Dietary iron deficiency induces ventricular dilation, mitochondrial ultrastructural aberrations and cytochrome c release: involvement of nitric oxide synthase and protein tyrosine nitration

Identification of three mechanistic pathways for iron-deficient heart failure

Current understanding of iron-deficient heart failure is based on blood tests that are thought to reflect systemic iron stores, but the available evidence suggests greater complexity. The entry and egress of circulating iron is controlled by erythroblasts, which (in severe iron deficiency) will sacrifice erythropoiesis to supply iron to other organs, e.g. the heart. Marked hypoferraemia (typically with anaemia) can drive the depletion of cardiomyocyte iron, impairing contractile performance and explaining why a transferrin saturation < ≈15%-16% predicts the ability of intravenous iron to reduce the risk of major heart failure events in long-term trials (Type 1 iron-deficient heart failure). However, heart failure may be accompanied by intracellular iron depletion within skeletal muscle and cardiomyocytes, which is disproportionate to the findings of systemic iron biomarkers. Inflammation- and deconditioning-mediated skeletal muscle dysfunction-a primary cause of dyspnoea and exercise intolerance in patients with heart failure-is accompanied by intracellular skeletal myocyte iron depletion, which can be exacerbated by even mild hypoferraemia, explaining why symptoms and functional capacity improve following intravenous iron, regardless of baseline haemoglobin or changes in haemoglobin (Type 2 iron-deficient heart failure). Additionally, patients with advanced heart failure show myocardial iron depletion due to both diminished entry into and enhanced egress of iron from the myocardium; the changes in iron proteins in the cardiomyocytes of these patients are opposite to those expected from systemic iron deficiency. Nevertheless, iron supplementation can prevent ventricular remodelling and cardiomyopathy produced by experimental injury in the absence of systemic iron deficiency (Type 3 iron-deficient heart failure). These observations, taken collectively, support the possibility of three different mechanistic pathways for the development of iron-deficient heart failure: one that is driven through systemic iron depletion and impaired erythropoiesis and two that are characterized by disproportionate depletion of intracellular iron in skeletal and cardiac muscle. These mechanisms are not mutually exclusive, and all pathways may be operative at the same time or may occur sequentially in the same patients.

Intravenous iron therapy for heart failure and iron deficiency: An updated meta-analysis of randomized clinical trials

Heart failure (HF) patients frequently exhibit iron deficiency, which is associated with a poor prognosis. Although various trials have been conducted, it is uncertain if intravenous (IV) iron replenishment improves clinical outcomes in HF patients with iron deficiency. A comprehensive literature search was conducted using PubMed/MEDLINE, Embase, and the Cochrane Library from inception till 15 September 2023 to retrieve randomized controlled trials (RCTs) that compared IV iron therapy with placebo or standard of care in patients with HF and iron deficiency. Clinical outcomes were assessed by generating forest plots using the random-effects model and pooling odds ratios (ORs) or weighted mean differences (WMDs). Fourteen RCTs with 6651 patients were included. IV iron therapy showed a significantly reduced incidence of the composite of first heart failure hospitalization (HHF) or cardiovascular (CV) mortality as compared with the control group (OR = 0.73, 95% CI: 0.58 to 0.92). The IV iron therapy resulted in a trend towards lower CV mortality (OR = 0.88, 95% CI: 0.76 to 1.01), 1-year all-cause mortality (OR = 0.85, 95% CI: 0.71 to 1.02), and first HHF (OR = 0.73, 95% CI: 0.51 to 1.05), and an improved left ventricular ejection fraction (LVEF) (MD = 4.54, 95% CI: -0.13 to 9.21). Meta-regression showed a significant inverse moderating effect of baseline LVEF on the first HHF or CV death. In patients with HF and iron deficiency, IV iron therapy reduced the incidence of composite of first HHF or CV mortality. There was a trend of lower overall CV and 1-year all-cause mortality, first HHF, and improved LVEF with IV iron therapy.

Iron Deficiency and Incident Heart Failure in Older Community-Dwelling Individuals

AIMS

Among persons with prevalent heart failure (HF), iron deficiency has been linked to HF admissions, and intravenous iron replacement improves HF outcomes. Recent studies in persons with chronic kidney disease (CKD) demonstrate that iron deficiency is associated with incident HF. This study aimed to determine the relationship of iron status with incident HF in community-dwelling older adults irrespective of their kidney function.

METHODS

In this case-cohort study, 1,006 Cardiovascular Health Study participants (785 from the random sub-cohort [including 193 HF cases] and 221 additional HF cases [N = 414 total HF cases]) aged ≥ 65 years without HF (41% with CKD), we used weighted Cox models to evaluate associations of iron status with incident HF. Participants were categorized based on quartiles of transferrin saturation and ferritin as "iron replete" (27.3%), "functional iron deficiency" (7.7%), "iron deficiency" (11.8%), "mixed iron deficiency" (5.6%), "high iron" (9.3%) and "non-classified" (38.1%), consistent with prior studies.

RESULTS

Compared to older persons who were iron replete, those with iron deficiency were at higher risk of incident HF (HR 1.47; 1.02-2.11) in models adjusting for demographics, HF risk factors, and estimated glomerular filtration rate. Other iron categories did not associate with incident HF. The relationship of iron deficiency with incident HF did not differ by CKD status (interaction P value 0.2).

CONCLUSIONS

Among community-dwelling elders, iron deficiency is independently associated with incident HF, an association that was similar irrespective of CKD status. Our findings support conduct of clinical trials of iron replacement for prevention of HF in older adults with iron deficiency.

The Impact of Iron Deficiency on Disease Severity and Myocardial Function in Cardiac Amyloidosis

Background

Reduced cardiac energy is a hallmark feature of heart failure and is common in cardiac amyloidosis (CA) and can be aggravated by the presence of iron deficiency.

Methods

Retrospective analysis of a single tertiary care center CA registry. Prevalence of iron deficiency was determined based on two definitions: (1) Classic definition, ferritin < 100 µg/L irrespective of transferin saturation (TSAT) or ferritin between 100 and 300 µg/L with a TSAT < 20%, and (2) TSAT-based definition, TSAT < 20%.

Results

Out of a total of 393 CA patients who had a full set of iron indices (44% light chain [AL]-CA, 50% transthyretin [ATTR]-CA, remainder other or unspecified CA subtype), 56% had iron deficiency according to the classic definition and 58% according to the TSAT definition, with similar prevalence in AL-CA vs ATTR-CA (p = .135). Per both definitions 58% had anemia. Only the TSAT-based definition was associated with worse functional status (p = .039) and worse cardiac function. CA patients with a TSAT < 20% illustrated features of more pronounced right ventricular (RV) failure including lower TAPSE on echocardiography, lower RV ejection fraction and RV stroke volume index on CMR, increased right-sided filling pressures, lower pulmonary artery pulsatility index, and higher RAP/PCWP ratio by right heart catheterization. Neither the classic nor the TSAT-based definition was associated with a higher risk of all-cause mortality after covariate adjustment.

Conclusion

Iron deficiency is common in cardiac amyloidosis and, when identified with a TSAT < 20%, is associated with worse functional status and more pronounced RV disease, but not with a higher risk of all-cause mortality.

