vitamin d metabolism
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2022 ◽  
Vol 23 (2) ◽  
pp. 841
Author(s):  
Shelley Griess-Fishheimer ◽  
Janna Zaretsky ◽  
Tamara Travinsky-Shmul ◽  
Irina Zaretsky ◽  
Svetlana Penn ◽  
...  

The severe impairment of bone development and quality was recently described as a new target for unbalanced ultra-processed food (UPF). Here, we describe nutritional approaches to repair this skeletal impairment in rats: supplementation with micro-nutrients and a rescue approach and switching the UPF to balanced nutrition during the growth period. The positive effect of supplementation with multi-vitamins and minerals on bone growth and quality was followed by the formation of mineral deposits on the rats’ kidneys and modifications in the expression of genes involved in inflammation and vitamin-D metabolism, demonstrating the cost of supplementation. Short and prolonged rescue improved trabecular parameters but incompletely improved the cortical parameters and the mechanical performance of the femur. Cortical porosity and cartilaginous lesions in the growth-plate were still detected one week after rescue and were reduced to normal levels 3 weeks after rescue. These findings highlight bone as a target for the effect of UPF and emphasize the importance of a balanced diet, especially during growth.


Author(s):  
John P. Bilezikian ◽  
Anna Maria Formenti ◽  
Robert A. Adler ◽  
Neil Binkley ◽  
Roger Bouillon ◽  
...  

AbstractThe 4th International Conference on Controversies in Vitamin D was held as a virtual meeting in September, 2020, gathering together leading international scientific and medical experts in vitamin D. Since vitamin D has a crucial role in skeletal and extra-skeletal systems, the aim of the Conference was to discuss improved management of vitamin D dosing, therapeutic levels and form or route of administration in the general population and in different clinical conditions. A tailored approach, based on the specific mechanisms underlying vitamin D deficiency in different diseases that were discussed, was recommended. Specifically, in comparison to healthy populations, higher levels of vitamin D and greater amounts of vitamin D were deemed necessary in osteoporosis, diabetes mellitus, obesity (particularly after bariatric surgery), and in those treated with glucocorticoids. Emerging and still open issues were related to target vitamin D levels and the role of vitamin D supplementation in COVID-19 since low vitamin D may predispose to SARS-CoV-2 infection and to worse COVID-19 outcomes. Finally, whereas oral daily cholecalciferol appears to be the preferred choice for vitamin D supplementation in the general population, and in most clinical conditions, active vitamin D analogs may be indicated in patients with hypoparathyroidism and severe kidney and liver insufficiency. Parenteral vitamin D administration could be helpful in malabsorption syndromes or in states of vitamin D resistance.Specific guidelines for desired levels of vitamin D should be tailored to the different conditions affecting vitamin D metabolism with the goal to define disease-specific normative values.


Author(s):  
Dieter Haffner ◽  
Maren Leifheit-Nestler ◽  
Andrea Grund ◽  
Dirk Schnabel

AbstractRickets is a disease of the growing child arising from alterations in calcium and phosphate homeostasis resulting in impaired apoptosis of hypertrophic chondrocytes in the growth plate. Its symptoms depend on the patients’ age, duration of disease, and underlying disorder. Common features include thickened wrists and ankles due to widened metaphyses, growth failure, bone pain, muscle weakness, waddling gait, and leg bowing. Affected infants often show delayed closure of the fontanelles, frontal bossing, and craniotabes. The diagnosis of rickets is based on the presence of these typical clinical symptoms and radiological findings on X-rays of the wrist or knee, showing metaphyseal fraying and widening of growth plates, in conjunction with elevated serum levels of alkaline phosphatase. Nutritional rickets due to vitamin D deficiency and/or dietary calcium deficiency is the most common cause of rickets. Currently, more than 20 acquired or hereditary causes of rickets are known. The latter are due to mutations in genes involved in vitamin D metabolism or action, renal phosphate reabsorption, or synthesis, or degradation of the phosphaturic hormone fibroblast growth factor 23 (FGF23). There is a substantial overlap in the clinical features between the various entities, requiring a thorough workup using biochemical analyses and, if necessary, genetic tests. Part I of this review focuses on the etiology, pathophysiology and clinical findings of rickets followed by the presentation of a diagnostic approach for correct diagnosis. Part II focuses on the management of rickets, including new therapeutic approaches based on recent clinical practice guidelines.


