HIV-associated lipodystrophy: a review of underlying mechanisms and therapeutic options

New and emerging agents in the management of lipodystrophy in HIV-infected patients

Lipodystrophy remains a major long-term complication in human immunodeficiency virus-infected patients under antiretroviral (ARV) therapy. Patients may present with lipoatrophy or lipohypertrophy or both. The choice of treatments to improve fat redistribution depends on the form of lipodystrophy and its duration. Measures known to improve lipoatrophy are switches in ARV therapy (stavudine or zidovudine to abacavir or tenofovir) and filling interventions. Pioglitazone may be added to these measures, although any benefits appear small. Uridine and leptin were found to be disappointing so far. Regarding lipohypertrophy, diet and exercise, recombinant human growth hormone, and metformin may reduce visceral fat, but may worsen subcutaneous lipoatrophy. Surgical therapy may be required. Attractive pharmacologic treatments include growth hormone-releasing factor and leptin. Adiponectin and adiponectin receptors are promising therapeutic targets to explore.

Can serum hyaluronic acid replace simple non-invasive indexes to predict liver fibrosis in HIV/Hepatitis C coinfected patients?

BACKGROUND

Hyaluronic acid (HA) serum levels correlate with the histological stages of liver fibrosis in hepatitis C virus (HCV) monoinfected patients, and HA alone has shown very good diagnostic accuracy as a non-invasive assessment of fibrosis and cirrhosis. The aim of this study was to evaluate serum HA levels as a simple non-invasive diagnostic test to predict hepatic fibrosis in HIV/HCV-coinfected patients and to compare its diagnostic performance with other previously published simple non-invasive indexes consisting of routine parameters (HGM-1, HGM-2, Forns, APRI, and FIB-4).

METHODS

We carried out a cross-sectional study on 201 patients who all underwent liver biopsies and had not previously received interferon therapy. Liver fibrosis was determined via METAVIR score. The diagnostic accuracy of HA was assessed by area under the receiver operating characteristic curves (AUROCs).

RESULTS

The distribution of liver fibrosis in our cohort was 58.2% with significant fibrosis (F≥2), 31.8% with advanced fibrosis (F≥3), and 11.4% with cirrhosis (F4). Values for the AUROC of HA levels corresponding to significant fibrosis (F≥2), advanced fibrosis (F≥3) and cirrhosis (F4) were 0.676, 0.772, and 0.863, respectively. The AUROC values for HA were similar to those for HGM-1, HGM-2, FIB-4, APRI, and Forns indexes. The best diagnostic accuracy of HA was found for the diagnosis of cirrhosis (F4): the value of HA at the low cut-off (1182 ng/mL) excluded cirrhosis (F4) with a negative predictive value of 99% and at the high cut-off (2400 ng/mL) confirmed cirrhosis (F4) with a positive predictive value of 55%. By utilizing these low and high cut-off points for cirrhosis, biopsies could have theoretically been avoided in 52.2% (111/201) of the patients.

CONCLUSIONS

The diagnostic accuracy of serum HA levels increases gradually with the hepatic fibrosis stage. However, HA is better than other simple non-invasive indexes using parameters easily available in routine clinical practice only for the diagnosing of cirrhosis.

Molecular mechanisms controlling human adipose tissue development: insights from monogenic lipodystrophies

Appropriately functioning adipose tissue is essential for human health, a fact most clearly illustrated by individuals with lipodystrophy, who have impaired adipose development and often suffer severe metabolic disease as a result. Humans with obesity display a similar array of metabolic problems. This reflects failures in fat tissue function in obesity, which results in consequences similar to those seen when insufficient adipose tissue is present. Thus a better understanding of the molecules that regulate the development of fat tissue is likely to aid the generation of novel therapeutic strategies for the treatment of all disorders of altered fat mass. Single gene disruptions causing lipodystrophy can give unique insights into the importance of the proteins they encode in human adipose tissue development. Moreover, the mechanisms via which they cause lipodystrophy can reveal new molecules and pathways important for adipose tissue development and function as well as confirming the importance of molecules identified from studies of cellular and animal models.

