RESUMO
Sufficient vitamin D status is crucial for successful pregnancy and fetal development. The assessment of 25-hydroxyvitamin D (25(OH)D) concentrations is commonly used to evaluate vitamin D status. Our objective was to examine the interrelated biodynamics of maternal and neonatal total, free and bioavailable 25(OH)D in maternal-neonatal dyads at birth and their associations with homeostasis and neonatal birth anthropometry. We analysed a cohort of seventy full-term mother-child pairs. We found positive associations between all neonatal measures of vitamin D status. Maternal forms exhibited a similar pattern of association, except for the bioavailable maternal form. In multivariate analysis, both total and free maternal 25(OH)D concentrations were correlated with all neonatal forms (neonatal total 25(OH)D: 1·29 (95 % CI, 1·12, 1·46) for maternal total 25(OH)D, 10·89 (8·16, 13·63) for maternal free 25(OH)D), (neonatal free 25(OH)D: 0·15 for maternal total 25(OH)D, 1·28 (95 % CI, 0·89, 1·68) for maternal free 25(OH)D) and (0·13 (95 % CI, 0·10, 0·16), 1·06 (95 % CI, 0·68, 1·43) for maternal free 25(OH)D), respectively, with the exclusion of the bioavailable maternal form. We observed no significant interactions within or between groups regarding maternal and neonatal vitamin D parameters and maternal calcium and parathyroid hormone concentrations, and neonatal birth anthropometry. Our study indicates that bioavailable maternal and neonatal 25(OH)D have no significant effects on vitamin D equilibrium, Ca homeostasis and neonatal anthropometry at birth. However, we observed an interaction between maternal and neonatal total and free 25(OH)D concentrations at the maternal-neonatal interface, with no associations observed with other calciotropic or anthropometric outcomes.
Assuntos
Cálcio , Deficiência de Vitamina D , Vitamina D/análogos & derivados , Gravidez , Recém-Nascido , Feminino , Humanos , Calcifediol , Vitaminas , Cálcio da Dieta , Antropometria , Relações Mãe-FilhoRESUMO
Traditionally recognized as an RNA splicing regulator, heterogeneous nuclear ribonucleoprotein C1/C2 (hnRNPC1/C2) can also bind to double-stranded DNA and function in trans as a vitamin D response element (VDRE)-binding protein. As such, hnRNPC1/C2 may couple transcription induced by the active form of vitamin D, 1,25-dihydroxyvitamin D (1,25(OH)2D) with subsequent RNA splicing. In MG63 osteoblastic cells, increased expression of the 1,25(OH)2D target gene CYP24A1 involved immunoprecipitation of hnRNPC1/C2 with CYP24A1 chromatin and RNA. Knockdown of hnRNPC1/C2 suppressed expression of CYP24A1, but also increased expression of an exon 10-skipped CYP24A1 splice variant; in a minigene model the latter was attenuated by a functional VDRE in the CYP24A1 promoter. In genome-wide analyses, knockdown of hnRNPC1/C2 resulted in 3500 differentially expressed genes and 2232 differentially spliced genes, with significant commonality between groups. 1,25(OH)2D induced 324 differentially expressed genes, with 187 also observed following hnRNPC1/C2 knockdown, and a further 168 unique to hnRNPC1/C2 knockdown. However, 1,25(OH)2D induced only 10 differentially spliced genes, with no overlap with differentially expressed genes. These data indicate that hnRNPC1/C2 binds to both DNA and RNA and influences both gene expression and RNA splicing, but these actions do not appear to be linked through 1,25(OH)2D-mediated induction of transcription.
Assuntos
Ribonucleoproteínas Nucleares Heterogêneas Grupo C/metabolismo , Osteócitos/metabolismo , Splicing de RNA , Transcrição Gênica , Vitamina D/metabolismo , Processamento Alternativo , Linhagem Celular Tumoral , Análise por Conglomerados , Perfilação da Expressão Gênica , Regulação da Expressão Gênica , Técnicas de Silenciamento de Genes , Ribonucleoproteínas Nucleares Heterogêneas Grupo C/genética , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Osteócitos/efeitos dos fármacos , Regiões Promotoras Genéticas , Ligação Proteica , Interferência de RNA , Precursores de RNA , Vitamina D3 24-Hidroxilase/genética , Vitamina D3 24-Hidroxilase/metabolismoRESUMO
The antibacterial protein hepcidin regulates the absorption, tissue distribution, and extracellular concentration of iron by suppressing ferroportin-mediated export of cellular iron. In CKD, elevated hepcidin and vitamin D deficiency are associated with anemia. Therefore, we explored a possible role for vitamin D in iron homeostasis. Treatment of cultured hepatocytes or monocytes with prohormone 25-hydroxyvitamin D or active 1,25-dihydroxyvitamin D decreased expression of hepcidin mRNA by 0.5-fold, contrasting the stimulatory effect of 25-hydroxyvitamin D or 1,25-dihydroxyvitamin D on related antibacterial proteins such as cathelicidin. Promoter-reporter and chromatin immunoprecipitation analyses indicated that direct transcriptional suppression of hepcidin gene (HAMP) expression mediated by 1,25-dihydroxyvitamin D binding to the vitamin D receptor caused the decrease in hepcidin mRNA levels. Suppression of HAMP expression was associated with a concomitant increase in expression of the cellular target for hepcidin, ferroportin protein, and decreased expression of the intracellular iron marker ferritin. In a pilot study with healthy volunteers, supplementation with a single oral dose of vitamin D (100,000 IU vitamin D2) increased serum levels of 25D-hydroxyvitamin D from 27±2 ng/ml before supplementation to 44±3 ng/ml after supplementation (P<0.001). This response was associated with a 34% decrease in circulating levels of hepcidin within 24 hours of vitamin D supplementation (P<0.05). These data show that vitamin D is a potent regulator of the hepcidin-ferroportin axis in humans and highlight a potential new strategy for the management of anemia in patients with low vitamin D and/or CKD.
