Human Immunodeficiency Virus Viral Replication Research Articles

Prevalence Of Undernutrition And Associated Factors Among Adults Receiving First-Line Antiretroviral Treatment In Public Health Facilities Of Arba Minch Town, Southern Ethiopia.

IntroductionAccess to antiretroviral drugs for all infected persons in need is a global health priority. The primary goals of initiating antiretroviral drugs are to suppress human immunodeficiency virus viral replication and to restore immune function. However, adequate nutrition is necessary to manage opportunistic infections and to maintain the immune system. Therefore, this study aimed to determine the recent prevalence of undernutrition and associated factors among HIV patients receiving first-line antiretroviral therapy in public health facilities of Arba Minch town, Gamo zone, Southern Ethiopia.MethodsInstitution-based cross-sectional study was used among 333 adult patients receiving first-line antiretroviral therapy at public health facilities of Arba Minch town. A simple random sampling technique was used to select the study subjects. Data were collected through interviewer-administered questionnaires. Binary and multivariable logistic regression analyses were used to identify factors associated with undernutrition. A p-value <0.05 with a 95% confidence level was used to declare statistical significance.ResultsThe overall prevalence of undernutrition among adult patients receiving first-line antiretroviral therapy is 23.72% (95% CI: 19.13–28.27%). Current substance use (AOR=1.83, 95% CI:1.09–3.08), duration on antiretroviral therapy (AOR=1.87, 95% CI:1.06–3.30), not taking cotrimoxazole preventive therapy (AOR=2.09, 95% CI:1.15–3.82), advanced WHO clinical stages (AOR=5.1, 95% CI: 2.9–7.7), CD4 count less than 350 cell/mm3 (AOR=1.83, 95% CI: 1.09–3.05) and active tuberculosis (AOR=1.89, 95% CI: 1.02–3.53) were factors significantly associated with undernutrition among respondents who were enrolled on first-line antiretroviral therapy.ConclusionThis study shows that the prevalence of undernutrition was high among adult patients on first-line antiretroviral therapy. Therefore, this finding shows the need to implement nutrition programs to improve the nutritional status of adults living with HIV in the study area. The interventions should emphasise those patients who use the substance, who are in advanced WHO clinical stage and have active tuberculosis. Besides, emphasis should be given for patients to undertake cotrimoxazole preventive therapy and to regularly follow their CD4 count.

Molecular dissection of an inhibitor targeting the HIV integrase dependent preintegration complex nuclear import.

Human immunodeficiency virus (HIV) continues to be a major contributor to morbidity and mortality worldwide, particularly in developing nations where high cost and logistical issues severely limit the use of current HIV therapeutics. This, combined HIV's high propensity to develop resistance, means that new antiviral agents against novel targets are still urgently required. We previously identified novel anti‐HIV agents directed against the nuclear import of the HIV integrase (IN) protein, which plays critical roles in the HIV lifecycle inside the cell nucleus, as well as in transporting the HIV preintegration complex (PIC) into the nucleus. Here we investigate the structure activity relationship of a series of these compounds for the first time, including a newly identified anti‐IN compound, budesonide, showing that the extent of binding to the IN core domain correlates directly with the ability of the compound to inhibit IN nuclear transport in a permeabilised cell system. Importantly, compounds that inhibited the nuclear transport of IN were found to significantly decrease HIV viral replication, even in a dividing cell system. Significantly, budesonide or its analogue flunisolide, were able to effect a significant reduction in the presence of specific nuclear forms of the HIV DNA (2‐LTR circles), suggesting that the inhibitors work though blocking IN, and potentially PIC, nuclear import. The work presented here represents a platform for further development of these specific inhibitors of HIV replication with therapeutic and prophylactic potential.

Intracellular immunization against HIV infection with an intracellular antibody that mimics HIV integrase binding to the cellular LEDGF protein

Preventing the protein-protein interaction of the cellular chromatin binding protein Lens Epithelium-Derived Growth Factor (LEDGF) and human immunodeficiency virus (HIV) integrase is an important possible strategy for anti-viral treatment for AIDS. We have used Intracellular Antibody Capture technology to isolate a single VH antibody domain that binds to LEDGF. The crystal structure of the LEDGF-VH complex reveals that the single domain antibody mimics the effect of binding of HIV integrase to LEDGF which is crucial for HIV propagation. CD4-expressing T cell lines were constructed to constitutively express the LEDGF-binding VH and these cells showed interference with HIV viral replication, assayed by virus capsid protein p24 production. Therefore, pre-conditioning cells to express antibody fragments confers effective intracellular immunization for preventing chronic viral replication and can be a way to prevent HIV spread in infected patients. This raises the prospect that intracellular immunization strategies that focus on cellular components of viral integrase protein interactions can be used to combat the problems associated with latent HIV virus re-emergence in patients. New genome editing development, such as using CRISPR/cas9, offer the prospect intracellularly immunized T cells in HIV+ patients.

