Body composition changes in protease inhibitor-naive HIV-infected patients treated with two nucleoside reverse transcriptase inhibitors

Sarcopenia risk, sarcopenia-related quality of life, and associated factors in people living with human immunodeficiency virus (HIV): A web-based survey

OBJECTIVES

We aimed to screen for the risk of sarcopenia and sarcopenia-related quality of life and associated factors of people living with HIV (PLWH).

RESEARCH METHODS AND PROCEDURES

This nonprobabilistic web-based survey evaluated PLWH. The participants were invited directly from a university-based inpatient clinic and responded to a web questionnaire that included the SARC-F and SarQoL to screen people at risk of sarcopenia and their quality of life. People at risk of sarcopenia were defined by the proposed cutoff points for SARC-F (≥ 4 points), and SarQoL overall score was categorized according to the median. Moreover, we performed a logistic regression to investigate associations between HIV-, lifestyle-, and health-associated factors (i.e., physical activity, dietary pattern, sleep quality, gastrointestinal symptoms, HIV diagnosis, type, combinations, and duration of ART, smoking, drinking, BMI, and weight loss), and outcomes (SARC-F and SarQoL).

RESULTS

The sample comprised 202 PLWH, mainly middle-aged (50.6-60.5 y; n = 101). Only 5.9% (n = 12) are at risk of sarcopenia according to SARC-F, and only 17.3% (n = 35) exhibited lower sarcopenia-related quality of life according to SarQoL. In the multiple models, only the gastrointestinal symptoms increased the odds of sarcopenia risk (OR: 1.058; P = 0.01) and poor sarcopenia-associated quality of life (OR: 1.041; P = 0.013).

CONCLUSIONS

We verified that only 5.9% and 17.3% of PLWH are at risk of sarcopenia and presented lower sarcopenia-related quality of life, respectively. Only the gastrointestinal symptoms were associated with a risk of sarcopenia and lower sarcopenia-related quality of life, without significant differences between age groups.

Perspectives on menopause and women with HIV

Since the implementation of effective combination antiretroviral therapy, HIV infection has been transformed from a life-threatening condition into a chronic disease. As people with HIV are living longer, aging and its associated manifestations have become key priorities as part of HIV care. For women with HIV, menopause is an important part of aging to consider. Women currently represent more than one half of HIV-positive individuals worldwide. Given the vast proportion of women living with HIV who are, and will be, transitioning through age-related life events, the interaction between HIV infection and menopause must be addressed by clinicians and researchers. Menopause is a major clinical event that is universally experienced by women, but affects each individual woman uniquely. This transitional time in women's lives has various clinical implications including physical and psychological symptoms, and accelerated development and progression of other age-related comorbidities, particularly cardiovascular disease, neurocognitive dysfunction, and bone mineral disease; all of which are potentially heightened by HIV or its treatment. Furthermore, within the context of HIV, there are the additional considerations of HIV acquisition and transmission risk, progression of infection, changes in antiretroviral pharmacokinetics, response, and toxicities. These menopausal manifestations and complications must be managed concurrently with HIV, while keeping in mind the potential influence of menopause on the prognosis of HIV infection itself. This results in additional complexity for clinicians caring for women living with HIV, and highlights the shifting paradigm in HIV care that must accompany this aging and evolving population.

Detection of hepatotoxicity potential with metabolite profiling (metabolomics) of rat plasma

While conventional parameters used to detect hepatotoxicity in drug safety assessment studies are generally informative, the need remains for parameters that can detect the potential for hepatotoxicity at lower doses and/or at earlier time points. Previous work has shown that metabolite profiling (metabonomics/metabolomics) can detect signals of potential hepatotoxicity in rats treated with doxorubicin at doses that do not elicit hepatotoxicity as monitored with conventional parameters. The current study extended this observation to the question of whether such signals could be detected in rats treated with compounds that can elicit hepatotoxicity in humans (i.e., drug-induced liver injury, DILI) but have not been reported to do so in rats. Nine compounds were selected on the basis of their known DILI potential, with six other compounds chosen as negative for DILI potential. A database of rat plasma metabolite profiles, MetaMap(®)Tox (developed by metanomics GmbH and BASF SE) was used for both metabolite profiles and mode of action (MoA) metabolite signatures for a number of known toxicities. Eight of the nine compounds with DILI potential elicited metabolite profiles that matched with MoA patterns of various rat liver toxicities, including cholestasis, oxidative stress, acetaminophen-type toxicity and peroxisome proliferation. By contrast, only one of the six non-DILI compounds showed a weak match with rat liver toxicity. These results suggest that metabolite profiling may indeed have promise to detect signals of hepatotoxicity in rats treated with compounds having DILI potential.

