Impaired expression of duodenal iron transporters in Dahl salt-sensitive heart failure rats

Iron homeostasis, recycling and vulnerability in the stressed kidney: A neglected dimension of iron-deficient heart failure

The available evidence suggests that the kidney may contribute importantly to the development of an iron deficiency state in patients with heart failure and may be injured by therapeutic efforts to achieve iron repletion. The exceptional workload of the proximal renal tubule requires substantial quantities of iron for ATP synthesis, which it derives from Fe3+ bound to transferrin in the bloodstream. Following ferrireduction, Fe2+ is conveyed by divalent transporters (e.g. DMT1) out of the endosome of the proximal renal tubule, and highly reactive Fe2+ can be directed to the mitochondria, sequestered safely in a ferritin nanocage or exported through the actions of hepcidin-inhibitable ferroportin. The actions of ferroportin, together with transferrin endocytosis and DMT1-mediated transport, play a key role in the recycling of iron from the tubular fluid into the bloodstream and preventing the loss of filtered iron in the urine. Activation of endogenous neurohormonal systems and proinflammatory signalling in heart failure decrease megalin-mediated uptake and DMT1 expression, and increase hepcidin-mediated suppression of ferroportin, promoting the loss of iron in the urine and contributing to the development of an iron deficiency state. Furthermore, the failure of ferroportin-mediated efflux at the basolateral membrane heightens the susceptibility of the renal tubules to cytosolic excesses of Fe2+, causing lipid peroxidation and synchronized cell death (ferroptosis) through the iron-dependent free radical theft of electrons from lipids in the cell membrane. Ferroptosis is a central mechanism to most disorders that can cause acute and chronic kidney disease. Short-term bolus administration of intravenous iron can cause oxidative stress and is accompanied by markers of renal injury. Experimentally, long-term maintenance of an iron-replete state is accompanied by accelerated loss of nephrons, oxidative stress, inflammation and fibrosis. Intravenous iron therapy increases glomerular filtration rate rapidly in patients with heart failure (perhaps because of a haemodynamic effect) but not in patients with chronic kidney disease, and the effects of intravenous iron on the progression of renal dysfunction in the long-term trials - AFFIRM-AHF, IRONMAN and HEART-FID - have not yet been reported. Given the potential role of dysregulated renal iron homeostasis in the pathogenesis of iron deficiency and the known vulnerability of the kidney to intravenous iron, the appropriate level of iron repletion with respect to the risk of acute and chronic kidney injury in patients with heart failure requires further study.

Hypoxia-inducible factor-prolyl hydroxylase inhibitor Roxadustat (FG-4592) reduces renal fibrosis in Dahl salt-sensitive rats

OBJECTIVE

Although hypoxia-inducible factor-prolyl hydroxylase (HIF-PH) inhibitors have been developed for the treatment of renal anemia, their effects on cardiac and renal dysfunction remain unknown. We previously reported on Dahl salt-sensitive rats, in a rat model of salt-sensitive hypertension, that exhibited anemia and impaired expression of duodenal iron transporters after the development of hypertensive cardiac and renal dysfunction. Therefore, we investigated the effects of Roxadustat (FG-4592), an HIF-PH inhibitor, on anemia, iron regulation, and cardiac and renal dysfunction in Dahl salt-sensitive rats.

METHODS

Six-week-old male Dahl salt-sensitive rats were fed a normal or high-salt diet for 8 weeks. A further subset of Dahl salt-sensitive rats, that were fed a high-salt diet, was administered Roxadustat for 8 weeks.

RESULTS

Dahl salt-sensitive rats fed a high-salt diet developed hypertension, cardiac and renal dysfunction, and anemia after 8 weeks of feeding. Roxadustat increased hemoglobin and serum erythropoietin levels in Dahl salt-sensitive rats fed a high-salt diet. With regard to the iron-regulating system, Roxadustat lowered hepatic hepcidin gene expression and increased the gene expression of duodenal iron transporters, such as cytochrome b and divalent metal transporter 1 , in Dahl salt-sensitive rats fed a high-salt diet. Roxadustat did not affect the development of hypertension and cardiac hypertrophy in Dahl salt-sensitive rats with a high-salt diet; however, Roxadustat treatment attenuated renal fibrosis in these rats.

