Automated antibody dispensing to improve high-parameter flow cytometry throughput and analysis

Over the past decade, the flow cytometry field has witnessed significant advancements in the number of fluorochromes that can be detected. This enables researchers to analyze more than 40 markers simultaneously on thousands of cells per second. However, with this increased complexity and multiplicity of markers, the manual dispensing of antibodies for flow cytometry experiments has become laborious, time-consuming, and prone to errors. An automated antibody dispensing system could provide a potential solution by enhancing the efficiency, and by improving data quality by faithfully dispensing the fluorochrome-conjugated antibodies and by enabling the easy addition of extra controls. In this study, a comprehensive comparison of different liquid handlers for dispensing fluorochrome-labeled antibodies was conducted for the preparation of flow cytometry stainings. The evaluation focused on key criteria including dispensing time, dead volume, and reliability of dispensing. After benchmarking, the I.DOT, a non-contact liquid handler, was selected and optimized in more detail. In the end, the I.DOT was able to prepare a 25-marker panel in 20 min, including the full stain, all FMOs and all single stain controls for cells and beads. Having all these controls improved the validation of the panel, visualization, and analysis of the data. Thus, automated antibody dispensing by dispensers such as the I.DOT reduces time and errors, enhances data quality, and can be easily integrated in an automated workflow to prepare samples for flow cytometry.

Effect of sire type and a by-product based diet on performance and meat quality in growing-finishing pigs

For many years, pig production has focused on maximizing performance by selecting for maximal muscle growth and feeding diets that allow the animals to express their genetic potential. However, it is unclear whether this selection for muscle deposition has affected the capacity of pigs to cope with by-product-based diets, which rely on fat as the primary energy source instead of starches and sugars. Therefore, an experiment was set up to investigate if different types of boars affect how their progeny cope with alternative ingredients in the diet, with a possible need for adapted breeding schemes. Two types of boars within the Piétrain sire line were used based on either a high or low estimated breeding value for daily feed intake (HFI: high feed intake, low feed intake). When their progeny reached 14 weeks of age, two dietary strategies were compared: a control (CON) vs a by-product-based diet high in fat and fiber (HFF). The CON diet was mainly based on cereals (corn, wheat, barley) and soybean meal. The HFF diet was formulated to contain the same net energy, CP and digestible amino acid levels without any cereals or soybean meal. In total 192 animals were included in the experiment (48 animals/type of boar/diet) and performance, digestibility, carcass and meat quality were compared. None of the parameters showed a significant interaction (P < 0.05) between the type of boar and diet, suggesting that shifting to diets that are less prone to feed-food competition is equally feasible in different types of pigs. Type of boar did affect performance, carcass quality and intramuscular fat content. HFI pigs showed higher daily feed intake (DFI) and daily gain (P < 0.001), with no significant difference in feed conversion ratio (P = 0.205), lower carcass quality (P < 0.001) and higher intramuscular fat content (P = 0.030). For both boar types, pigs fed the CON diet performed better, with a higher daily gain (P = 0.028), DFI (P = 0.011) and dressing yield (P = 0.009) and better digestibility (P < 0.001), but without differences in feed conversion ratio or meat quality. In conclusion, there was no indication that pigs differing in feed intake capacity cope differently with a high-fat, high-fiber diet based on by-products. Different types of pigs may cope well with diets that are less prone to feed-food competition.

Activation of goblet-cell stress sensor IRE1β is controlled by the mucin chaperone AGR2

Intestinal goblet cells are secretory cells specialized in the production of mucins, and as such are challenged by the need for efficient protein folding. Goblet cells express Inositol-Requiring Enzyme-1β (IRE1β), a unique sensor in the unfolded protein response (UPR), which is part of an adaptive mechanism that regulates the demands of mucin production and secretion. However, how IRE1β activity is tuned to mucus folding load remains unknown. We identified the disulfide isomerase and mucin chaperone AGR2 as a goblet cell-specific protein that crucially regulates IRE1β-, but not IRE1α-mediated signaling. AGR2 binding to IRE1β disrupts IRE1β oligomerization, thereby blocking its downstream endonuclease activity. Depletion of endogenous AGR2 from goblet cells induces spontaneous IRE1β activation, suggesting that alterations in AGR2 availability in the endoplasmic reticulum set the threshold for IRE1β activation. We found that AGR2 mutants lacking their catalytic cysteine, or displaying the disease-associated mutation H117Y, were no longer able to dampen IRE1β activity. Collectively, these results demonstrate that AGR2 is a central chaperone regulating the goblet cell UPR by acting as a rheostat of IRE1β endonuclease activity.

The IRE1β-mediated unfolded protein response is repressed by the chaperone AGR2 in mucin producing cells

Effector mechanisms of the unfolded protein response (UPR) in the endoplasmic reticulum (ER) are well-characterised, but how ER proteostasis is sensed is less well understood. Here, we exploited the beta isoform of the UPR transducer IRE1, that is specific to mucin-producing cells in order to gauge the relative regulatory roles of activating ligands and repressing chaperones of the specialised ER of goblet cells. Replacement of the stress-sensing luminal domain of endogenous IRE1α in CHO cells (normally expressing neither mucin nor IRE1β) with the luminal domain of IRE1β deregulated basal IRE1 activity. The mucin-specific chaperone AGR2 repressed IRE1 activity in cells expressing the domain-swapped IRE1β/α chimera, but had no effect on IRE1α. Introduction of the goblet cell-specific client MUC2 reversed AGR2-mediated repression of the IRE1β/α chimera. In vitro, AGR2 actively de-stabilised the IRE1β luminal domain dimer and formed a reversible complex with the inactive monomer. These features of the IRE1β-AGR2 couple suggest that active repression of IRE1β by a specialised mucin chaperone subordinates IRE1 activity to a proteostatic challenge unique to goblet cells, a challenge that is otherwise poorly recognised by the pervasive UPR transducers.

Type 1 immunity enables neonatal thymic ILC1 production

Acute thymic atrophy occurs following type 1 inflammatory conditions such as viral infection and sepsis, resulting in cell death and disruption of T cell development. However, the impact type 1 immunity has on thymic-resident innate lymphoid cells (ILCs) remains unclear. Single-cell RNA sequencing revealed neonatal thymic-resident type 1 ILCs (ILC1s) as a unique and immature subset compared to ILC1s in other primary lymphoid organs. Culturing murine neonatal thymic lobes with the type 1 cytokines interleukin-12 (IL-12) and IL-18 resulted in a rapid expansion and thymic egress of KLRG1+CXCR6+ cytotoxic ILC1s. Live imaging showed the subcapsular thymic localization and exit of ILC1s following IL-12 + IL-18 stimulation. Similarly, murine cytomegalovirus infection in neonates resulted in thymic atrophy and subcapsular localization of thymic-resident ILC1s. Neonatal thymic grafting revealed that type 1 inflammation enhances the homing of cytokine-producing thymus-derived ILC1s to the liver and peritoneal cavity. Together, we show that type 1 immunity promotes the expansion and peripheral homing of thymic-derived ILC1s.

Loss of function of XBP1 splicing activity of IRE1α favors B cell tolerance breakdown

Anti-nuclear antibodies are the hallmark of autoimmune diseases such as systemic lupus erythematosus (SLE) and scleroderma. However, the molecular mechanisms of B cell tolerance breakdown in these pathological contexts are poorly known. The study of rare familial forms of autoimmune diseases could therefore help to better describe common biological mechanisms leading to B cell tolerance breakdown. By Whole-Exome Sequencing, we identified a new heterozygous mutation (p.R594C) in ERN1 gene, encoding IRE1α (Inositol-Requiring Enzyme 1α), in a multiplex family with several members presenting autoantibody-mediated autoimmunity. Using human cell lines and a knock-in (KI) transgenic mouse model, we showed that this mutation led to a profound defect of IRE1α ribonuclease activity on X-Box Binding Protein 1 (XBP1) splicing. The KI mice developed a broad panel of autoantibodies, however in a subclinical manner. These results suggest that a decrease of spliced form of XBP1 (XBP1s) production could contribute to B cell tolerance breakdown and give new insights into the function of IRE1α which are important to consider for the development of IRE1α targeting strategies.

Decoding immunogenic cell death from a dendritic cell perspective

Dendritic cells (DCs) are myeloid cells bridging the innate and adaptive immune system. By cross-presenting tumor-associated antigens (TAAs) liberated upon spontaneous or therapy-induced tumor cell death to T cells, DCs occupy a pivotal position in the cancer immunity cycle. Over the last decades, the mechanisms linking cancer cell death to DC maturation, have been the focus of intense research. Growing evidence supports the concept that the mere transfer of TAAs during the process of cell death is insufficient to drive immunogenic DC maturation unless this process is coupled with the release of immunomodulatory signals by dying cancer cells. Malignant cells succumbing to a regulated cell death variant called immunogenic cell death (ICD), foster a proficient interface with DCs, enabling their immunogenic maturation and engagement of adaptive immunity against cancer. This property relies on the ability of ICD to exhibit pathogen-mimicry hallmarks and orchestrate the emission of a spectrum of constitutively present or de novo-induced danger signals, collectively known as damage-associated molecular patterns (DAMPs). In this review, we discuss how DCs perceive and decode danger signals emanating from malignant cells undergoing ICD and provide an outlook of the major signaling and functional consequences of this interaction for DCs and antitumor immunity.

Canonical IRE1 function needed to sustain vigorous natural killer cell proliferation during viral infection

The unfolded protein response (UPR) aims to restore ER homeostasis under conditions of high protein folding load, a function primarily serving secretory cells. Additional, non-canonical UPR functions have recently been unraveled in immune cells. We addressed the function of the inositol-requiring enzyme 1 (IRE1) signaling branch of the UPR in NK cells in homeostasis and microbial challenge. Cell-intrinsic compound deficiency of IRE1 and its downstream transcription factor XBP1 in NKp46+ NK cells, did not affect basal NK cell homeostasis, or overall outcome of viral MCMV infection. However, mixed bone marrow chimeras revealed a competitive advantage in the proliferation of IRE1-sufficient Ly49H+ NK cells after viral infection. CITE-Seq analysis confirmed strong induction of IRE1 early upon infection, concomitant with the activation of a canonical UPR signature. Therefore, we conclude that IRE1/XBP1 activation is required during vigorous NK cell proliferation early upon viral infection, as part of a canonical UPR response.

