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1.
Anticancer Res ; 40(2): 719-722, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-32014913

RESUMO

AIM: A commercially available light emitting diode (LED) that transmitted narrow band ultraviolet B (UVB) radiation was evaluated for its efficacy and efficiency to produce vitamin D3 in human skin. MATERIALS AND METHODS: Human skin samples were obtained from surgical procedures. The LED had peak emission wavelength of 295 nm. Skin samples were exposed to the UVB-LED for varying times and then were analyzed by high-pressure liquid chromatography (HPLC) to determine the vitamin D3 content. RESULTS: There was a statistically significant time- and dose-dependent increase in the percent of 7-dehydrocholesterol that was converted to vitamin D3 in the skin type II samples; 1.3%±0.5, 2.3%±0.6 and 4.5%±1.67 after exposure to 0.75 (11.7 mJ/cm2), 1.5 (23.4 mJ/cm2) and 3 (46.8 mJ/cm2) minimal erythemal doses (MEDs), respectively. CONCLUSION: The UVB-LED was effective and efficient in generating vitamin D3 in human skin, in vitro. The amount of vitamin D3 production increased in a dose-dependent fashion with increased UVB energy. UVB-LEDs can be developed for devices that can efficiently produce vitamin D3 in human skin.


Assuntos
Colecalciferol/biossíntese , Pele/metabolismo , Pele/efeitos da radiação , Raios Ultravioleta , Colecalciferol/metabolismo , Cromatografia Líquida de Alta Pressão , Desidrocolesteróis/metabolismo , Relação Dose-Resposta à Radiação , Humanos
2.
Anticancer Res ; 40(1): 565-572, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31892613

RESUMO

BACKGROUND/AIM: To assess the effectiveness of three UV emitting lamps on the cutaneous production of vitamin D3, a marker of DNA damage and nitric oxide production in human skin. MATERIALS AND METHODS: Human skin samples (skin types II, III and IV) obtained from surgery were exposed to three different UV emitting lamps for varying times and then extracted and chromatographed to determine the vitamin D3 content. The skin samples exposed to the 3 UV emitting lamps were also evaluated for 8-hydroxy-2'-deoxyguanosine (a marker of DNA damage) and nitric oxide production. RESULTS: It was observed that the spectral output of the 3 lamps had different effects on the cutaneous production of vitamin D3, 8-hydroxy-2'-deoxyguanosine and nitric oxide production. One lamp demonstrated optimal production of vitamin D3 with the least amount of DNA damage and intermediate production of nitric oxide suggesting that it could be developed into a device for treating vitamin D deficiency. CONCLUSION: The spectral output of the experimental UVB emitting lamps significantly influenced the cutaneous production of vitamin D3 8-hydroxy-2'-deoxyguanosine and nitric oxide.


Assuntos
/biossíntese , Colecalciferol/biossíntese , Óxido Nítrico/biossíntese , Pele/metabolismo , Pele/efeitos da radiação , Raios Ultravioleta , Relação Dose-Resposta à Radiação , Eritema/etiologia , Humanos
3.
Nutr Hosp ; 36(Spec No3): 3-7, 2019 Aug 27.
Artigo em Espanhol | MEDLINE | ID: mdl-31368328

RESUMO

Introduction: Vitamin D is an essential nutrient whose deficiency has been associated with the risk of various chronic diseases such as osteoporosis, hypertension, cardiovascular disease, diabetes, some types of cancer and even overweight and obesity. Although vitamin D can be synthesized at the skin from exposure to sunlight, this source is not always sufficient to meet the needs. For example, the use of sunscreen or the low exposition to the sunlight limits the syntheses. In fact, studies have found that at least half of the Spanish population has vitamin D deficits. Therefore, the dietary contribution is fundamental. Although there are different foods fortified in this vitamin, few products are natural source of it, as fatty fish and eggs. However, according to different studies carried out in the Spanish population, there is a low consumption of this food group. In this way, it would be advisable to promote egg consumption among the population, since this food, in addition to having many nutrients, contains a high amount of vitamin D, which contributes to avoid the appearance of deficiencies and the consequences health consequences that this implies.


