Oxidative stress and HIV infection: target pathways for novel therapies?

Tricyclodecan-9-yl-Xanthogenate (D609): Mechanism of Action and Pharmacological Applications

Tricyclodecan-9-yl xanthogenate (D609) is a synthetic tricyclic compound possessing a xanthate group. This xanthogenate compound is known for its diverse pharmacological properties. Over the last three decades, many studies have reported the biological activities of D609, including antioxidant, antiapoptotic, anticholinergic, anti-tumor, anti-inflammatory, anti-viral, anti-proliferative, and neuroprotective activities. Its mechanism of action is extensively attributed to its ability to cause the competitive inhibition of phosphatidylcholine (PC)-specific phospholipase C (PC-PLC) and sphingomyelin synthase (SMS). The inhibition of PCPLC or SMS affects secondary messengers with a lipidic nature, i.e., 1,2-diacylglycerol (DAG) and ceramide. Various in vitro/in vivo studies suggest that PCPLC and SMS inhibition regulate the cell cycle, block cellular proliferation, and induce differentiation. D609 acts as a pro-inflammatory cytokine antagonist and diminishes Aβ-stimulated toxicity. PCPLC enzymatic activity essentially requires Zn²⁺, and D609 might act as a potential chelator of Zn²⁺, thereby blocking PCPLC enzymatic activity. D609 also demonstrates promising results in reducing atherosclerotic plaque formation, post-stroke cerebral infarction, and cancer progression. The present compilation provides a comprehensive mechanistic insight into D609, including its chemistry, mechanism of action, and regulation of various pharmacological activities.

Redox imbalance is related to HIV and pregnancy

Redox imbalance may compromise the homeostasis of physiological processes indispensable to gestational development in HIV-infected women. The present study aims to evaluate markers of the redox system in the development of pregnancy of these women. HIV-positive pregnant women, HIV-negative pregnant women and non-pregnant were studied. Redox markers superoxide dismutase (SOD), catalase (CAT), protein carbonylation and malondialdehyde (MDA) were assessed at first or second trimester, third trimester and postpartum from pregnant and from non-pregnant women. According to the longitudinal analysis model, CAT activity was increased in the postpartum in HIV-positive women and before delivery in HIV-negative women. Increased carbonylation was observed in the pre-delivery period of HIV-negative pregnant women and MDA concentrations were higher in HIV-positive pregnant women compared to those non-infected by HIV at all times. According to the factorial model, higher SOD and CAT activities were observed in HIV-positive women in the initial months of pregnancy and in non-pregnant women. Carbonylation at third trimester was more evident in HIV-negative pregnant women. MDA levels were higher in HIV-positive pregnant women. Increased oxidative stress may occur in HIV-infected pregnant women. Nevertheless, the HIV virus is not solely responsible for this process; instead, mechanisms inherent to the pregnancy seem to play a role in this imbalance.

The Role of Multimicronutrient Supplementation in Pediatric HIV Management in Nigeria: A Randomized Controlled Study

BACKGROUND

We aimed to compare the immunologic and hematologic effects of 3 multimicronutrient supplements in human immunodeficiency virus-positive children in Lagos, Nigeria.

METHODS

This double-blind, randomized controlled study included 190 children, aged 5-12 years, in Lagos, Nigeria. Sixty-four, 63, and 63 participants were assigned to multimicronutrient group A, B, or C, respectively, for 6 months. Supplements A, B, and C contained 7 micronutrients at the recommended daily allowance (RDA) (comparable to standard-of-care multivitamin), 22 micronutrients at the RDA, and 22 micronutrients at 3 times the recommended daily allowance (3RDA), respectively. Using paired sample t tests and factorial repeat-measures analysis of variance (ANOVA), within- and between-group changes in CD4 count and hemoglobin levels were evaluated after 6 months.

RESULTS

After 6 months of supplementation, paired-sample t test showed that CD4 cell count did not significantly differ from baseline for all 3 groups. Between-subject effect also did not significantly differ in the 3 groups after 6 months (factorial repeat-measures ANOVA (F [degrees of freedom {df} = 2, 187] = 0.846; P = .436; partial η 2 = 0.009). Hemoglobin levels were significantly increased after supplementation in all 3 supplement groups. Increases were not significantly different between groups (factorial repeat-measures ANOVA (F [df = 2, 187] = 0.549; P = .591; partial η 2 = 0.006).

CONCLUSIONS

Equivalent effects were observed. After 6 months of supplementation, mean CD4 count was not significantly different between groups. Hemoglobin concentration was significantly increased in all 3 groups, but increase did not differ between groups.

CLINICAL TRIALS REGISTRATION

NCT02552602.