The forgotten variable? Does the euthanasia method and sample storage condition influence an organisms transcriptome - a gene expression analysis on multiple tissues in pigs

BACKGROUND

Transcriptomic studies often require collection of fresh tissues post euthanasia. The chosen euthanasia method might have the potential to induce variations in gene expressions that are unlinked with the experimental design. The present study compared the suitability of 'nitrogen gas in foam' (ANOXIA) in comparison to a non-barbiturate anaesthetic, T-61® (T61), for euthanizing piglets used in transcriptome research. Further, the effect of common tissue storage conditions, RNAlater™ (RL) and snap freezing in liquid nitrogen (LN2), on gene expression profiles were also analysed.

RESULTS

On comparison of the 3'mRNA-Seq data generated from pituitary, hypothalamus, liver and lung tissues, no significant differential expression in the protein coding genes were detected between the euthanasia methods. This implies that the nitrogen anoxia method could be a suitable alternative for euthanasia of piglets used in transcriptomic research. However, small nuclear RNAs (snRNAs) that constitute the eukaryotic spliceosomal machinery were found to be significantly higher (log2fold change ≥ 2.0, and adjusted p value ≤ 0.1) in pituitary samples collected using ANOXIA. Non-protein coding genes like snRNAs that play an important role in pre-mRNA splicing can subsequently modify gene expression. Storage in RL was found to be superior in preserving RNA compared to LN2 storage, as evidenced by the significantly higher RIN values in representative samples. However, storage in RL as opposed to LN2, also influenced differential gene expression in multiple tissues, perhaps as a result of its inability to inhibit biological activity during storage. Hence such external sources of variations should be carefully considered before arriving at research conclusions.

CONCLUSIONS

Source of biological variations like euthanasia method and storage condition can confound research findings. Even if we are unable to prevent the effect of these external factors, it will be useful to identify the impact of these variables on the parameter under observation and thereby prevent misinterpretation of our results.

STE20 kinase TAOK3 regulates type 2 immunity and metabolism in obesity

Healthy adipose tissue (AT) contains ST2+ Tregs, ILC2s, and alternatively activated macrophages that are lost in mice or humans on high caloric diet. Understanding how this form of type 2 immunity is regulated could improve treatment of obesity. The STE20 kinase Thousand And One amino acid Kinase-3 (TAOK3) has been linked to obesity in mice and humans, but its precise function is unknown. We found that ST2+ Tregs are upregulated in visceral epididymal white AT (eWAT) of Taok3-/- mice, dependent on IL-33 and the kinase activity of TAOK3. Upon high fat diet feeding, metabolic dysfunction was attenuated in Taok3-/- mice. ST2+ Tregs disappeared from eWAT in obese wild-type mice, but this was not the case in Taok3-/- mice. Mechanistically, AT Taok3-/- Tregs were intrinsically more responsive to IL-33, through higher expression of ST2, and expressed more PPARγ and type 2 cytokines. Thus, TAOK3 inhibits adipose tissue Tregs and regulates immunometabolism under excessive caloric intake.

Association between age and inflammatory disease activity on magnetic resonance imaging in relapse onset multiple sclerosis during long-term follow-up

BACKGROUND AND PURPOSE

Inflammatory disease activity in multiple sclerosis (MS) decreases with advancing age. Previous work found a decrease in contrast-enhancing lesions (CELs) with age. Here, we describe the relation of age and magnetic resonance imaging (MRI) measures of inflammatory disease activity during long-term follow-up in a large real-world cohort of people with relapse onset MS.

METHODS

We investigated MRI data from the long-term observational Amsterdam MS cohort. We used logistic regression models and negative binomial generalized estimating equations to investigate the associations between age and radiological disease activity after a first clinical event.

RESULTS

We included 1063 participants and 10,651 cranial MRIs. Median follow-up time was 6.1 years (interquartile range = 2.4-10.9 years). Older participants had a significantly lower risk of CELs on baseline MRI (40-50 years vs. <40 years: odds ratio [OR] = 0.640, 95% confidence interval [CI] = 0.45-0.90; >50 years vs. <40 years: OR = 0.601, 95% CI = 0.33-1.08) and a lower risk of new T2 lesions or CELs during follow-up (40-50 years vs. <40 years: OR = 0.563, 95% CI = 0.47-0.67; >50 years vs. <40 years: OR = 0.486, 95% CI = 0.35-0.68).

CONCLUSIONS

Greater age is associated with a lower risk of inflammatory MRI activity at baseline and during long-term follow-up. In patients aged >50 years, a less aggressive treatment strategy might be appropriate compared to younger patients.

Nuanced role for dendritic cell intrinsic IRE1 RNase in the regulation of antitumor adaptive immunity

In cancer, activation of the IRE1/XBP1s axis of the unfolded protein response (UPR) promotes immunosuppression and tumor growth, by acting in cancer cells and tumor infiltrating immune cells. However, the role of IRE1/XBP1s in dendritic cells (DCs) in tumors, particularly in conventional type 1 DCs (cDC1s) which are cellular targets in immunotherapy, has not been fully elucidated. Here, we studied the role of IRE1/XBP1s in subcutaneous B16/B78 melanoma and MC38 tumors by generating loss-of-function models of IRE1 and/or XBP1s in DCs or in cDC1s. Data show that concomitant deletion of the RNase domain of IRE1 and XBP1s in DCs and cDC1s does not influence the kinetics of B16/B78 and MC38 tumor growth or the effector profile of tumor infiltrating T cells. A modest effect is observed in mice bearing single deletion of XBP1s in DCs, which showed slight acceleration of melanoma tumor growth and dysfunctional T cell responses, however, this effect was not recapitulated in animals lacking XBP1 only in cDC1s. Thus, evidence presented here argues against a general pro-tumorigenic role of the IRE1/XBP1s pathway in tumor associated DC subsets.

LXR signaling controls homeostatic dendritic cell maturation

Dendritic cells (DCs) mature in an immunogenic or tolerogenic manner depending on the context in which an antigen is perceived, preserving the balance between immunity and tolerance. Whereas the pathways driving immunogenic maturation in response to infectious insults are well-characterized, the signals that drive tolerogenic maturation during homeostasis are still poorly understood. We found that the engulfment of apoptotic cells triggered homeostatic maturation of type 1 conventional DCs (cDC1s) within the spleen. This maturation process could be mimicked by engulfment of empty, nonadjuvanted lipid nanoparticles (LNPs), was marked by intracellular accumulation of cholesterol, and was highly specific to cDC1s. Engulfment of either apoptotic cells or cholesterol-rich LNPs led to the activation of the liver X receptor (LXR) pathway, which promotes the efflux of cellular cholesterol, and repressed genes associated with immunogenic maturation. In contrast, simultaneous engagement of TLR3 to mimic viral infection via administration of poly(I:C)-adjuvanted LNPs repressed the LXR pathway, thus delaying cellular cholesterol efflux and inducing genes that promote T cell-mediated immunity. These data demonstrate that conserved cellular cholesterol efflux pathways are differentially regulated in tolerogenic versus immunogenic cDC1s and suggest that administration of nonadjuvanted cholesterol-rich LNPs may be an approach for inducing tolerogenic DC maturation.

Efficacy of CD40 Agonists Is Mediated by Distinct cDC Subsets and Subverted by Suppressive Macrophages

Agonistic αCD40 therapy has been shown to inhibit cancer progression in only a fraction of patients. Understanding the cancer cell-intrinsic and microenvironmental determinants of αCD40 therapy response is therefore crucial to identify responsive patient populations and to design efficient combinatorial treatments. Here, we show that the therapeutic efficacy of αCD40 in subcutaneous melanoma relies on preexisting, type 1 classical dendritic cell (cDC1)-primed CD8+ T cells. However, after administration of αCD40, cDC1s were dispensable for antitumor efficacy. Instead, the abundance of activated cDCs, potentially derived from cDC2 cells, increased and further activated antitumor CD8+ T cells. Hence, distinct cDC subsets contributed to the induction of αCD40 responses. In contrast, lung carcinomas, characterized by a high abundance of macrophages, were resistant to αCD40 therapy. Combining αCD40 therapy with macrophage depletion led to tumor growth inhibition only in the presence of strong neoantigens. Accordingly, treatment with immunogenic cell death-inducing chemotherapy sensitized lung tumors to αCD40 therapy in subcutaneous and orthotopic settings. These insights into the microenvironmental regulators of response to αCD40 suggest that different tumor types would benefit from different combinations of therapies to optimize the clinical application of CD40 agonists.

SIGNIFICANCE

This work highlights the temporal roles of different dendritic cell subsets in promoting CD8+ T-cell-driven responses to CD40 agonist therapy in cancer.

Baseline characteristics of patients with atrial fibrillation and cancer enrolled in the BLITZ-AF Cancer registry

Background

Evidences on atrial fibrillation (AF) in patients with cancer are limited, specifically with respect to antithrombotic therapy.

Methods

BLITZ-AF Cancer is a prospective, non-interventional study of the epidemiology and management of AF in patients with cancer. Patients were included from 112 cardiology units in Italy, Belgium, Netherlands, Spain, Portugal, and Ireland, based on the following criteria: age ≥18 years; documented cancer other than basal-cell or squamous-cell carcinoma of the skin diagnosed within 3 years; electrocardiographically confirmed AF within 1 year; no concomitant interventional study. Follow-up is ongoing.

Results

From June 26th, 2019 to Sep. 30th, 2021, 1,514 subjects were enrolled.

The most frequent cancer locations were lung (14.9%), colorectal (14.1%), breast (13.9%), prostate (8.8%), and non-Hodgkin lymphoma (8.1%); 463 (30.6%) of participants had metastases.

AF was first-detected in 323 (21.3%), paroxysmal in 460 (30.4%), persistent in 192 (12.7%), long-standing persistent in 33 (2.2%), and permanent in 506 (33.4%); 590 (39.0%) patients had symptoms attributable to AF.

