Do Non-Nucleoside Reverse Transcriptase Inhibitors Contribute to Lipodystrophy?

A new use for old drugs: identifying compounds with an anti-obesity effect using a high through-put semi-automated Caenorhabditis elegans screening platform

Obesity is one of the most common global health problems for all age groups with obese people at risk of a variety of associated health complications. Consequently, there is a need to develop new therapies that lower body fat without the side effects. However, obesity is a complex and systemic disease, so that in vitro results are not easily translatable to clinical situations. A promising way to circumnavigate these issues is to reposition already approved drugs for new treatments, enabling a more streamlined drug discovery process due to the availability of pre-existing pharmacological and toxicological datasets. Chemical libraries, such as the Prestwick Chemical Library of 1200 FDA approved drugs, are available for this purpose. We have developed a simple semi-automated whole-organism approach to screening the Prestwick Chemical Library for those compounds which reduce fat content using the model organism Caenorhabditis elegans.

Our whole-organism approach to high-throughput screening identified 9 “lead” compounds that reduced fat within 2 weeks in the model. Further screening and analysis provided 4 “hit” compounds (Midodrine, Vinpocetine, Fenoprofen and Lamivudine) that showed significant promise as drugs to reduce fat levels. The effects of these candidates were found to further reduce fat content in nematodes where an nhr-49/PPAR mutation resulted in “overweight” worms. Upon unblinding the “hit” compounds, they were found to have recently been shown to have anti-obesity effects in mammalian models too. In developing a whole-animal chemical screen to identify pharmacological agents as potential anti-obesity compounds, we demonstrate how chemical libraries can be rapidly and relatively cheaply profiled for active hits. Using the nematode Caenorhabditis elegans thus enables drugs to be assessed for applicability in humans and provides a new incentive to explore drug repurposing as a feasible and efficient way to identify new anti-obesity compounds.

[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.

A review of the safety and tolerability profile of the next-generation NNRTI etravirine

The next-generation nonnucleoside reverse transcriptase inhibitor (NNRTI) etravirine (TMC125) has demonstrated durable virologic efficacy in clinical trials involving >1000 treatment-experienced, NNRTI-resistant, HIV-1-infected patients. In this clinical safety review, we show etravirine to be well tolerated with a proven safety record. The nature and magnitude of adverse events observed during treatment suggest that etravirine may offer improved tolerability over existing antiretrovirals, including NNRTIs. Notably, adverse events reported with etravirine treatment are generally mild to moderate in severity. Rash has been shown to occur with a higher incidence in etravirine-treated patients versus placebo, but cases are generally mild to moderate, occur within the first few weeks, and resolve with continued use. In addition, the rate of adverse event-related discontinuations is low with etravirine. In summary, the safety and tolerability profile of etravirine, combined with its virologic efficacy, suggest that the drug may be a valuable option for treatment-experienced patients with HIV-1 infection.

Hierarchical modeling gave plausible estimates of associations between metabolic syndrome and components of antiretroviral therapy

OBJECTIVE

Hierarchical modeling has been proposed as a solution to the multiple exposure problem. We estimate associations between metabolic syndrome and different components of antiretroviral therapy using both conventional and hierarchical models.

STUDY DESIGN AND SETTING

We use discrete time survival analysis to estimate the association between metabolic syndrome and cumulative exposure to 16 antiretrovirals from four drug classes. We fit a hierarchical model where the drug class provides a prior model of the association between metabolic syndrome and exposure to each antiretroviral.

RESULTS

One thousand two hundred and eighteen patients were followed for a median of 27 months, with 242 cases of metabolic syndrome (20%) at a rate of 7.5 cases per 100 patient years. Metabolic syndrome was more likely to develop in patients exposed to stavudine, but was less likely to develop in those exposed to atazanavir. The estimate for exposure to atazanavir increased from hazard ratio of 0.06 per 6 months' use in the conventional model to 0.37 in the hierarchical model (or from 0.57 to 0.81 when using spline-based covariate adjustment).

