Tenofovir-Associated Kidney Dysfunction and Bone Fracture: A Case Report and Literature Review

Tenofovir is an integral part of antiretroviral therapy used to treat HIV. Long-term use of tenofovir has been associated with decreased glomerular filtration rate, leading to chronic kidney disease, as well as acidosis, electrolyte imbalances, and tubular dysfunction. Tenofovir can also disrupt bone health by decreasing renal phosphate absorption, contributing to osteomalacia. This leads to disruption in mineral metabolism, elevated parathyroid hormone levels, and ultimately, low bone mineral density. Replacing tenofovir with alternative antiretroviral therapy can improve kidney function if done early in the course of the disease. Here, we discuss a case of a 65-year-old woman with HIV who presented with advanced renal failure and hypophosphatemia-induced bone fracture attributed to long-term use of tenofovir. We conclude monitoring kidney function and considering alternative antiretroviral therapy is important to prevent and manage these side effects in patients on long-term tenofovir therapy.

Determinants of early change in serum creatinine after initiation of dolutegravir-based antiretroviral therapy in South Africa

AIMS

Dolutegravir increases serum creatinine by inhibiting its renal tubular secretion and elimination. We investigated determinants of early changes in serum creatinine in a southern African cohort starting first-line dolutegravir-based antiretroviral therapy (ART).

METHODS

We conducted a secondary analysis of data from participants in a randomized controlled trial of dolutegravir, emtricitabine and tenofovir disoproxil fumarate (TDF) or tenofovir alafenamide fumarate (TAF) (ADVANCE, NCT03122262). We assessed clinical, pharmacokinetic and genetic factors associated with change in serum creatinine from baseline to Week 4 using linear regression models adjusted for age, sex, baseline serum creatinine, HIV-1 RNA concentration, CD4 T-cell count, total body weight and co-trimoxazole use.

RESULTS

We included 689 participants, of whom 470 had pharmacokinetic data and 315 had genetic data. Mean change in serum creatinine was 11.3 (SD 9.9) μmol.L-1. Factors that were positively associated with change in serum creatinine at Week 4 were increased log dolutegravir area under the 24-h concentration-time curve (change in creatinine coefficient [β] = 2.78 μmol.L-1 [95% confidence interval (CI) 0.54, 5.01]), TDF use (β = 2.30 [0.53, 4.06]), male sex (β = 5.20 [2.92, 7.48]), baseline serum creatinine (β = -0.22 [-0.31, -0.12]) and UGT1A1 rs929596 A→G polymorphism with a dominant model (β = -2.33 [-4.49, -0.17]). The latter did not withstand correction for multiple testing.

CONCLUSIONS

Multiple clinical and pharmacokinetic factors were associated with early change in serum creatinine in individuals initiating dolutegravir-based ART. UGT1A1 polymorphisms may play a role, but further research on genetic determinants is needed.

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

OBJECTIVES

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

RESEARCH METHODS AND PROCEDURES

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

RESULTS

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

CONCLUSIONS

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

Pyruvate dehydrogenase is a potential mitochondrial off-target for gentamicin based on in silico predictions and in vitro inhibition studies

During the drug development process, organ toxicity leads to an estimated failure of one-third of novel chemical entities. Drug-induced toxicity is increasingly associated with mitochondrial dysfunction, but identifying the underlying molecular mechanisms remains a challenge. Computational modeling techniques have proven to be a good tool in searching for drug off-targets. Here, we aimed to identify mitochondrial off-targets of the nephrotoxic drugs tenofovir and gentamicin using different in silico approaches (KRIPO, ProBis and PDID). Dihydroorotate dehydrogenase (DHODH) and pyruvate dehydrogenase (PDH) were predicted as potential novel off-target sites for tenofovir and gentamicin, respectively. The predicted targets were evaluated in vitro, using (colorimetric) enzymatic activity measurements. Tenofovir did not inhibit DHODH activity, while gentamicin potently reduced PDH activity. In conclusion, the use of in silico methods appeared a valuable approach in predicting PDH as a mitochondrial off-target of gentamicin. Further research is required to investigate the contribution of PDH inhibition to overall renal toxicity of gentamicin.

Examining Chronic Inflammation, Immune Metabolism, and T Cell Dysfunction in HIV Infection

Chronic Human Immunodeficiency Virus (HIV) infection remains a significant challenge to global public health. Despite advances in antiretroviral therapy (ART), which has transformed HIV infection from a fatal disease into a manageable chronic condition, a definitive cure remains elusive. One of the key features of HIV infection is chronic immune activation and inflammation, which are strongly associated with, and predictive of, HIV disease progression, even in patients successfully treated with suppressive ART. Chronic inflammation is characterized by persistent inflammation, immune cell metabolic dysregulation, and cellular exhaustion and dysfunction. This review aims to summarize current knowledge of the interplay between chronic inflammation, immune metabolism, and T cell dysfunction in HIV infection, and also discusses the use of humanized mice models to study HIV immune pathogenesis and develop novel therapeutic strategies.

Successful Treatment of Tenofovir Alafenamide-Induced Lactic Acidosis: A Case Report

Nucleoside or nucleotide analogues (NAs) have the potential to cause lactic acidosis by inhibiting DNA polymerase-γ of human mitochondria and impairing aerobic metabolism. Patients may be asymptomatic, have mild non-specific symptoms, or present in multisystem organ failure. There is a paucity of data to guide management of life-threatening lactic acidosis due to NA therapy. Here we describe a case of a 60-year old critically ill male with decompensated cirrhosis secondary to hepatitis B virus (HBV) infection who developed severe lactic acidosis (13.8 mmol/L) 2 days after initiation of tenofovir alafenamide (TAF). All other possible etiologies for the elevated lactate were ruled out. Lactic acidosis resolved rapidly with TAF discontinuation and supplementation with cofactors supporting mitochondrial oxidative phosphorylation, including coenzyme Q10, levocarnitine, riboflavin, and thiamine. This case highlights the ability of TAF to cause lactic acidosis early after therapy initiation, especially in susceptible hosts, and reviews the potential role for cofactor supplementation for drug-induced mitochondrial injury.

HIV Replication Increases the Mitochondrial DNA Content of Plasma Extracellular Vesicles

Extracellular vesicles (EVs) and their cargo have been studied intensively as potential sources of biomarkers in HIV infection; however, their DNA content, particularly the mitochondrial portion (mtDNA), remains largely unexplored. It is well known that human immunodeficiency virus (HIV) infection and prolonged antiretroviral therapy (ART) lead to mitochondrial dysfunction and reduced mtDNA copy in cells and tissues. Moreover, mtDNA is a well-known damage-associated molecular pattern molecule that could potentially contribute to increased immune activation, oxidative stress, and inflammatory response. We investigated the mtDNA content of large and small plasma EVs in persons living with HIV (PLWH) and its implications for viral replication, ART use, and immune status. Venous blood was collected from 196 PLWH, ART-treated or ART-naïve (66 with ongoing viral replication, ≥20 copies/mL), and from 53 HIV-negative persons, all recruited at five HIV testing or treatment centers in Burkina Faso. Large and small plasma EVs were purified and counted, and mtDNA level was measured by RT-qPCR. Regardless of HIV status, mtDNA was more abundant in large than small EVs. It was more abundant in EVs of viremic than aviremic and control participants and tended to be more abundant in participants treated with Tenofovir compared with Zidovudine. When ART treatment was longer than six months and viremia was undetectable, no variation in EV mtDNA content versus CD4 and CD8 count or CD4/CD8 ratio was observed. However, mtDNA in large and small EVs decreased with years of HIV infection and ART. Our results highlight the impact of viral replication and ART on large and small EVs' mtDNA content. The mechanisms underlying the differential incorporation of mtDNA into EVs and their effects on the surrounding cells warrant further investigation.

