HAART Drugs Induce Oxidative Stress in Human Endothelial Cells and Increase Endothelial Recruitment of Mononuclear Cells: Exacerbation by Inflammatory Cytokines and Amelioration by Antioxidants

Distinct profile of antiviral drugs effects in aortic and pulmonary endothelial cells revealed by high-content microscopy and cell painting assays

Antiretroviral therapy have significantly improved the treatment of viral infections and reduced the associated mortality and morbidity rates. However, highly effective antiretroviral therapy (HAART) may lead to an increased risk of cardiovascular diseases, which could be related to endothelial toxicity. Here, seven antiviral drugs (remdesivir, PF-00835231, ritonavir, lopinavir, efavirenz, zidovudine and abacavir) were characterized against aortic (HAEC) and pulmonary (hLMVEC) endothelial cells, using high-content microscopy. The colourimetric study (MTS test) revealed similar toxicity profiles of all antiviral drugs tested in the concentration range of 1 nM-50 μM in aortic and pulmonary endothelial cells. Conversely, the drugs' effects on morphological parameters were more pronounced in HAECs as compared with hLMVECs. Based on the antiviral drugs' effects on the cytoplasmic and nuclei architecture (analyzed by multiple pre-defined parameters including SER texture and STAR morphology), the studied compounds were classified into five distinct morphological subgroups, each linked to a specific cellular response profile. In relation to morphological subgroup classification, antiviral drugs induced a loss of mitochondrial membrane potential, elevated ROS, changed lipid droplets/lysosomal content, decreased von Willebrand factor expression and micronuclei formation or dysregulated cellular autophagy. In conclusion, based on specific changes in endothelial cytoplasm, nuclei and subcellular morphology, the distinct endothelial response was identified for remdesivir, ritonavir, lopinavir, efavirenz, zidovudine and abacavir treatments. The effects detected in aortic endothelial cells were not detected in pulmonary endothelial cells. Taken together, high-content microscopy has proven to be a robust and informative method for endothelial drug profiling that may prove useful in predicting the organ-specific endothelial toxicity of various drugs.

Exercise to Prevent Accelerated Vascular Aging in People Living With HIV

Given advances in antiretroviral therapy, the mortality rate for HIV infection has dropped considerably over recent decades. However, people living with HIV (PLWH) experience longer life spans coupled with persistent immune activation despite viral suppression and potential toxicity from long-term antiretroviral therapy use. Consequently, PLWH face a cardiovascular disease (CVD) risk more than twice that of the general population, making it the leading cause of death among this group. Here, we briefly review the epidemiology of CVD in PLWH highlighting disparities at the intersections of sex and gender, age, race/ethnicity, and the contributions of social determinants of health and psychosocial stress to increased CVD risk among individuals with marginalized identities. We then overview the pathophysiology of HIV and discuss the primary factors implicated as contributors to CVD risk among PLWH on antiretroviral therapy. Subsequently, we highlight the functional evidence of premature vascular dysfunction as an early pathophysiological determinant of CVD risk among PLWH, discuss several mechanisms underlying premature vascular dysfunction in PLWH, and synthesize current research on the pathophysiological mechanisms underlying accelerated vascular aging in PLWH, focusing on immune activation, chronic inflammation, and oxidative stress. We consider understudied aspects such as HIV-related changes to the gut microbiome and psychosocial stress, which may serve as mechanisms through which exercise can abrogate accelerated vascular aging. Emphasizing the significance of exercise, we review various modalities and their impacts on vascular health, proposing a holistic approach to managing CVD risks in PLWH. The discussion extends to critical future study areas related to vascular aging, CVD, and the efficacy of exercise interventions, with a call for more inclusive research that considers the diversity of the PLWH population.

HIV Infection, Antiretroviral Drugs, and the Vascular Endothelium

Endothelial cell activation, injury, and dysfunction underlies the pathophysiology of vascular diseases and infections associated with vascular dysfunction, including human immunodeficiency virus (HIV) and acquired immunodeficiency syndrome. Despite viral suppression with combination antiretroviral therapy (ART), people living with HIV (PLWH) are prone to many comorbidities, including neurological and neuropsychiatric complications, cardiovascular and metabolic diseases, premature aging, and malignancies. HIV and viral proteins can directly contribute to the development of these comorbidities. However, with the continued high prevalence of these comorbidities despite viral suppression, it is likely that ART or some antiretroviral (ARVs) drugs contribute to the development and persistence of comorbid diseases in PLWH. These comorbid diseases often involve vascular activation, injury, and dysfunction. The purpose of this manuscript is to review the current literature on ARVs and the vascular endothelium in PLWH, animal models, and in vitro studies. I also summarize evidence of an association or lack thereof between ARV drugs or drug classes and the protection or injury/dysfunction of the vascular endothelium and vascular diseases.

Large lessons learned from small vessels: coronary microvascular dysfunction in HIV

PURPOSE OF REVIEW

Large cohort studies have consistently shown the presence of heart failure is approximately doubled among persons with HIV (PWH). Early studies of cardiovascular disease (CVD) in HIV were primarily focused on atherosclerotic burden, and we now have a greater understanding of large vessel disease in HIV. More recent studies have begun to inform us about small vessel disease, or coronary microvascular dysfunction (CMD), in HIV. CMD is recognized to be an important risk factor for adverse events related to heart failure, associated with cardiovascular mortality, and often presents without overt atherosclerotic disease.

RECENT FINDINGS

In this review, we highlight implications for CMD and relevant clinical studies in HIV. Inflammation and endothelial dysfunction, well known risk factors in HIV, may mediate the pathogenesis of CMD. Initial studies suggest that CMD worsens with ART initiation. Newer studies reveal CMD is present among well treated PWH without known CVD. In addition, myocardial flow reserve (MFR), a marker of CMD, is reduced in HIV similar to diabetes. There also appears to be sex differences, such that CMD is worse among women vs. men with HIV.

SUMMARY

Alterations in the coronary microvasculature may be an important mediator of subclinical myocardial dysfunction that deserves further clinical attention among PWH without known CVD.

Involvement of functional senescence in efavirenz-induced toxicity in fruit fly

Background

We aimed in this article to assess the likeliness of efavirenz to induce functional senescence in Drosophila melanogaster (fruit fly).

Methods

Ten different concentrations of EFV were mixed with fly food and fed to 3-day-old flies orally for a 7 day LC50 calculation. Drug concentrations from LC50 were selected for a 28 day survival to determine the duration of treatment for behavioral and biochemical assays. A 5day feeding plan was used to investigate the effects of the drug on organismal, neuromuscular, reproductive, and metabolic senescence. An in silico study was executed to decipher a molecular interaction of Drosophila enzymes glutathione-s-transferase (GST) or acetylcholinesterase (AChE) with EFV.

Results

The calculated LC50 of EFV was 118 mg/10-g fly diet. The test drug induced a significant (P < 0.05) increase in fly mortality, climbing difficulty, and procreative deficits after a 5 day oral exposure. Similarly, there were significant (P < 0.05) biochemical alterations, which suggested in vivo biochemical damage against total thiols (T-SH), SOD (superoxide dismutase), CAT (catalase), GST, AChE, and MDA (malondialdehyde) in the test flies compared to the control groups. In silico study revealed a significantly (P < 0.05) higher binding energy between EFV and the active amino acids of fly AChE and GST when compared to the substrates or standard inhibitors respectively.

Conclusion

EFV exhibited ecotoxic potentials evidenced by age-related deficits in the fly's functional integrity such as sluggish movement, procreative deficiency, increased mortality, and oxidant-antioxidant inequality. Results from in silico study suggested antagonism against GST and AChE activities as a likely mechanism of EFV-induced toxicity in the fruit fly.

Vascular dysfunction and body mass index in African adults with HIV

BACKGROUND

Impaired vascular compliance is common among persons with HIV (PWH) and a risk factor for cardiovascular disease (CVD), though many studies documenting this are from regions with a high prevalence of overweight and obesity. The prevalence and characteristics of impaired vascular compliance among PWH with low body mass index (BMI) is not well described, particularly in sub-Saharan Africa (SSA) where the majority of PWH live, a low BMI is more common, and the burden of CVD is rising.

AIM

To assess non-invasive vascular compliance measurements, including augmentation index (AIX), pulse wave velocity (PWV) and pulse waveforms, in underweight, normal weight, and overweight PWH on long-term antiretroviral therapy (ART) in SSA.

