Changes in calciotropic hormones and biochemical markers of bone metabolism in patients with human immunodeficiency virus infection

Induction of Autophagy to Achieve a Human Immunodeficiency Virus Type 1 Cure

Effective antiretroviral therapy has led to significant human immunodeficiency virus type 1 (HIV-1) suppression and improvement in immune function. However, the persistence of integrated proviral DNA in latently infected reservoir cells, which drive viral rebound post-interruption of antiretroviral therapy, remains the major roadblock to a cure. Therefore, the targeted elimination or permanent silencing of this latently infected reservoir is a major focus of HIV-1 research. The most studied approach in the development of a cure is the activation of HIV-1 expression to expose latently infected cells for immune clearance while inducing HIV-1 cytotoxicity—the “kick and kill” approach. However, the complex and highly heterogeneous nature of the latent reservoir, combined with the failure of clinical trials to reduce the reservoir size casts doubt on the feasibility of this approach. This concern that total elimination of HIV-1 from the body may not be possible has led to increased emphasis on a “functional cure” where the virus remains but is unable to reactivate which presents the challenge of permanently silencing transcription of HIV-1 for prolonged drug-free remission—a “block and lock” approach. In this review, we discuss the interaction of HIV-1 and autophagy, and the exploitation of autophagy to kill selectively HIV-1 latently infected cells as part of a cure strategy. The cure strategy proposed has the advantage of significantly decreasing the size of the HIV-1 reservoir that can contribute to a functional cure and when optimised has the potential to eradicate completely HIV-1.

Vitamin D status and associated factors among HIV-infected children and adolescents on antiretroviral therapy in Kampala, Uganda

Background

A high prevalence of suboptimal serum vitamin D has been reported among HIV infected children even in countries with high sunshine abundance throughout the year. Vitamin D is a potent immune modulator of innate and adaptive immune responses. Vitamin D regulates immune responses through the vitamin D receptor on CD4 cells. We aimed to determine the vitamin D status of HIV infected children and factors associated with suboptimal vitamin D.

Methods

This was a cross sectional study. We enrolled children aged between 6 months and 12 years attending an outpatient paediatric HIV clinic. Serum 25-hydroxyvitamin D (25(OH)D) was measured using the electrochemoluminisence method. Suboptimal vitamin D was defined as 25(OH)D <30 ng/ml, vitamin D insufficiency and deficiency were 21–29 ng/ml and <20 ng/ml respectively. Anthropometry, physical exam and medical history were documented. Logistic regression was performed.

Results

We enrolled 376 children with mean age (sd) 8.05 years (3.03), a median (IQR) duration of ART of 5.9 years (3.2–8.4). Majority of the children (64%) had been exposed to non nucleoside reverse transcriptase inhibitors (NNRTIs). A third were severely immunosuppressed (CD4% ≤15%) at ART initiation. At the time of the study, the majority (89%) were virologically suppressed (VL <1000 copies/ml). Prevalence of 25(OH)D <30 ng/ml was 49 (13%) of 375 participants and 11 (3%) had 25(OH)D <20 ng/ml. Lopinavir/ritonavir regimen was independently associated with 25(OH)D <30 ng/ml; OR 0.27 CI (0.13–0.57), p value-0.002. Serum 25(OH)D <20 ng/ml was associated with CD4 count ≤15% at ART initiation OR 6.55(1.30–32.9), p value—0.023 and use of NNRTIs; OR 10.9(1.22–96.2), p value—0.03.

Conclusion

We found a low prevalence of suboptimal vitamin D compared to earlier reports. Severe immunosuppression at ART initiation and use of NNRTIs increases odds of deficiency. Vitamin D supplementation should be considered in severely immunosuppressed children initiating ART.

People with HIV infection had lower bone mineral density and increased fracture risk: a meta-analysis

A meta-analysis to investigate the difference in fracture risk between individuals with and without HIV infection was performed. People living with HIV had lower bone mineral density (BMD) and greater risks of overall fractures and fragility fractures. Reducing fragility and maintaining skeletal strength for PLWH are urgently needed for this population.

PURPOSE

The introduction of effective antiretroviral therapy increased the life expectancy of people living with HIV (PLWH). This population now faces problems related to aging such as decreased bone mineral density (BMD) and increased fracture risk. Some antiretroviral therapies may also negatively impact bone health. We performed a meta-analysis to investigate the difference in the fracture risk between individuals with and without HIV infection.

METHODS

We compared BMD, risk of fragility fracture, and risk of all fracture between the two groups. This study included 35 articles with 106,994 PLWH and 228,794,335 controls.

RESULTS

PLWH had lower lumbar spine and hip BMD than controls. PLWH had a higher prevalence of all fracture events (4.08% versus 0.44%) and fragility fractures (2.66% versus 2.19%). The relative risks of all and fragility fractures of PLWH were 1.91 (95% confidence interval (CI), 1.46-2.49; p < 0.001) and 1.68 (95% CI: 1.40-2.01; p < 0.001). PLWH also had more vertebral fractures (1.26% versus 0.37%; RR, 1.97; 95% CI: 1.22-3.2; p < 0.05), hip fractures (1.38% versus 0.81%; RR, 1.88; 95% CI: 0.99-3.57; p = 0.05), and wrist fractures (1.38% versus 1.29%; RR, 1.67; 95% CI: 1.13-2.45; p < 0.05) than healthy controls. The pooled incidence of fractures was 1.72 per 100 person-years in PLWH and 1.29 in healthy controls.

CONCLUSION

PLWH had lower BMD and greater risks of all fractures and fragility fractures. Reducing fragility and maintaining skeletal strength for PLWH are urgently needed for this population.

Reduced Serum Osteocalcin in High-Risk Alcohol Using People Living With HIV Does Not Correlate With Systemic Oxidative Stress or Inflammation: Data From the New Orleans Alcohol Use in HIV Study

BACKGROUND

HIV infection is now largely a chronic condition as a result of the success of antiretroviral therapy. However, several comorbidities have emerged in people living with HIV (PLWH), including alcohol use disorders and musculoskeletal disorders. Alcohol use has been associated with lower bone mineral density, alterations to circulating bone turnover markers, and hypocalcemia. The pathophysiological basis of bone loss in the PLWH population is unclear but has been suggested to be linked to oxidative stress and inflammation. To test the hypothesis that PLWH consuming excessive alcohol have altered markers of bone turnover and/or calcium homeostasis in association with oxidative stress, we correlated measurements of alcohol consumption with markers of oxidative stress and inflammation, serum calcium concentrations, and measurements of bone turnover, including c-terminal telopeptide cross-links (CTX-1) and osteocalcin.

METHODS

Data were drawn from cross-sectional baseline data from the ongoing New Orleans Alcohol Use in HIV (NOAH) study, comprised of 365 in care PLWH. Alcohol consumption measures (Alcohol Use Disorders Test, 30-day timeline follow-back calendar, and phosphatidylethanol [PEth]) were measured in a subcohort of 40 subjects selected based on highest and lowest PEth measurements. Multivariate linear regression was performed to test the relationships between alcohol consumption and systemic oxidative stress (4-hydroxynonenal; 4-HNE) and inflammation (c-reactive protein; CRP).