Assuntos
Colecalciferol/administração & dosagem , Ovos , Ergocalciferóis/administração & dosagem , Deficiência de Vitamina D/dietoterapia , Vitaminas/administração & dosagem , Colecalciferol/biossíntese , Colecalciferol/sangue , Ergocalciferóis/sangue , Ergocalciferóis/metabolismo , Humanos , Política Nutricional , Espanha/epidemiologia , Luz Solar , Vitamina D/biossíntese , Vitamina D/sangue , Deficiência de Vitamina D/complicações , Deficiência de Vitamina D/epidemiologia
4.
Circ Res ; 122(11): 1576-1585, 2018 05 25.
Artigo em Inglês | MEDLINE | ID: mdl-29798901

RESUMO

Understanding of vitamin D physiology is important because about half of the population is being diagnosed with deficiency and treated with supplements. Clinical guidelines were developed based on observational studies showing an association between low serum levels and increased cardiovascular risk. However, new randomized controlled trials have failed to confirm any cardiovascular benefit from supplementation in the general population. A major concern is that excess vitamin D is known to cause calcific vasculopathy and valvulopathy in animal models. For decades, administration of vitamin D has been used in rodents as a reliable experimental model of vascular calcification. Technically, vitamin D is a misnomer. It is not a true vitamin because it can be synthesized endogenously through ultraviolet exposure of the skin. It is a steroid hormone that comes in 3 forms that are sequential metabolites produced by hydroxylases. As a fat-soluble hormone, the vitamin D-hormone metabolites must have special mechanisms for delivery in the aqueous bloodstream. Importantly, endogenously synthesized forms are carried by a binding protein, whereas dietary forms are carried within lipoprotein particles. This may result in distinct biodistributions for sunlight-derived versus supplement-derived vitamin D hormones. Because the cardiovascular effects of vitamin D hormones are not straightforward, both toxic and beneficial effects may result from current recommendations.


Assuntos
Doenças Cardiovasculares/etiologia , Vitamina D/administração & dosagem , Vitamina D/metabolismo , Vitaminas/administração & dosagem , Vitaminas/metabolismo , Fatores Etários , Aterosclerose/etiologia , Cálcio na Dieta/administração & dosagem , Cálcio na Dieta/metabolismo , Doenças Cardiovasculares/sangue , Doenças Cardiovasculares/diagnóstico , Colecalciferol/biossíntese , Colecalciferol/metabolismo , Suplementos Nutricionais/efeitos adversos , Esquema de Medicação , Alimentos , Guias como Assunto , Humanos , Hidroxilação , Estudos Observacionais como Assunto , Medicina de Precisão , Receptores de LDL/metabolismo , Luz Solar , Calcificação Vascular/etiologia , Vitamina D/efeitos adversos , Vitamina D/biossíntese , Deficiência de Vitamina D/sangue , Deficiência de Vitamina D/diagnóstico , Vitaminas/efeitos adversos
5.
J Photochem Photobiol B ; 179: 54-65, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-29334624

RESUMO

Health-optimum-exposure index (HOEI) is proposed to assess if the prescribed amount of vitamin D3 (target value) could be synthesized in the human skin without erythema appearance. It is defined as the ratio between the vitamin D3 quantity received during the maximum allowed outdoor exposure without erythema risk and the target value. Sunbathing is safe for HOEI>1 and 1/HOEI represents a part of minimal erythema dose (MED) necessary to obtain the target value. We examine the following targets: a vitamin D3 quantity equivalent to 1000 IU vitamin D3 taken orally, and an optimal vitamin D3 quantity defined by Krzyscin et al. (2016). The biologically weighted (previtamin D3 and erythemal) doses from the Northern Hemisphere midlatitudinal stations are analyzed to find HOEI dependence on personal and meteorological factors. HOEI depends mostly on the exposed skin area, person's age, and sun elevation at noon but not on the Fitzpatrick skin phototype. We found that only young adults (<21 yr) could safely obtain vitamin D3 quantity, which is equivalent to 1000 IU taken orally, almost throughout the whole year. Duration of such exposures appears <1 h only in the warm subperiods of the year (April-September) for a person with minimal erythema dose of 330 J m-2. Exposing larger part of the body (~30%) enables the oldest persons (>59 yr) to reach 1000 IU target during warm days in spring and summer. The optimal daily vitamin D3 quantity could only be synthesized only by young adults for about 40-60% of days in the May-August period if they expose at least 1/3 part of their body surface area. Vitamin D3 supplementation seems to be necessary over the whole year for the oldest persons with daily dosage of ~2000 IU but reduced to ~1000 IU in summer for sunseekers exposing significant part of the body.


Assuntos
Colecalciferol/biossíntese , Eritema/etiologia , Pele/efeitos da radiação , Luz Solar , Colecalciferol/análise , Humanos , Pessoa de Meia-Idade , Fenótipo , Estações do Ano , Pele/metabolismo , Temperatura Ambiente , Adulto Jovem
6.
Sci Rep ; 7(1): 11489, 2017 09 13.
Artigo em Inglês | MEDLINE | ID: mdl-28904394

