34 research outputs found
Determination of P-glycoprotein surface expression and functional ability after in vitro treatment with darunavir or raltegravir in lymphocytes of healthy donors
No full textIt has been shown that P-glycoprotein (P-gp) can greatly affect the cell uptake of antiretroviral drugs, thus hampering their access to HIV-1 replication sites. Lymphocytes are important sites of replication of HIV and target of other drugs, modification on these cells of P-gp could have an effect on pharmacokinetic of antiretrovirals and drug substrates. Blood samples from 16 healthy volunteers were used to determine the expression of P-gp on total, land T helper lymphocytes after exposure to darunavir, a second generation protease inhibitor, and raltegravir, the first approved integrase inhibitor. Moreover, the effect of the drugs on P-gp functional activity was also studied by the rhodamine-123 efflux test. Darunavir, but not raltegravir, exposure caused a moderate, dose-dependent increment in P-gp expression in total, T and T helper lymphocytes, as demonstrated by the relative frequency of P-gp + cells and by the amount of P-gp molecules present on cell surface. Functionally, incubation with darunavir led to a marked inhibition of P-gp activity measured by the efflux of rhodamine-123 similar to that observed by verapamil, a specific P-gp inhibitor. Raltegravir was not able to modify the efflux of rhodamine-123 level. Data show that darunavir, unlike raltegravir, may modify the expression and functionality of P-gp on human lymphocytes, thus leading to potential changes in intracellular concentrations of darunavir in patients treated with other drugs substrate of P-gp and vice versa. Our study highlights the need for studies on drug interactions via the P-gp modulation mechanism, especially with the current multi-drug regimens. (C) 2013 Elsevier B.V. All rights reserved
Vitamin D as Modulator of Drug Concentrations: A Study on Two Italian Cohorts of People Living with HIV Administered with Efavirenz
No full textTo date, vitamin D seems to have a significant role in affecting the prevention and immunomodulation in COVID-19 disease. Nevertheless, it is important to highlight that this pro-hormone has other several activities, such as affecting drug concentrations, since it regulates the expression of cytochrome P450 (CYP) genes. Efavirenz (EFV) pharmacokinetics is influenced by CYPs, but no data are available in the literature concerning the association among vitamin D levels, seasonality (which affects vitamin D concentrations) and EFV plasma levels. For this reason, the aim of this study was to evaluate the effect of 25-hydroxy vitamin D (25(OH)D3) levels on EFV plasma concentrations in different seasons. We quantified 25(OH)D3 by using chemiluminescence immunoassay, whereas EFV plasma concentrations were quantified with the HPLC–PDA method. A total of 316 patients were enrolled in Turin and Rome. Overall, 25(OH)D3levels resulted in being inversely correlated with EFV concentrations. Some patients with EFV levels higher than 4000 ng/mL showed a deficient 25(OH)D3 concentration in Turin and Rome cohorts and together. EFV concentrations were different in patients without vitamin D supplementation, whereas, for vitamin D-administered individuals, no difference in EFV exposure was present. Concerning seasonality, EFV concentrations were associated with 25(OH)D3 deficiency only in winter and in spring, whereas a significant influence was highlighted for 25(OH)D3 stratification for deficient, insufficient and sufficient values in winter, spring and summer. A strong and inverse association between 25(OH)D3and EFV plasma concentrations was suggested. These data suggest that vitamin D is able to affect drug exposure in different seasons; thus, the achievement of the clinical outcome could be improved by also considering this pro-hormone
Stable Virologic Suppression during Raltegravir plus Atazanavir Dual-Therapy Taken Every other Day: A Case Report
No full textAdherence to Highly Active Antiretroviral Therapy can be affected by a number of factors limiting the outcome of the treatment. We report the case of a 39 year-old HIV-HCV co-infected woman in stable virologic suppression and immune recovery during a raltegravir plus unboosted atazanavir dual-therapy taken every other day. Measurement of HIV-1 RNA plasma levels (viral load), CD4+ T-cell counts and the therapeutic drug monitoring through validated high-performance liquid chromatography methods, were performed to assess the effectiveness of this regimen. Our data on raltegravir pharmacokinetics in association with atazanavir show adequate minimum effective concentrations of raltegravir throughout 36 and 48 hours despite the every other day intake of the drug. Further studies are recommended in order to identify the determinants that could enable a reduction in antiretroviral dosing frequency in case of difficult management of HIV-infected patients due to low adherence to therapy. By reporting our medical experience, we focused on the utility of performing therapeutic drug monitoring especially in cases of poor adherence, drug and/or alcohol abuse, co morbidities and co-administration of other drugs
Analysis of single-nucleotide polymorphisms (SNPs) in human CYP3A4 and CYP3A5 genes: potential implications for the metabolism of HIV drugs
No full textBackground: Drug metabolism via the cytochrome P450 (CYP450) system has emerged as an important
determinant in the occurrence of several drug interactions (adverse drug reactions, reduced pharmacological effect,
drug toxicities). In particular, CYP3A4 and CYP3A5 (interacting with more than 60% of licensed drugs) exhibit the
most individual variations of gene expression, mostly caused by single nucleotide polymorphisms (SNPs) within the
regulatory region of the CYP3A4 and CYP3A5 genes which might affect the level of enzyme production.
