Correspondence - Further reflections of the role of artificial intelligence in acute medicine

We read with great interest the article "Artificial Intelligence: its Future and Impact on Acute Medicine". Regarding the historical perspective on artificial intelligence (AI) origins, we believe the role of John von Neumann (1903-1957) also deserves emphasis.

OP0068 DISTINCT STROMAL AND IMMUNE CELL INTERACTIONS SHAPE THE PATHOGENESIS OF RHEUMATOID AND PSORIATIC ARTHRITIS

Background

Rheumatoid (RA) and psoriatic arthritis (PsA) are common autoimmune and autoinflammatory diseases of unknown aetiology characterised by complex synovial pathology with a detrimental effect on the patient’s quality of life. Significant differences in pathophysiology may explain distinct clinical manifestations and account for differential responses to specific therapeutics. Recent implementation of single cell transcriptomic analysis of sorted synovial cells has revealed the diverse cellular landscape of the RA synovial stromal and immune cell compartments, however, a complete analysis of immune and stromal cells in tandem, for RA and PsA patient synovial tissue has not been performed.

Objectives

To combine novel scRNA transcriptomic approaches and ex vivo assays in order to: identify differences in the cellular landscape of RA and PsA synovial tissue inflammation and immune – stromal cell interactions that drive pathology in RA and PsA.

Methods

Single cell transcriptomic profiling of 178,000 synovial tissue cells from 5 PsA and 4 RA patients, importantly, without prior sorting of immune and stromal cells. This approach enabled the generation of a unique cell atlas of intact synovial tissue identifying immune and stromal cell interactions. State of the art data integration and annotation techniques identified and characterised 18 stromal and 14 immune cell clusters. Bioinformatic examination of cell-cell communication via construction of receptor-ligand interaction networks with further in vitro validation of stromal and immune cell crosstalk through flow cytometric analysis, multiplex ELISA and mitochondrial and single cell metabolic profiling by multiphoton and florescent lifetime imaging microscopy, seahorse.

Results

Following quality control and data integration the PsA and RA cellular landscape was generated and nine mega clusters indicative of fibroblasts, endothelial cells, pericytes, macrophages, dendritic cells (DC), B cells, plasma cells, T cells and NKT consisting of several sub clusters were identified. Distinct points of transcriptomic deviation and convergence between RA and PsA were identified for each of the major cell types of the joint. Specifically, cell cycle and trajectory analysis revealed that only a fraction of synovial T cells are actively proliferating. Additionally, the differential usage of immunoglobulin light chains by memory and plasma cells indicates that plasma cells are potentially not derived from the local memory B cell pool of the synovial tissue. Importantly, we report distinct fibroblast and endothelial cell transcriptomes indicating differentially abundant subpopulations in RA and PsA characterised by distinct transcription factor usage and signalling pathway enrichment. Specifically transcriptomic imputation analysis revealed abundance of invasive FAPα+THY1+ regulated by transcription factor TEAD1 in RA compared to PsA synovial tissue. In order to identify potential cell-cell communication driving inflammation in RA and PsA, novel receptor–ligand interaction networks were generated and downstream of the receptor, target characterisation was performed. Herein we identify RA-specific synovial T cell-derived TGF-β and macrophage IL-1β synergy in driving the transcriptional profile of FAPα+THY1+ invasive synovial-fibroblasts, expanded in RA compared to PsA synovial tissue biopsies (Figure 1). Ex vivo treatment of RA patient synovial fibroblasts identified TGF-b and IL-1b synergy are a major driver of IL-6 production, fibroblast activation and adhesion molecule expression. Interestingly, the aforementioned proinflammatory changes of RA patient synovial fibroblasts were coupled with significant alterations in mitochondrial eccentricity and size and a marked metabolic adaptation towards a strongly glycolytic profile (Figure 1).

Figure 1.

Conclusion

Disrupting specific immune and stromal cell interactions offers novel opportunities for targeted therapeutic intervention in RA and PsA.

Disclosure of Interests

Achilleas Floudas: None declared, Conor Smith: None declared, Orla Tynan: None declared, Nuno Neto: None declared, Vinod Krishna Employee of: Janssen Pharmaceuticals, Sarah Wade: None declared, Megan Hanlon: None declared, Clare Cunningham: None declared, Viviana Marzaioli: None declared, Mary Canavan: None declared, Jean Fletcher: None declared, Suzanne Cole Employee of: Janssen Pharmaceuticals, Ling-Yang Hao Employee of: Janssen Pharmaceuticals, Sunil Nagpal Employee of: Janssen Pharmaceuticals, GSK, Michael Monaghan: None declared, Douglas Veale Consultant of: Janssen, Eli Lilly, Pfizer, Ursula Fearon Consultant of: Janssen, Eli Lilly, Pfizer.

POS0443 INSIDE THE JOINT OF INFLAMMATORY ARTHRITIS PATIENTS: HANDLING AND PROCESSING OF SYNOVIAL TISSUE BIOPSIES FOR HIGH THROUGHPUT ANALYSIS

Background

Inflammatory arthritis (IA) is a chronic systemic autoimmune disease of unknown aetiology, which affects the joints. While studies of immune cell populations in peripheral blood have been informative regarding potential immune cell dysfunction and possible patient stratification, there are considerable limitations in identifying the early events that lead to synovial inflammation. The joint, as the site of inflammation and the local microenvironment, exhibit unique characteristics that contribute to disease pathogenesis. The limited availability of synovial tissue (ST) biopsies is a key incentive for the utilisation of high-throughput techniques in order to maximise information gain.

Objectives

This work aims to provide an overview of key methods and novel techniques that are used in the handling, processing and analysis of ST biopsies and the potential synergy between these techniques.

Methods

We describe the utilisation of high dimensionality flow cytometric analysis, single cell RNA sequencing, ex vivo functional assays, including T cell activation, endocytosis and two-photon fluorescent lifetime imaging microscopy (FLIM).