RESUMO

Vitamin D, the sunshine vitamin is important for health. Those with fat malabsorption disorders malabsorb vitamin D and thus must rely on cutaneous production of vitamin D3. Vitamin D3 is generated secondary to exposure to ultraviolet B (UVB) radiation (whether from the sun or from an artificial source). Light emitting diodes (LEDs) have been developed to emit ultraviolet radiation. Little is known about the efficiency of UVB emitting LEDs tuned to different wavelengths for producing vitamin D3 in human skin. Ampoules containing 7-dehydrocholesterol were exposed to a LED that emitted a peak wavelength at 293, 295, 298 or 305 nm to determine their efficiency to produce previtamin D3. The 293 nm LED was best suited for evaluating its effectiveness for producing vitamin D in human skin due to the shorter exposure time. This LED was found to be 2.4 times more efficient in producing vitamin D3 in human skin than the sun in less than 1/60th the time. This has significant health implications for medical device development in the future that can be used for providing vitamin D supplementation to patients with fat malabsorption syndromes as well as patients with other metabolic abnormalities including patients with chronic kidney disease.


Assuntos
Colecalciferol/biossíntese , Pele/metabolismo , Pele/efeitos da radiação , Luz Solar , Raios Ultravioleta , Desidrocolesteróis/metabolismo , Humanos , Fatores de Tempo
7.
J Steroid Biochem Mol Biol ; 171: 187-194, 2017 07.
Artigo em Inglês | MEDLINE | ID: mdl-28330720

RESUMO

The lower risk of some internal cancers at lower latitudes has been linked to greater sun exposure and consequent higher levels of ultraviolet radiation (UVR)-produced vitamin D3 (D3). To separate the experimental effects of sunlight and of all forms of D3, a mouse in which UVR does not produce D3 would be useful. To this end we have generated mice carrying a modified allele of sterol C5-desaturase (Sc5d), the gene encoding the enzyme that converts lathosterol to 7-dehydrocholesterol (7-DHC), such that Sc5d expression can be inactivated using the Cre/lox site-specific recombination system. By crossing to mice with tissue-specific expression of Cre or CreER2 (Cre/estrogen receptor), we generated two lines of transgenic mice. One line has constitutive keratinocyte-specific inactivation of Sc5d (Sc5dk14KO). The other line (Sc5dk14KOi) has tamoxifen-inducible keratinocyte-specific inactivation of Sc5d. Mice deleted for keratinocyte Sc5d lose the ability to increase circulating D3 following UVR exposure of the skin. Thus, unlike in control mice, acute UVR exposure did not affect circulating D3 level in inducible Sc5dk14KOi mice. Keratinocyte-specific inactivation of Sc5d was proven by sterol measurement in hair - in control animals lathosterol and cholesta-7,24-dien-3ß-ol, the target molecules of SC5D in the sterol biosynthetic pathways, together constituted a mean of 10% of total sterols; in the conditional knockout mice these sterols constituted a mean of 56% of total sterols. The constitutive knockout mice had an even greater increase, with lathosterol and cholesta-7,24-dien-3ß-ol accounting for 80% of total sterols. In conclusion, the dominant presence of the 7-DHC precursors in hair of conditional animals and the lack of increased circulating D3 following exposure to UVR reflect attenuated production of the D3 photochemical precursor 7-DHC and, consequently, of D3 itself. These animals provide a useful new tool for investigating the role of D3 in UVR-induced physiological effects and, more broadly, for investigations of the cholesterol synthetic pathway in the skin and other targeted tissues.


Assuntos
Colecalciferol/sangue , Modelos Animais de Doenças , Queratinócitos/metabolismo , Erros Inatos do Metabolismo/metabolismo , Oxirredutases atuantes sobre Doadores de Grupo CH-CH/deficiência , Pele/metabolismo , Animais , Colecalciferol/biossíntese , Colesterol/metabolismo , Cruzamentos Genéticos , Desidrocolesteróis/metabolismo , Feminino , Cabelo/metabolismo , Heterozigoto , Estimativa de Kaplan-Meier , Queratinócitos/patologia , Queratinócitos/efeitos da radiação , Masculino , Erros Inatos do Metabolismo/sangue , Erros Inatos do Metabolismo/genética , Erros Inatos do Metabolismo/patologia , Camundongos Endogâmicos C57BL , Camundongos Knockout , Camundongos Transgênicos , Oxirredutases atuantes sobre Doadores de Grupo CH-CH/genética , Oxirredutases atuantes sobre Doadores de Grupo CH-CH/metabolismo , Gravidez , Distribuição Aleatória , Pele/patologia , Pele/efeitos da radiação , Raios Ultravioleta
9.
J Anim Physiol Anim Nutr (Berl) ; 101(2): 215-221, 2017 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-27421247