Baseline characteristics are presented in Table 1. Males were more than women and almost half of the subjects was &gt;75 years-old. Cardiovascular risk factors were common and approximately 31% had heart failure or coronary artery disease. Previous thromboembolic and haemorrhagic events had occurred in 14% and 10% of subjects, respectively. The median CHA2DS2VASc score was 3.

As shown in Figure 1, the prescription of oral anticoagulants, especially direct-acting ones (DOACs), rose after the cardiology assessment, while the percentage of participants without any antithrombotic therapy declined.

Among 1,427 patients with non-valvular AF (i.e., no mitral stenosis or prosthetic mechanical valve), 997 (69.9%) were prescribed on DOACs at discharge/after consultation. At multivariable logistic regression analysis, variables associated with DOAC use were female sex (OR 1.58, 95% CI 1.22–2.05), age (OR 2.00, 95% CI 1.39–2.88 and OR 2.63, 95% CI 1.84–3.76, respectively, for 65–74 years and ≥75 years vs &lt;65 years), hypertension (OR 1.43, 95% CI 1.10–1.87), long-standing persistent or permanent AF (OR 1.36, 95% CI 1.05–1.78). Haemoglobin &lt;12 g/dL (OR 0.57, 95% CI 0.45–0.73), and planned cancer treatment (OR 0.72, 95% CI 0.57–0.92) were independently associated with a lower prescription of DOACs.

Conclusions

BLITZ-AF Cancer provides extensive information on a large, contemporary cohort of individuals with AF and cancer. This baseline snapshot indicates that cardiologists pursue the implementation of DOACs in these patients, although residual use of other antithrombotic therapies or lack of any thrombo-prophylaxis remains substantial.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): This study was supported by an unrestricted grant from Daiichi Sankyo.

Mortality and major adverse cardiac events in women with breast cancer receiving radiotherapy: a 10-year cohort study of patients and population controls

Background

Treatment for breast cancer (BC) frequently involves radiotherapy. Guidelines recommend screening for cardiac adverse events starting 10 years after radiotherapy. The rationale for recommending this interval is unclear and informed the objective of this study.

Objectives

Study cardiovascular event rates in the first decade following curative radiotherapy for breast cancer, the time frame before guidelines recommend screening.

Methods

We performed a monocentric, retrospective study enrolling all women with unilateral BC in 2007–2008, who received radiotherapy as part of their curative treatment. We compared event rates during 10 years follow-up with an age and risk factor-matched control population (FLEMENGHO population).

Results

We included 1095 BC patients (median age 55y, IQR: 47–66y). Two hundred and eighteen (19.9%) women died. Cancer and cardiovascular mortality accounted for 107 (49.1%) and 22 (10.1%) deaths, respectively. The incidence of coronary artery disease was similar compared to age and risk-matched women [risk ratio 0.75 (95% CI 0.48–1.18)], yet heart failure (HF) [risk ratio 1.97 (95% CI 1.19–3.25)] and atrial fibrillation or flutter (AF) (risk ratio 1.82 (95% CI 1.07–3.08) occurred more often. Age [HR 1.040 (95% CI 1.012–1.069)], tumor grade [HR 1.646 (95% CI 1.103–2.458)], and neo-adjuvant treatment setting [HR 3.079 (95% CI 1.432–6.620)] were risk factors for mortality; hormonal therapy [HR 0.007 (95% CI 0.001–0.042)] proved protective. Risk factors for MACE were mean heart dose [HR 1.079 (95% CI 1.012–1.151], hormonal therapy, history of cardiovascular disease [HR 2.771 (95% CI 1.253–6.126)], and Mayo Clinic Cardiotoxicity Risk Score [HR 2.547 (95% CI 1.538–4.217)]. While mean heart dose [HR 1.141 (95% CI 1.017–1.282)] and cardiovascular history [HR 3.374 (95% CI 1.259–9.043] clearly associated with new onset HF, only a trend towards higher AF burden with increasing mean heart dose could be observed.

Conclusions

Ten-year mortality following curative treatment for unilateral BC was mainly cancer-related. HF and AF constituted significantly increased risks in the first decade following irradiation. Mean heart dose, pre-existing cardiovascular diseases, and Mayo Clinic Cardiotoxicity Risk Score were risk factors for early cardiac mortality and adverse events and should guide early dedicated cardio-oncological follow-up.

Funding Acknowledgement

Type of funding sources: None.

Atherogenic lipoprotein profile associated with anthropometric indices of obesity and their association with cardiometabolic risk markers: a cross-sectional study in community

Background

Obesity, especially abdominal fat accumulation, is strongly associated with various metabolic comorbidities. Whether simple anthropometric measures are independently associated with atherogenic lipoproteins is not completely clear.

Methods

We randomly recruited 505 participants (51.5% women; mean age: 48.8 years) from the Flemish community, who had undergone lipoprotein particle measurements by nuclear magnetic resonance spectroscopy and conventional lipid measurements. Each lipoprotein fraction was subgrouped into large, medium, and small subclass. Anthropometric measures included body mass index (BMI) and waist-to-hip ratio (WHR), and defined BMI obesity as BMI ≥30 kg/m2, and WHR obesity as WHR ≥0.85 (women) or 0.9 (men).

Results

In the multivariable logistic regression analysis, total very-low-density lipoprotein (VLDL) particle and its subclasses were positively associated with BMI obesity (adjusted odds ratio [OR] for total VLDL: 2.37; 95% confidence interval [CI]: 1.70–3.31) and WHR obesity (OR for total VLDL: 2.06 [95% CI: 1.55–2.73]). The level of total high-density lipoprotein (HDL) particle and its subclass was negatively associated with BMI (OR for total HDL: 0.63 [95% CI: 0.45–0.90), but not with WHR (P≥0.11). None of the low-density lipoprotein (LDL) particles was associated with the two types of obesity (P≥0.092). BMI was inversely associated with the size of LDL and HDL particles, whereas high WHR was significantly associated with smaller VLDL and HDL sizes. For conventional lipid measures, both BMI and WHR were independently associated with high triglyceride and remnant cholesterol, both mainly driven from VLDL particles, and low HDL cholesterol (P≤0.008). These associations were confirmed in multivariable linear regression analysis, except the association of BMI with HDL number and the association of WHR with HDL size. With partial least squares analysis, the lipoprotein profiles of BMI and WHR were significantly associated with a high 10-year cardiovascular disease risk score, the homeostasis model assessment-estimated insulin resistance (HOMA-IR), and C-reactive protein.

Conclusion

BMI and WHR were independently associated with high triglyceride-rich lipoproteins, decreased HDL cholesterol. The size of LDL and HDL was more consistently associated with BMI than WHR. The lipoprotein alterations may link obesity with high cardiometabolic risk.

Funding Acknowledgement

Type of funding sources: Public grant(s) – EU funding. Main funding source(s): The European Research Council; the European Research Area Net for Cardiovascular Diseases

Association of fatal and non-fatal adverse health outcomes with urinary peptides reflecting collagen I turnover

Background

Imbalance of collagen I (COL1) turnover, featured by increased synthesis and decreased degradation of collagen fibers, is a hallmark of fibrosis in the heart and blood vessels that associates with poor cardiovascular outcomes. Such as imbalance of COL1 turnover could be reflected in urine and serve as fingerprint for future adverse outcomes in general population, and high risk subjects.

Purpose

We hypothesize that imbalance of proteomic signatures of urinary peptides (UPs) reflecting COL1 turnover relate to adverse health outcomes in participants from a general population

Methods

We randomly recruited 776 participants (51.2% women; 50.5 years) from the Flemish Study on Environment, Genes and Health Outcomes cohort and measured UPs proteome by capillary electrophoresis coupled with mass spectrometry. Our analyses focused on 148 peptides of COL1 alpha-1 (COL1A1) chain that retained ≥70% signal in the whole sample. The primary endpoint included fatal and nonfatal cardiovascular endpoints. Secondary endpoints consisted of total mortality, fatal and nonfatal cardiac, coronary, and heart failure endpoints. Multivariate Cox proportional models, partial least squares analysis (PLS), log-likelihood test, and receiver operating characteristics (ROC) curve were applied.

Results

Over a median follow up of 12.4 years, 110 primary endpoints occurred, 61 participants died, 81, 41 and 24 experienced cardiac, coronary, and heart failure endpoints; respectively. In PLS analyses, upregulation of UPs signatures closer to C- and N-terminal locations of the COL1A1 chain whereas downregulation of mid-region UPs were associated with lower risk of adverse health outcomes. This pattern was inverted in subjects with cardiovascular disease, as upregulation of terminal and downregulation of mid region UPs increased risk. Adding UPs to a basic model including sex, age and usual cardiovascular risk factors significantly improved model performance between 2.54% to 4.93% (P≤0.001) for prediction of adverse health outcomes. In ROC plots, adding UPs to the basic model increased the area under the curve up to 4.00% (P&lt;0.012).

Conclusions

UPs reflecting COL1 turnover predicted adverse health outcomes. The inverted up- and down regulations of UPs in between participants with and without previous cardiovascular diseases might be explained by a shift in the UPs signatures of COL1 fragments linked to distinct fibrotic processes. Urinary proteomic might have clinical importance in documenting the extent of collagen accumulation that relates to adverse health outcomes. In patients at high cardiovascular risk, modification of collagen I fibers turnover might be a potential treatment target

Funding Acknowledgement

Type of funding sources: Public grant(s) – EU funding. Main funding source(s): The European Union the European Research Council and the European Research Area Net for Cardiovascular Diseases.

Incidence of cardiovascular events in patients treated with immune checkpoint inhibitors

Background

In rare cases, immune checkpoint inhibitors (ICIs) cause immune-mediated myocarditis. However, the true incidence of other major adverse cardiovascular events (MACE) following ICI treatment remains unknown, mainly because late occurring side effects are rarely reported in prospective clinical trials.

Purpose

To identify the incidence and risk factors of MACE in a real-life ICI-treated cancer cohort and to compare the incidence with non-ICI-treated cancer patients and population controls.

Methods

In total, 672 ICI-treated patients were included. The primary endpoint was MACE, a composite of acute coronary syndrome, heart failure, stroke and transient ischemic attack. Secondary outcomes were acute coronary syndrome and heart failure separately. Incidence rates were compared between groups after matching according to age, sex, cardiovascular history and cancer type.

