Vitamin D3 Metabolites Research Articles

Machine learning‐based phenotypic screening for postmitotic growth inducers uncover vitamin D3 metabolites as small molecule ribosome agonists

ObjectivesTo restore tissue growth without increasing the risk for cancer during aging, there is a need to identify small molecule drugs that can increase cell growth without increasing cell proliferation. While there have been numerous high‐throughput drug screens for cell proliferation, there have been few screens for post‐mitotic anabolic growth.Materials and MethodsA machine learning (ML)‐based phenotypic screening strategy was used to discover metabolites that boost muscle growth. Western blot, qRT‐PCR and immunofluorescence staining were used to evaluate myotube hypertrophy/maturation or protein synthesis. Mass spectrometry (MS)‐based thermal proteome profiling‐temperature range (TPP‐TR) technology was used to identify the protein targets that bind the metabolites. Ribo‐MEGA size exclusion chromatography (SEC) analysis was used to verify whether the ribosome proteins bound to calcitriol.ResultsWe discovered both the inactive cholecalciferol and the bioactive calcitriol are amongst the top hits that boost post‐mitotic growth. A large number of ribosomal proteins' melting curves were affected by calcitriol treatment, suggesting that calcitriol binds to the ribosome complex directly. Purified ribosomes directly bound to pure calcitriol. Moreover, we found that calcitriol could increase myosin heavy chain (MHC) protein translation and overall nascent protein synthesis in a cycloheximide‐sensitive manner, indicating that calcitriol can directly bind and enhance ribosomal activity to boost muscle growth.ConclusionThrough the combined strategy of ML‐based phenotypic screening and MS‐based omics, we have fortuitously discovered a new class of metabolite small molecules that can directly activate ribosomes to promote post‐mitotic growth.

Combined Maternal and Post-Hatch Dietary Supplementation of 25-Hydroxycholecalciferol Alters Early Post-Hatch Broiler Chicken Duodenal Macrophage and Crypt Cell Populations and Their Mitotic Activity.

The previous work has demonstrated that maternal supplementation of the circulating metabolite of vitamin D3 (D3), 25-hydroxycholecalciferol (25OHD3), enhances the immunocompetence of broiler chick offspring. In post-hatch broiler diets, 25OHD3 has been shown to affect intestinal morphology and improve the immune status of broilers. An experiment with a 2 × 2 factorial treatment arrangement was conducted to assess the effects of combining maternal (MDIET) and post-hatch (PDIET) dietary 25OHD3 inclusion on duodenal crypt and macrophage cell populations and mitotic activity in young broiler chickens. All diets were formulated to provide 5,000 IU of vitamin D. Broiler breeder hens were offered 1 of 2 MDIET: 5,000 IU D3 per kg of feed (MCTL) or 2,240 IU of D3 + 2,760 IU of 25OHD3 per kg of feed (M25OHD3) from week 25 to 41. Male broiler offspring (n = 480) hatched from eggs collected during week 41 of breeding age were allotted in raised floor pens (4 birds per pen from day 0 to 7 and individually allotted from day 8 to 21). Chicks were fed 1 of 2 PDIET (starter day 0 to 21): 5,000 IU D3 per kg of feed (PCTL) or 2,240 IU D3 + 2,760 IU 25OHD3 (P25OHD3). DUO samples (n = 12 birds per treatment per day) were collected on days 3, 6, 9, 12, 15, 18, and 21 for cryohistological and immunofluorescence analysis to facilitate the enumeration of the total macrophages, CD80+ macrophages (pro-inflammatory macrophages), and mitotically active cells (BrdU+) to calculate the proportion of proliferating cells (PPC) per duodenal crypt. Bird age impacted crypt PPC with the greatest PPC per duodenal crypt observed on days 3 and 9, and the lowest PPC per crypt was observed on day 21 (P < 0.0001). Broilers from the M25OHD3:PCTL treatment had a greater PPC (P =.002) than birds from the MCTL:PCTL treatment at day 3. An interaction among MDIET and PDIET was observed for proliferating macrophages at day 21 (P = 0.029) where M25OHD3:P25OHD3 birds had more proliferating macrophages than M25OHD3:PCTL-fed birds. These results indicate that combined MDIET and PDIET 25OHD3 supplementation may alter early post-hatch duodenal development and innate immunity.