2021 ◽  
Vol 67 (6) ◽  
pp. 68-79
Author(s):  
I. S. Maganeva ◽  
E. A. Pigarova ◽  
N. V. Shulpekova ◽  
L. K. Dzeranova ◽  
A. K. Eremkina ◽  
...  

BACKGROUND: Vitamin D (25-hydroxyvitamin D [25(ОН)D]) deficiency (<20 ng/mL) and insufficiency (20–29 ng/mL) are common in primary hyperparathyroidism (PHPT), but data regarding the vitamin D metabolism in this population is limited.AIM: The aim of this study is to estimate the vitamin D metabolites and their relationship with the main parameters of phosphorus-calcium metabolism in patients with PHPT at baseline and on the background of a single dose of cholecalciferol 150,000 IU.MATERIALS AND METHODS: A single-center interventional, dynamic, prospective, comparative study has been carried out. The study included 54 participants, divided into two groups: the 1st group included 27 patients with confirmed PHPT, the 2nd control group (n = 27), matched on gender (p = 0.062). The study included 4 visits; the baseline laboratory examination and a bolus dose of cholecalciferol were performed at the visit 1, the subsequent visits included a dynamic laboratory examination.RESULTS: Vitamin D deficiency (<20 ng/ml) was detected in 69% of patients with PHPT. In the PHPT group (before cholecalciferol therapy), there was a direct association of 1.25(OH)2 D3 with albumin-corrected and ionized calcium, as well as between the 25(OH)D3 /24.25(OH)2 D3 ratio with PTH and magnesium. After taking of cholecalciferol, the levels of 1.25(OH)2 D3 and 25(OH)D3 /24.25(OH)2 D3 were significantly increased, and the levels of 25(OH)D3 /1.25(OH)2 D3 were significantly declined at all visits among patients with PHPT. The common 25(OH)D level was comparable to the control group, however the levels of 1,25(OH)2 D3 in patients with PHPT were 55% higher at baseline, and after taking of cholecalciferol 150,000 IU. They remained increased by 3–7 days by an additional 23–36%, significantly higher than those in the control group: 44%, 74% and 65%, at visits 2, 3 and 4, respectively (p<0.05). The taking of 150,000 IU cholecalciferol in the PHPT group did not lead to a significant increase in hypercalcemia and hypercalciuria, which indicates the safety of this dose in patients with mild hypercalcemia (albumin corrected calcium <3 mmol/l). None of the study participants experienced any side effects.CONCLUSION: The completely comprehensive assessment of vitamin D metabolites was carried out for the first time in patients with PHPT before and after using a bolus dose of cholecalciferol. The results confirmed the differences of vitamin D metabolism in chronic excessive secretion of PTH compared to control group, which is new data in the pathogenesis of the disease, and can be used to develop optimal regimens for cholecalciferol taking in this population. 


PLoS ONE ◽  
2021 ◽  
Vol 16 (12) ◽  
pp. e0261097
Author(s):  
Max Mimpen ◽  
Linda Rolf ◽  
Geert Poelmans ◽  
Jody van den Ouweland ◽  
Raymond Hupperts ◽  
...  

Introduction A poor 25-hydroxyvitamin D (25(OH)D) status is a much replicated risk factor for developing multiple sclerosis (MS), and several vitamin D-associated single nucleotide polymorphisms (SNPs) have been associated with a higher risk of MS. However, studies on the benefit of vitamin D supplementation in MS show inconclusive results. Here, we explore whether vitamin D-associated SNPs and MS risk alleles confound serological response to vitamin D supplementation. Methods 34 participants from the SOLARIUM study consented to genotyping, of which 26 had vitamin D data available. The SOLARIUM study randomised relapsing-remitting MS patients to placebo or 14,000 IU vitamin D3 for 48 weeks. Participants were categorised as either ‘carriers’ or ‘non-carriers’ of the risk allele for 4 SNPs: two related to D binding protein (DBP) and associated with lower 25(OH)D levels (rs4588 and rs7041), and two related to vitamin D metabolism enzymes CYP27B1 and CYP24A1 and associated with a higher risk of MS (rs12368653; rs2248359, respectively). 25(OH)D levels were determined at baseline and after 48 weeks. Results The DBP-related SNPs showed no difference in 25(OH)D status at baseline, but carriers of the rs7041 risk allele showed lower 25(OH)D-levels compared to non-carriers after 48 weeks of supplementation (median 224.2 vs. 332.0 nmol/L, p = 0.013). For CYP related SNPs, neither showed a difference at baseline, but carriers of the rs12368653 risk allele showed higher 25(OH)D-levels compared to non-carriers after 48 weeks of supplementation (median 304.1 vs. 152.0 nmol/L, p = 0.014). Discussion Vitamin D-related SNPs affect the serological response to high-dose vitamin D supplementation. The effects on more common doses of vitamin D, as well as the clinical consequence of this altered response, need to be investigated further.