Bone mineral density in children and adolescents with perinatal HIV infection

OBJECTIVE

To estimate prevalence of low bone mineral density (BMD) in perinatally HIV-infected (HIV+) and HIV-exposed but uninfected (HEU) children, and to determine predictors of BMD in HIV+.

DESIGN

Cross-sectional analysis within a 15-site United States and Puerto Rico cohort study.

METHODS

Total body and lumbar spine BMD were measured using dual energy-X-ray absorptiometry. BMD Z-scores accounted for bone age and sex. Multiple linear regression was used to evaluate differences in Z-scores by HIV status and for predictors of BMD in HIV+.

RESULTS

350 HIV+ and 160 HEU were enrolled. Mean age was 12.6 and 10.7 years for HIV+ and HEU, respectively. Most (87%) HIV+ were receiving HAART. More HIV+ than HEU had total body and lumbar spine Z-scores less than -2.0 (total body: 7 vs. 1%, P = 0.008; lumbar spine: 4 vs. 1%, P = 0.08). Average differences in Z-scores between HIV+ and HEU were attenuated after height and/or weight adjustment. Among HIV+, total body Z-scores were lower in those with higher CD4% and in those who ever used boosted protease inhibitors or lamivudine. Lumbar spine Z-scores were lower with higher peak viral load and CD4%, more years on HAART, and ever use of indinavir.

CONCLUSION

Rates of low BMD in HIV+ children were greater than expected based on normal population distributions. These differences were partially explained by delays in growth. As most HIV+ children in this study had not entered their pubertal growth spurt, prepubertal factors associated with BMD, magnified or carried forward, may result in sub-optimal peak BMD in adulthood.

The frequency of low muscle mass and its overlap with low bone mineral density and lipodystrophy in individuals with HIV--a pilot study using DXA total body composition analysis

As a result of the advances in antiretroviral therapy, the life span of human immunodeficiency virus (HIV)-infected patients has increased dramatically. Attendant to these effects are signs of premature aging with notable changes in the musculoskeletal system. Although changes in bone and fat distribution have been studied extensively, far less is known about changes in muscle. This study examined the extent of low muscle mass (LMM) and its relationship with low bone mineral density (BMD) and lipodystrophy (LD) in HIV-positive males. As such, HIV-positive males on therapy or treatment naive underwent dual-energy X-ray absorptiometry total body composition measurements. Appendicular lean mass/(height)2 and lowest 20% of residuals from regression analysis were used to define LMM. BMD criteria defined osteopenia/osteoporosis, and the percent central fat/percent lower extremity ratio defined LD. Several potential risk factors were assessed through chart review. Sixty-six males (57 with treatment and 9 treatment naive) volunteered. Treated individuals were older than naive (44 vs 34 yr) and had HIV longer (108 vs 14 mo). When definitions for sarcopenia (SP) in elderly individuals were applied, the prevalence of LMM was 21.9% and 18.8% depending on the definition used. Low BMD was present in 68.2% of participants. LD with a cutoff of 1.5 and 1.961 was present in 54.7% and 42.2% of participants, respectively. LMM and LD were negatively associated. In conclusion, this study shows that LMM is common in males with HIV and that SP affecting muscle function could be present in a substantial number of individuals. Future research needs to examine what impact decreased muscle mass and function has on morbidity, physical function, and quality of life in individuals with HIV.

