The alternative complement pathway is dysregulated in patients with chronic heart failure

The plasma proteome is linked to echocardiographic parameters and stages of diastolic dysfunction, across the ejection fraction spectrum

INTRODUCTION

This study investigates the interplay between the circulating plasma proteome and echocardiographic parameters in patients across the spectrum of heart failure (HF) (ranging from patients at risk of/with preserved (HFpEF) to reduced (HFrEF) ejection fraction).

METHODS

Data from two cohort studies, HELPFul and Bio-SHiFT, were analyzed. We measured 4210 circulating plasma proteins in a total of 750 patients using SomaScan® proteomics. Echocardiographic parameters in both studies included left ventricular ejection fraction (LVEF) and the ratio of the peak early left ventricular (LV) filling velocity and early diastolic mitral annular velocity (E/e'). In further analyses, we classified patients in left ventricular diastolic dysfunction (LVDD) groups according to the prevailing guidelines.

RESULTS

Out of the 4210 plasma proteins, 21 proteins were significantly associated with E/e' in patients at risk of/with HFpEF, whereas 9 proteins were associated with LVEF. Approximately 43 % (n = 1822) of the proteins showed significant interactions between E/e' and HF subtype. All of these proteins showed weaker associations with E/e' in patients at risk of/with HFpEF compared to the ones with HFrEF. These proteins were related to the extracellular matrix, cellular processes, insulin-like growth factor (IGF) transport, metabolic and catabolic processes. Furthermore, comparisons between LVDD groups and those with normal diastolic function identified 40 proteins associated with grade 2 (top 5: Cystatin C, TMEDA, NT-proBNP, GDF-15 and PXDN) and 198 with grade 3 LVDD (top 5: NT-proBNP, Cystatin C, PXDN, RNasa1, and Factor D).

CONCLUSION

In patients at risk of/with HFpEF, biological processes and pathways showed weaker associations with E/e' compared to patients with HFrEF. Varying pathways identified through proteomics were associated with deterioration of LVDD across the ejection fraction spectrum. Our results are in line with the mechanistic frameworks currently thought to underlie the various types of HF.

Aortic aneurysm and dissection: complement and precision medicine in aortic disease

Aortic disease encompasses life-threatening conditions such as aortic aneurysm and dissection, which are associated with high prevalence, morbidity, and mortality. The complement system, a key component of innate immunity, not only defends against pathogens but also maintains tissue homeostasis. Recent discoveries have expanded its role beyond immunity, linking complement dysregulation to numerous diseases and positioning it as a target for pharmacotherapy. Complement-based treatments for precision medicine are emerging, with several pharmaceuticals either already approved or under investigation. In aortic disease, complement activation and dysregulation have unveiled novel mechanisms and clinical implications. Human and experimental studies suggest that all three complement pathways contribute to disease pathophysiology. The complement system induces direct cellular damage via the membrane attack complex, as well as matrix-metalloproteinase (MMP)-associated tissue damage by promoting MMP-2 and MMP-9 expression. The anaphylatoxins C3a and C5a exacerbate disease by recruiting immune cells and triggering proinflammatory responses. Examples include neutrophil extracellular trap formation and cytokine release by polymorphonuclear neutrophils. These findings highlight the complement system as a promising novel diagnostic and therapeutic target in aortic disease with potential for individualized treatment. However, gaps remain, emphasizing the need for standardized multisite preclinical studies to improve reproducibility and translation. Biomarker studies must also be validated across diverse patient cohorts for clinical applicability. This review examines current knowledge regarding complement in aortic disease, aiming to evaluate its potential for innovative diagnostic and personalized treatment strategies.

Mitochondrial injury and complement dysregulation are drivers of pathological inflammation in viral myocarditis

Enteroviruses cause nearly 1 billion global infections annually and are associated with a diverse array of human illnesses. Among these, myocarditis and the resulting chronic inflammation have been recognized as major contributing factors to virus-induced heart failure. Despite our growing understanding, very limited therapeutic strategies have been developed to address the pathological consequences of virus-induced chronic innate immune activation. Coxsackievirus B3 (CVB3) was used as a model cardiotropic enterovirus. We leveraged in vitro cell-based studies to investigate cardiomyocyte and macrophage interaction during CVB3 infection, as well as animal studies and unique human cardio specimens to evaluate mechanisms of viral heart injury. We present evidence that viral myocarditis is in part exacerbated by pathological activation of the complement pathway in cells, mice, and human cardiac tissues. We demonstrate unique cell type-specific responses to viral infection that are exacerbated by mitochondrial injury in cardiomyocytes and NFκB-dependent pro-inflammatory response in macrophages. Macrophages are robustly activated by damage-associated mitochondrial components, including mitochondrial proteins and lipid extracts. Mechanistically, we identify complement protective factors CD59/protectin and CD55/DAF as novel targets of viral proteinase that acts to release the brakes on complement-mediated autoinjury. Collectively, our study highlights a novel mechanism that can act as a potential contributor to CVB3 pathogenesis through mitochondrial injury-mediated autoimmunity.

IMPORTANCE

This study sheds light on how enteroviruses, specifically coxsackievirus B3, may contribute to heart failure by triggering harmful immune responses in the heart. We discovered that viral infections in heart cells cause mitochondrial damage, which in turn activates a destructive immune response involving the complement system. This immune activation is one of the significant contributors that lead to further injury of heart tissues, worsening the damage caused by the virus. Additionally, we identified key protective molecules that are targeted and disrupted by the virus, allowing the immune system to attack the heart even more aggressively. Understanding these mechanisms may provide additional insights into how viral infections can lead to chronic heart conditions and suggests potential therapeutic targets to prevent or reduce heart damage in patients affected by viral myocarditis.

Alternative Complement Pathway in Carotid Atherosclerosis: Low Plasma Properdin Levels Associate With Long-Term Cardiovascular Mortality

BACKGROUND

Complement activation may promote atherosclerosis. Yet, data on the to which extent complement, and more specifically the alternative complement pathway, is activated in patients with carotid atherosclerosis and related to adverse outcome in these patients, are scarce.

METHODS AND RESULTS

We measured, by ELISA, plasma levels of factor D, properdin, C3bBbP (C3 convertase), and factor H in patients with advanced carotid atherosclerosis in a Discovery (n=324) and in a Validation (n=206) cohort in relation to adverse outcome (mean follow-up 7.8 and 6.6 years, respectively). Our major findings were as follows. Compared with healthy controls, patients with carotid atherosclerosis had increased plasma levels of factor D, properdin, and C3bBbP (P<0.001), but not factor H, an inhibitor of the alternative complement pathway, compared with controls. Although patients with carotid atherosclerosis had elevated levels of properdin compared with controls, within these patients, low plasma levels of properdin (ie,

CONCLUSIONS

We show a strong and independent association of low plasma properdin levels with cardiovascular mortality in 2 cohorts. Conversely, the plaque properdin levels linked to features of plaque vulnerability, potentially reflecting increased deposition at the site of inflammation or local production of properdin in the atherosclerotic lesion indicating local enhanced alternative complement pathway activation.

