Vitamin D status and metabolism in an ovine pregnancy model: effect of long-term, high-altitude hypoxia

Vitamin D status increases during healthy mammalian pregnancy, but the molecular determinants remain uncharacterized. The first objective of this study was to determine the effects of pregnancy, and the second objective was to examine the role of chronic hypoxia on vitamin D status and metabolism in an ovine model. We analyzed the plasma levels of cholecalciferol, 25-OH-D, and 1α,25-(OH)2D in nonpregnant ewes, near-term pregnant ewes, and their fetuses exposed to normoxia (low altitude) or hypoxia (high-altitude) for 100 days. Hypoxic sheep had increased circulating levels of 25-OH-D and 1α,25-(OH)2D compared with normoxic sheep. Hypoxia increases in 25-OH-D were associated with increased expression of renal 25-hydroxylases CYP2R1 and CYP2J. Pregnancy did not increase further the plasma levels of 25-OH-D, but it significantly increased those of the active metabolite, 1α,25-(OH)2D, in both normoxic and hypoxic ewes. Increased bioactivation of vitamin D correlated with increased expression of the vitamin D-activating enzyme CYP27b1 and decreased expression of the inactivating enzyme CYP24a1 in maternal kidneys and placentas. Hypoxia increased parathyroid hormone levels and further increased renal CYP27b1. Pregnancy and hypoxia decreased the expression of vitamin D receptor (VDR) in maternal kidney and lung, with opposite effects on placental VDR. We conclude that ovine pregnancy is a model of increased vitamin D status, and long-term hypoxia further improves vitamin D status due to pregnancy- and hypoxia-specific regulation of VDR and metabolic enzymes.

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Does vitamin D supplementation prevent SARS-CoV-2 infection in military personnel? Review of the evidence

BMJ Military Health ◽

10.1136/bmjmilitary-2020-001686 ◽

2021 ◽

pp. bmjmilitary-2020-001686

Author(s):

Iain T Parsons ◽

R M Gifford ◽

M J Stacey ◽

L E Lamb ◽

M K O'Shea ◽

...

Keyword(s):

Vitamin D ◽

Vitamin D Supplementation ◽

Vitamin D Status ◽

Military Studies ◽

Vitamin D Receptors ◽

Area Of Interest ◽

Military Populations ◽

Tract Infections ◽

Recruit Training

For most individuals residing in Northwestern Europe, maintaining replete vitamin D status throughout the year is unlikely without vitamin D supplementation and deficiency remains common. Military studies have investigated the association with vitamin D status, and subsequent supplementation, with the risk of stress fractures particularly during recruit training. The expression of nuclear vitamin D receptors and vitamin D metabolic enzymes in immune cells additionally provides a rationale for the potential role of vitamin D in maintaining immune homeostasis. One particular area of interest has been in the prevention of acute respiratory tract infections (ARTIs). The aims of this review were to consider the evidence of vitamin D supplementation in military populations in the prevention of ARTIs, including SARS-CoV-2 infection and consequent COVID-19 illness. The occupational/organisational importance of reducing transmission of SARS-CoV-2, especially where infected young adults may be asymptomatic, presymptomatic or paucisymptomatic, is also discussed.

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The impact of vitamin D status on changes in bone mineral density during treatment with bisphosphonates and after discontinuation following long-term use in post-menopausal osteoporosis

BMC Musculoskeletal Disorders ◽

10.1186/1471-2474-8-3 ◽

2007 ◽

Vol 8 (1) ◽

Cited By ~ 40

Author(s):

Andrew Deane ◽

Leonor Constancio ◽

Ignac Fogelman ◽

Geeta Hampson

Keyword(s):

Bone Mineral Density ◽

Vitamin D ◽

Bone Mineral ◽

Vitamin D Status ◽

Mineral Density ◽

Post Menopausal Osteoporosis ◽

Post Menopausal ◽

The Impact ◽

Menopausal Osteoporosis

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The Potential Role of Vitamin D Enhanced Foods in Improving Vitamin D Status

