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Bonaventura Clotet

Publications and source records attributed to Bonaventura Clotet.

At least 19 recordsLinked to original sources
PubMed2007

Variability in non-nucleoside reverse transcriptase and protease inhibitors concentrations among HIV-infected adults in routine clinical practice.

AIMS: The objective of this study was to assess interindividual variability in plasma trough concentrations of non-nucleoside reverse transcriptase inhibitors (NNRTI) and protease inhibitors (PI) among HIV-infected adults in an outpatient routine clinical practice setting. METHODS: The study included 117 patients who attended our clinic for routine outpatient blood tests and who were receiving antiretroviral therapy which included NNRTI or PI. Patients were not informed that drug concentrations were going to be assessed until blood sampling. The time of the last antiretroviral treatment intake and blood sampling were recorded. Drug concentrations were considered optimal if they were above the proposed minimum effective concentration. In addition, efavirenz, nevirapine and atazanavir concentrations were considered potentially toxic if they were higher than 4.0 mg l(-1), 6.0 mg l(-1), and 0.85 mg l(-1), respectively. RESULTS: Overall, interindividual variability in NNRTI and PI plasma concentrations was approximately 50%, and only 68.4% of the patients had drug concentrations within the proposed therapeutic range. Inappropriate adherence only explained 35% of subtherapeutic drug concentrations. CONCLUSION: Interindividual variability in trough concentrations of NNRTI and PI among HIV-infected adults is large in routine clinical practice, with drug concentrations being outside the therapeutic window in a significant proportion of patients. Therapeutic drug monitoring may be useful to guide antiretroviral therapy in clinical practice.

Adult↗
PubMed2007

Antiretroviral therapy interruption guided by CD4 cell counts and plasma HIV-1 RNA levels in chronically HIV-1-infected patients.

OBJECTIVE: We evaluated the safety of CD4 cell count and plasma HIV-1 RNA (pVL)-guided treatment interruptions (GTI) and determined predictors of duration of treatment interruption. METHODS: Chronically HIV-1-infected adults with sustained CD4 cell counts > 500 cells/microl and pVL < 50 copies/ml were randomly assigned to either continue with standard antiretroviral therapy (control group, n = 101) or to interrupt therapy aimed at maintaining CD4 cell counts > 350 cells/microl and pVL < 100,000 copies/ml (GTI group, n = 100). Both groups were followed for 2 years. RESULTS: There were no AIDS-defining illnesses or deaths in either group. Compared to controls, subjects interrupting therapy reduced treatment exposure by 67%, but suffered significantly more adverse events related to the intake of medication or to therapy interruption [relative hazard, 2.71; 95% confidence interval (CI), 1.64-4.49; P < 0.001), mainly due to an excess in mononucleosis-like symptoms. While GTI subjects demonstrated improvements in the psychosocial spheres of quality of life and pain reporting, GTI had no effect on the physical aspects of quality of life. Although both groups had a similar hazard for developing CD4 cell count < 200 cells/microl; at least 10% of subjects on GTI had CD4 cell counts < 350 cells/microl at every time point. Drug resistance mutations were detected in 36% of subjects but were selected de novo only in subjects interrupting non-nucleoside reverse transcriptase inhibitor therapy. Lower CD4 cell count nadir, higher set-point pVL and prior exposure to suboptimal regimens were all independent predictors of the need to reinitiate treatment. CONCLUSIONS: Overall, GTI were not as safe as continuing therapy. Despite achieving some improvements in quality of life, GTI did not reduce the overall rate of management-related adverse events.

Adult↗
PubMed2007

Lopinavir/ritonavir pharmacokinetics in HIV and hepatitis C virus co-infected patients without liver function impairment: influence of liver fibrosis.

