Repurposing nucleoside reverse transcriptase inhibitors (NRTIs) to slow aging

Repurposing drugs already approved in the clinic to be used off-label as geroprotectors, compounds that combat mechanisms of aging, are a promising way to rapidly reduce age-related disease incidence in society. Several recent studies have found that a class of drugs-nucleoside reverse transcriptase inhibitors (NRTIs)-originally developed as treatments for cancers and human immunodeficiency virus (HIV) infection, could be repurposed to slow the aging process. Interestingly, these studies propose complementary mechanisms that target multiple hallmarks of aging. At the molecular level, NRTIs repress LINE-1 elements, reducing DNA damage, benefiting the hallmark of aging of 'Genomic Instability'. At the organellar level, NRTIs inhibit mitochondrial translation, activate ATF-4, suppress cytosolic translation, and extend lifespan in worms in a manner related to the 'Loss of Proteostasis' hallmark of aging. Meanwhile, at the cellular level, NRTIs inhibit the P2X7-mediated activation of the inflammasome, reducing inflammation and improving the hallmark of aging of 'Altered Intercellular Communication'. Future development of NRTIs for human aging health will need to balance out toxic side effects with the beneficial effects, which may occur in part through hormesis.

Insights into the mechanisms of telbivudine-induced myopathy associated with mitochondrial dysfunction

As a nucleotide analogue (NA), telbivudine was widely used in the treatment for chronic hepatitis B (CHB) by interfering with reverse transcriptase of hepatitis B virus. However, the use of NAs for hepatitis B treatment has been accompanied by numerous reports highlighting the occurrence of neuromyopathy, particularly in the case of telbivudine. This study aimed to investigate the underlying mechanisms responsible for telbivudine-induced myopathy. We established animal and cell models of telbivudine-induced myopathy using C57BL/6 mice and C2C12 cells, respectively. Our findings revealed that telbivudine significantly reduced mitochondrial DNA (mtDNA) copy number and caused increase of oxidative stress. Telbivudine treatment significantly inhibited mitochondrial complex I and IV expression, impairing the oxidative phosphorylation function of the respiratory chain. Modified Gomori trichrome (MGT) staining of the muscle sections displayed an increase in ragged red fibers (RRFs), indicating abnormal mitochondrial accumulation. In conclusion, our study provides compelling evidence suggesting that telbivudine-induced myopathy is associated with mitochondrial toxicity and impaired energy metabolism. The observed muscle pathology, depletion of mtDNA, elevation of oxidative stress and altered mitochondrial function support the hypothesis that telbivudine disrupts mitochondrial homeostasis, ultimately leading to muscle damage. This may be also a common mechanism for NAs to cause neuromyopathy.

Telbivudine-Induced Myopathy: Clinical Features, Histopathological Characteristics, and Risk Factors

BACKGROUND AND PURPOSE

Oral nucleos(t)ide analogs (NAs) are the mainstay treatment for chronic hepatitis B (CHB). Myotoxicity is an important extrahepatic effect related to NA treatment. Telbivudine is the NA for CHB that is frequently associated with muscle-related side effects. The risk factors for telbivudine-induced myopathy (TIM) are not yet clear.

METHODS

This study characterized the clinical, magnetic resonance images (MRI), and pathological features of 12 TIM cases. A group of telbivudine-tolerant (TT) patients with CHB who received regular telbivudine treatment during the same period without the occurrence of myopathy was collected. Demographic and clinical factors were compared between the patients with TIM and the TT controls. Factors independently associated with TIM were identified using logistic regression analysis.

RESULTS

The patients with TIM (males/females: 7/5, mean age: 57 years) developed myopathy after using telbivudine for a median period of 19.5 months. Muscle histopathology revealed abnormal proliferation, subsarcolemmal or sarcoplasmic accumulations, and ultrastructural defects of mitochondria. When compared with TT cases, patients with TIM had a lower estimated glomerular filtration rate and were more frequently positive for hepatitis B e antigen (HBeAg).

