The Journal of steroid biochemistry and molecular biology
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J. Steroid Biochem. Mol. Biol. · Apr 2015
ReviewVitamin D supplementation and antibacterial immune responses in adolescents and young adults with HIV/AIDS.
Human monocytes activated by toll-like receptor 2/1 ligand (TLR2/1L) show enhanced expression of the vitamin D receptor (VDR) and the vitamin D-activating enzyme 1α-hydroxylase (CYP27B1). The resulting intracrine conversion of precursor 25-hydroxyvitamin D3 (25OHD) to active 1,25-dihydroxyvitamin D (1,25(OH)2D) can stimulate expression of antibacterial cathelicidin (CAMP). To determine whether this response is functional in HIV-infected subjects (HIV+ ), serum from HIV+ subjects pre- and post-vitamin D supplementation was utilized in monocyte cultures with or without TLR2/1L. ⋯ Expression of CAMP increased significantly from baseline after 52 weeks of vitamin D-supplementation. At this time point, TLR2/1L-induced CAMP was positively associated with percent change from baseline in 25OHD (p=0.029 overall and 0.002 within vitamin D-supplemented only). These data indicate that vitamin D supplementation in HIV-infected subjects can promote improved antibacterial immunity, but also suggest that longer periods of supplementation are required to achieve this.
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J. Steroid Biochem. Mol. Biol. · Apr 2015
ReviewEffects of supplemental vitamin D and calcium on normal colon tissue and circulating biomarkers of risk for colorectal neoplasms.
This brief review, based on an invited presentation at the 17th Workshop on Vitamin D, is to summarize a line of the author's research that has been directed at the intertwined missions of clarifying and/or developing vitamin D and calcium as preventive agents against colorectal cancer in humans, understanding the mechanisms by which these agents may reduce risk for the disease, and developing 'treatable' biomarkers of risk for colorectal cancer. The biological plausibility and observational and clinical trial evidence for vitamin D and calcium in reducing risk for colorectal neoplasms, the development of pre-neoplastic biomarkers of risk for colorectal neoplasms, and the clinical trial findings from the author's research group on the efficacy of vitamin D and calcium in modulating these biomarkers are summarized. Regarding the latter, we tested the efficacy of 800 IU (20μg) of vitamin D3 and 2.0g of calcium daily, alone and combined vs. placebo over 6 months on modulating normal colon tissue and circulating hypothesis-based biomarkers of risk for colorectal neoplasms in a randomized, double-blind, placebo-controlled, 2×2 factorial design clinical trial (n=92). ⋯ The findings for calcium were similar to those for vitamin D. These findings indicate that supplemental vitamin D3 or calcium can favorably modulate multiple normal colon tissue and circulating hypothesis-based biomarkers of risk for colorectal neoplasms in sporadic colorectal adenoma patients. This article is part of a Special Issue entitled '17th Vitamin D Workshop'.