Usability and feasibility of E-nergEYEze: a blended vision-specific E-health based cognitive behavioral therapy and self-management intervention to reduce fatigue in adults with visual impairment

BACKGROUND

Over 50% of adults with visual impairment experience severe fatigue. Therefore, we developed a guided E-health intervention based on cognitive behavioral therapy and self-management to reduce fatigue in this population. This pilot study evaluated the usability, feasibility, fidelity and potential effectiveness of E-nergEYEze.

METHODS

E-nergEYEze was developed by a design team and customized by conducting a pilot study using an iterative development strategy. The intervention was first tested in a usability study among adults with visual impairment (n = 5). Participants were asked to think-aloud while exploring the intervention features and a semi-structured interview was performed afterwards. Subsequently, the enhanced intervention was tested in a feasibility study. Adults with visual impairment and severe fatigue (n = 10) followed the intervention partially with guidance from a social worker and one-time computer trainer support. Fatigue severity (Checklist Individual Strength), fatigue impact (Modified Fatigue Impact Scale) and cognitive behavioral therapy skills (Competencies of Cognitive Therapy Scale-Self Report) were measured at baseline and at three months follow-up and analyzed with the Wilcoxon signed-rank test. The intervention was evaluated through evaluation forms.

RESULTS

The usability study resulted in adjustments to content and lay-out with regard to optically shortened text sentences, separate pages for information and assignments with one read-aloud audio and an additional descriptive explanation of page content. Digital challenges were overcome with mandatory computer training and e-platform modifications. The feasibility study showed a positive trend in reducing fatigue severity (Z -6.108; P < .001; SD 8.4), impact of fatigue (Z - 4.451; P < .001; SD 11.4) and cognitive behavioral therapy skills (Z -2.278; P = .023; SD 19.3). Participants gave useful feedback regarding accessibility, content and guidance, with an overall positive experience. The intervention was rated with a median score of 8 (range 7-10).

CONCLUSION

We developed, evaluated and optimized E-nergEYEze by applying a user-centered and iterative approach. E-nergEYEze showed a promising trend to reduce fatigue severity and impact of fatigue and to increase cognitive behavioral therapy skills. The study methods were feasible and the fidelity of the intervention protocol was suitable. Performing a randomized controlled trial is warranted to give insight into whether E-nergEYEze is cost-effective in reducing severe fatigue in adults with visual impairment.

TRIAL REGISTRATION

International Clinical Trial Registry Platform: NL7764. Date registered: 28-05-2019.

Preliminary Study on Open Labelled Randomized Controlled Trial of the Safety and Efficacy of Hydroxychloroquine and Chloroquine Phosphate for the Treatment of Persons Infected with 2019 Coronavirus Disease in Nigeria

BACKGROUND

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a causative agent of COVID-19 is a leading cause of ill-health and deaths worldwide. Currently, COVID-19 has no known widely approved therapeutics. Thus, the need for effective treatment.

OBJECTIVES

We investigated the safety and efficacy of two (2) therapeutic agents; chloroquine phosphate (CQ), 2- hydroxychloroquine (HCQ) and a control (standard supportive therapy) among hospitalized adults with COVID-19.

METHODS

The clinical trial was done in accordance to the World Health Organization master protocol for investigational therapeutics for COVID-19. Atotal of 40 participants with laboratory-confirmed positive COVID-19 were enrolled. Blood samples and oropharyngeal (OP) swabs were obtained on days 1,3,15 and 29 for safety and efficacy assessments.

RESULTS

The baseline demographics showed that the median ages in years (range) were 45 (31-57) in CQ, 45 (36.5-60.5) in HCQ, 43 (39.5-67.0) and 44.5 (25.3-51.3) in the control (P<0.042).At randomization, seven (7) participants were asymptomatic, thirty-three (33) had mild symptoms, eight (8) had moderate symptoms while three (3) had severe symptoms. The average day of conversion to negative COVID-19 was 15.5 days for CQ, 16 days for HCQ and 18 days for the control(P=0.036).

CONCLUSION

The safety assessment revealed no adverse effect of the drugs in COVID-19 patients after treatment. These findings proved that chloroquine and hydroxychloroquine are effective for the treatment of COVID-19 among hospitalized adults. It also confirmed that they are safe.

The effectiveness of motivational interviewing on adherence to wearing orthopedic shoes in people with diabetes at low-to-high risk of foot ulceration: A multicenter cluster-randomized controlled trial

AIM

To evaluate the effectiveness of motivational interviewing (MI) performed by MI-trained podiatrists in improving adherence to wearing orthopedic shoes in comparison to usual care in people with diabetes at low-to-high risk of ulceration.

METHODS

People with diabetes with loss of protective sensation and/or peripheral artery disease, and with orthopedic shoes prescription were allocated to receive one MI-consultation by a podiatrist randomized to MI training (n = 53) or usual care only (n = 68). Adherence was measured as the percentage of steps taken while wearing orthopedic shoes, determined using an insole temperature microsensor and wrist-worn activity tracker during one week at 3 and 6 months.

RESULTS

The proportion of participants ≥80 % adherent to wearing their orthopedic shoes was higher in the control group than in the MI-intervention group at 3 months (30.9 % versus 15.1 %; p = 0.044), and not significantly different at 6 months (22.1 % versus 13.2 %; p = 0.210). Average adherence was also higher in the control group than the intervention group at both 3 months (60.9 % versus 50.9 %; p = 0.029) and 6 months (59.9 % versus 49.5 %; p = 0.025).

CONCLUSIONS

One podiatrist-led MI-consultation in its current form did not result in higher adherence to wearing orthopedic shoes in people with diabetes 3 and 6 months after inclusion.

TRIAL REGISTRATION

Netherlands Trial Register NL7710 (available on the International Clinical Trials Registry Platform).

NLRP3 mediates atheromatous plaque macrophage proliferation

Background

Macrophage accumulation in atherosclerotic plaques drives disease progression largely dependent on in situ proliferation. We previously reported that systemic cholesterol lowering or reduced modified lipoprotein uptake supress atheromatous plaque macrophage proliferation. In this work we investigate the intracellular mediators of macrophage proliferation.

Methods and results

Macrophages deficient in scavenger receptors CD36 or Msr1 and impaired in cholesterol-rich lipoprotein uptake, proliferated less compared to control macrophages in the same plaque exposed to the same lipid levels in a LDLR-deficient bone marrow irradiation mixed chimera model. Proliferation of plaque macrophages deficient in the intracellular cholesterol sensor LXR was not impaired, however. As modified LDL uptake can activate the NLRP3 inflammasome, we generated mixed bone marrow knockout chimeras for components of the inflammasome. NLRP3 but not Caspase-1 or interleukin-1 receptor deficient macrophages proliferated 35% less compared to NLRP3-expressing macrophages in the same plaque in vivo. These results were confirmed in NLRP3-deficient oxLDL stimulated macrophages in vitro. In line, NLRP3 inhibition of human carotid artery plaque cultures suppressed human plaque macrophage proliferation and reduced inflammasome-dependent IL-1b secretion. However, IL-1b supplementation did not restore local macrophage proliferation in accord with our findings in IL-1 receptor deficient murine plaque macrophages.

Conclusion

We identified a novel role for NLRP3, independent of the canonical Caspase-1–IL-1b inflammasome pathway, in mediating macrophage proliferation in atherosclerotic plaques in mice and men representing a druggable target.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): DFG

Analysis of surgical bailout after transcatheter aortic valve replacement in Germany

Background

Severe complications during transcatheter aortic valve replacement (TAVR) may require a surgical bailout. However, little is known about the outcomes after bailout in Germany.

Methods

All TAVR between 2007 and 2020 were identified using German national electronic health records, with focus on 2018 to 2020. Additionally, those procedures requiring surgical bailout were selected.

Results

A total of 159,643 patients received TAVR. Overall rate of surgical bailout was 2.30% and overall in-hospital mortality 3.85%. In-hospital mortality after surgical bailout was 16.51%. While the annual number of procedures in all TAVR rose steeply (202 to 22,972), the rate of surgical bailout dropped from 27.23 to 0.61% and that of overall mortality from 11.39 to 2.29%. However, mortality in case of surgical bailout remained high with 28.37% in 2020. After risk adjustment, in 2018 to 2020, standardized rates of overall in-hospital mortality and surgical bailout for both balloon-expandable and self-expanding transfemoral TAVR were significantly lower than for transapical TAVR (transapical vs transfemoral balloon-expandable vs self-expanding TAVR: in-hospital mortality: 5.66% [95% CI 4.81%; 6.52%] vs 2.30% [2.03%; 2.57%] vs 2.32% [2.07%; 2.57%]; surgical bailout: 2.33% [1.68%; 2.97%] vs 0.79% [0.60%; 0.98%] vs 0.42% [0.31%; 0.53%]). Main risk factors for surgical bailout were coronary artery disease (risk adjusted OR=1.50 [1.21; 1.85], p&lt;0.001), atrial fibrillation (OR=1.29 [1.07; 1.57], p=0.009), and higher grade heart failure NYHA III/IV (OR=1.26 [1.01; 1.57], p=0.037).

Conclusion

Rates of surgical bailout as well as overall in-hospital mortality after TAVR decrease substantially over the years. However, in the case of surgical bailout, outcomes remain poor with a constantly high in-hospital mortality.

Funding Acknowledgement

Type of funding sources: None.

Evaluation of symptomatic peripheral artery disease with media sclerosis using shear wave elastography of the lower limb muscle

Background

Symptomatic peripheral artery disease (PAD) is challenging to diagnose in the presence of media sclerosis with incompressible arteries since standard ankle-brachial index (ABI) cannot be applied. Shear wave elastography (SWE) provides a novel ultrasound technique to measure muscle stiffness and to visualize muscle deficits at rest and during contraction. Furthermore, reduced muscle stiffness correlates with a possible hypoperfusion in the affected area. It is fast, non-invasive and associated with peripheral muscle weakness in chronic heart failure patients.

Purpose

SWE presents an important diagnostic tool for patients with PAD and concomitant media sclerosis. In this prospective observation study we evaluated the alterations of muscle stiffness (measured in kPa) at rest and during controlled activity.

Methods

Fifteen patients with peripheral artery disease and media sclerosis were included in this pilot study. Thirteen patients were symptomatic in different stages of PAD as a result of significant arterial stenosis/occlusions of the lower legs as assessed by oscillography and duplex sonography. ABI was invalid due to media sclerosis in all 15 patients. The examination was performed at rest and during contraction depicted by active dorsal flexion of the foot on both sides. The medial gastrocnemius muscle was used as a region of interest.

Results

Mean SWE measurements of medial gastrocnemius muscles showed significant muscle weakness at maximum exercise (103.4±25.9 kPa on the asymptomatic vs. 62.5±21.9 kPa in the symptomatic lower leg (p&lt;0.001). Oscillography confirmed the SWE results by a decreased signal on the clinically symptomatic side.

Conclusion

SWE is suitable to detect muscle weakness during exercise in the symptomatic leg of mediasclerotic PAD patients. Since ABI measurements are usually invalid these patients with media sclerosis, shear wave elastography of lower limb muscles may contribute for a non-invasive diagnosis of symptomatic PAD. Larger randomized clinical trials are necessary to confirm our results.