Bone mineral density in HIV-infected women taking antiretroviral therapy: a systematic review

There is a high prevalence of osteoporosis in HIV-infected patients. Initially described in HIV-positive men, studies have also demonstrated a high prevalence of osteoporosis in HIV-infected women. It would appear that antiretroviral therapy (ART) plays an important role in the pathogenesis of osteoporosis in HIV-infected patients, although little is known about its importance in relation to osteoporosis and fractures in HIV-positive women. The aim of this systematic review was to evaluate the frequency of bone loss, bone mineral density (BMD) and fractures in HIV-positive women taking ART or protease inhibitors (PI). After screening 597 citations from the databases of PubMed, EMBASE and Lilacs, five studies were selected for the review. A difference was demonstrated of over 3% in the BMD at the femoral neck of HIV-positive women taking PI/ART. No difference was registered in the BMD at the lumbar spine between users and non-users of PI/ART. The lack of studies has made it impossible to reach any conclusion regarding the occurrence of fractures.

Age-related skeletal muscle decline is similar in HIV-infected and uninfected individuals

BACKGROUND

Skeletal muscle (SM) mass decreases with advanced age and with disease in HIV infection. It is unknown whether age-related muscle loss is accelerated in the current era of antiretroviral therapy and which factors might contribute to muscle loss among HIV-infected adults. We hypothesized that muscle mass would be lower and decline faster in HIV-infected adults than in similar-aged controls.

METHODS

Whole-body (1)H-magnetic resonance imaging was used to quantify regional and total SM in 399 HIV-infected and 204 control men and women at baseline and 5 years later. Multivariable regression identified associated factors.

RESULTS

At baseline and Year 5, total SM was lower in HIV-infected than control men. HIV-infected women were similar to control women at both time points. After adjusting for demographics, lifestyle factors, and total adipose tissue, HIV infection was associated with lower Year 5 SM in men and higher SM in women compared with controls. Average overall 5-year change in total SM was small and age related, but rate of change was similar in HIV-infected and control men and women. CD4 count and efavirenz use in HIV-infected participants were associated with increasing SM, whereas age and stavudine use were associated with decreasing SM.

CONCLUSIONS

Muscle mass was lower in HIV-infected men compared with controls, whereas HIV-infected women had slightly higher SM than control women after multivariable adjustment. We found evidence against substantially faster SM decline in HIV infected versus similar-aged controls. SM gain was associated with increasing CD4 count, whereas stavudine use may contribute to SM 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.

Evolution and predictors of change in total bone mineral density over time in HIV-infected men and women in the nutrition for healthy living study

BACKGROUND

Osteopenia is common in the era of effective antiretroviral therapy (ART), yet the etiology is unclear. We evaluated the association of host factors, disease severity, and ART to changes in total body bone mineral density (total BMD) over time in HIV-infected men (n = 283) and women (n = 96).

METHODS

Total BMD was measured annually by whole-body dual-energy absorptiometry (DXA), and medical, dietary, and behavioral history was collected. The median time from first to last DXA was 2.5 years (range 0.9-6.8 years). Using a repeated measures regression model, we identified variables independently associated with percent change in total BMD between consecutive DXA exams (n = 799 intervals), adjusted for age, race, sex, menopause, and smoking. We estimated percent change in total BMD over an average interval (1 year) standardized for representative levels of each determinant in males, premenopausal women, and postmenopausal women.

RESULTS

Median baseline age, CD4, and viral load were 42 years, 364 cells per cubic millimeter, and 2.7 log10 copies per milliliter, respectively. The estimated change in total BMD for those not on ART was -0.37% per year [95% confidence interval (CI) -0.76 to -0.02] for men, -0.08% per year (95% CI -0.49 to 0.33) for premenopausal women, and -1.07% per year (95% CI -1.86 to -0.28) for postmenopausal women. Greater loss of total BMD was associated with lower albumin, lower body mass index, prednisone/hydrocortisone use, tenofovir use, and longer duration of didanosine. Strength training and long duration of d4T and saquinavir prevented or mitigated bone loss. For those on ART for 3 years (not including the above agents), the rate of loss was -0.57% per year (95% CI -1.00 to -0.14) for men, -0.28% (95% CI -0.71 to 0.15) for premenopausal women, and -1.27% (95% CI -2.07 to -0.47) for postmenopausal women. Postmenopausal women had greater loss than premenopausal women and men.