CONCLUSION

These results are consistent with trials that show the disadvantage of stavudine and advantage of atazanavir relative to other drugs in their respective classes. The hierarchical model gave more plausible results than the equivalent conventional model.

HIV lipodystrophy and its metabolic consequences: implications for clinical practice

BACKGROUND

The introduction of highly active antiretroviral therapy (HAART) around 1996 markedly reduced mortality and morbidity from human immunodeficiency virus (HIV) infection. As life expectancy has improved, the chronic complications of HIV and HAART have become increasingly relevant.

SCOPE

This article provides an overview of the HIV-associated lipodystrophy, its pathogenesis and its clinical consequences (based on a search strategy in PubMed including literature published to November 2007).

FINDINGS

Lipodystrophy syndrome is characterized by abnormal fat distribution syndrome associated with metabolic disturbances and includes insulin resistance, deranged glucose and lipid metabolism. It is associated with increased risks of progression to type 2 diabetes and cardiovascular disease. Robust diagnostic criteria are required for lipodystrophy, and subsequent prospective cohort studies and randomized controlled trials are then required to determine the etiology and prognosis of lipodystrophy, and to evaluate therapeutic interventions for this consequence of HAART. Therapies to improve insulin resistance have been tried but they are frequently ineffective, and are limited by potential toxicity in this population. Hence, current management options for HIV associated lipodystrophy are limited and are mostly based on avoidance of risk factors and switching of antiretroviral drugs.

CONCLUSION

As the '3 by 5 strategy' of providing HIV drugs to the developing world is implemented worldwide, the numbers of patients adhering to antiretroviral medicines is dramatically increasing. One must be aware that in reducing the burden of acute retroviral disease, the treatments proposed might lead to significant rates of metabolic complications and further exacerbation of the epidemic of diabetes and cardiovascular disease.

Metabolic function and the prevalence of lipodystrophy in a population of HIV-infected African subjects receiving highly active antiretroviral therapy

OBJECTIVE

This study measured the prevalence of lipodystrophy and the metabolic effects of highly active antiretroviral therapy (HAART) in HIV-infected African subjects.

METHODS

Prevalence was measured in 571 Rwandans receiving HAART for > or = 6 months. Metabolic variables were measured in 100 HIV-positive adults with lipodystrophy, 50 HIV-positive nonlipodystrophic adults, and 50 HIV-negative controls.

RESULTS

A HAART regimen of stavudine, lamivudine, and nevirapine was used by 81.6% of subjects; none received protease inhibitors. Lipodystrophy was observed in 34% (48.5% in urban groups and 17.3% in rural groups) of subjects, with a prevalence of 69.6% in those receiving HAART for >72 weeks. Peripheral lipoatrophy combined with abdominal lipohypertrophy was observed in 72% of lipodystrophic subjects. HIV-positive adults with lipodystrophy had a significantly higher waist-to-hip ratio (WHR; 0.99 +/- 0.05 vs. 0.84 +/- 0.03: P < 0.0005) than HIV-positive nonlipodystrophic adults. Total cholesterol concentrations (median [interquartile range], mmol/L) were significantly higher in the HIV-positive adults with lipodystrophy (3.60 [1.38]) than in HIV-positive nonlipodystrophic adults (3.19 [0.65]; P < 0.005) and control (3.13 [0.70]; P < 0.0005) groups. Impaired fasting glucose was observed in 18% of HIV-positive adults with lipodystrophy, 16% of HIV-positive nonlipodystrophic adults, and 2% of controls, but insulin levels did not differ.

CONCLUSIONS

African subjects with lipodystrophy have increased WHR, glucose, and cholesterol levels. Glucose concentrations are also elevated in nonlipodystrophic HIV-positive subjects. Therefore, factors other than body fat redistribution contribute to the glucose intolerance.