Different Forms Of Vitamin Research Articles

Association between dietary vitamin E and osteoporosis in older adults in the United States.

Increased oxidative stress due to aging can lead to increased bone loss. The most abundant form of vitamin E, namely α-tocopherol, has high antioxidant properties and biological activity; however, its effect on osteoporosis has not been well studied in humans. We aimed to investigate the association between dietary vitamin E (α-tocopherol) and osteoporosis among older adults in the United States. This cross-sectional study analyzed data on older adults in the United States aged ≥50 years from the 2007-2010, 2013-2014 and 2017-2020 pre-pandemic cycles of the National Health and Nutrition Examination Survey. Sample-weighted multivariate regression models were used, with adjustments for relevant confounders. This study comprised 5,800 individuals with available data on dietary intake and bone mineral density of hip and spine. The mean participant age was 61.4 (standard deviation, 8.7) years, and approximately 9.9% had osteoporosis. High vitamin E intake was significantly associated with a reduced risk of osteoporosis (odds ratio, 0.96, 95% confidence interval, 0.93-0.98). In addition, there was evidence of interaction between dietary vitamin E and prior fracture on preventing osteoporosis. Our study indicated a linear association between dietary vitamin E levels and osteoporosis in an older population in the United States. Further research is required to explore the potential effects of different forms of vitamin E on osteoporosis.

Vitamin C, lactoferrin and elastin-Advancing the science.

This study follows an initial scientific validation linking sodium ascorbate (SAC) with elastin conservation and the clinical trial histology observation that the full formulation tested there stimulated elastin development. In an effort to explain the increased elastin response, a candidate was sought that may provide synergy to SAC during elastin stimulation. Lactoferrin was the constituent chosen to explore in this realm. Using the previously described exvivo skin model, freshly collected discarded human skin from 2 donors was used to evaluate the effects of lactoferrin and SAC alone and together, and L-ascorbate CE Ferulic formulation (CEF) on elastogenesis. Four skin explants were topically subjected to the treatments daily for 7 days and one group was left untreated as a negative control. The tissue was fixed and embedded. Sections were evaluated by immunofluorescence using antibodies targeting Tropoelastin and CD44, with DAPI counterstaining to observe nuclei. Images were then analyzed using ImageJ. Treatment with SAC and lactoferrin demonstrated a significant synergistic effect on tropoelastin stimulation compared to the single treatments. In addition, this combination demonstrated intact and increased elastin fibers in contrast to the CEF, which portrayed fragmented elastin fibers. In addition, an additive effect of SAC also contributed to the enhanced CD44, suggesting an increased presence of hyaluronic acid, a new observation for this compound. This study complements a series of studies that have been undertaken to validate the efficacy of a novel antioxidant formulation. Aside from its efficacy in ROS management, the SAC constituent is unique in the different forms of Vitamin C for its ability to conserve elastin. Prior clinical studies demonstrated additive elastin stimulation on histology, not just conservation. From this current study, the combination of SAC with lactoferrin may be responsible for this additive stimulatory effect on elastin. This presents a significant advance in topical antioxidant formulations where the Vitamin C component provides antioxidant and collagen stimulation with additional elastin stimulation rather than degradation.

Determination of vitamins K1 and K3 in green tea and in pharmaceutical supplements by capillary micellar electrokinetic chromatography

A method based on capillary micellar electrokinetic chromatography (MEKC) was developed for vitamin K1 and K3 determination. Experimental and instrumental parameters optimized for electrophoretic separation with better peak efficiency were: borate buffer at 0.05 mol L−1, pH 8.5, cetyltrimethylammonium bromide (CTAB) at 0.05 mol L−1, acetonitrile 20 % v/v, 25 °C and a negative potential difference of 30 kV. Sample introduction was made by hydrodynamic at 50 mbar for 15 s. Migration times for vitamins K1 and K3 were (5.2 ± 0.1) and (3.4 ± 0.1) min respectively. Limits of detection and quantification were on the order of 10−5 g L−1 and 10−4 g L−1. For vitamin K1, the precision was between 2 and 7 % for the peak area. Recoveries were 101 ± 2 % and 103 ± 2 % for green tea and vitamin supplement samples, respectively. For vitamin K3, recoveries were 99 ± 3 % for vitamin supplement. Comparative tests were performed with the reference method based on liquid chromatography with agreement of results. The uncertainty and the contribution of the relevant sources was carefully evaluated. The method was found adequate to enable reliable and sensitive measurements of different forms of vitamin K with low consumption of solvents and less generation of waste.