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Key Words

• alternative complement pathway
• carotid atherosclerosis
• complement
• plaque vulnerability
• properdin
• stroke

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MESH Headings

• Humans
• Male
• Female
• Properdin/metabolism
• Properdin/analysis
• Carotid Artery Diseases/mortality
• Carotid Artery Diseases/blood
• Carotid Artery Diseases/immunology
• Middle Aged
• Complement Pathway, Alternative
• Aged
• Biomarkers/blood
• Risk Factors
• Prognosis
• Complement Factor D/metabolism
• Complement Factor D/analysis
• Case-Control Studies
• Time Factors
• Enzyme-Linked Immunosorbent Assay
• Complement Factor H/metabolism

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Grants

• South‐Eastern Norway Regional Health Authority
• Skåne University Hospital
• Swedish Society for Medical Research
• Swedish Stroke Association
• Swedish Foundation for Strategic Research
• Region Skåne

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Affiliation(s)

Mieke C. Louwe Research Institute of Internal Medicine, Oslo University HospitalOsloNorway
Chrysostomi Gialeli Department of Clinical Sciences MalmöLund UniversityLundSweden
Annika E. Michelsen Research Institute of Internal Medicine, Oslo University HospitalOsloNorway Institute of Clinical Medicine, Faculty of Medicine, University of OsloNorway
Sverre Holm Research Institute of Internal Medicine, Oslo University HospitalOsloNorway
Andreas Edsfeldt Department of Clinical Sciences MalmöLund UniversityLundSweden Department of CardiologyMalmö, Skåne University HospitalMalmöSweden Wallenberg Center for Molecular MedicineLund UniversityLundSweden
Karolina Skagen Institute of Clinical Medicine, Faculty of Medicine, University of OsloNorway Department of NeurologyOslo University Hospital RikshospitaletOsloNorway
Tove Lekva Research Institute of Internal Medicine, Oslo University HospitalOsloNorway
Maria Belland Olsen Research Institute of Internal Medicine, Oslo University HospitalOsloNorway
Vigdis Bjerkeli Research Institute of Internal Medicine, Oslo University HospitalOsloNorway
Therese Schjørlien Institute of Clinical Medicine, Faculty of Medicine, University of OsloNorway Department of NeurologyOslo University Hospital RikshospitaletOsloNorway
Kristine Stø Institute of Clinical Medicine, Faculty of Medicine, University of OsloNorway Department of NeurologyOslo University Hospital RikshospitaletOsloNorway
Xiang Yi Kong Research Institute of Internal Medicine, Oslo University HospitalOsloNorway
Tuva B. Dahl Research Institute of Internal Medicine, Oslo University HospitalOsloNorway
Per H. Nilsson Department of ImmunologyOslo University Hospital Rikshospitalet and University of OsloNorway Linnaeus Centre for Biomaterials ChemistryLinnaeus UniversityKalmarSweden
Peter Libby Division of Cardiovascular MedicineBrigham and Women’s Hospital, Harvard Medical SchoolBostonMAUSA
Pål Aukrust Research Institute of Internal Medicine, Oslo University HospitalOsloNorway Institute of Clinical Medicine, Faculty of Medicine, University of OsloNorway Section of Clinical Immunology and Infectious DiseasesOslo University Hospital RikshospitaletOsloNorway
Tom Eirik Mollnes Department of ImmunologyOslo University Hospital Rikshospitalet and University of OsloNorway Research LaboratoryNordland HospitalBodøNorway Centre of Molecular Inflammation ResearchNorwegian University of Science and TechnologyTrondheimNorway
Thor Ueland Research Institute of Internal Medicine, Oslo University HospitalOsloNorway Institute of Clinical Medicine, Faculty of Medicine, University of OsloNorway K. G. Jebsen Thrombosis Research and Expertise CenterUniversity of TromsøNorway
Mona Skjelland Institute of Clinical Medicine, Faculty of Medicine, University of OsloNorway Department of NeurologyOslo University Hospital RikshospitaletOsloNorway
Isabel Gonçalves Department of Clinical Sciences MalmöLund UniversityLundSweden Department of CardiologyMalmö, Skåne University HospitalMalmöSweden
Bente Halvorsen Research Institute of Internal Medicine, Oslo University HospitalOsloNorway Institute of Clinical Medicine, Faculty of Medicine, University of OsloNorway

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Collaborators Collapse

Urine Complement Factor Ba Identifies Persistent Acute Kidney Injury and Organ Failures in Critically Ill Adults

Introduction

Critically ill adults with acute kidney injury (AKI) have high morbidity and mortality and lack treatment options. We assessed the association between complement activation (urine Ba fragment levels), and AKI and organ failures.

Methods

A biorepository of critically ill adults was leveraged. AKI staging was based on the Kidney Disease Improving Global Outcomes serum creatinine (sCr) criteria. AKI recovery was defined as sCr reduction to <0.3 mg/dl above baseline within 48 hours after AKI diagnosis. Persistent AKI was defined as need for renal replacement or no sCr recovery. Urine was obtained at intensive care unit (ICU) admission, and at 12 and 24 hours after admission; and urine Ba levels were quantitated via enzyme-linked immunosorbent assay and natural log transformed. Regression analyses were performed to test the association between urine Ba and organ failure outcomes. We adjusted for age and the acute physiology and chronic health evaluation II (APACHE-II) score, which is used to classify ICU severity of illness.

Results

A total of 439 patients were included: 252 without AKI, 124 with stage 1 AKI, 43 with stage 2 AKI, and 20 with stage 3 AKI. After adjusting for covariates, urine Ba increased as AKI stage increased. Urine Ba was higher in patients with persistent AKI compared with patients with AKI recovery and without AKI. Increased urine Ba was associated with worse organ failure outcomes (fewer ventilator, ICU, and inotrope-free days, and fewer days alive).

Conclusion

Urine Ba is increased in patients with severe AKI and discriminates between patients who have AKI recovery and patients who develop persistent AKI. A doubling of urine Ba was associated with a 6.6-fold increased odds of persistent AKI. Future studies to validate these findings and to trial complement factor B inhibition are warranted.

Utility of factor D and other alternative complement factors as biomarkers in systemic sclerosis-associated pulmonary arterial hypertension (SSc-PAH)

BACKGROUND

Activation of the complement cascade is thought to play a role in scleroderma vasculopathy. We previously showed that complement factor D was elevated in patients with limited cutaneous SSc and pulmonary arterial hypertension (PAH). In this study, we sought to assess multiple relevant components of the complement cascade to determine if they are altered in SSc-PAH, as well as their potential utility as biomarkers of disease severity and progression.

METHODS

Complement components (n = 14) were measured using multiplex assays in 156 patients with SSc-PAH from a multi-site repository and were compared to 33 patients with SSc without PAH, and 40 healthy controls. Data were evaluated for correlations between complement levels, right heart catheterization measures, and clinical endpoints including 6-minute walk distance. To assess complement longitudinally, serum complement levels were assayed at 0, 4, 12, 24, 36 and 48 weeks in 52 SSc-PAH patients who participated in a prior clinical trial.

RESULTS

We found that factor D was significantly elevated in SSc-PAH compared to SSc without PAH (p < 0.0001) and was highly sensitive and specific for SSc-PAH (AUC=0.82, p < 0.001). In SSc-PAH patients, alterations in factor H, C4, and factor D were associated with measures of PAH disease severity including right heart catheterization measurements (cardiac output, right atrial pressure, and VO2 max), survival, and 6-minute walk distance. No significant changes in complement levels or clinical associations were seen over time or associated with treatment in the longitudinal clinical trial study.

CONCLUSION

Our work confirms prior studies demonstrating a role for complement activation in SSc vascular disease and elevations of factor D in a large SSc-PAH population. Further, factor H and other complement factors are associated with severity of PAH including mortality. Taken together, these findings suggest that the alternative complement pathway plays a role in SSc-PAH pathogenesis and may serve as a biomarker to inform diagnosis and prognosis.

The Complement System as a Part of Immunometabolic Post-Exercise Response in Adipose and Muscle Tissue

The precise molecular processes underlying the complement's activation, which follows exposure to physical stress still remain to be fully elucidated. However, some possible mechanisms could play a role in initiating changes in the complement's activity, which are observed post-exposure to physical stress stimuli. These are mainly based on metabolic shifts that occur in the microenvironment of muscle tissue while performing its function with increased intensity, as well as the adipose tissue's role in sterile inflammation and adipokine secretion. This review aims to discuss the current opinions on the possible link between the complement activation and diet, age, sex, and health disorders with a particular emphasis on endocrinopathies and, furthermore, the type of physical activity and overall physical fitness. It has been indicated that regular physical activity incorporated into therapeutic strategies potentially improves the management of particular diseases, such as, e.g., autoimmune conditions. Moreover, it represents a favorable influence on immunoaging processes. A better understanding of the complement system's interaction with physical activity will support established clinical therapies targeting complement components.