In this study, we sought to improve the performance of sensitive screening for CYP3A polymorphism detection in
twenty HIV-1 infected patients undergoing lopinavir/ritonavir (LPV/r) monotherapy.
Methods: The study was performed by an effective, easy and inexpensive home-made Polymerase Chain Reaction
Direct Sequencing approach for analyzing CYP3A4 and CYP3A5 genes which can detect both reported and unreported
genetic variants potentially associated with altered or decreased functions of CYP3A4 and CYP3A5 proteins. Proportions
and tests of association were used.
Results: Among the genetic variants considered, CYP3A4*1B (expression of altered function) was only found in 3
patients (15%) and CYP3A5*3 (expression of splicing defect) in 3 other patients (15%). CYP3A5*3 did not appear to
be associated with decreased efficacy of LPV/r in any patient, since none of the patients carrying this variant showed
virological rebound during LPV/r treatment or low levels of TDM. In contrast, low-level virological rebound was
observed in one patient and a low TDM level was found in another; both were carrying CYP3A4*1B.
Conclusions: Our method exhibited an overall efficiency of 100% (DNA amplification and sequencing in our group of
patients). This may contribute to producing innovative results for better understanding the inter-genotypic variability
in gene coding for CYP3A, and investigating SNPs as biological markers of individual response to drugs requiring
metabolism via the cytochrome P450 system
Potential implications of CYP3A4, CYP3A5 and MDR‐1 genetic variants on the efficacy of Lopinavir/Ritonavir (LPV/r) monotherapy in HIV‐1 patients
No full textSeveral genetic single nucleotide polymorphisms (SNPs) in biotransformation enzymes (CYP3A4, CYP3A5) or transporter proteins (multidrug resistance MDR1 gene product, P-gp) are involved in PI metabolism so that PI pharmacokinetics is characterized by a large inter-individual variability. The aim of this study was: (i) to develop an in-house PCR/direct sequencing, based on DNA purification of full-length CYP3A4 and CYP3A5 genes (SNPs) and MDR1 C3435T variant; (ii) to investigate association of CYP3A4 and CYP3A5 reported or unreported genetic polymorphisms and MDR1-C3435T (CC homozygote, CT heterozygote, TT homozygote) with clinical outcome of HIV-1 infected subjects treated with PI.Methods: Overall, 39 HIV-1 infected patients receiving boosted Lopinavir (LPV/r) monotherapy after virological suppression were
genotyped and analyzed through PCR and direct sequencing of full-length CYP3A4 and CYP3A5 gene sequences [1] and MDR1
gene (C3435T). CD4T-cell counts and plasma viral load were analyzed before and after LPV/r initiation; LPV/r therapeutic drug
monitoring (TDM) was determined at 12-hours.
Results: LPV/r TDM (ng/ml) did not show significant differences among CYP3A4 or CYP3A5 SNPs, although a mean lower level of
LPV/r was associated with detection of several SNPs: CYP3A5*3 rs776746; CYP3A5 rs28365088, CYP3A5 rs15524, CYP3A4
rs2687116, and a not already described polymorphism CYP3A4 nt20338. In follow-up analysis, B90% adherence was the main
factor associated with virological failure of LPV/r monotherapy (83.3% of failure vs 34.4%, pB0.001 at log-rank test). Adjusting
for adherence, the detection of a single CYP3A5*3 rs776746 and CYP3A5 rs15524 SNPs was associated with higher probability of
LPV/r monotherapy failure (pB0.01), and in general, detection of any CYP3A5 SNP was associated with failure (26.2% vs 58.3%,
p0.067). No-association with detection of any CYP3A4 SNPs was found. MDR1 TT variants showed significant lower frequency
of treatment failure (0.0% vs 47.7%, p0.026), since non-TT homozygote patient failed LPV/r monotherapy.