Critical re-evaluation of the identification of iron deficiency states and effective iron repletion strategies in patients with chronic heart failure

According to current guidelines, iron deficiency is defined by a serum ferritin level <100 ng/ml or a transferrin saturation (TSAT) <20% if the serum ferritin level is 100-299 μg/L. These criteria were developed to encourage the use of intravenous iron as an adjunct to erythropoiesis-stimulating agents in the treatment of renal anaemia. However, in patients with heart failure, these criteria are not supported by any pathophysiological or clinical evidence that they identify an absolute or functional iron deficiency state. A low baseline TSAT-but not serum ferritin level-appears to be a reliable indicator of the effect of intravenous iron to reduce major heart failure events. In randomized controlled trials, intravenous iron decreased the risk of cardiovascular death or total heart failure hospitalization in patients with a TSAT <20% (risk ratio 0.67 [0.49-0.92]) but not in patients with a TSAT ≥20% (risk ratio 0.99 [0.74-1.30]), with the magnitude of the risk reduction being proportional to the severity of hypoferraemia. Patients who were enrolled in clinical trials solely because they had a serum ferritin level <100 μg/L showed no significant benefit on heart failure outcomes, and it is noteworthy that serum ferritin levels of 20-300 μg/L lie entirely within the range of normal values for healthy adults. Current guidelines reflect the eligibility criteria of clinical trials, which inadvertently adopted unvalidated criteria to define iron deficiency. Reliance on these guidelines would lead to the treatment of many patients who are not iron deficient (serum ferritin level <100 μg/L but normal TSAT) and ignores the possibility of iron deficiency in patients with a low TSAT but with serum ferritin level of >300 μg/L. Importantly, analyses of benefit based on trial eligibility-driven guidelines substantially underestimate the magnitude of heart-failure-event risk reduction with intravenous iron in patients who are truly iron deficient. Based on all available data, we recommend a new mechanism-based and trial-tested approach that reflects the totality of evidence more faithfully than the historical process adopted by clinical investigators and by the guidelines. Until additional evidence is forthcoming, an iron deficiency state in patients with heart failure should be defined by a TSAT <20% (as long as the serum ferritin level is <400 μg/L), and furthermore, the use of a serum ferritin level <100 μg/L alone as a diagnostic criterion should be discarded.

Influx of zwitterionic buffer after intracytoplasmic sperm injection (ICSI) membrane piercing alters the transcriptome of human oocytes

PURPOSE/STUDY QUESTION

Does piercing oocyte membranes during ICSI allow the influx of surrounding zwitterionic buffer into human oocytes and result in altered developmental competence?

METHODS

Human oocytes directed to IRB-approved research were used to determine the unrestricted influx of surrounding buffer into the oocyte after piercing of membranes via confocal fluorescence microscopy (n = 80 human MII oocytes) and the influence of the select buffer influx of HEPES, MOPS, and bicarbonate buffer on the oocyte transcriptome using ultra-low input RNA sequencing (n = 40 human MII oocytes).

RESULTS

Piercing membranes of human MII oocytes during sham-ICSI resulted in the unrestricted influx of surrounding culture buffer into the oocyte that was beyond technician control. Transcriptome analysis revealed statistically significant decreased cytoskeletal transcripts in the pierced buffer cohorts, higher levels of embryo competency transcripts (IGF2 and G6PD) in the bicarbonate buffer cohort, higher levels of stress-induced transcriptional repressor transcripts (MAF1) in the HEPES and MOPS cohorts, and decreased levels of numerous chromosomal maintenance transcripts (SMC3) in the HEPES buffer cohort. The HEPES buffer cohort also revealed higher levels of transcripts suggesting increased oxidative (GPX1) and lysosomal stress (LAMP1).

CONCLUSION

The influence of zwitterionic buffer on intrinsic cellular mechanisms provides numerous concerns for their use in IVF clinical applications. The primary concern is the ICSI procedure, in which the surrounding buffer is allowed influx into the oocytes after membrane piercing. Selecting a physiological bicarbonate buffer may reduce imposed stress on oocytes, resulting in improved embryo development and clinical results because intracellular MOPS, and especially HEPES, may negatively impact intrinsic biological mechanisms, as revealed by transcriptome changes. These findings further support the utilization of bicarbonate buffer as the oocyte-holding medium during ICSI.

Benefits of intravenous iron supplementation in heart failure

Introduction: Iron deficiency (ID) is one of the most frequent comorbidities in patients with heart failure (HF) and is estimated to be present in up to 80% of acute patients regardless of their ejection fraction. Randomized controlled trials have shown that supplementary intravenous iron results in improved clinical outcomes; however, the current understanding of the effects of intravenous iron on morbidity and mortality remains limited. Study and results: The meta-analysis pooled individual participant data from three randomized placebo-controlled trials of ferric carboxymaltose (FCM) in adult patients (n = 4,501) with heart failure and iron deficiency (CONFIRM-HF, AFFIRM-AHF, and HEART-FID). FCM therapy significantly reduced the co-primary composite endpoint of total cardiovascular hospitalizations and cardiovascular death, with a rate ratio (RR 0.86; 95% CI 0.75 to 0.98; p = 0.029). FCM therapy was associated with a 17% relative rate reduction in total cardiovascular hospitalizations (RR 0.83; 95% CI 0.73 to 0.96; p = 0.009) and a 16% relative rate reduction in total heart failure hospitalizations (RR 0.84; 95% CI 0.71 to 0.98; p = 0.025). Lessons learned: The meta-analysis shows that in iron-deficient patients with heart failure and reduced or mildly reduced left ventricular ejection fraction, intravenous ferric carboxymaltose (FCM) is associated with a reduced risk of total cardiovascular hospitalization and cardiovascular mortality. These findings indicate that intravenous FCM should be considered in iron-deficient patients with heart failure and reduced or mildly reduced ejection fractions.

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.

Long-term dietary iron intake and risk of non-fatal cardiovascular diseases in the China Health and Nutrition Survey

AIMS

We aimed to investigate the association of long-term dietary iron intake with the risk of non-fatal cardiovascular diseases (CVDs), myocardial infarction (MI), and stroke in Chinese populations with predominantly plant-based diets by sex.

METHODS AND RESULTS

A total of 17 107 participants (8569 men and 8538 women) aged 18-80 years in the China Health and Nutrition Survey (CHNS) 1989-2015 were included. Dietary intake was assessed repeatedly by three consecutive 24-h dietary recalls. Cox proportional hazard models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs). During a median follow-up of 11.1 years, the adjusted HRs (95% CIs) for non-fatal CVDs risk across quintiles of total iron intake in men were 1.00, 0.65 (0.46-0.93), 0.54 (0.37-0.78), 0.66 (0.46-0.94), 0.69 (0.47-1.03), but no significant association in women. Similar associations were found for stroke risk, but not for MI risk. The dose-response curves for the association of total iron and non-heme iron intake with the risk of non-fatal CVDs and stroke followed a reverse J-shape only in men and similar reverse J-shaped association of heme iron intake with non-fatal CVDs and stroke risk in both men and women (P-non-linearity <0.05).

CONCLUSION

Moderate dietary iron intake may protect against non-fatal CVDs and stroke, especially in Chinese men consuming plant-based diets. Both quantity and quality of dietary iron intake should be considered in the prevention of non-fatal CVDs due to differences in dietary patterns among diverse populations.

Modulation of the nitric oxide/cGMP pathway in cardiac contraction and relaxation: Potential role in heart failure treatment

Evidence exists that heart failure (HF) has an overall impact of 1-2 % in the global population being often associated with comorbidities that contribute to increased disease prevalence, hospitalization, and mortality. Recent advances in pharmacological approaches have significantly improved clinical outcomes for patients with vascular injury and HF. Nevertheless, there remains an unmet need to clarify the crucial role of nitric oxide/cyclic guanosine 3',5'-monophosphate (NO/cGMP) signalling in cardiac contraction and relaxation, to better identify the key mechanisms involved in the pathophysiology of myocardial dysfunction both with reduced (HFrEF) as well as preserved ejection fraction (HFpEF). Indeed, NO signalling plays a crucial role in cardiovascular homeostasis and its dysregulation induces a significant increase in oxidative and nitrosative stress, producing anatomical and physiological cardiac alterations that can lead to heart failure. The present review aims to examine the molecular mechanisms involved in the bioavailability of NO and its modulation of downstream pathways. In particular, we focus on the main therapeutic targets and emphasize the recent evidence of preclinical and clinical studies, describing the different emerging therapeutic strategies developed to counteract NO impaired signalling and cardiovascular disease (CVD) development.

