scholarly journals Vitamin D Synthesis Following a Single Bout of Sun Exposure in Older and Younger Men and Women

Nutrients ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 2237 ◽  
Author(s):  
Jenna R. Chalcraft ◽  
Linda M. Cardinal ◽  
Perry J. Wechsler ◽  
Bruce W. Hollis ◽  
Kenneth G. Gerow ◽  
...  
Keyword(s):  
Older Adults ◽  
Vitamin D ◽  
Vitamin D3 ◽  
Ex Vivo ◽  
Sun Exposure ◽  
Vitamin D Metabolites ◽  
Post Exposure ◽  
Non Melanoma Skin Cancer ◽  
Younger Men ◽  
Cutaneous Synthesis

Older adults are frequently cited as an at-risk population for vitamin D deficiency that may in part be due to decreased cutaneous synthesis, a potentially important source of cholecalciferol (vitamin D3). Previous studies found that cutaneous D3 production declines with age; however, most studies have been conducted ex vivo or in the photobiology lab. The purpose of this study was to characterize the response of vitamin D metabolites following a 30-min bout of sun exposure (15-min each to the dorsal and ventral sides) at close to solar noon in younger and older adults. Methods: 30 healthy individuals with skin type II/III were recruited; a younger cohort, aged 20–37 (n = 18) and an older cohort (n = 12), age 51–69 years. Exposure was at outer limits of sensible sun exposure designed to enhance vitamin D synthesis without increasing risk of photo ageing and non-melanoma skin cancer. Serum D3 concentration was measured at baseline, 24, 48 and 72 h post-exposure. Serum 25(OH)D was measured at baseline and 72 h post-exposure plus 168 h post-exposure in the older cohort. Results: D3 increased in response to sun exposure (time effect; p = 0.002) with a trend for a difference in D3 between cohorts (time*group; p = 0.09). By regression modeling of continuous data, age accounted for 20% of the variation in D3 production. D3 production decreased by 13% per decade. Despite changes in D3, however, serum 25(OH)D did not change from baseline to 72 or 168 h post exposure (p > 0.10). Conclusions: Serum D3 concentration increased significantly in response to outdoor sun exposure in younger and older adults. While ageing may dampen cutaneous synthesis, sunlight exposure is still a significant source of vitamin D3.

scholarly journals Seasonal Variation in Vitamin D in Association with Age, Inflammatory Cytokines, Anthropometric Parameters, and Lifestyle Factors in Older Adults

2017 ◽  
Vol 2017 ◽  
pp. 1-14 ◽  
Author(s):  
Leticia Elizondo-Montemayor ◽  
Elena C. Castillo ◽  
Carlos Rodríguez-López ◽  
José R. Villarreal-Calderón ◽  
Merit Gómez-Carmona ◽  
...  
Keyword(s):  
Older Adults ◽  
Vitamin D ◽  
Seasonal Variation ◽  
Vitamin D Deficiency ◽  
High Probability ◽  
Sun Exposure ◽  
Serum Levels ◽  
Lifestyle Factors ◽  
Anthropometric Parameters ◽  
Healthy Older Adults

Vitamin D deficiency is present even in sunny regions. Ageing decreases pre-vitamin D production in the skin and is associated with altered cytokine profile. We performed a multivariate analysis considering lifestyle factors, anthropometric, and inflammatory markers according to seasonal variation in Mexican healthy older adults. The same cohort was followed during 12 months. Vitamin D deficiency/insufficiency was found in 91.3% of the subjects despite living in appropriate latitude (25°40′0″N). 25(OH)D levels remained below <30 ng/mL through all seasons. Vitamin D deficiency did not correlate to sun exposure or dietary intake. Gender was the strongest associated factor, explaining a variance of 20%. Waist circumference (WC) greater than 88 cm was a risk factor for vitamin D deficiency. Age (>74 years) combined with WC (>88 cm) and BMI (>32.7) showed a high probability (90%) of vitamin D deficiency. Remarkably, an increase in one centimeter in WC decreased 25(OH)D by 0.176 ng/mL, while an increase in one point BMI decreased 25(OH)D by 0.534 ng/mL. A cutoff point of 74 years of age determined probability of vitamin D hipovitaminosis. Vitamin D deficiency was correlated with TNF-αserum levels, possibly increasing the susceptibility of older adults to a proinflammatory state and its related diseases.

Does vitamin D prevent radiotherapy-induced toxicity?