RESULTS

Serum calcium and CTX-1 did not differ significantly between the high and low-PEth groups. Individuals in the high-PEth group had significantly lower serum osteocalcin (median low-PEth group: 13.42 ng/ml, inter-quartile range [IQR] 9.26 to 14.99 ng/ml; median high-PEth group 7.39 ng/ml, IQR 5.02 to 11.25 ng/ml; p = 0.0005, Wilcoxon rank-sum test). Osteocalcin negatively correlated with PEth (Spearman r = -0.45, p = 0.05) and self-reported measures after adjusting for covariates. Alcohol consumption showed mild, but significant, positive associations with serum 4-HNE, but not with CRP. Osteocalcin did not correlate with either 4-HNE or CRP.

CONCLUSIONS

In this subcohort of PLWH, we detected significant associations between at-risk alcohol use and osteocalcin, and at-risk alcohol use and serum 4-HNE, suggesting suppression of bone formation independent of increased systemic oxidative stress with increasing alcohol consumption.

Distinct biomarker signatures in HIV acute infection associate with viral dynamics and reservoir size

Estimating the size of the viral reservoir is critical for HIV cure strategies. Biomarkers in peripheral circulation may give insights into the establishment of the viral reservoir in compartments not easily accessible. We therefore measured systemic levels of 84 soluble biomarkers belonging to a broad array of immune pathways in acute HIV infection in both antiretroviral therapy-naive (ART-naive) individuals as well as individuals who began ART upon early detection of HIV infection. These biomarkers were measured longitudinally during acute and chronic infection and their relationship to viral reservoir establishment and persistence was assessed. We observed several distinct biomarker pathways induced following HIV infection such as IFN-γ-signaled chemokines, proinflammatory markers, and TNF-α-family members. Levels of several of these factors directly correlated with contemporaneous viral loads and/or frequency of peripheral blood mononuclear cells harboring HIV DNA during acute HIV infection. MCP-1, MIP-3β, sTNFR-II, and IL-10 levels prior to ART associated with HIV DNA levels after 96 weeks of treatment, suggesting a link between early immune signaling events and the establishment and persistence of the viral reservoir during ART. Furthermore, they offer potentially novel tools for gaining insight into relative reservoir size in acutely infected individuals and the potential of associated risks of treatment interruption.

Vitamin D Deficiency in HIV Infection: Not Only a Bone Disorder

Hypovitaminosis D is a worldwide disorder, with a high prevalence in the general population of both Western and developing countries. In HIV patients, several studies have linked vitamin D status with bone disease, neurocognitive impairment, depression, cardiovascular disease, high blood pressure, metabolic syndrome, type 2 diabetes mellitus, infections, autoimmune diseases like type 1 diabetes mellitus, and cancer. In this review, we focus on the most recent epidemiological and experimental data dealing with the relationship between vitamin D deficiency and HIV infection. We analysed the extent of the problem, pathogenic mechanisms, clinical implications, and potential benefits of vitamin D supplementation in HIV-infected subjects.

Vitamin D₃supplementation in Batswana children and adults with HIV: a pilot double blind randomized controlled trial

Objectives

Since vitamin D insufficiency is common worldwide in people with HIV, we explored safety and efficacy of high dose cholecalciferol (D₃) in Botswana, and evaluated potential modifiers of serum 25 hydroxy vitamin D change (Δ25D).

Design

Prospective randomized double-blind 12-week pilot trial of subjects ages 5.0–50.9 years.

Methods

Sixty subjects randomized within five age groups to either 4000 or 7000IU per day of D₃ and evaluated for vitamin D, parathyroid hormone, HIV, safety and growth status. Efficacy was defined as serum 25 hydroxy vitamin D (25D) ≥32ng/mL, and safety as no simultaneous elevation of serum calcium and 25D. Also assessed were HIV plasma viral RNA viral load (VL), CD4%, anti-retroviral therapy (ART) regime, and height-adjusted (HAZ), weight-adjusted (WAZ) and Body Mass Index (BMIZ) Z scores.

Results

Subjects were 50% male, age (mean±SD) 19.5±11.8 years, CD4% 31.8±10.4, with baseline VL log₁₀ range of <1.4 to 3.8 and VL detectable (>1.4) in 22%. From baseline to 12 weeks, 25D increased from 36±9ng/ml to 56±18ng/ml (p<0.0001) and 68% and 90% had 25D ≥32ng/ml, respectively (p = 0.02). Δ25D was similar by dose. No subjects had simultaneously increased serum calcium and 25D. WAZ and BMIZ improved by 12 weeks (p<0.04). HAZ and CD4% increased and VL decreased in the 7000IU/d group (p<0.04). Younger (5–13y) and older (30–50y) subjects had greater Δ25D than those 14–29y (26±17 and 28±12 vs. 11±11ng/ml, respectively, p≤0.001). Δ25D was higher with efavirenz or nevirapine compared to protease inhibitor based treatment (22±12, 27±17, vs. 13±10, respectively, p≤0.03).

Conclusions

In a pilot study in Botswana, 12-week high dose D₃ supplementation was safe and improved vitamin D, growth and HIV status; age and ART regimen were significant effect modifiers.

Trial Registration

ClinicalTrials.gov NCT02189902

Vitamin D deficiency and altered bone mineral metabolism in HIV-infected individuals

Although patients with HIV infection are living decades longer than before with the advent of combination antiretroviral therapy, they have an increased rate of co-morbidities associated with chronic HIV, such as osteoporosis, cardiovascular disease, and immune dysfunction. Many of these complications are known to be affected by vitamin D status in the general population. Thus, the high rate of vitamin D deficiency among HIV-infected patients is alarming. Many observational and cohort studies have demonstrated that vitamin D deficiency is associated with these HIV-related complications, but randomized, placebo-controlled trials are limited. This paper reviews recent data on vitamin D deficiency in HIV infection.

Alendronate Reduces Bone Resorption in HIV-Associated Osteopenia/Osteoporosis

PURPOSE

To evaluate the effects of alendronate, vitamin D, and calcium supplementation on bone metabolism and bone mineral density (BMD) in both HIV-infected men and women treated with highly active antiretroviral therapy (HAART).

METHOD

We performed a 52-week prospective, multicenter, randomized, open-label clinical trial. Eligible participants were on stable HAART and had BMD values at the femoral neck or lumbar spine that corresponded to a t score less than -1. Patients were randomized to receive alendronate 70 mg weekly or no alendronate; calcium 1000 mg daily and vitamin D 500 IU daily were provided to all study recipients. Primary endpoint of the study was the change in bone metabolism evaluated by N-telopeptide of type 1 collagen and bone-specific alkaline phosphatase; the secondary endpoint was BMD variation.

RESULTS

18 patients were randomized to the alendronate and 23 to the no-alendronate group (controls). The alendronate-treatment group compared to controls had a significant decrease in serum N-telopeptides, 1914 +/- 1433.4 vs. 3967 +/- 1650.5 pM/L (p = .005) after 1 year. Lumbar spine BMD increased by 4% in the alendronate group (p = .004) vs. 3.7% (p = .062) in controls, compared to baseline values. Femoral neck BMD decreased by 0.5% in the alendronate group (p = .05) and by 3.5% in the control group (p = .04). No between-groups differences for BMD were found (Delta lumbar-BMD 0.0351 +/- 0.0406 in cases and 0.0356 +/- 0.073 in controls [p = .977], Delta femoral-BMD -0.085 +/- 0.160 in cases and -0.100 +/- 0.165 in controls [p = .795]).

