HIV treatment and associated mitochondrial pathology: review of 25 years of in vitro, animal, and human studies

Metabolic, Mitochondrial, and Inflammatory Effects of Efavirenz, Emtricitabine, and Tenofovir Disoproxil Fumarate in Asymptomatic Antiretroviral-Naïve People with HIV

This study aimed to comprehensively assess the metabolic, mitochondrial, and inflammatory effects of first-line efavirenz, emtricitabine, and tenofovir disoproxil fumarate (EFV/FTC/TDF) single-tablet regimen (STR) relative to untreated asymptomatic HIV infection. To this end, we analyzed 29 people with HIV (PWH) treated for at least one year with this regimen vs. 33 antiretroviral-naïve PWH. Excellent therapeutic activity was accompanied by significant alterations in metabolic parameters. The treatment group showed increased plasmatic levels of glucose, total cholesterol and its fractions (LDL and HDL), triglycerides, and hepatic enzymes (GGT, ALP); conversely, bilirubin levels (total and indirect fraction) decreased in the treated cohort. Mitochondrial performance was preserved overall and treatment administration even promoted the recovery of mitochondrial DNA (mtDNA) content depleted by the virus, although this was not accompanied by the recovery in some of their encoded proteins (since cytochrome c oxidase II was significantly decreased). Inflammatory profile (TNFα, IL-6), ameliorated after treatment in accordance with viral reduction and the recovery of TNFα levels correlated to mtDNA cell restoration. Thus, although this regimen causes subclinical metabolic alterations, its antiviral and anti-inflammatory properties may be associated with partial improvement in mitochondrial function.

Connection Between HIV and Mitochondria in Cardiovascular Disease and Implications for Treatments

HIV infection and antiretroviral therapy alter mitochondrial function, which can progressively lead to mitochondrial damage and accelerated aging. The interaction between persistent HIV reservoirs and mitochondria may provide insight into the relatively high rates of cardiovascular disease and mortality in persons living with HIV. In this review, we explore the intricate relationship between HIV and mitochondrial function, highlighting the potential for novel therapeutic strategies in the context of cardiovascular diseases. We reflect on mitochondrial dynamics, mitochondrial DNA, and mitochondrial antiviral signaling protein in the context of HIV. Furthermore, we summarize how toxicities related to early antiretroviral therapy and current highly active antiretroviral therapy can contribute to mitochondrial dysregulation, chronic inflammation, and poor clinical outcomes. There is a need to understand the mechanisms and develop new targeted therapies. We further consider current and potential future therapies for HIV and their interplay with mitochondria. We reflect on the next-generation antiretroviral therapies and HIV cure due to the direct and indirect effects of HIV persistence, associated comorbidities, coinfections, and the advancement of interdisciplinary research fields. This includes exploring novel and creative approaches to target mitochondria for therapeutic intervention.

Lamivudine-based two-drug regimens with dolutegravir or protease inhibitor: Virological suppression in spite of previous therapy failure or renal dysfunction

BACKGROUND

Two-Drug Regimens (2DR) have proven effective in clinical trials but real-world data, especially in resource-limited settings, is limited.

OBJECTIVES

To evaluate viral suppression of lamivudine-based 2DR, with dolutegravir or ritonavir-boosted protease inhibitor (lopinavir/r, atazanavir/r or darunavir/r), among all cases regardless of selection criteria.

PATIENTS AND METHODS

A retrospective study, conducted in an HIV clinic in the metropolitan area of São Paulo, Brazil. Per-protocol failure was defined as viremia above 200 copies/mL at outcome. Intention-To-Treat-Exposed (ITT-E) failure was considered for those who initiated 2DR but subsequently had either (i) Delay over 30 days in Antiretroviral Treatment (ART) dispensation, (ii) ART changed or (iii) Viremia > 200 copies/mL in the last observation using 2DR.

RESULTS

Out of 278 patients initiating 2DR, 99.6% had viremia below 200 copies/mL at last observation, 97.8% below 50 copies/mL. Lamivudine resistance, either documented (M184V) or presumed (viremia > 200 copies/mL over a month using 3TC) was present in 11% of cases that showed lower suppression rates (97%), but with no significant hazard ratio to fail per ITT-E (1.24, p = 0.78). Decreased kidney function, present in 18 cases, showed of 4.69 hazard ratio (p = 0.02) per ITT-E for failure (3/18). As per protocol analysis, three failures occurred, none with renal dysfunction.

CONCLUSIONS

The 2DR is feasible, with robust suppression rates, even when 3TC resistance or renal dysfunction is present, and close monitoring of these cases may guarantee long-term suppression.

Dolutegravir-containing HIV therapy reversibly alters mitochondrial health and morphology in cultured human fibroblasts and peripheral blood mononuclear cells

OBJECTIVES

Given the success of combination antiretroviral therapy (cART) in treating HIV viremia, drug toxicity remains an area of interest in HIV research. Despite newer integrase strand transfer inhibitors (InSTIs), such as dolutegravir (DTG) and raltegravir (RAL), having excellent clinical tolerance, there is emerging evidence of off-target effects and toxicities. Although limited in number, recent reports have highlighted the vulnerability of mitochondria to these toxicities. The aim of the present study is to quantify changes in cellular and mitochondrial health following exposure to current cART regimens at pharmacological concentrations. A secondary objective is to determine whether any cART-associated toxicities would be modulated by human telomerase reverse transcriptase (hTERT).

METHODS

We longitudinally evaluated markers of cellular (cell count, apoptosis), and mitochondrial health [mitochondrial reactive oxygen species (mtROS), membrane potential (MMP) and mass (mtMass)] by flow cytometry in WI-38 human fibroblast with differing hTERT expression/localization and peripheral blood mononuclear cells. This was done after 9 days of exposure to, and 6 days following the removal of, seven current cART regimens, including three that contained DTG. Mitochondrial morphology was assessed by florescence microscopy and quantified using a recently developed deep learning-based pipeline.

RESULTS

Exposure to DTG-containing regimens increased apoptosis, mtROS, mtMass, induced fragmented mitochondrial networks compared with non-DTG-containing regimens, including a RAL-based combination. These effects were unmodulated by telomerase expression. All effects were fully reversible following removal of drug pressure.

CONCLUSION

Taken together, our observations indicate that DTG-containing regimens negatively impact cellular and mitochondrial health and may be more toxic to mitochondria, even among the generally well tolerated InSTI-based cART.

Functional characteristics of 3'-azido-3'-deoxythymidine transport at the blood-testis barrier

3'-Azido-3'-deoxythymidine (AZT), an antiretroviral drug, is often adopted in the therapy for human immunodeficiency virus (HIV) infection, and the characteristics of AZT transport at the blood-testis barrier (BTB) were investigated in this study. In the integration plot analysis that evaluates the transport activity in vivo, the apparent influx clearance of [³H]AZT was significantly greater than that of [¹⁴C]D-mannitol, a non-permeable paracellular transport marker. In the uptake study in vitro with TM4 cells derived from mouse Sertoli cells, [³H]AZT uptake exhibited a time- and concentration-dependent manner, of which K_m and V_max values being 20.3 µM and 102 pmol/(min·mg protein), respectively. In the inhibition analysis, [³H]AZT uptake was not affected by extracellular inorganics and some substrates of transporters putatively involved in AZT transport. In the further inhibition analyses to elucidate the characteristics of AZT transport, [³H]AZT uptake was strongly reduced in the presence of several nucleosides, that are categorized as 2'-deoxynucleosides with pyrimidine, whereas little effect on [³H]AZT uptake was exhibited in the presence of other nucleosides, nucleobases, and antiretrovirals. These results suggest the influx transport of AZT from the circulating blood to the testis, and the involvement of carrier-mediated process at the BTB, which selectively recognizes 2'-deoxynucleosides with a pyrimidine base.

Pharmacokinetic and toxicodynamic concepts in idiosyncratic, drug-induced liver injury

INTRODUCTION

Idiosyncratic drug-induced liver injury (IDILI) causes morbidity and mortality in patients and leads to curtailed use of efficacious pharmaceuticals. Unlike intrinsically toxic reactions, which depend on dose, IDILI occurs in a minority of patients at therapeutic doses. Much remains unknown about causal links among drug exposure, a mode of action, and liver injury. Consequently, numerous hypotheses about IDILI pathogenesis have arisen.

