RNA-sequencing reveals significant differences in the inflammatory response of iPSC-derived endothelial cells from ACS patients and healthy controls

Background

Coronary artery disease (CAD) and cardiovascular diseases (CVD) in general still represent the leading cause of death worldwide. As a multifactorial disease entity, genetic predisposition and lifestyle strongly impact disease development and progression. Here, induced pluripotent stem cells (iPSC) are an ideal tool to differentiate (epi-)genetic from lifestyle disease risk modulation and identify the underlying molecular mechanisms.

Aim

This study aims to determine differences in iPSC-derived endothelial cell (iPSC-EC) characteristics and functionality between healthy donors and high-risk CAD patients.

Methods

IPSC from participants with similar lifestyle but different disease status (healthy >65 y/o, n=5, acute coronary syndrome (ACS) <65y/o, n=6) were differentiated into iPSC-EC. Cells were exposed to inflammatory stimulation with tumour necrosis factor alpha (TNF-a) followed by bulk RNA-seq. Monocyte (THP-1) recruitment was assessed under protective and atherogenic flow conditions. Mitotic age was calculated based on DNA-methylation via Hannum estimate (1) for each donor at the iPSC and iPSC-EC (passage 4) stage.

Results

ACS-iPSC-EC had significantly higher upregulation of E-selectin upon TNF-a stimulation on mRNA level (ACS: 532.1-fold±48.7 vs healthy: 322.3-fold±55.7 with p=0.02). Similarly, ICAM1 protein upregulation was higher in ACS-iPSC-EC compared to healthy iPSC-EC as determined by flow cytometry (ACS: 1.4-fold±0.01 vs healthy: 1.1-fold±0.0007; p<0.001). ACS-iPSC-EC recruited significantly more THP-1 per view field under protective (high shear stress, laminar) flow conditions (ACS: 78.4±20.7 vs healthy: 33.25±12.3 with p=0.04) compared to healthy iPSC-EC. While both groups recruited significantly more THP-1 under atherogenic than protective conditions (ACS: 302±38.9 with p=0.0055 vs healthy: 340±70.4 with p=0.0005), there was no difference between the donor groups (p=0.43). Analysis of bulk RNA-seq data showed significant differences in TNF-a-induced transcriptome changes. Gene set enrichment analysis identified differences in signalling pathways related to leukocyte and lymphocyte-mediated immunity, adaptive immune response, cytokine activity, and many more as shown in Figure 1 (p.adj ≤1e-10). IPSC of both groups had a negative calculated mitotic age (in years) which significantly increased after endothelial differentiation and four population doublings (ACS-iPSC: −14.1±0.7 vs ACS-EC: −0.1±1.1, p<0.0001 and healthy-iPSC: −13.7±0.8 vs healthy-EC: 2.5±1.5, p=0.0001).

Conclusion

The higher rate of basal THP-1 recruitment and upregulation of adhesion molecules on mRNA and protein level and the distinct transcriptome changes suggest intrinsic differences between patient and healthy iPSC-EC both in the basal state and in inflammatory response. Furthermore, this demonstrates iPSC as a viable in vitro model also for polygenetic diseases such as CAD.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): German Cardiac Society, Research Scholarship

Galectin-3 as a possible marker for increased thrombogenicity in COVID-19

Background

Galectin-3 is a β-galactoside-binding lectin that has been described to be overexpressed in inflammation, atherosclerosis, and in myocardial fibrosis. In COVID-19, galectin-3 has been proposed as an important regulator of the inflammatory response and fibrosis processes. The role of galectin-3 as a platelet activator and thrombosis enhancer has been also recently described. However, the role of galectin-3 in the thrombotic risk in COVID-19 hasn't been studied extensively.

Methods

Patients with moderate to severe COVID-19 were included in the study. Hospitalized patients with acute respiratory diseases without COVID-19 were examined as controls. We compared the levels of galectin-3, soluble ST2, tissue factor and tissue factor activity (TFa) as well as several other markers of increased thrombogenicity in both groups. The correlations between galectin-3 and coagulation as well as inflammation markers were assessed. The SOFA score was used as a marker for the clinical outcome.

