Ferritin levels and risk of heart failure-the Atherosclerosis Risk in Communities Study

Genetically predicted biomarkers of iron homeostasis and risk of non-ischemic cardiomyopathy: A mendelian randomization study

BACKGROUND AND AIMS

Both iron overload and iron deficiency have been associated with cardiovascular diseases in observational studies. Previous Mendelian Randomization (MR) studies discovered a protective effect of higher iron status on coronary atrial disease, while a neutral effect on all-cause heart failure. Using two-sample MR, we evaluated how genetically predicted systemic iron status affects the risk of non-ischemic cardiomyopathy and different phenotypes.

METHODS AND RESULTS

Two-sample MR analyses were performed to estimate the causal effect of four biomarkers of systemic iron status on diagnosed cardiomyopathy and its subtypes in 242,607 participants from the FinnGen research project. The level of transferrin saturation was significantly associated with an increased risk of cardiomyopathy (OR, 1.17; 95% CI, 1.13-1.38) when using nine separately selected genetic instruments. An increase in genetically determined serum iron (odds ratio [OR] per standard deviation [SD], 1.25; 95% confidence interval [CI], 1.13-1.38) and ferritin (OR, 1.49; 95% CI, 1.02-2.18) were associated with an increased risk of cardiomyopathy. Total iron binding capacity, a marker of reduced iron status, was inversely linked with cardiomyopathy (OR, 0.80; 95% CI, 0.65-0.98). The risk effect of iron status was more evident in hypertrophic cardiomyopathy and related heart failure.

CONCLUSIONS

These analyses support the causal effect of increased systemic iron status on a higher risk of non-ischemic cardiomyopathy. A screening test for cardiomyopathy should be considered in patients with evidence of iron overload. Future study is needed for exploring the mechanism of these causal variants on cardiomyopathy.

Analysis of mechanism, therapeutic strategies, and potential natural compounds against atherosclerosis by targeting iron overload-induced oxidative stress

Ferroptosis is a novel form of cell demise characterized primarily by the reduction of trivalent iron to divalent iron, leading to the release of reactive oxygen species (ROS) and consequent induction of intense oxidative stress. In atherosclerosis (AS), highly accumulated lipids are modified by ROS to promote the formation of lipid peroxides, further amplifying cellular oxidative stress damage to influence all stages of atherosclerotic development. Macrophages are regarded as pivotal executors in the progression of AS and the handling of iron, thus targeting macrophage iron metabolism holds significant guiding implications for exploring potential therapeutic strategies against AS. In this comprehensive review, we elucidate the potential interplay among iron overload, inflammation, and lipid dysregulation, summarizing the potential mechanisms underlying the suppression of AS by alleviating iron overload. Furthermore, the application of Traditional Chinese Medicine (TCM) is increasingly widespread. Based on extant research and the pharmacological foundations of active compounds of TCM, we propose alternative therapeutic agents for AS in the context of iron overload, aiming to diversify the therapeutic avenues.

Metabolic Derangement of Essential Transition Metals and Potential Antioxidant Therapies

Essential transition metals have key roles in oxygen transport, neurotransmitter synthesis, nucleic acid repair, cellular structure maintenance and stability, oxidative phosphorylation, and metabolism. The balance between metal deficiency and excess is typically ensured by several extracellular and intracellular mechanisms involved in uptake, distribution, and excretion. However, provoked by either intrinsic or extrinsic factors, excess iron, zinc, copper, or manganese can lead to cellular damage upon chronic or acute exposure, frequently attributed to oxidative stress. Intracellularly, mitochondria are the organelles that require the tightest control concerning reactive oxygen species production, which inevitably leaves them to be one of the most vulnerable targets of metal toxicity. Current therapies to counteract metal overload are focused on chelators, which often cause secondary effects decreasing patients' quality of life. New therapeutic options based on synthetic or natural antioxidants have proven positive effects against metal intoxication. In this review, we briefly address the cellular metabolism of transition metals, consequences of their overload, and current therapies, followed by their potential role in inducing oxidative stress and remedies thereof.

A Population-Based and Clinical Cohort Validation of the Novel Consensus Definition of Metabolic Hyperferritinemia

CONTEXT

There is limited data on the clinical significance of metabolic hyperferritinemia (MHF) based on the most recent consensus.

OBJECTIVE

We aimed to validate the clinical outcomes of MHF in the general population and patients with biopsy-proven metabolic dysfunction-associated fatty liver disease (MAFLD).

METHODS

The NHANES database and PERSONS cohort were included. MHF was defined as elevated serum ferritin with metabolic dysfunction (MD) and stratified into different grades according to ferritin (grade 1: 200 [females]/300 [males]-550 ng/mL; grade 2: 550-1000 ng/mL; grade 3: >1000 ng/mL). The clinical outcomes, including all-cause death, comorbidities, and liver histology, were compared between non-MHF and MHF in adjusted models.

RESULTS

In NHANES, compared with non-MHF with MD, MHF was related to higher risks of advanced fibrosis (P = .036), elevated albumin-creatinine ratio (UACR, P = .001), and sarcopenia (P = .013). Although the association between all grades of MHF and mortality was insignificant (P = .122), grades 2/3 was associated with increased mortality (P = .029). When comparing with non-MHF without MD, the harmful effects of MHF were more significant in mortality (P < .001), elevated UACR (P < .001), cardiovascular disease (P = .028), and sarcopenia (P < .001). In the PERSONS cohort, MHF was associated with more advanced grades of steatosis (P < .001), lobular inflammation (P < .001), advanced fibrosis (P = .017), and more severe hepatocellular iron deposition (P < .001).

CONCLUSION

Both in the general population and in at-risk individuals with MAFLD, MHF was related with poorer clinical outcomes.

Emerging regulatory mechanisms in cardiovascular disease: Ferroptosis

Ferroptosis, distinct from apoptosis, necrosis, autophagy, and other types of cell death, is a novel iron-dependent regulated cell death characterized by the accumulation of lipid peroxides and redox imbalance with distinct morphological, biochemical, and genetic features. Dysregulation of iron homeostasis, the disruption of antioxidative stress pathways and lipid peroxidation are crucial in ferroptosis. Ferroptosis is involved in the pathogenesis of several cardiovascular diseases, including atherosclerosis, cardiomyopathy, myocardial infarction, ischemia-reperfusion injury, abdominal aortic aneurysm, aortic dissection, and heart failure. Therefore, a comprehensive understanding of the mechanisms that regulate ferroptosis in cardiovascular diseases will enhance the prevention and treatment of these diseases. This review discusses the latest findings on the molecular mechanisms of ferroptosis and its regulation in cardiovascular diseases, the application of ferroptosis modulators in cardiovascular diseases, and the role of traditional Chinese medicines in ferroptosis regulation to provide a comprehensive understanding of the pathogenesis of cardiovascular diseases and identify new prevention and treatment options.

Iron Status and Risk of Heart Disease, Stroke, and Diabetes: A Mendelian Randomization Study in European Adults

BACKGROUND

The relevance of iron status biomarkers for coronary artery disease (CAD), heart failure (HF), ischemic stroke (IS), and type 2 diabetes (T2D) is uncertain. We compared the observational and Mendelian randomization (MR) analyses of iron status biomarkers and hemoglobin with these diseases.

METHODS AND RESULTS

Observational analyses of hemoglobin were compared with genetically predicted hemoglobin with cardiovascular diseases and diabetes in the UK Biobank. Iron biomarkers included transferrin saturation, serum iron, ferritin, and total iron binding capacity. MR analyses assessed associations with CAD (CARDIOGRAMplusC4D [Coronary Artery Disease Genome Wide Replication and Meta-Analysis Plus The Coronary Artery Disease Genetics], n=181 522 cases), HF (HERMES [Heart Failure Molecular Epidemiology for Therapeutic Targets), n=115 150 cases), IS (GIGASTROKE, n=62 100 cases), and T2D (DIAMANTE [Diabetes Meta-Analysis of Trans-Ethnic Association Studies], n=80 154 cases) genome-wide consortia. Observational analyses demonstrated J-shaped associations of hemoglobin with CAD, HF, IS, and T2D. In contrast, MR analyses demonstrated linear positive associations of higher genetically predicted hemoglobin levels with 8% higher risk per 1 SD higher hemoglobin for CAD, 10% to 13% for diabetes, but not with IS or HF in UK Biobank. Bidirectional MR analyses confirmed the causal relevance of iron biomarkers for hemoglobin. Further MR analyses in global consortia demonstrated modest protective effects of iron biomarkers for CAD (7%-14% lower risk for 1 SD higher levels of iron biomarkers), adverse effects for T2D, but no associations with IS or HF.