AREAS COVERED

Pharmacokinetic and toxicodynamic characteristics underlying current hypotheses of IDILI etiology are discussed and illustrated graphically.

EXPERT OPINION

Hypotheses to explain IDILI etiology all involve alterations in pharmacokinetics, which lead to plasma drug concentrations that rise above a threshold for toxicity, or in toxicodynamics, which result in a lowering of the toxicity threshold. Altered pharmacokinetics arise, for example, from changes in drug metabolism or from transporter polymorphisms. A lowered toxicity threshold can arise from drug-induced mitochondrial injury, accumulation of toxic endogenous factors or harmful immune responses. Newly developed, interactive freeware (DemoTox-PK; https://bit.ly/DemoTox-PK) allows the user to visualize how such alterations might lead to a toxic reaction. The illustrations presented provide a framework for conceptualizing idiosyncratic reactions and could serve as a stimulus for future discussion, education, and research into modes of action of IDILI.

Inclusion body myositis and associated diseases: an argument for shared immune pathologies

Inclusion body myositis (IBM) is the most prevalent idiopathic inflammatory myopathy (IIM) affecting older adults. The pathogenic hallmark of IBM is chronic inflammation of skeletal muscle. At present, we do not classify IBM into different sub-entities, with the exception perhaps being the presence or absence of the anti-cN-1A-antibody. In contrast to other IIM, IBM is characterized by a chronic and progressive disease course. Here, we discuss the pathophysiological framework of IBM and highlight the seemingly prototypical situations where IBM occurs in the context of other diseases. In this context, understanding common immune pathways might provide insight into the pathogenesis of IBM. Indeed, IBM is associated with a distinct set of conditions, such as human immunodeficiency virus (HIV) or hepatitis C-two conditions associated with premature immune cell exhaustion. Further, the pathomorphology of IBM is reminiscent of other muscle diseases, notably HIV-associated myositis or granulomatous myositis. Distinct immune pathways are likely to drive these commonalities and senescence of the CD8+ T cell compartment is discussed as a possible mechanism of pathogenesis. Future effort directed at understanding the co-occurrence of IBM and associated diseases could prove valuable to better understand the enigmatic IBM pathophysiology.

HIV-1 Gag and Vpr impair the inflammasome activation and contribute to the establishment of chronic infection in human primary macrophages

The successful establishment of HIV-1 infection is related to inflammasome blocking or inactivation, which can result in the viral evasion of the immune responses and formation of reservoirs in several tissues. In this sense, we aimed to evaluate the viral and cellular mechanisms activated during HIV-1 infection in human primary macrophages that allow an effective viral replication in these cells. We found that resting HIV-1-infected macrophages, but not those activated in classical or alternative patterns, released IL-1β and other pro-inflammatory cytokines, and showed increased CXCL10 expression, without changes in the NLRP3, AIM2 or RIG-I inflammasome pathways. Also, similar levels of Casp-1, phosphorylated NF-κB (p65) and NLRP3 proteins were found in uninfected and HIV-1-infected macrophages. Likewise, no alterations were detected in ASC specks released in the culture supernatant after HIV-1 infection, suggesting that macrophages remain viable after infection. Using in silico prediction studies, we found that the HIV-1 proteins Gag and Vpr interact with several host proteins. Comparable levels of trans-LTB4 were found in the supernatants of uninfected and HIV-1-infected macrophages, whereas ROS production was impaired in infected cells, which was not reversed after the PMA stimulus. Immunofluorescence analysis showed structural alterations in the mitochondrial architecture and an increase of BIM in the cytoplasm of infected cells. Our data suggest that HIV-1 proteins Gag and Vpr, through interacting with cellular proteins in the early steps of infection, preclude the inflammasome activation and the development of effective immune responses, thus allowing the establishment of the infection.

Antiretroviral Therapy-Induced Dysregulation of Gene Expression and Lipid Metabolism in HIV+ Patients: Beneficial Role of Antioxidant Phytochemicals

Human immunodeficiency virus (HIV) infection has continued to be the subject of study since its discovery nearly 40 years ago. Significant advances in research and intake of antiretroviral therapy (ART) have slowed the progression and appearance of the disease symptoms and the incidence of concomitant diseases, which are the leading cause of death in HIV+ persons. However, the prolongation of ART is closely related to chronic degenerative diseases and pathologies caused by oxidative stress (OS) and alterations in lipid metabolism (increased cholesterol levels), both of which are conditions of ART. Therefore, recent research focuses on using natural therapies to diminish the effects of ART and HIV infection: regulating lipid metabolism and reducing OS status. The present review summarizes current information on OS and cholesterol metabolism in HIV+ persons and how the consumption of certain phytochemicals can modulate these. For this purpose, MEDLINE and SCOPUS databases were consulted to identify publications investigating HIV disease and natural therapies and their associated effects.

Are Physical Fitness and CRP Related to Framingham Risk Score in HIV+ Adults?

Background. People living with HIV (PLWH) have increased risk of cardiovascular disease (CVD). The Framingham Risk Score (FRS) predicts a 10-year CVD risk. Its relationships to physical fitness and C-reactive protein (CRP) are not well established. The current aim is to determine the links between FRS, physical fitness, and CRP in PLWH. Methods. Participants (n = 87) were assessed on multiple biomarkers. The FRS was calculated with the respective variables. Other variables that correlated significantly with FRS were entered into a regression equation to determine their relationship to FRS. Results. The FRS for men was more than twice that for women (12.8 vs 6.0, P < .001). Men were more fit than women, but most participants were not fit. Aerobic capacity was predictive of FRS in men, but not in women, and muscular strength was not predictive of FRS. Women had more than double the CRP compared with men (7.9 vs 3.5 mg/L, P < .01), and it was unrelated to FRS. Conclusions. In men, aerobic capacity was significantly predictive of FRS, but muscular strength and CRP were unrelated to FRS in both genders. These results do not conclusively demonstrate that physical fitness and CRP are related to FRS in PLWH.

Increased prevalence of clonal hematopoiesis of indeterminate potential amongst people living with HIV

People living with human immunodeficiency virus (PLWH) have significantly increased risk for cardiovascular disease in part due to inflammation and immune dysregulation. Clonal hematopoiesis of indeterminate potential (CHIP), the age-related acquisition and expansion of hematopoietic stem cells due to leukemogenic driver mutations, increases risk for both hematologic malignancy and coronary artery disease (CAD). Since increased inflammation is hypothesized to be both a cause and consequence of CHIP, we hypothesized that PLWH have a greater prevalence of CHIP. We searched for CHIP in multi-ethnic cases from the Swiss HIV Cohort Study (SHCS, n = 600) and controls from the Atherosclerosis Risk in the Communities study (ARIC, n = 8111) from blood DNA-derived exome sequences. We observed that HIV is associated with a twofold increase in CHIP prevalence, both in the whole study population and in a subset of 230 cases and 1002 matched controls selected by propensity matching to control for demographic imbalances (SHCS 7%, ARIC 3%, p = 0.005). We also observed that ASXL1 is the most commonly mutated CHIP-associated gene in PLWH. Our results suggest that CHIP may contribute to the excess cardiovascular risk observed in PLWH.

Drug-induced Fatty Liver Disease: Pathogenesis and Treatment

Metabolic dysfunction-associated fatty liver disease (commonly known as MAFLD) impacts global health in epidemic proportions, and the resulting morbidity, mortality and economic burden is enormous. While much attention has been given to metabolic syndrome and obesity as offending factors, a growing incidence of polypharmacy, especially in the elderly, has greatly increased the risk of drug-induced liver injury (DILI) in general, and drug-induced fatty liver disease (DIFLD) in particular. This review focuses on the contribution of DIFLD to DILI in terms of epidemiology, pathophysiology, the most common drugs associated with DIFLD, and treatment strategies.