Assuntos
Peptídeos Catiônicos Antimicrobianos/metabolismo , Hepcidinas/metabolismo , Vitamina D/fisiologia , Células 3T3 , Adulto , Animais , Proteínas de Transporte de Cátions/metabolismo , Feminino , Ferritinas/metabolismo , Voluntários Saudáveis , Células Hep G2 , Humanos , Masculino , Camundongos , Pessoa de Meia-Idade , Projetos Piloto , CatelicidinasRESUMO
Activation of precursor 25-hydroxyvitamin D3 (25D) to hormonal 1,25-dihydroxyvitamin D3 (1,25D) is a pivotal step in vitamin D physiology, catalysed by the enzyme 25-hydroxyvitamin D-1α-hydroxylase (1α-hydroxylase). To establish new models for assessing the physiological importance of the 1α-hydroxylase-25D-axis, we used Danio rerio (zebrafish) to characterize expression and biological activity of the gene for 1α-hydroxylase (cyp27b1). Treatment of day 5 zebrafish larvae with inactive 25D (5-150 nM) or active 1,25D (0.1-10 nM) induced dose responsive expression (15-95-fold) of the vitamin D-target gene cyp24a1 relative to larvae treated with vehicle, suggesting the presence of Cyp27b1 activity. A full-length zebrafish cyp27b1 cDNA was then generated using RACE and RT-PCR methods. Sequencing of the resulting clone revealed an open reading frame encoding a protein of 505 amino acids with 54% identity to human CYP27B1. Transfection of a cyp27b1 expression vector into HKC-8, a human kidney proximal tubular epithelial cell line, enhanced intracrine metabolism of 25D to 1,25D resulting in greater than twofold induction of CYP24A1 mRNA expression and a 25-fold increase in 1,25D production compared to empty vector. These data indicate that we have cloned a functional zebrafish CYP27B1, representing a phylogenetically distant branch from mammals of this key enzyme in vitamin D metabolism. Further analysis of cyp27b1 expression and activity in zebrafish may provide new perspectives on the biological importance of 25D metabolism.
Assuntos
Clonagem Molecular , Vitamina D3 24-Hidroxilase/genética , Vitamina D/análogos & derivados , Peixe-Zebra , Animais , Linhagem Celular , Perfilação da Expressão Gênica , Humanos , Rim/metabolismo , Modelos Animais , Miocárdio/metabolismo , Filogenia , Baço/metabolismo , Vitamina D/metabolismo , Vitamina D3 24-Hidroxilase/metabolismoRESUMO
Background: Apart from the well-established skeletal effects, vitamin D has been explored as a secretagogue influencing various adipokines, including adiponectin and irisin. Recent evidence suggests that specific forms of 25-Hydroxyvitamin D (25(OHD), such as free and bioavailable 25(OH)D, may provide more accurate measurements of vitamin D status. The relationship between vitamin D status and serum irisin and adiponectin concentrations remains largely unexplored, particularly during pregnancy. Methods: We analyzed data from 67 healthy maternal-neonatal pairs from Northern Greece at birth. Biochemical and hormonal tests were conducted on each maternal-neonatal pair. The vitamin D forms were estimated using validated mathematical models. Subsequently, regression analyses were conducted to determine the association between the vitamin D forms and adipokine levels. Results: Bioavailable maternal 25(OH)D was inversely associated with neonatal irisin concentrations [ß=-73.46 (-140.573 to -6.341), p=0.034]. No other associations were observed between maternal vitamin D status and neonatal adipokine concentrations. Conclusion: In conclusion, maternal bioavailable vitamin D concentrations are inversely associated with neonatal serum irisin concentrations, warranting further studies to evaluate the underlying mechanisms for this finding.
Assuntos
Adiponectina , Fibronectinas , Vitamina D , Humanos , Fibronectinas/sangue , Feminino , Vitamina D/sangue , Vitamina D/análogos & derivados , Adiponectina/sangue , Grécia , Gravidez , Recém-Nascido , Adulto , MasculinoRESUMO
The serum vitamin D binding protein (DBP), also known as GC-globulin, is a multifunctional protein known for its role in the transport of vitamin D metabolites. DBP also binds fatty acids and actin monomers, preventing their polymerization that could be detrimental in the circulatory system. DBP may have immune functions independent of its role as a transporter of vitamin D. Because of the abundance of DBP, many aspects of its basic biochemistry were quickly established. Other features of vitamin D action, particularly transcriptional mechanisms of regulation, received greater focus and early interest in DBP centred on its value as a tool for population genetics because of its intriguing genetic variations. Nonetheless, knowledge of DBP mechanisms in physiology was obtained, and functions beyond vitamin D ligand binding were identified. With the recent increased attention regarding the benefits of vitamin D (bone health and immunological regulation), there has been a resurgence of interest in DBP. Because DBP is the primary transporter of vitamin D, it has a role in maintaining the total levels of vitamin D for the organism and in regulating the amounts of free (unbound) vitamin D available for specific tissues and cell types to utilize. This review will describe the findings on the basic biochemistry and molecular biology of DBP, the studies that elucidated its biological functions and highlight these results in light of the current renewed interest in vitamin D and human health, as well as the debate over what constitutes sufficient levels of vitamin D.