BACKGROUND AND OBJECTIVE: To assess the influence of hepatitis C virus (HCV) co-infection and the extent of liver fibrosis on lopinavir/ritonavir pharmacokinetics in HIV-infected patients without liver function impairment. METHODS: Cross-sectional, comparative study enrolling HIV-infected adults receiving lopinavir/ritonavir (400 mg/100 mg twice daily). HIV/HCV co-infected patients were grouped as having advanced fibrosis (HCV+/FIB+, n=7) or not (HCV+/FIB-, n=8) based on the FIB-4 index. A full concentration-time profile was obtained for each patient, and blood samples were collected before (0), and 1, 2, 4, 6, 8, 10 and 12 hours after a lopinavir/ritonavir dose. Lopinavir and ritonavir concentrations in plasma were determined by high-performance liquid chromatography. Maximum and minimum plasma concentrations (Cmax and Cmin), area under the plasma concentration-time curve from 0 to 12 hours (AUC12), apparent oral clearance at steady state (CLss/F), and apparent volume of distribution after oral administration (Vd/F) were calculated for each individual using a non-compartmental approach. RESULTS: Twenty-six HCV- and 22 HCV+patients were enrolled. Lopinavir and ritonavir pharmacokinetics were comparable between HCV- and HCV+patients. However, the Vd/F of lopinavir was 125% higher in HCV+/FIB+patients than in HCV-patients (p=0.015) and 107% higher than in HCV+/FIB-(p=0.040) patients. The CLss/F of ritonavir was 40% lower in HCV+/FIB+patients than in HCV-patients (p=0.005) and 44% lower than in HCV+/FIB-patients (p=0.040). Thus, for ritonavir AUC12, Cmax and Cmin in HCV+/FIB+patients were 63%, 86% and 100% higher, respectively, when compared with those parameters in HCV-patients (p=0.005, p=0.012 and p=0.015, respectively), and 80%, 86% and 100% higher, respectively, when compared with levels in HCV+/FIB- patients (p=0.040, p=0.040 and p=0.029, respectively). CONCLUSION: Lopinavir exposure is similar in HIV-infected patients with or without HCV co-infection and without liver function impairment. However, ritonavir exposure may be higher in this setting, particularly in individuals with advanced liver fibrosis.

Area Under Curve↗
PubMed2006

Fitness landscape of human immunodeficiency virus type 1 protease quasispecies.

Here we show, at a high resolution (1%), the human immunodeficiency virus type 1 (HIV-1) protease gene quasispecies landscape from three infected naïve individuals. A huge range of genetic configurations was found (67%, 71%, and 80% of the nucleotide clones from the three individuals, respectively, were different), and these configurations created a dense net that linked different parts of the viral population. Similarly, a vast diversity of different protease activities was also found. Importantly, 65% of the analyzed enzymes had detectable protease activity, and 11% of the minority individual variants showed similar or better fitness than the master (most abundant) enzyme, suggesting that the viral complexity in this genomic region does not exclusively depend on the enzyme's catalytic efficiency. Several high-fitness minority variants had only one substitution compared to the master sequence, supporting the possibility that the rugged HIV-1 protease quasispecies fitness landscape may be formed by a continuous network that can be traversed by single mutational steps without passing through defective or less-adapted proteins.

Amino Acid Sequence↗
PubMed2006

HIV-1 protease catalytic efficiency effects caused by random single amino acid substitutions.

Protein evolution has occurred by successive fixation of individual mutations. The probability of fixation depends on the fitness of the mutation, and the arising variant can be deleterious, neutral, or beneficial. Despite its relevance, only few studies have estimated the distribution of fitness effects caused by random single mutations on protein function. The human immunodeficiency virus type 1 (HIV-1) protease was chosen as a model protein to quantify protein's tolerability to random single mutations. After determining the enzymatic activity of 107 single random mutants, we found that 86% of single mutations were deleterious for the enzyme catalytic efficiency and 54% lethal. Only 2% of the mutations significantly increased the catalytic efficiency of the enzyme. These data demonstrate the vulnerability of HIV-1 protease to single random mutations. When a second random mutagenesis library was constructed from an HIV-1 protease carrying a highly deleterious single mutation (D30N), a higher proportion of mutations with neutral or beneficial effect were found, 26% and 9%, respectively. Importantly, antagonist epistasis was observed between deleterious mutations. In particular, the mutation N88D, lethal for the wild-type protease, restored the wild-type catalytic efficiency when combined with the highly deleterious mutation D30N. The low tolerability to single random substitutions shown here for the wild-type HIV-1 protease contrasts with its in vivo ability to generate an adaptive variation. Thus, the antagonist epistasis between deleterious or lethal mutations may be responsible for increasing the protein mutational robustness and evolvability.