Nutrients ◽

10.3390/nu3121023 ◽

2011 ◽

Vol 3 (12) ◽

pp. 1023-1041 ◽

Cited By ~ 71

Author(s):

Louise O’Mahony ◽

Magdalena Stepien ◽

Michael J. Gibney ◽

Anne P. Nugent ◽

Lorraine Brennan

Keyword(s):

Vitamin D ◽

Potential Role ◽

Vitamin D Status

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Assessment of Vitamin D Status in Patients Suffering from Uncomplicated Malaria in a Health Center in the District of Abidjan (Côte d’Ivoire)

International Journal of Biochemistry Research & Review ◽

10.9734/ijbcrr/2021/v30i830282 ◽

2021 ◽

pp. 10-17

Author(s):

Brice Kouakou Bla ◽

Alexis Gnogbo Bahi ◽

Juliana Mensah-Akaki ◽

Souleymane Méité ◽

Françis Adou Yapo ◽

...

Keyword(s):

Vitamin D ◽

Parasite Density ◽

Uncomplicated Malaria ◽

Parasite Species ◽

Complete Blood Count ◽

Vitamin D Status ◽

25 Oh Vitamin D ◽

Stimulation Of

Aims: The pathophysiology of Plasmodium falciparum infection is most often associated with anemia and immune deficiency. Given the important role of vitamin D in the synthesis of hemoglobin and in the stimulation of the immune system, it would be essential to assess the vitamin D status of patients with malaria in order to improve the quality of treatment management. Methodology: A thick drop and a blood smear were used to determine parasite density and parasite species respectively. The complete blood count was performed using an automated analyzer labelled Sysmex XN 1000i. Biochemical parameters such as calcium and phosphorus were determined using the Cobas C311 Hitachi. The Vidas was used to determine the concentrations of 25 (OH) -vitamin D. Results: The results showed a decrease in 25 (OH) -vitamin D concentrations in relation to the parasite density and anemia observed in patients with uncomplicated malaria. Conclusion: Vitamin D status in patients with uncomplicated malaria could represent an essential biomarker in the monitoring of antimalarial treatment.

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(205) The role of clinical pain in the association between vitamin D status and sleep quality among adults with knee osteoarthritis

Journal of Pain ◽

10.1016/j.jpain.2014.01.112 ◽

2014 ◽

Vol 15 (4) ◽

pp. S27

Author(s):

M. Petrov ◽

T. Glover ◽

B. Goodin ◽

L. Bradley ◽

R. Fillingim

Keyword(s):

Vitamin D ◽

Sleep Quality ◽

Knee Osteoarthritis ◽

Vitamin D Status ◽

Clinical Pain

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Vitamin D Status Impacts Genital Mucosal Immunity and Markers of HIV-1 Susceptibility in Women

Nutrients ◽

10.3390/nu12103176 ◽

2020 ◽

Vol 12 (10) ◽

pp. 3176

Author(s):

Sharon M. Anderson ◽

Andrea R. Thurman ◽

Neelima Chandra ◽

Suzanne S. Jackson ◽

Susana Asin ◽

...

Keyword(s):

Vitamin D ◽

Reproductive Tract ◽

Serum Vitamin ◽

Female Reproductive Tract ◽

High Dose ◽

Vitamin D Status ◽

Serum Vitamin D ◽

Vitamin D Levels ◽

Hiv 1

While vitamin D insufficiency is known to impact a multitude of health outcomes, including HIV-1, little is known about the role of vitamin D-mediated immune regulation in the female reproductive tract (FRT). We performed a pilot clinical study of 20 women with circulating 25(OH)D levels <62.5 nmol/L. Participants were randomized into either weekly or daily high-dose oral vitamin D supplementation groups. In addition to serum vitamin D levels, genital mucosal endpoints, including soluble mediators, immune cell populations, gene expression, and ex vivo HIV-1 infection, were assessed. While systemic vitamin D levels showed a significant increase following supplementation, these changes translated into modest effects on the cervicovaginal factors studied. Paradoxically, post-supplementation vitamin D levels were decreased in cervicovaginal fluids. Given the strong correlation between vitamin D status and HIV-1 infection and the widespread nature of vitamin D deficiency, further understanding of the role of vitamin D immunoregulation in the female reproductive tract is important.