Spirulina platensis Ameliorates Oxidative Stress Associated with Antiretroviral Drugs in HepG2 Cells

Lately, Spirulina platensis (SP), as an antioxidant, has exhibited high potency in the treatment of oxidative stress, diabetes, immune disorder, inflammatory stress, and bacterial and viral-related diseases. This study investigated the possible protective role of Spirulina platensis against ARV-induced oxidative stress in HepG2 cells. Human liver (HepG2) cells were treated with ARVs ((Lamivudine (3TC): 1.51 µg/mL, tenofovir disoproxil fumarate (TDF): 0.3 µg/mL and Emtricitabine (FTC): 1.8 µg/mL)) for 96 h and thereafter treated with 1.5 µg/mL Spirulina platensis for 24 h. After the treatments, the gene and protein expressions of the antioxidant response pathway were determined using a quantitative polymerase chain reaction (qPCR) and Western blots. The results show that Spirulina platensis decreased the gene expressions of Akt (p < 0.0001) and eNOS (↓p < 0.0001) while, on the contrary, it increased the transcript levels of NRF-2 (↑p = 0.0021), Keap1 (↑p = 0.0002), CAT (↑p < 0.0001), and NQO-1 (↑p = 0.1432) in the HepG2 cells. Furthermore, the results show that Spirulina platensis also decreased the protein expressions of NRF-2 (↓p = 0.1226) and pNRF-2 (↓p = 0.0203). Interestingly, HAART-SP induced an NRF-2 pathway response through upregulating NRF-2 (except for FTC-SP) (↑p < 0.0001), CAT (↑p < 0.0001), and NQO-1 (except for FTC-SP) (↑p < 0.0001) mRNA expression. In addition, NRF-2 (↑p = 0.0085) and pNRF-2 (↑p < 0.0001) protein expression was upregulated in the HepG2 cells post-exposure to HAART-SP. The results, therefore, allude to the fact that Spirulina platensis has the potential to mitigate HAART-adverse drug reactions (HAART toxicity) through the activation of antioxidant response in HepG2 cells. We hereby recommend further studies on Spirulina platensis and HAART synergy.

Skeletal muscle mitochondrial dysfunction in contemporary antiretroviral therapy: a single cell analysis

OBJECTIVE

To quantify mitochondrial function in skeletal muscle of people treated with contemporary antiretroviral therapy.

DESIGN

Cross-sectional observational study.

METHODS

Quantitative multiplex immunofluorescence was performed to determine mitochondrial mass and respiratory chain complex abundance in individual myofibres from tibialis anterior biopsies. Individual myofibres were captured by laser microdissection and mitochondrial DNA (mtDNA) content and large-scale deletions were measured by real-time PCR.

RESULTS

Forty-five antiretroviral therapy (ART)-treated people with HIV (PWH, mean age 58 years, mean duration of ART 125 months) were compared with 15 HIV negative age-matched controls. Mitochondrial complex I (CI) deficiency was observed at higher proportional levels in PWH than negative controls ( P = 0.008). Myofibre mitochondrial mass did not differ by HIV status. No ART class was significantly associated with mitochondrial deficiency, including prior exposure to historical NRTIs (nucleoside analogue reverse transcriptase inhibitors) associated with systemic mitochondrial toxicity. To exclude an effect of untreated HIV, we also studied skeletal muscle from 13 ART-naive PWH (mean age 37). These showed negligible CI defects, as well as comparable myofibre mitochondrial mass to ART-treated PWH. Most CI-deficient myofibres contained mtDNA deletions. No mtDNA depletion was detected.

CONCLUSION

Here, we show that PWH treated with contemporary ART have mitochondrial dysfunction in skeletal muscle, exceeding that expected due to age alone. Surprisingly, this was not mediated by prior exposure to mitochondrially toxic NRTIs, suggesting novel mechanisms of mitochondrial dysfunction in contemporary ART-treated PWH. These findings are relevant for better understanding successful ageing in PWH.

The Potential of Spirulina platensis to Ameliorate the Adverse Effects of Highly Active Antiretroviral Therapy (HAART)

The human immunodeficiency virus (HIV) is one of the most prevalent diseases globally. It is estimated that 37.7 million people are infected with HIV globally, and 8.2 million persons are infected with the virus in South Africa. The highly active antiretroviral therapy (HAART) involves combining various types of antiretroviral drugs that are dependent on the infected person’s viral load. HAART helps regulate the viral load and prevents its associated symptoms from progressing into acquired immune deficiency syndrome (AIDS). Despite its success in prolonging HIV-infected patients’ lifespans, the use of HAART promotes metabolic syndrome (MetS) through an inflammatory pathway, excess production of reactive oxygen species (ROS), and mitochondrial dysfunction. Interestingly, Spirulina platensis (SP), a blue-green microalgae commonly used as a traditional food by Mexican and African people, has been demonstrated to mitigate MetS by regulating oxidative and inflammatory pathways. SP is also a potent antioxidant that has been shown to exhibit immunological, anticancer, anti-inflammatory, anti-aging, antidiabetic, antibacterial, and antiviral properties. This review is aimed at highlighting the biochemical mechanism of SP with a focus on studies linking SP to the inhibition of HIV, inflammation, and oxidative stress. Further, we propose SP as a potential supplement for HIV-infected persons on lifelong HAART.

Divergent effects of HIV reverse transcriptase inhibitors on pancreatic beta-cell function and survival: Potential role of oxidative stress and mitochondrial dysfunction

Antiretroviral therapy (ART), a life-saving treatment strategy in HIV/AIDS, has been implicated in increasing the risk of type 2 diabetes mellitus (T2DM). Direct damaging effects on beta-cell function and survival by either non-nucleoside reverse transcriptase inhibitors (NNRTIs) or nucleoside/tide reverse transcriptase inhibitors (NRTIs) may predispose individuals to developing T2DM or if already type 2 diabetic, to insulin dependency. The aim of this study was to investigate the effects of the NNRTIs efavirenz, rilpivirine and doravirine, and the NRTIs tenofovir disoproxil fumarate and emtricitabine, on beta-cell function and survival while suggesting potential cellular and molecular mechanism(s). Our results show contrasting effects within the NNRTI class as doravirine did not cause damaging effects in the rat insulinoma INS-1E cells while efavirenz and rilpivirine reduced insulin release and cell viability, and induced apoptosis in INS-1E cells. Additionally, efavirenz and rilpivirine increased ROS generation, disrupted Δψm and upregulated the mRNA and protein expression of CHOP and GRP78, key markers of endoplasmic reticulum stress. In silico docking studies predict a possible inhibition of the mitochondrial ATP synthase by rilpivirine. On the contrary, both the NRTIs tenofovir disoproxil fumarate and emtricitabine did not affect GSIS, cell viability and apoptosis/necrosis levels in INS-1E cells. The deleterious effects observed in beta-cells exposed to efavirenz or rilpivirine may be, at least partially, mediated by oxidative stress and mitochondrial toxicity. These findings provide potential mechanism(s) by which efavirenz and rilpivirine may contribute to the pathogenesis of T2DM and the progression of T2DM to insulin dependency in HIV-infected type 2 diabetics.

