Trivalent and quadrivalent seasonal influenza vaccine in adults aged 60 and older: a systematic review and network meta-analysis

OBJECTIVES

To compare the efficacy of influenza vaccines of any valency for adults 60 years and older.

DESIGN AND SETTING

Systematic review with network meta-analysis (NMA) of randomised controlled trials (RCTs). MEDLINE, EMBASE, JBI Evidence-Based Practice (EBP) Database, PsycINFO, and Cochrane Evidence -Based Medicine database were searched from inception to 20 June 20, 2022. Two reviewers screened, abstracted, and appraised articles (Cochrane Risk of Bias (ROB) 2.0 tool) independently. We assessed certainty of findings using Confidence in Network Meta-Analysis and Grading of Recommendations, Assessment, Development and Evaluations approaches. We performed random-effects meta-analysis and network meta-analysis (NMA), and estimated odds ratios (ORs) for dichotomous outcomes and incidence rate ratios (IRRs) for count outcomes along with their corresponding 95% confidence intervals (CIs) and prediction intervals.

PARTICIPANTS

Older adults (≥60 years old) receiving an influenza vaccine licensed in Canada or the USA (vs placebo, no vaccine, or any other licensed vaccine), at any dose.

MAIN OUTCOME MEASURES

Laboratory-confirmed influenza (LCI) and influenza-like illness (ILI). Secondary outcomes were the number of vascular adverse events, hospitalisation for acute respiratory infection (ARI) and ILI, inpatient hospitalisation, emergency room (ER) visit for ILI, outpatient visit, and mortality, among others.

RESULTS

We included 41 RCTs and 15 companion reports comprising 8 vaccine types and 206 032 participants. Vaccines may prevent LCI compared with placebo, with high-dose trivalent inactivated influenza vaccine (IIV3-HD) (NMA: 9 RCTs, 52 202 participants, OR 0.23, 95% confidence interval (CI) (0.11 to 0.51), low certainty of evidence) and recombinant influenza vaccine (RIV) (OR 0.25, 95%CI (0.08 to 0.73), low certainty of evidence) among the most efficacious vaccines. Standard dose trivalent IIV3 (IIV3-SD) may prevent ILI compared with placebo, but the result was imprecise (meta-analysis: 2 RCTs, 854 participants, OR 0.39, 95%CI (0.15 to 1.02), low certainty of evidence). Any HD was associated with prevention of ILI compared with placebo (NMA: 9 RCTs, 65 658 participants, OR 0.38, 95%CI (0.15 to 0.93)). Adjuvanted quadrivalent IIV (IIV4-Adj) may be associated with the least vascular adverse events, but the results were very uncertain (NMA: eight 8 RCTs, 57 677 participants, IRR 0.18, 95%CI (0.07 to 0.43), very low certainty of evidence). RIV on all-cause mortality may be comparable to placebo (NMA: 20 RCTs, 140 577 participants, OR 1.01, 95%CI (0.23 to 4.49), low certainty of evidence).

CONCLUSIONS

This systematic review demonstrated efficacy associated with IIV3-HD and RIV vaccines in protecting older persons against LCI. RIV vaccine may reduce all-cause mortality when compared with other vaccines, but the evidence is uncertain. Differences in efficacy between influenza vaccines remain uncertain with very low to moderate certainty of evidence.

PROSPERO REGISTRATION NUMBER

CRD42020177357.

Epidemiology of healthcare-associated Pseudomonas aeruginosa in intensive care units: Are sink drains to blame?

BACKGROUND

Pseudomonas aeruginosa (PA) is a common cause of healthcare-associated infections (PA-HAI) in the intensive care unit (ICU). We aimed to describe the epidemiology of PA-HAI in ICUs in Ontario, Canada, and determine whether we could identify episodes of sink-to-patient PA transmission.

METHODS

This was a prospective cohort study of patients in six ICUs from 2018-2019, with retrieval of PA clinical isolates, and PA-screening of antimicrobial resistant organism surveillance rectal swabs, and of sink drain, air, and faucet samples. All PA isolates underwent whole genome sequencing. PA-HAI was defined using US National Healthcare Safety Network criteria. ICU-acquired PA was defined as PA isolated from specimens obtained >48 hours after ICU admission in those with prior negative rectal swabs. Sink-to-patient PA transmission was defined as ICU-acquired PA with close genomic relationship to isolate(s) previously recovered from sinks in a room/bedspace occupied 3-14 days prior to the relevant patient isolate.

RESULTS

Over ten months, 72 PA-HAI occurred among 60/4263 admissions. The rate of PA-HAI was 2.40 per 1000 patient-ICU days; higher in patients who were PA-colonized on admission. PA-HAI was associated with longer stay (median 26 vs 3 days uninfected, p<0.001) and contributed to death in 22/60 cases (36.7%). Fifty-eight admissions with ICU-acquired PA were identified, contributing 35/72 (48.6%) PA-HAI. Four patients with five PA-HAI (6.9%) had closely related isolates previously recovered from their room/bedspace sinks.

CONCLUSIONS

Nearly half of PA causing HAI appeared to be acquired in ICUs, and 7% of PA-HAI were associated with sink-to-patient transmission. Sinks may be an underrecognized reservoir for HAIs.

Influence of Atherosclerotic Risk Factors on the Effectiveness of Therapeutic Ultrasound Cavitation for Flow Augmentation

BACKGROUND

Shear created by inertial cavitation of microbubbles by ultrasound augments limb and myocardial perfusion and can reverse tissue ischemia. Our aim was to determine whether this therapeutic bioeffect is attenuated by atherosclerotic risk factors that are known to impair shear-mediated vasodilation and adversely affect microvascular reactivity.

METHODS

In mice, lipid-stabilized decafluorobutane microbubbles (2 × 108) were administered intravenously while exposing a proximal hind limb to ultrasound (1.3 MHz, 1.3 mechanical index, pulsing interval 5 seconds) for 10 minutes. Murine strains included wild-type mice and severely hyperlipidemic mice at 15, 35, or 52 weeks of age as a model of aging and elevated cholesterol, and obese db/db mice (≈15 weeks) with severe insulin resistance. Quantitative contrast-enhanced ultrasound perfusion imaging was performed to assess microvascular perfusion in the control and ultrasound-exposed limb. An in situ electrochemical probe and in vivo biophotonic imaging were used to assess limb nitric oxide (NO) and adenosine triphosphosphate concentrations, respectively.

RESULTS

Microvascular perfusion was significantly increased by several fold in the cavitation-exposed limb versus control limb for all murine strains and ages (P < .001). In wild-type and hyperlipidemic mice, hyperemia from cavitation was attenuated in the 2 older age groups (P < .01). In young mice (15 weeks), perfusion in cavitation-exposed muscle was less in both the hyperlipidemic mice and the obese db/db mice compared with corresponding wild-type mice. Using young hyperlipidemic mice as a model for flow impairment, limb NO production after cavitation was reduced but adenosine triphosphosphate production was unaltered when compared with age-matched wild-type mice.

CONCLUSIONS

In mice, ultrasound cavitation of microbubbles increases limb perfusion by several fold even in the presence of traditional atherosclerotic risk factors. However, older age, hyperlipidemia, and insulin resistance modestly attenuate the degree of flow augmentation, which could impact the degree of flow response in current clinical trials in patients with critical limb ischemia.

A comparison of endovascular repair to medical management for acute vs subacute uncomplicated type B aortic dissections

OBJECTIVE

Thoracic endovascular aortic repair (TEVAR) has emerged as a viable option of treatment for uncomplicated type B aortic dissection (UTBAD) due to the potential for inducing favorable aortic remodeling. The aim of this study is to compare outcomes of UTBAD treated medically or with TEVAR in either the acute (1 to 14 days) or subacute period (2 weeks to 3 months).

METHODS

Patients with UTBAD between 2007 and 2019 were identified using the TriNetX Network. The cohort was stratified by treatment type (medical management; TEVAR during the acute period; TEVAR during the subacute period). Outcomes including mortality, endovascular reintervention, and rupture were analyzed after propensity matching.

RESULTS

Among 20,376 patients with UTBAD, 18,840 were medically managed (92.5%), 1099 patients were in the acute TEVAR group (5.4%), and 437 patients were in the subacute TEVAR group (2.1%). The acute TEVAR group had higher rates of 30-day and 3-year rupture (4.1% vs 1.5%; P < .001; 9.9% vs 3.6%; P < .001) and 3-year endovascular reintervention (7.6% vs 1.6%; P < .001), similar 30-day mortality (4.4% vs 2.9%; P < .068), and lower 3-year survival compared with medical management (86.6% vs 83.3%; P = .041). The subacute TEVAR group had similar rates of 30-day mortality (2.3% vs 2.3%; P = 1), 3-year survival (87.0% vs 88.8%; P = .377) and 30-day and 3-year rupture (2.3% vs 2.3%; P = 1; 4.6% vs 3.4%; P = .388), with significantly higher rates of 3-year endovascular reintervention (12.6% vs 7.8%; P = .019) compared with medical management. The acute TEVAR group had similar rates of 30-day mortality (4.2% vs 2.5%; P = .171), rupture (3.0% vs 2.5%; P = .666), significantly higher rates of 3-year rupture (8.7% vs 3.5%; P = .002), and similar rates of 3-year endovascular reintervention (12.6% vs 10.6%; P = .380) compared with the subacute TEVAR group. There was significantly higher 3-year survival (88.5% vs 84.0%; P = .039) in the subacute TEVAR group compared with the acute TEVAR group.

