Federico Bolcic

HIV-1 Induces Telomerase Activity in Monocyte-Derived Macrophages, Possibly Safeguarding One of Its Reservoirs

ABSTRACT Monocyte-derived macrophages (MDM) are widely distributed in all tissues and organs, including the central nervous system, where they represent the main part of HIV-infected cells. In contrast to activated CD4+ T lymphocytes, MDM are resistant to cytopathic effects and survive HIV infection for a long period of time. The molecular mechanisms of how HIV is able to persist in macrophages are not fully elucidated yet. In this context, we have studied the effect of in vitro HIV-1 infection on telomerase activity (TA), telomere length, and DNA damage. Infection resulted in a significant induction of TA. This increase was directly proportional to the efficacy of HIV infection and was found in both nuclear and cytoplasmic extracts, while neither UV light-inactivated HIV nor exogenous addition of the viral protein Tat or gp120 affected TA. Furthermore, TA was not modified during monocyte-macrophage differentiation, MDM activation, or infection with vaccinia virus. HIV infection did not affect telomere length. However, HIV-infected MDM showed less DNA damage after oxidative stress than noninfected MDM, and this resistance was also increased by overexpressing telomerase alone. Taken together, our results suggest that HIV induces TA in MDM and that this induction might contribute to cellular protection against oxidative stress, which could be considered a viral strategy to make macrophages better suited as longer-lived, more resistant viral reservoirs. In the light of the clinical development of telomerase inhibitors as anticancer therapeutics, inhibition of TA in HIV-infected macrophages might also represent a novel therapeutic target against viral reservoirs.

Hepatitis B virus, hepatitis C virus and HIV coinfection among people living with HIV/AIDS in Buenos Aires, Argentina.

The HIV epidemic in Argentina has changed since the first case was reported in 1982. Since the beginning of the 1990s, a decrease in the number parenterally acquired infections has been observed, with a marked increase in transmission through unprotected sexual contact (heterosexual and homosexual), and in the number of women living with HIV/AIDS [1]. Few prevalence studies have addressed the hepatitis B and C virus coinfection in Argentina. We performed this study in a large single clinic in Buenos Aires, taking care of more than 3,000 HIV patients. During a seven-month period (9/2004 to 3/2005), all HIV-positive patients ≥ 18 years old, who were followed up at our unit and who had their scheduled controls for HIV viral load (VL) at the Argentinean National Reference Centre for AIDS (CNRS), were invited to participate in the study. The study was approved by the Fernandez Hospital Ethics Committee. Patients gave their informed consent to be included in the study. Six hundred subjects were asked to enter the study, and 593 accepted. Studied population: 65.6% males, 64% young adults between 20 and 40 years old. The main route of HIV infection was through sexual contact (70%). Of the 593 samples, 52% (n=308) showed positive results for serological markers (HBcAb/HBsAg/anti-HCV) for hepatitis B or C coinfection. Coinfection rates and subjects characteristics are described in Table 1. Table 1 Demographics, rates of HCV/HBV coinfection, main routes of infection, median levels of CD4 cell count, HIV viral load, HAART, frequency of ALT level among HIV-positive patients studied HBV genotype A was identified in 85% of the samples with detectable HBV DNA, instead of genotype F, the most prevalent in our country among blood donors [2]. Among the 22 HBsAg-positive samples, four showed mutations in the rt domain of the pol gene. These samples belonged to patients who had a prolonged history of exposure to lamivudine (median: 25 months) and none of them had received tenofovir. This data reinforces the importance of adequate management of drugs with HBV/HIV dual activity when selecting antiretroviral therapies in coinfected patients, as stated in the last update of the European and North American guidelines for the use of antiretroviral agents in HIV-1-infected adults and adolescents [3,4]. The main isolated HCV genotype was 1 (65%), followed by genotype 3 (16.5%). Our study shows a change in the prevalence of HCV and HBV coinfection comparing with a previous report of the same geographical area [5], among people living with HIV/AIDS in Buenos Aires, the city with the highest prevalence of HIV in Argentina. A reduction in prevalence rates of dual HIV/HCV (from 58.5% in 1999 to 21%, p 0.000) and HIV/HBV coinfection (from 14.5% in 1999 to 3.7%, p 0.000) was observed. This could be related to the decreasing number of injecting drug users in our country because of the introduction of non-injecting recreational drugs and the increasing transmission through unprotected sex [1]. Despite the decrease in the rates of HCV/HIV and HBV/HIV coinfections the prevalence of those coinfections continues to be high and it could lead to the increase in the morbidity and mortality associated with liver disease, especially in the context of expanded antirretroviral therapy in Argentina. The epidemiological data presented in this study provides information for the development of prevention campaigns for hepatitis C through harm reduction policies and for hepatitis B vaccination programs among people living with HIV/AIDS.