Rhodococcus as A Versatile Biocatalyst in Organic Synthesis

The application of purified enzymes as well as whole-cell biocatalysts in synthetic organic chemistry is becoming more and more popular, and both academia and industry are keen on finding and developing novel enzymes capable of performing otherwise impossible or challenging reactions. The diverse genus Rhodococcus offers a multitude of promising enzymes, which therefore makes it one of the key bacterial hosts in many areas of research. This review focused on the broad utilization potential of the genus Rhodococcus in organic chemistry, thereby particularly highlighting the specific enzyme classes exploited and the reactions they catalyze. Additionally, close attention was paid to the substrate scope that each enzyme class covers. Overall, a comprehensive overview of the applicability of the genus Rhodococcus is provided, which puts this versatile microorganism in the spotlight of further research.

Initial Antiretroviral Therapy in an Integrase Inhibitor Era: Can We Do Better?

With the second-generation integrase inhibitors (dolutegravir and bictegravir) extending the attributes of earlier integrase inhibitors, three-drug regimens containing integrase inhibitors plus two nucleos(t)ide reverse transcriptase inhibitors are now widely recommended for first-line (initial) treatment of human immunodeficiency virus-1 infection. Led by dolutegravir plus lamivudine, two-drug therapy is emerging as a way to reduce antiretroviral therapy cost and adverse effects without compromising treatment options should virologic failure occur. Initial two-drug therapy has limitations, including the relative incompatibility with the coemerging concept of same-day antiretroviral therapy initiation.

DNA polymerase-γ hypothesis in nucleoside reverse transcriptase-induced mitochondrial toxicity revisited: A potentially protective role for citrus fruit-derived naringenin?

Nucleoside reverse transcriptase inhibitors (NRTIs) form the backbone in combination antiretroviral therapy (cARVs). They halt chain elongation of the viral cDNA by acting as false substrates in counterfeit incorporation mechanism to viral RNA-dependent DNA polymerase. In the process genomic DNA polymerase as well as mitochondrial DNA (mtDNA) polymerase-γ (which has a much higher affinity for these drugs at therapeutic doses) are also impaired. This leads to mitochondrial toxicity that manifests clinically as mitochondrial myopathy, peripheral neuropathy, hyperlactatemia or lactic acidosis and lipoatrophy. This has led to the revision of clinical guidelines by World Health Organization to remove stavudine from first-line listing in the treatment of HIV infections. Recent reports have implicated oxidative stress besides mtDNA polymerase-γ hypothesis in NRTI-induced metabolic complications. Reduced plasma antioxidant concentrations have been reported in HIV positive patients on cARVs but clinical intervention with antioxidant supplements have not been successful either due to low efficacy or poor experimental designs. Citrus fruit-derived naringenin has previously been demonstrated to possess antioxidant and free radical scavenging properties which could prevent mitochondrial toxicity associated with these drugs. This review revisits the controversy surrounding mtDNA polymerase-γ hypothesis and evaluates the potential benefits of naringenin as a potent anti-oxidant and free radical scavenger which as a nutritional supplement or therapeutic adjunct could mitigate the development of mitochondrial toxicity associated with these drugs.

Twenty-Five Years of Lamivudine: Current and Future Use for the Treatment of HIV-1 Infection

Supplemental Digital Content is Available in the Text.

Innovation in medicine is a dynamic, complex, and continuous process that cannot be isolated to a single moment in time. Anniversaries offer opportunities to commemorate crucial discoveries of modern medicine, such as penicillin (1928), polio vaccination (inactivated, 1955; oral, 1961), the surface antigen of the hepatitis B virus (1967), monoclonal antibodies (1975), and the first HIV antiretroviral drugs (zidovudine, 1987). The advent of antiretroviral drugs has had a profound effect on the progress of the epidemiology of HIV infection, transforming a terminal, irreversible disease that caused a global health crisis into a treatable but chronic disease. This result has been driven by the success of antiretroviral drug combinations that include nucleoside reverse transcriptase inhibitors such as lamivudine. Lamivudine, an L-enantiomeric analog of cytosine, potently affects HIV replication by inhibiting viral reverse transcriptase enzymes at concentrations without toxicity against human polymerases. Although lamivudine was approved more than 2 decades ago, it remains a key component of first-line therapy for HIV because of its virological efficacy and ability to be partnered with other antiretroviral agents in traditional and novel combination therapies. The prominence of lamivudine in HIV therapy is highlighted by its incorporation in recent innovative treatment strategies, such as single-tablet regimens that address challenges associated with regimen complexity and treatment adherence and 2-drug regimens being developed to mitigate cumulative drug exposure and toxicities. This review summarizes how the pharmacologic and virologic properties of lamivudine have solidified its role in contemporary HIV therapy and continue to support its use in emerging therapies.

Safety of elvitegravir, cobicistat, emtricitabine, and tenofovir alafenamide in HIV-1-infected adults with end-stage renal disease on chronic haemodialysis: an open-label, single-arm, multicentre, phase 3b trial

BACKGROUND

Current treatment for HIV-infected individuals with renal failure on haemodialysis frequently requires complex regimens with multiple pills. A daily single-tablet regimen of coformulated elvitegravir, cobicistat, emtricitabine, and tenofovir alafenamide is approved in Europe, the USA, and in other regions for use in HIV-1-infected individuals with mild-to-moderate chronic kidney disease (creatinine clearance 30-69 mL/min). We aimed to assess the safety, efficacy, and pharmacokinetics of this regimen in HIV-infected adults with end-stage renal disease on chronic haemodialysis.

METHODS

We did an open-label, single-arm, multicentre, phase 3b trial at 26 outpatient clinics in Austria, France, Germany, and the USA. Participants were HIV-1-infected adults with end-stage renal disease (creatinine clearance <15 mL/min), on chronic haemodialysis for at least 6 months before screening. Virological suppression (ie, plasma HIV-1 RNA <50 copies per mL) on a stable antiretroviral regimen was required for at least 6 months before screening with a CD4 count of at least 200 cells per μL. We switched all participants to coformulated elvitegravir 150 mg, cobicistat 150 mg, emtricitabine 200 mg, and tenofovir alafenamide 10 mg once daily, taken after haemodialysis for up to 96 weeks. We did assessments at study visits at weeks 2, 4, 8, 12, 24, 36, and 48, and every 12 weeks thereafter up to 96 weeks. The primary endpoint was the incidence of treatment-emergent adverse events of grade 3 or higher up to week 48. All participants who received at least one dose of study drug were included in the primary analysis. This study is registered with ClinicalTrials.gov (NCT02600819) and is closed to new participants.