CONCLUSION

Alendronate plus vitamin D and calcium was effective in reducing bone resorption. Alendronate improved lumbar BMD and minimized femoral BMD decrease after 52 weeks compared to treatment with vitamin D and calcium alone in patients on HAART with osteopenia/osteoporosis.

High-dose vitamin D3 supplementation in children and young adults with HIV: a randomized, placebo-controlled trial

BACKGROUND

Suboptimal vitamin D status is prevalent in HIV-infected patients and associated with increased risk of disease severity and morbidity. We aimed to determine 12-month safety and efficacy of daily 7000 IU vitamin D3 (vitD3) versus placebo to sustain increased serum 25-hydroxyvitamin D (25(OH)D) and improve immune status in HIV-infected subjects.

METHODS

This was a double-blind trial of perinatally acquired HIV (PHIV)-infected subjects or behaviorally acquired HIV (BHIV)-infected subjects (5.0-24.9 years). Safety, 25(OH)D-related parameters and immune status were assessed at baseline, 3, 6 and 12 months.

RESULTS

Fifty-eight subjects enrolled (67% male, 85% African American and 64% BHIV) and 50 completed with no safety concerns. In unadjusted analyses, there were no differences between randomization groups at baseline; at 3, 6 and 12 months, 25(OH)D was higher with supplementation than baseline and higher than with placebo (P < 0.05). In adjusted mixed models, in the supplementation group, the fixed effect of 25(OH)D was higher (P < 0.001). Percentage of naive T-helper cells (Th naive%) were significantly (P < 0.01) and T-helper cells (CD4%) marginally (P < 0.10) increased with supplementation in those taking highly active antiretroviral therapy (HAART), and RNA viral load was reduced (P ≤ 0.05). In exploratory linear models, change in 25(OH)D predicted RNA viral load at 3 and 12 months and CD4% at 3 months (P < 0.05).

CONCLUSIONS

Daily 7000 IU vitD3 for 12 months was safe in HIV-infected subjects and effective in increasing 25(OH)D. Supplementation improved some clinically important HIV immune markers in subjects on HAART. Adjunct therapy with high-dose, daily vitD3 for HIV-infected subjects and for those on/off HAART requires further investigation.

Skeletal health in adults with HIV infection

Concern has been raised that HIV infection, its treatment, or both adversely affect skeletal health. Cross-sectional studies show that bone mineral density (BMD) is 3-5% lower in patients infected with HIV than in uninfected controls, but patients with HIV infection are, on average, 5 kg lighter than uninfected people. After this weight difference is accounted for, BMD differences are smaller and not clinically relevant. Longitudinal studies show short-term BMD loss of 2-4% over 1-2 years when antiretroviral therapy is started, followed by longer periods of BMD increase or stability. Losses are greatest with treatment regimens that contain tenofovir. Patients infected with HIV have slightly higher fracture rates than controls, but the increased risk of fracture is substantially attenuated by adjustment for traditional risk factors for fracture. These reassuring findings suggest that management of skeletal health in HIV should follow guidelines for the general population. In general, effective antiretroviral treatment and avoidance of undernutrition are the two most important factors for maintenance of skeletal health in patients infected with HIV.

Vitamin D and calcium abnormalities in the HIV-infected population

The prevalence of vitamin D deficiency among HIV-infected persons is substantial and comparable to the general population. The factors associated with vitamin D deficiency are similar for both populations but additional factors (ie, use of certain antiretroviral agents) also contribute to vitamin D deficiency among HIV-infected persons. The adverse outcomes associated with vitamin D deficiency considerably overlap with non-AIDS defining illnesses (NADIs) that are increasingly becoming widespread in the aging HIV-infected population. However, there is scant evidence to support any causal inference. Further studies are warranted as efforts to identify and address modifiable risk factors contributing to NADIs continue.

LL-37 concentrations and the relationship to vitamin D, immune status, and inflammation in HIV-infected children and young adults

Antimicrobial peptide LL-37 is produced in response to active vitamin D to exert immunomodulatory effects and inhibits HIV replication in vitro. To date, no studies have investigated LL-37 in HIV-infected patients. This study sought to investigate LL-37 and the relationship to 25-hydroxyvitamin D [25(OH)D] and HIV-related variables in this population. HIV-infected subjects and healthy controls ages 1-25 years old were prospectively enrolled in this cross-sectional study. Fasting plasma LL-37 and 25(OH)D concentrations were measured in duplicate with ELISA. HIV(+) subjects (36 antiretroviral therapy (ART)-experienced subjects; 27 ART-naïve subjects) and 31 healthy controls were enrolled. Overall, 93% were black and the median age was 20 years. There was no difference in median (interquartile range) LL-37 between the HIV-infected group and controls [58.3 (46.4,69.5) vs. 51.3 (40.8,98.2) ng/ml, respectively; p=0.57]; however, the ART-experienced group had higher concentrations than the ART-naive group [66.2 (55.4,77.0) vs. 48.9 (38.9,57.9) ng/ml, respectively; p<0.001]. LL-37 was positively correlated with 25(OH)D in controls, but not in HIV-infected groups, and was positively correlated with current CD4 and ΔCD4 (current-nadir) in the ART-experienced group. After adjustment for age, race, sex, and HIV duration, the association between LL-37 and CD4 remained significant. These findings suggest that HIV and/or HIV-related variables may alter the expected positive relationship between vitamin D and LL-37 and should be further investigated.

Effect of age on the CD4⁺ T-cell impairment in HIV-infected persons without and with cART

BACKGROUND

Knowledge about HIV infection in older persons is becoming increasingly important. CD4⁺ T cells are essential for protective immunity, but little is known about the effect of age on the CD4⁺ T-cell impairment in HIV infection.

METHODS

Treatment-naive patients aged older than 50 or younger than 40 years were studied for absolute and relative frequencies of CD31⁺ naive and CD31⁻ naive CD4⁺ T cells, central memory, effector memory, and terminally differentiated CD4⁺ T cells, and compared with age-matched controls. In addition, cellular proliferation and cytokine secretion properties were determined. CD4⁺ T-cell reconstitution was analyzed in older and younger patients with <350 or ≥ 350 CD4⁺ T cells per microliter at initiation of combination antiretroviral therapy (cART).

RESULTS

CD4⁺ T cells of older but not younger HIV-infected patients showed age-inappropriate low levels of CD31⁻ naive cells, increased levels of effector memory cells, and enhanced interferonγ and interleukin-17 secretion. Impaired CD4⁺ T-cell composition persisted in patients who initiated cART at <350 CD4⁺ T cells per microliter. In patients with CD4⁺ T cells ≥ 350 per microliter, alterations were less pronounced and were reversible with cART. Compared with age-matched controls, total CD4⁺ T-cell counts did not differ between treated younger and older HIV-infected patients.

CONCLUSIONS

These data demonstrate that aging enhances the CD4⁺ T-cell impairment in HIV-infected persons mainly by a loss of CD31⁻ naive cells, accumulation of effector memory cells, and increased pro-inflammatory effector functions. Age-related changes in CD4⁺ T-cell composition can be prevented by an early initiation of cART.