Mitochondrial DNA haplogroups and domain-specific neurocognitive performance in adults with HIV

Neurocognitive (NC) impairment (NCI) is an important cause of morbidity in persons with HIV (PWH). In the high-energy environment of the central nervous system, mitochondria contribute to neuroinflammation and aging, which may ultimately drive the pathogenesis of neurodegenerative diseases. Mitochondrial DNA (mtDNA) haplogroups are associated with health outcomes in PWH. For example, we previously observed less global NCI in Hispanic ancestry PWH having mtDNA haplogroup B. Another study reported increased NCI among PWH having African subhaplogroup L2a. We therefore analyzed NC domains in relation to these haplogroups in CNS HIV Antiretroviral Therapy Effects Research (CHARTER), a multi-site observational neuro-HIV study. Haplogroups were assigned using mtDNA sequence in 1016 PWH. Outcomes were NCI, defined by domain deficit score and mean T-scores (TS) for seven NC domains. Ancestry-stratified analyses of NC performance included Wilcoxon rank sum, χ2, and Fisher's exact tests. Multivariable regression adjusted for NC comorbidity, antiretroviral therapy use, and nadir CD4+ T cells. Among 98 Hispanic ancestry PWH, executive function, learning, and recall performance were better with haplogroup B (N = 17) than other haplogroups. With adjustment for covariates, haplogroup B remained associated with better executive function (p = 0.04) and recall TS (p = 0.03). PWH with haplogroup B had fewer impaired domains than other haplogroups (p < 0.01). Subhaplogroup L2a (N = 89) was associated with greater NCI in learning, recall, and working memory among 478 PWH of African ancestry, and had more impaired domains than other subhaplogroups (p < 0.01). These findings may inform risk stratification for NCI and studies to define mechanisms by which mtDNA variation may influence NCI in PWH.

Physiologically Relevant Concentrations of Dolutegravir, Emtricitabine, and Efavirenz Induce Distinct Metabolic Alterations in HeLa Epithelial and BV2 Microglial Cells

Microglia, the resident brain phagocytes, likely play a key role in human immunodeficiency virus (HIV) infection of the central nervous system (CNS) and subsequent neuropathogenesis; however, the nature of the infection-induced changes that yield damaging CNS effects and the stimuli that provoke microglial activation remains elusive, especially in the current era of using antiretroviral (ARV) drugs for ARV therapy (ART). Altered microglial metabolism can modulate cellular functionality and pathogenicity in neurological disease. While HIV infection itself alters brain energy metabolism, the effect of ARV drugs, particularly those currently used in treatment, on metabolism is understudied. Dolutegravir (DTG) and emtricitabine (FTC) combination, together with tenofovir (TAF or TDF), is one of the recommended first line treatments for HIV. Despite the relatively good tolerability and safety profile of FTC, a nucleoside reverse transcriptase inhibitor, and DTG, an integrase inhibitor, adverse side effects have been reported and highlight a need to understand off-target effects of these medications. We hypothesized that similar to previous ART regimen drugs, DTG and FTC side effects involve mitochondrial dysfunction. To increase detection of ARV-induced mitochondrial effects, highly glycolytic HeLa epithelial cells were forced to rely on oxidative phosphorylation by substituting galactose for glucose in the growth media. We assessed ATP levels, resazurin oxidation-reduction (REDOX), and mitochondrial membrane potential following 24-hour exposure (to approximate effects of one dose equivalent) to DTG, FTC, and efavirenz (EFV, a known mitotoxic ARV drug). Further, since microglia support productive HIV infection, act as latent HIV cellular reservoirs, and when dysfunctional likely contribute to HIV-associated neurocognitive disorders, the experiments were repeated using BV2 microglial cells. In HeLa cells, FTC decreased mitochondrial REDOX activity, while DTG, similar to EFV, impaired both mitochondrial ATP generation and REDOX activity. In contrast to HeLa cells, DTG increased cellular ATP generation and mitochondrial REDOX activity in BV2 cells. Bioenergetic analysis revealed that DTG, FTC, and EFV elevated BV2 cell mitochondrial respiration. DTG and FTC exposure induced distinct mitochondrial functional changes in HeLa and BV2 cells. These findings suggest cell type-specific metabolic changes may contribute to the toxic side effects of these ARV drugs.

Liver Fibrosis during Antiretroviral Treatment in HIV-Infected Individuals. Truth or Tale?

After the introduction of antiretroviral treatment (ART) back in 1996, the lifespan of people living with HIV (PLWH) has been substantially increased, while the major causes of morbidity and mortality have switched from opportunistic infections and AIDS-related neoplasms to cardiovascular and liver diseases. HIV itself may lead to liver damage and subsequent liver fibrosis (LF) through multiple pathways. Apart from HIV, viral hepatitis, alcoholic and especially non-alcoholic liver diseases have been implicated in liver involvement among PLWH. Another well known cause of hepatotoxicity is ART, raising clinically significant concerns about LF in long-term treatment. In this review we present the existing data and analyze the association of LF with all ART drug classes. Published data derived from many studies are to some extent controversial and therefore remain inconclusive. Among all the antiretroviral drugs, nucleoside reverse transcriptase inhibitors, especially didanosine and zidovudine, seem to carry the greatest risk for LF, with integrase strand transfer inhibitors and entry inhibitors having minimal risk. Surprisingly, even though protease inhibitors often lead to insulin resistance, they do not seem to be associated with a significant risk of LF. In conclusion, most ART drugs are safe in long-term treatment and seldom lead to severe LF when no liver-related co-morbidities exist.

Long-term treated HIV infection is associated with platelet mitochondrial dysfunction

HIV infection and antiretroviral therapy have been linked to mitochondrial dysfunction. The role of platelet mitochondrial dysfunction in thrombosis, immunoregulation and age-related diseases is increasingly appreciated. Here, we studied platelet mitochondrial DNA content (mtDNA_pl) and mitochondrial function in people living with HIV (PLHIV) and related this to platelet function. In a cohort of 208 treated PLHIV and 56 uninfected controls, mtDNA_pl was quantified, as well as platelet activation, platelet agonist-induced reactivity and inflammation by circulating factors and flow cytometry. In a subgroup of participants, the metabolic activity of platelets was further studied by mitochondrial function tests and the Seahorse Flux Analyzer. PLHIV had significantly lower mtDNA_pl compared to controls (8.5 copies/platelet (IQR: 7.0–10.7) vs. 12.2 copies/platelet (IQR: 9.5–16.6); p < 0.001), also after correction for age, sex and BMI. Prior zidovudine-use (n = 46) was associated with a trend for lower mtDNA_pl. PLHIV also had reduced ex vivo platelet reactivity and mean platelet volume compared to controls. MtDNA_pl correlated positively with both platelet parameters and correlated negatively with inflammatory marker sCD163. Mitochondrial function tests in a subgroup of participants confirmed the presence of platelet mitochondrial respiration defects. Platelet mitochondrial function is disturbed in PLHIV, which may contribute to platelet dysfunction and subsequent complications. Interventions targeting the preservation of normal platelet mitochondrial function may ultimately prove beneficial for PLHIV.

Persistent T Cell Repertoire Perturbation and T Cell Activation in HIV After Long Term Treatment

Objective

In people living with HIV (PLHIV), we sought to test the hypothesis that long term anti-retroviral therapy restores the normal T cell repertoire, and investigate the functional relationship of residual repertoire abnormalities to persistent immune system dysregulation.

Methods

We conducted a case-control study in PLHIV and HIV-negative volunteers, of circulating T cell receptor repertoires and whole blood transcriptomes by RNA sequencing, complemented by metadata from routinely collected health care records.

Results

T cell receptor sequencing revealed persistent abnormalities in the clonal T cell repertoire of PLHIV, characterized by reduced repertoire diversity and oligoclonal T cell expansion correlated with elevated CD8 T cell counts. We found no evidence that these expansions were driven by cytomegalovirus or another common antigen. Increased frequency of long CDR3 sequences and reduced frequency of public sequences among the expanded clones implicated abnormal thymic selection as a contributing factor. These abnormalities in the repertoire correlated with systems level evidence of persistent T cell activation in genome-wide blood transcriptomes.

Conclusions

The diversity of T cell receptor repertoires in PLHIV on long term anti-retroviral therapy remains significantly depleted, and skewed by idiosyncratic clones, partly attributable to altered thymic output and associated with T cell mediated chronic immune activation. Further investigation of thymic function and the antigenic drivers of T cell clonal selection in PLHIV are critical to efforts to fully re-establish normal immune function.