FINDINGS

Between Feb 1, and Nov 3, 2016, 55 participants were enrolled and received at least one dose of study drug. Through week 48, 18 of 55 participants (33%, 95% CI 20-45) had an adverse event of grade 3 or higher on study treatment. Treatment-emergent grade 3 or higher adverse events that occurred in more than one participant included anaemia, osteomyelitis, prolonged electrocardiogram QT, fluid overload, hyperkalaemia, hypertension, and hypotension (all n=2). No adverse event of grade 3 or higher was considered by the site investigators to be treatment related. Three participants (5%, 95% CI 0-11) discontinued treatment because of adverse events; one of these (grade 1 allergic pruritus) was considered treatment related. Treatment-related adverse events were reported for six individuals (11%, 95% CI 3-19), the most common of which was nausea (in four individuals [7%]); all treatment-related adverse events were grade 1 or 2 in severity.

INTERPRETATION

At 48 weeks, switching to the single-tablet regimen of elvitegravir, cobicistat, emtricitabine, and tenofovir alafenamide was well tolerated. This regimen might provide a tolerable and convenient option for ongoing treatment of HIV-1 infection in adults with end-stage renal disease on chronic haemodialysis.

FUNDING

Gilead Sciences.

Impact of Alcohol on HIV Disease Pathogenesis, Comorbidities and Aging: Integrating Preclinical and Clinical Findings

Short Summary

: Effective combined antiretroviral therapy regimens have extended survival of persons living with HIV (PLWH). Heavy alcohol consumption is common in PLWH. This overview integrates evidence from clinical and preclinical research to identify salient alcohol-related mechanisms and comorbidities contributing to disease pathogenesis and accelerated aging and senescence in PLWH.

Endocrinological aspects of HIV infection

PURPOSE

Patients with human immunodeficiency virus (HIV) are living longer with effective antiretroviral therapies and are enjoying near normal life span. Therefore, they are encountering endocrine issues faced by the general population along with those specific to HIV infection. The purpose of this article is to review the common endocrine aspects of HIV infection, and the early detection and management strategies for these complications.

METHODS

Recent literature on HIV and endocrine disease was reviewed.

RESULTS

HIV can influence endocrine glands at several levels. Endocrine glandular function may be altered by the direct effect of HIV viral proteins, through generation of systemic and local cytokines and the inflammatory response and via glandular involvement with opportunistic infections and HIV-related malignancies. Endocrine disorders seen in people with HIV include metabolic issues related to obesity such as diabetes, hyperlipidemia, lipohypertrophy, lipoatrophy and lipodystrophy and contribute significantly to quality of life, morbidity and mortality. In addition, hypogonadism, osteopenia and osteoporosis are also more prevalent in the patients with HIV. Although disorders of hypothalamic-pituitary-adrenal axis resulting in adrenal insufficiency can be life threatening, these along with thyroid dysfunction are being seen less commonly in the antiretroviral therapy (ART) era. ARTs have greatly improved life expectancy in people living with HIV but can also have adverse endocrine effects.

CONCLUSIONS

Clinicians need to have a high index of suspicion for endocrine abnormalities in people with HIV as they can be potentially life threatening if untreated. Endocrine evaluation should be pursued as in the general population, with focus on prevention, early detection and treatment to improve quality of life and longevity.

Return-to-health effect of modern combined antiretroviral therapy potentially predisposes HIV patients to hepatic steatosis

Prevalence and risk factors for hepatic steatosis (HS) in the human immunodeficiency virus (HIV)-positive population of western countries are controversially discussed and potentially confounded by coinfection with viral hepatitis. Significant HS (more than 10% of hepatocytes) can be accurately assessed using controlled attenuation parameter (CAP) determination. Aim of this study was to assess prevalence and factors associated with significant HS in HIV monoinfected patients.A total of 364 HIV-infected patients (289 monoinfected) were included in this prospective, cross-sectional study. All patients underwent CAP determination. Steatosis was classified as S1 (significant steatosis) with CAP > 238 dB/m, S2 with CAP > 260 dB/m, and S3 with CAP > 292 dB/m. Multivariable logistic regression analyses were performed to assess the factors associated with HS in this cohort.Significant HS was detected in 118 monoinfected patients (149 in the total cohort). In the total cohort as well as in the monoinfected patients alone, HS grade distribution showed a similar pattern (S1:29%, S2:34%, and S3:37%). Interestingly, patients with HS had a longer history of HIV infection and combined antiretroviral therapy (cART). Interalia, age, gender, ethnicity, and metabolic factors were strongly associated with HS, while body mass index (BMI), triglyceride, and glycated hemoglobin (HbA1c) levels were independently associated with significant HS.HS is highly prevalent among HIV monoinfected patients. Although metabolic risk factors, such as obesity and poorly controlled diabetes, are independently associated with HS in HIV monoinfected patients, cART and control of HIV seem to play an indirect role in the development of HS, probably through the return-to-health effect.

Impact of circulating bacterial DNA in long-term glucose homeostasis in non-diabetic patients with HIV infection: cohort study

In HIV-infected patients, the damage in the gut mucosal immune system is not completely restored after antiretroviral therapy (ART). It results in microbial translocation, which could influence the immune and inflammatory response. We aimed at investigating the long-term impact of bacterial-DNA translocation (bactDNA) on glucose homeostasis in an HIV population. This was a cohort study in HIV-infected patients whereby inclusion criteria were: patients with age >18 years, ART-naïve or on effective ART (<50 HIV-1 RNA copies/mL) and without diabetes or chronic hepatitis C. Primary outcome was the change in HbA1c (%). Explanatory variables at baseline were: bactDNA (qualitatively detected in blood samples by PCR [broad-range PCR] and gene 16SrRNA - prokaryote), ART exposure, HOMA-R and a dynamic test HOMA-CIGMA [continuous infusion of glucose with model assessment], hepatic steatosis (hepatic triglyceride content - 1H-MRS), visceral fat / subcutaneous ratio and inflammatory markers. Fifty-four men (age 43.2 ± 8.3 years, BMI 24.9 ± 3 kg/m², mean duration of HIV infection of 8.1 ± 5.3 years) were included. Baseline HbA1c was 4.4 ± 0.4% and baseline presence of BactDNA in six patients. After 8.5 ± 0.5 years of follow-up, change in HbA1c was 1.5 ± 0.47% in patients with BactDNA vs 0.87 ± 0.3% in the rest of the sample p < 0.001. The change in Hba1c was also influenced by protease inhibitors exposure, but not by baseline indices of insulin resistance, body composition, hepatic steatosis, inflammatory markers or anthropometric changes. In non-diabetic patients with HIV infection, baseline bacterial translocation and PI exposure time were the only factors associated with long-term impaired glucose homeostasis.

