Iron overload cardiomyopathy: better understanding of an increasing disorder

Knockdown of LncRNA Lcn2-204 alleviates sepsis-induced myocardial injury by regulation of iron overload and ferroptosis

Ferroptosis is an iron-dependent programmed cell death form resulting from lipid peroxidation damage, it plays a key role in organ damage and tumor development from various causes. Sepsis leads to severe host response after infection with high mortality. The long non-coding RNAs (LncRNAs) are involved in different pathophysiological mechanisms of multiple diseases. Here, we used cecal ligation and puncture (CLP) operation to mimic sepsis induced myocardial injury (SIMI) in mouse model, and LncRNAs and mRNAs were profiled by Arraystar mouse LncRNA Array V3.0. Based on the microarray results, 552 LncRNAs and 520 mRNAs were differentially expressed in the sham and CLP groups, among them, LncRNA Lcn2-204 was the highest differentially expressed up-regulated LncRNA. Iron metabolism disorder was involved in SIMI by bioinformatics analysis, meanwhile, myocardial iron content and lipocalin-2 (Lcn2) protein expressions were increased. The CNC network comprised 137 positive interactions and 138 negative interactions. Bioinformatics analysis showed several iron-related terms were enriched and six genes (Scara5, Tfrc, Lcn2, Cp, Clic5, Ank1) were closely associated with iron metabolism. Then, we constructed knockdown LncRNA Lcn2-204 targeting myocardium and found that it ameliorated cardiac injury in mouse sepsis model through modulating iron overload and ferroptosis. In addition, we found that LncRNA Lcn2-204 was involved in the regulation of Lcn2 expression in septic myocardial injury. Based on these findings, we conclude that iron overload and ferroptosis are the key mechanisms leading to myocardial injury in sepsis, knockdown of LncRNA Lcn2-204 plays the cardioprotective effect through inhibition of iron overload, ferroptosis and Lcn2 expression. It may provide a novel therapeutic approach to ameliorate sepsis-induced myocardial injury.

Trace Element Concentrations in Autopsied Heart Tissues from Patients with Secondary Cardiomyopathy

Cardiomyopathies (CMP) represent a significant health problem as they have a poor long-term prognosis and often require transplantation. Heavy metals are known to have cardiotoxic effects and some of them, such as cadmium (Cd), are found to be elevated in the urine and blood of individuals with heart diseases; nevertheless, direct measurement of metals (e.g. zinc (Zn) which is necessary for normal heart function), in the myocardium of individuals with CMP has not been performed. Here, we aimed to analyze the levels of a group of metals in the myocardium of the left ventricle in individuals with CMP. At the Institute of Pathology, we collected 52 samples of left ventricle post-mortem, out of which 19 subjects had been diagnosed with CMP (mean age: 72 y ± 10), and 33 subjects had not suffered from any heart disease (mean age: 67 y ± 15). We found out that individuals with CMP had a significantly higher concentrations of lead, nickel, manganese and copper than non-CMP subjects (p = 0.002, p < 0.001, p = 0.011, and p = 0.002). Interestingly, zinc was significantly lower in CMP subjects than in n-CMP individuals (p = 0.017). Our results indicated the involvement of an increased lead, nickel, copper and manganese heart load in individuals with CMP coupled with lower concentrations of zinc.

Cardiac effects of deferasirox in transfusion-dependent patients with myelodysplastic syndromes: TELESTO study

Iron overload from repeated transfusions has a negative impact on cardiac function, and iron chelation therapy may help prevent cardiac dysfunction in transfusion-dependent patients with myelodysplastic syndromes (MDS). TELESTO (NCT00940602) was a prospective, placebo-controlled, randomised study to evaluate the iron chelator deferasirox in patients with low- or intermediate-1-risk MDS and iron overload. Echocardiographic parameters were collected at screening and during treatment. Patients receiving deferasirox experienced a significant decrease in the composite risk of hospitalisation for congestive heart failure (CHF) or worsening of cardiac function (HR = 0.23; 95% CI: 0.05, 0.99; nominal p = 0.0322) versus placebo. No significant differences between the arms were found in left ventricular ejection fraction, ventricular diameter and mass or pulmonary artery pressure. The absolute number of events was low, but the enrolled patients were younger than average for patients with MDS, with no serious cardiac comorbidities and a modest cardiovascular risk profile. These results support the effectiveness of deferasirox in preventing cardiac damage caused by iron overload in this patient population. Identification of patients developing CHF is challenging due to the lack of distinctive echocardiographic features. The treatment of iron overload may be important to prevent cardiac dysfunction in these patients, even those with moderate CHF risk.

The Role of Magnetic Resonance Imaging in Cardiomyopathies in the Light of New Guidelines: A Focus on Tissue Mapping

Cardiomyopathies (CMPs) are a group of myocardial disorders that are characterized by structural and functional abnormalities of the heart muscle. These abnormalities occur in the absence of coronary artery disease (CAD), hypertension, valvular disease, and congenital heart disease. CMPs are an increasingly important topic in the field of cardiovascular diseases due to the complexity of their diagnosis and management. In 2023, the ESC guidelines on cardiomyopathies were first published, marking significant progress in the field. The growth of techniques such as cardiac magnetic resonance imaging (CMR) and genetics has been fueled by the development of multimodal imaging approaches. For the diagnosis of CMPs, a multimodal imaging approach, including CMR, is recommended. CMR has become the standard for non-invasive analysis of cardiac morphology and myocardial function. This document provides an overview of the role of CMR in CMPs, with a focus on tissue mapping. CMR enables the characterization of myocardial tissues and the assessment of cardiac functions. CMR sequences and techniques, such as late gadolinium enhancement (LGE) and parametric mapping, provide detailed information on tissue composition, fibrosis, edema, and myocardial perfusion. These techniques offer valuable insights for early diagnosis, prognostic evaluation, and therapeutic guidance of CMPs. The use of quantitative CMR markers enables personalized treatment plans, improving overall patient outcomes. This review aims to serve as a guide for the use of these new tools in clinical practice.

Research advances on molecular mechanism and natural product therapy of iron metabolism in heart failure

The progression of heart failure (HF) is complex and involves multiple regulatory pathways. Iron ions play a crucial supportive role as a cofactor for important proteins such as hemoglobin, myoglobin, oxidative respiratory chain, and DNA synthetase, in the myocardial energy metabolism process. In recent years, numerous studies have shown that HF is associated with iron dysmetabolism, and deficiencies in iron and overload of iron can both lead to the development of various myocarditis diseases, which ultimately progress to HF. Iron toxicity and iron metabolism may be key targets for the diagnosis, treatment, and prevention of HF. Some iron chelators (such as desferrioxamine), antioxidants (such as ascorbate), Fer-1, and molecules that regulate iron levels (such as lactoferrin) have been shown to be effective in treating HF and protecting the myocardium in multiple studies. Additionally, certain natural compounds can play a significant role by mediating the imbalance of iron-related signaling pathways and expression levels. Therefore, this review not only summarizes the basic processes of iron metabolism in the body and the mechanisms by which they play a role in HF, with the aim of providing new clues and considerations for the treatment of HF, but also summarizes recent studies on natural chemical components that involve ferroptosis and its role in HF pathology, as well as the mechanisms by which naturally occurring products regulate ferroptosis in HF, with the aim of providing reference information for the development of new ferroptosis inhibitors and lead compounds for the treatment of HF in the future.

Iron status determined changes in health measures induced by nordic walking with time-restricted eating in older adults- a randomised trial

BACKGROUND AND AIMS

This study evaluated whether stored iron determines the adaptive response induced by Nordic walking (NW) training combined with 10 hours' time-restricted eating (TRE) in older adults.

TRIAL DESIGN AND METHODS

Twenty-four participants underwent 12-week NW training supported by 10 h of TRE. The group was divided due to baseline ferritin concentration low < 75 ng/ml (LF) and high level ≥ 75 ng/ml (HF). Body composition, physical fitness and blood collection were assessed at baseline and post-intervention.

RESULTS

NW + TRE induced a statistically significant decrease in ferritin levels in all participants (p = 0.01). Additionally, statistically significant intergroup differences in the LF vs. HF in the reduction of serum ferritin levels (p = 0.04) were observed. The procedure NW + TRE diminished HbA1c levels (p < 0.01) and glucose in all participants (p = 0.05). The range of HbA1c drop was more pronounced among those participants who experienced a greater decrease in the stored iron (p = 0.04, [Formula: see text]=0.17, F=4.59). Greater changes in body weight and percent of body fat were recorded in the HF group (for both p<0.01).