CONCLUSIONS

Low body weight, low albumin, catabolic steroid use, and menopause may accelerate bone loss, and strength training may be protective. Tenofovir and didanosine may also have a deleterious effect on BMD.

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.

Antiretroviral therapy and the prevalence of osteopenia and osteoporosis: a meta-analytic review

INTRODUCTION

Prevalence estimates of osteopenia and osteoporosis (reduced bone mineral density; BMD) in HIV-infected patients and the role of antiretroviral therapy (ART) varies in the literature.

METHODS

We conducted a meta-analytical review of cross-sectional studies published in English to determine the pooled odds ratios (OR) of reduced BMD and osteoporosis in the following groups: HIV-positive versus HIV-negative; ART-treated versus ART-naive; protease inhibitor (PI)-treated versus PI-untreated. We searched the MEDLINE, PubMed, and EMBASE databases for eligible references between January 1966 and November 2005. Random effects models were used to generate pooled OR estimates and confidence intervals.

RESULTS

Of 37 articles identified, 20 met the inclusion criteria. Of the 884 HIV-infected patients, 67% had reduced BMD, of whom 15% had osteoporosis, yielding a pooled OR of 6.4 and 3.7, respectively, compared with HIV-uninfected controls (n = 654) using 11 studies with available data. Compared with ART-naive patients (n = 202, 10 studies), ART-treated individuals (n = 824) had a 2.5-fold increased odds of prevalent reduced BMD. The risk of prevalent osteoporosis (seven studies) was similarly elevated in ART-treated individuals. Compared with non-PI-treated HIV patients (n = 410, 14 studies), PI-treated patients (n = 791) had increased odds of reduced BMD and osteoporosis (12 studies). Few studies adjusted for important covariates such as HIV disease severity or treatment duration.

CONCLUSION

The prevalence of osteoporosis in HIV-infected individuals is more than three times greater compared with HIV-uninfected controls. ART-exposed and PI-exposed individuals had a higher prevalence of reduced BMD and osteoporosis compared with their respective controls. The influence of other disease and treatment variables on these estimates could not be determined.

Pathogenesis of osteopenia/osteoporosis induced by highly active anti-retroviral therapy for AIDS

The advent of highly active anti-retroviral therapy (HAART) has dramatically decreased the rate of AIDS-related mortality and significantly extended the life span of patients with AIDS. A variety of metabolic side effects are associated with these therapies, one of which is metabolic bone disease. A higher prevalence of osteopenia and osteoporosis in HIV-infected patients receiving anti-retroviral therapy than in patients not on therapy has now been reported in several studies. Several factors have been demonstrated to influence HIV-associated decreases in bone mineral density (BMD), including administration of nucleoside reverse transcriptase inhibitors (NRTIs). In this article, discussion will focus on the molecular pathogenesis and treatment of HAART-associated osteopenia and osteoporosis.

In Combination, Nucleoside Reverse Transcriptase Inhibitors Have Significant Effects on 3T3–L1 Adipocyte Lipid Accumulation and Survival

The use of nucleoside reverse transcriptase inhibitors (NRTIs) for the treatment of HIV infection is clearly linked to the development of subcutaneous fat atrophy. Until recently, however, in vitro studies of adipocytes have shown no or only modest and inconsistent effects of these agents on adipocyte biology. This is in contrast to the protease inhibitors (PIs), which are also linked to the development of HIV lipodystrophy. These agents have relatively consistent inhibitory effects on the differentiation of cultured adipocytes, and have occasionally been found to have other effects on adipocyte biology as well. We aimed to explore more thoroughly the effects of NRTIs and combinations of antiretroviral agents commonly used in clinical practice on multiple aspects of adipocyte biology using the 3T3-L1 adipocyte cell line. We found that when used individually, NRTIs decrease cell survival but only lamivudine significantly alters lipid accumulation. However, NRTI and dual NRTI-PI combinations do significantly decrease lipid accumulation in 3T3-L1 adipocytes, have a much greater detrimental impact on cell survival and decrease adipocyte differentiation.