METHODS

A cross-sectional study among PWH on ART at the University Teaching Hospital in Lusaka, Zambia. All participants had been on a regimen of efavirenz, emtricitabine, and tenofovir disoproxil fumarate for five or more years. Carotid-femoral PWV (cfPWV), carotid-radial PWV (crPWV), and the corresponding augmentation indexes (cfAIX and crAIX), were measured in all participants, in addition to aortic pressure waveforms, classified as type A, B, C and D according to reflected wave timings and amplitude. Multiple linear regression assessed relationships between demographic and clinical factors with vascular measurement endpoints.

RESULTS

Ninety one PWH on long-term ART were enrolled; 38 (42%) were underweight (BMI < 18.5 kg/m²), 43 (47%) were normal weight (18.5-24.9 kg/m²) and 10 (11%) were overweight (> 25 kg/m²). Median age was 41, 40 and 40 years, among the three groups, respectively, and the proportion of women increased with BMI level. Overweight participants had a 39% higher cfAIX compared to normal-weight participants, while being underweight was associated with 27% lower cfAIX, after adjusting for age, sex and blood pressure (P = 0.02 and P = 0.01, respectively), but measurements of cfPWV, crPWV and crAIX did not differ.

CONCLUSION

Underweight PWH in SSA had lower cfAIX measurements compared to normal weight individuals, indicating less arterial stiffness. However, similar cfPWV, crPWV and crAIX values among the underweight and overweight PWH suggest a low BMI may not confer substantial protection against impaired vascular compliance as a contributor to CVD risk among individuals on ART.

Spirulina platensis Mitigates the Inhibition of Selected miRNAs that Promote Inflammation in HAART-Treated HepG2 Cells

The introduction of highly active antiretroviral therapy (HAART) in the treatment of HIV/AIDS has recently gained popularity. In addition, the significant role of microRNA expression in HIV pathogenesis cannot be overlooked; hence the need to explore the mechanisms of microRNA expression in the presence of HAART and Spirulina platensis (SP) in HepG2 cells. This study investigates the biochemical mechanisms of microRNA expression in HepG2 cells in the presence of HAART, SP, and the potential synergistic effect of HAART−SP. A 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was used to determine cell viability following SP treatment. The cellular redox status was assessed using the quantification of intracellular reactive oxygen species (ROS), lipid peroxidation, and a lactate dehydrogenase (LDH) assay. The fluorometric JC-1 assay was used to determine mitochondrial polarisation. The quantitative polymerase chain reaction (qPCR) was also employed for micro-RNA and gene expressions. The results show that MiR-146a (p < 0.0001) and miR-155 (p < 0.0001) levels increased in SP-treated cells. However, only miR-146a (p < 0.0001) in HAART−SP indicated an increase, while miR-155 (p < 0.0001) in HAART−SP treatment indicated a significant decreased expression. Further inflammation analysis revealed that Cox-1 mRNA expression was reduced in SP-treated cells (p = 0.4129). However, Cox-1 expression was significantly increased in HAART−SP-treated cells (p < 0.0001). The investigation revealed that HepG2 cells exposed to HAART−SP treatment showed a significant decrease in Cox-2 (p < 0.0001) expression. mRNA expression also decreased in SP-treated cells (p < 0.0001); therefore, SP potentially controls inflammation by regulating microRNA expressions. Moreover, the positive synergistic effect is indicated by normalised intracellular ROS levels (p < 0.0001) in the HAART−SP treatment. We hereby recommend further investigation on the synergistic roles of SP and HAART in the expression of microRNA with more focus on inflammatory and oxidative pathways.

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.

The Role of Selenium in Pathologies: An Updated Review

Selenium is an essential microelement required for a number of biological functions. Selenium—and more specifically the amino acid selenocysteine—is present in at least 25 human selenoproteins involved in a wide variety of essential biological functions, ranging from the regulation of reactive oxygen species (ROS) concentration to the biosynthesis of hormones. These processes also play a central role in preventing and modulating the clinical outcome of several diseases, including cancer, diabetes, Alzheimer’s disease, mental disorders, cardiovascular disorders, fertility impairments, inflammation, and infections (including SARS-CoV-2). Over the past years, a number of studies focusing on the relationship between selenium and such pathologies have been reported. Generally, an adequate selenium nutritional state—and in some cases selenium supplementation—have been related to improved prognostic outcome and reduced risk of developing several diseases. On the other hand, supra-nutritional levels might have adverse effects. The results of recent studies focusing on these topics are summarized and discussed in this review, with particular emphasis on advances achieved in the last decade.

Circulating Hydrogen Sulfide (H2S) and Nitric Oxide (NO) Levels Are Significantly Reduced in HIV Patients Concomitant with Increased Oxidative Stress Biomarkers

Human immunodeficiency virus (HIV) attacks the immune system and weakens the ability to fight infections/disease. Furthermore, HIV infection confers approximately two-fold higher risk of cardiac events compared with the general population. The pathological mechanisms responsible for the increased incidence of cardiovascular disease in HIV patients are largely unknown. We hypothesized that increased oxidative stress and attenuated circulating levels of the cardioprotective gaseous signaling molecules, nitric oxide (NO), and hydrogen sulfide (H₂S) were involved in the cardiovascular pathobiology observed in HIV patients. Plasma samples from both HIV patients and age-matched normal subjects were used for all assays. Oxidative stress was determined by analyzing the levels of advanced oxidation protein products (AOPP) and H₂O₂. Antioxidant levels were determined by measuring the levels of trolox equivalent capacity. ADMA, hs-CRP, and IL-6 were determined by using ELISA. The levels of H₂S (free H₂S and sulfane sulfur) and NO₂ (nitrite) were determined in the plasma samples by using gas chromatography and HPLC, respectively. In the present study we observed a marked induction in the levels of oxidative stress and decreased antioxidant status in the plasma of HIV patients as compared with the controls. Circulating levels of the cardiovascular disease biomarkers: ADMA, hs-CRP (high-sensitivity C-reactive protein), and IL-6 were significantly increased in the circulatory system of HIV patients. The levels of both nitrite and H₂S/sulfane sulfur were significantly reduced in the plasma of HIV patients as compared with normal subjects. Our data demonstrate significant increases in circulating biomarkers of oxidative stress and cardiovascular (CV) in conjunction with decreased bioavailability of H₂S and NO in HIV patients. Diminished levels of these two cardioprotective gaseous signaling molecules may be involved in the pathogenesis of CV disease in the setting of HIV.

Antioxidant nanozyme counteracts HIV-1 by modulating intracellular redox potential

Reactive oxygen species (ROS) regulates the replication of human immunodeficiency virus (HIV‐1) during infection. However, the application of this knowledge to develop therapeutic strategies remained unsuccessful due to the harmful consequences of manipulating cellular antioxidant systems. Here, we show that vanadium pentoxide (V₂O₅) nanosheets functionally mimic natural glutathione peroxidase activity to mitigate ROS associated with HIV‐1 infection without adversely affecting cellular physiology. Using genetic reporters of glutathione redox potential and hydrogen peroxide, we showed that V₂O₅ nanosheets catalyze ROS neutralization in HIV‐1‐infected cells and uniformly block viral reactivation and replication. Mechanistically, V₂O₅ nanosheets suppressed HIV‐1 by affecting the expression of pathways coordinating redox balance, virus transactivation (e.g., NF‐κB), inflammation, and apoptosis. Importantly, a combination of V₂O₅ nanosheets with a pharmacological inhibitor of NF‐κB (BAY11‐7082) abrogated reactivation of HIV‐1. Lastly, V₂O₅ nanosheets inhibit viral reactivation upon prostratin stimulation of latently infected CD4⁺ T cells from HIV‐infected patients receiving suppressive antiretroviral therapy. Our data successfully revealed the usefulness of V₂O₅ nanosheets against HIV and suggested nanozymes as future platforms to develop interventions against infectious diseases.

Cerebral Vascular Toxicity of Antiretroviral Therapy

HIV infection is associated with comorbidities that are likely to be driven not only by HIV itself, but also by the toxicity of long-term use of antiretroviral therapy (ART). Indeed, increasing evidence demonstrates that the antiretroviral drugs used for HIV treatment have toxic effects resulting in various cellular and tissue pathologies. The blood-brain barrier (BBB) is a modulated anatomophysiological interface which separates and controls substance exchange between the blood and the brain parenchyma; therefore, it is particularly exposed to ART-induced toxicity. Balancing the health risks and gains of ART has to be considered in order to maximize the positive effects of therapy. The current review discusses the cerebrovascular toxicity of ART, with the focus on mitochondrial dysfunction. Graphical Abstract Graphical representation of the interactions between HIV, antiretroviral therapy (ART), and the blood-brain barrier (BBB).