CONCLUSION

Body iron stores determine the effects of a 12-week NW + TRE intervention on serum ferritin. The changes in HbA1c are more pronounced in subjects with a higher decrease in serum ferritin.

TRIAL REGISTRATION

All experimental protocols were approved by the Bioethical Committee of the Regional Medical Society in Gdansk, Poland (NKBBN/330/2021) according to the Declaration of Helsinki. We confirm that all methods were carried out in accordance with relevant guidelines and regulations. The trial was registered as a clinical trial (NCT05229835, date of first registration: 14/01/2022, direct link: https://classic.

CLINICALTRIALS

gov/ct2/show/NCT05229835 ). Informed consent was obtained from all subjects.

Hereditary hemochromatosis with homozygous C282Y HFE mutation: possible clinical model to assess effects of elevated reactive oxygen species on the development of cardiovascular disease

Hereditary hemochromatosis with the homozygous C282Y HFE mutation (HH-282H) is a genetic condition which causes iron overload (IO) and elevated reactive oxygen species (ROS) secondary to the IO. Interestingly, even after successful iron removal therapy, HH-282H subjects demonstrate chronically elevated ROS. Raised ROS are also associated with the development of multiple cardiovascular diseases and HH-282H subjects may be at risk to develop these complications. In this narrative review, we consider HH-282H subjects as a clinical model for assessing the contribution of elevated ROS to the development of cardiovascular diseases in subjects with fewer confounding clinical risk factors as compared to other disease conditions with high ROS. We identify HH-282H subjects as a potentially unique clinical model to assess the impact of chronically elevated ROS on the development of cardiovascular disease and to serve as a clinical model to detect effective interventions for anti-ROS therapy.

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

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

Investigating gastrointestinal disorders in pregnancy

This article reviews anatomical and physiological changes and alterations in reference intervals for laboratory tests in healthy pregnancy, pertinent to investigation of the gastrointestinal system. The safety of procedures and radiological investigations relevant to the investigation of gastrointestinal disorders in pregnancy are also reviewed.

Dysregulated iron homeostasis in dystrophin-deficient cardiomyocytes: correction by gene editing and pharmacological treatment

AIMS

Duchenne muscular dystrophy (DMD)-associated cardiomyopathy is a serious life-threatening complication, the mechanisms of which have not been fully established, and therefore no effective treatment is currently available. The purpose of the study was to identify new molecular signatures of the cardiomyopathy development in DMD.

METHODS AND RESULTS

For modelling of DMD-associated cardiomyopathy, we prepared three pairs of isogenic control and dystrophin-deficient human induced pluripotent stem cell (hiPSC) lines. Two isogenic hiPSC lines were obtained by CRISPR/Cas9-mediated deletion of DMD exon 50 in unaffected cells generated from healthy donor and then differentiated into cardiomyocytes (hiPSC-CM). The latter were subjected to global transcriptomic and proteomic analyses followed by more in-depth investigation of selected pathway and pharmacological modulation of observed defects. Proteomic analysis indicated a decrease in the level of mitoNEET protein in dystrophin-deficient hiPSC-CM, suggesting alteration in iron metabolism. Further experiments demonstrated increased labile iron pool both in the cytoplasm and mitochondria, a decrease in ferroportin level and an increase in both ferritin and transferrin receptor in DMD hiPSC-CM. Importantly, CRISPR/Cas9-mediated correction of the mutation in the patient-derived hiPSC reversed the observed changes in iron metabolism and restored normal iron levels in cardiomyocytes. Moreover, treatment of DMD hiPSC-CM with deferoxamine (DFO, iron chelator) or pioglitazone (mitoNEET stabilizing compound) decreased the level of reactive oxygen species in DMD hiPSC-CM.

CONCLUSION

To our knowledge, this study demonstrated for the first time impaired iron metabolism in human DMD cardiomyocytes, and potential reversal of this effect by correction of DMD mutation or pharmacological treatment. This implies that iron overload-regulating compounds may serve as novel therapeutic agents in DMD-associated cardiomyopathy.

High Dietary Intake of Iron Might Be Harmful to Atrial Fibrillation and Modified by Genetic Diversity: A Prospective Cohort Study

Some studies suggest an association between iron overload and cardiovascular diseases (CVDs). However, the relationship between dietary iron intake and atrial fibrillation (AF) remains uncertain, as does the role of genetic loci on this association. The study involved 179,565 participants from UK Biobank, tracking incident atrial fibrillation (AF) cases. Iron intake was categorized into low, moderate, and high groups based on dietary surveys conducted from 2009 to 2012. The Cox regression model was used to estimate the risk of AF in relation to iron intake, assessing the hazard ratio (HR) and 95% confidence interval (95% CI). It also examined the impact of 165 AF-related and 20 iron-related genetic variants on this association. Pathway enrichment analyses were performed using Metascape and FUMA. During a median follow-up period of 11.6 years, 6693 (3.97%) incident AF cases were recorded. A total of 35,874 (20.0%) participants had high iron intake. High iron intake was associated with increased risk of AF [HR: 1.13 (95% CI: 1.05, 1.22)] in a fully adjusted model. Importantly, there were 83 SNPs (11 iron-related SNPs) that could enhance the observed associations. These genes are mainly involved in cardiac development and cell signal transduction pathways. High dietary iron intake increases the risk of atrial fibrillation, especially when iron intake exceeds 16.95 mg. The association was particularly significant among the 83 SNPs associated with AF and iron, the individuals with these risk genes. Gene enrichment analysis revealed that these genes are significantly involved in cardiac development and cell signal transduction processes.

Heterogeneous ferroptosis susceptibility of macrophages caused by focal iron overload exacerbates rheumatoid arthritis

Focal iron overload is frequently observed in patients with rheumatoid arthritis (RA), yet its functional significance remains elusive. Herein, we report that iron deposition in lesion aggravates arthritis by inducing macrophage ferroptosis. We show that excessive iron in synovial fluid positively correlates with RA disease severity as does lipid hyperoxidation of focal monocyte/macrophages. Further study reveals high susceptibility to iron induced ferroptosis of the anti-inflammatory macrophages M2, while pro-inflammatory M1 are less affected. Distinct glutathione peroxidase 4 (GPX4) degradation depending on p62/SQSTM1 in the two cell types make great contribution mechanically. Of note, ferroptosis inhibitor liproxstatin-1 (LPX-1) can alleviate the progression of K/BxN serum-transfer induced arthritis (STIA) mice accompanied with increasing M2 macrophages proportion. We thus propose that the heterogeneous ferroptosis susceptibility of macrophage subtypes as well as consequent inflammation and immune disorders are potential biomarkers and therapeutic targets in RA.

Severe iron overload cardiomyopathy manifested as acute myopericarditis: A case report

Iron overload cardiomyopathy (IOC) is a condition in which iron deposition in the heart causes cardiac dysfunction. We described a 21-year-old woman who presented with acute chest pain, dyspnea, and fever. The patient had a history of transfusion-dependent thalassemia (TDT) and secondary hemochromatosis with the latest serum ferritin ranging from 8000 to 15,000. Physical examinations revealed signs of anemia and heart failure. Electrocardiography showed diffuse ST-segment elevation with reciprocal ST-segment depression in aVR and complete atrioventricular block. Cardiac markers were markedly elevated. Echocardiography demonstrated the dilated size, impaired systolic function, global wall hypokinesia, restrictive filling pattern of the left ventricle, and a small amount of pericardial effusion. Coronary angiography showed normal coronary arteries. A cardiac magnetic resonance imaging showed multifocal early and late gadolinium enhancement involving mid-wall and subepicardial areas of biventricular myocardium suggestive of diffuse myocardial injury from an inflammatory process. She was provisionally diagnosed with acute myopericarditis. Ibuprofen and loop diuretic were prescribed; however, cardiogenic shock occurred. Thus, an endomyocardial biopsy was done and revealed diffuse myocardial hemosiderin deposition without evidence of inflammatory cell infiltration. Severe IOC mimicking acute myopericarditis was considered based on an endomyocardial biopsy result. An intravenous iron chelating agent was immediately administered. Unfortunately, cardiogenic shock was refractory resulting in death. This case demonstrated a rare manifestation of IOC, which can masquerade as acute myopericarditis, and emphasized that IOC should be differentially diagnosed, particularly in patients with TDT and hemochromatosis.