Implications of Measurement Assay Type in Design of HIV Experiments.

Time series measurements of circular viral episome (2-LTR) concentrations enable indirect quantification of persistent low-level Human Immunodeficiency Virus (HIV) replication in patients on Integrase-Inhibitor intensified Combined Antiretroviral Therapy (cART). In order to determine the magnitude of these low level infection events, blood has to be drawn from a patients at a frequency and volume that is strictly regulated by the Institutional Review Board (IRB). Once the blood is drawn, the 2-LTR concentration is determined by quantifying the amount of HIV DNA present in the sample via a PCR (Polymerase Chain Reaction) assay. Real time quantitative Polymerase Chain Reaction (qPCR) is a widely used method of performing PCR; however, a newer droplet digital Polymerase Chain Reaction (ddPCR) method has been shown to provide more accurate quantification of DNA. Using a validated model of HIV viral replication, this paper demonstrates the importance of considering DNA quantification assay type when optimizing experiment design conditions. Experiments are optimized using a Genetic Algorithm (GA) to locate a family of suboptimal sample schedules which yield the highest fitness. Fitness is defined as the expected information gained in the experiment, measured by the Kullback-Leibler Divergence (KLD) between the prior and posterior distributions of the model parameters. We compare the information content of the optimized schedules to uniform schedules as well as two clinical schedules implemented by researchers at UCSF and the University of Melbourne. This work shows that there is a significantly greater gain information in experiments using a ddPCR assay vs. a qPCR assay and that certain experiment design considerations should be taken when using either assay.

The Causes of HIV-Associated Cardiomyopathy: A Tale of Two Worlds.

Antiretroviral therapy (ART) has transformed the clinical profile of human immunodeficiency virus (HIV) from an acute infection with a high mortality into a treatable, chronic disease. As a result, the clinical sequelae of HIV infection are changing as patients live longer. HIV-associated cardiomyopathy (HIVAC) is a stage IV, HIV-defining illness and remains a significant cause of morbidity and mortality among HIV-infected individuals despite ART. Causes and clinical manifestations of HIVAC depend on the degree of host immunosuppression. Myocarditis from direct HIV toxicity, opportunistic infections, and nutritional deficiencies are implicated in causing HIVAC when HIV viral replication is unchecked, whereas cardiac autoimmunity, chronic inflammation, and ART cardiotoxicity contribute to HIVAC in individuals with suppressed viral loads. The initiation of ART has dramatically changed the clinical manifestation of HIVAC in high income countries from one of severe, left ventricular systolic dysfunction to a pattern of subclinical cardiac dysfunction characterized by abnormal diastolic function and strain. In low and middle income countries, however, HIVAC is the most common HIV-associated cardiovascular disease. Clear diagnostic and treatment guidelines for HIVAC are currently lacking but should be prioritized given the global burden of HIVAC.

Liver Fibrosis in HIV Patients Receiving a Modern cART: Which Factors Play a Role?

Liver-related death in human immunodeficiency virus (HIV)-infected individuals is about 10 times higher compared with the general population, and the prevalence of significant liver fibrosis in those with HIV approaches 15%. The present study aimed to assess risk factors for development of hepatic fibrosis in HIV patients receiving a modern combination anti-retroviral therapy (cART). This cross-sectional prospective study included 432 HIV patients, of which 68 (16%) patients were anti-hepatitis C virus (HCV) positive and 23 (5%) were HBsAg positive. Health trajectory including clinical characteristics and liver fibrosis stage assessed by transient elastography were collected at inclusion. Liver stiffness values >7.1 kPa were considered as significant fibrosis, while values >12.5 kPa were defined as severe fibrosis. Logistic regression and Cox regression uni- and multivariate analyses were performed to identify independent factors associated with liver fibrosis. Significant liver fibrosis was detected in 10% of HIV mono-infected, in 37% of HCV co-infected patients, and in 18% of hepatitis B virus co-infected patients. The presence of diabetes mellitus (odds ratio [OR] = 4.6) and FIB4 score (OR = 2.4) were independently associated with presence of significant fibrosis in the whole cohort. Similarly, diabetes mellitus (OR = 5.4), adiposity (OR = 4.6), and the FIB4 score (OR = 3.3) were independently associated with significant fibrosis in HIV mono-infected patients. Importantly, cumulative cART duration protected, whereas persistent HIV viral replication promoted the development of significant liver fibrosis along the duration of HIV infection. Our findings strongly indicate that besides known risk factors like metabolic disorders, HIV may also have a direct effect on fibrogenesis. Successful cART leading to complete suppression of HIV replication might protect from development of liver fibrosis.

