Association of serum 25-hydroxyvitamins D2 and D3 with hearing loss in US adults: analysis from National Health and Nutrition Examination Survey, 2015-2016.

Background: Hearing loss (HL) is increasingly recognized as a significant global public health issue, and research on its relationship with vitamin D levels has gained wider attention. However, the association between serum biomarkers 25-hydroxyvitamin D2 (25(OH)D2) and D3 (25(OH)D3) with different types of HL remains unclear. This study aimed to investigate the potential association of serum 25(OH)D2 and 25(OH)D3 with HL in US adults. Methods: A sample of 3,684 individuals aged 20-69 years from the 2015-2016 National Health and Nutrition Examination (NHANES) was analyzed in this study. HL was defined as a pure tone average > 25 dB in either ear at low frequencies (500, 1,000, 2000 Hz), speech frequencies (500, 1,000, 2000, 4,000 Hz), and high frequencies (3,000, 4,000, 6,000, 8,000 Hz). Logistic regression was employed to examine the association between serum 25(OH)D2 and 25(OH)D3 and HL. The study population was then stratified by age, gender, race, and education level to analyze potential differences between adults in different subgroups. Results: In the multivariate analysis, it was found that serum 25(OH)D2 was independently associated with low-frequency hearing loss (LFHL) (OR: 1.012 [95% CI, 1.005-1.020]) and speech-frequency hearing loss (SFHL) (OR: 1.011 [95% CI, 1.003-1.018]). Restrictive cubic spline analysis demonstrated a linear dose-response relationship between serum 25(OH)D2 levels and LFHL (p for linearity <0.001), as well as SFHL (p for linearity = 0.001). Conversely, an L-shaped association was observed between serum 25(OH)D3 levels and both LFHL (p for nonlinearity = 0.014) and SFHL (p for nonlinearity = 0.025), with threshold values identified at 35.3 and 36.5 nmol/L, respectively. Higher levels of serum 25(OH)D3 were associated with a lower probability of high-frequency hearing loss (HFHL) (OR: 0.994 [95% CI, 0.989-0.999]), with a threshold value identified at 53.9 nmol/L. Furthermore, a significant interaction between diabetes and serum 25(OH)D2 in LFHL was revealed through subgroup analysis (p = 0.041). In the non-diabetic population, serum 25(OH)D2 maintained its association with LFHL. Conclusion: Our findings suggested a positive association between serum 25(OH)D2 concentrations and both LFHL and SFHL in the studied cohort. Additionally, an L-shaped relationship was found between serum 25(OH)D3 and LFHL and SFHL, and higher levels of serum 25(OH)D3 were identified to be associated with a lower risk of HFHL.

Vitamin D beyond blood: Tissue distribution of vitamin D metabolites after supplementation.

Vitamin D3's role in mineral homeostasis through its endocrine function, associated with the main circulating metabolite 25-hydroxyvitamin D3, is well characterized. However, the increasing recognition of vitamin D3's paracrine and autocrine functions-such as cell growth, immune function, and hormone regulation-necessitates examining vitamin D3 levels across different tissues post-supplementation. Hence, this review explores the biodistribution of vitamin D3 in blood and key tissues following oral supplementation in humans and animal models, highlighting the biologically active metabolite, 1,25-dihydroxyvitamin D3, and the primary clearance metabolite, 24,25-dihydroxyvitamin D3. While our findings indicate significant progress in understanding how circulating metabolite levels respond to supplementation, comprehensive insight into their tissue concentrations remains limited. The gap is particularly significant during pregnancy, a period of drastically increased vitamin D3 needs and metabolic alterations, where data remains sparse. Within the examined dosage ranges, both human and animal studies indicate that vitamin D3 and its metabolites are retained in tissues selectively. Notably, vitamin D3 concentrations in tissues show greater variability in response to administered doses. In contrast, its metabolites maintain a more consistent concentration range, albeit different among tissues, reflecting their tighter regulatory mechanisms following supplementation. These observations suggest that serum 25-hydroxyvitamin D3 levels may not adequately reflect vitamin D3 and its metabolite concentrations in different tissues. Therefore, future research should aim to generate robust human data on the tissue distribution of vitamin D3 and its principal metabolites post-supplementation. Relating this data to clinically appropriate exposure metrics will enhance our understanding of vitamin D3's cellular effects and guide refinement of clinical trial methodologies.

Relationship between 25-Hydroxyvitamin D3 Levels with Pain Intensity and Duration of Labor Stages in Primiparous Women.