Tolerability and safety of HIV protease inhibitors in adults

Antiretroviral drugs are associated with both short-term and long-term adverse events. Like other HIV drugs, protease inhibitors (PIs) may affect metabolic processes influencing body shape and body tissue composition, appearance, bone integrity, and cardiovascular status. However, numerous confounding variables including age, cigarette smoking, body mass index (BMI), duration of HIV infection, degree of immunodeficiency, concomitant antiretroviral agents, extent of previous treatment, and duration of treatment all blur the relationship between PI use and adverse events. Recent data suggest that the early PIs appear to have greater effects on such surrogate markers of disease risk as insulin resistance and cholesterol and triglyceride levels than the recently developed PIs. These data also suggest that evaluation of PIs as a class should be reconsidered and that it is probably not appropriate to extrapolate safety data obtained from individuals treated with first-generation agents in the era of potent combination antiretroviral therapy to those treated with recently developed PIs. Because PIs remain a critical component of successful antiretroviral therapy, evaluation of potential long-term complications with prolonged PI use is essential, as is delineation of the significant differences in safety profiles among individual PIs.

Predictors of bone mineral density in human immunodeficiency virus-1 infected children

OBJECTIVES

To compare bone mineral density (BMD) among human immunodeficiency virus (HIV)-infected children with population norms and to determine predictors of BMD in HIV-infected children.

METHODS

Total body BMD was measured by dual energy x-ray absorptiometry in 37 HIV-infected children and nine sibling controls at baseline. Clinical, dietary and anthropometric data were obtained at the time of the dual energy x-ray absorptiometry examination. Age- and gender-adjusted z scores were calculated for BMD, body mass index, weight and height from population standards. Age-adjusted percentiles were determined for dietary intake of calcium and vitamin D. Differences in BMD z scores between HIV-infected children and sibling controls were determined and adjusted for height and weight, as were independent risk factors for lower BMD among infected children. Eighteen HIV-infected children and 5 controls had serial BMD measures.

RESULTS

Compared with population norms, HIV-infected children had significantly lower BMD z scores (-0.51 SD, P = 0.004), in contrast with controls who had normal z scores (0.38 SD, P = 1.0). However, there was no difference in BMD z scores between HIV-infected children and the small number of sibling controls, adjusted for height and weight. Among HIV-infected children, lower BMD z scores were independently associated with lower weight z scores (P < 0.0001), lower height z scores (P = 0.01), advanced (stage B or C) HIV stage (P = 0.01) and age greater than 8 years (P < 0.0001). In the same model, multivitamin use (P = 0.009) and African American race (P = 0.001) were associated with better BMD z scores, with nevirapine use showing borderline positive effect (P = 0.06). All results were adjusted for Tanner stage. Change in BMD z score over time showed that there was no change or an increase in BMD in 100% of controls but in only 44% of the HIV-infected children (P = 0.09).

CONCLUSION

When compared with population norms, HIV-infected children had lower than expected bone mass for their age and gender that may be attributable to delays in growth, sexual maturity, time (length of HIV infection), ethnicity and disease severity. Dietary intake of calcium and vitamin D were not associated with bone loss, but most children had suboptimal intake. However, multivitamin use was strongly associated with better bone mineral density.

Reproducibility of DXA estimations of body fat in HIV lipodystrophy: implications for clinical research

Dual-energy X-ray absorptiometry (DXA) estimates of body fat are increasingly used for the evaluation of human immunodeficiency virus lipodystrophy (HIV LD); however, limited data are available on their reproducibility. This information is essential for using this tool as an end point in treatment trials or as a diagnostic tool. This study evaluates the reproducibility of DXA body fat estimation in HIV-positive subjects with and without lipodystrophy. Thirty subjects representing a spectrum of severity of fat redistribution underwent same-day repeat whole-body DXA scans (Hologic QDR 4500A scanner). Root mean square coefficients of variation (RMS-CV) were used to estimate minimum detectable differences (MDDs) for body fat content in different regions. Absolute MDD was calculated by multiplying the MDD by the mean fat-mass value for each anatomical area. The RMS-CV ranged from 4.0% for arm fat to 1.6% for total fat. Relative and absolute MDD values ranged from 11.0% or 160 g for arm fat to 4.3% or 628 g for total fat. DXA measurements of regional body fat mass in subjects with HIV show similar reproducibility to other populations. Minimal detectable differences were smaller than differences observed in published studies for all measurements. DXA is a sensitive tool for detecting changes in peripheral fat among patients with HIV lipodystrophy.