Lopinavir/ritonavir en pacientes infectados por el virus de la inmunodeficiencia humana en situaciones especiales

Ritonavir-boosted lopinavir (LPV/r) is a protease inhibitor used for the treatment of human immunodeficiency virus (HIV) infection in both normal patients and in certain situations. In patients with renal failure, LPV/r does not require dosage adjustment because it is metabolized in the liver. Cohort studies have shown that the incidence of varying degrees of renal disease and/or crystalluria related to combination antiretroviral therapy with tenofovir and some protease inhibitors (PI) does not appear with LPV/r or that the incidence is much lower with this combination. Neurocognitive impairments are described in a high proportion of patients with HIV infection and viral replication or related inflammatory activity in the subarachnoid space. In these patients, LPV/r is one of the therapeutic options. A score has been published that rates antiretroviral drugs according to the concentration attained in the cerebrospinal fluid (CSF). LPV/r levels reached in CSF exceed the IC50 of wild-type HIV and has a valuable score (score 3) of the drugs currently used. The most important comorbid condition is chronic hepatitis, due to its frequency and because the biotransformation of LPV/r occurs in the liver. In these circumstances, it is important to evaluate the influence of liver failure on blood drug levels and how these values may cause liver toxicity. LPV/r dose modification has not been established in the presence of liver failure. LPV/r-induced liver toxicity has only been reported with a certain frequency when liver enzymes were elevated at baseline or in patients with chronic hepatitis C, although most cases of liver toxicity were mild.

Survival rate of AIDS disease and mortality in HIV-infected patients in Hamadan, Iran: a registry-based retrospective cohort study (1997–2011)

There remains a need to better understand the prognostic factors affecting the long-term survival in patients with human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome (AIDS), particularly in developing countries. We extracted data from 585 patients' medical records available at the triangular clinics for behavioural diseases. The outcomes of interest were the survival rates of progression to AIDS and death in HIV-positive subjects. The effect of several prognostic factors on survival time was investigated. One-year, five-year and 10-year survival rates from time of HIV diagnosis to AIDS were 89%, 69% and 30%, respectively. One-year and five-year survival rates from AIDS to death were 76% and 46%, respectively. One-year, five-year and 10-year survival rate from HIV diagnosis to death were 87%, 67% and 40%, respectively. Hazard ratio of progression to AIDS in HIV-positive subjects who were co-infected with tuberculosis was 4.50 (p < 0.001). Hazard ratio of death from AIDS-related causes was 4.77 in patients who did not receive highly active antiretroviral therapy compared to those who did (p < 0.001). Co-infection with tuberculosis was one of the most important prognostic factors of progression to AIDS and antiretroviral treatment was found to be an effective measure in suppressing HIV viral replication and improving the survival of patients living with HIV.

Influence of GB virus C on IFN-γ and IL-2 production and CD38 expression in T lymphocytes from chronically HIV-infected and HIV-HCV-co-infected patients

This study was designed to assess the effect of GB virus (GBV)-C on the immune response to human immunodeficiency virus (HIV) in chronically HIV-infected and HIV- hepatitis C virus (HCV)-co-infected patients undergoing antiretroviral therapy. A cohort of 159 HIV-seropositive patients, of whom 52 were HCV-co-infected, was included. Epidemiological data were collected and virological and immunological markers, including the production of interferon gamma (IFN-γ) and interleukin (IL)-2 by CD4, CD8 and Tγδ cells and the expression of the activation marker, CD38, were assessed. A total of 65 patients (40.8%) presented markers of GBV-C infection. The presence of GBV-C did not influence HIV and HCV replication or TCD4 and TCD8 cell counts. Immune responses, defined by IFN-γ and IL-2 production and CD38 expression did not differ among the groups. Our results suggest that neither GBV-C viremia nor the presence of E2 antibodies influence HIV and HCV viral replication or CD4 T cell counts in chronically infected patients. Furthermore, GBV-C did not influence cytokine production or CD38-driven immune activation among these patients. Although our results do not exclude a protective effect of GBV-C in early HIV disease, they demonstrate that this effect may not be present in chronically infected patients, who represent the majority of patients in outpatient clinics.