The Potential Contribution of Caveolin 1 to HIV Latent Infection

Combinatorial antiretroviral therapy (cART) suppresses HIV replication to undetectable levels and has been effective in prolonging the lives of HIV infected individuals. However, cART is not capable of eradicating HIV from infected individuals mainly due to HIV’s persistence in small reservoirs of latently infected resting cells. Latent infection occurs when the HIV-1 provirus becomes transcriptionally inactive and several mechanisms that contribute to the silencing of HIV transcription have been described. Despite these advances, latent infection remains a major hurdle to cure HIV infected individuals. Therefore, there is a need for more understanding of novel mechanisms that are associated with latent infection to purge HIV from infected individuals thoroughly. Caveolin 1(Cav-1) is a multifaceted functional protein expressed in many cell types. The expression of Cav-1 in lymphocytes has been controversial. Recent evidence, however, convincingly established the expression of Cav-1 in lymphocytes. In lieu of this finding, the current review examines the potential role of Cav-1 in HIV latent infection and provides a perspective that helps uncover new insights to understand HIV latent infection.

The far-reaching HAND of cART: cART effects on astrocytes

Following the introduction of combination antiretroviral therapy (cART), the morbidity and mortality from human immunodeficiency virus (HIV) infection has been drastically curtailed and HIV has now become a chronic manageable disease. Persons living with HIV (PLWH) are living longer and experiencing significant co-morbidities and conditions of aging. NeuroHIV, clinically defined as HIV-Associated Neurocognitive Disorders (HAND) and pathologically manifested by persistent inflammation in the CNS despite cART, is a significant co-morbid condition for PLWH. In the pre-cART era, HIV mediated much of the pathogenesis in the Central Nervous System (CNS); in the cART era, with low to undetectable viremia, other mechanisms may be contributing to persistent neuroinflammation. Emerging data point to the adverse effects at the cellular level of cART, independent of HIV. Astrocytes are the most abundant cells in the CNS, playing vital roles in maintaining CNS homeostasis (e.g. metabolic support to neurons, clearance of neurotransmitters, ion balance, modulation of synaptic functions and maintaining the structural integrity of the blood brain barrier (BBB). Therefore, any disruption of their function will have wide repercussions in the CNS. In this review, we will address current knowledge and gaps on the impact of antiretrovirals (ARVs) on astrocytes and physiologic consequences in the CNS. Understanding the status of this field, will provide a practical framework to elucidate the potential role of cART-mediated dysregulation of astrocytes in neuroHIV pathogenesis and inform therapeutic strategies that are "neuro-friendly". Graphical abstract CNS-penetrating cART have the potential to cause resting astrocytes to become activated into an A1 or neurotoxic phenotype. These cells can in turn secrete inflammatory cytokines that affect surrounding microglia macrophages, as well as neurotoxic factors that impact nearby neurons. In addition, impairment in the physiologic functions of astrocytes will result in altered BBB permeability and disrupted metabolic homeostasis. CNS=Central Nervous System; cART=combined antiretroviral therapy; BBB=blood brain barrier.

Genomic Instability Decreases in HIV Patient by Complementary Therapy with Rosmarinus officinalis Extracts

Genomic instability is associated with increased oxidative stress in patients with human immunodeficiency virus (HIV). The aim of this study was to determine the effect of intake of methanolic and aqueous extracts of Rosmarinus officinalis on genomic instability in HIV patients. We studied 67 HIV patients under pharmacological treatment with ATRIPLA who were divided into three groups: group 1, patients under ATRIPLA antiretroviral therapy; group 2, patients with ATRIPLA and rosemary aqueous extract (4 g/L per day); and group 3, patients with ATRIPLA and rosemary methanolic extract (400 mg/day). The genomic instability was evaluated through the buccal micronucleus cytome assay. Oral epithelial cells were taken at the beginning and 1 and 4 months later. The groups that received the pharmacological therapy with ATRIPLA and the complementary therapy with R. officinalis extracts showed a decrease in the number of cells with micronuclei and nuclear abnormalities compared with the group that only received ATRIPLA. The complementary therapy with R. officinalis decreased the genomic instability in HIV patients.

Repositioning of HIV Aspartyl Peptidase Inhibitors for Combating the Neglected Human Pathogen Trypanosoma cruzi

Chagas disease, caused by the flagellate parasite Trypanosoma cruzi, is a wellknown neglected tropical disease. This parasitic illness affects 6-7 million people and can lead to severe myocarditis and/or complications of the digestive tract. The changes in its epidemiology facilitate co-infection with the Human Immunodeficiency Virus (HIV), making even more difficult the diagnosis and prognosis. The parasitic infection is reactivated in T. cruzi/HIV co-infection, with the appearance of unusual manifestations in the chronic phase and the exacerbation of classical clinical signs. The therapeutic arsenal to treat Chagas disease, in all its clinical forms, is restricted basically to two drugs, benznidazole and nifurtimox. Both drugs are extremely toxic and the therapeutic efficacy is still unclear, making the clinical treatment a huge issue to be solved. Therefore, it seems obvious the necessity of new tangible approaches to combat this illness. In this sense, the repositioning of approved drugs appears as an interesting and viable strategy. The discovery of Human Immunodeficiency Virus Aspartyl Peptidase Inhibitors (HIV-PIs) represented a milestone in the treatment of Acquired Immune Deficiency Syndrome (AIDS) and, concomitantly, a marked reduction in both the incidence and prevalence of important bacterial, fungal and parasitic co-infections was clearly observed. Taking all these findings into consideration, the present review summarizes the promising and beneficial data concerning the effects of HIV-PIs on all the evolutionary forms of T. cruzi and in important steps of the parasite's life cycle, which highlight their possible application as alternative drugs to treat Chagas disease.

Oxidative stress response in the pathogenesis of dengue virus virulence, disease prognosis and therapeutics: an update

Dengue virus (DENV) is a mosquito-borne arbovirus that causes febrile illness and can lead to a potentially lethal disease. The mechanism of disease pathogenesis is not completely understood, and there are currently no vaccines or therapeutic drugs available to protect against all four serotypes of DENV. Although many reasons have been suggested for the development of the disease, dengue studies have shown that, during DENV infection, there is an imbalance between oxidants and antioxidants that disrupts homeostasis. An increase in reactive oxygen species (ROS) levels triggers the sudden release of cytokines, which can lead to plasma leakage and other severe symptoms. In the present review, we give an overview of the oxidative stress response and its effect on the progression of dengue disease. We also discuss the role of oxidative-stress-associated molecules in disease prognostic and therapeutics.

White matter loss and oligodendrocyte dysfunction in HIV: A consequence of the infection, the antiretroviral therapy or both?

While the severe cognitive effects of HIV-associated dementia have been reduced by combined antiretroviral therapy (cART), nearly half of HIV-positive (HIV+) patients still suffer from some form of HIV-Associated Neurocognitive Disorders (HAND). While frank neuronal loss has been dramatically reduced in HAND patients, white matter loss, including dramatic thinning of the corpus callosum, and loss of volume and structural integrity of myelin persists despite viral control by cART. It remains unclear whether changes in white matter underlie the clinical manifestation seen in patients or whether they are the result of persistent viral reservoirs, remnant damage from the acute infection, the antiretroviral compounds used to treat HIV, secondary effects due to peripheral toxicities or other associated comorbid conditions. Both HIV infection itself and its treatment with antiretroviral drugs can induce metabolic syndrome, lipodystrophy, atherosclerosis and peripheral neuropathies by increased oxidative stress, induction of the unfolded protein response and dysregulation of lipid metabolism. These virally and/or cART-induced processes can also cause myelin loss in the CNS. This review aims to highlight existing data on the contribution of white matter damage to HAND and explore the mechanisms by which HIV infection and its treatment contribute to persistence of white matter changes in people living with HIV currently on cART.

Association of antiretroviral therapy with brain aging changes among HIV-infected adults

OBJECTIVE

Antiretroviral therapy (ART) is currently recommended for all persons living with HIV (PLWH), regardless of their CD4 T-cell count, and should be continued throughout life. Nonetheless, vigilance of the safety of ART, including its neurotoxicity, must continue. We hypothesized that use of certain ART drugs might be associated with aging-related cerebral degenerative changes among PLWH.

DESIGN

Clinicopathological study of PLWH who were using ART drugs at the last clinical assessment.

METHODS

Using multivariable logistic regression, we tested associations between use of each specific ART drug (with reference to use of other ART drugs) and cerebral degenerative changes including neuronal phospho-tau lesions, β-amyloid plaque deposition, microgliosis, and astrogliosis in the frontal cortex and putamen (immunohistochemistry), as well as cerebral small vessel disease (CSVD) in the forebrain white matter (standard histopathology), with relevant covariates being taken into account. The Bonferroni adjustment was applied.