Role of complement factor D in cardiovascular and metabolic diseases

In the genesis and progression of cardiovascular and metabolic diseases (CVMDs), adipose tissue plays a pivotal and dual role. Complement factor D (CFD, also known as adipsin), which is mainly produced by adipocytes, is the rate-limiting enzyme of the alternative pathway. Abnormalities in CFD generation or function lead to aberrant immune responses and energy metabolism. A large number of studies have revealed that CFD is associated with CVMDs. Herein, we will review the current studies on the function and mechanism of CFD in CVMDs such as hypertension, coronary heart disease, ischemia/reperfusion injury, heart failure, arrhythmia, aortic aneurysm, obesity, insulin resistance, and diabetic cardiomyopathy.

Proteomic Correlates and Prognostic Significance of Kidney Injury in Heart Failure With Preserved Ejection Fraction

BACKGROUND

Kidney disease is common in heart failure with preserved ejection fraction (HFpEF). However, the biologic correlates and prognostic significance of kidney injury (KI), in HFpEF, beyond the estimated glomerular filtration rate (eGFR), are unclear.

METHODS AND RESULTS

Using baseline plasma samples from the TOPCAT (Treatment of Preserved Cardiac Function Heart Failure With an Aldosterone Antagonist) trial, we measured the following KI biomarkers: cystatin-C, fatty acid-binding protein-3, Beta-2 microglobulin, neutrophil gelatinase-associated lipocalin, and kidney-injury molecule-1. Factor analysis was used to extract the common variability underlying these biomarkers. We assessed the relationship between the KI-factor score and the risk of death or HF-related hospital admission in models adjusted for the Meta-Analysis Global Group in Chronic Heart Failure risk score and eGFR. We also assessed the relationship between the KI factor score and ~5000 plasma proteins, followed by pathway analysis. We validated our findings among HFpEF participants in the Penn Heart Failure Study. KI was associated with the risk of death or HF-related hospital admission independent of the Meta-Analysis Global Group in Chronic Heart Failure risk score and eGFR. Both the risk score and eGFR were no longer associated with death or HF-related hospital admission after adjusting for the KI factor score. KI was predominantly associated with proteins and biologic pathways related to complement activation, inflammation, fibrosis, and cholesterol homeostasis. KI was associated with 140 proteins, which reproduced across cohorts. Findings regarding biologic associations and the prognostic significance of KI were also reproduced in the validation cohort.

CONCLUSIONS

KI is associated with adverse outcomes in HFpEF independent of baseline eGFR. Patients with HFpEF and KI exhibit a plasma proteomic signature indicative of complement activation, inflammation, fibrosis, and impaired cholesterol homeostasis.

A robust cis-Mendelian randomization method with application to drug target discovery

Mendelian randomization (MR) uses genetic variants as instrumental variables (IVs) to investigate causal relationships between traits. Unlike conventional MR, cis-MR focuses on a single genomic region using only cis-SNPs. For example, using cis-pQTLs for a protein as exposure for a disease opens a cost-effective path for drug target discovery. However, few methods effectively handle pleiotropy and linkage disequilibrium (LD) of cis-SNPs. Here, we propose cisMR-cML, a method based on constrained maximum likelihood, robust to IV assumption violations with strong theoretical support. We further clarify the severe but largely neglected consequences of the current practice of modeling marginal, instead of conditional genetic effects, and only using exposure-associated SNPs in cis-MR analysis. Numerical studies demonstrated our method's superiority over other existing methods. In a drug-target analysis for coronary artery disease (CAD), including a proteome-wide application, we identified three potential drug targets, PCSK9, COLEC11 and FGFR1 for CAD.

The Relationship between the complement system and subclinical carotid atherosclerosis in patients with rheumatoid arthritis

BACKGROUND

Patients with rheumatoid arthritis (RA) have an increased risk of cardiovascular (CV) events and CV mortality. Subclinical carotid atherosclerosis is independently associated with rates of incident CV events among patients with RA. The complement system has been related to both the etiopathogenesis of RA and CV disease. In this study, we aimed to evaluate the association between a comprehensive assessment of the complement system and carotid intima media thickness and carotid plaque in patients with RA.

METHODS

430 patients with RA were recruited. Functional assays of the three pathways of the complement system, utilizing new-generation techniques, were assessed. Additionally, serum levels of individual components of the complement system belonging to the three pathways were measured: C1q (classical), lectin (lectin), C2, C4, and C4b (classical and lectin), factor D and properdin (alternative), C3 and C3a (common), C5, C5a, and C9 (terminal), as well as regulators factor I and C1-inhibitor. Subclinical carotid atherosclerosis was evaluated by ultrasonography. Multivariable linear regression analysis was conducted to investigate the association between the complement system and carotid intima media thickness and carotid plaque.

RESULTS

After multivariable adjustment, which included traditional CV risk factors and disease-related data, C3a and C5a exhibited significant positive correlations with carotid intima media thickness. Additionally, higher values of C1-inhibitor, properdin, C3, C5, and C5a were independently associated with the presence of carotid plaque.

CONCLUSION

The complement system and subclinical carotid atherosclerosis are linked in patients with RA.

Diagnostic and prognostic value of plasma miR-106a-5p levels in patients with acute heart failure

BACKGROUND

It is essential to find reliable biomarkers for early diagnosis and prognosis of acute heart failure (AHF) for its mitigation. Currently, increasing attention is paid to the role of microRNAs (miRNAs/miRs) as diagnostic or prognostic markers for cardiovascular diseases. Since plasma miR-106a-5p has been observed to be downregulated in AHF, its value in the diagnosis and prognostic assessment of AHF deserves further exploration. Accordingly, this study analyzed the diagnostic and prognostic value of plasma miR-106a-5p in AHF patients.

METHODS

Prospectively, this study included 127 AHF patients who met the 2021 European Society of Cardiology Guidelines and 127 control individuals. Plasma miR-106a-5p levels were determined with RT-qPCR. Spearman correlation analysis was performed to evaluate the correlation of plasma miR-106a-5p levels with NT-proBNP and hs-CRP levels in AHF patients. All AHF patients were followed up for 1 year and allocated into poor and good prognosis groups, and plasma miR-106a-5p levels were compared. The diagnostic and prognostic value of plasma miR-106a-5p for AHF was assessed with a receiver-operating characteristic curve.

RESULTS

Plasma miR-106a-5p was lowly expressed in AHF patients versus controls (0.53 ± 0.26 vs. 1.09 ± 0.46) and showed significant negative correlations with NT-proBNP and hs-CRP levels. Plasma miR-106a-5p level < 0.655 could assist in AHF diagnosis. Plasma miR-106a-5p levels were markedly lower in poor-prognosis AHF patients than in good-prognosis patients. Plasma miR-106a-5p level < 0.544 could assist in predicting poor prognosis in AHF patients.

CONCLUSION

Plasma miR-106a-5p is downregulated in AHF patients and could assist in diagnosis and poor prognosis prediction of AHF.

Adipsin in the pathogenesis of cardiovascular diseases

Adipsin is an adipokine predominantly synthesized in adipose tissues and released into circulation. It is also known as complement factor-D (CFD), acting as the rate-limiting factor in the alternative complement pathway and exerting essential functions on the activation of complement system. The deficiency of CFD in humans is a very rare condition. However, complement overactivation has been implicated in the etiology of numerous disorders, including cardiovascular disease (CVD). Increased circulating level of adipsin has been reported to promote vascular derangements, systemic inflammation, and endothelial dysfunction. Prospective and case-control studies showed that this adipokine is directly associated with all-cause death and rehospitalization in patients with coronary artery disease. Adipsin has also been implicated in pulmonary arterial hypertension, abdominal aortic aneurysm, pre-eclampsia, and type-2 diabetes which is a major risk factor for CVD. Importantly, serum adipsin has been recognized as a unique prognostic marker for assessing cardiovascular diseases. At present, there is paucity of experimental evidence about the precise role of adipsin in the etiology of CVD. However, this mini review provides some insight on the contribution of adipsin in the pathogenesis of CVD and highlights its role on endothelial, smooth muscle and immune cells that mediate cardiovascular functions.