Body habitus in a cohort of HIV-seropositive and HIV-seronegative injection drug users

We determined anthropometric measurements (including height, weight, circumferences, and skinfolds) and self-reported symptoms related to body habitus changes in 324 HIV-seropositive and HIV-seronegative inner city injection drug users (IDUs) who participated in a substudy from the ALIVE (AIDS Linked to Intravenous Experiences) cohort. Participants who reported lipoatrophy in body parts had consistently lower anthropometric measurements and those reporting adiposity had correspondingly higher anthropometric measurements than participants who did not report these changes. Peripheral lipoatrophy was more common among all HIV-seropositive than HIV-seronegative participants, however, it was not associated with highly active antiretroviral therapy (HAART) (39% HIV-seronegatives; 58% HIV-seropositive not receiving HIV treatment [No Tx]; 49% HAART, p = 0.04). Central adiposity was more common among HAART (52%) than No Tx (26.6%) and HIV-seronegative (42%) participants (p = 0.001). However, waist circumference, while somewhat higher among HAART than No Tx participants, did not differ significantly from HIV-seronegative participants (85.2 cm HIV-seronegatives; 83.3 cm No Tx; 85.8 cm HAART). A large proportion of those who reported peripheral lipoatrophy also reported central lipoatrophy (76.9% HIV-seronegatives; 69.6% No Tx; 66.2% HAART). A large proportion of those who reported central adiposity also reported adiposity of the peripheral sites (88.1% HIV seronegatives; 66.7% No Tx; 74.3% HAART). The combination of lipoatrophy and adiposity was associated with HAART treatment (6% HIV-seronegatives; 3% No Tx; 16% HAART, p = 0.002), but may be driven by the association with adiposity. These data suggest validity of self-reports for body habitus changes among injection drug users.

Bone Disorders Associated with the Human Immunodeficiency Virus: Pathogenesis and Management

Bone disorders such as osteopenia, osteoporosis, and osteonecrosis have been reported in patients infected with the human immunodeficiency virus (HIV), but the etiology and mechanism of these disorders are unknown. The prevalence estimates vary widely among studies and may be influenced by the presence or absence of antiretroviral therapy and lipodystrophy, severity of HIV disease, and overlapping bone loss risk factors. Addressing potential underlying bone disease risk factors (e.g., smoking and alcohol intake), evaluating calcium and vitamin D intake, and performing dual x-ray absorptiometry in patients with HIV who have risks for bone disease are important strategies in preventing osteopenia and osteoporosis in HIV-infected patients. Management of osteopenia and osteoporosis is still being evaluated. Administration of bisphosphonates (e.g., alendronate), with calcium and vitamin D supplementation, may be reasonable in treating osteoporosis; however, surgical intervention is the only method for treating symptomatic osteonecrosis.

CALCIUM AND BONE MINERAL METABOLISM IN CHILDREN WITH CHRONIC ILLNESSES

Increased longevity and improved medical management of children with chronic illnesses has led to a focus on the short- and long-term consequences of these conditions on bone health. Bone loss is influenced by diet, malabsorption, and disease-related imbalances in bone turnover. It may be exacerbated by common medications, especially corticosteroids. Assessment of bone mass and quality, calcium absorption, kinetically derived rates of bone turnover, and biochemical markers of bone turnover have increased our knowledge of the pathophysiology of bone loss in these children as well as provided insights into possible therapeutic interventions. Increased intake of calcium and vitamin D, while useful, is unlikely to prevent or resolve bone loss in many chronically ill children. Emphasis on combination of nutritional interventions with exercise and newer bone-sparing therapies may be necessary.

