Abacavir substitution for nucleoside analogs in patients with HIV lipoatrophy: a randomized trial

Pathophysiology and Clinical Management of Dyslipidemia in People Living with HIV: Sailing through Rough Seas

Infections with human immunodeficiency virus (HIV) and acquired immune deficiency syndrome (AIDS) represent one of the greatest health burdens worldwide. The complex pathophysiological pathways that link highly active antiretroviral therapy (HAART) and HIV infection per se with dyslipidemia make the management of lipid disorders and the subsequent increase in cardiovascular risk essential for the treatment of people living with HIV (PLHIV). Amongst HAART regimens, darunavir and atazanavir, tenofovir disoproxil fumarate, nevirapine, rilpivirine, and especially integrase inhibitors have demonstrated the most favorable lipid profile, emerging as sustainable options in HAART substitution. To this day, statins remain the cornerstone pharmacotherapy for dyslipidemia in PLHIV, although important drug-drug interactions with different HAART agents should be taken into account upon treatment initiation. For those intolerant or not meeting therapeutic goals, the addition of ezetimibe, PCSK9, bempedoic acid, fibrates, or fish oils should also be considered. This review summarizes the current literature on the multifactorial etiology and intricate pathophysiology of hyperlipidemia in PLHIV, with an emphasis on the role of different HAART agents, while also providing valuable insights into potential switching strategies and therapeutic options.

Metabolic Consequences of Antiretroviral Therapy

PURPOSE OF REVIEW

This review reports on published studies describing metabolic changes associated with antiretroviral therapy (ART) to treat HIV disease including a historical perspective of earlier ART agents, but with the main focus on newer ART agents currently in use.

RECENT FINDINGS

Studies from different countries around the world have shown that integrase inhibitor (INSTI)-based regimens as well as tenofovir alafenamide (TAF) are associated with weight gain, with women and people of black race at especially high risk. Some studies preliminarily suggest worsened metabolic outcomes associated with this weight gain including adverse effects on glucose homeostasis. Antiretroviral therapy can affect weight, adipose tissue, glucose, and lipids. As obesity is prevalent and increasing among people with HIV, awareness of risk factors for weight gain, including the ART medications associated with greater weight gain, are needed in order to inform prevention efforts. Further research is needed to better understand the long-term health consequences of INSTI- and TAF-associated weight increases.

Antiretroviral Therapy-Associated Metabolic Complications: Review of the Recent Studies

The extensive utilization of antiretroviral therapy (ART) has successfully improved human immunodeficiency virus (HIV)-associated complications. The incidence of opportunistic infections is decreased by the viral load suppression and the CD4 count promotion. However, metabolic complications, commonly bone demineralization, lipodystrophy, and lactic acidosis, are arising following the adaptation of long-term ART. The events are not drug-specific, but the severity and incidence individually vary depending upon classes of drugs. Such concerning occurrences may lead to discontinuation of current therapy or switching to another regimen with fewer adverse effects. The purpose of this review is to demonstrate the common metabolic abnormalities associated with each class of widely used ART in people living with HIV (PLHIV). Electronic databases such as PubMed, ScienceDirect, Scopus, Google Scholar, SciFinder, and Web of Science were used for the literature search. A better understanding of ART-associated metabolic adverse effects is helpful in various clinical settings so that therapists may optimize treatments in this population.

Prior exposure to thymidine analogs and didanosine is associated with long-lasting alterations in adipose tissue distribution and cardiovascular risk factors

BACKGROUND

Thymidine analogs and didanosine (ddI) have been associated with redistribution of body fat from subcutaneous adipose tissue (SAT) to visceral adipose tissue (VAT), which, in turn, is a risk factor for cardiovascular disease. We explored differences in adipose tissue distribution between people living with HIV (PLWH) with prior exposure to thymidine analogs and/or ddI, without exposure, and uninfected controls and the association with cardiovascular disease risk factors.

METHODS

In all, 761 PLWH from the Copenhagen Comorbidity in HIV Infection study, and 2283 age and sex-matched uninfected controls from the Copenhagen General Population Study were included. PLWH were stratified according to prior exposure to thymidine analogs and/or ddI. VAT and SAT were determined by abdominal computed tomography scan. Hypotheses were tested using regression analyses.

RESULTS

Exposure to thymidine analogs and/or ddI was associated with 21.6 cm larger VAT (13.8-29.3) compared to HIV infection without exposure. HIV-negative status was associated with similar VAT compared to HIV infection without exposure. Cumulative exposure to thymidine analogs and/or ddI [3.7 cm per year (2.3-5.1)], but not time since discontinuation [-1.1 cm per year (-3.4 to 1.1)], was associated with VAT. Prior exposure to thymidine analogs and/or ddI was associated with excess risk of hypertension [adjusted odds ratio (aOR) 1.62 (1.13-2.31)], hypercholesterolemia [aOR 1.49 (1.06-2.11)], and low high-density lipoprotein [aOR 1.40 (0.99-1.99)].

CONCLUSIONS

This study suggests a potentially irreversible and harmful association of thymidine analogs and ddI with VAT accumulation, which appears be involved in the increased risk of hypertension, hypercholesterolemia, and low high-density lipoprotein found in PLWH with prior exposure to thymidine analogs and/or ddI, even years after treatment discontinuation.

Lipoatrophy/lipohypertrophy outcomes after antiretroviral therapy switch in children in the UK/Ireland

BACKGROUND

Following widespread use of stavudine, a thymidine analogue, in antiretroviral therapy (ART) over the past three decades, up to a third of children developed lipoatrophy (LA) and/or lipohypertrophy (LH). Following phasing-out of stavudine, incidence of newly-diagnosed LA and LH declined dramatically. However, the natural history of existing cases should be explored, particularly with prolonged protease inhibitor exposure.

METHODS

The Collaborative HIV Paediatric Study (CHIPS) is a multicentre cohort study of most HIV-infected children in the United Kingdom and Ireland. Those on ART with a LA/LH assessment recorded in 2003-2011 were included. Assessments were completed annually by consultant physicians. Using the 0-3 grading system, LA or LH was defined as grade 2 or 3. Resolution was defined as return to grade 1 or 0 in all body regions.

RESULTS

Of 1345 children followed for median (IQR) 5.5 (2.9, 8.2) years after ART initiation, 30 developed LA and 27 developed LH, all at least 2 years after ART initiation. Median age at LA diagnosis was 11 (10, 13) years and at LH diagnosis was 13 (11, 15) years. Children with LA were more likely white (p<0.0001); lower height-for-age z-score at ART initiation (p = 0.02); initiated ART earlier (p = 0.04), with longer ART exposure (p = 0.04). Children with LH were similar to those without. Analysis of individual drugs revealed that LA was associated with greater duration of exposure to stavudine and didanosine; while LH was associated with greater duration of exposure to stavudine and ritonavir (given alone or in combination with another protease inhibitor). Median time in follow-up following ART switch was 2.8 (1.9, 4.9) and 2.5 (1.6, 4.7) years respectively. Resolution occurred in 10 (30%) of LA cases (median time to resolution 2.3 [1.8, 3.6] years) and 3 (11%) of LH cases (median time to resolution 2.0 [1.7, 2.1] years).

CONCLUSIONS

Prevalence of LA and LH were low, with some resolution noted, especially for LA. More long-term data are needed.

