Valid treatment options for osteoporosis and osteopenia in HIV-infected persons

The HIV co-receptor CCR5 regulates osteoclast function

C–C chemokine receptor 5 (CCR5) is a co-receptor of HIV. Epidemiological findings suggest that the functional loss of CCR5 is correlated with a lower incidence of bone-destructive diseases as well as of HIV transmission. However, it is not clear whether CCR5 is involved in regulation of the function of bone cells, in addition to that of immune cells. Here we show that blockade of CCR5 using specific antibodies impairs human osteoclast function in vitro. Ccr5-deficient (Ccr5^−/−) mice presented with dysfunctional osteoclasts and were resistant to osteoporosis induced by receptor activator of nuclear factor kappa-B ligand (RANKL), which triggers osteoporosis independently of inflammatory and immunomodulatory pathways. Furthermore, Ccr5 deficiency impairs the cellular locomotion and bone-resorption activity of osteoclasts, which is associated with the disarrangement of podosomes and adhesion complex molecules including Pyk2. Overall, the data provides evidence that CCR5 has an essential role in bone-destructive conditions through the functional regulation of osteoclasts.

CCR5 is a co-receptor for HIV, and loss of function is associated with lower incidence of HIV but also with bone-destructive diseases. Here the authors show that ablation of CCR5 impairs osteoclast function and improves resistance to osteoporosis in mouse models.

Management of bone mineral density in HIV-infected patients

INTRODUCTION

Loss of bone mineral density is an emerging problem in persons living with HIV infection. Earlier and more rapid bone demineralization has been attributed not only to the high prevalence of traditional risk factors, but also to specific HIV-related factors. The aim of this guidance is to stimulate an appropriate management of osteoporosis in this population, to identify patients at risk and to better manage them.

AREAS COVERED

Appropriate screening of HIV-infected subjects to identify those at risk for bone fractures is described, as well as the recommended interventions. American and European recommendations in HIV-infected and non-infected populations were considered. As the etiology of bone loss is multifactorial, many factors have to be addressed. Overall, recommendations on traditional risk factors are the same for HIV-infected and non-HIV-infected subjects. However, we should consider some specific factors in the HIV-infected population, including an appropriate antiretroviral therapy in patients with low bone mineral density, and probably novel strategies that could provide an additional benefit, such as anti-inflammatory drugs, although data supporting this approach are scant.

EXPERT OPINION

Some personal opinions are highlighted on the management of bone health in HIV-infected subjects, mainly on the use of FRAX(®) score and DXA scans. In addition, the need to implement new strategies to delay demineralization is remarked upon.

Recommendations for evaluation and management of bone disease in HIV

Thirty-four human immunodeficiency virus (HIV) specialists from 16 countries contributed to this project, whose primary aim was to provide guidance on the screening, diagnosis, and monitoring of bone disease in HIV-infected patients. Four clinically important questions in bone disease management were identified, and recommendations, based on literature review and expert opinion, were agreed upon. Risk of fragility fracture should be assessed primarily using the Fracture Risk Assessment Tool (FRAX), without dual-energy X-ray absorptiometry (DXA), in all HIV-infected men aged 40-49 years and HIV-infected premenopausal women aged ≥40 years. DXA should be performed in men aged ≥50 years, postmenopausal women, patients with a history of fragility fracture, patients receiving chronic glucocorticoid treatment, and patients at high risk of falls. In resource-limited settings, FRAX without bone mineral density can be substituted for DXA. Guidelines for antiretroviral therapy should be followed; adjustment should avoid tenofovir disoproxil fumarate or boosted protease inhibitors in at-risk patients. Dietary and lifestyle management strategies for high-risk patients should be employed and antiosteoporosis treatment initiated.

