosensor for Vitamin D3 detection as POCT for fast hypovitaminosis D diagnosis.
Mechanisms linking ingested pollutants to increased incidence of allergy are poorly understood. We report that mice exposed to low doses of cadmium develop higher IgE responses following oral ...allergen sensitization and more severe allergic symptoms upon allergen challenge. The environmentally relevant doses of this pollutant also induced oxidative/inflammatory responses in the gut of SPF, but not germ-free mice. Interestingly, the increased IgE responses correlated with stimulation of the vitamin D
-metabolizing enzymes CYP27B1 and CYP24A1 in the gut and increased luminal levels of oxidized vitamin D
metabolites that are not ligands of the vitamin D receptor. Inhibition of CYP27B1 and CYP24A1 via oral administration of pharmacological inhibitors reduced IgE responses induced in mice orally exposed to cadmium. Our findings identify local alteration of vitamin D signaling as a new mechanism for induction of IgE responses by environmental pollutants. They also identify vitamin D3-metabolizing enzymes as therapeutic targets for the treatment of allergy.
AbstractObjectiveTo investigate whether vitamin D supplementation is associated with lower mortality in adults.DesignSystematic review and meta-analysis of randomised controlled trials.Data ...sourcesMedline, Embase, and the Cochrane Central Register from their inception to 26 December 2018.Eligibility criteria for selecting studiesRandomised controlled trials comparing vitamin D supplementation with a placebo or no treatment for mortality were included. Independent data extraction was conducted and study quality assessed. A meta-analysis was carried out by using fixed effects and random effects models to calculate risk ratio of death in the group receiving vitamin D supplementation and the control group.Main outcome measuresAll cause mortality.Results50 trials with a total of 74 655 participants were identified. Vitamin D supplementation was not associated with all cause mortality (risk ratio 0.98, 95% confidence interval 0.95 to 1.02, I2=0%), cardiovascular mortality (0.98, 0.88 to 1.08, 0%), or non-cancer, non-cardiovascular mortality (1.05, 0.93 to 1.18, 0%). Vitamin D supplementation statistically significantly reduced the risk of cancer death (0.85, 0.74 to 0.97, 0%). In subgroup analyses, all cause mortality was significantly lower in trials with vitamin D3 supplementation than in trials with vitamin D2 supplementation (P for interaction=0.04); neither vitamin D3 nor vitamin D2 was associated with a statistically significant reduction in all cause mortality.ConclusionsVitamin D supplementation alone was not associated with all cause mortality in adults compared with placebo or no treatment. Vitamin D supplementation reduced the risk of cancer death by 15%. Additional large clinical studies are needed to determine whether vitamin D3 supplementation is associated with lower all cause mortality.Study registrationPROSPERO registration number CRD42018117823.
It is well known that cell can response to various chemical and mechanical stimuli. Therefore, flow pressure variation induced by sample loading and elution should be small enough to ignore the ...physical impact on cells when we use a Chip-SPE-MS system for cells. However, most existent Chip-SPE-MS systems ignored the pressure alternation because it is extremely difficult to develop a homogeneous-flow-pressure hyphenated module. Herein, we developed an interesting fluidic isolation-assisted homogeneous-flow-pressure Chip-SPE-MS system and demonstrated that it is adequate for online high-throughput determination and quantification of the 25-hydroxyvitamin D
(25(OH)D
) biotransformation in different cells. Briefly, the homogeneous ambient flow pressure is achieved by fluidic isolation between the cell culture channel and the SPE column, and an automatic sampling probe could accomplish the sample loading and dispensing to fulfill online pretreatment of the sample. Through this new system, the expression levels of 24,25-dihydroxyvitamin D
(24,25(OH)
D
) can be determined in real time with a detection limit of 2.54 nM. In addition, the results revealed that 25(OH)D
metabolic activity differed significantly between normal L-02 cells and cancerous HepG2 cells. Treatment of L-02 cells with a high dose of 25(OH)D
was found to increase significant formation of 24,25(OH)
D
, but this change was not apparent in HepG2 cells. The presented system promises to be a versatile tool for online accurate molecule biotransformation investigation and drug screening processes.
This study was conducted to evaluate the effects of 25-hydroxyvitamin Dsub.3 (25(OH)VDsub.3 ) and Vitamin Dsub.3 (VDsub.3 ) supplemented in the diet of weaned piglets on their growth performance, ...bone quality, intestinal integrity, immune function and antioxidant capacity. A total of 192 weaned piglets were allocated into four groups and they were fed a control diet containing 2000 IU VDsub.3 (negative control, NC), NC + 100 ppm colistin sulfate (positive control, PC), NC + 2000 IU VDsub.3 (VDsub.3 ) and NC + 2000 IU 25(OH)VDsub.3 (25(OH)VDsub.3 )sub.. The results showed that 25(OH)VDsub.3 improved the growth performance, bone quality and antioxidase activity of piglets compared with the other groups. Meanwhile, 25(OH)VDsub.3 up-regulated ileal mRNA expressions of tight junction proteins and host defense peptides. The VDsub.3 group had an increased intestinal sIgA content and mRNA expression of pBD-1 compared with the NC group. Both groups of VDsub.3 and 25(OH)VDsub.3 altered the microbial β-diversity compared with the NC group, and 25(OH)VDsub.3 increased ileal concentrations of acetate and butyrate. In conclusion, our findings indicated that a regular dosage of 2000 IU VDsub.3 in the weaned piglets' diet did not achieve optimal antioxidant capacity and immune function. 25(OH)VDsub.3 had better growth performance than VDsub.3 at the same inclusion level, which is associated with the improved intestinal integrity and antioxidant capacity.
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