2019 ◽  
Vol 44 (5) ◽  
pp. 575-577
Author(s):  
Yasemin Benderli Cihan
Keyword(s):  
Vitamin D ◽  
Immune Response ◽  
Cancer Treatment ◽  
Vitamin D3 ◽  
Vitamin D Metabolites ◽  
Cytokine Levels ◽  
Anti Inflammatory ◽  
Positive Effect

AbstractVitamin D is known as the bone hormone, it is also know that it has effects on cancer because of its anti-inflammatory and immunomodulatory characteristics and its effects on cytokine levels. It is seen that vitamin D use together with radiotherapy can have a positive effect on cancer treatment. It should be investigated whether toxicities due to radiation is prevented by vitamin D metabolites’ increasing the induction of immunomodulator cells and the capacities of immune response cells. Use of 1,25[OH]2 Vitamin D3 analogs as an adjuvant immunomodulator for patients receiving radiotherapy should be evaluated. There is a need for studies to be done in this regard.

Stimulation of 24R,25-dihydroxyvitamin D3 synthesis by metabolites of vitamin D3

1983 ◽  
Vol 245 (4) ◽  
pp. E359-E364 ◽  
Author(s):  
G. S. Reddy ◽  
G. Jones ◽  
S. W. Kooh ◽  
D. Fraser ◽  
H. F. DeLuca
Keyword(s):  
Vitamin D ◽  
Vitamin D3 ◽  
The Other ◽  
Hydroxyl Group ◽  
Vitamin D Metabolites ◽  
Structural Requirements ◽  
Dihydroxyvitamin D3 ◽  
Hydroxylated Metabolites ◽  
Perfusion Period ◽  
Stimulation Of

Previously we have shown that the isolated perfused kidney from vitamin D-deficient rats converts [3H]25(OH)D3 into [3H]1 alpha,25(OH)2D3. When certain vitamin D metabolites were added to perfusate the same kidney began to synthesize [3H]24R,25(OH)2D3. In this study we investigated the structural requirements of the vitamin D molecule necessary to stimulate synthesis of [3H]24R,25(OH)2D3 in a 1-hydroxylating kidney. Kidneys were perfused with tracer [3H]25(OH)D3 (450 pM) alone and in the presence of a variety of hydroxylated metabolites and fluorinated analogues of vitamin D3 at concentrations of 450 pM to 25 microM. Tracer [3H]25(OH)D3 alone resulted in synthesis of only [3H]1 alpha,25(OH)2D3 during the 6-h perfusion period. 25-Hydroxylated metabolites [25(OH)D3, 25 nM; 1 alpha,25(OH)2D3, 25 nM; 24R,25(OH)2D3, 25 nM; 24(F)2,25(OH)D3, 50 nM] stimulated [3H]24R,25(OH)2D3 production at 2 h of perfusion. On the other hand, analogues without the 25-hydroxyl group [D3; 1 alpha(OH)D3; 25(F)D3; 1 alpha(OH),25(F)D3; 1 alpha(F)D3; 1 beta(F)D3]; did not stimulate [3H]24R,25(OH)2D3 synthesis. We conclude that the 25-hydroxyl group is an essential determinant of 24-hydroxylation.

scholarly journals Determination of Vitamin D and Its Metabolites in Human Brain Using an Ultra-Pressure LC–Tandem Mass Spectra Method

2019 ◽  
Vol 3 (7) ◽  
Author(s):  
Xueyan Fu ◽  
Gregory G Dolnikowski ◽  
William B Patterson ◽  
Bess Dawson-Hughes ◽  
Tong Zheng ◽  
...  
Keyword(s):  
Vitamin D ◽  
Corpus Callosum ◽  
Human Brain ◽  
Vitamin D3 ◽  
Temporal Cortex ◽  
National Development ◽  
Brain Regions ◽  
Accurate Information ◽  
Vitamin D Metabolites