Serum proteomic identification and validation of two novel atherosclerotic aortic aneurysm biomarkers, profilin 1 and complement factor D

BACKGROUND

Effective diagnostic biomarkers for aortic aneurysm (AA) that are detectable in blood tests are required because early detection and rupture risk assessment of AA can provide insights into medical therapy and preventive treatments. However, known biomarkers for AA lack specificity and reliability for clinical diagnosis.

METHODS

We performed proteome analysis of serum samples from patients with atherosclerotic thoracic AA (TAA) and healthy control (HC) subjects to identify diagnostic biomarkers for AA. Serum samples were separated into low-density lipoprotein, high-density lipoprotein, and protein fractions, and the major proteins were depleted. From the proteins identified in the three fractions, we narrowed down biomarker candidates to proteins uniformly altered in all fractions between patients with TAA and HC subjects and evaluated their capability to discriminate patients with TAA and those with abdominal AA (AAA) from HC subjects using receiver operating characteristic (ROC) analysis. For the clinical validation, serum concentrations of biomarker candidates were measured in patients with TAA and AAA registered in the biobank of the same institute, and their capability for the diagnosis was evaluated.

RESULTS

Profilin 1 (PFN1) and complement factor D (CFD) showed the most contrasting profiles in all three fractions between patients with TAA and HC subjects and were selected as biomarker candidates. The PFN1 concentration decreased, whereas the CFD concentration increased in the sera of patients with TAA and AAA when compared with those of HC subjects. The ROC analysis showed that these proteins could discriminate patients with TAA and AAA from HC subjects. In the validation study, these candidates showed significant concentration differences between patients with TAA or AAA and controls. PFN1 and CFD showed sufficient area under the curve (AUC) in the ROC analysis, and their combination further increased the AUC. The serum concentrations of PFN1 and CFD also showed significant differences between patients with aortic dissection and controls in the validation study.

CONCLUSION

PFN1 and CFD are potential diagnostic biomarkers for TAA and AAA and measurable in blood samples; their diagnostic performance can be augmented by their combination. These biomarkers may facilitate the development of diagnostic systems to identify patients with AA.

Altered acylcarnitine metabolism and inflexible mitochondrial fuel utilization characterize the loss of neonatal myocardial regeneration capacity

Myocardial regeneration capacity declines during the first week after birth, and this decline is linked to adaptation to oxidative metabolism. Utilizing this regenerative window, we characterized the metabolic changes in myocardial injury in 1-day-old regeneration-competent and 7-day-old regeneration-compromised mice. The mice were either sham-operated or received left anterior descending coronary artery ligation to induce myocardial infarction (MI) and acute ischemic heart failure. Myocardial samples were collected 21 days after operations for metabolomic, transcriptomic and proteomic analyses. Phenotypic characterizations were carried out using echocardiography, histology and mitochondrial structural and functional assessments. In both groups, MI induced an early decline in cardiac function that persisted in the regeneration-compromised mice over time. By integrating the findings from metabolomic, transcriptomic and proteomic examinations, we linked regeneration failure to the accumulation of long-chain acylcarnitines and insufficient metabolic capacity for fatty acid beta-oxidation. Decreased expression of the redox-sensitive mitochondrial Slc25a20 carnitine-acylcarnitine translocase together with a decreased reduced:oxidized glutathione ratio in the myocardium in the regeneration-compromised mice pointed to a defect in the redox-sensitive acylcarnitine transport to the mitochondrial matrix. Rather than a forced shift from the preferred adult myocardial oxidative fuel source, our results suggest the facilitation of mitochondrial fatty acid transport and improvement of the beta-oxidation pathway as a means to overcome the metabolic barrier for repair and regeneration in adult mammals after MI and heart failure.

Complement factors B, D, C3bBbP and risk of future venous thromboembolism

The complement system appears to be involved in the pathogenesis of venous thromboembolism (VTE). We investigated the association of complement factors (CF) B, D, and the alternative pathway convertase, C3bBbP, measured at inclusion, with the risk of future VTE in a nested case-control study; 380 VTE patients and 804 age- and sex-matched controls derived from the Tromsø study. Odds ratios (ORs) with 95% confidence intervals (95% CI) for VTE across tertiles of CF concentrations were estimated using logistic regression. There was no association between CFB or CFD and risk of future VTE. Higher levels of C3bBbP gave an increased risk of provoked VTE; subjects in Q4 had a 1.68-fold higher OR compared with Q1 in the age-, sex- and BMI-adjusted model (OR 1.68; 95% CI 1.08-2.64). There was no increased risk of future VTE in individuals with higher levels of complement factors B or D of the alternative pathway. Increased levels of the alternative pathway activation product, C3bBbP, showed an association with future risk of provoked VTE.

Contribution of animal models to the mechanistic understanding of Alternative Pathway and Amplification Loop (AP/AL)-driven Complement-mediated Diseases

This review aimed to capture the key findings that animal models have provided around the role of the alternative pathway and amplification loop (AP/AL) in disease. Animal models, particularly mouse models, have been incredibly useful to define the role of complement and the alternative pathway in health and disease; for instance, the use of cobra venom factor and depletion of C3 provided the initial insight that complement was essential to generate an appropriate adaptive immune response. The development of knockout mice have further underlined the importance of the AP/AL in disease, with the FH knockout mouse paving the way for the first anti-complement drugs. The impact from the development of FB, properdin, and C3 knockout mice closely follows this in terms of mechanistic understanding in disease. Indeed, our current understanding that complement plays a role in most conditions at one level or another is rooted in many of these in vivo studies. That C3, in particular, has roles beyond the obvious in innate and adaptive immunity, normal physiology, and cellular functions, with or without other recognized AP components, we would argue, only extends the reach of this arm of the complement system. Humanized mouse models also continue to play their part. Here, we argue that the animal models developed over the last few decades have truly helped define the role of the AP/AL in disease.

The role of properdin and Factor H in disease

The complement system consists of three pathways (alternative, classical, and lectin) that play a fundamental role in immunity and homeostasis. The multifunctional role of the complement system includes direct lysis of pathogens, tagging pathogens for phagocytosis, promotion of inflammatory responses to control infection, regulation of adaptive cellular immune responses, and removal of apoptotic/dead cells and immune complexes from circulation. A tight regulation of the complement system is essential to avoid unwanted complement-mediated damage to the host. This regulation is ensured by a set of proteins called complement regulatory proteins. Deficiencies or malfunction of these regulatory proteins may lead to pro-thrombotic hematological diseases, renal and ocular diseases, and autoimmune diseases, among others. This review focuses on the importance of two complement regulatory proteins of the alternative pathway, Factor H and properdin, and their role in human diseases with an emphasis on: (a) characterizing the main mechanism of action of Factor H and properdin in regulating the complement system and protecting the host from complement-mediated attack, (b) describing the dysregulation of the alternative pathway as a result of deficiencies, or mutations, in Factor H and properdin, (c) outlining the clinical findings, management and treatment of diseases associated with mutations and deficiencies in Factor H, and (d) defining the unwanted and inadequate functioning of properdin in disease, through a discussion of various experimental research findings utilizing in vitro, mouse and human models.