Funding Acknowledgement

Type of funding sources: None.

Robotic-assisted PCI – insights from a monocenter registry

Background

Robotics in interventional cardiology is a rapidly evolving technique, which is still in an early phase of development and clinical application. Beside the pivotal studies, there is limited real world data on success rates and safety of this new technology.

Purpose

To investigate the success rate as well as the safety profile of robotic-assisted percutaneous coronary intervention (R-PCI) and compare it with manual PCI (M-PCI).

Methods

We report preliminary data of our ongoing, prospective FRiK registry, started in mid 2021. This registry focuses on success rates and safety, radiation dose of patients and personnel, long-term outcome (after 6, 12 and 24 months), as well as on economic aspects and the learning curve of the interventionalists. Moreover, the R-PCI is compared with the M-PCI in these categories.

Results

So far, 51 patients (age 69 (62–80) years, BMI 28.4 (25.2–32) kg/m2, 74.5% male), received R-PCI. PCI success rate was 100%, with 15% requiring manual assistance (Figure 1). Rate of complications (myocardial infarction after PCI, dissection, stent thrombosis, pericardial effusion, target lesion revascularization and MACE (major adverse cardiovascular events) was 0%.

Compared with 41 M-PCI patients (Table 1), treated by the same interventionalists, there was a higher median procedural time (diagnostic and intervention) 106 (82–127) min vs. 71 (54–93) min (p&lt;0.001) and fluoroscopy time 20.3 (14.8–28.5) min vs. 14.8 (10.4–22.4) min (p=0.012) in R-PCI patients. However, there was no significant difference between the dose-area product 4662.4 (3019.4–6399.2) cGy cm2 vs. 4193.9 (2759.9–6254.3) cGy cm2 (p=0.487) and contrast volume use 200 (150–280) ml vs. 180 (145–255) ml (p=0.587).

Conclusion

Preliminary results of R-PCI showed a high success rate, low rates for need of manual assistance, and a very high safety profile without any complications. The dose-area product and contrast volume use were comparable between R-PCI and M-PCI, whereas R-PCI showed a longer procedural and fluoroscopy time. Future steps will include a larger number of cases and definitions of patient cases with optimal eligibility for R-PCI.

Funding Acknowledgement

Type of funding sources: None.

Volume-outcome relationship in emergency transcatheter aortic valve implantations in Germany

Background

An inverse volume-outcome relationship in transcatheter aortic valve implantation (TAVI) has been demonstrated in the literature but little is known about emergency cases.

Methods

All isolated balloon-expandable and self-expanding transfemoral TAVI in 2018 were identified using German national electronic health records. Additionally, those patients with an emergency admission were selected.

Results

A total of 17,295 patients received TAVI, 1,682 of these cases had an emergency admission. Of the emergency cases, 49.2% were female, mean age was 81.2 years and logistic EuroSCORE was 23.3%. Relatively more emergency cases were treated in lower volume centers than in higher volume centers (p&lt;0.001): Centers performing &lt;50 TAVI had an emergency admission rate of ∼15% while centers performing &gt;200 TAVI were associated with a rate of ∼11%. Analyzing the outcomes for a volume increase per 10 emergency cases using propensity score adjustment, higher volume centers showed significantly better results than lower volume centers for in-hospital mortality (OR=0.872, p=0.043), major bleeding (OR=0.772, p=0.001), stroke (OR=0.816, p=0.044), mechanical ventilation &gt;48h (OR=0.749, p=0.001), length of hospital stay (risk adjusted difference in days of hospitalization per 10 emergency admissions: −1.01 days, p&lt;0.001), and reimbursement (risk adjusted difference in reimbursement per 10 emergency admissions: −€314.89, p&lt;0.001). No correlation was seen in acute kidney injury (OR=0.951, p=0.104), postoperative delirium (OR=0.975, p=0.480), and permanent pacemaker implantation (OR=1.010, p=0.732).

Conclusion

In transfemoral TAVI, lower volume centers treat relatively more emergency cases in Germany, but higher volume centers provide significantly better outcomes regarding in-hospital mortality and complication rates as well as resource utilization parameters.

Funding Acknowledgement

Type of funding sources: None.

COVID-19 pandemic affects STEMI numbers and in-hospital mortality: results of a nationwide analysis in Germany

Background

The COVID-19 pandemic led to extensive restrictions in Germany in 2020, including the postponement of elective interventions. We examined the impact on ST-elevation myocardial infarction (STEMI) as an acute and non-postponable disease.

Methods

Using German national records, all STEMI between 2017 and 2020 were identified. Using the number of STEMI cases between 2017 and 2019, we created a forecast for 2020 using poisson regression models and compared it with the observed number of STEMI in 2020.

Results

From 2017 to 2020, 248,062 patients were treated for a STEMI in Germany. Mean age was 65.21 years and 28.36% were female. When comparing forecasted and observed STEMI in 2020, a correlation can be seen: Noticeably fewer STEMI were treated in those weeks respectively months with an increasing COVID-19 hospitalization rate (monthly percentage decrease in STEMI: March −14.85% April −13.39%, November −11.92%, December −22.95%). At the same time, the risk-adjusted in-hospital mortality increased significantly at the peaks of the first and second waves (monthly in-hospital mortality: April RR=1.11 [95% CI 1.02; 1.21], November 1.13 [1.04; 1.24], December 1.16 [1.06; 1.27]).

Conclusion

The COVID-19 pandemic led to a noticeable decrease in the number of STEMI interventions in Germany at the peaks of the first and second waves in 2020, corresponding to an increase in COVID-19 hospitalizations. At the same time, in-hospital mortality after STEMI increased significantly in these phases.

Funding Acknowledgement

Type of funding sources: None.

The role of P2Y12 in cardiovascular disease beyond atherothrombosis: P2Y12 signaling promotes emergency hematopoiesis after myocardial infarction

Background

Adenosine diphosphate (ADP) plays a pivotal role in platelet activation. The purinergic ADP-receptor P2Y12 has therefore been targeted in the treatment of cardiovascular disease (CVD) to prevent atherothrombosis (1). Beyond P2Y12 expression on platelets, purinergic receptors have also been described on hematopoietic stem and progenitor cells (LSK) (2). After myocardial infarction (MI), accelerated LSK proliferation launches emergency hematopoiesis as the driving force behind the inflammatory response to MI, increasing inflammatory cell production in the bone marrow (BM) and providing leukocyte resupply for local cell recruitment to the infarct (3). The inflammatory cascade after MI covers intricate multilayered interactions between the injured myocardium and the hematopoietic BM that still remain to be fully elucidated and may unearth novel therapeutic strategies. Whereas P2X receptors have recently been found to be involved in cell trafficking (4), the role of P2Y receptors in the hematopoietic BM have not yet been characterized.

Purpose

This study aims to characterize the influence of P2Y12 signaling on emergency hematopoiesis and cardiac remodeling after MI.

Methods

Permanent coronary ligation was performed for MI to assess BM activation, inflammatory cell composition, cardiac remodeling and function in murine global and platelet-specific P2Y12 knockout models and under pharmacological P2Y12 inhibition with prasugrel using flow cytometry, qPCR, immunohistochemistry and echocardiography. In vitro studies including colony forming unit (CFU) assays and flow cytometry allowed for investigation of ADP-dependent effects on LSK cells and intracellular pathway analysis.

Results

We identified ADP as a danger signal for the hematopoietic BM, fueling emergency hematopoiesis by promoting Akt phosphorylation and cell cycle progression. Detection of P2Y12 expression in LSK implicated a direct effect of ADP on LSK via P2Y12 signaling. P2Y12 deficiency and P2Y12 inhibition with prasugrel decelerated emergency hematopoiesis and consecutively reduced the excessive inflammatory response to MI, translating to lower numbers of hematopoietic progenitors and inflammatory cells in the blood and infarct. Ultimately, P2Y12 inhibition ameliorated chronic adverse cardiac remodeling and preserved cardiac function after MI.

Conclusion

ADP-dependent P2Y12-mediated activation of hematopoietic stem and progenitor cells in the BM promotes emergency hematopoiesis after MI and fuels post-ischemic inflammation, proposing a novel role of P2Y12 antagonists in CVD beyond atherothrombosis.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Deutsche Forschungsgemeinschaft (DFG)

Association of coagulation markers and antiphospholipid antibodies with ischemic and bleeding risk in patients with atrial fibrillation undergoing percutaneous coronary intervention

Background

Antiphospholipid antibodies and other coagulation markers are associated with ischemic risk in patients with coronary artery disease without oral anticoagulation (OAC).

Aim

To assess the association of antiphospholipid antibodies (aPL) and conventional markers of coagulation with ischemic and bleeding risk in patients with atrial fibrillation (AF) undergoing percutaneous coronary intervention (PCI).

Patients and methods

In this prospective single center observational cohort study, patients with AF and an indication for OAC were enrolled after PCI. Dilute Russell's viper venom time (DRVVT) was used to determine lupus anticoagulants (LA) in direct OAC-free plasma. Anti-cardiolipin IgG (aCL), IgM and anti-beta2GP-1-IgG (aβ2GP1) were analyzed by enzyme linked immunosorbent assay (ELISA). Fibrinogen C (FIBC), d-dimers and prothrombin fragments 1 and 2 (PF1+2) were measured in citrated plasma. Immature platelet fraction (IPF [%]) and absolute (IPF abs. [103/μl]) were measured in EDTA-blood. The primary ischemic outcome was defined as time to major adverse cardiovascular events (MACE: all-cause death, myocardial infarction, or stroke) assessed at 6 months. Bleeding was defined according to the International Society of Thrombosis and Haemostasis (ISTH) and the Bleeding Academic Research Consortium (BARC).

Results

158 patients were enrolled between May 2020 and May 2021. The median age was 78 years (interquartile range, IQR 72–82), 111 (70%) were male, and 39 (25%) presented with acute coronary syndrome. All Patients were treated with clopidogrel and OAC, 145 (92%) in addition with acetylsalicylic acid (ASA). 32 patients (20%) had ≥1 antiphospholipid antibody (aPL; LA: 19 [12%], aCL: 14 [9%], aβ2GP1: 2 [1%]). D-dimers were elevated in 74 patients (47%), FIBC was increased in 40 (25%) and PF1+2 in 68 patients (43%). IPF [%] was elevated in 28 (18%) and IPF abs. [103/μl] in 11 (7%). The presence of aPL was neither significantly associated with MACE, nor with bleeding risk. Elevated d-dimers were significantly associated with higher risk for MACE (HR=5.1, 95% CI [1.1; 23.4], p=0.04), major ISTH bleeding events (HR= 6.9, 95% CI [1.5; 30.8], p=0.01) and BARC bleeding type 3 or 5 (HR=6.4, 95% CI [1.4; 28.7], p=0.02). Increased levels of FIBC were associated with risk of MACE (HR= 3.6, 95% CI [1.1; 12.0], p=0.03 (Table 1).

