Platelet extracellular vesicles are superior to cardiac troponin to diagnose acute coronary syndrome with short symptom duration: LEMONADE trial

Background

Acute coronary syndrome (ACS), which comprises acute myocardial infarction (AMI) and unstable angina pectoris (UAP), is one of the main causes of mortality worldwide. Cardiac troponin is the gold standard to diagnose AMI. Troponin has two main disadvantages: it is negative in patients with UAP but positive in other diseases. During ACS, activated platelets release extracellular vesicles (EVs), which promote coagulation and associate with fibrin, and contribute to thrombus formation. We hypothesized that the concentration and composition of circulating platelet EVs (1) change in blood of patients with ACS compared to patients with other causes of chest pain, and (2) thereby allow earlier diagnosis of ACS than cardiac troponin.

Purpose

We aimed to determine the diagnostic value of circulating platelet EVs as novel early biomarkers of developing ACS.

Methods

We conducted a prospective, multicentre trial enrolling 105 patients who presented to the emergency department with suspected ACS. Blood was collected at admission to measure the concentration of EVs and cardiac troponin. Flow cytometry (Apogee A60-Micro) was used to determine plasma concentrations of platelet EVs exposing P-selectin (CD61+/CD62p+) and fibrin (CD61+/fibrin+).

Results

Plasma concentrations of platelet EVs exposing fibrin was lower in patients with ACS, compared to patients with other causes of chest pain (p=0.023) and lower in patients with an occlusive thrombus compared to non-occlusive plaque (p=0.015). Fibrin exposing-EVs were independent predictors of ACS (OR 8.2, CI 1.3–16.4) in multivariate analysis, allowing to diagnose ACS with 75% sensitivity and 72% specificity. Among patients with pain onset less than 2 hours before presentation, fibrin-exposing EVs had substantially better diagnostic performance than troponin (area under the ROC curve 0.90 vs. 0.74, respectively). Regarding other causes of chest pain, fibrin-exposing EVs were the lowest in patients with ACS, higher in patients with other cardiological causes of chest pain, and the highest in patients with non-cardiological causes of chest pain (p=0.036).

Conclusions

Circulating fibrin-exposing EVs are early biomarkers of developing ACS, superior to cardiac troponin in patients with pain onset less than 2 hours before presentation. Incorporation of EV measurements into the ACS diagnostic algorithm might revolutionise thrombotic risk stratification in the emergency setting.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Specialised Research Fellowship, “Club 30” of the Polish Society of Cardiology

Safety and effectiveness of very high-power short duration ablation in patients with atrial fibrillation: early results

Background

Pulmonary vein isolation (PVI) is at the forefront of treatment methods of rhythm control in patients with atrial fibrillation (AF) (1). The novel contact-force sensing catheter, QDot MicroTM (Biosense Webster) was designed to improve effectiveness of AF ablation and allow better time management due to shorter procedure time. It is a very high power-short duration (vHP-SD) catheter optimized for high density mapping and temperature control, which enables the application of high energy (up to 90W, 4s) (2).

Purpose

The aim of the study was to compare the QDot MicroTM catheter with the ThermoCool SmarttouchTM SF catheter with regard to the effectiveness and safety of PVI ablation.

Methods

It is a single center, cross-sectional, observational study enrolling 101 consecutive patients suffering from symptomatic paroxysmal or persistent AF, referred for first catheter ablation between 16 December 2019 and 03 December 2021. In 47 procedures (mean age 54 years; 70% male; 77% paroxysmal) the QDot Micro catheter was used (vHP-SD group; Qmode+ 90W, 4s), whereas the remaining 54 patients (mean age 57 years; 70% male; 67% paroxysmal) were treated with the ThermoCool SmarttouchTM SF catheter (control group, Ablation Index guided ablation). The primary endpoint was freedom from AF at 3-months after ablation. The secondary endpoints included the amount of opioids administered as well as the incidence of early-onset treatment-emergent adverse events (TEAEs).

Results

AF recurrence was documented in 14.9% patients in vHP-SD group and in 31.5% patients in control group (p=0.06). The mean dose of remifentanil was reported to be lower during Qmode+ catheter-based PVI (0.50 (0.40–0.60) vs. 0.70 (0.55–0.90) mg; p<0.001). There was no statistically significant difference in TEAEs between both groups (6.3 vs. 0%; p=0.10). One severe adverse event (cerebral vascular incident 2 days after PVI – due to thrombus in the left ventricle) was observed in vHP-SD group.

Conclusions

This study suggests that the vHP-SD ablation is safe and enables sedative-analgesic medications demand reduction during procedure. vHP-SD mode may enhance the success rate of catheter-based PVI, however further research is needed to provide additional evidence of its superiority.

Funding Acknowledgement

Type of funding sources: None.

Leukocyte extracellular vesicles as the first biomarkers to predict outcomes in patients undergoing percutaneous aortic valve replacement

Background

Transcatheter aortic valve implantation (TAVI) is a novel treatment for aortic stenosis (AS), associated with better outcomes than surgical aortic valve replacement in high-risk patients. However, up to 29% of patients annually experience major adverse cardiac and cerebrovascular events (MACCE) after TAVI. MACCE are mostly caused by atherothrombosis, i.e. formation of platelet aggregates (thrombi) on ruptured atherosclerotic plaques. Because platelets release extracellular vesicles (EVs) during thrombus formation, we hypothesized that EVs are a biomarker to predict MACCE after TAVI.

Methods

This was a multicentre, prospective clinical study. Venous blood was collected 1 day before TAVI and at hospital discharge (n=57, mean age 79.9+6.4 years, 49% male). Flow cytometry (Apogee A60-Micro) was used to determine concentrations of plasma EVs labelled with markers for endothelial cells (CD146), leukocytes (CD45), platelets and megakaryocytes (CD61) and activated platelets (CD62p). Analysis of flow cytometry data files was fully automated. Rosetta Calibration (Exometry) and Flow-SR were used for diameter and refractive index determination. Wilcoxon signed rank test was used to compare EV concentrations before and after TAVI. The predictive value of EVs for MACCE and the cut-offs were calculated using a receiver operating characteristic curve. Logistic regression model incorporating EV concentrations and clinical characteristics was used to determine the best model for MACCE prediction.