Background: Prolonged labor is associated with various maternal and neonatal complications. This study aims to investigate the relationship between 25-hydroxyvitamin D3 levels and pain intensity and duration of labor stages in primiparous women. Materials and Methods: This cross-sectional study was conducted in Iran from November 2021 to January 2022 and comprised primiparous women who were in active labor after a term pregnancy (37-42 weeks). Five milliliter of blood was taken from each subject and centrifuged for the measurement of vitamin D level using the enzyme-linked immunosorbent assay method. The High-Performance Liquid Chromatography (HLPC) method was used to measure 25-OH vitamin D. In addition, through history, examination, and investigations, the subjects were evaluated according to the pain intensity and duration of the first (active phase) and second stages of labor. Results: The results of the Pearson correlation test indicated a significant relationship between vitamin D and active phase duration (r = 0.64, p = 0.012), second stage duration (r = 0.73, p = 0.001), pain intensity of the active phase (r = 0.61, p = 0.022), and pain intensity of the second stage (r = 0.65, p = 0.026). According to the analysis of variance table, based on vitamin D, there were statistically significant differences between the groups in terms of the active phase duration, second stage duration, pain intensity of the active phase, and that of the second stage of labor (p < 0.05). Conclusions: Low levels of vitamin D may influence the progress of labor and increase the rate of prolonged labor.

A Photoenzymatic Pathway for Gram-Scale Synthesis of 25-Hydroxyvitamin D3.

Vitamin D and its analogues play a crucial role in promoting the well-being of both humans and animals. However, the current synthesis of this vital class of nutrients heavily relies on chemical transformations, which suffer from low step- and atom-efficiency due to lengthy synthetic pathways. To enhance sustainability in the chemical industry, it is necessary to develop alternative synthetic processes. Herein, we present a photoenzymatic approach for synthesizing 25-hydroxyvitamin D3 from 7-dehydrocholesterol. In this sequential synthesis, 7-dehydrocholesterol is initially hydroxylated at the C25 C-H bond, resulting in an 85% conversion to 25-hydroxyl-7-dehydrocholesterol. Subsequently, by employing photo-irradiation using a monochromatic LED ultraviolet light source in a batch reactor and thermal isomerization, 25-hydroxyvitamin D3 is obtained in satisfactory yield. This photoenzymatic process significantly reduces the need for purification steps and allows for gram-scale synthesis of the target product. Our work offers a selective, efficient, and environmentally friendly method for synthesizing 25-OH-vitamin D3, addressing the limitations of current synthetic approaches.

Effect of dietary inclusion of 25-hydroxyvitamin D3 and vitamin E on performance, gut health, oxidative status, and immune response in laying hens infected with coccidiosis.

Vitamin D3 (25-hydroxyvitamin D3 (VD)) and vitamin E (VE) have proven to have immunomodulatory and antioxidant functions along with capacities to improve the reproductive function in chickens. Coccidiosis in laying hens at different stages of growth has been shown to negatively affect performance, immune response, and oxidative status, thus increasing the cost of production. A study was conducted to evaluate the influence of dietary VD or VE on performance, gut health, immune response, and oxidative status of laying hens at peak production. Laying hens (23 wk-of-age, n = 225) were randomly allocated into 5 treatment groups (n = 9 hens/replicate) with 5 replicate groups each: 1) unchallenged control (UC), 2) pair-fed control (PF), 3) challenged control (CC), 4) challenged control top-dressed with 5,000 IU of 25-hydroxyvitamin D3 (VD) per kg of diet, and 5) challenged control top-dressed with 100 IU of DL-α-tocopherol (VE). At 25 wk-of-age, hens grouped in CC, VD, and VE were challenged with mixed Eimeria spp. to induce coccidiosis. VD or VE supplemented hens did not impact bird body weight; however, egg production increased by 10.36% and 13.77%, respectively (P < 0.0001). Furthermore, the gut health of the hens was improved with either VD or VE supplementation, as indicated by lowered gut permeability and intestinal lesion scores (P < 0.05). VE significantly reduced the heterophil count (P = 0.0490) alongside numerically increasing the peripheral CD4+ and CD8+ T cells and monocyte counts (P > 0.05). Both VD or VE increased the TAC at 14 DPI compared to UC (P<0.05). Preliminary findings suggest that dietary VD or VE supplementation has the potential to improve gut health, modulate the immune response, and increase egg production in coccidiosis-infected laying hens.