Conclusion

In patients with AF undergoing PCI, high levels of d-dimers and fibrinogen C indicate an increased ischemic risk. Elevated d-dimers are associated with higher risk for bleeding. aPL positivity was not significantly associated with outcome possibly due to low sample size. A combined panel of biomarkers might be suitable to assess ischemic and bleeding risk in patients with AF following PCI.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): Faculty of Medicine, Freiburg

Attitudes and experiences towards the application of motivational interviewing by podiatrists working with people with diabetes at high-risk of developing foot ulcers: a mixed-methods study

Background

Podiatrists are key professionals in promoting adequate foot self-care for people with diabetes at high-risk of developing foot ulcers. However, merely informing patients about the advantages of foot self-care is insufficient to realise behavioural change. Motivational interviewing (MI) is a promising person-centred communication style that could help to create a working alliance between healthcare providers and patient to improve foot self-care. This study aims to observe and analyse the application of MI in consultations carried out by MI-trained and non-MI-trained podiatrists with their patients, and explore podiatrists’ attitudes and experiences towards MI.

Methods

Eighteen podiatrists (median age: 28.5 years, 10 female and 8 male) followed a three-day basic training in MI and 4 podiatrists (median age: 38.5 years, 4 female) were not trained in MI. To observe and rate the MI-fidelity in daily clinical practice, audio recordings from the MI-trained and non-MI-trained podiatrists were scored with the Motivational Interviewing Treatment Integrity code. Individual, semi-structed, in-depth interviews were conducted with the MI-trained podiatrists to explore their attitudes towards and experiences with MI. These data sources were triangulated to describe the effect of training podiatrists in MI for their clinical practice.

Results

The MI-trained podiatrists scored significantly higher than the non-MI-trained podiatrists on two of four global MI-related communication skills (empathy, p = 0.008 and change talk, p = 0.008), on one of five core MI-adherent behaviours (affirmation, p = 0.041) and on one of the other behaviour counts (simple reflections, p = 0.008). The podiatrists mainly reported their attitudes and experiences regarding partnership and cultivating change talk, during the interviews. In addition, they also mentioned facilitators and barriers to using MI and indicated whether they experienced MI as having added value.

Conclusions

The MI-trained podiatrists used the principles of MI at a solid beginner proficiency level in their clinical practice in comparison to the non-MI-trained podiatrists, who did not reach this level. This achievement is in accordance with the basic MI-training they received. This multi-method study reveals that podiatrists can be effectively trained in applying MI in daily clinical practice.

Trial registration

Netherlands Trial Register NL7710. Registered: 6 May 2019.

Using motivational interviewing combined with digital shoe-fitting to improve adherence to wearing orthopedic shoes in people with diabetes at risk of foot ulceration: study protocol for a cluster-randomized controlled trial

Background

Diabetic foot ulcers have a high impact on mobility and daily functioning and lead to high treatment costs, for example, by hospitalization and amputation. To prevent (re)ulcerations, custom-made orthopedic shoes are considered essential. However, adherence to wearing the orthopedic shoes is low, and improving adherence was not successful in the past. We propose a novel care approach that combines motivational interviewing (MI) with a digital shoe-fitting procedure to improve adherence to orthopedic shoes. The aim of this trial is to assess the (cost-)effectiveness of this novel care approach compared to usual care (no MI and casting-based shoe-fitting) in promoting footwear adherence and ulcer prevention.

Methods

The trial will include people with diabetes, with IWGDF Risk categories 1–3, who have been prescribed orthopedic shoes. Participants will be randomized at the level of the podiatrist to the novel care approach or usual care. The primary outcome is the proportion of participants who adhere to the use of their orthopedic shoes, that is, who take at least 80% of their total daily steps with orthopedic shoes. A temperature microsensor will be built into the participants’ orthopedic shoes to measure wearing time continuously over 12 months. In addition, daily activity will be measured periodically using log data with an activity monitor. Data from the temperature microsensor and activity monitor will be combined to calculate adherence. (Re-)experienced complications after receiving orthopedic shoes will be registered. Questionnaires and interviews will measure the experiences of participants regarding orthopedic shoes, experiences of podiatrists regarding motivational interviewing, care consumption, and quality of life. Differences in costs and quality of life will be determined in a cost-effectiveness analysis.

Discussion

This trial will generate novel insights into the socio-economic and well-being impact and the clinical effectiveness of the novel care approach on adherence to wearing orthopedic shoes.

Trial registration

Netherlands Trial Register NL7710. Registered on 6 May 2019

Impact of pulse pressure on clinical outcome in extracorporeal cardiopulmonary resuscitation (eCPR) patients

Background

Hemodynamic response after successful extracorporeal cardiopulmonary resuscitation (eCPR) is very heterogeneous. Pulse pressure (PP) as an easy to access surrogate parameter and correlate for myocardial damage or recovery from it, might be a valuable tool to estimate the outcome of these patients.

Purpose

To investigate the predictive value of the surrogate parameter PP in eCPR patients.

Methods

We report retrospective data of a single-centre registry of eCPR patients, treated at our Interdisciplinary Medical Intensive Care Unit between 01/2017 and 01/2020. The association between PP of the first 10 days after eCPR and hospital survival was investigated. Moreover, patients were divided into three groups according to their PP (low (0–9 mmHg), mid (10–29 mmHg) and high (≥30 mmHg)) at each time point.

Results

143 patients (age 63 years, 74.1% male, 40% OHCA, average low flow time 49 min) were analysed. Overall hospital survival rate was 28%. A low PP both early after eCPR (after 1, 3, 6 and 12 hours) and in the further course after day 1 to day 8 was associated with reduced hospital survival. At each time point (1 hour to day 5) the classification of patients into a low, mid and high PP group was able to categorize the patients for a low (5–20%), moderate (20–40%) and high (50–70%) survival rate. A multivariable analysis showed that the mean PP of the first 24 hours was an independent predictor for survival (p=0.008, figure 1).

Conclusion

In this analysis, PP occurred to be a valuable parameter to estimate survival and maybe support clinical decision making in the further course of patients after eCPR.

Funding Acknowledgement

Type of funding sources: None. Figure 1. Survival of eCPR patients by mean 24hPP

Self-expanding and balloon-expandable transfemoral transcatheter aortic valve replacement: in-hospital outcomes in Germany

Background

The impact of valve type used in transfemoral transcatheter aortic valve replacement (TF-TAVR) on outcomes is currently under discussion.

Purpose

We examine the in-hospital outcomes of balloon-expandable (BE) and self-expanding (SE) valves in a complete national cohort in Germany in 2018.

Methods

All 17,295 patients receiving TF-TAVR with BE (N=9,882) or SE (N=7,413) valves in Germany in 2018 were identified. Outcomes were analyzed for the endpoints in-hospital mortality, major bleeding, stroke, acute kidney injury, postoperative delirium, mechanical ventilation &gt;48h, length of hospital stay, and reimbursement. Since there was no randomization of patients to the two treatment options, logistic or linear regression models were carried out using 22 baseline patient characteristics and center-specific variables as potential confounders. Propensity score methods served as sensitivity analysis.

Results

Both valve types differed significantly in baseline characteristics with higher EuroSCORE (p&lt;0.001), age (p&lt;0.001) and rate of female sex (p&lt;0.001) in patients treated with SE valves. After risk adjustment, there were no marked differences in outcomes for in-hospital mortality (risk adjusted odds ratio (aOR) for SE instead of BE: 0.94 [95% CI 0.76; 1.17], p=0.617), major bleeding (aOR 0.91 [0.73; 1.14], p=0.400), stroke (aOR 1.13 [0.88; 1.46], p=0.347), acute kidney injury (aOR 0.97 [0.85; 1.10], p=0.621), postoperative delirium (aOR 1.09 [0.96; 1.24], p=0.184), mechanical ventilation &gt;48h (aOR 0.98 [0.77; 1.25], p=0.893), length of hospital stay (risk adjusted difference in days of hospitalization: −0.05 [−0.34; 0.25], p=0.762) and reimbursement (−€72 [−€291; €147], p=0.519). Similar results were found using propensity score methods.

Conclusion

Outcomes in contemporary TF-TAVR procedures are broadly equivalent regardless of the valve type used. Major complications rarely occur in both types of valve.

Funding Acknowledgement

Type of funding sources: None. Self- vs balloon-expanding TF-TAVR

Metabolic treatment of an electrical disease? Beneficial APD/QT prolongation by L-Carnitine in transgenic SQT1 rabbit models

Background

Short-QT syndrome 1 (SQT1) is a genetic cardiac channelopathy caused by gain-of-function mutations (KCNH2-N588K) in HERG/IKr, that leads to shortened QT-interval, increased risk for arrhythmias and sudden cardiac death (SCD). An acquired form of SQTS has been described in patients with primary (genetic) carnitine-deficiency, indicating that carnitine might affect cardiac repolarization.

Purpose

We aimed to investigate potential beneficial (APD/QT-prolonging) effect of L-Carnitine in (genetic) SQTS using transgenic SQT1 rabbits that mimic the human disease phenotype.

Methods

Effects of L-carnitine on cardiac repolarisation were assessed in adult wildtype (WT) and transgenic SQT1 rabbits (KCNH2-N588K) using in vivo ECG and ex vivo Langendorff-perfused whole-heart or isolated ventricular cardiomyocyte action potential (AP) recordings. Effects on ion currents were assessed by whole-cell patch-clamping.

Results

In vivo, the heart-rate corrected QT index (QTi) was prolonged significantly by L-carnitine both in WT (QTi, baseline 102.7%±4.9 vs. L-carnitine 106.9%±6.2, p&lt;0.05, n=12) and SQT1 (QTi, baseline 94.8%±7.4 vs. L-carnitine 99.5%±8.2, p&lt;0.05, n=13), leading to normalisation of QTi in SQT1. Ex vivo, whole-heart monophasic and cellular APs were also significantly prolonged by L-carnitine in WT and SQT1 (change in monophasic APD75, ms, WT +13.9±4.4, SQT1 +9.9±7.0; change in cellular APD90, %, WT +10.4%, SQT1 +10.4%, all p&lt;0.05). As underlying mechanisms, we identified acute effects on the main repolarizing ion currents IKr and IKs: IKr-steady, which is significantly increased in SQT1 contributing to accelerated repolarization, was reduced by L-carnitine (WT: −23%, SQT1: −16%). Moreover, L-carnitine accelerated the deactivation kinetics of IKr - while no change was observed in IKr-tail. In addition, IKs-steady was decreased by L-carnitine in SQT1 and WT cardiomyocytes.

Conclusion

L-carnitine prolongs/normalizes QT and APD in transgenic SQT1 rabbits by decreasing the pathologically increased IKr-steady and also IKs-steady and may therefore serve as potential future anti-arrhythmic therapy in SQTS.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): German Research Foundation (DFG)

Quantitative and qualitative composition of the innate immune response are equally important in wound healing after myocardial infarction

Background

Emergency hematopoiesis (EH) serves as the foundation of monocyte-derived and macrophage (Mφ) driven efferocytosis and ventricular remodeling after myocardial infarction (MI). Excessive myelopoiesis, however, can stipulate maladaptive wound healing and its therapeutic reduction may be a novel approach to preserve cardiac function. All-trans retinoic acid (ATRA) is a pleiotropic modulator of EH and innate immunity shielding hematopoietic stem cells from activation and driving survival and differentiation of myeloid cells.

Purpose

This study aimed to investigate this intriguing interplay of ATRA in wound healing after MI.