Apoptosis of Hepatocytes: Relevance for HIV-Infected Patients under Treatment

Due to medical advances over the past few decades, human immunodeficiency virus (HIV) infection, once a devastatingly mortal pandemic, has become a manageable chronic condition. However, available antiretroviral treatments (cART) cannot fully restore immune health and, consequently, a number of inflammation-associated and/or immunodeficiency complications have manifested themselves in treated HIV-infected patients. Among these chronic, non-AIDS (acquired immune deficiency syndrome)-related conditions, liver disease is one of the deadliest, proving to be fatal for 15–17% of these individuals. Aside from the presence of liver-related comorbidities, including metabolic disturbances and co-infections, HIV itself and the adverse effects of cART are the main factors that contribute to hepatic cell injury, inflammation, and fibrosis. Among the molecular mechanisms that are activated in the liver during HIV infection, apoptotic cell death of hepatocytes stands out as a key pathogenic player. In this review, we will discuss the evidence and potential mechanisms involved in the apoptosis of hepatocytes induced by HIV, HIV-encoded proteins, or cART. Some antiretroviral drugs, especially the older generation, can induce apoptosis of hepatic cells, which occurs through a variety of mechanisms, such as mitochondrial dysfunction, increased production of reactive oxygen species (ROS), and induction of endoplasmic reticulum (ER) stress and unfolded protein response (UPR), all of which ultimately lead to caspase activation and cell death.

Therapeutic Options in Hereditary Optic Neuropathies

Options for the effective treatment of hereditary optic neuropathies have been a long time coming. The successful launch of the antioxidant idebenone for Leber's Hereditary Optic Neuropathy (LHON), followed by its introduction into clinical practice across Europe, was an important step forward. Nevertheless, other options, especially for a variety of mitochondrial optic neuropathies such as dominant optic atrophy (DOA), are needed, and a number of pharmaceutical agents, acting on different molecular pathways, are currently under development. These include gene therapy, which has reached Phase III development for LHON, but is expected to be  developed also for DOA, whilst most of the other agents (other antioxidants, anti-apoptotic drugs, activators of mitobiogenesis, etc.) are almost all at Phase II or at preclinical stage of research. Here, we review proposed target mechanisms, preclinical evidence, available clinical trials with primary endpoints and results, of a wide range of tested molecules, to give an overview of the field, also providing the landscape of future scenarios, including gene therapy, gene editing, and reproductive options to prevent transmission of mitochondrial DNA mutations.

Emerging prevalence of fatty liver disease in HIV

Fatty liver disease is a growing concern in people living with HIV, the main drivers are alcoholic liver disease and nonalcoholic fatty liver disease. It has shown to negatively impact HIV care continuum and result in notable non-HIV related morbidity and mortality. With the advancement in antiretroviral therapy and effective direct acting antivirals, fatty liver disease is surfacing as the next big challenge in this population like that observed in the general population. This review article summarizes the gravity of these two common diseases in HIV-infected people and aims to sheds light on an unmet need to develop effective methods to identify, screen and manage fatty liver disease in this unique population.

Human immunodeficiency virus-related peripheral neuropathy: A systematic review and meta-analysis

BACKGROUND AND PURPOSE

Human immunodeficiency virus (HIV)-associated neurological syndromes occur in affected individuals as a consequence of primary HIV infection, opportunistic infections, inflammation and as an adverse effect of some forms of antiretroviral treatment (ART). The aim of this systematic review was to establish the epidemiological characteristics, clinical features, pathogenetic mechanisms and risk factors of HIV-related peripheral neuropathy (PN).

METHODS

A systematic, computer-based search was conducted using the PubMed database. Data regarding the above parameters were extracted. Ninety-four articles were included in this review.

RESULTS

The most commonly described clinical presentation of HIV neuropathy is the distal predominantly sensory polyneuropathy. The primary pathology in HIVPN appears to be axonal rather than demyelinating. Age and treatment with medications belonging in the nucleoside analogue reverse transcriptase class are risk factors for developing HIV-related neuropathy. The pooled prevalence of PN in patients naïve to ARTs was established to be 29% (95% CI: 9%-62%) and increased to 38% (95% confidence interval [CI]: 29%-48%) when looking into patients at various stages of their disease. More than half of patients with HIV-related neuropathy are symptomatic (53%, 95% CI: 41%-63%). Management of HIV-related neuropathy is mainly symptomatic, although there is evidence that discontinuation of some types of ART, such as didanosine, can improve or resolve symptoms.

CONCLUSIONS

Human immunodeficiency virus-related neuropathy is common and represents a significant burden in patients' lives. Our understanding of the disease has grown over the last years, but there are unexplored areas requiring further study.

In utero exposure to protease inhibitor-based antiretroviral regimens delays growth and developmental milestones in mice

Antiretroviral therapy (ART) in pregnancy has dramatically reduced HIV vertical transmission rates. Consequently, there is a growing number of children that are HIV exposed uninfected (CHEUs). Studies suggest that CHEUs exposed in utero to ART may experience developmental delays compared to their peers. We investigated the effects of in utero ART exposure on perinatal neurodevelopment in mice, through assessment of developmental milestones. Developmental milestone tests (parallel to reflex testing in human infants) are reflective of brain maturity and useful in predicting later behavioral outcomes. We hypothesized that ART in pregnancy alters the in utero environment and thereby alters developmental milestone outcomes in pups. Throughout pregnancy, dams were treated with boosted-atazanavir combined with either abacavir/lamivudine (ATV/r/ABC/3TC), or tenofovir/emtricitabine (ATV/r/TDF/FTC), or water as control. Pups were assessed daily for general somatic growth and on a battery of tests for primitive reflexes including surface-righting, negative-geotaxis, cliff-aversion, rooting, ear-twitch, auditory-reflex, forelimb-grasp, air-righting, behaviors in the neonatal open field, and olfactory test. In utero exposure to either ART regimen delayed somatic growth in offspring and evoked significant delays in the development of negative geotaxis, cliff-aversion, and ear-twitch reflexes. Exposure to ATV/r/ABC/3TC was also associated with olfactory deficits in male and forelimb grasp deficits in female pups. To explore whether delays persisted into adulthood we assessed performance in the open field test. We observed no significant differences between treatment arm for males. In females, ATV/r/TDF/FTC exposure was associated with lower total distance travelled and less ambulatory time in the centre, while ATV/r/ABC/3TC exposure was associated with higher resting times compared to controls. In utero PI-based ART exposure delays the appearance of primitive reflexes that involve vestibular and sensory-motor pathways in a mouse model. Our findings suggest that ART could be disrupting the normal progress/maturation of the underlying neurocircuits and encourage further investigation for underlying mechanisms.

Symptoms of Toxicity and Plasma Cytochrome c Levels in Human Immunodeficiency Virus-infected Patients Receiving Anti-retroviral Therapy in Ghana: A Cross-sectional Study

BACKGROUND

Side effects and toxicity have posed a threat to the positive contribution of Antiretroviral Therapy (ART) in the management of human immunodeficiency virus (HIV) infection and Acquired Immune Deficiency Syndrome (AIDS). Symptoms of mitochondrial toxicity including myopathy, pancreatitis, hyperlipidaemia and lactic acidosis are found among HIVinfected patients on ART. To date, there is not a reliable biomarker for monitoring ART-related mitochondrial toxicity. Plasma level of Cytochrome c (Cyt-c) has been proposed as a potential biomarker for ART-related toxicity due to its strong association with apoptosis.

OBJECTIVE

The present study assessed toxicity and level of plasma Cyt-c among HIV-infected patients receiving ART in Ghana.

METHODS

A total of eighty (80) HIV patients were recruited into the study. Demographic data were obtained from personal interview and medical records. Plasma samples were screened for toxicity from sixty (60) participants due to limited resources, and plasma Cyt-c levels were determined using ELISA. Data were analyzed using Stata version 13.

RESULTS

Out of the 60 participants, 11 (18.3%) were found with symptoms of myopathy, 12 (20%) with pancreatitis, 21 (35%) with hyperlipidaemia and 36 (60%) with at least one of the symptoms. The concentration of plasma Cyt-c was higher (0.122 ng/ml) in patients with toxicity than in those without toxicity (0.05 ng/ml), though the difference was not statistically significant (p = 0.148). There was a weak correlation between plasma Cyt-c level and duration of ART (Spearman rho = 0.02, p = 0.89).