Optimal diagnostic measures and thresholds for hypogonadism in men with HIV/AIDS: comparison between 2 transdermal testosterone replacement therapy gels

OBJECTIVES

To determine the incidence of hypogonadism in men with human immunodeficiency virus (HIV)/acquired immunodeficiency virus (AIDS), the most useful serum testosterone measurement and threshold for diagnosing hypogonadism, and the comparative efficacy of 2 testosterone replacement therapy (TRT) 1% gels (AndroGel® [Abbott Laboratories] and Testim® [Auxilium Pharmaceuticals, Inc.]).

DESIGN AND SUBJECTS

This was a 2-stage observational study. In stage 1, patient records from 2 medical practices specializing in HIV/AIDS were reviewed. Eligible patients were aged ≥ 18 years; had HIV-seropositive status confirmed by enzyme-linked immunosorbent assay and western blot test or HIV-1 viremia confirmed by HIV-1 RNA polymerase chain reaction; and had prior baseline testosterone assessments for hypogonadism (ie, presence of signs/symptoms of hypogonadism as well as total testosterone [TT] and free testosterone [FT] level measurements). Stage 2 included the evaluation of patients from stage 1 who were treated with 5 to 10 g/day of TRT. The stage 2 inclusion criteria were a diagnosis of low testosterone (defined as TT level < 300 ng/dL and/or FT level < 50 pg/mL, as per The Endocrine Society guidelines and presence/absence of hypogonadal signs and symptoms); ≥ 12 months of evaluable sign and symptom assessments and TT/FT level measurements while on TRT with either Testim® or AndroGel®; and ≥ 4 weeks on initial TRT if the initial TRT was switched or discontinued.

RESULTS

Four hundred one of 422 patients met the stage 1 inclusion criteria and 167 of 401 patients (AndroGel®, n = 92; Testim®, n = 75) met the stage 2 inclusion criteria. Total testosterone level < 300 ng/dL alone identified 24% (94 of 390) of patients as hypogonadal, but failed to diagnose an additional 111 patients (67.7%) with FT levels < 100 pg/mL and hypogonadal symptoms. Through month 12, AndroGel® increased mean TT levels by +42.8% and FT levels by +66.9%, compared with +178.7% (P = 0.017) and +191% (P = 0.039), respectively, for Testim®. Patients treated with Testim® showed significantly greater improvements in libido, sexual performance, nighttime energy, focus/concentration, and abdominal girth, and trends for greater improvement in fatigue and erectile dysfunction than patients treated with AndroGel®. No patients discontinued therapy due to adverse events.

CONCLUSION

The most useful serum testosterone measurement and threshold for diagnosing hypogonadism in men with HIV/AIDS was FT level < 100 pg/mL, which identified 64% of men as hypogonadal with the presence of ≥ 1 hypogonadal symptom. This is above currently accepted thresholds. Criteria using TT level < 300 ng/dL and FT level < 50 pg/mL only diagnosed 24% and 19% of patients, respectively, as having hypogonadism. Testim® was more effective than AndroGel® in increasing TT and FT levels and improving hypogonadal symptoms.

Vitamin D deficiency and its association with low bone mineral density, HIV-related factors, hospitalization, and death in a predominantly black HIV-infected cohort

BACKGROUND

Low bone mineral density (BMD) is common among patients infected with human immunodeficiency virus (HIV) and present in higher rates in black subjects. This study assessed vitamin D levels in HIV cases versus noninfected matched controls to determine if deficiency was associated with BMD and HIV clinical outcomes.

METHODS

In total, 271 military beneficiaries with HIV underwent dual energy x-ray absorptiometry (DEXA) screening in 2001-2. Serum 25OH-vitamin D levels were determined using stored serum from the time of DEXA and 6-18 months prior. Two non-HIV-infected controls for each active duty case (n = 205) were matched on age, sex, race, zip code, and season using the Department of Defense Serum Repository (DoDSR). Vitamin D levels <20 ng/mL were considered deficient. HIV-related factors and clinical outcomes were assessed using data collected in the DoD HIV Natural History study.