Selective Serotonin Reuptake Inhibitor Suppression of HIV Infectivity and Replication

To test the hypothesis that the selective serotonin reuptake inhibitor (SSRI) citalopram would down-regulate human immunodeficiency virus (HIV) infectivity and that the greatest effects would be seen in people with depression. Depression is a risk factor for morbidity and mortality in HIV/acquired immune deficiency syndrome. Serotonin (5-HT) neurotransmission has been implicated in the pathobiology of depression, and pharmacologic therapies for depression target this system. The 5-HT transporter and 5-HT receptors are widely distributed throughout the central nervous and immune systems. Depression has been associated with suppression of natural killer cells and CD8(+) lymphocytes, key regulators of HIV infection. Ex vivo models for acute and chronic HIV infection were used to study the effects of citalopram on HIV viral infection and replication in 48 depressed and nondepressed women. For both the acute and chronic infection models, HIV reverse transcriptase activity was measured in the citalopram treatment condition and the control condition. The SSRI significantly down-regulated the reverse transcriptase response in both the acute and chronic infection models. Specifically, citalopram significantly decreased the acute HIV infectivity of macrophages. Citalopram also significantly decreased HIV viral replication in the latently infected T-cell line and in the latently infected macrophage cell line. There was no difference in down-regulation by depression status. These studies suggest that an SSRI enhances natural killer/CD8 noncytolytic HIV suppression in HIV/acquired immune deficiency syndrome and decreases HIV viral infectivity of macrophages, ex vivo, suggesting the need for in vivo studies to determine a potential role for agents targeting serotonin in the host defense against HIV.

Sexually acquired HIV infections in the United States due to acute-phase HIV transmission: an update