CONCLUSIONS

Mitochondrial abnormalities are characteristic histopathological features, and impaired renal function and HBeAg positivity are risk factors for TIM. Telbivudine-induced mitochondrial dysfunction and immune activation related to mitochondrial damage and HBeAg serostatus changes may underlie TIM. Constant clinical surveillance of myopathy during telbivudine treatment is needed due to the significant latency of its development. Dose adjustment for impaired renal function does not eliminate the risk of TIM occurrence.

Bile duct ligation enhances AZT CNS toxicity partly by impairing the expression and function of BCRP in rat brain

Breast cancer resistance protein (BCRP) is one of ATP-binding cassette (ABC) transporters in brain microvessel endothelial cells that transport their substrates from brain to blood, thus limiting substrates to crossing into brain through blood-brain barrier. Our previous works show that bile duct ligation (BDL) impairs expression and function of brain BCRP in rats. Since zidovudine (AZT) is BCRP substrate, we investigated whether impaired expression and function of BCRP increased brain distribution and toxicity of AZT in BDL-D7 rats. After administration of AZT (10 mg/kg, i.v.), BDL markedly increased brain AZT concentrations, compared with sham-operated (SO) rats. The ratio of AZT brain-to-plasma area under concentration curve (AUC) in BDL rats was increased to 1.6-folds of SO rats. After treatment with AZT (100 mg/kg every day, i.v.) for 7 days, BDL significantly impaired cognitive functions compared with SO rats, evidenced by the significantly decreased percentage of alternation in Y-maze test and prolonged escaped latency in two-way passive avoidance trial. Furthermore, AZT treatment caused significant decrease in copies of mitochondrial DNA and mitochondrial membrane potential in hippocampus of BDL rats. Moreover, AZT treatment caused a significant decrease of cortex microtubule-associated protein 2 and hippocampus synaptophysin levels in BDL rats. AZT-induced CNS adverse alterations in BDL rats were not observed in SO rats treated with AZT. In conclusion, BDL decreases the function and expression of brain BCRP in rats, leading to increased brain distribution of AZT, which in turn enhances AZT CNS toxicity, leading to mitochondrial dysfunction, neuronal damage, and ultimately cognitive dysfunction.

Metabolic, mitochondrial, renal and hepatic safety of enfuvirtide and raltegravir antiretroviral administration: Randomized crossover clinical trial in healthy volunteers

Context

Classical antiretroviral agents may acutely impact on metabolic, mitochondrial, renal and hepatic function in HIV-infected and uninfected persons. Fusion and integrase inhibitors are supposed to be safer, but have been scarcely investigated. To avoid any interference with HIV or other antiretrovirals, we assessed markers of these toxicities in healthy adult volunteers treated with Enfuvirtide (T20) or Raltegravir (RAL).

Methods

Twenty-six healthy participants were randomized to T20/90mg vs. placebo (n = 12) or RAL/400mg vs. placebo (n = 14) every 12h in two 7-day periods separated by a 4-week washout period. Major end-points were changes in lipid profile (total cholesterol, high-density-lipoprotein (HDL)-cholesterol, low-density-lipoprotein (LDL)-cholesterol, triglycerides), insulin resistance (glucose) and mitochondrial toxicity (mitochondrial DNA content–mtDNA–in peripheral blood mononuclear cells). Renal and hepatic toxicity (creatinine, alanine transaminase (AST), alanine aminotransferase (ALT), bilirubin and total plasma proteins) and overall safety were also analysed. Effect of period, treatment, and basal measures were evaluated for each end-point.

Results

Neither T20-administration nor RAL-administration yielded to any statistic significant change in the markers of metabolic, mitochondrial, renal or hepatic toxicity assessed. No symptoms indicative of drug toxicity were neither found in any subject.