Assuntos
Proteína de Ligação a Vitamina D , Animais , Variação Genética/genética , Humanos , Vitamina D/imunologia , Vitamina D/metabolismo , Proteína de Ligação a Vitamina D/genética , Proteína de Ligação a Vitamina D/imunologia , Proteína de Ligação a Vitamina D/metabolismoRESUMO
BACKGROUND: Vitamin D deficiency has been associated with worse coronavirus disease 2019 (COVID-19) outcomes, but circulating 25-hydroxyvitamin D [25(OH)D] is largely bound to vitamin D-binding protein (DBP) or albumin, both of which tend to fall in illness, making the 25(OH)D status hard to interpret. Because of this, measurements of unbound ("free") and albumin-bound ("bioavailable") 25(OH)D have been proposed. OBJECTIVES: We aimed to examine the relationship between vitamin D status and mortality from COVID-19. METHODS: In this observational study conducted in Liverpool, UK, hospitalized COVID-19 patients with surplus sera available for 25(OH)D analysis were studied. Clinical data, including age, ethnicity, and comorbidities, were extracted from case notes. Serum 25(OH)D, DBP, and albumin concentrations were measured. Free and bioavailable 25(OH)D were calculated. Relationships between total, free, and bioavailable 25(OH)D and 28-day mortality were analyzed by logistic regression. RESULTS: There were 472 patients with COVID-19 included, of whom 112 (23.7%) died within 28 days. Nonsurvivors were older (mean age, 73 years; range, 34-98 years) than survivors (mean age, 65 years; range, 19-95 years; P = 0.003) and were more likely to be male (67%; P = 0.02). The frequency of vitamin D deficiency [25(OH)D < 50 nmol/L] was similar between nonsurvivors (71/112; 63.4%) and survivors (204/360; 56.7%; P = 0.15) but, after adjustments for age, sex, and comorbidities, increased odds for mortality were present in those with severe deficiency [25(OH)D < 25 nmol/L: OR, 2.37; 95% CI, 1.17-4.78] or a high 25(OH)D (≥100 nmol/L; OR, 4.65; 95% CI, 1.51-14.34) compared with a 25(OH)D value of 50-74 nmol/L (reference). Serum DBP levels were not associated with mortality after adjustments for 25(OH)D, age, sex, and comorbidities. Neither free nor bioavailable 25(OH)D values were associated with mortality. CONCLUSIONS: Vitamin D deficiency, as commonly defined by serum 25(OH)D levels (<50 nmol/L), is not associated with increased mortality from COVID-19, but extremely low (<25 nmol/L) and high (>100 nmol/L) levels may be associated with mortality risks. Neither free nor bioavailable 25(OH)D values are associated with mortality risk. The study protocol was approved by the London-Surrey Research Ethics Committee (20/HRA/2282).
Assuntos
COVID-19 , Deficiência de Vitamina D , Idoso , Albuminas/metabolismo , Feminino , Humanos , Masculino , Vitamina D , Deficiência de Vitamina D/complicações , Proteína de Ligação a Vitamina D , VitaminasRESUMO
The active form of vitamin D, 1,25-dihydroxyvitamin D (1,25(OH)(2)D) enhances innate immunity by inducing the cathelicidin antimicrobial peptide (hCAP). In monocytes/macrophages, this occurs primarily in response to activation of TLR, that induce expression of the vitamin D receptor and localized synthesis of 1,25(OH)(2)D from precursor 25-hydroxyvitamin D(3) (25OHD). To clarify the relationship between vitamin D and innate immunity, we assessed changes in hCAP expression in vivo and ex vivo in human subjects attending a bone clinic (n = 50). Of these, 38% were vitamin D-insufficient (<75 nM 25OHD) and received supplementation with vitamin D (50,000 IU vitamin D(2) twice weekly for 5 wk). Baseline 25OHD status or vitamin D supplementation had no effect on circulating levels of hCAP. Therefore, ex vivo changes in hCAP for each subject were assessed using peripheral blood monocytes cultured with 10% autologous serum (n = 28). Under these vitamin D "insufficient" conditions the TLR2/1 ligand 19 kDa lipopeptide or the TLR4 ligand LPS, monocytes showed increased expression of the vitamin D-activating enzyme CYP27b1 (5- and 5.5-fold, respectively, both p < 0.01) but decreased expression of hCAP mRNA (10-fold and 30-fold, both p < 0.001). Following treatment with 19 kDa, expression of hCAP: 1) correlated with 25OHD levels in serum culture supplements (R = 0.649, p < 0.001); 2) was significantly enhanced by exogenous 25OHD (5 nM); and 3) was significantly enhanced with serum from vivo vitamin D-supplemented patients. These data suggest that a key role of vitamin D in innate immunity is to maintain localized production of antibacterial hCAP following TLR activation of monocytes.