The Ca2+/CaMKK2 axis mediates the telbivudine induced upregulation of creatine kinase: Implications for mechanism of antiviral nucleoside analogs' side effect

Telbivudine (LdT), a widely prescribed anti-hepatitis B virus (HBV) drug for the treatment of chronic Hepatitis B (CHB), causes adverse reactions ranging from creatine kinase (CK) elevation to myopathy. The purpose of this study was to explore the mechanism(s) of LdT induced CK elevation. The effects of LdT on mitochondrial morphology and proteins (TK2 and β-actin), oxidative stress, intracellular Ca²⁺ levels, Ca²⁺-related signaling pathway (CaMKK2/AMPK), and Ca²⁺-related biomarkers such as superoxide dismutase (SOD) and malondialdehyde (MDA) were assessed in human skeletal muscle cells (HSKMCs). The results showed that LdT induced a dose-dependent increase in CK activity in HSKMCs, without affecting mitochondrial morphology, and TK2 and β-actin protein levels, following 72 h of treatment. In addition, LdT increased Ca²⁺ production, ROS generation, MDA and lipid peroxide (LPO) levels, and activated the CaMKK2/AMPK signaling pathway. Moreover, these effects were attenuated by the BAPIA-AM (the calcium chelator). We also confirmed the presence of relevant markers (MDA, LPO, and SOD) in serum from CHB patients after LdT treatment, and found that CK was positively correlated with MDA and LPO, and negatively associated with SOD. These findings indicate that LdT induces CK elevation and oxidative stress associated with imbalance of intracellular Ca²⁺ in HSKMCs, suggesting that Ca²⁺/CaMKK2 axis imbalance may underlie human LdT-induced CK elevation. The present findings provide a solid basis for assessing the mechanism of drug-induced CK elevation, which can help develop new tools for the prevention and treatment of diseases associated with drug-induced CK elevation.

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.

Changes in liver steatosis evaluated by transient elastography with the controlled attenuation parameter in HIV-infected patients

OBJECTIVES

There are scant data on the progression of hepatic steatosis (HS) in HIV infection. We therefore evaluated changes in HS over time in HIV-infected patients using the controlled attenuation parameter (CAP).

METHODS

A prospective cohort of 326 HIV-infected patients was included in this study. All patients underwent a CAP measurement. Changes in steatosis were evaluated by calculating the median (Q1-Q3) difference between baseline and 12-month CAP values.

RESULTS

The median (Q1-Q3) CAP was 221 (196-252) dB/m at baseline and 224 (198-257) dB/m at the 12-month visit (P = 0.617). Significant steatosis, that is, CAP ≥ 238 dB/m, was observed in 76 individuals (37%) at baseline and in 80 (39%) at the 12-month visit (P = 0.683). The following variables were associated with ΔCAP: plasma HIV RNA [< 50 vs. ≥ 50 HIV-1 RNA copies/mL: median (Q1-Q3) ΔCAP, 4 (-21, 27) vs. -21 (-49, 4) dB/m, respectively; P = 0.024]; body mass index (BMI) [no increase vs. increase: -13 (-40, 4) vs. 14 (-6, 32) dB/m, respectively; P < 0.001]; triglycerides [no increase vs. increase: -1 (-30, 22) vs. 15 (-3, 40) dB/m, respectively; P = 0.001]; fasting plasma glucose [not impaired vs. impaired: -4 (-31, 16) vs. 30 (15, 49) dB/m, respectively; P < 0.001]; and raltegravir [no vs. yes: 5 (-20, 29) vs. -11 (-37.5, 15) dB/m, respectively; P = 0.018]. The only factor independently associated with ΔCAP was BMI [B (standard error): 9.03 (1.9); P < 0.001].

CONCLUSIONS

Increases in CAP values over a period of 12 months in HIV-infected patients were strongly associated with elevations in BMI. Other metabolic factors and antiretroviral drugs were not predictors of CAP changes independent of BMI.

Distinct Mitochondrial Disturbance in CD4+T and CD8+T Cells From HIV-Infected Patients

BACKGROUND

Mitochondrial dysfunction has frequently been found in HIV-infected patients regardless of whether they received antiretroviral therapy (ART). Accumulating evidence suggests that HIV-infected patients exhibit marked changes in mitochondrial membrane potential (MMP), reactive oxygen species (ROS) accumulation, adenosine triphosphate generation, mitochondrial mass (MM), mitochondrial DNA, etc. However, mitochondrial toxicity in CD4T and CD8T cells caused by different levels of HIV progression and ART is poorly understood.

METHODS

Blood samples were obtained from 97 ART-naïve HIV-infected patients with different CD4T cell counts, 97 nucleoside-reverse transcriptase inhibitors-exposed HIV-infected patients, and 25 HIV-negative subjects. MMP, ROS, and MM in CD4T and CD8T cells were assessed by flow cytometry.

RESULTS

In healthy subjects, the levels of MMP and MM in CD4T cells were higher than those in CD8T cells. HIV infection led to an increase in MM in CD4T and CD8T cells, but mainly influenced MMP in CD8T cells and ROS accumulation in CD4T cells. MM in CD4T and CD8T cells gradually increased after the loss of CD4T cells. Although the dynamic changes in MMP in CD4T cells were different from those in CD8T cells during highly active ART, MM in both CD4T and CD8T cells was significantly decreased after 2 years of therapy, but increased again after 3 years.

CONCLUSIONS

HIV infection and antiretroviral therapy both led to mitochondrial disturbances in CD4T cells and CD8T cells; however, the abnormal changes in mitochondrial parameters in CD4+T cells were different from those in CD8T cells caused by HIV infection and antiretroviral therapy.

The Use of Cytochrome C Oxidase Enzyme Activity and Immunohistochemistry in Defining Mitochondrial Injury in Kidney Disease

The renal biopsy is a dynamic way of looking at renal disease, and tubular elements are an important part of this analysis. The mitochondria in 20 renal biopsies were examined by immunohistochemical (electron transport chain enzyme: cytochrome C oxidase IV [COX IV]) and enzyme histochemical methods (COX), both by light and electron microscopy. The distal convoluted tubules and thick ascending limbs showed the greatest intensity in the COX immunostains and enzyme activity in controls. The degree of mitochondrial COX protein and enzyme activity diminished as the tubules became atrophic. With proximal hypertrophic changes, there was great variation in both COX activity and protein expression. In contrast, in three cases of systemic lupus erythematosus, biopsied for high-grade proteinuria, the activity was consistently upregulated, whereas protein expression remained normal. These unexpected findings of heterogeneous upregulation in hypertrophy and the dyssynchrony of protein expression and activity may indicate mitochondrial dysregulation. Functional electron microscopy showed COX activity delineated by the intense mitochondrial staining in normal or hypertrophic proximal tubules. With atrophic changes, residual small mitochondria with diminished activity could be seen. With mitochondrial size abnormalities (enlargement and irregularity, adefovir toxicity), activity persisted. In the renal biopsy, mitochondrial analysis is feasible utilizing immunohistochemical and enzyme histochemical techniques.

HIV infection does not prevent the metabolic benefits of diet-induced weight loss in women with obesity

OBJECTIVE

To test the hypothesis that HIV infection impairs the beneficial effects of weight loss on insulin sensitivity, adipose tissue inflammation, and endoplasmic reticulum (ER) stress.

METHODS

A prospective clinical trial evaluated the effects of moderate diet-induced weight loss on body composition, metabolic function, and adipose tissue biology in women with obesity who were HIV-seronegative (HIV-) or HIV-positive (HIV+). Body composition, multiorgan insulin sensitivity (assessed by using a two-stage hyperinsulinemic-euglycemic clamp procedure with stable isotopically labeled tracer infusions), and adipose tissue expression of markers of inflammation, autophagy, and ER stress were evaluated in 8 HIV- and 20 HIV+ women with obesity before and after diet-induced weight loss of 6% to 8%.

