Proteogenomic integration reveals CXCL10 as a potentially downstream causal mediator for IL-6 signaling on atherosclerosis

Background

Genetic and experimental studies support a causal involvement of interleukin-6 (IL-6) signaling in atheroprogression. While trials targeting IL-6 signaling are underway, any benefits must be balanced against an impaired host immune response. Dissecting the mechanisms that mediate the effects of IL-6 signaling on atherosclerosis could offer insights about novel drug targets with more specific effects.

Methods

Leveraging data from 522,681 individuals, we constructed a genetic instrument of 26 variants in the gene encoding the IL-6 receptor (IL-6R) that proxied for pharmacological IL-6R inhibition. Using Mendelian randomization (MR), we assessed its effects on 3,281 plasma proteins quantified with an aptamer-based assay in the INTERVAL cohort (n=3,301). Using mediation MR, we explored proteomic mediators of the effects of genetically proxied IL-6 signaling on coronary artery disease (CAD), large artery atherosclerotic stroke (LAAS), and peripheral artery disease (PAD). For significant mediators, we tested associations of their circulating levels with incident cardiovascular events in a population-based study (n=1,704) and explored the histological, transcriptomic, and cellular phenotypes correlated with their expression levels in samples from human atherosclerotic lesions.

Results

We found significant effects of genetically proxied IL-6 signaling on 70 circulating proteins involved in cytokine production/regulation and immune cell recruitment/differentiation, which correlated with the proteomic effects of pharmacological IL-6R inhibition in a clinical trial. Among the 70 significant proteins, genetically proxied circulating levels of CXCL10 were associated with risk of CAD, LAAS, and PAD with up to 67% of the effects of genetically downregulated IL-6 signaling on these endpoints mediated by decreases in CXCL10. Higher midlife circulating CXCL10 levels were associated with a larger number of cardiovascular events over 20 years, whereas higher CXCL10 expression in human atherosclerotic lesions correlated with a larger lipid core and a transcriptomic profile reflecting immune cell infiltration, adaptive immune system activation, and cytokine signaling.

Conclusions

Integrating multiomics data, we found a proteomic signature of IL-6 signaling activation and mediators of its effects on cardiovascular disease. Our analyses suggest the interferon-γ-inducible chemokine CXCL10 to be a potentially causal mediator for atherosclerosis in three vascular compartments and as such could serve as a promising drug target for atheroprotection.

41 Circulating levels and prognostic cut-offs of sST2, high-sensitivity troponin T, and NT-proBNP in women vs. men with chronic heart failure

Aims

Limited evidence exists on sex-related differences in clinical value of biomarkers in chronic heart failure (HF). We aimed to define plasma levels, determinants, and optimal prognostic cut-offs of soluble suppression of tumourigenesis-2 (sST2), high-sensitivity troponin T (hs-TnT), and N-terminal pro-B-type natriuretic peptide (NT-proBNP) in female and male chronic HF patients.

Methods and results

Individual data of patients from the BIOS (Biomarkers In Heart Failure Outpatient Study) Consortium with sST2, hs-TnT, and NT-proBNP measured were analysed. The primary endpoint was a composite of 1-year cardiovascular death and HF hospitalization. The secondary endpoints were 5-year cardiovascular and all-cause death. The cohort included 4540 patients (age: 67 ± 12 years, LVEF 33 ± 13%, 1111 women, 25%). Women showed lower sST2 (24 vs. 27 ng/ml, P < 0.001) and hs-TnT level (15 vs. 20 ng/l, P < 0.001), and similar concentrations of NT-proBNP (1540 vs. 1505 ng/l, P = 0.408). Although the three biomarkers were confirmed as independent predictors of outcome in both sexes, the optimal prognostic cut-off was lower in women for sST2 (28 vs. 31 ng/ml) and hs-TnT (22 vs. 25 ng/l), while NT-proBNP cut-off was higher in women (2339 ng/l vs. 2145 ng/l). The use of sex-specific cut-offs improved risk prediction compared to the use of previously standardized prognostic cut-offs (Figure).

Conclusions

In patients with chronic HF, levels of sST2 and hs-TnT, but not of NT-proBNP are lower in women. Lower sST2 and hs-TnT and higher NT-proBNP cut-offs for risk stratification could be used in women.

Cardiac function is normal in most patients recovered from COVID-19

Background

There are conflicting results regarding impaired cardiac function in patients that have recovered from COVID-19. Cardiovascular magnetic resonance (CMR) studies have revealed a very high frequency of cardiac involvement (78%) and ongoing myocardial inflammation (60%) in patients recently recovered from COVID-19. Findings are advocating further investigation of the long-term myocardial consequences of COVID-19 disease.

Purpose

We aimed to investigate left ventricular (LV) and right ventricular (RV) function by a comprehensive echocardiographic study in patients recovered from COVID-19 infection 3 months after admission to hospital.

Methods

All patients (n=92) had been hospitalized for COVID-19 and were examined with echocardiography three months after hospitalization. They were 59±13 years, and 43% were women. LV function was assessed by ejection fraction (EF) and global longitudinal strain (GLS) and RV function was measured by fractional area change (FAC), tricuspid annular plane systolic excursion (TAPSE) and RV GLS free wall. Tricuspid regurgitation pressure gradient was measured to estimate pulmonary artery pressure.

Results

LV EF was 63±6% and LV GLS was −18.6±2.2%. All patients had normal EF >53%, but 10 showed signs of subtle impaired LV function by LV GLS (≥ −16%). Only two of these did not have hypertension, LV hypertrophy, diabetes or other preexisting diagnosis of heart disease explaining subtle LV dysfunction. All had normal RV FAC (48±7%) and TAPSE (2.3±0.3 cm). We found modestly impaired RV longitudinal function (RV GLS free wall >−25%) in 30% patients, but none had RV GLS worse than −20%. One-third of all patients with reduced RV GLS had signs of elevated pulmonary arterial pressures, which might impact the assessment of RV function.

Conclusions

Traditional echocardiographic parameters showed normal function in all hospitalized COVID-19 patients three months after hospital admittance. Approximately one-third had subtle ventricular dysfunction detected by sensitive echocardiographic methods, but these findings could mostly be explained by systemic or pulmonary hypertension. We cannot, however, exclude that a slight reduction in cardiac function in a minority of our patients was caused by the COVID-19 infection.

