Response to antiretroviral treatment in HIV-1-infected individuals with allelic variants of the multidrug resistance transporter 1: a pharmacogenetics study.

BACKGROUND:HIV-1-infected patients vary considerably by their response to antiretroviral treatment, drug concentrations in plasma, toxic events, and rate of immune recovery. This variability could have a genetic basis. We did a pharmacogenetics study to analyse the association between response to antiretroviral treatment and allelic variants of several genes. METHODS:In 123 patients, we did PCR analyses of the gene for the multidrug-resistance transporter (MDR1), which codes for P-glycoprotein, of genes coding for isoenzymes of cytochrome P450, CYP3A4, CYP3A5, CYP2D6, and CYP2C19, and of the gene for the chemokine receptor CCR5. We measured concentrations in plasma of the antiretroviral agents efavirenz and nelfinavir by high-performance liquid-chromatography, and measured levels of P-glycoprotein expression, CD4-cell count, and HIV-1 viraemia. FINDINGS: Median drug concentrations in patients with the MDR1 3435 TT, CT, and CC genotypes were at the 30th, 50th, and 75th percentiles, respectively (p=0.0001). In patients with CYP2D6 extensive-metaboliser or poor-metaboliser alleles, median drug concentrations were at percentiles 45 and 62.5, respectively (p=0.04). Patients with the MDR1 TT genotype 6 months after starting treatment had a greater rise in CD4-cell count (257 cells/microL) than patients with the CT (165 cells/microL) and CC (121 cells/microL) genotype (p=0.0048), and the best recovery of naïve CD4-cells. INTERPRETATION:The polymorphism MDR1 3435 C/T predicts immune recovery after initiation of antiretroviral treatment. This finding suggests that P-glycoprotein has an important role in admittance of antiretroviral drugs to restricted compartments in vivo.

Impact of Antibiotic Use on Carbapenem Resistance in Pseudomonas aeruginosa: Is There a Role for Antibiotic Diversity?

In this study, we aimed to evaluate the relationship between the rates of resistance of Pseudomonas aeruginosa to carbapenems and the levels and diversity of antibiotic consumption. Data were retrospectively collected from 20 acute care hospitals across 3 regions of Switzerland between 2006 and 2010. The main outcome of the present study was the rate of resistance to carbapenems among P. aeruginosa. Putative predictors included the total antibiotic consumption and carbapenem consumption in defined daily doses per 100 bed days, the proportion of very broad-spectrum antibiotics used, and the Peterson index. The present study confirmed a correlation between carbapenem use and carbapenem resistance rates at the hospital and regional levels. The impact of diversifying the range of antibiotics used against P. aeruginosa resistance was suggested by (i) a positive correlation in multivariate analysis between the above-mentioned resistance and the proportion of consumed antibiotics having a very broad spectrum of activity (coefficient = 1.77; 95% confidence interval, 0.58 to 2.96; P < 0.01) and (ii) a negative correlation between the resistance and diversity of antibiotic use as measured by the Peterson homogeneity index (coefficient = -0.52; P < 0.05). We conclude that promoting heterogeneity plus parsimony in the use of antibiotics appears to be a valuable strategy for minimizing the spread of carbapenem resistance in P. aeruginosa in hospitals.

PPARβ/δ prevents endoplasmic reticulum stress-associated inflammation and insulin resistance in skeletal muscle cells through an AMPK-dependent mechanism.