Synthesis of Deuterium-Labeled Vitamin D Metabolites as Internal Standards for LC-MS Analysis.

Blood levels of the vitamin D3 (D3) metabolites 25-hydroxyvitamin D3 (25(OH)D3), 24R,25-dihydroxyvitamin D3, and 1α,25-dihydroxyvitamin D3 (1,25(OH)2D3) are recognized indicators for the diagnosis of bone metabolism-related diseases, D3 deficiency-related diseases, and hypercalcemia, and are generally measured by liquid-chromatography tandem mass spectrometry (LC-MS/MS) using an isotope dilution method. However, other D3 metabolites, such as 20-hydroxyvitamin D3 and lactone D3, also show interesting biological activities and stable isotope-labeled derivatives are required for LC-MS/MS analysis of their concentrations in serum. Here, we describe a versatile synthesis of deuterium-labeled D3 metabolites using A-ring synthons containing three deuterium atoms. Deuterium-labeled 25(OH)D3 (2), 25(OH)D3-23,26-lactone (6), and 1,25(OH)2D3-23,26-lactone (7) were synthesized, and successfully applied as internal standards for the measurement of these compounds in pooled human serum. This is the first quantification of 1,25(OH)2D3-23,26-lactone (7) in human serum.

Vitamin D Metabolites in Nonmetastatic High-Risk Prostate Cancer Patients with and without Zoledronic Acid Treatment after Prostatectomy.

Simple SummaryRecent research on prostate cancer and vitamin D is controversial. We measured three vitamin D3 metabolites in 32 selected prostate cancer patients after surgery at four time points over four years. Within a large European study, half of the patients were prophylactically treated with zoledronic acid (ZA); the others received a placebo. After the study start, all the patients daily took calcium and vitamin D3. The development of metastasis was not affected by ZA treatment. While two vitamin D metabolites had higher values after the study’s start, with constant follow-up values, the 1,25(OH)2-vitamin D3 concentrations remained unchanged. The latter form was the only metabolite that was higher in the patients with metastasis as compared to those without bone metastasis. This result is surprising. However, it is too premature to discuss possible prognostic value yet. Our results should be confirmed in larger cohorts.There are limited and discrepant data on prostate cancer (PCa) and vitamin D. We investigated changes in three vitamin D3 metabolites in PCa patients after prostatectomy with zoledronic acid (ZA) treatment regarding their metastasis statuses over four years. In 32 patients from the ZEUS trial, 25(OH)D3, 24,25(OH)2D3, and 1,25(OH)2D3 were measured with liquid chromatography coupled with tandem mass spectrometry at four time points. All the patients received daily calcium and vitamin D3. Bone metastases were detected in 7 of the 17 ZA-treated patients and in 5 of the 15 controls (without ZA), without differences between the groups (p = 0.725). While 25(OH)D3 and 24,25(OH)2D3 increased significantly after the study’s start, with following constant values, the 1,25(OH)2D3 concentrations remained unchanged. ZA treatment did not change the levels of the three metabolites. 25(OH)D3 and 24,25(OH)2D3 were not associated with the development of bone metastases. In contrast, 1,25(OH)2D3 was also higher in patients with bone metastasis before the study’s start. Thus, in high-risk PCa patients after prostatectomy, 25(OH)D3, 24,25(OH)2D3, and 1,25(OH)2D3 were not affected by supportive ZA treatment or by the development of metastasis over four years, with the exception of 1,25(OH)2D3, which was constantly higher in metastatic patients. There might be potential prognostic value if the results can be confirmed.

Vitamin D May Protect against Breast Cancer through the Regulation of Long Noncoding RNAs by VDR Signaling.