Funding Acknowledgement

Type of funding sources: Public hospital(s). Main funding source(s): National Clinical Therapy Research in the Specialist Health Services, Norway

Elevated markers of gut leakage and inflammasome activation in COVID-19 patients with cardiac involvement

BACKGROUND

A high proportion of COVID-19 patients have cardiac involvement, even those without known cardiac disease. Downregulation of angiotensin converting enzyme 2 (ACE2), a receptor for SARS-CoV-2 and the renin-angiotensin system, as well as inflammatory mechanisms have been suggested to play a role. ACE2 is abundant in the gut and associated with gut microbiota composition. We hypothesized that gut leakage of microbial products, and subsequent inflammasome activation could contribute to cardiac involvement in COVID-19 patients.

METHODS

Plasma levels of a gut leakage marker (LPS-binding protein, LBP), a marker of enterocyte damage (intestinal fatty acid binding protein, IFABP), a gut homing marker (CCL25, ligand for chemokine receptor CCR9) and markers of inflammasome activation (IL-1β, IL-18 and their regulatory proteins) were measured at three time points (day 1, 3-5 and 7-10) in 39 hospitalized COVID-19 patients and related to cardiac involvement.

RESULTS

Compared to controls, COVID-19 patients had elevated plasma levels of LBP and CCL25 but not IFABP, suggesting impaired gut barrier function and accentuated gut homing of T cells without excessive enterocyte damage. Levels of LBP were twice as high at baseline in patients with elevated cardiac markers compared with those without and remained elevated during hospitalization. Also, markers of inflammasome activation were moderately elevated in patients with cardiac involvement. LBP was associated with higher NT-pro-BNP levels, whereas IL-18, IL-18BP and IL-1Ra were associated with higher troponin levels.

CONCLUSION

Patients with cardiac involvement had elevated markers of gut leakage and inflammasome activation, suggestive of a potential gut-heart axis in COVID-19.

Angiopoietin-2 is a long-term predictor of all-cause mortality, cardiac death and sudden cardiac death in chest-pain patients with suspected acute coronary syndrome

Background

Angiopoietin-2 (ANGPT2) is an important regulator of angiogenesis. Higher levels of ANGPT2 have been found to be associated with an adverse cardiovascular risk factor profile potentially reflecting maladaptive vascular remodelling including atherosclerotic plaque destabilization.

Purpose

To evaluate the prognostic utility of ANGPT2 added to conventional clinical risk factors for coronary heart disease, including B-type natriuretic peptide (BNP), troponin T (TnT) and C-reactive protein (CRP), in patients with suspected acute coronary syndrome (ACS).

Methods

871 chest-pain patients with clinically suspected ACS from South-Western Norway and 982 patients from Northern Argentina were consecutively included in a prospective transatlantic cohort study. We measured plasma-concentrations of ANGPT2 in admission-samples from 1815 patients by enzyme immunoassay. Univariable- and multivariable Cox proportional-hazards models, applying both loge-transformed continuous values and quartiles (Q1–4), were fitted for the analysis of all-cause mortality, cardiac death and sudden cardiac death (SCD) within 24-month follow-up. Of the patients with suspected ACS, 838 patients had TnT release above the detection-limit of 0.01 ng/mL. We performed subgroup analysis for all-cause mortality in patients with and without TnT release.

Results

Median age in the total population was 66.0 (Q1-Q3; 55.0–76.8) years and 60.4% were males. At 24-month follow-up, 254 patients (14%) had died, of which 150 (8.3%) suffered cardiac death and 76 (4.2%) SCD. ANGPT2 levels were significantly higher in patients who died compared to long-term survivors [3.87 (2.40–7.54) ng/mL versus 2.11 (1.48–3.22) ng/mL (median, 25 and 75% percentiles), p<0.001]. In multivariable analysis, ANGPT2 concentrations in the highest quartile (Q4) as compared to the lowest (Q1) were significantly associated with all-cause mortality [Hazard Ratio (HR) 1.96 (95% confidence interval (CI); 1.12–3.42), p=0.018) and cardiac death [HR 2.23 (95% CI; 1.01–4.92), p=0.047] at 24-month follow-up. For SCD, ANGPT2 concentrations in both Q3 [HR 3.59 (95% CI; 1.05–12.3), p=0.041] and Q4 [HR 3.81 (95% CI; 1.12–12.9), p=0.032] as compared to Q1 were significantly related to outcome. These results were confirmed using loge-transformed continuous values of ANGPT2. ANGPT2 was also an independent predictor of all-cause mortality in both patients with and without TnT release. For patients with TnT >0.01 ng/mL, HR for ANGPT2 in Q4 as compared to Q1 was 2.77 (95% CI: 1.41–5.44), p=0.003. For patients with TnT ≤0.01, HR for ANGPT2-Q4 was 2.67 (95% CI: 1.08–6.62), p=0.034.

Conclusion

High levels of ANGPT2 were found to independently predict all-cause mortality, cardiac death and sudden cardiac death in chest-pain patients with suspected ACS, irrespective of clinical demographics, troponin-release, CRP and BNP.

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): Western Norway Regional Health Authority

Angiopoietin-like 4 protein is a long-term predictor of outcome in chest-pain patients with suspected acute coronary syndrome

Introduction

Angiopoietin-like 4 protein (ANGPTL4) has multiple physiological functions including modulation of angiogenesis, vascular permeability and lipid-metabolism. Acting as an inhibitor of lipoprotein lipase, ANGPTL4 has previously been found to be associated with lipid levels and risk of coronary artery disease.

Purpose

To assess the prognostic value of ANGPTL4 for long-term outcome, in addition to conventional clinical risk factors, in chest-pain patients admitted with clinically suspected acute coronary syndrome (ACS).

Methods

1853 patients from Norway and Northern-Argentina were consecutively included in this prospective 2-center cohort study. ANGPTL4 concentrations were measured in 1829 admission-samples by enzyme immunoassay. Data were pooled for analysis. Multivariable Cox proportional-hazards models were fitted for the analysis of all-cause mortality, cardiac death and sudden cardiac death (SCD) within 24-months, comparing event rates across ANGPTL4-quartiles (Q1–4). Of patients with suspected ACS, 845 had a troponin T (TnT) value above the detection-limit. Subgroup analysis was performed for all-cause mortality in patients stratified according to TnT release >/≤0.01 ng/mL.