AIM/HYPOTHESIS: Endoplasmic reticulum (ER) stress, which is involved in the link between inflammation and insulin resistance, contributes to the development of type 2 diabetes mellitus. In this study, we assessed whether peroxisome proliferator-activated receptor (PPAR)β/δ prevented ER stress-associated inflammation and insulin resistance in skeletal muscle cells. METHODS: Studies were conducted in mouse C2C12 myotubes, in the human myogenic cell line LHCN-M2 and in skeletal muscle from wild-type and PPARβ/δ-deficient mice and mice exposed to a high-fat diet. RESULTS: The PPARβ/δ agonist GW501516 prevented lipid-induced ER stress in mouse and human myotubes and in skeletal muscle of mice fed a high-fat diet. PPARβ/δ activation also prevented thapsigargin- and tunicamycin-induced ER stress in human and murine skeletal muscle cells. In agreement with this, PPARβ/δ activation prevented ER stress-associated inflammation and insulin resistance, and glucose-intolerant PPARβ/δ-deficient mice showed increased phosphorylated levels of inositol-requiring 1 transmembrane kinase/endonuclease-1α in skeletal muscle. Our findings demonstrate that PPARβ/δ activation prevents ER stress through the activation of AMP-activated protein kinase (AMPK), and the subsequent inhibition of extracellular-signal-regulated kinase (ERK)1/2 due to the inhibitory crosstalk between AMPK and ERK1/2, since overexpression of a dominant negative AMPK construct (K45R) reversed the effects attained by PPARβ/δ activation. CONCLUSIONS/INTERPRETATION: Overall, these findings indicate that PPARβ/δ prevents ER stress, inflammation and insulin resistance in skeletal muscle cells by activating AMPK.

The ubiquitin-proteasome system in prostate cancer and its transition to castration resistance.

Prostate cancer is the most common carcinoma in the male population. In its initial stage, the disease is androgen-dependent and responds therapeutically to androgen deprivation treatment but it usually progresses after a few years to an androgen-independent phase that is refractory to hormonal manipulations. The proteasome is a multi-unit protease system that regulates the abundance and function of a significant number of cell proteins, and its inhibition results in cancer cell growth inhibition and apoptosis and is already exploited in the clinic with the use of proteasome inhibitor bortezomib in multiple myeloma. In order to be recognized by the proteasome, a target protein needs to be linked to a chain of the small protein ubiquitin. In this paper, we review the role of ubiquitin-proteasome system (UPS) in androgen receptor-dependent transcription as well as in the castration resistant stage of the disease, and we discuss therapeutic opportunities that UPS inhibition offers in prostate cancer.

Computed tomography angiography vs 3 T black-blood cardiovascular magnetic resonance for identification of symptomatic carotid plaques.

BACKGROUND: The purpose of this prospective study was to perform a head-to-head comparison of the two methods most frequently used for evaluation of carotid plaque characteristics: Multi-detector Computed Tomography Angiography (MDCTA) and black-blood 3 T-cardiovascular magnetic resonance (bb-CMR) with respect to their ability to identify symptomatic carotid plaques. METHODS: 22 stroke unit patients with unilateral symptomatic carotid disease and >50% stenosis by duplex ultrasound underwent MDCTA and bb-CMR (TOF, pre- and post-contrast fsT1w-, and fsT2w- sequences) within 15 days of symptom onset. Both symptomatic and contralateral asymptomatic sides were evaluated. By bb-CMR, plaque morphology, composition and prevalence of complicated AHA type VI lesions (AHA-LT6) were evaluated. By MDCTA, plaque type (non-calcified, mixed, calcified), plaque density in HU and presence of ulceration and/or thrombus were evaluated. Sensitivity (SE), specificity (SP), positive and negative predictive value (PPV, NPV) were calculated using a 2-by-2-table. RESULTS: To distinguish between symptomatic and asymptomatic plaques AHA-LT6 was the best CMR variable and presence / absence of plaque ulceration was the best CT variable, resulting in a SE, SP, PPV and NPV of 80%, 80%, 80% and 80% for AHA-LT6 as assessed by bb-CMR and 40%, 95%, 89% and 61% for plaque ulceration as assessed by MDCTA. The combined SE, SP, PPV and NPV of bb-CMR and MDCTA was 85%, 75%, 77% and 83%, respectively. CONCLUSIONS: Bb-CMR is superior to MDCTA at identifying symptomatic carotid plaques, while MDCTA offers high specificity at the cost of low sensitivity. Results were only slightly improved over bb-CMR alone when combining both techniques.

