Association of cardiac biomarkers with cardiovascular outcomes in patients with psoriatic arthritis and psoriasis: a longitudinal cohort study

Objective: In patients with psoriatic disease (PsD), we determined whether cardiac troponin I (cTnI) and N-terminal pro-brain-type natriuretic peptide (NT-proBNP) were associated with carotid plaque burden and the development of cardiovascular (CV) events independent of the Framingham Risk Score (FRS). Methods: Among 1,000 patients with PsD, carotid total plaque area (TPA) was measured in 358 participants at baseline. cTnI and NT-proBNP were measured using automated clinical assays. The association between cardiac biomarkers and carotid atherosclerosis was assessed by multivariable regression after adjusting for CV risk factors. Improvement in the prediction of CV events beyond the FRS was tested using measures of risk discrimination and reclassification. Results: In univariate analyses, cTnI (β coefficient 0.52 [95% CI 0.3, 0.74], p<0.001) and NT-proBNP (β coefficient 0.24 [95% CI 0.1, 0.39], p<0.001) were associated with TPA. After adjusting for CV risk factors, the association remained statistically significant for cTnI (adjusted β coefficient 0.21 [95% CI 0, 0.41], p=0.047), but not NT-proBNP (p=0.21). Among 1,000 patients with PsD assessed for CV risk prediction, 64 patients had incident CV events. When comparing a base model (with the FRS alone) to expanded models (with the FRS plus cardiac biomarkers), there was no improvement in predictive performance. Conclusion: In patients with PsD, cTnI may reflect the burden of atherosclerosis, independent of traditional CV risk factors. cTnI and NT-proBNP are associated with incident CV events independent of the FRS, however, further study of their role in CV risk stratification is warranted

Targeted metabolomic profiling and prediction of cardiovascular events: a prospective study of patients with psoriatic arthritis and psoriasis

Objective: In patients with psoriatic disease (PsD), we sought serum metabolites associated with cardiovascular (CV) events and investigated whether they could improve CV risk prediction beyond traditional risk factors and the Framingham Risk Score (FRS). Methods: Nuclear magnetic resonance metabolomics identified biomarkers for incident CV events in patients with PsD. The association of each metabolite with incident CV events was analysed using Cox proportional hazards regression models first adjusted for age and sex, and subsequently for traditional CV risk factors. Variable selection was performed using penalisation with boosting after adjusting for age and sex, and the FRS. Results: Among 977 patients with PsD, 70 patients had incident CV events. In Cox regression models adjusted for CV risk factors, alanine, tyrosine, degree of unsaturation of fatty acids and high-density lipoprotein particles were associated with decreased CV risk. Glycoprotein acetyls, apolipoprotein B and cholesterol remnants were associated with increased CV risk. The age-adjusted and sex-adjusted expanded model with 13 metabolites significantly improved prediction of CV events beyond the model with age and sex alone, with an area under the receiver operator characteristic curve (AUC) of 79.9 versus 72.6, respectively (p=0.02). Compared with the FRS alone (AUC=73.9), the FRS-adjusted expanded model with 11 metabolites (AUC=75.0, p=0.72) did not improve CV risk discrimination. Conclusions: We identify novel metabolites associated with the development of CV events in patients with PsD. Further study of their underlying causal role may clarify important pathways leading to CV events in this population

Use of a Bacteriophage Lysin to Identify a Novel Target for Antimicrobial Development

<div><p>We identified an essential cell wall biosynthetic enzyme in <i>Bacillus anthracis</i> and an inhibitor thereof to which the organism did not spontaneously evolve measurable resistance. This work is based on the exquisite binding specificity of bacteriophage-encoded cell wall-hydrolytic lysins, which have evolved to recognize critical receptors within the bacterial cell wall. Focusing on the <i>B. anthracis</i>-specific PlyG lysin, we first identified its unique cell wall receptor and cognate biosynthetic pathway. Within this pathway, one biosynthetic enzyme, 2-epimerase, was required for both PlyG receptor expression and bacterial growth. The 2-epimerase was used to design a small-molecule inhibitor, epimerox. Epimerox prevented growth of several Gram-positive pathogens and rescued mice challenged with lethal doses of <i>B. anthracis</i>. Importantly, resistance to epimerox was not detected (<10⁻¹¹ frequency) in <i>B. anthracis</i> and <i>S. aureus</i>. These results describe the use of phage lysins to identify promising lead molecules with reduced resistance potential for antimicrobial development.</p> </div

Identification and analysis of 2-epimerase in <i>B. anthracis</i>.