Results

During 24-months follow-up, 254 patients (13.9%) died, of which 150 (8.2%) suffered cardiac death and 76 (4.2%) SCD. Patients who died had significantly higher admission-levels of ANGPTL4 compared to long-term survivors [4.99 (3.54–8.37) ng/mL versus 3.18 (2.14–4.78) ng/mL (median, 25 and 75% percentiles), p<0.001]. A stepwise increase in risk of all-cause death was seen with increasing quartiles of ANGPTL4, Figure 1. For cardiac death, ANGPTL4-levels in Q4 [Hazard Ratio (HR) 2.86 (95% confidence interval (CI); 1.10–7.45), p=0.031] as compared to Q1 were found to be an independent predictor of outcome. Similar results were seen for SCD in adjusted analysis for ANGPTL4-Q4 [HR 7.37 (95% CI: 1.75–31.1), p=0.007] as compared to Q1. In subgroup analysis, ANGPTL4 concentrations in the highest quartile were significantly associated with increased risk of all-cause mortality in patients with TnT-release [HR 2.07 (95% CI: 1.06–4.02), p=0.032], but not in patients without TnT-release.

Conclusion

High admission-levels of ANGPTL4 were found to be an independent long-term predictor of all-cause mortality, cardiac death and SCD in patients with suspected ACS.

Figure 1

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): Western Norway Regional Health Authority

Complement component-7 is a long-term predictor of all-cause mortality in chest-pain patients with suspected acute coronary syndrome

Introduction

The complement cascade is an important component of the innate immune system. Complement activation plays a major role in chronic inflammation and has been associated with atherosclerosis, atherosclerotic plaque destabilization and increased risk of cardiovascular events. Complement component 7 (C7) binds C5bC6 complex being part of the terminal complement complex (TCC/C5b-9).

Purpose

To investigate the prognostic utility of complement C7 for long-term outcome in patients with suspected acute coronary syndrome (ACS).

Methods

Complement C7 plasma-levels were measured by enzyme immunoassay in admission samples from 1823 patients included in a transatlantic prospective cohort study, which consecutively included hospital admitted chest-pain patients with clinically suspected ACS from South-Western Norway and Northern Argentina. Data were pooled for analysis. Univariable- and multivariable Cox proportional-hazards models were fitted for the analysis of all-cause mortality, cardiac death and sudden cardiac death (SCD) within 24 months, applying both quartiles (Q1–4) and loge-transformed continuous values of complement C7.

Results

There were 253 (13.9%) deaths, of which 150 (8.2%) were categorized as cardiac death and 76 (4.2%) as SCD. Complement C7 levels were significantly higher in patients who died as compared to long-term survivors [176.9 (142.1–228.7) μg/mL versus 139.8 (110.6–179.7) μg/mL (median, 25 and 75% percentile), p<0.001], and were significantly associated with 24-month survival [log rank p<0.001 for all-cause mortality and cardiac death, log rank p=0.035 for SCD]. In univariable analysis, patients with complement C7-concentrations in the highest quartiles had significantly increased risk of all-cause mortality (Figure 1), cardiac death [Q4: Hazard Ratio (HR) 4.58 (95% confidence interval (CI): 2.65–7.92), p<0.001, Q3: HR 2.69 (95% CI: 1.51–4.80), p=0.001] and SCD [Q4: HR 2.83 (95% CI: 1.36–5.90), p=0.005, Q3: HR 2.33 (95% CI: 1.10–4.92), p=0.027] compared to patients in the lowest quartile (Q1). After adjusting for conventional clinical risk factors for coronary heart disease, complement C7-concentrations in Q4 [HR 2.09 (95% CI: 1.23–3.57), p=0.007] and Q3 [HR 2.21 (95% CI: 1.29–3.81), p=0.004] remained significantly associated with all-cause mortality, reproduced using loge-transformed continuous values.

Conclusion

High levels of complement C7 were found to independently predict long-term all-cause mortality in chest-pain patients with clinically suspected ACS.

Figure 1

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): Western Norway Regional Health Authority

Profiling of immune-related gene expression in children with familial hypercholesterolaemia

BACKGROUND

Innate and adaptive immune responses are pivotal in atherosclerosis, but their association with early-stage atherosclerosis in humans is incompletely understood. In this regard, untreated children with familial hypercholesterolaemia may serve as a human model to investigate the effect of elevated low-density lipoprotein (LDL)-cholesterol.

OBJECTIVES

We aimed to study the immunological and inflammatory pathways involved in early atherosclerosis by examining mRNA molecules in peripheral blood mononuclear cells (PBMCs) from children with FH.

METHODS

We analysed the level of 587 immune-related mRNA molecules using state-of-the-art Nanostring technology in PBMCs from children with (n = 30) and without (n = 21) FH, and from FH children before and after statin therapy (n = 10).

RESULTS

176 genes (30%) were differentially expressed between the FH and healthy children at P < 0.05. Compared to healthy children, the dysregulated pathways in FH children included the following: T cells (18/19); B cells (5/6); tumour necrosis factor super family (TNFSF) (6/8); cell growth, proliferation and differentiation (5/7); interleukins (5/9); toll-like receptors (2/5); apoptosis (3/7) and antigen presentation (1/7), where the ratio denotes higher expressed genes to total number of genes. Statin therapy reversed expression of thirteen of these mRNAs in FH children.

CONCLUSION

FH children display higher PBMC expression of immune-related genes mapped to several pathways, including T and B cells, and TNFSF than healthy children. Our results suggest that LDL-C plays an important role in modulating expression of different immune-related genes, and novel data on the involvement of these pathways in the early atherosclerosis may represent future therapeutic targets for prevention of atherosclerotic progression.

2232Circulating levels of ST2 are associated with myocardial injury, left ventricular function and future adverse clinical events in patients with ST-elevation myocardial infarction

Background

Soluble ST2, a member of the IL-1 receptor family, seems to be associated with adverse outcome in acute myocardial infarction and heart failure (HF), and is suggested to be involved in left ventricular (LV) remodelling.