CONCLUSIONS

Roxadustat ameliorated anemia with affecting the gene expression of the iron-regulating system, and did not affect cardiac hypertrophy but attenuated renal fibrosis in Dahl salt-sensitive rats fed a high-salt diet.

Iron Deficiency in Korean Patients With Heart Failure

BACKGROUND

Although iron deficiency (ID) is an important and treatable risk factor for heart failure (HF), data on ID are scarce in Asian patients with HF. Therefore, we sought to determine the prevalence and clinical characteristics of ID in hospitalized Korean patients with HF.

METHODS

In this prospective, multicenter cohort study, 461 patients with acute HF seen at five tertiary centers from January to November 2019 in Korea were enrolled. ID was defined as serum ferritin < 100 μg/L or ferritin 100-299 μg/L in combination with transferrin saturation < 20%.

RESULTS

The patients' mean age was 67.6 ± 14.9 years, and 61.8% were male. Among total 461 patients, ID was present in 248 patients (53.8%). The prevalence of ID was significantly higher in women than in men (65.3% vs. 47.3%, P < 0.001). In a multivariable logistic regression analysis, the independent predictors of ID were female sex (odds ratio [OR], 2.19; 95% confidence interval [CI], 1.47-3.30), valvular heart disease (OR, 2.10; 95% CI, 1.10-4.17), higher heart rate (OR, 1.10; 95% CI, 1.01-1.21), anemia (OR, 1.60; 95% CI, 1.07-2.40), and the use of clopidogrel (OR, 1.56; 95% CI, 1.00-2.45). Among women, the prevalence of ID did not significantly differ between younger and older women (< 65 years: 73.7% vs. ≥ 65 years: 63.0%, P = 0.222), those with low and high body mass index (BMI < 25 kg/m²: 66.2% vs. BMI ≥ 25 kg/m²: 69.6%, P = 0.703), or those with low and high natriuretic peptide (NP) levels (NP < median: 69.8% vs. NP ≥ median: 61.1%, P = 0.295). Only 0.2% patients with acute HF received intravenous iron supplementation in Korea.

CONCLUSION

The prevalence of ID is high in hospitalized Korean patients with HF. Because ID cannot be diagnosed by clinical parameters, routine laboratory examinations are necessary to identify patients with ID.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT04812873.

Is the Benefit of Treating Iron Deficiency Greater in Acute Heart Failure with Renal Dysfunction?

BACKGROUND

This study aims to analyse whether in acute heart failure (AHF) with iron deficiency (ID), the administration of ferric carboxymaltose (FCM) produces a greater benefit in renal dysfunction.

METHODS

A total of 812 consecutive patients admitted for AHF and ID were studied. Untreated (n:272) and treated (n:540) patients were compared. The six-month prevalence of a combined event (readmission for HF, all-cause death, and emergency department visit for decompensation) was analysed. Three grades of renal dysfunction (KDIGO) were compared, Group 1 (grades 1 and 2), Group 2 (grades 3a and 3b), and Group 3 (grades 4 and 5).

RESULTS

There were differences in sex distribution (untreated group: males 39.7% vs. treated group: males 51.9%; p < 0.001). Sex-adjusted combined event analysis showed a greater benefit in Group 1 (OR: 0.31, 95% CI:0.19-0.5; p < 0.001) and Group 2 (OR: 0.23, 95% CI:0.14-0.38; p < 0.001), but not in Group 3 (OR: 0.51, 95% CI:0.17-0.55; p: 0.237).

CONCLUSIONS

The administration of FCM in patients with AHF and ID reduces the combined event analysed. The benefit is greater when renal dysfunction is present, except in very advanced degrees where no significant benefit is obtained.