Identification of South African Plant-Based Bioactive Compounds as Potential Inhibitors against the SARS-CoV-2 Receptor.

The expected progress in SARS-CoV-2 vaccinations, as anticipated in 2020 and 2021, has fallen short, exacerbating global disparities due to a lack of universally recognized "safe and effective" vaccines. This study focuses on extracts of South African medicinal plants, Artemisia annua and Artemisia afra, to identify metabolomic bioactive compounds inhibiting the binding of the SARS-CoV-2 spike protein to ACE2 receptors. The extracts were monitored for cytotoxicity using a resazurin cell viability assay and xCELLigence real-time cell analyzer. Chemical profiling was performed using UPLC-MS/MS, orthogonal projection to latent structures (OPLS), and evaluated using principle component analysis (PCA) models. Identified bioactive compounds were subjected to in vitro SARS-CoV-2 enzyme inhibition assay using standard methods and docked into the spike (S) glycoprotein of SARS-CoV-2 using Schrodinger® suite followed by molecular dynamics simulation studies. Cell viability assays revealed non-toxic effects of extracts on HEK293T cells at lower concentrations. Chemical profiling identified 81 bioactive compounds, with compounds like 6″-O-acetylglycitin, 25-hydroxyvitamin D3-26,23-lactone, and sesaminol glucoside showing promising binding affinity. Molecular dynamics simulations suggested less stable binding, but in vitro studies demonstrated the ability of these compounds to interfere with SARS-CoV-2 spike protein's binding to the human ACE2 receptor. Sesaminol glucoside emerged as the most effective inhibitor against this interaction. This study emphasizes the importance of multiplatform metabolite profiling and chemometrics to understand plant extract composition. This finding is of immense significance in terms of unravelling metabolomics bioactive compounds inhibiting the binding of the SARS-CoV-2 spike protein to ACE2 receptors and holds promise for phytotherapeutics against SARS-CoV-2.

An HPLC-UV Method to Assess Human Plasma 25(OH)D3.

The aim of this study was to validate an HPLC-UV method to assess vitamin D status by determining the linearity and precision of the 25-hydroxyvitamin D3 (25(OH)D3) calibration curve, the limits of detection, quantitation and robustness of the method, and its accuracy. A second stock solution of 25(OH)D3 was prepared (500 ng/mL), and working dilutions (5, 10, 20, 30, 40, and 50 ng/mL) were prepared for a calibration curve. The HPLC equipment had a UV-Vis diode-array detector and utilized an AcclaimTM 120 C18 column (5 µm, 4.6 × 250 mm) with a flow rate of 1.2 mL/min, a column temperature of 30 °C, and the standards and samples were maintained at 4 °C, with an injection volume of 100 µL. Detection of 25(OH)D3 was determined at 265 nm, with a retention time of 4.0 min. The validation was conducted according to the FDA Validation of Analytical Procedures: Guidance for Industry. Vitamin D was extracted from plasma samples using acetonitrile (ACN)-0.1% formic acid (2:1 v/v), and the percentage of recovery was calculated. The proposed method conditions gave excellent linearity (R2 = 0.9989) and the linearity coefficient was R2 > 0.99 for 25(OH)D3. The detection and quantification limits were 1.1703 ng/mL and 3.5462 ng/mL, respectively. Decreasing or increasing the reading temperature by 1 °C decreased the response units (AU) of vitamin D, 25(OH)D3. When the current flow rate decreased by 0.2 mL/min (1.0 mL/min), the retention time increased to 4.913 min, whereas an increase of 0.2 mL/min of the proposed flow rate (1.4 mL/min) decreased the retention time to 3.500 min. The percentage of recovery varied from 92.2% to 97.1%. The proposed method to quantify a vitamin D metabolite (25(OH)D3) in human plasma samples was reliable and validated.

Blood 25-hydroxyvitamin D3 concentration of Japanese Black cattle at two farms with different rearing environments, Kagoshima prefecture, Japan.

Forty-two Japanese Black cattle on two farms in Kagoshima prefecture, Japan were used in this study. The rearing style of farm A was in a dark barn with a large roof to block sunlight (n=21). The rearing style of farm B was grazing, and exposed to direct sunlight (n=21). Blood sampling was performed twice on the same cattle in August 2022 (summer) and February 2023 (winter). As the results, the serum 25(OH)D3 concentrations were significantly lower in cattle of farm A than in cattle of farm B (P<0.01), and were significantly lower in winter season than in summer season (P<0.01). These results showed that there were differences in blood 25(OH)D3 concentrations between the farms or seasons.