RESUMO

The link between UV light (sunlight) and endogenous cholecalciferol (vitamin D3 ) synthesis in the skin of humans has been known for more than a 100 years, since doctors for the first time successfully used UV light to cure rickets in children. Years later, it was shown that UV light also had a significant effect on the cholecalciferol status in the body of cattle. The cholecalciferol status in the body is measured as the plasma concentration of 25-hydroxycholecalciferol, which in cattle and humans is the major circulating metabolite of cholecalciferol. Very little is, however, known about the quantitative efficiency of UV light as a source of cholecalciferol in cattle nutrition and physiology. Hence, the aim of this study was to determine the efficiency of using UV light for increasing the plasma 25-hydroxycholecalciferol concentration in cholecalciferol-deprived cattle. Twelve cows deprived of cholecalciferol for 6 months were divided into three treatment groups and exposed to UV light for 30, 90 or 120 min/day during 28 days. UV-light wavelengths ranged from 280 to 415 nm and 30-min exposure to the UV light was equivalent to 60-min average summer-sunlight exposure at 56 °N. Blood samples were collected every 3-4 days and analysed for 25-hydroxycholecalciferol and cholecalciferol. Results showed that increasing the exposure time from 90-120 min/day did not change the slope of the daily increase in plasma 25-hydroxycholecalciferol. Hence, it appears that cholecalciferol-deprived dairy cattle are able to increase their plasma 25-hydroxycholecalciferol concentration by a maximum of 1 ng/ml/day from UV-light exposure.


Assuntos
Calcifediol/sangue , Bovinos/metabolismo , Colecalciferol/biossíntese , Pele/metabolismo , Raios Ultravioleta , Animais , Calcifediol/metabolismo , Relação Dose-Resposta à Radiação , Pigmentação , Pele/efeitos da radiação
10.
Domest Anim Endocrinol ; 59: 44-52, 2017 04.
Artigo em Inglês | MEDLINE | ID: mdl-27940098

RESUMO

In cattle, there are 2 significant forms of vitamin D: ergocalciferol (ERG) from fungi on roughage and cholecalciferol (CHO) from vitamin supplements or endogenous synthesis in the skin. The hypothesis of the present study is that vitamin D from the 3 sources is transported in different plasma fractions in the body. This is hypothesized to explain the lower efficiency of ERG compared to CHO in securing a sufficient plasma status of 25-hydroxyvitamin D and explain the inefficient excretion of dietary CHO into milk compared to endogenous CHO. Twenty vitamin D-depleted cows were assigned to 5 treatments: D2, housed indoor and fed 625-µg/d (25.000 IU) ERG; D3, housed indoor and fed 625-µg/d CHO; D2+D3, housed indoor and fed 625-µg/d ERG and 625-µg/d CHO; SUN, let out for daily pasture to facilitate CHO synthesis from sunlight; and D2+SUN, fed 625-µg/d ERG and let out for daily pasture. Blood samples were taken twice weekly and plasma fractionated by ultracentrifugation into 3 fractions: light lipoprotein (LLP), heavy lipoprotein (HLP), and protein and analyzed for content of ERG and CHO and their liver derived metabolites 25-hydroxyergocalciferol (25ERG) and 25-hydroxycholecalciferol (25CHO), respectively. Liver biopsies were taken on the last day of the study to asses gene expression related to vitamin D metabolism. During 4 wk of study, the vitamin D status in plasma increased to 19.3 to 22.8 ng/mL 25ERG in ERG-treated cows with the highest concentration in D2 (P ≤ 0.05) and to 25.0 to 33.4 ng/mL 25CHO in pasture or CHO-treated cows with the highest concentration in SUN (P ≤ 0.01). In plasma fractions, CHO was mainly found in the HLP fraction, whereas 25CHO was almost exclusively found in the protein fraction, probably due to its reported high binding affinity to vitamin D-binding protein. About 70% to 90% of 25ERG was found in the protein fraction and the remaining 25ERG was found in HLP, whereas ERG was found in both HLP and LLP fractions. In liver tissue, the expression of vitamin D-25-hydroxylase was lower in D2+D3 (P ≤ 0.05) and SUN (P ≤ 0.05) than that in the remaining groups, and the vitamin D receptor was expressed in the liver to a larger extent in D2+SUN than that in D2+D3 (P ≤ 0.05) and SUN (P ≤ 0.05). In conclusion, different plasma transport mechanisms may explain the lower physiological efficiency of ERG compared to CHO in securing the vitamin D status in plasma but do not explain the lower efficiency of synthetic CHO compared to endogenous CHO from sunlight or UV light in securing a high CHO content in milk.