Adipose Tissue in HIV Infection

HIV infection and antiretroviral therapy (ART) treatment exert diverse effects on adipocytes and stromal-vascular fraction cells, leading to changes in adipose tissue quantity, distribution, and energy storage. A HIV-associated lipodystrophic condition was recognized early in the epidemic, characterized by clinically apparent changes in subcutaneous, visceral, and dorsocervical adipose depots. Underlying these changes is altered adipose tissue morphology and expression of genes central to adipocyte maturation, regulation, metabolism, and cytokine signaling. HIV viral proteins persist in circulation and locally within adipose tissue despite suppression of plasma viremia on ART, and exposure to these proteins impairs preadipocyte maturation and reduces adipocyte expression of peroxisome proliferator-activated receptor gamma (PPAR-γ) and other genes involved in cell regulation. Several early nucleoside reverse transcriptase inhibitor and protease inhibitor antiretroviral drugs demonstrated substantial adipocyte toxicity, including reduced mitochondrial DNA content and respiratory chain enzymes, reduced PPAR-γ and other regulatory gene expression, and increased proinflammatory cytokine production. Newer-generation agents, such as integrase inhibitors, appear to have fewer adverse effects. HIV infection also alters the balance of CD4+ and CD8+ T cells in adipose tissue, with effects on macrophage activation and local inflammation, while the presence of latently infected CD4+ T cells in adipose tissue may constitute a protected viral reservoir. This review provides a synthesis of the literature on how HIV virus, ART treatment, and host characteristics interact to affect adipose tissue distribution, immunology, and contribution to metabolic health, and adipocyte maturation, cellular regulation, and energy storage. © 2017 American Physiological Society. Compr Physiol 7:1339-1357, 2017.

Reversible diabetes mellitus induced by use of, and improved after discontinuation of, the antiretroviral medication zidovudine: a case report

BACKGROUND

With the advent of effective antiretroviral therapy, the care of patients with human immunodeficiency virus infection became more like that of other chronic diseases. Diabetes mellitus can also occur as one of the chronic illnesses affecting patients with human immunodeficiency virus infection. We report a case of newly developed diabetes mellitus in a patient with human immunodeficiency virus infection, most likely caused by the nucleoside analogue zidovudine, and its improvement after discontinuation of zidovudine.

CASE PRESENTATION

A Chinese man in his 30s visited our outpatient clinic for routine follow-up of human immunodeficiency virus infection. Blood tests showed hyperglycemia with a glucose level of 31.8 mmol/L and hemoglobin A1c of 8.5%. He was diagnosed with diabetes mellitus and treated with oral diabetic medications. The use of zidovudine was suspected as the cause of his diabetes, and it was replaced by other antiretroviral medication. His hyperglycemia improved, and he now no longer requires diabetic medications.

CONCLUSIONS

Diabetes mellitus can develop with the use of antiretroviral medications, but its occurrence associated with use of zidovudine is quite rare. Healthcare personnel should be aware of this rare, yet important, side effect.

Obesity in patients with HIV infection: epidemiology, consequences and treatment options

Even though wasting used to characterize patients with HIV infection prior to the antiretroviral therapy (ART) era, obesity is becoming increasingly prevalent in this population. Areas covered: In the present review, we discuss the epidemiology, consequences and treatment options for obesity in patients with HIV infection. Expert commentary: Obesity exerts a multitude of detrimental cardiometabolic effects and appears to contribute to the increasing cardiovascular mortality of this population. However, there are very limited data on the optimal management of obesity in patients with HIV infection. Given the potential for interactions between antiobesity agents and ART that might compromise viral control, lifestyle changes should represent the cornerstone for the prevention and management of obesity in HIV infection.

Switching antiretroviral regimes for the treatment of HIV: safety implications

INTRODUCTION

There are multiple reasons to switch from a virologically successful antiretroviral regimen. Some of them are related to toxicity. Lately, combination antiretroviral treatment (cART) switches have often been related to drug-drug interactions which may also eventually entail safety issues as well.

AREAS COVERED

The purpose of this review is to analyze causes of switching between virologically successful cART regimes related to safety issues. The most relevant papers were selected and summarized.

EXPERT OPINION

Switching cART has been a popular strategy to address safety issues throughout the antiretroviral era. The myriad of switching studies have paralleled the study and release into clinical practice of new antiretroviral drugs with different and often improved safety profiles. Most of them have been successful in improving antiretroviral toxicity while keeping HIV replication under control. However, it should be taken into account that, whenever a new drug is given, there is a possibility of new drug-related toxicity. Notwithstanding that, an increase in cART switching is foreseen, given the fact that we have a wide antiretroviral drug armamentarium and that people living with HIV are ageing and thus more prone to developing age-related co-morbidities whose therapies may entail new interactions and eventually new toxicities.

Adverse Effects Associated With Antiretroviral Therapy and Potential Management Strategies

A variety of adverse drug reactions (ADRs) affecting many organ systems may be observed with antiretroviral therapy (ARV), and they can be differentiated into short- and long- term effects, class effects, or individual drug effects. Commonly seen ADRs include dermatological reactions, associated with nonnucleoside reverse transcriptase inhibitors (NNRTIs) and some protease inhibitors (PIs), and gastrointestinal problems, a major side effect of PIs and of some nucleoside reverse transcriptase inhibitors (NRTIs). Metabolic complications are frequently reported in HIV-infected patients on ARV and often coexist. Lipodystrophy, hyperinsulinemia/hyperglycemia, and bone disorders (osteoporosis, osteonecrosis) are mainly associated with PIs, while lactic acidemia/acidosis are primarily a problem of NRTIs. Hyperlipidemia may be caused by almost all PIs, few NRTIs, and NNRTIs. All antiretroviral drug classes may cause both asymptomatic and symptomatic hepatotoxicity, although nevirapine is the agent most implicated in hepatic events. More drug-specific ADRs include nephrotoxicity (indinavir and tenofovir), central nervous system problems (efavirenz), hematological disturbances (zidovudine), and hypersensitivity reactions (abacavir). Anticipation of ADRs may influence a patient’s decision to delay ARV or to choose specific and potentially less active agents. Occurrence of ADRs may significantly impact a patient’s quality of life and drug adherence. Pharmacists counseling HIV-infected patients should be aware of common ADRs with ARV and potential management strategies.

Regional Body Fat Distribution in HIV-Infected Patients with Lipodystrophy

BACKGROUND

Objective criteria for the assessment of patients with lipodystrophy syndrome in human immunodeficiency virus infection (LDHIV) have not emerged.

METHODS

We compared regional body fat changes in 13 men with severe LDHIV on protease inhibitor-inclusive antiretroviral therapy with 13 control HIV-infected men using anthropometry, dual-energy X-ray absorptiometry (DEXA), and whole-body magnetic resonance imaging (MRI).

RESULTS

LDHIV patients, compared with control subjects, had thinner gluteal, suprailiac, and triceps skinfolds (p < .01) and increased waist circumference (98 +/- 5 cm vs 86 +/- 9 cm, respectively; p = .0008). DEXA studies revealed reduced lower extremity fat (12 +/- 5% vs 22 +/- 9%; p = .0006), increased head and neck fat (18 +/- 3% vs 16 +/- 1%; p = .01), and increased proportion of total body fat in the trunk (65 +/- 7% vs 53 +/- 8%; p = .0005). MRI analysis revealed reduced thigh fat (12 +/- 5% vs 22 +/- 12%; p = .01), increased dorsocervical fat depth (47 +/- 24 mm vs 19 +/- 7 mm; p = .0009), and nearly significant increase in intra-abdominal fat (218 +/- 90 cm2 vs 157 +/- 70 cm2; p = .057). Interestingly, control subjects showed a positive relationship between intra-abdominal and dorsocervical fat (r= .57, p = .04), but the LDHIV patients showed a negative relationship (r= -.55, p = .05), suggesting a novel split phenotype among LDHIV patients of either dorsocervical or intra-abdominal fat accumulation.

