Coenzyme Q10 levels are low and may be associated with the inflammatory cascade in septic shock

Mitochondrial dysfunction is associated with increased mortality in septic shock. Coenzyme Q10 (CoQ10) is a key cofactor in the mitochondrial respiratory chain, but whether CoQ10 is depleted in septic shock remains unknown. Moreover, statin therapy may decrease CoQ10 levels, but whether this occurs acutely remains unknown. We measured CoQ10 levels in septic shock patients enrolled in a randomized trial of simvastatin versus placebo. We conducted a post hoc analysis of a prospective, randomized trial of simvastatin versus placebo in patients with septic shock (ClinicalTrials.gov ID: NCT00676897). Adult patients with suspected or confirmed infection and the need for vasopressor support were included in the initial trial. For the current analysis, blood specimens were analyzed for plasma CoQ10 and low-density lipoprotein (LDL) levels. The relationship between CoQ10 levels and inflammatory and vascular endothelial biomarkers was assessed using either the Pearson or Spearman correlation coefficient. We analyzed 28 samples from 14 patients. CoQ10 levels were low, with a median of 0.49 (interquartile range 0.26 to 0.62) compared to levels in healthy control patients (CoQ10 = 0.95 μmol/L ± 0.29; P < 0.0001). Statin therapy had no effect on plasma CoQ10 levels over time (P = 0.13). There was a statistically significant relationship between plasma CoQ10 levels and levels of vascular cell adhesion molecule (VCAM) (r2 = 0.2; P = 0.008), TNF-α (r2 = 0.28; P = 0.004), IL-8 (r2 = 0.21; P = 0.015), IL-10 (r2 = 0.18; P = 0.025), E-selectin (r2 = 0.17; P = -0.03), IL-1ra (r2 = 0.21; P = 0.014), IL-6 (r2 = 0.17; P = 0.029) and IL-2 (r2 = 0.23; P = 0.009). After adjusting for LDL levels, there was a statistically significant inverse relationship between plasma CoQ10 levels and levels of VCAM (r2 = 0.24; P = 0.01) (Figure 3) and IL-10 (r2 = 0.24; P = 0.02). CoQ10 levels are significantly lower in septic shock patients than in healthy controls. CoQ10 is negatively associated with vascular endothelial markers and inflammatory molecules, though this association diminishes after adjusting for LDL levels

HIV-1 Entry, Inhibitors, and Resistance

Entry inhibitors represent a new class of antiretroviral agents for the treatment of infection with HIV-1. While resistance to other HIV drug classes has been well described, resistance to this new class is still ill defined despite considerable clinical use. Several potential mechanisms have been proposed: tropism switching (utilization of CXCR4 instead of CCR5 for entry), increased affinity for the coreceptor, increased rate of virus entry into host cells, and utilization of inhibitor-bound receptor for entry. In this review we will address the development of attachment, fusion, and coreceptor entry inhibitors and explore recent studies describing potential mechanisms of resistance

Two HIV-1 Variants Resistant to Small Molecule CCR5 Inhibitors Differ in How They Use CCR5 for Entry

HIV-1 variants resistant to small molecule CCR5 inhibitors recognize the inhibitor-CCR5 complex, while also interacting with free CCR5. The most common genetic route to resistance involves sequence changes in the gp120 V3 region, a pathway followed when the primary isolate CC1/85 was cultured with the AD101 inhibitor in vitro, creating the CC101.19 resistant variant. However, the D1/86.16 escape mutant contains no V3 changes but has three substitutions in the gp41 fusion peptide. By using CCR5 point-mutants and gp120-targeting agents, we have investigated how infectious clonal viruses derived from the parental and both resistant isolates interact with CCR5. We conclude that the V3 sequence changes in CC101.19 cl.7 create a virus with an increased dependency on interactions with the CCR5 N-terminus. Elements of the CCR5 binding site associated with the V3 region and the CD4-induced (CD4i) epitope cluster in the gp120 bridging sheet are more exposed on the native Env complex of CC101.19 cl.7, which is sensitive to neutralization via these epitopes. However, D1/86.16 cl.23 does not have an increased dependency on the CCR5 N-terminus, and its CCR5 binding site has not become more exposed. How this virus interacts with the inhibitor-CCR5 complex remains to be understood