Results

Incidence of MACE was 10.3% during a median time of follow-up of 13 months (IQR 6 to 22). In multivariable analysis, a history of heart failure (hazard ratio (HR): 2.27; 95% confidence interval (CI): 1.03 to 5.04; p=0.043) and valvular heart disease (HR 3.01; 95% CI: 1.05 to 8.66; p=0.041) remained significantly associated with MACE.

Cumulative incidence rates were significantly higher in the matched ICI group (rate at full range of follow-up (rate): 8.51; 95% CI: 6.18 to 11.4) compared with the cancer cohort not exposed to ICI (rate: 5.20; 95% CI: 3.56 to 7.35; p=0.032) and the population controls (rate: 2.55; 95% CI: 2.16 to 2.99; p&lt;0.001) mainly driven by a higher risk of heart failure events (Figure 1).

Conclusions

Cardiovascular events during and after ICI treatment are more common than currently appreciated. Patients at risk are those with a history of cardiovascular disease. Compared with matched cancer and population controls, MACE incidence rates are significantly higher, suggesting a potential harmful effect of ICI treatment besides the underlying risk.

Funding Acknowledgement

Type of funding sources: None.

TIM3+ TRBV11-2 T cells and IFNγ signature in patrolling monocytes and CD16+ NK cells delineate MIS-C

In rare instances, pediatric SARS-CoV-2 infection results in a novel immunodysregulation syndrome termed multisystem inflammatory syndrome in children (MIS-C). We compared MIS-C immunopathology with severe COVID-19 in adults. MIS-C does not result in pneumocyte damage but is associated with vascular endotheliitis and gastrointestinal epithelial injury. In MIS-C, the cytokine release syndrome is characterized by IFNγ and not type I interferon. Persistence of patrolling monocytes differentiates MIS-C from severe COVID-19, which is dominated by HLA-DRlo classical monocytes. IFNγ levels correlate with granzyme B production in CD16+ NK cells and TIM3 expression on CD38+/HLA-DR+ T cells. Single-cell TCR profiling reveals a skewed TCRβ repertoire enriched for TRBV11-2 and a superantigenic signature in TIM3+/CD38+/HLA-DR+ T cells. Using NicheNet, we confirm IFNγ as a central cytokine in the communication between TIM3+/CD38+/HLA-DR+ T cells, CD16+ NK cells, and patrolling monocytes. Normalization of IFNγ, loss of TIM3, quiescence of CD16+ NK cells, and contraction of patrolling monocytes upon clinical resolution highlight their potential role in MIS-C immunopathogenesis.

Stress-induced inflammation evoked by immunogenic cell death is blunted by the IRE1α kinase inhibitor KIRA6 through HSP60 targeting

Mounting evidence indicates that immunogenic therapies engaging the unfolded protein response (UPR) following endoplasmic reticulum (ER) stress favor proficient cancer cell-immune interactions, by stimulating the release of immunomodulatory/proinflammatory factors by stressed or dying cancer cells. UPR-driven transcription of proinflammatory cytokines/chemokines exert beneficial or detrimental effects on tumor growth and antitumor immunity, but the cell-autonomous machinery governing the cancer cell inflammatory output in response to immunogenic therapies remains poorly defined. Here, we profiled the transcriptome of cancer cells responding to immunogenic or weakly immunogenic treatments. Bioinformatics-driven pathway analysis indicated that immunogenic treatments instigated a NF-κB/AP-1-inflammatory stress response, which dissociated from both cell death and UPR. This stress-induced inflammation was specifically abolished by the IRE1α-kinase inhibitor KIRA6. Supernatants from immunogenic chemotherapy and KIRA6 co-treated cancer cells were deprived of proinflammatory/chemoattractant factors and failed to mobilize neutrophils and induce dendritic cell maturation. Furthermore, KIRA6 significantly reduced the in vivo vaccination potential of dying cancer cells responding to immunogenic chemotherapy. Mechanistically, we found that the anti-inflammatory effect of KIRA6 was still effective in IRE1α-deficient cells, indicating a hitherto unknown off-target effector of this IRE1α-kinase inhibitor. Generation of a KIRA6-clickable photoaffinity probe, mass spectrometry, and co-immunoprecipitation analysis identified cytosolic HSP60 as a KIRA6 off-target in the IKK-driven NF-κB pathway. In sum, our study unravels that HSP60 is a KIRA6-inhibitable upstream regulator of the NF-κB/AP-1-inflammatory stress responses evoked by immunogenic treatments. It also urges caution when interpreting the anti-inflammatory action of IRE1α chemical inhibitors.

Risk of contamination of semen, vaginal secretions, follicular fluid and ovarian medulla with SARS-CoV-2 in patients undergoing ART

STUDY QUESTION

Can severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) mRNA be detected in the reproductive tract of asymptomatic patients undergoing ART?

SUMMARY ANSWER

SARS-CoV-2 mRNA is not detectable in semen, follicular fluid, vaginal secretions or residual medulla from ovarian tissue cryopreservation procedures in asymptomatic patients who undergo ART, irrespective of the results of a triage questionnaire and a nasopharyngeal SARS-CoV-2 RNA detection test.

WHAT IS KNOWN ALREADY

The SARS-CoV-2 pandemic had a huge impact on the activities of fertility clinics. Although some studies reported the presence of SARS-CoV-2 mRNA in the reproductive system during or after acute COVID-19 symptomatic infections, uncertainties remain regarding the presence of viral mRNA in the reproductive material and follicular fluid of asymptomatic patients undergoing ART.

STUDY DESIGN, SIZE, DURATION

An observational cohort trial of residual material samples including semen, follicular fluid, vaginal secretions and ovarian medulla was conducted during the second pandemic wave in Brussels from September 2020 to April 2021.

PARTICIPANTS/MATERIALS, SETTING, METHODS

All patients who underwent ART (IUI, IVF/ICSI, oocyte and ovarian tissue cryopreservation) responded to a triage questionnaire at the beginning and end of the cycle and underwent nasopharyngeal swab collection for SARS-CoV-2 RNA detection by RT-PCR before the procedure according to standard recommendations. For semen analysis, only the questionnaire was requested the day before the sample collection. The ART cycles of patients with positive nasopharyngeal SARS-CoV-2 RNA detection tests and/or questionnaires were cancelled except for those that could not be postponed. After providing informed consent, swabs on residual materials were collected the day of the oocyte, ovarian tissue or semen collection and were processed for RT-qPCR.

MAIN RESULTS AND THE ROLE OF CHANCE

A total of 394 samples from 291 patients were analysed. Amongst them, 20 samples were obtained from patients with a positive questionnaire but negative nasopharyngeal SARS-CoV-2 test and 20 others were from patients with a positive nasopharyngeal SARS-CoV-2 test. The remaining samples were collected from patients with a negative or unknown nasopharyngeal SARS-CoV-2 test and/or a negative or unknown triage questionnaire. Viral RNA for SARS-CoV-2 was undetectable in all of the samples.

LIMITATIONS, REASONS FOR CAUTION

Considering the cancellation policy, only a limited number of samples from patients with positive triage questionnaires or nasopharyngeal SARS-CoV-2 tests were included in the analysis.

WIDER IMPLICATIONS OF THE FINDINGS

The study suggested that there was no risk of reproductive tract contamination by SARS-CoV-2 in asymptomatic patients, irrespective of the results from a triage questionnaire or nasopharyngeal SARS-CoV-2 test. The results suggested that no additional measures to prevent staff or cross-patient contamination need to be implemented in the IVF and andrology laboratories.

STUDY FUNDING/COMPETING INTEREST(S)

This study was funded by the Université Libre de Bruxelles and by a grant from Ferring. A.D. and I.D. received a grant from Ferring for the study. The authors have no other conflict of interest to declare related to this study.

TRIAL REGISTRATION NUMBER

N/A.

Screening for antibodies against the sheep scab mite (Psoroptes ovis) Pso o 2 antigen in experimentally infested Swifter sheep may fail to identify affected animals

Sheep scab, caused by Psoroptes ovis mites, represents a significant threat to sheep health and welfare. Infestations are diagnosed by parasite identification in skin scrapings, and more recently with a commercial ELISA against serum antibodies to the Pso o 2 mite allergen. However, little is known about the performance of the ELISA in non-UK sheep populations. In this study, six Swifter sheep were experimentally infested with P. ovis. Lesion sizes were monitored and serum IgG against Pso o 2 and the novel Pso-EIP-1 antigens were measured by ELISA. Although all sheep showed signs of infestation, serum from two animals failed to react with Pso o 2. However, they did react to Pso-EIP-1. This indicates that cases of sheep scab in (Swifter) sheep may remain undetected using the Pso o 2 ELISA, which may have implications for routine screening of non- UK sheep breeds.

The novel proteomic signature for the detection of cardiac allograft vasculopathy

Background

Cardiac allograft vasculopathy (CAV) is the major long-term complications after heart transplantation, leading to mortality and re-transplantation. As available noninvasive biomarkers are scarce for CAV screening, we aimed to identify a proteomic signature for CAV detection.

Methods

Urinary proteome was measured by capillary electrophoresis coupled to mass spectrometry in 217 heart transplantation recipients. Participants were further randomly and evenly divided into the derivation cohort and validation cohort. The proteomic signature for CAV was identified by decision tree-based machine learning in the derivation cohort and further tested in the validation cohort. The pathway analysis was investigated with Reactome Pathway Database.

Results

We identified a proteomic signature with 27 urinary peptides, which yielded areas under the curve (AUC) of 0.83 and 0.71 in the derivation and validation cohort, respectively. In the validation cohort, it had a sensitivity of 68.4%, specificity of 73.2%, accuracy of 71.6%, negative predictive value of 81.3%. Including the proteomic signature into the basic model further improved the diagnostic accuracy with an relative integrated discrimination improvement of 25.9% and the continuous net reclassification improvement of 83.3% (p≤0.023). The pathways analysis on revealed that collagen turnover, platelet aggregation and coagulation, cell adhesion and motility might involve in the pathogenesis of CAV.

