Vitamin D supplementation decreases immune activation and exhaustion in HIV-1-infected youth.

BACKGROUND: Heightened immune activation and exhaustion drive HIV disease progression and comorbidities. Vitamin D has pleiotropic immunomodulatory effects, but little is known about the effects of supplementation in HIV. Our study investigates changes in immune activation and exhaustion markers after 12 months of supplementation in virologically suppressed HIV-infected youth with vitamin D insufficiency. METHODS: This is a randomized, active-control, double-blind trial investigating with three different vitamin D3 doses (18,000 [standard/active-control dose], 60,000 [moderate dose] and 120,000 IU/month [high dose]) in 8-25-year-old HIV-infected youth on combination antiretroviral therapy with baseline serum 25-hydroxyvitamin D (25(OH)D) concentrations ≤30 ng/ml. Only subjects (n=51) who maintained an undetectable HIV-1 RNA over the 12-month study period were included in this analysis. RESULTS: Baseline serum 25(OH)D concentrations and immune activation/exhaustion markers were not different between groups. By 12 months, 25(OH)D increased significantly within each dosing group with the greatest increase and most sustained concentrations ≥30 ng/ml in the high-dose group. Overall, all measured markers decreased with CD4 activation (CD4+CD38+HLA-DR+), CD8 activation (CD8+CD38+HLA-DR+), CD4 exhaustion (CD4+CD38+HLA-DR+PD1+) and inflammatory monocytes (CD14+CD16+) reaching statistical significance. When analysed separately, there were no significant decreases in the moderate- or standard-dose groups, but CD4 and CD8 activation and inflammatory monocytes decreased significantly in the high-dose group. CONCLUSIONS: Vitamin D supplementation decreased markers of T-cell activation/exhaustion and monocyte activation in HIV-infected youth, with subjects given the highest dose (120,000 IU/month) showing the greatest decreases. These data suggest that high-dose vitamin D supplementation may attenuate immune activation and exhaustion, and serve as adjuvant therapy to antiretroviral therapy in HIV. ClinicalTrials.gov identifier: NCT01523496.

Effects of Vitamin D Supplementation on Bone Mineral Density and Bone Markers in HIV-Infected Youth.

BACKGROUND: Low bone mineral density (BMD) is a significant comorbidity in HIV. However, studies evaluating vitamin D supplementation on bone health in this population are limited. This study investigates changes in bone health parameters after 12 months of supplementation in HIV-infected youth with vitamin D insufficiency. METHODS: This is a randomized, active-control, double-blind trial investigating changes in bone parameters with 3 different vitamin D3 doses [18,000 (standard/control dose), 60,000 (moderate dose), and 120,000 IU/monthly (high dose)] in HIV-infected youth 8-25 years old with baseline serum 25-hydroxyvitamin D (25(OH)D) concentrations <30 ng/mL. BMD and bone turnover markers were measured at baseline and 12 months. RESULTS: One hundred two subjects enrolled. Over 12 months, serum 25(OH)D concentrations increased with all doses, but the high dose (ie, 120,000 IU/monthly) maintained serum 25(OH)D concentrations in an optimal range (≥30 or ≥20 ng/mL) throughout the study period for more subjects (85% and 93%, respectively) compared with either the moderate (54% and 88%, respectively) or standard dose (63% and 80%, respectively). All dosing groups showed some improvement in BMD; however, only the high-dose arm showed significant decreases in bone turnover markers for both procollagen type 1 aminoterminal propeptide (-3.7 ng/mL; P = 0.001) and Β-CrossLaps (-0.13 ng/mL; P = 0.0005). CONCLUSIONS: High-dose vitamin D supplementation (120,000 IU/mo) given over 12 months decreases bone turnover markers in HIV-infected youth with vitamin D insufficiency, which may represent an early, beneficial effect on bone health. High vitamin D doses are needed to maintain optimal serum 25(OH)D concentrations.

Effects of cholecalciferol supplementation on serum and urinary vitamin D metabolites and binding protein in HIV-infected youth.