Results

When comparing different methods for ST cell suspension generation we observed that the combination of mechanical and enzymatic digestion resulted in the release of considerably higher numbers of total viable cells when compared to mechanical digestion alone, although consideration should be taken in the cleaving of extracellular markers, like CD27. We next compared two different cryopreservation methods to that of freshly digested ST and observed similar viability and frequency of immune cells. Functional characterisation of ST cells can be challenging due to the high number of cells required for analysis, herein, we utilised the above protocols to establish ST viable cell suspensions and optimised different experimental approaches for phenotypical/functional characterisation. To investigate the functional consequence of OxPhos inhibition on ST T-cell polyfunctionality, ex-vivo ST cell suspensions from IA patients were stimulated with PMA/Ionomycin in the presence/absence of FCPP followed by metabolic profile characterisation via FLIM and high dimensionality flow-cytometric analysis for T cell-derived cytokines. Treatment with FCPP resulted in a decreased in T-cell polyfunctionality specifically in co-expression of TNF-α,-IL-2,-IFN-γ,IL-17A, -GM-CSF, an effect associated with a shift in their metabolic profile. In addition, freshly digested ST cell suspensions were subjected to an optimized assay to evaluate endocytosis in multiple populations simultaneously without the need for cell sorting. Briefly, digested cells were incubated in parallel at 4°C (passive endocytosis) and 37°C (active endocytosis) with DQ OVA(Ovalbumin). ST cells were then stained for multiple populations, demonstrating differential endocytosis capacity across pathotypes and disease controls.

Finally, utilisation of novel bioinformatics analysis of RNAseq a data showed differential gene expression and pathway enrichment involved in IA pathogenesis and allowed for the comparison of cell specific enrichment scores and transcription factor usage based on pathotype and gender.

Conclusion

The introduction of new powerful techniques in the study of ST inflammation, brings new challenges and significant opportunities. These approaches will accelerate our path towards understanding of the mechanisms involved in the pathogenesis of IA and lead to the identification of new avenues of therapeutic intervention.

Acknowledgements

We would like to thank all the patients who consented to be involved in this study.

Disclosure of Interests

None declared.

OP0013 LOSS OF SYNOVIAL TISSUE MACROPHAGE HOMEOSTASIS PRECEDES RHEUMATOID ARTHRITIS CLINICAL ONSET

Background

Synovial tissue macrophages significantly contribute to Rheumatoid Arthritis, yet the precise nature/function of macrophage subsets within the inflamed joint remains unexplored.

Objectives

To fully explore the spectrum of distinct macrophage activation states residing within the synovium of RA, at risk and healthy individuals.

Methods

Single-cell synovial tissue suspensions from RA (n=44), IAR (n=5), HC (n=11), PsA (n=11) and OA (n=4) were obtained, and synovial macrophage subsets examined by advanced multiparameter flow cytometric analysis, bulk RNA-sequencing, metabolic and functional assays.

Results

Multidimensional analysis identifies enrichment of CD206+CD163+ synovial-tissue macrophages co-expressing CD40 in the RA joint compared to healthy synovial-tissue, with frequency of CD206+CD163+CD40+ macrophages associated with increased disease activity and treatment response. In contrast, CX3CR1-expressing macrophages which form a protective barrier in healthy synovium are significantly depleted in RA. Importantly this signature of enriched CD40 expression coupled with depleted CX3CR1 expression is an early phenomenon, occurring prior to clinical manifestation of disease in individuals ‘at-risk’ of RA (IAR). RNAseq and metabolic profiling of sorted RA synovial-macrophages identified that this population is transcriptionally distinct, displaying unique inflammatory, phagocytic and tissue-resident gene signatures, paralleled by a bioenergetically stable profile as indicated by NAD(P)H emission. Functionally CD206+CD163+ RA macrophages are potent producers of pro-inflammatory mediators (reversed by CD40-signalling inhibition) and induce an invasive phenotype in healthy synovial-fibroblasts. These findings identify a distinct pathogenic population of synovial-tissue macrophage involved in shaping the immune response in RA. Crucially, this signature is present pre-disease representing a unique opportunity for early diagnosis and therapeutic intervention.

Conclusion

We have identified a novel population of tissue-resident macrophages in the RA synovium which are transcriptionally/metabolically distinct and capable of contributing to disease pathology. Uncovering the molecular patterns and cues that transform this immunoregulatory macrophage population into a dysfunctional inflammatory activation state may provide opportunities to reinstate joint homeostasis in RA patients.

Disclosure of Interests

Megan Hanlon: None declared, Mary Canavan: None declared, Nuno Neto: None declared, Qingxuan Song Employee of: Employee of Janssen Pharmaceuticals, Phil Gallagher: None declared, Ronan Mullan: None declared, Conor Hurson: None declared, Barry Moran: None declared, Michael Monaghan: None declared, Sunil Nagpal Employee of: Employee of Janssen Pharmaceuticals, Douglas Veale Consultant of: Janssen, Eli Lilly, Pfizer, Ursula Fearon Consultant of: Janssen, Eli Lilly, Pfizer

Pharmacologic profiling reveals lapatinib as a novel antiviral against SARS-CoV-2 in vitro

The emergence of SARS-CoV-2 virus has resulted in a worldwide pandemic, but effective antiviral therapies are not widely available. To improve treatment options, we conducted a high-throughput screen to uncover compounds that block SARS-CoV-2 infection. A minimally pathogenic human betacoronavirus (OC43) was used to infect physiologically-relevant human pulmonary fibroblasts (MRC5) to facilitate rapid antiviral discovery in a preclinical model. Comprehensive profiling was conducted on more than 600 compounds, with each compound arrayed across 10 dose points. Our screening revealed several FDA-approved agents that can attenuate both OC43 and SARS-CoV-2 viral replication, including lapatinib, doramapimod, and 17-AAG. Importantly, lapatinib inhibited SARS-CoV-2 RNA replication by over 50,000-fold. Further, both lapatinib and doramapimod could be combined with remdesivir to improve antiviral activity in cells. These findings reveal novel therapeutic avenues that could limit SARS-CoV-2 infection.