Identification of acute human immunodeficiency virus (HIV) infection, the stage of disease during the first few months of infection in which HIV viral replication and shedding peak before HIV antibodies are detectable [1], is of public health importance because acutely infected persons are likely to be unaware of their status and more infectious and may continue to engage in high-risk behavior that furthers HIV transmission. Pinkerton [2] used a simple mathematical model to estimate the number and proportion of sexually acquired HIV infections in the United States that are due to acute-phase transmission and found that an estimated 2760 persons acquired HIV as a consequence of risky sexual activities with an acutely infected sex partner. This accounted for 8.6% of the approximately 32 000 (then estimated) sexually acquired HIV infections each year. Since Pinkerton's estimates were published, the Centers for Disease Control and Prevention (CDC) reported annual HIV incidence estimates in the United States that are about 40% higher than previously estimated, increasing from 40 000 to 56 300 [3]. CDC also updated estimates for prevalence [4] and the proportion of undiagnosed HIV infections [5]. These changes in HIV surveillance data create a need for updated transmission estimates. We used Pinkerton's [2] framework and updated the model to reflect recently published HIV surveillance data. We used the latest prevalence estimates for persons living with HIV/AIDS (PLWH) [4], undiagnosed PLWH [5], and HIV incidence estimates [3]. We assumed that other parameters remained the same (Table 1).Table 1: Comparison with Pinkerton's estimates.The proportion of incident infections due to sexual transmission from a HIV-positive partner in an acute-HIV infection phase (Ia) remains (from [2]) where μ12 is the transmission rate ratio for acutely infected vs. nonacutely infected serostatus-unaware PLWH. μ23 is the transmission rate ratio for the nonacutely infected serostatus-unaware vs. serostatus-aware PLWH. N1 is the number of acutely infected PLWH available on a particular day. N2 is the number of nonacutely infected serostatus-unaware PLWH. N3 is the number of nonacutely infected serostatus-aware PLWH. In addition to the 45 500 new infections transmitted sexually [3], we assumed that some of the incident infections reported under men who have sex with men (MSM)/injection drug users (IDU) transmission category were caused sexually. The sexual and IDU transmissions in the MSM/IDU group were assumed to be in the same proportion as the ratio of incidence of MSM-only and IDU-only transmission groups (28 700: 6600 = 4.34: 1). Based on this ratio, about 1700 of the 2100 new MSM/IDU infections each year can be considered as sexually transmitted. We estimate that about 5371 persons each year acquired HIV as a consequence of risky sexual activities with an acutely infected sex partner in the United States. This accounts for about 11.4% of the total annual incident sexual infections compared with 8.6% as estimated by Pinkerton. PLWH unaware of their infections are estimated to be the sources for about 53.2% of the new infections. The overall transmission rate per PLWH is estimated at 0.012% per day (0.009% per day estimated by Pinkerton). The transmission rate per PLWH in the acute phase is also higher at 0.195% per day (0.141% per day estimated by Pinkerton). Applying the latest incidence data and assigning a proportion of the MSM/IDU transmission category to the number of incident cases due to sexual transmission resulted in an increase in the proportion of sexual transmissions due to acute phase transmission in the United States over what Pinkerton previously estimated. As the increase in incidence (40%) was larger than that in prevalence (10%), daily and annual transmission rates for all PLWH categories, including acutely infected PLWH, increased as they were computed as a ratio of incident infections. Our findings are consistent with Pinkerton's in that the proportion of sexually acquired infections in the United States due to acute-phase transmission is much smaller than has been suggested [9,10]. Our updated analysis is also useful, as it provides updated annual and daily transmission rates for acutely and nonacutely infected PLWH. Additional research on the risk behavior of persons with acute HIV infection in the United States, particularly their risk behavior after notification of their HIV status, is needed to further refine these estimates. Our analysis is subject to the same limitations as Pinkerton's analysis, particularly uncertainty in key parameters used to derive the acute phase transmission rate ratio [6–8]; however, our analysis does use updated, and likely more reliable, incidence data than were used in the Pinkerton analysis. In addition, our analysis does not include sensitivity analysis. Acknowledgements V.S.P., A.B.H., P.G.F., and S.L.S. contributed equally to the conception and design of the paper. V.S.P. conducted the analysis and wrote the first draft. A.B., P.G.F., and S.L.S. helped revise the draft. All the authors were involved in the final approval of the manuscript.

Increased Interleukin-17 Production Both in Helper T Cell Subset Th17 And CD4-Negative T Cells in Human Immunodeficiency Virus Infection

Interleukin (IL)-17 is produced mainly by activated CD4(+) T cells, currently known as Th17. Human immunodeficiency virus (HIV) pathogenesis leads to CD4(+) T cell depletion. This is the first report of IL-17 in HIV infection. We assessed IL-17 expression in the CD4(+) T cells (Th17) of 40 asymptomatic HIV-infected treatment-naive patients compared with 40 HIV-seronegative volunteers. Peripheral blood mononuclear cells (PBMCs), with/without phorbol myristate acetate (PMA)/ionomycin stimulation, were stained with CD3, CD4, IL-17, and interferon (IFN)-gamma antibodies and analyzed by four-color flow cytometry. Both groups had comparable baseline data, except for age (mean+/-SD): 36 +/- 9 versus 30 +/- 9 yr (p= 0.001), CD4(+) T cell counts (median): 218 versus 623 cells/microL (p < 0.0001), CD8(+) T cell counts (median): 875.5 versus 382.5 cells/microL ((p) < 0.0001), and CD4(+)/CD8(+) cell ratios (median): 0.225 versus 1.45 (p< 0.0001). Without stimulation, the percentages of IL-17(+) CD3(+) CD4() and IL-17(+) CD3(+) CD4() cells among HIV-seropositive and -seronegative volunteers (median) were as follows: 0.68 versus 0.12% (p< 0.0001) and 0.92 versus 0.09% (p< 0.0001), respectively. With PMA/ionomycin stimulation, the percent IL-17 expression in CD4(+) cells (median) was 1.45 versus 0.65 (p< 0.0001) and in CD4() T cells it was 1.0 versus 0.12 (p< 0.0001). In conclusion, HIV infection is associated with a significant increase in IL-17 production in both CD4(+) and CD4() T cells in peripheral blood. IL-17 expression was further inducible by PMA/ionomycin stimulation in vitro only in CD4(+) T cells. The roles of IL-17 and Th17 in HIV viral replication and immunopathogenesis are under further investigation.