Iron Deficiency in Heart Failure: A Scientific Statement from the Heart Failure Society of America

Iron deficiency is present in approximately 50% of patients with symptomatic heart failure and is independently associated with worse functional capacity, lower quality of, life and increased mortality. The purpose of this document is to summarize current knowledge of how iron deficiency is defined in heart failure and its epidemiology and pathophysiology, as well as pharmacological considerations for repletion strategies. This document also summarizes the rapidly expanding array of clinical trial evidence informing when, how, and in whom to consider iron repletion.

Effect of intravenous iron replacement on recurrent heart failure hospitalizations and cardiovascular mortality in patients with heart failure and iron deficiency: A Bayesian meta-analysis

AIMS

Iron deficiency is common in patients with heart failure (HF) and reduced ejection fraction (HFrEF) and is associated with a poor prognosis. Whether intravenous iron replacement improves recurrent HF hospitalizations and cardiovascular mortality of these patients is uncertain although several trials were conducted. Moreover, none of the trials were powered to assess the effect of intravenous iron in clinically important subgroups. Therefore, we conducted a Bayesian analysis to derive precise estimates of the effect of intravenous iron replacement on recurrent HF hospitalizations and cardiovascular mortality in iron-deficient HFrEF patients using consistent subgroup definitions across trials.

METHODS AND RESULTS

Individual participant data were used from the FAIR-HF (n = 459), CONFIRM-HF (n = 304) and AFFIRM-AHF (n = 1108) trials. These data were re-analysed following as closely as possible the approach taken in the analyses of IRONMAN (n = 1137), for which study level data were used. Definitions of outcomes and subgroups from the FAIR-HF, CONFIRM-HF and AFFIRM-AHF were matched with those used in IRONMAN. The primary endpoint was recurrent HF hospitalizations and cardiovascular mortality. The analysis of recurrent events was based on rate ratios (RR) derived from the Lin-Wei-Yang-Ying model, and the data were pooled using Bayesian random-effects meta-analysis. Compared with placebo, intravenous iron significantly reduced the rates of recurrent HF hospitalizations and cardiovascular mortality (RR 0.73, 95% credible interval [CI] 0.48-0.99; between-trial heterogeneity tau = 0.16). The pooled treatment effects did not provide evidence for any differential effects for subgroups based on sex (ratio of rate ratios [RRR] 1.49 [95% CI 0.95-2.37], age <69.4 vs. ≥69.4 years) (RRR 0.68 [0.40-1.15]), ischaemic versus non-ischaemic aetiology of HF (RRR 0.73 [0.42-1.33]), transferrin saturation <20% vs. ≥20% (RRR 0.75 [0.40-1.34]), estimated glomerular filtration rate ≤60 versus >60 ml/min/1.73 m2 (RRR 0.97 [0.56-1.68]), haemoglobin <11.8 versus ≥11.8 (RRR 0.95 [0.53-1.60]), ferritin <35 versus ≥35 μg/L (RRR 1.26 [0.72-2.48]) and New York Heart Association class II versus III/IV (RRR 0.91 [0.54-1.56]).

CONCLUSIONS

Treatment of iron-deficient HFrEF patients with intravenous iron - namely with ferric carboxymaltose or ferric derisomaltose - results in significant reduction in recurrent HF hospitalizations and cardiovascular mortality. Results were nominally consistent across the subgroups studied, but for several of these subgroups uncertainty remains present.

Association of myocardial iron deficiency based on T2* CMR with the risk of mild left ventricular dysfunction in HIV-1-infected patients

Objectives

This study sought to noninvasively determine myocardial iron levels in HIV-1-infected patients using CMR and explore the association between T2* values and mild left ventricular systolic dysfunction (LVSD).

Methods

This prospective study was conducted from June 2019 to July 2021. HIV-1-infected adults and healthy controls were consecutively enrolled for CMR exam. CMR exam included the assessment of myocardium iron content (T2*), cardiac function (cine), inflammation (T2), and fibrosis (through extracellular volume fraction [ECV] and late gadolinium enhancement [LGE]) measurements. Mild LVSD is defined as a left ventricular ejection fraction (LVEF) between 40% and 49%.

Results

Of 47 HIV-1-infected patients enrolled, 12 were diagnosed with mild LVSD (HIV-1+/LEVF+) and 35 were diagnosed with preserved LV function (HIV-1+/LEVF-). Compared with healthy controls, HIV-1-infected patients displayed higher T2*, T1, T2, ECV values and lower global circumferential strain (GCS) and global radial strain (GRS) (all P < 0.05). However, between patients with and without mild LVSD, only the T2* values and ECV (all P <0.05) were different. The association between increased T2* values (>26 ms) and mild LVSD remained significant after adjusting for the established univariate predictors (ECV >32.9%, T1 values >1336 ms) of mild LVSD (odds ratio [OR], 10.153; 95% confidence interval [CI] 1.565-65.878, P = 0.015).

Conclusions

Myocardial T2* values were elevated in HIV-1-infected patients, supporting the notion that ID was associated with mild LVSD. Our findings highlight the potential for ID in HIV-1-infected patients as an auxiliary biomarker to monitor the course of LVSD.

Iron Deficiency and Deranged Myocardial Energetics in Heart Failure

Among different pathomechanisms involved in the development of heart failure, adverse metabolic myocardial remodeling closely related to ineffective energy production, constitutes the fundamental feature of the disease and translates into further progression of both cardiac dysfunction and maladaptations occurring within other organs. Being the component of key enzymatic machineries, iron plays a vital role in energy generation and utilization, hence the interest in whether, by correcting systemic and/or cellular deficiency of this micronutrient, we can influence the energetic efficiency of tissues, including the heart. In this review we summarize current knowledge on disturbed energy metabolism in failing hearts as well as we analyze experimental evidence linking iron deficiency with deranged myocardial energetics.

Iron Deficiency in Heart Failure and Pulmonary Hypertension

Purpose of review

To describe the role of iron deficiency in both heart failure and pulmonary hypertension.

Recent findings

To role of iron deficiency in heart failure is well established and pathophysiologic overlap with pulmonary hypertension exists.

Summary

Iron deficiency is common co-morbidity in heart failure and pulmonary hypertension. The high prevalence is intertwined into the pathophysiology of these conditions (e.g., neurohormonal activation, inflammation). The presence of iron deficiency has a negative impact on cardiomyocytes and cardiac function, skeletal muscle function, and pulmonary vascular function. In heart failure data from over 2000 randomized patients with iron deficiency using a uniform diagnosis, have illustrated beneficial effects on functional status, quality of life, reverse cardiac remodeling, and heart failure admissions. While iron deficiency is recognized to be prevalent in pulmonary hypertension and associated with worse functional status, the absence of a uniform definition and the absence of large prospective randomized controlled trials with iron therapies limits the conclusions on the causal role of iron deficiency such as observed in heart failure.