Purpose

To elucidate a possible role of ST2 in LV injury, remodelling and prognosis in ST-elevation myocardial infarction (STEMI) patients. The main objectives of the study were to investigate whether circulating ST2 levels were associated with infarct size, LV function, adverse remodeling and clinical outcome in a cohort of patients with STEMI.

Methods

270 patients with clinically stable first-time STEMI treated with primary percutaneous coronary intervention (PCI) were included. Blood samples were drawn before and immediately after the PCI procedure, at day 1 (median 18.3 hours after PCI) and after 4 months. Cardiac magnetic resonance (CMR) was performed in the acute phase and after 4 months. Clinical events and all-cause mortality were registered during 12 months' and 70 months' follow-up, respectively. A composite endpoint was defined as death, MI, unscheduled revascularisation >3 months after the index infarction, rehospitalisation for HF or stroke. Associations between ST2 and CMR parameters and clinical events were evaluated with linear regression and logistic regression, respectively.

Results

There was a significant increase in ST2 levels from the PCI procedure to day 1 with a subsequent decline from day 1 to 4 months in the POSTEMI cohort. Patients with high ST2 levels (>median) at all sampling points during hospitalisation had significantly larger infarct size, lower myocardial salvage, lower LVEF, larger increase in EDV and higher frequency of MVO. After adjustment for relevant clinical variables, peak CRP and peak troponin T, ST2 measured at day 1 remained associated with infarct size (β 2.0 per SD of ST2, p<0.001) and LVEF (β −1.8 per SD of ST2, p=0.02) at 4 months. High levels of ST2 measured at day 1 (>75th percentile) were associated with increased risk of having an adverse clinical event during the first year and with long-term all-cause mortality (Figure). High levels of ST2 measured in a stable phase 4 months after STEMI were also associated with an increased risk of all-cause mortality (Figure).

Figure 1

Conclusions

High levels of ST2 in STEMI patients were associated with large infarct size, impaired recovery of LV function, and adverse clinical outcome in patients with STEMI. ST2 measured 4 months after STEMI remained associated with all-cause mortality.

P826Peri-procedural treatment with high dose Rosuvastatin reduces soluble TNF receptor 1 in patients treated with primary percutaneous coronary intervention for ST elevation myocardial infarction

Background

The extent of cardiac injury in ST elevation myocardial infarction (STEMI) depends on the level of inflammation and subsequent immune cell recruitment. An inflammatory phase that is disproportionately prolonged, of excessive magnitude, or insufficiently suppressed, can lead to sustained tissue damage and improper healing, promoting infarct expansion, adverse remodelling and chamber dilatation. Soluble TNF receptor 1 (sTNFR-1) is believed to mirror systemic pan-inflammatory status more closely than a single cytokine antigenic level. sTNFR-1 levels might give prognostic information, independent from and, at the same time, additive with some well-recognized outcome predictors such as left ventricular ejection fraction.

Purpose

We hypothesised that sTNFR-1 and other inflammatory markers could be modulated by statins.

Methods

Plasma levels of inflammatory markers were measured at baseline, 2 days, 7 days and 2 months in consecutive patients with first time STEMI with single vessel disease. Twenty-five patients (treatment group (TG)) were treated with 80 mg Rosuvastatin daily with first dose before primary percutaneous coronary intervention (PCI) whereas the control group (CG) consisted of 34 patients in whom treatment with 20 mg simvastatin daily were initiated the day after PPCI.

Results

sTNFR1 increased during the first 48 hours following PCI and this increase was larger in the CG compared with the TG (0.22±0.30 ng/mL vs 0.08±0.19 ng/nmL, p=0.025). The difference in increase during one week was only borderline statistically significant (0.21±0.30 ng/mL vs 0.08±0.26 ng/mL, p=0.081). These differences in the kinetics of sTNRF-1 were mirrored by changes in Pentraxin 3 (PTX3) between groups from baseline to 1 week, CG vs TG. (0.28±0.70 μmol/l vs 0.10±0.05 ng/mL, p=0.014) and at 2 months (−0.42±0.56 ng/mL vs 0.08±0.60 μmol/l, p=0.032)

Conclusion

High dose Rosuvastatin therapy initiated peri-procedural during PPCI for STEMI reduces pan inflammation as reflected by sTNFR1 and is associated with a less abrupt fall in PTX3 at 1 week and 2 months supporting recent research suggesting that PTX3 plays a cardiovascular protective effect in cardiovascular disease and healing.

Acknowledgement/Funding

Western Norway Regional Health Authority

Prognostic biomarkers for immunotherapy with ipilimumab in metastatic melanoma

New therapies, including the anti‐cytotoxic T lymphocyte antigen (CTLA)‐4 antibody, ipilimumab, is approved for metastatic melanoma. Prognostic biomarkers need to be identified, because the treatment has serious side effects. Serum samples were obtained before and during treatment from 56 patients with metastatic or unresectable malignant melanoma, receiving treatment with ipilimumab in a national Phase IV study (NCT0268196). Expression of a panel of 17 inflammatory‐related markers reflecting different pathways including extracellular matrix remodeling and fibrosis, vascular inflammation and monocyte/macrophage activation were measured at baseline and the second and/or third course of treatment with ipilimumab. Six candidate proteins [endostatin, osteoprotegerin (OPG), C‐reactive protein (CRP), pulmonary and activation‐regulated chemokine (PARC), growth differentiation factor 15 (GDF15) and galectin‐3 binding‐protein (Gal3BP)] were persistently higher in non‐survivors. In particular, high Gal3BP and endostatin levels were also independently associated with poor 2‐year survival after adjusting for lactate dehydrogenase, M‐stage and number of organs affected. A 1 standard deviation increase in endostatin gave 1·74 times [95% confidence interval (CI) = 1·10–2·78, P = 0·019] and for Gal3BP 1·52 times (95% CI = 1·01–2·29, P = 0·047) higher risk of death in the adjusted model. Endostatin and Gal3BP may represent prognostic biomarkers for patients on ipilimumab treatment in metastatic melanoma and should be further evaluated. Owing to the non‐placebo design, we could only relate our findings to prognosis during ipilimumab treatment.