Results

Concentrations of EVs from activated platelets increased, whereas from leukocytes decreased after TAVI, compared to the measurement before (p=0.06, p=0.04, respectively). Among 55 patients discharged from the hospital, 14 patients experienced MACCE (25%) during the median 15 months of observation. Increased baseline concentration of leukocyte EVs and male gender were the only independent predictors of MACCE in multivariable analysis (OR 4.01, 95% CI 0.77–23.77, p=0.04 for leukocyte EVs; OR 6.84, 95% CI 1.41–33.17, p=0.03 for male gender).

Conclusions

We identified increased concentrations of leukocyte EVs as new candidate biomarkers to predict MACCE after TAVI. Leukocyte EVs could be used to augment risk stratification in this patient cohort. The next step is to validate the clinical applicability of EVs to predict post-TAVI MACCE in a large-scale clinical trial.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Young Investigator Grant of the Polish Society of Cardiology

Left atrial thrombus in atrial fibrillation/flutter patients in relation to anticoagulation strategy: LATTEE registry

Funding Acknowledgements

Type of funding sources: None.

Background

Atrial fibrillation (AF) and flutter (AFl) increase the risk of thromboembolism by promoting clot formation in the left atrium. Current guidelines recommend initiation of oral anticoagulation (OAC) with vitamin K antagonists (VKAs) or, preferably, non-VKA-OACs (NOACs) in men and women with a CHA2DS2VASc score of ≥2 and ≥3, respectively. Effective OAC is also recommended 3 weeks before elective AF cardioversion or catheter ablation with pre-procedural ttransesophageal echocardiography (TEE) as an alternative. However, TEE before AF/AFl cardioversion or ablation is often performed even in anticoagulated patients, given that, in clinical practice, "effective" OAC may be difficult to achieve and/or verify.

Purpose

The aim of the study was to assess the prevalence of left atrial thrombus (LAT) in AF/AFl in relation to OAC strategy.

Methods

The Left Atrial Thrombus on Transesophageal Echocardiography (LATTEE) registry was a prospective, observational study enrolling consecutive patients with AF or AFl in whom TEE was performed before direct current cardioversion or catheter ablation, hospitalized in 13 cardiology departments in Poland. Patients’ recruitment process started from November 2018 in the coordinating centre and lasted 12 months since the beginning of the study in each participating centre or longer, i.e., until the inclusion of at least 200 patients at each participating centre (with the last patient enrolled in May 2020).

Results

Of 3109 patients enrolled, 88% were on chronic, 1.5% on transient OAC and 10% without OAC. Of patients on chronic OAC, 39% received rivaroxaban, 30% dabigatran, 14% apixaban and 18% vitamin K antagonists (VKA). Patients on apixaban were oldest, had worst renal function and highest both bleeding and thromboembolic risk, and more often received reduced doses. Overall, prevalence of LAT was 8.0% (7.3% on chronic OAC vs. 15% without OAC; p<0.01). In patients on VKA, prevalence of LAT was doubled compared to patients on non-VKA-OACs (NOACs) (13% vs. 6.0%; p<0.01), even after propensity score matching (13% vs. 7.5%; p<0.01) and in multivariable logistic regression (OR 1.9, 95% confidence interval 1.4-2.8). Prevalence of LAT in patients on apixaban was higher (9.8%) than in those on rivaroxaban (5.7%) and dabigatran (4.7%; p<0.01 for both comparisons). However, in propensity score matching and multivariable logistic regression, there was no difference in the risk of LAT between apixaban and other NOACs.

Conclusions

Prevalence of LAT in AF is non-negligible even on chronic OAC. In the real-world AF/AFl population, the risk of LAT seems higher on VKA compared to NOAC, and similar between different NOACs.

Stress echocardiography in patients with ischemic mitral regurgitation and left ventricular dysfunction qualified to cardiosurgery treatment

Funding Acknowledgements

Type of funding sources: None.

Introduction

Ischemic mitral regurgitation (IMR) is predominantly related to left ventricle (LV) remodeling and mitral valve deformation. Although coronary artery bypass grafting alone (CABGa) or with mitral annuloplasty (CABGmp) is considered the best therapeutic strategies for patients with IMR, some recurrences are still reported.

Purpose

The aim of this study was to evaluate use of the mitral deformation indices (MDI) as a predictor of recurrence of IMR in 1-year follow-up after surgery.

Methods

A total of 145 patients after myocardial infarction with significant IMR, eligible for CABG, were prospectively enrolled in the study. Patients were referred for CABGa (gr.1; n = 90) or CABGmp (gr.2; n = 55), based on clinical assessment and the results of rest and stress echocardiography. One year after surgery each patient underwent the evaluation of cardiovascular events. Univariable logistic regression analysis was used to identify factors of recurrence of IMR in 1 year follow-up.

Results

Logistic regression analysis revealed that in CABGa group preoperative changes of TA and CH during DBX remained the predictors of the recurrence of IMR in 12 months follow-up. TAdbx > 1 cm2 provided sensitivity of 90% and specificity of 29%, (AUC 0.6436); The best cut-off value for CHdbx was 0.4 cm (sensitivity 90%, specificity 34%; AUC 0.6432). In both groups no significant differences were observed in 12-month mortality (1.2% vs 0%; p = 1.0), hospitalizations due to the heart failure (HF) exacerbation (5.9% vs 8.5%; p = 0.72) and in the incidence of the composite endpoint (deaths/CV hosp/stroke) (7% vs 8.5%; p = 0.742).