Osteoporosis in Human Immunodeficiency Virus Patients - An Emerging Clinical Concern

The advent of highly active anti-retroviral therapy (HAART) has significantly improved the survival of human immunodeficiency virus (HIV)-infected patients transforming the HIV infection from a fatal illness into a manageable chronic disease. As the number of older HIV-infected individuals increases, several ageing-related co-morbidities including osteopenia/osteoporosis and fractures have emerged. Patients exposed to HIV infection and its treatment may develop fragility fractures with potential significant impact on quality of life and survival. However, the awareness of HIV-related skeletal fragility is still relatively low and most HIV-infected patients are not investigated for osteoporosis and treated with anti-osteoporotic drugs in daily clinical practice. This article reviews the literature data on osteoporosis and osteopenia in HIV infection, focusing on the pathophysiological, clinical and therapeutic aspects of fragility fractures.

The effect of cholecalciferol and calcitriol on biochemical bone markers in HIV type 1-infected males: results of a clinical trial

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.

Correlation of increases in 1,25-dihydroxyvitamin D during vitamin D therapy with activation of CD4+ T lymphocytes in HIV-1-infected males

BACKGROUND

In HIV-1-infected individuals, levels of CD4+ T lymphocytes are depleted and regulatory T-lymphocytes (Tregs) are elevated. In vitro studies have demonstrated effects of vitamin D on the growth and differentiation of these cells. We speculated whether supplementation with vitamin D could have an effect on CD4+ T lymphocytes or Tregs in HIV-1-infected males.

METHODS

We conducted a placebo-controlled randomized study that ran for 16 weeks and included 61 HIV-1-infected males, of whom 51 completed the protocol. The participants were randomized to 1 of 3 daily treatments: (1) 0.5-1.0 µg calcitriol and 1200 IU (30 µg) cholecalciferol, (2) 1200 IU cholecalciferol, (3) placebo. Percentages of the following T-lymphocyte subsets were determined: naïve CD4+ and CD8+ cells, activated CD4+ and CD8+ cells, and CD3+CD4+CD25+CD127low Tregs. Furthermore 1,25-dihydroxyvitamin D, 25-hydroxyvitamin D, and parathyroid hormone were measured.

RESULTS

No significant changes of the studied T-lymphocyte subsets occurred in the treatment groups compared to the placebo group. Increases in 1,25-dihydroxyvitamin D were associated with increases in activated CD4+ T lymphocytes (P = .001) and Tregs (P = .01) in adjusted models. Changes in parathyroid hormone correlated inversely with Tregs (P = .02). Smokers had higher levels of naïve CD4+ T lymphocytes (37% vs 25%;P = .01), naïve CD8+ T lymphocytes (28% vs 19%; P = .03), and Tregs (9% vs 7%; P = .03).

CONCLUSION

Cholecalciferol and calcitriol administered during 16 weeks did not change the levels of T-lymphocyte fractions compared to placebo. However, increases in 1,25-dihydroxyvitamin D were associated with an expansion of activated CD4+ cells and Tregs.

Vitamin D inhibits human immunodeficiency virus type 1 and Mycobacterium tuberculosis infection in macrophages through the induction of autophagy

Low vitamin D levels in human immunodeficiency virus type-1 (HIV) infected persons are associated with more rapid disease progression and increased risk for Mycobacterium tuberculosis infection. We have previously shown that 1α,25-dihydroxycholecalciferol (1,25D3), the active form of vitamin D, inhibits HIV replication in human macrophages through the induction of autophagy. In this study, we report that physiological concentrations of 1,25D3 induce the production of the human cathelicidin microbial peptide (CAMP) and autophagic flux in HIV and M. tuberculosis co-infected human macrophages which inhibits mycobacterial growth and the replication of HIV. Using RNA interference for Beclin-1 and the autophagy-related 5 homologue, combined with the chemical inhibitors of autophagic flux, bafilomycin A₁, an inhibitor of autophagosome-lysosome fusion and subsequent acidification, and SID 26681509 an inhibitor of the lysosome hydrolase cathepsin L, we show that the 1,25D3-mediated inhibition of HIV replication and mycobacterial growth during single infection or dual infection is dependent not only upon the induction of autophagy, but also through phagosomal maturation. Moreover, through the use of RNA interference for CAMP, we demonstrate that cathelicidin is essential for the 1,25D3 induced autophagic flux and inhibition of HIV replication and mycobacterial growth. The present findings provide a biological explanation for the benefits and importance of vitamin D sufficiency in HIV and M. tuberculosis-infected persons, and provide new insights into novel approaches to prevent and treat HIV infection and related opportunistic infections.

Macroautophagy (autophagy - ‘self-eating’, lysosome-dependent degradation and recycling of the intracellular components in response to stress) is an important host defense mechanism against viral and mycobacterial infections. Recent studies have described that activation of autophagy in macrophages reduces the viability of Mycobacterium tuberculosis and HIV due to an intimate autophagy-phagocytosis interaction. Low serum levels of the 25-hydroxycholecalciferol form of vitamin D have been associated with an increased risk for active tuberculosis and HIV disease progression as well as M. tuberculosis susceptibility. In this study, we report that the active form of vitamin D, 1α,25-dihydroxycholecalciferol inhibits the replication of HIV and M. tuberculosis in a concentration dependent manner. Moreover, by inhibiting key stages in the autophagy pathway, we demonstrate that the inhibition of HIV and mycobacterial growth during single infection or dual infection is dependent not only upon the induction of autophagy, but also through phagosomal maturation. Furthermore, through the use of RNA interference for the human cathelicidin microbial peptide we demonstrate that cathelicidin is essential for the 1α,25-dihydroxycholecalciferol induced autophagic flux and inhibition of HIV replication and mycobacterial growth. These findings suggest that the induction of autophagy has the potential to be useful in the treatment of persons co-infected with HIV and M. tuberculosis.

Hormonally active vitamin D3 (1alpha,25-dihydroxycholecalciferol) triggers autophagy in human macrophages that inhibits HIV-1 infection

Autophagy is a self-digestion pathway essential for maintaining cellular homeostasis and cell survival and for degrading intracellular pathogens. Human immunodeficiency virus-1 (HIV-1) may utilize autophagy for replication as the autophagy-related protein-7 (ATG-7), microtubule-associated protein 1 light chain 3, ATG-12, and ATG-16L2 are required for productive HIV-1 infection; however, the effects of autophagy induction on HIV-1 infection are unknown. HIV-1-infected individuals have lower levels of 1α,25-dihydroxycholecalciferol, the hormonally active form of vitamin D, than uninfected individuals. with the lowest concentrations found in persons with AIDS. Using human macrophages and RNA interference for ATG-5 and Beclin-1 and chemical inhibition of phosphatidylinositol 3-kinase, we have found that physiologically relevant concentrations of 1α,25-dihydroxycholecalciferol induce autophagy in human macrophages through a phosphatidylinositol 3-kinase-, ATG-5-, and Beclin-1-dependent mechanism that significantly inhibits HIV-1 replication in a dose-dependent manner. We also show that the inhibition of basal autophagy inhibits HIV-1 replication. Furthermore, although 1α,25-dihydroxycholecalciferol induces the secretion of human cathelicidin, at the concentrations produced in vitro, cathelicidin does not trigger autophagy. Our findings support an important role for autophagy during HIV-1 infection and provide new insights into novel approaches to prevent and treat HIV-1 infection and related opportunistic infections.