<p>(A) <i>sps</i> loci of the <i>B. cereus</i> lineage. Islands of variable <i>sps</i> genes are connected by gray regions and denoted by different colors. Conserved flanking sequences are shown. Red shaded loci (not in Ames) are cell wall-biosynthetic genes similar to that encoded by Ames. Inverted arrows are repeat elements. Susceptibility to PlyG lysis and GFP-PlyG^BD surface binding are shown. For PlyG lysis, the “+++” designation is based on an assay <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0060754#pone.0060754-Schuch1" target="_blank">[8]</a> for zones of complete bacteriolysis on agar plates overlaid with the indicated organism and treated with a 10 µl drop of PBS containing 1 µg of PlyG; “++” indicates a slight reduction in activity compared to complete bacteriolysis, and “-“ indicates an absence of bacteriolysis. For PlyG^BD binding, designations are based on exposure times needed to clearly visualize binding of GFP-PlyG^BD to target organisms by fluorescence microscopy; “+++” indicates a <5 second exposure, “+” indicates a 15–30 second exposure, and “-“ indicates no fluorescence is observed. Abbreviations: w/c, whole-cell binding; p/s, polar/septal binding. (B) Genetic representation of 2-epimerase double mutant, RS1205. (C) Growth of RS1205 (with indicated IPTG concentrations) compared to the parental wild-type strain ΔSterne. Mean averages are shown (n = 3) with standard deviations. (D) Morphological analysis of RS1205 after five hours of growth without IPTG. Phase contrast images and corresponding fluorescence fields are shown for GFP-PlyG^BD-labeled RS1205 (5 second exposure) and <i>B. anthracis</i> ΔSterne (30 second exposure). For Deltavision images, NPS (red) was labeled with rhodamine-PlyG^BD, division septa (green) were labeled with vancomycin BODIPY FL, and DNA (blue) was labeled with DAPI. TEM images are shown with scale bars (500 nm) and arrows denote some division septa. (E) Phase contrast microscopic images of RS1205 grown for 12 hours with and without IPTG (5 µM).</p

Antimicrobial activity of epimerox.

<p>(A) Chemical structure of epimerox. (B) Growth curves of <i>B. anthracis</i> ΔSterne in BHI medium with and without epimerox. (C) Morphologies of <i>B. anthracis</i> and <i>S. aureus</i> after 5 hours of exposure to epimerox (5 µM and 14 µM, respectively). For Deltavision images, NPS (red) was labeled with rhodamine-PlyG^BD, division septa (green) were labeled with vancomycin BODIPY FL, and DNA (blue) was labeled with DAPI. For TEM images, arrows indicate some division septa. Scale bars are shown. (D) Growth inhibition assays for Gram-positive and -negative organisms. Cultures were grown in BHI medium with and without indicated epimerox concentrations for 11 hours at 28°C. (E) Growth curves of <i>S. aureus</i> strain RN4220 in BHI medium with and without epimerox. (F) Survival plot of C57BL/6 mice after i.p. infection with 5×10⁵ CFUs of <i>B. anthracis</i> Sterne, and i.p. treatment with buffer starting at 3 hours post-infection (and continuing every 6 hours for 7 days), or epimerox (13 mg/kg) starting at 3 hours or 24 hours post-infection (and continuing every 6 hours for 7 days).</p

Interaction of PlyG with <i>B. anthracis</i> NPS.

<p>(A) Dose-dependent inhibition of PlyG lytic activity after pre-incubation with <i>B. anthracis</i> NPS. (B) PlyG activity after pre-incubation with increasing amounts of the CWG from <i>Streptococcus pyogenes</i>. (C) Dose-dependent inhibition of PlyG^BD surface-binding after pre-incubation with <i>B. anthracis</i> NPS. (D) Deltavision images of surface-labeled <i>B. anthracis</i> with or without proteinase K treatment (+/−PK). NPS (green) was labeled with GFP-PlyG^BD, and the S-layer Sap protein (red) was labeled with specific antibodies and an Alexa Fluor 647-conjugated secondary antibody. (E) Dot-blot analysis of PlyG^BD binding to total cell wall material and both SDS-treated and HF-treated walls.</p