Results

93 patients were included into the study of which 56 were SARS-CoV-2 positive (COV+) and 37 were SARS-CoV-2 negative controls (COV−). Galectin-3 levels were higher in the COV+ group (median 7.10 ng/ml [IQR 4.61–9.81] vs. 5.47 ng/ml [3.63–6.66] p=0.016) as well as the TFa (median 334.48 pM [115.19–632.58] vs. 134.02 pM [86.92–206.66]) and the ST2 levels (median 5.49 ng/ml [2.40–9.28] vs. 2.19 ng/ml [0.66–3.91] p<0.001). We also observed a positive correlation between galectin-3 and IL-6 (r=0.559, p<0.001), ST2 (r=0.332, p=0.005), SOFA score (r=0.441, p=0.003), von Willebrand factor (r=0.401, p<0.001), plasminogen (r=0.361, p=0.001), antithrombin (r=0.453, p<0.001), and D-dimer (r=0.377, p=0.001).

Conclusion

In patients with acute respiratory diseases, especially with COVID-19, galectin-3 is a marker for increased hypercoagulability and worse clinical outcome. Galactin-3 might be a useful therapeutic target for patients with COVID-19.

Funding Acknowledgement

Type of funding sources: None.

NK cells are associated with immunometabolic response to a single exercise exertion in heart failure patients

Background

Increased systemic inflammation and metabolic dysfunction are observed in heart failure with reduced ejection fraction (HFrEF). On the other hand, cardiorespiratory exercise testing (CPET) exerts a physical challenge and initiates the activation of the immune system, including acute release of natural killer (NK) cells into the circulation, and several metabolic pathways.

Aim

To characterize the inflammatory and metabolic alterations of HFrEF patients in response to an acute exercise challenge, and after 2 hours of recovery.

Methods

Participants with HFrEF (n=16), age and sex matched controls (CON, n=13) were investigated at baseline, immediately after and 2 hours after CPET. Clinical and physiological parameters, leukocyte profile, plasma cytokines and metabolites were assessed along with inflammatory and metabolic parameters at all three time points. NK cell counts and morphological/activation parameters in different contexts were examined. Further, the time-dependent coordination of NK cell numbers post-exercise with tryptophan metabolism and plasma triglycerides were assessed. NK cells were isolated from blood of healthy donors for ex vivo proof-of-principle experiments, including phenotype polarization and NK cell specific tryptophan metabolism.

Results

Cardiovascular risk profiles as well as leukocyte, cytokine and metabolic parameters at baseline were similar in CON and HFrEF. Immediately after CPET, lactate, and NK T cell blood counts were significantly increased in both groups. In HFrEF but not CON, platelet aggregates with NK cells, CD8+ cytotoxic T cells and “classical” CD14++CD16-monocytes, phosphatidylcholines and triglycerides were increased. After 2h of recovery, almost all altered parameters returned to baseline in CON. In contrast, blood counts and morphological markers of inflammatory effector cell types, including CD8+ T cells and neutrophils remained elevated in HFrEF. NK cells remained elevated after the recovery period and correlated with levels of various triglyceride species in the HFrEF patients. Tryptophan levels in plasma were reduced by acute exercise and the kynurenine to tryptophan ratio was increased and correlated with increase in NK and NK-T cell counts, as well as IL-12 plasma levels. Treatment with IL-12 led to increased synthesis of kynurenine from tryptophan, expression of indoleamine 2,3-dioxygenase and abundance of regulatory CD56bri NK cell phenotypes ex vivo. Secretome of untreated NK cells impaired cellular respiration, increased glycolysis/oxidation ratio in skeletal muscle cells, and increased the release of triglycerides from hepatocarcinoma cells.

Conclusion

CPET induced a complex acute immunometabolic response, whose restitution to baseline levels differed between HFrEF and healthy controls. Exercise-induced changes in NK cell metabolism and phenotype shift might modulate cellular respiration in myocytes and release of triglycerides by hepatocytes in HFrEF and in CON.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): DZHK (German Centre for Cardiovascular Research)

Prognostic implications of cholesterol chrystals at ACS causing culprit lesions, insights from the translational OPTICO-ACS study program

Aims

Cholesterol chrystals (CC) represent a feature of advanced plaque remodeling. Optical coherence tomography (OCT) allows for detailed morphological assessment of the culprit lesion, including the presence of CCs, in vivo. Since CCs have been identified as prognostically relevant plaque feature in coronary artery disease (CAD), the present analysis aims to further characterize their impact on adverse cardiovascular outcome in a large cohort of patients, presenting with acute coronary syndrome (ACS).