Association of Vitamin E and Cognitive Decline in Older Adults with and without the APOEɛ4 Allele: A Biracial Population-Based Community Study.

The association of different types of tocopherols (vitamin E) with cognition might vary by the APOEɛ4 allele status. We examined the association of dietary tocopherols with cognitive decline among participants with and without the APOEɛ4 allele over a median of 12 years. 2,193 participants from the Chicago Health and Aging Project were included in the analyses. Global cognition was assessed in three-year cycles. We used a 144-item FFQ to assess dietary intakes of tocopherols and hME Sequenom mass-array platform to assess APOE genotype. We used linear mixed effects models to examine the relationship between tocopherol from food sources and global cognitive decline. The mean baseline age was 74.1 (SD = 5.9) years. Among APOEɛ4 carriers, participants in the highest quintile of intakes of dietary vitamin E had a slower cognitive decline of 0.022 SDU (95% CI: 0.000, 0.043) compared to those in the lowest quintile. A higher intake of dietary α-tocopherol from food sources only was associated with slower cognitive decline in APOEɛ4 carriers (p for trend 0.002) but not among the non-carriers (p for trend 0.937). Among APOEɛ4 carriers, those in the highest quintile of intake of α-tocopherol had a 16.4% slower rate of decline of global cognition compared to those in the lowest quintile (β= 0.034, 95% CI: 0.013, 0.054). Individuals consuming high α-tocopherol from food sources had slower cognitive decline among APOEɛ4 carriers. In older adults, different forms of vitamin E might moderate the relationship of APOEɛ4 with global cognition.

Countercurrent chromatography separation of vitamin E isomers in a co-current mode.

Vitamin E represents a group of lipophilic phenolic compounds, including α-tocopherol, β-tocopherol, γ-tocopherol, and δ-tocopherol, and α-tocotrienol, β-tocotrienol, γ-tocotrienol, and δ-tocotrienol isomers. Different forms of vitamin E have been proven to exhibit varying biological activities. However, due to their structural similarities, the separation of vitamin E isomers is a challenging task. Therefore, it is crucial to establish an efficient method for isolating individual isomers. In this study, co-current countercurrent chromatography was employed to isolate vitamin E isomers from commercial capsules using a n-heptane-methanol-water (10:9.5:0.5, v/v) solvent system. The partition coefficients of the main constituents in the capsules ranged from 0.94 to 6.23, requiring over 450 min for a complete separation. To improve separation efficiency, a co-current elution mode was implemented and the flow rates of the two liquid phases as well as sample amount were examined. The results suggested that increasing the flow rate of the stationary phase and sample size could result in more effective separation, shorter separation time, and higher yield. It proved that co-current countercurrent chromatography was an effective method for the separation of vitamin E isomers.

Deposition and bioconversion law of β-carotene in laying hens after long-term supplementation under adequate vitamin A status in the diet

