The fate of vitamin D3 and indolylbutyric acid applied to cuttings of Populus tremula L. during adventitious root formation

Abstract Treatment of green cuttings of Populus tremula L. with vitamin D₃ enhances adventitious rooting and synergy is observed on simultaneous application with indolylbutyric acid. Translocation experiments with labelled vitamin D₃ and IBA, fed to the base of the cuttings, showed that such synergy was not due to an effect of one substance on the translocation of the other. When indolylbutyric acid was fed to the base of the cuttings, a high proportion was rapidly converted into conjugates which, on saponifaction, released inter alia indolylbutyric acid, but no indolylacetic acid. On the other hand, vitamin D₃ was metabolized to give products similar to those produced in non-sterile aqueous solutions of vitamin D₃ stored under the conditions of culture of the cuttings. Such a mixture is as effective as vitamin D₃ itself in promoting adventitious rooting. A preliminary examination of the products showed that extensive oxidation of vitamin D₃ had occurred and some of the individual components were synthesized and tested for their effect on rhizogenesis in P. tremula.     

Vitamin D in foods and as supplements

Numerous studies have shown that the vitamin D status is far from optimal in many countries all over the world. The main reason for this is lack of sunshine. Only a limited number of foods naturally contain vitamin D. Good sources of vitamin D(3) are fish (not only fatty fish), egg yolk, and offal such as liver. Some foods such as milk are fortified with vitamin D in some countries. Dietary vitamin D intake is low in many countries, especially as the dietary sources are limited. The use of supplements is important and seems to be high in some countries. Current dietary intake recommendations are too low to preserve/reach optimal S-25-OHD concentrations, when UVB radiation is not available. We suggest that the recommendations should be increased to at least 10 microg per day in all age groups when solar UVB is scarce. The elderly may need a daily vitamin D intake of 25 microg. If dietary intake of vitamin D is to be increased, food habits will have to change. From a public health point of view it is better to increase the potential sources of vitamin D by fortifying specific products that are consumed commonly in a whole population, or if necessary by especially vulnerable groups. Supplement use is probably the right alternative for vulnerable groups such as infants and inactive elderly in whom this is more easily implemented.     

Adventitious root formation in green cuttings of Populus tremula: Characterisation of the effect of vitamin D3 and indolylbutyric acid

Indolyl-3-butyric acid and vitamin D₃ enhance adventitious root formation in green cuttings of Populus tremula L. A significant synergistic effect is observed between these two substances. The number of roots formed on application of the individual substances and on simultaneous application depends on the growth substance concentration, the timing of application, the age of the cuttings and the number of leaves. Of the vitamin D₃ animal metabolites tested, only 1,25-dihydroxyvitamin D₃ markedly promoted adventitious rooting, and this to a lesser extent than vitamin D₃ itself. The 3-O-glucopyranosides of vitamin D₃ and the vitamin D₃ animal metabolites, promoted rooting to the same extent as the parent compounds.     

Vitamin D receptor gene polymorphisms (TaqI and ApaI) in relation to 25-hydroxyvitamin D levels and coronary artery disease incidence

Abstract

Context/objective: Previous studies have illustrated the association of the ApaI and TaqI polymorphisms of the vitamin D receptor gene, located in non-coding and coding regions, respectively, with diseases such as cancer and cardiovascular disease; however, investigating such association in Egyptian patients with coronary artery disease (CAD) has never been formerly attempted. Materials and methods: Male patients (n?=?137), 35–50 years of age, with verified CAD, were recruited alongside age- and sex-matched controls (n?=?58). Genotyping and 25-hydroxyvitamin D [25(OH)D] measurement were performed by polymerase chain reaction RFLP and HPLC, respectively. Results: Comparison of the genotypic distribution of both the TaqI and ApaI polymorphisms between patients and controls yielded insignificant results (p?=?0.55 and 0.7, respectively). Comparison of the allelic distribution of both polymorphisms also yielded insignificant results. The TaqI polymorphism was not found to predict 25(OH)D levels, whereas the wild-type genotype of the ApaI polymorphism was associated with greater levels of 25(OH)D (p?=?0.02), taking all subjects into consideration. Discussion/conclusion: This study presents the ApaI and TaqI polymorphisms as non-influencing players in the pathogenesis of CAD in Egyptian males and the ability of only the ApaI polymorphism to predict 25(OH)D levels, thus warranting further investigations of the triangular relationship between the polymorphisms, 25(OH)D and CAD incidence.     