Rifaximin alters gut microbiota profile, but does not affect systemic inflammation - a randomized controlled trial in common variable immunodeficiency

Common variable immunodeficiency (CVID) patients have reduced gut microbial diversity compared to healthy controls. The reduced diversity is associated with gut leakage, increased systemic inflammation and ten "key" bacteria that capture the gut dysbiosis (dysbiosis index) in CVID. Rifaximin is a broad-spectrum non-absorbable antibiotic known to reduce gut leakage (lipopolysaccharides, LPS) in liver disease. In this study, we explored as a 'proof of concept' that altering gut microbial composition could reduce systemic inflammation, using CVID as a disease model. Forty adult CVID patients were randomized, (1:1) to twice-daily oral rifaximin 550 mg versus no treatment for 2 weeks in an open-label, single-centre study. Primary endpoints were reduction in plasma/serum levels of soluble (s) CD14, sCD25, sCD163, neopterin, CRP, TNF, LPS and selected cytokines measured at 0, 2 and 8 weeks. Secondary endpoint was changes in intra-individual bacterial diversity in stool samples. Rifaximin-use did not significantly change any of the inflammation or gut leakage markers, but decreased gut microbial diversity compared with no treatment (p = 0.002). Importantly, the gut bacteria in the CVID dysbiosis index were not changed by rifaximin. The results suggest that modulating gut microbiota by rifaximin is not the chosen intervention to affect systemic inflammation, at least not in CVID.

An association between YKL-40 and type 2 diabetes in psychotic disorders

OBJECTIVE

This study examines if YKL-40 is increased in individuals with psychotic disorders and if elevated YKL-40 levels at baseline is associated with subsequent development of type 2 diabetes.

METHOD

A total of 1383 patients with a diagnosis of schizophrenia or affective psychosis and 799 healthy controls were recruited in the period 2002-2015. Plasma YKL-40 and metabolic risk factors were measured and medication was recorded. Using national registry data, association between baseline risk factors and later development of type 2 diabetes was assessed using Cox proportional hazards models.

RESULTS

Plasma YKL-40 was higher in patients vs. healthy controls also after adjusting for metabolic risk factors, with no difference between the schizophrenia and affective psychosis groups. Patients were diagnosed with type 2 diabetes at a significantly younger age. Multivariate Cox regression analyses showed that elevated YKL-40 (hazard ratio (HR) = 5.6, P = 0.001), elevated glucose (HR = 3.6, P = 0.001), and schizophrenia diagnosis (HR = 3.0, P = 0.014) at baseline were associated with subsequent development of type 2 diabetes.

CONCLUSIONS

Patients with psychotic disorders have at baseline increased levels of YKL-40 beyond the effect of comorbid type 2 diabetes and metabolic risk factors. Elevated YKL-40 level at baseline is associated with later development of type 2 diabetes.

Persistently Elevated Levels of von Willebrand Factor Antigen in HIV Infection

Levels of circulating von Willebrand factor (vWf) antigen are thought to reflect endothelial involvement in various disorders. In the present study we found markedly elevated plasma levels of vWf in HIV-infected patients demonstrated on both cross-sectional and longitudinal testing. Notably, we found that a persistent rise in vWf antigen was associated with progression of HIV-related disease. This elevation of vWf antigen represented functionally normal vWf as evaluated by plasma FVIII, ristocetin cofactor assay and vWf multimer analyses. While HIV-infected patients showed enhanced platelet activation, platelets did not contribute substantially to the increased vWf levels. The high vWf levels were significantly correlated with high viral load, and during HAART, the pronounced decline in HIV RNA levels was accompanied by a corresponding decrease in vWf. The persistent elevation of functionally normal vWf during HIV infection, most probably reflecting a persistent endothelial cell activation, may have an important role in the pathogenesis of HIV infection.

Persistent increase in TNF and IL-1 markers in severe mental disorders suggests trait-related inflammation: a one year follow-up study

OBJECTIVE

We evaluated if plasma levels of inflammatory markers are persistently altered in severe mental disorders with psychotic symptoms or associated with state characteristics in a longitudinal study.

METHODS

Soluble tumor necrosis factor receptor 1 (sTNF-R1), interleukin-1 receptor antagonist (IL-1Ra), von Willebrand factor (VWF), and osteoprotegerin (OPG) were measured in schizophrenia (n = 69) and affective (n = 55) spectrum patients at baseline and at one-year follow-up, and compared to healthy controls (HC) (n = 92) with analysis of covariance. Association between change in symptoms and inflammatory markers was analyzed with mixed-effects models.

RESULTS

sTNF-R1 was higher in the schizophrenia (P < 0.0001) and affective disorders (P = 0.02) compared to HC, while IL-1Ra was higher in schizophrenia (P = 0.01) compared to HC at one year follow-up. There were no significant differences between schizophrenia and affective groups; however, levels in the affective group were in between schizophrenia and HC for sTNF-R1 and IL-1Ra. There were no significant associations between change in symptoms and inflammatory markers.

CONCLUSION

Persistently increased sTNF-R1 and IL-1Ra after one year in patients with severe mental disorders primarily reflecting data from the schizophrenia group may suggest that inflammation is a trait phenomenon, and not only the result of stress-related mechanisms associated with acute episodes.

High physical fitness is associated with reduction in basal- and exercise-induced inflammation

C-reactive protein (CRP) increases after strenuous exercise. It has been a concern that prolonged strenuous exercise may be harmful and induce a deleterious inflammatory response. The purpose of this study was to (a) assess and quantify the magnitude of CRP response following an endurance cycling competition in healthy middle-aged recreational cyclists. (b) Identify important determinants of this response. (c) Identify the relationship between CRP, myocardial damage (cardiac Troponin I (cTnI)), and myocardial strain (B-type natriuretic peptide [BNP]). (d) Identify the relationship between CRP and clinical events, defined as utilization of healthcare services or self-reported unusual discomfort. Race time was used as a measure of physical fitness. A total of 97 individuals (43±10 years of age, 74 [76%] males) were assessed prior to and 0, 3, and 24 hours following the 91-km mountain bike race "Nordsjørittet" (Sandnes, Norway, June 2013). There was a highly significant increase in CRP from baseline to 24 hours (0.9 (0.5-1.8) mg/L vs. 11.6 (6.0-17.5) mg/L (median[IQR]), P<.001), with no correlation of CRP to cTnI and BNP at any time-point. CRP was strongly correlated to race time at baseline (r=.38, P<.001) and at 24 hours following the race (r=.43, P<.001), In multivariate models, race time was an independent predictor of CRP both at baseline and at 24 hours (P<.01). There was no relationship between CRP levels and clinical events. In conclusion, high physical fitness was associated with reduction in both basal- and exercise-induced CRP. No adverse relationship was found between high intensity physical exercise, CRP levels, and outcomes.