AZT enhances osteoclastogenesis and bone loss

A variety of metabolic complications have been reported to be associated with highly active antiretroviral therapy (HAART), including osteopenia and osteoporosis. In this study, we determine the effects of zidovudine (AZT), a nucleoside reverse transcriptase inhibitor, on osteoclastogenesis in a cultured mouse macrophage preosteoclast cell line (RAW264.7), in mouse primary bone marrow macrophage-monocyte precursors, and on bone mineral density in mice. The results indicate that AZT induces an increase in osteoclastogenesis in the mouse preosteoclast cell line and in mouse bone marrow osteoclast precursors in the presence of RANKL. This increased osteoclastogenesis is dependent upon the concentration of AZT. AZT increases the promoter activity of tartrate-resistant acid phosphatase (TRAP) and the binding and function of the nuclear transcription protein, NF-kappaB, in RAW264.7 cells. Therefore, the effect of AZT is mediated, at least in part, by enhancing RANKL-mediated osteoclastogenesis. Bone mineral density (BMD) in AZT-treated mice is decreased and histopathology shows marked osteopenia. These results support an important role of AZT-stimulated osteoclastogenesis in HAART-induced osteopenia.

High Plasma Level of Interleukin-18 in HIV-Infected Subjects With Lipodystrophy

The level of interleukin-18 (IL-18) is elevated in patients with HIV infection as well as in people with insulin resistance (IR). As HIV-associated lipodystrophy (LD) shares metabolic characteristics with the metabolic syndrome, it was hypothesized that IL-18 would be elevated in patients with LD. Two groups of HIV-infected men with LD, one with fat accumulation (mixed group) (n = 12) and one without fat accumulation (lipoatrophic group) (n = 15) were included. Controls were HIV-positive men without LD (n = 15) and HIV-negative, age-matched men (n = 12). The levels of plasma IL-18 were elevated in all 3 HIV groups compared with HIV-negative controls (P <0.01). In the HIV groups the lipoatrophic group had the highest IL-18, followed by the mixed group and the HIV-positive controls. Only the differences between the lipoatrophic group and the HIV-positive controls were significant (P <0.01). Plasma IL-18 correlated with tumor necrosis factor-alpha (P <0.05), but not IL-6, adiponectin, or HOMA-IR (homeostasis model of insulin resistance). In contrast to the HIV-negative controls, IL-18 did not correlate with total or low-density cholesterol in either of the HIV groups. An inverse correlation was observed between IL-18 and limb fat (P <0.05). In conclusion, the level of IL-18 is elevated in patients with LD and closely linked to limb atrophy, whereas it is not associated with cholesterol or IR.

Low plasma level of adiponectin is associated with stavudine treatment and lipodystrophy in HIV-infected patients

This study tested the hypothesis that in patients with HIV-associated lipodystrophy, adiponectin levels were related to insulin resistance, TNF-alpha and IL-6 and treatment with nucleoside analogues. HIV seropositive men undergoing highly active antiretroviral treatment were enrolled into three predetermined clinical groups: lipodystrophy with central fat accumulation (n = 12); lipodystrophy without central fat accumulation (n = 15); no lipodystrophy (n = 15). HIV-negative healthy men served as controls (n = 12). Both lipodystrophic groups had a low percentage of limb fat compared to the two control groups. Patients with lipodystrophy with fat accumulation had increased truncal fat compared with controls. Levels of adiponectin did not correlate with either TNF-alpha or IL-6. Low levels of adiponectin were found in both lipodystrophic groups and were associated with current or previous treatment with stavudine. Furthermore, the adiponectin level correlated with the percentage of limb fat. Patients with lipodystrophy with fat accumulation were more insulin resistant, measured by HOMA-IR, compared with controls. However, HOMA-IR did no correlate to adiponectin or other cytokines. In conclusion, the finding of no difference between the two lipodystrophic groups with regard to adiponectin, indicates that low levels of adiponectin reflects fat atrophy, whereas the insulin resistance was best explained by increased truncal fat mass.