RESULTS

Darunavir use was associated with higher likelihood of neuronal phospho-tau lesions in the putamen [odds ratio (OR) 15.33, n = 93, P = 0.005]. Ritonavir use was associated with marked microgliosis in the putamen (OR 4.96, n = 101, P = 0.023). On the other hand, use of tenofovir disoproxil fumarate was associated with lower likelihood of β-amyloid plaque deposition in the frontal cortex (OR 0.13, n = 102, P = 0.012). There was a trend toward an association between emtricitabine use and CSVD (OR 13.64, n = 75, P = 0.099).

CONCLUSION

Our findings suggest that PLWH treated with darunavir and ritonavir may be at increased risk of aging-related cerebral degenerative changes.

Effect of anti-retroviral therapy on oxidative stress in hospitalized HIV-infected adults with and without TB

Background

HIV infection and opportunistic infections cause oxidative stress (OS), which is associated with tissue damage. Anti-retroviral therapy (ART) is used to treat HIV and decrease the risk of opportunistic infections, but it is unclear whether ART reduces OS. Association of ART with OS was investigated.

Methods

We stratified a convenience sample of frozen serum or plasma from HIV-infected, ART-naïve (n=21); HIV-infected, ART-treated (n=14); HIV and PTB co-infected, ART-naïve (n=21); HIV and PTB co-infected, ART-treated (n=25) patients. Controls (n=21) were HIV-negative adults without TB symptoms. Concentration of OS markers namely: transaminases (ALT and AST), gamma glutamyl transpeptidase (GGT), albumin, total protein, malondialdehyde (MDA), vitamin C, and total anti-oxidant status (TAS) were determined.

Results

AST (p<0.001), GGT (p<0.001), total protein (p=0.001) and MDA (p<0.001) were higher in HIV patients compared to controls. Vitamin C (P<0.0001) and albumin (p<0.01) were lower in HIV-patients relative to controls. ART was only associated with higher albumin (p=0.001), higher GGT (p=0.02) and lower vitamin C (p=0.009). HIV and PTB co-infection was only significantly associated with higher GGT (p=0.01) and AST (p=0.03).

Conclusion

We identified severe OS among HIV-patients. ART was associated with both increased and reduced markers of OS hence suggesting that ART may not attenuate OS.

Beyond the polymerase-γ theory: Production of ROS as a mode of NRTI-induced mitochondrial toxicity

Use of some HIV-1 nucleoside reverse transcriptase inhibitors (NRTI) is associated with severe adverse events. However, the exact mechanisms behind their toxicity has not been fully understood. Mitochondrial dysfunction after chronic exposure to specific NRTIs has predominantly been assigned to mitochondrial polymerase-γ inhibition by NRTIs. However, an increasing amount of data suggests that this is not the sole mechanism. Many NRTI induced adverse events have been linked to the incurrence of oxidative stress, although the causality of events leading to reactive oxygen species (ROS) production and their role in toxicity is unclear. In this study we show that short-term effects of first generation NRTIs, which are rarely discussed in the literature, include inhibition of oxygen consumption, decreased ATP levels and increased ROS production. Collectively these events affect fitness and longevity of C. elegans through mitohormetic signalling events. Furthermore, we demonstrate that these effects can be normalized by addition of the anti-oxidant N-acetylcysteine (NAC), which suggests that ROS likely influence the onset and severity of adverse events upon drug exposure.

HIV infection, antiretroviral therapy, and measures of endothelial function, inflammation, metabolism, and oxidative stress

Background

HIV-infected patients have an increased risk of cardiovascular disease (CVD). Impaired endothelial function is an early risk factor for CVD in the general population. It is presumed that HIV infection is associated with impaired endothelial function, but results have been inconsistent.

Objectives

Our objectives were to determine the relationships between HIV infection, virologic suppression with antiretroviral therapy (ART), in vivo measures of conduit artery and microvascular endothelial function, and circulating biomarkers of pathways associated with CVD.

Methods

We performed a cross-sectional analysis of three prospectively enrolled groups from a single center: 28 were HIV-infected and virologically-suppressed on a regimen of FTC/TDF/EFV (HIV+ART+), 44 were HIV-infected but not on ART (HIV+ART-), and 39 were HIV-uninfected healthy volunteers (HIV-) matched to the HIV+ART- group for age, sex, smoking status, and height. None had diabetes, uncontrolled hypertension, known CVD, or other pro-inflammatory condition. Flow mediated dilation (FMD), nitroglycerin-mediated dilation (NTGMD), reactive hyperemia velocity time integral (RHVTI), and FMD/RHVTI of the brachial artery were measured, as well as circulating biomarkers of systemic inflammation, metabolism, oxidative stress, and endothelial activation.

Results

No significant differences were found amongst the three groups in FMD (P = 0.46), NTGMD (P = 0.42), RHVTI (P = 0.17), and FMD/RHVTI (P = 0.22) in unadjusted comparisons. Adjusted ANOVA models which included brachial artery diameter, demographics, and conventional CVD risk factors did not appreciably change these findings. In pairwise comparisons, the HIV+ART- group had significantly higher soluble tumor necrosis factor receptor II, soluble CD163, β-2 microglobulin, interferon-γ- induced protein-10, tissue inhibitor of metalloproteinase-1, and vascular cell adhesion molecule-1 compared to the other two groups (all p<0.05). Correlates of endothelial function differed between study groups.

Conclusion

Although untreated HIV infection was associated with elevated levels of several biomarkers of inflammation and endothelial activation, we were unable to demonstrate differences in measures of conduit artery and microvascular endothelial function in this study population.

Oxidative Stress during HIV Infection: Mechanisms and Consequences

It is generally acknowledged that reactive oxygen species (ROS) play crucial roles in a variety of natural processes in cells. If increased to levels which cannot be neutralized by the defense mechanisms, they damage biological molecules, alter their functions, and also act as signaling molecules thus generating a spectrum of pathologies. In this review, we summarize current data on oxidative stress markers associated with human immunodeficiency virus type-1 (HIV-1) infection, analyze mechanisms by which this virus triggers massive ROS production, and describe the status of various defense mechanisms of the infected host cell. In addition, we have scrutinized scarce data on the effect of ROS on HIV-1 replication. Finally, we present current state of knowledge on the redox alterations as crucial factors of HIV-1 pathogenicity, such as neurotoxicity and dementia, exhaustion of CD4+/CD8+ T-cells, predisposition to lung infections, and certain side effects of the antiretroviral therapy, and compare them to the pathologies associated with the nitrosative stress.

Efavirenz Causes Oxidative Stress, Endoplasmic Reticulum Stress, and Autophagy in Endothelial Cells

The non-nucleoside reverse transcriptase inhibitor efavirenz is a widely prescribed antiretroviral drug used in combined antiretroviral therapy. Despite being an essential and life-saving medication, the required lifelong use of HIV drugs has been associated with a variety of adverse effects, including disturbances in lipid metabolism and increased cardiovascular risk. Efavirenz belongs to those HIV drugs for which cardiovascular and endothelial dysfunctions have been reported. It is here shown that elevated concentrations of efavirenz can inhibit endothelial meshwork formation on extracellular matrix gels by normal and immortalized human umbilical vein cells. This inhibition was associated with an increase in oxidative stress markers, endoplasmic reticulum (ER) stress markers, and autophagy. Induction of ER stress occurred at pharmacologically relevant concentrations of efavirenz and resulted in reduced proliferation and cell viability of endothelial cells, which worsened in the presence of elevated efavirenz concentrations. In combination with the HIV protease inhibitor nelfinavir, both oxidative stress and ER stress became elevated in endothelial cells. These data indicate that pharmacologically relevant concentrations of efavirenz can impair cell viability of endothelial cells and that these effects may be aggravated by either elevated concentrations of efavirenz or by a combined use of efavirenz with other oxidative stress-inducing medications.

Neurotoxicity in the Post-HAART Era: Caution for the Antiretroviral Therapeutics

Despite the advent of highly active antiretroviral therapy (HAART), HIV-associated neurological disorders (HAND) remain a major challenge in human immunodeficiency virus (HIV) treatment. The early implementation of HAART in the infected individuals helps suppress the viral replication in the plasma and other compartments. Several studies also report the beneficial effect of drugs that successfully penetrate central nervous system (CNS). However, recent data in both clinical setup and in in vitro studies indicate CNS toxicity of the antiretrovirals (ARVs). Although the evidence is limited, correlation between prolonged use of ARVs and neurotoxicity strongly suggests that it is essential to study the underlying mechanisms responsible for such toxicity. Furthermore, closer attention toward clinical outcomes is required to screen various ARV regimens for their association with HAND and other comorbidities. A growing body of literature also indicates a possible role of accelerated aging in the antiretroviral therapy-associated neurotoxicity. Lastly, owing to high pill burden, multiple drugs in the HIV treatment also invite a possible role of drug-drug interaction via various cytochrome P450 enzymes. The particular emphasis of this review is to highlight the need to identify alternative approaches in reducing the CNS toxicity of the ARV drugs in HIV-infected individuals.