Transcriptomic and Lipidomic Mapping of Macrophages in the Hub of Chronic Beta-Adrenergic-Stimulation Unravels Hypertrophy-, Proliferation-, and Lipid Metabolism-Related Genes as Novel Potential Markers of Early Hypertrophy or Heart Failure

Sympathetic nervous system overdrive with chronic release of catecholamines is the most important neurohormonal mechanism activated to maintain cardiac output in response to heart stress. Beta-adrenergic signaling behaves first as a compensatory pathway improving cardiac contractility and maladaptive remodeling but becomes dysfunctional leading to pathological hypertrophy and heart failure (HF). Cardiac remodeling is a complex inflammatory syndrome where macrophages play a determinant role. This study aimed at characterizing the temporal transcriptomic evolution of cardiac macrophages in mice subjected to beta-adrenergic-stimulation using RNA sequencing. Owing to a comprehensive bibliographic analysis and complementary lipidomic experiments, this study deciphers typical gene profiles in early compensated hypertrophy (ECH) versus late dilated remodeling related to HF. We uncover cardiac hypertrophy- and proliferation-related transcription programs typical of ECH or HF macrophages and identify lipid metabolism-associated and Na⁺ or K⁺ channel-related genes as markers of ECH and HF macrophages, respectively. In addition, our results substantiate the key time-dependent role of inflammatory, metabolic, and functional gene regulation in macrophages during beta-adrenergic dependent remodeling. This study provides important and novel knowledge to better understand the prevalent key role of resident macrophages in response to chronically activated beta-adrenergic signaling, an effective diagnostic and therapeutic target in failing hearts.

Multi-omics of human plasma reveals molecular features of dysregulated inflammation and accelerated aging in schizophrenia

Schizophrenia is a devastating psychiatric illness that detrimentally affects a significant portion of the worldwide population. Aging of schizophrenia patients is associated with reduced longevity, but the potential biological factors associated with aging in this population have not yet been investigated in a global manner. To address this gap in knowledge, the present study assesses proteomics and metabolomics profiles in the plasma of subjects afflicted with schizophrenia compared to non-psychiatric control patients over six decades of life. Global, unbiased analyses of circulating blood plasma can provide knowledge of prominently dysregulated molecular pathways and their association with schizophrenia, as well as features of aging and gender in this disease. The resulting data compiled in this study represent a compendium of molecular changes associated with schizophrenia over the human lifetime. Supporting the clinical finding of schizophrenia's association with more rapid aging, both schizophrenia diagnosis and age significantly influenced the plasma proteome in subjects assayed. Schizophrenia was broadly associated with prominent dysregulation of inflammatory and metabolic system components. Proteome changes demonstrated increased abundance of biomarkers for risk of physiologic comorbidities of schizophrenia, especially in younger individuals. These findings advance our understanding of the molecular etiology of schizophrenia and its associated comorbidities throughout the aging process.

The Alternative Complement Pathway Is Activated Without a Corresponding Terminal Pathway Activation in Patients With Heart Failure

Objective

Dysregulation of the complement system has been described in patients with heart failure (HF). However, data on the alternative pathway are scarce and it is unknown if levels of factor B (FB) and the C3 convertase C3bBbP are elevated in these patients. We hypothesized that plasma levels of FB and C3bBbP would be associated with disease severity and survival in patients with HF.

Methods

We analyzed plasma levels of FB, C3bBbP, and terminal C5b-9 complement complex (TCC) in 343 HF patients and 27 healthy controls.

Results

Compared with controls, patients with HF had elevated levels of circulating FB (1.6-fold, p < 0.001) and C3bBbP (1.3-fold, p < 0.001). In contrast, TCC, reflecting the terminal pathway, was not significantly increased (p = 0.15 vs controls). FB was associated with NT-proBNP, troponin, eGFR, and i.e., C-reactive protein. FB, C3bBbP and TCC were not associated with mortality in HF during a mean follow up of 4.3 years.

Conclusion

Our findings suggest that in patients with HF, the alternative pathway is activated. However, this is not accompanied by activation of the terminal pathway.

Inverse Association of Serum Adipsin with the Remission of Nonalcoholic Fatty-Liver Disease: A 3-Year Community-Based Cohort Study

PURPOSES

Adipokine alterations contribute to the development and remission of nonalcoholic fatty-liver disease (NAFLD). Adipsin is one of the most abundant adipokines and is almost exclusively produced by adipocytes. However, data on adipsin in human NAFLD are limited and controversial. We performed this study to investigate the association between adipsin and the remission of NAFLD in middle-aged and elderly Chinese adults.

METHODS

Whether adipsin is associated with the remission of NAFLD in a 3-year community-based prospective cohort study was investigated. Baseline levels of adipsin were measured in serum samples collected from 908 NAFLD participants. NAFLD was diagnosed using abdominal ultrasonography. Logistic regression analysis and a multiple stepwise logistic regression model including different variables were conducted to evaluate the association between serum adipsin levels and the remission of NAFLD.

RESULTS

During a mean follow-up of 3.14 ± 0.36 years, 247 (27.20%) participants with NAFLD at baseline were in remission. At baseline, serum adipsin concentration was positively correlated with body mass index (r: 0.39, p < 0.001), insulin (r: 0.31, p < 0.001), and homeostasis model assessment of insulin resistance (r: 0.31, p < 0.001) and was inversely associated with NAFLD remission with a fully adjusted odds ratio (OR) of 0.28 (0.16-0.48) (p trend < 0.001). In a multiple stepwise logistic regression model, circulating adipsin independently predicted NAFLD remission (OR: 0.284, 95% confidence interval [CI]: 0.172-0.471, p for trend <0.001). The area under the receiver operating characteristic curve was 0.751 (95% CI: 0.717-0.785) (p < 0.001) for the prediction model of NAFLD remission.

CONCLUSIONS

We provide evidence for an association between serum adipsin levels and the remission of NAFLD in a community-based prospective cohort study. Serum adipsin can be a potential biomarker for predicting NAFLD remission.

Novel lncRNA-miRNA-mRNA Competing Endogenous RNA Triple Networks Associated Programmed Cell Death in Heart Failure

Objective: Increasing evidence has uncovered the roles of lncRNA-miRNA-mRNA regulatory networks in cardiovascular diseases. However, the crosstalk between ceRNA networks and development of heart failure (HF) remains unclear. This study was to investigate the role of lncRNA-mediated ceRNA networks in the pathophysiological process of HF and its potential regulatory functions on programmed cell death.

Methods: We firstly screened the GSE77399, GSE52601 and GSE57338 datasets in the NCBI GEO database for screening differentially expressed lncRNAs, miRNAs and mRNAs. lncRNA-miRNA-mRNA regulatory networks based on the ceRNA theory were subsequently constructed. GO and KEGG enrichment analysis was conducted to predict potential biological functions of mRNAs in ceRNA networks. Differentially expressed mRNAs were then interacted with programmed cell death related genes. lncRNA-mediated ceRNA regulatory pathways on programmed cell death were validated with qRT-PCR testing.

Results: Based on our bioinformatic analysis, two lncRNAs, eight miRNAs and 65 mRNAs were extracted to construct two lncRNAs-mediated ceRNA networks in HF. Biological processes and pathways were enriched in extracellular matrix. Seven lncRNA-mediated ceRNA regulatory pathways on programmed cell death, GAS5/miR-345-5p/ADAMTS4, GAS5/miR-18b-5p/AQP3, GAS5/miR-18b-5p/SHISA3, GAS5/miR-18b-5p/C1orf105, GAS5/miR-18b-5p/PLIN2, GAS5/miR-185-5p/LPCAT3, and GAS5/miR-29b-3p/STAT3, were finally validated.

Conclusions: Two novel ceRNA regulatory networks in HF were discovered based on our bioinformatic analysis. Based on the interaction and validation analysis, seven lncRNA GAS5-mediated ceRNA regulatory pathways were hypothesized to impact programmed cell death including seven for apoptosis, three for ferroptosis, and one for pyroptosis. Upon which, we provided novel insights and potential research plots for bridging ceRNA regulatory networks and programmed cell death in HF.