Vitamin D deficiency in HIV-infected postmenopausal Hispanic and African-American women

We evaluated vitamin D status in HIV+ and HIV- postmenopausal African-American (AA) and Hispanic women. Most women (74-78%) had insufficient 25-hydroxyvitamin D (25OHD) levels, regardless of HIV status. 25OHD was lower in AA women and women lacking supplement use, providing support for screening and supplementation. Among HIV+ women, 25OHD was associated with current CD4 but not type of antiretroviral therapy.

INTRODUCTION

To evaluate vitamin D status and factors associated with vitamin D deficiency and insufficiency in HIV-infected (HIV+) postmenopausal minority women.

METHODS

In this cross-sectional study, 89 HIV+ and 95 HIV- postmenopausal women (33% AA and 67% Hispanic) underwent assessment of 25OHD, 1,25-dihydroxyvitamin D, parathyroid hormone, markers of bone turnover and bone mineral density by dual energy X-ray absorptiometry.

RESULTS

The prevalence of low 25OHD did not differ by HIV status; the majority of both HIV+ and HIV- women (74-78%) had insufficient levels (<30 ng/ml). Regardless of HIV status, 25OHD was significantly lower in AA subjects, and higher in subjects who used both calcium and multivitamins. In HIV+ women on antiretroviral therapy (ART), 25OHD was directly associated with current CD4 count (r=0.32; p<0.01) independent of age, ethnicity, BMI, or history of AIDS-defining illness. No association was observed between 1,25(OH)(2)D and CD4 count or between serum 25OHD, 1,25(OH)(2)D or PTH and type of ART.

CONCLUSIONS

In postmenopausal minority women, vitamin D deficiency was highly prevalent and associated with AA race and lack of supplement use, as well as lower current CD4 cell count. These results provide support for screening and repletion of vitamin D in HIV+ patients.

Early immune senescence in HIV disease

Non-AIDS-defining co-morbidities that occur despite viral suppression and immune reconstitution using antiretroviral therapy depict early aging process in HIV-infected individuals. During aging, a reduction in T-cell renewal, together with a progressive enrichment of terminally differentiated T cells, translates into a general decline of the immune system, gradually leading to immunosenescence. Inflammation is a hallmark of age-associated comorbidities, and immune activation is a hallmark of HIV disease. Constant stimulation of the immune system by HIV or due to co-infections activates the innate and adaptive immune system, resulting in release of mediators of inflammation. Immune activation coupled with lack of anti-inflammatory responses likely results in accelerated aging in HIV disease. Dysfunctional thymic output, along with HIV-mediated disruption of the gastrointestinal barrier leading to microbial translocation, contributes to the circulating antigenic load driving early senescence in HIV disease.

Deficiency of 25-hydroxyvitamin D in male HIV-positive patients: a descriptive cross-sectional study

The aim of this descriptive cross-sectional study was to describe the prevalence of hypovitaminosis D in a cohort of HIV-seropositive males. Blood samples were collected in November and December 2004 and analyzed in the hospital laboratory. The concentration of 25-hydroxyvitamin D (25(OH)D) was defined as excellent when >75 nmol/l, normal when >50 nmol/l, insufficient when <50 nmol/l, deficient when <25 nmol/l and severely deficient when <12.5 nmol/l. Patient information was extracted from the medical records. A total of 115 males, median age 44 y (range 19-63 y), were included in the study. The median 25(OH)D concentration was 43.0 nmol/l (range 8-163 nmol/l) and the 25(OH)D level was excellent in 13%, normal in 27%, insufficient in 36%, deficient in 20%, and severely deficient in 4% of the cases. Vitamin D level was not associated with age, y with HIV infection, highly active antiretroviral therapy (HAART) or CD4 count. Compared to patients not in treatment, patients on HAART (n = 71) had higher levels of total alkaline phosphatase (median 83.0 vs 75.5 U/l; p = 0.031) and lower, though not significantly, total body mineral density (1.055 vs 1.107 g/cm(2); p = 0.077). This study confirms that the prevalence of hypovitaminosis is high among HIV-infected patients.

First line zidovudine/lamivudine/lopinavir/ritonavir leads to greater bone loss compared to nevirapine/lopinavir/ritonavir

OBJECTIVE

We studied changes in bone mineral density (BMD) and bone turnover after initiation of combination antiretroviral therapy (cART) and the contribution of zidovudine/lamivudine (ZDV/3TC) in particular.

DESIGN

Randomized clinical trial comparing lopinavir/ritonavir(LPV/r) + ZDV/3TC with LPV/r + nevirapine (NVP) in 50 cART-naive men.

METHODS

Dual energy X-ray absorptiometry (DXA) and quantitative computed tomography scans (QCT) were performed at baseline and 3, 12, and 24 months after cART initiation. Serum 25-hydroxy-vitamin D3, parathyroid hormone (PTH), osteocalcin, and urine deoxypyridinoline (DPD)/creatinine ratio were measured.

RESULTS

BMD decreased rapidly in both femoral neck and lumbar spine after cART initiation. BMD loss during 24 months measured by DXA, but not by QCT, was greater in the ZDV/3TC/LPV/r group compared to the NVP/LPV/r group [femoral neck: -6.3% +/- 1.0% (P < 0.0001) compared to -2.3% +/- 0.9% (P = 0.01), between-group P = 0.0006); lumbar spine: -5.1% +/- 0.8% (P < 0.0001) compared to -2.6% +/- 0.7% (P = 0.0006), between-group P = 0.07]. Osteocalcin [+1.60 +/- 0.32 (P < 0.0001) and +1.81 +/- 0.29 (P < 0.0001) nmol/l] and the urine DPD/creatinine ratio [+1.35 +/- 0.44 (P = 0.0029) and +1.19 +/- 0.38 nmol/mmol (P = 0.0024)] increased in both groups over 24 months, with no significant difference between groups. PTH increased to a greater degree in the NVP/LPV/r group [+2.0 +/- 0.31 pmol/l (P < 0.0001)] compared to [+0.81 +/- 0.33 pmol/l (P = 0.021) in the ZDV/3TC/LPV/r group].

CONCLUSION

BMD in both femoral neck and lumbar spine decreased rapidly after initiation of cART, in parallel to an increase in bone turnover. The greater bone loss in the ZDV/3TC/LPV/r group compared to the NVP/LPV/r group suggests that ZDV/3TC contributes to this process. The PTH increase does not explain this greater bone loss.

Is PPARγ a prospective player in HIV-1-associated bone disease?

Currently infection with the human immunodeficiency virus-1 (HIV-1) is in most instances a chronic disease that can be controlled by effective antiretroviral therapy (ART). However, chronic use of ART has been associated with a number of toxicities; including significant reductions in bone mineral density (BMD) and disorders of the fat metabolism. The peroxisome proliferator-activated receptor γ (PPARγ) transcription factor is vital for the development and maintenance of mature and developing adipocytes. Alterations in PPARγ expression have been implicated as a factor in the mechanism of HIV-1-associated lipodystrophy. Both reduced BMD and lipodystrophy have been well described as complications of HIV-1 infection and treatment, and a question remains as to their interdependence. Interestingly, both adipocytes and osteoblasts are derived from a common precursor cell type; the mesenchymal stem cell. The possibility that dysregulation of PPARγ (and the subsequent effect on both osteoblastogenesis and adipogenesis) is a contributory factor in the lipid- and bone-abnormalities observed in HIV-1 infection and treatment has also been investigated. This review deals with the hypothesis that dysregulation of PPARγ may underpin the bone abnormalities associated with HIV-1 infection, and treats the current knowledge and prospective developments, in our understanding of PPARγ involvement in HIV-1-associated bone disease.