Iron deficiency and cardiovascular disease

Iron deficiency (ID) is common in patients with cardiovascular disease. Up to 60% of patients with coronary artery disease, and an even higher proportion of those with heart failure (HF) or pulmonary hypertension have ID; the evidence for cerebrovascular disease, aortic stenosis and atrial fibrillation is less robust. The prevalence of ID increases with the severity of cardiac and renal dysfunction and is probably more common amongst women. Insufficient dietary iron, reduced iron absorption due to increases in hepcidin secondary to the low-grade inflammation associated with atherosclerosis and congestion or reduced gastric acidity, and increased blood loss due to anti-thrombotic therapy or gastro-intestinal or renal disease may all cause ID. For older people in the general population and patients with HF with reduced ejection fraction (HFrEF), both anaemia and ID are associated with a poor prognosis; each may confer independent risk. There is growing evidence that ID is an important therapeutic target for patients with HFrEF, even if they do not have anaemia. Whether this is also true for other HF phenotypes or patients with cardiovascular disease in general is currently unknown. Randomized trials showed that intravenous ferric carboxymaltose improved symptoms, health-related quality of life and exercise capacity and reduced hospitalizations for worsening HF in patients with HFrEF and mildly reduced ejection fraction (<50%). Since ID is easy to treat and is effective for patients with HFrEF, such patients should be investigated for possible ID. This recommendation may extend to other populations in the light of evidence from future trials.

Crosstalk between Iron and Arteriosclerosis

Iron is an important element for life; however, intracellular labile iron overload can lead to the generation of reactive oxygen species and cellular damage. Although iron is mainly utilized for heme synthesis and is incorporated into hemoglobin, body iron status is often implicated in the pathogenesis of cardiovascular diseases. In a cell, iron is used for basic processes such as cell growth, maintenance, and repair. Thus, iron is considered to be involved in the pathogenesis of arteriosclerosis. In fact, clinical and experimental studies have shown an association between iron and arteriosclerosis. These data suggest the crosstalk between iron and arteriosclerosis. However, iron metabolism in arteriosclerosis is often complicated, and the systemic and cellular mechanisms of iron homeostasis in arteriosclerosis remain completely unsolved. Thus, in this review, we aimed to examine the role of iron in arteriosclerosis.

Iron Deficiency Impacts Diastolic Function, Aerobic Exercise Capacity, and Patient Phenotyping in Heart Failure With Preserved Ejection Fraction: A Subanalysis of the OptimEx-Clin Study

Aims

Iron deficiency (ID) is linked to reduced aerobic exercise capacity and poor prognosis in patients with heart failure (HF) with reduced ejection fraction (HFrEF); however, data for HF with preserved ejection fraction (HFpEF) is scarce. We assessed the relationship between iron status and diastolic dysfunction as well as aerobic exercise capacity in HFpEF, and the contribution of iron status to patient phenotyping.

Methods and Results

Among 180 patients with HFpEF (66% women; median age, 71 years) recruited for the Optimizing Exercise Training in Prevention and Treatment of Diastolic HF (OptimEx-Clin) trial, baseline iron status, including iron, ferritin, and transferrin saturation, was analyzed (n = 169) in addition to exercise capacity (peak oxygen uptake [peak V̇O₂]) and diastolic function (E/e′). ID was present in 60% of patients and was more common in women. In multivariable linear regression models, we found that diastolic function and peak V̇O₂ were independently related to iron parameters; however, these relationships were present only in patients with HFpEF and ID [E/e′ and iron: β−0.19 (95% confidence interval −0.32, −0.07), p = 0.003; E/e′ and transferrin saturation: β−0.16 (−0.28, −0.04), p = 0.011; peak V̇O₂ and iron: β 3.76 (1.08, 6.44), p = 0.007; peak V̇O₂ and transferrin saturation: β 3.58 (0.99, 6.16), p = 0.007]. Applying machine learning, patients were classified into three phenogroups. One phenogroup was predominantly characterized by the female sex and few HFpEF risk factors but a high prevalence of ID (86%, p < 0.001 vs. other phenogroups). When excluding ID from the phenotyping analysis, results were negatively influenced.