Critical COVID-19 rarely associated with left ventricular systolic impairment

Introduction

For some individuals infection with SARS-CoV-2 leading to COVID-19 can result in a life-threatening multi-system disease. Multiple potential pathophysiological mechanisms for the development of cardiovascular complications have been postulated [1]. Early reports suggested that more than a third of hospitalised patients undergoing TTE had evidence of LV impairment [2].

Purpose

To ascertain the incidence of ventricular impairment among critically ill adults with COVID-19 admitted to the intensive care unit (ICU).

Methods

Retrospective analysis of transthoracic echocardiograms (TTE) performed on patients admitted to ICU with COVID-19 between 10th March and 10th May 2020. Archived studies were reviewed by accredited professionals. Studies were performed according to a modified British Society of Echocardiography (BSE) Level 1 protocol [3], with the addition of right ventricle (RV) focused apical 4 chamber, as well as apical 2 and 3 chamber views, and without ECG synchronisation as per infection control protocols. In the majority of patients the left ventricular ejection fraction (LVEF) was estimated from biplane Simpson's method. The RV function was assessed using the TAPSE in most patients. In the remaining patients the LV or RV function was visually assessed.

Results

Of 179 patients admitted to ICU, 85 (47.5%) had at least one TTE of diagnostic quality. Studies were performed a median of 7 days after ICU admission (IQR 3–17 days). Baseline and clinical characteristics and key echocardiographic measurements are summarised in table 1. The majority of patients were undergoing mechanical ventilation at the time of the scan (94.1%). One hundred and fifty-nine patients (89%) had elevated Troponin T (≥14ng/L) on the day of the study. LV systolic impairment (LVSD) was present in 5 patients (6.0%). This was known to be chronic in 3 patients (1 with coronary artery disease, 1 with chemotherapy induced cardiomyopathy and 1 with dilated cardiomyopathy of unknown aetiology), whilst pre-morbid cardiac function was unknown in the other 2 patients. No patient had severe LVSD (LVEF ≤35%). RV systolic dysfunction (RVSD) was found in 25 patients (31.3%). Amongst patients receiving mechanical ventilation there was no significant difference in Positive End Expiratory Pressure (PEEP) between patients with and without RVSD (9.4cmH2O vs. 9.8cmH2O, p=0.64), however there was a non-significant trend towards lower PaO2/FiO2 (P/F ratio) amongst patients with RVSD (18.9kPa vs 25.7kPa, p=0.07).

Conclusions

In contrast to other studies which have reported high frequency of LV impairment amongst hospitalised patients with COVID-19 [3], de novo LVSD was rarely found in this study, occurring in just 2 patients (2.4%), and being severe in neither. RV dilatation and systolic impairment were commonly found. A trend towards lower P/F ratios in patients with RVSD suggests severity of lung injury may be a factor in developing RV impairment.

Funding Acknowledgement

Type of funding sources: None.

OP0028 CD206+CD163+ PATHOGENIC MACROPHAGES ENRICHED IN RHEUMATOID ARTHRITIS SYNOVIAL TISSUE WITH DISTINCT TRANSCRIPTIONAL SIGNATURES

Background:

Synovial tissue macrophages are an exquisitely plastic pool of innate cells that play a key role in RA disease progression. However, the precise nature, diversity, and function of macrophage subsets within the inflamed joint remains unexplored.

Objectives:

Therefore, the aims of this study are to phenotypically, transcriptionally and functionally characterise synovial tissue macrophages residing within the inflamed joint.

Methods:

Rheumatoid Arthritis, Psoriatic Arthritis, Osteoarthritis and healthy control synovial-tissue biopsies and synovial-fluid mononuclear cells were analysed using the following panel (CD40,-CD45,-CD64,-CD68,-CD163,-CD206,-CD253,-CCR4,-CCR7,-CXCR1,-CXCR3). CD206+CD163+ and CD206-CD163- macrophages were sorted from RA synovial-tissue by FACSAria sorter; RNAseq and FLIM analysis, autologous T-cell co-culture and heathy fibroblast experiments performed. Cytokine expression was measured by MSD immunoassay.

Results:

RA synovial tissue and fluid macrophages display markers typical of both M1 (CD40+CD253+) and M2 (CD206+CD163+) macrophages with a spectrum of macrophage activation states identified. Within this spectrum, significant enrichment of dominant CD206+CD163+ macrophage-subtype is present in synovial tissue versus fluid (p<0.05). CD206+CD163+ synovial tissue macrophages express significantly more CD40 than synovial fluid (p<0.0003), positively correlate with disease activity (r=0.6, p<0.01), with baseline levels predicting response to therapy (p<0.05). Moreover, CD206+CD163+CD40+ macrophages are enriched in RA synovial tissue compared to PsA and OA pathotypes (p<0.05). While the CD206+CD163+ subset is present in healthy synovial tissue, expression of CD40 is completely absent in healthy synovium (p<0.05) with dramatically decreased expression of CX3CR1 on RA macrophages. RNA-seq analysis indicates that CD206+CD163+ population is transcriptionally distinct from synovial tissue CD206-CD163-, synovial fluid CD206+CD163+, and RA monocyte-derived M1/M2 macrophages, with unique tissue-resident gene signatures. Moreover, differing metabolic demands between CD206+CD163+ and CD206-CD163- subsets was demonstrated by RNAseq and FLIM analysis. CD206+CD163+ macrophages enhance autologous T-cell responses, spontaneously secrete high levels of pro-inflammatory cytokines and activate healthy fibroblasts towards pro-inflammatory mechanisms thus further contributing to the local inflammatory response. Finally, inhibition of CD40 activity abrogates the expression of pro-inflammatory mediators (TNFa, IL-1B, IL-6, IFNy) and induces IL-10 expression in sorted CD206+CD163+ synovial tissue-macrophages suggesting a key role for CD40 in driving this pathogenic phenotype.