Conclusions

The proteomic signature might be valuable for the surveillance of CAV thereby reduce the frequency of invasive procedures after HTx. Moreover, the highlighted pathways might provide insights in the potential novel treatment targets for CAV.

Funding Acknowledgement

Type of funding sources: Public grant(s) – EU funding. Main funding source(s): European Research Council Advanced Researcher Grant and Proof-of-Concept Grant ROC curves of the urinary proteomicThe 25 highlighted enrichment pathways

Targeted delivery controlled release of hepatic growth factor and insulin-like growth factor-1 improves left ventricular repair in a porcine model of myocardial ischemia reperfusion injury

Introduction

Nanomedicine offers great potential for treatment of cardiovascular disease. We tested whether direct intramyocardial (IM) injection of pro-angiogenic hepatocyte growth factor (HGF) and pro-myogenic insulin-like growth factor (IGF-1) encapsulated in Alginate-Sulfate nanoparticles (AlgS-NP) enhances myocardial retention, controlled release and improves myocardial repair in a porcine ischemia-reperfusion model.

Methods

Bioactivity of HGF/IGF, released from AlgS-NP, was determined by cell proliferation assays in vitro. Myocardial infarction (MI) was induced by 75min balloon occlusion of the mid-LAD followed by reperfusion. After 1w, pigs (n=12) with marked LV dysfunction (EF&lt;45%) were randomized to fusion imaging-guided IM injections of 8 mg Cy5-labelled AlgS-NP loaded with 200μg HGF and 200μg IGF-1 (GF) or with phosphate-buffered saline (CON) using the MYOSTAR injection catheter. AlgS-NP retention after IM or intracoronary (IC) injection was determined by measuring Cy5 plasma levels. At 8w, treatment effect was evaluated using in vivo magnetic resonance imaging and coronary physiological measurements, and via post-mortem analysis of myocardial fibrosis and cardiomyocyte circumference.

Results

We confirmed the bioactivity of the AlgS-NP-released GF in C2C12 and HUVEC cell proliferation assays after 72h culture, being similar to the free GF (Fig. A). AlgS-NP retention was tested in a pig model, 1w after MI. Ejection fraction (EF) was 37±5% (range 27–45%) and infarct size (IS)/LVmass 24±6% (range 19–38%). AlgS-NP retention was better after IM delivery than after IC infusion with plasma Cy5 levels at 30 min after treatment indicating 5% systemic leakage for IM vs. 20% for IC. After 8w, IS/LVmass decreased 8% in GF-treated pigs vs. 3% in CON (P=0.03, Fig. B) and was associated with preserved myocardial blood flow during hyperemia in the infarct (P=0.036) and peri-infarct (PI) zones (P=0.008), increased coronary flow reserve (P=0.05) and decreased index of microcirculatory resistance (P=0.02). LVEF significantly increased in GF-treated pigs (+6±2% vs. −1±1% in CON, P=0.02, Fig. C), and was accompanied by significantly reduced fibrosis (P=0.01) and increased hypertrophy of cardiomyocyte (P=0.03) in the PI zone.

Conclusions

IM injection of AlgS-NP-encapsulated HGF and IGF-1 to the ischemic myocardium significantly improves LV repair, and offers the prospect of innovative treatment for patients with refractory ischemic heart disease.

Funding Acknowledgement

Type of funding sources: Public grant(s) – EU funding. Main funding source(s): EuroNanoMed II Figure AFigure B and C

The urinary proteomic profile of arterial stiffness in the general population

Background

Although arterial stiffness is an independent predictor of cardiovascular outcomes, its physiopathology remains unclear.

Purpose

This study aimed to investigate the urinary proteomic profile of aortic stiffness and provide insights into pathogenetic processes of arterial stiffness by pathway analysis.

Methods

In 669 participants (mean age, 50.5 years; 48.9% men) randomly recruited from the Flemish population, we measured carotid-femoral pulse wave velocity (PWV) by applanation tonometry. The proteomics of urine samples was quantified by using capillary electrophoresis coupled mass spectrometry. The proteomic data were analysed by the orthogonal projections to latent structures, a supervised dimensional reduction statistic method and summarised as a urinary proteomic (UP) score.

Results

The mean values were 7.56±2.02 m/s for PWV and 7.59±1.95 unit for the UP score. PWV was significantly associated with the UP score before and after adjustment for the potential covariates (β coefficient: 0.81 and 0.75, respectively; p&lt;0.001). The significant proteins in the urinary proteomic profile consisted of 43 kinds of proteins, including collagen I, II and III, fibrinogen, matrix Gla-protein, apolipoprotein A-I and A-VI. The pathways annotated by the significant proteins mainly involved in fibrosis, signal conduction, platelet activation and aggregation.

Conclusions

In conclusion, the urinary proteomic profile could be a new biomarker of aortic stiffness and the altered proteins may link to the underlying mechanisms and holds the potential to discover novel therapeutic targets for arterial stiffness.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): The Internal Funds KU Leuven (STG-18-00379) Distribution and CorrelationThe Enrichment Pathways

Predictability of cardiotoxicity at a Belgian cardio-oncology clinic without mandatory physician referral

Background and purpose

Increased morbidity and mortality caused by side-effects of cancer treatment on cardiovascular function mandates careful monitoring and shared decision-making in cardio-oncology clinics. We report the experience of the cardio-oncology clinic at a large Belgian tertiary care center, without mandatory physician referral, and investigated the predictability of cardiotoxicity based on pre-existing cardiovascular risk factors, specific cancer treatment and existing risk scores of the American Society of Clinical Oncology (ASCO) and Mayo Clinic.

Methods

We included all patients seen at the outpatient cardio-oncology clinic between May 2018 and September 2020. We defined cardiotoxicity as a decline in ejection fraction (EF) of 10% in asymptomatic patients and 5% in symptomatic patients. Approval of the ethical committee was obtained (S65084).

Results

The majority were women (68%), with almost half (44%) having metastatic disease. Mean age was 63.4±16.0 years. The most frequent oncological diagnoses were breast cancer (33%) and haematological diseases (24%). Patients most frequently received radiation therapy (42%), anthracyclines (39%) and antimetabolites (35%). Mean follow-up was 443±245 days.

Receiver operating characteristic (ROC) analysis of predictors of cardiotoxicity showed an area under the curve (AUC) of 0.580 (CI 95% bootstrap: 0.525–0.642) for cardiovascular risk factors alone, and an AUC of 0.613 (CI 95% bootstrap: 0.550–0.676) when treatment was added to the model. The ASCO risk score poorly predicted cardiotoxicity (sensitivity 64%, specificity 52%). The Mayo Clinic cardiotoxicity risk score was the best predictor of cardiotoxicity with an AUC of 0.685 (CI 95% bootstrap: 0.625–0.743).

Discussion

Classic cardiovascular risk factors alone, or in combination with the proposed cancer treatment cannot adequately predict cardiotoxicity risk. The Mayo Clinic Cardiotoxicity Risk score outperformed the ASCO risk score but requires further refinement to enhance adequate cardiovascular risk prediction. For future model building, we hypothesize that an all-comer population of oncological patients should be used as a derivation cohort, regardless of previous or current cardiac issues, risk factors or type of therapy. Admittedly, individual susceptibility due to genetic, epigenetic and environmental predisposition cannot be adequately incorporated into a risk score and emphasizes the need for individual cardiotoxicity risk evaluation using bed to bench tools such as the use of induced pluripotent stem cell derived cardiac or vascular cells to assess the susceptibility of individual patients to cancer drug-induced cardiovascular toxicities. In the absence of adequate risk prediction tools, we advocate standardized screening of all patients before oncological treatment starts.

Funding Acknowledgement

Type of funding sources: None. Figure 1. Cardiotoxicity

A20 deficiency in myeloid cells protects mice from diet-induced obesity and insulin resistance due to increased fatty acid metabolism

Obesity-induced inflammation is a major driving force in the development of insulin resistance, type 2 diabetes (T2D), and related metabolic disorders. During obesity, macrophages accumulate in the visceral adipose tissue, creating a low-grade inflammatory environment. Nuclear factor κB (NF-κB) signaling is a central coordinator of inflammatory responses and is tightly regulated by the anti-inflammatory protein A20. Here, we find that myeloid-specific A20-deficient mice are protected from diet-induced obesity and insulin resistance despite an inflammatory environment in their metabolic tissues. Macrophages lacking A20 show impaired mitochondrial respiratory function and metabolize more palmitate both in vitro and in vivo. We hypothesize that A20-deficient macrophages rely more on palmitate oxidation and metabolize the fat present in the diet, resulting in a lean phenotype and protection from metabolic disease. These findings reveal a role for A20 in regulating macrophage immunometabolism.

The effect of fluid bolus administration on cerebral tissue oxygenation in post-cardiac arrest patients

PURPOSE

Fluid boluses (FB) are often used in post-cardiac arrest (CA) patients with haemodynamic instability. Although FB may improve cardiac output (CO) and mean arterial pressure (MAP), FB may also increase central venous pressure (CVP), reduce arterial PaO₂, dilute haemoglobin and cause interstitial oedema. The aim of the present study was to investigate the net effect of FB administration on cerebral tissue oxygenation saturation (SctO₂) in post-CA patients.

METHODS

Pre-planned sub-study of the Neuroprotect post-CA trial (NCT02541591). Patients with anticipated fluid responsiveness based on stroke volume variation (SVV) or passive leg raising test were administered a FB of 500 ml plasma-lyte A (Baxter Healthcare) and underwent pre- and post-FB assessments of stroke volume, CO, MAP, CVP, haemoglobin, PaO₂ and SctO₂.

RESULTS

52 patients (mean age 64 ± 12 years, 75% male) received a total of 115 FB. Although administration of a FB resulted in a significant increase of stroke volume (63 ± 22 vs 67 ± 23 mL, p = 0.001), CO (4,2 ± 1,6 vs 4,4 ± 1,7 L/min, p = 0.001) and MAP (74,8 ± 13,2 vs 79,2 ± 12,9 mmHg, p = 0.004), it did not improve SctO₂ (68.54 ± 6.99 vs 68.70 ± 6.80%, p = 0.49). Fluid bolus administration also resulted in a significant increase of CVP (10,0 ± 4,5 vs 10,7 ± 4,9 mmHg, p = 0.02), but did not affect PaO₂ (99 ± 31 vs 94 ± 31 mmHg, p = 0.15) or haemoglobin concentrations (12,9 ± 2,1 vs 12,8 ± 2,2 g/dL, p = 0.10). In a multivariate model, FB-induced changes in CO (beta 0,77; p = 0.004) and in CVP (beta -0,23; p = 0.02) but not in MAP (beta 0,02; p = 0.18) predicted post-FB ΔSctO₂.