Conclusion

Iron parameters are independently associated with impaired diastolic function and low aerobic capacity in patients with HFpEF and ID. Patient phenotyping in HFpEF is influenced by including ID.

Clinical Trial Registration

www.ClinicalTrials.gov, identifier NCT02078947.

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.

Iron Overload, Oxidative Stress, and Ferroptosis in the Failing Heart and Liver

Iron accumulation is a key mediator of several cytotoxic mechanisms leading to the impairment of redox homeostasis and cellular death. Iron overload is often associated with haematological diseases which require regular blood transfusion/phlebotomy, and it represents a common complication in thalassaemic patients. Major damages predominantly occur in the liver and the heart, leading to a specific form of cell death recently named ferroptosis. Different from apoptosis, necrosis, and autophagy, ferroptosis is strictly dependent on iron and reactive oxygen species, with a dysregulation of mitochondrial structure/function. Susceptibility to ferroptosis is dependent on intracellular antioxidant capacity and varies according to the different cell types. Chemotherapy-induced cardiotoxicity has been proven to be mediated predominantly by iron accumulation and ferroptosis, whereas there is evidence about the role of ferritin in protecting cardiomyocytes from ferroptosis and consequent heart failure. Another paradigmatic organ for transfusion-associated complication due to iron overload is the liver, in which the role of ferroptosis is yet to be elucidated. Some studies report a role of ferroptosis in the initiation of hepatic inflammation processes while others provide evidence about an involvement in several pathologies including immune-related hepatitis and acute liver failure. In this manuscript, we aim to review the literature to address putative common features between the response to ferroptosis in the heart and liver. A better comprehension of (dys)similarities is pivotal for the development of future therapeutic strategies that can be designed to specifically target this type of cell death in an attempt to minimize iron-overload effects in specific organs.

Reduced lifespan of erythrocytes in Dahl/Salt sensitive rats is the cause of the renal proximal tubule damage

We studied the mechanisms of anemia and the influence of anemia on renal pathology in Dahl/Salt Sensitive (Dahl/SS) rat, a model of cardio-renal-anemia syndrome. Erythrocyte lifespan was shortened and associated with decreased hemoglobin level in the Dahl/SS rats given high-salt diet. Serum haptoglobin decreased, reticulocytes increased, and erythropoiesis in the bone marrow and extramedullary hematopoiesis in the spleen was markedly stimulated by increased serum erythropoietin in them. As a mechanism of hemolysis, we investigated the incidence of eryptosis, suicidal death of erythrocytes. Eryptosis was increased, and red blood cell-derived microparticles, small particle which are generated in hemolytic disease, were also increased in Dahl/SS rats fed with high-salt diet. Deposition of hemosiderin and mitochondrial morphologic abnormality, a sign of ferroptosis, in proximal renal tubules was associated with intravascular hemolysis. Treatment with deferasirox, an oral iron chelator, reduced the renal proximal tubular injury and the glomerular sclerosis in Dahl/SS rats fed with high-salt diet. In conclusion, reduced half-life of erythrocytes induced by hemolysis is the major cause of anemia in Dahl/SS rat. Iron accumulation induced by hemolysis causes renal proximal tubule injury and accelerates renal damage in this model.

Iron and cardiovascular diseases

Iron is a necessary element for life; however, excess iron leads to oxidative stress by the Fenton reaction. Iron deficiency is prevalent in patients with heart failure, while iron overload is associated in the pathogenesis of atherosclerosis. These findings suggest the "iron paradox" in cardiovascular diseases. Iron metabolism in cardiovascular diseases is complex, and the mechanisms regulating systemic and cellular iron metabolism in cardiovascular diseases remain completely unknown. In this review, we focus on the role of iron in cardiovascular diseases.