HCV RNA decline in the first 24 h exhibits high negative predictive value of sustained virologic response in HIV/HCV genotype 1 co-infected patients treated with peginterferon and ribavirin

BACKGROUND Treatment with Peg-interferon and ribavirin (PEG-IFN/RBV) for HIV patients co-infected with hepatitis C virus (HCV) genotype 1 has suboptimal rates of response. Viral kinetics has emerged as one of the best prognostic factors of treatment outcome. METHODS Twenty HIV/HCV genotype 1 co-infected patients in treatment with PEG-IFN/RBV, had blood drawn at baseline, 24 h, 4, 12, 24, 48, and 72 weeks. HCV-RNA levels were evaluated at each time point. ROC curves were used to evaluate the log10 HCV-RNA decay at 24 h that exhibits the best predictive value of achieving response. Genomic characterization of HCV NS5A at both interferon sensitivity-determining region (ISDR) and protein-kinase binding (PKRBD) domains were performed in order to evaluate its heterogeneity and association with 24 h HCV-RNA decay and SVR. RESULTS Non-responder patients exhibited a mean of 0.7 log10 (SD 0.74 log10) HCV-RNA decay at 24 h, whereas responder-patients presented 1.6 log10 (SD 0.28 log10), p = 0.04. A reduction in HCV viral load from baseline to 24 h of < 1.4 had a negative predictive value for achieving SVR of 100% and a positive predictive value of 50%. HCV genotype 1 isolates from patients with a decrease of HCV-RNA at 24 h > 1.4 log10, exhibited 3.1(SD 1.5) amino acids substitutions in ISDR and 4.8(SD 2.3) in PKRBD regions and 1.6(SD 0.7) and 2.4(SD 1.3), respectively, in those patients presenting lower reduction in HCV-RNA. CONCLUSIONS HIV/HCV genotype 1 co-infected patients with a decrease in HCV-VL at 24 h > 1.4 log10 are more likely to achieve SVR when treated with PEG-IFN/RBV than those with lower levels of HCV-RNA decay. Along with other host-related and viral-related prognostic factors in HIV/HCV co-infected patients, this very early time point of evaluation could be of relevance in the management of HCV-specific treatment.

Telomerase activity in peripheral blood mononuclear cells from HIV and HIV–HCV coinfected patients

Replicative senescence of peripheral blood mononuclear cells (PBMC) plays an important role in the pathophysiology of chronic viral infections. Although there are controversial reports concerning telomerase activity in HIV monoinfected subjects, no data on HIV-HCV coinfected individuals is available. In this cross-sectional study telomerase activity was quantified in non-stimulated and mitogen-stimulated PBMC lysates from HIV-1 monoinfected and HIV-HCV coinfected individuals using real-time PCR. Up-regulation of telomerase activity after mitogen stimulation was impaired in PBMC of HIV monoinfected and HIV-HCV coinfected patients. The lack of an appropriate induction of this enzymatic activity after stimulus could partly account for immunosuppressive conditions observed in such patients.