Serum osteoprotegrin (OPG) in subclinical atherosclerosis in systemic lupus erythematosus

Introduction Osteoprotegerin (OPG) is a member of the tumor necrosis factor (TNF) receptor family. It has recently been demonstrated that OPG is produced by a variety of tissues, including the cardiovascular system (heart, arteries, veins), lung, kidney, immune tissues, and bone. The OPG-RANKL signaling pathway is strongly related to vascular calcification. We determined the association of this biomarker with subclinical atherosclerosis in systemic lupus erythematous (SLE). Methods We measured OPG and markers of subclinical atherosclerosis (coronary artery calcium (CAC), carotid intima-media thickness (cIMT) carotid plaque) in 166 SLE patients (91% female, 64% Caucasian, 31% African American, 5% others, mean age 45 years). Subgroups of patients with different levels of OPG level were compared with respect to average levels of CAC, cIMT, and with respect to presence of carotid plaque. Age was adjusted for using multiple regression. Results OPG was highly correlated with age ( p < 0.0001). Individuals with higher levels of OPG tended to have higher measures of CAC, cIMT, and more carotid plaque. However, after adjustment for age, these associations, while still positive, were no longer statistically significant. Conclusion In our study much of the association observed was due to confounding by age, and after adjusting for age, our findings do not rule out the possibility of a null association.

Altered gut microbiota profile in common variable immunodeficiency associates with levels of lipopolysaccharide and markers of systemic immune activation

Common variable immunodeficiency (CVID) is the most common symptomatic primary immunodeficiency characterized by low immunoglobulin (Ig)G and IgA, and/or IgM. In addition to bacterial infections, a large subgroup has noninfectious inflammatory and autoimmune complications. We performed 16S ribosomal RNA-based profiling of stool samples in 44 CVID patients, 45 patients with inflammatory bowel disease (disease controls), and 263 healthy controls. We measured plasma lipopolysaccharide (LPS) and markers of immune cell activation (i.e., soluble (s) CD14 and sCD25) in an expanded cohort of 104 patients with CVID and in 30 healthy controls. We found a large shift in the microbiota of CVID patients characterized by a reduced within-individual bacterial diversity (alpha diversity, P<0.001) without obvious associations to antibiotics use. Plasma levels of both LPS (P=0.001) and sCD25 (P<0.0001) were elevated in CVID, correlating negatively with alpha diversity and positively with a dysbiosis index calculated from the taxonomic profile. Low alpha diversity and high dysbiosis index, LPS, and immune markers were most pronounced in the subgroup with inflammatory and autoimmune complications. Low level of IgA was associated with decreased alpha diversity, but not independently from sCD25 and LPS. Our findings suggest a link between immunodeficiency, systemic immune activation, LPS, and altered gut microbiota.

Rickettsia conorii is a potent complement activator in vivo and combined inhibition of complement and CD14 is required for attenuation of the cytokine response ex vivo

Mediterranean spotted fever caused by Rickettsia conorii is a potentially lethal disease characterized by vascular inflammation affecting multiple organs. Studies of R. conorii so far have focused on activation of inflammatory cells and their release of inflammatory cytokines, but complement activation has not been investigated in R. conorii-infected patients. Here, we performed a comprehensive analysis of complement activation markers and the soluble cross-talking co-receptor CD14 (sCD14) in plasma from R. conorii-infected patients. The clinical data were supplemented with ex vivo experiments where the cytokine response was characterized in human whole blood stimulated with R. conorii. Complement activation markers at the level of C3 (C3bc, C3bBbP) and terminal pathway activation (sC5b-9), as well as sCD14, were markedly elevated (p <0.01 for all), and closely correlated (p <0.05 for all), in patients at admission compared with healthy matched controls. All tested markers were significantly reduced to baseline values at time of follow up. Rickettsia conorii incubated in human whole blood was shown to trigger complement activation accompanied by release of the inflammatory cytokines interleukin-1β (IL-1β), IL-6, IL-8 and tumour necrosis factor. Whereas inhibition of either C3 or CD14 had only a minor effect on released cytokines, combined inhibition of C3 and CD14 resulted in significant reduction, virtually to baseline levels, of the four cytokines (p <0.05 for all). Our data show that complement is markedly activated upon R. conorii infection and complement activation is, together with CD14, responsible for a major part of the cytokine response induced by R. conorii in human whole blood.

Circulating annexin A5 predicts mortality in patients with heart failure

BACKGROUND

Natriuretic peptides are currently used to predict mortality in patients with heart failure (HF). However, novel independent biomarkers are needed to improve risk stratification in these patients. We hypothesized that annexin A5 (anxA5) would be highly expressed by organs which are generally affected by HF and that circulating anxA5 levels would predict mortality in HF patients.

METHODS

We prospectively determined the diagnostic value of anxA5, N-terminal pro-B-type natriuretic peptide (NT-proBNP), C-reactive protein (CRP) and estimated glomerular filtration rate (eGFR) to predict mortality in 180 HF patients during a median follow-up of 3.6 years. Studies were conducted with anxA5(-/-) mice to investigate the underlying mechanisms.