CONCLUSIONS

Our results found lower 3-year survival in the acute TEVAR group compared with the medical management group. There was no 3-year survival benefit found in patients with UTBAD who underwent subacute TEVAR compared with medical management. This suggests the need for further studies looking at the necessity for TEVAR when compared with medical management for UTBAD as it is non-inferior to medical management. Higher rates of 3-year survival and lower rates of 3-year rupture in the subacute TEVAR group compared with the acute TEVAR group suggest superiority of subacute TEVAR. Further investigations are needed to determine the long-term benefit and optimal timing of TEVAR for acute UTBAD.

Older patients with nonspecific complaints at the Emergency Department are at risk of adverse health outcomes

OBJECTIVE

Older adults at the Emergency Department (ED) often present with nonspecific complaints (NSC) such as 'weakness' or 'feeling unwell'. Health care workers may underestimate illness in patients with NSC, leading to adverse health outcomes. This study compares characteristics and outcomes of NSC-patients versus specific complaints (SC) patients.

METHODS

Cohort study in patients ≥ 70 years in two Dutch EDs. NSC was classified according to the BANC-study-framework based on the medical history in the ED letter, before additional diagnostics took place. A second classification was performed at the end of the ED visit/hospital admission. Primary outcomes were functional decline, institutionalization, and mortality at 30 days.

RESULTS

26% (n = 228) of a total of 888 included patients presented with NSC. Compared with SC-patients, NSC-patients were older, more frail, and more frequently female. NSC-patients had a higher risk of functional decline and institutionalization at 30 days (adjusted ORs 1.84, 95% CI 1.27 - 2.72, and 2.46, 95% CI 1.51-4.00, respectively), but not mortality (adjusted OR 1.26, 95% CI 0.58 - 2.73). Reclassification to a specific complaint after the ED visit or hospital admission occurred in 54% of NSC-patients.

CONCLUSION

NSC occur especially in older, frail female patients and are associated with an increased risk of functional decline and institutionalization, even after adjustment for worse baseline status. In half of the patients, a specific complaint revealed during ED or hospital stay. Physicians at the ED should consider NSC as a red flag needing appropriate observation and evaluation of underlying serious conditions and needs of this vulnerable patient group.

Elevated LDL (Low-Density Lipoprotein) Cholesterol Increases Microvascular Endothelial VWF (von Willebrand Factor) and Thromboinflammation After Myocardial Infarction

BACKGROUND

In reperfused myocardial infarction, VWF (von Willebrand factor)-mediated platelet adhesion contributes to impaired microvascular reflow and possibly also to postmyocardial infarction inflammation. We hypothesized that postischemic thromboinflammatory processes are worsened by elevated LDL (low-density lipoprotein) cholesterol.

METHODS

Myocardial ischemia-reperfusion or sham procedure was performed in wild-type mice and hyperlipidemic mice deficient for the LDL receptor and Apobec-1 (apolipoprotein-B mRNA editing enzyme catalytic polypeptide-1; DKO [double knockout]). DKO subgroups were treated with N-acetylcysteine, which inhibits pro-adhesive VWF multimers or with recombinant ADAMTS13 (a disintegrin and metalloproteinase with thrombospondin motifs-13), which enzymatically cleaves endothelial surface-associated VWF. Myocardial contrast echocardiography perfusion imaging and molecular imaging for VWF, platelet GP Ibα, and leukocyte CD18 were performed 30 minutes post-reperfusion. Histology, infarct sizing, and echocardiography were performed at 1.5 or 72 hours; late echocardiography was performed at day 21.

RESULTS

After ischemia-reperfusion, DKO compared with wild-type mice had ≈2-fold higher (P<0.05) risk area signal for microvascular platelet adhesion, VWF, and CD18; greater impairment in microvascular reflow, and 2-fold larger infarct size. Treatment of DKO mice with N-acetylcysteine and ADAMTS13 reduced molecular imaging signal for microvascular platelet adhesion, VWF, and CD18; improved early microvascular reflow; and reduced eventual infarct size. ADAMTS13 suppressed the postmyocardial infarction neutrophil and monocyte infiltration, enhanced the time-dependent recovery of left ventricular systolic function, and prevented late left ventricular remodeling.

CONCLUSIONS

In reperfused myocardial infarction, elevated LDL cholesterol promotes thromboinflammation through excess microvascular endothelial VWF and platelet adhesion, resulting in less microvascular reflow and larger infarct size. In the presence of elevated LDL cholesterol, therapies that suppress endothelial-associated VWF can promote recovery of left ventricular function and protect against remodeling.

Clinical characteristics, management, and outcomes of acute heart failure patients in Central Asia

Funding Acknowledgements

Type of funding sources: None.

Background

Cardiovascular disease (CVD) is the leading cause of death in Central Asia. In 2019, crude mortality rate in the region was 348.13 per 100,000 population. Heart failure (HF) is important CVD subtype owing to even worse outcome. There has been a dearth of information on the epidemiology of HF in Central Asia.

Purpose

we aimed to describe aetiology, comorbidities, adherence to guideline-directed medical therapy (GDMT), and outcomes in patients hospitalised for heart failure in Central Asian population.

Methods

the retrospective analysis included 538 patients hospitalised for decompensated heart failure in a tertiary hospital from December 2011 to December 2019. Inclusion criteria were (i) age ≥18 years; (ii) hospitalisation for HF treatment. Exclusion criteria were (i) pregnancy; (ii) comorbidity with survival time considered to be &lt;1 year on the basis of patients` medical history; (iii) acute HF caused by acute myocardial infarction, metabolic, toxic or infectious disorders. Primary outcome was one-year all-cause mortality, secondary outcome - readmission for HF at one year. Given that the data had been collected retrospectively, informed consent was not obtained, nevertheless, local ethics committee approved the study.

Results

Central Asian patients were relatively young (mean age 64.0 years), 61.2% of them were male, 77.7% had ischemic heart disease, 8.7% rheumatic heart disease, 32.2% obstructive pulmonary disease, 47.7% atrial fibrillation/flutter, 45.7% hyperlipidemia, 72.1% hypertension, and 31.6% diabetes mellitus. Use of GDMT at discharge was 76.0% for beta-blockers, 29.7% for angiotensin-converting enzyme inhibitors, 21.2% for angiotensin II receptor blockers, 71.9% for mineralocorticoid receptor antagonists. Only 3.9% of patients were implanted with a pacemaker and 0.9% with an implantable cardioverter defibrillator. All-cause mortality at one year was 19.0%, with no difference between patients with preserved and reduced ejection fraction (14.9 vs. 19.9%, p=0.243). However, patients with preserved ejection fraction were less likely to experience a readmission for heart failure at one year (13.9 vs. 29.3%, p=0.002).

Conclusions

results of the analysis showed that Central Asian patients are relatively young, mostly male, with high prevalence of ischemic heart disease, and reduced ejection fraction, and lower rate of GDMT use and device therapy.

89. On-going impact of the SARS-CoV-2 pandemic on the evolution of carbapenemase-producing Enterobacterales in Ontario, Canada

Background

The spread of carbapenemase-producing Enterobacterales (CPE) is global threat. Numerous outbreaks of CPE have been reported during the COVID-19 pandemic. We describe the impact of of the SARS-CoV-2 pandemic on the emergence of CPE in south-central Ontario, Canada.

Incidence of clinical isolates of CPE and isolates with different CPE genes in Toronto/Peel region, 2017–2021.

The upper panel shows the incidence of patients with clinical isolates of CPE by year and quarter from q4 2007 to q1 2022. The lower panel shows the incidence of patients with clinical isolates with different carbapenemase genes by fiscal year during the same period.

Methods

TIBDN has performed population-based surveillance for CPE in Toronto/Peel region (pop 4.5M) from first identified isolate in 2007. All laboratories test/refer all carbapenem non-susceptible Enterobacterial isolates for identification of CPE. Hospital charts are reviewed and patients/physicians interviewed. Population data are obtained from Statistics Canada.

Results

From 10/2007 to 3/31/2022, 1367 persons colonized or infected with CPE were identified. Their median age was 68.7yrs (IQR 54–78yrs); 761 (56%) were male. 772 (56%) were colonized when first identified; 115 (8.4%) were bacteremic at identification or subsequently developed bacteremia. The most common organisms were E. coli (651, 48%), K. pneumoniae (436, 32%), Enterobacter spp. (146, 11%), Citrobacter spp (62, 5%); the most common genes were NDM±OXA-48 (722, 53%), OXA-48-like (341, 25%), KPC (225, 16%), VIM (44, 3%). The incidence of CPE infections increased steadily until 3/2020 then declined by 61% and remained stable until 3/2022 (Figure, upper panel). The decline was greater for E. coli (56% decrease), K. pneumoniae (62%) than for Enterobacter spp. (30%) and other species (19%). It occurred in all genes in 2020; however, KPC containing organisms increased again in 2021 (Figure, lower panel).