Treinamento físico na síndrome lipodistrófica: revisão sistemática

Com a cronicidade da infecção pelo HIV, a partir do uso da terapia antirretroviral combinada (TARV), o indivíduo torna-se predisposto às alterações metabólicas e corporais denominadas síndrome lipodistrófica, que têm como consequência o risco aumentado para doenças cardiovasculares. Tornam-se necessários estudos com viabilidades terapêuticas com o intuito de melhorar a qualidade de vida destes pacientes. Neste contexto, o treinamento físico deve ser abordado como terapêutica para minimizar os efeitos deletérios da TARV. O objetivo desse artigo foi revisar na literatura as evidências científicas sobre o treinamento físico na síndrome lipodistrófica. O método utilizado foi uma revisão sistemática com a localização de artigos publicados entre 2000 e 2008 nas bases de dados PubMed e SciELO. As evidências científicas encontradas nos estudos analisados indicam que a maioria dos estudos, independente do tipo de treinamento, obtiveram melhoria significativa na composição corporal. Dessa forma, tornam-se necessário mais estudos investigando o treinamento físico no perfil lipídico, na resistência a insulina e nas alterações glicêmicas em pessoas vivendo com HIV/Aids.

[The role of the hospital pharmacist in the prevention, treatment and management of the side effects associated with antiretroviral treatment]

At present, the side effects associated with antiretroviral treatment are the main reasons for discontinuation of this kind of therapy, both in clinical trials and in regular clinical practise. On the other hand, due to the change of direction that our profession has suffered in recent years, we face the need to establish a different relationship with the patient, achieving direct and effective Pharmaceutical Care within a framework of shared responsibility for therapeutic results. Pharmacist interventions should be aimed at improving the quality of life of patients, which can only be achieved with a multidisciplinary approach and individualised and adjusted to new patterns of toxicity of the drugs currently used. The pharmacist who does this work must know how to interpret these side effects, giving accurate information to the patient about both pharmacological and non-pharmacological treatment and correct pharmaceutical follow-up which clearly sets forth the criteria for referral to medical appointments. The aim of this paper is to establish baselines so that the hospital pharmacist can perform clearly and uniformly in the prevention, identification and management of major side effects: gastrointestinal, cardiovascular, dermatological, at the central nervous system and kidney level, associated with antiretroviral therapy.

Mitochondrial dysfunction in CD4+ lymphocytes from stavudine-treated HIV patients

HIV therapy with nucleoside analogue reverse transcriptase inhibitors (NRTI) such as stavudine remains in widespread use in resource-limited nations due to potent efficacy, convenience of formulation and lack of practical alternatives. However, it remains unclear whether adverse side effects with NRTI include reduced mitochondrial respiratory function, particularly in peripheral blood lymphocytes (PBLs). The aim of this study was to determine whether stavudine-based highly active antiretroviral therapy (HAART) is associated with impaired mitochondrial respiratory transport chain function in patient derived CD4+PBLs. CD4+PBLs were isolated from asymptomatic HIV-infected patients treated with stavudine-HAART for 3 months (n=10), HIV-infected patients not on treatment (n=9) and uninfected controls (n=18). The basal mitochondrial oxygen consumption of CD4+PBLs from stavudine-treated patients was reduced relative to that of untreated HIV-infected patients and controls (stavudine treated group, 4.22 (25% 2.16, 75% 8.84); control uninfected, 11.2 (25% 3.95, 75% 16.6); untreated 18.1 (25% 11.8, 75% 37.9)ng oxygen atoms/min/ml). Maximal oxygen consumption (stimulated with the proton ionophore FCCP) in cells from stavudine treated patients was also reduced relative to that of untreated patients and controls (stavudine treated, 24.4+/-10.5; control uninfected, 50.6+/-39.5; untreated, 68.8+/-41.1 ng oxygen atoms/min/ml). Citrate synthase activities, relative mitochondrial volume (by electron microscopy) and mtDNA copy numbers per cell were not different between groups. Therapy with stavudine results in impaired mitochondrial function in CD4+PBLs that does not appear to be due to reduced mitochondrial volume or DNA content and cannot be attributed to infection with HIV.