CONCLUSIONS

We conclude that MRI provides the best tools for definition of LDHIV syndrome and reveals variable phenotypes among LDHIV patients.

Update on HIV Lipodystrophy

When prescribed appropriately and taken adherently, antiretroviral therapy can consistently and durably suppress HIV replication, potentially translating into years of near normal health for HIV-infected persons. However, presently available antiretrovirals are associated with a cluster of physical and metabolic symptoms termed HIV lipodystrophy. This article reviews the state of knowledge about the pathogenesis and treatment of the various manifestations of these adverse effects.

Changes in Body Fat Measured by DEXA in Patients Taking Different Formulations of Stavudine

BACKGROUND

Lipoatrophy is a frequent complication of chronic stavudine therapy. Stavudine extended release formulation (stavudine ER) gives lower peak and higher trough levels than the immediate release formulation (stavudine IR), and we hypothesized that the lower peak might result in less lipoatrophy.

OBJECTIVE

To compare the rate of peripheral lipoatrophy between patients taking stavudine ER and stavudine IR.

METHOD

Body composition was measured by dual energy X-ray absorptiometry (DEXA) every 6 months for 18 months in 29 patients taking either stavudine ER or IR as part of a randomized controlled clinical trial.

RESULTS

DEXA fat measurements did not differ between the ER and IR groups at baseline, after a median of 32 months on stavudine-containing treatment. Over the 18 months of follow-up in the whole cohort limb fat decreased by a mean of 0.29 +/- 0.50 kg (p = .01) and leg fat percent decreased by a mean of 1.23% +/- 1.92% (p = .001), whereas trunk fat and trunk-to-limb fat percent ratio did not change significantly. There was no significant difference between the ER and IR groups in the rate of change of any of the fat parameters. At study completion, the proportion of patients with clinical lipodystrophy was similar in the stavudine ER and stavudine IR groups (67% and 64%, respectively; p = .893).

CONCLUSION

Stavudine ER does not appear to cause less peripheral lipoatrophy.

Switching from zidovudine/lamivudine to tenofovir/emtricitabine improves fat distribution as measured by fat mass ratio

OBJECTIVES

Fat mass ratio (FMR) has been suggested as an objective indicator of abnormal body fat distribution in HIV infection. Although it could provide more comprehensive information on body fat changes than limb fat mass, FMR has scarcely been used in clinical trials examining body fat distribution in HIV-infected patients.

METHODS

A subanalysis of a controlled, randomized clinical trial in virologically suppressed HIV-1-infected men switching from zidovudine (ZDV)/lamivudine (3TC) to emtricitabine (FTC)/tenofovir (TDF) versus continuing on ZDV/3TC was carried out. FMR was assessed by dual X-ray absorptiometry (DEXA) for a period of 72 weeks. Lipoatrophy was defined as FMR ≥ 1.5. Multivariate linear regression models for the change in FMR from baseline were fitted.

RESULTS

Sixty-five men were randomized and treated (28 in the FTC/TDF arm and 37 in the ZDV/3TC arm), and 57 completed the study (25 and 32 in each arm, respectively). In the FTC/TDF arm, adjusted mean FMR decreased by 0.52 at week 72 (P = 0.014), and in the ZDV/3TC arm it increased by 0.13 (P = 0.491; P between arms = 0.023). Among subjects with lipoatrophy (baseline FMR ≥ 1.5), adjusted FMR decreased by 0.76 (P = 0.003) in the FTC/TDF arm and increased by 0.21 (P = 0.411; P between arms = 0.009) in the ZDV/3TC arm. Baseline FMR and treatment group were significant predictors (P < 0.05) of post-baseline changes in FMR.

CONCLUSIONS

Switching from ZDV/3TC to FTC/TDF led to an improvement in FMR, compared with progressive worsening of FMR in subjects receiving ZDV/3TC, showing that fat mass not only increased but was also distributed in a healthier way after the switch.

HIV and metabolic, body, and bone disorders: what we know from low- and middle-income countries

Globally, the HIV epidemic is evolving. Life expectancy for HIV-infected individuals has been extended because of more effective and more widely available antiretroviral therapy. As a result, chronic noncommunicable diseases (NCDs) have become important comorbid conditions. In particular, HIV-infected persons are increasingly at risk of developing metabolic (diabetes, dyslipidemias), body composition (lipodystrophy, overweight/obesity) and bone mineral density abnormalities. We have summarized the published epidemiological and clinical literature regarding these HIV-NCD comorbidities in low- and middle-income countries (LMICs). We found important gaps in knowledge. Specifically, there are few studies that use standardized methods and metrics; consequently, prevalence or incidence data are not comparable. There are very little or no data regarding the effectiveness or cost-effectiveness of clinical monitoring or therapeutic interventions for metabolic disorders in HIV-infected individuals. Also, although NCDs continue to grow in the HIV-negative population of most LMICs, there are few data comparing the incidence of NCD comorbidities between HIV-infected and HIV-negative populations. To address these gaps, we describe potential research and capacity development priorities for the future.

HIV-associated lipodystrophy: a review from a Brazilian perspective

The prognosis of human immunodeficiency virus (HIV)-infected individuals has dramatically improved worldwide since the introduction of highly antiretroviral therapy. Nevertheless, along with the decrease in mortality, several body modifications not initially related to HIV infection have been reported. Disorders in lipid and glucose metabolism, accompanied by body shape abnormalities and alterations in fat distribution, began to be described. A syndrome, named "HIV-associated lipodystrophy syndrome", was coined to classify these clinical spectrum aspects. This syndrome involves not only metabolic alterations but also fat redistribution, with lipoatrophy due to subcutaneous fat loss (predominantly in the face and lower limbs) and lipohypertrophy related to central fat gain. These changes in body shape are very important to be recognized, as they are associated with worse morbidity and mortality. Self-esteem difficulties related to body alterations might lead to treatment failures due to medication adherence problems. Moreover, these alterations have been associated with an increased risk of cardiovascular events. Therefore, it is extremely important to identify this syndrome early in order to provide an even better quality of life for this population, as the clinical approach is not easy. Treatment change, medications to treat dyslipidemia, and surgical intervention are instruments to be used to try to correct these abnormalities. The aim of this study is to review clinical presentation, diagnosis, and management of body shape and metabolic complications of HIV infection from a Brazilian perspective, a medium income country with a large number of patients on antiretroviral therapy.

An update on the pharmacological strategies in the treatment of HIV-1-associated adipose redistribution syndromes

INTRODUCTION

With the introduction of combination antiretroviral therapy (ART) for HIV infection in the mid-1990s, descriptions of morphological changes and metabolic disturbances in treated patients began to emerge. HIV-1/highly active ART-associated lipodystrophy syndrome (HALS) involves metabolic abnormalities and diverse forms of anomalous fat distribution. The current review focuses on the pathophysiological basis and the clinical evidence for the use of several medical strategies in the management of HALS.

AREAS COVERED

We have covered the most relevant studies related to the pharmacological strategies in the treatment of HALS, with attention to the current and novel antiretroviral agents.

EXPERT OPINION

The most commonly used strategies for HALS reversion have included modification of host-dependent factors, including those related to HIV-1 infection and those associated with ART. Preventive and medical strategies have been associated with moderate success. The only intervention that offers an immediate aesthetical improvement for patients with HALS so far has been plastic surgery.