β-Carotene, because it is the precursor of vitamin A and has versatile biological roles, has been applied as a feed additive in the poultry industry for a long time. In this study, we investigated the deposition and bioconversion of β-carotene in laying hens. A total of 600 Hy-line brown laying hens at 40 wk of age were randomly divided into 5 dietary treatments, each group's dietary supplemental levels of β-carotene were 0, 15, 30, 60, 120 mg/kg feed, and the vitamin A levels were all 8,000 IU/kg. After 14-wk trial, samples were collected, then carotenoids and different forms of vitamin A were detected using the novel method developed by our laboratory. We found that dietary β-carotene treatment had no significant effects on laying hens' production performance and egg quality (P > 0.05), except the yolk color. The deposition of β-carotene in the body gradually increased (P < 0.01) with the supplemental dose, whereas the contents of lutein and zeaxanthin decreased (P < 0.05). When the β-carotene supplemental level was above 30 mg/kg in the diet, the different forms of vitamin A in in serum, liver, ovary, and yolks were increased compared to the control group (P < 0.05). However, these indicators decreased when the additional dose was 120 mg/kg. Moreover, the mRNA levels of the genes involved in β-carotene absorption, bioconversion, and negative feedback regulation in duodenal mucosa and liver were upregulated after long-term feeding (P < 0.05). Histological staining of the ovaries indicated that the deposition of β-carotene led to a lower rate of follicle atresia (P < 0.05), and this positive effects may be related to the antioxidant function of β-carotene, which caused a reduction of oxidation products in the ovary (P < 0.05). Altogether, β-carotene could accumulate in laying hens intactly and exert its biological functions in tissue. Meanwhile, a part of β-carotene could also be converted into vitamin A but this bioconversion has an upper limit and negative feedback regulation.

Vitamin D Content in Commonly Consumed Mushrooms in Thailand and Its True Retention after Household Cooking.

This study investigated the vitamin D level of nine species of cultivated mushrooms and three species of wild mushrooms commonly consumed in Thailand and the effect of cooking on their vitamin D content. Cultivated mushrooms were obtained from three wholesale markets, while wild mushrooms were collected from three trails in a conservation area. Mushrooms from each source were separated into four groups: raw, boiled, stir-fried, and grilled. Different forms of vitamin D were analyzed using liquid chromatography with tandem mass spectrometry (LC-MS/MS). The analyzed method demonstrated good linearity, accuracy, and precision, as well as being low in the limit of detection and limit of quantitation. Results showed that vitamin D2 and ergosterol (provitamin D2) were the major forms of vitamin D found in the mushrooms. Both raw cultivated and wild mushrooms had wide ranging ergosterol contents (7713-17,273 μg/100 g edible portion, EP). Lung oyster mushroom and termite mushroom contained high levels of vitamin D2 (15.88 ± 7.31 and 7.15 ± 0.67 μg/100 g EP, respectively), while other mushroom species had negligible amounts (0.06 to 2.31 μg per 100 g EP). True retention (TR) levels of vitamin D2 after boiling, stir-frying, and grilling were not significantly different (p > 0.05) (with estimated marginal means ± standard error 64.0 ± 2.3%, 58.8 ± 2.3%, and 64.7 ± 3.6% TR, respectively). Consuming cooked lung oyster mushrooms, in particular, along with regular exposure to sunlight should be promoted to reduce the incidence of vitamin D deficiency.

Properties, forms and biological effects of vitamin C in skin therapies

Due to its properties, vitamin C is one of the most popular ingredients in cosmetic products. It is found in ampoules, serums, masks, or creams. Depending on the form of the vitamin that is contained in a particular product, its action may differ. The aim of this article was to collect the latest information and analyze the results of studies on the effects of different forms of vitamin C on the skin. Vitamin C is one of the leading substances used in beauty salons as well as in-home care. It exhibits a strong antioxidant effect, protects the skin against the appearance of premature signs of skin aging, and is used in the treatment of the discoloration. There are also published reports on the use of vitamin C in therapies supporting the treatment of cancer.

Influence of vitamin D metabolites on vitamin D status, immunity and gut health of piglets