CONCLUSIONS

Despite improvements in CO and MAP, FB administration did not improve SctO₂ in post-cardiac arrest patients.

The STE20 kinase TAOK3 controls the development house dust mite-induced asthma in mice

BACKGROUND

The most common endotype of asthma is type 2-high asthma, which is sometimes driven by adaptive allergen-specific T_H2 lymphocytes that react to allergens presented by dendritic cells (DCs), or sometimes by an innate immune response dominated by type 2 innate lymphocytes (ILC2s). Understanding the underlying pathophysiology of asthma is essential to improve patient-tailored therapy. The STE20 kinase thousand-and-one kinase 3 (TAOK3) controls key features in the biology of DCs and lymphocytes, but to our knowledge, its potential usefulness as a target for asthma therapy has not yet been addressed.

OBJECTIVE

We examined if and how loss of Taok3 affects the development of house dust mite (HDM)-driven allergic asthma in an in vivo mouse model.

METHODS

Wild-type Taok3^+/+ and gene-deficient Taok3^-/- mice were sensitized and challenged with HDM, and bronchoalveolar lavage fluid composition, mediastinal lymph node cytokine production, lung histology, and bronchial hyperreactivity measured. Conditional Taok3^fl/fl mice were crossed to tissue- and cell-specific specific deletor Cre mice to understand how Taok3 acted on asthma susceptibility. Kinase-dead (KD) Taok3^KD mice were generated to probe for the druggability of this pathway. Activation of HDM-specific T cells was measured in adoptively transferred HDM-specific T-cell receptor-transgenic CD4⁺ T cells. ILC2 biology was assessed by in vivo and in vitro IL-33 stimulation assays in Taok3^-/- and Taok3^+/+, Taok3^KD, and Red5-Cre Taok3^fl/fl mice.

RESULTS

Taok3^-/- mice failed to mount salient features of asthma, including airway eosinophilia, T_H2 cytokine production, IgE secretion, airway goblet cell metaplasia, and bronchial hyperreactivity compared to controls. This was due to intrinsic loss of Taok3 in hematopoietic and not epithelial cells. Loss of Taok3 resulted in hampered HDM-induced lung DC migration to the draining lymph nodes and defective priming of HDM-specific T_H2 cells. Strikingly, HDM and IL-33-induced ILC2 proliferation and function were also severely affected in Taok3-deficient and Taok3^KD mice.

CONCLUSIONS

Absence of Taok3 or loss of its kinase activity protects from HDM-driven allergic asthma as a result of defects in both adaptive DC-mediated T_H2 activation and innate ILC2 function. This identifies Taok3 as an interesting drug target, justifying further testing as a new treatment for type 2-high asthma.

P–795 Assessment of the risk of contamination of semen, follicular and vaginal fluids with SARS-CoV–2 virus in patients undergoing ART

Study question

Is SARS-CoV–2 detected by RT-PCR in the reproductive materials and follicular fluid of asymptomatic patients undergoing fertility treatments?

Summary answer

No SARS-CoV–2 mRNA was detected in sperm, vaginal and follicular fluids samples of asymptomatic patients, irrespective of the nasopharyngeal swab or COVID–19 questionnaire results. What is known already: The COVID–19 pandemic had a huge impact on health care including on fertility clinics. While activities were interrupted during the first wave, ART cycles are currently performed but uncertainties remain regarding the presence of the virus in reproductive materials. The SARS-CoV–2 receptors were detected in reproductive organs but only few studies with limited number of cases reported the presence of SARS-CoV–2mRNA in semen of symptomatic patients. In women, the risk of SARS-CoV–2 contamination in follicular and vaginal fluids remains uncertain. Thus the risk of sexual transmission and the safety of the IVF laboratory procedures are unclear.

Study design, size, duration

This COVART study is an observational cohort prospective trial conducted at a Belgian academic hospital. Between September 2020 and January 2021, 208 asymptomatic adults patients (men and women) undergoing ART treatments (sperm analysis, IUI, ICSI/ICF cycles, oocyte cryopreservation) were included in the trial after informed consent. All patients followed standard procedures to evaluate COVID–19 risk (nasopharyngeal swab during ovarian stimulation and COVID–19 risk questionnaire). Participants were divided into two groups: COVID–19 positive and negative/unknown groups. Participants/materials, setting, methods: Swabs on the residual reproductive materials were done and stored in viral transport medium at 4 °C until processing. After addition of an internal control in each sample and virus inactivation with Trizol, mRNA was extracted using phenol-chloroform method. Quantitative RT-PCR was performed in duplicate following a previously validated protocol (45 cycles, Roche Light Cycler 480). Negative/positive controls were used to validate each run. The test was considered as positive when CT &lt; 40.

Main results and the role of chance

A total of 399 samples (126 semen, 162 vaginal fluid, 111 follicular fluid samples) of reproductive residual materials from 208 participants were collected during the peak of the second wave of COVID–19 pandemic, when Belgium was considered as a red zone with a viral Rt of 1.516 and a 14-day COVID–19 cases notification rate above 630 per 100000. Although the policy of the fertility clinic was to cancel all cycles of patients with a positive nasopharyngeal swab test except if specific medical raisons to continue the cycle, 14 samples from 9 non-cancelled patients diagnosed with COVID–19 before or just after the samples collection were analyzed (4 sperm, 5 follicular fluid and 5 vaginal secretion samples). For the 199 remaining patients, the COVID–19 status was negative or unknown. None of the samples were considered as positive after quantitative RT-PCR analysis.

Limitations, reasons for caution

All the patients were asymptomatic at the time of the samples collection and the large majority was negatively diagnosed for COVID–19 during the ART cycle. The results should be confirmed by including a larger cohort of positive patients. Data on the impact on ART outcomes will be evaluated.

Wider implications of the findings: We showed that contaminations of sperm, follicular and vaginal fluids with SARS-CoV–2 are unlikely in asymptomatic patients, even when diagnosed positive, confirming the poor risk of sexual transmission. Moreover, no additional safety measures seems to be implemented in the IVF laboratory to ensure the safety of the staff.

Trial registration number

P2020/414

Evolution of muscle strength and physical activity 1 year after heart transplantation: a prospective observational study

Funding Acknowledgements

Type of funding sources: None.

Background

Heart transplantation (HTX) is a therapeutic option in a selected group of patients with end-stage heart failure. Although cardiac function normalizes after surgery, maximal exercise capacity of HTX-patients after 1 year is only half that of age- and gender matched healthy subjects. Data on the evolution of muscle strength and physical activity after HTX are scant. Having this knowledge might help to optimize rehabilitation programs.

Purpose

To describe changes in muscle strength and physical activity following HTX.

Methods

58 HTX-patients were addressed, of whom 52 (90%) patients participated in the study. Study visits were planned every 3 months from hospital discharge until 1 year of follow-up. 43 HTX-patients (67% male; age: 48 ± 14 years; BMI: 24 ± 4 kg/m²) fulfilled the study protocol. Outcome measures included functional exercise capacity (6MWD), peripheral strength (QF), respiratory muscle strength (MIP) and objectively measured physical activity (PAwalk, walking intensity (WI), PAsteps). All patients received physiotherapy at home during the first 6 weeks, as standard of care after thoracic surgery. After that, cardiac rehabilitation in a specialized center was started. Data were analyzed using repeated measures ANOVA, with Bonferroni test as post-hoc test.

Results

6MWD (+178 ± 17 meter), QF (+26 ± 4 Nm) and MIP (-32 ± 3 cmH2O) significantly improved over time (p &lt; 0.0001). Despite improvements in QF, peripheral muscle weakness was still present in 32% of patients 1 year post-HTX. A significant time effect in PA (PAwalk (+33 ± 7 minutes/day), WI (+0.036 ± 0.007 g) and PAsteps (+3711 ± 640 steps/day)) could be noticed (p &lt; 0.0001). Sedentary time did not significantly change during follow-up (p = 0.14). (Figure 1)

Conclusion

Functional exercise capacity and muscle strength gradually improve during 1 year after HTX. A considerable number of patients still present with peripheral muscle weakness. Despite improvements in PA, results remain below recommended health levels. Enrollment in a cardiac rehabilitation program, offering a combined exercise and PA intervention seems warranted to further enhance health outcomes in this patient population.

Abstract Figure 1

Molecular Evaluation of Endoplasmic Reticulum Homeostasis Meets Humoral Immunity

The biosynthesis of about one third of the human proteome, including membrane receptors and secreted proteins, occurs in the endoplasmic reticulum (ER). Conditions that perturb ER homeostasis activate the unfolded protein response (UPR). An 'optimistic' UPR output aims at restoring homeostasis by reinforcement of machineries that guarantee efficiency and fidelity of protein biogenesis in the ER. Yet, once the UPR 'deems' that ER homeostatic readjustment fails, it transitions to a 'pessimistic' output, which, depending on the cell type, will result in apoptosis. In this article, we discuss emerging concepts on how the UPR 'evaluates' ER stress, how the UPR is repurposed, in particular in B cells, and how UPR-driven counter-selection of cells undergoing homeostatic failure serves organismal homeostasis and humoral immunity.