Treatment-limiting toxicities associated withnucleoside analogue reverse transcriptase inhibitor therapy: A prospective, observational study

BACKGROUND

The Recover Study is an ongoing, prospective study designed 10 to assess toxicity associated with the use of nucleoside analogue reverse transcriptase inhibitors (NRTIs) (stavudine, zidovudine, lamivudine, didanosine, abacavir) in HIV-1-infected patients receiving highly active antiretroviral therapy (HAART) in routine clinical practice. This project is being conducted at 120 HIV units at teaching hospitals across Spain.

OBJECTIVE

The aim of this study was to identify the most common treatment-limiting 10 moderate to severe clinical and laboratory adverse effects (AEs), and the individual NRTIs involved in the development of these effects, in HIV-1-infected patients receiving HAART who discontinued use of an NRTI in the Recover Study.

METHODS

Patients eligible for participation in the Recover Study are aged10 ≥18 years; have virologically documented HIV-1 infection; have sustained viral suppression (viral load <200 cells/mL or stable, heavily experienced [ie, have received ≥3 antiretroviral regimens] patients with viral load <5000 cells/mL) for ≥6 months; are receiving HAART; are undergoing active follow-up; and have developed 2:1 NRTI-associated AE that, in the opinion of a study investigator and under the conditions of routine clinical practice, justified discontinuation of treatment with the offending drug (principal AE/offending NRTI). The present study included patients recruited for the Recover Study between September 2002 and May 2003.

RESULTS

A total of 1391 patients were enrolled (966 men, 425 women; mean 1 age, 42 years [range, 18-67 years]). Five hundred six patients (36.4%) had been diagnosed with AIDS. The mean duration of treatment with the offending NRTI was 74 months (range, 6-156 months). Seven hundred nine patients (51.0%) were receiving fourth-line (or more) therapy. Eight hundred twenty-one patients (59.0%) were receiving nonnucleoside analogues, and 552 patients (39.7%), protease inhibitors, as components of their HAART regimens. The NRTIs with the highest discontinuation rates were stavudine (914 patients [65.7%]) and zidovudine (177 [12.7%]). The most frequent NRTI-related AEs were lipoatrophy (550 patients [39.5%]) and peripheral neuropathy (170 [12.2%]). Lipoatrophy was most commonly associated with stavudine (480/550 cases [87.3%]); periph eral neuropathy, with stavudine and didanosine (107/170 [62.9%] and 48/170 [28.2%] cases, respectively); and anemia, with zidovudine (70/77 cases [90.9%]).

CONCLUSIONS

The results of this study in patients with HIV-1 recruited in the10 Recover Study and undergoing HAART suggest that long-term treatment with NRTIs is associated with AEs (lipoatrophy, peripheral neuropathy, and lipodystrophy), with morphologic disorders (lipoatrophy, lipodystrophy) being the most common AEs leading to discontinuation. Minimizing these AEs by switching to an NRTI not associated with these AEs (eg, tenofovir) would contribute to adherence and hence efficacy of long-term HAART.

Effects of switching from stavudine to raltegravir on subcutaneous adipose tissue in HIV-infected patients with HIV/HAART-associated lipodystrophy syndrome (HALS). A clinical and molecular study

HIV-1/HAART-associated lipodystrophy syndrome (HALS) has been associated with exposure to stavudine (d4T) through mitochondrial dysfunction. We performed a 48-week study to assess the effects of switching from d4T to raltegravir (RAL) on metabolic and fat molecular parameters of patients with HALS. Forty-two patients with HALS and a median exposure to d4T > 7 years were switched to RAL and followed for 48 weeks. Fasting metabolic tests, HIV RNA, CD4 cell count, and fat measured by DEXA were obtained at baseline and week 48. mtDNA and gene transcripts for PPAR gamma, adiponectin, cytochrome b, Cox IV, TNF alpha, MCP-1 and CD68 were assessed in paired subcutaneous fat tissue biopsies. Lipid parameters, fasting glucose, insulin, and HOMA-IR did not change significantly. Whole body fat (P = 0.0027) and limb fat mass (P<0.0001) increased from baseline. Trunk/limb fat ratio (P = 0.0022), fat mass ratio (P = 0.0020), fat mass index (P = 0.0011) and percent leg fat normalized to BMI (P<0.0001) improved after 48 weeks. Relative abundance of mtDNA, expression of PPAR gamma, adiponectin, Cyt b, and MCP-1 genes increased, whereas Cox IV, TNF alpha, and CD68 did not change significantly from baseline. Switching from d4T to RAL in patients with HALS is associated with an increase in limb fat mass and an improvement in markers of adipocyte differentiation and mitochondrial function in SAT.

Fixed dose combination abacavir/lamivudine in the treatment of HIV-1 infection

The fixed dose combination of abacavir with lamivudine represents a new treatment option for patients infected with HIV. Fixed dose combination abacavir/lamivudine has the convenience of one pill and once-daily dosing. It achieves comparable suppression of plasma HIV RNA with the pill's individual components dosed twice daily and with thymidine analogs combined with lamivudine. The combination is well tolerated, with the potential advantages of less lipoatrophy and fewer metabolic perturbations. However, the abacavir component may cause hypersensitivity reactions, which are reported in up to 8% of patients, and are potentially life threatening. Fixed dose combination abacavir/lamivudine should be considered as a viable treatment option for HIV-infected patients, particularly for those who have otherwise limited nucleoside reverse transcriptase inhibitor choices.

Small-dense LDL cholesterol/large-buoyant LDL cholesterol ratio as an excellent marker for indicating lipodystrophy in HIV-infected patients

OBJECTIVES

To examine whether the lipid parameters are predicting factors for human immunodeficiency virus (HIV)-associated lipodystrophy.

METHODS

Whole-body fat compositions of HIV-positive patients receiving stavudine-containing antiretroviral regimens (n = 79) were determined. Lipodystrophy was defined as a ratio of trunk fat mass/lower limb fat mass greater than 2.28. Blood samples were analyzed for total cholesterol (TC), triglycerides, low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), small-dense LDL-C (sdLDL-C), apoAI, apoB, lipoprotein(a), and CD4 cell counts. Large-buoyant LDL-C (lbLDL-C) was calculated (LDL-C minus sdLDL-C).

RESULTS

Twenty-six patients were classified as having lipodystrophy. The mean values of triglycerides, HDL-C, sdLDL-C, apoB, TC/HDL-C, apolipoprotein (apo) B/apoAI, and sdLDL-C/lbLDL-C showed significant differences between patients with and without lipodystrophy (P < .02). Using logistic regression analysis, sdLDL-C/lbLDL-C was identified as a significant predictor of lipodystrophy (P < .001). At a ratio of 0.554, the odds ratio was 17.8 with a likelihood ratio of 5.5.

CONCLUSIONS

The sdLDL-C/lbLDL-C ratio is an excellent marker for indicating lipodystrophy in HIV-infected patients.

The Official Positions of the International Society for Clinical Densitometry: Indications of Use and Reporting of DXA for Body Composition

The technique of body composition by dual-energy X-ray absorptiometry (DXA) has been used for several years in the research environment. Its ability to accurately and precisely measure lean, fat, and mineral composition in various body compartments has been well validated. Furthermore, the technique is widely available to clinical patients on existing DXA instruments throughout the world through the use of specific software packages and scanning algorithms. There have been few clear statements regarding the clinical indications for body composition measurement in patients outside the research setting. This is in part because of the lack of specific documented interventions that would be affected by body composition test results, beyond usual clinical advice. We have examined a few of the most common, specific scenarios (HIV therapy, sarcopenia, bariatric surgery, obesity) and proposed indications for body composition assessment. We have also discussed contraindications to body composition testing.