Lactate Dehydrogenase B and Pyruvate Oxidation Pathway Associated With Carfilzomib-Related Cardiotoxicity in Multiple Myeloma Patients: Result of a Multi-Omics Integrative Analysis

Multiple myeloma (MM) is the second most frequent hematologic cancer in the United States. Carfilzomib (CFZ), an irreversible proteasome inhibitor being used to treat relapsed and refractory MM, has been associated with cardiotoxicity, including heart failure. We hypothesized that a multi-omics approach integrating data from different omics would provide insights into the mechanisms of CFZ-related cardiovascular adverse events (CVAEs). Plasma samples were collected from 13 MM patients treated with CFZ (including 7 with CVAEs and 6 with no CVAEs) at the University of Florida Health Cancer Center. These samples were evaluated in global metabolomic profiling, global proteomic profiling, and microRNA (miRNA) profiling. Integrative pathway analysis was performed to identify genes and pathways differentially expressed between patients with and without CVAEs. The proteomics analysis identified the up-regulation of lactate dehydrogenase B (LDHB) [fold change (FC) = 8.2, p = 0.01] in patients who experienced CVAEs. The metabolomics analysis identified lower plasma abundance of pyruvate (FC = 0.16, p = 0.0004) and higher abundance of lactate (FC = 2.4, p = 0.0001) in patients with CVAEs. Differential expression analysis of miRNAs profiling identified mir-146b to be up-regulatein (FC = 14, p = 0.046) in patients with CVAE. Pathway analysis suggested that the pyruvate fermentation to lactate pathway is associated with CFZ-CVAEs. In this pilot multi-omics integrative analysis, we observed the down-regulation of pyruvate and up-regulation of LDHB among patients who experienced CVAEs, suggesting the importance of the pyruvate oxidation pathway associated with mitochondrial dysfunction. Validation and further investigation in a larger independent cohort are warranted to better understand the mechanisms of CFZ-CVAEs.

Postconditioning attenuates myocardial ischemia-reperfusion injury by inhibiting complement activation and upregulation of miR-499

The complement system plays a vital role in myocardial ischemia/reperfusion (I/R) injury. microRNA (miR)-499 is involved in the cardioprotection of ischemic postconditioning (IPostC). The present study aimed to study the role of the complement system and miR-499 in IPostC. Rat hearts were subjected to coronary ligation for 30 min, followed by reperfusion for 2 h. IPostC was introduced at the onset of reperfusion with three cycles of reperfusion for 30 sec and coronary artery occlusion for 30 sec. To study the role of miR-499 in IPostC, adeno-associated virus (AAV) vectors of miR-499-5p (AAV-miR-499-5p) and miR-499-5p-sponge (AAV-miR-499-5p-sponge) were transfected via tail vein injection, followed by IPostC protocols. Cardiac injury as well as the status of local and systemic complement activation and inflammation were assessed. IPostC significantly attenuated I/R-induced rat cardiomyocyte apoptosis and the myocardial infarct size. These beneficial effects were accompanied by decreased local and circulating complement component (C)3a and C5a levels, decreased inflammatory marker expression, decreased NF-κB signaling and increased cardiac miR-499 expression. AAV-miR-499-5p prevented local and systemic complement activation and inflammation as well as enhanced the cardioprotection of IPostC, whereas AAV-miR-499-5p-sponge produced the opposite effects. In summary, IPostC protected the rat myocardium against I/R injury, by inhibiting local and systemic complement activation; inflammation; NF-κB signaling; and upregulation of miR-499. As such, miR-499 may have a critical role in IPostC-mediated cardioprotection against I/R injury.

Alternative Pathway Involvement in Protoporphyria Patients Related to Sun Exposure

The homeostasis of tissues in a chronic disease is an essential function of the alternative pathway (AP) of the complement system (CS). However, if not controlled, it may also be detrimental to healthy cells with a consequent aggravation of symptoms. The protoporphyria (PP) is a rare chronic disease that causes phototoxicity in visible light with local skin pain and general malaise. In order to establish if there is a systemic involvement of the CS during sun exposure, we designed a non-invasive method with a serum collection in winter and summer from 19 PP and 13 controls to detect the levels of CS protein: Properdin, Factor H (FH), and C5. Moreover, the global radiation data were collected from the regional agency of environmental protection (ARPA). The results show growing values for every protein in patients with PP, compared to control, in both seasons, in particular in summer compared to winter. To reinforce the evidence, we have estimated the personal exposure of patients based on the global radiation data. The main factors of the AP increased over the season, confirming the involvement of the AP in relation to light exposure. The systemic response could justify the general malaise of patients after long light exposure and can be exploited to elucidate new therapeutic approaches.

Plasma proteoglycan prolargin in diagnosis and differentiation of pulmonary arterial hypertension

Aims

Right ventricular dysfunction may arise because of pulmonary arterial hypertension (PAH). Development of new diagnostic methods able to identify PAH and allow for earlier treatment initiation, before the development of vascular remodelling and manifest right heart failure (HF), could potentially improve prognosis. Proteoglycans and inflammatory proteins are involved in vascular remodelling. We aimed to investigate their potential as biomarkers to differentiate PAH in a dyspnoeic population.

Methods and results

Plasma from 152 patients with PAH (n = 48), chronic thrombo‐embolic pulmonary hypertension (n = 20), pulmonary hypertension due to HF with reduced (n = 36) or preserved (n = 33) ejection fraction, and HF without pulmonary hypertension (n = 15) and 20 healthy controls were analysed with proximity extension assays. Haemodynamics were assessed in the patients with right heart catheterization. Plasma prolargin levels in PAH were lower compared with all the other studied disease groups (P < 0.001) but higher than the controls' levels (P = 0.003). Receiver operating characteristic curve of prolargin as a PAH‐differentiating marker in a pooled population, encompassing all the other studied disease groups, had a sensitivity of 74% and a specificity of 83.3% (area under the curve = 0.84, P < 0.001). Prolargin correlated with the mean right atrial pressure (r_s = 0.65, P < 0.001), N‐terminal pro‐brain natriuretic peptide (r_s = 0.64, P < 0.001), cardiac index (r_s = −0.31, P = 0.029), stroke volume index (r_s = −0.41, P = 0.004), right ventricular stroke work index (r_s = −0.31, P = 0.032), six‐minute walking distance (r_s = −0.41, P = 0.005), and mixed venous blood oxygen saturation (r_s = −0.42, P = 0.003).

Conclusions

Plasma prolargin levels differentiate PAH patients from controls and the other investigated dyspnoea groups including HF. Its potential in PAH differentiation may be enhanced by inclusion in a multi‐marker panel. Larger studies are needed to evaluate its discriminative ability of PAH in relation to other dyspnoea aetiologies and its potential role in PAH risk stratification and pathobiology.

Increased Alternative Complement Pathway Function and Improved Survival during Critical Illness

Rationale: Complement is crucial for host defense but may also drive dysregulated inflammation. There is limited understanding of alternative complement function, which can amplify all complement activity, during critical illness.Objectives: We examined the function and key components of the alternative complement pathway in a series of critically ill patients and in a mouse pneumonia model.Methods: Total classical (CH50) and alternative complement (AH50) function were quantified in serum from 321 prospectively enrolled critically ill patients and compared with clinical outcomes. Alternative pathway (AP) regulatory factors were quantified by ELISA (n = 181) and examined via transcriptomics data from external cohorts. Wild-type, Cfb-/-, and C3-/- mice were infected intratracheally with Klebsiella pneumoniae (KP) and assessed for extrapulmonary dissemination.Measurements and Main Results: AH50 greater than or equal to median, but not CH50 greater than or equal to median, was associated with decreased 30-day mortality (adjusted odds ratio [OR], 0.53 [95% confidence interval (CI), 0.31-0.91]), independent of chronic liver disease. One-year survival was improved in patients with AH50 greater than or equal to median (adjusted hazard ratio = 0.59 [95% CI, 0.41-0.87]). Patients with elevated AH50 had increased levels of AP factors B, H, and properdin, and fewer showed a "hyperinflammatory" subphenotype (OR, 0.30 [95% CI, 0.18-0.49]). Increased expression of proximal AP genes was associated with improved survival in two external cohorts. AH50 greater than or equal to median was associated with fewer bloodstream infections (OR, 0.67 [95% CI, 0.45-0.98). Conversely, depletion of AP factors, or AH50 less than median, impaired in vitro serum control of KP that was restored by adding healthy serum. Cfb-/- mice demonstrated increased extrapulmonary dissemination and serum inflammatory markers after intratracheal KP infection compared with wild type.Conclusions: Elevated AP function is associated with improved survival during critical illness, possibly because of enhanced immune capacity.

