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Vitamin D decrease during inflammation is probably due to interferons - Oct 2012

Circulating interferon-γ correlates with 1,25(OH)D and the 1,25(OH)D-to-25(OH)D ratio.

Cytokine. 2012 Oct;60(1):23-6. doi: 10.1016/j.cyto.2012.05.015. Epub 2012 Jun 15.
Barker T, Martins TB, Kjeldsberg CR, Trawick RH, Hill HR.
The Orthopedic Specialty Hospital, Murray, UT 84107, USA. tyler.barker at imail.org

The mechanism responsible for the decrease in vitamin D status (i.e., plasma or serum 25-hydroxyvitamin D (25(OH)D) concentration) during inflammatory stress is unknown in humans.

Interferon (IFN)-γ is an inflammatory cytokine that regulates vitamin D metabolism in isolated immune cells, but data suggesting this regulation exists in vivo is lacking. The purpose of this study, therefore, was to associate circulating IFN-γ perturbations with 25(OH)D and 1,25-dihydroxyvitamin D (1,25(OH)D) alterations during inflammatory stress in young adults recovering from anterior cruciate ligament (ACL) reconstruction.

Plasma 25(OH)D, 1,25(OH)D and IFN-γ concentrations were measured in fasting blood draw samples obtained from twelve-male patients pre-surgery and 90-m, 3-d and 7-d post-surgery. 25(OH)D decreased significantly (p<0.05) after surgery, and strikingly, tended to inversely correlate (r=-0.32, p=0.058) with IFN-γ changes from pre- to post- (i.e., 90-m, 3-d, and 7-d) surgery. Additionally, 1,25(OH)D (r=0.37, p<0.05) and the 1,25(OH)D-to-25(OH)D ratio (r=0.52, p<0.05) changes from pre- to post- (i.e., 90-m, 3-d, and 7-d) surgery correlated with those of IFN-γ. These are the first reported in vivo findings suggesting that the 25(OH)D decrease and conversion to 1,25(OH)D increase with increasing IFN-γ in the circulation.

We conclude that IFN-γ contributes to the decrease in vitamin D and the conversion of vitamin D to its active hormonal form in the circulation during inflammatory insult in humans.

Copyright © 2012 Elsevier Ltd. All rights reserved.

PMID: 22704696

Funded by USANA

Vitamin D sufficiency associates with an increase in anti-inflammatory cytokines after intense exercise in humans. - Feb 2014

Cytokine. 2014 Feb;65(2):134-7. doi: 10.1016/j.cyto.2013.12.004. Epub 2013 Dec 31.
Barker T1, Martins TB2, Hill HR3, Kjeldsberg CR3, Dixon BM4, Schneider ED4, Henriksen VT5, Weaver LK6.

The purpose of this study was to identify the influence of vitamin D status (insufficient vs. sufficient) on circulating cytokines and skeletal muscle strength after muscular injury. To induce muscular injury, one randomly selected leg (SSC) performed exercise consisting of repetitive eccentric-concentric contractions. The other leg served as the control. An averaged serum 25(OH)D concentration from two blood samples collected before exercise and on separate occasions was used to establish vitamin D insufficiency (<30ng/mL, n=6) and sufficiency (>30ng/mL, n=7) in young, adult males. Serum cytokine concentrations, single-leg peak isometric force, and single-leg peak power output were measured before and during the days following the exercise protocol. The serum IL-10 and IL-13 responses to muscular injury were significantly (both p<0.05) increased in the vitamin D sufficient group. The immediate and persistent (days) peak isometric force (p<0.05) and peak power output (p<0.05) deficits in the SSC leg after the exercise protocol were not ameliorated with vitamin D sufficiency. We conclude that vitamin D sufficiency increases the anti-inflammatory cytokine response to muscular injury.
PMID: 24388225

See also VitaminDWiki