Influence of Iron Deficiency on Clinical and Haemodynamic Parameters in Pulmonary Arterial Hypertension Cohorts

BACKGROUND

Iron deficiency (Fe_def) has been shown to be common in patients with group 1 or pulmonary arterial hypertension (PAH). Several studies have shown a negative impact of Fe_def on clinical and haemodynamic parameters of the disease, but data from individual studies have not been strong enough to lead to incorporation of the finding of Fe_def into prognostic or therapeutic algorithms. The goal of this meta-analysis was to combine data from available studies to better define any associations between Fe_def and established variables of prognostic importance in PAH.

METHODS

A literature search identified nine studies with extractable data relevant to the study questions. The impact of Fe_def upon the following parameters was evaluated: 6-minute walk distance (6MWD), WHO-functional class, N-terminal pro-brain natriuretic peptide (NT-proBNP) levels, echocardiography, and findings from right heart catheterisation (RHC). Pooled results were reported as mean difference or risk difference with 95% confidence intervals utilising a random effects modeling approach.

RESULTS

Fe_def in the PAH population was common (47% of cases) and was associated with cardiovascular dysfunction (lower tricuspid annular plane systolic excursion [TAPSE], elevated NT-proBNP, and lower mixed venous oxygen saturation) and with reduction in functional capacity (lower 6MWD and higher functional class).

CONCLUSION

This meta-analysis strengthens the relationships between Fe_def and several markers of poor outcome in PAH. Fe_def in patients with PAH warrants further scrutiny and merits consideration as a cause of clinical deterioration. Even though causation and longitudinal relationships between Fe_def and PAH could not be identified, effect of Fe_def on factors that affect disease prognosis is noteworthy and worthy of more focussed studies.

Vascular Aging and Damage in Patients with Iron Metabolism Disorders

Vascular aging is a physiological, multifactorial process that involves every type of vessel, from large arteries to microcirculation. This manifests itself as impaired vasomotor function, altered secretory phenotype, deteriorated intercellular transport function, structural remodeling, and aggravated barrier function between the blood and the vascular smooth muscle layer. Iron disorders, particularly iron overload, may lead to oxidative stress and, among other effects, vascular aging. The elevated transferrin saturation and serum iron levels observed in iron overload lead to the formation of a non-transferrin-bound iron (NTBI) fraction with high pro-oxidant activity. NTBI can induce the production of reactive oxygen species (ROS), which induce lipid peroxidation and mediate iron-related damage as the elements of oxidative stress in many tissues, including heart and vessels' mitochondria. However, the available data make it difficult to precisely determine the impact of iron metabolism disorders on vascular aging; therefore, the relationship requires further investigation. Our study aims to present the current state of knowledge on vascular aging in patients with deteriorated 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.

Can Iron Play a Crucial Role in Maintaining Cardiovascular Health in the 21st Century?

In the 21st century the heart is facing more and more challenges so it should be brave and iron to meet these challenges. We are living in the era of the COVID-19 pandemic, population aging, prevalent obesity, diabetes and autoimmune diseases, environmental pollution, mass migrations and new potential pandemic threats. In our article we showed sophisticated and complex regulations of iron metabolism. We discussed the impact of iron metabolism on heart diseases, treatment of heart failure, diabetes and obesity. We faced the problems of constant stress, climate change, environmental pollution, migrations and epidemics and showed that iron is really essential for heart metabolism in the 21st century.

Bioactive nutraceutical ligands and their efficiency to chelate elemental iron of varying dynamic oxidation states to mitigate associated clinical conditions

The natural bioactive or nutraceuticals exhibit several health benefits, including anti-inflammatory, anti-cancer, metal chelation, antiviral, and antimicrobial activity. The inherent limitation of nutraceuticals or bioactive ligand(s) in terms of poor pharmacokinetic and other physicochemical properties affects their overall therapeutic efficiency. The excess of iron in the physiological compartments and its varying dynamic oxidation state [Fe(II) and Fe(III)] precipitates various clinical conditions such as non-transferrin bound iron (NTBI), labile iron pool (LIP), ferroptosis, cancer, etc. Though several natural bioactive ligands are proposed to chelate iron, the efficiency of bioactive ligands is limited due to poor bioavailability, denticity, and other related physicochemical properties. The present review provides insight into the relevance of studying the dynamic oxidation state of iron(II) and iron(III) in the physiological compartments and its clinical significance for selecting diagnostics and therapeutic regimes. We suggested a three-pronged approach, i.e., diagnosis, selection of therapeutic regime (natural bioactive), and integration of novel drug delivery systems (NDDS) or nanotechnology-based principles. This systematic approach improves the overall therapeutic efficiency of natural iron chelators to manage iron overload-related clinical conditions.

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.

Anemia and Heart Failure: A Narrative Review

Anemia in heart failure patients is a relatively common finding and has been linked with an increased risk of hospital admissions, morbidities, and significant mortality making its correction a significant factor in improving the quality of life and clinical outcomes in those suffering from it. This review article has discussed the multifactorial pathophysiology, including iron deficiency, longstanding inflammation, abnormal levels of human erythropoietin (Epo), and the abnormal activation of the renin-angiotensin-aldosterone system (RAAS) being the most significant. The diagnostic guidelines as well as research-based management modalities specifically with iron supplements and erythropoietin stimulating agents have also been discussed, although research done in this area has been limited and shown conflicting results.

Baseline characteristics of 547 new onset heart failure patients in the PREFERS heart failure study

Aim

Methods and results

Conclusions

Identification and Analysis of Hub Genes in Diabetic Cardiomyopathy: Potential Role of Cytochrome P450 1A1 in Mitochondrial Metabolism and STZ-Induced Myocardial Dysfunction

Diabetic cardiomyopathy (DCM) is a primary cause of death in diabetic patients; however, its molecular mechanism is not yet clear, and there is no uniform standard for diagnosis. The aim of this study is to discover the pathogenesis and potential therapeutic targets of DCM through screening and analysis of differentially expressed genes (DEGs) in heart ventricles of DCM, and to testify the role of key hub genes in DCM-induced myocardial dysfunction. Datasets GSE4745 and GSE6880 were downloaded from the GEO database. The difference analysis, visual analysis, cluster analysis and enrichment analysis were performed by using R language, python scripts and bioinformatics software followed by the construction of protein-protein interaction (PPI) network to obtain hub genes. The DCM models were established by streptozocin (STZ) injection to the male mice. The cardiac function and the expressions of hub genes were examined by using echocardiography and real-time quantitative poly-merase chain reaction (RT-qPCR), followed by multiple statistical analyses. Bioinformatic results indicate that mitochondrial dysfunction, disturbed lipid metabolism and decreased collagen synthesis are the main causes of the DCM development. In particular, the hub gene Cyp1a1 that encodes Cytochrome P450 1A1 (CYP4501A1) enzyme has the highest connectivity in the interaction network, and is associated with mitochondrial homeostasis and energy metabolism. It plays a critical role in the oxidation of endogenous or exogenous substrates. Our RT-qPCR results confirmed that ventricular Cyp1a1 mRNA level was nearly 12-fold upregulated in DCM model compared to normal control, which was correlated with abnormal cardiac function in diabetic individuals. CYP4501A1 protein expression in mitochondria was also increased in diabetic hearts. However, we found no significant changes in collagen expressions in cardiac ventricles of mice with DCM. This study provided compact data support for understanding the pathogenesis of DCM. CYP4501A1 might be considered as a potential candidate targeting for DCM therapy. Follow-up animal and clinical verifications need to be further explored.

The effect of Intravenous ferric-carboxymaltose on right ventricular function - insights from the IRON-CRT trial

BACKGROUND

Ferric carboxymaltose (FCM) improves left ventricular (LV) function in heart failure with reduced ejection fraction (HFrEF). Yet, the effect of FCM on right ventricular (RV) function remains insufficiently elucidated.