CONCLUSIONS

Higher levels of iron biomarkers were protective for CAD, had adverse effects on T2D, but had no effects on IS or HF. Randomized trials are now required to assess effects of iron supplements on risk of CAD in high-risk older people.

Plasma Ferritin Levels, Incident Heart Failure, and Cardiac Structure and Function: The ARIC Study

BACKGROUND

Whether iron deficiency contributes to incident heart failure (HF) and cardiac dysfunction has important implications given the prevalence of iron deficiency and the availability of several therapeutics for iron repletion.

OBJECTIVES

The aim of this study was to estimate the associations of plasma ferritin level with incident HF overall, HF phenotypes, and cardiac structure and function measures in older adults.

METHODS

Participants in the ongoing, longitudinal ARIC (Atherosclerosis Risk In Communities) study who were free of prevalent HF and anemia were studied. The associations of plasma ferritin levels with incident HF overall and heart failure with preserved ejection fraction (HFpEF) and heart failure with reduced ejection fraction (HFrEF) were estimated using Cox proportional hazards regression models. Linear regression models estimated the cross-sectional associations of plasma ferritin with echocardiographic measures of cardiac structure and function.

RESULTS

The cohort included 3,472 individuals with a mean age of 75 ± 5 years (56% women, 14% Black individuals). In fully adjusted models, lower ferritin was associated with higher risk for incident HF overall (HR: 1.20 [95% CI: 1.08-1.34] per 50% lower ferritin level) and higher risk for incident HFpEF (HR: 1.28 [95% CI: 1.09-1.50]). Associations with incident HFrEF were not statistically significant. Lower ferritin levels were associated with higher E/e' ratio and higher pulmonary artery systolic pressure after adjustment for demographics and HF risk factors but not with measures of left ventricular structure or systolic function.

CONCLUSIONS

Among older adults without prevalent HF or anemia, lower plasma ferritin level is associated with a higher risk for incident HF, HFpEF, and higher measures of left ventricular filling pressure.

A Comprehensive Review on Serum Ferritin as a Prognostic Marker in Intensive Care Units: Insights Into Ischemic Heart Disease

Serum ferritin has garnered considerable attention as a prognostic marker in intensive care units (ICUs), offering valuable insights into patient outcomes and clinical management strategies. This comprehensive review examines the role of serum ferritin in predicting outcomes among critically ill patients, with a particular focus on its implications for ischemic heart disease (IHD). Elevated serum ferritin levels have consistently been associated with adverse outcomes in ICU settings, including increased mortality, prolonged hospital stays, and higher morbidity rates. Furthermore, the relationship between serum ferritin levels and IHD underscores its potential as a biomarker for cardiovascular risk assessment in critically ill populations. The review synthesizes existing literature to highlight the predictive value of serum ferritin in assessing illness severity and guiding clinical decision-making in the ICUs. It also explores potential mechanisms linking serum ferritin to adverse outcomes and discusses implications for clinical practice. Integrating serum ferritin measurements into routine assessments could enhance prognostication and risk stratification in ICU patients, while further research is needed to elucidate optimal management strategies and therapeutic targets. Collaborative efforts between clinicians and researchers are essential to advance our understanding of serum ferritin's prognostic value in the ICUs and translate this knowledge into improved patient care and outcomes.

Serum ferritin as a significant biomarker for patients with idiopathic inflammatory myopathy-associated interstitial lung disease: A systematic review and meta-analysis

OBJECTIVE

The biomarkers for predicting the occurrence, progression, and death of idiopathic inflammatory myopathy-associated interstitial lung disease (IIM-ILD) remain unclear. Serum ferritin (SF) is a potential candidate and this systematic review and meta-analysis aimed to reveal the clinical significance of SF in IIM-ILD.

METHODS

Eligible English studies were selected from PubMed, Embase, Web of science and Scopus up to 9 June 2023. The SF levels in patients with IIM-ILD were extracted and pooled. Subgroup analysis was performed based on disease types, sensitivity analysis was conducted by excluding one class of literature at a time, and publication bias was assessed by funnel plot and Egger's test.

RESULTS

Pooled analysis of 1,933 patients with IIM from 19 studies showed that SF levels were significantly higher in IIM-ILD group (WMD=263.53ng/mL, 95% CI: 146.44-380.62, p<0.001) than IIM without ILD, subgroup analysis showed that SF levels in DM-ILD (WMD = 397.67ng/mL, 95% CI:142.84-652.50, p = 0.002) and PM/DM-ILD (WMD = 117.68 ng/mL, 95% CI: 86.32-149.04, p < 0.001) were significantly higher compared to those without ILD. SF levels were significantly higher in rapidly progressive interstitial lung disease group (RP-ILD)(WMD = 484.99 ng/mL, 95% CI: 211.12-758.87, p= 0.001) than chronic ILD(C-ILD) group, subgroup analysis showed that SF levels in DM-RP-ILD (WMD= 509.75 ng/mL, 95% CI: 215.34-804.16, p=0.001) were significantly higher than those in DM-C-ILD group. SF levels were significantly higher in death group (WMD= 722.16 ng/mL, 95% CI: 572.32-872.00, p< 0.001) compared to the survival group, subgroup analysis showed that death patients with DM-ILD(WMD= 735.62 ng/mL, 95% CI:574.92-896.32, p<0.001) and PM-ILD (WMD= 632.56 ng/mL, 95% CI:217.92-1047.19, p=0.003) had significantly higher SF levels than survival group respectively.

CONCLUSION

Increased SF levels can serve as a biomarker for predicting the occurrence, progression and death of patients with IIM-ILD, which can provide early warning sign for intervention and prognosis evaluation for IIM-ILD patients.

Interaction between systemic iron parameters and left ventricular structure and function in the preserved ejection fraction population: a two-sample bidirectional Mendelian randomization study

BACKGROUND

Left ventricular (LV) remodeling and diastolic function in people with heart failure (HF) are correlated with iron status; however, the causality is uncertain. This Mendelian randomization (MR) study investigated the bidirectional causal relationship between systemic iron parameters and LV structure and function in a preserved ejection fraction population.

METHODS

Transferrin saturation (TSAT), total iron binding capacity (TIBC), and serum iron and ferritin levels were extracted as instrumental variables for iron parameters from meta-analyses of public genome-wide association studies. Individuals without myocardial infarction history, HF, or LV ejection fraction (LVEF) < 50% (n = 16,923) in the UK Biobank Cardiovascular Magnetic Resonance Imaging Study constituted the outcome dataset. The dataset included LV end-diastolic volume, LV end-systolic volume, LV mass (LVM), and LVM-to-end-diastolic volume ratio (LVMVR). We used a two-sample bidirectional MR study with inverse variance weighting (IVW) as the primary analysis method and estimation methods using different algorithms to improve the robustness of the results.

RESULTS

In the IVW analysis, one standard deviation (SD) increased in TSAT significantly correlated with decreased LVMVR (β = -0.1365; 95% confidence interval [CI]: -0.2092 to -0.0638; P = 0.0002) after Bonferroni adjustment. Conversely, no significant relationships were observed between other iron and LV parameters. After Bonferroni correction, reverse MR analysis showed that one SD increase in LVEF significantly correlated with decreased TSAT (β = -0.0699; 95% CI: -0.1087 to -0.0311; P = 0.0004). No heterogeneity or pleiotropic effects evidence was observed in the analysis.

CONCLUSIONS

We demonstrated a causal relationship between TSAT and LV remodeling and function in a preserved ejection fraction population.

Association between Serum Ferritin and Prognosis in Patients with Ischemic Heart Disease in Intensive Care Units

PURPOSE

Recent years have seen a clear link established between elevated ferritin levels and COVID-19 prognosis. However, the impact of heightened ferritin levels on the prognosis of individuals with severe ischemic heart disease remains uncertain.

METHODS

We utilized the MIMIC IV database to identify a cohort of ischemic heart disease patients who underwent serum ferritin testing. We conducted regression analyses, employed the overlap propensity score weighting model, and utilized the restricted cubic splines model to comprehensively investigate the associations between serum ferritin levels and clinical outcomes.