Exploring the role of vitamin D in cognitive function: mediation by depression with diabetes modulation in older U.S. adults, a NHANES weighted analysis.

Background: The relationship between vitamin D levels, depressive symptoms, and cognitive function has yet to be definitively understood in the elderly, particularly when considering the impact of chronic diseases. This study focuses on how depression mediates the impact of 25-hydroxyvitamin D3 (25(OH)D3) on cognitive performance in older U.S. adults. Methods: We analyzed data from 2,745 elderly individuals extracted from the NHANES 2011-2014 cycles, applying weighted processing to account for the complex multi-stage sampling design characteristic of NHANES data. Utilizing weighted data for covariate and model selection, we conducted mediation analyses on both the overall population and subgroup data. Significant mediation pathways were validated using a stratified weighted bootstrap approach. For significant subgroup pathways, we explored interactive mechanisms through interactive mediation analysis. Results: Mediation analyses, thoroughly accounting for the impact of chronic conditions, revealed significant pathways in both the weighted overall population and the weighted diabetes subgroup. After 1,000 stratified weighted bootstrap replications, the proportion of mediation effects were 10.6% [0.040, 0.268] and 20.9% [0.075, 0.663], respectively. Interactive mediation analysis for diabetes indicated that the interaction between diabetes and depression was not significant in the direct pathway (estimates = 0.050, p = 0.113) but was significant in the mediation pathway, yielding the largest effect size compared to other covariates (estimates = 0.981, p < 0.001). Conclusion: This study highlights the mediating role of depression in the relationship between vitamin D levels and cognitive function in the elderly, particularly emphasizing diabetes as a key moderator. Our findings suggest targeted interventions addressing both vitamin D sufficiency and depression could significantly benefit cognitive health, especially in diabetic individuals.

A Cross-Sectional Exploratory Study of Cardiovascular Risk Biomarkers in Non-Obese Women with and without Polycystic Ovary Syndrome: Association with Vitamin D.

Vitamin D is proposed to have a protective effect against cardiovascular disease, though the mechanism is unclear. Vitamin D deficiency is common in polycystic ovary syndrome (PCOS), where it is strongly related to obesity, insulin resistance (IR) and risk of cardiovascular disease. To determine if the inherent pathophysiology of PCOS or vitamin D levels are linked to dysregulation of cardiovascular risk proteins (CVRPs), a study in non-obese women with PCOS and without IR was undertaken. Our hypothesis was that the levels of vitamin D3 and its active metabolite would be associated with CVRPs comparably in women with and without PCOS. In women with PCOS (n = 29) and controls (n = 29), 54 CVRPs were determined by Slow Off-rate Modified Aptamer (SOMA)-scan plasma protein measurement and correlated to 25-hydroxyvitamin D3 (25(OH)D3) and the active 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) measured by gold standard isotope-dilution liquid chromatography tandem mass spectrometry. Women with PCOS had comparable IR and systemic inflammation (normal C-reactive protein) to control women, though had higher free androgen index and anti-Mullerian hormone levels. 25(OH)D3 and 1,25(OH)2D3 levels did not differ between groups. Nine CVRPs were higher in PCOS (p < 0.05) (Galectin-9, Brother of CDO, C-motif chemokine 3, Interleukin-18 receptor-1, Thrombopoietin, Interleukin-1 receptor antagonist protein, Programmed cell death 1 ligand-2, Low-affinity immunoglobulin gamma Fc-region receptor II-b and human growth hormone), whilst 45 CVRPs did not differ. 25(OH)D3 correlated with five CVRPs in PCOS and one in controls (p < 0.05). Despite the women with PCOS not exhibiting overt systemic inflammation, 9 of 54 CVRPs were elevated, all relating to inflammation, and 5 of these correlated with 25(OH)D3, suggesting an ongoing underlying inflammatory process in PCOS even in the absence of obesity/IR.

CYP4A22 loss-of-function causes a new type of vitamin D-dependent rickets (VDDR1C).