Conclusion

Preoperative assessment of MDI changes during dbx can be used to identify patients with IMR at increased risk of recurrence of significant IMR in 1 year follow-up. Abstract Figure 1  Abstract Figure 2

Right ventricular dysfunction in patients with non-severe ischemic mitral regurgitation qualified to cardiosurgery treatment

Funding Acknowledgements

Type of funding sources: None.

Introduction

Right ventricular (RV) dysfunction worsens prognosis in patients (pts) after myocardial infarction (MI).

Purpose

The purpose of this study was to assess RV function as a predictor of mortality and hospitalizations due to exacerbation of HF in pts with ischemic mitral regurgitation (IMR) qualified for cardiosurgical treatment - coronary artery by-pass grafting alone (CABGa) or CABG with mitral reconstruction (CABGmr).

Methods

We prospectively analyzed 104 pts (M 57, 64 ± 7 years) with non-severe IMR, 3-24 weeks after MI. Effective regurgitation orifice (ERO) was used for quantitative IMR assessment (non-severe ≥10-20 mm²). All the pts were qualified for CABG (multiple vessel coronary disease, ejection fraction (EF)-44 ± 8%). The patients were referred for CABGa (gr.1; n = 77) or CABGmr (gr.2; n = 27) based on clinical assessment, 2D and 3D echo at rest and exercise. Tricuspid annular plane systolic excursion (TAPSE) was acquired to evaluate RV function (measured with M-mode imaging in the 4-chamber view). RV function was related to clinical outcome (median follow-up: 12 months).

Results

During the follow-up period of 12 months, 5 deaths (5 %) and 8 hospitalizations (8%) due to exacerbation of HF occurred. With use of the following cut-off points of TAPSE ≤ 12 mm (group I), and TAPSE >12 mm (group 2)—an association was found between the lower TAPSE and increased mortality. In group 1 (n =54 pts), 5 pts (9.2%) died and 6 pts was hospitalized due to HF (11.1%); in group 2 (n =50), no patient died, and 2 pts was hospitalized (4%). There was a significant difference (p = 0.02) in clinical outcomes between group I and II. ROC analysis identified TAPSE ≤12 mm as predictive cut-off for prediction adverse clinical outcome in all study group: (death: sensitivity 80%, specificity 76%, area under curve [AUC] = 0.807 (Fig.1); death and HF hospitalizations: sensitivity 69%, specificity 79%; AUC =0.767).

Conclusion

TAPSE is simple and useful quantitative measurement of RV function and have a predictive value in pts with non-severe IMR referred for cardiosurgery treatment. Abstract Figure 1

Right ventricle dysfunction in patients with takotsubo syndrome

Funding Acknowledgements

Type of funding sources: None.

OnBehalf

Pol-tako

Background 

Takotsubo syndrome  (TTS) is a clinical condition that mimics acute myocardial infarction and is characterised by acute left ventricle dysfunction. However, right ventricle (RV) involvement can also occur. 

Purpose  

The aim of our study was to compare clinical characteristic, in-hospital complications and in-hospital mortality in patients with TTS with and without RV dysfunction. 

Methods  

209 consecutive patients with TTS were included in the study. Among them, 13,9% (29 patients) had RV dysfunction according to echocardiography evaluation. Clinical symptoms at admission to hospital was similar in both groups. There weren’t differences in time from onset of symptoms to the hospital admission in both groups. 

Results  

Patients with RV dysfunction was older (75,6 vs 69.4y). Left ventricle ejection fraction (LVEF) at 1st and 3rd day of hospitalisation was lower in patients with TTS with RV involvement in comparison to patients without RV dysfunction (37.9 vs 41.9%, 42,1 vs 47.3% and 46.1 vs 50.9%, respectively). However, at 5th day EF LV was similar in both groups. Tricuspid annular plane systolic excursion (TAPSE) was lower in patients with RV dysfunction at 1st and 3rd day (17 vs 21mm and 19 vs 21.6 mm, respectively). Pulmonary oedema and cardiogenic shock occurred less often in patients with RV involvement (6.9 vs 17.7% and 0 vs 4.4%). In hospital mortality was similar in both groups (3.4 and 2.2%).  Moreover, there was not difference in the length of hospitalisation (11.9 vs 10.1 days). 

Conclusions 

Right ventricle in patients with TTS can occur in about 14% patients. In addition to impaired RV function also LVEF is more depressed in the first days. However, in hospital mortality is similar.

Sex differences in patients with takotsubo syndrome

Funding Acknowledgements

Type of funding sources: None.

OnBehalf

Pol-tako

Introduction 

Takotsubo syndrome (TTS) is an acute revesible left ventricular dysfunction which occurs mainly in postmenopausal women. Despite the fact that the most patients with TTS are postmenopausal women and the possible patomechanism is related to female hormones, including estrogens, men also suffer from TTS. 

Objectives 

The goal of this study was to compare course of disease and prognoses in male and female patients with TTS. 

Patients and Methods 

The analysis included 210 patients (192 women and 18 men) hospitalized at the academic hospital from the year 2006 to 2020. 

Results 

Physical stress was trigger of TTS more often in men than women (50 vs. 38%). There were no differences in the frequency of risk factors and comorbidities, with the exception of higher prevalence of smoking in men. Markers of cardiac necrosis were similar in both groups.  At admission and peak NTproBNP levels were significantly more elevated in women (1527 vs. 3152 and 3752 vs. 5079pg/ml, respectively).  ST depression was found more frequently in men than in women (22 vs. 5%). Ejection fraction was lower among male patients at discharge (50 vs. 60%), despite the same length of hospitalization. Beta-adrenolytics and statins were more frequently prescribed for women than for men (90 vs 78% and 68 vs. 31%) whereas ACEI was prescribed in 96% men and 79% women. Moreover, there was P2Y12 inhibitors were more often used in men (33 vs 10.4%). In-hospital complications (arrhytmias, mechanical complications, cardiogenic shock) were similar in both groups. However, mortality rate was higher in women (3 vs. 0%).  