Molecular characterization of hepatitis C virus genotype 4 sequences in HIV‐coinfected patients from Argentina

The prevalence of hepatitis C virus genotype 4 (HCV‐4) is increasing in different parts of the World but in Latin America the data are still scarce. We aimed to characterize HCV‐4 isolates from 383 HIV‐coinfected patients in Argentina. Sequence analyses were based on the non‐structural 5B region of HCV. Results from 18 patients indicated a genetic heterogeneity that involved three genotype 4 subtypes. Sequences were ascribed to subtype 4d (67%), 4a (22%), and 4m (11%). In spite of different sources of transmission were defined among patients, no statistical association was found with the genotype 4 subtype. The scenario is also compatible with multiple importation of the epidemic and there is no evidence for transmission‐specific clusters or network‐like transmission of HCV‐4. This HCV‐4 does not represent a recent introduction in Argentina, it circulates in all transmission groups and its presence is increasing among HIV‐infected patients. J. Med. Virol. 83:935–940, 2011.

No reduction of HCV viral load in HIV patients co-infected with HCV genotype 1 during a 30 days course of nitazoxanide monotherapy.

There are two new drugs approved and several in development for treatment of chronic HCV; among them nitazoxanide (NTZ). Twelve HIV/HCV genotype 1 co-infected patients were enrolled prospectively to receive a 30 days course of oral NTZ 500 mg bid. This therapy was well tolerated in this group of HIV patients co-infected with HCV genotype 1. Nevertheless no changes in HCV viral load were observed during treatment in none of the patients evaluated. This data suggests that despite the promising results reported for HCV genotype 4 mono-infected patients, NTZ exhibit poor activity as monotherapy in HIV/HCV co-infected patients with genotype 1.

A clustering phenomenon among HCV-1a strains among patients coinfected with HIV from Buenos Aires, Argentina.

The human immunodeficiency virus (HIV) and hepatitis C virus (HCV) share the same transmission routes which lead to high coinfection rates. Among HIV‐infected individuals such rates reached 21% in Argentina, being HCV‐1a the most predominant subtype. In this work, 25 HCV subtype 1a (HCV‐1a) strains from Argentinean patients coinfected with HIV were studied based on E2 and NS5A sequences. Phylogenetic analyses indicated that 12 strains were highly related to each other, constituting a highly supported (posterior probability = 0.95) monophyletic group that we called “M.” The remaining HCV strains (group dispersed or “D”) were interspersed along the phylogenetic trees. When comparing both groups of HCV‐1a, 10 amino acid differences were located in functional domains of E2 and NS5A proteins that appeared to affect eventually the peptides binding to MHC‐I molecules thus favoring immune escape and contributing to the divergence of HCV genotypes. Bayesian coalescent analyses for HCV‐1a cluster M isolates indicated that the time to the most recent common ancestor (tMRCA) overlaps with the age estimated recently for the HIV‐BF epidemic in Argentina. Furthermore, the genomic characterization based on pol gene analysis from HIV viremic patients showed that most HIV isolates from patients coinfected with HCV‐1a cluster M were BF recombinants with identical recombination patterns. In conclusion, these results suggest the presence of an HCV‐1a monophyletic cluster with a potential HIV co‐transmission by phylogenetic analyses. J. Med. Virol. 84:570–581, 2012.

The Hepatitis C Virus 5′UTR Genomic Region Remains Highly Conserved Under HAART: A 4- to 8-Year Longitudinal Study from HCV/HIV Co-Infected Patients

It has been reported that hepatitis C virus (HCV) may be lymphotropic in the setting of human immunodeficiency virus type 1 (HIV-1) coinfection. In HIV-infected subjects, HCV may replicate in the same cells as HIV-1, which increases the opportunity for direct interactions between these pathogens. Without any antiviral-therapy pressure, both viruses could establish a competitive relation for this particular cellular scenario.1

Uncommon hepatitis B virus and/or hepatitis C virus occult infection in HIV-positive patients with abnormal level of hepatic enzyme.

Elevated liver enzyme levels, detected through liver function test (LFT), are markers of liveror biliary tract diseases. Alanine aminotransferase (ALT) is a more specific indicator of liverinflammation. These abnormal findings are very frequent in HIV infected patients and theirdiagnosis and management may be difficult because of intricacies of the pathogenic mechanisminvolved