CONCLUSION

This study, therefore, demonstrated a high prevalence of ART-related toxicity and high levels of Cyt-c in HIV-infected patients in support of the argument that plasma Cyt-c levels are potential biomarkers for determining ART-related toxicity in HIV patients.

Dominant mutations in mtDNA maintenance gene SSBP1 cause optic atrophy and foveopathy

Mutations in genes encoding components of the mitochondrial DNA (mtDNA) replication machinery cause mtDNA depletion syndromes (MDSs), which associate ocular features with severe neurological syndromes. Here, we identified heterozygous missense mutations in single-strand binding protein 1 (SSBP1) in 5 unrelated families, leading to the R38Q and R107Q amino acid changes in the mitochondrial single-stranded DNA-binding protein, a crucial protein involved in mtDNA replication. All affected individuals presented optic atrophy, associated with foveopathy in half of the cases. To uncover the structural features underlying SSBP1 mutations, we determined a revised SSBP1 crystal structure. Structural analysis suggested that both mutations affect dimer interactions and presumably distort the DNA-binding region. Using patient fibroblasts, we validated that the R38Q variant destabilizes SSBP1 dimer/tetramer formation, affects mtDNA replication, and induces mtDNA depletion. Our study showing that mutations in SSBP1 cause a form of dominant optic atrophy frequently accompanied with foveopathy brings insights into mtDNA maintenance disorders.

Physical Function Impairment and Frailty in Middle-Aged People Living With Human Immunodeficiency Virus in the REPRIEVE Trial Ancillary Study PREPARE

BACKGROUND

People with human immunodeficiency virus (PWH) are at risk for accelerated development of physical function impairment and frailty; both associated with increased risk of falls, hospitalizations, and death. Identifying factors associated with physical function impairment and frailty can help target interventions.

METHODS

The REPRIEVE trial enrolled participants 40-75 years of age, receiving stable antiretroviral therapy with CD4+ T-cell count >100 cells/mm3, and with low to moderate cardiovascular disease risk. We conducted a cross-sectional analysis of those concurrently enrolled in the ancillary study PREPARE at enrollment.

RESULTS

Among the 266 participants, the median age was 51 years; 81% were male, and 45% were black, and 28% had hypertension. Body mass index (BMI; calculated as weight in kilograms divided by height in meters squared) was 25 to <30 in 38% and ≥30 in 30%, 33% had a high waist circumference, 89% were physically inactive, 37% (95% confidence interval, 31%, 43%) had physical function impairment (Short Physical Performance Battery score ≤10), and 6% (4%, 9%) were frail and 42% prefrail. In the adjusted analyses, older age, black race, greater BMI, and physical inactivity were associated with physical function impairment; depression and hypertension were associated with frailty or prefrailty.

CONCLUSIONS

Physical function impairment was common among middle-aged PWH; greater BMI and physical inactivity are important modifiable factors that may prevent further decline in physical function with aging.

CLINICAL TRIALS REGISTRATION

NCT02344290.

Massive release of CD9+ microvesicles in HIV infection, regardless of virologic control

Background

The role of extracellular vesicles (EVs) in human immunodeficiency virus (HIV) pathogenesis is unknown. We examine the cellular origin of plasma microvesicles (MVs), a type of ectocytosis-derived EV, the presence of mitochondria in MVs, and their relationship to circulating cell-free mitochondrial deoxyribonucleic acid (ccf-mtDNA) in HIV-infected patients and controls.

Methods

Five participant groups were defined: 30 antiretroviral therapy (ART)-naive; 30 ART-treated with nondetectable viremia; 30 elite controllers; 30 viremic controllers; and 30 HIV-uninfected controls. Microvesicles were quantified and characterized from plasma samples by flow cytometry. MitoTrackerDeepRed identified MVs containing mitochondria and ccf-mtDNA was quantified by real-time polymerase chain reaction.

Results

Microvesicle numbers were expanded at least 10-fold in all HIV-infected groups compared with controls. More than 79% were platelet-derived MVs. Proportions of MVs containing mitochondria (22.3% vs 41.6%) and MV mitochondrial density (706 vs 1346) were significantly lower among HIV-infected subjects than controls, lowest levels for those on ART. Microvesicle numbers correlated with ccf-mtDNA levels that were higher among HIV-infected patients.

Conclusions

A massive release of platelet-derived MVs occurs during HIV infection. Some MVs contain mitochondria, but their proportion and mitochondrial densities were lower in HIV infection than in controls. Platelet-derived MVs may be biomarkers of platelet activation, possibly reflecting pathogenesis even in absence of HIV replication.

Mitochondrial Toxicogenomics for Antiretroviral Management: HIV Post-exposure Prophylaxis in Uninfected Patients

Background: Mitochondrial genome has been used across multiple fields in research, diagnosis, and toxicogenomics. Several compounds damage mitochondrial DNA (mtDNA), including biological and therapeutic agents like the human immunodeficiency virus (HIV) but also its antiretroviral treatment, leading to adverse clinical manifestations. HIV-infected and treated patients may show impaired mitochondrial and metabolic profile, but specific contribution of viral or treatment toxicity remains elusive. The evaluation of HIV consequences without treatment interference has been performed in naïve (non-treated) patients, but assessment of treatment toxicity without viral interference is usually restricted to in vitro assays.

Objective: The objective of the present study is to determine whether antiretroviral treatment without HIV interference can lead to mtDNA disturbances. We studied clinical, mitochondrial, and metabolic toxicity in non-infected healthy patients who received HIV post-exposure prophylaxis (PEP) to prevent further infection. We assessed two different PEP regimens according to their composition to ascertain if they were the cause of tolerability issues and derived toxicity.

Methods: We analyzed reasons for PEP discontinuation and main secondary effects of treatment withdrawal, mtDNA content from peripheral blood mononuclear cells and metabolic profile, before and after 28 days of PEP, in 23 patients classified depending on PEP composition: one protease inhibitor (PI) plus Zidovudine/Lamivudine (PI plus AZT + 3TC; n = 9) or PI plus Tenofovir/Emtricitabine (PI plus TDF + FTC; n = 14).

Results: Zidovudine-containing-regimens showed an increased risk for drug discontinuation (RR = 9.33; 95% CI = 1.34–65.23) due to adverse effects of medication related to gastrointestinal complications. In the absence of metabolic disturbances, 4-week PEP containing PI plus AZT + 3TC led to higher mitochondrial toxicity (−17.9 ± 25.8 decrease in mtDNA/nDNA levels) than PI plus TDF + FTC (which increased by 43.2 ± 24.3 units mtDNA/nDNA; p < 0.05 between groups). MtDNA changes showed a significant and negative correlation with baseline alanine transaminase levels (p < 0.05), suggesting that a proper hepatic function may protect from antiretroviral toxicity.

Conclusions: In absence of HIV infection, preventive short antiretroviral treatment can cause secondary effects responsible for treatment discontinuation and subclinical mitochondrial damage, especially pyrimidine analogs such as AZT, which still rank as the alternative option and first choice in certain cohorts for PEP. Forthcoming efforts should be focused on launching new strategies with safer clinical and mitotoxic profile.

Dysregulation of sterol regulatory element-binding protein 2 gene in HIV treatment-experienced individuals

Although antiretroviral therapy (ART) has resulted in a marked decrease in AIDS-related morbidity and mortality, the therapeutic benefit is often limited by side effects such as metabolic derangement such as lipodystrophy and hyperlipidemia and cardiovascular diseases. These side effects are pervasive in people living with HIV (PLWH). However, the underlying mechanisms are not completely understood. We investigated the effects of ART on cholesterol biosynthesis genes. This is a retrospective analysis of data and specimens collected during a cross-sectional, case-control study of ART-induced toxicity. Cases were HIV treatment-experienced individuals with HIV viral suppression and no diagnosis of ART-associated toxicity (n = 18), and controls were HIV-uninfected individuals (n = 18). The mRNA expressions of 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR) and ATP binding cassette transporter A1 (ABCA1) were significantly upregulated in cases (HIV+) compared to controls (HIV-), as well as the corresponding protein expression level of HMGCR. We observed dysregulation between sterol regulatory element-binding protein 2 (SREBP-2, sensory control) and HMGCR and low-density lipoprotein receptor (LDLR) pathways. Dysregulation of cholesterol biosynthesis genes may predate clinical manifestation of ART-induced lipid abnormalities.