Methods

MI was induced by permanent coronary ligation in C57BL/6 mice and treated with daily injections of either ATRA (30mg/kg) or DMSO (vehicle) up to five days, starting 24h after ligation. Flow cytometry (FACS) was used for cell cycle analysis and immunophenotyping of leukocytes in bone marrow (BM), blood and heart. Immunohistochemistry (IH), masson trichrome (MT) staining and echocardiography evaluated inflammatory-fibrotic and functional development. Cytokine expression was analyzed by qPCR in bulk infarct and isolated, polarized Mφ-populations of BM-derived and cardiac resident origin.

Results

On day 2 after MI, EH was significantly reduced in ATRA-treated mice as compared to vehicle controls by means of cell cycle activity (n=6–13 per group; p&lt;0,01) and myeloid cells in BM, blood and infarct tissue (n=5–13; p&lt;0,05). Consequently, mRNA-expression of key inflammatory cytokines, IL-1β and TNFα, was diminished in the infarct tissue in this early phase (n=5–12; p&lt;0,05). These changes, however, failed to preserve cardiac function and ventricular remodeling, 21 days after MI (n=10–11; not significant). By qPCR, non-canonical activation of recruited ATRA-primed monocyte-derived Mφ, was found to propagate a pro-inflammatory phenotype with higher expression of MMP2 and MMP9 in sorted cardiac Mφ (n=4–5; p&lt;0,001). Furthermore, prominent IL-1β-expression in M2-polarized BM-derived Mφ indicated an impaired anti-inflammatory phenotype after ATRA treatment (n=4–6; p&lt;0,05). Strikingly, these changes also occurred in remote myocardium where IH revealed a 2-fold increase of CD11b - positive myeloid cells accompanied by increased expression of TNFα and TGFβ (n=9; p&lt;0,001). MT-staining, performed 21 days after MI, demonstrated an almost 3-fold increase in collagen deposition in remote myocardium of ATRA treated mice in contrast to vehicle controls (n=4–6; p&lt;0,0001).

Conclusion

Despite a beneficial reduction of EH after MI, short-term treatment with ATRA induced profound and persisting changes in the cytokine expression of monocyte-derived Mφ, which significantly altered their function and thus prevented improvements in cardiac function. Our data provide evidence that quantitative and qualitative changes in innate immunity are equally important for cardiac remodeling after MI.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Deutsche Forschungsgemeinschaft

Integrative single cell RNA-sequencing descrambles a substantial divergence of adaptive immune cell identities and transcriptional programs in mouse and human atherosclerosis

Aims

The distinct function of immune cells in human atherosclerosis has been mostly defined by preclinical mouse studies. Contrastingly, the immune cell composition of human atherosclerotic plaques and their contribution to disease progression is only poorly understood. It remains uncertain whether genetic animal models allow for valuable translational approaches.

Methods and results

We performed single cell RNA-sequencing (scRNAseq) to define the immune cell landscape in human carotid atherosclerotic plaques. The human immune cell repertoire was dominated by T cells with a considerable inter-patient variability and an unexpected heterogeneity. We performed bioinformatical integration with 7 mouse data sets and discovered a total of 38 cellular identities, of which some were not conserved between species and exclusively found in mice or humans. Locations, frequencies, and transcriptional programs of immune cells in preclinical mouse models did not resemble the immune cell landscape in human atherosclerosis. In contrast to mice, human plaques were not myeloid- and B cell-dominated and instead contained several T cell phenotypes with hallmarks of T cell memory, dysregulation, exhaustion, and activation. Human immune cells were predominantly enriched for transcriptional programs of hypoxia, glucose, and autoimmunity. In a validation cohort of 43 patients activated immune cell subsets defined by multi-colour flow cytometry associated with cerebral ischemia and coronary artery disease.

Conclusion

Here, we uncover yet undefined immune cell types associating with clinical disease. This leukocyte atlas of human atherosclerosis builds the conceptual basis for subsequent identification of cellular targets for clinical immunomodulatory therapies and risk prediction.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): ERC Starting Grant

Electro-mechanical and mechano-electrical interactions in healthy and drug-induced LQTS rabbit hearts

Funding Acknowledgements

Type of funding sources: Foundation. Main funding source(s): German Research Foundation

Background

Electrical and mechanical heterogeneities and their interactions (electro-mechanical and mechano-electrical coupling; EMC / MEC) are essential for normal cardiac function. Alterations in these can result in increased arrhythmia formation.

Purpose

With this study, we aim to investigate EMC and MEC under physiological and pathological conditions to better understand their roles in arrhythmia development.

Methods

Multi-channel ECG and TPM-MRI were used to measure regional differences in EMC in healthy ("control") and IKr-blocker E-4031 induced acute LQTS ("E-4031") rabbit hearts in vivo. MEC was studied in both groups by acutely changing mechanical function (increased preload by 6 ml/kg BW bolus of NaCl).

Results

In acute LQTS hearts (E-4031 10µg/kg bolus + 1µg/(kg*min) iv), cardiac repolarization was markedly prolonged compared to healthy controls, (p &lt; 0.0001; n = 13), with increased QT-dispersion (Max-Min), a marker for regional heterogeneity of repolarization (p &lt; 0.01; n = 13).

Changing electrical function by E-4031 resulted in changes of mechanical features (EMC): in acute LQTS hearts, diastolic longitudinal velocity (Vz) was reduced in all basal (p = 0.003; n = 19) and 4/6 mid segments (p = 0.006; n = 19). Longitudinal diastolic TTP was prolonged significantly in 5/6 basal and 4/6 mid segments by E-4031. These alterations led to an increased apicobasal heterogeneity of longitudinal contraction duration (basal-apical Vz_dia_TTP [ms] 2.9 ± 10.6 vs. 21.1 ± 21.3; p = 0.01; n = 9).

Increased preload acutely prolonged QTc in both "control" and "E-4031" hearts (‘control’ 156.6 ± 11.6 to 198.3 ± 20.3; p &lt; 0.0001 vs. ‘E-4031’ 193.9 ± 19.6 to 256.0 ± 37.5; p &lt; 0.0001; n = 13) (MEC). This effect was more pronounced in "E-4031" acute LQTS hearts than in healthy hearts (Figure 1; delta QTc [ms] ‘control’ 41.6 ± 14.9 vs. ‘E4031’ 62.1 ± 32.1; p &lt; 0.006, n = 13). QT-dispersion (Max-Min) was increased significantly upon mechanical change only in "E-4031" (‘E-4031’ 25.8 ± 5.5 to 32.7 ± 12.3; p &lt; 0.03, n = 13).

Conclusion

E-4031-induced changes in electrical function resulted in marked alterations in mechanical features via EMC. Similarly, acute changes in mechanical function (increased preload) resulted in electrical changes via MEC. Importantly, QT-prolonging effects of acutely increased preload, as well as its effects on regional heterogeneity of repolarization, were more pronounced in E-4031-induced acute LQTS hearts, indicating that cardiac repolarization in LQTS may be more susceptible to acute MEC effects than in healthy hearts. Acute MEC effects may thus play an additional role in LQT-related arrhythmogenesis. Abstract Figure.

Knockout of purinergic receptor Y13 (P2Y13) results in an improved outcome of metabolic syndrome in mice

 

Metabolic syndrome (MetS) clusters the main risk factors for cardiovascular diseases (CVDs) and endocrine dysfunction. The pathomechanism of MetS is described as local death of hypertrophic adipocytes releasing danger-associated molecular patterns (DAMPs) such as nucleotides (e.g. ADP). This promotes a long term inflammation of adipose tissue via activation of purinergic receptors with a gradual shift towards a pro-inflammatory environment. The ADP receptor P2Y13 is both described in metabolic and immunological processes. These combined characteristics make the P2Y13 an interesting candidate to investigate its role in MetS. Nevertheless, the role of P2Y13R in the pathogenesis of MetS is currently unknown and shall be analyzed in this study.

BMDM isolation and differentiation to Mϕ using M-CSF and subsequent stimulation with medium, LPS and IFNγ or IL4; Expression was quantified using Taqman. Male C57Bl6/J wild-type (WT) and P2Y13-deficient (KO) mice were fed a HFD for 20 weeks; body weight and food consumption were recorded weekly. GTT, ITT and metabolic cages were performed after 15 weeks with euthanization after 20 weeks. In order to distinguish the effect of hematopoetic or somatic cells, mice were lethally irradiated with 9.4Gy and reconstituted with donor bone-marrow (BM) via tail vein injection.

We observed a unique expression of P2Y13R on pro-inflammatory M1 Mϕ. After HFD feeding KO mice showed higher O2 consumption compared to WT mice (AUC of O2 consumption on 2nd day= KO:61620±2261mL/kg vs WT: 53830±916mL/kg, p&lt;0.05). Although KO mice consumed more food compared to WT littermates (KO:5.7±0.5g/d vs WT:3.1±0.1g/d, p&lt;0.0001), they showed significantly decelerated weight gain (e.g.week 15→KO:147,292±5,26% vs WT:180.8±15.9%, p&lt;0.05). Obese KO animals outperformed obese WT littermates in a peritoneal glucose tolerance test (GTT) (2h post-injection (post-i.) →KO:273.7±46.3mg/dL vs WT: 555.0±40.8mg/dL, p&lt;0.05). KO mice on HFD were protected from developing a fatty liver. HFD KO mice receiving WT BM show accelerated weight gain compared to KO mice receiving KO BM (e.g.week 10 WT in KO: 111.2±2.2% vs KO in KO: 102.2±1.2%, p&lt;0.05). In the GTT irradiated KO mice either receiving KO or WT BM are protected from HFD induced impaired glucose homeostasis (45min post-i.; KO→KO:222.1±21.2mg/dL vs WT→KO:232.8±15.9mg/dL vs WT on chow diet:240.4±18.6mg/dL). Contrary, WT mice receiving KO or WT BM developed a glucose resistance comparable to non-irradiated WT mice (45min post-i.; WT→WT:423.8±61.7mg/dL vs KO→WT:434.3±51.1 vs WT on HFD:574.4±7.9).

P2Y13 KO improves the outcome of MetS in mice with improved glucose homeostasis, decelerated weight gain, no fatty liver development and better metabolic turnover. BM transplantation experiments suggest a somatic component as possible explanation of these observations. Given these beneficial metabolic effects, we hypothesize that antagonization of P2Y13R could be a promising therapeutic tool in the field of MetS.

Funding Acknowledgement

Type of funding source: None

P2Y12-dependent regulation of emergency hematopoiesis after myocardial infarction

Introduction

Inflammation is essential for wound healing after myocardial infarction (MI). Leukocytes, especially neutrophils and monocytes, orchestrate removal of necrosis and regulation of tissue remodeling. Beside local recruitment from the blood, leukocyte supply via increased hematopoiesis is of major relevance for post-ischemic myocardial inflammation. Little is known about the pathways that carry the signals for increased demand for leukocytes from the site of injury to upstream hematopoietic stem cells (LSK) in the bone marrow (BM). In this study, we investigate the role of the P2Y12-ADP-receptor mediated regulation for emergency hematopoiesis after MI.