RESULTS

In total, 165 of 205 (80.5%) active duty HIV cases had 2 matched controls available. HIV cases had greater odds of for vitamin D deficiency (VDD) compared with controls (demographics adjusted paired data odds ratio [OR], 1.46, 95% confidence interval [CI], .87-2.45), but this was not statistically significant. Blacks were disproportionately deficient (P <.001) but not relative to HIV status or BMD. Low BMD was associated with typical risk factors (low body mass index and exercise levels, alcohol use); given limited available data the relationship between tenofovir exposure and VDD or low BMD could not be determined. Analysis of HIV-specific factors and outcomes such as exposure to antiretrovirals, HIV progression, hospitalizations, and death revealed no significant associations with vitamin D levels.

CONCLUSIONS

VDD was highly prevalent in black HIV- infected persons but did not explain the observed racial disparity in BMD. Vitamin D deficiency was not more common among HIV- infected persons, nor did it seem associated with HIV- related factors/clinical outcomes.

Vitamin D status in young HIV infected women of various ethnic origins: incidence of vitamin D deficiency and possible impact on bone density

BACKGROUND

Decreased bone mineral density (BMD) was reported in HIV infected patients. Mechanisms leading to this decrease are poorly understood.

AIMS

To assess factors relating to BMD in young HIV infected Israeli women of Ethiopian and Caucasian origin.

PATIENTS AND METHODS

75 young HIV infected women aged 34.5 ± 8.5 followed up at the Institute of Allergy, Clinical Immunology & AIDS filled a questionnaire about sun exposure, daily calcium intake and dress habits. Data about HIV status and treatment regimens were collected from the patients' charts. Serum hydroxyvitamin D [25(OH)D] levels, bone turnover markers and bone densitometry were evaluated.

RESULTS

28 (65%) of Ethiopians and 2 (6.25%) of Caucasians had 25(OH)D serum levels <10 ng/ml (vitamin D deficiency), p = 0.001. 21 (67.7%) Ethiopians and 16 (39%) Caucasians avoided sun exposure, p = 0.019. Mean daily calcium intake was 491 ± 268.6 mg and 279 ± 252.6 mg, respectively, p = 0.001. Z scores < -1 found at Lumbar spine in 26 (89.7%), at Femoral neck in 20 (69%) at Total hip in 17 (58.6%) of vitamin D deficient patients compared to 20 (48.8%), 17 (41.5%), 9 (22%), in patients with 25(OH)D > 10 ng/ml, p < 0.01, <0.03, <0.001, respectively. Significantly more Ethiopian than Caucasian women covered their face (32.3% and 9.5%, p = 0.003) and hands (58.1% and 30.9%, p = 0.03). There was no difference in bone turnover markers levels.

CONCLUSION

Poorer vitamin D status was observed in Ethiopian women might be one of the important factors related to lower BMD in this group.

Osteoporosis and Vitamin D Deficiency in HIV-Positive Patients

Objective:

To review the epidemiology and pathophysiology of osteoporosis in patients with HIV infection and discuss vitamin D deficiency and the treatment of HIV-positive patients with osteoporosis.

Data Sources:

A search of PubMed (1980–June 2011) was conducted using the terms osteoporosis, HIV, vitamin D deficiency, and treatment.

Study Selection and Data Extraction:

Epidemiologic studies, clinical trials, and meta-analyses published in English were included. A manual review of the bibliographies of available literature was conducted and relevant articles were reviewed for inclusion.

Data Synthesis:

Patients with HIV infection are living longer with the use of potent antiretroviral therapy (ART) and are at increased risk for osteoporosis. Several studies have shown that HIV infection can affect bone health and increase the risk for osteoporosis. In addition, ART, and tenofovir in particular, may affect bone turnover. Studies and meta-analyses have shown an increased prevalence of osteopenia and osteoporosis in HIV-positive patients compared to noninfected controls. Recent reports also show increased prevalence of fractures and low vitamin D concentrations in HIV-positive patients. Osteoporosis treatments used in patients with HIV infection are similar to treatments for noninfected patients. HIV-positive patients should be monitored and treated to prevent the progression and complications of osteoporosis.