RESULTS

Our cohort included 1173 patients with diagnosed ischemic heart disease, categorized into high and low serum ferritin groups. After meticulous adjustment for confounding factors in a fully adjusted model, the hazard ratios (HRs) for 90-day and 1-year mortality were 1.63 (95% CI: 1.27-2.09) and 1.49 (95% CI: 1.19-1.86), respectively, in the high-ferritin group compared to the low-ferritin group. Subsequent analyses with propensity score weighting confirmed these results. Remarkably, restricted cubic spline analysis revealed an almost linear relationship between log-transformed serum ferritin levels and the risk of both 90-day and 1-year all-cause mortality. Moreover, incorporating ferritin into conventional severity of illness scores significantly improved the area under the curve for both 90-day and 1-year mortality.

CONCLUSIONS

This study provides compelling evidence regarding the prognostic significance of serum ferritin in predicting 90-day and one-year mortality rates among patients diagnosed with ischemic heart disease.

Serum ferritin and the risk of short-term mortality in critically ill patients with chronic heart failure: a retrospective cohort study

Background: Serum ferritin levels are associated with a higher risk of incident heart failure (HF). Whether serum ferritin levels, either increased or decreased, predict the risk of mortality in individuals with chronic heart failure (CHF) remains unknown. Objectives: This study aimed to clarify the potential predictive significance of serum ferritin levels in assessing the short-term mortality in critically ill patients with chronic heart failure (CHF). Methods: Critically ill patients with CHF were identified from the Multiparameter Intelligent Monitoring in Intensive Care III and IV (MIMIC III and IV) databases. Linear and logistic regression models and Cox proportional hazards models were applied to assess the associations between serum ferritin and survival. Results: A total of 1,739 and 2,322 patients with CHF identified from the MIMIC III and IV databases, respectively, fulfilled the inclusion criteria. In the MIMIC III group, compared with the reference group (serum ferritin ≥70 and <500 ng/mL), serum ferritin ≥1000 ng/mL was a significant predictor of 28-day (odds ratio [OR], 1.76; 95% confidence interval [CI], 1.14-2.72) and 90-day mortality (OR, 1.64; 95% CI, 1.13-2.39). The results from the Cox regression and Kaplan-Meier curves revealed similar results. In the MIMIC IV group, serum ferritin ≥1000 ng/mL was a significant predictor of in-hospital (OR, 1.70; 95% CI, 1.18-2.46), 28-day (OR, 1.83; 95% CI, 1.24-2.69), and 90-day mortality (OR, 1.57; 95% CI, 1.11-2.22) after adjusting for confounding factors. Conclusion: High ferritin levels (≥1000 ng/mL) were associated with increased short-term mortality in critically ill patients with CHF, indicating that serum ferritin may serve as a useful prognostic marker for CHF.

GADD34 activates p53 and may have utility as a marker of atherosclerosis

We previously identified growth arrest and DNA-damage-inducible gene 34 (GADD34) as a marker of ischemic stroke. In the present study, serum levels of anti-GADD34 antibodies were found to be significantly higher in patients with acute ischemic stroke or chronic kidney disease compared to healthy donors. We then examined the biological function of GADD34 by transfection into U2OS human osteosarcoma and U87 human glioblastoma cells. Knockdown of GADD34 by siRNA resulted in enhanced cell proliferation, which was reversed by co-knockdown of MDM2. Luciferase reporter assays revealed that the transactivation ability of p53 enhanced by genotoxic anticancer drugs such as camptothecin and etoposide was further potentiated by enforced expression of GADD34 but attenuated by co-transfection with p53 shRNA expression plasmids. Western blotting demonstrated increased p53 protein levels after treatment with camptothecin, which was also potentiated by GADD34 but suppressed by GADD34 siRNA, ATM siRNA, and ATM inhibitor wortmannin. GADD34 levels also increased in response to treatment with camptothecin or adriamycin, and this increase was attenuated by MDM2 siRNA. Immunoprecipitation with anti-GADD34 antibody followed by Western blotting with anti-MDM2 antibodies indicated ubiquitination of GADD34 is mediated by MDM2. Accordingly, GADD34 may function as a ubiquitination decoy to reduce p53 ubiquitination and increase p53 protein levels. Increased neuronal cell death due to activation of p53 by GADD34 may account for the elevated serum levels of anti-GADD34 antibodies observed in patients with acute ischemic stroke.

Inhibition of ferroptosis by icariin treatment attenuates excessive ethanol consumption-induced atrial remodeling and susceptibility to atrial fibrillation, role of SIRT1

Ferroptosis contributes to the pathogenesis of atrial fibrillation (AF), although the mechanisms are still largely uncovered. The current study was designed to explore the pharmacological effects of icariin against ethanol-induced atrial remodeling, if any, and the mechanisms involved with a focus on SIRT1 signaling. Excessive ethanol-treated animals were administered with Ferrostatin-1, Erastin or icariin to evaluate the potential effects of icariin or ferroptosis. Then, the underling mechanisms was further explored in the in vitro experiments using HL-1 atrial myocytes. Excessive ethanol administration caused significant atrial damage as evidenced by increased susceptibility to AF, altered atrial conduction pattern, atrial enlargement, and enhanced fibrotic markers. These detrimental effects were reversed by Ferrostatin-1 or icariin treatment, while Erastin co-administration markedly abolished the beneficial actions conferred by icariin. Mechanistically, ethanol-treated atria exhibited markedly up-regulated pro-ferroptotic protein (PTGS2, ACSL4, P53) and suppressed anti-ferroptotic molecules (GPX4, FTH1). Icariin treatment inhibited ethanol-induced atrial ferroptosis by reducing atrial mitochondrial damage, ROS accumulation and iron overload. Interestingly, the in vivo and in vitro data showed that icariin activated atrial SIRT1-Nrf-2-HO-1 signaling pathway, while EX527 not only reversed these effects, but also abolished the therapeutic effects of icariin. Moreover, the stimulatory effects on GPX4, SLC7A11 and the suppressive effects on ACSL4, P53 conferred by icariin were blunted by EX527 treatment. These data demonstrate that ferroptosis plays a causative role in the pathogenesis of ethanol-induced atrial remodeling and susceptibility to AF. Icariin protects against atrial damage by inhibiting ferroptosis via SIRT1 signaling. Its role as a prophylactic/therapeutic drug deserves further clinical study.

Iron homeostasis in the heart: Molecular mechanisms and pharmacological implications

Iron is necessary for the life of practically all living things, yet it may also harm people toxically. Accordingly, humans and other mammals have evolved an effective and tightly regulatory system to maintain iron homeostasis in healthy tissues, including the heart. Iron deficiency is common in patients with heart failure, and is associated with worse prognosis in this population; while the prevalence of iron overload-related cardiovascular disorders is also increasing. Therefore, enhancing the therapy of patients with cardiovascular disorders requires a thorough understanding of iron homeostasis. Here, we give readers an overview of the fundamental mechanisms governing systemic iron homeostasis as well as the most recent knowledge about the intake, storage, use, and export of iron from the heart. Genetic mouse models used for investigation of iron metabolism in various in vivo scenarios are summarized and highlighted. We also go through different clinical conditions and therapeutic approaches that target cardiac iron dyshomeostasis. Finally, we conclude the review by outlining the present knowledge gaps and important open questions in this field in order to guide future research on cardiac iron metabolism.

Sex and N-terminal pro B-type natriuretic peptide: The potential mediating role of iron biomarkers

BACKGROUND

Levels of N-terminal pro B-type natriuretic peptide (NT-proBNP), a marker of heart failure and cardiovascular risk, are generally higher in women than men. We explored whether iron biomarkers mediate sex differences in NT-proBNP levels.

METHODS

We included 5,343 community-dwelling individuals from the Prevention of Renal and Vascular Endstage Disease study. With linear regression analyses, we investigated the association of sex and iron biomarkers with NT-proBNP levels, independent of adjustment for potential confounders. The assessed iron biomarkers included ferritin, transferrin saturation (TSAT), hepcidin, and soluble transferrin receptor (sTfR). Next, we performed mediation analyses to investigate to which extent iron biomarkers influence the association between sex and NT-proBNP.

RESULTS

Of the included 5,343 participants, the mean standard deviation age was 52.2 ± 11.6 years and 52% were females. After adjustment for potential confounders, women compared to men, had higher NT-proBNP (β = 0.31; 95%CI = 0.29, 0.34), but lower ferritin (β = -0.37; 95%CI = -0.39, -0.35), hepcidin (β = -0.22, 95%CI = -0.24, -0.20), and TSAT (β = -0.07, 95% CI = -0.08, -0.06). Lower ferritin (β = -0.05, 95%CI = -0.08, -0.02), lower hepcidin (β = -0.04, 95%CI = -0.07, -0.006), and higher TSAT (β = 0.07; 95%CI = 0.01, 0.13) were associated with higher NT-proBNP. In mediation analyses, ferritin and hepcidin explained 6.5 and 3.1% of the association between sex and NT-proBNP, respectively, while TSAT minimally suppressed (1.9%) this association.