Dietary vitamin D3 has attracted wide interest as a natural compound for breast cancer prevention and therapy, supported by in vitro and animal studies. The exact mechanism of such action of vitamin D3 is unknown and may include several independent or partly dependent pathways. The active metabolite of vitamin D3, 1α,25-dihydroxyvitamin D3 (1,25(OH)2D, calcitriol), binds to the vitamin D receptor (VDR) and induces its translocation to the nucleus, where it transactivates a myriad of genes. Vitamin D3 is involved in the maintenance of a normal epigenetic profile whose disturbance may contribute to breast cancer. In general, the protective effect of vitamin D3 against breast cancer is underlined by inhibition of proliferation and migration, stimulation of differentiation and apoptosis, and inhibition of epithelial/mesenchymal transition in breast cells. Vitamin D3 may also inhibit the transformation of normal mammary progenitors into breast cancer stem cells that initiate and sustain the growth of breast tumors. As long noncoding RNAs (lncRNAs) play an important role in breast cancer pathogenesis, and the specific mechanisms underlying this role are poorly understood, we provided several arguments that vitamin D3/VDR may induce protective effects in breast cancer through modulation of lncRNAs that are important for breast cancer pathogenesis. The main lncRNAs candidates to mediate the protective effect of vitamin D3 in breast cancer are lncBCAS1-4_1, AFAP1 antisense RNA 1 (AFAP1-AS1), metastasis-associated lung adenocarcinoma transcript 1 (MALAT1), long intergenic non-protein-coding RNA 511 (LINC00511), LINC00346, small nucleolar RNA host gene 6 (SNHG6), and SNHG16, but there is a rationale to explore several other lncRNAs.

Physiological levels of 25-hydroxyvitamin D3 induce a suppressive CD4+ T cell phenotype not reflected in the epigenetic landscape.

1,25-dihydroxyvitamin D3 (1,25(OH)2 D3 ), the active metabolite of vitamin D3 has a strong impact on the differentiation and function of immune cells. Here we analysed the influence of its precursor 25-hydroxyvitamin D3 (25(OH)D3 ) on the differentiation of human CD4+ T cells applying physiological concentrations in vitro. Our data show that 25(OH)D3 is converted to its active form 1,25(OH)2 D3 by T cells, which in turn supports FOXP3, CD25 and CTLA-4 expression and inhibits IFN-γ production. These changes were not reflected in the demethylation of the respective promoters. Furthermore, we investigated the impact of vitamin D3 metabolites under induced Treg (iTreg) polarization conditions using TGF-β. Surprisingly, no additive effect but a decreased percentage of FOXP3 expressing cells was observed. However, the combination of 25(OH)D3 or 1,25(OH)2 D3 together with TGF-β further upregulated CD25 and CTLA-4 and significantly increased soluble CTLA-4 and IL-10 secretion whereas IFN-γ expression of iTreg was decreased. Our data suggest that physiological levels of 25(OH)D3 act as potent modulator of human CD4+ T cells and autocrine or paracrine production of 1,25(OH)2 D3 by T cells might be crucial for the local regulation of an adaptive immune response. However, since no epigenetic changes are detected by 25(OH)D3 a rather transient phenotype is induced.

Effects of feeding different doses of 25-hydroxyvitamin D3 on the growth performance, blood minerals, antioxidant status and immunoglobulin of preweaning calves