The protease inhibitors ritonavir and saquinavir influence lipid metabolism: a pig model for the rapid evaluation of new drugs

BACKGROUND

Studies of the effects of antiretroviral drugs on lipid metabolism are limited by the availability of suitable models. We have thus developed an animal model utilising Göttingen mini-pigs. The normal lipid metabolism of mini-pigs closely reflects that of humans and they are expected to have similar reactions to antiretroviral drugs.

METHODS

The pigs were treated orally with high doses of the protease inhibitors ritonavir and saquinavir for 4 weeks. The model allows repeated concomitant biopsies from liver, muscle, adipose tissue and plasma samples.

RESULTS

The study showed a general decrease in polyunsaturated fatty acids; changes in both saturated and monounsaturated fatty acids were also apparent after antiretroviral treatment. The changes were observed after 4 weeks of treatment. At 4 weeks post-treatment, the levels of all fatty acids were lower compared with pretreatment levels, suggesting a prolonged effect of the antiretroviral drug treatment lasting beyond the 4 week post-treatment observation period.

CONCLUSIONS

The Göttingen mini-pig model is a promising animal model for rapid screening of the metabolic effects induced by antiretroviral drugs.

Chronic atypical neutrophilic dermatosis with lipodystrophy and elevated temperature (CANDLE) syndrome

Several syndromes manifest as recurrent daily fevers, skin lesions, and multisystem inflammation. We describe 4 patients with early-onset recurrent fevers, annular violaceous plaques, persistent violaceous eyelid swelling, low weight and height, lipodystrophy, hepatomegaly, and a range of visceral inflammatory manifestations. Laboratory abnormalities included chronic anemia, elevated acute-phase reactants, and raised liver enzymes. Histopathologic examination of lesional skin showed atypical mononuclear infiltrates of myeloid lineage and mature neutrophils. Our patients have a distinctive early-onset, chronic inflammatory condition with atypical or immature myeloid infiltrates in the skin. We propose the acronym CANDLE (chronic atypical neutrophilic dermatosis with lipodystrophy and elevated temperature) syndrome for this newly described disorder, which is probably genetic in origin.

Novel N-substituted benzimidazole CXCR4 antagonists as potential anti-HIV agents

The lead optimization of a series of N-substituted benzimidazole CXCR4 antagonists is described. Side chain modifications and stereochemical optimization led to substantial improvements in potency and protein shift to afford compounds with low nanomolar anti-HIV activity.

T-cell dysfunction in HIV-1 infection: targeting the inhibitors

Since AIDS emerged almost three decades ago, there have been considerable advances in the field of antiretroviral chemotherapy for those chronically infected with HIV-1. However, this therapy is noncurative and as our understanding of HIV-1 immunopathogenesis increases, it is becoming apparent that further therapeutic interventions are required to reverse the devastating effects of HIV-1 infection worldwide. While viral clearance remains the principle goal of HIV-1 treatment, this article describes immunotherapeutic options that target the immunological effects of the virus, to reduce its presence in the body and counteract viral-induced T-cell dysfunction and inhibition. Such approaches may augment existing antiretroviral therapy to overturn virus-induced T-cell anergy in the infected host, improving levels of immune control that reduce viremia and decrease the rate of transmission.

Optimising the medical management of hyperglycaemia in type 2 diabetes in the Middle East: pivotal role of metformin

AIMS

Increases in the prevalence of type 2 diabetes will likely be greater in the Middle East and other developing countries than in most other regions during the coming two decades, placing a heavy burden on regional healthcare resources.

METHODOLOGY

Medline search, examination of data from major epidemiological studies in the Middle Eastern countries.

RESULTS

The aetiology and pathophysiology of diabetes appears comparable in Middle Eastern and other populations. Lifestyle intervention is key to the management of diabetes in all type 2 diabetes patients, who should be encouraged strongly to diet and exercise. The options for pharmacologic therapy in the management of diabetes have increased recently, particularly the number of potential antidiabetic combinations. Metformin appears to be used less frequently to initiate antidiabetic therapy in the Middle East than in other countries. Available clinical evidence, supported by current guidelines, strongly favours the initiation of antidiabetic therapy with metformin in Middle Eastern type 2 diabetes patients, where no contraindications exist. This is due to its equivalent or greater efficacy relative to other oral antidiabetic treatments, its proven tolerability and safety profiles, its weight neutrality, the lack of clinically significant hypoglycaemia, the demonstration of cardiovascular protection for metformin relative to diet in the UK Prospective Diabetes Study and in observational studies, and its low cost. Additional treatments should be added to metformin and lifestyle intervention as diabetes progresses, until patients are receiving an intensive insulin regimen with or without additional oral agents.