Clinical utility of circulating TWEAK and CD163 as biomarkers of iron-induced cardiac decompensation in transfusion dependent thalassemia major

BACKGROUND AND AIM

Tumor necrosis factor-like weak inducer of apoptosis (TWEAK) affects most of the cells involved in cardiac fibrosis like inflammatory cells, cardiomyocytes and fibroblasts. CD163, the receptor of TWEAK on the surface of type 2 macrophages, is shed into plasma upon macrophages activation. This work aimed to evaluate serum TWEAK and its decoy receptor CD163 as probable biomarkers to monitor myocardial iron overload (MIO) in transfusion dependent thalassemia major (TDTM) patients and to predict iron-induced cardiac decompensation (IICD).

METHODS

A total of 140 TDTM patients were enrolled. Patients were categorized into two groups; group I (n = 70) diagnosed with IICD while group II (n = 70) had no evidence of IICD. sTWEAK and sCD163 were quantitated utilizing Enzyme-linked-immunosorbent- assay.

RESULTS

sTWEAK was evidently lower in group I than group II (medians, 412 and 1052 pg/mL respectively). sCD163 was higher in group I than group II (medians, 615.5 and 323.5 ng/mL respectively). sTWEAK positively correlated with cardiac MRI-T2 mapping and ventricular ejection fractions and negatively correlated with B-Natriuretic peptide and cardiac troponin. An inverse relationship between TWEAK and CD163 was documented throughout the study. sTWEAK, sCD163 and TWEAK/CD163 ratio proved to be significant predictors of IICD in TDTM patients. TWEAK/CD163 ratio < 1.04 discriminated IICD in TDTM patients with 100 % clinical sensitivity and specificity.

CONCLUSION

Circulating TWEAK and CD163 appears to be promising biomarkers for monitoring MIO and predicting IICD in TDTM patients.

Revealing the contribution of iron overload-brown adipocytes to iron overload cardiomyopathy: Insights from RNA-seq and exosomes coculture technology

Iron overload has been demonstrated to be associated with insulin resistance, iron overload cardiomyopathy (IOC). Brown adipose tissue (BAT) is emerging as a novel therapeutic target for the treatment of various diseases, not only because of its capacity for dissipating excess energy via non-shivering thermogenesis, but also because of its implication in physiological and pathophysiological processes. However, little attention has been devoted to the precise alterations and impacts of iron overload-BAT. We conducted RNA-Seq analysis on BAT samples obtained from mice subjected to a high iron diet (HID) or a normal chow diet (CON), respectively. The RNA-seq transcriptomic analysis revealed that 1,289 differentially expressed RNAs (DEGs) were identified, with a higher number of the downregulated genes (910 genes) compared to the upregulated genes (379 genes). The results of Gene Ontology (GO) and The Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis indicated that the downregulated DEGs were primarily involved in hypertrophic cardiomyopathy, dilated cardiomyopathy, which were defined as IOC under the iron overload condition. The association between iron overload-BAT with cardiomyopathy was further investigated using exosome coculture technology. Our results demonstrated that the exosomes derived from ferric citrate treated-mature HIB 1B brown adipocytes, could be internalized by HL-1 cardiomyocytes, and contributed to the dysfunction in these cells. The present study has revealed the alterations and impacts of iron overload-BAT, particularly on the onset of IOC via not only RNA-seq but also exosomes coculture technology. The outputs might shed light on the novel therapeutic strategies for the treatment of IOC.

Calcium channel blockers for preventing cardiomyopathy due to iron overload in people with transfusion-dependent beta thalassaemia

BACKGROUND

Beta-thalassaemia is an inherited blood disorder that reduces the production of haemoglobin. The most severe form requires recurrent blood transfusions, which can lead to iron overload. Cardiovascular dysfunction caused by iron overload is the leading cause of morbidity and mortality in people with transfusion-dependent beta-thalassaemia. Iron chelation therapy has reduced the severity of systemic iron overload, but removal of iron from the myocardium requires a very proactive preventive strategy. There is evidence that calcium channel blockers may reduce myocardial iron deposition. This is an update of a Cochrane Review first published in 2018.

OBJECTIVES

To assess the effects of calcium channel blockers plus standard iron chelation therapy, compared with standard iron chelation therapy (alone or with a placebo), on cardiomyopathy due to iron overload in people with transfusion-dependent beta thalassaemia.

SEARCH METHODS

We searched the Cochrane Haemoglobinopathies Trials Register, compiled from electronic database searches and handsearching of journals and conference abstract books, to 13 January 2022. We also searched ongoing trials databases and the reference lists of relevant articles and reviews.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) of calcium channel blockers combined with standard chelation therapy versus standard chelation therapy alone or combined with placebo in people with transfusion-dependent beta thalassaemia.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods. We used GRADE to assess certainty of evidence.

MAIN RESULTS

We included six RCTs (five parallel-group trials and one cross-over trial) with 253 participants; there were 126 participants in the amlodipine arms and 127 in the control arms. The certainty of the evidence was low for most outcomes at 12 months; the evidence for liver iron concentration was of moderate certainty, and the evidence for adverse events was of very low certainty. Amlodipine plus standard iron chelation compared with standard iron chelation (alone or with placebo) may have little or no effect on cardiac T2* values at 12 months (mean difference (MD) 1.30 ms, 95% confidence interval (CI) -0.53 to 3.14; 4 trials, 191 participants; low-certainty evidence) and left ventricular ejection fraction (LVEF) at 12 months (MD 0.81%, 95% CI -0.92% to 2.54%; 3 trials, 136 participants; low-certainty evidence). Amlodipine plus standard iron chelation compared with standard iron chelation (alone or with placebo) may reduce myocardial iron concentration (MIC) after 12 months (MD -0.27 mg/g, 95% CI -0.46 to -0.08; 3 trials, 138 participants; low-certainty evidence). The results of our analysis suggest that amlodipine has little or no effect on heart T2*, MIC, or LVEF after six months, but the evidence is very uncertain. Amlodipine plus standard iron chelation compared with standard iron chelation (alone or with placebo) may increase liver T2* values after 12 months (MD 1.48 ms, 95% CI 0.27 to 2.69; 3 trials, 127 participants; low-certainty evidence), but may have little or no effect on serum ferritin at 12 months (MD 0.07 μg/mL, 95% CI -0.20 to 0.35; 4 trials, 187 participants; low-certainty evidence), and probably has little or no effect on liver iron concentration (LIC) after 12 months (MD -0.86 mg/g, 95% CI -4.39 to 2.66; 2 trials, 123 participants; moderate-certainty evidence). The results of our analysis suggest that amlodipine has little or no effect on serum ferritin, liver T2* values, or LIC after six months, but the evidence is very uncertain. The included trials did not report any serious adverse events at six or 12 months of intervention. The studies did report mild adverse effects such as oedema, dizziness, mild cutaneous allergy, joint swelling, and mild gastrointestinal symptoms. Amlodipine may be associated with a higher risk of oedema (risk ratio (RR) 5.54, 95% CI 1.24 to 24.76; 4 trials, 167 participants; very low-certainty evidence). We found no difference between the groups in the occurrence of other adverse events, but the evidence was very uncertain. No trials reported mortality, cardiac function assessments other than echocardiographic estimation of LVEF, electrocardiographic abnormalities, quality of life, compliance with treatment, or cost of interventions.

AUTHORS' CONCLUSIONS

The available evidence suggests that calcium channel blockers may reduce MIC and may increase liver T2* values in people with transfusion-dependent beta thalassaemia. Longer-term multicentre RCTs are needed to assess the efficacy and safety of calcium channel blockers for myocardial iron overload, especially in younger children. Future trials should also investigate the role of baseline MIC in the response to calcium channel blockers, and include a cost-effectiveness analysis.

Therapeutic Approaches Targeting Ferroptosis in Cardiomyopathy

The term cardiomyopathy refers to a group of heart diseases that cause severe heart failure over time. Cardiomyopathies have been proven to be associated with ferroptosis, a non-apoptotic form of cell death. It has been shown that some small molecule drugs and active ingredients of herbal medicine can regulate ferroptosis, thereby alleviating the development of cardiomyopathy. This article reviews recent discoveries about ferroptosis, its role in the pathogenesis of cardiomyopathy, and the therapeutic options for treating ferroptosis-associated cardiomyopathy. The article aims to provide insights into the basic mechanisms of ferroptosis and its treatment to prevent cardiomyopathy and related diseases.