Conclusions 

Clinical course in patients with TTS is similar in women and men. However, in-hospital mortality was higher in women.

Double superior vena cava and left brachiocephalic vein agenesis: a rare systemic vein anomaly and potential source of cardiac implantable electronic device and central venous catheter placement complications

Abnormal systemic vein development produces anomalous veins, which - in the case of persistent left superior vena cava and/or left brachiocephalic vein - exhibit considerable topographic and morphometric differences in comparison with their usual anatomy. The nature and extent of those developmental anomalies - detected during intravenous procedures, such as cardiac implantable electronic device (CIED) lead insertion or central venous catheter placement - may hinder the procedure itself and/or adversely affect its outcome, both at the stage of cardiac lead advancement through an abnormally shaped vessel and lead positioning within the heart. This may lead to problems in achieving optimal sensing and pacing parameters and in ensuring that the patient cannot feel the pacing impulses. These events accompanied a de novo CIED implantation procedure in the patient with a double superior vena cava and left brachiocephalic vein agenesis, who ultimately required reoperation.

Rapid response to emerging biomedical challenges and threats

As part of the global mobilization to combat the present pandemic, almost 100 000 COVID-19-related papers have been published and nearly a thousand models of macromolecules encoded by SARS-CoV-2 have been deposited in the Protein Data Bank within less than a year. The avalanche of new structural data has given rise to multiple resources dedicated to assessing the correctness and quality of structural data and models. Here, an approach to evaluate the massive amounts of such data using the resource https://covid19.bioreproducibility.org is described, which offers a template that could be used in large-scale initiatives undertaken in response to future biomedical crises. Broader use of the described methodology could considerably curtail information noise and significantly improve the reproducibility of biomedical research.

Synchrotron Radiation as a Tool for Macromolecular X-Ray Crystallography: a XXI Century Perspective

Intense X-rays available at powerful synchrotron beamlines provide macromolecular crystallographers with an incomparable tool for investigating biological phenomena on an atomic scale. The resulting insights into the mechanism's underlying biological processes have played an essential role and shaped biomedical sciences during the last 30 years, considered the "golden age" of structural biology. In this review, we analyze selected aspects of the impact of synchrotron radiation on structural biology. Synchrotron beamlines have been used to determine over 70% of all macromolecular structures deposited into the Protein Data Bank (PDB). These structures were deposited by over 13,000 different research groups. Interestingly, despite the impressive advances in synchrotron technologies, the median resolution of macromolecular structures determined using synchrotrons has remained constant throughout the last 30 years, at about 2 Å. Similarly, the median times from the data collection to the deposition and release have not changed significantly. We describe challenges to reproducibility related to recording all relevant data and metadata during the synchrotron experiments, including diffraction images. Finally, we discuss some of the recent opinions suggesting a diminishing importance of X-ray crystallography due to impressive advances in Cryo-EM and theoretical modeling. We believe that synchrotrons of the future will increasingly evolve towards a life science center model, where X-ray crystallography, Cryo-EM, and other experimental and computational resources and knowledge are encompassed within a versatile research facility. The recent response of crystallographers to the COVID-19 pandemic suggests that X-ray crystallography conducted at synchrotron beamlines will continue to play an essential role in structural biology and drug discovery for years to come.

Covid-19.bioreproducibility.org: A web resource for SARS-CoV-2-related structural models

The COVID-19 pandemic has triggered numerous scientific activities aimed at understanding the SARS-CoV-2 virus and ultimately developing treatments. Structural biologists have already determined hundreds of experimental X-ray, cryo-EM, and NMR structures of proteins and nucleic acids related to this coronavirus, and this number is still growing. To help biomedical researchers, who may not necessarily be experts in structural biology, navigate through the flood of structural models, we have created an online resource, covid19.bioreproducibility.org, that aggregates expert-verified information about SARS-CoV-2-related macromolecular models. In this article, we describe this web resource along with the suite of tools and methodologies used for assessing the structures presented therein.

Clinical characteristics and risk profile of patients with atrial fibrillation with mid-range ejection fraction, insights from the Polish part of EORP-AF Long-Term General Registry

Background

Atrial fibrillation (AF) comprises a wide range of patients (pts), from those with preserved to those with reduced left ventricular ejection fraction (LVEF). According to 2016 ESC guidelines, pts with LVEF in the range of 40–49% represent a “grey area”, which is defined as heart failure with mid-range ejection fraction (HFmrEF). Not much is known about the clinical characteristics of AF pts with mid-range ejection fraction.

Purpose

To determine the potential differences in the clinical characteristics, risk profile, and the outcomes of AF with moderate systolic dysfunction, measured by LVEF.

Methods

The EURObservational Research Programme on AF (EORP-AF) Long-Term General Registry analyzed consecutive AF patients who have presented to cardiologists in 250 centers from 27 European countries, including 25 centers from Poland. We analyzed data collected at baseline and at a 1-year follow-up visit from 568 Polish patients included in 25 Polish centers in the years 2013–2016. Pts were divided into three groups based on LVEF: the preserved LVEF (pEF) group (LVEF ≥50%), the mid-range LVEF (mrEF) group (40–49%), and the reduced LVEF (rEF) group (<40%).