Effect of influenza virus vaccine on the expression of human immunodeficiency virus co-receptor CCR5

Administration of influenza vaccine to human immunodeficiency virus (HIV)-infected children can lead to increased viral load. CCR5 and CXCR4 are known to play an important role in HIV cell entry and viral replication. To determine the effects of influenza vaccine on chemokine receptors and on viral load in HIV-infected children. Eight HIV-infected children receiving stable therapy and 11 healthy adults were enrolled. Chemokine expression and immune activation were determined before and 48 hours after influenza vaccination. CCR5 and beta-chemokine gene expression were analyzed using real-time polymerase chain reaction. Viral load was measured at baseline, 48 hours, and 6 to 12 weeks. Forty-eight hours after influenza vaccination, mean CCR5 expression was significantly decreased on the CD3 (21.1% vs 11.3% in HIV-infected children; P = .02; and 18.3% vs 10.7% in controls; P = .008) and CD4 (13.0% vs 3.6% in the HIV group; P = .04; and 13.6% vs 6.5% in controls; P = .02) lymphocytes. This was observed in conjunction with an increase in HLA-DR expression on T lymphocytes in HIV-infected children (P = .046). No significant changes were observed in HIV viral load, CD3 and CD8 lymphocyte counts, expression of interleukin 2 receptor and CXCR4, or gene expression of CCR5 and beta-chemokines 48 hours after vaccination. Influenza virus vaccine markedly decreased chemokine receptor CCR5 expression on CD4 T lymphocytes. However, this immunomodulatory effect does not seem to affect overall viral replication in HIV-infected children who received highly active antiretroviral therapy.

Host cell gene expression during human immunodeficiency virus type 1 latency and reactivation and effects of targeting genes that are differentially expressed in viral latency.

The existence of reservoirs of cells latently infected with human immunodeficiency virus (HIV) is a major obstacle to the elimination of HIV infection. We studied the changes in cellular gene expression that accompany the reactivation and completion of the lytic viral cycle in cell lines chronically infected with HIV-1. We found that several genes exhibited altered expression in the chronically infected cells compared to the uninfected parental cells prior to induction into lytic replication. A number of gene classes showed increased expression in the chronically infected cells, notably including genes encoding proteasomes, histone deacetylases, and many transcription factors. Following induction of the lytic replication cycle, we observed ordered, time-dependent changes in the cellular gene expression pattern. Approximately 1,740 genes, many of which fall into 385 known pathways, were differentially expressed (P < 0.001), indicating that completion of the HIV replication cycle is associated with distinct, temporally ordered changes in host cell gene expression. Maximum changes were observed in the early and intermediate phases of the lytic replication cycle. Since the changes in gene expression in chronically infected cells suggested that cells latently infected with HIV have a different gene expression profile than corresponding uninfected cells, we studied the expression profiles of three different chronically infected cell lines to determine whether they showed similar changes in common cellular genes and pathways. Thirty-two genes showed significant differential expression in all cell lines studied compared to their uninfected parental cell lines. Notable among them were cdc42 and lyn, which were downregulated and are required for HIV Nef binding and viral replication. Other genes previously unrelated to HIV latency or pathogenesis were also differentially expressed. To determine the effects of targeting products of the genes that were differentially expressed in latently infected cells, we treated the latently infected cells with a proteasome inhibitor, clastolactacystin-beta-lactone (CLBL), and an Egr1 activator, resveratrol. We found that treatment with CLBL and resveratrol stimulated lytic viral replication, suggesting that treatment of cells with agents that target cellular genes differentially expressed in latently infected cells can stimulate lytic replication. These findings may offer new insights into the interaction of the latently infected host cell and HIV and suggest therapeutic approaches for inhibiting HIV infection and for manipulating cells latently infected with HIV so as to trigger lytic replication.