Senescent Phenotype Induced by p90RSK-NRF2 Signaling Sensitizes Monocytes and Macrophages to Oxidative Stress in HIV-Positive Individuals

BACKGROUND

The incidence of cardiovascular disease is higher in HIV-positive (HIV⁺) patients than it is in the average population, and combination antiretroviral therapy (cART) is a recognized risk factor for cardiovascular disease. However, the molecular mechanisms that link cART and cardiovascular disease are currently unknown. Our study explores the role of the activation of p90RSK, a reactive oxygen species-sensitive kinase, in engendering senescent phenotype in macrophages and accelerating atherogenesis in patients undergoing cART.

METHODS

Peripheral whole blood from cART-treated HIV⁺ individuals and nontreated HIV-negative individuals was treated with H₂O₂ (200 µmol/L) for 4 minutes, and p90RSK activity in CD14⁺ monocytes was measured. Plaque formation in the carotids was also analyzed in these individuals. Macrophage senescence was determined by evaluating their efferocytotic ability, antioxidation-related molecule expression, telomere length, and inflammatory gene expression. The involvement of p90RSK-NRF2 signaling in cART-induced senescence was assessed by p90RSK-specific inhibitor (FMK-MEA) or dominant-negative p90RSK (DN-p90RSK) and NRF2 activator (NRF2A). Further, the severity of atherosclerosis was determined in myeloid cell-specific wild-type and DN-p90RSK transgenic mice.

RESULTS

Monocytes from HIV⁺ patients exhibited higher levels of p90RSK activity and were also more sensitive to reactive oxygen species than monocytes from HIV-negative individuals. A multiple linear regression analysis involving cART, Reynolds cardiovascular risk score, and basal p90RSK activity revealed that cART and basal p90RSK activity were the 2 significant determinants of plaque formation. Many of the antiretroviral drugs individually activated p90RSK, which simultaneously triggered all components of the macrophage senescent phenotype. cART inhibited antioxidant response element reporter activity via ERK5 S496 phosphorylation. NRF2A reversed the H₂O₂-induced overactivation of p90RSK in cART-treated macrophages by countering the induction of senescent phenotype. Last, the data obtained from our gain- or loss-of-function mice conclusively showed the crucial role of p90RSK in inducing senescent phenotype in macrophages and atherogenesis.

CONCLUSIONS

cART increased monocyte/macrophage sensitivity to reactive oxygen species- in HIV⁺ individuals by suppressing NRF2-ARE activity via p90RSK-mediated ERK5 S496 phosphorylation, which coordinately elicited senescent phenotypes and proinflammatory responses. As such, our report underscores the importance of p90RSK regulation in monocytes/macrophages as a viable biomarker and therapeutic target for preventing cardiovascular disease, especially in HIV⁺ patients treated with cART.

A comparison of machine learning techniques for classification of HIV patients with antiretroviral therapy-induced mitochondrial toxicity from those without mitochondrial toxicity

BACKGROUND

Antiretroviral therapy (ART) has significantly reduced HIV-related morbidity and mortality. However, therapeutic benefit of ART is often limited by delayed drug-associated toxicity. Nucleoside reverse transcriptase inhibitors (NRTIs) are the backbone of ART regimens. NRTIs compete with endogenous deoxyribonucleotide triphosphates (dNTPs) in incorporation into elongating DNA chain resulting in their cytotoxic or antiviral effect. Thus, the efficacy of NRTIs could be affected by direct competition with endogenous dNTPs and/or feedback inhibition of their metabolic enzymes. In this paper, we assessed whether the levels of ribonucleotides (RN) and dNTP pool sizes can be used as biomarkers in distinguishing between HIV-infected patients with ART-induced mitochondrial toxicity and HIV-infected patients without toxicity.

METHODS

We used data collected through a case-control study from 50 subjects. Cases were defined as HIV-infected individuals with clinical and/or laboratory evidence of mitochondrial toxicity. Each case was age, gender, and race matched with an HIV-positive without evidence of toxicity. We used a range of machine learning procedures to distinguish between patients with and without toxicity. Using resampling methods like Monte Carlo k-fold cross validation, we compared the accuracy of several machine learning algorithms applied to our data. We used the algorithm with highest classification accuracy rate in evaluating the diagnostic performance of 12 RN and 14 dNTP pool sizes as biomarkers of mitochondrial toxicity.

RESULTS

We used eight classification algorithms to assess the diagnostic performance of RN and dNTP pool sizes distinguishing HIV patients with and without NRTI-associated mitochondrial toxicity. The algorithms resulted in cross-validated classification rates of 0.65-0.76 for dNTP and 0.72-0.83 for RN, following reduction of the dimensionality of the input data. The reduction of input variables improved the classification performance of the algorithms, with the most pronounced improvement for RN. Complex tree-based methods worked the best for both the deoxyribose dataset (Random Forest) and the ribose dataset (Classification Tree and AdaBoost), but it is worth noting that simple methods such as Linear Discriminant Analysis and Logistic Regression were very competitive in terms of classification performance.

CONCLUSIONS

Our finding of changes in RN and dNTP pools in participants with mitochondrial toxicity validates the importance of dNTP pools in mitochondrial function. Hence, levels of RN and dNTP pools can be used as biomarkers of ART-induced mitochondrial toxicity.

Mitochondrial Dysfunction in Aging and Cancer

Aging is a major risk factor for developing cancer, suggesting that these two events may represent two sides of the same coin. It is becoming clear that some mechanisms involved in the aging process are shared with tumorigenesis, through convergent or divergent pathways. Increasing evidence supports a role for mitochondrial dysfunction in promoting aging and in supporting tumorigenesis and cancer progression to a metastatic phenotype. Here, a summary of the current knowledge of three aspects of mitochondrial biology that link mitochondria to aging and cancer is presented. In particular, the focus is on mutations and changes in content of the mitochondrial genome, activation of mitochondria-to-nucleus signaling and the newly discovered mitochondria-telomere communication.

Uridine Prevents Negative Effects of OXPHOS Xenobiotics on Dopaminergic Neuronal Differentiation

Neuronal differentiation appears to be dependent on oxidative phosphorylation capacity. Several drugs inhibit oxidative phosphorylation and might be detrimental for neuronal differentiation. Some pregnant women take these medications during their first weeks of gestation when fetal nervous system is being developed. These treatments might have later negative consequences on the offspring's health. To analyze a potential negative effect of three widely used medications, we studied in vitro dopaminergic neuronal differentiation of cells exposed to pharmacologic concentrations of azidothymidine for acquired immune deficiency syndrome; linezolid for multidrug-resistant tuberculosis; and atovaquone for malaria. We also analyzed the dopaminergic neuronal differentiation in brains of fetuses from pregnant mice exposed to linezolid. The drugs reduced the in vitro oxidative phosphorylation capacity and dopaminergic neuronal differentiation. This differentiation process does not appear to be affected in the prenatally exposed fetus brain. Nevertheless, the global DNA methylation in fetal brain was significantly altered, perhaps linking an early exposure to a negative effect in older life. Uridine was able to prevent the negative effects on in vitro dopaminergic neuronal differentiation and on in vivo global DNA methylation. Uridine could be used as a protective agent against oxidative phosphorylation-inhibiting pharmaceuticals provided during pregnancy when dopaminergic neuronal differentiation is taking place.

Neurologic Complications of Human Immunodeficiency Virus Infection

PURPOSE OF REVIEW

Widespread use of antiretroviral therapy (ART) has led to near-normal life expectancy in people with human immunodeficiency virus (HIV) infection. However, neurologic complications of HIV remain common; can affect any part of the neuraxis; and are due to direct effects of the virus, immunosuppression because of untreated HIV infection, aberrant immune responses in the setting of ART initiation, and ART toxicities.