Immediately post-weaning, piglets are prone to gastrointestinal infectious diseases. The active metabolite of vitamin D 1,25-dihydroxyvitamin D has direct impact on immune cell function and responses. Thus, a low vitamin D status may compromise the immune responses during infectious diseases. The aim of this study was to examine the effect of supplementation of different forms of vitamin D (25-OH-D3 and vitamin D3) to suckling piglets’ vitamin D status at weaning. In addition, to determine whether the vitamin D status could affect the immune development in piglets and their robustness against E. coli challenge. Genetically E. coli F4 susceptible litters of piglets were divided into two treatment groups: group 1 (n = 16) provided milk formula supplemented with vitamin D3 (CON), and group 2 (n = 16) provided milk formula supplemented with 25-OH-D3 (TREAT). Piglets were offered the experimental milk formulas from day 3 after farrowing until weaning (at day 28 of age). A commercial weaner diet with high protein content were provided to induce weaning stress. Milk formulas, sow and weaner diets as well as plasma and milk samples obtained from sows (n = 8) were analysed for vitamin D metabolites. Vitamin D status in piglets was investigated by collection of plasma samples on day 3, 15, 28 and 35 of age. Eight piglets randomly selected from each dietary group (in total 16 pigs) were inoculated with E. coli F4 O149 on day 2 and 3 post-weaning. Blood samples collected on day 2 and 9 post-weaning (pre- and post E. coli inoculation, respectively) were analysed for haematological and immunological parameters including immunoglobulins, antibodies specific to E. coli O149 K88, cytokines and C-reactive protein. In addition, intestinal samples were obtained one week after E. coli inoculation to study the influence of infection and vitamin D status on immune responses at different sites of the intestine. This was accomplished by gene expression of various cytokines and tight junction proteins. In general, vitamin D status of the piglets were low. However, piglets provided TREAT during the suckling period had increased vitamin D status at weaning compared to piglets provided CON. Vitamin D was used during activation of the immune system as pigs inoculated with E. coli had lower plasma concentrations of 25-OH-D3 than non-inoculated pigs possibly due to mobilising of vitamin D in the liver. Hence, increased vitamin D status at weaning might improve piglets’ resistance to E. coli infection.

Development and application of a SFC–DAD–MS/MS method to determine carotenoids and vitamin A in egg yolks from laying hens supplemented with β-carotene

β-Carotene, a provitamin A carotenoid, can be converted into vitamin A in animals’ bodies, and can also be accumulated intactly in many animal products. In this study, supercritical fluid chromatography–tandem mass spectrometry was utilized to determine β-carotene and different forms of vitamin A in eggs simultaneously. According to the results, β-carotene contained in yolk reached a plateau after about 2 weeks of supplementation. With an increase in dietary supplement level, the amount of β-carotene gradually increased, as well as slightly changing the yolk color. Moreover, the contents of retinoids including retinol, retinyl propionate, retinyl palmitate and retinyl stearate were also elevated in yolks with the β-carotene additive levels; meanwhile, the lutein and zeaxanthin decreased. On the whole, β-carotene in the diet of laying hens could be partially deposited in egg yolk, and the contents of vitamin A in yolk could be increased due to β-carotene bioconversion.

Mechanisms of action of vitamin D in delaying aging and preventing disease by inhibiting oxidative stress.

Although several recent studies have shown that vitamin D supplementation beneficially decreases oxidative stress parameters, there is no consensus on this subject in humans. Thus the role of vitamin D supplementation has recently become a controversial topic because large intervention studies in humans have not shown significant benefits. These studies have indicated that supplementation with precursor forms of active vitamin D has no effect on all-cause mortality, cannot reduce the fracture risk of the elderly, cannot reduce the incidence of cancer or cardiovascular disease in the elderly, and cannot significantly reduce the incidence risk of diabetes in the elderly. However, a link between several age-related diseases and enhanced oxidative stress has been found in mice with insufficient or deficient 1,25-dihydroxyvitamin D (1,25(OH)2D), the active form of vitamin D, which indicates that reduced active vitamin D accelerates aging and age-related diseases by increasing oxidative stress. Furthermore, supplementation of exogenous 1,25(OH)2D3, or antioxidants, could dramatically postpone aging, prevent osteoporosis and spontaneous tumor development induced by 1,25(OH)2D insufficiency or deficiency, by inhibiting oxidative stress. Mechanistically, the antioxidative effects of 1,25(OH)2D3 are carried out via the vitamin D receptor (VDR) by activation of the Nrf2 oxidative stress response pathway though transcriptional or posttranscriptional activation of Nrf2 or transcriptional upregulation of Sirt1 and Bmi1 expression. Whether discrepancies between studies in humans and in mice reflect the different forms of vitamin D examined remains to be determined.