Nitric Oxide Inhibits HIV Tat-Induced NF-κB Activation

To evaluate the roles of nitric oxide (NO) on human immunodeficiency virus (HIV) Tat-induced transactivation of HIV long terminal repeat (HIV-LTR), we examined the effect of NO in the regulation of nuclear factor (NF)-kappaB, a key transcription factor involved in HIV gene expression and viral replication. In the present study, we demonstrate that HIV Tat activates NF-kappaB and that this activation can be attenuated by endogenous or exogenous NO. Inhibition of endogenous NO production with the NO synthase (NOS) inhibitor L-NMMA causes a significant increase in Tat-induced NF-kappaB activity. In addition, NO attenuates signal-initiated degradation of IkappaBalpha, an intracellular inhibitor of NF-kappaB, and blocks the DNA binding activity of the NF-kappaB p50/p50 homodimer and p50/p65 heterodimer. To determine how NO is induced by HIV Tat, reverse transcription polymerase chain reaction was used to demonstrate the induction of NOS-2 and NOS-3 mRNA by Tat. Although a putative NF-kappaB binding site was identified in the -74 GGAGAGCCCCC -64 region of the NOS-3 gene promoter, gel mobility shift assays and site-directed mutation analyses suggest that the putative NF-kappaB site is not of primary importance. Rather, several Sp-1 sites adjoining the putative NF-kappaB binding site in the promoter region of NOS-3 gene are required for the induction of NOS-3 gene expression by Tat.

Serum Malondialdehyde in HIV Seropositive Children

Human immunodeficiency virus (HIV) infection is associated with oxidative stress as it has been demonstrated in adult seropositive individuals. We show in this study that serum malondialdehyde (MDA) concentration of HIV infected children was significantly higher than in control children. Moreover, a statistically significant decreased serum antioxidant status was detected in HIV infected children when compared with controls. No correlation was found in HIV infected children between their clinical or immunological categories, CD4+ lymphocyte count or CD4+/CD8+ ratio, and MDA concentration or serum antioxidant status. Newborn from HIV seropositive mothers had also a higher MDA concentration in cord blood serum than their corresponding controls from HIV seronegative mothers, whereas no difference could be established in the serum antioxidant status between both groups. No apparent correlation could be established between birth weight, gestational age or APGAR test values, and MDA in any of these groups. The results presented, (i.e., the increase of MDA concentration in HIV seropositive infants and children, and the decrease in serum total antioxidants in HIV seropositive children) confirm the involvement of oxidative stress in the pathophysiology of this infection also in childhood. Because of the importance of oxidative stress and antioxidants for HIV viral replication, the adequacy of an adjuvant therapy with antioxidants should be considered; an adequate candidate for it could be N-acetyl-cysteine.

Serum malondialdehyde in HIV-seropositive children negatively correlates with CD4+ lymphocytes count.

Human immunodeficiency virus (HIV) infection is associated with oxidative stress as it has been demonstrated in adult-seropositive individuals. We show in this study that serum malondialdehyde (MDA) concentration of HIV-infected children was significantly higher than in control children. A negative correlation (r = -0.515) was found in HIV-infected children between their CD4+ lymphocyte count, and MDA concentration but not with serum antioxidant status. The increase of MDA concentration in HIV-seropositive children confirms the involvement of oxidative stress in the pathophysiology of this infection also in childhood. Because of the importance of oxidative stress and antioxidants for HIV viral replication, the adequacy of an adjuvant therapy with antioxidants should be considered; an adequate candidate for it could be N-acetylcysteine.

Specific ablation of human immunodeficiency virus Tat-expressing cells by conditionally toxic retroviruses.

The identification of human immunodeficiency virus (HIV) as the etiologic agent of AIDS has led to the proposal of novel intervention strategies to block HIV infection and viral replication or eliminate HIV-infected cells. We have produced recombinant retroviruses for a molecular ablation system, whereby a toxin gene can be delivered to hematopoietic cells for the specific elimination of HIV Tat-expressing cells. For this cell-specific ablation, we have coupled the conditional toxin herpes simplex virus type 1 thymidine kinase (tk) gene to the HIV-2 promoter and Tat responsive region (TAR) in order that transcriptional activity be under the absolute control of HIV and simian immunodeficiency virus Tat trans-activator proteins. Since the HIV-2 promoter has a considerable level of basal expression in the absence of Tat, we constructed a number of modifications in the HIV-2 promoter to minimize the risk of cytotoxicity to cells not containing HIV Tat. We demonstrate that certain promoter modifications reduce basal transcription while maintaining high trans-activated levels of expression when transfected or transduced by retroviral vectors into several different cell lines. In mouse and human cells infected with HIV-2 tk retroviruses, we show that Tat-induced expression from the HIV-2 promoter results in differential ablation and a massive reduction in Tat-positive cells after ganciclovir treatment. Thus, the retroviruses produced in these studies may be applicable to HIV ablative therapy.