Conclusion

The advent of the COVID-19 pandemic was associated with an immediate, substantial decline in the incidence of patients with CPE in our population area. This decline occurred in both isolates with genes usually occurring in cases imported from other countries, and in those usually occurring in cases associated with transmission within Canadian hospitals. Decreased travel and enhanced infection prevention and control in hospitals may both have contributed to reductions in CPE during the pandemic.

Disclosures

All Authors: No reported disclosures.

Multi-Scale Investigation of Human Renal Tissue in Three Dimensions

Histopathology as a diagnostic mainstay for tissue evaluation is strictly a 2D technology. Combining and supplementing this technology with 3D imaging has been proposed as one future avenue towards refining comprehensive tissue analysis. To this end, we have developed a laboratory-based X-ray method allowing for the investigation of tissue samples in three dimensions with isotropic volume information. To assess the potential of our method for micro-morphology evaluation, we selected several kidney regions from three patients with cystic kidney disease, obstructive nephropathy and diabetic glomerulopathy. Tissue specimens were processed using our in-house-developed X-ray eosin stain and investigated with a commercial microCT and our in-house-built NanoCT. The microCT system provided overview scans with voxel sizes of [Formula: see text] and the NanoCT was employed for higher resolutions including voxel sizes from [Formula: see text] to 210 nm. We present a methodology allowing for a precise micro-morphologic investigation in three dimensions which is compatible with conventional histology. Advantages of our methodology are its versatility with respect to multi-scale investigations, being laboratory-based, allowing for non-destructive imaging and providing isotropic volume information. We believe, that after future developmental work this method might contribute to advanced multi-modal tissue diagnostics.

Medical Masks Versus N95 Respirators for Preventing COVID-19 Among Health Care Workers : A Randomized Trial

BACKGROUND

It is uncertain if medical masks offer similar protection against COVID-19 compared with N95 respirators.

OBJECTIVE

To determine whether medical masks are noninferior to N95 respirators to prevent COVID-19 in health care workers providing routine care.

DESIGN

Multicenter, randomized, noninferiority trial. (ClinicalTrials.gov: NCT04296643).

SETTING

29 health care facilities in Canada, Israel, Pakistan, and Egypt from 4 May 2020 to 29 March 2022.

PARTICIPANTS

1009 health care workers who provided direct care to patients with suspected or confirmed COVID-19.

INTERVENTION

Use of medical masks versus fit-tested N95 respirators for 10 weeks, plus universal masking, which was the policy implemented at each site.

MEASUREMENTS

The primary outcome was confirmed COVID-19 on reverse transcriptase polymerase chain reaction (RT-PCR) test.

RESULTS

In the intention-to-treat analysis, RT-PCR-confirmed COVID-19 occurred in 52 of 497 (10.46%) participants in the medical mask group versus 47 of 507 (9.27%) in the N95 respirator group (hazard ratio [HR], 1.14 [95% CI, 0.77 to 1.69]). An unplanned subgroup analysis by country found that in the medical mask group versus the N95 respirator group RT-PCR-confirmed COVID-19 occurred in 8 of 131 (6.11%) versus 3 of 135 (2.22%) in Canada (HR, 2.83 [CI, 0.75 to 10.72]), 6 of 17 (35.29%) versus 4 of 17 (23.53%) in Israel (HR, 1.54 [CI, 0.43 to 5.49]), 3 of 92 (3.26%) versus 2 of 94 (2.13%) in Pakistan (HR, 1.50 [CI, 0.25 to 8.98]), and 35 of 257 (13.62%) versus 38 of 261 (14.56%) in Egypt (HR, 0.95 [CI, 0.60 to 1.50]). There were 47 (10.8%) adverse events related to the intervention reported in the medical mask group and 59 (13.6%) in the N95 respirator group.

LIMITATION

Potential acquisition of SARS-CoV-2 through household and community exposure, heterogeneity between countries, uncertainty in the estimates of effect, differences in self-reported adherence, differences in baseline antibodies, and between-country differences in circulating variants and vaccination.

CONCLUSION

Among health care workers who provided routine care to patients with COVID-19, the overall estimates rule out a doubling in hazard of RT-PCR-confirmed COVID-19 for medical masks when compared with HRs of RT-PCR-confirmed COVID-19 for N95 respirators. The subgroup results varied by country, and the overall estimates may not be applicable to individual countries because of treatment effect heterogeneity.

PRIMARY FUNDING SOURCE

Canadian Institutes of Health Research, World Health Organization, and Juravinski Research Institute.

“Are you breathing?” – Design, build and testing of a low-cost, portable respiratory rate monitor

A patient’s respiratory rate is one of the critical vital signs that is a determinant of patient well-being. However, it is all too often neglected or misreported by health care professionals. This study presents the design, build and testing of a low-cost, portable monitor to facilitate accurate reporting of respiratory rate. The monitor comprised a thermistor-based transducer to capture the breath cycle of patients based on the temperature differential created across the thermistor. The signal was conditioned and processed such that the signal could be analysed to identify the peaks and ultimately determine the respiratory rate. For a total cost at the time of development of less than C40, the integrated system demonstrated a modest average error of 5.6% across a range of different ambient temperatures, rate and depth of breathing, and orifice of breathing. This is comparable with other commercial and custom devices. The presented monitor may be of interest for use in an emergency room or clinical setting, especially in severely resource-constrained countries.

Ibrutinib Inhibits BMX-Dependent Endothelial VCAM-1 Expression In Vitro and Pro-Atherosclerotic Endothelial Activation and Platelet Adhesion In Vivo

Introduction

Inflammatory activation of the vascular endothelium leads to overexpression of adhesion molecules such as vascular cell adhesion molecule-1 (VCAM-1), contributing to the pro-thrombotic state underpinning atherogenesis. While the role of TEC family kinases (TFKs) in mediating inflammatory cell and platelet activation is well defined, the role of TFKs in vascular endothelial activation remains unclear. We investigated the role of TFKs in endothelial cell activation in vitro and in a nonhuman primate model of diet-induced atherosclerosis in vivo.

Methods and Results

In vitro, we found that ibrutinib blocked activation of the TFK member, BMX, by vascular endothelial growth factors (VEGF)-A in human aortic endothelial cells (HAECs). Blockade of BMX activation with ibrutinib or pharmacologically distinct BMX inhibitors eliminated the ability of VEGF-A to stimulate VCAM-1 expression in HAECs. We validated that treatment with ibrutinib inhibited TFK-mediated platelet activation and aggregation in both human and primate samples as measured using flow cytometry and light transmission aggregometry. We utilized contrast-enhanced ultrasound molecular imaging to measure platelet GPIbα and endothelial VCAM-1 expression in atherosclerosis-prone carotid arteries of obese nonhuman primates. We observed that the TFK inhibitor, ibrutinib, inhibited platelet deposition and endothelial cell activation in vivo.

Conclusion

Herein we found that VEGF-A signals through BMX to induce VCAM-1 expression in endothelial cells, and that VCAM-1 expression is sensitive to ibrutinib in vitro and in atherosclerosis-prone carotid arteries in vivo. These findings suggest that TFKs may contribute to the pathogenesis of atherosclerosis and could represent a novel therapeutic target.

422. Sustainability of Improvements to Hand Hygiene Performance Throughout the COVID-19 Pandemic

Background

Hand hygiene (HH) is a standard infection prevention and control precaution to be applied in healthcare settings to prevent transmission of COVID-19. Many healthcare institutions observed significant improvements in HH performance during wave one of the COVID-19 pandemic but the sustainability of this change is unknown. Our aim was to evaluate long-term HH performance throughout subsequent waves of the pandemic across acute care hospitals in Ontario, Canada.

Methods

HH adherence was measured using a previously validated group electronic monitoring system which was installed on all alcohol handrub and sink soap dispensers inside and outside each patient room across 56 inpatient units (35 wards and 21 critical care units) spanning 13 acute care hospitals (6 university and 7 community teaching hospitals) from 1 November 2019 to 31 May 2021. Daily HH adherence was compared with daily COVID-19 case count across Ontario. During this period, weekly performance continued to be reported to units but unit-based quality improvement discussions were inconsistent due to the COVID-19 response.

Results

Figure 1 depicts daily aggregate HH adherence plotted against the new daily COVID-19 case count across Ontario. An elevation in HH adherence was seen prior to the start of the first wave, rising almost to 80% and then remained above 70% for the peak of wave one. During waves two and three, peak COVID-19 case counts were associated with a maximum HH adherence of 51%, only marginally above the pre-pandemic baseline. After the end of wave one (from 1 July 2020 to 31 May 2021) the median HH performance was only 49% (interquartile range 47%-50%).