Vitamin D-dependent rickets (VDDR) is a group of genetic disorders characterized by early-onset rickets due to deficiency of active vitamin D or a failure to respond to activated vitamin D. VDDR is divided into several subtypes according to the corresponding causative genes. Here we described a new type of autosomal dominant VDDR in a Chinese pedigree. The proband and his mother had severe bone malformations, dentin abnormalities, and lower serum 25 hydroxyvitamin D3 (25[OH]D3) and phosphate levels. The proband slightly responded to a high dose of vitamin D3 instead of a daily low dose of vitamin D3. Whole-exome sequencing, bioinformatic analysis, PCR, and Sanger sequencing identified a nonsense mutation in CYP4A22 (c.900delG). The overexpressed wild-type CYP4A22 mainly localized in endoplasmic reticulum and Golgi apparatus, and synthesized 25(OH)D3 in HepG2 cells. The overexpressed CYP4A22 mutant increased the expression of CYP2R1 and produced little 25(OH)D3 with vitamin D3 supplementation, which was reduced by CYP2R1 siRNA treatment. We concluded that CYP4A22 functions as a new kind of 25-hydroxylases for vitamin D3. Loss-of-function mutations in CYP4A22 lead to a new type of VDDR type 1 (VDDR1C). CYP2R1 and CYP4A22 may have some genetic compensation responding to nonsense-mediated mRNA decay effect of each other.

A nonsense mutation in CYP4A22 was found in a Chinese pedigree with vitamin D­dependent rickets and low serum phosphate. CYP4A22 localizes in endoplasmic reticulum and Golgi apparatus, and processes 25-hydroxylase activity in liver cells. CYP4A22 loss-of-function reduces the synthesis of 25(OH)D3 and causes genetic compensation of CYP2R1.

Effects of the Marek's Disease Vaccine on the Performance, Meat Yield, and Incidence of Woody Breast Myopathy in Ross 708 Broilers When Administered Alone or in Conjunction with In ovo and Dietary Supplemental 25-Hydroxycholecalciferol.

The effects of the Marek's disease vaccine (MDV) on the live performance, breast meat yield, and incidence of woody breast myopathy (WBM) of Ross 708 broilers were investigated when administered alone or in conjunction with in ovo and dietary supplemental 25-hydroxycholecalciferol (25OHD3). At 18 d of incubation (doi), four in ovo injection treatments were randomly assigned to live embryonated Ross 708 broiler hatching eggs: (1) non-injected; (2) commercial MDV alone; or MDV containing either (3) 1.2 or (4) 2.4 µg of 25OHD3. An Inovoject multi-egg injector was used to inject a 50 µL solution volume into each egg. The birds were provided a commercial diet that contained 250 IU of cholecalciferol/kg of feed (control) or a commercial diet that was supplemented with an additional 2760 IU of 25OHD3/kg of feed (HyD-diet). In the growout period, 14 male broilers were placed in each of 48 floor pens resulting 6 replicated pens per in ovo x dietary treatment combination. Live performance variable were measured at each dietary phases from 0 to 14, 15 to 28, and 29 to 40 d of age (doa). At 14 and 40 doa, pectoralis major (P. major) and pectoralis minor (P. minor) muscles were determined for one bird within each of the six replicate pens. At 41 doa, WBM incidence was determined. No significant main or interaction effects occurred for WBM among the dietary or in ovo injection treatments. However, in response to in ovo 25OHD3 supplementation, BW and BWG in the 29 to 40 doa period and BWG and FCR in the 0 to 40 doa period improved. In addition, at 40 and 41 doa, breast meat yield increased in response to in ovo and dietary 25OHD3 supplementation. Future research is needed to determine the possible reasons that may have been involved in the aforementioned improvements.

Enhancement of selectivity, 25-hydroxyvitamin D3 level, alkaline phosphatase activity and reproductive performance in gilts and primiparous sows using 14-epimer of 25-hydroxyvitamin D3.