Methods

For standardized MI, a model of permanent coronary ligation was used in C57/Bl6 and P2Y12−/− mice. Changes in plasmatic ADP levels after MI were screened using ELISA, whereas the expression of the P2Y12-ADP-receptor in cell populations isolated from the BM was investigated by qPCR. CFU assays added further functional insight on hematopoietic proliferation in vitro. The effect of P2Y12 on the hematopoietic system after MI was investigated by inhibiting the P2Y12-receptor via prasugrel and compared to inhibition of the thromboxane pathway via acetylsalicylic acid (ASA). Proliferation of LSK in BM and leukocyte composition in blood, BM and infarct tissue after MI were assessed via FACS. Leukocyte composition in the infarcted myocardium was validated by immunohistochemistry. Finally, left ventricular function (LV-EF) and remodeling were investigated by echocardiography.

Results

24 h after MI, we found a peak of plasmatic ADP levels. LSK as upstream hematopoietic progenitors in the BM express a P2Y12-receptor, which was validated on transcriptional and protein level. Whereas ADP stimulation of LSK led to significantly larger colony growth in vitro on the one hand, percentage of cycling LSK were significantly reduced 48 h after MI in P2Y12−/− mice compared to WT mice, assessed by Ki67/DAPI cell cycle analysis. Prasugrel treatment showed similar effects, translating into reduced numbers of downstream hematopoietic progenitors GMP and MDP 72 h after MI. Treatment with ASA however had no significant effect neither on cycling LSK nor progenitor populations. Consequently, decreased medullary hematopoiesis under P2Y12-inhibition led to reduced infiltration of inflammatory cells in the infarct tissue 7 days after MI, finally resulting in significantly improved outcome in terms of LV-EF 3 weeks after MI.

Conclusion

In this study, we demonstrate that P2Y12-mediated signaling is involved in emergency hematopoiesis after MI and advocates post-MI inflammation. In turn, inhibition of P2Y12-mediated signaling contributes to improved wound healing and prevention of adverse cardiac remodeling after MI, which adds a yet unknown mechanism to the success story of modern P2Y12-receptor blockers.

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): Deutsche Forschungsgemeinschaft

Atlas of the immune cell repertoire in human atherosclerotic plaques characterized by single cell RNA-sequencing and multi-color flow cytometry

Rationale

Atherosclerosis is a chronic inflammatory disease that is driven by the accumulation of pro- and anti-inflammatory leukocytes in the intima of affected arteries. Yet, the cellular composition of human atherosclerotic plaques is only poorly understood. Here, we characterized immune cells to human carotid atherosclerotic plaques by multi-color flow cytometry and scRNAseq.

Methods and results

First, we compared a set of previously reported digestion protocols to liberate leukocytes from human carotid plaques after surgical thrombendarteriectomy. One digestion cocktail, containing Collagenase IV and DNase I, was superior regarding cell survival and cell surface marker preservation. Second, leukocytes from 56 surgical specimen were characterized by flow cytometry with a set of 16 parameters and cell surface markers capable of identifying principal hematopoietic leukocyte lineages. This protocol allowed to extract and analyze on average 4x103 viable CD45+ leukocytes from a mean of 988 mg plaque tissue. Surprisingly, we found that atherosclerotic plaques were dominated by T cells with 33.7±2.2% CD4+ T-helper cells and 25.6±2.5% CD8+ cytotoxic T cells. CD11b+ myeloid cells, including monocytes and macrophages, represented only 20.2±4.0% of all CD45+ leukocytes. CD19+B cells and CD56+ NK-cells accounted for 3.9±1.2 and 3.3±0.5%, respectively. TCR-g/d+ T cells and neutrophils were undetectable in atherosclerotic plaques. This cellular composition differed significantly from peripheral blood, but was not relevantly changed between different plaque locations, indicating that macrophage-rich necrotic cores mostly contain dead cells. We confirmed the principal composition of human plaques by single-cell RNA-sequencing from six patients. To allow an estimation of cellular heterogeneity independent of classical cell surface marker assignment, we performed an unsupervised cluster detection algorithm by t-distributed stochastic neighbor embedding (tSNE) and found more than 16 leukocyte clusters with unique cell surface marker expression, suggesting an unexpected high diversity of plaque leukocytes.

Conclusion

We developed an immune cell phenotyping protocol optimized for human carotid plaques. The definition of phenotypes and frequencies in atherosclerotic plaques will allow to build clinical associations between the immune cell composition and clinical outcomes in future.

Funding Acknowledgement

Type of funding source: None

Macrophage-specific IRF5 deficiency stabilizes atherosclerotic plaques in ApoE−/− mice

Background

Interferon regulatory factor (IRF) 5 is a transcription factor promoting inflammatory macrophage polarization (M1 type). Given the central role of macrophages in atherosclerotic plaque development we hypothesized that macrophage specific deletion of IRF5 will protect from atherosclerosis.

Purpose

Investigate whether intrinsic blockade of M1 macrophage polarization ameliorates atherosclerosis

Methods

Female ApoE−/−LysMCre/wtIRF5flox/floxand ApoE−/−LysMwt/wtIRF5flox/floxmice were fed a high cholesterol diet for 3 months, and atherosclerotic plaque size and compositions as well as inflammatory gene expression were analyzed. Mechanistically, IRF5-dependend bone marrow derived macrophage cytokine profiles were tested under M1 and M2 polarizing conditions. Aortic macrophage chimerism in irradiated ApoE−/− mice reconstituted with a mixture of CD45.1+ ApoE−/− (WT) and CD45.2+ ApoE−/− LysMCre/WtIRF5flox/flox(KO) bone marrow was evaluated to distinguish systemic from intra-plaque effects on monocyte/macrophage kinetics.

Results

Macrophage-specific IRF5 deficiency blunted LPS/IFNg-induced IL-1β and TNFα gene expression in vitro. In ApoE−/− mice, macrophage-specific IRF5 deficiency did not alter lesion size in the aortic root but significantly reduced macrophage and lipid contents by about 25% while increasing collagen deposition by over 30%. This was accompanied by relative reductions in gene expressions of pro-inflammatory (IL-1β, IL-6, IL-12) and increases in anti-inflammatory (Mertk, TGFβ, CD206) markers in atherosclerotic aortas of ApoE−/−LysMCre/wtIRF5flox/floxmice. When competing with IRF5 deficient cells in mixed irradiation bone marrow chimeras, IRF5 competent macrophages showed an advantage in accumulating in atherosclerotic aortas as disease progressed independent of monocyte recruitment.

Conclusion

Transcription factor IRF5 promotes a pro-inflammatory response in macrophages leading to vulnerable plaque formation and plaque destabilization, providing genetic evidence for targeting macrophage polarization in atherosclerosis.

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): DFG

Deficiency of the purinergic receptor P2X4 limits atherosclerosis in mice

Introduction

Extracellular nucleotides like ATP promote inflammation as danger signals in various chronic diseases via purinergic receptors. In our previous work we identified P2X4 expression in murine atherosclerotic lesions. Therefore, we hypothesized a contribution of the ATP-P2X4 axis to vascular inflammation in atherosclerosis.

Methods

To investigate the functional role of P2X4 in atherogenesis, wild-type LDL-receptor deficient mice (LDLR−/−) and P2X4-deficient LDLR−/− mice (P2X4−/−LDLR−/−) were fed a high cholesterol diet for 16 weeks. Plaque progression in aortic arches was monitored by echography at intervals of 4 weeks, and leukocyte subsets in blood samples were analysed by flow cytometry. Atherosclerotic lesions were then assessed histologically in aortic root, arch, and abdominal aorta. In order to assess leukocyte recruitment, intravital microscopy was performed after injection of ATP in P2X4−/− or wildtype mice (WT). Regarding transferability to human disease, atherosclerotic plaque from carotid endarterectomy has been stained immunohistochemically for P2X4-receptor expression.

Results

After 16 weeks, P2X4-deficient mice showed significantly reduced atherosclerotic lesions in the aortic root (n=40, LDLR−/−: 0.47 mm2, P2X4−/−LDLR−/−: 0.39 mm2, p=0.04). Ly6C- monocyte count in peripheral blood was higher in P2X4−/−LDLR−/− (n=32, LDLR−/−: 241/μl, P2X4−/−LDLR−/−: 542/μl, p=0.0088), shifting the balance to a more anti-inflammatory subset. Memory-cell generation of CD4-T-cells is significantly higher in knockout-mice, suggesting an involvement of T-helper cells (n=25, LDLR−/−: 27%, P2X4−/−LDLR−/−: 46%, p=0.0003). Peritoneally injected ATP induced leukocyte rolling in WT, but not in P2X4-deficient mice. In human carotid arteries, atherosclerotic plaque shows higher staining for P2X4−/− receptor than not diseased areas.

Conclusion

P2X4-deficiency enhances anti-inflammatory leukocytes in peripheral blood and reduces atherosclerosis. Therefore, blocking the ATP-P2X4 axis may prevent leukocyte recruitment to atherosclerotic lesions and could present a potential new target for anti-atherogenic therapy.

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): This work was supported by a research grant of the German Research Foundation (DFG) to Peter Stachon. Sebastian König was supported by a research grant of the German Cardiac Society (DGK)

Use and outcomes of emergency treatment strategies in patients with aortic valve stenosis

Introduction and aim

Current emergency treatment options for severe aortic valve stenosis include surgical aortic valve replacement (SAVR), transcatheter aortic valve replacement (TAVR) and balloon valvuloplasty (BV). So far no larger patient population has been evaluated regarding clinical characteristics and outcomes. Therefore we aimed to describe the use and outcome of the three therapy options in a broad registry study.

Method and results

Using German nationwide electronic health records, we evaluated emergency admissions of symptomatic patients with severe aortic valve stenosis between 2014 and 2017. Patients were grouped according to SAVR, TAVR or BV only treatments. Primary outcome was in-hospital mortality. Secondary outcomes were stroke, acute kidney injury, periprocedural pacemaker implantation, delirium and prolonged mechanical ventilation &gt;48 hours. Stepwise multivariable logistic regression analyses including baseline characteristics were performed to assess outcome risks.

8,651 patients with emergency admission for severe aortic valve stenosis were identified. The median age was 79 years and comorbidities included NYHA classes III-IV (52%), coronary artery disease (50%), atrial fibrillation (41%) and diabetes mellitus (33%). Overall in-hospital mortality was 6.2% during a mean length of stay of 22±15 days. TAVR was the most common treatment (6,357 [73.5%]), followed by SAVR (1,557 [18%]) and BV (737 8.5%]).

Patients who were treated with TAVR or BV were significantly older than patients with SAVR (mean age 81.3±6.5 and 81.2±6.9 versus 67.2±11.0 years, p&lt;0.001), had more relevant comorbidities (coronary artery disease 52–91% vs. 21.8%; p&lt;0.001), worse NYHA classes III-IV (55–65% vs. 34.5%; p&lt;0.001) and higher EuroSCORES (24.6±14.3 and 23.4±13.9 vs. 9.5±7.6; p&lt;0.001) than SAVR patients. Patients treated with BV only had the highest in-hospital mortality compared with TAVR or SAVR (20.9% vs. 5.1 and 3.5%; p&lt;0.001).

Compared with BV only, SAVR patients (adjusted odds ratio [aOR] 0.25; 95% confidence interval [CI] 0.14–0.46; p&lt;0.001) and TAVR patients (aOR 0.37; 95% CI 0.28–0.50; p&lt;0.001) had a lower risk for in-hospital mortality.