Conclusions

In absence of HIV infection, or concomitant treatment, short-term exposure to T20 or RAL in healthy adult volunteers did not lead to any indicative changes in toxicity markers thus presuming the safe profile of both drugs.

Asymptomatic HIV People Present Different Profiles of sCD14, sRAGE, DNA Damage, and Vitamins, according to the Use of cART and CD4+ T Cell Restoration

We aimed to analyze markers of immune activation, inflammation, and oxidative stress in 92 asymptomatic HIV-infected patients according to the adequate (AR, >500 cells/mm³) or inadequate (IR, <500 cells/mm³) CD4⁺ T recovery and the presence or absence of antiretroviral treatment (cART). In relation to those newly diagnosed, they were divided into two groups, cART-naïve IR (nIR) and cART-naïve AR (nAR). Among those diagnosed more than five years ago, the following division was made: the cART-naïve long-term nonprogressors (LTNP); patient under cART and AR (tAR); and patients under cART and IR (tIR). We investigated the expression of soluble receptor for advanced glycation end products (sRAGE), high-mobility group-box protein −1 (HMGB1), soluble CD14 (sCD14), IL-8, IL-10, 8-isoprostane, vitamins, and DNA damage. We observed higher levels of sRAGE in tAR as compared to nIR, nAR, LTNP, and more sCD14 than in nIR and nAR. As for IL-10 levels, we found nIR > nAR > LTNP > tAR > tIR. Higher levels of 8-isoprostane were observed in nIR. LTNP presented a higher retinol dosage than tAR and less genotoxic damage induced by oxidative stress than the other groups. We suggest that the therapy, despite being related to lesser immune activation and inflammation, alters the vitamin profile and consequently increases the oxidative stress of patients. In addition, the lowest genotoxic index for LTNP indicates that both VL and cART could be responsible for the increased DNA damage. More studies are needed to understand the influence of cART on persistent immune activation and inflammation.

A Two-Way Steady-State Pharmacokinetic Interaction Study of Doravirine (MK-1439) and Dolutegravir

INTRODUCTION

Doravirine, a non-nucleoside reverse-transcriptase inhibitor in development for the treatment of patients with human immunodeficiency virus-1 infection, has potential to be used concomitantly in antiretroviral therapy with dolutegravir, an integrase strand transfer inhibitor. The pharmacokinetic interactions between these drugs were therefore assessed.

METHODS

Oral formulations of doravirine and dolutegravir were dosed both individually and concomitantly once daily in healthy adults. Twelve subjects (six were male), 23-42 years of age, were enrolled and 11 completed this phase I, open-label, three-period, fixed-sequence study per protocol; one subject was discontinued for a positive cotinine test at admission to period 2. In period 1, dolutegravir 50 mg was administered for 7 days. After a 7-day washout, doravirine 200 mg was dosed for 7 days in period 2, followed (without washout) by both doravirine and dolutegravir simultaneously for 7 days in period 3. Plasma samples were taken to determine dolutegravir and doravirine concentrations.

RESULTS

The steady-state concentration 24 h post-dose (C₂₄) of dolutegravir was not substantially altered by co-administration of doravirine multiple doses; area under the plasma concentration-time curve from dosing to 24 h post-dose (AUC_0-24), maximum concentration (C _max), and C₂₄ geometric mean ratios were 1.36, 1.43, and 1.27, respectively. The pharmacokinetics of doravirine was not affected by multiple doses of dolutegravir (geometric mean ratios: 1.00, 0.98, and 1.06 for AUC_0-24, C₂₄, and C _max, respectively). Both drugs were generally well tolerated.

CONCLUSION

The results of this study demonstrate that concomitant administration of doravirine and dolutegravir in healthy subjects causes no clinically significant alteration in the pharmacokinetic and safety profiles of the two drugs, thereby supporting further evaluation of co-administration of these agents for human immunodeficiency virus-1 treatment.