Keeping heart homeostasis in check through the balance of iron metabolism

Highly active cardiomyocytes need iron for their metabolic activity. In physiological conditions, iron turnover is a delicate process which is dependent on global iron supply and local autonomous regulatory mechanisms. Though less is known about the autonomous regulatory mechanisms, data suggest that these mechanisms can preserve cellular iron turnover even in the presence of systemic iron disturbance. Therefore, activity of local iron protein machinery and its relationship with global iron metabolism is important to understand cardiac iron metabolism in physiological conditions and in cardiac disease. Our knowledge in this respect has helped in designing therapeutic strategies for different cardiac diseases. This review is a synthesis of our current knowledge concerning the regulation of cardiac iron metabolism. In addition, different models of cardiac iron dysmetabolism will be discussed through the examples of heart failure (cardiomyocyte iron deficiency), myocardial infarction (acute changes in cardiac iron turnover), doxorubicin-induced cardiotoxicity (cardiomyocyte iron overload in mitochondria), thalassaemia (cardiomyocyte cytosolic and mitochondrial iron overload) and Friedreich ataxia (asymmetric cytosolic/mitochondrial cardiac iron dysmetabolism). Finally, future perspectives will be discussed in order to resolve actual gaps in knowledge, which should be helpful in finding new treatment possibilities in different cardiac diseases.

Impact of iron deficiency on long-term clinical outcomes of hospitalized patients with heart failure

BACKGROUND

Iron deficiency (ID) is commonly observed in chronic heart failure (HF) patients and is associated with worse clinical outcomes. While ID is frequent finding in hospitalized heart failure (HHF), its impact on long-term outcome in HHF patients remains unclear.

METHODS

We evaluated iron status at discharge in 578 HHF patients. Absolute ID was defined as serum ferritin <100 μg/L, and functional ID (FID) was defined as serum ferritin of 100-299 μg/L with transferrin saturation <20%. The primary outcome of interest was the composite of all-cause mortality and HF admission at one year.

RESULTS

Among the study population, 185 had absolute ID, 88 had FID and 305 had no evidence of ID. At one-year post-discharge, 64 patients had died and 112 had been readmitted with HF. Patients with absolute ID had more adverse events than those with FID or no ID (p = 0.021). In multivariate Cox regression analyses, absolute ID was significantly associated with increased risk of adverse events at one year (HR 1.50, 95% CI 1.02-2.21, p = 0.040) compared with the remaining patients. Sensitivity analysis revealed that its prognostic effect did not differ across anemic status, or between HF with reduced and preserved ejection fraction (p for interaction = 0.17, 0.68, respectively).

CONCLUSION

Absolute ID, but not FID, at discharge was associated with increased risk of one-year mortality or HF admission in patients with HHF. Further studies are required to evaluate the role of repleting iron stores and its impact on clinical outcomes in patients with HHF.

Influence of dietary iron intake restriction on the development of hypertension in weanling prehypertensive rats

Hypertension is a major public health problem leading to death. To reduce the morbidity and mortality in patients with hypertension, it is crucial to develop a novel strategy for prevention of hypertension. We have currently reported an attempt at dietary iron intake restriction as non-pharmacological treatment of hypertension in patients with hypertension. However, it remains fully unknown whether dietary iron restriction prevents the development of hypertension. We investigated the influence of dietary iron restriction on the development of hypertension in weanling pre-hypertensive model rats. 3-week-old male stroke-prone spontaneously hypertensive rats (SHR-SP) were randomly divided into two groups and were given an ad libitum normal diet or an iron-restricted diet for 12 weeks. Blood pressure was progressively increased in SHR-SP according to growth, while dietary iron restriction attenuated the development of hypertension. Proteinuria was also increased in SHR-SP according to growth, whereas dietary iron restriction suppressed the increment of proteinuria. SHR-SP exhibited glomerulosclerosis and exacerbated renal interstitial fibrosis at 15 weeks old, indicating that SHR-SP developed hypertensive nephropathy in the adult stage; however, these changes were attenuated by dietary iron restriction. Gelatin zymography showed dietary iron restriction decreased both renal MMP-2 and MMP-9 activities in SHR-SP at 15 weeks old. Of interest, dietary iron restriction suppressed renal TGFβ-RI expression and Smad2 phosphorylation in SHR-SP. Furthermore, dietary iron restriction decreased renal fibrosis, renal MMP-2 and MMP-9 activities, renal TGFβ-RI expression, and Smad2 phosphorylation in rats with unilateral ureteral obstruction. Dietary iron restriction prevented the development of hypertension in weanling pre-hypertensive rats.