Conclusion:

This data identifies for the first-time enrichment of a previously undescribed dysfunctional dominant and transcriptionally distinct macrophage subtype in RA synovial tissue. Taken together, this data provides a greater understanding of the critical role tissue-resident macrophages play in perpetuating inflammation in RA. Further investigation of the molecular patterns and cues that shape specific synovial macrophage subsets may provide opportunities to reinstate RA joint homeostasis.

Disclosure of Interests:

Megan Hanlon: None declared, Mary Canavan: None declared, Qingxuan Song Employee of: Janssen Research & Development, Nuno Neto: None declared, Phil Gallagher: None declared, Ronan Mullan: None declared, Conor Hurson: None declared, Michael Monaghan: None declared, Sunil Nagpal Employee of: Janssen Research & Development, Douglas Veale Speakers bureau: Abbvie, Janssen, Novartis, MSD, Pfizer, UCB, Consultant of: Abbvie, Janssen, Novartis, MSD, Pfizer, UCB, Grant/research support from: Janssen, Abbvie, Pfizer, UCB, Ursula Fearon Speakers bureau: Abbvie, Grant/research support from: Janssen, Abbvie, Pfizer, UCB

POS0007 LOSS OF BALANCE BETWEEN PROTECTIVE AND PRO-INFLAMMATORY SYNOVIAL TISSUE T CELL POLYFUNCTIONALITY PREDATES CLINICAL ONSET OF RHEUMATOID ARTHRITIS

Background:

Effective treatment of Rheumatoid arthritis (RA) patients is achievable within a short window of opportunity following diagnosis. T-cells are early drivers of synovial inflammation of RA, therefore, identification of pathogenic T-cell subsets at the synovial tissue of pre-RA, arthralgia subjects, would greatly improve our understanding of disease pathogenesis. Comparative analysis of healthy control, arthralgia subject and RA-patient derived synovial tissue T-cell responses will lead to the identification of pathogenic as well as protective cytokine milieu, thus enabling the identification of early therapeutic targets to help steer the immune response towards resolution.

Objectives:

Characterization of T-cell polyfunctionality in the periphery and synovial tissue of ’at-risk; subjects (Arthralgia) RA-patients and healthy controls (HC).

Identification of specific, pathogenic, synovial tissue T-cell subsets.

Methods:

Synovial biopsies from RA, AR and HC were obtained by arthroscopic surgery followed by RNAseq analysis (Guo et al., PLoS One, 2018). Single cell synovial tissue cell suspensions from RA, AR and HC and paired PBMC were stimulated in vitro and polyfunctional synovial T-cell subsets examined by flow cytometric analysis, SPICE visualization and FlowSom clustering. Flow-Imaging, was utilised to confirm specific T-cell cluster identification. Fluorescent Lifetime Imaging Microscopy (FLIM) was used to visualise metabolic status of specific T-cell populations.

Results:

T-cell associated pro-inflammatory gene pathways were increased in RNAseq analysis of RA-patient and arthralgia subject compared to HC synovial tissue biopsies. Flow cytometric analysis of pro-inflammatory cytokine (TNF-α, IFN-γ, IL-2, GM-CSF, IL-17A, IL-22) production and SPICE analysis of ex vivo stimulated T-cells revealed marked polyfunctionality of arthralgia subject synovial T-cells, thus providing evidence for a dysregulated synovial T-cell response that pre-dates clinical onset of disease. Importantly, HC synovial tissue harbours a small, albeit surprisingly polyfunctional, CD4 T-cell population characterised by significantly increased IL-4 and GM-CSF cytokine production compared to arthralgia subject (P<0.001 and P=0.01) and RA-patient (P<0.001 and P=0.004) synovial tissue. However, not all polyfunctional T-cells are equal in their pathogenic potential. Therefore, in order to identify highly pathogenic synovial T-cells, cluster analysis of flow cytometric data using the unsupervised algorithm FlowSom was performed and led to the identification of specific T-cell clusters with unique polyfunctionality characteristics. Specifically a cluster of CD4+CD8+ double positive (DP) T-cells with high polyfunctionality scores was identified. Hybrid flow cytometry and imaging technique confirmed the co-expression of CD4 and CD8 by a synovial T-cell population. DP T-cells are enriched in RA-patient synovial fluid and synovial tissue and arthralgia subject synovial tissue, but are absent from HC synovial tissue. Importantly, DP T-cell synovial accumulation strongly (P=0.002) correlates with DAS28(CRP) of RA-patients. Initial studies utilising the novel, non-invasive FLIM technique for visualisation of cellular NAD, revealed that DP T-cells have a metabolic profile indicative of activated memory T-cells.

Conclusion:

These data highlight a key early loss of balance between protective and pathogenic synovial T-cell polyfunctionality and the emergence of specific, highly polyfunctional and pathogenic T-cell clusters in RA.

Figure 1.

Identification of highly polyfunctional and pro-inflammatory synovial DP T-cells. A. Cluster analysis of RA-patient synovial tissue T-cells (asterisks indicate DP T-cell clusters). B. Flow imaging of CD4+, CD8+ and DP synovial T-cells. C. SPICE flow cytometric data visualization of DP arthralgia subject and RA-patient synovial T-cells. D. Correlation between the frequency of RA-patient synovial DP T-cells and disease severity.