2021 ◽  
Vol 12 ◽  
Author(s):  
Tian-Ping Zhang ◽  
Hong-Miao Li ◽  
Qian Huang ◽  
Li Wang ◽  
Xiao-Mei Li

Abnormal vitamin D metabolism is involved in the pathogenesis of rheumatoid arthritis (RA). In this study, we evaluated the association of single nucleotide polymorphisms (SNPs) and methylation levels in vitamin D metabolic pathway genes with RA susceptibility. Ten SNPs in vitamin D metabolic pathway genes (CYP2R1, CYP24A1, VDR, CYP27B1) were genotyped in 477 RA patients and 496 controls by improved multiple ligase detection reaction (iMLDR). The methylation levels of the promoter regions of these genes were detected in 122 RA patients and 123 controls using Illumina Hiseq platform. We found that the CYP2R1 rs1993116 GA genotype, CYP27B1 rs4646536 GA genotype, rs4646536 A allele frequencies were significantly increased in RA patients when compared to controls. The decreased risk of rs1993116, rs4646536 was found under the dominant mode in RA patients. However, no significant association was found between CYP2R1 rs7936142, rs12794714, CYP24A1 rs2762934, rs6068816, rs2296239, rs2296241, VDR rs11574129, rs3847987 polymorphism, and RA susceptibility. The VDR, CYP27B1 methylation levels in RA patients were significantly lower than those in controls, while CYP2R1, CYP24A1 methylation levels were not associated with RA. There were no statistical associations between CYP2R1, CYP24A1, VDR, CYP27B1 methylation levels and their respective genotype in RA patients. In addition, plasma 25OHD level in RA patients was significantly lower than that in healthy controls. In summary, our results showed that CYP2R1, CYP27B1 genetic variations were associated with the genetic background of RA, while altered VDR, CYP27B1 methylation levels were related to the risk of RA.


Author(s):  
Наталия Александровна Полушкина ◽  
Наталия Владимировна Чиркова ◽  
Жанна Владимировна Вечеркина ◽  
Кристина Павловна Кубышкина ◽  
Марина Николаевна Бобешко