Endothelial markers and HIV infection in the era of highly active antiretroviral treatment

Many circumstances can induce activation and/or injury of the endothelium that plays a role in the development of vascular complications. Raised plasma levels of endothelial markers such as von Willebrand factor (vWF), soluble thrombomodulin (sTM) and soluble vascular cell adhesion molecule-1 (sVCAM-1) have a prognostic and/or diagnostic value. Human immunodeficiency virus-infected patients (HIV+) have a clustering of conditions that activate or injure the endothelium. Highly active antiretroviral treatment produces adverse effects such as dyslipemia, insulin resistance (IR) and body fat changes (named lipodystrophy syndrome) which may contribute to aggravate their endothelial perturbation. The aim of this study was to measure lipid profile, insulin resistance status, and endothelial markers in 38 HIV+ naive of antiretroviral treatment and 63 HIV+ under highly active antiretroviral treatment (33 with lipodystrophy syndrome and 30 without it). Body fat distribution was also evaluated by dual-energy X-ray absorptiometry (DEXA) analysis. Thirty-one HIV negative subjects were used as controls. We looked for association between variables. Insulin resistance status was a common finding in the four groups. Lipodystrophic patients presented an atherothrombotic lipid profile [elevated levels of triglycerides (TG), low-density lipoprotein cholesterol (LDL-chol) and apolipoprotein-B (APO-B)] and a strong loss of fat in legs and arms (lipoatrophy). All endothelial markers evaluated in our naive patients were higher as compared to control group. sVCAM-1 in HIV+ under therapy without lipodystrophy syndrome showed significantly decreased levels as compared to naive group (487 vs. 666 ng/ml) and vWF and sTM tended to diminish although they did not show a significant difference (130% vs. 170%, 41 vs. 45 ng/ml, respectively). Lipodystrophic patients showed a tendency to increased levels of endothelial activation markers (sVCAM-1: 500 ng/ml and vWF: 154%) together with significantly increased levels of an endothelial injury marker (sTM: 50 ng/ml) with respect to HIV+ under therapy without lipodystrophy syndrome. Plasma levels of sTM, as an endothelial injury marker, correlated with peripheral lipoatrophy (rho = -0.357) in lipodystrophic patients. In conclusion, despite the beneficial immunology effect of highly active antiretroviral treatment and the apparent decrease in the endothelial perturbation, the patients who develop lipodystrophy present altered endothelial markers and other risk factors, such as IR and dyslipemia, which turn them into a high atherothrombotic risk group.

Mitochondrial Proliferation, Dna Depletion and Adipocyte Differentiation in Subcutaneous Adipose Tissue of HIV-Positive Haart Recipients

Objectives

To examine the in vivo effects of highly active antiretroviral therapy (HAART) regimens on adipose tissue mitochondrial DNA (mtDNA) depletion, mitochondrial organellar proliferation, and markers of adipocyte differentiation and phenotype.

Design and methods

DNA and mRNA quantification using real-time PCR methods was performed on adipose tissue samples from 31 HIV-infected individuals, of whom 11 were treatment-naive and 20 were receiving HAART. mtDNA depletion was measured as mtDNA copies/cell, and mitochondrial proliferation by quantification of mitochondrial protein mass. Regulation of mitochondrial biogenesis was assessed by NRF-1 and mtTFA mRNA. PPAR γ, UCP2 and UCP1 mRNA expression was used to assess adipocyte differentiation and phenotype.

Results

Stavudine-based HAART recipients ( n=10) displayed significant mtDNA depletion (12.8% of control, P<0.001), mildly increased mitochondrial protein mass (2.6-fold of control, P=0.032) and decreased expression of PPARγ (53.9% of control, P=0.021), UCP2 (62.2% of control, P=0.024) and UCP3 (51.8% of control, P=0.047) mRNA compared with controls. Zidovudine-based HAART recipients ( n=7) also displayed significant mtDNA depletion (34.45% of control, P=0.031), increased mitochondrial protein mass (5.7-fold of control, P=0.009), and markedly increased UCP1 (18-fold of control, P=0.009) mRNA. Elevated UCP1 mRNA expression was found to be associated with non-stavudine (zidovudine or abacavir), protease inhibitor (PI)-containing HAART (95-fold of non-stavudine, non-PI-containing HAART, P=0.006).

Conclusion

Differential effects of stavudine and zidovudine therapy on mtDNA depletion and expression of adipocyte differentiation markers PPARγ and UCP2 were observed, consistent with increased adipose tissue toxicity associated with stavudine therapy. Increased UCP1 mRNA, a marker of brown adipose tissue phenotype, was associated with non-stavudine, PI-containing HAART, and may represent an adaptive response to the increased fatty acid flux associated with PI therapy, and may contribute to the increased resting energy expenditure reported in such patients.