Long-term body composition and metabolic changes in HIV-infected children switched from stavudine to tenofovir and from protease inhibitors to efavirenz

This is an 8-year cohort study of 24 HIV-infected patients aged 5-17 years to assess body composition and metabolic changes after switching from lamivudine + stavudine (d4T) + protease inhibitors (PI) to lamivudine + tenofovir (TDF) + efavirenz (EFV). Body composition (dual-energy X-ray absorptiometry) and cholesterol, high-density lipoprotein (HDL) cholesterol, low-density lipoprotein (LDL) cholesterol, triglycerides, glucose and insulin were measured annually. Linear mixed models and generalized linear mixed models were used to evaluate time changes of the outcome of interest. Body mass index increased linearly by 0.3 kg/m(2)/year (p < 0.001); waist circumference increased non-linearly from 68 to 74 cm (p = 0.004 for the linear term and p = 0.04 for the quadratic term). Percent body fat, percent trunk fat and percent bone mineral content increased linearly by 0.6%/year (p = 0.005), 1.2%/year (p < 0.001) and 0.02%/year (p = 0.04), respectively. Percent arm fat remained stable (p = 0.5), and percent leg fat decreased linearly by 1.2%/year (p < 0.001). The probability of low HDL was 0.2% at baseline and remained stable during the study. The probability of high triglycerides was 3% at baseline and increased linearly to become 11% at the 8th year of follow-up (p = ns). The probability of high glucose was 1% for the whole study duration.

CONCLUSIONS

patients, after switching from d4T to TDF and from PI to EFV, show most of the changes in anthropometry and body composition associated with normal growth and no frankly pathological change in metabolic parameters.

Pathophysiology of GHRH-growth hormone-IGF1 axis in HIV/AIDS

Aberrations in GHRH-GH -IGF-I axis are common in the complex of HIV, HAART and AIDS. There are 2 distinct mechanisms at play in HIV and AIDS. One is primarly associated with development of lipodystrophy and results in complications such as chronic inflammation, insulin resistance, lipid and metabolic abnormalities. HIV lipodystrophy is found especially in those on highly active anti-retroviral therapy (HAART). The various processes involved in lipodystrophy result in the suppression of pituitary GH production. The mechanism of low GH levels relates to increased somatostatin tone, decreased Ghrelin, increased free fatty acids (FFA) and insulin resistance. On the other hand in AIDS wasting syndrome; elevated GH and low IGF-1 levels are seen suggesting GH resistance. The GHRH analog-Tesamorelin is the only treatment option, which is FDA approved for use in reduction of excess abdominal fat in patients with HIV-associated lipodystrophy. Although long-term clinical trials and experience is needed to further study the benefits and risks of Tesamorelin.

Biceps skin-fold thickness may detect and predict early lipoatrophy in HIV-infected children

BACKGROUND

The prevalence of potentially stigmatizing lipoatrophy in children receiving antiretroviral therapy in Southern Africa is high, affecting around a third of children. Early diagnosis of lipoatrophy is essential for effective intervention to arrest progression.

METHODS

Prepubertal children receiving antiretroviral therapy were recruited from a hospital-based family HIV clinic in Cape Town and followed up prospectively. Lipoatrophy was identified and graded by consensus between 2 HIV pediatricians. A dietician performed anthropometric measurements of trunk and limb fat. Anthropometric measurements in children with and without lipoatrophy were compared using multivariable linear regression adjusting for age and gender. The most discerning anthropometric indicators of lipoatrophy underwent receiver operating characteristic curve analysis. The precision of anthropometric measurements performed by an inexperienced healthcare worker was compared with that of a research dietician.

RESULTS

Of 100 recruits, 36 had lipoatrophy at baseline and a further 9 developed lipoatrophy by 15-month follow-up. Annual incidence of lipoatrophy was 12% (confidence interval [CI]: 5-20%) per person-year of follow-up. A biceps skin-fold thickness <5 mm at baseline had a sensitivity of 89% (CI: 67-100%) and a specificity of 60% (CI: 46-75%) for predicting development of lipoatrophy by 15-month follow-up. Negative and positive predictive values were 97% (CI: 91-100%) and 32% (CI: 14-50%).

CONCLUSION

Biceps skin-fold thickness <5 mm in prepubertal children exposed to thymidine analogue-based antiretroviral therapy may be a useful screening tool to identify children who are likely to develop lipoatrophy. The variation in precision of measurements performed by an inexperienced healthcare worker only marginally impacted performance.

Systematic review of antiretroviral-associated lipodystrophy: lipoatrophy, but not central fat gain, is an antiretroviral adverse drug reaction

Background

Lipoatrophy and/or central fat gain are observed frequently in patients on antiretroviral therapy (ART). Both are assumed to be antiretroviral adverse drug reactions.

Methods

We conducted a systematic review to determine whether fat loss or gain was more common in HIV-infected patients on ART than in uninfected controls; was associated with specific antiretrovirals; and would reverse after switching antiretrovirals.

Results

Twenty-seven studies met our inclusion criteria. One cohort study reported more lipoatrophy, less subcutaneous fat gain, but no difference in central fat gain in HIV-infected patients on ART than in controls. Randomised controlled trials (RCTs) showed more limb fat loss (or less fat gain) with the following regimens: stavudine (versus other nucleoside reverse transcriptase inhibitors (NRTIs)); efavirenz (versus protease inhibitors (PIs)); and NRTI-containing (versus NRTI-sparing). RCTs showed increased subcutaneous fat after switching to NRTI-sparing regimens or from stavudine/zidovudine to abacavir/tenofovir. There were no significant between-group differences in trunk and/or visceral fat gain in RCTs of various regimens, but results from efavirenz versus PI regimens were inconsistent. There was no significant between-group differences in central fat gain in RCTs switched to NRTI-sparing regimens, or from PI-containing regimens.

Conclusions

There is clear evidence of a causal relationship between NRTIs (especially thymidine analogues) and lipoatrophy, with concomitant PIs possibly having an ameliorating effect or efavirenz causing additive toxicity. By contrast, central fat gain appears to be a consequence of treating HIV infection, because it is not different from controls, is not linked to any antiretroviral class, and doesn't improve on switching.

Recovery from lipodystrophy in HIV-infected children after substitution of stavudine with zidovudine in a non-nucleoside reverse transcriptase inhibitor-based antiretroviral therapy

BACKGROUND

Substitution of stavudine with zidovudine may lead to recovery from lipodystrophy (LD) in HIV-infected children.

METHODS

We prospectively followed HIV-infected children enrolled in an earlier LD study conducted between 2002 and 2004 at Chiang Mai University Hospital in northern Thailand. In 2006, stavudine was substituted with zidovudine. All children were evaluated by a clinical LD checklist modified from that of the European Pediatric LD study group together with waist/hip measurement at baseline and 24, 48, 72, and 96 weeks after substitution. The waist-to-hip ratios were converted to age- and sex-adjusted z scores based on normal ranges in healthy Thai children.