Amino Acid Substitution↗
PubMed2006

Characterization of a new circulating recombinant form comprising HIV-1 subtypes C and B in southern Brazil.

OBJECTIVE: To identify a new circulating recombinant form (CRF) of HIV-1 comprising two circulating subtypes in the southern region in Brazil, subtypes B and C. METHODS: A total of 152 HIV-positive patients followed at two hospitals in southern Brazil had their viral pol genes isolated by reverse transcriptase-polymerase chain reaction (PCR) from plasma. PCR products were sequenced and phylogenetically analysed using HIV-1 subtype reference sequences. Six full-length subtype C viruses from Brazil previously described as 'pure' strains were included in the analysis. Sequences suggestive of recombination were analysed by boot scanning and phylogenetic analyses of separate fragments. The common ancestry of recombinant strains was evaluated by similarity plot and informative site analyses. RESULTS: : HIV-1 subtypes commonly found in Brazil (B, C and F1) were observed. Sixty-two viruses were initially assigned as subtype C, but 15 viruses clustered in a separate internal clade. Pol from two full-length genomes of subtype C viruses grouped together with those samples. Boot scanning analysis showed that all 17 viruses had the same recombinant structure, with a 240 base pair fragment of subtype B in the middle of the reverse transcriptase pol region. Subtype B assignment of this fragment was confirmed by phylogenetic analyses using different methods of tree inference and cluster robustness tests. Mosaics were shown to have a common ancestry. CONCLUSION: As CRF_BC represents 11% of the HIV-1 viruses circulating in the southern region of the country, which borders several south American countries, the assessment of its spread is of pivotal importance to the HIV/AIDS epidemic in Brazil and Latin America.

Base Sequence↗
PubMed2006

Genetic evolution of gp41 reveals a highly exclusive relationship between codons 36, 38 and 43 in gp41 under long-term enfuvirtide-containing salvage regimen.

OBJECTIVE: To analyse the genetic changes in the gp41 protein in HIV-infected patients with detectable plasma viraemia receiving a long-term salvage enfuvirtide regimen. METHODS: We studied 13 heavily antiretroviral-experienced patients receiving a salvage regimen containing enfuvirtide. Substitutions in gp41 were analysed by population-based sequencing at baseline and longitudinally after the initiation of enfuvirtide treatment. To investigate sequence evolution we also analysed multiple gp41 clones from four selected patients. A Fisher's two-tailed test was used to assess the distribution of resistance-associated mutations in the clonal sequences. RESULTS: Mutations at positions 36 and 38 in gp41 (HR1) emerged rapidly (median emerging time 10 weeks), but disappeared at subsequent timepoints in most of the patients. Amino acid changes did not accumulate over time, with no patient having more than two mutations in HR1 after 6 months of treatment. The mutation N43D was not observed together with changes at positions 36 or 38 in any patient. Clonal analysis showed that the three main gp41 resistance mutations were highly mutually exclusive (P < 0.001), being present in individual clones and constituting independent populations. CONCLUSION: Substitutions at positions 36 and 38 are rapidly selected but disappear thereafter in HIV-1-infected patients failing an enfuvirtide-containing salvage therapy. We found a highly exclusive relationship between the three main enfuvirtide resistance-associated mutations (amino acids 36, 38 and 43), suggesting that the genetic evolution of HIV-1 gp41 protein is a dynamic and much more complex process than previously though.

Amino Acid Sequence↗
PubMed2006

Complete nucleotide sequence of genotype 4 hepatitis C viruses isolated from patients co-infected with human immunodeficiency virus type 1.