Vitamin D status and nutrition in Europe and Asia

Vitamin D status is highly different in various countries of Europe, the Middle East and Asia. For this review, vitamin D deficiency is defined as serum 25-hydroxyvitamin D (25(OH)D) <25 nmol/l. Within European countries, serum 25(OH)D is <25 nmol/l in 2–30% of adults, increasing in the elderly and institutionalized to more than 80% in some studies. A north-south gradient was observed for serum 25(OH)D in the Euronut and MORE studies with higher levels in Scandinavia and lower levels in Italy and Spain and some Eastern European countries. This points to other determinants than sunshine, e.g. nutrition, food fortification and supplement use. Mean vitamin D intake in Scandinavia is 200–400 IU/d, twice that in other European countries. Very low serum 25(OH)D levels have been reported in the Middle East, e.g. Turkey, Lebanon, Jordan and Iran. In these countries serum 25(OH)D was lower in women than in men and associated with clothing habits. In a Lebanese survey, vitamin D deficiency was observed in the majority and occurred mainly in veiled women. In India, vitamin D deficiency was observed in more than 30%, vitamin D status being poor in school children, pregnant women and large cities. Vitamin D status was much better in Malaysia and Singapore, but lower serum 25(OH)D was observed in Japan and China. Rickets and osteomalacia appear quite common in India, but precise data are lacking. Immigrants in Europe from the Middle East and Asia carry a high risk for vitamin D deficiency, pregnant women being especially at risk. Comparison of vitamin D status between countries is hampered by interlaboratory variation of serum 25(OH)D measurement. In addition, there is a need of population-based data. In conclusion, vitamin D deficiency is common in Southern Europe, the Middle East, India, China and Japan. It is less common in Northern Europe and Southeast Asia. Risk groups are young children, the elderly, pregnant women and non-western immigrants in Europe. Important determinants are skin type, sex, clothing, nutrition, food fortification, supplement use, BMI and degree of urbanization.     

Screening of Vitamin D activity (VDA) of Solanum glaucophyllum leaves measured by radioimmunoassay (RIA)

The ingestion of Solanum glaucophyllum (SG) causes a calcinosis of cattle named Enteque Seco (ES). The toxic principle is the 1,25-(OH)₂D₃, mainly conjugated as glycoside. This study aims to validate a simple novel method of evaluation of the VDA of SG leaves. Aqueous extracts of SG were purified using C₁₈ minicolumns and assayed by RIA with an antibody raised in rabbits by injection of the acid—C22, 1-(OH)Vitamin D₃. Data were expresed as glycoside equivalent to 1,25-(OH)₂D₃ in ng/g of dry leaves. We compared this data with 1,25-(OH)₂D₃ levels measured, in the same samples, by liquid chromatography (HPLC) after enzyme cleavage. This procedure involved the incubation of SG leaves with rumen fluid, followed by C₁₈-OH solid phase extraction. The 1,25-(OH)₂D₃ fraction was run by HPLC and detection was achieved using a photodiode array detector. Data were expressed as micrograms of 1,25-(OH)₂D₃/g dry leaves. A significant regression of 1,25-(OH)₂D₃ levels (Y) as a function of glycoside RIA 1,25-(OH)₂D₃ equivalents (X) was found: Y = 12.02 + 0.35X [R = 0.81; P = 0,0002; N = 15], allowing us to conclude that this novel assay could be used to estimate the amount of this active principle contained in SG leaves.     