Effect of different doses of cholecalciferol and calcidiol on meat quality parameters and skeletal muscle transcriptome profiles in swine

Skeletal muscle tissue is one of the potential targets for vitamin D actions. There are indications that vitamin D supplementation to swine has a positive effect on meat quality. However, these issues need further study, especially in terms of response to the use of different forms of vitamin D. We carried out a multi-purpose study to compare the effects of cholecalciferol and calcidiol on meat quality and muscle tissue transcriptome. Meat quality assessment and gene expression analysis were performed on longissimus dorsi samples collected from swine fed grower/finisher diets containing 2000 IU cholecalciferol/1500 IU cholecalciferol per kg (n = 8), 3000 IU cholecalciferol/2500 IU cholecalciferol per kg (n = 10), 2000 IU cholecalciferol +1000 IU calcidiol/1500 IU cholecaliferol +1000 IU calcidiol per kg (n = 8), and 2000 IU calcidiol/1500 IU calcidiol per kg (n = 8). The results suggest that increasing the dose of cholecalciferol and using calcidiol in the diet of finishers may improve meat texture parameters (shear force P = 0,014, toughness P = 0,048, cohesiveness P = 0,017, resilience P = 0,002). Shear force (68.46 N–51.42 N) and toughness (145.85 N–114.52 N) decreased the most under the effect of increasing cholecalciferol dosage. In turn, cohesiveness (0.60 N–0.65 N) and resilience (0.23 N–0.28 N) increased most strongly under the use of cholecalciferol+calcidiol. Moreover, the results indicate no significant effect of increasing cholecalciferol dose and use calcidiol in the swine diet on muscle tissue transcriptome.

Different associations of varying types of Vitamin E and cognitive function in older adults with or without APOE Ɛ4 allele

AbstractBackgroundDifferent forms of vitamin E may have a different association with cognitive function, which might vary by the APOE E4 allele status. We aim to examine vitamin E from different sources and in varying forms and their relation to cognitive decline among those with and without the APOE E4 allele.MethodsWe included 2,014 participants from the Chicago Health and Aging Project (62% African Americans, 63% female). Global cognition was assessed using a composite score of episodic memory, perceptual speed, and the MMSE. Diet was assessed by a 139‐item FFQ. APOE genotype was assessed by hME Sequenom mass‐array platform. Mixed models were adjusted for age, sex, education, smoking status, calorie intake, alcohol consumption, use of supplements, time since baseline, and the interaction term of time with each covariate.ResultsA higher dietary vitamin E was associated with slower cognitive decline. Those in the highest quintile of dietary vitamin E intake had 28% slower cognitive decline than the lowest quintile (β = 0.014, p = 0.02). A higher intake of dietary αlpha‐tocopherol was associated with slower cognitive decline in participants with APOE E4 allele, but not among those without. In participants with APOE E4 allele and in the highest quintile of alpha‐tocopherol intake had a 16.4% slower rate of global cognitive decline than those in the lowest quintile (β = 0.015, p = 0.0015). A higher intake of delta‐tocopherol was associated with a slower decline in individuals without the APOE E4 allele only. Among those without the APOE E4 allele and in the highest quintile, the rate of global cognitive decline was slower by 22% than the lowest quintile (β = 0.012, p = 0.0014). We found no significant associations between beta‐ and gamma‐tocopherol intakes and cognitive decline among those with and without the APOE E4 allele.ConclusionOur study found a positive association of alpha‐tocopherol with cognitive decline among those with the APOE E4 allele and delta‐tocopherol with the decline in those without the APOE E4 allele. Our findings suggest that different forms of vitamin E might have a different association with cognitive decline in older adults depending on their APOE E4 allele status.