Assuntos
Peptídeos Catiônicos Antimicrobianos/imunologia , Imunidade Inata , Monócitos/imunologia , Deficiência de Vitamina D/imunologia , Vitamina D/análogos & derivados , 25-Hidroxivitamina D3 1-alfa-Hidroxilase/biossíntese , 25-Hidroxivitamina D3 1-alfa-Hidroxilase/imunologia , Peptídeos Catiônicos Antimicrobianos/metabolismo , Catelicidinas , Células Cultivadas , Ensaio de Imunoadsorção Enzimática , Feminino , Expressão Gênica , Humanos , Masculino , Pessoa de Meia-Idade , Monócitos/metabolismo , RNA Mensageiro/análise , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Receptor 1 Toll-Like/imunologia , Receptor 1 Toll-Like/metabolismo , Receptor 2 Toll-Like/imunologia , Receptor 2 Toll-Like/metabolismo , Receptor 4 Toll-Like/imunologia , Receptor 4 Toll-Like/metabolismo , Vitamina D/imunologia , Vitamina D/metabolismo , Vitamina D/uso terapêutico , Deficiência de Vitamina D/metabolismoRESUMO
Vitamin D has a long-established role in bone health. In the last two decades, there has been a dramatic resurgence in research interest in vitamin D due to studies that have shown its possible benefits for non-skeletal health. Underpinning the renewed interest in vitamin D was the identification of the vital role of intracrine or localized, tissue-specific, conversion of inactive pro-hormone 25-hydroxyvitamin D [25(OH)D] to active 1,25-dihydroxyvitamin D [1,25(OH)2D]. This intracrine mechanism is the likely driving force behind vitamin D action resulting in positive effects on human health. To fully capture the effect of this localized, tissue-specific conversion to 1,25(OH)2D, adequate 25(OH)D would be required. As such, low serum concentrations of 25(OH)D would compromise intracrine generation of 1,25(OH)2D within target tissues. Consistent with this is the observation that all adverse human health consequences of vitamin D deficiency are associated with a low serum 25(OH)D level and not with low 1,25(OH)2D concentrations. Thus, clinical investigators have sought to define what concentration of serum 25(OH)D constitutes adequate vitamin D status. However, since 25(OH)D is transported in serum bound primarily to vitamin D binding protein (DBP) and secondarily to albumin, is the total 25(OH)D (bound plus free) or the unbound free 25(OH)D the crucial determinant of the non-classical actions of vitamin D? While DBP-bound-25(OH)D is important for renal handling of 25(OH)D and endocrine synthesis of 1,25(OH)2D, how does DBP impact extra-renal synthesis of 1,25(OH)2D and subsequent 1,25(OH)2D actions? Are their pathophysiological contexts where total 25(OH)D and free 25(OH)D would diverge in value as a marker of vitamin D status? This review aims to introduce and discuss the concept of free 25(OH)D, the molecular biology and biochemistry of vitamin D and DBP that provides the context for free 25(OH)D, and surveys in vitro, animal, and human studies taking free 25(OH)D into consideration.
RESUMO
Vitamin D-deficiency has been linked to inflammatory diseases including rheumatoid arthritis (RA). Studies to date have focused on the impact of serum 25-hydroxyvitamin D3 (25(OH)D3), an inactive form of vitamin D, on RA disease activity and progression. However, anti-inflammatory actions of vitamin D are likely to be mediated at sites of RA disease, namely the inflamed joint, and may involve other vitamin D metabolites notably the active form of vitamin D, 1,25-dihydroxyvitamin D3 (1,25(OH)2D3). In the current study serum and synovial fluid samples from n = 20 patients with persistent RA and n = 7 patients with reactive arthritis (ReA) were analysed for multiple vitamin D metabolites. Serum data for RA and ReA patients were compared to healthy controls (HC). There was no significant difference between RA or ReA patients relative to HC for 25(OH)D3, 24,25(OH)2D3, 1,25(OH)2D3 or 25(OH)D2. However, 3-epi-25(OH)D3 was significantly lower in RA and ReA patients compared to HC (p < 0.05). All vitamin D metabolites, apart from 25(OH)D2, were lower in SF compared to serum, and SF 1,25(OH)2D3 was unquantifiable in 13/20 RA and 4/7 ReA samples. SF 25(OH)D3, 3-epi-25(OH)D3 and DBP correlated inversely with swollen joint score, and serum 25(OH)D2 and SF DBP correlated directly with C-reactive protein levels. These data indicate that serum 25(OH)D3 provides only limited insight into the role of vitamin D in RA. Alternative serum metabolites such as 3-epi-25(OH)2D3, and SF metabolites, notably lack of SF 1,25(OH)2D3, may be more closely linked to RA disease severity and progress.