The UPR sensor IRE1α promotes dendritic cell responses to control Toxoplasma gondii infection

The unfolded protein response (UPR) has emerged as a central regulator of immune cell responses in several pathologic contexts including infections. However, how intracellular residing pathogens modulate the UPR in dendritic cells (DCs) and thereby affect T cell-mediated immunity remains uncharacterized. Here, we demonstrate that infection of DCs with Toxoplasma gondii (T. gondii) triggers a unique UPR signature hallmarked by the MyD88-dependent activation of the IRE1α pathway and the inhibition of the ATF6 pathway. Induction of XBP1s controls pro-inflammatory cytokine secretion in infected DCs, while IRE1α promotes MHCI antigen presentation of secreted parasite antigens. In mice, infection leads to a specific activation of the IRE1α pathway, which is restricted to the cDC1 subset. Mice deficient for IRE1α and XBP1 in DCs display a severe susceptibility to T. gondii and succumb during the acute phase of the infection. This early mortality is correlated with increased parasite burden and a defect in splenic T-cell responses. Thus, we identify the IRE1α/XBP1s branch of the UPR as a key regulator of host defense upon T. gondii infection.

On-farm prevalence of and potential risk factors for boar taint

Boar taint is an unpleasant taste and odor that can occur in entire male pigs and is caused by androstenone, skatole, and to a lesser extent indole accumulating in fat tissue. In the present observational study, we evaluated an extensive list of such potential risk factors which influence boar taint: social hierarchy and puberty attainment, housing, health, preslaughter conditions, season, feed, carcass composition, slaughter weight or age, and breed. Details on these factors were collected by interviews with the participating farmers, observations on each farm by trained observers and farmers, as well as slaughterhouse data. Twenty-two farms (in West- and East-Flanders, ranging from 160 to 600 sows, selected on suitability) raising entire male pigs were included in the study to evaluate the link between boar taint and potential risk factors related to the farm and slaughter batch (114 slaughter batches and 16 791 entire male pigs in total). Average olfactory boar taint prevalence was 1.8 ± 0.8%. Boar taint prevalence varied also within farms up to a maximum range between slaughter batches of 9.1% which suggests an effect of factors varying between slaughter batches such as season or other variables varying between slaughter batches. Less aggressive behavior at the end of fattening as well as lower skin lesion scores at fattening as well as at slaughter could be associated with less boar taint. The same might be said for sexual behavior, though less convincingly from this study. Measures that reduce aggression and stress have therefore have the potential to lower boar taint prevalence. The same might be said for sexual behavior, though less convincingly from this study. Furthermore, boar taint prevalence was generally higher in winter than in summer, which is relevant from a planning perspective for the slaughterhouses to seek alternative markets. Finally, increased CP gave significantly lower boar taint prevalences. This may to some extent be explained by the negative association between boar taint and lean meat percentage, as increased dietary CP levels promote the carcass lean meat percentages which can then be associated with lower boar taint levels.

Optimal antithrombotic regimen in patients with cardiogenic shock on ImpellaTM mechanical support: less might be more

Background

Bleeding and ischemic complications are the main cause of morbidity and mortality in critically ill cardiogenic shock patients, supported by short-term percutaneous mechanical circulatory support (pMCS) devices. Hence, finding the optimal antithrombotic regimen is challenging. Bleeding not only occurs because of heparin and antiplatelet therapy (both required in the prevention of pump and acute stent thrombosis) but also because of device- and disease related coagulopathy. To prevent clotting-related device failure, most centers target full therapeutic heparin anticoagulation levels in left ventricular (LV) Impella™ supported patients in analogy with Veno-Arterial Extracorporeal Membrane Oxygenation. We aimed to investigate the safety (related to bleeding and thrombotic complications) of targeting low-dose versus therapeutic heparin levels in left Impella™-supported cardiogenic shock patients on dual antiplatelet therapy (DAPT).

Methods

In this hypothesis generating pilot study, we investigated 114 patients supported for at least two days by LV Impella™ mechanical support due to cardiogenic shock at three tertiary ICUs, highly specialized in mechanical support. Low-dose heparin (aPTT 40–60s or anti-Xa 0.2–0.3) was compared to standard of care (aPTT 60–80s or anti-Xa 0.3–0.5). Major adverse cardio- and cerebrovascular events (MACCE; composite of death, myocardial infarction, stroke/transient ischemic attack) and BARC bleeding (bleeding academic research consortium classification) during 30 day follow-up were assessed. Inverse probability of treatment weighting (IPTW) analysis was calculated with age, gender, arterial hypertension, diabetes mellitus, smoking, chronic kidney disease, previous stroke, previous myocardial infarction, previous coronary arterial bypass grafting, hypercholesterolemia and DAPT as matching variables. COX regression analysis was conducted to test for robustness.

Results

IPTW revealed 52 patients in the low-dose heparin group and 62 patients in the therapeutic group. Mean age of patients after IPTW was 62±16 years in the intermediate and 62±13 years in the therapeutic group (p=0.99). 25% and 42.2% were male (p=0.92). Overall bleeding events and major (BARC3b) bleeding events were higher in the therapeutic heparin group (overall bleeding: Hazard ratio [HR]=2.58, 95% confidence interval [CI] 1.2–5.5; p=0.015; BARC 3b: HR=4.4, 95% CI 1.4–13.6, p=0.009). Minor bleeding (BARC3a) as well as MACCE and its single components (ischemic events) did not differ between both groups. These findings were robust in the COX regression analysis.

Conclusion

In this pilot analysis, low-dose heparin in 114 LV Impella™ cardiogenic shock patients was associated with less bleeding without increased ischemic events, adjusted for DAPT. Reducing the target heparin levels in critically ill patients supported by LV Impella™ might improve the outcome of this precarious group. These findings need to be validated in randomized clinical trials.

Funding Acknowledgement

Type of funding source: None

Left heart Impella-device to bridge acute mitral regurgitation to MitraClip-procedure: a novel implementation of percutaneous mechanical circulatory support

Background

Acute mitral regurgitation (MR) is an emergency, often requiring urgent surgery. Severe acute MR presenting with hemodynamic collapse is usually caused by papillary muscle rupture or dysfunction after acute myocardial infarction (AMI) or chordal rupture, resulting in flail mitral leaflet(s). Preoperative stabilization is complex due to concomitant hemodynamic collapse and hypoxic respiratory failure. Finding the right balance between both preload and inotropic support is challenging. When patients are too sick for immediate surgical intervention, mechanical circulatory support can be considered because of its ability to both unload and reduce of cardiac work while increasing coronary perfusion and cardiac output. Nevertheless, even after initial stabilization, surgical risk remains high in critically ill acute severe MR patients and transcatheter treatments such as MitraClip are increasingly being explored.

Methods

Between August 2017 and September 2019, patients presenting with acute severe mitral regurgitation and considered too ill for immediate surgical intervention (EURO-II score &gt;11.2% plus pulmonary oedema necessitating mechanical ventilation and/or hemodynamic instability), were selected for an Impella-assisted LV unloading technique as bridge to MitraClip-procedure. Five patients were selected for the combined left Impella/MitraClip-procedure in two tertiary cardiac ICUs.

Results

The mean age was 72 years. The cause of MR was ischemic in 20% and all patients presented in cardiogenic shock state, necessitating mechanical ventilation. The overall cardiac operative risk assessment (Euro-II) score predicted a 35% chance of in-hospital mortality. Cardiac output was severely impaired (mean LVOT VTI 8.2 cm). All patients were on inotropic support and supported by an Impella-CP pVAD (mean flow 2.5 Liter per minute; mean 6.3 days of support). In all cases, we managed to reduce the LVEDP below 15 mmHg using the combination of medical therapy (afterload reduction, inotropes), mechanical ventilation and pVAD-therapy. The MR was significantly reduced by a MitraClip-procedure in each Impella supported patient. The overall survival at discharge was 80%. One patient with late referral and multiple organ failure at presentation deceased due to refractory cardiogenic shock. Overall, severe MR was reduced to grade 1+ and all four patients survived 6 months after discharge with only one readmission for decompensated heart failure.

Conclusions

A combined strategy of Impella and MitraClip appears to be a novel, feasible alternative for patients presenting with acute, severe MR unable to proceed to a corrective surgical procedure at presentation due to severe left ventricular forward flow failure. In these cases, the early initiation of pVAD-support may reduce the risk of development of irreversible end- organ damage and dysfunction. Exploration in a larger, randomised population is warranted to investigate this strategy further.

Funding Acknowledgement

Type of funding source: None

Clec4e signalling influences left-ventricular functional recovery in a murine model of myocardial ischemia-reperfusion injury

Introduction

The acute inflammatory response contributes substantially to functional recovery and remodelling of the left ventricle after acute ischemic injury. Previously, we have shown that the C-Type Lectin Receptor CLEC4E plays a role in early leukocyte recruitment during the acute inflammatory response of ischemia-reperfusion injury (I/R). However, the role of CLEC4E signalling in functional recovery of the left ventricle after I/R remains unknown. Therefore, we studied the chronic inflammatory response and left-ventricular remodelling in murine gene deletion model of Clec4e, subjected to I/R.

Methods

In anesthetized C57Bl6/J wild-type (n=14) and Clec4e−/− (n=13) mice, we transiently occluded the left-descending artery for 60 min, followed by 4 weeks reperfusion (I/R). A blood sample was collected at 90 minutes reperfusion to measure high-sensitivity troponin I (TnI) levels, as a surrogate marker of cardiac damage. At 4 weeks, mice underwent MRI (7T) to investigate the effect of Clec4e-gene deletion on LV-remodelling.

Results

Plasma TnI-levels showed no statistical difference between both groups, indicating that the initial insult was comparable. In wild-type mice, plasma TnI-levels negatively correlated with ejection fraction (EF, R2=0.92 p&lt;0.0001) at 4 weeks I/R, while Clec4e−/− mice showed preserved EF, irrespective of 90 minutes TnI-levels. MRI-analysis at 4 weeks after I/R showed significantly smaller end-diastolic and end-systolic volumes in Clec4e−/− mice, together with a trend towards a higher ejection fraction, suggesting better preserved structural and functional LV-remodelling (Fig.1).

Conclusion

The inflammatory leukocyte-associated Clec4e signalling pathway impairs functional recovery of the left ventricle after myocardial I/R injury. Inhibition of the Clec4e receptor may be a promising strategy in the treatment of ischemic injury.