Off-Target Effects of Drugs that Disrupt Human Mitochondrial DNA Maintenance

Nucleoside reverse transcriptase inhibitors (NRTIs) were the first drugs used to treat human immunodeficiency virus (HIV) the cause of acquired immunodeficiency syndrome. Development of severe mitochondrial toxicity has been well documented in patients infected with HIV and administered NRTIs. In vitro biochemical experiments have demonstrated that the replicative mitochondrial DNA (mtDNA) polymerase gamma, Polg, is a sensitive target for inhibition by metabolically active forms of NRTIs, nucleotide reverse transcriptase inhibitors (NtRTIs). Once incorporated into newly synthesized daughter strands NtRTIs block further DNA polymerization reactions. Human cell culture and animal studies have demonstrated that cell lines and mice exposed to NRTIs display mtDNA depletion. Further complicating NRTI off-target effects on mtDNA maintenance, two additional DNA polymerases, Pol beta and PrimPol, were recently reported to localize to mitochondria as well as the nucleus. Similar to Polg, in vitro work has demonstrated both Pol beta and PrimPol incorporate NtRTIs into nascent DNA. Cell culture and biochemical experiments have also demonstrated that antiviral ribonucleoside drugs developed to treat hepatitis C infection act as off-target substrates for POLRMT, the mitochondrial RNA polymerase and primase. Accompanying the above-mentioned topics, this review examines: (1) mtDNA maintenance in human health and disease, (2) reports of DNA polymerases theta and zeta (Rev3) localizing to mitochondria, and (3) additional drugs with off-target effects on mitochondrial function. Lastly, mtDNA damage may induce cell death; therefore, the possibility of utilizing compounds that disrupt mtDNA maintenance to kill cancer cells is discussed.

Nucleoside reverse transcriptase inhibitors induced hepatocellular mitochondrial DNA lesions and compensatory enhancement of mitochondrial function and DNA repair

Nucleoside reverse transcriptase inhibitors (NRTIs) are the backbone of combined antiretroviral therapy (cART) and are widely used in anti-human immunodeficiency virus (HIV) therapy. Long-term administration of NRTIs can result in mitochondrial dysfunction in certain HIV-1-infected patients. However, NRTI-associated liver mitochondrial toxicity is not well known. Herein, the liver autopsy of acquired immune deficiency syndrome (AIDS) patients and the liver tissues of mice with 12 months of NRTI exposure were used to identify NRTI-associated liver toxicity with immunofluorescence, quantitative real-time polymerase chain reaction (qPCR), Amplex red and horseradish peroxidase, and cloning and sequencing. Laser capture microdissection was used to capture hepatocytes from liver tissues. We observed DNA oxidative damage and mitochondrial DNA (mtDNA) loss in the livers of AIDS patients, and cART patients had higher DNA oxidative damage and lower DNA repair function in liver tissues than non-cART patients. We also observed liver oxidative damage, increased DNA repair and mtDNA loss in mice with exposure to four different NRTIs for 12 months, and hepatocytes had no more mtDNA loss than liver tissues. Although NRTIs could induce mitochondrial hydrogen peroxide production, increased mitochondrial oxygen consumption was found with a Clark-type electrode. The captured hepatocytes had greater diversity in their mtDNA D-loop, dehydrogenase subunit1 (ND1) and ND4 than the controls. Long-term NRTI exposure induced single nucleotide variation in hepatocellular mtDNA D-loop, ND1 and ND4. Our findings indicate that NRTIs can induce liver mtDNA lesions, but simultaneously enhance mitochondrial function and mtDNA repair.

When Gender Identity Doesn't Equal Sex Recorded at Birth: The Role of the Laboratory in Providing Effective Healthcare to the Transgender Community

BACKGROUND

Transgender is an umbrella term used to describe individuals who identify with a gender incongruent to or variant from their sex recorded at birth. Affirming gender identity through a variety of social, medical, and surgical interventions is critical to the mental health of transgender individuals. In recent years, awareness surrounding transgender identities has increased, which has highlighted the health disparities that parallel this demographic. These disparities are reflected in the experience of transgender patients and their providers when seeking clinical laboratory services.