Characterization of rat and human CYP2J enzymes as Vitamin D 25-hydroxylases

vitamin D is 25-hydroxylated in the liver, before being activated by 1alpha-hydroxylation in the kidney. Recently, the rat cytochrome P450 2J3 (CYP2J3) has been identified as a principal vitamin D 25-hydroxylase in the rat [Yamasaki T, Izumi S, Ide H, Ohyama Y. Identification of a novel rat microsomal vitamin D3 25-hydroxylase. J Biol Chem 2004;279(22):22848-56]. In this study, we examine whether human CYP2J2 that exhibits 73% amino acid homology to rat CYP2J3 has similar catalytic properties. Recombinant human CYP2J2 was overexpressed in Escherichia coli, purified, and assayed for vitamin D 25-hydroxylation activity. We found significant 25-hydroxylation activity toward vitamin D3 (turnover number, 0.087 min(-1)), vitamin D2 (0.16 min(-1)), and 1alpha-hydroxyvitamin D3 (2.2 min(-1)). Interestingly, human CYP2J2 hydroxylated vitamin D2, an exogenous vitamin D, at a higher rate than it did vitamin D3, an endogenous vitamin D, whereas, rat CYP2J3 hydroxylated vitamin D3 (1.4 min(-1)) more efficiently than vitamin D2 (0.86 min(-1)). Our study demonstrated that human CYP2J2 exhibits 25-hydroxylation activity as well as rat CYP2J3, although the activity of human CYP2J2 is weaker than rat CYP2J3. CYP2J2 and CYP2J3 exhibit distinct preferences toward vitamin D3 and D2.     

Vitamin D status and determinants of deficiency in non-supplemented athletes during the winter months in Tunisia

Recent reports suggest that hypovitaminosis D in athletes is as common as in the general population. This study was devised to examine vitamin D status and determinants of deficiency in athletes living in a sunny country (Tunisia). One hundred and fifty national elite athletes, training outdoors (n = 83) or indoors (n = 67), were enrolled from January to February 2012. Plasma 25-hydroxyvitamin D was measured by radioimmunoassay. Concentrations were between 50 and 75 nmol · l^-1 in 21.3% of participants, between 25 and 50 nmol · l^-1 in 55.3% of participants and <25 nmol · l^-1 in 14.7% of participants. The concentrations were significantly lower in indoor athletes than outdoor athletes (36.2±19.0 nmol · l^-1 vs. 49.1±19.2 nmol · l^-1; p < 0.001). In multivariate analysis, vitamin D deficiency (25-hydroxyvitamin D <50 nmol · l^-1) was associated with indoor sports [multi-adjusted odds ratio (95% confidence interval), 5.03 (1.64-15.4); p = 0.005], female gender [3.72 (1.44-9.65); p = 0.007] and age < 18 years [2.40 (1.01-5.85); p = 0.05]. Athletes living in sun-rich environments are exposed to a high risk of vitamin D inadequacy. Given the importance of vitamin D in health and athletic ability, targeting sufficient levels of plasma 25-hydroxyvitamin D in athletes is well justified.     

Caffeine decreases vitamin D receptor protein expression and 1,25(OH)2D3 stimulated alkaline phosphatase activity in human osteoblast cells