T2* map at cardiac MRI reveals incidental hepatic and cardiac iron overload

PURPOSE

The purpose of this study was to assess the diagnostic capabilities of cardiac magnetic resonance (CMR) T2* mapping in detecting incidental hepatic and cardiac iron overload.

MATERIALS AND METHODS

Patients with various clinical indications for CMR examination were consecutively included at a single center from January 2019 to April 2023. All patients underwent T2* mapping at 1.5 T in a single mid-ventricular short-axis as part of a comprehensive routine CMR protocol. T2* measurements were performed of the heart (using a region-of-interest in the interventricular septum) and the liver, categorized according to the severity of iron overload. The degree of cardiac iron overload was categorized as mild (15 ms < T2* < 20 ms), moderate (10 ms < T2* < 15 ms) and severe (T2* < 10 ms). The degree of hepatic iron overload was categorized as mild (4 ms < T2* < 8 ms), moderate (2 ms < T2* < 4 ms), severe (T2* < 2 ms). Image quality and inter-reader agreement were assessed using intraclass correlation coefficient (ICC).

RESULTS

CMR examinations from 614 patients (374 men, 240 women) with a mean age of 50 ± 18 (standard deviation) years were fully evaluable. A total of 24/614 patients (3.9%) demonstrated incidental hepatic iron overload; of these, 22/614 patients (3.6%) had mild hepatic iron overload, and 2/614 patients (0.3%) had moderate hepatic iron overload. Seven out of 614 patients (1.1%) had incidental cardiac iron overload; of these, 5/614 patients (0.8%) had mild iron overload, 1/614 patients (0.2%) had moderate iron overload, and 1/614 patients (0.2%) had severe iron overload. Good to excellent inter-reader agreement was observed for the assessment of T2* values (ICC, 0.90 for heart [95% confidence interval: 0.88-0.91]; ICC, 0.91 for liver [95% confidence interval: 0.89-0.92]).

CONCLUSION

Analysis of standard CMR T2* maps detects incidental cardiac and hepatic iron overload in 1.1% and 3.9% of patients, respectively, which may have implications for further patient management. Therefore, despite an overall low number of incidental abnormal findings, T2* imaging may be included in a standardized comprehensive CMR protocol.

Sheng-Mai-Yin inhibits doxorubicin-induced ferroptosis and cardiotoxicity through regulation of Hmox1

Doxorubicin (DOX) is a potent chemotherapeutic drug used for treating various cancers. However, its clinical use is limited due to its severe cardiotoxicity, which often results in high mortality rates. Sheng-Mai-Yin (SMY), a Traditional Chinese medicine (TCM) prescription, has been reported to exert a cardioprotective effect in various cardiovascular diseases, including DOX-induced cardiotoxicity (DIC). This study aimed to provide novel insights into the underlying cardioprotective mechanism of SMY. SMY, composed of Codonopsis pilosula (Franch.), Ophiopogon japonicus (Thunb.), and Schisandra chinensis (Turcz.) at a ratio of 3:2:1, was intragastrically administered to male C57BL/6 mice for five days prior to the intraperitoneal injection of mitoTEMPO. One day later, DOX was intraperitoneally injected. Hematoxylin-eosin staining and Sirius red staining were carried out to estimate the pharmacological effect of SMY on cardiotoxicity. Mitochondrial function and ferroptosis biomarkers were also examined. AAV was utilized to overexpress Hmox1 to confirm whether Hmox1-mediated ferroptosis is associated with the cardioprotective effect of SMY on DOX-induced cardiotoxicity. The findings revealed that SMY therapy reduced the number of damaged cardiomyocytes. SMY therapy also reversed the inductions of cardiac MDA, serum MDA, LDH, and CK-MB contents, which dramatically decreased nonheme iron levels. In the meantime, SMY corrected the changes to ferroptosis indices brought on by DOX stimulation. Additionally, Hmox1 overexpression prevented SMY's ability to reverse cardiotoxicity. Our results showed that SMY effectively restrained lipid oxidation, reduced iron overload, and inhibited DOX-induced ferroptosis and cardiotoxicity, possibly via the mediation of Hmox1.

MitoNEET prevents iron overload-induced insulin resistance in H9c2 cells through regulation of mitochondrial iron

Iron overload (IO) induces insulin resistance in H9c2 cardiomyoblast cells. Here, we used H9c2 cells overexpressing MitoNEET to examine the potential for protection against iron accumulation in the mitochondria and subsequent insulin resistance. In control H9c2 cells, IO was observed to increase mitochondrial iron content, reactive oxygen species (ROS) production, mitochondrial fission, and reduced insulin-stimulated Akt and ERK1/2 phosphorylation. IO did not significantly affect mitophagy, or mitochondrial content, however, an increase in peroxisome-proliferator-activated receptor gamma coactivator 1 alpha (PGC1α) protein expression, a key regulator of mitochondrial biogenesis, was observed. MitoNEET overexpression was able to attenuate the effects of IO on mitochondrial iron content, reactive oxygen species, mitochondrial fission, and insulin signaling. MitoNEET overexpression also upregulated levels of PGC1α protein. The mitochondria-targeted antioxidant, Skq1, prevented IO-induced ROS production and insulin resistance in control cells, indicating mitochondrial ROS plays a causal role in the onset of insulin resistance. The selective mitochondrial fission inhibitor, Mdivi-1, prevented IO-induced mitochondrial fission, however, it did not alleviate IO-induced insulin resistance. Collectively, IO causes insulin resistance in H9c2 cardiomyoblasts and this can be averted by reduction of mitochondrial iron accumulation and ROS production by overexpression of the MitoNEET protein.

Risk factors for fatal cardiac complications after allogeneic hematopoietic cell transplantation: Japanese Society for Transplantation and Cellular Therapy transplant complications working group

Fatal cardiac complications can occur from the early to late phases after hematopoietic cell transplantation (HCT). Herein, the Japanese transplant registry database was used to retrospectively analyze health records of 33,791 allogeneic HCT recipients to elucidate the pathogenesis and risk factors involved. Overall, 527 patients died of cardiac complications at a median of 130 (range 0-3924) days after HCT. The cumulative incidence of fatal cardiac complications was 1.2% (95% confidence interval [CI]: 1.0-1.3) and 1.6% (95% CI: 1.5-1.8) at 1 and 5 years after HCT, respectively. Fatal cardiovascular events were significantly associated with an HCT-specific comorbidity index (HCT-CI) score of ≥1 specific to the three cardiovascular items, lower performance status, conditioning regimen cyclophosphamide dose of >120 mg/kg, and female sex. Cardiovascular death risk within 60 days after HCT was associated with the type of conditioning regimen, presence of bacterial or fungal infections at HCT, and number of blood transfusions. Contrastingly, late cardiovascular death beyond 1 year after HCT was associated with female sex and older age. Lower performance status and positive cardiovascular disease-related HCT-CI were risk factors for cardiac complications in all phases after HCT. Systematic follow-up may be necessary according to the patients' risk factors and conditions.

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

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

Circular RNA FEACR inhibits ferroptosis and alleviates myocardial ischemia/reperfusion injury by interacting with NAMPT

BACKGROUND

Emerging research has reported that circular RNAs (circRNAs) play important roles in cardiac cell death after myocardial ischemia and reperfusion (I/R). Ferroptosis, a new form of cell death discovered in recent years, has been proven to participate in the regulation of myocardial I/R. This study used circRNA sequencing to explore the key circRNA in the regulation of cardiac ferroptosis after I/R and study the mechanisms of potential circRNA function.

METHODS

We performed circRNA sequencing to explore circRNAs differentially expressed after myocardial I/R. We used quantitative polymerase chain reactions to determine the circRNA expression in different tissues and detect the circRNA subcellular localization in the cardiomyocyte. Gain- and loss-of-function experiments were aimed to examine the function of circRNAs in cardiomyocyte ferroptosis and cardiac tissue damage after myocardial I/R. RNA pull-down was applied to explore proteins interacting with circRNA.

RESULTS

Here, we identified a ferroptosis-associated circRNA (FEACR) that has an underlying regulatory role in cardiomyocyte ferroptosis. FEACR overexpression suppressed I/R-induced myocardial infarction and ameliorated cardiac function. FEACR inhibition induces ferroptosis in cardiomyocytes and FEACR overexpression inhibits hypoxia and reoxygenation-induced ferroptosis. Mechanistically, FEACR directly bound to nicotinamide phosphoribosyltransferase (NAMPT) and enhanced the protein stability of NAMPT, which increased NAMPT-dependent Sirtuin1 (Sirt1) expression, which promoted the transcriptional activity of forkhead box protein O1 (FOXO1) by reducing FOXO1 acetylation levels. FOXO1 further upregulated the transcription of ferritin heavy chain 1 (Fth1), a ferroptosis suppressor, which resulted in the inhibition of cardiomyocyte ferroptosis.