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Characteristics of carbonaceous aerosols derived from long-term high-resolution measurements at a high-altitude site in the central Himalayas: radiative forcing estimates and role of meteorology and biomass burning

Environmental Science and Pollution Research ◽

10.1007/s11356-020-11579-1 ◽

2020 ◽

Author(s):

Priyanka Srivastava ◽

Manish Naja

Keyword(s):

High Resolution ◽

High Altitude ◽

Biomass Burning ◽

Radiative Forcing ◽

Carbonaceous Aerosols ◽

Central Himalayas

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High altitude-induced changes in alpha1-adrenergic receptors and Ins(1,4,5)P3 responses in cerebral arteries

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.1997.272.2.r669 ◽

1997 ◽

Vol 272 (2) ◽

pp. R669-R674 ◽

Cited By ~ 15

Author(s):

N. Ueno ◽

Y. Zhao ◽

L. Zhang ◽

L. D. Longo

Keyword(s):

High Altitude ◽

Adrenergic Receptor ◽

Cerebral Arteries ◽

Control Value ◽

Density Values ◽

High Altitude Acclimatization ◽

Normoxic Control ◽

Near Term ◽

Induced Changes

In response to high-altitude long-term hypoxemia, the cerebral arteries of fetal and adult sheep show decreased contractile responses to norepinephrine (NE) and other agonists. To test the hypothesis that hypoxia-induced developmental and vessel specific cerebral artery contractility changes are mediated, in part, by changes in alpha1-adrenergic receptor (alpha1-AR) density and/or NE-induced inositol 1,4,5-trisphosphate [Ins(1,4,5)P3] responses, we performed the following study. In common carotid (Com) and main branch cerebral (MBC) arteries from normoxic adult ewes and near-term fetuses and those acclimatized to high altitude (3,820 m), we quantified alpha1-AR density (maximal binding in fmol/mg protein) and affinity (dissociation constant in nM) with the alpha1-AR antagonist [3H]prazosin. In addition, we quantified NE-induced Ins(1,4,5)P3 responses in these arteries. With long-term hypoxemia, alpha1-AR density in fetal and adult Com decreased 75% (from 113 +/- 18 to 28 +/- 5 fmol/mg protein) and 66% (from 54 +/- 3 to 18 +/- 4 fmol/mg protein), respectively, from normoxic control values. alpha1-AR density of the fetal and adult MBC decreased 76% (from 47 +/- 4 to 11 +/- 1 fmol/mg protein) and 61% (from 23 +/- 3 to 9 +/- 3 fmol/mg protein), respectively, from controls. In hypoxemic adult Com, the NE-induced Ins(1,4,5)P3 response decreased 51% (from 309 +/- 38 to 151 +/- 24%) from the control value. In fetal and adult MBC, long-term hypoxemia was associated with decreases of 35% (from 345 +/- 40 to 225 +/- 30%) and 44% (from 355 +/- 55 to 199 +/- 16%), respectively, from control values. We conclude that in the adult Com and MBC vessels, acclimatization to high-altitude, long-term hypoxemia was associated with significant decreases in both alpha1-AR density values and Ins(1,4,5)P3 responses to NE. Similarly, in the fetal MBC arteries, high-altitude hypoxemia was associated with marked attenuation of both alpha1-AR density and NE-induced Ins(1,4,5)P3 responses. The magnitude of decreases in NE-induced Ins(1,4,5)P3 responses in these vessels correlated fairly well with the decreases in alpha1-AR density. These findings suggest that changes in noradrenergic receptor-second messenger coupling may play a role in altered cerebrovascular tone in association with high-altitude acclimatization and other forms of long-term hypoxia in both fetus and adult.

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