Of the various risk factors contributing to osteoporosis, dietary/lifestyle factors are important. In a clinical study we reported that women with caffeine intakes >300 mg/day had higher bone loss and women with vitamin D receptor (VDR) variant, tt were at a greater risk for this deleterious effect of caffeine. However, the mechanism of how caffeine effects bone metabolism is not clear. 1,25-Dihydroxy vitamin D₃ (1,25(OH)₂D₃) plays a critical role in regulating bone metabolism. The receptor for 1,25(OH)₂D₃, VDR has been demonstrated in osteoblast cells and it belongs to the superfamily of nuclear hormone receptors. To understand the molecular mechanism of the role of caffeine in relation to bone, we tested the effect of caffeine on VDR expression and 1,25(OH)₂D₃ mediated actions in bone. We therefore examined the effect of different doses of caffeine (0.2, 0.5, 1.0 and 10 mM) on 1,25(OH)₂D₃ induced VDR protein expression in human osteoblast cells. We also tested the effect of different doses of caffeine on 1,25(OH)₂D₃ induced alkaline phosphatase (ALP) activity, a widely used marker of osteoblastic activity. Caffeine dose dependently decreased the 1,25(OH)₂D₃ induced VDR expression and at concentrations of 1 and 10 mM, VDR expression was decreased by about 50–70%, respectively. In addition, the 1,25(OH)₂D₃ induced alkaline phosphatase activity was also reduced at similar doses thus affecting the osteoblastic function. The basal ALP activity was not affected with increasing doses of caffeine. Overall, our results suggest that caffeine affects 1,25(OH)₂D₃ stimulated VDR protein expression and 1,25(OH)₂D₃ mediated actions in human osteoblast cells.     

Vitamin D and metabolic health with special reference to the effect of vitamin D on serum lipids

Considering that the vitamin D receptor as well as the 1-α-hydroxylase enzyme that converts 25-hydroxyvitamin D (25(OH)D) to its active form 1,25-dihydroxyvitamin D have been found in tissues throughout the body, it is likely that vitamin D is important for more than the calcium balance. Accordingly, low serum levels of 25(OH)D have been associated with mortality, cardiovascular disease, type 2 diabetes, hypertension and obesity. Low serum levels of 25(OH)D have also been associated with an unfavourable lipid profile, which could possible explain the relation with cardiovascular disease and mortality. However, the relation between vitamin D and lipids have so far received little attention and is therefore the main focus of the present review. A PubMed search identified 22 cross-sectional studies where serum levels of 25(OH)D and lipids were related and that included a minimum of 500 subjects, and 10 placebo-controlled double-blind intervention studies with vitamin D where more than 50 subjects were included. In all the cross-sectional studies serum 25(OH)D was positively associated with high-density lipoprotein cholesterol (HDL-C) resulting in a favourable low-density lipoprotein cholesterol (LDL-C) (or total cholesterol) to HDL-C ratio. There was also a uniform agreement between studies on a negative relation between serum 25(OH)D and triglycerides (TG). On the other hand, the intervention studies gave divergent results, with some showing a positive and some a negative effect of vitamin D supplementation. However, none of the intervention studies were specifically designed for evaluating the relation between vitamin D and lipids, none had hyperlipemia as an inclusion criterion, and none were sufficiently powered. In only one study was a significant effect seen with an 8% (0.28 mmol/L) increase in serum LDL-C and a 16% (0.22 mmol/L) decrease in serum TG in those given vitamin D as compared to the placebo group. Accordingly, the effect of vitamin D supplementation on serum lipids is at present uncertain. Considering the numerous other promising vitamins and minerals that when properly tested have been disappointing, one should wait for the results of forthcoming vitamin D intervention studies before drawing conclusions on potential beneficial effects of vitamin D.     

Altered downstream target gene expression of the placental Vitamin D receptor in human idiopathic fetal growth restriction