CONCLUSION

Our findings suggest that iron biomarkers marginally explain sex differences in levels of NT-proBNP. Future studies are needed to explore causality and potential mechanisms underlying these pathways.

Sex-Specific Association Between Iron Status and the Predicted 10-Year Risk for Atherosclerotic Cardiovascular Disease in Hypertensive Patients

Serum ferritin (SF) and haemoglobin (Hb) are widely used in clinical practice to assess iron status. Studies exploring the relationship of SF and Hb with atherosclerotic cardiovascular disease (ASCVD) risk have yielded conflicting results, and some indicated sex specificity. Hypertensive patients have abnormal iron status. However, research on patients with hypertension is limited. We aim to investigate the sex-specific links of SF and Hb with the predicted 10-year ASCVD risk in hypertensive patients. This cross-sectional study included 718 hypertensive men and 708 hypertensive women. The predicted 10-year ASCVD risk was calculated based on the China-PAR equation. The dose-response curves were illustrated by fitting linear and quadratic models. In hypertensive men, the iron status fits for a quadratic model for ASCVD risk, showing a U-shape. After adjusting for potential confounding factors, the regression coefficients and 95% confidence intervals (95% CI) across tertile of SF were 0.0 (reference), - 0.99 (- 1.65, - 0.33) and - 0.22 (- 0.88, 0.44), and of Hb were 0.0 (reference), - 0.74 (- 1.41, - 0.08) and - 0.77 (- 1.46, - 0.08). In hypertensive women, iron status was linearly and positively associated with ASCVD risk. Per one unit increment of log-transformed SF as well as Hb was associated with a 1.22 (95% CI: 0.97, 1.48) and 0.04 (95% CI: 0.02, 0.07) increased in ASCVD risk score, respectively. A significant interaction between iron status and inflammation on ASCVD risk was observed in hypertensive women. SF and Hb showed a U-shape with ASCVD risk in hypertensive men; however, a positive linear relationship was observed in hypertensive women.

Association between iron status and incident coronary artery disease: a population based-cohort study

Disorders of iron metabolism has been implicated in cardiovascular disease. However, the association of serum iron stores and coronary artery disease (CAD) remains inconsistent. Here, we investigated the associations of serum iron metabolism with the incidence of CAD, the severity of coronary artery stenosis, metabolic biomarkers, and the risk of major adverse cardiovascular event (MACE). A total of 643 CAD patients and 643 healthy controls were enrolled to assess the associations of serum iron status with the presence of CAD, the severity of CAD, and the risk of MACE. Serum iron metabolism and other metabolic markers were measured in all subjects. All statistical analyses were analyzed using SPSS22.0 software and STATA statistical package. Serum level of iron metabolism markers, including serum iron, unsaturated transferrin iron binding capacity (UIBC), Total iron binding capacity (TIBC) levels, in CAD groups was significantly lower than the control group (P < 0.001). UIBC and TIBC were negatively correlated with ferritin in both sexes. Each unit increase of serum iron and TIBC were found to have a protective role for CAD in women (iron: OR 0.794, 95% CI (0.647-0.973), TIBC: OR 0.891, 95% CI (0.795-0.999), P < 0.05). However, high ferritin level was significant associated the CAD incident in both sexes (OR 1.029, 95% CI (1.002-1.058) in men, OR 1.013, 95% CI (1.0-1.025) in women, P < 0.05). Serum iron metabolism markers exhibited no significant association with the severity of CAD. Increased serum level of iron and TIBC levels were found to have a protective role for CAD in women, but not in men. Elevated serum ferritin is independently and positively associated with CAD in men and women.

Appraising the Causal Association between Systemic Iron Status and Heart Failure Risk: A Mendelian Randomisation Study

Although observational studies have shown that abnormal systemic iron status is associated with an increased risk of heart failure (HF), it remains unclear whether this relationship represents true causality. We aimed to explore the causal relationship between iron status and HF risk. Two-sample Mendelian randomisation (MR) was applied to obtain a causal estimate. Genetic summary statistical data for the associations (p < 5 × 10−8) between single nucleotide polymorphisms (SNPs) and four iron status parameters were obtained from the Genetics of Iron Status Consortium in genome-wide association studies involving 48,972 subjects. Statistical data on the association of SNPs with HF were extracted from the UK biobank consortium (including 1088 HF cases and 360,106 controls). The results were further tested using MR based on the Bayesian model averaging (MR-BMA) and multivariate MR (MVMR). Of the twelve SNPs considered to be valid instrumental variables, three SNPs (rs1800562, rs855791, and rs1799945) were associated with all four iron biomarkers. Genetically predicted iron status biomarkers were not causally associated with HF risk (all p > 0.05). Sensitivity analysis did not show evidence of potential heterogeneity and horizontal pleiotropy. Convincing evidence to support a causal relationship between iron status and HF risk was not found. The strong relationship between abnormal iron status and HF risk may be explained by an indirect mechanism.

Expression of Iron Metabolism Proteins in Patients with Chronic Heart Failure

In heart failure, iron deficiency is a common comorbid disease that negatively influences exercise tolerance, number of hospitalizations and mortality rate, and this is why iron iv supplementation is recommended. Little is known about the changes in iron-related proteins in the human HF myocardium. The purpose of this study was to assess iron-related proteins in non-failing (NFH) vs. failing (FH) human myocardium. The study group consisted of 58 explanted FHs; control consisted of 31 NFHs unsuitable for transplantation. Myocardial proteins expressions: divalent metal transporter (DMT-1); L-type calcium channel (L-CH); transferrin receptors (TfR-1/TfR-2); ferritins: heavy (FT-H) or light (FT-L) chain, mitochondrial (FT-MT); ferroportin (FPN), regulatory factors and oxidative stress marker: 4-hydroxynonenal (4-HNE). In FH, the expression in almost all proteins responsible for iron transport: DMT-1, TfR-1, L-CH, except TfR-2, and storage: FT-H/-L/-MT were reduced, with no changes in FPN. Moreover, 4-HNE expression (pg/mg; NFH 10.6 ± 8.4 vs. FH 55.7 ± 33.7; p < 0.0001) in FH was increased. HNE-4 significantly correlated with DMT-1 (r = −0.377, p = 0.036), L-CH (r = −0.571, p = 0.001), FT-H (r = −0.379, p = 0.036), also FPN (r = 0.422, p = 0.018). Reducing iron-gathering proteins and elevated oxidative stress in failing hearts is very unfavorable for myocardiocytes. It should be taken into consideration before treatment with drugs or supplements that elevate free oxygen radicals in the heart.

Factors associated with serum ferritin levels and iron excess: results from the EPIC-EurGast study

PURPOSE

Excess iron is involved in the development of non-communicable diseases such as cancer, type 2 diabetes and cardiovascular conditions. We aimed to describe the prevalence of excess iron and its determinants in healthy European adults.

METHODS

Sociodemographic, lifestyle, iron status, dietary information, and HFE genotyping were obtained from controls from the nested case-control study EPIC-EurGast study. High sensitivity C-reactive protein (hsCRP) was measured to address possible systemic inflammation. Descriptive and multivariate analyses were used to assess iron status and its determinants.

RESULTS

Out of the 828 participants (median age: 58.7 years), 43% were females. Median serum ferritin and prevalence of excess iron were 143.7 µg/L and 35.2% in males, respectively, and 77 µg/L and 20% in females, both increasing with latitude across Europe. Prevalence of HFE C282Y mutation was significantly higher in Northern and Central Europe (~ 11%) than in the South (5%). Overweight/obesity, age, and daily alcohol and heme iron intake were independent determinants for iron status, with sex differences even after excluding participants with hsCRP > 5 mg/L. Obese males showed a greater consumption of alcohol, total and red meat, and heme iron, compared with those normal weight.

CONCLUSION

Obesity, higher alcohol and heme iron consumption were the main risk factors for excess iron in males while only age was associated with iron overload in females. Weight control and promoting healthy lifestyle may help prevent iron overload, especially in obese people. Further research is needed to clarify determinants of excess iron in the healthy adult population, helping to reduce the associated comorbidities.