Methods

Within the translational OPTICO-ACS study program, 371 consecutive ACS-patients were included into the final analysis. OCT-characteristics, including the presence of CCs, were assessed by a standardized CoreLab analysis following universal consensus standards for OCT-derived plaque features. All patients were followed up for 12 months after the index event and major adverse cardiac events (MACE) consisting of death, myocardial infarction, target vessel revascularization plus re-hospitalization due to unstable or progressive angina pectoris were documented.

Results

215 patients (58.1%) presented with cholesterol chrystals (CCs) at the culprit lesion. Plaque rupture (RFC-ACS) represented the primary ACS-causing pathophysiology (75.3%) in those patients. Further, the presence of CCs was associated with other high-risk features within the culprit lesion, i.e. the presence of thin cap fibroatheroma (77.7% vs. 63.2%; p&lt;0.05), plaque calcification (80.5% vs. 67.1; p&lt;0.01) and microchannels (80.1% vs. 70.1; p&lt;0.05) as well as an increased area stenosis (0.77 vs. 0.73 mm2; p&lt;0.01) and a greater maximum lipid arc (282.8 vs. 242.6°; p&lt;0.01) as compared to culprit lesions free of CCs. Of note, there was a strong association among the occurrence of macrophages within the plaque and cholesterol crystals. Finally, and most importantly MACE during 12 months follow-up, consisting of cardiac death, myocardial infarction, target vessel revascularization and re-hospitalization due to progressive or unstable angina pectoris, occurred with nearly twice the frequency in CC-patients (20.3% vs. 10.6%; p&lt;0.01) as compared to patients without CCs at the culprit site.

Conclusion

The present analysis introduces cholesterol chrystals as a novel prognostically relevant high-risk plaque feature allowing individual risk stratification for patients after ACS.

Funding Acknowledgement

Type of funding sources: None.

Immune-metabolome response to an acute exercise exertion reveals dysfunctional metabolic recovery in heart failure

Funding Acknowledgements

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

Background

Patients with heart failure with reduced ejection fraction (HFrEF) have an increased inflammatory load and impaired cardiac oxidative lipid phosphorylation. Early dysregulations of pathophysiological alterations may not be detectable if patients are assessed under resting conditions.

Purpose

We exposed HFrEF patients to a physical exertion challenge by cardiopulmonary exercise testing (CPET) and determined inflammatory and metabolic parameters before, during and 2 hours after the test.

Methods

A symptom-limited CPET was performed in participants with HFrEF (n = 16) and age and sex matched controls (CON, n = 13). In addition to clinical and physiological parameters, we assessed blood counts of leukocyte subtypes, their morphology, aggregation with platelets and microvesicle release, as well as plasma cytokines and metabolites at baseline (T1), immediately after CPET (T2), and after 2 hours of rest (T3). Inflammatory and metabolic parameters were measured using the ThermoFischer ProcartaPlex Human Inflammation-Panel and Biocrates MxP® Quant 500 kit, respectively. Non-parametric tests were chosen and all multiple tests were adjusted by the Benjamini-Hochberg method.

Results

Cardiovascular risk profile of HFrEF and CON was similar. In agreement with the definition for HFrEF, these patients had a lower EF and a greater left ventricular enddiastolic diameter compared to CON. There were no differences between groups for leukocyte, cytokine or metabolic parameters at T1. Immediately after CPET, 20 parameters were significantly increased in both groups, including an increase of lactate, natural killer (NK) and NK T cell blood counts. In addition, 131 inflammatory and metabolic parameters were upregulated only in HFrEF, as compared to only 17 in CON. In HFrEF-platelet aggregates with NK cells, CD8+ cytotoxic T cells and "classical" CD14++CD16-monocytes, 58 different phosphatidylcholines and 21 triglycerides were upregulated immediately after exercise. At T3 almost all altered parameters returned to baseline in CON while in HFrEF blood counts and morphological markers of inflammatory effector cell types, including NK cells, CD8+ T cells and neutrophils, as well as genomic nuclear DNA, an indicator of cell death, remained elevated. Moreover, several triglycerides did not return to baseline in HFrEF after a 2-hour resting period. In these patients, but not in CON, the different lipids (i.e. phosphatidylcholine, triglycerides) strongly correlated with pro-inflammatory cytokines and NK cells.