RESULTS

AnxA5 levels were significantly elevated in HF patients compared to healthy control subjects. Cox regression analysis demonstrated that anxA5, NT-proBNP and eGFR all predict mortality independently. AnxA5 significantly improved the diagnostic efficiency of NT-proBNP alone (improvement of c-statistic from 0.662 to 0.705, P < 0.001) and also combined with eGFR and CRP (improvement of c-statistic from 0.675 to 0.738, P < 0.001) to predict mortality in the Cox regression model. Receiver operating characteristic curve analysis showed that anxA5 predicted 3-year survival (area under curve 0.708) with an optimal cut-off value of 2.24 ng mL(-1) . Using anxA5(-/-) mice, we demonstrated that anxA5 is highly expressed in organs that are often affected by HF including lung, kidney, liver and spleen. Lysis of these organs in vitro resulted in a marked and significant increase in anxA5 concentrations.

CONCLUSION

AnxA5 improves the diagnostic efficiency of conventional biomarkers to predict mortality in HF patients. Whereas natriuretic peptides originate from the myocardium, high circulating anxA5 levels in patients with HF are likely to reflect peripheral organ damage secondary to HF.

Association between cytokine levels, verbal memory and hippocampus volume in psychotic disorders and healthy controls

OBJECTIVE

We investigated whether elevated plasma levels of immune markers were associated with verbal memory and hippocampal subfield volumes in patients with severe mental illnesses and in healthy controls.

METHOD

In total, 230 patients with a broad DSM-IV schizophrenia spectrum illness or bipolar disorder and 236 healthy controls were recruited. Memory was assessed using the Wechsler Memory Scale-Third Edition (WMS-III) Logical Memory immediate and delayed recall, and the California Verbal Learning Test summed recall over learning list (CVLT learning) and delayed free recall. We measured plasma levels of soluble tumor necrosis factor receptor 1 (sTNF-R1), interleukin-1 receptor antagonist, interleukin-6, von Willebrand factor, osteoprotegerin, high-sensitivity C-reactive protein and sCD40 ligand. Hippocampal subfield estimates were obtained using FreeSurfer.

RESULTS

We found a moderate negative association between sTNF-R1 and performance on verbal memory learning and recall tests as measured by the WMS-III Logical Memory after controlling for age, sex and diagnosis. We observed no interaction effect of diagnosis and sTNF-R1 on memory scores. We also found a nominally significant positive association between CVLT learning and hippocampal volumes.

CONCLUSION

The findings suggest a role for immune involvement in memory independent of severe mental disorders and may support the 'bigger is better' hypothesis of hippocampal subfield volumes.

NLRP3 inflammasome activation during myocardial ischemia reperfusion is cardioprotective

BACKGROUND

The innate immune receptor NLRP3 recognizes tissue damage and initiates inflammatory processes through formation multiprotein complexes with the adaptor protein ASC and caspase-1, i.e. NLRP3 inflammasomes, which through cleavage of pro-IL-1β mediates release of bioactive IL-1β. We hypothesized that NLRP3 mediates tissue damage during acute myocardial infarction (MI) and sought to investigate the mechanisms herein in an experimental MI model in mice.

METHODS AND RESULTS

The left coronary artery (LCA) of WT, NLRP3(-/-) and ASC(-/-) mice of both genders was ligated for 30 min followed by 3 or 24 h reperfusion. For pre-conditioning studies, the TLR2 agonist Pam3CSK4 or PBS was injected intraperitoneally 60 min prior to LCA ligation. For mechanistic investigations, blood plasmas and left ventricle tissues were collected, and a hypothesis-driven selection of protein or mRNA targets was investigated. Surprisingly, hearts from NLRP3-deficient mice featured larger infarct size than WT mice (p = 0.0048). In general, there were only modest changes with no significant pattern in myocardial infiltration of neutrophils and macrophages and systemic and myocardial cytokine expression between the three genotypes. Preconditioning with the TLR2 agonist Pam3CSK4 induced Akt phosphorylation and reduced infarct size in WT but not NLRP3 -or ASC -deficient hearts.

CONCLUSION

Absence of NLRP3 results in increased myocardial infarct size after in vivo ischemia reperfusion, seemingly due to dysfunction of the cardioprotective RISK pathway. Our data imply that NLRP3 contributes to cardio-protection during I/R and do not support a role for NLRP3 or ASC inhibition in the management of acute MI including revascularization therapy.

The Effect of Everolimus Initiation and Calcineurin Inhibitor Elimination on Cardiac Allograft Vasculopathy in De Novo Recipients: One-Year Results of a Scandinavian Randomized Trial

Early initiation of everolimus with calcineurin inhibitor therapy has been shown to reduce the progression of cardiac allograft vasculopathy (CAV) in de novo heart transplant recipients. The effect of de novo everolimus therapy and early total elimination of calcineurin inhibitor therapy has, however, not been investigated and is relevant given the morbidity and lack of efficacy of current protocols in preventing CAV. This 12-month multicenter Scandinavian trial randomized 115 de novo heart transplant recipients to everolimus with complete calcineurin inhibitor elimination 7-11 weeks after HTx or standard cyclosporine immunosuppression. Ninety-five (83%) patients had matched intravascular ultrasound examinations at baseline and 12 months. Mean (± SD) recipient age was 49.9 ± 13.1 years. The everolimus group (n = 47) demonstrated significantly reduced CAV progression as compared to the calcineurin inhibitor group (n = 48) (ΔMaximal Intimal Thickness 0.03 ± 0.06 and 0.08 ± 0.12 mm, ΔPercent Atheroma Volume 1.3 ± 2.3 and 4.2 ± 5.0%, ΔTotal Atheroma Volume 1.1 ± 19.2 mm(3) and 13.8 ± 28.0 mm(3) [all p-values ≤ 0.01]). Everolimus patients also had a significantly greater decline in levels of soluble tumor necrosis factor receptor-1 as compared to the calcineurin inhibitor group (p = 0.02). These preliminary results suggest that an everolimus-based CNI-free can potentially be considered in suitable de novo HTx recipients.

Microbiota-dependent metabolite trimethylamine-N-oxide is associated with disease severity and survival of patients with chronic heart failure

OBJECTIVES

Recent metabolomic, experimental and clinical studies have demonstrated that trimethylamine-N-oxide (TMAO), a microbiota-dependent metabolite from dietary phosphatidylcholine and carnitine, is a strong predictor of coronary artery disease (CAD). This finding suggests a link between the gut microbiota and atherosclerosis. The potential impact of TMAO in chronic heart failure (HF) is unknown. We hypothesized that TMAO levels would provide prognostic information about adverse outcomes in chronic HF.