Hyperglycemia exacerbates antiretroviral drug combination induced blood-brain barrier endothelial toxicity

In this study, we sought to investigate how concomitant hyperglycemia influences the impact of combination antiretroviral therapy on blood-brain barrier (BBB) endothelial function. Immortalized human brain microvascular endothelial cell line (hCMEC/D3) was exposed to azidothymidine (AZT; a nucleoside reverse transcriptase inhibitor) and/or indinavir (IND; protease inhibitor) in normal glycemic (5.5mM) or hyperglycemic (HG; 25mM) media containing D-glucose for 24-72h. Cellular reactive oxygen species (ROS) and mitochondria-specific superoxide levels were assayed in addition to membrane potential to determine the extent of mitochondrial dysfunction. Nrf2 expression was analyzed by immunofluorescence. Our results indicated a significant increase in BBB endothelial toxicity (decreased ATP) by HG and AZT+IND with progression of time (24-72h). Concurrent HG and antiviral drug combination synergistically elevated BBB endothelial ROS induced by either condition alone. Further, HG and AZT+IND mutually interact to elicit a pronounced increase in mitochondrial superoxide levels post 24h (vs. either condition alone or controls). In addition, HG and AZT+IND complemented each other to induce potential loss of mitochondrial membrane potential. While HG or AZT+IND alone for 24h increased Nrf2 nuclear distribution, co-exposure conditions induced a potential loss of Nrf2 expression/nuclear translocation in BBB endothelium. In summary, our data strongly suggest that antiretroviral drug combination potentially interacts with concomitant HG and triggers exacerbated mitochondrial dysfunction and BBB endothelial toxicity, possibly through dysregulation of Nrf2 signaling. Thus, this study warrants the critical need for safety evaluation and monitoring of neurovascular complications of HAART regimens in HIV-infected diabetic patient cohort.

Heme oxygenase-1-derived bilirubin counteracts HIV protease inhibitor-mediated endothelial cell dysfunction

The use of HIV protease inhibitors (PIs) has extended the duration and quality of life for HIV-positive individuals. However there is increasing concern that this antiviral therapy may promote premature cardiovascular disease by impairing endothelial cell (EC) function. In the present study, we investigated the effect of HIV PIs on EC function and determined if the enzyme heme oxygenase (HO-1) influences the biological action of these drugs. We found that three distinct PIs, including ritonavir, atazanavir, and lopinavir, stimulated the expression of HO-1 protein and mRNA. The induction of HO-1 was associated with an increase in NF-E2-related factor-2 (Nrf2) activity and reactive oxygen species (ROS). PIs also stimulated HO-1 promoter activity and this was prevented by mutating the antioxidant responsive element or by overexpressing dominant-negative Nrf2. In addition, the PI-mediated induction of HO-1 was abolished by N-acetyl-l-cysteine and rotenone. Furthermore, PIs blocked EC proliferation and migration and stimulated the expression of intercellular adhesion molecule-1 and the adhesion of monocytes on ECs. Inhibition of HO-1 activity or expression potentiated the anti-proliferative and inflammatory actions of PIs which was reversed by bilirubin but not carbon monoxide. Alternatively, adenovirus-mediated overexpression of HO-1 attenuated the growth-inhibitory and inflammatory effect of PIs. In contrast, blocking HO-1 activity failed to modify the anti-migratory effect of the PIs. Thus, induction of HO-1 via the ROS-Nrf2 pathway in human ECs counteracts the anti-proliferative and inflammatory actions of PIs by generating bilirubin. Therapeutic approaches targeting HO-1 may provide a novel approach in preventing EC dysfunction and vascular disease in HIV-infected patients undergoing antiretroviral therapy.

An Ex Vivo Tissue Culture Model for Anti-angiogenic Drug Testing

Angiogenesis, defined as the growth of new blood vessels from existing ones, plays a key role in development, growth, and tissue repair. Its necessary role in tumor growth and metastasis has led to the creation of a new category of anti-angiogenic cancer therapies. Preclinical development and evaluation of potential drug candidates require models that mimic real microvascular networks. Here, we describe the rat mesentery culture model as a simple ex vivo assay that offers time-lapse imaging of intact microvascular network remodeling and demonstrate its application for anti-angiogenic drug testing.

Prolonged exposure to lopinavir impairs endothelium-dependent hyperpolarization-mediated relaxation in rat mesenteric arteries

Protease inhibitors (PIs) and non-nucleoside reverse transcriptase inhibitors are effective antiretroviral drugs, but their use is associated with a high incidence of cardiovascular disease. As vascular dysfunction precedes cardiovascular events, this study aimed to examine the vascular effects of clinically used PIs (indinavir, lopinavir, nelfinavir, ritonavir, saquinavir, and tipranavir) and non-nucleoside reverse transcriptase inhibitors (efavirenz and nevirapine). Rat mesenteric arteries were suspended in conventional organ chambers for isometric tension recording. Efavirenz, indinavir, nelfinavir, ritonavir, and tipranavir, but not saquinavir and nevirapine, caused endothelium-independent relaxations. Lopinavir induced both endothelium-dependent and -independent relaxations; the former was inhibited by nitric oxide (NO) synthase inhibitor. Incubation with lopinavir for 24 hours reduced relaxations attributable to endothelium-derived hyperpolarization. Relaxations to the adenosine triphosphate-sensitive potassium (K(ATP)) channel opener, levcromakalim, but not those to the NO donor, sodium nitroprusside, were also inhibited. Western blotting indicated that the protein expressions of intermediate (IK(Ca)) and small (SK(Ca)) conductance calcium-activated potassium channels and K(ATP) channel were reduced in mesenteric arteries incubated with lopinavir for 24 hours. In conclusion, lopinavir differs from other PIs in that it acutely induces endothelium-derived NO-mediated relaxation. However, prolonged exposure to lopinavir impairs relaxations, likely by reducing the expressions of IK(Ca), SK(Ca), and K(ATP) channels.

Impact of darunavir, atazanavir and lopinavir boosted with ritonavir on cultured human endothelial cells: beneficial effect of pravastatin

BACKGROUND

HIV-infected patients administered long-term ritonavir-boosted protease inhibitors (PIs) are at a greater risk for developing cardiovascular diseases. Endothelial dysfunction is an initiating event in HIV-associated atherosclerosis. Cultured endothelial cells can be used as a model to compare the endothelial toxicity of different PIs.

METHODS

We compared the effect of darunavir (DRV), darunavir/ritonavir (DRV/r), lopinavir/ritonavir (LPV/r) and atazanavir/ritonavir (ATV/r), used at clinically relevant concentrations, on human coronary artery endothelial cell vascular function, oxidative stress, inflammation and senescence, and studied the effect of pravastatin on PI-induced alterations.

RESULTS

Vascular endothelial cell function, evaluated by the expression of endothelial nitric oxide synthase and the production of nitric oxide and endothelin-1, was unaffected by DRV or DRV/r, but altered by LPV/r or ATV/r. DRV or DRV/r did not alter, or mildly induced oxidative stress and inflammation (phosphorylation of p65/RelA-NFκB, secretion of IL-6 and IL-8), while ATV/r and LPV/r induced a marked increase. Secretion of sICAM or sVCAM, indicative of altered cell integrity, was not or weakly altered by DRV or DRV/r, but increased by 2-3-fold by LPV/r or ATV/r. Similar results were observed regarding senescence markers: SA-β-galactosidase activation and overexpression of phospho-p53, p16(ink4), p21(WAF-1) and prelamin A. Pravastatin could, in part, reverse PI-induced adverse effects.

CONCLUSIONS

Ritonavir-boosted PIs differentially induced vascular endothelial cell dysfunction, reactive oxygen species production, inflammation and senescence with no effect or a mild effect of DRV/r, an intermediate effect of ATV/r, and a stronger effect of LPV/r. Statins could, in part, protect the cells from PI-induced endothelial dysfunction.