Figure 1. Hand hygiene adherence across 13 acute care hospitals in comparison to overall new daily COVID-19 cases in Ontario

Conclusion

Initial improvements in HH adherence preceding the start of the COVID-19 pandemic were not sustained, possibly due to increasing comfort and reduced anxiety associated with providing care to COVID-19 patients leading to a perception of reduced COVID-19 transmission risk. These findings highlight the need for HH monitoring to be tied to longitudinal unit-led quality improvement in order to achieve durable changes in practice.

Disclosures

Susy S. Hota, MSc MD FRCPC, Finch Therapeutics (Research Grant or Support) Susy S. Hota, MSc MD FRCPC, Finch Therapeutics (Individual(s) Involved: Self): Grant/Research Support

Associations between plasma metabolite profiles and blood pressure: the HELIUS study

Background

Blood pressure (BP) is regulated by plasma metabolites from different neurohumoral and cardiometabolic systems. Since there are established differences in hypertension pathogenesis and treatment response between ethnicities, we hypothesized that plasma metabolites may be differently associated with BP across ethnic groups.

Purpose

To investigate associations between plasma metabolite profiles and BP in a multi-ethnic population-based cohort.

Methods

From the Healthy Living In an Urban Setting (HELIUS) study, 369 subjects (mean age 52±11 years, 51%F) of African and non-African descent were included. Office systolic (136±21 mmHg) and diastolic (83±12 mmHg) BP levels were recorded. Plasma metabolites were measured semi-quantitively with LC-MS (Metabolon) from fasting plasma samples. Associations between metabolite profiles and BP were assessed with machine learning prediction models using the XGBoost algorithm with nested cross-validation. Associations between the resulting best predictors and BP were assessed with linear regression models while adjusting for age, sex, estimated glomerular filtration rate and diabetes.

Results

Plasma metabolite profiles explained 14.1% of systolic BP variance and 10.6% of diastolic BP variance. These were attenuated to 3.1% and 1.4% respectively, when using residuals of BP after adjusting for age and sex. Top predictors for both systolic and diastolic BP included N-formylmethionine, several acylcarnitines and polyunsaturated fatty acids such as hexadecadienoate. These metabolites were significantly associated with higher systolic BP with estimates ranging from 3.0 to 4.5 mmHg per 1 SD increase in the adjusted models. Associations with hexadecadienoate, dihomolinoleate and catecholamine metabolites, including vanillactate had significant interactions (p&lt;0.05) with ethnicity, and were only significant in subjects of non-African descent.

Conclusions

Plasma metabolome composition explained a large proportion of BP variance, but this association was attenuated when adjusting for confounders. Polyunsaturated fatty acids and catecholamine metabolites were only associated with BP in the non-African descent subjects. N-formylmethionine was the most consistent predictor for systolic BP across all subgroups. Future studies could focus on translating these findings in vitro in order to decipher the role of N-formylmethionine in BP regulation.

Funding Acknowledgement

Type of funding sources: Public grant(s) – EU funding. Main funding source(s): Dutch Heart Foundation, the Netherlands Organization for Health Research and Development, the European Integration Fund and the European Union (Seventh Framework Programme) Explained variances of machine learningLinear regression models

The KSHV ORF20 Protein Interacts with the Viral Processivity Factor ORF59 and Promotes Viral Reactivation

Upon Kaposi's Sarcoma-associated herpesvirus (KSHV) lytic reactivation, rapid and widespread amplification of viral DNA (vDNA) triggers significant nuclear reorganization. As part of this striking shift in nuclear architecture, viral replication compartments are formed as sites of lytic vDNA production along with remarkable spatial remodeling and the relocalization of cellular and viral proteins. These viral replication compartments house several lytic gene products that coordinate viral gene expression, vDNA replication, and nucleocapsid assembly. The viral proteins and mechanisms that regulate this overhaul of the nuclear landscape during KSHV replication remain largely unknown. KSHV's ORF20 is a widely conserved lytic gene among all herpesviruses, suggesting it may have a fundamental contribution to the progression of herpesviral infection. Here, we utilized a promiscuous biotin ligase proximity labeling method to identify the proximal interactome of ORF20, which includes several replication-associated viral proteins, one of which is ORF59, the KSHV DNA processivity factor. Using coimmunoprecipitation and immunofluorescence assays, we confirmed the interaction between ORF20 and ORF59 and tracked the localization of both proteins to KSHV replication compartments. To further characterize the function of ORF20, we generated an ORF20-deficient KSHV and compared its replicative fitness to that of wild-type virus. Virion production was significantly diminished in the ORF20-deficient virus as observed by supernatant transfer assays. Additionally, we tied this defect in viable virion formation to a reduction in viral late gene expression. Lastly, we observed an overall reduction in vDNA replication in the ORF20-deficient virus, implying a key role for ORF20 in the regulation of lytic replication. Taken together, these results capture the essential role of KSHV ORF20 in progressing viral lytic infection by regulating vDNA replication alongside other crucial lytic proteins within KSHV replication compartments. IMPORTANCE Kaposi's Sarcoma-associated herpesvirus (KSHV) is a herpesvirus that induces lifelong infection, and as such, its lytic replication is carefully controlled to allow for efficient dissemination from its long-term reservoir and for the spread of the virus to new hosts. Viral DNA replication involves many host and viral proteins, coordinating both in time and space to successfully progress through the viral life cycle. Yet, this process is still not fully understood. We investigated the role of the poorly characterized viral protein ORF20, and through proximity labeling, we found that ORF20 interacts with ORF59 in replication compartments and affects DNA replication and subsequent steps of the late viral life cycle. Collectively, these results provide insights into the possible contribution of ORF20 to the complex lytic DNA replication process and suggest that this highly conserved protein may be an important modulator of this key viral mechanism.

Introduction of Group Electronic Monitoring of Hand Hygiene on Inpatient Units: A Multicenter Cluster Randomized Quality Improvement Study

BACKGROUND

The current approach to measuring hand hygiene (HH) relies on human auditors who capture <1% of HH opportunities and rapidly become recognized by staff, resulting in inflation in performance. Group electronic monitoring is a validated method of measuring HH adherence, but data demonstrating the clinical impact of this technology are lacking.

METHODS

A stepped-wedge cluster randomized quality improvement study was performed on 26 inpatient medical and surgical units across 5 acute care hospitals in Ontario, Canada. The intervention involved daily HH reporting as measured by group electronic monitoring to guide unit-led improvement strategies. The primary outcome was monthly HH adherence (percentage) between baseline and intervention. Secondary outcomes included transmission of antibiotic-resistant organisms such as methicillin-resistant Staphylococcus aureus (MRSA) and other healthcare-associated infections.

RESULTS

After adjusting for the correlation within inpatient units and hospitals, there was a significant overall improvement in HH adherence associated with the intervention (incidence rate ratio [IRR], 1.73 [95% confidence interval {CI}, 1.47-1.99]; P < .0001). Monthly HH adherence relative to the intervention increased from 29% (1 395 450/4 544 144) to 37% (598 035/1 536 643) within 1 month, followed by consecutive incremental increases up to 53% (804 108/1 515 537) by 10 months (P < .0001). There was a trend toward reduced healthcare-associated transmission of MRSA (IRR, 0.74 [95% CI, .53-1.04]; P = .08).

CONCLUSIONS

The introduction of a system for group electronic monitoring led to rapid, significant improvements in HH performance within a 2-year period. This method offers significant advantages over direct observation for measurement and improvement of HH.

Post-exposure prophylaxis against SARS-CoV-2 in close contacts of confirmed COVID-19 cases (CORIPREV): study protocol for a cluster-randomized trial

Background

Post-exposure prophylaxis (PEP) is a well-established strategy for the prevention of infectious diseases, in which recently exposed people take a short course of medication to prevent infection. The primary objective of the COVID-19 Ring-based Prevention Trial with lopinavir/ritonavir (CORIPREV-LR) is to evaluate the efficacy of a 14-day course of oral lopinavir/ritonavir as PEP against COVID-19 among individuals with a high-risk exposure to a confirmed case.

Methods

This is an open-label, multicenter, 1:1 cluster-randomized trial of LPV/r 800/200 mg twice daily for 14 days (intervention arm) versus no intervention (control arm), using an adaptive approach to sample size calculation. Participants will be individuals aged > 6 months with a high-risk exposure to a confirmed COVID-19 case within the past 7 days. A combination of remote and in-person study visits at days 1, 7, 14, 35, and 90 includes comprehensive epidemiological, clinical, microbiologic, and serologic sampling. The primary outcome is microbiologically confirmed COVID-19 infection within 14 days after exposure, defined as a positive respiratory tract specimen for SARS-CoV-2 by polymerase chain reaction. Secondary outcomes include safety, symptomatic COVID-19, seropositivity, hospitalization, respiratory failure requiring ventilator support, mortality, psychological impact, and health-related quality of life. Additional analyses will examine the impact of LPV/r on these outcomes in the subset of participants who test positive for SARS-CoV-2 at baseline. To detect a relative risk reduction of 40% with 80% power at α = 0.05, assuming the secondary attack rate in ring members (p₀) = 15%, 5 contacts per case and intra-class correlation coefficient (ICC) = 0.05, we require 110 clusters per arm, or 220 clusters overall and approximately 1220 enrollees after accounting for 10% loss-to-follow-up. We will modify the sample size target after 60 clusters, based on preliminary estimates of p₀, ICC, and cluster size and consider switching to an alternative drug after interim analyses and as new data emerges. The primary analysis will be a generalized linear mixed model with logit link to estimate the effect of LPV/r on the probability of infection. Participants who test positive at baseline will be excluded from the primary analysis but will be maintained for additional analyses to examine the impact of LPV/r on early treatment.