The role of B cells in heart failure and implications for future immunomodulatory treatment strategies

Despite numerous demonstrations that the immune system is activated in heart failure, negatively affecting patients' outcomes, no definitive treatment strategy exists directed to modulate the immune system. In this review, we present the evidence that B cells contribute to the development of hypertrophy, inflammation, and maladaptive tissue remodelling. B cells produce antibodies that interfere with cardiomyocyte function, which culminates as the result of recruitment and activation of a variety of innate and structural cell populations, including neutrophils, macrophages, fibroblasts, and T cells. As B cells appear as active players in heart failure, we propose here novel immunomodulatory therapeutic strategies that target B cells and their products.

Reappraising the role of inflammation in heart failure

The observation that heart failure with reduced ejection fraction is associated with elevated circulating levels of pro-inflammatory cytokines opened a new area of research that has revealed a potentially important role for the immune system in the pathogenesis of heart failure. However, until the publication in 2019 of the CANTOS trial findings on heart failure outcomes, all attempts to target inflammation in the heart failure setting in phase III clinical trials resulted in neutral effects or worsening of clinical outcomes. This lack of positive results in turn prompted questions on whether inflammation is a cause or consequence of heart failure. This Review summarizes the latest developments in our understanding of the role of the innate and adaptive immune systems in the pathogenesis of heart failure, and highlights the results of phase III clinical trials of therapies targeting inflammatory processes in the heart failure setting, such as anti-inflammatory and immunomodulatory strategies. The most recent of these studies, the CANTOS trial, raises the exciting possibility that, in the foreseeable future, we might be able to identify those patients with heart failure who have a cardio-inflammatory phenotype and will thus benefit from therapies targeting inflammation.

Complement Components sC5b-9 and CH50 Predict Prognosis in Heart Failure Patients Combined With Hypertension

BACKGROUND

Heart failure (HF), resulting from inflammation and vessel injury, is one of the leading causes of poor quality of life and premature death. The complement system plays a leading role in vessel integrity and inflammation response. However, the association between serum complement level and the prognosis of HF remains unclear.

METHODS

In our study, a total of 263 newly diagnosed hypertension patients with HF were included. Eight classical cardiovascular risk factors were collected, and plasma C3a, C3b, C5a, sC5b-9, and CH50 levels were detected.

RESULTS

Compared with the control group, plasma C5a (P<0.001), sC5b-9 (P<0.001), and CH50 (P = 0.004) levels of hypertension patients with HF were significantly increased. On the basis of univariate analysis, an older age, higher frequency of alcohol consumption, high level of body mass index, medium or high risk of hypertension, hyperlipidemia, and diabetes were poor prognostic factors whereas low levels of C5a, sC5b-9, and CH50 were associated with favorable overall survival (OS). When these factors fit into a multivariate regression model, patients with hyperlipidemia (P = 0.002, hazard ratio [HR] = 3.09), N-terminal pro-Brain Natriuretic Peptide (NT-pro-BNP) ≥ 14.8 (P < 0.001, HR = 11.14), sC5b-9 level ≥ 1,406.2 µg/ml (P = 0.180, HR = 5.51) or CH50 level ≥ 294.6 µg/ml (P < 0.001, HR = 4.57) remained statistically factors for worsened OS and regarded as independent risk factors. These independently associated risk factors were used to form an OS estimation nomogram. Nomogram demonstrated good accuracy in estimating the risk, with a bootstrap-corrected C index of 0.789.

CONCLUSIONS

sC5b-9 and CH50 levels are increased in hypertension patients with HF. Nomogram based on multivariate analysis has good accuracy in estimating the risk of OS.

Associations of High-Sensitivity Cardiac Troponin and Natriuretic Peptide With Subsequent Risk of Infection in Persons Without Cardiovascular Disease: The Atherosclerosis Risk in Communities Study

Whether persons without prevalent cardiovascular disease (CVD) but elevated levels of high-sensitivity cardiac troponin T (hs-cTnT) or N-terminal pro-B-type natriuretic peptide (NT-proBNP) are at high risk of infection is unknown. Using 1996-2013 data from the Atherosclerosis Risk in Communities Study, we estimated hazard ratios for incident hospitalization with infection in relation to plasma hs-cTnT and NT-proBNP concentrations among participants without prevalent CVD and contrasted them with hazard ratios for persons with prevalent CVD (coronary heart disease, heart failure, or stroke). In a multivariable Cox model, prevalent CVD was significantly associated with risk of hospitalization with infection (hazard ratio (HR) = 1.31, 95% confidence interval (CI): 1.19, 1.45). Among participants without prevalent CVD, hs-cTnT and NT-proBNP were independently associated with infection risk in a graded fashion (e.g., HR = 1.44 (95% CI: 1.24, 1.69) for hs-cTnT ≥14 ng/L and HR = 1.28 (95% CI: 1.14, 1.44) for hs-cTnT 9-13 ng/L vs. <3 ng/L; HR = 1.57 (95% CI: 1.35, 1.81) for NT-proBNP ≥248.1 pg/mL and HR = 1.19 (95% CI: 1.06, 1.34) for NT-proBNP 137.2-248.0 pg/mL vs. <48.1 pg/mL). The 15-year cumulative incidences of hospitalization with infection were similar for participants with prevalent CVD and participants who did not have prevalent CVD but had hs-cTnT ≥14 ng/L or NT-proBNP ≥248.1 pg/mL. Thus, hs-cTnT and NT-proBNP were independently associated with infection risk. Persons without CVD but with elevated hs-cTnT or NT-proBNP levels should be recognized to have similar infection risks as persons with prevalent CVD.

Profiling of the plasma proteome across different stages of human heart failure

Heart failure (HF) is a major public health problem characterized by inability of the heart to maintain sufficient output of blood. The systematic characterization of circulating proteins across different stages of HF may provide pathophysiological insights and identify therapeutic targets. Here we report application of aptamer-based proteomics to identify proteins associated with prospective HF incidence in a population-based cohort, implicating modulation of immunological, complement, coagulation, natriuretic and matrix remodeling pathways up to two decades prior to overt disease onset. We observe further divergence of these proteins from the general population in advanced HF, and regression after heart transplantation. By leveraging coronary sinus samples and transcriptomic tools, we describe likely cardiac and specific cellular origins for several of the proteins, including Nt-proBNP, thrombospondin-2, interleukin-18 receptor, gelsolin, and activated C5. Our findings provide a broad perspective on both cardiac and systemic factors associated with HF development.

The role of the complement factor B-arginase-polyamine molecular axis in uremia-induced cardiac remodeling in mice

The role of complement system in heart diseases is controversial. Besides, the mechanisms by which complement components participate in cardiac remodeling (CR) and heart failure during uremia are unclear. In this study, 5/6 nephrectomy was performed to adult mice to establish the uremic model and CR deteriorated over the course of uremia. Although complement pathways were not further activated over the course of the disease, soluble complement factor B (CFB) was upregulated at post-nephrectomy day 90 (PNx90) compared with PNx30. Further, CFB notably deteriorated CR in uremic mice but this effect was reversed by depletion of macrophages with liposomal clodronate. In vivo and in vitro CFB upregulated arginase 1 (ARG1) expression, increased ARG1 enzymatic activity, and stimulated the syntheses of ornithine, leading to polyamine overproduction in macrophages. Putrescine, an important polyamine, promoted cardiac fibroblast proliferation and collagen production, resulting in progressive CR. In vivo the inhibition of ARG1 activity with N^ω -hydroxyl-l-arginine remarkably improved the general survival rates, inhibited the infiltration of cardiac fibroblasts, and alleviated progression of CR in uremic mice. Taken together, the CFB-ARG1-putrescine axis is related to progression of CR and ARG1 hyperactivity in macrophages may provide a novel therapeutic target against the heart injury in uremia.

