• Clinical and Experimental Pediatrics
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• 제54권2호
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• pp.51-54
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• 2011

Vitamin D is present in two forms, ergocalciferol (vitamin $D_2$) produced by plants and cholecalciferol (vitamin $D_3$) produced by animal tissues or by the action of ultraviolet light on 7-dehydrocholesterol in human skin. Both forms of vitamin D are biologically inactive pro-hormones that must undergo sequential hydroxylations in the liver and the kidney before they can bind to and activate the vitamin D receptor. The hormonally active form of vitamin D, 1,25-dihydroxyvitamin D3 $[1,25(OH)_2D]$, plays an essential role in calcium and phosphate metabolism, bone growth, and cellular differentiation. Renal synthesis of $1,25(OH)_2D$ from its endogenous precursor, 25-hydroxyvitamin D (25OHD), is the rate-limiting and is catalyzed by the $1{\alpha}$-hydroxylase. Vitamin D dependent rickets type I (VDDR-I), also referred to as vitamin D $1{\alpha}$-hydroxylase deficiency or pseudovitamin D deficiency rickets, is an autosomal recessive disorder characterized clinically by hypotonia, muscle weakness, growth failure, hypocalcemic seizures in early infancy, and radiographic findings of rickets. Characteristic laboratory features are hypocalcemia, increased serum concentrations of parathyroid hormone (PTH), and low or undetectable serum concentrations of $1,25(OH)_2D$ despite normal or increased concentrations of 25OHD. Recent advances have showed in the cloning of the human $1{\alpha}$-hydroxylase and revealed mutations in its gene that cause VDDR-I. This review presents the biology of vitamin D, and $1{\alpha}$-hydroxylase mutations with clinical findings.

• 한국독성학회:학술대회논문집
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• 한국독성학회 2001년도 International Symposium on Dietary and Medicinal Antimutgens and Anticarcinogens
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• pp.52-53
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• 2001

In order for vitamin D to be active, it needs to get metabolized to 1, 25 (OH)$_2$D3. This active metabolite of vitamin D induces epithelial cell differentiation and is antiproliferative. However, at the efficacious concentration, the natural ligand for VDR is hypercalcemic and toxic to cells. Therefore, numerous analogs have been synthesized with the hope of generating a compound that retains vitamin D activity and is non-toxic.(omitted)

• 한국독성학회:학술대회논문집
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• 한국독성학회 2001년도 International Symposium on Effects of Edible Phytochemicals and Their Synthetic Derivatives on Carcinogenesis and Mutagenesis
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• pp.9-10
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• 2001

In order for vitamin D to be active, it needs to get metabolized to 1, 25 (OH)$_2$D3. This active metabolite of vitamin D induces epithelial cell differentiation and is antiproliferative. However, at the efficacious concentration, the natural ligand for VDR is hypercalcemic and toxic to cells. Therefore, numerous analogs have been synthesized with the hope of generating a compound that retains vitamin D activity and is non-toxic.(omitted)

• Tuberculosis and Respiratory Diseases
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• 제79권3호
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• pp.153-157
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• 2016

Background: Vitamin D is known to have diverse effects on various systems in the body. There is evidence to suggest that a link exists between the serum vitamin D status and tuberculosis. The present study was designed to assess the alterations in serum 25-hydroxyvitamin D levels in newly diagnosed sputum acid fast bacilli (AFB) positive pulmonary tuberculosis patients and to study the association, if any, between serum vitamin D levels and different levels of sputum smear positivity. Methods: Serum 25-hydroxyvitamin D levels were estimated in 65 sputum AFB positive pulmonary tuberculosis patients and 65 age and gender-matched healthy controls. Results: The levels of serum 25 hydroxy-vitamin D in tuberculosis patients were not statistically different from the levels of serum 25 hydroxy-vitamin D in healthy controls. However, among patients with pulmonary tuberculosis, there was a significant negative correlation between the levels of serum 25 hydroxy-vitamin D and levels of sputum positivity. Conclusion: Serum vitamin D levels negatively correlates with bacterial load in patients with active pulmonary tuberculosis.

• Journal of Animal Science and Technology
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• 제56권8호
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• pp.33.1-33.8
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• 2014

Background: Sox 9 is a major marker of chondrocyte differentiation. When chondrocytes are cultured in vitro they progressively de-differentiate and this is associated with a decline in Sox 9 expression. The active form of vitamin D, 1, 25 $(OH)_2D_3$ has been shown to be protective of cartilage in both humans and animals. In this study equine articular chondrocytes were grown in culture and the effects of 1, 25 $(OH)_2D_3$ upon Sox 9 expression examined. The expression of the transient receptor potential vanilloid (TRPV) ion channels 5 and 6 in equine chondrocytes in vitro, we have previously shown, is inversely correlated with de-differentiation. The expression of these channels in response to 1, 25 $(OH)_2D_3$ administration was therefore also examined. Results: The active form of vitamin D (1, 25 $(OH)_2D_3$ when administered to cultured equine chondrocytes at two different concentrations significantly increased the expression of Sox 9 at both. In contrast 1, 25 $(OH)_2D_3$ had no significant effect upon the expression of either TRPV 5 or 6 at either the protein or the mRNA level. Conclusions: The increased expression of Sox 9, in equine articular chondrocytes in vitro, in response to the active form of vitamin D suggests that this compound could be utilized to inhibit the progressive de-differentiation that is normally observed in these cells. It is also supportive of previous studies indicating that $1{\alpha}$, 25-dihydroxyvitamin $D_3$ can have a protective effect upon cartilage in animals in vivo. The previously observed correlation between the degree of differentiation and the expression levels of TRPV 5/6 had suggested that these ion channels may have a direct involvement in, or be modulated by, the differentiation process in vitro. The data in the present study do not support this.