Discussion

Harnessing safe, existing drugs such as LPV/r as PEP could provide an important tool for control of the COVID-19 pandemic. Novel aspects of our design include the ring-based prevention approach, and the incorporation of remote strategies for conducting study visits and biospecimen collection.

Trial registration

This trial was registered at www.ClinicalTrials.gov (NCT04321174) on March 25, 2020.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13063-021-05134-7.

Monitoring of EGFR mutations in circulating tumor DNA of non-small cell lung cancer patients treated with EGFR inhibitors

PURPOSE

We studied EGFR mutations in circulating tumor DNA (ctDNA) and explored their role in predicting the progression-free survival (PFS) of non-small cell lung cancer (NSCLC) patients treated with erlotinib or gefitinib.

METHODS

The L858R, T790M mutations and exon 19 deletions were quantified in plasma using digital droplet polymerase chain reaction (ddPCR). The dynamics of ctDNA mutations over time and relationships with PFS were explored.

RESULTS

In total, 249 plasma samples (1-13 per patient) were available from 68 NSCLC patients. The T790M and L858R or exon 19 deletion were found in the ctDNA of 49 and 56% patients, respectively. The median (range) concentration in these samples were 7.3 (5.1-3688.7), 11.7 (5.1-12,393.3) and 27.9 (5.9-2896.7) copies/mL, respectively. Using local polynomial regression, the number of copies of EGFR mutations per mL increased several months prior to progression on standard response evaluation.

CONCLUSION

This change was more pronounced for the driver mutations than for the resistance mutations. In conclusion, quantification of EGFR mutations in plasma ctDNA was predictive of treatment outcomes in NSCLC patients. In particular, an increase in driver mutation copy number could predict disease progression.

Inferring pore radius and density from ultrasonic attenuation using physics-based modeling

This work proposes the use of two physics-based models for wave attenuation to infer the microstructure of cortical bone-like structures. One model for ultrasound attenuation in porous media is based on the independent scattering approximation (ISA) and the other model is based on the Waterman Truell (WT) approximation. The microstructural parameters of interest are pore radius and pore density. Attenuation data are simulated for three-dimensional structures mimicking cortical bone using the finite-difference time domain package SimSonic. These simulated structures have fixed sized pores (monodisperse), allowing fine-tuned control of the microstructural parameters. Structures with pore radii ranging from 50 to 100  μm and densities ranging from 20 to 50 pores/mm3 are generated in which only the attenuation due to scattering is considered. From here, an inverse problem is formulated and solved, calibrating the models to the simulated data and producing estimates of pore radius and density. The estimated microstructural parameters closely match the values used to simulate the data, validating the use of both the ISA and WT approximations to model ultrasonic wave attenuation in heterogeneous structures mimicking cortical bone. Furthermore, this illustrates the effectiveness of both models in inferring pore radius and density solely from ultrasonic attenuation data.

837. Contamination of Hospital Drains by Carbapenemase-Producing Enterobacterales (CPE) in Ontario, Canada

Background

The hospital water environment is a CPE reservoir, and transmission of CPE from drains to patients is a risk.

Methods

We cultured sink and shower drains in patient rooms and communal shower rooms that were exposed to inpatients with CPE colonization/infection from October 2007 to December 2017 at 10 hospitals. We compared patient room drain CPE to prior room occupant CPE using Illumina and MinION whole-genome sequencing.

Results

Three-hundred and ten inpatients exposed 1,209 drains, of which 53 (4%) yielded 62 CPE isolates at 7 (70%) hospitals. Compared to room occupant CPE isolates, drain CPE isolates were more likely Enterobacter spp. (6, 10% vs. 25, 51%, p< 0.0001) or KPC-producers (9, 15% vs. 23, 47%, p=0.0002). Of the 49 CPE isolates in patient room drains, 4 (8%) were linked to a prior room occupant (Table), 24 (49%) had the same carbapenemase as a prior room occupant but isolates/carbapenemase gene-containing plasmids that were unrelated, and 21 (43%) did not share a carbapenemase with a prior room occupant. The 4 drains linked to prior room occupants were likely contaminated by these room occupants, who were CPE-colonized prior to drain exposure. Despite few links between drain and room occupant CPE, there were 10 isolates harbouring related bla_NDM-1-containing IncHI2A/HI2-type plasmids in 8 rooms on two units at one hospital. Nine of these were Enterobacter hormaechei ST66 isolates that were 0 to 6 SNVs apart and one was a Klebsiella oxytoca STnovel isolate.

Table. Four patient room drain CPE isolates (D1b, D4, D5, D12) and isolates from prior room occupants that they were related to by whole-genome sequencing.

Conclusion

It was uncommon for drain CPE to be linked to prior patient exposure. This suggests contamination of most drains by undetected colonized patients and a need for more aggressive patient screening in our hospitals. This may also suggest retrograde (drain-to-drain) transmission, especially considering the 10 isolate drain cluster at one hospital. Reasons for the preponderance of Enterobacter spp. in drains requires further study.

Disclosures

Allison McGeer, MD, FRCPC, GlaxoSmithKline (Advisor or Review Panel member, Research Grant or Support)Merck (Advisor or Review Panel member, Research Grant or Support)Pfizer (Research Grant or Support)

[Delirium in the elderly; article for education and training purposes]

In delirium, there is an acute change of consciousness with fluctuations in attention, cognition and perception. Delirium can be provoked by medical conditions, or the use or withdrawal of drugs. Risk factors include older age and cognitive impairment. Delirium is associated with many complications, represents a significant emotional burden for the patient and caretakers, increases length of stay in the hospital, and causes higher health care costs. Non-pharmacological measurements can sometimes prevent delirium, and are essential for its treatment with proven effectiveness. Antipsychotics should be administered only as an exception, not as a rule. Antipsychotics may be of use when the patient puts himself or others in danger, or when he suffers substantially from hallucinations.

Associations between gut microbiome, short chain fatty acids and blood pressure across ethnic groups: the HELIUS study

Background

Gut microbiome composition is shaped by a combination of host genetic make-up and dietary habits. In addition, large ethnic differences exist in microbiome composition. Several studies in humans and animals have shown that differences in gut microbiota and its metabolites, including short chain fatty acids (SCFA), are associated with blood pressure (BP). We hypothesized that gut microbiome composition and its metabolites may be differently associated with BP across ethnic groups.

Purpose

To investigate associations of gut microbiome composition and fecal SCFA levels with BP across different ethnic groups.

Methods

We assessed the association between gut microbiome composition and office BP among 4672 subjects (mean age 49.8±11.7 years, 52%F) of 6 different ethnic groups participating in the HELIUS study. Gut microbiome composition was determined using 16S rRNA sequencing. Associations between microbiome composition and blood pressure were assessed using machine learning prediction models. The resulting best predictors were correlated with BP using Spearman's rank correlations. Fecal SCFA levels were measured with high-performance liquid chromatography in an age- and body mass index (BMI)-matched subgroup of 200 participants with either extreme low or high systolic BP. Differences in abundances of best predictors and fecal SCFA levels between high and low BP groups were assessed with Mann-Whitney U tests.

Results

Gut microbiome composition explained 4.4% of systolic BP variance. Best predictors for systolic BP included Roseburia spp. (ρ −0.15, p&lt;0.001), Clostridium spp. (ρ −0.14, p&lt;0.001), Romboutsia spp. (ρ −0.10, p&lt;0.001), and Ruminococceae spp. (ρ −0.15, p&lt;0.001) (Figure 1). Explained variance of the microbiome composition was highest in Dutch subjects (4.8%), but very low in African Surinamese, Ghanaian, and Turkish ethnic groups (ranging from 0–0.77%) Hence, we selected only participants with Dutch ethnicity for the matched subgroup. Participants with high BP had lower abundance of Roseburia hominis (p&lt;0.01) and Roseburia spp. (p&lt;0.05) compared to participants with low BP. However, fecal acetate (p&lt;0.05) and propionate (p&lt;0.01) levels were higher in participants with high BP.

Conclusions

In this cross-sectional study, gut microbiome composition was moderately associated with BP. Associations were strongly divergent between ethnic groups, with strongest associations in Dutch participants. Intriguingly, while Dutch participants with high BP had lower abundances of several SCFA-producing microbes, they had higher fecal SCFA levels. Intervention studies with SCFAs could provide more insight in the effects of these metabolites on BP.