Results

117/568 pts with rEF represented 20,6%, 105/568 mrEF 18,5% and 346/568 pEF 60,9% of the whole analyzed group. With regard to the most typical risk factors, the mrEF population appeared between rEF and pEF, presenting a moderate risk profile with the exception of hypertension, which was the most common in the mrEF group. While permanent AF was the most common in the rEF group and paroxysmal in the pEF pts, pts with mrEF had a higher rate of long-lasting persistent AF. Taking into account the risk factors profile, surprisingly, pts with AF and mrEF more often presented with dyspnea/shortnes of breath (mrEF 38,1% vs. rEF 18,8% vs. pEF 22,5%; p=0,001) and fatigue (mrEF 38,1% vs. rEF 23,9% vs. pEF 25,4%; p=0,025). AF pts with mrEF also had the highest thrombo-embolic risk estimated with the CHA2DS2-VASc score (mrEF 4 [2–5], n=105; rEF 3 [2–5], n=117, pEF 3 [2–4], n=346, p=0.005). However, this did not translate into the highest number of thromboembolic events after one year which did not significantly differ (mrEF 10.5%, rEF 15.4%, pEF 11.3%, p=0.30) between the three groups.

Conclusions

The risk factor profile of AF pts with mrEF was milder than for those with rEF and more severe than for pEF pts. AF pts with mrEF more often presented HF symptoms. Their estimated thrombo-embolic risk was higher but the number of events in the one year follow-up did not significantly differ between groups.

Funding Acknowledgement

Type of funding source: None

Molecular determinants of vascular transport of dexamethasone in COVID-19 therapy

Dexamethasone, a widely used corticosteroid, has recently been reported as the first drug to increase the survival chances of patients with severe COVID-19. Therapeutic agents, including dexamethasone, are mostly transported through the body by binding to serum albumin. Here, the first structure of serum albumin in complex with dexamethasone is reported. Dexamethasone binds to drug site 7, which is also the binding site for commonly used nonsteroidal anti-inflammatory drugs and testosterone, suggesting potentially problematic binding competition. This study bridges structural findings with an analysis of publicly available clinical data from Wuhan and suggests that an adjustment of the dexamethasone regimen should be further investigated as a strategy for patients affected by two major COVID-19 risk factors: low albumin levels and diabetes.

Molecular determinants of vascular transport of dexamethasone in COVID-19 therapy

Dexamethasone, a widely used corticosteroid, has recently been reported as the first drug to increase the survival chances of patients with severe COVID-19. Therapeutic agents, including dexamethasone, are mostly transported through the body by binding to serum albumin. Herein, we report the first structure of serum albumin in complex with dexamethasone. We show that it binds to Drug Site 7, which is also the binding site for commonly used nonsteroidal anti-inflammatory drugs and testosterone, suggesting potentially problematic binding competition. This study bridges structural findings with our analysis of publicly available clinical data from Wuhan and suggests that an adjustment of dexamethasone regimen should be considered for patients affected by two major COVID-19 risk-factors: low albumin levels and diabetes.

P1384Radiation safety and electrophysiologists: radiation protection status

INTRODUCTION

 Ionizing radiation is typically used during variety electrophysiological (EP) procedures, although it may contribute to deterministic effects especially for staff. 

PURPOSE

 The purpose of this study was to perform an analysis of EP operators’ radiation protective devices for occupational exposure. 

METHODS

 Data reported herein were gathered from international, multi-site, prospective, Go 4 Zero Fluoroscopy registry. The registry encompassed 25 European EP centers, and up to 5 operators from each center. The presence of operators’ X-ray protection tools was examined to determine the level of operators’ protection. Additionally, the tests included availability of measures to decrease radiation output and exposure control measures. Finally, the analysis of correlation between the X-ray protection and degree of operators’ experience (<5, 5-15,>15 years) as well as number of procedures performed per month (1-9, 10-19, 20-39, >40 procedures/month) was performed. 

RESULTS

 Our analysis included 95 operators (median age: 39 years, 85% of male, median training time: 5 years). The whole study group performed annually medical examinations due to radiation exposure and 56% of them received dosimetry reports once a month, 5% - once every 3 months, and 39% - once a year. Irrespectively of experience or number of performed procedures the most frequently used X-ray protection tools (used by >80% of group) were lead apron, thyroid shields, screen below the table, glass in the lab, and least often (used by < 6% of group) – protective gloves and cabin. The most often exposure control measures used were chest (95%) followed by collar (31%), ring (24%) and eye (7%) dosimeters. The inverse correlation between level of experience and measures to decrease radiation output was observed (collimation: 84%, 80% and 78%; minimizing the tube-to intensifier distance: 100%, 93% and 91% of operators with <5, 5-15 and >15 years of experience, respectively). There were not observed differences between type of radiation protection equipment and operators’ level of experience or number of procedures. Additionally, there were no differences between male and female operators regarding protective equipment, expect eyeglasses or cabin that were more often used by men. Operators who were protected by >4 X-ray protection tools were exposed for higher radiation levels as compared to those protected by <4 X-ray protection tools (median [IQR] radiation exposure: 0.6 [0.2-1.1] vs 0.2 [0.1-0.2] mSv per month, p < 0.0001; 1.1 [0.1-12.0] vs 0.5 [0.1-1.1] mSv per year, p < 0.0001). There were no differences between the type of (universitary vs non-universitary) or institution’s localization (Eastern vs Central vs Western Europe) and used protective equipment.  

CONCLUSIONS

 Both proper radiation protective equipment, and regular medical examination due to professional exposure are mandatory to reduce radiation exposure in practice.

P1573 Late recovery of left ventricular function in patients with non-severe ischemic mitral regurgitation and multivessel disease qualified to cardiosurgery treatment

Purpose

In patients (pts) after myocardial infarction (MI) with chronic left ventricle (LV) dysfunction, the presence and degree of ischemic mitral regurgitation (IMR) are predominantly related to LV remodelling and mitral valvular deformation. The aim of this study was to compare functional recovery (LVFR) as well as reverse remodelling of the left ventricle (LVRR) in pts with non-severe IMR qualified for cardiosurgical treatment - coronary artery bypass grafting alone (CABGa) or CABG with mitral repair (CABGmr in the 12-month follow-up.