Conclusion

In-hospital mortality for emergency patients with symptomatic severe aortic valve stenosis is high. Our results showed that BV only therapy was associated with highest mortality, which is in line with current research. Yet, there is a trend towards more TAVR interventions and this study might imply that balloon valvuloplasty alone is insufficient. The role of BV as a bridging strategy to TAVR or SAVR needs to be further investigated.

Funding Acknowledgement

Type of funding source: Public hospital(s). Main funding source(s): Heart Center Freiburg University, Department of Cardiology and Angiology I, Faculty of Medicine, University of Freiburg, Freiburg, Germany

Sirtuin 4 contributes to heart failure development by increasing mitochondrial oxidative stress

 

Sirtuin 4 (SIRT4) is a mitochondrial NAD+-dependent deacylase which inhibits the oxidation of glucose and fatty acids, and has been implicated in the regulation of oxidative stress. Given the importance of cardiac energy depletion and ROS during heart failure development, we aimed to define the role of SIRT4 in the development of heart failure. Mice with deletion (SIRT4−/−) or overexpression (SIRT4 TG) of SIRT4 were subjected to transverse aortic constriction (TAC) for 12 weeks or underwent sham procedures. Using echocardiography, ejection fraction (EF) was not different between SIRT4 TG and WT mice subjected to sham operations. In contrast, TAC induced a more pronounced decrease in EF (35% vs. 51%; p&lt;0.05), and a more pronounced increase in LV endsystolic diameter (4.5mm vs. 3.6mm; p&lt;0.05) and myocardial fibrosis (2.2-fold; p&lt;0.05) in SIRT4 TG mice compared to WT mice. Myocardial levels of the lipid peroxidation product 4-hydroxynonenal were increased in WT mice following TAC and were synergistically increased in SIRT4 TG mice following TAC (+66% vs. WT TAC; p&lt;0.05). Administration of the mitochondria-targeted antioxidant MitoQ normalized 4-hydroxynonenal levels, markedly attenuated the decline in EF and almost normalized endsystolic LV diameter in SIRT4 TG mice following TAC. Cardiac function and morphology were unaffected in SIRT4−/− mice during normal or increased workload conditions. Thus, while SIRT4 is not required to maintain cardiac function even in response to increased energy demands, increased expression of SIRT4 accelerates the development of heart failure following TAC, at least in part due to increased mitochondrial oxidative stress.

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): German Research Foundation

Hospital volumes and the likelihood of stent implantation among patients undergoing catheterization of the left heart: more is more?

Background

Percutaneous coronary intervention (PCI) is an established procedure, but recent studies analyzing the indication for stenting are going to change clinical practice. Previous studies suggested that hospital volume is inversely related to in-hospital mortality but its impact on likelihood of stent implantation and the number of stents remains unclear.

Purpose

There is a conflict of objectives between nationwide care including short transfer and intervention times and a few large centers with maximum technology and experience. We examine the effect of hospital volume on in-hospital mortality, likelihood of stent implantation, number of stents, length of hospital stay, and reimbursement in a recent nationwide cohort from Germany.

Methods

Using German national electronic health records, all patients who underwent coronary angiography with a documented coronary artery disease were identified by ICD and OPS codes. Risk-adjustment was applied using a predefined set of patient characteristics to account for differences in the risk factor composition of the patient populations between centers.

Results

In 2017, a total of 528,188 patients with a documented coronary artery disease underwent coronary angiography in Germany. Mean age was 69.8 years and 29.3% of patients were female. 55% of all patients received PCI, with a mean number of 1.01 stents implanted per patient. In-hospital mortality was 2.9%, length of hospital stay was 6.5 days and mean reimbursement was €5,531. Multivariable regression analyses showed a positive linear association between hospital volumes and the likelihood of stent implantation (p=0.003) as well as the number of implanted stents (p=0.020). No association was found between hospital volumes and in-hospital mortality (p=0.105), length of hospital stay (p=0.201) or reimbursement (p=0.108). Inspection of the non-linear impact of procedure volumes on stent implantation practices indicates a ceiling effect in the volume-outcome relationship: implantation likelihood and number of stents per patient are lowest in centers with less than 100 procedures per year (34.4% and 0.62, respectively). Then, implantation likelihood and number of stents constantly increase until the volume category of 500 procedures per year and center. For centers with &gt;500 procedures per year, the likelihood of stent implantation and the number of implanted stents remained relatively constant (about 60% and 1.07, respectively).

Conclusion

Patients undergoing coronary angiography in low-volume centers are less frequently subject to PCI but at comparable risk for in-hospital mortality. Furthermore, the data suggest that more complex cases are treated in high volume centers with consistent mortality rates and thus constant safety is ensured in high volume hospitals. Thresholds are discussed.

Impact of hospital volumes on PCI

Funding Acknowledgement

Type of funding source: None

Loss of platelet BMP4 reduces vascular inflammation and ameliorates vascular remodelling after carotid wire injury

Background

Bone morphogenic proteins (BMPs) are members of the TGFβ superfamily. They have distinct functions during hemostasis and play a central role in various pathologic conditions, including cardiovascular diseases. Recent findings demonstrate that BMPs are also expressed in platelets. However, their function is poorly understood. Here, we investigate the role of platelet BMP4 during vascular inflammation and vascular remodelling.

Methods

BMP4 floxed mice were crossed with PF4 Cre mice to generate platelet-specific deletion of BMP4 (BMP4Plt−/−). Intravital microscopy of mesenteric veins was performed to evaluate leukocyte adhesion upon stimulation with TNFα. Expression of adhesion molecules and chemokines were analysed by RT-PCR and Western Blot. P-selectin and platelet-leukocyte aggregates were evaluated using flow cytometry. For carotid wire injury, BMP4Plt−/− were further crossed with LDLr−/− mice (BMP4Plt−/−/LDLr−/−). At 8 weeks of age, BMP4Plt−/−/LDLr−/− mice and control littermates received a 2-week diet containing 15.8% wt/wt fat and 1.25% cholesterol. Carotid wire injury was performed at the age of 10 weeks. Re-endothelialisation and neointimal hyperplasia were evaluated.

Results

Platelet morphology and function did not differ between BMP4Plt−/− and control mice. Stimulation with TNFα resulted in increased rolling and adherence of leukocytes to the vessel wall which was reduced in BMP4Plt−/− mice (175±25 versus 50±7 rolling cells and 16±3 versus 7±2 adherent cells, respectively). Expression of P-selectin, adhesion molecules and the chemokines RANTES and PF-4 were reduced in BMP4Plt−/− mice. Platelet activation by thrombin was reduced in BMP4Plt−/− mice, resulting in diminished P-Selectin and JONA expression. Furthermore, monocyte infiltration and circulating leukocyte-platelet complexes were reduced in BMP4Plt−/− mice. Loss of platelet BMP4 prevented neointima formation after carotid wire injury (4.2x104±0.9x104μm2 versus 14.9x104±2.2x104μm2 in BMP4Plt−/−/LDLr−/− and control mice, respectively). Interestingly, endothelial regeneration after injury was decelerated in BMP4Plt−/− mice. This is further demonstrated in-vitro, where platelet BMP4 promoted endothelial cell proliferation and migration.

Conclusion

Platelet-BMP4 deficiency reduced vascular inflammation and ameliorated intima hyperplasia after wire injury. This is partly mediated by inhibition of platelet activation, reduced expression of adhesion molecules and inflammatory response. Our finding suggests that BMP4 is a promising target for the treatment of vascular inflammation and restenosis.

Funding Acknowledgement

Type of funding source: Private grant(s) and/or Sponsorship. Main funding source(s): Else-Kröner Fresenius Foundation; German Cardiac Society

Blood transfusion and ischaemic outcomes according to anemia and bleeding in patients with non-ST-segment elevation acute coronary syndromes: Insights from the TAO randomized clinical trial

BACKGROUND

The benefits and risks of blood transfusion in patients with acute myocardial infarction who are anemic or who experience bleeding are debated. We sought to study the association between blood transfusion and ischemic outcomes according to haemoglobin nadir and bleeding status in patients with NST-elevation myocardial infarction (NSTEMI).

METHODS

The TAO trial randomized patients with NSTEMI and coronary angiogram scheduled within 72h to heparin plus eptifibatide versus otamixaban. After exclusion of patients who underwent coronary artery bypass surgery, patients were categorized according to transfusion status considering transfusion as a time-varying covariate. The primary ischemic outcome was the composite of all-cause death or MI within 180 days of randomization. Subgroup analyses were performed according to pre-transfusion hemoglobin nadir and bleeding status.

RESULTS

12,547 patients were enrolled. Among these, blood transfusion was used in 489 (3.9%) patients. Patients who received transfusion had a higher rate of death or MI (29.9% vs. 8.1%, p<0.01). This excess risk persisted after adjustment on GRACE score and nadir of hemoglobin (HR 3.36 95%CI 2.63-4.29 p<0.01). Subgroup analyses showed that blood transfusion was associated with a higher risk in patients without overt bleeding (adjusted HR 6.25 vs. 2.85; p-interaction 0.001) as well as in those with hemoglobin nadir > 9.0 g/dl (HR 4.01; p-interaction<0.0001).

CONCLUSION

In patients with NSTEMI, blood transfusion was associated with an overall increased risk of ischaemic events. However, this was mainly driven by patients without overt bleeding and those hemoglobin nadir > 9.0g/dl. This suggests possible harm of transfusion in those groups.

Influence of extracorporeal membrane oxygenation on serum microRNA expression

Objective

To date, no biomarkers have been established to predict haematological complications and outcomes of extracorporeal membrane oxygenation (ECMO). The aim of this study was to investigate the expression of a panel of microRNAs (miRNAs), which are promising biomarkers in many clinical fields, in patients before and after initiating ECMO.

Methods

Serum miRNA levels from 14 patients hospitalized for acute respiratory failure and supported with ECMO in our medical intensive care unit were analysed before and 24 hours after ECMO. In total, 179 serum-enriched miRNAs were profiled by using a real-time PCR panel. For validation, differentially expressed miRNAs were individually quantified with conventional real-time quantitative PCR at 0, 24, and 72 hours.

Results

Under ECMO support, platelet count significantly decreased by 65 × 103/µL (25th percentile = 154.3 × 103/µL; 75th percentile = 33 × 103/µL). Expression of the 179 miRNAs investigated in this study did not change significantly throughout the observational period.

Conclusions

According to our data, the expression of serum miRNAs was not altered by ECMO therapy itself. We conclude that ECMO does not limit the application of miRNAs as specific clinical biomarkers for the patients’ underlying disease.

4323Detection of early inflammation in myocarditis by molecular magnetic resonance imaging of activated platelets

Introduction

A noninvasive imaging strategy for diagnosis and localization of early myocarditis would be of great clinical interest. However, resolution of current imaging techniques is limited. Platelets play an important role in inflammatory processes but the role in myocarditis is unknown. Therefore, the aim of this project was to examine the role of platelets in myocarditis and establish a sensitive non-invasive molecular MRI in-vivo imaging strategy for diagnosis of myocarditis with a contrast agent against activated platelets in mice.