Funding Acknowledgement

Type of funding source: Public Institution(s). Main funding source(s): The Academic Medical Center (AMC) of Amsterdam and the Public Health Service of Amsterdam (GGD Amsterdam) provided core financial support for HELIUS. The HELIUS study is also funded by research grants of the Dutch Heart Foundation (Hartstichting; grant no. 2010T084), the Netherlands Organization for Health Research and Development (ZonMw; grant no. 200500003), the European Integration Fund (EIF; grant no. 2013EIF013) and the European Union (Seventh Framework Programme, FP-7; grant no. 278901).

In vitro differential responses of rat and human aryl hydrocarbon receptor to two distinct ligands and to different polyphenols

TCDD (2,3,7,8-tetrachlorodibenzo-p-dioxin) and several other environment/food-borne toxic compounds induce their toxicity via the aryl hydrocarbon receptor (AhR). AhR is also modulated by various endogenous ligands e.g. highly potent tryptophan (Trp)-derivative FICZ (6-formylindolo[3,2-b]carbazole) and natural ligands abundant in the human diet e.g. polyphenols. Therefore, evaluating AhR species-specific responses is crucial for understanding AhR physiological functions, establishing risk assessments, and exploring the applicability of AhR mediators in drug and food industry towards human-based usages. We studied AhR transactivation of FICZ/TCDD in vitro in a time-dependent and species-specific manner using dioxin responsive luciferase reporter gene assays derived from rat (DR-H4IIE) and human (DR-HepG2) hepatoma cells. We observed for the first time that FICZ potency was similar in both cell lines and was 40 times higher than TCDD in DR-HepG2 cells. Depleting Trp-derivative endogenously produced ligands by using culture medium without Trp, resulted in 3-fold higher AhR activation upon adding FICZ in DR-H4IIE cells, in contrast to DR-HepG2 cells which revealed a fast degradation of FICZ induction from 10 h post-exposure to complete disappearance after 24 h. Seven polyphenols and a mixture thereof, chosen based on commercially recommended doses and adjusted to human realistic exposure, caused rat and human species-specific AhR responses. Two isoflavones (daidzein and genistein) induced rat AhR synergistic effects with FICZ and/or TCDD, while quercetin, chrysin, curcumin, resveratrol, and the mixture exerted a strong inhibitory effect on the human AhR. Strikingly, resveratrol and quercetin at their realistic nanomolar concentrations acted additively in the mixture to abolish human AhR activation induced by various TCDD concentrations. Taken together, these results illustrate the species-specific complexity of AhR transcriptional activities modulated by various ligands and highlight the need for studies of human-based approaches.

How to promote physical activity during pregnancy : A systematic review

INTRODUCTION

Sedentary lifestyles and physical inactivity have been shown to increase during pregnancy and are a cause of obstetric comorbidity. The objective of this study was to conduct a systematic review of interventions aiming to promote physical activity during pregnancy.

MATERIAL AND METHODS

Databases were searched from January 2008 to September 2019. Selection criteria included randomized controlled trials evaluating the efficacy of interventions promoting physical activity during pregnancy.

RESULTS

In total, 256 articles were extracted from databases. 202 articles were excluded. Finally, 15 articles were included in the study. 5633 patients were included from various populations. Six studies rated physical activity (PA) as the primary outcome. Five studies suggested promoting physical activity through individual interviews which in two studies showed an increase in PA. Three studies evaluated an intervention based on group interviews and one of these reported a significant increase in PA. Two studies evaluated the use of a Smartphone application to promote physical activity but they did not conclude that they were effective because they were designed with low statistical power.

CONCLUSION

The practice of regular PA during pregnancy reduces obstetrical comorbidity. However, interventions seem to have a low impact on the promotion of PA during pregnancy. New intervention strategies need to assessed, such as the use of mobile health interventions.

Estimated surge in hospital and intensive care admission because of the coronavirus disease 2019 pandemic in the Greater Toronto Area, Canada: a mathematical modelling study

BACKGROUND

In pandemics, local hospitals need to anticipate a surge in health care needs. We examined the modelled surge because of the coronavirus disease 2019 (COVID-19) pandemic that was used to inform the early hospital-level response against cases as they transpired.

METHODS

To estimate hospital-level surge in March and April 2020, we simulated a range of scenarios of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spread in the Greater Toronto Area (GTA), Canada, using the best available data at the time. We applied outputs to hospital-specific data to estimate surge over 6 weeks at 2 hospitals (St. Michael's Hospital and St. Joseph's Health Centre). We examined multiple scenarios, wherein the default (R0 = 2.4) resembled the early trajectory (to Mar. 25, 2020), and compared the default model projections with observed COVID-19 admissions in each hospital from Mar. 25 to May 6, 2020.

RESULTS

For the hospitals to remain below non-ICU bed capacity, the default pessimistic scenario required a reduction in non-COVID-19 inpatient care by 38% and 28%, respectively, with St. Michael's Hospital requiring 40 new ICU beds and St. Joseph's Health Centre reducing its ICU beds for non-COVID-19 care by 6%. The absolute difference between default-projected and observed census of inpatients with COVID-19 at each hospital was less than 20 from Mar. 25 to Apr. 11; projected and observed cases diverged widely thereafter. Uncertainty in local epidemiological features was more influential than uncertainty in clinical severity.

INTERPRETATION

Scenario-based analyses were reliable in estimating short-term cases, but would require frequent re-analyses. Distribution of the city's surge was expected to vary across hospitals, and community-level strategies were key to mitigating each hospital's surge.

Revealing the Microscopic Structure of Human Renal Cell Carcinoma in Three Dimensions

For fully characterizing renal cell carcinoma (RCC), information about the 3D tissue microstructure is essential. Histopathology, which represents the current diagnostic gold standard, is destructive and only provides 2D information. 3D X-ray histology endeavors to overcome these limitations by generating 3D data. In a laboratory environment, most techniques struggle with limited resolution and the weak X-ray attenuation contrast of soft tissue. We recently developed a laboratory-based method combining nanoscopic X-ray CT with a cytoplasm-specific X-ray stain. Here, we present the application of this method to human RCC biopsies. The NanoCT slices enable pathological characterization of crucial structures by reproducing tissue morphology with a similar detail level as corresponding histological light microscopy images. Beyond that, our data offer deeper insights into the 3D configuration of the tumor. By demonstrating the compatibility of the X-ray stain with standard pathological stains, we highlight the feasibility of integrating staining based NanoCT into the pathological routine.

Elucidating the aryl hydrocarbon receptor antagonism from a chemical-structural perspective

The aryl hydrocarbon receptor (AhR) plays an important role in several biological processes such as reproduction, immunity and homoeostasis. However, little is known on the chemical-structural and physicochemical features that influence the activity of AhR antagonistic modulators. In the present report, in vitro AhR antagonistic activity evaluations, based on a chemical-activated luciferase gene expression (AhR-CALUX) bioassay, and an extensive literature review were performed with the aim of constructing a structurally diverse database of contaminants and potentially toxic chemicals. Subsequently, QSAR models based on Linear Discriminant Analysis and Logistic Regression, as well as two toxicophoric hypotheses were proposed to model the AhR antagonistic activity of the built dataset. The QSAR models were rigorously validated yielding satisfactory performance for all classification parameters. Likewise, the toxicophoric hypotheses were validated using a diverse set of 350 decoys, demonstrating adequate robustness and predictive power. Chemical interpretations of both the QSAR and toxicophoric models suggested that hydrophobic constraints, the presence of aromatic rings and electron-acceptor moieties are critical for the AhR antagonism. Therefore, it is hoped that the deductions obtained in the present study will contribute to elucidate further on the structural and physicochemical factors influencing the AhR antagonistic activity of chemical compounds.

418 Ultrasound molecular imaging of the role of von willebrand factor-mediated platelet adhesion in atherogenesis

Funding Acknowledgements

JSPS Overseas Research Fellowship

Background

Platelets are known to be both pro-inflammatory and pro-mitogenic. However, the role of platelet-endothelial interactions in the initiation and growth of atherosclerotic lesions is not well understood.

Purpose

We used contrast-enhanced ultrasound (CEU) molecular imaging of the arterial endothelium to test the hypothesis that platelet attachment to endothelial Von Willebrand Factor (VWF) promotes atherogenesis.

Methods

We studied wild-type mice (WT), low-density lipoprotein deficient mice fed western diet to produce atherosclerosis (LDLR-/-), and LDLR-/- mice also deficient for ADAMTS-13 (LDLR-/-ADAMTS13-/-) which is the enzyme responsible for proteolytic cleavage of endothelial-associated VWF. Mice were studied at 20 weeks and 30 weeks of age. A subset of LDLR-/- mice were treated with recombinant ADAMTS13 1 hr prior to study. Proximal aortic CEU molecular imaging of P-selectin, vascular cell adhesion molecule (VCAM)-1, von Willebrand factor (VWF), and platelet GPIbα was performed. Aortic distensibility was assessed using high-frequency (30 MHz) transthoracic echocardiography and tail cuff blood pressure systems. NF-κB of aorta was assessed by ELISA kit. Plaque size and composition were assessed by histology. Platelets and macrophage immunohistochemistry were also performed on confocal microscopy.