The hepatitis C virus (HCV) genotype 4 is spreading among southern European intravenous drug users, who are frequently co-infected with human immunodeficiency virus type 1 (HIV-1). Response to interferon (IFN) alpha-based therapies in HIV-1 positive patients co-infected with HCV genotype 4 is poor, similar to that obtained for HCV genotype 1 and much lower than for HCV genotypes 2 and 3. The lack of sequence data related to HCV of genotype 4 prompted us to sequence the complete genome of two genotype 4 variants isolated from two HIV-1 co-infected patients (24 and 25). Our aim was to investigate the evolutionary relationships of the former variants with other genotypes and/or genotype 4 subtypes. Sequence alignments and phylogenetic analysis from genomic regions 5'NC, core-E1 and NS5B revealed that the variants isolated from patients 24 and 25 (both subtyped 4c/4d by INNO-LIPA II HCV) belong to subtypes 4d and 4a, respectively. When looking at the complete genome sequence one of the variants showed a new genotype 4 subtype. Interestingly, sequence length differences in the interferon sensitivity determining region coding regions were observed when compared with sequences from other genotypes. Similarly, when the catalytic efficiency of the NS3/4 protease from patients 24 and 25 samples were determined, they displayed 70.6+/-7.7 and 23.5+/-3.4%, respectively, of the activity shown by genotype 1 NS3/4 proteases. Overall, pairwise comparison and phylogenetic analysis of nucleotide sequences of the complete genome or the different protein-encoding regions showed that genotype 4 sequences were more closely related to genotype 1 sequences. The description of new HCV genome variants may help our understanding of the HCV biology as well as the role of different genotypes in HCV treatment and therapy response.

Amino Acid Sequence↗
PubMed2006

Viral failure in HIV-infected patients with long-lasting viral suppression who discontinued enfuvirtide.

The aim of this pilot study was to assess whether enfuvirtide can be discontinued in patients on long-term viral suppression. Eight patients with multidrug-resistant virus were randomly assigned to stop and 10 subjects to continue enfuvirtide. At week 48, viral rebound occurred in five (62.5%) and in no patients, respectively, (P = 0.007). The CD4 cell decrease in failure patients was 5% (P = ns). These results suggest that enfuvirtide should be maintained until new active drugs became available.

ADP-ribosyl Cyclase 1↗
PubMed2006

Durable efficacy of tipranavir-ritonavir in combination with an optimised background regimen of antiretroviral drugs for treatment-experienced HIV-1-infected patients at 48 weeks in the Randomized Evaluation of Strategic Intervention in multi-drug reSistant patients with Tipranavir (RESIST) studies: an analysis of combined data from two randomised open-label trials.

BACKGROUND: Treatment options for HIV-1 infected individuals who have received extensive previous antiretroviral therapy are limited. We compared efficacy and safety of the novel non-peptidic protease inhibitor tipranavir co-administered with ritonavir plus an optimised background regimen with that of an investigator-selected ritonavir-boosted comparator protease inhibitor (CPI-ritonavir) in such patients. METHODS: We did a combined analysis of 48-week data from two ongoing, randomised, open-label, multinational, phase III, RESIST studies. HIV-1-infected adults with 3 months or longer previous triple antiretroviral class experience, two or more previous protease inhibitor regimens, HIV-1 RNA 1000 copies per mL or greater, and genotypically demonstrated primary resistance to protease inhibitor, were eligible. Primary endpoints were proportion of treatment responders (with reduction in viral load of 1 log(10) copies per mL or greater below baseline without treatment change) at 48 weeks and time to treatment failure through 48 weeks (intention-to-treat analysis). The RESIST studies are registered with ClinicalTrials.gov, numbers NCT00054717 (RESIST-1) and NCT00144170 (RESIST-2). FINDINGS: 3324 patients were screened; 746 received tipranavir-ritonavir and 737 CPI-ritonavir. 486 (65.1%) patients on tipranavir-ritonavir and 192 (26.1%) on CPI-ritonavir remained on assigned treatment until week 48. At week 48, more patients achieved and maintained treatment response in the tipranavir-ritonavir group than in the CPI-ritonavir group (251 [33.6%] vs 113 [15.3%]; p<0.0001). Median time to treatment failure was significantly longer in the tipranavir-ritonavir group than in the CPI-ritonavir group (113 days vs 0 days; p<0.0001). Gastrointestinal system disorders and raised transaminase, cholesterol, and triglycerides were more frequent in the tipranavir-ritonavir group than in the CPI-ritonavir group. INTERPRETATION: Compared with CPI-ritonavir, tipranavir-ritonavir with an optimised background regimen provides better virological and immunological responses over 48 weeks in patients who have received extensive previous antiretroviral treatment.