RESULTS

Forty-five lipodystrophic children with 36 episodes of lipohypertrophy and 22 episodes of lipoatrophy were enrolled. By weeks 48 and 96 after substitution, 40% and 47% of lipohypertrophy resolved, whereas 59% and 73% of lipoatrophy resolved, respectively. The rate of resolution of lipoatrophy was higher than that of lipohypertrophy at 48 weeks after substitution and thereafter. Ninety-six weeks after changing to zidovudine therapy, 8 children still had LD (1 with both lipoatrophy and lipohypertrophy, 7 with lipohypertrophy). No clinically significant hematologic adverse event was observed.

CONCLUSIONS

Substitution of stavudine with zidovudine resulted in decreased severity or resolution of LD among HIV-infected children and adolescents.

A randomized comparative 96-week trial of boosted atazanavir versus continued boosted protease inhibitor in HIV-1 patients with abdominal adiposity

BACKGROUND

Abdominal adiposity in HIV-1 patients initiating antiretroviral therapy may be part of a restoration-to-health phenomenon. Lipoatrophy is associated with long-term thymidine analogue therapy. Individual protease inhibitors (PIs) differ in their effects on lipids and insulin resistance.

METHODS

A randomized open-label multicentre 96-week trial compared changes in fat distribution in patients with suppressed HIV-1 RNA and abdominal adiposity, who either continued on their current twice-daily ritonavir-boosted PI (PI/r) or switched to once-daily boosted atazanavir (ATV/r). Treatment with two nucleoside reverse transcriptase inhibitors was unchanged. Body composition was assessed by dual-energy x-ray absorptiometry (DEXA) and abdominal computerized tomography (CT) scanning.

RESULTS

In total, 201 patients were randomized; 131 switched to ATV/r. Viral suppression (<50 copies/ml) was similarly maintained (93% ATV/r versus 89% PI/r). Mean changes from baseline in trunk-to-limb fat ratio were similar; difference estimates 0.03 (95% CI -0.06, 0.12; P=0.48 at week 48) and 0.02 (95% CI -0.10, 0.14; P=0.73 at week 96). More patients in the PI/r arm had a decrease of ≥20% in limb fat from baseline at week 96. Significantly greater reductions in proatherogenic lipids occurred following switch to ATV/r. Both treatment regimens were generally well-tolerated; the incidence of grade 3-4 treatment-related clinical adverse events was 34% among ATV/r recipients versus 4% of PI/r-treated patients.

CONCLUSIONS

Switching to ATV/r had no demonstrable benefit on abdominal adiposity. Maintenance of efficacy, less limb fat loss and marked reduction in proatherogenic lipids was observed with ATV/r compared with continuing a PI/r regimen.

Polyacrylamide hydrogel injection in the management of human immunodeficiency virus-related facial lipoatrophy: results of the LIPOPHILL open-label study

Combination antiretroviral therapy (cART) can cause potentially stigmatizing facial lipoatrophy. Encouraging preliminary results have been reported with 2.5% polyacrylamide hydrogel for facial reconstruction. The aim of this multicenter, open-label noncomparative pilot study was to evaluate the efficacy and safety of intradermal facial injections of polyacrylamide hydrogel in HIV-infected patients with severe facial lipoatrophy. The patients received between two and six injections every 4 weeks, according to the aesthetic results. Clinical efficacy was evaluated by means of facial ultrasonography and photography at baseline and months 6, 12, and 24. Adverse events, patient satisfaction, and quality of life were also assessed. One hundred and eleven patients were enrolled and received at least one injection. Mean cheek skin thickness was 9.7 mm [95% CI: 9.1 to 10.2] at baseline. It rose by an average of 4.4 mm [95% CI: 3.9 to 4.9; p<0.001] at month 12 and a further 0.87 mm [95% CI: 0.52 to 1.23; p<0.001] at month 24. The Overall Treatment Satisfaction scale showed an improvement in more than 88% of patients at all visits, based on the appreciations of the patients, their close relatives and physicians, and on independent assessment of facial photographs. Quality of life improved significantly over time, as shown by the lipodystrophy-specific ABCD scale. No severe adverse effects related to the polyacrylamide hydrogel were noted. Polyacrylamide hydrogel injections were well tolerated and significantly improved the aesthetic aspect and quality of life of HIV-infected patients with facial lipoatrophy.

Changes in body composition and mitochondrial DNA in HIV-1-infected patients switching to fixed-dose abacavir/lamivudine or tenofovir/emtricitabine: a substudy of the BICOMBO trial

BACKGROUND

Fat distribution, bone mineral density (BMD) and mitochondrial DNA (mtDNA) may improve, in the long-term, after switching from nucleoside reverse transcriptase inhibitors (NRTIs) to fixed-dose abacavir (ABC)/lamivudine (3TC) or tenofovir (TDF)/emtricitabine (FTC).

METHODS

This was a prospective, randomized, open-label, multicentre substudy of the BICOMBO trial in which virologically suppressed patients had their NRTIs switched to ABC/3TC or TDF/FTC. Whole-body dual-energy X-ray absorptiometry (DXA) was used to measure limb, trunk and total body fat and total BMD. Lumbar and hip DXA scans were used to measure lumbar and hip BMD. Fat mass ratio (FMR; % trunk fat/% leg fat by whole-body DXA) was used to assess fat distribution. mtDNA was measured in peripheral blood mononuclear cells (PBMCs). Parameters of interest were measured at baseline, 48 and 96 weeks, and were compared between treatment groups.

RESULTS

Of 56 patients included, 45 (20 ABC/3TC and 25 TDF/FTC) completed the substudy. After 96 weeks, ABC/3TC (+756 g, +12.1%) and TDF/FTC (+337 g, +7.6%) led to non-significantly different increases in limb fat (P=0.60). By contrast, trunk fat showed a significant increase (P=0.04) with ABC/3TC (+1,184 g, +10.6%) relative to TDF/FTC (-370 g, -4.2%). Median (IQR) FMR remained unchanged with ABC/3TC (-0.01 [-0.16-0.06]; P=0.23), but it decreased significantly with TDF/FTC (-0.13 [-0.30-0.00]; P=0.007). Total BMD and mtDNA significantly increased after 96 weeks, without differences between groups.

CONCLUSIONS

Switching from NRTIs to either ABC/3TC or TDF/FTC led to similar increases in limb fat, BMD and PBMC mtDNA after 96 weeks.

Dysregulation of glucose metabolism in HIV patients: epidemiology, mechanisms, and management

HIV-infected patients on highly active antiretroviral therapy (HAART) have increased prevalence of a number of chronic metabolic disorders of multifactorial but unclear etiology. These include disorders of lipid metabolism with or without lipodystrophy, insulin resistance, and an increased prevalence of impaired glucose tolerance, diabetes mellitus, and cardiometabolic syndrome. While much attention has been focused on the lipid and cardiovascular disorders, few investigations have attempted to characterize the prevalence, incidence, etiology, mechanisms, and management of glycemic disorders in HIV patients. In this review, we have focused specifically on a comprehensive assessment of dysglycemia in the context of HIV infection and HAART.