Results

Aortic molecular imaging signal for P-selectin, VCAM-1, VWF, and platelet adhesion was significantly higher in LDLR-/- than WT mice, and increased by 2-fold between 20 and 30 wks of age. Signal for VWF and platelet adhesion was abolished 1 h after administration of ADAMTS13, confirming that platelet adhesion was VWF-mediated. At 20 and 30 wks of age, molecular imaging signal for all targets was 2-fold higher (p &lt; 0.01) in LDLR-/-ADAMTS13-/- versus LDLR-/- mice. The LDLR-/-ADAMTS13-/- mice also had lower aortic distensibility (p &lt; 0.05), had a 2-fold higher NF-κB signal (p &lt; 0.05), and had a 2-fold greater total plaque area (p &lt; 0.01). Fluorescent immunohistochemistry confirmed that the LDLR-/-ADAMTS13-/- mice also had greater platelets (p &lt; 0.05) and increased macrophage content (p &lt; 0.05) than LDLR-/- mice in aortic plaque.

Conclusion

In early to mid-stage atherosclerosis, abnormal regulation of endothelial-associated VWF results in platelet adhesion and secondary up-regulation of endothelial inflammatory adhesion molecules, thereby promoting atherosclerotic plaque progression. These results indicate an important role of platelet-endothelial interactions in early atherogenesis.

Abstract 418 Figure

Burkholderia cenocepacia ET12 transmission in adults with cystic fibrosis

This report describes transmission of a Burkholderia cenocepacia ET12 strain (ET12-Bc) at the Toronto Adult Cystic Fibrosis (CF) Centre occurring from 2008 to 2017. Epidemiological and genomic data from 11 patients with CF were evaluated. Isolates were analysed using whole genome sequencing (WGS). Epidemiological investigation and WGS analysis suggested nosocomial transmission, despite enhanced infection control precautions. This was associated with subsequent deaths in 10 patients. ET12-Bc positive patients are no longer cared for on the same unit as ET12-Bc negative patients.

A mixture of persistent organic pollutants relevant for human exposure inhibits the transactivation activity of the aryl hydrocarbon receptor in vitro

While humans are exposed to mixtures of persistent organic pollutants (POPs), their risk assessment is usually based on a chemical-by-chemical approach. To assess the health effects associated with mixed exposures, knowledge on mixture toxicity is required. Several POPs are potential ligands of the Aryl hydrocarbon receptor (AhR), which involves in xenobiotic metabolism and controls many biological pathways. This study assesses AhR agonistic and antagonistic activities of 29 POPs individually and in mixtures by using Chemical-Activated LUciferase gene eXpression bioassays with 3 transgenic cell lines (rat hepatoma DR-H4IIE, human hepatoma DR-Hep G2 and human mammary gland carcinoma DR-T47-D). Among the 29 POPs, which were selected based on their abundance in Scandinavian human blood, only 4 exerted AhR agonistic activities, while 16 were AhR antagonists in DR-H4IIE, 5 in DR-Hep G2 and 7 in DR-T47-D when tested individually. The total POP mixture revealed to be AhR antagonistic. It antagonized EC₅₀ TCDD inducing AhR transactivation at a concentration of 125 and 250 and 500 fold blood levels in DR-H4IIE, DR-T47-D and DR-Hep G2, respectively, although each compound was present at these concentrations lower than their LOEC values. Such values could occur in real-life in food contamination incidents or in exposed populations. In DR-H4IIE, the antagonism of the total POP mixture was due to chlorinated compounds and, in particular, to PCB-118 and PCB-138 which caused 90% of the antagonistic activity in the POP mixture. The 16 active AhR antagonists acted additively. Their mixed effect was predicted successfully by concentration addition or generalized concentration addition models, rather than independent action, with only two-fold IC₅₀ underestimation. We also attained good predictions for the full dose-response curve of the antagonistic activity of the total POP mixture.

Human blood-based exposure levels of persistent organic pollutant (POP) mixtures antagonise androgen receptor transactivation and translocation

INTRODUCTION

Human exposure to persistent organic pollutants (POPs) has been linked to genitourinary health-related conditions such as decreased sperm quality, hypospadias, and prostate cancer (PCa). Conventional risk assessment of POPs focuses on individual compounds. However, in real life, individuals are exposed to many compounds simultaneously. This might lead to combinatorial effects whereby the global effect of the mixture is different from the effect of the single elements or subgroups. POP mixtures may act as endocrine disruptors via the androgen receptor (AR) and potentially contribute to PCa development.

AIM

To determine the endocrine disrupting activity of a POP mixture and sub-mixtures based upon exposure levels detected in a human Scandinavian population, on AR transactivation and translocation in vitro.

MATERIALS AND METHODS

The Total POP mixture combined 29 chemicals modelled on the exposure profile of a Scandinavian population and 6 sub-mixtures: brominated (Br), chlorinated (Cl), Cl + Br, perfluorinated (PFAA), PFAA + Br, PFAA + Cl, ranging from 1/10× to 500× relative to what is found in human blood. Transactivation was measured by reporter gene assay (RGA) and translocation activity was measured by high content analysis (HCA), each using stably transfected AR model cell lines.

RESULTS

No agonist activity in terms of transactivation and translocation was detected for any POP mixtures. In the presence of testosterone the Cl + Br mixture at 100× and 500× blood level antagonised AR transactivation, whereas the PFAA mixture at blood level increased AR transactivation (P < 0.05). In the presence of testosterone the Cl and PFAA + Br mixtures at 1/10×, 1×, and 50× blood level antagonised AR translocation (P < 0.05).

CONCLUSION

Taken together, some combinations of POP mixtures can interfere with AR translocation. However, in the transactivation assay, these combinations did not affect gene transactivation. Other POP combinations were identified here as modulators of AR-induced gene transactivation without affecting AR translocation. Thus, to fully evaluate the effect of environmental toxins on AR signalling, both types of assays need to be applied.

Evaluation of Matrix-Assisted Laser Desorption Ionization Time-of-Flight Mass Spectrometry and ClinPro Tools as a Rapid Tool for Typing Streptococcus pyogenes

Background

Timely strain typing of group A Streptococci (GAS) is necessary to guide outbreak recognition and investigation. We evaluated the use of (matrix-assisted laser desorption ionization time-of-flight mass spectrometry) combined with cluster analysis software to rapidly distinguish between related and unrelated GAS isolates in real-time.

Methods

We developed and validated a typing model using 177 GAS isolates with known emm types. The typing model was created using 43 isolates, which included 8 different emm types, and then validated using 134 GAS isolates of known emm types that were not included in model generation.

Results

Twelve spectra were generated from each isolate during validation. The overall accuracy of the model was 74% at a cutoff value of 80%. The model performed well with emm types 4, 59, and 74 but showed poor accuracy for emm types 1, 3, 12, 28, and 101. To evaluate the ability of this tool to perform typing in an outbreak situation, we evaluated a virtual outbreak model using a “virtual outbreak strain; emm74” compared with a non-outbreak group or an “outgroup “ of other emm types. External validation of this model showed an accuracy of 91.4%.

Conclusions

This approach has the potential to provide meaningful information that can be used in real time to identify and manage GAS outbreaks. Choosing isolates characterized by whole genome sequencing rather than emm typing for model generation should improve the accuracy of this approach in rapidly identifying related and unrelated GAS strains.

Development of chemical-based reference standards for rooibos and honeybush aroma lexicons

The honeybush sensory wheel was revised, using a large sample set (n = 585) comprising of the major commercial Cyclopia species, i.e. C. intermedia, C. subternata and C. genistoides. Only positive and negative aroma attributes were included in the wheel. Chemicals were identified to serve as reference standards for the honeybush (Cyclopia spp.) lexicon. Similarly, chemical-based reference standards were identified for the rooibos (Aspalathus linearis) lexicon. From a comprehensive literature search and gas chromatography-mass spectrometry analyses, chemicals were screened by an expert panel for their suitability in terms of typicality of the target aroma. Each chemical was evaluated in a 'base tea' and compared to a specific 'reference tea' exhibiting a high intensity of the target aroma. A total of 30 and 44 chemicals for rooibos and honeybush, respectively, were selected for validation by a trained panel. Descriptive sensory analysis was conducted to assign typicality and intensity scores for each chemical representing a target aroma attribute. Several chemicals were identified as suitable reference standards for the following aroma notes: isophorone ('rooibos-woody'), maltyl isobutyrate ('caramel'), cis-3-hexenol ('green grass'), 4-oxoisophorone ('seaweed') and 2,4,6-trichloroanisole ('musty/mouldy') for rooibos; and 2-acetyl-5-methylfuran ('woody'), levulinic acid ('fynbos-sweet'), maltyl isobutyrate ('caramel'), and 2-acetylpyrrole ('nutty') for honeybush.

P4515The aging heart failure patient: frailty and cognitive impairment more common than you would expect - baseline data of the heart-brain clinic

Background

Heart failure (HF) is a cardiovascular disease that is increasing by epidemic proportions, largely due to an aging society and therapeutic advances in disease management. Because heart failure is largely a cardiogeriatric syndrome, age-related syndromes such as frailty and cognitive impairment are common in heart failure patients.

Purpose

To assess the prevalence and determinants of frailty and cognitive impairment in a HF population ≥60 years of age.