Genomic instability in people living with HIV

The increased life expectancy of people living with HIV (PLWH) receiving antiretroviral treatment (ART) has transformed HIV infection into a chronic disease. However, patients may be at risk of accelerated aging and the accumulation of cellular damage, which may trigger the development of cancer. We evaluated genomic instability in HIV-positive individuals with different viral loads receiving antiretroviral treatment (ART) and in HIV ART-naïve individuals. We included 67 participants divided into four groups: group 1 (n = 24) HIV patients receiving reverse-transcriptase inhibitors (tenofovir/ emtricitabine/ efavirenz and abacavir/ lamivudine/ efavirenz), group 2 (n = 22) HIV patients receiving protease inhibitors combined with other antiretroviral drugs (tenofovir/ emtricitabine with ritonavir/ atazanavir or lopinavir/ ritonavir, and darunavir/ ritonavir/ raltegravir), group 3 (n = 13) HIV ART-naïve patients, and group 4 (n = 8) healthy individuals (controls). Nuclear abnormalities in buccal mucosal samples (micronuclei, binucleated cells, nuclear buds, karyorrhexis, karyolysis, and pyknosis) were quantified. Simultaneously, blood samples were taken to quantify CD4+, CD8+, and HIV viral load. There was a significant age difference between HIV ART-naïve patients and receiving ART groups. Infection time was longer in HIV patients with ART than in ART-naïve patients. There were no differences in sex, smoking, alcohol consumption, or number of micronucleated cells between the study groups. We found higher frequencies of binucleated cells and nuclear buds in HIV patients, HIV ART-naïve, and HIV ART patients compared to the control group. We found a positive correlation between nuclear buds and CD4/CD8 ratio in the HIV ART-naïve group. In conclusion, PLWH showed increased genomic instability. The CD4/CD8 ratio affects the numbers of nuclear buds and binucleated cells. These findings are pertinent to mechanisms of damage and possible strategies to mitigate carcinogenesis in PLWH.

Extracellular Vesicles in Smoking-Mediated HIV Pathogenesis and their Potential Role in Biomarker Discovery and Therapeutic Interventions

In the last two decades, the mortality rate in people living with HIV/AIDS (PLWHA) has decreased significantly, resulting in an almost normal longevity in this population. However, a large portion of this population still endures a poor quality of life, mostly due to an increased inclination for substance abuse, including tobacco smoking. The prevalence of smoking in PLWHA is consistently higher than in HIV negative persons. A predisposition to cigarette smoking in the setting of HIV potentially leads to exacerbated HIV replication and a higher risk for developing neurocognitive and other CNS disorders. Oxidative stress and inflammation have been identified as mechanistic pathways in smoking-mediated HIV pathogenesis and HIV-associated neuropathogenesis. Extracellular vesicles (EVs), packaged with oxidative stress and inflammatory agents, show promise in understanding the underlying mechanisms of smoking-induced HIV pathogenesis via cell-cell interactions. This review focuses on recent advances in the field of EVs with an emphasis on smoking-mediated HIV pathogenesis and HIV-associated neuropathogenesis. This review also provides an overview of the potential applications of EVs in developing novel therapeutic carriers for the treatment of HIV-infected individuals who smoke, and in the discovery of novel biomarkers that are associated with HIV-smoking interactions in the CNS.

Dimethyl Fumarate Prevents HIV-Induced Lysosomal Dysfunction and Cathepsin B Release from Macrophages

HIV-associated neurocognitive disorders (HAND) are prevalent despite combined antiretroviral therapy, affecting nearly half of HIV-infected patients worldwide. During HIV infection of macrophages secretion of the lysosomal protein, cathepsin B, is increased. Secreted cathepsin B has been shown to induce neurotoxicity. Oxidative stress is increased in HIV-infected patients, while antioxidants are decreased in monocytes from patients with HIV-associated dementia (HAD). Dimethyl fumarate (DMF), an antioxidant, has been reported to decrease HIV replication and neurotoxicity mediated by HIV-infected macrophages. Thus, we hypothesized that DMF will decrease cathepsin B release from HIV-infected macrophages by preventing oxidative stress and enhancing lysosomal function. Monocyte-derived macrophages (MDM) were isolated from healthy donors, inoculated with HIV-1_ADA, and treated with DMF following virus removal. After 12 days post-infection, HIV-1 p24 and total cathepsin B levels were measured from HIV-infected MDM supernatants using ELISA; intracellular reactive oxygen and nitrogen species (ROS/RNS) were measured from MDM lysates, and functional lysosomes were assessed using a pH-dependent lysosomal dye. Neurons were incubated with serum-free conditioned media from DMF-treated MDM and neurotoxicity was determined using TUNEL assay. Results indicate that DMF reduced HIV-1 replication and cathepsin B secretion from HIV-infected macrophages in a dose-dependent manner. Also, DMF decreased intracellular ROS/RNS levels, and prevented HIV-induced lysosomal dysfunction and neuronal apoptosis. In conclusion, the improvement in lysosomal function with DMF treatment may represent the possible mechanism to reduce HIV-1 replication and cathepsin B secretion. DMF represents a potential therapeutic strategy against HAND.