Selecting breed-worthy gilts as sow replacements is essential for continuity of pig production cycle. Though vitamin D3 (VD3) is known to enhance reproductive performance of multiparous sows, there is still a knowledge gap on its impact in developing gilts and primiparous sows. This study was aimed to quantify plasma 25-hydroxyvitamin D3 (25(OH)D3), serum alkaline phosphatase (ALP), and examine the reproductive performance of primiparous sows fed diets supplemented with regular VD3, and its 25(OH)D3 epimers. The study sample comprised 10-week-old replacement gilts (50 % Landrace x 50 % Yorkshire, N = 180) assigned in a randomized complete block design to three treatments [2,000 IU/kg of VD3 (T1), 25 µg/kg of 14­epi-25(OH)D3, half dose (T2), and 50 µg/kg of 25(OH)D3 (T3)] equilibrated to 2,000 IU/kg in base diets. Selections occurred at 22, 27 and 35 weeks of age, respectively. Plasma 25(OH)D3, serum alkaline phosphatase (ALP), bone structure and reproductive performance were analyzed. Dietary treatments influenced carpus (P = 0.023), fore view stance (P = 0.017), infantile vulva (P = 0.014), inverted (P = 0.048), and prominent teat (P < 0.001). Post-partum 25(OH)D3 concentration and ALP activity were elevated by day 25 (P < 0.001). Treatment diets also influenced total born (P < 0.001), born alive (P = 0.048), and still born (P = 0.049). Two factors affect circulating 25(OH)D3 and ALP activity: physiological changes in sows during lactation, and dietary 25(OH)D3 intake. 14­epi-25(OH)D3 is a potent metabolite for improving maturation of reproductive organs in developing gilts. It also reduces still birth in primiparous sows.

Investigating the effects of 25-hydroxyvitamin D3 on clinical outcomes in multiple sclerosis patients: A randomized, double-blind clinical trial- a pilot study.

BACKGROUND: The primary objective of this clinical trial was to assess whether administrating oral calcifediol (25(OH)D3) could enhance the clinical outcomes of patients diagnosed with multiple sclerosis. METHODS: This clinical trial was designed as a randomized, double-blind, two-arm study, with 25 participants receiving daily 50 µg of calcifediol and 25 people receiving daily 50 µg of cholecalciferol. The primary outcomes were serum levels of 25(OH)D3, number of relapses, changes in Kurtzke Expanded Disability Status Scale (EDSS), the 25-foot walk, and cognitive function. RESULTS: At the end of the trial, delta serum concentrations of 25(OH)D3 were 85.32±40.94 ng/ml in the calcifediol group compared to 13.72±11.56 ng/ml in the cholecalciferol group; 84 % of the calcifediol group and none of the cholecalciferol group had circulating 25(OH)D3 concentrations exceeding 70 ng/ml. While both groups showed an overall trend towards improved cognitive function at the end of the study, the calcifediol group exhibited greater improvements in most cognitive tests. However, the trial had no significant beneficial effects on MS relapse, EDSS score, quality of life, or fatigue in either group, the calcifediol or cholecalciferol. CONCLUSIONS: The trial shows that calcifediol is more effective in rapidly increasing 25(OH)D3 levels in MS patients compared to cholecalciferol when administrated at a similar dosage.

Vitamin D Metabolites Before and After Kidney Transplantation in Patients Who Are Anephric.

RATIONALE & OBJECTIVE: Kidneys are vital for vitamin D metabolism, and disruptions in both production and catabolism occur in chronic kidney disease. Although vitamin D activation occurs in numerous tissues, the kidneys are the most relevant source of circulating active vitamin D. This study investigates extrarenal vitamin D activation and the impact of kidney transplantation on vitamin D metabolism in patients who are anephric. STUDY DESIGN: Case series. SETTING & PARTICIPANTS: Adult patients with previous bilateral nephrectomy (anephric) not receiving active vitamin D therapy evaluated at the time of (N=38) and 1 year after (n=25) kidney transplantation. ANALYTICAL APPROACH: Chromatography with tandem mass spectrometry was used to measure vitamin D metabolites. Activity of CYP24A1 [24,25(OH)2D/25(OH)D] and CYP27B1 [1α,25(OH)2D/25(OH)D] is expressed as metabolic ratios. Differences between time points were evaluated by paired t-test or Wilcoxon matched-pairs signed-rank test. RESULTS: At time of transplantation, 1α,25(OH)2D was detectable in all patients (4-36pg/mL). There was a linear relationship between 25(OH)D and 1α,25(OH)2D levels (r=0.58, P<0.001), with 25(OH)D explaining 34% of the variation in 1α,25(OH)2D levels. There were no associations between 1α,25(OH)2D and biointact parathyroid hormone (PTH) or fibroblast growth factor 23 (FGF-23). One year after transplantation, 1α,25(OH)2D levels recovered (+205%), and CYP27B1 activity increased (+352%). Measures of vitamin D catabolism, 24,25(OH)2D and CYP24A1 activity increased 3- to 5-fold. Also, at 12 months after transplantation, 1α,25(OH)2D was positively correlated with PTH (ρ=0.603, P=0.04) but not with levels of 25(OH)D or FGF-23. LIMITATIONS: Retrospective, observational study design with a small cohort size. CONCLUSIONS: Low-normal levels of 1α,25(OH)2D was demonstrated in anephric patients, indicating production outside the kidneys. This extrarenal CYP27B1 activity may be more substrate driven than hormonally regulated. Kidney transplantation seems to restore kidney CYP27B1 and CYP24A1 activity, as evaluated by vitamin D metabolic ratios, resulting in both increased vitamin D production and catabolism. These findings may have implications for vitamin D supplementation strategies in the setting of kidney failure and transplantation. PLAIN-LANGUAGE SUMMARY: Vitamin D activation occurs in multiple tissues, but the kidneys are considered the only relevant source of circulating levels. This study investigates vitamin D activation outside the kidneys by measuring vitamin D metabolites in 38 patients without kidneys. Active vitamin D was detectable in all patients, indicating production outside of the kidneys. There was a strong relationship between active and precursor vitamin D levels, but no association with mineral metabolism hormones, indicating that vitamin D production was more substrate dependent than hormonally regulated. One year after kidney transplantation, active vitamin D levels increased 2-fold and breakdown products increased 3-fold, indicating that production and degradation of the hormone recovers after kidney transplantation. These findings are relevant for future research into vitamin D supplementation in kidney failure.