• Nutritional Sciences
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• 제9권1호
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• pp.42-47
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• 2006

It has been reported that taking a proper amount of calcium and vitamin D helps to increase bone mineral density (BMD) and is effective in decreasing the risk of osteoporosis. This study investigated the supplementary effects of calcium and vitamin D on postmenopausal women who had osteoporosis and used calcium and vitamin D supplements. The study subjects consisted of osteoporotic postmenopausal women who were recruited from the Department of Orthopedics in a university-affiliated hospital. Sixty-seven study subjects were orally administrated 1,000 mg of calcium (calcium carbonate) and 2.5 mg of active vitamin D (1-$\alpha$ hydroxyvitamin D) (cholecalciferol 250 IU) twice a day for a year and a half. BMD and biochemical markers were evaluated and repeated every six months. One year after the intervention test, the bone mineral density of the lumbar spine was significantly increased as compared to the baseline. Six months after supplement administration, the level of serum alkaline phosphatase began to decrease, and afterwards a significant difference was maintained Concentration of 1, 25-dihydroxy-vitamin D at 1.5 years was higher than that of the baseline. In comparison with that of the baseline, the level of urinary hydroxyproline in the study subjects over six months was significantly decreased This study continued that effects such as BMD improvement and changes in biochemical markers appeared at least one year after administration of supplements.

• Asian Pacific Journal of Cancer Prevention
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• 제15권17호
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• pp.7337-7341
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• 2014

Background: The physiological role of vitamin D extends beyond bone health and calcium-phosphate homeostasis to effects on cancer risk, mainly for colorectal cancer. Vitamin D may have an anticancer effect in colorectal cancer mediated by binding of the active form $1,25(OH)_2D$ to the vitamin D receptor (VDR). The Taq1 VDR gene polymorphism, a C-to-T base substitution (rs731236) in exon 9 may influence its expression and function. The aim of this study wass to determine the 25(OH)D vitamin D level and to investigate the association between circulating vitamin D level and Taq1VDR gene polymorphism among Jordanian colorectal cancer patients. Materials and Methods: This case control study enrolled ninety-three patients and one hundred and two healthy Jordanian volunteers from AL-Basheer Hospital/Amman (2012-2013). Ethical approval and signed consent forms were obtained from all participants before sample collection. 25(OH)D levels were determined by competitive immunoassay Elecsys (Roche Diagnostic, France). DNA was extracted (Promega, USA) and amplified by PCR followed by VDR Taq1 restriction enzyme digestion. The genotype distribution was evaluated by paired t-test and chi-square. Comparison between vitamin D levels among CRC and control were assessed by odds ratio with 95% confidence interval. Results: The vitamin D serum level was significantly lower among colorectal cancer patients (8.34 ng/ml) compared to the healthy control group (21.02ng/ml). Patients deficient in vitamin D (less than 10.0 ng/ml) had increased colorectal cancer risk 19.2 fold compared to control. Only 2.2% of CRC patients had optimal vitamin D compared to 23.5% among healthy control. TT, Tt and tt Taq1 genotype frequencies among CRC cases was 35.5%, 50.5% and 14% compared to 43.1%, 41.2% and 15.7% among healthy control; respectively. CRC patients had lower mean vitamin D level among TT ($8.91{\pm}4.31$) and Tt ($9.15{\pm}5.25$) genotypes compared to control ($21.3{\pm}8.31$) and ($19.3{\pm}7.68$); respectively. Conclusions: There is significant association between low 25(OH)D serum level and colorectal cancer risk. The VDRTaq1 polymorphism was associated with increased colorectal cancer risk among patient with VDRTaq1 TT and Tt genotypes. Understanding the functional mechanism of VDRTaq1 TT and Tt may provide a strategy for colorectal cancer prevention and treatment.