Fetal growth restriction (FGR) affects up to 5% of pregnancies and is associated with significant perinatal complications. Maternal deficiency of vitamin D, a secosteroid hormone, is common in FGR-affected pregnancies. We recently demonstrated that decreased expression of the vitamin D receptor (VDR) in idiopathic FGR placentae could impair trophoblast growth. As strict regulation of cell-cycle genes in trophoblast cells is critical for optimal feto-placental growth, we hypothesised that pathologically decreased placental VDR contributes to aberrant regulation of cell-cycle genes. The study aims were to (i) identify the downstream cell-cycle regulatory genes of VDR in trophoblast cells, and (ii) determine if expression was changed in cases of FGR. Targeted cell-cycle gene cDNA arrays were used to screen for downstream targets of VDR in VDR siRNA-transfected BeWo and HTR-8/SVneo trophoblast-derived cell lines, and in third trimester placentae from FGR and gestation-matched control pregnancies (n = 25 each). The six candidate genes identified were CDKN2A, CDKN2D, HDAC4, HDAC6, TGFB2 and TGFB3. TGFB3 was prioritised for further validation, as its expression is largely unknown in FGR. Significantly reduced mRNA and protein expression of TGFB3 was verified in FGR placentae and the BeWo and HTR-8/SVneo trophoblast cell lines, using real-time PCR and immunoblotting respectively. In summary, decreased placental VDR expression alters the expression of regulatory cell-cycle genes in FGR placentae. Aberrant regulation of cell-cycle genes in the placental trophoblast cells may constitute a mechanistic pathway by which decreased placental VDR reduces feto-placental growth.     

Synthesis of some substituted pyrazinopyridoindoles and 3D QSAR studies along with related compounds: piperazines, piperidines, pyrazinoisoquinolines, and diphenhydramine, and its semi-rigid analogs as antihistamines (H1)

3D QSAR studies on the title compounds led to the development of a model with three biophoric sites and six secondary sites viz. H-acceptor (ACC), H-donor (DON), heteroatom (presence), hydrophobic (hydrophobicity), steric (refractivity), and a ring (presence) along with total hydrophobicity and total refractivity as global properties. The model predicted the test set of compounds reasonably well. Three of the five newly synthesized 2-substituted octahydropyrazinopyridoindoles have shown potent antihistaminic H₁ activity with less toxicity and sedation potential.     

Vitamin D status in a Brazilian cohort of adolescents and young adults with perinatally acquired human immunodeficiency virus infection

The purpose was to determine the prevalence and related factors of vitamin D (VitD) insufficiency in adolescents and young adults with perinatally acquired human immunodeficiency virus. A cohort of 65 patients (17.6 ± 2 years) at the Federal University of Rio de Janeiro, Brazil, were examined for pubertal development, nutrition, serum parathormone and serum 25-hydroxyvitamin D [s25(OH)D]. s25(OH)D levels < 30 ng/mL (< 75 nmol/L) were defined as VitD insufficiency. CD4⁺ T-cell counts and viral load, history of worst clinical status, immunologic status as nadir, current immunologic status, and antiretroviral (ART) regimen were also evaluated as risk factors for VitD insufficiency. Mean s25(OH)D was 37.7 ± 13.9 ng/mL and 29.2% had VitD insufficiency. There was no difference between VitD status and gender, age, nutritional status, clinical and immunological classification, and type of ART. Only VitD consumption showed tendency of association with s25(OH)D (p = 0.064). Individuals analysed in summer/autumn season had a higher s25(OH)D compared to the ones analysed in winter/spring (42.6 ± 14.9 vs. 34.0 ± 11.9, p = 0.011). Although, the frequency of VitD insufficiency did not differ statistically between the groups (summer/autumn 17.9% vs. winter/spring 37.8%, p = 0.102), we suggest to monitor s25(OH)D in seropositive adolescents and young adults, especially during winter/spring months, even in sunny regions.     