Periprocedural Hemodynamic Depression Is Associated With a Higher Number of New Ischemic Brain Lesions After Stenting in the International Carotid Stenting Study-MRI Substudy.

BACKGROUND AND PURPOSE: Carotid artery stenting (CAS) is associated with a higher risk of both hemodynamic depression and new ischemic brain lesions on diffusion-weighted imaging than carotid endarterectomy (CEA). We assessed whether the occurrence of hemodynamic depression is associated with these lesions in patients with symptomatic carotid stenosis treated by CAS or CEA in the randomized International Carotid Stenting Study (ICSS)-MRI substudy. METHODS: The number and total volume of new ischemic lesions on diffusion-weighted imaging 1 to 3 days after CAS or CEA was measured in the ICSS-MRI substudy. Hemodynamic depression was defined as periprocedural bradycardia, asystole, or hypotension requiring treatment. The number of new ischemic lesions was the primary outcome measure. We calculated risk ratios and 95% confidence intervals per treatment with Poisson regression comparing the number of lesions in patients with or without hemodynamic depression. RESULTS: A total of 229 patients were included (122 allocated CAS; 107 CEA). After CAS, patients with hemodynamic depression had a mean of 13 new diffusion-weighted imaging lesions, compared with a mean of 4 in those without hemodynamic depression (risk ratio, 3.36; 95% confidence interval, 1.73-6.50). The number of lesions after CEA was too small for reliable analysis. Lesion volumes did not differ between patients with or without hemodynamic depression. CONCLUSIONS: In patients treated by CAS, periprocedural hemodynamic depression is associated with an excess of new ischemic lesions on diffusion-weighted imaging. The findings support the hypothesis that hypoperfusion increases the susceptibility of the brain to embolism. CLINICAL TRIAL REGISTRATION URL: http://www.controlled-trials.com. Unique identifier: ISRCTN25337470.

Divergent functions of three Candida albicans zinc-cluster transcription factors (CTA4, ASG1 and CTF1) complementing pleiotropic drug resistance in Saccharomyces cerevisiae.

One of the mediators of pleiotropic drug resistance in Saccharomyces cerevisiae is the ABC-transporter gene PDR5. This gene is regulated by at least two transcription factors with Zn(2)-Cys(6) finger DNA-binding motifs, Pdr1p and Pdr3p. In this work, we searched for functional homologues of these transcription factors in Candida albicans. A C. albicans gene library was screened in a S. cerevisiae mutant lacking PDR1 and PDR3 and clones resistant to azole antifungals were isolated. From these clones, three genes responsible for azole resistance were identified. These genes (CTA4, ASG1 and CTF1) encode proteins with Zn(2)-Cys(6)-type zinc finger motifs in their N-terminal domains. The C. albicans genes expressed in S. cerevisiae could activate the transcription of a PDR5-lacZ reporter system and this reporter activity was PDRE-dependent. They could also confer resistance to azoles in a S. cerevisiae strain lacking PDR1, PDR3 and PDR5, suggesting that CTA4-, ASG1- and CTF1-dependent azole resistance can be caused by genes other than PDR5 in S. cerevisiae. Deletion of CTA4, ASG1 and CTF1 in C. albicans had no effect on fluconazole susceptibility and did not alter the expression of the ABC-transporter genes CDR1 and CDR2 or the major facilitator gene MDR1, which encode multidrug transporters known as mediators of azole resistance in C. albicans. However, additional phenotypic screening tests on the C. albicans mutants revealed that the presence of ASG1 was necessary to sustain growth on non-fermentative carbon sources (sodium acetate, acetic acid, ethanol). In conclusion, C. albicans possesses functional homologues of the S. cerevisiae Pdr1p and Pdr3p transcription factors; however, their properties in C. albicans have been rewired to other functions.