Vitamin D insufficiency is widespread in HIV-infected patients. HIV and/or antiretroviral therapy (ART), particularly efavirenz (EFV), may interfere with vitamin D metabolism. However, few data from randomized, controlled trials exist. Here, we investigate changes in vitamin D metabolites and binding protein (VDBP) after 6 months of supplementation in a randomized, active-control, double-blind trial investigating 2 different monthly cholecalciferol (vitamin D3) doses [60,000 (medium) or 120,000 (high) IU/month] vs. a control arm of 18,000 IU/month in 8-25year old HIV-infected youth on ART with HIV-1 RNA <1000 copies/mL and baseline 25-hydroxycholecalciferol (25(OH)D3) ≤30ng/mL. A matched healthy uninfected group was enrolled in a similar parallel study for comparison. Changes after 6 months were analyzed as intent-to-treat within/between groups [control group (low dose) vs. combined supplementation doses (medium+high)]. At 6 months, 55% vs. 82% of subjects in control and supplementation groups, respectively, reached 25(OH)D3 ≥30ng/mL (P=0.01) with no difference between medium and high doses (both 82% ≥30ng/mL). There were few differences for those on EFV vs. no-EFV, except serum VDBP decreased in EFV-treated subjects (both within- and between-groups P≤0.01). There were no significant differences between the HIV-infected vs. healthy uninfected groups. The major finding of the present study is that cholecalciferol supplementation (60,000 or 120,000 IU/month) effectively raises serum 25(OH)D3 in the majority of HIV-infected subjects, regardless of EFV use. Notably, response to supplementation was similar to that of uninfected subjects.

Arterial stiffness in HIV-infected youth and associations with HIV-related variables.

Children and young adults infected with HIV are at elevated risk for cardiovascular disease (CVD). However, scarce data exist on the utility of non-invasive methods to diagnose subclinical CVD, such as pulse wave velocity (PWV), a non-invasive measure of arterial stiffness. The objectives of this study were to assess the relationship of carotid-femoral PWV with subclinical atherosclerosis measured by carotid intima-media thickness (IMT), compare measurements to healthy controls, and evaluate variables associated with PWV in HIV-infected youth. One hundred and one 8-25 year-old subjects on stable antiretroviral therapy with low-level viremia or an undetectable HIV-1 RNA were enrolled, along with 86 healthy controls similar in age, sex and race. There was no significant difference in PWV between groups (median (Q1, Q3): 5.7 (5.2, 6.3) vs 5.7 (4.9, 6.5) m/s; P = 0.81). Among the HIV-infected subjects, PWV was positively correlated with both internal carotid artery (R = 0.31, P = 0.02) and carotid bulb IMT (R = 0.29, P = 0.01). In multivariable regression, only current alcohol consumption and systolic blood pressure were independently associated with PWV in the HIV-infected group (where current alcohol consumption and higher systolic blood pressure were associated with higher PWV); whereas, age, body mass index, and current marijuana use were associated with PWV in healthy controls. In this study of PWV in HIV-infected youth, measures of arterial stiffness were not different between subjects and controls. However, in HIV-infected youth, there was a significant association between PWV and carotid IMT, as well as between PWV and current alcohol consumption. Thus, PWV may have potential as a useful, non-invasive method to assess CVD risk in HIV-infected youth, but further investigation is needed.

Increased Immune Activation and Exhaustion in HIV-infected Youth.

BACKGROUND: Immune activation and exhaustion drive several comorbidities and disease progression in HIV-infected adults; however, they are not well studied in HIV-infected youth. Thus, this study sought to examine levels of immune activation and exhaustion in this population, investigate associated HIV- and non-HIV-related variables and compare results with a matched healthy control group. METHODS: HIV-infected youth 8-25 years of age on stable antiretroviral therapy with an HIV-1 RNA level <1000 copies/mL were enrolled, along with matched healthy controls. We measured T-cell and monocyte immune activation and exhaustion markers in cryopreserved peripheral blood mononuclear cell and plasma samples. RESULTS: A total of 136 subjects (80 HIV+: 66% male; 91% black) were enrolled. Markers of CD4+ and CD8+ T-cell activation were higher in the HIV-infected group versus controls [mean % CD4+CD38+HLA-DR+ and CD8+CD38+HLA-DR+ = 2.2 versus 1.5 (P=0.002) and 4.9 versus 2.2 (P<0.0001), respectively], as were exhausted CD4+ and CD8+ T-cells [mean % CD4+CD38+HLA-DR+PD-1+ and CD8+CD38+HLA-DR+PD-1+ = 1.0 versus 0.5 (P<0.0001) and 1.6 versus 0.7 (P<0.0001), respectively]. There were no differences in proportions of inflammatory or patrolling monocytes between groups (P>0.05); however, soluble CD14 was higher in HIV-infected compared with controls (1.6 versus 1.4 µg/mL; P=0.01). Current CD4 count, low-density lipoprotein cholesterol and age were the variables most associated with CD4+ and CD8+ T-cell activation. CONCLUSIONS: CD4+ and CD8+ T-cell immune activation and exhaustion are higher in HIV-infected youth compared with matched controls, while monocyte subpopulations are not altered despite a high soluble CD14 level. The clinical significance of the increased immune activation and exhaustion should be further explored.