Conclusion

Our data support the concept of impaired fatty acid utilization and inflammation-mediated metabolic dysregulation in HFrEF. However, the correlations between metabolic and inflammatory parameters were not detected at baseline in comparison to a control group with similar cardiovascular risk profile. Therefore, investigating patients in response to a physical or metabolic challenge might reveal early pathological changes.

TLR2 signalling orchestrates neutrophil activation in acute coronary syndrome with intact fibrous cap – results from the OPTICO-ACS study

Background

Neutrophil granulocytes are key players of the innate immunity, participating in the initiation and progression of atherosclerosis. However, the exact mechanisms of neutrophil activation after acute coronary syndrome (ACS) are poorly understood, especially in the context of the two predominant ACS-causing pathophysiologies - ACS with intact fibrous cap (IFC-ACS) and ACS with ruptured fibrous cap (RFC-ACS). Therefore, the current study focuses on immunophenotyping and ex-vivo functional characterization of neutrophils with regard to the molecular differences between IFC-ACS and RFC-ACS.

Methods

Using high-resolution optical coherence tomography (OCT) of the ACS-causing culprit lesion and re-evaluation by a second OCT-core lab, thirty-two IFC-ACS-patients were matched to thirty-two RFC-ACS-patients by gender, age and diabetes. Local and systemic blood samples were obtained from the site of the ACS-causing culprit lesion (LOC) and from the arterial sheath (SYS), respectively. Neutrophil abundance and surface marker expression were quantified by flow cytometry. Fresh neutrophils were isolated for functional analysis and ex-vivo assessment of cell-toxicity in a co-culture with human aortic endothelial cells (HAECs). Neutrophil secretion of active MMP9 was evaluated by fluorescence-based zymography in supernatants of isolated neutrophils and in patients' plasma samples.

Results

Neutrophils of patients with IFC-ACS show significantly higher expression of the toll-like receptor 2 (TLR2) in comparison to RFC-ACS-derived neutrophils (LOC: 1991±492.8 vs. 1615±440.2; p=0.01; SYS: 2062±464.4 vs. 1670±525.1; p=0.0056). Ex-vivo TLR2-stimulation of local neutrophils in patients with IFC-ACS led to increased toxicity of their secretome and aggravated endothelial cell death in co-culture, as compared to neutrophils from RFC-ACS patients (+59% dead HAECs, IFC-LOC vs. RFC-LOC; p=0.0078). Furthermore, TLR2-stimulation using Pam3CSK4 triggered higher activity rates of MMP9 exclusively in local neutrophils of IFC-ACS-patients (+38.9%±6.1% in IFC-LOC vs. RFC-LOC; p=0.0154). This effect was reversed in IFC-ACS-derived neutrophils being pre-treated with an anti-TLR2 neutralizing antibody (−58.4% ±5.2%, IFC-LOC-anti-TLR2 vs. IFC-LOC-vehicle; p=0.0069). Additionally, MMP9 activity was higher in plasma obtained from the culprit site of IFC-ACS patients (74.1 U/ml ±4.1 vs. 70.0 U/ml ±5.1, IFC-LOC vs. RFC-LOC; p=0.01).

Conclusion

The current study demonstrates novel TLR2-dependant neutrophil activation patterns at the coronary culprit lesion of IFC-ACS, leading to higher endothelial cell toxicity and MMP9 activity. Further studies need to assess whether a temporary blockade of TLR2 activation could be a possible therapeutic target in the era of personalized medicine.

Funding Acknowledgement

Type of funding source: Public Institution(s). Main funding source(s): Berlin Institute of Health (BIH), German Center for Cardiovascular Research

Novel effects of Foxo3a on immune system and cardiac remodeling after myocardial infarction

Background

Fibroblast/myofibroblast transdifferentiation following acute cardiac injury (MI) is a major mechanism of scar formation and adverse remodeling regulated by TGFβ/SMAD3 signaling. Myofibroblasts represent phenotypically modulated cells characterized by α-smooth muscle actin (α-SMA) and constitute the main source of extracellular matrix proteins such as collagen type I in the healing infarct wound. Moreover, the recruitment of a specific monocyte/macrophages subset (Ly6Chigh and Ly6Clow) control the healing process in the infarcted wound. The forkhead transcription factor FOXO3a has recently been shown to inhibit cardiac hypertrophy by different stressors and is involved in the immune response following injury.