Methods

Myocarditis was induced by subcutaneous injection of an emulsion of porcine cardiac myosin and complete freud's adjuvant (CFA) in Balb/c mice. Inflammatory activity was targeted with a contrast agent against activated platelets consisting of microparticles of iron oxide (MPIO) conjugated to a single chain antibody directed against ligand-induced binding sites (LIBS) on activated glycoprotein IIb/IIIa (=LIBS-MPIO). In comparison, we applied an unspecific control antibody linked to microparticles of iron oxide (control-MPIO) and injected LIBS-MPIO to mice subjected to incomplete freud's adjuvant (iCFA). All imaging results were correlated to immunohistochemistry findings.

Results

Histological evaluation showed significantly higher binding of LIBS-MPIOs to platelet enriched, CD41-positive inflamed myocardium two days after induction of myocarditis in comparison to later time points (7d, 14d, 21d) (p<0.05) and control-MPIO (p<0.05) injection. In iCFA injected mice no significant LIBS-MPIO binding was found (p<0.05). In 3D in-vivo MRI we could specifically detect focal signal effects in LIBS-MPIO injected mice 2 days after induction of myocarditis, whereas in control-MPIO injected mice no signal effect was visible. Quantification of the myocardial MRI signal confirmed a signal decrease after LIBS-MPIO injection and significant fewer signals in comparison to control-MPIO injection (p<0.05).

As a perspective, we also found CD41 positive areas in histology of human myocarditis specimens.

Conclusions

Platelets are involved in the inflammation of myocarditis. Molecular MRI with LIBS-MPIO can image them at an early time point. This noninvasive imaging strategy is of clinical interest for both diagnostic and prognostic purposes, and highlights the potential of molecular MRI for characterization of cardiovascular pathologies such as myocardial inflammation.

P733Cholesterol uptake triggers macrophage proliferation in the plaque

Background

Guidelines recommend cholesterol lowering for primary and secondary prevention of cardiovascular disease. While lipid lowering has been reported to induce plaque regression, the underlying mechanisms have remained speculative.

Purpose

We hypothesize that lipid uptake triggers local macrophage proliferation in the plaque, and conversely, statin treatment inhibits local macrophage proliferation leading to plaque regression.

Methods

Mixed bone marrow chimeras were generated in LDLR−/− mice reconstituted with wild type and scavenger receptor deficient or cholesterol exporter deficient bone marrow cells to study cell autonomous effects on macrophage proliferation. APOE*3-Leiden.huCETP mice with established atherosclerosis were randomized to three groups: Continued cholesterol diet, cholesterol diet supplemented with 0.01% atorvastatin, and cholesterol free diet for 4 weeks to study mechanisms of plaque regression.

Results

Proliferation of scavenger receptor A and CD36 deficient macrophages with impaired lipid uptake was reduced by 30–50% in the plaque, while ABCA1/ABCG1 exporter deficiency resulted in cholesterol overloading and apoptosis. Oral atorvastatin treatment decreased total plasma cholesterol levels by 50% to the same extend as cholesterol free diet feeding in APOE*3-Leiden.huCETP. Cholesterol lowering resulted in a 50% reduction in local macrophage proliferation and plaque regression with reduced macrophage and lipid contents and increased collagen. GFP bone marrow reconstitution of APOE*3-Leiden.huCETP mice in which the aortas were shielded from irradiation showed infiltrating monocytes to contribute only 11% to the plaque macrophage pool during plaque progression, thereby underscoring the relevance of targeting macrophage proliferation for plaque regression. Finally, rates of macrophage proliferation in human carotid artery plaques correlated with serum LDL-cholesterol levels, in line with our experimental studies.

Conclusion

Foam cell formation in atherosclerotic plaques triggers their proliferation. Targeting macrophage proliferation leads to plaque regression.

P1694Sex is not an independent predictor of ischemic outcomes or bleeding in NSTEMI patients undergoing percutaneous coronary intervention. Insights from the TAO trial

Background

There is uncertainty regarding whether female sex is an independent predictor of adverse outcomes in acute coronary syndromes (ACS).

Purpose

We sought to describe and compare ischemic and bleeding outcomes between men and women with Non–ST-segment–Elevation (NSTE) ACS enrolled in the large Treatment of Acute coronary syndromes with Otamixaban (TAO) trial in which antithrombotic treatment was standardized and a systematic invasive approach was performed.

Methods

The TAO trial randomized moderate to high-risk NSTE-ACS patients with diagnostic coronary angiography planned in the first 72 hours to heparin plus eptifibatide versus otamixaban. This post-hoc analysis describes ischemic (all-cause death, new myocardial infarction, stent thrombosis within 180 days of randomization) and bleeding outcomes (TIMI major and minor bleeding within 30 days of randomization) according to sex.

Results

Of 13,229 patients with NSTE-ACS randomized in 55 countries, 3,980 (30.1%) were female and 9,249 (69.9%) were male. Mean age was 64.8±11.0 and 60.7±11.1 years, respectively. The prevalence of diabetes (34.0% vs. 25.8%), hypertension (80.8% vs. 67.0%), and hypercholesterolemia (55.9% vs. 52.2%) was higher among women compared with men but current smoking (21.5% vs. 38.7%) and history of previous MI were more frequent in males (15.5% vs. 20.7%).

Females experienced a higher incidence of both ischemic outcomes (10.2% vs. 9.1%; OR=1.15; 95% CI, 1.01–1.30; p=0.034) and bleeding events (4.1% vs. 3.4%; OR=1.23; 95% CI, 1.02–1.49; p=0.029). Bleeding risk and CV death were particularly increased in women younger than 50 years, compared to males of the same age, at 5.5% vs. 1.4% (OR=4.00; 95% CI, 2.13–7.69; p=0.034) and 1.7% vs. 0.5% (OR=4.35; 95% CI, 1.02–20.00; p=0.02), respectively. No difference in either outcome was found between women and men between 50 and 80 years old. Above 80 years, women experienced a lower rate of bleeding (3.9% vs. 7.8%; OR=0.47; 95% CI, 0.23–0.88; p=0.024) but a similar rate of in ischemic events (16.0% vs. 17.2%; OR=0.92; 95% CI, 0.63–1.33; p=0.67).

After adjustment for age, body weight, diabetes mellitus, prior PCI, serum creatinine, presenting systolic blood pressure, elevated biomarker at presentation, heart failure, the risk of ischemic (OR=1.03; 95% CI, 0.89–1.18; p=0.71) and bleeding events (OR=1.05; 95% CI, 0.85–1.33; p=0.65) were similar between men and women.

Conclusions

In this large international randomized trial of NSTE-ACS with standardized invasive management, women (particularly those younger than 50 years) experienced higher risks of ischemic and bleeding events than men, but the difference was not sustained after adjustment. In this population, sex was not an independent predictor of adverse outcomes in NSTE-ACS. The type of ACS (NSTE-ACS) and routine invasive management in women and men may explain this absence of difference.

Acknowledgement/Funding

The TAO trial was sponsored and funded by SANOFI. The present analysis was supported by the RHU iVASC grant “#ANR-16-RHUS-00010”

P5381Lack of sirtuin 5 aggravates myocardial ischemia reperfusion injury

Sirtuin 5 (SIRT5) is a mitochondrial NAD+-dependent protein deacylase which regulates the enzymatic activity of numerous mitochondrial proteins due to increased succinylation and malonylation, including enzymes of energy substrate oxidation and mitochondrial antioxidant enzymes. Since energy depletion and mitochondrial oxidative stress contribute to myocardial IR injury, it was our objective to evaluate the potential role of SIRT5 in IR injury. In regular Langendorff heart perfusions, 8 week-old cardiomyocyte-selective SIRT5−/− mice showed no difference in LV developed pressure or dp/dt max compared to wildtype mice. However, recovery of LV developed pressure and dp/dt max following 25 min of ischemia was lower by 34% and 20% in SIRT5−/− mice compared to WT mice, respectively. In contrast, postischemic recovery of cardiac function was not impaired and even improved in mice with cardiomyocyte-selective overexpression of SIRT5 compared to WT mice undergoing IR. Mitochondrial H2O2 generation was significantly increased in SIRT5−/− mice compared to WT mice following IR, and mitochondria-targeted antioxidant treatments (MnTBAP or SS-31) during heart perfusion completely normalized recovery of contractile parameters in SIRT5−/− mice following IR. In conclusion, SIRT5 is not required to maintain cardiac function under physiological conditions. However, lack of SIRT5 aggravates myocardial IR injury, likely by increasing mitochondrial oxidative stress. SIRT5 agonism may thus represent a potential therapeutic strategy to attenuate myocardial IR injury.

5221Knockout of purinergic receptor Y13 (P2Y13) results in an improved outcome in metabolic syndrome in mice

Background

Metabolic syndrome clusters the main risk factors for cardiovascular diseases and endocrine dysfunction. Novel studies show that the important underlying mechanism is a long term inflammation of adipose tissue with a gradual shift from the anti-inflammatory M2 towards the pro-inflammatory M1 macrophages (pathognomonic). Massive hypertrophy induces adipocyte death, which releases DAMPs like nucleotides recognized by purinergic receptors orchestrating ongoing inflammatory process. Interestingly, we found Gi coupled P2Y13R only expressed on M1 macrophages, not in M0 (unstimulated) and M2 macrophages.

Nevertheless, the role of P2Y13R in the immune system and especially macrophages is currently unknown. Given its pivotal role in central metabolic processes (P2Y13R has been described in insulin secretory signalling) together with its unique expression in its pathognomonic inflammatory macrophage subtype makes it an interesting candidate to investigate its role in metabolic syndrome.

Purpose

Due to the unique expression of P2Y13R on M1 macrophages we hypothesise an improved outcome in a high-fat diet induced metabolic syndrome by interfering with the P2Y13 signalling cascade.

Methods

BMDM differentiation to macrophages using M-CSF and subsequent stimulation with medium (M0), LPS and IFNγ (M1) or IL4 (M2); Expression of P2Rs quantified using Taqman qPCR.

Male C57Bl6/J wild-type (WT) and P2Y13-deficient (KO) mice were fed with a high-fat diet (HFD) for 20 weeks; On week 15 we performed the ITT, on week 16 the GTT. Metabolic performance was monitored by metabolic caging.

Results

We observed a unique expression of P2Y13R on M1 macrophages. Adult P2Y13-deficient mice showed a higher O2 consumption compared to adult C57Bl6/J wild-type mice (AUC of O2 consumption 2nd day= KO: 61620±2261mL/kg vs WT: 53830±916.1mL/kg, p=0.0331). Although both P2Y13−/− mice and WT littermates consumed comparable amount of food (daily food intake per mouse → KO: 3.97±0.25g vs WT: 3.76±0.18g), P2Y13 deficient animals showed significantly decelerated weight gain (e.g. on week 15 → KO: 142±2% (n=10) vs WT: 198±5% (n=10), p<0.0001). Obese P2Y13−/− animals outperformed obese WT littermates in a peritoneal glucose tolerance test (2h after glucose injection → KO: 272.9±21.0 mg/dL (n=10) vs WT: 532.6±21.2 (n=10) mg/dL, p<0.0001). There was no difference in the cell amount of stromal vascular fraction cells.