Altered expression of intestinal duodenal cytochrome b and divalent metal transporter 1 might be associated with cardio-renal anemia syndrome

The interaction among heart failure (HF), chronic kidney disease (CKD), and anemia is called cardio-renal anemia syndrome. The mechanism of anemia in cardio-renal anemia syndrome is complex and remains completely unknown. We have previously reported that impaired intestinal iron transporters may contribute to the mechanism of anemia in HF using in vivo HF model rats. In this study, we assessed intestinal iron transporters in CKD model rats to investigate the association of intestinal iron transporters in the mechanism of cardio-renal anemia syndrome. CKD was induced by 5/6 nephrectomy in Sprague-Dawley rats. Sham-operated rats served as a control. After 24-week surgery, CKD rats exhibited normocytic normochromic anemia and normal serum erythropoietin levels despite of anemia. Serum iron levels were decreased in CKD rats compared with the controls. Of interest, intestinal expression of critical iron importers, such as duodenal cytochrome b (Dcyt-b) and divalent metal transporter 1 (DMT-1), was decreased in CKD rats compared with the controls. On the other hand, intestinal expression of ferroportin, an intestinal iron exporter, was not different in the control and CKD groups. Moreover, hepatic expression of hepcidin, a regulator of iron homeostasis, did not differ between the control and CKD groups. These results suggest that impaired intestinal expression of Dcyt-b and DMT-1 might be associated with the reduction of an iron uptake in CKD. Taken together, impaired these intestinal iron transporters may become a novel therapeutic target for cardio-renal anemia syndrome.

Is cardiac and hepatic iron status assessed by MRI T2* associated with left ventricular function in patients with idiopathic cardiomyopathy?

Excess accumulation of iron in the heart is known to aggravate cardiac function in some cases of genetic and acquired iron overload. We investigated the possible association between cardiac function and iron content in the heart and liver, estimated non-invasively by T2 star (T2*)-weighted magnetic resonance (MR) imaging among patients with cardiomyopathy. MR images were acquired on a 3.0 T MR imaging system using an 8-channel phased-array cardiac coil. Average T2* values of the heart were estimated at regions of interest that were located on short axis mid-ventricular slices positioned at the cardiac septum. In total, 82 patients were enrolled: 48 patients with dilated cardiomyopathy (DCM), 16 patients with hypertrophic cardiomyopathy (HCM), and 18 patients without apparent cardiovascular abnormalities. Cardiac T2* values were lower in the DCM group (median 18.6 ms) than in the HCM (22.0 ms) and control (21.4 ms) groups, although hepatic T2* values did not differ significantly across the groups. Among the whole population, the highest cardiac T2* tertile (≥21.2 ms) was significantly negatively associated with a low left ventricular ejection fraction (LVEF) of <50 %, and this association retained statistical significance after adjustment for sex, age, renal function, hemoglobin and hepatic T2*. Among DCM patients, both hemoglobin and cardiac T2* were selected as parameters that were, respectively, negatively and positively, associated with LVEF (P < 0.05). DCM patients with lower cardiac T2*, and thus higher iron content, were found to have lower LVEF. The possibility that cardiac iron overload may have a role in reducing the systolic cardiac function in DCM patients who do not have systemic iron overload requires further investigation in the future.