Materials and methods

A total of 100 pts (mean age 64,4 ± 7,9 years) after MI, eligible for CABG, were included in a prospective study. Echo and clinical assessment were performed before and 12-months after surgery. Pts were referred for CABG a(gr.1; n = 74) or CABGmr (gr.2; n = 26) based on clinical assessment, 2D echo at rest and exercise and myocardial viability assessment (low dose dobutamine - dbx). Effective regurgitation orifice area (EROA) was used for quantitative IMR assessment. An increase in EF≥ 5% (ΔEF) from baseline value was considered as LVFR. A decrease in LV end-systolic volume > 15% from baseline value was considered as LVRR. Multivariable logistic regression analysis was used to identify the strongest factors of lack of LVFR and LVRR.

Results

An LVFR was observed, at late control, in 35 (49%) of pts in the CABGa group and in 11 (48%) of pts in CABGmr group (p = 0,948). LVRR was observed in 41 (56%) of pts in the CABGa group and in 16 (70%) of pts in CABGmr group 12 months follow-up (p = 0,5). In pts with LVFR, there was a lower incidence of at least moderate IMR at follow-up (ΔEF dbx≥5% vs ΔEFdbx < 5%:11% vs 30% pts; p = 0,05). Multivariable logistic regression analysis revealed that in both CABGa and CABGmr group only preoperative age and EF changes during stress echo remained the independent predictors of the lack of LVFR in 12 months follow-up (table 1).

Conclusions

1. LVFR and LVRR were reported in most of the pts in both analyzed groups.

2. Preoperative assessment of changes EF during dbx (ΔEFdbx)can be used to identify pts with IMR at increased risk of lack of improvement in LV function and risk of residual IMRin 12-month f-up after surgery.

Parameters Odds ratio (OR) Odds ratio (OR) p CABGa vs CABGmr 0,644 0,215 - 1,927 0,432 Age (increase by every 5 years) 1,11 1,039 - 1,879 0,003 ΔEF dbx (increase by every 5%) 0,21 0,096 - 0,46 <0,001 Table 1. Prognostic factors lack improvement in left ventricle function.

The Integrated Resource for Reproducibility in Macromolecular Crystallography: Experiences of the first four years

It has been increasingly recognized that preservation and public accessibility of primary experimental data are cornerstones necessary for the reproducibility of empirical sciences. In the field of molecular crystallography, many journals now recommend that authors of manuscripts presenting a new crystal structure should deposit their primary experimental data (X-ray diffraction images) to one of the dedicated resources created in recent years. Here, we describe our experiences developing the Integrated Resource for Reproducibility in Molecular Crystallography (IRRMC) and describe several examples of a crucial role that diffraction data can play in improving previously determined protein structures. In its first four years, several hundred crystallographers have deposited data from over 5200 diffraction experiments performed at over 60 different synchrotron beamlines or home sources all over the world. In addition to improving the resource and curating submitted data, we have been building a pipeline for extraction or, in some cases, reconstruction of the metadata necessary for seamless automated processing. Preliminary analysis indicates that about 95% of the archived data can be automatically reprocessed. A high rate of reprocessing success shows the feasibility of using the automated metadata extraction and automated processing as a validation step for the deposition of raw diffraction images. The IRRMC is guided by the Findable, Accessible, Interoperable, and Reusable data management principles.

Persistence of phylogeographic footprints helps to understand cryptic diversity detected in two marine amphipods widespread in the Mediterranean basin

Amphipods of the genus Gammarus are a vital component of macrozoobenthic communities in European inland and coastal, marine and brackish waters of the Mediterranean and the Black Sea. Exceptional levels of cryptic diversity have been revealed for several widespread freshwater Gammarus species in Europe. No comprehensive assessment has yet been made for brackishwater counterparts, such as Gammarus aequicauda and G. insensibilis, which are among the most widely dispersed members of the so-called "G. locusta group" in the Mediterranean and in the Black Sea. Here we probe the diversity of these morphospecies examining the partitioning of mtDNA and nDNA across multiple populations along their distribution range and discuss it within the regional paleogeographic framework. We gathered molecular data from a collection of 166 individuals of G. aequicauda and G. insensibilis from 47 locations along their distribution range in the Mediterranean including the Black Sea. They were amplified for both mitochondrial COI and 16S rRNA as well as the nuclear 28S rRNA. All five MOTU delimitation methods (ABGD, BIN, bPTP, GMYC single and multiple threshold models) applied revealed deep divergence between Black Sea and Mediterranean populations in both G. aequicauda and G. insensibilis. There were eight distinct MOTUs delimited for G. aequicauda (6-18% K2P) and 4 MOTUs for G. insensibilis (4-14% K2P). No sympatric MOTUs were detected throughout their distribution range. Multimarker time-calibrated phylogeny indicated that divergence of both G. aequicauda and G. insensibilis species complexes started already in the late Oligocene/early Miocene with the split between clades inhabiting eastern and western part of the Mediterranean occurring in both species at the similar time. Our results indicate a high cryptic diversity within Mediterranean brackishwater Gammarus, similar to that observed for freshwater counterparts. Moreover, the phylogenetic history combined with the current geographic distribution indicate that the evolution of both studied Gammarus morphogroups has been strongly connected with the geological events in the Mediterranean Basin and it reflect the turbulent history of the area.