CONCLUSIONS

Our finding reveals that the circRNA FEACR-mediated NAMPT-Sirt1-FOXO1-FTH1 signaling axis participates in the regulation of cardiomyocyte ferroptosis and protects the heart function against I/R injury. Thus, FEACR and its downstream factors could be novel targets for alleviating ferroptosis-related myocardial injury in ischemic heart diseases.

Cardiac magnetic resonance of hypertrophic heart phenotype: A review

Hypertrophic heart phenotype is characterized by an abnormal left ventricular (LV) thickening. A hypertrophic phenotype can develop as adaptive response in many different conditions such as aortic stenosis, hypertension, athletic training, infiltrative heart muscle diseases, storage disorders and metabolic disorders. Hypertrophic cardiomyopathy (HCM) is the most frequent primary cardiomyopathy (CMP) and a genetical cause of cardiac hypertrophy. It requires the exclusion of any other cause of LV hypertrophy. Cardiac magnetic resonance (CMR) is a comprehensive imaging technique that allows a detailed evaluation of myocardial diseases. It provides reproducible measurements and myocardial tissue characterization. In clinical practice CMR is increasingly used to confirm the presence of ventricular hypertrophy, to detect the underlying cause of the phenotype and more recently as an efficient prognostic tool. This article aims to provide a detailed overview of the applications of CMR in the setting of hypertrophic heart phenotype and its role in the diagnostic workflow of such condition.

Deficiency of mitochondrial calcium uniporter abrogates iron overload-induced cardiac dysfunction by reducing ferroptosis

Iron overload associated cardiac dysfunction remains a significant clinical challenge whose underlying mechanism(s) have yet to be defined. We aim to evaluate the involvement of the mitochondrial Ca2+ uniporter (MCU) in cardiac dysfunction and determine its role in the occurrence of ferroptosis. Iron overload was established in control (MCUfl/fl) and conditional MCU knockout (MCUfl/fl-MCM) mice. LV function was reduced by chronic iron loading in MCUfl/fl mice, but not in MCUfl/fl-MCM mice. The level of mitochondrial iron and reactive oxygen species were increased and mitochondrial membrane potential and spare respiratory capacity (SRC) were reduced in MCUfl/fl cardiomyocytes, but not in MCUfl/fl-MCM cardiomyocytes. After iron loading, lipid oxidation levels were increased in MCUfl/fl, but not in MCUfl/fl-MCM hearts. Ferrostatin-1, a selective ferroptosis inhibitor, reduced lipid peroxidation and maintained LV function in vivo after chronic iron treatment in MCUfl/fl hearts. Isolated cardiomyocytes from MCUfl/fl mice demonstrated ferroptosis after acute iron treatment. Moreover, Ca2+ transient amplitude and cell contractility were both significantly reduced in isolated cardiomyocytes from chronically Fe treated MCUfl/fl hearts. However, ferroptosis was not induced in cardiomyocytes from MCUfl/fl-MCM hearts nor was there a reduction in Ca2+ transient amplitude or cardiomyocyte contractility. We conclude that mitochondrial iron uptake is dependent on MCU, which plays an essential role in causing mitochondrial dysfunction and ferroptosis under iron overload conditions in the heart. Cardiac-specific deficiency of MCU prevents the development of ferroptosis and iron overload-induced cardiac dysfunction.

Nature-Inspired Bioactive Compounds: A Promising Approach for Ferroptosis-Linked Human Diseases?

Ferroptosis is a type of cell death driven by iron overload and lipid peroxidation. It is considered a key mechanism in the development of various diseases such as atherosclerosis, Alzheimer, diabetes, cancer, and renal failure. The redox status of cells, such as the balance between intracellular oxidants (lipid peroxides, reactive oxygen species, free iron ions) and antioxidants (glutathione, glutathione Peroxidase 4), plays a major role in ferroptosis regulation and constitutes its principal biomarkers. Therefore, the induction and inhibition of ferroptosis are promising strategies for disease treatments such as cancer or neurodegenerative and cardiovascular diseases, respectively. Many drugs have been developed to exert ferroptosis-inducing and/or inhibiting reactions, such as erastin and iron-chelating compounds, respectively. In addition, many natural bioactive compounds have significantly contributed to regulating ferroptosis and ferroptosis-induced oxidative stress. Natural bioactive compounds are largely abundant in food and plants and have been for a long time, inspiring the development of various low-toxic therapeutic drugs. Currently, functional bioactive peptides are widely reported for their antioxidant properties and application in human disease treatment. The scientific evidence from biochemical and in vitro tests of these peptides strongly supports the existence of a relationship between their antioxidant properties (such as iron chelation) and ferroptosis regulation. In this review, we answer questions concerning ferroptosis milestones, its importance in physiopathology mechanisms, and its downstream regulatory mechanisms. We also address ferroptosis regulatory natural compounds as well as provide promising thoughts about bioactive peptides.

New Insights into the Role of Ferroptosis in Cardiovascular Diseases

Cardiovascular diseases (CVDs) are the principal cause of disease burden and death worldwide. Ferroptosis is a new form of regulated cell death mainly characterized by altered iron metabolism, increased polyunsaturated fatty acid peroxidation by reactive oxygen species, depletion of glutathione and inactivation of glutathione peroxidase 4. Recently, a series of studies have indicated that ferroptosis is involved in the death of cardiac and vascular cells and has a key impact on the mechanisms leading to CVDs such as ischemic heart disease, ischemia/reperfusion injury, cardiomyopathies, and heart failure. In this article, we reviewed the molecular mechanism of ferroptosis and the current understanding of the pathophysiological role of ferroptosis in ischemic heart disease and in some cardiomyopathies. Moreover, the comprehension of the machinery governing ferroptosis in vascular cells and cardiomyocytes may provide new insights into preventive and therapeutic strategies in CVDs.

Mechanism of YY1 mediating autophagy dependent ferroptosis in PM2.5 induced cardiac fibrosis

Epidemiological studies have demonstrated strong associations between exposure to ambient fine particulate matter (PM2.5) and cardiac disease. To investigate the potential mechanism of cardiac fibrosis induced by PM2.5, we established PM2.5 exposure models in vivo and in vitro, and then cardiac fibrosis was evaluated. The ferroptosis and ferritinophagy was detected to characterize the effects of PM2.5 exposure. The results indicated that PM2.5 exposure could induce cardiac fibrosis in mice. YY1 was induced by PM2.5 exposure and then increased NCOA4, a cargo receptor for ferritinophagy, which interacted with FHC and promoted the transport of ferritin to the autophagosome for degradation. The release of large amounts of free iron from ferritinophagy led to lipid peroxidation directly via the Fenton reaction, thereby triggering ferroptosis. Moreover, siNCOA4 could partly restore the FHC protein level in HL-1 cells and inhibit the occurrence of downstream ferroptosis. Functionally, NCOA4 knockdown inhibited ferroptosis and alleviated HL-1 cell death induced by PM2.5. Ferroptosis inhibitor (Ferrostatin-1) could reverse the promoting effect of ferritinophagy mediated ferroptosis on cardiac fibrosis induced by PM2.5 exposure in mice. Our study indicated that PM2.5 induced cardiac fibrosis through YY1 regulating ferritinophagy-dependent ferroptosis.

Understanding the mechanistic roles of environmental heavy metal stressors in regulating ferroptosis: adding new paradigms to the links with diseases

Ferroptosis is a new type of iron-dependent cell death induced by a failure of the lipid repair protein GPX4 or the Xc- antiporter, which is essential for glutathione production. Some heavy metals such as arsenic (As), cobalt (Co), cadmium (Cd), iron (Fe), magnesium (Mg), manganese (Mn), nickel (Ni), mercury (Hg) as well as zinc (Zn) are shown to induce ferroptotic cell death involving the generation of oxidative stress, mitochondrial dysfunctioning, lipid peroxidation, and several other cellular etiologies. However, selenium (Se) treatment has been shown to enhance adaptive transcription responses to protect cells from ferroptosis. Heavy metals like Cadmium exposure activated ALK4/5 signaling via Smad3 and Akt signaling which leads to cell death mechanism. Continuous exposure to a small dose of mercury can damage tissues, and methylmercury bind to sulfhydryl proteins and GSH, this elevates oxidative stress, free radical accumulation, glutathione depletion, mitochondrial damage, and inhibited the nuclear factor-κB pathway which leads to ferroptotic cell death. Animals exposed to nickel and cobalt may have increased lipid peroxidation which can induce ferroptosis. Glutathione depletion is caused by Zn intoxication and exposure to manganese. These metals are systemic toxins that have been shown adverse effects on humans. Ferroptosis has recently been related to several pathological disorders, including, Alzheimer's disease, Parkinson's disease, Huntington's disease, as well as cardiovascular disease, and any type of cancer. For these disorders and some heavy metal toxicity, ferroptosis suppression needs to be looked upon as a promising therapeutic choice.