METHODS

This is a predefined analysis of the IRON-CRT trial in which symptomatic HFrEF patients with iron deficiency and reduced LV ejection (LVEF) despite optimal medical therapy and cardiac resynchronization therapy (CRT) underwent 1:1-randomization to FCM or placebo in a double blind fashion. RV function was measured as the change from baseline to 3-month follow-up of RV fractional area change (FAC), TAPSE and RV S', systolic pulmonary artery pressure (SPAP) and its coupling to the RV (TAPSE/SPAP-ratio). The RV-contractile reserve was measured as the change in TAPSE during incremental pacing at 70, 90 and 110 Bpm.

RESULTS

A total of 75 patients underwent randomization and received FCM(n= 37) or placebo(n=38). At baseline 72.5% had RV dysfunction and 70% had RV dilatation. At 3-month follow-up patients receiving FCM had a significant improvement in RV FAC (Placebo=-2.2%[-4.9%-+0.6%] vs FCM=+4.1%[+1.4%-+6.9%], p=0.002) and TAPSE (placebo=-0.19mm[-0.85mm-+0.48mm] vs FCM=+0.98mm[+0.28mm-+1.62mm], p=0.020), but not RV S'. Patients receiving FCM had a numerically lower SPAP (p=0.073) and significant improvement in TAPSE/SPAP-ratio (placebo= +0.002[-0.046-+0.051] vs FCM= +0.097[+0.048-+0.146], p=0.008). At baseline both groups had diminished RV-contractile reserve during incremental pacing, which was attenuated at 3-month follow-up in the FCM group (p=0.004). Patients manifesting more RV function improvement were more likely to exhibit higher degrees of LVEF-improvement (p<0.05 for all).

CONCLUSIONS

Treatment with FCM in HFrEF patients results in an improvement in RV function and structure and improves the RV-contractile reserve.

The Effect of Iron Deficiency on Cardiac Function and Structure in Heart Failure with Reduced Ejection Fraction

Over the past decade, the detrimental impact of iron deficiency in heart failure with reduced ejection fraction has become abundantly clear, showing a negative impact on functional status, quality of life, cardiac function and structure, exercise capacity and an increased risk of hospitalisation due to heart failure. Mechanistic studies have shown the impact of iron deficiency in altering mitochondrial function and negatively affecting the already altered cardiac energetics in heart failure with reduced ejection fraction. Such failing energetics form the basis of the alterations to cellular myocyte shortening, culminating in reduced systolic function and cardiac performance. The IRON-CRT trials show that ferric carboxymaltose is capable of improving cardiac structure and cardiac performance. This article discusses the effect of iron deficiency on cardiac function and structure and how it can be alleviated.

Deficiência de Ferro na Insuficiência Cardíaca com Fração de Ejeção Reduzida: Fisiopatologia, Diagnóstico e Tratamento

A deficiência de ferro (DF) ou ferropenia é uma importante comorbidade na insuficiência cardíaca com fração de ejeção reduzida (ICFER) estável, e muito prevalente tanto nos anêmicos como não anêmicos. A ferropenia na ICFER deve ser pesquisada por meio da coleta de saturação de transferrina e ferritina. Há dois tipos de ferropenia na IC: absoluta, em que as reservas de ferro estão depletadas; e funcional, onde o suprimento de ferro é inadequado apesar das reservas normais. A ferropenia está associada com pior classe funcional e maior risco de morte em pacientes com ICFER, e evidências científicas apontam melhora de sintomas e de qualidade de vida desses pacientes com tratamento com ferro parenteral na forma de carboximaltose férrica. O ferro exerce funções imprescindíveis como o transporte (hemoglobina) e armazenamento (mioglobina) de oxigênio, além de ser fundamental para o funcionamento das mitocôndrias, constituídas de proteínas à base de ferro, e local de geração de energia na cadeia respiratória pelo metabolismo oxidativo. A geração insuficiente e utilização anormal de ferro nas células musculares esquelética e cardíaca contribuem para a fisiopatologia da IC. A presente revisão tem o objetivo de aprofundar o conhecimento a respeito da fisiopatologia da ferropenia na ICFER, abordar as ferramentas disponíveis para o diagnóstico e discutir sobre a evidência científica existente de reposição de ferro.

Prevalence and determinants of iron deficiency in cardiac amyloidosis

Aims

Iron deficiency (ID) is common in patient with chronic heart failure (HF) and has been widely studied. In contrast, data concerning ID in cardiac amyloidosis (CA) are limited. Amyloidosis is a severe and fatal systemic disease, characterized by an accumulation of amyloid fibrils in various tissues/organs, including nerves, kidneys, gastrointestinal tract, and heart. Amyloid deposits in the heart eventually cause HF. The main subtypes of CA are light chain (AL), hereditary transthyretin (ATTRv), and wild‐type transthyretin (ATTRwt). We performed this study to determine the prevalence, clinical outcome (all‐cause mortality), and determinants of ID among the three main subtypes of CA.

Methods and results

Iron deficiency status were analysed in 816 CA patients enrolled at the French Referral Centre for Cardiac Amyloidosis: 271 (33%) had AL, 164 (20%) ATTRv, and 381 (47%) ATTRwt. ID affected 49% of CA patients, 45% with AL, 58% with ATTRv, and 48% with ATTRwt. We identified ATTR status (ATTRv P = 0.003, ATTRwt P = 0.037), diabetes (P = 0.003), aspirin treatment (P = 0.009), haemoglobin levels (P = 0.006), and altered global longitudinal strain (P = 0.02) as independent ID determinants. There is no difference in all‐cause mortality considering ID status.

Conclusions

Iron deficiency is common in patients with CA, irrespective of the subtype. Patients seem more likely to have ID if diagnosed with ATTR, if diabetic, and/or treated with aspirin. In CA, the benefit of intravenous iron therapy, for ID, on morbidity and mortality needs further study.

Chronic Heart Failure: Clinical Implications of Iron Homeostasis Disturbances Revisited

Iron deficiency is prevalent in chronic heart failure (CHF) patients. Nonetheless, the diagnosis is often overlooked and, often, the treatment is commenced just when overt anemia has ensued. Therefore, a better appreciation of this disease is needed, and all seasoned cardiologists should know how to approach CHF patients with iron deficiency correctly, as mandated by clinical practice guidelines. In this comprehensive review, we describe iron homeostasis, the pathophysiologic changes of iron homeostasis, and the clinical implications of iron deficiency on CHF patients. In addition, we delineate the evolution of clinical trials, ranging from the inception to the ongoing clinical trials of iron deficiency treatment in CHF patients. Iron deficiency contributes to the worse clinical outcome of the patients. Numerous studies have reported the clinical benefit of iron supplementation, particularly in intravenous preparation, in heart failure patients regarding symptoms, functional capacity, and quality of life (QoL) improvement. Therefore, the current guidelines recommend routine screening of iron status in all newly diagnosed heart failure patients. Eventually, intravenous iron replacement is recommended for symptomatic heart failure patients with iron deficiency, irrespective of anemia.

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.

Ferric carboxymaltose in patients with pulmonary arterial hypertension and iron deficiency: a long-term study

BACKGROUND

Pulmonary arterial hypertension (PAH) is a progressive disease with limited survival. Iron deficiency (ID) correlates with disease severity and mortality. While oral iron supplementation was shown to be insufficient in such patients, the potential impact of parenteral iron on clinical measures warrants further investigation.