Methods

Data from n=236 patients with HF (77±9 years; 43% female) visiting the heart-brain clinic in Amsterdam in 2018–2019. HF severity was evaluated by NT-proBNP and NYHA-classification. Frailty was assessed using Fried's frailty criteria, cognition using the Montreal cognitive assessment (MoCa). Logistic regression analyses were performed to evaluate which variables were associated with frailty and cognitive impairment.

Results

Median (IQR) NT-proBNP was 2000 (876–3469) pmol/L, 38% of patients had NYHA III-IV. 51% of patients were pre-frail and 28% frail. 77% of the patients were (mildly) cognitive impaired. Age, NYHA-classification III-IV, NT-proBNP>2000 pmol/L and use of ≥10 drugs were associated with frailty; HR (95% CI): 2.0 (1.4–3.0) per 10 years, 3.4 (1.9–6.2), 1.8 (1.0–3.2) and 1.8 (1.4–3.3) respectively. Age was associated with cognitive impairment; HR (95% CI) 2.2 (1.4–3.6) per 10 years.

Figure 1

Conclusion(s)

Frailty affects almost a third of the patients with HF and is more prevalent in older patients and those with more severe HF. Screening for frailty and cognitive impairment should be part of the standard workup in older HF patients as frail and/or cognitively impaired HF patients are less likely to adhere to their HF treatment and more likely to be (re)admitted to hospital for HF.

Prediction of response to anti-PD-1 therapy in patients with non-small-cell lung cancer by electronic nose analysis of exhaled breath

BACKGROUND

Immune checkpoint inhibitors have improved survival outcome of advanced non-small-cell lung cancer (NSCLC). However, most patients do not benefit. Therefore, biomarkers are needed that accurately predict response. We hypothesized that molecular profiling of exhaled air may capture the inflammatory milieu related to the individual responsiveness to anti-programmed death ligand 1 (PD-1) therapy. This study aimed to determine the accuracy of exhaled breath analysis at baseline for assessing nonresponders versus responders to anti-PD-1 therapy in NSCLC patients.

METHODS

This was a prospective observational study in patients receiving checkpoint inhibitor therapy using both a training and validation set of NSCLC patients. At baseline, breath profiles were collected in duplicate by a metal oxide semiconductor electronic nose (eNose) positioned at the rear end of a pneumotachograph. Patients received nivolumab or pembrolizumab of which the efficacy was assessed by Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1 at 3-month follow-up. Data analysis involved advanced signal-processing and statistics based on independent t-tests followed by linear discriminant and receiver operating characteristic (ROC) analysis.

RESULTS

Exhaled breath data of 143 NSCLC patients (training: 92, validation: 51) were available at baseline. ENose sensors contributed significantly (P < 0.05) at baseline in differentiating between patients with different responses at 3 months of anti-PD-1 treatment. The eNose sensors were combined into a single biomarker with an ROC-area under the curve (AUC) of 0.89 [confidence interval (CI) 0.82-0.96]. This AUC was confirmed in the validation set: 0.85 (CI 0.75-0.96).

CONCLUSION

ENose assessment was effective in the noninvasive prediction of individual patient responses to immunotherapy. The predictive accuracy and efficacy of the eNose for discrimination of immunotherapy responder types were replicated in an independent validation set op patients. This finding can potentially avoid application of ineffective treatment in identified probable nonresponders.

Augmentation of Tissue Perfusion in Patients With Peripheral Artery Disease Using Microbubble Cavitation

OBJECTIVES

The authors investigated ideal acoustic conditions on a clinical scanner custom-programmed for ultrasound (US) cavitation-mediated flow augmentation in preclinical models. We then applied these conditions in a first-in-human study to test the hypothesis that contrast US can increase limb perfusion in normal subjects and patients with peripheral artery disease (PAD).

BACKGROUND

US-induced cavitation of microbubble contrast agents augments tissue perfusion by convective shear and secondary purinergic signaling that mediates release of endogenous vasodilators.

METHODS

In mice, unilateral exposure of the proximal hindlimb to therapeutic US (1.3 MHz, mechanical index 1.3) was performed for 10 min after intravenous injection of lipid microbubbles. US varied according to line density (17, 37, 65 lines) and pulse duration. Microvascular perfusion was evaluated by US perfusion imaging, and in vivo adenosine triphosphate (ATP) release was assessed using in vivo optical imaging. Optimal parameters were then used in healthy volunteers and patients with PAD where calf US alone or in combination with intravenous microbubble contrast infusion was performed for 10 min.

RESULTS

In mice, flow was augmented in the US-exposed limb for all acoustic conditions. Only at the lowest line density was there a stepwise increase in perfusion for longer (40-cycle) versus shorter (5-cycle) pulse duration. For higher line densities, blood flow consistently increased by 3-fold to 4-fold in the US-exposed limb irrespective of pulse duration. High line density and long pulse duration resulted in the greatest release of ATP in the cavitation zone. Application of these optimized conditions in humans together with intravenous contrast increased calf muscle blood flow by >2-fold in both healthy subjects and patients with PAD, whereas US alone had no effect.

CONCLUSIONS

US of microbubbles when using optimized acoustic environments can increase perfusion in limb skeletal muscle, raising the possibility of a therapy for patients with PAD. (Augmentation of Limb Perfusion With Contrast Ultrasound; NCT03195556).

Prescription patterns of lipid lowering agents among older patients in general practice: an analysis from a national database in the Netherlands

BACKGROUND

Dutch cardiovascular risk management guidelines state almost every older adult (≥70 years) is eligible for a lipid lowering drug (LLD). However, life expectancy, frailty or comorbidities may influence this treatment decision.

OBJECTIVE

investigate how many older adults, according to age, frailty (Drubbel-frailty index) and comorbidities were prescribed LLDs.

METHODS

data of 244,328 adults ≥70 years from electronic health records of 415 Dutch general practices from 2011-15 were used. Number of LLD prescriptions in patients with (n = 55,309) and without (n = 189,019) cardiovascular disease (CVD) was evaluated according to age, frailty and comorbidities.

RESULTS

about 69% of adults ≥70 years with CVD and 36% without CVD were prescribed a LLD. LLD prescriptions decreased with age; with CVD: 78% aged 70-74 years and 29% aged ≥90 years were prescribed a LLD, without CVD: 37% aged 70-74 years and 12% aged ≥90 years. In patients with CVD and within each age group, percentage of LLD prescriptions was 20% point(pp) higher in frail compared with non-frail. In patients without CVD, percentage of LLD prescriptions in frail patients was 11pp higher in adults aged 70-74 years and 40pp higher in adults aged ≥90 years compared to non-frail. Similar trends were seen in the analyses with number of comorbidities.

CONCLUSION

in an older population, LLD prescriptions decreased with age but-contrary to our expectations-LLD prescriptions increased with higher frailty levels.

Limb Perfusion During Exercise Assessed by Contrast Ultrasound Varies According to Symptom Severity in Patients with Peripheral Artery Disease

BACKGROUND

In patients with peripheral artery disease (PAD), the severity of symptoms correlates poorly with ankle-brachial index (ABI). The aim of this study was to test the hypothesis that limb perfusion assessed using contrast-enhanced ultrasound (CEU) during contractile exercise varies according to functional class in patients with PAD, particularly those with ABIs in the 0.4 to 0.6 range whose symptoms vary widely.

METHODS

Bilateral quantitative CEU perfusion imaging of the calf was performed in normal control subjects (n = 10) and patients with PAD who had at least one limb with a moderately reduced ABI (0.4-0.6; n = 17). Imaging was performed at rest and immediately after 30 sec of modest periodic (0.3-Hz) plantar flexion (10 W).

RESULTS

In patients with PAD, Rutherford symptom classification for each limb varied widely, including in limbs with ABIs of 0.4 to 0.6 (n = 6 with mild or no symptoms, n = 14 with moderate to severe symptoms). CEU perfusion imaging parameters at rest were similar between control subjects and patients with PAD irrespective of ABI. In normal control subjects, limb flow increased on average by > 20-fold after only 30 sec of moderate exercise. In patients with PAD, muscle exercise perfusion for all limbs was reduced compared with control subjects and decreased according to the severity of ABI reduction, primarily from reduced microvascular flux rate. Even limbs with ABIs > 0.9 in patients with PAD had lower exercise perfusion than in control subjects (P = .03). In subjects with PAD, exercise perfusion was lower in those with moderate to severe versus mild symptoms when analyzed for all limbs (median, 30 IU/sec [interquartile range (IQR), 21-52 IU/sec] vs 84 IU/sec [IQR, 36-177 IU/sec]; P = .01) and limbs with ABIs of 0.4 to 0.6 (median, 26 IU/sec [IQR, 14-41 IU/sec] vs 54 IU/sec [IQR, 31-105 IU/sec]; P = .05).

CONCLUSIONS

In patients with PAD, CEU exercise perfusion imaging detects differences in limb muscle perfusion that are likely to be responsible for differences in symptom severity and can detect the flow abnormalities from microvascular dysfunction even in limbs with normal ABIs.