Amlodipine rescues advanced iron overload cardiomyopathy in hemojuvelin knockout murine model: Clinical implications

Background

Iron overload cardiomyopathy (IOC) is a major co-morbidity of genetic hemochromatosis and secondary iron overload with limited therapeutic options. We aim to investigate mechanisms of rescue action of amlodipine in the murine model of iron overload, characterize changes in human cardiac tissue due to IOC, and compare them to the changes in the animal model of IOC.

Methods and results

As an animal model, we used male hemojuvelin knockout (HJVKO) mice, which lacked hemojuvelin (a co-receptor protein for hepcidin expression). The mice were fed a high-iron diet from 4 weeks to 1 year of age. As a rescue, iron-fed mice received the Ca²⁺ channel blocker, amlodipine, from 9 to 12 months. Iron overload resulted in systolic and diastolic dysfunctions and changes in the cardiac tissue similar to the changes in the explanted human heart with IOC. An IOC patient (β-thalassemia) with left-ventricular ejection fraction (LVEF) 25% underwent heart transplantation. The murine model and the explanted heart showed intra-myocyte iron deposition, fibrosis, hypertrophy, oxidative stress, remodeling of Ca²⁺ cycling proteins, and metabolic kinases typical of heart failure. Single-myocyte contractility and Ca²⁺ release were diminished in the murine model. The amlodipine-treated group exhibited normalization of cellular function and reversed fibrosis, hypertrophy, oxidative stress, and metabolic remodeling. We also report a clinical case of primary hemochromatosis successfully treated with amlodipine.

Conclusions

The aged HJVKO murine model on the iron-rich diet reproduced many features of the human case of IOC. The use of amlodipine in the murine model and clinical case reversed IOC remodeling, demonstrating that amlodipine is effective adjuvant therapy for IOC.

Association between serum ferritin and bone mineral density in US adults

Background

The association between serum ferritin and bone mineral density (BMD) is still controversial. This study aims to investigate the association of serum ferritin level with BMD in US adults.

Methods

We conducted a cross-sectional study consisting of 8445 participants from National Health and Nutrition Examination Survey. Serum ferritin and lumbar spine BMD were used as independent variables and dependent variables, respectively. We evaluated the association between serum ferritin and lumbar spine BMD through a weighted multivariable linear regression model. Subgroup and interaction analysis was also performed in this study.

Results

After adjusting for other confounding factors, serum ferritin was negatively correlated with lumbar spine BMD [β =  − 0.090, 95% CI (− 0.135, − 0.045)]. Further subgroup analysis found that the strongest negative association mainly exists in females aged over 45 years [β =  − 0.169, 95% CI (− 0.259, − 0.079)], and this association is not significant in other groups.

Conclusions

The results found that the association between serum ferritin and lumber spine BMD differed by gender and age. Increased level of serum ferritin may indicate a higher risk of osteoporosis or osteopenia in females aged over 45 years.

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.

Restrictive cardiomyopathy: definition and diagnosis

Restrictive cardiomyopathy (RCM) is a heterogeneous group of diseases characterized by restrictive left ventricular pathophysiology, i.e. a rapid rise in ventricular pressure with only small increases in filling volume due to increased myocardial stiffness. More precisely, the defining feature of RCM is the coexistence of persistent restrictive pathophysiology, diastolic dysfunction, non-dilated ventricles, and atrial dilatation, regardless of ventricular wall thickness and systolic function. Beyond this shared haemodynamic hallmark, the phenotypic spectrum of RCM is wide. The disorders manifesting as RCM may be classified according to four main disease mechanisms: (i) interstitial fibrosis and intrinsic myocardial dysfunction, (ii) infiltration of extracellular spaces, (iii) accumulation of storage material within cardiomyocytes, or (iv) endomyocardial fibrosis. Many disorders do not show restrictive pathophysiology throughout their natural history, but only at an initial stage (with an evolution towards a hypokinetic and dilated phenotype) or at a terminal stage (often progressing from a hypertrophic phenotype). Furthermore, elements of both hypertrophic and restrictive phenotypes may coexist in some patients, making the classification challenge. Restrictive pathophysiology can be demonstrated by cardiac catheterization or Doppler echocardiography. The specific conditions may usually be diagnosed based on clinical data, 12-lead electrocardiogram, echocardiography, nuclear medicine, or cardiovascular magnetic resonance, but further investigations may be needed, up to endomyocardial biopsy and genetic evaluation. The spectrum of therapies is also wide and heterogeneous, but disease-modifying treatments are available only for cardiac amyloidosis and, partially, for iron overload cardiomyopathy.

Cardiac Magnetic Resonance at 3.0 T in Patients With C282Y Homozygous Hereditary Hemochromatosis: Superiority of Radial and Circumferential Strain Over Cardiac T2* Measurements at Baseline and at Post Venesection Follow-up

BACKGROUND

Iron-overload cardiomyopathy initially manifests with diastolic dysfunction and can progress to dilated cardiomyopathy if untreated. Previous studies have shown that patients with primary and secondary hemochromatosis can have subclinical left ventricle dysfunction with abnormalities on strain imaging. This study aimed to evaluate the relationship between cardiac T2* values and myocardial-wall strain in patients with hereditary hemochromatosis (HH) at the time of diagnosis and after a course of venesection treatment.

MATERIALS AND METHODS

Baseline cardiac magnetic resonance (CMR) at 3 T was performed in 19 patients with newly diagnosed HH with elevated serum ferritin levels and repeated after a course of treatment with venesection. Quantitative T2* mapping and strain analysis were performed offline using dedicated relaxometry fitting and feature-tracking software.

RESULTS

The majority (84%) of patients had normal baseline myocardial T2* values (mean 19.3 ms, range 8.9 to 31.2 ms), which improved significantly after venesection (mean 24.1 ms, range 11 to 38.1 ms) ( P =0.021). Mean global radial strain significantly improved from 25.0 (range: 15.6 to 32.9) to 28.3 (range: 19.8 to 35.8) ( P =0.001) and mean global circumferential strain improved, decreasing from -15.7 (range: -11.1 to -19.2) to -17.1 (range: -13.0 to -20.1) ( P =0.001).

CONCLUSION

Patients with HH may have normal T2* values in the presence of subclinical left ventricle dysfunction, which can be detected by abnormal radial and circumferential strain. As strain imaging improves following venesection in HH, it may serve as a useful biomarker to guide treatment.

Cardiovascular consequences of sickle cell disease

Sickle cell disease (SCD) is an inherited blood disorder caused by a single point mutation within the beta globin gene. As a result of this mutation, hemoglobin polymerizes under low oxygen conditions causing red blood cells to deform, become more adhesive, and increase in rigidity, which affects blood flow dynamics. This process leads to enhanced red blood cell interactions with the endothelium and contributes to vaso-occlusion formation. Although traditionally defined as a red blood cell disorder, individuals with SCD are affected by numerous clinical consequences including stroke, painful crisis episodes, bone infarctions, and several organ-specific complications. Elevated cardiac output, endothelium activation along with the sickling process, and the vaso-occlusion events pose strains on the cardiovascular system. We will present a review of the cardiovascular consequences of sickle cell disease and show connections with the vasculopathy related to SCD. We will also highlight biophysical properties and engineering tools that have been used to characterize the disease. Finally, we will discuss therapies for SCD and potential implications on SCD cardiomyopathy.