Viral, Serological, and Antioxidant Investigations of Equine Rhinitis A Virus in Serum and Nasal Swabs of Commercially Used Horses in Poland

Background

Equine rhinitis A virus (ERAV) is considered to be an important pathogen in horses, but relatively few studies are available.

Aims

The purpose of this study was to verify ERAV seroprevalence in selected horses in Poland, in addition to correlation between ERAV and age and sex of analysed animals and the antioxidant status.

Methods

The material collected from clinically healthy horses was tested using the VNT (353 serum samples) and virus isolation method (44 nasal swabs). 27 serum samples with antibody titers between 0 and ≥1 : 2048 were chosen for further analysis. The study was conducted in group 1 (ERAV titer ≤ 64) and group 2 (ERAV titer > 64).

Results

Seroneutralisation tests showed positive results in 72% of serum samples. No significant correlation between ERAV seropositive results and selected biochemical indicators was observed. Group 2 had statistically higher concentrations of SOD and CuZnSOD than the analysed group 1.

Conclusions

ERAV was not detected in the nasal swab samples. Antioxidant parameters did not significantly vary between horses of different breed, sex, or age. The ERAV virus had an impact on plasma total SOD and Cu/Zn SOD activity in horses in early stages of convalescence.

HIV-1 Tat protein induces DNA damage in human peripheral blood B-lymphocytes via mitochondrial ROS production

Human immunodeficiency virus (HIV) infection is associated with B-cell malignancies in patients though HIV-1 is not able to infect B-cells. The rate of B-cell lymphomas in HIV-infected individuals remains high even under the combined antiretroviral therapy (cART) that reconstitutes the immune function. Thus, the contribution of HIV-1 to B-cell oncogenesis remains enigmatic. HIV-1 induces oxidative stress and DNA damage in infected cells via multiple mechanisms, including viral Tat protein. We have detected elevated levels of reactive oxygen species (ROS) and DNA damage in B-cells of HIV-infected individuals. As Tat is present in blood of infected individuals and is able to transduce cells, we hypothesized that it could induce oxidative DNA damage in B-cells promoting genetic instability and malignant transformation. Indeed, incubation of B-cells isolated from healthy donors with purified Tat protein led to oxidative stress, a decrease in the glutathione (GSH) levels, DNA damage and appearance of chromosomal aberrations. The effects of Tat relied on its transcriptional activity and were mediated by NF-κB activation. Tat stimulated oxidative stress in B-cells mostly via mitochondrial ROS production which depended on the reverse electron flow in Complex I of respiratory chain. We propose that Tat-induced oxidative stress, DNA damage and chromosomal aberrations are novel oncogenic factors favoring B-cell lymphomas in HIV-1 infected individuals.

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B-cells of HIV-infected individuals exhibit elevated levels of oxidative stress, DNA damage and chromosomal aberrations.

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Purified HIV-1 Tat protein reproduces this effect and induces oxidative stress and DNA damage in B-cells.

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HIV-1 Tat induces mitochondrial oxidative stress and activates NF-kB in B-cells.

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This condition increases the risk of developing chromosomal abnormalities and translocations.

A Study on Gene Expression Profile of Endogenous Antioxidant Enzymes: CAT, MnSOD and GPx in Dengue Patients

Dengue is an arthropod-borne threat among tropical countries. Currently no effective means to treat the virus or to predict which patient will develop the severe form of the disease. Recently the relationship between oxidative/antioxidative response and dengue pathogenesis was suggested. Based on this the present study has analysed the expression of endogenous antioxidant genes: Catalase (CAT), Superoxide dismutase (MnSOD) and Glutathione peroxidase in patients with dengue compared to other febrile illness (OFI) and healthy controls. The study enrolled 88 dengue confirmed patients comprising 56 were patients with non-severe dengue, and 32 were severe dengue cases, 31 were patients with OFI, and 63 healthy controls were also involved. Peripheral blood mononuclear cells isolated from patients and controls during the day of admission and from the available cases on the day of defervescence were used to estimate the transcript levels by quantitative PCR. The expression levels of all the three genes were found to be down-regulated throughout the course of dengue infection (p < 0.05) and OFI cases compared to healthy controls. Within dengue group, no significant difference was observed in any of the parameters between severe and non-severe cases. Interestingly, a significant down-regulation of MnSOD expression was recorded in secondary dengue infection compared to primary during admission (p < 0.05). It was found that all the down-regulated study genes have positively correlated in all dengue cases during the day of admission (p < 0.01). But during defervescence, the same was found only between CAT and MnSOD. Down-regulated endogenous antioxidant enzymes during dengue infection could be the possible rationale of oxidative stress reported in dengue disease earlier. The present study markers could not distinguish dengue from OFI cases and severe from non-severe dengue cases. Mechanism of down-regulation has to be explored further which will pave the way for the therapeutic target in dengue disease.