Effect of the administration of different forms of vitamin D on central blood pressure and aortic stiffness, and its implication in the reduction of albuminuria in chronic kidney disease

Background and objectivesVitamin D (vitD) participates in phospho-calcium metabolism and exerts multiple pleiotropic effects. There is tissue 1-α (OH)ase that converts 25-OH cholecalciferol (25 (OH) D) in calcitriol that exerts autocrine and paracrine effects. 25 (OH)D deficiency could limit these tissue effects of vitD. The administration of nutritional vitD and the activator of the vitD receptor, paricalcitol, may promote beneficial effects on vascular and renal function. The objective of this work was to study in subjects with chronic kidney disease (CKD) the effect that the administration of different forms of vitD has on arterial function and albuminuria, and the possible relationship between the modifications of these variables. Patients and methodsWe studied in 97 patients with CKD stages 3–4 the effect of the administration of cholecalciferol (group 2; n: 35) and paricalcitol (n: 31; group 3) on parameters derived from brachial blood pressure, aortic blood pressure and on aortic stiffness studied using carotid-femoral pulse velocity (Vpc-f), and on albuminuria. A group of patients with stages 3–4 CKD who did not receive vitD therapy served as a control group (n: 31; group 1). All parameters were studied at baseline and after the follow-up period which was 7±2 months. ResultsIn the baseline phase, no differences were observed between the groups in brachial systolic blood pressure (bSBP), central systolic blood pressure (SBP), brachial pulse pressure (bPP), and central pulse pressure (pCP) or in aortic stiffness that was increased in all groups with a baseline Vpc-f value of 10.5 (9.2–12.1) m/sec. The baseline albuminuria value in the grouped patients was 229 (43–876) mg/g (median (interquartile range)), with no differences between the groups.Serum calcium and phosphorus increased significantly in those treated with cholecal-ciferol (native vitD) and paricalcitol (active vitD). Parathormone (PTH) values ​​decreased in those treated with paricalcitol. bPP and cPP decreased in all groups treated with native and active vitD. No significant changes in bPP and cPP were observed in the control group.Vpc-f did not change significantly in any of the groups, although the variation was quantitatively greater in group 3 (11.2±2 vs. 10.7±1.6 (p:0.06)). No differences were observed in the changes in Vpc-f between the groups when adjusted to the baseline values ​​of estimated glomerular filtration rate (eGFR), albuminuria, PTH, vitD, brachial and central blood pressure parameters, and their changes with treatment.Those who received treatment with native and active vitD presented a significant decrease in albuminuria of 17% (group 2) and 21% (group 3) compared to a 16% increase in the untreated group (group 1) (p:0 .01). A decrease in albuminuria ≥30% was observed more frequently in the groups treated with some form of vitD (group 2: 23%; group 3: 45%) than in the control group (13%) (p:0.03). The decrease in albuminuria observed in the groups treated with any of the forms of vitD did not vary when the baseline values ​​of the biochemical parameters of phosphorus-calcium metabolism, those of arterial function (PPb, PPc, Vpc-f) or its modifications were introduced as covariates. There was no significant correlation between changes in Vpc-f and albuminuria. In logistic regression, changes in arterial function parameters were also not explanatory for the ≥30% decrease in albuminuria. ConclusionsIn patients with CKD stages 3–4, treated with RAS blockers and with residual albuminuria, the administration of or paricalcitol reduces brachial and aortic pulse pressures, and albuminuria. The decrease in albuminuria does not seem to be mediated, at least not decisively, by changes in central hemodynamics or aortic stiffness.

Vitamin E and Metabolic Health: Relevance of Interactions with Other Micronutrients.

A hundred years have passed since vitamin E was identified as an essential micronutrient for mammals. Since then, many biological functions of vitamin E have been unraveled in both cell and animal models, including antioxidant and anti-inflammatory properties, as well as regulatory activities on cell signaling and gene expression. However, the bioavailability and physiological functions of vitamin E have been considerably shown to depend on lifestyle, genetic factors, and individual health conditions. Another important facet that has been considered less so far is the endogenous interaction with other nutrients. Accumulating evidence indicates that the interaction between vitamin E and other nutrients, especially those that are enriched by supplementation in humans, may explain at least some of the discrepancies observed in clinical trials. Meanwhile, increasing evidence suggests that the different forms of vitamin E metabolites and derivates also exhibit physiological activities, which are more potent and mediated via different pathways compared to the respective vitamin E precursors. In this review, possible molecular mechanisms between vitamin E and other nutritional factors are discussed and their potential impact on physiological and pathophysiological processes is evaluated using published co-supplementation studies.