Adult↗
PubMed2006

Inhibition of HIV-1 replication by RNA interference of p53 expression.

p53 expression and activation have been associated to faster human immunodeficiency virus (HIV) disease progression, most probably by inducing CD4+ T cell death but also through its cooperative effect in the control of viral gene transcription by viral regulatory proteins. Here, we show that RNA interference of p53 in HIV-1 reporter (HeLa P4-R5 MAGI) and lymphoid (SupT1) cell lines blocked HIV-1 and Tat-induced transcription from the HIV-1 promoter and HIV-1 replication in acutely infected cells, suggesting a cooperative role of p53 in HIV-1 transcription. Contrary to SupT1 cells, which encode several mutations on the p53 DNA binding domain, death of HIV-1-induced syncytia was reduced in cocultures of HeLa P4-R5 MAGI with persistently infected HIV-1 cells. To our knowledge, this is the first demonstration of the effect of the loss of function of p53 in HIV-1 replication, which is independent on its classical DNA binding activity. Our results suggest two independent roles for p53 in HIV-1 infection: cooperation in HIV long-terminal repeat transcription and virus-induced cell death.

Cell Death↗
PubMed2006

Benefits and concerns of simplification strategies in HIV-infected patients.

Highly active antiretroviral therapies (HAART) provide sustained viral control in most patients, but many of these regimens are restricted by complex dosing, drug-drug interactions and toxicities. Numerous strategies of simplified treatment have been explored in order to improve patient quality of life and adherence to treatment, as well as to manage drug-related toxicities while maintaining viral suppression. The first simplification strategy involved switching from protease inhibitors (PIs) to non-nucleoside reverse transcriptase inhibitors (NNRTIs), with an additional benefit on lipid metabolism. The development of once-daily drugs or co-formulated combinations has successfully been used to further simplify treatment. However, studies assessing triple nucleoside regimens have shown a higher frequency of viral failure in comparison with standard HAART, mainly in patients with previous sequential suboptimal treatments. Finally, NRTI-sparing approaches, consisting of NNRTI+PI combinations or monotherapies with boosted PIs, are alternatives to avoid NRTI-related mitochondrial toxicities. An accurate analysis of each patient's history will be necessary in each case to determine whether a simplification strategy is appropriate.

Anti-HIV Agents↗
PubMed2006

Human cytomegalovirus infection is associated with increased proportions of NK cells that express the CD94/NKG2C receptor in aviremic HIV-1-positive patients.

In healthy blood donors, serological positivity for human cytomegalovirus (HCMV) is associated with an increased proportion of NK cells bearing the CD94/NKG2C NK cell receptor (NKR). The expression of the activating CD94/NKG2C NKR and of the inhibitory CD94/NKG2A NKR was studied in a cohort of 45 aviremic human immunodeficiency virus type 1 (HIV-1)-positive patients receiving highly active antiretroviral therapy. The proportions of NKG2C+ NK cells were significantly increased in HIV-1-positive patients (mean +/- SD, 25.9% +/- 23.0%), compared with those in 31 healthy individuals (mean +/- SD, 16.1% +/- 20.7%). Yet, the association vanished when HCMV serological status was considered in a multivariate regression model. These results support the conclusion that changes in the NKR repertoire in HIV1-positive patients are related to a concomitant HCMV infection.