HIV type 1 drug resistance among naive patients from Venezuela.

In this study, we characterize proviral DNA of 20 HIV-1 asymptomatic antiretroviral-naive patients from Venezuela in env, gag, and pol genes regions. Results from both env/gag HMA subtyping and phylogenetic analysis of pol partial sequences led to the description of clade B in all cases. Nevertheless, the high prevalence of polymorphisms was particularly evident among the protease sequences. A 10% prevalence of major resistance mutations to RTIs was found. Our data also suggested that the protease polymorphisms I62T and V77T could be considered as molecular markers of the subtype B local epidemic. In addition, we show how proviral DNA can be used as a reliable tool to follow trends of resistance mutation transmission.

Association between circulating cytokine levels, diabetes and insulin resistance in a population-based sample (CoLaus study).

OBJECTIVE: The associations between inflammation, diabetes and insulin resistance remain controversial. Hence, we assessed the associations between diabetes, insulin resistance (using HOMA-IR) and metabolic syndrome with the inflammatory markers high-sensitive C-reactive protein (hs-CRP), interleukin-1 beta (IL-1β), interleukin-6 (IL-6) and tumour necrosis factor-α (TNF-α). DESIGN: Cross-sectional study. PARTICIPANTS: Two thousand eight hundred and eighty-four men and 3201 women, aged 35-75, participated in this study. METHODS: C-reactive protein was assessed by immunoassay and cytokines by multiplexed flow cytometric assay. In a subgroup of 532 participants, an oral glucose tolerance test (OGTT) was performed to screen for impaired glucose tolerance (IGT). RESULTS: IL-6, TNF-α and hs-CRP were significantly and positively correlated with fasting plasma glucose (FPG), insulin and HOMA-IR. Participants with diabetes had higher IL-6, TNF-α and hs-CRP levels than participants without diabetes; this difference persisted for hs-CRP after multivariate adjustment. Participants with metabolic syndrome had increased IL-6, TNF-α and hs-CRP levels; these differences persisted after multivariate adjustment. Participants in the highest quartile of HOMA-IR had increased IL-6, TNF-α and hs-CRP levels; these differences persisted for TNF-α and hs-CRP after multivariate adjustment. No association was found between IL-1β levels and all diabetes and insulin resistance markers studied. Finally, participants with IGT had higher hs-CRP levels than participants with a normal OGTT, but this difference disappeared after controlling for body mass index (BMI). CONCLUSION: We found that subjects with diabetes, metabolic syndrome and increased insulin resistance had increased levels of IL6, TNF-α and hs-CRP, while no association was found with IL-1β. The increased inflammatory state of subjects with IGT is partially explained by increased BMI.

Pregnancy impairs resistance of C57BL/6 mice to Leishmania major infection.

To determine if gestational factors affect the severity of L. major infection, this study assessed the levels of IL-4 mRNA and IFN-gamma mRNA in popliteal lymph node cells of pregnant C57BL/6 mice mated at 5 hours, 16 hours and 15 days post L. major infection using PCR. Infected pregnant C57BL/6 mice developed larger cutaneous footpad lesions compared with non-pregnant infected C57BL/6 mice. The resolution of footpad lesions commenced after 8th week in C57BL/6 mice mated at 16 hrs post L. major infection but 12 weeks in C57BL/6 mice mated at 5 hrs and 15 days post L. major infection. C57BL/6 mice that were infected 20 days post partum resolved L. major infection effectively. But, the lesions in infected pregnant C57BL/6 mice and infected non-pregnant C57BL/6 mice were not as large as in susceptible BALB/c mice. The mean litter weights were similar in pregnant infected C57BL/6 mice mated at different stages of L. major infection but were slightly lower than weights of litters from pregnant uninfected C57BL/6 mice. In 5 days infected pregnant C57BL/6 mice, the levels of IFN-gamma were raised compared with the levels of IL-4 but those mated at 15 days post L. major infection had highest level of IFN-gamma mRNA. In 10 days pregnant infected C57BL/6 mice, levels of IL-4 were raised compared with IFN-gamma but mice mated at 16 hrs post L. major infection had highest level of IL-4. In 15 days pregnant infected mice, the levels of IL-4 were higher than IFN-gamma irrespective of the stage of L. major infection when the mice were mated. Mice infected with L. major 20 days post-partum produced more IFN-gamma than IL-4 from 16 hrs post L. major infection onwards. It may be concluded that increased IL-4 in pregnant infected C57BL/6 mice impairs the resistance of C57BL/6 mice to L. major infection especially in mice that were pregnant before effective immunity (5 hours post L. major infection) is mounted against L. major infection.