Bone mineral density in human immunodeficiency virus-1 infected men with hypogonadism prior to highly-active-antiretroviral-therapy (HAART)

Alterations of bone metabolism have been observed in numerous studies of HIV-infected patients. Sex steroids are known to profoundly influence bone mass and bone turnover. Hypogonadism is common in HIV-infection. Therefore, we performed a cross sectional study of 80 male HIV-infected patients without wasting syndrome, and 20 healthy male controls, in whom we analyzed urine and serum samples for both calciotropic hormones and markers of bone metabolism and of endocrine testicular function. Bone mineral density (BMD) was assessed by dual-energy X-ray absorptiometry both in the lumbar spine and Ward's triangle of the left hip. None of the patients received highly-active-antiretroviral-therapy (HAART). Compared to eugonadal HIV-infected patients, subjects with hypogonadism (n = 32; 40%) showed statistically significant decrease of serum osteocalcin (p < 0.05) and elevated urinary excretion of crosslinks (p < 0.05). However, we found 13 and 15, respectively, patients with osteopenia (t-score -1.0 to -2.5 SD below normal) of the lumbar spine. The dissociation between bone formation and resorption and the reduction of of BMD (p < 0.05) is stronger expressed in patients with hypogonadism. Habitual hypogonadism appears to be of additional relevance for bone metabolism of male HIV-positive patients prior to HAART.

Vitamin D deficiency among HIV type 1-infected individuals in the Netherlands: effects of antiretroviral therapy

Vitamin D regulates bone metabolism but has also immunoregulatory properties. In HIV-infected patients bone disorders are increasingly observed. Furthermore, low 1,25(OH)(2)D(3) levels have been associated with low CD4(+) counts, immunological hyperactivity, and AIDS progression rates. Few studies have examined the vitamin D status in HIV-infected patients. This study will specifically focus on the effects of antiretroviral agents on vitamin D status. Furthermore, the effect of vitamin D status on CD4 cell recovery after initiation of HAART will be evaluated. Among 252 included patients the prevalence of vitamin D deficiency (<35 nmol/liter from April to September and <25 nmol/liter from October to March) was 29%. Female sex, younger age, dark skin, and NNRTI treatment were significant risk factors in univariate analysis, although in multivariate analyses skin pigmentation remained the only independent risk factor. Median 25(OH)D(3) levels were significantly lower in white NNRTI-treated patients [54.5(27.9-73.8) nmol/liter] compared to white PI-treated patients [77.3 (46.6-100.0) nmol/liter, p = 0.007], while among nonwhites no difference was observed. Both PI- and NNRTI-treated patients had significantly higher blood PTH levels than patients without treatment. Moreover, NNRTI treatment puts patients at risk of elevated PTH levels (>6.5 pmol/liter). Linear regression analysis showed that vitamin D status did not affect CD4 cell recovery after initiation of HAART. In conclusion, 29% of the HIV-1-infected patients had vitamin D deficiency, with skin color as an independent risk factor. NNRTI treatment may add more risk for vitamin D deficiency. Both PI- and NNRTI-treated patients showed higher PTH levels and might therefore be at risk of bone problems. Evaluation of 25(OH)D(3) and PTH levels, especially in NNRTI-treated and dark skinned HIV-1-infected patients, is necessary to detect and treat vitamin D deficiency early.

Fracture healing in HIV-positive populations

Highly active anti-retroviral therapy has transformed HIV into a chronic disease with a long-term asymptomatic phase. As a result, emphasis is shifting to other effects of the virus, aside from immunosuppression and mortality. We have reviewed the current evidence for an association between HIV infection and poor fracture healing.

The increased prevalence of osteoporosis and fragility fractures in HIV patients is well recognised. The suggestion that this may be purely as a result of highly active anti-retroviral therapy has been largely rejected. Apart from directly impeding cellular function in bone remodelling, HIV infection is known to cause derangement in the levels of those cytokines involved in fracture healing (particularly tumour necrosis factor-α) and appears to impair the blood supply of bone.

Many other factors complicate this issue, including a reduced body mass index, suboptimal nutrition, the effects of anti-retroviral drugs and the avoidance of operative intervention because of high rates of wound infection. However, there are sound molecular and biochemical hypotheses for a direct relationship between HIV infection and impaired fracture healing, and the rewards for further knowledge in this area are extensive in terms of optimised fracture management, reduced patient morbidity and educated resource allocation. Further investigation in this area is overdue.

Immune activation and inflammation in HIV-1 infection: causes and consequences

Thorough research on HIV is progressively enabling us to understand the intricate mechanisms that link HIV-1 infection to the onset of immunodeficiency. The infection and depletion of CD4(+) T cells represent the most fundamental events in HIV-1 infection. However, in recent years, the role played by chronic immune activation and inflammation in HIV pathogenesis has become increasingly apparent: quite paradoxically, immune activation levels are directly associated with HIV-1 disease progression. In addition, HIV-1-infected patients present intriguing similarities with individuals of old age: their immune systems are characterized by a loss of regenerative capacity and an accumulation of ageing T cells. In this review, we discuss the potential reasons for the establishment of sustained immune activation and inflammation from the early stages of HIV-1 infection, as well as the long-term consequences of this process on the host immune system and health. A simplified model of HIV pathogenesis is proposed, which links together the three major facets of HIV-1 infection: the massive depletion of CD4(+) T cells, the paradoxical immune activation and the exhaustion of regenerative capacity.

Low bone-mineral density in patients with HIV: pathogenesis and clinical significance

PURPOSE OF REVIEW: Low bone-mineral density is a recently recognized metabolic complication of HIV infection and its treatment. While the clinical impact of low bone-mineral density remains uncertain, the prolongation of survival attributable to more effective antiretroviral therapy has contributed to an aging population of HIV-infected patients who may be prone to developing fragility fractures. RECENT FINDINGS: While most of the available data are on young men, recent publications have increased our understanding of the epidemiology of low bone-mineral density and bone loss in HIV-positive women. Most studies suggest that initiation of certain combinations of antiretroviral agents may be associated with moderate bone loss initially, but bone-mineral density usually stabilizes or improves with longer follow-up. Most studies suggest that, despite lower bone-mineral density, fragility fractures are relatively uncommon in HIV-positive patients, perhaps because of their relative youth. SUMMARY: The pathogenesis of low bone-mineral density in HIV-positive patients is complex and multifactorial, and its clinical impact remains unclear. Further research is needed to clarify the approach to optimal screening and treatment of osteoporosis in the setting of HIV infection.

Longitudinal analysis of bone density in human immunodeficiency virus-infected women

OBJECTIVES

The objective of the study was to investigate change in bone mineral density (BMD) over time in HIV-infected women in comparison with healthy control subjects similar in age, race, and body mass index (BMI).

DESIGN

This was a prospective cohort study.