Differences in substrate specificity of V. cholerae FabH enzymes suggest new approaches for the development of novel antibiotics and biofuels

Vibrio cholerae, the causative pathogen of the life-threatening infection cholera, encodes two copies of β-ketoacyl-acyl carrier protein synthase III (vcFabH1 and vcFabH2). vcFabH1 and vcFabH2 are pathogenic proteins associated with fatty acid synthesis, lipid metabolism, and potential applications in biofuel production. Our biochemical assays characterize vcFabH1 as exhibiting specificity for acetyl-CoA and CoA thioesters with short acyl chains, similar to that observed for FabH homologs found in most gram-negative bacteria. vcFabH2 prefers medium chain-length acyl-CoA thioesters, particularly octanoyl-CoA, which is a pattern of specificity rarely seen in bacteria. Structural characterization of one vcFabH1 and six vcFabH2 structures determined in either apo form or in complex with acetyl-CoA/octanoyl-CoA indicate that the substrate-binding pockets of vcFabH1 and vcFabH2 are of different sizes, accounting for variations in substrate chain-length specificity. An unusual and unique feature of vcFabH2 is its C-terminal fragment that interacts with both the substrate-entrance loop and the dimer interface of the enzyme. Our discovery of the pattern of substrate specificity of both vcFabH1 and vcFabH2 can potentially aid the development of novel antibacterial agents against V. cholerae. Additionally, the distinctive substrate preference of FabH2 in V. cholerae and related facultative anaerobes conceivably make it an attractive component of genetically engineered bacteria used for commercial biofuel production.

Characterizations of handwashing sink activities in a single hospital medical intensive care unit

BACKGROUND

Handwashing sink drains are increasingly implicated as a potential reservoir of antibiotic-resistant bacteria in hospital outbreaks; however, usage patterns that may promote this source remain unknown.

AIM

To understand behaviours in the intensive care unit (ICU) that may facilitate establishment and nosocomial transmission of multidrug-resistant Gram negatives from a sink-trap reservoir to a patient.

METHODS

Motion-sensitive cameras captured anonymized activity paired with periodic in-person observations during a quality investigation from four ICU sinks (two patient rooms and two patient bathrooms) in a university hospital.

FINDINGS

We analysed 4810 sink videos from 60 days in patient rooms (3625) and adjoining bathrooms (1185). There was a false-positive rate of 38% (1837 out of 4810) in which the camera triggered but no sink interaction occurred. Of the 2973 videos with analysed behaviours there were 5614 observed behaviours which were assessed as: 37.4% medical care, 29.2% additional behaviours, 17.0% hand hygiene, 7.2% patient nutrition, 5.0% environmental care, 4.2% non-medical care. Handwashing was only 4% (224 out of 5614) of total behaviours. Sub-analysis of 2748 of the later videos further categorized 56 activities where a variety of nutrients, which could promote microbial growth, were disposed of in the sink.

CONCLUSION

Several non-hand hygiene activities took place regularly in ICU handwashing sinks; these may provide a mechanism for nosocomial transmission and promotion of bacterial growth in the drain. Redesigning hospital workflow and sink usage may be necessary as it becomes apparent that sink drains may be a reservoir for transmission of multidrug-resistant bacteria.

Databases, Repositories, and Other Data Resources in Structural Biology

Structural biology, like many other areas of modern science, produces an enormous amount of primary, derived, and "meta" data with a high demand on data storage and manipulations. Primary data come from various steps of sample preparation, diffraction experiments, and functional studies. These data are not only used to obtain tangible results, like macromolecular structural models, but also to enrich and guide our analysis and interpretation of various biomedical problems. Herein we define several categories of data resources, (a) Archives, (b) Repositories, (c) Databases, and (d) Advanced Information Systems, that can accommodate primary, derived, or reference data. Data resources may be used either as web portals or internally by structural biology software. To be useful, each resource must be maintained, curated, as well as integrated with other resources. Ideally, the system of interconnected resources should evolve toward comprehensive "hubs", or Advanced Information Systems. Such systems, encompassing the PDB and UniProt, are indispensable not only for structural biology, but for many related fields of science. The categories of data resources described herein are applicable well beyond our usual scientific endeavors.

A new option for definitive burn wound closure - pair matching type of retrospective case-control study of hand burns in the hospitalised patients group in the Dr Stanislaw Sakiel Centre for Burn Treatment between 2009 and 2015

Nearly 80% of all burns include the hands of affected individuals. Skin grafting is the gold standard in burns treatment, but in the case of the burn wound bed, it may require the necessity of utilising skin substitutes to facilitate closure. The aim of this study is to assess the impact of a porcine-derived wound dressing (Oasis™) for application to hand burns compared to a synthetic dressing (Suprathel™). Comparative assessments were made, including the time to heal, quality of healing and pain intensity. A retrospective, unblinded, matching pair case-control of hand burns was performed. A control group of 24 patients was treated with Suprathel dressing, and a study group of six patients underwent application of the Oasis dressing. The wound healing process was evaluated by taking histopathological specimens and also utilising the Bates-Jensen Wound Assessment Tool. A 10-cm Visual Analogue Scale (VAS) was used for pain assessment. Other parameters measured included dressing loss because of infection and the need of rehabilitation. The progress of wound healing on the fourth day in the study group was 30%. A decrease in the level of pain was recorded on the fourth day after surgery. There was a decrease of 5% in the risk of rehabilitation in the treatment group.

Sharing Big Data

Macromolecular Big Data provide numerous challenges and a number of initiatives that are starting to overcome these issues are discussed.

MUFINS: multi-formalism interaction network simulator

Systems Biology has established numerous approaches for mechanistic modeling of molecular networks in the cell and a legacy of models. The current frontier is the integration of models expressed in different formalisms to address the multi-scale biological system organization challenge. We present MUFINS (MUlti-Formalism Interaction Network Simulator) software, implementing a unique set of approaches for multi-formalism simulation of interaction networks. We extend the constraint-based modeling (CBM) framework by incorporation of linear inhibition constraints, enabling for the first time linear modeling of networks simultaneously describing gene regulation, signaling and whole-cell metabolism at steady state. We present a use case where a logical hypergraph model of a regulatory network is expressed by linear constraints and integrated with a Genome-Scale Metabolic Network (GSMN) of mouse macrophage. We experimentally validate predictions, demonstrating application of our software in an iterative cycle of hypothesis generation, validation and model refinement. MUFINS incorporates an extended version of our Quasi-Steady State Petri Net approach to integrate dynamic models with CBM, which we demonstrate through a dynamic model of cortisol signaling integrated with the human Recon2 GSMN and a model of nutrient dynamics in physiological compartments. Finally, we implement a number of methods for deriving metabolic states from ~omics data, including our new variant of the iMAT congruency approach. We compare our approach with iMAT through the analysis of 262 individual tumor transcriptomes, recovering features of metabolic reprogramming in cancer. The software provides graphics user interface with network visualization, which facilitates use by researchers who are not experienced in coding and mathematical modeling environments.