Disclosure of Interests:

Achilleas Floudas: None declared, Nuno Neto: None declared, Mary Canavan: None declared, Trudy McGarry Employee of: Novartis, Vinod Krishna Employee of: Janssen, Sunil Nagpal Employee of: Janssen, GSK, Michael Monaghan: None declared, Douglas Veale Speakers bureau: Abbvie, Janssen, Novartis, MSD, Pfizer, UCB, Consultant of: Abbvie, Janssen, Novartis, MSD, Pfizer, UCB, Grant/research support from: Janssen, Abbvie, Pfizer, UCB, Ursula Fearon Speakers bureau: Abbvie, Grant/research support from: Janssen, Abbvie, Pfizer, UCB.

Mitral regurgitation in acute heart failure: prevalence and response to treatment

 

Heart failure (HF) affects an estimated 90 000 people within the UK. As a consequence of ventricular remodelling, mitral regurgitation (MR) is common in patients with HF, further contributing to poor prognosis, frequent hospitalisation, and higher rates of mortality. Conventional treatment options include medical therapy, cardiac resynchronisation and conventional mitral valve surgery, with transcatheter mitral valve repair (TMVR) reserved for symptomatic patients with left ventricular dysfunction and multiple comorbidities, considered high surgical risk.

Aim

Our objectives were to determine: (1) the proportion of patients with an acute HF admission, ejection fraction (EF) of &lt;50% and moderate or more MR; (2) the effectiveness of optimal medical therapy (OMT) in reducing the severity of MR and symptoms; (3) the number of patients with moderate or more MR, EF &lt;50% and symptoms despite OMT.

Method

We performed a retrospective analysis of patients who presented with acute HF to two large tertiary centres over a five-year period. Based on a combination of electronic care records, and national registry and mortality data, we determined baseline symptoms, symptom progression, and co-morbidities. Echocardiography data was used to assess the degree of MR and EF. Where patients underwent a subsequent echocardiogram on OMT, the change in the degree of MR, EF and symptoms (NYHA class) was examined.

Results

Over a five-year period (Jan 2012–Dec 2017), 1884 patients presented with acute HF. Of this cohort, 302 (16%) had moderate or more MR and EF of &lt;50%. Mortality amongst patients with moderate or more MR was 29.9% at one year (compared to 26.9% for those with less than moderate MR, p=0.058). Of this cohort, 45% had sufficient clinical and echocardiographic paired follow up data to enable assessment of the effects of OMT (Age 78±20.78; Male n=76 (56.3%). This analysis showed, despite OMT, all 135 patients still had moderate or more MR. When compared with previous echocardiography data, 11 (8%) patients showed a reduction in the severity of MR which meant 92% (124) of patient with MR either saw no improvement or worsening of their MR severity. Of those with severe MR, 23% (7) demonstrated an improvement in the degree of MR following OMT. Clinically 70 (51.4%) patients had an improvement in symptoms. There was significant improvement in the NYHA class pre and post optimisation of medical therapy (p&lt;0.001) across all grades of MR. Despite OMT, 124 (92%) patients with moderate or more MR and EF &lt;50% remained symptomatic.

Conclusions

A large portion of patients who present with acute HF have moderate or more MR. Although medical therapy is effective in providing some relief from symptoms, the large majority of patients continue to have moderate or more MR. We propose a portion of these patients are potential candidates for TMVR, and should be considered for further intervention.

Funding Acknowledgement

Type of funding source: None

P606High intermodality variability in ejection fraction measured by echocardiography, cardiac magnetic resonance and single photon emission computed tomography in chronic coronary artery disease patients

Background

Clinical treatment strategies are often based on measurement of left ventricular ejection fraction (LVEF). There is limited evidence about variations in LVEF when measured by different imaging modalities.

Purpose

To investigate the intermodality variability of LVEF measured by two-dimensional echocardiography (2DE), three-dimensional echocardiography (3DE), cardiac magnetic resonance (CMR), and single photon emission computed tomography (SPECT) in patients with chronic coronary artery disease (CAD).

Methods

Patients from a multicenter study (DOPPLER-CIP – Determining optimal noninvasive parameters for the prediction of left ventricular remodeling in chronic ischemic patients) with chronic CAD were included. LVEF was measured by CMR and at least one additional modality. In each modality, LVEF was measured by a core laboratory independently of the other modalities. Measurements of LVEF by CMR were compared to 2DE, 3DE and SPECT using correlation and Bland-Altman plots.

Results

A total of 343 patients were included. Mean age was 63.9±8.3 years and 253 (74%) were males. Mean LVEF by CMR was 61.8±11.6%. Correlations between CMR LVEF and other modalities were moderate for 2DE and 3DE, and good for SPECT (Figure A-C). CMR had significantly greater correlation to SPECT, compared to 2DE and 3DE. Bland-Altman plots indicated relatively wide limits of agreement between all modalities, ranging from 31% to 42% (Figure, D-F). Mean absolute difference of LVEF between CMR and other modalities were 8.5% for 2DE, 9.0% for 3DE, and 8.3% for SPECT. The percentage of measurements that fell within a range of 5% difference compared to CMR LVEF was 41% for 2DE, 34% for 3DE and 37% for SPECT (all p>0.05).

Conclusions

In a multicenter study with chronic CAD patients, LVEF assessed by CMR had better correlation to SPECT, compared to 2DE and 3DE. However, there was considerable variability among all three modalities that were compared to CMR. Awareness of these variations are important in clinical management.