RECENT FINDINGS

HIV-associated neurocognitive disorder (HAND) remains one of the most common neurologic complications of HIV encountered today, but milder forms predominate in people on ART. No specific treatments for HAND exist, but small trials and epidemiologic evidence suggest paroxetine, intranasal insulin, and maraviroc may have utility in its treatment; further trials of these agents are ongoing. Widespread ART use has decreased the incidence of central nervous system opportunistic infections, but prognosis often remains poor in those who develop opportunistic infections. High-titer positive serum cryptococcal antigen is strongly predictive of cryptococcal meningitis and provides a tool to enhance diagnosis in areas with limited resources. HIV is an independent risk factor for stroke, and accelerated aging associated with HIV infection results in neurologic diseases of older age occurring at much younger ages in individuals infected with HIV. Ongoing HIV replication in the CSF despite peripheral virologic suppression may contribute to the development of HAND and may not improve despite adjusting the ART regimen to increase central nervous system penetrance.

SUMMARY

Neurologists are likely to encounter patients infected with HIV in clinical practice. This article reviews the presentation, diagnosis, and management of the most common neurologic conditions associated with HIV infection and ART.

WS. Characteristics, Prevention, and Management of Cardiovascular Disease in People Living With HIV: A Scientific Statement From the American Heart Association

As early and effective antiretroviral therapy has become more widespread, HIV has transitioned from a progressive, fatal disease to a chronic, manageable disease marked by elevated risk of chronic comorbid diseases, including cardiovascular diseases (CVDs). Rates of myocardial infarction, heart failure, stroke, and other CVD manifestations, including pulmonary hypertension and sudden cardiac death, are significantly higher for people living with HIV than for uninfected control subjects, even in the setting of HIV viral suppression with effective antiretroviral therapy. These elevated risks generally persist after demographic and clinical risk factors are accounted for and may be partly attributed to chronic inflammation and immune dysregulation. Data on long-term CVD outcomes in HIV are limited by the relatively recent epidemiological transition of HIV to a chronic disease. Therefore, our understanding of CVD pathogenesis, prevention, and treatment in HIV relies on large observational studies, randomized controlled trials of HIV therapies that are underpowered to detect CVD end points, and small interventional studies examining surrogate CVD end points. The purpose of this document is to provide a thorough review of the existing evidence on HIV-associated CVD, in particular atherosclerotic CVD (including myocardial infarction and stroke) and heart failure, as well as pragmatic recommendations on how to approach CVD prevention and treatment in HIV in the absence of large-scale randomized controlled trial data. This statement is intended for clinicians caring for people with HIV, individuals living with HIV, and clinical and translational researchers interested in HIV-associated CVD.

Metabolic plasticity of HIV-specific CD8+ T cells is associated with enhanced antiviral potential and natural control of HIV-1 infection

Spontaneous control of human immunodeficiency virus (HIV) is generally associated with an enhanced capacity of CD8⁺ T cells to eliminate infected CD4⁺ T cells, but the molecular characteristics of these highly functional CD8⁺ T cells are largely unknown. In the present study, using single-cell analysis, it was shown that HIV-specific, central memory CD8⁺ T cells from spontaneous HIV controllers (HICs) and antiretrovirally treated non-controllers have opposing transcriptomic profiles. Genes linked to effector functions and survival are upregulated in cells from HICs. In contrast, genes associated with activation, exhaustion and glycolysis are upregulated in cells from non-controllers. It was shown that HIV-specific CD8⁺ T cells from non-controllers are largely glucose dependent, whereas those from HICs have more diverse metabolic resources that enhance both their survival potential and their capacity to develop anti-HIV effector functions. The functional efficiency of the HIV-specific CD8⁺ T cell response in HICs is thus engraved in their memory population and related to their metabolic programme. Metabolic reprogramming in vitro through interleukin-15 treatment abrogated the glucose dependency and enhanced the antiviral potency of HIV-specific CD8⁺ T cells from non-controllers.

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.

Risk of cancer in children exposed to antiretroviral nucleoside analogues in utero: The french experience

All nucleoside analogues for treating HIV infection, due to their capacity to integrate into and alter human DNA, are experimentally genotoxic to some extent. The long-term oncogenic risk after in utero exposure remains to be determined. Cancer incidence in uninfected children exposed to nucleos(t)ide reverse transcriptase inhibitors (NRTIs) was evaluated, by cross-checking against the National Cancer Registry, in the French perinatal study of children born to HIV⁺ mothers. Twenty-one cancers were identified in 15,163 children (median age: 9.9 years [interquartile range (IQR): 5.8-14.2]) exposed to at least one NRTI in utero between 1990 and 2014. Five of these children were exposed to zidovudine monotherapy, and 15 to various combinations, seven of which included didanosine. Overall, the total number of cases was not significantly different from that expected for the general population (SIR = 0.8[0.47-1.24]), but the number of cases after didanosine exposure was twice that expected (SIR = 2.5 [1.01-5.19]). Didanosine accounted for only 10% of prescriptions but was associated with one-third of cancers. In multivariate analysis, didanosine exposure was significantly associated with higher risk (HR = 3.0 [0.9-9.8]). This risk was specifically linked to first-trimester exposure (HR = 5.5 [2.1-14.4]). Three cases of pineoblastoma, a very rare cancer, were observed, whereas 0.03 were expected. Two were associated with didanosine exposure. Despite reassuring data overall, there is strong evidence to suggest that didanosine displays transplacental oncogenicity. These findings cannot be extrapolated to other NRTIs, but they highlight the need for comprehensive evaluations of the transplacental genotoxicity of this antiretroviral class. Environ. Mol. Mutagen., 60:404-409, 2019. © 2017 Wiley Periodicals, Inc.

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.

A Review of Non-Alcoholic Fatty Liver Disease in HIV-Infected Patients: The Next Big Thing?

The burden of liver-related morbidity remains high among HIV-infected patients, despite advances in the treatment of HIV and viral hepatitis. Especially, the impact of non-alcoholic fatty liver disease (NAFLD) is significant with a prevalence of up to 50%. The pathogenesis of NAFLD and the reasons for progression to non-alcoholic steatohepatitis (NASH) are still not fully elucidated, but insulin resistance, mitochondrial dysfunction and dyslipidemia seem to be the main drivers. Both HIV-infection itself and combination antiretroviral therapy (cART) can contribute to the development of NAFLD/NASH in various ways. As ongoing HIV-related immune activation is associated with insulin resistance, early initiation of cART is needed to limit its duration. In addition, the use of early-generation nucleoside reverse transcriptase inhibitors and protease inhibitors is also associated with the development of NAFLD/NASH. Patients at risk should therefore receive antiretroviral drugs with a more favorable metabolic profile. Only weight reduction is considered to be an effective therapy for all patients with NAFLD/NASH, although certain drugs are available for specific subgroups. Since patients with NASH are at risk of developing liver cirrhosis and hepatocellular carcinoma, several non-antifibrotic and antifibrotic drugs are under investigation in clinical trials to broaden the therapeutic options. The epidemiology and etiology of NAFLD/NASH in HIV-positive patients is likely to change in the near future. Current guidelines recommend early initiation of cART that is less likely to induce insulin resistance, mitochondrial dysfunction and dyslipidemia. In contrast, as a result of increasing life expectancy in good health, this population will adopt the more traditional risk factors for NAFLD/NASH. HIV-treating physicians should be aware of the etiology, pathogenesis and treatment of NAFLD/NASH in order to identify and treat the patients at risk.

Hemochromatosis (HFE) Gene Variants Are Associated with Increased Mitochondrial DNA Levels During HIV-1 Infection and Antiretroviral Therapy

Some HIV-associated complications involve mitochondrial dysfunction and may be less common in individuals with iron-loading HFE (hemochromatosis gene) variants. We evaluated HFE 845A and 187G alleles in relation to mitochondrial DNA (mtDNA) levels in peripheral blood mononuclear cells from 85 individuals with HIV infection on uninterrupted antiretroviral therapy (ART) for 15 or more consecutive weeks. Carriers of HFE gene variants (N = 24) had significantly higher mtDNA levels than noncarriers (N = 61), after adjusting for age, race, sex, and type of ART [adjusted β-coefficient 297, p-value < .001 for at least one HFE variant], but mtDNA declined among all individuals on study during 48 weeks on ART. Increased cellular mtDNA content may represent a compensatory response to mitochondrial stress that is influenced by iron-loading HFE variants.