Conclusions:

HIV-positive patients are at increased risk for osteoporosis and vitamin D deficiency due to disease and treatment influences on bone health. These patients should be identified and treated to prevent the morbidity and mortality associated with osteoporosis.

Moving from viral suppression to comprehensive patient-centered care: the high prevalence of comorbid conditions and health risk factors in HIV-1-infected patients in Australia

HIV clinicians today need to move from focusing on viral suppression to a chronic disease model in which comorbid conditions and risk factors are comprehensively identified and addressed to reduce rates of serious non-AIDS-related morbidity and mortality. This study aimed to determine the prevalence of comorbid conditions in an Australian HIV-positive population. Of 180 patients included, there was a median CD4 count of 0.520 cells/mm(3). The majority (88%) of patients were currently receiving highly active antiretroviral therapy (HAART). There were high rates of failure to attend clinical appointments (30%), current smoking (42%), hypertension (16%), and dyslipidemia (17%). Significant rates of dipstick-positive proteinuria (16%) and elevated blood glucose (15%) were recorded. Risk factors were commonly not addressed by the treating clinician. There is an urgent need to systematize detection and management of high-prevalence comorbid conditions to prevent premature mortality associated with serious non-AIDS events.

Osteoimmunopathology in HIV/AIDS: A Translational Evidence-Based Perspective

Infection with the human immunodeficiency virus-1 (HIV) and the resulting acquired immune deficiency syndrome (AIDS) alter not only cellular immune regulation but also the bone metabolism. Since cellular immunity and bone metabolism are intimately intertwined in the osteoimmune network, it is to be expected that bone metabolism is also affected in patients with HIV/AIDS. The concerted evidence points convincingly toward impaired activity of osteoblasts and increased activity of osteoclasts in patients with HIV/AIDS, leading to a significant increase in the prevalence of osteoporosis. Research attributes these outcomes in part at least to the ART, PI, and HAART therapies endured by these patients. We review and discuss these lines of evidence from the perspective of translational clinically relevant complex systematic reviews for comparative effectiveness analysis and evidence-based intervention on a global scale.

HIV-1 infection and antiretroviral therapies: risk factors for osteoporosis and bone fracture

PURPOSE OF REVIEW

Patients with HIV-1 infection/AIDS are living longer due to the success of highly active antiretroviral therapy (HAART). However, serious metabolic complications including bone loss and fractures are becoming common. Understanding the root causes of bone loss and its potential implications for aging AIDS patients will be critical to the design of effective interventions to stem a tidal wave of fractures in a population chronically exposed to HAART.

RECENT FINDINGS

Paradoxically, bone loss may occur not only due to HIV/AIDS but also as a consequence of HAART. The cause and mechanisms driving these distinct forms of bone loss, however, are complex and controversial. This review examines our current understanding of the underlying causes of HIV-1 and HAART-associated bone loss, and recent findings pertaining to the relevance of the immuno-skeletal interface in this process.

SUMMARY

It is projected that by 2015 more than half of the HIV/AIDS population in the USA will be over the age of 50 and the synergy between HIV and/or HAART-related bone loss with age-associated bone loss could lead to a significant health threat. Aggressive antiresorptive therapy may be warranted in high-risk patients.

Aging, human immunodeficiency virus, and bone health

Highly active antiretroviral therapy (HAART) has had a profound impact on improving the long-term prognosis for individuals infected with human immunodeficiency virus (HIV). HAART has been available for close to two decades, and now a significant number of patients with access to HAART are over the age of 50 years. Many clinical studies have indicated that HIV infection, as well as components of HAART, can increase the risk in these individuals to a variety of noninfectious complications, including a risk to bone health. There is a significant need for detailed mechanistic analysis of the aging, HIV-infected population regarding the risk of HIV infection and therapy in order to maintain bone health. Insights from basic mechanistic studies will help to shed light on the role of HIV infection and the components of HAART that impact bone health, and will help in identifying preventative countermeasures, particularly for individuals 50 years of age and older.