Exploring the structural requirements for jasmonates and related compounds as novel plant growth regulators: A current computational perspective

Jasmonates and related compounds have been highlighted recently in the field of plant physiology and plant molecular biology due to their significant regulatory roles in the signaling pathway for the diverse aspects of plant development and survival. Though a considerable amount of studies concerning their biological effects in different plants have been widely reported, the molecular details of the signaling mechanism are still poorly understood. This review sheds new light on the structural requirements for the bioactivity/property of jasmonic acid derivatives in current computational perspective, which differs from previous research that mainly focus on their biological evaluation, gene and metabolic regulation and the enzymes in their biosynthesis. The computational results may contribute to further understanding the mechanism of drug-receptor interactions in their signaling pathway and designing novel plant growth regulators as high effective ecological pesticides.Key words: jasmonates, amino acid conjugates of jasmonic acid, plant growth regulators, quantitative structure-activity relationship, quantitative structure-property relationship, a mini-review     

Vitamin D Stimulates Cardiomyocyte Proliferation and Controls Organ Size and Regeneration in Zebrafish

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Vitamin D status and vitamin D receptor gene polymorphisms and susceptibility to type 1 diabetes in Egyptian children

Background

Type 1 diabetes mellitus (T1DM) is recognized as a T-cell-mediated autoimmune disease. Vitamin D compounds are known to suppress T-cell activation by binding to vitamin D receptor (VDR); and thus, VDR gene polymorphisms may be related to T-cell-mediated autoimmune diseases. The aim of this study was to investigate the association between vitamin D status and VDR gene polymorphisms and T1DM.

Materials and methods

One hundred and twenty patients with T1DM and one hundred and twenty controls were enrolled in the study. VDR gene BsmI, FokI, ApaI and TaqI polymorphisms were determined using polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP). Serum 25-hydroxyvitamin D (25(OH)D) was determined using ELISA.

Result

Serum 25(OH)D levels revealed a vitamin D deficiency or insufficiency in 75% of the patients. The mean levels of vitamin D were significantly lower in patients as compared to their controls (P = < 0.001). VDR BsmI Bb and bb genotypes and VDR FokI Ff and ff genotypes were associated with increased risk of T1DM (OR = 2.3, 95% CI = 1.3–4.2, P = 0.005; OR = 2.2, 95% CI = 1.1–4.7, P = 0.04; OR = 1.8, 95% CI = 1.03–3.04, P = 0.04; OR = 4.03, 95% CI = 1.2–13.1, P = 0.01 respectively), while the VDR ApaI and TaqI polymorphisms were not.

Conclusion

Our study indicated that vitamin D deficiency and VDR BsmI and FokI polymorphisms were associated with T1DM in Egyptian children.     

1,25-Dihydroxyvitamin D3 Controls a Cohort of Vitamin D Receptor Target Genes in the Proximal Intestine That Is Enriched for Calcium-regulating Components

1,25-Dihydroxyvitamin D₃ (1,25(OH)₂D₃) plays an integral role in calcium homeostasis in higher organisms through its actions in the intestine, kidney, and skeleton. Interestingly, although several intestinal genes are known to play a contributory role in calcium homeostasis, the entire caste of key components remains to be identified. To examine this issue, Cyp27b1 null mice on either a normal or a high calcium/phosphate-containing rescue diet were treated with vehicle or 1,25(OH)₂D₃ and evaluated 6 h later. RNA samples from the duodena were then subjected to RNA sequence analysis, and the data were analyzed bioinformatically. 1,25(OH)₂D₃ altered expression of large collections of genes in animals under either dietary condition. 45 genes were found common to both 1,25(OH)₂D₃-treated groups and were composed of genes previously linked to intestinal calcium uptake, including S100g, Trpv6, Atp2b1, and Cldn2 as well as others. An additional distinct network of 56 genes was regulated exclusively by diet. We then conducted a ChIP sequence analysis of binding sites for the vitamin D receptor (VDR) across the proximal intestine in vitamin D-sufficient normal mice treated with vehicle or 1,25(OH)₂D₃. The residual VDR cistrome was composed of 4617 sites, which was increased almost 4-fold following hormone treatment. Interestingly, the majority of the genes regulated by 1,25(OH)₂D₃ in each diet group as well as those found in common in both groups contained frequent VDR sites that likely regulated their expression. This study revealed a global network of genes in the intestine that both represent direct targets of vitamin D action in mice and are involved in calcium absorption.