Heart disease in a mutant mouse model of spontaneous eosinophilic myocarditis maps to three loci

Background

Heart disease (HD) is the major cause of morbidity and mortality in patients with hypereosinophilic diseases. Due to a lack of adequate animal models, our understanding of the pathophysiology of eosinophil-mediated diseases with heart complications is limited. We have discovered a mouse mutant, now maintained on an A/J inbred background, that spontaneously develops hypereosinophilia in multiple organs. Cellular infiltration into the heart causes an eosinophilic myocarditis, with affected mice of the mutant line (i.e., A/J^HD) demonstrating extensive myocardial damage and remodeling that leads to HD and premature death, usually by 15-weeks old.

Results

Maintaining the A/J^HD line for many generations established that the HD trait was heritable and implied the mode of inheritance was not too complex. Backcross and intercross populations generated from mating A/J^HD males with females from four different inbred strains produced recombinant populations with highly variable rates of affected offspring, ranging from none in C57BL/6 J intercrosses, to a few mice with HD using 129S1/SvImJ intercrosses and C57BL/6 J backcrosses, but nearly 8% of intercrosses and > 17% of backcrosses from SJL/J related populations developed HD. Linkage analyses of these SJL/J derived recombinants identified three highly significant loci: a recessive locus mapping to distal chromosome 5 (LOD = 4.88; named Emhd1 for eosinophilic myocarditis to heart disease-1); and two dominant variants mapping to chromosome 17, one (Emhd2; LOD = 7.51) proximal to the major histocompatibility complex, and a second (Emhd3; LOD = 6.89) that includes the major histocompatibility region. Haplotype analysis identified the specific crossovers that defined the Emhd1 (2.65 Mb), Emhd2 (8.46 Mb) and Emhd3 (14.59 Mb) intervals.

Conclusions

These results indicate the HD trait in this mutant mouse model of eosinophilic myocarditis is oligogenic with variable penetrance, due to multiple segregating variants and possibly additional genetic or nongenetic factors. The A/J^HD mouse model represents a unique and valuable resource to understand the interplay of causal factors that underlie the pathology of this newly discovered eosinophil-associated disease with cardiac complications.

Increased Complement Factor B and Bb Levels Are Associated with Mortality in Patients with Severe Aortic Stenosis

Inflammation is involved in initiation and progression of aortic stenosis (AS). However, the role of the complement system, a crucial component of innate immunity in AS, is unclear. We hypothesized that circulating levels of complement factor B (FB), an important component of the alternative pathway, are upregulated and could predict outcome in patients with severe symptomatic AS. Therefore, plasma levels of FB, Bb, and terminal complement complex were analyzed in three cohorts of patients with severe symptomatic AS and mild-to-moderate or severe asymptomatic AS (population 1, n = 123; population 2, n = 436; population 3, n = 61) and in healthy controls by enzyme immunoassays. Compared with controls, symptomatic AS patients had significantly elevated levels of FB (2.9- and 2.8-fold increase in population 1 and 2, respectively). FB levels in symptomatic and asymptomatic AS patients were comparable (population 2 and 3), and in asymptomatic patients FB correlated inversely with valve area. FB levels in population 1 and 2 correlated with terminal complement complex levels and measures of systemic inflammation (i.e., CRP), cardiac function (i.e., NT-proBNP), and cardiac necrosis (i.e., Troponin T). High FB levels were significantly associated with mortality also after adjusting for clinical and biochemical covariates (hazard ratio 1.37; p = 0.028, population 2). Plasma levels of the Bb fragment showed a similar pattern in relation to mortality. We concluded that elevated levels of FB and Bb are associated with adverse outcome in patients with symptomatic AS. Increased levels of FB in asymptomatic patients suggest the involvement of FB from the early phase of the disease.

The role of properdin in complement-mediated renal diseases: a new player in complement-inhibiting therapy?

Properdin is known as the only positive regulator of the complement system. Properdin promotes the activity of this defense system by stabilizing its key enzymatic complexes: the complement alternative pathway (AP) convertases. Besides, some studies have indicated a role for properdin as an initiator of complement activity. Though the AP is a powerful activation route of the complement system, it is also involved in a wide variety of autoimmune and inflammatory diseases, many of which affect the kidneys. The role of properdin in regulating complement in health and disease has not received as much appraisal as the many negative AP regulators, such as factor H. Historically, properdin deficiency has been strongly associated with an increased risk for meningococcal disease. Yet only recently had studies begun to link properdin to other complement-related diseases, including renal diseases. In the light of the upcoming complement-inhibiting therapies, it is interesting whether properdin can be a therapeutic target to attenuate AP-mediated injury. A full understanding of the basic concepts of properdin biology is therefore needed. Here, we first provide an overview of the function of properdin in health and disease. Then, we explore its potential as a therapeutic target for the AP-associated renal diseases C3 glomerulopathy, atypical hemolytic uremic syndrome, and proteinuria-induced tubulointerstitial injury. Considering current knowledge, properdin-inhibiting therapy seems promising in certain cases. However, knowing the complexity of properdin's role in renal pathologies in vivo, further research is required to clarify the exact potential of properdin-targeted therapy in complement-mediated renal diseases.

Association of ficolin-2 (FCN2) functional polymorphisms and protein levels with rheumatic fever and rheumatic heart disease: relationship with cardiac function

Introduction

A role for ficolin (FCN) 2 gene polymorphisms in the pathogenesis of recurrent severe streptococcal infections and rheumatic carditis has been suggested. The aim of the study was to evaluate a possible relationship between single nucleotide polymorphisms located at positions -602 and -4 of the FCN2 gene and FCN2 serum levels and risk of development of rheumatic fever (RF) and rheumatic heart disease (RHD).

Material and methods

Seventy-seven Caucasian Egyptian patients with RF were recruited with a control group of 43 healthy subjects. DNA was extracted for analysis of the FCN2 gene at positions -602 and -4 and serum protein level was measured by ELISA.

Results

FCN2 AA genotype at the -4 position was more frequently observed in RF and RHD patients, as compared to healthy subjects (p = 0.005 and p = 0.013, respectively); furthermore, the A allele was identified as a possible risk factor for the development of RF (p = 0.023, OR = 1.852, 95% CI: 1.085–3.159). The haplotype –602/–4 G/A, which was associated with low median levels of L-ficolin, was observed more frequently in the RF group when compared to the healthy subjects (74/162, 48.1% vs. 29/420, 33.7%, OR = 1.834, 95% CI: 1.034–3.252, p = 0.038). Low serum ficolin-2 level was associated with ESV and EDV increases. FCN 2 level was significantly lower with AA genotypes than GG+AG genotypes of the -4 position (56.68 ±17.90 vs. 66.05 ±18.79, p = 0.008).

Conclusions

Polymorphisms linked to low levels of L-ficolin may render an individual at risk of recurrent and/or severe streptococcal infection. The -4 AA genotype and -602/-4 G/A haplotype are possible risk factors for the development of carditis.

Properdin: A multifaceted molecule involved in inflammation and diseases

Properdin, the widely known positive regulator of the alternative pathway (AP), has undergone significant investigation over the last decade to define its function in inflammation and disease, including its role in arthritis, asthma, and kidney and cardiovascular diseases. Properdin is a glycoprotein found in plasma that is mainly produced by leukocytes and can positively regulate AP activity by stabilizing C3 and C5 convertases and initiating the AP. Promotion of complement activity by properdin results in changes in the cellular microenvironment that contribute to innate and adaptive immune responses, including pro-inflammatory cytokine production, immune cell infiltration, antigen presenting cell maturation, and tissue damage. The use of properdin-deficient mouse models and neutralizing antibodies has contributed to the understanding of the mechanisms by which properdin contributes to promoting or preventing disease pathology. This review mainly focusses on the multifaceted roles of properdin in inflammation and diseases, and how understanding these roles is contributing to the development of new disease therapies.