METHODS

We retrospectively analysed the long-term effects of intravenous ferric carboxymaltose (FCM) on iron status and clinical measures in patients with PAH and ID [ferritin < 100 μg/L or ferritin 100-300 μg/L and transferrin saturation (TSAT) < 20%] who were on stable targeted PAH therapy, compared with matched controls without ID. Patients with ID received a single infusion of FCM (500 to 1000 mg). Clinical measures monitored included exercise capacity, World Health Organization (WHO) functional class, ESC/ERS risk status, and hospitalizations. The observation period was up to 18 months.

RESULTS

One hundred and seventeen patients (mean age 60.9 ± 16.1 years; 64.1% females) with confirmed PAH and on stable targeted therapy for ≥3 months were included (58 with and 59 patients without ID who did not receive FCM). In patients with ID, iron supplementation with FCM resulted in an immediate and sustained improvement of iron status for up to 18 months (serum iron, ferritin, TSAT, all P < 0.01). Fourteen patients in the FCM group received a second FCM infusion after 9.6 ± 4.8 months due to recurrent ID. At 6 and 18 months after FCM infusion, 6 min walk distance improved from 377.5 ± 15.9 at baseline to 412.5 ± 15.1 and 400.8 ± 14.5 m, respectively (both P < 0.05). WHO functional class (P < 0.05) and ESC/ERS risk status also improved, and there was a reduction of hospitalizations for worsening PAH in the 12 months post vs. prior to iron repletion (P = 0.029). No significant changes were observed in the control group. FCM was well tolerated in all patients, with no severe adverse events.

CONCLUSIONS

In addition to targeted therapy, correction of ID by parenteral iron supplementation with FCM appears feasible and safe, has sustained effects on iron status, and may improve the clinical status and hospitalization rates in patients with PAH. Larger controlled studies are required to confirm this finding.

Implications of Iron Deficiency in STEMI Patients and in a Murine Model of Myocardial Infarction

•

In patients with STEMI treated with primary percutaneous coronary intervention, iron deficiency is associated with larger infarcts, more extensive microvascular obstruction, and a higher frequency of adverse left ventricular remodeling.

•

An iron-deficient diet reduces the tolerance to ischemia/reperfusion in mice at least in part by interfering with the cardioprotective pathway eNOS/soluble guanylate cyclase/protein kinase G.

•

An iron-deficient diet reduces eNOS activity by increasing oxidative/nitrosative stress and its proteasome-dependent degradation.

•

Not only iron excess but also iron deficiency may have deleterious effects in the context of acute myocardial ischemia.

In patients with a first anterior ST-segment elevation myocardial infarction treated with primary percutaneous coronary intervention, iron deficiency (ID) was associated with larger infarcts, more extensive microvascular obstruction, and higher frequency of adverse left ventricular remodeling as assessed by cardiac magnetic resonance imaging. In mice, an ID diet reduced the activity of the endothelial nitric oxide synthase/soluble guanylate cyclase/protein kinase G pathway in association with oxidative/nitrosative stress and increased infarct size after transient coronary occlusion. Iron supplementation or administration of an sGC activator before ischemia prevented the effects of the ID diet in mice. Not only iron excess, but also ID, may have deleterious effects in the setting of ischemia and reperfusion.

Ferritinophagy and ferroptosis in cardiovascular disease: Mechanisms and potential applications

Ferroptosis is a type of regulated cell death driven by iron dependent accumulation of cellular reactive oxygen species (ROS) when glutathione (GSH)-dependent lipid peroxidation repair systems are compromised. Nuclear receptor co-activator 4 (NCOA4)-mediated selective autophagy of ferritin, termed ferritinophagy, involves the regulation of ferroptosis. Emerging evidence has revealed that ferritinophagy and ferroptosis exert a significant role in the occurrence and development of cardiovascular disease. In the present review, we aimed to present a brief overview of ferritinophagy and ferroptosis focusing on the underlying mechanism and regulations involved. We summarize and discuss relevant research progress on the role of ferritinophagy and ferroptosis in cardiovascular diseases accompanied with potential applications of ferritinophagy and ferroptosis modulators in the treatment of ferroptosis-associated cardiovascular diseases.

Ultrastructural aberrations, histological disruption and upregulation of the VEGF, CD34 and ASMA immunoexpression in the myocardium of anemic albino rats

Iron deficiency anemia (IDA) is a global health problem affecting various body systems and tissues including the cardiovascular system. Several literatures described the associated physiological and clinical changes in the cardiovascular system and heart. However, the associated structural changes were poorly investigated. Therefore, the main aim of the present work was to elucidate whether IDA induces structural changes and alterations in the VEGF, CD34 and ASMA immunoexpression in the myocardium of albino rats. Thirty adult male albino rats were divided into two groups (fifteen rats each); control and anemic. Hematological data for all animals were assessed weekly and statistically analyzed. Three weeks later, animals were sacrificed, and heart specimens were obtained and processed for light and electron microscopy. All hematological parameters showed a statistically significant decrease in the anemic group. Structurally, the anemic group showed markedly degenerated, disrupted and disorganized cardiomyocytes in addition to markedly congested blood vessels, fibroblasts, collagen fibers deposition and perivascular cellular infiltration were noted. Also, positive immunostaining for VEGF, CD34 and ASMA was observed. Ultra-structurally, the myocardium of the anemic group showed disrupted and degenerated myofibrils with degenerated nuclei, perinuclear edema, widened interstitial spaces and marked collagen deposition. Mitochondria markedly increased with abnormal shapes. IDA induced myocardial injury that may propagate to regeneration through activated CD34 progenitor cells and increased VEGF or to degeneration and fibrosis through collagen fibers deposition and enhanced ASMA. So, early diagnosis and treatment of IDA is mandatory to avoid the associated myocardial structural changes.

The effect of intravenous ferric carboxymaltose on cardiac reverse remodelling following cardiac resynchronization therapy-the IRON-CRT trial

Aims

Iron deficiency is common in heart failure with reduced ejection fraction (HFrEF) and negatively affects cardiac function and structure. The study the effect of ferric carboxymaltose (FCM) on cardiac reverse remodelling and contractile status in HFrEF.

Methods and results

Symptomatic HFrEF patients with iron deficiency and a persistently reduced left ventricular ejection fraction (LVEF <45%) at least 6 months after cardiac resynchronization therapy (CRT) implant were prospectively randomized to FCM or standard of care (SOC) in a double-blind manner. The primary endpoint was the change in LVEF from baseline to 3-month follow-up assessed by three-dimensional echocardiography. Secondary endpoints included the change in left ventricular end-systolic (LVESV) and end-diastolic volume (LVEDV) from baseline to 3-month follow-up. Cardiac performance was evaluated by the force–frequency relationship as assessed by the slope change of the cardiac contractility index (CCI = systolic blood pressure/LVESV index) at 70, 90, and 110 beats of biventricular pacing. A total of 75 patients were randomized to FCM (n = 37) or SOC (n = 38). At baseline, both treatment groups were well matched including baseline LVEF (34 ± 7 vs. 33 ± 8, P = 0.411). After 3 months, the change in LVEF was significantly higher in the FMC group [+4.22%, 95% confidence interval (CI) +3.05%; +5.38%] than in the SOC group (−0.23%, 95% CI −1.44%; +0.97%; P < 0.001). Similarly, LVESV (−9.72 mL, 95% CI −13.5 mL; −5.93 mL vs. −1.83 mL, 95% CI −5.7 mL; 2.1 mL; P = 0.001), but not LVEDV (P = 0.748), improved in the FCM vs. the SOC group. At baseline, both treatment groups demonstrated a negative force–frequency relationship, as defined by a decrease in CCI at higher heart rates (negative slope). FCM resulted in an improvement in the CCI slope during incremental biventricular pacing, with a positive force–frequency relationship at 3 months. Functional status and exercise capacity, as measured by the Kansas City Cardiomyopathy Questionnaire and peak oxygen consumption, were improved by FCM.