CONCLUSIONS

The current evidence base strongly favours the initiation of antidiabetic therapy with metformin, where no contraindications exist. However, metformin may be under-prescribed in the Middle East.

LIPODYSTROPHY SYNDROME IN HIV-INFECTED CHILDREN ON HAART

Lipodystrophy syndrome (LD) is common in HIV-infected children, particularly those taking didanosine, stavudine or zidovudine. Lipo-atrophy in particular causes major stigmatisation and interferes with adherence. In addition, LD may have significant long-term health consequences, particularly cardiovascular. Since the stigmatising fat distribution changes of LD are largely permanent, the focus of management remains on early detection and arresting progression. Practical guidelines for surveillance and avoidance of LD in routine clinical practice are presented. The diagnosis of LD is described and therapeutic options are reviewed. The most important therapeutic intervention is to switch the most likely offending antiretroviral to a non-LD-inducing agent as soon as LD is recognised. Typically, when lipoatrophy or lipohypertrophy is diagnosed the thymidine nucleoside reverse transcriptase inhibitor (NRTI) is switched to a non-thymidine agent such as abacavir (or tenofovir in adults). Where dyslipidaemia is predominant, a dietician review is helpful, and the clinician may consider switching to a protease inhibitor-sparing regimen or to atazanavir.

Current and Novel Inhibitors of HIV Protease

The design, development and clinical success of HIV protease inhibitors represent one of the most remarkable achievements of molecular medicine. This review describes all nine currently available FDA-approved protease inhibitors, discusses their pharmacokinetic properties, off-target activities, side-effects, and resistance profiles. The compounds in the various stages of clinical development are also introduced, as well as alternative approaches, aiming at other functional domains of HIV PR. The potential of these novel compounds to open new way to the rational drug design of human viruses is critically assessed.

Prevalence of and clinical factors associated with lipoatrophy in HIV-infected Koreans receiving highly active antiretroviral therapy

Lipoatrophy is the long-term adverse effects developed in human immunodeficiency virus (HIV)-1-infected subjects receiving highly active antiretroviral therapy (HAART). This cross-sectional study aimed to evaluate the prevalence of and clinical factors associated with lipoatrophy in HIV-infected Koreans receiving HAART for more than 6 months. Lipoatrophy was diagnosed by concordance between physical examination and history taking performed by a single physician. Various covariates were examined, including diabetes mellitus (DM), lipid profiles after HAART, and HAART regimen and duration. Among total 144 patients (6 females and 138 males), 35 patients (24.3%) were diagnosed with lipoatrophy. The prevalence of lipoatrophy was significantly higher in females than that in males [83.3% (5/6) vs. 21.7% (30/138), p = 0.010] and higher in patients with DM than patients without DM [66.7% (4/6 DM) vs. 22.5% (31/138 non-DM), p = 0.030], or in patients with high total cholesterol levels than patients with low total cholesterol levels [31.9% (23/72 patients with high cholesterol) vs. 16.7% (12/72 patients with low cholesterol), p = 0.035]. Moreover, patients with stavudine treatment history (> 12 months) had a higher prevalence of lipoatrophy than patients who never received stavudine [50.0% (15/30) vs. 16.5% (17/103), p < 0.001]. In the multivariate logistic analysis, stavudine treatment for > 12 months (OR, 3.67; p = 0.011) and being female (OR, 24.93; p = 0.009) are independently associated with lipoatrophy. In conclusion, the prevalence of lipoatrophy in HIV-infected Koreans receiving HAART is not uncommon. Limited use of stavudine and regular monitoring are warranted to reduce lipoatrophy.