Conclusions: Efficacy of PI monotherapy is strongly dependent from patient adherence, but, in adherent patients, genetic
factors, such as CYP3A5 and MDR1-C3435T gene variants, may affect the response to treatment, though their role, as well of
other genetic variants, need further investigation
Altered brain cholesterol/isoprenoid metabolism in a rat model of autism spectrum disorders
No full textAutism spectrum disorders (ASDs) present a wide range of symptoms characterized by altered sociability, compromised communication and stereotypic/repetitive behaviors. These symptoms are caused by developmental changes, but the mechanisms remain largely unknown. Some lines of evidence suggest an impairment of the cholesterol/isoprenoid metabolism in the brain as a possible cause, but systematic analyses in rodent models of ASDs are lacking. Prenatal exposure to the antiepileptic drug valproate (VPA) is a risk factor for ASDs in humans and generates a well-established model for the disease in rodents. Here, we studied cholesterol/isoprenoid metabolism in different brain areas of infant, adolescent and adult rats prenatally exposed to VPA. VPA-treated rats present autistic-like symptoms, they show changes in cholesterol/isoprenoid homeostasis in some brain areas, a decreased number of oligodendrocytes and impaired myelination in the hippocampus. Together, our data suggest a relation between brain cholesterol/isoprenoid homeostasis and ASDs
Granulocytic myeloid derived suppressor cells expansion during active pulmonary tuberculosis is associated with high nitric oxide plasma level
No full textTuberculosis (TB) is still the principal cause of death caused by a single infectious agent, and the balance between the bacillus and host defense mechanisms reflects the different manifestations of the pathology. The aim of this work was to study the role of myeloid-derived suppressor cells (MDSCs) during active pulmonary tuberculosis at the site of infection. We observed an expansion of MDSCs in the lung and blood of patients with active TB, which are correlated with an enhanced amount of nitric oxide in the plasma. We also found that these cells have the remarkable ability to suppress T-cell response, suggesting an important role in the modulation of the immune response against TB. Interestingly, a trend in the diminution of MDSCs was found after an efficacious anti-TB therapy, suggesting that these cells may be used as a potential biomarker for monitoring anti-TB therapy efficacy
Multicompartment vectors as novel drug delivery systems: Selective activation of Tγδ lymphocytes after zoledronic acid delivery
No full textMulticompartment nanoscopic carriers can be easily assembled by inducing the aggregation of anionic "hybrid" niosomes by means of cationic biocompatible polyelectrolytes. The resulting vesicle clusters, whose size and overall net charge can be easily controlled by varying the polyelectrolyte-to-particle charge ratio, show an interesting potential for multidrug delivery. In this article we provide strong evidence for their effective use in vitro as multicompartment vectors selectively directed toward monocyte/macrophage cells, showing that the monocyte/macrophage-mediated activation of Tγδ lymphocytes induced by zoledronic acid is enhanced by a factor 103 when the zoledronic acid is intracellularly delivered through these carriers. Furthermore, the multicompartment ε-polylysine niosome clusters, with their intrinsic selectivity toward macrophages, appear particularly suitable for implementing therapeutic strategies against chronically infected macrophages. From the Clinical Editor: ε-polylysine niosome clusters, with their intrinsic selectivity toward macrophages, offer the potential for multidrug delivery. The effectiveness of aminobisphosphonate zoledronate is demonstrated to enhance the recruitment of Tγδ lymphocytes by macrophages by 2 orders of magnitude, suggesting a new therapeutic strategy for addressing pathologies featuring chronically infected macrophages. © 2011 Elsevier Inc
Determination of antituberculosis drug concentration in human plasma by MALDI-TOF/TOF
No full textTherapeutic drug monitoring allows to determine the best dosage regimen adapted to each patient optimizing the therapeutic benefits, while minimizing the risk for side effects. Here, the first methodological approach based on matrix-assisted laser desorption/ionization source equipped with tandem time-of-flight (MALDI-TOF/TOF) mass spectrometry for the determination of the antituberculosis (anti-TB) drugs ethambutol, pyrazinamide, rifampicin, and streptomycin concentration in the plasma of tuberculosis-infected patients is reported. The volume of the plasma sample was 200 microL. Plasma samples were cleaned-up by protein precipitation and evaporated in a water bath under a nitrogen stream. The extracted samples were reconstituted with 200 microL of 50% methanol-0.03% formic acid solution (v/v), spiked with known amounts of anti-TB drugs, mixed (1:1) with a saturated matrix solution (4-hydroxybenzoic acid in 50% acetonitrile-0.1% trifluoracetic acid solution; v/v), and spotted onto the MALDI-TOF/TOF sample target plate. The anti-TB drug concentration was determined by standard additions analysis. Regression of standard additions was linear over the whole anti-TB drug concentration range explored (the final anti-TB drug concentration ranged from 0.20 to 200 pmol/microL). The absolute recovery of the anti-TB drugs ranged between 87 and 110%. The minimal ethambutol, pyrazinamide, rifampicin, and streptomycin concentration detectable by MALDI-TOF/TOF is 0.08, 0.20, 0.12, and 0.15 pmol/microL, respectively