Iatrogenic mitochondriopathies: a recent lesson from nucleoside/nucleotide reverse transcriptase inhibitors

The use of nucleoside/nucleotide reverse transcriptase inhibitors (NRTIs) has revolutionized the treatment of infection by human immunodeficiency virus (HIV) and hepatitis-B virus. NRTIs can suppress viral replication in the long-term, but possess significant toxicity that can seriously compromise treatment effectiveness. The major toxicity of NRTIs is mitochondrial toxicity. This manifests as serious side effects such as myopathy, peripheral neuropathy and lactic acidosis. In general, it is believed that the mitochondrial pathogenesis is closely related to the effect of NRTIs on mitochondrial DNA polymerase-γ. Depletion and mutation of mitochondrial DNA during chronic NRTI therapy may lead to cellular respiratory dysfunction and release of reactive oxidative species, resulting in cellular damage. It is now apparent that the etiology is far more complex than originally thought. It appears to involve multiple mechanisms as well as host factors such as HIV per se, inborn mitochondrial mutation, and sex. Management of mitochondrial toxicity during NRTI therapy remains a challenge. Interruption of NRTI therapy and substitution of the causative agents with alternative better-tolerated NRTIs represents the mainstay of management for mitochondrial toxicity and its clinical manifestations. A range of pharmacological approaches has been proposed as treatments and prophylaxes.

Body fat distribution in perinatally HIV-infected and HIV-exposed but uninfected children in the era of highly active antiretroviral therapy: outcomes from the Pediatric HIV/AIDS Cohort Study

BACKGROUND

Associations between abnormal body fat distribution and clinical variables are poorly understood in pediatric HIV disease.

OBJECTIVE

Our objective was to compare total body fat and its distribution in perinatally HIV-infected and HIV-exposed but uninfected (HEU) children and to evaluate associations with clinical variables.

DESIGN

In a cross-sectional analysis, children aged 7-16 y in the Pediatric HIV/AIDS Cohort Study underwent regionalized measurements of body fat via anthropometric methods and dual-energy X-ray absorptiometry. Multiple linear regression was used to evaluate body fat by HIV, with adjustment for age, Tanner stage, race, sex, and correlates of body fat in HIV-infected children. Percentage total body fat was compared with NHANES data.

RESULTS

Males accounted for 47% of the 369 HIV-infected and 51% of the 176 HEU children. Compared with HEU children, HIV-infected children were older, were more frequently non-Hispanic black, more frequently had Tanner stage ≥3, and had lower mean height (-0.32 compared with 0.29), weight (0.13 compared with 0.70), and BMI (0.33 compared with 0.63) z scores. On average, HIV-infected children had a 5% lower percentage total body fat (TotF), a 2.8% lower percentage extremity fat (EF), a 1.4% higher percentage trunk fat (TF), and a 10% higher trunk-to-extremity fat ratio (TEFR) than did the HEU children and a lower TotF compared with NHANES data. Stavudine use was associated with lower EF and higher TF and TEFR. Non-nucleotide reverse transcriptase inhibitor use was associated with higher TotF and EF and lower TEFR.

CONCLUSION

Although BMI and total body fat were significantly lower in the HIV-infected children than in the HEU children, body fat distribution in the HIV-infected children followed a pattern associated with cardiovascular disease risk and possibly related to specific antiretroviral drugs.

Growth hormone and tesamorelin in the management of HIV-associated lipodystrophy

HIV-infected patients on highly active antiretroviral therapy (HAART) develop a complex of body composition changes known, including peripheral fat loss (lipoatrophy) and central fat accumulation (lipohypertrophy). These changes may cause significant patient distress, which could in turn interfere with adherence to antiretroviral therapy. Treatment options - including antiretroviral switch, insulin sensitizers, and surgical approaches - have been associated with limited success and potential complications. The observation that low growth hormone levels are associated with central fat accumulation among HIV patients has led to the development of tesamorelin (a growth hormone releasing hormone analog) for the management of central fat accumulation. Randomized controlled trials have shown that administration of tesamorelin is safe and effective in reducing central fat accumulation among HIV-infected patients. This effect is transient, however, and its association with improved cardiovascular risk remains unclear.

Disorders of fat partitioning in treated HIV-infection

HIV-associated lipodystrophy is clinically characterized by body fat changes including subcutaneous fat loss (lipoatrophy) with or without truncal fat accumulation (lipohypertrophy). Thymidine nucleoside reverse transcriptase inhibitors, stavudine and to a lesser extent zidovudine, are major contributors for lipoatrophy. Drug factors are not clear for lipohypertrophy. Restoration to health with effective viral suppression and weight gain may be factors playing significant roles in lipohypertrophy. Mitochondrial dysfunction and inflammation in subcutaneous adipose tissue are key factors in the pathogenesis of HIV-associated lipoatrophy. The pathogenesis of lipohypertrophy is less well understood. Switching from thymidine nucleoside reverse transcriptase inhibitors restores subcutaneous fat in patients with HIV-associated lipoatrophy, but improvement is slow and limited. Surgical filling cosmetically improves facial lipoatrophy. Exercise and diet may reduce increased visceral adipose tissue. Liposuction may be useful to remove superficial, localized fat accumuli.

From old to new nucleoside reverse transcriptase inhibitors: changes in body fat composition, metabolic parameters and mitochondrial toxicity after the switch from thymidine analogs to tenofovir or abacavir

INTRODUCTION

Thymidine analogs zidovudine (AZT) and stavudine (d4T) have been widely used because of their antiviral activity against HIV, but at the expense of high toxicity, mainly related to mitochondrial damage. Many studies have been performed replacing AZT or d4T with newer nucleoside analogs reverse transcriptase inhibitors (NRTIs) with less toxicity, such as tenofovir (TDF) or abacavir (ABC), maintaining virological efficacy.

AREAS COVERED

Relevant literature was identified using a PubMed search of articles published up to June 2010. Search terms included: 'thymidine analogs', 'stavudine', 'zidovudine', 'd4T', 'AZT', 'ZDV', 'treatment switch'. Original articles in which d4T or AZT had been replaced by TDF or ABC as switch strategies (with undetectable viral load) were reviewed where information about body fat distribution, mitochondrial functionality and/or plasma lipid parameters were available. Relevant references from these articles were also considered. Only studies performed in adult patients (18 years or older) are included. The readers will gain a better understanding of the toxicity caused by thymidine analogs, the treatment alternatives and the benefits observed after treatment switch to newer NRTIs.

EXPERT OPINION

Thymidine analogs AZT and d4T yield considerable toxicity and proactive switch to newer NRTIs such as TDF or ABC is necessary in order to avoid or partially reverse such side effects.

Metabolic complications associated with antiretroviral therapy in HIV-infected and HIV-exposed uninfected paediatric patients

IMPORTANCE OF THE FIELD

HIV-infection has become a chronic disease in paediatric patients with the potential for long-term survival and exposure to antiretroviral (ARV) therapies for 2 decades longer than HIV-infected adults. On the other hand, the administration of ARV to HIV-infected pregnant women has greatly increased both treatment of HIV infection and prevention of perinatal HIV transmission. Therefore, researches aiming to evaluate the safety of ARV therapies in HIV-infected children as well as in HIV-uninfected infants born to HIV-infected mothers are emerging as a new challenge and urgent priority.

AREAS COVERED IN THIS REVIEW

The purpose of this review is to describe some of the more concerning metabolic complications associated with ARV in paediatric population: hyperlactataemia (HLA) syndromes, body shape abnormalities, disorders of glucose homeostasis and dyslipidaemia in HIV-infected children and adolescents. Frequency, risk factors, clinical findings, prevention and intervention strategies of the previously described abnormalities are discussed in depth.

WHAT THE READER WILL GAIN

This review covers our current understanding of HLA syndromes in ARV-exposed uninfected infants born to HIV-infected mothers.

TAKE HOME MESSAGE

Prevention of these metabolic complications should assume prominence and future researches should address several of the existing treatment gaps.