Conclusion

Global P2Y13 deficiency leads to an improved outcome in metabolic syndrome with an increased protection against developing an insulin resistance as shown through an improved glucose tolerance and basal glucose levels, a decelerated weight gain despite comparable food consumption and a better metabolic turnover. Observing these beneficial metabolic improvements, we hypothesise that antagonization of P2Y13R could be a promising therapeutic target in the field of metabolic syndrome.

P6291Post-myocardial infarction activation of P2X7 dependent inflammasome is crucial to develop an appropriate scar integrity

Introduction

Cardiovascular diseases are the main cause of death worldwide. Acute ischemia results in cell death of cardiomyocytes accompanied with the release of so called damage associated molecular patterns (DAMPs) such as nucleotides. High concentration of ATP in the extracellular fluid leads to the opening of the ionotropic purinergic receptor P2X7. The following transmembranous ion flux triggers the assembly of the NLRP-3 inflammasome and proteolytic caspase-1 activation which cleaves pro-IL-1β and provokes the release of fully active pro-inflammatory IL-1β. Myocardial scar formation can be divided into an early remodelling IL-1β-dependent and a late scar forming TGFβ phase. Both phases negatively regulate each other. The current stuy aimed to investigate the role of this master regulator of NLRP3 inflammasome assembly P2Y7 in myocardial remodeling during prolonged ischemic conditions.

Methods

10 weeks old P2X7 knock-out and C57Bl6/J mice received a full ligation of the left anterior descending (LAD) artery. Mice three and seven days post-infarction underwent echocardiography. Myocardial scar formation was assessed by histological staining and flow cytometry. Furthermore caspase-1 activity was measured using FLICA in histology. Gene expression was assessed using TaqMan realtime PCR.

Results

Macrophages in the myocardial infarct area showed high P2X7 expression by Co-staining with fluorescent antibodies against F4/80, CD68 and P2X7. Intriguingyl P2X7 deficient animals showed a significantly worse survival rate in a Kaplan-Meier survival analysis compared to wt littermated with LAD ligation (Mortality after 21 days P2X7+/+ 50%; P2X7−/− 100%, p<0.05). Cause of death assessed by autopsy was myocardial rupture in P2X7−/− mice. Accordingly histological analysis revealed a less compact infarct area in P2X7 knock-out animals with abundant coagulation necrosis. In agreement with that we observed a thickened infarcted anterior wall by echocardiography in P2X7 animals. Furthermore whereas the infarcted area of P2X7 competent mice showed high signals for active caspase-1 in histology, we were not able to detect any signal of caspase-1 activity in P2X7 deficient mice. In coherence with this observation we detected a premature increased TGFβ gene transcript upregulation in infarct tissue of P2X7 deficient animals.

Conclusion

The knockout of the NLRP3 inflammasome activating P2X7 receptor impairs the outcome after myocardial infarction by reduced monocyte infiltration and deranged scar formation. Disruption of the fine-tuned IL-1β/TGFβ sequence with an early block of IL-1β signaling and premature TGFβ activation could explain the missing clean-up of necrotic debris and impaired scar formation. Taken together these findings highlight the importance of an early inflammasome phase during myocardial scar formation.

P3480Tissue-specific regulation of the mitochondrial proteome by adiponectin receptor 1

Lack of the adiponectin target receptor adiponectin receptor 1 (AdipoR1) impairs gene expression of mitochondrial OXPHOS proteins due to impaired AMPK-SIRT1-PGC-1α signaling. Since decreased adiponectin serum levels in diabetes mellitus should thus compromise AdipoR1 signaling, we hypothesized that impaired AdipoR1 signaling may causally contribute to typically observed mitochondrial defects in diabetes complications. Thus, we performed comparative proteomics in cardiac, renal and hepatic tissue of AdipoR1−/− mice using LC-MS/MS. Using principal component analysis, heatmapping and hierarchical clustering, a significant separation of genotypes was observed across tissues. Enrichment analysis of differentially expressed proteins revealed disproportionate representation of proteins involved in oxidative phosphorylation, TCA cycle and fatty acid oxidation in all tissues. While 121 or 98 or 78 proteins were differentially regulated in cardiac or renal or hepatic tissue, respectively, only 15 proteins were regulated in the same direction across all tissues. Pathway analysis identified HNF4, NRF1, LONP, RICTOR, SURF1, insulin receptor and PGC-1α as most likely upstream regulators. Importantly, we found a dramatic downregulation of AdipoR1 expression in heart (−70%), liver (−90%) and kidney (−80%; all p<0.05) of high fat-fed and prediabetic non-transgenic mice compared to low fat-fed mice. In addition and beyond diabetes, AdipoR1 expression was also decreased in endstage failing hearts of non-diabetic human subjects compared to non-failing donor hearts. Thus, we conclude that AdipoR1 signaling regulates mitochondrial protein composition across all tissues in a functionally conserved, yet molecularly distinct, manner. Impaired AdipoR1 signaling may causally contribute to mitochondrial defects in diabetic complications and even human heart failure.

P6346Purinergic receptor Y6 (P2Y6) deficiency impairs left ventricular function

Introduction

Cardiomyopathies due to pathological remodelling are the most common myocardial disorders and leading indication for heart transplant in young adults. Cardiomyocytes rely on sessile macrophage phagocytosis for cell homeostasis. Purinergic receptor Y6, selectively binding to UDP, promotes phagocytosis and is involved in several tissue-remodelling processes.

We hypothesize a critical role of P2Y6 in the maintenance of cardiac tissue homeostasis in vivo.

Methods

Echocardiography was performed on male C57Bl6 wild-type (WT) and P2Y6-deficient (KO) mice at different ages up to 20 weeks. In addition, WT and KO mice underwent bone marrow transplantation. For histological analysis, hearts from WT and KO mice were stained with HE, Masson's trichrome, wheat germ agglutinin, CD11b, LC3B and TUNEL. Cardiac ultrastructure of WT and KO hearts was investigated by electron microscopic imaging. Furthermore, uptake of fluorescent pHrodo bioparticles by WT and KO bone marrow derived macrophages (BMDMs), either in presence or absence of specific P2Y6 agonist UDP or full antagonist MRS2578, was measured in vitro.

Results

KO mice were significantly impaired in their LV function by reduced ejection fraction (WT: 57.37±1.27%, n=13, KO: 44.13±1.09%, n=16, p<0.0001), stroke volume (WT+: 39.25±1.94μl, n=13, KO: 33.57±1.94μL, n=16, p<0.05), and cardiac output (WT: 20.79±1.11 mL/min, n=13, KO: 17.84±0.85 mL/min, n=16, p<0.05). A long-term follow-up revealed progressive impairment of the cardiac function (4 w: WT: 62.07±1.11%, n=5, KO: 48.73±1.03%, n=10, p<0.0001; 6 w: WT: 54.29±1.88%, n=5, KO: 44.61±1.4%, n=10, p<0.01; 8 w: WT: 56.43±1.44%, n=5, KO: 44.72±0.89%, n=10, p<0.0001). Echocardiography 6 weeks after bone marrow transplantation demonstrated convalescence upon reconstitution with WT bone marrow (WT in KO: 46.19±2.68%, n=3 vs KO in WT: 38.40±1.26%, n=3). No major differences with regard to morphology, cell size, collagen deposition, leukocyte infiltration or apoptosis were observed in histology. However, LC3B expression was increased in KO mice (mean fluorescent area: WT: 191.1±19.93μm2, n=5, KO: 261.2±18.34μm2, n=10, p<0.05). Electron microscopic imaging revealed a distinctly impaired ultrastructure with T-tubule remodelling, mitochondrial derangement and abnormal numbers of autophagosomes in KO hearts. In vitro, fluorescent particle phagocytosis by BMDMs was completely blocked after treatment with MRS2578.

Conclusion

Global P2Y6 deficiency leads to a progressive cardiomyopathy in mice, mainly characterized by an impaired left ventricular function and ultrastructural irregularities. Its exacerbation seems to be prevented by reconstitution with WT bone marrow. For the underlying mechanism, we conclude a deranged cardiomyocyte homeostasis in KO animals due to defective phagocytic activity of resident macrophages. Potential induction of cardiac clearance via P2Y6 signalling could be a promising therapeutic target in the field of cardiomyopathies.

P1939Tumor necrosis factor receptor-associated factor 5 (TRAF-5) deficiency exacerbates diet-induced adipose tissue inflammation and aggravates metabolic syndrome in mice

Introduction

Many clinical and experimental observations have established an association between visceral obesity and chronic adipose tissue inflammation. Potent pro-inflammatory mediators such as TNFα, CD40 and IL-1β are regulated by Tumor necrosis factor (TNF) receptor-associated factors (TRAFs). TRAF5 deficiency accelerates atherogenesis in mice by increasing inflammatory leukocyte recruitment. Since inflammatory cell invasion is also a prerequisite of adipose tissue inflammation, we tested the hypothesis that deficient TRAF5 signaling aggravates adipose tissue inflammation and its metabolic complications in a murine diet-induced obesity (DIO) model.

Purpose

We aimed to clarify the role of TRAF5 in adipose tissue inflammation and metabolic syndrome.

Methods

TRAF5−/− mice and gender- and age-matched wild-type (WT) mice consumed a high fat diet (HFD, 45%kcal from fat) or a matched low-fat diet (LFD, 10%kcal from fat) for 18 weeks to induce DIO and adipose tissue inflammation. All mice were then subjected to subsequent analysis, including glucose and insulin tolerance testing, body composition assessment by MRI imaging, flow cytometry, gene expression of different tissues, plasma analysis and histology. Finally, we studied if TRAF5 expression was associated with metabolic syndrome in humans by analyzing plasma and adipocytes samples from 62 patients of the Tumor-Necrosis-Factor Receptor Associated in Cardiovascular Risk Study (TRAFICS).

Results

TRAF5 expression was significantly attenuated in isolated WT-adipocytes and WT-macrophages after 18 weeks of HFD compared to LFD-fed controls. TRAF5−/− mice on HFD gained significantly more weight compared to TRAF5-competent mice and showed an aggravated metabolic phenotype, including impaired insulin tolerance, hyperinsulinemia and increased fasting glucose plasma levels. The weight gain in TRAF5−/− mice was attributable to a significant increase in adipose tissue and liver weight. Further analysis of the visceral adipose tissue revealed enhanced macrophage accumulation and increased pro-inflammatory CD11c+ subset polarization in HFD-fed TRAF5−/− mice. In line with an increased migratory capacity of inflammatory cells, we observed enhanced peritoneal invasion of leukocytes and subsets in TRAF5−/− mice. Accordingly, TRAF5 deficiency increased inflammatory cytokine expression and ameliorated parameters of insulin sensitivity in adipose tissue. Finally, patients with metabolic syndrome displayed decreased TRAF5 expression in blood and adipocytes compared to humans without metabolic syndrome.

Conclusion

We show that genetic deficiency of TRAF5 aggravates metabolic syndrome in murine diet-induced obesity. Enhanced accumulation of leukocytes subsets in adipose tissue serves as the likely mechanism. We conclude that TRAF5 signaling properties may favorably affect metabolic disease.

Acknowledgement/Funding

Forschungskommission Medizinische Fakultät Universität Freiburg, MOTI-VATE Promotionskolleg der Medizinischen Fakultät Freiburg (EKFS)