Assuntos
24,25-Di-Hidroxivitamina D 3/sangue , Artrite Reumatoide/sangue , Deficiência de Vitaminas/sangue , Calcifediol/sangue , Calcitriol/sangue , Líquido Sinovial/química , 24,25-Di-Hidroxivitamina D 3/análise , Adulto , Idoso , Idoso de 80 Anos ou mais , Calcifediol/análise , Calcitriol/análise , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Proibitinas , Adulto JovemRESUMO
The active form of vitamin D, 1,25-dihydroxyvitamin D3, [1,25(OH)2D3] has potent actions on innate and adaptive immunity. Although endocrine synthesis of 1,25(OH)2D3 takes place in the kidney, the enzyme that catalyzes this, 25-hydroxyvitamin D-1alpha-hydroxylase (CYP27b1 in humans, Cyp27b1 in mice), is expressed at many extra-renal sites including the colon. We have shown previously that colonic expression of CYP27b1 may act to protect against the onset of colitis. To investigate this further, we firstly characterized changes in Cyp27b1 expression in a mouse model of colitis. Mice treated with dextran sodium sulfate (DSS) showed weight loss, histological evidence of colitis, and increased expression of inflammatory cytokines. This was associated with decreased renal expression of Cyp27b1 (5-fold, P=0.013) and lower serum 1,25(OH)2D3 (51.8+/-5.9 pg/nl vs. 65.1+/-1.6 in controls, P<0.001). However, expression of CYP27b1 was increased in the proximal colon of DSS mice (4-fold compared with controls, P<0.001). Further studies were carried out using Cyp27b1 null (-/-) mice. Compared with+/-controls the Cyp27b1-/-mice showed increased weight loss (4.9% vs. 22.8%, P<0.001) and colitis. This was associated with raised IL-1 in the distal colon and IL-17 in the proximal and distal colon. Conversely, DSS-treated Cyp27b1-/-mice exhibited lower IL-10 in the proximal colon and toll-like receptors 2 and 4 in the distal colon. These data indicate that both local and endocrine synthesis of 1,25(OH)2D3 affect colitis in DSS-treated mice. Lack of Cyp27b1 exacerbates disease in this model, suggesting that similar effects may occur with vitamin D deficiency.
Assuntos
25-Hidroxivitamina D3 1-alfa-Hidroxilase/genética , Calcitriol/sangue , Colite/metabolismo , Sistema Endócrino/metabolismo , Gastroenterite/metabolismo , Deficiência de Vitamina D/metabolismo , Animais , Comunicação Autócrina/fisiologia , Colite/induzido quimicamente , Colite/imunologia , Colo/enzimologia , Colo/imunologia , Citocinas/genética , Citocinas/imunologia , Sulfato de Dextrana/toxicidade , Modelos Animais de Doenças , Sistema Endócrino/imunologia , Gastroenterite/induzido quimicamente , Gastroenterite/imunologia , Expressão Gênica/imunologia , Homeostase/fisiologia , Rim/enzimologia , Rim/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , RNA Mensageiro/metabolismo , Receptores de Calcitriol/genética , Receptor 2 Toll-Like/genética , Receptor 2 Toll-Like/imunologia , Receptor 4 Toll-Like/genética , Receptor 4 Toll-Like/imunologia , Deficiência de Vitamina D/imunologiaRESUMO
To investigate an immunomodulatory role for vitamin D in pregnancy we used mice raised on vitamin D-sufficient (SUFF), or -deficient (DEF) diets. At embryonic day 14, pregnant mice received intraperitoneal injection of lipopolysaccharide (LPS) or vehicle for 24h, with age-matched non-pregnant mice as controls. In non-pregnant mice, 6 serum analytes (IL-1ß, IL-18, MDC/CCL22, MIP-1α/CCL3, EGF, IgA) were lower in DEF mice. In pregnant DEF mice only GH was higher. In non-pregnant mice LPS induced 28 analytes, with 5 (IL-18, IP-10/CXCL10, MCP-1/CCL2, MIP-1ß/CCL4, MIP-3ß/CCL19) being highest in DEF mice. In pregnant SUFF mice 16 serum analytes increased with LPS, and 6 of these (IP-10/CXCL10, MCP-1/CCL2, SAP, TIMP-1, VCAM-1, vWF) were higher and 1 (GCP-2/CXCL6) lower in DEF mice. Parallel analysis of placental mRNAs showed elevated mRNA for Il-6, Ccl2 and Cxcl10 in placentae from male and female fetuses in LPS-DEF mice. However, LPS-induced expression of Ifnγ, Tnfα, and Cxcl6 was only observed in female placentae from DEF mice. LPS-DEF mice also showed smaller litter sizes relative to control SUFF mice. Numbers of female fetuses per dam were significantly lower for DEF mice with or without LPS challenge. LPS had no effect on numbers of male fetuses from DEF mothers, but significantly decreased male fetuses from SUFF mothers. These data indicate that vitamin D is an important component of anti-inflammatory immune responses during pregnancy, with the placenta and fetal sex playing pivotal roles in this process.
Assuntos
Inflamação/metabolismo , Placenta/metabolismo , Deficiência de Vitamina D/metabolismo , 25-Hidroxivitamina D3 1-alfa-Hidroxilase/genética , Animais , Citocinas/genética , Feminino , Feto/metabolismo , Lipopolissacarídeos/farmacologia , Tamanho da Ninhada de Vivíparos , Masculino , Camundongos Endogâmicos C57BL , Gravidez , RNA Mensageiro/metabolismo , Receptores de Calcitriol/genética , Caracteres Sexuais , Vitamina D3 24-Hidroxilase/genéticaRESUMO
Context: The physiologic role of free 25-hydroxyvitamin D [25(OH)D] in humans is unclear. Objective: To assess whether rise in total vs free 25(OH)D is associated with change in downstream biomarkers of 25(OH)D entry into target cells in kidney and parathyroid: 24,25-dihyroxyvitamin D [24,25(OH)2D] and PTH, respectively. Design: 16-week randomized controlled trial. Intervention: 60 µg (2400 IU)/d of D3 or 20 µg/d of 25(OH)D3. Setting: Academic medical center. Participants: 35 adults age ≥18 years with 25(OH)D levels < 20 ng/mL. Main Outcome Measures: 24,25(OH)2D, 1,25-dihyroxyvitamin D [1,25(OH)2D] and PTH. Results: At baseline, participants [D3 and 25(OH)D3 groups combined] were 35.1 ± 10.6 years. Mean total 25(OH)D, free 25(OH)D, 24,25(OH)2D, and PTH were 16.6 ng/mL, 4.6 pg/mL, 1.3 ng/mL, and 37.2 pg/mL, respectively. From 0 to 4 weeks, rise in only free 25(OH)D was associated with a concurrent 24,25(OH)2D increase [P = 0.03, adjusted for change in 1,25(OH)2D and supplementation regimen] and PTH decrease (P = 0.01, adjusted for change in calcium and supplementation regimen). Between 4 and 8 weeks, and again from 8 to 16 weeks, rises in free and total 25(OH)D were associated with 24,25(OH)2D increase; in contrast, rise in neither total nor free 25(OH)D was associated with PTH decrease during these time periods. Conclusions: Early rise in free 25(OH)D during treatment of vitamin D deficiency was more strongly associated with changes in biomarkers of 25(OH)D entry into target kidney and parathyroid cells, suggesting a physiologic role of free 25(OH)D in humans.