Assuntos
Bovinos/sangue , Colecalciferol/sangue , Colecalciferol/metabolismo , Ergocalciferóis/sangue , Ergocalciferóis/metabolismo , Luz Solar , Animais , Colecalciferol/biossíntese , Feminino , Abrigo para Animais , Leite/química
11.
Photochem Photobiol Sci ; 15(7): 896-909, 2016 Jul 06.
Artigo em Inglês | MEDLINE | ID: mdl-27286277

RESUMO

Vitamin D3 photosynthesis in the skin is formulated as a set of reaction equations, including side-reactions to lumisterol, tachysterol and toxisterols, and the accompanying reverse reactions, isomerisation of previtamin D3 to vitamin D3 and photodegradation of vitamin D3. The solution of this set is given for the stationary irradiance spectrum. The effective action spectrum for the instantaneous vitamin D3 production changes shape as a function of exposure, and therefore, no single action spectrum can be used. We assessed the action spectrum for unexposed skin and for skin that has been exposed to 7.5 Standard Erythemal Doses (SED). We constructed two new estimates: (1) the RIVM action spectrum, based on absorption spectra, quantum yields and skin transmission spectra, and (2) the modified QUT action spectrum, which is adjusted for self-absorption and skin transmission. For previously unexposed skin, the modified QUT action spectrum gives a qualitatively similar, but larger estimate than the RIVM action spectrum. We have not been able to solve the lack of quantitative agreement between the vitamin D production estimates from the three action spectrum estimates (RIVM, modified QUT and CIE). All new action spectra have stronger emphasis on the short wavelengths than the CIE action spectrum. We showed that, for wavelengths larger than 300 nm, the bandwidth that was used in the experiment that formed the basis of the CIE action spectrum, gives a red-shift of about 1 nm. Generally, with the formation of previtamin D3, the return reaction to provitamin D3 limits the production of vitamin D3. After some exposure, the new action spectrum has negative values for the longer wavelengths in the UVB. For the RIVM action spectrum, this happens after 7.5 SED, for the modified QUT action spectrum already after 1.25 SED, and after 7.5 SED the net production rate is largely cancelled. Thus prolonged exposure of previously unexposed skin saturates vitamin D3 formation. For maximum vitamin D production after 1.25 SED, sunscreens should block wavelengths larger than 310 nm. Sunscreens that block only UVB could result in reduction in vitamin D production after prolonged exposure, or even a destruction of vitamin D that has just been formed.


Assuntos
Colecalciferol/química , Pele/efeitos da radiação , Luz Solar , Colecalciferol/análogos & derivados , Colecalciferol/biossíntese , Humanos , Processos Fotoquímicos , Teoria Quântica , Espectrofotometria Ultravioleta
12.
Anticancer Res ; 36(3): 1423-8, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26977046

RESUMO

BACKGROUND/AIM: The angular distribution of solar radiance and its spectral characteristics is required for the determination of vitamin D3 production in humans. MATERIALS AND METHODS: The vitamin D3 weighted exposure can be calculated by integrating the incident solar spectral radiance over all relevant parts of the human body. A novel instrument allowing simultaneous measurements of spectral radiance from more than 100 directions has been developed. A large solar simulator for controlled experiments is described. RESULTS: In summer it is relatively easy to obtain sufficient vitamin D because sun exposure times are short. In winter solstice vitamin D3 cannot be obtained with realistic clothing even if the exposure were extended to all daylight hours. CONCLUSION: Improved and controlled experiments to determine vitamin D3 production are required to assess the positive effects of solar UV radiation and to assess its natural variability.


Assuntos
Colecalciferol/biossíntese , Humanos , Estações do Ano , Luz Solar , Fatores de Tempo , Raios Ultravioleta
13.
Osteoporos Int ; 27(4): 1611-1617, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26630977

RESUMO

UNLABELLED: Evaluation of ultraviolet B index (UVBI) and its impact on vitamin D synthesis is important. We observed the maximum UVBI between 11 am and 1 pm. There was no increase in serum 25(OH)D levels following sun exposure during winter as the UVBI was significantly low, emphasizing the need for vitamin D supplementation during these months. INTRODUCTION: The amount of vitamin D3 synthesizing UVB irradiation (290-320 nm) reaching the earth's surface at different altitudes and seasons in different parts of India and it's impact on vitamin D synthesis has not been well studied. METHODS: The hourly UVB index (UVBI) from 10 am to 3 pm everyday for 12 months was measured by a solar meter in 4 different zones (North, Northeast, West and South) of the country. To study the impact of sun light exposure on vitamin D synthesis during winter, healthy school children aged 10-15 years were exposed to sunlight for a period of 30 min per day, between 11 am to 12 noon with 10 % body surface area, for 4 weeks. The main outcome measures were serum 25(OH)D, PTH, calcium, phosphate, and alkaline phosphatase levels before and after sun exposure. RESULTS: The mean UVBI was highest between 11 am and 1 pm throughout the year in all locations. The highest UVBI was recorded from the North zone (4.5 ± 2.7 µW/Cm(2)), while the least was recorded in the Northeast zone (2.1 ± 1.2 µW/Cm(2)). UVBI readings in the Northeast zone were consistently low throughout the year, while all the other three zones showed significant seasonal fluctuations. Surprisingly, we observed a significant decrease in serum 25(OH)D levels from baseline (6.3 ± 4.6 to 5.1 ± 2.7 ng/mL; p < 0.001) despite sun exposure. CONCLUSION: The mean UVBI was highest between 11 am and 1 pm throughout the year in all locations. No increase in the serum 25(OH)D levels was observed following sun exposure in winter, emphasizing the need for vitamin D supplementation during these months.