CONTENT

Little is known about the effect of gender-affirming hormone therapy and surgery on optimal laboratory test interpretation. Efforts to diminish health disparities encountered by transgender individuals and their providers can be accomplished by increasing social and clinical awareness regarding sex/gender incongruence and gaining insight into the physiological manifestations and laboratory interpretations of gender-affirming strategies. This review summarizes knowledge required to understand transgender healthcare including current clinical interventions for gender dysphoria. Particular attention is paid to the subsequent impact of these interventions on laboratory test utilization and interpretation. Common nomenclature and system barriers are also discussed.

SUMMARY

Understanding gender incongruence, the clinical changes associated with gender transition, and systemic barriers that maintain a gender/sex binary are key to providing adequate healthcare to transgender community. Transgender appropriate reference interval studies are virtually absent within the medical literature and should be explored. The laboratory has an important role in improving the physiological understanding, electronic medical system recognition, and overall social awareness of the transgender community.

HIV-associated cellular senescence: A contributor to accelerated aging

Due to the advent of antiretroviral therapy HIV is no longer a terminal disease and the HIV infected patients are becoming increasingly older. While this is a major success, with increasing age comes an increased risk for disease. The age-related comorbidities that HIV infected patients experience suggest that they suffer from accelerated aging. One possible contributor to this accelerated aging is cellular senescence, an age-associated response that can occur prematurely in response to stress, and that is emerging as a contributor to disease and aging. HIV patients experience several stressors such as the virus itself, antiretroviral drugs and to a lesser extent, substance abuse that can induce cellular senescence. This review summarizes the current knowledge of senescence induction in response to these stressors and their relation to the comorbidities in HIV patients. Cellular senescence may be a possible therapeutic target for these comorbidities.

Clinical challenges in HIV/AIDS: Hints for advancing prevention and patient management strategies

Acquired immune deficiency syndrome has been one of the most devastating epidemics of the last century. The current estimate for people living with the HIV is 36.9 million. Today, despite availability of potent and safe drugs for effective treatment, lifelong therapy is required for preventing HIV re-emergence from a pool of latently infected cells. However, recent evidence show the importance to expand HIV testing, to offer antiretroviral treatment to all infected individuals, and to ensure retention through all the cascade of care. In addition, circumcision, pre-exposure prophylaxis, and other biomedical tools are now available for included in a comprehensive preventive package. Use of all the available tools might allow cutting the HIV transmission in 2030. In this article, we review the status of the epidemic, the latest advances in prevention and treatment, the concept of treatment as prevention and the challenges and opportunities for the HIV cure agenda.

Mitochondrial DNA D-loop AG/TC transition mutation in cortical neurons of mice after long-term exposure to nucleoside analogues

With the wide application of combined antiretroviral therapy, the prognosis of human immunodeficiency virus (HIV)-1 infected patient has been significantly improved. However, long-term administration of antiretroviral drugs can result in various drug-associated toxicities. Among them, nucleoside analogues were confirmed to inhibit DNA polymerase gamma, resulting in mitochondrial toxicity. Our previous study indicated that long-term exposure of mice to nucleoside analogue could induce mitochondria DNA (mtDNA) loss in cortical neurons. Herein, we further identify mitochondrial toxicity of four nucleoside analogues (zidovudine (AZT), stavudine (D4T), lamivudine (3TC), and didanosine (DDI)) by cloning and sequencing mtDNA D-loop region in mice neurons captured with laser capture microdissection. The results showed that mutation of neuronal mtDNA D-loop sequences increased in mice treated with each of the four nucleoside analogues for 4 months and D4T and DDI induced more severe D-loop lesion than the other two nucleoside analogues. The major type of D-loop point mutations induced by four nucleoside analogues was transition, in particular of "A→G" and "T→C" transition, but the point transition sites were variable. Our findings suggest that long-term exposure to nucleoside analogue can result in mtDNA D-loop region lesion in mouse cortical neurons.