Endothelial nitric oxide synthase gene transfer restores endothelium-dependent relaxations and attenuates lesion formation in carotid arteries in apolipoprotein E-deficient mice.

Nitric oxide (NO) and monocyte chemoattractant protein-1 (MCP-1) exert partly opposing effects in vascular biology. NO plays pleiotropic vasoprotective roles including vasodilation and inhibition of platelet aggregation, smooth muscle cell proliferation, and endothelial monocyte adhesion, the last effect being mediated by MCP-1 downregulation. Early stages of arteriosclerosis are associated with reduced NO bioactivity and enhanced MCP-1 expression. We have evaluated adenovirus-mediated gene transfer of human endothelial NO synthase (eNOS) and of a N-terminal deletion (8ND) mutant of the MCP-1 gene that acts as a MCP-1 inhibitor in arteriosclerosis-prone, apolipoprotein E-deficient (ApoE(-/-)) mice. Endothelium-dependent relaxations were impaired in carotid arteries instilled with a noncoding adenoviral vector but were restored by eNOS gene transfer (p < 0.01). A perivascular collar was placed around the common carotid artery to accelerate lesion formation. eNOS gene transfer reduced lesion surface areas, intima/media ratios, and macrophage contents in the media at 5-week follow-up (p < 0.05). In contrast, 8ND-MCP-1 gene transfer did not prevent lesion formation. In conclusion, eNOS gene transfer restores endothelium-dependent vasodilation and inhibits lesion formation in ApoE(-/-) mouse carotids. Further studies are needed to assess whether vasoprotection is maintained at later disease stages and to evaluate the long-term efficacy of eNOS gene therapy for primary arteriosclerosis.

Development of glycopeptide-intermediate resistance by Staphylococcus aureus leads to attenuated infectivity in a rat model of endocarditis.

Glycopeptide-intermediate resistant Staphylococcus aureus (GISA) are characterized by multiple changes in the cell wall and an altered expression of global virulence regulators. We investigated whether GISA are affected in their infectivity in a rat model of experimental endocarditis. The glycopeptide-susceptible, methicillin-resistant S. aureus M1V2 and its laboratory-derived GISA M1V16 were examined for their ability to (i) adhere to fibrinogen and fibronectin in vitro, (ii) persist in the bloodstream after intravenous inoculation, (iii) colonize aortic vegetations in rats, and (iv) compete for valve colonization by co-inoculation. Both GISA M1V16 and M1V2 adhered similarly to fibrinogen and fibronectin in vitro. In rats, GISA M1V16 was cleared faster from the blood (P < 0.05) and required 100-times more bacteria than parent M1V2 (10(6) versus 10(4)CFU) to infect 90% of vegetations. GISA M1V16 also had 100 to 1000-times lower bacterial densities in vegetations. Moreover, after co-inoculation with GISA M1V16 and M1V2Rif, a rifampin-resistant variant of M1V2 to discriminate them in organ cultures, GISA M1V16 was out-competed by the glycopeptide-susceptible counterpart. Thus, in rats with experimental endocarditis, GISA showed an attenuated virulence, likely due to a faster clearance from the blood and a reduced fitness in cardiac vegetations. The GISA phenotype appeared globally detrimental to infectivity.