The objective of this trial was to investigate the effects of feeding different doses of 25-hydroxyvitamin D3 (25(OH)D3) on the growth performance, blood minerals, vitamin D3 metabolites, antioxidant capacity and immunoglobulin of pre-weaned calves. In this experiment, eighteen Holstein calves (3.5 ± 1.24 days, average body weight: 40.68 ± 1.21 kg) were randomly assigned to 1 of 3 treatments (6 calves per group): the control group (0 IU 25(OH)D3 per calf per day), low-dose group (6000 IU 25(OH)D3 per calf per day) and high-dose group (12,000 IU 25(OH)D3 per calf per day). The 25(OH)D3 was mixed into the milk and offered to the calves. Calves fed 25(OH)D3 showed a linear increase in ADG (P = 0.013) and feed efficiency (P = 0.039) from 1 to 8 weeks, the withers height showed an improvement (P < 0.05) at 56 d. The plasma total calcium level tended to increase (P = 0.074) at 28 d and linearly increased (P = 0.012) at 56 d, and plasma 25(OH)D3 in calves linearly increased (P < 0.001) by feeding 25(OH)D3. The plasma total phosphorus content linearly increased (P = 0.003) at 56 d, but there was no difference in plasma total magnesium content by increasing feeding 25(OH)D3. Plasma growth hormone (P = 0.276) and insulin-like growth factor Ⅰ (P = 0.117) were not affected by treatment at 28 d, but growth hormone tended to increase (P = 0.058) and insulin-like growth factor Ⅰ linearly increased (P = 0.018) by increasing feeding 25(OH)D3 at 56 d. Plasma catalase (P < 0.05) and superoxide dismutase (P = 0.010) contents linearly increased by increasing feeding 25(OH)D3. Additionally, increasing 25(OH)D3 supplementation linearly increased (P < 0.05) the plasma immunoglobulin G concentration. In conclusion, the results indicated that feeding 25(OH)D3 (especially high dose of 25(OH)D3) could effectively improve growth performance, plasma minerals and hormones concentration and enhance the antioxidant capacity and immunoglobulin of calves. Feeding 25(OH)D3 is expected to be an effective means of promoting growth and maintaining the health of calves before weaning.

Vitamin D status is heritable and under environment-dependent selection in the wild.

Vitamin D has a well‐established role in skeletal health and is increasingly linked to chronic disease and mortality in humans and companion animals. Despite the clear significance of vitamin D for health and obvious implications for fitness under natural conditions, no longitudinal study has tested whether the circulating concentration of vitamin D is under natural selection in the wild. Here, we show that concentrations of dietary‐derived vitamin D2 and endogenously produced vitamin D3 metabolites are heritable and largely polygenic in a wild population of Soay sheep (Ovis aries). Vitamin D2 status was positively associated with female adult survival, and vitamin D3 status predicted female fecundity in particular, good environment years when sheep density and competition for resources was low. Our study provides evidence that vitamin D status has the potential to respond to selection, and also provides new insights into how vitamin D metabolism is associated with fitness in the wild.

Role of cytochrome P450 for vitamin D metabolisms in patients with neurodegenerative disorders

IntroductionWe previously reported lower serum 25-hydroxyvitamin D concentrations in patients with Alzheimer’s disease (AD), Parkinson’s disease (PD) and Multiple system atrophy (MSA) compared to healthy controls (HC), whereas 1,25-di-hydroxyvitamin D levels were solely lower in MSA patients. We investigate serum concentrations of P450 involved in Vitamin D(VD) hydroxylation to clarify the responsible hydroxylase for the low serum concentrations of VD metabolites. MethodsA total of 79 individuals were enrolled including 20 HC, 20 AD, 19 PD and 20 MSA patients. The serum concentrations of P450 involved in VD hydroxylation were assayed by ELISA. The data were analyzed by the nonparametric Kruskal-Wallis test between groups. ResultsThough CYP2R1 and CYP27A1 mediate 25-hydroxylation for VD, CYP2R1 is the main hydroxylase, and CYP27A1 is also involved in VD synthesis. CYP2R1 concentrations showed no differences among groups, while lower CYP27A1 concentrations were found in PD (p < 0.05) and MSA (p < 0.005) compared to HC and differences between AD and MSA (p < 0.05), however no differences between PD and MSA. CYP27B1 is the main 1α-hydroxylase for 25-hydroxyvitamin D and showed differences between HC and PD (p < 0.05), between HC and MSA (p < 0.005) and between PD and MSA (p = 0.055). CYP24A1, which inactivate 1,25-di-hydroxyvitamin D, showed no differences among groups. ConclusionsCYP27A1 might affect VD synthesis and cause low 25-hydroxyvitamin D levels in AD, PD and MSA patients. Low 1,25-di-hydroxyvitamin D levels in MSA patients might be caused by impaired feedback mediated by CYP27B1.