Micronutrients and HIV infection

The immune system requires several essential micronutrients to maintain an effective immune response. HIV infection destroys the immune system and promotes nutritional deficiencies, which further impair immunity. This article reviews the role of several micronutrients (vitamins A, C, E and D, the B vitamins, and minerals, selenium, iron and zinc) that are relevant for maintaining immune function. In addition, the deficiencies of these micronutrients have been associated with faster progression of HIV-1 disease. This review examines the evidence from observational studies of an association between micronutrient status and HIV disease, as well as the effectiveness of micronutrient supplementation on HIV-disease progression, pregnancy outcomes and nutritional status, among others, utilizing randomized clinical trials. Each micronutrient is introduced with a summary of its functions in human physiology, followed by the presentation of studies conducted in HIV-infected patients in relation to this specific micronutrient. Overall findings and recommendations are then summarized.

Current understanding of osteoporosis associated with liver disease

Osteoporosis is a common complication of many types of liver disease. Research into the pathogenesis of osteoporosis has revealed that the mechanisms of bone loss differ between different types of liver disease. This Review summarizes our current understanding of osteoporosis associated with liver disease and the new advances that have been made in this field. The different mechanisms by which cholestatic and parenchymal liver disease can lead to reduced bone mass, the prevalence of osteopenia and osteoporosis in patients with early and advanced liver disease, and the influence of osteoporotic fractures on patient survival are discussed along with the advances in our understanding of the molecular pathways associated with bone loss. The role of the CSF1-RANKL system and that of the liver molecule, oncofetal fibronectin, a protein that has traditionally been viewed as an extracellular matrix protein are also discussed. The potential impact that these advances may have for the treatment of osteoporosis associated with liver disease is also reviewed.

Impact of metabolic complications on antiretroviral treatment adherence: clinical and public health implications

Antiretroviral therapy (ART) is an effective strategy for preventing disease progression of HIV infection, particularly when patients adhere closely to the treatment regimen. However, ART medications can cause side effects, including metabolic complications that can impact patients' adherence levels. Selected chronic complications associated with ART include lipodystrophy, hyperlipidemia, insulin resistance and diabetes, peripheral neuropathy, and bone disorders such as osteopenia/osteoporosis. In this article, we review the effects of these metabolic complications on ART adherence and approaches to prevent or reverse them.

A double-blinded, randomized controlled trial of zoledronate therapy for HIV-associated osteopenia and osteoporosis

OBJECTIVE

To evaluate the efficacy of a single dose of intravenous zoledronate for the treatment of HIV-associated osteopenia and osteoporosis.

DESIGN

A double-blinded, randomized, placebo-controlled, 12-month trial of 5 mg intravenous zoledronate dose to treat 30 HIV-infected men and women with osteopenia and osteoporosis.

METHODS

Following zoledronate or placebo infusions, participants were followed for 12 months on daily calcium and vitamin D supplements. Lumbar spine and hip bone density was assessed at baseline, 6 and 12 months. Biomarkers of bone metabolism were measured at baseline, 2 weeks, 3, 6, 9, and 12 months. Student's t-test and repeated measure analyses were used to evaluate bone density and bone marker changes over time.

RESULTS

In the 30 HIV-infected individuals [men (27) and women (3)] in the trial, median T-scores at entry were -1.7 for the lumbar spine and -1.4 for the hip. Median CD4 cell count was 461 cells/microl, 93% had HIV-RNA viral loads less than 400 copies/ml, and 97% were taking antiretroviral medications. Bone density measured either absolutely or as sex-adjusted T-scores significantly improved in zoledronate recipients as compared with minimal changes in those receiving placebo. Bone resorption markers significantly decreased over the study period in the zoledronate recipients as compared with placebo controls. No acute infusion reactions were detected, but one patient developed uveitis, a recognized complication of zoledronate, which responded to therapy.

CONCLUSION

In this small study, annual zoledronate appears to be a well tolerated and effective therapy for HIV-associated bone loss.

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.