An actuatable soft reservoir modulates host foreign body response

The performance of indwelling medical devices that depend on an interface with soft tissue is plagued by complex, unpredictable foreign body responses. Such devices-including breast implants, biosensors, and drug delivery devices-are often subject to a collection of biological host responses, including fibrosis, which can impair device functionality. This work describes a milliscale dynamic soft reservoir (DSR) that actively modulates the biomechanics of the biotic-abiotic interface by altering strain, fluid flow, and cellular activity in the peri-implant tissue. We performed cyclical actuation of the DSR in a preclinical rodent model. Evaluation of the resulting host response showed a significant reduction in fibrous capsule thickness (P = 0.0005) in the actuated DSR compared with non-actuated controls, whereas the collagen density and orientation were not changed. We also show a significant reduction in myofibroblasts (P = 0.0036) in the actuated group and propose that actuation-mediated strain reduces differentiation and proliferation of myofibroblasts and therefore extracellular matrix production. Computational models quantified the effect of actuation on the reservoir and surrounding fluid. By adding a porous membrane and a therapy reservoir to the DSR, we demonstrate that, with actuation, we could (i) increase transport of a therapy analog and (ii) enhance pharmacokinetics and time to functional effect of an inotropic agent. The dynamic reservoirs presented here may act as a versatile tool to further understand, and ultimately to ameliorate, the host response to implantable biomaterials.

Prominent inter-scallop separations of the posterior leaflet of the mitral valve: an important cause of 'pathological' mitral regurgitation

The 2012 World Heart Federation (WHF) criteria for echocardiographic diagnosis of rheumatic heart disease (RHD) identify that the finding of 'pathological' mitral regurgitation (MR) in a screened individual increases the likelihood of detecting underlying RHD. Cases of isolated "pathological MR are thus identified as 'borderline RHD'. A large-scale echocardiographic screening program (Echo in Africa) in South Africa has identified that inter-scallop separations of the posterior mitral valve leaflet (PMVL) can give rise to 'pathological' MR. The authors propose that this finding when associated with isolated 'pathological' MR is unrelated to the rheumatic disease process. In this case report, we present two examples of 'pathological' MR related to inter-scallop separation from the Echo in Africa image database. We provide additional screening tips to accurately identify this entity.

Contrast echocardiography in daily clinical practice

Ultrasound contrast agents have unique acoustic properties that enable them to enhance the cardiac blood flow and thus are used broadly in modern echocardiography laboratories for salvage of nondiagnostic studies, improving accuracy and reducing variability even in the presence of adequate image quality. Contrast echocardiography is also used as an adjunctive technique when unenhanced echocardiography falls short in the differentiation of cardiac structural abnormalities such as cardiac masses. Ultrasound contrast agents are pure intravascular tracers. Development of innovative ultrasound imaging techniques has led to myocardial perfusion imaging with contrast echocardiography. Although currently an off-label indication, it has been shown that perfusion imaging with contrast echocardiography adds incremental value to stress echocardiography in the detection of coronary artery disease. Moreover, it can be used for assessment of myocardial viability. In this paper we briefly discuss the basics of contrast echocardiography and its use in daily clinical practice.

Network geometry of evidence from randomised controlled trials addressing donor selection and source of haematopoietic progenitor cells used in allogeneic transplantation: a systematic scoping review

BACKGROUND AND METHODS

A scoping review of randomised controlled trials (RCTs) addressing source of cells and choice of donor for allogeneic haematopoietic cell transplantation (HCT) was performed to create a network of best evidence that allows us to identify new potential indirect comparisons for the strategic development of future studies that connect to the existing evidence network.

RESULTS

A total of 19 eligible RCTs (2589 total patients) were identified. Nine studies (1566 patients) compared clinical outcomes following the use of peripheral blood progenitor cells (PBPCs) with bone marrow (BM) from matched related donors (eight studies) or matched unrelated donors (one study). The remaining studies compared BM or PBPCs with various methods of BM stimulation or manipulation (six studies), compared different methods of surface molecule-based selection and/or depletion of grafts (two studies) or compared the optimal number of units for paediatric cord blood transplantation (two studies). No published RCTs compared different types of donors. The geometry of the evidence network was analysed to identify opportunities for potential novel indirect comparisons and to identify opportunities to expand the network. Few indirect comparisons are currently feasible due to small sample size and heterogeneity in patient diagnoses and demographics between treatment nodes in the network.

CONCLUSION

More RCTs that enrol greater numbers of similar patients are needed to leverage the current evidence network concerning donor choice and source of cells used in allogeneic HCT.

Screening for rheumatic heart disease: is a paradigm shift required?

This focused review presents a critical appraisal of the World Heart Federation criteria for the echocardiographic diagnosis of rheumatic heart disease (RHD) and its performance in African RHD screening programmes. It identifies various logistical and methodological problems that negatively influence the current guideline’s performance. The authors explore novel RHD screening methodology that could address some of these shortcomings and if proven to be of merit, would require a paradigm shift in the approach to the echocardiographic diagnosis of subclinical RHD.

Stabilizing interactions between D666-S1787 and T657-Y1792 at the A2-A3 interface support factor VIIIa stability in the blood clotting pathway

Essentials Factor VIIIa (FVIIIa) is unstable due to loss of A2; D666 and Y1792 contribute to its stability. We conducted a study to identify the interactions made at these residues at the A2-A3 interface. We present evidence for stabilizing interactions between D666-S1787 and T657-Y1792 in FVIIIa. A D666C/S1788C variant with a disulfide A2-A3 linkage has a FVIIIa decay rate that is 1% of wild-type.

