The Effect of Cholecalciferol and Calcitriol on Biochemical Bone Markers in HIV Type 1-Infected Males: Results of a Clinical Trial

Abstract

HIV-1-infected patients have an increased risk of osteoporosis and fractures. The main objective of this study was to evaluate the bone metabolism in HIV-1-infected patients exposed to calcitriol and cholecalciferol. We also investigated the relationship between T cells and bone markers. We conducted a placebo-controlled randomized study running for 16 weeks including 61 HIV-1-infected males, of whom 51 completed the protocol. Nineteen participants were randomized to daily treatment with (A) 0.5–1.0 μg calcitriol and 1,200 IU (30 μg) cholecalciferol, 17 participants to (B) 1,200 IU cholecalciferol, and 15 participants to (C) placebo. At baseline and after 16 weeks, we determined collagen type 1 trimeric cross-linked peptide (CTx), procollagen type 1 N-terminal peptide (P1NP), parathyroid hormone (PTH), ionized calcium, 25-hydroxyvitamin D (25OHD), and 1,25-dihydroxyvitamin D [1,25(OH)₂D]. We determined naive CD4⁺ and CD8⁺, activated CD4⁺ and CD8⁺, and regulatory CD4⁺CD25⁺CD127(low) T lymphocytes. Baseline levels of P1NP and CTx correlated (coefficient 0.5, p<0.001) with each other but not with PTH, 25OHD, or 1,25(OH)₂D. In patients receiving calcitriol and cholecalciferol, the mean levels of P1NP (p<0.001) and CTx (p= 0.002) declined significantly compared to our placebo group. Based on changes in P1NP and CTx, we estimated that net bone formation occurred more frequently in group A compared to groups B and C. PTH correlated inversely with naive CD4⁺ and CD8⁺ cells. Otherwise, no relationships between bone markers and T lymphocytes were demonstrated. Supplementation with calcitriol and cholecalciferol induced biochemical indications of bone formation in HIV-1 patients.