Molecular Mechanisms of Ferroptosis and Relevance to Cardiovascular Disease

Ferroptosis has recently been demonstrated to be a novel regulated non-apoptotic cell death characterized by iron-dependence and the accumulation of lipid peroxidation that results in membrane damage. Excessive iron induces ferroptosis by promoting the generation of both soluble and lipid ROS via an iron-dependent Fenton reaction and lipoxygenase (LOX) enzyme activity. Cytosolic glutathione peroxidase 4 (cGPX4) pairing with ferroptosis suppressor protein 1 (FSP1) and mitochondrial glutathione peroxidase 4 (mGPX4) pairing with dihydroorotate dehydrogenase (DHODH) serve as two separate defense systems to detoxify lipid peroxidation in the cytoplasmic as well as the mitochondrial membrane, thereby defending against ferroptosis in cells under normal conditions. However, disruption of these defense systems may cause ferroptosis. Emerging evidence has revealed that ferroptosis plays an essential role in the development of diverse cardiovascular diseases (CVDs), such as hemochromatosis-associated cardiomyopathy, doxorubicin-induced cardiotoxicity, ischemia/reperfusion (I/R) injury, heart failure (HF), atherosclerosis, and COVID-19–related arrhythmias. Iron chelators, antioxidants, ferroptosis inhibitors, and genetic manipulations may alleviate the aforementioned CVDs by blocking ferroptosis pathways. In conclusion, ferroptosis plays a critical role in the pathogenesis of various CVDs and suppression of cardiac ferroptosis is expected to become a potential therapeutic option. Here, we provide a comprehensive review on the molecular mechanisms involved in ferroptosis and its implications in cardiovascular disease.

Ferroptosis and its role in cardiomyopathy

Heart disease is the leading cause of death worldwide. Cardiomyopathy is a disease characterized by the heart muscle damage, resulting heart in a structurally and functionally change, as well as heart failure and sudden cardiac death. The key pathogenic factor of cardiomyopathy is the loss of cardiomyocytes, but the related molecular mechanisms remain unclear. Ferroptosis is a newly discovered regulated form of cell death, characterized by iron accumulation and lipid peroxidation during cell death. Recent studies have shown that ferroptosis plays an important regulatory roles in the occurrence and development of many heart diseases such as myocardial ischemia/reperfusion injury, cardiomyopathy and heart failure. However, the systemic association of ferroptosis and cardiomyopathy remains largely unknown and needs to be elucidated. In this review, we provide an overview of the molecular mechanisms of ferroptosis and its role in individual cardiomyopathies, highlight that targeting ferroptosis maybe a potential therapeutic strategy for cardiomyopathy therapy in the future.

Cardiac MRI of Hereditary Cardiomyopathy

Hereditary cardiomyopathy comprises a heterogeneous group of diseases of the cardiac muscle that are characterized by the presence of genetic mutations. Cardiac MRI is central to evaluation of patients with cardiomyopathy owing to its ability to allow evaluation of many different tissue properties in a single examination. For example, cine MRI is the standard of care for assessment of myocardial structure and function. It clearly shows regions of asymmetric wall thickening that are typical of hypertrophic cardiomyopathy and allows it to be differentiated from other hereditary disorders such as Fabry disease or transthyretin cardiac amyloidosis that produce concentric hypertrophy. Late gadolinium enhancement provides a different tissue property and allows these latter two causes of concentric hypertrophy to be distinguished on the basis of their enhancement appearances (Fabry disease shows midwall basal inferolateral enhancement, and amyloidosis shows global subendocardial enhancement). Native T1 mapping may similarly allow differentiation between Fabry disease and amyloidosis without the use of contrast material. T2*-weighted MRI is important in the detection and quantification of iron overload cardiomyopathy. Other hereditary entities for which comprehensive MRI has proven essential include Danon disease, familial dilated cardiomyopathy, hereditary muscular dystrophy, arrhythmogenic right ventricular cardiomyopathy, and ventricular noncompaction. As a result of the diagnostic power of cardiac MRI, cardiac MRI examinations are being requested with increasing frequency, not only in academic centers but also in community practices. The genetic background, pathophysiologic characteristics, and clinical presentation of patients with hereditary cardiomyopathy are described; the characteristic cardiac MRI features of hereditary cardiomyopathy are discussed; and the role of MRI in risk stratification, treatment, and prognostication in patients with cardiomyopathy is reviewed. ^©RSNA, 2022 Online supplemental material is available for this article.

Iron promotes Slc7a11-deficient valvular interstitial cell osteogenic differentiation: A possible mechanism by which ferroptosis participates in intraleaflet hemorrhage-induced calcification

Calcific aortic valve disease (CAVD) is the most frequent pathogeny of aortic valve replacement in developed countries. Iron deposits are found in the intraleaflet hemorrhage (IH) areas of calcific aortic valves. Ferroptosis is a form of regulated cell death that involves metabolic dysfunction resulting from iron overload-dependent excessive lipid peroxidation. In this study, histological analysis showed that ferroptosis occurs in the IH areas of calcific aortic valves. We also demonstrated that Slc7a11 is expressed at low levels in OM-treated valvular interstitial cells (VICs) and IH areas and that low Slc7a11 expression is associated with calcification in CAVD. However, iron overload treatment did not promote VIC calcification under osteogenic conditions in vitro. Using lentiviral transfection to knockdown Slc7a11 in VICs, we found that the degree of iron overload-induced ferroptosis was positively increased in vitro. Finally, we also found that Slc7a11 knockdown promoted the osteogenic differentiation of VICs in vitro. In summary, this study reports a novel mechanism linking ferroptosis and CAVD development in which iron may promote Slc7a11-deficient VIC osteogenic differentiation by aggravating ferroptosis in vitro, thereby accelerating the progression of aortic valve calcification.

Role of Iron in Aging Related Diseases

Iron progressively accumulates with age and can be further exacerbated by dietary iron intake, genetic factors, and repeated blood transfusions. While iron plays a vital role in various physiological processes within the human body, its accumulation contributes to cellular aging in several species. In its free form, iron can initiate the formation of free radicals at a cellular level and contribute to systemic disorders. This is most evident in high iron conditions such as hereditary hemochromatosis, when accumulation of iron contributes to the development of arthritis, cirrhosis, or cardiomyopathy. A growing body of research has further identified iron’s contributory effects in neurodegenerative diseases, ocular disorders, cancer, diabetes, endocrine dysfunction, and cardiovascular diseases. Reducing iron levels by repeated phlebotomy, iron chelation, and dietary restriction are the common therapeutic considerations to prevent iron toxicity. Chelators such as deferoxamine, deferiprone, and deferasirox have become the standard of care in managing iron overload conditions with other potential applications in cancer and cardiotoxicity. In certain animal models, drugs with iron chelating ability have been found to promote health and even extend lifespan. As we further explore the role of iron in the aging process, iron chelators will likely play an increasingly important role in our health.

Signaling cascades in the failing heart and emerging therapeutic strategies

Chronic heart failure is the end stage of cardiac diseases. With a high prevalence and a high mortality rate worldwide, chronic heart failure is one of the heaviest health-related burdens. In addition to the standard neurohormonal blockade therapy, several medications have been developed for chronic heart failure treatment, but the population-wide improvement in chronic heart failure prognosis over time has been modest, and novel therapies are still needed. Mechanistic discovery and technical innovation are powerful driving forces for therapeutic development. On the one hand, the past decades have witnessed great progress in understanding the mechanism of chronic heart failure. It is now known that chronic heart failure is not only a matter involving cardiomyocytes. Instead, chronic heart failure involves numerous signaling pathways in noncardiomyocytes, including fibroblasts, immune cells, vascular cells, and lymphatic endothelial cells, and crosstalk among these cells. The complex regulatory network includes protein-protein, protein-RNA, and RNA-RNA interactions. These achievements in mechanistic studies provide novel insights for future therapeutic targets. On the other hand, with the development of modern biological techniques, targeting a protein pharmacologically is no longer the sole option for treating chronic heart failure. Gene therapy can directly manipulate the expression level of genes; gene editing techniques provide hope for curing hereditary cardiomyopathy; cell therapy aims to replace dysfunctional cardiomyocytes; and xenotransplantation may solve the problem of donor heart shortages. In this paper, we reviewed these two aspects in the field of failing heart signaling cascades and emerging therapeutic strategies based on modern biological techniques.

Overview of Restrictive Cardiomyopathies

Restrictive cardiomyopathy (RCM) includes a heterogeneous group of diseases that cause increased myocardial stiffness, leading to impaired ventricular relaxation and severe diastolic dysfunction. Given that it is the least common type of cardiomyopathy, it can be a diagnostic challenge due to its varied pathogenesis, clinical presentation, and diagnostic evaluation. In this review, we provide an overview of different etiologies of RCM and examine the diagnostic and treatment approaches for various types.