Cathelicidin Mediates an Anti-Inflammatory Role of Active Vitamin D (Calcitriol) During M. paratuberculosis Infection

Vitamin D is a key regulator in calcium and phosphorus metabolism which are essential for maintaining bone health. Recent reports also showed a role for vitamin D in immune regulation which may be linked to vitamin D deficiency in autoimmune disorders including inflammatory diseases and Crohn’s disease (CD). This study examines the role of vitamin D deficiency in the regulation of Cathelicidin Antimicrobial Peptide (CAMP) in CD-like macrophages. The latter includes macrophages infected with Mycobacterium avium subsp. paratuberculosis (MAP) isolated from CD patient. Initially, we measured cathelicidin and calcitriol in ex vivo plasma samples from CD patients with or without MAP infection (N=40 per group). We also measured the expression and production of CAMP/LL-37, TNF-α, IL-1β, IL-10, cellular oxidative stress markers, and bacterial viability following treatment of MAP-infected macrophages with four different forms of vitamin D (D2, D3, calcifediol, and calcitriol). From these studies, we determined that LL-37 and calcitriol were significantly lower in CD samples from MAP-positive patients [155.55 ± 49.77 ng/mL and 51.48 ± 31.04 pg/mL, respectively] compared to MAP-negative patients [193.01 ± 78.95 ng/mL and 272.36 ± 94.77 pg/mL, respectively]. Moreover, calcitriol and calcifediol upregulated CAMP expression by nearly 5-fold and 3-fold, respectively. However, following MAP infection, only calcitriol increased CAMP by 3-folds. Both calcitriol and LL-37 reduced intracellular MAP viability by ~3 folds and inhibited TNF-α and IL-1β expression and production in these cells. Treating co-culture of Caco-2 monolayers and MAP-infected macrophages with LL-37 or calcitriol have shown a reduction in NOX-1 expression and DHE signal, in addition to a higher NADPH/NADPt ratio. Notably, calcitriol’s anti-inflammatory effects were lost upon CAMP knockdown by CAMP-siRNA transfection. Altogether, the data indicate that MAP infection and burden is significant in CD by disrupting the conversion of calcifediol to calcitriol and downregulation of CAMP expression leading to vitamin D deficiency.

Vitamin D and COVID-19: how close are they? (Аnalytical review of the literature)

The analytical review includes an analysis of current literature on the possible effects of vitamin D on the immune system functioning (innate and acquired immunity), as well as its impact on the risk of infectious diseases of the upper respiratory tract (IDURT) and COVID-19. Available clinical trial data evaluated in current meta-analyzes on the effects of vitamin D on the risk and course of COVID-19 and related hospitalization, mortality, and disease recovery rates were analyzed. Despite conflicting data on the positive effects of vitamin D on the IDURT risk in general and COVID-19 particularly, most clinical studies and meta-analyzes demonstrated this positive effect, pointing to certain limitations associated with heterogeneity of study populations, doses and forms of vitamin D etc. Current researches show the same bioequivalence of different forms of vitamin D (capsules, drops, tablets) in terms of their quality production and the need to correct vitamin D deficiency and deficiency in order to prevent IDURT in general and COVID-19 disease in particular.

Different forms of vitamin E and metabolite 13’-carboxychromanols inhibit cyclooxygenase-1 and its catalyzed thromboxane in platelets, and tocotrienols and 13’-carboxychromanols are competitive inhibitors of 5-lipoxygenase