Conclusions

Treatment with FCM in HFrEF patients with iron deficiency and persistently reduced LVEF after CRT results in an improvement of cardiac function measured by LVEF, LVESV, and cardiac force–frequency relationship.

Dysregulation of iron metabolism in cardiovascular diseases: From iron deficiency to iron overload

Iron deficiency and iron overload are the most prevalent and opposite forms of dysregulated iron metabolism that affect approximately 30 percent of the world population, in particularly, elderly and patients with chronic diseases. Both iron deficiency and overload are frequently observed in a wide range of cardiovascular diseases, contributing to the onset and progression of these diseases. One of the devastating seqeulae for iron overload is the induction of ferroptosis, a newly defined form of regulated cell death which heavily impacts cardiac function through ferroptotic cell death in cardiomyocytes. In this review, we will aim to evaluate iron deficiency and iron overload in cardiovascular diseases. We will summarize current therapeutic strategies to tackle iron deficiency and iron overload, major pitfalls of current studies, and future perspectives.

Pathophysiology and Therapeutic Approaches to Acute Decompensated Heart Failure

Acute decompensated heart failure (ADHF) is one of the leading admission diagnoses worldwide, yet it is an entity with incompletely understood pathophysiology and limited therapeutic options. Patients admitted for ADHF have high in-hospital morbidity and mortality, as well as frequent rehospitalizations and subsequent cardiovascular death. This devastating clinical course is partly due to suboptimal medical management of ADHF with persistent congestion upon hospital discharge and inadequate predischarge initiation of life-saving guideline-directed therapies. While new drugs for the treatment of chronic HF continue to be approved, there has been no new therapy approved for ADHF in decades. This review will focus on the current limited understanding of ADHF pathophysiology, possible therapeutic targets, and current limitations in expanding available therapies in light of the unmet need among these high-risk patients.

Immunoadsorption for heart failure is associated with normalization of iron metabolism

AIMS

In heart failure (HF) patients, early stages are associated with increased iron levels, whereas iron deficiency is a common feature of chronic HF. We investigated the acute and long-term changes in iron metabolism in HF patients after immunoadsorption treatment and intravenous immunoglobulin (IVIG) administration.

METHODS AND RESULTS

Twenty-seven patients with HF with reduced ejection fraction (HFrEF) received a single cycle of immunoadsorption followed by IVIG administration. Left ventricular ejection fraction (LVEF) and iron biomarker (ferritin, hepcidin and interleukin-6) were evaluated at baseline, after immunoadsorption and during long-term follow-up of 29.3 months. LVEF improved significantly after immunoadsorption treatment from baseline 27% to 43% at long-term follow-up. Ferritin decreased from baseline 300.2 to 201.3 ng/mL (p < 0.0001) during immunoadsorption treatment and normalized during long-term to 207.9 ng/mL. Hepcidin showed a V-shaped course, with a significant decrease after immunoadsorption and normalization during long-term. Interleukin-6 levels showed no relevant inflammation.

CONCLUSIONS

Our data suggest that initial high serum ferritin and hepcidin levels indicate elevated iron levels characteristic of early stages of HFrEF, without inflammation. Normalization of hepcidin and ferritin was paralleled by restoration of systolic cardiac function after immunoadsorption treatment, without development of iron deficiency, as usually observed in chronic HF.

Intravenous iron therapy and the cardiovascular system: risks and benefits

Anaemia is a common complication of chronic kidney disease (CKD). In this setting, iron deficiency is frequent because of the combination of increased iron needs to sustain erythropoiesis with increased iron losses. Over the years, evidence has accumulated on the involvement of iron in influencing pulmonary vascular resistance, endothelial function, atherosclerosis progression and infection risk. For decades, iron therapy has been the mainstay of therapy for renal anaemia together with erythropoiesis-stimulating agents (ESAs). Despite its long-standing use, grey areas still surround the use of iron therapy in CKD. In particular, the right balance between either iron repletion with adequate therapy and the avoidance of iron overload and its possible negative effects is still a matter of debate. This is particularly true in patients having functional iron deficiency. The recent Proactive IV Iron Therapy in Haemodialysis Patients trial supports the use of intravenous (IV) iron therapy until a ferritin upper limit of 700 ng/mL is reached in haemodialysis patients on ESA therapy, with short dialysis vintage and minimal signs of inflammation. IV iron therapy has also been proven to be effective in the setting of heart failure (HF), where it improves exercise capacity and quality of life and possibly reduces the risk of HF hospitalizations and cardiovascular deaths. In this review we discuss the risks of functional iron deficiency and the possible benefits and risks of iron therapy for the cardiovascular system in the light of old and new evidence.

Iron Deficiency without Anemia Decreases Physical Endurance and Mitochondrial Complex I Activity of Oxidative Skeletal Muscle in the Mouse

Iron deficiency (ID), with or without anemia, is responsible for physical fatigue. This effect may be linked to an alteration of mitochondrial metabolism. Our aim was to assess the impact of ID on skeletal striated muscle mitochondrial metabolism. Iron-deficient non-anemic mice, obtained using a bloodletting followed by a low-iron diet for three weeks, were compared to control mice. Endurance was assessed using a one-hour submaximal exercise on a Rotarod device and activities of mitochondrial complexes I and IV were measured by spectrophotometry on two types of skeletal striated muscles, the soleus and the quadriceps. As expected, ID mice displayed hematologic markers of ID and reduced iron stores, although none of them were anemic. In ID mice, endurance was significantly reduced and activity of the respiratory chain complex I, normalized to citrate synthase activity, was significantly reduced in the soleus muscle but not in the quadriceps. Complex IV activities were not significantly different, neither in the soleus nor in the quadriceps. We conclude that ID without anemia is responsible for impaired mitochondrial complex I activity in skeletal muscles with predominant oxidative metabolism. These results bring pathophysiological support to explain the improved physical activity observed when correcting ID in human. Further studies are needed to explore the mechanisms underlying this decrease in complex I activity and to assess the role of iron therapy on muscle mitochondrial metabolism.

How I treat anemia in heart failure

Anemia is a very common comorbidity in patients with heart failure (HF), affecting ∼30% of stable ambulatory patients and 50% patients with acute decompensated HF. Absolute or functional iron deficiency (ID) is seen in ∼50% patients with HF. Both of these comorbidities often coexist and are independently associated with increased mortality and hospitalizations. These findings led several investigators to test the hypotheses that treatment of anemia and ID in HF would improve symptoms and long-term outcomes. Small studies showed that erythropoiesis-stimulating agents (ESAs) improve subjective measures of HF. However, a large pivotal outcome trial found that the ESA darbepoetin alfa did not improve long-term outcomes in patients with HF with reduced ejection fraction and instead was associated with adverse effects. Studies using IV iron have had somewhat greater success, showing improvements in subjective and some objective measures of HF. However, more research is needed to establish the best treatment options for these high-risk patients. We present 5 common scenarios of patients with HF and anemia and describe our personal approach on how we might treat them based on objective evidence where available. An algorithm that offers guidance in regard to personalized therapy for such patients is also presented.