METHODS

BMD was measured by dual-energy x-ray absorptiometry in 100 HIV-infected females and 100 healthy controls similar in age (41 +/- 1 vs. 41 +/- 1 yr, P = 0.57), BMI (26.1 +/- 0.5 vs. 27.2 +/- 0.4 kg/m(2), P = 0.12), and race (60 vs. 65% non-Caucasian, P = 0.47, HIV-infected vs. controls). Changes in BMD were determined every 6 months over 24 months.

RESULTS

At baseline, HIV-infected subjects had lower BMD at the lumbar spine (1.01 +/- 0.01 vs. 1.07 +/- 0.01 g/cm(2), P = 0.001), hip (0.94 +/- 0.01 vs. 0.98 +/- 0.01 g/cm(2), P = 0.02), and femoral neck (0.83 +/- 0.01 vs. 0.87 +/- 0.01 g/cm(2), P = 0.02). Historical low weight, duration of nucleoside reverse transcriptase inhibitor use, and FSH were significantly associated with lumbar BMD, whereas duration of HIV, BMI, historical low weight, smoking pack-years, N-telopeptide of type 1 collagen, viral load, 25 hydroxyvitamin D, and osteocalcin were associated with hip BMD at baseline. In mixed model longitudinal analyses, BMD remained lower in HIV-infected subjects than in controls over 24 months of follow-up (P = 0.001 for the spine, P = 0.04 for the hip, and P = 0.02 for the femoral neck). These differences remained significant controlling for age, race, BMI, and menstrual function. In contrast, rates of change for the spine (P = 0.79), hip (P = 0.44), and femoral neck (P = 0.34) were not different between the HIV and control groups over 2 yr. In the HIV group, longitudinal changes in BMD were not associated with current protease inhibitor, nucleoside reverse transcriptase inhibitor, or non-nucleoside reverse transcriptase inhibitor use but were associated with CD4 count, weight, FSH, N-telopeptide of type 1 collagen, and baseline BMD.

CONCLUSIONS

BMD is reduced at the spine, hip, and femoral neck among women with HIV in relationship to low weight, duration of HIV, smoking, and increased bone turnover. Over 2 yr of follow-up, BMD remained stable but lower in HIV-infected women, compared with control subjects.

A potential role for vitamin D on HIV infection?

Despite advances in the knowledge of vitamin D's potent immunomodulatory activity, its role on HIV disease progression is unknown. Decreased concentrations of 1alpha,25-hydroxyvitamin D3, or 1,25(OH)2D, the active form of vitamin D, have been reported among HIV-infected people and attributed to defects in renal hydroxylation and increased utilization. A few studies also described low levels of 25-hydroxyvitamin D3, 25(OH)D, the vitamin obtained from solar synthesis and diet. An inverse association between 1,25(OH)2D concentrations and mortality has been reported from a small cohort of HIV-infected adults, and some cross-sectional studies have indicated positive correlations between 1,25(OH)2D and CD4+ cell counts. Additional observational studies are needed to confirm the associations between vitamin D status and HIV disease progression. These investigations would provide useful insights on the potential role of vitamin D supplementation to HIV-infected persons and the planning of intervention trials.

Dialyzing a patient with human immunodeficiency virus infection: what a nephrologist needs to know

The percentage of dialysis centers that have reported dialyzing human immunodeficiency virus (HIV)-infected patients increased from 11% in 1985 to 37% in 2000. Being primary care physicians for the dialysis patients, nephrologists are frequently confronted with the management of HIV-infected dialysis patients especially in urban centers. The aims of the present review are to discuss issues that are unique to HIV infection and end-stage renal disease, and to provide dialysis caretakers with sufficient information to help them optimize care and improve outcomes of these patients. Issues related to the choice of renal replacement therapy, vascular access, management of anemia, vaccination, and antiretroviral therapies are discussed in detail.

Decreased bone mineral density in HIV-infected patients is independent of antiretroviral therapy

OBJECTIVE

To describe the alterations in the bone metabolism of HIV-seropositive patients and evaluate the effects of antiretroviral therapies.

DESIGN

Cross-sectional analytical study.

METHOD AND MATERIALS

A total of 142 subjects (113 male, 29 female), aged 20-45 years were divided into four groups: group A, 33 HIV-seropositive antiretroviral-naive patients; group B1, 36 HIV-seropositive patients on antiviral therapy for over 1 year, without protease inhibitors (PI); group B2, 42 HIV-seropositive patients on combined therapy containing PI for over 1 year; and group C, 15 healthy, HIV-seronegative subjects. Bone mineral density (BMD) were determined by dual energy X-ray absorptiometry in total body, lumbar spine and proximal femur; and evaluation of serum osteocalcin, d-pyridinoline, parathyroid hormone (THP), calcium and phosphate, and urine calcium.

RESULTS

BMD was significantly lower in HIV-seropositive patients in comparison with healthy controls, in all sites studied. However, no statistical differences were observed among all groups of HIV-infected patients, independently of the antiretroviral therapy. There was a significantly higher occurrence of osteopenia and osteoporosis in HIV-infected patients in comparison with controls (P < 0.0001), with no differences among treatment-naive patients and either of the treatment groups. Bone formation and resorption markers were similar among all studied groups. There was a significant correlation in all bone sites between time of infection and BMD (P < 0.02).

CONCLUSIONS

BMD was significantly lower in HIV-seropositive patients in comparison with controls in lumbar spine, proximal femur and total body, without significant differences among treatment-naive patients and either of the treatment groups. Only time with HIV infection and not specific therapy was associated with BMD decreases.

HIV infection--a risk factor for osteoporosis

Osteopenia and osteoporosis have recently been described as complications of antiretroviral therapy in HIV-infected patients. The advent of highly active antiretroviral therapy in conjunction with improved standard antiviral and antibiotic regimens has dramatically changed the clinical course of HIV infection, resulting in prolonged survival. The pathogenesis and role of each individual medication are poorly understood. Avascular necrosis has also been described in AIDS patients receiving or not receiving antiretroviral therapy. This article is a clinically focused review of the literature on osteopenia, osteoporosis, and mineral metabolism related to HIV infection. In patients with HIV infection, the risks of osteopenia and osteoporosis are not very clear. The suggested risk factors for the development of osteopenia are use of protease inhibitors, longer duration of HIV infection, high viral load, high lactate levels, low bicarbonate levels, raised alkaline phosphatase level, and lower body weight before antiretroviral therapy. There have also been a few case reports of pathologic fractures in AIDS patients with antiretroviral therapy-induced osteopenia and osteoporosis. The underlying mechanism triggering bone loss in HIV-infected patients is unknown. The proinflammatory cytokines tumor necrosis factor and interleukin-6 have been found to be constitutionally produced in increased amounts in HIV-positive individuals, and they may have a role in osteoclast activation and resorption. Serum markers of bone formation are decreased and resorption is increased in patients with advanced clinical disease. Hypocalcemia, hypercalcemia, and abnormalities of the parathyroid hormone axis have been described in HIV infection. Histomorphometric analyses have shown altered bone remodeling in HIV-infected patients when compared with controls. Patients with known risk factors for osteoporosis-advancing age, low body weight, and prolonged duration of HIV infection-and those receiving protease inhibitor treatment should be considered for dual x-ray absorptiometry imaging. If bone mineral density is osteopenic or osteoporotic, then the patient should also be screened for other known medical causes of osteoporosis and consider treatment with a bisphosphonate or, if hypogonadal, testosterone replacement under close monitoring.