Assuntos
Colecalciferol/biossíntese , Estações do Ano , Luz Solar , Raios Ultravioleta , Adolescente , Criança , Feminino , Mapeamento Geográfico , Humanos , Índia/epidemiologia , Masculino , Exposição à Radiação , Instituições Acadêmicas , Vitamina D/análogos & derivados , Vitamina D/sangue , Deficiência de Vitamina D/sangue , Deficiência de Vitamina D/epidemiologia
14.
J Photochem Photobiol B ; 149: 224-9, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-26093795

RESUMO

BACKGROUND: Cholecalciferol (vitamin D3), produced in the skin by UVB irradiation (290-315nm) of 7-dehydrocholesterol, is metabolized in the liver into 25-hydroxyvitamin D [25(OH)D] which is a major circulating metabolite. AIM: To examine changes in serum concentrations of cholecalciferol and its metabolites after UVB exposure of different skin areas. METHODS: 21 healthy Caucasians (skin type II and III, aged 23-47years) were exposed to broadband UVB (290-320nm) and randomized to either exposure to one minimal erythema dose given as a single dose, or a suberythemic dose given for 3 subsequent days. The following areas were exposed: face and back of hands, upper half of the body and the whole body, respectively. Serum cholecalciferol and 25(OH)D were measured immediately before start and 24h after the 1st and last exposure, respectively. RESULTS: Subjects with whole body exposure had an average S-cholecalciferol increase per dose unit of 0.18ngml(-1)mJ(-1)cm(2), 0.95 CI: (0.16, 0.20), upper body treatment 0.13ngml(-1)mJ(-1)cm(2), 0.95 CI: (0.10, 0.15) and face and hands exposure 0.013ngml(-1)mJ(-1)cm(2), 0.95 CI: (-0.012, 0.037). The increase in cholecalciferol correlated positively to the UVB dose and skin erythema and negatively to body mass index (BMI) when controlling for other factors. Exposure of face and hands induces smaller cholecalciferol production in comparison with exposure of larger skin areas. CONCLUSION: Size of the exposed skin area, UVB dose, skin erythema and BMI were the major determinants for serum levels of skin synthesized cholecalciferol. Exposure of hands and face induces smaller cholecalciferol production in comparison with exposure of larger skin areas.


Assuntos
Índice de Massa Corporal , Superfície Corporal , Colecalciferol/biossíntese , Eritema/metabolismo , Pele/metabolismo , Raios Ultravioleta , Vitamina D/análogos & derivados , Adulto , Colecalciferol/sangue , Relação Dose-Resposta à Radiação , Eritema/sangue , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Distribuição Aleatória , Estações do Ano , Pele/efeitos da radiação , Vitamina D/biossíntese , Vitamina D/sangue , Adulto Jovem
15.
J Photochem Photobiol B ; 143: 38-43, 2015 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-25594723

RESUMO

BACKGROUND: Cholecalciferol is an essential steroid produced in the skin by solar ultraviolet B radiation (UVB 290-315nm). Skin production of cholecalciferol depends on factors affecting UVB flux, age and exposed skin area. PURPOSE: Serum cholecalciferol and 25-hydroxyvitamin D3 [25(OH)D3] concentrations were measured after UVB irradiation of 3 different skin areas to compare the skin capacity to produce vitamin D in different anatomic sites in the same individuals. METHOD: Ten voluntary Caucasians (skin photo type II & III, aged 48±12years (±SD)) were exposed to broadband UVB (280-320nm) between February and April. Hands and face, upper body and whole body were exposed to a suberythemic dose of UVB (median 101mJ/cm(2) (min 66, max 143)) (for 3 subsequent days 24h apart with a wash out period of about 3weeks (median 18days (min 11, max 25)) between the exposures of respective area. Serum concentrations of cholecalciferol and 25(OH)D3, were measured immediately before the first and 24h after the last dose of radiation. RESULTS: There was a significantly higher increase in serum cholecalciferol after UVB exposure of the two larger skin areas compared to face and hands, but no difference in increase was found between upper body and whole body exposures. CONCLUSION: Exposure of a larger skin area was superior to small areas and gave greater increase in both serum cholecalciferol and serum 25(OH)D3 concentrations. However, exposure of face and hands, i.e. only 5% of the body surface area, was capable of increasing serum concentrations of 25(OH)D3.