Beneficial effects of long-term intravenous iron therapy with ferric carboxymaltose in patients with symptomatic heart failure and iron deficiency†

Aim

The aim of this study was to evaluate the benefits and safety of long-term i.v. iron therapy in iron-deficient patients with heart failure (HF).

Methods and results

CONFIRM-HF was a multi-centre, double-blind, placebo-controlled trial that enrolled 304 ambulatory symptomatic HF patients with left ventricular ejection fraction ≤45%, elevated natriuretic peptides, and iron deficiency (ferritin <100 ng/mL or 100–300 ng/mL if transferrin saturation <20%). Patients were randomized 1 : 1 to treatment with i.v. iron, as ferric carboxymaltose (FCM, n = 152) or placebo (saline, n = 152) for 52 weeks. The primary end-point was the change in 6-min-walk-test (6MWT) distance from baseline to Week 24. Secondary end-points included changes in New York Heart Association (NYHA) class, Patient Global Assessment (PGA), 6MWT distance, health-related quality of life (QoL), Fatigue Score at Weeks 6, 12, 24, 36, and 52 and the effect of FCM on the rate of hospitalization for worsening HF. Treatment with FCM significantly prolonged 6MWT distance at Week 24 (difference FCM vs. placebo: 33 ± 11 m, P = 0.002). The treatment effect of FCM was consistent in all subgroups and was sustained to Week 52 (difference FCM vs. placebo: 36 ± 11 m, P < 0.001). Throughout the study, an improvement in NYHA class, PGA, QoL, and Fatigue Score in patients treated with FCM was detected with statistical significance observed from Week 24 onwards. Treatment with FCM was associated with a significant reduction in the risk of hospitalizations for worsening HF [hazard ratio (95% confidence interval): 0.39 (0.19–0.82), P = 0.009]. The number of deaths (FCM: 12, placebo: 14 deaths) and the incidence of adverse events were comparable between both groups.

Conclusion

Treatment of symptomatic, iron-deficient HF patients with FCM over a 1-year period resulted in sustainable improvement in functional capacity, symptoms, and QoL and may be associated with risk reduction of hospitalization for worsening HF (ClinicalTrials.gov number NCT01453608).

High prevalence of iron deficiency in patients with acute decompensated heart failure

AIMS

Limited data are available on iron parameters in patients hospitalized for decompensation of chronic heart failure.

METHODS AND RESULTS

Iron parameters of patients hospitalized for decompensation of chronic heart failure were prospectively assessed during the 72 h after hospital admission. Iron deficiency was defined according to the 2012 European Society of Cardiology Guidelines. Overall, 411 men (75 ± 12  years; 75% NYHA functional classes III/IV) and 421 women (81 ± 11 years; 71% NYHA classes III/IV) were evaluated. The prevalence of iron deficiency was 69% in men and 75% in women (including 41% and 49% with absolute iron deficiency, respectively). The prevalence of anaemia in men (<13 g/dL) was 68% and in women (<12 g/dL) it was 52%. Among non-anaemic patients, the prevalence of iron deficiency was 57% in men and 79% in women. Only 9% of patients received iron supplementation at the time of admission (oral, 9%; intravenous, 0.2%). Multivariate analysis showed that anaemia and antiplatelet treatment in men, and diabetes and low C-reactive protein in women, were independently associated with iron deficiency.

CONCLUSIONS

Iron deficiency is very common in patients admitted for acute decompensated heart failure, even among non-anaemic patients. Given the benefit of iron therapy in chronic heart failure, our results emphasize the need to assess iron status not only in chronic heart failure patients, but even more so in those admitted for worsening heart failure, regardless of gender, heart failure severity, or haemoglobin level. Initiating iron therapy in hospitalized heart failure patients needs to be investigated.

Nonregenerative anemia: mechanisms of decreased or ineffective erythropoiesis

In veterinary medicine, anemia without an appropriate compensatory hematopoietic response is termed nonregenerative. Nonregenerative anemia is a common clinical entity, occurring as a result of diminished or ineffective erythropoiesis in association with many types of pathology. This article reviews nonregenerative anemia in domestic animals, emphasizing mechanisms of disease, and also covers other conditions associated with nonregenerative anemia in people. Many aspects of nonregenerative anemia in animals are worthy of further investigation, from molecular mechanisms of disease to epidemiologic impacts.