RESULTS

Although weight loss was not different between groups (∼7.5%), the decrease in fat-free mass was greater in HIV+ than HIV- subjects (-4.4 ± 0.7% vs. -1.7 ± 1.0%, P < 0.05). Weight loss improved insulin sensitivity in adipose tissue (suppression of palmitate rate of appearance [Ra]), liver (suppression of glucose Ra), and muscle (glucose disposal) similarly in both groups. Weight loss did not affect adipose tissue expression of markers of inflammation or ER stress in either group.

CONCLUSIONS

Moderate diet-induced weight loss improves multiorgan insulin sensitivity in HIV+ women to the same extent as women who are HIV-. However, weight loss causes a greater decline in fat-free mass in HIV+ than HIV- women.

Tenofovir alafenamide (TAF) does not deplete mitochondrial DNA in human T-cell lines at intracellular concentrations exceeding clinically relevant drug exposures

HIV-infected patients treated with certain nucleoside reverse transcriptase inhibitors (NRTIs) have experienced adverse effects due to drug-related mitochondrial toxicity. Tenofovir alafenamide (TAF) is a novel prodrug of the NRTI tenofovir (TFV) with an improved safety profile compared to tenofovir disoproxil fumarate (TDF). Prior in vitro studies have demonstrated that the parent nucleotide TFV has no significant effects on mtDNA synthesis. This study investigated whether clinically relevant TAF and TDF exposures affect mtDNA content in human lymphocytes. First, activated or resting peripheral blood mononuclear cells (PBMCs), as well as MT-2 and Jurkat T-cell lines, were continuously treated with ddC for 10 days to establish their susceptibility to mtDNA depletion. PBMCs had low sensitivity to NRTI-mediated mtDNA depletion in vitro. In contrast, ddC treatment of rapidly dividing MT-2 and Jurkat cells resulted in a dose-dependent decrease in mtDNA. Therefore, these two T-cell lines were selected for evaluating TAF and TDF treatment effects. MT-2 and Jurkat cells were pulse-treated with TAF or TDF every 24 h for 10 days to mimic pharmacologically relevant drug exposures. Pulse treatment of cells with 3.3 μM TAF or 1.1 μM TDF for 10 days resulted in 2- to 7-fold greater steady-state intracellular TFV-diphosphate (TFV-DP) levels than those observed clinically in TAF- or TDF-treated patients. At these concentrations, no significant TAF- (106.7% and 84.1% of control; p = 0.77 and 0.12 for MT-2 and Jurkat, respectively) or TDF- (100.6% and 91.0% of control; p = 0.91 and 0.37, respectively) associated reduction in mtDNA content was observed compared with untreated control cells. This study demonstrates that, despite delivering higher intracellular levels of TFV-DP than TDF, TAF does not inhibit mtDNA synthesis in vitro at concentrations exceeding the clinically relevant intracellular drug exposures. Thus, TAF has a low potential for mitochondrial toxicity in T-cells of HIV-infected patients.

Editor's Highlight: Comparative Renal Safety Assessment of the Hepatitis B Drugs, Adefovir, Tenofovir, Telbivudine and Entecavir in Rats

The aim of this study was to determine the relative safety of 4 antiviral drugs (telbivudine, tenofovir, adefovir, and entecavir) against hepatitis B virus with respect to kidney function and toxicity in male Sprague Dawley rats. The antiviral drugs were administered once daily for 4 weeks by oral gavage at ∼10 and 25-40 times the human equivalent dose. Main assessments included markers of renal toxicity in urine, magnetic resonance imaging (MRI) of kidney function, histopathology, and electron microscopic examination. Administration of adefovir at 11 and 28 mg/kg for 4 weeks caused functional and morphological kidney alterations in a time- and dose-dependent manner, affecting mainly the proximal tubules and suggesting a mechanism of toxicity related to mitochondrial degeneration/depletion. Of note, the observed adefovir-induced reduction of kidney function was not detected by the standard method of glomerular filtration rate (GFR) measurements (clearance rate of the endogenous marker, creatinine), thereby emphasizing the superiority of MRI in terms of sensitive detection of GFR in rats. For the low dose of 300 mg/kg of tenofovir, minor kidney effects such as nuclear enlargement in the tubular epithelium, and hyaline droplets accumulation were detected, which was also observed for the low dose (11 mg/kg) of adefovir. No assessments could be done at the higher dose of 600/1000 mg/kg tenofovir due to gastrointestinal tract toxicity which prevented treatment of the animals for longer than 1 week. Entecavir at 1 and 3 mg/kg and telbivudine at 600 and 1600 mg/kg caused no toxicologically relevant effects on the kidney.

Metabolic Complications and Glucose Metabolism in HIV Infection: A Review of the Evidence

HIV infection and antiretroviral therapy (ART) use are associated with perturbations in glucose and lipid metabolism. Increasing incidence of diabetes, cardiovascular disease, and obesity highlights the need for early identification and treatment of metabolic dysfunction. Newer ART regimens are less toxic for cellular function and metabolism but have failed to completely eliminate metabolic dysfunction with HIV infection. Additional factors, including viral-host interactions, diet, physical activity, non-ART medications, and aging may further contribute to metabolic disease risk in the HIV setting. We summarize the recent literature regarding the impact on metabolic function of HIV infection, ART, and pharmaceutical or lifestyle prescriptions.

Analysis of the Endogenous Deoxynucleoside Triphosphate Pool in HIV-Positive and -Negative Individuals Receiving Tenofovir-Emtricitabine

Tenofovir (TFV) disoproxil fumarate (TDF) and emtricitabine (FTC), two nucleos(t)ide analogs (NA), are coformulated as an anti-HIV combination tablet for treatment and preexposure prophylaxis (PrEP). TDF/FTC may have effects on the deoxynucleoside triphosphate (dNTP) pool due to their similar structures and similar metabolic pathways. We carried out a comprehensive clinical study to characterize the effects of TDF/FTC on the endogenous dNTP pool, from baseline to 30 days of TDF/FTC therapy, in both treatment-naive HIV-positive and HIV-negative individuals. dATP, dCTP, dGTP, and TTP were quantified in peripheral blood mononuclear cells (PBMC) with a validated liquid chromatography-tandem mass spectrometry (LC-MS/MS) methodology. Forty individuals (19 HIV-positive) were enrolled and underwent a baseline visit and then received TDF/FTC for at least 30 days. Longitudinal measurements were analyzed using mixed-model segmented linear regression analysis. The dNTPs were reduced by 14% to 37% relative to the baseline level within 3 days in both HIV-negative and HIV-positive individuals (P ≤ 0.003). These reductions persisted to various degrees at day 30. These findings indicate that dNTP pools are influenced by TDF/FTC therapy. This may alter cellular homeostasis and could increase the antiviral effect through a more favorable analog/dNTP ratio. Further work is needed to elucidate mechanisms, to evaluate the clinical significance of these findings, and to further probe differences between HIV-negative and HIV-positive individuals. (This study has been registered at ClinicalTrials.gov under identifier NCT01040091.).