Efavirenz induces interactions between leucocytes and endothelium through the activation of Mac-1 and gp150,95

OBJECTIVES

The potential cardiovascular (CV) toxicity associated with combined antiretroviral therapy (cART) has been attributed mainly to the nucleoside reverse transcriptase inhibitors abacavir and didanosine. However, the other two components of cART--non-nucleoside reverse transcriptase inhibitors (NNRTIs) and protease inhibitors (PIs)--may also be implicated, either directly or by influencing the action of the other drugs. This study evaluates the acute direct effects of the NNRTIs efavirenz and nevirapine and one of the most widely employed PIs, lopinavir, on leucocyte-endothelium interactions, a hallmark of CV disease.

METHODS

Drugs were analysed in vitro in human cells (interactions of peripheral blood polymorphonuclear or mononuclear cells with human umbilical vein endothelial cells) using a flow chamber system, and in vivo in rat mesenteric vessels by means of intravital microscopy. The expression of adhesion molecules in leucocytes and endothelial cells was studied by flow cytometry, and the role of these molecules in white cell recruitment was evaluated by pre-treating human cells or rats with blocking antibodies.

RESULTS

Efavirenz and nevirapine, but not lopinavir, increased the rolling flux and adhesion of leucocytes in vitro and in vivo while inducing emigration in rat venules. Efavirenz, but not nevirapine, augmented the levels of CD11b, CD11c and CD18 in neutrophils and monocytes. The actions of efavirenz, but not of nevirapine, were reversed by antibodies against Mac-1 (CD11b/CD18), gp150,95 (CD11c/CD18) or ICAM-1 (CD54).

CONCLUSIONS

NNRTIs, but not PIs, interfere with leucocyte-endothelial interactions. However, differences between efavirenz and nevirapine suggest a specific CV profile for each compound.

HIV protease inhibitors and onset of cardiovascular diseases: a central role for oxidative stress and dysregulation of the ubiquitin-proteasome system

The successful roll-out of highly active antiretroviral therapy (HAART) has extended life expectancy and enhanced the overall well-being of HIV-positive individuals. There are, however, increased concerns regarding HAART-mediated metabolic derangements and its potential risk for cardiovascular diseases (CVD) in the long-term. Here certain classes of antiretroviral drugs such as the HIV protease inhibitors (PIs) are strongly implicated in this process. This article largely focuses on the direct PI-linked development of cardio-metabolic complications, and reviews the inter-linked roles of oxidative stress and the ubiquitin-proteasome system (UPS) as key mediators driving this process. It is proposed that PIs trigger reactive oxygen species (ROS) production that leads to serious downstream consequences such as cell death, impaired mitochondrial function, and UPS dysregulation. Moreover, we advocate that HIV PIs may also directly lower myocardial UPS function. The attenuation of cardiac UPS can initiate transcriptional changes that contribute to perturbed lipid metabolism, thereby fueling a pro-atherogenic milieu. It may also directly alter ionic channels and interfere with electrical signaling in the myocardium. Therefore HIV PI-induced ROS together with a dysfunctional UPS elicit detrimental effects on the cardiovascular system that will eventually result in the onset of heart diseases. Thus while HIV PIs substantially improve life expectancy and quality of life in HIV-positive patients, its longer-term side-effects on the cardiovascular system should lead to a) greater clinical awareness regarding its benefit-harm paradigm, and b) the development and evaluation of novel co-treatment strategies.

Mg supplementation attenuates ritonavir-induced hyperlipidemia, oxidative stress, and cardiac dysfunction in rats

Use of protease inhibitors (PI) in HIV patients is associated with hyperlipidemia and increased risk of coronary heart disease. Chronic systemic and cardiac effects of ritonavir (RTV), a universal PI booster, and Mg supplementation were examined. RTV was administered (75 mg·kg(-1)·day(-1) po) to Lewis × Brown-Norway hybrid (LBNF1) rats for up to 8 wk; significant increases in plasma triglyceride and cholesterol occurred from 8 days to 8 wk. At 5 wk, the expression of selected hepatic genes (CYP7A1, CITED2, G6PC, and ME-1), which are key to lipid catabolism/synthesis, were altered toward lipogenesis. Dietary Mg supplementation (six-fold higher) completely reversed the altered expression of these genes and attenuated both hypertriglyceridemia and hypercholesterolemia. Neutrophils isolated from the RTV-treated rats displayed a three-fold higher basal and a twofold higher stimulated superoxide production; plasma isoprostane and red blood cell (RBC) GSSG levels were elevated two- to three-fold. All oxidative indices were normalized by Mg supplementation. After 5 wk, RTV caused significant decreases in cardiac left ventricular (LV) shortening fraction and LV ejection fraction; mitral valve early/late atrial ventricular filling (E/A) ratio was reduced accompanied by LV posterior wall thinning. Immunohistochemical staining revealed significant white blood cell (WBC) infiltration (5 wk) and prominent fibrosis (8 wk) in the RTV hearts. Mg supplementation attenuated RTV-induced declines in systolic and diastolic (improved mitral valve E/A ratio) function (>70%), lessened LV posterior wall thinning (by 75%), and substantially decreased the pathological markers. The known clinical hyperlipidemia effects of RTV can be mimicked in the LBNF1 rats; in association, systemic oxidative stress and progressive cardiac dysfunction occurred. Remarkably, Mg supplementation alone suppressed RTV-mediated hyperlipidemia, oxidative stress, and cardiac dysfunction.

HIV Tat induces expression of ICAM-1 in HUVECs: implications for miR-221/-222 in HIV-associated cardiomyopathy

Cardiac involvement is a well-documented complication of human immunodeficiency virus-1 (HIV-1) infection. Previous studies have demonstrated increased adhesion of monocytes to human vascular endothelial cells in HIV-infected individuals. HIV Tat protein, which is the transactivator of transcription (Tat), plays a key role in activating endothelial cells. In the present study, we demonstrated that exposure of HUVECs to HIV Tat protein resulted in induced expression of cell adhesion molecules specifically ICAM-1, leading to increased adhesion of monocytes to the endothelium. This effect of Tat was mediated through activation of mitogen-activated protein kinases and downstream transcription factor NF-κB. Increased expression of ICAM-1 was regulated by microRNA (miRNA) miR-221 and to some extent by miR-222, both of which are known to target ICAM-1. Functional inhibition of the respective miRNAs with anti-miR oligonucleotides resulted in induction of ICAM-1 protein in HUVECs. Furthermore, Tat-stimulated regulation of ICAM-1 via miR-221/-222 involved the NF-kB-dependent pathway. Functional implication and specificity of up-regulated ICAM-1 was confirmed using the ICAM-1 neutralizing antibody in the in vitro cell adhesion assays. These findings were further confirmed in vivo using the HIV transgenic (Tg) rats. These animals not only demonstrated increased expression of ICAM-1 mRNA, with a concomitant reduction in the expression of miR-221 in the aorta and heart, but also had increased expression of the ICAM-1 protein that was predominantly in the endothelial cell layer. Taken together, these findings implicate that Tat-mediated induction of ICAM-1 expression plays a critical role in monocyte adhesion observed in HIV-1-associated cardiomyopathies.

Premature and accelerated aging: HIV or HAART?

Highly active antiretroviral therapy (HAART) has significantly increased life expectancy of the human immunodeficiency virus (HIV)-positive population. Nevertheless, the average lifespan of HIV-patients remains shorter compared to uninfected individuals. Immunosenescence, a current explanation for this difference invokes heavily on viral stimulus despite HAART efficiency in viral suppression. We propose here that the premature and accelerated aging of HIV-patients can also be caused by adverse effects of antiretroviral drugs, specifically those that affect the mitochondria. The nucleoside reverse transcriptase inhibitor (NRTI) antiretroviral drug class for instance, is known to cause depletion of mitochondrial DNA via inhibition of the mitochondrial specific DNA polymerase-γ. Besides NRTIs, other antiretroviral drug classes such as protease inhibitors also cause severe mitochondrial damage by increasing oxidative stress and diminishing mitochondrial function. We also discuss important areas for future research and argue in favor of the use of Caenorhabditis elegans as a novel model system for studying these effects.

HIV-1, reactive oxygen species, and vascular complications

Over 1 million people in the United States and 33 million individuals worldwide suffer from HIV/AIDS. Since its discovery, HIV/AIDS has been associated with an increased susceptibility to opportunistic infection due to immune dysfunction. Highly active antiretroviral therapies restore immune function and, as a result, people infected with HIV-1 are living longer. This improved survival of HIV-1 patients has revealed a previously unrecognized risk of developing vascular complications, such as atherosclerosis and pulmonary hypertension. The mechanisms underlying these HIV-associated vascular disorders are poorly understood. However, HIV-induced elevations in reactive oxygen species (ROS), including superoxide and hydrogen peroxide, may contribute to vascular disease development and progression by altering cell function and redox-sensitive signaling pathways. In this review, we summarize the clinical and experimental evidence demonstrating HIV- and HIV antiretroviral therapy-induced alterations in reactive oxygen species and how these effects are likely to contribute to vascular dysfunction and disease.