Iron deficiency anemia in heart failure

Anemia and iron deficiency are quite prevalent in patients with heart failure (HF) and may overlap. Both anemia and iron deficiency are associated with worse symptoms and adverse clinical outcomes. In the past few years, there has been an enormous interest in the subject of iron deficiency and its management in patients with HF. In this review, the etiology and relevance of iron deficiency, iron metabolism in the setting of HF, studies on iron supplementation in patients with HF and potential cardiovascular effects of subclinical iron overload are discussed.

Cardiorenal syndrome: pathophysiology and potential targets for clinical management

Combined dysfunction of the heart and the kidneys, which can be associated with haemodynamic impairment, is classically referred to as cardiorenal syndrome (CRS). Cardiac pump failure with resulting volume retention by the kidneys, once thought to be the major pathophysiologic mechanism of CRS, is now considered to be only a part of a much more complicated phenomenon. Multiple body systems may contribute to the development of this pathologic constellation in an interconnected network of events. These events include heart failure (systolic or diastolic), atherosclerosis and endothelial cell dysfunction, uraemia and kidney failure, neurohormonal dysregulation, anaemia and iron disorders, mineral metabolic derangements including fibroblast growth factor 23, phosphorus and vitamin D disorders, and inflammatory pathways that may lead to malnutrition-inflammation-cachexia complex and protein-energy wasting. Hence, a pathophysiologically and clinically relevant classification of CRS based on the above components would be prudent. With the existing medical knowledge, it is almost impossible to identify where the process has started in any given patient. Rather, the events involved are closely interrelated, so that once the process starts at a particular point, other pathways of the network are potentially activated. Current therapies for CRS as well as ongoing studies are mostly focused on haemodynamic adjustments. The timely targeting of different components of this complex network, which may eventually lead to haemodynamic and vascular compromise and cause refractoriness to conventional treatments, seems necessary. Future studies should focus on interventions targeting these components.

Iron deficiency and heart failure: diagnostic dilemmas and therapeutic perspectives

Iron is a micronutrient essential for cellular energy and metabolism, necessary for maintaining body homoeostasis. Iron deficiency is an important co-morbidity in patients with heart failure (HF). A major factor in the pathogenesis of anaemia, it is also a separate condition with serious clinical consequences (e.g. impaired exercise capacity) and poor prognosis in HF patients. Experimental evidence suggests that iron therapy in iron-deficient animals may activate molecular pathways that can be cardio-protective. Clinical studies have demonstrated favourable effects of i.v. iron on the functional status, quality of life, and exercise capacity in HF patients. It is hypothesized that i.v. iron supplementation may become a novel therapy in HF patients with iron deficiency.

Anemia and iron deficiency in heart failure: mechanisms and therapeutic approaches

Anemia and iron deficiency are common in patients with heart failure (HF), and are associated with worse symptoms and adverse outcomes in this population. Although the two can occur together, anemia in HF is often not caused by iron deficiency, and iron deficiency can be present without causing anemia. Erythropoiesis-stimulating agents have been investigated extensively in the past few years and might be of benefit in patients with HF and anemia. However, concerns have arisen regarding the safety of erythropoiesis-stimulating agents in patients with chronic kidney disease and so the results of a large mortality trial are eagerly awaited to provide information on safety in patients with HF. Iron supplementation or replacement is a much older treatment option for patients with HF and anemia, but questions about the safety of intravenous iron, and absorption problems with oral formulations have prevented its widespread use to date. In the past few years, however, new data on the importance of iron deficiency in HF have become available, and a number of studies with intravenous iron have shown promising results. Therefore, this treatment approach is likely to become an attractive option for patients with HF and iron deficiency, both with and without anemia.