Long-Term Programming of Antigen-Specific Immunity from Gene Expression Signatures in the PBMC of Rhesus Macaques Immunized with an SIV DNA Vaccine

While HIV-1-specific cellular immunity is thought to be critical for the suppression of viral replication, the correlates of protection have not yet been determined. Rhesus macaques (RM) are an important animal model for the study and development of vaccines against HIV/AIDS. Our laboratory has helped to develop and study DNA-based vaccines in which recent technological advances, including genetic optimization and in vivo electroporation (EP), have helped to dramatically boost their immunogenicity. In this study, RMs were immunized with a DNA vaccine including individual plasmids encoding SIV gag, env, and pol alone, or in combination with a molecular adjuvant, plasmid DNA expressing the chemokine ligand 5 (RANTES), followed by EP. Along with standard immunological assays, flow-based activation analysis without ex vivo restimulation and high-throughput gene expression analysis was performed. Strong cellular immunity was induced by vaccination which was supported by all assays including PBMC microarray analysis that identified the up-regulation of 563 gene sequences including those involved in interferon signaling. Furthermore, 699 gene sequences were differentially regulated in these groups at peak viremia following SIVmac251 challenge. We observed that the RANTES-adjuvanted animals were significantly better at suppressing viral replication during chronic infection and exhibited a distinct pattern of gene expression which included immune cell-trafficking and cell cycle genes. Furthermore, a greater percentage of vaccine-induced central memory CD8+ T-cells capable of an activated phenotype were detected in these animals as measured by activation analysis. Thus, co-immunization with the RANTES molecular adjuvant followed by EP led to the generation of cellular immunity that was transcriptionally distinct and had a greater protective efficacy than its DNA alone counterpart. Furthermore, activation analysis and high-throughput gene expression data may provide better insight into mechanisms of viral control than may be observed using standard immunological assays

The HIV Envelope but Not VSV Glycoprotein Is Capable of Mediating HIV Latent Infection of Resting CD4 T Cells

HIV fusion and entry into CD4 T cells are mediated by two receptors, CD4 and CXCR4. This receptor requirement can be abrogated by pseudotyping the virion with the vesicular stomatitis virus glycoprotein (VSV-G) that mediates viral entry through endocytosis. The VSV-G-pseudotyped HIV is highly infectious for transformed cells, although the virus circumvents the viral receptors and the actin cortex. In HIV infection, gp120 binding to the receptors also transduces signals. Recently, we demonstrated a unique requirement for CXCR4 signaling in HIV latent infection of blood resting CD4 T cells. Thus, we performed parallel studies in which the VSV-G-pseudotyped HIV was used to infect both transformed and resting T cells in the absence of coreceptor signaling. Our results indicate that in transformed T cells, the VSV-G-pseudotyping results in lower viral DNA synthesis but a higher rate of nuclear migration. However, in resting CD4 T cells, only the HIV envelope-mediated entry, but not the VSV-G-mediated endocytosis, can lead to viral DNA synthesis and nuclear migration. The viral particles entering through the endocytotic pathway were destroyed within 1–2 days. These results indicate that the VSV-G-mediated endocytotic pathway, although active in transformed cells, is defective and is not a pathway that can establish HIV latent infection of primary resting T cells. Our results highlight the importance of the genuine HIV envelope and its signaling capacity in the latent infection of blood resting T cells. These results also call for caution on the endocytotic entry model of HIV-1, and on data interpretation where the VSV-G-pseudotyped HIV was used for identifying HIV restriction factors in resting T cells