The role of vitamin D deficiency in antituberculous protection

BACKGROUND. The main task of modern phthysiology is a comprehensive search for ways to optimize the etiotropic and the pathogenetic treatment of tuberculosis (TB). The search for improved treatment in addition to etiotropic antimicrobial therapy lies in the plane of improving pathogenetic therapy. Analysis of the available scientific sources suggests that the efficacy of TB treatment can be improved by adding vitamin D to the pathogenetic treatment, as vitamin D metabolites support the innate immune response to Mycobacterium tuberculosis.&#x0D; OBJECTIVE. To determine the role of vitamin D in the immunopathogenesis of the inflammatory response in pulmonary TB and to assess the prospects of its impact on improving the effectiveness of treatment by analyzing information from available scientific sources on this topic.&#x0D; MATERIALS AND METHODS. The study was performed for the period December 2020 – August 2021. The search was conducted by&#x0D; Keywords:&#x0D; pulmonary tuberculosis, vitamin D, mechanism of action, pathogenesis, treatment. Access to various full-text and abstract databases was used as the main source of research.&#x0D; RESULTS AND DISCUSSION. A large number of studies conducted so far prove the link between vitamin D deficiency and the occurrence of pulmonary TB. Vitamin D receptors have been found to be present on various surfaces of immune cells, including T and B cells, indicating that they need vitamin D to perform cellular functions. Vitamin D has been shown to increase the phagocytic activity of macrophages, and that monocytes incubated with cholecalciferol (vitamin D3) metabolites induce anti-TB activity. A number of studies have shown that vitamin D increases the body’s production of the antimicrobial/antimycobacterial peptide LL-37, a member of the cathelicidin petelide family. Therefore, the narrowly analyzed analysis according to the literature suggests that in the conditions of full vitamin D status of the human body the course of TB will be favorable, and in case of vitamin D deficiency – which is primarily associated with genetic polymorphisms, the course of TB may be unfavorable.&#x0D; CONCLUSIONS. Vitamin D functionates as one of the activators of macrophages and plays a role in the immune defense of the human body against mycobacterial TB. The inclusion of vitamin D in the program of complex treatment of TB infection is promising, as it enhances the production of antimicrobial/antimycobacterial peptide LL-37. It can be used as one of the components of TB prevention in children.

Improving the treatment of patients with osteoporosis in outpatient settings

Examined 140 women in the postmenopausal period. The phenomena of osteoporosis were revealed in all patients with a decrease of the T index of bone density by ultrasonic densitometry of the calcaneus. Decrease in serum 25-hydroxy-cholecalciferol levels. Increased markers of bone resorption of osteocalcin in the blood and disoxypyridinoline (DPID) in the urine. As a result of treatment, there was a normalization of the level of 25-hydroxycholecalciferol and a decrease оf osteocalcin in the blood and DPID in the urine in patients of the first group who received basic therapy, a combined preparation containing 1250 mg of calcium carbonate and 400 IU of vitamin D3 in one tablet. Patients of the second group, who received, in addition to basic therapy, alendronate, showed a normalization of the level of the metabolite of vitamin D3, as well as a decrease to normal levels of osteocalcin in the blood and DPID in the urine.

The Atrophic Effect of 1,25(OH)2 Vitamin D3 (Calcitriol) on C2C12 Myotubes Depends on Oxidative Stress.

Dysfunctional mitochondrial metabolism has been linked to skeletal muscle loss in several physio-pathological states. Although it has been reported that vitamin D (VD) supports cellular redox homeostasis by maintaining normal mitochondrial functions, and VD deficiency often occurs in conditions associated with skeletal muscle loss, the efficacy of VD supplementation to overcome muscle wasting is debated. Investigations on the direct effects of VD metabolites on skeletal muscle using C2C12 myotubes have revealed an unexpected pro-atrophic activity of calcitriol (1,25VD), while its upstream metabolites cholecalciferol (VD3) and calcidiol (25VD) have anti-atrophic effects. Here, we investigated if the atrophic effects of 1,25VD on myotubes depend on its activity on mitochondrial metabolism. The impact of 1,25VD and its upstream metabolites VD3 and 25VD on mitochondria dynamics and the activity of C2C12 myotubes was evaluated by measuring mitochondrial content, architecture, metabolism, and reactive oxygen species (ROS) production. We found that 1,25VD induces atrophy through protein kinase C (PKC)-mediated ROS production, mainly of extramitochondrial origin. Consistent with this, cotreatment with the antioxidant N-acetylcysteine (NAC), but not with the mitochondria-specific antioxidant mitoTEMPO, was sufficient to blunt the atrophic activity of 1,25VD. In contrast, VD3 and 25VD have antioxidant properties, suggesting that the efficacy of VD supplementation might result from the balance between atrophic pro-oxidant (1,25VD) and protective antioxidant (VD3 and 25VD) metabolites.