A public database of macromolecular diffraction experiments

The low reproducibility of published experimental results in many scientific disciplines has recently garnered negative attention in scientific journals and the general media. Public transparency, including the availability of `raw' experimental data, will help to address growing concerns regarding scientific integrity. Macromolecular X-ray crystallography has led the way in requiring the public dissemination of atomic coordinates and a wealth of experimental data, making the field one of the most reproducible in the biological sciences. However, there remains no mandate for public disclosure of the original diffraction data. The Integrated Resource for Reproducibility in Macromolecular Crystallography (IRRMC) has been developed to archive raw data from diffraction experiments and, equally importantly, to provide related metadata. Currently, the database of our resource contains data from 2920 macromolecular diffraction experiments (5767 data sets), accounting for around 3% of all depositions in the Protein Data Bank (PDB), with their corresponding partially curated metadata. IRRMC utilizes distributed storage implemented using a federated architecture of many independent storage servers, which provides both scalability and sustainability. The resource, which is accessible via the web portal at http://www.proteindiffraction.org, can be searched using various criteria. All data are available for unrestricted access and download. The resource serves as a proof of concept and demonstrates the feasibility of archiving raw diffraction data and associated metadata from X-ray crystallographic studies of biological macromolecules. The goal is to expand this resource and include data sets that failed to yield X-ray structures in order to facilitate collaborative efforts that will improve protein structure-determination methods and to ensure the availability of `orphan' data left behind for various reasons by individual investigators and/or extinct structural genomics projects.

Transforming biomedical and structural data into information and knowledge

The LabDB laboratory information management system (LIMS) tracks, organizes and analyzes data from chemical and solution management, protein production, crystallization, diffraction, structure solution, and in vitro biochemical and biophysical experiments. The system is comprised of multiple modules specialized for different tasks, such as the Xtaldb system for crystallization or the hkldb module of the HKL-3000 suite for diffraction data collection and structure solution. The biochemical/biophysical experiments tracked by LabDB include spectrophotometric binding and kinetics, thermal shift binding, isothermal titration calorimetry (ITC) and protein quantitation. These tools associate functional and structural experiments, for example, for selecting likely substrates for co-crystallization and soaking experiments. Whenever possible, the system harvests data with no or minimal user intervention from laboratory hardware. Devices that may connect to or import data into LabDB include crystal observation (Rigaku Minstrel HT and Formulatrix Rock Imager), liquid handling (Formulatrix Rock Maker and Emerald Opti-Matrix Maker), chromatography (GE Healthcare AKTA), quantitation (Caliper LabChip GX II and Bio-Rad Gel Doc EZ), RT-PCR (Applied Biosystems 7900HT and Bio-Rad C1000/CFX96) and ITC (MicroCal iTC-200) systems. LabDB is used by two high-throughput PSI:Biology centers (MCSG and NYSGRC) as well as other major NIH consortia (the Center for Structural Genomics of Infectious Diseases and the Enzyme Function Initiative), and track millions of experiments on tens of thousands of targets.[1] The system also provides extensive data mining and analysis tools for translating raw experimental data into information and knowledge. We present examples of analyses generated by the system useful in designing new experiments.

Data management in the modern structural biology and biomedical research environment

Modern high-throughput structural biology laboratories produce vast amounts of raw experimental data. The traditional method of data reduction is very simple-results are summarized in peer-reviewed publications, which are hopefully published in high-impact journals. By their nature, publications include only the most important results derived from experiments that may have been performed over the course of many years. The main content of the published paper is a concise compilation of these data, an interpretation of the experimental results, and a comparison of these results with those obtained by other scientists.Due to an avalanche of structural biology manuscripts submitted to scientific journals, in many recent cases descriptions of experimental methodology (and sometimes even experimental results) are pushed to supplementary materials that are only published online and sometimes may not be reviewed as thoroughly as the main body of a manuscript. Trouble may arise when experimental results are contradicting the results obtained by other scientists, which requires (in the best case) the reexamination of the original raw data or independent repetition of the experiment according to the published description of the experiment. There are reports that a significant fraction of experiments obtained in academic laboratories cannot be repeated in an industrial environment (Begley CG & Ellis LM, Nature 483(7391):531-3, 2012). This is not an indication of scientific fraud but rather reflects the inadequate description of experiments performed on different equipment and on biological samples that were produced with disparate methods. For that reason the goal of a modern data management system is not only the simple replacement of the laboratory notebook by an electronic one but also the creation of a sophisticated, internally consistent, scalable data management system that will combine data obtained by a variety of experiments performed by various individuals on diverse equipment. All data should be stored in a core database that can be used by custom applications to prepare internal reports, statistics, and perform other functions that are specific to the research that is pursued in a particular laboratory.This chapter presents a general overview of the methods of data management and analysis used by structural genomics (SG) programs. In addition to a review of the existing literature on the subject, also presented is experience in the development of two SG data management systems, UniTrack and LabDB. The description is targeted to a general audience, as some technical details have been (or will be) published elsewhere. The focus is on "data management," meaning the process of gathering, organizing, and storing data, but also briefly discussed is "data mining," the process of analysis ideally leading to an understanding of the data. In other words, data mining is the conversion of data into information. Clearly, effective data management is a precondition for any useful data mining. If done properly, gathering details on millions of experiments on thousands of proteins and making them publicly available for analysis-even after the projects themselves have ended-may turn out to be one of the most important benefits of SG programs.