Increased oxidative stress condition found in different stages of HIV disease in patients undergoing antiretroviral therapy in Umuahia (Nigeria)

CONTEXT

Effective diagnostic tools for management of HIV disease progression in Sub-Saharan Africa is inadequate considering the endemic nature of the infection in the region.

OBJECTIVE

To elucidate the clinical implication of oxidative stress (measured as Malondialdehyde, MDA) as additional biomarker of HIV disease progression and its implication in HIV clinical management.

MATERIALS AND METHODS

A total of 250 individuals were recruited for the study. FACScan cytometry and spectrophotometric methods were employed in assessing T-lymphocytes (CD3, CD4, CD8) and MDA respectively.

RESULTS

MDA concentration increased significantly (P < 0.05) in highly active antiretroviral therapy (HAART) subjects by 12.72% in category 1, 9.75% in III and in category II (4.63%) on comparison with non-HAART subjects. In subjects taking HAART, 22.2%, 56.3%, and 22.2% were found to be in category I, II and III, respectively, with a corresponding non-HAART values of 15.6%, 45.6% and 38.9%. However, Spearman's rank correlation (P < 0.001) statistics of MDA and HIV categories showed a negative correlation in all the categories (I, II and III).

DISCUSSION AND CONCLUSION

These findings suggest that MDA may be an additional clinical factor in assessing progression of HIV disease; however, necessary fortification of regimen with antioxidant may help reduce the high MDA concentration in the disease progression of the infection.

Phytochemical studies and antioxidant activity of two South African medicinal plants traditionally used for the management of opportunistic fungal infections in HIV/AIDS patients

Background

It has been observed that perturbations in the antioxidant defense systems, and consequently redox imbalance, are present in many tissues of HIV-infected patients. Hence, the exogenous supply of antioxidants, as natural compounds that scavenge free radicals, might represent an important additional strategy for the treatment of HIV infection. The aim of this study was therefore to analyse the phytochemical constituents and antioxidant potential of Gasteria bicolor Haw and Pittosporum viridiflorum Sims., two South African plants traditionally used for the management of opportunistic fungal infections (OFIs) in AIDS patients.

Methods

The in vitro antioxidant properties of the two plants were screened through DPPH (1,1-diphenyl-2-picrylhydrazyl), NO (nitric oxide), H₂O₂ (hydrogen peroxide) radical scavenging effects and reducing power assays. Phytochemical studies were done by spectrophotometric techniques.

Results

There were no significant differences in the flavonoid and proanthocyanidins contents between the leaves and bark extracts of Gasteria bicolor and Pittosporum viridiflorum respectively, while the total phenolic content of the bark extract of P. viridiflorum was significantly higher than that of G. bicolor leaf. The acetone extracts of both plants indicated strong antioxidant activities.

Conclusion

The results from this study indicate that the leaves and stem extracts of Gasteria bicolor and Pittosporum viridiflorum respectively possess antioxidant properties and could serve as free radical inhibitors, acting possibly as primary antioxidants. Since reactive oxygen species are thought to be associated with the pathogenesis of AIDS, and HIV-infected individuals often have impaired antioxidant defenses, the inhibitory effect of the extracts on free radicals may partially justify the traditional use of these plants in the management of OFIs in HIV patients in South Africa.

Oxidant-antioxidant imbalance in horses infected with equine infectious anaemia virus

This study assesses the impact of equine infectious anaemia virus (EIAV) infection on the oxidant/antioxidant equilibrium of horses. Blood samples from 96 Romanian horses aged 1-25 years, were divided into different groups according to their EIAV-infection status, age, and time post-seroconversion. The effect of infection on oxidative stress was estimated by measuring enzymatic antioxidants (superoxide dismutase [SOD], glutathione peroxidase [GPx] and catalase), non-enzymatic antioxidants (uric acid and carotenoids), and lipid peroxidation (malondialdehyde [MDA]). Infection modified the oxidant/antioxidant equilibrium in the horses, influencing GPx and uric acid levels (P<0.05). Time post-seroconversion also contributed to oxidative stress imbalance, exhibiting a significant influence on both SOD and MDA concentrations in the blood (P<0.05). Animal age did not have a significant influence on oxidative stress. Recently infected horses (<1 year following seroconversion), and horses >5 years old, represented the most vulnerable category in terms of oxidative stress, followed by recently infected animals <5 years old. The results of this study are novel in implicating EIAV infection in the development of oxidative stress in horses.