Research Progress on Relationship Between Iron Overload and Lower Limb Arterial Disease in Type 2 Diabetes Mellitus

Iron is one of the most important trace elements in life activities. It participates in a variety of important physiological processes in the body through oxidation-reduction reaction. A large number of studies show that iron overload (IO) is closely related to the progression of diabetes and its various chronic complications. However, the mechanism of iron overload in the pathogenesis of diabetes and the mechanism of iron overload in atherosclerosis (AS) are still controversial, and the relationship between iron overload and diabetic lower extremity arterial disease (LEAD) remains still unclear. Some recent reviews and original research articles suggest further studies to explain the complex relationship between iron metabolism and atherosclerosis. This article reviews the relationship between iron overload and diabetes and its relationship with LEAD, and discusses its mechanisms from various aspects, such as lipid peroxidation induced by iron overload, so as to provide clinical diagnosis and treatment ideas for diabetic lower extremity arterial disease. It is hoped that early evaluation, diagnosis and treatment of LEAD will be inspired.

Malnutrition Increases the Risk of Left Ventricular Remodeling

OBJECTIVES

Malnutrition is associated with increased incidence of heart failure (HF). Left ventricular (LV) remodeling is one of the most important processes in the occurrence and evolution of HF. However, the association between nutritional status and LV remodeling is not well known. The study aimed to investigate the association between malnutrition and LV remodeling.

DESIGN

The study was a retrospective observation study.

SETTING AND PARTICIPANTS

We included patients from the registry of Cardiorenal Improvement study from January 2007 to December 2018 at Guangdong Provincial People's Hospital.

MEASUREMENTS

The primary endpoint was LV remodeling, defined as an absolute decrease in LV ejection fraction ≥10% after discharge compared with baseline. Nutritional status was assessed by the Controlling Nutritional Status (CONUT) score. Eligible patients were divided into absent-mild malnutrition group (CONUT score ≤4) and moderate-severe malnutrition group (CONUT score >4). Univariable and multivariable logistic regression was performed to verify the association between malnutrition and left ventricular remodeling.

RESULTS

A total of 7,217 patients (mean age 61.3±10.5 years, 71.7% male) were included in the final analysis, among which 712 (9.9%) had LV remodeling. The incidence of LV remodeling in moderate-severe malnutrition group was significantly higher than that in absent-mild malnutrition group (12.9% vs. 9.5%, p=0.002). In multivariable logistic regression, moderate-severe malnutrition group was significantly associated with 1.69-fold increased risk of LV remodeling after adjusting confounders (OR: 1.69, CI: 1.32-2.16). Similar results were observed in subgroup stratified by age, gender, and coronary artery disease.

CONCLUSION

Nearly one eighth of patients were classified as moderate-severe malnutrition, 12% of whom had LV remodeling. Moderate-severe malnutrition was associated with 69% increased risk of LV remodeling. Further studies are needed to prospectively evaluate the nutrition-oriented managements on outcomes in LV remodeling.

Triad role of hepcidin, ferroportin, and Nrf2 in cardiac iron metabolism: From health to disease

Iron is an essential trace element required for several vital physiological and developmental processes, including erythropoiesis, bone, and neuronal development. Iron metabolism and oxygen homeostasis are interlinked to perform a vital role in the functionality of the heart. The metabolic machinery of the heart utilizes almost 90 % of oxygen through the electron transport chain. To handle this tremendous level of oxygen, the iron metabolism in the heart is utmost crucial. Iron availability to the heart is therefore tightly regulated by (i) the hepcidin/ferroportin axis, which controls dietary iron absorption, storage, and recycling, and (ii) iron regulatory proteins 1 and 2 (IRP1/2) via hypoxia inducible factor 1 (HIF1) pathway. Despite iron being vital to the heart, recent investigations have demonstrated that iron imbalance is a common manifestation in conditions of heart failure (HF), since free iron readily transforms between Fe²⁺ and Fe³⁺via the Fenton reaction, leading to reactive oxygen species (ROS) production and oxidative damage. Therefore, to combat iron-mediated oxidative stress, targeting Nrf2/ARE antioxidant signaling is rational. The involvement of Nrf2 in regulating several genes engaged in heme synthesis, iron storage, and iron export is beginning to be uncovered. Consequently, it is possible that Nrf2/hepcidin/ferroportin might act as an epicenter connecting iron metabolism to redox alterations. However, the mechanism bridging the two remains obscure. In this review, we tried to summarize the contemporary insight of how cardiomyocytes regulate intracellular iron levels and discussed the mechanisms linking cardiac dysfunction with iron imbalance. Further, we emphasized the impact of Nrf2 on the interplay between systemic/cardiac iron control in the context of heart disease, particularly in myocardial ischemia and HF.

Iron Deficiency in Heart Failure: Mechanisms and Pathophysiology

Iron is an essential micronutrient for a myriad of physiological processes in the body beyond erythropoiesis. Iron deficiency (ID) is a common comorbidity in patients with heart failure (HF), with a prevalence reaching up to 59% even in non-anaemic patients. ID impairs exercise capacity, reduces the quality of life, increases hospitalisation rate and mortality risk regardless of anaemia. Intravenously correcting ID has emerged as a promising treatment in HF as it has been shown to alleviate symptoms, improve quality of life and exercise capacity and reduce hospitalisations. However, the pathophysiology of ID in HF remains poorly characterised. Recognition of ID in HF triggered more research with the aim to explain how correcting ID improves HF status as well as the underlying causes of ID in the first place. In the past few years, significant progress has been made in understanding iron homeostasis by characterising the role of the iron-regulating hormone hepcidin, the effects of ID on skeletal and cardiac myocytes, kidneys and the immune system. In this review, we summarise the current knowledge and recent advances in the pathophysiology of ID in heart failure, the deleterious systemic and cellular consequences of ID.

Biomarkers in the clinical management of patients with atrial fibrillation and heart failure

Atrial fibrillation (AF) and heart failure (HF) are two cardiovascular diseases with an increasing prevalence worldwide. These conditions share common pathophysiologiesand frequently co-exit. In fact, the occurrence of either condition can 'cause' the development of the other, creating a new patient group that demands different management strategies to that if they occur in isolation. Regardless of the temproral association of the two conditions, their presence is linked with adverse cardiovascular outcomes, increased rate of hospitalizations, and increased economic burden on healthcare systems. The use of low-cost, easily accessible and applicable biomarkers may hasten the correct diagnosis and the effective treatment of AF and HF. Both AF and HF effect multiple physiological pathways and thus a great number of biomarkers can be measured that potentially give the clinician important diagnostic and prognostic information. These will then guide patient centred therapeutic management. The current biomarkers that offer potential for guiding therapy, focus on the physiological pathways of miRNA, myocardial stretch and injury, oxidative stress, inflammation, fibrosis, coagulation and renal impairment. Each of these has different utility in current clinincal practice.

Maternal Iron Status in Early Pregnancy and Blood Pressure Throughout Pregnancy, Placental Hemodynamics, and the Risk of Gestational Hypertensive Disorders

BACKGROUND

In nonpregnant populations, higher serum ferritin, which reflects high iron stores, is associated with an increased risk of hypertension. We hypothesized that a dysregulated maternal iron status in early pregnancy may lead to impaired gestational hemodynamic adaptations, leading to an increased risk of gestational hypertensive disorders.

OBJECTIVES

We examined the associations of maternal iron status with maternal blood pressure, placental hemodynamic parameters, and the risks of gestational hypertensive disorders.

METHODS

In a population-based prospective cohort study among 5983 pregnant women, we measured maternal serum ferritin, transferrin saturation, serum iron, and transferrin concentrations at a median of 13.2 weeks gestation (95% range, 9.6-17.6). Maternal blood pressure was measured in early pregnancy, mid pregnancy, and late pregnancy, and placental hemodynamic parameters in mid pregnancy and late pregnancy were measured by ultrasound. Information on gestational hypertensive disorders was collected from medical records. We examined the associations of maternal early pregnancy iron status with maternal systolic and diastolic blood pressure, placental hemodynamic parameters, and the risks of gestational hypertensive disorders using linear and logistic regression models.

RESULTS

Higher maternal early pregnancy serum ferritin concentrations were associated with higher systolic and diastolic blood pressure throughout pregnancy in the basic models (P values < 0.05). After adjustment for maternal inflammation, sociodemographic and lifestyle factors, higher maternal early pregnancy serum ferritin concentrations were only associated with a higher early pregnancy diastolic blood pressure [0.27 (95% CI, 0.03-0.51) mmHg per SD score increase in serum ferritin] and with a higher mid pregnancy umbilical artery pulsatility index (P < 0.05). No associations with the risk of gestational hypertensive disorders were present.