ABSTRACTBackgroundLow serum total 25-hydroxyvitamin D3 [25(OH)D3] concentrations have been associated with cognitive impairment. However, it is unclear if serum 25(OH)D3 concentrations are a valid indicator of the concentrations of vitamin D and its metabolites in human brain.ObjectivesThe aim of this study was to develop and validate a method to quantify vitamin D3, 25(OH)D3, and 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] in human brain.MethodsThe assay developments were performed using porcine brains. Liquid extraction was used in homogenized samples (∼0.1 g each) prior to analysis by LC-MS/MS with electrospray ionization following derivatization with 4-phenyl-1,2,4-triazoline-3,5-dione. This method was then applied to the determination of vitamin D and its metabolites in a whole human brain obtained from the National Development and Research Institutes.ResultsThe method showed good linearity of vitamin D3, 25(OH)D3, and 1,25(OH)2D3 over the physiological range (R2 = 0.9995, 0.9968, and 0.9970, respectively). The lowest detection limit for vitamin D3, 25(OH)D3, and 1,25(OH)2D3 in porcine brain was 25, 50 and 25 pg/g, respectively. The method was successfully applied to the determination of vitamin D3 and its metabolites in the prefrontal cortex, middle frontal cortex, middle temporal cortex, cerebellum, corpus callosum, medulla, and pons of a human brain. All analyzed human brain regions contained 25(OH)D3, with corpus callosum containing 334 pg/g compared with 158 pg/g in cerebellum. 1,25(OH)2D3 was only detected in prefrontal and middle frontal cortices at a very low level. No vitamin D3 was detected in any examined areas of this single human brain.ConclusionsTo the best of our knowledge, this study is the first report of the measurement of concentrations of vitamin D metabolites in human brain. This validated method can be applied to postmortem studies to obtain accurate information about the presence and role of vitamin D and its metabolites in human brain and neurodegenerative diseases.

Renal effect of vitamin D metabolites: evidence for the essential role of the 25(OH) group

1983 ◽  
Vol 244 (6) ◽  
pp. F674-F678 ◽  
Author(s):  
M. M. Friedlaender ◽  
Z. Kornberg ◽  
H. Wald ◽  
M. M. Popovtzer
Keyword(s):  
Vitamin D ◽  
Vitamin D3 ◽  
Essential Role ◽  
Fractional Excretion ◽  
Vitamin D Metabolites ◽  
Group 2 ◽  
Fractional Excretion Of Phosphate ◽  
Group 1

The effects of 1 alpha (OH)vitamin D3 [1 alpha (OH)D3] and 24,25(OH)2vitamin D3 [24,25(OH)2D3] on the phosphaturic action of parathyroid hormone (PTH) were studied in two groups of parathyroidectomized (PTX) rats. In group 1, PTX PTH-infused rats received intravenous 1 alpha (OH)D3, and in group 2, PTX PTH-infused rats received intravenous 24,25(OH)2D3. PTX PTH-infused rats served as controls. The effects of both vitamin D metabolites on renal PTH-activated adenylate cyclase (AC) were studied in vitro. In group 1, PTH increased fractional excretion of phosphate (CP/CIn) from 0.045 +/- 0.012 (+/- SE) to 0.263 +/- 0.011 (P less than 0.005). 1 alpha (OH)D3 failed to influence this response. In group 2, PTH increased CP/CIn from 0.055 +/- 0.008 to 0.289 +/- 0.027 (P less than 0.005). 24,25(OH)2D3 reduced the PTH-induced rise in CP/CIn from 0.289 +/- 0.027 to 0.192 +/- 0.021 (P less than 0.01) and decreased the urinary excretion of adenosine 3',5'-cyclic monophosphate. In vitro, 24,25(OH)2D3 blunted the PTH-activated AC, whereas 1 alpha (OH)D3 had no effect. These results show that 24,25(OH)D3, similar to two other 25(OH) metabolites of vitamin D-25(OH)vitamin D3 and 1,25(OH)2vitamin D3-suppresses the phosphaturic action of PTH, whereas 1 alpha(OH)D3, which is devoid of a 25(OH) group, lacks this effect. This suggests that a 25(OH) group is a prerequisite for the antiphosphaturic effect of vitamin D, whereas the 1 alpha (OH) group is not essential for this action.

scholarly journals Controversies regarding the relation between solar radiation, cutaneous synthesis of vitamin D and the development of malignant melanoma

2015 ◽  
Vol 18 (1) ◽  
pp. 24-29
Author(s):  
Corina-Daniela Ene ◽  
◽  
Amalia-Elena Anghel ◽  
Alina Muşetescu ◽  
Ilinca Nicolae ◽  
...  
Keyword(s):  
Vitamin D ◽  
Skin Cancer ◽  
Malignant Melanoma ◽  
Cellular Proliferation ◽  
Experimental Studies ◽  
Sun Exposure ◽  
Serum Levels ◽  
The Body ◽  
Melanoma Metastasis ◽  
Cutaneous Synthesis

The relation between sun exposure, vitamin D synthesis and skin cancer is a complex one. Radiations from the sun stimulate the cutaneous vitamin D synthesis, one way, and promote the development of the skin cancer on the other way. A lot of epidemiologic and experimental studies revealed contradictory results regarding the relation between vitamin D and malignant melanoma. The vitamin D deficiency, accurate biochemical indicator of the vitamin D status in the body, could be implicated in promoting metastasis of the malignant melanoma by activation of the cellular proliferation, stimulation of the neutrophils chemotaxis and promoting angiogenesis. Identification of therapeutic strategies to normalise serum levels of the 25-OH vitamin D3 could represent useful tools in preventing melanoma metastasis.