Antiretroviral therapy: current drugs

The rapid advances in drug discovery and the development of antiretroviral therapy is unprecedented in the history of modern medicine. The administration of chronic combination antiretroviral therapy targeting different stages of the human immunodeficiency virus' replicative life cycle allows for durable and maximal suppression of plasma viremia. This suppression has resulted in dramatic improvement of patient survival. This article reviews the history of antiretroviral drug development and discusses the clinical pharmacology, efficacy, and toxicities of the antiretroviral agents most commonly used in clinical practice to date.

Some HIV Antiretrovirals Increase Oxidative Stress and Alter Chemokine, Cytokine or Adiponectin Production in Human Adipocytes and Macrophages

Objectives

Adipose tissue from patients with HIV-related lipodystrophy presents a state of chronic inflammation. Altered expression of cytokines/adipokines and macrophage infiltration could be involved in patients’ insulin resistance and lipoatrophy. We tested whether antiretrovirals affected adipokine release by human subcutaneous adipocytes and cytokine/chemokine production by human macrophages and examined whether reactive oxygen species (ROS) hyperproduction was related to the effect of antiretrovirals.

Methods

Differentiated human adipocytes and PMA-THP-1 macrophages were treated with protease inhibitors (PIs: indinavir, nelfinavir, amprenavir, lopinavir, ritonavir and atazanavir) or nucleoside reverse transcriptase inhibitors (NRTIs: stavudine, zidovudine and abacavir) for 24–48 h without or with diphenylene iodonium (DPI), an inhibitor of oxidative stress. Lipid content was assessed by Oil Red O staining and ROS production by nitroblue tetrazolium (NBT) reduction. Cytokine/chemokines, adiponectin and leptin release was evaluated by ELISA or multiplex assays.

Results

In human adipocytes, PIs and NRTIs (except amprenavir, atazanavir and abacavir) reduced lipid content, adiponectin and leptin release and increased in parallel ROS production and monocyte chemoattractant protein (MCP)-1 and interleukin (IL)-6 release. The effects of PIs, but not of NRTIs, were prevented by the addition of DPI. In PMA-THP-1 macrophages, all PIs, but no NRTI, increased macrophage inflammatory protein-1α and MCP-1 release. Lopinavir, nelfinavir, zidovudine and stavudine markedly increased ROS production and release of IL-1β and tumour necrosis factor-α.

Conclusions

Some PIs altered adipokine secretion and lipid content through ROS production in human subcutaneous adipocytes. Thymidine analogues altered adipocyte functions but their effect on adipokine secretion was not reverted by ROS production inhibition. Increased chemokine/cytokine production by adipocytes and macrophages could be involved in macrophage recruitment and participate in lipoatrophy and insulin resistance.

Interaction of 2'-deoxyguanosine triphosphate analogue inhibitors of HIV reverse transcriptase with human mitochondrial DNA polymerase gamma

Mitochondrial toxicity is a limiting factor in the use of some nucleoside reverse transcriptase inhibitors of HIV. To further understand the impact of structural features on the incorporation and exonuclease removal of nucleoside monophosphate (MP) analogues by human mitochondrial DNA polymerase (pol gamma), transient kinetic studies were done with analogues of 2'-deoxyguanosine triphosphate. The kinetic parameters for the incorporation and removal of carbovir (CBV)-MP, dioxolane guanosine (DXG)-MP and 2',3'-dideoxy-2',3'-didehydroguanosine (d4G)-MP were studied with pol gamma holoenzyme. The importance of the ribose oxygen in incorporation by pol gamma was illustrated by an approximate 3,000-fold decrease in the incorporation efficiency of an analogue lacking the ribose oxygen (CBV-TP) relative to those containing a ribose oxygen (DXG-TP and d4G-TP). As a result, a comparison with previous data for the incorporation by HIV reverse transcriptase showed CBV-TP to be approximately 800-8,000-fold more selective for its antiviral target over pol gamma relative to the other guanosine analogues. However, DXG-TP and d4G-TP were found to be much more selective than previously reported values for mitochondrial toxic nucleoside analogues. Structural modelling based on sequence homology with other polymerase A family members suggests that an interaction between the ribose oxygen and arginine 853 in pol gamma may play a critical role in causing this differential incorporation. Exonuclease removal of a chain-terminating CBV-MP was also found to be more efficient by pol gamma. These results help to further elucidate the structure activity relationships for pol gamma and should aid in the design of more selective antiviral agents.