Assuntos
Suplementos Nutricionais , Hormônio Paratireóideo/sangue , Deficiência de Vitamina D/sangue , Vitamina D/análogos & derivados , 24,25-Di-Hidroxivitamina D 3/administração & dosagem , Adulto , Biomarcadores/sangue , Calcifediol/sangue , Cálcio/administração & dosagem , Feminino , Humanos , Rim/metabolismo , Masculino , Glândulas Paratireoides/metabolismo , Fatores de Tempo , Vitamina D/sangue , Deficiência de Vitamina D/terapia , Vitaminas/administração & dosagemRESUMO
CONTEXT: Vitamin D deficiency disproportionately affects nonwhite individuals. Controversy persists over how to best restore low 25D levels, and how to best define vitamin D status [total (protein bound plus free) vs free 25D]. OBJECTIVE: To assess the effects of vitamin D3 (cholecalciferol, or D3) vs 25-hydroxyvitamin D3 (calcifediol, or 25D3) on total and free 25D in a multiethnic cohort of adults, and whether change in parathyroid hormone (PTH) is more strongly associated with total vs free 25D. DESIGN: Sixteen-week randomized controlled trial. Biochemistries at 0, 4, 8, and 16 weeks. SETTING: Academic medical center. PARTICIPANTS: Thirty-five adults ≥18 years of age with 25D levels <20 ng/mL. INTERVENTION: Sixty micrograms (2400 IU)/d of D3 or 20 µg/d of 25D3. MAIN OUTCOME MEASURES: Total and free 25D, and PTH. RESULTS: Baseline total (16.2 ± 3.7 vs 17.0 ± 2.5 ng/mL; P = 0.4) and free (4.2 ± 0.8 vs 4.7 ± 1.0 pg/mL; P = 0.2) 25D were similar between D3 and 25D3 groups, respectively; 25D3 increased total (+25.5 vs +13.8 ng/mL; P = 0.001) and free (+6.6 vs +3.5 pg/mL; P = 0.03) 25D more than D3. By 4 weeks, 87.5% of 25D3 participants had total 25D levels ≥30 ng/mL, compared with 23.1% of D3 participants (P = 0.001). Change in PTH was associated with both total (P = 0.01) and free 25D (P = 0.04). CONCLUSIONS: 25D3 increased total and free 25D levels more rapidly than D3, regardless of race/ethnicity. Free and total 25D were similarly associated with change in PTH.
Assuntos
Calcifediol/farmacologia , Colecalciferol/farmacologia , Hormônio Paratireóideo/sangue , Deficiência de Vitamina D/sangue , Vitamina D/análogos & derivados , Adulto , Calcifediol/uso terapêutico , Cálcio/sangue , Cálcio/urina , Colecalciferol/uso terapêutico , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Vitamina D/sangue , Deficiência de Vitamina D/tratamento farmacológico , Deficiência de Vitamina D/urina , Adulto JovemRESUMO
BACKGROUND: Despite recent advances, infection remains the most common etiology of arthroplasty failure. Recent work suggests that 25-hydroxyvitamin D (25D) deficiency correlates with the frequency of periprosthetic joint infection (PJI). We endeavored to examine whether 25D3 deficiency leads to increased bacterial burden in vivo in an established mouse model of PJI and, if so, whether this effect can be reversed by preoperative 25D3 supplementation. METHODS: Mice (lys-EGFP) possessing fluorescent neutrophils were fed a vitamin D3-sufficient (n = 20) or deficient (n = 40) diet for 6 weeks. A group of 25D3-deficient mice (n = 20) were "rescued" with 1 intraperitoneal dose of 25D3 at 3 days before surgery. A stainless steel implant was inserted into the knee joint and the joint space was inoculated with bioluminescent Staphylococcus aureus (1 × 10 colony forming units [CFUs]). In vivo imaging was used to monitor bacterial burden and neutrophil infiltration. Blood was drawn to confirm 25D3 levels 3 days before surgery and on postoperative days (PODs) 0 and 14. Mice were killed at POD 21, and CFUs were quantified after culture. Myeloperoxidase (MPO) and ß-N-acetylglucosaminidase (NAG) were assayed to look at neutrophil infiltration and activated tissue macrophage recruitment, respectively. RESULTS: Serum values confirmed 25D3 deficiency and repletion of the 25D3-rescued group. Bacterial bioluminescence and neutrophil fluorescence were significantly greater (p < 0.05) in the 25D3-deficient group. CFU counts from the joint tissue and implant were also significantly greater in this group (p < 0.05). Rescue treatment significantly decreased bacterial burden and neutrophil infiltration (p < 0.05). Compared with the 25D3-sufficient and 25D3-rescued groups, MPO activity was higher (p < 0.02) and NAG activity was lower (p < 0.03) in the 25D3-deficient group. CONCLUSIONS: This study demonstrated in vivo in a mouse model of PJI that (1) 25D3 deficiency results in increased bacterial burden and neutrophil infiltration, and (2) this effect can be reversed with preoperative repletion of 25D3. CLINICAL RELEVANCE: Considering that >65% of patients undergoing arthroplasty have insufficient or low levels of total 25D and that 25D levels can be replenished with ease using a U.S. Food and Drug Administration (FDA)-approved, oral 25D3 product, 25D deficiency may be an important modifiable risk factor in humans undergoing joint replacement.