CONCLUSIONS

No consistent associations were present of maternal iron status in early pregnancy with gestational hemodynamic adaptations or the risks of gestational hypertensive disorders. Further studies are needed to examine the potential role of iron metabolism in the development of gestational hypertensive disorders within higher-risk populations.

Iron deficiency and short-term adverse events in patients with decompensated heart failure

BACKGROUND

For patients with heart failure (HF), iron deficiency (ID) is a common therapeutic target. However, little is known about the utility of transferrin saturation (TSAT) or serum ferritin for risk stratification in decompensated HF (DHF) or the European Society of Cardiology's (ESC) current definition of ID (ferritin < 100 μg/L or TSAT < 20% if ferritin is 100-299 μg/L). We evaluated the association between these potential markers of ID and the risk of 30-day readmission for HF or death in patients with DHF.

METHODS

We retrospectively included 1701 patients from a multicenter registry of DHF. Serum ferritin and TSAT were evaluated 24-72 h after hospital admission, and multivariable Cox regression was used to assess their association with the composite endpoint.

RESULTS

Participants' median (quartiles) age was 76 (68-82) years, 43.8% were women, and 51.7% had a left ventricular ejection fraction > 50%. Medians for NT-proBNP, TSAT, and ferritin were 4067 pg/mL (1900-8764), 14.1% (9.0-20.3), and 103 ug/L (54-202), respectively. According to the current ESC definition, 1,246 (73.3%) patients had ID. By day 30, there were 177 (10.4%) events (95 deaths and 85 HF readmission). After multivariable adjustment, lower TSAT was associated with outcome (p = 0.009) but serum ferritin was not (HR 1.00; 95% confidence interval 0.99-1.00, p = 0.347).

CONCLUSIONS

Lower TSAT, but not ferritin, was associated with a higher risk of short-term events in patients with DHF. Further research is needed to confirm these findings and the utility of serum ferritin as a marker of ID in DHF.

Subclinical Heart Dysfunction in Relation to Metabolic and Inflammatory Markers: A Community-Based Study

BACKGROUND

Population studies investigating the contribution of immunometabolic disturbances to heart dysfunction remain scarce. We combined high-throughput biomarker profiling, multidimensional network analyses, and regression statistics to identify immunometabolic markers associated with subclinical heart dysfunction in the community.

METHODS

In 1,236 individuals (mean age, 51.0 years; 51.5% women), we measured 39 immunometabolic markers and assessed echocardiographic indexes of left ventricular diastolic dysfunction (LVDD) and left atrial (LA) reservoir dysfunction. We used partial least squares (PLS) to filter the most relevant biomarkers related to the echocardiographic characteristics. Subsequently, we assessed the associations between the echocardiographic features and biomarkers selected in PLS while accounting for clinical confounders.

RESULTS

Influential biomarkers in PLS of echocardiographic characteristics included blood sugar, γ-glutamyl transferase, d-dimer, ferritin, hemoglobin, interleukin (IL)-4, IL-6, and serum insulin and uric acid. In stepwise regression incorporating clinical confounders, higher d-dimer was independently associated with higher E/e' ratio and LA volume index (P ≤ 0.05 for all). In multivariable-adjusted analyses, the risk for LVDD increased with higher blood sugar and d-dimer (P ≤ 0.048). After full adjustment, higher serum insulin and serum uric acid were independently related to worse LA reservoir strain and higher risk for LA reservoir dysfunction (P ≤ 0.039 for all). The biomarker panels detected LVDD and LA reservoir dysfunction with 87% and 79% accuracy, respectively (P < 0.0001).

CONCLUSIONS

Biomarkers of insulin resistance, hyperuricemia, and chronic low-grade inflammation were associated with cardiac dysfunction. These biomarkers might help to unravel cardiac pathology and improve the detection and management of cardiac dysfunction in clinical practice.

Association between Iron Status and Incident Type 2 Diabetes: A Population-Based Cohort Study

Type 2 diabetes poses a major public health challenge. Here, we conducted a cohort study with a large sample size to determine the association of baseline serum ferritin (SF), a marker of iron status, with incident type 2 diabetes in primary healthcare patients in Catalonia, a western Mediterranean region. A total of 206,115 patients aged 35–75 years without diabetes and with available baseline SF measurements were eligible. The variables analyzed included sociodemographic characteristics, anthropometry, lifestyle, morbidity and iron status (SF, serum iron and hemoglobin). Incident type 2 diabetes during follow-up (2006–2016) was ascertained using the International Classification of Diseases, 10th edition. Cox proportional-hazards models adjusted for multiple baseline confounders/mediators were used to estimate hazard ratios (HRs). Over a median follow-up of 8.4 years, 12,371 new cases of type 2 diabetes were diagnosed, representing an incidence rate of 7.5 cases/1000 persons/year. Since at baseline, the median SF concentration was higher in subjects who developed type 2 diabetes (107.0 µg/L vs. 60.3 µg/L; p < 0.001), SF was considered an independent risk predictor for type 2 diabetes; the multivariable-adjusted HRs for incident type 2 diabetes across SF quartiles 1–4 were 1.00 (reference), 0.95 (95% CI = 0.85–1.06), 1.18 (95% CI = 1.65–1.31) and 1.51 (95% CI = 1.36–1.65), respectively. Our study suggested that higher baseline SF was significantly associated with an increased risk of new-onset type 2 diabetes in Catalan primary healthcare users, supporting the relevance of monitoring iron stores in order to improve the diagnosis and management of diabetes in clinical practice.

Prevalence and determinants of the precursor stages of heart failure: results from the population-based STAAB cohort study

Aims

Prevention of heart failure relies on the early identification and control of risk factors. We aimed to identify the frequency and characteristics of individuals at risk of heart failure in the general population.

Methods and Results

We report cross-sectional data from the prospective Characteristics and Course of Heart Failure Stages A–B and Determinants of Progression (STAAB) cohort study investigating a representative sample of residents of Würzburg, Germany. Sampling was stratified 1:1 for sex and 10:27:27:27:10 for age groups of 30–39/40–49/50–59/60–69/70–79 years. Heart failure precursor stages were defined according to American College of Cardiology/American Heart Association: stage A (risk factors for heart failure), stage B (asymptomatic cardiac dysfunction). The main results were internally validated in the second half of the participants. The derivation sample comprised 2473 participants (51% women) with a distribution of 10%/28%/25%/27%/10% in respective age groups. Stages A and B were prevalent in 42% and 17% of subjects, respectively. Of stage B subjects, 31% had no risk factor qualifying for stage A (group ‘B-not-A’). Compared to individuals in stage B with A criteria, B-not-A were younger, more often women, and had left ventricular dilation as the predominant B qualifying criterion (all P &lt; 0.001). These results were confirmed in the validation sample (n = 2492).

Conclusion

We identified a hitherto undescribed group of asymptomatic individuals with cardiac dysfunction predisposing to heart failure, who lacked established heart failure risk factors and therefore would have been missed by conventional primary prevention. Further studies need to replicate this finding in independent cohorts and characterise their genetic and -omic profile and the inception of clinically overt heart failure in subjects of group B-not-A.

Loss of Cardiac Ferritin H Facilitates Cardiomyopathy via Slc7a11-Mediated Ferroptosis

RATIONALE

Maintaining iron homeostasis is essential for proper cardiac function. Both iron deficiency and iron overload are associated with cardiomyopathy and heart failure via complex mechanisms. Although ferritin plays a central role in iron metabolism by storing excess cellular iron, the molecular function of ferritin in cardiomyocytes remains unknown.

OBJECTIVE

To characterize the functional role of Fth (ferritin H) in mediating cardiac iron homeostasis and heart disease.

METHODS AND RESULTS

Mice expressing a conditional Fth knockout allele were crossed with 2 distinct Cre recombinase-expressing mouse lines, resulting in offspring that lack Fth expression specifically in myocytes (MCK-Cre) or cardiomyocytes (Myh6-Cre). Mice lacking Fth in cardiomyocytes had decreased cardiac iron levels and increased oxidative stress, resulting in mild cardiac injury upon aging. However, feeding these mice a high-iron diet caused severe cardiac injury and hypertrophic cardiomyopathy, with molecular features typical of ferroptosis, including reduced glutathione (GSH) levels and increased lipid peroxidation. Ferrostatin-1, a specific inhibitor of ferroptosis, rescued this phenotype, supporting the notion that ferroptosis plays a pathophysiological role in the heart. Finally, we found that Fth-deficient cardiomyocytes have reduced expression of the ferroptosis regulator Slc7a11, and overexpressing Slc7a11 selectively in cardiomyocytes increased GSH levels and prevented cardiac ferroptosis.