Assuntos
Calcifediol/biossíntese , Pele/metabolismo , Pele/efeitos da radiação , Raios Ultravioleta , Adulto , Idoso , Calcifediol/sangue , Colecalciferol/biossíntese , Colecalciferol/sangue , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
16.
Mol Med Rep ; 11(4): 3143-7, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25501030

RESUMO

Chronic myeloid leukemia (CML) is a myeloproliferative disease characterized by the presence of the BCR­ABL1 fusion gene, a constitutively active, oncogenic tyrosine kinase that is responsible for the clinical features of CML. Tyrosine kinase inhibitors, such as imatinib, have markedly altered the treatment of CML. However, tyrosine kinase inhibitors are associated with side effects on bone metabolism, in adult and pediatric patients. Vitamin D3 is involved in the complex cycle of bone remodeling, therefore the present study aimed to investigate the influence of imatinib on vitamin D3 metabolism in the HaCaT human keratinocyte cell line, using commercially available enzyme assays. Imatinib was shown to significantly reduce the production of calcidiol and calcitriol. Based on interaction studies of imatinib with the cytochrome P450 (CYP450) inhibitors VID400 and ketoconazole, it is proposed that imatinib may interfere with the vitamin D3 cascade due to its metabolism by CYP27B1, which is involved in vitamin D3 metabolism.


Assuntos
Antineoplásicos/farmacologia , Benzamidas/farmacologia , Colecalciferol/biossíntese , Queratinócitos/efeitos dos fármacos , Queratinócitos/metabolismo , Piperazinas/farmacologia , Inibidores de Proteínas Quinases/farmacologia , Pirimidinas/farmacologia , Calcitriol/biossíntese , Linhagem Celular , Humanos , Mesilato de Imatinib , Redes e Vias Metabólicas/efeitos dos fármacos
17.
J Biomed Mater Res A ; 103(7): 2280-8, 2015 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-25369149

RESUMO

UV-activated 7-dehydrocholesterol (7-DHC) has been successfully used as a biocompatible coating for titanium (Ti) implants producing active vitamin D with positive effect on osteoblast differentiation. Since an osseointegrating implant must promote bone formation while delay resorption, here we determine the effect of this coating on the pre-osteoclast cell line RAW 264.7. Moreover, D3 synthesis was optimized by (1) the supplementation with VitE of the 7-DHC coating to reduce 7-DHC oxidation and (2) the addition of an incubation step (48 h at 23°C) after UV-irradiation to favor isomerization. In vitro results with RAW264.7 cells showed no cytotoxic effect of the coatings and a significant decrease of osteoclastogenesis. Indeed, TRAP immunostaining suggested an inhibition of Trap-positive multinucleated cells and the mRNA levels of different phenotypic, fusion, and activity markers were reduced, particularly with 7-DHC:VitE. In conclusion, we demonstrate an improvement of the D3 synthesis from UV-activated 7-DHC when combined with VitE and show that these implants inhibit osteoclastogenesis in vitro.


Assuntos
Colecalciferol/biossíntese , Desidrocolesteróis/metabolismo , Próteses e Implantes , Titânio , Raios Ultravioleta , Animais , Linhagem Celular , Técnicas In Vitro , Macrófagos/metabolismo , Macrófagos/efeitos da radiação , Camundongos
18.
J Anim Physiol Anim Nutr (Berl) ; 99(2): 391-403, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-24810567

RESUMO

Many amphibian species are dependent on ex situ conservation interventions for their long-term persistence. However, projects have been jeopardised by husbandry issues involving poor calcium metabolism and nutritional metabolic bone disease (NMBD). Healthy calcium metabolism requires appropriate dietary calcium content and access to vitamin D3 . In many animals, vitamin D3 can be photobiosynthesised in skin exposed to UVB radiation, as well as extracted from the diet, but the extent of vitamin D3 photobiosynthesis in amphibians is poorly known. Additionally, prey insects for captive amphibians are deficient in calcium and calcium content must be artificially increased, but the effects of different levels of augmentation and their interaction with UVB exposure are also little understood. We fed captive fire-bellied toads (Bombina orientalis) with crickets augmented to contain 5% and 10% calcium and housed them with and without UVB exposure. Despite additional dietary vitamin D3 supplementation, we found that toads exposed to UVB radiation exhibited significantly higher serum vitamin D3 levels, indicating that this species may partly rely on photobiosynthesis sources of vitamin D3 . These data are the first to show a direct link between UVB exposure and serum vitamin D3 in an amphibian. We found significant positive effects of UVB exposure and 10% dietary calcium content on skeletal structure, as well as complex interactions between treatments. We also found UVB radiation exposure resulted in more rapid natural coloration acquisition. Together, this indicates that standard calcium plus vitamin D3 supplementation methods may not fully substitute for UVB exposure and for increased feeder insect calcium content. This may have implications for the success of ex situ amphibian conservation, as well as for the welfare of captive amphibians in general. Our data lend support for the provision of UVB radiation for captive, basking amphibians.