Ferroptosis due to Cystathionine γ Lyase/Hydrogen Sulfide Downregulation Under High Hydrostatic Pressure Exacerbates VSMC Dysfunction

Hydrostatic pressure, stretch, and shear are major biomechanical forces of vessels and play critical roles in genesis and development of hypertension. Our previous work demonstrated that high hydrostatic pressure (HHP) promoted vascular smooth muscle cells (VSMCs) two novel subsets: inflammatory and endothelial function inhibitory VSMCs and then exacerbated VSMC dysfunction. However, the underlying mechanism remains unknown. Here, we first identified that aortic GPX4 (a core regulator of ferroptosis) significantly downregulated association with VSMC novel phenotype elevation in SHR rats and hypertension patients. In primary VSMCs, HHP (200 mmHg) increased iron accumulation, ROS production, and lipid peroxidation compared with normal pressure (100 mmHg). Consistently, the ferroptosis-related gene (COX-2, TFRC, ACSL4, and NOX-1) expression was also upregulated. The ferroptosis inhibitor ferrostatin-1 (Fer-1) administration blocked HHP-induced VSMC inflammatory (CXCL2 expression) and endothelial function inhibitory (AKR1C2 expression) phenotyping switch association with elevation in the GPX4 expression, reduction in the reactive oxygen species (ROS), and lipid peroxidation production. In contrast, the ferroptosis inducer RLS3 increased HHP-induced CXCL2 and AKR1C2 expressions. These data indicate HHP-triggering ferroptosis contributes to VSMC inflammatory and endothelial function inhibitory phenotyping switch. In mechanism, HHP reduced the VSMC GSH content and cystathionine gamma-lyase (CSE)/hydrogen sulfide (H₂S)—an essential system for GSH generation. Supplementation of the H₂S donor-NaHS increased the VSMC GSH level, alleviated iron deposit, ROS and lipid peroxidation production. NaHS administration rescues both HHP- and RLS3-induced ferroptosis. Collectively, HHP downregulated VSMC CSE/H₂S triggering GSH level reduction, resulting in ferroptosis, which contributed to the genesis of VSMC inflammation and endothelial function inhibitory phenotypes.

Combined heart and liver transplantation: an updated systematic review

INTRODUCTION

Combined heart and liver transplantation (CHLT) is one of the most complex procedures of surgery that has been implemented in the last 35 years. The aim of our meta-analysis was to investigate the safety and efficacy of CHLT.

MATERIALS

The meta-analysis was designed according to PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses) and AMSTAR (A MeaSurement Tool to Assess systematic Reviews) recommendations. A literature search was conducted up to April 2020 using the MEDLINE,® SCOPUS,® ClinicalTrials.gov, Embase™, Cochrane Central Register of Controlled Trials and Google Scholar™ databases.

RESULTS

Our meta-analysis included 16 studies with 860 patients. The mortality rate following CHLT was 14.1%. One and five-year survival rates were 85.3% and 71.4% while the heart and liver rejection rates were 6.1% and 9.1% respectively. The hospital stay was 25.8 days and the intensive care unit stay was 9.9 days. Pooled values were also calculated for cardiopulmonary bypass duration, units of transfused red blood cells and fresh frozen plasma, postoperative infection rate, mechanical ventilation rate and follow-up duration.

CONCLUSIONS

Despite its complexity, CHLT is a safe and effective procedure for the management of lethal diseases that lead to progressive heart and/or liver failure. Nevertheless, there must be strict adherence to the indications for surgery, and future studies should compare CHLT with isolated cardiac and hepatic transplantations.

Multimodality Cardiac Imaging in Cardiomyopathies: From Diagnosis to Prognosis

Cardiomyopathies are a group of structural and/or functional myocardial disorders which encompasses hypertrophic, dilated, arrhythmogenic, restrictive, and other cardiomyopathies. Multimodality cardiac imaging techniques are the cornerstone of cardiomyopathy diagnosis; transthoracic echocardiography should be the first-line imaging modality due to its availability, and diagnosis should be confirmed by cardiovascular magnetic resonance, which will provide more accurate morphologic and functional information, as well as extensive tissue characterization. Multimodality cardiac imaging techniques are also essential in assessing the prognosis of patients with cardiomyopathies; left ventricular ejection fraction and late gadolinium enhancement are two of the main variables used for risk stratification, and they are incorporated into clinical practice guidelines. Finally, periodic testing with cardiac imaging techniques should also be performed due to the evolving and progressive natural history of most cardiomyopathies.

Coordination of iron homeostasis by bone morphogenetic proteins: Current understanding and unanswered questions

Iron homeostasis is tightly regulated to balance the iron requirement for erythropoiesis and other vital cellular functions, while preventing cellular injury from iron excess. The liver hormone hepcidin is the master regulator of systemic iron balance by controlling the degradation and function of the sole known mammalian iron exporter ferroportin. Liver hepcidin expression is coordinately regulated by several signals that indicate the need for more or less iron, including plasma and tissue iron levels, inflammation, and erythropoietic drive. Most of these signals regulate hepcidin expression by modulating the activity of the bone morphogenetic protein (BMP)-SMAD pathway, which controls hepcidin transcription. Genetic disorders of iron overload and iron deficiency have identified several hepatocyte membrane proteins that play a critical role in mediating the BMP-SMAD and hepcidin regulatory response to iron. However, the precise molecular mechanisms by which serum and tissue iron levels are sensed to regulate BMP ligand production and promote the physical and/or functional interaction of these proteins to modulate SMAD signaling and hepcidin expression remain uncertain. This critical commentary will focus on the current understanding and key unanswered questions regarding how the liver senses iron levels to regulate BMP-SMAD signaling and thereby hepcidin expression to control systemic iron homeostasis.

Herceptin induces ferroptosis and mitochondrial dysfunction in H9c2 cells

Ferroptosis has been previously implicated in the pathological progression of cardiomyopathy. Herceptin (trastuzumab), which targets HER2, is commonly applied for the treatment of HER2⁺ breast cancer. However, its clinical use is limited by its cardiotoxicity. Therefore, the present study aimed to investigate if targeting ferroptosis could protect against Herceptin‑induced heart failure in an in vitro model of H9c2 cells after treatment of Herceptin, Herceptin + ferroptosis inhibitor ferrostatin‑1 (Fer‑1) or Herceptin + Deferoxamine. H9c2 cell viability was measured by MTT assay. Reactive oxygen species (ROS) levels were detected by measuring the fluorescence of DCFH‑DA‑A and MitoSOX™ Red. Glutathione (GSH)/oxidized glutathione (GSSG) ratio was measured using the GSH/GSSG Ratio Detection Assay kit. Mitochondrial membrane potential and ATP content were evaluated by JC‑1 staining and bioluminescent assay kits, respectively. Protein expressions of glutathione peroxidase 4, recombinant solute carrier family 7 member 11, mitochondrial optic atrophy1‑1/2, mitofusin, Acyl‑CoA synthetase long chain family member 4, cytochrome c, voltage‑dependent anion‑selective channel, dynamin‑related protein, mitochondrial fission 1 protein and mitochondrial ferritin were evaluated by western blotting. It was found that Herceptin reduced H9c2 cell viability whilst increasing intracellular and mitochondrial ROS levels in a dose‑ and time‑dependent manner. Furthermore, Herceptin decreased glutathione peroxidase (GPX) protein expression and the GSH/ GSSG ratio in H9c2 cells in a dose‑ and time‑dependent manner. The Fer‑1 abolished this Herceptin‑induced reduction in cell viability, GSH/GSSG ratio, mitochondrial membrane potential and ATP content. Fer‑1 also reversed the suppressive effects of Herceptin on the protein expression levels of GPX4, recombinant solute carrier family 7 member 11, mitochondrial optic atrophy1‑1/2 and mitofusin in H9c2 cells. Subsequently, Fer‑1 was found to reverse the Herceptin‑induced increase in mitochondrial ROS and iron levels in H9c2 cells, as well as the increased protein expression levels of Acyl‑CoA synthetase long chain family member 4, cytochrome c, voltage‑dependent anion‑selective channel, dynamin‑related protein, mitochondrial fission 1 protein and mitochondrial ferritin in H9c2 cells. However, compared with deferoxamine, an iron chelator, the effects of Fer‑1 were less effective. Collectively, these findings provided insights into the pathogenic mechanism that underlie Herceptin‑induced cardiomyopathy, which potentially provides a novel therapeutic target for the prevention of cardiotoxicity in HER2⁺ breast cancer treatment.