scholarly journals Vitamin D, Depressive Symptoms, and Covid-19 Pandemic

2021 ◽  
Vol 15 ◽  
Author(s):  
Gilciane Ceolin ◽  
Giulia Pipolo Rodrigues Mano ◽  
Natália Schmitt Hames ◽  
Luciana da Conceição Antunes ◽  
Elisa Brietzke ◽  
...  
Keyword(s):  
Vitamin D ◽  
Depressive Symptoms ◽  
Vitamin D3 ◽  
Tryptophan Hydroxylase ◽  
Biological Effects ◽  
Active Form ◽  
Sun Exposure ◽  
Monoamine Oxidase A ◽  
Distance Measures ◽  
The Brain

Graphical AbstractRole of vitamin D in the development of depressive symptoms. The synthesis of vitamin D from sunlight is impaired by lockdown and social distance measures imposed by the governments around the world during COVID-10 pandemic. Endogenous vitamin D synthesis initiates in the skin when 7-dehydrocholesterol (7-DHC) is converted in pre-vitamin D3 and then vitamin D3 [25(OH)D3]. It is transported through blood circulation by the vitamin D binding protein (VDBP) to the liver, the kidney, and the brain, where can be converted in its the active form [1,25(OH)2D3]. In the brain, the biological effects of 1,25(OH)2D3 are largely mediated by vitamin D receptor (VDR) through genomic mechanisms, which influence several aspects of serotonin metabolism, such as increasing serotonin synthesis by induction of the tryptophan hydroxylase 2 (TPH2) gene expression; influencing the expression of serotonin reuptake transporter (SERT) and the levels of monoamine oxidase-A (MAO-A), responsible to serotonin catabolism; and indirectly may regulate the synthesis of melatonin that improve the circadian rhythm. This mechanism can be impaired during social isolation and consequent reduction of vitamin D due to low sun exposure during the pandemic, which could contribute to the development of depressive symptoms.

scholarly journals Super-doses of dietary vitamin D3 intake in aged laying hens illustrates limitation of 24,25-dihydroxycholecalciferol conversion

2021 ◽  
Author(s):  
Matthew F. Warren ◽  
Pete M. Pitman ◽  
Dellila D. Hodgson ◽  
Kimberly A. Livingston
Keyword(s):  
Vitamin D ◽  
Vitamin D3 ◽  
Laying Hens ◽  
Dietary Vitamin ◽  
Plasma Vitamin ◽  
Vitamin D Metabolites ◽  
Vitamin D Status ◽  
Blood Calcium ◽  
Reduce Risk ◽  
Dietary Vitamin D

Background: Humans take vitamin D supplements to reduce risk of vitamin D deficiency and reduce the risk of osteoporosis. However, it is unclear how dietary super-dose (10,000x greater than requirement) can affect vitamin D status in aged animals. Aged laying hens could potentially be a model to compare with women in peri- or postmenopausal stages of life because their bone health is physiologically taxed from egg production and they are highly susceptible to osteoporosis. Objective: We investigated dietary super-dose impacts of cholecalciferol (vitamin D3) on vitamin D status in aged laying hens in production. Methods: Forty-eight 68-wk old Hy-Line Brown laying hens were individually housed in cages with eight hens per dietary treatment for eleven weeks. Hens were randomly assigned to one of six groups of dietary vitamin D3 supplementation and fed ad libitum. Supplementation levels were 400 (recommended dosage for hens), 800, 7,400, 14,000, 20,000, and 36,000 IU D3/kg of feed. At termination of the study, all hens were euthanized and we collected blood, feces, and tibia and humerus bones. Ionized (free) blood calcium, fecal calcium, bone calcium, and plasma vitamin D metabolites were measured. Results: We did not discern any dietary effects in tissue and fecal calcium. We observed that increasing dietary vitamin D3 increased plasma vitamin D3, 25-hydroxycholecalciferol, and 24,25-dihydroxycholecalciferol concentrations (p < 0.0001 for all 3 metabolites). We also observed super-dose fed hens had decreased kidney 24-hydroxylase expression (p = 0.0006). Conclusions: Although dietary vitamin D3 super-doses did not affect calcium status in our aged laying hens, it is possible there is an age-related effect of not being as sensitive to vitamin D efficacy. We suggest future research should explore how 24-hydroxylation mechanisms are affected by vitamin D supplementation. Further understanding of 24-hydroxylation can help ascertain ways to reduce risk of vitamin D toxicity.

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