Potential of a rumen bolus containing 1,25-dihydroxyvitamin D3 glycosides for the prevention of hypocalcaemia in primiparous and multiparous dairy cows

Periparturient hypocalcaemia is a widespread metabolic disorder in dairy cows. Clinical and subclinical cases occur primarily in multiparous (Multi) cows, but subclinical cases have also been reported in primiparous (Primi) cows. A preventive strategy was investigated by administering the physiologically active vitamin D3 metabolite, 1,25-dihydroxyvitamin D3 (1,25-dihydroxycholecalciferol, 1,25(OH)2D3) as a rumen bolus. The bolus contained tablets of 1,25(OH)2D3 glycoside extract from Solanum glaucophyllum (SGE), releasing SGE over several days. The aim was to study the effect of a bolus containing 0 (C) or 500 µg (SGE) of 1,25(OH)2D3 on 1,25(OH)2D3 and mineral status in periparturient cows up to three weeks into lactation and on colostrum, milk and calves’ blood mineral contents. The bolus was administered three to four days prior to expected calving to Primi and Multi cows fed a herbage-based diet (dietary cation-anion difference of +522 mEq/kg DM). One C or SGE bolus was applied to 12 Primi and 12 Multi cows. Blood was regularly sampled (and selected a posteriori for antepartum samples) in regard to the actual calving day (d0), immediately prior to bolus application and at day −2, 0.5, 1, 1.5, 2, 4, 8, 11, 15, 18 and 22. Additional samples included urine (at bolus application, d0.5 and d2), colostrum, milk samples (weekly) and calves’ blood (d2). Blood serum 1,25(OH)2D3 increased between d0.5 and d2 in Primi-SGE, but remained unchanged in Primi-C, as did parathyroid hormone (PTH) and Ca in all Primi. Urinary Ca of Primi-SGE was increased on d2, indicating regulation of Ca excess. Three Multi-C cows with confirmed clinical hypocalcaemia needed treatment and thus were excluded from the dataset and replaced. Blood serum 1,25(OH)2D3 and PTH increased while Ca dropped by 40% between d0.5 and d2 in Multi-C, whereas 1,25(OH)2D3, Ca and PTH remained unchanged in Multi-SGE. Blood serum carboxyterminal telopeptide of type I collagen was higher in Primi than in Multi and increased with time, except in Primi-C. Mineral contents in colostrum, milk and blood serum of calves were not influenced to a relevant degree. In conclusion, Primi-C did not, in contrast to Multi-C, develop subclinical hypocalcaemia (<2.0 mmol Ca/l). Prevention of hypocalcaemia with one SGE bolus applied three to four days prior to expected calving was successful in maintaining blood Ca within normal range in Multi over the critical first two days and up to the first three weeks of lactation, without any observed detrimental effects on cows or calves.