• Childhood Kidney Diseases
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• 제26권1호
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• pp.63-67
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• 2022

Nephrocalcinosis often occurs in infants and is caused by excessive calcium or vitamin D supplementation, neonatal primary hyperparathyroidism, and genetic disorders. Idiopathic infantile hypercalcemia (IIH), a rare cause of nephrocalcinosis, results from genetic defects in CYP24A1 or SLC34A1. Mutations in CYP24A1, which encodes 25-hydroxyvitamin D 24-hydroxylase, disrupt active vitamin D degradation. IIH clinically manifests as failure to thrive and hypercalcemia within the first year of life and usually remits spontaneously. Herein, we present a case of IIH wih CYP24A1 mutations. An 11-month-old girl visited our hospital with incidental hypercalcemia. She showed failure to thrive, and her oral intake had decreased over time since the age of 6 months. Her initial serum parathyroid hormone level was low, 25-OH vitamin D and 1,25(OH)₂ vitamin D levels were normal, and renal ultrasonography showed bilateral nephrocalcinosis. Whole-exome sequencing revealed compound heterozygous variants in CYP24A1 (NM_000782.4:c.376C>T [p.Pro126Ser] and c.1310C>A [p.Pro437His]). Although her hypercalcemia and poor oral intake spontaneously resolved in approximately 8 months, we suggested that her nephrocalcinosis and renal function be regularly checked in consideration of potential asymptomatic renal damage. Hypercalcemia caused by IIH should be suspected in infants with severe nephrocalcinosis, especially when presenting with failure to thrive.

• Nutrition Research and Practice
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• 제9권2호
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• pp.158-164
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• 2015

BACKGROUND/OBJECTIVES: Vitamin D deficiency is common in hemodialysis patients. The aim of this study was to identify whether or not sun exposure and dietary vitamin D intake have effects on serum 25-hydroxyvitamin D (25(OH)D) status in hemodialysis (HD) patients. The objective was to identify the main determinants of serum vitamin D status in the study subjects. SUBJECTS/METHODS: A cross-sectional study of 47 HD patients (19 males and 28 females) was performed. We assessed serum 25(OH)D and $1,25(OH)_2D$ levels between August and September 2012 and analyzed the prevalence of vitamin D deficiency in HD patients. To evaluate the determinants of serum 25(OH)D levels, we surveyed dietary vitamin D intake, degree of sun exposure, and outdoor activities. To compare biological variables, serum 25(OH)D was stratified as below 15 ng/ml or above 15 ng/ml. RESULTS: Mean 25(OH)D and $1,25(OH)_2D$ levels were $13.5{\pm}5.8ng/ml$ and $20.6{\pm}11.8pg/ml$, respectively. The proportions of serum 25(OH)D deficiency (< 15 ng/ml), insufficiency (15-< 30 ng/ml), and sufficiency (${\geq}30ng/ml$) in subjects were 72.4%, 23.4%, and 4.3%, respectively. Prevalence of vitamin D deficiency in female patients was 78.6%, whereas that in males was 63.2% (P = 0.046). Vitamin D intake and sun exposure time were not significantly different between the two stratified serum 25(OH)D levels. Dietary intake of vitamin D did not contribute to increased serum 25(OH)D levels in HD patients. The main effective factors affecting serum 25(OH)D status were found to be the sun exposure and active outdoor exercise. CONCLUSIONS: Hypovitaminosis D is common in HD patients and is higher in females than in males. Sun exposure is the most important determinant of serum 25(OH)D status in HD patients.

• 대한치과교정학회지
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• 제28권4호
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• pp.627-640
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• 1998

골 성장 및 개조에 관여하는 전신적 조절인자인 $1,25-(OH)_2D_3$와 국소적 조절인자인 $TGF-{\beta}$가 사람의 치주인대세포 기능에 미치는 영향을 관찰하고자 그 인자들을 단독 혹은 복합적으로 치주인대세포에 가하여 그 활성 변화를 측정하여 다음과 같은 결과를 얻었다. 1. 10ng/m1 농도의 vitamin $D_3$를 치주인대세포에 가한 후 배양 1, 2, 3일째의 활성은 대조군과 차이가 없었으나, 50ng/ml 농도로 가한 후 배양 3째일에는 대조군에 비해 유의하게 증가하였으며, 100ng/m1 농도에서는 배양 1, 2, 3일째에 유의하게 증가하였다. 2. 0.1ng/ml 농도의 $TGF-{\beta}$를 치주인대세포에 가한 후 배양 1, 2, 3일째의 활성은 대조군과 유의한 차이가 없었으나, 1ng/ml나 5ng/ml농도의 $TGF-{\beta}$를 가한 경우 배양 3일째에 유의하게 증가되었으며 10ng/ml농도의 경우에는 배양 2, 3일째에 유의하게 증가하였다. 3. 1ng/ml 농도의 $TGF-{\beta}$와 다양한 농도의 vitamin $D_3$를 혼합투여한 경우, 100ng/m1 농도의 vitamin $D_3$로 배양 3일째에 유의한 활성 증가를 볼 수 있었다. 4. 5ng/ml 농도의 $TGF-{\beta}$와 다양한 농도의 vitamin $D_3$를 혼합투여한 경우, 10, 50, 100ng/m1의 vitamin $D_3$에서 공히 배양 2일째부터 유의한 활성 증가를 보였으나 10ng/ml에서는 배양 3일째에 그 활성이 유지되지 못하였다. 5. 10ng/ml농도의 $TGF-{\beta}$와 다양한 농도의 vitamin $D_3$를 혼합투여한 경우, 50ng/ml의 vitamin $D_3$에서는 배양 2일째부터 100ng/m1의 vitamin $D_3$에서는 1일째부터 유의한 활성 증가를 보였다.