Effects of BMS-986094, a Guanosine Nucleotide Analogue, on Mitochondrial DNA Synthesis and Function

BMS-986094, the prodrug of a guanosine nucleotide analogue (2'-C-methylguanosine), was withdrawn from clinical trials due to serious safety issues. Nonclinical investigative studies were conducted as a follow up to evaluate the potential for BMS-986094-related mitochondrial-toxicity. In vitro, BMS-986094 was applied to human hepatoma cells (HepG2 and Huh-7) or cardiomyocytes (hiPSCM) up to 19 days to assess mitochondrial DNA content and specific gene expression. There were no mitochondrial DNA changes at concentrations ≤10 µM. Transcriptional effects, such as reductions in Huh-7 MT-ND1 and MT-ND5 mRNA content and hiPSCM MT-ND1, MT-COXII, and POLRMT protein expression levels, occurred only at cytotoxic concentrations (≥10 µM) suggesting these transcriptional effects were a consequence of the observed toxicity. Additionally, BMS-986094 has a selective weak affinity for inhibition of RNA polymerases as opposed to DNA polymerases. In vivo, BMS-986094 was given orally to cynomolgus monkeys for 3 weeks or 1 month at doses of 15 or 30 mg/kg/day. Samples of heart and kidney were collected for assessment of mitochondrial respiration, mitochondrial DNA content, and levels of high energy substrates. Although pronounced cardiac and renal toxicities were observed in some monkeys at 30 mg/kg/day treated for 3-4 weeks, there were no changes in mitochondrial DNA content or ATP/GTP levels. Collectively, these data suggest that BMS-986094 is not a direct mitochondrial toxicant.

Identification of transformation products of antiviral drugs formed during biological wastewater treatment and their occurrence in the urban water cycle

The fate of five antiviral drugs (abacavir, emtricitabine, ganciclovir, lamivudine and zidovudine) was investigated in biological wastewater treatment. Investigations of degradation kinetics were accompanied by the elucidation of formed transformation products (TPs) using activated sludge lab experiments and subsequent LC-HRMS analysis. Degradation rate constants ranged between 0.46 L d(-1) gSS(-1) (zidovudine) and 55.8 L d(-1) gSS(-1) (abacavir). Despite these differences of the degradation kinetics, the same main biotransformation reaction was observed for all five compounds: oxidation of the terminal hydroxyl-moiety to the corresponding carboxylic acid (formation of carboxy-TPs). In addition, the oxidation of thioether moieties to sulfoxides was observed for emtricitabine and lamivudine. Antiviral drugs were detected in influents of municipal wastewater treatment plants (WWTPs) with concentrations up to 980 ng L(-1) (emtricitabine), while in WWTP effluents mainly the TPs were found with concentration levels up to 1320 ng L(-1) (carboxy-abacavir). Except of zidovudine none of the original antiviral drugs were detected in German rivers and streams, whereas the concentrations of the TPs ranged from 16 ng L(-1) for carboxy-lamivudine up to 750 ng L(-1) for carboxy-acyclovir. These concentrations indicate an appreciable portion from WWTP effluents present in rivers and streams, as well as the high environmental persistence of the carboxy-TPs. As a result three of the carboxylic TPs were detected in finished drinking water.

Lon protease and eiF2α are involved in acute, but not prolonged, antiretroviral induced stress response in HepG2 cells

Lon protease, an ATP dependent mitochondrial protease, is important in mitochondrial protein maintenance. Disruption of protein homeostasis and mitochondrial dysfunction is associated with lipodystrophy, metabolic syndrome and accelerated aging, and are commonly observed in patients on long term antiretroviral therapy. Sirtuin 3 (SIRT3) is a post-translational regulator of Lon and regulates antioxidant response. We previously showed the nucleoside analogues (NRTIs), Zidovudine (AZT; 7.1 μM), Stavudine (d4T; 4 μM), and Tenofovir (TFV; 1.2 μM) induced oxidative stress and mitochondrial dysfunction in human hepatoma (HepG2) cells at 24 h (h) and 120 h. We conducted a mitochondrial proteomic assessment of homeostasis in the same model, using the same NRTIs. Protein expression of Lon, SIRT3, heat shock protein (HSP) 60, phospho-eukaryotic translation initiation factor 2α (p-eIF2α; Ser51) and phospho-c-jun N-terminal kinase (p-JNK; Thr183/Tyr185) were quantified by western blots. The data showed all stress responses were significantly increased in HepG2 cells by all antiretroviral drugs at 24 h (p < 0.0001); however, at 120 h, a significant depletion in the ATP-dependent proteins Lon (p = 0.00013) and HSP60 (p < 0.0001) was observed. Proteins initiated by endoplasmic reticulum stress: p-eIF2α (p = 0.001) and p-JNK (p = 0.0029), were significantly reduced following prolonged treatment. SIRT3 was maintained at elevated levels in the treated cells following prolonged exposure (p < 0.001). We conclude that the ATP dependent proteins are more relevant to acute toxicity, while SIRT3 confers protection over prolonged periods of toxicity.

Lactic acidosis in patients with hepatitis C virus cirrhosis and combined ribavirin/sofosbuvir treatment

BACKGROUND & AIMS

Sofosbuvir (SOF) based interferon-alfa free antiviral therapy has become the treatment of choice for patients with chronic hepatitis C virus (HCV) infection. Little is known about safety of drug combinations using two nucleos(t)ide polymerase inhibitors in patients with HCV associated advanced cirrhosis. Here, we report frequent occurrence of lactic acidosis associated with acute-on-chronic hepatic decompensation during ribavirin (RBV) plus SOF based antiviral therapy.

METHODS

Thirty-five patients with chronic hepatitis C and advanced fibrosis, compensated cirrhosis, and decompensated cirrhosis without and after liver transplantation were treated with SOF based antiviral therapy with and without RBV. Adverse events including lactic acidosis (pH <7.35, lactate >20 mg/dl) were recorded 24 weeks before and during (mean ±SD, 18±11 weeks) antiviral therapy. Efficacy was determined by assessment of serum HCV RNA.

RESULTS

We observed severe adverse events in 15/35 (43%) patients before (24 weeks) and in 12/35 (34%) patients during antiviral therapy, the majority in association with acute-on-chronic hepatic decompensation. Lactic acidosis occurred in 5/35 (14%) patients during therapy, while no event of lactic acidosis was observed prior to therapy. Lactic acidosis was associated with hepatic decompensation including renal failure and infection, and was severe (pH <7.3) in two patients.

CONCLUSIONS

RBV in combination with SOF based antiviral therapy in patients with HCV associated advanced cirrhosis may be associated with the development of lactic acidosis. Impaired renal function, and higher MELD/Child-Pugh scores were identified as potential risk factors.

The purine analogues abacavir and didanosine increase acetaminophen-induced hepatotoxicity by enhancing mitochondrial dysfunction

BACKGROUND

NRTIs are essential components of HIV therapy with well-documented, long-term mitochondrial toxicity in hepatic cells, but whose acute effects on mitochondria are unclear. As acetaminophen-induced hepatotoxicity also involves mitochondrial interference, we hypothesized that it would be exacerbated in the context of ART.

METHODS

We evaluated the acute effects of clinically relevant concentrations of the most widely used NRTIs, alone or combined with acetaminophen, on mitochondrial function and cellular viability.

RESULTS

The purine analogues abacavir and didanosine produced an immediate and concentration-dependent inhibition of oxygen consumption and complex I and III activity. This inhibition was accompanied by an undermining of mitochondrial function, with increased production of reactive oxygen species and reduction of mitochondrial membrane potential and intracellular ATP levels. However, this interference did not compromise cell survival. Co-administration with concentrations of acetaminophen below those considered hepatotoxic exacerbated the deleterious effects of both compounds on mitochondrial function and compromised cellular viability, showing a clear correlation with diminished glutathione levels.