Clinical mitochondrial dysfunction in uninfected children born to HIV-infected mothers following perinatal exposure to nucleoside analogues

Clinical and biological observations of mitochondrial dysfunction in children exposed to zidovudine (azidothymidine, AZT) during the perinatal period rapidly followed similar observations in animal experiments. To date, two different disorders have been identified. The first, asymptomatic hyperlactatemia, is observed during treatment in one third of exposed newborns, and is reversible with treatment cessation. In rare cases, it is associated with symptomatic acidosis. Regression may be slow, taking up to several months after the end of the treatment. The long-term clinical consequences of this biochemical disturbance are unknown. The second disorder involves severe neurological symptoms, which become clinically detectable during the first 2 years of life. These symptoms are associated with a series of biochemical and ultrastructural changes consistent with persistent mitochondrial dysfunction. This latter phenomenon is rare, and affects only 0.3-0.5% of exposed children in the French pediatric cohort, in which observations continue. Despite initial controversy, several similar observations in other cohorts have since confirmed its occurrence. The pathophysiology of these two mitochondrial dysfunctions may differ. Continued efforts to identify and understand clinical mitochondrial toxicities are essential, given the intensification and diversification of perinatal prophylaxis strategies, and the number of pregnant women potentially involved.

Diseases of adipose tissue: genetic and acquired lipodystrophies

Human lipodystrophies represent a group of diseases characterized by altered body fat amount and/or repartition and major metabolic alterations with insulin resistance leading to diabetic complications and increased cardiovascular and hepatic risk. Genetic forms of lipodystrophies are rare. Congenital generalized lipodystrophy or Berardinelli-Seip syndrome, autosomal recessive, is characterized by a complete early lipoatrophy and severe insulin resistance and results, in most cases, from mutations either in the seipin gene of unknown function or AGPAT2 encoding an enzyme involved in triacylglycerol synthesis. The Dunnigan syndrome [FPLD2 (familial partial lipodystrophy of the Dunnigan type)] is due to mutations in LMNA encoding the lamin A/C, belonging to the complex group of laminopathies that could comprise muscular and cardiac dystrophies, neuropathies and syndromes of premature aging. Some FPLDs are linked to loss-of-function mutations in the PPAR-gamma gene (peroxisome-proliferator-activated receptor gamma; FPLD3) with severe metabolic alterations but a less severe lipodystrophy compared with FPLD2. The metabolic syndrome, acquired, represents the most common form of lipodystrophy. HIV-infected patients often present lipodystrophies, mainly related to side effects of antiretroviral drugs together with insulin resistance and metabolic alterations. Such syndromes help to understand the mechanisms involved in insulin resistance resulting from altered fat repartition and could benefit from insulin-sensitizing effects of lifestyle modifications or of specific medications.

New HIV drugs in development, 2005

Since the introduction of zidovudine 18 years ago, the treatment of HIV has been rapidly evolving. Current therapies target the HIV retrovirus successfully but contain their own perils. Active therapies with reduced adverse effects and long-term activity in the presence of, or reduced susceptibility to, antiviral resistance continue to be needed. Furthermore, more convenient agents that may facilitate adherence to therapy are a goal of new drug development. This review addresses these clinical needs, with a discussion of several new drugs currently in the clinical trial pipeline.