Relationship between total bilirubin and endothelial function, inflammation and oxidative stress in HIV-infected adults on stable antiretroviral therapy

OBJECTIVES

Enhanced inflammation is evident in HIV infection, even with virological suppression. Outside HIV infection, studies show an independent association between higher total bilirubin and better endothelial function as well as a lower prevalence of coronary heart disease, possibly as a consequence of the anti-inflammatory and antioxidant effect of bilirubin. The aim of this study was to determine whether such an association exists in HIV-infected individuals.

METHODS

A cross-sectional study was performed in HIV-1-infected adults on stable antiretroviral therapy (ART) to determine if a relationship exists between total bilirubin and endothelial function [flow-mediated dilation (FMD) of the brachial artery], inflammation [interleukin-6 (IL-6), soluble tumour necrosis factor receptors, C-reactive protein, and adhesion molecules], coagulation markers (fibrinogen and D-dimer) and oxidative stress (F (2) -isoprostanes). Endpoints were compared based on total bilirubin levels and atazanavir status using distributionally appropriate, two-sample tests. Correlation coefficients were determined between total bilirubin and endpoints. Linear regression was used to model the relationship between total bilirubin (and atazanavir status) and FMD.

RESULTS

A total of 98 adults were included in the study. Total bilirubin was higher in the atazanavir group when compared to the non-atazanavir group [median (interquartile range) 1.8 (1.1-2.6) vs. 0.6 (0.4-1.4) mg/dL; P < 0.01] as were insulin, the homeostasis model assessment of insulin resistance (HOMA-IR) and fibrinogen. Total bilirubin was positively correlated with fibrinogen and was not correlated with other outcomes. After adjustment, neither total bilirubin nor atazanavir status was associated with FMD.

CONCLUSIONS

In virologically suppressed, HIV-infected adults on stable ART, neither total bilirubin nor atazanavir use was associated with improved endothelial function as measured using FMD, inflammation or oxidative stress as measured using biomarkers.

Metabolic abnormalities and viral replication are associated with biomarkers of vascular dysfunction in HIV-infected children

OBJECTIVES

HIV-infected children may be at risk for premature cardiovascular disease. We compared levels of biomarkers of vascular dysfunction in HIV-infected children (with and without hyperlipidaemia) with those in HIV-exposed, uninfected (HEU) children enrolled in the Pediatric HIV/AIDS Cohort Study (PHACS), and determined factors associated with these biomarkers.

METHODS

A prospective cohort study was carried out. Biomarkers of inflammation [C-reactive protein (CRP), interleukin-6 (IL-6) and monocyte chemoattractant protein-1 (MCP1)], coagulant dysfunction (fibrinogen and P-selectin), endothelial dysfunction [soluble intracellular cell adhesion molecule-1 (sICAM), soluble vascular cell adhesion molecule-1 (sVCAM) and E-selectin], and metabolic dysfunction (adiponectin) were measured in 226 HIV-infected and 140 HEU children. Anthropometry, body composition, lipids, glucose, insulin, HIV disease severity, and antiretroviral therapy were recorded.

RESULTS

The median ages of the children were 12.3 years in the HIV-infected group and 10.1 years in the HEU group. Body mass index (BMI) z-scores, waist and hip circumferences, and percentage body fat were lower in the HIV-infected children. Total and non-high-density lipoprotein (HDL) cholesterol and triglycerides were higher in HIV-infected children. HIV-infected children also had higher MCP-1, fibrinogen, sICAM and sVCAM levels. In multivariable analyses in the HIV-infected children alone, BMI z-score was associated with higher CRP and fibrinogen, but lower MCP-1 and sVCAM. Unfavourable lipid profiles were positively associated with IL-6, MCP-1, fibrinogen, and P- and E-selectin, whereas increased HIV viral load was associated with markers of inflammation (MCP-1 and CRP) and endothelial dysfunction (sICAM and sVCAM).

CONCLUSIONS

HIV-infected children have higher levels of biomarkers of vascular dysfunction than do HEU children. Risk factors associated with higher biomarkers include unfavourable lipid levels and active HIV replication.

Role of Drp1, a key mitochondrial fission protein, in neuropathic pain

While oxidative stress has been implicated in small-fiber painful peripheral neuropathies, antioxidants are only partially effective to treat patients. We have tested the hypothesis that Drp1 (dynamin-related protein 1), a GTPase that catalyzes the process of mitochondrial fission, which is a mechanism central for the effect and production of reactive oxygen species (ROS), plays a central role in these neuropathic pain syndromes. Intrathecal administration of oligodeoxynucleotide antisense against Drp1 produced a decrease in its expression in peripheral nerve and markedly attenuated neuropathic mechanical hyperalgesia caused by HIV/AIDS antiretroviral [ddC (2',3'-dideoxycytidine)] and anticancer (oxaliplatin) chemotherapy in male Sprague Dawley rats. To confirm the role of Drp1 in these models of neuropathic pain, as well as to demonstrate its contribution at the site of sensory transduction, we injected a highly selective Drp1 inhibitor, mdivi-1, at the site of nociceptive testing on the dorsum of the rat's hindpaw. mdivi-1 attenuated both forms of neuropathic pain. To evaluate the role of Drp1 in hyperalgesia induced by ROS, we demonstrated that intradermal hydrogen peroxide produced dose-dependent hyperalgesia that was inhibited by mdivi-1. Finally, mechanical hyperalgesia induced by diverse pronociceptive mediators involved in inflammatory and neuropathic pain-tumor necrosis factor α, glial-derived neurotrophic factor, and nitric oxide-was also inhibited by mdivi-1. These studies provide support for a substantial role of mitochondrial fission in preclinical models of inflammatory and neuropathic pain.

Highly active antiretroviral therapy drug combination induces oxidative stress and mitochondrial dysfunction in immortalized human blood-brain barrier endothelial cells

The era of highly active antiretroviral therapy (HAART) has controlled AIDS and its related disorders considerably; however, the prevalence of HIV-1-associated neurocognitive disorders has been on the rise in the post-HAART era. In view of these developments, we investigated whether a HAART drug combination of 3'-azido-2',3'-deoxythymidine (AZT) and indinavir (IDV) can alter the functionality of the blood-brain barrier (BBB) endothelial cells, thereby exacerbating this condition. The viability of hCMEC/D3 cells (in vitro model of BBB) that were exposed to these drugs was significantly reduced after 72h treatment, in a dose-dependent manner. Reactive oxygen species were highly elevated after the exposure, indicating that mechanisms that induce oxidative stress were involved. Measures of oxidative stress parameters, such as glutathione and malondialdehyde, were altered in the treated groups. Loss of mitochondrial membrane potential, as assessed by fluorescence microscopy and decreased levels of ATP, indicated that cytotoxicity was mediated through mitochondrial dysfunction. Furthermore, AZT+IDV treatment caused apoptosis in endothelial cells, as assessed by the expression of cytochrome c and procaspase-3 proteins. Pretreatment with the thiol antioxidant N-acetylcysteine amide reversed some of the pro-oxidant effects of AZT+IDV. Results from our in vitro studies indicate that the AZT+IDV combination may affect the BBB in HIV-infected individuals treated with HAART drugs.

Myocarditis in CD8-depleted SIV-infected rhesus macaques after short-term dual therapy with nucleoside and nucleotide reverse transcriptase inhibitors

BACKGROUND

Although highly active antiretroviral therapy (HAART) has dramatically reduced the morbidity and mortality associated with HIV infection, a number of antiretroviral toxicities have been described, including myocardial toxicity resulting from the use of nucleotide and nucleoside reverse transcriptase inhibitors (NRTIs). Current treatment guidelines recommend the use of HAART regimens containing two NRTIs for initial therapy of HIV-1 positive individuals; however, potential cardiotoxicity resulting from treatment with multiple NRTIs has not been addressed.