SUMMARY

Background Factor (F)VIIIa activity and stability depends on the non-covalent association of the A2 subunit with the A1/A3C1C2 dimer, but the interactions that contribute to A2 association are not well defined. Previous work had shown that D666A and Y1792F mutations at the A2-A3 interface resulted in increased FVIIIa decay, suggesting that the residues were involved in bonding interactions important for FVIIIa stability. Objectives Several potential hydrogen bonding partners of D666 and Y1792 across the A2-A3 interface were selected from the low-resolution FVIII crystal structure, and we used mutagenesis and biochemical analysis to examine the bonding interactions occurring at D666 and Y1792. Methods Using a series of stability and functional analyses, we analyzed FVIII variants in which D666 and Y1792 were each swapped with the residues of potential bonding partners. Results and conclusions We present evidence for hydrogen bonds between D666 and S1787 and between Y1792 and T657 that are important for FVIIIa stability. D666S/S1787D and T657Y/Y1792T variants each displayed wild-type (WT)-like FVIIIa stability and performed like WT FVIII in a series of functional analyses, whereas D666S, S1787D, and Y1792T single variants showed increased FVIIIa decay and a T657Y variant had little FVIIIa activity. These results suggest that WT hydrogen bonds are disrupted with the single mutations but maintained in the swap variants. Furthermore, mutation of D666 and S1788 to cysteine resulted in disulfide bond formation across the A2-A3 interface, confirming the close proximity of D666 and S1787, and this covalent attachment of the A2 subunit significantly increased FVIIIa stability.

An antibody fragment functionalized dendritic PEGylated poly(2-(dimethylamino)ethyl diacrylate) as a vehicle of exogenous microRNA

The translation of interfering RNA to the clinic requires more effective delivery agents to enable safe and efficient delivery. The aim of this work was to create a multi-functional delivery agent using deactivation enhanced ATRP synthesis of poly(dimethylamino)ethyl methacrylate (pDMAEMA)-co-PEGMEA/PEGDA (pD-b-P/DA) with linear pDMAEMA as a macro-initiator. The pD-b-P/DA was characterized for its potential to bind synthetic microRNA mimics to form structures and reacted with antibody-derived fragments (Fabs) using Michael-type addition. Conjugation of antibody fragments was verified using SDS-PAGE. Functional delivery of these interfering RNA complexes was proven using a dual luciferase reporter assay. Functional silencing of a reporter gene was improved by complexation of microRNA mimics with pD-b-P/DA alone and with Fab-decorated pD-b-P/DA. The improved silencing with Fab-decorated pD-b-P/DA was evident at 48 h but disappeared at 96 h. The resultant agent enables complexation of nucleic acid (microRNA mimic) and facile conjugation of antibody fragments via a Michael-type addition. In conclusion, this platform is effective at silencing in this reporter system and has potential as an effective delivery system of interfering RNA.

Impedance spectroscopy for the non-destructive evaluation of in vitro epidermal models

Purpose

Reconstructed human epidermis (RHE) is standardly used for the risk assessment of chemical compounds. However, analysis is dependent on invasive methods such as histological processing or 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) staining.

Methods

As an alternative, we have developed a non-destructive technology to analyze the integrity of epidermal equivalents based on impedance spectroscopy. RHEs were generated and impedance spectra were recorded. from these spectra, we extrapolated electrical characteristics such as the capacitance and the ohmic resistance. Furthermore, the measurable electrical parameters were used to quantify the effects of mechanical and chemical disruption of the epidermal integrity.

Results

A fully matured RHE exhibits typical impedance spectra in a frequency ranging between 1 Hz and 100 kHz, which is comparable to the spectra of freshly isolated human epidermal biopsies. We could show that, during RHE maturation, these characteristics change significantly. Thus, capacitance and ohmic resistance can be employed as a criterion for the quality control of skin equivalents. Additionally, our application of impedance spectroscopy reveals sufficient sensitivity to detect a transient decreased ohmic resistance caused by 2-propanol, which is classified as a non-irritant by MTT assays.

Conclusion

These results indicate that impedance spectroscopy can be employed as a non-destructive complementary method to assess mild irritative effects, which is currently not possible.

Enhanced factor VIIIa stability of A2 domain interface variants results from an increased apparent affinity for the A2 subunit. Results from an increased apparent affinity for the A2 subunit

Factor (F)VIIIa, a heterotrimer comprised of A1, A2, and A3C1C2 subunits, is labile due to the tendency of the A2 subunit to dissociate from the A1/A3C1C2 dimer. As dissociation of the A2 subunit inactivates FVIIIa activity, retention of A2 defines FVIIIa stability and thus, FXase activity. Earlier results showed that replacing residues D519, E665, and E1984 at the A2 domain interface with Ala or Val reduced rates of FVIIIa decay, increasing FXa and thrombin generation. We now show the enhanced FVIIIa stability of these variants results from increases in inter-A2 subunit affinity. Using a FVIIIa reconstitution assay to monitor inter-subunit affinity by activity regeneration, the apparent Kd value for the interaction of wild-type (WT) A2 subunit with WT A1/A3C1C2 dimer (43 ± 2 nM) was significantly higher than values observed for the A2 point mutants D519A/V, E665A/V, and E1984A/V which ranged from ~5 to ~19 nM. Val was determined to be the optimal hydrophobic residue at position 665 (apparent Kd = 5.1 ± 0.7 nM) as substitutions with Ile or Leu at this position increased the apparent Kd value by ~3- and ~7-fold, respectively. Furthermore, the double mutant (D519V/E665V) showed an ~47-fold lower apparent Kd value (0.9 ± 0.6 nM) than WT. Thus these hydrophobic mutations at the A2 subunit interfaces result in high binding affinities for the A2 subunit and correlate well with previously observed reductions in rates in FVIIIa decay.