Purpose

We hypothesized that FOXO3a, a key regulator of cell differentiation, cell cycle and size as well as the stress response, might inhibit matricellular remodeling following myocardial infarction by regulating transdifferentiation of fibroblasts into myofibroblasts. Moreover, we hypothesized that Foxo3a−/− mice favor the recruitment of monocytes of the type Ly6Clow leading to an anti-inflammatory profile and thus the remodeling after injury.

Methods

Acute myocardial infarction was induced in FOXO3−/− and WT mice (FVB background) by permanent LAD ligation. The myocardial infarction size was determined via ECHO. Myofibroblast trans-differentiation and fibrosis markers were analyzed by QT-PCR and protein analysis. The differentiation of macrophages studied via FACS. IP/IF and Western blotting were used to test for a direct interaction between FOXO3a and SMAD3 in vitro.

Results

FOXO3a−/− mice showed significantly higher survival rates compared to WT littermates. Myocardial inflammation (Mac-1, LFA, CD3, CD45), injury markers such as Troponin T were similar in both groups on day 4 post-MI. Myocardial expression of alpha smooth muscle actin (ASMA) and Collagen1A1 (Col1A1), as well as numbers of cardiac CD11b+/F4–80+/Ly6clow macrophages was significantly enhanced in FOXO3a−/− mice 15 days post infarction. Moreover, Foxo3a−/− mice showed larger fibrotic areas following MI. Mechanistically, immunoprecipitation showed direct interaction of FOXO3a with SMAD3a that was enhanced following activation of the transcription factor leading to diminished SMAD3 downstream gene expression.

Conclusion

Our results indicate that FOXO3a acts as a direct inhibitor of TGF-β regulated myofibroblast differentiation and matrix remodeling via FOXO3a-SMAD3 interaction following MI. Moreover, a Foxo3a deficiency might lead to the recruitment of monocytes type Ly6Clow leading to an anti-inflammatory profile in the infarct wound. Therefore, FOXO3a collectively regulates cardiac hypertrophy and fibrosis/scar formation following MI. Thus, targeting the FOXO3a-SMAD3 signaling axis might be of future therapeutic interest.

Funding Acknowledgement

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

Inter-individual differences in the response to an exercise training intervention in patients with metabolic syndrome

Background

Regular physical exercise and standardized exercise training (ET) programmes positively affect a number of metabolic and cardiovascular risk factors. Yet, response to ET varies between patients and between individual risk parameters. We investigated inter-individual responses regarding blood pressure, heart rate, lipids and glucose metabolism, as well as physical fitness to a 16-weeks supervised exercise training protocol in patients with metabolic syndrome (MetS).

Methods

29 MetS patients (20M/9F, age 52–70 y, BMI 24.9–38.2 kg/m2) exercised for 16 weeks in a supervised setting with varying volume and intensity. At baseline and at completion of the programme, blood pressure, heart rate, plasma lipids, glucose and insulin levels, as well as physical fitness were assessed, as were quantitative and morphological leukocyte parameters, cytokines and 86 metabolically relevant plasma proteins. Associations between individual risk parameters, leukocyte profile and plasma proteins were explored by recursive partitioning and network analysis. T-distributed stochastic neighbor embedding and hierarchical clustering were used for clustering based on cardiometabolic target parameters at 16 weeks.

Results

In the whole cohort, VO2peak increased and plasma counts of total leukocytes, neutrophils, monocytes (classical and intermediate), NK cells and effector and regulatory CD4+ lymphocytes, as well as circulating endothelial microvesicles were reduced at the end of the ET programme versus baseline. Plasma levels of carboxylesterase 1 decreased and soluble interleukin-7 receptor increased. Based on patient's cardio-metabolic parameters, three clusters were identified: cluster 1 had lower values of triglycerides, total and LDL cholesterol, cluster 2 had higher levels of triglycerides and cluster 3 had a greater heart rate recovery and lower insulin levels, but higher total and LDL cholesterol levels at follow-up. In cluster 1, absolute and relative NK cell counts were decreased and no morphological activation was observed. In cluster 2, reduced relative counts of NK-T cells were decreased, but their size was increased. In cluster 3, size of most effector leukocyte subtypes (CD8+, CD4+ Teff, NK-T, neutrophils) was increased at follow-up versus baseline. Network analysis suggested four distinct networks of (1) triglycerides, (2) VO2peak, (3) diastolic BP and (4) a cluster containing total and LDL cholesterol, insulin and HR recovery, each associated with partly distinct sets of plasma proteins and leukocyte parameters.