CONCLUSIONS

The simultaneous presence of purine analogues and low concentrations of acetaminophen significantly potentiates mitochondrial dysfunction, increasing the risk of liver injury. This new mechanism is relevant given the liver's susceptibility to mitochondrial dysfunction-related toxicity and the tendency of the HIV infection to increase oxidative stress.

Inverse association between microRNA-124a and ABCC4 in HepG2 cells treated with antiretroviral drugs

The ATP-binding cassette (ABC) super-family of drug transporters regulates efflux of xenobiotic compounds. The subfamily, multi-drug resistance proteins (MRPs) transports cyclic nucleotides and xenobiotics. Epigenetic modulation of drug transporters is scarcely described. The regulatory role of microRNA (miR)-124a on drug transporter gene ABCC4 was only recently reported. Our study investigated the differential regulation of miR-124a by nucleoside reverse transcriptase inhibitors (NRTIs): Zidovudine (AZT), Stavudine (d4T) and Tenofovir (TFV); at 24 h and 120 h treatments in HepG2 cells. ABCC4 mRNA (qPCR) and ABCC4 protein (western blot) were quantified. Cytotoxicity was evaluated by lactate dehydrogenase (LDH) levels. All NRTIs elevated miR-124a levels at 24 h, with a concomitant decline in ABCC4 mRNA levels (p<0.05). At 120 h, d4T and TFV elevated miR-124a and depleted ABCC4 mRNA levels (p<0.0001), while the inverse was observed with AZT (p<0.005). ABCC4 protein was increased by d4T and TFV at 24h. A significant reduction in protein levels was observed at 120 h in all three treatments (p<0.005). The disjoint in mRNA and protein levels is likely due to ABCC4 being a membrane bound protein. Following prolonged exposure, membrane integrity was compromised as evidenced by increased LDH leakage (p<0.005). We conclude antiretroviral drugs have varying effects on miR-124a and ABCC4.

Effect of Cumulating Exposure to Abacavir on the Risk of Cardiovascular Disease Events in Patients From the Swiss HIV Cohort Study

BACKGROUND

Patients with HIV exposed to the antiretroviral drug abacavir may have an increased risk of cardiovascular disease (CVD). There is concern that this association arises because of a channeling bias. Even if exposure is a risk, it is not clear how that risk changes as exposure cumulates.

METHODS

We assess the effect of exposure to abacavir on the risk of CVD events in the Swiss HIV Cohort Study. We use a new marginal structural Cox model to estimate the effect of abacavir as a flexible function of past exposures while accounting for risk factors that potentially lie on a causal pathway between exposure to abacavir and CVD.

RESULTS

A total of 11,856 patients were followed for a median of 6.6 years; 365 patients had a CVD event (4.6 events per 1000 patient-years). In a conventional Cox model, recent--but not cumulative--exposure to abacavir increased the risk of a CVD event. In the new marginal structural Cox model, continued exposure to abacavir during the past 4 years increased the risk of a CVD event (hazard ratio = 2.06; 95% confidence interval: 1.43 to 2.98). The estimated function for the effect of past exposures suggests that exposure during the past 6-36 months caused the greatest increase in risk.

CONCLUSIONS

Abacavir increases the risk of a CVD event: the effect of exposure is not immediate, rather the risk increases as exposure cumulates over the past few years. This gradual increase in risk is not consistent with a rapidly acting mechanism, such as acute inflammation.

Mitochondrial DNA mutations in ageing and disease: implications for HIV?

Mitochondrial DNA (mtDNA) mutations cause neurological and multisystem disease. Somatic (acquired) mtDNA mutations are also associated with degenerative diseases and with normal human ageing. It is well established that certain nucleoside reverse transcriptase inhibitor (NRTI) antiretroviral drugs cause inhibition of the mtDNA polymerase, pol γ, leading to a reduction in mtDNA content (depletion). Given this effect of NRTI therapy on mtDNA replication, it is plausible that NRTI treatment may also lead to increased mtDNA mutations. Here we review recent evidence for an effect of HIV infection or NRTI therapy on mtDNA mutations, as well as discussing the methodological challenges in addressing this question. Finally, we discuss the possible implications for HIV-infected persons, with particular reference to ageing.

Antiretroviral nucleoside analogues suppress antibody synthesis in human B-lymphocytes

BACKGROUND

Some antiretroviral nucleoside reverse transcriptase inhibitors (NRTI) impair mitochondrial polymerase-γ and T-cell proliferation, possibly by pyrimidine depletion. We aimed to analyse NRTI effects on the content of mitochondrial DNA (mtDNA) and B-cells, and on their proliferation and antibody synthesis.

METHODS

Peripheral blood B-lymphocytes from six healthy individuals were stimulated in vitro with interleukin-4 and Staphylococcus aureus superantigen in the presence or absence of NRTI in concentrations equivalent to, or fivefold exceeding, human peak plasma levels. We also tested the effects of uridine, a pyrimidine precursor, which has antagonized NRTI toxicities in other models.

RESULTS

During 9 days of culture, B-lymphocyte proliferation and vitality were not affected by NRTI. Didanosine and stavudine, but not zidovudine, dose-dependently induced mtDNA depletion. All three NRTI significantly and dose-dependently impaired the synthesis of all immunoglobulin classes. The lymphocytotoxic effects of the thymidine analogues zidovudine and stavudine on B-lymphocytes were antagonized by the addition of uridine.

CONCLUSIONS

Didanosine, stavudine and zidovudine induce mitochondrial toxicity in human B-lymphocytes and impair the immunoglobulin synthesis in vitro, warranting further studies on their in vivo effects.

Mitochondrial toxicity in HIV type-1-exposed pregnancies in the era of highly active antiretroviral therapy

Background

The aim of this study was to determine the effects of HIV type-1 (HIV-1) infection and antiretroviral therapy (ART) on placental mitochondria.

Methods

HIV-1-infected pregnant women and HIV-1 -uninfected controls were enrolled prospectively. Placental mitochondrial DNA (mtDNA) copy numbers were determined by quantitative PCR, subunits II and IV of cytochrome c oxidase (COX) were quantified by western blot and mitochondrial ultrastructure was evaluated by electron microscopy. Venous blood lactate was measured in newborns.

Results

In total, 45 HIV-1-infected pregnant women on ART and 32 controls were included. Mean ±sd mtDNA copy numbers were significantly reduced in ART and HIV-1-exposed placentas (240 ±118 copies/ cell) in comparison with controls (686 ±842 copies/cell; P<0.001). The mean COX II/IV ratio was 48% lower in the investigational group compared with controls ( P<0.001). There was no evidence of severe ultrastructural damage within mitochondria of HIV-1-infected ART-exposed placentas. Although lactate levels between newborns did not differ, they were negatively correlated with placental mtDNA levels. There was no clear association between mitochondrial parameters and a particular nucleoside reverse transcriptase inhibitor (NRTI), the number of NRTIs or time of NRTI exposure.

Conclusions

Placental tissue of HIV-1-infected ART-exposed pregnancies shows evidence of mtDNA depletion with secondary respiratory chain compromise. The clinical effects of this finding warrant further investigation.