Figure 1

Funding Acknowledgement

Type of funding source: Private grant(s) and/or Sponsorship. Main funding source(s): Scholarship Ir. Jozef en Mevr. Reinhilde De Swerts 2018-2022 by the Royal Academy of Medicine of Belgium

Nanoparticles loaded with hepatic growth factor and insulin-like growth factor-1 improve left ventricular repair in a porcine model of myocardial Ischemia reperfusion injury

Introduction

Nanomedicine offers great potential for treatment of cardiovascular disease. We tested whether intramyocardial (IM) injection of pro-angiogenic hepatocyte growth factor (HGF) and anti-apoptotic, pro-myogenic insulin-like growth factor 1 (IGF-1) encapsulated in Alginate-Sulfate nanoparticles (AlgS-NP) improves left ventricular (LV) functional recovery in a porcine ischemia-reperfusion (I/R) model.

Methods

Myocardial infarction (MI) was induced by 75min balloon occlusion of the mid-LAD followed by reperfusion. After 1w, pigs (n=12) with marked LV dysfunction (EF&lt;45%) were randomized to fusion imaging-guided IM injections of 8 mg Cy5-labelled AlgS-NP loaded with 200μg HGF and IGF-1 (GF) or with phosphate-buffered saline (CON) using the MYOSTAR injection catheter. AlgS-NP retention in the heart was determined by measuring Cy5 levels in peripheral blood. At 8w, treatment effect was evaluated using cardiac magnetic resonance imaging and coronary flow reserve (CFR) measurements, and further assessed using sirius red staining to measure myocardial fibrosis.

Results

At 1w after MI, LV ejection frqction (LVEF) was 37±5% (range 27–45%) and infarct size (IS)/LV mass 24±6% (range 19–38%). Myocardial retention of AlgS-NP was comparable between 2 groups (maximal systemic leakage after IM injection: 9% CON vs 20% GF, P=0.25). After 8 w, IS/LV mass decreased by one third in GF-treated pigs compared with 14% in CON (P=0.03, Fig. A) and was associated with a trend towards improvement in CFR (P=0.05, Fig. B). LVEF significantly increased in GF-treated pigs (6±2% vs. −1±1%, P=0.02, Fig. C), which was attributable to a greater reduction in end-systolic volume. The improvement in LVEF was also consistent with significant reduction of fibrosis (P=0.01, Fig. D) in the peri-infarct zone (PI).

Conclusions

Intramyocardial injection of AlgS-nanoparticle-encapsulated HGF and IGF-1 to the ischemic myocardium significantly improves LV repair, and offers the prospect of innovative treatment for patients with refractory ischemic heart disease.

Funding Acknowledgement

Type of funding source: Public grant(s) – EU funding. Main funding source(s): EuroNanoMed, Horizon 2020

Acquired von Willebrand Syndrome in left Impella supported cardiogenic shock patients

Background

Bleeding is a main cause of morbidity and mortality in critically ill cardiogenic shock patients, supported by short-term percutaneous mechanical circulatory support (pMCS) devices. Bleeding not only occurs because of obligatory heparin and antiplatelet therapy (both required in the prevention of pump and stent thrombosis) but possibly also results from device-related coagulopathy. Similar to long-term ventricular assist devices, mechanical shear-induced acquired von Willebrand syndrome (AVWS) might further increase the bleeding risk. Therefore, we aimed to investigate the effect of left Impella percutaneous continuous flow pumps on the development of AVWS due to shear-induced excessive cleavage of large vWF multimers by the metalloproteinase ADAMTS-13, resulting in loss of high-molecular-weight vWF multimers.

Methods

Between March 2019 and January 2020, all cardiogenic shock patients supported by a left Impella and referred to a single tertiary ICU were studied. Both vWF Antigen (vWF:Ag) and vWF:GPIbR (ristocetin-induced binding of vWF to a recombinant wildtype Glycoprotein Ib fragment) levels were measured by chemiluminescent immunoassays using an AcuStar (Werfen) assay to determine the vWF:GPIbR /vWF:Ag ratio (normal range ≥1.0). VWF multimer analysis was performed by electrophoresis. On-pump analyses were performed 12h after implantation and off-pump analyses 12h after Impella explantation. Patients who died on-pump were excluded because of lack of paired data after explantation.

Results

Eight left Impella patients (four Impella CP, four Impella 5.0) were analyzed for AVWS. The vWF:GPIbR /vWF:Ag ratio was &lt;1.0 in all patients on-pump (mean±SD 0.68±0.1 versus 1.1±0.15 off-pump (panel A; p=0.0018)) and thus AVWS was detected in all Impella-supported patients. The presence of AVSW was also confirmed by loss of large vWF multimers on-pump (panel B). Four patients (50%) had mucosal bleeds (epistaxis or gastrointestinal), none of them requiring transfusion. The mean rise in ratio 12h after pump removal was 0.35 which was also reflected by recovery of large multimers by electrophoresis (panel B).

Conclusions

Our data highlight the rapid onset and reversal of AVWS in all studied cardiogenic shock patients, supported by a left Impella pump. The determination of the GPIbR /vWF:Ag ratio with the AcuStar appears a reliable and faster test to detect AVWS as compared to vWF multimers electrophoresis. Further research into innovative pharmacological interventions (e.g. ADAMTS-13 inhibitors) should target pMCS-induced AVWS in an effort to reduce hemostatic complications in this critically ill ICU population.

AVWS in Impella supported patients

Funding Acknowledgement

Type of funding source: None

Estimation of left ventricular filling pressures in transplanted hearts by echocardiography – do current guidelines work?

Introduction

End-stage heart failure (HF) can be successfully treated with heart transplantation (HTx), which reduces mortality and improves quality of life (QoL). Diastolic dysfunction and subsequently increased left ventricular (LV) filling pressures can be an early sign of rejection, while later after HTx, they can be suggestive for other insults to the myocardium, for example related to transplant vasculopathy. Therefore, right heart catheterization (RHC) remains a standard follow-up examination in patients after HTx. It has been questioned, whether echocardiography can accurately predict the LV filling pressures in HTx patients, and whether echocardiographic diastolic parameters correlate with hemodynamics in this population. Therefore, our study aimed to investigate the correlation between invasive measurements and echocardiographic estimates of LV filling pressures in HTx patients.

Methods

We analyzed 461 consecutive HTx patients who underwent RHC and transthoracic echocardiography on the same day. Patients were classified as having elevated LV filling pressures when the pulmonary capillary wedge (PCWP) was ≥15 mmHg. Standard echocardiographic parameters of systolic and diastolic function were measured and the decision tree of the recommendations on diastolic dysfunction assessment of the American and European imaging societies (ASE/EACVI) was applied to detect elevated LV filling pressures and determine the diastolic dysfunction grade.

Results

The invasive measurements showed elevated LV filling pressures in 303 (66%) of HTx patients. Based on the echocardiographic parameters, HTx patients were classified into the following groups: normal diastolic function (n=151, 33%), grade I (n=87, 19%), grade II (n=21,5%), and grade III (n=151, 33%) diastolic dysfunction, and indetermined group (n=51, 11%). The PCWP values differed between the groups: 14.4±0.3 mmHg vs. 13.3±0.4 vs. 20.5±0.9 mmHg vs. 22.2±0.3 mmHg vs. 17.7±0.6 mmHg, p=0.0001, accordingly (Figure A). The PCWP showed moderate correlation with E/A (r=0.49, p=0.0001) and E/e' (r=0.40, p=0.0001) (Figures B and C, resp.). The decision tree of the ASE/EACVI recommendations predicted elevated LV filling pressures with a sensitivity of 64%, specificity of 98%, negative predictive value of 59% and positive predictive value (PPV) of 98%.

Conclusions

Our study is the first to demonstrate a correlation between the LV filling pressures estimated from echocardiography and invasively measured during RHC in large HTx population. Echocardiography alone can reliably describe elevated LV filling pressures with a high PPV. The sensitivity of the algorithm, however, is limited. Additional parameters need to be identified to increase the sensitivity of the current recommendations for detection of elevated filling pressures this patients population.

Figure 1

Funding Acknowledgement

Type of funding source: None

TAOK3 is a MAP3K contributing to osteoblast differentiation and skeletal mineralization

Current anabolic drugs to treat osteoporosis and other disorders of low bone mass all have important limitations in terms of toxicity, contraindications, or poor efficacy in certain contexts. Addressing these limitations will require a better understanding of the molecular pathways, such as the mitogen activated protein kinase (MAPK) pathways, that govern osteoblast differentiation and, thereby, skeletal mineralization. Whereas MAP3Ks functioning in the extracellular signal-regulated kinases (ERK) and p38 pathways have been identified in osteoblasts, MAP3Ks mediating proximal activation of the c-Jun N-terminal kinase (JNK) pathway have yet to be identified. Here, we demonstrate that thousand-and-one kinase 3 (TAOK3, MAP3K18) functions as an upstream activator of the JNK pathway in osteoblasts both in vitro and in vivo. Taok3-deficient osteoblasts displayed defective JNK pathway activation and a marked decrease in osteoblast differentiation markers and defective mineralization, which was also confirmed using TAOK3 deficient osteoblasts derived from human MSCs. Additionally, reduced expression of Taok3 in a murine model resulted in osteopenia that phenocopies aspects of the Jnk1-associated skeletal phenotype such as occipital hypomineralization. Thus, in vitro and in vivo evidence supports TAOK3 as a proximal activator of the JNK pathway in osteoblasts that plays a critical role in skeletal mineralization.

ER stress in antigen-presenting cells promotes NKT cell activation through endogenous neutral lipids

CD1d‐restricted invariant natural killer T (iNKT) cells constitute a common glycolipid‐reactive innate‐like T‐cell subset with a broad impact on innate and adaptive immunity. While several microbial glycolipids are known to activate iNKT cells, the cellular mechanisms leading to endogenous CD1d‐dependent glycolipid responses remain largely unclear. Here, we show that endoplasmic reticulum (ER) stress in APCs is a potent inducer of CD1d‐dependent iNKT cell autoreactivity. This pathway relies on the presence of two transducers of the unfolded protein response: inositol‐requiring enzyme‐1a (IRE1α) and protein kinase R‐like ER kinase (PERK). Surprisingly, the neutral but not the polar lipids generated within APCs undergoing ER stress are capable of activating iNKT cells. These data reveal that ER stress is an important mechanism to elicit endogenous CD1d‐restricted iNKT cell responses through induction of distinct classes of neutral lipids.