Adult↗
PubMed2006

High prevalence of human papillomavirus infection in the anus, penis and mouth in HIV-positive men.

Human papillomavirus (HPV) types are associated with squamous cell cancers. HIV infection is linked with a higher prevalence of anal HPV infection. It is important to assess whether HPV is present in other body parts involved in sexual practices to establish a cancer prevention program. A high prevalence of high-risk HPV types was present in the anus, penis and mouth (78, 36 and 30%, respectively) in a cohort of HIV-infected males (men who have sex with men and heterosexual), without evidence of pathology in these areas.

AIDS-Related Opportunistic Infections↗
PubMed2006

Constraints on HIV-1 evolution and immunodominance revealed in monozygotic adult twins infected with the same virus.

The predictability of virus-host interactions and disease progression in rapidly evolving human viral infections has been difficult to assess because of host and genetic viral diversity. Here we examined adaptive HIV-specific cellular and humoral immune responses and viral evolution in adult monozygotic twins simultaneously infected with the same virus. CD4 T cell counts and viral loads followed similar trajectories over three years of follow up. The initial CD8 T cell response targeted 17 epitopes, 15 of which were identical in each twin, including two immunodominant responses. By 36 months after infection, 14 of 15 initial responses were still detectable in both, whereas all new responses were subdominant and remained so. Of four responses that declined in both twins, three demonstrated mutations at the same residue. In addition, the evolving antibody responses cross-neutralized the other twin's virus, with similar changes in the pattern of evolution in the envelope gene. These results reveal considerable concordance of adaptive cellular and humoral immune responses and HIV evolution in the same genetic environment, suggesting constraints on mutational pathways to HIV immune escape.

Adult↗
PubMed2006

The effect of atorvastatin treatment on HIV-1-infected patients interrupting antiretroviral therapy.

We conducted a pilot study to assess the effect of atorvastatin on HIV replication. Patients with stable HAART-controlled infection interrupted therapy and were randomly assigned to a control group or to start atorvastatin 40 or 80 mg/day. Statin groups showed lower serum cholesterol but similar viral loads and CD4 T-cell counts to the control group at weeks 4 and 12. Paradoxically, baseline serum cholesterol, but not atorvastatin, influenced viral rebound at week 4.

Anticholesteremic Agents↗
PubMed2006

Inhibition of human immunodeficiency virus type 1 infection in macrophages by an alpha-v integrin blocking antibody.

Macrophages are key cells for HIV infection and HIV spreading inside the organism. Macrophages cultured in vitro can be successfully infected after differentiation with cytokines such as macrophage colony stimulating factor (M-CSF). In the monocyte to macrophage differentiation process with M-CSF, alphav-integrins are upregulated concomitantly with the capacity of HIV to generate a productive virus infection. In the present study we show that an anti-alphav antibody, 17E6, inhibited HIV-1 infection of primary macrophages. The effect of 17E6 on HIV-1 BaL replication in acutely infected macrophages was dose-dependent, with a 50% effective concentration (EC50) of 17+/-2 microg/ml in the absence of cytotoxicity. Similarly, a monoclonal antibody targeting the alphavbeta6 integrin (14D9.F8) also inhibited HIV-1 BaL infection in this cell type. 17E6 reduced the detection of HIV-1 BaL proviral DNA in acutely infected macrophages, but was completely ineffective against HIV-1 BaL production in chronically infected macrophages, suggesting that 17E6 inhibited HIV infection at an early stage of the virus cycle. Finally, a small molecular weight antagonist of the alphavbeta6 integrin, EMD 409849, reduced HIV replication at subtoxic concentrations. Therefore, our results suggest that alphav-containing integrins could play a role in HIV replication in macrophages and suggest that small-molecular-weight compounds might interfere with HIV replication in macrophages through the interaction with alphav integrins.

Antibodies, Monoclonal↗