METHODOLOGY/PRINCIPAL FINDINGS

We examined myocardial tissue from twelve CD8 lymphocyte-depleted adult rhesus macaques, including eight animals infected with simian immunodeficiency virus, four of which received combined antiretroviral therapy (CART) consisting of two NRTIs [(9-R-2-Phosphonomethoxypropyl Adenine) (PMPA) and (+/-)-beta-2',3'-dideoxy-5-fluoro-3'-thiacytidine (RCV)] for 28 days. Multifocal infiltrates of mononuclear inflammatory cells were present in the myocardium of all macaques that received CART, but not untreated SIV-positive animals or SIV-negative controls. Macrophages were the predominant inflammatory cells within lesions, as shown by immunoreactivity for the macrophage markers Iba1 and CD68. Heart specimens from monkeys that received CART had significantly lower virus burdens than untreated animals (p<0.05), but significantly greater quantities of TNF-α mRNA than either SIV-positive untreated animals or uninfected controls (p<0.05). Interferon-γ (IFN-γ), IL-1β and CXCL11 mRNA were upregulated in heart tissue from SIV-positive monkeys, independent of antiretroviral treatment, but CXCL9 mRNA was only upregulated in heart tissue from macaques that received CART.

CONCLUSIONS/SIGNIFICANCE

These results suggest that short-term treatment with multiple NRTIs may be associated with myocarditis, and demonstrate that the CD8-depleted SIV-positive rhesus monkey is a useful model for studying the cardiotoxic effects of combined antiretroviral therapy in the setting of immunodeficiency virus infection.

Premature Senescence of Vascular Cells Is Induced by HIV Protease Inhibitors

Objective— To determine whether and how protease inhibitors (PIs) could affect vascular aging.

Methods and Results— HIV therapy with PIs is associated with an increased risk of premature cardiovascular disease. The effect of ritonavir and a combination of lopinavir and ritonavir (for 30 days) on senescence, oxidative stress, and inflammation was evaluated in human coronary artery endothelial cells (HCAECs). These HCAECs were either cotreated or not cotreated with pravastatin or farnesyl transferase inhibitor (FTI)-277 or with 2 antioxidants (manganese [III] tetrakis [4-benzoic acid] porphyrin [MnTBAP] and N-acetyl cysteine). Senescence markers were evaluated in peripheral blood mononuclear cells (PBMCs) from HIV-infected patients under PI treatment. PIs induced senescence markers, prelamin A accumulation, oxidative stress, and inflammation in HCAECs. Senescence markers and prelamin A were also observed in PBMCs from HIV-infected patients under ritonavir-boosted PIs. Pravastatin, FTI-277, and antioxidants improved PI adverse effects in HCAECs. Senescence markers were lower in PBMCs from PI-treated patients cotreated with statins.

Conclusion— PIs triggered premature senescence in endothelial cells by a mechanism involving prelamin A accumulation. Accordingly, circulating cells from HIV-infected patients receiving PI therapy expressed senescence markers and prelamin A. Statin was associated with improved senescence in endothelial cells and patient PBMCs. Thus, PIs might promote vascular senescence in HIV-infected patients; and statins might exert beneficial effects in these patients.

Switching antiretroviral therapy to minimize metabolic complications

Advances in HIV therapy have made living with HIV for decades a reality for many patients. However, antiretroviral therapy has been associated with multiple long-term complications, including dyslipidemia, fat redistribution, insulin resistance and increased cardiovascular risk. As newer agents with improved metabolic profiles have become available, there is growing interest in the safety and efficacy of switching ART as a strategy to reduce long-term complications. This article reviews recently published data on switching ART to minimize the contributions of specific agents to these complications.

Biomarkers of vascular dysfunction in children infected with human immunodeficiency virus-1

BACKGROUND

: We compared biomarkers of vascular dysfunction among HIV-infected children to a demographically similar group of uninfected children and determined factors associated with these biomarkers.

METHODS AND RESULTS

: We measured several biomarkers of vascular dysfunction: C-reactive protein (CRP), interleukin-6 (IL-6), and monocyte chemoattractant protein -1 (MCP-1) (inflammation); fibrinogen and P-selectin (coagulant dysfunction); soluble intracellular cell adhesion molecule-1 (sICAM), soluble vascular cell adhesion molecule-1 (sVCAM), and E-selectin (endothelial dysfunction); and leptin (metabolic dysfunction). Anthropometry, body composition, CD4%, HIV viral load, and antiretroviral therapy were recorded. Mean age was 14.8 years (106 HIV-infected children) and 12.3 years (55 control children). Sex and body mass index Z scores were similar. Infected children had higher sICAM, sVCAM, MCP-1, IL-6, and fibrinogen levels. E-selectin (P = 0.07), and CRP (P = 0.08) trended to be greater in the HIV group, yet leptin and P-selectin were similar. In multivariable analyses in the HIV-infected children alone, each 1 standard deviation increase in waist to hip ratio was associated with increases in sICAM (17%), MCP-1 (19%), IL6 (18%), and CRP (59%). CD4% was inversely associated with sVCAM, MCP-1, IL6, fibrinogen, and CRP.

CONCLUSIONS

: HIV-infected children have higher levels of biomarkers of vascular dysfunction than healthy children. Risk factors associated with these biomarkers include higher waist to hip ratios and HIV disease severity.

Reactive nitrogen and oxygen species, and iron sequestration contribute to macrophage-mediated control of Encephalitozoon cuniculi (Phylum Microsporidia) infection in vitro and in vivo

Encephalitozoon cuniculi (Phylum Microsporidia) infects a wide range of mammals, and replicates within resting macrophages. Activated macrophages, conversely, inhibit replication and destroy intracellular organisms. These studies were performed to assess mechanisms of innate immune responses expressed by macrophages to control E. cuniculi infection. Addition of reactive oxygen and nitrogen species inhibitors to activated murine peritoneal macrophages statistically significantly, rescued E. cuniculi infection ex vivo. Mice deficient in reactive oxygen species, reactive nitrogen species, or both survived ip inoculation of E. cuniculi, but carried significantly higher peritoneal parasite burdens than wild-type mice at 1 and 2 weeks post inoculation. Infected peritoneal macrophages could still be identified 4 weeks post inoculation in mice deficient in reactive nitrogen species. L-tryptophan supplementation of activated murine peritoneal macrophage cultures ex vivo failed to rescue microsporidia infection. Addition of ferric citrate to supplement iron, however, did significantly rescue E. cuniculi infection in activated macrophages and further increased parasite replication in non-activated macrophages over non-treated resting control macrophages. These results demonstrate the contribution of reactive oxygen and nitrogen species, as well as iron sequestration, to innate immune responses expressed by macrophages to control E. cuniculi infection.

Development of a novel self-microemulsifying drug delivery system for reducing HIV protease inhibitor-induced intestinal epithelial barrier dysfunction

The development of HIV protease inhibitors (PIs) has been one of the most significant advances of the past decade in controlling HIV infection. Unfortunately, the benefits of HIV PIs are compromised by serious side effects. One of the most frequent and deleterious side effects of HIV PIs is severe gastrointestinal (GI) disorders including mucosal erosions, epithelial barrier dysfunction, and leak-flux diarrhea, which occurs in 16-62% of patients on HIV PIs. Although the underlying mechanisms behind HIV PI-associated serious adverse side effects remain to be identified, our recent studies have shown that activation of endoplasmic reticulum (ER) stress response plays a critical role in HIV PI-induced GI complications. The objective of this study was to develop a novel self-microemulsifying drug delivery system (SMEDDS) using various antioxidants as surfactants and cosurfactants to reduce the GI side effects of the most commonly used HIV PI, ritonavir. The biological activities of this SMSDDS of ritonavir were compared with that of Norvir, which is currently used in the clinic. Rat normal intestinal epithelial cells (IEC-6) and mouse Raw 264.7 macrophages were used to examine the effect of new SMEDDS of ritonavir on activation of ER stress and oxidative stress. Sprague-Dawley rats and C57/BL6 mice were used for pharmacokinetic studies and in vivo studies. The intracellular and plasma drug concentrations were determined by HPLC analysis. Activation of ER stress was detected by Western blot analysis and secreted alkaline phosphatase (SEAP) reporter assay. Reactive oxygen species (ROS) was measured using dichlorodihydrofluorescein diacetate as a probe. Cell viability was determined by Roche's cell proliferation reagent WST-1. Protein levels of inflammatory cytokines (TNF-alpha and IL-6) were determined by enzyme-linked immunosorbent assays (ELISA). The intestinal permeability was assessed by luminal enteral administration of fluorescein isothiocyanate conjugated dextran (FITC-dextran, 4 kDa). The pathologic changes in intestine were determined by histological examination. The results indicated that incorporation of antioxidants in this new SMEDDS not only significantly reduced ritonavir-induced ER stress activation, ROS production and apoptosis in intestinal epithelial cells and macrophages, but also improved the solubility, stability and bioavailability of ritonavir, and significantly reduced ritonavir-induced disruption of intestinal barrier function in vivo. In conclusion, this new SMEDDS of ritonavir has less GI side effects compared to Norvir. This new SMEDDS can be used for other HIV PIs and any insoluble antiviral drug with serious GI side effects.