The utility of electrocardiography and echocardiography in copper deficiency-induced cardiac damage in goats

Copper deficiency (CuD) is a common mineral disorder in ruminants, which causes histomorphological changes in the heart due to disturbances in copper-dependent metalloenzymes. However, alterations in the measurable cardiac parameters during CuD have not been studied in ruminants, especially in goats. Therefore, the current study aimed to investigate longitudinally the potential role of electrocardiography (ECG) and echocardiography to detect the CuD-induced cardiac damage at different time intervals and concomitantly highlighting the impact of CuD on specific hemato-biochemical parameters and histological cardiac disruption in goats. Eight Shiba goats were included and divided into two equal groups; copper adequate (CuA) as a control and copper-deficient (CuD) that supplemented with copper-chelating agents (sulfur 3 g/kg DM and molybdenum 40 mg/kg DM). The hemato-biochemical analysis, ECG assessment at the base apex lead, and right-side echocardiography were performed just before the experimental onset (T0), and later on at two-time intervals after existing of CuD, at the fifth (T5) and seventh (T7) months. Necropsy and histopathological examination of the heart were performed at the end of the experiment. In the CuD group, the heart dimensions at T5 and T7 showed significant increase in QRS duration, ST-segment duration, the left atrial area in systole, left ventricular diameter and volume in diastole, stroke volume, and cardiac output compared with CuA (P < 0.05). Also, myocardial degeneration, necrosis, and fibrosis were evidenced with a concurrent increase of plasma creatine kinase, lactate dehydrogenase, aspartate aminotransferase, and cardiac troponin I (P < 0.05). In conclusion, CuD disturbs hemato-biochemical parameters and results in myocardial damage and cardiac dilatation that increases some ECG and echocardiographic parameters without development of systolic dysfunction. The ECG and echocardiography can potentially detect cardiac changes in long-lasting CuD in goats.

Right ventricular function and iron deficiency in acute heart failure

AIMS

Iron deficiency (ID) is a frequent finding in patients with chronic and acute heart failure (AHF) along the full spectrum of left ventricular ejection fraction (LVEF). Iron deficiency has been related to ventricular systolic dysfunction, but its role in right ventricular function has not been evaluated. We sought to evaluate whether ID identifies patients with greater right ventricular dysfunction in the setting of AHF.

METHODS AND RESULTS

We prospectively included 903 patients admitted with AHF. Right systolic function was evaluated by tricuspid annular plane systolic excursion (TAPSE) and the ratio TAPSE/pulmonary artery systolic pressure (TAPSE/PASP). Iron deficiency was defined, according to European Society of Cardiology criteria, as serum ferritin <100 mg/dL (absolute ID) or ferritin 100-299 mg/dL and transferrin saturation (TSAT) <20% (functional ID). The relationships among the exposures with right ventricular systolic function were evaluated by multivariate linear regression analyses. The mean age of the sample was 74.3 ± 10.6 years, 441 (48.8%) were female, 471 (52.2%) exhibited heart failure with preserved ejection fraction, and 677 (75.0%) showed ID. The mean LVEF, TAPSE, and TAPSE/PASP were 49 ± 15%, 18.6 ± 3.9 mm, and 0.45 ± 0.18, respectively. The median (interquartile range) amino-terminal pro-brain natriuretic peptide was 4015 (1807-8775) pg/mL. In a multivariable setting, lower TSAT and ferritin were independently associated with lower TAPSE (P < 0.05 for both comparisons). Transferrin saturation (P = 0.017), and not ferritin (P = 0.633), was independently associated with TAPSE/PASP.

CONCLUSION

In AHF, proxies of ID were associated with right ventricular dysfunction. Further studies should confirm these findings and evaluate the pathophysiological facts behind this association.

Selegiline acts as neuroprotective agent against methamphetamine-prompted mood and cognitive related behavior and neurotoxicity in rats: Involvement of CREB/BDNF and Akt/GSK3 signal pathways

Objective(s):

Present study investigated the neuroprotective effects of selegiline and the molecular mechanisms involved in methamphetamine-induced neurotoxicity.

Materials and Methods:

Male wistar rats were randomly divided into six groups (10 rats in each group). Group 1 and group 2 received normal saline and methamphetamine (10 mg/kg), respectively. Groups 3, 4, 5 and 6 were treated simultaneously with methamphetamine and selegiline. From day 22 to day 28, forced swim test, elevated plus maze, and open field test were conducted to assess mood (anxiety and depression) levels, and from day 17 to day 21, Morris Water Maze was conducted for cognition assessment. On day 29, hippocampus of the animals were isolated and evaluated by ELISA method for oxidative, antioxidant, and inflammatory factors and expression levels of active (total) and inactive (phosphorylated) forms of cyclic AMP response element binding protein (CREB), brain-derived neurotrophic factor (BDNF), Akt (Protein Kinase B) and glycogen synthase kinase 3 (GSK3) proteins.

Results:

Selegiline reduced behavioral impacts caused by methamphetamine in all doses. Methamphetamine administration may improve malondialdehyde, tumor necrosis factor-alpha, interleukin-1 beta and GSK3 (both forms). Moreover, methamphetamine reduced the activity of superoxide dismutase, glutathione peroxidase, glutathione reductase, amount of BDNF, CREB and Akt (both forms).

Conclusion:

Current research showed that selegiline can protect the brain from methamphetamine-prompted neurodegeneration, and this could be intervened by CREB -BDNF or Akt-GSK3 signaling pathways.

Clinical, Demographic, and Imaging Correlates of Anemia in Heart Failure With Preserved Ejection Fraction (from the RELAX Trial)

Anemia is a commonly occurring comorbidity among patients of heart failure with preserved ejection fraction (HFpEF) but limited data exists on the cardiovascular phenotype of anemia in HFpEF. We sought to characterize the clinical features, exercise capacity, and outcomes in patients with HFpEF to elucidate the phenotype and pathophysiology of anemia in HFpEF. Post hoc analyses of participants enrolled in the RELAX (Phosphodiesterase-5 Inhibition to Improve Clinical Status and Exercise Capacity in Diastolic Heart Failure) trial was performed. Anemia was defined as hemoglobin <13 g/dL in men and <12 g/dL in women. Multivariate adjusted regression modeling was done to assess for differences in peak oxygen uptake. Adjusted hazard ratios were generated to assess difference in hospitalization events using a Cox proportional hazards model. Anemic HFpEF patients were more likely to be older, male, and have worse renal function (p <0.05 for all). N-terminal pro-B-type natriuretic peptide, troponin I, pro-collagen III N-terminal peptide, C-telopeptide for type I collagen, uric acid, cystatin-c, and galectin-3 (p <0.05 for all) levels were higher in anemic HFpEF patients. In adjusted models, anemic HFpEF patients had worse exercise capacity (peak oxygen uptake: 11.3 vs 12.1 mL/kg/min; p = 0.004). The hazard for cardiac or renal cause of hospitalization in those with anemia was 2.0 (95% confidence interval: 0.9 to 4.3). Anemic HFpEF patients have worse exercise capacity and are more likely to be hospitalized. A better understanding of the physiologic phenotypes of HFpEF patients may allow for greater personalization of treatment and prognostication in HFpEF patients.

Structural and functional abnormalities in iron-depleted heart

Iron deficiency (ID) is a common and ominous comorbidity in heart failure (HF) and predicts worse outcomes, independently of the presence of anaemia. Accumulated data from animal models of systemic ID suggest that ID is associated with several functional and structural abnormalities of the heart. However, the exact role of myocardial iron deficiency irrespective of systemic ID and/or anaemia has been elusive. Recently, several transgenic models of cardiac-specific ID have been developed to investigate the influence of ID on cardiac tissue. In this review, we discuss structural and functional cardiac consequences of ID in these models and summarize data from clinical studies. Moreover, the beneficial effects of intravenous iron supplementation are specified.