Augmentation of atrophic plantar soft tissue with an acellular dermal allograft: a series review

Treatment of plantar fat pad migration and atrophy has caused concern for decades. Patients can present with pain, callus formation, or ulceration. The purpose of this article is to review the results of a consecutive series of patients treated for fat pad atrophy of the plantar foot, using a minimally invasive implantation of an acellular human dermal allograft as a tissue augmentation. This material was chosen for the fat pad supplementation because of previous reports of success in tendon and ligament augmentation, wound healing, and interpositional arthroplasty.

Clinical management of HIV-associated lipodystrophy

PURPOSE OF REVIEW

Lipodystrophy or fat re-distribution, and its associated metabolic abnormalities, are common in HIV patients. The pathogenesis is multifactorial. This article provides an update on the latest findings of the different clinical management strategies that have been utilized in patients with lipodystrophy.

RECENT FINDINGS

Treatment strategies need to be different in those patients with lipoatrophy when compared with patients with central fat accumulation (lipohypertrophy). Most of the treatments studied have produced minimal or modest effects, which are not sustained when the therapy is discontinued. The treatment of associated metabolic abnormalities such as insulin resistance and hyperlipidemia should have similar goals to that in the non-HIV population, but is complicated by the fact that response may be worse and there is a need to consider drug-drug interactions with the antiretrovirals.

SUMMARY

Multiple complex strategies will need to be utilized in these patients to treat the different features seen in lipodystrophy in order to reduce their long-term cardiovascular risk. Further research is also needed to evaluate combination therapies and to identify the underlying mechanisms in order to develop novel therapies for the future.

HIV-1 protease inhibitor induced oxidative stress suppresses glucose stimulated insulin release: protection with thymoquinone

The highly active anti-retroviral therapy (HAART) regimen has considerably reduced the mortality rate in HIV-1 positive patients. However, long-term exposure to HAART is associated with a metabolic syndrome manifesting cardiovascular dysfunction, lipodystrophy, and insulin resistance syndrome (IRS). The inclusion of HIV-1 protease inhibitors (PIs) in HAART has been linked to the induction of IRS. Although several molecular mechanisms of PI-induced effects on insulin action have been postulated, the deleterious effects of PIs on insulin production by pancreatic beta-cells have not been fully investigated and therapeutic strategies to ameliorate insulin dysregulation at this level have not been targeted. The present study showed that exposure to several different PIs, nelfinavir (5-10 microM), saquinavir (5-10 microM) and atazanavir (8-20 microM), decreases glucose stimulated insulin secretion from rat pancreatic beta-cells (INS-1). Nelfinavir significantly increased reactive oxygen species (ROS) generation and suppressed cytosolic, but not mitochondrial superoxide dismutase (SOD) levels. Nelfinvair also decreased both glutathione and ATP and increased UCP2 levels in these cells. Simultaneous treatment with thymoquinone (TQ) (2.5 microM), an active ingredient of black seed oil, significantly inhibited the effect of nelfinavir on augmented ROS production and suppressed SOD levels. Both TQ and black seed oil exposure increased glucose stimulated insulin secretion and ameliorated the suppressive effect of nelfinavir. The present findings imply a direct role of ROS in PI induced deleterious effects on pancreatic beta-cells. Our findings also suggest that TQ may be used as a potential therapeutic agent to normalize the dysregulated insulin production observed in HAART treated patients.

Impact of different low-dose ritonavir regimens on lipids, CD36, and adipophilin expression

We investigated the relationship between ritonavir concentrations and changes in lipids, vascular inflammation markers, CD36, and adipophilin expression in volunteers randomly assigned to groups receiving 100 mg of ritonavir once daily or twice daily. In both groups decreases in high-density lipoprotein (HDL) (6%, P = 0.010; and 10%, P < 0.001, respectively) and CD36 (14%, P = 0.012; and 16%, P = 0.006, respectively) and increases in the vascular inflammation marker sCD40L (12%, P = 0.008; 19%, P = 0.003, respectively) were seen. Increases in adipophilin (30%, P = 0.044) and triglycerides (32%, P = 0.044) were seen only in the group receiving ritonavir twice daily. The ritonavir concentration in the plasma correlated with changes in triglycerides, HDL, and adipophilin (r = 0.34, P = 0.030; r = 0.33, P = 0.040; and r = 0.4, P = 0.01, respectively).