Nephrotoxicity and highly active antiretroviral therapy: Mitigating action of Momordica charantia

Momordica charantia (M. charantia) is known for its antioxidant and antidiabetic properties. The aim of this study is to investigate the renoprotective effects of M. charantia in rats following treatment with highly active antiretroviral therapy (HAART) regimen triplavar. Adult male Sprague-Dawley rats weighing 178.1-220.5 g (n = 36) were divided into six groups (A-F) with each group comprising of six (n = 6) rats. The drugs and extract were administered via oral gavage. The therapeutic dose of triplavar was adjusted using the human therapeutic dose equivalent for the rat model. Animals were euthanized on the tenth week with kidneys removed for examination and blood obtained via cardiac puncture. Levels of oxidative stress enzymes (superoxide dismutase-SOD, catalase-CAT, and reduced glutathione-GSH) were significantly lowered in all groups not receiving M. charantia. The levels of thiobarbituric acid reactive substances (TBARS) were increased resulting in free radical formation via auto-oxidation. Renal parameters showed no albuminuria, normal blood urea nitrogen (BUN), serum creatinine (SCr) and electrolytes in groups treated with M. charantia. HAART treated (Group B) showed severe albuminuria, a significantly (p < 0.05) raised BUN and SCr and gross electrolyte disturbances. Blood glucose levels were significantly raised in groups not receiving the adjuvant M. charantia (p < 0.05). Histopathology in HAART treated animals showed glomerular capillary abnormalities and cellular infiltrations while M. charantia treated animals showed an essentially normal glomerular appearance with capillary loops and normal cytoarchitecture. In conclusion M. charantia extract administration improved blood glucose levels, restored renal histology, reinstate renal function, reduce body weight loss and restores hyperglycemia.

The HIV protease inhibitor, ritonavir, dysregulates human platelet function in vitro

There are 37 million people globally infected with the Human Immunodeficiency Virus (HIV). People living with HIV can achieve nearly normal lifespans due to the use of antiretroviral drugs (ARVs). However, people living with HIV experience chronic inflammation and increased risk for cardiovascular diseases (CVD) relative to uninfected people. While the cause for this risk is unclear, some ARVs have been associated with CVD, and it is speculated that some ARVs potentiate inflammation in infected individuals. Platelets are a critical link between inflammation and the development and progression of CVD, but the effects of ARVs on platelets are largely understudied. In this study, we examined the effects of ARVs on human platelet function in vitro. Our data show that the ARV ritonavir, a protease inhibitor, severely altered human platelet lipid mediator production (prostaglandin E2 and thromboxane) in both resting and activated platelets. Further characterization revealed that ritonavir altered measures of platelet hemostatic and thrombotic function that included significantly decreased platelet spreading, increased platelet aggregation, and trended toward increased clot strength. These data provide proof-of-principle that ARVs can directly dysregulate human platelets, possibly contributing to inflammation-related comorbidities. These data may provide mechanistic insight into the factors contributing to increased risk of CVD in people living with HIV, and may help guide future development of new HIV agents and ARV regimens that mitigate platelet dysregulation by ARVs.

Combination of Tenofovir and Emtricitabine with Efavirenz Does Not Moderate Inhibitory Effect of Efavirenz on Mitochondrial Function and Cholesterol Biosynthesis in Human T Lymphoblastoid Cell Line

Efavirenz (EFV), the most popular nonnucleoside reverse transcriptase inhibitor, has been associated with mitochondrial dysfunction in most in vitro studies. However, in real life the prevalence of EFV-induced mitochondrial toxicity is relatively low. We hypothesized that the agents given in combination with EFV moderate the effect of EFV on mitochondrial function. To test this hypothesis, we cultured a human T lymphoblastoid cell line (CEM cells) with EFV alone and in combination with emtricitabine (FTC) and tenofovir disoproxil fumarate (TDF) to investigate the effects on mitochondrial respiration and function and cholesterol biosynthesis. There was a statistically significant concentration- and time-dependent apoptosis, reduction in mitochondrial membrane potential, and increase in production of reactive oxygen species in cells treated with either EVF alone or in combination with TDF plus FTC. Compared to dimethyl sulfoxide-treated cells, EFV-treated cells had significant reduction in oxygen consumption rate contributed by basal mitochondrial respiration and decreased protein expression of electron transport chain complexes (CI, CII, and CIV). Treatment with EFV resulted in a decrease in mitochondrial DNA content and perturbation of more coding genes (n = 13); among these were 11 genes associated with lipid or cholesterol biosynthesis. Our findings support the growing body of knowledge on the effects of EFV on mitochondrial respiration and function and cholesterol biosynthesis. Interestingly, combining TDF and FTC with EFV did not alter the effects of EFV on mitochondrial respiration and function and cholesterol biosynthesis. The gap between the prevalence of EFV-induced mitochondrial toxicity in in vitro and in vivo studies could be due to individual differences in the pharmacokinetics of EFV.

Non-AIDS Mortality Is Higher Among Successfully Treated People Living with HIV Compared with Matched HIV-Negative Control Persons: A 15-Year Follow-Up Cohort Study in Sweden

There is an ongoing debate whether the life span of successfully treated people living with HIV (PLHIV) is comparable with that of the general population. The aim of this cohort study is to compare all-cause mortality between all PLHIV, successfully treated PLHIV, and HIV-negative control persons from the general population and to explore the impact of viral load (VL) at diagnosis. A total of 4066 PLHIV were matched against 8072 HIV-negative controls according to age, sex, and region of birth. Further, associations between VL at diagnosis, time on treatment, treatment outcome, and mortality were assessed over a 15-year period. Cox regression estimates were computed to compare the overall crude and adjusted hazard ratios (HRs) for mortality. After a 15-year follow-up period, successfully treated PLHIV were found to be three times more likely to die when compared with HIV-negative controls (HR 3.01, 95% CI 2.05–4.44, p < 0.001). The risk of mortality decreased from HR 6.02 after the first year of successful treatment. VL >30,000 c/mL at diagnosis was associated with an increased risk of mortality despite long-term antiretroviral therapy (ART) treatment. Although effective viral suppression has led to significant increases in longevity and quality of life, ART has not fully restored life expectancy to a level comparable with that found in HIV-negative persons. Even when PLHIV are successfully treated, there are several other important areas related to death, such as smoking and social factors, where data are still missing.

The role of mitochondria in aging

The biological basis of human aging remains one of the greatest unanswered scientific questions. Increasing evidence, however, points to a role for alterations in mitochondrial function as a potential central regulator of the aging process. Here, we focus primarily on three aspects of mitochondrial biology that link this ancient organelle to how and why we age. In particular, we discuss the role of mitochondria in regulating the innate immune system, the mechanisms linking mitochondrial quality control to age-dependent pathology, and the possibility that mitochondrial-to-nuclear signaling might regulate the rate of aging.

The role of mitochondria in cellular toxicity as a potential drug target

Mitochondrial malfunction is related to aging and to the onset of many diseases, such as obesity/diabetes, cancer, and cardiovascular and neurodegenerative diseases. The molecular principles of biological and toxicological processes the mitochondria can regulate should be disease-specific, cell type-specific, and drug targetable. Mitochondrial biology and toxicology is evolving and undergoing a revolution through fast-developing biotechnologies garnering increasing attention due to the importance of targeted therapies. Mitochondrial energy production and metabolism are conducted via post-mitochondrial signaling, and are controlled by extra-mitochondrial pathways. Mitochondrial biology and toxicology has a history spanning over 30 years and is one of the main scientific focuses at Cell Biology and Toxicology. It is our aim to pioneer innovations of mitochondrial biology and toxicology to improve the understanding, highlight the latest development, and find mitochondria-based targets for therapies. It is expected to know how drugs can initiate mitochondrial dysfunction, the role of nuclear messages in regulating mitochondrial DNA (MtDNA), and how mitochondria communicate between or with other cells. Further studies are crucial to discover how mitochondria control the process of immune response, autophagy/mitophagy, genome activation, and cell interaction. It is also needed to innovate how the transcription is started and terminated within mitochondria, the cytosolic proteins and other organelles interact with mitochondria, and MtDNA regulates the function of mitochondrial respiratory megacomplexes.