Assuntos
Anuros/fisiologia , Desenvolvimento Ósseo/efeitos dos fármacos , Cálcio na Dieta/farmacologia , Colecalciferol/sangue , Pigmentos Biológicos/metabolismo , Raios Ultravioleta , Ração Animal , Criação de Animais Domésticos , Animais , Desenvolvimento Ósseo/efeitos da radiação , Colecalciferol/biossíntese , Gryllidae
19.
Invest Ophthalmol Vis Sci ; 55(4): 2140-7, 2014 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-24576880

RESUMO

PURPOSE: Vitamin D3 is a secosteroid mainly synthesized from the conversion of the skin precursor 7-dehydrocholesterol (7DHC) to vitamin D3 by ultraviolet (UV) B sunlight. Extrarenal synthesis of vitamin D3 has been reported in many tissues and cells, including barrier sites. This study characterizes the expression of components of vitamin D3 signaling in human ocular barrier cells. METHODS: Primary human scleral fibroblasts (HSF), human corneal endothelial (HCEC-12), nonpigmented ciliary body epithelial (ODM-2), and adult retinal pigment epithelial (ARPE-19) cell lines were analyzed for the expression of vitamin D receptor (VDR), the vitamin D3 activating enzymes 1α-hydroxylase (CYP27B1), 25-hydroxylases (CYP27A1 and CYP2R1), the vitamin D3 inactivating enzyme 24-hydroxylase (CYP24A1), and the endocytic receptors cubilin and megalin using a combination of RT-PCR, immunocytochemistry, and enzyme immunoassay (EIA). RESULTS: The HSF, HCEC-12, ODM-2, and ARPE-19 express mRNA and protein for all vitamin D3 synthesizing and metabolizing components. The cell types tested, except HSF, are able to convert inactive 25-hydroxyvitamin D3 (25[OH]D3) into active 1,25-hydroxyvitamin D3 (1,25[OH]2D3). CONCLUSIONS: This novel study demonstrated that ocular barrier epithelial cells express the machinery for vitamin D3 and can produce 1,25(OH)2D3. We suggest that vitamin D3 might have a role in immune regulation and barrier function in ocular barrier epithelial cells.


Assuntos
25-Hidroxivitamina D3 1-alfa-Hidroxilase/genética , Colecalciferol/biossíntese , Epitélio Posterior/metabolismo , Regulação da Expressão Gênica , RNA Mensageiro/genética , Epitélio Pigmentado da Retina/metabolismo , Esclera/metabolismo , 25-Hidroxivitamina D3 1-alfa-Hidroxilase/biossíntese , Linhagem Celular , Epitélio Posterior/citologia , Humanos , Técnicas Imunoenzimáticas , Imuno-Histoquímica , Epitélio Pigmentado da Retina/citologia , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Esclera/citologia
20.
Photochem Photobiol Sci ; 13(3): 521-30, 2014 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24352228

RESUMO

Polysulphone (PS) dosimetry is a well-known technique broadly used to assess the erythemally effective solar UV dose received by anatomical sites (personal exposure). We investigate the capability of PS dosimetry to convert doses absorbed by PS badges into biologically effective solar UV exposures taking as examples two relevant effects for human skin: erythema induction and pre-vitamin D3 production. PS calibration curves for erythemal and pre-vitamin D3 were distinctly determined by using an empirical relationship between the biologically effective UV exposures and the PS absorbance change. This relationship is parameterized by a coefficient, distinct for each of the two considered biological effects, multiplying the same cubic polynomial function. It is shown how the multiplying coefficient is related to the ratio between the biologically effective and the PS weighted irradiances which is the prevailing factor affecting the accuracy of the calibration and, consequently, the capability of PS films for measuring biologically effective solar UV exposures. The points addressed in this paper can be extended to other biological effects of interest whose action spectra have some similarity with the PS film response.


Assuntos
Dosimetria Fotográfica , Polímeros/efeitos da radiação , Pele/efeitos da radiação , Sulfonas/efeitos da radiação , Luz Solar , Raios Ultravioleta , Absorção , Algoritmos , Calibragem , Colecalciferol/biossíntese , Relação Dose-Resposta à Radiação , Eritema/fisiopatologia , Humanos , Modelos Lineares , Modelos Biológicos , Ozônio , Polímeros/química , Pele/metabolismo , Pele/fisiopatologia , Sulfonas/química
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