DESIGN

Prospective, observational study including 155 consecutive patients with chronic HF. In addition, 100 patients with stable CAD without HF and 33 matched healthy individuals were included as controls. Plasma levels of TMAO and its precursors choline and betaine were measured, and associations with symptoms, aetiology and transplant-free survival in the patients with HF were explored.

RESULTS

Plasma levels of TMAO (P = 0.01), choline (P < 0.001) and betaine (P < 0.001) were elevated in patients with chronic HF compared to control subjects, with the highest levels in patients with New York Heart Association (NYHA) classes III and IV. Furthermore, TMAO levels were highest in individuals with ischaemic HF, followed by those with stable CAD and nonischaemic HF. TMAO, but not choline or betaine, was associated with reduced transplant-free survival: approximately 50% of patients in the upper tertile of TMAO levels died or received a heart transplant during 5.2 years of follow-up (unadjusted Cox-regression: hazard ratio 2.24, 95% confidence interval 1.28-3.92, P = 0.005).

CONCLUSIONS

TMAO levels were elevated in patients with HF and associated with NYHA class, ischaemic aetiology and adverse outcomes. Future studies should focus on gut microbiota, dietary composition and intestinal dysfunction in relation to TMAO levels and clinical outcome in HF.

Circulating levels of inflammatory cytokines and cytokine receptors in patients with ankylosing spondylitis: a cross-sectional comparative study

OBJECTIVES

Insight into the most important inflammatory pathways in ankylosing spondylitis (AS) could be of importance in risk stratification and the development of treatment strategies. Therefore, we aimed to compare circulating levels of inflammatory biomarkers between AS patients and controls, and explore associations between these biomarkers and clinical measures of disease activity.

METHOD

In a cross-sectional study, 143 AS patients were compared with 124 population controls. Blood samples were analysed by immunoassays for interleukin (IL)-6, IL-17a, IL-23, soluble tumour necrosis factor receptor 1 (sTNF-R1) and 2 (sTNF-R2), and osteoprotegerin (OPG). Disease activity was measured by the AS Disease Activity Score (ASDAS) and the Bath AS Disease Activity Index (BASDAI).

RESULTS

Analysis of covariance (ANCOVA) demonstrated elevated plasma levels of sTNF-R1 [geometrical mean 0.94 (95% CI 0.88-1.00) vs. 0.83 (95% CI 0.78-0.89) ng/mL, p < 0.01] and OPG (2.3, 95% CI 2.1-2.4 vs. 2.0, 95% CI 1.9-2.2 ng/mL, p = 0.02) and, although not significant, of IL-23 (122, 95% CI 108-139 vs. 106, 95% CI 93-120 pg/mL, p = 0.07) in AS patients vs.

CONTROLS

More AS patients had a high level of sTNF-R2 than controls (22 vs. 1, p < 0.01). No differences between the groups were seen for IL-6 and IL-17a. In patients, no significant associations were seen between inflammatory markers and disease activity measures after adjusting for personal characteristics.

CONCLUSION

Significantly higher plasma levels of sTNF-R1, sTNF-R2, and OPG and numerically but non-significantly higher levels of IL-23 were found in AS patients compared to controls, indicating that these cytokines and cytokine receptors are important inflammatory pathways. Clinical measures of disease activity were not significantly correlated with circulating inflammatory markers.

IP-10 differentiates between active and latent tuberculosis irrespective of HIV status and declines during therapy

OBJECTIVES

Biomarkers for diagnosis and therapy efficacy in tuberculosis (TB) are requested. We have studied biomarkers that may differentiate between active and latent TB infection (LTBI), the influence of HIV infection and changes during anti-TB chemotherapy.

METHODS

Thirty-eight plasma cytokines, assessed by multiplex and enzyme immunoassays, were analyzed in patients with active TB before and during 24 weeks of anti-TB chemotherapy (n = 65), from individuals with LTBI (n = 34) and from QuantiFERON-TB (QFT) negative controls (n = 65). The study participants were grouped according to HIV status.

RESULTS

Plasma levels of the CXC chemokine IP-10 and soluble TNF receptor type 2 (sTNFr2) significantly differentiated active TB from the LTBI group, irrespective of HIV status. In the HIV-infected group the sensitivity and specificity was 100% for IP-10 with a cut-off of 2547 pg/mL. Plasma IP-10 declined gradually during anti-TB chemotherapy (12-24 weeks, p = 0.002) to a level comparable to LTBI and QFT negative control groups. sTNFr2 fluctuated throughout therapy, but was decreased after 12-24 weeks (p = 0.006).

CONCLUSIONS

IP-10 distinguished with high accuracy active TB from LTBI irrespective of HIV infection and declined during anti-TB chemotherapy. Plasma IP-10 may serve as a diagnostic biomarker to differentiate between the stages of TB infection and for monitoring therapy efficacy.

The collagen cross-linking enzyme lysyl oxidase is associated with the healing of human atherosclerotic lesions

BACKGROUND

Acute clinical complications of atherosclerosis such as myocardial infarction (MI) and ischaemic stroke are usually caused by thrombus formation on the ruptured plaque surface. Collagen, the main structural protein of the fibrous cap, provides mechanical strength to the atherosclerotic plaque. The integrity of the fibrous cap depends on collagen fibre cross-linking, a process controlled by the enzyme lysyl oxidase (LOX).

METHODS AND RESULTS

We studied atherosclerotic plaques from human carotid endarterectomies. LOX was strongly expressed in atherosclerotic lesions and detected in the regions with ongoing fibrogenesis. Higher LOX levels were associated with a more stable phenotype of the plaque. In the studied population, LOX mRNA levels in carotid plaques predicted the risk for future MI. Within the lesion, LOX mRNA levels correlated positively with levels of osteoprotegerin (OPG) and negatively with markers of immune activation. The amount of LOX-mediated collagen cross-links in plaques correlated positively also with serum levels of OPG.

CONCLUSIONS

Lysyl oxidase may contribute to the healing of atherosclerotic lesions and to the prevention of its lethal complications. Mediators of inflammation may control LOX expression in plaques and hence plaque stability.