Altered bone metabolism in children infected with human immunodeficiency virus

AIM

Data on bone homoeostasis of children infected with human immunodeficiency virus (HIV), at the time of the gain in bone mass, are very rare. To determine possible alterations in bone metabolism, 13 prepubertal vertically HIV-infected children were studied.

METHODS

Viral load, CD4 count, interleukin-6 (IL-6), growth hormone, insulin-like growth factor-I (IGF-I), IGF binding protein-3 (IGFBP-3), acid-labile subunit (ALS), IGFBP-3 proteolysis, osteocalcin in blood and N-terminal telopeptide of type I collagen in urine were determined. Lumbar spine bone mineral density was examined by dual-energy X-ray absorptiometry.

RESULTS

Low osteocalcin levels were found in all patients. Low IGF-I was found in only six children, who had low CD4 count and high IL-6 levels, with normal levels of IGFBP-3 and ALS, absent IGFBP-3 proteolysis and decreased bone mineral density, irrespective of viral load or growth.

CONCLUSION

Low serum osteocalcin levels appear to be an initial warning sign of possible altered bone metabolism in HIV-infected children. However, only when the immune system becomes more seriously compromised is bone loss measurable by bone densitometry.

Osteopenia in HIV-infected women prior to highly active antiretroviral therapy

BACKGROUND AND OBJECTIVES

Multiple endocrine and metabolic consequences of human immunodeficiency (HIV) infection exist that alter bone metabolism in patients with acquired immune deficiency syndrome (AIDS). Osteopenia in AIDS patients has been associated with antiretroviral therapy particularly with protease inhibitors. However, there is very little data on bone metabolism in female subjects with AIDS prior to highly active antiretroviral therapy.

METHODS

Bone mineral density (BMD) was assessed by dual-energy X-ray absorptiometry (DEXA) in 50 HIV-infected female outpatients (mean age 37 years) both in the lumbar spine and the Ward's triangle of the left hip. Additional parameter assessed were demographics, smoking, CD4 counts, fasting metabolic parameters and biochemical markers of bone metabolism. None of the patients received reverse transcriptase inhibitors or protease inhibitors, vitamin D or calcium-supplementation.

RESULTS

The serum levels of parathyroid hormone and 1,25-dihydroxyvitamin D (1,25(OH2)D) were significantly reduced compared to 50 age-matched female healthy controls. Urinary calcium and pyridinium crosslinks-excretion corrected for creatinine excretion were elevated (P<0.01) and were likewise significantly correlated with the loss of CD4 cells (P<0.05). Serum osteocalcin was significantly lowered (P<0.01). Reduced BMD of the lumbar spine (t -score <-2.5 SD below normal) was found in seven patients (14%) and osteopenia (t -score -1.0 to -2.5 SD below normal) was diagnosed in 31 (62%). No patient had a fracture since being infected with HIV. The BMD was reduced both in lumbar spine and the hip measured in the left Ward's triangle. There were significant positive correlation between the CD4 counts and 1,25(OH2)D (P<0.05). Neither the CD4 counts nor the duration of disease correlated with BMD. The reduced bone formation rate was linked to progressive loss of CD4-cell count.

CONCLUSION

Osteopenia in HIV-infected female subjects is commonly manifested both in lumbar spine and Ward's triangle of the hip. There is a dissociation between lowered markers of bone formation rate and the increased bone resorption expressed as elevated urinary crosslinks and calcium excretion. Furthermore, the decreased levels of 1,25(OH2)D may contribute to a negative calcium balance and inhibition of bone formation. Our results suggest that further research is necessary to determine, whether low levels of 1,25(OH2)D lead to an accelerated inflammatory process in AIDS, since 1,25(OH)2D is known as an endogenous immune modulator suppressing formation of activated T cells and cell proliferation.

The transcriptional response of human macrophages to murabutide reflects a spectrum of biological effects for the synthetic immunomodulator

The synthetic immunomodulator murabutide (MB) presents multiple biological activities with minimal toxicity in animals and in man. Although MB is known to target cells of the reticuloendothelial system and to regulate cytokine synthesis, the molecular mechanisms underlying several of its biological effects are still largely unknown. In an effort to define cellular factors implicated in the immunomodulatory and HIV-suppressive activities of MB, we have undertaken profiling the regulated expression of genes in human monocyte-derived macrophages (MDM) following a 6-h stimulation with this synthetic glycopeptide. Oligonucleotide microarray analysis was performed on RNA samples of differentiated MDM from four separate donors, using probe sets corresponding to 1081 genes. We have identified, in a reproducible fashion, the enhanced expression of 40 genes and the inhibition of 16 others in MB-treated MDM. These regulated genes belonged to different families of immune mediators or their receptors, transcription factors and kinases, matrix proteins and their inhibitors, ion channels and transporters, and proteins involved in cell metabolic pathways. Additional verification of the regulated expression of selected genes was carried out using Northern blots or the quantification of released proteins in MDM cultures. The profile of MB-regulated genes in MDM provides a molecular basis for some of its previously reported biological activities, and reveals new set of genes targeted by the immunomodulator suggesting potential application in novel therapeutic indications.

The metabolic puzzle during the evolution of HIV infection

Abnormalities in energy, protein, lipid and glucose metabolism have been described in HIV patients since the beginning of the epidemic. With the new antiretroviral agents, nutritional status and survival have improved dramatically. However, since these therapies were introduced, there have been more descriptions of metabolic abnormalities, some of which were similar to and others of which were in conflict with those reported in previous years. This paper reviews the complexity of the metabolic abnormalities in HIV infections before and after the introduction of highly active antiretroviral therapy, and discusses such etiopathogenic mechanisms as secondary infections, antiretroviral drugs and persistent immune activation, which may be involved in these derangements.

Metabolic complications associated with antiretroviral therapy

Mortality rates in the HIV-infected patient population have decreased with the advent of highly active antiretroviral therapy (HAART) for the treatment of AIDS. Due to the chronic nature of HAART, long-term metabolic complications are associated with therapy, such as hyperlipidemia, fat redistribution and diabetes mellitus. Currently, all of these symptoms are classified as the lipodystrophy (LD) syndrome(s). However, hyperlipidemia and fat redistribution occur independently, indicating there may be multiple syndromes associated with HAART. Although fat gain/loss and dyslipidemia occur in protease inhibitor (PI) naïve patients treated with nucleoside reverse transcriptase inhibitors (NRTIs), combination therapies (PI and NRTI) accelerate the syndrome. Recent clinical trials, cell culture and animal studies indicate that these effects are not drug class specific and select PIs, NRTIs and non-nucleoside reverse transcriptase inhibitors (NNRTIs) can be associated with metabolic complications. Moreover, the effects can vary between various members of the same class of antiretroviral agents (i.e. not all PIs cause the same adverse reactions) and may be influenced by duration of infection, genetics and environmental factors. Although HAART increases the risk of metabolic complications, this does not outweigh the benefits of survival. In this review, we summarize the latest clinical and scientific information on these metabolic complications, examine current hypotheses explaining the syndromes and comment on the existing methods available to manage these metabolic side effects.