Conclusion

Despite improved physical fitness in all patients participating in the 16 weeks ET programme, inter-individual differences regarding cardio-metabolic target parameters and leukocyte activation was evident. Identification of specific leukocyte responses and of plasma protein “fingerprints” might help to optimize patient-specific prevention programmes, integrating medication and lifestyle optimization.

Funding Acknowledgement

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

P6394Neutrophil activation patterns in acute coronary syndrome with intact fibrous cap - results from the OPTICO-ACS study

Background

In up to one third of all cases, acute coronary syndrome occurs without signs of plaque rupture. Instead endothelial cell erosion is considered to be the hallmark of acute coronary syndrome with intact fibrous cap (IFC-ACS), with matrix metalloproteinase 9 (MMP9) directly linked to this pathology. The main source of MMP9 immediately after ACS are the neutrophil granulocytes. Therefore, their molecular activation patterns and subsequent MMP9 production are the objectives of the ongoing, translational OPTICO-ACS-Study, aiming to compare the mechanisms and prognosis of IFC-ACS and ACS with ruptured fibrous cap (RFC-ACS).

Methods

Local and systemic blood samples were simultaneously obtained from the site of the ACS-causing culprit lesion (LOC) using an aspiration catheter and from the systemic circulation (SYS). Using optical coherence tomography (OCT) the ACS-causing culprit lesion was characterized and two patient groups, patients with ACS caused by intact (IFC-ACS) and by ruptured fibrous cap (RFC-ACS) were compared. Each group consists of twenty patients (n=20) matched by age, gender and diabetes. Neutrophil counts and expression of activation markers were immediately quantified by whole-blood flow cytometry. Release of active MMP9 into the plasma was assessed by fluorescence-based zymography. Activation profiles of freshly isolated neutrophils, including MMP9 activity and effect on endothelial cell death, in response to toll-like receptor 2 (TLR2) stimulation was studied.

Results

Local neutrophils of patients with IFC-ACS show significantly higher expression of TLR2 in comparison to RFC-ACS neutrophils (LOC: 1866±382.1 vs. 1498±426.9; IFC-ACS vs. RFC-ACS, p=0.03). MMP9 activity is significant higher (p=0.01) in plasma obtained from the culprit site of IFC-ACS (74.1 U/ml±4.1) compared to those of RFC-ACS patients (70.0 U/ml±5.1) indicating secretion and activation of the enzyme during IFC-ACS. Importantly, in patients with IFC-ACS, TLR2-stimulation using Pam3CSK4 triggers higher activity rates of MMP9 only in neutrophils isolated directly from the culprit site (LOC), but not systemically (+27%±17.2% IFC-LOC vs. IFC-SYS; p=0.003). This effect was not observed in RFC-derived neutrophils. Inhibiting TLR2 by a monoclonal antibody, strongly reduced secretion of activated MMP9 only in the local neutrophils from IFC-ACS-patients (−54.6%±6.5% in IFC-LOC-anti-TLR2 vs. IFC-LOC-vehicle; p=0.008), but not from systemic IFC-neutrophils, nor from RFC-neutrophils. Furthermore, LOC IFC-ACS neutrophils aggravate endothelial cell death upon TLR2-activation in comparison to LOC RFC-ACS neutrophils (58.4±4.96% vs. 20±1.89%, IFC-ACS vs. RFC-ACS; p=0.0023).

Conclusion

We newly describe differential kinetics of MMP9 release by neutrophils in ACS patients with IFC versus RFC. Our data support a role of a TLR-2 activated and neutrophil-MMP9-mediated mechanism leading to endothelial cell erosion in patients with IFC-ACS.

Acknowledgement/Funding

DZHK (German Centre for Cardiovascular Research); BIH (Berlin Institute of Health)

P4418Temporal analysis of leukocyte extravasation and morphological activation after standard cardiopulmonary exercise testing in patients with heart failure with reduced ejection fraction

Introduction

Long-term exercise training reduces the systemic inflammatory load in patients with cardiovascular diseases. Acutely, however, an exercise challenge can trigger pro-inflammatory responses. The underlying cardiac syndrome might also influence the response of the adaptive and innate immune system to an acute exercise challenge.

Purpose

We compared the acute response to a standardized cardiopulmonary exercise test (CPET) in patients with heart failure with reduced ejection fraction (HFrEF) and age matched controls.