Investigating the comparative effect of vitamin D level with the type of complications in Henoch Schönlein purpura and Kawasaki disease.

INTRODUCTION AND OBJECTIVES: Henoch Schönlein purpura (HSP) and Kawasaki disease (KD) are two main inflammatory diseases among childhood vasculitis. Considering the anti-inflammatory effects of 25-hydroxyvitamin D3, we decided to investigate the association of serum 25-hydroxy vitamin D3 level with the type and severity of these conditions. MATERIALS AND METHODS: The present study was performed as a historical cohort of 254 affected children with KD and HSP vasculitis. The required data were extracted, using a researcher-made questionnaire from patients' electronic file, and then they were analyzed after collecting information of the patients. RESULTS: In HSP group, 54% of participants were boys. Similarly, in KD group, boys were more affected than girls. The comparative 25-hydroxyvitamin vitamin D3 level in HSP patients with and without renal involvement (P=0.02), hematuria (P=0.14), and in two groups with and without heart disease, and also with and without coronary artery dilatation in KD patients (P<0.001) were significant. DISCUSSION AND CONCLUSIONS: The findings showed that insufficient level of vitamin D3 were significantly associated with the exacerbation of complications of both diseases, and therefore it seems that vitamin D deficiency can be an effective predictive factor of severity in HSP and KD patients.

Relationship between vitamin D levels and pediatric celiac disease: a systematic review and meta-analysis.

BACKGROUND: The relationship between Vitamin D levels and pediatric celiac disease (CD) remains controversial. In this study, we conducted a systematic review and meta-analysis to examine the relationship between Vitamin D and pediatric CD. METHODS: We screened relevant studies from PubMed, EMBASE, and Web of Science published in English from January 1, 2000, to August 1, 2023. The included studies were assessed according to the STROBE checklist. Heterogeneity was quantified by Cochran's Q test and the I2 statistic. Publication bias was estimated by Begg's test and Egger's test. Meta-regression was used to detect potential sources of heterogeneity. RESULTS: A total of 26 studies were included in the meta-analysis. Nineteen articles compared 25(OH)D3 levels between CD patients and control groups, average 25-hydroxyvitamin D3 [25(OH)D3 or calcidiol], and 1,25-dihydroxyvitamin D3 [1,25(OH)2D3 or calcitriol] levels, as the main forms of Vitamin D, there was a significant difference in CD patients and healthy controls (weighted mean difference (WMD) = - 5.77, 95% confidence interval (CI) = [- 10.86, - 0.69] nmol/L). Meanwhile, eleven articles reported the numbers of patients and controls with Vitamin D deficiency, there was a significant difference in the incidence of 25(OH)D3 deficiency between CD patients and healthy controls (odds ratio 2.20, 95% CI= [1.19, 4.08]). Nine articles reported changes in 25(OH)D3 levels before and after administering a GFD in patients with CD, the result of this study revealed the increase of 25(OH)D3 levels in CD patients after a gluten-free diet (GFD) (WMD = - 6.74, 95% CI = [- 9.78, - 3.70] nmol/L). CONCLUSIONS: Vitamin D levels in pediatric CD patients were lower than in healthy controls, and 25(OH)D3 deficiency was more prevalent in CD patients. We found that 25(OH)D3 levels were elevated in CD patients after GFD, which is consistent with previous research. Further well-designed, longitudinal, prospective cohort studies focusing on the role of Vitamin D in the pathogenesis of CD are therefore needed.