Cyclooxygenase (COX-1 and COX-2)- and 5-lipoxygenase (5-LOX)-catalyzed biosynthesis of eicosanoids play important roles in inflammation and chronic diseases. The vitamin E family has four tocopherols and tocotrienols. We have shown that the metabolites of δ-tocopherol (δT) and δ-tocotrienol (δTE), i.e., δT-13’-carboxychromanol (COOH) and δTE-13’-COOH, respectively, inhibit COX-1/-2 and 5-LOX activity, but the nature of how they inhibit 5-LOX is not clear. Further, the impact of tocopherols and tocotrienols on COX-1/-2 or 5-LOX activity has not been fully delineated. In this study, we found that tocopherols and tocotrienols inhibited human recombinant COX-1 with IC50s of 1–12 µM, and suppressed COX-1-mediated formation of thromboxane in collagen-stimulated rat's platelets with IC50s of 8–50 µM. None of the vitamin E forms directly inhibited COX-2 activity. 13’-COOHs inhibited COX-1 and COX-2 enzyme activity with IC50s of 3–4 and 4–10 µM, respectively, blocked thromboxane formation in collagen- and ionophore-stimulated rats’ platelets with IC50s of 1.5-2.5 µM, and also inhibited COX-2-mediated prostaglandins in stimulated cells. Using enzyme kinetics, we observed that δT-13’-COOH, δTE-13’-COOH and δTE competitively inhibited 5-LOX activity with Ki of 1.6, 0.8 and 2.2 µM, respectively. These compounds decreased leukotriene B4 from stimulated neutrophil-like cells without affecting translocation of 5-LOX from cytosol to the nucleus. Our study reveals inhibitory effects of vitamin E forms and 13’-COOHs on COX-1 activity and thromboxane formation in platelets, and elucidates mechanisms underlying their inhibition of 5-LOX. These observations are useful for understanding the role of these compounds in disease prevention and therapy.

Vitamin K - sources, physiological role, kinetics, deficiency, detection, therapeutic use, and toxicity.

Vitamin K is traditionally connected with blood coagulation, since it is needed for the posttranslational modification of 7 proteins involved in this cascade. However, it is also involved in the maturation of another 11 or 12 proteins that play different roles, encompassing in particular the modulation of the calcification of connective tissues. Since this process is physiologically needed in bones, but is pathological in arteries, a great deal of research has been devoted to finding a possible link between vitamin K and the prevention of osteoporosis and cardiovascular diseases. Unfortunately, the current knowledge does not allow us to make a decisive conclusion about such a link. One possible explanation for this is the diversity of the biological activity of vitamin K, which is not a single compound but a general term covering natural plant and animal forms of vitamin K (K1 and K2) as well as their synthetic congeners (K3 and K4). Vitamin K1 (phylloquinone) is found in several vegetables. Menaquinones (MK4–MK13, a series of compounds known as vitamin K2) are mostly of a bacterial origin and are introduced into the human diet mainly through fermented cheeses. Current knowledge about the kinetics of different forms of vitamin K, their detection, and their toxicity are discussed in this review.

Vitamin D Supplementation for Patients with Chronic Kidney Disease: A Systematic Review and Meta-analyses of Trials Investigating the Response to Supplementation and an Overview of Guidelines

A large proportion of patients with chronic kidney disease (CKD) are vitamin D deficient (plasma 25-hydroxyvitamin D (25(OH)D) < 25 or 30 nmol/L per UK and US population guidelines) and this contributes to the development of CKD–mineral bone disease (CKD–MBD). Gaps in the evidence-base for the management of vitamin D status in relation to CKD–MBD are hindering the formulation of comprehensive guidelines. We conducted a systemic review of 22 RCTs with different forms of vitamin D or analogues with CKD–MBD related outcomes and meta-analyses for parathyroid hormone (PTH). We provide a comprehensive overview of current guidelines for the management of vitamin D status for pre-dialysis CKD patients. Vitamin D supplementation had an inconsistent effect on PTH concentrations and meta-analysis showed non- significant reduction (P = 0.08) whereas calcifediol, calcitriol and paricalcitol consistently reduced PTH. An increase in Fibroblast Growth Factor 23 (FGF23) with analogue administration was found in all 3 studies reporting FGF23, but was unaltered in 4 studies with vitamin D or calcifediol. Few RCTS reported markers of bone metabolism and variations in the range of markers prevented direct comparisons. Guidelines for CKD stages G1–G3a follow general population recommendations. For the correction of deficiency general or CKD-specific patient guidelines provide recommendations. Calcitriol or analogues administration is restricted to stages G3b–G5 and depends on patient characteristics. In conclusion, the effect of vitamin D supplementation in CKD patients was inconsistent between studies. Calcifediol and analogues consistently suppressed PTH, but the increase in FGF23 with calcitriol analogues warrants caution.