Pharmacokinetics of 1,25-dihydroxyvitamin D3 glycosides from Solanum glaucophyllum extract given in a rumen bolus on blood mineral profiles in dry pregnant dairy cows

Providing tablets of 1,25-dihydroxyvitamin D3 (1,25(OH)2D3), the biologically active metabolite of vitamin D3, in a rumen bolus may be used as prevention for periparturient hypocalcemia in dairy cows. This study investigated the pharmacokinetics of 1,25(OH)2D3 glycosides extracted from Solanum glaucophyllum (SGE) on blood serum 1,25(OH)2D3, Ca, P and Mg response in dry pregnant dairy cows. Boluses contained tablets of SGE which differed in their release properties (rapid release, slow release and combination) and galenics (200 μg uncoated, 300 μg and 500 μg uncoated or coated, 2 × 500 μg uncoated). Nineteen blood samples were collected from 29 cows between 96 h before and 336 h after bolus administration. Blood serum 1,25(OH)2D3, Ca and P increased between 12 h and 120 h, 12 h and 264 h and 24 h and 264 h, respectively. Highest values were reached at 30 h, 72 h and 120 h for 1,25(OH)2D3, Ca and P, respectively. Baseline values were then reached at 216 h for 1,25(OH)2D3 and 336 h for Ca and P. Concentration of Mg decreased between 24 h and 216 h, before reaching values comparable to baseline at 264 h. Highest Ca values were obtained with the combined rapid and slow release properties (500 μg) and there was no effect from coating on pharmacokinetics. In conclusion, the antepartum oral SGE bolus administration may be suitable for the prevention of periparturient hypocalcemia.

VITAMIN D STATUS OF INDOOR-HOUSED HOFFMANN'S TWO-TOED SLOTHS (CHOLOEPUS HOFFMANNI): A PILOT STUDY.

Disorders of calcium homeostasis have been reported with some frequency in two-toed sloths, yet little investigation has been performed on vitamin D and mineral metabolism in these species. This study evaluates biomarkers involved in vitamin D and calcium metabolism in a group of nine managed Hoffmann's two-toed sloths (Choloepus hoffmanni), correlated with diet analysis. Serum was analyzed for both vitamin D2 and D3 metabolites, minerals (calcium [Ca], phosphorus [P], and magnesium [Mg]), parathyroid hormone (PTH), and ionized calcium (iCa). The diet was analyzed for proximate nutrients, minerals and vitamins D2 and D3, and feed intake was estimated. Average values reported for D3 metabolites, including 25(OH)D3, 1,25(OH)2D3, and 24,25(OH)2D3, were 25.1 ng/ml, 52.23 pg/ml, and 7.65 ng/ml, respectively. Average PTH was 0.22 pmol/L while average iCa was 1.46 mmol/L. Values reported for Ca, P, Mg were within expected ranges. Dietary concentration of D3 was 6.7 ng/g and the average daily intake per sloth was 113.7 IU/kg body weight. No detectable levels of vitamin D2 metabolites 25(OH)D2, 1,25(OH)2D2, or 24,25(OH)2D2 were found in the diet or serum. These data will serve as a starting point for future investigations into the vitamin D metabolism and calcium homeostasis of two-toed sloths to improve the health in managed settings.

Controlled lipid β-oxidation and carnitine biosynthesis by a vitamin D metabolite

Lactone-vitamin D3 is a major metabolite of vitamin D3, a lipophilic vitamin biosynthesized in numerous life forms by sunlight exposure. Although lactone-vitamin D3 was discovered 40 years ago, its biological role remains largely unknown. Chemical biological analysis of its photoaffinity probe identified the hydroxyacyl-CoA dehydrogenase trifunctional multienzyme complex subunit alpha (HADHA), a mitochondrial enzyme that catalyzes β-oxidation of long-chain fatty acids, as its selective binding protein. Intriguingly, the interaction of lactone-vitamin D3 with HADHA does not affect the HADHA enzymatic activity but instead limits biosynthesis of carnitine, an endogenous metabolite required for the transport of fatty acids into the mitochondria for β-oxidation. Lactone-vitamin D3 dissociates the protein-protein interaction of HADHA with trimethyllysine dioxygenase (TMLD), thereby impairing the TMLD enzyme activity essential in carnitine biosynthesis. These findings suggest a heretofore undescribed role of lactone-vitamin D3 in lipid β-oxidation and carnitine biosynthesis, and possibly in sunlight-dependent shifts of lipid metabolism in animals.

Pollutants enhance IgE sensitization in the gut via local alteration of vitamin D-metabolizing enzymes.

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 D3-metabolizing enzymes CYP27B1 and CYP24A1 in the gut and increased luminal levels of oxidized vitamin D3 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.