Витамин Д является жирорастворимым витамином, который в организме человека вырабатывается только при определённых условиях, когда ультрафиолетовые лучи солнечного света попадают на кожу человека. В организм человека витамин Д поступает в ограниченном количестве 20- 30% от потребности , в таких продуктах питания как: лосось(200-800 МЕ на 100 г), сметана-50 МЕ, печень говяжья-45МЕ, масло сливочное-10-150 МЕ, молоко, обогащённое витамином Д, желтки яиц-45 МЕ. Витамину Д для активации в организме необходимо пройти два процесса гидроксилирования. Первый из них происходит в печени (до 90%) и превращает витамин Д в 25-гидроксивитамин Д-25(ОН)Д или кальцидиол. Второй этап происходит в почках (10%), в результате чего синтезируется активный 1,25 -дигидроксивитамин Д или кальцитриол. Уровень образования Д-гормона в организме взрослого человека составляет около 0,3-1,0 мкг/сут. Важнейшая реакция, в которой участвует витамин Д - абсорбция кальция в кишечнике и его реабсорбция в почках, поддержание необходимого уровня кальция и фосфатов в крови, он необходим для роста костей и процессов костного ремоделирования. Чтобы сохранить нормальный гомеостаз кальция и костного ремоделирования, организму необходимо получать витамин D3. В условиях физиологии его потребность варьирует в сутки от двухсот-четырёхсот МЕ (у взрослых людей), до шестисот-восьмисот МЕ (у людей пожилого возраста) и до одной тысячи МЕ у лиц, живущих в районах Крайнего Севера. Концентрация промежуточного метаболита [25-(OH)D3] в сыворотке крови считается самым надёжным показателем общего обмена витамина D, поэтому этот показатель может быть использован для определения обеспеченности организма витамином D. Также он необходим для выяснения причин патологических концентраций кальция в сыворотке крови пациентов. Адекватное содержание [25-(OH)D3] поддерживает абсорбцию кальция и костный метаболизм. Содержание же [25-(OH)D3] ниже целевого значения 30 нг/мл вызывает снижение кальция в плазме крови и повышение секреции ПТГ, и как следствие, остеокластическую резорбцию кости, нарушение процессов ремоделирования и минерализации костной ткани, снижение её плотности и изменение костной архитектуры Vitamin D is a fat-soluble vitamin that is produced in the human body only under certain conditions, when ultraviolet rays of sunlight fall on the human skin. The human body receives vitamin D in a limited amount of 20-30% of the need, in such food products as: salmon (200-800 IU per 100 g), sour cream-50 IU, beef liver-45 IU, butter-10-150 IU, milk enriched with vitamin D, egg yolks-45 IU. Vitamin D needs to undergo two hydroxylation processes to be activated in the body. The first of these occurs in the liver (up to 90%) and converts vitamin D to 25-hydroxyvitamin D-25(OH)D or calcidiol. The second stage occurs in the kidneys (10%), resulting in the synthesis of active 1,25 -dihydroxyvitamin D or calcitriol. The level of D-hormone formation in the adult body is about 0.3-1.0 mcg/day. The most important reaction in which vitamin D is involved is the absorption of calcium in the intestine and its reabsorption in the kidneys, maintaining the necessary level of calcium and phosphates in the blood, it is necessary for bone growth and bone remodeling processes. To maintain normal calcium homeostasis and bone remodeling, the body needs to receive vitamin D3. In the conditions of physiology, its need varies per day from two hundred to four hundred IU (in adults), to six hundred to eight hundred IU (in the elderly) and up to one thousand IU in people living in the Far North. The concentration of the intermediate metabolite [25-(OH)D3] in the blood serum is considered the most reliable indicator of the total vitamin D metabolism, so this indicator can be used to determine the body's vitamin D supply. It is also necessary to find out the causes of abnormal concentrations of calcium in the blood serum of patients. Adequate [25-(OH)D3] content supports calcium absorption and bone metabolism. The content of [25-(OH)D3] below the target value of 30 ng / ml causes a decrease in calcium in the blood plasma and an increase in PTH secretion, and as a result, osteoclastic bone resorption, a violation of the processes of bone remodeling and mineralization, a decrease in its density and a change in bone architecture


Nutrients ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 4329
Author(s):  
Alexandra Povaliaeva ◽  
Viktor Bogdanov ◽  
Ekaterina Pigarova ◽  
Artem Zhukov ◽  
Larisa Dzeranova ◽  
...  

In this study we aimed to assess vitamin D metabolism in patients with Cushing’s disease (CD) compared to healthy individuals in the setting of bolus cholecalciferol treatment. The study group included 30 adults with active CD and the control group included 30 apparently healthy adults with similar age, sex and BMI. All participants received a single dose (150,000 IU) of cholecalciferol aqueous solution orally. Laboratory assessments including serum vitamin D metabolites (25(OH)D3, 25(OH)D2, 1,25(OH)2D3, 3-epi-25(OH)D3 and 24,25(OH)2D3), free 25(OH)D, vitamin D-binding protein (DBP) and parathyroid hormone (PTH) as well as serum and urine biochemical parameters were performed before the intake and on Days 1, 3 and 7 after the administration. All data were analyzed with non-parametric statistics. Patients with CD had similar to healthy controls 25(OH)D3 levels (p > 0.05) and higher 25(OH)D3/24,25(OH)2D3 ratios (p < 0.05) throughout the study. They also had lower baseline free 25(OH)D levels (p < 0.05) despite similar DBP levels (p > 0.05) and lower albumin levels (p < 0.05); 24-h urinary free cortisol showed significant correlation with baseline 25(OH)D3/24,25(OH)2D3 ratio (r = 0.36, p < 0.05). The increase in 25(OH)D3 after cholecalciferol intake was similar in obese and non-obese states and lacked correlation with BMI (p > 0.05) among patients with CD, as opposed to the control group. Overall, patients with CD have a consistently lower 25(OH)D3/24,25(OH)2D3 ratio, which is indicative of a decrease in 24-hydroxylase activity. This altered activity of the principal vitamin D catabolism might influence the effectiveness of cholecalciferol treatment. The observed difference in baseline free 25(OH)D levels is not entirely clear and requires further study.


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