Oleanolic acid exerts bone anabolic effects via activation of osteoblastic 25-hydroxyvitamin D 1-alpha hydroxylase.

Oleanolic acid (OA) is previously shown to exert bone protective effects in aged animals. However, its role in regulating osteoblastic vitamin D bioactivation, which is one of major causes of age-related bone loss, remains unclear. Our results revealed that treatment of OA significantly increased skeletal CYP27B1 expression and circulating 1,25(OH)2D3 in ovariectomized mice (p <0.01). Moreover, OA upregulated CYP27B1 protein expression and activity, as well as the vitamin D-responsive bone markers alkaline phosphatase (ALP) activity and osteopontin (OPN) protein expression, in human osteoblast-like MG-63 cells (p<0.05). CYP27B1 expression increased along with the osteoblastic differentiation of human bone marrow derived mesenchymal stem cells (hMSCs). CYP27B1 expression and cellular 1,25(OH)2D3 production were further potentiated by OA in cells at mature osteogenic stages. Notably, our study suggested that the osteogenic actions of OA were CYP27B1 dependent. In summary, the bone protective effects of OA were associated with the induction of CYP27B1 activity and expression in bone tissues and osteoblastic lineages. Hence, OA might be a potential approach for management of age-related bone loss.

Dietary 25 Hydroxyvitamin D3 Improved Serum Concentration Level and Alkaline Phosphatase Activity during Lactation but Had Meager Impact on Post-Farrowing Reproductive Performance in Sows.

Dietary 25 hydroxyvitamin D3 (25(OH)D3) promotes serum 25(OH)D3 concentration and alkaline phosphatase activity (ALP); however, post-farrowing reproductive performance of lactating sows fed with 14-epimer of 25(OH)D3 is uncertain. This study investigated post-farrowing reproductive performance, serum ALP activity, and serum 25(OH)D3 concentration in sows fed VD3, 25(OH)D3, or 14-epi 25(OH)D3. Weaned sows (n = 203) in parities 2 and 3 were blocked weekly and treated with 2000 IU/kg VD3 (T1), 25 µg/kg 25(OH)D3:14-epi 25(OH)D3 (T2), or 50 µg/kg 25(OH)D3 (T3) diets, all equilibrated to 2000 IU/kg as fed. Sow performance, treatment, and sampling period effects were analyzed. Environmental conditions were analyzed as covariates. The number of piglets weaned (p = 0.029), pre-weaning mortality (p = 0.029), sampling period (p < 0.001), and treatment and period interaction (p = 0.028) differed significantly. There was an increase in 25(OH)D3 during lactation due to physiological demands for milk calcium and milk production. Supplementing twice the concentration of 25(OH)D3 compared to its epimer, 25(OH)D3:14-epi 25(OH)D3, had no significant effect on the post-farrowing reproductive performance of lactating sows. The effect of 25(OH)D3 on post-farrowing reproductive performance and ALP activity in sows was influenced by metabolic demand for calcium due to physiological changes during lactation as well as epimer conformation.

Evolution and impact of Standard Reference Materials (SRMs) for determining vitamin D metabolites.

The National Institute of Standards and Technology (NIST), in collaboration with the National Institutes of Health, Office of Dietary Supplements (NIH ODS), introduced the first Standard Reference Material® (SRM) for determining vitamin D metabolites in 2009 motivated by significant concerns about the comparability and accuracy of different assays to assess vitamin D status. After 14 years, a suite of five serum matrix SRMs and three calibration solution SRMs are available. Values were also assigned for vitamin D metabolites in five additional SRMs intended primarily to support measurements of other clinical diagnostic markers. Both the SRMs and the certification approach have evolved from significant exogenous serum content to primarily endogenous content and from value assignment by combining the results of multiple analytical methods to the use of measurements exclusively from reference measurement procedures (RMPs). The impact of the availability of these SRMs can be assessed by both the distribution information (sales) and by reports in the scientific literature describing their use for method validation, quality control, and research. In this review, we describe the development of these SRMs, the evolution in design and value assignment, the expansion of information reported, and SRM use in validating analytical methods and providing quality assurance within the vitamin D measurement community.