The Impact of Vitamin D on Skin Aging.

The active metabolites of vitamin D3 (D3) and lumisterol (L3) exert a variety of antiaging and photoprotective effects on the skin. These are achieved through immunomodulation and include anti-inflammatory actions, regulation of keratinocytes proliferation, and differentiation programs to build the epidermal barrier necessary for maintaining skin homeostasis. In addition, they induce antioxidative responses, inhibit DNA damage and induce DNA repair mechanisms to attenuate premature skin aging and cancerogenesis. The mechanism of action would involve interaction with multiple nuclear receptors including VDR, AhR, LXR, reverse agonism on RORα and -γ, and nongenomic actions through 1,25D3-MARRS receptor and interaction with the nongenomic binding site of the VDR. Therefore, active forms of vitamin D3 including its canonical (1,25(OH)2D3) and noncanonical (CYP11A1-intitated) D3 derivatives as well as L3 derivatives are promising agents for the prevention, attenuation, or treatment of premature skin aging. They could be administrated orally and/or topically. Other forms of parenteral application of vitamin D3 precursor should be considered to avoid its predominant metabolism to 25(OH)D3 that is not recognized by CYP11A1 enzyme. The efficacy of topically applied vitamin D3 and L3 derivatives needs further clinical evaluation in future trials.

Role of Hormones in Oral Squamous Cell Carcinoma - An Update

Background: Hormones have been recognized as regulator of the cell growth, differentiation and maturation. It has become increasingly evident that hormone may play a crucial role in the genesis and progression of several cancers like those of breast, ovary, testis, thyroid, prostrate including oral cancer.&#x0D; Aim: Present overview aims to discuss and provide data on possible role of various hormones including stress hormone, sex hormone, parathyroid and related hormone protein, melatonin and active metabolite of vitamin D3 in causation and progression of Oral squamous cell carcinoma (OSCC).&#x0D; Data Acquisition: A systematic search of existing literature was carried out for the keywords like hormones and cancer, hormones and oral cancer or OSCC utilizing the Google, Google Scholar and PubMed databases for extraction, assortment and compilation of data.&#x0D; Inference: In conclusion, we found that hormones are directly or indirectly involved in the pathogenesis of the OSCC and can be utilized in its management and prevention.

Safety of calcidiol monohydrate produced by chemical synthesis as a novel food pursuant to Regulation (EU) 2015/2283.

Following a request from the European Commission, the EFSA Panel on Nutrition, Novel Foods and Food Allergens (NDA) was asked to deliver an opinion on the safety of calcidiol monohydrate as a novel food (NF) pursuant to Regulation (EU) 2015/2283, including its bioavailability as a metabolite of vitamin D3 when added for nutritional purposes to food supplements. The NF is produced chemically. It is proposed in food supplements up to 10 μg/day for individuals ≥ 11 years of age, including pregnant and lactating women and up to 5 μg/day in 3‐ to 10‐year‐old children. The production process, composition, specifications and stability of the NF do not raise safety concerns. Animal and human data indicate efficient absorption. The NF contains a fraction of nanoparticles, which are fat soluble and unlikely to reach systemic distribution. There are no concerns regarding genotoxicity. Human adult studies do not raise safety concerns. Combined intake estimates of calcidiol from the NF and calcidiol and vitamin D from the diet were below the tolerable upper intake level (UL) for vitamin D for subjects above 11 years of age. The achieved mean serum 25(OH)D concentration in adults supplemented with 10 μg NF per day remained below 200 nmol/L. The Panel concludes that the NF is safe under the proposed conditions of use and use levels for individuals ≥ 11 years old, including pregnant and lactating women. The applicant did not provide data on the bioavailability and safety of the NF in children. The combined intake estimation in children (3–10 years) is close to the UL for vitamin D. Therefore, the Panel could not conclude on the safety of consumption of the NF in children (3–10 years) at the proposed daily intake. The NF is a bioavailable source of the biologically active metabolite of vitamin D, i.e. 1,25‐dihydroxyvitamin D.