Methods

Patients with HFrEF (n=8; left ventricular ejection fraction [LVEF] ≤40%) and controls (n=9, LVEF ≥50%) participated in a CPET. Blood samples were taken before, immediately after and 2 hours after the test. Quantitative and morphological changes in leukocyte subpopulations, and formation of leukocyte-platelet aggregates were assessed in fresh blood samples by flow cytometry. Results are given as median and inter-quartile range (IQR).

Results

HFrEF (mean LVEF: 34%) and controls (mean LVEF: 57%) were 59 (range: 41 to 80) and 57 (range: 50 to 65) years old, respectively. In both groups acute exercise increased total leukocytes per mL of blood (control: 1.37-fold [IQR: 1.16 to 1.49]; HFrEF: 1.24-fold [IQR: 1.20 to 1.32]), relative abundance of circulating NK cells (controls: 2.11-fold [IQR: 1.30 to 3.13]; HFrEF: 1.67-fold [IQR: 1.56 to 1.71] and NK-T cells (control: 1.69-fold [IQR: 1.52 to 3.60]; HFrEF: 1.62-fold [IQR: 1.60 to 2.53]). Contrarily, only in HFrEF patients CD4+ (control: 1.15-fold [IQR: 0.84 to 1.54]; HFrEF: 1.45-fold [IQR: 1.10 to 1.98]) and CD8+ T cells (control: 1.33-fold [IQR: 1.01 to 1.68]; HFrEF: 1.70-fold [IQR: 1.25 to 2.15]) were augmented. Circulating monocyte and neutrophil numbers did not change in response to CPET. Aggregation of thrombocytes with monocytes (control: 0.86-fold [IQR: 0.78 to 1.49]; HFrEF: 1.59-fold [IQR: 1.05 to 7.30-fold]), T-lymphocytes (control: 1.27-fold [IQR: 1.05 to 1.68]; HFrEF: 1.49-fold [IQR: 1.03 to 2.64]) and neutrophils (control: 1.08-fold [IQR: 0.87 to 1.25]; HFrEF: 2.13-fold [IQR: 1.62 to 2.19]) increased 2 hour post-exercise in HFrEF patients, but not in controls.

Conclusion

Patients with HFrEF show a differential leukocyte response to an acute exercise challenge, with an increase in T-lymphocyte abundance, a degranulation response in the intermediate monocyte subpopulation and an increased formation of neutrophil-platelet-aggregates compared to control subjects. Our data suggest differences in release and organ-homing of innate versus adaptive immune cells, thus underlining the importance of inter-organ communication in the acute adaption to physical exertion in HFrEF.

Nitropravastatin stimulates reparative neovascularisation and improves recovery from limb Ischaemia in type-1 diabetic mice

BACKGROUND AND PURPOSE

Mature endothelial cells and their progenitors are dysfunctional in diabetes, resulting in deficient neovascularisation following arterial occlusion. This study aimed to evaluate the therapeutic activity of a nitric oxide (NO) releasing statin in the setting of experimental diabetes and peripheral ischaemia.

EXPERIMENTAL APPROACH

The effects of NCX 6550, an NO-releasing pravastatin derivative, on angiogenesis in ischaemic limbs was studied in normoglycaemic mice or mice made diabetic by treatment with streptozotocin (STZ). Control mice received an equimolar dosage of the parent statin compound, pravastatin. The therapeutic action of NCX 6550 was also tested in mice lacking the gene for endothelial nitric oxide synthase (eNOS).

KEY RESULTS

In normoglycaemic or STZ-diabetic CD1 mice, only NCX 6550 stimulated skeletal muscle revascularisation. In addition, NCX 6550 induced greater improvement in limb reperfusion and salvage, than pravastatin. The number of circulating endothelial progenitor cells was decreased in STZ-diabetic mice, this defect being prevented by NCX 6550 and, to a lesser extent by pravastatin. In vitro, high glucose concentrations reduced the migratory capacity of endothelial progenitor EPCs, which was partly reversed by preincubation with pravastatin and completely reversed by NCX 6550. The postischaemic recovery of eNOS knockout mice was severely impaired as a consequence of depressed angiogenesis and this recovery was improved by treatment with NCX 6550, but not with pravastatin.

CONCLUSIONS AND IMPLICATIONS

These findings indicate that incorporation of a bioactive NO moiety improves the therapeutic profile of statins for the treatment of peripheral vascular disease.