CONCLUSIONS

Our findings provide compelling evidence that ferritin plays a major role in protecting against cardiac ferroptosis and subsequent heart failure, thereby providing a possible new therapeutic target for patients at risk of developing cardiomyopathy.

Association Between Norepinephrine Levels and Abnormal Iron Status in Patients With Chronic Heart Failure: Is Iron Deficiency More Than a Comorbidity?

Background

Mechanisms underlying iron homeostasis dysregulation in patients with chronic heart failure remain unsettled. In cardiomyocyte models, norepinephrine may lead to intracellular iron depletion, but the potential association between catecholamines (sympathetic activation markers) and iron metabolism biomarkers in chronic heart failure is unknown.

Methods and Results

In this cross‐sectional analysis, we studied the association between plasma norepinephrine levels and serum iron status biomarkers indicating iron storage (ferritin), iron transport (transferrin saturation), and iron demand (soluble transferrin receptor) in a prospective cohort of 742 chronic heart failure patients (mean age, 72±11 years; 56% male). Impaired iron status was defined as ferritin <100 μg/L or transferrin saturation <20%. Impaired iron status was observed in 69% of patients. In multivariate models, greater norepinephrine levels were associated with impaired iron transport (transferrin saturation <20%, odds ratio=2.28; 95% CI [1.19–4.35]; P=0.013), but not with impaired iron storage (ferritin <100 μg/L, odds ratio=1.25; 95% CI [0.73–2.16]; P=0.415). Norepinephrine was a significant predictor of increased iron demand (soluble transferrin receptor, standardized β‐coefficient=0.12; P=0.006) and low transferrin saturation (standardized β‐coefficient=−0.12; P=0.003). However, norepinephrine levels were not associated with iron or ferritin levels (P>0.05). Adjusted norepinephrine marginal means were significantly higher in patients with impaired iron status compared with those with normal iron status (528 pg/mL [505–551] versus 482 pg/mL [448–518], respectively; P=0.038).

Conclusions

In chronic heart failure patients, increased sympathetic activation estimated with norepinephrine levels is associated with impaired iron status and, particularly, dysregulation of biomarkers suggesting impaired iron transport and increased iron demand. Whether the relationship between norepinephrine and iron metabolism is bidirectional and entails causality need to be elucidated in future research.

H-Ferritin is essential for macrophages' capacity to store or detoxify exogenously added iron

Macrophages are central cells both in the immune response and in iron homeostasis. Iron is both essential and potentially toxic. Therefore, iron acquisition, transport, storage, and release are tightly regulated, by several important proteins. Cytosolic ferritin is an iron storage protein composed of 24 subunits of either the L- or the H-type chains. H-ferritin differs from L-ferritin in the capacity to oxidize Fe²⁺ to Fe³⁺. In this work, we investigated the role played by H-ferritin in the macrophages’ ability to respond to immune stimuli and to deal with exogenously added iron. We used mice with a conditional deletion of the H-ferritin gene in the myeloid lineage to obtain bone marrow-derived macrophages. These macrophages had normal viability and gene expression under basal culture conditions. However, when treated with interferon-gamma and lipopolysaccharide they had a lower activation of Nitric Oxide Synthase 2. Furthermore, H-ferritin-deficient macrophages had a higher sensitivity to iron-induced toxicity. This sensitivity was associated with a lower intracellular iron accumulation but a higher production of reactive oxygen species. These data indicate that H-ferritin modulates macrophage response to immune stimuli and that it plays an essential role in protection against iron-induced oxidative stress and cell death.

Ferritin in Kidney and Vascular Related Diseases: Novel Roles for an Old Player

Iron is at the forefront of a number of pivotal biological processes due to its ability to readily accept and donate electrons. However, this property may also catalyze the generation of free radicals with ensuing cellular and tissue toxicity. Accordingly, throughout evolution numerous pathways and proteins have evolved to minimize the potential hazardous effects of iron cations and yet allow for readily available iron cations in a wide variety of fundamental metabolic processes. One of the extensively studied proteins in the context of systemic and cellular iron metabolisms is ferritin. While clinicians utilize serum ferritin to monitor body iron stores and inflammation, it is important to note that the vast majority of ferritin is located intracellularly. Intracellular ferritin is made of two different subunits (heavy and light chain) and plays an imperative role as a safe iron depot. In the past couple of decades our understanding of ferritin biology has remarkably improved. Additionally, a significant body of evidence has emerged describing the significance of the kidney in iron trafficking and homeostasis. Here, we briefly discuss some of the most important findings that relate to the role of iron and ferritin heavy chain in the context of kidney-related diseases and, in particular, vascular calcification, which is a frequent complication of chronic kidney disease.

HFE H63D Polymorphism and the Risk for Systemic Hypertension, Myocardial Remodeling, and Adverse Cardiovascular Events in the ARIC Study

H63D has been identified as a novel locus associated with the development of hypertension. The quantitative risks for hypertension, cardiac remodeling, and adverse events are not well studied. We analyzed white participants from the ARIC study (Atherosclerosis Risk in Communities) with H63D genotyping (N=10 902). We related genotype status to prevalence of hypertension at each of 5 study visits and risk for adverse cardiovascular events. Among visit 5 participants (N=4507), we related genotype status to echocardiographic features. Frequencies of wild type (WT)/WT, H63D/WT, and H63D/H63D were 73%, 24.6%, and 2.4%. The average age at baseline was 54.9±5.7 years and 47% were men. Participants carrying the H63D variant had higher systolic blood pressure ( P=0.004), diastolic blood pressure (0.012), and more frequently had hypertension ( P<0.001). Compared with WT/WT, H63D/WT and H63D/H63D participants had a 2% to 4% and 4% to 7% absolute increase in hypertension risk at each visit, respectively. The population attributable risk of H63D for hypertension among individuals aged 45 to 64 was 3.2% (95% CI, 1.3-5.1%) and 1.3% (95% CI, 0.0-2.4%) among individuals >65 years. After 25 years of follow-up, there was no relationship between genotype status and any outcome ( P>0.05). H63D/WT and H63D/H63D genotypes were associated with small differences in cardiac remodeling. In conclusion, the HFE H63D variant confers an increased risk for hypertension per allele and, given its frequency, accounts for a significant number of cases of hypertension. However, there was no increased risk for adverse cardiovascular events or substantial left ventricular remodeling.

Increased Ferritin Concentration and Risk of Atrial Fibrillation and Heart Failure in Men and Women: Three Studies of the Danish General Population Including 35799 Individuals

BACKGROUND

Moderately increased plasma ferritin, as a biomarker of iron overload, has been associated with higher rates of cardiovascular death and heart failure. However, the association of moderately increased plasma ferritin with risk of atrial fibrillation in the general population is unknown.

METHODS

We examined the association of plasma ferritin concentrations with risk of atrial fibrillation and heart failure in metaanalyses of 35799 men and women from 3 studies of the Danish general population: the Copenhagen City Heart Study, the Danish General Suburban Population Study, and the Copenhagen General Population Study.

RESULTS

Multivariable adjusted fixed effects odds ratios for atrial fibrillation were 1.23 (95% CI, 1.05-1.44; P = 0.005) in men for ferritin concentration ≥300 μg/L vs <300 μg/L, 1.13 (95% CI, 0.93-1.38; P = 0.22) in women for ≥200 μg/L vs <200 μg/L, and 1.19 (95% CI, 1.06-1.35; P = 0.005) in both sexes combined (P _{sex interaction} = 0.52). Corresponding fixed effects odds ratios for heart failure were 1.16 (95% CI, 0.98-1.37; P = 0.08) in men, 0.86 (95% CI, 0.67-1.10; P = 0.23) in women, and 1.05 (95% CI, 0.91-1.21; P = 0.45) in both sexes combined (P _{sex interaction} = 0.05). Multivariable adjusted fixed effects odds ratio for atrial fibrillation per step increase in ferritin concentrations was 1.13 (95% CI, 1.06-1.21; P _trend = 0.0005) in both sexes combined (P _{sex interaction} = 0.59); the corresponding value for heart failure was 1.03 (95% CI, 0.95-1.11; P _trend = 0.47) (P _{sex interaction} = 0.08). In sensitivity analyses, there was no evidence of U-shaped relationships between plasma ferritin concentrations and risk of atrial fibrillation or heart failure in men or women.