Assuntos
Suplementos Nutricionais , Prótese do Joelho/efeitos adversos , Infecções Relacionadas à Prótese/prevenção & controle , Infecções Estafilocócicas/prevenção & controle , Deficiência de Vitamina D/tratamento farmacológico , Vitamina D/análogos & derivados , Vitaminas/uso terapêutico , Animais , Artroplastia do Joelho , Carga Bacteriana , Biomarcadores/sangue , Esquema de Medicação , Injeções Intraperitoneais , Masculino , Camundongos , Infiltração de Neutrófilos , Cuidados Pré-Operatórios/métodos , Infecções Relacionadas à Prótese/etiologia , Infecções Relacionadas à Prótese/microbiologia , Distribuição Aleatória , Fatores de Risco , Infecções Estafilocócicas/etiologia , Infecções Estafilocócicas/microbiologia , Vitamina D/sangue , Vitamina D/uso terapêutico , Deficiência de Vitamina D/complicações , Deficiência de Vitamina D/diagnóstico , Deficiência de Vitamina D/microbiologiaRESUMO
CONTEXT: Controversy persists over: 1) how best to restore low serum 25-hydroxyvitamin D (25D) levels (vitamin D2 [D2] vs vitamin D3 [D3]); 2) how best to define vitamin D status (total [protein-bound + free] vs free 25D); and 3) how best to assess the bioactivity of free 25D. OBJECTIVE: To assess: 1) the effects of D2 vs D3 on serum total and free 25D; and 2) whether change in intact PTH (iPTH) is more strongly associated with change in total vs free 25D. DESIGN: Participants previously enrolled in a D2 vs D3 trial were matched for age, body mass index, and race/ethnicity. Participants received 50 000 IU of D2 or D3 twice weekly for 5 weeks, followed by a 5-week equilibration period. Biochemical assessment was performed at baseline and at 10 weeks. SETTING AND PARTICIPANTS: Thirty-eight adults (19 D2 and 19 D3) ≥18 years of age with baseline 25D levels <30 ng/mL were recruited from an academic ambulatory osteoporosis clinic. OUTCOME MEASURES: Serum measures were total 25D, free 25D (directly measured), 1,25-dihydroxyvitamin D, calcium, and iPTH. Urine measure was fasting calcium:creatinine ratio. RESULTS: Baseline total (22.2 ± 3.3 vs 23.3 ± 7.2 ng/mL; P = .5) and free (5.4 ± 0.8 vs 5.3 ± 1.7 pg/mL; P = .8) 25D levels were similar between D2 and D3 groups. Increases in total (+27.6 vs +12.2 ng/mL; P = .001) and free (+3.6 vs +6.2 pg/mL; P = .02) 25D levels were greater with D3 vs D2. Percentage change in iPTH was significantly associated with change in free (but not total) 25D, without and with adjustment for supplementation regimen, change in 1,25-dihydroxyvitamin D, and change in calcium. CONCLUSIONS: D3 increased total and free 25D levels to a greater extent than D2. Free 25D may be superior to total 25D as a marker of vitamin D bioactivity.
Assuntos
Cálcio/sangue , Colecalciferol/administração & dosagem , Ergocalciferóis/administração & dosagem , Deficiência de Vitamina D/sangue , Deficiência de Vitamina D/tratamento farmacológico , Vitamina D/análogos & derivados , Adulto , Idoso , Biomarcadores/sangue , Estudos de Casos e Controles , Relação Dose-Resposta a Droga , Homeostase/efeitos dos fármacos , Terapia de Reposição Hormonal , Humanos , Pessoa de Meia-Idade , Hormônio Paratireóideo/sangue , Vitamina D/sangueRESUMO
25-Hydroxyvitamin D (25D) circulates bound primarily to serum vitamin D binding protein (DBP), with DBP showing higher binding affinity for 25D3 than 25D2. We therefore hypothesized that vitamin D2 (D2) promotes higher serum levels of unbound 25D (free 25D), with different functional responses, relative to vitamin D3 (D3). Week 3 C56BL/6 mice were placed on diets containing either D2 or D3 alone (both 1000 IU/kg). At week 8 and week 16, D2 mice had only 25D2 in circulation (26.6 ± 1.9 and 33.3 ± 4.4 ng/mL), and D3 mice had only 25D3 (28.3 ± 2.0 and 31.7 ± 2.1 ng/mL). At week 8 (44.5 ± 6.4 vs 62.4 ± 11.6 pg/mL, P < .05) and week 16 (78.4 ± 12.6 vs 95.5 ± 11.6), D2 mice had lower serum 1,25-dihydroxyvitamin D relative to D3 mice. By contrast, measured free 25D was significantly higher in D2 mice at week 8 (16.8 ± 0.65 vs 8.4 ± 0.63 pg/mL, P < .001) and week 16 (17.4 ± 0.43 vs 8.4 ± 0.44, P < .001). A two-way ANOVA of bone histomorphometry showed that week 8 D2 mice had significantly higher osteoclast surface/bone surface, eroded surface/bone surface, and mineral apposition rate compared with D3 mice. Osteoblast surface/bone surface was higher in week 8 D2 females but not week 8 D2 males. At week 16, D2 mice had significantly higher bone volume/total volume and trabecular number compared with D3 mice. Differences in bone phenotype were observed despite D2 mice reaching similar serum 25D levels and lower 1,25D levels compared with D3 mice. These data indicate that 25D2 binds less well to DBP than 25D3, with resulting higher levels of free 25D promoting differential effects on bone in mice exposed to D2 alone.