The MMP1 (-16071G/2G) single nucleotide polymorphism associates with the HAART-related lipodystrophic syndrome

OBJECTIVE

Matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs) are involved in extracellular matrix remodelling and adipocyte differentiation and are inhibited by antiretrovirals. MMPs and TIMPs and their single nucleotide polymorphisms (SNPs) might contribute to the HAART-related lipodystrophic syndrome pathogenesis.

DESIGN AND SETTING

Cross-sectional study in a university-based outpatient clinic.

PATIENTS AND METHODS

Two hundred and sixteen HIV-infected patients on extended HAART were studied. Serum MMPs (1, 2, 3, 8, 9, 10, 13) and TIMPs (1, 2, 4) were measured by ELISA microarrays. MMP1 (-16071G/2G) SNP was also genotyped. Lipodystrophic syndrome was diagnosed by a clinical scale validated by fat dual energy X-ray absorptiometry.

RESULTS

Eighty-two patients (38.0%) showed lipodystrophic syndrome, mostly lipoatrophy. The 2G/2G MMP1 SNP genotype was more frequent among lipodystrophic syndrome patients (41.3 vs. 20.5%, odds ratio, 2.73; 95% confidence interval, 1.41-5.29; χ² = 9.62, P = 0.002 for HIV-infected patients with and without lipodystrophic syndrome respectively). Carriers of this genotype had higher serum levels of MMP1 compared with those with the 1G/1G (P = 0.02). Higher MMP1 (P = 0.022) and lower TIMP4 (P = 0.038) serum levels were observed while comparing HIV patients with and without lipodystrophic syndrome. MMP1 2G carriage (P = 0.0008), TIMP4 lower serum levels (P = 0.02), treatment with stavudine (P < 0.0001), treatment with zidovudine (P = 0.006) and absence of hepatitis C virus coinfection (P = 0.002) were associated with lipodystrophic syndrome by logistic regression.

CONCLUSION

MMP1 SNP, which induced increased serum levels of this protein, was associated with lipodystrophic syndrome.

The efficacy and safety of insulin-sensitizing drugs in HIV-associated lipodystrophy syndrome: a meta-analysis of randomized trials

Background

HIV-associated lipodystrophy syndrome (HALS) is characterized by insulin resistance, abnormal lipid metabolism and redistribution of body fat. To date, there has been no quantitative summary of the effects of insulin sensitizing-agents for the treatment of this challenging problem.

Methods

We searched MEDLINE, the Cochrane Library, clinical trial registries, conference proceedings and references for randomized trials evaluating rosiglitazone, pioglitazone or metformin in patients with evidence of HALS (last update December 2009). Two reviewers independently abstracted data and assessed quality using a standard form. We contacted authors for missing data and calculated weighted mean differences (WMD) and 95% confidence intervals (CI) for each outcome.

Results

Sixteen trials involving 920 patients met inclusion criteria. Rosiglitazone modestly improved fasting insulin (WMD -3.67 mU/L; CI -7.03, -0.31) but worsened triglycerides (WMD 32.5 mg/dL; CI 1.93, 63.1), LDL (WMD 11.33 mg/dL; CI 1.85, 20.82) and HDL (WMD -2.91 mg/dL; CI -4.56, -1.26) when compared to placebo or no treatment in seven trials. Conversely, pioglitazone had no impact on fasting insulin, triglycerides or LDL but improved HDL (WMD 7.60 mg/dL; CI 0.20, 15.0) when compared to placebo in two trials. Neither drug favorably impacted measures of fat redistribution. Based on six trials with placebo or no treatment controls, metformin reduced fasting insulin (WMD -8.94 mU/L; CI -13.0, -4.90), triglycerides (WMD -42.87 mg/dL; CI -73.3, -12.5), body mass index (WMD -0.70 kg/m²; CI -1.09, -0.31) and waist-to-hip ratio (WMD -0.02; CI -0.03, 0.00). Three trials directly compared metformin to rosiglitazone. While effects on insulin were comparable, lipid levels and measures of fat redistribution all favored metformin. Severe adverse events were uncommon in all 16 trials.

Conclusion

Based on our meta-analysis, rosiglitazone should not be used in HALS. While pioglitazone may be safer, any benefits appear small. Metformin was the only insulin-sensitizer to demonstrate beneficial effects on all three components of HALS.

Rosiglitazone improves lipoatrophy in patients receiving thymidine-sparing regimens

OBJECTIVE

Thymidine reverse transcriptase inhibitors (tNRTI) are strong inhibitors of PPAR-gamma and clearly implicated as a cause of lipoatrophy. Thiazolidenediaones (TZD), potent PPAR-gamma agonists, would be expected to be beneficial in HIV lipoatrophy, but prior studies have been conflicting. None specifically excluded the use of tNRTIs. We report the first study in individuals treated with tNRTI-sparing regimens using a TZD for treatment of HIV lipoatrophy.

DESIGN

This double-blind, placebo-controlled study evaluated limb fat in HIV-infected individuals with lipoatrophy who discontinued tNRTI at least 24 weeks prior to enrollment.

METHODS

Individuals were randomized to rosiglitazone vs. placebo for 48 weeks. Dual energy X-ray absorptiometry (DEXA)-scans and fasting metabolic assessments were serially performed.

RESULTS

We enrolled 71 individuals, 17% were female and 51% white. Baseline characteristics were similar between groups except for higher total cholesterol in the placebo group (P = 0.04). At 48 weeks, limb fat (grams) increased significantly (P = 0.02) more in the rosiglitazone than in the placebo group: median (IQR) 448 (138, 1670) vs. 153 (-100, 682), respectively. Of lipids parameters, only total cholesterol increased significantly more in the rosiglitazone group (P = 0.008). Prevalence of metabolic syndrome and total bone mineral density did not change between or within groups.

CONCLUSION

In the absence of tNRTI, rosiglitazone significantly improves lipoatrophy without deleterious effect on bone mineral density. Total cholesterol, but not triglycerides, significantly increased in the rosiglitazone arm. The glitazones may be a promising addition for accelerating fat recovery in individuals who had switched off tNRTI and remain with significant lipoatrophy.

A meta-analysis of six placebo-controlled trials of thiazolidinedione therapy for HIV lipoatrophy

OBJECTIVE

To determine the impact of thiazolidinediones (TZD) on changes in limb fat mass in HIV-infected individuals, particularly in those not receiving a thymidine analogue.

METHODS

Individual patient data from placebo-controlled, randomized trials of rosiglitazone (n = 5) or pioglitazone (n = 1) were combined. Generalized estimating equation (GEE) models were used to estimate the treatment effect on changes in limb fat mass.

RESULTS

In the combined dataset of 427 patients, the baseline median age was 45 years, 86% were male, 80% were Caucasian, 63% were receiving stavudine (d4T) or zidovudine (AZT), 66% were on protease inhibitors, and median body mass index was 23 kg/m(2). In a univariate GEE model, TZD was associated with an increase in limb fat mass (coeff = 0.14 kg vs placebo, P = .04). In a multivariable GEE model, patients receiving pioglitazone had significantly higher limb fat mass gains (coeff = 0.35 kg, P < or = .01) compared to patients receiving placebo, while patients on rosiglitazone did not (coeff = 0.05 kg, P = .48). Interactions between thymidine analogue use and rosiglitazone and pioglitazone were not significant.

CONCLUSIONS

In this meta-analysis, pioglitazone therapy was more effective than placebo to increase limb fat mass whereas rosiglitazone was not significantly better than placebo. The effectiveness of these drugs did not vary according to whether the patients were receiving thymidine analogues.