CONCLUSIONS

Increased ferritin concentration is associated with increased risk of atrial fibrillation in the general population.

Iron loading, alcohol and mortality: A prospective study

BACKGROUND & AIMS

The relationship between total body iron and cardiovascular disease remains controversial and information absent in black sub-Saharan Africans in whom alcohol consumption tends to be high. The level of total body iron is tightly regulated, however this regulation is compromised by high alcohol intake causing iron loading. The aim of this study is to investigate total body iron, as represented by serum ferritin, and its interaction with measures of alcohol intake in predicting all-cause and cardiovascular mortality.

METHODS

We followed health outcomes for a median of 9.22 years in 877 randomly selected HIV negative African women (mean age: 50.4 years).

RESULTS

One hundred and five deaths occurred of which 40 were cardiovascular related. Ferritin averaged 84.0 (5th to 95th percentile interval, 7.5-533.3) ng/ml and due to the augmenting effect of inflammation, lowered to 75.3 (6.9-523.2) ng/ml after excluding 271 participants with high-sensitivity C-reactive protein (CRP) levels (above 8 mg/l). CRP increased by quartiles of ferritin in the total group (P trend = 0.002), but this relationship was absent after excluding the 271 participants with high CRP values (P trend = 0.10). Ferritin, gamma-glutamyl transferase and carbohydrate deficient transferrin (all P < 0.0001) were higher in drinkers compared to non-drinkers, but CRP was similar (P = 0.77). In multivariable-adjusted analyses, ferritin predicted both all-cause (hazard ratio, 2.08; 95% confidence interval, 1.62-2.68; P < 0.0001) and cardiovascular (1.94; 1.29-2.92; P = 0.002) mortality. In participants with CRP levels below or equal to 8 mg/l, the significant relationship remained between ferritin and all-cause (2.51; 1.81-3.49; P < 0.0001) and cardiovascular mortality (2.34; 1.45-3.76; P = 0.0005). In fully adjusted models, interactions existed between ferritin and gamma-glutamyl transferase, self-reported alcohol use and carbohydrate deficient transferrin in predicting all-cause (P ≤ 0.012) and cardiovascular mortality (P ≤ 0.003).

CONCLUSIONS

Iron loading in African women predicted all-cause and cardiovascular mortality and the intake of alcohol seems mechanistically implicated.

Excessive Erythrocytosis and Cardiovascular Risk in Andean Highlanders

Corante, Noemí, Cecilia Anza-Ramírez, Rómulo Figueroa-Mujíca, José Luis Macarlupú, Gustavo Vizcardo-Galindo, Grzegorz Bilo, Gianfranco Parati, Jorge L. Gamboa, Fabiola León-Velarde, and Francisco C. Villafuerte. Excessive erythrocytosis and cardiovascular risk in Andean highlanders. High Alt Med Biol. 19:221–231, 2018.—Cardiovascular diseases are the main cause of death worldwide. Life under high-altitude (HA) hypoxic conditions is believed to provide highlanders with a natural protection against cardiovascular and metabolic diseases compared with sea-level inhabitants. However, some HA dwellers become intolerant to chronic hypoxia and develop a progressive incapacitating syndrome known as chronic mountain sickness (CMS), characterized by excessive erythrocytosis (EE; Hb ≥21 g/dL in men, Hb ≥19 g/dL in women). Evidence from HA studies suggests that, in addition to CMS typical signs and symptoms, these highlanders may also suffer from metabolic and cardiovascular disorders. Thus, we hypothesize that this syndrome is also associated to the loss of the cardiometabolic protection observed in healthy highlanders (HH), and therefore to a higher cardiovascular risk (CVR). The aim of the present work was to evaluate the association between EE and CVR calculated using the Framingham General CVR Score and between EE and CVR factors in male highlanders. This cross-sectional study included 342 males from Cerro de Pasco, Peru at 4340 m (HH = 209, CMS = 133). Associations were assessed by multiple logistic regressions adjusted for potential confounders (BMI, pulse oxygen saturation and age). The adjusted models show that the odds of high CVR (>20%) in highlanders with EE was 3.63 times the odds in HH (CI 95%:1.22–10.78; p = 0.020), and that EE is associated to hypertension, elevated fasting serum glucose, insulin resistance, and elevated fasting serum triglycerides. Our results suggest that individuals who suffer from EE are at increased risk of developing cardiovascular events compared with their healthy counterparts.

Positive Iron Balance in Chronic Kidney Disease: How Much is Too Much and How to Tell?

BACKGROUND

Regulation of body iron occurs at cellular, tissue, and systemic levels. In healthy individuals, iron absorption and losses are minimal, creating a virtually closed system. In the setting of chronic kidney disease and hemodialysis (HD), increased iron losses, reduced iron absorption, and limited iron availability lead to iron deficiency. Intravenous (IV) iron therapy is frequently prescribed to replace lost iron, but determining an individual's iron balance and stores can be challenging and imprecise, contributing to uncertainty about the long-term safety of IV iron therapy.

SUMMARY

Patients on HD receiving judicious doses of IV iron are likely to be in a state of positive iron balance, yet this does not appear to confer an overt risk for clinically relevant iron toxicity. The concomitant use of iron with erythropoiesis-stimulating agents, the use of maintenance iron dosing regimens, and the reticuloendothelial distribution of hepatic iron deposition likely minimize the potential for iron toxicity in patients on HD. Key Messages: Because no single diagnostic test can, at present, accurately assess iron status and risk for toxicity, clinicians need to take an integrative approach to avoid iron doses that impose excessive exposure while ensuring sufficient replenishment of iron stores capable of overcoming hepcidin blockade and allowing for effective erythropoiesis.

Therapeutic Targeting of PDEs and PI3K in Heart Failure with Preserved Ejection Fraction (HFpEF)

PURPOSE OF REVIEW

Heart Failure with preserved Ejection Fraction (HFpEF) is a prevalent disease with considerable individual and societal burden. HFpEF patients often suffer from multiple pathological conditions thatcomplicate management and adversely affect outcome, including pulmonary hypertension and chronic obstructive pulmonary disease (COPD). To date, no treatment proved to be fully effective in reducing morbidity and mortality in HFpEF, possibly due to an incomplete understanding of the underlying molecular mechanisms.

RECENT FINDINGS

The emerging view proposes chronic systemic inflammation, leading to endothelial dysfunction and interstitial fibrosis, as a prominent cause of HFpEF, rather than a mere co-existent disease. In the last decade, efforts from pharmaceutical companies attempted to target pharmacologically enzymes which play key roles in systemic and lung inflammation, such as the cyclic nucleotide-degrading enzymes phosphodiesterases (PDEs) and phosphoinositide-3 phosphate kinases (PI3Ks), especially to limit COPD. In this review, we will summarize major successes and drawbacks of hitting these enzymes to tackle inflammation in HFpEF-associated co-morbidities, with a major focus on the results of completed and ongoing clinical trials. Finally, we will discuss the potential of repurposing and/or developing new PDE and PI3K inhibitors for HFpEF therapy.

Hyperferritinemia and inflammation

Understanding of ferritin biology has traditionally centered on its role in iron storage and homeostasis, with low ferritin levels indicative of deficiency and high levels indicative of primary or secondary hemochromatosis. However, further work has shown that iron, redox biology and inflammation are inexorably linked. During infection, increased ferritin levels represent an important host defense mechanism that deprives bacterial growth of iron and protects immune cell function. It may also be protective, limiting the production of free radicals and mediating immunomodulation. Additionally, hyperferritinemia is a key acute-phase reactants, used by clinicians as an indication for therapeutic intervention, aimed at controlling inflammation in high-risk patients. One school of thought maintains that hyperferritinemia is an 'innocent bystander' biomarker of uncontrolled inflammation that can be used to gauge effectiveness of intervention. Other schools of thought maintain that ferritin induction could be a protective negative regulatory loop. Others maintain that ferritin is a key mediator of immune dysregulation, especially in extreme hyperferritinemia, via direct immune-suppressive and pro-inflammatory effects. There is a clear need for further investigation of the role of ferritin in uncontrolled inflammatory conditions both as a biomarker and mediator of disease because its occurrence identifies patients with high mortality risk and its resolution predicts their improved survival.