Assuntos
Colecalciferol/farmacocinética , Ergocalciferóis/farmacocinética , Vitamina D/análogos & derivados , Animais , Osso e Ossos/anatomia & histologia , Linhagem Celular , Feminino , Humanos , Rim/metabolismo , Masculino , Camundongos Endogâmicos C57BL , Baço/metabolismo , Vitamina D/sangueRESUMO
CONTEXT: Total 25-hydroxyvitamin D (25OHD) is a marker of vitamin D status and is lower in African Americans than in whites. Whether this difference holds for free 25OHOD (f25OHD) is unclear, considering reported genetic-racial differences in vitamin D binding protein (DBP) used to calculate f25OHD. OBJECTIVES: Our objective was to assess racial-geographic differences in f25OHD and to understand inconsistencies in racial associations with DBP and calculated f25OHD. DESIGN: This study used a cross-sectional design. SETTING: The general community in the United States, United Kingdom, and The Gambia were included in this study. PARTICIPANTS: Men in Osteoporotic Fractures in Men and Medical Research Council studies (N = 1057) were included. EXPOSURES: Total 25OHD concentration, race, and DBP (GC) genotype exposures were included. OUTCOME MEASURES: Directly measured f25OHD, DBP assessed by proteomics, monoclonal and polyclonal immunoassays, and calculated f25OHD were the outcome measures. RESULTS: Total 25OHD correlated strongly with directly measured f25OHD (Spearman r = 0.84). Measured by monoclonal assay, mean DBP in African-ancestry subjects was approximately 50% lower than in whites, whereas DBP measured by polyclonal DBP antibodies or proteomic methods was not lower in African-ancestry. Calculated f25OHD (using polyclonal DBP assays) correlated strongly with directly measured f25OHD (r = 0.80-0.83). Free 25OHD, measured or calculated from polyclonal DBP assays, reflected total 25OHD concentration irrespective of race and was lower in African Americans than in US whites. CONCLUSIONS: Previously reported racial differences in DBP concentration are likely from monoclonal assay bias, as there was no racial difference in DBP concentration by other methods. This confirms the poor vitamin D status of many African-Americans and the utility of total 25OHD in assessing vitamin D in the general population.
Assuntos
Proteína de Ligação a Vitamina D/sangue , Vitamina D/análogos & derivados , Adulto , Idoso , População Negra , Estudos Transversais , Humanos , Masculino , Vitamina D/sangue , População BrancaRESUMO
RATIONALE: Vitamin D deficiency, often defined by total serum 25-hydroxyvitamin D (25[OH]D) <20 ng/ml, is common in critically ill patients, with associations with increased mortality and morbidity in the intensive care unit. Correction of vitamin D deficiency in critical illness has been recommended, and ongoing clinical trials are investigating the effect of repletion on patient outcome. The biologically active amount of 25(OH)D depends on the concentration and protein isoform of vitamin D-binding protein (VDBP), which is also an acute-phase reactant affected by inflammation and injury. OBJECTIVES: We performed a secondary analysis of a cohort of critically ill children in which we reported a high rate of vitamin D deficiency, to examine how VDBP level and genotype would impact vitamin D status. METHODS: We prospectively enrolled 511 children admitted to the pediatric intensive care unit over a 12-month period. MEASUREMENTS AND MAIN RESULTS: We measured serum VDBP in 479 children. We genotyped single nucleotide polymorphisms rs7041 and rs4588 in the VDBP gene (GC) to determine haplotypes GC1F, GC1S, and GC2 in 178 subjects who consented, then calculated bioavailable 25(OH)D from serum 25(OH)D, VDBP, albumin, and GC haplotype. The median serum VDBP level was 159 µg/ml (interquartile range, 108-221), lower than has been reported in healthy children. Factors predicting lower levels in multivariate analysis included age <1 year, nonwhite race, being previously healthy, 25(OH)D <20 ng/ml and greater illness severity. In the subgroup that was genotyped, GC haplotype had the strongest association with VDBP level; carriage of one additional copy of GC1S was associated with a 37.5% higher level (95% confidence interval, 31.9-44.8; P < 0.001). Bioavailable 25(OH)D was also inversely associated with illness severity (r = -0.24, P < 0.001), and ratio to measured total 25(OH)D was variable and related to haplotype. CONCLUSIONS: Physiologic deficiency of 25(OH)D in critical illness may be more difficult to diagnose, given that lower VDBP levels increase bioavailability. Treatment studies conducted on the basis of total 25(OH)D level, without consideration of VDBP concentration and genotype, may increase the risk of falsely negative results.