Thermonuclear (type-I) X-ray bursts observed by the Rossi X-ray Timing Explorer

We have assembled a sample of 1187 thermonuclear (type-I) X-ray bursts from 48 accreting neutron stars by the Rossi X-ray Timing Explorer, spanning more than ten years. The sample contains examples of two of the three theoretical ignition regimes and likely examples of the third. We present a detailed analysis of the variation of the burst profiles, energetics, recurrence times, presence of photospheric radius expansion, and presence of burst oscillations, as a function of accretion rate. We estimated the distance for 35 sources exhibiting radius-expansion bursts, and found that the peak flux of such bursts varies typically by 13%. We classified sources into two main groups based on the burst properties: both long and short bursts (indicating mixed H/He accretion), and consistently short bursts (primarily He accretion). The decrease in burst rate observed for both groups at >0.06 Mdot_Edd (>~2E37 erg/s) is associated with a transition in the persistent spectral state and (as has been suggested previously) may be related to the increasing role of steady He-burning. We found examples of bursts separated by <30 min, including burst triplets and even quadruplets. We describe the oscillation amplitudes for 13 of the 16 burst oscillation sources, as well as the stages and properties of the bursts in which the oscillations are detected. The burst properties are correlated with the burst oscillation frequency; sources at <400 Hz generally have consistently short bursts, while the more rapidly-spinning systems have both long and short bursts. This correlation suggests either that shear-mediated mixing dominates the burst properties, or that the nature of the mass donor (and hence the evolutionary history) has an influence on the long-term spin evolution.Comment: 70 pages (emulateapj format), 22 figures, 11 tables, accepted by ApJS. The burst sample has been expanded with data made public since the previous submission; the discussion has been revised and substantially expanded following the referee team's report. Data tables will be available online in the usual places or from http://tinyurl.com/5rrg7

Adoption of an “Open” Envelope Conformation Facilitating CD4 Binding and Structural Remodeling Precedes Coreceptor Switch in R5 SHIV-Infected Macaques

A change in coreceptor preference from CCR5 to CXCR4 towards the end stage disease in some HIV-1 infected individuals has been well documented, but the reasons and mechanisms for this tropism switch remain elusive. It has been suggested that envelope structural constraints in accommodating amino acid changes required for CXCR4 usage is an obstacle to tropism switch, limiting the rate and pathways available for HIV-1 coreceptor switching. The present study was initiated in two R5 SHIVSF162P3N-infected rapid progressor macaques with coreceptor switch to test the hypothesis that an early step in the evolution of tropism switch is the adoption of a less constrained and more “open” envelope conformation for better CD4 usage, allowing greater structural flexibility to accommodate further mutational changes that confer CXCR4 utilization. We show that, prior to the time of coreceptor switch, R5 viruses in both macaques evolved to become increasingly sCD4-sensitive, suggestive of enhanced exposure of the CD4 binding site and an “open” envelope conformation, and this correlated with better gp120 binding to CD4 and with more efficient infection of CD4low cells such as primary macrophages. Moreover, significant changes in neutralization sensitivity to agents and antibodies directed against functional domains of gp120 and gp41 were seen for R5 viruses close to the time of X4 emergence, consistent with global changes in envelope configuration and structural plasticity. These observations in a simian model of R5-to-X4 evolution provide a mechanistic basis for the HIV-1 coreceptor switch

Perception of inappropriate cardiopulmonary resuscitation by clinicians working in emergency departments and ambulance services : The REAPPROPRIATE international, multi-centre, cross sectional survey

Introduction: Cardiopulmonary resuscitation (CPR) is often started irrespective of comorbidity or cause of arrest. We aimed to determine the prevalence of perception of inappropriate CPR of the last cardiac arrest encountered by clinicians working in emergency departments and out-of-hospital, factors associated with perception, and its relation to patient outcome. Methods: A cross-sectional survey was conducted in 288 centres in 24 countries. Factors associated with perception of CPR and outcome were analyzed by Cochran-Mantel-Haenszel tests and conditional logistic models. Results: Of the 4018 participating clinicians, 3150 (78.4%) perceived their last CPR attempt as appropriate, 548 (13.6%) were uncertain about its appropriateness and 320 (8.0%) perceived inappropriateness; survival to hospital discharge was 370/2412 (15.3%), 8/481 (1.7%) and 8/294 (2.7%) respectively. After adjusting for country, team and clinician's characteristics, the prevalence of perception of inappropriate CPR was higher for a non-shockable initial rhythm (OR 3.76 [2.13-6.64]; P 79 years) and in case of a "poor" first physical impression of the patient (3.45 [2.36-5.05]; P 79 years) and a "poor" first physical impression (0.26 [0.19-0.35]; P <0.0001). Conclusions: The perception of inappropriate CPR increased when objective indicators of poor prognosis were present and was associated with a low survival to hospital discharge. Factoring clinical judgment into the decision to (not) attempt CPR may reduce harm inflicted by excessive resuscitation attempts.Peer reviewe