The combined treatment of aortic stenosis and abdominal aortic aneurysm using transcatheter techniques: a case report

We describe the case of an 85 year old lady with symptomatic aortic stenosis (AS) with a history of previous coronary artery bypass grafting (CABG), who was referred for consideration of aortic valve replacement (AVR). Echocardiography revealed severe AS with peak gradient of 92 mmHg, orifice area of 0.6 cm2 and preserved left ventricular function. Computed tomography (CT) aortogram revealed a diffusely calcified aorta and an infrarenal abdominal aortic aneurysm (AAA) measuring 6.5 cm. For symptomatic and prognostic reasons she needed treatment of both the AAA and AS. Her calculated logistic EuroSCORE for AVR was 39%. Following discussion at a multidisciplinary forum, it was agreed that the best way to offer her treatment with the lowest risk was by using transcatheter techniques for both pathologies. She subsequently underwent transcatheter aortic valve implantation (TAVI) via the transapical approach to treat her AS, and 3 months later, endovascular stenting of her infrarenal AAA. She recovered well from both procedures. At 6 week follow up, her cardiac symptoms had improved considerably, and echocardiography revealed a mean AV gradient of 7 mmHg with good left ventricular function. Ultrasound of her abdomen revealed exclusion of the aneurysm sac with no endoleak. This is the first described case of TAVI and endovascular treatment of an AAA as a staged procedure.

Cytological recognition of herpes simplex virus infection in bronchoscopic samples from the respiratory tract

Cytological features suggesting herpes simplex virus (HSV) infection in samples obtained at bronchoscopy have been described only very rarely in routinely processed samples. We report four cases where evidence of HSV infection was identified morphologically in samples processed using thin-layer techniques, with polymerase chain reaction confirmation of the presence of virus in three cases. We suggest that the increased morphological clarity provided by this technique for processing these cytology samples may result in the morphological features of viral infection being seen more frequently. Pathologists reporting such samples need to be aware of this possibility in order to avoid potential misinterpretations. In addition, however, respiratory and intensive care physicians unused to receiving cytology reports indicating 'HSV infection' need to be aware that the significance is uncertain and in most cases it is likely to indicate the reactivation of a latent infection.

Comparative study of bipolar eletrocoagulation versus argon plasma coagulation for rectal bleeding due to chronic radiation coloproctopathy

BACKGROUND AND STUDY AIM

Chronic radiation coloproctopathy (CRCP) is a well-recognized complication of radiotherapy, with rectal bleeding the most common presentation. It is frequently refractory to conservative management, but the optimal endoscopic treatment of bleeding secondary to CRCP is still controversial. The efficacy and safety of bipolar eletrocoagulation (BEC) and argon plasma coagulation (APC) in the management of bleeding from CRCP were evaluated and compared.

PATIENTS AND METHODS

30 patients (mean age 67.4 years) with active and chronic bleeding from telangiectasias, were randomly allocated to BEC or APC and stratified by severity of CRCP according to clinical severity and endoscopic findings (Saunders score). Success was defined as eradication of all telangiectasias, and therapeutic failure as need for more than seven sessions or for other treatment. Complications were categorized as minor (e.g. fever, anal or abdominal pain) or major (hemorrhagic).

RESULTS

Both treatments were equally effective for the treatment of CRCP rectal bleeding. Only one failure was observed in each group (P = 1.000). There was no significant difference between the two groups regarding number of sessions, minor or major complications, or relapse. However, overall complication rate was significantly higher in the BEC group (P = 0.003).

CONCLUSIONS

BEC and APC are both effective for the therapy of bleeding telangiectasias from CRCP. There are probably no major differences between them. Although APC seemed safer than BEC in this investigation, further studies, involving a much larger population, are needed to assess the complication rates and determine the best management option.

The incidence of bacteraemia after argon plasma coagulation in patients with chronic radiation proctocolitis

AIM

Argon plasma coagulation (APC) is considered a safe treatment for haemorrhagic chronic radiation proctocolitis (CRPC), but bacteraemia is a rare complication. The study aimed to evaluate the frequency of bacteraemia after APC.

METHOD

A prospective study of 21 patients who underwent APC (30 procedures) for CRPC was carried out. Blood cultures (Bactec(®) ) were obtained before and 30 min after the procedure (60 samples total). Patients were monitored for 48 h after the procedure to detect signs of infection.

RESULTS

None of the 21 patients had fever or any sign suggestive of infection after any of the 30 sessions. All baseline blood cultures were negative and two (7%) of the 30-min blood cultures were positive (Staphylococcus hominis n = 1; Streptococcus bovis and Rhodotorula sp n = 1). The first was likely to be a contaminant and the second patient had no evidence of any other colonic disease (neoplasia or polyps) beside CRPC.

CONCLUSION

APC is a low-risk procedure regarding bacteraemia and does not warrant prophylactic antibiotic administration.

Parent stress and child behaviour among young children with type 1 diabetes

BACKGROUND

Parents of young children with type 1 diabetes (T1D) are responsible for executing a complex daily management regimen and are at risk for elevated levels of stress. Normative misbehaviour during the preschool years can complicate T1D management, and interpretation of behavioural concerns may vary because of child health status and parent stress. Within a paediatric transactional model framework, child characteristics (e.g. behaviour problems, metabolic control) and parent functioning (e.g. parenting stress, anxiety) likely impact one another.

METHODS

Parents of 2- to 6-year-old children with T1D completed self-report measures, including the Pediatric Inventory for Parents (PIP), State-Trait Anxiety Inventory (STAI), Eyberg Child Behavior Inventory (ECBI), and 24-h Recall Interviews. Medical data were obtained by parent report and medical record review. It was hypothesized that greater parent stress and child blood glucose variability would be significantly associated with greater parent-reported child behaviour concerns.

RESULTS

Moderate levels of parent stress and child behaviour problems were endorsed; however, parents perceived children's misbehaviour as problematic, particularly with relation to tasks relevant to diabetes management (e.g. bedtimes and mealtimes). Structural equation modelling indicated that greater general anxiety and paediatric parenting stress was associated with parent report of more problematic child behaviour. Blood glucose variability did not significantly contribute to this relationship.

CONCLUSIONS

The stress experienced by parents of young children with chronic illness appears to relate to their perception of their children's behaviour problems. Parents' experiences with developmentally normative misbehaviour may interfere with disease management and exacerbate parents' stress and the subsequent impact on well-being. Implications for supporting parents and children with T1D are discussed.